Introduction: Work-aggravated asthma is pre-existing or concomitant asthma whose symptoms are aggravated by the work environment. The aim of this study was to determine the prevalence of this pathology and its associa...Introduction: Work-aggravated asthma is pre-existing or concomitant asthma whose symptoms are aggravated by the work environment. The aim of this study was to determine the prevalence of this pathology and its associated factors among bakery workers in Abidjan. Materials and Methods: This descriptive and analytical cross-sectional study was conducted over a period of four (4) months from 18 December 2019 to 18 April 2020. Two questionnaires were used, one on employees and the other on the indoor environment of bakeries. In addition, a spirometry test was performed on all bakery workers. Statistical analysis was performed using stata 15.1 software. Results: A total of 599 bakery employees, including bakers (59.73%), sales assistants/ cashiers (23.52%), cleaners (6.34%) and administrative staff (10.18%), were investigated. The mean age was 30.8 ± 8 years, with a sex ratio (M/F) = 2.2. Asthma symptoms were found in 95 (15.86%) employees, of whom 74 (77.9%) had work-related asthma and 11 (14.9%) had asthma aggravated by work. The factors associated with work-aggravated asthma were personal or family history of allergy or atopy [ORa = 3.75;CI95%: 1.56 - 8.93;p = 0.003], exposure to dust [ORa = 5.01;CI95%: 1.43 - 7.50;p = 0.011] and humidity level (60% - 70%) [ORa = 1.80;CI 95%: 0.99 - 3.28;p = 0.05]. Conclusion: Work-aggravated asthma is a reality in bakeries in Abidjan, with an estimated prevalence of 14.9%. Two of the three factors associated with this condition suggest a link with indoor air pollution. Combating air pollution in these establishments must therefore be a priority for the relevant authorities, in order to provide employees with a working environment that protects their health.展开更多
Work-related diseases can have health consequences including stress- and mental health-related disorders, musculoskeletal disorders, and cancer and skin complaints due to exposure to biological agents. We aimed to inv...Work-related diseases can have health consequences including stress- and mental health-related disorders, musculoskeletal disorders, and cancer and skin complaints due to exposure to biological agents. We aimed to investigate the prevalence of work-related diseases among bank employees and the independent risk factors for these diseases and to highlight measures that can be taken to prevent the occurrence of such diseases, to improve holistic health, and to raise awareness about work-related disease. Data were collected during face-to-face interviews (n = 796) in the recruitment phase of an international public bank in Istanbul, Türkiye or during periodic examinations in the bank between 2017 and 2019. Data, including socio-demographic characteristics, medical anamneses, physical examination results, laboratory findings, occupational accidents, and occupational disease frequency data, were retrospectively examined, and the results were statistically evaluated. Data were analyzed using the SPSS Statistics 17.0 (IBM Corporation, Armonk, NY, USA) package program. Results were considered statistically significant at p < 0.05. Age, female gender, dust exposure, vibration in the workplace were found to be significantly associated with musculoskeletal disorders, while age and work-related noise was found to be related to digestive system problems and dust exposure had significant relation with psychiatric disorders. Work-related diseases among bank employees are a priority that should be addressed by all relevant authorities to enable people to lead healthy lives in physical, mental, spiritual, and social terms.展开更多
<strong>Background:</strong> The Work-As-Imagined (WAI) is a plan that is expected to be performed before surgery, and the Work-As-Done (WAD) is the result of work actually done. In order to perform safe a...<strong>Background:</strong> The Work-As-Imagined (WAI) is a plan that is expected to be performed before surgery, and the Work-As-Done (WAD) is the result of work actually done. In order to perform safe and high-quality surgery for the individual surgeon, the surgical team, and hospital organization as a system, we have to reconcile the WAI and the WAD in resilience engineering for the real world of surgical healthcare. <strong>Objective:</strong> Based on the resilient healthcare theory, we would like to clarify the actual way of reconciling the WAI and WAD in surgery. <strong>Material and Methods:</strong> As a typical model of thoracic surgery, we use a lobectomy case for lung cancer. We describe a surgeon’s WAI and WAD, and we explain the anticipating, monitoring, responding, and learning based on the resilient healthcare theory. We reveal the gaps between the WAI and WAD during an operation, we consider the surgeon’s thinking and actual performance, and we describe the actual way of reconciling the WAI and WAD for the surgeon and surgical team. <strong>Outcomes:</strong> We described three scenes in the operating room, which are 1) by individual surgeon: adjustment for intrathoracic adhesion;2) by surgical team: adjustment for pulmonary artery bleeding;and 3) by surgical team with multi-professionals in the operating room: adjustment for life threatening pulmonary artery critical bleeding. <strong>Conclusion:</strong> In order to implement a resilient healthcare theory in everyday surgical work, it is important that 1) learning of incidents and the experience of doing well for unexpected events as lessons, and 2) constructing a circulation mechanism of anticipating, monitoring, responding, and learning.展开更多
The metastable austenite was transformed to martensite by prestrain tension of SUS304 stainless steel to study the influence of transformed martensite on its subsequent work-hardening behavior under the uniaxial tensi...The metastable austenite was transformed to martensite by prestrain tension of SUS304 stainless steel to study the influence of transformed martensite on its subsequent work-hardening behavior under the uniaxial tensile condition. The X-ray diffractometer （XRD） was employed to detect the transformed martensite. Results showed that the volume fraction of transformed martensite increases with increasing prestrain. The pre-transformed martensite in the microstructure remarkably affects the deformation behavior of the steel, and the strength increases and the elongation decreases. The work-hardening curve of prestrained specimens observably changes with true strain. The work-hardening exponent n of stainless steel decreases with the increase of pre-transformed martensite. The achievement is a significant contribution to the process design during pressing.展开更多
The plastic work-heat conversion coefficient is one key parameter for studying the work-heat conversion under dynamic deformation of materials. To explore this coefficient of 7075-T651 aluminum alloy under dynamic com...The plastic work-heat conversion coefficient is one key parameter for studying the work-heat conversion under dynamic deformation of materials. To explore this coefficient of 7075-T651 aluminum alloy under dynamic compression, dynamic compression experiments using the Hopkinson bar under four groups of strain rates were conducted, and the temperature signals were measured by constructing a transient infrared temperature measurement system. According to stress versus strain data as well as the corresponding temperature data obtained through the experiments, the influences of the strain and the strain rate on the coefficient of plastic work converted to heat were analyzed.The experimental results show that the coefficient of plastic work converted to heat of 7075-T651 aluminum alloy is not a constant at the range of 0.85–1 and is closely related to the strain and the strain rate. The change of internal structure of material under high strain rate reduces its energy storage capacity, and makes almost all plastic work convert into heat.展开更多
Limitations of various accumulators in hybrid hydraulic excavator are analyzed. A program using capacitor as the accumulator based on constant work-point control is put forward. A simulating experimental system of hyb...Limitations of various accumulators in hybrid hydraulic excavator are analyzed. A program using capacitor as the accumulator based on constant work-point control is put forward. A simulating experimental system of hybrid construction machinery is established, and experimental study on constant work-point control for parallel hybrid system with capacitor accumulator is carried out using the pressure and flow rate derived from boom cylinder of hydraulic excavator in actual work as the simulating loads. A program of double work-point control is proposed and proved by further experiments.展开更多
The instantaneous thermal expansion behavior of-two-phase heterogeneous materials subjected to a uniform temperature change is explored in the present study. The matrix phase is assumed to be a work-hardening ductile ...The instantaneous thermal expansion behavior of-two-phase heterogeneous materials subjected to a uniform temperature change is explored in the present study. The matrix phase is assumed to be a work-hardening ductile metal and the dispersive phase is assumed to consist of either aligned or randomly-oriented, elastic,, spheroidal inhomogeneities. The plastic flow and decreasing stiffness of the matrix during Eshelby's transformation strain of the equivalent inclusions are accounted for by using the deformation theory of plasticity. The explicit results of the instantaneous overall thermal expansion coefficients and the critical inelastic temperature changes are presented for aligned disc- and fiber-inclusions. For the spherical and randomly-oriented spheroidal inclusion, the present study demonstrates that when the yielding of the composites is governed by the average matrix stress, the overall response is always elastic in spite of the temperature change.展开更多
We analyze a large-scale molecular dynamics simulation of work hardening in a model system of a ductile solid. With tensile loading, we observe emission of thousands of dislocations from two sharp cracks. The dislocat...We analyze a large-scale molecular dynamics simulation of work hardening in a model system of a ductile solid. With tensile loading, we observe emission of thousands of dislocations from two sharp cracks. The dislocations interact in a complex way, revealing three fundamental mechanisms of work-hardening in this ductile material. These are (1) dislocation cutting processes, jog formation and generation of trails of point defects; (2) activation of secondary slip systems by Frank-Read and cross-slip mechanisms; and (3) formation of sessile dislocations such as Lomer-Cottrell locks. We report the discovery of a new class of point defects referred to as trail of partial point defects, which could play an important role in situations when partial dislocations dominate plasticity. Another important result of the present work is the rediscovery of the Fleischer-mechanism of cross-slip of partial dislocations that was theoretically proposed more than 50 years ago, and is now, for the first time, confirmed by atomistic simulation. On the typical time scale of molecular dynamics simulations, the dislocations self-organize into a complex sessile defect topology. Our analysis illustrates numerous mechanisms formerly only conjectured in textbooks and observed indirectly in experiments. It is the first time that such a rich set of fundamental phenomena have been revealed in a single computer simulation, and its dynamical evolution has been studied. The present study exemplifies the simulation and analysis of the complex nonlinear dynamics of a many-particle system during failure using ultra-large scale computing.展开更多
In this paper, a fast and accurate work-piece detection and measurement algorithm is proposed based on top-down feature extraction and bottom-up saliency estimation. Firstly, a top-down feature extraction method based...In this paper, a fast and accurate work-piece detection and measurement algorithm is proposed based on top-down feature extraction and bottom-up saliency estimation. Firstly, a top-down feature extraction method based on the prior knowledge of work- pieces is presented, in which the contour of a work-piece is chosen as the major feature and the corresponding template of the edges is created. Secondly, a bottom-up salient region estimation algorithm is proposed, where the image boundaries are labelled as background queries, and the salient region can be detected by computing contrast against image boundary. Finally, the calibration method for vision system with telecentric lens is discussed, and the dimensions of the work-pieces are measured. In addition, strategies such as image pyramids and a stopping criterion are adopted to speed-up the algorithm. An automatic system embedded with the proposed detection and measurement algorithm combining top-down and bottom-up saliency （DM-TBS） is designed to pick out defective work-pieces without any manual auxiliary. Experiments and results demonstrate the effectiveness of the proposed method.展开更多
Background and Objectives: To determine whether chest CT-scan in patients with cervical or endometrial cancer is of additional value for planning initial treatment and work-up. Methods: A retrospective analysis was pe...Background and Objectives: To determine whether chest CT-scan in patients with cervical or endometrial cancer is of additional value for planning initial treatment and work-up. Methods: A retrospective analysis was performed of 465 patients diagnosed with cervical or endometrial cancer between January 2003 and December 2007. All patients who underwent a chest CT-scan before treatment were included for analysis. Results: Out of 465 patients 74 patients underwent a pre-treatment chest CT-scan (cervical cancer, n = 58, and endometrial cancer, n = 26). Abnormalities were detected in 53.4% (31/58) and 73.1% (19/26) of patients with cervical and endometrial cancer, respectively. The majority of abnormalities were presumed to be benign, yet work-up was adjusted in 28.6% (13/58 and 11/26), and therapy was adjusted in 17.6% (6/58, and 7/26) of patients with cervical and endometrial cancer. Pulmonary metastasis were observed in 10.3% (6/58) and 24.1% (7/26) of patients with cervical cancer, and endometrial cancer, respectively. Most patients with pulmonary metastasis presented with extended disease based on clinical examination. Conclusions: Chest CT scans in patients with cervical and endometrial cancer frequently demonstrate abnormalities that are most likely benign, yet work-up is adjusted in a substantial number of cases. Therefore, chest CT-scan is only recommended for those patients with a clinical suspicion of extended disease.展开更多
Objectives: We measured health inequalities among employed Luxembourg residents over time and the socio-economic and work-related determinants. Design and Setting: Longitudinal data were obtained from the Socio-econom...Objectives: We measured health inequalities among employed Luxembourg residents over time and the socio-economic and work-related determinants. Design and Setting: Longitudinal data were obtained from the Socio-economic Liewen zu Lëtzebuerg/European Union Survey on Income and Living Conditions, which has been conducted each year since 2003 in Luxembourg. Participants: Participants comprised 727 Luxembourg residents (58% men), aged between 21 and 55 years in 2003, who were employed between 2003 and 2012. Primary and Secondary Outcomes Measured: The variable of interest was self-reported health. We used transition indicators on work-related factors to consider changes that individuals may have experienced in their job over this period. Results: People who moved from a part-time to a full-time contract (odds ratio (OR): 5.52, confidence interval (CI): 1.55 - 19.73), and those who moved from the 3rd or 4th quartile of earnings to the 1st or 2nd quartile (OR: 2.48, CI: 1.02 - 6.05) between 2003 and 2012, had a higher risk of being in poor health in 2012. The risk of deterioration in self-reported health in 2012 among people who were healthy in 2003 was associated with the type of contract, economic activity, and occupation. Conclusion: Health inequalities occur among employed people in Luxembourg. Their importance varies according to work-related characteristics and economic activity. Our findings showed that declined health status was associated with contract type, profession, and economic activity. This suggests that measures should be taken to maintain good health for people working in these specific occupations or economic sectors (e.g. preventive action, reduction of risk exposure, change of occupation in the same company, and so on).展开更多
X-ray diffraction Fourier profile analysis has been performed for polycrystalline α-brass plate with 31.55 wt-% Zn after a series of uniaxial tensile tests with different strain rates. Dislocation density p and confi...X-ray diffraction Fourier profile analysis has been performed for polycrystalline α-brass plate with 31.55 wt-% Zn after a series of uniaxial tensile tests with different strain rates. Dislocation density p and configuration parameter M may be presented as a function of ap- plied stress σ_a.A mechanism of alternative long-range and short-range strain hardening has been proposed.展开更多
This paper addresses the topic of an interdisciplinary approach of chronic pain management from a biopsychosocial perspective. The first section provides an introduction to the definitions and theories of chronic pain...This paper addresses the topic of an interdisciplinary approach of chronic pain management from a biopsychosocial perspective. The first section provides an introduction to the definitions and theories of chronic pain and the various contributing factors (psychological, interpersonal/environmental and social support, and vocational). The second section presents the role of various health care professions (medical doctors, nurses, physical therapists, occupational therapists, psychologists and rehabilitation counselors) and the evidence of their treatment effectiveness. The third section discusses the concept of an interdisciplinary pain rehabilitation program (IPRP) and its evidence to support its effectiveness. Finally, the clinical implications of rehabilitation counseling and psychology as part of the inter-disciplinary program in treating individuals with chronic pain will be highlighted.展开更多
The preparation process of the CO gas sensor used at normal temperature is presented.The electric conductance of this type of sensor evolved oscillation from regularly when the sensor is exposed to low level CO gas.Th...The preparation process of the CO gas sensor used at normal temperature is presented.The electric conductance of this type of sensor evolved oscillation from regularly when the sensor is exposed to low level CO gas.The gas sensing mechanism was investigated by its crystalline structure.The mechanism of information sensing,which was the concurrence of the grain boundary barrier control and the crystal surface control,is discussed.展开更多
The effect of C,Mn and heat-treatment on work-hardening of austenitic Mn steel and the work-hardening mechanism have been investigated under non-severe impact loading condition.The results show that the ability of wor...The effect of C,Mn and heat-treatment on work-hardening of austenitic Mn steel and the work-hardening mechanism have been investigated under non-severe impact loading condition.The results show that the ability of work-hardening in- creases with the increase of C and aging tempera- ture but decreases with Mn.The work-hardening with high austenitic stability results mainly from dislocations,and that with low austenitic stability results mainly from combined effects of strain-in- duced martensite and high density of dislocations under non-severe impact loading conditions.The wear resistance of medium manganese steel (Mn7) is 1.64-2.46 times that of Hadfield steel (Mnl3).展开更多
We aimed to identify the challenges parents face raising preschool-aged children when trying to maintain a good work-family balance. We also highlight how public health nurses can support the community in this regard....We aimed to identify the challenges parents face raising preschool-aged children when trying to maintain a good work-family balance. We also highlight how public health nurses can support the community in this regard. Seven Japanese parents volunteered to participate, and individual in-depth interviews were conducted from May to October 2021. We analyzed the recorded interview data using qualitative descriptive methods. Three main themes concerning work-family balance challenges were extracted: 1) conflicts between parents’ childcare and work roles, 2) issues related to institutions and social systems, and 3) a lack of informal support. Factors contributing to the difficulties were a lack of time to spend with their children;an imbalance in the division of housework and childcare roles between married couples;the employment environment in Japan that makes it difficult to pursue a career while raising children;a lack of childcare services, including childcare for sick children;inadequate consultation systems;and an aging grandparents’ generation owing to late marriages. To solve this problem, we suggest that in addition to establishing a reliable system for providing childcare, local public health nurses should work with childcare workers to create an environment in which parents feel comfortable discussing work-family balance, considering the time constraints of parents during the childrearing period, and use nursery schools as a place for parent-child support.展开更多
Objectives: Aging workforces with increasing numbers of chronic conditions require health initiatives with greater workplace focus. A regional pension insurance introduced a Return To Work (RTW) strategy for insurants...Objectives: Aging workforces with increasing numbers of chronic conditions require health initiatives with greater workplace focus. A regional pension insurance introduced a Return To Work (RTW) strategy for insurants with chronic conditions. The objective was to identify the degree of implementation of work related measures in medical rehabilitation and the extent of RTW outcomes. Methods: 5883 insurants were considered. Severe Restriction of Work Ability (SRWA), Work-related Medical Rehabilitation (WMR), and Case Management (CM) were examined for 2008 and 2012. An Index of Employment status (IoE) was used in a logistic regression. Results: Utilization of WMR raised from 12.3% in 2008 to 66.1% in 2012. The proportion of insurants with SRWA and WMR grew from 8% up to 40.1%. In 2008, 14.7% of insurants with SRWA received WMR;in 2012, it grew to 76.6%. On the other hand, in 2012 26% got WMR without SRWA and 12.2% had SRWA and got no WMR. CM was not conducted in 2008 but reached 20.2% in 2012. Across all indications, WMR resulted in positive RTW as measured by IoE: OR = 0.75 (KI-95%: 0.67 - 0.86). Conclusion: WMR was successfully implemented according to the German guideline. There is a need to optimize the linkage between SRWA and WMR and CM to provide need-based care.展开更多
Introduction: Work-related musculoskeletal disorders (WRMSDs) are a public health problem and have forced many workers to quit their jobs prematurely. This study investigated the prevalence and risk factors of WRMSDs ...Introduction: Work-related musculoskeletal disorders (WRMSDs) are a public health problem and have forced many workers to quit their jobs prematurely. This study investigated the prevalence and risk factors of WRMSDs among Healthcare workers in five reference hospitals in the City of Douala-Cameroon. Methods: A cross-sectional study was conducted in 2022 among 561 healthcare workers working in five reference hospitals in the city of Douala, Cameroon. Participants were selected using a convenient sampling technique. Data were collected with structured questionnaires;data on the demographics and risk factors were collected using a well-designed questionnaire, while estimation of the prevalence of WRMSDs was done using the Modified Nordic questionnaire. Results: The overall prevalence rate of WRMSDs among healthcare workers in Douala hospitals was 83.4% (468/561). The prevalence per professional groups was as follows: 88.8% (71) for Medical Laboratory Scientists (MLS), 81.9% (289) for nurses, 21 (80.8%) for Physiotherapists (PTs) and 78.8% (41) for Medical Doctors (MDs). There was a significant difference (p = 0.001) in the prevalence of WRMSDs with respect to place of work where healthcare workers from HLD recorded the highest prevalence 89.9%, while Healthcare workers from NBDH were 2.91 times at risk (AOR = 2.91;95% CI: 1.32 - 6.41;p = 0.001) to develop WRMSDs than healthcare workers in the other hospitals. With respect to body region, the highest prevalence of WRMSDs was recorded on the lower back, 58.8% with the lowest at the elbows 11.2%. The age group 30 to 39 years was significantly associated with WRMSDs at level of the shoulder (p = 0.002), upper back (p = 0.019), elbows (p Conclusion: The overall prevalence rate of WRMSDs among healthcare workers in Douala hospitals was high. The prevalence of WRMSDs is highest among MLS and nurses and the most affected body parts are;lower back, neck and upper back. Working on the same posture, stressful job, and repetitive tasks were the major risk factors associated to WRMSDs among healthcare workers in Douala hospitals.展开更多
文摘Introduction: Work-aggravated asthma is pre-existing or concomitant asthma whose symptoms are aggravated by the work environment. The aim of this study was to determine the prevalence of this pathology and its associated factors among bakery workers in Abidjan. Materials and Methods: This descriptive and analytical cross-sectional study was conducted over a period of four (4) months from 18 December 2019 to 18 April 2020. Two questionnaires were used, one on employees and the other on the indoor environment of bakeries. In addition, a spirometry test was performed on all bakery workers. Statistical analysis was performed using stata 15.1 software. Results: A total of 599 bakery employees, including bakers (59.73%), sales assistants/ cashiers (23.52%), cleaners (6.34%) and administrative staff (10.18%), were investigated. The mean age was 30.8 ± 8 years, with a sex ratio (M/F) = 2.2. Asthma symptoms were found in 95 (15.86%) employees, of whom 74 (77.9%) had work-related asthma and 11 (14.9%) had asthma aggravated by work. The factors associated with work-aggravated asthma were personal or family history of allergy or atopy [ORa = 3.75;CI95%: 1.56 - 8.93;p = 0.003], exposure to dust [ORa = 5.01;CI95%: 1.43 - 7.50;p = 0.011] and humidity level (60% - 70%) [ORa = 1.80;CI 95%: 0.99 - 3.28;p = 0.05]. Conclusion: Work-aggravated asthma is a reality in bakeries in Abidjan, with an estimated prevalence of 14.9%. Two of the three factors associated with this condition suggest a link with indoor air pollution. Combating air pollution in these establishments must therefore be a priority for the relevant authorities, in order to provide employees with a working environment that protects their health.
文摘Work-related diseases can have health consequences including stress- and mental health-related disorders, musculoskeletal disorders, and cancer and skin complaints due to exposure to biological agents. We aimed to investigate the prevalence of work-related diseases among bank employees and the independent risk factors for these diseases and to highlight measures that can be taken to prevent the occurrence of such diseases, to improve holistic health, and to raise awareness about work-related disease. Data were collected during face-to-face interviews (n = 796) in the recruitment phase of an international public bank in Istanbul, Türkiye or during periodic examinations in the bank between 2017 and 2019. Data, including socio-demographic characteristics, medical anamneses, physical examination results, laboratory findings, occupational accidents, and occupational disease frequency data, were retrospectively examined, and the results were statistically evaluated. Data were analyzed using the SPSS Statistics 17.0 (IBM Corporation, Armonk, NY, USA) package program. Results were considered statistically significant at p < 0.05. Age, female gender, dust exposure, vibration in the workplace were found to be significantly associated with musculoskeletal disorders, while age and work-related noise was found to be related to digestive system problems and dust exposure had significant relation with psychiatric disorders. Work-related diseases among bank employees are a priority that should be addressed by all relevant authorities to enable people to lead healthy lives in physical, mental, spiritual, and social terms.
文摘<strong>Background:</strong> The Work-As-Imagined (WAI) is a plan that is expected to be performed before surgery, and the Work-As-Done (WAD) is the result of work actually done. In order to perform safe and high-quality surgery for the individual surgeon, the surgical team, and hospital organization as a system, we have to reconcile the WAI and the WAD in resilience engineering for the real world of surgical healthcare. <strong>Objective:</strong> Based on the resilient healthcare theory, we would like to clarify the actual way of reconciling the WAI and WAD in surgery. <strong>Material and Methods:</strong> As a typical model of thoracic surgery, we use a lobectomy case for lung cancer. We describe a surgeon’s WAI and WAD, and we explain the anticipating, monitoring, responding, and learning based on the resilient healthcare theory. We reveal the gaps between the WAI and WAD during an operation, we consider the surgeon’s thinking and actual performance, and we describe the actual way of reconciling the WAI and WAD for the surgeon and surgical team. <strong>Outcomes:</strong> We described three scenes in the operating room, which are 1) by individual surgeon: adjustment for intrathoracic adhesion;2) by surgical team: adjustment for pulmonary artery bleeding;and 3) by surgical team with multi-professionals in the operating room: adjustment for life threatening pulmonary artery critical bleeding. <strong>Conclusion:</strong> In order to implement a resilient healthcare theory in everyday surgical work, it is important that 1) learning of incidents and the experience of doing well for unexpected events as lessons, and 2) constructing a circulation mechanism of anticipating, monitoring, responding, and learning.
基金Item Sponsored by National Natural Science Foundation of China (50675128 50975166)
文摘The metastable austenite was transformed to martensite by prestrain tension of SUS304 stainless steel to study the influence of transformed martensite on its subsequent work-hardening behavior under the uniaxial tensile condition. The X-ray diffractometer （XRD） was employed to detect the transformed martensite. Results showed that the volume fraction of transformed martensite increases with increasing prestrain. The pre-transformed martensite in the microstructure remarkably affects the deformation behavior of the steel, and the strength increases and the elongation decreases. The work-hardening curve of prestrained specimens observably changes with true strain. The work-hardening exponent n of stainless steel decreases with the increase of pre-transformed martensite. The achievement is a significant contribution to the process design during pressing.
基金supported by the National Nature Science Foundation of China (Grants 11132011 and 11472288)
文摘The plastic work-heat conversion coefficient is one key parameter for studying the work-heat conversion under dynamic deformation of materials. To explore this coefficient of 7075-T651 aluminum alloy under dynamic compression, dynamic compression experiments using the Hopkinson bar under four groups of strain rates were conducted, and the temperature signals were measured by constructing a transient infrared temperature measurement system. According to stress versus strain data as well as the corresponding temperature data obtained through the experiments, the influences of the strain and the strain rate on the coefficient of plastic work converted to heat were analyzed.The experimental results show that the coefficient of plastic work converted to heat of 7075-T651 aluminum alloy is not a constant at the range of 0.85–1 and is closely related to the strain and the strain rate. The change of internal structure of material under high strain rate reduces its energy storage capacity, and makes almost all plastic work convert into heat.
文摘Limitations of various accumulators in hybrid hydraulic excavator are analyzed. A program using capacitor as the accumulator based on constant work-point control is put forward. A simulating experimental system of hybrid construction machinery is established, and experimental study on constant work-point control for parallel hybrid system with capacitor accumulator is carried out using the pressure and flow rate derived from boom cylinder of hydraulic excavator in actual work as the simulating loads. A program of double work-point control is proposed and proved by further experiments.
基金This work was supported by the National Science Foundation under the Grant 19302017 and 59472031
文摘The instantaneous thermal expansion behavior of-two-phase heterogeneous materials subjected to a uniform temperature change is explored in the present study. The matrix phase is assumed to be a work-hardening ductile metal and the dispersive phase is assumed to consist of either aligned or randomly-oriented, elastic,, spheroidal inhomogeneities. The plastic flow and decreasing stiffness of the matrix during Eshelby's transformation strain of the equivalent inclusions are accounted for by using the deformation theory of plasticity. The explicit results of the instantaneous overall thermal expansion coefficients and the critical inelastic temperature changes are presented for aligned disc- and fiber-inclusions. For the spherical and randomly-oriented spheroidal inclusion, the present study demonstrates that when the yielding of the composites is governed by the average matrix stress, the overall response is always elastic in spite of the temperature change.
文摘We analyze a large-scale molecular dynamics simulation of work hardening in a model system of a ductile solid. With tensile loading, we observe emission of thousands of dislocations from two sharp cracks. The dislocations interact in a complex way, revealing three fundamental mechanisms of work-hardening in this ductile material. These are (1) dislocation cutting processes, jog formation and generation of trails of point defects; (2) activation of secondary slip systems by Frank-Read and cross-slip mechanisms; and (3) formation of sessile dislocations such as Lomer-Cottrell locks. We report the discovery of a new class of point defects referred to as trail of partial point defects, which could play an important role in situations when partial dislocations dominate plasticity. Another important result of the present work is the rediscovery of the Fleischer-mechanism of cross-slip of partial dislocations that was theoretically proposed more than 50 years ago, and is now, for the first time, confirmed by atomistic simulation. On the typical time scale of molecular dynamics simulations, the dislocations self-organize into a complex sessile defect topology. Our analysis illustrates numerous mechanisms formerly only conjectured in textbooks and observed indirectly in experiments. It is the first time that such a rich set of fundamental phenomena have been revealed in a single computer simulation, and its dynamical evolution has been studied. The present study exemplifies the simulation and analysis of the complex nonlinear dynamics of a many-particle system during failure using ultra-large scale computing.
基金supported by National Natural Science Foundation of China(Nos.61379097,91748131,61771471,U1613213 and 61627808)National Key Research and Development Plan of China(No.2017YFB1300202)Youth Innovation Promotion Association Chinese Academy of Sciences(CAS)(No.2015112)
文摘In this paper, a fast and accurate work-piece detection and measurement algorithm is proposed based on top-down feature extraction and bottom-up saliency estimation. Firstly, a top-down feature extraction method based on the prior knowledge of work- pieces is presented, in which the contour of a work-piece is chosen as the major feature and the corresponding template of the edges is created. Secondly, a bottom-up salient region estimation algorithm is proposed, where the image boundaries are labelled as background queries, and the salient region can be detected by computing contrast against image boundary. Finally, the calibration method for vision system with telecentric lens is discussed, and the dimensions of the work-pieces are measured. In addition, strategies such as image pyramids and a stopping criterion are adopted to speed-up the algorithm. An automatic system embedded with the proposed detection and measurement algorithm combining top-down and bottom-up saliency （DM-TBS） is designed to pick out defective work-pieces without any manual auxiliary. Experiments and results demonstrate the effectiveness of the proposed method.
文摘Background and Objectives: To determine whether chest CT-scan in patients with cervical or endometrial cancer is of additional value for planning initial treatment and work-up. Methods: A retrospective analysis was performed of 465 patients diagnosed with cervical or endometrial cancer between January 2003 and December 2007. All patients who underwent a chest CT-scan before treatment were included for analysis. Results: Out of 465 patients 74 patients underwent a pre-treatment chest CT-scan (cervical cancer, n = 58, and endometrial cancer, n = 26). Abnormalities were detected in 53.4% (31/58) and 73.1% (19/26) of patients with cervical and endometrial cancer, respectively. The majority of abnormalities were presumed to be benign, yet work-up was adjusted in 28.6% (13/58 and 11/26), and therapy was adjusted in 17.6% (6/58, and 7/26) of patients with cervical and endometrial cancer. Pulmonary metastasis were observed in 10.3% (6/58) and 24.1% (7/26) of patients with cervical cancer, and endometrial cancer, respectively. Most patients with pulmonary metastasis presented with extended disease based on clinical examination. Conclusions: Chest CT scans in patients with cervical and endometrial cancer frequently demonstrate abnormalities that are most likely benign, yet work-up is adjusted in a substantial number of cases. Therefore, chest CT-scan is only recommended for those patients with a clinical suspicion of extended disease.
文摘Objectives: We measured health inequalities among employed Luxembourg residents over time and the socio-economic and work-related determinants. Design and Setting: Longitudinal data were obtained from the Socio-economic Liewen zu Lëtzebuerg/European Union Survey on Income and Living Conditions, which has been conducted each year since 2003 in Luxembourg. Participants: Participants comprised 727 Luxembourg residents (58% men), aged between 21 and 55 years in 2003, who were employed between 2003 and 2012. Primary and Secondary Outcomes Measured: The variable of interest was self-reported health. We used transition indicators on work-related factors to consider changes that individuals may have experienced in their job over this period. Results: People who moved from a part-time to a full-time contract (odds ratio (OR): 5.52, confidence interval (CI): 1.55 - 19.73), and those who moved from the 3rd or 4th quartile of earnings to the 1st or 2nd quartile (OR: 2.48, CI: 1.02 - 6.05) between 2003 and 2012, had a higher risk of being in poor health in 2012. The risk of deterioration in self-reported health in 2012 among people who were healthy in 2003 was associated with the type of contract, economic activity, and occupation. Conclusion: Health inequalities occur among employed people in Luxembourg. Their importance varies according to work-related characteristics and economic activity. Our findings showed that declined health status was associated with contract type, profession, and economic activity. This suggests that measures should be taken to maintain good health for people working in these specific occupations or economic sectors (e.g. preventive action, reduction of risk exposure, change of occupation in the same company, and so on).
文摘X-ray diffraction Fourier profile analysis has been performed for polycrystalline α-brass plate with 31.55 wt-% Zn after a series of uniaxial tensile tests with different strain rates. Dislocation density p and configuration parameter M may be presented as a function of ap- plied stress σ_a.A mechanism of alternative long-range and short-range strain hardening has been proposed.
文摘This paper addresses the topic of an interdisciplinary approach of chronic pain management from a biopsychosocial perspective. The first section provides an introduction to the definitions and theories of chronic pain and the various contributing factors (psychological, interpersonal/environmental and social support, and vocational). The second section presents the role of various health care professions (medical doctors, nurses, physical therapists, occupational therapists, psychologists and rehabilitation counselors) and the evidence of their treatment effectiveness. The third section discusses the concept of an interdisciplinary pain rehabilitation program (IPRP) and its evidence to support its effectiveness. Finally, the clinical implications of rehabilitation counseling and psychology as part of the inter-disciplinary program in treating individuals with chronic pain will be highlighted.
文摘The preparation process of the CO gas sensor used at normal temperature is presented.The electric conductance of this type of sensor evolved oscillation from regularly when the sensor is exposed to low level CO gas.The gas sensing mechanism was investigated by its crystalline structure.The mechanism of information sensing,which was the concurrence of the grain boundary barrier control and the crystal surface control,is discussed.
文摘The effect of C,Mn and heat-treatment on work-hardening of austenitic Mn steel and the work-hardening mechanism have been investigated under non-severe impact loading condition.The results show that the ability of work-hardening in- creases with the increase of C and aging tempera- ture but decreases with Mn.The work-hardening with high austenitic stability results mainly from dislocations,and that with low austenitic stability results mainly from combined effects of strain-in- duced martensite and high density of dislocations under non-severe impact loading conditions.The wear resistance of medium manganese steel (Mn7) is 1.64-2.46 times that of Hadfield steel (Mnl3).
文摘We aimed to identify the challenges parents face raising preschool-aged children when trying to maintain a good work-family balance. We also highlight how public health nurses can support the community in this regard. Seven Japanese parents volunteered to participate, and individual in-depth interviews were conducted from May to October 2021. We analyzed the recorded interview data using qualitative descriptive methods. Three main themes concerning work-family balance challenges were extracted: 1) conflicts between parents’ childcare and work roles, 2) issues related to institutions and social systems, and 3) a lack of informal support. Factors contributing to the difficulties were a lack of time to spend with their children;an imbalance in the division of housework and childcare roles between married couples;the employment environment in Japan that makes it difficult to pursue a career while raising children;a lack of childcare services, including childcare for sick children;inadequate consultation systems;and an aging grandparents’ generation owing to late marriages. To solve this problem, we suggest that in addition to establishing a reliable system for providing childcare, local public health nurses should work with childcare workers to create an environment in which parents feel comfortable discussing work-family balance, considering the time constraints of parents during the childrearing period, and use nursery schools as a place for parent-child support.
文摘Objectives: Aging workforces with increasing numbers of chronic conditions require health initiatives with greater workplace focus. A regional pension insurance introduced a Return To Work (RTW) strategy for insurants with chronic conditions. The objective was to identify the degree of implementation of work related measures in medical rehabilitation and the extent of RTW outcomes. Methods: 5883 insurants were considered. Severe Restriction of Work Ability (SRWA), Work-related Medical Rehabilitation (WMR), and Case Management (CM) were examined for 2008 and 2012. An Index of Employment status (IoE) was used in a logistic regression. Results: Utilization of WMR raised from 12.3% in 2008 to 66.1% in 2012. The proportion of insurants with SRWA and WMR grew from 8% up to 40.1%. In 2008, 14.7% of insurants with SRWA received WMR;in 2012, it grew to 76.6%. On the other hand, in 2012 26% got WMR without SRWA and 12.2% had SRWA and got no WMR. CM was not conducted in 2008 but reached 20.2% in 2012. Across all indications, WMR resulted in positive RTW as measured by IoE: OR = 0.75 (KI-95%: 0.67 - 0.86). Conclusion: WMR was successfully implemented according to the German guideline. There is a need to optimize the linkage between SRWA and WMR and CM to provide need-based care.
文摘Introduction: Work-related musculoskeletal disorders (WRMSDs) are a public health problem and have forced many workers to quit their jobs prematurely. This study investigated the prevalence and risk factors of WRMSDs among Healthcare workers in five reference hospitals in the City of Douala-Cameroon. Methods: A cross-sectional study was conducted in 2022 among 561 healthcare workers working in five reference hospitals in the city of Douala, Cameroon. Participants were selected using a convenient sampling technique. Data were collected with structured questionnaires;data on the demographics and risk factors were collected using a well-designed questionnaire, while estimation of the prevalence of WRMSDs was done using the Modified Nordic questionnaire. Results: The overall prevalence rate of WRMSDs among healthcare workers in Douala hospitals was 83.4% (468/561). The prevalence per professional groups was as follows: 88.8% (71) for Medical Laboratory Scientists (MLS), 81.9% (289) for nurses, 21 (80.8%) for Physiotherapists (PTs) and 78.8% (41) for Medical Doctors (MDs). There was a significant difference (p = 0.001) in the prevalence of WRMSDs with respect to place of work where healthcare workers from HLD recorded the highest prevalence 89.9%, while Healthcare workers from NBDH were 2.91 times at risk (AOR = 2.91;95% CI: 1.32 - 6.41;p = 0.001) to develop WRMSDs than healthcare workers in the other hospitals. With respect to body region, the highest prevalence of WRMSDs was recorded on the lower back, 58.8% with the lowest at the elbows 11.2%. The age group 30 to 39 years was significantly associated with WRMSDs at level of the shoulder (p = 0.002), upper back (p = 0.019), elbows (p Conclusion: The overall prevalence rate of WRMSDs among healthcare workers in Douala hospitals was high. The prevalence of WRMSDs is highest among MLS and nurses and the most affected body parts are;lower back, neck and upper back. Working on the same posture, stressful job, and repetitive tasks were the major risk factors associated to WRMSDs among healthcare workers in Douala hospitals.
