• Korean Journal of Food Science and Technology
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• v.31 no.5
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• pp.1196-1202
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• 1999

This work was to determine the microbial and physico-chemical changes of HTST-pasteurized soymilk using microwave energy. Soymilk was HTST pasteurized$(at\;90^{\circ}C\;for\;20\;sec)$ by three methods: by heating in a stainless steel tube immersed in a hot water bath(MP0), by heating in a microwave cavity to a defiled temperature and then holding in a hot water bath(MP1), and by both heating and holding in a microwave cavity(MP2). The microbial quality based on the total plate count was in the order of MP0, MP2 and MP1. The three samples pasteurized by different methods showed the similar microbial quality with respect to the coliform count, psychrotrophic bacterial count and phosphatase activity. The destruction of trypsin inhibitor was in the order of MP0, MP1 and MP2. There were no significant differences in pH, titratable acidity, viscosity and vitamin $B_2$ content before and after pasteurization and among the different pasteurization methods. The similar or higher quality retention of the MP1 or MP2 supports the possibility of using microwave energy for the HTST pasteurization of soymilk and other fluid food products.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.17 no.3
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• pp.319-332
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• 2004

Due to their high strength to weight ratios and excellent durability, fiber reinforced polymer(FRP) is widely used in construction industries. In this paper, a shape optimum design of FRP bridge decks haying pultruded cellular cross-section is presented. In the problem formulation, an objective function is selected to minimize the volumes. The cross-sectional dimensions and material properties of the deck of FRP bridges are used as the design variables. On the other hand, deflection limits in the design code, material failure criteria, buckling load, minimum height, and stress are selected as the design constraints to enhance the structural performance of FRP decks. In order to efficiently treat the optimization process, the cross-sectional shape of bridge decks is assumed to be a tube shape. The optimization process utilizes an improved Genetic Algorithms incorporating indexing technique. For the structural analysis using a three-dimensional finite element, a commercial package(ABAQUS) is used. Using a computer program coded for this study, an example problem is solved and the results are presented with sensitivity analysis. The bridge consists of a deck width of 12.14m and is supported by five 40m long steel girders spaced at 2.5m. The bridge is designed to carry a standard DB-24 truck loading according to the Standard Specifications for Highway Bridges in Korea. Based on the optimum design, viable cross-sectional dimensions for FRP decks, suitable for pultrusion process are proposed.

• Explosives and Blasting
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• v.33 no.3
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• pp.21-28
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• 2015

The objective of this study is to develop a method for monitoring continuously the combustion propagation behavior of commercial thermite reaction mixtures using conventional continuous VOD (velocity of detonation) system. In order to monitor the combustion front propagation with elapsed time during thermite reaction, the VOD system employs two types of commercial VOD probes and one self-made probe: VOD PROBEROD-OS, VOD PROBEROD-HS and VOD PROBEROD-ES, respectively. Among the probes, the only self made VOD PROBEROD-ES successfully demonstrates the velocity of combustion propagation (VOC) with elapsed time. It was found that VOC of the thermite reaction mixture inside a steel tube has been reached around 200m/s within 100mm distance from the ignition and dramatically increased up to about twice the speed of sound in the range between 100mm and 300mm distance. Finally the VOC reached up to around 800m/s. This results imply that it is necessary to use over 300mm long cartridge of thermite reaction mixture in order to achieve normal VOC of the mixture.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.3
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• pp.965-975
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• 2014

Pretension PSC (Prestressed Concrete) members are subjected to a certain limit of size as they are generally produced in the off-site plant and transferred to the site due to the large scale of the product on system. In this study, a portable pretensioning production system has been developed, which allow us to apply the pretension method on site. Considering that a 50m span PSC girder using the pretension method requires a pressing device to endure a large jacking force, the portable pretension production system has to ensure safety against such a large pretension jacking force. In this study, the portable pretensioning system to produce a 50m span pretension girder was manufactured by using CFT (Concrete Filled steel Tube) members. In order to understand the stability of the system and the behavior of the elements, a static loading test was conducted and the stability of the proposed portable pretensioning production system was confirmed. The developed portable pretension system was applied to several construction sites and was investigated the problems on site. During the pretension girder and slab members that was producted by this pretension system in construction site, it has be found the several advantages such as simple fabrication processes, reduction of prestress-loss, and a decrease of 15% compared with the fabrcation cost of post-tension girder. After due consideration of the problems, this portable pretension system will be improved.

• International Journal of Highway Engineering
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• v.8 no.2 s.28
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• pp.1-12
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• 2006

An existing Steel pipe, Cast iron pipe and Concrete pipe is can not escaped from aging, specially Metal tube is causing many problems that the quality of water worse is concerned about many rust and mike efficient use of preservation of water. The use of Glassfiber Reinforced Plastic Pipe(GRP PIPE) should be one of the possible scheme to get over these problems. The GRP PIPE has an excellent resistance power and the life is lasting from 50 to 100 years roughly. It's to be useful as a result of high durability and a good construction work also it is a light weight therefore can be expected to short the time of construction and man power. In this research, to executed the small-scaled model test, in-situ model test using CLSM of in-situ soil and to evaluated the stress - strain of the pipe also try to estimated how useful is. From the model test in laboratory, the vertical and horizontal deformation of the GRP PIPE measured in six instance using 200mm and 300mm in diameters. The value of experimentation, theory, analysis got the same results of the test, but the vertical and horizontal deformation gauged in small and the earth pressure was almost zero using CLSM of in-situ soil..

• Fire Science and Engineering
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• v.30 no.4
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• pp.121-127
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• 2016

This study analyzed the structural and electrical characteristics of an iron fittings type Corrugated Stainless Steel Tubing (CSST) damaged by the Primary Current Injection Test System (PCITS). CSST consists of cladding, tube, nuts, clamp ring, flare cap, socket, and ball valve. For an evaluation of the dielectric withstand voltage, the area between the live part and non-live part of the CCST shall withstand a voltage of 220 V AC for one minute. For an evaluation of the insulation performance by 500 V DC, it is required that the insulation exceed more than $1M{\Omega}$ before the temperature rise test, $0.3M{\Omega}$ after the test. Although the average resistance of the product was $11.5m{\Omega}$, that of the product damaged at a current of 130 A by the PCITS was $11.50m{\Omega}$. Furthermore, parts of the cladding were melted and black smoke appeared when a current of 130 A applied for 10 s. After 60 s, most parts were heated and turned red. At 120 s, the parts that turned red had widened. Although it did not form a normal distribution because the P value was 0.019 with a confidential interval of 95%, it revealed outstanding characteristics with an AD (Anderson-Darling) value of 0.896 and a standard deviation of 0.5573.

• Analytical Science and Technology
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• v.14 no.3
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• pp.274-285
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• 2001

In this study, the thermal desorption-cryofocusing-gas chromatographic(TD-C-GC) method was developed for determination of volatile organic compounds(VOCs) in ambient air and was applied at the municipal solid waste landfill sites. On-column cryofocusing was possible only with a 100 ml dewars bottle in TD-C-GC method with a stainless steel column. However, high operating pressure was needed for purging VOCs from the absorbent trap, which was able to solve by pressure programming with a electric pressure controller. By using both pressure and temperature programming brought increasing of resolution power in on-column cryofocusing method, but the high pressure caused a leakage of sample tube with repeated use. A loop cryofocusing devise was also developed and compared with the direct on-column method. In loop cryofocusing method, VOCs were concentrated on a 0.8mm i.d. loop which is located between the injector and separation column by using liquid nitrogen. In order to purge VOCs from the absorbent trap, only 0.4 psi of pressure was need in the loop cryofocusing method. Dual detection system was applied for the analysis of VOCs; a FID was used for hydrocarbons and a FPD was used for sulfur-containing compounds. Qualitative analysis was done by on-column cryofocusing GC-MS system. Among the large number of VOCs, toluene was the most abundant. Hydrogen sulfide, dimethyl sulfide, carbon disulfide, dimethyl disulfide and methyl propyl disulfide were detected at landfill site by FPD.

• Progress in Medical Physics
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• v.14 no.2
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• pp.99-107
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• 2003

This study was performed to prepare the verification film for localizing beam-target position with the Photon Knife radiosurgery system (PKRS) using linear accelerator(Mitsubishi, Model ML-15MDX). We developed a laser calibration system using a reticle of transparent lucite to detect Inlet and outlet beams. We verified fixation of the second collimator with film mounted on a holder in the shape of an octagon block 5cm apart from the isocenter. The film was exposed to photon beams of linear accelerator at an interval of 45 degrees during the gantry movement. There were no shifts in the beam of the second collimator during gantry movement. We used a position marker which is designed a head-shaped small lead block and a 10 mm in diameter of steel bead in the plastic tube. The position marker helped to verify the beam directions with patient position in multi-arc and trans-multi-arc of PKRS The verification of beam alignments showed an average 0.8$\pm$0.26 mm discrepancy in LINAC-gram images of PKRS. In our study, the couch movement was $\pm$5 mm laterally, while it shook $\pm$ 2 mm toward the couch axis. The couch, however, was immediately returned to the initial site after shaking. Thus, we postulate that the beam-target position(s) should be verified with LINAC-gram in a stereotactic radiosurgery system to achieve the accuracy of beam-target alignment.

• Korean Journal of Materials Research
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• v.9 no.10
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• pp.1018-1024
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• 1999

The effects of operating temperature and stress on degradation of components in high temperature steam generator were investigated. Several 2.25CrlMo tubes which had operated over 20 years and an unused 9CrlMoVNb tube were tested. For the former samples, the amount of $\textrm{M}_{6}\textrm{C}$ carbide and its size are increased with the aging or operating time. The precipitation behavior of carbides ($\textrm{M}_{2}\textrm{O}$, $\textrm{M}_{6}\textrm{C}$) is changed with the operating temperature of the tubes. However, unused 9CrlMoVNb samples show a different carbide precipitation process due to high chromium, vanadium, and niobium contents. The amount of Cr-rich $\textrm{M}_{23}\textrm{C}_{6}$ carbide is significantly increased with aging time, but that of $\textrm{M}_{6}\textrm{C}$ type carbide is rarely changed with aging time at elevated temperatures.

• The Journal of Korea Assosiation for Disability and Oral Health
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• v.12 no.2
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• pp.87-91
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• 2016

Pierre Robin syndrome (PRS) is characterized by the triad of congenital mandibular hypoplasia, glossoptosis and cleft palate. Infant PRS patients are frequently suffering from upper airway obstruction, gastroesophageal reflux and growth retardation caused by above mentioned problems. We report a dental caries treatment of 3-year old girl with Pierre Robin syndrome with multiple caries. The cause of multiple caries was mainly presumed as patient's eating habit caused by her general condition. She had some feeding problems and had history of gastric tube. She was still using milk bottle and took more than an hour to finish a meal. The treatment was performed under general anesthesia considering patient's condition; mild autism, poor cooperation and respiratory problem due to micrognathia. Severely affected upper incisors were treated with pulp treatment and restored with zirconia crown for esthetic purpose. Lower incisors were treated with pulp treatment and restored with composite resin. Upper right first primary molar was restored with stainless steel crown and other primary molars were treated with composite resin. There were no postoperative complications. According to her parents, the patient's compliance to oral hygiene management was greatly improved after the treatment since she was very pleased with the esthetic result and highly motivated by her looks. The treatment without sedation or general anesthesia would be possible once the airway is improved as the mandible grows.