Communication is one of the most important aspects in any project. This is especially true in the case of projects in the Architecture-Engineering-Construction industry. The traditional forms of communication such as drawings and specifications are not adequate in achieving the required levels of understanding among project personnel. The concept underlying the project, i.e. the collection of arguments and decisions and the thought underlying them are not communicated. This may lead to various project personnel having differing views about the requirements of the project. This research focuses on an attempt to communicate the thought process underlying the project to the various project personnel so that they have an unambiguous and clear understanding of the essentials of the project and to test the success of this attempt using a field example. The thought process or concept underlying a project is defined as the design rationale for the project. There have been many approaches to the communication of the concept that is the basis of a project. After a literature survey of the various approaches, the design rationale approach, which attempt to explicitly communicate the rationale was chosen. Considering the various definitions and models of design rationale, a model based on the Lee and Lai representation was chosen as the basis for this work. Making certain adaptations to the Lee and Lai representation based on the requirements of the industry, a representation structure consisting of rationale networks was developed. Based on the rationale representation, DRARS, an object oriented rationale representation tool was developed. The rationale was represented in DRARS using object networks. DRARS was then tested on an actual project involving the renovation of a school building. Based on the collection and representation of the rationale, DRARS was evaluated for its abilities to easily author and represent design rationale. DRARS performed well in achieving both the objectives of ease of authoring and the richness of representation. DRARS, however stores rationale that is not computer processable and presents the rationale for human interpretation. DRARS also uses multimedia to support the richness of the representation. / Master of Science

A computational study of the flow in a tandem inducer/impeller rocket pump has been performed using a 3D elliptic flow program including viscous effects. The axial inducer has four blades and the centrifugal impeller has eight main blades and sixteen splitter blades. The purpose of this thesis is to investigate the flow in the turbopump, and check its proper design. A literature review discusses both elements of the pump, and then analyzes the possible matching configurations. More details are given for the geometry of interest. The generation of a single zone 3D grid for the tandem combination is then presented in detail, after which simpler grids are derived for the inducer alone. The results of the 3D tandem inducer/impeller calculation are presented extensively to provide good knowledge of the flow inside this little investigated configuration. Velocity vectors, static pressure and rotary stagnation pressure are shown in meridional and blade-to-blade views. A balanced flow split is achieved in the impeller main-blade passages. Cavitation inception is also discussed. Additional 3D calculations are performed for the inducer alone, with varying exit geometry (axial or radial). Comparisons of geometry influence on the inducer flow are carefully investigated, as well as the influence of the impeller. The impeller slightly modifies the inducer exit flow but not its overall performance. As a consequence, it is found that separate design calculations could be performed for the inducer and the impeller. The latter would use the inducer circumferentially averaged exit flow as its inlet conditions. It is suggested that impeller suction performance be optimized using tandem inducer/impeller calculations. / Master of Science

Previous studies demonstrate that members of the strictly aerobic genus Gluconobacter produce detectable quantities of hydrogen sulfide (H₂S) when incubated in SYP medium (5% sorbitol, 1% yeast extract, and 1% peptone) containing thiosulfate. This finding is puzzling, since the microbial evolution of H₂S is characteristic of anaerobic or facultative bacteria. The goal of this research was to determine the physiological role of H₂S evolution for the gluconobacters. A methylene blue method was used to quantify the amount of H₂S evolved from cultures grown aerobically for 3 days at 28°C. Five of the six tested strains of gluconobacter evolved from 6 to 68 μg of H₂S. Strains which grew to a higher density (> 300 μg cell protein/ml ) evolved between 10 and 68 μg of H₂S. Strains which grew to a lesser extent (< 140 μg cell protein/ml ) evolved no more than 6 μg of H₂S. Uninoculated SYP medium containing 1% thiosulfate showed no evidence of H₂S evolution; however, sterile SYP medium with decreasing concentrations of yeast extract and peptone showed increasing amounts of H₂S evolved. When SYP medium was exhausted by gluconobacter growth for 72 hours, then supplemented with thiosulfate, filter sterilized, and incubated for 3 days at 28°C, these sterile solutions evolved over 400 μg of H₂S. A drop in pH. similar to that which occurs during gluconobacter growth, is not sufficient to evolve H₂S. My results to date suggest that H₂S evolution results not from gluconobacter metabolism, but rather from spontaneous decomposition of thiosulfate and the depletion of media components during growth. / Master of Science

Master of Science

Ph. D.

Both the Advanced Mobile Phone System (AMPS) and the narrowband version (NAMPS) use frequency modulation (FM) in a frequency division duplex mode. Because such systems typically use the same frequency bands in nearby cells, co-channel interference can be a significant problem. A typical digital implementation uses a quadrature demodulation algorithm to estimate the instantaneous frequencies of FM signals and recover the original modulating signal. The use of parametric spectral estimation techniques can often provide higher resolution frequency estimates for closely spaced signals, such as co-channel FM signals. A parametric method based on forward-backward linear prediction is implemented to create a model-based demodulator for AMPS and NAMPS cellular signals. This algorithm demodulates the signal by estimating the instantaneous frequency of the principle component present. In addition, improved resistance to noise and co-channel interference is gained by performing a singular value decomposition on the signal data and then estimating the parameters of the model using only the desired components of the decomposition. Examples are provided showing the performance of the demodulator in various signal environments. Experimental results show 5 to 22 dB improvement in demodulator output mean-square-error relative to a quadrature demodulator for various channel conditions including Rayleigh fading. The ability of a demodulator to reject severe co-channel interference and channel noise could allow significant increases in cellular system capacity and performance. / Master of Science

Throughout aviation history, man has had a particular fascination with the quest for speed. Initial studies show that hypersonic atmospheric travel could greatly change the world of aviation as we know it today by making access to space much more routine and making all regions of the world accessible with non-stop, minimal flight time service. Supersonic combustion ramjet (scramjet) propulsion will play a key role in the development of these vehicles. Many more steps need to be taken, particularly in propulsion, before a world of hypersonic travel can be fully realized. This thesis presents the research results of the conceptual design and preliminary analyses of a scramjet test vehicle concept called the Air Launched Scramjet Test Vehicle, or ALSTV. The ALSTV proposes to use the Orbital Science Corporation's (OSC) Pegasus® vehicle to boost a subscale scramjet module to 100,000 feet and cruise/scramjet testing for one minute at speeds between Mach 8.0 and 8.2. It is estimated that the vehicle will cost between $35-40 million to develop and fly. / M.S.

Three greenhouse and two field plot experiments were conducted to determine the influence of seaweed extract and other plant growth regulators on forage quality and persistence of endophyte-infected (Acremonium coenophialum Morgan-Jones and Garns) and endophyte-free tall fescue (Festuca arundinacea Schreb.). The influence of plant growth regulators on forage quality of endophyte-infected tall fescue and performance of wether lambs was evaluated in two grazing trials. Greenhouse and field experiments were randomized block designs. Results from greenhouse studies varied but indicated increased (P ≤ .05) root strength and decreased (P ≤ .01) pressure required to extract moisture from leaves due to treatment. Analysis from greenhouse and field studies indicated little effect on fiber components, nonstructural carbohydrates, and crude protein. In tall fescue grazed by lambs, pyrrolizidine alkaloid concentration was decreased (P ≤ .05) between seaweed extract treatments. Ergovaline tended (P ≤ .08) to decrease in all treated forage and was 4.26, 3.78, 3.59, and 3.48 µg g⁻¹ (S.E. = .28) for control, 1703, and 3406 g seaweed extract ha⁻¹, and 19.1 L VTMix ha⁻¹, respectively. Lambs grazing treated forage in July had increased (P ≤ .05) ADG (.03 vs a mean of .11 kg gain per d for control vs treatments, respectively). Linear trends (P .13) of increased serum vitamin A and increased (P ≤ .10) whole blood Se due to seaweed extract treatment were observed. Serum Se values were 241, 264, and 274 ng/ml (S.E. = 13) for control, 1703, and 3406 g seaweed extract ha⁻¹, respectively. Results indicated that plant growth regulators may have potential to increase plant persistence and decrease toxicity of tall fescue. / M.S.

Traditional com fertilization methods of broadcasting N fertilizer, and applying P fertilizer to soils testing high to very high in plant-available P, can be inefficent. Experiments were conducted at several locations in Virginia to evaluate if band applications of N fertilizer are more efficient than surface broadcast applications, to determine optimum starter-band and sidedress N rates for com grown in Virginia, to evaluate possible indicators of optimum starter-band and sidedress N rates, and to determine if there is any response to P fertilizer application to com grown on soils testing high to very high in plant-available P. Starter-band N rates of 11, 34, 56, and 78 kg ha⁻¹, and a treatment of 67 kg ha⁻¹ broadcast plus 11 kg ha⁻¹ in a starter-band, were applied in combination with sidedress-N rates of 0, 67, 134, and 202 kg ha⁻¹. In the phosphorus experiment, starter-band rates of 0, 22, 45, and 67 kg P₂O₅ ha⁻¹ were applied. Band application of N increased com plant tissue N content at most locations compared to broadcast application. Fifty-six kg ha⁻¹ was determined to be an economically viable starter-band N rate for com grown in Virginia. Optimum sidedress N rates were determined to be site- and season-dependent and no indicators of optimum starter-band N rates or sidedress N rates were observed. On soils testing high to very high in plant-available P, grain yield did not respond to additions of P fertilizer. / M.S.

"Architecture may be many things: ie. there is no one thing that is Architecture." As tired as this phrase may be, it is extremely valid nonetheless. From Frampton's <i>Critical Regionalism</i> to Derrida's <i>Deconstruction</i>, this declaration is rendered indisputable. Whatever the architecture does become, however, it can do so only from a boundary [as in both Heiddeger's suggestion of a <i>beginning</i> and in the Greek belief that that is where a thing "begins its presencing"].₁ It is the boundary--the WARP [from Hertzberger]--that permits the opportunities for making to come into being. "Making" can thereby be considered to be the other critical component--the WEFT--in this process of becoming. This thesis is the beginning of a search for such a method of thinking in architecture. 1. Heidegger, Martin. <i>Poetry, Language, Thought</i> (Harper & Rowe, Publishers, Inc., 1971), p. 154. / Master of Architecture