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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.
31

Numerical simulation of Large Solar Hot Water system in storage tank

Shue, Nai-Shen 06 September 2012 (has links)
This research is aimed to study the storage tank design parameters effects on the efficiency of the large solar hot water system. Detailed CFD simulation for the storage tank coupled with TRNSYS program simulation for the entire solar hot water system will be performed to study the system performance under various thermal stratification baffles design for the storage tank. The study is made for three representative cities of Taiwan by input their typical-meteorological-year data (TMY data). The results indicate the performance of a large solar hot water system can be significantly improved with proper designed thermal stratification baffles in the storage tank.
32

The dynamic response of floating tank under wave motion

Li, Liang-cheng 22 January 2009 (has links)
In the present study, a two-dimensional numerical model based on a time-independent finite difference method was developed and the model is used to analysis the dynamic interaction among wave, sloshing fluid in tank and the floating tank. The free surface of wave and sloshing fluid in the tank are all assumed to be a single value function and the wave breaking is, therefore, not considered in the study. The numerical model is firstly validated by some bench make studies. Extensive simulation were made to discuss the effects of geometry of the floating tank, the ratio of depth to breadth of fluid in tank, the fundamental freq of floating tank ¡V structure system etc.
33

Fluid and suspension hydrodynamics in the impeller discharge flow of stirred tanks

Yu, Ziyun January 2004 (has links)
<p>The hydrodynamics of an agitated tank have been studied byphase-Doppler anemometry. The focus is on the impeller anddischarge region of a 45o pitched blade turbine (PBT). Thestudy includes agitation of pure water as well as of a dilutesuspension of process particles. A three-dimensionalphase-Doppler anemometer is used to measure local,instantaneous, three-dimensional velocities of the fluid and ofthe suspended particles. A shaft encoding technique is used toresolve the turbulent fluctuations from the periodic velocityfluctuation due to the impeller blades, and to provide moredetailed information about the variations relative to theimpeller blade. Velocity bias is corrected for by the total3-dimensional velocity.</p><p>The mean flow field, the fluctuating velocities, and thecomplete Reynolds stress tensor, are reported for the liquidphase flow. The periodic fluctuations in the flow that aregenerated by the impeller blades are eliminated in theexamination of the turbulence. The anisotropy of the turbulenceis assessed by the invariants of the anisotropy tensor. Thetrailing vortex structure is demonstrated to be associated withhigh kinetic energy and strong anisotropy of the turbulence.The vortex is still observable 130-140 degrees behind theblade. It gradually moves down from the impeller blade but thelocation in radial direction remains essentially unchanged. Theinfluence of the periodic fluctuations is examined and it isshown that the turbulence appears more isotropic when theperiodic fluctuations are not eliminated.</p><p>The solid particle concentration is low below the impellerand is high above the impeller tip. The particles diverge fromthe liquid flow mean direction, especially below the agitatorclose to the tip where the strongest turbulence is found.Periodic fluctuations in the particle concentration relate tothe variations found in the angle-resolved mean velocity andfluctuating velocity. The ratio of the maximum to the minimumconcentration is about 2.0 in the present study.</p><p>The baffles influence on the conditions in the impellerregion, and this influence can be observed on the fluid meanvelocity field, the angle-resolved velocities, the kineticenergy, and on the behavior of larger process particles. In theimpeller region the highest kinetic energies are about 15%higher upstream of the baffle than at the middle plane betweenthe baffles. The highest energy level in the middle plane isactually the lowest value and is therefore not representativewhen rotation symmetry is assumed.</p><p>Local energy dissipation rates have been investigated, andthe integration of the local energy dissipation rates overdifferent control volumes has been compared with macroscopicenergy balance calculations. The discrepancy is significant.Different reasons have been analyzed and recommendations forfurther investigation are given. I</p><p>n the outflow region there is a significant variation alsoin the direction of the instantaneous velocity, which may leadto direction bias in the case of non-spherical measurementvolume. In order to account for this direction bias, amathematical model is developed to estimate the projected areaof the measurement volume in LDA or PDA. It is shown that theprojected area variation can lead to a significant directionbias in determination of time averaged values and localparticle concentration in a highly turbulent stirred tank flow.This bias is however negligible for an orthogonal optical setup, as is used in the present study.</p><p><b>Keywords:</b>Hydrodynamics, phase-Doppler anemometer,suspension, pitched-blade turbine, anisotropy, turbulence,Reynolds stresses, trailing vortex, kinetic energy, stirredtank</p>
34

Stability analysis of partially filled tanker trucks using a finite element modeling approach

Aquaro, Matthew. January 1999 (has links)
Thesis (M.S.)--West Virginia University, 1999. / Title from document title page. Document formatted into pages; contains x, 78 p. : ill. (some col.) Includes abstract. Includes bibliographical references (p. 46-47).
35

Control of spring weed vegetation with saflufenacil

Mellendorf, Tracy 01 January 2009 (has links)
Field and greenhouse studies were conducted in 2007 and 2008 to evaluate the foliar efficacy of saflufenacil on horseweed (Conyza canadensis (L.) Cronq.). In the field, saflufenacil applied alone at the lowest rate (25 g/ha) resulted in less control than all other herbicide treatments that included saflufenacil. The addition of glyphosate to 25 g/ha of saflufenacil increased the level of control over either herbicide applied alone. However, the addition of glyphosate to 50 g/ha of saflufenacil or greater was not beneficial because saflufenacil alone provided at least 95% control. Overall, horseweed height at the time of herbicide application had very little effect on the efficacy of saflufenacil applied alone or in combination with glyphosate. Application variables can enhance the foliar activity of saflufenacil. In the greenhouse, saflufenacil combined with glyphosate provided greater control than saflufenacil applied alone on both glyphosate-susceptible and -resistant horseweed populations. Regardless of horseweed population or glyphosate, saflufenacil had greater activity when crop oil concentrate rather than nonionic surfactant was used as the adjuvant. Decreasing light level within 24 hours of herbicide application resulted in greater saflufenacil activity. Applying saflufenacil in a pH 5 spray solution resulted in greater activity than pH 7 or pH 9. Although effects from saflufenacil applied under different temperatures were evident in early timings, there were no lasting effects on the efficacy of saflufenacil. Saflufenacil had significant activity on both glyphosate-susceptible and -resistant horseweed. Under certain conditions when complete control of horseweed is not achieved, such as low application rates, large target weeds, and varying environmental conditions, application variables including glyphosate tank-mixtures, crop oil concentrate, low spray solution pH, and low light level may increase the level of horseweed control from saflufenacil.
36

Influência de uma piscicultura em tanques rede na qualidade da água do Rio São José dos Dourados no município de Ilha Solteira/SP /

Previato, Vanderlei. January 2009 (has links)
Orientador: Sérgio Luís de Carvalho / Banca: Alessandro Minillo / Banca: Cristiano Poleto / Resumo: A quantidade de água potável no mundo esta diminuindo em virtude de sua utilização para fins residenciais, agrícolas, industriais e comerciais, enquanto que a opulação mundial esta aumentando. O presente trabalho teve por objetivo proceder à avaliação da qualidade da água sofrendo influência de uma piscicultura em tanques rede no Rio São José dos Dourados no Município de Ilha Solteira. O rio São José dos Dourados nasce no município de Mirassol-SP a 587 metros de altitude, localizado a uma latitude de 20°49'09" sul e uma lontifude 49°21'16" oeste, desaguando no rio Paraná. Corta o município de Ilha Solteira e hoje esta ligado ao Tiete pelo canal de Pereira Barreto que incorporou os 400 Km do tramo norte à Hidrovia Tietê-Parana. Sua bacia é constituída de aproximadamente 35 afluentes e 25 municípios em toda a sua extensão. No seu curso normal, deságua no Rio Paraná, a uma longitude de 51°06'35" e latitude 20°38'44". A partir dos resultados do Índice de Qualidade de Águas será possível verificar os efeitos dessa atividade sobre a qualidade da agua, principalmente, em função da elevação dos fertilizantes (fósforo e nitrogênio). No presente trabalho propoe-se verificar a influência da piscicultura em tanques rede na qualidade da água do Rio São José dos Dourados, onde amostras de água foram colhidas em sete pontos, sendo dois pontos no meio do rio, sem a inflencia da psicultura, coletados durante os meses de janeiro a agosto de 2008, sendo confeccionado com este o Índice de Qualidade da Água da National Station Fundation dos Estados Unidos, adaptados pela CETESB / Abstract: Potable water availablein the world is being gradually reduced due to is use in households, commerce, agriculture and industry while global population is increasing. The main purpose of this work is to e valuate the water quality in an enviromental of the net-tank fishing culture in São José dos Dourados River in the city of Ilha Solteira. São José dos Dourados River borns in Mirassol - SP at 587m altitude, 20 9'09" sout h latitude and west longitude 49º31'16", flowing towards the Paraná river. It crosses the city of Ilha Solteira and actually is connected to Tietê River through the chanel of Pereira Barreto which added 400 km of the North opening to Tietê-Paraná waterway. Its basin is formed by approximately 35 tributaries and 25 cities in all its extension. In the normal running it recedes in Paraná River at 51º06'35" longitude and 20º38'44" latitude. As of the results of Water Quality Index it will be possible to check the effects of this activity over the water quality, mainly due to the increasing use of fertilizers (phosphorus and nitrogen). In this research, it is proposed to check the effects of the net-tank fishing culture over the water quality in São José dos Dourados River, where water samples were collected in seven different points, 2 of them in the middle river without the influence of fishing activity from January to August 2008. These samples were used to prepare the Water Quality Index of National Sanitation foundation of United Stares, adapted by CETESB / Mestre
37

Návrh uskladňovací nádrže / Design of storage tank

Nováček, Filip January 2013 (has links)
The aim of this diploma thesis is to design of storage tank for petroleum. The thesis is divided into two parts. In the first part of the work is focused on introducing the known types of storage tanks, their parts, use and benefits. The thesis also briefly summarized legislation regarding this issue. The second part is the actual design of storage tank. It was the strength calculation tanks according to EN 14 015. It was also a voltage FEM analysis of shell and tank roof. Result of work is a design drawing of the storage tank.
38

Sinkhole Lake Infiltration of Contaminants of Emerging Concern from Onsite Water Treatment Systems

Upton, Ethan A. 28 June 2019 (has links)
The advancement in synthetic chemicals commonly referred to as contaminants of emerging concern (CECs) and their application has led to an increase in environmental pollution. The use of septic tanks otherwise referred to as onsite water treatment systems (OWTS), promotes the introduction of CECs into the environment while allowing little in the way of remediation. In order to study the impacts of CECs from OWTS as they infiltrate the environment and the aquifer system, water, sediment, and vegetation samples were collected around a sinkhole lake surrounded by residential housing using OWTSs. The main question of this research project is what is the fate of CECs from OWTSs effluent within the catchment of a sinkhole lake? Liquid chromatograph mass spectrometry was used to analyze the samples for the presence of CECs. It was found that the relative quantity of CECs in the individual constituents is dependent upon 1) the hydrophobicity and polarity of the individual compound, 2) the specific sampling site, 3) the topography gradient, and 4) for vegetation the connectedness of the sample type to the sediment. The implications derived from this study can be applied in environmental engineering, urban and suburban planning, environmental monitoring, and should be considered when residents use well water as their source of potable water.
39

CFD Study of a Large Buried Tank within a Borehole Field

Kandiah, Parathy January 2014 (has links)
This work explores the impact of burying a short term thermal storage (STTS) tank within a borehole thermal energy storage (BTES, or borehole field). There is motivation to bury tanks in order to save space on ground level, as well as to improve the overall efficiency of the system by reducing heat losses from the tank. This work mainly looks to understand the impact of the lack of boreholes under the buried tank, as well as the thermal interactions between the tank and boreholes. Computational Fluid Dynamics was used to predict the transient temperature throughout the domain. The long-term performance was assessed by simulation a five year period. Examination of factors that influence the tank-borehole interactions was studied and it was determined that radial stratification of the borehole field as well as the soil properties have the largest influence in terms of increasing the efficiency of the BTES. Other factors, such as tank stratification and tank insulation have little impact and the remainder (tank aspect ratio, and alternate geometries) have some impact. / Thesis / Master of Applied Science (MASc)
40

Probabilistic Stress Analysis of Liquid Storage Tank

Khan, Khader A. 21 April 2010 (has links)
No description available.

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