Qualitative and Quantitative Reasoning

One goal of qualitative physics is to capture the mental models of engineers and scientists. This paper shows how Qualitative Process theory can be used to express concepts of engineering thermodynamics. This encoding provides the means to integrate qualitative and quantitative knowledge for solving textbook thermodynamics problems. These ideas have been implemented in a program called SCHISM, which analyzes thermodynamic cycles, such as gas turbine plants and steam power plants. W e describe its analysis of a sample textbook problem and discuss our plans for future work

Scaling of the Anomalous Boost in Relativistic Jet Boundary Layer

We investigate the one-dimensional interaction of a relativistic jet and an external medium. Relativistic magnetohydrodynamic simulations show an anomalous boost of the jet fluid in the boundary layer, as previously reported. We describe the boost mechanism using an ideal relativistic fluid and magnetohydrodynamic theory. The kinetic model is also examined for further understanding. Simple scaling laws for the maximum Lorentz factor are derived, and verified by the simulations.Comment: typos corrected; fortran 77/90 codes are attached; see ancillary files in the "Other formats" lin

Optimum Non Hydrocarbon Gas Injection Development Process and Ultimate Recovery Maximization.

A multi layered heterogeneous reservoir was selected for this study. The integrated reservoir characterization model and the pertinent transformed reservoir simulation history matched model were quality assured and quality checked. The development scheme was identified and selected where the pattern and completion of the wells were defined to fit the heterogeneity of the reservoir characterization model. Lateral and maximum block contact holes were investigated. The development processes studied were mainly hydrogen sulphide, carbon dioxide, nitrogen and rich hydrocarbon gas. The Water Alternating Gas/ Simultaneous Water Alternating Gas (WAG/SWAG) processes were also assured. In addition to the main gas and WAG/SWAG processes, many miscible and immiscible EOR processes were also investigated though the results are not presented but may be referred to. Field development options based on the development and processes schemes as well as reservoir management and long term business plans including phases of implementation were identified and assured. The development option that maximizes the ultimate recovery factor was evaluated and selected. The main objective of this work was to define the development process that could give a maximum ultimate recovery factor of more than 70%. This could increase the total technical reserves by 30% over the reserves based on classical water flooding reserves. It may be said that the life of the field could be extended to be almost doubled. The best technically development process that gives a maximum ultimate recovery factor of more than 70% was the H2S-WAG development process. The enriched-WAG development scheme can be designed to get an equivalent ultimate recovery factor by enriching the gas. The N2-WAG development process gives a relatively poor recovery factor. This is the lowest of all the Non-hydrocarbon Gas Injection (NHGI-WAG) development processes investigated

Characterization of blood drawn rapidly for use in blood volume expansion studies: An animal model for simulated weightlessness

It was demonstrated that up to 8ml of blood can be drawn from donar rats without significantly increasing volume and stress sensitive hormones, and thus can be used for volume expansion studies. Infusion of whole blood allows more physiological changes that can be seen with volume expansion by saline or other ionic solutions. The infusion of whole blood to induce hypervolemia may provide an improved model to study the fluid balance and control mechanisms operative in weightlessness. Blood samples were drawn as quickly as possible from femoral artery catheters chronically implanted in Sprague Dawley rats and analyzed for hematocrit, plasma sodium, potassium, osmolality, corticosterone, epinepherine, norepinephrine, and vasopressin. The levels were found to be comparable to those of normal rats

A model for the interpretation of biofouling

The formation of biofilms on heat exchange surfaces was studied using water with Pseudomonas fluorescens as a contaminant and also a mixture of these bacteria and kaolin particles. In every case increasing the fluid velocity resulted in a decrease in the final amount of deposit and in the deposition rate . The effect of the fluid velocity was interpreted using a mathematical model and it was found that cell adhesion and reproduction were the fundamental processes controlling the deposition rate . The presence of inorganic particles in the deposit enhanced the biofilm growth rate . This result was explained by the differences in the structure of the fouling layers

Three-dimensional full loop simulation of solids circulation in an interconnected fluidized bed

-D full loop CFD simulation of solids circulation is conducted in a complicated circulating-fluidized bed, which consists of a riser, a bubbling bed, a cyclone and a loop-seal. The effects of operating gas velocity, particle size and total solids inventory on the solids circulation rate are investigated based on the system pressure balance of an interconnected fluidized bed. CFD results indicate that the gas velocity in the riser plays a dominant role in controlling the solids circulation rate, whilst the gas velocity in the pot-seal influences in a narrow operating range. The solids circulation rate is strongly influenced by particle size and total solids inventory, but becomes insensitive to the operating conditions in the bubbling bed when the gas velocity is higher than the minimum fluidization velocity