To overcome the current difficulties of high-precision machining and the high manufacturing and maintenance costs of spherical seals for deep-water drilling ball joints,a new spherical seal technique is proposed in th...To overcome the current difficulties of high-precision machining and the high manufacturing and maintenance costs of spherical seals for deep-water drilling ball joints,a new spherical seal technique is proposed in this paper.The spherical seal is mainly composed of silicone rubber and polytetrafluoroethylene(PTFE).Rational structural design makes the seal independent from the ball and other components,making it easy to replace if leakage occurs at its surface.PTFE can elastically deform over a certain deformation range,which guarantees that two sealing surfaces fit tightly together.O-Ring and PTFE elasticity makes up for any lack of accuracy during spherical machining and decreases the machining precision requirements for spherical surfaces.Using a finite element technique and nonlinear theory,the performance of the spherical seal under the influence of various factors is determined.The results show that the spherical seal designed in this paper exhibits excellent sealing performance under lowtemperature and high-pressure conditions.The spherical seal,a combination of an O-ring and PTFE,has the advantages of cheap manufacturing and maintenance costs and excellent sealing performance.展开更多
Offshore triceratops is one of the successful manifestations of the form-dominant design approaches deployable in ultra-deepwater oil and gas exploration.The deck’s geometric shape and partial isolation from the legs...Offshore triceratops is one of the successful manifestations of the form-dominant design approaches deployable in ultra-deepwater oil and gas exploration.The deck’s geometric shape and partial isolation from the legs counteract lateral loads.Legs are position-restrained to the sea bed by taut-moored tendons,while ball joints partially isolate the deck from the buoyant legs.However,compliance in the horizontal plane imposes large displacements,intuiting the necessity to examine tendon failure.Numerical analysis of triceratops under wave and wind combined action is carried out under the postulated conditions of a tendon failure.10-yr,100-yr,and 1000-yr post-Katrina hurricane conditions are assumed as loading to the platform.Results confirm a marginal increase in the natural periods of stiff degrees of freedom even under postulated failure conditions,ensuring good adaptability to ultra-deep water.Under postulated failure,the tension of adjacent tendons varies significantly,causing a shift to the mean position of the platform.Fatigue life is significantly reduced under the postulated failure of tendons,making the platform free-floating without affecting its stability.Results also show that the pitch response of the deck is a clear manifestation of the postulated failure,which is otherwise absent due to the presence of ball joints.The attempted study deliberates on the fatigue life of tendons,assessing the platform’s suitability to ultra-deep waters and identifying the vulnerable legs for the chosen load combinations.展开更多
目的:研究手臂锻炼对经外周置入中心静脉导管(Peripherally inserted central catheter,PICC)置管的食管癌化疗患者腋静脉血流速度及肩关节功能的影响。方法:选取河南科技大学第一附属医院2021年4月至2022年11月期间96例PICC置管的食管...目的:研究手臂锻炼对经外周置入中心静脉导管(Peripherally inserted central catheter,PICC)置管的食管癌化疗患者腋静脉血流速度及肩关节功能的影响。方法:选取河南科技大学第一附属医院2021年4月至2022年11月期间96例PICC置管的食管癌化疗患者随机分组(n=48),对照组给予握球锻炼,观察组联合手臂锻炼,4 w后,采用彩色多普勒超声仪测量并记录两组患者干预前后腋静脉单位时间平均血流速度(Mean flow velocity per unit time,TMFV)、最大血流速度(Maximum blood flow velocity,V_(max))水平;采用肘关节功能量表评估患者肘关节功能;采用Constant-murley肩关节评分评估两组患者肩关节功能;采用生活质量量表(Short Form 36-item Health Survey,SF-36)评估两组患者生活质量;记录机械性静脉炎、肢体肿胀、PICC相关性血栓(Peripherally inserted central catheter related venous thrombus,PICC-related VT)、PICC导管脱出等并发症发生情况。结果:与干预前相比,对照组TMFV、V_(max)水平均降低(P<0.05),观察组V_(max)、TMFV水平变化,差异无统计学意义(P>0.05),且观察组V_(max)、TMFV水平均高于对照组(P<0.05);与干预前相比,各组肘关节运动功能、日常活动、疼痛程度评分、肩关节肌力、肩关节活动度、日常活动水平、疼痛程度评分、SF-36评分均升高,其中观察组更为显著(P<0.05);干预4 w内,两组患者机械性静脉炎、肢体肿胀、PICC导管脱出发生率比较,差异无统计学意义(P>0.05);观察组PICC-related VT发生率低于对照组(P<0.05)。结论:手臂锻炼能够有效提高PICC置管的食管癌化疗患者腋静脉血流速度,改善肩关节和肘关节功能,降低PICC-related VT发生率,提高生活质量。展开更多
文摘To overcome the current difficulties of high-precision machining and the high manufacturing and maintenance costs of spherical seals for deep-water drilling ball joints,a new spherical seal technique is proposed in this paper.The spherical seal is mainly composed of silicone rubber and polytetrafluoroethylene(PTFE).Rational structural design makes the seal independent from the ball and other components,making it easy to replace if leakage occurs at its surface.PTFE can elastically deform over a certain deformation range,which guarantees that two sealing surfaces fit tightly together.O-Ring and PTFE elasticity makes up for any lack of accuracy during spherical machining and decreases the machining precision requirements for spherical surfaces.Using a finite element technique and nonlinear theory,the performance of the spherical seal under the influence of various factors is determined.The results show that the spherical seal designed in this paper exhibits excellent sealing performance under lowtemperature and high-pressure conditions.The spherical seal,a combination of an O-ring and PTFE,has the advantages of cheap manufacturing and maintenance costs and excellent sealing performance.
文摘Offshore triceratops is one of the successful manifestations of the form-dominant design approaches deployable in ultra-deepwater oil and gas exploration.The deck’s geometric shape and partial isolation from the legs counteract lateral loads.Legs are position-restrained to the sea bed by taut-moored tendons,while ball joints partially isolate the deck from the buoyant legs.However,compliance in the horizontal plane imposes large displacements,intuiting the necessity to examine tendon failure.Numerical analysis of triceratops under wave and wind combined action is carried out under the postulated conditions of a tendon failure.10-yr,100-yr,and 1000-yr post-Katrina hurricane conditions are assumed as loading to the platform.Results confirm a marginal increase in the natural periods of stiff degrees of freedom even under postulated failure conditions,ensuring good adaptability to ultra-deep water.Under postulated failure,the tension of adjacent tendons varies significantly,causing a shift to the mean position of the platform.Fatigue life is significantly reduced under the postulated failure of tendons,making the platform free-floating without affecting its stability.Results also show that the pitch response of the deck is a clear manifestation of the postulated failure,which is otherwise absent due to the presence of ball joints.The attempted study deliberates on the fatigue life of tendons,assessing the platform’s suitability to ultra-deep waters and identifying the vulnerable legs for the chosen load combinations.
文摘目的:研究手臂锻炼对经外周置入中心静脉导管(Peripherally inserted central catheter,PICC)置管的食管癌化疗患者腋静脉血流速度及肩关节功能的影响。方法:选取河南科技大学第一附属医院2021年4月至2022年11月期间96例PICC置管的食管癌化疗患者随机分组(n=48),对照组给予握球锻炼,观察组联合手臂锻炼,4 w后,采用彩色多普勒超声仪测量并记录两组患者干预前后腋静脉单位时间平均血流速度(Mean flow velocity per unit time,TMFV)、最大血流速度(Maximum blood flow velocity,V_(max))水平;采用肘关节功能量表评估患者肘关节功能;采用Constant-murley肩关节评分评估两组患者肩关节功能;采用生活质量量表(Short Form 36-item Health Survey,SF-36)评估两组患者生活质量;记录机械性静脉炎、肢体肿胀、PICC相关性血栓(Peripherally inserted central catheter related venous thrombus,PICC-related VT)、PICC导管脱出等并发症发生情况。结果:与干预前相比,对照组TMFV、V_(max)水平均降低(P<0.05),观察组V_(max)、TMFV水平变化,差异无统计学意义(P>0.05),且观察组V_(max)、TMFV水平均高于对照组(P<0.05);与干预前相比,各组肘关节运动功能、日常活动、疼痛程度评分、肩关节肌力、肩关节活动度、日常活动水平、疼痛程度评分、SF-36评分均升高,其中观察组更为显著(P<0.05);干预4 w内,两组患者机械性静脉炎、肢体肿胀、PICC导管脱出发生率比较,差异无统计学意义(P>0.05);观察组PICC-related VT发生率低于对照组(P<0.05)。结论:手臂锻炼能够有效提高PICC置管的食管癌化疗患者腋静脉血流速度,改善肩关节和肘关节功能,降低PICC-related VT发生率,提高生活质量。
