Tesis sobre el tema "High altitude"
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Brown, K. D. y Trevor Sorensen. "HIGH ALTITUDE TRANSMITTER FLIGHT TESTING". International Foundation for Telemetering, 2004. http://hdl.handle.net/10150/605062.
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International Telemetering Conference Proceedings / October 18-21, 2004 / Town & Country Resort, San Diego, CaliforniaThis paper describes a high altitude experimental flight test platform developed by the University of Kansas (KU) and the National Nuclear Security Administration’s Kansas City Plant (NNSA’s Kansas City Plant) for high altitude payload flight testing. This platform is called the Kansas University Balloon Experiment Satellite (KUBESat). The paper describes the flight test platform and experimental flight test results captured at Fort Riley, KS from characterization of the KCP developed Distributed Transmitter (DTX).
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Hansen, Christel Dorothee. "On high-altitude and high- latitude frost environments". Thesis, Rhodes University, 2018. http://hdl.handle.net/10962/62383.
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Frost environments occur throughout the world, with associated processes occurring across climatic zones. Climatic geomorphology proposes that climatic zones, largely derived from annual average air temperature and precipitation values, have specific landforms and processes active within that zone. This study offers unique insights into the frost environments of three locations in the Southern Hemisphere, namely the Eastern Cape Drakensberg of South Africa, sub-Antarctic Marion Island, and Dronning Maud Land of Antarctica. The Drakensberg ranges from temperate to alpine, Marion Island is hyper-maritime, and Dronning Maud Land a polar desert. Drivers and forcings on the ground frost regime are identified, as are future climatic scenarios. Altitude and latitude were identified as the most important locational drivers, while air temperature showed highest correlation with freezing events. The initiation of a freeze event correlated strongly with maximum ground temperatures. Vegetation cover was found to ameliorate frost cycles, thereby increasing ground temperatures. Dronning Maud Land of Antarctica is characterised by annual frost (permafrost), with limited seasonal thaw in summer. Thawing cycles reflected the depth of the active layer, which ranged from just under 60 cm for Robertskollen (at lowest altitude) to less than 15 cm on Slettfjell (at greatest altitude). Marion Island had the most active frost environment, exhibiting both seasonal frost, and ubiquitous shallow diurnal frost cycles. The Drakensberg were largely frost-free, with limited seasonal frost and few diurnal freeze- thaw events. Diurnal frost processes were found to be azonal, and present at all three study locations. Evidence of landforms derived from diurnal frost processes were evident in each zone. Equifinality/convergence of form was present to a degree. The presence of patterned ground, which was not wholly derived from frost processes, suggests a measure of equifinality. Furthermore, openwork block deposits, of which not all are either blockstreams nor blockfields, are not necessarily the result of frost processes. The periglacial environment is poorly defined and methods to delineate this environment, as well as other climatic zones, should include additional parameters. Delineating zones on annual (and limited) monthly averages based on predominantly temperature, is not sufficient. While concepts of climatic geomorphology may be applied in a general sense, this framework is not suited to working at smaller scales. Specifically, periglacial environments should be delineated using ground moisture, as well as air temperature. Furthermore, vegetation and snow cover are important, as are soil textural properties.
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Williams, David Reid. "The pulmonary circulation at high altitude". Thesis, University of Liverpool, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316610.
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Johnson, Pamela Lesley. "Sleep and Breathing at High Altitude". University of Sydney, 2008. http://hdl.handle.net/2123/3531.
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Doctor of Philosphy (PhD)This thesis describes the work carried out during four treks, each over 10-11 days, from 1400m to 5000m in the Nepal Himalaya and further work performed during several two-night sojourns at the Barcroft Laboratory at 3800m on White Mountain in California, USA. Nineteen volunteers were studied during the treks in Nepal and seven volunteers were studied at White Mountain. All subjects were normal, healthy individuals who had not travelled to altitudes higher than 1000m in the previous twelve months. The aims of this research were to examine the effects on sleep, and the ventilatory patterns during sleep, of incremental increases in altitude by employing portable polysomnography to measure and record physiological signals. A further aim of this research was to examine the relationship between the ventilatory responses to hypoxia and hypercapnia, measured at sea level, and the development of periodic breathing during sleep at high altitude. In the final part of this thesis the possibility of preventing and treating Acute Mountain Sickness with non-invasive positive pressure ventilation while sleeping at high altitude was tested. Chapter 1 describes the background information on sleep, and breathing during sleep, at high altitudes. Most of these studies were performed in hypobaric chambers to simulate various high altitudes. One study measured sleep at high altitude after trekking, but there are no studies which systematically measure sleep and breathing throughout the whole trek. Breathing during sleep at high altitude and the physiological elements of the control of breathing (under normal/sea level conditions and under the hypobaric, hypoxic conditions present at high altitude) are described in this Chapter. The occurrence of Acute Mountain Sickness (AMS) in subjects who travel form near sea level to altitudes above 3000m is common but its pathophysiology not well understood. The background research into AMS and its treatment and prevention are also covered in Chapter 1. Chapter 2 describes the equipment and methods used in this research, including the polysomnographic equipment used to record sleep and breathing at sea level and the high altitude locations, the portable blood gas analyser used in Nepal and the equipment and methodology used to measure each individual’s ventilatory response to hypoxia and hypercapnia at sea level before ascent to the high altitude locations. Chapter 3 reports the findings on the changes to sleep at high altitude, with particular focus on changes in the amounts of total sleep, the duration of each sleep stage and its percentage of total sleep, and the number and causes of arousals from sleep that occurred during sleep at increasing altitudes. The lightest stage of sleep, Stage 1 non-rapid eye movement (NREM) sleep, was increased, as expected with increases in altitude, while the deeper stages of sleep (Stages 3 and 4 NREM sleep, also called slow wave sleep), were decreased. The increase in Stage 1 NREM in this research is in agreement with all previous findings. However, slow wave sleep, although decreased, was present in most of our subjects at all altitudes in Nepal; this finding is in contrast to most previous work, which has found a very marked reduction, even absence, of slow wave sleep at high altitude. Surprisingly, unlike experimental animal studies of chronic hypoxia, REM sleep was well maintained at all altitudes. Stage 2 NREM and REM sleep, total sleep time, sleep efficiency and spontaneous arousals were maintained at near sea level values. The total arousal index was increased with increasing altitude and this was due to the increasing severity of periodic breathing as altitude increased. An interesting finding of this research was that fewer than half the periodic breathing apneas and hypopneas resulted in arousal from sleep. There was a minor degree of upper airway obstruction in some subjects at sea level but this was almost resolved by 3500m. Chapter 4 reports the findings on the effects on breathing during sleep of the progressive increase of altitude, in particular the occurrence of periodic breathing. This Chapter also reports the results of changes to arterial blood gases as subjects ascended to higher altitudes. As expected, arterial blood gases were markedly altered at even the lowest altitude in Nepal (1400m) and this change became more pronounced at each new, higher altitude. Most subjects developed periodic breathing at high altitude but there was a wide variability between subjects as well as variability in the degree of periodic breathing that individual subjects developed at different altitudes. Some subjects developed periodic breathing at even the lowest altitude and this increased with increasing altitude; other subjects developed periodic breathing at one or two altitudes, while four subjects did not develop periodic breathing at any altitude. Ventilatory responses to hypoxia and hypercapnia, measured at sea level before departure to high altitude, was not significantly related to the development of periodic breathing when the group was analysed as a whole. However, when the subjects were grouped according to the steepness of their ventilatory response slopes, there was a pattern of higher amounts of periodic breathing in subjects with steeper ventilatory responses. Chapter 5 reports the findings of an experimental study carried out in the University of California, San Diego, Barcroft Laboratory on White Mountain in California. Seven subjects drove from sea level to 3800m in one day and stayed at this altitude for two nights. On one of the nights the subjects slept using a non-invasive positive pressure device via a face mask and this was found to significantly improve the sleeping oxyhemoglobin saturation. The use of the device was also found to eliminate the symptoms of Acute Mountain Sickness, as measured by the Lake Louise scoring system. This finding appears to confirm the hypothesis that lower oxygen saturation, particularly during sleep, is strongly correlated to the development of Acute Mountain Sickness and may represent a new treatment and prevention strategy for this very common high altitude disorder.
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White, Ryan D. "A high-altitude nuclear environment simulation". Thesis, Manhattan, Kan. : Kansas State University, 2009. http://hdl.handle.net/2097/2315.
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Croft, Quentin. "Human responses to simulated high altitude". Thesis, University of Oxford, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.711614.
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York, Julia McRae. "Respiratory mechanics of high altitude waterfowl". Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/58744.
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Birds living at high altitude (>3,000 meters) are not only able to cope with reduced oxygen availability due to hypobaria, but they are also able to achieve one of the most metabolically costly form of locomotion at these altitudes: flight. To perform such a metabolically demanding activity, in addition to energetically expensive daily tasks such as foraging, predator escape, and reproduction, all in oxygen limited (hypoxic) conditions, means that high altitude birds must enhance oxygen supply to maintain oxygen homeostasis. The primary means of increasing oxygen supply is increasing ventilation of the respiratory gas exchange surface. However, the metabolic cost of ventilation is unknown for birds at rest, as is whether this cost varies among bird species. In this thesis, the cost and work of breathing are compared in fourteen avian species to determine whether variation in the work of breathing is due to mechanical or morphological changes in the respiratory system, and if any observed changes are associated with living at high altitude. High altitude birds tended to have large and compliant respiratory systems compared with low altitude taxa, which reduces the work of breathing. However, the evidence also suggests that respiratory morphology and mechanics in birds may be more constrained by life history strategy than by evolutionary time at altitude, although species in this study that have no high altitude sister taxa (their lineages have never radiated to high altitude) struggled the most with increasing oxygen supply. Finally, birds at rest were estimated to have a lower cost of breathing than mammals, contrary to the hypothesis that cost of breathing would be high in birds due to the heavy flight muscles weighing down the sternum.Science, Faculty of
Zoology, Department of
Graduate
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De, Frey Willem Hendrik. "Phytosociology of the Mpumalanga high altitude grasslands". Diss., University of Pretoria, 1999. http://hdl.handle.net/2263/23808.
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A phytosociological study covering approximately 12 000 km2 was completed within Southeastern Mpumalanga high altitude grasslands. The towns of Belfast, Barberton, Piet Retief and Wakkerstroom represented the four corners of the area. The study formed part of the Grassland Biome Project sponsored by the Department of Environmental Affairs and Tourism. The Braun-Blanquet approach was applied. Grassland research results from the western side of the country, determined that soil patterns and vegetation distribution are significantly correlated. Based on these results, it was hypothesised that the same correlation would exist in the east. The eight soil patterns used during the survey as homogenous units, were Ab, Ac, Ad, Ae, Ea, Fa, Fb and lb. A pro rata, randomly stratified sample size of 405 plots were used. An in-depth literature study of the environmental and other factors related to vegetation distribution, indicated on local scale that a significant correlation exists between landform and plant distribution. Two geographic information systems, Idrisi and Arc-Info/Niew, aided in the modelling and extraction of environmental attributes from existing databases. A TWINSPAN classification of the complete floristic data set falsified the null hypothesis based on the soil patterns but verified the null hypothesis based on landforms. The TWINSPAN dendrogram revealed clusters associated with three landforms (mountains, hills and lowlands, and plains) in two ecosystems, the terrestrial and the wetlands or aquatic. The three landforms represented three mapping units: Southeastern Mpumalanga Mountain Vegetation Type, Southeastern Mpumalanga Hills and Lowland Vegetation Type and Southeastern Mpumalanga Plain Vegetation Type. A second TWINSPAN classification was executed on each of the vegetation types. The resulting clusters were tested for uniqueness and informational value using a set of criteria. Those clusters which qualified were arranged in a Braun-Blanquet table to determine communities, sub-communities and variations using constancy and fidelity values. The plant communities within the vegetation types were described in terms of floristic composition and environmental attributes. The indirect gradient analysis ordination program DECORANA was used to determine environmental trends and was confirmed by using multiple regression. Soil water availability was the most significant environmental trend between the two ecosystems and within the communities of the ecosystems in each vegetation type. Soil water availability is influenced by numerous factors, whose significance differs from one vegetation type to another. lt was concluded from this study that, in high rainfall areas, soil patterns and vegetation distribution are not significantly correlated but that landforms and vegetation distribution are significantly correlated. Landscape slope configuration or landform influences soil water availability through soil characteristics (rockiness, texture and depth) and local climatic conditions (aspect, perpendicular insolation and precipitation). lt is suggested that the current Grassland - Savanna Biome boundary be changed towards the west using the boundary between the covered and exposed shields. This suggestion is supported by the presence of Hyparrhenia hirta/Hyperthelia dissoluta - Acacia sieberiana communities to the east of the study area in the different vegetation types which correlate significantly with the thorntree-tall grass savanna formation on a global scale. AFRIKAANS : 'n Fitososiologiese studie is gedoen van die Suid-oostelike Mpumalanga hoe liggende grasveld tussen die dorpe Belfast, Barberton, Piet Retief en Wakkerstroom. 'n Area van ongeveer 12 000 km2 is bestudeer. Die studie is deel van die Grasveld Bioom Projek gefinansier deur die Departement van Omgewingsake en Toerisme. Die Braun-Blanquet benadering is gebruik. Resultate van grasveldnavorsing in die westelike deel van die grasveld bioom, het aangedui dat 'n betekenisvolle verband tussen grondpatrone en plantegroei verspreiding bestaan. Na aanleiding van hierdie resultate, is die hipotese gemaak dat dieselfde verband in die ooste sal voorkom. Agt grondpatrone, Ab, Ac, Ad, Ae, Fa, Fb, en lb is as homogene eenhede beskou. 'n Eweredige ewekansige steekproefneming van 405 punte is gebruik. 'n Deeglike literatuurstudie van die omgewing en faktore wat verband hou met plantegroei verspreiding, het aangedui op lokale skale, dat 'n verband tussen landvorm en plantegroei verspreiding bestaan. Twee geografiese inligtingstelsels, ldrisi en Arc-lnfo/View, is gebruik in die modelering en verkryging van omgewings data vanuit bestaande databasisse. 'n TWINSPAN klassifikasie gebaseer op die volledige spesiesamestelling, het die nul hipotese oor die grondpatrone ongeldig verklaar maar die nul hipotese oor die landvorme bevestig. Die TWINSPAN dendrogram het groeperings bevat wat verband hou met drie landvorme (berge, heuwels en laaglande en vlaktes) in twee ekosisteme, terrestrieel en vleiland van akwatiese omgewings. Die drie landvorme is beskou as drie karteerbare eenhede: Suid-oostelike Mpumalanga Berg Plantegroeitipe, Suidoostelike Mpumalanga Heuwels en Laagland Plantegroeitipe en Suid-oostelike Mpumalanga Vlakte Plantegroeitipe. 'n Tweede TWINSPAN klassifikasie is op elk van die plantegroeitipes toegepas. Elke plantegroeitipe se groeperings is met behulp van bepaalde voorwaardes vir uniekheid en inligtingswaarde getoets. Die groeperings wat gekwalifiseer het, is met behulp van konstantheids en getrouheids waardes in 'n Braun-Blanquet tabel gerangskik in gemeenskappe, sub-gemeenskappe en variasies. Elke plantegroei tipe se gemeenskappe is beskryf in terme van floristies spesiesamestelling en omgewingsfaktore. 'n indirekte gradientanalise ordeningsprogram DECORANA is gebruik vir die bepaling van omgewings tendense en is bevestig met behulp van veelvuldige regressies. Grondwaterbeskikbaarheid was die mees betekenisvolle omgewingstendens tussen die ekosisteme en die gemeenskappe van die plantegroei tipes. Grondwaterbeskikbaarheid word deur 'n aantal faktore beïnvloed, waarvan die belangrikheid van plantegroei tipe tot plantegroeitipe wissel. 'n Gevolgtrekking van die studie is, dat in hoë reënvalomgewings daar nie 'n betekenisvolle verband is tussen grondpatrone en plantegroei verspreiding nie maar wel tussen landvorme en plantegroeiverspreiding. Landskap hellingsamestelling of landvorme beïnvloed grondwaterbeskikbaarheid deur middel van grondeienskappe (klipperigheid, tekstuur en diepte) en lokale klimaatstoestande (aspek, loodregte bestraling en presipitasie). Daar word voorgestel dat die huidige Grasveld- Savanna Bioom grens weswaarts geskuif word om ooreen te stem met die grens tussen die bedekte en blootgestelde plate. Die voorstel word ondersteun deur die teenwoordigheid van Hyparrhenia hirta/Hyperthelia dissoluta - Acacia sieberana plantgemeenskappe in die ooste van die plantegroeitipes wat betekenisvol ooreenstem met die langgras-doring boom savanna formasie op globale skaal.Dissertation (MSc)--University of Pretoria, 1999.
Plant Science
unrestricted
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Wood, Curtis Ron. "The biometeorology of high-altitude insect layers". Thesis, University of Reading, 2007. http://centaur.reading.ac.uk/852/.
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Flight at high altitude is part of a migration strategy that maximises insect population displacement. This thesis represents the first substantial analysis of insect migration and layering in Europe. Vertical-looking entomological radar has revealed specific characteristics of high-altitude flight: in particular layering (where a large proportion of the migrating insects are concentrated in a narrow altitude band). The meteorological mechanisms underpinning the formation of these layers are the focus of this thesis. Aerial netting samples and radar data revealed four distinct periods of high-altitude insect migration: dawn, daytime, dusk, and night-time. The most frequently observed nocturnal profiles during the summertime were layers. It is hypothesised that nocturnal layers initiate at a critical altitude (200–500 m above ground level) and time (20:00–22:00 hours UTC). Case study analysis, statistical analysis, and a Lagrangian trajectory model showed that nocturnal insect layers probably result from the insects’ response to meteorological conditions. Temperature was the variable most correlated with nocturnal insect layer presence and intensity because insects are poikilothermic, and temperatures experienced during high-altitude migration in temperate climates are expected to be marginal for many insects’ flight. Hierarchical effects were detected such that other variables—specifically wind speed—were only correlated with insect layer presence and intensity once temperatures were warm. The trajectory model developed comprised: (i) insect flight characteristics; (ii) turbulent winds (which cause vertical spread of the layer); and (iii) mean wind speed, which normally leads to horizontal displacements of hundreds of kilometres in a single migratory flight. This thesis has revealed that there is considerable migratory activity over the UK in the summer months, and a range of fascinating phenomena can be observed (including layers). The UK has moved from one of the least studied to perhaps the best studied environments of aerial insect migration and layering in the world.
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Zapfe, Bettina Dorothee. "Millimetre wave propagation from high-altitude platforms". Thesis, University of Bath, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.275452.
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Lim, Woo Lip. "Handover for high altitude platform station UMTS". Thesis, University of Surrey, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.250939.
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Katzis, Konstantinos. "Resource allocation techniques for high altitude platforms". Thesis, University of York, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.424529.
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Chen, Guanhua. "Capacity enhancement using multiple high altitude platforms". Thesis, University of York, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.434000.
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Deng, Yu. "Coded polarization multiplexing for high-altitude platforms". Thesis, University of York, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.444290.
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Windsor, Jeremy S. "Electrocardiographic changes in the high altitude environment". Thesis, University of Sheffield, 2015. http://etheses.whiterose.ac.uk/19877/.
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Objective: This thesis sets out to identify the rate, rhythm and morphological changes that occur in the ECG’s of healthy lowland residents who are exposed to hypoxic conditions at sea level and high altitude. Methods: Three separate ECG studies were performed on healthy lowland residents. The first was conducted on 16 members of the Caudwell Xtreme Everest Expedition (CXE) during a stay at Mt Everest Base Camp (EBC) (5300m). The second was conducted on 37 members of the Team Everest Expedition (TE) during an ascent to EBC. Finally, a group of 10 participants were studied whilst breathing a range of hypoxic gas mixtures (12-18% oxygen) at sea level (AHS). Results: Rate - CXE - The median resting heart rate increased following ascent to Mt Everest Base Camp (EBC) (5300m) (P < 0.05). TE - The mean resting heart rate of male and female participants increased following ascent to Namche Bazaar (3500m) (P < 0.05). Rhythm – CXE, TE and AHS: No significant difference was observed in the incidence of atrial or ventricular ectopics following ascent to Mt Everest Base Camp (5300m). Morphology – CXE: The sum of P wave amplitudes in II, III and aVF increased at EBC (P < 0.05). The T wave amplitude in V1 decreased at EBC (P < 0.05). QTc (Bazett’s and Fridericia’s) increased on arrival at EBC (P < 0.05). TE: QTc (Bazett’s and Fridericia’s) increased on ascent to high altitude. QTc (Bazett’s) increased following ascent from Namche Bazaar (3500m) to Gorak Shep (5200m) (P < 0.05). AHS: QTc (Bazett’s and Fridericia’s) increased in hypoxia (P < 0.05). Conclusion: Significant changes in rate, rhythm and morphology occur in healthy lowland residents who are exposed to hypoxic conditions.
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Eastham, Sebastian D. (Sebastian David). "Human health impacts of high altitude emissions". Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/98585.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2015.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 132-159).
Millions of deaths worldwide are attributed annually to exposure degraded surface air quality and UV-induced skin cancer. However, the focus has been on surface emissions, and the contribution of high altitude emissions to these issues is rarely examined. In this thesis, potential links are investigated between high altitude emissions and damages or benefits to human health via photochemical effects. Changes in population exposure to fine particulate matter, ozone and UV-B radiation resulting from current and future high altitude emissions are calculated, applying epidemiologically-derived impact functions to estimate resultant mortality and morbidity. A stratospheric extension is developed for the widely-used tropospheric model GEOS-Chem, which has been shown to accurately model tropospheric conditions and used in simulations of remote and urban pollution. This extended model, the GEOS-Chem UCX, can propagate a stratospheric perturbation through to a tropospheric impact, including shortwave UV fluxes, long-lived species, stratospheric water chemistry and high altitude aerosols. This model is employed to estimate the impacts of reversing 1 K of global warming using stratospheric sulfate aerosol injection. In total, it is projected that 85,000 additional premature mortalities would occur in 2040 due to particulate matter exposure, but that reduced ozone loading would prevent 64,000 mortalities worldwide. Aerosol injection also results in a 5.7% reduction in the global ozone column and a 3.0% increase in surface UV-B, which could cause 3,700 additional melanoma mortalities per year. By comparison, surface air quality and UV-B impacts due to aviation emissions are found to have resulted in 16,000 premature mortalities globally in 2006, of which 450 occurred in North America. Ozone exposure contributes 43% of this total. The increase in tropospheric ozone due to aviation emissions is found to have prevented 390 skin cancer mortalities in 2006. This thesis quantifies the photochemical mechanisms connecting future and proposed high altitude emissions schemes to human health impacts and provides an estimate of mortality and morbidity attributable to aviation and sulfate aerosol injection.
by Sebastian D. Eastham.
Ph. D.
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Tang, Yunmo. "The current situation of high-altitude wind power". Thesis, Högskolan i Gävle, Avdelningen för bygg- energi- och miljöteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-14734.
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The importance of the use of renewable energy sources is obviously. But what the problem confused us, is that renewable energy unlike the fossil fuel have such high energy density which means the renewable generally was dispersed form. In other words, in order to obtain amount of the energy we need, require to exploitation a wider cover area. Therefore, scientists and companies are struggling to find high densely renewable energy as possible, which is high altitude wind energy, have very promising but not developed so much by humans. High altitude wind power is indicating the altitude between 3000 meters and 10000 meters. So far, high altitude wind power is a new renewable energy that basically not development or utilization yet, but which is an abundant reserves. High altitude wind power is a widely distributed renewable clean energy. The characterized of high-altitude wind energy is fast speed, wide distribution, high stability and perennial. Utilize high-altitude wind power can get high stability with low cost of wind power generation, which is one of the notable features for high-altitude wind power, but also is one of the most significant advantages for high-altitude wind energy compared to conventional wind energy. High altitude wind power generation equipment is more compact and flexible, far superior then the traditional fan, which equip with thick blades and the tower must be fixed in the depths of the ocean or in the ground.To development renewable power in a large scale, to face the global climate change, achieve the sustainable development become the inevitable for human development. How to solve the energy shortage problem has become an important question, harness high altitude wind power was becomes the focus of multinational technology.
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Martin, D. S. "Human adaptation to hypobaric hypoxia at high altitude". Thesis, University College London (University of London), 2013. http://discovery.ucl.ac.uk/1383226/.
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As humans ascend to high altitude, the resulting hypobaric hypoxia necessitates adaptation in order continue functioning. Whilst much is known about changes that facilitate a restoration of systemic oxygen delivery during ascent, less is know about alterations in the peripheral microcirculation and how these affect acclimatisation and performance at altitude. The limit of human adaptation to hypoxia is also undefined. Using data derived from a number of studies conducted on healthy volunteers at high altitude, this thesis explores changes in skeletal muscle oxygenation and sublingual microcirculatory blood flow, and how these may relate to the process of acclimatisation. In addition, exercise was used to perturbate the relationship between oxygen delivery and utilisation at altitude, and experiments at extreme altitude sought to define the limits of human tolerance to hypoxia. Data relating to four subjects resting just below the summit of Mount Everest (at 8400m), demonstrated a degree of systemic hypoxia never before reported in humans. Given sufficient time, arterial oxygen content remained steady during ascent to 7100m. Sublingual microcirculatory blood flow declined at altitude, whilst the density of blood vessels increased. At altitude, absolute skeletal muscle oxygenation declined; the response to a brief ischaemic episode was a reduction in rate of subsequent muscle reoxygenation; and the rate of muscle desaturation during exercise increased. Systemic oxygen extraction during exercise at altitude remained unchanged from that observed at sea level. These results support the hypothesis that a significant barrier to oxygen flux exists within tissues that is heightened at altitude. Restoration of convective oxygen delivery does little to improve tissue oxygenation, and adaptations within the microcirculation may differentiate phenotypic responses observed on prolonged exposure to hypoxia. Graded ascent to altitude by healthy volunteers provides valid data that may herald further research in the clinical arena, bringing about improved outcome in critically ill patients.
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Frisk, Ulrika. "Effects of high-altitude trekking on body composition". Thesis, Mittuniversitetet, Avdelningen för hälsovetenskap, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-22219.
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Sojourns at high altitude are often accompanied by weight loss and changes in body composition. The aim was to study body composition before and after 40 days high-altitude exposure. The subjects were four women and six men, non-smoking, healthy and active students and a scientist from Mid Sweden University in Östersund with a mean (SD) age of 26 (10) years. All subjects volunteered for a six-week trek to the Mount Everest Base Camp via Rolwaling in Nepal. Before the sojourn subject’s height was 177 (10) cm and weight was 71.9 (10) kg. Body composition was measured with Lunar iDXA at the Swedish Winter Sports Research Centre in Östersund before and after the trek. Total body mass (SD) decreased from 71.8 (10.0) kg before to 69.7 (9.4) kg after the trek (P=0.00). Total fat mass decreased from 14.7 (5.9) kg to 13.8 (4.6) kg (P=0.01). Fat percent decreased from 21.6 (7.9) % to 21.0 (7.2) % (P=0.03). Total lean mass decreased from 54.0 (10.0) kg to 52.9 (9.7) kg (P=0.01). Bone mineral content was unchanged, 3.04 (0.5) kg before and 3.03 (0.5) after (P=0.13). Thus both total body mass and total lean mass had decreased after a six week trekking in Nepal.
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Cook, Eric C. "Broad area wireless networking via high altitude platforms". Monterey, California: Naval Postgraduate School, 2013. http://hdl.handle.net/10945/34648.
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Approved for public release; distribution is unlimitedThis thesis explores a novel network design concept to address the data and communications needs of the Department of Defense (DoD). Current and future military operations are increasingly reliant upon data connectivity to facilitate situational awareness and distribute vital information. Current infrastructures are insufficient to meet the growing demand, especially in the myriad austere environments where military forces operate. The DoD has become reliant upon increasingly vulnerable and expensive satellite communications to fill those gaps. The wireless data technologies utilized in the commercial sector to meet the data distribution requirements of business and commercial telecommunications providers can be leveraged and adapted to meet the connectivity requirements of the DoD. By pairing these technologies with developing HAPs and their capabilities the potential for a long-range wireless broadband solution emerges. This thesis evaluates broadband wireless data technologies in combination with High Altitude Platform (HAP) technologies. It proposes a network design concept to serve as a model for future research and the ultimate integration of HAPs into battlefield information architecturesbringing the concepts of network centric warfare ever closer to reality.
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Furey, Allister David John. "Evolutionary robotics in high altitude wind energy applications". Thesis, University of Sussex, 2012. http://sro.sussex.ac.uk/id/eprint/7667/.
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Recent years have seen the development of wind energy conversion systems that can exploit the superior wind resource that exists at altitudes above current wind turbine technology. One class of these systems incorporates a flying wing tethered to the ground which drives a winch at ground level. The wings often resemble sports kites, being composed of a combination of fabric and stiffening elements. Such wings are subject to load dependent deformation which makes them particularly difficult to model and control. Here we apply the techniques of evolutionary robotics i.e. evolution of neural network controllers using genetic algorithms, to the task of controlling a steerable kite. We introduce a multibody kite simulation that is used in an evolutionary process in which the kite is subject to deformation. We demonstrate how discrete time recurrent neural networks that are evolved to maximise line tension fly the kite in repeated looping trajectories similar to those seen using other methods. We show that these controllers are robust to limited environmental variation but show poor generalisation and occasional failure even after extended evolution. We show that continuous time recurrent neural networks (CTRNNs) can be evolved that are capable of flying appropriate repeated trajectories even when the length of the flying lines are changing. We also show that CTRNNs can be evolved that stabilise kites with a wide range of physical attributes at a given position in the sky, and systematically add noise to the simulated task in order to maximise the transferability of the behaviour to a real world system. We demonstrate how the difficulty of the task must be increased during the evolutionary process to deal with this extreme variability in small increments. We describe the development of a real world testing platform on which the evolved neurocontrollers can be tested.
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Mei, Qiang. "A Solar Power System for High Altitude Airships". University of Toledo / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1306077427.
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Mastretta-Yanes, Alicia. "Landscape genomics of tropical high altitude plant species". Thesis, University of East Anglia, 2014. https://ueaeprints.uea.ac.uk/52157/.
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Changes to species distributions involve demographic processes that occur over generations and affect allele frequencies within populations, leading to patterns of genetic restructuring. The specific genetic structuring patterns that will be observed as a consequence depend on explicit geographical features, such as topography and latitude. Over the first decades of phylogeography, the effect of climate history and geography on species genomes was examined at low resolution with DNA sequences and other traditional molecular markers. However, During the last five years it has become feasible to obtain genomic data for non-model organisms and large sample sizes. The present thesis spans the transition years between phylogeographic studies being restricted to low resolution molecular markers, and new methods facilitating the generation of genomic data for non-model species. As such, this thesis focuses on two main points. First, on the methodological aspects of utilising double digest RAD-seq (ddRAD) for individual-based population genetics and phylogeography of plant species. Second, on applying the obtained data to examine one of the classic. but as yet not fully explained, biodiversity patterns: the biodiversity excess within tropical mountains. The main contributions of this thesis at the methodological level are; (1) demonstrating the utility of DNA replicates for the estimation of genotyping error and optimisation of de novo assembly; (2) proposing a method for identifying paralogous loci resulting from recent gene duplications; and (3) showing that such logi provide a measure of population differentiation. Regarding the drivers of biodiversity excess within tropical mountains, I used landscape genomic analyses and ddRAD data to examine two plant species from the alpine grasslands of the Transmexican Volcanic Belt. As a main result, this thesis supports from a population-level perspective that tropical mountains; (1) allow for long-term in situ population persistence; and (2) promote population differentiation as a function of topographic isolation.
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Waara, Martin. "High altitude ion heating observed by the Cluster spacecraft". Doctoral thesis, Umeå universitet, Institutionen för fysik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-43611.
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This thesis deals with heating of outowing oxygen ions at high altitude above the polar cap using data from the Cluster spacecraft. oInospheric plasma may flow up from the ionosphere but at velocities which are low enough that the ions are still gravitationally bound. For the ions to overcome gravity, further acceleration is needed. The cusp/polar cap is an important source of outowing oxygen ions. In the cusp/polar cap, transverse heating is more common than eld-aligned acceleration through a magnetic eld-aligned electric eld. It is thus believed that transverse heating of ions is important for ion outow and one of the probable explanations for transverse heating is wave-particle interaction. A general conclusion from our work on high altitude oxygen ion energization is that ion energization and outow occur in the high altitude cusp and mantle. The particles are often heated perpendicularly to the geomagnetic eld and resonant heating at the gyrofrequency is most of the time intense enough to explain the observed O+ energies measured in the high altitude (8 { 15 Earth radii, RE ) cusp/mantle region of the terrestrial magnetosphere. The observed average waves can explain the observed average O+ energies. At lower altitude only a few percent of the observed spectral density around the oxygen gyrofrequency needs to be in resonance with the ions to obtain the measured O+ energies. A difference as compared to low altitude measurements is that we must assume that almost all wave activity is due to waves which can interact with the ions, and of these we assume 50 % to be left-hand polarized. We also have shown a clear correlation between temperature and wave intensity at the gyrofrequency at each measurement point. We have described the average wave intensity and corresponding velocity diffusion oeffcients as a function of altitude in a format convenient for modelers. Furthermore we have shown that the wave activity observed in this high altitude region is consistent with Alfven waves, and inconsistent with static structures drifting past the spacecraft. We have also shown how large the variability of the observed spectral densities is, and how sporadic the waves typically are. Based on three cases we have found that the regions with enhanced wave activity and increased ion temperature are typically many ion gyro radii in perpendicular extent.
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Fitzsimmons, Joeleff T. "Development of a tethered, high-altitude, rigid-wing platform". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq29366.pdf.
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Wahlers, Kristen Erin. "A Design for a High Altitude Flight Test System". MSSTATE, 2006. http://sun.library.msstate.edu/ETD-db/theses/available/etd-04162006-163320/.
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Small UAV?s and flight vehicles in other atmospheres such as Mars are characterized by low Reynolds numbers. Low Reynolds number airfoil testing has been difficult to achieve and there are few centers that can accomplish this task. This study is an effort to develop a flight test system that will enable low Reynolds number tests to be performed with a simple glider design. The concept is to develop a high altitude glider that will be transported to altitudes reaching 100,000 feet or more by a helium filled balloon. At altitude, the glider will be released and will perform flight experiments as it descends. This region of Earth?s atmosphere, ?near space? has the conditions desired for low Reynolds number testing as well as similar properties to the surface of Mars. With the knowledge gained from this experiment, a better understanding of accomplishing flight on Mars may be attained.
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Foo, Yu Chiann. "Call admission control for high altitude platform station UMTS". Thesis, University of Surrey, 2002. http://epubs.surrey.ac.uk/689/.
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Acosta, Marcus P. "High altitude warfare : the Kargil Conflict and the future /". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03Jun%5FAcosta.pdf.
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Thesis (M.A. in National Security Affairs)--Naval Postgraduate School, June, 2003.Thesis advisor(s): Peter Lavoy, Douglas Porch. Includes bibliographical references (p. 79-83). Also available online.
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Aziz, Imran. "Design of a High Altitude Wind Power Generation System". Thesis, Linköpings universitet, Maskinkonstruktion, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-104569.
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One of the key points to reduce the world dependence on fossil fuels and the emissions of greenhouse gases is the use of renewable energy sources. Recent studies showed that wind energy is a significant source of renewable energy which is capable to meet the global energy demands. However, such energy cannot be harvested by today’s technology, based on wind towers, which has nearly reached its economical and technological limits. The major part of the atmospheric wind is inaccessible to the conventional wind turbines and wind at higher altitude is the major source of potential energy which has not been fully exploited yet. The thesis paper has presented a study aimed to devise a new class of wind generator based on extracting energy from high altitude wind.A brief theoretical study is presented to evaluate the potential of an innovative high altitude wind power technology which exploits a tethered airfoil to extract energy from wind at higher altitude. Among the various concepts proposed over last few decades, a kite power system with a single kite is selected for the design purpose.The designed ground station is an improvisation over existing prototypes with an energy reservoir for having a continuous power output. A flywheel is used as the energy storage system which stores the extra energy during traction phases and supplies it during recovery phases and thus giving a continuous power generation regardless of the kite’s motion and keeping the rotor speed in a permissible range defined by the design constraints. Manufacturability of the structure, availability of the components, safety and maintenance criteria have been taken into account while building the ground station CAD model.A dynamic simulation model is developed to investigate the power transmission system of the kite power unit which reflects the torque, speed and power behaviour of the modelled ground station driveline. The functionality of the designed model for the selected concept is tested with several numerical and graphical examples.
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Levett, D. Z. H. "Adaptions of exercise energetics and performance to high altitude". Thesis, University College London (University of London), 2014. http://discovery.ucl.ac.uk/1450243/.
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There is wide inter-individual variability in the reduction of exercise capacity at altitude, and the factors underlying this remain obscure. In this thesis, I used well-validated cardiopulmonary exercise testing paradigms in a large healthy volunteer cohort to interrogate exercise intolerance from an integrative physiological systems perspective. I focused on the mechanisms that contribute to human endurance performance at altitude, including oxygen transport, the efficiency of oxygen utilization, ventilatory control and cerebral oxygenation. I found that the lactate threshold (LaT) and thus sustainable exercise is relatively preserved at altitude in comparison with peak exercise (V ̇O_2 peak) and furthermore that there is some recovery of the LaT with prolonged altitude exposure (whilst V ̇O_2 peak remains depressed). A greater reduction in exercise capacity at altitude was predicted by higher sea level V ̇O_2 peak, lower peak ventilation at altitude, lower maximum heart rate at altitude and lower [haemoglobin] at altitude. After prolonged altitude exposure and at extreme altitude normalisation of oxygen content did not restore performance suggesting that some or all of systemic flow (reduced cardiac output), regional flow (pulmonary steal) or microcirculatory function and tissue diffusion limitation contribute to exercise limitation. At 7950m, flattening of the oxygen pulse suggests either limitation of stroke volume and/or a-v oxygen extraction. I found neither evidence of mechanical ventilatory limitation at V ̇O_2 peak nor of any association between cerebral oxygenation and V ̇O_2 peak. I found a subtle increase in gross efficiency (GE) on short-term exposure to 5300m, the physiological significance of which is uncertain. At extreme altitude (6400m) and after sustained exposure to 5300m, I found significant increases in GE that may be explained by changes in mitochondrial efficiency or may relate to weight loss. Future work should focus on the role of regional and microcirculatory flow in exercise limitation and mitochondrial function in exercise efficiency.
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Paxton, Brendan. "Systems Design and Experimental Evaluation of a High-Altitude Relight Test Facility". University of Cincinnati / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1448037233.
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Simmons, Grant H. 1981. "Cutaneous vasodilation at simulated high altitude: Impacts on human thermoregulation and vasoconstrictor function". Thesis, University of Oregon, 2008. http://hdl.handle.net/1794/9495.
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xvii, 174 p. : ill. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number.During acute altitude exposure, humans maintain higher skin temperature and lower core body temperature. However, the role of cutaneous vascular regulation in these thermoregulatory differences is unclear. Therefore, the purpose of these studies was to investigate the impact of altitude exposure on reflex control of skin blood flow and core temperature during cold exposure. In Chapter IV, the effects of hypoxia and hypocapnia on cutaneous vasoconstriction during mild cold exposure were investigated. We found that hypoxia stimulates cutaneous vasodilation in men whereas skin blood flow is unaltered in women. However, during whole body cooling skin blood flow is upward shifted in both sexes. The development of hypocapnia does not affect the vascular response to hypoxia in either sex, but reduces the magnitude of cutaneous vasoconstriction during cold exposure by 50% in women. In Chapter V, we studied the timecourse of α-adrenergic blockade by yohimbine in the cutaneous circulation and how the duration of cold exposure modulates cotransmitter-mediated vasoconstriction during cold stress. We found that yohimbine produces functional α-adrenergic blockade within 30 minutes of initial delivery and completely abolishes reflex cutaneous vasoconstriction during mild cold stress. This latter finding was surprising, and an additional protocol demonstrated that cotransmitter-mediated vasoconstriction only participates in the vascular response to cold stress when the exposure is more prolonged. In Chapter VI, the effects of hypoxia on cutaneous vasoconstrictor mechanisms and core cooling rate were tested during more prolonged and severe cold stress. In contrast to our findings during brief cold exposure, we showed that cutaneous vasoconstriction during prolonged cold stress is potentiated by hypoxia and abolishes hypoxic vasodilation. Moreover, increased cotransmitter-mediated vasoconstriction appears to account for this response. Hypoxia had no effect on core cooling rate during severe cold exposure. The selective potentiation of cotransmitter-mediated vasoconstriction observed during hypoxia in Chapter VI provided the basis for Chapter VII. This study was designed to test the effect of hypoxia on cutaneous vascular responsiveness to peripherally stimulated sympathetic vasoconstriction. The results demonstrated that α-adrenergic vasoconstrictor transduction is not affected by hypoxia, and that stimulation of adrenergic nerves with tyramine does not elicit cotransmitter-mediated vasoconstriction in skin.
Adviser: John R. Halliwill
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Thompson, C. J. "ACE insertion/deletion polymorphism and human performance at high altitude". Thesis, University College London (University of London), 2013. http://discovery.ucl.ac.uk/1417080/.
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The hypoxia of high altitude (‘hypobaric hypoxia’) presents a profound physiological challenge to the human body and at extreme high altitude the human body nears the limits of its tolerance for oxygen deprivation. Physical performance in this environment is limited by two major physiological elements: ‘acclimatisation’ to hypobaric hypoxia sufficient to allow strenuous physical exertion, and the avoidance of Acute High Altitude Illnesses (AHAI). The rate and effectiveness of acclimatisation and the susceptibility to AHAI varies markedly between individuals, suggesting a possible genetic influence on high altitude performance. A polymorphism of the human Angiotensin Converting Enzyme (ACE) gene has been identified in which the deletion (D-allele), rather than the insertion (I-allele), of a 287 base pair sequence is associated with higher circulating and tissue ACE activity. This polymorphism has also been associated with physical performance phenotypes, the ACE I-allele being associated with elite endurance performance. An excess frequency of the ACE I-allele has also been identified in a small sample of elite UK high altitude mountaineers. This thesis set out to test the hypothesis that the ACE I-allele is indeed associated with successful physical performance at high altitude, and to explore the mechanism by which such an advantage may be mediated. I conducted a series of prospective geneenvironment interaction studies to assess whether the ACE I-allele is associated with successful ascent to high altitude and, if such an advantage exists, whether this is mediated by reduced susceptibility to Acute Mountain Sickness (AMS) or improved oxygen saturations. To further define the underlying mechanism, I explored the association of bradykinin 2 receptor genotype with high altitude performance to investigate whether the ACE I allele contribution is mediated by increased kinin activity. Additionally I extended these observations to those who have faced the most extreme hypoxic challenge - a successful ascent of Mount Everest.
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Brizon, Mathilde. "Solar Energy Generation Model for High Altitude Long Endurance Platforms". Thesis, KTH, Flygdynamik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-180278.
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For designing and evaluating new concepts for HALE platforms, the energy provided by solar cells is a key factor. The purpose of this thesis is to model the electrical power which can be harnessed by such a platform along any flight trajectory for different aircraft designs. At first, a model of the solar irradiance received at high altitude will be performed using the solar irradiance models already existing for ground level applications as a basis. A calculation of the efficiency of the energy generation will be performed taking into account each solar panel’s position as well as shadows casted by the aircraft’s structure. The evaluated set of trajectories allows a stationary positioning of a hale platform with varying wind conditions, time of day and latitude for an exemplary aircraft configuration. The qualitative effects of specific parameter changes on the harnessed solar energy is discussed as well as the fidelity of the energy generation model results.
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Liu, Yiming. "Radio resource management for a multiple high altitude platform system". Thesis, University of York, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.440732.
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Paro, Autumn D. "Modeling High Altitude Electron Density Plumes Using Direct Numerical Simulation". Digital WPI, 2014. https://digitalcommons.wpi.edu/etd-theses/210.
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Electron densities form field-aligned structured regions in the natural ionosphere and after a high altitude nuclear explosion (HANE). These electron densities, known as plumes, are made up of many smaller individual field-aligned regions called striations. Striation modeling for systems effects has traditionally been done use a statistical approach. This statistical approach evolves different moments of the electron density. Due to lack of test data it has never been validated. The purpose of this project was to use a direct numerical simulation to solve equations governing the differential motion of individual striations. It was done in five steps: 1) Transport a single striation, 2) solve potential equation, 3) combine transport and potential equations, 4) optimize combined solver, and 4) simulate a fully-striated plume for comparison with the statistical model.
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Gomes, Themis de Brito Abagge e. Varella. "High-altitude operations for a typical 70 - seat-regional jet". Instituto Tecnológico de Aeronáutica, 2005. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=687.
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Civil aircraft manufactures seek profitable subsonic transport category operations above 40.000 feet through new and advanced civil aircraft projects, in order to meet with modern airline needs. This is due to the increase of air traffic below this altitude, as well as lower operational cost, and more efficient engines above this altitude. The Federal Aviation Administration (FAA), responsible for certification of aeronautical products in the United States has adapted requirement 14 CFR 25.841(a) for high-altitude operations, based on the numerous executive jets that operate at altitude above 40.000 feet and have obtained their type cetificate based on special conditions1. Although the FAA is considering revising this regulation, there is not enough physiological substantiation to do so at this time. This way, aircraft with wing-mounted engines cannot fully comply with this requirement and petition for a exemption which is always required. A trade-off analysis of a typical 70-seater regional jet, with wing-mounted engines, for high altitude operation trends has been completed. Aspects such as operational and economical advantages, certification and compliance impacts were considered.
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Read, Robert William. "Experimental investigations into high-altitude relight of a gas turbine". Thesis, University of Cambridge, 2008. https://www.repository.cam.ac.uk/handle/1810/224982.
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This thesis describes experiments to investigate high-altitude relight of a lean direct injection (LDI) combustor. The features that make LDI technology less polluting in terms of NOx compared to conventional combustors are expected to impede relight performance. Therefore an improved understanding of ignition behaviour is required to ensure that stringent relight requirements can be satisfied. Realistic operating conditions are simulated in a ground-based test facility. The application of laser diagnostics presents particular difficulties due to the large quantities ofliquid fuel that impinge on the combustor walls during relight. Advances are made in the application of planar laser-induced fluorescence (PLIF) to monitor fuel placement in a combustor under these conditions. A novel apparatus is developed to deliver a laser sheet to the combustion chamber while protecting all optical surfaces from contamination. The PLIF images are compared with the cold flow field obtained from CFD modelling. These results indicate that fuel becomes trapped inside the central recirculation zone in highconcentrations. High-speed flame imaging performed simultaneously with the PLIF measurements provides important insights into the motion and breakup of flame during relight. An algorithm developed to track the flame activity reveals that the initial spark kernel is convected downstream, before breaking apart and moving upstream towards a recovery origin close to the fuel injector. Analysis of many ignition events has revealed several distinct modes of ignition failure.
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Kacala, Jeffrey C. y Corey M. Collier. "A cost-effectiveness analysis of tactical satellites, high-altitude long-endurance airships, and high and medium altitude unmanned aerial systems for ISR and communication missions". Thesis, Monterey, California. Naval Postgraduate School, 2008. http://hdl.handle.net/10945/3934.
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Before 1991, the United States military's demand for additional communications bandwidth and timely intelligence was rising rapidly. Since then, with the advent of the Global War on Terrorism, it has increased substantially. To address this growing need, the Department of Defense has focused its acquisition and procurement efforts on obtaining new communications and intelligence, surveillance, and reconnaissance (ISR) platforms that can help lessen shortfalls and possibly exploit new, untapped resources. Recently, there has been an increasing focus on new technology, such as tactical satellites or high-altitude long-endurance airships, as a way to increase communications and intelligence collection capacities. Likewise, advances in the capabilities of medium-altitude and high-altitude unmanned aerial systems have resulted in a more prominent role for them on today's battlefield. Each of these vehicles has a unique niche in today's military, but the increasing capabilities of each are beginning to create some overlap in their uses. This study will conduct a cost-effectiveness analysis on these systems for use as a persistent communications and ISR platform. In particular, it will measure the effectiveness of each for comparison, and will offer possibilities to increase the overall effective use of the three together to maximize performance and cost.
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Collier, Corey M. Kacala Jeffrey C. "A cost-effectiveness analysis of tactical satellites, high-altitude long-endurance airships, and high and medium altitude unmanned aerial systems for ISR and communication missions". Monterey, Calif. : Naval Postgraduate School, 2008. http://edocs.nps.edu/npspubs/scholarly/theses/2008/Sept/08Sep%5FCollier.pdf.
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Thesis (M.S. in Space Systems Operations)--Naval Postgraduate School, September 2008.Thesis Advisor(s): Welch, William J. "September 2008." Description based on title screen as viewed on November 5, 2008. Includes bibliographical references (p. ). Also available in print.
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Blass, Alexander J. H. "Sediments of two high-altitude Swiss lakes as high-resolution late Holocene paleoclimatic archives /". [S.l.] : [s.n.], 2006. http://www.zb.unibe.ch/download/eldiss/06blass_a.pdf.
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Leitner, Andreas Rodolfo. "Improvement of Mexican high altitude waste stabilisation pond effluents for reuse". Thesis, University of Surrey, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.417536.
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Chang, J. M. "A flexible, subsonic high altitude long endurance UVA conceptual design methodology". Thesis, Cranfield University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245445.
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Winterhalder, Ralph Martinelli Michele. "Muscle degenerative and regenerative changes with high altitude exposure in humans /". Bern, 1989. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.
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Bakari, Salim Rashid. "Solar panel development for high altitude and low earth orbit application". Thesis, Cape Peninsula University of Technology, 2010. http://hdl.handle.net/20.500.11838/2208.
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Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2010.Stable and reliable source of electrical energy is a requirement for efficient operation of satellites. Several sources of electrical power for satellites exist such as fuel cells, nuclear or battery stored Direct Current energy but of late concentration has been on solar cells as the advantages compared to the other sources are many. Solar cells are p-n semiconductor devices which convert light energy into electrical energy by photovoltaic effect. The biggest drawback of solar cell energy system is the low light to electricity conversion efficiency. Apart from powering satellites, solar cells and panels have found other numerous applications such as in water pumping systems, rural electrification, street lightning. Photovoltaic principle of solar cells started way back in 1839 when Alexandre Edmund Becquerel observed that electrical currents arose from certain light induced chemical reactions. A comprehensive understanding of this phenomenon became clear when the science of quantum theory was unveiled in the early parts of the 20th century. Most solar cells and panels available today in the market are silicon based made of single junction technology. The disadvantage with single junction technology is that the p-n junction is made of a single type of solar cell material which absorbs a fraction of light wavelengths from the spectrum of light. The disability of the single p-n junction to convert all the light energy to electricity accounts for the low efficiency for the solar cells. One way to go around the problem of efficiency is to use multi-junction solar cells. Multijunction solar cells are designed to absorb a large fraction of the light spectrum and convert them to electrical energy. They are made of multiple p-n junctions made of different solar cell materials which absorb different parts of light spectrum and convert them to electrical energy. In this thesis, a design of a multi-junction solar cell for developing space solar panel is presented. The multi-junction cell has been designed from simulation results of different solar cell materials simulated with space conditions. Ideas and recommendations for future work are also presented.
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Nordqvist, Emil. "Preliminary design of a modular high altitude balloon power distribution system". Thesis, Luleå tekniska universitet, Institutionen för system- och rymdteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-79762.
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This thesis conducts research into different rechargeable battery technologies and their applicability to the high altitude balloon flights conducted at Esrange space center. The research focuses on the possible use of lithium ion batteries’, sodium ion batteries, nickel metal hydrate, and Metal hydridelithiumion batteries. Resulting in lithium ion batteries in 18650 cells being recommended. The thesis continues with a modular power distribution system architecture design. The system architecture is established with solarcharging capabilities, up to 1500W peak output power, over 600W continuous output power, multiple output voltages, more than six output channels, remote output power switching, and monitoring of power consumption. A prototype is built from this architecture on which limited testing is performed.The testing shines light on future improvements and displays proof of concept for some parts.
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Racine, Evan Michael. "Experimental Study - High Altitude Forced Convective Cooling of Electromechanical Actuation Systems". University of Dayton / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1450286609.
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Sanchez, Maria Elisa. "Carbon flux dynamics in high altitude peatlands in the Ecuadorian Andes". Thesis, Michigan Technological University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10241527.
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Although knowledge of peatland CH4 and CO2 exchange in temperate mountain ecosystems is available, information about carbon (C) exchange in peatlands of the Andean mountains is limited and these ecosystems may behave differently given the particular characteristics of the Andean tropics. These ecosystems are highly productive and under pressure by grazing. Our first objective was to measure baseline carbon dioxide (CO2) and methane (CH4) flux in an undisturbed peatland in Cayambe-Coca National Park. Our second objective was to quantify CO2 and CH 4 fluxes in an intensively cattle grazed peatland near Antisana Ecological Reserve. CO2 and CH4 effluxes were measured using a static chamber method. The mean NEE values for the undisturbed and disturbed site were -0.69 ± 0.08 and -1.25 ± 0.13 g CO2 m -2 hr-1 respectively. A significant correlation between microtopography and CO2 and CH4 flux was found in the undisturbed site, with higher NEE, GPP, ER and CH4 values in hummocks than in lawns. Microtopography doesn’t seem to be a controller of CO 2 efflux in the grazed site, although the NEE and GPP rates are higher than those found in the undisturbed site, and show a linear relationship with vegetation cover. CH4 emissions in the undisturbed site were low (8.1 ± 1.17 mg CH4 m-2 d -1). However, CH4 emissions at the grazed site were very high (132.25 ± 34.22 mg CH4 m-2 d -1), which might be attributed to the high physical impact and inputs from cattle. In summary, it appears that cattle grazing may be capable of large changes to C exchange and greenhouse gas fluxes in Andean peatlands.
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Hasan, Md Al-Mahadi y Mainul Islam. "Improving the System Performance of High Altitude Platforms Serving Suburban Areas". Thesis, Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-5071.
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High Altitude Platforms (HAP) has been evolving to make a new history in wireless communications infrastructure. A number of applications and services have been proposed for HAP based communications which advance HAP over terrestrial and satellite infrastructure for future communications. Providing high speed multimedia mobile communications through HAPs to the users of Third Generation (3G) holds strong position using one of the proposed band, 2GHz. In this study we investigated how to improve the performance of 3G serving from HAP over a territory having suburban characteristics. Two proposed channel models, free space loss and shadowing loss, has been used to analyze the performance of HAP systems at 2GHz frequency band for suburban regions. Three different parameters namely antenna bore point, HAP antenna roll off factor and user antenna roll off factor have proposed to improve the performance of HAP systems while considering suburban regions. A scenario has introduced consisting of an ideal suburban and rural region to serve 3G services while emphasizing on suburban region. The number of HAPs required to serve the defined suburban region is restricted to at least three due to elevation dependent losses in the scenario. The three proposed parameters have been used to improve the performance of 3G services over the selected suburban region. Application of the parameters over suburban region gives different performances which can be categorized in different ways. Some of the parameters are more elastic than others for a certain coverage area. We conclude with adaptive application of the parameters for 3G services over suburban area to have improved performance of HAP.+46720459586
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Rose, Clémence. "Nucléation et formation de nouvelles particules à haute altitude". Thesis, Clermont-Ferrand 2, 2014. http://www.theses.fr/2014CLF22507/document.
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La formation de nouvelles particules est un processus complexe à l’origine d’une fraction importante des concentrations en nombre de particules observées dans l’atmosphère. En jouant le rôle de noyau de condensation (CCN) pour la formation des gouttelettes de nuage, les particules issues de ce processus impactent le bilan radiatif terrestre. Fréquemment observée et documentée à basse altitude, la formation de nouvelles particules a plus rarement fait l’objet d’études à haute altitude. L’analyse des données obtenues en 2012 à la plus haute station du monde, Chacaltaya (5240 m, Bolivie) révèle une fréquence d’observation annuelle du processus remarquablement élevée (64%), avec de nombreux évènements multiples. Les mesures conduites à la station du puy de Dôme (1465 m, ACTRIS, GAW) qui bénéficie d’un dispositif instrumental rare ont plus particulièrement permis de mettre en évidence le déroulement du processus en troposphère libre. Une analyse complète de l’extension verticale du processus rendue possible grâce aux données aéroportées obtenues au-dessus du bassin Méditerranéen dans le cadre du projet HYMEX (MISTRALS, automne 2012) a montré qu’en plus d’être observé à haute altitude, le processus de formation de nouvelles particules semblait y être clairement favorisé, avec une probabilité d’observation multipliée par 10 au-dessus de 1000 m. De plus, à ces altitudes le processus de formation de nouvelles particules pourrait être une source importante de CCN, comme le suggèrent les résultats obtenus à Chacaltaya, où dans 68% des évènements analysés les particules formées atteignent des diamètres suffisants pour jouer le rôle de CCN. La diversité des environnements associés aux bases de données utilisées a également permis d’apporter des éléments relatifs à la compréhension du processus du point de vue de la charge des embryons formés, de l’identité des précurseurs gazeux impliqués et des paramètres atmosphériques influençant le processus. Ces éléments sont déterminants pour une prise en compte optimale du processus de formation de nouvelles particules dans les modèlesNew particle formation (NPF) results from a complex sequence of multiple processes and contributes to an important fraction of the total atmospheric aerosol number concentration. After they grow, newly formed particles can act as cloud condensation nuclei (CCN), and thus have indirect effect on the Earth radiative balance through cloud related radiative processes. While NPF has often been observed and studied at low altitudes, the occurrence of the process is poorly documented in the literature for high altitude sites. We report a high annual frequency of the NPF process (64%) at the highest measurement site in the world, Chacaltaya (5240 m, Bolivia), in 2012, with frequent multiple events. At the puy de Dôme station (1465 m, ACTRIS, GAW), the occurrence of NPF in the free troposphere was detected using a unique instrumental setup. A complete analysis of the vertical extension of the NPF process was performed based on airborne measurements conducted above the Mediterranean basin in the frame of the HYMEX project (MISTRALS, September – November 2012). Our observations suggest that NPF could be favored at high altitudes with a probability of occurrence increased by 10 above 1000 m. At these altitudes, NPF could significantly contribute to the production of CCN, since 68% of the analyzed events show particle growth up to CCN sizes at Chacaltaya. The high number of observations recorded in various environments also contributed to improve our knowledge regarding the charge of the nucleated clusters, the identity of the gaseous precursors and the atmospheric parameters influencing the NPF process. This will allow a better parameterization of the NPF process in modelling tools