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Studying the interaction between the dye and the surface as well as how the system reacts to light is important for understanding the electrical and chemical characteristics of dye sensitised solar cells (DSSC). In this thesis, several model systems relevant to dye sensitised solar cells have been investigated for further understanding. But, this thesis starts with the investigation on the popular semiconductor for DSSC application, rutile TiO2(110). At first, the annealing induced migration of defects in single crystals of rutile titanium dioxide have been investigated, and then the next chapter, investigates how defects interact with the molecules of oxygen, water, and air. Firstly, this thesis present an in-situ study of defect migration in rutile TiO2(110) conducted using X-ray Photoelectron Spectroscopy (XPS). The ability of titanium dioixide to split water into OH- and H+ species is heavily dependent on the behaviour of defects in the crystal structure at or near the surface. First, surface and sub-surface defects were created in the crystal by argon ion sputtering. Subsequent in-situ exposure of the defective crystal to liquid water healed the surface defects whilst the sub-surface remained defective. The sample was then annealed whilst XPS was used to monitor the concentration of titanium defects. At low annealing temperatures Ti3+ was observed to migrate from the sub-surface to the surface. Further annealing gradually restored the surface and sub-surface to the defect-free Ti4+ form, during which the changes in abundance of Ti1+, Ti2+ and Ti3+ defects are discussed. In the second experimental chapter, water, oxygen, air, and ambient pressure were applied to defective rutile TiO2(110) surfaces. Before each exposure, defective surfaces were created using Ar+ sputtering to investigate the effect of the corresponding exposed molecules. When exposed to 0.2 mbar water, 1 mbar oxygen, 5 mbar air, ambient pressure at room temperature, 323, 373, 423, 573, and 723 K respectively, the intensity of the oxygen vacancy gradually decreased. Water exposure heals defects by water dissociation whereas during oxygen exposure oxygen dissociates into an oxygen atom and oxygen adatom, where the oxygen atom fills the vacancy and the oxygen adatom dissociates further water and produces two identical OH groups. Further depletion of the defect was observed after exposure to ambient pressure. During annealing in ambient pressure, a rapid depletion of Ti intermediate oxidation state was observed as temperature increased. This is more likely due to the bulk assistance (through titanium interstitial and oxygen vacancy diffusion mechanisms) oxidation mechanism's progressive conversion of Ti1+ defects to Ti4+ via intermediate oxidation states . In the next experimental chapter, bi-isonicotionic acid has been deposited onto rutile, anatase and mesoporous TiO2. X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) have been used to obtain chemical information and map out the density of states for the system. We find that the LUMO lies entirely within the band gap of the rutile, anatase and mesoporous titania, as a consequence, the electron transfer between LUMO and substrates is electronically forbidden. But the LUMO+1 and LUMO+2 states of the core excited molecules are overlapped with the unoccupied states in the substrate. So, it is possible to transfer charge from molecules to substrate. The core-hole clock is implemented using resonant photoelectron spectroscopy (RPES) data. The charge transfer time of bi-isonicotinic acid on rutile and anatase titania is found to be comparable. While the obtained charge transfer time for bi-isonicotinic acid on mesoporous titania is longer than the rutile and anatase. Finally, the chemisorbed and physisorbed coverage of N3 dye complex on mesoporous TiO2 has been investigated. X-ray photoemission spectroscopy (XPS) spectra reveal the presence of protonated carboxylic groups, which might be evident of the absorption of N3 on mesoporous substrate bonded through a mixture of bidentate and monodentate bonding geometries. From the density of states for the system we found that the LUMO lies entirely within the band gap of the mesoporous titania, and the electron transfer between LUMO and substrate is electronically forbidden. The intense features and vibronic coupling observed in RIXS and RPES have been discussed thoroughly. The RIXS, RPES and calculated density functional theory (DFT) have been combined to provide an understanding of the electronic structure of complex molecules. The orbital contributions of the bi-isonicotinic acid and thiocyanate ligands were used to interpret the obtained RIXS and RPES data.

The main aim of the study is to explore and understand the potential for CSR practices to generate and confer unique benefits to a firm from their involvement in its activities, and exploring the scope to connect CSR and its accompanying benefits with the entrepreneurial practices of the firm. Following social constructionist philosophy this study was conducted to understand the construction of reality at the interface of CSR and entrepreneurship in large exemplary CSR practicing and entrepreneurial firms. Focusing on strategic CSR (SCSR) theories and opportunity based view of entrepreneurship, this study followed corporate entrepreneurship (CE) and social entrepreneurship (SE) theoretical underpinnings to establish a link between CSR and firm entrepreneurship to develop a theoretical framework for corporate social entrepreneurship (CSE) for creating economic, social and shared value. This is a qualitative exploratory study and the research site was Bangladesh. Case study method was used as the main method in this study and semi structured interviews as the main method for data for case studies. Secondary sources of information, company records, project profiles and other archival data were also used in this study. Four purposively selected case firms which are exemplary CSR and entrepreneurial firms operating in Bangladesh are selected for case study along with other external stakeholders. Two phases of fieldwork were carried out as per the research plan to collect rich and deep data. Data analysis considered 32 usable interviews of first phase of fieldwork and 9 follow-up interviews of second phase of fieldwork. During the first phase of fieldwork after initial purposive sampling, snowballing also followed to capture deep and thick data to generate rich insights. Since this study mainly followed qualitative cross case analysis, four purposively selected case firms comprised main data set which are exemplary CSR and entrepreneurial firms operating in Bangladesh. Cross case analyses were done to draw out the findings. Transcribed interview data were analyzed using Atlas.ti qualitative data analysis software. Open coding was used to analyze data following thematic coding process. Code co-occurrence analyses were used to do cross case analysis. Within the fields of CSR and entrepreneurship, this study explored the interaction between CSR and firm entrepreneurship focusing on corporate entrepreneurship and social entrepreneurship domains. Findings of the study suggest that the interaction of CSR practices with firm entrepreneurship may bring a better climate for exploring and exploiting business opportunities through promoting entrepreneurial behaviour, scope for innovation and better strategic and entrepreneurial practices for creating shared value. Moreover, this interaction along with social oriented vision, strategic management practices, internal environment and value based culture together are conducive for enacting corporate social entrepreneurship (CSE) to promote robust CSR practices and greater value creation. Due to qualitative cross case analysis involving limited number of cases and primarily dependency on the interview data, generalizability of the findings are limited to theoretical inference. Based on the empirical work, developed CSE theoretical model is the outcome of data analysis in a triangulating fashion which offers validity and reliability. The main implications of this study is that addressing social problems through exploring and exploiting opportunities in the shared value creation space, managers may create an enabling environment and pursue strategies which are conducive for socio-entrepreneurial business practices. Also, CSE theoretical framework is expected to be strategic and entrepreneurial simultaneously which can be effective in bringing competitive advantage for firms.

Accurate prediction of long-term moisture expansion in fired clay ceramics requires finding a relationship between the reactivity of a ceramic material with moisture and time. Recently a (time)1/4 law has been proposed which provides a precise relationship between moisture expansion and mass gain in fired clay ceramics and time. However, mass gain studies rather than expansive strain studies provide a more accurate and fundamental measure of the reactivity of fired clay ceramics with moisture. The possibility of using the (time)1/4 law to describe rate of mass gain and consequently to predict moisture expansion in fired clay ceramics with time requires study of the effect of chemical composition and firing temperature on the linear dependence of mass gain on (time)1/4. Pure kaolinite as well as kaolinite mixed with controlled additions of alkali and alkaline-earth metals were employed in this study. These materials were fired at temperatures between 800°C and 1200°C. Mass gain due to the chemical combination of the fired materials with moisture was measured using a recording microbalance under tightly controlled environmental conditions of temperature and relative humidity. The mass gain results show that the (time)1/4 law can be used to obtain an accurate linear relationship between long-term mass gain and time at almost all firing temperatures and at all different compositions. The presence of alkali metals was found to strongly affect the chemical combination of fired clay ceramics with moisture and hence affect the rate of mass gain. On the other hand, alkaline earth metals were found to produce similar reaction kinetics to kaolinite alone. BET surface area and X-ray diffraction results confirm that there is a correlation between the reactivity with moisture and both the specific surface area and crystallinity of fired clay ceramics.

With an increasing number of hand-held electronics, gadgets, and other smart devices, data is present in a large number of platforms, thereby increasing the risk of security, privacy, and safety breach than ever before. Due to the extreme lightweight nature of these devices, commonly referred to as IoT or `Internet of Things', providing any kind of security is prohibitive due to high overhead associated with any traditional and mathematically robust cryptographic techniques. Therefore, researchers have searched for alternative intuitive solutions for such devices. Hardware security, unlike traditional cryptography, can provide unique device-specific security solutions with little overhead, address vulnerability in hardware and, therefore, are attractive in this domain. As Moore's law is almost at its end, different emerging devices are being explored more by researchers as they present opportunities to build better application-specific devices along with their challenges compared to CMOS technology. In this work, we have proposed emerging nanotechnology-based hardware security as a security solution for resource constrained IoT domain. Specifically, we have built two hardware security primitives i.e. physical unclonable function (PUF) and true random number generator (TRNG) and used these components as part of a security protocol proposed in this work as well. Both PUF and TRNG are built from metal-oxide memristors, an emerging nanoscale device and are generally lightweight compared to their CMOS counterparts in terms of area, power, and delay. Design challenges associated with designing these hardware security primitives and with memristive devices are properly addressed. Finally, a complete security protocol is proposed where all of these different pieces come together to provide a practical, robust, and device-specific security for resource-limited IoT systems.

Spinal cord injury (SCI) is one of the most common sources of motor disabilities in humans that often deeply impact the quality of life in individuals with severe and chronic SCI. In this dissertation, we have developed advanced engineering tools to address three distinct problems that researchers, clinicians and patients are facing in SCI research. Particularly, we have proposed a fully automated stochastic framework to quantify the effects of SCI on muscle size and adipose tissue distribution in skeletal muscles by volumetric segmentation of 3-D MRI scans in individuals with chronic SCI as well as non-disabled individuals. We also developed a novel framework for robust and automatic activation detection, feature extraction and visualization of the spinal cord epidural stimulation (scES) effects across a high number of scES parameters to build individualized-maps of muscle recruitment patterns of scES. Finally, in the last part of this dissertation, we introduced an EMG time-frequency analysis framework that implements EMG spectral analysis and machine learning tools to characterize EMG patterns resulting in independent or assisted standing enabled by scES, and identify the stimulation parameters that promote muscle activation patterns more effective for standing. The neurotechnological advancements proposed in this dissertation have greatly benefited SCI research by accelerating the efforts to quantify the effects of SCI on muscle size and functionality, expanding the knowledge regarding the neurophysiological mechanisms involved in re-enabling motor function with epidural stimulation and the selection of stimulation parameters and helping the patients with complete paralysis to achieve faster motor recovery.

Pavement layer materials are typically assumed to be isotropic in determining pavement responses, such as stress and strain. The main benefit of the isotropic assumption is that stiffness defined by modulus of elasticity (E-value) is equal in all directions. In reality, stiffness along vertical and horizontal (i.e., and ) may vary due to density gradients in compacted layer materials caused by vertical compaction during construction. Therefore, pavement layer materials with different vertical and horizontal modulus (i.e., \u2260 ) are cross-anisotropic. Past studies have reported that degree of cross-anisotropy, ( ) ranges from 0.2 to 0.85 in Asphalt Concrete (AC) layers. Yet, the presence of cross-anisotropy is not considered in pavement layers for determining stress and strains, which are used for prediction of pavement distresses such as rutting and fatigue cracking. Ignoring the presence of AC cross-anisotropy may lead to an error in stress-strain calculations, and in pavement distress value predictions. To this end, this study examines the effects of cross-anisotropy on pavement stress-strain and thereby, evaluates the importance of cross-anisotropy in pavement design. In addition to cross-anisotropy, AC modulus is temperature and frequency dependent. Pavement temperature varies not only at different times over a day but also at different seasons over a year. Also, temperature is not constant over the depth of an AC layer which leads to a non-homogenous distribution of AC stiffness. AC modulus varies due to different loading frequencies caused by variable speed of moving vehicles. Unbound layers such as base and subbase are stress-dependent. The stiffness of an unbound layer differs at different months over a year due to varying moisture contents. This study considers all of these factors such as temperature, frequency, and moisture with material cross-anisotropy through laboratory testing and finite element modeling. In this study, a dynamic Finite Element Model (FEM) is developed based on the geometry of an instrumented pavement section at Milepost (MP) 141 on I-40, Rio Puerco, New Mexico and deflections, stress, and strains are predicted under truck tire pressure. Two different material models are employed: (i) generalized cross-anisotropic and temperature dependent viscoelastic model, and (ii) nonlinear elastic and stress-dependent model. The first one is for the AC layer whereas the second one is for unbound layers such as base and subbase courses. In this study, dynamic modulus tests were conducted in the laboratory on field-compacted vertical and horizontal AC cores to determine the parameters required for developing the generalized cross-anisotropic viscoelastic model. Resilient modulus tests were conducted on granular aggregates collected from the base and subbase layers to develop nonlinear elastic and stress-dependent material model. After integrating these material models, the dynamic FEM is simulated under a Falling Weight Deflectometer (FWD) test type load (79.6 psi over a circular area with 6 inch radius) for model validation. The simulated responses are compared to in-situ deflections, stress, and strains under a FWD test. It is observed that the simulated pavement responses are close to in-situ responses. Using the validated model under non-uniform vertical tire-pavement contact stress, FEM simulations are run at varying n-values and temperatures to determine tensile strain at the bottom of AC layer and vertical compressive strains in all layers. It is observed that strains are sensitive to material cross-anisotropy and strains with cross-anisotropy assumption are greater than those with isotropy assumption. In particular, both horizontal tensile and vertical compressive strains increased in case of AC cross-anisotropy, whereas only vertical strains increase in case of unbound layer cross-anisotropy. These strain variations due to cross-anisotropy increase at high temperature and in presence of stress-dependent unbound layer. In order to determine pavement distresses, simulated strains are used to determine damage due to fatigue and permanent deformation using Miners rule. In case of AC cross-anisotropy, damage decreases as n-value increases towards isotropy ( ). However, unbound layer cross-anisotropy leads to an increase in fatigue damage as n-value increases towards isotropy. It is also observed that damage due to AC cross-anisotropy is very high compared to unbound layer cross-anisotropy. It indicates that earlier pavement damage is mostly caused by the AC cross-anisotropy. That is, AC cross-anisotropy is more important than the unbound layer cross-anisotropy when considering rutting and fatigue damage only. This study recommends to incorporate the AC cross-anisotropy, at a minimum, in pavement analysis and design.'

We demonstrate a simple and inexpensive sensor capable of weighing microgram- scale objects in fluid. When objects flow through a glass tube that is vibrating at its resonance frequency, the frequency changes by an amount that is inversely proportional to the object’s buoyant mass. By measuring this frequency change, microgram objects can be weighed in fluid with nanogram-scale resolution. These sensors are easily fabricated, require no labels or tags, and are versatile, making them a valuable instrument for both in situ and laboratory measurements. They are fully automated and can measure any appropriately sized object in a wide range of biological, physical, and chemical applications. Using resonating glass tubes, we demonstrate the mass change detected in zebrafish (D. rerio) embryos as they are exposed to various toxicants, the water uptake and germination of dry seeds as they are put in water, and degradation rates in biomaterials in different fluid media.Aside from the experimental data from two separate resonator geometries, we also present simulations on other geometries that can be explored for these sensors. We explore the advantages and disadvantages in each geometry and potential sources of measurement error associated with the resonators. The simulations allow us to predict the resolution and the quality factor of the resonator before a prototype is developed.We took advantage of various rapid prototyping techniques, including 3D printing for developing these sensors. In this process, we discovered that 3D printed parts produce a toxic effect in zebrafish embryos. This observation led to a separate project, in which we assessed the toxicity of printed parts from two main classes of commercial 3D printers, fused deposition modeling and stereolithography. We used zebrafish embryos, a widely used model organism in aquatic toxicology and monitored them for rates of survival, hatching, and developmental abnormalities. We found that parts from both types of printers were measurably toxic, with STL-printed parts significantly more toxic than FDM-printed parts. We also developed a simple post-printing treatment (exposure to ultraviolet light) that largely mitigates the toxicity of the STL-printed parts. Our results call attention to the need for strategies for the safe use and disposal of 3D-printed parts and printer waste materials.

Falling Weight Deflectometer (FWD) test data are processed by backcalculation software to obtain modulus of layer materials of airport pavements. Currently, several backcalculation software are available. However it is not known which software produces accurate and consistence modulus values. In this study three backcalculation software; namely, BAKFAA, EVERCALC, and MODULUS are evaluated for consistency and accuracy. To examine accuracy, software predicted modulus values are compared to the laboratory tested modulus values of soils, aggregate, and asphalts. Consistency is examined by statistical analysis using three sets of FWD deflection data produced by three loads with magnitudes of 9, 12, and 16 kip at an identical location of an airport pavement. It is shown that EVERCALC software produces more consistent and accurate modulus values than the BAKFAA and MODULUS software. A concern with the available backcalculation software is that their analysis algorithms are based on layered elastic theory with linear materials models. In addition, they consider static loading, which is not the true representation of the dynamic loads applied in a FWD test in the field. To this end, this study performs a dynamic analysis of the FWD deflection basin using a finite element method (FEM) with the consideration of non-linear materials models. Results show that FEM predicted deflections have similar trends of the field measured deflections. However, a number of trial combinations of inputs and FEM models may be required to produce an identical match between the predicted and measured deflections. It is recommended that this approach be the subject of future studies.

The quest for identity is becoming one of the most politically charged issues at the start of the third millennium. The transformative processes that are occurring as a result of globalization, as well as the mass population migrations that took place in the twentieth century, explain why the question of identity has become so central a political driving force to both the well-established democracies of the West and the post-colonial societies as they evolve in their quest toward modernization. In reaction to the dehumanization and alienation brought about by the post-industrial economies, new dissident and “deviant” identities are being forged. The concept of French citizenship, a universal abstraction as conceived by the Enlightenment, is being challenged by specific forces relating to gender, culture, sexual orientation but especially those tied to ethnicity and religion, once considered as belonging to the past. New identities are being forged around sub-cultures associated with consumer habits and leisure time activities such as soccer and Rai music. Others seek refuge and legitimacy searching for roots in mythical pasts and imaginary ancestry, or in transnational movements and causes. Facing simultaneously the pressures of assimilation and exclusion within the society, ethnicity and religion become alternative choices to new immigrants who also become victims of the socio-economic vagaries of globalization. The struggle for the recognition of a dissident identity is a fight for power. Representative democracies gradually absorb dissident currents into their mainstream, Islam, however, represents a particular challenge as it has become an ideological opponent to the Western rationalism. The sheer number of followers and the size of its territory appear menacing to the West, making the migrants of Muslim descent doubly undesirable, both as poor neighbors and as suspected radicals. The uprisings of the marginalized suburbs are a symptom of this crisis. The 2001 attacks on the World Trade Center only amplified these fears. This study seeks to analyze the efforts undertaken by the French government since the 1990s, to ease the social integration of its divers minorities without sacrificing the norms and principles that make the singularity of the French national identity.