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Auswahl der wissenschaftlichen Literatur zum Thema „Globally expensive land“
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Zeitschriftenartikel zum Thema "Globally expensive land"
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Müller, Alexander, Josef Schmidhuber, Jippe Hoogeveen und Pasquale Steduto. „Some insights in the effect of growing bio-energy demand on global food security and natural resources“. Water Policy 10, S1 (01.03.2008): 83–94. http://dx.doi.org/10.2166/wp.2008.053.
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Growing crops for biofuels is often criticized because of its direct competition for land for food production. The recent price increases on world food markets are partly a result of this competition. For instance, cereals prices have increased by more than 60% since 2005 and in 2006 sugar prices peaked at a level twice as high as the level of previous years. There are concerns whether these increases will continue and if the world will run out of resources for food production. According to the authors, these concerns are largely unwarranted. For one, higher prices for food also mean that feedstocks are becoming increasingly expensive for bio-energy production and this endogenously limits the amount of feedstocks that will be used in the energy market. In addition, there is no imminent global resource shortage, neither for land nor for water that would support these concerns. Even with an expanding world population there is globally still enough land and water to grow a substantial amount of biomass for both food and bio-energy production. However, there is an uneven distribution of natural resources, resulting in huge regional differences with important areas experiencing major land and water shortages. China and India, for example, account together for more than 35% of the total global population and both have exploited most of the land and water resources available for agriculture. On the other hand, sub-Saharan Africa and South America still have the potential, in terms of suitable land and exploitable water, to expand areas for agricultural production. The growing demand for bio-energy will have a negative and positive effect on food. Higher food prices can increase food insecurity among the urban poor and the rural landless population. On the other hand higher prices and more marketable production can stimulate the agricultural sector and create new opportunities for rural communities. At the national level it can offer development opportunities for countries with significant resources.
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Holloway, Jacinta, Kate J. Helmstedt, Kerrie Mengersen und Michael Schmidt. „A Decision Tree Approach for Spatially Interpolating Missing Land Cover Data and Classifying Satellite Images“. Remote Sensing 11, Nr. 15 (31.07.2019): 1796. http://dx.doi.org/10.3390/rs11151796.
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Sustainable Development Goals (SDGs) are a set of priorities the United Nations and World Bank have set for countries to reach in order to improve quality of life and environment globally by 2030. Free satellite images have been identified as a key resource that can be used to produce official statistics and analysis to measure progress towards SDGs, especially those that are concerned with the physical environment, such as forest, water, and crops. Satellite images can often be unusable due to missing data from cloud cover, particularly in tropical areas where the deforestation rates are high. There are existing methods for filling in image gaps; however, these are often computationally expensive in image classification or not effective at pixel scale. To address this, we use two machine learning methods—gradient boosted machine and random forest algorithms—to classify the observed and simulated ‘missing’ pixels in satellite images as either grassland or woodland. We also predict a continuous biophysical variable, Foliage Projective Cover (FPC), which was derived from satellite images, and perform accurate binary classification and prediction using only the latitude and longitude of the pixels. We compare the performance of these methods against each other and inverse distance weighted interpolation, which is a well-established spatial interpolation method. We find both of the machine learning methods, particularly random forest, perform fast and accurate classifications of both observed and missing pixels, with up to 0.90 accuracy for the binary classification of pixels as grassland or woodland. The results show that the random forest method is more accurate than inverse distance weighted interpolation and gradient boosted machine for prediction of FPC for observed and missing data. Based on the case study results from a sub-tropical site in Australia, we show that our approach provides an efficient alternative for interpolating images and performing land cover classifications.
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Evans, Steven, Gustavious P. Williams, Norman L. Jones, Daniel P. Ames und E. James Nelson. „Exploiting Earth Observation Data to Impute Groundwater Level Measurements with an Extreme Learning Machine“. Remote Sensing 12, Nr. 12 (25.06.2020): 2044. http://dx.doi.org/10.3390/rs12122044.
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Groundwater resources are expensive to develop and use; they are difficult to monitor and data collected from monitoring wells are often sporadic, often only available at irregular, infrequent, or brief intervals. Groundwater managers require an accurate understanding of historic groundwater storage trends to effectively manage groundwater resources, however, most if not all well records contain periods of missing data. To understand long-term trends, these missing data need to be imputed before trend analysis. We present a method to impute missing data at single wells, by exploiting data generated from Earth observations that are available globally. We use two soil moisture models, the Global Land Data Assimilation System (GLDAS) model and National Oceanic and Atmospheric Administration (NOAA) Climate Prediction Center (CPC) soil moisture model to impute the missing data. Our imputation method uses a machine learning technique called Extreme Learning Machine (ELM). Our implementation uses 11 input data-streams, all based on Earth observation data. We train and apply the model one well at a time. We selected ELM because it is a single hidden layer feedforward model that can be trained quickly on minimal data. We tested the ELM method using data from monitoring wells in the Cedar Valley and Beryl-Enterprise areas in southwest Utah, USA. We compute error estimates for the imputed data and show that ELM-computed estimates were more accurate than Kriging estimates. This ELM-based data imputation method can be used to impute missing data at wells. These complete time series can be used improve the accuracy of aquifer groundwater elevation maps in areas where in-situ well measurements are sparse, resulting in more accurate spatial estimates of the groundwater surface. The data we use are available globally from 1950 to the present, so this method can be used anywhere in the world.
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Rimal, Bhagawat, Sean Sloan, Hamidreza Keshtkar, Roshan Sharma, Sushila Rijal und Uttam Babu Shrestha. „Patterns of Historical and Future Urban Expansion in Nepal“. Remote Sensing 12, Nr. 4 (13.02.2020): 628. http://dx.doi.org/10.3390/rs12040628.
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Globally, urbanization is increasing at an unprecedented rate at the cost of agricultural and forested lands in peri-urban areas fringing larger cities. Such land-cover change generally entails negative implications for societal and environmental sustainability, particularly in South Asia, where high demographic growth and poor land-use planning combine. Analyzing historical land-use change and predicting the future trends concerning urban expansion may support more effective land-use planning and sustainable outcomes. For Nepal’s Tarai region—a populous area experiencing land-use change due to urbanization and other factors—we draw on Landsat satellite imagery to analyze historical land-use change focusing on urban expansion during 1989–2016 and predict urban expansion by 2026 and 2036 using artificial neural network (ANN) and Markov chain (MC) spatial models based on historical trends. Urban cover quadrupled since 1989, expanding by 256 km2 (460%), largely as small scattered settlements. This expansion was almost entirely at the expense of agricultural conversion (249 km2). After 2016, urban expansion is predicted to increase linearly by a further 199 km2 by 2026 and by another 165 km2 by 2036, almost all at the expense of agricultural cover. Such unplanned loss of prime agricultural lands in Nepal’s fertile Tarai region is of serious concern for food-insecure countries like Nepal.
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Li, Wenbo, Dongyan Wang, Shuhan Liu, Yuanli Zhu und Zhuoran Yan. „Reclamation of Cultivated Land Reserves in Northeast China: Indigenous Ecological Insecurity Underlying National Food Security“. International Journal of Environmental Research and Public Health 17, Nr. 4 (13.02.2020): 1211. http://dx.doi.org/10.3390/ijerph17041211.
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The competition for land resources created by the need for food security and ecological security is intensifying globally. To resolve the issue of land scarcity in agriculture following rapid urbanization, China implemented its requisition–compensation balance policy of cultivated lands in 1997, the introduction of which consumed numerous areas of land, such as river shoal and bare land, through reclamation. Moreover, these reclaimed and newly cultivated lands were mainly distributed in the northern part of China. Most previous studies of this subject have only examined the overall balance of cultivated lands in well-developed regions, and there is a lack of knowledge about the indigenous gains and losses before and after reclamation in important areas such as northeast China. Therefore, this study selected two representative county-level units in northeast China as the study area to analyze the conversion of cultivated land reserves during 1996–2015, evaluate the performance of reclaimed cultivated lands in terms of quality and productivity and calculate reclamation-induced changes in ecosystem service value. The results indicated that by 2015 only 16.02% of the original cultivated land reserves remained unconverted; nearly 60% were reclaimed as cultivated lands and over 20% were converted to other land resources. River shoal and ruderal land were the primary resources for cultivated lands compensation, and marsh, bare land and saline-alkaline land were found to be converted the most thoroughly. The gain of 23018.55 ha reclaimed cultivated lands were of relatively inferior quality and lower productivity, contributing approximately 4.32% of total grain output. However, this modest gain was at the expense of a 768.03 million yuan ecosystem services loss, with regulating services and supporting services being undermined the most. We argue that even if northeast China continues to shoulder the responsibility of compensating for a majority of cultivated land losses, it still needs to carefully process reclamation and introduce practical measures to protect indigenous ecosystems, in order to better serve the local residents and ensure prolonged food security with sustainability.
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Sárvári, Balázs, und Anna Szeidovitz. „The Political Economics of the New Silk Road“. Baltic Journal of European Studies 6, Nr. 1 (01.02.2016): 3–27. http://dx.doi.org/10.1515/bjes-2016-0001.
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AbstractWhat has now been coined the term XXI Century Silk Road had evolved from a speech given by Chinese premier Xi Jinping in Kazakhstan in 2013. It was initially a plan aimed at promoting the bilateral relations of China and its neighbors; however, the initiative had since then traversed the region’s borders and become a global project. This paper examines the Silk Road Economic Belt initiative in light of Chinese-EU relations. It reviews the initiation of the Silk Road Project and focuses on its political economic analysis through investigating the potential routes the Belt can take, the EU-Chinese trade and investment standings as well as the global political context that the increased cooperation and connection is likely to influence. The paper uses the Modern Silk Road concept as an example of China’s foreign policy in the wake of globalization and the emergence of a new multipolar world order. To set the stage we will begin with a political-economic approach of the New Silk Road. Highlighting the possibilities of Chinese high culture, which accommodate global governance, we state that the Modern Silk Road project is one of its materialized forms. The concept of the New Silk Road (together with the Eurasian Union) denies the previous era of corruption and personality cult and indicates a milestone in the development of China, proving that it is already a globally responsible power (Värk, 2015). Even if transport by land is significantly more expensive than transportation by sea, the New Silk Road may have significant advantages: It may take only two weeks, saving potentially a week in shipping time, and diversify China’s dependence on sea transport that could reduce the importance of its regional diplomatic conflicts. Already these aspects show that the purpose of the Modern Silk Road is basically not to explore cost-efficiency but to contribute to the establishment of a new, multipolar world order. The fact that the Modern Silk Road is a supply-driven concept in spite of the historical one underlines this argument. Even if politics dominate, henceforward directing the economic activities, we will nonetheless examine the China-Eastern European relations through the lenses of trade and investment as well. After the initial analysis and description of the Silk Road Economic Belt as a tool of Chinese foreign policy, the paper goes on to examine the potential routes the railway takes from China to Europe. It reviews the trade and investment ties that the two entities share and assesses how this initiative contributes to the rise of Europe and China beside the USA. Lastly, it outlines how various regional and global powers are affected by the renewal of the Silk Road.
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Blair, Dale, Charlie Shackleton und Penelope Mograbi. „Cropland Abandonment in South African Smallholder Communal Lands: Land Cover Change (1950–2010) and Farmer Perceptions of Contributing Factors“. Land 7, Nr. 4 (16.10.2018): 121. http://dx.doi.org/10.3390/land7040121.
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Despite agricultural land abandonment threatening the food security and the livelihoods of smallholder farmers, it is pervasive globally and in developing countries. Yet land abandonment is an understudied aspect of land use change in social–ecological systems. Here we provide more information on this phenomenon by exploring cropland abandonment during 1950–2010 in four former South African ‘homelands’—part of the ‘Apartheid’ era racially-based land allocation programs—characterized by rural, smallholder farmers. Cropland abandonment 1950–2010 was widespread in all surveyed sites (KwaZulu: 0.08% year−1, Transkei: 0.13% year−1, Lebowa: 0.23% year−1, Venda: 0.28% year−1), with rates peaking between 1970 and 1990, with concomitant increases (up to 0.16% year−1) of woody vegetation cover at the expense of grassland cover. Active and past farmers attributed cropland abandonment to a lack of draught power, rainfall variability and droughts, and a more modernized youth disinclined to living a marginal agrarian lifestyle. We discuss the potential social and ecological implications of abandoned croplands at the local and regional scales, as the deagrarianization trend is unlikely to abate considering the failure of current South African national agricultural incentives.
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Kocur-Bera, Katarzyna, und Hubert Frąszczak. „Coherence of Cadastral Data in Land Management—A Case Study of Rural Areas in Poland“. Land 10, Nr. 4 (10.04.2021): 399. http://dx.doi.org/10.3390/land10040399.
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The cadaster functions laid down in the law should guarantee the safety of one’s rights. The reliability of the data gathered in the cadaster affects decisions concerning specific real estate or taken within the sphere of economic management. The legislation often requires the use of cadastral data, which makes it necessary to keep it up-to-date and coherent with the situation in the field. The effects of a lack of coherence may impact public finances and land management. Maintaining high-quality cadastral data is time-consuming and expensive. This study analysed the data coherence between the state in the field and cadastral documents. The analysis was based mainly on the information about the area of a plot and land use. The coherence index showed that the differences between registers and the state in the field range from 30% to 80%. This can be changed by comprehensive data modernisation, which can be facilitated using modern technology. Given the diverse use of cadastral data and the global trends in cadaster development and implementation of the third dimension, the currency and reliability of cadastral data become particularly important.
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Füss, Roland, Jan A. Koller und Alois Weigand. „Determining Land Values from Residential Rents“. Land 10, Nr. 4 (25.03.2021): 336. http://dx.doi.org/10.3390/land10040336.
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The value of land is determined by the locations’ attractiveness and the degree of direct land use regulation. When regulations are binding, e.g., when a restriction on the maximum floor area ratio exists, the land price can be directly expressed as a function of the maximum floor area ratio and local amenities. We show theoretically and empirically how this approach can be used to determine land values from rental prices of residential structures built upon that land. From our empirical results, we derive two main sources for a monocentric structure of land prices. First, the location attractiveness of centrally located dwellings makes land prices more expensive. Second, as the maximum floor area ratio is high in central areas, the regulation works as a multiplier for land prices and inflates prices accordingly. Our model gives insights into the determinants of urban land prices and provides a useful approach for land appraisal in regions where land transactions are scarce.
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Martínez-Valderrama, Jaime, María E. Sanjuán, Gabriel del Barrio, Emilio Guirado, Alberto Ruiz und Fernando T. Maestre. „Mediterranean Landscape Re-Greening at the Expense of South American Agricultural Expansion“. Land 10, Nr. 2 (17.02.2021): 204. http://dx.doi.org/10.3390/land10020204.
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The stabling of livestock farming implies changes in both local ecosystems (regeneration of forest stands via reduced grazing) and those located thousands of kilometers away (deforestation to produce grain for feeding livestock). Despite their importance, these externalities are poorly known. Here we evaluated how the intensification and confinement of livestock in Spain has affected forest surface changes there and in South America, the largest provider of soybeans for animal feed to the European Union. For this purpose, we have used Spanish soybean import data from Brazil, Paraguay and Argentina and a land condition map of Spain. The area of secondary forest in Spain that has regenerated as a result of livestock stabling has been ~7000 kha for the decade 2000–2010. In the same period, 1220 kha of high value South American ecosystems (e.g., Chaco dry Forest, Amazonian rainforest or Cerrado) have been deforested. While these figures may offer a favorable interpretation of the current industrial livestock production, it is not possible to speak of compensation when comparing the destruction of well-structured ecosystems, such as primary South American forests, with the creation of secondary forest landscapes in Spain, which are also prone to wildfires. Our results highlight how evaluating land use change policies at a national or regional level is an incomplete exercise in our highly telecoupled and globalized world.
Buchteile zum Thema "Globally expensive land"
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Ewert, Alan W., Denise S. Mitten und Jillisa R. Overholt. „Outcomes, benefits, and opportunities: western research trends.“ In Health and natural landscapes: concepts and applications, 52–66. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789245400.0005.
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Abstract This book chapter discusses and presents some of the research outcomes connecting human well-being and landscapes and explores the complexities inherent in the development of a field of study. In learning more about the research, it encourages readers to keep in mind: (1) a primary goal of researching landscapes and human interactions is to help us discover more about creating or maintaining mutually beneficial relationships between humans and natural landscapes based on an understanding that the two are entwined (2) it is less expensive (financially, psychologically, and socially) to keep people healthy than to have people regain their health. If nature is accessible and helps people stay healthy, there are positive financial implications for healthcare (3) studying human interactions with landscapes through a systems approach is required to successfully operationalise and apply research to address well-being concerns equitably and globally. Socioecological research-based solutions consider a system of wellbeing incorporating both human health and environmental health (4) the positive health benefits of exposure to land and seascapes on human systems are not accessible to all populations because of economic disparities, location, and health conditions, and (5) globally, nature and human well-being relationship findings have useful implications for individual well-being, public health, and landscape design.
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Kroeze, Ronald, Pol Dalmau und Frédéric Monier. „Introduction: Corruption, Empire and Colonialism in the Modern Era: Towards a Global Perspective“. In Palgrave Studies in Comparative Global History, 1–19. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-0255-9_1.
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AbstractScandal, corruption, exploitation and abuse of power have been linked to the history of modern empire-building. Colonial territories often became promised lands where individuals sought to make quick fortunes, sometimes in collaboration with the local population but more often at the expense of them. On some occasions, these shady dealings resulted in scandals that reached back to the metropolis, questioning civilising discourses in parliaments and the press, and leading to reforms in colonial administrations. This book is a first attempt to discuss the topic of corruption, empire and colonialism in a systematic manner and from a global comparative perspective. It does so through a set of original studies that examines the multi-layered nature of corruption in four different empires (Great Britain, Spain, the Netherlands and France) and their possessions in Asia, the Caribbean, Latin America and Africa.
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Fitzhugh, H. A. „Competition between Livestock and Mankind for Nutrients: Let Ruminants Eat Grass“. In Feeding a World Population of More Than Eight Billion People. Oxford University Press, 1998. http://dx.doi.org/10.1093/oso/9780195113129.003.0024.
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As we contemplate the challenge of feeding more than 8 billion people —more than three quarters living in developing countries —the even greater challenge will be feeding their grandchildren. Consideration of competition between livestock and mankind for nutrients must include both near-term food needs and long-term sustainability of agricultural production systems. Producing more livestock products at the expense of eroding the natural resource base is not an acceptable solution. Livestock have been denigrated as both competitors for food and degraders of the natural resource base for food production. These often emotionally argued allegations against livestock generally do not stand up to objective analysis. Livestock arc most often complementary elements of food production systems, converting otherwise unused feed sources to highly desired food and livestock products such as leather and wool. Moreover, well-managed livestock are positive contributors to the natural resources base supporting balanced agricultural systems. In this chapter, the following points are addressed from the perspective of current and future role for livestock in feeding 8 billion people: . . . • Growing demands for human food and livestock feed • Domesticated food-producing animals • World livestock production systems • Human food preferences and requirements • Dietary requirements and conversion efficiencies • Contributions of science to livestock improvement . . . The overarching issue is the difference in the current and future role for livestock in developed and in developing regions. Less than 11 percent of the global land mass of 13.3 billion hectares is cultivated; the remainder supports permanent pasture, 26%; forest, 31%; and other nonagricultural uses, 32% (U.N. data as cited by Waggoner, 1994). The concerns about competition between livestock and mankind for nutrients center primarily on grains and legumes grown on arable land. Even the most avid vegetarians have little taste for the forages and other herbaceous materials from pasturelands, forests, roadsides, and fence rows that arc consumed by livestock. Since the 18th century, the amount of land cultivated has increased from approximately 0.3 to 1.5 billion ha (Richards, 1990, as cited by Waggoner, 1994). This increase in cultivated land has primarily come at the expense of forest and grasslands.
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Kugara, Stewart Lee, Thizwilondi Joanbeth Madima und Ndidzulafhi Esther Ramavhunga. „The Fight Against Climate Change From an Indigenous System Perspective“. In Handbook of Research on Protecting and Managing Global Indigenous Knowledge Systems, 45–59. IGI Global, 2022. http://dx.doi.org/10.4018/978-1-7998-7492-8.ch003.
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The 21st century has witnessed that climate change has become an acute daily agony. In Africa, to be specific, it has made the attainment of the Millennium Development Goals (MDGs) and Sustainable Development Goals a myth. It is argued that the implications of climate change are evident in numerous ways on the African continent: incessant floods, cyclones, droughts, and heat waves. These have introduced disastrous outcomes: a heightened threat of food security, inadequate water resource availability, diminished biodiversity, decline in human health viability, and increasing land degradation. At the centre of all this, a more robust understanding of climate change and appropriate palliatives is called for. In South Africa, conservation by the state and numerous stakeholders on the thorny issue of climate change has tended to favour and privilege Western scientific interpretations at the expense of the “indigenous” interpretations as informed by their indigenous epistemologies.
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Rahman, Hakikur. „Interactive Multimedia Technologies for Distance Education in Developing Countries“. In Encyclopedia of Multimedia Technology and Networking, Second Edition, 735–41. IGI Global, 2009. http://dx.doi.org/10.4018/978-1-60566-014-1.ch099.
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With the extended application of information technologies, the conventional education system has crossed the physical boundaries to reach the unreached through virtual education system. In distant mode of education, students get opportunity to education through self-learning methods with the use of technology-mediated techniques. Accumulating a few other available technologies, efforts are being made to promote distance education in remotest regions of the developing countries through institutional collaborations and adaptive use of collaborative learning systems (Rahman, 2000a). Distance education in a networked environment demands extensive use of computerized LAN/WAN, excessive use of bandwidth, expensive use of sophisticated networking equipment, and in a sense, this is becoming a hard-to-achieve target in developing countries. High initial investment cost always demarcates thorough usage of networked hierarchies where the basic backbone infrastructure of IT is in a rudimentary stage. Furthermore, multimedia puts additional pressure on communications systems with types of information flow, bandwidth requirements, development of local and wide area networks with a likely impact on narrowband and broadband ISDN. Developed countries are taking a leading role in spearheading distance education through flexible learning methods, and many renowned universities of the western world are offering highly specialized and demanding distance education courses by using their dedicated high bandwidth computer networks. Many others have accepted a dual mode of education, rather than sticking to the conventional education system. Research indicates that teaching and studying at a distance can be as effective as traditional instruction when the method and technologies used are appropriate to the instructional tasks with intensive learner-to-learner interactions, and instructor-to-learner interactions. Radio, television, and computer technologies, including the Internet and interactive multimedia methods, are major components of the virtual learning methodologies. The goals of distance education, as an alternative to traditional education, have been to offer accredited education programs, to eradicate illiteracy in developing countries, to provide capacity development programs for better economic growth, and to offer curriculum enrichment in the nonformal educational arena. Distance education has experienced dramatic global growth since the early 1980s. It has evolved from early correspondence learning using primarily print-based materials into a global movement using various technologies.
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Orr, David W. „2020: A Proposal“. In The Nature of Design. Oxford University Press, 2002. http://dx.doi.org/10.1093/oso/9780195148558.003.0023.
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By a large margin 1998 was the warmest year ever recorded. The previous year was the second warmest (IPCC 2001). A growing volume of scientific evidence indicates that, given present trends, the combustion of fossil fuels, deforestation, and poor land-use practices will cause a major, and perhaps self-reinforcing, shift in global climate (Houghton 1997). With climatic change will come severe weather extremes, superstorms, droughts, killer heat waves, rising sea levels, spreading disease, accelerating rates of species loss, and collateral political, economic, and social effects that we cannot imagine. We are conducting, as Roger Revelle (quoted in Somerville 1996, 35) once noted, a one-time experiment on the earth that cannot be reversed and should not be run. The debate about climatic change has, to date, been mostly about scientific facts and economics, which is to say a quarrel about unknowns and numbers. On one side are those, greatly appreciated by some in the fossil fuel industry, who argue that we do not yet know enough to act and that acting prematurely would be prohibitively expensive (Gelbspan 1998). On the other side are those who argue that we do know enough to act and that further procrastination will make subsequent action both more difficult and less efficacious. In the United States, which happens to be the largest emitter of greenhouse gases, the issue is not likely to be discussed in any constructive manner. And the U.S. Congress, caught in a miasma of ideology and partisanship, is in deep denial, unable to act on the Kyoto agreement that called for a 7 percent reduction of 1990 carbon dioxide levels by 2012. Even that level of reduction, however, would not be enough to stabilize climate. To see our situation more clearly we need a perspective that transcends the minutiae of science, economics, and current politics. Because the effects, whatever they may be, will fall most heavily on future generations, understanding their likely perspective on our present decisions would be useful to us now. How are future generations likely to regard various positions in the debate about climatic change? Will they applaud the precision of our economic calculations that discounted their prospects to the vanishing point? Will they think us prudent for delaying action until the last-minute scientific doubts were quenched?
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„(b) Effective destruction of a hotel in the centre of Mexico City 70 following the earthquake in September 1985 3.3 The environment at risk (a) Branches of cactus plants are stacked for collection at the 71 roadside, Haiti (b) Two Ethiopian women carry fuel wood to a nearby town 71 4.1 (a) and (b) A message from a Gambian school, West Africa 81 (c) Children in Senegal, West Africa, take a break from 81 working on the land 4.2 The development gap (a) Expensive addition to the natural beauty of Sydney harbour 86 (b) Calcutta, India, temporary drain-dwellers 86 4.3 Moneyspider 92 4.4 ‘Monopoly’ 92 4.5 Global contrasts, transactions and conflicts (a) Non-ferrous metal ores are smelted at La Oroya, in the 96 central Andes of Peru (b) Smoke from a copper smelter in central Chile, near 97 Valparaiso 5.1 Signs of the times in the European Union (a) Belgium’s French-speaking region of Wallonia is announced 107 by the twelve stars of the EU (b) In Catalonia, Spain, speakers of both Spanish and Catalan 107 are warned of the danger of entering a river bed“. In Geography of the World's Major Regions, 648. Routledge, 2003. http://dx.doi.org/10.4324/9780203429815-158.
Der volle Inhalt der QuelleKonferenzberichte zum Thema "Globally expensive land"
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Zuo, Baifang, David L. Black und Clifford E. Smith. „A New Assumed PDF Turbulent Combustion Model for Multi-Step Chemistry“. In ASME Turbo Expo 2005: Power for Land, Sea, and Air. ASMEDC, 2005. http://dx.doi.org/10.1115/gt2005-68133.
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The effect of turbulence on chemical reactions is known to be important in many gas turbine combustor applications. There are only a few established models that can capture turbulence-combustion interaction in CFD codes, and all of these models are either very expensive (e.g. Monte Carlo PDF model) or limited in what types of flames can be analyzed (e.g. laminar flamelet). Assumed PDF models have been a popular choice because they are inexpensive and can handle all flame types (e.g. diffusion, premixed and partially premixed). However, assumed PDF models are typically restricted to single, one-step global mechanisms; or are a function of species and quickly become computationally expensive. CFD Research Corporation has recently developed and validated a new assumed PDF turbulence chemistry interaction model for multi-step chemistry. The model adopts an assumed, two-variable joint-PDF to model a wide-range of turbulent reacting flows. The two variables defining the PDF are the mixture fraction and reaction progress, representing species diffusion and flame propagation. A significant advantage of this new approach is its wide range of applicability for premixed, diffusion, and partially premixed flames. Allowing more detailed chemistry for species and combustion predictions enables complex chemical reaction processes including pollutant formation, flame ignition, and flame quenching to be studied. The model is also computationally efficient, with only a minor increase in computational expense with either species or number of global reaction steps. The newly developed model was first validated using a diffusion flame from a piloted burner developed at the University of Sydney. Three different methane bulk jet velocities were used to investigate the model’s behavior on turbulent diffusion flames. Simulation data were compared with the experimental measurements and the simulation results performed by Pope (Masri and Pope, 1990) using a velocity-composition joint PDF transport equation solved by the Monte Carlo method. To validate the model on premixed flames, the data of Moreau et al. (Moreau et al., 1974, 1976, 1977) were used. Data were collected on a mixing layer stabilized burner, where the main flow into the combustor was a premixed mixture of methane and air. Parallel to the main stream, a pilot stream of hot combustion products at 2000 K was injected for flame stabilization. The results demonstrate the wide applicability of the new model for practical, turbulent combustion applications.
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Papadopoulos, J. M., C. Qiao und A. T. Myers. „Concept for a Wind-Yawing Shallow-Draft Floating Turbine“. In ASME 2021 3rd International Offshore Wind Technical Conference. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/iowtc2021-3561.
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Abstract Offshore wind turbines are poised to become a vital part of the global energy landscape — particularly the floating types which give access to a much greater wind power resource. The design possibilities for floating turbines are so different from onshore and offshore fixed-bottom turbines, that a cost-reducing re-imagining may be justified. Apart from the expense of an offshore transmission cable and substation, the costs of hardware for offshore bottom-fixed wind turbines (CAPEX) are roughly twice as much as for onshore. Much of the extra cost can be attributed to the mass of the above- and underwater support and expensive installation. In this paper, we reconsider two aspects of present-day offshore turbines: (a) maintaining a land-turbine architecture (a slender tower with the rotor cantilevered from a yawing, equipment-filled nacelle); (b) seeking to minimize wave-induced motion and loads of the above-water plant. Our aim is an offshore floating design that is potentially less expensive than offshore fixed-bottom units. We outline the preliminary structural analyses that underlie a design focused on weight, cost reduction, and ease of manufacturing. This includes lattice towers, tubular hub and axle, and needle-roller bearings. The biggest concerns about the proposed lightweight system involve motions and forces induced by waves. Shallow-draft floats will follow the waves, leading to greater rotor translation and precession; and lattice towers may be subject to impact loads, ice buildup, and fouling. We present analysis of some of these motions and forces, along with resulting estimates for required structural weight as a preliminary investigation into the feasibility of this lightweight concept.
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Yi, Weilin, Hongyan Huang und Wanjin Han. „Design Optimization of Transonic Compressor Rotor Using CFD and Genetic Algorithm“. In ASME Turbo Expo 2006: Power for Land, Sea, and Air. ASMEDC, 2006. http://dx.doi.org/10.1115/gt2006-90155.
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The paper describes a new optimization strategy for computationally expensive design optimization problems of turbomachinery, combined with design of experiment (DOE), response surface models (RSM), genetic algorithm (GA) and a 3-D Navier-Stokes solver. Data points for response evaluations were selected by Latin hypercube design (LHD) and 3-dimensional Navier-Stokes analysis was carried out at these sample points. The quadratic response surface model was used to approximate the relationships between the design variables and flow parameters. The genetic algorithm was applied to the response surface model to perform global optimization to obtain the optimum design. The above method was applied to the optimization design of NASA rotor37. The object was to maximize the adiabatic efficiency. An optimum leading edge line was found which produced a new 3-dimensional blade combined with sweep and composite bowing. As a result of this optimization, the adiabatic efficiency was successfully increased by 1.58%. It was found that the strategy of this paper provides a reliable design optimization method for turbomachinery blades at reasonable computing cost.
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Kyprianidis, Konstantinos G., Ramon F. Colmenares Quintero, Daniele S. Pascovici, Stephen O. T. Ogaji, Pericles Pilidis und Anestis I. Kalfas. „EVA: A Tool for EnVironmental Assessment of Novel Propulsion Cycles“. In ASME Turbo Expo 2008: Power for Land, Sea, and Air. ASMEDC, 2008. http://dx.doi.org/10.1115/gt2008-50602.
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This paper presents the development of a tool for EnVironmental Assessment (EVA) of novel propulsion cycles implementing the Technoeconomical Environmental and Risk Analysis (TERA) approach. For nearly 3 decades emissions certification and legislation has been mainly focused on the landing and take-off cycle. Exhaust emissions measurements of NOx, CO and unburned hydrocarbons are taken at Sea Level Static (SLS) conditions for 4 different power settings (idle, descent, approach and take-off) and are consecutively used for calculating the total emissions during the ICAO landing and take-off cycle. With the global warming issue becoming ever more important, stringent emissions legislation is soon to follow, focusing on all flight phases of an aircraft. Unfortunately, emissions measurements at altitude are either extremely expensive, as in the case of altitude test facility measurements, or unrealistic, as in the case of direct in flight measurements. Compensating for these difficulties, various existing methods can be used to estimate emissions at altitude from ground measurements. Such methods, however, are of limited help when it comes to assessing novel propulsion cycles or existing engine configurations with no SLS measurements available. The authors are proposing a simple and fast method for the calculation of SLS emissions, mainly implementing ICAO exhaust emissions data, corrections for combustor inlet conditions and technology factors. With the SLS emissions estimated, existing methods may be implemented to calculate emissions at altitude. The tool developed couples emissions predictions and environmental models together with engine and aircraft performance models in order to estimate the total emissions and Global Warming Potential of novel engine designs during all flight phases (i.e. the whole flight cycle). The engine performance module stands in the center of all information exchange. In this study, EVA and the described emissions prediction methodology have been used for the preliminary design analysis of three spool high bypass ratio turbofan engines. The capability of EVA to radically explore the design space available in novel engine configurations, while accounting for fuel burn and global warming potential during the whole flight cycle of an aircraft, is illustrated.
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Sanz, W., M. Mayr und H. Jericha. „Thermodynamic and Economic Evaluation of an IGCC Plant Based on the Graz Cycle for CO2 Capture“. In ASME Turbo Expo 2010: Power for Land, Sea, and Air. ASMEDC, 2010. http://dx.doi.org/10.1115/gt2010-22189.
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The IEA World Energy Outlook 2009 predicts a considerable growth of the world’s primary energy demand and states that fossil fuels will remain the dominant source of primary energy. Among them coal will increase its share because of its vast reserves, its relatively even global distribution and its low prices compared to oil and gas. On the other hand the burning of coal emits larger quantities of CO2 than oil and gas. As CO2 is the leading cause for global warming, the use of coal for power generation demands a clean coal technology with carbon capture and storage (CCS). Therefore in this work it is suggested to combine a coal gasification unit with a Graz Cycle power plant, an oxy-fuel technology of highest efficiency. The firing of the syngas from coal gasification with pure oxygen avoids the expensive pre-combustion CO2 sequestration and leads to a working fluid of CO2 and steam, where CO2 is captured by simple steam condensation. In contrast to this, the more conventional technology is to send the syngas to a water-shift reactor and a CO2 scrubber so that a fuel containing mainly hydrogen is obtained which can be fired in a conventional combined cycle plant. In order to evaluate these two competing technologies a thermodynamic simulation as well as an economic cost analysis of both power cycles is performed. It turns out that the achievable efficiency of the Graz Cycle plant is — despite of the increased oxygen demand — far higher than that of a plant of conventional capture technology due to the avoidance of shift reaction and scrubbing. The following economic analysis shows mitigation costs of 22.5 €/ton CO2 avoided for the Graz Cycle plant compared to 33 €/ton for an IGCC plant with CO2 capture.
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Wade, A. S., D. B. Ingham, A. G. Kyne, N. S. Mera, M. Pourkashanian und C. W. Wilson. „Optimisation of the Arrhenius Parameters in a Semi-Detailed Mechanism for Jet Fuel Thermal Degradation Using a Genetic Algorithm“. In ASME Turbo Expo 2004: Power for Land, Sea, and Air. ASMEDC, 2004. http://dx.doi.org/10.1115/gt2004-53367.
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This paper presents a novel way to determine new reaction rate parameters (A’s and Ea’s in the Arrhenius expression) in a semi-detailed reaction mechanism for the thermal degradation of aviation fuel and surface fouling. The technique employed is a specialised optimisation procedure, namely a genetic algorithm (GA), which utilises an abstraction of the Darwinian principle of survival of the fittest in order to “breed” good solutions over a predefined number of “generations”. Deposition rates for a given fuel which have been measured experimentally over a range of conditions are reproduced by solving the conservation equations of mass, momentum, energy and species using a CFD code and the optimised set of rate constants obtained using a genetic algorithm inversion process. The new set of rate constants lie within predefined boundaries based upon previous values found in the literature for the mechanism being used. In addition, this powerful technique promises the ability to develop reaction mechanisms whose newly optimised rate constants reproduce closely all the experimental data available, enabling a greater confidence in their predictive capabilities. The process is also shown to be an effective tool to facilitate the elucidation of shortcomings in current global chemistry models of fuel degradation. Therefore, the results of this study demonstrate that the genetic algorithm inversion process may be used to develop and calibrate more detailed models for the thermal stability behaviour of aviation fuels than have been seen previously and, subsequently, accurately predict the locations and rates of deposit build-up in fuel handling systems. Furthermore, it has been demonstrated that, modern high speed computers allow for evaluation of increasingly complex and expensive GA objective functions.
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Sahoo, Shubhashisa, Shankar C. Subramanian und Suresh Srivastava. „Sensitivity Analysis of Vehicle Parameters for Heading Angle Control of an Unmanned Ground Vehicle“. In ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-39685.
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Even if there are many software and mathematical models available in the literature to analyze the dynamic performance of Unmanned Ground Vehicles (UGVs), it is always difficult to identify or collect the required vehicle parameters from the vehicle manufacturer for simulation. In analyzing the vehicle handling performance, a difficult and complex task is to use an appropriate tire model that can accurately characterize the ground-wheel interaction. Though, the well-known ‘Magic Formula’ is widely used for this purpose, it requires expensive test equipment to estimate the Magic Formula coefficients. The design of longitudinal and lateral controllers plays a significant role in path tracking of an UGV. Though the speed of the vehicle may remain almost constant in most of the maneuvers such as lane change, Double Lane Change (DLC), step steer, cornering, etc., design of the lateral controller is always a challenging task as it depends on the vehicle parameters, road information and also on the steering actuator dynamics. Although a mathematical model is an abstraction of the actual system, the controller is designed based on this model and then deployed on the real system. In this paper, a realistic mathematical model of the vehicle considering the steering actuator dynamics has been developed by calculating the cornering stiffnesses from the basic tire information and the vertical load on each tire. A heading angle controller of the UGV has been considered using the Point-to-Point navigation algorithm. Then, these controllers have been implemented on a test platform equipped with an Inertial Measurement Unit (IMU) and a Global Positioning System (GPS). A wide range of experiments such as J-Turn, lane change and DLC have also been conducted for comparison with the simulation results. Sensitivity analysis has been carried out to check the robustness and stability of the controller by varying the cornering stiffness of tires, the most uncertain parameter. The longitudinal speed of the vehicle is assumed to vary between a minimum value of 1.4 m/s and a maximum value of 20 m/s. It has been found that when the vehicle is moving at a constant velocity of 3.2 m/s, a heading angle change of 20 degrees can be achieved within 3 seconds with 2% steady state error using a proportional controller. It was observed that at lower speeds, the controller is more sensitive to the steering actuator dynamics and at higher speeds, the controller is more sensitive to the cornering stiffness of tires.
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Mazumder, Malay, Mark Horenstein, Jeremy Stark, Daniel Erickson, Arash Sayyah, Steven Jung und Fang Hao. „Development of Self-Cleaning Solar Collectors for Minimizing Energy Yield Loss Caused by Dust Deposition“. In ASME 2013 7th International Conference on Energy Sustainability collocated with the ASME 2013 Heat Transfer Summer Conference and the ASME 2013 11th International Conference on Fuel Cell Science, Engineering and Technology. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/es2013-18365.
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Concentrated Solar Power (CSP) systems used for photothermal conversion of solar energy to electricity are capable of meeting a large fraction of the global energy requirements. CSP plants are inherently robust with respect to the availability of materials, technology, and energy storage. However, dust depositions on solar collectors cause energy yield loss annually, ranging from 10 to 50% depending upon their location in the semi-arid and desert lands. Mitigation of energy loss requires manual cleaning of solar mirrors with water. A brief review of the soiling related losses in energy yield of the CSP plants is presented, which shows that cleaning of the CSP mirrors and receivers using water and detergent is an expensive and time-consuming process at best and is often impractical for large-scale installations where water is scarce. We report here our research effort in developing an electrodynamic dust removal technology that can be used for keeping the solar collectors clean continuously without requiring water and manual labor. Transparent electrodynamic screens (EDS), consisting of rows of transparent parallel electrodes embedded within a transparent dielectric film can be integrated on the front surface of the mirrors and on the receivers for dust removal for their application as self-cleaning solar collectors. When the electrodes are activated, over 90% of the deposited dust is removed. A summary of the current state of prototype development and evaluation of EDS integrated solar mirrors and experimental data on the removal of desert dust samples are presented. A brief analysis of cost-to-benefit ratio of EDS implementation for automated dust removal from large-scale solar collectors is included.