358 research outputs found
Read counts at multiple attenuation levels as an object localization technique using passive RFID tags
No full textRadio Frequency Technologies (RFID) are experiencing rapid development and business, retail, manufacturing and healthcare are the major application areas benefiting from it. We describe and analyze an algorithm which helps in tracking of medical equipment and personnel and patients in a Trauma Bay. We adapt the Read Count algorithm to be used at multiple attenuation levels as a localization technique. The input parameter to the algorithm is the read count value which gives a measure of number of times the back-scattered radio frequencies from passive tags has been received by the antenna. Special attention has to be given to the placement of antennas to get the optimum result. The detection of multiple tags and human occlusion are two major concerns which we have tried to solve by suing multiple horizontal antennas along with 1 vertical antenna. We have discussed the results and analysis of such a configuration and accordingly given a conclusion. The problems associated with the configuration have also been discussed which can form part of future work.M.S.Includes bibliographical referencesby Ankit Sard
Book review: Age of entanglement: German and Indian intellectuals across Empire by Kris Manjapara
No full text"Age of Entanglement: German and Indian Intellectuals across Empire." Kris Manjapara. Harvard University Press. January 2014. --- In this book, Kris Manjapara sets out to explore patterns of connection linking German and Indian intellectuals from the nineteenth century to the years after the Second World War. The author attempts to trace the intersecting ideas and careers of a diverse collection of individuals from South Asia and Central Europe who shared ideas, formed networks, and studied one another’s worlds. Ankit Kumar recommends this book to those studying world history, geopolitics, postcolonialism and development
Numerical study of heat transfer in two-phase flows
No full textHeat transfer in multiphase flow plays an important role in nature and in numerous industries such as petrochemical, automotive, food processing, ocean engineering etc. It is becoming increasingly crucial to design more efficient industrial systems to reduce the environmental impact of industrial activities because of global warming and growing awareness about sustainability. To design these efficient systems it is important to thoroughly understand the details of heat transfer in multiphase flow. This thesis follows the method of Direct Numerical Simulation (DNS) to provide a detailed physical insight of the fluid motion and heat transfer in the model. To accurately model the two phase flow the Coupled Level Set Volume Of Fluid (CLSVOF) method is used. The main advantage of using the CLSVOF method is that it can accurately capture the interface geometry and it has excellent volume conservation capability. The work presented here is an extension to an in-house code developed at TU Delft for Direct Numerical Simulation of two-phase flows using the CLSVOF method. The existing code has been thoroughly validated for the fluid and interface motion but the validation of the heat transfer model remains an unaccomplished task till now. Therefore, the main objective of this thesis is to validate the heat transfer model and then to study the heat transfer in droplets coalescence using this model. The validation of the heat transfer model was accomplished by calculating the Nusselt number distribution over a bubble surface and comparing it to the available literature. Both the model results and the information from the literature showed very good agreement with each other. After completing the model validation, this model was used to study the heat transfer phenomenon between two coalescing droplets and the surrounding fluid. The results of the droplets coalescence are as per the expectations and are discussed in detail in this thesis. In the process of doing these analyses different ways of calculating the local Nusselt number and the global Nusselt number have been discussed. The validation of the heat transfer model and the analysis done for the case of coalescing droplets paves the way for conducting more complex heat transfer analysis in two-phase flows using this model.Mechanical Engineerin
Analysis of Clothing Air Layer During Walking Using 3D Scanning Method
No full textRõivasisesed- ja välised õhukihid omavad suurt rolli inimkeha ja keskkonnavahelistes soojusülekannetes. Selleks, et mõista rõivaste soojuslikke omadusi, on oluline kindlaks määrata rõivasiseste õhukihtide ja kokkupuuteala suurus. Varasemalt on rõivasiseste õhukihtide ja kokkupuutealade suurusi inimkeha dünaamilises olekus uuritud ainult 3D rõivasimulatsiooni tarkvara kasutades. Antud lõputöös uuritakse eelnimetatud parameetreid kasutades painduvate liigestega mannekeeni ning 3D kehaskannerit. Lõputöö eesmärk on mõõta kõndimise ajal rõiva ja keha vahele tekkiva õhukihi ja kokkupuuteala suuruste muutusi erinevatel kehaosadel. Töö koosneb neljast peatükist - teoreetiline taust, metoodika, tulemused ja diskussioon. Antud lõputöös saadud tulemused ei ole otseselt võrreldavad reaalse liikumisega, sest mannekeeni skanneeriti staatilises olekus, kus puuduvad inertsjõud ning ainus mõjuv jõud on gravitatsioon. Tulemustest selgub, et erinevates keha positsioonides muutub rõivasisese õhukihi suurus enam just jäsemetel, sest käed ja jalad liiguvad torsoga võrreldes tunduvalt rohkem. Lisaks saab sellest järeldada, et soojusülekannetel inimkehalt keskkonda, on jäsemetel suurem mõju kui torsol.The enclosed air layer and boundary air layer play a significant role in heat transfer process. It is important to obtain the air gap thickness underneath the clothing in order to understand the thermal properties of the garment. Air gap thickness and contact area have been determined during walking using 3D garment simulation software. However, these results have not been validated yet. In this thesis, a walking movement is being analyzed and the data regarding air gap thickness and its variation during body movement was studied in detail using accurate 3D scanning and post-processing method. The aim of this thesis is to measure the change in air gap thickness and contact area in different body parts for various body positions during walking movement. The thesis contains theoretical background, methods, results and discussion. The results obtained from this study do not reflect the real-life scenario, because the manikin was scanned in static positions, where inertia forces were absent and the only acting force was gravitation. The variation in air gap thickness was greater on arms and legs than on the thorax due to higher swinging movement of the limbs. Therefore, the limbs may have a higher effect of forced convective heat transfer
RETRACTED ARTICLE: Psychological predictors behind the intention to drink and drive among female drivers: Application of extended theory of planned behavior
No full textWe, the Editor and Publisher of Traffic Injury Prevention, have retracted the following article: Ankit Kumar Yadav. Psychological predictors behind the intention to drink and drive among female drivers: Application of extended theory of planned behavior. Traffic Injury Prevention. 2020. https://doi.org/10.1080/15389588.2019.1703961. The author has requested the retraction of his article due to an error in one of the collected psychological measures. During data extraction, the responses for ‘attitude’ and ‘intention’ measures were switched and may have influenced the findings from the developed regression model and its results. As a result, the Editor and Publisher have agreed to retract the article in full. We have investigated and have been informed in our decision-making by our policy on publishing ethics and integrity and the COPE guidelines on retractions. The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as “Retracted”.</p
Pianotap: improving tap authentication on mobile devices
No full textIn this thesis, we study authentication on mobile devices by performing simple taps on the touchscreen. First, we have replicated a previously proposed system Pass- Chords - a tap based authentication system. Based on the lessons learned, we present an improved system called Pianotaps, which theoretically provides an orders of mag- nitude larger password space. We conducted a preliminary informal user study of PassChords, Pianotaps and PINs towards understanding the bene ts and drawbacks of these approaches. Our results indicate that Pianotaps provides enhanced security over shoulder sur ng attacks while also being faster to authenticate with.M.S.Includes bibliographical referencesby Ankit Sha
Bilateral pneumothorax in COVID recovery: Tale of two cases
No full textSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection leading to coronavirus disease 2019 (COVID-19) mainly affects the lungs leading to complications of acute lung injury. Pneumothorax has been observed as a complication in COVID-19 cases requiring urgent intervention and may indicate poor prognosis in view of severe underlying lung damage. Bilateral pneumothorax is an even dreaded and rare complication requiring immediate recognition and management. We present two similar cases of bilateral pneumothorax with COVID-19 pneumonia with none requiring positive pressure ventilation and no preexisting lung disease. Our cases are a reminder about the severity of lung damage in COVID-19 and that a good vigilance is required in the event of an acute deterioration
Homogenization and elastic-plastic transitions in random and FGM microstructures
Full text linkThe research presented here uses homogenization as a tool to estimate the effective properties of heterogeneous materials with varying microstructures. Separation of scales (Micro (d), Meso(δ), Macro (L)), in these microstructures leads to the problem of determination of the Representative Volume Element (RVE) that corresponds to the effective properties of materials. Microstructural randomness is inherent in these materials and hence we study the scaling from Statistical Volume Element (SVE) to RVE. Using Hill condition, the RVE is achieved when the material response becomes independent of the two boundary conditions (kinematic and static boundary condition) setup on the SVE. Elastic responses of 2d microstructures such as two-phase random checkerboard are considered, and RVE of the same is also identified. This technique is consistent with the Hill-Mandel macrohomogenity condition. We propose to homogenize the elastic response of FGM (functionally graded materials) type microstructure in 3d using the same technique. Since the Hill condition is independent of the microstructure, hence it is counter-intuitive that FGM microstructure can- not be easily homogenized using the same approach. The inelastic response of FGM microstructures in 2d and 3d are also studied here. The elastic-plastic transition in multiphase materials is smooth (not sudden), suggesting fractal nature of the evolving plasticity in the material. An attempt is made to calculate the fractal dimension of these evolving plastic grains in the 2d and 3d FGM microstructure. In 3d, this results in massive simulations performed in parallel using commercially available FEM package called ABAQUS. The simulations were carried out using the computational resources available at the National Center for Supercomputing Applications (NCSA). This opens up the possibility of assessing plastic damage in material through fractals. Preliminary experimental study using viscoelastic materials for FGM microstructure is also presented here. Furthermore, we also present the scaling effect under finite mesoscale size quantified in the form of normalized scaling function. We propose to study the effect of this scaling function for the two-phase correlated microstructures of Gaussian type, formulation of which is also presented here. Comparison with existing experimental data shows our numerical model is well in agreement with the experimental data for various volume fractions of the constituent phases.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2017-05-01The student, Ankit Saharan, accepted the attached license on 2015-04-22 at 10:05.The student, Ankit Saharan, submitted this Dissertation for approval on 2015-04-22 at 10:16.This Dissertation was approved for publication on 2015-04-23 at 07:34.DSpace SAF Submission Ingestion Package generated from Vireo submission #8012 on 2015-07-22 at 14:26:06Made available in DSpace on 2015-07-22T22:45:57Z (GMT). No. of bitstreams: 4
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Previous issue date: 2015-04-23Embargo set by: Seth Robbins for item 80013
Lift date: 2017-07-22T22:46:21Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemLimited Restriction Lifted for Item 80013 on 2017-07-23T09:15:24Z
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