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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.
21

Evaluation of Dechlorinating Agents and Disposable Containers for Odor Testing of Drinking Water

Worley, Jennifer Lee 08 September 2000 (has links)
As the bottled water trend continues to rise across the nation, drinking water utilities have become more concerned with ensuring consumer satisfaction of their product. Although public water supplies are safeguarded by regulations, aesthetically unappealing taste-and-odor problems have led consumers to search for alternative water sources, such as bottled water or tap water processed by point-of-use filters. Consequently, taste-and-odor monitoring has become important to the drinking water industry. Because many utilities use chlorine to disinfect the water, chlorine odor often masks other more subtle odors that may eventually cause consumer complaints. As treated water travels from the water treatment plant to the consumer, chlorine residual diminishes and may reveal a water's naturally less-pleasing odors. Consequently, odor monitoring at the water treatment plant, where chlorine concentrations are at a peak, may not identify potential displeasing smells. Proper evaluation of these odor-causing substances requires that the chlorine odor first be eliminated before evaluating any remaining odors. Dechlorinating agents can remove chlorine, but some will produce other unwanted odors or even remove certain odorous compounds. This research describes the efficiency of several of these agents (ascorbic acid, hydrogen peroxide, oxalic acid, sodium nitrite, and sodium thiosulfate) in dechlorinating chlorinated solutions of the earthy-smelling compound geosmin and musty-smelling MIB. Interfering odors in reusable containers pose another problem in drinking water odor analysis. The most common odor-analysis methods (TON and FPA) involve the use of glass flasks, which often either develop chalky odors or have persistent lingering odors from previous evaluations. Furthermore the glass flasks break easily and are difficult to clean. This research also evaluates the suitability of four types of disposable plastic containers for odor analyses. / Master of Science
22

LEARNING GRASP POLICIES FOR MODULAR END-EFFECTORS OF MOBILE MANIPULATION PLATFORMS IN CLUTTERED ENVIRONMENTS

Juncheng Li (18418974) 22 April 2024 (has links)
<p dir="ltr">This dissertation presents the findings and research conducted during my Ph.D. study, which focuses on developing grasp policies for modular end-effectors on mobile manipulation platforms operating in cluttered environments. The primary objective of this research is to enhance the performance and accuracy of robotic manipulation systems in complex, real-world scenarios. The work has potential implications for various domains, including the rapidly growing Industry 4.0 and the advancement of autonomous systems in space habitats.</p><p dir="ltr">The dissertation offers a comprehensive literature review, emphasizing the challenges faced by mobile manipulation platforms in cluttered environments and the state-of-the-art techniques for grasping and manipulation. It showcases the development and evaluation of a Modular End-Effector System (MEES) for mobile manipulation platforms, which includes the investigation of object 6D pose estimation techniques, the generation of a deep learning-based grasping dataset for MEES, the development of a suction cup gripper grasping policy (Sim-Suction), the development of a two-finger grasping policy (Sim-Grasp), and the integration of Modular End-Effector System grasping policy (Sim-MEES). The proposed methodology integrates hardware designs, control algorithms, data-driven methods, and large language models to facilitate adaptive grasping strategies that consider the unique constraints and requirements of cluttered environments.</p><p dir="ltr">Furthermore, the dissertation discusses future research directions, such as further investigating the Modular End-Effector System grasping policy. This Ph.D. study aims to contribute to the advancement of robotic manipulation technology, ultimately enabling more versatile and robust mobile manipulation platforms capable of effectively interacting with complex environments.</p>
23

Friction and lubrication behaviour of metal-on-metal and ZTA ceramic-on-CFR PEEK hip prostheses : friction and lubrication behaviour of metal-on-metal hip resurfacing and ZTA ceramic heads versus CFR PEEK cups with various diameters and clearances using serum-based lubricants with various viscosities

Said, Assma Musbah January 2012 (has links)
The natural hip joint in healthy people has a very low friction with very little (or no) wear. It works as a dynamically loaded bearing and is subjected to about 1-2 million cycles of loading per year. The applied load is the body weight which is tripled when walking and even higher during other activities such as running and jumping. Unfortunately these joints are not always healthy due to various causes such as fractures or disease leading to severe pain which necessitates joint replacement. Currently, the orthopaedic industries are working towards developing an ideal artificial hip joint with low wear, low friction, good lubrication, better fixation/stability and biocompatibility. Many different designs and materials have been investigated with some promising new implants which can be used depending on patients' individual need (large or small joint), activity and age. In this work, two types of artificial hip joints were tested for friction and lubrication studies: Metal-on-Metal (MoM) Biomet hip resurfacing ReCaps with large diameters (>35-60 mm) and different diametral clearances (~ 60-350 µm), and Zirconia Toughened Alumina (ZTA) heads against carbon-fibre-reinforced poly-ether-ether ketone (CFR PEEK) cups with different diameters (>35-60 mm) and diametral clearances (60-1860 µm). Seven serum-based lubricants with different viscosities were used with and without carboxy methyl cellulose (CMC) additions as gelling agent to increase viscosity depending on the CMC content. The maximum load applied was 2000 N for the stance phase with a minimum load of 100 N for the swing phase. A Pro-Sim friction hip simulator was used to investigate the frictional torque generated between the articulating surfaces so as the friction factor can be calculated. Stribeck analysis was then employed to assess the mode of lubrication. For the metal-on-metal hip resurfacing joints, the friction factors were in the range 0.03-0.151 and those for the ZTA ceramic heads versus CFR PEEK cups were in the range 0.006-0.32. Stribeck analyses showed mainly mixed lubrication for both MoM and ZTA ceramic-on-CFR PEEK joints. The experimental results were in agreement with most of the theoretical calculations suggesting mixed lubricating regimes at low viscosities and moving on to fluid film lubrication at higher viscosities. Joints with larger-diameters, lower clearances and lower surface roughness exhibited a higher lambda ratio suggesting improved lubrication. Viscosity flow curves for the serum-based lubricants having viscosity ≤ 0.00524 Pas showed non-linear relationship between viscosity and shear rate indicating non-Newtonian flow with pseudoplastic or shear-thinning characteristic, i.e. viscosity decreased as shear rate increased up to shear rates of ~ 1000 s⁻¹. However, at shear rates greater than 1000 s⁻¹ Newtonian flow became dominant with almost constant viscosity, i.e. a linear relationship between shear stress and shear rate. On the other hand, viscosity flow curves for the lubricants with viscosity ≥ 0.0128 Pas showed non-Newtonian behaviour up to a shear rate of 3000 s⁻¹ with shear-thinning characteristic.
24

Friction and lubrication behaviour of hip resurfacing metal-on-metal and ZTA ceramic on CFR peek implants with various diameters and clearances : friction and lubrication behaviour of hip resurfacing Co-Cr-Mo and zirconia toughened alumina ceramic heads against carbon fibre reinforced poly-ether-ether-ketone cups with various diameters and clearances have been investigated using serum-based lubricants

Ehmaida, Mutyaa M. January 2012 (has links)
Total hip joint prostheses made of CoCrMo heads versus ultra high molecular weight polyethylene (UHMWPE) cups have a limited lifetime, mainly due to the wear of the UHMWPE cups as a result of high friction between the articulating surfaces leading to osteolysis and implant loosening with revision surgery becoming inevitable in more active patients. Tribology plays an important role in developing the design, minimizing wear and reducing friction of hip joint prostheses in order to improve their long-term performance, with good lubricating properties. Metal-on-metal hip resurfacing prostheses have shown significantly lower wear rates compared with conventional metal-on-polyethylene implants and thus osteolysis is potentially reduced leading to increased lifetime of the prosthesis. Nevertheless, excessive wear of metal-on-metal joints leads to metal ion release, causing pseudo-tumours and osteolysis. An alternative approach to such bearings is the use of newly developed carbon fiber-reinforced poly-ether-ether-ketone (CFR PEEK) acetabular cups articulating against ceramic femoral heads due to their better wear resistance compared to UHMWPE. In this study, therefore, friction and lubrication properties of large diameter, as cast, Co-Cr-Mo metal-on-metal hip resurfacing implants with various diameters and clearances have been investigated and compared to those of the newly developed zirconia toughened alumina (ZTA) ceramic femoral heads articulating against carbon fiber reinforced poly-ether-ether-ketone (CFR PEEK) acetabular cups with different diameters and clearances. Friction hip simulator was used to measure frictional torque and then friction factors were calculated along with Sommerfeld numbers leading to Stribeck analysis and hence the lubricating mode was also investigated. This involved using lubricants based on pure bovine serum (BS) and diluted bovine serum (25 vol. %BS+75 vol. %distilled water) with and without carboxymethyl cellulose (CMC) (as gelling agent). Standard Rheometer was used to measure lubricant viscosity ranged from 0.0014 to 0.236 Pas at a shear rate of 3000 . Pure bovine serum, diluted bovine serum without CMC and with CMC (25BS+75DW+0.5gCMC and +1gCMC) showed pseudoplastic flow behaviour up to shear rate of ~139 s⁻¹ above which a Newtonian flow with significant increase in shear stress was observed. The viscosity flow curves for the 25BS+75DW+2gCMC, +3.5gCMC and +5gCMC showed only shear thinning up to a shear rate of 3000 . The shear rate application modified the flow behaviour of bovine serum from a pseudoplastic to a Newtonian flow depending on its purity and CMC content. This will cause a different frictional behaviour depending on joint diameter and clearance, as seen in this work. The experimental data were compared with theoretical iv predictions of the lubricating regimes by calculating theoretical film thickness and lambda ratio. The metal-on-metal Biomet ReCaps showed similar trends of Stribeck curves, i.e. friction factors decreased from ~0.12 to ~0.05 as Sommerfeld numbers increased in the range of viscosities ~0.001-0.04Pas indicating mixed lubrication regimes above which the friction factor increased to ~0.13 at a viscosity of 0.236Pas. The Stribeck analyses suggested mixed lubrication as the dominant mode with the lowest friction factor in the range ~0.09 - ~0.05 at the physiological viscosities of ~0.01 to ~0.04 Pas and that such joints can be used for more active patients as compared to the conventional total hip replacement joints with 28mm diameter. The Stribeck curves for all ZTA ceramic-on-CFR PEEK components illustrated a similar trend with BS fluids showing higher friction factors (in the range 0.22-0.13) than the diluted BS+CMC fluids (in the range 0.24-0.05). The friction tests revealed boundary-mixed lubrication regimes for the ZTA ceramic-on-CFR-PEEK joints. The results, so far, are promising and suggest clearly that the newly developed ZTA ceramic femoral heads articulating against CFR PEEK cups have similar friction and lubrication behaviour at optimum clearances to those of currently used metal-onmetal hip resurfacing implants at the range of viscosities 0.00612 to 0.155Pas. These results clearly suggest that the ZTA ceramic-on-CFR-PEEK joints showed low friction at the physiological viscosities of ~0.01Pas in the range ~0.1-0.05, suggesting that these novel joints may be used as an alternative material choice for the reduction of osteolysis. The result of this investigation has suggested that the optimum clearance for the 52mm diameter MOM Biomet ReCaps could be ~170μm. However, 48 and 54mm joints showed lower friction due to clearances to be >200μm. For the 52mm ZTA ceramic-on-CFR-PEEK joints the optimum clearance seems to be ≥ 630μm radial clearance. These results suggested that increased clearance bearings have the potential to generate low friction and hence no risk of micro- or even macro-motion for the ceramic-on-CFR-PEEK joints. This study found no correlation between theoretical predictions and experimental data for all metal-onmetal and ZTA ceramic-on-CFR PEEK bearings at the physiological viscosity (0.0127Pas). However, at lubricant viscosity of 0.00157Pas, the theoretical prediction of lubrication regime correlated well with the experimental data, both illustrating boundary lubrication. As expected, a decrease in viscosity resulted decrease in the film thickness.
25

"Throw Me Something, Mister": The History of Carnival Throws in New Orleans

Capo, Lissa 20 May 2011 (has links)
Mardi Gras draws millions of tourists to New Orleans yearly, contributing to the economy of the city. Visitors soon discover the thrill of catching "throws" tossed to paradegoers by members of parade organizations' riding floats. For tourists and locals alike, throws become the cultural currency of New Orleans during Carnival. Beads, doubloons, coconuts, cups and other throws develop an inherent value, enticing crowds. People esteem throws enough to compete for them, with varying levels of intensity, along parade routes and on the streets of the French Quarter. The purchase of throws by Carnival krewes also brings revenue into New Orleans. Scholars have written many studies on Mardi Gras, including studies on individual organizations, tourism and economy. However, no study examines the history of Mardi Gras throws. This thesis seeks to fill that void, and establishes an earlier date for the first time beads were thrown from floats.
26

Significance, the vessel and the domestic

Brown, Sandra Lois, School of Design, UNSW January 2004 (has links)
Throughout history, people have made or acquired vessels from which to sip their favourite beverage. In the contemporary domestic setting, households frequently accumulate multiples of the same type of object in numbers that are considerably greater than is necessary and practical for use alone. Of these many objects there are often individual pieces that have special significance for the owner or user. Some are so valued that they may even be removed and set aside because of their perceived importance. The research was initiated by a previous study of tea drinking vessels coupled with a desire, as an object maker and collector, to find out why people have special items that they designate as personally important. The aim was to identify how significance could be recognised in specific objects and whether the notion that a group of features used to gauge such objects could be conveyed into studio based work. The research outcomes are evidenced in a text-based document (which articulates the theoretical and empirical elements of the enquiry) and a body of creative studio work developed in response to aspects of the investigation. The document encompasses two components of the study. The first references material from the fields of museum and cultural studies, pivotal in focusing the enquiry. This contributed to the compilation of a general and speculative inventory of qualities that might pertain to objects deemed ???significant???. During these early investigations it became evident that a more in depth and contemporary analysis of significant drinking vessels, their owners and/or users was required. A Survey Questionnaire regarding personal use and special drinking vessels preceded a series of Interviews with a selected group of Australia curators, artists, academics and collectors who discussed and analysed their association with a personally significant drinking vessel. Subsequently, the content of these interviews became central to the focus of the research and outcomes. The research isolates a number of attributes that are commonly identified in objects that, whatever their condition, are deemed ???significant???. These describe the maker, usage, ownership, association and historical context. The perceived value or worth of the object for its owner, is recognised as a consequence of significance and declares the object as distinctive. This outcome is clearly validated by the interviews. The studio work develops from the fusion of personal narrative that has been enhanced by findings of the research. In particular, it references the cherished object, most especially those pieces that have been retained despite the ravages of time and use. The resulting work was exhibited as Trace Elements ??? Marking Time: Significance, the Vessel and the Domestic at Kudos Gallery, Paddington in April 2004.
27

Design &amp; Narration? : -A research exploring how design and narration, collectively, work as a means to expand the uncharted field of design pedagogy / Design &amp; Narration? : En undersökning som utforskar hur design och berättande, kollektivt, fungerar som redskap i arbetet med att vidga fältet för designpedagogik.

Ceder, Clara January 2011 (has links)
ABSTRACT This text process a design pedagogical research executed in Arvidsjaur during the fall of 2011. The formulation of questions that this study circles around regards how combining design and narration can be used in the development of design pedagogy. Also scrutinized, how did the formulation of this research affect the outcome and what means, in addition their attendance, did the people who partook contribute with?    The purpose is to find a pedagogic angle that moves focus away from the finished product and onto other aspects of the design process. To clarify, by investigating how narration adapts as a tool during a design process this research seek to enlighten ways that we comprehend, and make use of, our surroundings while working towards a common - designed - goal. What comes about when gathering a group of people and asking them to represent Arvidsjaur by designing a cup? The material used emanates from observations, narratives, images and finished artifacts – all deriving from a set of workshops held in the city of Arvidsjaur. To partake in the workshops was voluntary and the invite began with the question/statement: Design and narration? An ethnographically inspired method preceded the structure of the study and hence made it impossible to foreordain what would occur before arriving in Arvidsjaur. By placing the gathered material and observations along with a set of selected theories, such as sociocultural learning and social constructionism, I wish to enlighten and point out qualities, along with weaknesses, that this study occupies.  Beyond a written contribution, and the work on the field, the research resulted in a number of designed cups. These cups were photographed, processed, and depicted in three different ways – as posters and as a series of photographs. These images were on display during an exhibition at Konstfack in December 2011. My contribution to the exhibition was meant as a continuation on questions regarding design and narration. What happens e.g. with an item when it is displayed in this matter? When moved from one context to another? It is thus a way to stress the importance of questioning and challenge the way we apprehend our surroundings and what we chose to enlighten or leave out – a comment on a stirring development. I did not wish to explain to the viewer what the cups narrate; they were made to reveal something on their own. How they ultimately are received becomes yet another way of pointing out that how we experience something is dependent on a variety of circumstances.
28

Sola scriptura : die Skrifbeskouing in die Gereformeerde Kerke van Suid-Afrika sedert 1959 : ʼn dogmaties-historiese ondersoek / Christiaan Jooste

Jooste, Christiaan January 2011 (has links)
In the history of the Reformed Churches of South Africa (RCSA) great emphisis was placed on the notion to make decisions on the basis, and in accordance to the Scriptures. In spite of this notion, the church community of the RCSA stand in the midst of great tension regarding some decisions. In the fifty year period from the centenary festival in 1959 to the 150 year festival in 2009, assemblies of the church community were confronted with many objections to decisions regarding racial relations, the acceptance of the 1983-translation of the Bible in Afrikaans, the acceptance of the 2001-Psalter, the use of small cups in the Holy Communion and the role of women in the offices of deacon, elder and minister. The question that’s being addressed in this study is, if a shift in the RCSA’s view of Scripture took place. Chapter 2 gives an historical overview of the decisions that gave way to to the differences mentioned above. From the historical overview the aspects regarding the view of Scripture can be formulated. In chapter 3 the relation between the differences and the view of Scripture are examined. At first a short definition of the reformed view of Scripture are formulated. Hermeneutical and view of Scripture aspects of the raports of deputies and decisions of assemblies are tested according to the formulated definition of a reformed view of Scripture. Chapter 4 examines the influence that paradigm shifts had on the differences in the RCSA. Focus is placed on the influence of postmodernism on the one hand and fundamentalism on the other. Attention is also given to the stance of the RCSA on these two paradigms of thought with relation to the view of Scripture. In light of the reformed view of Scripture the postmodern approach to hermeneutics is discarded as well as the the fundamentalist view of Scripture. In spite of the reality of paradigmshifts, the raports of deputies and the decisions of assemblies does not reflect this reality. Chapter 5 tries to point a way out to handle the differences in the ligt of the Reformed view of Scripture. Focus is placed on the place the sociohistorical context holds in the revelationhistorical exegetical process. The chapter further investigates the relation between desicions on Scriptural grounds and the right to protest according to artical 31 of the Reformed Chrurchorder. Attention in given to so called ordinary cases ans essential cases. The notion that differences can be solved when dessicions is based on Scripture alone is put forward in this chapter. / Thesis (M.Th. (Church and Dogma History))--North-West University, Potchefstroom Campus, 2011
29

Sola scriptura : die Skrifbeskouing in die Gereformeerde Kerke van Suid-Afrika sedert 1959 : ʼn dogmaties-historiese ondersoek / Christiaan Jooste

Jooste, Christiaan January 2011 (has links)
In the history of the Reformed Churches of South Africa (RCSA) great emphisis was placed on the notion to make decisions on the basis, and in accordance to the Scriptures. In spite of this notion, the church community of the RCSA stand in the midst of great tension regarding some decisions. In the fifty year period from the centenary festival in 1959 to the 150 year festival in 2009, assemblies of the church community were confronted with many objections to decisions regarding racial relations, the acceptance of the 1983-translation of the Bible in Afrikaans, the acceptance of the 2001-Psalter, the use of small cups in the Holy Communion and the role of women in the offices of deacon, elder and minister. The question that’s being addressed in this study is, if a shift in the RCSA’s view of Scripture took place. Chapter 2 gives an historical overview of the decisions that gave way to to the differences mentioned above. From the historical overview the aspects regarding the view of Scripture can be formulated. In chapter 3 the relation between the differences and the view of Scripture are examined. At first a short definition of the reformed view of Scripture are formulated. Hermeneutical and view of Scripture aspects of the raports of deputies and decisions of assemblies are tested according to the formulated definition of a reformed view of Scripture. Chapter 4 examines the influence that paradigm shifts had on the differences in the RCSA. Focus is placed on the influence of postmodernism on the one hand and fundamentalism on the other. Attention is also given to the stance of the RCSA on these two paradigms of thought with relation to the view of Scripture. In light of the reformed view of Scripture the postmodern approach to hermeneutics is discarded as well as the the fundamentalist view of Scripture. In spite of the reality of paradigmshifts, the raports of deputies and the decisions of assemblies does not reflect this reality. Chapter 5 tries to point a way out to handle the differences in the ligt of the Reformed view of Scripture. Focus is placed on the place the sociohistorical context holds in the revelationhistorical exegetical process. The chapter further investigates the relation between desicions on Scriptural grounds and the right to protest according to artical 31 of the Reformed Chrurchorder. Attention in given to so called ordinary cases ans essential cases. The notion that differences can be solved when dessicions is based on Scripture alone is put forward in this chapter. / Thesis (M.Th. (Church and Dogma History))--North-West University, Potchefstroom Campus, 2011
30

Significance, the vessel and the domestic

Brown, Sandra Lois, School of Design, UNSW January 2004 (has links)
Throughout history, people have made or acquired vessels from which to sip their favourite beverage. In the contemporary domestic setting, households frequently accumulate multiples of the same type of object in numbers that are considerably greater than is necessary and practical for use alone. Of these many objects there are often individual pieces that have special significance for the owner or user. Some are so valued that they may even be removed and set aside because of their perceived importance. The research was initiated by a previous study of tea drinking vessels coupled with a desire, as an object maker and collector, to find out why people have special items that they designate as personally important. The aim was to identify how significance could be recognised in specific objects and whether the notion that a group of features used to gauge such objects could be conveyed into studio based work. The research outcomes are evidenced in a text-based document (which articulates the theoretical and empirical elements of the enquiry) and a body of creative studio work developed in response to aspects of the investigation. The document encompasses two components of the study. The first references material from the fields of museum and cultural studies, pivotal in focusing the enquiry. This contributed to the compilation of a general and speculative inventory of qualities that might pertain to objects deemed ???significant???. During these early investigations it became evident that a more in depth and contemporary analysis of significant drinking vessels, their owners and/or users was required. A Survey Questionnaire regarding personal use and special drinking vessels preceded a series of Interviews with a selected group of Australia curators, artists, academics and collectors who discussed and analysed their association with a personally significant drinking vessel. Subsequently, the content of these interviews became central to the focus of the research and outcomes. The research isolates a number of attributes that are commonly identified in objects that, whatever their condition, are deemed ???significant???. These describe the maker, usage, ownership, association and historical context. The perceived value or worth of the object for its owner, is recognised as a consequence of significance and declares the object as distinctive. This outcome is clearly validated by the interviews. The studio work develops from the fusion of personal narrative that has been enhanced by findings of the research. In particular, it references the cherished object, most especially those pieces that have been retained despite the ravages of time and use. The resulting work was exhibited as Trace Elements ??? Marking Time: Significance, the Vessel and the Domestic at Kudos Gallery, Paddington in April 2004.

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