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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.
141

Optimisation of the bottom stirring praxis in a LD-LBE converter : Investigations and tests on phosphorous removal, nitrogen as stirring gas, and slopping

Aguirre Castillo, José January 2015 (has links)
The LD-process, called after the cities Linz and Donawitz, is used to convert pig iron into crude steel by blowing oxygen on top of the pig iron. A LD-LBE converter, Lance Bubbling Equilibrium, also stirs the melt trough a bottom stirring system. The bottom stirring in a LD-LBE converter is believed to have a positive effect alone on the phosphorous removal. Previous studies have shown that the temperature and slag composition are the main factors affecting phosphorus removal. Phosphorus binds to the slag easier at low temperature and to slag with certain levels of dissolved calcium (a process additive). Different praxes were tested and a better dephosphorisation was reached. The bottom stirrings effect on the dissolution of calcium additives is a possible explanation to the results and mechanisms presented in this study. The study also aimed to investigate the use of nitrogen as stirring gas instead of argon. Nitrogen is removed from the steel during the formation of carbon oxide gases. Nitrogen was used in varying amounts as stirring gas during the first half of the oxygen blow. It proved to be safe to use as long as there was a high content of carbon in the melt. However using nitrogen beyond half of the blow showed to be risky for nitrogen sensible steels; even in small amounts since there is not enough carbon left to degas the steel from nitrogen. Slopping happens when formed gas from the LD-process is trapped in the slag. The slag level rises and sometimes it floods the converter resulting in yield losses. The influence of the bottom stirring on slopping was studied, which resulted in the conclusion that slopping cannot be avoided by simply improving the bottom stirring. Although some verification studies remains to be done, if the suggestions based on the results of this thesis were employed, savings in the oxygen and stirring gas economies could be made. Not least improvements on the iron yield. / En järnmalmsbaserad stålproduktion börjar med att järnmalm matas i en masugn tillsammans med koks, kalk och tillsatsämnen. Ut kommer råjärn med höga kol och svavelhalter. Råjärnet transporteras till stålverket i så kallade torpedvagnar. I vissa stålverk, t.ex. SSAB Special Steels i Oxelösund, renas råjärnet från svavel i torpedvagnen. I andra stålverk svavelrenar man i separata skänkar. Svavelreningen sker med bland annat kalciumkarbid som binder till svavlet. Det svavelfattiga råjärnet måste sedan renas från kol för att bli stål. Det görs i en LD-konvertern (Linz Donawitz). LD-konvertern laddas med flytande råjärn som har en kolhalt på 4,5 procent och som är runt 1350 grader varmt. Råjärnet kyls genom att cirka 20 procent skrot tillsätts. En syrgaslans sänks sedan in i konvertern ovanför smältan och reningen startar.  Syrgaslansen blåser syrgas i ultraljudsfart vilket oxiderar en del av järnet, så väl som kol, kisel, mangan, fosfor and andra föroreningsämnen i råjärnet. Kol försvinner ur konvertern i form av kolmonoxidgas. Andra oxiderade föroreningar och järnoxid bildar tillsammans en så kallad slagg som flyter ovanpå smältan. Det tillsätts även så kallade slaggbildare som förbättrar upptaget av föroreningar i slaggen. Processen varar i cirka 17 minuter och är mycket beroende av slaggen som bildas. Kol försvinner ur konvertern i form av kolmonoxidgas. Under processens gång rör man om smältan med hjälp av gaser som spolas genom botten av konvertern. Omröringen jämnar ut smältans sammansättning och temperatur. När man inte länge behöver avlägsna kol stoppas processen. Stålets temperatur är då cirka 1700 grader och kolhalten ligger nära 0,05 procent. Stålet överförs sedan till en skänk för att skilja det ur slaggen. Stålet förädlas vidare i olika processer där sammansättningen justeras så att det möter kundens krav. Sedan gjuts stålet i strängar för transport till valsverk eller kunder. Denna studie behandlar bottenomrörningen under LD-processen i SSAB Special Steels's stålverk i Oxelösund. Omrörningen sker genom åtta porösa stenar i botten av konvertern som blåser med argon eller kväve. Gasflödet genom stenarna justeras genom ett ventilsystem. Under blåsningen rör man om med hjälp av förinställda program. Omrörningens primära funktion är att avlasta syrgaslansen. I fallen där ingen bottenomrörning finns måste syrgaslansen blåsa ”hårdare” på stålet för att avlägsna kol. Avlastningen som bottenomrörningen bidrar med gör att processen även kallas för LD-LBE, där LBE står för Lans Bubbling Equilibrium. Bottenomrörningen tros ha en positiv effekt på stålets rening från fosfor. Sedan tidigare vet man att temperatur och slaggsammansättning är de största faktorerna som påverkar fosforreningen. Fosfor tas lättare upp i slaggen vid låga temperaturen samt i slagg med högre kalkhalter. Olika omrörningsprogram testades och en bättre fosforrening nåddes. Bottenomrörningen visade sig ha positiva effekter som är teoretisk kopplade till kalksmältning. Två möjliga förklaringsmekanismer hittades. Studien undersökte även användningen av kväve som omrörningsgas istället för argon, då kväve är ekonomisk fördelaktig gentemot argon. Kväve finns inlöst i råjärnet som sätts in i konvertern. Kvävgasen försvinner ur stålet under och med hjälp av kolreningen. Det visade sig vara säkert att använda kväve från start fram till halva syrgasblåset på kvävekänsliga stålsorter, var efter man sedan byte till argon. Kväve som används sent under blåset visade ge högre kvävehalter. Urkok är en kraftig volymökning av slaggen som sker när bildad gas från reningen av smältan fångas i slaggen och får slaggen att ”koka över”. Urkok resulterar i ekonomiska förluster då slaggen som lämnar konvertern vid urkok är rik på järn. Bottenomrörningens eventuella påverkan på urkok studerades. Det visade sig att urkok inte kan undvikas genom att enbart optimera bottenomrörningen.
142

Salt Tectonics and Its Effect on Sediment Structure and Gas Hydrate Occurrence in the Northwestern Gulf of Mexico from 2-D Multichannel Seismic Data

Lewis, Dan'L 1986- 14 March 2013 (has links)
This study was undertaken to investigate mobile salt and its effect on fault structures and gas hydrate occurrence in the northwestern Gulf of Mexico. Industry 2-D multichannel seismic data were used to investigate the effects of the salt within an area of 7,577 mi^2 (19,825 km^2) on the Texas continental slope in the northwestern Gulf of Mexico. The western half of the study area is characterized by a thick sedimentary wedge and isolated salt diapirs whereas the eastern half is characterized by a massive and nearly continuous salt sheet topped by a thin sedimentary section. This difference in salt characteristics marks the edge of the continuous salt sheets of the central Gulf of Mexico and is likely a result of westward decline of original salt volume. Beneath the sedimentary wedge in the western part of the survey, an anomalous sedimentary package was found, that is described here as the diapiric, gassy sediment package (DGSP). The DGSP is highly folded at the top and is marked by tall, diapiric features. It may be either deformed shale or the toe of a complex thrust zone detaching the sedimentary wedge from deeper layers. The dataset was searched for the occurrence of bottom simulating reflectors (BSRs), as they are widely accepted as a geophysical indicator of gas trapped beneath gas hydrate deposits, which are known to occur farther east in the Gulf. Although, many seismic signatures were found that suggest widespread occurrence of gas within the upper sediment column, few BSRs were found. Even considering non-traditional definitions of BSRs, only a few occurrences of patchy and isolated BSRs features were identified. The lack of traditional BSRs is likely the result of geologic conditions that make it difficult to recognize gas hydrate deposits. These factors include: (1) unfavorable layer geometries, (2) flow of warm brines from depth, (3) elevated geotherms due to the thermogenic properties of salt and its varying thickness, and (4) widespread low porosity and permeability sediments within the gas hydrate stability zone.
143

Functionality based refactoring : improving source code comprehension

Beiko, Jeffrey Lee 02 January 2008 (has links)
Software maintenance is the lifecycle activity that consumes the greatest amount of resources. Maintenance is a difficult task because of the size of software systems. Much of the time spent on maintenance is spent trying to understand source code. Refactoring offers a way to improve source code design and quality. We present an approach to refactoring that is based on the functionality of source code. Sets of heuristics are captured as patterns of source code. Refactoring opportunities are located using these patterns, and dependencies are verified to check if the located refactorings preserve the dependencies in the source code. Our automated tool performs the functional-based refactoring opportunities detection process, verifies dependencies, and performs the refactorings that preserve dependencies. These refactorings transform the source code into a series of functional regions of code, which makes it easier for developers to locate code they are searching for. This also creates a chunked structure in the source code, which helps with bottom-up program comprehension. Thus, this process reduces the amount of time required for maintenance by reducing the amount of time spent on program comprehension. We perform case studies to demonstrate the effectiveness of our automated approach on two open source applications. / Thesis (Master, Computing) -- Queen's University, 2007-10-05 12:48:56.977
144

The Relationship Between Bottom-Up Saliency and Gaze Behaviour During Audiovisual Speech Perception

Everdell, IAN 12 January 2009 (has links)
Face-to-face communication is one of the most natural forms of interaction between humans. Speech perception is an important part of this interaction. While speech could be said to be primarily auditory in nature, visual information can play a significant role in influencing perception. It is not well understood what visual information is important or how that information is collected. Previous studies have documented the preference to gaze at the eyes, nose, and mouth of the talking face, but physical saliency, i.e., the unique low-level features of the stimulus, has not been explicitly examined. Two eye-tracking experiments are presented to investigate the role of physical saliency in the guidance of gaze fixations during audiovisual speech perception. Experiment 1 quantified the physical saliency of a talking face and examined its relationship with the gaze behaviour of participants performing an audiovisual speech perception task and an emotion judgment task. The majority of fixations were made to locations on the face that exhibited high relative saliency, but not necessarily the maximally salient location. The addition of acoustic background noise resulted in a change in gaze behaviour and a decrease in correspondence between saliency and gaze behaviour, whereas changing the task did not alter this correspondence despite changes in gaze behaviour. Experiment 2 manipulated the visual information available to the viewer by using animated full-feature and point-light talking faces. Removing static information, such as colour, intensity, and orientation, from the stimuli elicited both a change in gaze behaviour and a decrease in correspondence between saliency and gaze behaviour. Removing dynamic information, particularly head motion, resulted in a decrease in correspondence between saliency and gaze behaviour without any change in gaze behaviour. The results of these experiments show that, while physical saliency is correlated with gaze behaviour, it cannot be the single factor determining the selection of gaze fixations. Interactions within and between bottom-up and top-down processing are suggested to guide the selection of gaze fixations during audiovisual speech perception. / Thesis (Master, Neuroscience Studies) -- Queen's University, 2008-12-18 13:10:01.694
145

The marine geology of the Northern KwaZulu-Natal continental shelf, South Africa.

Green, Andrew Noel. January 2009 (has links)
This study proposes that the submarine canyons of the northern Kwazulu-Natal continental margin formed contemporaneously with hinterland uplift, rapid sediment supply and shelf margin progradation during the forced regression of upper Miocene times. These forced regressive systems tract deposits volumetrically dominate the shelf sediments, and comprise part of an incompletely preserved sequence, amongst which six other partially preserved sequences occur. The oldest unit of the shelf corresponds to forced regression systems tract deposits of Late Cretaceous age (seismic unit A), into which a prominent erosive surface, recognized as a sequence boundary, has incised. Fossil submarine canyons are formed within this surface, and underlie at least one large shelf-indenting canyon in the upper continental slope. Smaller shelf indenting canyons exhibit similar morphological arrangements. Late Pliocene deposits are separated from Late Cretaceous lowstand deposits (seismic unit B) by thin veneers of Late Palaeocene (seismic unit C) and mid to early Miocene (seismic unit D) transgressive systems tract deposits. These are often removed by erosive hiatuses of early Oligocene and early to mid Pliocene age. These typically form a combined hiatus surface, except in isolated pockets ofthe upper slope where late Miocene forced regressive systems tract units are preserved (anomalous progradational seismic unit). These sediments correspond to the regional outbuilding of the bordering Tukhela and Limpopo cones during relative sea level fall. Either dominant late Pliocene sediments (seismic unit E), or transgressive systems tract sediments which formed prior to the mid Pliocene hiatus, overlie these sediments. Widespread growth faulting, slump structures and prograding clinoforms towards canyon axes indicate that these sediments initiated upper slope failure which served to create proto-canyon rills from which these canyons could evolve. The association of buried fossil canyons with modern day canyons suggests that the rilling and canyon inception process were influenced by palaeotopographic inheritance, where partially infilled fossil canyons captured downslope eroding flow from an unstable upper slope. Where no underlying canyons occur, modern canyons evolved from a downslope to upslope eroding system as they widened and steepened relative to the surrounding slope. Statistical quantification of canyon forms shows a dominance of upslope erosion. Landslide geomorphology and morphometric analysis indicate that this occurred after downslope erosion, where the canyon axis was catastrophically cleared and incised, leading to headward retreat and lateral excavation of the canyon form. Trigger mechanisms for canyon growth and inception point to an overburdening ofthe upper slope causing failure, though processes such as freshwater sapping may emulate this pattern of erosion. It appears that in one instance, Leven Canyon, freshwater exchange with the neighbouring coastal waterbodies has caused canyon growth. The canyons evolved rapidly to their present day forms, and have been subject to increasingly sediment starved conditions, thus limiting their evolution to true shelf breaching canyon systems. Sedimentological and geomorphological studies show that the shelf has had minor fluvial influences, with only limited shelf-drainage interaction having occurred. This is shown by isolated incised valleys of both Late Cretaceous and Late PleistocenelHolocene age. These show classic transgressive valley fills of wave dominated estuaries, indicating that the wave climate was similar to that of today. The narrowness of the shelf and the inheritance of antecedent topography may have been a factor in increasing the preservation potential of these fills. Canyons thus appear to have been "headless" since their inception, apart from Leven Canyon, which had a connection to the Last Glacial Maximum (LGM) St Lucia estuary, and Wright Canyon, which had an ephemeral, shallow LGM channel linking it to the Lake Sibaya estuarine complex. Coastline morphology has been dominated by zeta bays since at least 84 000 BP, thus littoral drift has been limited in the study area since these times. The formation of beachrock and aeolianite sinks during regression from the last interstadial has further reduced sediment supply to the shelf. The prevalence of sea-level notching in canyon heads, associated with sea levels of the LGM indicates that canyon growth via slumping has been limited since that time. Where these are obscured by slumping in the canyon heads (Diepgat Canyon), these slumps have been caused by recent seismic activity. The quiescence of these canyons has resulted in the preservation of the steep upper continental slope as canyon erosion has been insufficient to plane the upper slope to a uniform linear gradient such as that of the heavily incised New Jersey continental margin. Progressive sediment starvation of the area during the Flandrian transgression has resulted in a small shore attached wedge of unconsolidated sediment (seismic unit H) being preserved. This is underlain by a mid-Holocene ravinement surface. This crops out on the outer shelf as a semi-indurated, bioclastic pavement. Thinly mantling this surface are Holocene sediments which have been reworked by the Agulhas Current into bedforms corresponding to the flow regime and sediment availability to the area. Bedforms are in a state of dis-equilibrium with the contemporary hydrodynamic conditions, and are presently being re-ordered. It appears that sediment is not being entrained into the canyons to the extent that active thalweg downcutting is occurring. Off-slope sediment loss occurs only in localized areas, supported by the dominance of finer grained Early Pleistocene sediments of the outer slope. A sand ridge from the mid shelf between Wright and White Sands Canyons appears to have been a palaeo-sediment source to White Sands Canyon, but is currently being reworked southwards towards Wright Canyon. The prevalence of bedform fields south of regularly spaced canyon heads is considered a function of hydrodynamic forcing of the Agulhas Current by canyon topography. These bedforms are orientated in a northerly direction into the canyon heads, a result ofnortherly return eddying at the heads of these canyons. / Thesis (Ph.D.)-University of KwaZulu-Natal, Westville, 2009.
146

Collaboration Between Sectors for Social Innovation : The Refugee Housing Unit Case

Macharia, Dorothy, Garcia, Daniel January 2014 (has links)
Background: Events happening in the 21st century- global economic crisis, naturaldisasters, extreme poverty, struggles and conflicts have led to a realization that we areliving in a troubled world where we are interdependent in one way or the other. These issues tend to be complex and intertwined such that delegating them to a single sectoris too huge of a task to bear, thus the need for social innovation through cross sector collaboration. The case of the Refugee Housing Unit is being studied- a collaboration between the IKEA Foundation, UNHCR and the Swedish Industrial Design Foundation led to the creation of a more sustainable environmental friendly shelter for refugees.Since social innovation is a green field especially in a BOP context, the research is aimed at understanding how the RHU case can provide important insight in which collaboration theory can be applied between sectors to shape future social innovation endeavors. Aim: The aim of this thesis is to study the collaboration of organizations belonging to different sectors to create social innovations. This research will examine how collaboration between sectors takes place, and through the empirical case of theRefugee Housing Unit, derive key learning points that could shape future social innovation projects. A framework will be developed that could provide important insightsfor future socially oriented collaborations. Methodology: The proposed framework was developed through a study of socialinnovation theory in terms how it can be accelerated through cross sector collaborationiitheory. A case study that entailed these two theories was chosen to enable the development of a suggested framework. The study involved collection of primary data inform of interviews with Johan Karlsson and Chris Earney, RHU project leader and UNHCR Innovation co-leader, respectively. Additionally, secondary data was used tohelp understand the case further. Results: Examining the core elements of cross-sectoral collaboration for social innovation showed imperative social aspects as well as key dimensions that are pillars for the process of collaboration. The RHU case revealed critical factors for collaboration between sectors that are well stipulated in the framework. The framework can act as a guide for organizations wishing to collaborate for social innovation as well as provide abasis for future research in this young field.
147

Hållbarhetsredovisning och dess användbarhet : En studie ur svenska kreditgivares perspektiv

Bredbacka, Christoffer, Ölmhagen, Oskar January 2014 (has links)
Bakgrund: Hållbarhetsredovisningar har blivit allt mer populära på senare tid. Genom dessa kommunicerar företaget ut till sina intressenter om verksamhetens påverkan på samhället ur ett hållbarhetsperspektiv. Tidigare forskning har till stor del koncentrerat sig på företagens perspektiv och vilken nytta de har av hållbarhetsredovisningar, men det finns även en mottagande sida av kommunikationen som utgörs av företagens intressenter. Bland intressenterna finns det ett forskningsgap om hur kreditgivarna uppfattar hållbarhetsredovisningarna, trots att de är en av de viktigaste intressentgrupperna. Forskning med utgångspunkt i legitimitetsteorin och signaleringsteorin, har även visat att den nytta företagen har av hållbarhetsredovisningarna kan ske på bekostnad av hållbarhetsredovisningarnas användbarhet ur kreditgivarnas perspektiv.   Syfte: Syftet med studien är att undersöka hur användbara hållbarhetsredovisningar är för svenska kreditgivare, samt att bidra till diskussionen i forskningen kring hållbarhetsredovisningens användbarhet utifrån hur den ser ut idag. Studien har även som delsyften att skapa en djupare förståelse för varför det ser ut som det gör, samt att bidra med underlag, dels till företag hur de ska bedriva sin hållbarhetsredovisning med kreditgivare i åtanke, men även till standardsättare vid utveckling av ramverk för hållbarhetsredovisning.   Teoretisk utgångspunkt: Arbetet innehåller en referensram som innefattar ämnen som hållbarhetsredovisning, kvaliteten på informationen, extern granskning och kreditgivning. Arbetet innehåller också en teoridel där vi tar upp intressentteorin, legitimitetsteorin, signaleringsteorin och Carrolls CSR pyramid.   Metod: För att besvara syftet med studien har vi använt oss av en kvalitativ metod med semistrukturerade intervjuer. Det empiriska materialet består av sju intervjuer med åtta personer som arbetar med kreditgivning till företag. Studien är gjord ur en hermeneutisk synvinkel där fokus har legat på att tolka respondenternas uppfattning av hållbarhetsredovisningarnas användbarhet utifrån intervjuerna.   Resultat och slutsatser: Studien visade att det finns individuella skillnader kreditgivarna emellan om vilket behov av hållbarhetsrelaterad information de har och det varierar därför hur användbara hållbarhetsredovisningarna är från kreditgivare till kreditgivare. Informationsbehovet för de individuella kreditgivarna visades i sin tur kunna bero på vilken nivå av ansvarstagande de befinner sig på, storleken på de lån och kunder de kommer i kontakt med, samt på vilken bransch deras kunder är verksamma inom. Vi kom fram till att kreditgivarna uppfattade att det finns utrymme för förbättring vad gäller kvaliteten på hållbarhetsredovisningarna. Utifrån de samhällsekonomiska teorierna fann vi att kritiken mot hållbarhetsredovisningarnas kvalitet kan bero på att de riktar sig till flera intressenter och inte bara kreditgivare samt misstanken om att företag använder hållbarhetsredovisningarna av strategiska orsaker. Vi kom dock fram till att hållbarhetsredovisningarna håller en tillräckligt god kvalitet för att kreditgivarna ska kunna ha användning av dem. Däremot visade studien att kreditgivarna föredrog att inhämta informationen genom personlig kontakt med företaget framför hållbarhetsredovisningarna, vilket kan förklaras av kreditgivarnas interna struktur och redovisningsmiljön.
148

A critical analysis of global sustainability indices / Brian Neville Keeling

Keeling, Brian Neville January 2013 (has links)
Nation states of the world are driven by socio-economic imperatives that are rapidly degrading the natural resources that sustain life on Earth. This paradox has led to numerous initiatives to better understand and measure sustainability and sustainable development through indices. The primary objective of this research is to critically analyse the plethora of indices developed and used by institutions and organisations globally that have a role to play in measuring the sustainability and sustainable development of nation states, and distil the analysis into one integrated Sustainable Development Index (SDI) that compares all countries. A secondary objective is to review South Africa‟s response to measure sustainability and determine how well it performs compared to other nation states. A qualitative approach is used to review the literature in three steps, namely to consider the challenges of measuring what matters, to reflect on the response to govern and measure sustainability, and then to identify outcomes in terms of specific indices related to triple bottom line dimensions. The review considers the scope and level of integration of global indices as well as South Africa‟s response to measure sustainability. The analysis phase normalizes all the data to establish an integrated SDI for all countries, it then analyses and interprets the data to determine the variation and correlation between all the global indices, and then benchmarks countries and specifically South Africa. The review finds that twenty-one years after the Agenda 21 agreement at the Rio Earth Summit, no acceptable or established SDI has been developed and implemented by the United Nations, and the analysis develops two options for an integrated SDI at nation state level. In terms of both these SDI‟s South Africa performs poorly from a benchmarked perspective. From both the nation state and global indices perspectives, the appraisal of the single integrated SDI finds significant variations in the results, coupled with a wide range of correlation outcomes which distil into well correlated single integrated SDIs. The findings indicate that recent SDI developments are moving towards human wellbeing indicators, however although environmental priorities are considered, they play a secondary role. This “inconvenient truth” alludes to a “business as usual” approach as the policy makers of the world continue to focus on short-term socio-economic imperatives. Environmental thresholds and “limits to growth” considerations need to be fundamental aspects of all SDIs. This argument continues by factoring thresholds and priorities into the triple bottom line dimensions - a Sustainability Intelligence Quotient is developed from the integrated SDI, which suggests that only two countries meet the requirements. / (Master of Environmental Management), North-West University, Potchefstroom Campus, 2013
149

A critical analysis of global sustainability indices / Brian Neville Keeling

Keeling, Brian Neville January 2013 (has links)
Nation states of the world are driven by socio-economic imperatives that are rapidly degrading the natural resources that sustain life on Earth. This paradox has led to numerous initiatives to better understand and measure sustainability and sustainable development through indices. The primary objective of this research is to critically analyse the plethora of indices developed and used by institutions and organisations globally that have a role to play in measuring the sustainability and sustainable development of nation states, and distil the analysis into one integrated Sustainable Development Index (SDI) that compares all countries. A secondary objective is to review South Africa‟s response to measure sustainability and determine how well it performs compared to other nation states. A qualitative approach is used to review the literature in three steps, namely to consider the challenges of measuring what matters, to reflect on the response to govern and measure sustainability, and then to identify outcomes in terms of specific indices related to triple bottom line dimensions. The review considers the scope and level of integration of global indices as well as South Africa‟s response to measure sustainability. The analysis phase normalizes all the data to establish an integrated SDI for all countries, it then analyses and interprets the data to determine the variation and correlation between all the global indices, and then benchmarks countries and specifically South Africa. The review finds that twenty-one years after the Agenda 21 agreement at the Rio Earth Summit, no acceptable or established SDI has been developed and implemented by the United Nations, and the analysis develops two options for an integrated SDI at nation state level. In terms of both these SDI‟s South Africa performs poorly from a benchmarked perspective. From both the nation state and global indices perspectives, the appraisal of the single integrated SDI finds significant variations in the results, coupled with a wide range of correlation outcomes which distil into well correlated single integrated SDIs. The findings indicate that recent SDI developments are moving towards human wellbeing indicators, however although environmental priorities are considered, they play a secondary role. This “inconvenient truth” alludes to a “business as usual” approach as the policy makers of the world continue to focus on short-term socio-economic imperatives. Environmental thresholds and “limits to growth” considerations need to be fundamental aspects of all SDIs. This argument continues by factoring thresholds and priorities into the triple bottom line dimensions - a Sustainability Intelligence Quotient is developed from the integrated SDI, which suggests that only two countries meet the requirements. / (Master of Environmental Management), North-West University, Potchefstroom Campus, 2013
150

Continental shelf sediments, Columbia River to Cape Blanco, Oregon

Runge, Erwin John 01 December 1965 (has links)
Sediments on the inner portion of the Oregon continental shelf consist of clean, well-sorted, detrital sand. This sand has an average median diameter of 2.53Φ (. 173 mm) and is both positively and negatively skewed. Deposits with median diameters in the coarse sand and gravel classes occur at depths of 20 to 40 fathoms and probably represent ancient beach or fluviatile deposits formed during lower stands of sea level. The outer shelf and upper slope are covered by poorly sorted sediments with median diameters in the fine sand to fine silt classes. Mean diameters of the sediments are almost always smaller than their median diameters and the sediments are positively skewed. The heavy mineral assemblages are dominated by the amphibole and pyroxene groups and the opaque-garnet association. Pyroxenes are most abundant in the coarser-grained sediments of the inner shelf and decrease in abundance offshore. Amphiboles are most abundant in the finer-grained sediments of the outer shelf and upper slope. Highest concentrations of the opaque-garnet association also are found in the inshore samples. Sediments of the continental shelf are derived from two principal sources, rivers and erosion of coastal terrace deposits. Rivers are probably contributing only fine-grained material to the shelf as much of the coarser fluviatile material is thought to be trapped in the estuaries. The terrace deposits are actively being eroded and are thought to contribute about 21,000,000 cubic feet (.00013 cubic miles) of sediment to the continental shelf annually. Evidence suggests that much of the inner-shelf sand is probably a relict transgressive sheet sand that was deposited during the last rise in sea level. Most of the deposition of the modern sand on the shelf has been confined to the inner portion of the inner shelf. Finer-grained sediments have been deposited on the outer shelf and upper slope. Characteristics of the sediments on the present continental shelves may be useful in identifying continental shelf deposits in the geologic column. / Graduation date: 1966

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