• Title/Summary/Keyword: high temperature storage

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REDUCTION CHARACTERISTICS OF NOx STORAGE CATALYST FOR LEAN-BURN NATURAL GAS VEHICLES

  • Lee, C.H.;Choi, B.C.
    • International Journal of Automotive Technology
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    • v.8 no.6
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    • pp.667-674
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    • 2007
  • Various types of NOx storage catalysts for NGV's were designed, manufactured, and tested in this work on a model gas test bench. As in most of other studies on NOx storage catalyst, alkaline earth metal barium(Ba) was used as the NOx adsorbing substance. The barium-based experimental catalysts were designed to contain different amounts of Ba and precious metals at various ratios. Reaction tests were performed to investigate the NOx storage capacity and the NOx conversion efficiency of the experimental catalysts. From the results, it was found that when Ba loading of a catalyst was increased, the quantity of NOx stored in the catalyst increased in the high temperature range over 350. With more Ba deposition, the NOx conversion efficiency as well as its peak value increased in the high temperature range, but decreased in the low temperature range. The best of de-NOx catalyst tested in this study was catalyst B, which was loaded with 42.8 g/L of Ba in addition to Pt, Pd and Rh in the ratio of 7:7:1. In the low temperature range under $450^{\circ}C$, the NOx conversion efficiencies of the catalysts were lower when $CH_4$, instead of either $C_3H_6$ or $C_3H_8$, was used as the reductant.

EFFECTS OF TEMPERATURE AND DURATION OF POST-IRRADIATION STORAGE ON SEEDLING HEIGHT OF WHEAT (감마선과 속중성자를 조사한 밀종자의 저장기간과 저장온도가 발아후 유묘생장에 미치는 영향)

  • Chang-Yawl Harn;Chi-Moon Kim;Young-Sang Kim
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.10
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    • pp.73-77
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    • 1971
  • The experiment was carried out to investigate post-irradiation storage effect which was related to temperature(i.e. at 2$^{\circ}C$, 17$^{\circ}C$ and 4$0^{\circ}C$) on wheat seeds; Weibull's Svenno, treated with gamma-ray and fast neutron. Results obtained showed that the seedling height in both radiation sources was decreased with prolongation of storage period, especially when the seeds were treated with high dosage and stored at high temperature(4$0^{\circ}C$). The results of this trial, however, showed that storage effect was influenced by irradiation dose, temperature and storage time.

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Normal Flora and Effect of Storage Temperature and Period in the Commercial Fish and Shellfish (시판 어패류의 정상세균군과 저장온도 및 저장기간이 정산세균군 변화에 미치는 영양)

  • 박석기;이용욱;정지연;김성원
    • Journal of Food Hygiene and Safety
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    • v.12 no.1
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    • pp.20-25
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    • 1997
  • In order to investigate bacterial sanitary condition of fish and shellfish, we examined the normal flora in the 25 species of commercial fish and shellfish, and also proportional change of normal flora by storage period and temperature. Isolated 334 wereisolated in the normal fish and shellfish and predominant genera were Pseudomonas (25.2%), Staphylococcus(10%), Acinetobacter (7.2%), Vibrio (6.9%), Micrococcus (5.4%), Aeromonas (5.2%), and Enterobacter (5.2%). In accordance with storage period and temperature, Pseudomonas grew on high ratio at 1$0^{\circ}C$ steadily, but Proteus had increased proportionally at 2$0^{\circ}C$ and 3$0^{\circ}C$. Additionally, Yeast, and Micrococcus had decreased by period.

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A Study on the Optimal Control Strategy of Air-Conditioning System with Slab Thermal Storage - The Difference by the Presence of Radiant Heat as a Criterion Factor - (슬래브축열의 최적제어방책에 관한 연구 -평가요소로 복사열의 고려 유무에 의한 차이-)

  • Jung Jae-Hoon;Shin Young-Gy
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.18 no.4
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    • pp.287-296
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    • 2006
  • In this paper, optimal control strategy of the air-conditioning system with slab thermal storage was investigated based on the optimal control theory. An optimal heat output to the plenum chamber and the air-conditioned room was determined based on two kinds of criterion functions. The first one requires small deviation in room air temperature from a set-point value and low energy consumption. It is shown that the optimized control is to store heat through the whole storage time and to increase storage rate gradually with time. As the second case, a criterion that both a deviation of operative temperature from a set-point temperature and the energy consumption should be minimized was adopted. The room air temperature was a little high and the cooling load during storage time was reduced, compared with the results when a criterion function considering only the room air temperature is used.

Changes in Quality Characteristics of Commercial Milk with Different Physical Treatments during Storage

  • Choi, Jinyoung;Kim, Youngsung;Kwon, Taeeun
    • Culinary science and hospitality research
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    • v.24 no.2
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    • pp.63-70
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    • 2018
  • In this study, the fatty acid content and quality characteristics of the massless enegy treated commercial milk products stored at $30^{\circ}C$ were investigated. The pH of pasteurized milk decreased significantly. UHT milk showed also significant decrease in pH to 4.70~5.72 on the 8th day of storage which was higher than control even there was no significant differences. The acidity of pasteurized milk decreased significantly from the 2nd day of storage to 0.13~0.65% in treatments and control and control was 0.94% at the 8th day of storage and 0.35% in the treatment of ultra high temperature milk. The solid content of pasteurized milk was $7.5^{\circ}Bx$ at 1 day after storage, which showed significant differences from the $11.2^{\circ}Bx$ in the treatment. Pasteurized milk showed more bacterial growth in the treatment than in the control. After 4 days of storage, there was no bacterial count in pasteurized milk but it increased significantly $1.9{\times}10^8$ and $4.5{\times}10^6$ each in UHT milk. Lactic acid bacteria were detected in the curd $2.0{\times}10^6$ in the control and $2.0{\times}10^8$ in the treatment at the 4th day. Palmitic acid content in the saturated fatty acid was the highest at 35.4~41.4% in both pasteurized and ultra high temperature milk. In the UHT milk, linolenic acid was significantly increased to 3.8% in the treatment compared with 2.9% in the control at the 4th day of storage. Therefore, commercial ultra high temperature milk with physical treatment to increase beneficial bacteria showed significant difference compared to the control after 5 days of storage in this experiment.

Analysis of PCM Wallboards Design Parameters using Dynamic Energy Simulation (동적 에너지 시뮬레이션을 이용한 PCM보드의 설계변수 분석에 관한 연구)

  • Lee, Jin-Uk;An, Sang-Min;Kim, Taeyeon;Lee, Seung-Bok
    • KIEAE Journal
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    • v.12 no.4
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    • pp.97-104
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    • 2012
  • A phase-change material is a substance with a high heat of fusion which, melting and freezing at a certain temperature, is capable of storing and releasing large amounts of energy. Heat is absorbed or released when the material changes from solid to liquid. Therefore, PCMs are classified as latent heat storage (LHS) units. The purpose of this study is to analyze PCM wallboard design parameters using dynamic energy simulation. Among the factors of PCM, melting temperature, latent heat, phase change range, thermal conductivity are very important element to maximize thermal energy storage. In order to analyze these factors, EnergyPlus which is building energy simulation provided by department of energy from the U.S is used. heat balance algorithm of energy simulation is conduction finite difference and enthalpy-temperature function is used for analyzing latent heat of PCM. The results show that in the case of melting temperature, the thermal energy storage could be improved when the melting temperature is equal to indoor surface temperature. It seems that when the phase change range is wide, PCM can store heat at a wide temperature, but the performance of heat storage is languished.

Experimental Study on the Effect of a Metal Storage Cask and Openings on Flame Temperature in a Compartment Fire

  • Bang, Kyoung-Sik
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.18 no.3
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    • pp.395-405
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    • 2020
  • Compartment fire tests were performed using kerosene and Jet A-1 as fire sources to evaluate the relationship between flame temperature and opening size. The tests were performed for a fire caused by the release of kerosene owing to vehicle impact, and for a fire caused by the release of Jet-A-1 owing to airplane collision. The compartment fire tests were performed using a 1/3-scale model of a metal storage cask when the flame temperature was deemed to be the highest. We found the combustion time of Jet-A-1 to be shorter than that of kerosene, and consequently, the flame temperature of Jet-A-1 was measured to be higher than that of kerosene. When the opening was installed on the compartment roof, even though the area of the opening was small, the ventilation factor was large, resulting in a high flame temperature and long combustion. Therefore, the position of the opening is a crucial factor that affects the flame temperature. When the metal storage cask was stored in the compartment, the flame temperature decreased proportionally with the energy that the metal storage cask received from the flame.

High Temperature Thermochemical Treatment and Characterization of Sepiolite for $CO_2$ Storage ($CO_2$ 저장용 Sepiolite의 고온 열화학처리 및 특성평가)

  • Choi, Weon-Kyung;Cho, Tae-Hwan
    • Journal of Hydrogen and New Energy
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    • v.17 no.4
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    • pp.425-433
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    • 2006
  • Sepiolite was selected as a mineral carbonation candidate ore for carbon dioxide sequestration. Carbonation salt formation from alkaline earth metal ingredient needs to dehydroxylation of sepiolite at high temperature. An evident dehydroxylation was observed over $800^{\circ}C$ and the variations of sepiolite characteristics after high temperature treatment was synthetically evaluated. Remarkable weight loss were measured after high temperature thermochemical reaction then crystallographic and spectroscopic changes were analyzed. The resulted alkaline earth metal oxides could explained by dehydroxylation based on thermochemical reaction.

Changes in Contents of Some Taste Compounds of Dried Mussel and Baby Clam during Storage (건조 홍합 및 바지락의 저장 중 핵산관련물질 및 유기염류의 변화)

  • Joo, Ok-Soo;Seo, Kwon-Il;Lee, Young-Soo;Lee, Jong-Ho;Choi, Sang-Do;Shim, Ki-Hwan
    • Korean Journal of Food Science and Technology
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    • v.28 no.5
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    • pp.882-887
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    • 1996
  • Some taste compounds such as nucleotide and their related compounds, trimethylamine oxide (TMAO), trimethylamine (TMA) and total creatinine of sea mussel and baby clam during drying at 40, 50 and 60^{\circ}C$ and storage at low temperature$(4^{\circ}C)$ and room temperature$(20^{\circ}C)$ were investigated. Six kinds of nucleotide and their related compounds such as adenine triphosphate (ATP), adenine diphosphate (ADP), adenine monophosphate (AMP), inosine, adenosine and hypoxanthine were analyzed. The contents od adenosine in raw sample was high in sea mussel and baby clam. The contents of ATP, ADP and AMP decreased, while those of inosine and hypoxanthine increased during drying and storage periods. The contents of TMAO, TMA and total creatinine were low in sea mussel and baby clam. TMAO and total creatinine decreased but TMA increased during drying and storage periods. The rate of change was high in room temperature storage and for long storage periods than that of low temperature storage and for short storage periods.

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Winter Season Performance Characteristics of Raw Water-Source Heat Pump System with a Thermal Storage Tank (원수열원 히트펌프 축열시스템의 동절기 성능분석)

  • Cho, Yong;Lee, Dong Keun
    • 한국신재생에너지학회:학술대회논문집
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    • 2011.05a
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    • pp.202-202
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    • 2011
  • Performance of the raw water-source heat pump system with a thermal storage tank has been analyzed in winter season. The raw water is transferred through the multi-regional water supply system from Han river. Raw water is large temperature difference resource compared with groundwater. Although the raw water temperature drops to $0.6^{\circ}C$ due to the heavy snowfall and the severe cold in late January and early February, 2010, the system has been normally operated without any trouble this winter. The unit COP and system COP considered all pump power consumption were estimated based on the second-by-second data of the all sensors. The monthly averaged unit COP and system COP are 3.37 and 2.76 respectively with $1.4^{\circ}C$ of raw water in January, 3.55 and 2.89 with $1.6^{\circ}C$ raw water in February, 3.82 and 3.15 with $5.4^{\circ}C$ raw water in March. The performance of the system are increased with raw water temperature, and the COPs are higher than the water-to-air heat pump system using relatively high temperature raw water from Daecheong reservoir because the water-to-water system was operated on the full load condition and was stopped when the thermal storage tank was full of the high temperature water.

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