Department of Metallurgical & Materials Engineering

&ldquo;IIT Jodhpur is committed to impart quality education to facilitate the creation of qualified, competent and responsible human resources to meet the emerging technological challenges of the world. It is working towards creating an equitable learning platform that is positive, accessible and effective in the face of the modern societal and scientific advancements.

Flexibility in curriculum, in all its academic programs, encompassing elements of teaching, research, creativity, innovation and entrepreneurship is the most unique feature of IIT Jodhpur. The Department of Science and Technology (DST), under the National Mission on Cyber Physical Systems, has identified IIT Jodhpur as a Technology &amp; Innovation Hub in the area of Augmented Reality and Virtual Reality. The institute has also been nominated as the coordinator for the Jodhpur City and Knowledge Cluster by the Office of Principal Scientific Adviser, Government of India.

The sprawling 852-acre IIT Jodhpur campus is a majestic tribute to the deep-rooted diverse cultural heritage of the region. The campus is an architectural masterpiece, which is slated to become an international exemplar of sustainability with net-zero energy, and advanced water and waste management strategies.&rdquo;

IIT Jodhpur

Mesoscale simulations based on the resolved shear stress (RSS) analysis and the crystal plasticity finite element method (CPFEM) simulations were used to elucidate the deformation behaviors of E-form and AZ31 magnesium (Mg) alloys and the evolution of tension twin (TTW) and compression twin (CTW) variants during mini-V-bending. RSS analysis, which is based on the Schmid tensor, was used to calculate the type of twin variants and the number of TTW and CTW variants that evolved in the deformed Mg alloys. However, RSS analysis considers neither the critical resolved shear stress (CRSS) of twin systems nor the interaction with neighboring grains, and it failed to accurately predict the twin behaviors of deformed grains. This study simulated the spatial distributions of the relative activities of different deformation modes, accumulated twin fractions, accumulated plastic strains, and effective stresses via CPFEM. Compared with the RSS analysis, CPFEM simulation precisely explained the twin behaviors observed in both E-form and AZ31 Mg alloys. © 2018, The Korean Institute of Metals and Materials.

World University root node

Metals and Materials International

Mesoscale Simulation of Deformation Behaviors of E-form and AZ31 Mg Alloys During Ex-Situ Mini-V-Bending Tests

The Janus structures of transition metal dichalcogenides with intrinsic dipoles have recently drawn attention as efficient candidates in the class of non-precious metal photocatalysts for water splitting. Here, we have proposed Janus ScXY (X/Y = S, Se, or Te, X ≠ Y) monolayers as promising catalysts for the hydrogen evolution reaction (HER). We have thoroughly investigated the structural stabilities of the ScXY monolayers, as a primary step to understand the splitting mechanism more accurately. It has been observed that Janus ScSSe and ScSeTe monolayers are dynamically, thermally and mechanically stable, whereas the ScSTe monolayer is dynamically unstable. Moreover, based on hybrid functional (HSE06) calculations, these stable ScSSe and ScSeTe monolayers are semiconductors with direct band gaps of 1.810 and 0.921 eV, respectively. Considering spin-orbit coupling on top of the HSE06 calculations results in an insignificant change in the band gaps. The steady optical responses of Janus ScSSe and ScSeTe, respectively, in the visible and near IR spectra demonstrate their photocatalytic activities in the respective regions. Interestingly, we have observed excellent performance shown by the ScSeTe monolayer, where both surfaces are catalytically active, and maintain close to thermoneutral conditions with near-zero adsorption free energy at different H∗ coverages. Comparatively, the ScSSe monolayer shows poor performance for the HER due to strong bonds with the adsorbed hydrogen. Also, it has been confirmed that even the application of ±2% strain on the ScSSe monolayer does not enhance its HER activity. Our theoretical predictions demonstrate that out of all the Janus ScXY monolayers studied here, ScSeTe is the most active catalyst for the HER to efficiently split water, which certainly could make it worth performing further experimental investigations. This journal is © The Royal Society of Chemistry.

Catalysis Science \& Technology

Probing the active sites of newly predicted stable Janus scandium dichalcogenides for photocatalytic water-splitting

The selection of a suitable two dimensional anode material is one of the key steps in the development of alkali metal ion batteries to achieve superior performance with an ultrahigh rate of charging/discharging capability. Here, we have used state of the art density functional theory (DFT) to explore the feasibility of two dimensional (2D) honeycomb boron arsenide (h-BAs) as a potential anode for alkali-metal (Li/Na/K)-ion batteries. The structural and dynamic stability has been confirmed from the formation energy and the non-negative phonon frequency. The h-BAs monolayer exhibits negative adsorption-energy values of -0.422, -0.321 and -0.814 eV, for the Li, Na, and K-ions, respectively. Subsequently, during the charging process the adsorption-energy increases considerably without an energy-barrier when any of the A-atoms achieve a crucial distance (∼8 Å). In addition, it has been observed that insertion of the mono alkali metal atom into the h-BAs surface results in the semi-conducting nature of the monolayer being transformed into a metallic-state. The low energy barriers for Li (0.522 eV), Na (0.248), and K (0.204 eV) active ion migration imply high diffusion over the h-BAs surface, hence suggesting it has a high charge/discharge capability. Moreover, we have obtained low average operating voltages of 0.49 V (Li), 0.35 V (Na) and 0.26 V (K) and high theoretical capacities of 522.08 mA h g-1 (for Li and Na) and 209.46 mA h g-1 (for K) in this study. The aforementioned findings indicate that a h-BAs monolayer could be a promising anode material in the search for low cost and high performance alkali metal ion batteries. © the Owner Societies 2019.

Physical Chemistry Chemical Physics

Ab initio study of a 2D h-BAs monolayer: a promising anode material for alkali-metal ion batteries

In the class of two-dimensional (2D) materials, group III2-VI3 compounds have drawn intense attention due to its excellent surface properties. In this work, based on first-principles calculations, we have systematically investigated the structural, electronic, optical and photocatalytic properties of a ZnTe/In2Te3 heterostructure, along with its interfacial effects, to design an efficient photocatalyst. We have employed hydrogen adsorption free energy (ΔGH∗) as a key parameter to demonstrate the enhancement in photocatalytic activity of ZnTe/In2Te3 compared to a pristine In2Te3 monolayer, which is further verified with the explicit water environment. The underlying mechanism is governed by the partial charge distributions of pristine In2Te3 and ZnTe/In2Te3 heterostructures. The presence of the ZnTe monolayer also altered the bandgap of the In2Te3 monolayer from an indirect gap of 1.238 eV to direct gaps of 0.298 eV and 0.181 eV in A- and B-type interfaces of the ZnTe/In2Te3 heterostructure, respectively. Calculated optical absorption spectra indicate that ZnTe/In2Te3 heterostructures possess better sunlight-harvesting capability compared to monolayer In2Te3 near the infrared and visible light regions, implying their potential as an excellent light-absorber. Our predictions provide new guidance for designing 2D III2-VI3 heterostructures and expand the applications of these materials in photovoltaics, photocatalysts, and other nanodevices in the future. This journal is © The Royal Society of Chemistry.

Journal of Materials Chemistry A

Interfacial aspect of ZnTe/In 2 Te 3 heterostructures as an efficient catalyst for the hydrogen evolution reaction

The effect of intrinsic point defects on relaxor properties of 0.68 PbMg1/3Nb2/3O3-0.32 PbTiO3 thin films is studied across nearly 2 orders of magnitude of defect concentration via ex post facto ion bombardment. A weakening of the relaxor character is observed with increasing concentration of bombardment-induced point defects, which is hypothesized to be related to strong interactions between defect dipoles and the polarization. Although more defects and structural disorder are introduced in the system as a result of ion bombardment, the special type of defects that are likely to form in these polar materials (i.e., defect dipoles) can stabilize the direction of polarization against thermal fluctuations, and in turn, weaken relaxor behavior. © 2019 American Physical Society.

Fulltext

Physical Review Letters

Defect-Induced (Dis)Order in Relaxor Ferroelectric Thin Films

There is growing interest in the study of thin-film pyroelectric materials because of their potential for high performance thermal-energy conversion, thermal sensing, and beyond. Electrothermal susceptibilities, such as pyroelectricity, are known to be enhanced in proximity to polar instabilities, and this is conventionally accomplished by positioning the material close to a temperature-driven ferroelectric-to-paraelectric phase transition. The high Curie temperature (TC) for many ferroelectrics, however, limits the utility of these materials at room-temperature. Here, the nature of pyroelectric response in thin films of the widely studied multiferroic Bi1-xLaxFeO3 (x = 0-0.45) is probed. While BiFeO3 itself has a high TC, lanthanum substitution results in a chemically induced lowering of the ferroelectric-to-paraelectric and structural-phase transition. The effect of isovalent lanthanum substitution on the structural, dielectric, ferroelectric, and pyroelectric response is investigated using reciprocal-space-mapping studies; field-, frequency-, and temperature-dependent electrical measurements; and phase-sensitive pyroelectric measurements, respectively. While BiFeO3 itself has a rather small pyroelectric coefficient at room temperature (∼-40 μC/m2 K), 15% lanthanum substitution results in an enhancement of the pyroelectric coefficient by 100% which is found to arise from a systematic lowering of TC © 2019 Author(s).

APL Materials

Enhanced pyroelectric properties of Bi1-xLaxFeO3 thin films

Deterministic creation of multiple ferroelectric states with intermediate values of polarization remains challenging due to the inherent bi-stability of ferroelectric switching. Here we show the ability to select any desired intermediate polarization value via control of the switching pathway in (111)-oriented PbZr 0.2 Ti 0.8 O 3 films. Such switching phenomena are driven by kinetic control of the volume fraction of two geometrically different domain structures which are generated by two distinct switching pathways: one direct, bipolar-like switching and another multi-step switching process with the formation of a thermodynamically-stable intermediate twinning structure. Such control of switching pathways is enabled by the competition between elastic and electrostatic energies which favors different types of ferroelastic switching that can occur. Overall, our work demonstrates an alternative approach that transcends the inherent bi-stability of ferroelectrics to create non-volatile, deterministic, and repeatedly obtainable multi-state polarization without compromising other important properties, and holds promise for non-volatile multi-state functional applications. © 2019, The Author(s).

Nature Communications

Kinetic control of tunable multi-state switching in ferroelectric thin films

This work figures the conceptual background of impedimetric measurements. Impedance measurement is a convenient approach for exploring the change in electrical behavior of diverse materials. An overview of in practice impedance analysis on CHI660D electrochemical work station is presented. Detection of microorganism causing foodborne diseases using IDE and other methods, toxic metal ion quantification, environment pollutant monitoring are described applications in this work. This work also reviewed the noticeable development in impedance measurement devices based on AD5933 such as bio-impedance measurement and explosive material detection. Biological signals are detected by transducing them into electrical analogy, detection of which is not a big issue. The main challenges are to convert biological signal into electrical information. Electrochemical sensors present captivating techniques to determine the content of sample under test. Electrochemical sensing platforms come up with an appealing methodology to interpret the concentration of biological sample as these sensors directly translate biological information to an electronic one. Huge amount of sensing platforms and corresponding devices has been developed. EIS is a rapid and easily computerized technique used to characterize biomolecules, inorganic materials, having a wide range of applications. The measured impedance spectra are generally fitted to an analogous electrical circuit model which constitutes an electrical documentation of the SUT by disclosing its behavior and properties. Quick, highly selective/specific and sensitive techniques to quantify biological and biochemical molecules and other target species are of great importance in biomedical and biotechnological application. Recent developments trends for handy, portable, fast and precise impedance analyzer is discussed. AD5933 evolution kit is reviewed. ©BEIESP.

International Journal of Innovative Technology and Exploring Engineering

Impedimetric sensors: Principles, applications and recent trends

The present work discusses the evolution of grain boundary structure during thermomechanical processing and its effect on sensitization behavior in a nickel-based superalloy. Alloy 600 was deformed to varied degrees of strain (4–25%) using hot rolling followed by annealing at 1000 °C for 10 min followed by water quenching. Structure of the grain boundary was analyzed with reference to various parameters, such as grain boundary character distribution, twin-related domains, misorientation, and triple junction distribution. Each thermomechanically processed sample was heat-treated at 650 °C for 24 h before studying its sensitization behavior. The effect of structure of the grain boundary on sensitization was assessed through double loop electrochemical potentiokinetic reactivation test and measured in terms of degree of sensitization (DOS). DOS was found to be in a direct relation with the fraction of random high-angle grain boundaries and their connectivity, while it was inversely related to the fraction of low-Σ coincidence site lattice boundaries and special triple junctions. Residual strain and the fraction of low-angle grain boundaries were found to be weakly related to DOS. We show that a simple parameter can be used to predict the combined effect of all these factors on sensitization behavior. © 2018, Springer Science+Business Media, LLC, part of Springer Nature.

Journal of Materials Science

The effect of grain boundary structure on sensitization behavior in a nickel-based superalloy

Perchlorate is a highly toxic compound. It has both chemical and physical properties. Perchlorate is not easily degradable compound by both bio and non-bio degradation process because of its high stability, highly water soluble compound and low absorption. That’s why perchlorate reduction becomes a big challenge. In this research work we studied different type of electrochemical technique and effect of different electrodes on these techniques. In present days, many techniques were developed for the detection or reduction of perchlorate such as bio-degradation, optical, chemical, electrochemical and microbial technique. This article gives information about application of electrochemical technique for the detection or reduction of perchlorate. The electrochemical techniques have various types for the detection of ion. These techniques grouped on the behalf of various types of electrical signal such as potential or voltage, current and impedance which were produce in the presence of perchlorate into aqueous solution. Electrochemical technique such as impedance spectroscopy, this technique was performed on the electrochemical work station by applied a constant range of frequency. In cyclic voltammetry technique we were given a constant potential range and found results in the form of oxidation and reduction current. In the reduction of perchlorate history various researcher was found results using different electrochemical technique on different types of electrodes. The perchlorate salts and perchlorate have some useful application in the defense field, batteries, automobile airbags, rocket propellants and fuels. Perchlorate contamination is become a worldwide health problems. In many western states perchlorate was found in ground and surface water. It disturbs the thyroid gland to uptake iodine the human body. So its prevention technique was needed. However, the electrochemical techniques have more advantage such as low cost, user friendly, label free and real time monitoring over all other techniques. So we focus on electrochemical detection technique for the perchlorate. © BEIESP.