• Safety and Health at Work
• /
• 제5권4호
• /
• pp.175-180
• /
• 2014

Wet-work can be defined as activities where workers have to immerse their hands in liquids for >2 hours per shift, or wear waterproof (occlusive) gloves for a corresponding amount of time, or wash their hands >20 times per shift. This review considers the recent literature on wet-work exposure, and examines wet-work as a main risk factor for developing irritant contact dermatitis of the hands. The aim of this paper is to provide a detailed description of wet-work exposure among specific occupational groups who extensively deal with water and other liquids in their occupations. Furthermore, it highlights the extent and importance of the subsequent adverse health effects caused by exposure to wet-work.

• Journal of Mechanical Science and Technology
• /
• 제20권9호
• /
• pp.1475-1482
• /
• 2006

Wet compression means the injection of water droplets into the compressor of gas turbines. This method decreases the compression work and increases the turbine output by decreasing the compressor exit temperature through the evaporation of water droplets inside the compressor. Researches on wet compression, up to now, have been focused on the thermodynamic analysis of wet compression where the decrease in exit flow temperature and compression work is demonstrated. This paper provides thermodynamic and aerodynamic analysis on wet compression in a centrifugal compressor for a microturbine. The meanline dry compression performance analysis of centrifugal compressor is coupled with the thermodynamic equation of wet compression to get the meanline performance of wet compression. The most influencing parameter in the analysis is the evaporative rate of water droplets. It is found that the impeller exit flow temperature and compression work decreases as the evaporative rate increases. And the exit flow angle decreases as the evaporative rate increases.

• Nutrition Research and Practice
• /
• 제6권4호
• /
• pp.366-374
• /
• 2012

In order to create a worker-friendly environment for institutional foodservice, facilities operating with a dry kitchen system have been recommended. This study was designed to compare the work safety and work environment of foodservice between wet and dry kitchen systems. Data were obtained using questionnaires with a target group of 303 staff at 57 foodservice operations. Dry kitchen facilities were constructed after 2006, which had a higher construction cost and more finishing floors with anti-slip tiles, and in which employees more wore non-slip footwear than wet kitchen (76.7%). The kitchen temperature and muscular pain were the most frequently reported employees' discomfort factors in the two systems, and, in the wet kitchen, "noise of kitchen" was also frequently reported as a discomfort. Dietitian and employees rated the less slippery and slip related incidents in dry kitchens than those of wet kitchen. Fryer area, ware-washing area, and plate waste table were the slippery areas and the causes were different between the functional areas. The risk for current leakage was rated significantly higher in wet kitchens by dietitians. In addition, the ware-washing area was found to be where employees felt the highest risk of electrical shock. Muscular pain (72.2%), arthritis (39.1%), hard-of-hearing (46.6%) and psychological stress (47.0%) were experienced by employees more than once a month, particularly in the wet kitchen. In conclusion, the dry kitchen system was found to be more efficient for food and work safety because of its superior design and well managed practices.

• 한국정밀공학회지
• /
• 제27권1호
• /
• pp.11-17
• /
• 2010

This study investigates the non-traditional manufacturing process of dry wire electrical discharge machining (EDM) in which liquid dielectric is replaced by a gaseous medium. Wire EDM experiments of thin workpieces were conducted both in wet and dry EDM conditions to examine the effects of spark cycle (T), spark on-time ($T_{on}$), thickness of work pieces, and work material on machining performance. The material removal rate (MRR) in the dry wire EDM case was much lower than that in the wet wire EDM case. In addition, the thickness of workpiece and work-material were found to be critical factors influencing the MRR for dry EDM process. The relative ratios of spark, arc and short circuit were also calculated and compared to examine the effectiveness of processes of dry and wet wire EDM.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2005년도 제24회 춘계학술대회논문집
• /
• pp.237-242
• /
• 2005

가스터빈엔진에서 압축기가 사용하는 에너지는 터빈에서 생성하는 에너지의 $30-50\%$까지도 이르기 때문에 압축기의 일을 줄이는 연구는 가스터빈의 효율을 증가시키는 문제와 연관된 중요한 연구주제이다. 압축기의 일을 줄이는 한 가지 방법으로 압축기의 입구에 물입자를 분사하는 방법이 제안되었는데, 이 방법은 물입자가 증발하면서 압축기 출구의 온도를 낮추어서 결과적으로 압축과정에 소요되는 에너지를 줄일 수 있는 방법이다. 이전까지의 연구는 열역학적 해석에 집중하여 온도 및 일의 감소를 해석하거나, 실험에 근거하여 가스터빈의 성능변화에 집중되었다. 본 논문에서는 물분사의 영향을 마이크로터빈용 원심압축기에 적용하여 열역학적 해석 뿐 아니라 공력학적 해석을 수행하였다. 물을 분사할 경우 공기압축과정보다 임펠러 출구 유동각이 줄어들었으며, 증발율이 높을수록 유동각 감소가 증가하였고, 압력비가 낮을수록 유동각 감소가 증가하였다.

• 항공우주기술
• /
• 제4권1호
• /
• pp.18-24
• /
• 2005

가스터빈엔진에서 압축기가 사용하는 에너지는 터빈에서 생성하는 에너지의 30-50%까지도 이르기 때문에 압축기의 일을 줄이는 연구는 가스터빈의 효율을 증가시키는 문제와 연관된 중요한 연구주제이다. 압축기의 일을 줄이는 한 가지 방법으로 압축기의 입구에 물입자를 분사하는 방법이 제안되었는데, 이 방법은 물입자가 증발하면서 압축기 출구의 온도를 낮추어서 결과적으로 압축과정에 소요되는 에너지를 줄일 수 있는 방법이다. 이전까지의 연구는 열역학적 해석에 집중하여 온도 및 일의 감소를 해석하거나, 실험에 근거하여 가스터빈의 성능변화에 집중되었다. 본 논문에서는 물분사의 영향을 마이크로 터빈용 원심 압축기에 적용하여 열역학적 해석 뿐 아니라 공력학적 해석을 수행하였다. 물을 분사할 경우 공기압축과정보다 임펠러 출구 유동각이 줄어들었으며, 증발율이 높을수록 유동각 감소가 증가하였고, 압력비가 낮을수록 유동각 감소가 증가하였다.

• 한국펄프종이공학회:학술대회논문집
• /
• 한국펄프종이공학회 2002년도 춘계학술발표논문집
• /
• pp.76-84
• /
• 2002

Fracture toughness was considered as one of the good estimates of the paper break tendency of paper web in the press room. Paper break on the paper machine is caused by many factors such as paper machine irregular vibrations, impurities in the fiber furnish, shives, and so on. On the paper machine, the solid content of paper web is changing very rapidly from less than 1% to over 95%. We tried to measure the fracture toughness of paper web at different solid contents for providing the fundamental knowledge of paper break. Stretches of wet web were also measured and compared to the fracture toughness changes. Four different fiber furnishes (SwBKP, HwBKP, ONP, and OCC) were refined to different degrees, and at different solid contents (40%, 60%, 80%, and 95%), their fracture toughnesses were measured. Two fracture toughness measurement methods (essential work of fracture and Tryding's load-widening method) were used, and we found they gave identical results. The stretch curves of the wet webs against the axis of solid contents were very similar to the fracture toughness curves of those.

• 펄프종이기술
• /
• 제33권5호
• /
• pp.37-44
• /
• 2001

Fracture toughness was considered as one of the good estimates of the paper break tendency of paper web in the press room. Paper break on the paper machine is caused by many factors such as paper machine irregular vibrations, impurities in the fiber furnish, shives, and so on. On the paper machine, the solid content of paper web is changing very rapidly from less than 1% to over 95%. We tried to measure the fracture toughness of paper web at different solid contents for providing the fundamental knowledge of paper break. Stretches of wet web were also measured and compared to the fracture toughness changes. Four different fiber furnishes (SwBKP, HwBKP, ONP, and OCC) were refined to different degrees, and at different solid contents (40%, 60%, 80% and 95%), their fracture toughnesses were measured. Two fracture toughness measurement methods (essential work of fracture and Tryding's load-widening method) were used, and we found they gave identical results. The stretch curves of the wet webs against the axis of solid contents were very similar to the fracture toughness curves of those.

• 한국산업보건학회지
• /
• 제32권4호
• /
• pp.402-413
• /
• 2022

Objectives: In this study, the scale of exceeding the extreme heat exposure standard at the construction site was estimated using the nationally approved statistical data and wet bulb globe temperature modeling method. By comparing and analyzing the modeling results with the existing work environment monitoring results, the risk of heat exposure at outdoor construction sites was considered. Methods: Using the coordinates of second level administrative districts and meteorological observatories as the key, the automated synoptic observing system data and building permit data for 2021 were matched. The wet-bulb temperature was obtained using Stull's formula, and the globe temperature was obtained using the Tg_KMA2006 model. WBGT was calculated using these. Excess rates were obtained compared to exposure limits for heavy work-continuous work and moderate work-25% rest. It was compared with the results of the work environment monitoring in 2020. Results: As a result, 1,827,536 cases were estimated for 11,052 workplaces in one year. This is much higher than the 5,116 cases of 3818 workplaces of the existing work environment monitoring results. It is confirmed that the exposure limit was exceeded in 10.6~24.0% of the entire period and 70.2~84.1% of the peak period of the heat wave. It is very high compared to 0.9% of the existing work environment monitoring result. Conclusions: It is necessary to improve the system of monitoring and statistics related to extreme heat. Additional considerations are needed regarding WBGT estimation methods, meteorological data, and evaluation time. Various follow-up risk assessment studies for other industries and time series need to be continued.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
• /
• pp.926-929
• /
• 2007

A significant progress has been made in the characterization of zinc oxide (ZnO) semiconductor as a new semiconductor layer instead of amorphous Si semiconductor used in thin film transistor due to its high electron mobility at low deposition temperature which is quite suitable for flexible display and OLED devices. The wet pattering of ZnO is another important issue with regard to mass production of ZnO thin film transistor device. However, the wet behavior of ZnO thin film in aqueous wet etching solutions conventionally used un TFT industry has not been reported yet, in this work, wet corrosion behavior of RF magnetron sputtered ZnO thin film in various wet solutions such as phosphoric and nitric acid solutions was studied using by electrochemical analysis. The effects of deposition parameters such as RF power and oxygen partial pressure on corrosion rate are also examined.