• 설비공학논문집
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• 제18권10호
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• pp.761-767
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• 2006

In this study, performance of 2 pure hydrocarbons R290 and R1270 was measured in an attempt to substitute R22 under 3 different temperature conditions. They were tested in a refrigerating bench tester with a hermetic rotary compressor. The test bench provided about 3.5 kW capacity and water and water/glycol mixture were employed as the secondary heat transfer fluids. All tests were conducted under the same external conditions resulting in the average saturation temperatures of $7/45^{\circ}C$ and $-7/41^{\circ}C$ and $-21/28^{\circ}C$ in the evaporator and condenser, respectively. Test results show that the coefficient of performance (COP) of these refrigerants is up to 11.54% higher than that of R22 in all temperature conditions. Compressor discharge temperatures were reduced by $14{\sim}31^{\circ}C$ with these fluids. There was no problem with mineral oil since the mixtures were mainly composed of hydrocarbons. The amount of charge was reduced up to 58% as compared to R22. Overall, these fluids provide good performance with reasonable energy savings without any environmental problem and thus can be used as long term alternatives for residential air-conditioning and heat pumping application.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.58-63
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• 2006

In this study, performance of 2 pure hydrocarbons and 3 mixtures was measured in an attempt to substitute R22 under 3 different temperature conditions. The mixtures were composed of R1270(propylene), R290(propane) and R152a. They were tested in a refrigerating bench tester with a hermetic rotary compressor The test bench provided about 3.5 kW capacity and water and water/glycol mixture were employed as the secondary heat transfer fluids. All tests were conducted under the same external conditions resulting in the average saturation temperatures of $7^{\circ}C/45^{\circ}C$ and $-7^{\circ}C/41^{\circ}C$ and $-21^{\circ}C/28^{\circ}C$ in the evaporator and condenser, respectively. Test results show that the coefficient of performance (COP) of these refrigerants is up to 11.54% higher than that of R22 in all temperature conditions. Compressor discharge temperatures were reduced by $14{\sim}31^{\circ}C$ with these fluids. There was no problem with mineral oil since the mixtures were mainly composed of hydrocarbons. The amount of charge was reduced up to 58% as compared to R22. Overall, these fluids provide good performance with reasonable energy savings without any environmental problem and thus can be used as long term alternatives for residential air-conditioning and heat pumping application.

• 설비공학논문집
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• 제18권4호
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• pp.312-319
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• 2006

In this study, performance of 2 pure hydrocarbons and 7 mixtures was measured in an attempt to substitute HCFC22 used in air-conditioners and heat pumps. The mixtures were composed of R1270 (propylene), R290 (propane), HFC152a, and RE170 (Dimethyl ether, DME). The pure and mixed refrigerants tested have GWPs of $3{\sim}58$ as compared to that of $CO_2$ and the mixtures are all near-azeotropic showing the gliding temperature difference (GTD) of less than $0.6^{\circ}C$. Thermodynamic cycle analysis was carried out to determine the optimum compositions and actual tests were performed in a laboratory heat pump test bench at the evaporation and condensation temperatures of 7.5 and $45.1^{\circ}C$ respectively. Test results show that the coefficient of performance (COP) of these mixtures is up to 5.7% higher than that of HCFC22. While propane showed 11.5% reduction in capacity, most of the fluids tested had the similar capacity to that of HCFC22. Compressor discharge temperatures were reduced by $11{\sim}17^{\circ}C$ with these fluids. There was no problem with mineral oil since the mixtures were mainly composed of hydrocarbons. The amount of charge was reduced up to 55% as compared to HCFC22. Overall, these fluids provide good performance with reasonable energy savings without any environmental problem and thus can be used as long term alternatives for. residential air-conditioning and heat pumping application.

• 수산해양교육연구
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• 제23권4호
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• pp.709-722
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• 2011

This study was investigated to obtain basic data which can be applied to processing of retort pouched seasoned sea mussel. Shell was washed and steamed before shucking. Sea mussel meat was seasoned in boiled and mixed seasoning sauce(soy sauce 23%, monosodiun glutamate 2%, sorbitol 2%, sesame oil 1%, vinegar 2%, starch syrup 15%, water 55%) for 30 min. The seasoned sea mussel was vacuum packed in plastic film bag and sterilized for various Fo values(Fo 7~13 min.) in a hot water circulation system retort at $121^{\circ}C$. The chemical composition such as pH, VBN, amino-N, total amino acid, free amino acid, color value (L, a, b), texture profile, TBA value, mineral, sensory evaluation and viable cells count of the retort pouched seasoned sea mussels sterilized with various conditions(Fo 7~13 min.) were measured. The same experimental items were also measured during storage. There was no remarkable difference between sterilization conditions and sensual characteristics. The results showed that the product sterilized at Fo 7 min. was the most desirable because this condition is most economical.

• 수산해양교육연구
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• 제23권4호
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• pp.662-672
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• 2011

This study was investigated to obtain basic data which can be applied to processing of canned seasoned kwamaegi. Commercial Kwamaegi was cut into $2{\times}3cm$ lengths, filled 90 g into can (301-3) and added with 60 g water before precooking for 10 min. at $100^{\circ}C$. The precooked Kwamaegi was packed into the can, and added with 60 g seasoning sauces, which was prepared by mixing soy sauce 23%, monosodium glutamate (MSG) 2%, sorbitol 2%, sesame oil 1%, vinegar 2%, starch syrup 17%, sake 5%, water 48%. The cans were sealed using a vacuum seamer and then sterilized for various Fo values (Fo 8~12 min.) in a steam system retort at $121^{\circ}C$. The factors such as pH, VBN, amino-N, total amino acid, free amino acid, color value (L, a, b), texture profile, TBA value, mineral, sensory evaluation and viable bacterial count of the canned seasoned Kwamaegi produced with various sterilization condition(Fo 8~12 min.) were measured. There was no remarkable difference between sterilization conditions and sensual characteristics. The results showed that the product sterilized at Fo 8 min. was the most desirable because this condition is most economical.

• 한국수산과학회지
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• 제54권4호
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• pp.532-542
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• 2021

The concern of senior-friendly foods has been increasing as the population of older in world grows at a rapid pace. This study was conducted to investigate general and nutrition characterization of domestic commercial senior-friendly foods (DC-SFF). The protein content of DC-SFF ranged from 1.1-14.6 g/100 g, which was 1.8-24.3% for male elderly people and 2.2-29.2% for female elderly people based on the daily recommended intake of protein. Total amino acid content of DC-SFF ranged from 1,038-14,539 mg/100 g. Salinity of DC-SFF ranged from not detected-1.9 g/100 g, which was 0.0-49.9% for elderly people based on the daily recommended intake of salinity. Mineral content of DC-SFF ranged from 11.0-414.4 mg/100 g calcium, 14.6-226.5 mg/100 g potassium, 1.9-30.4 mg/100 g magnesium and not detected-4.8 mg/100 g zinc. The fatty acid composition was mainly affected by main material and added oil.

• 터널과지하공간
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• 제29권1호
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• pp.12-29
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• 2019

최근의 이산화탄소 심지층 처분, 인공지열저류층 형성 및 발전, 원유회수증진 사업 등에는 고압의 유체를 주입하는 과정이 수반되고 이들 사업의 안전하고 성공적인 수행을 위해서는 대상 부지 절리 암반의 투수 특성 및 주입압에 의한 역학적 변형에 기인한 변화를 정확하게 평가하는 것이 중요하다. 본 고에서는 절리 암반 수리-역학 특성 파악을 위한 해석적 및 실험적 평가 방법에 대해 검토하였다. 먼저 유체 주입 전 절리 암반 초기 투과 특성 및 수리-역학 특성 평가에 고려해야 할 기술요소를 분석하고 현장 시추공 실험을 통해 이들 수리-역학 특성을 직접 측정하기 위한 최근의 SIMFIP 실험장치의 특징 및 활용방안에 대해서도 검토하였다.

• 공업화학
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• 제22권1호
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• pp.114-118
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• 2011

미네랄 오일을 결합재로 사용하는 탄소반죽전극은 효소의 특성 연구 분야에서 효과적으로 활용되고 있으나 전극이 기계적 경도가 없으므로 실용화의 가능성은 없다. 본 실험실에서는 톨루엔에 녹인 고무 용액이 탄소가루의 결합재로 사용될 때 탄소반죽의 기계적 물성이 얻어지는 것을 확인하였다. 클로로프렌 고무 용액을 이용하여 만든 전극이 정량적인 전기화학적 행동을 보이는지 확인하기 위하여 여러 가지 속도론적 파라메터 즉 대칭인자($\alpha$, 0.28), 교환전류밀도 ($i_0$, $4.06{\mu}A/cm^2$), 이중층의 축전용량($C_d$, $2.11{\times}10^{-3}F$), Michaelis 상수($K_M$, $2.45{\times}10^{-3}M$), 시간상수(${\tau}_B$, 0.077 sec) 등을 구하였다. 이 실험적 사실들은 클로로프렌 고무가 탄소반죽전극의 실용화에 전망 좋은 결합재임을 입증하였다.

• 지질공학
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• 제31권4호
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• pp.549-559
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• 2021

북극권은 막대한 양의 화석연료와 광물자원이 매장되어 있어 개발과 건설 사업이 활발히 추진되고 있다. 전 지구적으로 기후변화에 적극적으로 대응하기 위해 노력하고 있으나, 여전히 천연자원의 의존도는 매우 높다. 본 논문에서는 북극권 국가 중 비전통(오일샌드) 에너지·자원개발이 활발히 진행 중인 캐나다(앨버타주)를 대상으로 조사연구를 수행하였다. 광범위한 지역에 대한 조사비용과 시간을 절감하기 위하여 위성영상을 활용하여 토지피복도를 작성하였다. 토지피복도의 픽셀을 계산하는 방식으로 캐나다(앨버타주) 오일샌드 개발 활동이 활발히 진행되고 있는 지역의 계절별 건설환경(지표 온도 변화, 적설분포 면적 등) 자료를 구축하였다. 본 논문에서 수행한 조사·분석 방법론은 북극권 자원 개발 사업의 성공적 추진과 운영을 위한 전략수립, 기본 설계 등에 활용될 것으로 기대한다.

• 한국안전학회지
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• 제39권1호
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• pp.9-15
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• 2024

Hydrogen-based electricity and transportation systems are widely recognized as sustainable power sources. However, the low ignition energy of hydrogen, only 1/10th that of conventional fossil fuels, poses a safety concern involving the risk of ignition due to electrostatic discharge from facility workers. Therefore, anti-static systems are imperative for hydrogen-based electricity facilities. To address this, we propose a reliable conductive rubber mat (CRM) to ensure the safety of these facilities. Unlike conventional anti-static floors that utilize conductive paint (CP), the CRM features a uniform distribution of conductive components in chemically and mechanically stable rubber. As a result, the CRM is unyielding to polar solvents (such as ethanol and hydrosulfuric acid) and non-polar solvents (like mineral oil) without increasing its resistance. Moreover, the CRM can withstand mechanical stress. Consequently, the human-body voltage of workers on the CRM would be sufficiently low enough to protect them from hydrogen explosions, thereby enhancing overall safety.