This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

Στην διπλωματική αυτή εργασία παρουσιάζονται οι πτυχές σχετικά με τον έλεγχο του φωτισμού στα θερμοκήπια με τη χρήση των φακών Fresnel ως διαφανή καλύμματα καθώς και τα αποτελέσματα του συνδυασμού των γραμμικών φακών Fresnel με θερμικά (Τ), φωτοβολταικά (PV) ή υβριδικά φωτοβολταϊκά/θερμικά (PV/T) συστήματα μετατροπής της πλεονάζουσας ηλιακής ακτινοβολίας εντός του θερμοκηπίου σε ηλεκτρική ενέργεια και θερμότητα. Τα συστήματα αυτά μελετούνται σχετικά με την απόδοσή τους στην κάλυψη των θερμικών και ηλεκτρικών αναγκών μιας χαρακτηριστικής θερμοκηπιακής μονάδας, δίνοντας κατ / We present aspects and results concerning irradiation control in greenhouses by using glass type fresnel lenses as transparent covering material. We also present results of the combination of the fresnel lenses with thermal (T), photovoltaic (PV) or hybrid photovoltaic/thermal (PV/T) type absorbers to convert the surplus of the solar radiation inside the greenhouse into electricity and heat. The suggested systems are studying regarding their performance in covering thermal and electrical needs of a typical greenhouse unit, giving also the estimated benefits.

Tyrimų tikslas – ištirti galimybę panaudoti tiesioginę spinduliuotę džiovinamos medžiagos ir džioviklio įkaitimui džiovinant grūdus Lietuvos sąlygomis . Lietuvoje nuimtų grūdų drėgnumas dažniausiai viršija kondicinį, todėl siekiant išvengti kokybės nuostolių juos būtina nedelsiant konservuoti. Darbe apžvelgti grūdų fizinių savybių pokyčiai džiovinimo metu, plačiau analizuojama tiesioginės saulės spinduliuotės panaudojimas Lietuvos sąlygomis džiovinant grūdus su saulės kolektoriais. Ištirtas tiesioginės saulės spinduliuotės poveikis grūdams ir džioviklio paruošimui. Nustatyta, kad tiesioginė saulės spinduliuotė sutrumpina grūdų džiovinimo laiką ir sutaupo energiją naudojamą grūdų džiovinimui. Nustatyta saulės kolektoriaus pasvirimo kampo priklausomybė nuo spindulių kritimo kampo, džiovinimo greičio priklausomybė nuo oro filtracijos greičio ir grūdų drėgnio. / Purpose of the study - research the possibility of using direct solar radiation to heat desiccant material and siccative when drying grain in Lithuanian weather conditions. In Lithuania, humidity of harvested grain is generally higher than conditioned. To avoid loss of quality grain should be cured immediately. This paper reviews changes in physical properties of grain during drying. A wider analysis of use of solar collectors for drying grain in Lithuania using direct solar radiation is also given. Direct solar radiation impact on grain and preparation of dryer has been investigated. It has been found that direct solar radiation reduces the drying time and lowers energy costs when drying grain. Dependence of solar collector tilt angle and solar radiation incidence angle was established. Drying speed relation to air filtration rate and grain moisture has also been found.

This work comprises a radiometric study of Durban‟s solar resource, utilizing data from the Howard College campus of the University of KwaZulu-Natal (UKZN), and the Solar Thermal Applications Research Laboratory (STARlab) at Mangosuthu University of Technology (MUT), located 17 km away. The study has three aims: first to establish a solar radiometric monitoring network for the greater Durban area, comprising the UKZN Howard College and Westville stations, and the STARlab facility at MUT. The UKZN Westville station is under refurbishment and should be operational by the end of 2011. Data from this station are not included in the study. The instrumentation and acquisition software in use at Howard College and STARlab are described. The stations record global horizontal irradiance (GHI), direct normal irradiance (DNI) and diffuse horizontal irradiance (DHI), measured by an unshaded pyranometer, a normal incidence pyrheliometer and a pyranometer shaded with a stationary band respectively. Second, to test a number of existing radiometric models against measured data gathered at the stations. Radiometric models assist in estimating missing components of radiation at stations that do not measure all three components separately, for reasons of cost. The models investigated included Erbs et al. (1982), Orgill and Hollands (1977), Reindl et al. (1990), Boland et al. (2001), and Skartveit and Olseth (1987) and correction models by Drummond et al. (1956), Le Baron et al. (1990), Batlles et al. (1995), and Muneer and Zhang (2000) to correct the shadow band effect. Third, to compare data from the two operational stations and to investigate potential spatial differences in sun strength arising from micro-climate effects in the greater Durban area. This takes the form of a statistical analysis of the differences in radiometric data recorded simultaneously at the UKZN and STARlab stations. The study found that the recorded difference in GHI over one year was 0.72%, which lies within the instrument measurement accuracy. Therefore no measurable radiometric differences due to microclimate could be detected and, for the period in which data were collected, measurements from Howard College could be used to estimate irradiance patterns for MUT, and vice versa. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2011.

In order to improve the water situation in rural areas of Bangladesh, a research group at the University of Dhaka has been developing low cost domestic methods to remove pathogens from surface water through pasteurisation using free solar energy. Pasteurisation is a process in which water is heated to approximately 60 °C and maintained for about 30 minutes to destroy pathogens. In these methods, the water is also exposed to UV-light from the sunshine, which causes destruction of diarrhoeal pathogens at temperatures somewhat lower than required in normal pasteurisation. However, despite many advantages these devices need to be installed for each time of use. Recently, a semi-permanent device has been developed which is expected to be more user friendly. The objective of this Master thesis has been to study and optimize the low cost semi-permanent device that can deliver safe drinking water to people in rural areas. Two test devices were constructed to determine the most effective treatment e.g. temperature, time, solar radiation, user-friendliness and cost. To replicate the results from the solar heating tests a model, based on the solar radiation and convective heat loss from the device, was used. The model was also able to determine the time duration at a certain solar radiation level to estimate when the water is safe to drink. The results revealed that the performance of the device depends on thickness of the insulation and thickness of the air gap. This is because the most important factors to achieve safe drinking water are solar radiation and time. The modelling indicated that the measured water temperature corresponds well with the calculated water temperature and also showed that the lowest required solar radiation is 390 W/m2 to reach drinking water criteria, at an air temperature of 25 °C. A study of microbiology showed that the semi-permanent low cost device could purify surface water to a safe level.

Geoengineering is the intentional alteration of the Earth’s climate system. The international Geoengineering Model Intercomparison Project (GeoMIP) seeks to identify the potential benefits and side effects of geoengineering on the Earth's climate. This thesis examines the first two experiments from the contribution of the Canadian Centre for Climate Modelling and Analysis to GeoMIP. In the first experiment (G1), atmospheric carbon dioxide concentrations are quadrupled and the solar constant is reduced to offset the increased greenhouse gas forcing. In the second experiment (G2), atmospheric carbon dioxide concentrations are increased at the rate of 1% per year and the solar constant is incrementally reduced to offset the greenhouse gas forcing. In concert with these experiments, results from two other experiments were analyzed, one in which the atmospheric greenhouse gas concentrations are quadrupled one in which they are increased at the rate of 1% per. The results obtained are in broad agreement with earlier work, showing that solar radiation management geoengineering schemes can prevent an increase in mean global surface temperature as atmospheric carbon dioxide concentrations increase. Though the mean global temperature remains constant while geoengineering is employed, there are regional and zonal differences from the control climate, with high latitude warming and cooling in the tropical and subtropical regions. In particular, the meridional temperature gradient is reduced compared to that of the control climate. The G2 experiment was very similar to the G1 experiment in terms of the spatial surface temperature changes, though the changes seen in the G2 experiment were less pronounced and the regions of statistical significance were smaller. During the geoengineering period, seasonal changes and a statistically significant decrease in global precipitation, particularly over the ocean were apparent in the G1 run. As with temperature, the spatial pattern of precipitation changes during the geoengineering period for G2 are similar to the same period in G1, but reduced in magnitude. However, most of the spatial changes to precipitation in the G2 experiment during geoengineering deployment fail to be statistically significant. Following geoengineering termination, the G1 experiment responds rapidly, with surface and ocean temperatures, NH and SH summer sea ice volume, AMOC transport volume and global precipitation following the same time evolution and reaching those same values found in the 4 × CO2 experiment’s first 10 years. Following geoengineering failure, the G2 run also experiences rapid climate change in all of the variables studied, but does not approach the first 10 years of the 1%CO2yr-1 experiment, because the forcings are quite different in the two runs. Taken together, these results suggest that, while geoengineering to reduce incoming solar radiation could offset the global temperature increase due to increased atmospheric greenhouse gas concentrations, there would be regional warming and cooling, as well as both global and regional impacts on the hydrological cycle. These results also suggest that, should geoengineering suddenly stop, the Earth’s climate would react immediately, with rapid changes in nearly all of the climate variables examined. / Graduate

Thesis (Ph. D.)--University of Hawaii at Manoa, 2004. / Includes bibliographical references (leaves 198-219). / Also available by subscription via World Wide Web / xvii, 219 leaves, bound ill., some col. 29 cm

This study set out to examine the levels of galactic cosmic radiation exposure to Australian aircrew during routine flight operations, with particular attention to the high southern latitude flights between Australia and South Africa. Latitudes as high as 65?? South were flown to gain the data and are typical of the normal flight routes flown between Sydney and Johannesburg on a daily basis. In achieving this objective it became evident that suitable commercially available radiation monitoring equipment was not readily available and scientific radiation monitors were sourced from overseas research facilities to compliment my own FH4lB and Liulin monitors provided by UNSW. At the same time it became apparent that several predictive codes had been developed to attempt to model the radiation doses received by aircrew based on flight route, latitudes and altitudes. Further, it became apparent that these codes had not been subjected to verification at high southern latitudes and that they had not been validated for the effects of solar particle events. Initially measurements were required at the high latitudes followed by mid-latitude data to further balance the PCAIRE code to ensure reasonableness of results for both equatorial and high latitudes. Whilst undertaking this study new scientific monitors became available which provided an opportunity to observe comparative data and results. The Liulin, QDOS and a number of smaller personal dosimeters were subsequently obtained and evaluated. This appears to be the first time that such an extensive cross comparison of these monitors has been conducted over such a wide range of latitudes and altitudes. During the course of this study a fortuitous encounter with GLE 66 enabled several aspects of code validation to be examined, namely the inability of predictive codes to estimate the increased dose associated with a GLE or the effects of a Forbush decrease on the code results. Finally I review the known biological effects as discussed by numerous authors based on current epidemiological studies, with a view to high-lighting were the advent of future technology in aviation may project aircrew dose levels.

Thesis (Ph.D.)--McMaster University (Canada), 1991. / Source: Dissertation Abstracts International, Volume: 53-01, Section: B, page: 0178. Supervisor: John A. Davies.

Thesis (Ph.D.)--McMaster University (Canada), 1996. / Source: Dissertation Abstracts International, Volume: 57-10, Section: B, page: 6146. Adviser: M. K. Woo.