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The study for selecting an appropriate value of input capacitor in dispersed generation PV inverter

  • Lee K.S.;Jung Y.S.;So J.H.;Yu G.J.;Choi J.H.;Choi J.Y.
    • Proceedings of the KIPE Conference
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    • 2003.07b
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    • pp.495-498
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    • 2003
  • Most PV (Photovoltaic) inverters are a voltage source type. Normally an input capacitor of this type is connected at the input of an inverter to keep the DC voltage constant. However, it does not seem to be well known how to determine the appropriate value of the capacitor. By developing non-linear transient analysis, the author suggests a guideline fur this approach. An implicit trapezoidal formula was used to do this calculation.

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TIGHTENED CRITICAL VALUE DEGRADATION TEST

  • Jang, J.S.;Jang, S.J.;Park, B.H.;Lim, H.K.
    • Proceedings of the Korean Reliability Society Conference
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    • 2004.07a
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    • pp.193-200
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    • 2004
  • Determination of sample sizes and the inspection intervals for degradation tests is considered. The cases of degradation rate model and degradation path model are analyzed with some examples. Tightened critical value tests are also considered that are shown to be advantageous over non-tightened ones.

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Change of Free Amino Acid and Nucleotide Compound of Puffer Fish Fillet under Storage Condition (저장조건에 따른 복어육의 유리아미노산 및 핵산 화합물의 변화)

  • Mun, Seung-Kweon;Sung, Ki-Hyup;Yoo, Seung-Seok
    • Korean journal of food and cookery science
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    • v.28 no.3
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    • pp.249-255
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    • 2012
  • The objectives of this study were to evaluate the physicochemical characteristics of puffer fish under storage conditions. Free amino acids were identified in the order of taurine > alanine > lysine > leucine > glutamic acid > valine. Glutamic acid, lysine, histidine, arginine, proline, and aspartic acid increased over time and with increased temperature, and valine and tyrosine were affected by temperature. ATP decreased dramatically during 36 h of storage at $4^{\circ}C$, 24 h of storage at $12^{\circ}C$, and 16 h of storage at $20^{\circ}C$. IMP reached its highest level when puffer fish was stored for 36 h at 4 and $12^{\circ}C$ and 24 h at $20^{\circ}C$, and hypoxanthine levels grew steeply at 60 h at $4^{\circ}C$, 24 h at $12^{\circ}C$ and 20 h at $20^{\circ}C$. In terms of K value, the puffer fish was available for sliced raw fish within 60 h at $4^{\circ}C$, 24 h at $12^{\circ}C$ and 12 h at $20^{\circ}C$, and the fish can be taken in after cooking within 72 h at $4^{\circ}C$ and $12^{\circ}C$ and 36 h at $20^{\circ}C$. The physicochemical quality characteristics showed that puffer fish is available for sliced raw fish within 36 h at $4^{\circ}C$, 16 h at $12^{\circ}C$ and 12 h at $20^{\circ}C$, and that the fish can be taken after cooking within 72 h at $4^{\circ}C$ and $12^{\circ}C$ and 36 h at $20^{\circ}C$.

A Study of the Foaming Properties of Peanut Protein Isolate (분리 땅콩 단백질의 기포 특성에 관한 연구)

  • Park, Hyun-Kyung;Sohn, Kyung-Hee;Kim, Hyon-Jung
    • Korean journal of food and cookery science
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    • v.6 no.3 s.12
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    • pp.9-15
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    • 1990
  • Peanut prptein isolate was tested for the purpose of finding out the effect of pH, Sodium Chloride concentration and heat treatment on the solubility, surface hydrophobicity, foam expansion and foam stability. The solubility of peanut protein isolate was affected by pH and showed the lowest value at pH 4.5. When the peanut protein isolate was heated, the solubility decreased at pH 3 and pH 7 but at pH 9 solubility increased. At all pH range, solubility decreased as NaCl was added. The surface hydrophobicity of peanut protein isolate showed the highest value at pH 1.5. Generally, at acidic pH range the surface hydrophobicity was high, but at alkaline region, the surface hydrophobicity increased as the temperature increased. And when NaCl was added, the surface hydrophobicity was also increased. Foam expansion of peanut protein isolate was no significant difference among the values about pH. When the peanut protein was heated and NaCl was added, foam expansion was increased at pH 7. Foam stability was significantly low at pH 4.5 and foam stability was increased at acidic pH region below pH 4.5. At pH 7 and pH 9, heat treatment above $60^{\circ}C$ increased foam stability. When NaCl was added, foam stability was significantly increased at pH 3 and pH 7.

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A Comparison Study on Functional Properties of Peanut Protein and Chemically Modified Peanut Protein (분리 땅콩 단백질과 화학적으로 수식화한 단백질간의 식품학적 특성 비교)

  • Sohn, Kyung-Hee;Min, Sung-Hee;Park, Hyun-Kyung;Park, Jin
    • Korean journal of food and cookery science
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    • v.7 no.2
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    • pp.97-104
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    • 1991
  • This study was carried out in order to study the protein functionality such as foaming and emulsifying properties by succinylation of peanut protein isolates. Succinylated and unsuccinylated peanut protein isolate was tested for to find out the effect of pH, heat treatment and sodium chloride concentration on the solubility, foam expansion, foam stability, emulsion capacity and emulsion stability. The results are summarized as follows; 1. Succinylation enhanced the solubility of peanut protein isotate (PPI). The solubility of succinylated PPI markedly increased at pH 4.5. When the protein solutions was heated, the solubility of succinylated PPI greatly increased than PPI at pH 3. With addition of NaCl, solubility of succinylated PPI increased at pH 7 and pH 9. 2. The foam expansion of PPI and succinylated PPI on pH was no difference between both proteins. Addition of NaCl and heat treatment caused steeply increased in foam expansion at pH 3. 3. The foam stability of PPI and succinylated PPI showed the lowest value at pH 4.5. When PPI and succinylated PPI was heated, foam stability of two proteins incensed at pH 3 and showed similar aspects between PPI and succinylated PPI. However, at pH 9 stability of succinylated PPI decreased by heat treatment over $60^{\circ}C$. 4. Emulsion capacity of succinylated PPI on pH was markedly increased and showed the highest value at pH 11. At pH 4.5 which is isoelectric point of PPI, emulsion capacity of PPI by succinylation improved than that of PPI. When succinylated PPI was heated, emulsion capacity was greatly increased at pH 2 and pH 7. With NaCl was added, emulsion capacity of succinylated PPI increased than that of PPI. 5. Emulsion stability of PPI and succinylated PPI was affected by pH and showed its highest value at pH 11. At pH 4.5, emulsion stability of succinylated PPI increased than that of PPI. Addition of NaCl and heat treatment caused slightly increased in emulsion stability of succinylated PPI.

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Emulsifying and Rheological Properties of the Pine Nut's Extracts (잣 구성 성분의 유화 및 유동특성)

  • Lee, Seog-Won;Rhee, Chul
    • Korean Journal of Food Science and Technology
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    • v.32 no.5
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    • pp.1093-1101
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    • 2000
  • The effects of concentration and pH on the emulsifying and rheological properties of the pine nut's protein extract(PNPE) and carbohydrate extract(PNCE) were investigated. Emulsifying activity index(EAI) of sample containing PNPE was minimal at pH 4.0 and the alteration of pH from 4 to 3 or 8 increased EAI regardless of concentration. The most EAI(about 6.44 $m^2/g$ solid) significantly(p<0.05) observed in solution containing 1% PNPE at pH 8.0, but that of 3% PNPE(0.10 $m^2/g$ solid) was minimal at pH 4.0. The emulsion stability exhibited maximum value(about 20) in 3% PNPE emulsion at pH 8.0. However, EAI of samples containing PNCE increased gradually with the increase of pH, but it had lower value than that of samples containing PNPE. At pH 7.0 and 8.0, the rheological behavior of emulsion solutions showed Newtonian fluid(n=1, $r^2>0.99$) regardless of concentration in all samples containing PNPE, but the samples containing PNCE showed pseudoplastic behavior(n<1) in all conditions. The sample with the better emulsion stability index(ESI) significantly(p<0.05) exhibited the higher L, b, and ${\delta}E$, however, lower a value.

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A Simplified Method to Consider Forming Effects in a Car Crash Analysis (차량충돌해석 적용을 위한 간단화한 성형이력 고려 방법)

  • Huh, J.;Yoon, J.H.;Lim, J.H.;Park, S.H.;Huh, H.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2008.10a
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    • pp.259-262
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    • 2008
  • This paper introduces a simplified method to consider forming effects in a car crash analysis. Representative value was used to consider forming effects simply. Four representative values, which are the mean value of thicknesses and effective plastic strains at nodes, the median of thicknesses and effective plastic strains at nodes, were evaluated. A crash analysis of a front side member shows that analysis results from the suggested methods are similar to those from the conventional method to consider forming effects. Use of the mean effective plastic strain shows the best results. A car crash analysis for a ULSAB/AVC model under the condition of US SINCAP were carried out to demonstrate the validity of the suggested method. Analysis results show that the error of suggested method is less than 1.5%.

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Study on the Preparation of Kochujang with Utilization of Retrogradated Starch food (노화된 전분식품을 이용한 고추장 제조에 관한 연구)

  • 차은정;김경자
    • Korean journal of food and cookery science
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    • v.12 no.4
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    • pp.481-486
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    • 1996
  • This study was compared with conventional kochujang and the preparation of saccharification kochujanf with the utilization of waste cooked rice, rice cake, bread. Saccharification kochuiang tested to estimated the pH, reducing sugar and changes of organic acid conients, sensory evaluation during the aging at 60 days. Moisture content were increased about B-10% nd crude fat contents were decreased about 20-40% during the aging at 60 days. Change of pH value of kochujang reduces gradually from pH 5.0 up to pH 4.7 during the aging. Total reducing sugar contents of saccharification kochujang reached maximum value at 50 days. The Products of organic acids of during aging were acetic acid, lactic acid, malic acid, tartaric acid and citric acid of the chief of source. Sensory evaluation conducted by fifteen students as panelists showed that were at 1% level significant difference 7 samples in color, flavour, apperance.

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