Call number: LD2668 .T4 1985 M62 / Master of Science

This thesis presents an investigation into the viability of Low Energy Earth Pipe Cooling Technology in providing thermal comfort in Malaysia. The demand for air-conditioning in buildings in Malaysia affects the country escalating energy consumption. Therefore, this investigation was intended to seek for a passive cooling alternative to air-conditioning. By reducing the air-conditioning demand, there would be a higher chance of Malaysia government to achieve their aim in reducing CO2 emissions to 40 per cent by the year 2020, compared to 2005 levels. The passive technology, where the ground was used as a heat sink to produce cooler air, has not been investigated systematically in hot and humid countries. In this work, air and soil temperatures were measured on a test site in Kuala Lumpur. At 1m underground, the result is most significant, where the soil temperature are 6oC and 9oC lower than the maximum ambient temperature during wet and dry season, respectively. Polyethylene pipes were buried around 0.5m, 1.0m and 1.5m underground and temperature drop between inlet and outlet were compared. A significant temperature drop was found in these pipes: up to 6.4oC and 6.9oC depending on the season of the year. The results have shown the potential of Earth Pipe in providing low energy cooling in Malaysia. A parametric study on the same experiment was carried out using Energy Plus programme. Energy Plus data agreed with the field work data and therefore, this confirms Energy Plus is reliable to investigate Earth Pipe Cooling in Malaysia. Furthermore, thermal comfort of air at the Earth Pipe outlet was analyzed and the result has shown that the outlet air is within the envelope of thermal comfort conditions for hot/humid countries

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Orientador: Kátia Luciene Maltoni / Resumo: Para recuperação de áreas de solo degradado, com exposição do subsolo, tem-se adotado a revegetação, para introdução de matéria orgânica, formação de serapilheira e recuperação da comunidade microbiana do solo. Esta, por meio das relações complexas que estabelece com o solo e as raízes das plantas contribuirão melhorando as condições edáficas, comprometidas pela degradação. As comunidades microbianas são influenciadas por variações na temperatura, umidade e atmosfera do solo, bem como pelas reduções da cobertura vegetal, disponibilidade de nutrientes, estabilidade estrutural do solo, entre outros fatores, que podem ser modificados pelo uso e degradação do mesmo. Este trabalho objetivou avaliar a recuperação do subsolo exposto, em área degradada no Cerrado, por meio do recobrimento da superfície, do levantamento da vegetação espontânea, das condições de fertilidade do solo e da atividade microbiológica. A técnica de revegetação adotada para recuperação constou de mecanização/escarificação da área (0,40 m de profundidade), incorporação de resíduos orgânico - RO (macrófitas aquáticas) nas doses 0, 16, e 32 Mg ha-1 e agroindustrial - RA (cinza), nas doses 0, 15, 30 e 45 Mg ha-1, como condicionantes do subsolo, e reintrodução da vegetação, com plantio de mudas de 10 diferentes espécies arbóreas nativas do Cerrado (espaçamento 4,0 x 5,0 m). Transcorridos 4 e 5 anos da intervenção, avaliou-se o desempenho da técnica proposta. A avaliação do recobrimento da superfície foi realizada p... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre

The need for efficient use of water resources has increased the importance of optimum soil water usage in agricultural systems. Soil temperature has been shown to be important in influencing the early development of many plant species. Many agricultural regions have suboptimal soil temperature regimes for plant growth, and some cultural practices have been shown to reduce near-surface soil temperatures. The seasonal influence of soil temperature on soil water extraction and aboveground and belowground plant growth under variable irrigation was investigated at the USU Greenville Farm in Logan, UT. Soil surface mulches and buried heat cables were used to modify soil temperature. A line-source sprinkler system provided a gradient of water application. During 1987 yields were mainly influenced by irrigation. During 1988 greater soil temperature differences resulted in significant plant growth and yield responses. Soil water depletion corresponded to soil temperature treatments during the early part of the growing seasons. Depth of maximum soil water depletion was about 20 cm deeper for warm treatments. Water uptake rates of earlier-maturing plants in warm treatments were reduced later in the season, so that cumulative seasonal soil water depletion was similar for all temperature treatments. Although depth of rooting was somewhat greater under high than low irrigation during 1988, low irrigation treatments depleted soil water to greater depth. There was no interactive response of plant growth and yield or of soil water depletion to soil temperature and irrigation treatments. Modifications were made to a computer simulation model of the soil-plant-atmosphere system in order to more mechanistically simulate plant water uptake and to include influences of soil temperature on seasonal rooting growth and soil water extraction. The model adequately simulated both the pattern and magnitude of soil temperature influences on soil water depletion, and conclusions drawn from model simulations agreed with field observations during 1987 and 1988.

Surface mining is a major industry in eastern Tennessee that removes much of the native forest. To restore the forest, reclamation practices are used. These include planting a ground cover species with native hardwoods. Competition between the ground cover and tree species for soil resources could hinder growth and decrease survival of the trees. Northern red oak (Quercus rubra) was used for this study to examine the possible effects of this competition and the relationships between root growth and soil moisture through a field and a greenhouse experiment. A field experiment was designed using four different ground cover treatments (Soldiago nemoralis, Medicago sativa, Panicum virgatum, and bare ground) with four different hardwood species. Northern red oak was measured for this study. The results showed that the site physical factors (slope position, soil temperature, and soil moisture) were not related to each other. Soil moisture varied by depth with the lower depths (46 cm to 76 cm) was much higher than the upper depths (0 to 46 cm). Root growth did not differ by treatment or percent cover. Both soil temperature and ground cover percentage increased over the growing season. Root growth showed a relationship with depth with the upper depths of soil having more roots than the lower depths. Annual rye was used as well as switchgrass, alfalfa, and bare ground treatments for a green house study. Two-year-old Northern red oak seedlings were first planted in pots and then ground covers were established and grown for 9 weeks. Then water stress was imposed over two dry down periods during which transpiration and soil moisture were measured. Root growth was measured after harvest. The results showed a relationship between transpiration and soil moisture. Soil moisture was highest in the bare ground treatment and lowest in the annual rye treatment. Fine root development of trees was greatest in the bare and alfalfa and lowest in the annual rye. Switchgrass had the second highest soil moisture and third highest fine root development. Root growth was related to both soil moisture and transpiration.

Below-ground effects during forest fires are some of the important issues forest managers consider when conducting prescribed fire programs. Heat transfer models in soil are needed to predict temperatures in soil during forest fires. Many of the heat transfer models in soil that include the effects of moisture are complex and in most cases do not have very good predictive abilities. Researchers believe that simple heat transfer models in soil that neglect the effects of moisture could have very good predictive abilities.<p>This study presents a one-dimensional numerical model of heat transfer in dry homogenous sand. Both constant and temperature dependent thermal properties of the sand were used in order to determine which had better predictive abilities. The constant thermal properties model was also extended to a model of two-layer dry soil. A computer code written in Fortran was used to generate results from the model. A number of experiments were conducted with dry sand to validate the model. A comparison of the numerical and experimental results indicated that the temperature dependent properties model had better predictive abilities than the constant properties model. The models were found to do a good job of predicting temperature profiles and depth of lethal heat penetration at heat fluxes indicative of forest fires.<p>Experiments were also conducted to determine the effect of moisture on temperature profiles and the depth of lethal heat penetration in sand and the effect of inorganics on the spread rate of smoldering combustion in peat moss. An experimental correlation of the effects of inorganic content on the spread rate of smoldering combustion in peat moss was developed. Additionally, laboratory methods of validating models of heat transfer in soil were developed with the aim of limiting the dependence on full scale testing. Specifically the use of the cone calorimeter for validating numerical models of heat transfer in soil and the responses of forest floor soil and laboratory created soil samples to heat input were compared. The results indicated that the laboratory created soil did a very good job of mimicking the heat response of the forest floor soil with a maximum difference in lethal heat penetration of 4%.

This thesis has investigated the possibility of improved soil temperature modeling using an updated version of an existing soil temperature model frequently used in catchment scale biogeochemical modeling. Future (2061-2090) snow dynamics and soil temperature was projected using ensemble of bias-corrected regional climate models (RCM). Effects over a north-south gradient of Sweden were analyzed using the four Swedish Integrated Monitoring (IM) catchments as study sites. Model calibration was applied on the study sites using daily observations of soil temperature for 1996-2008. The calibrated models were able to simulate soil temperature at different depths in the soil profile in a very accurate way in all IM sites. The lowest validation NS-value (objective criterion used for measuring goodness of fit) recorded in the study was 0.93. Even though the overall model performances were good, the simulations had problem of duplicating some of the winter temperatures at the northernmost site, Gammtratten. Whether the updated soil temperature model offered an improvement of the existing model is therefore debatable. The future simulations showed increasing soil temperatures at all study sites on annual basis, more in the south than in the north. Annual soil temperatures were projected to increase by 1.31 – 2.33 °C for the different study sites. Winter soil temperatures were clearly higher than during 1996-2008 for the two southernmost sites, whilst Gammtratten in the north, had colder winter soil temperatures. At the midmost catchment, winter soil temperatures were quite similar to that of the test period. Whether the cold winter soil temperatures at Gammtratten were a result of snow loss was ambiguous. The results from the future simulations showed the complexity of predicting soil temperature and strengthened the conclusion among scientists that any general assumptions of future soil temperature based on e.g. air temperature cannot be done. / Det här examensarbetet har undersökt möjligheterna till förbättrad modellering av marktemperaturer genom införandet av en uppdaterad version av en tidigare modell, frekvent använd vid biokemisk modellering på avrinningsområdesnivå. Vidare har framtida (2061-2090) snödynamik och marktemperaturer simulerats genom att en ensemble av bias –korrigerad klimatdata används för att driva modellen. Nutida (1996-2008) klimatdata, samt marktemperatursdata för kalibrering och validering av modellen, tillhandahölls från de fyra platser som ingår i det Svenska miljöövervakningsprogrammet (IM). Dessa platser kom att utgöra en syd-nordlig gradient, längs vilken resultaten analyserades.   Det generella omdömet från kalibreringen av modellen var att den kunde erbjuda en bra representation av verkliga förhållanden i fråga om marktemperatur. Det lägsta NS-värdet (objektivt kriterium använt för att mäta modellens passningsgrad) som uppmättes under valideringen var 0,93, vilket ansågs vara mycket högt. Dock hade modellen svårigheter att efterlikna verkliga markförhållanden vid Gammtratten under vintermånaderna, vilket föranledde slutsatsen att vidare undersökningar behöver göras för att kunna fastställa om modellen utgör en förbättring av den tidigare existerande versionen.   De framtida simuleringarna visade högre årliga marktemperaturer i jämförelse med dagen värden, särskilt i söder. Baserat på simuleringarna är det troligt att framtida marktemperaturer kommer att vara mellan 1,31 och 2,33 °C högre än idag. Beträffande säsongsmässig variation var maktemperaturerna under vintern högre än dagens värden för de två sydliga platserna medans de var lägre för den nodligaste platsen (Gammtratten). Huruvida de kallare simulerade marktemperaturerna vid Gammtratten var en konsekvens av ett mindre isolerande snötäcke var tvetydigt. Resultaten från de framtida simuleringarna har visat på komplexiteten i att förutspå framtida marktemperaturer och har stärkt uppfattningen om att några generella slutsatser om vad t.ex. högre lufttemperaturer kommer få för konsekvenser för framtida marktemperaturer inte kan göras.

Below-ground effects during forest fires are some of the important issues forest managers consider when conducting prescribed fire programs. Heat transfer models in soil are needed to predict temperatures in soil during forest fires. Many of the heat transfer models in soil that include the effects of moisture are complex and in most cases do not have very good predictive abilities. Researchers believe that simple heat transfer models in soil that neglect the effects of moisture could have very good predictive abilities.<p>This study presents a one-dimensional numerical model of heat transfer in dry homogenous sand. Both constant and temperature dependent thermal properties of the sand were used in order to determine which had better predictive abilities. The constant thermal properties model was also extended to a model of two-layer dry soil. A computer code written in Fortran was used to generate results from the model. A number of experiments were conducted with dry sand to validate the model. A comparison of the numerical and experimental results indicated that the temperature dependent properties model had better predictive abilities than the constant properties model. The models were found to do a good job of predicting temperature profiles and depth of lethal heat penetration at heat fluxes indicative of forest fires.<p>Experiments were also conducted to determine the effect of moisture on temperature profiles and the depth of lethal heat penetration in sand and the effect of inorganics on the spread rate of smoldering combustion in peat moss. An experimental correlation of the effects of inorganic content on the spread rate of smoldering combustion in peat moss was developed. Additionally, laboratory methods of validating models of heat transfer in soil were developed with the aim of limiting the dependence on full scale testing. Specifically the use of the cone calorimeter for validating numerical models of heat transfer in soil and the responses of forest floor soil and laboratory created soil samples to heat input were compared. The results indicated that the laboratory created soil did a very good job of mimicking the heat response of the forest floor soil with a maximum difference in lethal heat penetration of 4%.

Thesis (Ph. D.)--University of California, Riverside, 2009. / Includes abstract. Available via ProQuest Digital Dissertations. Title from first page of PDF file (viewed March 16, 2010). Includes bibliographical references. Also issued in print.