8^th International Conference and Exhibition on Materials Science and Engineering May 29-31, 2017 Osaka, Japan

Biography:

Abstract:

This work uses molecular dynamics simulations to study surface and interface properties of PdHx that are relevant to hydrogen storage applications. In particular, surface energies, interfacial energies, surface diffusivities, and surface segregations are all determined as a function of composition and temperature. During the course of the calculations, we demonstrated robust molecular dynamics methods that can result in highly converged finite temperature properties. Challenging examples include accurate calculations of hydrogen surface diffusivities that account for all possible atomic jump mechanisms, and constructions of surface segregation composition profiles that have negligible statistical errors. Our robust calculations reveal that the Arrhenius plots of hydrogen surface diffusion is ideally linear at low compositions, and becomes nonlinear at high compositions. The fundamental cause for this behaviour has been identified. This nonlinear surface diffusion behaviour is also in good agreement with available experimental data for bulk diffusion. The implication of our calculated properties on hydrogen storage application is discussed.

Biography:

Jana Zarubova gained her Ph.D. in Biochemistry from the Charles University in Prague. Her research focuses mainly on the design and biological evaluation of materials for vascular and bone tissue engineering. Jana Zarubova participates in the development of bioreactors for dynamic cell culture. She has long-term experience with mesenchymal stem cell culture, differentiation and their co-culture with different cell types. Jana Zarubova is also interested in the extracellular matrix and its influence on cell behavior.

Abstract:

Cardiovascular diseases are one of the leading causes of death worldwide [1]. A common treatment option to replace the diseased blood vessels is vascular grafting using patient’s own blood vessels. The availability of such grafts is however limited by the patient’s age or pathology. Artificial alternatives to the autologous grafts are currently made of relatively inert non-degradable materials such as expanded polytetrafluoroethylene and polyethylene terephthalate [2]. These polymers have been successfully used for the replacements of blood vessels with a high blood flow and an internal diameter larger than 6 mm. However, smaller-diameter grafts show very poor long-term patency, largely due to the thrombogenicity of the artificial surface under low flow conditions and intimal hyperplasia [3, 4]. Recently, decellularized tissues have emerged as promising scaffolds for constructing replacements of various tissues and organs. In this study, decellularization of porcine vessels in a perfusion dynamic system was examined and compared with the manual decellularization procedure. The composition of extracellular matrix proteins [5], structure and mechanical properties of decellularized vessels were tested and compared with native blood vessels. Decellularized scaffolds were then seeded with endothelial cells and adipose-derived stem cells and cultured in a bioreactor with defined shear stress in order to simulate physiological conditions in the body.  It was shown that dynamic decellularization dramatically shortens the time needed for decellularization. It also enables standardization of the decellularization process resulting in a consistent scaffold material. Cultivation of recellularized vessels under dynamic conditions induces anti-thrombogenic phenotype in endothelial cells and improves cell adhesion and ingrowth into the scaffold. 

Biography:

Ms. Yi Wen Phuan received her B.Eng (Hons 1A) in Chemical Engineering from Monash University Malaysia in 2013. She continued her postgraduate studies in 2013 under the supervision of Assoc. Prof. Dr. Meng Nan Chong and Assoc. Prof. Dr. Eng Seng Chan. Her research focuses on the electrochemical synthesis and modification of nanostructured hematite (α-Fe₂O₃) as an efficient semiconductor photoanode material for application in photoelectrochemical (PEC) water splitting.

Abstract:

In this study, a novel ternary hematite (α-Fe₂O₃)-based nanostructured photoanode with excellent photoelectrochemical (PEC) performance consisting of 2D-electrochemical reduced graphene oxide (eRGO) and nickel oxide (NiO) was successfully developed through electrodeposition method. The surface morphology and structural properties of the nanostructured photoanode were characterised by using field emission-scanning electron microscopy (FE-SEM), and high-resolution transmission electron microscopy (HRTEM). Results showed that the flexible eRGO sheets provide intimate and coherent interfaces between α-Fe₂O₃, NiO and eRGO, promoting charge transfer over their interfaces and thus, lowering the photogenerated electron-hole pairs recombination rate. X-ray diffraction (XRD) patterns, Raman spectra and X-ray photoelectron (XPS) spectra validated that both eRGO and NiO were successfully electrodeposited onto the ternary eRGO/NiO/α-Fe₂O₃ nanostructured photoanode. As evidenced from the ultraviolet-visible (UV-vis) diffuse reflectance spectra, the incorporation of eRGO and NiO has endowed α-Fe₂O₃ nanostructured photoanode with a wider spectral absorption range where the light absorption intensities in the visible light and near infared regions are improved. Electrochemical impedance spectroscopy (EIS) further confirmed that the ternary eRGO/NiO/α-Fe₂O₃ nanostructured photoanode possesses the lowest charge transfer resistance, indicating that the combined effects of eRGO and NiO could improve the electron mobility by impeding the recombination process of photogenerated charge carriers and resulting in superior PEC performance. This is because eRGO sheets act as surface passivation layer and electron transporting bridge that increase the electron transfer at the semiconductor/liquid junction. Whereas, NiO serves as hole acceptor that effectively hinders the recombination of photogenerated electron-hole pairs and accelerate the interfacial charge transfer. The solar hydrogen evolution rate of the ternary eRGO/NiO/α-Fe₂O₃ nanostructured photoanode was about 3-fold higher than the bare hematite. It is expected that the fundamental understanding gained through this study is helpful for the rational design and construction of highly efficient ternary nanostructured photoanodes for application in solar hydrogen energy conversion through PEC process.

Biography:

Mr. Chot Chun Yuan graduated with a Bachelor of Engineering in Chemical Engineering with Honours from UCSI University in 2015. He joined Monash University Malaysia in the same year for postgraduate studies under the supervision of Assoc. Prof. Dr. Meng Nan Chong, Prof. Dr. Ai Kah Soh, and Assoc. Prof. Dr. Khang Wei Tan. His research focuses on the development of molybdenum trioxide-based photoanodes with charge storage capacity for PEC water splitting under illuminated and non-illuminated conditions. 

Abstract:

Photoelectrochemical (PEC) technology is one of the most promising methods that converts solar irradiation into storable chemical energy in the form of hydrogen (H₂) via water splitting reaction. To date, the PEC technology has been studied extensively in terms of the synthesis of photoelectrodes such as synthesis approaches, structural modifications, and improvement of photoresponses. However, the PEC technology is still limited by one of the most challenging bottlenecks where all PEC cells can only be operated under well-illuminated condition. Generally, light source is the most crucial element in a PEC cell as it initiates the photoreactions and producing photogenerated charge carriers. When the light source used is withdrawn (i.e. non-illuminated condition), all the photoreactions will be terminated instantaneously. Therefore, there is a growing significance in enabling the operation of PEC technology under non-illuminated condition via the rational design of photoelectrodes for efficient solar energy conversion and storage. Recently, molybdenum trioxide (MoO₃) has attracted numerous research attention due to its unique layered crystalline structure that leads to charge storage capacity in PEC technology application. Within the MoO₃ structure, a portion of the charges could be stored in the layered crystalline structure via intercalation (MoO₃ + xNa⁺ + xe^- à Na_xMoO₃) during the well-illuminated condition. Whilst the stored charges will be released from the molybdenum bronze (Na_xMoO₃) and continuously flow to the counter electrode via de-intercalation (Na_xMoO₃ à MoO₃ + xe^- + xNa⁺) during non-illuminated condition. Thus, the main aim of this work was to synthesize thin films of MoO₃ via the aerosol-assisted chemical vapour deposition (AA-CVD) method for application as photoanode used in PEC water splitting. This was followed by a systematic optimisation of the ultrasonication time on the precursor colloidal suspension, and annealing temperature on the eventual crystalline MoO₃ structure formed. FE-SEM images showed that the MoO₃ thin films that are synthesized from the AA-CVD method exhibited a 3D plate-like crystalline structure. Further electrochemical characterisations measured that the AA-CVD synthesized MoO₃ thin films possessed a high charge storage capacity of 1.22 mC/cm² and a low charge transfer resistance of 87.6 Ω at the optimum ultrasonication time of 25 min and annealing temperature of 550^o. 

Biography:

Mr. Yaw Chong Siang graduated with a Bachelor of Engineering in the discipline of Chemical Engineering with Honours from Monash University Malaysia in 2014. He returned to Monash University Malaysia the following year for postgraduate studies under the supervision of Assoc. Prof. Dr. Meng Nan Chong and Prof. Dr. Ai Kah Soh. His research focuses on the synthesis of BiVO₄-based heterojunction-tandem photoelectrodes for solar hydrogen energy conversion from PEC water splitting.

Abstract:

Hydrogen (H₂) has featured prominently as a potential alternative and renewable energy source. To date, one of the most feasible production routes of solar H2 generation is through the photoelectrochemical (PEC) water splitting. In this regard, bismuth vanadate (BiVO₄) is a promising semiconductor photoelectrode material that can be used for PEC water splitting. This is owing to its low-cost, relatively narrow bandgap of 2.4 eV and favourable positioning of valance band edge that provides sufficient overpotential for water oxidation. To date, however, the practical photocurrent yield of BiVO₄ photoelectrode reported in the literature is far lower than its full potential due to poor photogenerated carriers separation and high bulk and surface recombination rates. The emergence of heterojunction photoelectrode design is considered to be able to address these setbacks, while providing an internal electric field for improving the photogenerated charge carriers transfer in a PEC cell setup. Thus, the main aim of this study was to fabricate a heterojunction V₂O₅/BiVO₄ photoanode due to the fact that V₂O₅ is the most stable form of vanadium oxide, and has received intense interest due to its inherently good electrochemical and photochemical properties. The resultant heterojunction V₂O₅/BiVO₄ photoanode structure was characterised by using field emission-scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), UV-visible spectroscopy, and a number of PEC measurements and analysis. Through this study, it was found that the photocurrent density of a bare BiVO₄ photoanode increased from 0.07 to 0.40 mA/cm² (at 1V vs. Ag/AgCl) after the formation of a heterojunction photoanode structure with an underneath V₂O₅ layer. This is almost a 6-fold improvement in terms of photocurrent density, and this study has demonstrated the presence and role of V₂O₅ in the heterojunction structure that extends the light absorption range as well as improving the electrons mobility and effective separation of photogenerated charge carriers. 

Biography:

My current position is a Scientist and Researcher at Department of Applied Radiation and Isotopes Faculty of Science, Kasetsart University. I have 4 years experience in radiation detection and nuclear instrument operation i.e. Gamma spectrometer, Liquid scintillation counter and Imaging plate system. Also, I have experiences in the design and development of radiation instrument such as development of data storage system for multichannel analyzer by using SD card. I am also responsible for the academic services in radionuclide measurement in foods imported from Japan.

Abstract:

Graphene aerogels (GAs) is one of the most promising nano materials leading to several potential applications to capture and sequestration of radionuclides, in this work, the synthesis graphene oxide (GO) was fabricated based on the modified Hummer’s method. Graphene oxide gel (GO gel) prepared by centrifuged graphene solution at 5000 rpm for 20 min then it washed by DI water. In case of graphene aerogel, the dry graphene oxide gel by Freeze Drying (at -10 °C for 300 min). For absorption part we mixed GO gel 0.5 g and GAs 0.5 g with Sodium iodide solution concentration 3.40% (w/v) at room temperature for 24 hours. It was revealed that the type of graphene has impacts to the adsorption iodine particles in water. The results of scanning electron microscopy (SEM) showed iodine particles on the surface of GO aerogel more than GO gel. Moreover the results of EDX show percentage of Iodine element inside The GO aerogel have 14.97% it better than the GO gel have 4.82 % of iodine element on the surface. 

Biography:

Professor Chong is an Associate Professor at Monash University Malaysia. He is also holding several adjunct positions and a prestigious fellowship, including a Visiting Professor at the University of Ulsan, Republic of Korea; a Senior Research Fellow at the University of South Australia; a Visiting Scientist at the Max Planck Institute for Chemical Energy Conversion, Germany; and being awarded the prestigious Royal Society Newton Advanced Fellowship (UK) in collaboration with University College London. To date, he has published close to 130 publications in journals, conference proceedings, book and book chapters, and technical reports. 

Abstract:

Solar energy being the largest renewable energy source on earth is an attractive energy source option that could be harnessed to electrify the cities of future. Among the various available solar-based technologies, the conversion of solar into storable form of hydrogen (H₂) energy via the photoelectrochemical (PEC) technology is a promising way to harness the great benefits from the Sun. This is achieved through the application of nanostructured semiconductor photoelectrodes in an electrochemical cell, whereby water molecules are dissociated into H₂ and oxygen through the sequential PEC reactions occurring on the semiconductor surfaces. To date, however, almost all the singular semiconductor photoelectrodes used exhibited poor performance and low efficiency during the solar H₂ fuel conversion. The effective separation of photogenerated charge carriers in photoelectrodes is a key to alleviate this technical issue. This presentation outlines the photogenerated charge transfer properties and PEC water splitting ability in various nanostructured semiconductor thin films and composites. Specifically, singular and composite semiconductor materials of α-Fe₂O₃, BiVO₄, and MoO₃ synthesized on fluorine-doped tin oxide as active photoelectrodes used for solar energy conversion and storage are discussed. Additionally, the role and mechanism of metal and non-metal dopants on the photogenerated charge transfer properties of semiconductor thin films and composites are elucidated. These are further interpreted using the outcomes from an advanced suite of characterisation methods, including FE-SEM, EDX, XPS, XRD and FTIR, and EIS. It is believed that the fundamental understanding gained through our studies is essential and helpful to design high-performance photoelectrodes for the application in PEC water splitting. 

Biography:

Montadhar Almoussawi is a PhD student working on a project about friction stir welding of steel alloys, he is doing modelling and simulation for the process, tool optimisation and many experimental including SEM_EDS, XRD residual stress analysis and heat treatments. The project aim is to control the welding parameters in order to produce sound welds.

Abstract:

The recants findings in unpublished work on friction stir welding of DH36 steel carried out at TWI company shows elements segregation of Mn, Si, O, Al when the welding speeds exceeds 500RPM-400 mm/min. The mechanism of this segregation is not fully understood and the presence of Oxygen within this segregated elements is also needs investigation. This work investigate for the first time the elements segregation of DH36 steel by carrying out many heat treatments in within ranges of temperatures 1200-1500 and different cooling rates. Two welding speeds were also used during the welding process, low welding speeds (100mm/min, 200RPM) and high welding speeds (400mm/min, 550RPM).  The results showed that segregation is only starting when the temperature exceeds 1400 and the complete segregation of Mn, Si, O, Al is occur at 1450C and also is associated with acicular ferrite formation. It is found also high rotational speeds exceeds 500RPM are causing a local melting at advancing-trailing side. The study is aim to estimate peaks temperatures limits that is not causing segregation by choosing the suitable tool rotational and traverse speeds.

Biography:

June Park earned his Ph. D in Physics at Chung-Ang University, South Korea, in Feb. 2011. He had studied optical properties of nanomaterials including carbon nanotubes, graphene and carbon related materials in his thesis. He worked as a PostDoc. with experience in synthesizing 2 dimensional materials for use in sensor, optical fiber laser and electronic devices using CVD mainly. Now, he is working for optical lens system at Korea Photonics Technology Institute. 

Abstract:

Chalcogenide glasses including chalcogen elements sulfur, selenium and tellurium, have been studied in optics system for their unique properties including high refractive index and non-linearlity [1]. Among various chalcogenide glasses, Ge-Sb-Se glasses show a good transmittance in the NIR and midIR spectrum from 2 µm ~ 16 µm and have excellent moldability for making molded lens. In order to find optimal lens molding conditions, we investigated thermal properties of Ge-Sb-Se glasses by varying different composition ratio. All of glass samples were synthesized by using melt-quenching method in rocking furnace. The samples are categorized with two kind of chemical formula; Ge_(30-x)Sb_(10+x)Se₆₀ and Ge_(32.5-x)Sb₁₀Se_(57.5+x). To confirm amorphous phase of samples, X-ray diffraction measurement was performed. The thermal and thermomechanical properties of Ge-Sb-Se glass sample were investigated using differential scanning calorimetry (DSC) and thermo mechanical analyzer (TMA), respectively. According to increase of Ge element, mean coordination number (MCN) is increased as shown in Fig. 1. And, we found that the glass transition temperature (T_g) of Ge_(30-x)Sb_(10+x)Se₆₀ decreased as the increase of MCN of Ge_(30-x)Sb_(10+x)Se₆₀. It is concluded that the thermal behavior of Ge-Sb-Se glass system is related to the mean bond energies of the elements. Finally, we optimized molding condition of chalcogenide glass system with their thermal properties.

Biography:

Dusadee Khamboonrueang is a PhD student in Physics, Department of Physics. Faculty of Science Kasetsart University, Bankok  and a lecturer in major Physics, Department of Science, Faculty of Science and Technology Nakhon Sawan Rajabhat University, Nakhon Sawan, Thailand. Her research interest is the research on how to synthesize the composite of titanium dioxide – grapheme, the properties of composite and it’s applications. She has expertise in materials science and renewable energy.

Abstract:

Titanium dioxide – reduce graphene oxide (TiO2-RGO) composite having difference weight ratio up to 20 wt% were synthesis by hydrothermal method. The hydrothermal method were easier way to prepare TiO2-RGO composites and can also change graphene oxide to reduced graphene oxide along with the particles of titanium dioxide loaded on the surface of the reduce graphene oxide sheet. The image of scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) show the image of titanium dioxide particle dispersed on the surface area of reduce graphene oxide sheet. The peak from Fourier-transform infrared spectra analyzer (FT-IR) showed the peak of functional group of Ti-C-O at 1200 cm-1and1070 cm-1. XRD spectra show titanium dioxide anatase phase peak and The Magnetic properties of the TiO2-RGO were present in weight ratio 5 to 20 wt% as measured by SQUID magnetometer increased 25.14x10-4 emu/g.

Biography:

Dr. Erb received his Ph.D. (1980) in Materials Science from the University of the Saarland (Germany). He currently is a Professor in Materials Science and Engineering at the University of Toronto. He is named as inventor on 18 patents related to the synthesis of nanostructured materials by electrochemical methods, and has authored about 250 scientific publications in the field of nanomaterials. Professor Erb and his research team were the first to synthesize fully dense nanostructured materials in 1985, and developed numerous industrial applications for these materials with various companies. More recently, Professor Erb’s research has been broadened to include bio-inspired nanostructures. 

Abstract:

One specific type of corneal nano-nipple arrays found on many insect compound eyes are hexagonally arranged protrusions in the shape of inverted paraboloids. Prior studies have focused on the anti-reflection properties of the eyes due to the nano-nipple structure [e.g. 1], which depends mainly on the shape of individual nipples. However, in the past little attention was given to the details of the arrangement of nano-nipples, which was qualitatively described as consisting of multiple domains. In the current study, remarkable defect structures were found through structural analysis using crystallographic principles.

The investigated species is the Mourning Cloak butterfly (Nymphalis antiopa), which is common in North America as well as Europe and Asia. On its corneas, nano-nipples are predominantly in 2-D hexagonal arrangement with an average diameter of 170 nm and an average lattice parameter of 205 nm [2]. An eye with 2 mm in diameter has approximately 10,000 ommatidia and 140 million nipples. However, within the hexagonal structure, there are nipples that deviate from the regular arrangement by having different numbers of nearest neighbours (NN); instead of 6 NN required by hexagonal symmetry, about 10% of nano-nipples have 5 or 7 NN and are described as 5- and 7-fold coordination defects (disclinations), respectively. Since the 5- and 7-fold disclinations usually occur adjacent to each other, they are collectively referred to as 5-7 defects.

Biography:

Dr. Sirikanjana Thongmee now is an Assistant professor of Physics, She was in Physics Department Faculty of Science, Kasetsart University. She got her B.Sc in Physics at Prince of Songkla University, M. Sc. in Chemical Physics at Mahidol University and Ph.D. (Materials Science) at National University of Singapore. Dr. Sirikanjana Thongmee got the Thesis Presentation Award, Mahidol University, Thailand, 1999 and Outstanding Research of the Year 2^nd Class Award, Office of the National Research Council of Thailand, Thailand, 2003. Currently Dr. Sirikanjana Thongmee’s researches focus on the metal doped ZnO for spintronics and gas sensors applications, magnetic nanomaterials, graphene oxide for different applications and activated carbon from agricultural waste

Abstract:

The effects of substituting Ag³⁺ into Ag-doped ZnO NR’s, Zn_1-xAg_xO (x =0.0, 0.1, 0.2, 0.3, 0.4 and 0.5) are investigated. X-Ray Diffraction (XRD) patterns do not indicate that the Ag ions are systematically replacing the Zn ions but instead are forming into nano Ag particles. Since the radius of the Ag³⁺ ions (0.126 nm) is much greater than that of Zn²⁺ (0.072 nm), there would be a tremendous amount of lattice distortion if at the higher level of Ag doping if the Ag ions replaced the Zn ions at the lattice sites.  In the XRD patterns for the pure and x = 0.1 NR’s, we did not observe any peaks of the fcc crystal structure of Ag. When Ag was increased to x  ³ 0.3, we see the reflection from the Ag (1 1 1) and Ag (2 0 0) planes. SEM shows the morphologies of NR’s are changing along with the shape of the rods as the level of Ag substitute increase. For pure ZnO, the rods are orientated perpendicular to the plane appear to be hexagonal. The SEM images of the 1% Ag doped ZnO NR’s still show the presence of rod shaped particles. The morphologies of the 2% Ag doped ZnO NR’s are quite different. Some of them appear to star shape with a few arms emanating from a central point.  SEM image of 5% Ag doped NR’s showed ZnO NR’s appear to be “broccoli” shaped. 

The results from PL spectrum revealed that the visible light emission of the undoped ZnO NR’s are somewhat suppressed but becomes strongly enhanced (in the region between 450 – 600 nm) as the level of Ag doping is increased to 1%, then to 2%.  This could be taken as evidence that more defects were being created as the Ag ions were replacing the Zn in their sites in the wurtzite structure.

Biography:

Dr Jun Ding is Professor at Department of Materials Science & Engineering, National University of Singapore. He has been working on functional materials (particularly magnetic materials) over 25 years. His current research is focusing on additive manufacturing (3D printing) with the emphasis of advanced functional and multi-functional devices.

Abstract:

Additive manufacturing has been widely used in fabrication of structural and functional devices.  Additive manufacturing has the great potential in producing novel products with geometry and functionality which cannot be or very difficultly obtained using conventional manufacturing techniques.  Polymeric materials have been widely used in additive manufacturing because of their low melting temperatures.  Some metals have been used in additive manufacturing after the successful development of novel technologies such as selective laser melting.  High-quality ceramic structures are still challenging because of high melting temperature and brittleness.  We have paid a great attention on additive manufacturing of ceramic structures.  In our recent research, we have used extrusion free-forming in fabrication of high-quality ceramic structures including YBCO high-Tc superconductor, hard and soft magnetic ferrites and ZrO₂.  In addition, digital light projection has been used in fabrication of ceramic structures.

Biography:

As the PhD researcher in Department of Chemistry, National Central University, Taiwan, Canggih Setya Budi focuses his research interests on fabrication of nanomaterials including mesoporous materials, metal nanoparticles, bimetallic alloyed nanoparticles, nano-composites and their utilization for the energy storages and catalytic reactions. His academic and research skill are well distinguished and enabling him to publish his research in good journal and achieve academic scholarship from Taiwan government. He is actively involved as the member of High Energy Battery and Nano-catalyst Research Group which enabling him to share the current issues and ideas among the researchers. For about one and half years, he also experienced to work in Research and Development (R&D) division at Pura Barutama Ltd. Co., as the largest paper and printing company in South-East Asia.

Abstract:

Superior catalysts for the catalytic reduction of 4-nitrophenol (4-NP) based on alloyed bimetallic system of Ag-Ni nanoparticles have been successfully fabricated by facile immobilizing technique within the cage-pores of carboxylic acid –COOH functionalized mesoporous silica SBA-16 (named Ag_xNi_1-x@S16C, where x is molar ratio), following procedure in our previous works with further modification.^1,2 It was greatly acknowledged that the –COOH functional groups on mesostructure silica support play a critical role in improving the interaction with target cation and confining the crystallite growth during calcination-reduction process.^3,4 Under wet impregnation in basic condition, the negatively charged density of S16C support (as confirmed by zeta potential measurement) endows effective sites to undergo ionic interaction with Ag(I)/Ni(II) cation. The successful functionalization of the organic functional group on the silica framework were well identified with detailed ¹³C cross polarization magic angle spinning nuclear magnetic resonance (CPMAS NMR), ²⁹Si MAS NMR, and Fourier transform infrared (FT-IR) spectroscopy.⁵ It worth noting that without stabilizing or reducing agents, the highly dispersed Ag-Ni nanoparticles immobilized in cage-pores of S16C could be achieved by calcination-reduction process under inert conditions. Further characterizations, alloying bimetallic of Ag-Ni nanoparticle has been confirmed by the powder X-ray diffraction, X-ray photoelectron spectroscopy, energy-dispersive X-ray analysis and high resolution transmission electron microscopy. Interestingly, the presence of Ni in bimetallic alloy system could decrease the size of Ag-Ni NPs up to sub-3 nm, much smaller than that of only Ag NPs. As the catalyst for the reduction of 4-NP, the Ag_0.4Ni_0.6@S16C and Ag_0.6Ni_0.4@S16C perform much higher catalytic activity over monometallic counterparts. This enhanced catalytic activity might be attributed to the size, loading amount, high specific surface area, well-dispersed and unique electronic properties arising from Ag-Ni bimetallic system supported in cage-type S16C. Furthermore, their magnetic properties allowing a facile and rapid recycle technique for reuse. 

Biography:

Amina is a PhD student working on developing new materials for use as electrolyte membrane in order to improve the electrical, mechanical and alkaline behavior toward. The concept is based on the generation of totally new polymers or copolymers offering a good compromise for industrial utilization. The final products are normally less expensive than the actual commercial ones and present pretty good compromises proving by different analysis and measurements.

Abstract:

Electrolyte membranes are very important component in fuel cells and influence significantly their performance. Polymers such as  poly(olefin)s, poly(styrene)s, poly(phenyleneoxide)s, poly(phenylene)s, and poly(aryleneether)s that have been studied for use as electrolyte membranes for fuel cells. In this work, a series of electrolyte membranes have been synthesized by copolymerization of polybenzimidazole, polystyrene and polyvinylimidazolium. Various ratios were studied in order to realize a good compromise between high conductivity, swelling ratio and water uptake. The conductivity test reveals that the percentage of each component in the copolymer influences directly the ion conductivity of the final membranes. The copolymerization of polystyrene and polyvinylimidazolium was confirmed by ¹H NMR and FTIR. Compared to the commercial reference fuel cell membrane, A201 Tokuyuama; 6 of the synthesized membranes exhibit better conductivity at high temperatures and 3 at all temperatures. The best conductivity is observed for membrane PBI_0.5 S₁VIB₅ which reaches chloride conductivity of 26.3 mScm^-1 at 25°C and 73.7 mScm^-1 at 100 °C; the membrane has an Ion Exchange Capacity of 2.6 mmol/g and a low activation energy of 6.62 kJ/mol; membrane PBI_0.5 S₂VIB₅ is one of the 3 membranes with a 10.77% swelling ratio with a 6.66 kJ/mol as activation energy. All synthesized membranes show a linear Arrhenius behavior and exhibit low activation energy and mostly an in plane swelling ratio. From TGA and DSC analyses, they membranes are thermostable up to 250 °C. Morphology studies explored via TEM and AFM show a well-developed bicontinuous phase distribution of hydrophilic and hydrophobic regions that confirms facile ion transport channels.  

Biography:

Ganesh Agawane obtained his PhD in 2015 from Chonnam National University, Gwangju, S. Korea. His PhD thesis title is Fabrication of CZTS thin film solar cells by sol-gel spin-coating and PLD method. Presently he is working as a post–doctoral researcher at Korea Photonics Technology Institute (KOPTI), Korea. His present research interest includes preparation of Er³⁺ doped Yb³⁺ sensitized fluorophosphate glasses for 1.53 um LiDAR applications.

Abstract:

Statement of the Problem: Erbium doped fiber amplifiers (EDFAs) have been studied extensively to convert the NIR radiation into the visible light. The EDFAs can be applied in numerous optical applications like; optical fiber communication, data storage, biomedical diagnostic, color display, sensor, eye-safe laser and undersea optical communication. The host glass matrix noticeably affects the emission properties of the rare earth ions and, therefore, a broad study is obligatory for the exploration of the paramount apt host matrix. Fluorophosphate (FP) provides an excellent way to obtain the best matrix for doping of rare earths. The FP matrixes endure fracture toughness effortlessly making stable solid state lasers over extensive physical qualities. These matrixes are perfect for large inhomogeneous augmentation, superior broadband and flatness due to low phonon energy. Methodology & Theoretical Orientation: In this study, we report preparation of Er³⁺/Yb³⁺ co-doped fluorophosphate (FP) glasses containing aluminium-metaphosphate by melt quenching technique. The UV-Vis-NIR absorption measurements were carried out and analyzed through Judd–Ofelt model. Various spectroscopic properties like radiative lifetime, transition probability, intensity parameters Ω_λ, emission cross-sections and stimulated absorption cross-sections at 1.53 μm have been evaluated. Findings: In this study, we report preparation of Er³⁺/Yb³⁺ co-doped fluorophosphate (FP) glasses containing aluminium-metaphosphate by melt quenching technique. The UV-Vis-NIR absorption measurements were carried out and analyzed through Judd–Ofelt model. Various spectroscopic properties like radiative lifetime, transition probability, intensity parameters Ω_λ, emission cross-sections and stimulated absorption cross-sections at 1.53 μm have been evaluated. The fluorescence lifetime was measured and calculated by non-exponential least square fit technique. The lifetime of the glasses first increased and then decreased with increased Yb³⁺ mol%. Conclusion & Significance: Near infrared absorption and absorption cross-section were increased with an increase in YbF₃ content. Emission elucidations showed that the glass matrix and concentration of Er³⁺ and Yb³⁺ ions significantly impact the emission characteristics and radiative lifetimes. The longest lifetime of 12 ms proved the better host matrix and 2 mol% YbF₃ is the best condition for Er co-doped glasses.

Biography:

Osvaldo Mitsuyuki Cintho has his expertise in high energy ball milling, cryogenic highenergy ball milling and cryogenic deformation processes. For analysis of these processes products, he developed devices and techniques like cryogenic x-ray diffraction system, cryogenic samples preparation methods for TEM-Transmission Electron Microscopy, Cryogenic system for the XTMS: x-ray diffraction and thermo mechanical system on Synchrotron line.  Currently, he is researching about mechanical behavior and characterization of  metals and steels on cryogenic conditions in order to propose a deformation mechanisms and recovering processes on this condition.

Abstract:

Deformation of metals at cryogenic temperatures (CT), or at temperatures close to liquid nitrogen (LN) temperature can suppress partly the dynamic recovery during deformation, allowing a higher final density of defects in the material than on a deformation at room temperature (RT). In another way, unusual deformation mechanisms can take place on cryogenic conditions. The dynamic recovery and recrystallization has a great dependence on stacking fault energy and on annealing characteristics due the dislocations distributions are a function of this energy.  Annealing uses part of the stored energy in the material to the formation of new grains with low density of defects. In the present work pure metals with different stacking fault energy; aluminum (high), copper (medium) and silver (low); were rolled on room and cryogenic temperature and the products evaluate by tensile tests and hardness measurements just after rolling and after aging on room temperature. The results right after rolling show no great difference on tensile test curves but after aging, a very greater recovering of silver than other evaluated metals was detected. As showed on figure, both the rolled silver at room temperature and cryogenic temperature exibihit a great recovering level. In other side, the cryogenic rolling on silver promotes a higher tensile resistance and higher elongation after aging than the silver rolled at room temperature. This phenomenon can be due the unrecoverable defects at room temperature generated by deformations mechanism, which occurs at very low temperature (twinning). 

Biography:

Osvaldo Mitsuyuki Cintho has his expertise in high energy ball milling, cryogenic highenergy ball milling and cryogenic deformation processes. For analysis of these processes products, he developed devices and techniques like cryogenic x-ray diffraction system, cryogenic samples preparation methods for TEM-Transmission Electron Microscopy, Cryogenic system for the XTMS: x-ray diffraction and thermo mechanical system on Synchrotron line.  Currently, he is researching about mechanical behavior and characterization of  metals and steels on cryogenic conditions in order to propose a deformation mechanisms and recovering processes on this condition.

Abstract:

Deformation of metals at cryogenic temperatures (CT), or at temperatures close to liquid nitrogen (LN) temperature can suppress partly the dynamic recovery during deformation, allowing a higher final density of defects in the material than on a deformation at room temperature (RT). In another way, unusual deformation mechanisms can take place on cryogenic conditions. The dynamic recovery and recrystallization has a great dependence on stacking fault energy and on annealing characteristics due the dislocations distributions are a function of this energy.  Annealing uses part of the stored energy in the material to the formation of new grains with low density of defects. In the present work pure metals with different stacking fault energy; aluminum (high), copper (medium) and silver (low); were rolled on room and cryogenic temperature and the products evaluate by tensile tests and hardness measurements just after rolling and after aging on room temperature. The results right after rolling show no great difference on tensile test curves but after aging, a very greater recovering of silver than other evaluated metals was detected. As showed on figure, both the rolled silver at room temperature and cryogenic temperature exibihit a great recovering level. In other side, the cryogenic rolling on silver promotes a higher tensile resistance and higher elongation after aging than the silver rolled at room temperature. This phenomenon can be due the unrecoverable defects at room temperature generated by deformations mechanism, which occurs at very low temperature (twinning). 

Biography:

Dr. Chia-Jyi Liu is currently a Distinguished Professor at National Changhua University of Education, Taiwan. He received B.Sc. from National Taiwan University in 1984. He received Ph. D. The Johns Hopkins University in 1991 under the supervision of Prof. Dwain O. Cowan who discovered the first organic metal TTF-TCNQ. He worked as a post-doctor at The Johns Hopkins University, Southern Illinois University at Carbondale (1991-1992), as a visiting scientist at Superconducting Research Laboratory, International Superconductivity Technology Center, Japan (1992-1994), as a research fellow at Victoria University of Wellington, New Zealand (1995-1996) and as a researcher at Industrial Research Limited, New Zealand (1996). His current interest is now developing novel materials for thermoelectrics.

Abstract:

Thermoelectric materials can be used to generate electricity from waste heat via the Seebeck effect. High-energy input is often required to fabricate thermoelectric materials. In this talk, we present  a green route to synthesize Ag₂Te-Ag nanocomposites with the reaction taking place in one pot at room temperature without any organic substance involved. Various amounts of silver in the Ag₂Te-Ag nanocomposite can be obtained depending on the reaction period of time. A possible mechanism is presented for the formaiton of Ag₂Te-Ag nanocomposite. A core-shell structure at the incipient stage of Ag₂Te growth can be observed. However, the reaction duriation has a significant effect on the electrical transport behavior of the nanocomposites due to presence of various amounts of Ag, which might be beneficial for enhancing the performance of thermoelectric composites.

We also present a rapid route for fabricating co-doped Co_1-x-yNi_xFe_ySb₃ using hydrothermal methods. Hydrothermal synthesis was carried out at 170^°C for a duration of 12 h, followed by evacuated-and-encapsulated heating at 580^°C for a short period of 5 h. The resulting samples are characterized using powder x-ray diffraction, density, electronic and thermal transport measurements. Due to the bipolar effects on thermopower are shifted to higher temperatures as compared with the nondoped CoSb₃, the power factor of Co_1-x-yNi_xFe_ySb₃ is significantly enhanced in the high temperature region due to significant enhancement of the electrical conductivity and absolute value of thermopower. The thermal conductivity of Co_0.76Ni_0.14Fe_0.10Sb₃ decreases with temperature down to 1.02 Wm^-1K^-1 at 600 K. As a result, the largest zT of 0.68 is attained for Co_0.76Ni_0.14Fe_0.10Sb₃ at 600 K. We also analyze the lattice thermal conductivity to gain insight into the contribution of various scattering processes that suppress the heat transfer through the phonons in Co_1-x-yNi_xFe_ySb₃.