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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
291

A Method for Automatic Synthesis of Aged Human Facial Images

Gandhi, Maulin R. January 2004 (has links)
Note:
292

NANOSTRUCTURED OPTICAL MATERIALS BASED ON LIQUID CRYSTAL AND POLYMER COMPOSITES

Gandhi, Sahil Sandesh 15 November 2017 (has links)
No description available.
293

ELECTRODEPOSITION OF ORGANOFUNCTIONAL SILANES FOR IMPROVED CORROSION PROTECTION OF METALS

GANDHI, JASPREET SINGH January 2004 (has links)
No description available.
294

ROLE OF NUCLEAR ORGANIZATION, GENE TOPOLOGY AND CHROMATIN ARCHITECTURE IN GENE REARRANGEMENTS

GANDHI, MANOJ SURESH 28 September 2006 (has links)
No description available.
295

REDUCTION / ELIMINATION OF ERRORS IN COST ESTIMATES USING CALIBRATION – AN ALGORITHMIC APPROACH

Gandhi, Raju P. January 2005 (has links)
No description available.
296

Utility-Scale Solar Power Plants with Storage : Cost Comparison and Growth Forecast Analysis

Pragada, Gandhi, Perisetla, Nitish January 2021 (has links)
Renewable energy for energy production, like Solar, is turning out to be very pertinent in today's world [1]. It is very clear that Solar Energy is going to emerge as one of the key sources of energy in future. Moreover, the storage option is going to play an essential role to the future deployment of solar power plants. Concentrated solar power plants with thermal storage, photovoltaic plants integrated with battery energy storage, and hybrid plants are attractive solutions to obtain a stable and dispatchable energy production. Investors or policymakers usually find it challenging to come up with the most feasible solar storage technology because they need to consider techno-economic feasibility, and at the same time, from a market or administrative perspective as well. So, this thesis study will address the key problem which is aimed at investors or policymakers since there is a need to choose the best solar storage technology at a utility level in future based on so many attributes. The thesis project was carried out in two phases which includes forecast modelling & estimations and techno-economic assessment of virtual plants. These two phases helped to address various questions in relation to the problem statement of this study. The entire thesis study broadly covered seven countries spanning across four major regions around the world. The first phase of the thesis, forecast modelling estimations shows how the seven countries will look in future (2020 – 2050) with respect to installed capacity and costs for PV, CSP, and BESS technologies. Some major results from phase 1 include, in low-cost estimates, China will remain to be the market leader in PV & CSP by 2050. In U.S.A and India, the installed costs of PV are projected to decline by 70% by 2050. By 2050, the installed costs of Solar Tower technology are estimated to drop by about 65% in China and Spain. In U.S.A, the prices of BESS technology are likely to fall by around 58 – 60 % by 2050. In the second phase of thesis study, a techno-economic evaluation of virtual plants addressed the aspects which are to be considered for a solar project if it is deployed in future across seven specific countries. Results from this analysis helps investors or policymakers to choose the cheapest solar storage technology at a utility level across seven specific countries in future (2020 – 2050). Key results from this analysis show that, in the U.S.A, by 2050, PV+BESS will be the cheapest storage technology for 4 – 10 storage hours. Addition of another renewable technology will add up more viability to the comparison. In China, Hybrid will be the cheapest storage technology for 4 – 8 hrs by 2050. There is huge potential for deployment of CSP & hybrid plants in future than PV. In South Africa, CSP will be the cheapest storage technology by 2050 for 4 – 10 hours of storage. It is assumed that deployment of BESS projects at utility level starts from 2025 in South Africa. Beyond this, market forces analysis was carried out which offers insights especially for the policymakers of how various drivers and constraints are influencing each solar technology across the specific countries in future. Overall, the entire thesis study provides guidelines/insights to investors or policy makers for choosing the best solar storage technology in future at a utility scale for a particular country. / Förnybar energi för energiproduktion, liksom Solar, visar sig vara mycket relevant i dagens värld [1]. Det är mycket tydligt att solenergi kommer att framstå som en av de viktigaste energikällorna i framtiden. Dessutom kommer lagringsalternativet att spela en väsentlig roll för den framtida distributionen av solkraftverk. Koncentrerade solkraftverk med värmelagring, solcellsanläggningar integrerade med batterilagring och hybridanläggningar är attraktiva lösningar för att få en stabil och skickbar energiproduktion. Investerare eller beslutsfattare brukar tycka att det är utmanande att komma på den mest genomförbara solcellstekniken eftersom de måste överväga teknikekonomisk genomförbarhet, och samtidigt, ur ett marknads- eller administrativt perspektiv också. Så denna avhandlingsstudie kommer att ta itu med nyckelproblemet som riktar sig till investerare eller beslutsfattare eftersom det finns ett behov av att välja den bästa solenergilagringstekniken på en användningsnivå i framtiden baserat på så många attribut. Avhandlingsprojektet genomfördes i två faser som inkluderar prognosmodellering och uppskattningar och teknikekonomisk bedömning av virtuella anläggningar. Dessa två faser hjälpte till att ta itu med olika frågor i samband med problemstudien i denna studie. Hela avhandlingsstudien omfattade i stort sju länder som sträcker sig över fyra stora regioner runt om i världen. Den första fasen i avhandlingen, prognosmodelleringsuppskattningar visar hur de sju länderna kommer att se ut i framtiden (2020 - 2050) med avseende på installerad kapacitet och kostnader för PV-, CSP- och BESS -teknik. Några viktiga resultat från fas 1 inkluderar, i lågkostnadsuppskattningar, att Kina kommer att vara marknadsledande inom PV och CSP år 2050. I USA och Indien beräknas de installerade kostnaderna för PV minska med 70% år 2050. Av 2050 beräknas de installerade kostnaderna för Solar Tower -teknik sjunka med cirka 65% i Kina och Spanien. I USA kommer priserna på BESS -teknik sannolikt att sjunka med cirka 58 - 60 % år 2050. I den andra fasen av avhandlingsstudien behandlade en teknikekonomisk utvärdering av virtuella anläggningar de aspekter som ska övervägas för ett solprojekt om det används i framtiden i sju specifika länder. Resultaten från denna analys hjälper investerare eller beslutsfattare att välja den billigaste solenergilagringstekniken på en användningsnivå i sju specifika länder i framtiden (2020 - 2050). Viktiga resultat från denna analys visar att i USA, år 2050, kommer PV+BESS att vara den billigaste lagringstekniken på 4 - 10 lagringstimmar. Tillägg av en annan förnybar teknik kommer att öka jämförbarheten. I Kina kommer Hybrid att vara den billigaste lagringstekniken i 4-8 timmar fram till 2050. Det finns en enorm potential för distribution av CSP & hybridanläggningar i framtiden än PV. I Sydafrika kommer CSP att vara den billigaste lagringstekniken år 2050 för 4 - 10 timmars lagring. Det antas att distributionen av BESS -projekt på verktygsnivå börjar från 2025 i Sydafrika. Utöver detta genomfördes marknadskravsanalys som ger insikter speciellt för beslutsfattarna om hur olika drivkrafter och begränsningar påverkar varje solteknik i de specifika länderna i framtiden. Sammantaget ger hela avhandlingsstudien riktlinjer/insikter till investerare eller beslutsfattare för att välja den bästa solenergitekniken i framtiden i en nyttoskala för ett visst land.
297

Multi-Objective Optimization of Torque Distribution inHybrid Vehicles

Gandhi, Ansh, Fartyal, Ankur January 2020 (has links)
Electrification is one of the mega-trends in the transportation and automotive industry today. Boththe alarming environmental conditions and the ever decreasing fuel reserves are driving the shifttowards hybrid, all electric and alternative fuel source vehicles. This thesis work is another smallstep towards studying, addressing and handling this issue while also laying the groundwork for developingand moving towards more efficient and commercially viable vehicles.This thesis work aims at investigating the trade-off offered by optimal control techniques betweenenergy consumption and reference tracking for torque allocation to the various actuators available topropel a hybrid electric vehicle. The particular vehicle under consideration has two electric motorsat the rear wheels and an internal combustion engine along with an integrator starter generatordriving the front wheels. The torque allocation problem is originally solved by proposing a one stageoptimization strategy (OSOS) that takes into account actuator limits, losses, and objectives throughconstraints. The performance of this formulation is presented over two simulated test tracks on apareto front where the advantage on relaxing complete reference tracking becomes visible. Next,two new formulations each as a two stage optimization strategies (TSOS) are proposed, the mainobjective being to split the original formulation into two parts. One addressing energy optimalityand the other addressing reference tracking of total wheel torque and yaw moment request fulfilment.These formulations are then similarly investigated and presented in comparison with the originalformulation. In developing the formulations, an assumption about the loss models is made andthe problem size of the second stage quadratic program is significantly reduced. The problems areappropriately scaled and made mathematically robust to handle the constraints and inputs in theoperating range. As reference tracking for the vehicle is split into lateral and longitudinal torquerequests from the vehicle, this becomes a multi-objective optimization problem. To further studythe behaviour of these formulations, they are given constant inputs and simulated over a single timestep. The effect of changing hybridization level, i.e, the amount of electrical energy used comparedto fuel energy on the behaviour of these formulations is also explored. One of the effects of the twostage formulations was the confinement of solutions within a reasonable error for the majority ofchosen weights due to the energy considerations in the first stage. The proposed formulations wereable to generate results close but not equal to the original formulation on the pareto front. Anotherfinding was that due to the implementation of two actuators at the rear of the vehicle, a desired yawrate could be achieved at no additional energy cost because of regenerative and propulsive torquesgenerated respectively on either side of rear axle for torque vectoring. Furthermore with a dedicatedsolver, the TSOS could present an interesting alternative to enhance independent development invehicle dynamics control and energy management of the vehicle. / För att minska miljöpåverkan av utsläpp från bilkörning är det ett ökat fokus på elektrifieringav bilar och förnybara bränslen. Detta examensarbete försöker att bidra till smartare användningav energiresurser under körning. Syftet är att bygga upp kunskap om effektiv energihantering ihybridfordon. En optimeringsbaserad reglerteknik används för att allokera drivmoment till olikaaktuatorer på drivlinan av ett hybridfordon och bestämma en balans mellan energieffektivitet ochmomenthantering för bättre körbarhet. Det studerade hybridfordonet har två elektriska motorermonterade på bakaxeln därtill har en förbränningsmotor och integrerad startmotor och generator påframaxeln. Momentallokeringsproblemet är ursprungligen löst med hjälp av en optimeringsstrategisom sker i ett steg som tar hänsyn till exempelvis systemets begränsningar och energiförluster.Denna formulering är förändrad för att skapa två olika formuleringar av en optimeringsstrategi somsker i två steg. Prestandan för de olika strategierna jämförs därefter på två olika simulerade testbanoroch visualiserades med hjälp av en paretofront. Syftet med att dela upp beräkningen i tvåsteg är för att göra det modulärt och förenkla gränssnittet mellan fordonsdynamik och fordonsenergihantering.Med denna uppdelning kan det ske oberoende forskning och utveckling inom bådaområdena. Det första steget hanterar energin och det andra steget hanterar hur väl systemet kanuppnå referensfördelningen av drivmoment och girmoment. De nya formuleringarna är baserade påen antagen förlustmodell och är omvandlade via skalning för att därefter jämföras med den ursprungligaformuleringen för att identifiera unika beteenden. En effekt av två-stegsformuleringen var attlösningarna begränsades inom ett rimligt felområde som en följd av energihanteringen i det förstasteget . Lösningarna från två-stegsformuleringen kom väldigt nära resultaten för den ursprungligaformuleringen. Två-stegsformuleringen kan vara ett bättre alternativ för att ha en modulär reglersystemsarkitekturom den kan utvecklas vidare med en dedikerad programvara i fordonets styrenhetsom använder ett lämpligt sätt för att räkna ut det optimeringsproblemet.
298

Theoretical and numerical prediction of ion mobility for flexible all-atom structures under arbitrary fields and subject to structural rearrangement. An initial probing into the effects of internal degrees of freedom.

Viraj Dipakbhai Gandhi (7033289) 18 April 2024 (has links)
<p dir="ltr">Ion mobility spectrometry (IMS), with its unparalleled ability to separate and filter ions based on their overall size before channeling them into a Mass Spectrometer, has placed itself as a cornerstone of the modern Analytical Chemistry field. IMS provides an orthogonal separation, aiding in the identification and analysis processes of various compounds. While there have been many inventions for ion mobility (IM) devices with exponential growth in the separation capability in the past few years, there is very little emphasis on the theoretical explanation. For example, most modern IMS devices often use a high ratio of electric field to gas concentration (E/n) as it provides better separation capabilities. However, the interaction between ion and gas at such E/n cannot be explained by current IM theories as they ignore several critical factors such as the increase in ion’s energy due to energetic collisions, the energy loss/transferred in the internal degree of freedoms, and change in the ion’s structure, requiring empirical data to identify ions after separation. The thesis presented here contributes towards bridging this gap by elucidating the complex interplay of forces and interactions that govern the ion separation process, thereby explaining on how these mechanisms can be further exploited for refined separation and advancing the computational approach to identify the separated ion.</p><p dir="ltr">To explain the ion-gas interaction under high E/n, this research extends the Two-Temperature Theory (2TT) up to the fourth order approximation. The central idea of the 2TT is to solve moments of the Boltzmann equation for the ion’s velocity distribution involving ion-gas collisions. The research shows a decreasing error between each subsequent approximations, indicating convergence. This advancement is demonstrated through the development and application of our in-house program, IMoS, and validated against experimental data for small ions in monoatomic gases. This research also justifies the mechanisms of increasing and decreasing mobility as the electric field is increased by explaining the interplay between the interaction potential and the collision energy.</p><p dir="ltr">Subsequent chapters investigate the impact of internal degrees of freedom (rotational and vibrational) on ion mobility. This includes pioneering work with the Structures for Lossless Ion Manipulations (SLIM) device to separate isotopomers, alongside computational advancements in simulating these effects, leading to the development of IMoS 2.0. In IMoS 2.0 software an ion is placed in a virtual drift tube with electric field, where it is free to rotate and translate upon collision. The research notably uncovers the role of rotational degrees of freedom in isotopomer separation, a previously underexplored area.</p><p dir="ltr">To ascertain the effect of the vibrational DoF and differentiate from the ion’s structural expansion and heating resulting from energetic collisions, a combined simulation of ion mobility and molecular dynamics (IM-MD) was performed. This analysis revealed that structural expansion plays a dominant role for the cause of deviation at high E/n, to such an extent that the vibrational DoF (or inelastic collisions) can normally be disregarded. Moreover, the research also indicates that using a combination of IM-MD simulation, one can identify accurate gas-phase structure of the ion at any temperature from a pool of probable structures.</p><p dir="ltr">Guided by these conclusions, the research now takes a significant step forward by aiming to accurately characterize protein structures in the gas phase using IM-MD simulation. Traditional MD simulations provide larger structures since the force field is not optimized for the gas-phase simulation. To address this, a biasing force towards the center of the protein is applied, compressing it. This method efficiently explores multiple feasible configurations, including those obscured by energy barriers. This strategy generated structures that closely align with the experimental evidence.</p>
299

A CAD/CAM interface for computer-aided design of cams

Gandhi, Ashit R. 12 March 2013 (has links)
The purpose of this thesis is to provide a complete package for the design and three dimensional modeling display of cams. The software produced as a part of this work will operate as a module of CADAM to produce cam designs and enter the resulting cam as a CAD model and produce the graphical display of the cam. In addition to the introductory material, this thesis is divided into four sections. The section on the graphics packages used in this thesis includes a brief history and capabilities of each of the packages. The second section details the procedure to be adopted in order to design a cam. The next section details ANICAM, the program that has been developed to incorporate the design and display procedure. The fourth section of this thesis contains recommendations for further work in this area. The theoretical work in this project is a combination of original derivations and applications of the theory in the design literature. / Master of Science
300

Feature-based geometric modeling using B-spline surfaces and a natural language approach

Gandhi, Ashit R. January 1989 (has links)
Traditionally, design geometries are represented using orthographic views which require a human being to interpret them and recognize geometric features to evaluate the design. Solid modeling systems have made the task somewhat easier, but they often require tedious and complex operations using simple geometric primitives. This has led to investigation of modeling systems which allow the creation of assemblies the way engineers conceive them - as features. To be able to efficiently describe models in terms of features, a rich set of feature descriptors are necessary. An exhaustive study of English words describing form, shape, feature, shape altering transformations and surface conditions was done to establish a wide vocabulary for feature based description. Classification based on topology and form was done and prototype constraint relations were implemented to differentiate between some features. A feature is created from a topological group by computing points and interpolating them with uniform rational B-spline patches. Control points needed to compute the patches are computed from the interpolation points by an inverse relation. A designer-oriented modeling language, based on simple English syntax, was devised to specify procedures to be executed by the modeler in order to create features using minimal user input. / Ph. D.

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