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The article is devoted to confirmation of a mechanism of aeration classification in drum-shelf friction separators of materials, the components of which are distinguished by a wide range of “sailage” in order to increase the separators efficiency and the quality of finished products in technology of components separation of ore and non-ore materials. Using aerodynamics of bodies of arbitrary shape in a directed air flow, a mathematical model is obtained of aeration classification of particles of material components, depending on their physical properties, unified by an integral criterion of “sailage”, and controlled airflow parameters with separate accounting of influence of particles velocity and flow. Equations are obtained for calculation of geometric parameters of a unit of aeration classification friction drum – shelf separator depending on integral criterion of “sailage” determined by shape, size, density of initial raw material and air viscosity providing for maximum quality of stratification of the feedstock and, as a result, increasing the production efficiency and the quality of the separated material. The efficiency of aeration classification with the use of a controlled air flow is confirmed, as well as sufficient convergence of experimental and calculated data. The additive mathematical model has confirmed the high efficiency of application of aeration classification in drum-type friction separators to improve the quality of stratification with reference to initial raw materials, components of which differ in a wide range of “sailage”.

The decay resistance of European (Populus tremula L.) and hybrid (P. tremula x tremuloides) aspen wood against brown-rot fungi was investigated after three different treatments, i.e. conventional drying, press drying and heat treatment. For both aspen species, the mass loss after exposure to Gloeophyllum trabeum was higher than after exposure to Coniophora puteana, regardless of the wood treatment. Conventionally and press dried aspen wood had similar mass losses. However, heat treatment appears to be an effective method to improve the decay resistance of aspen wood, reducing the mass loss by about 30% compared with conventional and press drying. As a function of mass loss, wood exposed to G. trabeum had lower moisture content than wood exposed to C. puteana. This is thought to be due to differences in the degradation pattern between the two brown-rot fungi. On the other hand, European aspen appears to be slightly more resistant to decay than hybrid aspen.

International audience; Surface coating and bulk treatment of wood are two effective measures which can, individually or conjointly, protect exterior wood from deterioration. This paper reports on the blue stain attack in coated wood, untreated and modified with DMDHEU, after six years of natural exposure.

Residues of Bagasse (Saccharum officinarum L.), canola (Brassica napus L.) and hemp (Cannabissativa L.) as well as industrial wood chips in various proportions from 0–100% were used as raw materials for the main component of the middle layer in urea formaldehyde bonded particle boards. peerReviewed

Chemo-thermo-mechanical pulps (CTMP) were made from waste particle- and fibreboards. Medium density fibreboards (MDF) were made from industrial refiner fibres in combination with the CTMP using urea-formaldehyde resin as a binder. The physical properties and the formaldehyde content of the MDF were determined. The results reveal that MDF made from CTMP of waste particle- and fibreboards meet the standards according to EN 622-5, type MDF. The bending strength and internal bond of MDF made from industrial TMP is higher compared with MDF from chemo-thermo-mechanical pulps from waste panels. However, the thickness swelling of MDF made from pulps derived from waste panels is clearly lower compared with that of MDF made from industrial TMP. Furthermore, MDF made from pulps derived from waste panels show a lower formaldehyde content than MDF from virgin fibres. It seems that residues of chemicals from the pulping process (CTMP) acts as a formaldehyde scavanger.

In this paper a hydrogen-based air-conditioning unit, which can also function as range extender for electric vehicles, is studied. This hydrogen A/C-unit utilizes the endothermic reaction of hydrogen desorption from metal hydrides to generate a cooling effect. Within DLR’s Next Generation Car project a prototype system was developed and characterized on a test bench. This system represents a world’s first proof of concept, where two metal hydride reactors are coupled to a fuel cell to establish a process which provides cooling power without any electrical power input. The measured cooling power is directly coupled to the hydrogen mass flow taken from the reactors, thus being indirectly linked to the fuel cells electrical power output. A maximal heat flow of 0.72 kW was detected at 5 kW electric fuel cell power. The paper concludes with the discussion of an appropriate vehicle integration concept for this innovative technology.

For sensible thermal energy storage in Concentrating Solar Power (CSP) plants, a molten salt mixture of 60 wt% sodium nitrate (NaNO3) and 40 wt% potassium nitrate (KNO3), known as Solar Salt, is commonly utilized. The paper presents semi-empirical estimation results of the density of Solar Salt and alternative molten salt mixtures with low melting temperatures in a range from 70 °C to 140 °C. These mixtures are Hitec, HitecXL, LiNO3–KNO3–NaNO3 and a multicomponent mixture. The paper shows that density values of mixtures can be closely predicted from single salt densities. The paper examines different estimation rules for mixtures. The quasilinear volumetric additivity rule (QVAR) is known for ternary reciprocal systems. For the first time, the presented work extends the QVAR to multicomponent mixtures. Temperature-dependent densities of selected salt mixtures of the system Ca,Li,K,Na//NO2,NO3 were estimated. Estimations are motivated by a fast and reliable method compared to time-consuming and error-prone measurements of several mixtures.

The paper focuses on the performance and aging behavior of lithium nickel cobalt manganese oxide commercial standard material (NCM-111) which is improved with a post synthesis process in order to enhance the cathode active material of lithium-ion pouch cells regarding their capacity and cyclic stability. The aging behavior of the cells is analyzed with electrochemical impedance spectroscopy (EIS) during long-term electrochemical load cycling tests based on the Common Artemis Driving Cycle (CADC). Additionally, post-mortem investigations using scanning electron microscopy (SEM) and X-ray diffraction (XRD) were performed. The results demonstrate that post-processing of electrode active material is an effective tool to improve the properties of lithium-ion electrode materials, especially regarding high energy applications and lifetime optimization. The paper bridges the gap between lithium-ion battery electrode material development and the necessary cell testing under automotive relevant conditions which is important for the evaluation of new lithium-ion battery materials for automotive applications.

In this paper, we study the methods for calculating beams with skating in the lower belt of both the Ibeam and box sections. Based on the dependences presented in the existing methods, the stress-strain state of single-beam bridge cranes was calculated at the points of contact of the wheels of the hoist and beam belt, with a box section with rolling along the bottom. Box-section crane cranes have greater rigidity and stability compared to the I-beam section, in addition they allow you to increase the span without sacrificing the crane's lifting capacity. SolidWorks Simulation also performed a finite element analysis of the stress-strain state of boxsection beams with skating along the lower belt. The main advantage of the finite element method is the ability to split into finite elements areas of any shape and, thus, the ability to calculate the stress and strain fields in real details, taking into account all their design features, which ensures high accuracy of the calculation. On the basis of the results obtained, the dependences of stresses on the thickness of the lower girder beam, the position of the hoist wheels were studied, an approximating function was constructed, and a simpler engineering calculation method was proposed that allows one to reduce the number of calculations

Current measurement techniques do not allow the visualization of the return air flow of open volumetric receivers in solar tower power plants. The reason is that the region of interest is irradiated by concentrated solar radiation and is located on top of a tower. Therefore, a novel method of measurement, the Induced Infrared Thermography (IIT) is introduced within this paper. With this method the return air can easily be observed with an infrared camera. As air has a very low emissivity in the infrared region the activity has to be induced by the addition of an infrared-active component, here carbon dioxide. The temperature of the infrared-active component has the greatest influence on the signal strength but the mole fraction of the component and the distance to the infrared camera are also important. Due to temperature restrictions, the measured signal to noise ratio is low and therefore several post-processing steps have to be conducted to visualize the return air. The most important step for the visualization is subtracting a background image. Furthermore, a video filter is employed in order to remove noise. A time series of ITT images can be used to obtain information on the velocity fields of the flow. The process, called Infrared Image Velocimetry (IRIV) here, is similar to Particle Image Velocimetry (PIV) and is applied in this paper to external fluid flows of the open volumetric receiver. As IRIV is in an early stage of development the depicted results are treated as qualitative vector fields.

Understanding the phonologic structure of the Turkish language, is not possible to examine not only the written language. Investigation and examination of the local dialects of Turkish language will shed light on many points that can not be understood. Dialect studyings are directly resource of Turkish Language. It also contributes other disciplines such as ethnology, etymology, sociology, history, folklore and etc. This paper includes subsequents of compilation which is compiled from Asarcık (district of Samsun), phonologic structure of Asarcık dialect and it’s countryside dialects by us. It is used narrow-area method while compiling. Our compilation study contains detailed compiling dialects’ all towns and villages of Asarcık (district of Samsun). It is examined phonologic and morphologic data of Asarcık’s dialects; and also is compared this data with the other Anatolian dialects. It is not possible to understand the structure of the Turkish language, its’function and characteristics by only investigating it through recognised official written and standardised language. Therefore studying and searching the local language of the Turkish language brings light to questions not understandable. Additionally dialect studies not only being source of a direct reference for the Turkish language but also has an indirect input for the sciences such as ethnology, etymology, sociology, history and folklore. Asarcık is a centre where the ethnologic mixture is intensely populated. In order to study the Turkish tribes who settled here need to identify the region’s dialect efficently. As a result of the data that will be gathered through the Asarcık dialect analysis, will enable to question the correctness of the information of the history. With this announcement we will be showing the results of our study on Asarcık dialect During the study in Asarcık central and reached the whole villages where the data gathered. Method of narrow field selected, the entries have been considered in as much detail as possible. Particular attention will be given to Asarcık dialect’s phonologic and morphologic results. Also these phonological results will be compared with the surrounding dialects and the Turkish of Turkiye; in phonologic and morphologic context other dialects and Asarcık dialect’s smilarity and differences variations will be demonstrated.

The relevance of this paper consists in the further development of a new direction in mineralogical crystallography — dynamic crystallomorphology, which allows one to obtain information on physical and chemical conditions of formation of mineral deposits by changing the form of crystals during their growth. Purpose of the work: theoretical substantiation and development of the method of morphokinetic analysis and methods for constructing morphogenetic diagrams of natural crystals. Research methodology: the study of mechanisms and causes of the change in the shape of crystals based on the observed mineralogical facts and idealized geometric models, as well as morphometric analysis of combination shapes of crystals. Results. Four kinematic mechanisms for preserving and changing the shape of crystals are considered. It is proved that the crystal shape of a certain min eral is directly determined by the supersaturation of the solution (undercooling a melt, the pressure of supersaturated vapor). All other factors, such as temperature, pressure, pH, redox potential Eh, activity of other ions involved in the mineral-forming process, affect the shape of crystals indirectly changing the solution supersaturation. It was shown that, depending on the direction and rate of change of supersaturation, 7 morphogenetic rows of closed or quasi-closed simple crystallographic forms (SCF) can be distinguished in each class of symmetry. Each row represents a SCF sequence in which each successive SCF replaces the previous one. Morphogenetic series were distinguished: 1) regressive evolutionary; 2) progressive evolutionary; 3) regressive intermittent; 4) progressive intermissive; 5) regressive shocking; 6) progressive shocking; 7) variable. A method is proposed for constructing morphogenetic diagrams using a diagram for a regressive evolutionary SCF series as an example (m3m symmetry of a cubic syngony). The morphogenetic diagram is given of the variable series based on the example of a particular cassiterite crystal.

The relevance of the work is conditioned by the need for a more complete study of the mineralogy of rare-metal granite pegmatites of the Lipovskoye vein field. The purpose of the study is to describe the findings of native metals (gold, silver, copper, lead, bismuth and tungsten) in granite pegmatites of the Lipovskoye vein field. Research methodology. Detailed study of chemical composition, morphology and relationships of native metals with associated minerals. For this study we have chosen samples from the three types of granitic pegmatites – classical quartz-feldspar (mostly intragranitic), desilicated (apogranite plagioclasite) and contaminated lithium-bearing. Results. The paper describes native metals (gold, silver, copper, lead, bismuth and tungsten), which we have found in rare-metal pegmatites of the Lipovskoye vein field. The discovery of the native metals is the first on this facility. The microprobe analysis of such native metals as gold and silver showed the variability of their chemical composition from the type of pegmatite in which they are present. The formation of native lead should be logically linked to the destruction and recrystallization of high uranium thin rims of zircons. The formation of bismuth and tungsten may have occurred during recrystallization of accessory tantalumniobates. Summary. The finding of the native metals in granitic pegmatites is quite explainable. This is because these core rocks are formed in the post-magmatic stage of the silicate crystallization intrusions and they can contain typomorphic rocks for these metals. The absence of mineral concentrators (sulfides) in pegmatites clearly explains the small size and high dispersion of metals.

The mathematical model is elaborated and analysis of the system is done on the adaptive voltage control and reactive power compensation of AC traction to minimize active losses. Sharp changes in the load shoulder traction substation, which includes a compensating installation, leads to a decrease in the voltage loss in the system to it, and therefore to an increase in its power, which in turn will cause an additional increase in voltage in the traction network. To this voltage does not exceed the permissible, it is necessary to use longitudinal-transverse compensators with adjustable parameters. The purpose of this article is to justify the selection of an algorithm for adaptive voltage regulation and parameters of the reactive power compensator based on continuous measurement of the external power supply system in the simulation of its operation modes, taking into account the influence of the traction power supply system. In particular, it provides for the possibility of regulating the voltage of the traction transformer under load when included in the traction network of longitudinal-transverse compensators installations, taking into account the longitudinal and transverse asymmetry of the power supply system parameters and its real parameters, as well as the non-linear nature of the current-voltage characteristics of the electric rolling stock. In this paper, we will consider in a first approximation a power supply system with a single traction substation with an adjustable transformer equipped with voltage regulation under load, and an adjustable installation of transverse capacitive compensation of compensating installation.

The paper considers the research of steel structures of a combined knife system of a scraper. The necessity of reinforcing the metal structures of the scoop cutting organ of the combined knife system and the introduction of a high-speed device into its construction for fixing it to the foot plate during the development of the soil are established.

For aerodynamic profile tests on aircraft models, boundary-layer transition detection is of great interest. Under ambient flow conditions the infrared technique (IR) is a well-established image-based method for this purpose. In high Reynolds number tests that are conducted at cryogenic temperatures the IR technique is of only limited suitability. In contrast, the image-based Temperature-Sensitive Paint (TSP) technique is well suited for these conditions. Boundary layer transition detection by means of TSP generally requires an artificial temperature difference between model surface and flow. For wind tunnels operated under cryogenic conditions changing the liquid nitrogen injection rate of the working fluid causing a rapid change of the flow temperature can generate this temperature difference (“temperature-step method”). The drawback of this temperature-step method is that during the change of the flow temperature neither the Reynolds nor the Mach number can be kept constant. To overcome this problem, we have recently published an alternative approach where Carbon Nanotubes (CNT) are used to electrically heat the model surface and thus generate a well-defined temperature difference to visualize laminar-turbulent transition. The combination of CNT and TSP, which we call cntTSP, delivered excellent results in different wind tunnel tests from ambient temperatures down to 100 K. The cntTSP sensor visualizes the surface boundary-layer conditions as temperature distribution based on different heat transfer coefficients in the laminar and turbulent flow. Compared to the temperature-step method the cntTSP approach has the advantage and potential to measure boundary-layer transition in a time-resolved manner, e.g. on wind tunnel models when the wind tunnel is operated in continuous pitch traverse mode, which is desired in order to improve the data productivity of the wind tunnel tests. In this paper, the applicability of cntTSP to a continuous moving model (pitch-traverse or pitch-sweep test) is investigated in the pilot facility of the European Transonic Windtunnel (PETW). The laminar to turbulent boundary-layer transition appearing on a 2D model is visualized and compared between the pitch-traverse and pitch-pause tests.

This study initiates the gradual upgrade of the DLR reaction database The upgrade plan has two main steps: an optimisation of the C1–C4 oxidation chemistry and a revision of the polyaromatic hydrocarbon (PAH) formation sub-mechanism based thereupon. The present paper reports the main principles applied to model improvements and results obtained for the acetylene (C2H2) oxidation sub-mechanisms. The principle acetylene oxidation reactions have been revised as well as the detailed chemistry of important intermediates, i.e. methylene, ethynyl, vinylperoxy radical and also diacetylene, vinylacetylene and higher diacetylenes, important for PAH formation. The uncertainty intervals of the studied reactions were statistically evaluated, providing general bounds for the performed modifications to reaction rate coefficients. The first stage of the presented update was performed through revision of the thermochemical data and model optimisation on ignition delay data and laminar flame speed data, since they exhibit lower uncertainty in comparison to species profile data. The final model optimisation was obtained through simulations of concentration profiles measured in shock tubes and laminar flames for improvement of the reaction paths and rate coefficients related to acetylene pyrolysis and PAH precursor formation. Approximately 500 data points were analysed. The updated reaction mechanism predicts all simulated experimental data, also not included in the optimisation loop data prom plug flow and jet-stirred reactors, either with good or satisfactory agreement. It was found that the vinylperoxy radical formation and consumption dictate the reaction progress at low temperatures. The performed study clearly determined that acetylene combustion proceeds through the strongly coupled reaction paths of fuel oxidation and PAH precursor formation; the same species are involved in these parallel processes. Therefore, the self-consistent reaction model for acetylene combustion could be obtained only by an optimisation performed on the experimental dataset encompassing both processes.

Mixture fraction measurements in a jet-in-cross flow configuration at high pressures (15 bar) and temperatures (above 1000 K) were performed using planar laser induced fluorescence of nitric oxide (NO-PLIF) as trace species. The goal was the evaluation of this tracer LIF technique for the characterization of the mixing of fuel and hot exhaust gas in the mixing channel. The fuel (natural gas (NG) or H2/N2/NG mixture) along with the tracer were injected into the crossflow of the exhaust gas and PLIF measurements were performed in different planes. In order to relate the measured NO-LIF signal to fuel concentration and mixture fraction, effects of pressure, temperature and species concentration were taken into account. Numerical calculations and spectroscopic simulations that mimic the experimental conditions were performed to identify excitation schemes that give optimum correlations between the NO-LIF signal and the mixture fraction. The measured NO-PLIF images were transformed into mixture fraction plots using the computed correlations. The paper reports on the experimental challenges encountered during the measurements and the steps taken to overcome those difficulties. Examples of mixture fraction distributions are presented and discussed. The paper concludes with a detailed analysis on the accuracy of the measured mixture fraction values.

Summary This paper focuses on corrosion characteristics of cast and forged aluminium 6061 based composites reinforced with TiB 2 particles. Composites were synthesised by in situ technique using potassium hexafluorotitanate salt (K 2 TiF 6 ) and potassium tetrafluroborate (KBF 4 ) halide salts by stir casting route at a temperature of 850 °C. Cast aluminium alloy and its in situ composites were subjected to open die drop forging at a temperature of 500 °C. Both cast and forged alloy 6061 and in situ composites were then subjected to microstructure studies, salt spray test. Salt spray test was conducted as per ASTM B117 standard test procedure using 5% sodium chloride test solution. Result reveals that, forged alloy and its in situ composites exhibited improved corrosion resistance compared to cast ones.

Thermal energy storage is an essential advantage of solar thermal power plants. The present paper focuses on latent heat storage using a phase change material (PCM). The paper lists literature and gives the current status of PCM work in the temperature range 200 to 350 °C. The system KNO3-NaNO3 is discussed in detail in terms of their thermo-physical properties in the liquid and solid phase. A comparison of literature data and own measurements for the density, heat capacity, thermal diffusivity and thermal conductivity is presented. Measurement results with the following methods are discussed: helium pycnometer, differential scanning calorimeter (DSC) and laser flash. Missing data of the thermal diffusivity and thermal conductivity are partly supplemented. Consistent thermo-physical properties in the liquid phase are presented.

International audience; For the production of spliced veneers the veneers are coated with thin cellulose fleece or special paper layers, and thereby thin composites are generated. This article describes the mechanical properties of such a composite material consisting of 0.35 mm beech ( L.) veneer and a 0.12 mm cellulose fleece bonded with a PVAc adhesive.

This paper reports heat flux measurements on parabolic trough receivers, which are integrated to calculate the receiver overall heat loss. Integrated heat fluxes yield an overall heat loss value which agrees with DLR ThermoRec heat loss measurements within ± 5 %, in the simplified case of assuming a homogeneous heat flux distribution around the receiver circumference. Heat flux measurements also allow separating glass envelope and shielded bellow heat loss terms for receiver thermal modelling. Shielded bellows only represent 3 to 4 % of the receiver total length at ambient temperature, however heat flux measurements show that their contribution to the overall receiver heat loss ranges from 5 to 15 %, depending on the shield construction and the absorber temperature. The receiver specific heat loss thus tends to lie above the glass envelope specific heat loss. Almost homogeneous heat flux values are measured along the glass envelope length (variation below 5 %), while more inhomogeneous heat flux values are observed over circumference of the glass envelope (variation between top and side of 17 %). The measurement setup analysis shows a good repeatability, although a proper mounting of heat flux sensors is important in order to avoid systematic biases.

A high share of heating energy consumption by buildings is due to poorly insulated building envelopes. Identification of poorly insulated building envelopes is still a challenge. Nowadays, remote sensing equipment has become increasingly inexpensive and accessible. This paper evaluates the potential of using unmanned aerial vehicles (UAVs) carried equipment for quantitative analysis of the thermal properties of building envelopes. A comprehensive uncertainty analysis of the U-value measurement is conducted. In the uncertainty budget, an error in temperature measurement with IR camera contributes the largest share of uncertainty. Additionally, IRT measurements are compared with the heat flux meter (HFM) method.

Multifunctionalization of fiber-reinforced composites, especially by adding energy storage capabilities, is a promising approach to realize lightweight structural energy storages for future transport vehicles. Compared to conventional energy storage systems, energy density can be increased by reducing parasitic masses of non-energy-storing components and by benefitting from the composite meso- and microarchitectures. In this paper, the most relevant existing approaches towards multifunctional energy storages are reviewed and subdivided into five groups by distinguishing their degree of integration and their scale of multifunctionalization. By introducing a modified range equation for battery-powered electric aircrafts, possible range extensions enabled by multifunctionalization are estimated. Furthermore, general and aerospace specific potentials of multifunctional energy storages are discussed. Representing an intermediate degree of structural integration, experimental results for a multifunctional energy-storing glass fiber-reinforced composite based on the ceramic electrolyte Li1.4Al0.4Ti1.6(PO4)3 are presented. Cyclic voltammetry tests are used to characterize the double-layer behavior combined with galvanostatic charge–discharge measurements for capacitance calculation. The capacitance is observed to be unchanged after 1500 charge–discharge cycles revealing a promising potential for future applications. Furthermore, the mechanical properties are assessed by means of four-point bending and tensile tests. Additionally, the influence of mechanical loads on the electrical properties is also investigated, demonstrating the storage stability of the composites.

This paper presents experimental measurement methods for the determination and evaluation of process related thermal residual stresses in fiber metal laminates. A cure monitoring system with fiber Bragg grating (FBG) sensors is used to measure the in-plane strains during processing of carbon fiber reinforced plastic (CFRP)-steel laminates. The simultaneous measurement captures the thermal expansion during the heating stages, the cure shrinkage, and the cooling thermal shrinkage. The results enable the characterization of the co-cure bonding process and the stress transfer between the metal and FRP-layers during the creation process. The residual strains, which are used for calculation of the residual stresses, are recorded at room temperature after manufacturing. In addition, an advanced method using FBG-sensors and the deflection of asymmetric hybrid specimens is developed to validate the gained residual stress data. Asymmetrical specimens are created by removing selected layers after cure. Quantitative evaluation is achieved by determination of their curvature and measuring the strain changes with the embedded FBG-sensors. For validation, the methods were successfully demonstrated on two different curing cycles with different resulting residual stress levels. The simultaneous strain measurement enables the investigation of stress development and delivers more in-depth process knowledge for further optimization of the manufacturing process.

The instrumented impact test is suitable for the determination of fracture mechanical parameters. In this paper the determination of the dynamic fracture toughness values in the lower ductile-to-brittle transition region is presented. The fracture toughness is determined at the onset of cleavage fracture and evaluated by the Master Curve (MC) concept. The MC concept allows to quantify the variation of fracture toughness with the temperature within the lower ductile-to-brittle transition region. Limit curves of fracture toughness for defined failure probabilities and a reference temperature can be determined using this method. This paper presents the application of the master curve concept to the reference temperature determination through the thickness of reactor pressure vessel (RPV) steel plate. The reference temperatures determined dynamic fracture toughness values (T 0 dy ) are compared with quasi-static reference temperatures (T 0 st ) and Charpy-V transition temperatures (TT). T 0 dy , T 0 st and TT increase from the surface to the middle of the RPV steel plate. Compared with T 0 st , the T 0 dy values are higher approximately 70 to 90 K.

Historically, many of the classical organic fluorescent dyes were developed as laser dyes and characterized and optimized in organic solvents. Since then, fluorescence has, however, found a vast range of applications in the life sciences in which the fluorophores are usually surrounded by water and not by organic solvents. The omnipresence of water in biomolecular fluorescence spectroscopy and imaging leads to some unwanted but nonetheless unavoidable consequences on the photophysical properties of the dyes, which may impact the quality and complicate quantitative interpretation of the experiments. This paper discusses and illustrates with examples two such water-induced phenomena, namely chromophore aggregation in water and fluorescence quenching by water, as well as some ways to overcome them.

A gas turbine model combustor for partially premixed flames was equipped with an optically accessible combustion chamber and operated with methane and air at atmospheric pressure, with a global equivalence ratio of 0.7 and a thermal power of 25 kW. At these conditions the combustor exhibited thermo-acoustic oscillations with a frequency of approximately 400 Hz. The flame behavior and its cyclic variations were investigated by laser Raman scattering for the simultaneous determination of the major species concentrations, temperature and mixture fraction. Additional information of the mean flow field and the flame shape was provided by particle image velocimetry and OH ∗ chemiluminescence imaging, respectively. Previously published results of phase-correlated mean values of this flame showed that the instability was sustained by the mechanism known as equivalence ratio fluctuations with convective delay. The current paper is focused on the characterization of the thermo-chemical state of the flame during the oscillation cycle. The mixture fraction varies considerably with spatial location and with the phase of the pressure oscillation and strong effects of turbulence–chemistry interaction are prevailing in the region close to burner mouth. Further, the effect of locally rich mixtures and elevated temperature on the local CO concentration level is shown.

The mechanical properties of porous thin films and perforated layers are affected by pore content, shape and arrangement. The experimental determination of the in-plane mechanical properties of such materials is challenging, yet reliable data are essential for materials development and component design. Analytical and numerical approaches therefore provide valuable, supplementary tools for evaluating the effect of porosity on the mechanical properties of such materials. The applicability of both the classical self-consistent method and the Mori–Tanaka approach to the estimation of the effective elastic properties of porous thin films and perforated layers is investigated in this paper. For generic model microstructures with various arrangements of pores, variable pore content and varying matrix Poisson’s ratio, the effective elastic properties predicted by the classical self-consistent method and by the Mori–Tanaka approach are quantitatively compared with results obtained by numerical experiments. Based upon this comparison, the range of validity of both the classical self-consistent method and the Mori–Tanaka approach with regard to the different arrangements of pores investigated is defined, and the deviation to be expected if critical values of pore content or inter-pore distance are exceeded and interactions between adjacent pores are occurring is assessed.

Recently, metal hydride composites (MHC) have been proposed which consist of a hydride forming metal alloy and a highly heat conduction secondary phase such as expanded natural graphite (ENG) in order to improve the thermal conductivity of metal hydride powder beds. However, only little data is available in the literature on the effects of extensive cycling on technically relevant properties of MHC. In this paper, hydrogenation characteristics, thermal conductivity and geometrical stability of Hydralloy® C5-based MHC were thoroughly investigated over 1000 cycles. The obtained results suggest that the MHC under study did not significantly alter their hydrogen uptake characteristics throughout cycling, despite the fact that their thermal conductivity decreased during the first 250 cycles but remained constant thereafter. Although the cylindrical MHC maintained their geometrical stability, radial cracks were detected after cycling. Based on these results, MHC are suitable for high-dynamic applications such as hydrogen storage or thermochemical devices.

Thermal energy storage is a key technology for the commercialization of solar thermal power plants. This paper gives an overview of a coupled system comprised of concrete regenerators and latent heat storages for direct steam generation, as developed by the German Aerospace Center. Methodologies for an effective transient numerical description of the heat conduction processes inside the single modules and in the whole storage system are presented and their validity is proven by experiments. The presented process has a nominal system pressure of 105.6/80.0 bar for charging/discharging; the corresponding boiling temperatures are 315/295°C. As storage material of the latent heat storage, sodium nitrate with a melting point of 305°C is applied. With the presented models, a prediction of the storage system's temperatures, capacities, and effectiveness is possible. As a result, the design of a 1000-MWhth storage system is presented.

In this paper the characteristics of small carbon nanotube (CNT) dipole antennas are investigated on the basis of the thin wire Hallén integral equation (IE). A surface impedance model for the CNT is adopted to account for the specific material properties resulting in a modified kernel function for the integral equation. A numerical solution for the IE gives the current distribution along the CNT. From the current distribution the antenna driving point impedance and the antenna efficiency are computed. The presented numerical examples demonstrate the strong dependence of the antenna characteristics on the used material and show the limitations of nanoscale antennas.

The design and synthesis of Janus nanoparticles has attracted great scientific interest in recent years. Novel optical, electronic, magnetic, and superficial properties emerge from their dimensions and unique morphology at the nanoscale. Additional properties emerge from the binary spatial distribution of functionalities on a single anisotropic nanoparticle, like amphiphilicity or new catalytic effects. As a result, Janus nanoparticles are highly versatile nanomaterials with great potential in different scientific and technological fields. In this paper, some of the advances in inorganic – inorganic and inorganic–organic Janus nanoparticles are highlighted. First, the main strategies followed to synthesize Janus nanoparticles are described. Second, some of the properties and applications of Janus nanoparticles are described in four different fields: interfaces and emulsions, biomedicine, catalysis, and molecular colloids and suprastructures.

In this paper some basic investigations about laser-induced contamination are reported. As contamination materials pure aromatic hydrocarbons (naphthalene and anthracene) were used. A particular focus of the tests was to investigate the impact of laser-induced contamination on damage threshold. Onset and evolution of deposit formation and damage were observed in-situ by laser-induced fluorescence and transmission monitoring. As optical samples uncoated fused silica substrates and AR and HR coated optics with different coating morphology, depending on coating process (e-beam, magnetron sputtering) were investigated. Ex-situ characterization of deposits and damage morphology was performed by differential interference contrast, fluorescence, and atomic force microscopy. The tests were run with pulsed UV light at 355 nm. Partial pressure of contamination material in the range of 10 -4 mbar induced a drastic reduction of laser damage threshold compared to values obtained without contamination.

The node-and-spacer approach is widely employed in crystal engineering to construct coordination polymers. It consists of self-assembly processes involving mononuclear cationic species and exo-dentate ligands. We enlarged this strategy using preformed homo- and heterometallic complexes as nodes. The presence of two or more metal ions within a node leads to novel network topologies, as well as to new properties, arising from the intra- and internode interactions. This paper reviews some representative examples of coordination polymers obtained in our laboratory and constructed from: i) binuclear alkoxo-bridged complexes; ii) heterometallic 3d-3d' and 3d-4f complexes.

This paper describes the synthesis and characterization of core-shell structures, based on SnO2 and TiO2, for use in dye-sensitized solar cells (DSC). Atomic layer deposition is employed to control and vary the thickness of the TiO2 shell. Increasing the TiO2 shell thickness to 2 nm improved the device performance of liquid electrolyte-based DSC from 0.7% to 3.5%. The increase in efficiency originates from a higher open-circuit potential and a higher short-circuit current, as well as from an improvement in the electron lifetime. SnO2-TiO2 core-shell DSC devices retain their photovoltage in darkness for longer than 500 seconds, demonstrating that the electrons are contained in the core material. Finally core-shell structures were used for solid-state DSC applications using the hole transporting material 2,2',7,7',-tetrakis(N, N-di-p-methoxyphenyl-amine)-9,9',-spirofluorene. Similar improvements in device performance were obtained for solid-state DSC devices.

This paper presents the numerical simulations and performance analysis of a 3D scramjet inlet with focus on the effects of sidewall compression and relaminarization. A well-validated �finite volume flow solver was used to simulate a scramjet inlet with a double ramp configuration for outer compression and varying degrees of sidewall compression. The computed wall pressure and heat transfer in the symmetry plane are in close agreement with the measurements and numerical results indicate that sidewall compression alters the inlet performance significantly. The effects of relaminarization over the expansion corner prior to the interior part of the inlet is isolated and studied in both experiment and simulation.

Lithium-Ionen-Akkumulatoren erobern nach und nach neue Anwendungen auserhalb der Konsumerelektronik. Damit einher gehen neue Anforderungen an diese Technologie. In diesem Beitrag werden die Materialien, Zelldesigns und verfahrenstechnischen Schritte beschrieben, mit denen die Zellen an die unterschiedlichen Anforderungen, wie z. B. die Elektromobilitat, Zwischenspeicherung von Strom aus erneuerbaren Quellen etc., angepasst werden konnen. Daruber hinaus soll ein Ausblick uber aktuelle Trends bei der Weiterentwicklung von Lithium-Akkumulatoren gegeben werden. Lithium ion secondary batteries are capturing step by step new fields of application outside consumer electronics. Therefore the lithium ion technology has to face new challenges. In this paper materials, cell designs and process technologies are described allowing the adaption of cells to the different requirements for use, e.g., in electro mobility, buffering of electric power from renewables etc. In addition, an outlook is given on current trends on further development of lithium rechargeable battery technology.

Aus energetischer und auch raumklimatischer Sicht sind thermisch aktivierte Betondecken sinnvoll. Eingesetzt in Verwaltungsbauten tritt aber ihr Nachteil in Erscheinung: Sie sind akustisch reflektierend. Ubliche Losungsansatze sind schallabsorbierende abgehangte Segel und Absorberbaffles oder grosflachig einbetonierte, warmeleitende Schallabsorber. Hier wird ein alternativer Ansatz vorgestellt und akustisch sowie thermisch beurteilt. Wenige Streifen Schallabsorber werden bundig und in periodischer Anordnung in die Betondecke betoniert. Fur die Berechnung des Schallabsorptionsspektrums wird ein schon vielfach publiziertes Modell (Rayleigh-Ansatz) verwendet. Es prognostiziert das Schallabsorptionsspektrum fur senkrechte Schallinzidenz gut; fur diffuse Schallinzidenz ist der Unterschied zur Hallraummessung vermutlich wegen des Kanteneffekts groser. Der Schallabsorptionsgrad der Konstruktion kann mittels geschickter Wahl der Streifengeometrie eingestellt werden und ist deutlich hoher als das Flachenmittel erwarten liese. Einerseits wird die thermische Effizienz bauteilbezogen uber einen Wirkungsgrad bestimmt, bei dem die Warmestrome der Decken mit Absorberstreifen zu einer unbehandelten Referenzdecke ins Verhaltnis gesetzt werden. Andererseits wird das Raumklima mithilfe eines Raummodells fur Buroraume im Massiv- und Leichtbau untersucht. Der Einfluss der Streifen (Absorberflachenanteil von 20 %) auf den thermischen Wirkungsgrad und das Raumklima ist gering. Es werden zwei Absorbermaterialien im Streifenansatz untersucht: offenzelliger Glasschaum und mikroperforierte Absorber aus Metall. Wahrend der Absorber aus Metall thermisch Vorteile zeigt, weist dessen Schallabsorptionsspektrum selbst bei hoher Flachenbelegung einen deutlich geringeren Schallabsorptionsgrad auf als z. B. offenzellige Glasschaumstreifen mit nur 20 % Deckenbelegung. Eine Demonstration in situ zeigt das Potential der periodischen Absorberstreifen. Jedoch ist der in diesem Demovorhaben gewahlte Weg, die Absorberstreifen in die Betondecken zu integrieren, noch verbesserungswurdig. Integrated sound absorption in thermally activated concrete ceilings – acoustic and thermal effectiveness of sound-absorber strips spaced at intervals. From the perspectives of energy as well as indoor climate, thermally activated concrete ceilings make sense. Used in office buildings, however, their drawback becomes apparent: they are acoustically reflective. The conventional approaches use sound-absorbing suspended sails and absorber baffles or heat-conducting sound absorbers embedded in large areas of the concrete. In this paper, an alternative approach is presented and is evaluated acoustically and thermally. A few strips of sound absorber, arranged at intervals, are mounted flush into the concrete ceiling. To calculate the sound-absorption spectrum, an already widely publicised model (the Rayleigh approach) is used. It predicts the sound-absorption spectrum for normal sound incidence very well. For diffuse sound incidence, the difference to reverberation chamber measurements is greater, presumably because of the edge effect. The sound- absorption coefficient of the design can be tuned by skilful choice of the strip geometry, and it is significantly higher than the expected average value for the surface. On the one hand, the thermal efficiency of the components is determined by comparing the heat fluxes in the ceilings with absorber strips to an untreated reference ceiling. On the other hand, the indoor climate is investigated using a room model for office rooms of both solid and lightweight constructions. The influence of the strips (proportion of absorber area 20 %) on the thermal efficiency and indoor climate is low. Two absorber materials are examined in the strip approach: open-cell foam glass and a micro-perforated metallic absorber. While the metallic absorber displays thermal advantages, its sound absorption spectrum – even at high surface-coverage proportions – exhibits a much lower absorption coefficient than, for example, open-cell foam glass strips with only 20 % ceiling coverage. A demonstration in situ shows the potential of the absorber strips spaced at intervals. However, the method chosen in this demonstration project to incorporate the absorber strip into the concrete ceilings needs to be improved.

International audience; The aim of this investigation was to compare the mechanical behaviour of lengthwise and plain sliced veneer of the species beech ( L.). Therefore, tension tests parallel and perpendicular to the grain were carried out. The results were evaluated using the variance analysis (ANOVA). As a result it can be stated that lengthwise sliced veneers exhibit significantly higher strength and better mechanical characteristics than plain sliced veneers. The checks parallel to the grain which occurred by manufacturing at that side of the veneer leaf which faces the cutting edge and which is stressed in tension are to be considered as reason therefore. In contrast to the tests parallel to the grain the modulus of elasticity perpendicular to the grain shows significantly lower values for lengthwise sliced veneers than for plain sliced veneers. Due to their higher strength values lengthwise sliced veneers are considered better base materials for engineered wood products than plain sliced veneers.

The effects of laser sintering parameters (laser power, scan speed and hatching space) and post sintering process (heating rate, sintering temperature and holding time) on the physical and mechanical properties of porcelain components have been investigated. The study has been carried out using the Taguchi's method for the experimental design. In the laser sintering process, lower laser energy density and higher hatching space will increase the final mechanical properties of the porcelain components. A stress relief principle has been put forward to explain the different influence of the factors. The appropriate laser sintering parameters are attained in this paper: laser power 50 W; scan speed 85 mm/s; and hatching space 0.6 mm. Sintering temperature has been determined to be the most important factor in the post sintering process. Appropriate sintering temperature for the laser sintered porcelain bodies is in the range of 1425–1475 °C regarding the mechanical properties of the porcelain components. The maximum bending strength, 34.0 ± 4.9 MPa, is reached.

International audience; Peripheral milling of wood with up milling and down milling techniques is very well known from a geometrical point of view. However, in processing anisotropic materials such as wood, these geometrical aspects imply relevant differences when machining. In fact, milling of anisotropic material leads to different cutting geometries when up- or down-milling and when increasing or decreasing the depth of cut resulting in different grain orientations depending on the adopted process. In this paper, tests performed when processing Douglas Fir with different depths of cut and grain orientations are described. The cutting forces were measured, and the dependence of the cutting forces with respect on the cutting geometry are analysed and discussed.

An experimental setup for the generation and investigation of periodic equivalence ratio oscillations in laminar premixed flames is presented. A special low-pressure burner was developed which generates stable flames in a wide pressure range down to 20 mbar and provides the possibility of rapid mixture fraction variations. The technical realization of the mixture fraction variations and the characteristics of the burner are described. 1D laser Raman scattering was applied to determine the temperature and concentration profiles of the major species through the flame front in correlation to the phase-angle of the periodic oscillation. OH* chemiluminescence was detected to qualitatively analyze the response of the flame to mixture fraction variations by changing shape and position. Exemplary results from a flame at p=69 mbar, forced at a frequency of 10 Hz, are shown and discussed. The experiments are part of a cooperative research project including the development of kinetic models and numerical simulation tools with the aim of a better understanding and prediction of periodic combustion instabilities in gas turbines. The focus of the current paper lies on the presentation of the experimental realization and the measuring techniques.

This paper reports on the design, fabrication and test of an integrated colloid micropropulsion system for spacecraft attitude control using the ionic liquid EMI-BF4 as fuel. The principle of operation of the thruster is identical to electrospray ionization. The objective of the project was to demonstrate the feasibility and operability of arrays of microfabricated capillary emitters with individual extractor electrodes. This design approach results in an identical electric field distribution from one capillary to the other, avoids crosstalk and therefore allows for a more finely modulated thrust control. Spraying tests with different thruster configurations were conducted under vacuum conditions. Tests were performed with different thruster configurations and starting voltages around 700 V were observed.

International audience; The aim of indentation analysis is to link indentation data, typically an indentation force vs. indentation depth curve, P–h, to meaningful mechanical properties of the indented material. While well established for time independent behavior, the presence of a time dependent behavior can strongly affect both the loading and the unloading responses. The paper presents a framework of viscoelastic indentation analysis based on the method of functional equations, developed by Lee and Radok [1960, The contact problem for viscoelastic bodies, J. Appl. Mech. 27, 438–444]. While the method is restricted to monotonically increasing contact areas, we show that it remains valid at the very beginning of the unloading phase as well. Based on this result, it is possible to derive closed form solutions following the classical procedure of functional formulations of viscoelasticity: (1) the identification of the indentation creep function, which is the indentation response to a Heaviside load; and (2) a convolution integral of the load history over the indentation creep function. This is shown here for a trapezoidal loading by a conical indenter on three linear isotropic viscoelastic materials with deviator creep: the 3-parameter Maxwell model, the 4-parameter Kelvin–Voigt model and the 5-parameter combined Kelvin–Voigt–Maxwell model. For these models, we derive closed form solutions that can be employed for the back-analysis of indentation results from the loading and holding period and for the definition of unloading time criteria that ensure that viscous effects are negligible in the unloading response.

This paper deals with the influence of matrix cracks on the failure mode of bimaterial systems and composite materials. In order to investigate such an influence, the stress field near a crack embedded into the more yielding material and propagating perpendicularly to the interface, has been analyzed by using systematic numerical simulations. Such analysis has shown that the crack propagation give rises to transversal stresses that can damage the reinforcing materials when this has low modulus, as glass fibers, or low transversal strength, such as carbon fibers. Moreover, the longitudinal stress concentration can damage the reinforcing material only if this has high stiffness, as in the case of aramid and carbon fibers. Also, the numerical results have permitted to implement simple formulas that allows the user an accurate evaluation of the SIF as well as to predict possible debonding or fiber splitting phenomena. Finally, the SIFs evaluated numerically have been corroborated by experimental tests carried out by using an efficient procedure based on RGB digital photoelasticity. © 2005 Elsevier Ltd. All rights reserved.

Silicone additives are a very widely used type of additive in coatings. Their main feature is the reduction of the surface tension of the liquid coating. Due to this very specific property they are successfully used to overcome surface defects like cratering, poor wetting and others. In addition to this, silicone additives can also enhance the surface slip of a coating, which can be used e.g. to improve the scratch resistance of the surface. The chemistry of the silicone additives and the relationship between chemistry and performance are discussed in this paper.

The present paper reports on basic investigations of the controlled reaction sintering of MoSi2-based materials, including particle reinforced composites. It is shown, that certain amounts of preformed silicide phase in the powder mixtures are useful to achieve closed porosity by pressureless sintering of green compacts. This partial phase formation of alphaMoSi(2) can already take place during the mechanical treatment of the elemental powder mixtures by milling. In this context the role of volume changes linked with the phase formations are discussed.

Biomedical microsystems attain to contact with environments like blood, ephitHelium and saline solutions therefore they need an encapsulation. Parylene seems to be a suitable polymer to cover the implants and protect them against moisture and aggressive environment. This paper describes the characterisation of Parylene C coatings and its possibilities to protect implants. Beside the encapsulation of biomedical microsystems the manufacturing of fexible electrodes and the cytotoxicity behavior of RIE etched Parylene layers was investigated.

When using the capacitive coupling voltage contrast (CCVC) for failure analysis of defect integrated circuits (IC) with oxide covered internal nodes, a second group of measurement errors additionally to the group of measurement errors in electron beam testing (EBT) at unpassivated IC can be noted. Thereby, the capacitive coupling error (CCE) and the capacitive coupling cross talk (CCCT) are of special interest because they determine the applicability of the CCVC and may not be reduced up to now. The aim of this paper is to verify experimentally both errors for a test structure and to give a measure for their reduction. A calibration procedure will be presented which allows a mathematical reduction of CCE and CCCT. The applicability of this calibration procedure will be verified experimentally even for test points in IC with multi-level interconnection