• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 270
  • 165
  • 58
  • 50
  • 31
  • 15
  • 8
  • 8
  • 6
  • 6
  • 6
  • 3
  • 2
  • 2
  • 2
  • Tagged with
  • 743
  • 242
  • 112
  • 99
  • 98
  • 80
  • 69
  • 51
  • 50
  • 44
  • 43
  • 40
  • 39
  • 39
  • 38
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
161

Revitalizace vybraného úseku toku / Revitalisation of river

Kult, Jan January 2014 (has links)
The aim of my project was revitalization of the selected section of the watercourse. The subject of revitalizing modifications is the reduction slope of the bottom, supplemented by a catchment grades and a boulder slip. Other modification is reducing the tendency of banks and new draft of accompanying vegetation.
162

Slope Stability Analysis Using the Kinematic Element Method

Kader, Adnan January 2019 (has links)
Thesis regarding the application of the Kinematic Element Method to slope stability analysis in geotechnical engineering. / In this thesis, the effectiveness of the Kinematic Element Method (KEM), developed by Dr. Gussmann at the University of Stuttgart, was evaluated by comparing the solutions with the Limit Equilibrium Method (LEM), specifically the Morgenstern-Price method. The KEM was evaluated using a variety of problems, ranging from homogeneous slopes to retaining walls. The KEM was shown to predict similar potential failure mechanisms and values for the factor of safety (FS) as the Morgenstern-Price method. The FS were generally within the ±6% which is the range of variance for rigorous limit equilibrium methods. A simplified version of KEM (KEMv) was developed based on limit equilibrium formulations. In KEMv, an alternate iterative scheme to determine the FS is proposed, in which boundaries between elements are vertical. The KEMv provided similar values for the factor of safety and interelement forces as Gussmann’s KEM for vertical interelement boundaries given similar element locations. The KEM was assumed by Gussmann to be an upper bound solution. However, given the similarities in the solutions between KEM and KEMv, it may be a limit equilibrium method. The interelement forces from the KEM and KEMv were found to be sensitive to the location of the elements. Elements in the upper part of the slope often had small normal forces relative to shear forces, possibly being negative as well. Sensitivity analysis regarding the number of elements showed that a 5-element solution predicts the appropriate failure mechanism and provides a reasonably accurate FS. In a parametric study, slope geometry and soil properties were varied and comparisons were made between KEM and the Morgenstern-Price method. The KEMv displayed similar trends in factor of safety as the Morgenstern-Price method but predicted slightly larger values. The change in KEM critical slip surfaces with soil properties was consistent with trends predicted by Janbu’s dimensionless parameter. / Thesis / Master of Applied Science (MASc) / The stability of slopes is a challenging subject in geotechnical engineering. Geotechnical engineers are often interested in the factor of safety (FS), which is a quantitative measure of the stability of a slope. In this thesis, the effectiveness of the Kinematic Element Method (KEM) is evaluated by comparing its solutions to the Limit Equilibrium Method (LEM). The KEM was shown to predict similar potential failure mechanisms and values for the factor of safety. A simplified version of the KEM (KEMv) was developed based on LEM formulations. In KEMv, an alternate iterative scheme to determine the FS is proposed, in which the boundaries between elements are vertical. The KEMv provided similar values for the factor of safety and element forces as Gussmann’s KEM for vertical interelement boundaries. In a parametric study, KEM displayed similar trends in the change in FS and critical slip surface as the LEM.
163

Observância tributária: integrando paradigmas em busca de mais conformidade fiscal / Tax compliance: integrating paradigms seeking more tax compliance

Silva, Fabio Pereira da 01 July 2015 (has links)
A pesquisa sobre observância tributária floresceu no campo econômico, tendo como estudos seminais as obras de Allingham e Sandmo (1972) e Srinivasan (1973). Esses artigos basearam-se na teoria de Becker (1968) sobre crime e punição, aceitando o paradigma econômico clássico, que parte do pressuposto de que os indivíduos adotam comportamentos racionais. Nas últimas décadas, contudo, muitos pesquisadores notaram que esse paradigma, do qual derivou aquilo que veio a ser chamado pela academia de \"paradigma do crime\", explicava apenas parcialmente o comportamento do contribuinte. Surge, então, toda uma linha de pesquisa contrapondo esse paradigma racional, partindo da constatação de que o comportamento do contribuinte é muito mais complexo do que inicialmente se supunha, merecendo uma análise multidisciplinar, ou seja, que não se restrinja ao campo econômico, mas que também abarque outras disciplinas. Esse novo paradigma foi denominado pela academia de \"paradigma do serviço\" que, em linhas gerais, contempla outros fatores envolvidos no ato de pagar tributos, inclusive psicológicos, pressupondo, de tal modo, que o contribuinte não é um indivíduo racional unicamente preocupado em maximizar sua utilidade, devendo ser visto pela administração pública como uma espécie de cliente, e recebendo tratamento adequado e serviços públicos de qualidade em contrapartida ao cumprimento de suas obrigações tributárias. O presente estudo faz uma apreciação dos dois paradigmas, introduzindo nessa avaliação conceitos da ciência denominada Análise do Comportamento, cujos ensinamentos sobre a aprendizagem e o comportamento humano têm o potencial de contribuir de forma significativa para o entendimento do assunto. Testando os pressupostos teóricos apresentados no decorrer do trabalho, foram realizados dois estudos empíricos, tomando-se como base o modelo criado pelo pesquisador e psicólogo Erich Kirchler, denominado Slippery Slope Framework, que confirma estudos anteriores e demonstra que tanto punições quanto recompensas são instrumentos eficazes no combate à evasão fiscal, sugerindo que a integração dos paradigmas \"do crime\" e \"do serviço\", bem como a inserção dos princípios da Análise do Comportamento nesta análise é um caminho promissor no combate à evasão fiscal. / Research on tax compliance has arisen in the economic field with seminal studies based upon the works of Allingham and Sandmo (1972) and Srinivasan (1973). Such articles were based on Becker\'s theory (1968) on crime and punishment, accepting the classic economic paradigm, which presupposes that individuals show rational behaviors. Nevertheless, in the past decades, many researchers have noticed that such paradigm, which gave rise to what is referred to, by the academy, as \"crime paradigm\", explained the behavior of taxpayers solely in part, and an entire line of research opposing such rational paradigm arose, based upon the verification that the behavior of taxpayers is much more complex than what was originally presumed, deserving a multidisciplinary analysis, i.e., not restricted to the economic field, but that, further, encompasses other subjects. Such new paradigm was designated by the academy as \"service paradigm\" that, in general, contemplates other factors involved in the act of paying taxes, including psychological factors, thus presupposing that taxpayers are not rational individuals solely concerned about maximizing the function thereof, they should be deemed, by the public administration, to be clients, and should receive appropriate treatment and quality public services in return for complying with their tax obligations. This study analyzes two paradigms, introducing in such analysis concepts of the science called Behavior Analysis, the teachings on learning and human behavior of which have potential to significantly contribute to better understanding the subject. Testing the theoretical assumptions presented throughout the study, two empirical analyses were conducted, based upon the model created by researcher and psychologist Erich Kirchler, referred to as Slippery Slope Model, which confirms previous studies and indicates that both punishment and reward are effective tools to fight against tax evasion, suggesting that integrating \"crime\" and \"service\" paradigms and inserting concepts of the Behavior Analysis Science in this analysis is highly promising to fight against tax evasion.
164

Jämförelse av beräkningsprogrammen Novapoint Geosuite Stability och Geoslope SLOPE/W med avseende på släntstabilitet / Comparison of the Calculation Programs Novapoint Geosuite Stability and Geoslope SLOPE/W with Regards to Slope Stability

Hagerfors, Jonas January 2019 (has links)
This thesis deals with the difference between two calculation programs for slope stability, namely Geoslope SLOPE/W and Novapoint GeoSuite Stability. The purpose of the thesis is to compare the two calculation programs with regard to the analysis of slope stability, as well as the two programs' handling of data. The two calculation programs use different Limit equilibrium methods to calculate safety factor and sliding surfaces for slopes. It can be expected that the result should be similar to one another, as well as the fact that both the calculation programs use different Limit equilibrium methods, but also when large differences in both safety factor and critical sliding surface give unreliable results. The thesis will also address the factors that may lie behind the fact that a possible stability failure should take place in a slope, as it gives an increased understanding of the analyzes that have been done. The work was carried out by modeling slopes with identical geometric relationships and identical material properties in the two calculation programs, a safety factor and a critical sliding surface for the slopes were developed for both programs and then compared with each other. / Föreliggande examensarbete behandlar skillnaden mellan två beräkningsprogram när det kommer till släntstabilitet, nämligen Geoslope SLOPE/W och Novapoint GeoSuite Stability. Syftet med examensarbetet är att jämföra de båda beräkningsprogrammen avseende vid undersökning av släntstabilitet, samt de två programmens hantering av data. De två beräkningsprogrammen använder sig av liknande Limit equilibrium-metoder för att beräkna säkerhetsfaktor samt glidytor för slänter. Man kan förvänta sig att resultatet bör vara varandra likt då dels att de både beräkningsprogrammen använder sig av liknande Limit equilibrium-metoder, men också då stora skillnader i både säkerhetsfaktor och kritisk glidyta ger opålitligt resultat. Examensarbetet kommer även ta upp de faktorer som kan ligga bakom att ett eventuellt brott ska ske i en slänt, då det ger ökad förståelse för de analyser som gjorts. Arbetet utfördes genom att slänter med identiska geometriska relationer samt identiska materialegenskaper modellerades i de båda beräkningsprogrammen, en säkerhetsfaktor samt kritisk glidyta för slänterna togs fram för båda programmen och jämfördes sedan med varandra.
165

Quasi-Continuous GPS Steep Slope Monitoring: A Multi-Antenna Array Approach

Forward, Troy Andrew January 2002 (has links)
This thesis investigates the design, implementation and validation of a multi-antenna GPS system to monitor the displacement of deforming slopes. The system utilises a switched antenna array design allowing data from multiple antennas to be sampled sequentially by one GPS receiver. The system provides quasi-continuous GPS observations that can produce a precise and reliable coordinate time-series of the movement of the slope under consideration. GPS observations and particularly those concerned with the monitoring of steep slopes, are subject to systematic errors that can significantly degrade the quality of the processed position solutions. As such, this research characterises the data in terms of multipath effects, the spectrum of the coordinate time-series, and the carrier to noise power density ratio of the raw GPS observations. Various GPS processing parameters are then investigated to determine optimal processing parameters to improve the precision of the resulting coordinate time-series. Results from data stacking techniques that rely on the daily correlation of the repeating multipath signature find that the GPS data actually decorrelates somewhat from day to day. This can reduce the effectiveness of stacking techniques for the high precision monitoring of steep slopes. Finally, advanced stochastic models such as elevation angle and carrier-to-noise weighting are investigated to optimise the precision of the coordinate time-series data. A new in-line stochastic model is developed based on weighting GPS observations with respect to the level of systematic error present within the data. By using these advanced types of stochastic models, reductions to the noise level of the coordinate time-series of approximately 20 and 25 percent are possible in the horizontal and height components respectively. / Results from an extensive field trial of this system on a deforming high-wall of an open-pit mine indicate that approximately 135mm of displacement occurred over the 16-week field trial. The precision of the coordinate time-series for surface stations approaches ±4.Omm and ±5.4mm in the horizontal and height components respectively. For sub-surface stations next to the mine wall, coordinate precision has been determined as ±4.9mm.component and ±7.6mm in the height component respectively.
166

Management of Geohazards at Lihir Gold Mine-Papua New Guinea

Singh, Mohan 11 1900 (has links)
Lihir Gold Mine in Papua New Guinea is one of the largest gold mines in the world situated in a seismically sensitive zone. The gold deposit is located in an extinct volcano in close proximity to the sea shore and presents a series of geohazards. Some geohazards are uncommon and include: geothermal outbursts, cavities, water inrush and earthquake/ tsunami. After a major multi-batter (5 benches high) slope failure that occurred on the 1st of October 2009, a team of engineers, lead by the author investigated the incident and made series of recommendations. Arising out of these recommendations, a comprehensive Geohazard Management Plan was formulated by revisiting, revising and putting together all the individual geohazard management plans as a single document. This thesis describes the outcomes of the investigation and presents an overview and systematic approach in formulation of the Geohazard Management Plan, apart from a summary of the gaps that were identified in the existing system, major contributions that were made as well as the expected improvements and constraints in managing these geohazards. / Mining Engineering
167

Eigenvalue Problem for the 1-Laplace Operator / Das Eigenwertproblem für den 1-Laplace-Operator

Milbers, Zoja 27 March 2009 (has links) (PDF)
We consider the eigenvalue problem associated to the 1-Laplace operator. We define higher eigensolutions by means of weak slope and establish existence of a sequence of eigensolutions by using nonsmooth critical point theory. In addition, we deduce a new necessary condition for the first eigenvalue of the 1-Laplace operator by means of inner variations. / Wir betrachten das zum 1-Laplace-Operator gehörige Eigenwertproblem. Wir definieren höhere Eigenlösungen mittels weak slope und weisen die Existenz einer Folge von Eigenlösungen nach, indem wir die nichtglatte Theorie kritischer Punkte anwenden. Zusätzlich leiten wir eine neue notwendige Bedingung für den ersten Eigenwert des 1-Laplace-Operators mittels innerer Variationen her.
168

Management of Geohazards at Lihir Gold Mine-Papua New Guinea

Singh, Mohan Unknown Date
No description available.
169

Investigation of the California Undercurrent off the west coast of Vancouver Island

Krassovski, Maxim 14 August 2008 (has links)
Current meter records from a long term mooring site on the continental slope off the west coast of Vancouver Island, British Columbia, Canada are used to investigate the scales of variability of the subsurface California Undercurrent and its relation to possible driving mechanisms. Observed along the west coast of North America from Baja California to Vancouver Island, the California Undercurrent is part of the California Current System, a typical basin-scale eastern boundary circulation system. Of the four instruments at nominal depths of 35, 100, 175, and 400 m, the upper two show seasonally reversing flow, while the 175 m instrument registers a year-round poleward flow. The deepest current meter, located approximately 100 m above the bottom, reflects the influence of a nearby submarine canyon. The flow at 100 and 175 m depths, as well as the water properties sampled in the region with CTD casts, are characteristic of the temporal and spatial variability of the California Undercurrent over the continental slope off central and southern Vancouver Island. The correlation of the 175 m flow with local atmospheric forcing (wind stress) in the low-frequency band (periods of months) is higher than with ocean-wide climatic indices, suggesting that regional processes play a key role in the forcing of the subsurface flow.
170

The biogeochemical source and role of soluble organic-Fe(III) complexes in continental margin sediments

Beckler, Jordon Scott 12 January 2015 (has links)
In the past couple of decades, the discovery that iron is a limiting nutrient in large regions of the ocean has spurred much research into characterizing the biogeochemical controls on iron cycling. While Fe(II) is soluble at circumneutral pH, it readily oxidizes to Fe(III) in the presence of oxygen. Fe(III) is highly insoluble at circumneutral pH, presenting organisms with a bioavailability paradox stemming from the physiological challenge of using a solid phase mineral for assimilatory or dissimilatory purposes. Interestingly, dissolved organic-Fe(III) complexes can be stable in seawater in the presence of oxygen, and an active flux of these complexes has recently been measured in estuarine sediments. Their sources and biogeochemical role, however, remain poorly understood. In this work, a suite of field and laboratory techniques were developed to quantify diagenetic processes involved in the remineralization of carbon in marine sediments in situ, investigate the role of these organic-Fe(III) complexes in sediment biogeochemistry, and characterize the composition of the ligands possibly involved in the solubilization of Fe(III) in marine sediments. The first-of-its-kind in situ electrochemical analyzer and HPLC was used to better constrain diagenetic processes that may lead to the formation of dissolved organic-Fe(III) complexes in the Altamaha estuary and Carolina slope. An intensive study of the Satilla River estuary reveals that dissimilatory iron-reduction contributes to the formation of sedimentary organic-Fe(III) complexes, which are demonstrated to serve as an electron acceptor in subsequent incubations with a model iron-reducing microorganism. Similar observations in deep-sea slope and abyssal plain sediments fed by the Mississippi and Congo Rivers suggest that dissimilatory iron reduction may represent an important component of carbon remineralization in river-dominated ocean margin sediments that may be currently underestimated globally. To confirm that these organic-Fe(III) complexes are produced during microbial iron reduction, novel separation schemes were developed to extract and identify Fe(III)-binding ligands from sediment pore waters. Preliminary results reveal the presence of a few select low-molecular weight compounds in all pore waters extracted, suggesting they might be endogenous ligands secreted by iron-reducing bacteria to non-reductively dissolve Fe(III) minerals prior to reduction.

Page generated in 0.024 seconds