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Phase separation spinning of porous polypropylene hollow fibersNelson, Douglas Edmund January 1974 (has links)
Two phase separation polymer-solvent systems were studied: polypropylene-paraffin wax, and polypropylene-naphthalene. A tube-in-orifice spinneret design was used.
All attempts to spin hollow fibers using the polypropyleneparaffin wax system failed. Initial attempts to produce hollow fibers from polypropylene-naphthalene solutions resulted in fiber samples with outside diameters ranging from 60 to 297 microns, and inside diameters ranging from 15 to 90 microns. However, subsequent spinning trials resulting in unpredictable solution flow behavior through the spinneret or drastic polymer degradation. A review of spinning procedures and pertinent literature led to the conclusion that chain scission of the polymer molecules was being catalyzed by contact of the polymer with certain metals (e.g. copper and iron) during solution preparation. However, with the use of a non-metallic mixing vessel and stirrer, the use of a nitrogen atmosphere, and the addition of proper stabilizers, this problem should be prevented in future studies.
From observations made by optical and scanning electron microscopes, and mercury intrusion pore size distribution measurements, it was concluded that the structure of the fibers consisted of fine networks of interconnecting voids or pores. The significant majority of these pores had diameters of less than one micron.
Among the suggested areas for further study in the development of hollow fibers spun from polypropylene-naphthalene solutions were spinning condition effects on pore size distribution and the possibility of using a controlled temperature liquid quench bath in the spinning process. / Master of Science
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Design and construction of test apparatus for SO₂ adsorption researchNeff, Dennis Alan January 1977 (has links)
A detailed literature review investigated the major factors affecting the reduction of sulfur dioxide (SO₂) emissions to the atmosphere. As determined from this review, there is a great need for a regenerable, negligible waste, flue gas desulfurization system that can economically compete with existing, non-regenerable, considerable waste systems.
Experimental apparatus was designed and constructed for use in future investigations of the adsorption of SO₂ from a simulated flue gas, which will be used for an ultimate prototype system design. The apparatus consists of an air-drying plenum, centrifugal fan, heat exchanger, mixing/adsorbing column, exhaust unit, and devices for pressure, temperature, SO₂-concentration, and flow measurement. A detailed description of the apparatus is included.
The initial system start-up consisted of calibrating flow nozzles, and testing the performance of the drying plenum and gas chromatographic system. Flow nozzles were calibrated for air using a rotameter, and then the calibrated flow rates were compared to theoretical flow rates obtained assuming inviscid flow. Excellent agreement between the calibrated and theoretical values was observed, except at very low rotameter scale positions where the possible percentage of reading error is large. A performance test was conducted that revealed the drying plenum's ability to provide extremely dry air (less than 1 per cent H₂O by volume) for flow rates ranging from 8.8 to 35.5 std m³/hr (5.2 to 20.9 scfm). The gas chromatographic system used for measuring SO₂ concentration levels was found unsatisfactory due to its irregular and irratic response, and as a result of functional problems involving the SO₂ injection technique and the required analysis time.
An equilibrium combustion analysis for a high sulfur-content coal was accomplished using a computer program developed by NASA at the Lewis Research Center. Unlike procedures commonly used for coal combustion analyses, which assume complete combustion, this program uses the minimization of Gibbs' free energy to predict the extent of reaction (combustion). Combustion products calculated by this program for Christian County, Illinois coal are presented. / M.S.
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Effects of calcium, sulphur and potassium concentration in overburden on quality of strip mine drainageNewell, Virginia Elisabeth 12 June 2010 (has links)
Planned strip-mined land reclamation that minimizes damage of the environment is vital for preservation of water quality, especially with present increased emphasis on coal production. Analysis of overburden is becoming mandatory in order to plan effective placement of material in spoil piles. One rapid technique with little sample preparation for determination of elements in overburden is scanning electron microscopy. This method was quantified in this study for determination of sulphur, potassium and calcium concentrations in cores from two watersheds in Raleigh County, West Virginia. These values were added to a water quality model to more accurately predict concentrations of elements in strip-mine drainage. Development of a method to predict elemental concentrations is helpful in determining potential environmental damage to a watershed. A correlation analysis was conducted using water quality data before and during mining to substantiate data received in the core analysis.
Information as is determined in this study’ can aid mine operators in selecting potentially deleterious strata for subsurface placement and in retaining more environmentally beneficial strata for use on spoil surfaces. Knowledge of potentially hazardous substances in overburden should lead to more efficient revegetation procedures by surface mine operators. / Master of Science
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