Masters Theses

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Browsing Masters Theses by Content Type "Dissertation"

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    Effect of operating variables on composition of overhead vapors and residue from a continuous flash distillation for the system methanol-water at atmospheric and sub-atmospheric pressures
    Littlejohn, Charles Edward (Virginia Polytechnic Institute, 1953)
    Although distillation studies have been made for many types of rectifying columns under various conditions of operation, no systematic study has ever been made of the process that is the basis of rectification, e.g., flash distillation. It was the purpose of this investigation to study the action of the system methanol-water under-going flash distillation under various conditions of temperature, agitation, and rate of feed at a total pressure of 500 millimeters of mercury, absolute. The distillation took place in a nine inch diameter, electrically-heated, controlled temperature and pressure, cylindrical still 14 inches high. The liquid phase was agitated by the rotation of an externally driven 1-1/2-inch square paddle. An aqueous 25 weight per cent methanol solution was fed to the still in which the solution was subjected to flash distillation under conditions of a liquid hold-up of 445 cubic inches; vaporizing temperatures of 172 °F, 166 °F, and 162 °F; stirrer speeds of zero, 500, 1000, 1500, and 2000 revolutions per minute; and feed rates varying from 0.01 to 0.50 pounds per minute. From the results obtained it was concluded that the fraction vaporized was a function of the feed rate as follows: Z K1(R1 - R2)-b) Where: Z fraction vaporized K1 fraction vaporized when the term (R1 - R2) was equal to one R1 feed rate, pounds per minute R2 feed rate when residue rate was equal to zero, pounds per minute B a constant for a given temperature and stirrer speed. The fraction vaporized was directly proportional to the stirrer speed and the vaporizing temperature. The vale of the fraction vaporized varied from 1.0 to 0.04. The composition of the distillate was an exponential function of the feed rate as follows: xd K2(R1 - R2)a where: xd distillate composition, weight per cent methanol K2 distillate composition when the term (R1 - R2) was equal to one, weight per cent methanol. R1 feed rate, pounds per minute R2 feed rate when the residue rate was equal to one, pounds per minute a a constant for a given temperature and stirrer speed. The greatest degree of separation, as measured by the difference in distillate and residue compositions, occurred at stirrer speeds of zero, 1000, and 500 revolutions per minute at vaporizing temperatures of 162 °F, 166 °F, and 172 °F respectively. Some dynamic values of the distillate composition exceeded the static or thermodynamic values, for example, the theoretical value of the distillate composition of 68.5 weight per cent methanol at 162 °F was exceeded at zero and 500 revolutions per minute for feed rates in excess of 0.12 and 0.16 pounds per minute respectively. At 172 °F and 166 °F, the heat input as Btu per pound of distillate increased with increasing feed rates for feed rates from 0.022 to 0.122 pounds per minute and decreased with increasing feed rate for feed rates from 0.122 to 0.450 pounds per minute all at constant stirrer speed. An average value of the heat input of 1500 Btu per pound of distillate was obtained at 172 °F for stirrer speeds from zero to 1000 revolutions per minute and at 166 °F for stirrer speeds from zero to 2000 revolutions per minute. At 162 °F the heat input as Btu per pound of distillate increased with feed rate at all feed rates from 0.01 to 0.50 pounds per minute with an average value of 2000 Btu per pound of distillate being obtained. The dynamic equilibrium ratio was related to the product of the stirrer speed and the hold-up time as follows: N xD/xs K3(n th)d where: N dynamic equilibrium ratio xD distillate composition, weight per cent methanol xs composition of the liquid in the still at equilibrium, weight per cent methanol n stirrer speed, revolutions per minute th hold-up time, minutes K3 a constant for a given temperature d a constant for a given temperature
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    An ethnographic study of the well-being of elderly people in a matrilineal society in Malawi, Africa
    NyaManda, Mala Mwanjiwa (Virginia Polytechnic Institute and State University, 1995)
    An ethnographic study of 30 elderly men and women was done in a matrilineal group in Malawi, a small landlocked country in southeastern Africa, with the purpose of determining how societal change influences the well-being of the elderly. The study was carried out on the outskirts of the capital city and in a rural area so as to draw a comparison on societal change. Well-being was defined as the subjective evaluations of personal life experiences in terms of health and functional status and access to resources (George & Bearon, 1980). A theoretical framework that combined symbolic interaction, social exchange and modernization theories was used in order to get a larger understanding of human relationships at both the micro and macro levels. The combination of exchange theory and symbolic theory has been suggested by other researchers (Mancini & Blieszner, 1989 & Mutran & Reitzes, 1984). Qualitative data analysis method was adapted from McCracken (1988). The purpose of the analysis was to develop themes of logical interpretation of the respondents view of well-being. Four interrelated themes emerged in the study as affecting the well-being of the elderly. Societal change had the most influence with presence of biological children, socio-economic status of adult children and gender of adult children as the other themes. Societal change was occurring even in rural areas such that the extended family which traditionally provided care to elders, is seen to be shifting its responsibility to biological children. Results also showed that environmental factors such as drought and inflation also affect the well-being of the elderly. This study was the first documented gerontological study in Malawi. It is hoped that the results will generate interest at the action, policy and research levels. Therefore recommendations were made as to future research.
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    The professionalization of continuing education: an application of Larson's model
    Gravely, Archer R. (Virginia Polytechnic Institute and State University, 1983)
    As an alternative to the attribute approach to the study of professions, this research attempted to explain the level of professionalization in continuing education using Larson's model. From this perspective, the hallmark of professionalization is defined by the ability of an aspiring profession to create a labor market monopoly for certified practitioners. The methodology of the study provided a framework for conducting analyses of: 1) the organizational nature and development of continuing education; 2) practitioner attitudes and perceptions; 3) employer demand and production of adult/continuing education university graduates; 4) development of a unique knowledge base; and 5) consumer demand for continuing education programs. The findings of this research revealed that a high level of institutional fragmentation has inhibited the unified development and professionalization of the field. Practitioners do not show a propensity to undertake the difficult struggle required to transform continuing education into a true specialty. A weak, but a positive trend over time was found in the demand for university trained graduates. Similar trends were noted in the development of a unique knowledge base and production of university graduates. The consumer demand for continuing education programs has shown a pattern of tremendous growth over the last eleven years. In conclusion, the relatively low level of professionalization in continuing education can be explained by the application of Larson's model. Substantial linear relations were found between market control (dependent) and three independent variables. These findings provide a considerable body of evidence for supporting the validity of Larson's model of professionalization.
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    Structural evolution of the Roanoke area, Virginia
    Hazlett, William Henry (Virginia Polytechnic Institute, 1968)
    Approximately 70 square miles of Roanoke, Botetourt, and Bedford counties and northern Roanoke were mapped in detail in an attempt to reconstruct the structural evolution of this critical area situated at the arcuate junction of the Southern and Central Appalachians. The area includes approximately 15,000 feet of Paleozoic sedimentary rocks which range in age from Early Cambrian to Early Mississippian. Most strata are allochthonous and comprise four imbricated thrust blocks delimited from northwest to southeast by the Pulaski, Salem, Max Meadows, and Blue. Ridge faults. Indigenous rocks comprise the Read-Coyner Mountain and Bonsack anticlinal fensters and a probable fenster in Roanoke. The Read-Coyner Mountain fenster effectively separates the Catawba syncline and related Pulaski block structures to the northwest from the Salem block to the southeast, whereas the Bonsack fenster intervenes between the Salem and Max Meadows blocks. The eastern part of the area contains salients of the Blue Ridge, Max Meadows, and Salem blocks and a cross-structure delineated by northwesterly trending allochthonous and indigenous structural elements. Reconstruction of pre-thrusting basin geometry from structural and stratigraphic evidence reveals the following arrangement of structural elements from southeast to northwest: (1) Blue Ridge anticlinorium, (2) ancestral Catawba syncline and related portions of the Pulaski block, (3) Read Mountain anticlinorium, now partially exposed in fensters, and (4) Blacksburg synclinorium. Stratigraphic evidence indicates that each of these structures evolved, at least in part, contemporaneously with deposition. Thrusting was probably initiated in Mississippian time with inception of the proto-Pulaski fault in the basement beneath the Blue Ridge anticlinorium. Subsequent thrusting apparently originated from within the proto-Pulaski and Pulaski blocks in a progressive sequence from northwest to southeast. The proto-Pulaski fault propagated from the basement to near the base of the Rome beneath the rooted Catawba syncline and then was deflected surfaceward along the southeastern flank of the Read Mountain anticlinorium. After initial movement by plunger-like stresses, the incompetent, structurally low Rome became detached from the sole of this thrust block and was left behind, while overlying beds continued to advance along the newly defined Pulaski fault. The Pulaski block was then forcibly shoved over the Read Mountain anticlinorium and into the Blacksburg synclinorium until it encountered the structural front to the northwest. Continued application of tangential stress through the impounded Blue Ridge anticlinorium and yoked Catawba syncline induced Salem thrusting within the Pulaski block over the southeastern flank of the Read Mountain anticline. The Max Meadows fault probably originated by resurrection of the original Rome-soled proto-Pulaski block over the Bonsack anticline. The final stages of thrusting probably involved movement of both the Max Meadows block and the dismembered anticlinal Blue Ridge block. After thrusting, both allochthonous and indigenous blocks were folded and locally faulted, and nearly 10,000 feet of structural relief was imparted on the Pulaski thrust and overlying Catawba syncline. The Tinker Mountain-Coyner Mountain cross-structure probably originated contemporaneously with deposition but developed largely after thrusting by vice-like lateral compression and contemporaneous downwarp generated in the structural, possibly primary embayment of the Roanoke area.
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    The Virginia pattern of education for children under six in historical perspective
    Ashelman, Mary Miller (Virginia Polytechnic Institute and State University, 1984)
    This dissertation has a twofold purpose. The first is an exploration of the origins and development of education for children under six in Virginia, including the efforts made by both black and white educators working in this field. Data collected for this study indicate that black educators have shared many of the same goals as their white counterparts and have been leaders in their field. Several examples can be readily supplied to illustrate this point. The first laboratory nursery school at a black college was established at Hampton Institute in 1929. This laboratory school is recognized as the earliest in the United States for blacks and the first in Virginia for either race. Hampton Institute also provided undergraduate training for early childhood education leaders such as Dr. Evangeline Ward, the first black to become president of the National Association for the Education of Young Children (NAEYC). The second purpose of this study is to examine the formation of the Virginia Association for Early Childhood Education (VAECE) and its subsequent role. The VAECE is a state association that serves as a strong proponent for high quality educational programs for children under six in Virginia. It provides an avenue for interracial cooperation and facilitates child advocacy initiatives. As an affiliate of the Southern Association on Children Under Six and the National Association for the Education of Young Children, the VAECE is connected to a network of regional and national associations which share similar purposes. In the absence of comprehensive state and federal guidelines, the VAECE, which organized in 1957, will remain viable as a grassroots voice for young children and as a primary force in shaping the future pattern of education for children under six in Virginia.
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    Virginia school finance reform: a comparison of the Virginia public elementary and secondary school finance program from 1973-1981 in regard to fiscal equity
    Jones, Helene Boe (Virginia Polytechnic Institute and State University, 1983)
    The purpose of this study was to determine the extent to which fiscal equity has been advanced, if any, for the Commonwealth of Virginia since the current state aid funding system was implemented for the 1974-75 school year. This purpose was accomplished by examining three years of data to investigate whether any significant progress had been made toward a more equitable distribution of state and local revenues. Fiscal equity was defined in terms of two criteria: Per-Pupil Revenue Disparity and Fiscal Effort Neutrality. In addition, the standard of Fiscal Capacity Variance was used. Eight fiscal equity measures were applied to the data for the school years 1973-74, 1974-75 and 1980-81 to address the different discal equity criteria. The criterion of Per-Pupil revenue Disparity examined the variance in per-pupil revenue dispersion among the school divisions. The coefficient of variation, McLoone Index, Federal Range Ration and Gini Index were the fiscal equity measures used to address this criterion. Findings indicate that revenue disparities per pupil increased during the era of reform legislation in Virginia. The movement away from fiscal equity in terms of per-pupil revenue disparities, as shown by three of the four discal equity measures, other ancillary data, and comparison with similar state studies, demonstrates that if the intent of the Virginia school finance reform was to provide greater fiscal equity, it was not successful. The criterion of Fiscal Effort Neutrality was used to determine whether the pupils in the lowest discal capacity school division were given the same opportunity for identical per-pupil revenues for an equal amount of fiscal effort as the pupils in the highest fiscal capacity school division. The Federal Wealth Neutrality Standard was used to satisfy this criterion. Overall, the analysis indicates that fiscal equity as measured by the Federal Wealth Neutrality Test remained relatively constant over the three years. Virginia’s 68 percent of wealth neutral funds is considerably short of the required 85 percent to pass the test. The Fiscal Capacity Variance standard assessed whether a relationship existed between per-pupil revenues and school division fiscal capacity and wealth. Correlations, Elasticity coefficients, and a modified Gini Index were used to examine the relationship. Findings indicate that the link between per-pupil revenues and wealth has decreased marginally since enactment of the new funding formula. Yet the relationship between per-pupil revenues and fiscal capacity has increased, indicating movement away from the goal of fiscal equity.