(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 phenomenon of light coalescence in Si light emitter during avalanche breakdown is investigated. DC stressing results in light coalescence for low values of current (<25 mA) with total light emission coming out of the junction remaining constant. However, DC stressing with large current values (>40 mA) do not show light coalescence. The light coalescence phenomenon can be reversed when emitters are subjected to higher levels of currents. The purpose of this paper is to explain the difference in light coalescence behavior for large and small values of DC excitations and the reversibility of the phenomenon using hydrogen migration model. © 2002 Elsevier Science Ltd. All rights reserved.

Electrical Engineering

World University root node

Solid-State Electronics

Reversible light coalescence phenomena of Si photo-emitters under stressing at low breakdown currents

Radiation induced leakage current in a variable-thickness SiO 2-on-Si structure (1.0-6.5 nm) is detected and characterized by a novel technique, time-dependent electric field-induced second-harmonic generation (EFISH). The role of second-harmonic generation (SHG) for in situ monitoring of the DC field across the oxide and its utility in understanding the dynamics of the carriers in response to their photo-injection is discussed. Plausible mechanisms responsible for radiation-induced leakage current through thin oxides are used to explain the experimental results.

IEEE Transactions on Nuclear Science

Contactless Ultra-Fast Laser Probing of Radiation-Induced Leakage Current in Ultra-Thin Oxides

In this paper we focus on the problem of designing very fast parallel algorithms for the convex hull and the vector maxima problems in three dimensions that are output-size sensitive. Our algorithms achieve 0(log log 2 n log h) parallel time and optimal O(n log h) work with high probability in the CRCW PRAM where n and h are the input and output size, respectively. These bounds are independent of the input distribution and are faster than the previously known algorithms. We also present an optimal speed-up (with respect to the input size only) sublogarithmic time algorithm that uses superlinear number of processors for vector maxima in three dimensions. © 2003 Elsevier Science (USA). All rights reserved.

Journal of Parallel and Distributed Computing

Faster output-sensitive parallel algorithms for 3D convex hulls and vector maxima

The effectiveness of inherently safer design (ISD) is discussed. There is an alternative philosophy of inherent safety or primary prevention, where the possibility of accidents is removed by the use of safer chemicals and operations. In ISD approach, hazards are identified early and then avoided or at least minimized. The principles of ISD were first enunciated by Trevor Kletz in 1974.

Chemical Engineering

Chemical Engineer

Losing control: Why plants fail

Today an average transmission line is loaded more heavily than ever before and this has given rise to serious problem of voltage instability. A noble method for power system voltage instability estimation and improvement using ANN is presented. The method is based on the fact that reactive power injections at critical buses of the power system help to steer the system away from a developing voltage collapse. The location and quantum of reactive power support has been computed based on sensitivity. The sensitivity matrix is formulated by cascading the output/input sensitivity of multiplayer perceptron model with that of input features versus reactive power injections. The effectiveness of the proposed method is demonstrated on Ward-Hale 6-bus, IEEE 14-bus and IEEE 30-bus test systems. The method can be effectively used to make the system secure against voltage collapse condition in system planning and on-line operation. © 2003 Elsevier Science Ltd. All rights reserved.

International Journal of Electrical Power and Energy System

Sensitivity based voltage instability alleviation using ANN

Employing equipment reliability databases can generate a process of continual improvement. This paper suggests a methodology that uses equipment reliability databases, and a process of benchmarking to establish a continual improvement procedure by learning "how others are doing it". A simple decision-making procedure is suggested too, to assist in prioritizing the processes/equipment that are considered to be improved as well as a methodology to measure the improvement. © 2003 Elsevier B.V. All rights reserved.

Journal of Hazardous Materials

Use of failure rate databases and process safety performance measurements to improve process safety

Barrier to the commercial implementation of optical interconnects between integrated circuits (ICs) center around the fabrication of optical elements on wafers through conventional Si processes. Most other approaches for optical interconnects use direct bandgap emitters that require drastic changes in conventional fabrication processes. In this work, we demonstrate the ability to transmit electrical signals using Si-based components, i.e., the light was generated by biasing a p-n junction at avalanche breakdown voltage, light was coupled through a fiber cable made of SiO2, and detected by an Si-based avalanche photodiode. Results presented demonstrate the switching behavior of light emitter, transmission of signal across the fiber, and measurement of signal limited by the bandwidth of the receiver amplifier.

IEEE Photonics Technology Letters

All Si-based optical interconnect for interchip signal transmission

We present a hierarchical scheme for efficiently maintaining all-pairs approximate shortest-paths in undirected unweighted graphs under deletions of edges. An α-approximate shortest-path between two vertices is a path of length at-most α times the length of the shortest path. For maintaining α-approximate shortest paths for all pairs of vertices separated by distance ≤ d in a graph of n vertices, we present the first o(nd) update time algorithm based on our hierarchical scheme. In particular, the update time per edge deletion achieved by our algorithm is Õ(min{√nd, (nd)2/3}) for 3-approximate shortest-paths, and Õ(min{3√nd, (nd)4/7}) for 7-approximate shortest-paths. For graphs with θ(n2) edges, we achieve even further improvement in update time: Õ(√nd) for 3-approximate shortest-paths, and Õ(3√nd2) for 5-approximate shortest-paths. For maintaining all-pairs approximate shortest-paths, we improve the previous Õ(n3/2) bound on the update time per edge deletion for approximation factor ≥ 3. In particular, update time achieved by our algorithm is Õ(n10/9) for 3-approximate shortest-paths, Õ(n14/13) for 5-approximate shortest-paths, and Õ(n28/27) for 7-approximate shortest-paths. All our algorithms achieve optimal query time and are simple to implement.

Proceedings of the Annual ACM-SIAM Symposium on Discrete Algorithms

Maintaining all-pairs approximate shortest paths under deletion of edges

In the present work, we have demonstrated a novel process for fabricating suspended P+ silicon micromechanical structures such as cantilever beam, microbridge etc. which are recessed in the substrate. The recessed structures formed inside anisotropically etched rectangular cavity, can be further secured by a low temperature planar wafer-bonding process, which also provides the "pull down electrode" for electrostatic actuation of the beam, if required. It is visualized that the recessed structures can be advantageously adapted for many applications such as accelerometer, IR detector, pressure sensors and micro-relay. Since the delicate moving parts are recessed in the substrate, these can be handled and packaged more easily compared to non-recessed structures. We have used standard spin coating process for photoresist application instead of electrodeposition process reported elsewhere which requires an electroplating base. The issues related to photolithography and subsequent etching process on silicon substrate with sharp topographic features are addressed. © 2003 IEEE.

DTIP 2003 - Design, Test, Integration and Packaging of MEMS/MOEMS 2003

P+ silicon recessed micromechanical structures for MEMS applications

A series of helical ceramic springs were manufactured from MgO partially stabilized zirconia to investigate their mechanical properties. Nine springs were machined from zirconia tubing, initially one inch in length, with a rectangular pitch of 16, 14, or 12 turns per inch. An experimental apparatus that both supports and equalizes the applied loads on springs was developed. The spring deflection versus applied load was measured using an optical sight mounted on a micrometer. Deflection data on each spring were collected, plotted and successfully modeled using Hooke's Law. A more extensive model was used to calculate the shear modulus of rigidity and shear stress. This model incorporates the spring dimensions, pitch, applied load, and deflection and provides insight into the effects of the materials of construction and manufacturing technique on the effective shear modulus of spring. A specific manufacturing effect was observed in the initial deflection resulting from the mass of the spring as the pitch was increased. © 2003 Kluwer Academic Publishers.