The current study examines the effects of social comparison information and purpose of appraisal on the leniency and accuracy of self-appraisals of performance. Previous research has shown that providing comparison information decreases the leniency and increases the accuracy of self-appraisals. While these effects of comparison information quantity are documented, no research to date has examined the effects of comparison information quality on self-appraisal. It was hypothesized that self-ratings would be less lenient and more accurate when comparison information was presented via a written medium as opposed to an observational medium. While the results clearly support the role of comparison information quantity, the role of quality was generally not supported. Moreover, there was a discrepancy between the free recall measure and self-ratings with regard to the role of quality of comparison information. Past research indicates that self-appraisals conducted for reward purposes are more lenient and less accurate than those conducted for feedback purposes. The current results provide further support for this trend. Possible explanations for the current results, implications for past research, and suggestions for future research are discussed. / Master of Science

The thesis participates in the critical evaluation of the modernist concept of 'homogenizing of cultural differences', and in the narrower architectural context against the idea of the type, module, and system. Although the thesis is as such a part of the post modernist demand for an emphasis of cultural heterogeneity which is characterized by a newly understood responsibility of creative acting and 'otherness', the inquiry suggests an opposed approach to the handling of such creative tension and propounds that the pantheistic and deterministic culture can be interrupted actively by an concept of order according to competitive individual expression. Pertaining to architecture, the deep suspicion towards systematization and rationalization is expressed in the rejection of the 'type in architecture' which leads to a critique of an architecture which has its essence in structure. The thesis recognizes the materialist tectonic principle as a manifestation which tries to find its justification in the oneness of man with nature; moreover, such an architectural understanding tends to make the various individual forces evolve to a norm. The thesis dismisses such a motivation and argues that man aims towards the expression of architectural symbols which spring immediately from the creator's character and manifest man's image of his values and his place in the universe. The thesis further argues that the a-tectonic 'will to form' acts through the contest of individuals and that the creation of architecture is supported by the 'Dionysian' cognitive qualities of the architectural material space. / Master of Architecture

Wildlife managers, through the use and management of their areas, influence water quality and quantity on and off site. Natural resource managers are coming under increasing pressure to preserve ecosystems and natural processes while producing a "optimum" balance of recreation, wildlife habitat, and natural resource products, and to justify their decisions. Water is a critical component to consider when managing recreation, wildlife, and wildlife habitats, and is itself a valuable resource to be managed. Unfortunately, the knowledge of hydrology is imperfect, effects of each management option are hard to predict, and field studies are time-consuming and expensive. The purpose of this study was to evaluate a simple hydrologic model as a tool for assisting wildlife managers in comparing potential hydrologic effects of different management options and of natural and anthropogenic site disturbances on eastern forested mountain watersheds. A number of existing hydrologic models were considered. AGNPS (Agricultural Non-Point Source pollution model) was chosen for its simplicity, applicable outputs, and successful use around the country. AGNPS was applied to a watershed at the Coweeta Hydrologic Laboratory in North Carolina. After adjustments, a baseline run was made, then the model was manipulated to simulate and compare several hypothetical management scenarios. This study demonstrated the potential utility of hydrologic models in wildlife management or other natural resource management decision-making processes. Model outputs may be useful in evaluating the relative impacts of alternative land-use decisions. Some problems remain in modeling the hydrology of eastern forested mountain watersheds. / Master of Science

The purpose of this research is to develop an understanding of Multichip Modules, (MCMs), more specific those fabricated with a Low Temperature Co-fireable Ceramic (L TCC) tape systems. The study will consist of designing, processing, and testing two generic MCM test patterns. The effects on signal propagation caused by vias and wire bonds, crosstalk for surface and embedded transmission lines, crosstalk between vias, effects of bends in transmission lines are studied and discussed in this work. Time Domain and Frequency Domain measurements are performed and presented in this thesis work for electrical characterization of MCM structures using L TCC systems / Master of Science

Young mine soils constructed following surface-mining for coal contain low levels of organic matter and nitrogen. It was hypothesized that nitrogen-fixing plants could be incorporated into a reforestation system in a manner that would meet the short term and long-term nitrogen needs of crop trees while rebuilding the soil and litter nitrogen pools and restoring a stable nitrogen cycle. The nitrogen status of two interplanting studies containing legume ground covers was examined. The first study site was mined prior to 1940 and subsequently abandoned. In 1988, the land was reclaimed, and an interplanting study was established in 1990. Pitch x loblolly pines (Pinus x rigitaeda) and eastern white pines (Pinus strobus L.) were interplanted with four nitrogen-fixing species: black alder (Alnus glutinosa L. IGaertn.l), black locust (Robinia pseudoacacia L.}, bicolor lespedeza (Lespedeza bicolor) and autumn olive (Elaeagnus umbel/ata Thwnb.). Pitch x loblolly pine survival was good; however, eastern white pine survival was only fair, averaging 54%. All of the nurse tree species with the exception of black alder had fair survival rates. Black alder survival was extremely low at 19%. After the third growing season, a ground cover dominated by legumes averaged 79% cover. The black mine spoil on the site was extremely rich in nitrogen, averaging 5,115 mg·kg-1. When the black mine spoil was mixed with the native topsoil, a mine soil that was created had an extremely variable total nitrogen content. However, low mineralizeable nitrogen levels suggested that the nitrogen in the mine spoil was not generally available. Pine responses to the four nitrogen-fixing species were compared. Nurse trees had no effect on pine growth after three years. Pine foliar nitrogen levels were adequate across the study site even in the control treatments and in the microsites where few legumes were present. Microsites surrounding 50 pines of each species were studied. The pitch x loblolly pines grew larger at lower pH levels and higher coarse fragment content reflecting the pines' preference for moderately acid soils, coarse-textured soils. Some competition was present between the crop trees and herbaceous cover, but it was not a controlling factor in pine tree growth. / Master of Science

Research shows residential students have varying perceptions of satisfaction with their residential environments. It has also been shown that levels of satisfaction may differ between students based on variables such as hall size, organization, gender, or class standing. This study examined residence hall satisfaction levels for students living in the halls at Virginia Tech. The research question was: what are the differences in levels of satisfaction as measured by the Student Residence Environment Scales among residential students based upon hall size, hall type, and gender. The SRES was administered to approximately 1050 students, divided equally between six halls chosen to represent the variables of size, gender, and type. There was a 53% return rate with 55% female responses and 45% male responses. The data were analyzed using the SAS system and three-way ANOVAs were run on all 17 subscales. The results supported the research question in that there were significant differences between scores on the 17 subscales based upon hall size, hall type, and gender. Main effects and significant interactions between independent variables were found for all 17 subscales, indicating that hall size, hall type, and gender affect student satisfaction levels in the residence halls. The number of subscales and interactions do not allow for an abbreviated summary to be made; however, in general students were satisfied with the residence halls at Virginia Tech. The results of the study indicate that there are areas in which residence life personnel could make changes in policies and procedures which would increase levels of satisfaction in the residence halls. / Master of Arts

The effects of particle shape on bedload transport and a wide range of bedload transport rates using both bed subsurface and surface layer based approaches are investigated using fractional transport analysis with a similarity approach. Bedload transport data from a stream containing flat, low density shale particles indicates that the reference transport critical shear stress for the median surface grain size is approximately 2 to 3 times higher than those for more spherical particles. This conclusion indicates a lower susceptibility of disc-like particles to initial entrainment and lower transport rates for given flow conditions than more rounded particles. Analysis of a wide range of transport rates verifies that the slope of the log-log bedload transport rate - bed shear stress relation decreases with increasing transport rate and becomes constant at very high transport rates. This result implies that the dependence of the transport rate on grain size decreases with increasing transport rate. Comparison of bed subsurface and surface layer based bedload transport approaches indicates that the two approaches produce similar transport - shear relations and reference shear stress values. / Master of Science / incomplete_metadata

In this thesis, a method of predicting the steady state, dynamic, electromechanical behavior of stack actuators (both electrostrictive and piezoelectric) integrated within complex structures is developed and experimentally verified. This research was motivated by a need to accurately predict transmission force, velocity output, and power consumption for a wide range of applications both terrestrial and space based. The relevant transduction equation / parameters are derived from basic principles. These results are experimentally verified with a PZT stack active member. The derivations are then extended to incorporate the effects of integrating the actuator within a host structure. Specifically, the equations needed to predict actuator output force, resulting velocity and drawn current are derived. To implement and test these results in a structure, the equivalent host structure impedance must be determined. This is done experimentally for a complex truss structure representative of a small satellite. These results are then used to prepare theoretical predictions which compare well with experimentally measured output force. Finally, the derivations are extended to the electrical behavior of active members integrated within truss structures. It is now possible to predict the electrical load imposed by the active member on the power supply system including the effects of coupling with the host structure dynamic boundary conditions. Two implications of this are considered. First, the required power demands directly influence the design and sizing of amplifiers, applied voltage levels and power systems. Second, the dissipative power from actuation losses contributes directly towards raising the internal temperature of an operating stack actuator. / Master of Science

Recent satellite measurements have found the range of solar radiation flux at the mean Earth-Sun distance to be from 1365 to 1372 W/m², or 1368 W/m² to within ±0.5 percent. This regularity is considered sufficient to permit the use of solar radiation as a source of energy for inflight calibration of radiometers designed to detect electromagnetic radiation in the solar spectrum. But direct viewing of the Sun would provide a flux considerably greater than the operating range of radiometers designed to observe typical Earth scenes. Therefore an attenuator is required. The Earth Radiation Budget Experiment (ERBE) radiometers, operational since 1984, relied on a mirror attenuator mosaic (MAM) to attenuate the solar energy. The ERBE MAM is an array of 105 tightly packed concave spherical mirrors with a black mask covering the surface between the hemispherical cavities and partially covering the cavities themselves. In principle, the reflection of solar energy by the MAM was anticipated to be independent of the solar incidence direction. Unfortunately, flight data revealed a variation with a solar incidence angle of as much as 20 percent for flux arriving at the detector during solar calibration. An improvement of the ERBE MAM design, suppression of the black mask, and reduction of the surface area of the spherical mirrors, has been achieved for the Clouds and the Earth's Radiant Energy System (CERES) radiometers, which will be operational sometime in the late-1990's. The topic of this thesis is the creation of a thermal-radiative model, based on the Monte-Carlo ray-trace method, to characterize the performance of the CERES MAM. The radiative analysis suggests that the current CERES MAM design is still somewhat less than optimal. The desired specifications are that the fraction of solar energy reflected by the MAM to the radiometer aperture be independent of the solar vector, and that the distribution of this reflected energy be uniform across the entire surface area of the radiometer aperture. The work reported here establishes that these specifications can be met by a simple reorientation of the MAM diffuser plate. / Master of Science

A method for determining the maximum control moments required for an aircraft to perform a velocity vector roll is investigated. The velocity vector roll is assumed to occur at constant angle of attack, constant velocity, and zero sideslip. A simplified set of equations is developed for the non dimensional control moments about the three principal body axes. These equations take on a form well suited for numerical optimization methods. The Schittkowski sap optimization code is used to provide fast, accurate solutions. The numerical method also shows the advantage of being adaptable to changing the airframe and flight performance parameters. An exercise to find the global control moment maxima was performed for a an F-18 with constant aerodynamic derivatives and a load factor of one. The optimization was run for a range of discrete steady state roll rates, roll mode time constants and velocities. The results showed trends for the maxima to occur at the highest steady state roll rate parameter, smallest roll mode time constant and lowest velocity. Each control axis maximum is specific to a particular orientation and angle of attack. For the roll axis, the maximum occurs at nearly zero angle of attack and 270 of wind axis bank angle. The yaw axis maximum occurs at the largest angle of attack (70) and 90 of wind axis bank angle. The pitch maximum occurs near 270 of wind axis bank and 55 angle of attack, but is highly sensitive to the selection of Cma . All control moment maxima occur at a flight path angle of O. The roll and yaw control moment maxima occur upon a maximum roll input starting from rest at the specified orientation and angle of attack. The pitch control maximum occurs at the steady state roll rate when the proper orientation and angle of attack is encountered. / Master of Science