• 제목/요약/키워드: heavy-duty

검색결과 444건 처리시간 0.022초

A Numerical Study on Performance of a Heavy-Duty Diesel engine for Power Generation under Natural Gas-Diesel Dual Fuel Operation (발전용 대형 디젤 엔진의 천연가스-디젤혼소 운전 특성에 대한 수치해석 연구)

  • Cho, Jungkeun;Park, Sangjun;Song, Soonho;Hur, Kwang-Beom
    • Journal of the Korean Institute of Gas
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    • 제19권2호
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    • pp.29-36
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    • 2015
  • This study is an 1-D numerical study prior to modification of diesel engine for power plants to natural gas/diesel dual fuel engine using GT-Power with 1.5MW diesel engine for power generation. Natural gas injector was installed to intake manifold for dual fuel engine model. Effects on engine performance and characteristics were investigated when dual fuel is used in unmodified diesel engine. The analysis was done under 5 conditions from 0% to 40% of mixing rate on 720RPM engine speed. As a result of research, the engine performance was decreased as increasing ratio of natural gas. Engine brake power was decreased by 18.4% under 40% mixing rate condition. To clarify the reason, effects of injection timing and period were evaluated with DOE method. Considering this result, optimization was done for these parameters. Also, comparison between performances of dual fueled engine and diesel engine was made after optimizing the timing of injection by DOE method. As a result, engine brake power was decreased by 8.55% under mixing rate 40% condition showing 12.5% improvement.

Evaluation of the Impact of Fuel Economy by Each of Driving Modes for Medium-Size Low-Floor Bus (중형저상버스의 개별주행모드에 따른 연료소비율 평가)

  • Jung, Jae-wook;Ro, Yun-sik;Ahn, Byong-kyu
    • Journal of the Korea Academia-Industrial cooperation Society
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    • 제17권9호
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    • pp.133-140
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    • 2016
  • The Ministry of Land, Infrastructure and Transport has introduced low-floor buses, which are convenient for passengers getting on and off the bus and for the handicapped. The standard bus model is 11 m long and uses compressed natural gas (CNG). However, this model has drawbacks in narrow rural road conditions such as those in farming and fishing villages and mountainous areas, as well as difficulty in refueling since CNG facilities are not readily available. In this study, running resistance values were obtained by coasting performance tests on actual roads using a Tata Daewoo LF-40 model with three different weight conditions: curb vehicle weight (CVW), half vehicle weight (HVW), and gross vehicle weight (GVW).The test methods include WHVC, NIER-06, and constant-speed driving at 60 km/h. These tests were used to measure the fuel economy of vehicles other than the target vehicles to obtain the combined fuel economy. The energy efficiency was highest in the case of CVW. In the WHVC mode, the fuel consumption rates of HVW and GVW were typically 3.5% and 12% higher than that of CVW, respectively. In constant-speed driving, the fuel efficiency of HVW was higher than that of CVW. Further research is required to analyze the exhaust gas data.

A Study on the Nurses' Contingent Employment and Related Factors (간호사의 비정규직 고용실태 및 관련요인에 관한 연구)

  • Choi, Sook-Ja
    • Journal of Korean Academy of Nursing Administration
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    • 제5권3호
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    • pp.477-500
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    • 1999
  • Korean labor market has showed remarkable change of the increase in the amount of unemployment and contingent employment since IMF bailout agreement. There is a theoretical position to explain this increase in contingent employment at hospitals with the notion of flexibility. The high flexibility of employment due to the increase of contingent employees is becoming very important part in new business strategy of hospitals. The types of contingent employment of the nurse are part-time employment temporary employment, fixed-term employment, and internship which was introduced in early 1999. Recently, Korean health care industry managers have paid attention to the customer oriented service, rationalization of business administration, service quality control so that they can adjust their business to outer environment. Especially their efforts concentrate on the wage reduction through efficient and scientific control of man power because wage shares about 40% of total cost. This dissertation aims at verifying the phenomena of the contingent employment of the nurse and analyzing the related factors and problems. To rephrase these aims in ordinal: First, verifying the phenomena of contingent employment of the nurse. Second, verifying the problems of that phenomena. Third, analyzing the related factors of the contingent employment of the nurse. To accomplish these research goals, a statistical survey was executed. in which 384 questionnaires-66 for manager nurses, 318 for contingent nurses - were given to nurses working at 66 hospitals-which have at least 100 beds-in Seoul. Among them, 187 questionnaires-38 from manager nurses, 149 from contingent nurses'- 'were returned. Then, the data coded and submitted to T-test, $X^2$ -test, variance analysis(ANOVA), correlation analysis, multiple regression analysis, Logistic Regression with SAS program. The research results of the contingent nurses are followings: 1. The average career term at the present hospital 8.4 months: duty-on days per month are 24.2 days: working time per day is 7.9 hours. These results showed little difference from regular nurses. 2. Their wage level is about 70% of regular nurses except for internship nurses whose wage level is 41% of regular nurses. To break down the wage composition, part-time nurses and internship nurses get few allowance and bonus. And contingent nurses get very low level of additional pay except for fixed-term nurses who are under similar condition of employment to regular nurses. These results show that hospital managers are trying to reduce the labor cost not only through the direct way of wage reduction but through differential treatment of bonus, retirement allowance, and other additional pay. 3. The problem of contingent employment: low level of pay; high level of turn-over rate: weakening of union; low level of working condition: heavy burden of work; inhuman treatment. The contingent nurses consider these problems more seriously than manager nurses do. What manager nurses regard problematic is the absence of feeling-belonged and responsibility of the contingent nurses. 4. The factors strongly related with the rate of the number of contingent nurses for the number of regular nurses; gross turn-over nurses; average in-patients per day; staring wage of graduate from professional college: the type of hospital ownership; the number of beds; the gap between gross newcomer nurses and gross turn-over nurses. The factors related with their gross wage per month; the number of beds; applying of health insurance; applying of industrial casualty insurance; applying of yearly-paid leave; the type of hospital ownership; average out-patients per day; gross turn-over nurses. The meaningful factors which make difference by employment type: monthly-paid leave; physiological leave. The logistic regression analysis using these two factors shows that monthly-paid leave is related with the type of hospital ownership; the number of beds; average out-patient per day, and physiological leave is related with the gross newcomer nurses; gross turn-over nurses; the number of beds.

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A Study of The Nursing Education Concerning Two Years Associate Degree Nursing Program (간호 교육에 대한 일 연구 -2년제 초급대학 과정 중심으로-)

  • 변창자
    • Journal of Korean Academy of Nursing
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    • 제4권3호
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    • pp.63-79
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    • 1974
  • 1. The purpose of this study. The purpose of this study is to plan and investigate short-term nursing education of two-years associate degree program to produce middle-level professional nurses which are needed by-society and nation. Current nursing education in Korea is divided into four years degree program, three years diploma program Even (though) there are differences in the aims of their education, the curriculums are not much different between the education for producing leaders which is its basic purpose and training middle-level professional nurses. Therefore the purpose of associate degree program lies in minimizing the waste of time and finance which are invested for long-term education for middle-level professional nurses. And also this coincide with the policy of national technical training and definite supply of nurse manpower according to health policy for effective role and ability of nurse. 2. The method of study. This is based on the study of literature, research on the actual condition and investigation of opinion- through questionnaire. L) The study of literature: Domestic and foreign literatures for two years associate degree program were studied and investigated. 2) Research on the actual condition : Current three years nursing education program was collected and analysed. 3) Investigation of opinion. The problem of curried nursing education system and the possibility of two years associate degree program were investigated through questionnaire. 3. The result of the study. 1) The trend of recent nursing education. a. The aims of nursing in past chiefly taking care of physical disease of patient has recently changed to nursing of character including physical, mental, socio-economic, educational and psychological condition. b. For the performing systematic and effective nurse's duty according to her role, the-change of educational system which is classified as a range of education the period of education and certificate after graduation has been enforced or fulfilled. c. Nursing education also has a trend to become a collage or two years associate degree program which can get same legal protection as other educational institutions whose basic purpose is education. Attached nursing school to hospital is getting disappeared because of disadvantage of educational system. 2) Problems. Depending upon research on actual condition of current 3 years nursing education program. a. There are too many subjects. b. Contents of education could be doubled because major subjects are subdivided in detail. c. The credits for graduation are too heavy comparing to the period of study or the ability of students. (The necessary credits are 150.8 for three years according to actual investigation 4. There is no certain standard in organizing curriculum therefore there are too much differences between schools. 4. Basic Plan. The plan for two years associate degree program in nursing education depending on demand of professional nursing field of society is based on following items. 1) Training middle-level professional nurse lay emphasis on liberal arts and basic major field. 2) Liberal arts are divided into required and optional subjects and students could take courses by choice. 3) Major subjects are compound together by fields and they become the sciences of nursing Ⅰ,Ⅱ,Ⅲ,Ⅳ and every items has its educational purposes and contents major study includes laboratory practice and clinical experience. 4) The required credits for graduation are to which means 17-18 credits a semester. The above has been planned to solve the problems of current three years nursing education program. In conclusion for the achievement of this system, following items are needed. 1) It is necessary to change educational administration and system such as amendment of educational law or order of educational application of law. 2) Qualified professors should be available to understand and develope the idea or purpose of this educational system. 3) Local medical institutions should be opened widely and educational for clinical training. 4) The job after graduation should he secured positively.

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