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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

The fluid mechanics of filters

Hildyard, M. L. January 1988 (has links)
No description available.
2

The permeability of regular porous media

Stower, G. X. M. January 1985 (has links)
No description available.
3

Laminar fluid flow through unconsolidated beds of spherical and non-spherical particles

Bish, G. M. January 1987 (has links)
No description available.
4

The stochastic treatment of solute movement through a structured clay soil

Dyson, J. S. January 1987 (has links)
No description available.
5

A study of turbulent gas-solid suspension flows in bends using laser-Doppler anemometry

Parry, Andrew John January 1991 (has links)
No description available.
6

Síťové analýzy importu zemního plynu do zemí EU

Vodová, Marta January 2011 (has links)
No description available.
7

On-Site Sampling and Determination of Aliphatic Amines in Industrial Waste Water using SPME

Alghamdi, Talal January 2011 (has links)
In any oil production company, one of the problems that is faced on a daily basis and which sometimes hinders the operation is corrosion. In the presence of dissolved oxygen in the water inside any vessel, tank, or pipeline, the oxygen attacks the steel to form iron oxides, and this result in corrosion of the steel. To prevent this, corrosion inhibitors are added to the oil and gas streams. These chemicals are based on aliphatic amines, which are soluble in water, to form a film to coat the steel and prevent it from the oxygen attacks. As a chemist in the laboratory, filming amines residuals should be monitored and optimized in order to make sure the system is protected against corrosion and that no excess chemical remains. This is classically done by lengthy liquid-liquid extraction of filming amines followed by colorimetric determination using spectrophotometry of the extract. SPME is an easy, rapid, and solvent free extraction technique which can be easily coupled with GC for separation and quantification, and is a good candidate to be used for this job. In this thesis, an introduction about corrosion problems and how to control and monitor them in the oil and gas industry will be shared, as well as a literature review about various methods used to determine amines in different matrices, followed by a description of the SPME procedure, including its theory, modes, fibers, and method development procedures. A flow-through system was used to simulate the process of flowing streams in pipelines during oil production and to provide unlimited sample volumes, which contributes iv to simplifying the calculation of the distribution constant between fiber and solution. Two different agitation methods were compared, which are stirring and sonication, in order to optimize the extraction time profiles of analytes. A method was developed to determine amines, using a flow-through system at the lowest detection limit possible. Different parameters were examined such as variation of pH, salt addition, and sand addition. It was found that the pH of the solution has to be adjusted in order to get better sensitivity for the desired analytes. Finally, in-fiber kinetic calibration was used to calculate the concentration of solutions at a short extraction time. This was possible by applying the dominant desorption approach using the same analytes as standards in the fiber. The experiment was successful in shortening the extraction time from 3 hours to 20 minutes, with less than 20% variation in concentrations between the actual and the calculated.
8

On-Site Sampling and Determination of Aliphatic Amines in Industrial Waste Water using SPME

Alghamdi, Talal January 2011 (has links)
In any oil production company, one of the problems that is faced on a daily basis and which sometimes hinders the operation is corrosion. In the presence of dissolved oxygen in the water inside any vessel, tank, or pipeline, the oxygen attacks the steel to form iron oxides, and this result in corrosion of the steel. To prevent this, corrosion inhibitors are added to the oil and gas streams. These chemicals are based on aliphatic amines, which are soluble in water, to form a film to coat the steel and prevent it from the oxygen attacks. As a chemist in the laboratory, filming amines residuals should be monitored and optimized in order to make sure the system is protected against corrosion and that no excess chemical remains. This is classically done by lengthy liquid-liquid extraction of filming amines followed by colorimetric determination using spectrophotometry of the extract. SPME is an easy, rapid, and solvent free extraction technique which can be easily coupled with GC for separation and quantification, and is a good candidate to be used for this job. In this thesis, an introduction about corrosion problems and how to control and monitor them in the oil and gas industry will be shared, as well as a literature review about various methods used to determine amines in different matrices, followed by a description of the SPME procedure, including its theory, modes, fibers, and method development procedures. A flow-through system was used to simulate the process of flowing streams in pipelines during oil production and to provide unlimited sample volumes, which contributes iv to simplifying the calculation of the distribution constant between fiber and solution. Two different agitation methods were compared, which are stirring and sonication, in order to optimize the extraction time profiles of analytes. A method was developed to determine amines, using a flow-through system at the lowest detection limit possible. Different parameters were examined such as variation of pH, salt addition, and sand addition. It was found that the pH of the solution has to be adjusted in order to get better sensitivity for the desired analytes. Finally, in-fiber kinetic calibration was used to calculate the concentration of solutions at a short extraction time. This was possible by applying the dominant desorption approach using the same analytes as standards in the fiber. The experiment was successful in shortening the extraction time from 3 hours to 20 minutes, with less than 20% variation in concentrations between the actual and the calculated.
9

Mixing in axial compressors

Li, Yan Sheng January 1990 (has links)
No description available.
10

Effect of organic carbon substrates on denitrification rates in sediment

Hollingham, Melisa January 2013 (has links)
Nitrate (NO3-) is a ubiquitous groundwater contaminant in agricultural and wastewater discharge areas. The prediction of microbial mediated NO3- removal in subsurface environments requires an understanding of the rates at which electron donors are utilized by denitrifying microbes. This study focuses specifically on the following organic carbon compounds as electron donors: glucose, acetate, adenine, cysteine and fulvic acid. Six triplicate series of flow through reactors (FTRs) containing 35 cm3 of natural, organic-poor sediment were supplied for 10 weeks with solutions containing nitrate and the individual carbon compounds, along with a no-carbon added control. The organic carbon compounds were selected to yield a range of different types of organic carbon (sugars, amino acids etc.) as well as a range of Gibbs Free Energy (???G) values when their oxidation is coupled to denitrification. The initial flow rate of the FTRs was 1 ml h-1. Once steady NO3- concentrations were reached in the outflow, the flow rate was increased to 2 ml h-1 and, subsequently, 4 ml h-1. Potential denitrification rates (RD) measured for the different carbon substrates spanned a range of 0 to 114 nmol cm-3 h-1. Fulvic acid did not induce denitrification, while acetate yielded the highest rate. The outflow solutions for FTRs supplied with adenine and cysteine contained ammonia and sulfate, respectively. These results are consistent with the molecular structure of adenine, which contains an amine group, and of cysteine, containing an amine and thiol group. The results show that the addition of C-substrates to the sediment promotes denitrification, and the rate at which it occurs are dependant on which C-substrate is provided. RD results were used to determine if the denitrification rates imposed by the different carbon substrates could be predicted using theoretical approaches such as ???GR or the nominal oxidation state of carbon (NOSC). However, predictions determined by thermodynamics alone were not significantly correlated with the observed trends in denitrification rates.

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