The Experts below are selected from a list of 258 Experts worldwide ranked by ideXlab platform
Sehyun Shin - One of the best experts on this subject based on the ideXlab platform.
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Measurements of Blood Viscosity Using a Pressure-Scanning Slit Viscometer
Ksme International Journal, 2004Co-Authors: Sehyun Shin, Yun Hee KuAbstract:A newly designed pressure-scanning slit viscometer is developed to combine an optical device without refraction while measuring blood viscosity over a range of shear rates. The capillary tube in a previously designed capillary viscometer was replaced with a transparent slit, which is affordable to mount optical measurement of flowing blood cells. Using a pressure transducer, we measured the change of pressure in a collecting chamber with respect to the time, p(t), from which the viscosity and shear rate were mathematically calculated. For water, standard oil and whole blood, excellent agreement was found between the results from the pressure-scanning slit viscometer and those from a commercially available rotating viscometer. This new viscometer overcomes the drawbacks of the previously designed capillary viscometer in the measuring whole blood viscosity. First, the pressure-scanning slit viscometer can combine an optical instrument such as a microscope. Second, this design is low cost and simple (i.e., ease of operation, no moving parts, and disposable).
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Measurement of blood viscosity using a pressure-scanning capillary viscometer.
Clinical Hemorheology and Microcirculation, 2004Co-Authors: Sehyun Shin, Yun Hee Ku, Myung Su ParkAbstract:A newly designed pressure-scanning capillary viscometer is extended to measure the viscosity of whole blood over a range of shear rates without the use of anticoagulants in a clinical setting. In the present study, a single measurement of pressure variation with time replaces the flow rate and pressure drop measurements that are usually required for the operation of a capillary tube viscometer. Using a pressure transducer and capillary, we measured the variation of pressure flowing through capillary tube with respect to time, p(t), from which viscosity and the shear rate were mathematically calculated. For water and anticoagulant-added bloods, there was an excellent agreement found between the results from the pressure scanning capillary viscometer and those from a commercially available rotating viscometer. Also, the pressure-scanning capillary viscometer measured the viscosity of whole blood without heparin or EDTA. This new method overcomes the drawbacks of conventional Viscometers in the measurement of whole blood viscosity. First, the pressure-scanning capillary viscometer can accurately and consistently measure the whole blood viscosity over a range of shear rates in less than 2 min without any anticoagulants. Second, this design provides simplicity (i.e., ease of operation, no moving parts, and disposable) and low cost.
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Blood viscosity measurements using a pressure-scanning capillary viscometer
KSME International Journal, 2002Co-Authors: Sehyun Shin, Do Young Keum, Yun Hee KuAbstract:A newly designed pressure-scanning capillary viscometer is extended to measure the viscosity of whole blood over a range of shear rates without the use of anticoagulants in a clinical setting. In the present study, a single measurement of pressure variation with time replaces the flow rate and pressure drop measurements that are usually required for the operation of a capillary tube viscometer. Using a pressure transducer and capillary, we measured the variation of pressure flowing through capillary tube with respect to time, p(t), from which viscosity and the shear rate were mathematically calculated. For water and anticoagulant-added bloods, there was an excellent agreement found between the results from the pressure scanning capillary viscometer and those from a commercially available rotating viscometer. Also, the pressure-scanning capillary viscometer measured the viscosity of whole blood without heparin or EDTA. This new method overcomes the drawbacks of conventional Viscometers in the measurement of whole blood viscosity. First, the pressure-scanning capillary viscometer can accurately and consistently measure the whole blood viscosity over a range of shear rates in less than 2 min without any anticoagulants. Second, this design provides simplicity (i.e., ease of operation, no moving parts, and disposable) and low cost.
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Measurement of blood viscosity using mass-detecting sensor
Biosensors and Bioelectronics, 2002Co-Authors: Sehyun Shin, Do Young KeumAbstract:A newly designed mass-detecting capillary viscometer is extended to measure the viscosity of whole blood over a range of shear rates without the use of anticoagulants in a clinical setting. In the present study as proof of principle, a single measurement of liquid-mass variation with time replaces the flow rate and pressure drop measurements that are usually required for the operation of a capillary tube viscometer. Using a load cell and capillary, we measured the change of mass flowing through capillary tube with respect to the time, m(t), from which viscosity and shear rate were mathematically calculated. For water and adulterated bloods, excellent agreement was found between the results from the mass-detecting capillary viscometer and those from a commercially available rotating viscometer. Also, the mass-detecting capillary viscometer measured the viscosity of unadulterated whole blood without heparin or EDTA. This new method overcomes the drawbacks of conventional Viscometers in the measurement of the whole blood viscosity. First, the mass-detecting capillary viscometer can accurately and consistently measure the unadulterated blood viscosity over a range of shear rates in less than 2 min without any anticoagulants. Second, this design provides simplicity (i.e. ease of operation, no moving parts, and disposable) and low cost. © 2002 Elsevier Science B.V. All rights reserved.
Yun Hee Ku - One of the best experts on this subject based on the ideXlab platform.
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Measurements of Blood Viscosity Using a Pressure-Scanning Slit Viscometer
Ksme International Journal, 2004Co-Authors: Sehyun Shin, Yun Hee KuAbstract:A newly designed pressure-scanning slit viscometer is developed to combine an optical device without refraction while measuring blood viscosity over a range of shear rates. The capillary tube in a previously designed capillary viscometer was replaced with a transparent slit, which is affordable to mount optical measurement of flowing blood cells. Using a pressure transducer, we measured the change of pressure in a collecting chamber with respect to the time, p(t), from which the viscosity and shear rate were mathematically calculated. For water, standard oil and whole blood, excellent agreement was found between the results from the pressure-scanning slit viscometer and those from a commercially available rotating viscometer. This new viscometer overcomes the drawbacks of the previously designed capillary viscometer in the measuring whole blood viscosity. First, the pressure-scanning slit viscometer can combine an optical instrument such as a microscope. Second, this design is low cost and simple (i.e., ease of operation, no moving parts, and disposable).
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Measurement of blood viscosity using a pressure-scanning capillary viscometer.
Clinical Hemorheology and Microcirculation, 2004Co-Authors: Sehyun Shin, Yun Hee Ku, Myung Su ParkAbstract:A newly designed pressure-scanning capillary viscometer is extended to measure the viscosity of whole blood over a range of shear rates without the use of anticoagulants in a clinical setting. In the present study, a single measurement of pressure variation with time replaces the flow rate and pressure drop measurements that are usually required for the operation of a capillary tube viscometer. Using a pressure transducer and capillary, we measured the variation of pressure flowing through capillary tube with respect to time, p(t), from which viscosity and the shear rate were mathematically calculated. For water and anticoagulant-added bloods, there was an excellent agreement found between the results from the pressure scanning capillary viscometer and those from a commercially available rotating viscometer. Also, the pressure-scanning capillary viscometer measured the viscosity of whole blood without heparin or EDTA. This new method overcomes the drawbacks of conventional Viscometers in the measurement of whole blood viscosity. First, the pressure-scanning capillary viscometer can accurately and consistently measure the whole blood viscosity over a range of shear rates in less than 2 min without any anticoagulants. Second, this design provides simplicity (i.e., ease of operation, no moving parts, and disposable) and low cost.
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Blood viscosity measurements using a pressure-scanning capillary viscometer
KSME International Journal, 2002Co-Authors: Sehyun Shin, Do Young Keum, Yun Hee KuAbstract:A newly designed pressure-scanning capillary viscometer is extended to measure the viscosity of whole blood over a range of shear rates without the use of anticoagulants in a clinical setting. In the present study, a single measurement of pressure variation with time replaces the flow rate and pressure drop measurements that are usually required for the operation of a capillary tube viscometer. Using a pressure transducer and capillary, we measured the variation of pressure flowing through capillary tube with respect to time, p(t), from which viscosity and the shear rate were mathematically calculated. For water and anticoagulant-added bloods, there was an excellent agreement found between the results from the pressure scanning capillary viscometer and those from a commercially available rotating viscometer. Also, the pressure-scanning capillary viscometer measured the viscosity of whole blood without heparin or EDTA. This new method overcomes the drawbacks of conventional Viscometers in the measurement of whole blood viscosity. First, the pressure-scanning capillary viscometer can accurately and consistently measure the whole blood viscosity over a range of shear rates in less than 2 min without any anticoagulants. Second, this design provides simplicity (i.e., ease of operation, no moving parts, and disposable) and low cost.
Norman M. Wereley - One of the best experts on this subject based on the ideXlab platform.
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constitutive models of electrorheological and magnetorheological fluids using Viscometers
Smart Materials and Structures, 2005Co-Authors: Young-tai Choi, Seungbok Choi, Norman M. WereleyAbstract:A key aspect of application of electrorheological (ER) and magnetorheological (MR) fluids is the characterization of rheological properties. In this study, two rotational Viscometers to measure the field-dependent flow behavior (shear stress versus shear rate) of ER/MR fluids are theoretically analyzed. One is a rotational coaxial cylinder viscometer, and the other is a rotational parallel disk viscometer. The equations between shear stress and torque as well as shear rate and angular velocity are derived on the basis of the Bingham-plastic, biviscous, and Herschel–Bulkley constitutive models. The shear stress for the rotational coaxial cylinder viscometer can be straightforwardly calculated from the measured torque. However, in order to determine the shear rate, three approximation methods are applied. Meanwhile, the shear stress and shear rate in the rotational parallel disk viscometer can be obtained directly from the torque and angular velocity data. In order to comprehensively understand the flow behavior of ER/MR fluids with respect to the constitutive models, nondimensional analyses are undertaken in this study.
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constitutive models of electrorheological and magnetorheological fluids using Viscometers
Smart Structures and Materials 2003: Damping and Isolation, 2003Co-Authors: Young-tai Choi, Norman M. WereleyAbstract:A key aspect of application of electrorheological (ER) and magnetorheological (MR) fluids is the characterization of rheological properties. For this purpose, two rotational Viscometers are theoretically analyzed. One is a rotational coaxial cylinder viscometer, and the second is a rotational parallel disk viscometer. A key goal is to determine the shear stress and shear rate of ER/MR fluids for both Viscometers from the torque and angular velocity data. To do this, the equations between shear stress and torque as well as shear rate and angular velocity are derived on the basis of the Bingham-plastic, biviscous, and Herschel-Bulkley constitutive models. For simplicity in mathematical form, the Bingham-plastic model is used to describe the flow behavior of ER/MR fluids. The biviscous model characterized by static and dynamic yield stresses is used to capture the preyield behavior. The preyield region where the local shear stress is smaller than the static yield stress has much larger viscosity than the postyield region. In order to account for the shear thinning or thickening in postyield region, the Herschel-Bulkley constitutive model is used in this study. The shear stress for a rotational coaxial cylinder viscometer can be calculated directly from measured torque. However, three approximation methods are applied to determine the shear rate. For rotational parallel disk Viscometers, the shear rate and shear stress can be obtained directly from the torque and angular velocity data. In order to comprehensively understand the flow behavior of ER/MR fluids with respect to the constitutive models, the nondimensional analyses are undertaken in this study.© (2003) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
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Comparative analysis of Bingham characteristics of ER/MR fluids with different Viscometers
Smart Structures and Materials 2002: Damping and Isolation, 2002Co-Authors: Young-tai Choi, Norman M. WereleyAbstract:This paper theoretically presents Bingham characteristics of ER (electrorheological)/MR (magnetorheological) fluids with respect to different rotational Viscometers through comparative analysis. For doing so, two different types of rotational Viscometers are introduced and configured for ER/MR fluids; one is a rotational coaxial cylinder viscometer and the other is a rotational parallel disk viscometer. In order to determine the shear stress and shear rate of fluids tested in both Viscometers, the fundamental equations between shear stress and torque as well as shear rate and angular velocity are derived on the basis of the biviscous constitutive model. The biviscous model is characterized by a yield stress: when the shear stress is less than this yield stress, the preyield viscosity is relatively large compared to the postyield viscosity when shear stress is greater than the yield stress. For rotational coaxial cylinder Viscometers, the shear stress can be calculated directly from the measured torque. However, for the determination of the shear rate, some strategies are required. In this study, different methods of determining the shear rate are developed and their accuracy is assessed. In the case of rotational parallel disk Viscometers, the calculation of the shear rate is straightforward from angular velocity measurements, but the shear stress requires a relatively complicated calculation. In this study, for simplicity, the shear stress is approximated and the error of this approximation is evaluated with respect to important rotational parallel disk viscometer geometry. Finally, the Bingham characteristics of ER/MR fluids at two different rotational Viscometers are theoretically presented and compared in the shear stress vs. shear rate response.
Do Young Keum - One of the best experts on this subject based on the ideXlab platform.
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Blood viscosity measurements using a pressure-scanning capillary viscometer
KSME International Journal, 2002Co-Authors: Sehyun Shin, Do Young Keum, Yun Hee KuAbstract:A newly designed pressure-scanning capillary viscometer is extended to measure the viscosity of whole blood over a range of shear rates without the use of anticoagulants in a clinical setting. In the present study, a single measurement of pressure variation with time replaces the flow rate and pressure drop measurements that are usually required for the operation of a capillary tube viscometer. Using a pressure transducer and capillary, we measured the variation of pressure flowing through capillary tube with respect to time, p(t), from which viscosity and the shear rate were mathematically calculated. For water and anticoagulant-added bloods, there was an excellent agreement found between the results from the pressure scanning capillary viscometer and those from a commercially available rotating viscometer. Also, the pressure-scanning capillary viscometer measured the viscosity of whole blood without heparin or EDTA. This new method overcomes the drawbacks of conventional Viscometers in the measurement of whole blood viscosity. First, the pressure-scanning capillary viscometer can accurately and consistently measure the whole blood viscosity over a range of shear rates in less than 2 min without any anticoagulants. Second, this design provides simplicity (i.e., ease of operation, no moving parts, and disposable) and low cost.
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Measurement of blood viscosity using mass-detecting sensor
Biosensors and Bioelectronics, 2002Co-Authors: Sehyun Shin, Do Young KeumAbstract:A newly designed mass-detecting capillary viscometer is extended to measure the viscosity of whole blood over a range of shear rates without the use of anticoagulants in a clinical setting. In the present study as proof of principle, a single measurement of liquid-mass variation with time replaces the flow rate and pressure drop measurements that are usually required for the operation of a capillary tube viscometer. Using a load cell and capillary, we measured the change of mass flowing through capillary tube with respect to the time, m(t), from which viscosity and shear rate were mathematically calculated. For water and adulterated bloods, excellent agreement was found between the results from the mass-detecting capillary viscometer and those from a commercially available rotating viscometer. Also, the mass-detecting capillary viscometer measured the viscosity of unadulterated whole blood without heparin or EDTA. This new method overcomes the drawbacks of conventional Viscometers in the measurement of the whole blood viscosity. First, the mass-detecting capillary viscometer can accurately and consistently measure the unadulterated blood viscosity over a range of shear rates in less than 2 min without any anticoagulants. Second, this design provides simplicity (i.e. ease of operation, no moving parts, and disposable) and low cost. © 2002 Elsevier Science B.V. All rights reserved.
Young-tai Choi - One of the best experts on this subject based on the ideXlab platform.
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constitutive models of electrorheological and magnetorheological fluids using Viscometers
Smart Materials and Structures, 2005Co-Authors: Young-tai Choi, Seungbok Choi, Norman M. WereleyAbstract:A key aspect of application of electrorheological (ER) and magnetorheological (MR) fluids is the characterization of rheological properties. In this study, two rotational Viscometers to measure the field-dependent flow behavior (shear stress versus shear rate) of ER/MR fluids are theoretically analyzed. One is a rotational coaxial cylinder viscometer, and the other is a rotational parallel disk viscometer. The equations between shear stress and torque as well as shear rate and angular velocity are derived on the basis of the Bingham-plastic, biviscous, and Herschel–Bulkley constitutive models. The shear stress for the rotational coaxial cylinder viscometer can be straightforwardly calculated from the measured torque. However, in order to determine the shear rate, three approximation methods are applied. Meanwhile, the shear stress and shear rate in the rotational parallel disk viscometer can be obtained directly from the torque and angular velocity data. In order to comprehensively understand the flow behavior of ER/MR fluids with respect to the constitutive models, nondimensional analyses are undertaken in this study.
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constitutive models of electrorheological and magnetorheological fluids using Viscometers
Smart Structures and Materials 2003: Damping and Isolation, 2003Co-Authors: Young-tai Choi, Norman M. WereleyAbstract:A key aspect of application of electrorheological (ER) and magnetorheological (MR) fluids is the characterization of rheological properties. For this purpose, two rotational Viscometers are theoretically analyzed. One is a rotational coaxial cylinder viscometer, and the second is a rotational parallel disk viscometer. A key goal is to determine the shear stress and shear rate of ER/MR fluids for both Viscometers from the torque and angular velocity data. To do this, the equations between shear stress and torque as well as shear rate and angular velocity are derived on the basis of the Bingham-plastic, biviscous, and Herschel-Bulkley constitutive models. For simplicity in mathematical form, the Bingham-plastic model is used to describe the flow behavior of ER/MR fluids. The biviscous model characterized by static and dynamic yield stresses is used to capture the preyield behavior. The preyield region where the local shear stress is smaller than the static yield stress has much larger viscosity than the postyield region. In order to account for the shear thinning or thickening in postyield region, the Herschel-Bulkley constitutive model is used in this study. The shear stress for a rotational coaxial cylinder viscometer can be calculated directly from measured torque. However, three approximation methods are applied to determine the shear rate. For rotational parallel disk Viscometers, the shear rate and shear stress can be obtained directly from the torque and angular velocity data. In order to comprehensively understand the flow behavior of ER/MR fluids with respect to the constitutive models, the nondimensional analyses are undertaken in this study.© (2003) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
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Comparative analysis of Bingham characteristics of ER/MR fluids with different Viscometers
Smart Structures and Materials 2002: Damping and Isolation, 2002Co-Authors: Young-tai Choi, Norman M. WereleyAbstract:This paper theoretically presents Bingham characteristics of ER (electrorheological)/MR (magnetorheological) fluids with respect to different rotational Viscometers through comparative analysis. For doing so, two different types of rotational Viscometers are introduced and configured for ER/MR fluids; one is a rotational coaxial cylinder viscometer and the other is a rotational parallel disk viscometer. In order to determine the shear stress and shear rate of fluids tested in both Viscometers, the fundamental equations between shear stress and torque as well as shear rate and angular velocity are derived on the basis of the biviscous constitutive model. The biviscous model is characterized by a yield stress: when the shear stress is less than this yield stress, the preyield viscosity is relatively large compared to the postyield viscosity when shear stress is greater than the yield stress. For rotational coaxial cylinder Viscometers, the shear stress can be calculated directly from the measured torque. However, for the determination of the shear rate, some strategies are required. In this study, different methods of determining the shear rate are developed and their accuracy is assessed. In the case of rotational parallel disk Viscometers, the calculation of the shear rate is straightforward from angular velocity measurements, but the shear stress requires a relatively complicated calculation. In this study, for simplicity, the shear stress is approximated and the error of this approximation is evaluated with respect to important rotational parallel disk viscometer geometry. Finally, the Bingham characteristics of ER/MR fluids at two different rotational Viscometers are theoretically presented and compared in the shear stress vs. shear rate response.
