• Title/Summary/Keyword: temperature stable

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The Stability of TPN Admixture of Amino acids Solution and Dextrose Solution (고영양수액요법에 빈용되는 아미노산수액제와 포도당액의 혼합시 안정성에 관한 연구)

  • Song, Mi Kyeong;Suh, Ok kyung;Lee, Suk Hyang;Lee, Sung Woo;Shin, Hyun Taek
    • Korean Journal of Clinical Pharmacy
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    • v.8 no.2
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    • pp.147-158
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    • 1998
  • The purpose of this study was to test the stability of TPN basic solutions containing amino acids and dextrose. Test solutions containing $4.25\%$ amino acids in $25\%$ dextrose (central TPN basic solution) or $4.25\%$ amino acids in $10\%$ dextrose (peripheral TPN basic solution) were prepared. Two different amino acids solutions $(Fravasol^{(R)}\;vs\;Freamine^{(R)})$ were tested. The samples were taken from each admixture and stored in the evacuated, sterile containers at $2{\sim}8^{\circ}C$ and ambient room temperature. Each sample was analyzed at 0, 3, 7, 14 and 30 days of storage. Each amino acid was analyzed by amino acid analyzer. Dextrose content was measured by polarimeter. The pH and chromagen formation were also monitored. The decomposition was measured by the changes in concentration of amino acids and dextroser TPN basic $solution-Freamine^{(R)}$ admixture stored at $2\sim8^{\circ}C$ were stable for 30 days. Central and peripheral TPN basic solutions stored at room temperature were stable for 7 days and 14 days, respectively. There were no changes in color for 30 days by naked eye. Amino acid concentrations in TPN basic $solution-Fravasol^{(R)}$ admixture stored at $2\sim8^{\circ}C$ or room temperature were stable for 30 days. But, significant color change was detected according to passing time. In conclusion, Peripheral TPN basic $solution-Fravasol^{(R)}$ admixture stored at room temperature and in refrigerator were stable for 3 days and 7 days, respectively. However, central TPN basic solution-Fravasol admixtures were unstable. Therefore, it is recommended that it should be admixed right before use.

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A Study on the Gasification of Combustible Waste (가연성 폐기물의 가스화에 관한 연구)

  • 정준화
    • Journal of Environmental Health Sciences
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    • v.16 no.2
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    • pp.89-95
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    • 1990
  • This study was investigated to the energy recovery by the pyrolysis of waste tyre. the pyrolysis of the waste tyre was made by using the pyrolysis chamber for the gasification and the combustion chamber for the combustion of the pyrolysis gas. In batch system, the amount of waste tyre was put 150kg in the pyrolysis chamber and the proper air flow rate for the stable production of the pyrolysis gas was 0.95Nm$^{3}$ /min. the production time of the pyrolysis gas was stable above 210minutes, and the stable production rate was above 3.8Nm$^{3}$ /min. The production temperature of pyrolysis gas was 170$^{\circ}$C and combustion temperature of pyrolysis gas was 1,000$^{\circ}$C. The combustible component of washing gas in pyrolysis gas of waste tyre was CO, CH$_{4}$, $C_{2}H_{6}$ and $C_{3}H_{8}$, and total amount was 22.7%. Heat value of condensed material was 9,804Kcal/kg. The average concentration of air pollutants between cyclone and scrubber was CO 420.4ppm, SO$_{x}$ 349.8ppm. NO$_{x}$ 68.Sppm, HCl 24.4ppm and Dust 240.0g / Nm$^{3}$, respectively.

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Development of a low NOx burner with honeycomb catalyst (저NOx형 하니컴 촉매버너의 개발)

  • Seo,Yong-Seok;Park, Byeong-Sik;Gang, Seong-Gyu
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.21 no.6
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    • pp.822-829
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    • 1997
  • A catalytic burner was studied which can be used as a heater operated in medium temperature. Noble metal catalysts (Pd/NiO) were used, which were supported on alumina wash coated honeycomb. The maximum heat-resisting temperature of the catalyst is about 900.deg. C. Combustion efficiency of the catalytic burner reached more than 99.5 % at the excess air ratio above 1.25.NOx emissions were lower than 1.0 ppm at all operation conditions. The operation condition for a stable catalytic combustion was obtained. It was dependent on the catalyst thickness. The 30 mm thick catalyst showed the widest stable catalytic combustion region. Stable catalytic combustion region of 30 mm thick catalyst was the operation condition of excess air ratio 1.25 - 1.75 and heat flux 7 - 14 kcal/h center dot cm$^{2}$.

A New Synthetic Route to Poly(benzimidazole) and the Related Model Reactions to Imidazoline and Benzimidazole

  • Shin, G. I.;Kim, Ji Heung
    • Bulletin of the Korean Chemical Society
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    • v.17 no.1
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    • pp.29-33
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    • 1996
  • Mono-, or di-substituted chlorodicyanovinyl benzene compound was reacted with an excess amount of ethylenediamine to give corresponding imidazoline product with high reaction yield. This reaction occurs by stable imidazoline ring-forming process through nucleophilic attack of terminal amine on the enaminonitrile adduct, the reaction intermediate, toward electropositive enamine carbon, which is accompanied by the release of neutral malononitrile moiety. The similar reaction with 1,2-phenylenediamine produced stable enaminonitrile-amine adduct at lower temperature which could be cyclized intramolecularly to thermally stable benzimidazole at elevated temperature in solution or in solid state. From the difunctional compound of both reactants, poly(enaminonitrile-amine) could be prepared as a new soluble precursor polymer for well-known polybenzimidazole (PBI). The thermal cyclization reaction accompanying the release of malononitrile molecules was studied using thermalanalysis and infrared spectroscopy.

A Study on Comparison of Capacity between Wet.Dry Floor Heating Systems Using Geothermal Heat Pump (지열히트펌프를 이용한 습식.건식 바닥난방 성능평가 연구)

  • Lee, Byoung-Doo;Lee, Se-Jin;Lee, Dae-Woo;Oh, Sung-Hae;Nam, Woo-Dong
    • 한국신재생에너지학회:학술대회논문집
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    • 2009.11a
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    • pp.567-570
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    • 2009
  • The present study conducted comparative evaluation of wet dry floor heating systems using geothermal heat pump. Circulation hot water from geothermal heat pump which is $10{\sim}15^{\circ}C$ lower than that from boiler was used. In order to access indoor temperature ($25^{\circ}C$) it took 74 minutes for dry type and 247 minutes for wet type. Average floor temperature was $23.89^{\circ}C$ for wet type and $32.66^{\circ}C$ for dry type. Energy saving rate gradually increased by 66% after 138 minutes. In the results, for floor heating system using low temperature circulation water, wet type was not enough to meet stable and comfortable radiant floor heating due to low floor temperature and access time to indoor set temperature. While dry type was practicable for stable floor heating due to fast rise of indoor set temperature and comfortable floor temperature.

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Investigation of the Carrier Lifetime of Cz-Si after Light Induced Degradation (빛에 의한 Cz 실리콘 기판의 carrier lifetime 감소에 대한 연구)

  • Lee, Ji-Youn;Lee, Soo-Hong
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.07b
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    • pp.985-988
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    • 2004
  • The carrier lifetime of boron doped Cz silicon samples after light induced degradation could be improved by optimized rapid thermal processing (RTP). The important five different parameters varied in order to investigate which parameter is important for the stable lifetime after light induced degradation, $\tau_d$. The Plateau temperature and the Plateau time influenced on the lifetime after light induced degradation. Especially, the Plateau temperature showed a strong influence on the stable lifetime. The optimal plateau temperature is approximately $900^{\circ}C$ t for a plateau time of 120 s. The stable lifetime increased from $15\mu}s$ to $25.5{\mu}s$. The normalized defect concentration, $N_t^*$, decreased from $0.06{\mu}s^{-1}$ to $0.037{\mu}s^{-1}$ by RTP-process.

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Study on the Characteristics of Cylinder Wake Placed in Thermally Stratified Flow(III) - Turbulent Dispersion from a Line Heat Source- (열성층유동장에 놓인 원주후류의 특성에 대한 연구 (3) -선형열원으로부터의 난류확산-)

  • 김경천;정양범
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.5
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    • pp.1300-1307
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    • 1995
  • The effect of thermal stratification on the turbulent dispersion from a fine cylindrical heat source was experimentally examined in a wind tunnel with and without a strong temperature gradient. A 0.5 mm dia. nichrome wire was used as a line heat source. Turbulent intensities, r.m.s. value of temperature and convective heat fluxes were measured by using a hot-wire and cold-wire combination probe. The results show that the peack value and the spread of the vertical turbulent intensity for the stratified case are far lower than those in the neutral case, which indicates that the stable temperature gradient suppresses the vertical velocity component. All of the third order moments including heat fluxes measured in the stable condition have very small values than those of the neutral case. This nature suggests that the decrease of scalar fluctuations in the stably stratified flow is mainly due to the suppression ofthe turbulent diffusion processes by the stable stratification. A simple gradient model with a composite timescale which has a simple weighted algebraic mean between dynamic and thermal time scale yields reasonably good numerical values in comparison with the experimental data.

Interfacial Characteristics of $\beta$-SiC Film Growth on (100) Si by LPCVD Using MTS (MTS를 사용한 LPCVD 법에 의한 (100)Si 위의 $\beta$-SiC 증착 및 계면특성)

  • 최두진;김준우
    • Journal of the Korean Ceramic Society
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    • v.34 no.8
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    • pp.825-833
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    • 1997
  • Silicon carbide films were deposited by low pressure chemical vapor deposition(LPCVD) using MTS(CH3SICl3) in hydrogen atmosphere on (100) Si substrate. To prevent the unstable interface from being formed on the substrate, the experiments were performed through three deposition processes which were the deposition on 1) as received Si, 2) low temperature grown SiC, and 3) carbonized Si by C2H2. The microstructure of the interface between Si substrates and SiC films was observed by SEM and the adhesion between Si substrates and SiC films was measured through scratch test. The SiC films deposited on the low temperature grown SiC thin films, showed the stable interfacial structures. The interface of the SiC films deposited on carbonized Si, however, was more stable and showed better adhesion than the others. In the case of the low temperature growth process, the optimum condition was 120$0^{\circ}C$ on carbonized Si by 3% C2H2, at 105$0^{\circ}C$, 5 torr, 10 min, showed the most stable interface. As a result of XRD analysis, it was observed that the preferred orientation of (200) plane was increased with Si carbonization. On the basis of the experimental results, the models of defect formation in the process of each deposition were compared.

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Stabilities of Anthocyanin Pigmenta obtained from Crab Apple (Malus prunifolia Wild. Borkh. "Red Fruit") by Ethanol Extraction (꽃사과(Malus prunifolia Wild. Borkh. "Red Fruit")에서 에탄올 추출한 안토시안 색소의 안정성)

  • 김용환
    • The Korean Journal of Food And Nutrition
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    • v.12 no.1
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    • pp.85-90
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    • 1999
  • The characcteristics of anthocyanin pigments from crab apple (Malus prunifolia Wild. Borkh. "red fruit") by ethanol extract were investigated at various condition of light temperature sugar, organic acid me-tal ion and pH. The pigments were stable(over the 60%) on the light irradiation throughout 20 days sto-rage period at room temperature and in the pesenc of Al-foil red blue green and yellow cover were rage period at room temperature and in the pesence of Al-foil red blue green and yellow cover were very stable. The pigments also showed high thermal stbility(over the 67% at 115$^{\circ}C$ 10min) at pH2.5 respectively. The pigments with added organic acid greatly increased thickness of red color. The pig-ments with added metal ions at pH 2.5 such as Na+ K+, Mg2+ Ca2+ and Mn2+ were stable throughout 20 days storage period at $25^{\circ}C$. But Cu2+ addition showed the rapidly degradation of the pigments and Al3+ addition induced the color conversion from red to redish violet. The thickness of the red color of anthocyanin pigments increased increased as the pH decreased. These results indicated that crab apple antho-cyanin pigments might be potental source of natural food colorant. colorant.

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Characteristics of Nocturnal Boundary Layer Observed in Kyungpook Province (경북지역에서 관측된 야간 대기경계층의 특성)

  • Byung-Hyuk Kwon
    • Journal of Environmental Science International
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    • v.10 no.5
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    • pp.329-336
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    • 2001
  • Characgcteristics of nocturnal boundary layer(NBL) were analyzed by the upper-air observations data using with the airsonde and pilot balloons from 1994 to 1999 in Kyungpook province. The automate weather boundary layer can become stably stratified when the surface is cooler than the air. Stable nocturnal boundary layer height were estimated from the top of surface stable layer where the vertical gradient of temperature and mixing ratio tend to zero or negative. The depth of the stable nocturnal boundary layer depended largely on the thermal effect rather than the wind effect at nighttime. The NBL was more developed on the land than on the coastal region. The stability index (bulk Richardson number) showed that the NBL was stable when the wind was weak and the vertical gradient of the temperature was strong. The heat budget in the NBL was studied by considering the effect of the radiative and the cooled by both the longwave radiative flux and the divergence of the heat flux, while NBL under the cloudy sky the longwave radiative flux played a role of the warming. It was noted that the heat was not conserved in both cases. To complete the heat budget in the NBL the warming/cooling by advection and subsidence must be considered.

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