• 한국축산식품학회지
• /
• 제37권2호
• /
• pp.254-263
• /
• 2017

The inhibition effect of persimmon peel extracts (PPE) (0.05(PPE-0.05), 0.1(PPE-0.1), and 0.2 g(PPE-0.2) per meat sample) on lipid and protein oxidation of pork patties during chilled storage for 12 days were investigated and compared to ascorbic acid (As-0.05) and butylhydroxytoluene (BHT) (BHT-0.01). The meat samples treated with PPE had greater (p<0.05) $a^*$ values comparing control in raw pork patties meat from day 4 of storage. The addition of PPE at all concentrations on meat samples effectively inhibited the formation of oxidation products as shown by decreasing conjugated dienes (CD), peroxide values (POVs), thiobarbituric acid reaction substances (TBARS), and carbonyl content during chilled storage for 12 d. The PPE-0.2 and BHT-0.01 had the lowest in decrease rate of free thiol content (0.24 and 0.22 times) during chilled storage. Therefore, results of this study suggest that PPE can be considered a potential antioxidant against lipid and protein oxidation of raw meat products.

• 설비공학논문집
• /
• 제12권4호
• /
• pp.354-362
• /
• 2000

Optimal supervisory control strategy for the set points of controlled variables in the central cooling system has been studied by computer simulation. A quadratic linear regression equation for predicting the total cooling system power in terms of the controlled and uncontrolled variables was developed using simulated data collected under different values of controlled and uncontrolled variables. The optimal set temperatures such as supply air temperature, chilled water temperature, and condenser water temperature, are determined such that energy consumption is minimized as uncontrolled variables, load, ambient wet bulb temperature, and sensible heat ratio, are changed. The chilled water loop pump and cooling tower fan speeds are controlled by the PID controller such that the supply air and condenser water set temperatures reach the set points designated by the optimal supervisory controller. The influences of the controlled variables on the total system and component power consumption was determined. It is possible to minimize total energy consumption by selecting the optimal set temperatures through the trade-off among the component powers. The total system power is minimized at lower supply, higher chilled water, and lower condenser water set temperature conditions.

• 설비공학논문집
• /
• 제6권3호
• /
• pp.175-181
• /
• 1994

This paper deals with the correlation of absorption rate in absorber and evaporation rate in evaporator. The evaporator consists of a copper tube of 10mm dia, and 600mm long and chilled water flowing through the tube is fed by the chilled water circulator. The flowrate of LiBr-water solution in the absorber plays a significant role in determining the magnitude of the heat transfer rate from chilled water to refrigerant There exists a flowrate of solution which has a maximum value of heat transfer. It is interesting to note that the absorption rate of absorber increases with increasing the heat transfer rate of the evaporator. Also, absorption rate increases with evaportation rate, and the ratio(the former/the other) depends on the inlet temperature of LiBr-water solution in the absorber. The heating capacity in the absorber is higher than the refrigerating capacity in the evaporator.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2008년도 하계학술발표대회 논문집
• /
• pp.1099-1104
• /
• 2008

Recent year, mean energy consumptions of a people are higher than other country. And international oil price became over 120 dollar. This energy environment as well as energy war. Maybe, the Meteorological Administration is going to enforce scorching heatwave special report system from that come summer. Besides, 2008 summer, maximum demand power is expected by 64,240,000kW. The electric power equipment reserve rate appeared in to keep 12.5% level. Chilled water storage system witch is one of electric load administration system. Heat pump system used cooling tower heat recovery is advantage that use is possible to summer in small a public bath building. In this paper, we suggest that heat pump system by heat recovery using cooling tower when it is heating operation of ambient air temperature. To apply cooling tower heat recovery heat pump to chilled water heat storage type and achieved performance evaluation about operation. As a result, performance of heat pump system that about 121% in cooling mode, 138% in heating mode higher than KEPCO standard. And heating operation possible to ambient air temperature about $23^{\circ}C$, which of appear cooling tower outlet temperature about $13^{\circ}C$.

• 한국주조공학회지
• /
• 제26권4호
• /
• pp.180-183
• /
• 2006

NICI재의 미세조직 및 기계적 성질에 미치는 Ni 첨가원소의 영향을 연구하였다. 선재공장의 열간압연롤재로서의 NICI재는 내열 피로크랙성, 경도값, 인장성질, 내마모성이 매우 중요하다. 주방상태에서 4% Ni 첨가로 주요 기지상인 퍼얼라이트상이 베이나이트상으로 변화되었다. 베이나이트상을 주요 기지상으로 가지는 4% Ni 첨가 NICl재는 퍼얼라이트상을 주요 기지상으로 가지는 통상의 NICI재에 비해서 경도값(HRC 48) 및 인장강도값($72\;kg/mm^2$)이 우수하였으며, 이는 선재압연롤 재료로서 우수한 성능을 발휘할 수 있을 것으로 예측된다.

• 설비공학논문집
• /
• 제20권7호
• /
• pp.508-516
• /
• 2008

Fault detection and diagnosis(FDD) system is beneficial in equipment management by providing the operator with tools which can help find out a failure of the system. An experimental study has been performed on fault detection and diagnosis method for a water chiller. Bayes classifier, which is one of classical pattern classifiers, is adopted in deciding whether fault occurred or not. Failure modes in this study include refrigerant leakage, decrease in mass flow rate of the chilled water and cooling water, and sensor error of the cooling water inlet temperature. It is possible to detect and diagnose faults in this study by adopting FDD algorithm using only four parameters(compressor outlet temperature, chilled water inlet temperature, cooling water outlet temperature and compressor power consumption). Refrigerant leakage failure is detected at 20% of refrigerant leakage. When mass flow rate of the chilled and cooling water decrease more than 8% or 12%, FDD algorithm can detect the faults. The deviation of temperature sensor over $0.6^{\circ}C$ can be detected as fault.

• 설비공학논문집
• /
• 제18권10호
• /
• pp.776-782
• /
• 2006

A new district cooling system using ice slurry for the uncertain cooling load of the future is presented. The chilled water produced by the absorption chillers is used for the base cooling load. The temperature of the chilled water is reduced by mixing of ice slurry depending on increasing of the cooling load. Finally, IF of the ice slurry is increased up to 10% at the peak load. The transporting mass flow rate is decreased down to 44.7%, and the diameter of the main pipe is decreased down to 66.7%, but the diameter of the branched pipe is designed as the same size of the chilled water.

• Fisheries and Aquatic Sciences
• /
• 제25권2호
• /
• pp.64-75
• /
• 2022

This study aimed to investigate the effect of different coating materials on the quality of shrimp (Litopenaeus vannamei) during chilled storage for 10 days. Fresh shrimp were randomly divided into five groups: the control group, the hypotaurine treatment group (2%), the chitosan group (1%), the hypotaurine + chitosan group (2% hypotaurine solution with 1% of chitosan), and the sodium metabisulfite treatment group (1.25%). Compared with other treatments, the lower accumulation of total visible counts (TVC, 5.25 Log₁₀ CFU/g), total volatile basic nitrogen (TVB-N, 22.5 mg/100 g) and thiobarbituric acid values (TBA, 0.58 mg MDA/kg) suggested that coating of chitosan-hypotaurine could retard the microbial activity, protein degradation and lipid oxidation of shrimp. Meanwhile, results demonstrated that the chitosan coating combined with hypotaurine showed an excellent performance in inhibiting quality deterioration (pH 7.5, ∆E 7.0, hardness 393 g, and elasticity 0.69). Furthermore, the melanosis degree of shrimp was alleviated, and the sensory parameters, including appearance, odor and texture, were maintained to the acceptable level by chitosan based hypotaurine treatment during the chilled storage.

• 한국축산식품학회지
• /
• 제22권3호
• /
• pp.222-227
• /
• 2002

진공포장한 한우육 우둔부위를 1$^{\circ}C$, 4$^{\circ}C$의 일반공기순환 냉장고와 1$^{\circ}C$, 4$^{\circ}C$의 냉수에 침지하여 3, 7, 10, 14일 동안 저장하였을 때, 처리구간의 물리적 육색 (CIE L*, a*, b*)은 크게 변화하지 않은 것으로 나타났다. 그러나 육색소 산화를 나타내는 MetMb의 함량은 처리구간에 따라 변화를 보여 대조구 (4$^{\circ}C$-공기순화)가 가장 빠른 증가를 나타내었으며, 저장 14일째 T2 (4$^{\circ}C$-냉수침지)구가 유의적으로 (p<0.05) 낮은 MetMb함량을 보였다. 한편 이런 결과는 지방산화와도 유사한 경향을 보였는데, 대조구 (4$^{\circ}C$-공기순환)의 TBARS 수치가 저장기간 동안 가장 빠른 증가를 나타낸 반면, T3(1$^{\circ}C$-냉수침지) 구의 TBARS는 크게 증가하지 않았다. 이러한 결과는 냉수침지 방법이 지방산화와 육색소 산화를 억제시킬 수 있다는 것을 의미한다. 포장감량 또는 공기순환 처리구(control, T1)가 냉수침지 처리구(T2, T3)에 비해 높게 나타났다. 총 육색소 함량은 전 저장기간 동안 처리구간에 유의적(p>0.05)인 차이가 없었다. 이상의 결과를 종합해 볼 때, 한우육을 진공포장하여 1$^{\circ}C$ 냉수에 침지시켜 숙성시키는 방법이 지방산화를 억제시키고 육색소의 안전성을 유지할 뿐만 아니라 포장감량도 줄일 수 있는 숙성법이라고 사료된다.

• 한국축산식품학회지
• /
• 제22권3호
• /
• pp.228-233
• /
• 2002

본 연구는 진공포장 한우육의 냉수침지 숙성방법이 한우육의 연도 및 미생물증식에 미치는 영향을 구명하고자 수행하였다. 저장기간이 경과함에 따라 근절길이는 냉수침지 처리구가 저장 3일째 유의적(p<0.05)으로 긴 것으로 나타났으며, 저 장 3일째를 제외 한 저 장기간 동안 유의적 인 차이는 없었으나 대조구에 비해 긴 경향을 보였다. 또한 유리칼슘 농도에 있어서도 저장 7일 째 냉수침지 처리구가 유의적(p<0.05)으로 높게 나타났으며, 역시 저장 7일째를 제외한 저장기간 동안 유의적인 차이는 없었으나 대조구에 비해 높은 경향을 보였다. 한편 전단가와 근원섬유 소편화 지수에 있어서는 저장기간이 경과함에 따라 두 처리구간에 있어서 유의적인 차이는 나타나지 않았지만, 냉수침지 처리구가 상대적으로 낮은 전단가와 높은 소편화지수의 경향을 보였다. 이 같은 결과는 냉수침지 숙성이 일반공기순환냉장고의 숙성보다 근절의 길이를 길게 하고, 근형질내 칼슘의 농도를 높이며, 소편화 지수를 높게 한 결과 연도를 향상시킬 수 있다는 가능성을 제시한 것으로 사료된다. 덧붙여, 총세균수는 일반공 기순환냉장실에 저장한 것에 비해 냉수침지 처리구가 유의적(p<0.05)으로 낮은 것으로 나타나, 온도의 변이를 줄이는 것에 기인하여 미생물의 성장억제에도 효과적일 것으로 사료된다.