(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

Mumbai city is the economical capital of India and is situated about midway on the western coast of stable continental region of Peninsular India. Major part of the city being of reclaimed land, the soil type is of alluvium, sand, and recent conglomerate. There are some bigger water bodies within the city range. In this study, an attempt has been made to study the susceptibility of soil liquefaction using simplified empirical procedure based on number of blow counts (N values) of the soil layers from standard penetration test. The liquefaction susceptibility is quantified in terms of factor of safety along the borehole depths at available borehole locations using earthquake-induced cyclic stress on the soil and the cyclic resistance of the soil to withstand the load. The factor of safety against liquefaction is evaluated at different sites for two peak ground acceleration (PGA) levels pertaining to 10 and 2 % probability of exceedance in 50 years corresponding to uniform hazard response spectra for Mumbai city with 475- and 2,475-year return period, respectively. Contour maps are prepared that display the factor of safety at different depths for earthquake magnitude of M w 6.5. These contour maps show the liquefaction vulnerability at different sites in the city. © 2012 Springer Science+Business Media B.V.

Civil Engineering

World University root node

Natural Hazards

Soil liquefaction studies at Mumbai city

In the present work, we report preparation and characterization of silicon carbide (SiC) films obtained by RF magnetron sputtering using a SiC ceramic target. The films were deposited in Ar ambient without external substrate heating. The residual stress of the films was measured as a function of sputtering parameters. The stress of the as-deposited films was observed to be compressive for the entire range of sputtering parameters used in the present work. Postdeposition annealing at 400 °C in N 2ambient was useful in reducing the stress in the films. On sequentially annealing the films at higher temperatures (600 and 800 °C), the nature of the stress changed from low compressive to high tensile. A superhard SiC film with low residual compressive stress (58.7 MPa) was obtained with hardness and Young's modulus values of 49.86 GPa and 363.75 GPa respectively. The x-ray diffraction pattern revealed that the films were either amorphous or nano-crystalline, depending on the deposition parameters and postdeposition annealing temperature. Atomic force microscopy roughness results confirmed good chemical stability of the films in potassium hydroxide and buffered hydrofluoric acid solutions. Several types of micro-structures were fabricated to demonstrate the feasibility and compatibility of these films in MEMS fabrication. © 2012 IOP Publishing Ltd.

Electrical Engineering

Journal of Micromechanics and Microengineering

Mechanical and structural properties of RF magnetron sputter-deposited silicon carbide films for MEMS applications

The geographical areas that are considered to be popular and interesting are called Region of Interest (ROI). There are multiple sources that can be used for erecting the ROIs such as user trajectory, POI databases, internet news etc. A tourist spot, historical region, monuments, a forest reserve, city, state or country's administrative boundaries are considered as the ROI objects. The interesting facts of the regions can be used for on-the-spot infotainment (information + entertainment) while user is walking, driving or just sitting idle on the flight. One may want the information in different level of details based on the interests, travel direction, and speed. The best way to get the recent information is going through the internet news, discussion forums, and encyclopedias on the web. The challenge is that there is no universal database available that contains the region information along with the location based search capabilities. The maintaining the granularity of the information based on the size or the details of the region adds more challenges. The broader idea of our work is to use the existing LBS infrastructure to track the user and achieve other navigation objectives in the system. However, the freely available up-to-date internet infrastructure is used as the information source. Initially, the user location is determined by the conventional methods. In order to relate the location with the web content, we use the semantic labels associated to the underlying location. The semantic labels are fetched by using reverse geocoding that returns the local attractions, street city, state and country names etc. Then these labels are used to search the associated detailed content in the web. The region data is maintained in two forms i.e. locally populated database and the web databases. The locally populated database can be updated on the preconfigured time interval in order to avoid data staleness problem. We have used Wikipedia as the internet data source in our prototype. The further research is in progress extracting the ROI information from the POI databases with their spatial and non-spatial attributes. © 2012 IEEE.

Computer Science and Engineering

Proceedings - 2012 IEEE 13th International Conference on Mobile Data Management, MDM 2012

Extracting Region of Interest (ROI) details using LBS infrastructure and web-databases

Huge information is inherently associated with certain places in the globe. The ancient cities have multiple locations with large historical, geographical, cultural and architectural specialties. E-Learning systems allow the learners to learn irrespective of their time and place. The location based learning (LBL) is another aspect where the site seeing, and touching the building walls are the means of real-time experience of the sites. This manifestation motivates us to extend the capabilities of conventional E-learning systems so that the information can be accessed at the real-time based on the user's location. In this paper, the e-Learning system is used for the LBL with the help of navigation capabilities without modifying the existing systems. The learning content geocoding, reverse-geocoding, and real-time learning plan generation based on the user preferences and constraints have been proposed. The on-the-way learning is another aspect of the LBL that has been proposed with a prototype implementation. The implemented system is a flexible and visually appealing LBL platform with a possibility to get the real-time location specific information both from webdatabases and locally stored content.

IET Conference Publications

Fusion of navigation technology and e-learning systems for on-the-spot learning

WC-Co-Cr coatings were deposited on some hydroturbine 13Cr4Ni and 16Cr5Ni steels by the detonation-gun spray process. An in-depth characterization of the as-sprayed coating was done using X-ray diffraction (XRD) and scanning electron microscopy (SEM)/energy-dispersive X-ray spectroscopy (EDS) techniques. Microhardness and porosity measurements were also made. The coating was found to have a typical splat-like morphology with some indications of unmelted carbide particles. The XRD results showed the presence of WC as the primary phase along with W2C and Co6W6C as secondary phases. Furthermore, the slurry erosion behavior of the coatings was investigated to ascertain the usefulness of the coatings to reduce the slurry erosion of the steels. The effect of four operating factors viz. the velocity, impact angle, concentration, and particle size on the slurry erosion of coated and bare steels has been studied using a high-speed jet-type test rig. The sand used as an erodent was collected from a power plant to replicate the actual turbine conditions. It has been observed that the given cermet coating can enhance the erosion resistance of the steel. Velocity was found to be the most significant factor affecting the erosion behavior of the coating, whereas it was the erodent particle size in the case of uncoated steel. As evidenced from the SEM images, the platelet mechanism of erosion seemed to be the prominent one, causing the removal of material from the surface of the steel, whereas for the coating, the formation and interlinking of cracks resulted in the removal of material. © The Mineral, Metals & Materials Society and ASM International 2012.

Mechanical Engineering

Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science

Parametric study of slurry-erosion of hydroturbine steels with and without detonation gun spray coatings using taguchi technique

Erosion in industrial appliances causes huge loss of valuable resources especially when solid particles are present in the working medium. A number of erosion models that are available in the literature claimed to predict the erosion response. In this work, five erosion models have been evaluated using computational fluid dynamics (CFD) methodology. Three most commonly used experimental test rigs (solid particle and unsubmerged slurry jet type and pot type) have been simulated and comparisons with the experimental results have been performed. The study helps in understanding the effect of fluid medium and flow pattern on the erosion process. The knowledge acquired shows that phenomenological based erosion models give better results considering the wide range of operating parameters. The in-depth study of the flow field shows the possibility that erosion mechanism, being parameter dependent, could change with location on the same specimen.

TMS Annual Meeting

Numerical simulation of erosion using computational fluid dynamics

In recent years, spillway rehabilitation has increased in importance and become the subject of many projects worldwide. One solution for this problem is the implementation of a new type of labyrinth spillway, called Piano Key Weir (PK-Weir ). This is an excellent alternative for increasing the overflow capacity of existing dams. Similarly to traditional labyrinth weirs, the hydraulic capacity of a PK-Weir is a function of its geometrical characteristics. Currently, there is a lack of systematic experiments, and the existing data does not allow the proposition of a universal design procedure. This paper reviews the previous studies on the efficiency of planned and built PK-Weirs. The results are evaluated by comparing an actual PK-Weir's discharge to that theoretically obtained for a sharp-crested spillway with crest length equal to the width of the PK-Weir for a given hydraulic head. On the basis of this evaluation, a preliminary design procedure is proposed. © 2012 American Society of Civil Engineers.

Center for Environmental Sciences & Engineering

Journal of Hydraulic Engineering

Discharge capacity of piano key weirs

Given a set of points P ⊂ ℝ d, the k-means clustering problem is to find a set of k centers C = {c 1,...,c k}, c i ∈ ℝ d, such that the objective function Σ x∈P d(x,C) 2, where d(x,C) denotes the distance between x and the closest center in C, is minimized. This is one of the most prominent objective functions that have been studied with respect to clustering. D 2-sampling [1] is a simple non-uniform sampling technique for choosing points from a set of points. It works as follows: given a set of points P ⊆ ℝ d, the first point is chosen uniformly at random from P. Subsequently, a point from P is chosen as the next sample with probability proportional to the square of the distance of this point to the nearest previously sampled points. D 2-sampling has been shown to have nice properties with respect to the k-means clustering problem. Arthur and Vassilvitskii [1] show that k points chosen as centers from P using D 2-sampling gives an O(logk) approximation in expectation. Ailon et. al. [2] and Aggarwal et. al. [3] extended results of [1] to show that O(k) points chosen as centers using D 2-sampling give O(1) approximation to the k-means objective function with high probability. In this paper, we further demonstrate the power of D 2-sampling by giving a simple randomized (1 + ∈)-approximation algorithm that uses the D 2-sampling in its core. © 2012 Springer-Verlag.

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

A simple D 2-sampling based PTAS for k-means and other clustering problems

This paper presents experimental studies for the production and propagation of an electron beam from a single gap pseudospark discharge based plasma cathode electron (PCE) gun. The generated electron beam has been successfully propagated for more than 25 cm in a gaseous environment without application of external guiding magnetic field at different operating conditions. The electron beam losses due to recombination with ions and collision with walls of drift space have been estimated. The electron beam profile has also been analyzed in the drift region of the gun. © Published under licence by IOP Publishing Ltd.

Fulltext

Journal of Physics: Conference Series

Investigation of electron beam parameters inside the drift region of plasma cathode electron gun

Energy detection in frequency domain is a preferred technique for the spectrum sensing and the accuracy of frequency estimation depends on the DFT size. A new technique for energy detection is proposed here. Instead of computing full length (N-point) DFT of the whole data, this paper proposes a two level (coarse-fine) approach. In the first (coarse) level, time averaging of smaller size (L≪N) data blocks of the whole data and its DFT are computed and Neymen Pearson based detection is performed to determine the presence of energy in the subbands. In the second level (fine), Goertzel algorithm is applied to determine the fine estimates in those subbands. Matlab based experiments were performed to verify the proposed method. Simulation result also shows that this method can be applied for non-uniformly occupied spectrum also. The complexity of this approach is evaluated and it is about 51% computationally more efficient at -5 dB signal to noise ratio of received signal. © 2012 IEEE.