• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.4
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• pp.475-482
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• 2016

The active control of noise generated by the compressor and transmitted out of the machine room through the windows is implemented based on the FIR filter. The machine room contains most of noise sources of electric home appliances, air-conditioners and refrigerators, for example. To actively reduce the noise from the machinery room. In this paper, the transfer function of the controller for minimization of the acoustic power transmitted through the windows is mathematically formulated. The transfer functions required for implementation of the active controller are the measured. The measurements are conducted in this initial stage under the operation of the compressor with no load. For improvement of the reliability of the transfer function of the compressor to the acoustic power, additional operational measurements are performed. The real time controller is implemented based on the FIR filter using the measured transfer functions and the performance of the active controller is estimated. Control performance is measured about 3 dB ~ 10 dB in reduction of the sound power at the peaks of the compressor noise.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2009.04a
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• pp.379-384
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• 2009

본 연구에서는 다세대 주택에서 발생되는 화재에서 가연물질이 되는 가구류에 대한 화재 특성을 파악하기 위해 단위 가연물에 대한 열방출율(HRR, Heat Release Rate), 연기발생량, 유독가스 발생량 등에 대한 기본 DB를 확보하고자 하였다. 실험에 사용된 단위가연 물에는 침대(매트리스 포함), 장롱, 화장대, 책상, 책장, 소파(3+1인용), TV, 싱크대(찬장포함), 냉장고, 이불(옷가지)등 총 12여종이며, 국제 시험 규격인 ISO 9705 시험법인 중규모 시험 장치(Room Corner Tester)와 10MW 급의 실규모화재실험장치(Large Scale Calorimeter)에서 실험을 진행하였다. 실험결과 냉장고에서 가장 높은 최대 열방출율 약 3051 kW, 장롱에서의 일산화탄소 방출량은 최대 약 3894.2 ppm, 이산화탄소의 방출량은 최대 약 1.8% 로 가장 높게 측정되었다. 이러한 중규모 시험 장치를 통한 단위 품목의 화재특성 DB 작성은 단위구획에서의 화재 확산 예측에 가장 중요한 요소가 될 수 있을 것이다.

• Journal of Power System Engineering
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• v.7 no.2
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• pp.17-22
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• 2003

As side-by-side refrigerators came into existence, there has been a growing concern about the free%ins-up of the vital equipment in a walk-in freezer. Due to a bad performance, customers are experiencing too much frustration. In order to minimize the freezing phenomena, the numerical simulation has been performed on the characteristics of cold air flow in a side-by-side refrigerator. The flow field has been simulated with a standard $k-\varepsilon$ turbulent model and a SIMPLE algorithm based on the finite volume method. Through the results of the analysis of the pattern of cold air flow, finally the shape of outlet for cold air flow was modified. The present model was compared with the modified model. The latter was better than the former in minimizing the freezing phenomena.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2002.05a
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• pp.101-106
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• 2002

In the Refrigeration and air conditioning industrial circles, refrigerator is demands a high degree of efficiency due to the Environmental Preservation Law. Many researchers are working on factors to improve the efficiency of the refrigerator In this paper, a study of the factors on the decrease of electric power consumption, several experiments are performed to improve the fluid flow in the refrigerator machine room. As a results, average temperatures of compressor and condenser are reduced 3.1$^{\circ}C$, 2.$0^{\circ}C$. The consuming electric power rate is reduced 0.7kWh/month.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.10a
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• pp.427-428
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• 2009

In the manufacture process of refrigerator cabinet, polyurethane(PU) liquid firstly is injected between outer plate and inner case in high temperature about $40^{\circ}C$, and PU foam is generated and solidified to the room temperature. There will be great residual stress in the PU foam, especially at the corners after the whole refrigerator is completely assembled. The stress condition will become more complicated under operating condition because of the large temperature difference between the freezing room and outer plate. And also, there are great differences of properties for plastic and steel which would cause different deformation under temperature gradient. The steel outer plate would expand compared to the PU foam or ABS material under operation condition, which induces a thermally bowing deformation in the refrigerator cabinet. The objective of this paper is to design an optimum bead structure or to use reinforcement in the refrigerator except for improving material properties in order to decrease the deformation.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.530-533
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• 2008

Refrigerators have some frost related problems in a freezing compartment. The frost formation in the refrigerator gives customers a bad impression concerning quality problems. Therefore, many engineers have been studying the optimum solution to avoid frost formation. But the problem of frost formation is very complex and hard to approach to the answer. The frost generation of a household refrigerator have been widely known that is closely related to the distribution of temperature inside the compartment. The distribution depends on the cold air circulation inside the refrigerator. So frost problem can be reduced and energy consumption efficiency also improved through optimization of air flow fields inside the freezing compartment. In this paper, numerical simulation has been carried out to check fluid flow. The variation of temperature at the walls was measured and quantitative analysis of frost generated from the freezing compartment was carried out. Through comparison between simulation and experiment, some correlation revealed.

• Proceedings of the SAREK Conference
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• 2003.07a
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• pp.219-219
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• 2003

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2003.06a
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• pp.95-117
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• 2003

본 연구는 한우육의 육질등급과 저장기간에 따른 육질 및 저장특성과 맛성분의 차이를 조사하고자 실시하였으며, 도축 24시간 후 도체등급판정을 실시한 한우 36두의 등심부위를 시료로 취하여 $2^{\circ}C$ 냉장실에서 14일간 저장하면서 이화학적 특성 및 관능적 특성을 조사하였다. 그 결과를 요약하면 다음과 같다. 육질등급에 따른 도체 특성에 있어서 등급간의 지방두께, 배최장근 단면적 및 육량등급은 차이가 없었으며, 육색과 지방색, 성숙도 등도 차이가 없는 것으로 나타났으나 조직감은 1등급육이 3등급육에 비하여 좋은 것으로 나타났다. 1등급육은 3등급육에 비하여 지방함량(9.87${\pm}$2.23%)이 높았으며, 수분함량(67.75${\pm}$l.63%)이 낮았으나(p<0.05), 단백질함량은 육질등급간에 차이가 없었다. 도축 24시간후의 L, b, h-값은 등급간에 차이가 없었으며, a와 C-값은 2등급육이 다른 등급에 비하여 다소 높게 나타났다. L, a, b-값 모두 저장기간이 경과함에 따라 다소 증가하였다. pH는 육질등급간에 차이가 없었으며 저장기간에 따른 차이도 없었다. 1등급육은 3등급육에 비하여 드립감량은 다소 낮은 것으로 나타났으며, 가열감량은 등급간에 유의적인 차이는 없었으나 1등급육이 가장 적은 가열감량을 나타냈다. 보수력은 1등급육이 2, 3등급육에 비하여 유의적으로 높았으며, 근절길이와 콜라겐 함량은 등급간에 차이가 없었다. 전단력값은 3등급육이 1, 2등급육에 비하여 다소 높은 전단력값을 보였으나 유의적인 차이는 없으며, 근원섬유 소편화도는 등급간에 차이가 없었다. 저장기간이 경과합에 따라 전단력값은 점차적으로 낮아졌고 근원섬유 소편화도는 유의적으로 증가하였다. 1등급육이 2, 3등급육에 비하여 TBA가가 높았고, VBN함량은 낮았으나 유의적인 차이는 없었으며, 저장기간이 경과함에 따라 TBA가와 VBN함량은 증가하였다. 관능평가에서 풍미는 육질 등급간에 차이가 없었으나, 연도, 다즙성 및 전체적인 기호도는 1등급육이 3등급육에 비하여 다소 우수한 것으로 나타났다.

• Korean Journal of Food Science and Technology
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• v.30 no.6
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• pp.1312-1320
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• 1998

Some commercial beef loins in raw state were packaged with PVDC as aerobic and vacuum condition. The other beef samples were cooked until core temperature arrived at $70^{\circ}C$ and then packaged immediately in the same way as the raw state. These samples were irradiated by electron beam (0, 1, 2 kGy), and then stored in refrigerator $(2{\sim}4^{\circ}C)$. Identity and quantity of cholesterol oxides were analysed at the 0, 7th, 14th day of storage. In the samples that were raw and packaged aerobically, $7{\alpha}-hydroxycholesterol,\;{\beta}-epoxide,\;7{\beta}-hydroxycholesterol$ and 7-ketocholesterol were detected over $0.5\;{\mu}g/g$. Cholestanetriol and${\alpha}-epoxide$ were detected at levels below $0.5\;{\mu}g/g$ during storage. In the samples that were raw and vacuum-packaged, $7{\alpha}-hydroxycholesterol$, 7-ketocholesterol and cholestanetriol were detected. In the samples that were cooked and packaged aerobically, cholestanetriol and ${\alpha}-epoxide$ were detected below $0.5\;{\mu}g/g$ during storage. $7{\alpha}-hydroxycholesterol,\;{\beta}-epoxide,\;7{\beta}-hydroxycholesterol$and 7-ketocholesterol were detected as $1.53{\sim}26.81,\;1.07{\sim}5.23,\;40.64{\sim}101.30\;and\;7.16{\sim}33.91\;{\mu}g/g$, respectively. In all results, total amounts of cholesterol oxide increased significantly as irradiation dose and storage time increased (P<0.05).

• Journal of Animal Science and Technology
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• v.45 no.5
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• pp.825-834
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• 2003

Chicken thigh from a retail market were used as experimental samples. Some chicken samples of raw state were packaged with PVDC at an aerobic and vacuum condition. The other samples were cooked until core temperature arrived at 70$^{\circ}C$ and then packaged immediately in the same way of raw samples. After samples were irradiated by electron beam at 6 kGy, they were stored in a refrigerator. Identification and quantity of cholesterol oxides were made at 0 and 7 days of storage, respectively. During the early stage of storage, 7$\beta$-hydroxycholesterol, $\alpha$,$\beta$-epoxide, cholestanetriol and 7-ketocholesterol were produced from the raw meat samples, and the production of these chemicals were significantly higher(P〈0.05) from the samples with aerobic packaging than those with vacuum packaging. With storage time, 7$\alpha$-hydroxycholesterol, 6-ketocholesterol and some other chemicals, which were not found during the early stage of storage, were found. Also, the formation of these chemicals were significantly increased(P〈0.05) with storage time. Cholesterol and lipid oxidation products of cooked meat after irradiation and irradiated meat after cooking were significantly increased(P〈0.05) with storage time for all treatments, and vacuum packaging results in showed significantly lower value(P〈0.05) than aerobic packaging. Summarizing the aforementioned results, it was found that the formation of cholesterol and lipid oxides and lipid oxidation was more easily affected by packaging condition than irradiation.