Forest soil is an important source of atmospheric CO2. Emission of CO2 from soil is the result of respiration of plant roots and soil organisms (Autotrophic and Heterotrophic respiration). This soil CO2 emission has a variation throughout the year with maximum emissions being in the summer. However, the seasonal variation affected by the external factors is not fully known. The aim of this thesis is to analyze a relationship between concentration of CO2 in the soil-atmosphere and CO2 emissions to the aboveground atmosphere. When knowing the relationship between CO2 concentration in the soil-atmosphere and the emission of CO2 from the soil atmosphere, a function (equation) can be established. Usually, the best fit is considered to establish the relationship. With the equations obtained, it is possible to calculate CO2 emissions using data different projects, where only soil-atmosphere CO2 concentrations were determined. Using the relationships, emissions rates in different soil types and in forest transect have been analyzed for a large number of samples. The effect of nitrogen deposition on CO2 emissions and seasonal variation of CO2 emission has also been studied. The sampled sites chosen for this study were located in different parts of Southern Scandinavia and Germany. A closed chamber was used to measure CO2 emission from soil. Soil CO2 concentrations were measured at every station and the equations were established. Finally, these relationships were used for analyses and comparison of the sites. An equation (best fit) obtained was used to calculate the emission values of CO2. The soil texture had a great influence on the CO2 from the soil besides the atmospheric pressure and temperature variations during the seasons. It is concluded that, therefore the soil texture and had a great influence on the CO2 emission from the soil besides the atmospheric pressure and temperature variations during the season. When knowing the equation between CO2 concentration and emission for a special type of soil, it is possible to estimate emissions based on CO2 concentrations. Therefore large scale sampling of CO2 concentrations could be done and this will facilitate the inventories carried out in e.g. global change studies.

The topic of my thesis is the design of a kindergarten in Rajhrad. The building is one storey with a flat roof. In the middle of the building there are technical facilities, a kitchen, a director's office and facilities for staff. On the sides there are classrooms with bathrooms and cloakrooms. The load-bearing masonry is designed of Heluz ceramic blocks. The perimeter masonry is insulated with the ETICS contact insulation system. The roof structure is made of prefabricated floor slabs SPIROLL. The building is covered by a green flat roof. The building will be heated by a gas condensing boiler. It will have an air handling unit located on the roof along with photovoltaic panels. Intelligent LED lighting will be deployed throughout the building. The third part deals with the comparison between masonry construction and the more environmentally friendly clay construction. Specifically, it compares the CO2 production of masonry and clay construction of the same building using the SBToolCZ methodology. The results obtained showed that the clay building produces approximately 30% less CO2 than the masonry building. I created my thesis using ArchiCAD and DEKsoft software.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第21312号 / 農博第2297号 / 新制||農||1065(附属図書館) / 学位論文||H30||N5146(農学部図書室) / 京都大学大学院農学研究科地域環境科学専攻 / (主査)教授 舟川 晋也, 教授 縄田 栄治, 教授 北山 兼弘 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

Power dispersion within oil injected screw air compressors : The PhD-work shows the power dispersion within the oil- and air circuits of oil injected screw air compressors for the working pressures (Pd), where Pd has been tested for Pd ≤ 8,5 bar (a) and Pd ≤14,0 bar(a) respectively. The executed test runs with mineral oil have further confirmed the suppliers quoted performance data within stated tolerances. For comparison of the compressor performance with type of lubricant, the performance tests have been repeated with the four most common types of lubricants, which today are commercialised for screw air compressors. The selected lubricants hold the same cinematic viscosity (ISO VG 46), but the lubricants diverge in question of solubility of air and in formation of air bubbles during the compression cycle. These phenomenas confirm deviations in prevailing viscosity in the oil film and demonstrate that the performance data vary slightly with selected type of lubricant. The tests have proven that the air, which dissolve in the lubricant during the compression cycle will not degas during the resting period in the air/oil receiver, nor will the miniscule air bubbles degas due to their low ascending speed. This means that the content of dissolved air and air bubbles in the oil in the receiver becomes the most elevated within the system and where the temperature is the highest within the compressor cycle. Further is the resting period of the oil in the receiver extreme long in relation to the over all operating cycle of the oil. The conclusion is that the destruction (oxidation) of the oil is taking place in the oil/air receiver and nowhere else within the system. To counteract the oxidation and other destructive processes in the oil circuit « additives » are introduced in the oil. So are e.g. anti-oxide additives reducing the formation of peroxides and are by this reducing the oxidation velocity of the oil until the additives have been consumed. These additives are reducing the oxidation velocity of the lubricants, but will as well, due to the increased polarity caused by the additives, increase the content of dissolved water in the oil. However, this increased content of dissolved water is (strongly) reducing life of the roller bearings. The measured quantities of dissolved water in the lubricants (after the executed tests) have been compared with achieved bearing life from tests executed by others. The PhD work is finally summarizing that the only method to strongly reduce the destruction of the lubricant is to immediately separate off the oil from the compressed air at exit of the compressor. In addition, the today's « dumped » power in the oil cooler can be recovered to increase the available pneumatic power by some 25-30%. Assumingly, this increase in working temperature of the pneumatic air will, in addition increase the efficiency in applied pneumatic tools.

<div>A growing global population and improved standard of living in developing countries have resulted in an unprecedented increase in energy demand over the past several decades. While renewable energy sources are increasing, a huge portion of energy is still converted into useful work using heat engines. The combustion process in diesel and petrol engines releases carbon dioxide and other greenhouse gases as an unwanted side-effect of the energy conversion process. By improving the efficiency of internal combustion engines, more chemical energy stored in petroleum resources can be realized as useful work and, therefore, reduce global emissions of greenhouse gases. This research focused on improving the thermal efficiency of opposed-piston engines, which, unlike traditional reciprocating engines, do not use a cylinder head. The cylinder head is a major source of heat loss in reciprocating engines. Therefore, the opposed-piston engine has the potential to improve overall engine efficiency relative to inline or V-configuration engines.</div><div><br></div>The objective of this research project was to further improve the design of opposed-piston engines by using computational fluid dynamics (CFD) modeling to optimize the engine geometry. The CFD method investigated the effect of intake port geometry and exhaust piston lead angle on the scavenging process and in-cylinder turbulence. After the CFD data was analyzed, scavenging efficiency was found insensitive to transfer port geometry and exhaust piston lead angle with a maximum change of 0.61%. Trapping efficiency was altered exclusively by exhaust piston lead angle and changed from 18% to 26% as the lead angle was increased. The in-cylinder turbulence parameters of the engine (normalized swirl circulation, normalized tumble circulation, and normalized TKE) experienced more complex relationships. All turbulence parameters were sensitive to changing transfer port geometry and exhaust piston lead angle. Some examples of trends seen during the analysis include: an increase in normalized swirl circulation from 0.01 to 4.45 due to changes in swirl angle, a change in normalized tumble circulation from -28.52 to 21.11 as swirl angle increased, and an increase in normalized tumble circulation from 14.20 to 33.68 as exhaust piston lead angle was increased. Based on the present work, an optimum configuration was identified for a swirl angle of 15°, a tilt angle of 10°, and an exhaust piston lead angle of 20°. Future work includes expanding the numerical model’s domain to support a complete cylinder-port configuration, adding combustion products to the diffusivity equation in the UDF, and running additional test cases to describe the entire input space for the sensitivity analysis.<br>