(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

The ballistic impact performance of a multi-layer material with aluminum foam as the interlayer was investigated numerically in this study. The multi-layer composite material used in this study consists of three functional layers. The ceramic front layer takes the initial impact and converts most of the kinetic energy of the projectile to the energy dissipated in erosion of the projectile material and ceramic. The backing layer which the projectile comes in contact with is a laminated composite fabric which reduces the intensity of the impact by dissipating energy through various forms of damage. The presence of an interlayer in between the front ceramic plate and a composite backing plate has been observed to change the ballistic performance of the composite armor to a great extent numerically. On studying the effect of different inter layers it was observed that the aluminium foam makes the composite layer experience relatively less damage on impact when compared with a specimen without any interlayer. The studies were conducted keeping in mind the weight compensation in each case which led to thickness changes and various distributions of the layers over the cross section. Cause help. © 2017, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.

Mechanical Engineering

World University root node

21st AIAA International Space Planes and Hypersonics Technologies Conference, Hypersonics 2017

High velocity impact on multi-layer materials

Wind tunnel tests on a NACA 0012 airfoil have been carried out to study the transition in aeroelastic response from an initial state characterised by low-amplitude aperiodic fluctuations to aeroelastic flutter when the system exhibits limit cycle oscillations. An analysis of the aeroelastic measurements reveals multi-fractal characteristics in the pre-flutter regime. This has not been studied in the literature. As the flow velocity approaches the flutter velocity from below, a gradual loss in multi-fractality is observed. Measures based on the generalised Hurst exponents are developed and are shown to have the potential to warn against impending aeroelastic flutter. The results of this study could be useful for health monitoring of aeroelastic structures. © 2016 Elsevier Ltd

Journal of Sound and Vibration

Multi-fractality in aeroelastic response as a precursor to flutter

The increasing capabilities of position determination technologies (e.g., GPS) in mobile and hand held device facilitates the widespread use of Location Based Services (LBS). Although LBSs are providing enhanced functionalities and convenience of ubiquitous computing, they open up new vulnerabilities that can be exploited to target violation of security and privacy of users. For these applications to perform, location of the individual/user is required. Consequently they may pose a major privacy threat on its users. So for LBS applications to succeed, privacy and confidentiality are key issues. “Privacy protection” has become the buzz word now days for the users of location based services. This problem has gained a considerable attention among the researcher community also. A state-of-art survey of privacy in location based services containing details of all privacy protection schemes is presented. Further, attack models and their handling mechanism are discussed in comprehensive manner. Finally, some open challenges in the area of location privacy are also demonstrated. © Springer Nature Singapore Pte Ltd. 2017.

Computer Science and Engineering

Lecture Notes in Electrical Engineering

Privacy in location based services: Protection strategies, attack models and open challenges

In this work, we build circuit models to understand the physics of electro-thermal instability and associated thermal runway in advanced ESD protection devices under filamentation. The circuit building methodology takes into account, the instability arising out of inhomogeneous triggering of 2 − D planar bipolar and looks into inherent instability causing the 3 − D phenomenon. Subsequently, the electro-thermal coupling is analyzed to get SPICE model, as we develop a physics based methodology to comprehend the 3 − D localization in the device. Furthermore, we understand the instability through appropriate modeling of localization behavior using area factor (α) and related electro-thermal circuit models. © 2017 Elsevier Ltd

Electrical Engineering

Microelectronics Reliability

SPICE level implementation of physics of filamentation in ESD protection devices

Nanowires (NWs) with a high surface-to-volume ratio are advantageous for bio- or chemical sensor applications with high sensitivity, high selectivity, rapid response, and low power consumption. However, NWs are typically fabricated by combining several nanofabrication and even microfabrication processes, resulting in drawbacks such as high fabrication cost, extensive labor, and long processing time. Here, we show a novel NW fabrication platform based on "crack-photolithography" to produce a micro-/nanofluidic channel network. Solutions were loaded along the microchannel, while chemical synthesis was performed in the nanoslit-like nanochannels for fabricating silver nanobelts (AgNBs). In addition, the NW/NB fabrication platform not only made it possible to produce AgNBs in a repeatable, high-throughput, and low-cost manner but also allowed the simultaneous synthesis and alignment of AgNBs on a chip, eliminating the need for special micro- and/or nanofabrication equipment and dramatically reducing the processing time, labor, and cost. Finally, we demonstrated that the AgNBs can be used as chemical sensors, either as prepared or when integrated in a flexible substrate, to detect target analytes such as hydrogen peroxide. © 2017 The Royal Society of Chemistry.

Chemical Engineering

Fulltext

Nanoscale

A cracking-assisted micro-/nanofluidic fabrication platform for silver nanobelt arrays and nanosensors

Effective surface-enhanced Raman scattering (SERS) detection requires substrates that are typically fabricated using expensive, low-throughput and time-consuming micro-/nanofabrication processes such as photolithography, electron-beam lithography and template- assisted methods Here, a novel micro-/nanofabrication technique for fabricating SERS substrates with hydrophobicity gradients is demonstrated. An inkjet printer enables injecting an AgNO3 solution onto a thiol-functionalized superhydrophobic Cu surface, upon which Ag micro/nanostructures are generated via replacement reactions in the droplet-injected areas. When a mixed solution of target analytes and Au-nanoparticles (Au-NPs) are placed on this substrate, the contact area decreases over time due to the evaporation of the solution and the hydrophobicity of the substrate. As a result, the analyte molecules and Au-NPs are delivered to the Ag micro-/nanostructure clusters, upon which the analyte and Au-NPs are simply and easily concentrated in situ. With the cooperation of Ag nanoplates and Au-NPs, two antibiotics at very low concentrations (e.g., 100 pM 6-aminopenicillanic acid and 50 pM penicillin G sodium) were successfully detected, confirming the higher SERS activity than that of Ag-nanoplate-assembled nanotube arrays or an Ag-NPs decorated graphene electrophoretic pre-concentration device. Hence, this rapid design-to-prototype method for substrates with adjustable wetting properties can be very useful for a SERS platform to detect various target analytes in biosamples. © 2016 Elsevier B.V.

Sensors and Actuators, B: Chemical

Inkjet-printed Ag micro-/nanostructure clusters on Cu substrates for in-situ pre-concentration and surface-enhanced Raman scattering

This study explains a newly developed parallel algorithm for phylogenetic analysis of DNA sequences. The newly designed D-Phylo is a more advanced algorithm for phylogenetic analysis using maximum likelihood approach. The D-Phylo while misusing the seeking capacity of k-means keeps away from its real constraint of getting stuck at privately conserved motifs. The authors have tested the behaviour of D-Phylo on Amazon Linux Amazon Machine Image(Hardware Virtual Machine)i2.4xlarge, six central processing unit, 122 GiB memory, 8 × 800 Solid-state drive Elastic Block Store volume, high network performance up to 15 processors for several real-life datasets. Distributing the clusters evenly on all the processors provides us the capacity to accomplish a near direct speed if there should arise an occurrence of huge number of processors. © The Institution of Engineering and Technology 2016.

IET Nanobiotechnology

Parallel implementation of D-Phylo algorithm for maximum likelihood clusters

The present work focusses on the design and simulation of a thin film bulk acoustic resonator (TFBAR) and a polyimide based TFBAR (PI-TFBAR) and compares the radio frequency (RF) bandpass filter response designed from these resonators. The Polyimide layer in the PI-TFBAR acts as an acoustic wave reflector along with providing mechanical strength to the device. The designed third order bandpass filter has a ladder topology. The insertion loss of the TFBAR filter is 1.69 dB and the return loss is 39.60 dB whereas the insertion loss and return loss are 1.71 and 23.7 dB respectively for the PI-TFBAR filter. The bandwidth of the TFBAR filter is 68.0 MHz and for PI-TFBAR it is 25 MHz. The proposed filter designs, with further optimization, may have application in the 2.6 GHz band, which has been identified by the International Telecommunication Union as a global band for International Mobile Telecommunications and is one of the core bands of LTE-Advanced technology. © 2017, Springer-Verlag Berlin Heidelberg.

Microsystem Technologies

A comparative study on the design and simulation of TFBAR and polyimide-TFBAR based RF bandpass filters

Photoconductive Antenna (PCA) is considered to be simple and compact source for the terahertz (THz) generation. PCA is a common device to generate THz signals. It uses optical-to-electrical conversion to generate the THz radiation. However, the major problem with PCA is the lower efficiency, which is below 1%. The efficiency of PCA systems depends on the current pulse generated by the photo-carriers through the ultrashort laser pulse excitation. In PCA, high efficiency can be achieved by generating a high amplitude current pulse. In this communication a 2D simulation study of current pulse formation is analyzed in the PCA. Also, the effect of different parameters such as input laser power, applied DC bias voltage, antenna and semiconductor material on current pulse generation has been studied to understand the behavior of PCA. The aim of this communication is to analyze the effect of different parameters at low laser power where the screening effect can be neglected. This work is expected to provide better understanding of the mechanism of THz generation and in deciding optimum parameters for maximizing Optical-to-THz conversion efficiency of PCA. © 2015 IEEE.

2015 6th International Conference on Computers and Devices for Communication, CODEC 2015

A parametric study of photo carrier generation in Photoconductive Antenna

Photoconductive antenna (PCA), due to its simple and compact structure, is emerging in recent times as a popular device for generation of Terahertz (THz) frequencies. The working of PCA is based on the optical-to-electrical power conversion technique. The main advantage of the PCA is that it can be used both as a source as well as a detector with little changes in the operating mechanism. In literature, several experimental, simulation and theoretical studied are available for PCA operating as a source. However, very few experimental and simulation studies are available to analyze the performance of PCA as a receiver. In this communication, an effort has been made to analyze the performance of a PCA as a receiver by modeling an equivalent electrical circuit of it, which is based on the physics involved in its operation. © 2017 IEEE.