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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.
21

Development of Measurement-based Time-domain Models and its Application to Wafer Level Packaging

Kim, Woopoung 02 July 2004 (has links)
In today's semiconductor-based computer and communication technology, system performance is determined primarily by two factors, namely on-chip and off-chip operating frequency. In this dissertation, time-domain measurement-based methods that enable gigabit data transmission in both the IC and package have been proposed using Time-Domain Reflectometry (TDR) equipment. For the evaluation of the time-domain measurement-based method, a wafer level package test vehicle was designed, fabricated and characterized using the proposed measurement-based methods. Electrical issues associated with gigabit data transmission using the wafer-level package test vehicle were investigated. The test vehicle consisted of two board transmission lines, one silicon transmission line, and solder bumps with 50um diameter and 100um pitch. In this dissertation, 1) the frequency-dependent characteristic impedance and propagation constant of the transmission lines were extracted from TDR measurements. 2) Non-physical RLGC models for transmission lines were developed from the transient behavior for the simulation of the extracted characteristic impedance and propagation constant. 3) the solder bumps with 50um diameter and 100um pitch were analytically modeled. Then, the effect of the assembled wafer-level package, silicon substrate and board material, and material interfaces on gigabit data transmission were discussed using the wafer-level package test vehicle. Finally, design recommendations for the wafer-level package on integrated board were proposed for gigabit data transmission in both the IC and package.
22

The Arbitrage Opportunities between Taiwan Depositary Receipt and Underlying Stocks.

Chou, Yueh-Chin 24 July 2012 (has links)
The issue of depositary receipt gets more attention in investors in recent year because of the explosion of Taiwan Depositary Receipt (hereafter, TDR) in Taiwan. The depositary receipts should equal to the value of primary listing stocks because they are represent the same value to a company. Therefore, we would discuss the price relationship between TDR and the primary listing stock it represents at first. In addition, because all the TDRs in Taiwan have the price spread (i.e. the price difference between TDRs and the primary listing stocks) with its original stocks, we discuss what the reasons to cause the price spread from a point of market segment. And we find it is because of liquidity, demand, information asymmetry, and stock price manipulation to lead to the price spread. After we takes market emotion into account, the market index has significant influence on price spread and individual investors also have a large influence on price spread. Finally, we try to find that whether the market has the arbitrage opportunity from the price spread after we consider the transaction cost. And the result shows that when TDR is in discount, it really has the arbitrage opportunity in market after we use the close price as the transaction price. Furthermore, if we use the open price in the next day as the transaction price, it still has excess return in market, but the profit will be lower than the strategy using the close price as the transaction price.
23

Time domain transmission line measurements with the speedy delivery signal

Zugelter, Joseph Zachary 14 February 2012 (has links)
The Speedy Delivery (SD) waveform does not undergo dispersion in transmission lines. The waveform was first introduced by Dr. Robert Flake in US Patent 6,441,695 B1 issued on August 27, 2002. Use of the SD waveform allows for high precision time domain measurements on transmission lines. High precision time domain reflectometry (TDR) and time domain transmission (TDT) measurements are described. An example measurement is presented. The design of the experimental apparatus is detailed. Voltage bias adjustments are made during measurements to increase the repeatability. Voltage bias adjustments are examined in detail. Efforts to produce short terminated measurements with high precision are included. A technique for performing TDR measurements with highly attenuated signals is presented with results. / text
24

Application of e-TDR to achieve precise time synchronization and controlled asynchronization of remotely located signals

Sripada, Aparna 14 January 2014 (has links)
Time Domain Reflectometer (TDR) measures the electrical length of a cable from the applied end to the location of an impedance change. An impedance change causes a portion of the applied signal to reflect back based on the value of its reflection coefficient. The time of flight (TOF) between the applied and reflected wave is computed and multiplied with previously determined signal propagation velocity to determine the location of the impedance change. We intentionally open terminate the output end of the cable which makes the reflection coefficient be maximum (=1) to measure its electrical length. Conventional TDRs designed for testing integrity of long cables use various closed pulse shaped test signals i.e. the half sine wave and the Gaussian pulse, that disperse (change shape) and change velocity while propagation along the cable. Quoting Dr. Leon Brillouin’s comments on electromagnetic energy propagation [10], “in a vacuum, all waves (e.g. frequencies) propagate at the same velocity, hence withoutdistortion, whereas in a dispersive lossy media, except for an infinitely long sinusoidal waveform, distortion will occur due to frequency dependent velocity.” This signal distortion generally degrades the accuracy of the measurement of the signal’s TOF. We discuss here an Enhanced Resolution Time Domain Reflectometer (e-TDR). The enhanced resolution is due to a newly discovered signal called SPEEDY DELIVERY (SD) by Dr. Robert Flake at The University of Texas at Austin (US PATENT 6,441,695 B1 issued in August 27, 2002). This SD signal has a propagation velocity that is a programmable constant and this signal preserves its shape during propagation through dispersive lossy media (DLM). This signal behavior allows us to use ‘e-TDR’ in applications where remotely located signals need to be synchronized or asynchronized precisely. Potential applications include signal based synchronization of devices like sensors connected in a network. Since the cable carrying data from sensors at discrete and remote locations to a collecting center have different electrical lengths, it is necessary to precisely offset the timestamp of the incoming signal from these sensors to allow accurate data fusion. Our prototype is capable of synchronizing signals 1,200 ft (~ 400 m) apart with sub-nanosecond resolution. / text
25

Methods of Measuring for Irrigation Scheduling - WHEN

Martin, Edward C. 10 1900 (has links)
Revised; Originally published: 2009 / 6 pp. / Proper irrigation management requires that growers assess their irrigation needs by taking measurements of various physical parameters. Some use sophisticated equipment while others use tried and true common sense approaches. Whichever method used, each has merits and limitations. In developing any irrigation management strategy, two questions are common: “When do I irrigate?” and “How much do I apply?” This bulletin deals with the WHEN.
26

Tecnologia da reflectometria no domínio do tempo para a medição da umidade do solo / Tecnology of the time domain reflectometry for measuring the soil humidity

Pereira, Sidney 26 July 2001 (has links)
Submitted by Marco Antônio de Ramos Chagas (mchagas@ufv.br) on 2017-02-06T17:32:00Z No. of bitstreams: 1 texto completo.pdf: 418994 bytes, checksum: 67a97a44f58b9545dffacaa45a2fda21 (MD5) / Made available in DSpace on 2017-02-06T17:32:00Z (GMT). No. of bitstreams: 1 texto completo.pdf: 418994 bytes, checksum: 67a97a44f58b9545dffacaa45a2fda21 (MD5) Previous issue date: 2001-07-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A tecnologia reflectometria no domínio do tempo (Time Domain Reflectometry – TDR), utilizada para medição de umidade do solo, consiste em determinar o valor da constante dielétrica do mesmo. Este valor é baseado no tempo de emissão/reflexão (tempo de trânsito) de um pulso eletromagnético, emitido por um gerador de pulsos, em hastes metálicas paralelas que servem como “guias de ondas”. O valor da constante dielétrica aparente será a do material entre as hastes metálicas, ou seja, a da matriz do solo. Como o solo é um sistema trifásico, tem-se que a constante dielétrica k para o ar é a unidade, para os componentes sólidos entre 2 e 4 e, para a água k é igual a 80. A constante dielétrica aparente é obtida pela relação: ka = ((c t)/(2 L)) 2 , em que c é a velocidade da luz no vácuo, t o tempo de trânsito e L o comprimento das hastes metálicas. Este estudo teve como objetivo determinar a correlação existente entre a constante dielétrica aparente e o conteúdo de água para um solo de textura argilosa e outro de textura arenosa, por meio de ajuste de modelo do tipo polinômio cúbico e comparar os resultados, obtidos por meio dessas equações, com um equipamento TDR comercial. Foi proposto um sistema TDR para medição da umidade do solo composto por: osciloscópio; gerador de pulsos eletromagnéticos; cabo coaxial de 50 Ω; cabo de antena de TV; casador de impedâncias; sondas (hastes metálicas paralelas) com comprimentos de 0,10, 0,15, 0,20, 0,25, 0,30 e 0,35 m, com dois diâmetros de hastes (d 1 = 3,2 mm e d 2 = 6,5 mm). Para o solo arenoso, o melhor ajuste ocorreu para a sonda de 0,30 m de comprimento, com diâmetro de hastes de 3,2 mm, obtendo um coeficiente de determinação ajustado R 2 de 0,954. Para o solo argiloso, o melhor ajuste ocorreu para a sonda de 0,30 m de comprimento, com diâmetro de hastes de 3,2 mm, obtendo-se um coeficiente de determinação ajustado R 2 de 0,923. Quando comparado com um equipamento TDR comercial, o sistema TDR proposto para a determinação da umidade do solo, no intervalo de umidade compreendido entre a capacidade de campo e o ponto de murcha, proporcionou melhores coeficientes de determinação para a sonda de 0,30 m, nos dois solos e comprimentos de sondas estudados. O sistema TDR proposto estimou a umidade do solo argiloso com erro médio relativo de 6,6%, para sonda de 0,30 m, enquanto que o sistema TDR comercial apresentou um erro médio relativo de 58,3%, para as mesmas condições, em que umidade real foi determinada em estufa. / The technology of the time domain reflectometry, TDR, used for measuring soil humidity, consists of determining the dielectric constant value of the soil. This value is based on the emission/reflection time (transit time) of an electromagnetic pulse emitted by a pulse generator, in paralleled metallic guides operating as " wave guides ". The value of the apparent dielectric constant will be that of the material between the metallic guides, that is, the one of the soil matrix. Since the soil is a system with three phases, the dielectric air constant, k, is said to be the unity for the solid components between 2 and 4, while for water k equals to 80. The apparent dielectric constant is obtained by the relationship: ka = ((c t)/(2 L) ) 2 , where c is the light speed on vacuum, t the transit time, and L the length of the metallic guides. This study aimed at the determination of the correlation between the apparent dielectric constant and water content for a clayish-textured soil and a sandy-textured soil as well, by adjusting the model of the cubic polynomial type, as well as to compare the results obtained by these equations with a commercial TDR equipment. To measure the soil humidity a TDR system was proposed, which consists of: osciloscope; electromagnetic pulse generator; coaxial cable of 50 Ω; TV antenna cable; impedance matching; probes (paralleled metallic guides) with 0.10, 0.15, 0.20, 0.25, 0.30 and 0.35 m lengths and two-diameter guides (d 1 = 3.2 mm and d 2 = 6.5 mm). For the sandy soil, the best adjustment was obtained with a 30 cm- long probe with 32 mm-diameter guides, then obtaining an adjusted R 2 determination coefficient of 0.954. For the clayish soil, the best adjustment was obtained with a 30 cm-long probe with a 3.2 mm-diameter guides, so obtaining an adjusted R 2 determination coefficient of 0.923. The TDR system proposed for determination of the soil humidity, within the humidity range between the field capacity and the wilting murcha point, provided the best determination coefficients for the 0.30 m probe in both soils and the studied probe lengths, compared with a commercial TDR equipment. The proposed TDR system estimated the clayish-soil humidity with relative error average of 6.6%, for the 0.30 m probe , while the commercial TDR system presented a relative error average of 58.3% for the same conditions under which the real humidity was oven-determined. / Dissertação importada do Alexandria
27

Mesure du comportement hygrothermique du pisé / Measurement of the hygrothermal behaviour of rammed earth

Chabriac, Pierre-Antoine 28 July 2014 (has links)
Les murs massifs en pisé sont connus pour leur confort d’habitation et leur capacité à réguler la température et l’humidité à l’intérieur des bâtiments. L’évolution des réglementations – notamment thermiques (RT 2012) – implique aujourd’hui d’avoir des bâtiments répondant à des critères drastiques. Or, le bâti en pisé semble, a priori, ne pas s’inscrire dans les références définies par ces règlements. Il semblerait donc qu’il faille prendre en compte d’autres critères que la simple résistance thermique pour caractériser le comportement d’un bâtiment en pisé. Les mécanismes couplés de transferts de masse et de chaleur qui ont lieu au sein d’un matériau poreux comme le pisé et qui conduisent à cette régulation naturelle sont bien connus empiriquement. Cependant, leurs mises en évidence scientifiques sont, quant à elles, plus difficiles.L’objectif de la thèse a été de développer une chaîne de mesure des transferts hydriques et thermiques dans les bâtiments en pisé afin de les observer et de les quantifier. Une habitation neuve en pisé a été étudiée en particulier durant ces trois ans. La thèse s’est alors déroulée en quatre phases :1 - Développement d’une chaine de mesure (capteurs de teneur en eau liquide, d’humidité relative, de température, de flux de chaleur). Chacun de ces capteurs a été modifié, adapté et étalonné pour résister au damage et fonctionner dans un matériau dense et contenant de l’argile ;2 - Caractérisation géotechnique, thermique et hydrique du matériau : granulométrie, densité, transferts de liquide et de vapeur, sorption, conductivité thermique, chaleur spécifique ;3 - Essais à l’échelle du mur en laboratoire dans un caisson étanche fonctionnant en double enceintes climatiques conçues au laboratoire. Quatre murs en pisé ont été équipés des capteurs développés en phase 1 ;4 - Essais à l’échelle de l’habitation : la maison référence a été équipée des mêmes capteurs durant sa construction et un monitoring des transferts a été établis pour au moins 5 ans.Les objectifs principaux étaient d’instrumenter des murs en pisé durant leur fabrication en prenant en compte l’énergie de compaction, d’avoir un étalonnage des capteurs tenant compte des variations importantes de températures in situ et, d’enregistrer sur une longue période (au moins 5 ans) les conditions hydriques et thermiques dans les murs, ainsi qu’à l’intérieur et à l’extérieur de l’habitation. Les résultats obtenus mettent en évidence les phénomènes de transferts thermiques et hydriques se produisant dans le pisé. Les résultats expérimentaux permettent d’envisager la mise au point de modélisations adaptées à la terre compactée. / Massive rammed earth walls are known for their comfort of living and their ability to regulate the temperature and humidity inside buildings. The evolution of regulations – particularly the thermal ones (RT 2012) - now involves having buildings that meet stringent criteria. However, rammed earth buildings seem not to be in accordance with the references defined by these regulations. This suggests that criteria, other than the simple thermal resistance,should be taken into account to characterize the behavior of a rammed earth building. The coupled heat and mass transfers mechanisms occurring within a porous material such as rammed earth – which lead to this natural regulation – are well known empirically. However, their set scientific evidences are more difficult. The aim of the thesis was to develop a measurement chain of water and heat transfers in rammed earth, to observe and quantify them. A new rammed earth house has been studied during these three years. The thesis was then carried out in four phases:1. Development of a measurement chain (liquid water content probes, relative humidity, temperature and heat flux sensors). Each of the sensors was modified and adapted and calibrated to resist compaction and run in a dense material and containing clay;2. Geotechnical, hydric and thermal characterization of the material: particle size distribution, density, transfer of liquid and vapor, sorption, thermal conductivity,specific heat;3. Testing in laboratory at wall scale in a sealed box working as double climatic chambers designed in the laboratory. Four rammed earth walls were equipped with sensors developed in phase 1;4. Testing at a house scale: the reference house was equipped with the same sensors during construction and monitoring of transfers has been set up for at least 5 years.The main objectives were to instrument rammed earth walls during their manufacturing taking into account the compaction energy, to have a sensor calibration taking into account significant variations of in situ temperatures and record over a long period (at least 5 years) hydric and thermal conditions in the walls, as well as inside and outside the building.The obtained results demonstrate the phenomena of heat and water transfers occurring in the walls. The experimental results allow considering the development of models adapted to compacted earth.
28

Effects of Transplant Season and Container Size on Landscape Establishment of Kalmia latifolia L.

Hanson, Anne-Marie 14 May 2002 (has links)
Mountain laurel (Kalmia latifolia L.) is relatively difficult to establish in landscapes. One experiment tested the effect of container size on the water relations of pinebark substrate embedded in field soil. Two other experiments tested the effects of transplant season and container size on landscape establishment of nursery-produced mountain laurel. Experiment one compared volumetric water content of embedded substrate of five sizes (4-L to 100-L) to adjacent field soil at two depths with time domain reflectometry (TDR) during a dry down cycle. Available water was calculated by subtracting unavailable water (estimated with pressure plates) from volumetric water content (TDR measurements). Adjacent soil contained more available water than embedded substrate. The middle depth held more water than the top. Larger pinebark substrate volumes retained higher volumetric water content than smaller volumes. The second experiment consisted of 7.6- and 19-L containers of Kalmia latifolia L. ‘Olympic Wedding’, transplanted into field soil in October or May. Larger container plants generally had lower xylem potential than smaller plants, but better visual ratings. Root growth into surrounding soil was negligible for all treatments. Leaf area was higher for spring transplants than fall transplants. Experiment three was a rhizotron study with 19-L plants, transplanted in October or May. Canopy growth of spring transplants was greater than fall transplants, but fall transplants had longer roots into the backfill. Overall, our data suggest that fall transplanting will potentially allow faster plant establishment than spring transplanting. The effect of container size on plant establishment could not be determined. / Master of Science
29

Estudo do comportamento de solo não saturado através de provas de carga em placa / Study of the behavior of an unsaturated soil through plate load tests

Costa, Yuri Daniel Jatobá 20 December 1999 (has links)
Este trabalho apresenta resultados de provas de carga em placa com monitoramento do teor de umidade e da sucção matricial do solo, realizadas a 1,5 m de profundidade em um solo não saturado e colapsível, considerado representativo da região centro-oeste do estado de São Paulo. Foram executados ensaios com e sem inundação da cava, do tipo lento (SML), rápido (QML) e misto (lento até um determinado estágio, passando a rápido a partir de então). O acompanhamento do teor de umidade e da sucção durante os ensaios foi realizado através de pesagem de amostras, com a utilização da técnica de reflectometria no domínio do tempo (TDR) e com o auxílio de tensiômetros. A partir dos dados obtidos, procedeu-se a uma análise da influência da sucção na resposta do sistema solo-placa. Foi observado que o aumento da sucção provoca um crescimento substancial da capacidade de carga do solo. Comparando-se ensaios inundados com não inundados, observou-se que o colapso do solo mostra-se mais proeminente com o aumento da sucção. Com respeito à técnica de reflectometria no domínio do tempo, a mesma demonstrou um desempenho satisfatório para medidas de teor de umidade in situ. / This work presents results of plate load tests with measurements of soil moisture content and matric suction, carried out at a 1.5 m depth in an unsaturated collapsible soil, considered as representative of the middle-west region of the state of São Paulo, Brazil. The tests were performed with and without the wetting of the pit. Three test methods were used: slow maintained load (SML), quick maintained load (QML), and mixed tests (SML up to a certain stage, switched to QML from there on). Soil moisture content and suction were measured through gravimetric determination on samples, the time domain reflectometry technique (TDR), and tensiometers. The gathered data allowed an assessment of the influence of the soil suction over the soil-plate system response. It was observed that the increase in suction causes a substantial increase in soil bearing capacity. Comparisons between wet and non-wet tests showed that soil collapse is higher when suction rises. The time domain reflectometry technique showed a promising performance with respect to in situ water content measurements.
30

Estudo do comportamento de solo não saturado através de provas de carga em placa / Study of the behavior of an unsaturated soil through plate load tests

Yuri Daniel Jatobá Costa 20 December 1999 (has links)
Este trabalho apresenta resultados de provas de carga em placa com monitoramento do teor de umidade e da sucção matricial do solo, realizadas a 1,5 m de profundidade em um solo não saturado e colapsível, considerado representativo da região centro-oeste do estado de São Paulo. Foram executados ensaios com e sem inundação da cava, do tipo lento (SML), rápido (QML) e misto (lento até um determinado estágio, passando a rápido a partir de então). O acompanhamento do teor de umidade e da sucção durante os ensaios foi realizado através de pesagem de amostras, com a utilização da técnica de reflectometria no domínio do tempo (TDR) e com o auxílio de tensiômetros. A partir dos dados obtidos, procedeu-se a uma análise da influência da sucção na resposta do sistema solo-placa. Foi observado que o aumento da sucção provoca um crescimento substancial da capacidade de carga do solo. Comparando-se ensaios inundados com não inundados, observou-se que o colapso do solo mostra-se mais proeminente com o aumento da sucção. Com respeito à técnica de reflectometria no domínio do tempo, a mesma demonstrou um desempenho satisfatório para medidas de teor de umidade in situ. / This work presents results of plate load tests with measurements of soil moisture content and matric suction, carried out at a 1.5 m depth in an unsaturated collapsible soil, considered as representative of the middle-west region of the state of São Paulo, Brazil. The tests were performed with and without the wetting of the pit. Three test methods were used: slow maintained load (SML), quick maintained load (QML), and mixed tests (SML up to a certain stage, switched to QML from there on). Soil moisture content and suction were measured through gravimetric determination on samples, the time domain reflectometry technique (TDR), and tensiometers. The gathered data allowed an assessment of the influence of the soil suction over the soil-plate system response. It was observed that the increase in suction causes a substantial increase in soil bearing capacity. Comparisons between wet and non-wet tests showed that soil collapse is higher when suction rises. The time domain reflectometry technique showed a promising performance with respect to in situ water content measurements.

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