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You searched for subject:(tracer pulse). Showing records 1 – 3 of 3 total matches.

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North Carolina State University

1. Sharpe, Desmond. Using a Hydrologic and Storm Water Model to Predict the Movement of Water Soluble Tracers via Surface Water Runoff at the Cherry Point Marine Corps Air Station.

Degree: PhD, Biological and Agricultural Engineering, 2009, North Carolina State University

GPS and stormwater models are two extremely powerful technologies that can effectively predict the movement of rainfall runoff and soluble pollutants via surface water, when applicable correctly. Using the Cherry Point Marine Corps Air Station, North Carolina, topographic information, historical and observed rainfall datasets, streamflow measurements, subsurface conduits attributes and GPS acquired data was inserted into XPSWMM to model the downstream movement of user-defined tracer elements. The overall objective of the research was to develop a hydrologic/hydraulic model to predict pollutant movement from a spill site to subcatchment outlets on the Marine Corps Air Station at Cherry Point. Other related research objectives were to: 1) to use spatial information gathered from the GIS to construction drainage areas in efforts to estimate catchment characteristics, 2) to evaluate the results of peak outflow rates gathered from several event-based hydrologic models and to explain the evolution from lumped parameter models to process-based, rainfall-runoff simulations and 3) to generate continuous simulations for rainfall-runoff processes using a calibrated/validated version of XPSWMM and 4) to introduce the concept of using pulse tracers to estimate travel times via surface water to understand associated reaction times. Advisors/Committee Members: Dr. James Gregory, Committee Member (advisor), Dr. Devendra Amatya, Committee Co-Chair (advisor), Dr. George M. Chescheir, Committee Member (advisor), Dr. R. Wayne Skaggs, Committee Co-Chair (advisor).

Subjects/Keywords: XPSWMM; rainfall runoff; SWMM; hydrology; hydraulics; pollutant transport; pulse tracer; stormwater; GPS; ArcMap; GIS

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Sharpe, D. (2009). Using a Hydrologic and Storm Water Model to Predict the Movement of Water Soluble Tracers via Surface Water Runoff at the Cherry Point Marine Corps Air Station. (Doctoral Dissertation). North Carolina State University. Retrieved from http://www.lib.ncsu.edu/resolver/1840.16/4979

Chicago Manual of Style (16th Edition):

Sharpe, Desmond. “Using a Hydrologic and Storm Water Model to Predict the Movement of Water Soluble Tracers via Surface Water Runoff at the Cherry Point Marine Corps Air Station.” 2009. Doctoral Dissertation, North Carolina State University. Accessed May 06, 2021. http://www.lib.ncsu.edu/resolver/1840.16/4979.

MLA Handbook (7th Edition):

Sharpe, Desmond. “Using a Hydrologic and Storm Water Model to Predict the Movement of Water Soluble Tracers via Surface Water Runoff at the Cherry Point Marine Corps Air Station.” 2009. Web. 06 May 2021.

Vancouver:

Sharpe D. Using a Hydrologic and Storm Water Model to Predict the Movement of Water Soluble Tracers via Surface Water Runoff at the Cherry Point Marine Corps Air Station. [Internet] [Doctoral dissertation]. North Carolina State University; 2009. [cited 2021 May 06]. Available from: http://www.lib.ncsu.edu/resolver/1840.16/4979.

Council of Science Editors:

Sharpe D. Using a Hydrologic and Storm Water Model to Predict the Movement of Water Soluble Tracers via Surface Water Runoff at the Cherry Point Marine Corps Air Station. [Doctoral Dissertation]. North Carolina State University; 2009. Available from: http://www.lib.ncsu.edu/resolver/1840.16/4979

2. Edström, Emelie. Solvent adsorption in SFC : Adsorption of methanol under supercritical conditions.

Degree: Engineering and Chemical Sciences, 2015, Karlstad University

Chromatography is a widely used separation technique including many different modes, for example supercritical fluid chromatography (SFC) which uses a supercritical fluid as mobile phase. A supercritical fluid is achieved when a substance is subjected to a temperature and pressure above the critical point and the boundary between the liquid phase and gas phase is erased. The interest for SFC has increased in recent years, mainly for separation of chiral molecules in the pharmaceutical industry. What makes SFC interesting is that it is a quick, cost-efficient and green method. This is in part due to less organic solvent used in the mobile phase in SFC compared with liquid chromatography and that the carbon dioxide that represents the major part of the mobile phase is a by-product from other processes. In SFC modifiers, often small alcohols, are added to carbon dioxide based mobile phase in order to increase the solubility of polar compounds. In this study the adsorption of methanol to two different stationary phases; Kromasil-Diol and chiral Lux Cellulose-4 were studied. Adsorption is a phenomenon where surface interactions crate a higher density of molecules at the surface than in the bulk. The aim of this work has been to study the adsorption of modifier (methanol) to the stationary phase both to determine the extent of adsorption and the kinetics for system equilibration. These findings were then put into perspective of normal use of SFC for separation of molecules. There are a number of techniques for measuring adsorption; in this study the tracer pulse method is used. This is a pulse method where a concentration plateau is created and an isotope labelled molecule is injected. This was performed in the mobile phase composition from pure carbon dioxide to pure methanol. In addition to the tracer pulse experiments the isotope effect, the eluent flow, equilibration times for the column and retention times for a set of analytes were measured. For the Diol column no large isotope effect was observed, the method was also proved to be highly reproducible since several runs gave consistent results. Calculations based on the experimental data showed that a 6.3 Å thick layer was built up at a methanol fraction of 13% (v/v), corresponding to a monolayer. Changes of the methanol fraction below the saturation level has has greater effect on the retention factor for the analytes than at higher methanol fractions, when the monolayer was saturated. The conclusion of this is that SFC is more stable in the area where the layer has been built up. A preliminary study has been made for the chiral Lux Cellulose-4 column which was not as conclusive as for the Kromasil-Diol column. This type of column needs further studies to confirm the deviating observations and to investigate the cause for these.

Subjects/Keywords: SFC; excess adsorption isotherm; methanol; tracer pulse

…1.3.1 Pulse methods The pulse methods; the tracer pulse (TP) and the perturbation… …stationary phases and retention times for analytes. - 12 - 3 Theory ∗ With the tracer pulse… …the tracer pulse in terms of excess adsorption as: ∗ 𝑉𝑉𝑅𝑅,𝑖𝑖 = 𝑉𝑉 0 + 𝑛𝑛… …Fornstedt, and P. J. R. Sjöberg, “Development of the Tracer-Pulse Method for Adsorption Studies of… …injected molecules (the tracer peak), the mass peak created by this zone is invisible… 

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Edström, E. (2015). Solvent adsorption in SFC : Adsorption of methanol under supercritical conditions. (Thesis). Karlstad University. Retrieved from http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-35185

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Edström, Emelie. “Solvent adsorption in SFC : Adsorption of methanol under supercritical conditions.” 2015. Thesis, Karlstad University. Accessed May 06, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-35185.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Edström, Emelie. “Solvent adsorption in SFC : Adsorption of methanol under supercritical conditions.” 2015. Web. 06 May 2021.

Vancouver:

Edström E. Solvent adsorption in SFC : Adsorption of methanol under supercritical conditions. [Internet] [Thesis]. Karlstad University; 2015. [cited 2021 May 06]. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-35185.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Edström E. Solvent adsorption in SFC : Adsorption of methanol under supercritical conditions. [Thesis]. Karlstad University; 2015. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-35185

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


Queens University

3. Bayona, Luis. The Effects of In-Situ Stimulation of Natural Biofilm on Groundwater Flow and Back Diffusion in a Fractured Rock Aquifer .

Degree: Civil Engineering, 2009, Queens University

Remediation of DNAPL contaminated sites in fractured rock has proven to be very difficult. No current technology can be used to remediate such sites in a timely and economic manner due to the inherent heterogeneity of fractured rock and back diffusion of contaminants stored in the rock matrix. This study was conducted in order to evaluate the viability of biostimulation of native biofilm as a means to control flow and back diffusion at fractured rock sites. A field trial was conducted at an uncontaminated site in southern Ontario. The site is underlain by dolomites of the Lockport formation. Three major fracture zones have been identified in the study area. Two closely spaced (5.04 m) boreholes were used to isolate a fracture zone at a depth of 17 m with straddle packers. These boreholes were used to create an injection-withdrawal system with recirculation, which was used for tracer injection in order to load the rock matrix with a conservative dye tracer and to inject nutrients for 21 days in order to stimulate the growth of biofilm in the fracture. Evaluation of the ability of the biofilm to control flow through the fracture was conducted through pulse interference tests. Pulse interference tests were conducted before and after the injection of nutrients. The results from the pulse interference tests showed a maximum 65% reduction in transmissivity, which is equivalent to a 28% reduction in fracture aperture shortly after the cessation of biostimulation. In order to investigate the effect of the biofilm stimulation on matrix diffusion the rock matrix was loaded with Lissamine, a conservative fluorescent dye tracer prior to biostimulation and its concentration was monitored at injection and withdrawal wells. The effect that biostimulation had on matrix diffusion was determined by comparing field concentration measurements with a model that simulates a system unaffected by biofilm stimulation. The biostimulation lowered the concentration of tracer attributable to back diffusion at the withdrawal well by about 20% for approximately 30 days following the cessation of biostimulation. It is also thought that large amounts of tracer might have been trapped in the biofilm as it formed and was then released back into the fracture as the biofilm deteriorated.

Subjects/Keywords: Tracer Test ; Pulse Interference ; Biofilm ; Numerical Model

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Bayona, L. (2009). The Effects of In-Situ Stimulation of Natural Biofilm on Groundwater Flow and Back Diffusion in a Fractured Rock Aquifer . (Thesis). Queens University. Retrieved from http://hdl.handle.net/1974/2595

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Bayona, Luis. “The Effects of In-Situ Stimulation of Natural Biofilm on Groundwater Flow and Back Diffusion in a Fractured Rock Aquifer .” 2009. Thesis, Queens University. Accessed May 06, 2021. http://hdl.handle.net/1974/2595.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Bayona, Luis. “The Effects of In-Situ Stimulation of Natural Biofilm on Groundwater Flow and Back Diffusion in a Fractured Rock Aquifer .” 2009. Web. 06 May 2021.

Vancouver:

Bayona L. The Effects of In-Situ Stimulation of Natural Biofilm on Groundwater Flow and Back Diffusion in a Fractured Rock Aquifer . [Internet] [Thesis]. Queens University; 2009. [cited 2021 May 06]. Available from: http://hdl.handle.net/1974/2595.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Bayona L. The Effects of In-Situ Stimulation of Natural Biofilm on Groundwater Flow and Back Diffusion in a Fractured Rock Aquifer . [Thesis]. Queens University; 2009. Available from: http://hdl.handle.net/1974/2595

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

.