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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
571

Surface movement due to coal mining and abandoned mine flooding

Zhao, Jian 12 July 2022 (has links)
To better understand the issues about the surface movements in the coal mining region Lugau-Oelsnitz, Germany, small-scale numerical models are firstly utilized for verifications via analytical solutions, to explore the simulation schemes, and for parameter sensitivity analysis. 1D rock column numerical models shows that simulated surface movements are consistent with analytical solutions. The investigations via 2.5D profile numerical models also show that uplift is linear related to water level rise under confined mine water conditions, while a quadratic function is valid for unconfined mine water. Geodetic survey in the Lugau-Oelsnitz district shows that at the end of the active mining period (1844 to 1971), general subsidence is about 5 - 10 m, with a maximum of 17 m in the southern mining area. General uplift velocity after abandoned mine flooding between 1972 and 2014 is about 0.5 - 2.0 mm/year. Based on numerical simulation results, predicted general uplift velocity vary between 0.5 - 3.0 mm/year, while maximum uplift position is moving toward south.:1 Introduction 2 State of the art 2.1 Overview 2.1.1 Coal mining induced settlements 2.1.2 Flooding induced uplift 2.2 Approaches to predict subsidence 2.2.1 Empirical approaches 2.2.2 Influence function methods 2.2.3 Physical models 2.2.4 Numerical simulation methods 2.3 Approaches to predict uplift 2.3.1 Empirical approaches 2.3.2 Numerical simulation methods 2.4 Comparison and conclusions 2.4.1 Comparison of research methods 2.4.2 Conclusions 3 Numerical simulation approaches 3.1 Continuum mechanical simulations with FLAC3D 3.1.1 Mining induced subsidence 3.1.2 Flooding induced uplift 3.2 Discontinuum mechanical simulations with 3DEC 3.2.1 Self-weight induced settlement in jointed rock column model 3.2.2 Uplift for jointed and fully saturated rock column 3.3 Parameter sensitivity study 3.3.1 Parameter effect on subsidence 3.3.2 Parameter effect on uplift 3.4 Interface and volume element representation of faults 3.4.1 Simulation schemes 3.4.2 Parameter sensitivity analysis of fault 3.4.3 Discussion 3.5 Conclusions 4 Case study: Coal mining region Lugau-Oelsnitz 4.1 Background information 4.1.1 Mining background 4.1.2 Geological and hydrogeological situation 4.2 In-situ monitoring data 4.2.1 Groundwater level data 4.2.2 Surface movement data 4.2.3 Discussion of data analysis 4.3 Continuum based numerical modelling 4.3.1 Introduction 4.3.2 Model set-up 4.3.3 Calculation results 4.3.4 Surface movement predictions 4.4 Discontinuum based numerical modelling 4.4.1 Model set-up 4.4.2 Calibration results 4.4.3 Surface movement prediction 4.5 Conclusions 5 Conclusions and prospects 5.1 Conclusions 5.2 Main contributions of thesis 5.3 Inadequacies and prospects
572

The influence of temporal rainfall distribution and storm movement on flood depth in urban pluvial cloud burst modeling / Inflytandet av regnets tidsfördelning och stormens rörelse på översvämningdjup inom modellering av urbana pluviala skyfall

Henrich, Michael January 2019 (has links)
Pluvial floods are the most difficult and to date least investigated phenomena in urban hydrology. While efforts are being made to increase the knowledge base concerning this type of flooding, a large part of the difficulty lies in the nature of the precipitation. Convective storms represent most of the larger intensity short term rainfall in urban areas and is also the raintype, that is expected to increase the most in the future. The rain cells of this type have a more distinct boundary, larger intensity, a smaller extent and a shorter life span, than frontal rains. Combined with the low availability of densely spaced rain gauge networks and also low temporal resolution of measurements in 15 minutes intervals at best, makes this rain type still very difficult to analyze and even harder to predict. The resolution of cloud radar images at 2x2km and taken every 15 minutes is too coarse and the error reduction algorithms for radar based precipitation (HIPRAD) images to analysera in patterns are not sufficient by them selves to analyze the characteristics of such rainfields and the processes occurring within these fields. The spatial variation of raincells, their development and decay, the distance between them, and the velocity and direction of their movement can however be investigated employing a combination of densely spaced rain gauges and radar images to reach a more realistic representation of short-term precipitation for the use of in hydraulic models. The movement of rain fields has been investigated with two main areas of focus: The influence of direction or directional bias, often with an interest in the most crucial case referred to as the resonance effect, and in context of areal reduction of point rainfall. Most of these studies have been carried out with statistical methods and in laboratory experiments. In this study a hydraulic model was built on the terrain model of a realcity, a 28 km area in the city of Falun, to test the recently gathered information about the temporal variation of five empirical hyetographs with different peak arrival times and peak intensities, which are representative of Swedish climate. The hyetographs were produced and provided by SMHI. The empirical rain types were derived from 20 years of rain gauge observations and confirmed by radar images. For reference purposes, a standard Chicago design storm (CDS) rain was modeled as well. The simulated scenarios were modeled as a MIKE 21 hydraulic model, as a stationary scenario and in four movement directions. It was foundthat the empirical rain types produced lower inundation depth than the CDS, in a range of 20 to 50 % lower. The effect of modeling rainfall in motion produced on average only about 4-20 % lower water depths than the corresponding non-moving scenario. In a few instances, in a single evaluation point, the moving scenarios resulted in a relative water depth of a maximum of just above 1%. It was concluded that the conceptual approach of areal reduction from movement seems to be accurate and could help improve modeling rainfall in general, and specifically for cloud burst scenarios of shorter durations in urban catchments. It was also found that further investigation of the physical processes in rainfields could serve to increase the accuracy in areal reduction of precipitation for more realistic hydraulic models and in turn reduce over design. / Pluviala översvämningar är den typen, som är både svårast att reda ut och samtidigt den minst utforskade fenomenen inom urban hydrologi. Medan ansträngningar görs för att förbättra kunskapsläget, ligger den största svårigheten i nederbördens skepnad. Det är konvektiva regn som utgör de flesta av de starkare korttids regntillfällen i urbana områden och är också regntypen som förväntas att öka mest i framtiden. Regncellerna har en tydligare avgränsning, en större intensitet, mindre utsträckning, och en kortare livscykel än frontala regn. I kombination med den låga tillgängligheten av regnmätarnätverk med hög täthet i positioneringen av mätare, samt den låga tidsupplösningen av mätningar i intervaller av 15 minuter gör att konvektiva regn fortfarande är svåra att analysera och ännu svårare att förutse. Upplösningen av molnradar bilder av 2x2 km som tas varje 15:de minut är för grova och algoritmer för felreducering av bilder från radarbaserad nederbördsdata (HIPRAD) för analys av regn mönster är inte tillräckligt noggranna, för sig, för att kunna analysera egenskaperna av sådana regnfält och de processerna som karakteriserar dessa. Den spatiala variationen inom regnceller, deras utveckling och förfall, avståndet mellan dem samt riktningen och hastigheten kan ändå undersökas med hjälp av kombinationen av regnmätarnätverk och radar bilder för att uppnå mer realistiska korttids nederbördsscenarier för användning i hydrauliska model. Studier, som har undersökt regn i rörelse har varit fokuserade på två huvudområden: Betydelsen av riktningen, i vilken regnet rör sig, där den största effekten som denna riktningsbias kan uppnå, har döpts resonans effekt och i samband med ytreducering (areal reduction) av punkt nederbörd. De flesta av dessa studier har genomförts med hjälp av statistiska metoder och laboratorieexperiment. I denna studie skapades en hydraulisk modell baserad på en realistisk terräng av ett existerade urbant område, en yta på 28 km i Falun, för att testa den nyligen utvärderade informationen om temporala intensitets fördelningen som representerar det svenska klimatet. Regndatat producerades och tillhandahölls av SMHI och representerar en mätserie från regnmätare över en period av 20 år. Som referens modellerades även ett Chicago regn (CDS). Med hjälp av en MIKE21 hydraulisk modell, simulerades ett stationärt scenario och fyra rörelseriktningar för varje empirisk hyetograf. Resultaten visade att de empiriska regntyperna skapade översvämningar med 20-50% lägre vattendjup än CDS regnet. Att modellera rörelsen resulterade i 4-20% lägre vattennivåer jämfört med respektive stationär scenario. I några enstaka tillfällen, i en av evalueringspunkterna, skapade de rörliga scenarierna större resultat, med lite över 1% i det största fallet. Det drogs slutsatsen att konceptet av areal reduction genom molnrörelse verkar vara korrekt och skulle kunna hjälpa att förbättra sättet att modellera regn generellt, men också specifikt för skyfalls scenarier med korta varaktigheter över urbana avrinningsområden. Man kom ytterligare till slutsatsen att framtida studier i samband med de fysiska processerna i regnceller skulle kunna användas för att höja noggrannheten av ytreducering av nederbörd för mer realistiska hydrauliska modeller, som i sin tur kunde minska överdesign.
573

The Ecological and Social Effects of Gentrification and Urbanisation in Thailand's Lower Chao Phraya Delta

O'Kane, Daniel January 2022 (has links)
Rapid economic development and urban expansion of the Bangkok Metropolitan Region (BMR) places pressure on biomes and communities alike. In a world suffering from the increasing effects of climate change, unchecked urbanisation comes at the expense of carbon sequestrating environments. The modernisation, concretisation and gentrification of this low-lying, deltaic, monsoonal metropolis has seen its traditional, water-based urban morphology replaced with a solid state of perception, parallel to a loss of flood mitigating infrastructure. As the metropolis’ boundaries expand into its hinterlands, agriculturally productive land is being converted to residential, commercial and industrial development and the fate of low-income urban populations and farmers lies in the hands of speculators hoping to capitalise on increasing land values. Combatting this backdrop of neoliberal urbanisation is legislative framework intended to prevent speculation, yet it results in additional ecological damage as landowners clear natural-growth forests and mangroves to meet tax-reducing criterium. The purpose of this thesis is to examine the reasons behind and consequences of under-regulated urbanisation and gentrification and the effects this has had on the vulnerable ecology and communities of the BMR. It provides lessons on how previous short sighted and poor development regulations will have enduring social and environmental consequences long into the future and how adoption of traditional morphological ways-of-life and legislative amendments can limit further damage. The legacy of neoliberal urban development resulting in gentrification and underpinned by conflicting local planning laws are analysed and supported by various theoretical materials, field studies and interviews.
574

Hurricane Katrina and New Orleans: Discursive Spaces of Safety and Resulting Environmental Injustice

Shears, Andrew B. 19 July 2011 (has links)
No description available.
575

Etude foristique, écologique et phytosociologique des forêts de l'île Mbiye à Kisangani, RDCongo

Nshimba, Hypolite 23 January 2008 (has links)
Floristic, Ecological and Phytosociological, Study of the Forests of the Mbiye Island at Kisangani, DR Congo The Mbiye Island is situated on the Congo River, in the Eastern part of Kisangani. It is located upstream of the Wagenia Falls, between latitude 0º31’ North and longitude 25º11’ East, with 376 m of altitude. It adjoins the town of Kisangani, and it is 14 km long and 4 km wide. All around Kisangani, the Mbiye Island is the only ecosystem which has a dense forest that is relatively well preserved. This Island has an area of 1,400 ha, and it comprises three types of forest: dry land forest, periodically flooded forest and swampy forest. The main purpose of this study has been to make a qualitative and quantitative analysis of the physiognomy and structure of these three types of forest. I relied on two methods in data collecting: the Phytosociological plotting method with a sampling equal to 100 individuals for the higher strata and 100 m² grass strata, associated with dbh measure for trees whose diameter is ≥ 10 cm. In total, out of the 80 plottings, 67 multi strata and structurals each of which has been decomposed in 4 sub-plottings fit together. Based on the presence-absence criterion, the other 13 multi strata and structurals have been made into Chablis, and all the data have been globally analyzed. An inventory of 33991 individuals has been made in this study. After their identification, it has been found out that there 470 species belonging to 297 types and 90 families. Rubiaceae, Caesalpiniaceae and euphorbiaceae families have been found out to be the most important in Genus and species. In the raw spectra of biological types, the phanerophyts (83.0%) are the most predominant, and within which the mesophanerophyts (trees 10 to 30 m tall in their old age) are the most predominant (39.0%). The Phytogeographical spectra have more omni-guineo-congolese (35%) elements; and amongst the diaspore types, the sarcochores (69%) are the most predominant. 58 endemic species (12.3%) of the central forest sector have been found out at the Mbiye Island. After the classification and ordination of the 80 plottings by Twinspan and DCA, three Phytosociological groupings have been found out in the dry land forest: (1) grouping of Funtumia elastica and Albizia ealaensis, (2) grouping of Nesogordonia leplaei and Antiaris toxicaria, (3) prouping of Olyra latifolia and Campylospermum elongatum; two others for floodable forests (1) grouping of Rinorea oblongifolia and Byrsocarpus coccineus, (2) grouping of Pachystela seretii, Dracaena kindtiana and Culcasia yangambiensis, and three others for swampy forests: (1) grouping of Strombosia grandifolia, Calamus deerratus, Culcasia angolensis and Elaeis guineensis, (2) grouping of Cleistopholis patens and Pterygota bequaertii, (3) grouping of Diospyros bipendensis, Strychnos icaja and Palisota barteri and then two groupings for the Chablis plottings (1) grouping of Palisota schweinfurthii, Eremospatha haullevilleana, Thomandersia hensii and Pycnocoma insularis and (2) grouping of Nephrolepis biserrata and Scaphopetalum thonneri. The coelocaryon botryoides has shown a uniform spatial distribution in the in the forest periodically flooded, whereas Gilbertiodendron dewevrei has shown an aggregated distribution. Comparison of richness in different taxa within the sampling has given high values as far as the numbers of species is concerned and genus of the same family in the phytosociological sampling. Out of all the species listed, 189 have been considered to be common species with regard to the three forest types, other 144 belonged to two types. 90 species have been listed only on solid land, 27 on periodically flooded forest 20 on swampy forest. Euphorbiaceae, Rubiaceae and Caesalpiniaceae families were the best represented in species and genus. With regard to richness in each forest type, the forest of solid soil was the only one to have high values both in species<p>and genus, and the swampy forest was less represented. With reference to richness according to strata, the herbaceous and under-shrub stratum (H) was the richest whereas the stratum of dominant trees (E+A1) was the poorest. Mbiye island forest is the nearest one of Kisangani for which it plays the most important role with regards to supplies in different forest products and non-ligneous forest products. In total, 12.3% endemic species of Central forest sector have been listed there, but due to frequent use by man this time, all these endemic species may disappear from this island. It is therefore urgent that particular attention be paid on it. Actions of conservation and lasting exploitation must be started in order to block their extinction. Key words: DRCongo, Flora, Ecology, Phytosociology, insularity, flooding, spatial distribution, biodiversity, synusie, Mbiye Island, Kisangani./Etude floristique, écologique et phytosociologique des forêts de l'île Mbiye, Kisangani, RDCongo. L'île Mbiye est une île du fleuve Congo située dans la partie Est de la ville de Kisangani, en amont des chutes Wagenia, entre 0° 31' de latitude Nord et 25° 11' de longitude Est, avec une altitude de 376 m. Elle jouxte la ville de Kisangani et sa longueur maximale est de 14 km sur 4 km de largeur. Elle est le seul écosystème à proximité de la ville, possédant encore une forêt dense relativement bien conservée et formant un îlot de 1400 ha comprenant trois types forestiers :la forêt de terre ferme, la forêt périodiquement inondée et la forêt marécageuse. L’objectif principal de cette étude a été de faire une analyse quantitative et qualitative de la physionomie et la structure de ces trois types forestiers. Deux méthodes ont permis la récolte de données ;la méthode de relevés phytosociologiques à effort d’échantillonnage égal à 100 individus pour les strates supérieures et 100 m² pour la strate herbacée, associée à celle de mesure de D130, pour les arbres à diamètre ≥ 10 cm. Au total, 80 relevés dont 67 multistrates et structurels, décomposés chacun en 4 sous-relevés emboîtés, ont été mis en place. 13 autres ont été faits dans les chablis avec l’appréciation basée sur le critère de présence-absence et toutes les données ont été analysées globalement. A l’issue de cette étude, 33991 individus ont été recensés. Après leur identification, au total 470 espèces appartenant à 297 genres et 90 familles ont été obtenues. Les familles des Rubiaceae, des Caesalpiniaceae et des Euphorbiaceae sont les plus importantes, tant en genres qu’en espèces. Dans les spectres bruts de types biologiques, les phanérophytes (83,0 %) sont les plus abondants et au sein desquels les mésophanérophytes (arbres de 10 à 30 m au stade adulte) sont les plus dominants (39,0 %). Les spectres phytogéographiques ont montré une prédominance d’éléments omni-guinéo-congolais (35 %) alors que parmi les types de diaspores, les sarcochores (69 %) sont les plus dominants. 58 espèces endémiques du Secteur forestier central (soit 12,3 %) ont été recensées à l’île Mbiye. Après classification et ordination de ces 80 relevés par Twinspan et DCA, trois groupements phytosociologiques ont été obtenus dans la forêt de terre ferme: (1) groupement à Funtumia elastica et Albizia ealaensis, (2) groupement à Nesogordonia leplaei et Antiaris toxicaria, (3) groupement à Olyra latifolia et Campylospermum elongatum ;deux autres pour les forêts inondables (1) groupement à Rinorea oblongifolia et Byrsocarpus coccineus, (2) groupement à Pachystela seretii, Dracaena kindtiana et Culcasia yangambiensis ;trois autres encore pour les forêts marécageuses :(1) groupement à Strombosia grandifolia, Calamus deerratus, Culcasia angolensis et Elaeis guineensis, (2) groupement à Cleistopholis patens et Pterygota bequaertii, (3) groupement à Diospyros bipendensis, Strychnos icaja et Palisota barteri, et enfin, deux groupements pour les relevés de chablis (1) groupement à Palisota schweinfurthii, Eremospatha haullevilleana, Thomandersia hensii et Pycnocoma insularum et (2) groupement à Nephrolepis biserrata et Scaphopetalum thonneri. L’espèce Coelocaryon botryoides a montré une répartition spatiale uniforme dans la forêt périodiquement inondée alors que Gilbertiodendron dewevrei y a montré une répartition agrégée. La comparaison de la richesse en différents taxa au sein de relevés et de placettes a donné de valeurs supérieures en nombre d’espèces, de genres et même de familles, dans les relevés phytociologiques. Sur le total des espèces recensées, 189 ont été considérées comme espèces communes aux trois types forestiers, 144 autres appartenaient aux deux types. 90 espèces<p>n’ont été recensées qu’en forêt de terre ferme, 27 en forêt périodiquement inondée et 20 dans la forêt marécageuse. Les familles des Euphorbiaceae, des Rubiaceae et celle des Caesalpiniaceae ont été les mieux représentées en espèces et en genres. En ce qui concerne la richesse dans chaque type forestier, la forêt de terre ferme était la seule à avoir des valeurs supérieures tant en espèces qu’en genres et la forêt marécageuse était la moins représentée. Quant à la richesse spécifique selon les strates, la strate herbacée et sous-arbustive (H) était la plus riche alors que la strate des arbres dominants (E+A1) était la plus pauvre. La forêt de l’île Mbiye est la seule forêt proche de la ville de Kisangani pour laquelle elle joue un rôle de premier plan en ce qui concerne le ravitaillement en différents produits forestiers et forestiers non ligneux. Au total, 12,3% d’espèces endémiques du Secteur forestier Central y ont été recensées, mais vue l’action anthropique qu’elle connaît ce dernier temps, toutes ces espèces endémiques risquent de disparaître de cette île. Il est alors urgent qu’une attention particulière, soit tournée vers elle. Des actions de conservation et d’exploitation durable doivent être amorcées en vue contrecarrer l’extinction des celles-ci. Mots clés :RDCongo, flore, écologie, phytosociologie, insularité, inondation, répartition spatiale, biodiversité, synusie, île Mbiye, Kisangani. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished
576

Micropalaeontology, palaeoenvironments and sequence stratigraphy of the Sulaiy Formation of eastern Saudi Arabia

Alenezi, Saleh January 2016 (has links)
The Sulaiy Formation, which is the oldest unit in the Lower Cretaceous succession, is conformably overlain by the Yamama Formation and it is a challenge to identify the precise age of the two formations using foraminifera and other microfossil assemblages. In the eastern side of Saudi Arabia, the Sulaiy Formation and the base of Yamama Formation are poorly studied. The main objectives of this study is to enhance the understanding of the Sulaiy Formation sequence stratigraphical correlation, regional lateral variations and palaeoenvironmental investigation. Lithological and semi-quantitative micropalaeontological analysis of 1277 thin sections taken from core samples from nine cored wells providing a geographically representative distribution from the Saudi Arabian Gulf. These cores intersected the base of the Yamama Formation and the Sulaiy Formation in the total thickness of cored wells of 843.23 meters (2766.5 feet). On the evidence provided by the foraminifera, the Sulaiy Formation is considered to represent the Berriasian to the lowermost Valanginian. The investigation of the micropalaeontology has provided considerable insights into the biocomponents of Sulaiy and the base of Yamama formations in order to identify their biofacies. These microfossils include rotalid foraminifera, miliolid foraminifera, agglutinated foraminifera, calcareous algae, calcispheres, stromatoporoids, sponge spicules, problematica (e.g. Lithocodium aggregatum), molluscs, corals, echinoderms and ostracods. Systematics of planktic and benthic foraminifera is accomplished using the foraminiferal classification by Loeblich and Tappan (1988) as the main source. The assemblage contains foraminifera that recorded for the first time in the Sulaiy Formation. Other microfossils were identified and recorded to help in the identification of the sedimentary environments. The investigation of the micropalaeontology and the lithofacies analysis have provided evidence the identification of the various lithofacies. About twenty four microfacies were identified on the basis of their bio−component and non-skeletal grains. The lithofacies and the bio−component results have provided the evidence of the sedimentary palaeoenvironmental model namely the Arabian Rimmed Carbonate Platform. This palaeoenvironmental depositional model is characterised by two different platform regimes. They are the Platform Interior and the Platform Exterior each of which have unique sedimentary lithofacies zones that produce different types of lithofacies. Each lithofacies is characterised by special depositional conditions and palaeobathymetry that interact with sea level changes and the accommodation space. The important palaeoenvironments are intertidal, restricted lagoon (subtidal), open marine, deeper open marine, inner shoal, shoal and platform margin. Generating, and testing, a depositional model as a part of formulating a sequence stratigraphical interpretation of a region is a key to understanding its geological development and – ultimately – reservoir potential. The micropalaeontology and sedimentology of the Sulaiy Formation in the subsurface have indicated a succession of clearly defined shallowing−upwards depositional cycles. These typically commence with a deep marine biofacies with wackestones and packstones, capped with a mudstone-wackestone maximum flooding zone and an upper unit of packstone to grainstones containing shallow marine biofacies. The upper part of the Sulaiy Formation is highstand-dominated with common grainstones that host the Lower Ratawi reservoir which is capped by karst that defines the sequence boundary. This karst is identified by its abundant moldic porosity that enhanced the the reservoir quality by increasing its porosities into greater values. Integration of the sedimentology and micropalaeontology has yielded a succession of shoaling−upwards depositional cycles, considered to be 4th order sequences, that are superimposed on a large scale 3rd order system tract shallowing−upwards, highstand-associated sequence of the Sulaiy Formation. The Lower Ratawi Reservoir is located within the latest high-stand portion of a third-order Sulaiy Formation sequence. The reservoir consists of a succession of several sequences, each of which is sub-divided into a lower transgressive systems tract separated from the upper highstand systems tract by a maximum flooding surface (MFS/Z). The last of these depositional cycles terminates in beds of porous and permeable ooid, or ooidal-peloidal, grainstone. The reservoir is sealed by the finer-grained sediments of the Yamama Formation.
577

Compact air separation system for space launcher / Compact air separation system demonstrator for space launchers using in-fight oxygen collection

Bizzarri, Didier 01 September 2008 (has links)
A compact air separator demonstrator based on centrifugally enhanced distillation has been studied. The full size device is meant to be used on board of a Two Stage To Orbit vehicle launcher. The air separation system must be able to extract oxygen in highly concentrated liquid form (LEA, Liquid Enriched Air) from atmospheric air. The LEA is stored before being used in a subsequent rocket propulsion phase by the second stage of the launcher. Two reference vehicles are defined, one with a subsonic first stage and one with a supersonic first stage. In both cases, oxygen collection is performed during a cruise phase (M 0.7 and M 2.5 respectively). The aim of the project is to demonstrate the feasibility of the air separation system, investigate the separation cycle design, and assess that the separator design selected is suitable for the reference vehicles.<p><p>The project is described from original base ideas to design, construction, extended testing and analysis of experimental results. Preliminary computations for a realistic layout have been performed and the motivations for the choices made during the process are explained. Test rig design, separator design and technical discussion are provided for a subscale pilot unit. Mass transport parameters and flooding limits have been estimated and experimentally measured. Performance has been assessed and shown to be sufficient for the reference Two Stage To Orbit vehicles. The technology developed is found suitable without further optimization, although some volume and mass reduction would be desirable for the supersonic first stage concept. There are many ways of optimisation that can be further investigated. The aim of this program, however, is not to fully optimize the device, but to demonstrate that a device based on a simple, robust, low-risk design is already suitable for the launch vehicles. On top of that analysis, directions for improvements are suggested and their potentials estimated. A complete assessment of those improvements requires further maturation of the technological concept through further testing and practical implementations.<p><p>Directions for future work, general conclusions and a vehicle development roadmap have also been provided.<p> / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished
578

Digital Soil Mapping of the Purdue Agronomy Center for Research and Education

Shams R Rahmani (8300103) 07 May 2020 (has links)
This research work concentrate on developing digital soil maps to support field based plant phenotyping research. We have developed soil organic matter content (OM), cation exchange capacity (CEC), natural soil drainage class, and tile drainage line maps using topographic indices and aerial imagery. Various prediction models (universal kriging, cubist, random forest, C5.0, artificial neural network, and multinomial logistic regression) were used to estimate the soil properties of interest.

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