• Title/Summary/Keyword: temperature reducing effect

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Antioxidant Activity of Yogurt Fermented at Low Temperature and Its Anti-inflammatory Effect on DSS-induced Colitis in Mice

  • Yoon, Ji-Woo;Ahn, Sung-Il;Jhoo, Jin-Woo;Kim, Gur-Yoo
    • Food Science of Animal Resources
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    • v.39 no.1
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    • pp.162-176
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    • 2019
  • This study was performed to evaluate the antioxidant activity of yogurt fermented at low temperature and the anti-inflammatory effect it has on induced colitis with 2.5% dextran sodium sulfate (DSS) in Balb/c mice. Yogurt premix were fermented with a commercial starter culture containing Lactobacillus acidophilus, Bifidobacterium lactis, Streptococcus thermophilus, and Lactobacillus delbrueckii subsp. bulgaricus at different temperatures: $22^{\circ}C$ (low fermentation temperature) for 27 h and $37^{\circ}C$ (general fermentation temperature) for 12 h. To measure antioxidant activity of yogurt samples, DPPH, $ABTS^+$ and ferric reducing antioxidant potential (FRAP) assays were conducted. For animal experiments, inflammation was induced with 2.5% DSS in Balb/c mice. Yogurt fermented at low temperature showed higher antioxidant activity than that of the yogurt fermented at general temperature. In the inflammatory study, IL-6 (interleukin 6) was decreased and IL-4 and IL-10 increased significantly in DSS group with yogurt fermented at general temperature (DYG) and that with yogurt fermented at low temperature (DYL) compared to that in DSS-induced colitic mice (DC), especially DYL had higher concentration of cytokines IL-4, and IL-10 than DYG. MPO (myeloperoxidase) tended to decrease more in treatments with yogurt than DC. Additionally, yogurt fermented at low temperature had anti-inflammatory activity, although there was no significant difference with general temperature-fermented yogurt (p>0.05).

Effect of Lowered and Cycled Storage Temperature of Rice Cooker (낮고 반복된 저장 온도의 밥솥에서 밥의 색 및 미생물 성장에 미치는 효과)

  • Na, Hye-Jung;Ryu, Dong-Kul;Lee, Yun-Gi;Oh, Yong-Taek;An, Gil-Hwan
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.38 no.7
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    • pp.958-963
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    • 2009
  • To improve the quality of boiled rice after storage in rice cookers, temperature was controlled at a lowered condition ($45{\sim}65^{\circ}C$ repeated temperature cycling), compared to the present commercial rice cookers ($75^{\circ}C$). The effect of lowered temperature cycling on the microbial growth, color of rice, and reducing sugar production was measured. The bacteria Bacillus cereus and B. subtilis were killed at $75^{\circ}C$ and $45{\sim}65^{\circ}C$ cycling. The temperature cycling at $45{\sim}65^{\circ}C$ prevented an increase in colony forming unit of E. coli more than the steady temperature at $75^{\circ}C$. Browning during storage was significantly decreased at $45{\sim}65^{\circ}C$ cycling, compared to $75^{\circ}C$. The yellowness increase (${\Delta}b$ value of CIE parameters of the colorimeter) after the 3-day storage was 2.18 at $45{\sim}65^{\circ}C$ cycling whereas 9.12 at $75^{\circ}C$. Reducing sugar was not produced at $75^{\circ}C$ and $45{\sim}65^{\circ}C$ cycling but produced at $30^{\circ}C$ because of the microbial growth. In conclusion, the temperature cycling at $45{\sim}65^{\circ}C$ can improve the quality of stored boiled rice by decreasing the browning and inhibiting the microbial growth.

A Study on the factors of Quality variation for High Flowing Concrete in Site (고유동 콘크리트의 품질변동 요인에 관한 연구)

  • Kwon Yeong-Ho;Lee Hyun-Ho;Lee Hwa-Jin;Ha Jae-Dam
    • Proceedings of the Korea Concrete Institute Conference
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    • 2004.11a
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    • pp.743-746
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    • 2004
  • This research investigates experimentally an effect on the properties of the high flowing concrete according to variations of concrete materials and site conditions. Variations of sensitivity test are selected items as followings; (1)Concrete temperature, (2)Unit water(Surface moisture of fine aggregate), (3)Fineness modulus of fine aggregate, (4)Addition ratio of high-range water reducing agent. And fresh conditions of the high flowing concrete should be satisfied with required range including slump flow$(65{\pm}5cm)$, 50cm reaching time of slump flow$(4\~10sec)$, V-box flowing time$(10\~20sec)$, U-box height(min.300mm) and air content$(4{\pm}1\%)$. As results of sensitivity test, material variations and site conditions should be satisfied with the range as followings; (1)Concrete temperature is $10\~20^{\circ}C$ (below $30^{\circ}C$), (2)Surface moisture of fine aggregate is within ${\pm}0.6\%$, (3)Fineness modulus of fine aggregate is $2.6{\pm}0.2$ and (4)addition ratio of high range water reducing agent is within $1\%$ considered flow-ability, self-compaction and segregation resistance of the high flowing concrete.

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A study on the dielectric and electrical conduction properties of$(Sr_{1-x}.Ca_x)TiO_3$ grain boundary layer ceramics ($(Sr_{1-x}.Ca_x)TiO_3$입계층 세라믹의 유전 및 전기전도특성에 관한 연구)

  • 최운식;김충혁;이준웅
    • Electrical & Electronic Materials
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    • v.8 no.5
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    • pp.611-618
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    • 1995
  • The (Sr$_{1-x}$ .Ca$_{x}$)TiO$_{3}$+0.6[mol%]Nb$_{2}$O$_{5}$ (0.05.leq.x.leq.0.2) ceramics were fabricated to form semiconducting ceramics by sintering at about 1350[.deg. C] in a reducing atmosphere(N$_{2}$ gas). Metal oxides, CuO, was painted on the both surface of the specimens to diffuse to the grain boundary. They were annealed at 1100 [.deg. C] for 2 hours. The 2nd phase formed by thermal diffusing from the surface lead to a very high apparent dielectric constant. According to increase of the frequency as a functional of temperature, all specimens used in this study showed the dielectric relaxation, and the relaxation frequency was above 106 [Hz], it move to low frequency with increasing resistivity of grain. The specimens showed three kinds of conduction mechanisms in the temperature range 25-125 [.deg. C] as the current increased: the region I below 200 [V/cm] shows the ohmic conduction. The region rt between 200 [V/cm] and 2000 [V/cm] can be explained by the Poole-Frenkel emission theory, and the region III above 2000 [V/cm] is dominated by the tunneling effect.fect.

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Parent Materials Effect on the Mechanical Property of the Friction Welded Spindle Valve Parts for Marine Engines (선박 엔진용 밸브 스핀들 모재에 따른 마찰 용접 후 기계적 특성 변화)

  • J. W. Shin;J. Y. Park;J. G. Kim
    • Transactions of Materials Processing
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    • v.32 no.3
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    • pp.107-113
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    • 2023
  • The importance of dual-fuel engines has increased for reducing CO2 emissions. However, the low operating temperature of this engine may induce low-temperature corrosion at combustion parts, which reduces the engine service life. To overcome this problem, NiCr38Al4 alloy was developed for valve spindle, but the cost of this alloy is expensive due to its high Cr content. For reducing the manufacturing cost of valve spindle, in the present work, NiCr38Al4 alloy was welded with Nimonic80A alloy by conducting friction welding. The tensile test results show that the strength of friction-welded specimens follows the properties of the lower-strength parent materials, without severe cracks at the interface. The large shear strain and frictional heat from friction welding not only reduce grain size but also induce solute element diffusion at the interfacial region. Because of the low Cr diffusivity compared with Ti, Cr carbides were not observed in the Nimonic80A matrix, while Ti carbides were distributed in both the Nimonic80A and SNCrW matrices.

Temperature History of Mock-up Mass Concrete Considering Different Heat Generation Due to Mixture Adjustment (수화발열량이 다른 콘크리트조합 모의부재 매스콘크리트의 온도이력 특성)

  • Kim Jong;Jeon Chung-Keun;Shin Dong-An;Yoon Gi-Won;Oh Seon-Kyo;Han Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2005.05a
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    • pp.9-12
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    • 2005
  • This paper investigated the temperature history of mass concrete mock up structure considering different heat generation by varying with mixture proportion. Setting time difference between high early strength mixture (E-P) and retarding mixture (R-F30) was 14.5hours. Incorporation of $30\%$ of fly ash contributed to $10^{\circ}C$ of hydration heat reduction. In generally used C and D combination, bottom concrete shows earlier hydration, while E-J combination showed reverse tendency and thus, this method can reduce the crack occurrence. Therefore, heat generation difference method has beneficial effect on reducing crack induced by hydration heat resulting from heat generation difference between surface and center section.

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Parametric Study for Reducing NO and Soot Emissions in a DI Diesel Engine by Using Engine Cycle Simulation (직분식 디젤엔진에서 엔진 매개변수들이 NO 및 soot 배출에 미치는 영향에 대한 수치해석 연구)

  • 함윤영;전광민
    • Transactions of the Korean Society of Automotive Engineers
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    • v.10 no.5
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    • pp.35-44
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    • 2002
  • Engine cycle simulation using a two-zone model was performed to investigate the effect of the engine parameters on NO and soot emissions in a DI diesel engine. The present model was validated against measurements in terms of cylinder pressure, BMEP, NO emission data with a 2902cc turbocharger/intercooler DI diesel engine. Calculations were made for a wide range of the engine parameters, such as injection timing, ignition delay, Intake air pressure, inlet air temperature, compression ratio, EGR. This parametric study indicated that NO and soot emissions were effectively decreased by increasing intake air pressure, decreasing inlet air temperature and increasing compression ratio. By retarding injection timing, increasing ignition delay and applying EGR. NO emission was effectively reduced, but the soot emission was increased.

A Study on the Temperature Dependency Affecting Setting and Strength Development of Concrete Using Mineral Admixtures (혼화재 사용 콘크리트의 응결 및 강도발현에 미치는 온도의존성에 관한 연구)

  • Joo, Eun-Hi;Shon, Myeong-Soo;Jeon, Hyun-Kyu;Han, Min-Cheol;Han, Cheon-Goo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.11a
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    • pp.707-710
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    • 2005
  • This experimental study investigate temperature dependency affecting setting and strength development of concrete using mineral admixtures such as CKD, FA and BS. For the properties of setting at $5^{\circ}C$, setting time of concrete with mineral admixture was delayed about $3\~14$ hour compared with that of plain concrete. Use of CKD had a desirable effect on reducing setting retard under $5^{\circ}C$ because of $CaCO_3$ of CKD while use of FA and BS retarded setting time greatly. For compressive strength under $5^{\circ}C$, concrete with CKD had the most compressive strength in early age compared with the other mineral admixtures but exhibited slight strength loss in $-5^{\circ}C$ at 28days. Especially, concrete with FA and BS was observed in early stage at low curing temperature because of strength loss remarkably in $-5^{\circ}C$.

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Carbon Dioxide Sensor Substrate for Surface-mounted Packaging

  • Han, Hyeuk-Jin;Kim, Tae Wan;Park, Kwang-Min;Park, Chong-Ook
    • Journal of Sensor Science and Technology
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    • v.24 no.3
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    • pp.159-164
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    • 2015
  • Solid state electrochemical and chemo-resistive gas sensors have been used widely but can operate only under high temperature. For reducing the power consumption and optimizing the structure of the substrate of these sensors, we conducted device and circuit simulations using the COMSOL Multiphysics simulator. For assessing the effective types of substrate and heat isolation, we conducted three-dimensional thermal simulations in two separate parts; (a) by changing the shape of the contacting holes and (b) punching additional holes on the substrate. Thus, it was possible to achieve high temperature in the sensor end of the substrate while maintaining low power consumption, and temperature in the circuit.

Studies on the Thermal Stability of Pork Loin Muscle in Previous Heating Temperatures and Holding Times by DSC (DSG를 이용한 예비 가열 온도 및 유지 시간에 따른 돈육 등심 근육의 열안정성에 관한 연구)

  • 김천제;송민석;이창현;이의수;조진국;이찬호;마기준
    • Food Science of Animal Resources
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    • v.18 no.4
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    • pp.358-363
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    • 1998
  • The objectives of this study were to evaluate the effect of previous heating temperature and holding times on the thermal behavior of pork loin muscle by DSC. Pork loin muscles were heated to achieve the following end-point temperatures: 40$^{\circ}C$, 50$^{\circ}C$, 60$^{\circ}C$, 70$^{\circ}C$, 80$^{\circ}C$ at heating rate = 10$^{\circ}C$/min. The first peak was disappeared when samples were initially heated to 50$^{\circ}C$ for 1 minute. As end-point temperature was raised, major peaks were progressively disappeared and peaks were lost completely at 80$^{\circ}C$. Especially, peaks were completely disappeared at 70$^{\circ}C$ for 10 minute. Increasing of exposure time to elevated temperature also increased denaturation, thereby reducing the area of the thermogram.

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