Day 3 :
- Materials Chemistry and synthesis
Location: Independence B
Drexel University, USA
Drexel University, USA
Time : 10:00-10:25
Hai-Feng Ji is currently professor in the Department of Chemistry at Drexel University. His research interests focus on micro/nano biosensors, MEMS devices, surface modification for sensors, and nanoassembly of organic molecules. He is currently a co-author of more than 120 peer-viewed journal articles and book chapters.
Phosphorene, a novel 2D material isolated from bulk black phosphorus, is an intrinsic p-type material with a variable bandgap for a variety of applications. However, these applications are limited by the inability to isolate large films of phosphorene. Here we present an in situ chemical vapor deposition type approach that demonstrates progress towards growth of large area 2D black phosphorus. Some other structures will be discussed as well.
Shanghai Ocean University, China
Time : 10:25-10:50
L W Zhang currently lectures at College of Information Science and Technology in Shanghai Ocean University. Her research areas are on theoretical development and application of numerical algorithms and computational methods for problems in mechanics, mathematics and bioscience. she has published over 50 SCI journal articles and her publications have been cited over 500 times. Her current h-index is 13 (ISI).
Traditionally, composites are reinforced by glass, carbon, basalt or aramid fibers; these reinforcement materials have been used for decades but the recent discovery of carbon nanotubes (CNTs) has led to a new type of CNT-reinforced composite being considered. Trailed by the concept of functionally graded materials (FGMs), the FG-CNT reinforced composite that has been proposed follows the functionally graded pattern of reinforcement, which is uniaxially aligned in the axial direction with its material properties graded in the thickness direction. In this study, the plate considered is of moderate thickness and, hence, the first-order shear deformation theory (FSDT) and Von Kármán assumption are adopted to incorporate the transverse shear strains, rotary inertia and moderate rotations. An improved moving least-squares (IMLS) approximation for the field variables is proposed for linear and geometrically nonlinear analysis of the studied plates. The modified Newton-Raphson method combined with the arc-length iterative algorithm is employed to solve the nonlinear deformation of the FG-CNT reinforced composite plates. Improvements in computational efficiency and elimination of shear and membrane locking are achieved using a stabilized conforming nodal integration scheme to evaluate the system’s bending stiffness. Through detailed parametric studies, CNT distribution, CNTs volume fraction, aspect ratio and thickness-to-width ratio and different boundary conditions are demonstrated to effect significantly on the mechanical behaviors of FG-CNT reinforced composite plates.
Turkish Air Force Academy, Turkey
Title: Effects of composition differences on the performance and properties of NiMnGa magnetic shape memory alloys
Time : 11:10-11:35
Gursev Pirge is Associate Professor of Mechanical Engineering, Department of Aerospace Engineering at the Turkish Air Force Academy, where he teaches courses in materials science and mechanical properties of materials. He has published peer-reviewed papers, and technical reports.
Magnetic shape memory alloys are promising candidates as sensor and actuator materials with high actuation frequency, energy density and strain. Magnetic shape memory effect allows even 50 times greater strains than in previous magnetically controlled materials (magnetostrictives). The large strains occur due to the magnetic field induced reorientation via twin boundary motion driven by mechanical stresses and/or magnetic fields. NiMnGa alloys, with their ability to develop large strokes under precise and rapid control, offer a great potential as magnetic shape memory materials. In addition to the magnetic shape memory phenomenon, NiMnGa alloys have shown conventional shape memory effect, traditional and magnetic-field-assisted superelasticity, magnetocaloric, and special transport properties. One of the major problems with the NiMnGa alloys is that even a slight change in the alloy’s composition causes significant changes in the martensitic transformation temperature. Magnetic shape memory effect is only possible in the martensitic region, so those shifts may result in a no-strain situation. Also, brittleness is a major obstacle for the applications of NiMnGa alloys. These two factors make it imperative to analyze the effect of composition on the transformation temperatures and investigate the microstructures of various alloys. In this study, effect of alloy composition and heat treatment on the microstructure, local composition, and thermal and dilatometric properties of Ni2MnGa alloys were investigated. The results of the characterization tests of various NiMnGa alloy crystals, with and without post-crystal growth heat treatment, were analyzed by differential scanning calorimetry, dilatometry, optical metallography and scanning electron microscopy. In addition, the study includes results about the effect of composition on the martensite transformation temperature. The results showed that as solidified, off-stoichiometric, alloys had three distinct microstructural features—a Heusler phase, a Mn-rich phase and a eutectic or eutectoid region. Various heat treatment procedures were applied to successfully remove the last phase. Heat treatment was also essential for the production of a distinct martensite transformation in differential scanning calorimetry and dilatometry traces and a magnetic shape memory effect. Composition variations from Bridgman growth were large enough that a shift in martensite start temperature might occur in some parts of the alloy, based on literature data for the dependence of martensite start temperature on composition.
University of Basra, Iraq
Title: Synthesis and thermal study of multi arms nano block copolymers via combination of ring opening polymerization and thio-click chemistry
Time : 11:35-11:50
Hadi Al-Lami is Professor of Polymer and Ceramic Chemistry, he is working as a Head of Chemical, Biological, Radiological Safety and Security Department at College of Science/University of Basra. In addition to that, he teaches courses in advance polymer chemistry, inorganic polymers, and biomaterial chemistry. He has published more than 80 peer-reviewed papers and 10 Iraqi Patents, and two books.
Many new well defined narrow molecular weight distribution polymers with multi-arms have been prepared by the Ring Opening Polymerization, using lactide with the compound resulted from the reaction of mercaptoethanol with poly octavinyl silsesquioxanes (POSS) by the thio-click chemistry. They were characterized by infrared spectroscopy (FTIR), Nuclear Magnetic Resonance (1HNMR and 13CNMR) and by Gel Permeation Chromatography (GPC), where all these analyses have proved the correctness of the expected structure and compositions. On the other hand images obtained from Scanning Electronic Microscopy (SEM) revealed the existence of nano-structures in the prepared copolymers due to the presence of the lactide array to give nanofiber within final compositions prepared. Thermal properties of prepared copolymers have been also studied. The results have demonstrated an increasing in their thermal stability with increasing chain length of lactide compound; also found that copolymers containing POSS in their composition gave higher thermal stability than those copolymers having no POSS.