Abstract book for the proceedings of the 2nd International conference on structural nano composites (NANOSTRUC 2014), 20-21 May 2014, Madrid, Spain.

The purpose of the 2nd International Conference on Structural Nano Composites (NANOSTRUC 2014) is to promote activities in various areas of materials and structures by providing a forum for exchange of ideas, presentation of technical achievements and discussion of future directions. NANOSTRUC brings together an international community of experts to discuss the state-of-the-art, new research results, perspectives of future developments, and innovative applications relevant to structural materials, engineering structures, nanocomposites, modelling and simulations, and their related application areas. We would like to acknowledge the hard work, professional skills and efficiency of the team which ensured the general organisation. The nanoparticles and nanocomposites have a wide range of applications in various fields such as medicine, textiles, cosmetics, agriculture, optics, food packaging, optoelectronic devices, semiconductor devices, aerospace, automotive, construction and catalysis. Advancements in the nanotechnology industry promise to offer improvements in capabilities across a spectrum of applications. This is of immense strategic importance to the high performance sector which has historically leveraged technological advances in materials

Application of hydroxyapatite granules in posterolateral intertransverse lumbar spinal fusion

In many clinical disciplines used of bone graft is unavoidable such as to replace bone loss due to trauma, to fill in bone defect after tumour excision, for reconstructive surgery or spinal fusion. Calcium phosphate based hydroxyapatite is widely used bone graft substitute due to its similarity with the mineral components of bone matrix. This study was conducted to evaluate bone formation effect of this biomaterial in posterolateral intertransverse lumbar fusion, a novel site for its application. Twelve adult New Zealand white rabbits underwent bilateral intertransverse lumbar spinal fusion at L5-L6 vertebrae. One site of the animals was implanted with hydroxyapatite granules (HA group) while the contralateral sides received autograft and served as the control (AUTO group). Bone formation was assessed at 6 and 16 weeks by undecalcified histology and scanning electron microscopy. New bone was formed on the surface of hydroxyapatite granules and continually formed even at 16 weeks. Close contact between new bone and hydroxyapatite granules was demonstrated by scanning electron microscopy

Nanogenerators in Korea

Fossil fuels leaded the 21st century industrial revolution but caused some critical problems such as exhaustion of resources and global warming. Also, current power plants require too much high cost and long time for establishment and facilities to provide electricity. Thus, developing new power production systems with environmental friendliness and low-cost is critical global needs. There are some emerging energy harvesting technologies such as thermoelectric, piezoelectric, and triboelectric nanogenerators, which have great advantages on eco-friendly low-cost materials, simple fabrication, and various operating sources. Since the introduction of various energy harvesting technologies, many novel designs and applications as power suppliers and physical sensors in the world have been demonstrated based on their unique advantages. In this Special Issue, we would like to address and share basic approaches, new designs, and industrial applications related to thermoelectric, piezoelectric, and triboelectric devices which are on-going in Korea. With this Special Issue, we aim to promote fundamental understanding and to find novel ways to achieve industrial product manufacturing for energy harvesters

Fungal Nanotechnology

Fungal Nanotechnologies (FN) 1 and 2 provide updated and comprehensive information that deals with the green and sustainable production of metal- and organic-based nanostructures by various fungal species. Additionally, intracellular and extracellular mechanisms will be investigated, as well as fungal nanotechnology applications in the biomedical, environmental, and agri-food sectors. FN is still in its infant stage; therefore, many studies should be focused on this area. Plants, animal and humans will benefit greatly from this, and efficient and ecologically friendly approaches should be created

Production of ion exchange membrane for hydrogen fuel cell

A thesis submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the degree of Doctor of Philosophy in Engineering. Johannesburg, 2017Among of the components of the fuel cell, the polymer electrolyte membrane is critical to the performance and life time of the cell. Over the years the mechanical properties of the membrane, water management have tended to limit its wide spread commercialization as an alternative source of the renewable energy for portable power units. Fuel cell continues to attract extensive research interest as potential source of renewable energy. This work focuses on the production of ionexchange membrane (IEM) for hydrogen fuel cell, using cheap and locally available starting materials. The polystyrene-butadiene rubber (SBR) of different styrene and butadiene compositions, have been explored for functionality in fuel cell application. The production process was conducted in three stages: the first stage involved hydrogenation process followed by sulfonation process. The second stage entailed the production of carbon nano-spheres for the blending in the hydrogenated sulfonated polystyrene-butadiene rubber. The blending was also done between hybrid nanoparticles and hydrogenated sulfonated polystyrenebutadiene rubber. The third stage was the casting in thin film of blended solutions employing the evaporative method and the use of casting tape machine technique. The thin film was later on characterized and tested in a single fuel cell stack. Controlled hydrogenation of SBR employing catalytic method was achieved with maximum degree of hydrogenation in the range of: 90 – 92% for SBR with 23.5% styrene content and for SBR 25% styrene content 76 – 80% for SBR with 40% styrene content and 82 – 92% for SBR with 52% styrene content. The optimum conditions of this process were obtained using the Design of Experiments. SBR was also hydrogenated using a photocatalytic method and the percentage of hydrogenation for all SBR compositions used was found in the range between 60 and 74%. The hydrogenation results using the catalyst were higher compared to those obtained with the photocatalytic method. Therefore they were used to develop the kinetic model for prediction of hydrogenation process. Langmuir – Hinshelwood models were reviewed in this project as they explain these heterogeneous catalytic processes. Data from the kinetic tests were fitted to Langmuir – Hinshelwood models and reaction constants were found in the range between 0.445 h-1 and 0.610 h-1 for the reaction temperature between 20 and 30°C. The hydrogenated SBR of different compositions were effectively sulfonated with chlorosulphonic acid employed as first sulfonating agent of concentrations 0.15, 0.175 and 0.25M for SBR 23.5 and 25% styrene content, for SBR 40% styrene content and for SBR 52% styrene content, respectively. The degree of sulfonation was found in the range between 56 and 72% depending on the rubber composition. Trimethylsilyl chlorosulfonate used as the second sulfonating agent was like wise attached to the same polymer back bone and the degree of sulfonation was between 59 and 74% depending on the rubber’s styrene content. Non-conductive carbon nanospheres (CNS) of uniform size of about 46 nm were produced employing the non-catalytic chemical vapour deposition method at 1000°C. Acetylene and argon were respectively used as carbon source and carrier gas, in a reactor of 16 mm in diameter. Successful blending of 4 wt% nanoparticles and hydrogenated sulfonated styrene butadiene solution was accomplished by magnetic stirring technique combined with ultrasonication at 60% amplitude. The blended solution was casted to produce a thin film membrane of 156 μm thickness. Further the tensile strength test of the membranes has shown an increase in Young’s Modulus by 72-120% for all the rubbers. This test was done using TA.XTplus, Texture Analyser machine. The water uptake increment was in the range of 20-27% and thermal stability in the range of 2-20% depending on the rubber composition. Purchased electrodes from FuelCellsEtc (USA), were pasted on both sides of the membranes by the means of hot press at 125oC for about 5 minutes at a pressure of 40 kPa. The Membrane Electrode Assembly (MEAs) fabricated were tested in the fuel cell stack. The highest power density of approximately 85mW/cm2 was obtained for 52% styrene nanocomposite membrane with 4% hybrid nanoparticles at the current density of 212.41mA/cm2 and the efficiency was between 41 and 43%. MEA fabricated with Nafion112 membrane was tested and yielded the open cell voltage of 0.79V, power density of about 77.34mW/cm2 and efficiency of 45%. Results obtained disclose that the MEA with nanocomposites based SBR 52% styrene composition yielded higher power density and higher voltage than the one with Nafion 112 which is one of the fuel cell membranes available on the market. The results obtained revealed that the nanocomposite membranes with 4% hybrid nanoparticles (CNS + SiO2) had higher voltage than the one with 4% CNS. These optimum conditions obtained in this work may be adopted for a typical continuous production of the membrane for hydrogen fuel cell.MT201

Accident Tolerant Fuels Claddings and the Evolution of their Surface Characteristics under Critical Heat Flux

Enhanced Accident Tolerant Fuels (ATFs) systems for light water reactors require higher temperature oxidation resistance in steam environments than the current UO2 – zirconium fuel system. Investigating the ATF materials’ surface properties is needed as they have evidenced to affect the Critical Heat Flux (CHF), which is an important parameter of the thermal-hydraulic performance required to provide safety margins. In this dissertation, the surface properties of FeCrAl alloys (APMT and C26M), Zircaloy-2, Zircaloy-4, and Cr-coating on Zircaloy-4 substrates produced by Physical Vapor Deposition (PVD) and Cold Spray (CS) were investigated according to their chemistry, topography, and wettability. The static contact angle changed from 75º for as-received Zircaloy-4 substrates to almost 20º after the Cr coating deposition. However, a hydrophobic recovery was noticed with environmental surface aging, which was explained by correlating the surface chemistry with surface energy. The surface chemistry of the coated samples and both FeCrAl alloys after CHF was studied thoroughly to understand their evolution at the early stage when subjected to CHF testing. The in-depth surface chemistry analysis evidenced the formation of various oxides that elucidate the rapid response of ATF cladding toward accident scenarios. The evolution of the materials’ surface chemistry also led to a noticeable increase in their wettability, with a slight increase in roughness. The investigation of the materials’ mechanical properties indicated an increase in hardness by 10-15% and an increase in their yield strength, as evidenced by the microindentation and ring compression tests conducted before and after CHF testing

Carbon nanotubes - Modification and application

Ph.DDOCTOR OF PHILOSOPH

Design of broadband antireflective layer stacks with low surface energy prepared by sol-gel method on glass for photovoltaic application

236 p.En el Capítulo 1 de este trabajo de investigación, se introducen los aspectos relevantes relativos la tecnología fotovoltaica, tales como los tipos de células solares, así como la forma en la que estas células se integran en el módulo, y algunos requerimientos de los materiales. A continuación, se introducen los materiales, tecnologías y rutas de síntesis más prometedoras que permiten depositar recubrimientos anti-reflectantes mecánicamente robustos, con propiedades combinadas de anti-ensuciamiento. Las técnicas experimentales, sus fundamentos físicos, y el equipamiento utilizado para el desarrollo del trabajo se describen en el Capítulo 2. En el Capítulo 3, se presenta el diseño óptico teórico del sistema de recubrimientos que permiten maximizar la transmitancia óptica, en el rango de longitudes de onda en los que determinados tipos de células solares son activas. A continuación, se presenta el método experimental de síntesis de los recubrimientos cuyas cualidades objetivo has sido obtenidas en el cálculo teórico. En el Capítulo 4 se han preparado recubrimientos ó funcionalizaciones para obtener superficies con baja energía libre superficial que potencialmente repelan el agua, contaminantes y polvo. En el Capítulo 5, los sistemas de recubrimiento más prometedores se han sometido a una batería más completa ensayos de fiabilidad, algunos de ellos utilizados por la industria fotovoltaica para validar los materiales y componentes utilizados en la fabricación de módulos fotovoltaicos. Este trabajo de investigación se concluye con un Capitulo 6 que contiene conclusiones generales, líneas futuras y producción científica

Design of broadband antireflective layer stacks with low surface energy prepared by sol-gel method on glass for photovoltaic application

236 p.En el Capítulo 1 de este trabajo de investigación, se introducen los aspectos relevantes relativos la tecnología fotovoltaica, tales como los tipos de células solares, así como la forma en la que estas células se integran en el módulo, y algunos requerimientos de los materiales. A continuación, se introducen los materiales, tecnologías y rutas de síntesis más prometedoras que permiten depositar recubrimientos anti-reflectantes mecánicamente robustos, con propiedades combinadas de anti-ensuciamiento. Las técnicas experimentales, sus fundamentos físicos, y el equipamiento utilizado para el desarrollo del trabajo se describen en el Capítulo 2. En el Capítulo 3, se presenta el diseño óptico teórico del sistema de recubrimientos que permiten maximizar la transmitancia óptica, en el rango de longitudes de onda en los que determinados tipos de células solares son activas. A continuación, se presenta el método experimental de síntesis de los recubrimientos cuyas cualidades objetivo has sido obtenidas en el cálculo teórico. En el Capítulo 4 se han preparado recubrimientos ó funcionalizaciones para obtener superficies con baja energía libre superficial que potencialmente repelan el agua, contaminantes y polvo. En el Capítulo 5, los sistemas de recubrimiento más prometedores se han sometido a una batería más completa ensayos de fiabilidad, algunos de ellos utilizados por la industria fotovoltaica para validar los materiales y componentes utilizados en la fabricación de módulos fotovoltaicos. Este trabajo de investigación se concluye con un Capitulo 6 que contiene conclusiones generales, líneas futuras y producción científica

Surface engineering : advanced protective coating and characterization of functionalised hydrophobic organic nanocoating

Abstract: Mitigation against corrosion and the improvement of other properties requires surface engineering. Many ways have been adopted to achieve this purpose, including processes, methods, and materials' compositional alteration. The chromium-based coating entails surface modification processes for diverse property enhancements, such as improved mechanical and electrochemical gains with stable microstructure and chemical evolutions, as well as thermal stability, but its carcinogenic nature has demanded alternative material that is green in nature; and therefore it is legislated to be phased out. Among the green materials developed, enhanced chemical and/or thermal properties have been achieved; while some demonstrated improved mechanical properties – without a combination of chemical or thermal stability. These have limited its deployments into applications. Hence, the quest for new and advanced solutions to have green or organic materials that can potentially replace chromium-based coatings is still on course – in an attempt to beat the new extended date of phase-out, particularly from the European Union Nations by 2024. ..D.Ing. (Mechanical Engineering