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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Application of nematic liquid crystals as tunable optical filters

Steven, David Paul January 2001 (has links)
No description available.
2

Návrh optického systému LED svítidla / Optical design for LED luminaire

Oravčok, Ján January 2021 (has links)
The first part of the thesis is research, which deals with electric luminaires and especially their light-active parts. Subsequently is described the problem of a specific luminaire, which is used during the control of the surface structure of materials. The next part of the thesis deals with the simulation of the current luminaire and the simulations of the proposed solutions that eliminate the shortcomings of the luminaire. The conclusion of this thesis is the evaluation of the originally used luminaire and the benefits of the proposed solution, which showed the best results in the simulation.
3

A Soft Focus

Limbavali, Revati January 2023 (has links)
The primary objective of this thesis is to create a study lamp based on research into the Zen aesthetic principles and visual perception. Visual perception is impacted by important aspects, especially vertical illumination, it is addressed here in terms of luminaire height. The design makes use of classic materials while adhering to Koko and Kanso's ideas of simplicity and utility. The luminaire's design incorporates soft illumination and flexibility for different desk arrangements in student rooms based on survey data. The design prioritizes glare reduction in form of shielding the light source and offers ambient lighting for screen-contrast, coinciding with research on digital eye strain, considering the widespread vertical illuminance from displays and the related eye strain. User habits relating to time and screen usage provide significant data, defining vertical illuminance concerns and the incorporation of an adjustable sub-body for controlled light distribution. The challenge is to reconcile simplicity with Austere Sublimity while including user demands such as flexibility, glare reduction, and diffused lighting. Natural materials such as wood and paper improve the intrinsic qualities and aging process of the luminaire while also remaining sustainable. The result is a luminaire that successfully combines visual perception, Zen Aesthetic principles, and user requirements.
4

A study of optical properties of various materials as a tool in the process for designing a luminaire

Grahn, Kajsa January 2021 (has links)
Overlooking the important role materials, in relation to light, have in interior design and architecture is not so uncommon. However, materials are not only important for understanding light in architecture, but also in product design since all objects within a space contribute to its visual character and spatial appearance. This study investigates differences in optical properties of a selection of materials often found in Scandinavian domestic environments. It also explores and discusses the main question of how, in the process of designing a luminaire, product and lighting designers could make use of the visual quality differences between the selected materials, and when put in a spatial context how their properties can be used as a tool to create different lighting scenarios. In order to answer the main question, the study applied a practical approach including a small scale and full-scale laboratory, in which the investigation was based on testing and experimenting with light and material and where qualitative and quantitative aspects were observed, measured, and consolidated.
5

Návrh interiérového svítidla / Interior lighting design

Klement, Roman January 2020 (has links)
This diploma thesis deals with the design of a virtual prototype of a luminaire. Using suitable software tools, a luminaire optics is created and optimised. Luminaire is simulated in the interior, and lighting parameters are evaluated. Finally a suitable design is created.
6

LIGHT RECORD PLAYER

Liu, Yanwei January 2022 (has links)
Inspired by the implicit beauty Asian paper could create in interior design (Tanizaki 1977), the cultural and historical value it bears, and its sustainable papermaking process, this research intends to apply Asian paper’s aesthetic and sustainable value in luminaire design. This is an exploratory and project-based study, which includes four steps. The first step investigates different types of Asian paper, their characteristics, and their visual qualities when interacting with light. The second step examines what is available in the market with similar materials in case studies. The third step follows the prototype making with the focus on design for the circular economy. The fourth step concludes the study with an in-depth discussion on sustainability, and in particular, the significance of the application of the circular economy in the lighting industry. The objective is to promote Asian paper as a sustainable material, which is beneficial for creating good light for modern interior lighting design.
7

Développement d'une méthodologie d'essais de fatigue accélérée de pièces mécaniques sur table vibrante

Marin, Frederic 22 February 2010 (has links)
Dans leurs conditions réelles de fonctionnement, les pièces mécaniques, exposées à un environnement vibratoire de longue durée, sont sujettes à un endommagement par fatigue dynamique pouvant conduire à une perte de performance, voire d'intégrité de la structure. Les tests de fatigue accélérée ont pour but de soumettre une pièce mécanique à un essai de vibration, de durée réduite, en laboratoire, tel que le dommage subi soit équivalent au dommage rencontré par la pièce en service. D'une manière générale, les secteurs d'application potentiellement concernés par les tests de fatigue accélérée relèvent de l'industrie mécanique au sens large (industries automobile,aéronautique, spatiale, ferroviaire, ...). La société R-Tech, bureau d'études du groupe Schréder, fabricant d'appareils d'éclairage public, est à l'origine du projet de recherche ayant conduit à la réalisation de ce travail. Celui-ci s'inscrit dans le cadre d'une convention de First-Doctorat Entreprise, cofinancée par la Région wallonne et le partenaire industriel. L'intérêt porté par R-Tech aux résultats de la recherche est lié au fait que tous les luminaires conçus sont dimensionnés par un calcul statique basé sur la méthode des éléments finis et testés en fatigue sur table vibrante avant d'être commercialisés. Malgré ces précautions, dans quelques cas, des problèmes de bris se produisent sur site. Dans d'autres cas, les calculs par éléments finis conduisent à un surdimensionnement des pièces constitutives du luminaire. Il est donc important pour R-Tech de pouvoir disposer d'outils de conception et de validation de conception permettant de développer et de produire de façon économique des luminaires résistant aux sollicitations auxquelles ils sont normalement exposés. En permettant à R-Tech/Schréder de certifier la conception structurale de leurs produits et d'en garantir la durée de vie dès la phase de développement, cette recherche devrait leur apporter un gain de compétitivité. Par conséquent, la méthodologie développée, bien que générale, a été appliquée en priorité aux cas tests fournis par le partenaire industriel. Lorsque la pièce mécanique devant subir l'essai de vibrations n'est pas connue ou complètement définie, la méthodologie proposée se réfère à une approche analytique basée sur un système de référence à un degré de liberté et conduisant à la définition des critères de sévérité que sont les Spectre de Réponse Extrême (SRE), Spectre de Dommage par Fatigue (SDF) ou Spectre d'Energie Dissipée (SED). Cette approche, indépendante du spécimen à tester et dès lors particulièrement indiquée dans le cas de l'élaboration d'une spécification, ne peut cependant fournir que des résultats qualitatifs. L'estimation précise de la contrainte maximale présente dans la pièce testée ainsi que celle de l'endommagement qu'elle génère au cours du temps n'est envisageable, au moyen d'une telle approche, que pour de rares applications relativement simples permettant d'établir la relation qui existe entre contrainte et déplacement relatif. Dans un cas contraire, le recours à un modèle éléments finis du spécimen est nécessaire. Dans le cas particulier des appareils d'éclairage public, l'environnement vibratoire auquel ils sont soumis est essentiellement dû aux sollicitations éoliennes. Des données météorologiques recueillies par l'IRM à Uccle ont permis d'alimenter un modèle de vent qui rend compte des sollicitations aléatoires liées à la turbulence du vent ainsi qu'à un éventuel largage de tourbillons de Von Karman. Ces excitations sont ensuite appliquées à un modèle éléments finis simplifié du système poteau/luminaire. D'autres environnements vibratoires auxquels les luminaires peuvent être soumis au cours de leur vie, tels les sollicitations sismiques induites à la base d'un poteau installé sur pont ou viaduc et l'impact qui lui est appliqué lors de la collision avec un véhicule manoeuvrant sur un parking, ont également été envisagés dans ce travail. Une fois l'environnement vibratoire réel de la pièce mécanique à tester déterminé, soit expérimentalement, soit analytiquement, la méthodologie proposée conduit à l'obtention d'une spécification équivalente au moyen d'un processus d'optimisation développé au sein du logiciel BOSS Quattro (Samtech). Ce dernier minimise la fonction objectif représentant l'écart entre le critère de sévérité retenu pour caractériser les environnements de référence et équivalent. Le test aléatoire équivalent au vent ainsi que le test d'impact sur poteau font désormais partie intégrante de la procédure de qualification des luminaires R-Tech/Schréder. Lorsque la géométrie de la pièce mécanique à tester et la spécification d'essai à reproduire en laboratoire sur table vibrante sont fixées, une modélisation éléments finis du spécimen permet, si pas d'annuler complètement le risque de bris qui pourrait survenir lors de la phase de qualification expérimentale, de le réduire très fortement. Dans l'exemple d'un luminaire, la structure étant rendue complexe par le nombre de pièces qui la constituent et les assemblages qui existent entre elles, une confrontation des résultats de simulation et expérimentaux est nécessaire : analyses modales au marteau d'impact et sur table vibrante en ajoutant un composant à la fois afin de recaler le modèle, comparaison des niveaux d'accélération simulés et mesurés lors de l'essai en vue du recalage des coefficients d'amortissements modaux, validation du modèle sur base des contraintes mesurées au moyen de jauges et/ou rosettes. Une fois les zones jugées critiques repérées, le modèle peut dès lors être utilisé pour prédire la durée de vie du spécimen soumis à son environnement vibratoire. Celle-ci est finalement obtenue en faisant appel aux concepts de contrainte équivalente de Von Mises, approximation bilinéaire de la courbe de Wöhler, contrainte plastique de Neuber et évolution linéaire ou non-linéaire de l'endommagement.
8

The Impacts of Real-time Knowledge Based Personal Lighting Control on Energy Consumption, User Satisfaction and Task Performance in Offices

Gu, Yun 01 May 2011 (has links)
Current building design and engineering practices emphasizing on energy conservation can be improved further by developing methods focusing on building occupants’ needs and interests in conservation. Specifically, the resulting energy effective building performance improvements cannot reach the desired goals, if the resulting indoor environmental conditions do not meet thermal, visual and air quality needs of the occupants. To meet both energy conservation and human performance requirements simultaneously requires to give the occupants information regarding indoor environmental qualities and energy implications of possible individual decisions. This requires that building control components and systems must enable occupants to understand how the building operates and how their own actions meet both their needs and the energy and environmental goals of the building project. The goal of the research and experiments of this dissertation is to explore if real-time information regarding visual comfort requirements to meet a variety of tasks and to simultaneously conserve energy, improves occupant behavior to meet both objectives. Two workplaces in Robert L. Preger Intelligent Workplace were equipped to test the performance of 60 invited participants in conducting computer based tasks and a paper based task, under three difference lighting controls: 1) Centralized lighting control with no user choice 2) User control of - blind positions for daylight shading - ceiling based lighting fixture luminance output level - task lighting: on/off 3) User control the three components (as listed under point 2 above), with provided simultaneous information regarding energy and related CO2 emissions implications, appropriate light levels meeting tasks requirements, and best choices in order to meet both task requirements and energy conservation goals/objectives. The main findings of the experiments are that real-time information (listed under point 3 above) enables users to meet the visual quality requirements for both computer tasks and the paper task, and to conserve significant amounts of electricity for lighting. Furthermore, the 60 invited participants were asked to identify the importance of the four types of provided information tested in point 3 above. While individual users identified the importance of different information categories, the overall assessment were considered to be significant.
9

PATCHES OF LIGHT, A LUMINAIRE WITH USER ADJUSTABLE LIGHT DISTRIBUTION

Mojtahedi, Mahsa January 2021 (has links)
This Master’s thesis is to delineate a luminaire design which has a flexible functional form, can be controlled by the user, and which creates multidirectional light distribution within an indoor space.  A lighting solution with varied light distributions can change a space’s different spatial experiences, granting a flexibility which is controlled by the user to direct light rays into walls, floors, ceilings or to create variations of these. A flexible luminaire in terms of light distribution allows, vertical and horizontal surfaces to be valued equally, because through a minimal intervention it is possible to shift the focus from one surface to another, providing a holistic interplay in space. The participants, who took part in the evaluation program of the final luminaire, freely introduced their possible activities in the predefined dining room, with different lighting proposals according to personal preferences of spatial experience. The designed luminaire was the only accessible tool to influence the space, and they managed to achieve their ideal atmospheres, and experiences, by the process of adjusting the luminaire with controlled light distribution. The varied results of the patterns of brightness and darkness on the vertical and horizontal surfaces in the predefined real space, prove the flexibility of the final design of the luminaire, MM Lamp. The luminaire fulfills the predefined design objectives of being user adjustable as well as creating varied light distribution.
10

A HUG OF LIGHT

Hölbling, Markus January 2021 (has links)
This project is an elaboration of how luminaire design can provide for fundamental human needs. Visual needs in terms of task performance, orientability and visual comfort; emotional needs in terms of soothing feelings of safeness and cosiness; and biological needs in terms of circadian rhythm and resetting of our biological clock in the morning. These needs are tested through three bedroom scenarios named focus, contemplation and dawn, each with their own demands and desires on lighting qualities.  I have submerged into desired lighting qualities and atmosphere in a bedroom context; into how circadian rhythm can be promoted through lighting design; into how the perception of space can be effected through light; into how responsible use of natural resources can be achieved; and finally into what the impact and consequences of the design intervention are. The investigation is performed in a generic bedroom situation without daylight considerations. A prototype has been produced in order to perform observations and measurements.  Through the investigation I can state that luminaire design is able to provide for visual, emotional and biological needs. By simultaneously working with light qualities and shape of the luminaire, and having formulated the specific scenarios focus, contemplation and dawn, qualitative observations and experience could be supplemented by quantitative measurements and drive the design process forward towards intended lighting effects, characteristics and impacts on the human body and mind.

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