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Dissertations / Theses on the topic 'Cycling'
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Intravaia, Paul Joseph. "Cycling." OpenSIUC, 2014. https://opensiuc.lib.siu.edu/theses/1509.
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Merger, Alexis Nicole. "Life Cycling: Cardiovascular Benefits of Cycling for Women." Thesis, The University of Arizona, 2015. http://hdl.handle.net/10150/579421.
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Cardiovascular disease is the leading killer of both men and women in the United States. Though prevalent in both genders, certain risk factors leave women especially susceptible to cardiovascular disease. Aerobic exercise has been shown to both prevent and control major risk factors. Through public awareness and outreach, women within the community will have the opportunity to learn about their risks and begin steps towards a healthier lifestyle. This paper will inform the average reader about the anatomy and physiology of the cardiovascular system, the risk factors associated with cardiovascular disease, and the history and heart-health benefits of cycling all while taking special consideration to note female-specific factors. Its purpose is to encourage women to evaluate their lifestyle, understand their cardiovascular risk factors, and begin cycling and eating well in order to live a healthier, longer life.
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Silva, Alexandre Manuel Oliveira da. "Cycling cities." Master's thesis, Universidade de Lisboa, Faculdade de Arquitetura, 2019. http://hdl.handle.net/10400.5/19235.
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Dissertação de Mestrado Integrado em Arquitetura, com a especialização em Urbanismo apresentada na Faculdade de Arquitetura da Universidade de Lisboa para obtenção do grau de Mestre.A presente investigação centra-se na temática de promoção da mobilidade ciclável e a devida integração com os transportes ferroviários, tendo em consideração a orografia do terreno. Num momento em que a procura por soluções sustentáveis no âmbito da mobilidade em cidade tem vindo a crescer, constata-se que a mobilidade com recurso à bicicleta nas deslocações diárias poderá atenuar as dificuldades existentes, podendo esta ser considerada como um dos modos de transporte mais eficazes nas deslocações urbanas. Numa fase inicial, a revisão dos conceitos aborda as questões relacionadas com esta temática, onde as posições de diversos autores fundamentam a importância que a mobilidade ciclável desempenha nas mais diversas áreas, desde da gestão e planeamento territorial às vertentes sociais, económicas, ambientais e culturais. Numa segunda fase, desenvolve-se um estudo sobre a aptidão ciclável no município de Vila Franca de Xira, procurando estudar a possibilidade de integrar a bicicleta enquanto modo de transporte diário de ligação às estações ferroviárias da Linha da Azambuja. Este estudo procura responder às adversidades encontradas aquando do processo de planeamento de redes cicláveis e tenta acomodar a questão orográfica, através do estudo prévio dos declives do terreno. O objetivo passa por entender de que forma é possível atenuar esta condicionante e, assim, promover junto da comunidade local o uso da bicicleta nas suas deslocações diárias de e para as diversas estações ferroviárias do concelho.
ABSTRACT: The present research focuses on the theme of promoting cycling mobility, currently conditioned by terrain orography and its effective integration with rail transport. At a time when the search for sustainable solutions in city mobility has been growing, it is clear that cycling mobility in daily commutes may alleviate existing difficulties and may be considered as one of the most effective urban modes of transport At an initial phase, the review of the concepts addresses issues related to this theme, where the positions of several authors justify the importance of cycling mobility in a broad variety of areas, ranging from territorial management and planning to social, economic, environmental and cultural aspects. At a second phase, a study is developed focusing on the cycling ability in the municipality of Vila Franca de Xira, seeking to study the possibility of integrate the bicycle as a daily mode of transport in the connections to Linha da Azambuja railway statios. This study seeks to respond to the the adversities encountered during the planning process of cycling networks and to accommodating the orographic question, through a preliminary study of the terrains slopes. The objective is to understand how the condition of the slopes may be mitigated and, thus, to promote bicycle use in the daily commute to and from the various railway stations in the municipality.
N/A
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Roop, Adrian Heston. "THE ANTHROPOLOGY OF CYCLING: AN ETHNOGRAPHIC DETAIL OF CYCLING'S EXPERIENCE." OpenSIUC, 2010. https://opensiuc.lib.siu.edu/theses/319.
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Competitive cycling is a sport that is popular around the world. My thesis explores the relationship between cyclesport and society. I begin my thesis with an introduction to the topic of cycling and how I will elucidate cycling's relationship within the sense of how cycle racing engages the nexus between the environment and subject in and through language use, embodiment, and practice. I then explain the methods that I use. Phenomenology, lived experience research, embodied performance, and language use. I utilized my experiences in different cycling communities and interviews to gain access to how cycling comes to be practiced in the daily lives of its participants. Many of the findings reflect the dynamics of gender, language use, discipline, and balance.
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Reilly, Lyle. "City centered cycling." AUT University, 2009. http://hdl.handle.net/10292/895.
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This project explores design considerations and processes involved in the development of sports performance clothing specifically aimed at city cycling commuters. Research with a focus on smart clothing and electronic integration was used to form a technical framework in which the requirements of the end user were addressed. The result being the creation of a wearable electronic jacket containing a lighting system aimed at improving safety and comfort aspects affecting cycle commuters. The project methodology was essentially practice based with a strong experimental approach linked to the physical testing and refinement of electronic and clothing integration. Design aesthetics were equally important and are presented as a visual record linked to the use of computer related technologies which have influenced the design planning and processes of the project.
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Springer, Alexander D. "Optimizing cycling power." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/105573.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (page 29).
In this study we determine a viable bioenergetic model for power allocation during a cycling race. Various models have been proposed to address power allocation in races with two models rising above others: the Morton-Margaria Three Tank model and the Skiba Energy Balance model. The energy balance model was implemented in MATLAB and compared against the gold standard implementation in Golden Cheetah to model the depletion of an athlete's energy over the course a ride. The implementation of the model was successful as verified by ride data from a cyclist in the 2014 Tour de France. Additionally, the model was further tested with sample power profiles in order to understand the depletion of energy over the course of a ride. Two key findings emerged from the investigation. First, we require a better account of exhaustion in the energy balance model which can be achieved by weighting the time spent below critical power over the time spent above critical power. This is because a cyclist becomes more exhausted by efforts at higher power outputs compared to the recovery at an effort below critical power. Second, energy balance models should use a variable time constant as rides and races have highly variable recovery periods below critical power which affects the ability of an athlete to reconstitute their energy. Use of a variable time constant could address the weighting of efforts below critical power identified in the first finding as well.
by Alexander D. Springer.
S.B.
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Kaewpanukrangsi, Nuanphan. "Creative-Up-Cycling." Thesis, Malmö högskola, Fakulteten för kultur och samhälle (KS), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-21543.
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The project elaborates design opportunities for a future practice that could promotealternative sustainable lifestyles on waste handling through up-cycling activities. It doesthis on a small scale through engagement in the local communities of the Hildaneighborhood and Segepark students’ accommodations in Sweden. To thesecommunities, creative-up-cycling is explored which it introduced here as an approachwhere neighbors can participate in making new things from leftover materials. Throughthis work creative-up-cycling is a proposed recommendation for a possible service systemon how to share the leftover materials in the local resident’s communities, as well as, howto remake the items no longer needed.The empirical studies explore maker culture lifestyles and include how to find leftovermaterials, tools, space, and skills in order to guide people in creative-up-cyclingalternatives. These creative activities also build social relationship via the integration ofmultidisciplinary citizens who are living in the same community and explorations weredone on how could we elicit the skill sets from those people? What is a useful skill set inthis area today? Values like mutual physical experience, reciprocity, and ownership couldalso be found along the empirical workshops in this project. Additionally, this reportshows some interesting findings pointing towards the design process and the suggestionsof design elements; ‘Co-storage’, ‘Mix and Match furniture shop’, and ‘Renovation andup-cycling’ concept elements.Participatory design (designing with people) has been the core approach in this project.Additionally, I have been influenced by user-centered design, as well as service designapproaches in order to comprehend the services, system and activities of recycling andup-cycling in cities like: SYSAV, STPLN, Cykelköket, Återskapa, Toolpool. The findingpresented here are examples of practices that could make up the composition of recyclingand up-cycling activities in future local communities.
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Underwood, Lindsey. "Aerodynamics of Track Cycling." Thesis, University of Canterbury. Mechanical Engineering, 2012. http://hdl.handle.net/10092/7804.
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The aim of this thesis was to identify ways in which the velocity of a track cyclist could be increased, primarily through the reduction of aerodynamic drag, and to determine which factors had the most significant impact on athlete performance. An appropriate test method was set up in the wind tunnel at the University of Canterbury to measure the aerodynamic drag of different cycling positions and equipment, including helmets, skinsuits, frames and wheels, in order to measure the impact of specific changes on athlete performance.
A mathematical model of the Individual Pursuit (IP) event was also created to calculate the velocity profile and finishing time for athletes competing under different race conditions. The model was created in Microsoft Excel and used first principles to analyse the forces acting on a cyclist, which lead to the development of equations for power supply and demand. The mathematical model was validated using SRM data for eleven, elite track cyclists, and was found to be accurate to 0.31s (0.16%). An analysis of changes made to the bike, athlete, and environmental conditions using the mathematical model showed that the drag area and air density had the greatest impact on the finishing time. The model was then used to predict the finishing times for different pacing strategies by generating different power profiles for a given athlete with a fixed stock of energy (the work done remained the same for all generated power profiles) in order to identify the optimal pacing strategy for the IP. The length of time spent in the initial acceleration phase was found to have a significant impact on the results, although all strategies simulated with an initial acceleration phase resulted in a faster finishing time than all other strategies simulated.
Results from the wind tunnel tests showed that, in general, changes made to the position of the cyclist had the greatest impact on the aerodynamic drag compared to changes made to the equipment. Multiple changes in position had a greater impact on drag than individual changes in position, but the changes were not additive; the total gain or loss in drag for multiple changes in position was not the sum of individual gains or losses in drag. Actual gains and losses also varied significantly between athletes, primarily due to differences in body size and shape, riding experience, and reference position from which changes were made from. Changes in position that resulted in a reduction of the frontal area, such as lowering the handlebars and head, were the most successful at reducing the aerodynamic drag, and a change in skinsuit was found to have the greatest impact on drag out of all equipment changes, primarily due to the choice of material and seam placement. The mathematical model was used to quantify the impact of changes in position and equipment made in the wind tunnel on the overall finishing time for a given athlete competing in an IP event. Time savings of up to 8 seconds were seen for multiple changes in position, and up to 5 seconds for changes to the equipment.
Overall this thesis highlights the significance of aerodynamics on athlete performance in track cycling, suggesting that it is worthwhile spending time and money on research and technology to find new ways to reduce the aerodynamic drag and maximise the speed of cyclists. Although this thesis primarily concentrates on the Individual Pursuit event in track cycling, the same principles can be applied to other cycling disciplines, as well as to other sports.
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Stone, Michael H., Margaret E. Stone, and William A. Sands. "Cycling Your Periodization Plan." Digital Commons @ East Tennessee State University, 2008. https://dc.etsu.edu/etsu-works/4674.
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Smith, Jimmy C. "The Effect of Seat Back Angle on Responses During Recumbent Cycling." Thesis, University of North Texas, 1990. https://digital.library.unt.edu/ark:/67531/metadc332582/.
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The purpose of this study was to evaluate metabolic, cardiorespiratory, and perceptual responses during recumbent cycle ergometry performed at various seat back angles and different work rates. Healthy college-aged men performed steady-state exercise at two work rates, 100 watts (n=46) and 150 watts (n=26), using five back seat angles, 90, 105, 120, 135, and 150 degrees. The results of this study suggest that recumbent seat back angles of 135 to 150 degrees are associated with lower metabolic and cardiorespiratory stress during rest and submaximal exercise than more upright positions. The reduced stress at these angles is accompanied by lower perceptions of exertion and improved seating comfort. The failure of the base-line correction for resting V0 2 to remove the effect of seat back angle implies that the reduced physiological stress associated with these positions is due to reasons other than attenuated resting metabolic costs. It is concluded that the selection of recumbent seat back angles between 135 and 150 degrees can result in improved efficiency, reduced physiological stress, diminished perceptions of exertion, and increased seating comfort.
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Harper, Sara Anne. "The influence of lateral foot displacement on cycling efficiency and maximal cycling power." Kent State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=kent1394551229.
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Klippel, Nathan John. "The effects of hip angle manipulation on submaximal oxygen consumption in collegiate cyclists." Thesis, Montana State University, 2004. http://etd.lib.montana.edu/etd/2004/klippel/KlippelN1204.pdf.
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Frankowski, Hyuma, Kate McKeown, and Joel Mulligan. "Building an International Cycling Community." Thesis, Blekinge Tekniska Högskola, Avdelningen för maskinteknik, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-4120.
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With the increasing population and development of cities, addressing urban transportation is predicted to become a greater challenge. Cycling presents the opportunity to address urban mobility demands without the same degree of environmental, economic and social costs associated with conventional motorized transportation. The intent of this paper is to identify the commonalities and differences between cycling organisations, and what some examples of actions that take advantage of opportunities between these organisations could be. Backcasting from scientifically derived sustainability principles within the Framework for Strategic Sustainable Development was used to validate our research topic. Qualitative research proceeded in four phases. Methods included: literature reviews, field visit, interviews, five-level and SWOT analyses, brainstorming and prioritisation. Research found communication and knowledge transfer within and between cycling organisations could be improved, but doing so requires leadership and resources that are usually lacking. Research also found that there is a desire to present cycling in an inspiring way, but there is a lack of expertise in doing so despite the current unprecedented increase in interest, initiatives and resource allocation related to cycling. As cycling gains more support, it will likely encourage a progressive shift throughout the entire transportation sector toward more sustainable development. This ultimately can play a significant role in moving toward a sustainable society.Please contact the authors by email.
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Ngai, Zoology. "Trophic effects on nutrient cycling." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/2851.
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The top-down effects of consumers and bottom-up effects of resource availability are
important in determining community structure and ecological processes. I experimentally
examined the roles of consumers — both detritivores and predators — and habitat context in
affecting nutrient cycling using the detritus-based insect community in bromeliad leaf wells. I
also investigated the role of multiple resources in limiting plant productivity using meta analyses.
The insect community in bromeliads only increased nitrogen release from leaf detritus in
the presence of a predator trophic level. When only detritivores were present, the flow of stable
isotope-labeled nitrogen from detritus to bromeliads was statistically indistinguishable from that
in bromeliads lacking insects. I suggest that emergence of adult detritivores constitutes a loss of
nitrogen from bromeliad ecosystems, and that predation reduces the rate of this nutrient loss.
Hence, insects facilitate nutrient uptake by the plant, but only if both predators and detritivores
are present. Moreover, predators can affect nutrient cycling by influencing the spatial scale of
prey turnover. This mechanism results in a pattern opposite to that predicted by classic trophic
cascade theory.
Increasing habitat complexity can have implications for nutrient cycling by decreasing
the foraging efficiency of both predators and their prey, and by affecting the vulnerability of
predators to intraguild predation. Along a natural gradient in bromeliad size, I found that,
depending on the relationship between community composition and habitat size, habitat
complexity interacts with the changing biotic community to either complement or counteract the
impact of predators on nutrient uptake by bromeliads.
In contrast to the existing emphasis on single-resource limitation of primary productivity,
meta-analyses of a database of 653 studies revealed widespread limitation by multiple resources,
and frequent interaction between these resources in restricting plant growth. A framework for
analyzing fertilization studies is outlined, with explicit consideration of the possible role of
multiple resources. I also review a range of mechanisms responsible for the various forms of
resource limitation that are observed in fertilization experiments.
These studies emphasize that a wider range of predator and nutrient impacts should be
considered, beyond the paradigm of single resource limitation or classic trophic cascades.
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Feng, Huan, and 冯欢. "The water delivery cycling way." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hub.hku.hk/bib/B50703171.
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Prastka, Katherine. "Phosphorus cycling in intertidal sediments." Thesis, University of East Anglia, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320776.
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Montelius, Malin. "Chlorine Cycling in Terrestrial Environments." Doctoral thesis, Linköpings universitet, Tema Miljöförändring, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-125913.
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Chlorinated organic compounds (Clorg) are produced naturally in soil. Formation and degradation of Clorg affect the chlorine (Cl) cycling in terrestrial environments and chlorine can be retained or released from soil. Cl is known to have the same behaviour as radioactive chlorine-36 (36Cl), a long-lived radioisotope with a half-life of 300,000 years. 36Cl attracts interest because of its presence in radioactive waste, making 36Cl a potential risk for humans and animals due to possible biological uptake. This thesis studies the distribution and cycling of chloride (Cl–) and Clorg in terrestrial environments by using laboratory controlled soil incubation studies and a forest field study. The results show higher amounts of Cl– and Clorg and higher chlorination rates in coniferous forest soils than in pasture and agricultural soils. Tree species is the most important factor regulating Cl– and Clorg levels, whereas geographical location, atmospheric deposition, and soil type are less important. The root zone was the most active site of the chlorination process. Moreover, this thesis confirms that bulk Clorg dechlorination rates are similar to, or higher than, chlorination rates and that there are at least two major Clorg pools, one being dechlorinated quickly and one remarkably slower. While chlorination rates were negatively influenced by nitrogen additions, dechlorination rates, seem unaffected by nitrogen. The results implicate that Cl cycling is highly active in soils and Cl– and Clorg levels result from a dynamic equilibrium between chlorination and dechlorination. Influence of tree species and the rapid and slow cycling of some Cl pools, are critical to consider in studies of Cl in terrestrial environments. This information can be used to better understand Cl in risk-assessment modelling including inorganic and organic 36Cl.Klorerade organiska föreningar (Clorg) bildas naturligt i mark och påverkar klorets kretslopp genom att de stannar kvar längre i marken. Detta stabila klor anses ha samma egenskaper som klor-36, som är en långlivad radioisotop med en halveringstid på 300 000 år. Klor-36 förekommer i olika typer av radioaktivt avfall och om klor-36 sprids i naturen finns det en potentiell risk för människor och djur genom biologiskt upptag. Syftet i denna avhandling är att öka kunskapen om fördelningen och cirkulationen av klorid (Cl-) och Clorg i terrestra miljöer med hjälp av studier i laboratoriemiljö samt en fältstudie i skogsmiljö. Resultaten visar att bildningshastigheten av Clorg är högst i barrskogsjord och rotzonen tycks vara en aktiv plats. Det finns också en större mängd Cl- och Clorg i barrskogsjordar än i betesmark och jordbruksmark. Den mest betydande faktorn som styr halterna av Cl- och Clorg är trädsort, medan geografiskt läge, atmosfäriskt nedfall, och jordmån är av mindre betydelse. Bildning och nedbrytning av Clorg sker med liknande hastigheter, men det tycks finnas två förråd av Clorg i jorden varav ett bryts ner snabbt och ett mer långsamt. Bildningshastigheten av Clorg är lägre i jordar med höga halter av kväve medan nedbrytningshastigheterna inte påverkas av kväve. Slutsatsen från studiernas resultat är att klor i hög grad är aktivt i mark och att Cl- och Clorg halterna bestäms av en dynamisk jämvikt mellan bildning och nedbrytning av Clorg. I studier av klor i terrestra miljöer bör trädsorters inverkan och nedbrytning av olika klorförråd beaktas då det kan ge varierande uppehållstider av Cl- och Clorg i mark. Denna information är viktig vid riskbedömningar av hur radioaktivt klor kan spridas och cirkulera vid en eventuell kärnkraftsolycka.
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V, Gesamtverband der Deutschen Versicherungswirtschaft e. "Pedelec - Naturalistic Cycling Study: Forschungsbericht." Gesamtverband der Deutschen Versicherungswirtschaft e. V, 2014. https://publish.fid-move.qucosa.de/id/qucosa%3A74668.
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Elektrofahrräder, sogenannte Pedelecs, erfreuen sich seit einigen Jahren zunehmender Beliebtheit. Ihre Zahl wird in Deutschland auch in den nächsten Jahren kontinuierlich steigen. Mit wachsender Verbreitung dieser neuen Form von Mobilität ergeben sich eine Reihe neuer Herausforderungen für den Straßenverkehr. So stellt sich die Frage, wie sich potentiell höhere Geschwindigkeiten, die mit Pedelecs erreicht werden können, auf die Verkehrssicherheit auswirken. Weiterhin ist offen, ob ältere Personen als aktuelle Hauptnutzergruppe des Verkehrsmittels einem gesteigerten Sicherheitsrisiko bei der Pedelec-Nutzung unterliegen. Auch mögliche Veränderungen des Mobilitätsverhaltens sind nicht auszuschließen. Im Rahmen dieses Projektes wurden Aspekte des Mobilitäts- und Sicherheitsverhaltens von Zweiradfahrern in einer sogenannten „Naturalistic Cycling Study“ untersucht. Bei diesem methodischen Ansatz werden die Zweiräder von Versuchsteilnehmern mit Kameras und zusätzlicher Sensorik ausgestattet, um das „normale“ Fahr- und Nutzungsverhalten der jeweiligen Fahrer über einen längeren Zeitraum hinweg dokumentieren zu können. Insgesamt wurden 90 Teilnehmer akquiriert. Neunundvierzig davon waren Nutzer eines sogenannten Pedelec25. Derartige Elektrofahrräder unterstützen beim Treten bis 25 km/h und sind klassischen Fahrrädern rechtlich gleichgestellt. Weitere 10 Teilnehmer nutzten ein sogenanntes Pedelec45, welches entsprechend bis 45 km/h unterstützt, und unter anderem mit Helm- und Kennzeichenpflicht verbunden ist. Als Kontrollgruppe nahmen zudem 31 Radfahrer an der Untersuchung teil. Um der aktuellen Nutzerstruktur Rechnung zu tragen, wurden die Teilnehmer zusätzlich auch nach Alter ausgewählt. Jeweils etwa ein Drittel der Teilnehmer waren 40 Jahre alt oder jünger, zwischen 40 und 65 Jahre alt, oder 65 Jahre und älter. Jeder der 90 Teilnehmer wurde mit Hilfe der Instrumentierung über einen Zeitraum von insgesamt 4 Wochen auf seinen Wegen mit seinem Zweirad beobachtet. Zudem führten Teilnehmer für eine dieser Wochen ein sogenanntes Aktivitätentagebuch, das dazu diente, jegliche Wege und deren Zwecke zu erfassen. Zusätzlich füllten sie vor Beginn und nach Ablauf der Datenerhebung eine Reihe von Fragebögen aus, die sich mit dem Nutzungsverhalten, der Unfallhistorie und weiteren Fragestellungen befassten. Insgesamt wurden mehr als 4.000 Fahrten mit einer Gesamtlänge von knapp 17.000 km aufgezeichnet. Um mögliche sicherheitsrelevante Verkehrssituationen aufzufinden erfolgte eine umfangreiche Videokodierung. Zu diesem Zweck wurde jede einzelne Fahrt vollständig gesichtet, und potentiell gefährliche Verkehrssituationen nach einem zuvor definierten Schema identifiziert und kodiert. Zusätzlich wurden mit Hilfe von Radsensordaten Weglängen, Wegdauern und vor allem Geschwindigkeiten analysiert. Die Ergebnisse der Untersuchung zeigen, dass die Nutzung von Elektrofahrrädern nicht mit einer erhöhten Auftretenswahrscheinlichkeit von kritischen Situationen einhergeht. Auch mit Blick auf das Alter der Teilnehmer zeigen sich diesbezüglich keine Unterschiede. Generell interessant ist eine differenzierte Betrachtung der Situation mit Blick auf die jeweiligen Konfliktpartner. So kam es gehäuft zu Konfliktsituationen mit (hoch)motorisierten Fahrzeugen (Pkw, Lkw). Allerdings war auch eine substantielle Zahl an problematischen Interaktionen mit Fußgängern zu beobachten. Bei der Auswertung der Fahrdaten ergaben sich die zu erwartenden Unterschiede in den Durchschnittsgeschwindigkeiten der jeweiligen Zweiräder. So fuhren Pedelec25-Nutzer im Schnitt geringfügig (ca. 2 km/h), Pedelec45-Nutzer jedoch deutlich (ca. 8 km/h) schneller als Radfahrer. Auch ergaben sich im Hinblick auf die Geschwindigkeit deutliche Altersunterschiede, unabhängig vom Zweiradtyp. Im Mobilitätsverhalten hingegen ließen sich keine auffälligen Effekte durch die Nutzung von Elektrofahrrädern feststellen.
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Ryan, Edward J. "CAFFEINE TIMING AND CYCLING PERFORMANCE." Kent State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=kent1309615310.
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Shannon, Samuel Tomas. "Relational Ethics and Relationship Cycling." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1483649086650909.
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Naukkarinen, Vesa. "Factors related to cycling performance." Thesis, University of North Texas, 2001. http://www.oregonpdf.org.
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Thesis (M.S.)--University of North Texas, 2001.Includes bibliographical references (leaves 44-46). Also available online (PDF file) by a subscription to the set or by purchasing the individual file.
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Fiolo, Nicholas J., Christopher B. Taber, Caleb D. Bazyler, Cody T. Haun, Robert Duncan, Aaron M. Thomas, Michael W. Ramsey, and Michael H. Stone. "Utilizing Weightlifting for Cycling Performance." Digital Commons @ East Tennessee State University, 2014. https://dc.etsu.edu/etsu-works/3844.
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Curry, Daniel T. "Lower limb muscle function during cycling." Thesis, University of Ottawa (Canada), 1990. http://hdl.handle.net/10393/5853.
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The purpose of this study was to describe the functional role of the lower limb musculature during stationary cycling using electromyography, muscle-tendon unit length changes, and segmental kinematics. Five subjects were filmed (100 Hz) in synchrony with the collection of LE EMG activity of the gluteus maximus, semitendinosus, semimembranosus, rectus femoris, vastus lateralis, soleus, gastrocnemius, and tibialis anterior muscles during stationary cycling at 160 W (90 r/min). The results showed that extension during the propulsive phase of the pedal cycle was the result of high concentric activity of both the monoarticular and biarticular muscles. Furthermore, these muscles functioned according to their expected anatomical roles (Rasch and Burke, 1978). This investigation, therefore, finds little evidence for the existence of paradoxical muscle function as hypothesized by Lombard (1903), Molbech (1965), or Rasch & Burke (1978).
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Dubois, Kristal D. "Carbon cycling in northern temperate lakes." Thesis, University of Ottawa (Canada), 2006. http://hdl.handle.net/10393/29347.
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We present two novel stable isotope methods for measuring lake metabolism and compare the results to traditional techniques. The delta 18O method measures planktonic gross primary production (GPP) from dissolved oxygen concentrations, isotopes and respiration (R) and the delta 13C method measures "whole-lake" GPP and R from dissolved oxygen and carbon concentrations and isotopes. All three methods showed GPP was greater than R over the ice-free season and estimates of GPP were not significantly different. There was also no significant difference in R as measured by bottle incubations and the delta13C method. However, the delta 13C method does not account for inputs of external carbon which will result in underestimation of R and overestimation of GPP. In systems with significant allochthonous carbon inputs, the delta13C method cannot be accurate unless these inputs are accounted for.
The delta18O method was used to measure metabolic parameters of twenty-one northern temperate lakes and showed GPP dominated over R during the ice-free season. GPP and R were most strongly correlated with lake temperature, which in turn is a function of the amount of solar radiation received by the lake. Our results imply that it is this solar radiation that drives planktonic gross primary productivity, which in turn drives the majority of planktonic respiration. Variation in dissolved organic carbon only explained 8% of the variation in planktonic R, while variation in planktonic GPP explained approximately 80% of the variation in planktonic R.
Despite general autotrophy in the lakes, they were generally oversaturated in CO2 during the ice-free season, on average 252+/-25%. However, we found little evidence to conclude that this was the result of an excess of in situ respiration over production. The magnitude of the annual excess of R over GPP was not sufficient to account for the flux to the atmosphere. Moreover, carbon evasion was not a function of respiratory flux, nor did the isotopic signature of dissolved CO2 in the lakes present evidence of respiration. Groundwater inputs of carbon dioxide represent a plausible source for carbon dioxide oversaturation in some but not all of the lakes sampled.
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Xu, Zhihong, and n/a. "Nitrogen Cycling in Leucaena Alley Cropping." Griffith University. Division of Australian Environmental Studies, 1991. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20050906.155955.
Full textAbstract:
Field experiments were conducted on an Alfisol in the semi-arid tropics of northern Australia to investigate nitrogen (N) cycling in the leucaena (Leucaena leucocephala) alley cropping system. This is a farming system in which maize (Zea mays L.) is grown in alleys formed by leucaena hedgerows spaced 4.5 metres apart. Mineralization of N from Ieucaena (prunings) and maize residues was studied under field conditions. Response of maize growth to addition of N fertilizer and plant residues was evaluated both in field plot and microplot experiments. The fate of fertilizer N and leucaena N was examined over four consecutive seasons. The decomposition (loss of mass) of dry, cut 15N-labelled leucaena residues differed from that of intact fresh leucaena prunings in the first cropping season although no difference was detected after one year. At the end of one cropping season, 3 months after application, 58-72% of 15N-labelled leucaena had decomposed compared to only 34-36% of fresh leucaena prunings. Similar trends occurred at 20 and 52 days after application. The extent of decomposition of fresh leucaena prunings (28-33%) was similar at two loading rates (2.4 and 4.7 t DM ha -1) by 3 months after addition. About 72% of young 15N labelled maize residues was decomposed by 3 months after addition in the presence of fresh leucaena prunings. Decomposition of 15N-labelled leucaena residues and unlabelled fresh prunings was 91% and 88% respectively 14 months after addition. After 2 years the corresponding values were 96% and 94%. When N content of the recovered residues was taken into account, the values were 95% and 94% after 14 months, and the same (97%) after 2 years. Maize yield and N uptake were significantly increased following addition of either unlabelled fresh leucaena residues or 15N-labelled thy Ieucaena residues. Application of N ferilizer produced a thither increase in the presence of the residues. The maize yield and N uptake with the 15N-labelled leucaena were not different from those with the unlabelled residues. There was a significant positive interaction between N fertilizer and leucaena prunings which increased maize production. Addition of maize residues decreased the yield and N uptake of maize compared with that obtained in the presence of N fertilizer at 40 kg N ha~1 and leucaena residues (2.4 t DM ha-1). There was a marked residual benefit of N fertilizer applied in the first season at 36 kgN hat in the presence of leucaena prunings on the second maize crop yield and N uptake, but not on the third crop. However, a significant residual benefit of leucaena prunings added in the first season was found in DM yield and N uptake of the second and third maize crop. The short-term fate of 15N applied in plant residues was examined during two separate cropping seasons. By 20 days after application of separate 15N-labelled leucaena leaves, stems and petioles, 3-9% of the added 15N could be found in maize plants, 33-49% was in surface residues, 36-48% in the 2 m soil proffle and 0.3-22% unaccounted for. In a separate experiment when leucaena components were not separated, 5% of 15N applied in leucaena residues was taken up by maize 52 days after addition, 45% was in residues, 25% was in soil and 25% was unaccounted for. Jn another experiment, maize recovered 6% of added leucaena 15N after 2 months, 39% remained in residues, 28% was in soil and 27% was not recovered. Incorporation of 15N-labelled leucaena residues in the soil did not increase recoveiy of leucaena 15N by maize compared with placement of the residues on the soil surface. By the end of one cropping season (3 months after application), 9% of added 15N was recovered by maize from 15N-labelled leucaena. There was a similar 15N recoveiy from 15N-labelled maize residues applied as mulch at 1.7 t DM ha1 together with unlabelled leucaena prunings at 2.4 t DM ha ~. In both cases, 30-32% of added 15N was detected in soil, 28% in residues, and 31-34% apparently lost. The short-term fate of fertilizer 15N was different from that of 15N added in plant residues. In a 52-day experiment, maize recovered 65-79% of fertilizer 15N applied at low rates (6.1 and 12.2 kg N ha -1) in the presence of leucaena prunings, 21-34% was present in soil, and less than 1% was not recovered. By 2 months after application, recoveiy of fertilizer 15N by maize was 41% from N fertilizer added at 80 kg N ha -1, 35% from N fertilizer at 40 kg N ha -1 in the presence of leucaena prunings, and 24% from N fertilizer at 40 kg N ha -1 in the presence of maize residues and leucaena prunings. The corresponding deficits (unaccounted-for 15N) were 37%, 38% and 47% respectively. A small but significant amount of the fertilizer 15N was present in the unlabelled leucaena residues (3%) and in the mixture of unlabelled leucaena and maize residues (7%) present on the soil surface. However, application of the plant residues did not affect recoveiy of the fertilizer 15N in soil (21-24%). When N fertilizer was applied at 40 kg N hi1 in the presence of leucaena prunings, 43% of fertilizer 15N was recovered by maize at the end of cropping season, 20% in soil, 2% in residues, and 35% unaccounted for. The long-term fate of fertilizer 15N was compared with that of leucaena 15N in an experiment over four cropping seasons. In the first season, maize tops recovered 50% of the fertilizer 15N but only 4% of the leucaena 15N. In the second, third and fourth seasons, maize (tops + roots) recovered 0.7%, 0.4% and 0.3% of the initial fertilizer 15N compared with 2.6%, 1.8% and 1.4% of the initial leucaena 15N. In the second, third and fourth seasons, recovery of the initial fertilizer 15N (12-14%) in soil was much lower than that of the initial leucaena 15N (38-40%). There was no further loss of the fertilizer 15N after the first season. However, the cumulative 15N deficit for the leucaena 1N in the first two seasons was 50%--thissuggested an additional loss of 23% since the end of the first season. There was no further loss of 15N from either residual fertilizer 15N or residual leucaena 15N in the third and fourth seasons. In conclusion, application of leucaena prunings could substantially increase maize yield and N uptake although some supplementary N fertilizer may be required to achieve maximum crop yield. Maize recovered only a small amount of added leucaena N in the first year. Most of the leucaena residue N was present in the soil and remaining residues after one season. This residue N would be gradually available for plant uptake by subsequent crops. Of course, annual additions of leucaena prunings would appreciably increase the pool of available N over time. Thus, application of leucaena prunings could substantially improve soil fertility in the long term.
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Jenkins, Meaghan Edith Biological Earth & Environmental Sciences Faculty of Science UNSW. "Carbon cycling in sub-alpine ecosystems." Awarded by:University of New South Wales. Biological, Earth & Environmental Sciences, 2009. http://handle.unsw.edu.au/1959.4/44822.
Full textAbstract:
The relationship between temperature and soil respiration has been well explored although uncertainties remain. This thesis examined the relationship between temperature and rates of heterotrophic respiration in soils from three adjacent sub-alpine Australian vegetation types; woodland, shrubland and grassland. Temperature sensitivity of soil (Q10) has recently been a hotly debate topic, one side concluding that decomposition of recalcitrant, less labile components of soil organic matter are insensitive to temperature. Whilst others argue that there is no difference in the temperature sensitivities of labile and recalcitrant carbon pools. Robust modeling of rates of soil respiration requires characterization of the temperature response of both labile and recalcitrant pools. Laboratory incubation provides a means of characterizing the temperature response of rates of respiration whilst reducing the confounding effects encountered in the field, such as seasonal fluctuations in temperature, moisture and substrate supply. I used a novel system that allowed laboratory measurement of gas exchange in soils over a range of temperatures under controlled conditions. Measurements included CO2 efflux and O2 uptake over a range of temperatures from 5 to 40oC, characterization of temperature response and sensitivity, and respiratory quotients. Rates of heterotrophic respiration fitted both exponential and Arrhenius functions and temperature sensitivity varied and depended on the model used, vegetation type and depth in the soil profile. Long-term incubation indicated both labile and resistant pools of carbon had similar temperature sensitivities. Respiratory quotients provided a strongly predictive measure of the potential rate of decomposition of soil C, independent of the temperature response of respiration, providing a tool that may be used alongside derived parameters to help understand shifts in microbial use of C substrates. Vegetation type influenced soil chemical properties and rates of heterotrophic respiration. Rates of respiration correlated well with concentrations of carbon and nitrogen as has been previously observed, unlike previous studies however a positive correlation was observed between indices of plant available phosphorus and respiration. The soils examined were from three adjacent vegetation types formed on common geology, I concluded that vegetation type had a significant influence on soil, in contrast to the commonly held view by ecologists that soil type drives patterns in vegetation. Climatic effects such as longer, dryer hotter summer, reduced snow cover and increased incidence of extreme weather events such as frosts and bushfire are likely to drive patterns in vegetation in this region and therefore have a significant impact on carbon cycling in Sub-alpine Australian soils.
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Thompson, Melissa Anne. "Mechanical power output in sprint cycling." Connect to online resource, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1446102.
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Scrase, Franklin McCleary. "Enhanced phosphate cycling using Tithonia diversifolia." Thesis, Bangor University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.409570.
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Hopker, James G. "An Investigation of efficiency within Cycling." Thesis, University of Kent, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.504668.
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So, Shuk-yee Joan, and 蘇淑儀. "Cycling development in Hong Kong context." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B30253123.
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Al-Attas, Rana. "Evaluating Player Experience in Cycling Exergames." Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/26215.
Full textAbstract:
Obesity has become a worldwide problem that most countries are trying to fight. It affects many people, irrespective of age, race, gender, or religion; anyone can suffer from obesity, which leads to serious problems, both for individuals and for society as a whole. In this study we have selected two groups of people: the basic people who do not exercise on a weekly basis, and the average people who exercise regularly, every week. We have explored the attitude of the two groups in regards to mixing exercises with games, in order to motivate the people with basic activity levels to exercise more frequently. We have used a qualitative standard online questionnaire from AttrakDiff, which evaluates user experience through four important aspects: a) quality; b) subjective understanding of quality and subjective evaluation of quality; c) pragmatic and hedonic features; and d) emotional and behavioural effects. We also did a qualitative study and a quantitative study of some of the important factors present during exercise. The results of the qualitative and quantitative studies were very encouraging as they revealed that mixing games with exercise can transform boring exercises into entertaining ones. It can also motivate players to continue and repeat the exercises. The ANOVA test was applied and it shows that combining games with a stationary bike has a significant effect on the speed and the average rotation per minute of the participants.
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Ochana, Andrew. "Power cycling of flip chip assemblies." Thesis, Loughborough University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.418328.
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Xiong, Yijun. "Phosphorus cycling under different redox conditions." Thesis, University of Leeds, 2018. http://etheses.whiterose.ac.uk/22045/.
Full textAbstract:
Phosphorus is a basic but essential nutrient element for life, as a major limiting nutrient, is also important for controlling primary productivity on geological timescales. However, P cycling is highly redox dependent through Earth history. The fate of P cycling in many environments is still not clear. This thesis is to investigate mineralogical controls on P cycling under different redox conditions. New geochemical data is reported in the low sulfate, euxinic Lake Cadagno, Switzerland, to investigate the behaviour of the phosphorus cycle. Sulfide-driven release of phosphorus from organic matter and Fe (oxyhydr)oxide minerals is re-trapped by Fe(II) phosphate to constrain the extent of P recycling, and this process is highly sulfate dependent. New experiments are designed to investigate what minerals control P cycling in the water column under different conditions. With the increase of P, Green rust is transformed to vivianite which shows that P concentrations exert first order controls on the mineralogy of Fe minerals, with strong implications for the availability of dissolved P in the water column. In order to quantify the extent of P cycling versus fixation in the sediments under different redox conditions, mass balance models are made based on 4 key redox scenarios. Analogous to those which were prevalent at various intervals in Earth history, under ancient episodes of ferruginous conditions, low flux of recycled P back to water column is controlled by both P re-uptake by Fe(III) (oxyhydr)oxide and the formation of Fe(II) phosphate. During the mid-Proterozoic and during Phanerozoic, under low sulfate euxinia, the flux of recycled P is constrained by Fe(II) phosphate formation. This study provides supporting evidence to the suggestion that the positive primary productivity feedback is constrained by these processes.
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Pine, Kerrin J. "Localized fast field-cycling NMR relaxometry." Thesis, University of Aberdeen, 2014. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=215228.
Full textAbstract:
Conventional MRI relies on a strong fixed magnetic field B0 which is stable during the imaging process. By contrast, field-cycling MRI switches the strength of B0 up or down during an experiment. In this way, field-cycling provides access to endogenous information not accessible to standard MRI, such as enhanced T1 relaxation at certain NMR frequencies due to interactions between hydrogen and nitrogen nuclei in proteins. However, biomedical research of T1 dispersion is limited by the unavailability of equipment and rapid software methods. Strategies are presented to address these deficiencies. A removable electromagnet was designed and implemented for use with a 59-mT vertical-field, permanent-magnet based imager. The resistive magnet locally offsets the primary field over a small projected region to enable field-cycling relaxometry on an otherwise-conventional imager. Radiofrequency coils were constructed to suit the electromagnet’s configuration. T1 dispersion measurements were demonstrated for, separately, the finger joints and forearm of a human volunteer. Prior to this work, producing graphs of T1 dispersion from a volume of interest required lengthy T1 mapping at each field strength step. A new pulse sequence combining SR/IR T1 determination with field-cycling and point-resolved spectroscopy localization enables the measurement of dispersion curves of a volume selected from a pilot image. Its advantages include less partial voluming than whole-sample relaxometry, as well as better SNR and faster acquisition times than image-based techniques. The sequence’s sensitivity is sufficient to reveal distinctive ‘quadrupole dips’ in dispersion curves. To the author’s knowledge, it is the first pulse sequence to enable the relationship between T1 and field strength to be examined in times which are feasible for clinical investigations. Used together as presented in this thesis, the hardware and software developed represent a step towards field-cycling being used to reveal useful diagnostic information inaccessible to conventional MRI.
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Xu, Zhihong. "Nitrogen Cycling in Leucaena Alley Cropping." Thesis, Griffith University, 1991. http://hdl.handle.net/10072/365424.
Full textAbstract:
Field experiments were conducted on an Alfisol in the semi-arid tropics of northern Australia to investigate nitrogen (N) cycling in the leucaena (Leucaena leucocephala) alley cropping system. This is a farming system in which maize (Zea mays L.) is grown in alleys formed by leucaena hedgerows spaced 4.5 metres apart. Mineralization of N from Ieucaena (prunings) and maize residues was studied under field conditions. Response of maize growth to addition of N fertilizer and plant residues was evaluated both in field plot and microplot experiments. The fate of fertilizer N and leucaena N was examined over four consecutive seasons. The decomposition (loss of mass) of dry, cut 15N-labelled leucaena residues differed from that of intact fresh leucaena prunings in the first cropping season although no difference was detected after one year. At the end of one cropping season, 3 months after application, 58-72% of 15N-labelled leucaena had decomposed compared to only 34-36% of fresh leucaena prunings. Similar trends occurred at 20 and 52 days after application. The extent of decomposition of fresh leucaena prunings (28-33%) was similar at two loading rates (2.4 and 4.7 t DM ha -1) by 3 months after addition. About 72% of young 15N labled maize residues was decomposed by 3 months after addition in the presence of fresh leucaena prunings. Decomposition of 15N-labelled leucaena residues and unlabelled fresh prunings was 91% and 88% respectively 14 months after addition. After 2 years the corresponding values were 96% and 94%. When N content of the recovered residues was taken into account, the values were 95% and 94% after 14 months, and the same (97%) after 2 years. Maize yield and N uptake were significantly increased following addition of either unlabelled fresh leucaena residues or 15N-labelled thy Ieucaena residues. Application of N ferilizer produced a thither increase in the presence of the residues. The maize yield and N uptake with the 15N-labelled leucaena were not different from those with the unlabelled residues. There was a significant positive interaction between N fertilizer and leucaena prunings which increased maize production. Addition of maize residues decreased the yield and N uptake of maize compared with that obtained in the presence of N fertilizer at 40 kg N ha~1 and leucaena residues (2.4 t DM ha-1). There was a marked residual benefit of N fertilizer applied in the first season at 36 kgN hat in the presence of leucaena prunings on the second maize crop yield and N uptake, but not on the third crop. However, a significant residual benefit of leucaena prunings added in the first season was found in DM yield and N uptake of the second and third maize crop. The short-term fate of 15N applied in plant residues was examined during two separate cropping seasons. By 20 days after application of separate 15N-labelled leucaena leaves, stems and petioles, 3-9% of the added 15N could be found in maize plants, 33-49% was in surface residues, 36-48% in the 2 m soil proffle and 0.3-22% unaccounted for. In a separate experiment when leucaena components were not separated, 5% of 15N applied in leucaena residues was taken up by maize 52 days after addition, 45% was in residues, 25% was in soil and 25% was unaccounted for. Jn another experiment, maize recovered 6% of added leucaena 15N after 2 months, 39% remained in residues, 28% was in soil and 27% was not recovered. Incorporation of 15N-labelled leucaena residues in the soil did not increase recoveiy of leucaena 15N by maize compared with placement of the residues on the soil surface. By the end of one cropping season (3 months after application), 9% of added 15N was recovered by maize from 15N-labelled leucaena. There was a similar 15N recoveiy from 15N-labelled maize residues applied as mulch at 1.7 t DM ha1 together with unlabelled leucaena prunings at 2.4 t DM ha ~. In both cases, 30-32% of added 15N was detected in soil, 28% in residues, and 31-34% apparently lost. The short-term fate of fertilizer 15N was different from that of 15N added in plant residues. In a 52-day experiment, maize recovered 65-79% of fertilizer 15N applied at low rates (6.1 and 12.2 kg N ha -1) in the presence of leucaena prunings, 21-34% was present in soil, and less than 1% was not recovered. By 2 months after application, recoveiy of fertilizer 15N by maize was 41% from N fertilizer added at 80 kg N ha -1, 35% from N fertilizer at 40 kg N ha -1 in the presence of leucaena prunings, and 24% from N fertilizer at 40 kg N ha -1 in the presence of maize residues and leucaena prunings. The corresponding deficits (unaccounted-for 15N) were 37%, 38% and 47% respectively. A small but significant amount of the fertilizer 15N was present in the unlabelled leucaena residues (3%) and in the mixture of unlabelled leucaena and maize residues (7%) present on the soil surface. However, application of the plant residues did not affect recoveiy of the fertilizer 15N in soil (21-24%). When N fertilizer was applied at 40 kg N hi1 in the presence of leucaena prunings, 43% of fertilizer 15N was recovered by maize at the end of cropping season, 20% in soil, 2% in residues, and 35% unaccounted for. The long-term fate of fertilizer 15N was compared with that of leucaena 15N in an experiment over four cropping seasons. In the first season, maize tops recovered 50% of the fertilizer 15N but only 4% of the leucaena 15N. In the second, third and fourth seasons, maize (tops + roots) recovered 0.7%, 0.4% and 0.3% of the initial fertilizer 15N compared with 2.6%, 1.8% and 1.4% of the initial leucaena 15N. In the second, third and fourth seasons, recovery of the initial fertilizer 15N (12-14%) in soil was much lower than that of the initial leucaena 15N (38-40%). There was no further loss of the fertilizer 15N after the first season. However, the cumulative 15N deficit for the leucaena 1N in the first two seasons was 50%--thissuggested an additional loss of 23% since the end of the first season. There was no further loss of 15N from either residual fertilizer 15N or residual leucaena 15N in the third and fourth seasons. In conclusion, application of leucaena prunings could substantially increase maize yield and N uptake although some supplementary N fertilizer may be required to achieve maximum crop yield. Maize recovered only a small amount of added leucaena N in the first year. Most of the leucaena residue N was present in the soil and remaining residues after one season. This residue N would be gradually available for plant uptake by subsequent crops. Of course, annual additions of leucaena prunings would appreciably increase the pool of available N over time. Thus, application of leucaena prunings could substantially improve soil fertility in the long term.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Division of Australian Environmental Studies
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Masters-Waage, Nicholas. "Redox cycling under nuclear legacy conditions." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/redox-cycling-under-nuclear-legacy-conditions(abb173ad-0a8c-47b9-a2e7-99ea2048d2c2).html.
Full textAbstract:
Subsurface contamination is common at nuclear sites and it is likely that radioactive wastes will be managed in the long-term via burial in a deep Geological Disposal Facility (GDF). The migration of radionuclides in the geosphere from such sites is a major societal concern. In particular, long-lived, redox-active radionuclides (in the case of this thesis: 99Tc and Np) can migrate over large distances due to their high solubility under oxic conditions. Bioremediation has been proposed as a mechanism to limit the migration of 99Tc and Np in the environment. Here, an electron donor is supplied to the subsurface and soluble Tc(VII) and Np(V) are reduced to poorly soluble Tc(IV) and Np(IV), respectively. Reduction occurs via direct microbial action (termed bioreduction) or through radionuclide reaction with the by-products of microbial metabolism (primarily Fe(II)). Given the ubiquity of microorganisms and Fe in the geosphere, similar reactions can be expected in the deep subsurface surrounding a GDF. Once reduced, the long-term stability of the Tc(IV) and Np(IV) phases will significantly impact migration rates. Oxidative dissolution of Tc(IV)- and Np(IV)-bearing solids has been demonstrated in the literature and can be pervasive, thus questioning the efficacy of bioreduction. However, these studies have been conducted over short time-scales and during a single period of oxidation. Given the long half-life of 99Tc and Np and the ephemeral nature of redox conditions in the subsurface, there is a need to better understand 99Tc and Np biogeochemistry during longer time-scales and across multiple redox cycles. In this thesis, microcosm experiments have been used to address this knowledge gap. Sediment and groundwater used in the microcosms were representative of the Sellafield Ltd. nuclear site. For Tc, three successive redox cycles (reduction followed by oxidation with O2) over 2 years, gradually reduced the extent of Tc remobilisation during oxidation, and molecular scale characterisation of solids revealed that sediment associated Tc was always present as Tc(IV). Further, over time sequential extractions and EXAFS revealed an increased significance of Tc-Fe bonding in the sediment at the expense of TcO2. Despite this, a small but significant fraction of Tc(IV) was also found to be stable in solution during the experiments and XAS and TEM analysis suggested this was Tc(IV) associated with magnetite colloids. In other experiments completed with higher concentrations of bioavailable Fe (added as ferrihydrite to sediments, and in pure culture experiments with Geobacter sulfurreducens), the significance of Tc-Fe bonding was again highlighted, and potential Tc(IV) incorporation into biogenic magnetite was also documented. In experiments with Np, virtually all of the Np(V) added to oxic groundwater was removed to the sediment commensurate with microbially mediated Fe(III) reduction. Further, in systems with elevated bioavailable Fe, Np removal from solution was more extensive. Taken together, the data for Tc and Np reveals critical links between redox-active radionuclides and Fe cycling in sediments over periods of years and across multiple redox cycles. Furthermore, these processes help to predict the long-term fate of radioactive contamination at the Sellafield Ltd. nuclear site and have implications for contaminated land worldwide.
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Moore, Nathan F. "Slow-Cycling Cancer Cells: A Dissertation." eScholarship@UMMS, 2012. https://escholarship.umassmed.edu/gsbs_diss/620.
Full textAbstract:
Tumor recurrence after chemotherapy is a major cause of patient morbidity and mortality. Recurrences are thought to be due to small subsets of stem-like cancer cells that are able to survive chemotherapy and drive tumor re-growth. A more complete understanding of stem-like cancer cell regulation is required to develop therapies to better target and eliminate these cells.
Slow-cycling stem cells are integral components of adult epithelial tissues and may give rise to cancer stem cell populations that share similar characteristics. These slow-cycling adult stem cells are inherently resistant to traditional forms of chemotherapy and transference of this characteristic may help to explain therapy resistance in cancer stem cell populations. Using a novel application for the proliferation marker CFSE, we have identified populations of slow-cycling cancer cells with tumor initiating capabilities. As predicted, slow-cycling cancer cells exhibit a multi-fold increase in chemotherapy resistance and retain the ability to re-enter the cell cycle. Furthermore, we observed consistent over-expression of the CDK5 activator, p35, in slow-cycling cancer cells. Manipulation of p35 expression in cancer cells affects cell cycle distribution and survival when these cells are treated with traditional forms of chemotherapy. Additionally, we demonstrate that alterations in p35 expression affect BCL2 levels, suggesting a mechanism for the survival phenotype.
Combined, our data suggest a model whereby slow-cycling stem-like cancer cells utilize the p35/CDK5 complex to slow cell cycling speed and promote resistance to chemotherapy. Future p35 targeting, in combination with traditional forms of chemotherapy, may help eliminate these cells and reduce tumor recurrence rates, increasing long-term patient survival.
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Baker, Simon Charles. "The biogeochemical cycling of sulphur compounds." Thesis, University of Warwick, 1992. http://wrap.warwick.ac.uk/110339/.
Full textAbstract:
The concept of a particular atom, compound or group of compounds being transformed by geochemical, anthropogenic and biological processes on a global scale is not new: the cycling of water and carbon and nitrogen have been recognised in biology and geography. A similar cycle can be constructed for sulphur, which at the most basic level is much like that of carbon. The primary difference is that unlike carbon dioxide (C02) and photosynthesis, biological agents do not play as great a part in the removal of sulphur compounds from the atmosphere to a terrestrial form.
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Ramsey, Michael W. "Physiology of Sprint and Road Cycling." Digital Commons @ East Tennessee State University, 2011. https://dc.etsu.edu/etsu-works/4106.
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Menaspa, Paolo. "Analysis of road sprint cycling performance." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2015. https://ro.ecu.edu.au/theses/1575.
Full textAbstract:
Sprint cycling ability is a key determinant of road cycling performance, with many races designed specifically for sprinters. The ability to excel in the final sprint is relevant for both individual riders and teams. Despite the importance of sprints within professional road cycling, the characteristics of professional road sprints and sprinters have yet to be extensively described. Thus, the overall objective of the five research studies contained within this doctoral thesis was to describe road cycling sprint performance and improve the general understanding of the physical, technical and tactical factors associated with such performances.
The first two descriptive field studies document the physical and physiological demand of sprint races during actual road cycling competitions. Specifically, Study 1 was designed to quantify the demands of sprinting in the male professional category. Seventeen competitions from six male professional cyclists (mean ± SD: age, 27.0 ± 3.8 y; height, 1.76 ± 0.03 m; weight, 71.7 ± 1.1 kg) who placed Top 5 in professional road races were analysed. Calibrated SRM power meters were used to monitor power output, cadence and heart rate. Data were averaged over the entire race, different durations prior to the sprint (60, 10, 5 and 1 min) and during the actual sprint. Variations in power during the final 10 min of the race were quantified using Exposure Variation Analysis. Power, cadence and heart rate were different between various phases of the race, increasing from 316 ± 43 W, 95 ± 4 rpm and 88 ± 3 % of maximal heart rate in the last 10 min to 487 ± 58 W, 102 ± 6 rpm and 96 ± 2 % of maximal heart rate in the last minute prior to the sprint. The peak power during the sprint was 17.4 ± 1.7 W∙kg-1. Exposure Variation Analysis revealed a significantly greater number of short duration and high intensity efforts in the final five minutes of the race, compared with the penultimate five minutes (p=0.01). These findings quantified the power output requirements associated with high level sprinting in men’s professional road cycling and highlighted the need for both aerobic and anaerobic fitness. In Study 2, the characteristics of successful road sprints in professional and under 23 y male cycling races were compared. As in Study 1, Study 2 also described the exercise intensity for the sprinters throughout final 10 min of the race. Nine successful (Top 3) sprints performed by a professional (PRO: 23 y, 1.76 m, 71.8 kg) and an under 23 (U23: 18 y, 1.67 m, 63.2 kg) cyclist sprinter were analysed in this study. No statisticaldifferences were found between PRO and U23 in the absolute peak power, mean power, duration and total work during the sprint (PRO: 1370 ± 51 W, 1120 ± 33 W, 14.5 ± 2.4 s, 16.2 ± 2.6 KJ; U23: 1318 ± 60 W, 1112 ± 68 W, 12.8 ± 1.1 s, 14.2 ± 1.4 KJ). However, the intensity of the race recorded in the last 10 min prior to the sprint was significantly higher in PRO compared with U23 (4.6 ± 0.3 and 3.7 ± 0.2 W·kg-1, respectively). Race duration, total elevation gain (TEG) and mean power were similar between PRO and U23. In conclusion, the physiological demands leading into road sprints (intensity of the last 10 min) were found to be higher in PRO compared to U23 races. Nevertheless, a similar sprint power output (> 2500 W·Ap-1 or > 15.5 W·kg-1 for approximately 14 s, with a peak power output > 3100 W·Ap-1 or > 19 W·kg-1; where Ap is Projected Frontal Area) indicates that sprint characteristics may be similar in PRO and U23.
As a result of the findings observed in the first two studies of this thesis, Study 3 was designed to better understand the effects of variable and non-variable exercises that replicate the intensity of the final portion of road competitions on maximal sprint performance. In this laboratory trial, ten internationally competitive male cyclists (age, 20.1 ± 1.3 y; height, 1.81 ± 0.07 m weight, 69.5 ± 4.9 kg; and VO2max, 72.5 ± 4.4 ml·kg-1·min-1) performed a 12-s maximal sprint in a rested state and again following: i) 10 min of non-variable cycling, and ii) 10 min of variable cycling. Variable and non-variable trials were conducted in a randomized, crossover fashion. The intensity during the 10 min efforts gradually increased to replicate the pacing observed in final sections of cycling road races. During the variable cycling subjects performed short (2 s) accelerations at 80% of their peak sprint power, every 30 s. Mean power output, cadence and heart rate during the 10 min efforts were similar between conditions (5.3 ± 0.2 W∙kg-1, 102 ± 1 rpm, and 93 ± 3 %, respectively). Post exercise blood lactate concentration and perceived exertion immediately after exercise were also similar (8.3 ± 1.6 mmol∙L-1, 15.4 ± 1.3 (6-20 scale), respectively). Peak and mean power output and cadence during the subsequent maximal sprint were not significantly different between the three experimental conditions (p≥0.14). These results indicate that neither the variable nor the non-variable 10 min efforts performed within this study impaired the sprint performance in elite competitive cyclists.
Due to the importance of the elevation gain variable in road cycling, the fourth study of this thesis was methodological and investigated the consistency of commercially available devices used to measure the TEG during races and training. This chapter was separated in two observational validation studies. Garmin (Forerunner 310XT, Edge 500 Edge 750 and Edge 800; with and without elevation correction) and SRM (Power Control 7) devices were used to measure TEG over a 15.7 km mountain climb performed on 6 separate occasions (6 devices; Study 4a) and during a 138 km cycling event (164 devices; Study 4b). TEG was significantly different between Garmin and SRM devices (p
The final study of this thesis was an analysis of technical and tactical factors that influence sprint performance in professional competitions; particular focus was put on the TEG which was a factor identified as a potential cause of fatigue. More specifically, the subject of Study 5 was the highest international ranked professional male road sprint cyclist during the 2008-2011 seasons. Grand Tour sprint stages were classified as WON, LOST, or DROPPED from the front bunch prior to the sprint. Video of 31 stages were analysed for mean speed of the last km, sprint duration, position in the bunch and number of teammates at 60, 30, and 15 s remaining. Race distance, TEG and mean speed of 45 stages were determined. Head-to-head performances against the 2nd to 5th most successful professional sprint cyclists were also reviewed. Within the 52 Grand Tour sprint stages the subject started, he WON 30 (58%), LOST 15 (29%), was DROPPED in 6 (12%) and had one crash. Position in the bunch was closer to the front and the number of team members was significantly higher in WON compared to LOST at 60, 30 and 15 s remaining (p
In conclusion, the general findings of this thesis were as follows: as expected, exercise intensity significantly increases in the last 10 min of relatively flat road races; there is a significantly greater number of short duration and high intensity efforts in the final 5 min of competitive road cycling races when compared with the penultimate 5 min; sprint duration and peak power output does not differ between PRO and U23 races and is approximately 13 s and 17 W∙kg-1, respectively; the physiological demands in the 10 min before the sprint are higher in PRO compared to U23 races; neither a variable nor a non-variable 10 min lead up effort appears to impair the sprint performance of elite competitive cyclists; measurements of elevation gain are consistent within devices of the same brand, but differed between brands or when different settings were used; and technical and tactical aspects of road sprinting are related to performance outcomes.
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Nimmerichter, Alfred. "Mechanical power output during cycling : the efficacy of mobile power meters for monitoring exercise intensity during cycling." Thesis, University of Exeter, 2011. http://hdl.handle.net/10036/3146.
Full textAbstract:
One of the most meaningful technical innovations in cycling over the past two decades was the development of mobile power meters. With the ability to measure the physical strain under “real world” outdoor conditions, the knowledge of the demand during cycling has improved enormously. Power output has been described as the most direct measure of intensity during cycling and consequently power meters becomes a popular tool to monitor the training and racing of cyclists. However, only limited research data are available on the utilisation of power meters for performance assessment in the field or the analysis of training data. Therefore, the aims of the thesis were to evaluate the ecological validity of a field test, to provide an extensive insight into the longitudinal training strategies of world-class cyclists and to investigate the effects of interval training in the field at difference cadences. The first study aimed to assess the reproducibility of power output during a 4-min (TT4) and a 20-min (TT20) time-trial and the relationship with performance markers obtained during a laboratory graded exercise test (GXT). Ventilatory and lactate thresholds during a GXT were measured in competitive male cyclists (n = 15; VO2max 67 ± 5 mL . min−1 . kg−1; Pmax 440 ± 38 W ). Two 4- min and 20-min time-trials were performed on flat roads. Strong intraclass-correlations for TT4 (r = 0.98; 95 % CL: 0.92-0.99) and TT20 (r = 0.98; 95 % CL: 0.95-0.99) were observed. TT4 showed a bias ± random error of −0.8 ± 23W or −0.2 ± 5.5%. During TT20 the bias ± random error was −1.8 ± 14 W or 0.6 ± 4.4 %. Both time-trials were strongly correlated with performance measures from the GXT (p < 0.001). Significant differences were observed between power output during TT4 and GXT measures (p < 0.001). No significant differences were found between TT20 and power output at the second lactate-turn-point (LTP 2) (p = 0.98) and respiratory compensation point (RCP) (p = 0.97). In conclusion, TT4 and TT20 mean power outputs are reliable predictors of endurance performance. TT20 was in agreement with power output at RCP and LTP 2. Study two aimed to quantify power output (PO) and heart rate (HR) distributions across a whole season in elite cyclists. Power output and heart rate were monitored for 11 months in ten male (age: 29.1 ± 6.7 y; VO2max: 66.5 ± 7.1 mL . min−1 . kg−1) and one female (age: 23.1y; VO2max: 71.5 mL . min−1 . kg−1) cyclist. In total, 1802 data sets were sampled and divided into workout categories according to training goals. The PO at the RCP was used to determine seven intensity zones (Z1-Z7). PO and HR distributions into Z1-Z7 were calculated for all data and workout categories. The ratio of mean PO to RCP (intensity factor, IF) was assessed for each training session and for each interval during the training sessions (IFINT). Variability of PO was calculated as coefficient of variation (CV ). There was no significant difference in the distribution of PO and HR for the total season (p = 0.15), although significant differences between workout categories were observed (p < 0.001). Compared with PO, HR distributions showed a shift from low to high intensities. IF was significantly different between categories (p < 0.001). The IFINT was related to performance (p < 0.01), although the overall IF for the session was not. Also, total training time was related to performance (p < 0.05). The variability in PO was inversely associated with performance (p < 0.01). In conclusion, HR accurately reflects exercise intensity over a total season or low intensity workouts but is limited when applied to high intensity workouts. Better performance by cyclists was characterised by lower variability in PO, greater training volume and the production of higher exercise intensities during intervals. The third study tested the effects of low-cadence (60 rev . min−1) uphill (Int60) or high-cadence (100 rev . min−1) flat (Int100) interval training on PO during 20 min uphill (TTup) and flat (TTflat) time-trials. Eighteen male cyclists (VO2max: 58.6 ± 5.4 mL . min−1 . kg−1) were randomly assigned to Int60, Int100 or a control group (Con). The interval training comprised of two training sessions per week over four weeks, which consisted of 6 bouts of 5 min at the PO at RCP. For the control group, no interval training was conducted. A two-factor ANOVA revealed significant increases on performance measures obtained from GXT (Pmax: 2.8 ± 3.0 %; p < 0.01; PO and VO2 at RCP: 3.6 ± 6.3 % and 4.7 ± 8.2 %, respectively; p < 0.05; and VO2 at ventilatory threshold: 4.9 ± 5.6 %; p < 0.01), with no significant group effects. Significant interactions between group and the uphill and flat time-trials, pre vs. post-training on time-trial PO were observed (p < 0.05). Int60 increased PO during both, TTup (4.4 ± 5.3 %) and TTflat (1.5 ± 4.5 %), whereas the changes were − 1.3 ± 3.6 %; 2.6 ± 6.0 % for Int100 and 4.0 ± 4.6 %; − 3.5 ± 5.4 % for Con, during TTup and TTflat, respectively. PO was significantly higher during TTup than TTflat (4.4 ± 6.0 %; 6.3 ± 5.6 %; pre and post-training, respectively; p < 0.001). These findings suggest that higher forces during the low-cadence intervals are potentially beneficial to improve performance. In contrast to the GXT, the time-trials are ecologically valid to detect specific performance adaptations.
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Jarrett, Haydn. "An investigation into physiological responses and ratings of perceived exertion to submaximal cycle ergometry when using aerodynamic and drop handlebars /." View online, 1991. http://repository.eiu.edu/theses/docs/32211998880384.pdf.
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McIntyre, Jordan. "The effects of different intermittent priming strategies on 3km cycling performance a thesis submitted to Auckland University of Technology in partial fulfilment of the requirements for the degree of Master of Health Science, 2007." Click here to access this resource online, 2007. http://hdl.handle.net/10292/443.
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Thorp, George. "The Effect of Compression Recovery Pants on Cycling Performance." University of Toledo / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1430470588.
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Abbiss, Chris. "Regulation of exercise intensity in well-trained cyclists." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2008. https://ro.ecu.edu.au/theses/178.
Full textAbstract:
It is known that exercise performance may be improved if athletes select the optimal regulation of pace during exercise. Despite this knowledge, the best possible strategies that may delay the development of fatigue and ensure optimal performance during a variety of exercise tasks are not yet known. Thus, the primary purpose of the six research studies contained within this doctoral thesis was to describe pacing strategies and improve our understanding of factors that influence the regulation of intensity during self-paced exercise.
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Olson, Karl E. "VeloCal a web-based cycling event scheduler /." [Denver, Colo.] : Regis University, 2006. http://165.236.235.140/lib/kolson2006.pdf.
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Kätelhön, Friedrich Enno [Verfasser]. "Electrochemical redox-cycling devices / Friedrich Enno Kätelhön." Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2014. http://d-nb.info/1065970293/34.
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Noffke, Anna [Verfasser]. "Phosphorus cycling in anoxic sediments / Anna Noffke." Kiel : Universitätsbibliothek Kiel, 2014. http://d-nb.info/1063933595/34.
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Sun, Baoguo. "Thermal Cycling of Solid Oxide Fuel Cells." Thesis, Imperial College London, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.486561.
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Solid-oxide fuel cells (SOFCs) are energy conversion devices that theoretically have the capability of producing electrical- energy for as long as the fuel and oxidant are supplied to the electrodes and perfonnance is expected for at least 40,000 hours. However, it is observed that perfonnance degrades under repeated thennal cycling conditions, which limits the practicaI.operating life of these SOFCs. Therefore, the mechanism of damage to planar and integrated planar SOFCs (IPt' SOFCs) on thennal cycling is the subject of this thesis. A detailed literature review has been carried out and a mechanical and thennal properties database of the key materials used in these SOFCs has been built up. Extensive work has been done on the residual ~tress analysis of anode-supported and inert substrate supported SOFCs. Analytical model, surface profile measurement (Talysurf) and XRD stress analysis were used to detennine t4e residual stresses in the components. From this study, it was found that the difference of thennal expansion coefficients between components in the SOFCs is the dominant source of stress during thennal cycling in the absence of significant temperature gradient. For the integrated planar SOFCs, it was found tha~ the cells degraded due to the failure of the sealing materials during cooling. For anode supported planar SOFCs, the electrolyte (YSZ) is under high compressive stress when cooling from sintering or operating temperature to room temperature and the anode is under very small tensile stress. The results from theoretical analysis, XRD stress measurement and literature were compared and found that they agreed with each other quite well.
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Pinchuk, Robert. "Liposan production in the Self-Cycling Fermentor." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0033/MQ64242.pdf.
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