In petroleum extraction,the sealing surfaces of bolted joints are susceptible to damage due to the high-temperature and high-pressure conditions in wellbores.This damage adversely affects sealing performance,consequen...In petroleum extraction,the sealing surfaces of bolted joints are susceptible to damage due to the high-temperature and high-pressure conditions in wellbores.This damage adversely affects sealing performance,consequently leading to the failure and damage of threaded connections.In severe cases,it can result in considerable economic losses and trigger safety accidents.The sealing performance of special bolted joints holds crucial importance for production efficiency,output,equipment lifespan,and cost control.Enhancing the sealing perfor-mance of threaded connections can have a positive impact on industrial production and environmental protection.The existing research on American Petroleum Institute threaded joints has been thorough and has obtained a series of excellent results.However,the research on the sealing damage mechanism of threaded connections under complex well conditions lacks sufficient depth and that on new sealing technology is scarce.This study proposes a half-size evaluation test to address the abovementioned problem.Based on this test,an investigation into the sealing performance of threaded connections under high-temperature,cyclic loading,and high-temperature creep conditions is conducted.This study uses a combined approach of finite element methods and experiments to investigate the impact of different makeup torques on the sealing performance of premium threaded connections(PTCs).The results of the half-size evaluation test indicate that temperature notably influences the sealing performance of threaded connections.The continuous action of high temperatures causes contact pressure and sealing performance to decrease,and sealing contact pressure increases after cooling.Finite element and test results show that for a certain joint A,the greater the torque,the higher the critical sealing pressure of the thread,and the better the sealing performance.The research on the sealing damage mechanism of PTCs provides a scientific basis and theoretical guidance for the further optimization and development of PTCs.展开更多
White-brown complex （WBC） transporters, also called half-size ATP binding cassette G （ABCG） transporters, are involved in many biological processes, including seed development; however, the WBC transporters in gra...White-brown complex （WBC） transporters, also called half-size ATP binding cassette G （ABCG） transporters, are involved in many biological processes, including seed development; however, the WBC transporters in grapevines received less attention to date. To reveal the molecular characteristics of WBCs and the connection between WBCs and agronomic traits of stenospermocarpic （seedless） grapevine, we carried out a genomic census and analysis of ovule-associated expression for VvWBC genes in grapevine. We identified 30 VvWBC genes and cloned full-length complementary DNAs （cDNAs） for 20 of these. The tissue or organ-specific expression analysis showed that several VvWBCs exhibited distinct expression patterns with some showing tissue specificity. Twelve VvWBC genes were found to be expressed in the developing ovules. Moreover, the results of quantitative real-time PCR （qRT-PCR） suggested that four of twelve ovule-expressed VvWBCs have distinct expression profiles during the development of ovules between seeded and stenospermocarpic grapevines. These four genes might be involved in ovule abortion. Meanwhile, chromosome mapping, multiple sequence alignments, exon/intron structure analyses and synteny analyses were preformed on VvWBC genes. Our experiments provide a new perspective on the mechanism of stenospermocarpic seedlessness and put forward a framework for further study of WBC transporters.展开更多
文摘In petroleum extraction,the sealing surfaces of bolted joints are susceptible to damage due to the high-temperature and high-pressure conditions in wellbores.This damage adversely affects sealing performance,consequently leading to the failure and damage of threaded connections.In severe cases,it can result in considerable economic losses and trigger safety accidents.The sealing performance of special bolted joints holds crucial importance for production efficiency,output,equipment lifespan,and cost control.Enhancing the sealing perfor-mance of threaded connections can have a positive impact on industrial production and environmental protection.The existing research on American Petroleum Institute threaded joints has been thorough and has obtained a series of excellent results.However,the research on the sealing damage mechanism of threaded connections under complex well conditions lacks sufficient depth and that on new sealing technology is scarce.This study proposes a half-size evaluation test to address the abovementioned problem.Based on this test,an investigation into the sealing performance of threaded connections under high-temperature,cyclic loading,and high-temperature creep conditions is conducted.This study uses a combined approach of finite element methods and experiments to investigate the impact of different makeup torques on the sealing performance of premium threaded connections(PTCs).The results of the half-size evaluation test indicate that temperature notably influences the sealing performance of threaded connections.The continuous action of high temperatures causes contact pressure and sealing performance to decrease,and sealing contact pressure increases after cooling.Finite element and test results show that for a certain joint A,the greater the torque,the higher the critical sealing pressure of the thread,and the better the sealing performance.The research on the sealing damage mechanism of PTCs provides a scientific basis and theoretical guidance for the further optimization and development of PTCs.
基金supported by the National Natural Science Foundation of China (31372023)the earmarked fund for China Agricultural Research System (CARS-30-yz-7)
文摘White-brown complex （WBC） transporters, also called half-size ATP binding cassette G （ABCG） transporters, are involved in many biological processes, including seed development; however, the WBC transporters in grapevines received less attention to date. To reveal the molecular characteristics of WBCs and the connection between WBCs and agronomic traits of stenospermocarpic （seedless） grapevine, we carried out a genomic census and analysis of ovule-associated expression for VvWBC genes in grapevine. We identified 30 VvWBC genes and cloned full-length complementary DNAs （cDNAs） for 20 of these. The tissue or organ-specific expression analysis showed that several VvWBCs exhibited distinct expression patterns with some showing tissue specificity. Twelve VvWBC genes were found to be expressed in the developing ovules. Moreover, the results of quantitative real-time PCR （qRT-PCR） suggested that four of twelve ovule-expressed VvWBCs have distinct expression profiles during the development of ovules between seeded and stenospermocarpic grapevines. These four genes might be involved in ovule abortion. Meanwhile, chromosome mapping, multiple sequence alignments, exon/intron structure analyses and synteny analyses were preformed on VvWBC genes. Our experiments provide a new perspective on the mechanism of stenospermocarpic seedlessness and put forward a framework for further study of WBC transporters.
