743 resultados para Lighting
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Aerial observations of light pollution can fill an important gap between ground based surveys and nighttime satellite data. Terrestrially bound surveys are labor intensive and are generally limited to a small spatial extent, and while existing satellite data cover the whole world, they are limited to coarse resolution. This paper describes the production of a high resolution (1 m) mosaic image of the city of Berlin, Germany at night. The dataset is spatially analyzed to identify themajor sources of light pollution in the city based on urban land use data. An area-independent 'brightness factor' is introduced that allows direct comparison of the light emission from differently sized land use classes, and the percentage area with values above average brightness is calculated for each class. Using this methodology, lighting associated with streets has been found to be the dominant source of zenith directed light pollution (31.6%), although other land use classes have much higher average brightness. These results are compared with other urban light pollution quantification studies. The minimum resolution required for an analysis of this type is found to be near 10 m. Future applications of high resolution datasets such as this one could include: studies of the efficacy of light pollution mitigation measures, improved light pollution simulations, economic and energy use, the relationship between artificial light and ecological parameters (e.g. circadian rhythm, fitness, mate selection, species distributions, migration barriers and seasonal behavior), or the management of nightscapes. To encourage further scientific inquiry, the mosaic data is freely available at Pangaea.
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This paper presents a solution to part of the problem of making robotic or semi-robotic digging equipment less dependant on human supervision. A method is described for identifying rocks of a certain size that may affect digging efficiency or require special handling. The process involves three main steps. First, by using range and intensity data from a time-of-flight (TOF) camera, a feature descriptor is used to rank points and separate regions surrounding high scoring points. This allows a wide range of rocks to be recognized because features can represent a whole or just part of a rock. Second, these points are filtered to extract only points thought to belong to the large object. Finally, a check is carried out to verify that the resultant point cloud actually represents a rock. Results are presented from field testing on piles of fragmented rock. Note to Practitioners—This paper presents an algorithm to identify large boulders in a pile of broken rock as a step towards an autonomous mining dig planner. In mining, piles of broken rock can contain large fragments that may need to be specially handled. To assess rock piles for excavation, we make use of a TOF camera that does not rely on external lighting to generate a point cloud of the rock pile. We then segment large boulders from its surface by using a novel feature descriptor and distinguish between real and false boulder candidates. Preliminary field experiments show promising results with the algorithm performing nearly as well as human test subjects.
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Because of high efficacy, long lifespan, and environment-friendly operation, LED lighting devices become more and more popular in every part of our life, such as ornament/interior lighting, outdoor lightings and flood lighting. The LED driver is the most critical part of the LED lighting fixture. It heavily affects the purchasing cost, operation cost as well as the light quality. Design a high efficiency, low component cost and flicker-free LED driver is the goal. The conventional single-stage LED driver can achieve low cost and high efficiency. However, it inevitably produces significant twice-line-frequency lighting flicker, which adversely affects our health. The conventional two-stage LED driver can achieve flicker-free LED driving at the expenses of significantly adding component cost, design complexity and low the efficiency. The basic ripple cancellation LED driving method has been proposed in chapter three. It achieves a high efficiency and a low component cost as the single-stage LED driver while also obtaining flicker-free LED driving performance. The basic ripple cancellation LED driver is the foundation of the entire thesis. As the research evolving, another two ripple cancellation LED drivers has been developed to improve different aspects of the basic ripple cancellation LED driver design. The primary side controlled ripple cancellation LED driver has been proposed in chapter four to further reduce cost on the control circuit. It eliminates secondary side compensation circuit and an opto-coupler in design while at the same time maintaining flicker-free LED driving. A potential integrated primary side controller can be designed based on the proposed LED driving method. The energy channeling ripple cancellation LED driver has been proposed in chapter five to further reduce cost on the power stage circuit. In previous two ripple cancellation LED drivers, an additional DC-DC converter is needed to achieve ripple cancellation. A power transistor has been used in the energy channeling ripple cancellation LED driving design to successfully replace a separate DC-DC converter and therefore achieved lower cost. The detailed analysis supports the theory of the proposed ripple cancellation LED drivers. Simulation and experiment have also been included to verify the proposed ripple cancellation LED drivers.
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Este artículo tiene como objetivo fundamental mostrar cómo el Instituto de Investigaciones y Experiencias Cinematográficas (IIEC) fue, desde finales de los años cuarenta hasta mediados de los años sesenta, el creador de una escuela de maestros de la luz y cómo la enseñanza de estos nuevos métodos de iluminación traspasó las fronteras de las aulas y marcó el inicio del Nuevo Cine Español. Para ello se han revisado las principales fuentes bibliográficas de los que consideramos fueron los primeros maestros de fotografía que dio el IIEC: Juan Julio Baena, Luis Enrique Torán y Luis Cuadrado, y se ha realizado un análisis fílmico de la primera obra audiovisual de cada uno en la que se instaura un ambiente de renovación, un cambio estético y el uso de unas técnicas fotográficas más realistas. Así mismo, hemos observado cómo la nueva docencia de la fotografía fue trasladada a otras personas que también llegaron a ser maestros y no estudiaron en el IIEC. Por tanto, se trata de una escuela generadora de maestros tanto dentro como fuera de sus aulas.
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PEDRINI, Aldomar; SZOKOLAY, Steven. Recomendações para o desenvolvimento de uma ferramenta de suporte às primeiras decisões projetuais visando ao desempenho energético de edificações de escritório em clima quente. Ambiente Construído, Porto Alegre, v. 5, n. 1, p.39-54, jan./mar. 2005. Trimestral. Disponível em:
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This present study analyses the relationship between national culture and entrepreneurship, in order to contribute in understanding the impact and the influence of Brazilian culture under the business practices of foreign entrepreneur on the tourism area of Rio Grande do Norte state. Researchers in entrepreneurship field, such as Schumpeter (2005), Weber (2006), McClelland (1972), Murphy, Liao, Welsch (2006), Peyrefitte (1999), Blanchflower (1988), Filion (2000), among others, and in the national culture, high-lighting Caldas and Woods (1999), Hofstede (1997) and Barros and Prates (1996), are put together to create a starting point to this present research, that reaches out for a differential approach, in order to create a correlation between Brazilian culture and the foreign entrepreneur, who chose Rio Grande do Norte state to live and invest. It was observed that in the case of the Switzerland entrepreneur, where the cultural difference is more strong, either in Hofstede's perspective than in Brazilian s authors, the management practices are more negatively affected. The rationalization adopted by the entrepreneur and the employee s logic are in battle in a day-to-day operation of the company. In the case of the Argentinean entrepreneur, the cultural difference exists, but it does not impact as much, because of her personal characteristics and the similarities of Latin culture than surfaces the differences. Finally, this study showed the necessity of analyzing the enterprising regarding the cultural issue, in a way to highlight the different rationalities in different atmospheres where it is practiced the enterprise
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Lanthanide doped zirconia based materials are promising phosphors for lighting applications. Transparent yttria stabilized zirconia fibres, in situ doped with Pr3+ ions, were grown by the laser floating zone method. The single crystalline doped fibres were found to be homogeneous in composition and provide an intense red luminescence at room temperature. The stability of this luminescence due to transitions between the 1D2 → 3H4 multiplets of the Pr3+ ions (intra-4f2 configuration) was studied by photo- and iono-luminescence. The evolution of the red integrated photoluminescence intensity with temperature indicates that the overall luminescence decreases to ca. 40% of the initial intensity at 14 K when heated to room temperature (RT). RT analysis of the iono-luminescence dependence on irradiation fluence reveals a decrease of the intensity (to slightly more than ∼60% of the initial intensity after 25 min of proton irradiation exposure). Nevertheless the luminescence intensity saturates at non-zero values for higher irradiation fluences revealing good potential for the use of this material in radiation environments.
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Thesis (Ph.D.)--University of Washington, 2016-08
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This thesis deals with terracotta lamps found at the archaeological site of Agia Paraskevi of Arachamitai during the years 2010–2014. The research questions are: What kind of lamps were used on the site and when? For what purposes were the lamps used? Where were they manufactured? In order to address these questions, a total of fifty lamps have been chosen to form the body of research material. To answer the first research question, a typology for these lamps has been created with twenty-one types and one variant, after examining various lamp typologies and previous publications. The find contexts and distribution of the lamps are both examined to test the dates for the different lamp types gathered from other publications, and to answer the question on what purposes the lamps were used on the site. Visual observation of the clay of the lamps and information on clay materials from other sites are both examined to determine the lamps' origins. The lamps in this study date from the 5th century BC to the 2nd century AD. The find contexts allow the dating of the lamps according to the other publications, but suggestions of more site-specific dates are given to some lamps. The distribution of the lamps indicates that while most were used for everyday lighting at the sanctuary, some may have had ritual connections. Most of the lamps were manufactured locally or at a nearby Arcadian site. Few lamps can be regarded as imports.
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Vivemos um momento de crise, com profundas mudanças globais, a nível político, económico-social e tecnológico, que afetam todos os setores de atividade de forma transversal. A iluminação não está de forma alguma imune a estas alterações. A sobrevivência das empresas requer uma atenção permanente às mudanças do mercado. As formas tradicionais de olhar os mercados e os consumidores, podem tornar-se insuficientes face à rapidez com que as mudanças ocorrem. Algumas metodologias heterodoxas de abordagem ao mercado, como é o caso do coolhunting, começam a ser olhadas de outra forma. Uma das limitações apresentadas na literatura relativamente ao coolhunting é o peso da intuição ou de outras metodologias subjetivas nos resultados obtidos. Numa altura de escassez de recursos, poderá ser problemático para um empresário apostar recursos sem poder contar com números na tomada de decisão, mas apenas em imagens e conceitos. Partindo dos resultados qualitativos de um relatório de coolhunting, este Projeto de Mestrado propõe-se criar e testar uma metodologia que seja capaz de fazer uma análise quantitativa desses resultados de forma que seja possível responder à questão: num determinado mercado que conceitos-chave poderão ter um maior potencial de difusão? Um conjunto de países, de entre os chamados BRIC e os PALOP, foram escolhidos para testar a metodologia. Foi assim possível obter valores em forma de índice comparativo desse potencial de difusão. A metodologia utilizada tem ainda um grande potencial de aperfeiçoamento. Na parte final é apresentada um conjunto de pistas com este objetivo.
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The concepts of light shelves consist of windows that have face towards the sun, which receive a vast quantity of energy that could be used for healthy day lighting. This paper debates a main assessment, investigates the optimization of daylight requirement by means of light shelves system. An experimental test was carried out assessing the measurements and lighting simulations of a model of a building in order to elucidate the characteristics of indoor lighting. Light shelf is an architectural element that permits daylight to enter deep into a building. It constitutes an optimal solution for an incorrect building orientation and less sunny days. The essential objective of this study is to highlight the vital role of light shelves in residential buildings in northern Europa where the requirement is to improve the daylight in the interior functional spaces. The main objects of this paper are to investigate the effect of daylight in the interior functional spaces using light shelves, the effect of natural light diffusion in interior space in the period of low daylight season, and glare effect in this field. This paper investigates a procedure for analysing the daylight performance using software habitat function
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We compare the optical properties and device performance of unpackaged InGaN/GaN multiple-quantum-well light-emitting diodes (LEDs) emitting at ∼430 nm grown simultaneously on a high-cost small-size bulk semipolar (11 2 - 2) GaN substrate (Bulk-GaN) and a low-cost large-size (11 2 - 2) GaN template created on patterned (10 1 - 2) r-plane sapphire substrate (PSS-GaN). The Bulk-GaN substrate has the threading dislocation density (TDD) of ∼ and basal-plane stacking fault (BSF) density of 0 cm-1, while the PSS-GaN substrate has the TDD of ∼2 × 108cm-2 and BSF density of ∼1 × 103cm-1. Despite an enhanced light extraction efficiency, the LED grown on PSS-GaN has two-times lower internal quantum efficiency than the LED grown on Bulk-GaN as determined by photoluminescence measurements. The LED grown on PSS-GaN substrate also has about two-times lower output power compared to the LED grown on Bulk-GaN substrate. This lower output power was attributed to the higher TDD and BSF density.
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Brown dwarfs and giant gas extrasolar planets have cold atmospheres with rich chemical compositions from which mineral cloud particles form. Their properties, like particle sizes and material composition, vary with height, and the mineral cloud particles are charged due to triboelectric processes in such dynamic atmospheres. The dynamics of the atmospheric gas is driven by the irradiating host star and/or by the rotation of the objects that changes during its lifetime. Thermal gas ionisation in these ultra-cool but dense atmospheres allows electrostatic interactions and magnetic coupling of a substantial atmosphere volume. Combined with a strong magnetic field , a chromosphere and aurorae might form as suggested by radio and x-ray observations of brown dwarfs. Non-equilibrium processes like cosmic ray ionisation and discharge processes in clouds will increase the local pool of free electrons in the gas. Cosmic rays and lighting discharges also alter the composition of the local atmospheric gas such that tracer molecules might be identified. Cosmic rays affect the atmosphere through air showers in a certain volume which was modelled with a 3D Monte Carlo radiative transfer code to be able to visualise their spacial extent. Given a certain degree of thermal ionisation of the atmospheric gas, we suggest that electron attachment to charge mineral cloud particles is too inefficient to cause an electrostatic disruption of the cloud particles. Cloud particles will therefore not be destroyed by Coulomb explosion for the local temperature in the collisional dominated brown dwarf and giant gas planet atmospheres. However, the cloud particles are destroyed electrostatically in regions with strong gas ionisation. The potential size of such cloud holes would, however, be too small and might occur too far inside the cloud to mimic the effect of, e.g. magnetic field induced star spots.
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GEA Consulting Engineers, acting as the design engineers, was hired by the owner, East Village 207 Residential LLC2 for energy modeling for compliance with LEED NC V3 -- This report details the results of the energy simulation done with the 100% construction documents -- This report only refers to entities within the LEED3 project boundary -- The project consists of a new eight-story high-end residential condominium building with 81 units, as shown in illustration 1, and approximately 117,905 GSF, equivalent to 10,953.73 m2, is located at 211 E 13th Street in New York, NY -- The residential portion of the building will function 24-7 -- The design goal is to utilize energy efficient measures to reduce electrical energy use and aims to achieve LEED certification -- LEED EA Credit 14 requires a building to demonstrate a percentage improvement in the proposed building performance compared with the baseline building -- The Credit rewards 1 point for achieving 12% reduction in energy costs -- Additionally, the Credit rewards another point for each subsequent reduction of 2% in the building’s energy cost
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The objective of this study is to assess the natural light of the classrooms sectors, at Universidade Federal do Rio Grande do Norte. It was applied the Post-Occupation Evaluation technique, by using questionnaires and brightness levels measurements inside the classrooms. In order to check the users satisfaction degree, it was initially done a general approach on the related aspects to natural light: their characteristics, availability, sources, opening systems and evaluating tools. It was also determined the necessary brightness levels for the activities development in the classroom and the Post-Occupation Evaluation technique used in the search analyses. Then, it was made the UFRN Campus` characterization; the models` definition which formed the data collection basis; the detailing of the procedures used in the research, the processing description and the data analysis. Subsequently, the results that clarify the issues raised were shown through quantitative and / or qualitative data analyses. This research notes a high level of satisfaction by the users, despite some problems such as the reflections occurrence on the board, the lack of uniformity and, occasionally, the brightness low levels