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In this study, the impact of different vibrational modes on the fluidization characteristics of cohesive micro- and nano-silica powder was examined. Fractional pressure drop, bed expansion measurements, and X-ray imaging were utilized to characterize the fluidization quality. The densities of the emulsion phase at the top and bottom of the column were quantified and compared, providing insights into the solid distribution within the fluidized bed. In the absence of vibration, neither powder could be fluidized within the considered range of superficial gas velocities. Vertical vibration was found to initiate fluidization for both powders. In contrast, elliptical vibration failed to overcome the channelling behavior when fluidizing the micro-powder. For nano-powder, combined channelling and powder compaction occurred when the bed was subjected to elliptical vibration. For the micro-powder, it was observed that bed homogeneity was independent of vertical vibration intensity but improved with increasing superficial gas velocity. For nano-powder, intensifying vertical vibration led to segregation, likely due to agglomerate densification. Furthermore, fractional pressure drop measurements proved to be a strong tool in assessing fluidization quality, providing insights that could not be attained by conventional indicators., ChemE/Product and Process Engineering, Sanitary Engineering

In this study, butanol, as an oxygenate additive and alumina as a nano metal particle, was mixed with pure gasoline. Different blends were tested, and operational tests were done on an engine with different engine speeds. Those additives were added to decrease air pollution due to the higher oxygen content of butanol, which can make combustion more complete, and nano metal additive, which has suitable potential to enhance engine performance, especially Brake Specific Fuel Consumption (BSFC). The results indicate that adding the additives mentioned above to the pure gasoline has led to an increase the engine performance. In this regard, the engine power has increased by 10% by adding alumina. Moreover, combining the base gasoline with additives enhances CO2 and reduces NOx and emissions of hydrocarbons. In this research, carbon monoxide was diminished by adding alcohol up to 50% in some conditions, and the emitted hydrocarbons through the atmosphere were declined by up to 20%. Moreover, optimization results showed that higher optimization is achieved when 5% of butanol and 1 g of alumina are used. Under these conditions, the results of CO, CO2, NOx and HC emissions were 1.099, 4.699, 113.9 and 77.5 ppm, respectively. © 2020 Elsevier Ltd

In this study, butanol, as an oxygenate additive and alumina as a nano metal particle, was mixed with pure gasoline. Different blends were tested, and operational tests were done on an engine with different engine speeds. Those additives were added to decrease air pollution due to the higher oxygen content of butanol, which can make combustion more complete, and nano metal additive, which has suitable potential to enhance engine performance, especially Brake Specific Fuel Consumption (BSFC). The results indicate that adding the additives mentioned above to the pure gasoline has led to an increase the engine performance. In this regard, the engine power has increased by 10% by adding alumina. Moreover, combining the base gasoline with additives enhances CO2 and reduces NOx and emissions of hydrocarbons. In this research, carbon monoxide was diminished by adding alcohol up to 50% in some conditions, and the emitted hydrocarbons through the atmosphere were declined by up to 20%. Moreover, optimization results showed that higher optimization is achieved when 5% of butanol and 1 g of alumina are used. Under these conditions, the results of CO, CO2, NOx and HC emissions were 1.099, 4.699, 113.9 and 77.5 ppm, respectively. © 2020 Elsevier Ltd

The widespread use of copper oxide nanoparticles (CuONPs) has dramatically increased their concentrations in soils and severely affected the health of soil organisms. The gut microbiota critically contributes to the metabolism and immune system of its host and is sensitive to environmental pollution. The toxic effect of CuONPs on the gut microbiota, especially in soil fauna, still needs further research. In the present study, a comprehensive toxicological test was performed to reveal the effects of CuONPs and their metal counterpart on the gut microbiota of soil collembolans using Illumina high throughput sequencing. Furthermore, the concomitant changes in the collembolans gut-associated antibiotic resistance genes (ARGs) and metabolism were investigated using high-throughput quantitative PCR and carbon and nitrogen stable isotope compositions. Both CuONPs and ionic copper (Cu) exposure disturbed the collembolan gut microbial community structure while only CuONPs reduced the gut microbial diversity. A total of 66 ARGs were detected in the collembolan guts, and CuONPs exposure induced a reduction in both diversity and abundance of ARGs. Additionally, CuONPs and ionic Cu exposure altered the C and N stable isotope compositions of the collembolans, indicating a change in their metabolism. Moreover, structural equation modeling indicated that 85.5% of the carbon stable isotope variations and 73.3% of the nitrogen stable isotope variations were explained by changes in Cu bioaccumulation and the gut microbiota. The results of the present study extend our knowledge regarding the comprehensive toxicity of metal oxide NPs on soil fauna. (C) 2020 Elsevier Ltd. All rights reserved.

Having an absorber layer thickness below 1 micrometre for a regular copper indium gallium di-selenide (CIGS) solar cell reduces the pathways for electron collection which lead to reduced recombination in the bulk absorber layer. Additionally, it reduces material costs and production time. Yet, having such a thin absorber reduces the cell efficiency significantly, mainly due to incomplete light absorption and high Mo/CIGS rear-surface recombination . The aim of this research is to implement some innovative rear surface modifications for a <500 nm thick CIGS absorber layer to reduce these effects: a passivation layer to reduce the back-surface recombination and point contact openings using nano-particles (NPs) (CdS, Ag, etc.) to create electrical contacts, with some NPs also improving the optical confinement. For example, one approach is to use a layer of thermally evaporated and uniformly deposited Ag, which is then annealed to create Ag NPs with typical diameters of 300 to 450 nm. An Al2O3 layer is used to passivate the Mo/CIGS rear surface which also prevents the NPs from completely dissolving into the absorber during the absorber deposition. The implementation of all these rear-surface modifications and their impact on the electrical performance of the CIGS solar cell will be discussed and analyzed in this paper. This work received funding from the European Union’s H2020 research and innovation program under grant agreement No. 715027., Electrical Engineering | Sustainable Energy Technology

Having an absorber layer thickness below 1 micrometre for a regular copper indium gallium di-selenide (CIGS) solar cell reduces the pathways for electron collection which lead to reduced recombination in the bulk absorber layer. Additionally, it reduces material costs and production time. Yet, having such a thin absorber reduces the cell efficiency significantly, mainly due to incomplete light absorption and high Mo/CIGS rear-surface recombination . The aim of this research is to implement some innovative rear surface modifications for a <500 nm thick CIGS absorber layer to reduce these effects: a passivation layer to reduce the back-surface recombination and point contact openings using nano-particles (NPs) (CdS, Ag, etc.) to create electrical contacts, with some NPs also improving the optical confinement. For example, one approach is to use a layer of thermally evaporated and uniformly deposited Ag, which is then annealed to create Ag NPs with typical diameters of 300 to 450 nm. An Al2O3 layer is used to passivate the Mo/CIGS rear surface which also prevents the NPs from completely dissolving into the absorber during the absorber deposition. The implementation of all these rear-surface modifications and their impact on the electrical performance of the CIGS solar cell will be discussed and analyzed in this paper. This work received funding from the European Union’s H2020 research and innovation program under grant agreement No. 715027., Electrical Engineering | Sustainable Energy Technology

New aggregation-induced emission (AIE) luminogens with high solid-state emission efficiencies are developed by adopting a benzo[b]thiophene S,S-dioxide core, and steric and electronic effects on the AIE property are elucidated. © The Royal Society of Chemistry.

New aggregation-induced emission (AIE) luminogens with high solid-state emission efficiencies are developed by adopting a benzo[b]thiophene S,S-dioxide core, and steric and electronic effects on the AIE property are elucidated. © The Royal Society of Chemistry.

New aggregation-induced emission (AIE) luminogens with high solid-state emission efficiencies are developed by adopting a benzo[b]thiophene S,S-dioxide core, and steric and electronic effects on the AIE property are elucidated. © The Royal Society of Chemistry.

In this era, the utilization of automobiles is increasing rapidly. So, it is a task for the automobile industries to yield well-ordered cooling system, which is actually responsible to carry waste heat of engine to atmosphere for effective working of an internal combustion engines. In this research, car radiator was tested by the water based Nano fluids to increase its heat transfer capacity and new experimental results were reported. Zinc Oxide nanofluids were prepared and tested by adding their nanoparticles in water with different volume fractions (0.1, 0.2, 0.3 and 0.4)%. Experimentally, effect of these concentrations were observed by varying a fluid flow rate from 4 liter per minute to 1 liter per minute and inlet temperature of fluid entering in radiator was kept constant at 80oC and enhancement in heat transfer was observed from 46% to 70% by using ZnO Nano Fluid having volumetric concentration 0.2%. Increase in volumetric concentration had shown the enhancement of heat transfer but up to 0.2% and it was seen that further increase in concentration was been reduced the heat transfer capacity.

Diese Arbeit untersucht Fe-Oxid-Systeme mit Hilfe einer Kombination aus Mikroskopie (LEEM, Röntgen PEEMs), Beugung (LEED) und Spektroskopie (XPS) und berichtet über die elektronenoptische Entwicklung adaptiver Optiken und Aberrationskorrekturen für einen elektrostatischen abbildenden Energieanalysator. Experimentell untersuchten wir Magnetit und Hämatit Dünnschichten. Ihre Kristallstruktur, Stöchiometrie sowie deren Oberflächenterminierung können durch spezielle Herstellungsverfahren eingestellt werden. Unter Ausnutzung der Echtzeit-Beobachtung mit Mikroskopie, Beugung und Spektroskopie untersuchten wir (a) die Oberflächenmodifikationen von Fe3O4 und α-Fe2O3-Dünnschichten durch Fe Ablagerung; (b) die reversible Phasenumwandlung Fe3O4 ↔ α-Fe2O3 unter verschiedenen Oxidationsbedingungen; (c) die Bildung der metastabilen γ-Fe2O3-Phase und (d) die Wechselwirkung von Fe3O4 und α-Fe2O3 Oberflächen mit unterstützten Pt-Nanopartikeln. Es wurde ein Algorithmus entwickelt, um den LEEM Bildkontrast für inhomogene 2D Oberflächen zu simulieren. Abschließend wird das Design eines Energiefilter-System vorgestellt, das in ein PEEM/LEEM Mikroskop der neuen Generation eingebaut werden wird. Das System basiert auf dem gleichen Abbildungsprinzip wie der magnetische Ω-Filter, der erfolgreich im aktuellen SMART Mikroskop eingesetzt wird. Das neue Instrument zielt auf die Verbesserung der Orts- und Energieauflösung im XPEEM (5 nm und 70 meV). Die Mehrzahl der möglichen Aberrationen zweiter Ordnung wird durch die intrinsische Symmetrie selbstkompensiert. Die Wirkung der anderen Aberrationen wird durch ein geeignetes Design der Verzögerungs- und Beschleunigungsoptiken kombiniert mit einer optimierten Passenergie reduziert. Darüber hinaus kompensieren zusätzliche Hexapole die restlichen dominierenden Aberrationen, wodurch eine Orts- und Energieauflösung besser als 2 nm bzw. 75 meV erreicht wird., This work presents the investigation of Fe-oxide systems, combining microscopy (LEEM, X-PEEM), diffraction (LEED) and spectroscopy (XPS), and the electron-optical development of adaptive optics and aberration corrections for an electrostatic imaging energy analyzer. Experimentally, we studied magnetite (Fe3O4) and hematite (α-Fe2O3) thin films. Their crystal structure, stoichiometry as well as their surface termination can be tuned by special preparation procedures. Taking advantage of real time observation with microscopy, diffraction and spectroscopy, we investigated (a) the surface modifications of Fe3O4 and α-Fe2O3 thin films by Fe deposition; (b) the reversible phase transformation Fe3O4 ↔ α-Fe2O3 under different oxidation conditions; (c) the formation of the metastable γ-Fe2O3 phase and (d) the interaction of Fe3O4 and α-Fe2O3 surfaces with supported Pt nanoparticles . An algorithm was developed to simulate the LEEM image contrast for inhomogeneous 2D surfaces. The possible application to experimental data and the limitation will be discussed. Finally, the design of an energy filtering system is presented, which will be implemented in a new generation PEEM/LEEM microscope. The system bases on the same imaging principle as the magnetic Ω-filter, successfully implemented in the actual SMART microscope. The new instrument aims for the improvement of lateral and energy resolution in X-PEEM (5 nm and 70 meV, respectively). The majority of the possible second order aberrations are self-compensated by intrinsic symmetry. The effect of the other aberrations is reduced by an adequate design for the deceleration-acceleration optics in combination with optimized pass energy. Furthermore, additional hexapole multipoles compensate for the residual dominating aberrations, yielding in the lateral resolution and energy resolution better than 2 nm and 75 meV, respectively.

In this era, the utilization of automobiles is increasing rapidly. So, it is a task for the automobile industries to yield well-ordered cooling system, which is actually responsible to carry waste heat of engine to atmosphere for effective working of an internal combustion engines. In this research, car radiator was tested by the water based Nano fluids to increase its heat transfer capacity and new experimental results were reported. Zinc Oxide nanofluids were prepared and tested by adding their nanoparticles in water with different volume fractions (0.1, 0.2, 0.3 and 0.4)%. Experimentally, effect of these concentrations were observed by varying a fluid flow rate from 4 liter per minute to 1 liter per minute and inlet temperature of fluid entering in radiator was kept constant at 80oC and enhancement in heat transfer was observed from 46% to 70% by using ZnO Nano Fluid having volumetric concentration 0.2%. Increase in volumetric concentration had shown the enhancement of heat transfer but up to 0.2% and it was seen that further increase in concentration was been reduced the heat transfer capacity.

In this era, the utilization of automobiles is increasing rapidly. So, it is a task for the automobile industries to yield well-ordered cooling system, which is actually responsible to carry waste heat of engine to atmosphere for effective working of an internal combustion engines. In this research, car radiator was tested by the water based Nano fluids to increase its heat transfer capacity and new experimental results were reported. Zinc Oxide nanofluids were prepared and tested by adding their nanoparticles in water with different volume fractions (0.1, 0.2, 0.3 and 0.4)%. Experimentally, effect of these concentrations were observed by varying a fluid flow rate from 4 liter per minute to 1 liter per minute and inlet temperature of fluid entering in radiator was kept constant at 80oC and enhancement in heat transfer was observed from 46% to 70% by using ZnO Nano Fluid having volumetric concentration 0.2%. Increase in volumetric concentration had shown the enhancement of heat transfer but up to 0.2% and it was seen that further increase in concentration was been reduced the heat transfer capacity.

In this era, the utilization of automobiles is increasing rapidly. So, it is a task for the automobile industries to yield well-ordered cooling system, which is actually responsible to carry waste heat of engine to atmosphere for effective working of an internal combustion engines. In this research, car radiator was tested by the water based Nano fluids to increase its heat transfer capacity and new experimental results were reported. Zinc Oxide nanofluids were prepared and tested by adding their nanoparticles in water with different volume fractions (0.1, 0.2, 0.3 and 0.4)%. Experimentally, effect of these concentrations were observed by varying a fluid flow rate from 4 liter per minute to 1 liter per minute and inlet temperature of fluid entering in radiator was kept constant at 80oC and enhancement in heat transfer was observed from 46% to 70% by using ZnO Nano Fluid having volumetric concentration 0.2%. Increase in volumetric concentration had shown the enhancement of heat transfer but up to 0.2% and it was seen that further increase in concentration was been reduced the heat transfer capacity.

In this era, the utilization of automobiles is increasing rapidly. So, it is a task for the automobile industries to yield well-ordered cooling system, which is actually responsible to carry waste heat of engine to atmosphere for effective working of an internal combustion engines. In this research, car radiator was tested by the water based Nano fluids to increase its heat transfer capacity and new experimental results were reported. Zinc Oxide nanofluids were prepared and tested by adding their nanoparticles in water with different volume fractions (0.1, 0.2, 0.3 and 0.4)%. Experimentally, effect of these concentrations were observed by varying a fluid flow rate from 4 liter per minute to 1 liter per minute and inlet temperature of fluid entering in radiator was kept constant at 80oC and enhancement in heat transfer was observed from 46% to 70% by using ZnO Nano Fluid having volumetric concentration 0.2%. Increase in volumetric concentration had shown the enhancement of heat transfer but up to 0.2% and it was seen that further increase in concentration was been reduced the heat transfer capacity.

The luminescent nanoparticles with Eu(III) ions are reported. Standard nanoparticles are prepared by the reaction of europium chloride with dpp (diphenylphospinic acid) joint ligands. The size-controlled nanoparticles are synthesized by the reaction of Eu(hfa)3(H2O)2 (hfa: hexafluoroacetylacetonate) with bidentate dpbp ligands (dpbp: 4,4'-bis(diphenylphosphoryl)biphenyl) and monodentate ligands (TPPO: triphenylphosphine oxide). Their particle sizes were characterized using TEM and dynamic light scattering (DLS) measurements. Their luminescence properties were estimated by the emission spectra and lifetimes.

The luminescent nanoparticles with Eu(III) ions are reported. Standard nanoparticles are prepared by the reaction of europium chloride with dpp (diphenylphospinic acid) joint ligands. The size-controlled nanoparticles are synthesized by the reaction of Eu(hfa)3(H2O)2 (hfa: hexafluoroacetylacetonate) with bidentate dpbp ligands (dpbp: 4,4'-bis(diphenylphosphoryl)biphenyl) and monodentate ligands (TPPO: triphenylphosphine oxide). Their particle sizes were characterized using TEM and dynamic light scattering (DLS) measurements. Their luminescence properties were estimated by the emission spectra and lifetimes.

This study investigated the durability properties of concrete containing nano-silica at dosages of 0.3% and 0.9%, respectively. Due to the nano-filler effect and the pozzolanic reaction, the microstructure became more homogeneous and less porous, especially at the interfacial transition zone (ITZ), which led to reduced permeability. Tests on the durability properties verified the beneficial effects of nano-silica. The channels for harmful agents through the cement composites were partially filled and blocked. The pore size distribution also indicated that the large capillary pores were refined by the nano-silica, due to the combined contribution of the nano-filler effect and the pozzolanic reaction.

In this preliminary study, we demonstrate an environmentally friendly process for the green synthesis of gold nanometre scale particles using the leaf extract from an indigenous Australian plant Eucalyptus macrocarpa as both the stabilising agent and the reducing agent. The synthesis process is straightforward, clean and non-toxic. It also has the advantages of being performed at room temperature and does not need complex processing equipment. Formation of the gold nanometre sized particles was confirmed and characterised by UV-visible spectroscopy, X-ray diffraction, transmission electron microscopy and field emission scanning electron microscopy. The antibacterial activity of the synthesised gold particles was also quantified using the sensitivity method of Kirby–Bauer.

We investigated the effect of the metal work-function and doping concentration on the barrier height of Ni-contacts with embedded nano-particles (NPs) on 4H-SiC surfaces. Both n-type epitaxial layers with N-D=1x10(16) cm(-3), and layers doped by phosphorus implantation to a doping concentration of similar to 1x10(19) cm(-3) are used. The barrier height is reduced with increasing doping concentration and the silver (Ag) nano-particles (R similar to 18.5 nm) further enhance the local electric field of the electrical contacts to 4H-SiC in comparison to gold (Au) nano-particles (R similar to 20.2 nm). In the case of ion-implanted samples, the barrier height of the fabricated SiC diode structures with embedded Ag-NPs was significantly reduced by similar to 0.09 eV and similar to 0.25 eV compared to the samples with Au-NPs and the sample without NPs, respectively., QC 20150629

This work presents a comprehensive characterization of the frequency dependence of the effective complex permittivity of bundled carbon nanotubes considering different densities over a broadband of frequencies from 10 MHz to 50 GHz using only one measurement setup. The extraction technique is based on rigorous modeling of coaxial and circular discontinuities using mode matching technique in conjunction with inverse optimization method to map the simulated scattering parameters to those measured by vector network analyzer. The dramatic values of complex permittivity obtained at low frequencies are physically explained by the percolation theory. The effective permittivity of a mixture of nano-particles of alumina and carbon nanotubes versus frequency and packing density is studied to verify the previously obtained phenomenon.

A Spark Discharge Generator is a versatile device which can be used to generate nanoparticles from any two conducting sources. The device constructed during this thesis project was to make metallic mono-disperse aerosol nanoparticles towards applications in catalysis and nanowire growth. The operating principle is two electrodes separated by a gap with an applied voltage above the discharge voltage. This high potential creates an ionization channel and a spark is discharged between the two electrodes causing a high local temperature on the ends of the electrodes which causes thermal evaporation of the material into the surrounding gas. These initial particles with sizes on the atomic scale collide and adhere by a process called coagulation creating larger nanoparticles which may then be filtered, reshaped, counted, and deposited. A theoretical introduction is presented, a description of the components is included, some techniques for calibration of the device are described, and initial data is shown.

The area of nanotechnology is one of the most active fields in science today. It is often seen as the area that could lead to substantial progress in terms of finding new materials with new properties. In this respect, silicon nano-particles are found to be greatly attractive because of their significant technological implications. Considering different areas of research, the energy production, conversion and storage processes are definitely among the most important topics to be studied by science. The reason for that lies in the significant and immediate consequences of their related technology on the current society. Silicon has received a great interest in the energy storage field and is, in fact, considered as one the most promising chemical element for energy storage in modern electrochemical devices due to the fact that it can alloy with lithium. In this respect, energy storage based on lithium chemistry is one of the most advanced electrochemical system in terms of specific power and energy density. Accordingly, Li-ion batteries could be significantly improved in terms of volumetric and gravimetric energy density by using silicon as a negative electrode material. The aim of the present thesis is to find a complete pathway for the silicon nano-particles, from their synthesis to their final designed application: a negative electrode for Li-ion batteries. Since no conventional methods to produce silicon nano-particles have been already established, several synthesis routes have been explored: Electrochemical Etching, Spark Discharge Generation and Laser assisted Chemical Vapor Pyrolisys, respectively. In Chapter 2, the anodic dissolution of a p-type silicon wafer in a HF solution is discussed. Despite the fact that the reaction mechanism is rather complicated and involves many different physical parameters, electrochemical etching offers a simple way to produce porous silicon layers, which can be detached and fragmented into small nano-particles by means of soni, DelftChemTech, Applied Sciences

To investigate the diffusion behavior of Tl ions, glass was immersed in TlNO3–KNO3 molten salt at 753 K for various lengths of time. The Tl ions embedded in the glass were then reduced to metallic Tl nano-particles by hydrogen at 803 K for 1 h. The depth of the ion exchange layer down to about 140 µm in the glass was found to be proportional to a square root of the length of immersion time. It was suggested that the ion exchange process is controlled by the diffusion of Tl ions from the surface to the inside. Reduction of Tl ions to metallic Tl with the hydrogen gas occurred only at the surface down to 4 µm. The concentration profile of the metallic Tl is discussed by nucleation-nucleus growth and the diffusion of Tl ions from deeper areas.

To investigate the diffusion behavior of Tl ions, glass was immersed in TlNO3–KNO3 molten salt at 753 K for various lengths of time. The Tl ions embedded in the glass were then reduced to metallic Tl nano-particles by hydrogen at 803 K for 1 h. The depth of the ion exchange layer down to about 140 µm in the glass was found to be proportional to a square root of the length of immersion time. It was suggested that the ion exchange process is controlled by the diffusion of Tl ions from the surface to the inside. Reduction of Tl ions to metallic Tl with the hydrogen gas occurred only at the surface down to 4 µm. The concentration profile of the metallic Tl is discussed by nucleation-nucleus growth and the diffusion of Tl ions from deeper areas.

A Spark Discharge Generator is a versatile device which can be used to generate nanoparticles from any two conducting sources. The device constructed during this thesis project was to make metallic mono-disperse aerosol nanoparticles towards applications in catalysis and nanowire growth. The operating principle is two electrodes separated by a gap with an applied voltage above the discharge voltage. This high potential creates an ionization channel and a spark is discharged between the two electrodes causing a high local temperature on the ends of the electrodes which causes thermal evaporation of the material into the surrounding gas. These initial particles with sizes on the atomic scale collide and adhere by a process called coagulation creating larger nanoparticles which may then be filtered, reshaped, counted, and deposited. A theoretical introduction is presented, a description of the components is included, some techniques for calibration of the device are described, and initial data is shown.

The directivities of the fields radiated by a variety of cylindrical and spherical active coated nano-particles, which are excited by their respective sources of illumination at optical frequencies, are investigated. Particular attention is devoted to the influence of the source location and optical gain constant on the directivities. While significant variations in the directivities are realized in the cylindrical cases for different source locations within and slightly outside the nano-particles and values of the optical gain constant, the corresponding spherical cases exhibit negligible differences.

The area of nanotechnology is one of the most active fields in science today. It is often seen as the area that could lead to substantial progress in terms of finding new materials with new properties. In this respect, silicon nano-particles are found to be greatly attractive because of their significant technological implications. Considering different areas of research, the energy production, conversion and storage processes are definitely among the most important topics to be studied by science. The reason for that lies in the significant and immediate consequences of their related technology on the current society. Silicon has received a great interest in the energy storage field and is, in fact, considered as one the most promising chemical element for energy storage in modern electrochemical devices due to the fact that it can alloy with lithium. In this respect, energy storage based on lithium chemistry is one of the most advanced electrochemical system in terms of specific power and energy density. Accordingly, Li-ion batteries could be significantly improved in terms of volumetric and gravimetric energy density by using silicon as a negative electrode material. The aim of the present thesis is to find a complete pathway for the silicon nano-particles, from their synthesis to their final designed application: a negative electrode for Li-ion batteries. Since no conventional methods to produce silicon nano-particles have been already established, several synthesis routes have been explored: Electrochemical Etching, Spark Discharge Generation and Laser assisted Chemical Vapor Pyrolisys, respectively. In Chapter 2, the anodic dissolution of a p-type silicon wafer in a HF solution is discussed. Despite the fact that the reaction mechanism is rather complicated and involves many different physical parameters, electrochemical etching offers a simple way to produce porous silicon layers, which can be detached and fragmented into small nano-particles by means of soni, DelftChemTech, Applied Sciences

This paper deals with gold, which is described as a chemical element. Special attention is paid to its physical-chemical properties and, furthermore, where or in what form it can be found in nature. We discuss the role it has played through history and we inform how gold has been developed to the level it has reached today's value. Still more, when gold is broken into nanoparticles, this form could be highly useful for a wide range of processes, including general nanotechnology, electronics manufacturing and the synthesizing of different functional materials. It is important that we know that gold is also used in industry in many engineering applications (contacts in micro-electronics) and medicine (dental alloys, implants).

The directivities of the fields radiated by a variety of cylindrical and spherical active coated nano-particles, which are excited by their respective sources of illumination at optical frequencies, are investigated. Particular attention is devoted to the influence of the source location and optical gain constant on the directivities. While significant variations in the directivities are realized in the cylindrical cases for different source locations within and slightly outside the nano-particles and values of the optical gain constant, the corresponding spherical cases exhibit negligible differences.

The goal of this work is the evaluation of nanoscaled reinforcements; in particular nanodiamonds (NDs) and carbon nanotubes (CNTs) on properties of titanium matrix composites (TiMMCs). By using nano sized materials as reinforcement in TiMMCs, superior mechanical and physical properties can be expected. Additionally, titanium powder metallurgy (P/M) offers the possibility of changing the reinforcement content in the matrix within a very wide range. In this work, TiMMCs have been produced from titanium powder (Grade 4). The manufacturing of the composites was done by hot pressing, followed by the characterisation of the TiMMCs. The Archimedes density, hardness and oxygen content of the specimens in addition to the mechanical properties were compared and reported in this work. Moreover, XRD analysis and SEM observations revealed in situ formed titanium carbide (TiC) phase after hot pressing in TiMMCs reinforced with NDs and CNTs, at 900 °C and 1100 °C respectively. The strengthening effect of NDs was more significant since its distribution was more homogeneous in the matrix.

The performance of modified polyvinylidene fluoride (PVDF) membrane in oilfield wastewater treatment was investigated. Oil content, suspended solids (SS), turbidity and total organic carbon (TOC) of the stable effluents were analyzed. Moreover, the fouling mitigation was quantitatively evaluated from the view of filtration resistances. In addition, fouled membranes were washed by the chemical method and it was found that the flux recovery ratio of the modified membrane was higher. The experimental results indicated that the modification improved PVDF membrane flux and anti-fouling ability without sacrificing the performances in oilfield wastewater treatment. © 2011 IEEE.

The performance of modified polyvinylidene fluoride (PVDF) membrane in oilfield wastewater treatment was investigated. Oil content, suspended solids (SS), turbidity and total organic carbon (TOC) of the stable effluents were analyzed. Moreover, the fouling mitigation was quantitatively evaluated from the view of filtration resistances. In addition, fouled membranes were washed by the chemical method and it was found that the flux recovery ratio of the modified membrane was higher. The experimental results indicated that the modification improved PVDF membrane flux and anti-fouling ability without sacrificing the performances in oilfield wastewater treatment. © 2011 IEEE.

The goal of this work is the evaluation of nanoscaled reinforcements; in particular nanodiamonds (NDs) and carbon nanotubes (CNTs) on properties of titanium matrix composites (TiMMCs). By using nano sized materials as reinforcement in TiMMCs, superior mechanical and physical properties can be expected. Additionally, titanium powder metallurgy (P/M) offers the possibility of changing the reinforcement content in the matrix within a very wide range. In this work, TiMMCs have been produced from titanium powder (Grade 4). The manufacturing of the composites was done by hot pressing, followed by the characterisation of the TiMMCs. The Archimedes density, hardness and oxygen content of the specimens in addition to the mechanical properties were compared and reported in this work. Moreover, XRD analysis and SEM observations revealed in situ formed titanium carbide (TiC) phase after hot pressing in TiMMCs reinforced with NDs and CNTs, at 900 °C and 1100 °C respectively. The strengthening effect of NDs was more significant since its distribution was more homogeneous in the matrix.

The goal of this work is the evaluation of nanoscaled reinforcements; in particular nanodiamonds (NDs) and carbon nanotubes (CNTs) on properties of titanium matrix composites (TiMMCs). By using nano sized materials as reinforcement in TiMMCs, superior mechanical and physical properties can be expected. Additionally, titanium powder metallurgy (P/M) offers the possibility of changing the reinforcement content in the matrix within a very wide range. In this work, TiMMCs have been produced from titanium powder (Grade 4). The manufacturing of the composites was done by hot pressing, followed by the characterisation of the TiMMCs. The Archimedes density, hardness and oxygen content of the specimens in addition to the mechanical properties were compared and reported in this work. Moreover, XRD analysis and SEM observations revealed in situ formed titanium carbide (TiC) phase after hot pressing in TiMMCs reinforced with NDs and CNTs, at 900 °C and 1100 °C respectively. The strengthening effect of NDs was more significant since its distribution was more homogeneous in the matrix.

The goal of this work is the evaluation of nanoscaled reinforcements; in particular nanodiamonds (NDs) and carbon nanotubes (CNTs) on properties of titanium matrix composites (TiMMCs). By using nano sized materials as reinforcement in TiMMCs, superior mechanical and physical properties can be expected. Additionally, titanium powder metallurgy (P/M) offers the possibility of changing the reinforcement content in the matrix within a very wide range. In this work, TiMMCs have been produced from titanium powder (Grade 4). The manufacturing of the composites was done by hot pressing, followed by the characterisation of the TiMMCs. The Archimedes density, hardness and oxygen content of the specimens in addition to the mechanical properties were compared and reported in this work. Moreover, XRD analysis and SEM observations revealed in situ formed titanium carbide (TiC) phase after hot pressing in TiMMCs reinforced with NDs and CNTs, at 900 °C and 1100 °C respectively. The strengthening effect of NDs was more significant since its distribution was more homogeneous in the matrix.

The performance of modified polyvinylidene fluoride (PVDF) membrane in oilfield wastewater treatment was investigated. Oil content, suspended solids (SS), turbidity and total organic carbon (TOC) of the stable effluents were analyzed. Moreover, the fouling mitigation was quantitatively evaluated from the view of filtration resistances. In addition, fouled membranes were washed by the chemical method and it was found that the flux recovery ratio of the modified membrane was higher. The experimental results indicated that the modification improved PVDF membrane flux and anti-fouling ability without sacrificing the performances in oilfield wastewater treatment. © 2011 IEEE.

The goal of this work is the evaluation of nanoscaled reinforcements; in particular nanodiamonds (NDs) and carbon nanotubes (CNTs) on properties of titanium matrix composites (TiMMCs). By using nano sized materials as reinforcement in TiMMCs, superior mechanical and physical properties can be expected. Additionally, titanium powder metallurgy (P/M) offers the possibility of changing the reinforcement content in the matrix within a very wide range. In this work, TiMMCs have been produced from titanium powder (Grade 4). The manufacturing of the composites was done by hot pressing, followed by the characterisation of the TiMMCs. The Archimedes density, hardness and oxygen content of the specimens in addition to the mechanical properties were compared and reported in this work. Moreover, XRD analysis and SEM observations revealed in situ formed titanium carbide (TiC) phase after hot pressing in TiMMCs reinforced with NDs and CNTs, at 900 °C and 1100 °C respectively. The strengthening effect of NDs was more significant since its distribution was more homogeneous in the matrix.

The thin film pressure balance (TFPB) technique were used to study the stability of single foam films produced in the presence of n-alkyl polyoxyethylene (CnEOm) homologues. The results showed that films thin faster than predicted by the classical DLVO theory, which considers contributions from the van der Waals-dispersion and double-layer forces to the disjoining pressure of the film. The discrepancy may be attributed to the presence of hydrophobic force, the magnitude of which has been estimated using the Reynolds lubrication approximation. It has been found that the attractive hydrophobic force was substantially larger than the attractive van der Waals force, which may explain the faster film thinning kinetics. With a given non-ionic surfactant, the hydrophobic force decreased with increasing surfactant concentration, which explained the slower kinetics observed at higher concentrations and hence the increased foam stability. At concentrations where the hydrophobic force became comparable to or smaller than the van der Waals force, the foam films were stabilized by the increased elasticity of the foam films. The film elasticity of the surfactant solutions were measured using the oscillating drop analysis technique at different frequencies. The measurements were conducted in the presence of CnEOm surfactants with n=10-14 and m=4-8, and the results were analyzed using the Lucassen and van den Tempel model (1972). There was a reasonable fit between the experiment and the model predictions when using the values of the Gibbs elasticity calculated from the Wang and Yoon model (2006). From this exercise, it was possible to determine the diffusion coefficients (D) of the CnEOm surfactants. The D values obtained for CnEOm surfactants were in the range of 2.5x10-10 to 6x10-9 m2s-1, which are in general agreement with those reported in the literature for other surfactants. The diffusion coefficient decreased with increasing alkyl chain length (n) and increased with increasi

The thin film pressure balance (TFPB) technique were used to study the stability of single foam films produced in the presence of n-alkyl polyoxyethylene (CnEOm) homologues. The results showed that films thin faster than predicted by the classical DLVO theory, which considers contributions from the van der Waals-dispersion and double-layer forces to the disjoining pressure of the film. The discrepancy may be attributed to the presence of hydrophobic force, the magnitude of which has been estimated using the Reynolds lubrication approximation. It has been found that the attractive hydrophobic force was substantially larger than the attractive van der Waals force, which may explain the faster film thinning kinetics. With a given non-ionic surfactant, the hydrophobic force decreased with increasing surfactant concentration, which explained the slower kinetics observed at higher concentrations and hence the increased foam stability. At concentrations where the hydrophobic force became comparable to or smaller than the van der Waals force, the foam films were stabilized by the increased elasticity of the foam films. The film elasticity of the surfactant solutions were measured using the oscillating drop analysis technique at different frequencies. The measurements were conducted in the presence of CnEOm surfactants with n=10-14 and m=4-8, and the results were analyzed using the Lucassen and van den Tempel model (1972). There was a reasonable fit between the experiment and the model predictions when using the values of the Gibbs elasticity calculated from the Wang and Yoon model (2006). From this exercise, it was possible to determine the diffusion coefficients (D) of the CnEOm surfactants. The D values obtained for CnEOm surfactants were in the range of 2.5x10-10 to 6x10-9 m2s-1, which are in general agreement with those reported in the literature for other surfactants. The diffusion coefficient decreased with increasing alkyl chain length (n) and increased with increasi

The electronic and geometrical structure of free neutral clusters and liquids have been studied using synchrotron-radiation based photoelectron and Auger electron spectroscopy in combination with lineshape modeling. A novel experimental setup has been developed for studies of liquids, based on the liquid microjet technique. Theoretical lineshapes have been computed using both classical (molecular dynamics) and quantum mechanical (mainly density functional theory) methods. Clusters are finite ensembles of atoms or molecules, ranging in size from a few to several thousand atoms. Apart from being fundamentally interesting, clusters are also promising as building blocks for nano-technology. In this thesis results are presented for rare-gas and molecular clusters, ranging from weakly van-deer-Waals bonded to hydrogen bonded. It is shown that the combination of core-level photoelectron spectroscopy (XPS) and lineshape modeling can be used to estimate the sizes of clusters. A model for treating the effect of inter-molecular nuclear relaxation upon ionization is proposed. The structure of single-component molecular clusters are investigated by molecular dynamics simulations, validated against XPS data. Finally, the radial structure of a two-component molecular cluster is investigated by XPS. Liquids have been studied for centuries, but still many questions remain regarding the microscopic properties. With the recent development of the liquid microjet technique, new insight into the atomic structure can be obtained. In this thesis we study aqueous solutions using photoelectron and Auger electron spectroscopy (AES). We investigate the structure of surface active molecules by XPS, study the Auger decay after core-level ionization in aqueous potassium chloride (KCl), and follow the changes in molecular structure of glycine as a function of pH.

The electronic and geometrical structure of free neutral clusters and liquids have been studied using synchrotron-radiation based photoelectron and Auger electron spectroscopy in combination with lineshape modeling. A novel experimental setup has been developed for studies of liquids, based on the liquid microjet technique. Theoretical lineshapes have been computed using both classical (molecular dynamics) and quantum mechanical (mainly density functional theory) methods. Clusters are finite ensembles of atoms or molecules, ranging in size from a few to several thousand atoms. Apart from being fundamentally interesting, clusters are also promising as building blocks for nano-technology. In this thesis results are presented for rare-gas and molecular clusters, ranging from weakly van-deer-Waals bonded to hydrogen bonded. It is shown that the combination of core-level photoelectron spectroscopy (XPS) and lineshape modeling can be used to estimate the sizes of clusters. A model for treating the effect of inter-molecular nuclear relaxation upon ionization is proposed. The structure of single-component molecular clusters are investigated by molecular dynamics simulations, validated against XPS data. Finally, the radial structure of a two-component molecular cluster is investigated by XPS. Liquids have been studied for centuries, but still many questions remain regarding the microscopic properties. With the recent development of the liquid microjet technique, new insight into the atomic structure can be obtained. In this thesis we study aqueous solutions using photoelectron and Auger electron spectroscopy (AES). We investigate the structure of surface active molecules by XPS, study the Auger decay after core-level ionization in aqueous potassium chloride (KCl), and follow the changes in molecular structure of glycine as a function of pH.

A Novel synthesis method based on the behaviour and effect of the addition of chloride and sulphate for spheroidization of the structure of rare earth-oxide e.g. and were prepared from combustion synthesis at a temperature of. The compounds were later doped with at various percentages and calcined at for 4 hours. The crystallites size and the thermal stability of the doped powder were determined with X-ray and thermogravimetry respectively. Scanning Electron Microscopy was finally used to determine the morphology of the novel rare earth-oxides calcined at. Secondly, another set of doped compound were also calcined at a various temperatures for 4 hours and its crystallites size, thermal stability and morphology were also determined with X-ray, Thermogravimetry and Scanning Electron Microscopy. Finally, conclusion was drawn based on how the crystallites size changed with regard to percentage of at the calcinations temperature of and also at a various calcination temperatures with a fixed percentage of the doped. Lastly, the same techniques were applied to gadolinium oxide., Validerat; 20101217 (root)

The electronic and geometrical structure of free neutral clusters and liquids have been studied using synchrotron-radiation based photoelectron and Auger electron spectroscopy in combination with lineshape modeling. A novel experimental setup has been developed for studies of liquids, based on the liquid microjet technique. Theoretical lineshapes have been computed using both classical (molecular dynamics) and quantum mechanical (mainly density functional theory) methods. Clusters are finite ensembles of atoms or molecules, ranging in size from a few to several thousand atoms. Apart from being fundamentally interesting, clusters are also promising as building blocks for nano-technology. In this thesis results are presented for rare-gas and molecular clusters, ranging from weakly van-deer-Waals bonded to hydrogen bonded. It is shown that the combination of core-level photoelectron spectroscopy (XPS) and lineshape modeling can be used to estimate the sizes of clusters. A model for treating the effect of inter-molecular nuclear relaxation upon ionization is proposed. The structure of single-component molecular clusters are investigated by molecular dynamics simulations, validated against XPS data. Finally, the radial structure of a two-component molecular cluster is investigated by XPS. Liquids have been studied for centuries, but still many questions remain regarding the microscopic properties. With the recent development of the liquid microjet technique, new insight into the atomic structure can be obtained. In this thesis we study aqueous solutions using photoelectron and Auger electron spectroscopy (AES). We investigate the structure of surface active molecules by XPS, study the Auger decay after core-level ionization in aqueous potassium chloride (KCl), and follow the changes in molecular structure of glycine as a function of pH.

The present paper aims at a treatment technique designed for special industrial wastewaters contaminated with only traces of halogenated organic compounds (HOCs) - concentrations which are nevertheless large enough to make a discharge into municipal sewage works impossible. Our research follows the idea to detoxify the water by a selective destruction of the HOCs by hydrodehalogenation (HDH) reactions on palladium-containing nano-catalysts. Detoxification means that persistent HOCs are converted into organic compounds which can easily be removed by biodegradation in a wastewater treatment plant. A novel promising trend in environmental research is the application of nano-reagents (such as zero-valent iron) and nano-catalysts. As known from nano-sized metal particles, nanocatalysts have the advantage of very high reaction rates due to high specific surface areas and low mass-transfer restrictions. For special applications in wastewater treatment we were able to generate extremely active palladium catalysts on the basis of ferromagnetic carrier colloids. The magnetic nano-sized carriers (such as zero-valent iron or magnetite) were spiked with traces of Pd (0.1 wt.-%). These nano-catalysts have been successfully tested in different reactor systems at the laboratory scale. Using Pd on nano-scale supports leads to enormous activity of the catalyst which is several orders of magnitude higher than reached in conventional fixed-bed reactors. The ferromagnetism of the carriers enables a separation of the catalysts from the treated water by means of magneto-separation. This gives the chance to reuse the catalyst several times. The preferred reductant for the HDH reaction is molecular hydrogen. For highly contaminated waters, alternative hydrogen donors such as formic acid have been successfully tested.

The electronic and geometrical structure of free neutral clusters and liquids have been studied using synchrotron-radiation based photoelectron and Auger electron spectroscopy in combination with lineshape modeling. A novel experimental setup has been developed for studies of liquids, based on the liquid microjet technique. Theoretical lineshapes have been computed using both classical (molecular dynamics) and quantum mechanical (mainly density functional theory) methods. Clusters are finite ensembles of atoms or molecules, ranging in size from a few to several thousand atoms. Apart from being fundamentally interesting, clusters are also promising as building blocks for nano-technology. In this thesis results are presented for rare-gas and molecular clusters, ranging from weakly van-deer-Waals bonded to hydrogen bonded. It is shown that the combination of core-level photoelectron spectroscopy (XPS) and lineshape modeling can be used to estimate the sizes of clusters. A model for treating the effect of inter-molecular nuclear relaxation upon ionization is proposed. The structure of single-component molecular clusters are investigated by molecular dynamics simulations, validated against XPS data. Finally, the radial structure of a two-component molecular cluster is investigated by XPS. Liquids have been studied for centuries, but still many questions remain regarding the microscopic properties. With the recent development of the liquid microjet technique, new insight into the atomic structure can be obtained. In this thesis we study aqueous solutions using photoelectron and Auger electron spectroscopy (AES). We investigate the structure of surface active molecules by XPS, study the Auger decay after core-level ionization in aqueous potassium chloride (KCl), and follow the changes in molecular structure of glycine as a function of pH.

Performance and reliability of dynamic physical contacts between two solid surfaces has challenged technologists from pre-Hellenistic pulleys and Da Vinci mechanisms for transmission of mechanical energy to modern switches and relays for transmission of electrical energy, currently a $4B global industry that impacts telecom and mobile phones, automotive, aerospace and consumer products. Local oscillations in the stress, temperature and electrostatic potential during a contact cycle result in the evolution of the topology, chemistry and physical properties of the two surfaces, degrading the characteristics of the junction with service. These challenges are especially acute in ultra-fast (MHz) micro electromechanical system (MEMS) relays requiring high current, low impendence operation over billions of cycles. Various surface modification approaches, such as gold alloys and refractory coatings and self-assembled monolayers, have been unsuccessful in enabling the maintenance of these multifunctional (low adhesion, low resistivity) contracts. Taking inspiration from 1940s mercury-wetted electrical contact relays and current nanoparticle organic solutions, here we demonstrate that nobel metal nanoparticle liquids (NPLs) provide reconfigurable and replenishable surface asperities that extend the durability by 10 to 100 times without the inherent toxicity of mercury or capillarity that limits relay miniaturization. These non-volatile NPLs are made of 5-20 nm Au and Pt nanoparticles with organic coronas consisting of surface tethered ionic liquids. The nanoscopic size and corona fluidity are critical in providing sufficient electrical conductivity through nanoparticle jamming while maintaining a low contact adhesion by dynamically restoring a nanoscopic asperity texture via liquid surface migration., Submitted for publication in the journal, Nature. Prepared in collaboration with University of Dayton Research Institute; Southwestern Ohio Council for Higher Education (SOCHE); and Micheline American Research and Development Corporation. The original document contains color images. All DTIC reproductions will be in black and white.

In this Thesis experimental studies of nano-clusters using synchrotron radiation based photoelectron (UPS and XPS) and Auger Electron Spectroscopy (AES) are presented. The investigations may be divided into two parts where the first reports on the structure of heterogeneous two component clusters, and the second concerns electronic decay processes. Using photoelectron spectroscopies as investigative tools the radial composition of heteroclusters of argon mixed with xenon, krypton or neon has been determined. Two methods of heterogeneous cluster production were employed: co-expansion and doping/pick-up. By analyzing the line shapes, energy positions, and widths of the spectral cluster features the radial composition of the clusters produced by co-expansion were found to form close-to-equilibrium structures, placing the component with larger cohesive energy in the cluster core while the second component was to varying degree segregated toward the surface. By instead using the doping/pick-up technique the opposite radial structures, i.e. far-from-equilibrium structures, may be formed. In the case of argon/krypton clusters a similar surface structure is formed regardless of production technique. The second part of the Thesis concerns post-ionization decay processes. Experimental evidence for the Interatomic Coulombic Decay process, a theoretically predicted decay channel, is presented in a study of homogeneous neon clusters. The time scale of the decay was determined to 6±1 fs for bulk atoms and >30 fs for surface atoms in the neon cluster, showing the connection between local geometry and dynamics of the decay. Another channel for electronic relaxation is Auger decay. This Thesis presents a method of disentangling the spectral surface and bulk responses from clusters in Auger spectra. Studies of argon clusters show that the AES technique is more surface sensitive than XPS, even at the same electron kinetic energy. Furthermore, the effect scattering of the photoelect

In this Thesis experimental studies of nano-clusters using synchrotron radiation based photoelectron (UPS and XPS) and Auger Electron Spectroscopy (AES) are presented. The investigations may be divided into two parts where the first reports on the structure of heterogeneous two component clusters, and the second concerns electronic decay processes. Using photoelectron spectroscopies as investigative tools the radial composition of heteroclusters of argon mixed with xenon, krypton or neon has been determined. Two methods of heterogeneous cluster production were employed: co-expansion and doping/pick-up. By analyzing the line shapes, energy positions, and widths of the spectral cluster features the radial composition of the clusters produced by co-expansion were found to form close-to-equilibrium structures, placing the component with larger cohesive energy in the cluster core while the second component was to varying degree segregated toward the surface. By instead using the doping/pick-up technique the opposite radial structures, i.e. far-from-equilibrium structures, may be formed. In the case of argon/krypton clusters a similar surface structure is formed regardless of production technique. The second part of the Thesis concerns post-ionization decay processes. Experimental evidence for the Interatomic Coulombic Decay process, a theoretically predicted decay channel, is presented in a study of homogeneous neon clusters. The time scale of the decay was determined to 6±1 fs for bulk atoms and >30 fs for surface atoms in the neon cluster, showing the connection between local geometry and dynamics of the decay. Another channel for electronic relaxation is Auger decay. This Thesis presents a method of disentangling the spectral surface and bulk responses from clusters in Auger spectra. Studies of argon clusters show that the AES technique is more surface sensitive than XPS, even at the same electron kinetic energy. Furthermore, the effect scattering of the photoelect