A comparative study of high intensity DC and AC vortex stabilized arcs operating in argon (at pressures of one to five atmospheres) has been conducted. The energy balance for both the AC and DC arcs has been determined calorimetrically. From these measurements the radiative efficiency (radiation losses/input power) has been calculated. It was found over the current range examined (150-450 amperes) that the radiative efficiency of the AC vortex stabilized arc was comparable to the DC arc. Since DC vortex stabilized arcs have been used as a high intensity radiation source, these results indicate that the AC vortex stabilized arc shows promise for use as a high intensity radiation source. From the energy balance results the heat transfer to the wall was surprisingly found to scale linearly with the radiation losses. The wall loading is not due to absorption of radiation and is much larger than that expected from laminar radial heat transfer. To investigate this further a simple channel model was developed for the luminous DC arc core. From this model the radius and temperature of the luminous arc core was determined as a function of current. The predicted radii were in good agreement with time integrated photographs of the luminous core of the arc. At high current (I>350 amperes) the DC arc radius was essentially constant. The wall heat transfer continued to increase when the arc radius was essentially constant, so that highly efficient heat transfer processes must be taking place outside the central luminous arc core. It is believed that turbulent mixing might be present in this region and be responsible for the large wall heat transfer. The heat transfer processes to the arc electrodes have been measured calorimetrically and the electrode surface temperature has been measured spectroscopically. For both AC and DC electrodes the heat transfer scaled linearly with the arc current. The electrode voltage drop is strongly dependent on gas flow direction with the voltage drop always larger for flow towards the electrode than for flow away from the electrode. These results are not due to convective heat transfer effects. The geometry of the electrode arc attachment region changes when the flow direction is reversed. It is believed that both the anode and cathode fall potentials are altered when the flow direction is reversed, and this is responsible for the difference in electrode voltage drop when the flow direction is reversed. From the electrode surface temperature measurements the heat transfer to the arc electrodes was shown to be essentially one-dimensional in nature. A model of the AC electrode heat transfer was developed using the DC heat transfer results which predicts results for the electrode voltage drop that are in good agreement with the experimental results. The AC electrode heat transfer was found to be <50% of the anode heat transfer in a DC arc at the same current. In the DC arc the anode heat transfer is much larger than the cathode heat transfer. For a practical DC vortex stabilized arc radiation source anode failure is a serious problem, so that the results for the AC electrode heat transfer is of considerable practical importance. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

The diploma thesis includes design of smart child lighting that takes into account the effects of colour spectrum changes on the human sleep regime.

In the final thesis I dealt with morphology of interior lighting. I chose a collection of table lamps, floor lamps and pendant chandelier. Based on the study of the historical development of lights that I applied in my theoretical thesis, I have designed the lighting for contemporary interior with the use of new light sources.

The subject of this thesis is to look back at my entire time in the Theater Department at Temple University, to reflect and see how my design process has changed and grown during my time in graduate school. I also look at three of my lighting designs and reflect what I learned, what I would change, and challenges I faced along the way. In addition, I look at four of my classes I have taken that I would call essential to my degree and reflect on them as well. I reflect on my semester of teaching at the undergraduate level. Finally, I take a look at how COVID has changed our world and the world of theatre, and what I have learned from it, and how I have grown. / Theater

The concept of visiting a restaurant is no longer related to the consumption of a food. The total process of visiting a restaurant became a pleasant experience to elevate mood and satisfaction and create a memorable experience. In this thesis, we aim to case study three restaurants of the same brand using quantitative and qualitative measurements such as questionnaire, V/P theory, and measurements. Moreover, the results of the assessments will be used to investigate how lighting can improve the dining experience in the restaurant while taking into consideration reducing energy consumption. The results of the quantitative and qualitative analysis indicated the lighting in each of these restaurants differs from each other, and they require a redesign to enhance customer satisfaction and to be more energy efficient. The thesis presented a lighting solution which considers all the relevant factors for customer satisfaction from literature and standards. The solution can improve the customer experience in the restaurant and advance its compliance with the sustainability goals.

Lighting is one of the most important issues for the perception of the physical environment and the ability to perform. Lighting design of classrooms is therefore crucial to achieve the goals of education. The Swedish school aim to provide a working environment supporting every child. As children are individuals their perceptions and light preferences differ just as adults do. Accessibility to tools to be able to customize for the individual child are therefore important. To support our planet, every new product developed should be considered regarding sustainability.  This is particularly important of products designed for children as they are our future. This thesis will focus on finding a task light option suitable for the classroom environment. By researching literature, performing market research and conducting interviews with school professionals, important characteristics of a school task light were established. Based on the findings, a task light proposal was developed including the defined properties.

No description available.

A system capable of adjusting a computer vision system to unpredictable ambient lighting has been designed and attached to a silhouette robot vision system. Its principle of operation is based on the generation and analysis of the distribution of light in one T.V. frame. Designed to be used in robot vision applications, high speed processing of data is achieved in the system to generate a histogram of grey levels in one frame time. An addressable RAM technique for this purpose is explained. The system obtains two threshold values from the histogram of grey levels and places them into a threshold logic unit. A silhouette from a grey level picture is obtained as the result of the process. Adaptability of the system is performed by using different integration times in the read out of the visual transducer. The implementation of the system is based on a video rate histogram generator, a sensitivity control unit, a DMA circuit, an 86/12A microcomputer and a solid state T.V. camera. A graphics printer is used to print out results and a CRT terminal to communicate with the microcomputer. The custom hardware and software implementations for the system are depicted in detail. / Thesis / Master of Engineering (ME)

The purpose of this study is to make a report on the lighting experiment as it was carried on in the John N. Reagan School and to present the findings of a number of tests that were given the children in this school and in another comparative school in the same system where no lighting modifications were made.

The thesis is focused on the problems of illumination of interior space, especially in object in Moravský Písek. The thesis is divided into two parts, where the first part deals in general with the basic quantities and terms which are used in illumination systems. Further, it is about general properties of lights and about general terms of illumination of interiors. The second part is only practical character. At the beginning, there is used manual measurement and modelling to evaluate initial state in program Relux. The measurement is not met in terms of standards. Thanks to the municipal council of Moravský Písek a new lighting system is created, which fully respects the valid normative regulations. Installation of control system of lighting is integrated to proposal, which would result in lower consumption, greater user comfort and greater versatility in the possible use of the object. In the end, there is financial evaluation of illuminating system and comparison classical with led technology.