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
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.
