The intercritical heat-affected zone（ICHAZ） of X80 pipeline steel was simulated by using the Gleeble-3500thermal/mechanical simulator according to the thermal cycle of in-service welding.The microstructures of ICHAZ...The intercritical heat-affected zone（ICHAZ） of X80 pipeline steel was simulated by using the Gleeble-3500thermal/mechanical simulator according to the thermal cycle of in-service welding.The microstructures of ICHAZ with different cooling rates were examined,and the hardness,the toughness and corresponding fractography were investigated.Results show that untransformed bainite and ferrite as well as retransformed fine bainite and martensite–austenite（M–A）constituents constitute the microstructure of ICHAZ.The two different morphologies of M–A constituents are stringer and block.Second phase particles which mainly composed of Ti,Nb,C,Fe and Cu coarsened in ICHAZ.Compared with normal welding condition,the toughness of ICHAZ is poor when the cooling time is short under in-service welding condition because of the large area fraction and size of M–A constituents that connect into chains and distribute at the grain boundaries.The Vickers hardness of ICHAZ that decreases with the increase in the cooling time is independent with the area fraction of M–A constituents.展开更多
Some research results are given in this paper about burnthrough and hydrogen cracking with a flowing chamber and a loop. Many factors including plate thickness, running rate, heat input and so forth have been studied....Some research results are given in this paper about burnthrough and hydrogen cracking with a flowing chamber and a loop. Many factors including plate thickness, running rate, heat input and so forth have been studied. By experiments it can be found that occurrence of hydrogen cracking can be effectively reduced by properly increasing heat input and using the tempering bead technique.展开更多
Hydrogen induced cracking （HIC） is one of the main problems of in-service welding onto active pipeline. Microstructure and hardness of welded joint have a vital effect on hydrogen induced cracking. The microstructur...Hydrogen induced cracking （HIC） is one of the main problems of in-service welding onto active pipeline. Microstructure and hardness of welded joint have a vital effect on hydrogen induced cracking. The microstructure and hardness of welded joint of XTO pipeline steel were studied using simulation in-service welding device. The results show that the main microstructures of in-service welded seam are grain boundary ferrite , intracrystalline acicular ferrite , as well as small amount of widmanztatten structure. The main microstructures of coarse grain heat-affected zone （CGHAZ） are coarse granular bainite, lath ferrite and martensite. Metastable phases such as martensite and lath ferrite are found in CGHAZ because of the too quick cooling velocity a＇nd the hardness of the CGHAZ is high.展开更多
The special subject 'research on life prediction technology of important in-service pressure' mainly analyzes the failure mechanism of large-sized important and criticalin-service pressure vessels under the ac...The special subject 'research on life prediction technology of important in-service pressure' mainly analyzes the failure mechanism of large-sized important and criticalin-service pressure vessels under the action of working medium and investigates safety assessmentand life prediction technology with a view to enhance the operation reliability of in-servicepressure vessels in China. Based on a series of accident investigation and test & measuringresearch, the cause of cracking of catalytic regenerator is analyzed and the in-line non-destructiveexamination method and failure prevention measures for the cracking of catalytic regenerator areproposed.展开更多
Elbows are the most vulnerable parts in pipeline network systems. The residual stress for in-service welding repair has significant impacts on the mechanical properties of straight pipes and elbows. In this paper,the ...Elbows are the most vulnerable parts in pipeline network systems. The residual stress for in-service welding repair has significant impacts on the mechanical properties of straight pipes and elbows. In this paper,the thermal elastic-plastic finite element method is employed to investigate the mechanical field during the in-service welding. The prediction of residual stress and deformation in the straight pipe and elbow is performed based on the validation of the numerical models. And the effects of the curvature radius and defects on the elbow are investigated. The results show that the residual stress distribution is uneven along various directions after welding. And the mechanical properties of the elbow decrease when the curvature radius is small. Compared to the intact elbow,the residual stress of the elbow with defects concentrates in the defective area. The depth of defect is the main factors affecting the mechanical properties of the elbow. A systematic analysis of the mechanical properties of straight pipes and elbows is proposed to provide guidance to the in-service welding.展开更多
The chamber device was designed and set up to simulate the in-service welding. The results show ： the t8/5 , t8/3 and inner wall peak temperature Tp decrease with the cooling rate increases. The welding energy is car...The chamber device was designed and set up to simulate the in-service welding. The results show ： the t8/5 , t8/3 and inner wall peak temperature Tp decrease with the cooling rate increases. The welding energy is carried off by flowing medium, the cooling rate increases, and many unbalanced microstructures such as granular bainite, martensite and M-A generate ; it worsens the properties of HAZ. Under air-cooling, the cooling rate is slow, the austenite grain grows obviously, the lath ferrite crosses the whole austenite, and it causes the hardness value is also big. The change of HAZ width is not obvious with the increase of cooling rate; and burn-through is not susceptible to the cooling rate. The quench microstructures increase and the hydrogen does not outflow from the HAZ easily when increase the cooling rate, so the susceptibility of hydrogen cracking increases.展开更多
Petrochemical storage tanks are generally inspected when the tank is offline mostly to assess the extent of underside corrosion on the tank floor. Emptying, cleaning and opening a tank for inspection take many months ...Petrochemical storage tanks are generally inspected when the tank is offline mostly to assess the extent of underside corrosion on the tank floor. Emptying, cleaning and opening a tank for inspection take many months and are very expensive. Inspection costs can be reduced significantly by inserting robots through manholes on the tank roof to pertbrm non-destructive testing （NDT）. The challenge is to develop robots that can operate safely in explosive and hazardous environments and measure the thickness of floor plates using ultrasound sensors. This paper reports on the development of a small and inexpensive prototype robot （NDTBOT） which is designed to be intrinsically safe for zone zero operation. The robot ＂hops＂ across the floor to make measurements, without any external moving parts. The paper describes the design, experimental testing of the NDTBOT and presents results of steel plate thickness measurements made under water.展开更多
Aiming at the information evaluation of traffic infrastructure in-service roadside slope risk assessment,the method of risk assessment for highway slope engineering is proposed by using the combination of quantitative...Aiming at the information evaluation of traffic infrastructure in-service roadside slope risk assessment,the method of risk assessment for highway slope engineering is proposed by using the combination of quantitative and qualitative methods,and a new risk assessment method is proposed and improved.The system,in order to prevent the risks in slope engineering,serves the scientific decision-making of the maintenance,operation and management of the in-service road slopes.Based on the analysis of the special geological conditions,complex surrounding environment and construction schemes of existing highway slopes in China,this paper establishes an in-service slope evaluation model for in-service roads,and designs the scheme diagram of the in-service road slope evaluation system based on the networked Internet platform.Moreover,a set of in-service roadside slope risk assessment system software,the system component block diagram and the main design interface are given.This system can meet the needs of comprehensive evaluation of multi-factors in service road slopes.展开更多
SYSWELD was used to simulate in-service welding process of gas pipeline of X70 pipeline steel. Welding thermal cycle, stress and deformation of in-service welded joint were studied. The results show that peak temperat...SYSWELD was used to simulate in-service welding process of gas pipeline of X70 pipeline steel. Welding thermal cycle, stress and deformation of in-service welded joint were studied. The results show that peak temperature of coarse grain heat-affected zone （CGHAZ） of in-service welding onto gas pipeline is the same with routine welding, but ts/5, ts/3 and ts/1 decrease at certain degree. For the zone near welded seam, axial stress and hoop stress in the inner pipe wall are compressive stress when welding source passes through the cross-section that is studied, but residual axial stress and residual hoop stress after welded are all tensile stress. Transient deformation and residual deformation are all convex deformation compared with the original pipe diameter size. Deformation achieves maximum when welding thermal source passes through the cross-section that is studied and then decreases during the cooling process after welding.展开更多
The software of SYSWELD was used to build model and simulate thermal cycle of in-service welding onto active gas pipeline. Influence of pipe diameter, wall thickness and heat input on thermal cycle was studied. The re...The software of SYSWELD was used to build model and simulate thermal cycle of in-service welding onto active gas pipeline. Influence of pipe diameter, wall thickness and heat input on thermal cycle was studied. The results show that t8/5 , t8/3 and peak temperature of inner surface decrease when wall thickness increases from 5 mm to 12 mm. But t8/1 will increases with the increase of wall thickness and will decrease after the wall thickness is larger than 7 mm. Pipe diameter has little influence on thermal cycle and that influence can be ignored when pipe diameter is greater than 273 mm. t8/5 , t8/3 , t8/1 and peak temperature of inner surface will increase with the increase of heat input.展开更多
Malaria is generally considered a major public health problem in Somalia. Providing early diagnosis and effective treatment is the key element of malaria control strategies in malaria-endemic countries, including Soma...Malaria is generally considered a major public health problem in Somalia. Providing early diagnosis and effective treatment is the key element of malaria control strategies in malaria-endemic countries, including Somalia. This required to advocate and ensure health worker’s adherence to the national malaria guidelines at all levels of health care service. A well-designed in-service training program may improve the level of health worker’s adherence to national malaria treatment guidelines, although results have been inconsistent. This is an interventional health facility-based pre and post comparative study aimed to assess the effect of an in-service training program on the practice of healthcare workers toward malaria prevention and treatment guidelines, during in pregnancy in health facilities in Jowhar district, Middle Shabelle region of Somalia. The study was implemented in three phases: pre-intervention phase, intervention phase and post-intervention phase. The sample size consisted of (n = 150) health workers who were selected from ten public health facilities using proportional to size sampling;the data collection adopted in this research is composed of a structured interview questionnaire and observational checklist. Data was analyzed through the application of descriptive statistical analysis that includes frequency and percentage and the Chi-square (x<sup>2</sup>) test was used to test the associations among variables using SPSS software version 25. The study showed that the level of health workers’ awareness of the national malaria guidelines in the treatment and prevention of malaria in pregnancy was found to be good before the intervention 89 (59.3%) and this proportion increased to 150 (100%) post-intervention of the training program. A significance difference has been observed between health workers’ awareness and their adherence to the malarial guidelines at pre-test and post-test with a p-value 0.000. The proportion of health workers who attended previous training on national malaria guidelines in the treatment and prevention of malaria in pregnancy increased from 46 (30.7%) at the pre-test to 150 (100%) after the post-test. A significant difference was observed in the training status among different categories of health worker and their adherence to the guidelines during the pre- and post-intervention of the training program, with a p-value of 0.000. The result showed that health workers were adhering to the guidelines at the pre-test 33 (22%), this increased after the post-test to 87 (58%). The knowledge of the need to adhere led to an increase in the adherence rate after the training program intervention. The study reveals that inadequate awareness was most reason for the non-adherence in the majority of the health workers as indicated by 89 (59.3%) at the pre-test and 56 (37.3%) in the post-test. However, difference was not significant between the availability of anti-malaria drugs in the facilities and the health workers’ adherence to the guidelines p-value 0.355 at the pretest and p-value 0.258 at post-test. The study concluded that the in-service training program significantly improved health workers’ knowledge and practice to the national malaria guidelines in the treatment, and prevention of malaria in pregnancy. The researcher recommends that the national malaria control programme (NMCP) of the Federal Ministry of Health should provide continuous regular in-service training to frontline healthcare workers at (facility and Community-based) to upgrade their skills and knowledge towards the malaria guidelines, disseminate job aids to the health facilities and undertake regular monitoring to ensure effective implementation of the national malaria treatment guidelines in the treatment and prevention of malaria in pregnancy in achieving desired proper case-management practices of malaria in pregnancy at all levels of health care service.展开更多
Objective: To investigate and analyze the current status of continuing nursing education (CNE) of in-service nurses in Tibet and their demand for continuing education. Methods: 663 active nurses in Tibet were taken as...Objective: To investigate and analyze the current status of continuing nursing education (CNE) of in-service nurses in Tibet and their demand for continuing education. Methods: 663 active nurses in Tibet were taken as the research objects, and the self-developed questionnaire was used to investigate the current status and needs of CNE, and the correlation between the CNE needs of active nurses and their personal conditions was analyzed. Results: This study shows that 65.61% (435/663) of active nurses have not participated in any CNE, and 91.86% (609/663) of active nurses believe that they need to participate in CNE. The problems faced by active nurses in participating in CNE include funding restrictions, time limitation and ability limitation. Logistic stepwise regression analysis reveals that the age of active nurses and working years of nurses are negatively correlated with the funding restrictions for participating in CNE (P < 0.05). It is relatively more difficult for young nurses with less working experience to obtain funding for participating in CNE. Moreover, there is a negative correlation between age, educational level and the ability of nurses to participate in CNE (P < 0.05). Younger nurses with lower educational level are more difficult to participate in CNE due to personal ability. There is a positive correlation between the length of working experience and the time limitation faced to participate in CNE (P < 0.05). Senior nurses are too busy with their work to participate in CNE due to limited time. Conclusion: The problems faced by active nurses in Tibet in participating in CNE come from funding, time and ability. Young nurses with limited working experience cannot participate in CNE resulting from limited ability and funds;while senior nurses are mainly restricted by time. It is recommended that hospitals and nursing management in Tibet should solve these problems faced by nurses in participating in CNE by implementing a flexible scheduling system, and providing funding or implementing an incentive system, to enhance the confidence of active nurses in participating in CNE.展开更多
In-service structural health monitoring（SHM） technologies are critical for the utilization of composite aircraft structures. We developed a Lamb wave-based in-service SHM technology using built-in piezoelectric actu...In-service structural health monitoring（SHM） technologies are critical for the utilization of composite aircraft structures. We developed a Lamb wave-based in-service SHM technology using built-in piezoelectric actuator/sensor networks to monitor delamination extension in a full-scale composite horizontal tail. The in-service SHM technology combine of damage rapid monitoring（DRM） stage and damage imaging diagnosis（DID） stage allows for real-time monitoring and long term tracking of the structural integrity of composite aircraft structures. DRM stage using spearman rank correlation coeffi cient was introduced to generate a damage index which can be used to monitor the trend of damage extension. The DID stage based on canonical correlation analysis aimed at intuitively highlighting structural damage regions in two-dimensional images. The DRM and DID stages were trialed by an in-service SHM experiment of CFRP T-joint. Finally, the detection capability of the in-service SHM technology was verified in the SHM experiment of a full-scale composite horizontal tail. Experimental results show that the rapid monitoring method effectively monitors the damage occurrence and extension tendency in real time; damage imaging diagnosis results are consistent with those from the failure model of the composite horizontal tail structure.展开更多
Purpose:This study aims to investigate the noticing ability of Chinese in-service mathematics tea-chers(ISTs)when observing exemplary mathematics lessons online using two different noticing frameworks.Design/Approach/...Purpose:This study aims to investigate the noticing ability of Chinese in-service mathematics tea-chers(ISTs)when observing exemplary mathematics lessons online using two different noticing frameworks.Design/Approach/Methods:The noticing of 24 ISTs was examined based on three dimensions:agent,topic,and stance.The data were collected qualitatively through guided questions during the video observation activity,and their noticing levels were analyzed using existing frameworks.Findings:Utilizing the Focused Framework,Chinese ISTs exhibited a greater breadth and depth of noticing,in relation to both students'mathematical thinking and teaching pedagogies.Their noticing abilities surpassed those utilizing an Open Framework,with enhanced sensitivity in adapting their teaching strategies to better address students'mathematical reasoning,The study also revealed limitations in the current practices of classroom observation and teacher reflections.OriginalitylValue:This study provides valuable insights into the noticing abilities of Chinese inservice teachers and the effectiveness of various noticing frameworks in enhancing their skills.It highlights the importance of further research on teacher noticing within Eastern contexts.The findings have significant implications for teachers'professional development,advocating for the integration of noticing frameworks into teacher education programs to improve teachers'abilities to discern critical elements of students'mathematical thinking and pedagogical practices.展开更多
This study explores the feasibility of electromagnetic acoustic transducers(EMATs)for ultrasonic rail inspection,focusing on bulk wave generation from the rail head and on defect detection at the central part of the r...This study explores the feasibility of electromagnetic acoustic transducers(EMATs)for ultrasonic rail inspection,focusing on bulk wave generation from the rail head and on defect detection at the central part of the rail foot.As a contactless method,EMATs could overcome some known limitations of conventional ultrasonic techniques,but require further validation.Differ-ent campaigns of experimental tests were performed,evaluating,by means of a probability of detection approach,the response of the technique to several artificial semi-elliptical flaws of increasing size and by considering two sensors characterized by different working frequencies.In contact,static tests allowed to assess the basic feasibility of the inspection technique and showed a linear response to defect size,saturating when defect width exceeded the rail web thickness.Dynamic tests allowed to introduce the effects of lift-off on signal responses.During all tests,the higher-frequency sensor outperformed the lower-frequency one.Finally,full-scale bogie tests on an indoor permanent track installation,comprehensive of defec-tive rails,confirmed the higher flaw detection rates of the higher-frequency sensor,with minimal detection failures despite occasional false alarms.EMATs showed encouraging results for in-motion rail inspection:with further technical development and optimization,this technique could enhance ultrasonic rail inspection by diagnostic trains.展开更多
A method of predicting design pressure and burn-through of in-service welding pipes was established. Temperature distributions of in-service welding under variable parameters were simulated by FEM. The effect of flowi...A method of predicting design pressure and burn-through of in-service welding pipes was established. Temperature distributions of in-service welding under variable parameters were simulated by FEM. The effect of flowing of internal media was regarded as forced convection. Based on the numerical results, design pressure of the pipe can be obtained and burn-through can be predicted. It can be concluded that the design pressure decreases with the increasing of heat input. RSF and design pressure of the pipe increase with the increasing of flow rate. There is a range in which the increase changes greatly. For in-service welding, the range should be considered adequately to determine operating condition optimally. RSF increases with the increasing of pipe wall thickness. While the thickness increases to an extent, RSF shows little increase. Accord- ing to the curves of design pressure versus different parameters, safe working pressure can be achieved.展开更多
Purpose:This paper aims to examine the participation experiences of a sample of Chinese teacher trainees and their Finnish teacher trainer on an in-service teacher training program exported from Finland to Beijing,Chi...Purpose:This paper aims to examine the participation experiences of a sample of Chinese teacher trainees and their Finnish teacher trainer on an in-service teacher training program exported from Finland to Beijing,China.Design/Approach/Methods:Six science teachers from Beijing and their Finnish teacher trainer participated in semi-structured interviews.From the ideological perspective of international education,a total of eight semi-structured interviews were analyzed through qualitative content analysis.Findings:The results show that all interviewees were highly motivated to learn from the Other's education system and culture.Some participants benefited from a broader understanding of the Self's and the Other's education systems,while others did not.The interviewees also described some participation challenges,such as language barriers and practices that adapted learner-centered teaching approaches in Beijing schools.Furthermore,the interviewees mentioned future expectations of more in-depth communication between Finland and China.Originality/Value:Some recommendations for better training outcomes,improving the quality of participation experiences,and reaching more mutual understandings were discussed at the end of this study.展开更多
Objective:The objective of this study is to develop and evaluate a structured clinical rotation-based emergency response training program to enhance nurses’emergency competence,theoretical knowledge,and technical ski...Objective:The objective of this study is to develop and evaluate a structured clinical rotation-based emergency response training program to enhance nurses’emergency competence,theoretical knowledge,and technical skills.Methods:A comprehensive emergency training program was developed,and a randomized controlled trial was implemented from June 2022 to May 2023 at a tertiary general hospital in Chongqing,China.The study involved 214 nurses,with 106 participants in the intervention group receiving a 3-month innovative emergency response competence training and 108 in the control group undergoing conventional training.Postintervention assessments evaluated emergency response capabilities using the Emergency Response Ability Assessment Scale for Nurses in Public Health Emergencies,theoretical knowledge through a self-designed comprehensive theoretical assessment instrument,technical skills using a standardized skill assessment form,and training satisfaction through two distinct feedback instruments.Results:The emergency response ability scores were significantly higher in the intervention group compared to controls(3.99±0.18 vs.2.53±0.25,P<0.05).Theoretical assessment scores showed marked improvement in the intervention group versus the control group(85.31±4.40 vs.52.45±6.19,P<0.05).Technical skill performance was significantly better in the intervention group than that in controls(94.47±1.64 vs.86.39±2.36,P<0.05).Training satisfaction was higher among intervention group nurses compared to controls(4.53±0.23 vs.4.00±0.38,P<0.05),with nursing managers also reporting greater satisfaction with the intervention program versus conventional training(4.57±0.49 vs.3.92±0.79,P<0.05).Conclusion:The clinical rotation-based structured emergency response training program effectively enhances nurses’emergency competencies,theoretical knowledge,and technical skills.These findings provide both theoretical foundations and practical guidelines for developing emergency response and specialized nursing competence training programs.展开更多
基金supported by Key Project of Tianjin Municipal Science and Technology Support Program (No.11ZCGYSF00100)Tianjin Natural Science Foundation (No.11JCYBJC06000)the Gansu province Science and Technology Support Program (No.1204GKCA007)
文摘The intercritical heat-affected zone（ICHAZ） of X80 pipeline steel was simulated by using the Gleeble-3500thermal/mechanical simulator according to the thermal cycle of in-service welding.The microstructures of ICHAZ with different cooling rates were examined,and the hardness,the toughness and corresponding fractography were investigated.Results show that untransformed bainite and ferrite as well as retransformed fine bainite and martensite–austenite（M–A）constituents constitute the microstructure of ICHAZ.The two different morphologies of M–A constituents are stringer and block.Second phase particles which mainly composed of Ti,Nb,C,Fe and Cu coarsened in ICHAZ.Compared with normal welding condition,the toughness of ICHAZ is poor when the cooling time is short under in-service welding condition because of the large area fraction and size of M–A constituents that connect into chains and distribute at the grain boundaries.The Vickers hardness of ICHAZ that decreases with the increase in the cooling time is independent with the area fraction of M–A constituents.
文摘Some research results are given in this paper about burnthrough and hydrogen cracking with a flowing chamber and a loop. Many factors including plate thickness, running rate, heat input and so forth have been studied. By experiments it can be found that occurrence of hydrogen cracking can be effectively reduced by properly increasing heat input and using the tempering bead technique.
文摘Hydrogen induced cracking （HIC） is one of the main problems of in-service welding onto active pipeline. Microstructure and hardness of welded joint have a vital effect on hydrogen induced cracking. The microstructure and hardness of welded joint of XTO pipeline steel were studied using simulation in-service welding device. The results show that the main microstructures of in-service welded seam are grain boundary ferrite , intracrystalline acicular ferrite , as well as small amount of widmanztatten structure. The main microstructures of coarse grain heat-affected zone （CGHAZ） are coarse granular bainite, lath ferrite and martensite. Metastable phases such as martensite and lath ferrite are found in CGHAZ because of the too quick cooling velocity a＇nd the hardness of the CGHAZ is high.
基金important scientech problemtackling subject foundation under the state 9th 5-year plan(no.96-918-02-04).
文摘The special subject 'research on life prediction technology of important in-service pressure' mainly analyzes the failure mechanism of large-sized important and criticalin-service pressure vessels under the action of working medium and investigates safety assessmentand life prediction technology with a view to enhance the operation reliability of in-servicepressure vessels in China. Based on a series of accident investigation and test & measuringresearch, the cause of cracking of catalytic regenerator is analyzed and the in-line non-destructiveexamination method and failure prevention measures for the cracking of catalytic regenerator areproposed.
基金supported by the Natural Science Foundation of Shandong Province(No.ZR2018MEE012)China University of Petroleum(East China)Graduate Innovation Project(No.YCX2017052)
文摘Elbows are the most vulnerable parts in pipeline network systems. The residual stress for in-service welding repair has significant impacts on the mechanical properties of straight pipes and elbows. In this paper,the thermal elastic-plastic finite element method is employed to investigate the mechanical field during the in-service welding. The prediction of residual stress and deformation in the straight pipe and elbow is performed based on the validation of the numerical models. And the effects of the curvature radius and defects on the elbow are investigated. The results show that the residual stress distribution is uneven along various directions after welding. And the mechanical properties of the elbow decrease when the curvature radius is small. Compared to the intact elbow,the residual stress of the elbow with defects concentrates in the defective area. The depth of defect is the main factors affecting the mechanical properties of the elbow. A systematic analysis of the mechanical properties of straight pipes and elbows is proposed to provide guidance to the in-service welding.
文摘The chamber device was designed and set up to simulate the in-service welding. The results show ： the t8/5 , t8/3 and inner wall peak temperature Tp decrease with the cooling rate increases. The welding energy is carried off by flowing medium, the cooling rate increases, and many unbalanced microstructures such as granular bainite, martensite and M-A generate ; it worsens the properties of HAZ. Under air-cooling, the cooling rate is slow, the austenite grain grows obviously, the lath ferrite crosses the whole austenite, and it causes the hardness value is also big. The change of HAZ width is not obvious with the increase of cooling rate; and burn-through is not susceptible to the cooling rate. The quench microstructures increase and the hydrogen does not outflow from the HAZ easily when increase the cooling rate, so the susceptibility of hydrogen cracking increases.
文摘Petrochemical storage tanks are generally inspected when the tank is offline mostly to assess the extent of underside corrosion on the tank floor. Emptying, cleaning and opening a tank for inspection take many months and are very expensive. Inspection costs can be reduced significantly by inserting robots through manholes on the tank roof to pertbrm non-destructive testing （NDT）. The challenge is to develop robots that can operate safely in explosive and hazardous environments and measure the thickness of floor plates using ultrasound sensors. This paper reports on the development of a small and inexpensive prototype robot （NDTBOT） which is designed to be intrinsically safe for zone zero operation. The robot ＂hops＂ across the floor to make measurements, without any external moving parts. The paper describes the design, experimental testing of the NDTBOT and presents results of steel plate thickness measurements made under water.
基金Supported by the China Postdoctoral Science Foundation(2019T120872)Shaanxi Province Postdoctoral Science Fund(2017BSHEDZZ40)+2 种基金the Fundamental Research Funds for the Central Universities,CHD(300102329401,300102329502)the 13th Five-Year Equipment Advanced Research Fund Project(61403120105)Science and Technology Project of Shannxi Provincial Transportation Department(17-16K,17-33T)。
文摘Aiming at the information evaluation of traffic infrastructure in-service roadside slope risk assessment,the method of risk assessment for highway slope engineering is proposed by using the combination of quantitative and qualitative methods,and a new risk assessment method is proposed and improved.The system,in order to prevent the risks in slope engineering,serves the scientific decision-making of the maintenance,operation and management of the in-service road slopes.Based on the analysis of the special geological conditions,complex surrounding environment and construction schemes of existing highway slopes in China,this paper establishes an in-service slope evaluation model for in-service roads,and designs the scheme diagram of the in-service road slope evaluation system based on the networked Internet platform.Moreover,a set of in-service roadside slope risk assessment system software,the system component block diagram and the main design interface are given.This system can meet the needs of comprehensive evaluation of multi-factors in service road slopes.
文摘SYSWELD was used to simulate in-service welding process of gas pipeline of X70 pipeline steel. Welding thermal cycle, stress and deformation of in-service welded joint were studied. The results show that peak temperature of coarse grain heat-affected zone （CGHAZ） of in-service welding onto gas pipeline is the same with routine welding, but ts/5, ts/3 and ts/1 decrease at certain degree. For the zone near welded seam, axial stress and hoop stress in the inner pipe wall are compressive stress when welding source passes through the cross-section that is studied, but residual axial stress and residual hoop stress after welded are all tensile stress. Transient deformation and residual deformation are all convex deformation compared with the original pipe diameter size. Deformation achieves maximum when welding thermal source passes through the cross-section that is studied and then decreases during the cooling process after welding.
基金Sponsored by Scientific Research Fund for Doctors(Y040312)Innovation Fund for Doctors(B2005-3) of China University of Petroleum
文摘The software of SYSWELD was used to build model and simulate thermal cycle of in-service welding onto active gas pipeline. Influence of pipe diameter, wall thickness and heat input on thermal cycle was studied. The results show that t8/5 , t8/3 and peak temperature of inner surface decrease when wall thickness increases from 5 mm to 12 mm. But t8/1 will increases with the increase of wall thickness and will decrease after the wall thickness is larger than 7 mm. Pipe diameter has little influence on thermal cycle and that influence can be ignored when pipe diameter is greater than 273 mm. t8/5 , t8/3 , t8/1 and peak temperature of inner surface will increase with the increase of heat input.
文摘Malaria is generally considered a major public health problem in Somalia. Providing early diagnosis and effective treatment is the key element of malaria control strategies in malaria-endemic countries, including Somalia. This required to advocate and ensure health worker’s adherence to the national malaria guidelines at all levels of health care service. A well-designed in-service training program may improve the level of health worker’s adherence to national malaria treatment guidelines, although results have been inconsistent. This is an interventional health facility-based pre and post comparative study aimed to assess the effect of an in-service training program on the practice of healthcare workers toward malaria prevention and treatment guidelines, during in pregnancy in health facilities in Jowhar district, Middle Shabelle region of Somalia. The study was implemented in three phases: pre-intervention phase, intervention phase and post-intervention phase. The sample size consisted of (n = 150) health workers who were selected from ten public health facilities using proportional to size sampling;the data collection adopted in this research is composed of a structured interview questionnaire and observational checklist. Data was analyzed through the application of descriptive statistical analysis that includes frequency and percentage and the Chi-square (x<sup>2</sup>) test was used to test the associations among variables using SPSS software version 25. The study showed that the level of health workers’ awareness of the national malaria guidelines in the treatment and prevention of malaria in pregnancy was found to be good before the intervention 89 (59.3%) and this proportion increased to 150 (100%) post-intervention of the training program. A significance difference has been observed between health workers’ awareness and their adherence to the malarial guidelines at pre-test and post-test with a p-value 0.000. The proportion of health workers who attended previous training on national malaria guidelines in the treatment and prevention of malaria in pregnancy increased from 46 (30.7%) at the pre-test to 150 (100%) after the post-test. A significant difference was observed in the training status among different categories of health worker and their adherence to the guidelines during the pre- and post-intervention of the training program, with a p-value of 0.000. The result showed that health workers were adhering to the guidelines at the pre-test 33 (22%), this increased after the post-test to 87 (58%). The knowledge of the need to adhere led to an increase in the adherence rate after the training program intervention. The study reveals that inadequate awareness was most reason for the non-adherence in the majority of the health workers as indicated by 89 (59.3%) at the pre-test and 56 (37.3%) in the post-test. However, difference was not significant between the availability of anti-malaria drugs in the facilities and the health workers’ adherence to the guidelines p-value 0.355 at the pretest and p-value 0.258 at post-test. The study concluded that the in-service training program significantly improved health workers’ knowledge and practice to the national malaria guidelines in the treatment, and prevention of malaria in pregnancy. The researcher recommends that the national malaria control programme (NMCP) of the Federal Ministry of Health should provide continuous regular in-service training to frontline healthcare workers at (facility and Community-based) to upgrade their skills and knowledge towards the malaria guidelines, disseminate job aids to the health facilities and undertake regular monitoring to ensure effective implementation of the national malaria treatment guidelines in the treatment and prevention of malaria in pregnancy in achieving desired proper case-management practices of malaria in pregnancy at all levels of health care service.
文摘Objective: To investigate and analyze the current status of continuing nursing education (CNE) of in-service nurses in Tibet and their demand for continuing education. Methods: 663 active nurses in Tibet were taken as the research objects, and the self-developed questionnaire was used to investigate the current status and needs of CNE, and the correlation between the CNE needs of active nurses and their personal conditions was analyzed. Results: This study shows that 65.61% (435/663) of active nurses have not participated in any CNE, and 91.86% (609/663) of active nurses believe that they need to participate in CNE. The problems faced by active nurses in participating in CNE include funding restrictions, time limitation and ability limitation. Logistic stepwise regression analysis reveals that the age of active nurses and working years of nurses are negatively correlated with the funding restrictions for participating in CNE (P < 0.05). It is relatively more difficult for young nurses with less working experience to obtain funding for participating in CNE. Moreover, there is a negative correlation between age, educational level and the ability of nurses to participate in CNE (P < 0.05). Younger nurses with lower educational level are more difficult to participate in CNE due to personal ability. There is a positive correlation between the length of working experience and the time limitation faced to participate in CNE (P < 0.05). Senior nurses are too busy with their work to participate in CNE due to limited time. Conclusion: The problems faced by active nurses in Tibet in participating in CNE come from funding, time and ability. Young nurses with limited working experience cannot participate in CNE resulting from limited ability and funds;while senior nurses are mainly restricted by time. It is recommended that hospitals and nursing management in Tibet should solve these problems faced by nurses in participating in CNE by implementing a flexible scheduling system, and providing funding or implementing an incentive system, to enhance the confidence of active nurses in participating in CNE.
基金Funded by the National Natural Science Foundation of China(Nos.11172053 and 91016024)the New Century Excellent Talents in University(NCET-11-0055)the Fundamental Research Funds for the Central Universities(DUT13ZD(G)06)
文摘In-service structural health monitoring（SHM） technologies are critical for the utilization of composite aircraft structures. We developed a Lamb wave-based in-service SHM technology using built-in piezoelectric actuator/sensor networks to monitor delamination extension in a full-scale composite horizontal tail. The in-service SHM technology combine of damage rapid monitoring（DRM） stage and damage imaging diagnosis（DID） stage allows for real-time monitoring and long term tracking of the structural integrity of composite aircraft structures. DRM stage using spearman rank correlation coeffi cient was introduced to generate a damage index which can be used to monitor the trend of damage extension. The DID stage based on canonical correlation analysis aimed at intuitively highlighting structural damage regions in two-dimensional images. The DRM and DID stages were trialed by an in-service SHM experiment of CFRP T-joint. Finally, the detection capability of the in-service SHM technology was verified in the SHM experiment of a full-scale composite horizontal tail. Experimental results show that the rapid monitoring method effectively monitors the damage occurrence and extension tendency in real time; damage imaging diagnosis results are consistent with those from the failure model of the composite horizontal tail structure.
基金supported by the Seed Fund of the Education University of Hong Kong,Hong Kong SAR(Project No.R4248:RG43/21-22R)partially supported by Departmental Research Grant(Project No.04786)The work was also partially supported by the Guangdong Province General Universities Young Innovative Talents Category Project(Ref.2023 WQNCX076).
文摘Purpose:This study aims to investigate the noticing ability of Chinese in-service mathematics tea-chers(ISTs)when observing exemplary mathematics lessons online using two different noticing frameworks.Design/Approach/Methods:The noticing of 24 ISTs was examined based on three dimensions:agent,topic,and stance.The data were collected qualitatively through guided questions during the video observation activity,and their noticing levels were analyzed using existing frameworks.Findings:Utilizing the Focused Framework,Chinese ISTs exhibited a greater breadth and depth of noticing,in relation to both students'mathematical thinking and teaching pedagogies.Their noticing abilities surpassed those utilizing an Open Framework,with enhanced sensitivity in adapting their teaching strategies to better address students'mathematical reasoning,The study also revealed limitations in the current practices of classroom observation and teacher reflections.OriginalitylValue:This study provides valuable insights into the noticing abilities of Chinese inservice teachers and the effectiveness of various noticing frameworks in enhancing their skills.It highlights the importance of further research on teacher noticing within Eastern contexts.The findings have significant implications for teachers'professional development,advocating for the integration of noticing frameworks into teacher education programs to improve teachers'abilities to discern critical elements of students'mathematical thinking and pedagogical practices.
文摘This study explores the feasibility of electromagnetic acoustic transducers(EMATs)for ultrasonic rail inspection,focusing on bulk wave generation from the rail head and on defect detection at the central part of the rail foot.As a contactless method,EMATs could overcome some known limitations of conventional ultrasonic techniques,but require further validation.Differ-ent campaigns of experimental tests were performed,evaluating,by means of a probability of detection approach,the response of the technique to several artificial semi-elliptical flaws of increasing size and by considering two sensors characterized by different working frequencies.In contact,static tests allowed to assess the basic feasibility of the inspection technique and showed a linear response to defect size,saturating when defect width exceeded the rail web thickness.Dynamic tests allowed to introduce the effects of lift-off on signal responses.During all tests,the higher-frequency sensor outperformed the lower-frequency one.Finally,full-scale bogie tests on an indoor permanent track installation,comprehensive of defec-tive rails,confirmed the higher flaw detection rates of the higher-frequency sensor,with minimal detection failures despite occasional false alarms.EMATs showed encouraging results for in-motion rail inspection:with further technical development and optimization,this technique could enhance ultrasonic rail inspection by diagnostic trains.
文摘A method of predicting design pressure and burn-through of in-service welding pipes was established. Temperature distributions of in-service welding under variable parameters were simulated by FEM. The effect of flowing of internal media was regarded as forced convection. Based on the numerical results, design pressure of the pipe can be obtained and burn-through can be predicted. It can be concluded that the design pressure decreases with the increasing of heat input. RSF and design pressure of the pipe increase with the increasing of flow rate. There is a range in which the increase changes greatly. For in-service welding, the range should be considered adequately to determine operating condition optimally. RSF increases with the increasing of pipe wall thickness. While the thickness increases to an extent, RSF shows little increase. Accord- ing to the curves of design pressure versus different parameters, safe working pressure can be achieved.
基金The authors disclosed receipt of the following financial support for the research,authorship,and/or publication of this article:This research was supported by the EDUFI Fellowship[decision number:OPH-645-2021]Finnish National Agency for Education(Opetushallitus).
文摘Purpose:This paper aims to examine the participation experiences of a sample of Chinese teacher trainees and their Finnish teacher trainer on an in-service teacher training program exported from Finland to Beijing,China.Design/Approach/Methods:Six science teachers from Beijing and their Finnish teacher trainer participated in semi-structured interviews.From the ideological perspective of international education,a total of eight semi-structured interviews were analyzed through qualitative content analysis.Findings:The results show that all interviewees were highly motivated to learn from the Other's education system and culture.Some participants benefited from a broader understanding of the Self's and the Other's education systems,while others did not.The interviewees also described some participation challenges,such as language barriers and practices that adapted learner-centered teaching approaches in Beijing schools.Furthermore,the interviewees mentioned future expectations of more in-depth communication between Finland and China.Originality/Value:Some recommendations for better training outcomes,improving the quality of participation experiences,and reaching more mutual understandings were discussed at the end of this study.
基金supported by a research grant from the Medical Research Program of Chongqing University Three Gorges Hospital(No.2022YJKYXM-017).
文摘Objective:The objective of this study is to develop and evaluate a structured clinical rotation-based emergency response training program to enhance nurses’emergency competence,theoretical knowledge,and technical skills.Methods:A comprehensive emergency training program was developed,and a randomized controlled trial was implemented from June 2022 to May 2023 at a tertiary general hospital in Chongqing,China.The study involved 214 nurses,with 106 participants in the intervention group receiving a 3-month innovative emergency response competence training and 108 in the control group undergoing conventional training.Postintervention assessments evaluated emergency response capabilities using the Emergency Response Ability Assessment Scale for Nurses in Public Health Emergencies,theoretical knowledge through a self-designed comprehensive theoretical assessment instrument,technical skills using a standardized skill assessment form,and training satisfaction through two distinct feedback instruments.Results:The emergency response ability scores were significantly higher in the intervention group compared to controls(3.99±0.18 vs.2.53±0.25,P<0.05).Theoretical assessment scores showed marked improvement in the intervention group versus the control group(85.31±4.40 vs.52.45±6.19,P<0.05).Technical skill performance was significantly better in the intervention group than that in controls(94.47±1.64 vs.86.39±2.36,P<0.05).Training satisfaction was higher among intervention group nurses compared to controls(4.53±0.23 vs.4.00±0.38,P<0.05),with nursing managers also reporting greater satisfaction with the intervention program versus conventional training(4.57±0.49 vs.3.92±0.79,P<0.05).Conclusion:The clinical rotation-based structured emergency response training program effectively enhances nurses’emergency competencies,theoretical knowledge,and technical skills.These findings provide both theoretical foundations and practical guidelines for developing emergency response and specialized nursing competence training programs.
