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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.
161

Statistical analysis of trace element distributions in rocks and soils of the Breckenridge Mining District Summit County, Colorado /

Hasenohr, Edward Joseph January 1987 (has links)
No description available.
162

Trace Metals Mobility in Soils and Availability to Plants from a Long-Term Biosolids Amended Soil

Sukkariyah, Beshr 22 January 2004 (has links)
The long-term mobility and availability of trace metals has been cited as a potential hazard by critics of EPA 503 rule governing the land application of biosolids. The purpose of this research was to investigate the long-term effects of biosolids application on trace metals distribution and mobility. A single application of aerobically digested biosolids was applied to 1.5 x 2.3 m confined plots of a Davidson clay loam (clayey, kaolinitic, thermic, Rhodic Paleudult) in 1984 at 0, 42, 84, 126, 168, and 210 Mg/ha. The highest biosolids application supplied 4.5, 760, 43, and 620 kg ha-1 of Cd, Cu, Ni, and Zn, respectively. Radish (Raphanus sativus L.), lettuce (Lactuca sativa Var longifolia) and barley (Hordeum vulgare) were planted at the site. Soils were sampled to a depth of 0.9 m and sectioned into 5 cm increments after separating the Ap horizon. Total (EPA 3050B), available (Mehlich-I), sequential extraction, and dispersible clay analyses were performed on samples from the control, 126 Mg/ha and 210 Mg/ha treatments. Extractable (0.005 DTPA, 0.01 M CaCl2, and Mehlich-1) Cd, Cu, Ni, and Zn were measured on 15 cm-depth samples from each plot. Simple linear regression between plant metal concentration and biosolids-added trace metals were computed to determine uptake coefficients (UC) of crops for each metal as outlined by USEPA Part 503 Rule. Results indicated that more than 80% of the applied Cu and Zn are still found in the topsoil where biosolids were incorporated with slight enrichment down to 0.3 m. Biosolids application increased the concentration of trace metals in all the extracted fractions, with a large proportion of Zn and Cd present in the available forms. The major portion of Cu, Zn and Ni was associated with the metal-oxides fraction. Biosolids treatments had no significant effect on the yield of the crops. Plant uptake of trace metals differed among crops. Plant tissue metal concentrations increased with biosolids rate but were within the normal range for these crops. Trace metals concentration in plants generally correlated well with their concentrations extracted with 0.005 M DTPA, 0.01 M CaCl2 and Mehlich-1. Mehlich-1 gave the highest correlation coefficients for Cu and Zn and, therefore, was the most reliable in predicting their availability and uptake by the crops grown. Availability of trace metals as measured by Mehlich-I, DTPA, and CaCl2 extraction were higher in amended plots as compared to the control and increased linearly in response to biosolids addition. Metal concentration in the plants exhibited a plateau response in most cases. Several linear increases were observed in some cases in 2003 when the soil pH decreased below 5.5. The uptake coefficients values generated for the different crops were in agreement with the values set by the Part 503 Rule. / Ph. D.
163

MPIOR: A Framework to Analyze File System Performance of MPI Applications

Banerjee, Shankha 11 April 2012 (has links)
MPI I/O replay (MPIOR) is an I/O performance modeling and prediction tool used to trace and replay a parallel application to determine application performance under a new I/O sub system. The trace collector deduces synchronization inter-dependencies between nodes and I/O demands placed by each node on the storage subsystem. It uses a novel runtime graph traversal technique to filter and log only those MPI calls that affect I/O, thus substantially reducing both the number of runs and the size of the trace file. Unlike other such tools, MPIOR collects a valid trace in a single run and it does not rely on node sampling or I/O sampling. MPIOR's post processing engine analyzes the trace files and sets up the re-player. Due to minimal overhead for trace collection, MPIOR can be used during production runs rather than just as a debugging tool. The re-player mimics the behavior of the application across a variety of storage systems by mapping multiple processes to multiple threads running on a single node. We show average replay error for parallel applications is below 30%. / Master of Science
164

Characterizing Trace Element Associations in the Pittsburgh No. 8, Illinois No. 6 and Coalburg Coal Seams

Conaway, Shawn Michael 04 February 2002 (has links)
Coal preparation is widely regarded as a cost effective method for reducing the amounts of potentially hazardous air pollutant precursors (HAPPs) that occur as trace elements in the run-of-mine coals. Unfortunately, many existing coal preparation plants are inefficient in removing trace elements because of poor circuit design and inadequate liberation of coal and mineral matter. These problems are often difficult to correct in the absence of characterization data regarding the mineralogical association and washability of trace elements in run-of-mine coals. Therefore, the first step in removing the trace elements through coal preparation is to characterize the modes of association for trace elements in a coal seam. The purpose of this project was to link the occurrence of specific trace elements to the mineralogy and washability characteristics of different eastern U.S. coal seams. Detailed characterization studies were carried out using scanning electron microscopy (SEM) coupled with automated image analysis (AIA) to establish the association between different trace elements and the various components contained in coal. The first step in this analysis required the preparation of 11 different density fractions from a run-of-mine sample of 65 x 100 mesh Pittsburgh No. 8 coal. The samples were then examined using the scanning electron microscope (SEM) to establish the individual mineral constituents contained within each gravity fraction. For comparison, each gravity fraction was also carefully analyzed for trace element content by atomic adsorption spectroscopy (AA). The contribution of various mineral components to the trace element concentrations was determined in the present work using statistical procedures, i.e., individual linear regression and multiple linear regression. After completing the SEM analyses, washability (float-sink) tests were performed on three different coal seams. In this work, several size fractions from each of three different run-of-mine coals were subjected to float-sink testing and release analysis. Because of the overwhelming amount of data, statistical analyses were conducted to show the key relationships identified by this work. The data collected from this study show that trace elements are primarily associated with the mineral matter present in run-of-mine coal. The washability work also shows that the trace elements are concentrated in the heavier specific gravity classes. The characterization work shows that majority of the trace elements are associated with the ash-forming mineral matter and pyrite. The only element found to have a strong association with organic matter was beryllium. The information obtained from this work suggests that a properly designed coal preparation plant can remove substantial amounts of trace elements prior to coal combustion. / Master of Science
165

Pėdsakai įvykio vietoje: suradimas, fiksavimas, paėmimas / Trace evidences at the crime scene: locating, fixation and recovery

Nedveckytė, Jovita 24 February 2010 (has links)
Magistro baigiamajame darbe nagrinėjama ganėtinai svarbi ir aktuali tema „Pėdsakai įvykio vietoje: suradimas, fiksavimas, paėmimas“. Svarbi todėl, kad, turint omenyje dabartinę ne tik Lietuvos, bet ir pasaulio ekonominę situaciją, pastebimai daugėja nusikalstamų veikų, kurios dėl įvairių technologijų ir mokslo vystymosi tampa vis sudėtingesnės ir labiau apgalvotos. Aktuali todėl, kad kiekvienas esame vienodai suinteresuoti, kad kuo daugiau tokių nusikalstamų veikų būtų išaiškinta: surastas nusikaltėlis ir būtų tinkamai už tai nubaustas. Būtent nuo šios vietos ir tampa svarbi šio baigiamojo darbo tema, kuri ir yra skirta supažindinti su pėdsakų samprata, dažniausiai įvykio vietoje randamų pėdsakų rūšimis bei pagrindinėmis taisyklėmis, kaip reikėtų tinkamai pėdsakus užfiksuoti, kad jie neprarastų pagrindinės savo vertybės − tai yra to svarbaus ir neįkainojamo įnašo į sėkmingą tyrimo baigtį. Taigi pirmojoje darbo dalyje trumpai išdėstyta, kas yra pėdsakai, ir argumentuojama, kodėl šiame baigiamajame darbe nagrinėjamos iš esmės dvi pagrindinės pėdsakų rūšys: rankų pėdsakai bei biologiniai pėdsakai. Toliau nagrinėjant šių dviejų pėdsakų rūšių suradimo, paėmimo bei užfiksavimo subtilybes pateikiama nemažai vaizdinės medžiagos. Antroje darbo dalyje pateikta nemažai statistinių duomenų apie užregistruotas nusikalstamas veikas, apie atliktas apžiūras bei kiek buvo paimta pėdsakų ir kokia iš to buvo gauta nauda. Nagrinėjant statistinius duomenis paaiškėja pėdsakų rezultatyvumo... [toliau žr. visą tekstą] / In this master‘s thesis a quite sensitive and topical subject – Trace evidences at the crime scene: locating, fixation and recovery were analized. The criminal situation is getting worse everyday because of economical decline and andvanced technologies that are involved in commiting crime. That is why this topic is so sensitive. All of us are interested in finding and punishing criminal, regardless whether we were affected somehow by the crimes or not. And that is why this subject is so relevant. In this master’s thesis you can find the describtion of the trace evidences’ concept, the kinds of most discovered trace evidences are the main rules how correctly fixate and not to lose traces (this part is the most important to make the whole investigation successful). Why trace evidences were chosen and why only two particular kinds of them (biological and fingerptints) are being analyzed? The first part of the master’s thesis will answer these questions. Also you will find the pictures, which visually depict the beforementioned matter. We can see the statistical information about registered criminal activities, carried out inspections and the amount of taken trace evidences in the second part of master’s thesis. While analyzing this statistical information it’s became obvious why the traces which are being found in the places of the crimes are tend to become less and less informative. In the second part of thesis you can also find the answer how the legal acts of the Republic of... [to full text]
166

Bioavailability of trace metals to plants

Voigt, Astrid January 2003 (has links)
Soil quality guidelines are currently based on total trace metal loads. There is a need to define indices of bioavailability to allow reasonable predictions for plant metal uptake and toxicity in soils. Trace metal toxicities to plants often correlate best with free metal ion activities. The first objective was to develop a plant bioassay that is sensitive to trace metals at concentrations realistic for soils. The root elongation of lettuce Lactuca sativa 'Buttercrunch' was used as toxicological endpoint. This endpoint was sensitive and reproducible to environmentally relevant concentrations of Cd, Cu, Ni, Pb and Zn. The second objective was to test whether free metal ion activities are constant predictors of metal toxicities in synthetic solutions and in soil extracts that differ in their concentrations of cations and ligands. The root elongation assay was used to test this hypothesis. In synthetic solutions, the rhizotoxicity of Cd, Cu, Ni, Pb and Zn decreased with increasing Ca and H concentrations. This could not be explained with the effect of higher cationic concentrations on root growth or on solution speciation. It was concluded that Ca and H inhibited the rhizotoxicity of all metals tested. The rhizotoxicity of Cu and Cd was further examined in soil extracts. Both metals became less rhizotoxic at higher H and dissolved organic matter concentrations. The rhizotoxicity endpoints from the experiments in synthetic solution were used to develop parameters for a Biotic Ligand Model (BLM) for Cd, Cu, Ni, Pb and Zn. The BLM accounts for solution speciation and interprets cationic inhibition of rhizotoxicity as competition of metals with Ca and H for potential sites of rhizotoxicity. The BLM predicted metal rhizotoxicity better than the free metal ion activity in synthetic solutions and in soil extracts. Different models were tested against literature rhizotoxicity data for metals at different Ca and H concentrations. Predictions for metal rhizotoxicity given by BLM, Gouy-Chapman-Stern model and Freundlich equation model were compared with predictions based on free metal ion activities in solution. The BLM predicted rhizotoxicity most accurately. The BLM seems promising for predictions of metal toxicity and metal bioavailability in soils to support site-specific environmental risk assessments.
167

Studies on the preconcentration of mercury in natural waters: Electrothermal atomization of mercury from a gold surface for measurement by atomic absorption spectroscopy.

Thomson, Paul Albert. Corsini, A. Unknown Date (has links)
Thesis (Ph. D.)--McMaster University (Canada), 1989. / Source: Dissertation Abstracts International, Volume: 62-13, Section: A, page: 0000.
168

The spectrochemical determination of certain minor trace elements in plant material

Eve, Desmond John January 1961 (has links)
A study has been made of three organic complexing reagents , namely dithizone, oxine and cupferron with a view to developing suitable methods for the separation and concentration of Zn, Co, Ni, Pb, Cu, Mn, Ti , V and Mo prior to the spectrometric determination of their concentrations. In particular the influence of pH on the chloroform extraction of ditihizonates, oxinates and cupferrates from aqueous tartrate and citrate solutions and the separation of iron by oxine extraction has been investigated. The development of a method for the chemical concentration and spectrcgraphic determination of Zn, Co, Ni, Pb, Ti, V and Mo is described and the possibility of determining Nn and Cu flame photometrically as part of the analysis scheme is demonstrated. A specially designed slide rule for the calculation of spectrographic results is described. A direct reading spectrometric method for the determination of Zn, Pb and Cu in plant material is presented. The analysis of plant ash for zinc using the 2138 . 6A spectrum line has been studied and a simple, rapid analysis method is described.
169

Execution Trace Visualization for Java Pathfinder using Trace Compass / Visualisering av exekveringstrådar för Java Pathfinder med Trace Compass

Zhou, Yang January 2020 (has links)
Multi-threading is commonly applied in modern computer programs, bringing many conveniences but also causing concurrency issues. Among the various error debugging tools, Java Pathfinder (JPF) can detect latent errors of multithreaded Java programs through model checking. However, the text-based format of the output trace is hard to read, and previous attempts in visualizing JPF traces show limitations. For long-term development, popular trace analytic platform such as Trace Compass (TC) is extended to adapt to JPF traces. In this thesis, the development of JPF and TC makes it possible to analyze JPF traces on TC with a user interface including visual diagrams. The development solves the conceptual differences between the tools and successfully visualize important trace data. The implementation can help provide a generic approach for analyzing JPF traces with visualization. / Multitrådning används ofta i moderna datorprogram, vilket har många fördelar men kan också orsaka samtidighetsproblem. Bland olika felsökningsverktyg kan Java Pathfinder (JPF) upptäcka latenta fel hos multitrådade Javaprogram genom modellkontroll. Spårningsinformationen i form av text har låg läsbarhet, och tidigare försök att visualsera JPF-spår har visat begränsningar. För långsiktig utveckling har populära spårningsanalysplattformar som Trace Compass (TC) utvidgats för att anpassas till JPF-spår. I examensprojektet gör utvecklingen av JPF och TC det möjligt att analysera JPF-spår på TC med ett användargränssnitt baserat på visuella diagram. Utvecklingen löser den konceptuella skillnaden mellan verktygen och visualiserar spårdata på ett framgångsrikt sätt. Implementeringen bidrar med ett generiskt tillvägagångssätt för att analysera JPF spår med hjälp av visualisering.
170

Bioavailability of trace metals to plants

Voigt, Astrid January 2003 (has links)
No description available.

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