• Title/Summary/Keyword: Moisture Resistant

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Formation of Enzyme Resistant Starch by Extrusion Cooking of High Amylose Corn Starch (고아밀로즈 옥수수전분의 압출성형에 의한 난소화성화)

  • Kim, Ji-Yong;Lee, Cherl-Ho
    • Korean Journal of Food Science and Technology
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    • v.30 no.5
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    • pp.1128-1133
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    • 1998
  • Extrusion cooking treatment was compared with autoclaving/cooling treatment for formation of enzyme resistant starch of high amylose corn starch (HACS). Effects of barrel temperature $(100^{\circ}C,\;120^{\circ}C,\;140^{\circ}C)$ and feed moisture content (25%, 35%, 45%) on extrusion processing in a co-rotating twin-screw extruder under fixed screw speed (100 rpm) were investigated by measuring enzyme resistant starch (RS) yield. RS yield were estimated by in-vitro pancreatin digestion method and enzymatic-gravimetric method using termamyl. Barrel temperature and yield of RS were negatively correlated and feed moisture content and yield of RS was positively correlated as determined by in-vitro pancreatin method. The highest yield (38.4%) of RS was obtained from HACS extrudate processed at the barrel temperature of $100^{\circ}C$ and the feed moisture content of 45%, while the yield of RS by 5 times of autoclaving/cooling was 25%. The yield of RS by in vitro pancreatin digestion method was 20.7% with high amylose corn starch and 8.2% with ordinary corn starch (CS), respectively, under the same extrusion condition (barrel temperature $120^{\circ}C$, feed moisture content 35%). At the same condition, the yields of RS by enzyme-gravimetric method were 14.6% with HACS and 6.8% with CS, respectively. The yield of RS increased during the storage at $4^{\circ}C$ for 4 weeks and the highest yield (60%) was obtained by the storage of HACS extrudates extruded at $100^{\circ}C$ and 45% feed moisture content.

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The Effect of Spacer on Microclimate and Comfort Sensation in Protective Clothing for Firefighters

  • Chung, Gi-Soo;Lee, Dae-Hoon
    • Fashion & Textile Research Journal
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    • v.4 no.6
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    • pp.564-566
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    • 2002
  • Protective clothing for firefighters typically consists of a flame resistant outer shell and inner layers. The inner layers are generally composed of a moisture barrier and a thermal barrier. On performing the task in fire place the heat and perspiration generated from the body become trapped inside the protective clothing. Those heat and moisture result into heat-stress and physical fatigue of fire fighter, which hinder the work. Therefore, the system of clothing designs and material layers must be chosen carefully to balance protection and comfort. 3 kinds of protective clothing of 3 layer structure were used in the experiment of physiological comfort. From the comparison of wear trials with the 3 kinds of layers in firefighters clothing, it indicates that the moisture dissipation of A+B2+C was highest, following A+BI+C andA+B3+C. And the heat dissipation of A+BI+C and A+B2+C were better than A+B3+C. In the protective clothing with A+B3+C, heat and perspiration generated through exercise remained in clothing system long and caused discomfort.

Evaluation of Moisture Susceptibility of Porous Hot Mixed Asphalt Mixtures with Hydrated Lime using Non-destructive Impact Test (비파괴 충격파 시험을 통한 소석회 첨가 투수성 가열 아스팔트 혼합물의 수분민감성 평가)

  • Kim, Dowan;Mun, Sungho
    • International Journal of Highway Engineering
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    • v.17 no.4
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    • pp.77-87
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    • 2015
  • PURPOSES: It is theoretically well known all over the world, that porous hot mixed asphalt (HMA) with hydrated Lime improves moisture and rutting resistance, and reduces pothole occurrence frequency, as well as the life cycle cost (LCC). METHODS : Addictive in the two different formations of the liquid anti-stripping Agent and powder Hydrated-Lime was applied in this investigation in order to obtain relatively clear results according to their types and conditions. Firstly, the moisture conditions were set, and applied to the porous HMA mixtures with hydrated lime (anti-stripping agent). Next, it was followed by a non-destructive test with the application of three freeze-thaw cycles, which were individually carried out thrice to compare the results of the dynamic moduli. Lastly, the hydrated lime effect related to moisture sensibility to porous HMA has been verified through the analysis of the modulus results regarding the change rate of dynamic modulus per n-cycle. RESULTS: It is clear from this investigation, that the dynamic modulus is inversely proportional to the change in temperature, as the graph representing the rigidity of the thermorheologically simple (TRS) material showed gradual decline of the dynamic modulus with the increase in temperature. CONCLUSIONS: The porous HMA mixture with the anti-stripping agent (hydrated Lime) has been found to be more moisture resistant to freezing and thawing than the normal porous HMA mixture. It is clear that the hydrated lime helps the HMA mixture to improve its fatigue resistance.

Studies on the Wet-injury Resistance of Wheat and Barley Varieties III. Effect of Various Moisture Levels on the Top and Root Growth of Barley Crop (맥류 내습성에 관한 연구)

  • Hyung-Soo Suh
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.22 no.2
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    • pp.80-92
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    • 1977
  • This experiment investigated the effect of various moisture levels on the top and root growth of barley and its yield. Resistant varieties to excess moisture injury shortened plant height, but tillered more, having creeping plant type compared with ordinary one, and greater portion of root of this varieties occured at the deeper soil depths with longer root length. However, susceptible one to excess moisture injury showed an inversed trend when compared with the untreated one. Oversaturated treatment compared with the untreated increased a little bit soil temperature and Eh of soil. Increased root activity and increased yield were obtained with resistant varieties compared with the untreated. Lower root activity and less yield than those of the untreated were observed in both extreme treatments. Yield reduction in both the extreme treatments was mainly due to reduction of tiller number, grain number and 1, 000-grain weight. Highest yield reduction was marked at the stage of internode elongation in the oversaturated and at the booting stage in the overdried treatment.

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Changes in Quality Characteristics of Jeungpyun containing different Levels of Malt Extract during Storage (엿기름 추출액의 첨가량에 따른 증편의 저장 중 품질 특성 변화)

  • Jung, Kyoung-Wan;Kim, Yoo-Kyung;Lee, Gui-Chu
    • Journal of the Korean Society of Food Culture
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    • v.26 no.5
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    • pp.521-529
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    • 2011
  • This study evaluated the effects of different levels of malt extract on the hardness, moisture, water soluble starch (WSS) contents, and in vitro starch digestibility (IVSD) of Jeungpyun during storage at room temperature ($25{\pm}1^{\circ}C$) and refrigeration temperature ($4{\pm}1^{\circ}C$). Resistant starch (RS) and soluble starch (non-RS) contents were also evaluated. During storage at both temperatures, hardness increased in Jeungpyuns with the malt extract-added Jeungpyun groups (malt-added Jeungpyuns) exhibiting lower hardness than the control. The rate of retrogradation was faster upon storage at refrigeration temperature. Moisture and WSS contents as well as IVSD of Jeungpyuns decreased, whereas these levels were higher in malt-added Jeungpyuns compared to control. Storage increased RS contents in Jeungpyuns stored for up to 4 days, particularly at $4^{\circ}C$, whereas there was a decrease in RS content after 7 days of storage. However, RS content was lower in malt-added Jeungpyuns compared to control. Soluble starch (SS) contents of Jeungpyuns decreased. However, SS content was higher in malt-added Jeungpyuns than that of control. The reduced hardness and RS content as well as the rate of increase in other parameters of malt-added Jeungpyuns were dependent on the concentration of malt extract. These results reveal that addition of malt extract delayed retrogradation of Jeungpyun, whereas retrogradation possibly increased the content of RS during storage at both temperatures, however, that of RS decreased with increasing level of malt extract, suggesting that the level of malt extract as well as the storage conditions are important for obtaining acceptable texture and retaining the RS content of Jeungpyun, which is known to possess physiological activity.

Water Resistance Evaluation of the Oils Coating for Conservation of Wooden Cultural Heritage (목조문화재 보존을 위한 유지류 코팅제의 방수 성능 평가)

  • Na, Won Ju;Cho, So Yeong;Kim, Do Rae;Chung, Woo Yang
    • Journal of Conservation Science
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    • v.31 no.1
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    • pp.13-20
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    • 2015
  • Surface of the wooden cultural heritage has been protected from moisture by natural oils (such as perilla oil and tung oil), which accelerated degradation. But we can find seldom the research on the processes and performances of oil coatings. In this study, the water resistant performances by wood direction were compared to 3 types of natural oil and 2 types of oil stain, and the effect of additional indoor conditioning and temperature of oil were appraised in longitudinal direction. The natural oils block moisture about 79.2% comparing to the control in longitudinal direction. Especially the tung oil showed the outstanding water resistance about 90.5%. The water resistant performances decreased about 8.8% by additional indoor conditioning for 2 years. Heated oil improved the water resistance about average 5.0%.(Max. 9.6% with linseed oil).

Simple Fabrication of Green Emission and Water-Resistant CsPbBr3 Encapsulation Using Commercial Glass Frits (상업용 유리프릿의 소결 공정을 이용한 내수성을 갖는 CsPbBr3/Glass 세라믹 복합체의 제작)

  • Mun, Na-eun;Kim, Sunghoon
    • Korean Journal of Materials Research
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    • v.31 no.1
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    • pp.54-59
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    • 2021
  • In this work, narrow-band green-emitting CsPbBr3 particles are embedded in commercialized glass composites by a facile dry process. By optimizing the method through sintering in glass frit (GF) composites including CsBr and PbBr2, used as precursors, the encapsulation of CsPbBr3 particles made them waterproof with green fluorescence. To improve the fluorescent properties by reducing aggregation of CsPbBr3, fumed silica (FS) is additionally used to help particles avoid bulking up in the glass matrix. The CsPbBr3 perovskite/glass composites are characterized using scanning electron microscopy (SEM) images and energy-dispersive X-ray spectroscopy (EDS) maps, which support the existence of CsPbBr3 particles in the glass matrix. The photoluminescence (PL) properties demonstrate that the emission spectrum peak, full width at half maximum (FWHM), and photoluminescence quantum yield (PLQY) values are 519 nm, 17 nm, and 17.7 %. We also confirm the water-resistant properties. To enhance water/moisture stability, the composite sample is put directly into water, with its PLQY monitored periodically under UV light.

A Study on the Analysis of Fire Mechanisms in Electronic Products due to Failure and Malfunction of Thermostats Through Fire Cases and Reproduction Experiments (화재사례 및 재현실험을 통한 온도조절장치 고장 및 오동작으로 인한 전자제품 화재 메커니즘 분석)

  • Jeong-il Lee;Jong-Hwa Im
    • Journal of the Korea Safety Management & Science
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    • v.26 no.1
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    • pp.31-38
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    • 2024
  • In this paper, as there are many cases of fires occurring due to the failure or inoperability of the thermostat of electronic products, the purpose is to test and analyze the risks and probabilities through fire cases and reproduction experiments, and suggest countermeasures. Among electronic products, water purifiers are composed of a refrigerant system with a compressor to make cold water, a heating device to make hot water, and an electric device used as an energy source. Due to the nature of the water purifier manufacturing, these devices are subject to a lot of moisture and dust. etc. exist in large quantities and use electrical energy, so there is a possibility of fire due to short circuit in the wire, electrical abnormal overheating (tracking phenomenon) in the thermostat, electronic board, starting relay, etc., and overheating of the heating device (Band Heater). there is. Therefore, in order to prevent fires from these devices, a system to remove foreign substances inside the water purifier is necessary, the use of heat-resistant (fire-resistant) wires for electrical devices is essential, and the use of non-combustible materials (semi-combustible materials) for each part is necessary to prevent fire. The risk must be eliminated through prevention and combustion expansion prevention devices.

Changes of the Physical Properties of Corrugated Fiberboard Boxes for Fruit and Vegetable Packaging by Preservation Temperature and Relative Humidity (과채류 포장용 골판지 상자의 저장온도와 습도에 따른 물리적 특성 변화)

  • Lee, Myung-Hoon;Cho, Jung-Yeon;Shin, Jun-Seop
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.34 no.1
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    • pp.46-53
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    • 2002
  • This study was carried out to analyze the effects of preservation temperature and relative humidity to the physical properties of corrugated fiberboard boxes for fruit and vegetable packaging. The preservation temperature did not affect severely to physical properties of corrugated fiber-board. Relative humidity was a major cause of corrugated fiberboard box quality deterioration. The burst and compressive strengths of experimental boxes measured with Mullen high pressure tester and tong crush tester were decreased gradually as relative humidity increased from 55% to 75%. But, the strength properties slightly decreased relative humidity at 75% or higher. This tendency was the greater for single wall (SW) corrugated fiberboard box than that for double wall (DW). It is suggested that development of the water-resistant corrugated fiberboard and box be needed that can be used under the condition of low temperature and high moisture content, which are being employed in the cold chain system.

Strength Changes of Corrugated Fiberboard Boxes for Fruits Packaging by Relative Humidity Temperature (과실포장용 골판지 상자의 온습도에 따른 강도 변화)

  • Jo, Jung-Yeon;Min, Choon-Ki;Shin, Jun-Seop;Lee, Myung-Hoon;Sohn, Ki-Zoo
    • KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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    • v.7 no.2
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    • pp.43-51
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    • 2001
  • This study was carried out to analyze changes of the physical properties of corrugated fiberboard boxes for fruits packaging by various moisture and temperature changes. There were significant decrease in burst strength with increased relative humidity. And also compressive strength(ring crush test) of corrugated fiberboard and box were reduced with moisture content. The decreasing amounts of single wall(SW) corrugated fiberboard was bigger than that of double wall(DW). The physical properties reductions of corrugated fiberboard and box were mainly affected by relative humidity. Therefore, it is suggested that development of the water-resistant corrugated fiberboard and box be useful under the condition of low temperature and high relative humidity such as the cold chain system.

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