Dry etching processes for patterning of ferroelectric thin films using environmental benign etching gases was developed. The PbZr_xTi_1-xO3 (PZT) and RuO₂ films were patterned using CHCIFCF₃ and O₂. Selective etching between PZT and RuO₂ was achieved by changing the gas composition. The etched profile and surface were anisotropic and smooth. Surface residues were found after etching and were removed by a post-etch heat treatment. In addition, the reactive ion etching damage to PZT ferroelectric capacitors was first defined and studied using Ar and CHCIFCF₃ etch gases. It was found that the internal field developed in the capacitors during etching was responsible for causing the shift in hysteresis loop and the reduction of switchable remnant polarization. The increase in leakage current after etching can be attributed to the electrical properties change at the interface of Pt/PZT and the roughness along the side wall of a PZT capacitor after RIE. Furthermore, the etching damage effect to PZT capacitors was substantially recovered by post-etching annealing at 400 °C for 30min. The dry etching processes for new layered structure SrBi₂(Ta_xNb_1-x)₂O₉ ferroelectric films were developed in this research using CHCIFCF₃and SF₆ as etching gases. Physical sputter etching was the dominant etching mechanism in RIE of SBT and SBN films. Sr-enrichment on the etched surfaces was observed for both SBT and SBN films and was removed by post etching cleaning solution developed in this research. From a technological point of view, a practical dry etch process for etching of RuO2 films was first developed using O₂/CF₃CFH<sub>2<sub> (R-134) etching gases. The maximum etch rate, 1625 Ȧ/min, of RuO₂ was obtained at pressure of 75 mTorr and rf power of 200W in Or₂-2.5% CF3CFH2 discharge. RuO₂ films were successfully patterned under these conditions using SiO₂ as the etch mask. The etching mechanism was investigated from a scientific aspect. Several impurity gases, such as N₂, SF₆, and H₂, were added into the oxygen discharge for this investigation. Atomic oxygen is the dominant active species reacting with RuO₂ films to form RuO₄ volatile products. The addition of impurity gases in oxygen discharge increased the generation rate and/or the life-time of atomic oxygen in the reactor thereby enhancing the etch rate. CF₃CFH₂ gas had the strongest effect in increasing the generation rate (G), and accordingly, addition of a small amount of CF₃CFH₂ in oxygen discharge yielded the highest etch rate. The decrease in the etch rate with increasing mole fraction of R-134 in the feed (>5%) was mainly due to the F atoms reacting with RuO₂ to form a surface residue layer that occupied surface reaction sites impeding the reaction between O and RuO₂. / Ph.D.

Recently, studies have suggested that the incidence of sexual violence within the college community is extremely pervasive {Finley & Corty, 1993; Koss & Oros, 1982; Muehlenhard & Linton, 1987). Popular media has targeted alcohol and Greek organizations as primary causes of sexual aggression on campus. However, few empirical studies have investigated this notion. This study broadened the empirical base to this line of research and may assist in developing preventative strategies by identifying student groups with high levels of sexual aggressiveness on college campuses. A quantitative approach was used to examine if significant differences existed for undergraduate students based on gender and Greek affiliation in their self-reported incidence of sexual victimization experiences, sexual victimization experiences with alcohol involved, and sexual aggressiveness. An attitude measure was also examined. The survey was administered to students in a variety of classes during the 1991-92 academic year. The respondent group for this study consisted of 1276 subjects, of which 308 were Greek affiliated. Frequency data, means, and standard deviations for all relevant variables are reported. The data were analyzed using four separate general linear model procedures, one for each dependent variable. Results found significant differences for both gender and Greek affiliation for sexual victimization, sexual victimization with alcohol involved, and sexual aggressiveness. Gender was also found to play a significant role in the attitude measure. / M.A.

This thesis analyzes the simulation of a Single Channel Ground and Airborne Radio System (SINCGARS), currently in use by the United States Army. Although this radio was mainly designed as a voice radio, it also has the capability to transmit data messages. The amount of voice traffic which is capable of flowing through the channel, without causing detrimental effects to users, is studied. The struggle to transmit data versus voice is considered. Various other factors capable of influencing performance are explored. These consist of net access delay, net size, frequency of information transmission, and most importantly, data message transmission delays. The radio net is modeled in EXTEND, a commercial software package. The program simulates preselected and quantified data as well as coded voice data. The data is then processed through the single radio channel. Message transmission delays are calculated by EXTEND and examined for individual users. The primary contribution of this thesis is the development of an analytical approximation to estimate message transmission delays. The analysis is based on simulated data from EXTEND. A general expression is derived for each member, or user, on the SINCGARS net. This is an effort not only to simplify and generalize the method of estimating delay, but it also serves to shorten the amount of time spent on analysis, by reducing the dependence upon simulation. Applications of this research include the analysis of SINCGARS, under the Inter-Vehicular Information System (IVIS) protocol, using simulation and statistical approximations. If the performance of a new system can be accurately evaluated using a general expression, thus eliminating the need for repeated simulations, performance and system analysis time can be significantly reduced. / M.S.

Past psychophysiological research has led many investigators to believe that perceived effort during exercise is lower with greater active muscle mass (Hagan, et al., 1983; Sargeant & Davies, 1973; Shephard, et al., 1992; Stenberg, et al., 1967), presumably because the effort is distributed to more muscle tissue. The purpose of this investigation was to compare the Ratings of Perceived Exertion (RPE) of college-age females during steady-state leg-only (LE) and combined arm-and-leg exercise (ALE) using the 15-point Borg RPE scale. Volunteer subjects were 16 healthy, physically active female students, mean age 21.0 years (SE 0.33) and a percent body fat of 22.1 (SE 1.1). Each subject completed a graded maximal exercise test on a Monark 880 LE cycle ergometer. Exercise intensity during two subsequent 30-minute exercise treatments was then maintained at the HR corresponding to 70% of the subject's tested functional capacity (VO2max). The exercise treatments were two randomized bouts separated by at least 48 hours but not more than one week, one each using a Monark 880 cycle ergometer (LE) and a Schwinn AirDyne (ALE). Mean RPEs were 13.7 (SE 0.2) for the LE session, and 13.0 (SE 0.3) for the ALE session. Mean heart rates were 172.8 bpm (SE 1.18) for the LE session, and 170.6 bpm (SE 1.26) for the ALE session. Mean VO₂s were 30.7 ml/kg/min (SE 0.76) for LE and 30.1 ml/kg/min (SE 0.68) for ALE. Workload means were 120.0 Watts (SE 3.83) for LE and 127.7 Watts (SE 4.11) for ALE. Repeated measures ANOVA revealed no significant differences between the two modalities for RPE (p < 0.07) or VO₂ (p < 0.12), but significant differences for HR (p < 0.006) and workload (p < 0.0003). Tukey's post-hoc test for simple effects determined that time effects were significant (p < 0.0001) regardless of modality, with RPE and HR measurements at minutes five and ten differing from those at minutes 15, 20, 25, and 30 (p < 0.05) during both LE and ALE bouts. The results of this investigation indicate that no significant perceived effort difference exists between these LE and ALE modalities over a 30-minute exercise bout at the same HR-regulated intensity. / M.S.

The purpose of this study was to document pictorially the exterior architectural style and the interior configurations of Virginia high schools, and to relate these designs to major curricular trends. This study, using historical research methods, will preserve Virginia's secondary educational institutions for future resource. A history of the high school in Virginia was developed as a background for the study of school architecture. The methodology used in this study produced a selection of high school buildings which best represented an architectural period, beginning with the oldest high school building still in use to the most recently constructed schools. All 284 public high schools were surveyed to obtain data on the date of construction, condition of the structure, presence or absence of additions, and other pertinent data concerning the building. From this population, seventeen schools were chosen to represent school buildings in each of the decades covered. Selection of the schools was based on the following criteria: 1) Date of original construction; 2) Completeness of original structure (The pristine element of an existing building is dependent upon the absence of major renovations, changes, or additions to the structure which would drastically alter the architectural style.); 3) Overall rating by the building principal (condition, design, and functional ability to serve students, staff, and community); 4) Noteworthy architectural or unique educational features; and 5) Subjective comparison, (examining floor plans and photographs). Each of the buildings in the sample was visited to obtain data relating to curricular emphasis in the design. Each architectural period was researched for significant educational and curricular trends that may have influenced high school design. The outcome of this study was a document containing a written and pictorial history of the architectural and curricular features of Virginia high schools. / Doctor of Philosophy

Urbanism and its associated architecture not only takes place in designated city areas but also in the Realm of the Middle Landscape. Although it is hardly possible to invent a new architecture, the necessity remains to think about questions of urbanism and its built structures in the context of history, technology and sociology. One interpretation which challenges the current urban development, such as the issue of the sprawl of mid size towns, has the potential to direct planning tools and clarify intentions towards a more differentiated strategy of orientation. This approach to design opens the possibility to develop a higher level of sophistication by articulating building elements within classical parameters such as proportion, geometry and composition. The filtering into a modern context which includes the knowledge of attributes of contemporary materials and technology will facilitate the process of transfer. / M. Arch.

Master of Architecture

This investigation examined the ability of the Veterans Specific Activity Questionnaire (VSAQ) to predict the functional capacities (expressed in metabolic equivalents or METs) of twenty male participants previously diagnosed with CAD who were referred for exercise testing as part of their participation in a community based exercise program. On the morning of their normally scheduled GXT, each individual completed the VSAQ and was administered a maximal exercise test on a treadmill utilizing a ramp style protocol based on their self estimation of functional capacity. Respiratory gas exchange values were recorded throughout and analyzed via stepwise linear regression with respect to several experimental and demographic variables such as age, BMI, percent body fat and time since entering a cardiac maintenance exercise program. The only variable to contribute significantly to the prediction of FC with regard to exercise capacity as measured by respiratory gas analysis was the VSAQ. The VSAQ explained 22.% of the variance in actual performance and this variable only showed a modest association with the criterion measure (r = 0.47 SEE 2.25, p <0.05). A similar finding was noted when this criterion of exercise performance was estimated from treadmill speed and grade equations. In this case, the VSAQ accounted for 34% of the variance in exercise performance, i.e., r=0.58 (SEE 2.16, p <0.05). The final regression equation by which the VSAQ might be used to predict exercise capacity by the gas exchange criterion was: METs = 4.21 + 0.50(VSAQ). The final regression equation for prediction of MET exercise capacity by speed/grade at peak exercise was: METs = 4.60 + 0.65(VSAQ). / Master of Science

The purpose of radar signal processing is to extract desired data from radar signals. Testing of the radar signal processor requires that one produce a test consisting of a sequence of digitized radar sensor data. If the signal processor is modeled in VHDL then the sequence of sensor data will be applied to the model in a VHDL test bench. Generation of the sensor data and sensor models for VHDL testbenches is a labor intensive task which cannot be performed manually. This thesis concentrates on the transformation of the mathematical representations of Synthetic Aperture Radar signals and sensors into VHDL models, and provides the mathematical underpinning for the other testbench work. Cadence/Comdisco SPW is used to describe the behavioral model of the test bench, which is hierarchically constructed using the primitives in the SPW library. A parameterized VHDL model is constructed from the block diagrams in SPW to generate the test for the VHDL signal processing model under test. / Master of Science

Single story, rigid gable frames are commonly used by the metal building industry for light, industrial buildings. These rigid gable frames are usually constructed of built-up, web tapered, columns and rafters for reasons of economy. The tapering of the webs optimizes the members to develop a fully-stressed design. The purpose of this study was to investigate the AISC LRFD strength of the rigid knee portion of gable frames. The experimental portion of this study was sponsored by Kawada Industries, Inc., Costa Mesa, California. Eight specimens consisting of a tapered column and a portion of the tapered rafter were tested to failure under three types of loading that approximated the gravity, lateral, and cyclic load cases. The analytical portion of this study investigated the LRFD strength of the eight tapered knee specimens. The calculated LRFD strengths were compared to the experimentally obtained capacities. It was concluded that the LRFD shear strength provisions were overly conservative. The LRFD shear strength for tapered members was limited to the elastic or inelastic buckling strength of the web plate. Procedures for the application of the LRFD tension field action model to account for the post-buckling strength of tapered webs were presented. The application of tension field action to end panels, panels with large aspect ratios, and hybrid girders was also addressed. It was shown that the application of the LRFD tension field model to tapered members produced less conservative results. / Master of Science