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Vertical-external-cavity surface-emitting lasers (VECSELs) are versatile lasers sources that have become particularly appealing for different applications due to the unique features they can offer. They combine the wide wavelength coverage of semiconductor laser technology with the good beam quality and power scalability of solid-state thin-disk lasers. The external cavity architectures also allow for efficient frequency conversion from infrared to visible and UV wavelengths. In this way, VECSELs can provide high-power emission with good beam quality at the most challenging wavelengths, such as the yellow spectral region. Moreover, one of their major benefits is the compact design, which is particularly important for applications.Potential applications for VECSELs are manifold and include fields such as medicine, astronomy and quantum optics research. This thesis is concerned with the medical applications, and particularly focuses on dermatologic applications requiring yellow lasers. The yellow spectral range is challenging for any laser technology, which is why not that many yellow lasers exist on the laser market. The first main objective of this thesis was to demonstrate frequency converted yellow-orange-red VECSELs in laboratory set-ups. This was followed by the development of a fully functional yellow laser based on VECSEL-technology and designed for medical use. Finally, the work was focused on performing a clinical trial designed to test the feasibility of VECSEL-technology in a dermatologic medical application.As a result of this thesis work, we have demonstrated record high output powers from laboratorybased VECSELs: 20 W at 585 nm, 10 W at 615 nm and 72 W at 1180 nm. Moreover, the performed clinical trial showed that the developed yellow VECSEL system is at least as good as the traditionally used laser in the treatment of vascular lesions (specifically telangiectasia) in terms of the treatment efficacy. In addition, the treatment times were significantly shorter with the VECSEL system than with the traditional laser thanks to the fast scanning of the light application device. With further improvements arising from the full exploitation of the laser’s power reserve, the system has the potential to be a breakthrough in the treatment of vascular-related skin conditions.

Currently, mobile devices are aware of user position, which can be provided to mobile apps for the development of tailored services known as Location-Based Services. Further advances on current Location-based Services (LBS), i.e. using any other information from the user such as gender, music preferences etc, may lead to transition from a Location-Based environment to a fully developed ContextAware environment.The current trend towards Context-aware Services (CAS) is reflected in academic research since more than twenty years as well as in the progress in Software Development Kits (SDKs) of the main mobile operating systems, where CAS frameworks are currently being used. However, there is no community agreement for modelling context CAS and little is known about the architecture of these context management frameworks of the mobile operating systems.Based on previous research in the area of CAS, I establish and analyse a reasoning architecture, the Context Engine (CE), that enables the main steps of designing and implementing context-aware services. The chief utility of CAS is their ability to formulate and encapsulate information, obtain user context through context acquisition tools and distribute it to third-party applications that build personalised services based on the provided information. The CE has the responsibility of selecting the optimal context acquisition tool to solve a concrete problem which is discussed in this dissertation.Furthermore, this thesis contributes to the development of context inference tools by studying two particular cases. The first case aims at inferring user (semantic) location information based on mobile phone usage data. This first case has been carried out in collaboration with Microsoft Finland, which provides a similar context inference solution to mobile developers through their Software Development Kit (SDK). The second case aims at inferring user information based on social network information, i.e. infer user information based on his or her connections. Both studies yield positive results and have the potential to be extended to obtain better context acquisition tools and, therefore, better user context.

Random lasers are resonator-less light sources where the optical feedback for lasing arises from recurrent multiple scattering events in a disordered gain medium. During the past 20 years, random lasers have been the subject of intense theoretical and experimental investigations due to their novelty, simplicity and ruggedness as well as their great potential for applications ranging from imaging to biomedical diagnostics. Common random lasers, however, tend to emit light in a wide range of directions with poor beam quality. The lack of pre-determined directionality and its control along with poor spatial characteristics hinder the applications of random lasers in many fields.It has been shown that dye-doped nematic liquid crystals can random lase when optically pumped within the absorption region of the dye molecules. Moreover, through molecular reorientation they support the propagation of self-guided optical beams, known as nematicons, which act as real-time graded-index optical waveguides.In order to address the problems of conventional random lasers, this Thesis focuses on the demonstration of a configuration were an efficient random laser with directional output is realized in dye-doped nematic liquid crystals by combing optical gain, random scattering, and nematicons. A planar cell filled with a mixture of commercial E7 nematic liquid crystals (host) and PM 597 (guest) is used as the material. A near infrared continuous-wave beam is used to launch a nematicon, while a 6 ns pulsed beam at 532 nm is used to optically pump the material. The synergy of random lasing and nematicons in this geometry provides several breakthrough results.By adopting a pumping geometry collinear with the nematicon, we demonstrate random laser emission from the initial region of the nematicon. The nematicon waveguide provides transverse confinement to the emitted photons, resulting in directionality, high photon collection, and high slope efficiency. The nematicon also modulates the emission, allowing the realization of a random transistor laser, where a low-power continuous-wave input is able to lower the threshold for lasing.By taking advantage of the response of nematicons to external stimuli, we also demonstrate a random laser emitting in a voltage-controlled direction. Finally, we demonstrate in-plane random laser steering by external magnetic field. The latter approach allows us to steer the random laser beam over 14°.

Polarization, which is a fundamental property of light, describes the direction of oscillation of the electric component of the optical field. It is often assumed to be transverse to the direction of propagation of the optical wave. This is, for instance, the case for paraxial, i.e., collimated or weakly focused, laser beams. For nonparaxial, i.e., tightly focused, laser beams, however, the polarization of such beams shows a three-dimensional behavior as manifested by the generation of non-vanishing fields directed along the longitudinal direction, within the focal volume. These longitudinal fields have tremendous effects in the context of optical microscopy, and especially nonlinear microscopy because of the tensorial and symmetry dependence of the nonlinear response. So far, techniques able to precisely tailor the longitudinal field components at focus have relied on cumbersome setups and have seen their capabilities hindered by the lack of appropriate probes that can be used to unambiguously and directly detect such longitudinal fields.This Thesis aims to meet this challenge and to provide new ways to control and probe longitudinal electric fields at the focus of a high numerical aperture objective. Relying on state-of-the-art spatial phase-shaping techniques of an incident optical field, we manage to control various parameters of the longitudinal electric field within the focal volume, including its transverse spatial distribution and depth of field, demonstrated by collection of second-harmonic generation from vertically aligned GaAs nanowires. The results presented in this Thesis suggest that the strength and spatial distribution of longitudinal fields can be generally controlled but also probed using our techniques. This work also opens up new opportunities for better understanding optical responses at the nanoscale and is expected to provide alternative imaging techniques for different types of nanostructures and possibly later for biological samples. Finally, our phase-shaping techniques provide alternative tools towards more advanced control of polarization in three-dimensions at focus.

The thesis covers the development of single and dual longitudinal mode distributed feedback (DFB) lasers with surface gratings. These gratings were studied since they enable regrowth-free fabrication and easy implementation of arbitrary longitudinal effective refractive index variations. Advanced transverse and longitudinal surface grating structures were modeled, simulated, and experimentally tested. Procedures for optimizing the laser structures across a wide range of parameter variations were developed. The main targets were narrow linewidth emission for optical pumping of Rubidium atomic clocks, increased direct amplitude modulation for optical communications, and photonic generation of widely tunable electrical signals in the millimeter wave band for the next generation of wireless communications.Laterally-coupled ridge-waveguide (LC-RWG) surface gratings with alternating lateral protrusions were developed to circumvent the etching aspect ratio limitation that prevents the fabrication of low-order short-wavelength surface gratings. The single longitudinal mode DFB lasers with alternating LC-RWG gratings emitting around 780 nm demonstrated improved performances, particularly important for the space borne target applications.The dual longitudinal mode emission was achieved by periodically placing phase shifts along the grating. The experiments showed that the direct amplitude modulation bandwidth is extended when the photon-photon resonance associated with dual-mode emission is properly placed with respect to the carrier-photon resonance and when both resonances are adequately damped. Difference frequency range controlled by structural variations and 40 GHz difference frequency tuning by bias were demonstrated, as well as high speed difference frequency modulation. Linearly apodized LC-RWG surface gratings enabled a lower threshold current, a higher output power, and a broader range of difference frequency tunability by bias. Also the apodization and the complex-coupling of the surface gratings enabled the use of higher facet reflectivities, leading to narrower intrinsic short timescale linewidths. The achieved performance improvements indicate that the studied laser types are promising solutions for their target applications.

This work focuses on two lipid receptors known as GM1 and phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2). GM1 is a ganglioside present in the outer plasma membrane, sensing signals from the outside of the cell, while PI(4,5)P2 is an important phosphoinositide found in the inner leaflet of the plasma membrane. Due to their vital role in cellular life, studies of the lipid–lipid and lipid–protein interactions of these receptors have become an attractive venture for researchers. Nevertheless, despite a significant amount of work, the molecular details of these interactions have remained largely unknown due to the limited temporal and spatial resolution of the current experimental methods. Here we overcome this problem by using atomistic and coarse-grained molecular dynamics simulations applied to explore the structural and dynamical properties of these lipid receptors in various membranes.In the first part of this Thesis, the functional properties of PI(4,5)P2 were studied through lipid–protein interactions between PI(4,5)P2, talin, and integrin. The simulations revealed a new means on how PI(4,5)P2 together with talin interferes with the stability of the integrin transmembrane domains, suggesting a new mechanism for the first steps of integrin activation.The second part of this Thesis focuses on various mechanisms that can alter and regulate lipid receptor binding properties. First, the binding of cholera toxin to GM1 and the fluorescent analog of the receptor was examined. A clear difference in the behavior between the native and the labeled GM1 was observed. These results highlight the importance of artifacts that fluorescent labeling can cause. Second, the intracellular calcium was shown to affect the PI(4,5)P2 headgroup tilting and the related ligand binding. Importantly, these results were directly linked to cell signaling events through experimental findings observed by our collaborators. Finally, the fundamental question as to how the PI(4,5)P2 receptor is recognized only in the plasma membrane but not in the other cell compartments was explored. Enhanced ligand binding to cholesterol-rich PI(4,5)P2 membranes was found, suggesting that the steep cholesterol gradient along the secretory pathway in a cell may be a part of the machinery coordinating the specific cell organelle recognition.Altogether, the Thesis provides novel insight on the function of lipid receptors, modulation of lipid–protein interactions, and highlights the added value gained by bridging scientific computing and novel computing tools with experimental science. Tässä työssä käsitellään GM1 ja fosfatidyyli-inositoli-4,5-bisfosfaatti (PI(4,5)P2) lipidireseptoreita. GM1 on gangliosidi, joka esiintyy solukalvon ulommaisella puolella ja vastaanottaa solun ulkopuolelta tulevia signaaleja. PI(4,5)P2 on tärkeä fosfatidyyliinositoli ja esiintyy solukalvon sytosolisella osalla. Soluille elintärkeisiin toimintoihin osallistumisen takia lipidireseptoreiden vuorovaikutukset muiden lipidien sekä proteiinien kanssa ovat olleet monien tutkimusten kohteena. Suuresta huomiosta ja panostuksesta huolimatta reseptoreiden toiminnallisista yksityiskohdista tiedetään kuitenkin edelleen verrattain vähän. Tämä johtuu nykyisten kokeellisten menetelmien haasteista tutkia pieniä nanoskaaloja sekä niiden nopeaa dynamiikkaa. Tässä työssä käytetään atomistisia sekä karkeistettuja molekyylidynamiikkasimulaatioita kyseisten lipidireseptoreiden rakenteellisten ja dynaamisten ominaisuuksien selvittämiseen.Väitöstyön ensimmäisessä osassa tutkitaan PI(4,5)P2-reseptorin vuorovaikutuksia integriinin kanssa. Simulaatiot paljastivat uuden mekanismin, jolla PI(4,5)P2 yhdessä talin-proteiinin kanssa voi häiritä integriinin kalvossa olevan osan vakautta. Tulokset tarjoavat uuden mahdollisen selityksen sille, miten integriinien aktivoitumista voidaan säädellä solukalvoissa.Jälkimmäinen osa tästä väitöstyöstä keskittyy lipidireseptorien toimintamekanismien säätelyyn. Ensiksi tutkitaan koleratoksiinin sitoutumista sekä sen luonnolliseen GM1reseptoriin että sen fluoresoivaksi muokattuun GM1-vastinpariin. Tulokset osoittavat selkeän eron proteiinin sitoutumisessa näiden reseptorien välillä, korostaen yleisesti käytettyjen fluoresoivien aineiden merkitystä ja vaikutusta tutkittaviin kohteisiin. Seuraavaksi selvitetään sytosolissa olevan kalsiumin vaikutus PI(4,5)P2-reseptoriin ja sen aiheuttamiin muutoksiin proteiinin sitoutumisessa. Tulokset yhdistetään myös solusignalointireittiin kokeellisen yhteistyön kautta. Viimeiseksi tutkitaan perusperiaatetta siitä, miten PI(4,5)P2-reseptori sitoo tiettyjä proteiineja pelkästään solukalvossa, mutta ei muissa solun soluelimissä. Tulokset havainnollistavat, että solukalvon kolesteroli parantaa proteiinien sitoutumista PI(4,5)P2-reseptoriin. Tämä voi selittää soluelinten identiteettiä, kun jo ennestään tiedetään, että kolesterolikonsentraatio muuttuu eri solukalvoissa ja on korkeimmillaan juuri plasmakalvossa.Kokonaisuutena tämä työ tarjoaa uusia näkemyksiä lipidireseptorien toiminnallisuudesta sekä lipidi–proteiini -vuorovaikutusten säätelystä. Työ korostaa laskennallisten ja kokeellisten tutkimusten yhteistyön tärkeyttä ja hyödyllisyyttä.

Electronic components must be cooled to maintain their operating temperatures below the specified limits. If the maximum permissible limit of a component is exceeded, its service life decreases considerably. With increasing power densities in recent decades, the use of heat sinks to improve component cooling has become virtually mandatory in many applications. However, designing a heat sink, which optimally compromises its material weight and its heat transfer performance, is a difficult task because the result depends heavily on its geometrical structure and its operating conditions.In this thesis, a fast way to optimize industrial heat sinks with a fixed set of heat dissipating components is presented. In a typical optimization case, several hundred temperature field evaluations are needed to find the optimal geometry. These evaluations consume a lot of CPU time if done with conventional CFD. The main objective of this thesis is, therefore, to present a new calculation model, which can handle these temperature field evaluations in a much shorter time. In the model, the speedup is obtained by replacing the slow 3D CFD -solution of air velocity and temperature distributions with 1D solutions for the mean values of these distributions, where convective heat transfer and shear stress are calculated from analytical correlations. A complete 3D numerical solution is only performed for the solid temperature field. These modifications make the new model at least a thousand times faster than CFD.The calculation model is then tested for accuracy in many test cases, where its results are compared to those calculated with CFD and analytical solutions. These comparisons ensure that the model operates with the precision needed for optimization to predict the maximum temperature of the components. This is important because, in optimization, the maximum temperature of the components is the most crucial quantity.After accuracy testing, the use of the model as part of an efficient multi-objective optimization algorithm is demonstrated in many distinct cases. Instead of just one optimal solution, multiobjective optimization results in a set of best compromise solutions, called the Pareto optimal set, according to the chosen criteria. Usually, the optimization criteria are the maximum temperature of the components and the weight of the material, or the external volume, of the heat sink. A wellperformed optimization can allow a significant reduction of the solid material used. In the heat sink manufacturing industry, the potential for total savings in material, energy, and CO2 emissions is significant as the global market size of thermal management technology is vast. Elektroniset komponentit tarvitsevat jäähdytystä, jotta niiden käyttölämpötilat pysyvät sallittujen raja-arvojen sisällä. Mikäli sallitut käyttölämpötilat ylitetään, komponenttien käyttöikä laskee merkittävästi. Haasteena onkin, että komponenttien tehotiheydet ovat kasvaneet merkittävästi viime vuosikymmeninä, jolloin niiden lämmönpoisto vaatii käytännössä jäähdytyspinta-alan kasvattamista jäähdytysrivastojen avulla. Optimaalisen jäähdytysrivaston suunnittelu ei ole kuitenkaan helppoa, koska sen geometrinen rakenne, ja käyttöympäristö, vaikuttavat sen lämmönsiirtotehoon.Tässä työssä esitetään nopea metodi tietyn komponenttijakauman jäähdyttämiseen tarkoitetun jäähdytysrivaston optimoinnille. Optimoinnissa vaaditaan yleensä vähintään satojen erilaisten rakenteiden lämpötilajakaumien laskeminen, jotta löydetään optimaalinen geometria. Nämä laskennat kuluttavat paljon CPU-aikaa, jos ne tehdään virtauslaskennalla (CFD). Ratkaisuna tässä työssä esitetään nopea laskentamalli, joka suoriutuu lämpötilakentän laskennasta huomattavasti CFD:tä nopeammin. Laskentamallissa hyödynnetään nopeita 1D-ratkaisuja ilmavirtauksen keskimääräisille nopeus- ja lämpötilajakaumille, ja niillä korvataan CFD:n yksityiskohtaisemmat ilman nopeus- ja lämpötilajakaumien 3D-ratkaisut. Ainoastaan jäähdytysrivaston lämpötilakenttä ratkaistaan kolmiulotteisesti. Näillä muutoksilla uusi laskentamalli on yli tuhat kertaa CFD:tä nopeampi jäähdytysrivaston lämpötilakentän laskennassa.Laskentamallin soveltuvuutta optimointiin testattiin vertailemalla sillä laskettuja arvoja analyyttisiin laskentoihin, CFD-laskentoihin ja kokeellisiin tuloksiin. Laskentamallin antamat tulokset komponenttien maksimilämpötiloille poikkesivat alle 10 % vertailuarvoista kaikissa testitapauksissa. Tulos oli hyvä, koska maksimilämpötilan tarkka laskenta on tärkeää optimoinnin onnistumisen kannalta.Laskentamallia käytettiin maksimilämpötilojen määrittämiseen monitavoitteisessa optimoinnissa, jossa etsitään matemaattisesti parhaat kompromissit, Pareto optimaaliset ratkaisut, valittujen kriteerien mukaan. Useimmiten optimointikriteerit ovat komponenttien maksimilämpötilat, rivaston massa ja ulkotilavuus. Optimoinnin avulla voidaan saavuttaa merkittäviä materiaalisäästöjä. Esimerkiksi tyypillisessä tämän työn tapauksessa jäähdytysrivaston massaa saatiin vähennettyä noin 50 %. Koska kansainvälisten markkinoiden koko tehostetulle lämmönsiirrolle on valtava, optimoinnilla voidaan saavuttaa merkittäviä kokonaissäästöjä materiaalin ja energian kulutuksessa sekä CO2-päästöissä.

Understanding the structure and dynamics of trees and forest is key in studying the environment and understanding current and future climates. Development has been fast in measurement technology for these purposes, as it is currently possible to measure forest terrestrially with photography-based instruments or either static or mobile laser scanning, and airborne using drones, helicopters or aeroplanes, and even from space using satellitemounted instruments. However, as all these measurements are indirect presentations of the key attributes to study, they require powerful analysis methods to accompany them. This thesis focuses on terrestrial laser scanning data and presents a method for reconstructing comprehensive, quantitative structure models of trees from such data. The method is designed to be a tool for understanding tree and forest structure, as well as, dynamics and functionality, without the need for destructive measurements. The reconstructed models provide access to tree attributes previously impossible or laborious to measure, either at a single tree-scale, at forest-plot-scale or even at forest-scale. The thesis will present the reconstruction method and will focus on two of its applications: automatic tree species recognition and augmenting the produced structure models with leaves or needles, enabling more accurate simulations involving light propagation and plant interaction with the atmosphere. Additionally, parts of the thesis describe forms of dissemination used to promote the reconstruction method and its applications, increasing the rate of adoption into operational use. The dissemination approaches include several animations, interactive 3D models and open-source software.

In the era of globalization, the spread of infectious diseases is a serious concern. The emergence of drug resistant bacteria and healthcare associated infections in particular, poses a great danger to human health. Self-disinfecting surfaces may play a significant role in controlling the spread of pathogenic diseases. Photodynamic antimicrobial chemotherapy (PACT) can be a very efficient way of inactivation of drug resistant bacteria and biofilms. However, making a self-disinfecting surface based on PACT principles requires novel photosensitizers, which can efficiently generate reactive oxygen species, and are stable and accessible. In this thesis, attempts are undertaken to synthesize novel photosensitizers based on peryleneimides and phthalocyanines. We propose a novel efficient method for the direct and regioselective amination of peryleneimides. The substitution occurs with high yields exclusively at 1,6- and 7,12-positions of the bay region of perylenediimide and perylenemonoimide diester. We also report the synthesis of novel cationic peryleneimides, which can be potentially used as photosensitizers in PACT. Phthalocyanines are known to be efficient photosensitizers. In this thesis we present the synthesis of novel pyridinyl-substituted phthalocyanine and its tetracationic derivatives. As a unique synthetic approach, pyridinyl groups are connected to α-phthalo positions of the macrocycle via direct C-C bonds. Prototype self-disinfecting materials are prepared by impregnating filter paper with the synthesized dyes. Binding of the dyes occurs via electrostatic interactions and does not require any special chemical modification. A fast and simple setup for the evaluation of antimicrobial efficacies of dyed papers is proposed. The setup employs bioluminescent bacteria and allows for a fast screening of a large number of dyes. According to the screening results, tetracationic phthalocyanines are the most efficient antimicrobial photosensitizers. The antimicrobial efficacies of phthalocyanine derivatives are evaluated quantitatively with the help of colony forming unit (CFU) counting method. The papers impregnated with as little as 80 mg/m2 of cationic zinc phthalocyanine exhibit 2.7 and 3.4 log reduction in CFU against Escherichia coli (E. coli) and Acinetobacter baylyi (A. baylyi), respectively after illumination with the light intensity 18 mW/cm2 in a solar simulator. Similar antimicrobial efficacies are achieved under illumination with consumer light emitting diode (LED) lights. Phthalocyanine-impregnated papers show very good stability. Incubation of the dye-impregnated papers in phosphatebuffered saline demonstrates superior binding ability of phthalocyanine, with basically no detectable leaching of the dye. Photostability of the dyed paper is also high. Continuous illumination with 42 mW/cm2 LED light for 64 h decreases the absorptance of dyed papers only by 10%.

Integral membrane proteins are tiny factories with big responsibilities in signaling and transport. These proteins are constantly looking for oligomerization partners and favorable lipid environments to perform their functions that are critical for our health. The search processes are driven by thermally-agitated lateral diffusion. Cellular membranes are crowded and highly heterogeneous entities. Their structure is assumed to couple to the dynamics of molecules within the membrane, rendering diffusion therein complex too. Clarifying this connection can help us to grasp how cells regulate dynamic processes by locally varying their membrane properties, and how this further affects protein function. Unfortunately, despite persistent experimental work, our understanding of this structure–dynamics–function coupling remains poor.In this Thesis, we present our findings on how protein crowding and lipid packing affect the lateral dynamics of lipids and proteins in membranes and monolayers. We have employed molecular dynamics simulations using both atomistic and coarsegrained models to resolve how the rate and nature of diffusion are affected by these two factors. We also advanced the related methodology, which turned out to be beneficial for studying lipid membranes that are crowded with proteins.We find that crowding and packing slow down lipid and protein diffusion and extend the anomalous diffusion regime. We demonstrate that models used to predict diffusion coefficients of lipids and proteins struggle in such conditions. Finally, we observe that protein crowding effects non-Gaussian diffusion that does not follow the diffusion mechanism observed for protein-free bilayers, nor any other known mechanism.Our observations help us understand the dynamics in crowded membranes, and hence shed light on the kinetics of numerous membrane-mediated phenomena. The findings suggest that normal diffusion is likely absent in the membranes of living cells, where the motion of each lipid and protein is heavily affected by its heterogeneous surroundings. The results also pave the way towards understanding central processes in the utterly complex plasma membranes of living cells. Here, the possible future applications lie in pharmaceuticals that affect protein function by disturbing the formation of functional protein–protein or protein–lipid units by perturbing the dynamic properties of the membranes and monolayers.

Fossil fuels, coal and oil are used for energy production around the world. Combustion of these fossil fuels produces gases and particles that affect air quality and climate. The CO2 emissions can be decreased by substituting fossil fuels with biomass and this substitution can further affect the particle emissions of the power plants. This thesis focuses on characterising particles of real-scale power plants with various fuels, from combustion to atmospheric dilution. The studied power plants were a combined heat-and-power (CHP) plant (combusting coal and a coal – wood pellet mixture) and a heating plant with three fuel mixtures. The particles were characterised mainly based on particle number size distribution and number concentration, using aerosol sampling from the superheater area of the boiler of the CHP plant, the stack of the CHP and the heating plant and the atmosphere surrounding the CHP plant.Measurements for the aerosol samples taken from the boiler indicated that the particles from the combustion of coal and the mixture of coal and industrial pellets had already formed in the boiler. The formation of the particles was studied by changing the dilution of the aerosol sample and by comparing the electrical charges of the particles in the boiler. The coal-combustion particles were around 25 nm in diameter. The addition of 10.5% industrial pellets to the coal caused the formation of a second particle mode, the soot mode (120 nm in diameter), in the boiler. In the heating plant, the addition of light fuel oil to heavy fuel oil had a similar effect on the oil-combustion particles. The particles from the combined coal-and-pellet combustion agglomerated and coagulated before reaching the sampling point in the stack. These processes, combined with the effect of an electrostatic precipitator, resulted the mean diameter of the particles to be 80 nm. Further, the flue-gas desulphurisation and fabric filters lowered the particle number concentrations. The particles measured inside the stack were also observed from the atmosphere before they were diluted to background concentrations. The flue-gas plume was measured in four occasions, in three wind directions and with four flue-gas cleaning and fuel combinations. These measurements resulted in the observation of a new particle formation in the diluting plume. In the atmospheric measurements, the concentrations of SO2 and CO2 played an important role in measuring the dilution process. In the heating-plant experiment, the characterization of oil-combustion particles showed that the lower fuel sulphur content decreased the particles’ hygroscopic growth factors.The atmospheric primary emissions of coal-fired power plants can be effectively lowered through flue-gas cleaning technologies. In this study, flue-gas cleaning was shown to affect the flue gas’s particle number and the mass concentration as well as its black carbon concentration. The cleaning did not prevent new particle formation in the flue-gas plume in the atmosphere, but it did reduce the potential for particle formation.

Ischemic heart disease and stroke are the leading causes of death in the industrialized countries. The driving mechanism behind these diseases is the atherosclerotic process leading to narrowing of the arteries and eventually a reduction of blood supply to the target organs. Lipoproteins known as carriers of cholesterol play an essential role in that process. However, despite intensive research over more than 100 years, the molecular level structure and function of lipoproteins are not fully understood. This largely stems from the fact that due to the small size and the dynamic nature of lipoproteins, experimental techniques are not able to gauge lipoprotein structure and dynamics in sufficient detail. Meanwhile, molecular dynamics (MD) simulation has proved to be a powerful and simple method to explore the properties of various biological systems and to overcome many limitations of experimental techniques. In this thesis, the MD method was used to study lipoproteins at the molecular level. To this end, coarse-grained molecular models for high- and low-density lipoprotein (HDL and LDL, respectively) particles were constructed to study their structure and dynamics. Further, atomic-scale models were used to study the interaction between HDL and CETP, a lipid transfer protein. Finally, atomic simulations were also employed in a lipoprotein-like environment to assess the validity of using BODIPY, a common molecular probe, to explore lipoprotein properties.The first key result of this thesis is the detailed structural model found for both HDL and LDL, showing that the previously proposed 2- and 3-layer models are inadequate for describing lipoprotein structure to a sufficient degree. It was found that the structural and dynamic properties of lipids hosted by lipoproteins depend significantly on their location and distance from the center of the particle. Second, this thesis work revealed the mechanism and the residues involved in anchoring CETP to the surface of lipoprotein particles. Also, the critical role of helix X as a door to the hydrophobic tunnel carrying the cargo lipids was clarified. Third, based on BODIPY-simulations reported in this thesis one can conclude that BODIPY-labeled cholesteryl oleate is not a suitable probe for experimental cholesteryl oleate tracking studies in lipoprotein environments. It appears that a successful probe in a lipoprotein environment should have no significant affinity for the hydrophilic surface region.The findings give a solid grounds for further studies to explore the key initial steps associated with atherosclerosis and also the molecular-level events in the lipid exchange processes. For future purposes, this work demonstrates that the used simulation methods are particularly useful for studies of, e.g., the coupling between the lipid composition of lipoprotein particles and their structure and function.

Over the past few years, the torrefaction process has evolved into a promising pre-treatment process to improve the properties of biomass to a level at which it is competitive with coal. However, in order to make torrefied biomass pellets an economically viable alternative to coal and wood pellets, the techno-economic feasibility of the torrefaction process needs to be improved. Thus, new process configurations are required to produce torrefied biomass pellets and other high value products from the torrefaction process. This thesis presents new process configurations, which have been evaluated with laboratory experiments, process simulations and mathematical modeling.Two different biomass samples i.e. eucalyptus clone and pinewood were used in torrefaction experiments. Initially, the effect that torrefaction pretreatment has on the kinetics, reaction mechanisms and heat flow during biomass pyrolysis was studied using TGA and DSC analysis. The results showed that the pyrolysis reaction mechanism varied significantly with torrefaction treatment. The heat flow data from DSC showed that torrefied biomass pyrolysis requires more energy than dried biomass in order to initiate the pyrolysis reactions.In the second stage, the anaerobic digestion of torrefaction condensate for the efficient utilization of torrefaction volatiles was studied through batch anaerobic digestion assays. Torrefaction condensate produced at 225, 275 and 300 °C was used at various substrate to inoculum ratio i.e. 0.1, 0.2 and 0.5. The methane yield was in the range of 430 - 492 mL/g volatile solids (VS) and 430 - 460 mL/g VS under mesophilic and thermophilic conditions, respectively. With the higher loading, i.e. > 0.2 VSsubstrate:VSinoculum, the production of methane was inhibited because of the inhibitory compounds in the torrefaction condensate, such as furfural and guaiacol.Large quantities of binders are required to make the pelletization process effective and to improve the quality of the pellets. An innovative process configuration is hereby proposed for detoxifying the torrefaction condensate and to reduce the binders’ requirement. The removal of a major inhibitory compound, i.e. furfural, through adsorption using torrefied biomass as an adsorbent was also studied. The adsorption of furfural from the torrefaction condensate at 250 g/L dosage was around 54%. Finally, the influence of the detoxification of the torrefaction condensate on the AD process was studied through batch assays.Finally, the experimental results were used to simulate industrial scale operations to evaluate the feasibility of integrating the torrefaction process with anaerobic digestion. In addition, different process integration approaches were studied to identify possible heat energy recovery options in the torrefaction process, on its own, and also when integrated with AD. The standalone torrefaction process was compared with three different process configurations, which varied according to the intended application for the produced biogas. The mass balance showed that biomethane can be produced at 369 m3/h, at 10 t/h of torrefied biomass pellets production capacity. A sensitivity analysis showed that the cost of the feedstock has a significant effect on the economics of the overall process. The economic analysis showed that the price of torrefied biomass pellets could be significantly reduced if the torrefaction process is integrated with AD.

This thesis collects together research results obtained during my doctoral studies related to approximate Bayesian inference in stochastic state-space models. The published research spans a variety of topics including 1) application of Gaussian filtering in satellite orbit prediction, 2) outlier robust linear regression using variational Bayes (VB) approximation, 3) filtering and smoothing in continuous-discrete Gaussian models using VB approximation and 4) parameter estimation using twisted particle filters. The main goal of the introductory part of the thesis is to connect the results to the general framework of estimation of state and model parameters and present them in a unified manner.Bayesian inference for non-linear state space models generally requires use of approximations, since the exact posterior distribution is readily available only for a few special cases. The approximation methods can be roughly classified into to groups: deterministic methods, where the intractable posterior distribution is approximated from a family of more tractable distributions (e.g. Gaussian and VB approximations), and stochastic sampling based methods (e.g. particle filters). Gaussian approximation refers to directly approximating the posterior with a Gaussian distribution, and can be readily applied for models with Gaussian process and measurement noise. Well known examples are the extended Kalman filter and sigma-point based unscented Kalman filter. The VB method is based on minimizing the Kullback-Leibler divergence of the true posterior with respect to the approximate distribution, chosen from a family of more tractable simpler distributions.The first main contribution of the thesis is the development of a VB approximation for linear regression problems with outlier robust measurement distributions. A broad family of outlier robust distributions can be presented as an infinite mixture of Gaussians, called Gaussian scale mixture models, and include e.g. the t-distribution, the Laplace distribution and the contaminated normal distribution. The VB approximation for the regression problem can be readily extended to the estimation of state space models and is presented in the introductory part.VB approximations can be also used for approximate inference in continuous-discrete Gaussian models, where the dynamics are modeled with stochastic differential equations and measurements are obtained at discrete time instants. The second main contribution is the presentation of a VB approximation for these models and the explanation of how the resulting algorithm connects to the Gaussian filtering and smoothing framework.The third contribution of the thesis is the development of parameter estimation using particle Markov Chain Monte Carlo (PMCMC) method and twisted particle filters. Twisted particle filters are obtained from standard particle filters by applying a special weighting to the sampling law of the filter. The weighting is chosen to minimize the variance of the marginal likelihood estimate, and the resulting particle filter is more efficient than conventional PMCMC algorithms. The exact optimal weighting is generally not available, but can be approximated using the Gaussian filtering and smoothing framework.

Dye-sensitized solar cells are composed of cheap and recyclable materials. These colorful and flexible cells convert sunlight into renewable energy. However, dye-sensitized solar cells are inefficient due to their low-charge current. The goal of this thesis is thus to create better understanding of the various components of these cells in order to improve their efficiencies. The main focus of dye-sensitized solar energy research lies in charge-transfer reactions between three main components: dye molecule; semiconductor surface, and electrolyte. In dye-sensitized solar cells, the charge is transferred from the excited dye molecule to the semiconductor surface. The charge is then transported to the electrode to create the electric current.The studied components are derivatives of boron-dipyrromethene, perylene monoimide, and trisphenyl amine as dye molecules. Nickel oxide and titanium dioxide are used as semiconductor surfaces. The studied anchoring groups are carboxylate, 1,2-diol, and pyridine. These are studied in isolation, and then, their interactions in contact are investigated. In this study theoretical modeling is used, which includes the hybrid functional B3LYP and CRYSTAL09 software. The hybrid functional, B3LYP, is not widely used in studies within periodic boundary conditions such as dye-semiconductor interfaces. Thus, the mentioned systems have not been studied earlier at this level of theory.In the first part of the study, the isolated systems, namely derivatives borondipyrromethene and titanium dioxide, are investigated. Results with BODIPY show that i) the vinylene group makes no difference for the electron transition nor orbital localization of orbitals, ii) phosphonate draws the most and carboxyl the least amount of the electron localization from the anchor, iii) methyl groups block completely the electron localization from the anchoring group, and iv) the absence of donor decreases the energy of HOMO level. BODIPY with vinylene and methyl groups were chosen for the synthesis, because the methyl groups increase the life-time of electron–hole pair. Doping with nitrogen shows that the amount of nitrogen atoms makes difference for electronic structure, yet do not distort the lattice. The electronic structure changes due to the created empty gaps states that enhance electron conductivity.In the second part of this study, derivates of perylenemonoimide based dye molecules trisphenyl amine based anchoring groups on the NiO(100) surface and their interactions are investigated. The study with complete dye molecules on the nickel oxide surface is straightforward: the dyes’ highest occupied molecular orbital is above nickel oxide’s valence band maximum, thus, the spontaneous charge transfer is hard to obtain. Next it is shown that the anchoring group impacts the energy level alignment because of created dipole moment of the system that creates a shift within an electrostatic potential. Due to the shift, the highest occupied molecular orbitals of the dye molecule are either above (in case of carboxylate) or below (in the cases of pyridine and 1,2-diol) valence band maximum. In the case of complete molecules, which have the carboxylate as an anchoring group, HOMOs are above the VBM.The results and analysis of the study show the importance of the size of the molecule and the anchoring group. The smaller the dye molecule, the smaller the distances are inside the interacting system, and shorter distances to transfer the charge. In the case of complete molecules, which have the carboxylate as an anchoring group, HOMOs are above the VBM. In conclusion, the largest effect is caused by the anchoring group inside the interacting system.

Microbial synthesis of long-chain hydrocarbons is considered a promising method for the production of drop-in replacements for the currently utilized fossil fuels and chemicals. In a sustainable future, the carbon and energy required for the synthesis of these compounds should be ultimately derived from carbon dioxide (CO2) and the sun. Additionally, the produced compounds should be of similar or higher quality than the fossil counterparts they aim to replace, enabling their utilization directly in the existing processes and infrastructure. Solar energy can be efficiently captured by man-made devices, and converted to electricity. Some microbes are capable of utilizing the electrical energy for the reduction of CO2 into organic molecules, while other microbes hold the potential for the specific production of long-chain hydrocarbons. However, these two processes are difficult to achieve efficiently in any single organism, owing to their contrasting requirements for the host cells’ metabolism.In this study, a two-stage bacterial platform for the production of long-chain hydrocarbons from carbon dioxide was developed. In the first stage, acetogenic bacteria produce acetate from carbon dioxide and electricity as the sole sources of carbon and energy. In the second stage, the acetate is converted to long-chain hydrocarbons by a second bacterium, Acinetobacter baylyi. The platform is modular in nature, and different acetate-producing and -consuming processes can be combined. The final product can be determined and the production enhanced by genetically engineering A. baylyi.Fatty aldehydes are specific intermediates in the biosynthesis of wax esters and alkanes. Fatty acyl-CoA reductases (FARs) are key enzymes in the production of fatty aldehydes. The natural fatty aldehyde production of A. baylyi was improved by overexpressing either native or heterologous FARs. The overexpression led to increased fatty aldehyde production, and enabled more efficient wax ester or alkane production, depending on the downstream pathway utilized. For the wax ester production, the native wax ester production pathway of A. baylyi, combined with the overexpression of the native FAR or a previously uncharacterized, putative reductase from Nevskia ramosa, was employed. The overexpression of either of these reductases led to increased wax ester production, resulting in the highest wax ester titers reported thus far for microbial production systems. A. baylyi does not naturally produce alkanes, but the expression of a two-step cyanobacterial pathway consisting of aldehyde- and alkane producing enzymes led to alkane synthesis. Furthermore, the natural ability of A. baylyi for alkane degradation was removed, thereby converting the natural alkane degrader into alkane producer.The development of efficient production strains by metabolic engineering is restricted by the lack of sensitive and specific measurement methods for the target compounds. Intracellular biosensors may offer convenient means for high-throughput screening and optimization of the production strains. In order to study heterologous alkane biosynthesis in A. baylyi, an in vivo alkane biosensor working on two levels was developed. First, a gene encoding the green fluorescent protein (GFP) was placed under an alkane-inducible promoter, linking the alkane production to the expression of GFP. The second level is provided by a constantly expressed bacterial luciferase LuxAB, which utilizes the fatty aldehyde intermediate as a substrate in a reaction that produces visible light. Thus, the production of fatty aldehydes can be monitored with the luminescence signal. The two-level configuration of the sensor enabled the screening of different alkane-producing pathways, and the optimization of the expression levels of the pathway enzymes in order to improve the alkane biosynthesis in A. baylyi.In summary, the production of wax esters from CO2 and electricity, as well as long-chain alkanes from CO2 and H2 were demonstrated with the two-stage bacterial platform. In addition, heterologous alkane biosynthesis was demonstrated in A. baylyi, and the natural wax ester production of A. baylyi was improved by metabolic engineering. Even though the platform holds potential for the sustainable production of drop-in fuels and chemicals, significant improvements in the production efficiency are required before the potential can be realized.

Aerosol measurements are conducted in several applications, such as in air quality and emission analysis. This thesis focuses on electrical aerosol instrumentation, in which the aerosol detection is achieved by measuring electric current from charged particles. If particle charge is known accurately, the current produced by particles can be used as an accurate and traceable concentration reference in calibration of various aerosol instruments. Additionally, same methods can be applied with small modifications in the measurement of particle charge. These form the main objectives of this thesis, which are to develop particle charge measurement and aerosol instrument calibration methods in a size range from nanometers to micrometers.In this thesis, the operation of the Electrical Low Pressure Impactor (ELPI+) is introduced. The instrument contains two main components, charger and impactor, which were characterized in calibration measurements. The ELPI+ and the Differential Mobility Analyzer (DMA) were used as a basis of the developed DMA-ELPI particle charge measurement method, in which particles are classified according to their electrical mobility, which is a function of particle size and charge. This is followed by aerodynamic size classification and detection with an ELPI+. The main advantage of the developed method is the wide particle size range compared to other available techniques. The charge measurement was successfully tested using particles with well-defined size distributions and charging states. Additionally, an instrument called BOLAR was developed for studying charge from inhaler-generated particles. The BOLAR is capable of measuring the size fractioned bipolar charging state of aerosol particles. The operation of the instrument was verified with calibration measurements, and the instrument was applied in studying charge of inhaler-generated particles. As a final application of electrical aerosol instrumentation, a new wide size range instrument calibration setup was developed. This included designing and constructing a particle growth unit, an electrical mobility classifier for μm-sized particles and a flow mixing and splitting assembly. All these components were characterized, and the setup was used to calibrate a particle counter traceably in the size range from 3.6 nm to 5.3 μm, which has not previously been possible with any single setup. The introduced high accuracy calibration method can be used as a traceable primary standard for particle number concentration.

Microorganisms can be used in bioprocesses to produce various chemicals, such as fuels, cosmetics and medical products, as an environmentally friendly alternative for chemical synthesis. In these bioprocesses the raw materials (e.g. lignocellulose) can be converted to compounds with high complexity with a minimum energy input and waste material production. The metabolic capabilities and robustness of the bioprocess host organism limit the yield and purity of the product. Molecules that currently cannot be produced efficiently with robust microbial host organisms include wax esters, which have several industrial applications and are currently produced with the Jojoba plant.Acinetobacter baylyi ADP1 is a non-pathogenic soil bacterium that produces wax esters that can readily incorporate foreign DNA into their genome and utilize various plant-derived molecules as a carbon source. For these reasons, A. baylyi ADP1 has become a model organism of bacterial genetics and metabolism, which has led to the accumulation of a vast amount of information about its biology. This Doctor of Science thesis describes experiments where the metabolism of A. baylyi ADP1 was engineered for improved growth and wax ester production using lignocellulose-derived molecules as raw material.With a gene knockout (rmlA) and expression of a foreign gene (pykF), it was possible to double the growth rate of A. baylyi APD1 on glucose, double the molar wax ester yield from glucose while improving product purity and collection of the cells. An additional gene knockout (poxB) improved growth and wax ester production in the presence of acetate, a common growth inhibitor found in lignocellulosic hydrolysates. A combination of these modifications led to a strain that produced 0.45 g/l of wax esters in a medium containing glucose, amino acids from casein hydrolysate and acetate as carbon sources. In addition, a biodetoxification strain for the removal of inhibitors produced in the pretreatment of lignocellulosic biomass was produced with a single gene knockout.While significant improvements in growth and wax ester production of A. baylyi ADP1 from components of lignocellulosic hydrolysates were obtained with metabolic engineering, the wax ester production needs to be further improved if this strain is going to be used in industrial applications. The strains that were produced here can be used as platform for further improvements of wax ester production by A. baylyi ADP1.

The growing concern for the air quality in urban areas and the subsequent development of measurement networks has increased the need for lightweight and cost-effective air quality instrumentation. In urban areas, traffic-related emissions are one of the major contributors to the worsened air quality, which in turn has led to the stringed emission regulations set for vehicles. These regulations necessitate both on-board monitoring of the operation of the exhaust after-treatment devices and measurement of the real-word driving emissions with portable emission measurement systems. Both of these aspects increase the demand for sensor-type instrumentation for emission measurement.This thesis focusses on the development of diffusion charging–based aerosol instrumentation towards more compact and sensor-type instruments. The work was started by developing an add-on module for the electrical low-pressure impactor. This extended the instrument measurement capabilities by enabling the measurement of the effective density of particles in real-time. Focussing more on the sensor-type instrumentation, three different sensors were presented for measuring particle emission directly from the exhaust line: Two of them targeting the engine laboratory work or for the portable emission measurement and one designed for on-board diagnostics. The instrument developed for the on-board emission measurement provided a very good temporal performance owing to the miniaturisation of the instrument design. Lastly, a new sensor design approach was presented in which the flow rate dependence of the instruments response is minimised. This, together with the minimised pressure drop in the design, helps in lowering the instrument cost by promoting the use of a low-cost fan for generating the sample flow.Instrument response characterisation and response modelling made a central part of the study. Results from the characterisation measurements were presented for all instruments, and comprehensive response models were built for the sensor-type instruments. Depending on the instrument, both simplified approximations and theoretical responses of the instrument components were used as the starting point for the response models. Additionally, the instrument performance was demonstrated in practical measurements related to the application of each instrument. The obtained response models provide necessary information for the instrument performance evaluation and the measurement data processing.

Extremely acidic water with high metal concentrations is often produced during mining and processing of sulfidic ores. Sulfur-oxidizing microorganisms contribute significantly to the acidification of the water streams and oxygen depletion by oxidizing reduced inorganic sulfur compounds (RISCs) — which are released to the mining waters during the processing of sulfide minerals — to sulfuric acid. The acidic water continues leaching metals from minerals and the metal concentrations thus further increase.Certain metals can be recovered from acidic solutions by using them as the electron acceptor at the cathode of an electrochemical system. The metal ions accept electrons from an electrode and deposit on the surface of the electrode in pure elemental form. The electrical current required for the electrodeposition of metals is conventionally drawn from the oxidation of water. However, with the assist of electroactive microorganisms, biodegradable compounds can be used as the source of the required energy. Electroactive microorganisms oxidize a substrate and donate electrons to an anode electrode. The flow of electrons from anode to cathode creates electrical current, which can be utilized in the electrodeposition of the metals. As mining waters do not usually contain organic compounds, RISCs are promising substrates for the recovery of metals from mining waters — they are present in the same stream and can be oxidized at lower potential than water. In addition, with the electrochemical treatment both metals and RISCs could be removed from the water streams simultaneously.The aim of this work was to use tetrathionate (S4O62-) as the substrate for bioelectrochemical and electrochemical current generation. The possibility to spontaneously produce electricity from tetrathionate was first studied in microbial fuel cells (Paper I). After successful electricity production was obtained, a tetrathionate-fed microbial fuel cell was monitored for over 740 days to determine the long-term stability of such systems (Paper II). The anode potential was then externally adjusted in order to determine the minimum anode potential required for bioelectrochemical and electrochemical tetrathionate degradation (Paper III). Finally, the external voltage required for the simultaneous removal of tetrathionate and copper was determined (Paper IV).The experiments were conducted using two-chamber flow through reactors at room temperature (22±5 °C) and highly acidic conditions (pH < 2.5). The initial lag-time for electricity production from tetrathionate was relatively long in bioelectrochemical systems (approximately 100 days), but spontaneous electricity production was proven successful with ferric iron as the cathodic electron acceptor. By optimizing the external resistance, the current density was successfully improved from 80 mA m-2 (1000 Ω) to 225 mA m-2 (100 Ω). In the long-term experiment, biofouling or accumulating reaction products were not observed to limit the electricity production even after 740 days of operation. The minimum anode potential for tetrathionate degradation was observed to be 0.3 V vs. Ag/AgCl in the bioelectrochemical systems and 0.5 V in the abiotic electrochemical systems. Higher tetrathionate degradation rates were obtained in the bioelectrochemical systems (>110 mg L-1 d-1) than in the electrochemical systems (This study demonstrates for the first time that tetrathionate can be used the substrate for bioelectrochemical current generation. In bioelectrochemical systems with an efficient catholyte, tetrathionate is degraded and electricity is produced spontaneously, but abiotic electrochemical degradation requires external energy. Both bioelectrochemical and electrochemical systems provided higher current densities than a water-oxidizing control reactor when controlling the anode potential or applying external voltage. The simultaneous removal of tetrathionate and copper shows that bioelectrochemical and electrochemical systems are promising alternatives for the treatment of mining waters.

Aerosol particles interact with surfaces in different environments and applications. The knowledge of fundamental surface interaction phenomena can be used to investigate the structural properties of particles, describe the performance of different instruments, and develop new applications. In this thesis, particle rebound from a surface as well as the transfer of the electric charge during rebound and resuspension were studied. The research was based on the experimental and numerical characterization of these surface interaction phenomena. Along with the fundamental understanding obtained for the interaction between aerosol particles and surfaces, new methods were developed and applied for specific aerosols, such as fungal spores.The critical velocity of rebound, which is the smallest incident velocity for a particle to rebound, was determined in a wide particle size range combining the separate groups of previous results. The main instrument developed during the research of this thesis, a variable nozzle area impactor (VNAI), was used throughout the wide size range for different particle and surface materials. The particle material was found to have a significant effect on the critical velocity of rebound. On the contrary, the effect of the surface material was observed to be much smaller, at least for the hard surface materials studied in the experiments. Also the critical velocity for oblique impacts in the impactor was characterized. It was found that the critical velocity of rebound significantly decreased with the increasing obliquity of the impact. Based on the results of this thesis, the effect of materials and obliquity on the critical velocity can be estimated quantitatively and exploited in the development of new applications, such as impactors and collectors.The triboelectric charge transfer during rebound was characterized for nanoparticles with a new simplified method developed for an electrical low pressure impactor (ELPI). In addition, the charge transfer was measured for fungal spores and standard test dusts during rebound and resuspension. The results of this thesis showed that the triboelectric charging of particles during resuspension correlated with the triboelectric charging during rebound. Spores of different fungal species were found to obtain both positive and negative charges from substrates of different materials. The information on the triboelectric charging and rebound behavior can be used for predicting the particle dynamics in different environments and designing new applications, for instance, in ventilation and filtration systems.

This thesis studied the role of inorganic elements in biomass gasification, focusing on catalytic effects in char gasification and removal of toxic metals from the product gas. A combination of experimental, including gasification using thermogravimetric analysis and fluidized beds, and modeling techniques were used.Spruce and birch woods were leached of the naturally occurring ash forming elements and loaded with varying amounts of calcium or potassium. These woods were then gasified in either an isothermal thermogravimetric analysis device or a bubbling fluidized bed reactor. In the case of the spruce wood gasified using the thermogravimetric analysis device, char conversion models were evaluated against the measured data and an empirical model was developed which uses the concentration of calcium and potassium in wood to predict the conversion rate behavior of the char when gasified in CO2 . The results from the fluidized bed gasification tests of birch wood showed that calcium was the primary active catalyst in the wood and the increased reactivity resulting from calcium doping was clear even in the much larger scale of a fluidized bed compared to the thermogravimetric analysis. The potassium doped samples did not exhibit increased reactivity in the fluidized bed due a nonreactive layer of secondary char being deposited on the char surface.The behavior of arsenic in the product gas of chromated-copper arsenate wood was modeled using equilibrium calculations and measured experimentally in a bubbling fluidized bed. The equilibrium model accurately predicted that the product gas could be cleaned by cooling the gas below 260°C and filtering to remove condensed arsenic.While there are methods for modeling the effects of inorganics in catalyzing char gasification, further research into interconnected issues of surface area, pore sizes, pyrolysis conditions and inorganic concentrations is needed. Similarly, while equilibrium modeling has been shown to predict the behavior of arsenic during gasification in some cases, there are many gaps in understanding which arsenic compounds are most relevant.

In the present thesis, we will focus on a less studied aspect of Thomas-Fermi theory: the highly non-trivial scaling relations following from it. The main objective of this thesis is to introduce this scaling approach, not as a method to solve the many-body problem, but as an efficient way of organizing the information contained in its solution in order to extract yet more – sometimes non-trivial – information. To this goal we apply the scaling approach to a wide range of system, from nanostructures (quantum dots) to atoms and atomic ions.Our main findings can be summarized as follows: (i) the obtainment of scaling relations for the correlation energy of quantum dots and atomic ions, respectively. This allows us to extend our scaling approach to complex quantities that are beyond mean-field methods; (ii) the obtainment of scaling relations for the chemical potentials and addition energies of two-dimensional quantum dots, which allows us to compare our results to experimental data; and (iii) the obtainment of scaling relations for the ground-state energy, chemical potentials, and addition energies of three-dimensional quantum dots, which allows us to explore the dimensionality effects on the scaling relations.In all cases, we not only showed the functional form of the scaling relations, but we also provided explicit analytical expressions for the scaled quantities. Such expressions are not simple by-products of the approach, but approximations that can be used for estimating relevant quantities with practically no computational cost. Furthermore, the obtained scaling relation may serve as a starting point for the improvement of more elaborated theories, for example, in the optimization of density functionals within density functional theory.The above results are reported in four publications which constitute the basis of the thesis.

Nonlinear physical systems are ubiquitous in nature - formation of sand dunes, currents occuring in a rapidly flowing river or a simple double rod pedulum are just a few examples from everyday life. Studying and understanding these systems has interested scientists for decades. Because these nonlinear systems might be chaotic, measurements of such systems need to be performed on a real-time basis and by statistical analysis methods.The propagation of short and intense pulses in optical fibers are another well-known example of nonlinear systems. However, the rapid fluctuations of optical fields has prohibited studying these systems on a real-time basis, until recent years. This thesis demonstrates the use of state-of-the-art real-time measurement techniques to capture the stochastic dynamics of noise-seeded nonlinear processes in optical fibers allowing for novel insights and interpretation within analytical frameworks.In particular, we characterize noisy picosecond pulse train emerging from spontaneous modulation instability using a time lens system. The experimental results are compared with analytical Akhmediev breather solutions showing remarkable agreement, allowing to understand the complex dynamics from an analytical viewpoint. An experimental demonstration of a high dynamic range real-time spectral measurement system for spontaneous modulation instability is also introduced to study the random breather structures in the spectral domain, paving the way for possible indirect optical rogue wave detection schemes.By combining real-time temporal and spectral measurements unforeseen details of transition dynamics of a mode-locking of a fiber laser are also reported. The simultaneous spectro-temporal acquisition allows for complete electric field reconstruction with numerical algorithms, which has not been possible before at megahertz repetition rates with sub-picosecond and sub-nanometer resolutions demonstrated here.Supercontinuum generation is one of the most well-known examples of nonlinear fiber optics that is also becoming widely spread in applications. The details of the complex and noise driven dynamics are now well-known, but the connection of the stability of such light sources with traditional coherence theory was only derived recently. Experimental measurement of supercontinuum stability in the framework of second-order coherence theory is demonstrated, filling a gap in characterization of non-stationary light sources.Finally, an application of supercontinuum generation is proposed in terms of all-optical signal amplification. This is based on the inherently sensitive nature of the nonlinear process to any input fluctuations. The potential of such a highly nonlinear system for a practical application is demonstrated and the underlying dynamics leading to this sensitivity are explained.

The search for sustainable energy sources is one of the greatest problems facing mankind in the 21st century. Most renewable sources do not have adequate potential to cover the growing need for energy in order to sustain economic and population growth. Solar power is a plausible way to fully cover mankind’s continuously growing need for energy. However, sunlight is diurnal, and the amount of sunlight received at different latitudes of the Earth varies drastically. Harnessing solar energy into chemical bonds is an attractive approach to enable the storage of energy for transportation and later use. Direct photoelectrochemical water splitting produces only oxygen and hydrogen, of which hydrogen can be used to sustain a possible hydrogen based economy. The materials used in this Thesis are metal oxide semiconductors that act as photoanodes, performing the water oxidation reaction on their surface and supplying electrons for the water reduction reaction.Hematite is an n-type metal oxide semiconductor that has a band gap suitable for the absorption of a noticeable fraction of solar radiation. The absorption of light leads to the generation of electron-hole pairs that are separated due to a built-in electric field. However, the conduction band level of hematite is not suitable for unassisted water splitting and it suffers from poor intrinsic charge transport properties. For this reason the photoanodes studied in this Thesis have been modified with doping and by forming heterojunctions with other metal oxide semiconductors, namely titanium dioxide.This Thesis studies the evolution of the primary charge carriers responsible for water splitting in modified hematite photoanodes. The method selected to probe the charge carrier dynamics is transient absorption spectroscopy that enables the monitoring of charge carriers from the subpicosecond timescale up to seconds. The measurements were performed in a three electrode photoelectrochemical cell to see the effects of additional bias voltage on the charge carrier dynamics and how the recombination and oxygen evolution reaction are changed when a photocurrent is generated.The results of this Thesis indicate that the modification of hematite has a profound effect on the charge carrier behaviour. The observed effects range from changes in recombination on the picosecond timescale, to nanosecond timescale trapping of electrons into intraband or surface states, and all the way to changes in the reaction rates of long-lived holes in the hundreds of milliseconds timescale.

The transition to the hydrogen economy has been proposed as a sustainable solution for the simultaneous depletion of fossil fuels and the increase in global energy demand since the 1970s. However, the current fossil fuel-based hydrogen production causes significant CO2 emissions. On the other hand, extensive hydrogen production by water electrolysis powered by renewable electricity requires a remarkable increase in the renewable electricity generation capacity. Therefore, alternative solutions are needed in order to promote the hydrogen economy, develop hydrogen infrastructure, and smoothen the transition to the wide-scale renewable-based hydrogen production in the future.In this work, thermal decomposition of methane (TDM) was studied as a transition period solution towards the hydrogen economy. In TDM, methane is converted to hydrogen and solid carbon thereby avoiding the direct CO2 emissions. A laboratory-scale test reactor was designed and constructed in this work in order to experimentally study the TDM reaction. The experimental results were combined with mathematical modeling to find a suitable TDM reaction mechanism for reactor design studies. A global reaction mechanism with reaction parameters optimized in this study was found applicable for this purpose.The TDM product carbon utilization possibilities were evaluated by conducting a market survey. According to the experimental TDM studies in the literature, the product carbon from non-catalytic TDM at temperatures above 1450 K is carbon black. Carbon black is mainly utilized in rubber industry and its market value vary from 500 EUR per tonne to 2,000 EUR per tonne depending on the quality. As a part of the technology development, a design path was outlined to assist the selection of the reaction, reactor, and process parameters for a TDM application. The path was followed in this work when potential industrial-scale technology concepts for hydrogen production by TDM were designed. The economic feasibility of these processes was evaluated and comparison was conducted with two other hydrogen production technologies, i.e., steam methane reforming (SMR) and water electrolysis.According to the economic analysis, a break-even value for the TDM product carbon was found as 310 EUR per tonne of carbon in the current market situation and 280 EUR per tonne of carbon in a potential market situation in 2030 above which the hydrogen production by TDM would be economically feasible in comparison with SMR. The CO2 emissions from the hydrogen production by TDM were considerably lower than in SMR. Electrolysis could provide an economical option for the production of CO2 -free hydrogen when it is powered by inexpensive renewable electricity, but its availability is expected to remain limited in the near future. By contrast, the feedstock availability through the existing natural gas network provides a possibility for demand-driven hydrogen production by TDM. Thus, the most suitable application for TDM was identified in this work as small or medium industrial scale on-site hydrogen production, which minimizes hydrogen transportation costs. The TDM technology implementation could be further advanced by creating a sufficiently large market for the product carbon and tightening the CO2 emission regulation.

Laser pulses are instrumental for a wide range of applications in advanced measurement and imaging techniques, such as time-gated Raman spectroscopy or fluorescent lifetime measurements. Key features for these applications are the relatively high peak power, high pulse energy, and a short pulse duration. To this end, the goal of the thesis has been to demonstrate novel light sources emitting optical pulses with sub-100 ps duration at UV, visible, and infrared wavelengths. The sub-100 ps optical pulse regime fills a gap between the more complex mode-locked lasers and typical Q-switched microchip lasers, which emit optical pulses with duration longer than 300 ps. In particular, key efforts were allocated to developing Nd:YVO4 microchip lasers, emitting either at 1064 nm or 1342 nm, and employing semiconductor saturable absorber mirrors for passive Q-switching. The typical pulse duration was ∼100 ps at 1064 nm and ∼200 ps at 1342 nm. Typical repetition rate was in 100 – 500 kHz range corresponding to average powers of several mW. These laser pulses were amplified in compact Nd:YVO4 amplifiers up to an average power of 1.3 W. Then nonlinear wavelengths conversion techniques were employed to expand the emission wavelength and also to attain further pulse shortening.State-of-the-art results have been achieved on several fronts of research. First of all, in this work the first Q-switched microchip lasers based on GaInNAs semiconductor saturable absorber was developed. Using second harmonic generation, we have achieved leading values for average power, pulse energy, and pulse duration for emission at 671 nm, and 532 nm. Using third harmonic generation we demonstrated emission at 355 nm and using frequency quadrupling we attained emission at 266 nm. Finally, in this work demonstrated the first picosecond diamond Raman laser pumped at 532 nm with sub-100 ps Q-switched pulses. Owing to favorable combination of pulse energy and pulse duration, we attained efficient operation of the Raman laser with emission at yellow (573 nm); the output pulses were as short as 39 ps and the output power was 143 mW, corresponding to a conversion efficiency as high as 40%. In another approach, we demonstrated Raman laser operating at 1240 nm by pumping with 1064 nm Q-switched pulses. In this case, Raman conversion resulted in optical pulses with a duration of 62 ps and 246 mW average power, which were frequency doubled to 620 nm. The corresponding pulse duration and average power at 620 nm were 46 ps and 128 mW, respectively. As third approach, under intense pumping the 620 nm was also generated directly from 532 nm, with 10 mW of average power and 24 ps pulse duration, the shortest pulses achieved in this work.The results open a new perspective to the development of practical laser sources delivering µJ-level short optical pulses. When combined with nonlinear conversion techniques, the technology platform covers an extensive wavelength range and could find uses in a wide range of applications; for example, the 532 nm laser platform has been used successfully in time-gated Raman spectroscopy.

Human urine is an abundant source of the main nutrients (N, P, and K), while in the modern age it may contain traces of pharmaceutical and hormonal compounds. In many parts of the world, urine is collected into sewers, mixed with other wastewaters and treated at centralized wastewater treatment plants. Recently, the source separation of urine has been considered as a way to promote nutrient recovery from households as concentrated streams which could promote its use as fertilizer. The presence of pharmaceuticals and estrogens in urine has raised questions regarding its safe agricultural use, thus leading to a need to monitor the presence of pharmaceutically active compounds in urine. As a minimum, six-month storage before agricultural use is recommended for urine for hygienic reasons. The objective of this thesis was to develop and facilitate the use of source-separated urine by making the characterization of urine easier and faster, to gain more understanding regarding pharmaceutical and estrogenic behavior during urine storage, and to evaluate the suitability of human urine in microalgal cultivations as a nutrient source.An analytical liquid chromatographic method, which had the advantage of simultaneous analysis of eight pharmaceuticals in a short six-minute analysis time, was developed as no such method previously existed (Paper I). The method was validated, proven repeatable, and the obtained pharmaceutical recoveries were acceptable (81.6–109.2%). The limit of detection for the pharmaceuticals in urine was 39–1 610 µg/L. In addition, a previously developed bioluminescent yeast cell biosensor Saccharomyces cerevisiae (BMAEREluc/ERα) was applied on urine samples, as prior to this thesis no information was available on the use of yeast biosensor in estrogenic activity assessment from source-separated human urine (Paper II). The biosensor produced repeatable results in the estrogenic activity testing of fresh and stored human urine with the limit of detection corresponding to 0.28–35 µg/L of estrogens. To enhance the signal, incubation with β-glucuronidase enzyme was used. The biosensor gave a cumulative signal for estrogenic activity (estrogens and estrogen-like compounds), thus enabling the assessment of overall estrogenic activity during urine storage.The method presented in Paper I was subsequently used in monitoring spiked pharmaceutical concentrations in urine during six-month storage (Paper III). Each pharmaceutical (three antivirals and four antibiotic compounds) was tested in laboratory storage both individually and in therapeutic groups, as well as in therapeutic groups either with feces or urease inhibitor amendment. During storage, the overall concentration reductions of 99% were detected, and in assays with amendments, concentrations reductions remained 99%). Four of the pharmaceuticals had reduced concentrations after a sixmonth storage, suggesting biological or chemical degradation and/or precipitation of the compounds.Human urine was tested as nutrient source for biomass production from microalga Chlorella vulgaris (Paper IV). Biomass yield in diluted urine was comparable with growth in artificial growth medium and urine could be utilized up to 1:25-dilutions without inhibition to algal growth. The highest biomass production (0.6 g/L) was achieved in 1:100-diluted urine. C. vulgaris used 32.5–78.7% of N and 35.1–99.0% of P available in urine. At the beginning of cultivation, the majority of the biomass consisted of algal cells, while towards the end the share of living algal cells decreased, indicating accumulation of bacteria and algal cell debris.In conclusion, the results obtained in this thesis indicated that the pharmaceutical concentrations did not reduce enough in order to safely use urine. The yeast biosensor demonstrated that during storage, the estrogenic activity changes most likely due to bacterial enzyme activity, but some activity is still present after five months. The urine is a viable nutrient source for microalgal biomass production, thus having potential for sustainable use and recycling of nutrients.

The main objective of this thesis was to formulate a method with which solid fuel combustion characteristics and physical properties could be accurately com- pared between different samples. The main study instrument used and further developed in the fuel reactivity tests during this work was a laminar drop-tube reactor (DTR). Five different solid fuel sample types were tested with the DTR. The samples were selected to represent a wide range of possible solid fuel types relevant to energy production in Finland. Fossil coal was selected as a reference fuel. Peat was chosen as it is a commonly co-fired with biomass in Finland. The three other samples, raw, torrefied, and steam-exploded woody biomasses, were chosen to find out how thermochemical pretreatment of biomass feedstock affects the fuel combustion characteristics.In addition to the DTR tests, the fine grinding energy requirement of the biomass samples was also examined. Moreover, collaboration work with other researchers was conducted to examine the effect of torrefaction on the fine grinding energy requirement, chlorine content, and heating value. Various domestic and foreign wood species were used in these studies. The torrefaction process was noted to reduce the energy required to fine grind the tested sample. It was also noted that during torrefaction the chlorine content of the solid matter was reduced and the specific heating value was slightly increased. Fine grinding the steam-exploded biomass produced more spherical particles compared to the raw and torrefied pellet samples.The combustion behavior of the five main samples was tested in the DTR. The samples were preground and the particles sieved with vibration sieves with an opening of 100-125 μm. The pyrolysis process was examined separately at a temperature range of 973-1173 K in pure N2. The combined pyrolysis and combustion tests were conducted at a reactor temperature of 1123 K. The O2 concentrations used in the combustion measurements were 3–21 vol-% in either N2 or CO2 atmospheres. The surface temperature of the combusting sample particles was measured with a two-color pyrometer. The initial size distribution of the sample particles as well as their size and geometry evolution as a function of conversion was studied by using optical techniques. The density, specific surface area, and mean pore diameter were measured from the samples with a mercury porosimeter. The reactivity parameters, which describe the pyrolysis and char oxidation rates of the samples, were determined by using the data from the measurements. Using discretized size distribution in the model calculations explained better the measured particle surface temperatures than using a mono sized single particle model. Moreover, combining the optical techniques with the DTR setup provided valuable data on the geometry evolution of the particles.Based on the reactivity parameters, the sample combustion characteristics could be compared with one another. The reactivity comparison method presented in this thesis relies on consistent DTR measurements, determining accurately the size distribution and porosity of the sample particles, and using multiobjective optimization in fitting the model parameters.

We study rainbow connectivity of graphs from the algorithmic and graph-theoretic points of view. The study is divided into three parts. First, we study the complexity of deciding whether a given edge-colored graph is rainbow-connected. That is, we seek to verify whether the graph has a path on which no color repeats between each pair of its vertices. We obtain a comprehensive map of the hardness landscape of the problem. While the problem is NP-complete in general, we identify several structural properties that render the problem tractable. At the same time, we strengthen the known NP-completeness results for the problem. We pinpoint various parameters for which the problem is fixed-parameter tractable, including dichotomy results for popular width parameters, such as treewidth and pathwidth. The study extends to variants of the problem that consider vertex-colored graphs and/or rainbow shortest paths. We also consider upper and lower bounds for exact parameterized algorithms. In particular, we show that when parameterized by the number of colors k, the existence of a rainbow s-t path can be decided in O∗ (2k ) time and polynomial space. For the highly related problem of finding a path on which all the k colors appear, i.e., a colorful path, we explain the modest progress over the last twenty years. Namely, we prove that the existence of an algorithm for finding a colorful path in (2 − ε)k nO(1) time for some ε > 0 disproves the so-called Set Cover Conjecture.Second, we focus on the problem of finding a rainbow coloring. The minimum number of colors for which a graph G is rainbow-connected is known as its rainbow connection number, denoted by rc(G). Likewise, the minimum number of colors required to establish a rainbow shortest path between each pair of vertices in G is known as its strong rainbow connection number, denoted by src(G). We give new hardness results for computing rc(G) and src(G), including their vertex variants. The hardness results exclude polynomial-time algorithms for restricted graph classes and also fast exact exponential-time algorithms (under reasonable complexity assumptions). For positive results, we show that rainbow coloring is tractable for e.g., graphs of bounded treewidth. In addition, we give positive parameterized results for certain variants and relaxations of the problems in which the goal is to save k colors from a trivial upper bound, or to rainbow connect only a certain number of vertex pairs.Third, we take a more graph-theoretic view on rainbow coloring. We observe upper bounds on the rainbow connection numbers in terms of other well-known graph parameters. Furthermore, despite the interest, there have been few results on the strong rainbow connection number of a graph. We give improved bounds and determine exactly the rainbow and strong rainbow connection numbers for some subclasses of chordal graphs. Finally, we pose open problems and conjectures arising from our work.

One of the most important physical properties that defines the behavior of an aerosol particle is its size. Size defines to a great extent how particles behave in physical and chemical processes. Applying experimental and numerical methods, this thesis studies the fundamentals of the operation of impactors, the instruments that are used to measure the size of aerosol particles.The first part of the thesis develops a CFD simulation approach, which is suitable for low pressure impactors and their verification. The CFD model is then used to the study parameters that affect the shape of a low pressure impactor’s collection efficiency curve. The second part focuses on the applications of these findings by introducing two new impactors: a variable nozzle area impactor (VNAI), designed for detailed study of particle behavior in collisions, and a high-resolution low-pressure cascade impactor (HRLPI), used in combination with electrical detection to measure nanoparticle size distribution.Simulations showed that the steepness of the collection efficiency curve depends on the uniformity of the impaction conditions in the impactor jet. Conditions were defined in terms of static pressure, velocity, and particle stopping distance profiles in the cross section of the jet. Uniform impaction conditions and a steep cut-curve were achieved at a short throat, low pressure impactor stage.In the devised VNAI impactor, particles showed very uniform impaction velocities, a fact that was used to examine the critical velocity of the rebound of spherical silver particles. The critical velocities were several orders of magnitude lower than those for micron sized particles. This may be explained by a different material pair used in the experiments and previous studies. The HRLPI was designed based on instrument response simulations to gain maximum information on aerodynamic size distribution and to guarantee robust inversion characteristics in real-time measurement. This was achieved with roughly ten stages per size decade and with slit type, short-throat nozzles.This thesis sheds light on some still unanswered questions in impactor theory and successfully applies the theory to practise by introducing new high resolution impactors for nanoparticle research.

Food waste is a renewable resource that can be utilized as both energy and nutrients through anaerobic digestion to increase nutrient recycling and fertilizer self-sufficiency and promote the mitigation of greenhouse gas emissions. Anaerobic digestion of food wastes has, however, faced challenges due to the waste’s characteristics, e.g., high protein content, which is why the organic loading rates with food waste digestion are usually kept low to achieve a stable process. The digestate produced during digestion contains all of the nutrients from the food waste feedstock and can be used as a fertilizer in agriculture, where the availability of nutrients, the stability of organic matter, and biosecurity define its agronomic value. In this thesis, the aim was to analyze the potential of using anaerobic digestion for food waste utilization. The anaerobic digestion of food waste, feedstock pretreatment, and processing and utilization of the digestate for fertilizer use were studied.This study shows the potential of food waste as feedstock for anaerobic digestion without dilution, with a total solids content of 20–25%. A high organic loading rate of 6 kgVS/m3d (VS, volatile solids) was achieved with methane yields 400–430 m3/kgVS in continuous food waste digestion while the optimum loading rate was 3 kgVS/m3d, yielding around 480 m3/kgVS of methane. Trace element supplementation enabled a stable long-term operation and gradual increase of loading rates without the accumulation of acids. The autoclave pretreatment (160°C and 6.2 bars) of the food waste affected the characteristics – and subsequently, the anaerobic digestion performance, where the formation of protein-based hardly biodegradable compounds led to a 10% lower methane yield during digestion, decreased hydrogen sulfide content in the biogas, and 50% decreased ammonium nitrogen concentration within the digestate. The decreased availability of proteins and hydrogen sulfide formation due to the pretreatment reduce the risk of ammonia inhibition during anaerobic digestion and enable easier biogas cleaning and security.The food waste digestates shows potential as a nutrient source in crop fertilization independently and after post-treatment. The studied digestates were considered suitable for fertilizer use, as they showed good agronomic value in terms of nutrient content and usability, as well as biosecurity. Food waste digestates produced around 5 to 30% higher ryegrass yield compared with a mineral fertilizer in pot experiments, and the majority (50–70%) of the nitrogen and phosphorus were in the soluble and plantavailable forms. The integration of anaerobic digestion and digestate post-treatment technologies enabled the processing of the digestate liquid into concentrated nutrient products rich in nitrogen and potassium. With the combination different processing technologies such as evaporation, stripping, and reverse osmosis, nutrient products with optimal composition can be produced to correspond with the fertilizer demand. Overall, due to the high energy potential of the food waste, the integration of the anaerobic digestion with heat-demanding digestate liquid post-treatment processes (e.g., stripping and/or evaporation) was possible.In conclusion, anaerobic digestion has high potential for the utilization of food waste, as food waste produces high methane yields in optimized conditions. The food waste digestate was also shown to be a suitable nutrient (especially nitrogen) source in crop fertilization independently and after posttreatment.

In recent decades, microalgae have attracted attention as a promising biomass source for a variety of different biofuels, including methane via anaerobic digestion (AD). However, the energy intensity and cost (e.g., for the nutrient supply) of the process chain mean that breakthroughs in algal biofuels have yet to be realized. The objective of this study was to improve the AD of wastewater-grown microalgal biomass, marine algal residues following lipid extraction for renewable diesel production and to improve the AD of pulp and paper industry biosludge. The digestate from the latter substrate could provide nutrients for algae cultivation and lipid extraction followed by AD offers the possibility of obtaining multiple products from algal biomass, as envisaged by the algal biorefinery concept.Based on the results of this experimental work, pretreatments and novel reactor designs can be used to improve the AD of microalgae. In this study, BMPs for wastewater- and digestate-grown mixed populations of microalgae varied between 154 and 273 L CH4 kg– 1 volatile solids (VS). Low-temperature (3 h, 80°C) pretreatments enhanced the BMPs by 11–27%. However, to ensure positive energy balances, the availability of waste heat was necessary. Due to longer solid retention times, the AD of microalgae in unmixed, accumulating-volume reactors (AVRs) at 16–21° C was more feasible than AD in conventional completely stirred tank reactors (CSTRs) at 35°C when the solid concentration of the algal biomass was low (< 4% total solids [TSs]). Biological (at ~60°C) and freeze-thaw pretreatments enhanced the methane yield (32–50% increase) and the mineralization of nitrogen and phosphorus (41–84% increase) in the low-temperature AVRs.In the present study, the AD of marine algae residue after lipids were extracted for renewable diesel production was demonstrated and the salt concentration of the marine algal biomass did not affect AD. Thermophilic AD in the CSTR resulted in a 48% higher methane yield (220 L CH4 kg–1 VSs) of algal residues compared with mesophilic AD. However, unlike mesophilic AD, ammonia, which originated from the high nitrogen content of the algal biomass, inhibited the thermophilic process.AD of pulp and paper industry biosludge mineralized nutrients to a soluble form, making effluent a potential media for algal cultivation. The methane yield from the biosludge was low (78 L CH4 kg–1 VS) but increased by 77% with thermal pretreatment (20 min, 121°C). The pretreatment also resulted in AD with a retention time of 10 d, as compared to 14 d for untreated biosludge. However, the energy balance of the pretreatment was dependent on the solid concentration and temperature of the biosludge from the industrial process.To conclude, this work demonstrated AD of microalgae under psychrophilic, mesophilic, and thermophilic conditions. The low energy balances emphasize that improvements in algae cultivation are required and/or other benefits (e.g., nutrient recovery, value-added products, and waste treatment) obtained for algal AD to become a full-scale application.

More often than ever before, innovation activities are crossing organizational boundaries and taking place in the spaces between formal, organizational structures. This new context for innovation activities is increasingly referred to as an innovation ecosystem. Open innovation, co-creation, user-driven innovation, API and platform economies, and business ecosystems are key drivers of the transformation. Innovation ecosystems are open, dynamic systems that cross geographical as well as organizational boundaries and include financial, technological, and political dimensions. Talented humans have a crucial driving role in ecosystemic innovation activities. Innovation ecosystems set a new framework for analyzing, investigating, and therefore measuring innovation.Measuring and visualizing innovation is difficult, particularly within innovation ecosystems where activities take very complex forms and even identifying all relevant actors and stakeholders is challenging. At the same time, ecosystem-level analyses of innovation ecosystem structures are imperative for three groups: innovation ecosystem scholars, policy and decision makers, and innovation ecosystem actors. Moreover, new sources of digital data on innovation activities have become available, introducing new opportunities to investigate innovation ecosystems at the ecosystem level.In this dissertation, we seek to develop new means to utilize digital data in analyzing innovation ecosystems at the ecosystem level. We take an action design research approach to develop the means to investigate the structural properties of innovation ecosystems at the ecosystem level by using visual network analytics. We start from the realization that interconnectedness is a key property of innovation ecosystems. Addressing innovation ecosystems as networks, that is, as collections of pairs of interconnected innovation ecosystem actors, allows scholars and practitioners to gain insight into innovation ecosystem structures and the structural roles of individual ecosystem actors. To determine how innovation ecosystems should be modeled and analyzed as networks, we investigate several innovation ecosystems representing regional, metropolitan, national, and international contexts as well as investigating the context of programmatic activities that support innovation and growth. Our main objective in the dissertation is to develop a process model for data-driven visual network analytics of innovation ecosystems.Visual network analytics is a valuable method for investigating and mapping the innovation ecosystem structure. In the proposed approach, transactional microdata on innovation ecosystem actors and their interconnections is collected from various digital sources. Innovation ecosystem actors are represented as network nodes that are connected through transactions, including investments and acquisitions and advisory, founder, and contributor affiliations. Network metrics are used to quantify actors’ structural positions. Interactive visual analytics tools are used to support the visual exploration of the innovation ecosystem under investigation by using both top-down and bottom-up strategies.This work makes several contributions to the art and science of data-driven visual network analytics of innovation ecosystems. Most importantly, the dissertation proposes the ostinato model, an iterative, user-centric, process-automated model for data-driven visual network analytics. The ostinato model simultaneously supports the automation of the process and enables interactive and transparent exploration. The model has two phases: data collection and refinement, and network creation and analysis. The data collection and refinement phase is further divided into entity index creation, Web/API crawling, scraping, and data aggregation. The network construction and analysis phase is composed of filtering in entities, node and edge creation, metrics calculation, node and edge filtering, entity index refinement, layout processing, and visual properties configuration. The cycle of exploration and automation characterizes the model and is embedded in each phase.In addition to the ostinato model, we contribute a set of design guidelines for modeling and visualizing innovation ecosystems as networks. Finally, we contribute to the empirical body of knowledge on innovation ecosystems through a series of investigations of innovation ecosystems of different levels of abstraction and complexity. Innovation ecosystem scholars, policy makers, orchestrators, and other stakeholders in the innovation ecosystem under investigation in this dissertation have subscribed to the approach presented herein. The design guidelines, together with the ostinato model, allow innovation ecosystem investigators and actors an opportunity to significantly advance in utilizing visual network analytics in managing and orchestrating innovation ecosystems. Further research and development of supporting processes and tools are needed to take full advantage of the presented approach in analyzing, investigating, facilitating, and orchestrating interorganizational innovation activities.

The municipalities of Finland are facing interesting times; the public sector as a whole is struggling with economic and productivity challenges and is striving to find innovative development strategies for the future. The prevailing conditions are reflected in the built environment, in the technical sector of municipalities and, therefore, in infrastructure services such as water services. Generally speaking, water services are perceived to be static in nature that have operated successfully in the relatively unchanging conditions of history. However, the increasing complexity and faster rate of change in the operating environment are forcing water services to be more innovative and able to explore their own role as a part of variety of systems as well as to formulate problems accordingly. The way water services are thought and seen ultimately defines what kind of solutions are produced and services delivered. Thinking patterns related to water services shape its future.These thinking patterns – the paradigms of water services – are in the spotlight in this doctoral dissertation. For this purpose, the conceptual framework of two alternative paradigms of water services is constructed. Paradigm 1 represents a production-oriented world view that rests on reductionist thinking, production-based value creation logic, and closed-context expertise. Paradigm 2 embodies a service-oriented world view that is based on holistic systems thinking, service-based value creation logic, and open-context expertise. Based on this conceptual framework, the four selected research articles are explored, following the principles of qualitative research. The purpose is to find and clarify the paradigm related clues of the articles, and hence approach the question: how are water services thought?The theme of the first article relates to the relationships between water utilities and external service providers. It shows that the relationships are based on mistrust that must be managed by continuously tightening contracts. As a consequence of the dominant paradigm, there is no foothold left for building trust between parties. The second article highlights the identity of water services by asking what kind of meanings water utilities place on water services. Reflecting the findings in relation to the paradigms, it is seen that the aim of water services is perceived to be the realization of top-down imposed goals. This explains why sense-making with wider systemic meanings hardly occurs. The theme of the third article relates to the idea of inverse infrastructure, which refers to user[IV] driven developed infrastructures that have the characteristics of self-organization and volunteerism. These kinds of alternative infrastructure solutions shift the power of decision away from formal systems, hence this tendency is not necessarily favoured in the municipal infrastructure policy. In the light of paradigm exploration, municipal infrastructure policy should be enabling and integrative. The theme of the fourth article, in turn, deals with social norms. It is argued that following social norms over sectoral boundaries has an effect on trust and acceptance towards the water services.Regarding all four articles, this study revealed that, along with material and quantitative dimensions, there resides invisible system dimensions affecting the service that is ultimately provided. If water services are perceived by a production-oriented paradigm, these less obvious system dimensions are ignored or formulated in an inappropriate manner. A service-oriented paradigm is, in turn, more responsive to different system dimensions; it also emphasizes that the less obvious phenomena can have an influence on the service as a whole. From the research that has been carried out, it can be concluded that if the purpose of water services is to create well-being for the wider society, then there seems to be a need for a paradigm shift that puts more consideration on the changing and ever more complex operating environment. In that case, the ways water services are thought and understood have to change towards a world view outlined by the serviceoriented paradigm. It helps to rediscover the linkage between the water services and societal development. Suomen kuntakentällä eletään tällä hetkellä mielenkiintoisia aikoja julkisen sektorin kamppaillessa talous- ja tuottavuusongelmien kukistamiseksi ja pyrkiessä löytämään innovatiivisia tulevaisuuden kehityssuuntia. Olosuhteet heijastelevat myös rakennettuun ympäristöön, kuntien tekniseen toimeen ja siten myös vesihuollon kaltaisiin infrastruktuuripalveluihin. Vesihuoltoa voidaan pitää luonteeltaan varsin staattisena alana, joka on historiansa aikana toiminut menestyksekkäästi suhteellisen vakaissa olosuhteissa. Nyt toimintaympäristön kompleksisuus, muutosnopeus ja muut paineet lienevät suurempia kuin koskaan aiemmin. Sen myötä tulee aiheelliseksi ottaa tarkasteluun vesihuollon uudistumiskykyyn liittyviä kysymyksiä ja pohtia vesihuollon olemusta erilaisten systeemien osana. Toisin sanoen vesihuollon hallinnassa tulee yhä ajankohtaisemmaksi ja oleellisemmaksi hahmotella palvelun systeemistä merkitystä ja muotoilla ongelmia tähän nähden tarkoituksenmukaisilla tavoilla. Se, miten vesihuoltoa ajatellaan ja millaisena vesihuolto nähdään, määrittää tuotettavien ratkaisujen ja vaikutusten kirjoa. Vesihuoltoon liitettävät ajatusrakenteet luovat sen tulevaisuutta.Tässä tutkimuksessa pureudutaan juuri näihin ajatusrakenteisiin – vesihuollon hallinnan paradigmaan. Tätä tarkoitusta varten tutkimuksessa luodaan kahden vaihtoehtoisen paradigman muodostama käsitteellinen kehys. Paradigma 1 edustaa tuotantoorientoitunutta maailmankuvaa, joka tukeutuu reduktionistiseen ajatteluun, tuotantokeskeiseen arvonluontilogiikkaan ja suljettuun asiantuntijuuteen. Paradigma 2 puolestaan ilmentää palveluorientoitunutta maailmankuvaa, joka nojautuu systeemiseen ajatteluun, palvelukeskeiseen arvonluontilogiikkaan ja avoimeen asiantuntijuuteen. Tämän käsitteellisen kehyksen avulla tarkastellaan neljää tutkimusaineistoksi valittua tieteellistä artikkelia. Tehtävä toteutetaan laadullista tutkimusotetta seuraten. Tarkoituksena on löytää ja kirkastaa artikkeleissa piileviä vesihuollon hallinnan paradigmaan viittaavia johtolankoja. Tätä kautta lähestytään kysymystä: miten vesihuoltoa ajatellaan?Ensimmäisen tutkimusartikkelin tematiikka liittyy vesihuoltolaitosten ja palveluntarjoajien välisiin suhteisiin ulkoistamishankkeissa. Havaitaan, että suhde nojautuu epäluottamukseen, jota pyritään hallitsemaan sopimuskovuuden keinoin.Vallitsevan paradigman johdosta luottamuksen ja syvemmän kumppanuuden rakentamiselle ei tällöin jää jalansijaa. Toinen artikkeli nostaa esille vesihuollon identiteetin kysyessään, millaisia merkityksiä vesihuoltolaitokset alan keskeisimpinä [II] toimijoina itse vesihuollosta rakentavat. Paradigmatarkastelussa huomataan, että vesihuollon toimenkuvaksi nähdään ylhäältäpäin asetettujen tavoitteiden toteuttaminen, mikä selittää sitä, miksi toimintaa ei kytketä sen laajempiin merkitysyhteyksiin. Kolmannen artikkelin teema liittyy käänteisen infrastruktuurin ideaan, joka nojaa paikallisyhteisöjen omaehtoisuuteen, itseorganisoituvuuteen ja vapaaehtoisponnisteluihin infrastruktuuripalvelujen tuottamisessa. Tällaiset vaihtoehtoiset infrastruktuuriratkaisut vievät päätösvaltaa virallisten järjestelmien ulkopuolelle, joten kehityssuunnan hyväksyminen ei ole itsestäänselvyys kunnallisessa infrastruktuuripolitiikassa. Paradigmatarkastelu vahvistaa käsitystä siitä, että kunnallisen infrastruktuuripolitiikan tulisi olla luonteeltaan mahdollistavaa ja integroivaa. Neljännen artikkelin aihepiiri liittyy puolestaan sosiaalisten normien maailmaan. Havaitaan, että sosiaalisten normien noudattamisella on alakohtaiset sektorirajat ylittäviä vaikutuksia suhteessa palveluun kohdistuvaan luottamukseen ja hyväksyntään.Paradigmatarkastelu paljasti jokaisen artikkelin tematiikkaan liittyen, että materiaalisten ja mitattavien ulottuvuuksien ohella vesihuollossa vaikuttaa myös näkymättömämpiä systeemidimensioita, joilla on olennaista merkitystä siihen palveluun, jota vesihuollon kautta kaiken kaikkiaan tuotetaan. Jos vesihuollon hallintaa ajatellaan tuotantoorientoitunutta paradigmaa mukaillen, nämä vähemmän ilmeiset systeemidimensiot sivuutetaan tai muotoillaan niiden luonteeseen nähden epätarkoituksenmukaisesti. Palveluorientoitunut paradigma on puolestaan herkkä myös tällaisille vähemmän ilmeisille systeemiulottuvuuksille, joissa palvelun inhimilliset ja kokemukselliset piirteet saavat jalansijaa. Paradigmatarkasteluun perustuen voidaan sanoa, että jos vesihuollon tarkoitus liittyy siihen, kuinka se oman toimenkuvansa kautta saa aikaan hyvinvointia ympärilleen ja onnistuu osallistumaan arvon yhteisluonnin prosesseihin, on dynaamisessa ja kompleksisessa toimintaympäristössä tarve paradigman muutokselle. Vesihuoltoon liittyvää ajattelua ja tietämistä on tarpeen muuttaa kohti palveluorientoituneen paradigman hahmottelemaa maailmankuvaa. Sen myötä voidaan uudella tavalla löytää vesihuollon kytkeytyneisyys yhteiskunnalliseen kehitykseen.

The thesis deals with the investigation of optical, electrical and structural properties of III-V semiconductor materials and nanostructures with applications in the development of next generation solar cells. In particular, the focus is on the study of quantum well (QW) and quantum dot (QD) nanostructures, and dilute nitride materials. Nanostructures can improve solar cell performance by, e.g., extending the absorption edge, providing an intermediate band, or suppressing reflection at the solar cell surface. Dilute nitrides, on the other hand, can provide better utilization of the solar spectrum, thus increasing the conversion efficiency of multijunction solar cells. The interplay between fabrication parameters as well as post growth treatments of the investigated structures, and their optical and electrical properties, are assessed by several characterization methods, including photoluminescence and capacitance spectroscopy. The results show that small changes in these parameters can have a significant influence on the defect populations and overall properties of the heterostructure, eventually defining the solar cell performance.Starting from the outer layer of the solar cell device, the surface structure was found to play an important role in connection with thermal annealing. Short chemical treatments modifying the GaAs surface had a huge influence on optical and structural properties of the studied QWs upon annealing. Furthermore, ammonium sulfide treatment of the solar cell AlInP window layer was found to modify the surface structure and improve the solar cell performance. Optimization of the amount of deposited InAs and use of the so-called “flushing technique” was found to remove unwanted defects in QD layers. For the GaSb QD heterostructures, the influence of material fluxes during the growth, thermal annealing, and stacking of QD layers on optical and solar cell properties was studied. Dilute nitride QWs, acting as strain compensation and mediation layers for QD layers, were found to extend the absorption edge in the solar cell structure, and provide steps for charge carriers to thermally escape from the QD layer. Stacked strain free GaAs QD nanostructures, fabricated by refilling of self-assembled nanoholes, were found to emit photoluminescence related to several quantum dot states with narrow linewidths. The investigated GaAs QDs were also extremely temperature stable upon high temperature thermal annealing, indicating low defect densities. The formation of defects in bulk dilute nitride solar cells and their relation to process parameters on the one hand, and solar cell properties on the other hand, was also studied; optimal fabrication conditions were then devised. Incorporation of Sb was found to decrease the background doping density but at the same time broaden the deep level transient spectroscopy spectra. Furthermore, the As flux used during the fabrication of the dilute nitride solar cell was found to have a remarkable influence on solar cell performance.

Laser-induced breakdown spectroscopy (LIBS) is a selective and robust atomic emission spectroscopy method where a high intensity laser pulse thermally dissociates and excites a minute quantity of the sample material. In LIBS, all elements can be measured simultaneously which makes it useful in applications where fast multicomponent analysis is required. Trace element analysis technology based on LIBS was developed in this Thesis for monitoring of dissolved impurities in water. The concentrations of dissolved elements in industrial process water and effluent are measured for process steering and for emission management. At the moment, the chemical analysis of water is mainly done by manual sampling and laboratory analysis. Online measurement technology would contribute to the economical use of water, chemicals and energy in the process industry and further the safety of liquid emissions.Two novel methods for improving the sensitivity of LIBS of dissolved elements were introduced in this Thesis. In the presented techniques, aerosol particles generated from the sample solution are analyzed individually with LIBS. The main benefits of single particle LIBS are the high preconcentration of the sample and the absence of the liquid matrix which suppresses the LIBS signal. In the first instrumentation, the particle travels along a narrow carrier gas flow and its presence in the small sampling volume is determined by an optical sensor. In the second presented technique, the generated droplet is trapped in three dimensions using electrodynamic balance (EDB) technology and the residual particle is analyzed after the complete drying of the droplet. A detailed characterization of LIBS of precisely trapped particles was also conducted in this Thesis. Clear improvement with respect to reproducibility and sensitivity was achieved in this work compared with the direct LIBS analysis of water. The limits of detection for the constructed EDB-LIBS system were at 50 µg/l level for several transition metals and are among the lowest values obtained with LIBS based trace element analysis. The flexible requirements for the LIBS laser pulse energy and the speed of operation improve the applicability of the aerosol based sample preparation to the monitoring of industrial and natural waters. Moreover, the concurrent detection of dissolved elements and microbiological contamination of water was demonstrated by the combination of laser-induced fluorescence and single particle LIBS.

Alpha radiation presents a challenge for operators in the field of nuclear safety and security. Due to the short range (few centimeters in air) and high stopping power, alpha particles are conventionally detected with dedicated instruments in close proximity of the source. However, the thermalization of an alpha particle in air causes an effect similar to northern lights. The scale of this radioluminescence emission is very weak, but the increase in range and number of signal carriers allows remote detection of alpha particles. This Thesis investigates the light yield of this effect and its applications to alpha radiation detection.An experimental approach is taken to estimate the amount of radioluminescence photons per single alpha particle. Two different methods are employed for the measurement and the result of 19 ± 3 photons/MeV is discussed in the light of previous works. In addition, the emission spectrum is recorded in order to support the observations. This knowledge is essential for quantitative performance estimations of the method.Contamination screening at distances greatly exceeding the typical range of alpha particles is studied by two-fold approach. First, three types of scientific-grade cameras are used to image radioluminescence light of alpha radiation sources at a nuclear research facility. The images are taken through translucent materials in darkness, and the feasibility implications of this fieldwork are described. Second, the translation into operative use is facilitated by development of a remote mapping system, optimized for use in an illuminated environment. The system is based on single pixel detector with a telescope that is panned across an area of interest. The process is automated in order to demonstrate its potential in nuclear decommissioning applications.Whilst the radioluminescence method enables remote mapping of alpha sources, further analysis of the emitters requires gamma spectrometry. Here, the optical signals of alpha particles are used to trigger a gamma measurement of materials which decay via simultaneous emission of an alpha particle and a gamma ray. This allows focusing of gamma measurement without collimators and provides an effective means to reduce background level for the detection of minute amounts of material.The coincidence method is also applied to direct detection of radon decay in air by observing simultaneous photon detection events. For the demonstration, high speed electronics are employed for list mode collection of radon events. The results are carefully analyzed to maximize the potential of large measurement volume and the temporal response of the method. The developed detection system is benchmarked and calibrated against a leading commercial radon detector.Overall, the results confirm that radioluminescence light can be successfully utilized for in situ detection and characterization of alpha radiation sources. Moreover, the method allows unprecedented approaches that may establish their niche in the coming years.

Photoinduced processes in hybrid semiconductor-organic nanostructures were studied in this thesis. The work was divided into three tasks: (1) preparation of ZnO thin films and nanorod arrays in a controlled and cost-effective way, (2) functionalization of the ZnO surfaces with organic, photoactive layers and (3) study of photoinduced reactions on the surfaces by both steady state and time-resolved methods. Aluminum doped zinc oxide (AZO) electrodes were tested as an alternative for the traditionally used indium tin oxide semitransparent electrodes in organic solar cell devices.The electrodes were prepared by atomic layer deposition method. Devices with AZO electrodes showed performance comparable to that of the reference device but were more stable in open air showing no degradation during 40 days time interval. ZnO nanorod arrays were prepared and used as model substrates to study electronic interactions at semiconductor-organic interface. The growth was optimized to achieve well-aligned nanorods with high specific surface area. To control the semiconductor electronic properties, while keeping the morphology unchanged, the nanorods were further modified with thin layers of Al2O3 or TiO2 prepared by atomic layer deposition. Self-assembled monolayers (SAM) of three different porphyrin derivatives and one phthalocyanine derivative were formed on the ZnO nanorods using carboxylic acid or siloxane as anchor groups. The fastest electron transfer from zinc porphyrin (ZnP) to the semiconductor was observed for the ZnO nanorods modified with a 5 nm layer of TiO2 ( 5 ns) chargeseparated states are formed. In these states electrons are localized in ZnO and the holes in the organic donor layer, while ZnPc is in the ground state.

Groundwater is an invaluable part of our natural, built, and socio-economic environments. In global context, groundwater is the largest freshwater resource: almost half of all drinking water is abstracted from underground. During the last few decades, Finnish community water supply has increasingly relied on natural and artificially recharged groundwater as raw water source. Currently, their combined share of the water supplied is some 66 percent, out of which 16 percent is artificially recharged. However, potential groundwater areas and places for groundwater recharge are sparsely situated. Thus, large city centres, with their increasing need for fresh water supply, are obliged to withdraw groundwater from afar, often crossing municipal borders. This may cause tensions between different jurisdictional units; generally, between rural and urban areas. This research illustrates how cooperation between municipalities can turn into a conflict. Indeed, there are several examples of local conflicts around the inter-municipal groundwater projects in Finland. Many projects which are justified on both technical and economic grounds have problems in gaining legitimacy among local inhabitants. Oppositions emerge and projects may go through long litigation processes.A contentious groundwater project can be classified as a complex management problem: it is unpredictable, uncontrollable, and it has several, often contradictory interpretations. Therefore, conventional groundwater management approaches, drawing from expert-based instrumental rationality, often are insufficient for successful project planning and implementation. Indeed, the emerging paradigm emphasizes collaborative approaches to complex management problems in the fields of natural resources management as well as urban planning. Water services (water supply, wastewater treatment, and storm water management) are inherently bound to these fields through their multiple connections with aquatic environment, required technical infrastructures, and influence on socio-economic development.The main objective of this study was to find new perspectives for groundwater governance by analysing contentious cases that operate in field of water services, thus connecting the contexts of natural resources management and urban planning. Accordingly, the research problem was formulated as follows: Which are the major constraints in large scale groundwater projects from the perspective of collaborative governance, and what lessons can be drawn for future collaboration?The research problem was addressed through negotiation theory and discursive framework which adhere to social constructionist tradition. Through these theoretical and methodological considerations, this study enclosed conflict analysis and discourse analysis. These methods were exploited in a comprehensive analysis of the two case studies where inter-municipal water supply projects, based on the managed aquifer recharge (MAR) technology, were contested by local inhabitants. First case is situated to southwestern coastal area of Turku Region. It started already in the 1970s as a long-distance water transfer project, and was finalized in 2010 when an MAR plant started to operate on the esker of Virttaankangas. However, the other case, situated to Tampere Region, started in 1993, and the process is still unfinished.The results of this study indicate that the water management sector is strongly grounded on instrumental rationality when solely expert knowledge is considered as a legitimate source of information. Accordingly, planning and management of the MAR projects concentrated mainly on the visible tip of an iceberg, instead of managing the whole. The interaction between parties was based on competitive mindset and zero-sum game; thus, the underlying interests and the complexity of the project were not recognized. Strong positions were taken, which precluded the possibility of finding mutual gains.Although cases involved some collaborative efforts, they were used only as casual tools without really relying on collaborative rationality. However, in groundwater governance it should be other way round: the core should be in collaborative rationality while some of the tools can be obtained from rationalistic expert-based planning. Thus, legitimacy for the project should be gained through joint knowledge production as well as interaction, where addressing stakeholders’ interests instead of predefined goals could help in finding mutual gains and creative new options for collaboration. Furthermore, in this process, water managers and experts should be more like facilitators than holders of the only legitimate source of knowledge and the stakeholders like partners rather than informants or adversaries.

Ligand-protected nanoclusters (NCs), such as thiolate-protected gold NCs, have been of great interest for the nanoscience community because of their unique properties that can be realized in practical applications. This class of nanomaterials has interesting physical properties where a cluster can behave as if it was a single atomic-like entity. This unique feature is due to the delocalized electrons in clusters, in connection with the superatom model concept.This thesis aims to address the applicability of the superatom model in different contexts for ligand-protected NCs. We employ density functional theory simulations to understand how the physical factors, such as structural modification, can affect the underlying superatomic characters of clusters. The first part of this thesis investigates two closely related gold NCs having the same biicosahedral motif for their cores (Au24 and Au25 cores), where they differ by a single gold atom only. Each icosahedron of the Au25 cluster represents a superatom, and this is a di-superatomic NC. Our analysis suggests that the absence of the central gold atom (the vertex-sharing atom in Au25 core) in the Au24 cluster does not modify the di-superatomic feature provided that they exhibit the same numbers of delocalized electrons.The second part of this thesis studies a different class of clusters: ligand-protected silver sulfide NCs which have both metal and non-metal core atoms. Despite having core sulfur atoms that localize the delocalized electrons from silver atoms, silver sulfide NCs have superatomic states manifested in their conduction bands. Our analysis indicates that it is essential to have a predominant weight of Ag atoms in the core to generate superatomic features in silver sulfide NCs.A further study on a silver sulfide NC with delocalized electrons, [Ag62S12(StBu)32]2+ cluster, demonstrates new insights for the role of core sulfur atoms. Superatomic state can exist in the valence band of the nanocluster, though the ordering of superatomic states differs from those predicted by the superatom model. This phenomenon can be ascribed to the localization of some (nominally) delocalized electrons induced by the core sulfur atoms.Finally, we revisit the di-superatomic NCs and investigate their structural changes induced by electrooxidation. The delocalized electron counts of Au38(SC2H4Ph)24 and [Au25(PPh3)10(SC2H4Ph)5Cl2]2+ suggest that they are analogies of the di-atomic molecues F2 and Ne2. Upon electrooxidation, the core structure of the Au38 cluster remains stable, while the core structure of Au25 undergoes an irreversible change. The experimental and simulation results suggest that the redox behaviors of these NCs cannot be simply predicted based on the simple bonding scheme as suggested by the interaction of superatomic units. In contrast to the di-atomic molecules, structural factor needs to be considered in understanding the redox behaviors of di-superatomic NCs.

In this thesis we develop methods for recovering the three-dimensional shape of an object from generalized projections. We particularly focus on the problems encountered when data are presented as discrete image fields. We demonstrate the usefulness of the Fourier transform in transferring the image data and shape model projections to a domain more suitable for gradient based optimization. To substantiate the general applicability of our methods to observational astronomy, we reconstruct shape models for several asteroids observed with adaptive optics, thermal infrared interferometry, or range-Doppler radar. The reconstructions are carried out with the ADAM software package that we have designed for general use.

In the last two decades, fluorescent proteins have become one of the most widely studied and exploited protein in biochemistry and cell biology. Fluorescent protein is a protein that upon excitation at low wavelength light emits fluorescence at higher wavelength. Its ability to generate high intracellular visibility together with the stable internal fluorophore and non-invasive measurement technologies made it the finest tool to monitor cellular processes and molecular events in living cells at its normal physiological conditions. Protein engineering and identification of novel fluorescent proteins have resulted in the development of color variants ranging from the blue to near-infrared region of the spectrum. Protein engineering has also lead to the development of highly stable fluorescent proteins with improved photochemical properties and sensing abilities.The fluorescent proteins have made a strong impact in cell biology research due to its ability to participate in energy transfer interactions, such as Fluorescence resonance energy transfer (FRET) and thus allowing to measure and study molecular-scale distances and dynamics through changes in fluorescence. Development of novel FRET based techniques, FRET sensors and FRET pairs will provide opportunity to understand the cellular processes and dynamics with high precision at nano-scale level. This thesis focusses on FRET studies by developing novel FRET based sensor, novel FRET pairs and analyzing intramolecular FRET. The study also focuses on analyzing the potential of fluorescent proteins in sensing applications outside the cell environment, an area which has not yet been exploited. This was accomplished by protein engineering of fluorescent proteins with specific objectives followed by steady-state and time-resolved fluorescence spectroscopy measurements.In one of the specific objective, intramolecular FRET in fluorescent proteins was studied by demonstrating FRET between fluorescent protein and conjugated chemical fluorophores whereby FRET occurs from inside to outside of the protein and vice versa. For this study, novel FRET pairs MDCC−Citrine and Citrine− Alexafluor 568 was generated. FRET analyzed using steady-state and ultra-fast time-resolved spectroscopy measurements revealed strong intramolecular FRET with high efficiencies. To my knowledge, this is the first and only study on bidirectional FRET between fluorescent protein and conjugated chemical labels. This study was made possible by genetically engineering Citrine to incorporate cysteine residues on the surface of the protein and this enabled site-specific bioconjugation of the labels to the fluorescent protein.The surface exposed cysteine on the fluorescent protein was also exploited in this study to generate self-assembled monolayer (SAM) of Citrine on the surface of etched optical fibers (EOF). The conjugation of Citrine to the surface of EOF demonstrated a proof-of-concept for the use of this bio-conjugated protein in in vitro bio-sensing applications. To the best of our knowledge, this is the first and only study on the formation of fluorescent protein SAM on EOF. Steady-state and fluorescence lifetime measurements confirm the formation of SAM on EOF and revealed that the bioconjugation is site-specific and covalent in nature. The study also demonstrates that the proteins retains its photochemical properties on bioconjugation and are stable at physiological conditions.The engineered surface exposed cysteine was further used in this study for the development of a FRET based redox sensor. This was developed aiming to overcome the disadvantages of the current FRET based redox sensors which includes low FRET efficiency and dynamic range, and to monitor the redox status in bacteria. For the sensor development, fluorescent proteins Citrine and Cerulean were genetically engineered to expose reactive cysteine residues on the protein surface. The proteins were fused using a biotinylation domain as a linker to generate the FRET sensor. The redox titrations and the fluorescence measurements confirmed the redox response and reversibility of the sensor. The FRET sensor exhibited high FRET efficiency and dynamic range in intensity based measurements. Intracellular studies with Escherichia coli revealed the capability of the FRET sensor in detecting real-time redox variations at single cell level.In the final study, novel FRET pairs were developed aiming at improved fluorescence lifetime dynamic range and high FRET efficiency for the use in fluorescence lifetime imaging microscopy (FLIM) studies. The fluorescent protein with the longest reported fluorescence lifetime NowGFP was used as a FRET donor and various red-fluorescent protein variants were screened for the optimal FRET acceptor. Among the FRET pairs screened, NowGFP-tdTomato and NowGFP-mRuby2 were found to be superior FRET pairs with high lifetime dynamic range and FRET efficiency. NowGFP-tdTomato pair was found to have the highest reported Förster radius and fluorescence lifetime dynamic range for any fluorescent protein based FRET pairs yet used in biological studies.In summary, we have developed novel FRET based tools and in vitro techniques using fluorescent proteins which can assist in deepening the knowledge on intracellular environment and dynamics, and also in developing novel fluorescent protein based sensors which can be used outside the cellular environment.

Large aromatic chromophores, e.g. phthalocyanines or perylene derivatives are widely used in modern photonic applications. For these systems, well-organized films of the chromophores are very important. One of the ways to ensure the order on molecular level is to bind the organic dyes covalently to a solid substrate with a suitable anchor group. Expanding the concept, multilayered supramolecular assemblies can be built on surfaces as well.In the present Thesis various chromophores with a capability to anchor onto a solid surface were prepared. Synthesized molecules were porphyrins, phthalocyanines, and perylene mono- and diimides with different substituents. The anchor-surface pairs were of several types, and the chromophores were attached to a surface by one- or two-step methods.Two of the perylene monoimide derivatives were found to be a perfect basement for construction of multilayered films. Using a metal-ligand interaction it was possible to prepare stable double layers, as well ten molecules thick stable deeply colored multilayer films. The developed approach is versatile and will allow in future to expand the capabilities of molecular film architecture.

Sustainability, encompassing ecological, economic as well as sociocultural aspects, has become a driving force for many political and administrational decisions. It is no longer enough to follow old practices or rely on profit margins – it is necessary to consider the needs of society and nature in a more holistic way as a larger whole. Sustainability is the key word also in terms of sanitation; ecological sanitation, or ecosan for short, has come to mark the sustainable approach to handling human excreta.In 2014, there are still approximately 2.5 billion people in the world without access to adequate sanitation; 1.1 billion practice open defecation. Lack of sanitation is often – but not necessarily – linked to lack of clean drinking water and poor hygiene. However, poor wastewater treatment also occurs in more developed countries as well as in times of crisis. In the case of natural disasters, even waterborne sanitation, which is often considered the norm, does not prevent the risk of contamination from pathogens. Ecological sanitation aims at a closed cycle of nutrients and absence of water; dry toilets, composting and urine diversion help to return nutrients back into the soil.Based on these challenges, it is necessary to examine alternatives to the current toilet institution that considers waterborne sanitation as the norm. This dissertation explores the feasibility of ecological sanitation as a potential alternative to the mainstream option and the aim is to discover which issues affect the development and change of the current waterborne toilet institution. From a multi- and interdisciplinary point of view, the dissertation determines the various aspects affected by ecosan, such as water and environment, health, culture, education, agriculture, business and technology, and from these points of view develops futures scenarios for sustainable sanitation practices. Technology is here defined beyond artefacts and processes encompassing also knowhow as well as the sociotechnical systems of use, including legislation, culture and practices.The data collected for this research includes expert interviews (n=11), case studies from Ethiopia, Finland, New Zealand and Zambia, and literature review including various policy documents and legislation of the aforementioned case countries to shed light to the current state of ecological sanitation and how it is taken into account from a legal perspective. In addition, a two-round consensus-Delphi survey (n1=44, n2=22) together with theme seminars was conducted among Finnish experts to determine the future potential of ecological sanitation.Through qualitative data analyses, the potential futures and desirable outcomes are mapped with the help of futures research and environmental scanning. The overall challenge of potentially changing the waterborne toilet institution is discussed in the light of the World Polity Theory – with the understanding that global norms are valid everywhere and that change eventually must start from intergovernmental actors rather than political decision makers.This research brings more insight to the relatively unknown and overlooked subject of ecological sanitation. The integrated approach offers new insight into sustainable sanitation practices and closed loop approach from view points of the various sectors of society, including social, economic and ecological aspects. The undisputed challenges of inadequate sanitation facilities faced by 2.5 billion people worldwide are generally not recognized in scientific literature, although several invaluable studies have contributed to the field. Still, concrete results for improvement are still required.The results of this study find that ecological sanitation must be approached from a multidisciplinary point of view in order to understand the variety of sectors impacted by these sustainable practices. As a conclusion it can be stated that the traditional norms in waterborne sanitation are difficult to change but the pressure of limited phosphorus resources and deteriorating or non-existing infrastructure require alternative solutions to the norm. As yet, legislation has generally not allowed or considered the use of human excreta as fertiliser, but practices are slowly changing along with attitudes. Institutions do not change easily but can do so while attitudes, policies and practices all start adopting new ways of operating.It is possible that in the future ecological sanitation will indeed be accepted as a feasible option along with other sanitation methods. This is supported also by the increasing need for sustainable practices in societies. However, in more daunting futures the lack of closed cycles will lead to shortages in resources as well as the lack of wellbeing in communities without access to sanitation. Thus, the research of sustainable sanitation solution is significant and necessary – also in the future. Kestävyys, joka tässä käsittää ekologisen, taloudellisen sekä sosiokulttuurisen näkökulman, ajaa nykymaailmassa useita poliittisia ja hallinnollisia päätöksiä. Enää ei riitä, että seurataan vanhoja käytäntöjä tai luotetaan tulosennustuksiin – on välttämätöntä tarkastella koko yhteiskunnan ja luonnon tarpeita suurempina kokonaisuuksina. Kestävyys on avainsana myös sanitaation osalta; ekologinen sanitaatio tai lyhyemmin ecosan merkitsee kestäviä ihmisjätteen käsittelyn käytäntöjä. Vuonna 2014 maailmassa on ilman sanitaatiota yhä noin 2,5 miljardia, joista 1,1 miljardia tekevät tarpeensa avoimeen maastoon. Sanitaation puute on usein – mutta ei välttämättä – yhteydessä puhtaan juomaveden puutteeseen ja puutteelliseen hygieniaan. Kehnoa jäteveden puhdistusta harjoitetaan kuitenkin myös kehittyneemmissä maissa sekä kriisitilanteissa. Luonnonkatastrofien yhteydessä vesipohjainen viemäriverkosto, jota usein pidetään normina, ei suojaa patogeenien leviämiseltä ja tartunnoilta. Ekologinen sanitaatio tähtää ravinteiden suljettuun kiertoon ja veden säästöön; kuivakäymälät, kompostointi ja virtsan erottelu auttavat palauttamaan ravinteet takaisin maaperään. On välttämätöntä tarkastella vaihtoehtoja nykyiselle käymäläinstituutiolle, jonka mukaan vesivessa on tavoiteltava normi. Tämä tutkimus tutkii ekologisen sanitaation mahdollisuuksia laajemmassa kontekstissa. Tutkimuksessa määritellään ecosanin monipuoliset ulottuvuudet, kuten vesi- ja ympäristövaikutukset, terveys, kulttuuri, koulutus, maanviljely, liiketoiminta ja teknologia. Asiantuntijahaastattelujen ja tapaustutkimusten avulla pureudutaan ekologisen sanitaation nykyiseen tilaan ja siihen, kuinka se näyttäytyy lain edessä. Tapaustutkimukset tehtiin Suomessa, Sambiassa, Etiopiassa ja Uudessa Seelannissa. Teknologian käsite kattaa tässä tutkimuksessa laitteiden ja prosessien lisäksi laajemmin myös tietotaidon ja sosio-ekonomiset järjestelmät, kuten lainsäädännön, kulttuurin ja käytännöt. Aineiston analyysin ohella tehtiin asiantuntijoille kaksivaiheinen Delfoikysely (n1=44, n2=22), minkä avulla hahmotettiin potentiaalisia tulevaisuuskuvia ja haluttuja tuloksia tulevaisuuden tutkimuksen ja toimintaympäristön muutosten tarkastelun kautta. Käymäläinstituution mahdollista muutosta arvioidaan maailmanyhteiskunnan teorian valossa – ymmärtämällä, että globaalit normit pätevät kaikkialla ja muutos lopulta alkaa yleisemmin järjestötoimijoista ja alan ammattilaisista kuin poliittisista päätöksentekijöistä. Laadullisen tutkimusaineiston analyysin avulla kartoitettiin potentiaalisia tulevaisuudenkuvia ja tuloksia tulevaisuudentutkimuksen ja environmental scanning -menetelmän avulla. Nykyisen vesikäymäläinstituution muuttamisen haasteita peilattiin maailmanyhteiskunnan teorian avulla muuhun normistoon – globaalit normit ovat läsnä kaikkialla ja muutos lähtee usein ennemmin kansalaisyhteiskunnan toimijoista kuin poliittisesta päätöksenteosta. Tutkimus tuo lisänäkemystä verrattain tutkimattomaan ja tuntemattomaan aiheeseen. Ekologisen sanitaation tarkastelu monitieteisestä näkökulmasta mahdollistaa suljetun kierron mahdollisuuksien määrittelyn niin sosiaalisesta, taloudellista kuin ekologisesta näkökulmasta. Useista arvokkaista tutkimuksista huolimatta sanitaatio-ongelmat, jotka koskettavat 2,5 miljardia ihmistä, eivät tuletarkastelluksi tieteellisessä kirjallisuudessa kovin usein. Konkreettisia tuloksia asian muuttamiseksi vaaditaan. Tämän tutkimuksen tulokset osoittavat, että ekologista sanitaatiota tulee tarkastella monitieteisestä näkökulmasta, jotta saatavilla olevien kestävien ratkaisujen vaikutukset eri sektoreille ymmärrettäisiin. Johtopäätöksenä voidaan todeta, että perinteiset vesipohjaisen sanitaation normit muuttuvat hitaasti, mutta rajalliset fosforivarat ja infrastruktuurin rapautuminen painostavat etsimään vaihtoehtoisia ratkaisuja ja niiden käyttöönottoa. Toistaiseksi lainsäädäntö ei yleisesti ottaen salli tai edes huomioi ihmisperäisen lannoitteen käyttöä, mutta käytännöt muuttuvat hiljakseen asenteiden, politiikan sekä käytäntöjen muutoksen myötä. On mahdollista, että tulevaisuudessa ekologinen sanitaatio on todella entistä varteenotettavampi vaihtoehto muiden sanitaatioratkaisujen ohella. Synkemmät tulevaisuuskuvat avoimine ravinnekiertoineen johtavat luonnonvarojen loppumiseen ja vähentävät hyvinvointia etenkin yhteisöissä, joissa kunnollisia sanitaatioratkaisuja ei ole käytettävissä. Tämän vuoksi kestävien ja ekologisten sanitaatioratkaisujen tutkiminen on tärkeää ja välttämätöntä – myös tulevaisuudessa.