Thesis (M.U.D.)--University of Hong Kong, 1997. / Includes bibliographical references (leaves 104-107) Also available in print.

M.Eng. (Engineering Management) / The residential and commercial urban sprawl towards green future is governed by the ability to overcome the challenges facing the high rise buildings sustainability. This research is dedicated to assess the high rise buildings’ energy towards near net-zero energy consumption from the point of view of production (the on-site energy generation via renewable technologies) and consumption (the usage of low consumption products). The features of the high rise buildings limit the on-site renewable energy production to solar energy, therefore the integration of solar application in the building’s facade plays a major role in the on-site energy production. Since, the relative roof area compared to the height of the high rise buildings is much less than the single family houses. Therefore, the use of the facade in high rise buildings for clean energy production becomes a major element towards its sustainability. There are several solar energy production techniques of which the most feasible and effective one is the combined electricity generation and heat collection via integrating PV and thermal collector system this system is denoted as solar Photovoltaic and Thermal (PVT) system. PVT system produces both electricity and heat at a higher efficiency from one integrated system on the same surface area exposed to the sun. For instance, PVT system produces approximately 43% more primary energy than a conventional solar thermal collector per unit surface area, and even around 96% more than a conventional Photovoltaic PV system (PVTwins, n.d). The concept of the PVT system was generated based on the fact that Photovoltaic (PV) system has typically 14-17% efficiency, so the rest of more than 80% is a lost energy; this lost energy goes in a form of heat. This heat could reach as high as 50oC above the ambient temperature resulting in structural damage as well as reducing the system efficiency by 25%. Recovering this harmful heat could reach up to five times thermal energy more than electricity from PV array (Hollick, 2011). From the energy consumption perspective, the air conditioning and ventilation system (HVAC) is considered as one of the highest energy consumer in the overall high rise buildings energy consumption (around 40%). This makes it an essential part of any high rise buildings energy solution therefore several low energy consumption HVAC systems has been developed recently. As such, absorption chiller presents one of the greenest HVAC system whereby it has no moving part, no electricity required, thermal driven system (use heat to produce cold) and could be operated by solar thermal energy. In this sense, the enterprise should respond to the increasing demand of the high efficiency buildings mainly by developing new solutions that enhance the latest green technologies and overcome the recent energy challenges.

Rhizoctonia zeae is a common pathogen of tall fescue and other turfgrasses in various regions of the United States. Disease caused by R. zeae typically occurs during hot, humid summer months when conditions are ideal for growth of the fungus but less than ideal for growth of tall fescue. While R. zeae has been reported on turfgrasses in several Mid-Atlantic states, there are no records of this pathogen being present in Virginia. Rhizoctonia isolates were obtained from samples of various turfgrasses exhibiting typical Rhizoctonia disease symptoms in Virginia. Additional isolates were obtained from several other states. All were characterized with respect to species characteristics as well as pathogenicity and virulence on two common cultivars of tall fescue. All isolates were pathogenic on tall fescue but there was some variability in virulence. There was consistently slightly less disease present on Crossfire II than on Kentucky 31. Experiments were also conducted to determine the impact of prior exposure to high air temperatures on the severity of disease. Preliminary data showed that one week of exposure to higher air temperatures caused an initial increase in overall turf quality, but as length of exposure increased the quality of turfgrass declined. Tall fescue plants were subjected to 0, 7, and 35 days of heat stress prior to inoculation with several isolates of R. zeae. No relationship was found between predisposing heat stress and disease severity. / Master of Science

The production of livestock in Utah is important to the economy of the state. The economic life of many communities throughout the state depends on income from livestock. Cash receipts from range livestock were $62.7 million or 38.8 percent of the total from agriculture in Utah in 1958 (18). Much land in Utah is used almost exclusively for livestock production. Of the 52.7 million acres in Utah about 78 percent is used for the production of range livestock (15). Sheep obtain approximately 86 percent and cattle 56 percent of their forage needs from range lands (15, p.28). Although there are alternative uses for some areas, grazing livestock is the only significant economic use for much range land in the state.

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The following report discusses the design and formative evaluation of a prototype for a computer-based course to teach speech acts as part of the Technology Assisted Language Learning (TALL) program. The report includes a literature review on speech acts and current methods and strategies for language teaching and instructional design. Next, there is a description of the lessons and the design process, as well as a summary of the formative evaluation. Following is the prototype of the lesson on apologies. The report concludes with a discussion of the project's limitations and suggestions for future research.

Tall fescue [Schedonorus arundinaceus (Schreb.) Dumort.] is an important forage crop in the United States and covers over 14 million ha. The presence of Neotyphodium coenophialum, an endophytic fungus in tall fescue, is associated with several disorders in grazing livestock, but also increased persistence of tall fescue. These disorders, commonly called fescue toxicosis, are responsible for large economic losses in the beef cattle industry each year. This research examined the effect of three fescue types [endophyte-infected Kentucky 31 tall fescue (E+), endophyte-free Kentucky 31 tall fescue (E-), non-ergot alkaloid-producing endophyte Q4508-AR542 tall fescue (Q)], and Lakota prairie grass (L; Bromus catharticus Vahl.) on animal response, alkaloid appearance, DMI, and copper status. Ergovaline (EV) is the most abundant ergot alkaloid in tall fescue and has previously been considered the causative toxin in fescue toxicosis. More recently it is simpler ergot alkaloids, such as lysergic acid amide (LSA) have been implicated. The objective of the first project was to evaluate animal performance and alkaloid (EV and LSA) appearance in forage and ruminal fluid of steers grazing E-, Q, E+, and L. Average daily gains were greater (P < 0.05) on E-, Q and L compared to E+, and there was a trend (P = 0.11) for gains on E- to be higher than with Q. The seasonal appearance of LSA in ruminal fluid was similar to the seasonal pattern of alkaloids in E+ forage. Ergovaline was not detectable in ruminal fluid of steers grazing E+. Alkaloids were not detectable in forage or ruminal fluid of steers grazing E-, Q, or L. The appearance of LSA in ruminal fluid of steers grazing E+ suggests that this alkaloid may contribute to fescue toxicosis. Low DMI of animals grazing E+ tall fescue is considered a key factor in decreased animal performance compared to other fescue types. The objective of the second project was to evaluate DMI of steers grazing E-, E+, Q, and L pastures using the alkane technique. Dry matter intake of steers grazing E- was greater (P < 0.001) than Q, E+, and L and DMI of steers grazing Q and E+ were similar (P > 0.10) in 2004. In 2005, DMI did not differ (P = 0.23) among fescue types. These results suggest that decreased DMI effects ADG of steers grazing E+ compared to those grazing E-, and lower DMI of Q suggests that the fescue variety Q4508 may not be the optimal variety for the incorporation on non-ergot alkaloid-producing endophytes. Reactive oxygen metabolites such as superoxide (O₂⁻) are produced by both endogenous and exogenous sources and an accumulation of these compounds can result in oxidative stress. Copper/zinc superoxide dismutase (SOD) is a Cu-based antioxidant metalloprotein that acts as a defense against oxidative stress by the scavenging of O₂⁻. <i>Neotyphodium</i>-infected tall fescue is typically lower in Cu which could potentially increase oxidative stress of animals grazing this forage. Therefore the objective of the third project was to investigate the Cu and SOD status of steers grazing E-, E+, Q, and L forages. Copper levels of all forages were below the dietary requirement (10μg Cu/g DM) of growing cattle. In 2004, steers grazing E+ exhibited lower (P <0.05) liver Cu compared to E- and Cu intake was lower (P < 0.001). Cu/Zn SOD enzymatic activity and mRNA relative expression did not differ (P > 0.10) among treatments. Copper intake of steers grazing E+ tall fescue was sufficient to maintain, but not replenish liver Cu, and SOD status did not appear compromised by grazing E+ at these Cu levels. / Ph. D.

Urban development alters the physical and chemical properties of soil which presents challenges for vegetation establishment. Compost, when applied as a soil amendment, can help to ameliorate these challenges. In field trials, we evaluated the effect of surface-applied composts and standard hydroseeding applications on changes in soil properties and turfgrass stand on a highway roadside. The short-term effects of (1) no compost application; (2) 2.5 cm compost surface mulch; (3) 2.5 cm compost application, incorporated; (4) 5.0 cm compost application, incorporated; (5) 0.6 cm compost blanket; and (6) straw mat on turfgrass establishment, quality and changes in soil properties were measured on an urban soil devoid of topsoil. In greenhouse studies, we compared the effect of depth of planting of two variously-sized turfgrass seeds in compost. The soils of the disturbed roadside and the urban soil had increased Mehlich I-extractable soil K, Mg, and P following compost application. Analysis of botanical composition on the highway roadside demonstrated that the percentage of fescue decreased with time, while weed species increased inversely in both treatments. Compost amendments on the urban soil increased turfgrass color over time, whereas turfgrass density was not affected by time. Turfgrass density was greatest in applications of a 5 cm depth compost incorporated 7-10 cm into the soil. No differences were observed in biomass harvested among treatments. Tall fescue seeds had greater germination and establishment than smaller sized bermudagrass seeds when sown below the surface of compost, regardless of depth. Composts help to regenerate topsoil-like functionality in disturbed soils by promoting vegetation establishment, including weeds, on highway roadsides and improving turf quality on urban soils. / Master of Science

The beef cattle marketing structure imposes stress on calves due to weaning, transport, commingling, and adaptation to new diets, resulting in a weakened immune systems at the height of disease risk, frequently causing bovine respiratory disease. Backgrounding programs facilitate opportunities for calves to overcome stressors by building immunity, and adapting the rumen to high concentrate diets for improved feedlot performance. Four experiments were conducted to compare backgrounding strategies and effects of supplementation frequency performance and the effects of the ruminal environment. In Exp. 1, 48 weaned steers were used to investigate the effects of transportation and supplementation frequency, while in Exp. 2, 36 heifers were used to investigate only supplementation frequency. No differences in gains were observed due to transportation stress or supplementation frequency. Weaning stress resulted in elevated (P < 0.05) creatine kinase and neutrophil:lymphocyte ratios during the first week. In Exp. 3, 48 calves were used to compare the effect of tall fescue type on performance and health. Calves on novel endophyte fescue had higher ADG (P = 0.07) than on endophyte-infected fescue. Experiment 4 investigated the changes in ruminal environment due to supplementation frequency. No differences were observed between supplementation frequencies for ruminal pH, ammonia, or VFA concentration, and DM, or CP digestibility. Therefore, the rumen maintained a hospitable environment to promote bacterial protein synthesis and fiber digestion with every 48 h supplementation. Backgrounding calves with high fiber co-product supplements or on novel endophyte fescue can enhance calf performance. / Master of Science