A computer program PRETTA “Pressurizer Transient Thermodynamics Analysis” was developed for the prediction of pressurizer under transient conditions. It is based on the solution of the conservation laws of heat and ...A computer program PRETTA “Pressurizer Transient Thermodynamics Analysis” was developed for the prediction of pressurizer under transient conditions. It is based on the solution of the conservation laws of heat and mass applied to the three separate and non equilibrium thermodynamic regions. In the program all of the important thermal-hydraulics phenomena occurring in the pressurizer: stratification of the hot water and incoming cold water, bulk flashing and condensation, wall condensation, and interfacial heat and mass transfer have been considered. The bubble rising and rain-out models are developed to describe bulk flashing and condensation, respectively. To obtain the wall condensation rate, a one-dimensional heat conduction equation is solved by the pivoting method. The presented computer program will predict the pressure-time behavior of a PWR pressurizer during a variety of transients. The results obtained from the proposed mathematical model are in good agreement with available data on the CHASHMA nuclear power plant's pressurizer performance.展开更多
A type of single neuron adaptive PID regulator with auto-tuning gain is proposed and applied to the work control of fans, waterpumps and air-pressers etc. in Handan Iron & Steel Compel China. The robusthess of ind...A type of single neuron adaptive PID regulator with auto-tuning gain is proposed and applied to the work control of fans, waterpumps and air-pressers etc. in Handan Iron & Steel Compel China. The robusthess of induStrial parameter closed-loop process controlsystems is improved, and the work quality of the systems bettered.展开更多
Objectives:Pressure ulcer(PU)is one of the most common problem among the bedridden elderly and has significantly more burden on elderly and caregivers.This study is aimed to evaluate the effects of the training progra...Objectives:Pressure ulcer(PU)is one of the most common problem among the bedridden elderly and has significantly more burden on elderly and caregivers.This study is aimed to evaluate the effects of the training program for caregivers to prevent PUs among elderly residents at geriatric homes.Methods:A quasi-experimental design was used to carry out the current study.A purposive sample comprised of all formal(39 nurses)or informal caregivers(39)and all immobilized elderly residents(35)who are found in all geriatric centers in Helwan district.A structured questionnaire was used to assess caregivers’socio-demographic characteristics,knowledge,attitude,and observational checklists for their practice for prevention of PU at pre-and posttest and during follow-up.Results:After the training program,there were improvements in the level of knowledge,practice,and positive attitude of caregivers about PU prevention with a statistically significant difference between pre-,post-,and follow-up training programs(P<0.001).Conclusions:The study revealed that the training program seemed to change the knowledge,practice,and attitude of the subjects to PU prevention.This,in turn,implies that adequate knowledge affects directly the elderly caregivers’attitudes as well as practice for prevention could be important in reducing the burden of PU among the elderly.Thus,conducting a training program for caregivers at different geriatric homes about caring skills for elders can prevent PU,and using spontaneous reposition is very effective to prevent PUs.展开更多
Accurate gas viscosity determination is an important issue in the oil and gas industries.Experimental approaches for gas viscosity measurement are timeconsuming,expensive and hardly possible at high pressures and high...Accurate gas viscosity determination is an important issue in the oil and gas industries.Experimental approaches for gas viscosity measurement are timeconsuming,expensive and hardly possible at high pressures and high temperatures(HPHT).In this study,a number of correlations were developed to estimate gas viscosity by the use of group method of data handling(GMDH)type neural network and gene expression programming(GEP)techniques using a large data set containing more than 3000 experimental data points for methane,nitrogen,and hydrocarbon gas mixtures.It is worth mentioning that unlike many of viscosity correlations,the proposed ones in this study could compute gas viscosity at pressures ranging between 34 and 172 MPa and temperatures between 310 and 1300 K.Also,a comparison was performed between the results of these established models and the results of ten wellknown models reported in the literature.Average absolute relative errors of GMDH models were obtained 4.23%,0.64%,and 0.61%for hydrocarbon gas mixtures,methane,and nitrogen,respectively.In addition,graphical analyses indicate that the GMDH can predict gas viscosity with higher accuracy than GEP at HPHT conditions.Also,using leverage technique,valid,suspected and outlier data points were determined.Finally,trends of gas viscosity models at different conditions were evaluated.展开更多
背景如何保证呼吸科重症监护室(intensive care unit,ICU)患者肠内营养治疗安全性及有效性成为研究热点.胃残余量为肠内营养重要评估指标,可指导后续干预但近年来临床对胃残余量的评估准确性、科学性存在一定争议.目的探讨腹内压联合24 ...背景如何保证呼吸科重症监护室(intensive care unit,ICU)患者肠内营养治疗安全性及有效性成为研究热点.胃残余量为肠内营养重要评估指标,可指导后续干预但近年来临床对胃残余量的评估准确性、科学性存在一定争议.目的探讨腹内压联合24 h胃残余量监测调适的肠内营养方案在呼吸科ICU鼻饲患者中的应用效果.方法选取2019-02/2020-12我院呼吸科ICU鼻饲患者82例,依据随机数字表法分为研究组(n=41)及对照组(n=41).对照组采取常规营养支持,研究组采取腹内压联合24 h胃残余量监测调适的肠内营养方案干预.统计两组治疗情况、干预前后营养状态指标[转铁蛋白(transferrin,TF)、前白蛋白(prealbumin,PA)、白蛋白(albumin,ALB)]水平、T细胞亚群指标(CD3^(+)、CD4^(+)、CD4^(+)/CD8^(+))水平、不良事件发生情况.结果(1)研究组达目标喂养用时、ICU住院时间短于对照组(P<0.05);(2)干预后两组TF、PA、ALB水平较干预前增高(P<0.05),但研究组干预后TF、PA、ALB水平虽略高于对照组,但二者比较无显著差异;(3)两组CD3^(+)、CD4^(+)、CD4^(+)/CD8^(+)干预后水平增高(P<0.05),但研究组干预后CD3^(+)、CD4^(+)、CD4^(+)/CD8^(+)水平虽略高于对照组,但二者比较无显著差异;(4)研究组营养达标率较对照组高,营养支持中断发生率较对照组低(P<0.05);(5)研究组腹胀、呕吐的发生率(4.88%)明显低于对照组(21.95%)(P<0.05).但两组吸入性肺炎及腹泻的发生率比较无显著差异.结论腹内压联合24 h胃残余量监测调适的肠内营养方案在呼吸科ICU鼻饲患者中具有较高应用价值,可改善患者机体营养状态及免疫功能,提高生存质量,减少不良事件发生.展开更多
Good practices of maintenance optimization in nuclear power field need to be effectively consolidated and inherited,and maintenance optimization can provide technology support to create a long-term reliable and econom...Good practices of maintenance optimization in nuclear power field need to be effectively consolidated and inherited,and maintenance optimization can provide technology support to create a long-term reliable and economic operation for nuclear power plants( NPPs) especially for a large number of nuclear powers under construction. Based on the development and application of maintenance template in developed countries,and combining with reliability-centered maintenance( RCM) analysis results and maintenance experience data over the past ten years in domestic NPPs, the development process of maintenance template was presented for Chinese pressurized water reactor( PWR) NPP,and the application of maintenance template to maintenance program development and maintenance optimization combined with cases were demonstrated. A shortcut was provided for improving the efficiency of maintenance optimization in domestic PWR NPP,and help to realize a safe,reliable,and economic operation for domestic NPPs.展开更多
Objectives Most medical instruments are designed for diagnosis purpose but very few for clinical treatment. Our research aim is to design and develop a cardiovascular automatic feedback control instrument （CAFCI） fo...Objectives Most medical instruments are designed for diagnosis purpose but very few for clinical treatment. Our research aim is to design and develop a cardiovascular automatic feedback control instrument （CAFCI） for rescuing the critical patients with abnormal blood pressure. Methods The CAFCI was designed on the basis of abundant clinical experiences and on successful mathematic modeling of our blood pressure, pulmonary experimental data. The capillary wedge pressure, and rates of heart beat were measured and inputted into a computer and drugs were chosen by a doctor through a user-friendly interface with the computer. The responses to medication were rapidly acquired and feed back to the computer by automatic detection system in a close-loop system. every 7.5 sec in order to dosage The data were refreshed regulate the speed and of the medications that were given. Results The experimental results with ten dogs showed that the CAFCI system took samples promptly and accurately so that the targeted blood pressure could be reached reliably based on our input parameters and our designing requirements. Conclusions Since the dependability and accuracy of the CAFCI system are much superior to that of the traditional method, its clinical application to rescue the critical patient warrants evaluation in the future.展开更多
A class of closed-loop supply chain system consisting of one manufacturer and one supplier is designed, in which re-distribution, remanufacturing and reuse are considered synthetically. The manufacturer is in charge o...A class of closed-loop supply chain system consisting of one manufacturer and one supplier is designed, in which re-distribution, remanufacturing and reuse are considered synthetically. The manufacturer is in charge of recollecting and re-disposal the used products. Demands of ultimate products and collecting quantity of used products are described as the function of prices and reference prices. A non-linear dynamic pricing model for this closed-loop supply chain is established. A numerical example is designed, and the results of this example verified the model’s validity to price for the operation of closed-loop supply chain system.展开更多
This paper investigates and analyzes the current situation of young teachers in ten universities in Shaanxi via questionnaire survey and random interview. It is shown that the main source of pressure include the follo...This paper investigates and analyzes the current situation of young teachers in ten universities in Shaanxi via questionnaire survey and random interview. It is shown that the main source of pressure include the following aspects ： heavy burden of education and research, high-pressure in economy and life, high expectations of personal development, lack of physical exercise, mechanization of college evaluation system. On the basis of the above analysis, this paper puts forward the specific EAP model which is suitable to young teachers in NWPU Furtherly, the program impact assessment method is constructed to ensure the effective implementation of the program展开更多
文摘A computer program PRETTA “Pressurizer Transient Thermodynamics Analysis” was developed for the prediction of pressurizer under transient conditions. It is based on the solution of the conservation laws of heat and mass applied to the three separate and non equilibrium thermodynamic regions. In the program all of the important thermal-hydraulics phenomena occurring in the pressurizer: stratification of the hot water and incoming cold water, bulk flashing and condensation, wall condensation, and interfacial heat and mass transfer have been considered. The bubble rising and rain-out models are developed to describe bulk flashing and condensation, respectively. To obtain the wall condensation rate, a one-dimensional heat conduction equation is solved by the pivoting method. The presented computer program will predict the pressure-time behavior of a PWR pressurizer during a variety of transients. The results obtained from the proposed mathematical model are in good agreement with available data on the CHASHMA nuclear power plant's pressurizer performance.
文摘A type of single neuron adaptive PID regulator with auto-tuning gain is proposed and applied to the work control of fans, waterpumps and air-pressers etc. in Handan Iron & Steel Compel China. The robusthess of induStrial parameter closed-loop process controlsystems is improved, and the work quality of the systems bettered.
文摘Objectives:Pressure ulcer(PU)is one of the most common problem among the bedridden elderly and has significantly more burden on elderly and caregivers.This study is aimed to evaluate the effects of the training program for caregivers to prevent PUs among elderly residents at geriatric homes.Methods:A quasi-experimental design was used to carry out the current study.A purposive sample comprised of all formal(39 nurses)or informal caregivers(39)and all immobilized elderly residents(35)who are found in all geriatric centers in Helwan district.A structured questionnaire was used to assess caregivers’socio-demographic characteristics,knowledge,attitude,and observational checklists for their practice for prevention of PU at pre-and posttest and during follow-up.Results:After the training program,there were improvements in the level of knowledge,practice,and positive attitude of caregivers about PU prevention with a statistically significant difference between pre-,post-,and follow-up training programs(P<0.001).Conclusions:The study revealed that the training program seemed to change the knowledge,practice,and attitude of the subjects to PU prevention.This,in turn,implies that adequate knowledge affects directly the elderly caregivers’attitudes as well as practice for prevention could be important in reducing the burden of PU among the elderly.Thus,conducting a training program for caregivers at different geriatric homes about caring skills for elders can prevent PU,and using spontaneous reposition is very effective to prevent PUs.
文摘Accurate gas viscosity determination is an important issue in the oil and gas industries.Experimental approaches for gas viscosity measurement are timeconsuming,expensive and hardly possible at high pressures and high temperatures(HPHT).In this study,a number of correlations were developed to estimate gas viscosity by the use of group method of data handling(GMDH)type neural network and gene expression programming(GEP)techniques using a large data set containing more than 3000 experimental data points for methane,nitrogen,and hydrocarbon gas mixtures.It is worth mentioning that unlike many of viscosity correlations,the proposed ones in this study could compute gas viscosity at pressures ranging between 34 and 172 MPa and temperatures between 310 and 1300 K.Also,a comparison was performed between the results of these established models and the results of ten wellknown models reported in the literature.Average absolute relative errors of GMDH models were obtained 4.23%,0.64%,and 0.61%for hydrocarbon gas mixtures,methane,and nitrogen,respectively.In addition,graphical analyses indicate that the GMDH can predict gas viscosity with higher accuracy than GEP at HPHT conditions.Also,using leverage technique,valid,suspected and outlier data points were determined.Finally,trends of gas viscosity models at different conditions were evaluated.
文摘Good practices of maintenance optimization in nuclear power field need to be effectively consolidated and inherited,and maintenance optimization can provide technology support to create a long-term reliable and economic operation for nuclear power plants( NPPs) especially for a large number of nuclear powers under construction. Based on the development and application of maintenance template in developed countries,and combining with reliability-centered maintenance( RCM) analysis results and maintenance experience data over the past ten years in domestic NPPs, the development process of maintenance template was presented for Chinese pressurized water reactor( PWR) NPP,and the application of maintenance template to maintenance program development and maintenance optimization combined with cases were demonstrated. A shortcut was provided for improving the efficiency of maintenance optimization in domestic PWR NPP,and help to realize a safe,reliable,and economic operation for domestic NPPs.
文摘Objectives Most medical instruments are designed for diagnosis purpose but very few for clinical treatment. Our research aim is to design and develop a cardiovascular automatic feedback control instrument （CAFCI） for rescuing the critical patients with abnormal blood pressure. Methods The CAFCI was designed on the basis of abundant clinical experiences and on successful mathematic modeling of our blood pressure, pulmonary experimental data. The capillary wedge pressure, and rates of heart beat were measured and inputted into a computer and drugs were chosen by a doctor through a user-friendly interface with the computer. The responses to medication were rapidly acquired and feed back to the computer by automatic detection system in a close-loop system. every 7.5 sec in order to dosage The data were refreshed regulate the speed and of the medications that were given. Results The experimental results with ten dogs showed that the CAFCI system took samples promptly and accurately so that the targeted blood pressure could be reached reliably based on our input parameters and our designing requirements. Conclusions Since the dependability and accuracy of the CAFCI system are much superior to that of the traditional method, its clinical application to rescue the critical patient warrants evaluation in the future.
文摘A class of closed-loop supply chain system consisting of one manufacturer and one supplier is designed, in which re-distribution, remanufacturing and reuse are considered synthetically. The manufacturer is in charge of recollecting and re-disposal the used products. Demands of ultimate products and collecting quantity of used products are described as the function of prices and reference prices. A non-linear dynamic pricing model for this closed-loop supply chain is established. A numerical example is designed, and the results of this example verified the model’s validity to price for the operation of closed-loop supply chain system.
基金fund by High Education Research Fund of Northwestern Polytechnical University(2014)
文摘This paper investigates and analyzes the current situation of young teachers in ten universities in Shaanxi via questionnaire survey and random interview. It is shown that the main source of pressure include the following aspects ： heavy burden of education and research, high-pressure in economy and life, high expectations of personal development, lack of physical exercise, mechanization of college evaluation system. On the basis of the above analysis, this paper puts forward the specific EAP model which is suitable to young teachers in NWPU Furtherly, the program impact assessment method is constructed to ensure the effective implementation of the program
