Biography:

Claude Delmas is a Research Director at French National Center for Scientific Research, France. He is a Solid State Chemist working in the field of positive electrode materials for secondary batteries. His expertise concerns layered oxides and phosphates able to intercalate reversibly sodium and lithium. During his career, he synthesized many new materials and he studied their structural and physical properties. He is an Author of more than 300 publications. He proposes a general classification of the layer oxides which is now used by all the scientific community working in this field.

Abstract:

Researches on battery materials has considerably increased during the last 30 years due to the huge development of lithium-ion batteries for portable devices and electric vehicles and more recently with the need to store energy in order to optimize its consumption. The chemical reactions occurring within the two electrodes are topochemical where the skeleton (2d or 3D) of the structure is preserved. The cell voltage is equal to the difference in fermi level between the two electrodes. If one electrode exhibits a constant voltage it can acts as reference and therefore, the cell voltage reflects all structure modifications which occurs on the material upon intercalation. The change is cell voltage depends on: The electronic band filling, the changes in the band structure due to change in composition, the modification of the Magdelung energy. In this schematic example, the monotonous decreases of the voltage during the intercalation reaction indicate that the reaction occurs through a monophasic domain. In numerous cases, the reaction mechanism is more complicated and involves biphasic domains and/or formation of materials with a specific composition. The voltage vs. composition curve is much more complicated and gives directly the phase diagram on the studied systems. For the solid state chemist the studies of the electrochemical reaction using a battery opens new possibility to determine phase diagram at RT, but also to synthesize new metastable phases from a precursor made by classical solid state chemistry. Exchange between alkali ions can be also considered in this frame. In this presentation, we report here about the NaxMO2 (M=3d elements) systems with a special focus on the phase diagram and the synthesis of new materials.

Recent Publications

1. Tournadre F, Croguennec L, Saadoune I, Carlier D, Y. Shao-Horn, Willmann P, Delmas C. On the mechanism of the P2-Na0.70CoO2 ® O2-LiCoO2 exchange reaction. J. Solid State Chem. 177 (8), 2790(2004)..
2. Berthelot R, Carlier D, Delmas C. Electrochemical investigation of the P2– NaxCoO2 phase diagram. Nature Materials, 10(1), 74 (2001).
3. Guignard M, Didier C, Darriet J, Bordet P, Elkaïm E, Delmas C. Vanadium Clustering/Declustering in P2-Na1/2VO2 Layered Oxide. Nature Mat 12, 74 (2013).
4. Guignard M, Carlier D, Didier C, Delmas C. On the mechanism of the P2- Na0.70CoO2 ® O2-LiCoO2 exchange reaction.Chem. Mat. 26(4)  1538 (2014).
5. Delmas C. Operating through Oxygen. Nature Chem., 8, 641 (2016).

Biography:

Arnaud Caron is a Material Scientist with expertise in “The multi-scale mechanical behavior of materials, surfaces and micro-components”. He has been an Assistant Professor at School of Energy, Materials and Chemical Engineering, KoreaTech, Republic of Korea since 2015. He completed his Engineering Degree in Materials Science in 2004 at University of Saarland, Germany. In 2009, he completed his Doctoral Degree in Materials Science at University of Saarland, Germany. From 2006 to 2015, he worked as a Research Associate at Institute of Micro- and Nano Materials, University of Ulm, Germany; WPI-Advanced Institute of Materials Research, Japan and; Leibniz-Institute for New Materials, Germany.

Abstract:

Understanding and controlling the surface mechanical behavior of materials is crucial for the development of new devices. We have investigated the sliding friction behaviors of different metallic couples with different enthalpy of mixing or reaction by friction force microscopy. In the low load regime, the friction between a single asperity, such as an AFM tip, and a metallic surface is governed by the formation of a junction and it’s shearing. Comparing the friction behavior of miscible and immiscible couples, we find that in the first case friction is governed by adhesion while the friction force is almost independent on the normal load. In the latter case of immiscible couples, adhesion is found to be low and the friction force linearly increases with the normal load. Statistical analysis of atomic stick-slip images recorded on an Au(111) surface with tips of different affinities with gold allows for a deeper understanding of our results. Expectedly, the periodicity of atomic stick-slip images corresponds to the interatomic distance of gold for immiscible counter-bodies. In contrast, for a reactive couple the periodicity of atomic stick-slip significantly differs from the gold interatomic distance and may correspond to structural length of an ordered phase at the tip-surface interface. These results provide new insights in the formation of interfacial alloys and their effects on metals friction. Furthermore, our findings shall serve as new guidelines for the selection of material couples for micromechanical devices involving sliding contacts.

Biography:

Mohamed Mokhtar is a Professor of Physical Chemistry at King Abdulaziz University (KAU). He was an Associate Professor at National Research Centre, Egypt, where he started his preliminary steps in the scientific research area. He is interested in advanced materials with special interest in their application in heterogeneous catalysis. In addition, he is Specialist in “Catalyst and adsorbent characterization with particular expertise in adsorption measurements”. He has published over 80 refereed publications and many international patents. He has numerous collaborative projects with public and private sector organizations.

Abstract:

Layered double hydroxides (LDHs) are class of two-dimensional (2D) anionic clays with brucite-like layered structure and intercalated anions. LDH materials can be converted to mixed metal oxides (MMO) nanocomposites after the thermal treatment. The MMO nanocomposites made from LDH precursors showed a uniform dispersion of metal ions as well as a high surface area in comparison to the metal oxides made by traditional chemical and physical method. Graphene oxide (GO) provides light-way, charge complementary, two-dimensional (2D) material that interacts effectively with 2D LDHs to form a hydride materials that improves the both the adsorption capacity of LDHs and their catalytic performance towards carbon-carbon coupling reaction. Recently, developing an efficient protocol for the synthesis of such materials was the interest of many researchers. Our group of research succeeded to synthesize a series of different LDHs /GO hybrids utilizing simple precipitation of LDH nanoparticles onto GO under controlled pH and temperature conditions. During the precipitation of positively charged LDH onto negatively charged GO, the mutual electrostatic interactions drive the self-assembly of hetero-structured nano-hybrids, in a “layer-by-layer” fashion. The CO2 adsorption capacity and multi-cycle stability of the LDH were both increased when supported onto GO because of enhanced particle dispersion. More recently, CuAl LDH/GO and CoAl LDH/GO hybrid materials with different LDH compositions were prepared. The as-synthesized hybrids and calcined composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermal analysis (TG), Brunauer-Emmett-Teller (BET-surface area), temperature programmed reduction (TPR) measurements. CuAl- and CoAl-LDHs have shown excellent yields (91% and 98%, respectively) in 25 min. reaction times. However, the mechanical properties of GO allows an enhancement of the stability of the catalyst that can be separated and reused in the reaction several times with a loss of activity as low as 70% of its initial value after five cycles.

Recent Publications

1. Xia Long, Zilong Wang, Shuang Xiao, Yiming An and Shihe Yang (2016) Materials Today: Transition metal based layered double hydroxides tailored for energy conversion and storage 19 (4):213-226.
2. M. Mokhtar, A. Inayat, J. Ofili, W. Schwieger (2010) Appl. Clay Sci. Thermal decomposition, gas phase hydration and liquid phase reconstruction in the system Mg/Al hydrotalcite/mixed oxide: A comparative study 50: 176-181.
3. Garcia Gallastegui, Ainara; Iruretagoyena, Diana; Gouvea, Veronica; Mokhtar, Mohamed; Asiri, Abdullah; Basahel, Sulaiman; Al-Thabaiti, Shaeel; Alyoubi, Abdulrahman; Chadwick, David; Shaffer, Milo (2012) Chem. Mater.: Graphene Oxide as support for Layered Double Hydroxides: enhancing the CO₂ sorption capacity 24: 4531-4539
4. Katabathini Narasimharao, Ebtisam Al-Sabban, Tamer Saleh, Ainara Garcia Gallastegui^, , Almudena Celaya Sanfiz, Sulaiman Basahel, Shaeel Al-Thabaiti, Abdulrahman Alyoubi, Abdullah Obaid, Mohamed Mokhtar(2013) Mol. Cat. A: Chem.: Microwave assisted efficient protocol for the classic Ullmann homocoupling reaction using Cu-Mg-Al hydrotalcite catalysts 379: 152-162.
5. Nesreen.S. Ahmed, Robert Menzel, Yifan Wang, Ainara Garcia-Gallastegui, Salem M. Bawaked, Abdullah Y. Obaid, Sulaiman N. Basahel, Mohamed Mokhtar (2016) J. Solid State Chem. Graphene-oxide-supported CuAl and CoAl layered double hydroxides as enhanced catalysts for carbon-carbon coupling via Ullmann reaction http://dx.doi.org/10.1016/j.jssc.2016.11.024

Biography:

Martha Ch Lux-Steiner completed her Graduation at Institute of Biomedical-Technology, and PhD at ETH Zurich, Switzerland. She completed her Post-doctoral Degree in Habilitation and Optoelectronics at University of Konstanz, Germany, where she worked from 1980 to 1995. In 1991, she was appointed as a Research Fellow in Department of Electrical Engineering at Princeton University, USA. She has been a Full Professor at Free University of Berlin and Head of the Institute for Heterogeneous Material Systems at Helmholtz-Zentrum Berlin, Germany since 1995. She is also a member of various international and national advisory boards and committees and was awarded several prizes.

Abstract:

Renewable energies are now established as main stream energy resources world-wide. The outlook at the market mainly depends on cost-competitiveness, policy initiatives and regulations, on energy security and environmental issues, as well as on availability to cover the global demands. Among the renewables in the electricity sector today, photovoltaic meet these key indicators exemplarily. Consequently, in the hi-Ren scenario of the International Energy Agency with an annual 6300 TWh electricity production PV provides 16% of global electricity by 2050. To satisfy such demands cost-effectively by established compound semiconductor solar cell base materials, the availability of resources from known economic reserves will be crucial, except that new routes of material savings need to be identified. In order to meet this challenge by cost-effective thin film photovoltaic, various technical approaches have to be considered and will be discussed in this presentation using Cu(In,Ga)(Se,S)2 technology, also named CIS technology, for example: Improving power conversion energy by advanced chemical material engineering and/or electrical device engineering applied to established macroscopic planar, single solar cell device configuration; reducing CIS film thickness without performance losses by means of advanced approaches in optical device engineering such as by implementation of micro- and nanostructures, plasmonics or photonics in single solar cell device configurations; improving power conversion energy by novel tandem photovoltaic concepts, consisting of monolithically stacked solar cells based on two different absorber materials, and furthermore; improving power conversion energy as well as saving material consumption by concentrating photovoltaics, particularly novel designs of microconcentrator photovoltaic concepts. Finally, a smart combination of the different approaches could be most effective. Thus, in addition to long-term stability of device performance, looking for appropriate compatible fabrication technologies will be necessary.

Recent Publications

Biography:

Michael K L Man studied in the Hong Kong University of Science and Technology and obtained his PhD degrees in Nano Science and Technology in 2011. Since 2012, he joined the Femtosecond Spectroscopy Unit in the Okinawa Institute of Science and Technology Graduate University as a postdoc and work on combining ultrafast optics techniques with electron microscopy in the study of time and spatially resolved electron dynamics. His research is in the area of surface physics using the low energy electron microscopy and photoemission electron microscopy techniques and a variety of other surface analytical tools. His research interests are in electron dynamics and transport, surface growth and diffusion, phase transition, magnetic and quantum electronic properties in 2D materials and ultrathin films.

Abstract:

Unveiling the fundamental mechanisms in semiconductor devices helps to unlock new paths toward better device performance and design. One of the key processes behind all device structures, is the internal motion of electrons through semiconductor materials due to applied electric fields or excitation of photocarriers. The ability to image the motion of electrons would further our understanding in these charge transfer processes, but requires both high spatial and time resolution. In the study of electron dynamics in materials, ultrafast optical techniques provide excellent temporal resolution, but are limited to spatial resolution. On the other hand, electron microscopy techniques provide very good spatial resolution, but offer poor temporal resolution. Here, by combining femtosecond pump-probe techniques with photoemission electron microscopy, we can track the motion of electrons through space and time, and gain access to the evolution of these electrons in energy and momentum space. In our recent publication, we have imaged the flow of electrons from high to low energy states in a InSe/GaAs semiconductor heterostructure shortly after photoexcitation, which essentially visualized the fundamental operating phenomena of solar cell devices. At the instant of photoexcitation, our measurement revealed the highly non-equilibrium distribution of photoexcited carriers in energy and space. Thereafter, in response to the out-ofequilibrium photocarriers, we observed the spatial redistribution of charges, which results in the formation of an internal electric fields that impede and finally stop the flow of electrons. By stitching together images taken at different time-delays, we created a movie lasting a few trillionths of a second of the electron transfer process in the photoexcited semiconductor heterostructure. Quantitative analysis and theoretical modeling of spatial variations in the video provide insight into operation of solar cells, the physics of 2D van der Waals materials, and other optoelectronic devices in general.

Recent Publications

1. M. K. L. Man, A. Margiolakis, S. Deckoff-Jones, T. Harada, E. Wong, M. B. M. Krishna, J. Madéo, A. Winchester, S. Lei, R. T. Vajtai, P.M. Ajayan and K.M. Dani, “Imaging the motion of electrons across semiconductor heterojunctions”, Nature Nanotechnology 183 (2016).
2. S. Deckoff-Jones, J. Zhang, C. E. Petoukhoff, M. K. L. Man, S. Lei, R. Vajtai, P. M. Ajayan, D. Talbayev, J. Madéo and K. M. Dani, “Observing the interplay between surface and bulk optical nonlinearities in thin van der Waals crystals”, Scientific Reports 6, 22620 (2016).
3. M. K. L. Man, S. Deckoff-Jones, A. Winchester, G. Shi, G. Gupta, A. D. Mohite, S. Kar, E. Kioupakis, S. Talapatra and K. M. Dani, “Protecting the properties of monolayer MoS2 on silicon based substrates with an atomically thin buffer”, Scientific Reports 6, 20890 (2016).
4. B. M. K. Mariserla, M. K. L. Man, S. Vinod, C. Chin, T. Harada, J. Taha-Tijerina, C. S. Tiwary, P. Nguyen, P. Chang, T. N. Narayanan, A. Rubio, P. M Ajayan, S. Talapatra and K. M. Dani, “Engineering Photophenomena in Large, 3D Structures Composed of Self-Assembled van der Waals Heterostructure Flakes”, Advanced Optical Materials 3, 1551-1556 (2015).
5. K.L. Man and M.S. Altman, “Small-angle lattice rotations in Graphene on Ru(0001)”, Phys. Rev. B 84, 235415 (2011).

Biography:

Margarita Russina has completed her PhD from Technical University Berlin and postdoctoral studies from Los Alamos National Laboratory (USA). She is the leader of Neutron Time-Of-Flight Spectroscopy group at Helmholtz Centre Berlin Material and Energy Research. She has published more than 60 papers in reputed journals.

Abstract:

Safe and effective hydrogen storage is widely recognized as a key technology for hydrogen economy in the 21st century, with porous materials being one of the highly potential storage media. The successful synthesis and design of new materials dictate however the necessity of systematic studies of the storage processes and fundamental understanding of molecular processes involved. We have explored the microscopic mechanism of hydrogen storage in pores of sub-nanometer size in broad range of materials, namely ice-based clathrates, recently synthesized CAU-1 metallic organic framework and porous carbide derived carbon (CDC) with help of neutron scattering techniques. The ability of neutrons to probe both microscopic structure and dynamics combined with high sensitivity to hydrogen makes neutron scattering a powerful tool in the exploration of the confined hydrogen behavior. Our results show that confinement leads to strong variation of molecular mobility as a function of pore size and can be reduced or enhanced
compared to those in the bulk solid at the same temperatures. Secondly, hydrogen storage can be improved by smart tuning of the guest-host and guest-guest interactions. In CAU-1 metallic organic framework we have observed a formation of the hydrogen bonds between hydrogen and linkers and strong guest-guest correlations leading to the shrinking of the host framework structure and rearrangements of confined molecules. In extreme cases the contraction of the framework can lead to the expulsion of the gas from the pore. The moderate deformation however promotes the formation additional occupational positions and increase of hydrogen intake.

Biography:

Shin’ichi Nakatsuji obtained his PhD from Osaka University on the chemistry of dehydroannulenes in the field of structural organic chemistry. After studied as a JSPS postdoctoral fellow at the same university, he joined Faculty of Pharmaceutical Sciences at Nagasaki University, first as an assistant then as an associate professor and worked in the field of dye chemistry and organic analytical chemistry. He worked one year at TH (now TU) Darmstadt in west Germany as an Alexander von Humboldt fellow. He then moved to the newly founded Faculty of Science at Himeji Institute of Technology (since 2004 University of Hyogo), where he has initiated the studies on the development of new functional organic materials, such as organic conductors, organic magnetic materials, liquid crystals, and organic batteries. He has recently been retired the university and is now a professor emeritus. He has published over 220 scientific papers and has been awarded the distinction of Doctor Honoris Causa from Technical University of Iasi in Romania.

Abstract:

Rechargeable batteries are widely used not only in portable equipments like cell phones or personal computers but also as the energy sources of automobiles and among them lithium-ion battery (LIB) technology is currently considered to constitute a reliable system for electricity storage with high energy density and design flexibility. Along with the development of such inorganicbased rechargeable batteries as LIB, it is of growing interest to develop organic-based ones for the next generation to improve the battery-performances by possible flexibilities of organic materials from chemical and physical viewpoints. We have been interested in developing new organic radical batteries containing dual redox units, i. e., a nitroxide radical together with another redox group such as ferrocene, 1,4-benzoquinone, anthraquinone, naphthalenediimide, or disulfide to increase the charge storage capacities and to obtain unique charging-discharging properties. We wish to report in this paper some of our recent results in the development of novel organic radical batteries incorporating a nitroxide radical and another redox unit. The development of new dye salts with a radical unit will also be reported at the same time that are expected to show relevant redox and photosensitizing properties useful for dye-sensitizing solar cells (DSSCs).

Recent Publications

1. Kao S -J, Kawahara Y, Nakatsuji S, Ho K -C (2015) Achieving a large contrast, low driving voltage, and high stability electrochromic device with a viologen chromophore. Journal of Materials Chemistry C 3:3266-3272.
2. Fujikura K, Akutsu H, Yamada J, Nakatsuji S, Satoh M (2015) Structures and properties of diradical compounds containing disulfide and nitroxide groups. Synthetic Metals 208:17-20.
3. Nakatsuji S, Fujiwara K, Akutsu H, Yamada J, Satoh M (2013) Structures and properties of ferrocene derivatives with different kinds of nitroxide radicals. New Journal of Chemistry 37:2468-2472.
4. Suzuki S, Kawahara Y, Akutsu H, Yamada J, Nakatsuji S (2013) Structures of the reaction products of AZADO radical with TCNQF₄. Beilstein Journal of Organic Chemistry 9:1487-1491.
5. Nakatsuji S, Aoki K, Kojoh A, Akustu H, Yamada J, Karakawa M, Aso Y (2013) Self-Assembling Aryl-Naphthalendiimide Derivatives with a Nitroxide Radical. Asian Journal of Organic Chemistry 2:164-168.

Biography:

Zhiqiang Gao is an Associate Professor in Department of Chemistry at National University of Singapore (NUS). He completed his BSc and PhD in Chemistry at Wuhan University. He worked as a Postdoctoral Fellow at Åbo Akademi University and Weizmann Institute of Science. After spending three years in the United States and eight years at Institute of Bioengineering and Nanotechnology, he joined NUS in April 2011. His research interest includes “Bioengineering, renewable energy, electrochemistry, analytical chemistry and materials science”.

Abstract:

Lithium-ion batteries (LIBs) are extensively used from portable electronic appliances such as in mobile phones and laptops to bulky items such as in electric vehicles and large-scale energy storage. The extensive usage of LIBs for various energy storage purposes is due to their high energy and power densities. Their ability to store three times more energy than other batteries increases their competitiveness coupled with the virtual lack of waste during mining. Unfortunately, due to the rapid increase in demand for lithium and the geographical scarcity of it as the bulk availability of lithium reserves is found in South America. Therefore, there is an urgent need for an alternative source of lithium in the manufacture of rechargeable batteries. Sodium ion batteries (SIBs) have attracted considerable attention in recent years due to the high abundance, scattered distribution and low cost of sodium. Based on the concept of nano-confinement reaction, a synthetic strategy is developed to construct an ultrathin carbon film-coated and nanostructured nickel sulfide anchored on carbon nanotubes (CNTs). The synthesis involves direct growth of nickel hydroxide on the CNTs followed by dehydration, sulfidation and carbon coating. When used as an anode material in SIBs, the nickel sulfide-based anode shows a high utilization rate of active material and a favorable specific capacity of 390 mAh g-1. The excellent performance of the nickel sulfidebased anode in SIBs demonstrates the potential of nickel sulfide to be used as the anode material in SIBs when it is engineered to alleviate its structural constraints. In principle, this strategy can be conveniently adapted to engineer other transition metal-based materials for applications in energy storage.

Recent Publications

1. Han F, Tan C, Gao ZQ (2016) Improving the Specific Capacity and Cyclability of Sodium-Ion Batteries by Engineering a Dual-Carbon Phase-Modified Amorphous and Mesoporous Iron Phosphide. ChemElectroChem 3:1054–1062.
2. Yang XJ, Gao ZQ (2015) Enzyme-Catalyzed Deposition of Ultrathin Silver shells on Gold Nanorods: A Universal and Highly Efficient Signal Amplification Strategy for Translating Immunoassay into Litmus-type Test. Chemical Communications 51:6928–6931.
3. Yang XJ, Gao ZQ (2015) Silver/Gold Core-Shell Nanoprism-Based Plasmonic Nanoprobes for Highly Sensitive and Selective Detection of Hydrogen Sulfide. Chemistry- A European Journal 21:988–992.
4. Lim SY, Shen W, Gao ZQ (2015) Carbon Quantum Dots and Their Applications. Chemical Society Reviews 44:362–381.
5. Shen W, Gao ZQ (2015) Quantum Dots and Duplex-Specific Nuclease Enabled Ultrasensitive Detection and Serotyping of Dengue Viruses in One Step in a Single Tube. Biosensors and Bioelectronics 65:327–332.

Biography:

Zhu’s research efforts were devoted to fabricate multi-scale and multi-functionalized conducting polymer nanostructures (e.g. polyaniline) self-assembled by template-free method, and exploit their potential applications in electrochemical energy conversion and storage. She developed a simple, universal and controllable method for constructing the hierarchical and multi-functionalized 3D-microstructures self-assembled from 1D-nanostructures by a cooperation effect between the micelle soft-templates and self-assemble driving forces. She found that the aligned polyaniline or polypyrrole nanowires or PEDOT nanostrutures can be acted as electrodes for enhancing the oxygen reduction reaction, electron transfer of bacteria, and improving electrochemical performance of supercapacitors. These findings expend the application of conducting polymer nanostructures in electrochemical energy conversion and storage.

Abstract:

The heterocyclic conjugated polymers, including polyaniline (PANI), polypyrrole (PPy) , and poly(3,4-ethylenedioxythiophene) (PEDOT), have recently been investigated as inexpensive electro-catalysts because of their low cost, high electronic conductivity, and distinct redox properties. Generally speaking, these polymers can act as electrochemical catalysts in the following three ways: 1) as catalysts on their own, 2) as precursors for pyrolyzed M-Nx/C catalysts, and 3) as matrix for entrapping non-precious metals, 4) Conducting polymers with its micro/nanostructures over a large surface area can itself be an outstanding intrinsic electrochemical catalyst. We have developed a new class of efficient non-precious-metal ORR catalysts by doping PEDOT with hemin via a one-step self-assembling mothod. It is demonstrated that the hemin-induced synergistic effect results a very high 4-electron oxygen reduction reaction (ORR) activity, a better stability, and free-from methanol crossover effect even in a neutral phosphate buffer solution due to hemin molecular characteristic, in which the iron centre of Fe-N 4 –C served for ORR, while the carboxyl groups used dopant for conducting PEDOT. Moreover, PANI nanofibers fabricated by electrochemical polymerization of aniline can act as a solid-state polymeric mediator for bacterial extracellular electron transfer (EET), which enables not only the dramatically enhanced EET current at a certain potential but also tunable EET behavior in a controlled manner.

Recent Publications

1. Chunmei Ding, Huan Liu, Ying Zhu*, Meixiang Wan, Lei Jiang (2012) Energy Environ. Sci., 5:8517-8522
2. Z. Guo, H. Liu, C. Jiang, Y. Zhu*, M. Wan, L. Dai, L. Jiang (2014) Small, 10:2087-2095.
3. Guangyuan Ren, Yunan Li, Zhaoyan Guo, Guozheng Xiao, Ying Zhu*, Liming Dai, Lei Jiang, (2015)Nano Research, 8: 3461-3471.
4. Chun-mei Ding, Mei-ling Lv, Ying Zhu, Lei Jiang, and Huan (2015) Angew. Chem. Int. Ed. 54:1446-1451.
5. Zhaoyan Guo, Guangyuan Ren, Congcong Jiang, Xianyong Lu, Ying Zhu*, Lei Jiang, Liming Dai (2015) Scientific Reports, 5:17064.
6. Zhaoyan Guo, Zhen Xiao, Guangyuan Ren, Guozheng Xiao, Ying Zhu*, Liming Dai* and Lei Jiang (2016) Nano Research, 9:1244-1255.

Biography:

Akhilesh Babu Ganganboina studied Biotechnology in Vellore Institute of Technology, India where he obtained his Masters degree in 2012. Then he worked at Strand Life Sciences and in 2015 moved to National Tsing Hua University, Taiwan, where he now is pursuing PhD degree in department of Biomedical Engineering and Environmental Sciences under the guidance of Prof. RA Doong. His research interests lie in nanomaterial fabrication and application of energy and sensing.

Abstract:

There is a demanding need for energy storage alternatives materials that provide new solutions for environmental concerns in emerging technologies as well as high capacitance value over a long cyclic period. We are reporting an environmental friendly nanocomposite of halloysite-graphene quantum dots (HNT-GQD) synthesized by a newly developed method to provide increased charge storage sites and allow fast charge transport for supercapacitor application The HRTEM images show that the 5-10 nm sized GQDs are homogeneously distributed on the surface of Halloysite which resulted in increased utilization efficiency of GQDs. The combination of different physical and chemical properties of Halloysite and GQD, like high ion storage density, surface area, rapid ion transport etc, makes the HNT-GQD to high specific capacitance in neutral electrolyte solution, Na2SO4 with energy density of 50.03 Wh/kg and also excellent capacitance retention after 5000 charge-discharge cycles. These performance features are superior among those reported for halloysite or GQD based supercapacitors, making it a promising candidate for next generation, environmental friendly and high performance electrochemical energy storage material.

Recent Publications

1. Akhilesh Babu G, Pooja Shrisvastava, Priyanka Srivastava and Ramaballabha Sahu (2013)  Effect of Recklessly Silver Nanoparticles from laboratory on Vigna Raduata, Brassica Juncea, Rhizosphere Flora and Drosophila melanogaster. International Journal of Pharma and Bio Sciences. 4(3): (B) 590 - 601
2. Akhilesh B G, Dutta Chowdhury A, Doong R A (2016) Graphene Quantum Dots Layered Halloysite Nanotubes for Enhanced Supercapacitor Electrode Material (Manuscript under submission)
3. Dutta Chowdhury A, Akhilesh B G, Doong R A (2016) Doxorubicin Conjugated Fe₃O₄-GQD Nanoparticle for Magnetically Targeted and pH Responsive Drug Delivery Vehicle: A Two Way Targeted Approach (Manuscript under preparation)
4. Akhilesh B G, Doong R A (2016) Tunable Halloysite Nanotube Surface with Iron Oxide and Graphene Quantum Dots for superior Supercapacitor Electrode Material (Manuscript under preparation)

Biography:

Kazuki Morita took bachelor degree in 1983, master degree in 1985, and Doctor of Engineering in 1988 from the University of Tokyo at the Department of Metallurgy. He has his expertise in physical chemistry on high temperature materials processing mostly related to iron- and steelmaking, silicon refining, and materials recycling as a professor at the Department of Materials Engineering in the University of Tokyo. His reported thermodynamic data on impurities in molten silicon has clarified the validity of new metallurgical processes for solar grade silicon refining. In addition, he and his students pursued innovative processes for more effective silicon refining via new principle, one of which is widely known as a solvent refining process with a possibility of higher refining efficiency and lower processing temperature.

Abstract:

Solar power has been widely introduced as a renewable energy lately. Among others, silicon via a gasification-distillation method is yet the main feedstock for ordinary solar cells, but more economical production process with higher productivity has been strongly desired. As a new promising route for solar grade silicon (SOG-Si) production, metallurgical refining processes was developed in the early eighties of the last century, followed by the establishment of NEDO-JFE process in the beginning of the 2000s, where P was removed by electron beam (EB) in vacuum conditions and B by Ar-H2O plasma. In order to verify and optimize the process thermodynamic properties of noticeable impurities in molten silicon, such as P, B, Fe, Ti, Ca, Al and Mg, were clarified by our research group. Then, we have thermodynamically assessed the possibility of impurity removal by alternative processes, such as slag treatment and acid leaching. Furthermore, as an innovative process, we have introduced an alloying process for reducing the process temperature as well as the solubility limit of impurities in solidification refining. We developed the process from Si-Al melts and now being called “solvent refining process” and further developed also by several research groups. In recent years, we have investigated the possibility of B removal by Si-Sn solvent system and the combination with slag treatment seems to be the most effective process, whose B removal efficiency has never been attained before. Including other refining processes developed in our research group, the possibility of new metallurgical processes for solar cell silicon production will be reviewed from a physicochemical view point in the presentation.

Recent Publications

1. Morita K, Miki T (2003) Thermodynamics on Solar-Grade-Silicon Refining. Intermetallics 11:1111-1117.
2. Yoshikawa T, Morita K (2009) Refining of Silicon during Its Solidification from a Si-Al Melt.    Journal of Crystal Growth 311: 776-779.
3. Teixeira LAV, Morita K (2009) Removal of Boron from Molten Silicon Using CaO–SiO₂ Based Slags. ISIJ International 49:783-787.
4. Nishi Y, Kang Y, Morita K  (2010) Control of Si Crystal Growth during Solidification of Si-Al Melt. Materials Transaction 51: 1227-1230.
5. Ma X, Yoshikawa T, Morita K (2014) Purification of Metallurgical Grade Si Combining Si–Sn Solvent Refining with Slag Treatment.    Separation and Purification Technology 125: 264-268
6. Wang Y, Ma X, Morita K (2014) Evaporation Removal of Boron from Metallurgical-Grade Silicon Using CaO-CaCl₂-SiO₂ Slag.              Metallurgical and Materials Transactions B 45B:334-337
7. Lei Y, Ma W, Sun L, Dai Y, Morita K (2016) B Removal by Zr Addition in Electromagnetic Solidification Refinement of Si with Si-Al Melt.        Metallurgical and Materials Transactions B 47B: 27-31

Biography:

Peng-Sheng Wei received Ph.D. in Mechanical Engineering Department at University of California, Davis, in 1984. He has been a professor in the Department of Mechanical and Electro-Mechanical Engineering of National Sun Yat-Sen University, Kaohsiung, Taiwan, since 1989. Dr. Wei has contributed to advancing the understanding of and to the applications of electron and laser beam, plasma, and resistance welding through theoretical analyses coupled with verification experiments. Investigations also include studies of their thermal and fluid flow processes, and formations of the defects such as humping, rippling, spiking and porosity. Dr. Wei has published more than 80 journal papers, given keynote or invited speeches in international conferences more than 80 times. He is a Fellow of AWS (2007), and a Fellow of ASME (2000). He also received the Outstanding Research Achievement Awards from both the National Science Council (2004), and NSYSU (1991, 2001, 2004), the Outstanding Scholar Research Project Winner Award from National Science Council (2008), the Adams Memorial Membership Award from AWS (2008), the Warren F. Savage Memorial Award from AWS (2012), and the William Irrgang Memorial Award from AWS (2014). He has been the Xi- Wan Chair Professor of NSYSU since 2009, and Invited Distinguished Professor in the Beijing University of Technology, China, during 2015-2017.

Abstract:

Resistance spot welding is an important technique often used in joining thin workpieces in various aerospace, automobile and manufacturing technologies. The process involves complicated magneto-fluid dynamics, heat transfer, metallurgy, physics and chemistry, etc. This presentation theoretically and quantitatively investigates and interprets processes by realistically accounting for transient magneto-fluid mechanics, heat and species transport, and bulk resistance in workpiece, and film and constriction resistances at contact interfaces. Contact resistances are functions of temperature, hardness, contact spots, etc. Since temperature gradient and solidification rate are found, the computed morphological parameter reflecting constitutional supercooling shows that different microstructures such as planar, columnar microstructures, columnar dendrite, equiaxed grains of the weld nugget can be interpreted, predicted and controlled.

Recent Publications

1. Wei PS, Chao TC (2016) The effects of drilling parameters on pore size in keyhole mode welding. ASME Journal of Manufacturing Science and Engineering 138: 021008.

2. Chen SJ, Wang LW, Wei PS, Xiao, J, Jia YZ, Su S(2016) Sustaining the inter-wire arc in twin-wire indirect arc welding. Journal of Manufacturing Processes 21: 69-74.

3. Wei PS, Chang CC(2016) Existence of universal phase diagrams for describing general pore shape resulting from an entrapped bubble during solidification. ASME Journal of Heat Transfer 138: 104503.

4. Wei PS, Hsiao SY(2016) Effects of mass transfer coefficient on pore shape in solid. International Journal of Heat and Mass Transfer 103: 931-939.

5. Wei PS, Hsiao SY (2016) Effects of solute concentration in liquid on pore shape in solid. International Journal of Heat and Mass Transfer 103: 920-930

Biography:

Masayuki Suda is an Assistant Professor at Research Center of Integrative Molecular Systems, Institute for Molecular Science, Japan. He has his expertise in “Photo-functional magnetic and conducting molecular devices”. He developed new photo-control method for organic-inorganic interface dipoles which can modulate the magnetic or conducting properties at the device interfaces. He recently applied this method to the field-effect transistor devices based on organic Mott insulators and realized first light-induced superconductivity in organic materials. In recognition of this achievement, he won PCCP award from Royal Society of Chemistry in 2016.

Abstract:

Recently, electric-double-layers (EDL) of ionic liquids with huge capacitance have been employed in superconducting field-effect transistors as a nano-gap capacitor. However, due to the freezing of the ionic motions below ~200 K, modulations of the carrier density so far have been limited to the high-temperature regime. In this study, we fabricated novel photo-active superconducting devices by laminating a single crystal of κ-(BEDT-TTF)2Cu[N(CN)t]Br on the substrates coated with self-assembled monolayer of spyropiran-derivatives (SP-SAM). The initial resistances for the devices showed Mott insulator phase in the resistance measurements. After UV irradiation, however, superconducting transition was clearly observed. This photo-induced superconducting phase remained even after the irradiation was stopped. The resistance recovered to nearly the initial value by visible light irradiation, showing a reversible switching capability. From our previous measurements, κ-Br is known to evoke superconductivity by electrostatic carrier doping. The above reversible switching of superconductivity should also be due to a carrier doping by the formation of EDL at the interface. Indeed, spyropirans can switch between a non-ionic isomer and a zwitterionic isomer when triggered by light-irradiation with different wavelengths, resulting in a significant change in the electric dipole moment. Reversible changes in dipole moment of SP-SAM produced two distinct electric fields between the κ-Br and the substrates that created electrostatically doped carriers. Thus, superconductivity could be switched by photo-irradiation by photo-induced EDL formation. This result opens new possibilities for the novel electronics utilizing a photo-active electric double layer which can modulate electric-fields by light irradiation.

Recent Publications

1. Suda M et al. N-type superconductivity in an organic Mott insulator induced by light-driven electron-doping. (2016) submitted.
2. Suda M, Kato R, Yamamoto HM (2015) Light-induced superconductivity using a photoactive electric double layer. Science 347:743-746.
3. Suda M et al. (2014) Strain-tunable superconducting field-effect transistor with an organic strongly-correlated electron system. Advanced Materials 26:3490-3495.
4. Yamamoto HM, Suda M et al. (2013) A strained organic field-effect transistor with a gate-tunable superconducting channel. Nature Communications 4:2379.
5. Tajima N, Suda M et al. (2013) Quantum Hall effect in multilayered massless Dirac fermion systems with tilted cones. 88:075315.

Biography:

Hideo Kaiju received his Ph. D. from Keio University in 2005. During the doctor course, he worked as a research fellow of the Japan Society for the Promotion of Science (JSPS). He worked as a research associate from 2004-2007 and an Assistant Professor from 2007-2013 in Research Institute for Electronic Science (RIES) at Hokkaido University. From 2009-2013, he also worked as a Precursory Research for Embryonic Science and Technology (PRESTO) researcher of Japan Science and Technology Agency (JST). From 2013 to the present, he worked as an Associate Professor in RIES at Hokkaido University. He pioneered tunnel magnetocapacitance (TMC) in magnetic tunnel junctions (MTJs), and recently he achieved the largest TMC in MgO-based MTJs. He is interested in such spintronic devices, including magnetoimpedance devices, magnetic nanoscale junctions, molecular spin devices, and laser-induced magnetic materials.

Abstract:

Spintronics is an emerging research field which utilizes the charge and spin degrees of freedom of electrons in solid-state systems and devices. One of the most successful devices in spintronics is the magnetic tunnel junction (MTJ), which consists of two ferromagnetic layers separated by a thin insulator. MTJs show a large tunnel magnetoresistance (TMR) effect at room temperature [Nat. Mater. 3, 868 (2004)]. At present, the TMR ratio has reached up to 600% in MTJs with MgO tunnel barriers [Appl. Phys. Lett. 93, 082508 (2008)]. On the other hand, MTJs also exhibit tunnel magnetocapacitance (TMC) effect at room temperature [J. Appl. Phys. 91, 7430 (2002), Appl. Phys. Lett. 90, 142105 (2007)]. Recently, we have observed a large TMC ratio beyond 150%, which is three times larger than the conventional value, at room temperature in MTJs with MgO tunnel barriers [Appl. Phys. Lett. 107, 132405 (2015)]. We have also found that the mechanism of TMC effect can be well explained by the theoretical calculation based on Debye- Fröhlich model. This calculation predicts that the TMC ratio can be as large as about 1000% for a spin polarization of 87%, while the TMR ratio is 623% for the same spin polarization. These theoretical and experimental findings provide a deeper understanding on AC spin-dependent transport in MTJs and will open up wider opportunities for device applications, such as highly sensitive magnetic sensors and impedance-tunable devices. Furthermore, MC effect has also been observed in molecular spin valves [SPIN 4, 1440015 (2014)], magnetic nanoscale granular solids [Nat. Commun. 5, 4417 (2014)], and magnetic single electron transistors [Sci. Rep. 5, 13704 (2015)]. Rapid progress is now being made in the research field on MC effect. In this talk, we focus on MC effect in spintronic devices and present the recent progress in this field.

Recent Publications

1. T. Misawa, S. Mori, T. Komine, M. Fujioka, J. Nishii, and H. Kaiju, Appl. Surf. Sci. 390, 666 (2016).
2. H. Kaiju, M. Takei, T. Misawa, T. Nagahama, J. Nishii, and G. Xiao, Appl. Phys. Lett.  107, 132405 (2015).
3. H. Kaiju, H. Kasa, T. Komine, S. Mori, T. Misawa, T. Abe, and J. Nishii, J. Appl. Phys. 117, 17C738 (2015).
4. H. Kaiju, Y. Yoshida, S. Watanabe, K. Kondo, A. Ishibashi, and K. Yoshimi, J. Appl. Phys. 115, 17B901 (2014).
5. Y. Yoshida, K. Oosawa, S. Watanabe, H. Kaiju, K. Kondo, A. Ishibashi, and K. Yoshimi, Appl. Phys. Lett. 102, 183109 (2013).

Biography:

Eunsoo Choi is a Professor of Civil Engineering at Hongik University, Korea; Director of Korean Society of Steel Construction; board member of Korea Institute for Structural Maintenance and Inspection and; Director of Korea Railway Association. He completed his Doctorate Degree in Department of Civil and Environmental Engineering at Georgia Institute of Technology. He contributed greatly to the advancement of technology of seismic capacity assessment and seismic retrofit in the Central East region, USA. Afterward, he has started his research on “Applying shape memory alloy to civil engineering fields for the first time in Korea” and has lots of papers and patents regarding the fields.

Abstract:

This study was conducted to investigate the crack-closing capacity of super-elastic shape memory alloy (SE SMA) short fibers embedded in mortar beams. For this purpose, NiTi SMA fibers with a diameter of 0.995 mm and a length of 36-42mm were used. Four types of SMA fibers were prepared, namely, straight (RF, reference), L-shaped (LS), double L-shaped (DL) and spear-headshaped (SH). Before the crack-closing test, a pullout test of each type of fibers was conducted to check the interfacial bond strength between the fiber and mortar matrix. The dimensions of the cement mortar beam are 40 mmx40 mmx160 mm (BxHxL). Two SE SMA fibers were placed at the bottom center of the beams along with an artificial crack-guidance-film of 10 mm depth and 1mm thickness. From the hysteretic bending test, this paper evaluated the crack-closing capacity by comparing with the deflections upon loading and unloading. From the pullout test, it was covered that the only SH fiber could generate the super-elastic behavior due to the sufficient bond resistance although there was a small initial slip of fiber. However, the initial slip was critical cause of failure for the crack to be closed upon unloading condition. For the flexural crack control, only a perfect bond between SE SMA short fiber and mortar matrix can generate the super-elastic behavior of the beam.

Recent Publications

1. Choi E, Kim DJ, Hwang JH, and Kim WJ (2016) Prestressing effect of cold-drawn short NiTi SMA fibres in steel reinforced mortar beams, Smart Materials, and Structures, 085041 (13pp).
2. Choi E, Kim DJ, Chung YS, Kim HS, and Jung CS (2015) Crack-closing of cement mortar beams using NiTi cold-drawn SMA short fibers, Smart Materials, and Structures, 015018 (11pp).
3. Choi E, Kim DJ, Youn HJ, and Nam TH (2015) Repairing crack developed in mortar beams reinforced by cold-drawn NiTi or NiTiNb SMA fibers, Smart Materials and Structure, 125010 (13pp).
4. Choi E, Kim D, Lee JH and  Ryu GS (2017) Monotonic and hysteretic pullout behavior of superelastic SMA fibers with different anchorages, Composites Part B, 108:232-242.
5. Choi ES, Youn HJ, and Cho BS (2016) Probabilistic seismic performance assessment of lap-spliced RC columns retrofitted by steel wrapping jackets, EARTHQUAKE ENGINEERING AND ENGINEERING VIBRATION, 15:1.

Biography:

Mikhail Lebyodkin has completed his PhD at Moscow Institute of Physics and Technology in 1989. He started his career at Research Institute of Solid State Physics- Russian Academy of Sciences. He completed his Doctor of Science in 2002. He is a Research Director at French National Centre for Scientific Research (CNRS), appointed in Laboratory of Microstructures and Mechanics of Materials (LEM3), University of Lorraine. He is currently Head of LEM3. His main research interests include “Mechanical behavior of materials, self-organization of crystal defects, and relationships between mechanical and physical properties (magnetic, electric) of solids”.

Abstract:

The interest to jerky flow in dilute alloys or the Portevin-Le Chatelier (PLC) effect has not diminished since it was discovered a century ago. One reason for such sustaining interest is that the PLC effect is undesirable in practice since it impedes the formability of alloys. On the other hand, it is a striking example of dislocations self-organization that gives rise to a complex strain heterogeneity evolution and serrated deformation curves. The microscopic mechanism of plastic instability is understood rather well and is generally attributed to dynamical pinning of dislocations by solute atoms. Indeed, since this additional pinning is controlled by a balance between the solute diffusion rate and the plastic strain rate, it leads to a negative resistance of the material to loading: the stronger the strain rate, the lower the deforming stress. The feature of negative resistance is a well-known mobile of unstable behavior of dynamical systems. However, the knowledge of the microscopic mechanism is insufficient to model real behavior which requires understanding the instability development involving complex collective dynamics of dislocations. The observed behaviors depend on the strain rate, temperature, microstructure and even the scale of observation, but display some reproducible features that testify the existence of specific dynamical mechanisms. Uncovering these mechanisms has become one of important fields of research since two decades. In the present paper, the PLC effect is investigated using statistical analysis of plastic activity in Al-Mg alloys on distinct scales of observation, namely, the macroscopic scale of stress serrations and a mesoscopic scale pertaining to the accompanying acoustic emission, as well construction of spatiotemporal patterns characterizing the local strain field evolution. In particular, it is found that the extreme grain refinement by recently developed methods of severe plastic deformation strongly affects the dynamical mechanisms controlling the unstable plastic flow.

Recent Publications

1. Lebyodkin MA, Shashkov IV, Lebedkina TA, Mathis K, Dobron P, Chmelik F (2013) Role of superposition of dislocation avalanches on the statistics of acoustic emission during plastic deformation. Phys. Rev. E 88: 042402.

2. Lebedkina TA, Lebyodkin MA, Lamark TT, Janecek M, Estrin Y (2014) Effect of equal channel angular pressing on the PortevinLe Chatelier effect in an Al3Mg alloy. Mater. Sci. Eng. A 615: 7-13.

3. Zhemchuzhnikova D, Lebyodkin M, Lebedkina T, Kaibyshev R (2015) Unusual behavior of the Portevin-Le Chatelier effect in an AlMg alloy containing precipitates. Mater. Sci. Eng. A 639: 37-41.

4. Abobaker M, Bouaziz O, Lebyodkin M, Lebedkina T, Shashkov IV (2015) Avalanche dynamics in crumpled aluminum thin foils. Scripta Mater. 99: 17-20.

5. Amouzou K, Richeton T, Roth A, Lebyodkin M, Lebedkina T (2016) Micromechanical modeling of hardening mechanisms in commercially pure alpha-titanium in tensile condition. Intern. J. Plasticity 80: 222-240.

Biography:

Daniel Melling works to develop medical technology and surgical devices at Institute of Medical Science and Technology (IMSaT), Dundee, UK. After working at Polymer and Pharmaceutical industries, he completed his PhD on “The development and characterization of new forms of conducting polymers for use as microactuators at Linkoping University, Sweden. He is currently working on the development of medical polymers at IMSaT where he is the Head of the Medical Polymer and Smart Materials laboratory. He is particularly interested in “The development of medical applications of conducting polymers and composites”.

Abstract:

Smart-materials based on conducting polymers (CPs) such as polypyrrole (PPy) are currently being used to develop micro-actuators for cell biology applications, such as the electrical and mechanical stimulation of stem cells. Such materials must be capable of long term, stable actuation in within biological fluids and cell culture media. Unfortunately, devices employing CPs are often demonstrated over a relatively small number of cycles, during which time any deterioration in their behavior is not always evident. For example CP films based on PPy (DBS) typically display a large decrease in performance when actuated over several days actuated in saline solutions. This can be attributed to the loss of unbound oligomer and dedoping of counter ions from within the polymer film. There is clearly a need to develop CP films that can be actuated within biological fluids and cell culture media with little deterioration of performance during the lifetime of the device. We have employed a relatively new approach, Laser Scanning Micrometry (LSM), to characterize the electrochemomechanical behavior of actuating CP films based on PPy. The films have been synthesized over a range of different conditions and actuated in biologically relevant conditions. Our aim has been to improve the actuation performance of CP films when actuated over long periods of time (days) in aqueous based electrolytes that model biological fluids. We will describe how we have used LSM to implement synthetic strategies and develop new CP materials for the production of actuating films with improved long term performance. In this respect, LSM has proven to be a valuable tool for the study, characterization and development of CP actuating films.

Recent Publications

1. Melling D, Wilson S A, Jager E W H (2015) Controlling the electro-mechanical performance of polypyrrole through 3- and 3, 4-methyl substituted copolymers. RSC Advances, 5: 84153-84163.
2. Melling D, Wilson S, Jager E W H (2013) The effect of film thickness on polypyrrole actuation assessed using novel non-contact strain measurements. Smart Materials and Structures, 22.
3. Melling, D., Wilson, S., Berggren, M., Jager, E. W. H. (2011) Altering the structure of polypyrrole and the influence on electrodynamic performance. Electroactive Polymer Actuators and Devices (EAPAD), Proc. Of SPIE, Vol. 7976, Art. No. 79760Z, DOI: 10.1117/12.880277.
4. Melling D, Jager E W H (2016) Conducting Polymers as EAPs: Characterisation Methods and Metrics. Electromechanically Active Polymers: A Concise Reference (Polymers and Polymeric Composites: A Reference Series), Publisher: Springer, pp.740, DOI: 10.1007/978-3-319-31767-0_14-1.
5. Gursel Alici, Rahim Mutlu, Melling D, Keiichi Kaneto, Jager E W H (2016) Conducting Polymers as EAPs: Device Configurations. Electromechanically Active Polymers: A Concise Reference (Polymers and Polymeric Composites: A Reference Series), Publisher: Springer, p1-35, DOI: 10.1007/978-3-319-31767-0_12-1.

Biography:

Norbert Schwarzer completed his Graduation in Physics at University of Chemnitz in 1991. After completing several research projects abroad and PhD in the field of Contact Mechanics in 1998, he became an Assistant Professor at University of Chemnitz in 1999. In 2005, he founded the Saxonian Institute of Surface Mechanics in Eilenburg/Germany. He published a variety of papers mainly in the fields of basic research and application of contact mechanical approaches for laminates, composites and layered materials.

Abstract:

Optimization tools for improved material development (e.g. protective coatings) do not only require a comprehensive mechanical contact model but also need to account for the principle uncertainties residing in the field. It will been shown that the classical continuum mechanical and thus, naturally deterministic, concepts are not adequate if one intends to holistically describe the uncertainties coming into play with applications connected with tribological processes like erosion, fretting, wear etc. This also and especially holds in the case of bio-applications as the living systems provide a kind of natural, omnipresent and very dominant uncertainty. By incorporating quantum mechanical concepts via a principle scale dependent accessibility with respect to input parameters from measurement, surface roughness or even non-continuous composition, one does not only overcome such flaws in the classical approaches but also automatically incorporates a method to observe and actively control the influence of the uncertainty budget. According to the classical quantum mechanics, the uncertainty is been accounted for by a “Planck” constant, only that this time, depending on the dimension of the problem, we end up with Planck-vectors or tensors instead of the classical scalar. The way to go is cumbersome at the beginning, because it requires the principle quantization of the line element of a general continuous space, but the outcome is a very compact, rather general and powerful tool to handle practical applications. As a byproduct, the quantization of the Einstein field equations can be achieved.

Recent Publications

1. N. Schwarzer: „Quantum Tribology – Part I: Theory

2. N. Schwarzer: „Recipe to Quantize the General Theory of Relativity

Biography:

Gregory Leitus is an associated Staff Scientist at Weizmann Institute of Science. He has his expertise in Material Science, especially in the fields of “Magnetic and superconducting properties of materials, magnetic and electric transport measurements and crystallography”. He is the Co-author of 165 publications in reviewed scientific journals.

Abstract:

With the aim to orienting WS2 nanotubes in molten polymer phases by application of a magnetic field, a new synthetic strategy was used to decorate the surface of WS2 nanotubes with FeWO4 nanoparticles. Nanoparticles FeWO4 were obtained by depositing amorphous iron oxide film onto surface of the WS2 nanotubes with subsequent high temperature annealing. Some different phases are forming during the process of phase transformations and they definitely manifest themselves by their different magnetic properties. The nanotubes could be oriented by moderate magnetic field (0.3 T) in low viscosity fluids like ethanol.

Recent Publications

1. Levi R, Bitton O, Leitus G, Tenne R, Joselevich E, (2013) Field-effect transistors based on WS2 nanotubes with high current-carrying capacity, Nano Lett., 13:3736–3741.
2. Tsverin Y, Popovitz-Biro R, Feldman Y, R. Tenne R, Komarneni M, Chakradhar Z, Sand A, Burghaus U, (2012) Synthesis and characterization of WS2 nanotube supported cobalt catalyst for hydrodesulfurization, Mater. Res. Bull., 47:1653–1660.
3. Zak A, Ecker L.S, Efrati R, Drangai L, Fleischer N, Tenne R, (2011) Large-scale Synthesis of WS2 Multiwall Nanotubes and their Dispersion, an Update, Sensors & Transducers, 12:1-3.
4. Yadgarov L, Choi C.L, Sedova A, Cohen A, Rosentsveig R, Bar-Elli O, Oron D, Dai H, Tenne R, (2014) Dependence of the absorption and optical surface plasmon scattering of MoS2 nanoparticles on aspect ratio, size, and media. ACS Nano, 8: pp. 3575–3583.
5. Yadgarov L, Rosentsveig R, Leitus G, Albu-Yaron A, Moshkovich A, Perfilyev V, Vasic R, Frenkel A.I, Enyashin A.N, Seifert G, Rapoport L, Tenne R, (2012) Controlled Doping of MS₂ (M=W, Mo) Nanotubes and Fullerene-like Nanoparticles, Angew. Chem. Int. Ed, 51: 1148 –1151.
6. Singh G, Chan H, Udayabhaskararao T, Gelman E, Peddis D,  Baskin A,  Leitus G,  Kr´al P, Klajn R, (2015) Magnetic field-induced self-assembly of iron oxide nanocubes, Faraday Discuss., 181: 403–421.

Biography:

Mihaela Albu is an expert in “Analytical high resolution transmission electron microscopy of alloys, steels, composites, porous materials and nanoparticles”. Her research interest includes “The understanding of fundamental effects induced by impurities in diverse alloys and nucleation of secondary phases in tempered and creep tested alloys and steels”.

Abstract:

Development of new materials for specific applications requires the fundamental understanding of the atomic scale effects which drives the micro- and nano-structure particularities. In order to understand, circumvent or exploit these effects advanced characterization methods for the whole range of nano-scaled precipitates are needed. This paper presents new developed and correlative microscopic methods for the investigation of different material types ranging from Mg and Al based alloys to chromium rich steels. Energy filtered transmission electron microscopy (EFTEM) and scanning TEM (STEM) provides insight into the material’s crystallography and chemistry quantitatively and at atomic resolution. STEM mode acquisition of 2 or 3D data sets of high angular annular dark field images (HAADF) at atomic resolution and both X-ray (EDX) and electron energy loss spectrometry (EELS) spectrum images proved to be very useful for the localization and identification of different modifying elements with very low concentration (Sr, Yb, Ag in Al-alloys and Ca in Mg-alloys). We observed that Sr atoms produce twinning only if they take interstitial positions in the eutectic Si. This effect is directly linked to the modification of the eutectic Si from a plate like to a fibrous morphology in Al-Si alloys. Yb on the other hand (in Al-Si alloys) cannot take such positions and thus they only form atomic chains inside the eutectic Si phase with no consequences on twinning. However, they segregate at the interface with matrix producing a refinement of the eutectic Si. In case of silver added to Al-Cu alloys, 2-5 atomic layers at the surface of the θ and precursors of Q phases have been found. Additionally, the nucleation and evolution of some precipitates in Cr steels during heat and creep treatment due to pipe- and substitutional diffusion could also be studied.

Recent Publications

1. Li JH., Albu M., Hofer F., Schumacher P., (2015) Solute adsorption and entrapment during eutectic Si growth in Al-Si-based alloys, Acta Mater. 83:187–202.
2. Albu M., et al (2016) Self-organized Sr leads to solid state twinning in nanoscaled eutectic Si phase, Scientific Reports 6:31635
3. Li JH., et al (2016) Effects of trace elements (Y and Ca) on the eutectic Ge in Al-Ge based alloys, Acta Mater. 111:85-95
4. Li JH., et al (2015) Correlative chatracterization of primary Al3(Sc,Zr) phase in an Al-Zn-Mg based alloy, Materials Characterization 102:62-70
5. Haberfelner G., Orthaker A., Albu M., Li JH., Kothleitner G., (2014) Nanoscale voxel spectroscopy by simultaneous EELS and EDX tomography, Nanoscale DOI:10.1039/c4nr04553j
6. This research has received funding from the FFG under project no. 839083 (COIN OPTIMATSTRUCT) and European Union within the 7th Framework Program [FP7/2007–2013] under grant agreement no. 312483 (ESTEEM 2).

Biography:

Thomas Emmerich has completed his MSc in Mechanical Engineering with specialization in Material Engineering in 2013. From 2013 to 2016, he completed his PhD in Liquid Metal Corrosion Group at Institute of Applied Materials-Applied Material Physics, Karlsruher Institute of Technology. During his PhD, he analyzed the material related aspects of the thermal decomposition of methane in liquid tin.

Abstract:

Statement of the Problem: The application of liquid tin as a process or as a heat transfer medium is limited, mainly due to its corrosive action on typical materials of construction like steels or nickel-based alloys. If the alloys are, however, protected against liquid tin, e.g., by surface layers, they may be employed as construction material.

Aim: The corrosion of liquid tin on austenitic steels and nickel-based alloys at high temperature is evaluated followed by first tests of possible protective surface layers.

Methodology: Corrosion experiments were performed on austenitic steels as well as nickel-based alloys. The alloys were exposed to liquid tin at 500, 700 and 1000°C for 25, 50 and 100 h. The occurring phenomena were analyzed and the associated material loss quantified. Candidate protective layer materials, e.g., carbides, nitrides or oxides, were formed on the alloys by thermochemical and thermophysical processes and their protection against liquid tin evaluated in screening tests at elevated temperatures.

Findings: Both alloy types exhibit selective leaching of nickel and formation of intermetallic compounds in the melt as well as layers on the corrosion scales. The material loss increases with exposure time as wells as testing temperature and is higher in case of the nickel-based alloys than for austenitic steels. In regard to the screening tests of potential protective surface layer materials, carbides and nitrides are stable against the liquid tin. A layer of chromium nitride significantly reduced the corrosion on a steel sample. In case of continuous oxide layers their stability and thus protection against liquid tin increases with layer thickness.

Conclusion: The results show the potential of surface layers to significantly reduce the corrosion of liquid tin. With further development, the layers reliability may be increased thus allowing to utilize liquid tin as a process medium.

Recent Publications

1. C. Schroer, V. Koch, O. Wedemeyer, A. Skrypnik, J. Konys, Silicon-containing ferritic/martensitic steel after exposure to oxygen-containing flowing lead–bismuth eutectic at 450 and 550 °C, Journal of Nuclear Materials 469 (2016) 162–176.
2. V. Tsisar, C. Schroer, O. Wedemeyer, A. Skrypnik, J. Konys, Long-term corrosion of austenitic steels in flowing LBE at 400 °C and 10–7 mass% dissolved oxygen in comparison with 450 and 550 °C, Journal of Nuclear Materials 468 (2016) 305–312.
3. M. Yurechko, C. Schroer, O. Wedemeyer, A. Skrypnik, J. Konys, Creep-rupture tests on chromium-containing conventional and ODS steels in oxygen controlled Pb and air at 650 °C, Nuclear Engineering and Design 280 (2014)686–696.
4. C. Schroer, O. Wedemeyer, J. Novotny, A. Skrypnik, J. Konys, Performance of 9% Cr steels in flowing lead–bismuth eutectic at 450 and 550 °C, and 10−6 mass% dissolved oxygen, Nuclear Engineering and Design 280 (2014) 661–672.
5. V. Tsisar, C. Schroer, O. Wedemeyer, A. Skrypnik, J. Konys, Corrosion behavior of austenitic steels 1.4970, 316L and 1.4571 in flowing LBE at 450 and 550 °C with 10–7 mass% dissolved oxygen, Journal of Nuclear Materials 454 (1–3) (2014), 332–342.

Biography:

Haider M Mohammad completed his PhD in Mechanical Engineering (Applied Mechanics and Failure of Materials) in Mechanical Engineering department at University of Basrah, College of Engineering. His research interests include “Failure of boilers, corrosion, fatigue, creep rupture, surface roughness, heat treatment, welding, optimization, sustainability, cold working and machining”.

Abstract:

The current study aims to find the optimum cutting parameters in turning process without using cutting fluids (dry cutting condition) towards sustainable manufacturing, where the power consumption and environmental pollution increases due to increase of the machining operations in manufacturing field. So, in order to save energy and environment and reduce cost, it is important to adopt sustainability in machining processes. The experimental work in this study involves the preparation of experiments on AISI 1045 carbon steel to collect the necessary data for implementing optimization process. The experiments were conducted by changing levels of cutting parameters (spindle speed, feed rate and cutting depth) in CNC turning machine. Surface roughness of the work piece has been depended as a quality indicator. Also the temperature of cutting tool has been recorded during machining the work pieces in order to control the temperature of cutting process. Theoretically, empirical equations for temperature of cutting tool and surface roughness of the work piece have been discovered. By using genetic algorithm technique, these equations have been used to find the optimum of cutting parameters spindle speed, feed rate and depth of cut. The optimum values obtained by genetic algorithm achieved sustainable cutting; spindle speed 588.96 rpm, depth of cut 0.50 mm and feed rate 64.55 mm/min in order to have the optimum of surface roughness in low cutting temperature.

Recent Publications

1. Elena G, Giacomo F (2014) What Is Sustainability? A Review of the Concept and Its Applications: Springer International Publishing Switzerland.
2. Janez K, Franci P (2009) Concepts Of Sustainable Machining Processes: 13th International Research/Expert Conference, Trends in the Development of Machinery and Associated Technology,  Hammamet, Tunisia, 16-21 October.
3. K.F,Man et al (1996) Genetic Algorithm: Concepts and Applications: IEEE Transactions on Industrial Electronics, Vol.43, No. 5, October.
4. M. Cemal Cakir, et al (2009) Mathematical Modeling of Surface Roughness for Evaluating the Effects of Cutting Parameters and Coating Material: journal of materials processing technology, Vol. 209.
5. Singiresu S. Rao (2009) Engineering Optimization, Fourth Edition, John Wiley & Sons, Inc,.
6. Young K, Choon M (2010) Surface Roughness and Cutting Force Prediction in MQL and Wet Turning Process of AISI 1045 Using Design of Experiments: Journal of Mechanical Science and Technology, Vol. 24.

Biography:

Zaid S Qassim has his expertise in Aluminum Casting Process and Mechanical Engineering. He completed his BSc in Mechanical Engineering at University of Basrah and pursuing his MSc at the same university. He is working as a Supervisor Engineer in the Oilfield at Chinese company- CPECC for maintenance and construction.

Abstract:

The improvement of the mechanical properties such as tensile strength, hardness and ductility is carried out in this paper by a new and developed technique in the additions field. ZnO nano rods are added to the molten of A356 aluminum casting alloys with specific weight percentages. The experimental work involves melting the scraps of cars wheels from aluminum casting alloys which are available locally inside the electrical furnace and adding the powder of ZnO nano rod manually to the graphite crucible that contain the molten of A356 and mixing the molten very well to make sure that the aluminothermic reaction between the ZnO nano rod and A356 occurred for whole molten, as a final step the molten is cast in the permanent mold and rapidly solidified by water. Tensile and micro hardness tests, microscopic and electron microscopic examinations are carried out to the obtained alloys. The results of the microscopic examinations showed that these additions acts as grain refiners after the quick solidification by making the microstructure of the modified A356 castings with ZnO nano rod have finer grains and more uniform distribution for the eutectic Si phases compared with the unmodified alloys. On the other hand, significant increase in mechanical properties such as tensile strength, elongation and hardness achieved. Furthermore, the optimal melting and holding temperature for this work is 700°C with holding time of 2 hours.

Recent Publications

Biography:

Ahmad K Jassim has expertise in “Sustainable manufacturing process, non-conventional forming process, waste management, production and engineering. He has three patents in the field of Refractory Materials. He completed his BSc in Production and Metallurgical Engineering at University of Technology in Baghdad; MSc in Global Production Engineering at Technical University Berlin (Germany); and PhD in Mechanical Engineering at University of Basrah.

Abstract:

In this paper, an empirical model is applied to predict the hardness, yield strength and tensile strength of rapid solidified ribbons. The discovered empirical equation is obtained depends upon the experimental results of rapid solidification process for 5083 Al-alloys. The empirical equations predict values and describe the behavior of ribbon with consideration of ribbon thickness, grain size, hardness, yield strength and tensile strength. The experimental work involves different operation conditions and the results indicate that orifice diameter, nozzle roll wheel gap and melting temperature have direct impact on the quality of alloy. Additionally, the results showed that there is a good agreement between experimental and predicted values where the correlation coefficient is 0.99. The experiment show that there is a possibility to produce very thin ribbons with thickness in micrometer by reducing the distance between nozzle and roll wheel, and reduce the orifice diameter of casting. The hardness and yield strength will be increased due to increasing the number of small grain size in the ribbons structure and rapidly heat transfer of the small ribbons thickness. Moreover, the optimal melting temperature of this alloy is 925ºC which produces high ribbon hardness compared with other melting temperature that used in this research.

Recent Publications

1. A. A. Bogno. A. Mairte, H. Henein, and Ch. A. Gandin (2014) Characterization of rapidly solidified metallic alloys using combination of experiments and modeling. COM 2014 Conference metallurgists' proceedings.
2. Ahmad K. Jassim, Ali S. Hammood (2014) Single roll melt spinning technique applied to produce micro thickness rapid solidified ribbons type 5083 Al-Mg alloy. International parallel conference on researches in industrial and applied science.
3. Ahmad K. Jassim, Ali S. Hammood (2014) Sustainable manufacturing process for bulk metallic glasses production using rapid solidification with melt spinning technique. International conference on material science and material engineering.
4. Ahmad K. Jassim, Ali S. Hammood (2014) Single roll melt spinning technique applied as a sustainable forming process to produce very thin ribbon 5052 and 5083 Al-Mg alloy directly from liquid state. Elsevier, Science direct, pp. 133-137.
5. B. Karpe et al., (2011) Modeling of heat transfers in the cooling wheel in the melt-spinning process. Journal of achievements in materials and manufacturing engineering. Volume 46, issue 1, International OCSO world press, PP. 88-94.

Biography:

Kausar Javed Khan has completed her PhD from Lahore College for Women University, Lahore, Pakistan. During PhD studies, she has prepared magnetic garnet series. She has done her MPhil in Solid State Physics from Centre of Excellence at Punjab University, Lahore, Pakistan. She currently holds the position of Assistant Professor at Gulberg College for Women, Lahore. She is also a Visiting Professor at FCC Chartered University, Lahore, Pakistan. She has also done Master’s in English Literature from University of Punjab, along with a Master’s in Educational Planning and Management.

Abstract:

YIG (yttrium iron garnet) is magnetic ferrite having chemical formula Y3Fe5O12 and high resistivity. Substituted YIGs have formula RexY3-x Fe5O12, where R represents rare earth elements. Polycrystalline cylindrical (13 mmx3.3 mm) six samples of holmium substituted YIG (HoxY3-xFe5 O12) were prepared by conventional ceramic technique. Powder samples were annealed  at 10000C (1 hour) and these were called green powders. The crystalline structure and dielectric properties of samples were studied by D8 Discover X-Ray diffractometer and Wayne Kerr impedance analyzer. Microstructural properties like crystallite size, dislocation density, micro-strain were calculated using XRD data. Increase in crystallite size was observed with the increase of holmium composition. Decreasing trend in dislocation density was observed with the increasing holmium contents. Dielectric parameters were studied with reference to changing holmium composition and changing frequency comprehensively. Both dielectric constant (∈) and dielectric loss (∈) decreased sharply with the increase of frequency at room temperature (300k).The decreasing trend in dielectric parameters was observed with the increase in holmium contents. This series of substituted YIG having small dielectric constant, low dielectric loss and negligible tangent loss can play the most vital role in many electronic devices in microwave region. Small dielectric parameters exhibited by these prepared magnetic garnets make them highly useful in telecommunication and defense industry.

Recent Publications

1. Anjum Qureshi, (2009) “Dielectric and magnetic properties of YIG/PMMA nano composites” Journal of Physics, Conference Series, 153 (2009) 012061.
2. Rased M.M., Hossien  M.M., Midany A.El, Ibrahim  I.A. (2009) “Effect of synthesis conditions on the preparation of YIG powders via co-precipitation method,” J.Magn. Magn. Magn. Mater.
3. Nimbore S.R., Shengule D.R., Shukla S.J., Bichile  G.K., Jadhav K.M., (2006) “Magnetic and Electrical Properties of Lanthanum substituted Yttrium Iron Garnets” J.Mater. Sci, Vol. 41, pp 6460-6464.
4. Huang C., Zhang Q. (2004) “Enhanced dielectric and Electrochemical responses in high dielectric constants of all polymer percolative composites,” Adv. Funet. Matter, Vol. 14, pp 501.
5. Sozeri H., Ghazanfar  N., ( 2009) “Another alternative to the Solid State Reaction method to synthesis nanocrystalline YIG, Ammonium Nitrate Melt technique,” J. Physics Conference, pp 153.

Biography:

Santhosh Mathesan is pursuing his PhD in Department of Applied Mechanics at Indian Institute of Technology Madras (IITM) at Chennai, India. Before joining IITM, he has completed his Master’s in Aeronautical Engineering at Madras Institute of Technology, Anna University in Chennai, India in the year 2012. His current research interests include “Materials like water responsive biopolymers/nanocomposites, which can potentially find application in bio-sensors and drug delivery”. He utilizes Molecular Dynamics Simulations to understand the atomistic level interaction mechanisms responsible for macroscopic properties observed in water responsive hydrogels. This helps in tailoring the properties of materials suitable for biomedical applications. He has also worked in design and fabrication of hybrid rocket motor. He has done thermal-mechanical characterization of hybrid fuel having high regression rate.

Abstract:

Moisture responsive biopolymers are gaining importance due to its capability to replicate the stimuli responsive behavior observed in nature. They are three dimensional polymer network structure which changes its volume, by retaining large quantity of water. They have wide range of applications in actuators, water purification and flow controlling valves. Self-folding is a well-known response observed in water responsive biopolymers. In the presence of water, the film experiences inhomogenous swelling maintaining it in differential stressed state. The differential stress state assists the film to exhibit self-folding phenomenon. Also, the water content in consecutive layers varies across thickness of the film. Thus, modifying the mechanical properties and diffusion characteristics of each layer of biopolymer film. Chitosan (CS) is a moisture responsive biopolymer which can demonstrate self-folding phenomenon. However, chitosan film shows structural instability during self-folding due to its lower mechanical properties and higher swelling capacity. Strength of biopolymers are either enhanced by cross-linking process or reinforcing with nanofillers. Here, chitosan matrix is reinforced with hydroxyapatite (HAP) to modify its mechanical properties. Though HAP enhances the strength of CSHAP film in dry state, diffusion of water alters its mechanical properties during the folding phenomenon. Therefore, it is necessary to understand the influence of water on mechanical properties of pristine CS and HAP reinforced chitosan. Molecular dynamics (MD) simulation is one of the promising tools to explore the mechanism behind macroscopic properties. In this work, we will present the influence of varying water content on directional dependent mechanical properties of CS and CSHAP nanocomposite systems. For these systems, the stiffness matrix will be determined by applying constant strain minimization technique in MD. It can be correlated with the direction dependent diffusion coefficient matrix explaining the self-folding process. Nano-mechanical characterization of CS and CSHAP in the dry and wet state will be performed using depth sensing nanoindentation. This technique will be complementing the results observed in MD simulation.

Recent Publications

1. Johnson B D, Beebe D J, Crone W C (2004) Effects of swelling on the mechanical properties of a pH-sensitive hydrogel for use in microfluidic devices Mater. Sci. Eng. C 24 575–581.
2. Fernandes R, Gracias D H (2012) Self-folding polymeric containers for encapsulation and delivery of drugs Adv. Drug Deliv. Rev. 64 1579–1589.
3. Franca E F, Freitas L C G, Lins R D (2011) Chitsosan molecular structure as a function of N-acetylation Biopolymers, 95 448-460.
4. Mathesan S, Rath A, Ghosh P (2015) Molecular mechanisms in deformation of cross-linked hydrogel nanocomposite Mater. Sci. Eng. C 59 157-167
5. Rath A, Mathesan S, Ghosh P (2015) Nanomechanical characterization and molecular mechanism study of nanoparticle reinforced and cross-linked chitosan biopolymer J. Mech. Behav. Biomed. Mater 55 42-52.