Several well-publicized cases of improper cleaning,disinfection or sterilization of contaminated reusable medical equipment that posed an increased risk of patientto-patient disease transmission were reported within t...Several well-publicized cases of improper cleaning,disinfection or sterilization of contaminated reusable medical equipment that posed an increased risk of patientto-patient disease transmission were reported within the past few years,resulting in the notification of approximately 20 000 patients.These medical errors,the specific infection-control standards they breached,and assessments of the risk of infection associated with each are discussed.Other topics discussed include the Food and Drug Administration’s(FDA)regulation of medical devices and infection-control products;the use of adulterated,misbranded,and investigational devices;consent decrees and associated Certificates of Medical Necessity;and informed patient consent.Focus is placed on liquid chemical sterilization,its history,and the FDA’s recent censure and discontinuation of a medical device labeled with this claim,namely,the STERIS System 1 processor.Recommendations are provided for healthcare facilities,regulatory agencies,manufacturers of reusable medical devices,and professional healthcare organizations and administrations to improve public health and prevent healthcareassociated infections.展开更多
The definitions, methodology, applications, and perspectives of process systems engineering are discussed from a strategic point of view. The focal points in future development of process systems engineering are to br...The definitions, methodology, applications, and perspectives of process systems engineering are discussed from a strategic point of view. The focal points in future development of process systems engineering are to break through in methodology, to expand application fields, and to develop a new generation of process simulation systems.展开更多
In view of complex geological characteristics and alternating loading conditions associated with cyclic large amount of gas injection and withdrawal in underground gas storage(UGS) of China, a series of key gas storag...In view of complex geological characteristics and alternating loading conditions associated with cyclic large amount of gas injection and withdrawal in underground gas storage(UGS) of China, a series of key gas storage construction technologies were established, mainly including UGS site selection and evaluation, key index design, well drilling and completion, surface engineering and operational risk warning and assessment, etc. The effect of field application was discussed and summarized. Firstly, trap dynamic sealing capacity evaluation technology for conversion of UGS from the fault depleted or partially depleted gas reservoirs. A key index design method mainly based on the effective gas storage capacity design for water flooded heterogeneous gas reservoirs was proposed. To effectively guide the engineering construction of UGS, the safe well drilling, high quality cementing and high pressure and large flow surface injection and production engineering optimization suitable for long-term alternate loading condition and ultra-deep and ultra-low temperature formation were developed. The core surface equipment like high pressure gas injection compressor can be manufactured by our own. Last, the full-system operational risk warning and assessment technology for UGS was set up. The above 5 key technologies have been utilized in site selection, development scheme design, engineering construction and annual operations of 6 UGS groups, e.g. the Hutubi UGS in Xinjiang. To date, designed main indexes are highly consistent with actural performance, the 6 UGS groups have the load capacity of over 7.5 billion cubic meters of working gas volume and all the storage facilities have been running efficiently and safely.展开更多
The research on the output rate performance limit of the multi-stage energy conversion system based on modern optimal control theory is one of the hot spots of finite time thermodynamics.The existing research mainly f...The research on the output rate performance limit of the multi-stage energy conversion system based on modern optimal control theory is one of the hot spots of finite time thermodynamics.The existing research mainly focuses on the multi-stage heat engine system with pure heat transfer and the multi-stage isothermal chemical engine(ICE)system with pure mass transfer,while the multi-stage non ICE system with heat and mass transfer coupling is less involved.A multistage endoreversible non-isothermal chemical engine(ENICE)system with a finite high-chemical-potential(HCP)source(driving fluid)and an infinite low-chemical-potential sink(environment)is researched.The multistage continuous system is treated as infinitesimal ENICEs located continuously.Each infinitesimal ENICE is assumed to be a single-stage ENICE with stationary reservoirs.Extending single-stage results,the maximum power output(MPO)of the multistage system is obtained.Heat and mass transfer processes between the reservoir and working fluid are assumed to obey Onsager equations.For the fixed initial time,fixed initial fluid temperature,and fixed initial concentration of key component(CKC)in the HCP source,continuous and discrete models of the multistage system are optimized.With given initial reservoir temperature,initial CKC,and total process time,the MPO of the multistage ENICE system is optimized with fixed and free final temperature and final concentration.If the final concentration and final temperature are free,there are optimal final temperature and optimal final concentration for the multistage ENICE system to achieve MPO;meanwhile,there are low limit values for final fluid temperature and final concentration.Special cases for multistage endoreversible Carnot heat engines and ICE systems are further obtained.For the model in this paper,the minimum entropy generation objective is not equivalent to MPO objective.展开更多
文摘Several well-publicized cases of improper cleaning,disinfection or sterilization of contaminated reusable medical equipment that posed an increased risk of patientto-patient disease transmission were reported within the past few years,resulting in the notification of approximately 20 000 patients.These medical errors,the specific infection-control standards they breached,and assessments of the risk of infection associated with each are discussed.Other topics discussed include the Food and Drug Administration’s(FDA)regulation of medical devices and infection-control products;the use of adulterated,misbranded,and investigational devices;consent decrees and associated Certificates of Medical Necessity;and informed patient consent.Focus is placed on liquid chemical sterilization,its history,and the FDA’s recent censure and discontinuation of a medical device labeled with this claim,namely,the STERIS System 1 processor.Recommendations are provided for healthcare facilities,regulatory agencies,manufacturers of reusable medical devices,and professional healthcare organizations and administrations to improve public health and prevent healthcareassociated infections.
文摘The definitions, methodology, applications, and perspectives of process systems engineering are discussed from a strategic point of view. The focal points in future development of process systems engineering are to break through in methodology, to expand application fields, and to develop a new generation of process simulation systems.
基金Supported by the CNPC Science and Technology Major Project(2015E-4002)
文摘In view of complex geological characteristics and alternating loading conditions associated with cyclic large amount of gas injection and withdrawal in underground gas storage(UGS) of China, a series of key gas storage construction technologies were established, mainly including UGS site selection and evaluation, key index design, well drilling and completion, surface engineering and operational risk warning and assessment, etc. The effect of field application was discussed and summarized. Firstly, trap dynamic sealing capacity evaluation technology for conversion of UGS from the fault depleted or partially depleted gas reservoirs. A key index design method mainly based on the effective gas storage capacity design for water flooded heterogeneous gas reservoirs was proposed. To effectively guide the engineering construction of UGS, the safe well drilling, high quality cementing and high pressure and large flow surface injection and production engineering optimization suitable for long-term alternate loading condition and ultra-deep and ultra-low temperature formation were developed. The core surface equipment like high pressure gas injection compressor can be manufactured by our own. Last, the full-system operational risk warning and assessment technology for UGS was set up. The above 5 key technologies have been utilized in site selection, development scheme design, engineering construction and annual operations of 6 UGS groups, e.g. the Hutubi UGS in Xinjiang. To date, designed main indexes are highly consistent with actural performance, the 6 UGS groups have the load capacity of over 7.5 billion cubic meters of working gas volume and all the storage facilities have been running efficiently and safely.
基金supported by the National Natural Science Foundation of China(Grant Nos.51976235 and 52171317)。
文摘The research on the output rate performance limit of the multi-stage energy conversion system based on modern optimal control theory is one of the hot spots of finite time thermodynamics.The existing research mainly focuses on the multi-stage heat engine system with pure heat transfer and the multi-stage isothermal chemical engine(ICE)system with pure mass transfer,while the multi-stage non ICE system with heat and mass transfer coupling is less involved.A multistage endoreversible non-isothermal chemical engine(ENICE)system with a finite high-chemical-potential(HCP)source(driving fluid)and an infinite low-chemical-potential sink(environment)is researched.The multistage continuous system is treated as infinitesimal ENICEs located continuously.Each infinitesimal ENICE is assumed to be a single-stage ENICE with stationary reservoirs.Extending single-stage results,the maximum power output(MPO)of the multistage system is obtained.Heat and mass transfer processes between the reservoir and working fluid are assumed to obey Onsager equations.For the fixed initial time,fixed initial fluid temperature,and fixed initial concentration of key component(CKC)in the HCP source,continuous and discrete models of the multistage system are optimized.With given initial reservoir temperature,initial CKC,and total process time,the MPO of the multistage ENICE system is optimized with fixed and free final temperature and final concentration.If the final concentration and final temperature are free,there are optimal final temperature and optimal final concentration for the multistage ENICE system to achieve MPO;meanwhile,there are low limit values for final fluid temperature and final concentration.Special cases for multistage endoreversible Carnot heat engines and ICE systems are further obtained.For the model in this paper,the minimum entropy generation objective is not equivalent to MPO objective.
