Particle characterization is important to the aerospace field because particle ingestion in propulsion engines can lead to catastrophic failures. It has been shown laser based methodologies can determine size and concentration of spherical particles by using light extinction. However, when one moves to increasingly complex shapes one must take into consideration not only light extinction but multi angle light scattering. Cylindrical particles scatter light in a way that can be quantified by electromagnetic wave theory. This scattering distribution is directly related to the cylinders diameter and material properties, as well as the wavelength of the incident light. This project designed and implemented a rig that measures the scattering distribution of single static cylindrical particles. It was shown that the scattering distribution for cylinders can be measured and compared to computational expected values, especially in the forward scattering region. Future work in measuring the scattering distribution of increasingly complex geometries and in flow conditions is proposed. / Master of Engineering

For humans, architecture is a shelter for dwelling. People seek protection and a sense of belonging in their surroundings. Architecture should reveal the time passage, changes in weather and the character of the place in order to make a place for people to dwell. Sunlight, as an abstraction of the sun, can be received by architecture and connect the place with the universe. This thesis explores how to apply sunlight research as a meaningful tool in architecture design. The research focused on two criteria: orientation and identity. Orientation and identity are the two elements that make a location into a place and make a space into a room. / Master of Architecture / This project is a church located by the Blue Lagoon in Iceland. Light and color are used as means to reveal the movement of the sun and express local memory. The thesis focuses on how sunlight can be introduced into a room and the atmosphere that can be created. As a result, the church is able to tell about its surroundings and make people comfortable.

According to the U.S. Department of Energy, the energy consumption for lighting is estimated to be about 22% of the total electricity generated in the U.S for the year 2001. With the very poor conversion of electrical energy to visible radiation there is an immediate need to adopt new and efficient lighting solutions. Virginia Tech with its own commitment to reduce energy consumption is continuously looking and experimenting with the latest and most efficient lighting solutions for the interiors and exteriors of buildings on its campus. This study seeks to evaluate the performance of selected exterior and interior lighting solutions through experimental and simulation means. A proposed exterior lighting solution, for the "Hokie" light, the most common outdoor lamp fixture on campus, was monitored and evaluated under control settings in the Environmental Systems Laboratory at Virginia Tech. Options for improving the performance of the Hokie light and reducing the uplight were experimentally tested and analyzed. Use of a non-perforated aluminum LiteLid® was selected as the most promising and cost effective solution after analyzing the performance of a variety of options. For general interior lighting, the feasibility of using advanced lighting methods such as Light Emitting Diodes (LEDs) was explored and analyzed. The performance of LEDs was experimentally compared with the existing fluorescent lamps. Performances of the fluorescent and LED lamps were analyzed for selected parameters such as the quality, color and quantity of the light. The annual energy consumption and utility cost of a representative building on the Virginia Tech campus with existing fluorescent lamps and the proposed LED lamps was estimated using E-Quest simulation software. The building chosen for this purpose was the newly constructed Institute for Critical Technology and Applied Science (ICTAS). Low lumen output of the LED lamps and burnout due to heat dissipation and poor color rendition index (CRI) of the LED lamps makes them unviable for interior applications at this time. / Master of Science

The problem was to study the behavior of several hydrocarbons when they were subjected to ultraviolet light of 2536 Å in the presence of mercury vapor.

Can a hospital be more than a center for treatment? Can it initiate a sense of healing in the individual as well as the community? The hospital in its early form was a facility meant to house the sick in ancient Egyptian temples. Prayers, sacrifices and dream interpretations were used in the healing process as well as quintessential medical procedures such as opium for pain and stitching of wounds. Monasteries were later established to accommodate travelers, the indigent and the sick. Hospitals were constructed next to Religious institutions but also utilized house calls for the wealthy class. Monasteries were also organized in cloisters which were places of retreats from the mundane. The idea of hospitals today is to diagnose, treat and heal patients which has proven to be effective with most diseases being prevented and eradicated entirely from our day to day lives. However, these conditions aren't as similar in Malawi. The origin of the word hospital is derived from the Latin word "hospitalia" meaning a place of refuge for guests and strangers. The need for effectively functioning hospital in Malawi is apparent, but the need to create a hospital that heals and creates a sense of community and tranquility for both the guest and wondering traveler is paramount. / Master of Architecture / Explorations of the thesis included delving into what it means to live in a communal village to designing a healing hospital from the outside inward to inform the design to it's fruition. Research entailed looking at perspectives of rural living in Malawi and reflecting those elements in the built environment to create a hospital with gardens of healing and roofs that reflect rural architecture and natural materials. Research began with exploring the cultural influences of community and expressing it through graphic representation and data analysis which informed the location of the site in Blantyre, Malawi. The idea of creating a hospital that can heal through gardens of community or "Khonde" that are synonymous with the people of Malawi. The concept of the hospital is based on the organization of a rural village composed of a center point at the driveway entrance which unfurls out to allow for possible future expansion of the campus. The curvature of the maternity breaks the linear organization to help guide the gardens and circulation of pedestrian paths and patients to and from the hospital departments whilst keeping a certain amount of public access and private ownership.

År 1947 förutspådde konstnären Thomas Wilfred att ljuskonst inom 20 år skulle bli en självklarhet inom konstvärlden. Nu, nästan 70 år senare är ljuskonst fortfarande inte en erkänd konstform eller ett definierat begrepp. Idag skapas ljuskonst av konstnärer runt om i världen med tilltagande entusiasm samtidigt som det råder en uppenbar kunskapslucka och förvirring kring ljuskonst vilket denna studie ämnar att stilla. Studien syftar till att belysa värdet och nyttan med ljuskonst som utvecklande faktor för ljusdesignsbranschen. Att konsumera konst är ett sätt att berika den inre repertoaren och inspirationskällan. De frågeställningar som undersökts är ”Vad är ljuskonst?”, ”Vad inom ljuskonst inspirerar ljusdesigners och andra som arbetar med ljus? och ”Vilka innovationer har gått från ljuskonst till ljusdesign?”. Arbetet är fokuserat till personer som arbetar med ljus och studiens definition av ljuskonst är konst som gestaltar eller skapas av ljus. Undersökningen har ett intensivt och kvalitativt upplägg och har genomförst med snöbollsmetoden i form av intervjuer via frågeformulär, som totalt besvarats av nära femtio personer. Kompletterande datainsamlingsmetoder består av massmail, telefonintervjuer och sociala medier. Primärdatan har analyserats genom sammanställning, kategorisering och sammanfattning. Det är mycket stor spridning i hur personer som arbetar med ljus beskriver ljuskonst och vad inom den de inspireras av. Vad som är ljuskonst bestäms av vem som är kreatören, var den är placerad, vad den består av och hur den upplevs. Ljuskonst har ett stort inspirationellt värde för personer som arbetar med ljus, som applicerar influenserna från ljuskonstens in i ljusdesign. Studiens slutsatser består i att ljuskonst kan skapas av både naturligt och artificiellt ljus, kan vara allt från en liten detalj till något stort och iögonfallande, skapas till en unik kontext, har ett budskap, en funktion och skiljer sig från ljusdesign i fråga om syfte och kontext. Det inom ljuskonsten som inspirerar personer som arbetar med ljus är projekt där dagsljus behandlas eller efterliknas, dess teknik och material, ljusfestivaler och andra ljusevent, verk där betraktaren kan påverka och bli en del av ljuskonsten, verk som skapar mönster, objekt med eller av ljus, scenljussättning och friheten som upplevs finnas i skapandet av ljuskonst. Studiens resultat pekar avslutningsvis mot att accentuerad arkitektur, färgat och dynamiskt ljus, ljusprojicerade mönster, neon och att placera armaturer med klassisk design för inomhusbruk i exteriöra miljöer, har gått från att betraktas som ljuskonst till ljusdesign. / In 1947 the artist Thomas Wilfred predicted that light art will become an obvious part of the art world in the next 20 years. Now, almost 70 years later, light art is still not acknowledged or defined - neither as a art form or as an expression. Artists today are creating light art all around the world with increasing enthuiaism but in point of fact there is nothing such as light art, according to the encyclopaedias. There is an obvious gap in knowledge and confusion surrounding the field of light art which this study intends to reduce. The study aims to highlight the value and benefit of light art as developing factor for the lighting design industry. Consuming art is one way of enriching the inner repertoire and inspiration. The examined issues are "What is Light art?", "What within Light art inspire Lighting designers and others who work with light?” and "Which innovations have gone from considered as Light Art to Lighting design?". The work is focused on people who work with light and the definition of light art in this study is: art that portrays or creates from light. The survey has a deep and qualitative approach and is accomplished with the snowball method throughout questionnaires, which all together were answered by nearly fifty persons. Complementary methods of collecting data consist of bulk mail, telephone interviews and the posting of the survey at social media. The primary data has been analyzed through compilation, categorization and summary. People who work with light describes light art, and also what within light art they find inspiring, in many widely different ways. In summary light art is defined by who the creator is, where it is located, what it consists of and how it is perceived. Light art inspire people working with light who apply their influences from the field of light art into the lighting design industry. The conclusions is that light art can be created by both natural and artificial light, from small details to big and eye-catching installations, has an unique context, a message, a function, and differs from lighting design in terms of purpose and context. The specific parts within light art that inspire people working with light are projects where daylight is involved, the technology and materials of the pieces, light festivals and other light events, light art pieces where the viewer can influence and become a part of it, works that create patterns or objects by light, stage lighting and the expressive freedom in the making of light art. The results indicates that accentuated architecture, colored and dynamic light, light patterns, neon and the placing of fixtures with classic design for indoor use in exterior environments, has gone from being considered as light art to lighting design.

This thesis examines the properties of transmission and transport of light and charged particles in periodic or quasiperiodic systems of solid state and optics, especially the nonlinear and external field effects and the dynamic properties of these systems.

Halogen lamps are mostly applied as a light source to the traditional lamp for medical treatment due to its proper color temperature, but it has its disadvantages such as ultraviolet rays and infrared rays which will be harmful to the patients and faculties in the hospitals under long-term exposure. Consequently, using light emitting diode(LED) as a new light source instead of the traditional halogen lamp will be the trend of the future. The purpose of this study is to design a projective LED dental lamp that can achieve the goals of 200mm¡Ñ100mm for light shape and 11000lux illuminance energy by using the optics simulation software, LightTools. Firstly, a single LED lamp module with a high focusing hollow tubular light guide structure was designed and developed comparing with the solid light guide structure used in many commercial projective dental lamp, the hollow tubular light guide structure can decrease illuminance energy lose due to the absorption by tube material. Because the required objective light shape could not be achieved by using the designed light guide structure only, so a lens component was adopted and designed in order to shrink the output light shape to the required size. Finally, through the specific arrangement of position and angle of each LED lamp module, a projective LED dental lamp with 9 LEDs lamp modules which conform with the required illuminance energy was proposed.

Techniques to control dispersion in a medium have attracted much attention due to potential applications to devices such as ring laser gyroscopes, interferometric gravitational wave detectors, data buffers, phased array radars and quantum information processors. Of particular interest is an optical resonator containing a medium with an anomalous dispersion corresponding to fast-light, which behaves as a White Light Cavity (WLC). A WLC can be tailored to improve the sensitivity of sensing devices as well as to realize an optical data buffering system that overcomes the delay-bandwidth product of a conventional cavity. This dissertation describes techniques to tailor the dispersion for fast-light in intracavity media. We present first a demonstration of fast-light in a photorefractive crystal. When placed inside a cavity, such a medium could be used to enhance the bandwidth of a gravitational wave detector. We then describe how a superluminal laser can be realized by adding anomalously dispersive medium inside a ring laser. We identify theoretical conditions under which the sensitivity of the resonance frequency to a change in the cavity length is enhanced by as much as seven orders of magnitude. This paves the way for realizing a fast-light enhanced ring laser gyroscope, for example. This is followed by the development of a novel data buffering system which employs two WLC systems in series. In this system, a data pulse can be delayed an arbitrary amount of time, without significant distortion. The delay time is independent of the data bandwidth, and is limited only by the attenuation experienced by the data pulse as it bounces between two high-reflectivity mirrors. Such a device would represent a significant breakthrough in overcoming the delay-time bandwidth product limitation inherent in conventional data buffers. We then describe our experimental effort to create a fiber-based WLC by using stimulated Brillouin scattering (SBS). Experimental results, in agreement with our theoretical model presented here, show that the WLC effect is small under the conditions supported by current fiber optic technology. We conclude that future efforts to induce a large WLC effect would require fibers with high Brillouin coefficient and low transmission loss, as well as optical elements with very low insertion loss and high power damage thresholds.

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