Academic literature on the topic 'Varied light distribution'
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Journal articles on the topic "Varied light distribution"
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Lin, Dakui, Zhengkun Liu, Kay Dietrich, Andréy Sokolov, Mewael Giday Sertsu, Hongjun Zhou, Tonglin Huo, et al. "Soft X-ray varied-line-spacing gratings fabricated by near-field holography using an electron beam lithography-written phase mask." Journal of Synchrotron Radiation 26, no. 5 (August 16, 2019): 1782–89. http://dx.doi.org/10.1107/s1600577519008245.
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A fabrication method comprising near-field holography (NFH) with an electron beam lithography (EBL)-written phase mask was developed to fabricate soft X-ray varied-line-spacing gratings (VLSGs). An EBL-written phase mask with an area of 52 mm × 30 mm and a central line density greater than 3000 lines mm−1 was used. The introduction of the EBL-written phase mask substantially simplified the NFH optics for pattern transfer. The characterization of the groove density distribution and diffraction efficiency of the fabricated VLSGs indicates that the EBL–NFH method is feasible and promising for achieving high-accuracy groove density distributions with corresponding image properties. Vertical stray light is suppressed in the soft X-ray spectral range.
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Tlak Gajger, I., O. Vugrek, D. Grilec, and Z. Petrinec. "Prevalence and distribution of Nosema ceranae in Croatian honeybee colonies." Veterinární Medicína 55, No. 9 (October 7, 2010): 457–62. http://dx.doi.org/10.17221/2983-vetmed.
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Nosema disease of European honey bees afflicts bees worldwide. Nosema ceranae is a recently described microsporidian parasite of the honey bee (Apis mellifera) and its geographical distribution is not well known. The disease may have many negative effects on bee colonies and cause high losses for apiculture and consequently in agriculture. With this in mind, a total of 204 samples of dead bees from different localities in Croatia were selected and investigated for distribution, prevalence and diversity of N. ceranae infection, using light microscopic examination and multiplex PCR. Our results show that N. ceranae is the only nosema species found to infect honeybees in our geographically varied collection. The nucleotide sequences of amplicons from Nosema-infested honeybee samples were 100% identical with the N. ceranae sequence deposited in the GenBank database. N. ceranae infected bees were found in samples collected from each of 21 districts, and in all three climatic areas, i.e., mediterranean, mountain, and continental parts regions of Croatia.
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Capouchová, I., J. Petr, and D. Marešová. "Evaluation of size distribution of starch granules in selected wheat varieties by the Low Angle Laser Light Scattering method." Plant, Soil and Environment 49, No. 1 (December 10, 2011): 12–17. http://dx.doi.org/10.17221/4083-pse.
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The distribution of the size of wheat starch granules using the method LALLS (Low Angle Laser Light Scattering), followed by the evaluation of the effect of variety, experimental site and intensity of cultivation on the vol. % of the starch A (starch granules > 10 μm) was determined. The total starch content and crude protein content in dry matter of flour T530 in selected collection of five winter wheat varieties were determined. Vol. % of the starch A in evaluated collection of wheat varieties varied between 65.31 and 72.34%. The effect of a variety on the vol. % of starch A seemed to be more marked than the effect of site and intensity of cultivation. The highest vol. % of starch A reached evaluated varieties from the quality group C, i.e. varieties unsuitable for baking utilisation (except variety Contra with high total content of starch in dry matter of flour T530, but relatively low vol. % of starch A). A low vol. % of starch A was also found in the variety Hana (very good variety for baking utilisation). Certain variety differences followed from the evaluation of distribution of starch fractions of starch granules, forming starch A. In the case of varieties Hana, Contra and Siria higher representation of fractions up to 30 μm was recorded, while starch A in the varieties Estica andVersailleswas formed in higher degree by size fractions of starch granules over 30 μm and particularly size fraction > 50 μm was greatest in these varieties of all evaluated samples. With increasing total starch content in dry matter of flour T530 the crude protein content decreased; the vol. % of starch A not always increased proportionally with increasing total starch content.
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Cobben, M. M. P., R. van Treuren, N. P. Castañeda-Álvarez, C. K. Khoury, C. Kik, and T. J. L. van Hintum. "Robustness and accuracy of Maxent niche modelling for Lactuca species distributions in light of collecting expeditions." Plant Genetic Resources 13, no. 2 (September 18, 2014): 153–61. http://dx.doi.org/10.1017/s1479262114000847.
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Niche modelling software can be used to assess the probability of detecting a population of a plant species at a certain location. In this study, we used the distribution of the wild relatives of lettuce (Lactuca spp.) to investigate the applicability of Maxent species distribution models for collecting missions. Geographic origin data of genebank and herbarium specimens and climatic data of the origin locations were used as input. For Lactuca saligna, we varied the input data by omitting the specimens from different parts of the known distribution area to assess the robustness of the predicted distributions. Furthermore, we examined the accuracy of the modelling by comparing the predicted probabilities of population presence against recent expedition data for the endemic Lactuca georgica and the cosmopolitan Lactuca serriola. We found Maxent to be quite robust in its predictions, although its usefulness was higher for endemic taxa than for more widespread species. The exclusion of occurrence data from the perceived range margins of the species can result in important information about local adaptation to distinct climatic conditions. We discuss the potential for enhanced use of Maxent in germplasm collecting planning.
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MARTINEZ, JUANA M., HASSAN ELFARISSI, BEGONA De VELASCO, GINA H. OCHOA, ARIA M. MILLER, YING MEI CLARK, BRIAN MATSUMOTO, and LAURA J. ROBLES. "Distribution of tubulin, kinesin, and dynein in light- and dark-adapted octopus retinas." Visual Neuroscience 17, no. 1 (January 2000): 127–38. http://dx.doi.org/10.1017/s0952523800171135.
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Cephalopod retinas exhibit several responses to light and dark adaptation, including rhabdom size changes, photopigment movements, and pigment granule migration. Light- and dark-directed rearrangements of microfilament and microtubule cytoskeletal transport pathways could drive these changes. Recently, we localized actin-binding proteins in light-/dark-adapted octopus rhabdoms and suggested that actin cytoskeletal rearrangements bring about the formation and degradation of rhabdomere microvilli subsets. To determine if the microtubule cytoskeleton and associated motor proteins control the other light/dark changes, we used immunoblotting and immunocytochemical procedures to map the distribution of tubulin, kinesin, and dynein in dorsal and ventral halves of light- and dark-adapted octopus retinas. Immunoblots detected α- and β-tubulin, dynein intermediate chain, and kinesin heavy chain in extracts of whole retinas. Epifluorescence and confocal microscopy showed that the tubulin proteins were distributed throughout the retina with more immunoreactivity in retinas exposed to light. Kinesin localization was heavy in the pigment layer of light- and dark-adapted ventral retinas but was less prominent in the dorsal region. Dynein distribution also varied in dorsal and ventral retinas with more immunoreactivity in light- and dark-adapted ventral retinas and confocal microscopy emphasized the granular nature of this labeling. We suggest that light may regulate the distribution of microtubule cytoskeletal proteins in the octopus retina and that position, dorsal versus ventral, also influences the distribution of motor proteins. The microtubule cytoskeleton is most likely involved in pigment granule migration in the light and dark and with the movement of transport vesicles from the photoreceptor inner segments to the rhabdoms.
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Liu, Qiang, Longfei Xie, and Fengri Li. "The Spatial Distribution of the Needle Area of Planted Larix olgensis Trees." Forests 10, no. 1 (January 4, 2019): 28. http://dx.doi.org/10.3390/f10010028.
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The spatial distribution of leaf area largely governs both the structure and function of a tree crown. Three sample trees were selected from a 16-year-old Larix olgensis plantation in the Maoershan Forest Farm, Heilongjiang Province, based on the average diameter at breast height in each plot. All needles from the branches in the nodal and internodal pseudowhorls within the crown were destructively sampled. The crown was divided into several segments in the vertical and horizontal directions, resulting in different sub-regions. The needle area (NA) in each sub-region was computed based on the needle mass per area (NMA). The vertical and horizontal distributions and their cumulative NA distributions were characterized using the Weibull distribution function and its cumulative form. A two-dimensional NA model was created by combining the two Weibull distribution functions of the vertical and horizontal distributions. The variation in the spatial distribution of the NA among the different crown directions is discussed, and the influence of competition from competitors on the spatial distribution of NA was analyzed. The results showed that the Weibull distribution function and its cumulative form performed well in describing the vertical and horizontal distributions and the cumulative distributions of the NA, which was generally concentrated upward within the crown. This phenomenon was most apparent in dense stands with strong competition. The center of the NA exhibited an inward shift in the horizontal direction within the crown but shifted outwards with an increase in competition. The cumulative vertical and horizontal distributions of the NA obviously varied with different crown directions, which was associated mainly with the light conditions. The two-dimensional NA patterns showed that the center of the NA generally shifted outward with an increase in the relative depth into the crown (RDINC), and that more concentrated and more skewed patterns usually occurred under increased competition. Different crown directions exhibited different two-dimensional NA patterns, but the core driver was the variable light condition caused by the competitors, particularly in closed stands.
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Bretšnajdrová, Edita, Ladislav Svoboda, and Jiří Zelenka. "Determination of Particle Shape and Size Distribution of Model Types of Nanomaterials." Journal of Electrical Engineering 61, no. 5 (September 1, 2010): 302–4. http://dx.doi.org/10.2478/v10187-011-0046-z.
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Determination of Particle Shape and Size Distribution of Model Types of Nanomaterials At present, great attention is given to study of preparation and properties of various nanomaterials usable in many applications. They are utilized in varied fields of human activity - eg in electronics, medicine, paint industry etc. Besides the detailed chemical structure, such nanoparticle properties as the shape and size distribution are fundamental to the given application. To measure these parameters various methods are used, e.g. transmission electron microscopy (TEM), atomic force microscopy (AFM), acoustic spectrometry, methods based on the light scattering and X-ray disc centrifuge system.
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Zhao, Fei, Lu Song, Zhiyan Peng, Jianqin Yang, Guize Luan, Chen Chu, Jieyu Ding, Siwen Feng, Yuhang Jing, and Zhiqiang Xie. "Night-Time Light Remote Sensing Mapping: Construction and Analysis of Ethnic Minority Development Index." Remote Sensing 13, no. 11 (May 28, 2021): 2129. http://dx.doi.org/10.3390/rs13112129.
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Using toponym data, population data, and night-time light data, we visualized the development index of the Yi, Wa, Zhuang, Naxi, Hani, and Dai ethnic groups on ArcGIS as well as the distribution of 25 ethnic minorities in the study area. First, we extracted the toponym data of 25 ethnic minorities in the study area, combined with night-time light data and the population proportion data of each ethnic group, then we obtained the development index of each ethnic group in the study area. We compared the development indexes of the Yi, Wa, Zhuang, Naxi, Hani, and Dai ethnic groups with higher development indexes. The results show that the Yi nationality’s development index was the highest, reaching 28.86 (with two decimal places), and the Dai nationality’s development index was the lowest (15.22). The areas with the highest minority development index were concentrated in the core area of the minority development, and the size varied with the minority’s distance. According to the distribution of ethnic minorities, we found that the Yi ethnic group was distributed in almost the entire study area, while other ethnic minorities had obvious geographical distribution characteristics, and there were multiple ethnic minorities living together. This research is of great significance to the cultural protection of ethnic minorities, the development of ethnic minorities, and the remote sensing mapping of lights at night.
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KAŽUKAUSKAS, VAIDOTAS, and MINDAUGAS PRANAITIS. "TRAP DISTRIBUTION NEAR THE ENERGY BAND GAP EDGE IN MDMO-PPV." Functional Materials Letters 04, no. 01 (March 2011): 53–56. http://dx.doi.org/10.1142/s1793604711001567.
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Carrier transport and trapping was investigated in poly[2-methoxy-5-(3′,7′-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV) layers by thermally stimulated currents (TSC) depending on the exciting light spectral range. The upper edge of the light spectra was varied from 1.77 eV up to 3.1 eV to assure selective excitation of the defect states. We had shown that material conductivity is affected by several thermally activated processes, i.e., carrier generation from trapping states and thermally stimulated mobility growth. If the below band gap excitation was used, the effective photoconductivity activation energy values of 0.13–0.15 eV were obtained. After the above band gap excitation, the effective photoconductivity activation energy values decreased to 0.05 eV. The energy distribution of the trapping state density was shown to follow the Gaussian distribution function. The deeper states with activation energies of 0.28–0.3 eV and 0.8–0.85 eV were identified too. The results are direct indication by photo-thermo-electrical methods of distributed in energy trapping and transport states with the standard deviation of the density of states of about 0.015 eV.
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Tornés, Elisabet, and Sergi Sabater. "Variable discharge alters habitat suitability for benthic algae and cyanobacteria in a forested Mediterranean stream." Marine and Freshwater Research 61, no. 4 (2010): 441. http://dx.doi.org/10.1071/mf09095.
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Large-scale algal community patterns can be understood by studying organisation within patches. Spatial heterogeneity in light and substratum type may affect the biomass and community composition of benthic algae and cyanobacteria. We compared the effects of these factors at the species level in two reaches differing in canopy cover in a forested Mediterranean stream in winter (high water flow) and late spring (low water flow). Partial redundancy analyses revealed that the major determinants of species distribution were strongly associated with variations in measured environmental variables. Light availability, the Reynolds number and substratum type were the main factors accounting for the algal and cyanobacterial distribution. Factors affecting algal distribution varied between hydrological periods, suggesting that some species had specific requirements whereas others had a wider tolerance to environmental conditions. Our results demonstrated that the hydraulic conditions (low velocity v. high velocity) influence small-scale heterogeneity in streams, and that this affects benthic community distribution.
Dissertations / Theses on the topic "Varied light distribution"
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Mojtahedi, Mahsa. "PATCHES OF LIGHT, A LUMINAIRE WITH USER ADJUSTABLE LIGHT DISTRIBUTION." Thesis, KTH, Ljusdesign, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-297955.
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This Master’s thesis is to delineate a luminaire design which has a flexible functional form, can be controlled by the user, and which creates multidirectional light distribution within an indoor space. A lighting solution with varied light distributions can change a space’s different spatial experiences, granting a flexibility which is controlled by the user to direct light rays into walls, floors, ceilings or to create variations of these. A flexible luminaire in terms of light distribution allows, vertical and horizontal surfaces to be valued equally, because through a minimal intervention it is possible to shift the focus from one surface to another, providing a holistic interplay in space. The participants, who took part in the evaluation program of the final luminaire, freely introduced their possible activities in the predefined dining room, with different lighting proposals according to personal preferences of spatial experience. The designed luminaire was the only accessible tool to influence the space, and they managed to achieve their ideal atmospheres, and experiences, by the process of adjusting the luminaire with controlled light distribution. The varied results of the patterns of brightness and darkness on the vertical and horizontal surfaces in the predefined real space, prove the flexibility of the final design of the luminaire, MM Lamp. The luminaire fulfills the predefined design objectives of being user adjustable as well as creating varied light distribution.
Books on the topic "Varied light distribution"
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Flint, Colin, ed. The Geography of War and Peace. Oxford University Press, 2004. http://dx.doi.org/10.1093/oso/9780195162080.001.0001.
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Our world of increasing and varied conflicts is confusing and threatening to citizens of all countries, as they try to understand its causes and consequences. However, how and why war occurs, and peace is sustained, cannot be understood without realizing that those who make war and peace must negotiate a complex world political map of sovereign spaces, borders, networks of communication, access to nested geographic scales, and patterns of resource distribution. This book takes advantage of a diversity of geographic perspectives as it analyzes the political processes of war and their spatial expression. Contributors to the volume examine particular manifestations of war in light of nationalism, religion, gender identities, state ideology, border formation, genocide, spatial rhetoric, terrorism, and a variety of resource conflicts. The final section on the geography of peace covers peace movements, diplomacy, the expansion of NATO, and the geography of post-war reconstruction. Case studies of numerous conflicts include Israel and Palestine, Afghanistan, Northern Ireland, Bosnia-Herzogovina, West Africa, and the attacks of September 11, 2001.
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Van Shoelandt, Chad, and Gerald Gaus. Political and Distributive Justice. Edited by Serena Olsaretti. Oxford University Press, 2018. http://dx.doi.org/10.1093/oxfordhb/9780199645121.013.34.
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To most philosophers, unmet claims based on distributive justice imply a political injustice—some have a complaint of justice against their political system. This article explores a variety of views about how this connection may be grounded or qualified: political institutions may be one tool among others to realize an independent good, distributive principles might regulate the distributive activities of political institutions, or distributive principles might apply in light of a special relation of a political institution and its members. We also consider a view prevalent in the social contract tradition that, in light of reasonable disagreement, one cannot demand that shared political institutions conform to one’s own contentious distributive theory: members must seek terms with which all can live, even though such terms may not be anyone’s most preferred possibility.
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Clarke, Andrew. Global climate change and its ecological consequences. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780199551668.003.0016.
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The greenhouse effect is a simple consequence of an atmosphere containing gases that are transparent to visible light but which absorb infra-red radiation (radiatively active or greenhouse gases). The temperature of the lower troposphere is set by the radiation balance at the top of the atmosphere, and is determined predominantly by the CO2 concentration. Man has been adding radiatively active gases to the atmosphere since the Industrial Revolution, and this has led to an increase in the energy in the lower atmosphere, and thus a rise in its temperature. The bulk of the extra energy (~90%) has entered the ocean, which has also warmed significantly over the past century. The rate and extent of warming varies across the planet, depending on local circumstances. Palaeoecological studies have shown that changes in distribution have been a frequent response to climate change, though this requires somewhere for the organisms to move to. Many organisms have shifted their distribution in response to recent climate change. Many organisms have also shifted the timing of life-cycle events (phenology), with migration, breeding in animals, and germination, emergence, leafing and flowering in plants all occurring earlier in some (but not all) species. There are also changes in size, with some species becoming smaller as the climate warms.
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Adler, Matthew D., and Marc Fleurbaey, eds. The Oxford Handbook of Well-Being and Public Policy. Oxford University Press, 2016. http://dx.doi.org/10.1093/oxfordhb/9780199325818.001.0001.
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What are the methodologies that we should employ for designing and evaluating governmental policy, in light of the profound effects that policies have on the level and distribution of individuals’ well-being? The Oxford Handbook of Well-Being and Public Policy is a comprehensive, interdisciplinary treatment of this question—drawing from welfare economics, moral philosophy, and psychology. Part I of the Handbook covers policy-assessment methodologies, both established and emerging. Part II reviews philosophical conceptions of well-being, and the literature on “subjective well-being” in psychology and economics. The chapters in Part III focus specifically on well-being measurement, proposing or empirically illustrating various approaches to constructing a comprehensive individual-level indicator of well-being—or, alternatively, defending a “multidimensional” approach that eschews such a measure. Part IV reviews a variety of challenges for policy assessment. ThisThe Iintroductory chapter describes the Handbook structure and the role that each chapter plays therein, and highlights a number of key Handbook themes.
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Adler, Matthew D., and Marc Fleurbaey. Introduction. Edited by Matthew D. Adler and Marc Fleurbaey. Oxford University Press, 2016. http://dx.doi.org/10.1093/oxfordhb/9780199325818.013.1.
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What are the methodologies that we should employ for designing and evaluating governmental policy, in light of the profound effects that policies have on the level and distribution of individuals’ well-being? The Oxford Handbook of Well-Being and Public Policy is a comprehensive, interdisciplinary treatment of this question—drawing from welfare economics, moral philosophy, and psychology. Part I covers policy-assessment methodologies, both established and emerging. Part II reviews philosophical conceptions of well-being, and the literature on “subjective well-being” in psychology and economics. The chapters in Part III focus specifically on well-being measurement, proposing or empirically illustrating various approaches to constructing a comprehensive individual-level indicator of well-being—or, alternatively, defending a “multidimensional” approach that eschews such a measure. Part IV reviews a variety of challenges for policy assessment. This introductory chapter describes the Handbook structure and the role that each chapter plays therein and highlights a number of key Handbook themes.
Book chapters on the topic "Varied light distribution"
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Wilk, Stephen R. "Friedrich Richard Ulbricht’s Kugelphotometer." In Sandbows and Black Lights, 27–30. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780197518571.003.0006.
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With the rapid development of many new and varied sources of light in the 19th century—Argand lamps of different designs and which burned various fuels, Carcel lamps, stearin candles, paraffin candles, and spermaceti candles, electric arc lamps, Drummond lamps, incandescent lamps with various filaments, Nernst glowbars, and many others —some method was needed to compare their output. But with the sources varying in spectral content and the angular distribution of the light, how could a meaningful comparison be made? After various fruitless attempts were made to concentrate the light onto a uniform region a surprisingly simple solution was proposed.
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Gökdeniz, Ayhan. "Alternative Accommodation Businesses Within the Context of Future Jobs in the Tourism Industry." In Advances in Human Resources Management and Organizational Development, 322–45. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-5760-9.ch013.
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The rapid development of transportation and communication technologies, improvements in distribution of income, and expansion of the right to vacation to masses are growing the tourism market all over the world. The demands are diversifying and different sub-markets that address the increasingly varied understandings of vacation and accommodation are emerging in the growing tourism market. This study is the summary of the project TR/22/TRA2/0005 supported by the GMKA within the Financial Assistance Programs in 2013 and completed on February 21, 2014. Additionally, in this study, the activities carried out within the scope of the project were examined especially in terms of the webpage, tangible outputs of the project have shed some light on the future of secondary homes, and concrete suggestions were offered in terms of work to be done hereafter. This study has examined alternative accommodation businesses as a new field of work that sheds light on the future of the tourism sector. In this framework, alternative accommodation businesses (such as Airbnb, HomeAway) are discussed.
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Bueno, Juliana. "Ground-Glass Opacities." In Chest Imaging, 423–27. Oxford University Press, 2019. http://dx.doi.org/10.1093/med/9780199858064.003.0073.
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Ground-glass opacity (GGO) is defined at thin-section CT as abnormally increased lung density in which vascular and bronchial margins remain visible. This contrasts with consolidation in which those margins are obscured. In the setting of diffuse lung disease, GGO may be related to airspace filling, interstitial thickening or both. Pathologic processes manifesting as diffuse GGO have widely varied symptoms according to the etiology. The assessment of diffuse GGO is primarily achieved with HRCT. Helpful features in establishing a differential diagnosis include: chronicity, distribution of opacities and ancillary findings. Differential diagnosis of acute GGO includes infection, alveolar hemorrhage and pulmonary edema. Chronic GGO may be seen in hypersensitivity pneumonitis, organizing pneumonia, acute or chronic eosinophilic pneumonia, pulmonary alveolar proteinosis and desquamative interstitial pneumonia (DIP). GGO is a nonspecific HRCT pattern that should always be interpreted in light of acuity of symptoms, specific clinical presentation and laboratory results.
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Majcherek, Grzegorz, and Iwona Zych. "The Cretan presence in Marina el-Alamein." In Classica Orientalia. Essays presented to Wiktor Andrzej Daszewski on his 75th Birthday, 357–78. DiG Publisher, 2011. http://dx.doi.org/10.37343/pcma.uw.dig.9788371817212.pp.357-378.
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The purpose of the article is to examine the surprisingly extensive and varied evidence of Cretan finds in the archaeological record of the PCMA UW excavations at the site of the ancient Graeco-Roman harbor in Marina el-Alamein on the Mediterranean coast of Egypt and to propose an interpretation going beyond the usual and obvious, for this period and place, trade exchange. The evidence includes pottery, mainly amphorae, a numerous group of so-called Cretan or Ivy-leaf terracotta oil lamps, a tentative Cretan-sourced custom of using gold plaques with Orphic symbolism placed into the mouths of initiates in preparation for burial, as well as a female name in Doric Greek carved on one of the pillar tombs, which could have belonged to a woman of Cretan origin. The distribution of the Cretan amphora in Egypt, as reviewed by Majcherek, merits attention in the light of what it says about consumers and their individual and collective preferences. In turn, the Cretan lamps, which are otherwise not found in Egypt and the bulk of which were found as grave goods in burials, were most probably valued possessions of a specific group, a mark of cultural belonging, a memento of home, perhaps even a religious attribute. The finds from Marina el-Alamein must be considered in the context of Crete's bilateral relations with Egypt—political, cultural and commercial—and the integration of Crete in the pan-Mediterranean economic system of Roman times. The conclusion is that the assemblage in question rests well within the frame of this overall picture of mutual contacts, but one could go further and propose to view the finds as proof of tentative Cretan colony, whether mercenaries/veterans with their families or merchants and their agents.
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"Early Life History of Fishes in the San Francisco Estuary and Watershed." In Early Life History of Fishes in the San Francisco Estuary and Watershed, edited by Michael P. Marchetti, Elaine Esteban, Michael Limm, and Ryon Kurth. American Fisheries Society, 2004. http://dx.doi.org/10.47886/9781888569599.ch18.
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<em>Abstract.</em>—Light traps have been used to study the distribution and ecology of fish larvae in a variety of waters. Yet the physical and taxonomic limitations of light traps have been little studied, particularly in lotic systems. The purpose of this study was to examine aspects of light trap use, bias, and specificity in a natural stream setting. We sampled fish larvae using light traps in the upper Sacramento River watershed in April (2001, 2002) and June (2002) using five different color light sources and two trap sizes. Our results suggest that (1) small traps are as effective at sampling fish larvae as large traps, (2) color of light and/or relative intensity of light have strong effects on numbers of larvae collected, and (3) environmental factors play a role in the number of larvae collected over short time periods.
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Cronin, Thomas W., Sönke Johnsen, N. Justin Marshall, and Eric J. Warrant. "The Optical Building Blocks of Eyes." In Visual Ecology. Princeton University Press, 2014. http://dx.doi.org/10.23943/princeton/9780691151847.003.0004.
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This chapter analyzes the optical building blocks of eyes. Irrespective of their optical specializations, all eyes have one thing in common: they collect and absorb light arriving from different places in the environment, thus giving animals information about the relative distribution of light and dark in the surrounding world, including the contrasts and positions of objects. This information is used to support a variety of visual tasks, such as identifying and avoiding predators, detecting and pursuing prey or conspecifics, and orientating and navigating within the habitat. Although some animals use their eyes to perform more or less all of these tasks, others do not. All visual systems evolved within one of two main categories, being either general purpose or special purpose.
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Srivastava, Aditya, and Kalpna Katiyar. "The Ecology of Bioluminescence." In Bioluminescence [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.96636.
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Bioluminescence, or the ability to emit light biologically, has evolved multiple times across various taxa. As fascinating as the phenomenon is, various studies have been undertaken to harness this phenomenon for human use. However, the origins, distribution and ecology of bioluminescence still remain obscure. The capability to produce biological light is found in various species, ranging from tiny bacteria to huge fishes like lantern sharks. Many organisms that do not possess this ability partake in symbiotic relationships, resulting in a variety of anatomical and behavioral modifications. The ecological interactions resulting from bioluminescence are even more interesting and diverse, but many of them are still shrouded in mystery because of a lack of in-situ study. As agreed by many, bioluminescence conferred certain evolutionary advantages which still remain unclear. In spite of the lack of understanding, many spectacular ecological interactions like offence, defense, courtship or intra-specific synchrony have been observed, studied and documented, and their significance understood. As far as humans are concerned, efforts are being made to channel this capability to the best of our use, though some of these are still in their infancy. This chapter explores the origins, ecology and future prospects of bioluminescence in detail.
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Basiji, David. "Multispectral Imaging in Flow: A Technique for Advanced Cellular Studies." In Flow Cytometry for Biotechnology. Oxford University Press, 2005. http://dx.doi.org/10.1093/oso/9780195183146.003.0008.
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Flow cytometry is one of the most sophisticated technologies for the study of cellular biology, with the unique ability to analyze cell populations numbering in the millions. In addition to their great speed, flow cytometers can be configured with 10 or more detectors, so each cell can be characterized by multiple parameters corresponding to light scattered or emitted as they pass through the system. These capabilities have led to the development of a wide variety of applications for flow cytometry in cell biology, hematology, immunology, oncology, cell culture, and other fields. Nevertheless, a wide range of applications are not suited to flow cytometric analysis because the resulting data fail to capture cell morphology or the spatial distribution of signals within a cell. In contrast to conventional flow cytometry, microscopy can elucidate cell morphology by a number of means, including absorbed light imaging (brightfield), scattered light imaging (darkfield), and fluorescence imaging. An image of a typical mammalian cell measuring approximately 10 mm in diameter will cover over 300 pixels, assuming a detector resolution of 0.5mm per pixel. Hence, even a single cell image represents orders of magnitude more data than is acquired by a flow cytometric analysis of that same cell and therefore may represent far more information about that cell. In theory, a set of brightfield, darkfield, and fluorescence images of each cell would provide all the information of flow cytometry plus morphological features, such as the nuclear to cytoplasmic ratio, membrane texture, the distribution of a fluorescent probe, and so forth. However, as a practical matter, it is difficult to acquire and compare more than a few images of a cell because of the need to change fluorescence filter combinations, reconfigure the microscope for brightfield and darkfield imaging, and register the various images to compensate for shifts and distortion from the different optical arrangements. As a result, flow cytometry and microscopy have remained complementary techniques. The goal of imaging cells in flow has been elusive, despite several approaches that have achieved various levels of success over the last several decades.
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Christensen, Christian. "Images that Last? Iraq videos from YouTube to WikiLeaks." In Image Operations. Manchester University Press, 2016. http://dx.doi.org/10.7228/manchester/9781526107213.003.0009.
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On April 3, 2010, WikiLeaks and the Sunshine Press released the Collateral Murder video: a 17-minute clip showing a US Apache attack helicopter firing upon individuals in a Baghdad suburb. Amongst those killed by the 30mm cannon fire were two Reuters journalists. Rooted in the author’s earlier work on the use of YouTube by US soldiers to record everything from the criminal to the light-hearted to the banal, the chapter addresses how this clip (viewed over 15 million times on YouTube, and with myriad copies throughout the Internet) has been used and re-used for a variety of activist purposes over the past 4 years, and how it has contributed to a temporal extension of ‘the battlefield.’ Rather than a somewhat static memorialisation or transcription of war, the Collateral Murder video has been more fluid: entering and re-entering public consciousness as it is linked to news events as they unfold. This chapter discusses the flow and distribution of activist imagery as it is connected to the flow of news and current events.
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Cohen, Andrew S. "The Physical Environment of Lakes." In Paleolimnology. Oxford University Press, 2003. http://dx.doi.org/10.1093/oso/9780195133530.003.0007.
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Before discussing paleolimnological archives, we need to consider those aspects of limnology that regulate how information is produced, transmitted, and filtered through the water column. Although many limnological processes leave behind sedimentary clues of their existence or intensity and are thus amenable to paleolimnological analysis, others leave little or no detectable trace. Our consideration of limnology here emphasizes the former. Throughout the next three chapters we will examine the properties of lakes, the implications of these properties for paleolimnology, and the types of physical, chemical, and biological information that can be transcribed into sedimentary archives. Physical processes in lakes are of interest because they act as intermediary hydroclimate filters between external forcing events of interest, like climate, and the paleolimnological record. For example, understanding the hydrology of a lake is important because water inputs and outputs, which are often controlled by climate, determine lake levels, which in turn are recorded by ancient shoreline elevations, or indirectly by salinity indicators. Light and heat penetration regulate the distribution of organisms and the mixing of the water column, recorded by the distribution of various fossils, sediment types, and geochemical characteristics of sediments. Also, current and wave activity affect the transport of sedimentary particles and therefore the distribution of sediment types around a lake basin. Understanding these physical processes therefore provides us with a means of linking sedimentological, geochemical, and paleobiological records of lake deposits to the external environment. Water enters and exits lakes through a variety of paths that comprise part of the earth’s hydrological cycle. The lake components of this cycle include a series of inputs and outputs of water, which in combination with the morphometry of the lake basin, collectively determine the lake’s level. Inputs include precipitation, surface runoff from rivers, and groundwater discharge into the lake. Outflows include surface outflow, evaporation, evapotranspiration losses from emergent aquatic plants, groundwater recharge, and hydration reactions with underlying sediments. If water inputs and outputs for a lake are equal over a short time span, the lake surface elevation will remain constant. This is approximately the case in most lakes that are surficially open basins.
Conference papers on the topic "Varied light distribution"
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Sahoo, Dipankar, Benjamin R. Petersen, and Paul C. Miles. "The Impact of Swirl Ratio and Injection Pressure on Fuel-Air Mixing in a Light-Duty Diesel Engine." In ASME 2012 Internal Combustion Engine Division Spring Technical Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/ices2012-81234.
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Toluene fuel-tracer laser-induced fluorescence is employed to quantitatively measure the equivalence ratio distributions in the cylinder of a light-duty diesel engine operating in a low-temperature, high-EGR, and early-injection operating mode. Measurements are made in a non-combusting environment at crank angles capturing the mixture preparation period: from the start-of-injection through the onset of high-temperature heat release. Three horizontal planes are considered: within the clearance volume, the bowl rim region, and the lower bowl. Swirl ratio and injection pressure are varied independently, and the impact of these parameters on the mixture distribution is correlated to the heat release rate and the engine-out emissions. As the swirl ratio or injection pressure is increased, the amount of over-lean mixture in the upper central region of the combustion chamber, in the bowl rim region and above, also increases. Unexpectedly, increased injection pressure results in a greater quantity of over-rich mixture within the squish volume.
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Begdouri, Hamza, Luis Rosario, and Muhammad M. Rahman. "Fluid Flow and Heat Transfer Induced by a Window Air Conditioner Unit and Associated Thermal Comfort." In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-82825.
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This study considers airflow simulations to evaluate the impact of different window air-conditioner locations on the thermal comfort in an office rooms (OR). This paper compares the air distribution for an office room by using computational fluid dynamics (CFD) modeling. The air distribution was modeled for a typical office room window air conditioning unit, air supply from a high pressure on the top and the low pressure exhaust on the bottom considering the existing manufacturing ratios for surface areas. Calculations were done for steady-state conditions including an occupant and a light source. The discharge angle for the supply grill of the AC unit was varied from 20 to 40 degrees. The position of the air conditioner was also varied and studied at 60%, 75% and 90% of the total height of the room. In addition the location of the occupant within the office room was varied. Predictions of the air movement, room temperature, room relative humidity, comfort level, and distribution of contaminants within the office room are shown. Analysis of these simulations is discussed. The positions of the air-conditioner unit, the inlet angle and the occupant position in the office room have shown to have important impacts on air quality and thermal comfort. Results are in good agreement with available experimental data.
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Yoshioka, Y., T. Iwai, and Y. Shoukaku. "Measurement of Pressure Distribution of Shoe Sole During Walking and its Relation to Slippage." In ASME/STLE 2011 International Joint Tribology Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/ijtc2011-61238.
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Every year, many people are injured by slipping and falling accidents when walking. Clarification of the mechanism of slipping and falling may provide insight into possible solutions. The purpose of this study was to reveal the behavior of the shoe sole contact during walking by measuring both contact pressure distribution and the slippage of shoe sole blocks. A force plate with a walkway made of glass was produced to observe the contact area between the walkway and the shoe sole. The total internal reflection of light was used to distinguish the contact area and noncontact area of the shoe sole. The slippage of the shoe sole was measured by time-sequence position variations of each block. As a result, a large traction coefficient and a large slippage of the shoe sole block were found to occur immediately after the heel strike. Slippage was also detected at the period of toe off. Moreover, the maximum contact pressure of each block varied from 1.0MPa to 3.0MPa in the contact area.
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Kakadjian, Sarkis, Jarrett Kitchen, Amanda Flowers, John Vu, Amanuel Gebrekirstos, and Otman Algadi. "Successfully Optimizing Breakers in Polyacrylamides for Slickwater and High-Viscosity Fluids." In SPE Annual Technical Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/206279-ms.
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Abstract Polyacrylamide-based friction reducers (FR's) - including viscosifying polyacrylamides, which are designed to decrease proppant settling by increasing molecular weight and/or active material in the FR - are used extensively in high-rate fracture stimulations. However, because polyacrylamides are difficult to break, there have been concerns about how these materials impact fracture conductivity and formation permeability. This study presents the effect of conventional and novel oxidative breakers over the viscosity and colloidal size distribution of the broken polymers. Breakers tested include conventional persulfates, perborates and patent pending peroxides, all of which generate free radicals to degrade partially hydrolyzed polyacrylamides (PHPAs). Breakers were tested at bottomhole temperatures encountered in the Permian, Bakken, Haynesville and Eagle Ford. Changes to PHPA viscosity were determined using vibrational viscometers. Size distributions and percentage of the broken colloidal PHPA were determined by dynamic light scattering. This method can measure sizes down to 0.6 nanometers, which is within the range of even the smallest pore-throat sizes in shales. Light scattering revealed surprising anomalies in breaker performance. When aged at temperatures typical of the Permian, each of the tested breakers at each of the varied concentrations caused similar levels of viscosity reduction but different size distributions. Some breakers had the unwanted effect of narrowing the colloidal size fractions to the lower end of the spectrum. At these small sizes, colloids are more likely to overlap with segments of the pore throat distribution in some shales, which could inhibit production. In addition, when the FR was aged at the higher temperatures encountered in the Bakken, Eagle Ford and Haynesville, some breakers were not able to uniformly break the PHPA. In these cases, FR's without breakers delivered superior performance. The results clearly demonstrate that breakers may not always have the desired effect of increasing the formation's permeability. In fact, depending on the type of breaker and the concentration, they can often have detrimental effects that ultimately hinder production.
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Seitz, Sara, and Lesley M. Wright. "Thermal Characterization of a Turbulent Free Jet With Planar Laser Induced Fluorescence (PLIF)." In ASME Turbo Expo 2019: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/gt2019-92058.
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Abstract Two-color, toluene based, planar laser induced fluorescence (PLIF) is utilized to characterize the thermal structure of a turbulent, free jet. The PLIF technique has been used to measure concentration gradients for combustion applications, but its use to quantify thermal gradients is limited. To validate the method, compressed air is seeded with toluene particles. The seeded airflow is heated to temperatures varying from 300–375 K, and the heated jet exits a 1.27-cm diameter orifice into quiescent, room temperature air. The jet Reynolds number is varied from 5,000 to 15,000. As the jet exits the orifice, the toluene particles fluorescence across a 266 nm laser light sheet which ultimately provides a two-dimensional temperature distribution of the free jet. The rigorous calibration procedure for the PLIF technique is described along with the seeding nuisances needed to quantify the thermal structure of the jets. The PLIF technique has been demonstrated for this fundamental flow field, and it has proven to be applicable to more complex heat transfer and cooling applications. Furthermore, the time averaged temperature distributions obtained in this investigation can be used in the validation of turbulent CFD solvers.
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Kamplade, Jens, Tobias Mack, Andre Küsters, and Peter Walzel. "Break-Up of Threads From Laminar Open Channel Flow Influenced by Cross-Wind Gas Flow." In ASME 2014 4th Joint US-European Fluids Engineering Division Summer Meeting collocated with the ASME 2014 12th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/fedsm2014-21243.
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The breakup process of threads from laminar operating rotary atomizer (LamRot) is in the scope of this investigation. A similarity trail is used to investigate the influence of the thread deformation within a cross-wind flow on the thread breakup process. The threads emerge from laminar open channel flow while the liquid viscosity, the flow rate, the pipe inclination towards the gravity as well as the cross-wind velocity is varied. The breakup length and drop size distribution are analyzed by a back-light photography setup. The results thus obtained are compared with results of previous examination by Schröder [1] and Mescher [2]. It is found that the breakup length decreases and that the drop size grows with rising cross-wind intensity, while the width of the drop size distribution increases. At the same operating conditions, the breakup length for laminar open channel flow is smaller compared to completely filled capillaries. In contrast to this observation, the drop size distribution remains nearly unchanged. The critical velocity for the transition from axisymmetric to wind-induced thread breakup was found to be smaller than for completely filled capillaries.
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Patychuk, Bronson, and Steven N. Rogak. "Particulate Matter Emission Characterization From a Natural Gas Fuelled High Pressure Direct Injection Engine." In ASME 2012 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/icef2012-92170.
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High-Pressure Direct-Injection (HPDI) combustion of Natural Gas can reduce the gaseous and Particulate Matter (PM) emissions compared to a conventional diesel engine. Upcoming EPA and EURO emission limits may restrict particle number as well as particle mass. In preparation for these upcoming limits, the PM mass, size and composition was studied from a heavy-duty Cummins ISX engine converted to HPDI operation. To characterize the PM emissions, tests were based around a mid-speed, high-load operating point. Injection timing, equivalence ratio, gas supply pressure, EGR % and diesel injection mass were isolated and varied. PM emissions were characterized by the mobility size distribution, light scattering and filter loading. In addition a novel thermodenuder was used to determine the PM volatile fraction. It was found that EQR and EGR have the greatest effect on PM mass emissions and the correlations between these parameters are evaluated. The mean particles size and number concentrations are again most effected by EGR and EQR with smaller effects from the GRP and diesel pilot. The size distributions of the parameter variations are similar and there are no nucleation mode ultrafine particles observed. The volatile fraction is fairly constant across the parameter variations and is found to be around 18% of the mass and 11% by number of particles at this high load condition.
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Kumar, Satish, Sumanta Acharya, Roger Beuerman, and Arto Palkama. "Numerical Solution of Ocular Fluid Dynamics in a Rabbit Eye." In ASME 2003 Heat Transfer Summer Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/ht2003-47582.
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Numerical calculations of the aqueous humor dynamics in the anterior chamber of a rabbit’s eye are presented to delineate the basic flow mechanisms. The calculations are based on a geometrical model of the eye, which represents the Trabecular mesh (TM) as a multi-layered porous zone of specified pore sizes and void fraction. The outer surface of the cornea is assumed to be at a fixed temperature (corresponding to the ambient temperature), while the iris surface is assumed to be at the core body temperature. Results are obtained for both the horizontal upward-facing orientation of the eye, and the vertical orientation of the eye. Parameters varied include: the pore size in the TM to understand how TM blockage influences the flow pattern and the intra-ocular pressure (IOP) distribution; the temperature difference between the iris and the cornea to underscore the important role of buoyancy in driving the aqueous humor flow; and, the pupil size reflecting different levels of ambient light. Buoyancy is observed to be the dominant driving mechanism for the convective motion in both orientations of the eye. Reducing the TM pore size does not appear to have a significant influence on the IOP until the pore size drops below 1 micron beyond which a significant increase in IOP is observed. Variations in the pupil size appears to have little influence on the IOP or flow distributions in view of the dominant role of buoyancy in controlling the flow motion.
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Flegel, Ashlie B. "Ice Crystal Icing Investigation on a Honeywell Uncertified Research Engine in an Altitude Simulation Icing Facility." In ASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-14714.
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Abstract A Honeywell Uncertified Research Engine was exposed to various ice crystal conditions in the NASA Glenn Propulsion Systems Laboratory. Simulations using NASA’s 1D Icing Risk Analysis tool were used to determine potential inlet conditions that could lead to ice crystal accretion along the inlet of the core flowpath and into the high pressure compressor. These conditions were simulated in the facility to develop baseline conditions. Parameters were then varied to move or change accretion characteristics. Data were acquired at altitudes varying from 5 kft to 45 kft, at nominal ice particle Median Volumetric Diameters from 20 μm to 100 μm, and total water contents of 1 g/m3 to 12 g/m3. Engine and flight parameters such as fan speed, Mach number, and inlet temperature were also varied. The engine was instrumented with total temperature and pressure probes. Static pressure taps were installed at the leading edge of the fan stator, front frame hub, the shroud of the inlet guide vane, and first two rotors. Metal temperatures were acquired for the inlet guide vane and vane stators 1–2. In-situ measurements of the particle size distribution were acquired three meters upstream of the engine forward fan flange and one meter downstream of the fan in the bypass in order to study particle break-up behavior. Cameras were installed in the engine to capture ice accretions at the leading edge of the fan stator, splitter lip, and inlet guide vane. Additional measurements acquired but not discussed in this paper include: high speed pressure transducers installed at the trailing edge of the first stage rotor and light extinction probes used to acquire particle concentrations at the fan exit stator plane and at the inlet to the core and bypass. The goal of this study was to understand the key parameters of accretion, acquire particle break-up data aft of the fan, and generate a unique icing dataset for model and tool development. The work described in this paper focuses on the effect of particle break-up. It was found that there was significant particle break-up downstream of the fan in the bypass, especially with larger initial particle sizes. The metal temperatures on the inlet guide vanes and stators show a temperature increase with increasing particle size. Accretion behavior observed was very similar at the fan stator and splitter lip across all test cases. However at the inlet guide vanes, the accretion decreased with increasing particle size.
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Marinichev, Dmitrii V., Lev V. Nizovskii, Vladimir L. Nizovskii, Valerii I. Zalkind, and Yurii A. Zeigarnik. "Atomization of Superheated Water." In 2010 14th International Heat Transfer Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/ihtc14-22201.
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An experimental study of disperse composition of an air-droplet flow under atomization of water superheated relative to the saturation temperature is conducted. Atomization was accomplished with the use of centrifugal (with a nozzle diameter of 0.6 mm) and once-through jet (with a nozzle diameter of 0.3 mm) atomizers. Water pressure at the inlet to the atomizer was 4 and 8 MPa, with a temperature being varied from 20 to 270°C. The disperse composition of the atomized water was determined from a distribution of the intensity of the scattered laser beam with a wavelength of 532 nm over a wide range of the scattering angles. This technique was combined with measurements of light extinction, filming of the droplet spray, and temperature measurements in the flow to determine a degree of droplets evaporation. The experiments showed that at a water temperature of more than 170°C flashing of water discharging from the atomizers takes place, due to which considerably finer atomization of water is obtained as compared to that with the use of mechanical and pneumatic atomizers. At a temperature of injected water of 220–240°C, 70% of droplets (by mass) have a value of d32 diameter of 0.2 to 3 μm. While atomizing superheated water, the size distribution of droplets, has a bimodal pattern, i.e., along with the existence of fine droplets, certain amount of droplets of 6–15 μm in diameter (up to 30%) is retained in the flow. When atomizing superheated water, centrifugal and jet atomizers provide approximately the same distribution of droplet sizes. This attests that flashing plays the determining role in the atomization process. Saturation of water to be atomized by air or carbon dioxide does not noticeably change disperse composition of the air-droplet mixture, while atomizing water at a temperature of more than 170°C. Due to the impact of the air flow, fine droplets form a spatially localized spray extended along the flow with a semi-angle of expansion of 10–12 deg. This fact should be accounted for while arranging water injection systems. The fine atomization achieved significantly increases a rate of droplet evaporation in the carrying flow, prevents their deposition on the articles of equipment, and provides more efficient cooling of the working medium.
Reports on the topic "Varied light distribution"
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Asenath-Smith, Emily, Emma Ambrogi, Lee Moores, Stephen Newman, and Jonathon Brame. Leveraging chemical actinometry and optical radiometry to reduce uncertainty in photochemical research. Engineer Research and Development Center (U.S.), September 2021. http://dx.doi.org/10.21079/11681/42080.
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Subtle aspects of illumination sources and their characterization methods can introduce significant uncertainty into the data gathered from light-activated experiments, limiting their reproducibility and technology transition. Degradation kinetics of methyl orange (MO) and carbamazepine (CM) under illumination with TiO₂ were used as a case study for investigating the role of incident photon flux on photocatalytic degradation rates. Valerophenone and ferrioxalate actinometry were paired with optical radiometry in three different illumination systems: xenon arc (XE), tungsten halogen (W-H), and UV fluorescent (UV-F). Degradation rate constants for MO and CM varied similarly among the three light systems as k W-H < kiv-F < kXE, implying the same relative photon flux emission by each light. However, the apparent relative photon flux emitted by the different lights varied depending on the light characterization method. This discrepancy is shown to be caused by the spectral distribution present in light emission profiles, as well as absorption behavior of chemical actinometers and optical sensors. Data and calculations for the determination of photon flux from chemical and calibrated optical light characterization is presented, allowing us to interpret photo-degradation rate constants as a function of incident photon flux. This approach enabled the derivation of a calibrated ‘rate-flux’ metric for evaluating and translating data from photocatalysis studies.