Spelling suggestions: "subject:"aerodynamicresistance"" "subject:"microresistance""
11 |
Estimativa da eficiência do ensaio SPT através da execução da prova de carga estática sobre o amostrador / Estimation of the efficiency in SPT test through static load tests to the samplerPablo Cesar Trejo Noreña 29 July 2011 (has links)
O ensaio de simples reconhecimento com o SPT é um dos mais utilizados para investigação do subsolo nos EUA e no Brasil. Os dados obtidos com este ensaio dinâmico, tais como o índice de resistência à penetração NSPT, classificação do solo e nível freático são usados por diferentes métodos para estimativa de capacidade de carga de fundações rasas e profundas. Para um mesmo solo, o índice NSPT pode ser diferente se diferentes equipamentos forem usados devido ao fato de que diferentes equipamentos de SPT mostram diferentes níveis de eficiência. Em vista disso, uma alternativa para estimar a eficiência do ensaio SPT é utilizando-se o ensaio de prova de carga estática sobre o amostrador. Este ensaio foi implementado para poder avaliar a eficiência do ensaio SPT. Para este fim, foram executados 13 ensaios dinâmicos e 13 ensaios estáticos no campus experimental do Laboratório de Engenharia Civil da UNESP (Bauru). Para estimar a eficiência do ensaio SPT através do ensaio dinâmico, um sistema de aquisição analógico-digital foi utilizado para obter registros de aceleração e força na seção localizada junto ao amostrador SPT. O ensaio dinâmico foi modificado para utilizar várias energias potenciais nominais do martelo e sistemas de elevação. A determinação da eficiência do ensaio através da execução da prova de carga estática foi obtida com base no princípio de Hamilton. Adicionalmente, realizando-se a comparação entre o comportamento de carregamento dinâmico e estático, pode-se obter a resistência estática do sistema amostrador-solo. Esta resistência é calculada utilizando a base de dados obtidas no campo e a aplicação de vários métodos de estimativa como: Aoki et al.(2007), De Souza (2009) e Odebrecht (2003). Os resultados da estimativa da eficiência através do ensaio de prova de carga estática sobre o amostrador mostraram-se consistentes em relação aos valores obtidos com o ensaio dinâmico. Concluiu-se que a execução do ensaio de prova de carga estática sobre, o amostrador é uma alternativa simples e econômica para obter a eficiência do SPT. / The Standard Penetration Test, SPT, is one of the most used one for subsoil information in the USA and Brazil. The data obtained in this dynamic test, such as the penetration resistance index, NSPT, the soil classification and phreatic level are used by different methods to estimate the shallow and deep foundations load capacity. For the same soil, the index NSPT can be different if different equipments are used, because different SPT equipments show different efficiency levels. Having this in mind, an alternative to estimate the essay efficiency of the SPT test is using the static load test (SLT) to the sampler. This test was implemented in order to evaluate the efficiency of SPT. To do so, 13 dynamic tests and 13 static tests were performed in the experimental campus of the State University of São Paulo at Bauru (Unesp- Bauru-Brazil). To estimate the efficiency of the SPT test through the dynamic test, a data acquisition system was used to register accelerations and forces at the located section close to the sampler SPT. The dynamic test was modified so that it would be possible to use many nominal potential energy of the hammer and elevation systems. The estimation of the efficiency made through the SLT tests was based on Hamilton\'s principle. Furthermore, by comparing the dynamic and static behavior, we can get the soil-sampler interface static resistance. This resistance is calculated by using the field data through various estimation methods such as Aoki\'s (2007), De Souza\'s (2009) and Odebrecht\'s (2003). The estimates of the efficiency obtained through SLT test were found to be consistent with those obtained through the SPT modified tests. We conclude that SLT is a simple and non-expensive alternative to obtain the efficiency of SPT equipment.
|
12 |
Determinação do limiar de anaerobiose (LA) pela variabilidade da frequência cardíaca (VFC) durante um protocolo de exercício físico resistido incremental: uma população de pacientes coronariopatas com perfil de funcionalidade e incapacidade traçados pela Classificação Internacional de Funcionalidade, Incapacidade e Saúde (CIF) / Determination of anaerobic threshold (AT) by heart rate variability (HRV) during an incremental resistance exercise protocol: a population of coronary artery disease (CAD) patients with functioning and disability profile set by the International Classification of Functioning, Disability and Health (ICF)Milena Pelosi Rizk Sperling 25 February 2015 (has links)
A Reabilitação Cardíaca (RC) composta de exercícios puramente dinâmicos (EPD) tem sido fortemente recomendada para pacientes com doença arterial coronariana (DAC). Contudo, os exercícios resistidos devem ser incluídos como parte de um programa formal, uma vez que contribuem para promover ganhos nas atividades de vida diária e assim na qualidade de vida (QV). Estudos recentes têm mostrado que a magnitude das respostas metabólicas e autonômicas cardíacas durante o exercício resistido dinâmico (ERD) também está associada com a determinação do limiar de anaerobiose (LA), o qual é um importante parâmetro para determinar a intensidade no EPD. Diante disso, não há informações sobre essas respostas metabólicas e autonômicas no ERD, para pacientes com DAC. Adicionalmente, pouco é sabido acerca da avaliação da funcionalidade/incapacidade percebidos por estes pacientes já incluídos em programas formais de RC, podendo ampliar informações para a tomada de decisões neste processo. Portanto, este estudo propõe ampliar o corpo do conhecimento acerca de duas vertentes, sendo uma mais fisiológica e outra abordagem mais ampliada, contendo aspectos bio-psico-sociais, Objetivamos 1) Determinar o LA pela variabilidade da frequência cardíaca (VFC) durante um protocolo de ERD, numa população diagnosticada com DAC, participante de um programa de RC composto somente de EPD; e 2) Aplicar a CIF (Classificação Internacional de Funcionalidade, Incapacidade e Saúde), tendo como base a vinculação da mesma com a QV auto-percebida, com o propósito de investigar se o programa formal de RC pode produzir impacto nos desfechos multidemensionais de funcionalidade e incapacidade. Vinte pacientes (idade: 63±7 anos) com DAC (FEVE: 60±10%), apresentando boa capacidade funcional e bom prognóstico, realizaram um protocolo de ERD incremental no leg-press. O protocolo iniciava em 10% de l-RM (repetição maxima), com subsequêntes aumentos de 10% até a exaustão física. A variabilidade da frequência cardíaca (VFC), através dos indices lineares (rMSSD e RMSM) e não-lineares (SD1, SD2, SD1/SD2), bem como o lactato sanguíneo, foram determinados no repouso e durante o ERD. Funcionalidade e incapacidade do grupo foram avaliadas através da aplicação do Processo de Vinculação entre o SF-36 com a CIF. ANOVA para medidas repetidas, análise de Bland-Altman, coeficientes de correlação de Pearson e estatística descritiva foram empregados. Admitiu-se nível de significância de 95%. Foram encontradas significativas alterações na VFC e lactato sanguíneo a partir de 30% de 1-RM (p<0.05). Análise de Bland-Altman revelou boa concordância entre limiar de lactato (LL) e limiar de rMSSD (LrMSSD), e de SD1 (LSD1). As cargas relativas obtidas (a partir de 1-RM) no LL, LrMSSD e LSD1 não diferiram (29%±5; 28%±5; 29%±5, respectivamente). A vinculação entre o SF-36 e a CIF permitiu detalhar uma relação de \"Funções corporais\" e principalmente as \"Atividades e Participações\" acometidas pela doença, bem como o grau de problemas/prejuízo destas, mesmo após o programa de RC. Concluímos que o uso da VFC durante o ERD poderia ser um método não-invasivo viável na prática clínica para determinar o LA em pacientes com DAC, auxiliando na definição de parâmetros de intensidade de exercício seguros e apropriados. Além disso, a funcionalidade e incapacidade de pacientes coronariopatas, percebidos sob o seu próprio ponto de vista, poderiam ser avaliadas utilizando-se o SF-36 sob o escopo da CIF, adicionando informações complementares ao processo da RC. / Cardiac Rehabilitation (CR) composed of dynamics purely exercises (DPE) has been strongly recommended for patients with coronary artery disease (CAD). However, resistance training should be included as part of a formal program, since they contribute to promote gains in daily activities and thus the quality of life (QoL). Recent studies have shown that the magnitude of the cardiac, metabolic, and autonomic responses during dynamic resistance exercise (DRE) is associated with the determination of the anaerobic threshold (AT), which is an important parameter to determine the intensity during DPE. Therefore, there is no information about these metabolic and autonomic responses in resistance exercise for patients with CAD. In addition, little is known about the assessment of functioning/disability perceived by these patients already included in formal CR programs, which may extend information for decision-making in this processo Therefore, this study proposes to extend the body in the knowledge of two approaches, with a more physiological and other broader approach, containing bio-psycho-social aspects. We aimed to 1) Determine the A T by heart rate variability (HRV) during an DRE protocol in a population diagnosed with CAD who participated in a CR program with DPE only; and 2) Apply the ICF (International Classification of Functioning, Disability and Health), based on the binding of the same with self-perceived QoL (SF-36), in order to investigate whether the formal RC program may have an impact on multidemensionais outcomes of functionality and disability. Twenty men (age: 63±7 years old) with CAD (LVEF: 60±10%), with good functional capacity and good prognosis, underwent a DRE incremental protocol on leg press until maximal exertion. The protocol began at 10% of 1-RM (repetition maximum), with subsequent increases of 10% until maximal exhaustion. Heart rate variability (HRV) indices from Poincaré plots (SD1, SD2, SD1/ISD2) and time domain (rMSSD and RMSM), as well as blood lactate were determined at rest and during PRE. Functioning and disability were assessed by the linking process between the SF-36 and the ICF. ANOVA for repeated measures, Bland-Altman analysis, Pearson correlation coefficients, and descriptive statistics were used for statistical analysis. The significance level accepted was 95%. Significant alterations in HRV and blood lactate were observed from 30% of 1 RM (p<0.05). Bland- Altman analysis demonstrated a consistent agreement between blood lactate threshold (LT) and rMSSD threshold (rMSSDT) and LT with SD1 threshold (SD1T). Relative values of 1-RM in all LT, rMSSDT and SD1T did not differ (29% ± 5 vs 28% ± 5 vs 29% ± 5, respectively). Finally, the assessment of functioning and disability using the SF-36 and ICF, allowed to list in more detail the \"Body functions\" and especially the \"Activities and Participation\" affected by the disease, as well as the degree of problems/impairments of these aspects, even after the RC program. In conclusion, HRV during DRE could be a feasible noninvasive method in clinical settings to determine AT in CAD patients for planning safe and appropriaje exercise intensities during CR. Moreover, the functioning and disability of coronary patients, perceived under their own point of view, could be assessed using the SF-36 under the scope ofthe lCF, adding supplementary information to the CR process.
|
13 |
Characterization of Two Vernier-Tuned Distributed Bragg Reflector (VT-DBR) Lasers Used in Swept Source Optical Coherence Tomography (SS-OCT)Bergdoll, Greg M 01 June 2015 (has links) (PDF)
Insight Photonic Solutions Inc. has continued to develop their patented VT-DBR laser design; these wavelength tunable lasers promise marked image-quality and acquisition time improvements in SS-OCT applications.
To be well suited for SS-OCT, tunable lasers must be capable of producing a highly linear wavelength sweep across a tuning range well-matched to the medium being imaged; many different tunable lasers used in SS-OCT are compared to identify the optimal solution.
This work electrically and spectrally characterizes two completely new all-semiconductor VT-DBR designs to compare, as well. The Neptune VT-DBR, an O-band laser, operates around the 1310 nm range and is a robust solution for many OCT applications. The VTL-2 is the first 1060 nm VT-DBR laser to be demonstrated. It offers improved penetration through water over earlier designs which operate at longer wavelengths (e.g. - 1550 nm and 1310 nm), making it an optimal solution for the relatively deep imaging requirements of the human eye; the non-invasive nature of OCT makes it the ideal imaging technology for ophthalmology.
Each laser has five semiconductor P-N junction segments that collectively enable precise akinetic wavelength-tuning (i.e. - the tuning mechanism has no moving parts). In an SS-OCT system utilizing one of these laser packages, the segments are synchronously driven with high speed current signals that achieve the desired wavelength, power, and sweep pattern of the optical output.
To validate the laser’s fast tuning response time necessary for its use in SS-OCT, a circuit model of each tuning section is created; each laser section is modeled as a diode with a significant lead inductance. The dynamic resistance, effective capacitance, and lead inductance of this model are measured as a function of bias current and the response time corresponding to each bias condition is determined.
Tuning maps, spectral linewidths, and side-mode suppression ratio (SMSR) measurements important to SS-OCT performance are also collected.
Measured response times vary from 700 ps to 2 ns for the Neptune and 1.2 to 2.3 ns for the VTL-2. Linewidth measurements range from 9 MHz to 124 MHz for the Neptune and 300 kHz to 2 MHz for the VTL-2. SMSR measurements greater than 38 dB and 40 dB were observed for the Neptune and VTL-2, respectively. Collectively, these results implicate the VT-DBR lasers as ideal tunable sources for use in SS-OCT applications.
|
14 |
Auswirkungen der Ultrafiltration auf die Lungenfunktion bei Kindern nach Korrektur eines angeborenen HerzfehlersRichter, Jost Wigand 14 December 2001 (has links)
Das mit dem kardiopulmonalen Bypass assoziierte kapilläre Leck bei Operationen am offenen Herzen führt zu einem Anstieg des totalen Wassergehalts des Körpers, wobei es vor allem zu einer pulmonalen sowie myokardialen Ödementwicklung kommt. Mit der von Naik, Knight und Elliott (1991) hinsichtlich Filterposition und Filtrationszeitpunkt beschriebenen modifizierten Form der Ultrafiltration unmittelbar nach Abgang vom Bypass konnte eine markante Reduzierung der mit dem Bypass assoziierten Flüssigkeitsakkumulation sowie eine unmittelbare Verbesserung der hämodynamischen Parameter (Herzindex, myokardiale Kontraktilität, verminderter postoperativer Verbrauch inotroper Substanzen) nachgewiesen werden. Ziel vorliegender Studie ist deshalb die Untersuchung der Auswirkung der modifizierten Ultrafiltration auf die Lungenfunktion. Für diese Studie wurden 37 Kinder (Alter 3 Tage bis 92 Monate, Gewicht 3,1 bis 21,3 kg) beobachtet, bei denen die operative Korrektur eines angeborenen Herzfehlers unter Einsatz der Herz-Lungen-Maschine (kardiopulmonaler Bypass mit extrakorporaler Membranoxygenierung) vorgenommen wurde. Bei 27 Kindern wurde nach Abgang von der Herz-Lungen-Maschine die modifizierte Hämofiltration durchgeführt, 10 Kinder dienten als Kontrollgruppe. Bei allen Patienten wurden vor Beginn sowie nach Abschluß des Einsatzes der Herz-Lungen-Maschine, nach der ca. zehn Minuten dauernden modifizierten Ultrafiltration bzw. bei der Kontrollgruppe zu einem vergleichbaren Zeitpunkt ca. zehn Minuten nach Entwöhnung vom kardiopulmonalen Bypass und nach einem weiteren Zeitraum von ca. zehn Minuten mittels dynamischer Lungenfunktionsmessung Parameter der Lungenmechanik (dynamische Compliance und Resistance) sowie Lungenfunktion (alveoloarterielle Sauerstoffdifferenz) bestimmt. Außerdem wurden hämodynamische (arterieller und zentralvenöser Blutdruck) und rheologische Veränderungen (Hämoglobin, Hämatokrit) aufgezeichnet. Bei der modifizierten Ultrafiltration zeigte sich unmittelbar nach Filtrationsende mit dem signifikanten Anstieg der Compliance um 13,9 % ein Effekt, der sich etwa 10 Minuten nach Filtrationsende noch weiter steigerte. Weiterhin konnte ein Abfall der alveoloarteriellen Sauerstoffdifferenz um insgesamt 29,2 % gemessen werden. Es ließ sich jedoch keine proportionale Abhängigkeit zwischen der Ultrafiltratmenge und der Verbesserung der Lungenfunktion nachweisen. Die von anderen Autoren unter modifizierter Ultrafiltration festgestellten Veränderungen der Hämodynamik, wie zum Beispiel der signifikante Anstieg des arteriellen Blutdruckes, oder der rheologischen Veränderungen, wie zum Beispiel ein Anstieg des Hämatokrit-Wertes, ließen sich bestätigen. Die Ergebnisse zeigen, daß durch die modifizierte Technik der Ultrafiltration eine unmittelbare Verbesserung der postoperativen Lungenfunktion erreicht werden kann. / The capillary leak, associated with cardiopulmonary bypass in open heart surgery, causes a rise of total body water resulting in tissue, especially in pulmonary and myocardial edema. The modified ultrafiltration is a new aproach to reduce these edemas, first described by Naik, Knight and Elliot in 1991. With the modification of the postition of the ultrafilter in the bypass circuit and the time of filtration in the first minutes after the patient has been weaned from bypass a significant reduction of the bypass associated fluid accumulation could be shown as well as an improvement of hemodynamics (heart index, myocardial contractility, reduced need of inotopic drugs). To investigate the influence of the modified ultrafiltration on the lung function is the objective of this study. In this study 37 children (aging from 3 days to 92 months, weighting from 3.1 to 21.3 kg) have been examined in cardiac surgery for moderate to severe congenital heart disease with the application of the cardiopulmonary bypass. The effect of modified ultrafiltration, which immediately started after being weaned from the cardiopulmonary bypass, was studied in 27 children, 10 children formed the controll population. In all patients alterations in pulmonary mechanics (dynamic compliance and resistance), in pulmonary function (alveolar-arterial difference of oxygen), in hemodynamics (arterial and central venous blood pressure, heart rate) and in blood values (hemoglobin, hematocrit) could be recorded at frequent intervals. The measurements were done before and after being weaned from bypass, after conclusion of the modified ultrafiltration respectively after a comparable intervall in the control group and about 10 minutes later before the closure of the chest was performed. After the modified ultrafiltration a significant increase of pulmonary compliance of about 13.9 % was observed, an effect, which was further amplified in the next 10 minutes. Furthermore a decrease of alveolar-arterial difference of oxygen of 29.2 % could be shown, but no correlation between the amount of ultrafiltrat and improvement of pulmonary function could be proved. Other findings like a significant increase of arterial blood pressure or an increase of the hematocrit, which were also described by other authors in previous studies, could be confirmed. The results indicate, that by using the modified technique of ultrafiltration an improvement of pulmonary function is achievable.
|
Page generated in 0.0474 seconds