• 제목/요약/키워드: work conditions

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Taylor의 加工硬化理論의 입장에서 評價한 軟鋼薄板材의 破壞擧動에 관한 硏究 (A study on the fracture behavior of mild steel plate evaluated in the light of Taylor's work hardening theory)

  • 손세원;김상철
    • 대한기계학회논문집
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    • 제12권6호
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    • pp.1335-1342
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    • 1988
  • 본 연구에서는 일반적인 구조물에 가장 많이 사용되는 연강박판재(SM12C)가 반복인장하중을 받았을 경우, 즉 이 재료가 프리응력과 프리변형을 받았을 때 시간의 경과에 따르는 경도, 항복강도 및 가공경화지수의 변화를 살펴보았다. 이와 같은 실 험을 통하여 재료가 서서히 안정화되어가는 상태를 왁인하였으며 이를 기초로 하여 레 지듀얼강도(residual strength)와 피로크랙진전속도의 거동을 체계적으로 구명하여 이 연강박판재의 구조물의 안전사용에 기여하도록 하는데 그 목적을 두었다. 아울러 프 리응력 및 프리변형을 받았을 때의 연강박판재의 기계적 성질의 변화를 Taylor의 가공 경화이론에 대응시켜 검토하였다.

국내 임금근로자의 흡연 유형과 관련요인 연구 (Types of Smoking Statuses and Associated Factors among Korean Wageworkers)

  • 문성미
    • 한국보건간호학회지
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    • 제30권3호
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    • pp.495-511
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    • 2016
  • Purpose: The present study was performed to describe the prevalence of various types of smoking statuses and to identify factors associated with different types among Korean wageworkers. Methods: The prevalence of hardcore smoking, daily smoking, and intermittent smoking was assessed in 2,126 wage workers from the Sixth Korea National Health and Nutrition Examination Survey. The associations of these three types of smoking statuses with sociodemographic characteristics, health conditions, and occupation-related characteristics were also examined in a multinomial logistic regression. Results: In men, the prevalence of hardcore smoking and daily smoking were 11.4% and 30.2%, respectively; and in women, the daily smoking prevalence was 5.6%. The education level was strongly associated with men's hardcore smoking and women's daily smoking. The household income and marital status were associated with women's daily smoking. Among occupation-related characteristics, the regularity of work and night work were associated with men's intermittent smoking. Night work was also associated with women's daily smoking. Employment condition was associated with women's intermittent smoking. Conclusion: The socioeconomic status and health conditions, compared with occupation-related factors, were found to have more influence on smoking. Therefore, antismoking programs that focus on individual characteristics should be developed for Korean wageworkers.

Should Workers Avoid Consumption of Chilled Fluids in a Hot and Humid Climate?

  • Brearley, Matt B.
    • Safety and Health at Work
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    • 제8권4호
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    • pp.327-328
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    • 2017
  • Despite provision of drinking water as the most common method of occupational heat stress prevention, there remains confusion in hydration messaging to workers. During work site interactions in a hot and humid climate, workers commonly report being informed to consume tepid fluids to accelerate rehydration. When questioned on the evidence supporting such advice, workers typically cite that fluid absorption is delayed by ingestion of chilled beverages. Presumably, delayed absorption would be a product of fluid delivery from the gut to the intestines, otherwise known as gastric emptying. Regulation of gastric emptying is multifactorial, with gastric volume and beverage energy density the primary factors. If gastric emptying is temperature dependent, the impact of cooling is modest in both magnitude and duration (${\leq}5$ minutes) due to the warming of fluids upon ingestion, particularly where workers have elevated core temperature. Given that chilled beverages are most preferred by workers, and result in greater consumption than warm fluids during and following physical activity, the resultant increased consumption of chilled fluids would promote gastric emptying through superior gastric volume. Hence, advising workers to avoid cool/cold fluids during rehydration appears to be a misinterpretation of the research. More appropriate messaging to workers would include the thermal benefits of cool/cold fluid consumption in hot and humid conditions, thereby promoting autonomy to trial chilled beverages and determine personal preference. In doing so, temperature-based palatability would be maximized and increase the likelihood of workers maintaining or restoring hydration status during and after their work shift.

Construction Delay Analysis Using Daily Work Report Data for Short Construction Seasons

  • Jamal, Md Shah;Abdelaty, Ahmed;Shrestha, K. Joseph
    • 국제학술발표논문집
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    • The 9th International Conference on Construction Engineering and Project Management
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    • pp.616-623
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    • 2022
  • Some regions and states, such as Wyoming, have harsh weather conditions, forcing most transportation projects to be completed under tight schedules. However, construction projects are not only delayed by weather conditions, but also delayed by other factors such as contractor's competency, resource availability, coordination issues, and safety. Also, the construction method, geographical location of the projects, and inability to follow baseline schedules accurately due to the contractor's resource allocation are also reasons for the delay. This paper discusses the main reasons for the delay in the public transportation projects based on Daily Work Reports (DWRs) from five different transportation projects of the last three years in Wyoming. This paper focuses on the inconsistencies of the contractor's schedules to complete the project according to the baseline schedule. First, the authors collected DWRs and baseline schedules from the Wyoming Department of Transportation (WYDOT). Second, the DWR data are compared against the baseline schedules to determine the reasons for delaying their significance. Finally, the paper presents the recommendations to mitigate the effects of delays on public transportation projects as well as to improve the documentation process of DWR data.

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인력수급 대책을 위한 치과기공사의 보건지소 진출에 관한 연구 - 2012년 틀니보험화 정책을 중심으로 - (The study on the entry of dental technicians in the public health center for a manpower supply and demand plane (Centering around a denture insurance policy in 2012))

  • 이종도;김정숙;박광식
    • 대한치과기공학회지
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    • 제32권4호
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    • pp.417-433
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    • 2010
  • Purpose: This study evaluated the manpower planning of dental technicians. Methods: Methods : Survey was conducted regarding subject's general characteristics, characteristics of dental technician's occupational view and working conditions, and reason to enter into branches of the public health enter. The survey sample consisted of 323 dental technicians (221 male/ 102 female). Survey was conducted for one month from August 1 to September 1 in 2010. Following results were obtained. Results: 1. Regarding general characteristics of the subjects, there was a slight male predilection with 68.4%. Subjects in their 40s occupied the highest proportion of 32.2%. Majority of subjects worked in the big cities (71.5%). Favored working places were dental laboratory (57.6%) and dental hospital or dental clinic (19.5%). Although no position is available in the public sector such as public health center or health care civil servant, 9.3% preferred working in the public health center. Public sector is more favored than 2-year technical colleges or dental supply and equipment companies. In respect to education, 57% of the subjects graduated college. 67.8% were married. Subjects who specialize in the porcelain or all-ceramic were 57.9%. With regard to current position, head of the dental laboratory was most common. 2. Following occupation characteristics were found. Economic reason took the highest proportion when deciding their occupation (39.9%) followed by gaining social experience (36.5%). Majority of the subjects (76.5%) wanted to work as dental technicians until their retirement. 71.5% pursuit to become a manager of the dental laboratory. 76.1% agreed on opening a dental technician position in the public health center. Regarding an authority to lead developing the dental technician position in the public sector, majority of the subject chose ministry of health and welfare (35.6%) and Korean dental technologist association (34.7%). Employment (average, 30%) and turnover rate (average, 36.5%) of dental technology college graduates ranged from 40% to 60%. Most important factors for the employment were practical experience (41.2%) and competency (34.4%). With regard to job satisfaction, so-so as 46.7% and satisfactory was 42.7% 3. In respect to the reason for opening a position in the public health center, 'It is needed to continue denture rogram for elderly patients' obtained the highest score (4.14 point). 'Institutional devices are required to open a position for dental technicians as a public healthcare provider' received high score (4.11 point). 4. Concerning the working conditions, 'professional knowledge is required' received the highest score (4.23) followed by 'too short maternity and parental leave' (4.21). 5. Relationship between general characteristics of the subjects and favor of working in the public health center was investigated. Significant differences were found according to the current and favored working area, favored occupation, education level, marital status, and specialty. Working in the public health center was favored by following subjects: working in mid- or small-sized cities (4.16 point, p<0.05); PhD degree-holder (4.59 point, p<0.01). 6. Among general characteristics of the subjects, significant difference of working conditions was found in the following factors: gender; working areas; favored working areas; favored working positions, and education level. Majority of subjects favored working in big cities and currently work in big cities although satisfaction was comparatively low (3.75 score). 7. Future plan to work in public health center was evaluated according to occupational characteristics. Subject's intention to work in the public healthcare center was significantly affected by opening of dental technician position, leading authority, average turnover rate, and factors affecting employment. Working in the public health care center was favored by the following subjects: Dental technicians who actively supported opening of the dental technician position (4.34 point, p<0.001); subjects who thought the Korean dental technologist association is responsible for the opening of positions in the public sector (4.26 point, p<0.001); and subjects who thought that attitude and character are important for the employment (p<0.001). 8. Concerning difference of working conditions according to the occupational characteristics, significant difference was demonstrated by factors such as a reason to choose to be a dental technician, work plan, pursuing position, responsible authority, average employment rate, and job satisfaction. High standard of working conditions was required in subjects who selected to be a dental technician for the leisure time after work (s.05 point, p<0.01), who planted to work until their marriage (4.25 point, p<0.001), and who pursuit to be a manager (3.98, p<0.05). 9. In respect to influence of general characteristics on the advancement to public health centers, the coefficient of determination (R2) was 0.068 and age affected the working condition with significant difference according to the pvalue. 10. Regarding influence of general characteristics on the advancement to public health centers, the coefficient of determination (R2) was 0.335 and work plan, opening of dental technician position in the public sector, and responsible authority had significant influence over the subject's intention to work in the public health center according to the p-value. 11. With regard to the influence of general characteristics on the advancement to public health centers, the coefficient of determination (R2) was 0.091 and reason to choose to be a dental technician, work plan, and responsible authority significantly affected subject's working conditions. Conclusion: Korean society is becoming a super-aged society according to several statistics. As aged population is rapidly increasing, national health insurance plans to cover denture for senior citizen over 75 years old from 2012. Therefore, dental technicians are urgently needed in the public health centers all over the nation. Many subjects in this study planed to work until their retirement and recognized dental technician's expertise. Ministry of health and welfare and Korean dental technologist association should co-operate each other to prepare foundation and institutional devices for dental technicians to advance into the public health center. This will improve oral health of the population. This study showed urgency of medical facilities and services which meets increasing number of aged population and welfare of the population.

초임 보육교사의 경험과 조직 적응과정에 대한 근거이론 (The Experiences of Novice Teachers in Daycare Centers and the Grounded Theory of their Adjustment Process)

  • 원계선
    • 한국보육지원학회지
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    • 제9권2호
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    • pp.23-46
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    • 2013
  • 본 연구는 초임 보육교사의 적응에 도움을 주기 위한 기초 정보를 제공할 목적으로 수행되었다. 초임 보육교사 5명을 대상으로 심층인터뷰와 교사에 의한 메모일기, 저널, 보육일지등의 자료를 수집하였다. 연구결과, 초임 보육교사의 경험은 어려운 인간관계, 난감한 업무, 잦은 실수의 긴장, 받았거나 받기를 원하는 도움, 경험을 통한 현장 이해와 자기 성찰, 교사로서 보람이 느껴진 순간으로 분류할 수 있었다. 근거이론 접근법으로 조직 적응과정에 대한 이론적 모델을 구성하였다. 초임 보육교사의 적응과정은 부정적인 정서 반응의 현상을 중심으로 인과적 조건, 맥락과 중재적 조건, 부정적 정서를 다루는 전략과 그 결과로 설명할 수 있다. 인과적 조건은 업무 실수와 인간관계의 미숙함이다. 맥락은 학급 유아의 연령, 근무시간과 공간, 업무의 양과 낯섦, 구성원의 성격 특성 그리고 학부모와의 잦은 만남으로 구성된다. 중재적 조건은 초임교사 안내프로그램, 구성원의 도움과 지지, 보상, 교사의 개인성격 특성으로 구성된다. 초임 보육교사는 부정적 정서를 다루기 위해 잊어버리기, 가족이나 친구와 나누기, 긍정적 정서로 전환하도록 노력하기의 세 가지 전략을 사용한다. 전략 사용의 결과는 성장하기, 살아가기, 이직과 전직 고려로 구성된다.

H 기업 프레스 작업자의 근골격계 질환 실태에 관한 연구 (A study on the work-related musculoskeletal disorders of press operators in H company)

  • 이동형;조기훈
    • 한국감성과학회:학술대회논문집
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    • 한국감성과학회 2003년도 춘계학술대회 논문집
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    • pp.29-35
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    • 2003
  • Recently, WRMSD(Work-Related Musculoskeletal Disorders) related to simple and repetitious works has been become big issue and has been studying actively by many korean researchers. However, it is that the researches has been depended on foreign ones because the basic data in each field is short in Korea. In this study, we tried to search the actual conditions and factors on WRMSD of pressing workers. In addition, we tried to search the actual conditions and factors on WRMSD of pressing workers. In addition we examined how the contents of works and postures of workers affected at the disease. Accordingly, these research data will be used for planning the preventive program on WRMSD effectively and implement its program.

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고속 가공을 이용한 금형의 효율적 생산 제 2 부: 사상 공정 및 가공 조건의 선정 (High Speed Machining Considering Efficient Manual Finishing Part II: Optimal Manual Finishing Process and Machining Condition)

  • 김민태;제성욱;이해성;주종남
    • 한국정밀공학회지
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    • 제23권12호
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    • pp.38-45
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    • 2006
  • In this work, optimal finish machining condition considering total time for mold or electrode manufacturing was investigated. First, manual finishing time according to the machining condition was analyzed for the work material. The effect of runout and phase shift of tool path on surface finish was also considered in those analyses. Secondly, optimal manual finishing processes were determined for various machining conditions. Finally, finish machining time and corresponding manual finishing time were taken into account for the estimation of the total time of manufacturing mold. Though small feed per tooth and pick feed reduced the manual finishing time, the finish machining time increased in such conditions. With a machining condition of feed per tooth of 0.2 mm and pick feed of 0.3 mm, the minimum total time of manufacturing mold was achieved in our machining condition.

Fully-coupled 시뮬레이션을 이용한 해상 monopile 풍력 발전기의 응력해석 (Load analysis of an offshore monopile wind turbine using fully-coupled simulation)

  • ;박현철
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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    • pp.480-485
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    • 2009
  • Offshore wind energy is gaining more attention. Ensuring proper design of offshore wind turbines and wind farms require knowledge of the external conditions in which the turbines and associated facilities are to operate. In this work, a three-bladed 5MW upwind wind turbine, which is supported by the monopile foundation, is studied by use of fully coupled aero-hydro-servo-elastic commercial simulation tool, 'GH-Bladed'$^{(R)}$. Specification of the structures are chosen from the OC3 (Offshore Code Comparison Collaboration) under "IEA Wind Annex XXIII-subtask2". The primary external conditions due to wind and waves are simulated. Design Load case 5.2 is investigated in this work. The steady state power curve and power production loads are evaluated. Comparison between different codes is made.

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THERMO-MECHANICAL ANALYSIS OF OPTICALLY ACCESSIBLE QUARTZ CYLINDER UNDER FIRED ENGINE OPERATION

  • Lee, K.S.;Assanis, D.N.
    • International Journal of Automotive Technology
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    • 제1권2호
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    • pp.79-87
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    • 2000
  • Analytical approach was followed in this work under both the steady state and transient operating conditions to find optimum boundary conditions, where the optically accessible quartz engine can run safely without breaking. Temperature and stress distribution was predicted by FEM analysis. In order to validate thermal boundary condition, model reliability and constraint, outside cylinder temperature was measured and previous study was also followed up numerically. To reduce thermal stress level, three types of outside cooling (natural, moderate forced and intensive forced convection) were considered. Effects of clamping force and combustion pressure were conducted to investigate mechanical stress level. Cylinder thickness, was changed to fine the optimum cylinder thickness. The versatile results achieved from this work can be basic indication, which is capable of causing a sudden quartz cylinder breaking during fired operation.

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