• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.5
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• pp.430-436
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• 2014

The mission objective of STEP Cube Lab. (Cube Laboratory for Space Technology Experimental Project) classified as a pico-class satellite is to verify the technical effectiveness of payloads such as variable emittance radiator, SMA washer, oscillating heat pipe and MEMS based solid propellant thruster researched at domestic universities. In addition, the MEMS concentrating photovoltaic power system and the non-explosive holding and separation mechanism with the advantages of high constraint force and low shock level will be developed as the primary payloads for on-orbit verification. In this study, the feasibility of the mission actualization has been confirmed by the preliminary system design.

• Journal of Food Hygiene and Safety
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• v.34 no.6
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• pp.571-575
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• 2019

Fungal occurrence during production of dried red pepper was investigated using red pepper samples collected at harvest, before and after washing, and before, during or after drying. Fungal incidence was evaluated by counting the number of fungal colonies grown after incubating random pepper cuts on potato dextrose agar plates. Washing with ground water had no significant effect on reduction of fungal contamination. Fungal increase was observed in some samples, and the insides of washer and containers were contaminated with fungi. Drying caused significant fungal increase regardless of drying method although the fungal incidence after machine drying was lower than that after greenhouse drying. Fungal increase was observed in the samples being dried in a greenhouse and some mycotoxigenic species were also detected. Therefore, the most important control point for fungal contamination during dried pepper production appears to be the drying process, especially in a greenhouse.

• Journal of Korean Society of Steel Construction
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• v.9 no.2 s.31
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• pp.171-179
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• 1997

The high-tension bolted joints are clamped by the axial force which approaches the yielding strength. The introduced axial force is transmitted to the connection members pass through washer. The transferred load in connections is balanced to the compressive stress of plates, axial force in bolts and the external loads. In this mechanism, the compressive stress and slip load we dominated by the effective stiffness of bolted joints and plates. In general the effective stiffness is specified to product to the effective area and elasticity modulus in connections. In this reason, the conic projection formular which is assumed that the axial force in bolts is distributed to the cone shape and that region is related to the elastic deformation mechanism in connections, was proposed. But it conclude what kind of formula is justified. Therefore in this paper, the fatigue tests are performed to the high tension bolted joints and inspected to the phase on the friction face. And using the FEM and numerical method, it is analyzed and approximated to the compressive stress distribution and its region. Moreover, it is estimated to the effective area and to the relation the friction area to the effective compressive distribution region.

• Clinics in Shoulder and Elbow
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• v.9 no.2
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• pp.189-195
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• 2006

Purpose: To analyze the result of the accurate open reduction of acromioclavicular (AC) joint and pin fixation, coracoclavicular (CC) screw fixation without CC ligament repair for AC joint injuries. Materials and Methods: Between January 2000 and December 2003, seventeen cases with at least one year follow-up among twenty-one cases underwent operation for AC-CC ligament injuries. A transverse incision approximately 5 cm in length was made over the clavicle, and the AC joint was reduced accurately. Under the image intensifier, a cannulated screw and washer were inserted for the CC ligament. Two Steinman pins were inserted for the AC joint and the AC ligament was repaired with nonabsorbable suture. Gentle passive range of motion was begun postoperative 2 weeks. The pins were removed at $6{\sim}8$ weeks and the screw was removed at $10{\sim}12$ weeks. The results were evaluated by a distance between AC and CC joints on plain films and ASES score at last follow-up. Results: At the last follow-up, there was no limitation of motion and average ASES score was 96($86{\sim}100$ points). There was no failure showing over 5 mm difference of distance compared to opposite side on the plain films. Seven cases had the skin damages and local infection due to pin migration and three cases showed the loosening of CC screw. Conclusion: We could have satisfactory results by accurate reduction of AC joint and simple pins and screw fixation for AC-CC ligament injuries.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.4032-4038
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• 2014

Vegetable fatty acid solid soap requires a drying process for moisture evaporation and hardness after being manufactured through saponification. Although the soap is manufactured by mixing additives mainly from natural ingredients, existing studies have focused primarily on the usability of vegetable solid soap. Consequently, research into the physical properties of vegetable fatty acid solid soap mixed with natural ingredients has been unsatisfactory. Therefore, this study attempted to compare and observe the changes in the physical properties (pH, surface tension, critical micelle concentration, and cleansing power) of solid soap in accordance with the drying period and additives (tea tree E.O and $TiO_2$) using pH paper, the Du Nouy measurement method, sedimentation method, and ultrasound washer. Regardless of the mixture with additives, vegetable fatty acid solid soap showed the same pH, and there was no change in the pH while maintaining pH 8 beginning from the $2^{nd}$ weeks to $12^{th}$ weeks of drying. In addition, as a result of measuring the surface tension and CMC, regardless of the drying period, only the soap added with $TiO_2$ showed an even value of 62.5mg/L, whereas the other soap specimens showed a decline in CMC to 25mg/L on the fourth week of drying. As a result of measuring the detergency, the removal efficiency of vegetable fatty acid solid soap mixed with tea tree E.O and $TiO_2$ and dried for four weeks was 4.50~4.65%, which was higher than that of the vegetable fatty acid solid soap without additives (3.62~3.92%).

• Korean Journal of Construction Engineering and Management
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• v.6 no.5 s.27
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• pp.186-192
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• 2005

The purpose of this study is to find the reality of environmental management cost in construction projects and to suggest some policies in order that owners appropriate the environmental management cost reasonably in the construction budget for reducing the environmental pollution at job sites. We surveyed the actual state of appropriating and expending the environmental management cost over 122 construction sites. According to the results of the survey, while the appropriated rate of the environmental management cost was 0.59% of the total construction cost. the expended rate reached at 0.94%. When examining the antipollution facilities which were operated in job sites, the investment for equipment against air-pollution such as tire washer, dust-proof device was relatively higher than other antipollution equipment. As the method appropriating the environmental management cost, we concluded that a quantity-per-unit costing method is more reasonable than appropriating at a fixed rate of total construction cost considering that there is little correlation between total construction cost and the environmental management cost. To do so, antipollution facilities that must be examined at a design or estimation stage of a construction project should be prescribed by the law. Moreover, referenced cost data for the quantity-per-unit costing should be prepared and officially published.

• Journal of the Korean Arthroscopy Society
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• v.7 no.2
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• pp.183-188
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• 2003

Purpose : The purpose of this study is to evaluate the results of revision surgery for failed anterior cruciate ligament (ACL) reconstruction using quadruple hamstring tendon autograft. Materials and Methods : From May 2000 to July 2002, six patients received ACL revision surgery using quadruple hamstring autograft for failed ACL reconstruction. Femoral tunnels were made 40 mm in depth and fixed with a cross pin and a bioabsorbable interference screw to fill the bone defect. In tibial tunnels, the grafts were fixed with Intrafix(Mitek, Norwood, MA). In case of tibial tunnel widening, additional screw-washer fixation was done. Follow up was at least 12 months postoperatively. Clinical assessments consisted of Lysholm knee scores, International Knee Documentation Committee(IKDC) evaluation form and manual maximal side to side difference using KT-2000 arthrometer. Results : The average Lysholm knee score improved from 77.2 preoperatively to 87.7 postoperatively. At the final IKDC evaluation, 1 case was graded as normal, 4 nearly normal, 1 abnormal. Mean side to side difference of manual maximum anterior displacement using the KT-2000 arthrometer was 1.8mm. The success rate was $83\%$. Conclusion : ACL revision surgery using quadruple hamstring autograft with double fixation is considered good procedure with successful results.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.12
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• pp.1249-1255
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• 2011

In modern large-scale semiconductor manufacturing clean rooms, the energy consumed by the outdoor air-conditioning system during heating, humidification, cooling, and dehumidification of the incoming outdoor air represents about 45% of the total air-conditioning load required to maintain a clean-room environment. In particular, the energy required for humidification of the outdoor air in winter is very high. Therefore, evaluation and comparison of the energy consumption in key humidification systems, viz., steam-humidification and water-spray-humidification systems, used in outdoor air-conditioning systems would be useful to reduce the outdoor air-conditioning load in clean rooms. In the present study, an experiment with an outdoor air flow of 1000 $m^3$/h was conducted to compare the air-conditioning process and energy consumption in outdoor air-conditioning systems with electrodeboiler steam humidifiers and air-washer water spray humidification systems. The experimental results showed that the water-spray-humidification-type outdoor air-conditioning system consumed less electrical power than did the steam-humidification-type system and was more energy efficient during winter.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.2
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• pp.54-63
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• 2014

Corrugated steel plate structure, which is built by assembling corrugated steel plate segments with bolts on site and filling the surroundings with quality soil, is widely used for buried structures as a eco-corridors, small bridges, and closed conduits. This experimental study is dealt with the static and fatigue performance of bolt connected corrugated steel plates under flexural loading. The experimental variables to verify the fatigue performance are bolt diameters and detailing of connection such as washer and the corrugation dimension of specimens has a $400{\times}150$ mm. The experimental ultimate strength of specimens under static loading was higher than the theoretical strength and all specimen failed by a bearing and tearing failure of bolt hole of upper plate. Therefore, a fatigue tests of specimens had 6.0mm and 7.0mm thickness was conducted in which the load range was up to 209kN and 516kN, respectively. From the fatigue test, failure patterns are changed from plate bearing and tearing which is a typical failure pattern of static failure to a bearing failure of plate and shear failure of bolt, and experimental fatigue limit at $2{\times}10^6$cycles is about 85MPa.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.9
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• pp.1027-1033
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• 2011

A VCM sheet is a metal sheet on which PET/PVC is coated for outer panels of home appliances. The purpose of this study is to obtain methods for suppressing PET tearing that occurs during the press forming of the VCM sheet. In order to identity the factors that minimize PET tearing, an FE analysis was performed. The occurrence of PET tearing cannot be predicted using the conventional forming limit diagram. PET is torn by friction between a die and sheet, which is caused by the thickening of material at a die corner. To reduce the thickening of material, the blank shape was re-designed and the thickened material at a flange was removed by a trimming process. The results of the FE-analysis involving modified process parameters showed that the thickness of the product at a die corner is distributed within the clearance of drawing and flangeforming process. A forming experiment was conducted to verify the proposed process parameters. A good final product was obtained without PET tearing of the VCM sheet.