A new vapor-liquid equilibrium apparatus was constructed to measure temperature, pressure, and phase compositions up to 8 MPa. Systems of CO(,2) with 2-methyl-1-pentene, 1-hexene, 1-heptene and m-xylene were studied at 303.15 K, 323.15 K, and 343.15 K. / A general method was proposed for equation of state construction. Two equations of State were constructed. Using critical temperature, critical pressure, critical compressibility factor and acentric factor, these equations can predict saturation properties of normal fluids. / The equations were extended to mixtures using van der Waals' one fluid theory, Lee-Kesler corresponding state approach and a virial-like approach. They had limited predictive abilities compared to cubic equations. / A correlation for third virial coefficients of nonpolar gases was developed. The correlation requires the knowledge of critical temperature, critical pressure and acentric factor and is applicable to mixtures of nonpolar gases including quantum gases. Predictions are in good agreement with reported experimental data.

It is recognised that atmospheric CO(_2) concentrations are increasing, with concerns raised as to the global impact continued rises may have. Plant stomatal parameters have been suggested as a means of monitoring changing CO(_2) levels. In order to assess their suitability for use, a thorough examination of leaf characteristics within a variety of surroundings was undertaken. Environments examined included both natural variations in CO(_2), which incorporated a variety of environmental influences and artificially enhanced ones where it was possible to monitor specific responses to variable CO(_2) levels. A short term study of Ranunculus ficaria, Sambucus nigra and Hedera helix revealed considerable variation in stomatal parameters, with inconsistent responses observed between and within species. These variations could not be attributed to CO(_2) changes and were assigned to a combination of other factors. R. ficaria grown in an artificial environment at ambient and elevated CO(_2) produced significant and consistent changes in stomatal parameters. Stomatal density and index were found to be reduced at elevated CO(_2) concentrations, with a decrease in guard cell dimensions. Salix herbacea, growing along a naturally reduced CO(_2) partial pressure gradient further highlighted the extent of variation in stomatal parameters in extant material within a species. No consistent stomatal trends associated with changing CO(_2) levels were observed. This inherent variation must be considered before any conclusions can be made regarding stomatal parameters obtained from fossil material. The novel application of molecular biology techniques to identify S. herbacea leaves was partially successful. However, identification of leaf macrofossils was not possible, due to the inferior preservation of DNA. However, the technique will provide a useful tool for identification if suitably preserved macrofossil fragments were available. S. herbacea leaf macrofossils revealed no consistent correlation to past changes in CO(_2) levels. The use of as an additional tool with which to monitor environmental change once again showed variation, and was not associated closely with changes in CO(_2) levels or stomatal parameters. In light of this work it would appear that the use of stomatal parameters is of limited value as a model to monitor environmental change, in the absence of information concerning other variables, and as such must be treated with caution.

No description available.

No description available.

To date, an estimated 70% of energy consumed comes from fossil fuels, such as coal, oil and natural gas. The major source of sulfur dioxide (SO2) emissions comes from combustion of these fossil fuels. Sulfur dioxide is a significant pollutant, because it and its higher oxidation product (SO3) react with moisture in the atmosphere to produce sulfuric acid. This results in acid rain, which comes back to earth and affects people, animals, and vegetation. Therefore, the governments of Canada, US and European countries are issuing stricter and stricter regulation to control SO2 emissions. In conventional SO2 removal processes, lime or limestone scrubbers are used, but they require large amounts of water and enough landfill sites to deal with the solid wastes. Previous attempts were made in our laboratory to recover SO2 adsorbed on activated carbon to produce sulfuric acid using non-aqueous solvents. Unfortunately, in this adsorption/distillation process, the SO2 recovery was low, as was the quality of sulfuric acid, that could not be marketable. The topic of this thesis was then conceived as an attempt to first recover SO2 via SO3 formation using supercritical carbon dioxide instead of water or non-aqueous flushing agents (desorption step) and then to use the recovered SO3 to produce linear alkylbenzene sulfonates (LAS), the main component of detergent. In the adsorption and oxidation experiments of this project, charcoal activated carbon (AC) was used to adsorb SO2 and to catalyze SO2 oxidation. The process started with a simulated flue gas, 3500 ppm SO2, 5% O2, balanced with N2. When the simulated flue gas passed through the activated carbon bed reactor, more than 95% of SO2 was oxidized to SO3. In the desorption process, SO3 contacted with the AC bed was removed using supercritical carbon dioxide (SCCO2) and 95% sulfur removal was achieved at appropriate operating conditions, for example, for a carbon bed preheated at 250??C for 6 h, and flushed by recycled SCCO2. The LAS production experiments consisted in reacting liquid linear alkylbenzene (LAB) with the recovered SO3 in an absorption column. Ceramic filters and glass beads were used in the absorption columns to break up the gas bubbles and increase the contact time between the gas and the liquid absorbent. When staged pressure columns were used and when LAB was heated to 40??C, nearly 95% of SO3 reacted with LAB to produce LAS.

This study deals with polyvinylamine (PVAm)-poly(vinyl alcohol) (PVA) based composite membranes incorporated with carbon nanotubes (CNTs) and molecular amines (e.g., piperazine (PZ), triethanolamine (TEA), N-methyldiethanolamine (MDEA), PZ/TEA and PZ/MDEA blends, diethylenetriamine (DETA) and triethylenetetramine (TETA)) for CO2 separation, solvent dehydration by pervaporation, and hydrogen purification. The effects of the parameters involved in the procedure of membrane formation and operating conditions on the membrane performance were investigated. Composite membranes comprising of a skin layer of PVAm-PVA incorporated with CNTs and a microporous polysulfone substrate were developed for CO2 separation from flue gas and dehydration of ethylene glycol by pervaporation. The membranes were characterized with Fourier transform infrared (FTIR), Raman spectroscopy, X-ray diffraction (XRD), contact angle measurement and water sorption uptake, using dense films of PVAm-PVA/CNTs, to determine the effects of CNTs on the intermolecular interactions, degree of crystallinity, surface hydrophilicity, and degrees of swelling of the membranes. For CO2/N2 separation, adding CNTs in the membrane was shown to enhance CO2 permeance while retaining a similar CO2/N2 selectivity; a CO2 permeance of 18.5 GPU and a CO2/N2 ideal selectivity of 64 were obtained at 0.6 MPa feed pressure. For pervaporative dehydration of ethylene glycol, the incorporation of CNTs into the membrane was shown to increase both the permeation flux and separation factor, and at 70??? a permeation flux of 146 g/(m2.h) and a separation factor of 1160 were achieved at 1 wt% water in feed using a PVAm-PVA/CNT composite membrane containing 2 wt% MWNTs. Novel facilitated transport membranes containing both PVAm as fixed carriers and various molecular amines as mobile carriers were fabricated and used for CO2 separation from N2 and H2, as well as CO2 separation from ethanol fermentation off gas. For membranes containing a single amine (i.e., PZ, DETA or TETA), the CO2 permeance increased with an increase in the amine content in the membrane until the amine content is sufficiently high, beyond which a further increase in the amine content would decrease the membrane performance. The facilitation in CO2 transport was more significant with membranes containing mixed amines (e.g., PZ/TEA and PZ/MDEA). Among all the molecular amines tested, TETA was shown to be most effective in facilitating CO2 transport in terms of CO2/N2 permselectivity. Using a PVAm-PVA/TETA composite membrane with a TETA to polymer (i.e., PVAm plus PVA) mass ratio of 150/100, a CO2 permeance of 22.6 GPU and a CO2/N2 selectivity of 86.5 were obtained at 0.6 MPa feed pressure for the removal of CO2 from flue gas, a CO2 permeance of 23.3 GPU and a CO2/H2 selectivity of 28.5 were obtained at 0.6 MPa feed pressure for CO2 separation from H2, a water vapor permeance of 16700 GPU was obtained at 25??? and 2.5 mol% water vapor concentration in the feed for dehydration of ethanol fermentation off gas.

The purpose of the study was to examine how forest harvesting affects the accumulation of carbon dioxide (CO2) and methane (CH4) under the ice-cover. Dissolved organic carbon (DOC) was hypothesized to increases post-harvest, this supplementation would in turn lead to an increased accumulation of CO2 and CH4 under the ice-cover. Four small boreal lakes, (two treatment lakes, two reference lakes) were sampled once a year during winter, under a three-year period (2012-2014). The sampling was performed using a headspace equilibration technique. During the three study years (2012-2014), the CO2 concentration increased in both the reference lakes and the harvested lakes (percentage increase; 18 % and 89 % respectively). The mean CH4-concentration in the reference lakes increased during the years 2012-2014, (2, 6, 7.5 μM). While the concentrations in the harvested lakes showed a slightly different pattern, with a peak during year 2013 which latter decreased until year 2014, (6, 12.5, 8.5 μM). The result of this study suggests that harvest in the catchment area increases the accumulation of CO2 and possible CH4 under the ice. Inflow of supersaturated surface water was found to be a more important source to the increased accumulation under ice than DOC, contradicting the previous hypothesis that DOC would be a more important factor controlling the CO2 and CH4 production. Moreover this study indicates that the dimension of the edge-zone left in connection to the inlets can be of crucial importance, possible reducing the amount of supersaturated surface water reaching the lakes.

The formation and oxidation of transition metal nitrides and carbides is reviewed and the crystal structures and types of bonding are discussed. Types of nitrides and carbides are categorized in terms of physical and chemical properties and type of bonding. The principles of sintering are summarised. Tlie theory and applications of thermal analytical techniques are reviewed. Surface area determination and estimation of average crystallite size by the BET method utilizing the adsorption of nitrogen gas at -196 X are explained along with the application of x-ray dififractometry ajid scanning electron microscopy to work in this area. In this present research selected transition metal nitrides and carbides have been oxidised in air and carbon dioxide. Activation energies have been determined for these reactions from isothennal oxidations utilizing the Arrhenius equation and from oxidations at different heating rates utilizing the Kissinger equation. Kinetic schemes for the isothermal oxidations have been proposed based on two models of the reactions, that is half order kinetics in which the rate of reaction is determined by the diffijsion of oxidising gas througli the oxide product and two-thirds order kinetics in which the reaction takes place at the surface of a spherical particle of diminishing size as the reaction pioceeds. Surface area measurements and electron microscopy have been utilized to study the ability of the product formed during the oxidations to sinter. X-ray diffractometry has been used to identify the crystal phases present in the initial nitride or carbide and in the oxidation products. The activation energies of the carbides were found to be lower than that found for the respective nitrides. At low temperatures the carbides oxidised more extensively than the respective nitrides, but at high temperatures the situation was reversed. This is explained in terms of the difference in the preexponential term of the Arrhenius equation. Tlie kinetics were found to be dependent on whether the oxide produced was structurally compatible with the remaining reactant and whether the oxide produced was able to sinter at the temperature used in the experiment.

No description available.

No description available.