The Experts below are selected from a list of 288 Experts worldwide ranked by ideXlab platform
Robert O Teskey - One of the best experts on this subject based on the ideXlab platform.
-
a comparison of sap flux density using thermal dissipation heat Pulse Velocity and heat field deformation methods
Agricultural and Forest Meteorology, 2010Co-Authors: Kathy Steppe, Tanya M. Doody, Dirk J. W. De Pauw, Robert O TeskeyAbstract:Abstract A laboratory test and field evaluation were conducted to determine the accuracy of the three commonly used techniques for measuring sap flux density in trees: heat Pulse Velocity, thermal dissipation and heat field deformation. In the laboratory test a constant flow rate of water was maintained through freshly cut stem segments of diffuse-porous Fagus grandifolia trees with mean sapwood depths of 4.02 ± 0.14 and 7.44 ± 0.51 cm for sample trees with stem diameter at breast height of 15 and 21 cm, respectively. The three sensor types were measured simultaneously and compared against gravimetric measurements. All three techniques substantially underestimated sap flux density. On average the actual sap flux density was underestimated by 35% using heat Pulse Velocity (with wound correction), 46% using heat field deformation and 60% using thermal dissipation. These results were consistent across sap flux densities ranging from 5 to 80 cm3 cm−2 h−1. Heat Pulse Velocity measurements were more variable than those of the other two techniques, and the least accurate at low sap flux densities. An error analysis was conducted on all parameters of the equations used with each technique. That analysis indicated that each technique has unique sensitivities to errors in parameter estimates which need to be taken into consideration. Except for the use of heat, the three techniques are quite different and there appeared to be no single reason why the methods underestimated actual sap flux density, but rather there were likely multiple errors that compounded to reduce the overall accuracy of each technique. Field measurements supported the relative sensor performance observed in the laboratory. Applying a sensor-specific correction factor based on the laboratory test to the field data produced similar estimates of sap flux density from all three techniques. We conclude that a species-specific calibration is necessary when using any of these techniques to insure that accurate estimates of sap flux density are obtained, at least until a physical basis for an error correction can be proposed.
-
A comparison of sap flux density using thermal dissipation, heat Pulse Velocity and heat field deformation methods
Agricultural and Forest Meteorology, 2010Co-Authors: Kathy Steppe, Tanya M. Doody, Dirk J. W. De Pauw, Robert O TeskeyAbstract:A laboratory test and field evaluation were conducted to determine the accuracy of the three commonly used techniques for measuring sap flux density in trees: heat Pulse Velocity, thermal dissipation and heat field deformation. In the laboratory test a constant flow rate of water was maintained through freshly cut stem segments of diffuse-porous Fagus grandifolia trees with mean sapwood depths of 4.02??0.14 and 7.44??0.51cm for sample trees with stem diameter at breast height of 15 and 21cm, respectively. The three sensor types were measured simultaneously and compared against gravimetric measurements. All three techniques substantially underestimated sap flux density. On average the actual sap flux density was underestimated by 35% using heat Pulse Velocity (with wound correction), 46% using heat field deformation and 60% using thermal dissipation. These results were consistent across sap flux densities ranging from 5 to 80cm3cm-2h-1. Heat Pulse Velocity measurements were more variable than those of the other two techniques, and the least accurate at low sap flux densities. An error analysis was conducted on all parameters of the equations used with each technique. That analysis indicated that each technique has unique sensitivities to errors in parameter estimates which need to be taken into consideration. Except for the use of heat, the three techniques are quite different and there appeared to be no single reason why the methods underestimated actual sap flux density, but rather there were likely multiple errors that compounded to reduce the overall accuracy of each technique. Field measurements supported the relative sensor performance observed in the laboratory. Applying a sensor-specific correction factor based on the laboratory test to the field data produced similar estimates of sap flux density from all three techniques. We conclude that a species-specific calibration is necessary when using any of these techniques to insure that accurate estimates of sap flux density are obtained, at least until a physical basis for an error correction can be proposed. ?? 2010 Elsevier B.V.
Kathy Steppe - One of the best experts on this subject based on the ideXlab platform.
-
a comparison of sap flux density using thermal dissipation heat Pulse Velocity and heat field deformation methods
Agricultural and Forest Meteorology, 2010Co-Authors: Kathy Steppe, Tanya M. Doody, Dirk J. W. De Pauw, Robert O TeskeyAbstract:Abstract A laboratory test and field evaluation were conducted to determine the accuracy of the three commonly used techniques for measuring sap flux density in trees: heat Pulse Velocity, thermal dissipation and heat field deformation. In the laboratory test a constant flow rate of water was maintained through freshly cut stem segments of diffuse-porous Fagus grandifolia trees with mean sapwood depths of 4.02 ± 0.14 and 7.44 ± 0.51 cm for sample trees with stem diameter at breast height of 15 and 21 cm, respectively. The three sensor types were measured simultaneously and compared against gravimetric measurements. All three techniques substantially underestimated sap flux density. On average the actual sap flux density was underestimated by 35% using heat Pulse Velocity (with wound correction), 46% using heat field deformation and 60% using thermal dissipation. These results were consistent across sap flux densities ranging from 5 to 80 cm3 cm−2 h−1. Heat Pulse Velocity measurements were more variable than those of the other two techniques, and the least accurate at low sap flux densities. An error analysis was conducted on all parameters of the equations used with each technique. That analysis indicated that each technique has unique sensitivities to errors in parameter estimates which need to be taken into consideration. Except for the use of heat, the three techniques are quite different and there appeared to be no single reason why the methods underestimated actual sap flux density, but rather there were likely multiple errors that compounded to reduce the overall accuracy of each technique. Field measurements supported the relative sensor performance observed in the laboratory. Applying a sensor-specific correction factor based on the laboratory test to the field data produced similar estimates of sap flux density from all three techniques. We conclude that a species-specific calibration is necessary when using any of these techniques to insure that accurate estimates of sap flux density are obtained, at least until a physical basis for an error correction can be proposed.
-
A comparison of sap flux density using thermal dissipation, heat Pulse Velocity and heat field deformation methods
Agricultural and Forest Meteorology, 2010Co-Authors: Kathy Steppe, Tanya M. Doody, Dirk J. W. De Pauw, Robert O TeskeyAbstract:A laboratory test and field evaluation were conducted to determine the accuracy of the three commonly used techniques for measuring sap flux density in trees: heat Pulse Velocity, thermal dissipation and heat field deformation. In the laboratory test a constant flow rate of water was maintained through freshly cut stem segments of diffuse-porous Fagus grandifolia trees with mean sapwood depths of 4.02??0.14 and 7.44??0.51cm for sample trees with stem diameter at breast height of 15 and 21cm, respectively. The three sensor types were measured simultaneously and compared against gravimetric measurements. All three techniques substantially underestimated sap flux density. On average the actual sap flux density was underestimated by 35% using heat Pulse Velocity (with wound correction), 46% using heat field deformation and 60% using thermal dissipation. These results were consistent across sap flux densities ranging from 5 to 80cm3cm-2h-1. Heat Pulse Velocity measurements were more variable than those of the other two techniques, and the least accurate at low sap flux densities. An error analysis was conducted on all parameters of the equations used with each technique. That analysis indicated that each technique has unique sensitivities to errors in parameter estimates which need to be taken into consideration. Except for the use of heat, the three techniques are quite different and there appeared to be no single reason why the methods underestimated actual sap flux density, but rather there were likely multiple errors that compounded to reduce the overall accuracy of each technique. Field measurements supported the relative sensor performance observed in the laboratory. Applying a sensor-specific correction factor based on the laboratory test to the field data produced similar estimates of sap flux density from all three techniques. We conclude that a species-specific calibration is necessary when using any of these techniques to insure that accurate estimates of sap flux density are obtained, at least until a physical basis for an error correction can be proposed. ?? 2010 Elsevier B.V.
Tanya M. Doody - One of the best experts on this subject based on the ideXlab platform.
-
a comparison of sap flux density using thermal dissipation heat Pulse Velocity and heat field deformation methods
Agricultural and Forest Meteorology, 2010Co-Authors: Kathy Steppe, Tanya M. Doody, Dirk J. W. De Pauw, Robert O TeskeyAbstract:Abstract A laboratory test and field evaluation were conducted to determine the accuracy of the three commonly used techniques for measuring sap flux density in trees: heat Pulse Velocity, thermal dissipation and heat field deformation. In the laboratory test a constant flow rate of water was maintained through freshly cut stem segments of diffuse-porous Fagus grandifolia trees with mean sapwood depths of 4.02 ± 0.14 and 7.44 ± 0.51 cm for sample trees with stem diameter at breast height of 15 and 21 cm, respectively. The three sensor types were measured simultaneously and compared against gravimetric measurements. All three techniques substantially underestimated sap flux density. On average the actual sap flux density was underestimated by 35% using heat Pulse Velocity (with wound correction), 46% using heat field deformation and 60% using thermal dissipation. These results were consistent across sap flux densities ranging from 5 to 80 cm3 cm−2 h−1. Heat Pulse Velocity measurements were more variable than those of the other two techniques, and the least accurate at low sap flux densities. An error analysis was conducted on all parameters of the equations used with each technique. That analysis indicated that each technique has unique sensitivities to errors in parameter estimates which need to be taken into consideration. Except for the use of heat, the three techniques are quite different and there appeared to be no single reason why the methods underestimated actual sap flux density, but rather there were likely multiple errors that compounded to reduce the overall accuracy of each technique. Field measurements supported the relative sensor performance observed in the laboratory. Applying a sensor-specific correction factor based on the laboratory test to the field data produced similar estimates of sap flux density from all three techniques. We conclude that a species-specific calibration is necessary when using any of these techniques to insure that accurate estimates of sap flux density are obtained, at least until a physical basis for an error correction can be proposed.
-
A comparison of sap flux density using thermal dissipation, heat Pulse Velocity and heat field deformation methods
Agricultural and Forest Meteorology, 2010Co-Authors: Kathy Steppe, Tanya M. Doody, Dirk J. W. De Pauw, Robert O TeskeyAbstract:A laboratory test and field evaluation were conducted to determine the accuracy of the three commonly used techniques for measuring sap flux density in trees: heat Pulse Velocity, thermal dissipation and heat field deformation. In the laboratory test a constant flow rate of water was maintained through freshly cut stem segments of diffuse-porous Fagus grandifolia trees with mean sapwood depths of 4.02??0.14 and 7.44??0.51cm for sample trees with stem diameter at breast height of 15 and 21cm, respectively. The three sensor types were measured simultaneously and compared against gravimetric measurements. All three techniques substantially underestimated sap flux density. On average the actual sap flux density was underestimated by 35% using heat Pulse Velocity (with wound correction), 46% using heat field deformation and 60% using thermal dissipation. These results were consistent across sap flux densities ranging from 5 to 80cm3cm-2h-1. Heat Pulse Velocity measurements were more variable than those of the other two techniques, and the least accurate at low sap flux densities. An error analysis was conducted on all parameters of the equations used with each technique. That analysis indicated that each technique has unique sensitivities to errors in parameter estimates which need to be taken into consideration. Except for the use of heat, the three techniques are quite different and there appeared to be no single reason why the methods underestimated actual sap flux density, but rather there were likely multiple errors that compounded to reduce the overall accuracy of each technique. Field measurements supported the relative sensor performance observed in the laboratory. Applying a sensor-specific correction factor based on the laboratory test to the field data produced similar estimates of sap flux density from all three techniques. We conclude that a species-specific calibration is necessary when using any of these techniques to insure that accurate estimates of sap flux density are obtained, at least until a physical basis for an error correction can be proposed. ?? 2010 Elsevier B.V.
Dirk J. W. De Pauw - One of the best experts on this subject based on the ideXlab platform.
-
a comparison of sap flux density using thermal dissipation heat Pulse Velocity and heat field deformation methods
Agricultural and Forest Meteorology, 2010Co-Authors: Kathy Steppe, Tanya M. Doody, Dirk J. W. De Pauw, Robert O TeskeyAbstract:Abstract A laboratory test and field evaluation were conducted to determine the accuracy of the three commonly used techniques for measuring sap flux density in trees: heat Pulse Velocity, thermal dissipation and heat field deformation. In the laboratory test a constant flow rate of water was maintained through freshly cut stem segments of diffuse-porous Fagus grandifolia trees with mean sapwood depths of 4.02 ± 0.14 and 7.44 ± 0.51 cm for sample trees with stem diameter at breast height of 15 and 21 cm, respectively. The three sensor types were measured simultaneously and compared against gravimetric measurements. All three techniques substantially underestimated sap flux density. On average the actual sap flux density was underestimated by 35% using heat Pulse Velocity (with wound correction), 46% using heat field deformation and 60% using thermal dissipation. These results were consistent across sap flux densities ranging from 5 to 80 cm3 cm−2 h−1. Heat Pulse Velocity measurements were more variable than those of the other two techniques, and the least accurate at low sap flux densities. An error analysis was conducted on all parameters of the equations used with each technique. That analysis indicated that each technique has unique sensitivities to errors in parameter estimates which need to be taken into consideration. Except for the use of heat, the three techniques are quite different and there appeared to be no single reason why the methods underestimated actual sap flux density, but rather there were likely multiple errors that compounded to reduce the overall accuracy of each technique. Field measurements supported the relative sensor performance observed in the laboratory. Applying a sensor-specific correction factor based on the laboratory test to the field data produced similar estimates of sap flux density from all three techniques. We conclude that a species-specific calibration is necessary when using any of these techniques to insure that accurate estimates of sap flux density are obtained, at least until a physical basis for an error correction can be proposed.
-
A comparison of sap flux density using thermal dissipation, heat Pulse Velocity and heat field deformation methods
Agricultural and Forest Meteorology, 2010Co-Authors: Kathy Steppe, Tanya M. Doody, Dirk J. W. De Pauw, Robert O TeskeyAbstract:A laboratory test and field evaluation were conducted to determine the accuracy of the three commonly used techniques for measuring sap flux density in trees: heat Pulse Velocity, thermal dissipation and heat field deformation. In the laboratory test a constant flow rate of water was maintained through freshly cut stem segments of diffuse-porous Fagus grandifolia trees with mean sapwood depths of 4.02??0.14 and 7.44??0.51cm for sample trees with stem diameter at breast height of 15 and 21cm, respectively. The three sensor types were measured simultaneously and compared against gravimetric measurements. All three techniques substantially underestimated sap flux density. On average the actual sap flux density was underestimated by 35% using heat Pulse Velocity (with wound correction), 46% using heat field deformation and 60% using thermal dissipation. These results were consistent across sap flux densities ranging from 5 to 80cm3cm-2h-1. Heat Pulse Velocity measurements were more variable than those of the other two techniques, and the least accurate at low sap flux densities. An error analysis was conducted on all parameters of the equations used with each technique. That analysis indicated that each technique has unique sensitivities to errors in parameter estimates which need to be taken into consideration. Except for the use of heat, the three techniques are quite different and there appeared to be no single reason why the methods underestimated actual sap flux density, but rather there were likely multiple errors that compounded to reduce the overall accuracy of each technique. Field measurements supported the relative sensor performance observed in the laboratory. Applying a sensor-specific correction factor based on the laboratory test to the field data produced similar estimates of sap flux density from all three techniques. We conclude that a species-specific calibration is necessary when using any of these techniques to insure that accurate estimates of sap flux density are obtained, at least until a physical basis for an error correction can be proposed. ?? 2010 Elsevier B.V.
Konstantin Kovler - One of the best experts on this subject based on the ideXlab platform.
-
Correction to: Application of ultrasonic Pulse Velocity for assessment of thermal expansion coefficient of concrete at early age
Materials and Structures, 2019Co-Authors: Semion Zhutovsky, Konstantin KovlerAbstract:The article Application of ultrasonic Pulse Velocity for assessment of thermal expansion coefficient of concrete at early age, written by Semion Zhutovsky, Konstantin Kovler, was originally published Online without Open Access.
-
Application of ultrasonic Pulse Velocity for assessment of thermal expansion coefficient of concrete at early age
Materials and Structures, 2016Co-Authors: Semion Zhutovsky, Konstantin KovlerAbstract:Early age deformations, in concrete, may lead to cracking reducing its mechanical properties and service live. Cracking risk analysis is an essential part of a concrete design, and coefficient of thermal expansion of concrete is indispensable for this purpose. In this paper, an approach that utilizes ultrasonic Pulse Velocity measurements for assessment of thermal expansion coefficient of concrete at the early age is proposed. An expression for the calculation of the coefficient of thermal expansion was derived based on the theory of poromechanics. Free shrinkage and ultrasonic Pulse Velocity of cement paste with water to cement ratio of 0.33 were measured starting from the casting, in order to validate the formula. The calculated values were in an agreement with the data found in the literature, though the effect of self-desiccation was not captured. In addition, the calculated value of thermal expansion coefficient was used for decoupling of autogenous and thermal shrinkage of cement paste. Decoupled linear autogenous shrinkage was compared to the autogenous shrinkage measured by volumetric method.
