Dissertations / Theses on the topic 'NATURAL SUNLIGHT'

In his book Ritual House, Ralph Knowles states, "The houses we inhabit, the cities surrounding our houses, even the clothes we wear - all are shelters we erect against the elements. But they are also manifestations of ancient rituals, developed in response to nature's rhythms" (2006). Implicit within this quote is the importance of nature's rhythms in our lives, particularly those related to the movement of the sun. Many built environments have no connection to the exterior. Those who work in these spaces are disconnected from these natural rhythms and often experience detrimental physiological effects. However, technology has the potential to reintroduce aspects of natural rhythms into built environments. This research crossed disciplinary boundaries separating architecture, engineering, psychology, and building science during the design of an architectural intervention for an interior workspace known as the Sandbox, at Virginia Tech. The design proposal includes skylights that combine Photovoltaic-integrated glazing with LED lighting to create conditions that stimulate the occupants while connecting inside to out. To reestablish a connection to natural rhythms the BIPV energy monitoring is used during the day to record variations in solar radiation which at night are played back through intensity and color variations of LED lighting. The effect of the LED lighting was compared with the sunlight entering through the skylights using quantitative analysis methods and qualitative visual comparison tools including time lapse photos and videos. The research merges architectural design, lighting technology and BIPV to demonstrate a proof-of-concept for the reintroduction of natural rhythms into built environments.
Master of Science

Results are reported from a series of experiments to determine the effects of certain environmental factors, namely, sunlight, temperature and , salinity on the survival of selected enteric bacteria which are of public health importance either as indicators of faecal pollution or The survival of the as pathogens. starved organisms in seawater and in freshwater microcosms exposed to artificial and natural sunlight, and in the dark, at a range of temperatures was investigated. An acridine orange direct viable count (AODVC) using an epifluorescent microscope was employed in addition to selective and non-selective cultural methods for estimation of decay rates of the test bacteria. The use of the AODVC allowed enumeration of those bacteria which respond to the stresses of the natural environment by entering into a viable but non-culturable form. These otherwise would not be detected, as they are, by definition, non-culturable using traditional enumeration techniques based upon the production of visible signs of growth. Two strategies were employed by the organisms in response to the unfavourable conditions. Prior growth of those members of the Enterobacteriaceae in a nutrient-poor medium before inoculation into the microcosms allowed adaptation of the cells to low nutrient concentrations, thus extending survival and resulting in higher resistance to other stresses such as visible light. This extension was, however, only temporary, the ultimate fate of the bacteria being death. Enterococci were particularly sensitive to low nutrient concentrations and died very rapidly in the light. All bacteria tested were able to adopt the viable but non-culturable strategy in the dark as a temporary measure, though it was only a matter of time before viability as well as culturability was also lost. This included enterococci, for which an AODVC using the antibiotic ciprofloxacin was developed by modifying the original nalidixic acid method. Responses of bacteria in the dark were influenced by temperature. Bright natural sunlight produced rapid death in bacteria exposed in seawater microcosms, a result of the synergistic interaction of salinity, UV light and possibly temperature too, whereas the presence of humic acids in freshwater afforded some protection to the cells by absorbing the damaging UV component of sunlight. Low intensities of UV and visible light typical of those found below the surface of water may induce bacteria to evolve towards a viable but non-culturable form.

Due to their potential health impact on human beings and ecosystems, persistent trace organic compounds (TOrCs) have aroused concern from both the public and professionals. In particular, the discharge of pharmaceuticals, endocrine disrupters, disinfection byproducts and other TOrCs from wastewater treatment plants into the environment is an area of extensive current research. This work studies the fate and treatments of TOrCs, with emphases on advanced oxidation processes (AOPs). This work presents predicted removal efficiencies of a variety of engineered and natural processes for 55 frequently encountered TOrCs in treated wastewater, based on previously reported data and using existing predictive models. Correlations between physicochemical and biological properties of TOrCs and treatment performance were explored. Removal of TOrCs in all processes investigated in this study was found to be sensitive to matrix effects. Heuristic guidelines for selection of sequenced treatment processes for TOrCs management were established. A field reconnaissance of natural process of TOrCs was conducted by analyzing the occurrence and fate of a suite of TOrCs, as well as estrogenic activity in water and sediments in the Santa Cruz River, an effluent-dependent stream in Tucson, Arizona. Some TOrCs, including contributors to estrogenic activity, were rapidly attenuated with distance of travel in the river. TOrCs that have low biodegradability and low octanolwater partitioning coefficients were less removed. Results of independent experiments indicated potential indirect photodegradation of estrogenic compound by reactive species generated from photolysis of effluent organic matter. Utilizing advanced oxidation processes (AOPs) as tertiary water and wastewater treatment is an option to prevent discharge of TOrCs into the environment. Compared to conventional AOPs, the ability of generating hydroxyl radicals (•OH) without additional doses of hydrogen peroxide (H2O2) or ozone makes ultraviolet (UV) photolysis of ferric hydroxo complexes a novel AOP, especially in acidic environments. A Fe(III)/UV254 kinetic model, which combines Fenton-like mechanism, and photolyses of Fe3+, FeOH2+ and H2O2 was proposed and experimentally validated to predict Fenton-like and H2O2 direct UV254 photolysis scenarios, individually. Nevertheless, the model underestimated the ferrous ion development during Fe(III)/UV254 photolysis, perhaps due to the overprediction of the oxidation of Fe2+ by •OH. The UV/H2O2 AOP was also studied in this work. A predictive kinetic model was developed to evaluate process efficiency of oxidation of p-cresol by UV/H2O2 photolysis based on a complete reaction mechanism, including reactions of intermediates with •OH. Results of this study highlight the significance of consideration of radical scavenging effects by the byproducts from oxidation of organic matter in model prediction performance.

Cryptophlebia leucotreta granulovirus (CrleGV-SA) is a baculovirus specifically pathogenic to the citrus pest false codling moth, Thaumatotibia leucotreta. CrleGV- SA is formulated as a commercial biopesticide, Cryptogran® (River Bioscience, South Africa). The virus has a stable, proteinaceous crystalline occlusion body (OB) that protects the nucleocapsid. The major limitation to the use of baculoviruses is their susceptibility to the ultraviolet (UV) component of sunlight, which rapidly and greatly reduces their efficacy as biopesticides. The UVA and UVB components are the most destructive to biological organisms. To date no publication has reported the effect of UV on the structure and virulence of CrleGV, or the effectiveness of the OB as a UV protectant. In this study the effect of UV irradiation on the structure and infectivity of pure CrleGV-SA and Cryptogran® was investigated using scanning electron microscopy (SEM), Raman spectroscopy, qPCR, and bioassays. The project included laboratory and field studies. In the laboratory, CrleGV-SA and Cryptogran® were exposed to either UVA or UVB for periods of 24 hours to 7 days before analysis. In the field, Cryptogran® was applied to trees in a citrus orchard with young fruit. The fruit were collected from 24 hours to 28 days after application and bioassays conducted to assess the effect of sunlight over time on virus structure and efficacy when applied to the northern or southern sides of the trees. No surface morphological changes to the virus were detected using SEM. However, small compositional changes were detected by Raman spectroscopy. qPCR and bioassays demonstrated that UV irradiation damaged the viral DNA, greatly reducing the infectivity of pure CrleGV-SA and Cryptogran®. Exposure to UVB reduced the virulence of the virus more than UVA. The field studies revealed that the activity of CrleGV-SA decreased more on the northern side of the trees than on the southern side.

A humid subtropical climate is characterized by a predominant partly cloudy sky, which increases the intensity of solar radiation, and makes shade an essential requeriment. Thus, the indoor daylighting environment may depend more on reflected light than on direct light. Planning the shape of the surfaces is an important means of making full use of the reflected sunlight. In this regard, shading devices can be designed that just obstruct the view of the sky enough to provide shade, by reflecting the sunlight for the environment, and reducing this loss. The aim of this doctoral research is to study the performance of shading devices in classrooms with regard to their luminous power when capturing reflected sunlight in Maceió, so as to determine the potential use of sunlight in these elements. Three variables of these devices were defined for this: the number of pieces, specularity and reflectance of the surfaces devices. The resulting models from the combination of these variables were analyzed to calculate the reflected sunlight efficiency, rate employed in this research. The software used for the computational simulations of these models was TropLux. Statistical analyses were conducted to determine which variables had the greatest impact on the reflected sunlight efficiency and to relate the rate to the daylighting performance through indicators of availability, distribution and the maintenance of illuminance inside the environment: these included the annual average illuminance and uniformity rate, and spatial daylight autonomy. The results showed that the reflectance of the devices is the variable that has the most positive influence on the reflected sunlight efficiency, and is able to increase the rate by up to 142%. The annual average illuminance and the spatial daylight autonomy were positively related to the efficiency and the defined parameterization also led to an increase of their values. With regard to the distribution of illuminances, the variations of the analyzed parameters resulted in a reduction of the uniformity rate in most of the cases studied. The increase in specularity and specular reflectance in the models facing east reduced the rate by up to 34% and 41%, respectively. Increasing the number of components in the system devices installed in lateral openings, only provides a valid solution for the increase of the illumination when these elements have a high reflectance, especially specular. This represents a more efficient strategy in the case of the north facade. Among the analyzed models, in the systems with the largest number of components, and where the surface finishing process provides specular reflection, there is a greater use of sunlight in the reflected form. The use of light colors, such as white, beige and yellow, also benefit the use of sunlight, especially if they are used in materials with specular reflection. In contrast, the high reflectances resulted in a reduction of the uniformity of illumination in the environment. From the results of the studies carried out into reflected sunlight efficiency, it can be stated that it is possible to increase the use of sunlight through the variation of certain shading devices and, hence, to bring benefits by making daylighting available in the environment.
O clima quente e úmido caracteriza-se pelo predomínio do céu parcialmente nublado, o que torna intensa a radiação solar, impondo a necessidade de sombreamento. Assim, a iluminação natural no interior do ambiente pode depender mais da luz refletida do que da luz natural direta. Planejar a forma das superfícies é um importante recurso para o aproveitamento da luz solar refletida. Neste sentido, dispositivos de sombreamento podem ser projetados para obstruir a visão do céu apenas o necessário para o sombreamento, refletindo a luz solar para o ambiente e minimizando essa perda. O objetivo geral desta pesquisa de doutorado é estudar o desempenho de dispositivos de sombreamento em salas de aula com relação à eficiência luminosa na captação da luz solar refletida, em Maceió, a fim de que seja identificado o potencial de aproveitamento da luz solar desses elementos. Para isso foram definidas três variáveis desses dispositivos: número de peças, especularidade e refletância das superfícies dos brises. Os modelos resultantes da combinação dessas variáveis foram analisados quanto à eficiência da luz solar refletida, índice proposto nesta pesquisa. O programa utilizado para as simulações computacionais desses modelos foi o TropLux. Análises estatísticas foram desenvolvidas a fim de identificar as variáveis de maior impacto para a eficiência da luz solar refletida e relacionar o índice ao desempenho da iluminação, através de indicadores de disponibilidade, distribuição e manutenção da iluminância no ambiente: iluminância média anual, uniformidade média anual e autonomia de luz natural espacial. Os resultados mostraram que a refletância dos dispositivos é a variável que mais influencia positivamente a eficiência da luz solar refletida, chegando a incrementar em até 142% o índice. A iluminância média anual e a autonomia de luz natural espacial foram relacionados positivamente à eficiência e a parametrização definida também contribuiu para a ampliação dos seus valores. Quanto à distribuição de iluminâncias, a variação dos parâmetros analisados resultou em redução do índice de uniformidade, na maioria dos casos estudados. O aumento da especularidade e da refletância especular em modelos voltados para Leste reduziram o índice em 34% e 41%, respectivamente. Aumentar o número de peças em sistemas de dispositivos inseridos em aberturas laterais apenas corresponde a uma solução válida para o incremento da iluminação quando tais elementos possuem alta refletância, sobretudo especular. Tal medida representa uma estratégia mais eficiente no caso da fachada Norte. Entre os modelos analisados, os sistemas com maior número de peças, cujo acabamento das superfícies proporciona reflexão especular, são capazes de promover maior aproveitamento da luz solar na forma refletida. O uso de cores claras, como branco, creme e amarelo, também favorece o aproveitamento da luz solar, sobretudo se forem empregadas em materiais com reflexão especular. Por outro lado, altas refletâncias resultaram em redução da uniformidade da iluminação no ambiente. A partir dos resultados dos estudos de eficiência da luz solar refletida desenvolvidos, pode-se afirmar que é possível ampliar o aproveitamento da luz solar através da variação de determinadas características de dispositivos de sombreamento e, consequentemente, trazer benefícios para a disponibilidade de iluminação no ambiente.

ZnO nanoparticles were synthesized by using wet chemical route directly from an aqueous solution of zinc acetate dehydrate[Zn(C2H3O2)2.2H2O] and in the presence of sodium dodecyl sulfate (SDS).A comparative study was doneon optical properties and photocatalytic activity of ZnO synthesized using two different precipitating agentsof NaOH and NH4OH. The as synthesized Zn(OH)2powders were calcined at a temperature of 650?C.The materials prepared were characterized by UV-visible spectroscopy and photoluminescence (PL) studies.The photocatalytic activity were evaluated by using theRhodamin B (RhB) as contaminants. The RhB dye degradation was done over the surface of ZnO under natural sunlight illumination to elucidate the photo-catalytic activity. A series of experiments were carried out to study the influences of irradiation time, catalyst concentration,and initial concentration ofRhBsolution on the photocatalytic degradation percentage (PDP) of RhB by ZnO nanoparticles.

碩士
高苑科技大學
化工與生化工程研究所
104
In this study, the aquaponic system was set up outdoors and adopted sunlight as the light source to save energy. The processed fish feed and mixed natural fish feed (Sesame dregs, soybean dregs, rice bran: 1:1:1) were supplied for the fish (Zhu Wenjin). The ceramic ring and oyster shell provided the bio media for the transfer of ammonia-nitrogen to nitrate-nitrogen which could be assimilated by vegetables. Moreover, the water quality of the aquaponic system，the growth of vegetables (Oilseed Rape，Chinese Cabbage， Garland Chrysanthemum) , and the nitrate of vegetables were investigated. The results showed that bio media and food of fish affected the water quality and the nitrate amount for vegetables. The most fast and steady growth was Edible Rape on the combination of oyster shell medium and mixed natural fish feed. However, the water containsed a lot of turbidity. It was due to the oyster shell and mixed natural fish feed and the post-filter was not efficient. Further, the Edible Rape still could grow fast by the combination of ceramic ring and processed fish feed. However, the Chinese Mustard and Crown Daisy grew slowly and the effluent water was very clear after the combination process of ceramic ring and processed fish feed. On the other hand, the water quality of dissolved oxygen (DO) was 7.48-8.68 mg/L. It indicated that the DO provided the growth of fish effectively. Moreover, the combination of ceramic ring with processed fish feed resulted in low pH of water and no correlation with the growth of fish. On the other hand, the amounts of nitrate of all the harvested vegetables were lower than the EU nitrate regulation No. 563/2002 summer criteria of 2500ppm. The combination of oyster shell and mixed natural fish feed contained lower nitrate for vegetables.

碩士
國立臺灣科技大學
電子工程系
101
Applying solar energy, natural light illumination system (NLIS) is a low pollution and low energy consumption system. We divide the light transmission process into solar collecting, light transmitting and light emitting for indoor illumination. However, the efficiency of previous static solar collector is about 6%. The energy is difficult to meet the increased demand. In the first section, we review the basic concept of non-imaging optics and how we use the material Polymethylmethacrylate (PMMA) and geometry to design the input area and output optical properties. Subsequently, we verify the beam conversion, luminous flux and luminous intensity by optical simulation software, FRED. We also identify the relation between efficiency and thickness. The energy conversion efficiency under the same area-conditions is 2.61 times. The luminous intensity is distributed in the plus or minus 20 degrees. The light collecting devices can be improved and applied to indoor lighting.

Due to recent economic and infrastructure development in the developing countries like India, China etc., the dependence on artificial sources of energy has increased drastically. Thus Light transmitting concrete is need of the hour. Light transmitting concrete allows natural sunlight or any light to pass through it. It reduces electricity consumption in the buildings and makes it easier for buildings to achieve higher LEED (Leadership in Energy and Environmental Design) rating. It has all the properties what a eco-friendly technique should have to keep up the green building concept into consideration as it increases the use of natural resource i.e. sunlight which is natural light and it reduces the use of electricity, thus, saving power consumption. Light transmitting concrete also gives aesthetically beautiful surface. It is made up of cement, sand, fine aggregates and thousands of plastic optical fiber strands placed in alternate layers. But, no construction material is can be used until it satisfies all the constructional requirements. For this purpose, experimental study on light transmitting concrete has been carried out to determine it’s the light transmittance characteristics with the help of Photometer, device which is used to find the intensity of light in terms of lumens. The Compressive strength of light transmitting Concrete is also found out by testing its cubes with the help of compression testing machine as per the relevant IS code for testing i.e. IS 516:1959. The yielded results shows that light transmittance ratio up to 5.5% can be achieved by using 4% plastic optical fibers in light transmitting concrete. Experimentally found compressive strength results show that there is very little or almost no loss in strength of light transmitting concrete as compared to the traditional concrete. Light transmitting concrete has a very bright future in civil engineering constructions owing to its unique characteristics of transmitting light. Keeping in mind all the advantages of this concrete it is right to say that “Light transmitting concrete is definitely the present as well as future of Civil engineering” as it also encourages the green building concept by reducing the dependence on artificial light sources during the day time. It is also very tremendous innovation in terms of aesthetics and architectural aspect also it gives very pleasing appearance and it can be used for decorative purposes very effectively.

The fast growing production of carbon based nanomaterials (CNMs) and their potential widespread use in consumer products raise concerns regarding their potential risks to human health and ecosystems. The present study investigated the role of photochemical transformation and natural organic matter (NOM) in the fate, transport, and toxicity of fullerenes and carbon nanotubes (CNTs) in natural aquatic systems, providing fundamental information for risk assessment and management. Photochemical transformation of aqueous fullerene nanoparticles (nC60) and CNTs occurs at significant rates under UVA irradiation at intensity similar to that in sunlight. The transformation processes are mediated by self-generated ROS, resulting in changes of surface structure depending on the initial surface oxidation state of CNMs. UVA irradiation leads to oxygenation of nC60 surface and decarboxylation of carboxylated multi-walled carbon nanotubes (COOH-MWNTs). The environmental transport of CNMs is significantly affected by their surface chemistry, concentration and species of electrolytes, and concentration and properties of co-existing NOM. In electrolyte solutions without NOM, the mobility of CNMs is largely decided by their surface chemistry, primarily the oxygen-containing functional groups. In NaCl solutions, UVA irradiation remarkably enhanced the mobility of nC60; conversely, it reduced nC60 stability in CaCl2 solutions. The mobility of COOH-MWNTs in NaCl solutions correlated well with the abundance of surface carboxyl groups. Humic acid, once adsorbed on the nC60 surface, can significantly enhance its stability through steric hindrance. The extent of stabilization depends on the amount and properties of humic acid adsorbed. Humic acid has limited adsorption on UVA-irradiated nC60. Soil humic acid is more efficient in stabilizing nC60 than aquatic humic acid due to its higher molecular weight. Humic acid immobilized onto the silica surface can potential enhance or hinder nC60 deposition, depending on the complex interplay of attractive and repulsive forces. MWNTs are more toxicity to bacteria, Escherichia coli, than COOH-MWNTs due to their higher bioavailability and oxidative capacity. Surface oxidation induced by •OH reduced the toxicity of MWNT while reactions with •OH have little effect on the COOH-MWNT toxicity. Antioxidants such as glutathione can effectively inhibit the antibacterial activity of MWNTs.