In recent years,water collecting systems,with the associated advantages of energy saving and noise reduction,have become the foundation for the development of a scheme to optimize the structure of cooling towers.To ex...In recent years,water collecting systems,with the associated advantages of energy saving and noise reduction,have become the foundation for the development of a scheme to optimize the structure of cooling towers.To explore the feasibility of this approach for mechanical draft cooling towers,a small-scale experimental device has been built to study the resistance and splash performances of three U-type water collecting devices(WCDs)for different water flow rates and wind speeds.The experimental results show that within the considered ranges of wind speed and water flow rate,the pressure drop of the different WCDs can vary significantly.The resistance and local splash performances can also be remarkably different.Some recommendations about the most suitable system are provided.Moreover,a regression analysis of the experimental data is conducted,and the resulting fitting formulas for resistance and splash performance of WCD are reported.展开更多
In this paper,the fow physics and impact dynamics of a sphere bouncing on a water surface are studied experimentally.During the experiments,high-speed camera photography techniques are used to capture the cavity and f...In this paper,the fow physics and impact dynamics of a sphere bouncing on a water surface are studied experimentally.During the experiments,high-speed camera photography techniques are used to capture the cavity and free surface evolution when the sphere impacts and skips on the water surface.The infuences of the impact velocity(v_(1))and impact angle(θ_(1))of the sphere on the bouncing fow physics are also investigated,including the cavitation evolution,motion characteristics,and bounding law.Regulations for the relationship between v_(1)andθ_(1)to judge whether the sphere can bounce on the water surface are presented and analyzed by summarizing a large amount of experimental data.In addition,the efect ofθ_(1)on the energy loss of the sphere is also analyzed and discussed.The experiment results show that there is a ftted curve of v_(1)=17.5θ_(1)−45.5 determining the relationship between the critical initial velocity and angle whether the sphere bounces on the water surface.展开更多
There is some discussion as to whether exercise-induced hyperthermia of the superficial digital flexor tendon (SDFT) affects tenocyte viability and pre-disposes to injury. Cold-therapy is commonly used as a preventati...There is some discussion as to whether exercise-induced hyperthermia of the superficial digital flexor tendon (SDFT) affects tenocyte viability and pre-disposes to injury. Cold-therapy is commonly used as a preventative measure and treatment for acute tendon injuries, but only a few studies have evaluated the effect of cold-therapy on metacarpal temperatures in the horse. For this reason, this study has measured skin surface temperatures after moderate exercise and after application of cold-therapy, and additionally monitored the duration of any effects. Four horses were recruited into a semi blinded controlled study with repeated measurements that involved lunged exercise for 16 minutes at moderate intensity. Skin surface temperature was measured using a thermographic camera before and after lunging, and every 40 minutes for two hours post cold-therapy. Cold-therapy was applied using a Jacks Whirlpool Boot with ice-water immersion at a level just distal to the carpus for 20 minutes. The right leg was treated, and the left leg was used as an untreated control. The experiment was conducted twice on all four horses. Moderate exercise resulted in an increase in skin surface temperature of 10<sup>°</sup>C. Application of cold-therapy for 20 minutes resulted in a reduction in skin surface temperature by 14<sup>°</sup>C. The effect of cold-therapy persisted for at least 40 minutes post treatment. It is concluded that exercise leads to an increase in skin surface temperature which is counteracted by the application of cold-therapy. These findings would seem to indicate that cold-therapy can be used after exercise to counteract hyperthermia within the metacarpal region of the horse’s leg.展开更多
Water activity-temperature relationships are reported for Yukon soil-isolated strains of Mortierella alpina and Penicillium expansum that are natural enemies to larvae(infestation stage)of the winter tick Dermacentor ...Water activity-temperature relationships are reported for Yukon soil-isolated strains of Mortierella alpina and Penicillium expansum that are natural enemies to larvae(infestation stage)of the winter tick Dermacentor albipictus.Both fungal strains are psychrotrophs,characterized by low thermal growth ranges,consistent with their occurrence in Yukon soil.In contrast to P.expansum,M.alpina is more temperature sensitive,has a higher requirement,and is more virulent to tick larvae.Researchers and Biological Control Officers should note that for tick population control these M.alpina and P.expansum strains grow and sporulate well under moderate temperature and humid conditions.Our experiments used Met52®Bioinsecticide as a positive control,and this is the first study that demonstrates the effectiveness of this commercial product against winter tick larvae.展开更多
The effects of lance height and bottom blown flowrate on the mixed time, the splashing amount, the penetrating depth, and the level fluctuation of an 85 t combined blown converter have been studied using a water model...The effects of lance height and bottom blown flowrate on the mixed time, the splashing amount, the penetrating depth, and the level fluctuation of an 85 t combined blown converter have been studied using a water model. The results show that the maximal stirring energy is provided to the bath at the top lance height of about 50-100 mm. When the top lance height is in the range ofg0- 110 mm, the splashing amount caused by the top jet can reach the maximal value. The appropriate operational parameters of Chongqing Iron and Steel Company （CISC） converter have been established that the top lance height is 1600-1760 mm and the bottom blowing flowrate is 240-480 Nm^3/h in the primary phase of a heat, 1100-1300 mm and 160-200 Nm^3/h in the second phase, and 1040-1120 mm and 200-350 Nm^3/h in the end phase. Also, the trial shows that the metallurgical result of the studied blow pattern is better than that of the former pattern. At the starting 3-4 min of a heat, the strong splashing is eliminated. 2008 University of Science and Technology Beijing. All rights reserved.展开更多
基金This work was supported by the Shandong Natural Science Foundation(Grant No.ZR2022ME008)the Shenzhen Science and Technology Program(KCXFZ20201221173409026)+2 种基金the Young Scholars Program of Shandong University(YSPSDU,No.2018WLJH73)the Open Project of State Key Laboratory of Clean Energy Utilization,Zhejiang University(Program No.ZJUCEU2020011)the Shandong Natural Science Foundation(Grant No.ZR2021ME118).
文摘In recent years,water collecting systems,with the associated advantages of energy saving and noise reduction,have become the foundation for the development of a scheme to optimize the structure of cooling towers.To explore the feasibility of this approach for mechanical draft cooling towers,a small-scale experimental device has been built to study the resistance and splash performances of three U-type water collecting devices(WCDs)for different water flow rates and wind speeds.The experimental results show that within the considered ranges of wind speed and water flow rate,the pressure drop of the different WCDs can vary significantly.The resistance and local splash performances can also be remarkably different.Some recommendations about the most suitable system are provided.Moreover,a regression analysis of the experimental data is conducted,and the resulting fitting formulas for resistance and splash performance of WCD are reported.
基金the Fundamental Research Funds for the Central Universities(30918012201)the Fund of the State Key Laboratory(6142604190302).
文摘In this paper,the fow physics and impact dynamics of a sphere bouncing on a water surface are studied experimentally.During the experiments,high-speed camera photography techniques are used to capture the cavity and free surface evolution when the sphere impacts and skips on the water surface.The infuences of the impact velocity(v_(1))and impact angle(θ_(1))of the sphere on the bouncing fow physics are also investigated,including the cavitation evolution,motion characteristics,and bounding law.Regulations for the relationship between v_(1)andθ_(1)to judge whether the sphere can bounce on the water surface are presented and analyzed by summarizing a large amount of experimental data.In addition,the efect ofθ_(1)on the energy loss of the sphere is also analyzed and discussed.The experiment results show that there is a ftted curve of v_(1)=17.5θ_(1)−45.5 determining the relationship between the critical initial velocity and angle whether the sphere bounces on the water surface.
文摘There is some discussion as to whether exercise-induced hyperthermia of the superficial digital flexor tendon (SDFT) affects tenocyte viability and pre-disposes to injury. Cold-therapy is commonly used as a preventative measure and treatment for acute tendon injuries, but only a few studies have evaluated the effect of cold-therapy on metacarpal temperatures in the horse. For this reason, this study has measured skin surface temperatures after moderate exercise and after application of cold-therapy, and additionally monitored the duration of any effects. Four horses were recruited into a semi blinded controlled study with repeated measurements that involved lunged exercise for 16 minutes at moderate intensity. Skin surface temperature was measured using a thermographic camera before and after lunging, and every 40 minutes for two hours post cold-therapy. Cold-therapy was applied using a Jacks Whirlpool Boot with ice-water immersion at a level just distal to the carpus for 20 minutes. The right leg was treated, and the left leg was used as an untreated control. The experiment was conducted twice on all four horses. Moderate exercise resulted in an increase in skin surface temperature of 10<sup>°</sup>C. Application of cold-therapy for 20 minutes resulted in a reduction in skin surface temperature by 14<sup>°</sup>C. The effect of cold-therapy persisted for at least 40 minutes post treatment. It is concluded that exercise leads to an increase in skin surface temperature which is counteracted by the application of cold-therapy. These findings would seem to indicate that cold-therapy can be used after exercise to counteract hyperthermia within the metacarpal region of the horse’s leg.
文摘Water activity-temperature relationships are reported for Yukon soil-isolated strains of Mortierella alpina and Penicillium expansum that are natural enemies to larvae(infestation stage)of the winter tick Dermacentor albipictus.Both fungal strains are psychrotrophs,characterized by low thermal growth ranges,consistent with their occurrence in Yukon soil.In contrast to P.expansum,M.alpina is more temperature sensitive,has a higher requirement,and is more virulent to tick larvae.Researchers and Biological Control Officers should note that for tick population control these M.alpina and P.expansum strains grow and sporulate well under moderate temperature and humid conditions.Our experiments used Met52®Bioinsecticide as a positive control,and this is the first study that demonstrates the effectiveness of this commercial product against winter tick larvae.
文摘The effects of lance height and bottom blown flowrate on the mixed time, the splashing amount, the penetrating depth, and the level fluctuation of an 85 t combined blown converter have been studied using a water model. The results show that the maximal stirring energy is provided to the bath at the top lance height of about 50-100 mm. When the top lance height is in the range ofg0- 110 mm, the splashing amount caused by the top jet can reach the maximal value. The appropriate operational parameters of Chongqing Iron and Steel Company （CISC） converter have been established that the top lance height is 1600-1760 mm and the bottom blowing flowrate is 240-480 Nm^3/h in the primary phase of a heat, 1100-1300 mm and 160-200 Nm^3/h in the second phase, and 1040-1120 mm and 200-350 Nm^3/h in the end phase. Also, the trial shows that the metallurgical result of the studied blow pattern is better than that of the former pattern. At the starting 3-4 min of a heat, the strong splashing is eliminated. 2008 University of Science and Technology Beijing. All rights reserved.
