• Journal of Food Hygiene and Safety
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• v.37 no.4
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• pp.225-231
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• 2022

In this study, the conditions of dry heat treatment (21 days at 65℃, 16 days at 70℃, 10 days at 75℃, and 7 days at 80℃) were investigated to inactivate Bacillus cereus ATCC 12480, Listeria monocytogenes ATCC SSA81, Staphylococcus aureus ATCC 6538, Escherichia coli O157:H7 ATCC 43894, and Salmonella Typhimurium ATCC 14028 on alfalfa seeds, without affecting the rate of germination of seeds. Alfalfa seeds were inoculated at levels of 6-7 log CFU/g and treated with dry heat at 65℃, 70℃, 75℃, and 80℃; thereafter, the rate of seed germination was determined. The rate of germination was set at 70%, according to the market standards. The bacteria were inactivated when B. cereus was treated with dry heat for 21 days at 65℃, 18 days at 70℃, 14 days at 75℃, and 4 days at 80℃; L. monocytogenes was treated for 21 days at 65℃, 18 days at 70℃, 12 days at 75℃, and 7 days at 80℃; S. aureus was treated for 18 days at 65℃, 18 days at 70℃, 11 days at 75℃, and 4 days at 80℃; E. coli O157:H7 was treated for 21 days at 65℃, 18 days at 70℃, 12 days at 75℃, and 6 days at 80℃; and Sal. Typhimurium was treated for 24 days at 65℃, 22 days at 70℃, 14 days at 75℃, and 7 days at 80℃. For all bacteria, the D-value (R² = 0.5656-0.7957) significantly decreased when the temperature increased from 65℃ to 80℃ (P<0.05). Since dry heat treatment of alfalfa seeds at 80℃ for 7 days affects their germination rate, dry heat treatment at 75℃ for 14 days is the most effective way to ensure their safety. This study suggests a potential method of bacterial inactivation using dry heat treatment to increase the microbiological safety of sprouts.

• Journal of Ship and Ocean Technology
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• v.6 no.4
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• pp.19-76
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• 2002

The author was appointed by the UK Department of Transport as a fellow Assessor with R. A. Williams during Lord Donaldson's Assessment (1995) of the loss of the OBO ship DERBYSHIRE and in 1996 as a UK Assessor for the planning and surveys of the wreck. He relinquished his appointment in October 1997 and was not thereafter Involved in the review and analysis of data gathered. This paper may be considered to be complementary to the reports of the UK and EC Assessors (Williams and Torchio, 1998a and 1998b) which followed that review and analysis. The paper deals with the history and loss of the ship, Including the concept developed in 1995 of 13 possible loss scenarios in a formal safety Risk Matrix of probability and seriousness. It analyses abnormal wave effects on hatch cover collapse, on ship bending, and on flooding of bow spaces and no. 1 hold. The implosion-explosion mechanics during sinking is outlined to explain the devastation of the wreck. The 1996 and 1997 underwater surveys are outlined as are the findings of fact. Each of the final 14 loss scenarios is analysed in the light of the firm and circumstantial survey evidence, plus many other factors of survey experience, analyses and experiments. The updated Risk Matrix speaks for itself and leads to the prime conclusions and major recommendations.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2013.04a
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• pp.163-163
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• 2013

최근의 수많은 산업 현장에서 취급하고 있는 각종 화학물질은 잠재적 위험성이 크므로 보관, 수송 및 취급할 때 특별한 주의가 필요하다. 공정 설계 시 정확하지 않은 폭발한계를 사용함으로서 사고가 유발되는 경우가 많다. 따라서 사업장에서 사용되고 있는 화학물질의 화재 및 폭발 특성치인 인화점, 폭발한계 등을 정확히 파악하는 것은 중요하다. 인화점은 하부인화점과 상부인화점으로 나누고 있고 있으며, 인화점은 가연성 액체의 화재 위험성을 나타내는 지표로써, 가연성액체의 액면 가까이서 인화할 때 필요한 증기를 발산하는 액체의 최저온도 또는 점화원 존재시 인화가 일어날 수 있는 최저온도, 그리고 가연성증기의 포화증기압이 공기와 혼합기체의 폭발한계 하한농도와 같게 되는 온도로 정의한다. 폭발한계는 발화원이 존재할 때 가연성가스와 공기가 혼합하여 일정 농도범위 내에서만 연소가 이루어지는 혼합범위를 말한다. 본 연구에서는 실제 공정에서 사용되고 있는 n-Hexadecane의 인화점을 측정하여 이를 기존 문헌값과 비교 하였고, 측정된 인화점을 이용하여 폭발한계를 예측하였다. 예측된 폭발한계를 여러 문헌에 제시된 자료과 비교하여 공정안전에 타당한 자료를 제시하였다. 본 연구는 n-Hexadecane을 취급하는 공정에서 안전 확보의 중요한 지침 마련과 MSDS D/B의 최신화에 유용한 정보를 제공하는데 목적이 있다.

• Journal of Welding and Joining
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• v.14 no.5
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• pp.49-58
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• 1996

In Korea Gas Corporation, as one of the pipeline repairing methods, damaged pipelines are sometimes treated with a temporally employment of split sleeve. On conducting the repair process, circumferential fillet and longitudinal groove welding usually must be included. For the case of groove welding, a considerable amount of R&D have been carried out related to property changes, while few study on the property change in fillet welding has been conducted. In this paper, so as to confirm the specification of fillet welding in terms of safety and reliability, properties changed by fillet welding were investigated for two welding processes. Qualifying tests such as reviewing macrostructure and nick-break tests were performed according to API 1104 and ASME section IX. In addition, tensile properties and hardness were evaluated according to KS B0841 and BS 4515. The fillet weld prepared by the qualified procedure showed melting depth of 0.8∼1.3mm and heat affected zone of 2.8∼3.4mm length. No crack and lack of penetration were observed. And the results of hardness and nick-break tests satisfied code requirements. The area crossed by fillet and groove welding line was found to have minimal tensile strength.

• Journal of Biosystems Engineering
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• v.29 no.5 s.106
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• pp.451-456
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• 2004

To establish a Altari radish pre-processing system far kimchi, the leaves and root tail of the Altari radish cutting de-vices were developed. The cutting resistances depend on the edge angles, oblique angles and cutting speeds were measured and analyzed. The experiments were performed to reveal the optimal conditions that showed the minimum cutting resistances acting on the materials. As the results, the optimum conditions that acting on the leaves were at edge angle $25^{\circ}$, oblique angle $40^{\circ}$ and cutting speed 0.5 m/s, and those acting on the root tails were at edge angle $20^{\circ}$, oblique angle $30^{\circ}$ and cutting speed 0.5 m/s, respectively. Considered a safety conception, the oblique angle of the leaves cutting device was adjusted as $20^{\circ}$, and then the cutting efficiencies of the both devices at these conditions were showed perfect performances.

• 대한임상약리학회:학술대회논문집
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• 2001.12a
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• pp.24-25
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• 2001

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1879-1882
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• 2005

Due to increase of demands on safety and convenience for automotive vehicle, the use of DC motor, such as power window, seat adjusting, pedal adjusting, sunroof, electric shift motor and so on, is increasing rapidly in the whole world. Worm gear is an important part to transmit torque to another gear in gear mechanism of automotive DC motor. But with current forming process, it has some problems in manufacturing and the quality. Also, the characteristics of automotive parts such as price and mass-production limit the quality improvement. Recently several methods are used in order to reduce a worm screw machining time and to maintain precision. In this paper, we introduce whirling tool machining and side milling cutter machining as effective manufacturing method of worm screw and study on the cutting force of side milling cutter and whirling tool in worm screw machining.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.881-885
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• 2002

This paper presents the performance and the algorithm of a 1/3-octave band spectrum control system. The system is developed to provide various spectrums in a high intensity acoustic chamber. The required spectrum, which usually comes from launch vehicle company, starts from 25Hz band and ends 10kHz band. Automatic spectrum control system is preferred since the system requires short settling time to guarantee the safety of test objects and to reduce the amount of operating gas. The developed system adapted a PCI data-acquisition/signal-generation board installed in a personal computer to implement whole control logic. The control software used three cascade digital Butterworth filters using software. The filers are designed following ANSI S1.11 standard to implement 1/3 octave band filter bank. The graphical user interface of the system guides the user to follow standard operation procedure. The averaged control spectrum showed less than 0.05 dB in every running 1/3-octave band.

• Magazine of the Korean Society of Agricultural Engineers
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• v.15 no.3
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• pp.3096-3106
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• 1973

As a link in the chain of antidrought measure, our attempt is made to obtain basic informations on the construction of an infiltration gallary which can be supplied with irrigation water by catching of underground water in small river beds, which is economical, permanent and efficient. The experiment was made, concerning the structure of catchment conduits, by constructing a model sand tank $1.5m{\times}5m{\times}1.5m$ in dimension made of reinforced concrete. Various kinds of measuring equipment were attached to the model tank which contains a set of catchment conduits, each of them was made 30cm in diameter and 60cm in length with the ratio of sectional area to total area of influx holes 10:1, 20:1, 30:1. The average size of influx holes was fixed from 0mm to 10mm, 20mm and 30mm in diameter respectively. Obtained results are as follow; (a) In view of the water catchment capacity, manufacturing cost and the antipressure strength of the catchment conduits, it is the best method to decide the total number of influx holes 20 per sq. meter of each tile surface, and the size of influx holes 20mm in diameter, when the conduits have diameter less than 1m. (b) The greatest factor of safety against external load is to arrange the influx holes in a zigzag manner on the tile surface. The most effective formula of arrangement is $S{\geqq}\sqrt{2gd}$ where: s : spacing of opening row. g : spacing of opening line. d : diameter of influs hole.

• Structural Engineering and Mechanics
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• v.61 no.6
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• pp.711-719
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• 2017

This study investigates the effects of reinforcing bar diameter and cover depth on the shrinkage behavior of restrained ultra-high-performance fiber-reinforced concrete (UHPFRC) slabs. For this, twelve large-sized UHPFRC slabs with three different rebar diameters ($d_b=9.5$, 15.9, and 22.2 mm) and four different cover depths (h=5, 10, 20, and 30 mm) were fabricated. In addition, a large-sized UHPFRC slab without steel rebar was fabricated for evaluating degree of restraint. Test results revealed that the uses of steel rebar with a large diameter, leading to a larger reinforcement ratio, and a low cover depth are unfavorable regarding the restrained shrinkage performance of UHPFRC slabs, since a larger rebar diameter and a lower cover depth result in a higher degree of restraint. The shrinkage strain near the exposed surface was high because of water evaporation. However, below a depth of 18 mm, the shrinkage strain was seldom influenced by the cover depth; this was because of the very dense microstructure of UHPFRC. Finally, owing to their superior tensile strength, all UHPFRC slabs with steel rebars tested in this study showed no shrinkage cracks until 30 days.