(SoE) School of Engineering

<p>Shiv Nadar University is a comprehensive, multidisciplinary, research-focused, and student-centric University offering a full range of academic programs at the undergraduate, postgraduate and doctoral level. With state-of-the-art infrastructure, the University comprises of academic wings, sophisticated labs, international standard sports facilities, amphitheaters, auditorium, conference rooms and smart classrooms. The University&rsquo;s goal is to become internationally recognized for the quality of its research and creative endeavors and their applicability to improving quality of life, generating new insights and expanding the boundaries of human knowledge creativity. Committed to excellence in teaching, research and service, the University aims to serve the higher education needs of India and the world beyond.</p>

Shiv Nadar University

A series of low band gap, planar conjugated polymers, P1 (PFDTBT), P2 (PFDTDFBT) and P3 (PFDTTBT), based on fluorene and benzothiadiazole, was synthesized. The effect of fluorine substitution and fused aromatic spacers on the optoelectronic and photovoltaic performance was studied. The polymer, derived from dithienylated benzothiodiazole and fluorene, P1, exhibited a highest occupied molecular orbital (HOMO) energy level at -5.48 eV. Density functional theory (DFT) studies as well as experimental measurements suggested that upon substitution of the acceptor with fluorine, both the HOMO and lowest unoccupied molecular orbital (LUMO) energy levels of the resulting polymer, P2, were lowered, leading to a higher open circuit voltage and short circuit current with an overall improvement of more than 110% for the photovoltaic devices. Moreover, a decrease in the torsion angle between the units was also observed for the fluorinated polymer P2 due to the enhanced electrostatic interaction between the fluorine substituents and sulfur atoms, leading to a high hole mobility. The use of a fused π-bridge in polymer P3 for the enhancement of the planarity as compared to the P1 backbone was also studied. This enhanced planarity led to the highest observed mobility among the reported three polymers as well as to an improvement in the device efficiency by more than 40% for P3. © 2017 Viswanathan et al.; licensee Beilstein-Institut.

World University root node

Electrical Engineering

Fulltext

Beilstein Journal of Organic Chemistry

Molecular-level architectural design using benzothiadiazole-based polymers for photovoltaic applications

The self-assembly and deposition mechanisms of nanoparticles in droplets on a substrate are significant in many inkjet printing-based industrial applications such as microelectronics, display systems, and paint manufacturing. In this study, we describe the underlying lack mechanisms of the self-assembly and deposition behavior of nanoparticles in inkjet-printed. We also demonstrate the development of flexible and photonic crystals structural color based on self-assembled silica photonic crystals. © 2017 IEEE.

Chemical Engineering

TRANSDUCERS 2017 - 19th International Conference on Solid-State Sensors, Actuators and Microsystems

Permanent encapsulation of nanoparticle patterns formed by inkjet printer for transparent and flexible anti-counterfeit applications

The linear stability of a bilayer fiber spinning process is analyzed for axisymmetric disturbances under isothermal conditions. The co-extruded fiber consists of two concentric layers of rheologically stratified polymeric fluids. While the core fluid is an entangled polymer melt described using the eXtended Pom-Pom (XPP) model, the sheath layer is a low molecular weight unentangled polymer modeled as an Upper Convected Maxwell (UCM) fluid. The analysis indicates that, for fast extensional flows, such an arrangement enhances the critical draw ratio of the process over that found from the spinning of XPP fluid alone, thus delaying the onset of draw resonance and stabilizing the system. Further, the range of flow Deborah number for stable spinning is found to be much broader than that for the UCM fluid alone. For low to moderately elastic flows, the stability behavior is governed mainly by the rheology of the more-elastic core layer (XPP fluid), whereas for the highly elastic flows, the stability behavior is dominated by the less-elastic sheath layer (UCM fluid). The sensitivity of the stability diagram with respect to various spinning flow parameters, like the relative fraction of core and sheath layers, the rheological stratification of two fluids, and the spine-line dimensions, has also been examined in order to identify the region of enhanced stability such that the draw resonance is suppressed. © 2017 Elsevier Ltd

Chemical Engineering Science

Stability analysis of bilayer polymer fiber spinning process

Activation energy and diffusion kinetics are important in modulating the high temperature oxidation behavior of metals. Recently developed multi-principal element alloys, also called high entropy alloys (HEAs), are promising candidate material for high temperature applications. However, the activation energies and diffusion kinetics of HEAs have been limitedly explored. We investigate the diffusional activation energy for oxidation of Al0.1CoCrFeNi HEA. Compared to conventional steels and Ni-based super alloys, the HEA showed a significantly higher diffusion activation energy. This behavior is explained based on low potential energy of the lattice and interstitial sites which effectively trap the atoms, limiting their diffusion. The atomic mean jump frequency for interstitial diffusion of oxygen in the HEA is four-orders of magnitude lower than T22 and T91 steels and seven-orders of magnitude lower compared to pure iron. Al0.1CoCrFeNi HEA showed the lowest oxidation rate compared to conventionally used steels, super-alloys, and coatings. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Mechanical Engineering

Advanced Engineering Materials

Activation Energy and High Temperature Oxidation Behavior of Multi-Principal Element Alloy

<p>A new analytical approximate expression for K distribution is proposed by expanding it in terms of orthogonal associated Laguerre polynomial. The expansion is truncated after first three terms, which yields a fairly close approximation to K distribution. The advantage of the proposed approximation is that the analytical closed form expression for bit error rate can be easily derived. KL measure is used to show the accuracy of the proposed approximation. The proposed approximate probability density function and bit error rate work well within the desired range of the channel parameter α, which is 1 &lt; α &lt; 2 and corresponds to the scintillation index value ranging from 2 to 3. We have also demonstrated the utility of our approximation for other quality of service metric such as fade probability. © 2009-2012 IEEE.</p>

Computer Science and Engineering

Physics

(SoNS) School of Natural Sciences

IEEE Photonics Journal

A novel approximation for K distribution: Closed-form BER using DPSK modulation in free-space optical communication

The conventional method of testing water quality is to gather samples of water manually and send to the lab to test and analyze. This method is time consuming, wastage of man power, and not economical. The water quality measuring system that we have implemented checks the quality of water in real time through various sensors (one for each parameter: pH, conductivity, temperature) to measure the quality of water. The ZigBee module in the system transfers data collected by the sensors to the microcontroller wirelessly, and a GSM module transfers wirelessly the data further from the microcontroller to the smart phone/PC. The system also has proximity sensors to alert the officials by sending a message to them via the GSM module in case someone tries to pollute the water body. This system can keep a strict check on the pollution of the water resources and be able to provide an environment for safe drinking water. © 2017 IEEE.

2017 International Conference on Computer, Communications and Electronics, COMPTELIX 2017

Real-time water quality monitoring system using Internet of Things

Erosion-corrosion is a critical problem in marine components and has huge economic impact. In the current study, friction stir processing was utilized for enhancing the erosion-corrosion resistance of SS316L steel, most widely used material for marine applications. Compared to the unprocessed alloy, the friction-stir processed specimen showed nearly 3.5 times and 5 times higher erosion and erosion-corrosion resistance respectively at oblique impingement. In contrast, erosion and erosion-corrosion resistance for processed alloy was 2 times higher at normal impingement. The unusual enhancement in erosion-corrosion resistance was attributed to surface strengthening through grain-size refinement and martensite phase formation. In addition, higher corrosion resistance due to stronger passivation also contributed towards superior performance of the processed alloy. © 2017 Elsevier B.V.

Wear

Enhancing the erosion-corrosion resistance of steel through friction stir processing

Photoconductive antennas (PCA) are becoming very popular sources for the generation of Terahertz (THz) radiation. Various studies have been reported in the literature to understand the different physics involved in the operation of PCA. However, the effect of the near fields on the radiated THz from PCA is not analyzed adequately. In this work, a theoretical calculation of the radiated near fields and their effect on the radiated fields from a large aperture PCA have been investigated. The carrier dynamics presented in this work include the effect of the near fields, interaction between electrons and holes and time-dependent development of polarization due to space charge. © 2017 IEEE.

2017 IEEE MTT-S International Conference on Numerical Electromagnetic and Multiphysics Modeling and Optimization for RF, Microwave, and Terahertz Applications, NEMO 2017

Effect of near fields on radiation from photoconductive antenna

Substrate-cell interactions for a bioimplant are driven by substrate's surface characteristics. In addition, the performance of an implant and resistance to degradation are primarily governed by its surface properties. A bioimplant typically degrades by wear and corrosion in the physiological environment, resulting in metallosis. Surface engineering strategies for limiting degradation of implants and enhancing their performance may reduce or eliminate the need for implant removal surgeries and the associated cost. In the current study, we tailored the surface properties of stainless steel using submerged friction stir processing (FSP), a severe plastic deformation technique. FSP resulted in significant microstructural refinement from 22 μm grain size for the as-received alloy to 0.8 μm grain size for the processed sample with increase in hardness by nearly 1.5 times. The wear and corrosion behavior of the processed alloy was evaluated in simulated body fluid. The processed sample demonstrated remarkable improvement in both wear and corrosion resistance, which is explained by surface strengthening and formation of a highly stable passive layer. The methylthiazol tetrazolium assay demonstrated that the processed sample is better in supporting cell attachment, proliferation with minimal toxicity, and hemolysis. The athrombogenic characteristic of the as-received and processed samples was evaluated by fibrinogen adsorption and platelet adhesion via the enzyme-linked immunosorbent assay and lactate dehydrogenase assay, respectively. The processed sample showed less platelet and fibrinogen adhesion compared with the as-received alloy, signifying its high thromboresistance. The current study suggests friction stir processing to be a versatile toolbox for enhancing the performance and reliability of currently used bioimplant materials. © 2017 American Chemical Society.

History

(SoHSS) School of Humanities and Social Sciences

Life Sciences

ACS Applied Materials and Interfaces

Friction Stir Processing of Stainless Steel for Ascertaining Its Superlative Performance in Bioimplant Applications

In this study, a novel substitution method for finding potential protein–protein interactions (PPIs) has been discussed. This newly designed method for analyzing PPI also aids in the comparison of evolutionary distances. The method deals with various data sets, and additionally performs measurable assessment to determine PPIs is introduced. PPIs are biologically relevant and aid in better conceptual framework of phylogenetic profiling. The newly designed framework gives vision to relate the topological properties of the system with evolutionary behavior of datasets. Firstly, this study found that the most conserved protein motifs exist at the roots of the system, whereas newer motifs with mutations have a tendency to dwell on the branches. In-depth functional analysis revealed that the most conserved motifs have high specificity for improved structural procedures and pathway engagements, which may help identify their formative parts in cells. In conclusion, this study demonstrates several important aspects for future studies focusing to enhance phylogenetic profiling systems. This study can also be used effectively to utilize such strategies to develop new biological insights which will further lead to understanding of disease mechanisms. © The Institution of Engineering and Technology 2017.