Dissertations / Theses on the topic 'Diaphragm'
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Orrey, Samantha Taylor. "The relationship between diaphragm thickness, diaphragm strength and diaphragm endurance in young, healthy individuals." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/86666.
Full textENGLISH ABSTRACT: Introduction: In the intensive care unit population, approximately 40% of patients require mechanical ventilation and 20-25% of these patients will encounter difficulties in the discontinuation of mechanical ventilation. As mechanical ventilation affects the diaphragm, a better understanding of the structural and functional changes of the diaphragm is warranted. Method: A scoping review was done to determine whether a relationship between diaphragm thickness, diaphragm strength and diaphragm endurance had been established. Seven databases were searched using a specific search strategy. Papers were identified based on pre-defined inclusion criteria. Data was extracted by the primary investigator (PI) into a self-developed excel spreadsheet. Criteria were developed for a more focused review to inform the planning of a primary study. The primary study investigated the relationship between diaphragm thickness, diaphragm strength and diaphragm endurance in young, healthy individuals. A sample of convenience was used; included healthy individuals (18-24); three activity-levels (sedentary; endurance- and strength related sporting activities); stratified for gender and BMI. Measurements included: Sonographic measurement of diaphragm thickness; mouth pressure manometer measurements for diaphragmatic strength; and fatigue resistance index as a measure of endurance. Participants were instructed to breathe through a pressure threshold device at 60% of PImax until task failure. The fatigue resistance index was calculated as PImax final/PImax initial. Intra-rater reliability was established and testing procedures standardised a priori. Results: 405 full texts were retrieved and assessed for inclusion into the review. Papers identified the evaluation of diaphragm function in a variety of populations. 23 papers were included in the focused review. Six papers were published on diaphragm thickness, six on diaphragm strength and eleven on diaphragm endurance. No papers identified the correlation between diaphragm thickness, diaphragm strength and diaphragm endurance. 55 subjects, males and females, were recruited for the primary study. Groups were similar at baseline with regards to gender, age and BMI. The mean age of the sample was 21.16 years (SD = 1.55), with a mean body mass index (BMI) of 25.43 kg/m2 (SD = 3.70). A moderate positive correlation was established between diaphragm thickness and diaphragm strength measurements (r = 0.52; r2 = 0.27; p < 0.01). Diaphragm thickness was not correlated with diaphragm endurance (r = -0.15; r2 = 0.02; p = 0.29). No relationship was found between the strength of the diaphragm and the endurance of the diaphragm (r= -0.19; r2 = 0.04; p= 0.16). Conclusion: Guidelines for the measurement of diaphragm function do exist, but they are not adhered to by the majority of studies. Study procedures are inconsistently reported and this may affect the reproducibility of techniques in future studies. We further conclude that a correlation exists between diaphragm thickness and diaphragm strength. The use of ultrasound to measure diaphragm thickness proved to be a reliable technology and gave a moderate indication of the strength of the diaphragm. This technology may help clinicians to detect and monitor dysfunction of the diaphragm in the early stages of admission to the acute setting.
AFRIKAANSE OPSOMMING: Inleiding: Ongeveer 40% van pasiente wat in intensiewe sorgeenheid behandel word, benodig intubasie en meganiese ventilasie. Tot 25% van hierdie pasiënte sal probleme ondervind in die staking van meganiese ventilasie. Meganiese ventilasie beïnvloed die diafragma, daarom word n beter begrip van die strukturele en funksionele veranderinge van die diafragma benodig. Metode: 'n Literatuur oorsig is gedoen om te bepaal of daar 'n verhouding bestaan tussen die dikte, krag en uithouvermoë van die diafragma. Sewe databasisse is deurgesoek aan die hand van spesifieke databasis gedefinieerde soektog strategie. Relevante artikels is geïdentifiseer aan die hand van pre-gedefinieerde insluiting kriteria. Data is onttrek en in ‘n self-ontwikkelde datablad opgesom deur die primêre ondersoeker (PI). Hierdie inligting is gebruik in die beplanning van ‘n primêre studie. Die doel van die primêre studie was om die verhouding tussen die diafragma dikte, krag en uithouvermoë in jong, gesonde individue te ondersoek. ‘n Gerieflikheids steekproef is gebruik; insluitend gesonde individue (18-24); drie aktiwiteits vlakke (passief; uithouvermoë- en krag verwante sportaktiwiteite) en breë spektrum vir geslag en ligaamsbou (BMI). Metings ingesluit: sonografiese meting van die diafragma se dikte; monddruk manometer metings vir diafragmatiese krag en ‘n moegheid/weerstand indeks as maatstaf van diafragmatiese uithouvermoë. Deelnemers is opdrag gegee om asem te haal deur toestel met druk maksimum gestel 60% van PImax, tot mislukking. Die moegheid/weerstand indeks is bereken as PImax finale / PImax oorspronlik. Intra-meter betroubaarheid is bepaal en toets prosedures is gestandaardiseer voordat data ingesamel is. Resultate: 405 vol teks artikels is uitgelig vir insluiting in die literatuur oorsig. Diafragmatiese funksie is ge-evalueer in 'n verskeidenheid bevolkings. Drie en twintig artikels is in die finale oorsig ingesluit. Ses artikels wat diafragma dikte evalueer, ses wat diafragmatiese krag evalueer en elf wat die diafragma se uithouvermoë evalueer is ingesluit in die oorsig. Geen van die artikels uitgelig het ‘n ooreenkoms tussen diafragma dikte, diafragma krag en diafragma uithouvermoë geïdentifiseer nie. 55 deelnemers is gewerf vir die primêre studie. Groepe was soortgelyk by basislyn met betrekking tot geslag, ouderdom en BMI. Die gemiddelde ouderdom van die toetsgroep was 21.16 jaar (SD=1.55), met 'n gemiddelde BMI van 25.43 kg/m2 (SD = 3.70). ‘n Middelmatige positiewe verhouding is waargeneem tussen diafragma dikte en krag (r = 0.52; r2 = 0.27; p < 0.01). Geen verhouding is gevind tussen diafragma dikte en uithouvermoë nie (r= -0.15; r2 = 0.02; p = 0.29). Daar is ook geen verhouding waargeneem tussen diafragma krag en diafragma uithouvermoë nie. (r= 0.19; r2 = 0.04; p = 0.16). Gevolgtrekking: Daar bestaan wel riglyne vir die meting van die diafragma se funksie, maar in die meerderheid van studies word dit nie nagekom nie. Studie prosedures is nie konsekwent weergegee nie en dit kan die resultate van tegnieke beinvloed in toekomende studies. ‘n Matige sterk verhouding is waargeneem tussen diafragmatiese dikte en krag. Die gebruik van ultraklank om die diafragma se dikte te meet is betroubare tegnologie en kan n redelike aanduiding gee oor die krag van die diafragma. Hierdie tegnologie kan praktisyne help om enige disfunksie van die diafragma te identifiseer en te monitor in die vroeë stadiums van toelating tot die akute omgewing.
Singh, Bhajan. "The function of the human diaphragm as a volume pump and measurement of its efficiency /." Connect to this title, 2003. http://theses.library.uwa.edu.au/adt-WU2004.0029.
Full textO'Brien, Patrick Emmet. "Characterizing the Load-Deformation Behavior of Steel Deck Diaphragms using Past Test Data." Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/78679.
Full textMaster of Science
Bott, James Wescott. "Horizontal Stiffness of Wood Diaphragms." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/32641.
Full textMaster of Science
Zhu, Ercheng. "Exercise-induced diaphragm sarcolemmal injury." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0013/NQ52201.pdf.
Full textSingh, Bhajan. "The function of the human diaphragm as a volume pump and measurement of its efficiency." University of Western Australia. School of Biomedical and Chemical Sciences, 2004. http://theses.library.uwa.edu.au/adt-WU2004.0029.
Full textLeong, Hong Sai. "Prediction of deformation of diaphragm wall." Thesis, University of Macau, 2001. http://umaclib3.umac.mo/record=b1445039.
Full textRadell, Peter J. "Studies of diaphragm fatigue and dysfunction /." Stockholm, 2001. http://diss.kib.ki.se/2001/91-628-4751-1/.
Full textHuang, Xinlei. "Diaphragm stiffness in wood-frame construction." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/43908.
Full textSheffy, Jacob. "Recording of diaphragm activity during anaesthesia." Thesis, Oxford Brookes University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.261673.
Full textCruickshank, Jane Laura. "A vibrating silicon diaphragm micro gyroscope." Thesis, University of Newcastle Upon Tyne, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285737.
Full textOttenheijm, Coen, Leo Heunks, and Richard Dekhuijzen. "Diaphragm adaptations in patients with COPD." BioMed Central, 2008. http://hdl.handle.net/10150/610242.
Full textSullivan, Rory Daniel. "Sound insulation of brick diaphragm walls." Thesis, University of Liverpool, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318231.
Full textKazadi, Dieudonne Matang'a. "Non-Newtonian losses through diaphragm valves." Thesis, Cape Peninsula University of Technology, 2005. http://hdl.handle.net/20.500.11838/904.
Full textThe prediction of head losses in a pipe system is very important because head losses affect the performance of fluid machinery such as pumps. In a pipe system, two kinds of losses are observed: major losses and minor losses. In Newtonian and non-Newtonian flow, major losses are those that are due to friction in straight pipes and minor losses are those that are due to pipe fittings such as contractions, expansions, bends and valves. Minor losses must be accurately predicted in a pipe system because they are not negligible and can sometimes outweigh major losses (Edwards et al., 1985). There is presently little data for the prediction of non-Newtonian head losses in pipe fittings in the literature and little consensus amongst researchers (Pienaar et al., 2004). In the case of diaphragm valves, usually, only one loss coefficient value is given in turbulent flow or in laminar flow with no reference to a specific size of the valve, assuming geometrical similarity that would lead to dynamic similarity. However, no one has done a systematic study of various sizes of diaphragm valves from the same manufacturer to establish if this is true. This could be the main reason for discrepancies found in the literature (Hooper, 1981; Perry & Chilton, 1973; Miller, 1978 and Pienaar et al., 2004). This work addresses this issue. A literature revIew on the flow of Newtonian and non-Newtonian fluids has been presented. The work of Hooper (1981) on diaphragm valves and the works of Edwards et al., (1985), BaneIjee et aI., (1994) and Turian et al., (1997) for non-Newtonian fluids in globe and gate valves were found to be relevant to this work.
Dres, Martin. "Evaluation et impact de la dysfonction diaphragmatique au cours du sevrage de la ventilation mécanique chez le patient adulte de réanimation." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066253/document.
Full textDiaphragm dysfunction and critical illness associated neuropathy and myopathy are frequently suspected to cause weaning failure from mechanical ventilation. Some data suggest that both may be gathered into a same entity with two localisations, respiratory and peripheral. This thesis highlights that diaphragm dysfunction and critical illness neuromyopathy are two distinct diseases that don’t frequently coexist. In addition, diaphragm dysfunction has a more severe impact on weaning outcome and prognosis than critical illness associated neuromyopathy and myopathy. However, the level of diaphragm function required to ensure safe mechanical ventilation discontinuation is lower than the level of diaphragm function defining diaphragm dysfunction. This work also shows that investigating diaphragm function may be simplified by the use of ultrasound and diaphragm electromyogram activity
Evcil, E. Hilal Malas Mehmet Ali. "Fetal dönem boyunca Diaphragma gelişimi /." Isparta : SDÜ Sağlık Bilimleri Enstitüsü, 2005. http://tez.sdu.edu.tr/Tezler/TT00205.pdf.
Full textReid, Wendy Darlene. "Fatigue and rest of the hamster diaphragm." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/29168.
Full textMedicine, Faculty of
Pathology and Laboratory Medicine, Department of
Graduate
Beck, Jennifer. "Measurement of diaphragm myoelectric activity in humans." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0007/NQ44360.pdf.
Full textKoch, Wijnandus Franciscus Robertus Maria. "Early development of the human pelvic diaphragm." Enschede : University of Twente [Host], 2006. http://doc.utwente.nl/57608.
Full textBeck, Jennifer 1968. "Measurement of diaphragm myoelectric activity in humans." Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=34912.
Full textPowrie, W. "The behaviour of diaphragm walls in clay." Thesis, University of Cambridge, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372634.
Full textHerlihy, Michael D. "Precast concrete floor support and diaphragm action." Thesis, University of Canterbury. Engineering, 1999. http://hdl.handle.net/10092/9578.
Full textOmar, Wahid. "Diaphragm action in precast concrete floor construction." Thesis, University of Nottingham, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.254392.
Full textMontague, T. I. "Concrete blockwork diaphragm walls - prestressed and unprestressed." Thesis, University of Manchester, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293672.
Full textMulligan, Mark Thomas. "Protein turnover in the isolated mouse diaphragm." Thesis, University of Liverpool, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328161.
Full textPolkey, Michael Iain. "Diaphragm function in chronic obstructive pulmonary disease." Thesis, King's College London (University of London), 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.286262.
Full textMasuda, Toru. "Behavior of deep excavation with diaphragm wall." Thesis, Massachusetts Institute of Technology, 1993. http://hdl.handle.net/1721.1/12172.
Full textIqbal, Qaiser. "The performance of diaphragm type cellular cofferdams." Thesis, University of Southampton, 2009. https://eprints.soton.ac.uk/73612/.
Full textSamples, Matthew W. "Micro Electrostatic Actuation of a Silicon Diaphragm." DigitalCommons@CalPoly, 2015. https://digitalcommons.calpoly.edu/theses/1432.
Full textDridi, Haikel. "Mécanismes cellulaires précoces impliqués dans la dysfonction diaphragmatique induite par la ventilation mécanique." Thesis, Montpellier, 2016. http://www.theses.fr/2016MONT4005/document.
Full textMechanical ventilation (MV) is the first treatment in intensive care for acute respiratory distress syndrome to maintain adequate tissue oxygenation. However, it induces an impairment of the contractile function of the respiratory muscles, particularly the diaphragm, thereby increasing the patient's dependence on his ventilator. This acquired muscle disease have been termed ventilator induced diaphragmatic dysfunction (VIDD). The aim of this thesis is to propose, from a mouse model of mechanical ventilation, early pathophysiologic mechanisms involved in this dysfunction, to identify new therapeutic targets in preventing VIDD.We observed after 6 hours of mechanical ventilation, a mitochondrial oxidative stress which induces ryanodine receptor (RyR1) oxidation, the main calcium channel involved in the ECC. We also showed the presence after an equivalent time of mechanical ventilation, phosphorylation of RyR1, due to protein kinase activation, secondary to an adrenergic stress. Then, we have demonstrated that these post-translational modifications of RyR1 should be necessarily associated to trigger a functional impairment of RyR1 with calcium leakage from the sarcoplasmic reticulum to the cytosol, due to the loss of connection between RyR1 and the stabilizing protein KBP12. In his thesis, we also showed that these calcium homeostasis disorders, induced by 12 hours of ventilation, secondary activates the dependent proteolysis calcium and atrophy.Thus, these results show the benefit of all therapy stabilizing the connection between the RyR1 channel and the FKBP12 protein to prevent VIDD. Indeed, were observed in mice, that a specific mitochondrial anti-oxidant treatment (SS-31), or a specific beta-blocker treatment of beta2 adrenergic pathway (ICI-118551 ) or a treatment that stabilizes directly FKBP12- binding RyR1 (S107 ) prevent early disorders of calcium homeostasis and secondary appearance of proteolysis and atrophy induced by mechanical ventilation.Finally, in the last part of my work thesis, I suggest that mitochondrial ROS production may be associated with remodeling of the mitochondrial network with a preponderance of mitochondrial fission phenomenon. This remodeling could be seen as an adaptation of the mitochondria due to a sudden mismatch between energy production and consumption. Indeed, we showed that an inhibitor of the mitochondrial fission (P110), which blocks the connection between the DRP1 protein and its receptor in our animal model of mechanical ventilation, could prevent the appearance of VIDD. Thus the continuity of this last work of my thesis is to make the link between mitochondrial fission and oxidative stress underlying the disorders of calcium homeostasis. Indeed, I hope to show that this treatment during mechanical ventilation, may decrease mitochondrial ROS production, oxidation of RyR1 channel and calcium leak through the RyR1. This last work will emphasis any therapeutic which limit mitochondrial fission and its consequences, to prevent VIDD.Keywords: RyR1, mitochondria, contractile dysfunction, VIDD, oxidative stress
Weinberg, Jan. "Studies on ventilatory function in chronic neuromuscular disorders /." Stockholm, 1999. http://diss.kib.ki.se/1999/91-628-3936-5/.
Full textSegura-Castillo, Luis. "Bi-layer diaphragm walls : experimental and numerical analysis." Doctoral thesis, Universitat Politècnica de Catalunya, 2013. http://hdl.handle.net/10803/134771.
Full textUn problema habitual en la construcción de pantallas continuas en terrenos con presencia de agua es la existencia de filtraciones. El objetivo de esta tesis busca resolver este problema mediante el desarrollo de un nuevo tipo de pantalla: la pantalla bi-capa (BL, por sus siglas en inglés). El método para construir estos muros se basa en una solución existente: realizar una segunda capa de hormigón impermeable sobre los muros pantalla. En las pantallas BL, la segunda capa se realiza con hormigón con fibras de acero (SFRC) proyectado sobre las pantallas convencionales (llamadas ML en esta tesis) e incluyendo a su vez una adición impermeabilizante. La idea central es maximizar las funciones de la segunda capa, asignándole un rol estructural, además de la función impermeabilizante. La metodología propuesta se basa en la combinación de trabajos experimentales y herramientas numéricas. Se propone un método de diseño para las pantallas BL basado en modelos estructura-sección desacoplados. Posteriormente se utiliza este método para realizar diferentes comparaciones con pantallas ML y un análisis paramétrico exhaustivo de distintos procesos constructivos involucrados en la construcción de las pantallas BL. La campaña experimental realizada comprende dos niveles: a nivel elemento, se estudió la respuesta estructural de pantallas construidas en un edificio real ubicado en Barcelona; a nivel seccional, se midió el nivel de adherencia entre ambas capas de hormigón mediante testigos extraídos de las pantallas antes mencionadas. El modelo a nivel estructural, basado en elementos finitos, se contrastó con los resultados experimentales obtenidos. El modelo seccional se tomó de la bibliografía estudiada. Con el modelo estructura-sección completo se analizaron las pantallas BL. El estudio muestra que la principal resistencia flexional es aportada por la primera capa (el muro pantalla convencional), siendo secundario el aporte de la capa de SFRC. Para el rango de elementos considerados en esta tesis (35 cm a 60 cm de espesor de primera capa y 10 cm de segunda), el incremento de la resistencia última a flexión cuando se considera el aporte de la capa de SFRC, está entre 8% y 15%. Este incremento permite una reducción en el acero de refuerzo de la primera capa de hasta un 7.0% del total del acero de flexión y, hasta cierto punto, también colabora con una reducción en los desplazamientos (alcanzando reducciones de hasta un 7.3% del desplazamiento máximo). Se observó también que la secuencia de proyección es un factor clave a la hora de aprovechar la colaboración extra aportada por la capa de SFRC. Indicaciones específicas se describen a este respecto. Se obtuvo una buena resistencia de adherencia entre hormigones para los testigos extraídos. La resistencia media medida a cada edad (2, 6, y 35 días) estuvo siempre, para los distintos casos, por encima de 1.0 MPa. Más allá de los ensayos puntuales, se observó un comportamiento monolítico a nivel elemento para las pantallas BL experimentales. Se obtuvo un consumo final de materiales similar entre pantallas BL y la consideración conjunta de una pantalla ML más un sistema impermeabilizante externo. Considerar los costos tecnológicos conlleva un costo constructivo mayor para las pantallas BL. Sin embargo, ésta es aún una opción interesante bajo consideraciones particulares, como limitaciones del espacio subterráneo interior o si se desean evitar costos continuos de mantenimiento. En términos generales, se puede decir que la investigación aquí presentada sienta las bases para el desarrollo de la técnica de muros pantalla bi-capa, la cual es una solución prometedora para el problema de las filtraciones en pantallas. No obstante, son necesarios más estudios para poder usar plenamente este tipo de pantallas de forma habitual, e.g. estudios de sostenibilidad detallados, evaluación del riesgo de desprendimiento de la segunda capa, capacidad impermeable y, sobre todo, más ensayos experimentales a escala real
Ward, Michael Edward. "Mechanical, neural and vascular determinants of diaphragm function." Thesis, McGill University, 1994. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=28549.
Full textThe role of afferent impulses travelling in the phrenic nerve in the control of respiratory muscle activity was investigated by electrical stimulation of its central cut end. Activation of these fibres exerts a non-uniform effect on the activities of the upper airway, rib cage and abdominal muscles and may influence respiratory muscle recruitment.
The roles of blood flow and oxygen delivery in determining diaphragm function was investigated. The rate at which diaphragmatic fatigue develops is diminished at high rates of blood flow and this effect is not related to the associated increase in oxygen delivery. The critical oxygen delivery at which oxygen consumption becomes supply dependent is the same for the resting diaphragm as for the rest of the body tissues. Activation of the diaphragm results in a higher critical oxygen delivery, however, this effect is mitigated by an increase in the critical oxygen extraction ratio.
The role of nitric oxide in regulating diaphragmatic blood flow and oxygen uptake was investigated by infusion of N$ sp{G}$-nitro-L-arginine. This treatment increased diaphragmatic vascular resistance, reduced the duration and magnitude of reactive vasodilation and increased the oxygen consumption and critical extraction ratio in the contracting diaphragm.
Li, Shing Foon. "On the analysis of singly-propped diaphragm walls." Thesis, King's College London (University of London), 1990. https://kclpure.kcl.ac.uk/portal/en/theses/on-the-analysis-of-singlypropped-diaphragm-walls(a2d84f73-2205-49e9-957e-9ee48b6dd46f).html.
Full textKantartzi, Christina. "Ground movements during diaphragm wall installation in clays." Thesis, Queen Mary, University of London, 1993. http://qmro.qmul.ac.uk/xmlui/handle/123456789/1532.
Full textLanglois, Gilles. "Diaphragm forming : innovation and application to ocean engineering." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/37530.
Full textVon, Waldburg Arthur Russell. "Diaphragm control in inflated tool forming of composites." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/31074.
Full textSegura, Castillo Luís Emilio. "Bi-layer diaphragm walls : experimental and numerical analysis." Doctoral thesis, Universitat Politècnica de Catalunya, 2013. http://hdl.handle.net/10803/134771.
Full textLeakage is a widespread problem associated with the construction of diaphragm walls whenever they are erected in water-bearing ground. The aim of the present research is to develop a new type of slurry wall: the bi-layer diaphragm wall (BL), which main objective is to tackle the aforementioned problem. The method to construct it is based on an existing solution: casting a second waterproof concrete layer against the diaphragm walls. In the BL technique, the second layer is made of steel fibre reinforced concrete (SFRC) sprayed over the conventional diaphragm wall (called Mono-Layer diaphragm wall (ML) in this thesis), including a waterproof admixture. The central idea is to maximize the functional attributes of the second layer, allowing it to play a structural role in addition to the waterproofing function.The proposed methodology is based on a combination of experimental works and numerical tools. A design method for the BL walls, which is based on an uncoupled structural-section model, is proposed. The method is later used to carry out different comparisons with ML walls and an exhaustive parametric analysis of the construction processes involved in the walls construction. The experimental campaign comprised test at two levels. At element level, the structural response of walls built in a real building located in Barcelona was studied and, at section level, the bond strength between concretes of cores extracted from the abovementioned walls was measured.The model at structural level, which is based on a finite element model, was contrasted with the results obtained in the experimental walls. The sectional analysis is taken from the specialized literature. With the complete structural-section model, the BL walls are analysed. The study shows that the main flexural resistance is provided by the first layer (the conventional diaphragm wall), providing the SFRC layer a secondary flexural resistance.For the geometrical ranges of the elements considered in the thesis (35 cm to 60 cm width first layer, and 10 cm width second layer) the increase in the cross-section ultimate bending resistance when it is strengthened by the SFRC layer is between 8% and 15%. This increase allows a reduction in the steel reinforcement of the first layer (up to 7.0% of the total flexural reinforcement) and, to some extent, it also collaborates with a displacement reduction (reducing up to 7.3% of the maximum displacements). It was also found that the spraying sequence is a crucial parameter to be able to take advantage of the SFRC collaboration, and specific indications are described.Good concrete to concrete bond strength was obtained for the extracted cores. The average shear strength value measured for each age (2, 6 and 35 days) was always above 1.0 MPa for the different cases. Beyond the local test performed, a monolithic behaviour was observed at element level in the experimental walls.A similar final material consumption was observed between the BL walls and the combined consideration of a ML wall and an external waterproof system. The consideration of the technology cost entails a higher construction cost for the BL technique. However, it is still an interesting option under particular circumstances, like space limitations or if continuous maintenance costs want to be avoided in the future.In general terms it can be said that the research herein presented lay the foundation for the development of the bi-layer diaphragm wall technique, which is a promising solution for the leakage problem of diaphragm walls. Nonetheless, more studies are needed to be able to fully use these types of walls as a standard technique, e.g. a detailed cost study and sustainability analysis, debonding risk, waterproofing capability and above all more full scale experimental cases.
Un problema habitual en la construcción de pantallas continuas en terrenos con presencia de agua es la existencia de filtraciones. El objetivo de esta tesis busca resolver este problema mediante el desarrollo de un nuevo tipo de pantalla: la pantalla bi-capa (BL, por sus siglas en inglés). El método para construir estos muros se basa en una solución existente: realizar una segunda capa de hormigón impermeable sobre los muros pantalla. En las pantallas BL, la segunda capa se realiza con hormigón con fibras de acero (SFRC) proyectado sobre las pantallas convencionales (llamadas ML en esta tesis) e incluyendo a su vez una adición impermeabilizante. La idea central es maximizar las funciones de la segunda capa, asignándole un rol estructural, además de la función impermeabilizante. La metodología propuesta se basa en la combinación de trabajos experimentales y herramientas numéricas. Se propone un método de diseño para las pantallas BL basado en modelos estructura-sección desacoplados. Posteriormente se utiliza este método para realizar diferentes comparaciones con pantallas ML y un análisis paramétrico exhaustivo de distintos procesos constructivos involucrados en la construcción de las pantallas BL. La campaña experimental realizada comprende dos niveles: a nivel elemento, se estudió la respuesta estructural de pantallas construidas en un edificio real ubicado en Barcelona; a nivel seccional, se midió el nivel de adherencia entre ambas capas de hormigón mediante testigos extraídos de las pantallas antes mencionadas. El modelo a nivel estructural, basado en elementos finitos, se contrastó con los resultados experimentales obtenidos. El modelo seccional se tomó de la bibliografía estudiada. Con el modelo estructura-sección completo se analizaron las pantallas BL. El estudio muestra que la principal resistencia flexional es aportada por la primera capa (el muro pantalla convencional), siendo secundario el aporte de la capa de SFRC. Para el rango de elementos considerados en esta tesis (35 cm a 60 cm de espesor de primera capa y 10 cm de segunda), el incremento de la resistencia última a flexión cuando se considera el aporte de la capa de SFRC, está entre 8% y 15%. Este incremento permite una reducción en el acero de refuerzo de la primera capa de hasta un 7.0% del total del acero de flexión y, hasta cierto punto, también colabora con una reducción en los desplazamientos (alcanzando reducciones de hasta un 7.3% del desplazamiento máximo). Se observó también que la secuencia de proyección es un factor clave a la hora de aprovechar la colaboración extra aportada por la capa de SFRC. Indicaciones específicas se describen a este respecto. Se obtuvo una buena resistencia de adherencia entre hormigones para los testigos extraídos. La resistencia media medida a cada edad (2, 6, y 35 días) estuvo siempre, para los distintos casos, por encima de 1.0 MPa. Más allá de los ensayos puntuales, se observó un comportamiento monolítico a nivel elemento para las pantallas BL experimentales. Se obtuvo un consumo final de materiales similar entre pantallas BL y la consideración conjunta de una pantalla ML más un sistema impermeabilizante externo. Considerar los costos tecnológicos conlleva un costo constructivo mayor para las pantallas BL. Sin embargo, ésta es aún una opción interesante bajo consideraciones particulares, como limitaciones del espacio subterráneo interior o si se desean evitar costos continuos de mantenimiento. En términos generales, se puede decir que la investigación aquí presentada sienta las bases para el desarrollo de la técnica de muros pantalla bi-capa, la cual es una solución prometedora para el problema de las filtraciones en pantallas. No obstante, son necesarios más estudios para poder usar plenamente este tipo de pantallas de forma habitual, e.g. estudios de sostenibilidad detallados, evaluación del riesgo de desprendimiento de la segunda capa, capacidad impermeable y, sobre todo, más ensayos experimentales a escala real
Kabwe, Aime Mume. "Non-Newtonian loss coefficients for Saunders diaphragm valves." Thesis, Cape Peninsula University of Technology, 2009. http://hdl.handle.net/20.500.11838/914.
Full textThe prediction of the energy losses when designing pipeline and pumping systems requires accurate loss coefficient data. But the loss coefficient data found in the open literature was not adequate for predicting the loss coefficient for Saunders straight-through diaphragm valves. As more accurate loss coefficient data to enable more efficient pipeline designs are scarce in the open literature, it is problematic to predict the head loss due to the pipeline fittings, and particularly for diaphragm valves. Most of the data given in the literature are for turbulent flow based on water. Due to water shortages mining operations are forced to increase their solids concentrations and to operate in laminar flow (Slatter, 2002). Consequently there is a need to determine loss coefficient data in laminar flow for valves used in these industries to ensure energy efficient designs (Pienaar et al., 2001; 2004) or if needed, to derive a new correlation to predict losses through Saunders diaphragm valves. However, a systematic study of various sizes of diaphragm valves of different manufacturers to ascertain, if the same loss coefficient can be applied, has never been done. Therefore a comparison will be made between the data produced in this work and the existing correlations. The objective of this research was to determine loss coefficient data in laminar, transitional and turbulent flow for the Saunders type straight-through diaphragm valves ranging from 40 mm to 100 mm in the fully open, 75 %, 50 % and 25 % open positions, using a range of Newtonian and non-Newtonian fluids. The test work was conducted on the valve test rig in the Flow Process Research Centre at the Cape Peninsula University of Technology. This work investigated only Newtonian and time independent homogeneous non-Newtonian fluids or slurries flowing through Saunders straight-through diaphragm valves in the turbulent, transitional and laminar regimes. Weir-type Saunders valves and time-dependent fluid behaviour were not investigated in this study. Preamble Non-Newtonian Loss Coefficients for Saunders Diaphragm Valves A Mume Kabwe The results for each test are presented in the form of valve loss coefficient (kvalve) against Reynolds number (Re). This thesis adds new loss coefficient data to the open literature, and a new correlation, which will be useful for designing pipelines in industries, as well as contributing to the academic debate in this discipline.
Mbiya, Baudouin Mulumba. "Predicting pressure losses in straight-through diaphragm valves." Thesis, Cape Peninsula University of Technology, 2007. http://hdl.handle.net/20.500.11838/2168.
Full textThe diaphragm valve traces its origins to ancient Roman and Greek times, where it was used to control water flow and temperature of hot baths (Century-Instruments, 2007). The particularity of this type of valve is the presence of a diaphragm or membrane which controls the flow. Over the years, the design of this type of valve has evolved into two major varieties. The first is the "weir" type, more suitable for less viscous fluids and a second is the "straight-through" type, suitable for suspensions. This study is focused on the straight-through. With the widespread use of such valves in the mining and mineral processing operations and other industrial applications, although there has been improvement in the selection of the diaphragms and body materials of the valves, as well as actuation methods, improvements were not accompanied by thorough hydraulic investigation to determine the method of calculating the additional head loss caused by the presence of diaphragm valves in pipelines, and in particular for the laminar flow of non-Newtonian fluids. The limited correlations available, such as Hooper's (1981), Perry's (1997) and Miller's (1990) are valid only for Newtonian fluids. Furthermore they are classified as Class 3 (Miller, 1990) which means they are not corroborated in other independent studies. BM
Schmit, Brian David. "Electrical activation of the diaphragm using epimysial electrodes." Case Western Reserve University School of Graduate Studies / OhioLINK, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=case1062594358.
Full textKabwe, Aime Mume. "Non-newtonian loss coefficient for Saunders diaphragm valves /." [S.l. : s.n.], 2009. http://dk.cput.ac.za/cgi/viewcontent.cgi?article=1008&context=td_cput.
Full textOguoma, Onywuchi N. "Analysis and procedures for design of diaphragm chucks." Thesis, Loughborough University, 1985. https://dspace.lboro.ac.uk/2134/25513.
Full textHamilton, Kent Anthony. "Improvements to the Design of a Flexible Diaphragm for use in Pressure Wave Generators for Cryogenic Refrigeration Systems." Thesis, University of Canterbury. Mechanical Engineering, 2013. http://hdl.handle.net/10092/7950.
Full textYarber, Caroline Nicole. "Experimental Determination of the Stiffness and Strength of Continuity Tie Connections in Large Wood Roof Dipahragms, and Impact on the Collective Chord Model." DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/846.
Full textLau, Siu Kei. "Fully coupled numerical analysis of a diaphragm wall construction." Thesis, University of Macau, 2009. http://umaclib3.umac.mo/record=b2099635.
Full textWong, Sio Leong. "Field monitoring of a diaphragm wall construction in Macau." Thesis, University of Macau, 2009. http://umaclib3.umac.mo/record=b2099642.
Full textPaquette, Jocelyn. "Seismic testing of unreinforced masonry building with flexible diaphragm." Thesis, University of Ottawa (Canada), 2002. http://hdl.handle.net/10393/6314.
Full textGauthier, Alain P. "Structure and function of the fresh and fatigued diaphragm." Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=41596.
Full textSharshar, Tarek. "Cortical control of the diaphragm : insights from transcranial stimulation." Thesis, Imperial College London, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.417110.
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