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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.
451

Analysis of Fresh Water Resources at the Line Hole Well Field, San Salvador Island, the Bahamas

Russell Jr., Scot Allan 01 May 2010 (has links)
A major economic constraint in the Bahamas, and other small carbonates islands world-wide, is the lack of fresh water resources. To combat these socio-economic problems on San Salvador Island I sought to gain a more detailed understanding of the extent, behavior, and controls on the island’s fresh-water lens. DC electrical resistivity tomography and time-series geochemical data are used to study the fresh water lens at the Line Hole well field. Electrical Resistivity profiles are used to image the extent of fresh water resources. Time-series geochemical data provide information on the behavior of the fresh water resources as a function of time. The inversion models of the electrical resistivity profiles illustrate a fresh water lens less than 3 meters thick on average. The mixing zone is diffuse in nature, and substantially thicker than the fresh water lens. The geochemical results corroborate the fresh water lens dimensions predicted by the electrical resistivity model. In addition, mixed semi-diurnal and spring/neap tidal cycles are the primary control on the water level. Statistical analysis of specific conductance and temperature illustrate a positive and negative correlation with water level, respectively. Analysis of precipitation with respect to water level and geochemistry indicate low effective recharge rates during the period of study. The current state of the water resources at the Line Hole well field is strained. Despite moderate levels of freshening since the termination of pumping in December 2006; the system continues to be in a state of disequilibrium. The problem is compounded by abnormal thickening of the mixing zone due to communication of the well field with the ocean, and a limited volume of fresh water. In conclusion, the two techniques used in conjunction provide a non-invasive method of estimating fresh water resources in this type of setting. Conversely, the high RMS and L2 values for the electrical resistivity models and limited time-series data create a high level of uncertainty in the interpretation of results.
452

Ground Water Flow and Water Resources Investigation of the Auburn, Summers and Shakertown Springs Karst Ground Water Basins, Logan and Simpson Counties, Kentucky

Howcroft, William 01 December 1992 (has links)
The City of Auburn is faced with a number of problems relating to its dependency on two karst springs, Auburn and Summers Springs, to meet its water requirements. Besides being extremely vulnerable to contamination, the springs often discharge and insufficient volume of water needed for public consumption and dilution of the City’s treated wastewater. Thus the City wishes to find an additional source of water and views nearby Shakertown Spring as a possibility. The study has three main objectives: 1) delineation of the Auburn, Summers, and Shakertown Springs ground water basins, 2) determination of the volume of available water at each spring, and 3) investigation of additional potential water supplies as alternatives to the use of Shakertown Spring. A well survey and karst hydrogeological inventory, supplemented by dye tracing, were conducted to reveal water table information necessary for ground water basin delineation and construction of a potentiometric map. Water monitoring stations were constructed at the three springs, discharge measurements performed and stage monitored over a fifteen month period. The Auburn, Summers, and SHakertown Springs Karst Ground Water Basins are estimated to possess areas of 9.74, 3.49 and 19.02 square miles (25.23, 9.04, and 49.26 square kilometers) respectively. Summers Spring was found to have an estimated base flow discharge of 1 – 2 cubic feet per second (cfs) (0.03 – 0.06 cubic meters per second (cms)) and Shakertown Spring an estimated base flow discharge of 8 – 9 cfs (0.2-0.3 cms). Estimation of base flow discharge at Auburn Spring was not possible due to the location of the City’s water intake pipe at the spring head. However, a minimum discharge of .22 cfs (0.01 cms) was recorded on thirteen separate occasions during the period monitored. Five alternatives for the City of Auburn, including Shakertown Spring and two additional, though smaller, water sources are presented. The best source of water for the City must be decided with consideration of cost and need. A potentiometric map depicting ground water basins, water table contours and subsurface flow routes is presented as a tool for the City of Auburn to aid in decisions regarding its water resources.
453

Efeito letal dominante da radiacao gama de sup(60)Co em Biomphalaria glabrata (Say, 1818)

TALLARICO, LENITA de F. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:48:34Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:59Z (GMT). No. of bitstreams: 1 09247.pdf: 4937789 bytes, checksum: 5b8fd693e620f9b98224e5ae5b5dcc07 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
454

Din?mica de reprodu??o e comportamento reprodutivo de branchoneta Dendrocephalus brasiliensis Pesata, 1921 como incremento na produ??o de alimento vivo para peixes ornamentais

Lopes, Jos? Patroc?nio 21 December 2007 (has links)
Made available in DSpace on 2014-12-17T15:36:32Z (GMT). No. of bitstreams: 1 JosePL.pdf: 882497 bytes, checksum: cb18f10b1c9406dc277552138c430082 (MD5) Previous issue date: 2007-12-21 / Reproductive behavior of Dendrocephalus brasiliensis Pesta, 1921(Crustacean: Anostracan). The reproductive behavior of fresh water Anostracan has been poorly investigated in carcinology specialized literature, specifically in relation to Dendrocephlaus brasiliensis Pesta, 1921, with abundant data just about the geographical distribution of that Anostracan. The objective of this work was to know the reproductive behavior of this Anostracan, in different seasons (dry and raine). For this, ripe individuals of both sexes were collected in four pond of the of Fish farming Station of Paulo Afonso (EPPA), through monthly captures in each ponds, from December 2004 to November 2005. The type of reproduction was observed after the placing in aquariums (a) of then with males and (b) other on individually, at the nauplii phase, where they stayed for 15 days until the reproductive age. The sexual proportion was calculated through the relative frequencies of males and females, every month, for the whole collection period during 10 days. the production of cysts was related to the size of the female. The male: female ratio in the study period was 1 male:1,07 female. The proportion male:female was from 48,25% : 51,75% along the year. Concerning the type of reproduction, it was observed that this specie is characteerized by sexual reproduction / O comportamento reprodutivo de anostr?ceos de ?gua doce tem sido pouco divulgado na literatura especializada em carcinologia, especificamente em rela??o a Dendrocephlaus brasiliensis Pesta, 1921, havendo apenas dados abundantes sobre a distribui??o geogr?fica desse anostr?ceo dulciaqu?cola. O objetivo deste trabalho foi conhecer o comportamento reprodutivo deste an?straceo, em diferentes per?odos (seco e chuvoso). Para isto, foram utilizados indiv?duos maduros de ambos os sexos coletados em quatro viveiros da Esta??o de Piscicultura de Paulo Afonso (EPPA), atrav?s capturas mensais em cada viveiro, durante o per?odo de dezembro de 2004 a novembro de 2005. O tipo de reprodu??o foi observado atrav?s da coloca??o simult?nea em aqu?rios de algumas f?meas e machos, e outras individualmente a partir da fase de n?uplios, onde permaneceram por 15 dias at? a idade reprodutiva. A propor??o sexual dos indiv?duos foi calculada atrav?s das freq??ncias relativas de machos e de f?meas, a cada m?s, para todo o per?odo de coleta. Aos 10 dias, ? poss?vel a produ??o de cistos e o n?mero destes est? relacionado ao tamanho da f?mea. A rela??o macho:f?mea no per?odo de estudo foi de 1 macho para 1,07 f?mea. A propor??o macho: f?mea foi de 51,75% de f?mea para 48,25% de machos ao longo do ano. Quanto ao tipo de reprodu??o, foi observado tratar-se de reprodu??o sexuada
455

Efeito letal dominante da radiacao gama de sup(60)Co em Biomphalaria glabrata (Say, 1818)

TALLARICO, LENITA de F. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:48:34Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:59Z (GMT). No. of bitstreams: 1 09247.pdf: 4937789 bytes, checksum: 5b8fd693e620f9b98224e5ae5b5dcc07 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
456

Extraction and characterisation of colloids in waste repository leachate

Verrall, Karen Elizabeth January 1998 (has links)
Inorganic colloids are ubiquitous in environmental waters and are thought to be potential transporters of radionuclides and other toxic metals. Colloids present large surface areas to pollutants and contaminants present in waters and are therefore capable of sorbing and transporting them via groundwater and surface water movement. Much research has been and is currently being undertaken to understand more fully the stability of colloids in different water chemistries, factors which affect metal sorption onto colloids, and the processes which affect metal-colloid transport. This thesis first investigates ground water and surface water sampling and characterisation techniques for the investigation of the colloids present in and around a low-level waste repository. Samples were collected anaerobically using micro-purge low-flow methodology (MPLF) and then subjected to sequential ultrafiltration, again anaerobically. After separation into size fractions the solids were analysed for radiochemical content, colloid population and morphology. It was found that colloids were present in large numbers in the groundwaters extracted from the trench waste burial area (anaerobic environment), but in the surface drain waters (aerobic environment) colloid population was comparable t6 levels found in waters extracted from' above the trenches. There was evidence that the non-tritium activity was associated with the colloids and particulates in the trenches, but outside of the trenches the evidence was not conclusive because the activity and colloid concentrations were low. Secondly this thesis investigates the stability of inorganic colloids, mainly haematite, in the presence of humic acid, varying pH and electrolyte concentrations. The applicability of the Schulze-Hardy rule to haematite and haematitelhumic acid mixtures was investigated using photon correlation spectroscopy to measure the rate of fast and slow coagulation after the addition of mono, di and trivalent ions. It was found that humic coated colloids follow the Schulze-Hardy rule for mono and divalent cations, with the exception of copper ions. Trivalent ions do not follow the Schulze-Hardy rule because of their relatively strong complexation with humates. It was also found that the size of the ion has an effect on destabilisation, irrespective of charge.
457

Kalkulace ceny a její uplatnění v řízení podniku / Price Calculation and its Application in the Management of a Firm

Vlašínová, Petra January 2008 (has links)
In the thesis a general method of cost calculation as a means of determining the price has been used in a selected company. The influence of the method of cost calculation on company management has been analyzed. The thesis is focused on the water treatment company Slovácké vodárny a kanalizace a.s. I researched the most suitable method of calculating fresh water and waste water tariff for the company. I came to the conclusion that using the two-component form should bring the company higher profits than using the single-component form and these could be used to cover running and maintenance cost. I recommend using the two-component form.
458

Caracterização de bactérias do complexo Aeromonas isoladas de peixes de água doce e sua atividade patogênica. / Characterization and pathological activities of aeromonas bacterial complex isolated from freshwater fish.

Andréa Belém Costa 29 May 2003 (has links)
Pela utilização de métodos bioquímicos, biofísicos, de tipagem sorológica e de visualização das proteínas totais bacterianas, isolados de surubim Pseudoplatystoma corruscans, tilápia Oreochromis niloticus e pacu Piaractus mesopotamicus, foram caracterizados, identificados e sua virulência determinada. Dentre as linhagens de referência, o isolado de surubim caracterizou-se como sendo Plesiomonas shiguelloides e os demais isolados de tilápia e pacu foram identificados como Aeromonas hydrophila, todos pertencentes à família Vibrionaceae. Os isolados de tilápia e pacu caracterizaram-se como linhagens virulentas, resistentes aos antibióticos ampicilina, amoxicilina, lincomicina, novobiocina, oxacilina, penicilina, rifampicina e trimetoprim+sulfametoxazol, em ensaios de antibiograma realizados em meio YEA que evidenciaram que as linhagens isoladas de peixes são resistentes a oito das dezessete substâncias antimicrobianas testadas pelo método de difusão em disco. Essas características são compatíveis com as apresentadas pelo espécime tipo de A. hydrophila. Ambas as linhagens quando cultivadas em meio YEA compartilharam a mesma banda de aproximadamente 33,61kDa com o espécime tipo para A. hydrophila. Em meio enriquecido com glucose, a banda compartilhada entre elas teve peso molecular aproximado de 144,28kDa. Os testes de aglutinação sorológica evidenciaram nestas duas linhagens a presença de antígenos estáveis ao calor do tipo O. A técnica de dupla imunodifusão de Ouchterlony demonstrou que o antígeno preparado a partir do isolado de tilápia é a linhagem de A. hydrophila mais indicada para ser utilizada em estudos visando o desenvolvimento de uma vacina polivalente. / Bacteria isolated from surubim Pseudoplatystoma corruscans, tilapia Oreochromis niloticus e pacu Piaractus mesopotamicus, were characterized and identified by biochemical, biophysical, serology, and SDS-PAGE, and their virulence observed. The strain isolated from surubim was characterized as Plesiomonas shigelloides. The other strains isolated from tilapia and pacu were Aeromonas hydrophila. The isolated A. hydrophila strains presented virulence and resistance against the follow antibacterial substances: ampicillin, amoxicillin, lincomicin, novobiocin, oxacillin, penicillin, rifampin and trimetoprim+sulfametoxazole. Both strains when cultivated in YEA medium shared with the A. hydrophila type strain a similar protein band of 33,61kDa. In a medium supplemented with glucose, only one protein exhibiting relative molecular mass of 144.28 kDa, was shared by the type strains isolated from fish and the type strain. The serology tests revealed that all isolated strains presented heat-stable O-antigens. The Ouchterlony double-immunodiffusion showed that the antigen prepared from the tilapia strain possessed surface antigens similar to A. hydrophila type strain and the strains isolated from pacu. This suggested the possibility of development and usage of a common or polyvalent vaccine for A. hydrophila among tilapia and pacu or other freshwater fish species.
459

Hydrologic Structure and Function of Vernal Pools in South Deerfield, Massachusetts

Axthelm, Charlotte 29 October 2019 (has links)
Vernal pools are small, ephemeral wetlands lacking an inlet or outlet. These wetlands, also known as seasonal pools, are found in a wide range of biomes, and their characteristics vary based on location. While the vegetation of western U.S. pools, and amphibians of eastern U.S. pools have been extensively studied, many aspects of vernal pools have not been fully characterized. In particular, although the general seasonal wetting and drying cycle is understood qualitatively, few studies have attempted to quantify the hydrological regime of vernal pools in New England. As water level variation drives many, if not all, of the characteristics unique to these systems, more research on this aspect of vernal pool functioning is needed. The primary objective of this study was to gain a better understanding of vernal pool hydrology through the study of a complex of three pools in South Deerfield, MA. The water level in the South Deerfield pools has been monitored since 2009. For this study, the most recently recorded water year (1 October 2017 to 30 September 2018) was used to characterize the water level fluctuations in the Middle Pool. Water level was monitored manually (weekly intervals) and with pressure transducers (4-hour intervals) in permanently installed wells. The effects of precipitation and evapotranspiration on water level were quantified with a water balance analysis. This analysis also estimated changes in storage by estimated inflow from the uplands and outflow via deep seepage. Water level changes in the Middle Pool were consistent with qualitative descriptions and trends described in earlier studies in the region. We found that the countervailing effects of precipitation and evapotranspiration were the primary drivers of water level fluctuations throughout the year. However, the estimate of storage derived as a water balance residual was not representative of water level in the vernal pools. The storage estimate derived for the Middle Pool was more successful at estimating the water level during spring transition, the high water period most important to amphibian breeding.
460

Paleoenvironmental Reconstruction of Quaternary Saltville, Virginia, using Ostracode Autecology

Gause, Austin 01 August 2020 (has links)
The Saltville valley in southwestern Virginia is home to Quaternary localities containing paleontological and archaeological remains. Historically the valley has been mined for salt and the small lakes, ponds and springs along the valley floor have a brackish signature. A preliminary report on the site’s ostracode fauna suggested that the site’s water was not always saline. This study analyzed modern and Quaternary ostracodes to understand the valley’s hydrologic and chemical evolution. Sediments contained primarily freshwater species, including the environmentally sensitive Candona crogmaniana. The presence of Pelocypris tuberculatum and a new Fabaeformiscandona species throughout a vertical section spanning the latest Pleistocene and Holocene suggests that ephemeral pools were being fed by freshwater springs throughout the latest Quaternary. Climate ranges, estimated through species autecology and MOTR, reveal that the site’s mean annual temperature was between 0 - 19.1℃. Ostracode salinity tolerances suggest that the site was fresh during the sampled record.

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