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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.
1

Comparing Methods for Measuring the Volume of Sand Excaveted by a Laboratory Cutter Suction Dredge Using an Instrumented Hopper Barge and a Laser Profiler

Manikantan, Arun 2009 December 1900 (has links)
The research focuses on the various methods that could be used in the laboratory to determine the values of production from a model cutter suction dredge. The values of production obtained from different methods are compared to estimate the best value. The tests were conducted in an attempt to pave the way to find spillage from the cutter suction dredge. The development of these methods is useful for evaluating the sediment spillage and residuals during dredging. The more accurate the values of production the more accurate would be the values of spillage. For this purpose, the laboratory dredge carriage and dredge/tow tank located at the Haynes Coastal Engineering Laboratory at Texas A&M University is used. During the summer of 2007 and 2008, the laboratory dredge carriage was used to dredge sand (d50 = 0.27 mm) in the sediment pit that is 7.6 m (25 feet) long, 3.7 m (12 feet) wide and 1.5 m (5 feet) deep. A laser profiler, a model hopper barge attached with pressure gauges, a flowmeter and density gauge aid in determining the production from the laboratory model of the cutter suction dredge were used. The before and after bathymetry measurements using a laser profiling system are used to determine the amount of sediment remaining after dredging. The hopper is instrumented with pressure gauges to measure the amount of sediment contained in the hopper. The laboratory dredge system has a magnetic flowmeter and nuclear density gauge that provide data to calculate the amount of sand delivered to the hopper. The difference between the sand volume from the before and after bathymetry is the amount of sand that is resuspended and subsequently resettles in the dredging area (residual) and the sand that is not picked up by the dredge (spillage). Many issues in laboratory testing were found during the course of testing and solutions were found. The production values are compared with reasoning as to why the differences occur. The results demonstrate the ability and difficulty of measuring the amount of material that is dredged and the amount of spillage and residuals that occurs during dredging.
2

The Impact of Mindfulness on Non-Malicious Spillage within Images on Social Networking Sites

Landress, Angela D. 01 January 2018 (has links)
Insider threat by employees in organizations is a problematic issue in today’s fast-paced, internet-driven society. Gone are the days when securing the perimeter of one’s network protected their business. Security threats are now mobile, and employees have the ability to share sensitive business data with hundreds of people instantaneously from mobile devices. While prior research has addressed social networking topics such as trust in relation to information systems, the use of social networking sites, social networking security, and social networking sharing, there is a lack of research in the mindfulness of users who spill sensitive data contained within images posted on social networking sites (SNS). The author seeks to provide an understanding of how non-malicious spillage through images relates to the mindfulness of employees, who are also deemed insiders. Specifically, it explores the relationships between the following variables: mindfulness, proprietary information spillage, and spillage of personally identifiable information (PII). A quasi-experimental study was designed, which was correlational in nature. Individuals were the unit of analysis. A sample population of business managers with SNS accounts were studied. A series of video vignettes were used to measure mindfulness. Surveys were used as a tool to collect and analyze data. There was a positive correlation between non-malicious spillage of sensitive business, both personally identifiable information and proprietary data, and a lack of mindfulness.
3

Optimal use of rainwater tanks to minimize residential water consumption

Khastagir, Anirban, anirban.khastagir@rmit.edu.au January 2008 (has links)
Melbourne, the capital of Victoria Australia leads the world in having the highest quality drinking water. The Victorian State Government has set targets for reducing per capita water consumption by 15%, 25% and 30% by 2010, 2015 and 2020 respectively and has announced stringent water restrictions to curtail water demand. In this resource constraint environment it is opportune to look for alternative sources of water to supplement Melbourne's traditional water supply. In Melbourne, legislation has been changed to make it possible to use rainwater harvested from domestic tanks for non potable purposes. The annual rainfall in Melbourne's metropolitan area varies from 450mm in the West to 850mm in the East to over 1000mm in the North East mountain ranges. The objectives of the current study are to develop a methodology to estimate the optimal size of the rainwater tank at a particular location considering the local rainfall, roof area, demand for water and the reliability of supply (supply security) required; to quantify the rainwater volume that could be harvested at site using domestic rainwater tanks to minimise pressure on the potable water supply secured from traditional catchment sources until the desalination plant is commissioned in 2013; to analyse the efficacy of rainwater tanks to reduce the stormwater runoff and improve the quality of the stormwater that will otherwise flow into urban drains and to estimate the cost effectiveness ratio and payback period of inst alling rainwater tanks. A simple water balance model was developed to calculate the tank size based on daily rainfall, roof area and the expected demand. The concept of 'reliability' was introduced to measure supply security. Rainfall data from 20 rainfall stations scattered around Melbourne were used to determine the variation in the rainwater tank size dependent on the above stated parameters. It was observed that to achieve the same supply reliability (90%) and to meet a specific demand (toilet and garden use), the tank size required in the western side of Melbourne is as high as 7 times as that required in the north-east side. As a result, the
4

Public Health Implications of Oil Pollution in Koluama: Nigeria

Sako, Esther Bridget 01 January 2017 (has links)
As the global demand for oil increases, human health implications related to its discovery and transport remain a serious concern. The Niger Delta has been the site of severe environmental degradation since the oil boom of the 1970s. While some researchers have examined the environmental effects of oil procurement, few have explored human health implications in this region. This phenomenological study investigated the human physical and mental health consequences of oil-related environmental degradation through the perceptions and lived experiences of villagers in Koluama, Nigeria. The conceptual framework for the study was based on research conducted by Morello-Frosch, Zuk, Jerrett, Shamasunder and Kyle (2011) on the public health consequences of environmental pollution to which marginalized populations are vulnerable. Participants included a random sample of 33 residents of Koluama. Data were collected via individual semistructured interviews and 3 focus groups and analyzed using: interpretative phenomenological analysis. Themes that emerged from analysis included children's health issues, including asthma and other breathing problems; and death rates among the elderly in the area. The villagers, aware of the increase in mortality and illness in the area, also suffered from anxiety and depression. The research findings demonstrated the perception of the participants that the oil companies appeared not to be concerned about the lack of health care in the area; although illness increased in the area of the oil fields. This study might be beneficial in eliciting positive social change at the individual and organizational levels by illuminating oil-related health problems and may lead to better health care access for the population.
5

Modellering av vattenkraft i Spine - En studie om gränserna för vattenkraften som reglerande energikälla i framtidens elsystem

Lien-Oscarsson, Fredrik, Sibo, Tony January 2021 (has links)
In this paper a system of hydropower plants isanalyzed with the aim of finding a breaking point at which thesystem can no longer handle an alternating electric load whilekeeping the water spillage at a minimum. A model of a partof A° ngermana¨lven with ten power plants were implemented inthe optimization software Spine in order to achieve this. Themodel was then supplied with data of two very challenging casescenarios during a year of operation. The result shows that thesystem, when met with a frequently changing load during theperiod of high local inflow, is able to sustain a high load whilemaintaining stability. On the other hand the case of having thelowest local inflow combined with the highest reservoir levels isalso stable but only with a lower electric load. In conclusion;hydropower systems appear to play a key role in controllingpotential variations in the power system due to its flexibility andstoring capacity. A broader look at large hydropower systemsin Sweden would, however, give us a clearer picture of how wellthese systems can serve as a compensatory energy source in futureCO2-free power systems. / I den här rapporten analyseras ett system avvattenkraftverk med målet att hitta brytpunkten för när systemetinte längre kan tillgodose en skiftande last samtidigt som spill avvatten hålls minimalt. En modell av en del av ångermannälvenimplementerades med tio kraftverk i optimeringsprogrammetSpine för att uppnå detta. Modellen kompletterades sedan meddata från de två veckor då förhållandena för drift var somvärst. Resultatet visar att systemet är stabilt när det belastasmed en snabbt skiftande last och ger då högst elproduktionnär tillrinningen är maximal. Veckan med lägst tillrinning samthögst vattennivå i reservoarerna modellerades också, dock medlägre elproduktion. Slutsatserna som kan dras är att system avvattenkraft verkar vara en viktig del i elproduktionen för attkunna kompensera potentiella variationer i framtida el-system.En mer omfattande studie och modell av vattenkraftverk skulledock ge en bättre bild av hur väl dessa system kan agera som denkompensatoriska faktorn i framtidens koldioxidfria el-system. / Kandidatexjobb i elektroteknik 2021, KTH, Stockholm
6

Environmental Control in Oil & Gas Exploration & Production : A Case Study of the Niger Delta Region of Nigeria, West Africa

Ibem-Ezera, Victor January 2010 (has links)
<p>The goal of this study is to examine the environmental impacts of oil and gas exploration and production (E&P), the roles of legislation, and the environmental management strategies in the petroleum industry with respect to the Niger Delta region of Nigeria. The study seeks to suggest sustainable solutions to the endemic economic, social, and environmental problems associated with oil and gas E&P in the region. The focus is on the environmental control in the upstream (E&P) operations of the oil and gas industry as it affects the Niger Delta region of Nigeria with a view to proffering sustainable solutions.</p><p>The heavily polluting activities and environmental impacts of the upstream oil and gas operations in the Niger Delta have over the years taken a routine dimension and are endemic as a result of inadequate environmental legislations and ineffective enforcements. Sequel to these environmental impacts is militancy, adoption of expatriates, communal conflicts, inter-ethnic conflicts, human right abuses, restiveness and other social vices as the study reveals. These social and environmental impacts of oil and gas activities in this region bring impoverishment, abject poverty, hunger, squalor, birth disease, gene mutation, and death while exposing inhabitants of the region to afflictions and diseases as the study explicitly documents.</p><p>The study also reveals that the persistence rate of unrest, restiveness, militancy and other social vices is as a result of non-dialogue status between the different stakeholders, lack of infrastructural development, lack of basic amenities, high rate of unemployment, poor policy construct, federalized mineral right / resource ownership structure, and the monopolistic nature of Nigeria’s foreign exchange earning in petroleum resources.</p><p>In this dissertation, both proactive and corrective measures to curb the menace of the social, economic and environmental impacts of oil and gas exploration & production operations in Nigeria are presented and discussed with suggestions to sustainable solution and development, better environmental legislation, and better resource policy construct while advocating for good industrial practices in the petroleum industry with emphasis on the Niger Delta region of Nigeria.</p>
7

Environmental Control in Oil &amp; Gas Exploration &amp; Production : A Case Study of the Niger Delta Region of Nigeria, West Africa

Ibem-Ezera, Victor January 2010 (has links)
The goal of this study is to examine the environmental impacts of oil and gas exploration and production (E&amp;P), the roles of legislation, and the environmental management strategies in the petroleum industry with respect to the Niger Delta region of Nigeria. The study seeks to suggest sustainable solutions to the endemic economic, social, and environmental problems associated with oil and gas E&amp;P in the region. The focus is on the environmental control in the upstream (E&amp;P) operations of the oil and gas industry as it affects the Niger Delta region of Nigeria with a view to proffering sustainable solutions. The heavily polluting activities and environmental impacts of the upstream oil and gas operations in the Niger Delta have over the years taken a routine dimension and are endemic as a result of inadequate environmental legislations and ineffective enforcements. Sequel to these environmental impacts is militancy, adoption of expatriates, communal conflicts, inter-ethnic conflicts, human right abuses, restiveness and other social vices as the study reveals. These social and environmental impacts of oil and gas activities in this region bring impoverishment, abject poverty, hunger, squalor, birth disease, gene mutation, and death while exposing inhabitants of the region to afflictions and diseases as the study explicitly documents. The study also reveals that the persistence rate of unrest, restiveness, militancy and other social vices is as a result of non-dialogue status between the different stakeholders, lack of infrastructural development, lack of basic amenities, high rate of unemployment, poor policy construct, federalized mineral right / resource ownership structure, and the monopolistic nature of Nigeria’s foreign exchange earning in petroleum resources. In this dissertation, both proactive and corrective measures to curb the menace of the social, economic and environmental impacts of oil and gas exploration &amp; production operations in Nigeria are presented and discussed with suggestions to sustainable solution and development, better environmental legislation, and better resource policy construct while advocating for good industrial practices in the petroleum industry with emphasis on the Niger Delta region of Nigeria.
8

On the Dynamics and Statics of Power System Operation : Optimal Utilization of FACTS Devicesand Management of Wind Power Uncertainty

Nasri, Amin January 2014 (has links)
Nowadays, power systems are dealing with some new challenges raisedby the major changes that have been taken place since 80’s, e.g., deregu-lation in electricity markets, significant increase of electricity demands andmore recently large-scale integration of renewable energy resources such aswind power. Therefore, system operators must make some adjustments toaccommodate these changes into the future of power systems.One of the main challenges is maintaining the system stability since theextra stress caused by the above changes reduces the stability margin, andmay lead to rise of many undesirable phenomena. The other important chal-lenge is to cope with uncertainty and variability of renewable energy sourceswhich make power systems to become more stochastic in nature, and lesscontrollable.Flexible AC Transmission Systems (FACTS) have emerged as a solutionto help power systems with these new challenges. This thesis aims to ap-propriately utilize such devices in order to increase the transmission capacityand flexibility, improve the dynamic behavior of power systems and integratemore renewable energy into the system. To this end, the most appropriatelocations and settings of these controllable devices need to be determined.This thesis mainly looks at (i) rotor angle stability, i.e., small signal andtransient stability (ii) system operation under wind uncertainty. In the firstpart of this thesis, trajectory sensitivity analysis is used to determine themost suitable placement of FACTS devices for improving rotor angle sta-bility, while in the second part, optimal settings of such devices are foundto maximize the level of wind power integration. As a general conclusion,it was demonstrated that FACTS devices, installed in proper locations andtuned appropriately, are effective means to enhance the system stability andto handle wind uncertainty.The last objective of this thesis work is to propose an efficient solutionapproach based on Benders’ decomposition to solve a network-constrained acunit commitment problem in a wind-integrated power system. The numericalresults show validity, accuracy and efficiency of the proposed approach. / <p>The Doctoral Degrees issued upon completion of the programme are issued by Comillas Pontifical University, Delft University of Technology and KTH Royal Institute of Technology. The invested degrees are official in Spain, the Netherlands and Sweden, respectively.QC 20141028</p>

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