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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
481

Sustainability of Changing Agricultural Systems in the Coastal Zone of Bangladesh

Talukder, Byomkesh 28 September 2012 (has links)
Transformations of the various agricultural systems have been taking place in the coastal zone of Bangladesh. While some farmers continue to follow traditional practices, in recent years, others have become involved in massive shrimp cultivation, shrimp-rice cultivation, a rice-based improved agricultural system or a shrimp-rice-vegetable integrated system. All these types of agriculture are being practiced under highly vulnerable environmental conditions. The long-term livelihood, food security and adaptation of the coastal people largely depend on the sustainability of these agricultural practices. In this context, assessing the level of sustainability is extremely important and will be essential for developing future policy options in Bangladesh. This study attempts to examine the sustainability of agricultural practices in the coastal region of Bangladesh. A field study was carried out in 2011 in five villages of five upazilas in the mature and active delta areas of the country. The data were collected through in-depth questionnaire surveys, focus groups discussions, field observation, key informants and secondary materials. A comprehensive suite of indicators was developed considering productivity, efficiency, stability, durability, compatibility and equity of the coastal agriculture. The categories and the indicators were weighted using Multi-Criteria Decision Analysis (MCDA) to measure the sustainability level of five study sites. The integrated agricultural system (shrimp-rice-vegetable) of Dumuria appeared to be the most sustainable system among agricultural practices, and other integrated systems (rice-based improved agricultural system) of Kalaroa were also found to show a good level of sustainability. The massive shrimp cultivation system of Shyamnagar and Kaliganj appears to be least sustainable. A traditional agriculture system with some improved methods followed in Bhola Sadar also performed in a satisfactory manner, but there were limitations in terms of its location in the active delta. The level of the sustainability measured in this study allows for a comparison among agricultural practices of the five study sites. The information generated from the study may be used in formulating policies for this part of the country. Measuring agricultural sustainability in this way produces a useful summary of sustainability issues and also provides some vital learning experiences. A holistic and interdisciplinary approach is attempted in this study for assessing and comparing the sustainability level of coastal agricultural systems. It has the potential to become useful as one of the frameworks for sustainability assessment. / Thesis (Master, Environmental Studies) -- Queen's University, 2012-09-28 15:08:18.847
482

Dynamics and prospects of non-farm employment in the coastal regions of Bangladesh

Mathbor, Golam Mohammed January 1994 (has links)
The coast of Bangladesh, comprising the complex delta of the Ganges-Brahmaputra-Meghna river system has immense resources for development. In the concept of present development efforts, this zone is among the most neglected in Bangladesh. It is very often affected by natural calamities and the situation is further aggravated by some man-made hazards, which cause heavy casualties in human lives, cattle, in reducing the size of the coastal areas and in severe damage of properties worth billions of dollars. This thesis envisages looking into the particular issue of non-farm employment. This is more important in an economy in which the land-person ratio is continuously on the decrease and dissemination of intensive crop culture has limitations. This study is exploratory in nature and uses both quantitative and qualitative methods, employing survey interviews for 80 households, 20 key informant interviews and a case study on an organization in order to assess the dynamics and prospects of non-farm employment in the coastal regions of Bangladesh. Findings of the study indicate that practically all of the non-farm field of the entire coastal belt is not yet a government priority. As such, there is need for some persuasive work in formulating some policies to develop sustainable harvests from the abundant maritime resources of the area. This will create provision for non-farm employment as well as producing a vast quantity of exportable commodities for the national well-being. It is expected that it will benefit the people of the area in particular and the entire country in general.
483

Measurement and validation of waterlines and surface currents using surf-zone video imaging.

Naicker, Jaysen. January 2001 (has links)
The continuous monitoring of beaches and structures near, or in the surf-zone, has become a vital task from an environmental and economic standpoint. Specifically, the Durban beaches are continually nourished with sand that is dredged south of the Durban Harbour mouth. Constant monitoring is essential to control the erosion and accretion of these beaches. Currently, infrequent and labour-intensive manual surveys are being used to fulfil this task. This dissertation describes the techniques used to process and validate surf-zone video images to extract information, which is equivalent but more frequent and cost effective to that obtained using manual surveying methods. The emphasis is on the extraction of accurate hourly waterlines by analysing video images obtained from Coastal Imaging stations located at Addington Beach and North Beach in Durban, South Africa and the measurement of rip currents in the surf-zone from video images together with the validation of these results. The implementation of a neural network incorporating non-local image pixel data is more reliable than previously used methods, for example, grayscale thresholding or the delta-discriminator. Grayscale thresholding relies on the difference between the water and the sand pixel intensities. The delta-discriminator incorporates hue-saturation-lightness (HSL) values to improve the discrimination between water and sand. These methods could not, however, overcome the problem of varying seasonal and diurnal light intensities and require the prior choice of threshold values. The use of non-local data, such as the average RGB-values, in addition to individual pixel values as inputs to a neural network is shown to give better results in changing ambient lighting conditions. Wavelet and Fourier analysis of the temporal nature of the breaking waves in the surf-zone is also used to calculate more accurate waterlines. These extracted waterlines are validated by data collected from manual surveys. The use of Digital Correlation Image Velocimetry (DCIV) has been proven as a successful method in tracing velocity flow fields in a fluid medium. Typically, the medium is populated with distinct seeds that are tracked through successive video frames using a cross-correlation technique. It is shown that DCIV can be used in surf-zone images to measure surface rip currents by tracking the structure of the advected foam. This technique was validated by simultaneously tracking a large number of yellow corks scattered on the water surface. / Thesis (M.Sc.)-University of Natal, Durban, 2001.
484

Geology-based site coefficients for the Upper Mississippi Embayment

Knapp, Jennifer M. 05 1900 (has links)
No description available.
485

Inverse modelling to forecast enclosure fire dynamics

Jahn, Wolfram January 2010 (has links)
Despite advances in the understanding of fire dynamics over the past decades and despite the advances in computational capacity, our ability to predict the behaviour of fires in general and building fires in particular remains very limited. This thesis proposes and studies a method to use measurements of the real event in order to steer and accelerate fire simulations. This technology aims at providing forecasts of the fire development with a positive lead time, i.e. the forecast of future events is ready before those events take place. A simplified fire spread model is implemented, and sensor data are assimilated into the model in order to estimate the parameters that characterize the spread model and thus recover information lost by approximations. The assimilation process is posed as an inverse problem, which is solved minimizing a non linear cost function that measures the distance between sensor data and the forward model. In order to accelerate the optimization procedure, the ‘tangent linear model’ is implemented, i.e. the forward model is linearized around the initial guess of the governing parameters that are to be estimated, thus approximating the cost function by a quadratic function. The methodology was tested first with a simple two-zone forward model, and then with a coarse grid Computational Fluid Dynamics (CFD) fire model as forward model. Observations for the inverse modelling were generated using a fine grid CFD simulation in order to illustrate the methodology. A test case with observations from a real scale fire test is presented at the end of this document. In the two-zone model approach the spread rate, entrainment coefficient and gas transport time are the governing invariant parameters that are estimated. The parameters could be estimated correctly and the temperature and the height of the hot layer were reproduced satisfactorily. Moreover, the heat release rate and growth rate were estimated correctly with a positive lead time of up to 30 s. The results showed that the simple mass and heat balances and plume correlation of the zone model were enough to satisfactorily forecast the main features of the fire, and that positive lead times are possible. With the CFD forward model the growth rate, fuel mass loss rate and other parameters of a fire were estimated by assimilating measurements from the fire into the model. It was shown that with a field type forward model it is possible to estimate the growth rates of several different spread rates simultaneously. A coarse grid CFD model with very short computation times was used to assimilate measurements and it was shown that spatially resolved forecasts can be obtained in reasonable time, when combined with observations from the fire. The assimilation of observations from a real scale fire test into a coarse grid CFD model showed that the estimation of a fire growth parameter is possible in complicated scenarios in reasonable time, and that the resulting forecasts at localized level present good levels of accuracy. The proposed methodology is still subject to ongoing research. The limited capability of the forward model to represent the true fire has to be addressed with more detail, and the additional information that has to be provided in order to run the simulations has to be investigated. When using a CFD type forward model, additional to the detailed geometry, it is necessary to establish the location of the fire origin and the potential fuel load before starting the assimilation cycle. While the fire origin can be located easily (as a first approximation the location of the highest temperature reading can be used), the fuel load is potentially very variable and its exact distribution might be impractical to continually keep track of. It was however shown that for relatively small compartments the exact fuel distribution is not essential in order to produce an adequate forecast, and the fuel load could for example be established based on a statistical analysis of typical compartment layouts.
486

Magmatic volatiles: A melt inclusion study of Taupo Volcanic Zone rhyolites,New Zealand

Bégué, Florence January 2014 (has links)
The central segment of the Taupo Volcanic Zone (TVZ) is one of the world’s most productive areas of silicic volcanism and geothermal activity. Rhyolites largely predominate the eruptive output in the central TVZ, with only minor basalts, andesites and dacites. The rhyolites show diversity in composition, and form a compositional continuum between two end-member types (R1 and R2), as suggested in previous studies. In this thesis I present results from a quartz- (and rare plagioclase-) hosted melt inclusions study, focussing on the volatile concentration (i.e. H2O, Cl, F, CO2) and their relative distribution between R1 and R2 rhyolites. The main objective is to add further constraints on the magmatic systems with regard to their contribution to the hydrothermal systems in the central TVZ. A comparative study between R1 and R2 melt inclusions show distinct volatile, fluid-mobile, and highly incompatible element compositions. Differences in the bulk volatile concentration of the parental magmas (i.e. basalts intruding the lower crust) are suggested to be at the origin of these volatile disparities. Further analysis on the volatile exsolution of R1 and R2 melts lead to the observation that the two rhyolite types exsolve a volatile phase at different stages in their magmatic history. From Cl and H2O concentrations, it is suggested that R1 magmas exsolve a vapour phase first, whereas R2 rhyolites more likely exsolve a hydrosaline fluid phase. These results have considerable implications for the magmatic contribution into the hydrothermal systems in the central TVZ, as differences in the composition of the resulting volatile phase may be expected. The hydrothermal systems in the central TVZ are subdivided into two groups based on their gas and fluid chemistry; and the current model suggests that there are two distinct contributions: a typical ‘arc’ system, with geochemical affinity with andesitic fluids, located along the eastern margin of the TVZ, and a typical ‘rift’ system, with geochemical affinity with rhyolitic/basaltic fluids, located along the central and/or western region of the TVZ. The addition of the new data on the rhyolitic melt inclusions, leads to a re-evaluation of the magmatic contribution into the hydrothermal systems, with a particular focus on B and Cl. The results indicate a more diverse variety of contributions to the meteoric water in the hydrothermal systems, and also show that the east-west distribution of ‘arc’ and ‘rift’ fluids is not a viable model for the central TVZ. This work emphasises that melt inclusion data and their volatile degassing history cannot be underestimated when characterising and quantifying the magmatic component in hydrothermal fluids. The melt inclusion data also provide further insight into the pre-eruptive magmatic plumbing systems and are particularly important from a hazard perspective. Included in the thesis is a detailed petrological analysis of rhyolite melt inclusions across the central TVZ and an interpretation that large silicic magma systems (in the TVZ) are typically comprised of multiple batches of magma emplaced at some of the shallowest depths on Earth. Tectonic activity is suggested to play an important role in triggering large caldera-forming eruptions as the evacuation of one magma batch could cause a regional-scale readjustment that is sufficient enough to trigger and allow simultaneous eruption of an adjacent melt batch.
487

THERMOBAROMETRY OF METAMORPHOSED PSEUDOTACHYLYTE AND DETERMINATION OF SEISMIC RUPTURE DEPTH DURING DEVONIAN CALEDONIAN EXTENSION, NORTH NORWAY

Leib, Susan E. 01 January 2013 (has links)
Crustal faulting has long been known as the source of shallow seismicity, and the seismogenic zone is the depth (3-15 km) within the crust that is capable of co-seismic slip, largely under brittle conditions. However, some continental seismicity occurs at depths >> 15 km. I performed thermobarometry of mylonitic pseudotachylyte to determine the P-T of a seismogenic extensional fault in the Caledonian Norwegian margin. Two shear zones (Eidsfjord and Fiskfjord) located in northern Norway exhibit brittle extension propagating into the ductile regime of the lower crust as evidenced by the presence of pseudotachylyte. Averages from Eidsfjord (653 ± 38°C and 570 ± 115 MPa) and Fiskfjord (680 ± 70°C and 1121 ± 219 MPa) correspond to depths of co-seismic slip of 21 ±4 km and 41 ± 9 km, respectively. These depths are 5-25 km below the depth of the standard seismogenic zone in mature fault systems, and require another mechanism (e.g. dynamic downward rupture, unusually high shear stresses) to account for seismogenic rupture at such depths. Assuming Eidsfjord and Fiskfjord were uplifted at the same time, and considering they are currently at the same crustal level, Fiskfjord was uplifted a greater amount and at a faster rate as it was initially located at a greater crustal depth.
488

How to Improve Sales Performance : Strategic Measurement in Sales, an Empirical Study at Saab.

Stephanou Hällöv, Andréa, Torehov, Jacob January 2015 (has links)
This bachelor degree study will deal with strategic measurements within sales. It undertakes an empirical evaluation of the two measurement strategy concepts “Sales Pipeline” and “Strike Zone”. Firstly, the study will explain key advantages of implementing the strategic measurements. Secondly and finally, the potential challenges as well as possible ways to overcome them will shape the structure of the study with the purpose to develop a sales process.   The foundation of the study is based on modern market trends, which is influenced on characteristics such as globalization, increased demands from customers and similarities of products and services being offered among suppliers acting on the market. These aspects among others pressures organizations to establish superior strategies in order to create a competitive advantage. The set up of successful strategies commonly entails the process of converting strategic intent into actionable activities as well as being able to measure them. Therefore the concept of measuring is an important key in developing a superior competitive advantage.   The authors worked hand in hand with the organization Saab throughout this study. Therefore, the thesis is a qualitative single case study of the organization. It will specifically investigate Saabs sales process in the market of global defense security, and evaluate key measurable strategies that can be related to their organization. According to the study findings and the analytical results, the conclusion is that both of the theories “Sales Pipeline” and “Strike Zone” will develop the sales process of Saab if the challenges of the theories can be addressed. This would be in terms of composing complements to reach a number of benefits such as an increased close rate, higher efficiency, reduced bottlenecks in the sales process, higher awareness of what types of business cases the organization should select etc.
489

The geochemical and mineralogical record of the impact of historical mining within estuarine sediments : Fal Estuary, Cornwall, UK

Hughes, Susan Helen January 2000 (has links)
No description available.
490

Paleoregolith and Unconformity-type Uranium Mineralization, Beaverlodge Lake, Great Bear Magmatic Zone, Northwest Territories

2014 March 1900 (has links)
During the Paleoproterozoic Era (ca. 2.5 Ga to 1.6 Ga), Earth underwent dramatic changes to its tectonic and atmospheric parameters. These changes included: the formation and breakup of the supercontinent Nuna (Columbia) and the gradual rise in atmospheric oxygen levels. The gradual rise in atmospheric oxygen, referred to as the Great Oxidation Event (GOE), altered the behaviour of silicate mineral weathering, and permitted the formation of new types of economic uranium deposits. Beaverlodge Lake, Northwest Territories (NT), allows for the study of a weathering profile and uranium mineralization post GOE. At Beaverlodge Lake, NT, a regolith is preserved in a rhyodacitic porphyry of the ca. 1.93 Ga Hottah plutonic complex, which is unconformably overlain by the ca. 1.9 Ga quartz arenite of the Conjuror Bay Formation. Coincident with the unconformity is a past-producing uranium deposit (called the Tatie U deposit), which was mined out in the 1930s. Other uranium showings have been discovered at Beaverlodge Lake including the Bee showing. The initial purpose of this project was to examine the regolith through field, petrography, electron microprobe analysis (EMPA), whole-rock geochemistry, and mass balance calculations. The weathering profile shows an increase in Al2O3, Fe2O3T, K2O, P2O5, Ba, and Rb, a loss in SiO2, Na2O, MgO, and Sr, and constant and low abundance of CaO. Titanium remains constant in the weathering profile. Rare earth element (REE) analysis reveals remobilization of light REE (LREE) on a micrometer scale, but no cerium anomaly is preserved in the weathering profile. The weathering profile displays characteristics similar to other post GOE paleoweathering profiles developed on felsic parental material. The timing of uranium mineralization at Tatie and Bee was constrained by in-situ U-Pb uraninite dating by Secondary Ion Mass Spectrometer (SIMS), which yielded two variably discordant ages of 1370.2 ± 7.9 Ma and 407 ± 21 Ma. In addition, REE contents of uraninite were determined by in-situ Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). Results revealed two types of uraninite mineralization are preserved at Beaverlodge Lake and they consist of synmetamorphic at Bee and basement-hosted unconformity-type at Tatie similar to those in the Athabasca Basin. The ca. 1370 Ma uraninite (Tatie) is characterized by an asymmetric bell-shaped REE pattern centered on Tb to Er where LREEs are depleted compared to heavy REEs (HREE). The ca. 407 Ma uraninite at Bee has low La concentrations and a flat to slightly negative REE pattern. The Mesoproterozoic age is similar to a Pb loss age of ca. 1400 Ma found in the Athabasca Basin. The younger Devonian age may be related to meteoric fluids cycling and uranium remobilization during the Phanerozoic.

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