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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.

Rainfall estimation from satellite images

Ingraham, Diane Verna January 1980 (has links)
The design, management and operation (as well as the associated costs) of major water resource projects are directly related to the assessment of the anticipated volumes of runoff to be handled by the project. In remote or sparsely gauged regions it is often very difficult to determine these volumes due to a lack of data. The meteorological satellites, and in particular, the Geostationary Operational Environmental Satellites (GOES) can provide good areal coverage of the Earth and its weather systems potentially every half hour day and night. Since the first meteorological satellite images were transmitted, many attempts have been made to estimate rainfall using the images to identify specific cloud characteristics and correlating these with expected rainfall. However, these methods have been limited to convective rainfall in the tropics or near tropics. A method is presented here for estimating half-hourly rainfall which relates the vertical updraft velocities and hence, the moisture flux into the cloud, to the rate of vertical and horizontal growth of the cloud top as revealed in the GOES infrared images. The method performs well in estimating rainfall from widespread frontal systems common over British Columbia. A number of computational difficulties which arose during the research were resolved. One was to ascertain cloud top temperature contours for those GOES infrared images which were not enhanced. This involved the use of a video camera-special effects generator-video monitor system. The second was one of bookkeeping to "keep track of" the individual cloud cells. This was taken care of through the use of computer routines which directed the input and output of data, accounted for the growth and movement of the storm cells over the region and interpolated for rainfall at those locations which fell between adjacent precipitation contours. The method was used to estimate rainfall for a number of test storms occurring over British Columbia. The results were remarkably successful although there were some local inadequacies. An updating -procedure was developed in which the satellite estimated values of rainfall were improved by taking into consideration the information provided by concurrent rainfall observations. Furthermore, the parameters of the updating model (determined for gauged -locations) can be used to update rainfall estimates for ungauged locations. In the light of present raingauge installation and operating costs and the limitations of radar in mountainous areas, the satellite rainfall estimation procedure provides an economical operational supplement to existing conventional precipitation data collection. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

Studies of Continuous Precipitation

Palmer, Walter McKinnon January 1949 (has links)

A prototype raindrop-size distrometer and its application to Hong Kongrains

陳仲良, Chan, Chung-leung, Johnny. January 1976 (has links)
published_or_final_version / Physics / Master / Master of Philosophy

Utah local area model sensitivity to boundary conditions for summer rain simulations

DeSordi, Steven Paul. January 1996 (has links) (PDF)
Thesis (M.S.)--University of Utah, 1996. Thesis from the University of Utah's Department of Meteorology explores the sensitivity of the pecipitation-predicting model known as the Utah Limited Area Model (LAM) to the way that the lateral and upper boundary conditions are applied. The approach is different from most past studies of LAM boundary specification because it is founded upon a medium-range simulation using real data. Many other studies of boundary conditions have used idealized cases or short-term (a few days or less) predictions. / Title from web page (viewed Oct. 30, 2003). "96-084." "August 1996." Includes bibliographical references p. [110]-112. Also available in print version.

Affinity precipitation of proteins characterization of some underlying mechanisms /

Larsson, Eva Linné. January 1996 (has links)
Thesis (doctoral)--Lund University, 1996. / Added t.p. with thesis statement inserted.

Affinity precipitation of proteins characterization of some underlying mechanisms /

Larsson, Eva Linné. January 1996 (has links)
Thesis (doctoral)--Lund University, 1996. / Added t.p. with thesis statement inserted.

Verification of Satellite Derived Precipitation Estimates Over Complex Terrain: A Ground Truth Analysis for Nepal

Athey, Ashley Taylor 05 June 2015 (has links)
Precipitation estimates from the satellite-based Tropical Rainfall Measuring Mission (TRMM) instrumentation play a key role in flood analysis and water resource management across many regions of the world where rain gauge data are sparsely available. Previous studies have produced conflicting results regarding the accuracy of satellite-derived precipitation products, and several authors have called for further examination of their utility, specifically across the Himalaya Mountains region of southern Asia. In this study, daily precipitation estimates generated by TRMM were compared to daily precipitation measurements from a rain gauge network across the country of Nepal. TRMM data were statistically analyzed to quantify their representation of the gauge data during the four precipitation-defined seasons of Nepal. A detailed case study was assembled for the TRMM grid cell characterized by the greatest precipitation gauge density to develop a deeper understanding of local precipitation variability that the coarse resolution TRMM product cannot capture. The results illustrate that TRMM performs relatively well across all seasons, though the performance of TRMM during frozen precipitation events is not clear. In general, TRMM underestimates daily precipitation during the monsoon and pre-monsoon seasons, and overestimates during the winter and post-monsoon season. The case study analysis revealed a threshold for TRMM bias of 10-20mm of daily precipitation, overestimating lighter precipitation events while underestimating heavier precipitation events. Still, TRMM data compare favorably to gauge data, which contributes to the confidence with which they and other satellite-derived data products are used. / Master of Science

Comparative study and water budget of precipitation lines

Haynes, Margaret Eugene January 1974 (has links)
No description available.

Comparative study and water budget of precipitation lines

Haynes, Margaret Eugene January 1974 (has links)
No description available.

Biogenic sulfide production at low pH and selected metal precipitation for e-waste leachate treatment / Précipitation sélective des métaux à l'aide de sulfure d'origine biologique

Janyasuthiwong, Suthee 03 July 2015 (has links)
La contamination métallique dans l'environnement est l'un des problèmes mondiaux persistants car non seulement elle perturbe la qualité de l'environnement, mais aussi l'environnement et la santé humaine. La principale contribution à ce problème se pose principalement des activités anthropiques telles que les industries. La rareté de métal est devenu plus sévère récents où certains éléments ont été prédit pour être pleinement éradiquée depuis plusieurs décennies de la croûte terrestre. Récemment, des chercheurs ont concentré leur attention pour récupérer ces métaux dans le flux des déchets et de la réutiliser dans les processus de production industrielle. L'utilisation des déchets agricoles comme adsorbant potentiel à faible coût pour l'enlèvement des métaux lourds des eaux usées est une des technologies les plus polyvalents. Dans cette étude entre les différents adsorbants testés, coquille d'arachide établi rendements d'épuration élevés avec moins d'exigences pour un traitement ultérieur de poste pour le Cu, Pb et Zn retrait. En outre, les expériences de lots sur les principaux effets des paramètres du procédé (pH, adsorbant dosage, temps de contact et de la concentration initiale de métal) ont montré un effet majeur sur l'absorption des métaux et de l'efficacité de l'enlèvement. Pour la régénération matériau, HCl 0.2 M était la solution de désorption la plus efficace qui ne altère pas l'efficacité, jusqu'à trois cycles d'adsorption et de désorption. L'utilisation de bactéries réductrices de sulfate (SRB) dans des bioréacteurs est une autre technologie qui peut être appliqué pour le traitement de métal contaminé les eaux usées. Le SRB réduire le sulfate en sulfure, qui réagit en outre avec des métaux pour former des précipités de sulfures métalliques. Le lit fluidisé (IFB) bioréacteur inverse est la configuration qui présente la proéminence en utilisant la technologie de SRB pour le traitement des eaux usées métalliques contaminés. Deux bioréacteurs IFB ont été opérés à différents pH (7.0 et 5.0). L'activité de SRB à pH 7.0 était plus élevée qu'à un pH de 5.0, ce qui montre que le pH est le principal facteur qui affecte SRB. Cependant, le thiosulfate a montré une efficacité supérieure à celle du sulfate en tant qu'accepteur d'électrons alternatif. Le sulfure produit en utilisant du thiosulfate comme accepteur d'électrons était 157.0 mg / L, tandis que seulement 150.2 mg / L a été produit en utilisant du sulfate et il a fallu une période d'adaptation à un pH de 5.0 avant la réussite de l'opération. En outre, l'IFB a montré sa grande efficacité pour le Cu, Ni et Zn élimination des eaux usées synthétique. L'élimination de Cu et Zn étaient plus de 90% à pH 7.0 et 5.0, à une concentration initiale de métal de 25 mg / L. D'autre part, l'élimination de Ni ne était pas éliminé à une concentration initiale de 25 mg / L comme il a montré des effets toxiques à l'égard SRB. Il existe différents types de flux de déchets contaminés par des métaux qui se présentent comme un bon candidat pour la récupération des métaux comprennent e-déchets. Cet e-déchets a un fort potentiel en tant que source secondaire de métal pour récupérer les métaux en particulier base tels que Cu, Ni et Zn. Cartes de circuits imprimés (PCB) d'ordinateurs personnels ont été évalués comme source secondaire potentielle de Cu, Ni et Zn en utilisant des méthodes de précipitation hydrométallurgiques et de sulfure. Les conditions optimales pour la lixiviation des métaux étaient de 0.1 M HNO3 avec un rapport liquide solide de 20 à l'aide de PCB de 0.5 - taille des particules de 1.0 mm à 60 ° C qui a abouti à 400 mg Cu / g PCB. Avec la précipitation de sulfure à un rapport stoechiométrique de 1: 1 (Cu: S2-), la récupération de Cu a été très efficace jusqu'à 90% de la solution de lixiviation a représenté à environ 0.41 g Cu / g BPC, tout en Ni et Zn étaient récupération 40 % et 50% pour les lixiviats d'une colonne à courant ascendant de lixiviation, respectivement / Metal contamination in the environment is one of the persisting global issues since it not only disturbs the environmental quality but also the environment and human health. The major contribution to this problem arises mainly from anthropogenic activities such as industries. Metal scarcity has become more severe lately where some elements have been predicted to be fully eradicated in several decades from the earth crust. Recently, researchers have focused their attention to recover these metals from the waste stream and reuse it in industrial production processes. The use of agricultural wastes as a potential low cost adsorbent for heavy metal removal from wastewater is one of the most versatile technologies. In this study among the different adsorbents tested, groundnut shell established high removal efficiencies with fewer requirements for further post treatment for Cu, Pb and Zn removal. Furthermore, the batch experiments on the main effects of process parameters (pH, adsorbent dosage, contact time and initial metal concentration) showed a major effect on metal uptake and removal efficiency. For material regeneration, 0.2 M HCl was the most effective desorbing solution that did not alter the efficiency, up to three cycles of adsorption and desorption. The use of sulfate reducing bacteria (SRB) in bioreactors is another technology that can be applied for the treatment of metal contaminated wastewater. The SRB reduce sulfate into sulfide which further reacts with metals to form metal sulfide precipitates. The inverse fluidized bed (IFB) bioreactor is the configuration which shows prominence in utilizing SRB technology for metal contaminated wastewater treatment. Two IFB bioreactors were operated at different pH (7.0 and 5.0). The sulfate reducing activity (SRA) at pH 7.0 was higher than at pH 5.0, which shows that pH is the main factor that affects SRA. However, thiosulfate showed a higher efficiency than sulfate as an alternate electron acceptor. The sulfide produced using thiosulfate as the electron acceptor was 157.0 mg/L, while only 150.2 mg/L was produced using sulfate and it required an adaptation period at pH 5.0 prior to successful operation. Moreover, the IFB had shown its high efficiency for Cu, Ni and Zn removal from synthetic wastewater. The removal of Cu and Zn were more than 90% at pH 7.0 and 5.0, at an initial metal concentration of 25 mg/L. On the other hand, Ni removal was not removed at an initial concentration of 25 mg/L as it showed toxic effects toward SRB. There are various types of metal contaminated waste streams which pose as a good candidate for metal recovery include electronics waste (e-waste). This e-waste has a high potential as secondary source of metal to recover especially base metals such as Cu, Ni and Zn. Printed circuit boards (PCBs) of personal computers were evaluated as the potential secondary source of Cu, Ni and Zn using hydrometallurgical and sulfide precipitation methods. The optimal conditions for metal leaching were 0.1 M HNO3 with a liquid to solid ratio of 20 using PCBs of 0.5 - 1.0 mm particle size at 60 °C which resulted in 400 mg Cu/g PCBs. With sulfide precipitation at a stochiometric ratio of 1:1 (Cu:S2-), the recovery of Cu was very effective up to 90% from the leachate which accounted to approximately 0.41 g Cu/g PCBs, while Ni and Zn recovery were 40% (0.005 g Ni/g PCBs) and 50% (0.006 g Zn/g PCBs) for leachate from an upflow leaching column, respectively. This indicates Cu can be recovered from PCBs using sulfide precipitation

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