Joint experiments(JEs)on small tokamaks have been regularly performed between 2005 and 2015 under the framework of the International Atomic Energy Agency(IAEA)coordinated research projects(CRPs).This paper describes t...Joint experiments(JEs)on small tokamaks have been regularly performed between 2005 and 2015 under the framework of the International Atomic Energy Agency(IAEA)coordinated research projects(CRPs).This paper describes the background and the rationale for these experiments,how they were organized and executed,main areas of research covered during these experiments,main results,contributions to mainstream fusion research,and discusses lessons learned and outcomes from these activities.We underline several of the most important scientific outputs and also specific outputs in the education of young scientists and scientists from developing countries and their importance.展开更多
In order to investigate the laws of variation on tensile strength of butt welded joint post high temperatures, the wide plate tension tests for butt welded joint were conducted after cooling down from different high t...In order to investigate the laws of variation on tensile strength of butt welded joint post high temperatures, the wide plate tension tests for butt welded joint were conducted after cooling down from different high temperatures. The tests indicate that specimens appear ductile fracture at the steel plate during the tension tests after cooling down. The maximum temperatures undergone and the cooling pattern are major factors influencing tensile strength of butt welded joint post high temperatures. The tensile strength mostly reduces by 8% within 900℃. Based on the experimental results, the paper proposes the calculation formulas of tensile strength of butt welded joint post high temperatures. The conclusions of the paper supply references for evaluation damage and reinforcement of steel structure post fire.展开更多
Loal flexibility of tubular joints has important effect on the static and dynamic behaviour of offshore platforms, therefore, the determination of it becomes an important research subject in the field of offshore engi...Loal flexibility of tubular joints has important effect on the static and dynamic behaviour of offshore platforms, therefore, the determination of it becomes an important research subject in the field of offshore engineering. In this paper, the local flexibility of TY-type tubular joints, which are widely used in offshore platforms, is calculated by using semi- analytical method. Based on the calculated results, parametric formulae for evaluating element in the local joint flexibility matrix of TY- type tubular joints are derived by regression. A test on PVC models of TY-type tubular joints to measure the local joint flexibility is also reported. A comparison of the results calculated from the parametric formulae presented in this paper with those measured from the model test shows that the parametric formulae are reliable. It is recommended that these formulae be used in the global structural analysis of offshore platforms.展开更多
A new type of semi-rigid thin-walled steel-concrete composite beam-to-column joint has been proposed in this paper.Five semi-rigid composite beam-to-column joint specimens subjected to hogging moments under monotonic ...A new type of semi-rigid thin-walled steel-concrete composite beam-to-column joint has been proposed in this paper.Five semi-rigid composite beam-to-column joint specimens subjected to hogging moments under monotonic loading were tested to study the static behavior of this new type of joint.The main variable parameters for the five joint specimens were the longitudinal reinforcement ratio and the joint type.The experimental results designated that the magnitude of extension of the longitudinal reinforcement is the most important factor that influenced the moment-rotation characteristic of the new type of joint.The concrete slabs could resist 3.8%-19.1% of the total shear load applied to the cross-sections near the beam-to-column connection.The edge stiffened elements,such as the flange of the lipped I-section thin-walled steel beam,were capable of having considerable inelastic deformation capacity although they had comparatively large width-to-thickness ratios.The shear failure of the concrete cantilever edge strip must be taken into account in practical design because it has significant influence on the anchorage of the longitudinal reinforcement in the new type of external joints.展开更多
Background: Osteoarthritis is a slowly progressive and debilitating disease with high prevalence in adult population. Knee is one of the joints most affected by this disorder. There are several models for animals’ os...Background: Osteoarthritis is a slowly progressive and debilitating disease with high prevalence in adult population. Knee is one of the joints most affected by this disorder. There are several models for animals’ osteoarthritis induction, however it is not identified any paper that compares these techniques. The present study was aimed to define the most appropriate model for rats osteoarthritis induction. Material and Methods: 40 Wistar rats were distributed into 4 groups of 10 animals each: normality group (NG);meniscectomy group (MG);quinolone group (QG) and iodoacetate group (IG). Radiographic images of the rat’s knees were analyzed as well as the amount of chondrocytes in the epiphyseal and articular cartilage. Results: In the radiographic analysis, there was a low correlation between the raters. Regarding the amount of chondrocytes in the epiphyseal cartilage, it was noticed that the IG and QG groups had fewer chondrocytes than NG, in contrast to MG that reported similar results to normality (p > 0.05). There was no significant difference between IG and QG groups (p > 0.05). Regarding the amount of chondrocytes in articular cartilage, it was noticed that the IG group showed fewer chondrocytes than NG (p 0.05). There was no significant difference between QG and MG groups (p > 0.05). Conclusion: Intraarticular injection of iodoacetate in rats is the model with greatest effect on reduction of chondrocytes amount.展开更多
The blasting experiment of the cement mortar model reveals that joint inclination affects blasted rock size distribution, which is an important index to evaluate the blasting effect. According to the fractal theory, t...The blasting experiment of the cement mortar model reveals that joint inclination affects blasted rock size distribution, which is an important index to evaluate the blasting effect. According to the fractal theory, the relationship is built up between fractal dimension and mass fraction of blasted fragments screened, that is, y x=100(x/x m ) 3-D . On the basis of the experiment results, the fractal dimension describing fragment size distribution is calculated.展开更多
Objective To observe IL-1B,IL-6 and TNF-a level change of the joint fluid in the experimental knee joint degeneration and the effect of the local loosening therapy.Methods Thirty rabbits were divided into 3 groups at ...Objective To observe IL-1B,IL-6 and TNF-a level change of the joint fluid in the experimental knee joint degeneration and the effect of the local loosening therapy.Methods Thirty rabbits were divided into 3 groups at random:ten in the normal contrast group,ten in the blank model group and ten in the loosening therapy group to observe the IL-1B,IL-6 and TNF-a change of the joint fluid before and after the treatment in each group.Result IL-1B,IL-6 and TNF-a level in the blank model group was obviously higher than that in the normal group.(P<0.05).IL-1B,IL-6 and TNF-a level in the treatment group was obviously lower than that in the normal group.(P<0.05).Conclusions 1)IL-1B,IL-6 and TNF-a level of the joint fluid in the blank model group was obviously higher than that in the normal group.2)Loosening soft tissues of the knees can improve IL-1B,IL-6 and TNF-a level of the joint fluid.展开更多
In order to investigate the behavior of external welded flange-bolted web joints of steel structure exposed to fire,a series of experiments were carried out.Influence of fire model and load ratio on the behavior of th...In order to investigate the behavior of external welded flange-bolted web joints of steel structure exposed to fire,a series of experiments were carried out.Influence of fire model and load ratio on the behavior of the joints,failure characteristics and fracture modes of the joints exposed to fire were studied.The experimental results indicated that the fire model has a great influence on the temperature rising as well as temperature distribution of the joints exposed to fire.A slower temperature rising fire will lead to slower temperature rising and more uniform temperature distribution of joint.Decrease of the load ratio will improve the fire-resistant capability of the joint.Furthermore,a highly detailed three-dimensional(3-D) finite element model(FEM) was set up with ANSYS software to predict the behavior of the external welded flange-bolted web joints exposed to fire.Comparisons between the predicted results and the experimental results indicated that FEM has an acceptable degree of accuracy to predict the behavior of this type of joints exposed to fire.展开更多
In order to evaluate the influence of the surface morphology on the mechanical behavior of twelve natural marble joints, very accurate topography measurements of joint surfaces under constant normal load （CNL） condi...In order to evaluate the influence of the surface morphology on the mechanical behavior of twelve natural marble joints, very accurate topography measurements of joint surfaces under constant normal load （CNL） conditions were performed before and after shear tests. The surface topography was carried out using a three-dimensional （3D） laser-scanning profilometer with a parallel grid at a regular interval of 500 gin. Each surface before shearing was reconstructed by geostatistical methods according to eight different directions. A quantitative description of surfaces was performed using global and directional statistical parameters. These parameters allow to determine the surface anisotropy and to divide the .joints into three groups of similar morphology according to a given direction. Each sample of the same group is submitted to the same normal stress but to different shear rates ranging from 5 to 20 gm/s. The influences of normal stress and shear rate on the mechanical behavior of the discontinuities were investigated, as well as the influence of the sample morphology on its dilatancy behavior. The morphology data of upper and lower walls also permit to quantify the contact areas before testing. After the shear tests, sheared surfaces were scanned again and reconstructed according to the shearing direction. Based on the topography data of joint surfaces obtained before and after shearing, damage zones that occurred during shearing were located for both walls of each .joint. These characterizations of joint surfaces contribute to a better understanding of the shearing behavior of natural discontinuities.展开更多
基金supported by funding by the IAEA technical contracts within IAEA Coordinated Research Projects on‘Joint Research Using Small Tokamaks’and on‘Utilisation of a Network of Small Magnetic Confinement Fusion Devices for Mainstream Fusion Research’funded by Russian Science Foundation,Project 19-12-00312+3 种基金partly supported by the Competitiveness Program of NRNU MEPhIthe partial financial support from MEPhI and NRU MPEI in the framework of the Russian Academic Excellence Projectsupported by Tokamak Energy LtdOxford Instruments(UK)。
文摘Joint experiments(JEs)on small tokamaks have been regularly performed between 2005 and 2015 under the framework of the International Atomic Energy Agency(IAEA)coordinated research projects(CRPs).This paper describes the background and the rationale for these experiments,how they were organized and executed,main areas of research covered during these experiments,main results,contributions to mainstream fusion research,and discusses lessons learned and outcomes from these activities.We underline several of the most important scientific outputs and also specific outputs in the education of young scientists and scientists from developing countries and their importance.
文摘In order to investigate the laws of variation on tensile strength of butt welded joint post high temperatures, the wide plate tension tests for butt welded joint were conducted after cooling down from different high temperatures. The tests indicate that specimens appear ductile fracture at the steel plate during the tension tests after cooling down. The maximum temperatures undergone and the cooling pattern are major factors influencing tensile strength of butt welded joint post high temperatures. The tensile strength mostly reduces by 8% within 900℃. Based on the experimental results, the paper proposes the calculation formulas of tensile strength of butt welded joint post high temperatures. The conclusions of the paper supply references for evaluation damage and reinforcement of steel structure post fire.
文摘Loal flexibility of tubular joints has important effect on the static and dynamic behaviour of offshore platforms, therefore, the determination of it becomes an important research subject in the field of offshore engineering. In this paper, the local flexibility of TY-type tubular joints, which are widely used in offshore platforms, is calculated by using semi- analytical method. Based on the calculated results, parametric formulae for evaluating element in the local joint flexibility matrix of TY- type tubular joints are derived by regression. A test on PVC models of TY-type tubular joints to measure the local joint flexibility is also reported. A comparison of the results calculated from the parametric formulae presented in this paper with those measured from the model test shows that the parametric formulae are reliable. It is recommended that these formulae be used in the global structural analysis of offshore platforms.
基金Sponsored by the National Natural Science Foundation of China (Grant No.50478027)
文摘A new type of semi-rigid thin-walled steel-concrete composite beam-to-column joint has been proposed in this paper.Five semi-rigid composite beam-to-column joint specimens subjected to hogging moments under monotonic loading were tested to study the static behavior of this new type of joint.The main variable parameters for the five joint specimens were the longitudinal reinforcement ratio and the joint type.The experimental results designated that the magnitude of extension of the longitudinal reinforcement is the most important factor that influenced the moment-rotation characteristic of the new type of joint.The concrete slabs could resist 3.8%-19.1% of the total shear load applied to the cross-sections near the beam-to-column connection.The edge stiffened elements,such as the flange of the lipped I-section thin-walled steel beam,were capable of having considerable inelastic deformation capacity although they had comparatively large width-to-thickness ratios.The shear failure of the concrete cantilever edge strip must be taken into account in practical design because it has significant influence on the anchorage of the longitudinal reinforcement in the new type of external joints.
文摘Background: Osteoarthritis is a slowly progressive and debilitating disease with high prevalence in adult population. Knee is one of the joints most affected by this disorder. There are several models for animals’ osteoarthritis induction, however it is not identified any paper that compares these techniques. The present study was aimed to define the most appropriate model for rats osteoarthritis induction. Material and Methods: 40 Wistar rats were distributed into 4 groups of 10 animals each: normality group (NG);meniscectomy group (MG);quinolone group (QG) and iodoacetate group (IG). Radiographic images of the rat’s knees were analyzed as well as the amount of chondrocytes in the epiphyseal and articular cartilage. Results: In the radiographic analysis, there was a low correlation between the raters. Regarding the amount of chondrocytes in the epiphyseal cartilage, it was noticed that the IG and QG groups had fewer chondrocytes than NG, in contrast to MG that reported similar results to normality (p > 0.05). There was no significant difference between IG and QG groups (p > 0.05). Regarding the amount of chondrocytes in articular cartilage, it was noticed that the IG group showed fewer chondrocytes than NG (p 0.05). There was no significant difference between QG and MG groups (p > 0.05). Conclusion: Intraarticular injection of iodoacetate in rats is the model with greatest effect on reduction of chondrocytes amount.
文摘The blasting experiment of the cement mortar model reveals that joint inclination affects blasted rock size distribution, which is an important index to evaluate the blasting effect. According to the fractal theory, the relationship is built up between fractal dimension and mass fraction of blasted fragments screened, that is, y x=100(x/x m ) 3-D . On the basis of the experiment results, the fractal dimension describing fragment size distribution is calculated.
基金Project(99JJy2081)supported by the Natural Science Foundation of Hunan Province
文摘Objective To observe IL-1B,IL-6 and TNF-a level change of the joint fluid in the experimental knee joint degeneration and the effect of the local loosening therapy.Methods Thirty rabbits were divided into 3 groups at random:ten in the normal contrast group,ten in the blank model group and ten in the loosening therapy group to observe the IL-1B,IL-6 and TNF-a change of the joint fluid before and after the treatment in each group.Result IL-1B,IL-6 and TNF-a level in the blank model group was obviously higher than that in the normal group.(P<0.05).IL-1B,IL-6 and TNF-a level in the treatment group was obviously lower than that in the normal group.(P<0.05).Conclusions 1)IL-1B,IL-6 and TNF-a level of the joint fluid in the blank model group was obviously higher than that in the normal group.2)Loosening soft tissues of the knees can improve IL-1B,IL-6 and TNF-a level of the joint fluid.
基金Sponsored by the National Natural Science Foundation of China(Grant No.50676089)
文摘In order to investigate the behavior of external welded flange-bolted web joints of steel structure exposed to fire,a series of experiments were carried out.Influence of fire model and load ratio on the behavior of the joints,failure characteristics and fracture modes of the joints exposed to fire were studied.The experimental results indicated that the fire model has a great influence on the temperature rising as well as temperature distribution of the joints exposed to fire.A slower temperature rising fire will lead to slower temperature rising and more uniform temperature distribution of joint.Decrease of the load ratio will improve the fire-resistant capability of the joint.Furthermore,a highly detailed three-dimensional(3-D) finite element model(FEM) was set up with ANSYS software to predict the behavior of the external welded flange-bolted web joints exposed to fire.Comparisons between the predicted results and the experimental results indicated that FEM has an acceptable degree of accuracy to predict the behavior of this type of joints exposed to fire.
文摘In order to evaluate the influence of the surface morphology on the mechanical behavior of twelve natural marble joints, very accurate topography measurements of joint surfaces under constant normal load （CNL） conditions were performed before and after shear tests. The surface topography was carried out using a three-dimensional （3D） laser-scanning profilometer with a parallel grid at a regular interval of 500 gin. Each surface before shearing was reconstructed by geostatistical methods according to eight different directions. A quantitative description of surfaces was performed using global and directional statistical parameters. These parameters allow to determine the surface anisotropy and to divide the .joints into three groups of similar morphology according to a given direction. Each sample of the same group is submitted to the same normal stress but to different shear rates ranging from 5 to 20 gm/s. The influences of normal stress and shear rate on the mechanical behavior of the discontinuities were investigated, as well as the influence of the sample morphology on its dilatancy behavior. The morphology data of upper and lower walls also permit to quantify the contact areas before testing. After the shear tests, sheared surfaces were scanned again and reconstructed according to the shearing direction. Based on the topography data of joint surfaces obtained before and after shearing, damage zones that occurred during shearing were located for both walls of each .joint. These characterizations of joint surfaces contribute to a better understanding of the shearing behavior of natural discontinuities.
