The influence of welding parameters of butt joints, made by three processes (MMA, MAG and T.I.M.E), on their geometric characteristics has been evaluated, which in turn caused a change of the fatigue strength. That fo...The influence of welding parameters of butt joints, made by three processes (MMA, MAG and T.I.M.E), on their geometric characteristics has been evaluated, which in turn caused a change of the fatigue strength. That fore the statistic analysis and FEM were used and a method developed in the Institute of Welding, which consist in a direct connection of parameters used during welding with the fatigue strength of joints welded by various processes. It has been proven, among others, which by using more advanced welding processes (T.I.M.E) the fatigue strength of welded joints can be increased in comparison to joints welded by MMA and MAG.展开更多
The aim of this work is to identify a substitute for imported standardized sand for determining the strength class of cements using local sands. To this end, three (03) local sands (Manga, Kaya and Dori) were characte...The aim of this work is to identify a substitute for imported standardized sand for determining the strength class of cements using local sands. To this end, three (03) local sands (Manga, Kaya and Dori) were characterized and then used to formulate sand mixtures fitting into the granular spindle of standardized sand noted SM1, SM2 and SM3. SM1 is composed of 80% Manga sand plus 20% Dori sand. SM2 is a mixture of 80% of the refusal and 20% of the passing through the 0.25 mm sieve of the Manga sand. SM3 is composed of 77% Manga sand 0.25 mm sieve refusals plus 23% Kaya sand. These sands were used to characterize a CEM II/B-M (P-L) 42.5 R cement by comparing it with the results of a standardized sand noted SS. Characterization of the local sand showed them to be less dense and more absorbent than the standardized sand. Mortars made with SM1, SM2 and SM3 thus have lower workability and bulk densities in the fresh and hardened states than the SS-based mortar, with higher porosities accessible to water after 28 days of curing. Mechanical characterization of the cement gave lower compressive strength values with local sands at 2 and 28 days cure. At 2 days cure, local sands gave 17.42 MPa, 14.68 MPa and 17.13 MPa respectively for SM1, SM2 and SM3, compared with 21.12 MPa for standard sand. At 28 days, mortars based on SM1 and SM3 sands give higher strength values than the 42.5 MPa required by standard NF EN 197-1, with 44.21 MPa and 43.17 MPa respectively, compared with 49.84 MPa for standardized sand. On this basis, correction factors have been proposed for the use of local sands in cement characterization. They nevertheless require repeatability studies before validation.展开更多
This study is carried out to appreciate the coarse elements influence of the gravel lateritic soils on the pavement behavior. The material involves not only the 0/20 mm granular particles considered in the specificati...This study is carried out to appreciate the coarse elements influence of the gravel lateritic soils on the pavement behavior. The material involves not only the 0/20 mm granular particles considered in the specifications and on the laboratory tests, but also all of the material that is actually used in the construction sites. Geotechnical characterization was leaned on five differentiated granular classes of 0/20;0/25;0/31.5;0/40 and 0/63 mm diameters. The sample of 0/40 mm gets the best compaction aptitude, while that of 0/31.5 mm reaches the greatest bearing strength and a good Optimum Moisture Content. According to the requirements and its bearing strengths, the material is usable up to subbase layer and its behavior depends on the grain size.展开更多
建设区域医疗中心是国家“十四五”规划的重要内容,是协同推进公立医院医、教、研、防、管整体水平提升的重要途径。深入了解全国区域医疗中心申报和建设情况,探讨其申报和建设过程中面临的困境及解决方案,积极推动地级市三甲医院高质...建设区域医疗中心是国家“十四五”规划的重要内容,是协同推进公立医院医、教、研、防、管整体水平提升的重要途径。深入了解全国区域医疗中心申报和建设情况,探讨其申报和建设过程中面临的困境及解决方案,积极推动地级市三甲医院高质量发展。采用态势分析法(strengths,weaknesses,opportunities and threats analysis,SWTO),从4个维度分析案例医院的内部优势、劣势、外部机会、挑战,探索地级市公立医院成功申报国家区域医疗中心的路径策略。地级市三甲医院申报区域医疗中心面临诸多困难和挑战,医院申报积极性高,牵头医院在人才、技术等方面做了充分准备,但也存在申报和建设等诸多问题,层次和结构需进一步优化、运行机制有待进一步健全、医疗服务同质化水平有待进一步提高等问题。建议政府做好资源规划,引导医院重视申报工作,强化人才培养和专科诊疗能力水平,发挥信息化支撑作用,顺利实现国家区域医疗中心的成功申报。展开更多
对现有盘形悬式绝缘子标准强度等级系列及其对应的联接结构尺寸进行了研究,通过计算拓展了更高强度等级及其联接尺寸,从钢脚、铁帽和绝缘件三者强度配合的正态分布曲线规律分析了提高产品强度的途径,在绝缘件标准差小的前提下分析了随...对现有盘形悬式绝缘子标准强度等级系列及其对应的联接结构尺寸进行了研究,通过计算拓展了更高强度等级及其联接尺寸,从钢脚、铁帽和绝缘件三者强度配合的正态分布曲线规律分析了提高产品强度的途径,在绝缘件标准差小的前提下分析了随着脚杆尺寸增大其公差也增大对钢脚强度分散性的影响,提出了700 k N以上强度等级对应36号联接标记的系列补充方案和其钢脚、铁帽的强度配合方案,建议了脚杆公差的设定值,也为今后国行标乃至IEC标准修订提供参考。展开更多
文摘The influence of welding parameters of butt joints, made by three processes (MMA, MAG and T.I.M.E), on their geometric characteristics has been evaluated, which in turn caused a change of the fatigue strength. That fore the statistic analysis and FEM were used and a method developed in the Institute of Welding, which consist in a direct connection of parameters used during welding with the fatigue strength of joints welded by various processes. It has been proven, among others, which by using more advanced welding processes (T.I.M.E) the fatigue strength of welded joints can be increased in comparison to joints welded by MMA and MAG.
文摘The aim of this work is to identify a substitute for imported standardized sand for determining the strength class of cements using local sands. To this end, three (03) local sands (Manga, Kaya and Dori) were characterized and then used to formulate sand mixtures fitting into the granular spindle of standardized sand noted SM1, SM2 and SM3. SM1 is composed of 80% Manga sand plus 20% Dori sand. SM2 is a mixture of 80% of the refusal and 20% of the passing through the 0.25 mm sieve of the Manga sand. SM3 is composed of 77% Manga sand 0.25 mm sieve refusals plus 23% Kaya sand. These sands were used to characterize a CEM II/B-M (P-L) 42.5 R cement by comparing it with the results of a standardized sand noted SS. Characterization of the local sand showed them to be less dense and more absorbent than the standardized sand. Mortars made with SM1, SM2 and SM3 thus have lower workability and bulk densities in the fresh and hardened states than the SS-based mortar, with higher porosities accessible to water after 28 days of curing. Mechanical characterization of the cement gave lower compressive strength values with local sands at 2 and 28 days cure. At 2 days cure, local sands gave 17.42 MPa, 14.68 MPa and 17.13 MPa respectively for SM1, SM2 and SM3, compared with 21.12 MPa for standard sand. At 28 days, mortars based on SM1 and SM3 sands give higher strength values than the 42.5 MPa required by standard NF EN 197-1, with 44.21 MPa and 43.17 MPa respectively, compared with 49.84 MPa for standardized sand. On this basis, correction factors have been proposed for the use of local sands in cement characterization. They nevertheless require repeatability studies before validation.
文摘This study is carried out to appreciate the coarse elements influence of the gravel lateritic soils on the pavement behavior. The material involves not only the 0/20 mm granular particles considered in the specifications and on the laboratory tests, but also all of the material that is actually used in the construction sites. Geotechnical characterization was leaned on five differentiated granular classes of 0/20;0/25;0/31.5;0/40 and 0/63 mm diameters. The sample of 0/40 mm gets the best compaction aptitude, while that of 0/31.5 mm reaches the greatest bearing strength and a good Optimum Moisture Content. According to the requirements and its bearing strengths, the material is usable up to subbase layer and its behavior depends on the grain size.
文摘建设区域医疗中心是国家“十四五”规划的重要内容,是协同推进公立医院医、教、研、防、管整体水平提升的重要途径。深入了解全国区域医疗中心申报和建设情况,探讨其申报和建设过程中面临的困境及解决方案,积极推动地级市三甲医院高质量发展。采用态势分析法(strengths,weaknesses,opportunities and threats analysis,SWTO),从4个维度分析案例医院的内部优势、劣势、外部机会、挑战,探索地级市公立医院成功申报国家区域医疗中心的路径策略。地级市三甲医院申报区域医疗中心面临诸多困难和挑战,医院申报积极性高,牵头医院在人才、技术等方面做了充分准备,但也存在申报和建设等诸多问题,层次和结构需进一步优化、运行机制有待进一步健全、医疗服务同质化水平有待进一步提高等问题。建议政府做好资源规划,引导医院重视申报工作,强化人才培养和专科诊疗能力水平,发挥信息化支撑作用,顺利实现国家区域医疗中心的成功申报。
文摘对现有盘形悬式绝缘子标准强度等级系列及其对应的联接结构尺寸进行了研究,通过计算拓展了更高强度等级及其联接尺寸,从钢脚、铁帽和绝缘件三者强度配合的正态分布曲线规律分析了提高产品强度的途径,在绝缘件标准差小的前提下分析了随着脚杆尺寸增大其公差也增大对钢脚强度分散性的影响,提出了700 k N以上强度等级对应36号联接标记的系列补充方案和其钢脚、铁帽的强度配合方案,建议了脚杆公差的设定值,也为今后国行标乃至IEC标准修订提供参考。
