No description available.

The popularity of the atria after its revival since the 1970's has caught the attention of designers and opened ways for new strategies of energy conservation for large buildings. Early atria were visual statements rather than integrated energy systems. But a growing recognition of the contribution of daylight for energy conservation in atria requires study in greater depth to exploit the potential of the atrium in the use of daylight for energy conservation. Present methods for calculating daylight distribution in conventionally designed buildings are not presently configured to deal with atria. This study takes advantage of scale model simulation process to develop a mathematical model which will predict daylight distribution in a square atrium under an overcast sky. Data generated from twelve model studies representing thirty six cases were analyzed using statistical methods as a measure to develop the mathematical model. The mathematical model developed has the ability to predict illumination level on the vertical surface at different floor locations in a square type atrium within the specified limitations. This model is reliable, as the predicted illumination levels have been found to have strong correlation with the values obtained from scale model studies. The mathematical model can be effectively used to assist designers in estimating illumination levels in an atrium and to provide opportunity to test design alternatives while the design is in the preliminary design stage. / Master of Science

This study compared two LED luminaires and their abilities to provide detection distance and color recognition distance of potential roadway hazard. Detection distance is regarded as a metric of visibility. Color recognition distance is a metric for comparing the impact of the (Correlated Color Temperature) CCT of each luminaire and their color contrast impact. Mesopic vision, the mode of vision most commonly used for night driving, was considered in this study. Off-axis objects were presented to participants to assess the peripheral abilities of the luminaires. The impacts of luminance and color contrast were addressed in this study. The experiment was performed on the Virginia Smart Road where standard objects of different colors and pedestrians wearing different colors were detected by drivers of a moving vehicle in a controlled environment. The key difference between the two luminaires was their color temperatures (3500K versus 6000K). The results indicated that neither light source provided a significant benefit over the other although significant interactions were found among object color, age, and lighting level. The results indicate that the luminaires provide similar luminance contrast but their color contrasts depend heavily on the color temperature, the object, and the observer. This study followed the protocol developed by the Mesopic Optimisation of Visual Efficiency (MOVE) consortium developed by the CIE for modeling mesopic visual behavior. / Master of Science

This thesis seeks to create an architectural response for learning spaces that gathers community. A school and community center are explored through the interaction at public and private zones, and day and night operation. The thesis develops a propositional response to the dualities through material, light, and scale. A particular focus within the study of light is the effort to minimize solar gains while improving daylight and view to the outside that is challenging in hot climates, such as in Jeddah, Saudi Arabia. / Master of Architecture / This thesis seeks to create an architectural response for learning spaces that gathers community. A school and community center are explored through the interaction at public and private zones, and day and night operation. The thesis develops a propositional response to the dualities through material, light, and scale. A particular focus within the study of light is the effort to minimize solar gains while improving daylight and view to the outside that is challenging in hot climates, such as in Jeddah, Saudi Arabia.

There is a growing recognition in design professions that lighting is a significant factor in energy consideration. This has generated an interest in daylighting; the bringing of direct and diffuse daylight into buildings to reduce the use of artificial lighting. Many methods exist for quantifying diffuse daylight distribution for use in the design of buildings, but the methods vary widely both in technique and capability. Moreover, no present method deals with direct daylight (sunshine) distribution. Additionally, none have taken advantage of improvements in computer technology that make feasible more complex mathematical computational models for dealing with direct and diffuse daylight together. This dissertation describes the theoretical development and computer implementation of a new mathematical approach to analyzing the distribution of direct and diffuse daylight. This approach examines light transfer from extraterrestrial space to the inside of a room based on the principles of astrometry, solid geometry, and radiation transfer. This study discusses and analyzes certain aspects critical to develop a mathematical model for evaluating daylight performance and compares the results of the proposed model with 48 scale model studies to determine the validity of using this mathematical model to predict the daylight distribution of a room. Subsequent analysis revealed no significant variation between scale model studies and this computer simulation. Consequently, this mathematical model with the attendant computer program, has demonstrated the ability to predict direct and diffuse daylight distribution. Thus, this approach does indeed have the potential for allowing designers to predict the effect of daylight performance in the schematic design stage. A microcomputer program has been developed to calculate the diffuse daylight distribution. The computation procedures of the program use the proposed mathematical model method. The program was developed with a menu-driven format, where the input data can be easily chosen, stored, and changed to determine the effects of different parameters. Results can be obtained through two formats. One data format provides complete material for analyzing the aperture size and location, glass transmission, reflectance factors, and room orientation. The other provides the graphic displays which represent the illuminance in plan, section, and 3-dimensional contour. The program not only offers a design tool for determining the effects of various daylighting options quickly and accurately in the early design stage, but also presents the daylight distribution with less explanation and with more rapid communication with the clients. The program is written in BASICA language and can be used with the IBM microcomputer system. / Ph. D.

[ES] En este trabajo se presenta un estudio detallado de los procesos de transferencia de calor en luminarias LED de alta potencia (HP-LED) con disipadores de calor pasivos y el análisis de variables energéticas: consumo eléctrico y concentración de CO2, para obtener correlaciones que predigan el rendimiento energético de edificios. Como primer objetivo, se diseñan disipadores de calor adecuados a luminarias de distintas potencias. Para ello, se parte de un modelo matemático completo que describe la transferencia de calor en este tipo de sistemas, se realiza la simulación numérica usando métodos de elementos finitos y, además, se comprueban los resultados obtenidos en el laboratorio. Hemos centrado nuestro análisis en el caso de una fuente LED en contacto térmico con un disipador de calor pasivo de aluminio, obteniendo un excelente ajuste entre las mediciones experimentales y las simulaciones numéricas realizadas. Con estos disipadores se garantiza tanto el comportamiento óptimo como la durabilidad de las luminarias. Posteriormente como segundo objetivo, se estudia la relación de dos variables clave del rendimiento energético de un edificio: el consumo de energía y la concentración de CO2, cuyas correlaciones no han sido consideradas en la literatura. Para alcanzar este objetivo, se seleccionaron dos instalaciones ubicadas en diferentes continentes y se adquirieron los datos necesarios para su análisis con un sistema simple y económico para medir, transmitir y gestionar la información. La determinación matemática de la relación entre dos variables facilitará en gran medida la programación de algoritmos eficientes de control energético de instalaciones en plataformas de gestión energéticas. El manejo de toda la información obtenida mediante sensores y gestionada a través de plataformas inteligentes requiere el desarrollo de líneas de investigación relacionadas con el Internet de las Cosas (IoT) y que pertenecen a la era de la Industria 4.0. Los estudios incluidos en esta tesis doctoral pertenecen a dos áreas de trabajo que contribuyen a comprender y mejorar el rendimiento de las Smart cities: el uso de la información para convertir nuestros edificios en instalaciones sostenibles y el desarrollo de la iluminación inteligente (Smart lighting), consiste en incorporar sensores a las luminarias para convertir el sistema de iluminación pública de una ciudad en un laboratorio distribuido de variables de interés gestionado a través de plataformas inteligentes. / [CA] En aquest treball es presenta un estudi detallat dels processos de transferència de calor en lluminàries LED d'alta potència (HP-LED) amb dissipadors de calor passius i l'anàlisi de variables energètiques: consum elèctric i concentració de CO2, per a obtindre correlacions que prediguen el rendiment energètic d'edificis. Com a primer objectiu, es dissenyen dissipadors de calor adequats a lluminàries de diferent potències. Per a això, es parteix d'un model matemàtic complet que descriu la transferència de calor en aquest tipus de sistemes, es realitza la simulació numèrica usant mètodes d'elements finits i, a més, es comproven els resultats obtinguts en el laboratori. Hem centrat la nostra anàlisi en el cas d'una font LED en contacte tèrmic amb un dissipador de calor passiva d'alumini, obtenint un excellent ajust entre els mesuraments experimentals i les simulacions numèriques realitzades. Amb aquests dissipadors es garanteix tant el comportament òptim com la durabilitat de les lluminàries. Posteriorment com a segon objectiu, s'estudia la relació de dues variables clau del rendiment energètic d'un edifici: el consum d'energia i la concentració de CO2, les correlacions de la qual no han sigut considerades en la literatura. Per a aconseguir aquest objectiu, es van seleccionar dues installacions situades en diferents continents i es van adquirir les dades necessàries per a la seua anàlisi amb un sistema simple i econòmic per a mesurar, transmetre i gestionar la informació. La determinació matemàtica de la relació entre dues variables facilitarà en gran manera la programació d'algorismes eficients de control energètic d'installacions en plataformes de gestió energètiques. El maneig de tota la informació obtinguda mitjançant sensors i gestionada a través de plataformes intelligents requereix el desenvolupament de línies d'investigació relacionades amb l'Internet de les Coses (IoT) i que pertanyen a l'era de la Indústria 4.0. Els estudis inclosos en esta tesi doctoral pertanyen a dues àrees de treball que contribueïxen a comprendre i millorar el rendiment de les Smart cities: l'ús de la informació per a convertir els nostres edificis en installacions sostenibles i el desenvolupament de la illuminació intelligent (Smart lighting), consistix a incorporar sensors a les lluminàries per a convertir el sistema d'illuminació pública d'una ciutat en un laboratori distribuït de variables d'interés gestionat a través de plataformes intelligents. / [EN] This work presents a detailed study of the heat transfer processes in high power LED luminaires (HP-LED) with passive heatsinks and the analysis of energy variables: power consumption and concentration of CO2, to obtain correlations that predict the energy performance of buildings. As a first objective, heat sinks appropiate for luminaires of different powers are developed. For this, we start from a complete mathematical model that describes the heat transfer in this type of systems, the numerical simulation is performed using finite element methods and, in addition, the results obtained in the laboratory are compared. With these heatsinks, the optimum performance and durability of the luminaires is guaranteed. Later, we propose to study the relation between two key variables of building performance: the power consumption and the CO2 concentration, whose correlations have not been considered in the literature. To achieve this objective, two buildings located in different continents were selected and the necessary data were acquired for their analysis with a simple and economical system to measure, transmit and manage the information. Therefore, the mathematical determination of the relationship between the two variables will greatly facilitate the programming of algorithms in the energy management platforms. The management of all information obtained through sensors and managed through intelligent platforms requires the development of research lines related to the Internet of Things (IoT) and that belong to the era of Industry 4.0. The studies included in this doctoral thesis belong to two areas of work that contribute to understanding and improving the performance of Smart Cities: the use of information to turn our buildings into sustainable installations and the development of smart lighting, consists of incorporating sensors to the luminaires to convert the public lighting system of a city into a distributed laboratory of variables of interest managed through intelligent platforms. / Al Consejo Nacional de Ciencia y Tecnología, CONACYT, y de manera muy especial al Instituto de Innovación y Transferencia de Tecnología del Estado de Nuevo León, i2t2, quienes en conjunto me brindaron el apoyo económico para realizar mis estudios de Doctorado en el Extranjero con el número de Beca 296471 y CVU: 558076. / Hernández Luna, MC. (2019). Modelado matemático para eficiencia energética: aplicaciones a iluminación LED y al monitoreo de edificios [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/131696

No / The luminance and colour gradients across an image are the result of complex interactions between object shape, material and illumination. Using such variations to infer object shape or surface colour is therefore a difficult problem for the visual system. We know that changes to the shape of an object can affect its perceived colour, and that shading gradients confer a sense of shape. Here we investigate if the visual system is able to effectively utilise these gradients as a cue to shape perception, even when additional cues are not available. We tested shape perception of a folded card object that contained illumination gradients in the form of shading and more subtle effects such as inter-reflections. Our results suggest that observers are able to use the gradients to make consistent shape judgements. In order to do this, observers must be given the opportunity to learn suitable assumptions about the lighting and scene. Using a variety of different training conditions, we demonstrate that learning can occur quickly and requires only coarse information. We also establish that learning does not deliver a trivial mapping between gradient and shape; rather learning leads to the acquisition of assumptions about lighting and scene parameters that subsequently allow for gradients to be used as a shape cue. The perceived shape is shown to be consistent for convex and concave versions of the object that exhibit very different shading, and also similar to that delivered by outline, a largely unrelated cue to shape. Overall our results indicate that, although gradients are less reliable than some other cues, the relationship between gradients and shape can be quickly assessed and the gradients therefore used effectively as a visual shape cue.

Sea turtles face numerous threats on their nesting beaches, including habitat degradation, artificial lighting, and human interventions like beach nourishment projects. These factors can disrupt nesting behavior and reduce overall reproductive success. This study examined the impact of anthropogenic disturbances, specifically artificial lighting and beach nourishment projects, on the nesting success (quantified as portion of adult female emergences resulting in a nest) of loggerhead (Caretta caretta) and green turtles (Chelonia mydas) in southern Brevard County, Florida. Utilizing a long-term dataset (1989-2023) from the UCF Marine Turtle Research Group, the research focused on the Archie Carr National Wildlife Refuge (ACNWR), a site with minimal lighting and development, and the Brevard County Mid Reach, an area characterized by high levels of artificial lighting and development. I aimed to: (1) evaluate the effects of artificial lighting on nesting success by comparing 1989-2023 data from ACNWR and Mid Reach; (2) assess the impact of beach nourishment projects by analyzing nesting success before and after nourishment events, which began in 2005; and (3) explore the interaction between artificial lighting and beach nourishment by comparing nesting success in areas with varying levels of lighting and development. The study found that both loggerhead and green turtle nesting success were lower in areas with high-lighting compared to more natural, low-lighting areas, as well as following more frequent, larger-scale nourishment projects. This research provides new insights into how these human activities influence sea turtle nesting behaviors and the effectiveness of conservation measures like the establishment of the ACNWR in mitigating these impacts. Findings can contribute to the development of strategies to enhance sea turtle conservation efforts in regions experiencing similar pressures.

[pt] Neste trabalho é apresentada a implementação e aplicação de uma técnica experimental ótica, já descrita na literatura, para a medição instantânea do campo de velocidades gerado em escoamento bifásico líquido-gás. O trabalho concentrou-se no regime de escoamento em golfadas. Água e ar foram utilizados como fluidos de trabalho nos testes. A técnica implementada combina Velocimetria por Imagem de Partículas (PIV - Particle Image Velocimetry), com Fluorescência Induzida por Laser (LIF - Laser Induced Fluorescence) e Iluminação Pulsada de Fundo (PST - Pulsed Shadow Technique), o que permite determinar simultaneamente o campo instantâneo de velocidade na água gerado pela passagem da bolha de ar, assim como a forma e velocidade da bolha. Processamento digital de imagens foi utilizado para extrair as informações sobre o campo de velocidade do líquido e as características da bolha. A técnica implementada foi aplicada no escoamento gerado pela passagem de uma bolha de gás em uma coluna de líquido estagnado. A técnica PIV foi utilizada para determinar o campo de velocidades na fase líquida iluminando-se o escoamento com um plano de luz laser pulsada. O uso de partículas fluorescentes em conjunto com filtros óticos posicionados em frente a uma câmera digital permitiram suprimir a reflexão intensa proveniente das interfaces líquido-gás e das paredes do tubo. Entretanto, esta técnica não é capaz de determinar a exata posição da interface líquido-gás. O uso da iluminação pulsada de fundo proveniente de um painel de LEDs permite a visualização da interface gáslíquido com boa definição. Uma única câmera digital posicionada ortogonalmente ao plano de luz laser e em oposição ao painel de LEDs foi usada para o registro das imagens. Os resultados obtidos revelaram com excelente resolução os detalhes do escoamento na esteira, filme na parede e nariz de uma bolha ascendente, comprovando a eficácia da técnica implementada. / [en] This work presents the implementation of a non-intrusive optical technique for measuring the hydrodynamic characteristics of liquid- gas, two-phase flows. The work was limited to the study of air-water slug flows. The technique implemented, already described in the literature, combines Particle Image Velocimetry - PIV, Laser Induced Fluorescence - LIF, and pulsed background illumination, known as Pulsed Shadow Technique - PST. The combination of these techniques allows the simultaneous measurement of the instantaneous flow field generated in the liquid by the passage of the air bubble, together with the shape and velocity of the bubble. The technique was employed in the study of an air bubble rising in a stagnant liquid layer. The PIV technique was employed in the determination of the instantaneous flow field in the liquid using fluorescent particles illuminated by a pulsed laser sheet. An optical high-pass filter was used to block the light scattered by the air-water interfaces and by the pipe walls, allowing the digital camera employed to only capture the particle positions. A LED panel furnished back illumination at a wave length that passed through the high-pass filter and allowed an accurate determination of the bubble shape. A digital image processing procedure was employed to determine the bubble shape, velocity and liquid flow field. The results obtained revealed, with excellent resolution, the details of the liquid flow at the wake, wall film and nose of the rising bubble, thereby attesting to the quality of the technique implemented.

Thesis (M. Tech.) -- Central University of Technology, Free State, 2007 / The lack of a standardized lighting instrument to be used in conjunction with existing photographic methods to document rock art, is a problem experienced in archaeological circles. Through interviews with archaeologists and an investigation into existing photographic methods concerning the photographing of rock art, a demand for a portable and modular lighting instrument was confirmed. The aim of this study, then, was to develop a prototype lighting instrument to fill this void. The design and manufacture of the modular lighting instrument entailed the harnessing of the technological advances made in the field of rapid prototyping. A brief overview of the San/Bushmen of Southern Africa is given to stress the importance of this study and to emphasise the importance of the art of the Bushman in our collective art heritage. An overview of the documenting of rock art and therewith an investigation into documented works of rock art and rock engravings by the San/Bushmen serves as a point of departure for the present inquiry. Tests undertaken with the modular lighting instrument, and a comparison of the results so obtained with existing photographic methods, showed that with the use of the modular lighting instrument, an improvement in illumination, rock-face texture and colour contrast in the images was obtained. The modular lighting instrument helps to create and regulate a suitable lighting environment irrespective of natural lighting circumstances and environments. It produces better results when it comes to documenting rock art in comparison to existing methods of documentation. Continued study for the development of the modular lighting instrument is recommended in order to produce more constant results.