(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

In this study, a C3-symmetric star-shaped discotic mesogen has been reported based on an electron-deficient tris(triazole) central rigid core functionalized with three peripheral trialkoxyphenyl units. The mesogen exhibits an enantiotropic columnar hexagonal (Colh) phase that can sustain over a significant temperature range. When used in space-charge limited current (SCLC) devices, it showed ambipolar charge transport behavior with high electron mobility (μe) of 1.61 × 10-2 cm2 V-1 s-1 at ambient temperature. The finding is sufficiently significant to warrant their use in organic electronic devices. © The Royal Society of Chemistry.

World University root node

Electrical Engineering

Journal of Materials Chemistry C

An electron-deficient tris(triazole)-based discotic liquid crystal that exhibits fast electron transport

Hydrogen (H)-bondedC3symmetrical discotic liquid crystals (DLCs) (Hpz-Cn-TP,n= 6, 8, 9) forming segregated columnar assembly are described. The columnar architectures are formed by electronically decoupled donor (D) (triphenylene) and acceptor (A) (heptazine) units linked through complementary H-bonding. Unlike triazine, tris(triazolyl)triazine and tris-benzimidazolyl benzene which have been explored in depth to form H-bonded DLCs, a new heptazine core has been explored, herein, for the first time to develop functional supramolecular materials of technological importance. AmongHpz-Cn-TPcomplexes, bothHpz-C8-TPandHpz-C9-TPshowed ambipolar charge transport with the former demonstrating a maximum hole mobility of 1.60 cm2V−1s−1and the latter showing a maximum electron mobility of 2.90 × 10−3cm2V−1s−1, measured through the space-charge limited current technique. Not only discrete conduction channels but also highly preorganized homeotropically aligned conduction pathways are observed in the reported complexes, resulting in efficient ambipolar charge transport. The adopted H-bonded synthetic approach does not only contribute to the electronic decoupling of D and A units but also offer an easy synthetic route to achieve DLC materials with high purity that have widespread use in commercial organic electronics. © The Royal Society of Chemistry 2021.

Enabling efficient ambipolar charge carrier mobility in a H-bonded heptazine-triphenylene system forming segregated donor-acceptor columnar assemblies

In the present paper, a refined trigonometric higher-order shear deformation theory has been presented with the conjunction of nonlocal theory for the vibrational response of functionally graded (FG) porous nanoplate. The displacement field is chosen based on assumptions that the out of the plane displacement consists of bending and shear components whereas the transverse shear-strain has nonlinear variation along the thickness direction. The number of unknown variables is four, as against five in other renowned shear deformation theories. The governing equations have been derived using Hamilton's principle. A generalized porosity model has also been developed to accommodate both even and uneven type of distribution of porosity in the FG nanoplates. The closed-form solution of simply-supported FG porous nanoplates is obtained and the results are compared with the available reported results. In finite element solution, a C0 continuous isoparametric quadrilateral element has been used with various conventional and unconventional boundary conditions. The effects of various parameters like small-scale effect, aspect ratio, volume fraction index, porosity volume fraction, and thickness ratio have been investigated. The significant influence of small-scale effects and porosity inclusions have been observed in the reported results. It has been reported that both closed-form and finite element solutions with the present theory can make accurate predictions of the free vibration response. © 2021 Techno-Press, Ltd. All Rights Reserved.

Mechanical Engineering

Advances in Nano Research

Size-dependent vibration response of porous graded nanostructure with FEM and nonlocal continuum model

In the present work, environment friendly non-fluorinated superhydrophobic composite coatings were developed using naturally available carnauba wax from palm tree, Copernicia prunifera. The hierarchically structured coating morphologies were composed of micro-scale protrusions along with submicroscopic pores (non-composite) and protrusion (composite). The hierarchically structured carnauba wax coatings showed extreme de-wetting with superhydrophobicity (θ > 150°) and low hysteresis (<5°). In contrast, the other mineral and animal waxes showed mild hydrophobic behavior with high hysteresis (>10°) owing to flat morphology. These peculiarities in morphology and hence de-wetting properties are related with the viscosity differences. Further, the composite wax coating also showed high resilience to simulated rain and weathering due to high roughness and mechanical strength. The composite wax showed high ultimate strength (14 MPa) and elastic modulus (427 MPa) than the non-reinforced wax (8.8 MPa and 97 MPa, respectively). The results showed that composite carnauba wax coatings provide an effective and environment friendly solution for developing superhydrophobic self-cleaning surfaces. © 2021 Elsevier B.V.

Industrial Crops and Products

Development of natural wax based durable superhydrophobic coatings

CD4-mimetic HIV-1 entry inhibitors are small sized molecules which imitate similar conformational flexibility, in gp120, to the CD4 receptor. However, the mechanism of the conformational flexibility instigated by these small sized inhibitors is little known. Likewise, the effect of the antibody on the function of these inhibitors is also less studied. In this study, we present a thorough inspection of the mechanism of the conformational flexibility induced by a CD4-mimetic inhibitor, NBD-557, using Molecular Dynamics Simulations and free energy calculations. Our result shows the functional importance of Asn425 in substrate induced conformational dynamics in gp120. The MD simulations of Asn425Gly mutant provide a less dynamic gp120 in the presence of NBD-557 without incapacitating the binding enthalpy of NBD-557. The MD simulations of complexes with the antibody clearly show the enhanced affinity of NBD-557 due to the presence of the antibody, which is in good agreement with experimental Isothermal Titration Calorimetry results (Biochemistry2006, 45, 10973-10980).

Chemical Engineering

Chemistry

(SoNS) School of Natural Sciences

Fulltext

Molecules (Basel, Switzerland)

Does Antibody Stabilize the Ligand Binding in GP120 of HIV-1 Envelope Protein? Evidence from MD Simulation

Improper waste disposal has resulted in rapid deterioration of the environment and the advent of fatal diseases. Carcinogenic substances that percolate into the ground deteriorate the quality of groundwater and soil. Moreover, pollution from large-scale burning of agricultural waste each time after the harvest season makes the goal of a healthy environment of utmost importance. Toxins, such as polycyclic aromatic hydrocarbons (PAH) and heavy metal contaminants, have several pathways to enter into the environment and bio-accumulate within living organisms. The objective of this study is to synthesise a substance that will break the source-receptor pathway resulting in cleaner water and soil. Biochar, through ion exchange or physical adsorption, has the capacity to adsorb heavy metal ions such as those of cadmium. The biochar was synthesised from biomass consisting of wheat straw, rice husk and bagasse. The biomass was then heated to temperatures ranging from 300 to 700 °C using the process of slow pyrolysis, in an environment in which the oxygen supply was limited. The samples were then subjected to Fourier transform infrared spectroscopy (FTIR) to ascertain the functional groups present followed by powder X-ray diffraction (XRD) to determine the elements or form of metal oxides present in the samples. The samples were mixed with a known amount of cadmium solution, and the final testing was performed using atomic absorption spectroscopy (AAS). The final testing directly showed the heavy metal ion adsorption efficiencies of biochar derived from different types of biomass, giving an insight into the future scope of using biochar has a remediating agent © 2021, Springer Nature Singapore Pte Ltd.

Civil Engineering

Lecture Notes in Civil Engineering

Remediation of Cadmium-Contaminated Soil Using Biochar Derived from Wheat Straw, Rice Husk and Bagasse

We report experimental evidence of circulation reversal in evaporating drops. The internal flow patterns and particle distribution inside the evaporating water droplet with suspended polystyrene particles was studied using the Particle Image Velocimetry (PIV) technique. Droplet placed on externally heated substrate showed two symmetric and counter rotating Marangoni convection cells at the beginning of evaporation process. Towards the final stages of evaporation, the two counter rotating Marangoni convection cells reversed the direction of circulation. Interestingly, it was observed that between these two stages four symmetric and counter rotating convection cells appeared inside the evaporating droplet. Our results are in support of recent theoretical investigations on circulation reversal in evaporating drops. The flow patterns were driven by the surface tension gradient caused by the surface temperature distribution along the droplet-air interface. The surface temperature distribution is not only dependent on the non-uniform evaporation flux but also on the conduction path from the substrate to the droplet surface. Towards the end of evaporation, the fluid flow becomes radially outward from the center to the pinned edge of the droplet. We have also investigated the evaporating droplets placed on a curved substrate. Unlike the case of flat substrate, the evaporation from curved surface resulted monotonic temperature profile. The particle distribution and resulting deposition patterns was strongly influenced by the internal fluid flow pattern and was observed to be different from that of a flat substrate. © 2021, The Author(s), under exclusive licence to Springer Nature B.V. part of Springer Nature.

Microgravity Science and Technology

Analysis of Circulation Reversal and Particle Transport in Evaporating Drops

Group maintenance deals with performing preventive maintenance (PM) on other components when the system stops due to induced failure or scheduled PM interval of a particular component. Group maintenance actions save downtime costs and other production losses. However, simultaneous maintenance of all units is not always economically beneficial. As a consequence, the decision to which group of components is maintained is very selective due to economic and stochastic interdependencies. In the present paper, we propose a novel and efficient group maintenance model in the multi-unit series system for grouping under PM intervals. The objective is to obtain an optimum group of components and PM intervals which minimizes the expected total maintenance cost of the system per unit time. A recently developed meta-heuristic named teaching–learning-based optimization (TLBO) algorithm is applied to optimize the objective function. The peculiarity of TLBO is that unlike other evolutionary-based heuristics it is a parameterless algorithm which makes it computationally easy to understand and implement. Computational results yield the effectiveness of the proposed approach when compared with traditional maintenance practices. © 2021, Springer Nature Singapore Pte Ltd.

Lecture Notes in Mechanical Engineering

Group Preventive Maintenance Model for Multi-unit Series System: A TLBO Algorithm-Based Approach

Fraudulent Resource Consumption (FRC) attacks can be synthesized by subtly consuming metered resources of the cloud servers over a sustained period of time. The objective of the attacker in such attacks is to exploit the utility pricing model by fraudulently consuming cloud resources. This skillful over-consumption of resources results in a considerable financial burden to the client. These attacks are characterized by low-intensity HTTP requests per hour, akin to requests by legitimate users. Hence, the attack requests differ in intent but not in content, which makes FRC attacks hard to detect. In this paper, we propose P-estimation detection scheme to effectively detect these attacks. This is accomplished by training several deep learning LSTM models based on the web server logs. An estimate of attack percentage is calculated and then used to deploy the appropriate detection model. This technique takes into account the dynamic nature of websites where the popularity of web pages can change with time, by retraining and updating the detection models periodically. To the best of the authors’ knowledge, this technique outperforms all the existing FRC detection techniques with a False Negative Rate (FNR) and False Positive Rate (FPR) of 0.0059\% and 0.0\% respectively. The proposed technique is able to detect attacks as low as 2\% intensity. In addition to the detection scheme, this paper also delivers a mitigation and attribution technique to identify such attackers and block them. © 2020 Elsevier Ltd

Computer Science and Engineering

Journal of Information Security and Applications

Detection and mitigation of fraudulent resource consumption attacks in cloud using deep learning approach

Owing to their rapid charge-discharge, extremely low maintenance, high power density, versatile operating temperatures and durability, supercapacitors are widely used as electrochemical storage devices in advanced energy applications. In recent years, transition metal oxides, especially nano-textured CuO structures have gained much attention as a low cost and widely available electrode material for supercapacitors. However, the existing techniques for developing nano-textured CuO involve a large number of processing steps through multiple chemical treatments. Further, the performance of nano-structured copper oxides needs to be significantly enhanced to make them commercially viable. Here, we report a facile, two step approach comprising surface activation through thermomechanical treatment and electrochemical dealloying of a Cu-Zn alloy for developing a 3-dimensional hierarchical CuO microstructure. Surface activation prior to dealloying significantly accelerates the reaction kinetics and the hierarchical microstructure comprising micro and nano-scale porosity develops in a few seconds only. Electrochemical studies revealed that the surface activated electrode possesses a high areal capacitance of 1.68 F cm−2at a current density of 5 mA cm−2, exhibits an excellent cycling stability with 90% retention for 5000 cycles at a current density of 15 mA cm−2and a high energy density of 0.33 mW h cm−2. The reported specific capacitance is one of the highest values obtained for copper-based alloys which is attributed to its unique 3D hierarchical microstructure that favours rapid ion intercalation and the increased surface area for energy storage. Electrochemical analysis indicates intercalation pseudo-capacitance as the primary charge storage mechanism. The current approach is highly generic and can be applied for a wide number of material systems which signifies its huge potential in the emerging field of advanced supercapacitors, and portable and flexible electronics. © The Royal Society of Chemistry 2021.