Thèses : « High light intensity »

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Köhler, Christian. « Ultrashort Light Sources from High Intensity Laser-Matter Interaction ». Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-88076.

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The thesis deals with the development and characterization of new light sources, which are mandatory for applications in atomic and molecular spectroscopy, medical and biological imaging or industrial production. For that purpose, the employment of interactions of high intensity ultra-short laser pulses with gaseous media offers a rich variety of physical effects which can be exploited. The effects are characterized by a nonlinear dependency on the present light fields. Therefore, accurate modeling of the nonlinearities of the gas is crucial. In general, the nonlinearities are due to the electronic response of the gas atoms to the light field and one distinguishes between the response of bound and ionized electrons. The first part investigates laser pulse self compression, where the consideration of a purely bound electron response is sufficient. We apply an exotic setup with an negative Kerr nonlinearity in order to avoid spatial collapse of the beam on the cost of dealing with an highly dispersive nonlinearity. Analytical analysis and numerical simulations prove the possibility of laser pulse compression in such setups and reveals a new compression scheme, where the usually disturbing dispersion of the nonlinaerity is responsible for compression. Dealing with tera-Hertz generation by focusing an ionizing two-color laser pulse into gas, the second part exploits a medium nonlinearity caused by ionized electrons. We reveal in a mixed analytical and numerical analysis the underlying physical mechanism for THz generation: ionized electrons build up a current, which radiates. Thereby, the the two-color nature of the input laser is crucial for the emitted radiation to be in the tera-Hertz range. Combining this physical model with a pulse propagation equation allows us to achieve remarkable agreement with experimental measurements. Finally, the third part deals with nonlinearities from bound as well from ionized electrons on a fundamental level. We advance beyond phenomenological models for responses of bound and ionized electrons and quantum mechanically model the interaction of an ultra-short laser pulse with a gas. Already the simplest case of one dimensional hydrogen reveals basic features. For low intensities, the Kerr nonlinearity excellently describes the response of bound electrons. For increasing intensity, ionization becomes important and the response from ionized electrons is the governing one for high intensities. This quantum mechanical correct modeling allows us to explain saturation and change of sing of the nonlinear refractive index and to deduce suited approximate models for optical nonlinearities.

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Hutchison, Steven J. « An analysis of light infantry effectiveness in mid-to-high intensity conflict deliberate attack missions ». Thesis, Monterey, California. Naval Postgraduate School, 1991. http://hdl.handle.net/10945/27967.

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This thesis documents a simulation study of light infantry operations in mid-to-high intensity conflict. An initial data analysis is performed using deliberate attack missions conducted at tile U.S. Army National Training Center (NTC) and compares the measures of effectiveness (MOE) of fully modernized heavy forces to the effectiveness of heavy forces operating with an attached light infantry battalion. This analysis includes development of a light infantry attack simulation which employed object oriented programming in MODSIM II. The simulation models light infantry operations in the NTC environment and is used to explore alternative tactical employment techniques designed to enhance unit performance on the AirLand Battlefield. This thesis also describes the tank and mechanized infantry task force. The light infantry task force, the heavy/light rotation concept, the deliberate attack mission, and the NTC environment and data collection capabilities. The simulation models an infantry attack against opposing forces in fixed, fortified positions. The model is a high resolution simulation which builds object code from infantry platoon level through battalion. The simulation depicts unit movements, attrition to indirect fires, and target engagements. The positioning of enemy forces is extracted from actual battlefield positions during an NTC deliberate attack mission. The simulation replicates close operations in which the light force mission is to gain an initial penetration of enemy barriers and pass the heavy force forward to continue the attack. The simulation study explores the use of light forces in alternative tactical scenarios. National Training Center heavy/light rotation, Simulation

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Murdoch, Lynne Elizabeth. « An investigation into the use of High-Intensity Narrow Spectrum light as a decontamination technology ». Thesis, University of Strathclyde, 2010. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=22623.

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Control of contaminant microorganisms is important in many different settings, particularly in healthcare and food production and processing, where environmental contamination by pathogenic microorganisms can be detrimental to human health. In the UK, the number of hospital-associated infections (HAI) and food-related illnesses continues to rise. As such, alternative and complementary disinfection and decontamination technologies are constantly being sought. This investigation examined the inactivation efficacy of High-Intensity Narrow Spectrum Light (HINS-light) on a wide range of microorganisms using LED arrays that emitted intense 405-nm light. The theorised inactivation mechanism involves 405-nm stimulation of endogenous porphyrins, ultimately leading to production of reactive oxygen species (ROS) that cause oxidative cell damage and microbial inactivation. All tested microorganisms associated with HAI and foodborne illnesses were readily inactivated by 405-nm light. It was als o established, for the first time, that 405-nm light was germicidal to eukaryotic microorganisms, including Candida albicans, Saccharomyces cerevisiae and the spore-forming fungus Aspergillus niger. Further examination found 405-nm light induced toxic photo-product formation in Nutrient Broth. The photo-product was particularly toxic to Staphylococcus aureus, methicillin-resistant S. aureus (MRSA) and Acinetobacter baumannii, although it elicited either no effect or a bacterio-static effect in other tested bacteria. HINS-light is known to be less germicidal than pulsed ultraviolet (PUV) light produced from a Xenon flashlamp, however this study has demonstrated that sublethally PUV-damaged S. aureus cells can undergo photoreactivation upon exposure to 300-500-nm light, with maximum effect elicited at 360-380 nm. This photoreactivation potential, that can affect the inactivation capability of UV-light decontamination technologies, was not found to be associated with HINS-light treatment. In addition, HINS-light technology has significant safety advantages over UV light thereby permitting its use in occupied environments. This study has greatly extended the range of microorganisms that have been shown to be sensitive to HINSlight exposure, including important pathogens and food spoilage micoorganisms. The study has confirmed that HINS-light has the capability to be used for the control of a wide range of microorganisms in environmental decontamination applications, and thereby has the potential to contribute to an overall reduction in the numbers of HAI and foodborne illnesses.

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Wong, Karen K. L. « Intra-pulpal thermal effects of dental lasers and high-intensity lights during light-activated tooth whitening and resin polymerisation on human teeth / ». [St. Lucia, Qld.], 2002. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16897.pdf.

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Kjellsson, Lindblom Tor. « Relativistic light-matter interaction ». Doctoral thesis, Stockholms universitet, Fysikum, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-147749.

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During the past decades, the development of laser technology has produced pulses with increasingly higher peak intensities. These can now be made such that their strength rivals, and even exceeds, the atomic potential at the typical distance of an electron from the nucleus. To understand the induced dynamics, one can not rely on perturbative methods and must instead try to get as close to the full machinery of quantum mechanics as practically possible. With increasing field strength, many exotic interactions such as magnetic, relativistic and higher order electric effects may start to play a significant role. To keep a problem tractable, only those effects that play a non-negligible role should be accounted for. In order to do this, a clear notion of their relative importance as a function of the pulse properties is needed. In this thesis I study the interaction between atomic hydrogen and super-intense laser pulses, with the specific aim to contribute to the knowledge of the relative importance of different effects. I solve the time-dependent Schrödinger and Dirac equations, and compare the results to reveal relativistic effects. High order electromagnetic multipole effects are accounted for by including spatial variation in the laser pulse. The interaction is first described using minimal coupling. The spatial part of the pulse is accounted for by a series expansion of the vector potential and convergence with respect to the number of expansion terms is carefully checked. A significantly higher demand on the spatial description is found in the relativistic case, and its origin is explained. As a response to this demanding convergence behavior, an alternative interaction form for the relativistic case has been developed and presented. As a guide mark for relativistic effects, I use the classical concept of quiver velocity, vquiv, which is the peak velocity of a free electron in the polarization direction of a monochromatic electromagnetic plane wave that interacts with the electron. Relativistic effects are expected when vquiv reaches a substantial fraction of the speed of light c, and in this thesis I consider cases up to vquiv=0.19c. For the present cases, relativistic effects are found to emerge around vquiv=0.16c .

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Tammineedi, Chatrapati Veera Raghava Kumar. « EFFECT OF UV-C LIGHT, HIGH INTENSITY ULTRASOUND AND NONTHERMAL ATMOSPHERIC PLASMA TREATMENTS ON THE ALLERGENICITY OF MAJOR COW MILK PROTEINS ». OpenSIUC, 2012. https://opensiuc.lib.siu.edu/theses/921.

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Milk is one of the eight major food allergens. Cow's milk allergy is the most common allergy in children under 2 years of age. About 1.6 to 2.8 percent of children under this age are reported to have cow's milk allergy. Casein, β-lactoglobulin and α-lactalbumin are major milk protein allergens. Nonthermal treatments like high intensity ultrasound, ultraviolet (UV) light and nonthermal plasma treatments have been reported in the literature to be effective in reducing the allergenicity of different food proteins. Hence it was expected for these treatments to reduce cow milk allergenicity. The objective of this study was to investigate the effect of high intensity ultrasound, nonthermal atmospheric plasma and UV-C light treatments in reducing the allergenicity of isolated major milk proteins. Sonics Vibracell VC 505 ultrasonic liquid processor was used to perform high intensity ultrasound treatments. UV light treatments were performed using a DDK Scientific Corporation UV tunnel. A nonthermal atmospheric plasma setup assembled in Department of Microbiology lab was used to perform plasma treatments. Samples were analyzed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) to estimate the change in protein concentration and enzyme linked immuno sorbent assays (ELISA) to observe the change in IgE binding. A one-way analysis of variance was conducted to evaluate the relationship between treatment time and percent IgE binding at 95% confidence level. Further investigation was conducted with nuclear magnetic resonance (NMR) spectroscopy on treated casein to assess any change in the structure of protein. SDS-PAGE results for ultrasound and plasma treatments didn't show any change in gel band intensities for casein, β-lactoglobulin and α-lactalbumin indicating no significant change in protein concentration. Ci-ELISA analysis showed that there was no significant difference (p>0.05) in IgE binding values for control and treated samples in ultrasound and plasma treatment conditions tested in this study. The intensities of all the three protein bands in SDS-PAGE gel were reduced by UV-C light treatment at 15 min treatment time. In Ci-ELISA, there was a significant difference (p< 0.05) in IgE binding values for control and treated samples and a reduction in allergenicity of proteins (25% reduction for casein and 28% reduction for whey protein fractions) was observed. Further investigations using in vivo clinical trials need to be conducted to confirm this result. NMR results didn't show any noticeable changes in the structures of casein with all three different treatments. In conclusion, UV-C light treatment can reduce the allergenicity of isolated major milk proteins to some extent. High intensity ultrasound and nonthermal atmospheric plasma treatments failed to generate effective results for reducing allergenicity at the conditions tested in this study. Higher intensity and longer treatment conditions might yield better results with ultrasound treatment. Different power and gas flow rates used to generate plasma with direct exposure of proteins might yield better results towards reducing the allergenicity of major milk allergens.

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Köhler, Christian [Verfasser], Jan-Michael [Akademischer Betreuer] Rost, Stefan [Akademischer Betreuer] Skupin et Luc [Akademischer Betreuer] Berge. « Ultrashort Light Sources from High Intensity Laser-Matter Interaction / Christian Köhler. Gutachter : Jan-Michael Rost ; Luc Bergé. Betreuer : Jan-Michael Rost ; Stefan Skupin ». Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2012. http://d-nb.info/1068443243/34.

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De, Schutter Alice, et Karin Markendahl. « Using blue light reflectance from high-resolution images (6000 dpi) of Scots pine tree rings to reconstruct three centuries of Scottish summer temperatures ». Thesis, KTH, Hållbar utveckling, miljövetenskap och teknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-297369.

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Advances in scanner technology have made it possible to obtain high resolution (6000 dpi) images of tree samples. Due to the images’ increased capability of resolving anatomical wood structures, the new technology could be of benefit to dendroclimatology. This study attempts to expand on Rydval et al.’s (2017) previous 800 years reconstruction of Scottish summer temperatures by assessing whether a higher image resolution of samples has the ability to improve the accuracy of the region’s temperature reconstruction. Two independent blue intensity (BI) chronologies, based on differing image resolutions (6000 dpi and 2400 dpi) of Scots pine samples, were developed and subjected to standard detrending procedures. Raw data from Rydval et al.’s (2017) prior study was used to develop the chronology which was based on the 2400 dpi images. On the other hand, newly acquired data was utilized for the other chronology. In order to resolve the primary question that this paper explores, the characteristics and strength of the two BI chronologies’ climatic signals were compared. In addition, the newly acquired data was used to develop a 318 years reconstruction of mean July/August temperatures for Scotland. Calibrations against meteorological data indicated that the improved image resolution did not generate a positive effect on the chronology’s ability to retain a reliable climatic signal. The study’s findings were thus inconclusive in showing that a higher image resolution of Scots pine samples improves the accuracy of temperature reconstructions for Scotland. Future studies are encouraged to investigate the applicability of dendroclimatic computer softwares (i.e. CooRecorder) with regard to a high image resolution. From a broader perspective, this study contributes to setting climate change in a more accurate long term spatiotemporal context. This is crucial in predicting future climate variability, as well as understanding the role and extent of anthropogenic forcing.
Framsteg inom skannerteknik har gjort det möjligt att få bilder av trädprover med hög upplösning (6000 dpi). På grund av bildernas ökade förmåga att lösa anatomiska träd strukturer kan den nya tekniken vara till nytta för dendroklimatologi. Denna studie strävar mot att utveckla Rydval et al.s (2017) tidigare 800 års rekonstruktion av skotska sommartemperaturer genom att bedöma om en högre bildupplösning av prover har förmågan att förbättra noggrannheten för regionens temperaturrekonstruktion. Två oberoende blåintensitet (BI) -kronologier, baserade på olika bildupplösningar (6000 dpi och 2400 dpi) av skotska träprover, framtogs och utsattes för standardförfaranden. Rådata från Rydval et al.s (2017) tidigare studie användes för att utveckla kronologin som baserades på 2400 dpi-bilderna. Å andra sidan användes nyförvärvade data för den andra kronologin. För att besvara den primära frågan som denna studie undersöker jämfördes egenskaperna och styrkan hos de två BI-kronologins klimat signaler. Dessutom används de nyförvärvade uppgifterna för att utveckla en 318 års rekonstruktion av genomsnittliga juli/augusti temperaturer för Skottland. Kalibreringar mot meteorologiska data indikerade att den förbättrade bildupplösningen inte genererade en positiv effekt på kronologins förmåga att behålla en pålitlig klimat signal. Studiens resultat var således otvetydiga när de visade att en högre bildupplösning av skotsk tallprover förbättrar noggrannheten i temperatur rekonstruktioner för Skottland. Framtida studier uppmuntras att undersöka användbarheten av dendroklimatiska datorprogram (dvs CooRecorder) med avseende på en ultrahög bildupplösning. Ur ett bredare perspektiv bidrar denna studie till att placera klimatförändringarna i ett mer exakt långsiktigt rumsligt tidsmässigt sammanhang. Detta är avgörande för att förutsäga framtida klimatvariationer samt förstå rollen och omfattningen av antropogen tvingande.

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Schuster, Maja [Verfasser], Ralph [Akademischer Betreuer] Bock, Reimo [Akademischer Betreuer] Zoschke, Ralph [Gutachter] Bock, Kristina [Gutachter] Kühn et Bettina [Gutachter] Bölter. « High resolution decoding of the tobacco chloroplast translatome and its dynamics during light-intensity acclimation / Maja Schuster ; Gutachter : Ralph Bock, Kristina Kühn, Bettina Bölter ; Ralph Bock, Reimo Zoschke ». Potsdam : Universität Potsdam, 2020. http://d-nb.info/1237319994/34.

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Sutherland, Julia Robin Miller. « Phase-Matching Optimization of Laser High-Order Harmonics Generated in a Gas Cell ». Diss., CLICK HERE for online access, 2005. http://contentdm.lib.byu.edu/ETD/image/etd880.pdf.

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Scott, George. « Hormetic UV treatments for control of plant diseases on protected edible crops ». Thesis, Loughborough University, 2017. https://dspace.lboro.ac.uk/2134/28305.

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Hormesis is a dose response phenomenon where low doses of a stress bring about a positive response in the organism undergoing treatment. UV-C hormesis has been known for over three decades and has a broad range of benefits on postharvest produce. Benefits include increased nutritional content, delayed chlorophyll degradation and disease resistance. The beneficial effects have been observed on many varieties of fresh produce including climacteric and non-climacteric fruit, tubers, salads and brassicas. The majority of previous studies have used low-intensity (LIUV) UV-C sources. LIUV sources require lengthy treatment times, which are in the region of 6 minutes for tomato fruit. This has, in part, prevented the commercial application of this technique. High-intensity, pulsed polychromatic light (HIPPL) sources, however, have recently been developed. HIPPL sources may have the potential to drastically reduce treatment times and increase their commercial viability. It was shown, here, that the use of HIPPL can control disease (reduce disease progression) caused by Botrytis cinerea and Penicillium expansum and also delay ripening on tomato fruit. Both disease control and delayed ripening were at similar levels for LIUV and HIPPL treatments on mature green fruit. The HIPPL treatments used in these studies can reduce treatment times for tomato fruit by 97.3%. Both HIPPL and LIUV treatments elicit local responses irrespective of the treatment orientation and tomato fruit, therefore, require full surface irradiation. Furthermore, UV-C in the HIPPL source is not required for disease control or delayed ripening. It does, however, contribute approximately 50% towards the total observed effects. Investigations into the mechanisms underpinning postharvest HIPPL and LIUV hormesis, on tomato fruit, identified that the expression of genes involved in plant hormone biosynthesis, defence, secondary metabolism and ripening were affected. This indicates that disease control is achieved through induced resistance. Changes to expression, following treatment, were highly similar for both HIPPL and LIUV treatments and were mediated by salicylic acid, jasmonic acid and ethylene. This may lead to broad range resistance against necrotrophic and biotrophic pathogens as well as abiotic stresses and herbivorous pests. Recently, the exposure of foliage to UV-C has been shown to induce resistance against B. cinerea on Arabidopsis thaliana. The horticultural applications of such treatments, however, have not been explored. Pre-harvest treatments of lettuce in the glasshouse showed variation in damage threshold and optimal treatment to control disease following LIUV and HIPPL treatment. Further sources of variation included the cultivar, pathogen of interest and the point that treatment was applied during the year. Using a controlled environment allowed seasonal variation to be mitigated and both HIPPL and LIUV treatments controlled disease against B. cinerea. For pre-harvest treatments to be a success in the glasshouse, further studies into how both biotic and abiotic factors influence treatment is required. To circumvent the problems associated with pre-harvest treatments and environmental variation in the glasshouse, LIUV seed treatments were performed on tomato. Control of B. cinerea was established with an approximately 10% reduction in incidence and disease progression with a 4 kJ/m2 treatment. When monitoring the effect of treatment on germination and early seedling development it was also identified that an 8 kJ/m2 treatment led to biostimulation of germination and root and shoot growth.

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Gobé, Alexis. « Méthodes Galerkin discontinues pour la simulation de problèmes multiéchelles en nanophotonique et applications au piégeage de la lumière dans des cellules solaires ». Thesis, Université Côte d'Azur, 2020. http://www.theses.fr/2020COAZ4011.

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L’objectif de cette thèse est l’étude numérique du piégeage de la lumière dans des cellules solaires nanostructurées. Le changement climatique est devenu une problématique majeure nécessitant une transition énergétique à court terme. Dans ce contexte, l'énergie solaire semble être une source énergétique idéale. Cette ressource est à la fois scalable à l’échelle planétaire et écologique. Afin de maximiser sa pénétration, des travaux visant à augmenter la quantité de lumière absorbée et à réduire les coûts liés à la conception des cellules sont nécessaires. Le piégeage de la lumière est une stratégie qui permet d’atteindre ces deux objectifs. Son principe consiste à utiliser des texturations nanométriques afin de focaliser la lumière dans les couches de semi-conducteur absorbantes. Dans ce travail, la méthode de Galerkine Discontinue en Domaine Temporel (DGTD) est introduite. Deux développements méthodologiques majeurs, permettant de mieux prendre en compte les caractéristiques des cellules solaires, sont présentés. Tout d'abord, l’utilisation d’un ordre d’approximation local est proposé , basé sur une stratégie de répartition particulière de l’ordre. Le deuxième développement est l’utilisation de maillage hybride mixant ses élements hexahédriques structurés et tétrahédriques non structurés. Des cas réalistes de cellules solaires issus de la littérature et de collaborations avec des physiciens du domaine du photovoltaïque permettent d'illustrer l' apport de ces développements. Un cas d’optimisation inverse de réseau de diffraction dans une cellule solaire est également présenté en couplant le solveur numérique avec un algorithme d’optimisation bayésienne. De plus, une étude approfondie des performances du solveur a également été réalisée avec des modifications méthodologiques pour contrer les problèmes de répartition de charge. Enfin, une méthode plus prospective, la méthode Multiéchelle Hybride-Mixte (MHM) spécialisée dans la résolution de problème très fortement multiéchelle est introduite. Un schéma en temps multiéchelle est présenté et sa stabilité prouvée
The objective of this thesis is the numerical study of light trapping in nanostructured solar cells. Climate change has become a major issue requiring a short-term energy transition. In this context, solar energy seems to be an ideal energy source. This resource is both globally scalable and environmentally friendly. In order to maximize its penetration, it is needed to increase the amount of light absorbed and reduce the costs associated with cell design. Light trapping is a strategy that achieves both of these objectives. The principle is to use nanometric textures to focus the light in the absorbing semiconductor layers. In this work, the Discontinuous Galerkin Time-Domain (DGTD) method is introduced. Two major methodological developments are presented, allowing to better take into account the characteristics of solar cells. First, the use of a local approximation order is proposed, based on a particular order distribution strategy. The second development is the use of hybrid meshes mixing structured hexahedral and unstructured tetrahedral elements. Realistic cases of solar cells from the literature and collaborations with physicists in the field of photovoltaics illustrate the contribution of these developments. A case of inverse optimization of a diffraction grating in a solar cell is also presented by coupling the numerical solver with a Bayesian optimization algorithm. In addition, an in-depth study of the solver's performance has also been carried out with methodological modifications to counter load balancing problems. Finally, a more prospective method, the Multiscale Hybrid-Mixed method (MHM) specialized in solving very highly multiscale problems is introduced. A multiscale time scheme is presented and its stability is proven

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MUZZIOTTI, GIL DAYANA ISABEL. « Physiological response of the anoxygenic photosynthetic bacterium Rhodopseudomonas palustris 42OL to high light intensity ». Doctoral thesis, 2016. http://hdl.handle.net/2158/1028530.

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This thesis is constituted of an introductive section given detailed information about the metabolic versatility of purple non sulfur bacteria. An exhaustive description of the photo-fermentation process in purple non sulfur bacteria is also offered, with particular consideration to the conditions needed to produce hydrogen. The acclimation (chromo-acclimation) to high light intensities in purple non sulfur bacteria is detailed described, and the role of photo-pigments into this process is highly considered. Moreover, a short description of all ways to dissipate the excess of energy by photosynthetic organisms, is included in this introduction. The use of different techniques to understand the molecular/ energetic status of the photosynthetic unit is presented, with particular attention to Pulse- Amplitude- modulation (PAM) fluorescence and Saturation Pulse Method of Quenching Analysis. In this section, a general view regarding the inhomogeneity problems of light distribution during the photo- fermentation process using purple non sulfur bacteria is offered. Furthermore, short statements about one topic with a few references in literature is described, i.e. production of hydrogen as a way to discard the excess of reducing power generated as a result of high light intensities exposure. The main aim of this thesis was to study the behavior of the purple non sulfur bacterium Rhodopseudomonas palustris strain 42OL to different culturing conditions illuminated at high light intensities, with particular interest to the production of hydrogen as a way to dispose the excess of reductants and as a mechanism to preserve a well physiological status. Besides, the acclimation to high light intensities in this strain was also one of the main objectives to be studied, particularly the trend of photo- pigments.

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Saremi, Ahmad Reza. « Determination of human visual capabilities in the identification of the color of highway signs under a combination of vehicle headlamp and high intensity discharge light sources ». Thesis, 1990. http://hdl.handle.net/1957/37992.

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A standardized color code is used to aid the driver in the prompt recognition of highway signs. At night, these signs are illuminated by various light sources including the headlights and other fixed light sources. These light sources may distort the appearance of the colors of the signs at night. The first objective of this study was to provide information about human capabilities with respect to the recognition of different colors under daytime and nighttime lighting. The second objective was to examine the effect of changing the specifications for highway colors from the Federal Highway Administration (FHWA) standards to the American National Standards (ANSI) safety color specifications. A laboratory experiment was conducted in which subjects named the perceived colors of retroreflective signs viewed under daytime and nighttime lighting. Forty subjects from four different age groups representing the driving population participated in the study. Three color samples (red, orange, and yellow) in three different grades (engineering grade, high intensity grade, and diamond grade), and two different color specifications (FHWA and ANSI) were used. Four different fixed light sources (clear mercury, coated mercury, coated metal halide, and high pressure sodium) were used for illuminating the signs. For the nighttime condition, two headlights were used (metal halide and tungsten halogen). Daytime lighting was simulated using a fluorescent D-65 light source. Response times as well as correct responses for naming the colors were collected for each subject. Significant differences were found for nighttime versus daytime viewing of the signing materials. In general, for nighttime viewing, red and orange colors were identified faster than yellow color samples. In most cases, FHWA colors were identified significantly more accurately and faster than the ANSI colors. The coated metal halide headlight performed better than the other fixed light sources. There was no significant difference found between the tungsten halogen and the metal halide headlights.
Graduation date: 1991

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(9779699), Romeo Batacan. « The effect of different intensities of physical activity and diet on cardiometabolic markers, cardiac and vascular function, and gut microbiota ». Thesis, 2016. https://figshare.com/articles/thesis/The_effect_of_different_intensities_of_physical_activity_and_diet_on_cardiometabolic_markers_cardiac_and_vascular_function_and_gut_microbiota/13387199.

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Cardiometabolic disorder (CMD) has progressively become a global public health concern because of its association with increased risk of developing cardiovascular disease (CVD) and diabetes. Recent studies suggest that light-intensity training (LIT) and high-intensity interval training (HIIT) can induce physiological adaptations that may reduce CMD risk whilst sedentary behaviour has been reported to increase CMD risk. However, the exact cardiometabolic consequences of sedentary behaviour, LIT and HIIT, and the underlying mechanisms behind the distinct health outcomes they produce remains to be elucidated.

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Sivis, Murat. « Extreme-ultraviolet light generation in plasmonic nanostructures ». Doctoral thesis, 2013. http://hdl.handle.net/11858/00-1735-0000-0022-5E08-0.

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