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Dissertations / Theses on the topic 'Light intensity'
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Edmonds, Anne, University of Western Sydney, of Arts Education and Social Sciences College, and School of Contemporary Arts. "Light as surface and intensity." THESIS_CAESS_CAR_Edmonds_A.xml, 2003. http://handle.uws.edu.au:8081/1959.7/561.
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Light Intensity and Surface is the title of this PhD art exhibition where I explore through paintings, the world of my own encounter with the radiant light of the Linear Accelerator used in treatment of women with breast cancer. This engagement with the world of light technology encompasses oncologists, physicists and women who extended their personal experience to inform my artwork and contribute to the theoretical connections made in this thesis. The contribution of this thesis lies in how the lecture The Origin of the Work of Art by philosopher Martin Heidegger can be applied to a reading of great artworks that are separated in time, space and culture but connected in their subject: Light. It was his philosophy that helped shape the connections between where art originates and what springs from the artwork itself. The concept of light in the title of this thesis refers to Heidegger’s notion of the clearing seins Lichtung-the lighting centre- the medium that holds one being to another from where the idea for an artwork springs in the artist. Surface relates to the attunement of artists throughout history to the new particularly in the science of controlling light which influences the way artists achieve the material appearance of their artwork. Intensity refers to the level of openness to the mystery of light in both physicists and artists to create and control some thing that stabilises a community and remains a source of wonder. This thesis demonstrated how artists have responded to the new light technology with a way of seeing that created a depth dimension that bridges cultural worlds to unearth the breath of something often most effectively communicated by being silentDoctor of Philosophy(PhD)
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Edmonds, Anne B. "Light as surface and intensity /." View thesis, 2003. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20050923.103216/index.html.
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Thesis (Ph.D.) -- University of Western Sydney, 2003."Doctor of Philosophy, Visual and Contemporary Arts, University of Western Sydney" Supervisor, Graham Marchant; co-supervisor, Phillip Kent. Bibliography : leaves 214-221.
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Wölfl, Friedrich. "Intensity noise studies of semiconductor light emitters." Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342990.
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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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Beeler, Matthew. "Intensity Correlations of Light Scattered from Cold Atom Clouds." Miami University Honors Theses / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=muhonors1111085986.
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Paee, Furzani. "Photosynthetic acclimation to lower light intensity in Arabidopsis thaliana." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/photosynthetic-acclimation-to-lower-light-intensity-in-arabidopsis-thaliana(39ab9c6f-f1f2-463c-93c2-32210b7d8f4e).html.
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Photoacclimation is a process by which photosynthetic capacity is regulated in response to environmental adjustments in terms of light regime. Photoacclimation is essential in determining the photosynthetic capacity to optimize light use and to avoid potentially damaging effects. Previous work in our laboratory has identified a gene, gpt2 (At1g61800) that is essential for plants to acclimate to an increase in growth irradiance. Furthermore, we observed that the accession Columbia-0 (Col-0) is unable to respond to increases in light. Therefore, a Quantitative Trait Locus (QTL) mapping analysis was performed in Landsberg erecta (Ler)/Columbia (Col) recombinant inbred line population to identify novel genes responsible for this variation to acclimation. In order to investigate the photoacclimation in Arabidopsis thaliana, photosynthetic capacity was measured in plants of the accession Wassileskija (WS) and in plants lacking expression of the gene At1g61800 (WS-gpt2) during acclimation from high to low light. Plants were grown for 6 weeks under high light (400 μmol.m-2.s-1) and half of them were transferred to low light (100 μmol.m-2.s-1) after six weeks. Gas exchange measurements were performed in order to measure the maximum capacity for photosynthesis. Acclimation to a decrease in light resulted in a decrease in the photosynthetic capacity in WS and WS-gpt2 plants. This shows that under lower or limiting light, photosynthesis was slowed down. Chlorophyll fluorescence analysis was carried out to measure changes in the quantum efficiency of PSII (ΦPSII) and non-photochemical quenching (NPQ) during acclimation. ΦPSII decreased in both WS and WS-gpt2 plants showing that under low light, PSII is more saturated. However, it was found that there was no significant changes in NPQ level for both WS and WS-gpt2. To estimate the total chlorophyll and chl a/b ratio, a chlorophyll composition analysis was performed. There was no significant changes in the total chlorophyll for both WS and WS-gpt2. However, the chlorophyll a/b ratio was seen to be decreased in low light plants representing an increase in light harvesting complexes relative to reaction centre core. Plants of WS and WS-gpt2 were also grown under natural variable light in an unheated greenhouse in Manchester, UK. This experiment was carried out to study the photosynthetic acclimation of plants under fluctuating light condition. A preliminary work on gene expression of gpt2 was conducted by doing reverse transcriptase PCR (RT-PCR). It shows that the gene expression of gpt2 decreased following transfer to low light plants in WS. Microarray analysis was also performed to investigate the role of GPT2 (if any) and to identify any potential gene that is important in high to low light acclimation.
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Thompson, Claire Elisabeth. "The effects of light intensity on turkey eyes and behaviour." Thesis, University of Leeds, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250913.
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Shi, Wen. "The Age-Related Dynamic Accommodative Characteristics Associated With Light Intensity and Chromaticity." Diss., Virginia Tech, 2007. http://hdl.handle.net/10919/30150.
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Visual accommodation plays a critical role in one's visual perception and activities of daily living. The age-related accommodation loss poses a greater risk to older adults' safety and independence. Although extensive effort has been made to study the effects of aging on accommodation, the relationship between aging and the dynamic aspects of accommodation is still unknown. Furthermore, since light is the carrier of external stimuli for accommodation, it is of value to assess the influences of light on the age-related accommodation loss. Therefore, a study was conducted to investigate the age-related dynamic accommodative characteristics under various conditions of the intensity and chromaticity of light. To ascertain the effects of aging, ten individuals from each of three age groups (i.e., younger group: 20 to 29 years old, middle-aged group: 40 to 49 years old, and older group: 60 to 69 years old) were recruited, and their dynamic accommodation responses were examined. Laboratory experiments were designed to measure accommodation in a simulated condition where a person must alternate from viewing outside to reading the dashboard while driving. It was hypothesized that the advancing of age will lead to the deterioration of oneâ s dynamic accommodative performance, and light of different intensities and chromaticities will interact with the effects of aging on accommodation.
The results of the study supported the above hypotheses. It was found that the advancing of age, the decrease of light intensity, and the change of light chromaticity all led to the alteration of one's dynamic accommodative performance. The present study concluded with a biomechanical and neural model elaborating the mechanism of an accommodation process within the scope of the study.Ph. D.
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Pettersson, Rimgard Belinda. "Light Intensity Dependence of Charge Recombination in Dye-Sensitized NiO films." Thesis, Uppsala universitet, Fysikalisk kemi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-227635.
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Bell, Stuart James. "The effect of light intensity and temperature on photocatalytic water splitting." Thesis, Queensland University of Technology, 2011. https://eprints.qut.edu.au/50960/1/Stuart_Bell_Thesis.pdf.
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Photocatalytic water splitting is a process which could potentially lead to commercially viable solar hydrogen production. This thesis uses an engineering perspective to investigate the technology. The effect of light intensity and temperature on photocatalytic water splitting was examined to evaluate the prospect of using solar concentration to increase the feasibility of the process.
P25 TiO2 films deposited on conducting glass were used as photocatalyst electrodes and coupled with platinum electrodes which were also deposited on conducting glass. These films were used to form a photocatalysis cell and illuminated with a Xenon arc lamp to simulate solar light at intensities up to 50 suns. They were also tested at temperatures between 20°C and 100°C.
The reaction demonstrated a sub-linear relationship with intensity. Photocurrent was proportional to intensity with an exponential value of 0.627. Increasing temperature resulted in an exponential relationship. This proved to follow an Arrhenius relationship with an activation energy of 10.3 kJ mol-1 and a pre-exponential factor of approximately 8.7×103.
These results then formed the basis of a mathematical model which extrapolated beyond the range of the experimental tests. This model shows that the loss of efficiency from performing the reaction under high light intensity is offset by the increased reaction rate and efficiency from the associated temperature increase. This is an important finding for photocatalytic water splitting. It will direct future research in system design and materials research and may provide an avenue for the commercialisation of this technology.
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Paniagua, Diaz Alba Maria. "Light in scattering media : active control and the exploration of intensity correlations." Thesis, University of Exeter, 2018. http://hdl.handle.net/10871/33161.
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When light encounters scattering materials such as biological tissue, white paint or clouds, it gets randomly scattered in all directions, which traditionally has been seen as a barrier for imaging techniques (reducing their resolution) or sensing, due to the reduction of the penetration depth of light. However, in recent years it has been shown that scattering might not necessarily be an impediment, and that the knowledge of the properties of multiple scattering can be indeed useful for imaging, sensing and other applications. In the first part of this thesis (Chapters 2 to 5) we study the implications of manipulating the light incident on a multiply scattering material. We experimentally show how by actively controlling the output light of a bad quality laser we manage to not only improve its beam quality, but also in an energy-efficient way, in comparison with traditional methods. In a different experiment presented in this thesis, we show how the active control of the light incident on a scattering material can be useful to improve sensing through scattering media, by means of increasing the transmission and energy deposited inside (Chapter 5). In the final part of the thesis we present the first experimental observation of intensity correla- tions between transmitted and reflected patterns from a scattering material (Chapter 6), exploring how it depends on the parameters of the scattering medium. In the last part of the thesis (Chapter 7) we present a new imaging technique based on the use of the intensity correlations described in the previous chapter, opening new possibilities to non-invasive imaging through highly scattering materials.
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Akbari, Pegah. "Exploration of Heat Strain during Light to Moderate Intensity Exercise throughout Pregnancy." Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/38335.
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Regular physical activity is recommended in healthy pregnancies and has been shown to mitigate adverse pregnancy outcomes. Despite the benefits, many women do not adhere to the recommendations due to concerns of exercise-induced heat stress and the dangers it could pose to the developing fetus. While the majority of the concerns raised are not grounded in evidence, currently there are no studies that directly examine the isolated influence of pregnancy on metabolic heat production resulting from physical activity. Additionally, despite the prevalent use of psycho-physical tools in clinical settings, there is a scarcity of literature exploring the relationship between the physiological and perceptual measures of exercise-induced heat strain in the pregnant population. Therefore, objective one of this thesis was to quantify the heat production resulting from light to moderate physical activity (intensities recommended during pregnancy) throughout gestation. Secondly, in objective two, physiological and perceptual measures of thermal strain were compared and assessed throughout pregnancy. In evaluating the change in heat production resulting from exercise (objective one), 10 non-pregnant control (30±1 yrs; BMI=22.3±0.8 kg/m2) and 10 pregnant (32±1 yrs; pre-pregnancy BMI=22.8±0.8 kg/m2) women performed a seven stage submaximal walking test in a thermal controlled chamber (23ºC). Testing was performed during their 1st (T1, 12-16 wks), 2nd (T2, 24-28 wks) and 3rd (T3, 34-38 wks) trimester of pregnancy while metabolic heat production was measured through indirect calorimetry. To assess the changes in thermal and perceptual strain (objective two), 16 non-pregnant control (32±1 yrs; BMI=22.7±0.7 kg/m2), and 20 pregnant (32±1; pre-pregnancy BMI=23.2±0.6 kg/m2) women underwent a graded walking exercise protocol at T2 and T3. Over the course of this test, heart rate, tympanic temperature (Ttymp), skin temperature (Tskin), rate of perceived exertion (RPE, 20-point scale) and thermal sensation (9-point scale) were assessed. Findings from this thesis show that for the same given progressive exercise test, women in T1 experienced similar metabolic heat production to their non-pregnant counterparts. However, as pregnancy progressed, women exhibited on average, a 7-8% increase in heat production per trimester of pregnancy that can be accounted for by weight gain. Further, at baseline conditions, heart rate responses increased with pregnancy, while Ttymp remained unchanged and Tskin decreased. In response to exercise, the magnitude of change in heart rate, Ttymp and Tskin did not differ between gestational conditions. Finally, a strong correlation was identified between heart rate and RPE throughout pregnancy, while thermal sensation only directly correlated with Ttymp and not Tskin. Overall, the present findings suggest that while the same progressive exercise test results in greater levels of heat production as pregnancy progresses, this is not observed in physiological or perceptual measures of heat strain. Rather, findings of this thesis support the notion of improved thermoregulatory responses to account for the increase in metabolic heat production. Moreover, the present thesis provides support for the use of the RPE and thermal sensation scales as effective psycho-physical tools in the pregnant population under conditions of light to moderate exercise in normothermic conditions.
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Xu, Yu. "Light intensity attenuation-based fibre-optic chemical sensors : theoretical analyses and design studies." Thesis, University of Leicester, 2000. http://hdl.handle.net/2381/30184.
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In the thesis light intensity attenuation-based fibre-optic chemical sensors are investigated. The investigation proceeds along two lines: theoretical analyses and design studies. Both intrinsic and extrinsic types of sensors are discussed from both aspects. The theoretical analyses are concentrated on the construction of theoretical models and numerical calculations, which were previously not well developed but have been attracting a great deal of attention of researchers for some time. Under this topic, fibre-optic evanescent wave absorption sensors and fibre-optic surface plasmon resonance (SPR) sensors are studied as examples of the intrinsic type of sensors, and two-wavelength Beer-Lambert law based fibre-optic sensors as the extrinsic example. The design studies are concentrated on the design of novel types of sensors which have potentially valuable applications. As the intrinsic type of sensors, novel types of fibre-optic surface plasmon resonance (SPR) chemical sensors are proposed and studied in both point and distributed systems. A fibre-optic sensor for concentration determination of the infusible anaesthetic Propofol is studied in detail as an example of an extrinsic type of sensor.
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Skinner, Daniel George. "A sudden blaze of light : low intensity democracy in Hong Kong, 1978-1997." Title page, abstract and table of contents only, 1998. http://web4.library.adelaide.edu.au/theses/09ARM/09arms628.pdf.
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Bibliography: leaves 269-327. "This dissertation investigates the political reforms initiated by the Hong Kong colonial government between 1978-1996 in light of Hong Kong's reversion to Chinese sovereignty on Juy 1, 1997." --Abstract
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Tinsley, Matthew. "Experimenter familiarity and light intensity effects on open field behaviour of Rattus norvegicus /." Title page, contents and abstract only, 1995. http://web4.library.adelaide.edu.au/theses/09SPS/09spst592.pdf.
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Çelik, Selen. "Living withlow intensity and warm light:Designing light in living roomsthrough Nordic daylight qualities." Thesis, KTH, Ljusdesign, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-280063.
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This thesis concentrates on lighting preferencesin living rooms concerning Nordic lightqualities in winter. Living rooms are spaceswhere we relax, communicate, eat, gather andread. Lighting in living rooms gives hints aboutour perception and character.Nordic countries, there is something uniquethan others; use of light and daylight sensiblyand wisely. In the Nordic countries, where thelight and darkness change dramatically betweenthe seasons, the transitions have a specialsignificance. Higher the latitude, twilight hoursare getting longer, and it creates a homogeneoustransition between daylight and night.The thesis consists of literature research andsurvey. Literature research concerning the topicbriefly explains different aspects of the color oflight, its effects on performance, basic lightingsolutions and Nordic daylight qualities in winter.Furthermore, the culture of window lightingand use of daylight as a background are studiedand added to the survey in order to understandthe relation between indoor and outdoor lightqualities from the participants’ perspective.The survey with twenty-one questions andseventy-two participants tries to evaluatehow Nordic light affects people’s preferences.Evaluation and results followed by thediscussion of desired color temperature, lightinglevel, comfortability under Nordic daylight inwinter. Additionally, paintings from differentseasons help me to understand awareness oflocal daylight and attention of participants.Results show us that the attention people giveto the desired light intensity and colors aremore related to the people’s interests than totheir background, profession and length ofstay in Stockholm. It would be interesting toinvestigate this topic with more people who livein Stockholm more than five years.The concentration of the thesis is understandinghow local daylight conditions can affect people’slighting preferences in their living room.Results will help us to implement the knowledgeand collected information into the lightingdesign process in living rooms in Nordic countries.
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Carter, Robert Hansbrough. "Transmitted light intensity as a nondestructive evaluation technique for glass/epoxy composite laminates." Thesis, This resource online, 1995. http://scholar.lib.vt.edu/theses/available/etd-11242009-020334/.
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Envall, Linus. "Geolocation by Light using Target Tracking." Thesis, Linköpings universitet, Reglerteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-95609.
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In order to understand the migration patterns of migrating birds, it is necessary to understand whenand where to they migrate. Many of these birds are very small and thus cannot carry heavy sensors;hence it is necessary to be able to perform positioning using a very small sensor. One way to do this isto use a light-intensity sensor. Since the sunrise and sunset times are known given time and position onthe earth, it is possible to determine the global position using light intensity. Light intensity increasesas the sun rises. Data sets from several calibration sensors, mainly from different locations in Sweden, have been examinedin different ways in order to get an understanding of the measurements and what affects them. Inorder to perform positioning, it is necessary to know the solar elevation angle, which can be computedif the time and position are known, as is the case for the calibration sensors. This has been utilized toidentify a mapping from measured light intensity to solar elevation angle, which is used to computepseudo-measurements for target tracking, described below. In this thesis, positioning is performed using methods from the field of target tracking. This is doneboth causally (filtering) and non-causally (smoothing). There are certain problems that arise; firstly,the measured light intensity can be attenuated due to weather conditions such as cloudiness, which ismodelled as a time-varying offset. Secondly, the sensor can be shadowed causing outliers in the data.Furthermore, birds are not always in a migratory state, they oftentimes stay in one place. The lattertwo phenomena are modelled using an Interacting Multiple Model (IMM) where they are representedas discrete states, corresponding to different models.
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Beffa, James C., and T. Koryu Ishii. "MILLIMETER WAVE RADIO RESPONDER FOR REMOTE SENSING OF SURFACE CONDUCTIVITY AND LASER LIGHT INTENSITY." International Foundation for Telemetering, 1986. http://hdl.handle.net/10150/615543.
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International Telemetering Conference Proceedings / October 13-16, 1986 / Riviera Hotel, Las Vegas, NevadaA millimeter wave radio responder was evaluated as a remote sensor of surface conductivity and laser light intensity. A 10 mm CdSe photocell was illuminated by a 1/4 mW, 632.8 nm He-Ne laser light. The photocell was not connected to anywhere. The terminals were left open. The photocell was interrogated by a remotely placed millimeter wave radio responder operated with the frequency of 69.6 GHz and the transmitter power of 3 mW. The millimeter wave radio responder was able to sense the radio echo from the surface of the photocell. The laser illuminated area on the photocell was only 2.86% of the entire active area, yet the radio responder output showed up to 15 dB difference between the laser spot on and off from the target. The minimum reflected signal change observed was 0.002 dB by tilting the target 20 degrees from the normal incidence of the millimeterwave beam. This was translated to be 0.025% of surface conductance change on the target. This remote sensing was done using an instrumentation of the sensitivity of !40 dBm. Thus, the usefulness and advantage of employing a millimeter wave radio responder for remote sensing of minute change in the surface conductivity and/or the laser light intensity have been demonstrated in this research.
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Li, Tsai-Chi. "CRYPTOCHROME 1 (CRY1) Is Critical in Mediating Developmental Process in Response to Light Intensity." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1244019693.
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Gaire, Rashmi. "Effect of light intensity on size hierarchy of redroot pigweed and transmission of far-red light through leaves of selected species." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/50037.
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In order to investigate the effects of light intensity on (1) growth, morphology, and size hierarchy of Amaranthus retroflexus, and (2) transmission of far-red (FR) light through leaves lambsquarters (Chenopodium album), redroot pigweed (A. retroflexus) and bush beans (Phaseolus vulgaris), field experiments were conducted using a randomized complete block design with five replications per treatment. Plants were grown under four light intensities (22%, 33%, 55% and 100% of full sunlight) using 3, 2, 1 and 0 layers of mesh screen, respectively. These treatments represented approximately 400, 600, 1,000 and 1,800 µE m−² s−¹ light intensity on a clear day at noon at the Totem Field at UBC. Size hierarchy for plant height significantly increased with decreasing light intensity. Size hierarchy at 22% light intensity was 67% higher compared to that at 100% sunlight. Size hierarchy of shoot biomass was not affected by light level. The magnitude of several growth/morphological characters decreased with decreasing light intensity. Since light treatments were applied to relatively uniform populations, effect of light intensity on size hierarchy could possibly be due to genetic variability within a pigweed population.
In order to study the effect of light intensity on FR transmission through leaves, plants were subjected to four light intensity treatments as described above. Lambsquarters and bean leaves developed at 22% light intensity transmitted higher FR light, compared to those developed at 100% sunlight. There was a weak negative correlation between specific leaf weight and FR transmission in PW (R² = 0.16) compared to bean (R² = 0.78) and lambsquarters (R² = 0.69) leaves. FR transmission from pigweed leaves was generally higher compared to lambsquarters and bean leaves but there was no consistent and/or significant difference in FR transmission through pigweed leaves developed at different light intensities. The leaf position on plant stem did not influence FR transmission in this study. These results show that light intensity influences FR transmission characteristics of leaves and the three species employed in this study differ in this regard. Leaf optical properties as well as leaf area should therefore be considered while assessing plant-plant interactions in mixed populations.Land and Food Systems, Faculty of
Graduate
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Tonetto, Aurélio Fajar. "Efeitos da irradiância e da composição espectral da luz sobre o estabelecimento e desenvolvimento de comunidades de macroalgas lóticas em substratos artificiais /." Rio Claro : [s.n.], 2010. http://hdl.handle.net/11449/87902.
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Orientador: Ciro Cesar Zanini BrancoBanca: Orlando Necchi Junior
Banca: Carla Ferragut
Resumo: Os efeitos provocados pela variação quantitativa e qualitativa da luz incidente sobre a estrutura das comunidades de macroalgas lóticas em riachos da região Centro-Sul do estado do Paraná foram investigados a partir de experimentos utilizando-se amostradores com substratos artificiais que modulam a quantidade e qualidade da luz incidente. Os resultados reveleram que as respostas das divisões algais isoladamente foram mais claras do que àquelas observadas para as comunidades de macroalgas como um todo. As algas verdes mostraram-se melhores adaptadas as condições com maiores energias luminosas. A espécie de cianobactéria registrou clara preferência por comprimentos de onda mais longos (faixa do vermelho). As algas vermelhas apesar de apresentarem baixos valores de abundância, aparentemente, preferiram condições levemente sombreadas e, como as cianobactérias, apresentaram maiores valores de abundância quando submetidas a luz vermelha. Neste contexto, o aparato fotossintético característico de cada divisão algal parece ser determinante para os seus comportamentos ecológicos, uma vez que desempenham funções adaptativas diante das diferentes condições de luminosidade
Abstract: The effects of light intensity and quality on the structure of lotic macroalgal communities in streams from the mid-southern region of Paraná State were investigated using artificial substrata that simulate different levels of light and specific wavelengths. The results showed that the abundance values of each algal divisions were clearer to that observed to global macroalgae communities. The green algae were better adaptated on higher light energies conditions. The cianobacteria species reported a clear preference to longer wavelengths (red light). Red algae, on the other hand, despite of the low abundance values, apparently prefer lightly shaded conditions and like blue-green algae, they showed better colonization on the red light. In this context, the characteristic photosynthetic apparatus of each division seems to be determinant to the ecological behavior of these communities once they play an important adaptative role face to the different light conditions
Mestre
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Strath, Scott J. "The effect of a light-moderate versus hard exercise intensity on health and fitness benefits." Virtual Press, 1998. http://liblink.bsu.edu/uhtbin/catkey/1115726.
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The purpose of this study was to determine the effect of a light-moderate versus hard exercise intensity on health and fitness benefits in a previously sedentary population. Twenty-six subjects, 17 male (mean age 45 + 3 yrs), 9 female (mean age 48 + 3 yrs) with at least one coronary artery disease risk factor volunteered to participate in this study. Subjects underwent laboratory testing comprising of, resting heart rate and blood pressure, body composition, blood lipid analysis and aerobic capacity (V02 ), prior to and 22-32 weeks after participating > 2 days per week in the Adult Physical Fitness Program (APFP) at Ball State University. After an initial exercise prescription subjects self selected an exercise intensity between 40-80% of their maximal heart rate range (MHRR) at which to train. Subjects were then grouped into those who trained at < 60% (light-moderate) and those who trained at > 60% (hard) of their MHRR.Those that self selected a hard training intensity did show a significantly greater decrease in diastolic blood pressure than the light-moderate intensity group. Subjects received a main training effect with a mean decrease in systolic blood pressure (123 ± 2.8 to 119 ± 2.4 mmHg), diastolic blood pressure (78 ± 2.2 to 75 ± 1.7 mmHg), and mean increases for HDL-cholesterol (49 ± 2.5 to 53 ± 2.8 mg/dL), absolute functional capacity (2.676 +.162 to 2.843 +.169 L/min) and relative functional capacity (30.2 ± 1.5 to 32.8 + 1.8 ml/kg/min). In conclusion this study demonstrated health and fitness benefits when training at least 2 days per week with greater effects when training at a hard versus light-moderate intensity with regards to diastolic blood pressure.School of Physical Education
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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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Prayitno, Dwi Sunarti. "The effects of colour and intensity of light on the behaviour and performance of broilers." Thesis, Bangor University, 1994. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387208.
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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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Franz, Mark L. "Local agency traffic sign retroreflectivity case study and model of observed traffic sign light intensity." Morgantown, W. Va. : [West Virginia University Libraries], 2009. http://hdl.handle.net/10450/10473.
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Thesis (M.S.)--West Virginia University, 2009.Title from document title page. Document formatted into pages; contains viii, 85 p. : ill. (some col.), col. map. Includes abstract. Includes bibliographical references (p. 79-82).
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Yang, Ying. "Effects of Temperature, Light Intensity and Quality, Carbon Dioxide, and Culture Medium Nutrients on Growth and Lipid Production of Ettlia oleoabundans." Digital WPI, 2014. https://digitalcommons.wpi.edu/etd-dissertations/42.
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Ettlia oleoabundans, a freshwater green microalga, was grown under different environmental conditions to study its growth, lipid yield and quality for a better understanding of the fundamental physiology of this oleaginous species. E. oleoabundans showed steady increase in biomass under low temperature and low light intensity, and at high temperature lipid cell content significantly increased independent of nitrate depletion. Studies on light quality showed that red light treatment did not change the biomass concentration, but stimulated lipid yield especially oleic acid, the most desirable biodiesel precursor. Moreover, no photoreversibility in lipid production was observed when applying alternating short-term red and far-red lights, which left the phytochrome effect still an open question. In addition, carbon dioxide enrichment via an air sparging system significantly boosted exponential growth and increased carbon conversion efficiency. Finally, a practical study demonstrated the feasibility of growing E. oleoabundans for high lipid production using a diluted agricultural anaerobic waste effluent as the medium. Together, these studies showed the potential of E. oleoabundans as a promising high yield feedstock for the production of high quality biodiesel.
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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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Snyman, LW, Plessis M. Du, and H. Aharoni. "Injection-Avalanche-Based nþpn Silicon Complementary Metal Oxide–Semiconductor Light-Emitting Device (450 – 750 nm) with 2-Order-of-Magnitude Increase in Light Emission Intensity." Japanese Journal of Applied Physics, 2007. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1000813.
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In this paper, we report on an increase in emission intensity of up to 10 nW/mm2 that has been realized with a new novel two
junction, diagonal avalanche control, and minority carrier injection silicon complementary metal–oxide–semiconductor
(CMOS) light emitting device (LED). The device utilizes a four-terminal configuration with two embedded shallow nþp
junctions in a p substrate. One junction is kept in deep-avalanche and light-emitting mode, while the other junction is forward
biased and minority carrier electrons are injected into the avalanching junction. The device has been realized using standard
0.35 mm CMOS design rules and fabrication technology and operates at 9V in the current range 0.1– 3 mA. The optical output
power is about one order of magnitude higher for previous single-junction nþp light-emitting devices while the emission
intensity is about two orders of magnitude higher than for single-junction devices. The optical output is about three orders of
magnitude higher than the low-frequency detectivity limit of silicon p–i–n detectors of comparable dimensions. The realized
characteristics may enable diverse optoelectronic applications in standard-CMOS-silicon-technology-based integrated
circuitry.
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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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Tough, Murray William. "Low-intensity laser light and the recovery from exhaustive eccentric exercise in human elbow flexor muscles." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ52956.pdf.
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Huseby, Oddmund. "Spatio-temporal variation in moose-vehicle collisions: the effect of varying traffic intensity and light conditions." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for biologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-21419.
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In order to find effective mitigating measures against the large number of moose-vehicle collisions (MVCs) in the Nordic countries, it is important to learn more about the underlying mechanisms causing their spatio-temporal variation. While many studies have looked at the effects of varying moose density, traffic volume and weather conditions on the seasonal and yearly variation in MVCs, previous research has rarely studied the same questions based on MVC data collected at the temporal scales of date and hour. However, because the circadian activity of moose is closely related to the variation in daylight, the road-crossing probability of moose may differ between light periods (dusk, dawn, night and daytime) – which timing and extent vary with month and latitude. Conversely, the circadian variation in traffic intensity seems to follow a fixed daily pattern in all of Norway. This indicates that the overlap between high crossing probability and high traffic intensity will show a predictable pattern across months and latitudes. To test this hypothesis, I examined to what extent the probability of MVC in a municipality was related to varying traffic intensity within light period during the year, while simultaneously controlling for spatial variation in moose density (harvest per km2) and traffic volume (number of cars). My results demonstrated that the probability of MVC for a given traffic intensity was lowest during the day, which concurs with previous findings that moose are more active at dawn, dusk and night. However, while the probability of MVC increased with increasing traffic intensity at dawn and night, as expected, the relationship was negative at daytime and dusk. The latter two periods coincide with hours of the day with the on average highest traffic intensity, which may suggest that moose may increasingly perceive roads as barriers when the traffic intensity exceeds a certain level. The circadian relationship also explained parts of the latitudinal and monthly variation in MVCs, particularly in November-January. My findings suggest that high probability of MVC is partly associated with the time of the year when high traffic intensity extends into the dark and twilight periods of the day. These results can be used to provide management authorities and the public better information about when and where an MVC is more likely to occur.
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Paulson, Courtney L. "Using the Haar-Fisz wavelet transform to uncover regions of constant light intensity in Saturn's rings." Honors in the Major Thesis, University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETH/id/1473.
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This item is only available in print in the UCF Libraries. If this is your Honors Thesis, you can help us make it available online for use by researchers around the world by following the instructions on the distribution consent form at http://library.ucf.edu/Systems/DigitalInitiatives/DigitalCollections/InternetDistributionConsentAgreementForm.pdf You may also contact the project coordinator, Kerri Bottorff, at kerri.bottorff@ucf.edu for more information.Bachelors
Sciences
Statistics
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Bryant, Marion Jane. "The influence of soil fertility and light intensity on field layer development in urban secondary woodlands." Thesis, University of Wolverhampton, 2003. http://hdl.handle.net/2436/96313.
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Dias, Rodolfo Liporoni. "Visual ecology of nocturnal bees: how light intensity affects foraging activity in cambuci, a neotropical Myrtaceae." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/41/41134/tde-21082018-082154/.
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The foraging activity of day-active bees often rely on flower availability, light intensity and temperature. However, some bees developed a nocturnal habit and fly during the dusk, dawn and night. We still do not know how these bees cope with environmental factors, especially dimmer light levels, to explore flower earlier than their diurnal relatives. Given that typical bee apposition compound eyes work better in brighter environments and function in their limits in dim-light conditions, we can expect a larger dependence of light intensity for nocturnal groups. Nocturnal and crepuscular bees are frequent visitors of cambuci (Campomanesia phaea, Myrtaceae) in southeastern Brazil. We aimed to investigate how light intensity affects flower visitation of cambuci by nocturnal and crepuscular bees, also controlling for other environmental factors. We counted visits per minute along 30 nights/twilights in 33 cambuci trees from a commercial orchard, measuring the following environmental variables: light intensity, flower availability, temperature, air relative humidity and wind speed. Light intensity is the only variable that explained flower visitation of nocturnal bees in cambuci, which peaks at intermediate light levels that occur around 30 minutes before sunrise. The minimum light intensity threshold to bees start flying is of 0.00024 cd/m2, the first recorded value for nocturnal and crepuscular bees finding flowers in an agro-forest context. Our results highlight for the first time how nocturnal bees rely on light to explore resources and show that the bees light-dependent foraging activity is not always linear, as postulated by previous theoretic models. This is the first step to understand how nocturnal bees react to environmental factors. Our findings also bring concerns about possible negative effects of light pollution at night for cambuci-crepuscular bees interactionO forrageio de abelhas geralmente depende de disponibilidade de flores, intensidade de luz e temperatura. Contudo, algumas abelhas desenvolveram hábitos noturnos e voam durante os crepúsculos e a noite. Não se sabe como essas abelhas lidam com os fatores ambientais, especialmente os reduzidos níveis de luminosidade. Dado que os olhos compostos de aposição de abelhas funcionam melhor em maiores luminosidades, espera-se uma maior dependência da luz para os grupos noturnos. Abelhas noturnas e crepusculares são visitantes frequentes do cambuci (Campomanesia phaea, Myrtaceae) no sudeste do Brasil. Nosso objetivo foi investigar como a intensidade de luz afeta a visitação floral do cambuci por abelhas noturnas e crepusculares, controlada também por outros fatores ambientais. Para isso, contamos as visitas a cada minuto ao longo de 30 noites/crepúsculos em 33 árvores de cambuci em um pomar comercial, medindo as seguintes variáveis ambientais: intensidade de luz, disponibilidade de flores, temperatura, umidade e velocidade do vento. A intensidade de luz foi a única variável que explicou a visitação floral de abelhas noturnas no cambuci, a qual tem um pico em níveis intermediários de luz que ocorrem ao redor de 30 minutos antes do nascer do sol. O limiar mínimo de intensidade de luz para as abelhas começarem a voar foi de 0.00024 cd/m2, o primeiro valor registrado para abelhas noturnas e crepusculares procurando por flores em um contexto agroflorestal. Nossos resultados destacam pela primeira vez como as abelhas noturnas dependem da luz para explorar recursos e mostram que essa dependência, para abelhas em geral, não é sempre linear, como postulado por modelos teóricos prévios. Este é o primeiro passo para entender como abelhas noturnas reagem a fatores ambientais. Nossos dados também trazem alertas para possíveis efeitos negativos da poluição luminosa à noite para a interação entre cambuci e abelhas noturnas
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Thanapisudwong, Thatchai. "The Impact of Raceway Mixing and Light Penetration on Algal Growth." Ohio University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1479910640426105.
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Luk, Wai-ming Albert, and 陸偉明. "Association of light exposure intensity with the quality of sleep and behavioral symptoms in Chinese Alzheimer's disease patients." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/209551.
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Introduction:
Dementia is an age-associated neurodegenerative disorder characterized by a progressive loss of neuro-cognitive function and the emergence of a wide variety of behavioral symptoms. Alzheimer's disease (AD) is the most common types of dementia.
Sleep disturbances in patients with Alzheimer's disease is common and previous studies from North America, Europe and Japan reported light therapy could improve the sleep circadian rhythm ( rest-activity) disturbances in AD. However, there was no previous Chinese study on light exposure and sleep quality nor the circadian rhythm in Chinese Alzheimer's disease patients.
Objective :
The objective of the present study was to investigate the association of light exposure intensity with the quality of sleep and behavioural symptoms in Chinese Alzheimer’s disease (AD) patients
Method:
This was a cross-sectional observational study. 203 Chinese elderly patients with Alzheimer's disease were recruited from the Memory Clinic in Queen Mary Hospital, the University of Hong Kong, from July 2014 to December 2014. Socio-demographic data and comorbid diseases information were collected from all subjects. Their sleep qualities, quantities and conditions of light exposure were recorded with a sleep logbook and light meter. Their cognitive function, disturbing behaviour, depressive mood and quality of life scales were assessed by a semi-structured questionnaire. Light exposure intensity measured by Light meter (Model SDL 400). Measure for cognitive function were the Abbreviated Mental Test (AMT), Behavioral symptoms measured by the Neuropsychiatric Inventory (NPI) and mood by Geriatric Depression Scale. (GDS-15) The association of outdoor or indoor light exposure with sleep quality and quantities were analyzed by descriptive, bivariate and multivariate analyses.
Main outcome measures:
The main outcome measure was the sleep quality and quantities of patient, measured by Pittsburgh Sleep Quality Index. (PSQI)
Results:
203 subjects (60 males and 143 females) were recruited. 70.4 % of the studied subjects were females. Male to female ratio is 1:2.38. Mean age of them was 81.6 years. The mean (SD) scores of the recruited were: AMT = 4.5 (2.9); PSQI = 6.9 (3.4); NPI =14.4 (17.2); GDS-15= 4.3 (2.8); QOL-AD (patients) = 30.7 (4.9); QOL-AD (caregivers) = 29.5 (4.7) respectively. In bivariate analysis, the Global PSQI score was significantly associated with the morning and afternoon outdoor light exposure. (r = -0.634 and -0.466, respectively) For the total light exposure and mean light exposure, both of them showed strong significant negative correlation with Global PSQI score. (r = -0.769 and -0.769 respectively). Mean (SD) light exposure per day for morning and afternoon outdoor setting were 2372.9 lux (2564.7) and 1090.8 lux (1894.6) respectively. Mean(SD) light exposure per day was 1196.7 lux (866.1) Gender identity showed significant correlation with Global PSQI score (r = 0.034). Global PSQI score was significantly associated with the NPI total score (r = 0.261, p<0.001), the GDS-15 score (r = 0.336, p<0.001), the QOL-AD for patients (r = -0.257, p<0.001), and the QOL-AD for caregivers. (-0.313, p<0.001) In multivariate analyses, using general linear models, the Global PSQI score was highly independent associated with the total light exposure (p=0.000), and significantly associated with the NPI score and Gender (p = 0.011 and 0.021), after adjusting for potential confounders in bivariate analysis. (i.e. gender, activity of daily living status, hypertension and Chronic obstructive airway disease). Confounding factors were NPI and gender.
Conclusion:
In the present study, We found the intensity of natural light exposure was related to good sleep quality in older Chinese Alzheimer’s disease patients with age 65 years and above in Hong Kong as well as lesser episode of behavioural symptoms. Hence, daily outdoor light exposure is highly recommended for persons with Alzheimer’s disease.published_or_final_version
Medicine
Master
Master of Medical Sciences
39
Spavieri, Deusdedit. "Effect of temperature and light intensity on the representation of motion information in the fly's visual system." Diss., lmu, 2009. http://nbn-resolving.de/urn:nbn:de:bvb:19-99520.
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Shafia, Aminath. "Influence of pre-inoculation light intensity on development of Botrytis cinerea and Clonostachys rosea in tomato leaves." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ56366.pdf.
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Lee, Pin-Hsien, and 李品賢. "Light Intensity Measurement of Different LED Lights in Cylindrical Tank." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/6y67xr.
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碩士國立虎尾科技大學
機械與機電工程研究所
101
Photosynthetic bacteria are the most efficient producers of hydrogen, which can be cultured as carbon dioxide. In order to understand the effects of photosynthetic bacteria in different media (air, water, and a gas-liquid mixture) for hydrogen production, three kinds of light-emitting diode lights, red, white, and blue, respectively, are used to simulate light intensity in the space of cylindrical tank where photosynthetic bacteria are cultured inside. And different flow rates of air are injected to explore the LED light intensity distribution in the tank space. In this study, for the three media, the illumination and light photon flux in the aqueous medium are the highest, followed by in the gas-liquid mixture, then in the air medium. If light sources of red, white, and blue are altered sequentially, the illumination values from large to small are in the sequence of white, blue, red, respectively; in additionally, light photon fluxes from large to small are in the sequence of red, white, blue, respectively. Considering the illumination problem, red light fades situation is more different from the rest of the light fades will increase with the downward trend in the law, and does not change with the increase in wattage. In this thesis, illumination experimental results show that the values in gas-liquid mixing medium are slightly lower than in the aqueous medium, but the difference is not significant. Therefore, it is conclued that, for subsequent experiment for hydrogen production, using the gas-liquid mixed media is proper because the bubble will not cause great light fades to light and will increase the mixing effects in the cultivation container, hence, it will be beneficial for the growth of algae and to improve the efficiency of hydrogen production purposes.
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Ganesh, Kittur V. "Discomfort glare: variation of light intensity." 1986. http://hdl.handle.net/2097/22110.
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Du, Mao-feng, and 杜茂楓. "Laser direct writer with light intensity modulation." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/99858019108303321159.
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碩士國立中央大學
機械工程研究所
90
Traditionally, the diffractive optical element (ODE) is made by using the multiple binary-level lithography processes to enhance the diffractive efficiency. Due to the multiple exposures, the manufactory error will be included and more complicate processes is need to be considered. Therefore, to overcome these problems, the grey level mask can be used, in which only one exposure is needed to fabricate the optical element. This project presents that a laser machine with light intensity modulation to fabricate grey level masks. In the writer system, a solid-state laser with the power of 180 mw is used as the working light source. The processed target is laser direct write glass developed by the Canyon Material company. An acoustic-optics modulator (AOM) is used to modulate the laser intensity. To make sure the result of the processed mask, a measurement system is built. The laser direct writer system is already out of the binary methods to manufacture optical mask. The optical elements designer can use the LDW system to design any appropriate mask. Thus, the LDW system is a quite useful system for the ODEs.
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Chien, Jo-Fan, and 簡若帆. "Encoding the Light Intensity in Retina’s Firing Rate." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/ftzq3v.
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碩士國立臺灣大學
物理學研究所
105
A retina receives light stimulation and transforms the detected signal into spikes, which are then transmitted to the brain. However, how light stimulation information is conveyed by spike trains is not fully understood. Here, we utilize multi-electrode array (MEA) to record firings of the Bullfrog’s retinal ganglion cells (RGCs) under a time-varying whole field light stimulation I(t). Our goal is to understand the information shared between stimulus light intensity (I) and the firing rate (r) of RGCs. Our result shows that r will be affected by the mean intensity, Ibar, the deviation from the mean, ΔI, and the rate of change, dI/dt. To quantify the amount of information encoded by the retina, the stochastic stimulation is applied and the mutual information (MI) between I and r is calculated. We find that the MI increases as ΔI increases or I decreases, which is consistent with Weber’s law. Finally, the result from the stochastic stimulation with different correlation time shows that if the correlation time of the stimulus is longer, the retina takes shorter processing time and can even predict future stimulus.
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Chien-Chih, Lan, and 藍建智. "Cancer Cell Migration in Blue-light Intensity Gradients." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/98086648089740505395.
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碩士國立陽明大學
生醫光電研究所
103
We project different optical micro-pattern of a 473 nm blue light laser with various intensity gradients on a single lung cancer cell. We investigate the role of reactive oxygen species (ROS) in the mechanism of blue light induced cell migration behavior. A spatial light modulator (SLM) is used to generate 473 nm laser pattern imaged onto the focal plane of a microscope objective. We use a linear, a quadratic and a quartic optical intensity gradient to irradiate an individual lung cancer cell (A549). To compare with the cancer cell migration under different illumination conditions, we measure the cell displacement along X-axis direction. The A549 cell exhibited the most obvious directional migration away from the gradient of a quartic optical intensity gradient. We observed that the intracellular amounts of ROS were proportional to the intensity of the blue light, and the blue light intensity gradient could drive directional A549 cell migration. This optically induced directional A549 cell migration was inhibited by a ROS scavenger (Trolox) in the culture medium in a dose-dependent manner. In contrast, the ROS levels in fibroblasts were saturated by the blue light at low intensity and therefore the fibroblast (MRC-5) did not exhibit a directional migration in the intensity gradient pattern.
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Ku, Yi-Te, and 古義德. "Automatic Room Light Intensity Detection and Control Using a Microprocessor and Light Sensors." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/80823678697407956394.
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碩士輔仁大學
電子工程學系
97
In this paper we propose two designs using both a microprocessor and light sensors for automatic room light detection and control to save energy. The purpose of our designs is to lower the human judgment. By using the RF technology, the lights in a typical home can be controlled without wire lines. The systems are both designed to be low cost and low power consumption due to being microprocessor-based. As the first of our designs we will introduce the HLCM (Home Light Control Module) which will be installed in every light fixture of a family. The HLCM detects if a human body is present or not by using the PIR sensor circuit. If there is no human body present, all lights are turned off. If there is, the HLCM then detects the light intensity under the environment by using the light sensor circuit, and the system maintains sufficient room light by switching lights on/off. The result of using the HLCM shows that the total power consumption can be reduced. As the second design, we will introduce the FLCM (Fuzzy Light Control Module) which is similar to the first design. The FLCM detects not only if a human body enters the detection area or not but also the light intensity under the environment. The difference from the HLCM is that we use the fuzzy logic theory to design a fuzzy logic light controller to reduce energy. Using our design one can achieve high efficiency in home light power management.
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Hong, Ya-Ling, and 洪雅玲. "Effect of Light Intensity on Growth of Nannochloropsis sp." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/49672426358925984766.
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碩士大葉大學
工學院碩士在職專班
102
The effect of light intensity on the batch growth of Nannochloropsis sp.was investigated in this study. The Haldane model for growth of Nannochloropsis sp.was established for growth simulation using volumetric productivity (g/l/d) and area productivity (g/m2/d) as criterions to evaluate cultivation performance at different biomass concentrations and pond depths. The results are shown below: 1. The highest biomass concentration and specific growth rate were obtained at the light intensity of 12000 Lux. 2. The Haldane model for light intensity on growth of Nannochloropsis sp.was established. The parameter of maximum specific growth rate was estimated to be 0.53hr-1, the saturation constant was 61000 Lux and the inhibition constant was 1900 Lux. 3. Based on the simulation results, the highest volumetric productivity of Nannochloropsis sp.was obtained with the cultivation condition at the light intensity of 12000 Lux, the concentration of 1.0 g/L and the depth of 2 cm. 4. Based on the simulation results, the highest area productivity of Nannochloropsis sp.was obtained with the cultivation condition at the light intensity of 30000 Lux, the concentration of 1.0 g/L and the depth of 30 cm.
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Donelan, Matthew J. "Light intensity relations and the growth the ostrich fern /." 1995. https://scholarworks.umass.edu/theses/3450.
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Hsiao, Yao-Chung, and 蕭堯中. "Study of Goniophotometry on Relative Intensity of Light Sources." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/97677760210969659017.
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碩士國立中央大學
光電科學與工程學系
104
The relative intensity distribution curve is necessary for engineers to design optical system. Traditionally we use goniophotometer to obtain data. It works but takes much time. Much necessary space also costs too high. In such a way, users are concerned about the emergence of alternatives. With great progress both on the software and the hardware in recent years, the possibility of imaging luminance measurement device (ILMD) is getting promising. Through theory research and experiments, this study presents a systematic design includes mechanical design and algorithms to obtain relative intensity data of a LED just by one snap. To improve system stability, we have done hardware calibration (CCD noise, gray value response, image distortion and Vignetting ) for CCD and lens system to make sure only right data can be input to main algorithm. To improve the accuracy of the system, the calibration algorithm is including finding real incidence angle, BTDF, transmittance, absorption rate, solid angle normalization, and cosine law function.
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Chin, Shou-Jen, and 金守仁. "The effect of room light intensity on ocular accommodation." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/20389993422423649286.
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碩士中原大學
生物醫學工程研究所
100
Abstract The purpose of this study is to evaluate the effect of room light intensity on ocular accommodation and to assess if the effect is one of causes to worsen myopia. A total of 56 subjects (105 eyes) 21 to 27 years of age with myopia (Spherical Equivalents<-0.2 D) performed autorefraction examination to obtain refraction (defined as spherical equivalent [SE]), pupil size and near-point distance, far-point distance of vision(defined as ocular accommodation) under low, medium and high level room light intensity settings: 600, 1200 &; 1800 lux, respectively. The results show that the subjects’ ocular accommodation is better in high light intensity than that in low light intensity (p<0.01). Note that this is in the range of 2.1 D. The main difference between the high light intensity and the low light intensity is near-point distance of vision, which 1.12 cm short (p<0.01) was noted. Both myopia and pupil size were lowly positive correlated with ocular accommodation (The Pearson correlation coefficients were less than 0.14). In conclusion, high light intensity definitely facilitates the ocular accommodation. However, this may not be advantageous. When one’s ocular accommodation is better, he tends adjust it to see subjects. The consequence in the long run is that the near-point distance of vision becomes shorter and thus it likely causes myopia aggravation. These findings suggest that the use of high light intensity setting should be cautious to prevent myopia from getting worse.