The Atmospheric Chemistry Experiment (ACE) is a satellite mission for remote sensing of the Earth's atmosphere using the solar occultation technique. The primary instrument on this satellite is the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS). ACE-FTS retrievals are described with a focus on the creation of <em>a priori</em> temperature and pressure profiles. ACE-FTS measurements are then used to investigate the chemistry, transport and trends of chlorine, fluorine and water in the stratosphere, leading to an improved understanding of processes affecting both stratospheric ozone depletion and global climate change. <br /><br /> Total chlorine (Cl_TOT) in the stratosphere is determined using ACE-FTS measurements of eleven chlorine-containing species, supplemented by both other measurements and models, to determine Cl_TOT as a function of altitude in five latitude zones. All resulting Cl_TOT profiles are nearly linear, with a slight slope. Mean Cl_TOT for 2004 is determined to be 3. 65 ppbv for both the northern and southern midlatitudes (with a precision and estimated accuracy of ??0. 09 and ??0. 13 ppbv, respectively). A slightly lower value of mean Cl_TOT is determined for the tropics and slightly higher values at high latitudes. Total fluorine (F_TOT) in the stratosphere is also determined primarily from ACE-FTS measurements using a similar approach, resulting in stratospheric F_TOT profiles which are nearly linear with mean values ranging from 2. 50 to 2. 59 ppbv for each latitude zone (with a precision of 0. 04-0. 07 ppbv and an estimated accuracy of 0. 15 ppbv). The observed slopes and pattern of latitudinal variation are evidence of the beginning of a decline in global stratospheric chlorine and of the continuing increase in global stratospheric fluorine levels. <br /><br /> The abundance of water in the stratosphere is investigated for the northern hemisphere midlatitudes in 2004 using ACE-FTS measurements. Potential water is determined as [H₂O]+2[CH₄] and from [H₂O] versus [CH₄] correlations, resulting in a value of 7. 14??0. 05 ppmv, which is used to determine a value of 3. 65??0. 15 ppmv for the mean abundance of water entering the stratosphere. Both values are compared directly with historical data from the Atmospheric Trace Molecule Spectroscopy (ATMOS) instrument (1985-1994) and show a negligible change, implying that the increases observed by ATMOS and other long-term measurements from that time period have not continued. <br /><br /> The removal of stratospheric water in the Arctic vortex is investigated using ACE-FTS measurements. Using derived quantities from a meteorological data assimilation, northern hemisphere occultations from early 2004 are classified as vortex, vortex edge or extravortex. [CH₄] versus [N₂O] correlations are used to further classify the extravortex occultations as tropical, subtropical or midlatitude. Comparisons between profiles of [N₂O], [CH₄] and [H₂O] inside and outside the Arctic vortex, give estimates of upper stratospheric and lower mesospheric descent rates, indicating that descent in the winter 2004 Arctic vortex was rapid, with evidence of descent at higher altitudes than in past years. <br /><br /> The dehydration of air in the tropical tropopause layer and mechanisms for the entry of water vapor into the stratosphere are investigated by an analysis of ACE-FTS profiles of temperature, water vapor and [HDO]/[H₂O]. Month-to-month comparisons for 2004 and 2005 reveal a clear pattern of seasonal variation and a correlation between minimum temperature and maximum HDO depletion. Further interpretation indicates that the gradual dehydration mechanism accompanied by lofting of ice particles in the tropical troposphere is the most likely explanation for the observed seasonal variation and the shape of the [HDO]/[H₂O] profiles.

Research on electrochemical disinfection of municipal wastewater has been conducted at the University of New Orleans using a continuous flow electrochemical reactor connected to a direct current (DC) power supply changing its polarity and varying the electrode distance. Bacterial inactivation and chlorine production were the main parameters that were recorded. After months of research, it was determined that the electrochemical disinfection reactor is efficient and has a great potential for the future. There is no need to use chlorine and it has low operation costs. The following design recommendations for an electrochemical disinfection unit were given: A detention time of 5 +- 0.3 minutes A minimum volumetric current density of 1000 amps/m3 A minimum detention current density of 80 amps.hr/m3 The combination of the three recommended design values yielded excellent disinfection efficiencies and low chlorine production.

Siu Chi-kit. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 48-52). / Abstracts in English and Chinese. / TITLE PAGE --- p.i / THESIS COMMITTEE --- p.ii / ABSTRACT (ENGLISH) --- p.iii / (CHINESE) --- p.iv / ACKNOWLEDGEMENTS --- p.v / TABLE OF CONTENTS --- p.vi / LIST OF TABLES --- p.viii / LIST OF FIGURES --- p.ix / Chapter CHAPTER 1 --- Introduction --- p.1 / Chapter Section 1.1 --- Introduction --- p.1 / Chapter Section 1.2 --- Reaction of Chlorine Hydrolysis and Its Reverse Reaction --- p.2 / Chapter 1.2.1 --- Reaction in the Gas Phase --- p.2 / Chapter 1.2.2 --- Reaction in Aqueous Solution --- p.4 / Chapter 1.2.3 --- Reaction on Ice Surface --- p.5 / Chapter Section 1.3 --- Computational Method --- p.6 / Chapter Section 1.4 --- Study of Chemical Reaction by Constraint Molecular Dynamics --- p.8 / Chapter 1.4.1 --- Constraint Molecular Dynamics --- p.8 / Chapter 1.4.2 --- RATTLE Constraint Dynamics --- p.9 / Chapter 1.4.3 --- Free Energy of Chemical Reaction --- p.10 / Chapter 1.4.4 --- Radial Distribution Function --- p.11 / Chapter CHAPTER 2 --- "Ab initio Molecular Dynamics Study of the Reaction Between HC1 and HOC1 in Gas Phase, in Aqueous Solution and on Ice Surface" --- p.12 / Chapter Section 2.1 --- Structure of the Isolated Molecules --- p.13 / Chapter Section 2.2 --- Chlorine Hydrolysis in Aqueous Solution --- p.17 / Chapter 2.2.1 --- Model --- p.17 / Chapter 2.2.2 --- Results and Discussion --- p.18 / Chapter 2.2.3 --- Conclusion --- p.31 / Chapter Section 2.3 --- Heterogeneous Reaction of HC1 and HOC1 on Ice Surface --- p.32 / Chapter 2.3.1 --- Model --- p.32 / Chapter 2.3.2 --- Results and Discussion --- p.36 / Chapter 2.3.3 --- Conclusion --- p.45 / Chapter Section 2.4 --- "Comparison of the Reaction between HC1 and HOC1 in Gas Phase, in Aqueous Solution and on Ice Surface" --- p.46 / REFERENCES --- p.48

In soils spiked with gamma-HCH & DDT, and transplanted with wheat, the differences of gamma-HCH between the rhizosphere and non-rhizosphere soils increased with time, reached the peak on 30th sampling day, and then decreased with time. In the rhizosphere and non-rhizosphere soils, pp'-DDE/SigmaDDTs, op'-DDD/SigmaDDTs and pp'-DDD/SigmaDDTs increased with time; whilst op'-DDT/SigmaDDT and pp'-DDT/SigmaDDT decreased with time. The wheat, corn and soybean rhizosphere soils differed greatly in soil properties, but it was hard to conclude the effect of crop roots on the variation in concentration of gamma-HCH, p,p'-DDE, p,p'-DDD and p,p'-DDT in the rhizosphere soils except for root accumulation and translocation. / In the control, wheat and corn rhizosphere soils, the n-hexane extracted fraction of gamma-HCH, DDE, DDD and DDT decreased with time whereas the hexane/acetone extracted fraction increased with time after the 20th sampling day. The n-hexane extracted forms were higher in the rhizosphere soils than those in the non-rhizosphere soils, while the hexane/acetone extracted forms were lower in the rhizosphere soils than in the non-rhizosphere soils. / In the wheat, corn rhizosphere soils and the control, the concentration of NO3-N showed a significant negative correlation with n-hexane extracted DDE, DDD and DDT residues and a significant positive correlation with hexane/acetone extracted residues. The concentration of ammonium nitrogen (NH4-N) showed a significant negative correlation with hexane extracted gamma-HCH, DDE, DDD and DDT residues in the control, corn and wheat rhizosphere soils: but only had significant positive correlation with the n-hexane/acetone extracted fraction in the corn rhizosphere soil. The positive correlations between the n-hexane extracted residues of the target pesticides and soil OC were seldom significant in the control, sometimes significant in the wheat rhizosphere soils, and always strong and significant in the corn rhizosphere soils. The correlation of the n-hexane/acetone extracted residues with soil OC was positive and sometimes significant in the wheat rhizosphere soils, and significant and negative in the corn rhizosphere soils. The results indicated that the concentrations of different OCPs extracted from were strongly influenced by nutritional conditions and soil organic carbon. / Organic carbon (OC), dissolved organic carbon (DOC) and cultivation period were tested to explore their potential effects on target OCPs in the rhizosphere soils. The concentration of the target OCPs in the wheat rhizosphere soils increased proportionally to soil OC, whilst the uptake of OCPs by wheat roots and further translocation to the aboveground part were inversely proportional to soil OC. DOC only showed a negative correlation with concentration of p,p'-DDE and p,p'-DDT in the corn rhizosphere soils. After a longer root-soil interaction, roots had a more significant effect on the concentration of OCPs in the rhizosphere soils closer to the root surface. / The variation of different forms of OCPs in rhizosphere soils and their relationships with nitrogen nutrients and organic carbon were studied. / Variations in concentrations of organochlorine pesticide (OCP) residues in the rhizosphere soils were evaluated using rhizoboxes. A sequential extraction method was developed to study the fractionation and extractability of OCPs in rhizosphere soils. The key findings are as follows: / Zhu Xuemei. / "September 2006." / Adviser: Kin Che Lam. / Source: Dissertation Abstracts International, Volume: 68-03, Section: B, page: 1532. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 265-288). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

One advantage of higher life-forms over less developed organisms is their ability to respond to signals from their environment with motion. This requires highly specialized contractile cells and a whole locomotion apparatus. In vertebrates, the cells responsible for movement are the skeletal muscle cells. They receive signals from the autonomic nervous system in the form of an action potential, and they contract in an appropriate manner. Calcium is a vital intracellular passenger whose role in muscular function is to initiate contraction. It is released via specific channel proteins from an internal Ca++ store, the sarcoplasmic reticulum, and triggers muscular contraction, the actual interplay of actin and myosin filaments. The step that is still not fully understood is the coupling process between arrival of an action potential and the subsequent contraction, called excitation-contraction coupling. Several theories have been proposed to explain this process. Some years ago, our laboratory introduced the hypothesis that an oxidation-reduction reaction of critical sulfhydryls associated with the Ca+t channel protein are involved in the regulation of channel gating. In an effort to understand more about the Ca++ channel gating mechanism at the molecular level, this thesis focuses on the interaction between o-phthalaldehyde, a reagent which specifically forms an isoindole derivative with the amino acids cysteine and lysine, and the Ca++ release channel complex. In this thesis, the planar lipid bilayer technique was used to study the Ca++ release channel protein from skeletal muscle sarcoplasmic reticulum at the single channel level. Utilizing this experimental technique, the direct interaction between OP A and the channel was investigated. In this study, it was shown that the interaction of o-phthalaldehyde with the channel increases the channel's open probability as well as its mean open time. Furthermore, the covalent nature of o-phthalaldehyde binding to the calcium release channel complex is shown and its inhibiting effects on chloride channels are demonstrated.

<p>Microbes have been suggested to have a strong impact on the transportation of chlorine in soils. There are speculations about environmental factors limiting microbial effect on chlorine movement and retention. For this study, a numerical hydrochemical model was built to describe microbial transformation of chlorine in a laboratory lysimeter experiment. Undisturbed soil cores used to set-up the experiment were collected from a coniferous forest soil in southeast Sweden. The lysimeters were modelled in groups depending on their different water and chloride treatments. Microbial transformation of chlorine was better described under high water residence times and high chloride loads compared to low water residence times and low chloride loads. Microbial activity was also shown to properly account for a sudden shift from net-chlorine retention to net chlorine release in most of the lysimeters. Oxygen proved to be very important in accounting for the short-term shift from chloride retention to release in all the lysimeters. Model outcome revealed that 0.02– 0.10 mg Cl- could be available per day in a coniferous soil depending on season and other soil conditions. This study shows that modeling enable a better understanding of chlorine biogeochemistry. It also confirms the speculated importance of microbial activities on chloride availability in soils.</p>

The presence of chlorine in the subcratonic lithospheric mantle (SCLM) has been evaluated by compiling the compositional data of fluid inclusions in fibrous diamonds. Chlorine associates with potassium, dissolving in water and forming a KCl-bearing brine with the Cl/(Cl+H2O) molar ratio of 0.05-0.68. To examine the effect of such a KCl-bearing brine on the melting behavior of the SCLM, we conducted experiments in the Mg2SiO4-MgSiO3-H2O and Mg2SiO4-MgSiO3-KCl-H2O systems at 5 GPa and 1100-1700C. In the Mg2SiO4-MgSiO3-H2O system, the solidus temperature of forsterite+enstatite is ~1230C. In the Mg2SiO4-MgSiO3-KCl-H2O systems with molar Cl/(Cl+H2O) ratios of 0.2, 0.4 and 0.6, the solidus temperatures are ~1430C, ~1530C and ~1580C, respectively. The increase in the temperature of the solidus demonstrates that KCl elevates the solidus of the Mg2SiO4-MgSiO3-H2O system. Therefore, KCl in the SCLM can prevent melting at the H2O-saturated solidus, and a KCl-bearing fluid can be a robust agent for mantle metasomatism.

Microbes have been suggested to have a strong impact on the transportation of chlorine in soils. There are speculations about environmental factors limiting microbial effect on chlorine movement and retention. For this study, a numerical hydrochemical model was built to describe microbial transformation of chlorine in a laboratory lysimeter experiment. Undisturbed soil cores used to set-up the experiment were collected from a coniferous forest soil in southeast Sweden. The lysimeters were modelled in groups depending on their different water and chloride treatments. Microbial transformation of chlorine was better described under high water residence times and high chloride loads compared to low water residence times and low chloride loads. Microbial activity was also shown to properly account for a sudden shift from net-chlorine retention to net chlorine release in most of the lysimeters. Oxygen proved to be very important in accounting for the short-term shift from chloride retention to release in all the lysimeters. Model outcome revealed that 0.02– 0.10 mg Cl- could be available per day in a coniferous soil depending on season and other soil conditions. This study shows that modeling enable a better understanding of chlorine biogeochemistry. It also confirms the speculated importance of microbial activities on chloride availability in soils.

Chlorine is one of most common element on earth and it is essential in every living organism, but can also cause problems in the environment. Chlorine can exist both as inorganic (Clin) and organically bound (Clorg). Earlier was the common opinion that Clorg only occurs from anthropogenic sources, but the last years, research has shown that chlorine is a part of the biogeochemical cycle and Clorg also can have natural sources. Many chlorinated substances are poisonous, so the fact that they have a natural source created attention. Fertilizations with nitrogen in forest areas have shown unexpected consequences, such as an increase leakage of nitrogen to ground and surface water. Clear-cutting is a disturbance on the ecosystem and the environment is sensitive for disturbances. Because of the fact that both chlorine and fertilization can be environmental problems and that clear-cutting is a big disturbance in the nature, this study will investigate if there are changes of organic chlorine (Clorg) in soil water after clear-cutting and if fertilization with nitrogen has any influence on the concentration of Clorg. This study was made in a forest area in Värmland, Sweden (Hagfors). Chemical analyses were made in the laboratory though measuring AOX (absorbable organic halogens). The result of this study showed that clear-cutting probably has some effect on the Clorg concentration and that nitrogen doesn’t have any influence.

The world faces problems with depleting energy resources and the harmful impact of present energy consumption patterns on the environment, and consequently on the global climate and humanity. The concerns regarding global climate change are serious and have resulted in extensive research and developments on alternative, clean energy sources. While many of the available natural energy resources are limited due to their reliability, quality, quantity and density; nuclear energy has the potential to contribute a significant share of large scale energy supply without or little contributing to climate change. Hydrogen production via thermochemical water decomposition is one of the key potential processes for direct utilization of nuclear thermal energy. Thermochemical water splitting with a copper-chlorine (Cu-Cl) cycle is a promising process that could be linked with nuclear reactors to decompose water into its constituents, oxygen and hydrogen as a net result, through intermediate copper and chlorine compounds with a net input of water and heat. The process involves a series of closed-loop chemical reactions that does not contribute to any greenhouse gas emissions into the environment. Although some preliminary technical studies of the Cu-Cl cycle have been reported and some small lab scale experiments of individual reactions in the cycle have been carried out, there is still a need to link all the sub-steps of the cycle and build a pilot plant, to facilitate eventual commercialization. Such an experimental set up of overall cycle is lacking, especially to evaluate characteristics of the complete cycle such as energy, exergy and cost effectiveness. Simulation packages, such as Aspen Plus, are useful tools to provide the system designer or operator with design, optimization and operation information before building a pilot plant. In this thesis, process analysis is performed and simulation models are developed using the Aspen Plus simulation package, based on experimental work carried out at the University of Ontario Institute of Technology (UOIT), the Argonne National Laboratory (ANL), the Atomic Energy of Canada Limited (AECL) and other sources. The energy and mass balances, stream flows and properties, the heat exchanger duties and shaft work are calculated. Heat recovery options are assessed to improve thermal management and hence overall efficiency of the Cu-Cl cycle. An integrated heat exchange network is designed to use heat from the process streams efficiently and decrease the external heat demand. The efficiency of the process, based on three, four and five-step cycles, is examined in this thesis. The thermal efficiency of the five-step thermochemical process is calculated as 44%, of the four-step process is 43% and of the three-step process is 41%, based on the lower heating value of hydrogen. Sensitivity analyses are performed to study the effects of various operating parameters on the efficiency, yield, and cost. A parametric study is conducted, and possible efficiency improvements are discussed. The manner is investigated in which exergy-related parameters can be used to minimize the cost of a Cu-Cl thermochemical cycle for hydrogen production. The iterative optimization technique presented requires a minimum of available data and provides effective assistance in optimizing thermal systems, particularly in dealing with complex systems and/or cases where conventional optimization techniques cannot be applied. The principles of thermoeconomics, as embodied in the specific exergy cost (SPECO) and exergy-cost-energy-mass (EXCEM) methods, are used here to determine changes in the design parameters of the cycle that improve the cost effectiveness of the overall system. It is found that the cost rate of exergy destruction varies between $1 and $15 per kilogram of hydrogen produced; and the exergoeconomic factor between 0.5 and 0.02 as the cost of hydrogen rises from $2.8 to $20 per kg of hydrogen produced. The hydrogen cost is inversely related to the exergoeconomic factor, plant capacity and energy/exergy efficiencies. Based on the cycle’s design parameters and conditions the hydrogen production cost is calculated as $3.8/kg hydrogen. Also, an integrated Cu-Cl cycle hydrogen production system, based on nuclear and renewable energy sources, is investigated. Nuclear and renewable energy sources are reviewed to determine the most appropriate option to couple with the Cu-Cl cycle. An environmental impact assessment is conducted and compared to the conventional methods using fossil fuels and other options. Some cost assessment studies of hydrogen production are presented for this integrated system. The results show that hydrogen production cost could drop down to as low as 2.8 $/kg. The results are expected to assist ongoing efforts to increase the economic viability of the Cu-Cl cycle, and to reduce product costs of potential commercial versions of this process. / UOIT