Dissertations / Theses on the topic 'Post Gis'
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Ткаченко, В. Ф., Н. И. Губа, and И. А. Божинский. "Архитектура и инструментальные средства создания муниципальной геоинформационной системы." Thesis, НТМТ, 2014. http://openarchive.nure.ua/handle/document/7217.
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В докладе рассматривается концептуальная архитектура муниципальной
геоинформационной системы, технология и инструментальные средства ее
создания на базе продуктов с открытым кодом PostGis/PostgreSQL.
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Vafeidis, Anthanasios. "Regional estimation of post-fire erosion using remote sensing and GIS : an example from Greece." Thesis, King's College London (University of London), 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248186.
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Rouse, L. Jesse. "Data points or cultural entities a GIS-based archaeological predictive model in a post-positivist framework /." Morgantown, W. Va. : [West Virginia University Libraries], 2000. http://etd.wvu.edu/templates/showETD.cfm?recnum=1756.
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Thesis (M.A.)--West Virginia University, 2000.Title from document title page. Document formatted into pages; contains v, 95 p. : ill. (some col.), maps (some col.). Vita. Includes abstract. Includes bibliographical references (p. 83-89).
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Brown, Daniel. "The use of geospatial tools to support, monitor and evaluate post-disaster recovery." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/274920.
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The aim of this research is to test the feasibility of using remote sensing-based information products and services to support the planning, monitoring and evaluation of recovery after disaster. The thesis begins by outlining the process of post-disaster recovery, what it entails and who is involved. The data and information needs at different stages of the disaster cycle are introduced and the importance of monitoring and evaluating post-disaster recovery is discussed. The literature review introduces the high-spatial-resolution remote sensing market and the technology focusing on current sensors’ capabilities. This is followed by a review of previous attempts to measure post-disaster recovery by practitioners and academics. At the end of the chapter a list of recovery indicators, suitable for remote sensing analysis, are presented and assessed through a user needs survey. In chapter 3, the six recovery categories and thirteen indicators identified in the literature review form a framework for the retrospective analysis of recovery in Thailand and Pakistan. A selection of results is presented to demonstrate the usefulness of remote sensing as a recovery monitoring tool. To assess its reliability, the results from the satellite image analysis are triangulated against narratives and datasets acquired on the ground. The next two chapters describe work done whilst providing real-time support to two humanitarian agencies operating in Port-au-Prince one-and-a-half years after the 2010 Haiti earthquake. Chapter 4 describes how geospatial tools were used to support a British Red Cross integrated reconstruction project for 500 households living in an informal settlement. The chapter describes how geospatial tools were used as a rapid assessment tool, and to support cadastral and enumeration mapping and the community participatory process. While previous chapters focus on the manual analysis of satellite imagery, chapter 5 reports how semi-automatic analyses of satellite imagery were used to support UN-Habitat by monitoring a planned camp and large-scale instances of spontaneous settlement. The conclusion to the thesis summarises the key lessons learnt from the retrospective analysis of recovery in Thailand and Pakistan and the real-time application in Haiti. Recommendations are then made on how to effectively use remote sensing in support of post-disaster recovery focussing on what to measure, when and how. Recognising that a mixed-method approach can best monitor recovery, recommendations are also made on how to integrate remote sensing with existing tools.
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Huang, Yanping. "Modelling land use change and agricultural performance in post-reform China using remotely sensed data and GIS." Thesis, University of Oxford, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.264570.
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Veal, Matthew Wayne. "ENHANCED GRAIN CROP YIELD MONITOR ACCURACY THROUGH SENSOR FUSION AND POST-PROCESSING ALGORITHMS." UKnowledge, 2006. http://uknowledge.uky.edu/gradschool_diss/249.
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Yield monitors have become an indispensable part of precision agriculture systemsbecause of their ability to measure the yield variability. Accurate yield monitor data availabilityis essential for the assessment of farm practices. The current technology of measuring grainyields is prone to errors that can be attributed to mass flow variations caused by the mechanismswithin a grain combine. Because of throughput variations, there are doubts regarding thecorrelation between the mass flow measurement and the actual grain volume produced at aspecific location. Another inaccuracy observed in yield monitor data can be attributed to inexactcut-widths values entered by the machine operator.To effectively address these yield monitor errors, two crop mass flow sensing deviceswere developed and used to correct yield monitor data. The two quantities associated with cropmaterial mass flow that were sensed were tension on the feeder housing drive chain and thehydraulic pressure on the threshing cylinder's variable speed drive. Both sensing approacheswere capable of detecting zero mass flow conditions better than the traditional grain mass flowsensor. The alternative sensors also operate without being adversely affected by materialtransport delays. The feeder housing-based sensor was more sensitive to variations in cropmaterial throughput than the hydraulic pressure sensor. Crop mass flow is not a surrogate forgrain mass flow because of a weak relationship (R2 andlt; 0.60) between the two quantities. The cropmass flow signal does denote the location and magnitude of material throughput variations intothe combine. This delineation was used to redistribute grain mass flow by aligning grain andcrop mass flow transitions using sensor fusion techniques. Significant improvements (?? = 0.05)in yield distribution profile were found after the correction was applied.To address the cut-width entry error, a GIS-based post-processing algorithm wasdeveloped to calculate the true harvest area for each yield monitor data point. Based on theresults of this method, a combine operator can introduce yield calculation errors of 15%. Whenthese two correction methods applied to yield monitor data, the result is yield maps withdramatically improved yield estimates and enhanced spatial accuracy.
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Holoviak, Brent Matthew. "Application of Ancillary Data In Post-Classification to Improve Forest Area Estimates In A Landsat TM Scene." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/34916.
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In order to produce a more current inventory of forest estimates along with change estimates, the Forest Inventory Analysis (FIA) program has moved to an annual system in which 20% of the permanent plots in a state are surveyed. The previous system sampled permanent plots in 10-year intervals by sampling states sequentially in a cycle (Wayman 2001, USDA FIA). The move to an annual assessment has introduced the use satellite technology to produce forest estimates. Wayman et al (2001) researched the effectiveness of satellite technology in relation to aerial photo-interpretation, finding the satellite method to do an adequate job, but reporting over-estimations of forest area. This research extends the satellite method a step further, introducing the use of ancillary data in post-classification.
The US Forest Service has well-defined definitions of forest and nonforest land-use in its (FIA) program. Using these definitions as parameters, post-classification techniques were developed to improve forest area estimates from the initial spectral classification.
A goal of the study was to determine the accuracy of using readily available ancillary data. US Census data, TIGER street files, and local tax parcel data were used. An Urban Mask was created based on population density to mask out Forested pixels in a classified image. Logistic Regression was used to see if population density, street density, and land value were good predictors of forest/nonforest pixels.
Research was also conducted on accuracy when using contiguity filters. The current filter used by the Virginia Department of Forestry (VDoF) was compared to functions available in ERDAS Imagine. These filters were applied as part of the post-classification techniques.
Results show there was no significant difference in map accuracies at the 95% confidence interval using the ancillary data with filters in a post-classification sort. However, the use of ancillary data had liabilities depending on the resolution of the data and its application in overlay.Master of Science
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Steinberg, Rebecca M. "Predicting Post-Mining Hydrologic Effects of Underground Coal Mines in Ohio throughMultivariate Statistical Analyses and GIS Tool Building." Ohio University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1555429886192267.
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Batres, Carlos A. "TRACING THE "ENIGMATIC" LATE POSTCLASSIC NAHUA-PIPIL (A.D. 1200-1500): ARCHAEOLOGICAL STUDY OF GUATEMALAN SOUTH PACIFIC COAST." OpenSIUC, 2009. https://opensiuc.lib.siu.edu/theses/136.
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This thesis addressed the Late Post-classic (A.D. 1200 - 1500) Nahua-Pipil of the central Pacific coast of Guatemala. It evaluated archaeological settlement plan data and ceramics in association with regional geography, and ethnohistorical accounts in conjunction with GIS tools for their analysis. The goal is to reconstruct Nahua-Pipil sociopolitical organization, testing the hypothesis that it was based on the Nahua altepetl system.
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Gilliland, Joshua M. "A Climatology of High-Wind Events Associated with Post-Tropical Cyclones in the United States." TopSCHOLAR®, 2011. http://digitalcommons.wku.edu/theses/1074.
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During 1951-2009, 47% of all tropical systems (TSs) within the Atlantic Basin transitioned to post-tropical (PTC) extratropical classification. These systems have shown the capability of producing hurricane-force winds and gusts for portions of the eastern United States. This study provides a climatological foundation for high-wind observations that were contributed from PTCs. In this study, 76 PTC systems were identified and tracked using six hourly observations from the National Hurricane Center’s HURDAT dataset. Mean wind radii buffers were calculated and used to determine the high-wind observations attributed by PTCs. High-wind climatology was developed by using hourly surface wind data from the National Climatic Data Center (NCDC) and deploying the current NWS high-wind criteria. For this study, the geography and climatology of PTCs and resultant high winds were analyzed using geographic information systems (GIS). Findings show that < 1% (270) of all high-winds events that occur within the U.S. were contributed from PTCs. The highest frequencies were found in three regions: Midwest, Mid-Atlantic, and New England. Due to the low number of high-wind events produced from PTCs, an adjusted wind scale was created by using standard deviations of sustained and gust observations. The goal of this study is determine the contribution of high winds from PTCs, with the aim of improving our understanding of the hazardous outcomes of such events.
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Griesbach, Christopher James. "Improving LiDAR Data Post-Processing Techniques for Archaeological Site Management and Analysis: A Case Study from Canaveral National Seashore Park." Scholar Commons, 2015. https://scholarcommons.usf.edu/etd/5491.
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Methods used to process raw Light Detection and Ranging (LiDAR) data can sometimes obscure the digital signatures indicative of an archaeological site. This thesis explains the negative effects that certain LiDAR data processing procedures can have on the preservation of an archaeological site. This thesis also presents methods for effectively integrating LiDAR with other forms of mapping data in a Geographic Information Systems (GIS) environment in order to improve LiDAR archaeological signatures by examining several pre-Columbian Native American shell middens located in Canaveral National Seashore Park (CANA).
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Agostini, Fantini Francesco, and Carbonell Javier Izaguirre. "GIS-Based approach to estimate the energy requirements of the post-harvest activities in Souss-Massa basin in Morocco." Thesis, KTH, Energiteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-249070.
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Over the last decades the Moroccan agriculture has passed through a complete transformation: due to the low workforce cost and its favourable climate, the sector has attracted the attentions of national and foreign investment and thus has expanded rapidly. Among the different productions, tomatoes proved to be one of the most profitable, generating 4.867 billion dirhams in 2016 from exports. In order to remain competitive and attractive, the sector needs to be constantly monitored and controlled: abuses of the environment and of available resources may affect or even compromise the future of the Moroccan agriculture. Energy in particular has a remarkable role and has to be analysed in order to quantify its impact over costs and environment. The aim of this study is to build a GIS-based model of tomato’s postharvest system and study the agriculture and energy nexus interactions in the Souss-Massa region. Post harvesting activities such as: Transportation, conditioning, packaging, storing and transformation of tomato, occurs within Souss-Massa’s geographical boundaries and have been the focus of in this study. Results of current system highlight the dominance of packaging activity as the main energy consumer with 77%, followed by storing, transportation and transformation with 14 %, 6% and 3% respectively. In terms of cost the transportation becomes the most relevant activity due to the cost of fuels and transport conditions. Energy costs and wastes in transportation represent 15% of the local revenues (9% Transportation, 5% Packaging and 1% Storing). Four different scenarios about the future situation have been implemented to measure the possible impact of changes in the different activities: Business as Usual (BAU), Transport Efficiency (TE), Waste Reduction (WR) and Renewable Penetration (RP). -3- In BAU current trends have been followed to forecast the total production, the export and the power generation. In TE trucks with bigger capacity have been implemented and in WR refrigeration is considered in every transport stage. Finally, in RP higher renewable penetration has been consideredI över ett decennium har en förändring skett i det marockanska jordbruket, kombinerat med låga arbetskostnader och landets gynnsamma klimat har sektorn fått stor uppmärksamhet vilket har resulterat i att både nationell och internationella investeringar och sektorn har därmed kraftigt expanderats. Jordbruksproduktionen som visat sig vara mest gynnsam är produktion av tomater, där export av varan har genererat 4,867 miljarder dirham. För att säkerställa en attraktiv och konkurrenskraftig produktion är konstant övervakning och kontinuerlig kontroll ett måste; missbruk av miljö och dess resurser kan ha betydande påverkan vilket på sikt kan kompromissa framtiden för det Marockanska jordbruket. Energi har en betydande roll i jordbruket och bör därmed analyseras för att förstå dess övergripande inverkan på kostnader och miljö. Syftet med denna studie är att bygga upp en GIS baserad modell över tomatprodukten efter skörd samt att studera relationen mellan energi- & jordbrukssektorn i Souss-Massa regionen. Efter skörd inkluderas följande aktiviteter: transport, konditionering, förpackning, förvaring, och transformering av tomater. Studiens geografiska systemgräns gäller området Souss-Massa. Resultatet av studien visar att den mest energikrävande processen är förpackning av tomater och står för totalt 77% av energikonsumtionen, därefter följer förvaring, transport och transformering av 15%, 6% och 3% respektive. Resultaten visar dessutom att transport är den mest kostsamma aktivitet i processen, detta på grund av höga kostnader för bränsle samt förutsättningar för transport. Energi- och avfallskostnader i transport representerar 15 % av lokala intäkter (9% transport, 5% förpackning och 1% lagring). Fyra framtidsscenarion utformades för att mäta den framtida inverkan hos de olika aktiviteterna: Business as Usual (BAU), Transporteffektivisering (TE), Avfallshantering (WR) och Förnybar energimix i jordbrukssektorn (RP). I BAU scenariot har nuvarande trender följts för att förutse totala produktionen, export och kraftproduktion. I TE scenariot har lastbilar större kapacitet jämfört med de andra scenariona och i WR är konditionering inkluderat i vardera transportsteg. Slutligen i RP har en förnybar energimix integrerats i systemet.
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Meenar, Md Mahbubur R. "FOOD JUSTICE IN POST-INDUSTRIAL US CITIES: THE ROLE OF NONPROFIT ORGANIZATIONS." Diss., Temple University Libraries, 2014. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/247409.
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GeographyPh.D.
The primary purposes of this dissertation were to (i) assess and identify post-industrial urban neighborhoods with food-insecure and vulnerable populations, and (ii) explore and analyze the role of nonprofit organizations (NPOs) in addressing place-based food insecurity. The study used mixed-methods, including qualitative GIS, statistical tests, surveys, interviews, and field observations. A food justice theoretical framework was used to develop a Place-Based Food Insecurity and Vulnerability Index (PFIVI), which factored together 33 variables to measure six indicators. The study applied this index in the City of Philadelphia and then examined three types of interventions that NPOs embark on - providing hunger relief, providing healthy and affordable food through the alternative food movement, and offering food-based programs and events tied with community capacity building efforts. Statistical relationships between PFIVI scores and NPO-driven programs showed spatial mismatch issues between the programs and community needs in some neighborhoods. This research also highlighted other limitations of these programs and the challenges that NPOs face both on- and above-the-ground. While the NPOs are trying hard to promote food justice through their mission statements, advocacy, outreach, and on-the-ground programs, the city may have only partially achieved this goal. A lot more needs to be done by strengthening organizational networks, strengthening social networks with community residents, and offering healthy but affordable food in disadvantaged neighborhoods, and NPOs alone should not bear these responsibilities.
Temple University--Theses
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Koohikamali, Mehrdad. "Assessment of Post-earthquake Building Damage Using High-resolution Satellite Images and LiDAR Data - a Case Study From Port-au-prince, Haiti." Thesis, University of North Texas, 2014. https://digital.library.unt.edu/ark:/67531/metadc700081/.
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When an earthquake happens, one of the most important tasks of disaster managers is to conduct damage assessment; this is mostly done from remotely sensed data. This study presents a new method for building detection and damage assessment using high-resolution satellite images and LiDAR data from Port-au-Prince, Haiti. A graph-cut method is used for building detection due to its advantages compared to traditional methods such as the Hough transform. Results of two methods are compared to understand how much our proposed technique is effective. Afterwards, sensitivity analysis is performed to show the effect of image resolution on the efficiency of our method. Results are in four groups. First: based on two criteria for sensitivity analysis, completeness and correctness, the more efficient method is graph-cut, and the final building mask layer is used for damage assessment. Next, building damage assessment is done using change detection technique from two images from period of before and after the earthquake. Third, to integrate LiDAR data and damage assessment, we showed there is a strong relationship between terrain roughness variables that are calculated using digital surface models. Finally, open street map and normalized digital surface model are used to detect possible road blockages. Results of detecting road blockages showed positive values of normalized digital surface model on the road centerline can represent blockages if we exclude other objects such as cars.
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Barr, Elaine Lewis. "Acoustic sampling considerations for bats in the post-white-nose syndrome landscape." Thesis, Virginia Tech, 2020. http://hdl.handle.net/10919/104232.
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Bat populations across North America are either facing new threats from white-nose syndrome (WNS) and wind energy development or have already experienced precipitous declines. Accordingly, researchers and managers need to know how to best monitor bats to document population and distribution changes, as well as where to look for persisting populations. Landscape-scale WNS impacts to summer bat populations are not well understood, and although acoustic monitoring is commonly used to monitor these populations, there is limited information about differences among acoustic detectors and the implications to managers thereof. My objectives were to model the relationship between WNS impact, influence of available hibernacula, and environmental factors for summer nightly presence of three WNS-affected bats and to compare how multiple models of acoustic detectors perform in terms of detection probability and nightly recorded bat activity. I collected acoustic data from 10 study areas across Virginia, West Virginia, Ohio and Kentucky to describe changes in nightly presence of WNS-affected bat species during summer 2017. During the same period of time, I compared five types of acoustic detectors at Fort Knox, Kentucky. My results show the potential efficacy of using a WNS impact-year metric to predict summer bat presence, and highlight which environmental variables are relevant for large-scale acoustic monitoring. Additionally, my findings suggest that each of the detector types tested would suffice for most research and monitoring activities, but standardization of detector type within the scope of a project or study should be encouraged.Master of Science
Bat populations across North America are either facing new threats from white-nose syndrome (WNS) and wind energy development or have already experienced devastating declines. Accordingly, wildlife biologists need to know how to best monitor bats to document population and distribution changes, as well as where to look for remaining populations. Landscape-scale WNS impacts to summer bat populations are not well understood, and although acoustic technology is commonly used to monitor these populations, there is limited information about differences among acoustic detectors and the implications to managers thereof. My objectives were to model the relationship between WNS impact, influence of available bat hibernation caves, and environmental factors for summer nightly presence of three WNS-affected bats and to compare how multiple models of acoustic detectors perform in terms of detection probability and nightly recorded bat activity. I collected acoustic data from 10 study areas across Virginia, West Virginia, Ohio and Kentucky to describe changes in nightly presence of WNS-affected bat species during summer 2017. During the same period of time, I compared five types of acoustic detectors at Fort Knox, Kentucky. My results show potential viability of a WNS impact-year metric to predict summer bat presence, and highlight which environmental variables are relevant for large-scale acoustic monitoring. Additionally, my findings suggest that each of the detector types tested would suit most research and monitoring activities, but standardization of detector type within the scope of a project or study should be encouraged.
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Buckler, Daniel C. "Post-Fire Forest Recovery on Sofa Mountain in Waterton Lakes National Park, Alberta, Canada." Youngstown State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1338325100.
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Baldwin, Brian. "The Role of Geographic Information Systems in Post-Disaster Neighborhood Recovery: Lessons from Hurricanes Katrina and Rita." ScholarWorks@UNO, 2010. http://scholarworks.uno.edu/td/1142.
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Through partnerships and collaborations with universities, non-profits, local government, and private foundations, neighborhood associations and residents have been using Public Participation Geographic Information Systems (PPGIS) as a tool for neighborhood recovery in post-Katrina and Rita New Orleans. The landfall of Hurricanes Katrina and Rita along the Gulf Coast Region changed the way that Geographic Information Systems (GIS) are used for Emergency Management and Response, PPGIS, and community recovery. This research explores GIS and PPGIS best practices through an evaluation of New Orleans, LA case studies and seeks to present solutions for the development of a post-disaster PPGIS for community recovery.
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O'Connor, Erin E. "Post-fire Vegetative Regrowth Associated with Mature Tree Stands and Topography on Sofa Mountain." Youngstown State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1432908700.
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Cai, Zipan. "Multitemporal Satellite Data for Monitoring Urbanization in Nanjing from 2001 to 2016." Thesis, KTH, Geoinformatik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-214036.
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Along with the increasing rate of urbanization takes place in the world, the population keeps shifting from rural to urban areas. China, as the country of the largest population, has the highest urban population growth in Asia, as well as the world. However, the urbanization in China, in turn, is leading to a lot of social issues which reshape the living environment and cultural fabric. A variety of these kinds of social issues emphasize the challenges regarding a healthy and sustainable urban growth particularly in the reasonable planning of urban land use and land cover features. Therefore, it is significant to establish a set of comprehensive urban sustainable development strategies to avoid detours in the urbanization process. Nowadays, faced with such as a series of the social phenomenon, the spatial and temporal technological means including Remote Sensing and Geographic Information System (GIS) can be used to help the city decision maker to make the right choices. The knowledge of land use and land cover changes in the rural and urban area assists in identifying urban growth rate and trend in both qualitative and quantitatively ways, which provides more basis for planning and designing a city in a more scientific and environmentally friendly way. This paper focuses on the urban sprawl analysis in Nanjing, Jiangsu, China that being analyzed by urban growth pattern monitoring during a study period. From 2001 to 2016, Nanjing Municipality has experienced a substantial increase in the urban area because of the growing population. In this paper, one optimal supervised classification with high accuracy which is Support Vector Machine (SVM) classifier was used to extract thematic features from multitemporal satellite data including Landsat 7 ETM+, Landsat 8, and Sentinel-2A MSI. It was interpreted to identify the existence of urban sprawl pattern based on the land use and land cover features in 2001, 2006, 2011, and 2016. Two different types of change detection analysis including post-classification comparison and change vector analysis (CVA) were performed to explore the detailed extent information of urban growth within the study region. A comparison study on these two change detection analysis methods was carried out by accuracy assessment. Based on the exploration of the change detection analysis combined with the current urban development actuality, some constructive recommendations and future research directions were given at last. By implementing the proposed methods, the urban land use and land cover changes were successfully captured. The results show there is a notable change in the urban or built-up land feature. Also, the urban area is increased by 610.98 km2 while the agricultural land area is decreased by 766.96 km2, which proved a land conversion among these land cover features in the study period. The urban area keeps growing in each particular study period while the growth rate value has a decreasing trend in the period of 2001 to 2016. Besides, both change detection techniques obtained the similar result of the distribution of urban expansion in the study area. According to the result images from two change detection methods, the expanded urban or built-up land in Nanjing distributes mainly in the surrounding area of the central city area, both side of Yangtze River, and Southwest area. The results of change detection accuracy assessment indicated the post-classification comparison has a higher overall accuracy 86.11% and a higher Kappa Coefficient 0.72 than CVA. The overall accuracy and Kappa Coefficient for CVA is 75.43% and 0.51 respectively. These results proved the strength of agreement between predicted and truth data is at ‘good’ level for post-classification comparison and ‘moderate’ for CVA. Also, the results further confirmed the expectation from previous studies that the empirical threshold determination of CVA always leads to relatively poor change detection accuracy. In general, the two change detection techniques are found to be effective and efficient in monitoring surface changes in the different class of land cover features within the study period. Nevertheless, they have their advantages and disadvantages on processing change detection analysis particularly for the topic of urban expansion.
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Liu, Yimei [Verfasser], Thomas Akademischer Betreuer] Wunderlich, Matthäus [Akademischer Betreuer] Schilcher, and Liqiu [Akademischer Betreuer] [Meng. "Distributed geo-services based on Wireless GIS : a case study for post-quake rescue information system / Yimei Liu. Gutachter: Thomas Wunderlich ; Matthäus Schilcher ; Liqiu Meng. Betreuer: Liqiu Meng." München : Universitätsbibliothek der TU München, 2011. http://d-nb.info/1014330742/34.
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Gungor, Haki Zeynep. "Assessment Of Social Vulnerability Using Geographic Information Systems: Pendik, Istanbul Case Study." Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/1252196/index.pdf.
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Natural hazards are the reality of today’
s world, which considerably affect people&
#8217
s living conditions. As they cannot be prevented, the basic precautions should be taken before the occurrence to protect people. At this point, the preparedness for any threat is really important, which does decrease destructive effects of the hazard for communities and shorten recovery interventions. In terms of preparedness, identification of vulnerable people in the community gives an important contribution for better planning in disaster management. In this respect, this thesis aims to develop a methodology in order to define vulnerable groups in terms of their social conditions for any possible hazard, with Geographic Information Systems (GIS) technology. Moreover, the thesis aims to find out an interrelation between hazards and vulnerability, to build awareness about identification of socially vulnerable groups in the pre- and post-disaster planning. A case study area is selected in earthquake-prone Pendik, Istanbul, in order to find the contribution of the assessment. A study is carried out to describe social vulnerability levels in the study area using GIS. Criterion standardization, weighting and combining are accomplished by multi criteria evaluation methods. These calculations are supported with five explorative spatial data analyses to understand global trends and spatial interactions of the study data. The objectivity of the assessment and the complicated structure of the study data are also discussed. The main outcomes of the methodology and its applications in the case study area show that, the southeast part of Pendik is socially vulnerable to any possible hazard.
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Sandu, Alexandra. "Les dynamiques urbaines post-socialistes en Europe centrale et orientale : continuités et discontinuités dans l'évolution morphologique et fonctionnelle." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSE2020.
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Les villes d’Europe centrale et orientale suscitent l’intérêt des chercheurs, car leur évolution a suivi des trajectoires particulières vu leur histoire complexe. Mais le plus souvent leurs transformations sont recensées à partir des changements politiques et socio-économiques et non pas du point de vue de l’évolution morphologique et fonctionnelle. Cette thèse propose une démarche d’analyse quantitative à la fois des changements morphologiques des villes d’Europe centrale et orientale avant et après l’effondrement de communisme, ainsi que des changements fonctionnels dans la période post-socialiste, les deux doublées par une analyse exploratoire de la capacité de résilience spatiale et socio-économique des villes à court et à long terme. Par conséquent, cette thèse vise à ajouter la dimension spatiale à l’analyse socio-économique et politique de la ville post-socialiste de l’Europe centrale et orientale, en questionnant les similarités et les dissimilarités qui les caractérisent. Nos résultats montrent un territoire d’Europe centrale et orientale assez hétérogène, avec des fractures ouest-est au niveau régional (dans l’ensemble du territoire), mais également au niveau national. La ville d’Europe centrale et orientale s’esquisse dans un modelé urbain conciliant l’héritage du passé, y compris l’héritage socialiste, avec les nouvelles demandes de l’économie de marché, ce qui se traduit spatialement par l’émergence d’une ville qui se rapproche du modèle de la ville d’Europe de l’Ouest, tout en restant différenteCities in Central and Eastern Europe are a subject of interest for researchers, as their evolution has followed particular trajectories in view of their complex history. However, often, the transformations of the cities of Central and Eastern European countries are analysed by taking into account only the political and socio-economic changes and not from the point of view of morphological and functional evolution. Thus, this thesis proposes a quantitative approach in what concerns the analysis of both the morphological changes of the cities of Central and Eastern Europe before and after the collapse of communism as well as the functional changes of the post-socialist period, both doubled by an exploratory analysis of spatial and socio-economic capacity of resilience of cities in the short and long term. Therefore, this thesis aims to add the spatial dimension to the socio-economic and political analysis of the post-socialist city of Central and Eastern Europe, by questioning the similarities and dissimilarities that characterize them. Our results show a rather heterogeneous territory of Central and Eastern Europe, with West-East fractures at the regional level, as well as at the national level. The city of Central and Eastern Europe is outlined as an urban model that seeks to reconcile the legacy of the past, including the socialist legacy, with the new demands of the market economy, which spatially translates into the emergence of a similar city, but in the same time different from that of Western Europe, which he seeks to match, fact that proves its complex context of evolution
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Taborelli, Pierre. "Les conditions géographiques et l'organisation spatiale du front de la Grande Guerre : application à l'évaluation environnementale post-conflit en Champagne-Ardenne (France)." Thesis, Reims, 2018. http://www.theses.fr/2018REIML004/document.
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L'objectif de la thèse, réalisée dans le cadre du programme IMPACT14-18 (2015-2018), est de cartographier et de mesurer les impacts environnementaux de la Première Guerre Mondiale en Champagne-Ardenne. Le projet propose une nouvelle approche de la Grande Guerre par une analyse spatiale des réseaux de défense sur 115 km de front (13 000 km de tranchées et de boyaux) réalisée sous SIG à partir des plans directeurs au 1/20 000 de 1918 des Groupes de Canevas de Tirs des Armées. Le traitement de la banque de données spatiales permet non seulement de déterminer le potentiel de « polémo-paysages » de la Grande Guerre mais aussi de comprendre les facteurs militaires et géographiques (géomorphologie, géologie, hydrographie) structurant les réseaux. Les morphologies associées (tranchées, boyaux, entonnoirs de mines, trous d’obus), intégralement nivelées en grande culture mais recoupées par l’approche archéologique, sont étudiées de manière sectorielle, sous forêt à l’aide du Lidar aéroporté pour déterminer leur taux de conservation, sous la commande des pratiques sylvicoles. L’application opérationnelle des résultats s’intègre dans l’évaluation environnementale et les problématiques territoriales post-conflit de la Grande Guerre (aléa « cavités », bombturbation, contamination des sols et des nappes souterraines) mais révèle également un potentiel de valorisation patrimonialeThe purpose of the thesis, carried out under the IMPACT14-18 program (2015-2018), is to map and measure the environmental impact of the First World War in Champagne-Ardenne. The project offers a new approach of the Great War by a spatial analysis of the defense networks on the 115 km of front (13 000 km of trenches and communication trenches) achieved under GIS from the 1/20 000 of 1918 trenches maps of the “Groupes de Canevas de Tirs des Armées”. The treatment of spatial database not only helps us to determine the potential of "Polemo Landscapes" of the Great War but also to understand the military and geographical factors (geomorphology, geology, hydrography) structuring the networks. Associated morphologies (trenches, communications trenches, mine craters, shells craters), fully leveled in the field but highlighted by the archaeological approach, are studied sectorally under the forest thanks to the airborne Lidar, in order to define their conservation rates, according to the silvicultural practices. The operational application of the results fits the environmental assessment and the post-conflict territorial issues of the Great War ("cavities" hazard, bombturbation, soil and groundwater contamination) but also reveals a potential for heritage enhancement
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Richardson, Paul D. "Pluton Zonation Unveiled by Gamma-ray Spectrometry and Magnetic Susceptibility; A Case Study of the Sheeprock Granite, Western, Utah." BYU ScholarsArchive, 2004. https://scholarsarchive.byu.edu/etd/209.
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A radiometric survey of the zoned 21 Ma, A-type Sheeprock granite, western Utah, combined with measurements of magnetic susceptibility and field observations were analyzed using a geographic information system. The intrusion spans 25 square km and is roughly eliptical in shape with its long axis trending northwest. Concentration maps (composed of more than 500 survey stations) of eU, eTh, texture, magnetic susceptibility, color, and joint density help to constrain magmatic and post-magmatic processes related to its chemical and physical zonation. Uranium ranges from 3.9 to 26.9 ppm (mean 12.7) and thorium from 1.7 to 125.7 ppm (mean 45.5). Similarities in spatial patterns and near normal distributions of U and Th imply minimal remobilization and secondary equilibrium of U. Relatively high magnetic susceptibility (6 to 12*10^-3 SI units), low eU and eTh, and limited whole rock chemical anayses show the southeastern part of the pluton is more mafic and most likely formed as an early cumulate. Dominant textures are porphyritic with a fine-grained matrix along the northeastern margin, coarsening to a medium-grained matrix along the southwestern margin. This transition from fine to medium-grained matrix textures is believed to be a preserved solidification front that had migrated from the roof and walls inward during cooling. Late stage magma mixing is evidenced by a string of mafic enclaves along the axis of the pluton near this solidification front. eU and eTh generally increase toward the finer-grained northeastern margin of the pluton. This has been interpreted to be the primary result of fractionation of U and Th into monazite and thorite. As mafic cumulates formed along the northeastern margin residual liquids were displaced inward. This depleted the more evolved parts of the pluton in U and Th. Beryl, a distinquishing characteristic of the most evolved portions of the pluton, is concentrated in two areas along the central axis of the intrusion. The intrusion is a cumulative of three magmatic phases, the second of which crystallized from the margins inward. Joint spacing is a major factor in controlling post-magmatic processes. The pluton has a higher density of joints (10 cm apart) near the upper margins, and fewer joints (> 1 meter apart) at lower elevations. Differential cooling and magma pressures are believed to have controlled the varying joint densities. Increased alteration, oxidation, and red-staining are more prevalent in areas of higher joint density. Magnetic susceptibility is bimodal. The high mode (5.4*10^-3 SI) is on the low end of magnetite-series granites and occurs most often in the white granite. The low mode (0.07*10^-3 SI) implies significant post-magmatic oxidation and the destruction of magnetite and correlates to the red granite. Truncated chemical and textural patterns along the pluton's northwestern margin support evidence for range front normal faulting.
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Madsen, Matthew D. "Influence of Soil Water Repellency on Post-fire Revegetation Success and Management Techniques to Improve Establishment of Desired Species." BYU ScholarsArchive, 2009. https://scholarsarchive.byu.edu/etd/1994.
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The influence of soil water repellency (WR) on vegetation recovery after a fire is poorly understood. This dissertation presents strategies to broaden opportunities for enhanced post-fire rangeland restoration and monitoring of burned piñon and juniper (P-J) woodlands by: 1) mapping the extent and severity of critical and subcritical WR, 2) determining the influence of WR on soil ecohydrologic properties and revegetation success, and 3) evaluating the suitability of a wetting agent composed of alkylpolyglycoside-ethylene oxide/propylene oxide block copolymers as a post-fire restoration tool for ameliorating the effects of soil WR and increasing seedling establishment. Results indicate that: • Post-fire patterns of soil WR were highly correlated to pre-fire P-J woodland canopy structure. Critical soil WR levels occurred under burned tree canopies while sub-critical WR extended out to approximately two times the canopy radius. At sites where critical soil WR was present, infiltration rate, soil moisture, and vegetation cover were significantly less than at non-hydrophobic sites. These parameters were also reduced in soils with subcritical WR relative to non-hydrophobic soils (albeit to a lesser extent). Aerial photography coupled with feature extraction software and geographic information systems (GIS) proved to be an effective tool for mapping P-J cover and density, and for scaling-up field surveys of soil WR to the fire boundary scale. • Soil WR impairs seed germination and seedling establishment by decreasing soil moisture availability by reducing infiltration, decreasing soil moisture storage capacity, and disconnecting soil surface layers from underlying moisture reserves. Consequently, soil WR appears to be acting as a temporal ecological threshold by impairing establishment of desired species within the first few years after a fire. • Wetting agents can significantly improve ecohydrologic properties required for plant growth by overcoming soil WR; thus, increasing the amount and duration of available water for seed germination and seedling establishment. Success of this technology appears to be the result of the wetting agent increasing soil moisture amount and availability by 1) improving soil infiltration and water holding capacity; and 2) allowing seedling roots to connect to underling soil moisture reserves.
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Joncheray, Mathilde. "Vivre la guerre, construire la paix : Conflits et recompositions territoriales post-conflit en République du Congo (Pays du Niari)." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM3104.
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Les guerres sont d’importants facteurs de recompositions territoriales. Les territoires des « Pays du Niari », région créée par le politique, ont une place particulière dans l’histoire des conflits au Congo et celle-ci conditionne leur reconstruction. Après 10 ans de guerres, la région a du mal à se remettre, et se trouve au cœur d’enjeux socio-économiques, politiques et identitaires à différentes échelles.Cette thèse étudie d’une part les conflits, procédant à une géohistoire méthodique d’une région et de populations occultés par les acteurs nationaux et internationaux. Elle étudie d’autre part la façon dont les différents acteurs s’approprient la notion de post-conflit et les répercussions territoriales des actions entreprises. Cela amène enfin à faire état du hiatus entre actions de reconstructions et besoins des populations et des territoires, visibles à travers des territoires et des temporalités fragmentésWars are major factors in territorial reorganisation. The territories of the “Pays du Niari”, region created by politicians, have a particular/specific place in the history of conflicts in Congo and the former influences their reconstruction. After 10 years of war, the region finds it difficult to recover, and finds itself in the middle of socio-economic, political and identity issues at different levels.This thesis studies, on the one hand, the conflicts leading to a methodical history-geography change of a region and populations put aside by national and international decision makers. It studies, on the other hand, how the different actors make theirs the notion of the post conflict and the territorial repercussions of the actions undertaken. This finally leads us to put forward the hiatus between reconstruction actions and the needs of the populations and the territories, clearly visible through the fragmented territories and timeframes
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Yesuf, Hassen M., K. Decker French, S. M. Faber, and David C. Koo. "Molecular gas during the post-starburst phase: low gas fractions in green-valley Seyfert post-starburst galaxies." OXFORD UNIV PRESS, 2017. http://hdl.handle.net/10150/625482.
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Post-starbursts (PSBs) are candidate for rapidly transitioning from starbursting to quiescent galaxies. We study the molecular gas evolution of PSBs at z similar to 0.03-0.2. We undertook new CO (2-1) observations of 22 Seyfert PSB candidates using the Arizona Radio Observatory Submillimeter Telescope. This sample complements previous samples of PSBs by including green-valley PSBs with Seyfert-like emission, allowing us to analyse for the first time the molecular gas properties of 116 PSBs with a variety of AGN properties. The distribution of molecular gas to stellar mass fractions in PSBs is significantly different from normal star-forming galaxies in the CO Legacy Database (COLD) GASS survey. The combined samples of PSBs with Seyfert-like emission line ratios have a gas fraction distribution that is even more significantly different and is broader (similar to 0.03-0.3). Most of them have lower gas fractions than normal star-forming galaxies. We find a highly significant correlation between the WISE 12 and 4.6 mu m flux ratios and molecular gas fractions in both PSBs and normal galaxies. We detect molecular gas in 27 per cent of our Seyfert PSBs. Taking into account the upper limits, the mean and the dispersion of the distribution of the gas fraction in our Seyfert PSB sample are much smaller (mu = 0.025, sigma = 0.018) than previous samples of Seyfert PSBs or PSBs in general (mu similar to 0.1-0.2, sigma similar to 0.1-0.2).
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Monk, Lorna Sophia. "Post-anoxic injury in higher plants." Thesis, University of St Andrews, 1987. http://hdl.handle.net/10023/14415.
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The perennating organ, the rhizome, was chosen for examination of response to anoxia in monocotyledonous species known to differ in tolerance of flooding. Survival of prolonged anoxia was monitored in the wetland species (Acorus calamus, Iris pseudacorus. Phragmites australis, Schoenoplectus lacustris and Typha latifolia), and the dryland species (Iris germanica). Fermentation capacity was estimated in the anoxic and post-anoxic phases together with ethanol and lactate accumulation. Under N2 accumulation of ethanol took place in all species; lactic fermentation was of less importance. There was a steady-state condition of low ethanol accumulation in the wetland species, where an apparent equilibrium of production and elimination from rhizome tissue was reached. In contrast, the dryland species showed a continuous increase in ethanol accumulation during oxygen deprivation. Catalase and superoxide dismutase activities were measured during the post-anoxic recovery phase in their role as enzymatic defences against oxygen toxicity. In rhizomes of the anoxia tolerant species A. calamus. S. lacustris and I. pseudacorus, no changes in catalase activity were observed. However, the relatively anoxia intolerant Glyceria maxima, Juncus effusus and I.germanica exhibited significant increases in catalase activity. To investigate whether catalase (acting in its 'peroxidatic' mode) was perhaps here involved in an ethanol oxidation reaction, anaerobic rhizomes of G.maxima were exposed to ethanol vapour: considerable increases in catalase activity were recorded. It is proposed that acetaldehyde thus produced may be a source of post-anoxic injury. Superoxide dismutase activity in I.pseudacorus rhizomes rose significantly during anoxia, while small increases were found in the less anoxia tolerant I.germanica and a drop in activity was recorded in G.maxima. It is suggested that I.pseudacorus may be less susceptible to post-anoxic injury by means of oxygen toxicity, while in the other species oxidative damage on return to air may contribute to anoxia intolerance.
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Nystrand, Ove. "Post-dispersal predation on conifer seeds and juvenile seedlings in boreal forest /." Umeå : Swedish University of Agricultural Sciences (Sveriges lantbruksuniv.), 1998. http://epsilon.slu.se/avh/1998/91-576-5345-3.gif.
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Prashanth, Prakash. "Post-combustion emissions control for aero-gas turbine engines." Thesis, Massachusetts Institute of Technology, 2018. https://hdl.handle.net/1721.1/122402.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Aeronautics and Astronautics, 2018Cataloged from PDF version of thesis.
Includes bibliographical references (pages 47-50).
Aviation NO[subscript x] emissions have an impact on air quality and climate change, where the latter is magnified due to the higher sensitivity of the upper troposphere and lower stratosphere. In the aviation industry, efforts to increase the efficiency of propulsion systems are giving rise to higher overall pressure ratios which results in higher NO[subscript x] emissions due to increased combustion temperatures. This thesis identifies that the trend towards smaller engine cores (gas generators) that are power dense and contribute little to the thrust output presents new opportunities for emissions control that were previously unthinkable when the core exhaust stream contributed significant thrust. This thesis proposes and assesses selective catalytic reduction (SCR), which is a post-combustion emissions control method used in ground-based sources such as power generation and heavy-duty diesel engines, for use in aero-gas turbines.
The SCR system increases aircraft weight and introduces a pressure drop in the core stream. The effects of these are evaluated using representative engine cycle models provided by a major aero-gas turbine manufacturer. This thesis finds that employing an ammonia-based SCR can achieve close to 95% reduction in NO[subscript x] emissions for ~0.4% increase in block fuel burn. The large size of the catalyst needs to be housed in the body of the aircraft and hence would be suitable for future designs where the engine core is also within the fuselage, such as would be possible with turbo-electric or hybrid-electric designs. The performance of the post-combustion emissions control is shown to improve for smaller core engines in new aircraft in the NASA N+3 time-line (2030-2035), suggesting the potential to further decrease the cost of the ~95% NO[subscript x] reduction to below ~0.4% fuel burn.
Using a global chemistry and transport model (GEOS-Chem) this thesis estimates that using ultra-low sulfur (<15 ppm fuel sulfur content) in tandem with post-combustion emissions control results in a ~92% reduction in annual average population exposure to PM₂.₅ and a ~95% reduction in population exposure to ozone. This averts approximately 93% of the air pollution impact of aviation.
by Prakash Prashanth.
S.M.
S.M. Massachusetts Institute of Technology, Department of Aeronautics and Astronautics
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Spencer, A. "Gas turbine combustor port flows." Thesis, Loughborough University, 1998. https://dspace.lboro.ac.uk/2134/6883.
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Competitive pressure and stringent emissions legislation have placed an urgent demand on research to improve our understanding of the gas turbine combustor flow field. Flow through the air admission ports of a combustor plays an essential role in determining the internal flow patterns on which many features of combustor performance depend. This thesis explains how a combination of experimental and computational research has helped improve our understanding, and ability to predict, the flow characteristics of jets entering a combustor. The experiments focused on a simplified generic geometry of a combustor port system. Two concentric tubes, with ports introduced into the inner tube's wall, allowed a set of radially impinging jets to be formed within the inner tube. By investigating the flow with LDA instrumentation and flow visualisation methods a quantitative and qualitative picture of the mean and turbulent flow fields has been constructed. Data were collected from the annulus, port and core regions. These data provide suitable validation information for computational models, allow improved understanding of the detailed flow physics and provide the global performance parameters used traditionally by combustor designers. Computational work focused on improving the port representation within CFD models. This work looked at the effect of increasing the grid refinement, and improving the geometrical representation of the port. The desire to model realistic port features led to the development of a stand-alone port modelling module. Comparing calculations of plain-circular ports to those for more realistic chuted port geometry, for example, showed that isothermal modelling methods were able to predict the expected changes to the global parameters measured. Moreover, these effects are seen to have significant consequences on the predicted combustor core flow field.
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Bolaños, Moya Jorge Mario. "Post-partum reproductive performance of Zebu (Bos indicus) cows in the humid tropics /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 1997. http://epsilon.slu.se/avh/1997/91-576-5406-9.gif.
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Divak, Martin. "Simulated SAR with GIS data and pose estimation using affine projection." Thesis, Luleå tekniska universitet, Institutionen för system- och rymdteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-66303.
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Pilots or autonomous aircraft need to know where they are in relation to the environment. On board aircraft there are inertial sensors that are prone to drift which requires corrections by referencing against known items, places, or signals. One such method of referencing is with global navigation satellite systems, and others, that are highlighted in this work, are based on using visual sensors. In particular the use of Synthetic Aperture Radar is emerging as a viable alternative. To use radar images in qualitative or quantitative analysis they must be registered with geographical information. Position data on an aircraft or spacecraft is not sufficient to determine with certainty what or where it is one is looking at in a radar image without referencing other images over the same area. It is demonstrated in this thesis that a digital elevation model can be split up and classified into different types of radar scatterers. Different parts of the terrain yielding different types of echoes increases the amount of radar specific characteristics in simulated reference images. This work also presents an interpretation of the imaging geometry of SAR such that existing methods in Computer Vision may be used to estimate the position from which a radar image has been taken. This is a direct image matching without requiring registration that is necessary for other proposals of SAR-based navigation solutions. By determination of position continuously from radar images, aircraft could navigate independently of day light, weather, and satellite data.
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Linga, Praveen. "Separation of carbon dioxide from flue gas (post-combustion capture) via gas hydrate crystallization." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/6930.
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This thesis examines the prospect of employing hydrate crystallization in a gas/liquid stirred vessel for separation of carbon dioxide (CO₂) from a flue gas mixture. A treated flue gas mixture contains CO₂, O₂ and N₂. Because O₂ and N₂ form hydrate at approximately same pressure-temperature conditions a model gas mixture to work with consists of 17 mol % CO₂ and 83 mol % N₂.
Gas hydrates were formed in a 323 cm³ vessel at 273.7 K and constant pressures. The data enabled us to propose a process based on three hydrate stages coupled with a membrane separation stage. Two metrics, CO₂ recovery and separation factor were introduced to evaluate the efficiency of the process. The operating pressures were found to be 10, 5 and 2.5 MPa for the three stages. The high operating pressure required for the first stage necessitated the use of an additive to lower the pressure. Tetrahydrofuran (THF) was chosen and relevant thermodynamic and kinetic data were obtained and reported. The efficiency of the separation was also determined. It was concluded that a stream containing 96% CO₂ can be obtained from of a medium-pressure process consisting of three hydrate stages. The three stages operate at 2.5 MPa and 273.75 K without compromising the separation efficiency obtained without the addition of THF.
A new apparatus was designed and built to demonstrate the hydrate process at a larger scale. The results showed an improvement in the kinetics and the separation efficiency. Finally, the kinetics of the hydrate crystallization were also studied using a fixed bed of silica sand particles and the results were compared with those obtained in the gas/liquid systems. The gas uptake was found to be significantly higher for the systems involving water dispersed in silica sand.
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Niu, Jing. "Desalination of Produced Water via Gas Hydrate Formation and Post Treatment." Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/76822.
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This study presents a two-step desalination process, in which produced water is cleaned by forming gas hydrate in it and subsequently dewatering the hydrate to remove the residual produced water trapped in between the hydrate crystals. All experiments were performed with pressure in the range of 450 to 800psi and temperature in the range of -1 to 1°C using CO? as guest molecule for the hydrate crystals. The experiments were conducted using artificial produced waters containing different amounts of NaCl, CaCl₂ and MgCl₂ at varying temperature (T) and pressure (P). The results are presented as functions of %Reduction of difference chemical elements, CO? requirements and applied T and P conditions.
The impact of dewatering techniques, including centrifuge and filtration process, on gas hydrate solid product is studied. The results showed that over 99% of dissolved NaCl and MgCl2 can be removed from artificial saline water in laboratory experiments. This was achieved in a process involving a single-stage hydrate formation step, followed by a single-step solid-liquid separation (or dewatering). The results also show that the %Reduction (percentage of the concentration decrease) of artificial produced water increases with centrifugation time and rotational speed (rpm). The %Reduction was increased considerably after hydrate crystals were crushed and filtered, indicating that the artificial process water was entrapped in between the hydrate crystals. It was found also that the finer the particle size, the higher the extent of salt removal. In general, filtration was a better than centrifugation for the removal of TDS (Total Dissolved Solids).Master of Science
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Zhang, Miao. "Defects in ZnO nanoparticles obtained by gas-phase syntheses." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066259.
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L’attribution des signatures spectrales liées aux défauts dans l’oxyde de zinc fait encore l’objet de controverses. Ceci est probablement dû à la grande variété de défauts possibles, à l’incertitude de leur niveau d’énergie ainsi que leur énergie de formation dans la bande interdite. De plus, l’imprécision concernant les conditions de mesures et la possible présence d’impuretés inhérentes à certaines méthodes de synthèse peuvent souvent mener à des interprétations erronées. Le but de ce travail de thèse est donc d’identifier les défauts intrinsèques naturellement présents dans du ZnO fraîchement préparé ou bien formés via différents types de traitements post-synthèse. Pour atteindre ce but, notre stratégie fut (i) de préparer des nanoparticules modèles de ZnO en utilisant deux types de synthèses en phase vapeur (Combustion et CVS) (ii) de combiner des mesures in situ de photoluminescence (PL) et de RPE, également associées à des spectroscopies complémentaires (Raman, UV visible, FTIR) de façon à révéler, attribuer les défauts et discuter leur comportement selon les conditions de synthèses et de traitements post-synthèse et (iii) de révéler la réactivité des surfaces défectueuses de nos échantillons de ZnO en étudiant leur interaction avec des molécules d’eau ou de 2-méthyl-3-butyn-2-ol (MBOH). Nous avons ainsi observé que VO2+ et Zni+ sont les défauts natifs prédominants dans tous les échantillons fraîchement préparés de ZnO, dans des quantités relatives dépendant de la pression partielle d’oxygène utilisée lors de la synthèse. Les lacunes neutres d’oxygène (VO0) ont également été détectées dans le cas des préparations effectuées dans des conditions particulièrement riches en zinc. VO+ peut se former dans le ZnO smoke après post-traitement (recuit sous vide ou sous vapeur de zinc), la formation d’électrons associée participant à la réduction de Zni+ en Zn0. Au contraire, calciner sous O2 mène à des processus opposés, voire, sous excès d’O2, à la formation de défaut de type Oi. La dissociation de l’eau sur des surfaces préalablement calcinées sous vide mène au remplissage de VO+ et à la réduction de Zn2+ en Zn+. Des tests catalytiques de conversion du MBOH ont montré que de tels processus redox, contrôlés par les conditions de prétraitement, affectent la réactivité de surface de nos matériauxBy far, the assignment of defects-related spectroscopic features of zinc oxide is still a matter of great controversy. This is probably due to the variety of possible defects in ZnO as well as to their still uncertain formation energies and positions within the band gap. Uncontrolled measurement conditions and impurities related to some synthesis methods can additionally mislead interpretations. The aim of this work is to identify the intrinsic native defects in pure ZnO or formed upon different kind of post-synthesis treatments. To fulfill this goal our strategy was to: i) prepare model zinc oxide nanoparticles using two different vapor-phase synthesis techniques (Combustion and CVS) ii) identify, assign and discuss the occurrence of the defects in line with the synthesis and post treatments conditions by combining in situ PL and EPR measurements together with other complementary spectroscopies (Raman, UV vis, FTIR) and iii) reveal the surface reactivity of defective ZnO samples by studying the interaction with water or 2-methyl-3-butyn-2-ol (MBOH). We observed that in all as-synthesized ZnO samples VO2+ and Zni+ are the predominant native defects with relative amounts depending on the partial pressure of oxygen used during the synthesis. Neutral oxygen vacancies (VO0) are additionally detected in samples prepared in conditions particularly rich in zinc. The formation of Vo+ is demonstrated in ZnO smoke upon post treatment (annealing in high vacuum or zinc vapor) while the associated electron release is shown to participate to the reduction of Zni+ into Zn0. On the contrary, annealing in oxygen leads to reverse processes while if used in an excess, to creation of Oi-related defects. Dissociation of water on vacuum annealed surface leads to the filling up of VO+, and reduction of Zn2+ into Zn+. Such redox processes controlled by the pretreatment conditions affect the surface reactivity through the change of the acid base balance, as revealed by MBOH conversion catalytic tests
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Herraiz, Palomino Laura. "Selective exhaust gas recirculation in combined cycle gas turbine power plants with post-combustion carbon capture." Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/23460.
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Selective Exhaust Gas Recirculation (S-EGR) consists of selectively transferring CO2 from the exhaust gas stream of a gas-fired power plant into the air stream entering the gas turbine compressor. Unlike in “non-selective” Exhaust Gas Recirculation (EGR) technology, recirculation of, principally, nitrogen does not occur, and the gas turbine still operates with a large excess of air. Two configurations are proposed: one with the CO2 transfer system operating in parallel to the post-combustion carbon capture (PCC) unit; the other with the CO2 transfer system operating downstream of, and in series to, the PCC unit. S-EGR allows for higher CO2 concentrations in the flue gas of approximately 13-14 vol%, compared to 6.6 vol% with EGR at 35% recirculation ratio. The oxygen levels in the combustor are approximately 19 vol%, well above the minimum limit of 16 vol% with 35% EGR reported in literature. At these operating conditions, process model simulations show that the current class of gas turbine engines can operate without a significant deviation in the compressor and the turbine performance from the design conditions. Compressor inlet temperature and CO2 concentration in the working fluid are critical parameters in the assessment of the effect on the gas turbine net power output and efficiency. A higher turbine exhaust temperature allows the generation of additional steam which results in a marginal increase in the combined cycle net power output of 5% and 2% in the investigated configurations with S-EGR in parallel and S-EGR in series, respectively. With aqueous monoethanolamine scrubbing technology, S-EGR leads to operation and cost benefits. S-EGR in parallel operating at 70% recirculation, 97% selective CO2 transfer efficiency and 96% PCC efficiency results in a reduction of 46% in packing volume and 5% in specific reboiler duty, compared to air-based combustion CCGT with PCC, and of 10% in packing volume and 2% in specific reboiler duty, compared to 35% EGR. S-EGR in series operating at 95% selective CO2 transfer efficiency and 32% PCC efficiency results in a reduction of 64% in packing volume and 7% in specific reboiler duty, compared to air-based, and of 40% in packing volume and 4% in specific reboiler duty, compared to 35% EGR. An analysis of key performance indicators for selective CO2 transfer proposes physical adsorption in rotary wheel systems as an alternative to selective CO2 membrane systems. A conceptual design assessment with two commercially available adsorbent materials, activated carbon and Zeolite X13, shows that it is possible to regenerate the adsorbent with air at near ambient temperature and pressure. Yet, a significant step change in adsorbent materials is necessary to design rotary adsorption systems with dimensions comparable to the largest rotary gas/gas heat exchanger used in coal-fired power plants, i.e. approximately 24 m diameter and 2 m height. An optimisation study provides guidelines on the equilibrium parameters for the development of materials. Finally, a technical feasibility study of configuration options with rotary gas/gas heat exchangers shows that cooling water demand around the post-combustion CO2 capture system can be drastically reduced using dry cooling systems where gas/gas heat exchangers use ambient air as the cooling fluid. Hybrid cooling configurations reduce cooling and process water demand in the direct contact cooler of a wet cooling system by 67% and 35% respectively, and dry cooling configurations eliminate the use of process and cooling water and achieve adequate gas temperature entering the absorber.
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Xu, Heng. "Post-Synthetic Modification of Metal-Organic Frameworks by Solid-Gas Ozonolysis." Doctoral thesis, Universitat Autònoma de Barcelona, 2019. http://hdl.handle.net/10803/667135.
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Aquesta Tesi doctoral està dedicada a la investigació i l’estudi de l’ozonòlisi en fase solid-gas com un mètode ràpid, simple i versàtil per a la modificació post-sintètica de xarxes metalorgàniques (MOFs).
El primer Capítol inclou una breu introducció a l’origen dels MOFs i els conceptes per al disseny i síntesi de materials porosos. Després, fem èmfasi a les actuals metodologies utilitzades en les modificacions post-sintètiques de MOFs il·lustrant els principals avenços i exemples, amb l’objectiu de centrar al lector en el context d’aquesta Tesi. També s’hi expliquen les principals aplicacions de MOFs funcionalitzats post-sintèticament.
En el Capítol 2 s’hi exposen els objectius generals i específics d’aquesta Tesi.
En el Capítol 3 es desenvolupa la nova metodologia per a realitzar funcionalitzacions post-sintètiques de MOFs basades en l’ozonòlisi sòlid-gas. Els anells ozònids generats s’identifiquen per ressonància magnètica nuclear (RMN). Cal remarcar que aquest nou mètode s’ha demostrat mitjançant transformacions dins d’un mateix cristall, com s’ha confirmat per difracció de raigs X de monocristall conjuntament amb càlculs de teoria del funcional de la densitat (DFT). Finalment, la disposició de la funcionalitat ozònid és demostrada mitjançant un tractament selectiu posterior.
En el Capítol 4 s’estén l’ús de l’ozonòlisi sòlid-gas per a la modificació post-sintètica de la porositat de MOFs. Demostrem que, a través de la selecció de MOFs Zr-fcu amb mescla de lligands que consisteixen en parelles on un dels lligands conté enllaços olefina capaços de ser trencats per ozonòlisi i l’altre lligand és resistent a l’ozó, podem realitzar el trencament selectiu dels lligands mitjançant l’ozonòlisi per aconseguir la fusió de microporus en mesoporus en la mateixa estructura del MOF. Així, els MOFs mesoporosos es generen eliminant els fragments de lligand a través de rentats o sublimació, com ho evidencien les seves noves propietats d’adsorció.This present PhD Thesis has been dedicated to the exploration and study the solid-gas phase ozonolysis as a quick, simple and versatile method for post-synthetic modification of metal-organic frameworks (MOFs). In the first Chapter, a brief introduction to the origin of MOFs is given, followed by typical concepts for design and synthesis of the porous materials. We then pay special attention to the current methodologies that used for post-synthesic modifications of MOFs with state-of-the-art advancements and selected examples, aiming to place the reader in the context of the thesis. Additionally, the main applications of post-synthetically functionalized MOFs are provided. In Chapter 2, the general and specific objectives of the Thesis are introduced. In Chapter 3, we develop a new post-synthetic methodology for functionalization of MOFs based on the solid-gas ozonolysis. The generated ozonide rings are identified by nuclear magnetic resonance (NMR) technique. Moreover, the generality of this method has been proven by a single-crystal-to-single-crystal transformation, as confirmed by single-crystal X-Ray diffraction together with density functional theory (DFT) calculation. Finally, the amenability of ozonide functionality is demonstrated by selectively workup treatment. Chapter 4 extends the use of the solid-gas ozonolysis to post-synthetic modification of MOF porosity. We show that, by carefully selecting mixed-ligand Zr-fcu-MOFs based on organic ligand pairs in which one ligand has ozone-cleavable olefin bonds and the other ligand is ozone-resistant, we were able to selectively break the cleavable ligand via ozonolysis to trigger fusion of micropores into mesopores within MOF framework. Thus, the mesoporous MOFs are subsequently created through removal of ligand fragments by washing or sublimation, as evidenced by their distinct gas sorption properties.
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Bekana, Merga. "Clinical, ultrasonographic, bacteriological and hormonal studies in post-partum cows with particular emphasis on retained fetal membranes /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 1996. http://epsilon.slu.se/avh/1996/91-576-5223-6.gif.
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Liu, Ran. "Synthesis and Characterization of Novel Polybenzimidazoles and Post-modifications for Membrane Separation Applications." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/96200.
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Polybenzimidazoles, a class of aromatic heterocyclic polymers, are well known due to their remarkable thermal stability, mechanical properties and chemical resistance which are often required in extreme operation conditions. Because of these properties, polybenzimidazoles are excellent candidates in various application areas including proton exchange membrane fuel cells, gas separation membranes, reverse osmosis and nanofiltration, and high performance coatings. The following studies are focused on the synthesis, characterization and related properties of polybenzimidazoles and polybenzimidazole based materials.
A novel sulfonyl-containing tetraamino-substituted monomer (3,3',4,4'-tetraaminodiphenylsulfone) was synthesized and polymerized with three different diacid monomers to make polybenzimidazoles. The new monomer synthesis route with reduced steps relative to the existing literature method increased the overall yield by a factor of three. The sulfonyl-containing polybenzimidazoles have enhanced solubilities in common organic solvents including dimthylsulfoxide, dimethylacetamide and N-methyl-2-pyrrolidone in comparison with the commercial polybenzimidazole, Celazole ®, poly(2,2'-(m-phenylene)-5,5'-bibenzimidazole). The improvements in solubility are attributed to the introduction of polar sulfonyl linking moiety in the monomer. Remarkable thermal stabilities (high Tg, > 428 oC) were demonstrated through Dynamic Mechanical Analysis (DMA) and Thermogravimetric Analysis (TGA). A well designed film casting process was investigated and established. Polybenzimidazoles were
fabricated into transparent thin films (20-30 μm thick) for gas transport measurements. These novel polybenzimidazole films exhibited extraordinary gas separation properties, especially for H2/CO2 separation.
There is a trade-off relationship between gas permeability and selectivity through dense, non-porous polymer membranes that was discovered by Robeson in 1991. The ultimate goal for developing gas separation membranes is to improve both permeability and selectivity simultaneously. Gas permeability is related to the free volume between polymer chains. In order to improve gas permeability, we hypothesized a concept that increasing free volume could be achieved by thermally degrading sacrificial components and volatilizing their byproducts from a glassy matrix. Volatile components were introduced into the films to preoccupy the spaces between polymer chains. Once they were degraded and removed through the thermal treatment, it was hypothesized that the preoccupied spaces would remain empty due to the glassy nature of the matrix at the heat treatment temperature, thus resulting in more free volume. Two post- modification strategies including grafting and blending were utilized to incorporate the volatile components, poly(propylene oxide) and poly(ethylene oxide). Post-modified polybenzimidazole films impressively showed significant enhancements in both gas permeability and selectivity for H2/CO2 separation. The H2 permeability of the post-modified TADPS-OBA polybenzimidazole increased from 3.1-6.2 Barrers to 5.2-7.5 Barrers (up to 66% increase). The selectivity for H2/CO2 increased from 7.5-10.5 to 10.1-13.0 (up to 33% increase). The study on the potential effects of water vapor on the separation performance of PBI membranes was discussed in the appendix.Ph. D.
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Song, Zhili Jack. "Modeling of Gas Flows in Steelmaking Decarburization Processes." Doctoral thesis, KTH, Tillämpad processmetallurgi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-128541.
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The purpose of the current study is to increase the understanding of different steelmaking processes at the decarburization stages by use of mathematical modeling. More specifically, two De-Laval nozzles from a VOD (Vaccum Oxygen Decarburization) process, which is used for producing stainless steels with ultra-low carbon grades, was investigated for different vessel pressures. Moreover, the post combustion phenomena in a BOF or LD (Linz-Donawitz) process as well as an AOD (Argon Oxygen Decarburization) process were studied focusing on the decarburization stage. Two industrial VOD nozzles were numerically studied and compared at different temperatures and ambient pressures. Flow patterns of the oxygen jet under different ambient pressures were predicted and the flow information at different positions from the nozzle was analyzed. In addition, the effects of different ambient temperatures on the jet velocity and the dynamic pressure were compared. The predictions revealed that a little under-expansion is somewhat helpful to improve the dynamic pressure. The jet dynamic pressure and its width for the specific nozzle geometry were also studied. It was observed that a variation in the ambient pressure can influence the jet momentum and its width. In addition, a high ambient temperature was found to have a positive effect on the improvement of the jet dynamic pressure. Furthermore, it was found that a change in ambient pressure has a stronger effect on the jet force than a change in the ambient temperature. In addition, it was proved that the profiles of the dynamic pressure at a certain blowing distance fit well to Multi-Gaussian distribution. Post combustion in a BOF/LD and an AOD process during decarburization was also studied. Two mathematical models were created to show the post combustion phenomenon inside the converters, respectively. For the CFD modeling of the two processes, the realizable k-ɛ model, the species transport model and the discrete ordinate were adopted to calculate the turbulence, gas reaction and radiation present in the gas phase in the converter. For the BOF/LD modeling, a series of plant tests were conducted to collect data, which were used in the current model. These include the off-gas information, emissivity data, oxygen blowing parameters and the chemical composition of steel. After the simulation, the predicted flow pattern and detailed information of the gases taking part in the post combustion were compared to plant data. Specifically, the off-gas data from the plant was used for the model verification. The measured CO2 concentration was 15-20 wt% and the predicted value from the modeling was 16.7 wt%. For the AOD converter of interest in the current work, a fan is installed in the end of the AOD flue to help extract the off-gas from the converter. The influence of different fan gauge pressures as well as temperatures of the gas mixture, containing the generated CO and argon, on the post combustion in the whole AOD system was studied. It was indicated from the modeling results that the post combustion was only present in the flue for the present modeling conditions. Moreover, a critical fan gauge pressure (approx.. -550 Pa) was found which could yield a maximum post combustion in the flue gas. For both two models (BOF/LD and AOD), simulations indicated that a change of the converter temperature from 1500 to 1700 °C did not influence the post combustion reaction to a large degree. In addition, these two models can be regarded as the first step for a future more in-depth modeling work of the post combustion.QC 20130913
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Gray, Chase W. "Petrocapitalism in Iraqi Kurdistan: Leveraging Oil and Gas Firms in Post-War Iraq." Scholarship @ Claremont, 2012. http://scholarship.claremont.edu/cmc_theses/337.
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In the absence of a continued military presence in Iraq, the United States must use alternative means to achieve its foreign policy goals. Stated goals include maintaining influence, increasing stability in Iraq, Iran, and the Arabian Peninsula, and ensuring Iraq's territorial integrity. This paper suggests leveraging the power of American oil and gas firms operating in Iraqi Kurdistan given the relative ineffectiveness of the embassy in Baghdad and the hostility many Iraqis exhibit toward American diplomats. It first outlines American policy toward Iraqi Kurdistan from the end of the Gulf War to the present. Next it provides a brief overview of the current state of affairs in Iraqi politics and Iraq's oil and gas industry. Then the paper describes four specific ways in which supporting American oil and gas firms in Iraqi Kurdistan can help the United States achieve its foreign policy goals. First, it can check undue Shi'a centralization of power and keep Iraq from drifting too far into the Iranian sphere. Second, it can strengthen the Kurdish bargaining position with Baghdad and push Iraq toward resolving the status of Kirkuk and enacting a comprehensive hydrocarbons law. Third, oil and gas extraction through profit sharing contracts (PSCs) rather than technical services agreements (TSAs) would promote foreign direct investment and spur economic growth. Finally, private sector oil and gas companies could be a critical component in maintaining American influence with the Kurdistan Regional Government (KRG) and the Government of Iraq (GOI) through their strong local ties. The last chapter is devoted to policy prescriptions for achieving the aforementioned goals.
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CHE, MAT NORFAMILA BINTI. "Membrane Process Design for Post-Combustion Carbon Dioxide Capture." University of Toledo / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1474118357472385.
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Adeyemo, Adebola. "Post combustion capture of carbon dioxide through hydrate formation in silica gel column." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/531.
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Carbon dioxide CO₂capture through hydrate formation is a novel technology under consideration as an efficient means of separating CO₂from flue/fuel gas mixtures for sequestration and enhanced oil recovery operations. This thesis examines post-combustion capture of CO₂from fossil-fuel power plant flue-gas streams through hydrate formation in a silica gel column. Power plant flue-gas contains essentially CO₂and nitrogen (N2) after suitable pre-treatment steps, thus a model flue-gas comprising 17% co₂and 83% N2 was used in the study. Previous studies employed a stirred-tank reactor to achieve water-gas contact for formation of hydrates; recent microscopic studies involved using water dispersed in silica gel to react with gas, showing potential for improved hydrate formation rates without the need for agitation. This study focuses on macroscopic kinetics of hydrate formation in silica gel to evaluate hydrate formation rates, CO₂separation efficiency and determining optimal silica gel properties as a basis for a CO2 capture process.
Spherical silica gels with 30.0 and 100.0 nm pore sizes and 40-75 and 75-200 μm particle sizes were studied to determine pore size and particle size effects on hydrate formation. 100.0 nm pores achieved higher gas uptake and CO₂recovery over the 30.0 nm case. Improved CO₂separation was obtained when 75-200 μm particles with 100.0 nm pores were used. The two effects observed are due to improved gas diffusion occurring with larger pore and particle size, favouring increased hydrate formation. Compared to stirred-tank experiments, results in this study show a near four-fold increase in moles of gas incorporated in the hydrate per mole of water, showing that improved water-to-hydrate conversion is obtained with pore-dispersed water. At similar experimental conditions, CO₂recovery improved from 42% for stirred-tank studies to 51% for the optimum silica (100.0 nm 75-200 μm) determined in this study. Finally, effects of tetrahydrofuran (THF) - an additive that reduces operating pressure were evaluated. Experiments with 1 mol% THF, the optimum determined from previous stirred tank studies, showed improved gas consumption in silica but reduced CO₂recovery, indicating that the optimum concentration for use in silica is different from that in stirred-tank experiments.
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SOHAIL, ARFAN. "Mapping Landcover/Landuse and Coastline Change in the Eastern Mekong Delta (Viet Nam) from 1989 to 2002 using Remote Sensing." Thesis, KTH, Samhällsplanering och miljö, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-104189.
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There has been rapid change in the landcover/landuse in the Mekong delta, Viet Nam. The landcover/landuse has changed very fast due to intense population pressure, agriculture/aquaculture farming and timber collection in the coastal areas of the delta. The changing landuse pattern in the coastal areas of the delta is threatened to be flooded by sea level rise; sea level is expected to rise 33 cm until 2050; 45 cm until 2070 and 1 m until 2100. The coastline along the eastern Mekong delta has never been static, but the loss of mangrove forests along the coast has intensified coastline change. The objective of the present study is to map the changes in landcover/landuse along the eastern coast of the Mekong delta; and to detect the changes in position of the eastern coastline over the time period from 1989 to 2002.To detect changes in landuse, two satellite images of the same season, acquired by the TM sensor of Landsat 5 and the ETM+ sensor of Landsat 7 were used. The TM image was acquired on January 16, 1989 and ETM+ image was acquired on February 13, 2002. The landcover/landuse classes selected for the study are water, forest, open vegetation, soil and shrimp farms. Image differencing and post classification comparison are used to detect the changes between two time periods. Image to image correction technique is used to align satellite images. Maximum likelihood supervised classification technique is used to classify images. The result of the classification consists of five classes for 1989 and 2002, respectively. Overall accuracies of 87.5% and 86.8%, with kappa values of 0.85 and 0.84 are obtained for landuse 1989 and landuse 2002, respectively. The overall accuracy for the change map is 82% with kappa value 0.80. Post classification comparison is carried out in this study based on the supervised classification results. According to the results obtained from the post classification comparison, a significant decrease of 48% in forest and a significant increase of 74% in open vegetation and 21% in shrimp farms area observed over the entire study area. The coastline obtained by the combination of histogram thresholding and band ratio showed an overall advancement towards the South China Sea. The results showed that new land patches emerged along the eastern coast. The amount of new land patches appeared along the coast of the Mekong delta is approximately 2% of the entire study area.
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Casarin, Ariel AndreÌs. "Post-privatisation developments in network industries : the case of downstream gas markets in Argentina." Thesis, University of Warwick, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.397014.
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Van, Niekerk Susan. "The integration of GIS technology into demographic and quality of life surveying of informal settlements : Nelson Mandela Bay, South Africa." Thesis, Nelson Mandela Metropolitan University, 2009. http://hdl.handle.net/10948/881.
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A number of mostly informal areas in Nelson Mandela Bay have experienced rapid expansion over the past decade or so. Census data available for these areas is outdated and does not provide enough information for local authorities to accurately plan for tasks such as service delivery management and resource allocation. In this dissertation, a GIS based demographic and Quality of Life study of informal settlements and previously disadvantaged areas within Nelson Mandela Bay is undertaken to address this issue. The study aims to integrate GIS technology into a demographic and Quality of Life survey to significantly improve the collection, analysis, interpretation, display and management of survey data and to provide the accurate and necessary updates required between census collections. Data relating to informal settlements were captured from aerial photographs and satellite imagery and demographic and Quality of Life data were collected from field surveys. The results demonstrated that the use of GIS technology provided more accurate information for demographic variables, including the number of dwellings, dwelling type, size of the population and population dynamics. A specific demographic trend observed through spatial analysis included the identification of backyard shacks predating formal structures in settlements. The analysis and representation of the Quality of Life field survey data in GIS demonstrated how residents' perceptions of problems and issues in their neighbourhoods are better interpreted, understood and managed when analyzed within a spatial context. This research concluded that GIS based demographic and QOL studies are vital for providing accurate social and spatial information for municipalities, particularly in urban environments of developing countries, and for providing the necessary updates to censuses occurring every ten years.
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Davis, Milton W. "A stage-by-stage post-stall compression system modeling technique: methodology, validation, and application." Diss., Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/50002.
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A one-dimensional, stage-by-stage axial compression system mathematical model has been constructed which can describe system behavior during post-stall events such as surge and rotating stall. The model uses a numerical technique to solve the nonlinear conservation equations of mass, momentum, and energy. Inputs for blade forces and shaft work are provided by a set of quasi-steady stage characteristics modified by a first order lagging equation to simulate dynamic stage characteristics.
The model was validated with experimental results for a three-stage, low-speed compressor and a nine-stage, high-pressure compressor. Using these models, a parametric study was conducted to determine the effect of inlet resistance, combustor performance, heat transfer, and stage characteristic changes due to hardware modification on post—stall system behavior.Ph. D.
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Davis, Milton W. Jr. "A stage-by-stage post-stall compression system modeling technique: methodology, validation, and application." Diss., Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/50002.
Full textAbstract:
A one-dimensional, stage-by-stage axial compression system mathematical model has been constructed which can describe system behavior during post-stall events such as surge and rotating stall. The model uses a numerical technique to solve the nonlinear conservation equations of mass, momentum, and energy. Inputs for blade forces and shaft work are provided by a set of quasi-steady stage characteristics modified by a first order lagging equation to simulate dynamic stage characteristics.
The model was validated with experimental results for a three-stage, low-speed compressor and a nine-stage, high-pressure compressor. Using these models, a parametric study was conducted to determine the effect of inlet resistance, combustor performance, heat transfer, and stage characteristic changes due to hardware modification on post—stall system behavior.Ph. D.
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Higgins, Stuart James. "Design and Optimization of Post-Combustion CO2 Capture." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/80003.
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This dissertation describes the design and optimization of a CO2-capture unit using aqueous amines to remove of carbon dioxide from the flue gas of a coal-fired power plant. In particular we construct a monolithic model of a carbon capture unit and conduct a rigorous optimization to find the lowest solvent regeneration energy yet reported.
Carbon capture is primarily motivated by environmental concerns. The goal of our work is to help make carbon capture and storage (CCS) a more efficient for the sort of universal deployment called for by the Intergovernmental Panel on Climate Change (IPCC) to stabilize anthropomorphic contributions to climate change, though there are commercial applications such as enhanced oil recovery (EOR).
We employ the latest simulation tools from Aspen Tech to rigorously model, design, and optimize acid gas systems. We extend this modeling approach to leverage Aspen Plus in the .NET framework through Microsoft's Component Object Model (COM).
Our work successfully increases the efficiency of acid gas capture. We report a result optimally implementing multiple energy-saving schemes to reach a thermal regeneration energy of 1.67 GJ/tonne. By contrast, the IPCC had reported that leading technologies range from 2.7 to 3.3 GJ/tonne in 2005. Our work has received significant endorsement for industrial implementation by the senior management from the world's second largest chemical corporation, Sinopec, as being the most efficient technology known today.Ph. D.