(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

There is significant demand for molecular functional materials with tailored light-emissive and charge transport properties for their utilization in organic optoelectronic devices. Motivated by such promising properties, we present the synthetic design and emissive and semiconducting properties of aggregation-induced emission (AIE)-active columnar discotic liquid crystals based on cyanostilbene-modified benzenetricarboxamide derivatives (1a, 1b, and 1c). Enantiotropic mesomorphic behavior over a wide temperature range, including room temperature, with columnar hexagonal self-assembly was observed for all of the compounds. The space-charge limited current (SCLC) technique revealed the ambipolar charge transport for reported materials with balanced electron and hole transport of the order of 10-3cm2/(V s). On the other hand, all of the compounds 1a-c were tested as emitter materials in solution-processed organic light-emitting devices at different concentrations with several hosts, viz., poly(vinylcarbazole) (PVK), 1,3-bis(N-carbazolyl)benzene (mCP), bis[3,5-di(9H-carbazol-9-yl)phenyl]diphenylsilane (SimCP2), and (carbazolyl)-1,10-biphenyl (CBP). The maximum luminance of 1255 cd/m2corresponding to sky-blue emission was observed for compound 1a at 3.0 wt % with the CBP host. © 2022 by the authors.

World University root node

Electrical Engineering

ACS Applied Electronic Materials

Electroluminescent Aggregation-Induced Emission-Active Discotic Liquid Crystals Based on Alkoxy Cyanostilbene-Functionalized Benzenetricarboxamide with Ambipolar Charge Transport

Wireless channel characteristics are random in nature. Consideration of shadowing and fading effect in the channel is necessary so as to capture the behavior of signal variation at the receiving end. The composite effect of the phenomenon is prominent in applications where receiving nodes are deployed in deep faded region with shadowed signal propagation. This becomes more important as the average power of the signal becomes random due to fading and shadowing effects. This effect is more prominent to capture the random behavior of the channel one has to adopt the probabilistic framework by using probability distributions. The Rayleigh–lognormal distribution (RLD), useful in characterizing fading and shadowing aspects of wireless communication channel, has a complex integral having no closed form. Noting that inverse Gaussian distribution closely approximates lognormal distribution, a better approximation is proposed by generalized inverse Gaussian distribution (GIGD). While different combination of compound probability distribution is capable of capturing the behavior of the channel, no such compound distributions work for the complete range of channel variations. Thus, the probability density function of the resulting Rayleigh–generalized inverse Gaussian distribution (RGIGD), besides having a closed form and being analytically tractable, is a more appropriate substitute for RLD. Based on Kullback–Leibler (K–L) measure to assess closeness of two probability distributions, it is found that the proposed RGIGD distribution is closer to the original RLD than other distributions, viz. RGD, RIGD. Further, the proposed distribution can be considered to provide a solution for a large range variation in the sense that RGD and RIGD become its special cases and yields more realistic values of quality of service parameters along with flexibility of covering a wide range of the signal variations through its special cases. © 2021, Shiraz University.

Computer Science and Engineering

Iranian Journal of Science and Technology - Transactions of Electrical Engineering

Composite Channel Model for Wireless Propagation with Wide-Range Signal Variation Using Rayleigh–Generalized Inverse Gaussian Distribution

Castor oil (CO) and cocoa butter (CB) were studied as potential hydrophobic and plasticizer additives for pectin biopolymer films. The optimum concentration of CO and CB additives and drying temperature were determined by using a 23 (two-level, three-factor) statistical factorial design of experiments. The CO and CB integrated pectin films displayed remarkably lower moisture and oxygen transmission rates relative to the control pectin films. Furthermore, the hydrophobicity, ductility (elongation at break) and flexibility (low elastic modulus) of the CO and CB added films are significantly higher than that of the control pectin films. The modified films retained 90% of their weight at a temperature of 200 °C, indicating their excellent thermal stability. A very low glass transition temperature of 2 ± 2 °C and a melting point of ~ 150 °C of the films designates their stability under processing and storage conditions. Scanning electron microscopy analysis confirmed the formation of homogeneous films without any micro-cracks or agglomerations. Detailed statistical analysis shows that the optimal conditions for producing improved pectin films: the concentration of CO (15% w/w of pectin) and CB (10% w/w of pectin) and film drying temperature (T = 35–52 °C). A coating of film forming solution comprising optimum amounts of pectin, CO and CB was able to delay the ripening of a banana by 4 days and of capsicum by 15 days at atmospheric conditions. © 2022, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.

Physics

(SoNS) School of Natural Sciences

Mechanical Engineering

Journal of Polymers and the Environment

Castor Oil and Cocoa Butter to Improve the Moisture Barrier and Tensile Properties of Pectin Films

In this paper, we propose an idea of asymmetric bending in a fiber reinforced soft pneumatic actuator. The mixing of two intrinsically different elastomers Ecoflex 00-20 (Smooth-On, Macungie, PA, USA) and Dragon Skin 00-20 (Smooth-On, Macungie, PA, USA) with viscosities 3,000 cps and 20,000 cps respectively in various proportions and curing them all together has resulted in expected results. This can be extremely useful for how we look and manufacture soft actuators. This is going to help in cutting our costs significantly and improving the pneumatic loading strength on a greater scale. All of this, with an increased amount of precision and controllability. Experiments were carried out to determine the effects of various proportions of two different elastomers and we have also renewed the curing procedure. Our methodology can be used to design a soft actuator that bends asymmetrically without external restrictions. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.

Lecture Notes in Networks and Systems

GradNet: A Viscosity Gradient Approach to Achieve Dexterity in Soft Pneumatic Actuators

In the present article, an exact solution has been given to investigate the influence of porosity inclusion, boundary conditions, and volume fraction index on the vibration response of functionally graded material (FGM) plates using the dynamic stiffness method (DSM). The material properties of FGM are continuously changing along the thickness direction of plates according to the power law with even porosity inclusion. Classical plate theory (CPT) along with the concept of a physical neutral surface is employed to develop the governing differential equation of motion by using Hamilton's principle. The levy type (closed form) solution is used to develop the dynamic stiffness matrix. The Wittrick-Williams algorithm has been employed to compute the exact natural frequency of the FGM plates with porosity inclusion. The efficacy and authenticity of the present formulation have been ascertained by comparing the present results with those of the literature. A comprehensive parametric study has been performed to compute the influence of various geometric and boundary configurations on the vibration response of the FGM plates. © 2022, The Author(s), under exclusive licence to Springer-Verlag France SAS, part of Springer Nature.

International Journal on Interactive Design and Manufacturing

Effect of porosity inclusions on the natural frequencies of the FGM plates using dynamic stiffness method

Synthetic superhydrophobic surfaces have drawn significant interest owing to their water-resistant and self-cleaning applications. However, most of the fabrication practices involve complex processes that are unsustainable to withstand large-scale fabrication to transform into standard industrial practice. The desired durability of these surfaces is another crucial challenge that makes the translation of these products difficult. In this paper, we reported the fabrication of superhydrophobic aluminum alloy with a simpler, low-cost, and eco-friendly technique using the hydrothermal treatment. Subsequently, the surface energy of the processed substrate was modulated using a chemical vapor deposition technique. The developed surface shows an extreme water repellency with a contact angle above 160° and a very low contact angle hysteresis and rolling angle (<5°). Surface morphological characterizations showed the formation of nanoscale hierarchical structures which resulted in a stable Cassie state due to the effective entrapment of air and exhibiting self-cleaning ability. The developed surface showed extreme wetting resilience during exposure to a droplet impingement with an impinging velocity of >2 m/s. Further, these superhydrophobic surfaces were exposed to atmospheric weather conditions to check their robustness. During a rain simulator testing, a developed surface showed low contact angle hysteresis (<10°) after enduring multiple cycles. The processed surface also showed significant de-wetting behavior during condensation experiments and chemical resistance under prolonged exposure. Weathering tests performed under outdoor conditions showed an insignificant influence on the de-wettability of the processed sample. The present study highlights the fabrication of superhydrophobic durable metallic surfaces through a facile and green fabrication route for multifunctional applications. © IMechE 2021.

Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology

Eco-friendly and facile fabrication of superhydrophobic aluminum alloy

Biometric security is a prominent research area with growing privacy and security concerns related to biometric data, generally known as biometric templates. Among the recently proposed biometric template protection schemes, fuzzy commitment is the most popular and reliable. It uses error correcting codes to deal with the significant number of bit errors present in the biometric templates. The high error correcting capability of the underlying error correcting codes is crucial to achieving the desired recognition performance in the biometric system. In general, it is satisfied by padding the input biometric template with some additional bits. The fixed padding approaches proposed in the literature have security vulnerabilities that could disclose the user’s biometric data to the attacker, leading to an impersonation attack. We propose a user-specific, random padding scheme that preserves the recognition performance of the system while it prevents the impersonation attack. The empirical results show that the proposed scheme provides 3 times better recognition performance on the IIT Delhi iris database than the baseline, unprotected systems. Through security analysis, we show that the attack complexity of our proposed work is 2 k, where k is the length of the secret message used to generate codeword, with k≥ 128 bits. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.

Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

On Security of Fuzzy Commitment Scheme for Biometric Authentication

In the current study, we report an excellent high temperature oxidation resistance of AlCoCrFeNi high entropy alloy (HEA) following surface modification. The surface properties of HEA were tailored through a severe surface deformation technique. The as cast HEA exhibited coarse grain B2/BCC microstructure. In contrast, processed specimen showed significant grain refinement along with B2/BCC to FCC phase-transition. The processed specimen demonstrated 11-67% reduction in the oxidation kinetics. Cr2O3 and Al2O3 were the predominant oxides formed in all the oxidized specimens. In addition, Cr, Fe and Co rich spinels were also found in the as cast oxidized specimens. The superior oxidation resistance of the processed specimen is attributed to the microstructural refinement resulting in the formation of protective dense chromia layer. © 2022 Walter de Gruyter GmbH, Berlin/Boston 2022.

Corrosion Reviews

Improving the high temperature oxidation resistance of high entropy alloy by surface modification

The turbulent melting characteristics of hybrid nano-enhanced phase change material (HNEPCM) in a three-dimensional rectangular enclosure has been numerically investigated. The lower and upper walls are partially heated and cooled using constant surface temperature boundary condition and the other surfaces are specified with adiabatic boundary condition. The rectangular enclosure is filled with molten salt phase change material (PCM) of potassium nitrate (KNO3) with melting temperature of 334 °C. The transient melting rates of PCM are investigated by dispersing hybrid mono-dispersed spherical nanoparticles of Aluminum oxide (Al2O3) combined with Silicon dioxide (SiO2), Titanium dioxide (TiO2) and Multi-walled carbon nanotubes (MWCNT). The Rayleigh number (Ra) and particle volume fraction (ϕ) are varied in the range of 106≤Ra≤1010 and 2%≤ϕ≤5%. The turbulent phase change process of PCM is modeled using enthalpy–porosity approach with Lam–Bremhorst k−ϵ turbulence model. The three-dimensional governing equations are discretized using Finite difference technique and computations are carried out using Fortran 90 in-house code. The stronger thermal buoyancy force accelerates the melting rate and the melting pattern indicates the accumulation of large quantity of molten metal in the upper regions of the rectangular enclosure. The average melting velocity and turbulent kinetic energy of pure KNO3 PCM is increased by 51.17% and 77.84% by the addition of Al2O3−MWCNT hybrid nanoparticles. The impact of hybrid nanoparticles on the melting rate and thermal performance of PCM is significant in higher Rayleigh number flows than transitional flows. The present results are validated and are in close agreement with the benchmark experimental results. © 2022 Elsevier Ltd

Journal of Energy Storage

Turbulent melting characteristics of hybrid nano-enhanced molten salt phase change material in rectangular enclosure

Boissonnat and Pritam introduced an algorithm to reduce a filtration of flag (or clique) complexes, which can in particular speed up the computation of its persistent homology. They used so-called edge collapse to reduce the input flag filtration and their reduction method required only the 1-skeleton of the filtration. In this paper we revisit the use of edge collapse for efficient computation of persistent homology. We first give a simple and intuitive explanation of the principles underlying that algorithm. This in turn allows us to propose various extensions including a zigzag filtration simplification algorithm. We finally show some experiments to better understand how it behaves. © Marc Glisse and Siddharth Pritam; licensed under Creative Commons License CC-BY 4.0