One issue with layer application of roller compacted concrete(RCC)is the development of cold joints,which can cause damage to RCC structures.In this study,fly ash was used in place of 0%,20%,40%,and 60%of the cement o...One issue with layer application of roller compacted concrete(RCC)is the development of cold joints,which can cause damage to RCC structures.In this study,fly ash was used in place of 0%,20%,40%,and 60%of the cement or aggregate to examine the impact of interlayer cold joint formation on RCC mixtures.To promote cold joint formation,the second layer was placed and compacted with a delay of 0,60,120,or 180 min after the first layer.Three methods were tried for preventing cold joints from forming:one was to apply a bedding mortar to the interlayer,another was to add a set retarder admixture,and the third was to spray an adhesion-enhancing chemical additive on the surface of the first layer.Based on the 28 d specimens’compressive and splitting-tensile strengths as well as the depth of water penetration under pressure,the most effective method was found to be applying interlayer bedding mortar.Considering 180 min delayed layer castings,the splitting-tensile and compressive strengths of the control samples decreased by 31%and 17%,respectively,while the strengths of mixtures applying interlayer bedding mortar decreased by 9%and 10%.In addition,bedding mortar treatment decreased the water permeability by 59%compared to the control.Interlayer cold joint decreased all mixtures’moduli of elasticity,regardless of the age of the specimens.When the interlayer delay was 60 min,the modulus of elasticity decreased by 1%–4%.It was between 2%and 14%,and between 10%and 24%at 120 and 180 min for the interlayer delay.The longer the delay in placing the second RCC layer,the more detrimental the effect of the cold joint.This effect was most noticeable on mechanical and permeability properties tested with applied load or water pressure parallel to the cold joint,such as flexural and splitting tensile strengths and water penetration depth under pressure.展开更多
Objective:To compare the therapeutic effect difference among dog-day moxibustion on herbs,ordinary moxibution and routine western medication in treating knee-joint osteoarthritis of yang deficiency and congealing cold...Objective:To compare the therapeutic effect difference among dog-day moxibustion on herbs,ordinary moxibution and routine western medication in treating knee-joint osteoarthritis of yang deficiency and congealing cold type.Methods:A total of 90 patients with knee-joint osteoarthritis of yang deficiency and congealing cold type were divided into dog-day moxibustion group,ordinary moxibution group and western medication group according to the registration order,and there were 30 patients in each group.Among them,the patients in the dog-day moxibustion were given dog-day moxibustion on herbs method during the dog days of 2018(July 17 to August 25).Continuous treatment was applied on the first,second and third dog-day with 5 days for each dog-day,and once for a day,and there were totally 15 times of treatment.In the same period,the patients in the ordinary moxibustion group was treated with the pure moxa stick moxibustion,and the point selection and treatment course were the same as the dog-day moxibustion group.And in the same period,the patients in the western medication group were treated with routine western medication,and the patient took orally diclofenac sodium sustained-release capsules,with 100 mg each time,once a day.The Visual Analog Scale(VAS),Western Ontario and McMaster University Arthritis Index(WOMAC),life quality score and clinical efficacy for the knee joint of the three groups before and after treatment were observed.Results:After treatment,the effective rate of the dog-day moxibustion was 93.33%,the effective rate of the ordinary moxibustion group was 83.33%,and the effective rate of the western medication group was 53.33%.Compared with pre-treatment,the VAS scores and WOMAC scores of the patients with KOA in the three groups after treatment decreased,and the differences were statistically significant(all P<0.05).There were also statistically significant differences between the VAS score,total WOMAC score,pain score,joint stiffness score and joint function score of the three groups after treatment(all P<0.05).Conclusion:The effect of dog-day moxibustion on herbs in treating knee-joint osteoarthritis of yang deficiency and congealing cold type was significantly better than ordinary moxibustion and western medication,and it was worthy of clinical promotion.展开更多
Application of weathering and cold-formed steel in transmission lines can reduce steel consumption and environmental pollution. Some advances in the studies on the weathering and cold-formed steel in transmission towe...Application of weathering and cold-formed steel in transmission lines can reduce steel consumption and environmental pollution. Some advances in the studies on the weathering and cold-formed steel in transmission tower are introduced. Firstly, corrosion-resistant tests of weathering steel samples under different simulating technical atmospheres were carried out separately for 240 hours. It shows that the corrosion degree of joint samples is higher than that of single chip samples, and the corrosion-resistant performance of weathering steel is superior to common carbon steel. The corrosion-resistance of weathering steel meets with the requirement of transmission tower. Secondly, experiments and finite element analysis for cold-formed angles and a 220kV prototype tower were completed, and the stability coeffi-cient fitting curves as well as the modification formulas of slenderness ratio for cold-formed members were determined. According to the structural characteristics of transmission towers, four sections of cold-formed angles with different sections and slenderness ratios were selected in this study. The finite element model well predicted the buckling behav-iour of the cold-formed members. Ultimate loads calculating by the fitting curve were well agreed to the experimental values, especially for the members with small slenderness ratios. Weight of the cold-formed steel tower can be reduced by more than 5 percent after considering the strength enhancement. Cost of the weathering and cold-formed steel transmission tower is nearly equivalent to that of hot-rolled steel tower with hot galvanizing.展开更多
Cold Metal Transfer technology has revolutionized the welding of dissimilar metals and thicker materials by producing improved weld bead aesthetics with controlled metal deposition and low heat-input. In this study, t...Cold Metal Transfer technology has revolutionized the welding of dissimilar metals and thicker materials by producing improved weld bead aesthetics with controlled metal deposition and low heat-input. In this study, the process, weld combinations, laser-CMT hybrid welding and applications of CMT welding are critically reviewed. Microstructure and other weld characteristics have been discussed at length for various base metal combinations. Particularly, the welding of aluminium and steel with better results has been possible with CMT Welding. The results reviewed in this article indicate that the CMT-Laser hybrid welding is more preferable to Laser or Laser hybrid welding. CMT welding has found applications in automobile industries, defence sectors and power plants as a method of additive manufacturing.展开更多
地面强冷池在飑线灾害大风的生成过程中具有重要作用,其模拟强度与模式内云微物理过程及边界层过程的参数设置密切相关。然而,由于参数的不确定性,目前仍无法对飑线系统实施合理的参数扰动。为提升对流尺度数值模式在飑线系统预报中的表...地面强冷池在飑线灾害大风的生成过程中具有重要作用,其模拟强度与模式内云微物理过程及边界层过程的参数设置密切相关。然而,由于参数的不确定性,目前仍无法对飑线系统实施合理的参数扰动。为提升对流尺度数值模式在飑线系统预报中的表现,基于WRF(The Weather Research and Forecasting Model)模式,针对飑线冷池模拟偏弱的问题,从云微物理过程和边界层过程等方案中选取5个关键参数进行敏感性试验。并在此基础上,对其中的敏感参数实施联合扰动,探讨该方法对江苏地区一次飑线过程模拟的影响。结果表明,调整影响蒸发作用的参数,能够显著改变对地面冷池的估计,其中反映雨滴大小对其下落速度影响的参数CONSTB和考虑雨滴下落时周围空气的流动对雨滴影响的参数VF1R对地面冷池的敏感性最强;在单参数和多参数联合扰动试验中,飑线冷区模拟的2 m气温相比对照试验低1—2℃,有效改善了冷池模拟偏弱的问题。此外,CONSTB和VF1R的联合扰动对预报的影响更显著,且其模拟的10 m最大风速最接近实况。上述结果表明,针对飑线冷池的多参数联合扰动方法不仅能够有效表征物理参数化方案中参数的不确定性,还能改进对冷池的模拟,进而提高对飑线大风的预报准确度。展开更多
基金gratefully acknowledge the support of the Scientific and Technological Research Council of Turkey(TUBITAK)(No.217M408)the Bursa UludağUniversity Science and Technology Centre(BAP)(No.AYP(MH)-2016/16)。
文摘One issue with layer application of roller compacted concrete(RCC)is the development of cold joints,which can cause damage to RCC structures.In this study,fly ash was used in place of 0%,20%,40%,and 60%of the cement or aggregate to examine the impact of interlayer cold joint formation on RCC mixtures.To promote cold joint formation,the second layer was placed and compacted with a delay of 0,60,120,or 180 min after the first layer.Three methods were tried for preventing cold joints from forming:one was to apply a bedding mortar to the interlayer,another was to add a set retarder admixture,and the third was to spray an adhesion-enhancing chemical additive on the surface of the first layer.Based on the 28 d specimens’compressive and splitting-tensile strengths as well as the depth of water penetration under pressure,the most effective method was found to be applying interlayer bedding mortar.Considering 180 min delayed layer castings,the splitting-tensile and compressive strengths of the control samples decreased by 31%and 17%,respectively,while the strengths of mixtures applying interlayer bedding mortar decreased by 9%and 10%.In addition,bedding mortar treatment decreased the water permeability by 59%compared to the control.Interlayer cold joint decreased all mixtures’moduli of elasticity,regardless of the age of the specimens.When the interlayer delay was 60 min,the modulus of elasticity decreased by 1%–4%.It was between 2%and 14%,and between 10%and 24%at 120 and 180 min for the interlayer delay.The longer the delay in placing the second RCC layer,the more detrimental the effect of the cold joint.This effect was most noticeable on mechanical and permeability properties tested with applied load or water pressure parallel to the cold joint,such as flexural and splitting tensile strengths and water penetration depth under pressure.
基金Supported by Research Projects of Traditional Chinese Medicine of Hubei Health and Family Planning Commission: ZY2019M035Wuhan Clinical Medical Research Project: WZ14A01
文摘Objective:To compare the therapeutic effect difference among dog-day moxibustion on herbs,ordinary moxibution and routine western medication in treating knee-joint osteoarthritis of yang deficiency and congealing cold type.Methods:A total of 90 patients with knee-joint osteoarthritis of yang deficiency and congealing cold type were divided into dog-day moxibustion group,ordinary moxibution group and western medication group according to the registration order,and there were 30 patients in each group.Among them,the patients in the dog-day moxibustion were given dog-day moxibustion on herbs method during the dog days of 2018(July 17 to August 25).Continuous treatment was applied on the first,second and third dog-day with 5 days for each dog-day,and once for a day,and there were totally 15 times of treatment.In the same period,the patients in the ordinary moxibustion group was treated with the pure moxa stick moxibustion,and the point selection and treatment course were the same as the dog-day moxibustion group.And in the same period,the patients in the western medication group were treated with routine western medication,and the patient took orally diclofenac sodium sustained-release capsules,with 100 mg each time,once a day.The Visual Analog Scale(VAS),Western Ontario and McMaster University Arthritis Index(WOMAC),life quality score and clinical efficacy for the knee joint of the three groups before and after treatment were observed.Results:After treatment,the effective rate of the dog-day moxibustion was 93.33%,the effective rate of the ordinary moxibustion group was 83.33%,and the effective rate of the western medication group was 53.33%.Compared with pre-treatment,the VAS scores and WOMAC scores of the patients with KOA in the three groups after treatment decreased,and the differences were statistically significant(all P<0.05).There were also statistically significant differences between the VAS score,total WOMAC score,pain score,joint stiffness score and joint function score of the three groups after treatment(all P<0.05).Conclusion:The effect of dog-day moxibustion on herbs in treating knee-joint osteoarthritis of yang deficiency and congealing cold type was significantly better than ordinary moxibustion and western medication,and it was worthy of clinical promotion.
文摘Application of weathering and cold-formed steel in transmission lines can reduce steel consumption and environmental pollution. Some advances in the studies on the weathering and cold-formed steel in transmission tower are introduced. Firstly, corrosion-resistant tests of weathering steel samples under different simulating technical atmospheres were carried out separately for 240 hours. It shows that the corrosion degree of joint samples is higher than that of single chip samples, and the corrosion-resistant performance of weathering steel is superior to common carbon steel. The corrosion-resistance of weathering steel meets with the requirement of transmission tower. Secondly, experiments and finite element analysis for cold-formed angles and a 220kV prototype tower were completed, and the stability coeffi-cient fitting curves as well as the modification formulas of slenderness ratio for cold-formed members were determined. According to the structural characteristics of transmission towers, four sections of cold-formed angles with different sections and slenderness ratios were selected in this study. The finite element model well predicted the buckling behav-iour of the cold-formed members. Ultimate loads calculating by the fitting curve were well agreed to the experimental values, especially for the members with small slenderness ratios. Weight of the cold-formed steel tower can be reduced by more than 5 percent after considering the strength enhancement. Cost of the weathering and cold-formed steel transmission tower is nearly equivalent to that of hot-rolled steel tower with hot galvanizing.
文摘Cold Metal Transfer technology has revolutionized the welding of dissimilar metals and thicker materials by producing improved weld bead aesthetics with controlled metal deposition and low heat-input. In this study, the process, weld combinations, laser-CMT hybrid welding and applications of CMT welding are critically reviewed. Microstructure and other weld characteristics have been discussed at length for various base metal combinations. Particularly, the welding of aluminium and steel with better results has been possible with CMT Welding. The results reviewed in this article indicate that the CMT-Laser hybrid welding is more preferable to Laser or Laser hybrid welding. CMT welding has found applications in automobile industries, defence sectors and power plants as a method of additive manufacturing.
文摘地面强冷池在飑线灾害大风的生成过程中具有重要作用,其模拟强度与模式内云微物理过程及边界层过程的参数设置密切相关。然而,由于参数的不确定性,目前仍无法对飑线系统实施合理的参数扰动。为提升对流尺度数值模式在飑线系统预报中的表现,基于WRF(The Weather Research and Forecasting Model)模式,针对飑线冷池模拟偏弱的问题,从云微物理过程和边界层过程等方案中选取5个关键参数进行敏感性试验。并在此基础上,对其中的敏感参数实施联合扰动,探讨该方法对江苏地区一次飑线过程模拟的影响。结果表明,调整影响蒸发作用的参数,能够显著改变对地面冷池的估计,其中反映雨滴大小对其下落速度影响的参数CONSTB和考虑雨滴下落时周围空气的流动对雨滴影响的参数VF1R对地面冷池的敏感性最强;在单参数和多参数联合扰动试验中,飑线冷区模拟的2 m气温相比对照试验低1—2℃,有效改善了冷池模拟偏弱的问题。此外,CONSTB和VF1R的联合扰动对预报的影响更显著,且其模拟的10 m最大风速最接近实况。上述结果表明,针对飑线冷池的多参数联合扰动方法不仅能够有效表征物理参数化方案中参数的不确定性,还能改进对冷池的模拟,进而提高对飑线大风的预报准确度。
