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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.
261

Selective CO Adsorption Separation from CO2 via Cu-modified Adsorbents

Abbassi, Maria 18 May 2021 (has links)
CO2 capture and conversion appears to be a prominent solution to mitigate greenhouse gas emissions (GHG) and global warming issue. Among different CO2 conversion approaches, CO2 hydrogenation via reverse water gas shift (RWGS) reaction is one of the most promising technology to convert CO2 to CO. Subsequently, CO is transformed to value added chemicals or liquid fuels. To improve the overall CO2 conversion for RWGS reaction, product separation and recycling is being proposed. In this research, adsorption separation technology has been explored to selectively separate CO from CO2 in RWGS using pressure swing adsorption (PSA) process. To investigate the adsorption capacity and selectivity of CO, different porous materials have been identified for CO separation. In this research, activated carbons, ordered mesoporous silica, and metal organic framework materials were studied. Equilibrium isotherms of CO and CO2 were measured in a gravimetric system at a temperature of 25 °C for pressures up to 20 bar. Preliminary adsorption isotherm results had shown an insufficient CO uptake and low selectivity level compared to CO2, thus not justifying their application for CO separation. Herein, to improve the CO adsorption capacity and selectivity, Cu-based adsorbents were developed using copper (II) chloride (CuCl2) as a precursor to synthesize six different adsorbents. The adsorbents were prepared using two different synthesis methods; the modified polyol method for reduction and nanoparticle deposition of Cu (I) ions, and thermal monolayer auto-dispersion method. Furthermore, different copper (II) loadings were investigated to determine the monolayer dispersion capacity of CuCl2 on the support. The modified adsorbents by copper salt exhibited significantly high CO uptake with large CO/CO2 selectivity, reversing the results obtained before adsorbent modification. Thus, Cubased adsorbents are promising materials for CO separation and recovery from a gaseous mixture containing CO2.
262

Road Salt Deicers as Contaminants in the Environment:

Battifarano, Oriana January 2020 (has links)
Thesis advisor: Rudolph Hon / Over 10 million tons of deicers are applied on impervious surfaces during winter storms in the United States every year to create safer driving and walking conditions. Road salt, or sodium chloride, is the most common deicer due to its low price and wide availability. Increasing concentrations of sodium chloride (NaCl) over the past decades have been measured in surface waters and groundwater throughout North America and it is projected to continue increasing. As there are no cost effective alternatives available to road salt, its potential role as an environmental and drinking water contaminant needs to be investigated. Field measurements from previous studies reveal the homogenization of NaCl in the subsurface through consistent elevated levels year-round. Through the integration of field and laboratory methods, this thesis aims to investigate the role of subsurface processes in the transport and pathways of deicers from the point of deposition to eventual emergence in surface waters and its potential impact on drinking water supplies. To understand the contamination pathways of NaCl that result in the observed surface water concentrations, experimental simulations were designed that indicate that gravitational/convective processes are the most important initial processes influencing deicer transport, but that other processes such as diffusion, surface tension, and dispersion/advection also play important roles. / Thesis (MS) — Boston College, 2020. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Earth and Environmental Sciences.
263

Measuring Acute Effects of Aluminum Chloride Exposures on the Adult Male Rat Hippocampus Using Neuro-electrophysiology and Biochemical Assays

Ethridge, Victoria Taryn 11 June 2019 (has links)
No description available.
264

Examining the effect of pH on the structure and stability of CLIC1 with E228L and E85L CLIC1 variants

Cross, Megan Olivia 01 August 2013 (has links)
A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science. Johannesburg, 2013 / The chloride intracellular channel CLIC1 is an anion channel protein that has been implicated in a number of physiological processes. It is fascinating in that it is synthesised as a soluble monomer that is able to reversibly bind membranes without the aid of a membrane-targeting tag or receptor. CLIC1 membrane binding is promoted by low pH and involves separation of the N- and C-domains and subsequent refolding of the N-domain, which traverses the membrane as an α-helix. At the low pH of a membrane surface, pH 5.5, soluble CLIC1 demonstrates decreased conformational stability and forms a partially unfolded intermediate state under mild denaturing conditions. In this study, these pH-effects are proposed to occur as a result of low pH-induced protonation of two conserved glutamate residues, Glu85 and Glu228. Both are involved in domain-maintaining interactions and are proposed to form part of an electrostatic network of pH-sensitive residues. At low pH, protonation of these glutamates would break their electrostatic interactions, allowing separation of the domains. To investigate this possibility, Glu228 and Glu85 were mutated to leucine residues. Each variant protein was then investigated at pH 7.0 and pH 5.5 and results were compared to the wild-type. Secondary and tertiary structures were examined using far-UV circular dichroism and fluorescence spectroscopy, respectively. Conformational flexibility was investigated with limited thermolysin proteolysis. Stability was studied using thermal and urea-induced equilibrium unfolding. The unfolding intermediate state was detected using ANS binding and its structure was characterised. While neither residue substitution caused global structural perturbations, both destabilised the structure and promoted intermediate formation at pH 5.5. This was particularly evident for the E85L variant, which also formed a significant intermediate population at pH 7.0. It was concluded that the interactions of Glu228 and Glu85 are involved in maintaining the CLIC1 native state. Additionally, the lack of pH-dependence of intermediate formation in the E85L variant suggested that Glu85 is likely to function as a pH-sensor. It is thus involved in the „priming‟ of the CLIC1 structure for the conformational changes that may lead to membrane binding.
265

Effect of strain cross, gender, and sodium chloride concentrations on broiler meat quality

Lopez, Keyla 06 August 2011 (has links)
Effects of gender and strain cross on carcass characteristics, meat quality and sensory acceptability were studied. Strains consisted of a commercially available strain (Strain A), and a strain genetically selected to maximize breast yield currently in the test phase (Strain B). Broilers varying in gender and strain cross had similar compositional characteristics; all treatments yielded high quality breast and thigh meat and did not differ in sensory acceptability. Effect of salt concentrations on yields, instrumental quality, and sensory acceptability of broiler breast meat was determined. Breast fillets were vacuum-tumbled with different concentrations (0, 0.25, 0.50, 0.75, 1.00, 1.25 and 1.50%) of NaCl and 0.35% sodium tripolyphosphate (STP). Marination showed improvent in CIE L*, shear force, and cooking loss. Marinated samples were highly acceptable to the majority of consumers. Results indicate that 0.5-1.0 % NaCl could be used to effectively marinate broiler breast meat depending on product application and desired attributes.
266

The removal of color-causing organic substances from low alkalinity waters by coagulation with heavy metal hydrolyzing compounds.

Beaudry, Jean-Paul January 1973 (has links)
No description available.
267

Thermal degradation of poly (vinyl chloride).

Gupta, Ved Prakash. January 1970 (has links)
No description available.
268

Microstructure and kinetics of thermal degradation of alkene copolymers of vinyl chloride

Ramacieri, Patricia. January 1986 (has links)
No description available.
269

The effects of CaCl2 and aqueous seaweed extract foliar sprays on spider mite predator/prey status and on several aspects of fruit quality of 'McIntosh' apple trees.

Coli, William M. 01 January 1980 (has links) (PDF)
No description available.
270

The Role of the Halides as Addition Agents During the Electrodeposition of Copper

MacArthur, Donald Morley 05 1900 (has links)
<p> The amount of chloride ion incorporated into a copper electrodeposit prepared from an aqueous copper sulphate solution has been determined at low chloride concentrations by the use of radiotracers. It has been found that the electrodeposits have a surface layer which is enriched in chloride ion. Evidence has been obtained that incorporation of chloride is preceded by the formation of cuprous chloride. The incorporation of chloride has been found to be increased by the presence of organic additives in the solution. The polarization during the first 30 seconds of electolysis has been interpreted using the knowledge obtained from the radiotracer work.</p> / Thesis / Doctor of Philosophy (PhD)

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