The Experts below are selected from a list of 261 Experts worldwide ranked by ideXlab platform
Rolf Hut - One of the best experts on this subject based on the ideXlab platform.
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reporting negative results to stimulate Experimental hydrology discussion of the role of Experimental Work in hydrological sciences insights from a community survey
Hydrological Sciences Journal-journal Des Sciences Hydrologiques, 2018Co-Authors: Tim Van Emmerik, Andrea Popp, Anna Solcerova, Hannes Müller, Rolf HutAbstract:ABSTRACTExperimental Work in hydrology is in decline. Based on a community survey, Blume et al. showed that the hydrological community associates Experimental Work with greater risks. One of the main issues with Experimental Work is the higher chance of negative results (defined here as when the expected or wanted result was not observed despite careful Experimental design, planning and execution), resulting in a longer and more difficult publishing process. Reporting on negative results would avoid putting time and resources into repeating experiments that lead to negative results, and give Experimental hydrologists the scientific recognition they deserve. With this commentary, we propose four potential solutions to encourage reporting on negative results, which might contribute to a stimulation of Experimental hydrology.
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Reporting negative results to stimulate Experimental hydrology: discussion of “The role of Experimental Work in hydrological sciences – insights from a community survey”
Hydrological Sciences Journal, 2018Co-Authors: Tim Van Emmerik, Andrea Popp, Anna Solcerova, Hannes Müller, Rolf HutAbstract:ABSTRACTExperimental Work in hydrology is in decline. Based on a community survey, Blume et al. showed that the hydrological community associates Experimental Work with greater risks. One of the main issues with Experimental Work is the higher chance of negative results (defined here as when the expected or wanted result was not observed despite careful Experimental design, planning and execution), resulting in a longer and more difficult publishing process. Reporting on negative results would avoid putting time and resources into repeating experiments that lead to negative results, and give Experimental hydrologists the scientific recognition they deserve. With this commentary, we propose four potential solutions to encourage reporting on negative results, which might contribute to a stimulation of Experimental hydrology.
Hamdy Hassan - One of the best experts on this subject based on the ideXlab platform.
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An Experimental Work on the effect of the eccentric rotation of heat sink on the convective heat transfer
International Journal of Thermal Sciences, 2018Co-Authors: Hamdy Hassan, Souad HarmandAbstract:Abstract The convective heat transfer from air-cooled rotating heat sink helps to estimate the cooling efficiency of the rotating machines cooled by fins. An Experimental Work for the effect of eccentric rotating of the finned heat sink on the convective heat transfer from this heat sink is presented in the Work. The used heat sink is composed of a copper tube with annular fins and its axis of rotation is parallel and offset to the tube axis. The heat sink is heated at the inner surface of the tube with constant heat flux. The Experimental Work is performed at different radiuses of rotation, rotational velocities and powers input to the heat sink. The results illustrate that increasing rotational velocity and radius of rotation decreases the temperature of the heat sink. Nusselt number at the heat sink base decreases with decreasing the radius of rotation and rotational Reynolds number. Nusselt number remains approximately constant through the heat sink length at low rotational velocity. At higher rotational velocity, Nusselt number rises with approaching to the center of the heat sink. Nusselt number increases with increasing the rotating axis length.
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an Experimental Work on the effect of the radius of rotation on the performance of revolving heat pipe rvhp
Applied Thermal Engineering, 2017Co-Authors: Hamdy Hassan, Souad HarmandAbstract:Abstract Rotating heat pipe uses centrifugal acceleration to transfer condensed liquid from the condenser to evaporator. Revolving heat pipe (RVHP) is a rotating heat pipe but its axis of rotation is parallel to and offset from its central axis. This paper presents an Experimental Work on the effect of eccentric rotating of revolving heat pipe on its performance. RVHP used in our Work consists of an evaporator region, an adiabatic region, and a condenser region. It is heated by constant heat flux at the evaporator outer surface and it is cooled by annual fins at the condenser outer surface. The Experimental Work is carried out at different rotational velocities, different radiuses of rotation, and different input powers to the heat pipe. The results show that the temperature of the RVHP increases with decreasing radius of rotation, and rotational velocity and with increasing input power. They also show that, at high rotational velocity, the radius of rotation and rotational velocity haven't a significant effect on the heat pipe temperature. At high rotational velocity, the thermal resistance of the RVHP decreases with increasing the rotational velocity. The radius of rotation has not sensible effect on the maximum Nusselt number of the RVHP of the studied cases at high input power. Increasing Reynolds number increases the Nusselt number on the surface of the heat pipe.
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an Experimental Work on the effect of injection molding parameters on the cavity pressure and product weight
The International Journal of Advanced Manufacturing Technology, 2013Co-Authors: Hamdy HassanAbstract:The injection molding process is one of the most efficient processes where mass production through automation is feasible and products with complex geometry at low cost are easily attained. In this study, an Experimental Work is performed on the effect of injection molding parameters on the polymer pressure inside the mold cavity. Also, the effect of these parameters on the final products' weight is studied. Different process parameters of the injection molding are considered during the Experimental Work (packing pressure, packing time, injection pressure, injection time, and injection temperature). Two polymer materials are used during the Experimental Work (polystyrene (PS) and low-density polyethylene (LDPE)). The mold cavity has a cuboidal form with two different thicknesses. The cavity pressure is measured with time by using pressure Kistler sensor at different injection molding cycles. The results indicate that the cavity pressure and product weight increase with an increase in the packing pressure, packing time, and injection pressure for all the analyzed polymers. They also show that the increase of the filling time decreases the cavity pressure and decreases the product weight in case of PS and LDPE. The results show that the increase of packing pressure by 100 % increases the cavity pressure 50 % in the case of PS and 70 % in the case of LDPE. They also show that the increase of injection pressure by 60 % increases the cavity pressure 36 % in case of PS and 90 % in case of LDPE at an injection temperature of 220 °C. The results indicate that process parameters have an effect on the product weight for LDPE greater than PS. The results obtained specify well the developing of the cavity pressure inside the mold cavity during the injection molding cycles.
Souad Harmand - One of the best experts on this subject based on the ideXlab platform.
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An Experimental Work on the effect of the eccentric rotation of heat sink on the convective heat transfer
International Journal of Thermal Sciences, 2018Co-Authors: Hamdy Hassan, Souad HarmandAbstract:Abstract The convective heat transfer from air-cooled rotating heat sink helps to estimate the cooling efficiency of the rotating machines cooled by fins. An Experimental Work for the effect of eccentric rotating of the finned heat sink on the convective heat transfer from this heat sink is presented in the Work. The used heat sink is composed of a copper tube with annular fins and its axis of rotation is parallel and offset to the tube axis. The heat sink is heated at the inner surface of the tube with constant heat flux. The Experimental Work is performed at different radiuses of rotation, rotational velocities and powers input to the heat sink. The results illustrate that increasing rotational velocity and radius of rotation decreases the temperature of the heat sink. Nusselt number at the heat sink base decreases with decreasing the radius of rotation and rotational Reynolds number. Nusselt number remains approximately constant through the heat sink length at low rotational velocity. At higher rotational velocity, Nusselt number rises with approaching to the center of the heat sink. Nusselt number increases with increasing the rotating axis length.
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an Experimental Work on the effect of the radius of rotation on the performance of revolving heat pipe rvhp
Applied Thermal Engineering, 2017Co-Authors: Hamdy Hassan, Souad HarmandAbstract:Abstract Rotating heat pipe uses centrifugal acceleration to transfer condensed liquid from the condenser to evaporator. Revolving heat pipe (RVHP) is a rotating heat pipe but its axis of rotation is parallel to and offset from its central axis. This paper presents an Experimental Work on the effect of eccentric rotating of revolving heat pipe on its performance. RVHP used in our Work consists of an evaporator region, an adiabatic region, and a condenser region. It is heated by constant heat flux at the evaporator outer surface and it is cooled by annual fins at the condenser outer surface. The Experimental Work is carried out at different rotational velocities, different radiuses of rotation, and different input powers to the heat pipe. The results show that the temperature of the RVHP increases with decreasing radius of rotation, and rotational velocity and with increasing input power. They also show that, at high rotational velocity, the radius of rotation and rotational velocity haven't a significant effect on the heat pipe temperature. At high rotational velocity, the thermal resistance of the RVHP decreases with increasing the rotational velocity. The radius of rotation has not sensible effect on the maximum Nusselt number of the RVHP of the studied cases at high input power. Increasing Reynolds number increases the Nusselt number on the surface of the heat pipe.
Tim Van Emmerik - One of the best experts on this subject based on the ideXlab platform.
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reporting negative results to stimulate Experimental hydrology discussion of the role of Experimental Work in hydrological sciences insights from a community survey
Hydrological Sciences Journal-journal Des Sciences Hydrologiques, 2018Co-Authors: Tim Van Emmerik, Andrea Popp, Anna Solcerova, Hannes Müller, Rolf HutAbstract:ABSTRACTExperimental Work in hydrology is in decline. Based on a community survey, Blume et al. showed that the hydrological community associates Experimental Work with greater risks. One of the main issues with Experimental Work is the higher chance of negative results (defined here as when the expected or wanted result was not observed despite careful Experimental design, planning and execution), resulting in a longer and more difficult publishing process. Reporting on negative results would avoid putting time and resources into repeating experiments that lead to negative results, and give Experimental hydrologists the scientific recognition they deserve. With this commentary, we propose four potential solutions to encourage reporting on negative results, which might contribute to a stimulation of Experimental hydrology.
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Reporting negative results to stimulate Experimental hydrology: discussion of “The role of Experimental Work in hydrological sciences – insights from a community survey”
Hydrological Sciences Journal, 2018Co-Authors: Tim Van Emmerik, Andrea Popp, Anna Solcerova, Hannes Müller, Rolf HutAbstract:ABSTRACTExperimental Work in hydrology is in decline. Based on a community survey, Blume et al. showed that the hydrological community associates Experimental Work with greater risks. One of the main issues with Experimental Work is the higher chance of negative results (defined here as when the expected or wanted result was not observed despite careful Experimental design, planning and execution), resulting in a longer and more difficult publishing process. Reporting on negative results would avoid putting time and resources into repeating experiments that lead to negative results, and give Experimental hydrologists the scientific recognition they deserve. With this commentary, we propose four potential solutions to encourage reporting on negative results, which might contribute to a stimulation of Experimental hydrology.
Barbara Japelj Pavešić - One of the best experts on this subject based on the ideXlab platform.
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Science achievement, gender differences, and Experimental Work in classes in Slovenia as evident in TIMSS studies
Studies in Educational Evaluation, 2008Co-Authors: Barbara Japelj PavešićAbstract:Abstract Since 1999, Slovenia has been in the process of introducing nine years of compulsory education to replace the previous eight-year system of compulsory education. Under the new system, the school entry age is six years rather than the former seven years. This reform of the system necessitated a number of other changes, such as those relating to the curriculum and teaching approaches. The purpose of this study was to compare the “new” Slovenian science curriculum with the “old” to ascertain if different relationships exist between the two in terms of achievement and gender, attitudes toward science, and the amount of Experimental Work undertaken by students in school. Data from the IEA TIMSS 2003 study were used to analyze these relationships. The analyses employed basic statistics and log-linear modeling of the effects of gender, school system, amount of Experimental Work in school, and students’ science achievement. Compared to students taught under the old curriculum, students taught under the new curriculum performed slightly better on the overall science test. A large decrease in gender differences in achievement was also apparent. The relationship between Experimental Work and achievement strengthened. Conducting experiments at every lesson related to lower student achievement, while conducting experiments during half of the science lessons related to higher achievement. These findings have a clear message for teachers and policymakers. A moderate amount of time devoted to student Experimental Work seems to raise science achievement of students as well as promote more positive attitudes toward learning science.
