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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.
1

Study on Wave Field with Caisson on Multiple Porous Layers

Chou, Chun-ting 07 September 2010 (has links)
In the study, wave reflection, transmission, and energy dissipation with a caisson-type breakwater have been investigated experimentally. Three different sizes of grain are used to construct the porous base, they are 16mm, 25mm, and 35mm, respectively.Single and double layers of porous base are considered. Hydraulic test, porous media choice is glass ball.Wave conditions must be consistent with the scope of the linear wave theory. Two different depths are used to construct,they are 40 cm and 72 cm. Do a single trial of all size. Double size 16mm and 35mm diameter glass ball is a test. Recording the test process, and then analyze energy consumption. Water area's characteristics and pore area's characteristics are calculated by the Newton¡¦s method and the Ward¡¦s method. It is the substitute for the dispersion equation is also correct. During the course of a series, the draft of caisson is deeper, the convergence is harder. But the increase and decrease the mode number or the draft, and sometimes increase the possible of convergence. As the number of cutting layer are more complex than other predecessors, particularly in the large number of required mode, when the composition of the matrix of boundary conditions greater complexity. In the caisson area calculated pore velocity, or on behalf of the later is very large, so it's easy in the solution process, generate positive infinity or negative infinity error. As the caisson-type breakwater with a shorter wavelength, the frictional resistance influences bigger. At this time, reflectance and transmittance has the Drop tendency.When the wavelength is longer, the frictional resistance influences smaller. Most of the energy reflection because the caisson of less permeable. The caisson-type breakwater got the wave force to increase. The effect is bad in the Wave force reduced. If the static water surface above the pore structure, the caisson-type breakwater can be reduction of about 30% to 40% off the energy. If the static water surface under the pore structure, the caisson-type breakwater wave damping efficiency is better. Usually remove 30% to 70% energy. Sometimes, it¡¦s up to about 90%.Reflectivity of the caisson breakwater is larger, but the transmissivity is lower. For the waters behind the breakwater, the protective effect is significant. Transmissivity trend is arranged according to media size. As the media size smaller, the transmissivity is smaller, the reflectivity is higher. At the same depth, double-size model compared with other single-size model of the wave forces reduced is better. Whether long or short period, double-size model's performance is relatively stable. Except to a long cycle time, the wave damping efficiency has a larger range. Other cycles are at the lower position.
2

Characteristics of solar radiation transmission into a double-walled acrylic pellet-insulated greenhouse

He, Lan January 1987 (has links)
No description available.
3

esearch of the Transmission Performance and Transmission Advantage of Coupler-Driven Linkage Mechanisms

Hsu, Su-mon 19 July 2002 (has links)
This article is based on several nouns about transmission performance such as limiting positions, manipulation angle, transmission angle and mechanical advantage. In order to analyse the transmission performance of the coupler-driven and crank-output linkage mechanism, this article has developed an index called Transmissivity of Mechanical Advantage (TMA) for designers, besides this useful index, this article has identified a new noun as Total Transmission Coupler Point, that means after acting a force on the same direction of coupler point moving instantly, then the output force on the crank will act on it¡¦s moving direction and make the Transmissivity Index be the best as 1. For the designers of the coupler-driven linkage mechanisms, the transmission performance and the position where the force acts on involves to coupler curves very much. Based on the result of this research, the designers are able to choose the most proper coupler curves, and the best position of the coupler point would be designed. The designers are able to pick the best one among several similar coupler curves, and also they can certainly get a best range of either the length or the angle of the coupler designed when they were designing the coupler-driven type 4-bar linkage or the Stephenson¡¦s III 6-bar linkage. The applying force must change the direction all the time when a coupler-driven mechanism is driven, and it makes this type of mechanism seems to be uncommon, but it doesn¡¦t mean this kind of mechanism is not worth of application. On the other hand, the short of research about this type of mechanism makes the designers feel helpless when they were trying to analyse the transmission performance of mechanisms were designed. This article develops not only the theorem of analysis but also builds computer programs to help the designers to analyse the transmission performance quickly and correctly
4

Análise microclimática dos manguezais da Barra do Ribeira-Iguape/SP / Analysis microclimatic of mangroves in Barra of river Ribeira-Iguape / SP

Lima, Nádia Gilma Beserra de 30 July 2009 (has links)
O manguezal, definido como um ecossistema costeiro de transição entre os ambientes terrestres e marinhos caracteriza-se por ambiente salinizado e pela constante inundação causada por marés. Com destaque na área do Sistema Costeiro Cananéia Iguape, sua importância está relacionada à produção de biomassa, inserida no sistema bioenergético natural, aumentando a produtividade da zona costeira com a introdução de particulados orgânicos. Representam comunidades vegetais adaptadas a várias condicionantes físicas atuantes nas zonas costeiras, entre elas, as climáticas. Essa pesquisa objetivou analisar as variações dos atributos climáticos (temperatura do ar, umidade relativa do ar, radiação solar global, vento e pluviosidade) no manguezal, localizado na Barra do Ribeira- Iguape/SP, verificando se a variação existente está relacionada com as principais características da vegetação, mais especificamente pela presença de dossel no ambiente. Instalou-se uma torre microclimática contendo duas estações meteorológicas de forma a obter uma análise da variação dos atributos climáticos acima e abaixo do dossel de manguezal. Analisaram-se ainda as características estruturais do manguezal, visando comparar com os atributos climáticos. A presente pesquisa contribuiu para entender a variação dos atributos climáticos e sua influência na vegetação do manguezal. Verificou-se que, na escala de trabalho microclimática, os atributos do clima apresentam influência direta na distribuição espacial dessa vegetação. Além disso, as características do dossel é o principal controle para essa variação, principalmente na distribuição pluviométrica abaixo desse dossel, bem como na quantidade de radiação solar, que, consequentemente, influencia na distribuição das espécies vegetais do ambiente. / The mangrove is defined as a coastal ecosystem of transition between terrestrial and marine environments and is characterized by salinized environment and the constant flooding caused by tides. With emphasis in the area of coastal systems Cananéia - Iguape, its importance is more related to the production of biomass, inserted in the natural bioenergy system, that increases the productivity of the coastal zone with the introduction of organic particles. Represent plant communities adapted to different physical conditions in coastal areas, including the weather. This study aimed to analyze the changes of the attributes climate (air temperature, relative humidity, solar radiation, wind and rainfall) in the mangrove at the barra of Ribeira-Iguape/SP, checking if the variation is related to the main characteristics of vegetation, more specifically with the presence of the canopy at the environment. Was installed a tower containing two microclimatic weather stations to obtain an analysis of changes in climatic attributes above and below the canopy of mangrove. It was also analyzed the structural characteristics of mangrove, aiming to compare with the attributes climate. This research contributed to understanding the variation on the attributes of climate and its influence in the mangrove vegetation. It was found that, on the scale of work microclimatic, the attributes of climate have a direct influence on the spatial distribution of vegetation. Furthermore, the characteristics of the canopy are the main control for this variation, mainly in distribution of rainfall below the canopy and the amount of solar radiation, which consequently influences the distribution of plant species of the environment.
5

Estimates of the Hydraulic Parameters of Aquifers in Cache Valley, Utah and Idaho

Inkenbrandt, Paul C. 01 December 2010 (has links)
Hydraulic parameters of aquifers in Cache Valley were compiled from existing but largely unpublished data, from specific capacity data reported in well drillers' records, and from aquifer tests conducted for this study. A GIS database was also created to organize this information. A complete and thorough literature review was performed, which included obtaining unpublished aquifer test data from state and federal agencies, as well as reviewing Drinking Water Source Protection plans for each municipality in the valley. Well drillers' records were obtained from the Utah Division of Water Rights website and examined for pertinent information. Screened unit intervals from 1,314 well drillers' logs were databased and mapped. Transmissivity was estimated from specific capacity values obtained from 378 well drillers' records and keyed into a spatial database. Five pumping tests were also performed. Four of the tests were single-well tests using private domestic wells, and one was a multiple-well test using high-yield municipal wells owned and operated by Logan City. The sites selected for conducting the aquifer tests were the Stevenson well in Weston, Idaho in an unconfined alluvial aquifer; the Tomkinson well south of Newton, Utah in the confined gravels of western Cache Valley; the Henningsen well east of Paradise, Utah in the Salt Lake Formation; the Luthy well east of Cove, Utah in the Salt Lake Formation; and three Logan City, Utah wells in the principal aquifer. Drawdown data collected for each test provide clues regarding the surrounding geology, including the existence of a low permeability barrier and the possible presence of fractured material. The transmissivity and storativity of the principal aquifer, into which the Logan City wells are screened, have been estimated to be 300,000 square feet per day (ft2/day) and 0.000275, respectively. Drawdown curves from wells penetrating close to the East Cache fault display boundary effects. The GIS database shows that the principal aquifer underlies the east side of the valley between Smithfield and Hyrum, and has the highest density of wells, most of which are screened into confined unconsolidated gravels. The transmissivity is highest in the principal aquifer and decreases to the west, north and south of it.
6

Analysis of a LNAPL recovery system using LDRM in a South Texas facility

Kahraman, Ibrahim 29 October 2013 (has links)
Petroleum leakage from storage tanks, underground pipelines during exploration and production facilities is the reason of hydrocarbon migration into the groundwater. Petroleum companies use various LNAPL (Light Non-Aqueous Phase Liquids) recovery techniques to prevent lateral migration of hydrocarbon through the offsite of a facility. A petroleum refinery facility in the Gulf Coast region of South Texas was selected to evaluate ongoing LNAPL recovery system. Three analyses were carried out in this study. First, hydrogeologic conditions were determined using DGP (Diagnostic Gauge Plots). The concept of why ANT (Apparent LNAPL Thickness) is not a good metric to estimate recovery rates was explained based on hydrogeologic conditions of LNAPL. LNAPL and groundwater surface contour maps were built to have information about the direction of flow. All map illustrations were created using ArcGIS software. Well configurations were used to determine hydrogeologic condition in case of lack sufficient data for DGP. Second, LNAPL transmissivity were estimated using API (American Petroleum Institute) LNAPL Transmissivity Workbook. LNAPL condition was required in estimating LNAPL transmissivity values with API workbook, where methods of analysis are dependent of LNAPL condition. Total fluids recovery data were also used to estimate transmissivity values in the study wells. 0.08 ft2/d transmissivity value was arbitrarily chosen to determine the endpoint of recovery. Third, LNAPL recovery rates were predicted using LDRM (LNAPL Distribution and Recovery Model) for 11 recovery wells in the study region. Single phase –water- extraction method was used for LNAPL recovery under atmospheric conditions. Soil and fluid properties along with recovery system data were required for LNAPL recovery estimation. Some of these data were available from the dataset provided by oil company and some of them were estimated using API and Rosetta databases. Soil properties, radius of recovery values, and water production rates were calibrated in order to fit the LDRM recovery and transmissivity results with the actual field data. The modeled recovery rates and transmissivity values were consistent with actual data. Projections for future in a well were made. The model can be used for the endpoint of recovery projections. / text
7

Análise microclimática dos manguezais da Barra do Ribeira-Iguape/SP / Analysis microclimatic of mangroves in Barra of river Ribeira-Iguape / SP

Nádia Gilma Beserra de Lima 30 July 2009 (has links)
O manguezal, definido como um ecossistema costeiro de transição entre os ambientes terrestres e marinhos caracteriza-se por ambiente salinizado e pela constante inundação causada por marés. Com destaque na área do Sistema Costeiro Cananéia Iguape, sua importância está relacionada à produção de biomassa, inserida no sistema bioenergético natural, aumentando a produtividade da zona costeira com a introdução de particulados orgânicos. Representam comunidades vegetais adaptadas a várias condicionantes físicas atuantes nas zonas costeiras, entre elas, as climáticas. Essa pesquisa objetivou analisar as variações dos atributos climáticos (temperatura do ar, umidade relativa do ar, radiação solar global, vento e pluviosidade) no manguezal, localizado na Barra do Ribeira- Iguape/SP, verificando se a variação existente está relacionada com as principais características da vegetação, mais especificamente pela presença de dossel no ambiente. Instalou-se uma torre microclimática contendo duas estações meteorológicas de forma a obter uma análise da variação dos atributos climáticos acima e abaixo do dossel de manguezal. Analisaram-se ainda as características estruturais do manguezal, visando comparar com os atributos climáticos. A presente pesquisa contribuiu para entender a variação dos atributos climáticos e sua influência na vegetação do manguezal. Verificou-se que, na escala de trabalho microclimática, os atributos do clima apresentam influência direta na distribuição espacial dessa vegetação. Além disso, as características do dossel é o principal controle para essa variação, principalmente na distribuição pluviométrica abaixo desse dossel, bem como na quantidade de radiação solar, que, consequentemente, influencia na distribuição das espécies vegetais do ambiente. / The mangrove is defined as a coastal ecosystem of transition between terrestrial and marine environments and is characterized by salinized environment and the constant flooding caused by tides. With emphasis in the area of coastal systems Cananéia - Iguape, its importance is more related to the production of biomass, inserted in the natural bioenergy system, that increases the productivity of the coastal zone with the introduction of organic particles. Represent plant communities adapted to different physical conditions in coastal areas, including the weather. This study aimed to analyze the changes of the attributes climate (air temperature, relative humidity, solar radiation, wind and rainfall) in the mangrove at the barra of Ribeira-Iguape/SP, checking if the variation is related to the main characteristics of vegetation, more specifically with the presence of the canopy at the environment. Was installed a tower containing two microclimatic weather stations to obtain an analysis of changes in climatic attributes above and below the canopy of mangrove. It was also analyzed the structural characteristics of mangrove, aiming to compare with the attributes climate. This research contributed to understanding the variation on the attributes of climate and its influence in the mangrove vegetation. It was found that, on the scale of work microclimatic, the attributes of climate have a direct influence on the spatial distribution of vegetation. Furthermore, the characteristics of the canopy are the main control for this variation, mainly in distribution of rainfall below the canopy and the amount of solar radiation, which consequently influences the distribution of plant species of the environment.
8

Hydraulic Testing of the Big Hole Fault, Northern San Rafael Swell, Utah

Schieb, William M. 01 May 2004 (has links)
Six cross-hole packer tests were conducted at the Big Hole fault, a dip-slip normal fault in the northern San Rafael Swell of east-central Utah. Three tests were conducted at each of two locations along the fault, each location having a different total displacement. Water was injected in the footwall, hanging wall, and fault core and pressure changes were monitored in isolated intervals in the adjoining wells. Response curves were analyzed using the type curves developed by Hsieh and Neuman, and Theis, in order to evaluate the hydraulic properties of the fault and its associated damage zone. The tests were not quantitatively interpretable. Response curves were a poor match for Hsieh type curves and failed to give a positive definite hydraulic conductivity tensor. Theis analysis showed transmissivity varied over four orders of magnitude. The fault was both a barrier to and a conduit for fluid flow, indicating it was both heterogeneous and anisotropic with regard to flow. No correlation was seen between the fault displacement and the hydraulic properties of the fault. The lack of consistent results indicates a high variability in the hydraulic properties of the fault, possibility resulting from changes in fault core thickness and slip surface density over small distances. Injection testing at this intermediate scale is not an effective method in determining hydraulic properties of faults in sandstone reservoirs with deformation band style faulting.
9

Application of fluid electrical conductivity logging for fractured rock aquifer characterisation at the University of the Western Cape's Franschhoek and Rawsonville research sites

Lasher, Candice January 2011 (has links)
<p>&nbsp / Characterisation of fractured rock aquifers is important when dealing with groundwater protection and management. Fractures are often good conduits for water and contaminants, leading to high flow velocities and the fast spread of contaminants in these aquifers. A cost effective methodology is required for the characterisation of the role of individual fractures contributing to flow to boreholes in fractured rock aquifers. Literature shows that some of the conventional methods used to characterise hydraulic properties in fractured rock aquifers are expensive, complicated, time consuming and are associated with some disadvantages such as over-or under- estimations of flow rates. iii This thesis evaluates the use of Fluid Electrical Conductivity (FEC) logging in fractured rock aquifers. This FEC data are compared to various traditional methods used to determine aquifer hydraulic properties applied at the Franschhoek and Rawsonville research sites. Both these sites were drilled into the fractured rock Table Mountain Group (TMG) Aquifer, forming one of the major aquifers in South Africa.</p>
10

Hydrologic behaviour and hydraulic properties of a patterned fen in Saskatchewan

Hogan, Jaime Michele 30 January 2006
A patterned, partially-treed, fen in the mid-boreal region of central Saskatchewan was the site of renewed hydrological research from 2002 to 2004. Hydraulic conductivity, transmissivity, and storativity were determined through use of a surface loading test, pumping tests, and an enclosed field drainage test. None of these field tests have been previously described in the literature as having been used in peat environments. The combined results of field and laboratory drainage tests were used to obtain a general storativity with water table depth relationship in the upper peat layer. The hydraulic conductivity, measured with slug tests, the loading test, and pumping tests, is high near the surface, declining greatly with depth. These previously untested field methods have the advantage of representing volumes of peat from tenths of a meter to cubic meters. </p>Characterization of the hydrology of the peatland involved year round observations of water table, piezometric head, peat surface elevations, frost depth and peat temperatures. Fluctuations of the water table, and soil moisture changes produce changes in effective stress that lead to volume change in the highly compressible peat. This is particularly important for sites with thick peat deposits. Independent compressibility estimates were as high as 10-5 N/m2 in the upper peat. At three fen sites, changes in peat thickness were estimated from monthly estimates of effective stress change, using year round hydrological observations, and compared to measured annual peat thickness changes. Water table changes causing soil moisture changes, and freeze-thaw processes, explained the majority of peat surface movements.

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