Thermal–mechanical modelling around the cavities of underground coal gasification

Underground coal gasification (UCG) is an efficient method for the conversion of the deep coal resources into energy. This paper is concerned with a feasibility study of the potential of deeply lying coal seams (>1200 m) for the application of UCG combined with subsequent storage of CO2 for a site located in Bulgaria. A thermal–mechanical coupled model was developed using the ABAQUS software package to predict the heat transfer, the stress distributions around the UCG and the consequent surface subsidence. Material properties of rocks and coal were obtained from existing literature and geomechanical tests which were carried out on samples derived from the demonstration site in Bulgaria. Three days of gasification has been simulated by assigning a moving heat flux on a cell of 2 m × 2 m × 2 m at a velocity of 2 m/day. Results of temperature and stress distribution showed that the developed numerical model was able to simulate the heat propagation and the stress distribution around cavities under a thermal–mechanical coupled loading during the UCG process. Also, the surface subsidence was found to be 0.08 mm after three days of gasification for the case studied. It is anticipated that the results of this paper can be used for the prediction and optimization of the UCG process in deep coal seams

Phase Partitioning and Thermo-physical Properties of Athabasca Bitumen / Solvent Mixtures

The phase behaviour and thermo-physical properties of bitumen/solvent systems are of crucial importance for heavy oil and bitumen in-situ recovery methods as well as pipeline transportation, surface upgrading, and refining. The equilibrium properties of mixtures containing heavy oil are also important for the development of numerical simulators, the application of various thermal and non-thermal recovery processes, and the application of fluid extraction processes. The main objective of this study was the development of a comprehensive understanding of the phase behaviour of bitumen/solvent mixtures. A new pressure-volume-temperature (PVT) apparatus was designed and constructed to acquire experimental data for the phase behaviour of bitumen/solvent mixtures and their thermo-physical properties. A new methodology for phase detection and accurate volume measurements was proposed for obtaining single liquid, vapour-liquid, and liquid-liquid equilibrium properties as well as the extraction yield for bitumen/solvent systems. New vapour-liquid and liquid-liquid equilibrium data for Athabasca bitumen / ethane and Athabasca bitumen / propane mixtures were experimentally acquired and corresponding phase diagrams were generated over wide ranges of temperatures and pressures. The effect of different parameters, such as the solvent-to-oil ratio, pressure, and temperature, on equilibrium phase compositions, saturated phase properties (density and viscosity), and the distribution of fractions in different phases were studied. The optimal solvent for bitumen viscosity reduction was identified at different operating conditions. The potential applications of ethane and propane for the supercritical and subcritical extraction of valuable components from bitumen were also experimentally evaluated. The generated data were then modelled with the Peng-Robinson equation of state to accurately predict the phase boundaries and phase compositions. New measurements for thermo-physical properties of Athabasca bitumen / n-hexane and Athabasca bitumen / condensate mixtures were conducted at different temperatures, pressures, and solvent weight fractions. The mixture density and viscosity data were evaluated with predictive schemes as well as with correlation models representing certain mixing rules proposed in the literature. The influences of pressure, temperature, and solvent weight fraction on the density and viscosity of mixtures were considered in the models and evaluated from the experimental results.2 year

Characterization of Neutralizing and Non-neutralizing Epitopes of Porcine Circovirus 2 Capsid Protein

Vaccination is the most efficacious way to prevent Porcine circovirus 2 (PCV2)-associated diseases. In experimental pig studies, vaccine-induced neutralizing antibodies (NAs) appear to play a major role in protection from PCV2 infection. The immune response to PCV2 vaccination of farmed pigs has not been studied in detail. I hypothesize that NAs target conformational epitope(s) present on the surface of PCV2 particles. Highly purified PCV2 particles were found to expose only conformational but not linear epitopes on their surface. The screening 160 sera from farmed pigs showed that reactivity of sera with PCV2 particles correlated positively with the level of NA titer, suggesting that NAs recognize surface-exposed conformational epitope(s). This finding was supported by depleting antibodies reacting with linear epitopes of PCV2. No significant change was observed in the level of NA titer after antibody depletion. Altogether, these data suggest that NAs target conformational epitope(s) on the surface of PCV2 particles

An Investigation on the Effects of Method and Type of Subsoiling on Consumed Water, Yield and Quality of Cotton

Abstract\ud Compaction is applied by an external force on the soil and its result is decreasing soil macro porosity and increasing soil bulk density. One of the main important parameter in soil compaction is mechanization in agriculture and travelling in the fields. Compaction with decreasing in soil infiltration, percentage of stable aggregates and decreasing soil porosity limits the developing of roots, infiltration and decreasing of water in the soil and finally decreases crop yield. In order to study of the effect of C and L shape subsoiler on water consumption and quantitative and qualitative characteristics of cotton, an experiment was conducted in Hashem Ababd of Gorgan in silt-clay-loam soil for two years. This study carried out in split plot arrangement based on randomised complete block design with three replications. Two methods of subsoiling (parallel and perpendicular to row plant) were taken as a main plot and the form of subsoiler (L shape, C shape and moldboard as testimonial) were assigned to sub plot. C and L shape Subsoilers decrease the soil penetration resistance significantly which this decreasing was more in C shape subsoiler. the results showed that none of the treatments, subsoilers, the methods of subsoiling and their reciprocal effects, did not affect on cotton yield in the first year. However, the continuity of the second year subsoiling affected significantly the cotton yield. The C shape subsoiler in perpendicular to row plant had more cotton yield in compare with other treatments. Despite the lack of significant cotton yield increase, The use of subsoiler could be explained in economic terms with respect to the increased yield. The fibres quality was not affected by the treatments. Most water consumption in this study in first and second year was achieved by L shape subsoiler with 5740 and 4163 m3 ha-1, respectively.\ud \ud Keywords: Subsoiler, Penetration resistance, Cotton yield, Water consumptio