Barrier fabrics laminated with nanofiber membranes are used in protective textiles due to their ability to achieve high breathability or water vapor transmission rate (WVTR) while maintaining required barrier properties. The objective of this thesis is to investigate the factors impacting nanofiber membrane breathability. To achieve this objective, the effect of test conditions on breathability, and the relationship between fiber diameter, web porosity and breathability were explored. Nanofiber membranes were solution-spun by electrospinning from 15wt% and 20wt% PA6 solution concentrations, and by forcespinning from 20wt% and 25wt% concentrations. Three web area densities were made from each spinning method and solution combination: 5GSM, 10GSM and 15GSM. In order to investigate the impact of measurement conditions, breathability of all samples was measured by upright cup method (ASTM E96B) at two relative humidity levels (20% and 50%), and three air flow velocity levels (300fpm, 500fpm and 700fpm). The results showed that WVTR of all samples increased significantly when decreasing humidity or increasing air flow velocity. Webs with a lower density (5GSM or 10GSM) had higher changes of WVTR than those with a higher density (10GSM or 15GSM). These results indicate an interaction between the ambient conditions and the nanoweb structure, whereby conditions that are more conducive to water vapor transmission, such as 20%RH and 700fpm, are more discriminant between membranes. Both electropspun and forcespun membranes processed from the lower concentration solutions (15wt%, and 20wt%, respectively) exhibited smaller fiber diameters and smaller mean pore size. Overall, WVTR values varied with membrane thickness, and with solution concentration following a similar pattern as porosity. These effects were more accentuated for the forcespun samples, which had considerably larger pores (2811-5230nm) than the electrospun counterparts (163-298nm). Furthermore, samples forcespun by 20wt% solution were found to have clearly higher WVTR (1587-2194g/m²/24h at 700fpm) than electrospun samples (1526-1614g/m²/24h at 700fpm). This can be explained by the significant difference of pore size between electrospun and forcespun webs. It was concluded that breathability of forcespun samples, particularly those low density ones, could be effectively adjusted by solution concentration and is more sensitive to change of test conditions than that of electrospun webs. / text

Doctor of Philosophy / Department of Biological and Agricultural Engineering / Naiqian Zhang / An optical sensor for determining water velocity in natural open channels like creeks and rivers has been designed and tested. The sensor consists of a plastic body which is shaped so that water flows through a U-shaped channel into which are mounted LEDs and matching phototransistors at various angles. A small amount of dye is injected into the water just upstream of two sets of LEDs and phototransistors which are spaced 4 cm apart. The time delay between the dye’s effects on these signals depends on water velocity and is determined using a biased cross correlation calculation. In addition to providing velocity, the LEDs and phototransistors can also be used to estimate soil sediment concentration. A previous version of the sensor was tested in enclosed flow to confirm that the general design of the sensor, including LEDs, phototransistors, dye and electronics, would indeed work to detect the velocity of water flowing through the sensor. Although the conditions for the test were unlike those experienced in natural open channels, the ability to catch all the fluid flowing through the sensor provided a simple confirmation of the velocity estimate that was not available in field settings. Further testing in the field then confirmed that the sensor worked in the field but also identified several areas needing improvement. Computational fluid dynamics was used to improve the sensor body. The electronics and program running the sensor were also redesigned. After making these improvements, a new version of the sensor was produced. The testing of the new version of the sensor confirmed its ability to accurately detect velocity in natural open channels. The velocity measurements from this sensor were compared to the commercially available Flowtracker velocity sensor. A regression analysis on the measurements from the two sensors found that the velocity measurements from each sensor were nearly identical across a range of velocities. Other tests established that the electronics and programming running the sensor performed as designed. The development and testing of this sensor has resulted in a system which works in natural open channels like creeks and rivers.

by Leung Chung-chu. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1993. / Includes bibliographical references (leaves 101-107). / ABSTRACT --- p.i / ACKNOWLEDGEMENTS --- p.iii / LIST OF ABBREVIATIONS --- p.iv / LIST OF PUBLICATIONS --- p.v / TABLE OF CONTENTS --- p.vi / Chapter CHAPTER 1 --- Introduction / Chapter 1.1 --- Background of the Rheopneumograph --- p.1 / Chapter 1.2 --- The Electrical Bio-impedance (EBI) technique used in Rheopneumography --- p.2 / Chapter 1.3 --- Problems with analysis of Rheopneumograph --- p.6 / Chapter 1.4 --- The EBI measurement unit --- p.8 / Chapter 1.5 --- Data analysis in Rheopneumography and the electrode design --- p.8 / Chapter 1.6 --- Modelling analysis in Rheopneumography --- p.9 / Chapter 1.7 --- Thesis outline --- p.10 / Chapter CHAPTER 2 --- Improvement to the impedance measurement system / Chapter 2.1 --- Introduction --- p.13 / Chapter 2.1.1 --- The Coherent Detection method in EBI signal --- p.13 / Chapter 2.1.2 --- To discuss the problem in Coherent Detection method --- p.16 / Chapter 2.1.3 --- To discuss the problem in Costas Receiver method --- p.16 / Chapter 2.2 --- The concept of the Amplitude Modulation Receiver --- p.17 / Chapter 2.3 --- EBI measurement unit design using AM receiver technique --- p.18 / Chapter 2.3.1 --- The C-Y receiver --- p.18 / Chapter 2.3.2 --- A simple DC offset adjust circuit --- p.23 / Chapter 2.3.3 --- 555KHz local oscillator and constant current source --- p.25 / Chapter 2.3.4 --- Selection of the low pass filter --- p.29 / Chapter 2.4 --- The characteristic of the whole circuit and performance --- p.32 / Chapter 2.5 --- Discussion --- p.36 / Chapter CHAPTER 3 --- Data analysis in Rheopneumogram / Chapter 3.1 --- Introduction --- p.38 / Chapter 3.2 --- The 5-10 electrode array method applied in Thorax Montage --- p.39 / Chapter 3.2.1 --- The definition of the 5-10 electrode array method --- p.39 / Chapter 3.2.2 --- The advantage of the 5-10 electrode array method --- p.41 / Chapter 3.3 --- Signal analysis in subject-to-subject comparison --- p.41 / Chapter 3.3.1 --- The relationship between the ECG and Rheopneumogram --- p.45 / Chapter 3.4 --- Identification of the best electrode location in Rheopneumograph using Pump-jet model --- p.51 / Chapter 3.4.1 --- The fluid mechanical model device (Pump-jet model) --- p.51 / Chapter 3.4.2 --- Result and discussion --- p.57 / Chapter 3.5 --- Electrical conductivity studies in Silicon fluid-Graphite composites applied in EBI electrode array system --- p.62 / Chapter 3.5.1 --- Experimental procedure and results --- p.63 / Chapter 3.6 --- Discussion --- p.73 / Chapter CHAPTER 4 --- Model analysis for the Impedance Rheopneumogram / Chapter 4.1 --- Introduction --- p.76 / Chapter 4.2 --- Blood flow phenomenon study in Rheopneumogram using Pipeline model --- p.78 / Chapter 4.2.1 --- Model derivation --- p.79 / Chapter 4.2.2 --- Result and discussion --- p.86 / Chapter 4.3 --- Blood velocity study in Rheopneumogram using Pump-jet model --- p.94 / Chapter 4.3.1 --- Result and discussion --- p.94 / Chapter 4.4 --- Conclusion --- p.96 / Chapter CHAPTER 5 --- General discussion and Conclusion --- p.97 / Chapter CHAPTER 6 --- Reference --- p.101 / APPENDICES / Chapter I --- Measurement method in the study --- p.107 / Chapter II --- The simplification of an equation in pump-jet model --- p.109 / Chapter III --- The simplification of an equation in pipeline model --- p.111 / Chapter IV --- Impedance relation between body and electrode --- p.112 / Chapter V --- The procedure of the curve fitting --- p.113

INTRODUÇÃO: O envolvimento vascular tem sido reconhecido como uma importante causa de morbidade e mortalidade na Doença de Behçet (DB), mas a importância de métodos não-invasivos em identificar lesões vasculares precoces ainda não foi bem estabelecida. OBJETIVO: Avaliar as propriedades estruturais e funcionais dos vasos na DB utilizando a medida da velocidade de onda de pulso (VOP) carótido-femoral e a avaliação de carótida pelo echo-tracking system. MÉTODOS: Pacientes com DB sem fatores de risco cardiovasculares tradicionais (hipertensão, diabetes, tabagismo e obesidade) foram selecionados consecutivamente. Todos os pacientes com DB realizaram aferição de VOP e ultrasom de carótida. Pacientes com DB foram divididos de acordo com a presença ou não de envolvimento sistêmico (vascular e/ou ocular e/ou sistema nervoso central) e vascular. Controles saudáveis, pareados para sexo e idade, com os mesmos critérios de exclusão foram selecionados. RESULTADOS: Os vinte e três pacientes com DB (11 homens, média de idade de 35,0±7,6 anos), tiveram níveis significativamente maiores de VOP, comparados ao grupo controle (8,4±1,1 vs. 7,5±1,4 m/s, p=0,017). A espessura íntima-média (594,8±138,6 vs. 561,0±134,2 m, p=0,371), o diâmetro diastólico (6383,7±960,4 vs. 6447,6±1159,7 m, p=0,840), a distensão (401,9±117,7 vs. 337,9±175,3 m, p=0,225) e a distensão relativa (6,2±2,8 vs. 5,4±2,4 m, p=0,293) da artéria carótida foram semelhantes entre os grupos. O grupo com doença sistêmica teve níveis significativamente maiores de VOP (8,7±1,2 vs. 7,8±0,7 m/s, p=0,036) comparado àqueles com manifestação exclusivamente mucocutânea. Pacientes com DB e acometimento vascular tiveram os parâmetros de VOP e echotracking similares aos pacientes sem acometimento vascular, mas apresentaram níveis maiores de colesterol total e LDL (p=0,019 e p=0,012, respectivamente). Uma análise de regressão linear multivariada identificou o nível de triglicerídeos como o mais importante fator associado ao aumento dos níveis de VOP (p=0,001) na DB. CONCLUSÕES: A VOP é mais útil do que o ultra-som de carótida para detectar dano vascular em pacientes com DB e enfatizamos o papel da própria doença em promover essas alterações. Os achados reforçam a necessidade de um controle rigoroso de todos os fatores de risco cardiovasculares na DB, particularmente lipoproteínas / INTRODUCTION: Vascular involvement has been recognized as an important cause of morbidity and mortality in Behçets disease (BD) but the role of noninvasive methods in identify early vascular lesions is not established. OBJECTIVE: To evaluate structural and functional properties of vessels in BD using carotid-femoral pulse wave velocity (PWV) and echo-tracking system. METHODS: BD patients without traditional cardiovascular risk factors (hypertension, diabetes, smoking, and obesity) were consecutively selected. All BD patients performed PWV and carotid ultrasound. BD patients were divided according to the presence or not of systemic (vascular and/or ocular and/or central nervous system involvement) and vascular involvement. Healthy controls age- and sex-matched with the same exclusion criteria were selected. RESULTS: The twenty-three BD patients (11 male, mean age 35.0±7.6 years), had a significantly higher PWV levels compared to control group (8.4±1.1 vs. 7.5±1.4 m/s, p=0.017). Intima-media thickness (594.8±138.6 vs. 561.0±134.2 m, p=0.371), diastolic diameter (6383.7±960.4 vs. 6447.6±1159.7 m, p=0.840), distension (401.9±117.7 vs. 337.9±175.3 m, p=0.225), and relative distension (6.2±2.8 vs. 5.4±2.4 m, p=0.293) were similar in both groups. Multivariate linear regression analysis identified triglycerides as the most important factor in increasing PWV levels (p=0.001) in BD. Systemic disease group had significant higher levels of PWV (8.7±1.2 vs. 7.8±0.7 m/s, p=0.036) compared to those with exclusive mucocutaneous manifestations. BD patients with vascular involvement had similar PWV and echo-tracking parameters compared to those without, but had higher total and LDL cholesterol levels (p=0.019 and p=0.012, respectively). CONCLUSIONS: PWV is more useful than carotid ultrasound in detecting structural and functional vascular damage in BD and emphasize the role of the disease itself in promoting these alterations. Our findings also reinforce the need of a rigorous control of all risk factors in BD, particularly lipoproteins

INTRODUÇÃO: O envolvimento vascular tem sido reconhecido como uma importante causa de morbidade e mortalidade na Doença de Behçet (DB), mas a importância de métodos não-invasivos em identificar lesões vasculares precoces ainda não foi bem estabelecida. OBJETIVO: Avaliar as propriedades estruturais e funcionais dos vasos na DB utilizando a medida da velocidade de onda de pulso (VOP) carótido-femoral e a avaliação de carótida pelo echo-tracking system. MÉTODOS: Pacientes com DB sem fatores de risco cardiovasculares tradicionais (hipertensão, diabetes, tabagismo e obesidade) foram selecionados consecutivamente. Todos os pacientes com DB realizaram aferição de VOP e ultrasom de carótida. Pacientes com DB foram divididos de acordo com a presença ou não de envolvimento sistêmico (vascular e/ou ocular e/ou sistema nervoso central) e vascular. Controles saudáveis, pareados para sexo e idade, com os mesmos critérios de exclusão foram selecionados. RESULTADOS: Os vinte e três pacientes com DB (11 homens, média de idade de 35,0±7,6 anos), tiveram níveis significativamente maiores de VOP, comparados ao grupo controle (8,4±1,1 vs. 7,5±1,4 m/s, p=0,017). A espessura íntima-média (594,8±138,6 vs. 561,0±134,2 m, p=0,371), o diâmetro diastólico (6383,7±960,4 vs. 6447,6±1159,7 m, p=0,840), a distensão (401,9±117,7 vs. 337,9±175,3 m, p=0,225) e a distensão relativa (6,2±2,8 vs. 5,4±2,4 m, p=0,293) da artéria carótida foram semelhantes entre os grupos. O grupo com doença sistêmica teve níveis significativamente maiores de VOP (8,7±1,2 vs. 7,8±0,7 m/s, p=0,036) comparado àqueles com manifestação exclusivamente mucocutânea. Pacientes com DB e acometimento vascular tiveram os parâmetros de VOP e echotracking similares aos pacientes sem acometimento vascular, mas apresentaram níveis maiores de colesterol total e LDL (p=0,019 e p=0,012, respectivamente). Uma análise de regressão linear multivariada identificou o nível de triglicerídeos como o mais importante fator associado ao aumento dos níveis de VOP (p=0,001) na DB. CONCLUSÕES: A VOP é mais útil do que o ultra-som de carótida para detectar dano vascular em pacientes com DB e enfatizamos o papel da própria doença em promover essas alterações. Os achados reforçam a necessidade de um controle rigoroso de todos os fatores de risco cardiovasculares na DB, particularmente lipoproteínas / INTRODUCTION: Vascular involvement has been recognized as an important cause of morbidity and mortality in Behçets disease (BD) but the role of noninvasive methods in identify early vascular lesions is not established. OBJECTIVE: To evaluate structural and functional properties of vessels in BD using carotid-femoral pulse wave velocity (PWV) and echo-tracking system. METHODS: BD patients without traditional cardiovascular risk factors (hypertension, diabetes, smoking, and obesity) were consecutively selected. All BD patients performed PWV and carotid ultrasound. BD patients were divided according to the presence or not of systemic (vascular and/or ocular and/or central nervous system involvement) and vascular involvement. Healthy controls age- and sex-matched with the same exclusion criteria were selected. RESULTS: The twenty-three BD patients (11 male, mean age 35.0±7.6 years), had a significantly higher PWV levels compared to control group (8.4±1.1 vs. 7.5±1.4 m/s, p=0.017). Intima-media thickness (594.8±138.6 vs. 561.0±134.2 m, p=0.371), diastolic diameter (6383.7±960.4 vs. 6447.6±1159.7 m, p=0.840), distension (401.9±117.7 vs. 337.9±175.3 m, p=0.225), and relative distension (6.2±2.8 vs. 5.4±2.4 m, p=0.293) were similar in both groups. Multivariate linear regression analysis identified triglycerides as the most important factor in increasing PWV levels (p=0.001) in BD. Systemic disease group had significant higher levels of PWV (8.7±1.2 vs. 7.8±0.7 m/s, p=0.036) compared to those with exclusive mucocutaneous manifestations. BD patients with vascular involvement had similar PWV and echo-tracking parameters compared to those without, but had higher total and LDL cholesterol levels (p=0.019 and p=0.012, respectively). CONCLUSIONS: PWV is more useful than carotid ultrasound in detecting structural and functional vascular damage in BD and emphasize the role of the disease itself in promoting these alterations. Our findings also reinforce the need of a rigorous control of all risk factors in BD, particularly lipoproteins

Licentiatavhandling (sammanfattning) Linköping : Linköpings universitet, 2009. / Härtill 2 uppsatser.

Diss. (sammanfattning) Göteborg : Univ., 2008. / Härtill 4 uppsatser.

Diss. (sammanfattning) Uppsala : Univ., 2003. / Härtill 5 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2006. / Härtill 4 uppsatser.

Diploma thesis is divided into two parts. The theoretical part deals with natural ventilation and the practical part focuses on the optimization of the ventilation in the original hall using CFD simulation. One of the solutions is proposed in the design part of the diploma thesis.