• Journal of Mechanical Science and Technology
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• 제17권3호
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• pp.422-428
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• 2003

This study concerns the performance of the heat transfer of the thermosyphons having 60, 70, 80. 90 axial internal low-fins in which boiling and condensation occurr. Water, HCFC-141b and CFC-11 have been used as the working fluids. The operating temperature, the liquid charge ratio and the inclination angle of thermosyphons have been used as the experimental parameters. The heat flux and heat transfer coefficient at the condenser are estimated from experimental results. The experimental results have been assessed and compared with existing theories. As a result of the experimental investigation, it was found that the maximum heat flow rate in the thermosyphons is dependent upon the liquid charge ratio and inclination angle. A relatively high rate of heat transfer has been achieved by the thermosyphon with axial internal low-fins. The inclination of a thermosyphon has a notable influence on the condensation. In addition, the overall heat transfer coefficients and the characteristics at the operating temperature are obtained for the practical applications.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.1642-1646
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• 2011

One of the rolling stocks, low floor tram is recognized as the important alternative to improve traffic and environmental problems. There are many advantages of tram transportation system. It has, especially, low construction costs and easy accessibility. Trams operate with vehicles on roadways. The bogie configuration including traction motor of tramcar is different from that of conventional electric trains because tram has lower floor than train. In these reasons, the traction motors of tramcar are exposed to dusts, water and so on. Therefore, motors are designed by totally enclosed type. In this paper, we explain the design and test of totally enclosed traction motor for tramcar. Characteristic tests and temperature-rising tests were carried out in order to predict the performance of motor and the maximum temperature of coil.

• International Journal of Concrete Structures and Materials
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• 제2권2호
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• pp.83-90
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• 2008

Permeability to vapor and water among other performances required for finishing materials is dealt with in this study. The relative moisture content of concrete coated/covered with a finishing material was experimentally investigated while changing the environmental conditions including temperature, relative humidity, and rainfall. An organic paint (water-based urethane), organic synthetic resin emulsion-type film coating (film coating E), and inorganic porcelain tiles were selected as the finishing materials. When compared from the aspect of vapor and water permeability, the vapor permeability and water permeability of water-based urethane were high and low, respectively; those of film coating E were high and high, respectively; and those of porcelain tiles were low and low, respectively. This means that the moisture state of concrete structures is governed not only by the environmental conditions but also by the performance of finishing materials. It is therefore of paramount importance to appropriately select a finishing material to address the specific deteriorative factors involved in the concrete structure to be finished.

• 동력기계공학회지
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• 제15권2호
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• pp.25-30
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• 2011

A fresh water generation system is designed for converting brackish water or seawater into fresh water. In this paper fresh water generation by distillation process that evaporates feed water and subsequently condenses vapor as evaporation product to get fresh water was studied and city water was employed as feed water. The system uses the ejector to create a vacuum, under which liquid can be evaporated at lower temperature than it at normal or atmospheric condition, hence less energy consumption. The effect of various operating conditions i.e. temperature of feed water and different orifice diameters were studied experimentally to investigate the characteristic of the system. It was found that these parameters have significant effect in the performance of fresh water generation system with low pressure evaporation.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.368-371
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• 2008

An extensometer system to measure strain and displacement of cylindrical fatigue specimen in a autoclave of high temperature and high pressure environment has been developed by KEPRI. The extensometer reads the displacement caused by fatigue loads at the target length of the specimen installed inside the autoclave. The performance of the extensometer were tested at 15MPa, $315^{\circ}C$ of a operating pressurized water reactor. Two LVDT's of magnet type were connected to the extensometer and used for converting the fatigue displacement to electronic signal. The device is being used for developing environmental fatigue curve of CF8M cast austenitic stainless steel (CASS) in the test condition of low cycle and low strain. This paper introduces the background and results of the development.

• 한국정밀공학회지
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• 제27권5호
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• pp.14-21
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• 2010

In this study, presintered low purity alumina ceramics were machined with various tools to clarify the effects of the tool material, cutting condition and tool geometry on machinability. The main conclusions obtained were as follows. (a)The wear of tungsten carbide tool becomes smaller with the increase of the feed and clearance angle, and with the decrease of rake angle, especially exhibiting considerably smaller wear with both the decrease of rake angle and the increase of clearance angle. (b) So far as turning the ceramic presintered at low temperature, the diamond tool shows the best performance with higher feed. (c) The effect on the tool wear of the feed, clearance angle and rake angle becomes smaller in turning the ceramic presintered at higher temperature. (d) The tool wear is not severely affected by the depth of cut.

• 한국전기화학회:학술대회논문집
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• 한국전기화학회 2004년도 전지기술심포지움
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• pp.75-108
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• 2004

The market, development and trend of Lithium ion Batteries in China are introduce briefly. Early, Chinese manufactories were busy to expand and many new battery factories have been built up. Now, the relatively large companies pay more attentions on comprehensive quality improvement, therefore the production processing and facilities have been also modified in some extent. The recent technology progresses focus on High capacity (energy density), High rate, High average voltage, High safety, High temperature properties, Long cycle life, Low temperature properties, Low self discharge, Low cost, Super-large, Super-small, Super-thin, Consistency, Customization, and Environment friendly processing, simply $H_5L_4S_3C_2E_1$. Lithium ion polymer batteries which all batteries packaged with soft lamination film are named as in China have a quick growth and emphasized here because of their advantages ins $H_5L_4S_3C_2E_1$ for which it is quite difficult to be realized at the same time. Some of research works such as listed above are introduced. The other contends related to application trend of Lithium ion batteries and projects carrying out are also included.

• Structural Engineering and Mechanics
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• 제52권3호
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• pp.613-632
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• 2014

In the early design stage of ships, the two most important structural analyses are performed to identify the structural capacity and safety. The first step is called global strength analysis (longitudinal strength analysis or hull girder strength analysis) and the second step is local buckling analysis (stiffened panel strength analysis). This paper deals with the ultimate strength performance of Arctic Sea Route-going commercial ships considering the effect of low temperature. In this study, two types of structural analyses are performed in Arctic sea conditions. Three types of ship namely oil tanker, bulk carrier and container ship with four different sizes (in total 12 vessels) are tested in four low temperatures (-20, -40, -60 and $-800^{\circ}C$), which are based on the Arctic environment and room temperature ($20^{\circ}C$). The ultimate strength performance is analysed with ALPS/HULL progressive hull collapse analysis code for ship hulls, then ALPS/ULSAP supersize finite element method for stiffened panels. The obtained results are summarised in terms of temperature, vessel type, vessel size, loading type and other effects. The important insights and outcomes are documented.

• Fisheries and Aquatic Sciences
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• 제22권10호
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• pp.23.1-23.10
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• 2019

Background: Taurine is a conditional essential amino acid for fish. A study was conducted to investigate the compensating effect of supplemental taurine in diets for red seabream (Pagrus major) on impaired growth performance by fish meal (FM) replacement with soybean meal (SM) at low water temperature (14.15 ± 1.95 ℃). Methods: A FM-based diet was considered as a high FM diet and three other experimental diets were formulated to replace FM with SM by 20, 35, or 50% (HFM, SM20, SM35, or SM50, respectively) without taurine and other four diets were formulated by adding 1% taurine to the diets (HFM-T, SM20-T, SM35-T, or SM50-T, respectively). Triplicate groups of fish (108.9 ± 1.58 g/fish) were distributed into 24 polyvinyl circular tanks (215 L) with 20 fish per tank and fed one of the diets to satiation for 20 weeks. Results: Growth performance and feed utilization of red seabream were significantly improved by the dietary taurine supplementation. SM20-T and SM35-T diets increased fish growth that are comparable to HFM diet. Feed intake, feed conversion ratio, and protein efficiency ratio of fish fed SM20-T and SM35-T diets were not significantly different from those of HFM group. Dietary taurine supplementation in each FM replaced group numerically increased innate immunity of the fish. Lysozyme and superoxide dismutase activities were significantly decreased in fish fed SM35, SM50, and SM50-T diets compared to those of fish fed HFM diet while they were not significantly lower in SM20, SM20-T, SM35, and SM35-T groups. Glutathione peroxidase activity was significantly lower in fish group fed SM50 diet while SM50-T group did not significantly lower compared to that of HFM group. The relative expression level of hepatic IGF-1 mRNA was improved in fish fed taurine-supplemented diets compared to their respective SM diets. Conclusions: Growth performance and feed utilization of red seabream can be accelerated or restored by 1% taurine supplementation when they are fed high level of SM up to 35% in diets during low water temperature season.

• 전기학회논문지
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• 제66권7호
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• pp.1141-1148
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• 2017

Generally, a thermistor made by sintering a metal oxide is widely used to measure the ambient temperature. This thermistor is widely used not only for industrial use but also for medical use because of its excellent sensitivity, durability, temperature change characteristics and low cost. In particular, the normal body temperature is 36.9 degrees relative to the armpit temperature, and it is most closely related to the circulating blood flow. Previous studies have shown that body temperature changes during biomechanical changes and body temperature changes by anomalous signs or illnesses. Therefore, in this study, we propose a Lock-In-Amp design to detect minute temperature changes of clothing and thermistor wired by a preacher as a method to regularly measure body temperature in daily life. Especially, it is designed to measure the minute resistance change of the thermistor according to body temperature change even in a low-cost microprocessor environment by using a micro-processor-based Lock-In-Amp, and a jacquard and the thermistor is arranged so as to be close to the side, so that the reference body temperature can be easily measured. The temperature was measured and stored in real time using short-range wireless communication for non - restraint temperature monitoring. A baby vest was made to verify its performance through temperature experiments for infants. The measurement of infant body temperature through the existing skin sensor or thermometer has limitations in monitoring infant body temperature for a long time without restriction. However, it can be overcome by using the embroidery fabric based micro temperature monitoring wireless monitoring device proposed in this study.