The Experts below are selected from a list of 98418 Experts worldwide ranked by ideXlab platform
P Gaehtgens - One of the best experts on this subject based on the ideXlab platform.
-
blood viscosity in tube Flow Dependence on diameter and hematocrit
American Journal of Physiology-heart and Circulatory Physiology, 1992Co-Authors: Axel R Pries, David Neuhaus, P GaehtgensAbstract:Since the original publications by Martini et al. (Dtsch. Arch. Klin. Med. 169: 212–222, 1930) and Fahraeus and Lindqvist (Am. J. Physiol. 96: 562–568, 1931), it has been known that the relative ap...
-
Blood viscosity in tube Flow: Dependence on diameter and hematocrit
American Journal of Physiology-Heart and Circulatory Physiology, 1992Co-Authors: Axel R Pries, David Neuhaus, P GaehtgensAbstract:Since the original publications by Martini et al. (Dtsch. Arch. Klin. Med. 169: 212-222, 1930) and Fahraeus and Lindqvist (Am. J. Physiol. 96: 562-568, 1931), it has been known that the relative apparent viscosity of blood in tube Flow depends on tube diameter. Quantitative descriptions of this effect and of the Dependence of blood viscosity on hematocrit in the different diameter tubes are required for the development of hydrodynamic models of blood Flow through the microcirculation. The present study provides a comprehensive data base for the description of relative apparent blood viscosity as a function of tube diameter and hematocrit. Data available from the literature are compiled, and new experimental data obtained in a capillary viscometer are presented. The combined data base comprises measurements at high shear rates (u > or = 50 s-1) in tubes with diameters ranging from 3.3 to 1,978 microns at hematocrits of up to 0.9. If corrected for differences in suspending medium viscosity and temperature, the data show remarkable agreement. Empirical fitting equations predicting relative apparent blood viscosity from tube diameter and hematocrit are presented. A pronounced change in the hematocrit Dependence of relative viscosity is observed in a range of tube diameters in which viscosity is minimal. While a linear hematocrit-viscosity relationship is found in tubes of < or = 6 microns, an overproportional increase of viscosity with hematocrit prevails in tubes of > or = 9 microns. This is interpreted to reflect the hematocrit-dependent transition from single- to multifile arrangement of cells in Flow.
Axel R Pries - One of the best experts on this subject based on the ideXlab platform.
-
blood viscosity in tube Flow Dependence on diameter and hematocrit
American Journal of Physiology-heart and Circulatory Physiology, 1992Co-Authors: Axel R Pries, David Neuhaus, P GaehtgensAbstract:Since the original publications by Martini et al. (Dtsch. Arch. Klin. Med. 169: 212–222, 1930) and Fahraeus and Lindqvist (Am. J. Physiol. 96: 562–568, 1931), it has been known that the relative ap...
-
Blood viscosity in tube Flow: Dependence on diameter and hematocrit
American Journal of Physiology-Heart and Circulatory Physiology, 1992Co-Authors: Axel R Pries, David Neuhaus, P GaehtgensAbstract:Since the original publications by Martini et al. (Dtsch. Arch. Klin. Med. 169: 212-222, 1930) and Fahraeus and Lindqvist (Am. J. Physiol. 96: 562-568, 1931), it has been known that the relative apparent viscosity of blood in tube Flow depends on tube diameter. Quantitative descriptions of this effect and of the Dependence of blood viscosity on hematocrit in the different diameter tubes are required for the development of hydrodynamic models of blood Flow through the microcirculation. The present study provides a comprehensive data base for the description of relative apparent blood viscosity as a function of tube diameter and hematocrit. Data available from the literature are compiled, and new experimental data obtained in a capillary viscometer are presented. The combined data base comprises measurements at high shear rates (u > or = 50 s-1) in tubes with diameters ranging from 3.3 to 1,978 microns at hematocrits of up to 0.9. If corrected for differences in suspending medium viscosity and temperature, the data show remarkable agreement. Empirical fitting equations predicting relative apparent blood viscosity from tube diameter and hematocrit are presented. A pronounced change in the hematocrit Dependence of relative viscosity is observed in a range of tube diameters in which viscosity is minimal. While a linear hematocrit-viscosity relationship is found in tubes of < or = 6 microns, an overproportional increase of viscosity with hematocrit prevails in tubes of > or = 9 microns. This is interpreted to reflect the hematocrit-dependent transition from single- to multifile arrangement of cells in Flow.
David Neuhaus - One of the best experts on this subject based on the ideXlab platform.
-
blood viscosity in tube Flow Dependence on diameter and hematocrit
American Journal of Physiology-heart and Circulatory Physiology, 1992Co-Authors: Axel R Pries, David Neuhaus, P GaehtgensAbstract:Since the original publications by Martini et al. (Dtsch. Arch. Klin. Med. 169: 212–222, 1930) and Fahraeus and Lindqvist (Am. J. Physiol. 96: 562–568, 1931), it has been known that the relative ap...
-
Blood viscosity in tube Flow: Dependence on diameter and hematocrit
American Journal of Physiology-Heart and Circulatory Physiology, 1992Co-Authors: Axel R Pries, David Neuhaus, P GaehtgensAbstract:Since the original publications by Martini et al. (Dtsch. Arch. Klin. Med. 169: 212-222, 1930) and Fahraeus and Lindqvist (Am. J. Physiol. 96: 562-568, 1931), it has been known that the relative apparent viscosity of blood in tube Flow depends on tube diameter. Quantitative descriptions of this effect and of the Dependence of blood viscosity on hematocrit in the different diameter tubes are required for the development of hydrodynamic models of blood Flow through the microcirculation. The present study provides a comprehensive data base for the description of relative apparent blood viscosity as a function of tube diameter and hematocrit. Data available from the literature are compiled, and new experimental data obtained in a capillary viscometer are presented. The combined data base comprises measurements at high shear rates (u > or = 50 s-1) in tubes with diameters ranging from 3.3 to 1,978 microns at hematocrits of up to 0.9. If corrected for differences in suspending medium viscosity and temperature, the data show remarkable agreement. Empirical fitting equations predicting relative apparent blood viscosity from tube diameter and hematocrit are presented. A pronounced change in the hematocrit Dependence of relative viscosity is observed in a range of tube diameters in which viscosity is minimal. While a linear hematocrit-viscosity relationship is found in tubes of < or = 6 microns, an overproportional increase of viscosity with hematocrit prevails in tubes of > or = 9 microns. This is interpreted to reflect the hematocrit-dependent transition from single- to multifile arrangement of cells in Flow.
John W. Hunt - One of the best experts on this subject based on the ideXlab platform.
-
An investigation of the Flow Dependence of temperature gradients near large vessels during steady state and transient tissue heating
Physics in medicine and biology, 1999Co-Authors: Michael C. Kolios, Arthur E. Worthington, David W. Holdsworth, Michael D. Sherar, John W. HuntAbstract:Temperature distributions measured during thermal therapy are a major prognostic factor of the efficacy and success of the procedure. Thermal models are used to predict the temperature elevation of tissues during heating. Theoretical work has shown that blood Flow through large blood vessels plays an important role in determining temperature profiles of heated tissues. In this paper, an experimental investigation of the effects of large vessels on the temperature distribution of heated tissue is performed. The blood Flow Dependence of steady state and transient temperature profiles created by a cylindrical conductive heat source and an ultrasound transducer were examined using a fixed porcine kidney as a Flow model. In the transient experiments, a 20 s pulse of hot water, 30 degrees C above ambient, heated the tissues. Temperatures were measured at selected locations in steps of 0.1 mm. It was observed that vessels could either heat or cool tissues depending on the orientation of the vascular geometry with respect to the heat source and that these effects are a function of Flow rate through the vessels. Temperature gradients of 6 degrees C mm(-1) close to large vessels were routinely measured. Furthermore, it was observed that the temperature gradients caused by large vessels depended on whether the heating source was highly localized (i.e. a hot needle) or more distributed (i.e. external ultrasound). The gradients measured near large vessels during localized heating were between two and three times greater than the gradients measured during ultrasound heating at the same location, for comparable Flows. Moreover, these gradients were more sensitive to Flow variations for the localized needle heating. X-ray computed tomography data of the kidney vasculature were in good spatial agreement with the locations of all of the temperature variations measured. The three dimensional vessel path observed could account for the complex features of the temperature profiles. The Flow Dependences of the transient temperature profiles near large vessels during the pulsed experiments were consistent with the temperature distributions measured in the steady state experiments and provided unique insights into the process of convective heat transfer in tissues. Finally, it was shown that even for very short treatment times (3-20 s), large vessels had significant effects on the tissue temperature distributions.
Sam Jin Jeong - One of the best experts on this subject based on the ideXlab platform.
-
improving parallelism of nested loops with non uniform Dependences
Network and Parallel Computing, 2005Co-Authors: Sam Jin JeongAbstract:This paper defines the properties of FDT (Flow Dependence Tail set) and FDH (Flow Dependence Head set), and presents two partitioning methods for finding two parallel regions in two-dimensional solution space. One is the region partitioning method by intersection of FDT and FDH. Another is the region partitioning method by two given equations. Both methods show how to determine whether the intersection of FDT and FDH is empty or not. In the case that FDT does not overlap FDH, we will divide the iteration space into two parallel regions by a line. The iterations within each area can be fully executed in parallel. So, we can find two parallel regions for doubly nested loops with non-uniform Dependences for maximizing parallelism.
-
APPT - A loop transformation using two parallel region partitioning method
Lecture Notes in Computer Science, 2005Co-Authors: Sam Jin Jeong, Jung Soo HanAbstract:Loop parallelization is an important optimization issue in the execution of scientific programs. This paper proposes loop transformation techniques for finding parallel regions within nested loops with non-uniform Dependences in order to improve parallelism. By parallelizing anti Dependence region using variable renaming, there remains only Flow Dependence in the loop. We then divide the iteration space into FDT (Flow Dependence Tail set) and FDH (Flow Dependence Head set). By two given equations, we show how to determine whether the intersection of FDT and FDH is empty or not. So, we can find two parallel regions for doubly nested loops with non-uniform Dependences. In the case that FDT does not overlap FDH, we will divide the iteration space into two parallel regions by a line.
-
ICESS - Maximizing parallelism for non-uniform Dependence loops using two parallel region partitioning method
Embedded Software and Systems, 2005Co-Authors: Sam Jin JeongAbstract:The existing parallelizing compilers can parallelize most of the loops with uniform Dependences, but they do not satisfactorily handle loops with non-uniform Dependences. Most of the time, the compiler leaves such loops running sequentially. Unfortunately, loops with non-uniform Dependences are not so uncommon in the real world. This paper presents the two parallel region partitioning method of nested loops with non-uniform Dependences for maximizing parallelism. By parallelizing anti Dependence region using variable re-naming, we will divide the iteration space into two parallel regions by a line in case that FDT (Flow Dependence Tail set) does not overlap FDH (Flow Dependence Head set). Comparison with some related works shows more parallelism than other existing methods.
-
NPC - Improving parallelism of nested loops with non-uniform Dependences
Lecture Notes in Computer Science, 2005Co-Authors: Sam Jin Jeong, Kun Hee HanAbstract:This paper defines the properties of FDT (Flow Dependence Tail set) and FDH (Flow Dependence Head set), and presents two partitioning methods for finding two parallel regions in two-dimensional solution space. One is the region partitioning method by intersection of FDT and FDH. Another is the region partitioning method by two given equations. Both methods show how to determine whether the intersection of FDT and FDH is empty or not. In the case that FDT does not overlap FDH, we will divide the iteration space into two parallel regions by a line. The iterations within each area can be fully executed in parallel. So, we can find two parallel regions for doubly nested loops with non-uniform Dependences for maximizing parallelism.