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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.
31

The effect of negative airway pressure on arterial blood gases during endotracheal suctioning

Rux, Marcy. January 1979 (has links)
Thesis (M.S.)--University of Wisconsin - Madison. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 61-63).
32

Aspectos epidemiologicos, clinicos e tratamento broncoscopico da aspiração de corpo estrannho em menores de 14 anos de idade, atendidas em hospitais universitario, no periodo 2000-2005 / Clinical, epidemiological aspects and broncoscopic treatment of foreign body aspiration in under 14 age at a University Hospital from 2000 to 2005

Fraga, Andrea de Melo Alexandre, 1968- 26 February 2007 (has links)
Orientador: Emilio Carlos Elias Baracat / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-09T01:33:11Z (GMT). No. of bitstreams: 1 Fraga_AndreadeMeloAlexandre_M.pdf: 2944008 bytes, checksum: 7cae7c945b29860aec49fb63648bedd5 (MD5) Previous issue date: 2007 / Resumo: A aspiração de corpo estranho (ACE), no trato respiratório, é uma situação potencialmente fatal na faixa etária pediátrica. O objetivo do presente estudo é analisar as manifestações clínicas, achados broncoscópicos e identificar fatores determinantes de complicações na evolução de crianças com idade menor que 14 anos que aspiraram corpo estranho (CE). Foi realizado estudo descritivo e retrospectivo de 69 crianças com CE removido via broncoscopia no período de janeiro de 2000 a dezembro de 2005 na Unidade de Emergência Pediátrica do Hospital de Clínicas da UNICAMP. Para comparação de proporções foi utilizado o teste de Qui-quadrado quando necessário e o valor p<0,05 foi considerado como significativo. A faixa etária variou de oito meses a 12 anos e 75,4% dos pacientes tinham idade menor que três anos. Quarenta e três crianças (62,3%) eram do sexo masculino. A principal queixa foi tosse de início súbito (75,4%) e 40,6% dos pacientes foram admitidas no hospital nas primeiras 48 horas de ocorrência do evento. Insuficiência respiratória aguda foi observado em 29 pacientes (42%). A avaliação radiográfica mostrou alteração em 88,1% dos exames e atelectasia foi o achado mais freqüente (38,8%). O CE estava localizado predominantemente na árvore brônquica direita (55%) e era de origem vegetal em 40,6% dos casos, principalmente feijão e amendoim. A tosse foi um sintoma menos freqüente quando o CE estava localizado na traquéia. Na evolução, 26% dos pacientes apresentaram algum tipo de complicação, principalmente pneumonia e atelectasia (15 casos - 21,7%), sendo estas estatisticamente mais freqüentes em crianças com tempo de aspiração maior que 48 horas. Broncoscopia para remoção do CE foi repetida em cinco casos (7,2%) e todos estes evoluíram com complicações. Ventilação mecânica invasiva foi necessária em sete pacientes (10,1%). Não ocorreu óbito nesta casuística. A história clínica com início súbito de tosse, mesmo sem desconforto respiratório, independente de anormalidade no exame radiográfico, devem ser cuidadosamente considerados no diagnóstico de aspiração de CE e a broncoscopia deve ser indicada. A ocorrência de complicações pulmonares mais graves foi significativamente maior em crianças com longo período de aspiração e quando houve impossibilidade de remoção do CE no primeiro procedimento. A alta prevalência de corpos estranhos de origem vegetal alerta para a necessidade de intensificar programas de prevenção, principalmente dirigidos aos cuidadores de crianças menores de três anos / Abstract: Foreign body (FB) aspiration into the respiratory tract is a potential life-threatening situation in pediatrics. The objective of this study was to analyze clinical manifestations, bronchoscopic findings, as well as to identify important factors with consequent complications in children under 14 years of age with FB aspiration. A descriptive and retrospective review of 69 children who had FB removed via bronchoscopy, from January 2000 to December 2005, was conduced at UER-Ped of HC - UNICAMP. For proportion comparison Chi-square Test was used as needed and p < 0,05 was considered significant. The children ages ranged from 8 months to 12 years and 75.4% were under 3 years old. There were 43 males (62.3%). The main complaint was subtle coughing (75.4%), and 40.6% went to the hospital within the first 48 hours of history. Acute respiratory failure was observed in 29 cases (42%). Radiographic evaluation showed abnormality in 88.1% and atelectasis was the most frequent finding (38.8%). The FB was found mainly in the right bronchial tree (55%) being 40.6% of vegetal origin (especially bean and peanut). Cough was a symptom less common when the FB was in trachea. On follow-up, 26% of the patients presented some sort of complication, mainly pneumonia and atelectasis (15 cases; 21.7%), and these were statistically more frequent in children with time of aspiration longer than 48 hours. Bronchoscopy performed to remove FB was repeated in 5 children (7.2%) and all of them had complications. Mechanical ventilation was needed in 7 patients (10.1%). There were no deaths in this series. Clinical history of sudden coughing, even without respiratory distress, regardless of radiological abnormality, should be carefully considered in the diagnosis of FB aspiration and bronchoscopy should be indicated. Occurrences of severe lung complications were significantly higher in children with longer aspiration time and failure to remove the FB in the first procedure. The high prevalence of vegetal origin FB points out the importance of more prevention programs, aimed mainly at children younger than 3 years old / Mestrado / Pediatria / Mestre em Saude da Criança e do Adolescente
33

Role of dynamic flow in relationships between suction head and degree of saturation.

Mohamed, Mostafa H.A., Sharma, R.S. January 2007 (has links)
No / This paper presents results of the relationship between the degree of saturation and the matric suction head at static equilibrium and during dynamic flow of water using a Buchner funnel and a fully instrumented two-dimensional tank, respectively. The major influences of the dynamic flow on the relationships between the suction head and the degree of saturation are highlighted and discussed. The experimental results show that dynamic flow of water strongly affects the volume of entrapped air. The results also reveal that any scanning curve can be described as two parts, namely, transition and coinciding. The transition curve starts from the recent reversal degree of saturation and continues up to the previous reversal degree of saturation. The shape of the transition curve and the amount of hysteresis are not only a function of the reversal degree of saturation but are also a function of the saturation path history. The experimental results are used to examine the validity of the proposed analytical model by Parker and Lenhard in 1987 for describing the relationships between the degree of saturation and the matric suction head. It was found that Parker and Lenhard¿s model provides a good prediction of the relations provided that care should be taken for the value of the reversal degree of saturation at zero suction head.
34

Effect of compaction pressure on consolidation behaviour of unsaturated silty soil

Estabragh, A.R., Javadi, Akbar A., Boot, John C. January 2004 (has links)
The effect of compaction pressure on subsequent soil behaviour during isotropic consolidation has been investigated by conducting controlled-suction triaxial tests on samples of an unsaturated compacted silty soil. A comprehensive set of laboratory experiments was carried out in a double-walled triaxial apparatus on samples of unsaturated soil that were prepared using two different compaction pressures. The axis translation technique was used for creating the desired suctions in the samples. In the experiments, the soil samples were subjected to isotropic consolidation under constant suctions. The results show that different compaction pressures produce different fabrics in a soil and therefore affect the behaviour of the soil. The results also show that the value of yield stress and the location of the loading¿collapse (LC) yield curve are functions of soil fabric. Furthermore, it is shown that the slopes of normal consolidation lines for densely and loosely compacted samples differ in unsaturated conditions but are the same in saturated soils. A comparison is made between the behaviour of the dense and loose samples, and the difference in the behaviour is explained.
35

Patterns and mechanisms of light non-aqueous phase liquid in unsaturated sand.

Mohamed, Mostafa H.A., Sharma, R.S. January 2003 (has links)
No / The paper presents patterns and mechanisms of light non-aqueous phase liquid (LNAPL) migration in an unsaturated/saturated sand, based on a detailed experimental investigation using a fully instrumented two-dimensional model with dimensions of 120 x 120 x 10 cm. Suction head and degree of saturation were monitored simultaneously using tensiometers and time domain reflectometry (TDR) transducers respectively. LNAPL spills into the unsaturated zone were simulated to investigate the influence of new variables of practical importance, including the spill area, volume of spill and fluctuations of groundwater table, on the patterns of LNAPL migration. The patterns are explained in terms of the relationship between matric suction and degree of saturation. Fluctuations of water level are found to have a major influence on the distribution of LNAPLs in the unsaturated/saturated sand for large volumes of LNAPL spill. Measurements of degree of saturation of water at different levels are used to explain the LNAPL migration. It was found that water suction head was not affected by migrating LNAPL if the degree of saturation of water was above the residual saturation. Results of LNAPL suction head were found to be consistent with the migration patterns. Additionally, the average suction head difference between different levels indicated accurately the direction of LNAPL migration, which was in good agreement with the patterns observed using electronic imaging.
36

Long-term matric suction measurements in highway subgrades

Nguyen, Quan 17 May 2006
The performance of Thin Membrane Surface (TMS) highways is largely controlled by the strength of the subgrade soil which in turn is a function of the soil suction (Fredlund and Morgenstern, 1977). Thermal conductivity suction sensors can be used to indirectly measure in situ matric suction. <p>Thirty two (32) thermal conductivity sensors were installed under Thin Membrane Surface (TMS) in two highway locations; namely, Bethune and Torquay, Saskatchewan, in September 2000. The sensors were installed beneath the pavement, shoulder and side-slope to monitor matric suction and temperature changes with time. The monitoring system at Bethune was damaged after two years of operation. The thermal conductivity sensors at Torquay all appear to have been working well and data are still being collected.<p>Other attempts had been made in the past to use thermal conductivity sensors for field suction measurement, but all were terminated within a short period of time due to limitations associated with the equipment. The long-term suction measurement at the Torquay site is unique and provides valuable field data. <p>This research project presents and interprets the long-term matric suction measurements made between the years 2000 to 2005 at the Torquay site and from 2000 to 2002 at the Bethune site. To help in the interpretation of the data, a site investigation was undertaken along with a laboratory testing program that included the measurement of Soil-Water Characteristic Curves (SWCC). As well, a limited laboratory study was undertaken on several new thermal conductivity matric suction sensors. <p>The matric suction readings in the field showed a direct relationship to rainfall and regional evaporation conditions at the test sites. At the Bethune and Torquay test sites, the changes in matric suctions appeared to be mainly due to the movement of moisture through the edge of the road. Relatively constant equilibrium suctions were encountered under the driving-lanes. Conversely, matric suctions under the side-slopes were found to vary considerably with time and depth. Matric suctions under the driving-lanes ranged from 20 to 60 kPa throughout the years. Matric suctions on the side-slopes changed from 100 to 1500 kPa over the years. <p>The greatest variation of soil suctions occurred in the month of April from location to location in the subgrade. The soil suctions became less variable in June while larger variations again occurred from July to October. <p>The matric suction measurements obtained from the thermal conductivity sensors showed a general agreement with the values estimated using the soil-water characteristic curves, SWCC, measured in the laboratory.
37

Long-term matric suction measurements in highway subgrades

Nguyen, Quan 17 May 2006 (has links)
The performance of Thin Membrane Surface (TMS) highways is largely controlled by the strength of the subgrade soil which in turn is a function of the soil suction (Fredlund and Morgenstern, 1977). Thermal conductivity suction sensors can be used to indirectly measure in situ matric suction. <p>Thirty two (32) thermal conductivity sensors were installed under Thin Membrane Surface (TMS) in two highway locations; namely, Bethune and Torquay, Saskatchewan, in September 2000. The sensors were installed beneath the pavement, shoulder and side-slope to monitor matric suction and temperature changes with time. The monitoring system at Bethune was damaged after two years of operation. The thermal conductivity sensors at Torquay all appear to have been working well and data are still being collected.<p>Other attempts had been made in the past to use thermal conductivity sensors for field suction measurement, but all were terminated within a short period of time due to limitations associated with the equipment. The long-term suction measurement at the Torquay site is unique and provides valuable field data. <p>This research project presents and interprets the long-term matric suction measurements made between the years 2000 to 2005 at the Torquay site and from 2000 to 2002 at the Bethune site. To help in the interpretation of the data, a site investigation was undertaken along with a laboratory testing program that included the measurement of Soil-Water Characteristic Curves (SWCC). As well, a limited laboratory study was undertaken on several new thermal conductivity matric suction sensors. <p>The matric suction readings in the field showed a direct relationship to rainfall and regional evaporation conditions at the test sites. At the Bethune and Torquay test sites, the changes in matric suctions appeared to be mainly due to the movement of moisture through the edge of the road. Relatively constant equilibrium suctions were encountered under the driving-lanes. Conversely, matric suctions under the side-slopes were found to vary considerably with time and depth. Matric suctions under the driving-lanes ranged from 20 to 60 kPa throughout the years. Matric suctions on the side-slopes changed from 100 to 1500 kPa over the years. <p>The greatest variation of soil suctions occurred in the month of April from location to location in the subgrade. The soil suctions became less variable in June while larger variations again occurred from July to October. <p>The matric suction measurements obtained from the thermal conductivity sensors showed a general agreement with the values estimated using the soil-water characteristic curves, SWCC, measured in the laboratory.
38

The effects of scaling on bite force and suction index in the eastern hellbender (Cryptobranchus alleganiensis)

Larghi, Nicholas Patrick 01 January 2013 (has links)
The hellbender (Cryptobranchus alleganiensis) is a salamander that grows over a large range of body sizes (2-74 cm total length) making it an ideal organism for examining the effects of body size on morphology and performance. The goal of this study is to investigate the morphology changes over ontogeny and change in feeding ability. Cryptobranchus feeds on small aquatic insects as juveniles and shifts to crayfish as they get larger. Morphology can be expected to change as an organism grows larger, and because morphology and performance are closely linked, this morphological change can result in a change in feeding ability. Cryptobranchus alleganiensis are primarily aquatic salamanders that utilize both suction feeding and biting behaviors. I hypothesize bite force would increase with positive allometry reflecting a possible dietary shift during ontogeny in which larger Cryptobranchus favor crayfish. Because suction is the primary mode of feeding making it an important aspect of feeding throughout ontogeny, suction index was hypothesized to scale with isometry. Fourteen preserved specimens (11.9-34.5 cm SVL) were used to investigate the effects of scaling on suction potential and estimated bite force. Bite force was calculated using a 3D static equilibrium model and suction potential was calculated as suction index. Bite force scaled with positive allometry allowing the animals to bite harder relative to body mass with increasing body size, and suction index showed no effect of body size. Results of this study indicate that Cryptobranchus alleganiensis maintains suction performance across ontogeny allowing them to generate suction with similar ability ontogenetically, but increases its biting performance to cope with durophagous prey with a possible ontogenetic dietary shift.
39

Evaluation of Testing Methods for Suction-Volume Change of Natural Clay Soils

January 2017 (has links)
abstract: Design and mitigation of infrastructure on expansive soils requires an understanding of unsaturated soil mechanics and consideration of two stress variables (net normal stress and matric suction). Although numerous breakthroughs have allowed geotechnical engineers to study expansive soil response to varying suction-based stress scenarios (i.e. partial wetting), such studies are not practical on typical projects due to the difficulties and duration needed for equilibration associated with the necessary laboratory testing. The current practice encompasses saturated “conventional” soil mechanics testing, with the implementation of numerous empirical correlations and approximations to obtain an estimate of true field response. However, it has been observed that full wetting rarely occurs in the field, leading to an over-conservatism within a given design when partial wetting conditions are ignored. Many researchers have sought to improve ways of estimation of soil heave/shrinkage through intense studies of the suction-based response of reconstituted clay soils. However, the natural behavior of an undisturbed clay soil sample tends to differ significantly from a remolded sample of the same material. In this study, laboratory techniques for the determination of soil suction were evaluated, a methodology for determination of the in-situ matric suction of a soil specimen was explored, and the mechanical response to changes in matric suction of natural clay specimens were measured. Suction-controlled laboratory oedometer devices were used to impose partial wetting conditions, similar to those experienced in a natural setting. The undisturbed natural soils tested in the study were obtained from Denver, CO and San Antonio, TX. Key differences between the soil water characteristic curves of the undisturbed specimen test compared to the conventional reconstituted specimen test are highlighted. The Perko et al. (2000) and the PTI (2008) methods for estimating the relationship between volume and changes in matric suction (i.e. suction compression index) were evaluated by comparison to the directly measured values. Lastly, the directly measured partial wetting swell strain was compared to the fully saturated, one-dimensional, oedometer test (ASTM D4546) and the Surrogate Path Method (Singhal, 2010) to evaluate the estimation of partial wetting heave. / Dissertation/Thesis / Masters Thesis Engineering 2017
40

OPTIMIZATION OF BLOWING AND SUCTION CONTROL ON NACA0012 AIRFOIL USING GENETIC ALGORITHM WITH DIVERSITY CONTROL

Huang, Liang 01 January 2004 (has links)
Active control of the flow over an airfoil is an area of heightened interest in the aerospace community. Previous research on flow control design processes heavily depended on trial and error and the designers knowledge and intuition. Such an approach cannot always meet the growing demands of higher design quality in less time. Successful application of computational fluid dynamics (CFD) to this kind of control problem critically depends on an efficient searching algorithm for design optimization. CFD in conjunction with Genetic Algorithms (GA) potentially offers an efficient and robust optimization method and is a promising solution for current flow control designs. But the traditional binary GA and its operators need to be transformed or re-defined to meet the requirements of real world engineering problems. Current research has combined different existing GA techniques and proposed a realcoded Explicit Adaptive Range Normal Distribution (EARND) genetic algorithm with diversity control to solve the convergence problems. First, a traditional binary-coded GA is replaced by a real-coded algorithm in which the corresponding design variables are encoded into a vector of real numbers that is conceptually closest to the real design space. Second, to address the convergence speed problem, an additional normal distribution scheme is added into the basic GA in order to monitor the global optimization process; meanwhile, design parameters boundaries are explicitly updated to eliminate unnecessary evaluations (computation) in un-promising areas to balance the workload between the global and local searching process. Third, during the initial 20% evolution (search process), the diversity of the individuals within each generation are controlled by a formula in order to conquer the problem of preliminary convergence to the local optimum. In order to better understand the two-jet control optimization results and process, at first, a single jet with a width of 2.5% the chord length is placed on a NACA 0012 airfoils upper surface simulating the blowing and suction control under Re=500,000 and angle of attack 18 degree. Nearly 300 numerical simulations are conducted over a range of parameters (jet location, amplitude and angle). The physical mechanisms that govern suction and blowing flow control are determined and analyzed, and the critical values of suction and blowing locations, amplitudes, and angles are discussed. Moreover, based on the results of single suction/blowing jet control on a NACA 0012 airfoil, the design parameters of a two-jet system are proposed. Our proposed algorithm is built on top of the CFD code, guiding the movement of two jets along the airfoils upper surface. The reasonable optimum control values are determined within the control parameter range. The current study of Genetic Algorithms on airfoil flow control has been demonstrated to be a successful optimization application.

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