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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
411

2-D pore and core scale visualization and modeling of immiscible and miscible CO2 injection in fractured systems

Er, Vahapcan 11 1900 (has links)
Pore scale interaction between matrix and fracture during miscible and immiscible CO2 injection was studied experimentally using visual models. Initially, visualization experiments were conducted on 2-D glass bead packed models by injecting n-heptane (solvent) displacing different kinds of processed oil. The focus was on the displacement patterns and solvent breakthrough controlled by matrix-fracture interaction and the pore scale behaviour of solvent-oil interaction for different fracture and injection conditions (rate, vertical vs. horizontal injection) as well as oil viscosity. Besides the visual investigation, effluent was also analyzed to calculate the solvent cut and oil recovery. Next, the process was modeled numerically using a commercial compositional simulator and the saturation distribution in the matrix was matched to the experimental data. The key parameters in the matching process were the effective diffusion coefficients and the longitudinal and transverse dispersivities. The diffusion coefficients were specified for each fluid and dispersivities were assigned into grid blocks separately for the fracture and the matrix. Finally, glass etched microfluidic models were used to investigate pore scale interaction between the matrix and the fracture. The models were prepared by etching homogeneous and heterogeneous micro scale pore patterns on glass sheets bonded together and then saturated with colored n-decane as the oleic phase. CO2 was injected at miscible and immiscible conditions. The focus was on visual pore scale analysis of miscibility, breakthrough of CO2 and oil/CO2 transfer between the matrix and the fracture under different miscibility, injection rate and wettability conditions. / Petroleum Engineering
412

Peripartale hämatologische und klinisch-chemische Blutuntersuchungen zur Frühdiagnostik der Dislocatio abomasi, Gebärparese, Retentio secundinarum und Mastitis bei Milchkühen / Peripartal screenings of haematological and blood chemical parameters for the early diagnosis of abomasal displacement, milk fever, retained placenta and mastitis in dairy cows

Schwartau, Katja 14 February 2012 (has links) (PDF)
Zusammenfassung Katja Schwartau Peripartale hämatologische und klinisch-chemische Blutuntersuchungen zur Frühdiagnostik der Dislocatio abomasi, Gebärparese, Retentio secundinarum und Mastitis bei Milchkühen Medizinische Tierklinik der Veterinärmedizinischen Fakultät der Universität Leipzig Eingereicht im Mai 2011 Bibliographische Angaben 94 Seiten, 22 Abbildungen, 19 Tabellen, 210 Literaturangaben, Schlüsselwörter: Labmagenverlagerung, Gebärparese, Retentio secundinarum, Mastitis, Kuh Produktionskrankheiten haben in den letzten Jahren immer mehr an Bedeutung gewonnen. Diese leistungsassoziierten Bestandserkrankungen tragen wesentlich zur kurzen Nutzungsdauer von ca. 2,5 Jahren der Milchkühe bei. Es ist deshalb besonders wichtig, ihre Prophylaxe einschließlich der Früherkennung in den Vordergrund zu stellen. In der vorliegenden Untersuchung wurden deshalb frühdiagnostische Möglichkeiten der LMV (Labmagenverlagerung), GP (Gebärparese), Retentio sec. (Retentio secundinarum) und Mastitis geprüft. Des Weiteren wurden die Kühe in einer Gruppe „krank“ und einer Gruppe „gesund“ gegenübergestellt, um durch Stoffwechselabweichungen generell subklinische Veränderungen zu erkennen, die Hinweise auf bevorstehende Erkrankungen geben. Besondere Beachtung fand für die Bewertung des Erkrankungsrisikos die odds ratio. In die Untersuchung wurden insgesamt 398 Schwarzbunte Kühe einbezogen. 49 Tiere waren an einer LMV, 121 Tiere an einer GP, 131 an einer Retentio sec. und 119 Tiere an einer Mastitis erkrankt. Im Gruppenvergleich gesund/krank wurden 347 erkrankte Kühe mit 51 klinisch gesunden Tieren verglichen. Es wurden bei allen Kühen 14-7 d a.p. (Tage ante partum) und 3 d p.p. (Tage post partum) Blutproben entnommen. Es wurden Parameter des Energie-, Fett- und Leberstoffwechsels (FFS [Freie Fettsäuren], BHB [ß-0H-Butyrat], Cholesterol, Glucose, Insulin, AST [Aspartat-Amino-Transferase], Bilirubin), des Eiweißstoffwechsels (Albumin, Haptoglobin, TP [Gesamt-Eiweiß], Harnstoff, Kreatinin) und der Leukozyten sowie des Mineralstoffwechsels (Na [Natrium], K [Kalium], Cl [Chlorid], Ca [Calcium], Pi [anorganisches Phosphat], AP [Alkalische Phosphatase]) und der CK [Creatinkinase] bestimmt und mit gesunden Kühen verglichen. 92 Auf das Risiko einer LMV weisen a.p. besonders Konzentrationssteigerungen des Haptoglobins hin. Aber auch die Mediane der Glucose und der AP liegen außerhalb des Referenzbereichs bei Tieren, die später an einer LMV erkranken. Drei d p.p. kommen signifikante Konzentrationsanstiege der FFS, des BHB und des Bilirubin sowie signifikante Konzentrationsabnahmen des Insulin (odds ratio 8,43) bis unter den Normbereich hinzu. Die Aktivitäten der AP und auch die Konzentrationen von Cholesterol und Ca bleiben ebenfalls unter dem Normbereich. Die Mediane der AST-Aktivität und der Haptoglobinkonzentration liegen oberhalb des Referenzbereichs. Auf das Risiko einer GP weisen a.p. und p.p die verminderte AP-Aktivität sowie Konzentrationsanstiege der FFS (odds ratio 1,78) hin. Drei d p.p ergänzen die Konzentrationen des BHB, des Bilirubins und des Haptoglobins (odds ratio 4,59) oberhalb der Referenzbereiche die Veränderungen. Der Median der Insulinkonzentration liegt 3 d p.p. unter dem Referenzbereich. Einer Retentio sec. gehen erhöhte Glucosekonzentrationen a.p. voraus. Der Median der AP-Aktivitäten liegt schon a.p. unter dem Normbereich. Drei d p.p. unterscheidet er sich signifikant von Kühen ohne Retentio sec. Hinweise auf Mastitiden liefern p.p. die Konzentrationen des BHB (odds ratio 1,78). Die Mediane der Glucosekonzentrationen liegen a.p. oberhalb und die der AP-Aktivitäten unterhalb der Referenzbereiche. Drei d p.p. kommen Steigerungen der Haptoglobin-, Glucose- und Bilirubinkonzentrationen sowie Aktivitätssteigerungen der AST bis über den Normbereich hinzu. Als Besonderheit liegen die Ca- und Pi-Konzentrationen aufgrund des geringeren Abflusses bei einer verminderten Milchleistung signifikant über denen der gesunden Kühe. Für die Entstehung postpartaler Erkrankungen generell verdienen die signifikanten Konzentrationssteigerungen der Glucose sowie die Abnahme der AP-Aktivität besondere Beachtung. Das BHB (odds ratio 1,92 a.p.) und die CK (odds ratio 2,17 a.p.) weisen auf ein erhöhtes Krankheitsrisiko hin. Drei d p.p. kommen zu den Veränderungen dieser Parameter noch signifikante Konzentrations- bzw. Aktivitätssteigerungen der FFS, des BHB, der CK, des Bilirubins, der AST und des Haptoglobins (odds ratio 4,61) sowie erniedrigte Ca-Konzentrationen hinzu. Die Untersuchungen haben gezeigt, dass a.p. generell Abweichungen des Energiestoffwechsels und im Besonderen gesteigerte Glucosekonzentrationen sowie erniedrigte AP-Aktivitäten ein erhöhtes Risiko für postpartale Erkrankungen anzeigen. Höhere Aussagekraft besitzen Kontrollen am 3. d p.p. mit den Parametern Insulin (odds ratio 8,4), FFS, BHB und Haptoglobin (odds ratio 4,61), deren Konzentrationen gegenüber gesunden Kühen signifikant abweichen. Ähnlich gute Eignung zeigen, Bilirubin, AST und Ca.
413

ねじり - 軸力負荷における鉄鋼薄肉円管試験片における円孔からの疲労き裂の伝ぱ挙動

田中, 啓介, TANAKA, Keisuke, 秋庭, 義明, AKINIWA, Yoshiaki, 高橋, 晶広, TAKAHASHI, Akihiro, 御厨, 照明, MIKURIYA, Teruaki 06 1900 (has links)
No description available.
414

Begleiterkrankungen bei Kühen mit Dislocatio abomasi unter besonderer Berücksichtigung der Peritonitis

Zwengauer, Rainer 24 June 2010 (has links) (PDF)
Ziel der Untersuchungen war es, klinische Befunde und Laborparameter von Kühen mit Labmagenverlagerung (LMV) zu vergleichen. Dabei wurden besonders Begleit-krankheiten berücksichtigt. Trotz standardisierter Methoden, gibt es nach der Lab-magenreposition immer wieder Fälle, in denen keine oder eine verzögerte Genesung eintritt. Inflammatorische, intraabdominale Prozesse wurden vermutet, konnten aber nur schwer diagnostiziert werden. Deshalb galt der Untersuchung des Bauchpunkta-tes und der Peritonitisdiagnostik besonderes Interesse. In die Untersuchung gingen 100 Kühe mit LMV ein. Zum Zeitpunkt der OP und bei der Nachuntersuchung nach 7-12 Tagen wurden Blut und Bauchpunktatproben ent-nommen. Die Blutproben dienten der hämatologischen Untersuchung und der Analy-se des Energiestoffwechsels (FFS, BHB, Bilirubin, Cholesterol), des Proteinstoff-wechsels (Gesamtprotein, Albumin, Haptoglobin, Harnstoff, Creatinin), der Leber-funktion (GLDH, GGT, AST, LDH) und des Mineralstoffwechsels (Ca, K, Mg, Cl, Na, P, Fe). Das Bauchpunktat wurde zytologisch, bakteriologisch (Gram-Färbung) sowie klinisch-chemisch (Protein, Albumin, Harnstoff, Glucose, Cholesterol, Haptoglobin, AP, AST, CK, LDH) analysiert. Statistisch wurden die Gruppen LMV-links (n=80), LMV-rechts (n=20) und LMV-gesamt Gruppe (n=100) sowie die Gruppen ohne Begleitkrankheiten (n=31), Metritis (n=38), Erkrankungen des Bewegungsapparates (n=31), Mastitis (n=19), Enteritis (n=11), Pneumonie (n=6), Peritonitis (n=4) und Kühe mit Geburtsverletzung (n=3) zum Zeitpunkt der OP und zum Zeitpunkt der Nachuntersuchung verglichen. Die Laborparameter im Bauchpunktat zeigten zum Zeitpunkt der OP keine auffälligen Abweichungen. Stärkere Veränderungen konnten bis zur Nachuntersuchung 7-12 Tage p. OP festgestellt werden. Die zur Peritonitisdiagnostik relevanten Parameter Gesamtleukozyten, neutrophile Granulozyten, eosinophile Granulozyten und Ge-samtprotein stiegen an (p<0,0001). Die Befunde der verschiedenen Begleitkrankhei-ten unterschieden sich nur unwesentlich (p>0,05). Der Nachweis von Bakterien im Bauchpunktat korrelierte nicht mit der Begleitkrankheit Peritonitis. Der bei der hämatologischen Blutanalyse bestehende hohe Anteil an Kernlinksver-schiebungen zum Zeitpunkt der OP hing mit den diagnostizierten Begleitkrankheiten zusammen. Der Anteil stabkerniger Granulozyten lag bei allen Begleitkrankheiten Gruppen über dem Referenzwert, der der Metritis Gruppe mit 0,53 G/l signifikant (p<0,05) höher als bei der Gruppe ohne Begleitkrankheit (0,18 G/l). Der Energiestoffwechsel der Kühe mit LMV war stark belastet. Die FFS- und BHB-Konzentrationen waren zurzeit der OP über den Referenzwert erhöht, fielen aber bis zur Nachuntersuchung bis in den Normbereich (p<0,0001). Der Vergleich der Be-gleitkrankheiten brachte keine signifikanten Differenzen. Zurzeit der OP wurden für beide LMV-Gruppen über den Referenzwert erhöhte Hap-toglobinkonzentrationen sowie Creatinkinase-, AST- und LDH- Aktivitäten bestimmt. Kalium und Magnesium zeigten bei Kühen mit LMV zum Zeitpunkt der OP erniedrigte Konzentrationen. Die Kaliumkonzentrationen beider LMV-Gruppen normalisierten sich bis zur Nachuntersuchung (p<0,0001). Der Vergleich der Stoffwechselparameter bei den unterschiedlichen Begleitkrankhei-ten zurzeit der OP ergab nur für die Metritis-Gruppe gegenüber der Gruppe ohne Be-gleitkrankheit signifikante Differenzen: niedrigere Harnstoff- (p<0,05), Cholesterol-, Albumin- und Magnesiumkonzentrationen (p<0,0001) sowie höhere Bilirubin- und Haptoglobinkonzentrationen (p<0,05). Schlussfolgernd ist festzustellen: 1. Kühe mit LMV leiden häufig an weiteren Erkrankungen, in erster Linie an Metritis und an Erkrankungen des Bewegungsapparates. 2. Häufig konnte eine Entgleisung des Energiestoffwechsels mit erhöhten FFS- und BHB-Konzentrationen festgestellt werden, die sich nach Reposition des verlagerten Organs unter Therapie wieder normalisierte. 3. Die Anzahl der Begleitkrankheiten hatten keine statistisch nachweisbaren Auswirkungen auf den Behandlungserfolg der operierten LMV-Kühe, wobei für die Rekonvaleszenz der Kühe eine, den jeweiligen Begleitkrankheiten angepasste Behandlung von Bedeutung ist. Die Begleitkrankheit Metritis zeigte die deutlichsten Abweichungen bei der Untersuchung der Stoffwechselparameter. Es konnte kein statistischer Zusammenhang zwischen der Begleitkrankheit Peritonitis und der verstorbenen Patientengruppe nachgewiesen werden. 4. Die zur Peritonitisdiagnostik gewonnene Bauchhöhlenflüssigkeit war post OP starken Veränderungen unterworfen. Diese Veränderungen zeigten sich vor allem in stark gestiegenen Leukozytenzahlen und erhöhten Proteinkonzentrationen.
415

Competition, Coexistence and Character Displacement : In a Young Avian Hybrid Zone

Vallin, Niclas January 2011 (has links)
This thesis investigates the ecological and evolutionary implications of a recent secondary contact between two closely related bird species: collared (Ficedula albicollis) and pied (F. hypoleuca) flycatchers. Collared flycatchers started to colonize the Swedish island of Öland, where pied flycatchers were already present, in the late 1950s-early1960s. My major aims were to investigate which factors are acting against versus for long-term coexistence between the two species. Specifically, I investigated the relative importance of allopatric divergence, interspecific competition, hybridization and learning in promoting or inhibiting coexistence. The combined effects of interspecific competition and hybridization drives pied flycatchers towards local extinction in their preferred deciduous habitat. However, my results also show that pied flycatchers are better able to tolerate harsh environmental conditions. This trade-off between competitive ability and resilience in the face of harsh conditions facilitates a regional coexistence between the species. Coexistence is furthermore favoured by competition-mediated divergence in breeding habitat choice, timing of breeding and male breeding plumage colouration. Due to interspecific competition, male pied flycatchers are forced to breed in a more mixed forest type with a later peak in food abundance, which is accompanied by a divergence in breeding time between the two species. In areas shared with collared flycatchers, male pied flycatchers with brown plumage coloration, most divergent from that of collared flycatchers, are favoured by selection. In addition to facilitating coexistence, the observed shift in habitat occupancy increases reproductive isolation between the two species. By using cross-fostering experiments I demonstrate that natal habitat imprinting has the potential to additionally speed up habitat segregation. Finally I show that hybrid nestlings express an intermediate response to harsh environments, indicating that another aspect of ecological-based selection may be important in reproductive isolation between the species. In summary, my results show that adaptations during historic allopatry are important both in facilitating coexistence as well as in providing a foundation for further ecological divergence at secondary contact. This is of relevance today as many species are shifting their distributions in response to habitat disturbance and global warming.
416

Analysis of three ventilation systems in an office: Mixing, displacement and confluent jet ventilation system. : Analysis of temperature gradient, tracer gas and thermal comfort.

Peña Malo, Julio J., Panjkov Zafra-Polo, Igor January 2013 (has links)
Scandinavian countries have always been the first in investigation and development of new ventilation systems. In the last years, engineers from Finland and Sweden are studying a new ventilation system known “Confluent jet ventilation system” which is trying to improve displacement and mixing results. The aim of this thesis master is to study the behaviour of three different ventilation systems, mixing ventilation, displacement ventilation and confluent jet ventilation, in an office room by mean of three analysis, temperature gradient analysis, tracer gas analysis and thermal comfort analysis, and to compare them to know if the new one, confluent jet, increases the performance of mixing or displacement ventilation system. In case of confluent jet ventilation system, there were two different cases: one with the supply air device at 2.2m high, and the other with it at 1.7m high to compare which one was the correct position and gets the best results. For each studied system 3 different cases were analyzed, having the same parameters each one of them for the three ventilation systems.The measurements were taken in an office room located in the laboratory of the University of Gävle, Högskolan I Gävle, in collaboration with the Finnish company specialized in ventilation systems, Stravent. For temperature gradient analysis, ten sensors took temperatures from the low level, 0.1m high, to the top level of the room, 2.4m, during all the time that the other measurements were being taken. For tracer gas analysis, a data logger took measurements of the contaminant concentration, N2O, from when the contaminant was thrown into the room until it disappeared following a Decay curve. Lastly, in thermal comfort analysis 4 transducers took measurements each 12 minutes of air temperature, operative temperature, air velocity and air humidity are measured in 6 different points inside the office room and at 3 different heights, 0.1m, 1.1m and 1.7m. After analyzing the results of temperature gradient, tracer gas and thermal comfort the best results were obtained by confluent jet system with the supply air device at 2.2m in case of temperature gradient, since the difference of temperatures between the low and the top level were the minimum and contaminants and indoor air were not in a homogeneous mixing. In case of tracer gas, the results about air change efficiency were not the expected because they showed a well-mixed situation for every system and it should not have been like that. It was caused for the influence of a cooling system situated in the ceiling of the room and the temperature difference between inside and outside the room that affected more than expected. Finally, in thermal comfort analysis, the best results were obtained by confluent jet ventilation, therefore in case of the supply air device at 2.2m and in case of it at 1.7m. To sum up, taking account the results achieved, the confluent jet ventilation got the best results and showed that it is a new ventilation system that must be taken in consideration in the following buildings. Between supply air device at 2.2m and 1.7m the results were very similar, but a bit better in case of the highest height.
417

Spatial perception and progressive addition lenses

Hendicott, Peter Leslie January 2007 (has links)
Progressive addition lenses (PALs) are an increasingly preferred mode for the correction of presbyopia, gaining an increased share of the prescription lens market. Sales volumes are likely to increase over the next few years, given the increasing cohort of presbyopic patients in the population. This research investigated adaptation to PAL wear, investigating head movement parameters with and without progressive lenses in everyday visual tasks, and examined symptoms of spatial distortions and illusory movement in a crossover wearing trial of three PAL designs. Minimum displacement thresholds in the presence and absence of head movement were also investigated across the lens designs. Experiment 1 investigated head movements in two common visual tasks, a wordprocessing copy task, and a visual search task designed to replicate a natural environment task such as looking for products on supermarket shelving. Head movement parameters derived from this experiment were used to set head movement amplitude and velocity in the third experiment investigating minimum displacement thresholds across three PAL designs. Head movements were recorded with a Polhemus Inside Track head movement monitoring system which allows real time six degrees of freedom measurement of head position. Head position in azimuth, elevation and roll was extracted from the head movement recorder output, and data for head movement angular extent, average velocity (amplitude/duration) and peak velocity were calculated for horizontal head movements Results of the first experiment indicate a task dependent effect on head movement peak and average velocity, with both median head movement average and peak velocity being faster in the copy task. Visual task and visual processing demands were also shown to affect the slope of the main sequence of head movement velocity on head movement amplitude, with steeper slope in the copy task. A steeper slope, indicating a faster head movement velocity for a given head movement amplitude, was found for head movements during the copy task than in the search task. Processing demands within the copy task were also shown to affect the main sequence slopes of velocity on amplitude, with flatter slopes associated with the need for head movement to bring gaze to a specific point. These findings indicate selective control over head movement velocity in response to differing visual processing demands. In Experiment 2, parameters of head movement amplitude and velocity were assessed in a group of first time PAL wearers. Head movement amplitude, average and peak velocity were calculated from head movement recordings using the search task, as in Experiment 1. Head movements were recorded without PALs, on first wearing a PAL, and after one month of PAL wear to assess adaptation effects. In contrast to existing literature, PAL wear did not alter parameters of head movement amplitude and velocity in a group of first time wearers either on first wearing the lenses or after one month of wear: this is due to task related effects in this experiment compared to previous work. Task demand in this experiment may not have required wearers to use the progressive power corridor to accomplish identification of visual search targets, in contrast to previous studies where experimental conditions were designed to force subjects to use the progressive corridor. In Experiment 3, minimum displacement thresholds for random dot stimuli were measured in a repeated measures experimental design for a single vision lens as control, and three PAL designs. Thresholds were measured in central vision, and for two locations in the temporal peripheral field, 30° temporal fixation and 10° above and below the horizontal midline. Thresholds were determined with and without the subjects' head moving horizontally in an approximate sinusoidal movement at a frequency of about 0.7 Hz. Minimum displacement thresholds were not significantly affected by PAL design, although thresholds with PALs were higher than with a single vision lens control. Head movement significantly increased minimum displacement threshold across lens designs, by a factor of approximately 1.5 times. Results indicate that the local measures of minimum displacement threshold determined in this experiment are not sensitive to lens design differences. Sensitivity to motion with PAL lenses may be more a global than a localized response. For Experiment 4, symptoms of spatial distortion and illusory movement were investigated in a crossover wearing trial of three PAL designs, and related to optical characteristics of the lenses. Peripheral back vertex powers of the PALs were measured at two locations in the right temporal zone of the lenses, 15.6 mm temporal to the fitting cross, and 2.7 m above and below the horizontal to the fitting cross. These locations corresponded to the zones of the lenses through which minimum displacement thresholds were measured in the previous experiment. The effect of subjects' self movement on symptoms is able to discriminate between PAL designs, although subjective symptoms alone were not related to the lens design parameters studied. Subjects' preference for one PAL design over the other designs studied in this experiment is inversely related to the effect on subject movement on their symptoms of distortion. An optical parameter, blur strength, derived from the power vector components of the peripheral powers, may indicate preference for particular PAL designs, as higher blur strength values are associated with lower lens preference scores. Head movement amplitude and velocity are task specific, and are also influenced by visual processing demands within tasks. PALs do not affect head movement amplitude and velocity unless tasks are made demanding or performed in less natural situations designed to influence head movement behaviour. Both head movement and PALs have large effects on minimum displacement thresholds; these effects may be due in part to complexity of the subjects' task within the experiment. Minimum displacement thresholds however were not influenced by PAL design. The most sensitive indicator for subject's preference of PALs was the effect of subjects' self movement on their perception of symptoms, rather than the presence of actual symptoms. Blur strength should be further investigated for its role in PAL acceptance.
418

Investigation of the end bearing performance of displacement piles in sand

Xu, Xiangtao January 2007 (has links)
[Truncated abstract] The axial performance of piles in sand remains an area of great uncertainty in geotechnical engineering. Over the years, database studies have shown that the existing method for offshore piles (e.g. API 2000) is unreliable. There is therefore a clear need for an improved predictive method, which incorporates the state-ofthe- art understanding of the underlying controlling mechanisms. This Thesis is dedicated to address the factors influencing the end bearing performance of displacement piles in siliceous sand with a view to proposing and justifying an improved design formulation. Firstly, a database of displacement pile load tests in sand with CPT data was compiled in collaboration with James Schneider (Schneider 2007). It features the widest database with also the latest available pile load test data (e.g. Euripides, Ras Tanajib, Drammen etc) in electronic form. Evaluation of the three new CPTbased methods (Fugro-05, ICP-05 & NGI-05) against this database has revealed a broadly similar predictive performance despite their end bearing formulations being remarkably different. This anomaly promoted the author to extend the database to include additional tests with base capacity measurements to form new base capacity databases for driven and jacked piles, which resulted in the UWA- 05 method for end bearing of displacement piles in sand. This method accounts for the pile effective area ratio, differentiates between driven and jacked piles, and employs a rational qc averaging technique. ... Field tests were performed in Shenton Park, Perth to supplement the database study and, in particular, to examine the effect of the incremental filling ratio (IFR). 10 open-ended and 2 closed-ended piles were tested in compression followed by tension. The test results provide strong support for the UWA-05 method for base capacity evaluation employing the CPT qc values and the effective area ratio. A series of jacked pile tests was carried out on the UWA beam centrifuge, to further explore the factors affecting pile base response. In total, four uniform and four layered centrifuge samples were prepared and tested at various stress levels and relative densities using three separate pile diameters. The resistance ratio (qb0.1/qc,avg) is found to be independent of the absolute pile diameter, effective stress and soil relative density. The tests in layered soil enabled quantification of the reduction in penetration resistance when a pile/cone approaches a weak layer and revealed the significant influence on base stiffness of underlying soft clay layers. The stiffness decay curves (G/GIN vs. w/D, where GIN is initial operational shear stiffness) measured in static load tests were found to vary with ratios of GIN/qc, while there was a unique relationship between G/GIN and qb/qc. A detailed parametric study was carried out (using the FE code PLAXIS) by idealising pile penetration using a spherical cavity expansion analogue in layered soil. The numerical predictions compare well with the centrifuge results and their generalization enabled guidelines to be established for end bearing in layered soil.
419

Lumbar muscle fatigue : analysis of electromyography, endurance time and subjective factors in patients with lumbar disc herniation and healthy subjects /

Dedering, Åsa, January 2002 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 5 uppsatser.
420

The social implications of children's media use

Bickham, David Stephen. Vandewater, Elizabeth A., January 2004 (has links) (PDF)
Thesis (Ph. D.)--University of Texas at Austin, 2004. / Supervisor: Elizabeth A. Vandewater. Vita. Includes bibliographical references. Available also from UMI company.

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