• Title/Summary/Keyword: Dry heat

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철도차량용 금속계 소결마찰재의 조성에 따른 트라이볼로지 특성 (Effects of Composition of Metallic Friction Materials on Tribological Characteristics on Sintered Metallic Brake Pads and Low-Alloy Heat-Resistance Steel for Trains)

  • 양용준;이희성
    • Tribology and Lubricants
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    • 제30권6호
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    • pp.330-336
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    • 2014
  • Sintered metallic brake pads and low alloy heat resistance steel disks are applied to mechanical brake systems in high energy moving machines that are associated with recently developed 200km/h trains. This has led to the speed-up of conventional urban rapid transit. In this study, we use a lab-scale dynamometer to investigate the effects of the composition of friction materials on the tribological characteristics of sintered metallic brake pads and low alloy heat resistance steel under dry sliding conditions. We conduct test under a continuous pressure of 5.5 MPa at various speeds. To determine the optimal composition of friction materials for 200 km/h train, we test and the evaluate frictional characteristics such as friction coefficients, friction stability, wear rate, and the temperature of friction material, which depend on the relative composition of the Cu-Sn and Fe components. The results clearly demonstrate that the average friction coefficient is lower for all speed conditions, when a large quantity of iron power is added. The specimen of 25 wt% iron powder that was added decreased the wear of the friction materials and the roughness of the disc surface. However when 35 wt% iron powder was added, the disc roughness and the wear rate of friction materials increased By increasing the amount of iron powder, the surface roughness, and temperature of the friction materials increased, so the average friction coefficients decreased. An oxidation layer of $Fe_2O_3$ was formed on both friction surfaces.

Comparison of the Impact of an Optimized Ice Cooling Vest and a Paraffin Cooling Vest on Physiological and Perceptual Strain

  • zare, Mansoor;dehghan, Habibollah;yazdanirad, Saeid;khoshakhlagh, Amir hossein
    • Safety and Health at Work
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    • 제10권2호
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    • pp.219-223
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    • 2019
  • Background: Ice cooling vests can cause tissue damage and have no flexibility. Therefore, these two undesirable properties of ice cooling vest were optimized, and the present study was aimed to compare the impact of the optimized ice cooling vest and a commercial paraffin cooling vest on physiological and perceptual strain under controlled conditions. Methods: For optimizing, hydrogel was used to increase the flexibility and a layer of the ethylene vinyl acetate foam was placed into the inside layer of packs to prevent tissue damage. Then, 15 men with an optimized ice cooling vest, with a commercial paraffin cooling vest, and without a cooling vest performed tests including exercise on a treadmill (speed of 2.8 km/hr and slope of %0) under hot ($40^{\circ}C$) and dry (40 %) condition for 60 min. The physiological strain index and skin temperature were measured every 5 and 15 minutes, respectively. The heat strain score index and perceptual strain index were also assessed every 15 minutes. Results: The mean values of the physiological and perceptual indices differed significantly between exercise with and without cooling vests (P < 0.05). However, the difference of the mean values of the indices except the value of the skin temperature during the exercises with the commercial paraffin cooling vest and the optimized ice cooling vest was not significant (P > 0.05). Conclusions: The optimized ice cooling vest was as effective as the commercial paraffin cooling vest to control the thermal strain. However, ice has a greater latent heat and less production cost.

The effect of dietary ions difference on drinking and eating patterns in dairy goats under high ambient temperature

  • Nguyen, Thiet;Chanpongsang, Somchai;Chaiyabutr, Narongsak;Thammacharoen, Sumpun
    • Asian-Australasian Journal of Animal Sciences
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    • 제32권4호
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    • pp.599-606
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    • 2019
  • Objective: The present study was carried out to evaluate the effect of high dietary cation and anion difference (DCAD) rations on diurnal variations in eating and meal patterns, water intake and urination patterns in dairy goats fed under high ambient temperature (HTa). Methods: Ten crossbred dairy goats during peri-parturition period were selected and divided into two groups of five animals each. Experimental diets were control DCAD (control, 22.8 mEq/100 g dry matter [DM]) and high DCAD (DCAD, 39.1 mEq/100 g DM). The composition of two diets consisted of 44% corn silage and 56% concentrate. From the 2nd week to 8th week postpartum, goats were fed ad libitum twice daily either with the control or DCAD total mix ration with free access to water. The spontaneous eating and drinking patterns were determined. Results: The environmental conditions in the present experiment indicated that goats were fed under HTa conditions (average peak THI = 85.2) and were in heat stress. In addition to the typical HTa induced tachypnoea in both groups, the respiratory rate in the DCAD group was significantly higher than the control group (p<0.05). Although the goats from both groups showed comparable level of eating, drinking and urination during experiment, the meal pattern and water intake were different. High DCAD apparently increased eating and meal patterns compared with the control. At week 8 postpartum, goats from high DCAD group had significant (p<0.05) bigger meal size and longer meal duration. Moreover, high DCAD appeared to increase night-time water intake (p<0.05). Conclusion: Both meal pattern and night-time drinking effects of DCAD suggested that feeding with high DCAD ration may alleviate the effect of heat stress in dairy goat fed under HTa conditions.

Changes in milk production and blood metabolism of lactating dairy cows fed Saccharomyces cerevisiae culture fluid under heat stress

  • Lim, Dong-Hyun;Han, Man-Hye;Ki, Kwang-Seok;Kim, Tae-Il;Park, Sung-Min;Kim, Dong-Hyeon;Kim, Younghoon
    • Journal of Animal Science and Technology
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    • 제63권6호
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    • pp.1433-1442
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    • 2021
  • In this study, Saccharomyces cerevisiae culture fluid (SCCF) has been added to a diet of lactating dairy cows to attempt to improve the ruminal fermentation and potentially increase the dry matter intake (DMI) and milk yield. This study was conducted to investigate the effects of SCCF on the milk yield and blood biochemistry in lactating cows during the summer. Twenty-four Holstein dairy cows were randomly assigned to one of four treatments: (1) total mixed ration (TMR-1) (Control); (2) TMR-1 supplemented with SCCF (T1); (3) TMR-2 (containing alfalfa hay) (T2); and (4) TMR-2 supplemented with SCCF (T3). SCCF (5 ml/head, 2.0×107 CFU/mL) was mixed with TMRs daily before feeding to dairy cows. The mean daily temperature-humidity index (THI) during this trial was 76.92 ± 0.51 on average and ranged from 73.04 to 81.19. For particle size distribution, TMR-2 had a lower >19 mm fraction and a higher 8-9 mm fraction than TMR-1 (p < 0.05). The type of TMR did not influence the DMI, body weight (BW), milk yield and composition, or blood metabolites. The milk yield and composition were not affected by the SCCF supplementation, but somatic cell counts were reduced by feeding SCCF (p < 0.05). Feeding SCCF significantly increased the DMI but did not affect the milk yield of dairy cows. The NEFA concentration was slightly decreased compared to that in the control and T2 groups without SCCF. Feeding a yeast culture of S. cerevisiae may improve the feed intake, milk quality and energy balance of dairy cows under heat stress.

저알코올 와인의 가열 및 비가열 살균 후 품질 특성 및 기능성 (Quality Characteristics and Functionality of Low Alcohol Wines after Heat Sterilization and Non-Thermal Sterilization)

  • 신혜림;박혜진;황온빛;최성열;박의광;윤동규;윤향식
    • 한국식품영양학회지
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    • 제35권5호
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    • pp.343-352
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    • 2022
  • Low alcohol (6%) wines were manufactured using Campbell Early. To develop the sterilization process of low alcohol wines, red wines were heat sterilized, and rose wines were nonthermal sterilized by concentration using potassium metasulfite and potassium sorbate. Samples were stored at 25℃ and quality characteristics were investigated by period. Results of this study revealed the pH of the samples after sterilization ranged from 3.15 to 3.19, and the total acidity of wines ranged from 0.011 to 0.024%. The free SO2 contents of wines ranged from 13.00 to 29.678 mg/L, and the total SO2 contents of wines ranged from 47.50 to 121.00 mg/L. L (lightness) of wines decreased whereas a (redness) and b(yellowness) increased. The hue value of wines ranged from 0.52 to 1.03, and decreased significantly(not including rose sweet wines). The color intensity of red and rose dry wines after sterilization increased, whereas red and rose sweet wines decreased. The DPPH radical scavenging activity of red wines and rose wines ranged between 75.50 to 89.23%, and 36.60 to 56.54%, respectively. The total polyphenol contents were 57.51~182.63 mg%. Results of this study provide scientific information to establish the sterilization process of low alcohol wines.

Net energy and its establishment of prediction equations for wheat bran in growing pigs

  • Zhiqian, Lyu;Yifan, Chen;Fenglai, Wang;Ling, Liu;Shuai, Zhang;Changhua, Lai
    • Animal Bioscience
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    • 제36권1호
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    • pp.108-118
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    • 2023
  • Objective: The objective of this experiment was to determine the net energy (NE) value of 6 wheat bran and 1 wheat shorts by indirect calorimetry and establish the NE prediction equations of wheat bran fed to growing barrows. Methods: Forty-eight growing barrows (28.5±2.4 kg body weight) were allotted in a completely randomized design to 8 dietary treatments that included a corn-soybean meal basal diet, 6 wheat bran diets and 1 wheat shorts diet. The inclusion level of wheat bran or wheat shorts in diets is 30%. Results: The addition of wheat bran reduced the apparent total tract digestibility (ATTD) of nutrients (p<0.05). The ATTD of gross energy, crude protein (CP) and dry matter (DM) in the wheat shorts were greater than that in the wheat bran. Addition of wheat bran or wheat shorts had no effect on total heat production and fasting heat production. The NE of wheat bran was negatively correlated with neutral detergent fiber (r = -0.84; p<0.05) and acid detergent fiber (r = -0.83; p<0.05), while it was positively correlated with CP (r = 0.92; p<0.01). The NE values of wheat bran ranged from 6.79 to 8.15 MJ/kg DM, and the NE value of wheat shorts was 12.47 MJ/kg DM. The ratio of NE to metabolizable energy for wheat bran fed to growing pigs was from 66.0% to 71.7%, whereas the value for wheat shorts was 83.7%. Conclusion: The NE values of wheat bran ranged from 6.79 to 8.15 MJ/kg DM, and the NE value of wheat shorts was 12.47 MJ/kg DM. The NE value of wheat bran can be well predicted based on energy content and proximate analysis.

소아 단순 비만의 변증 유형, 변증별 증상, 치법 및 한의치료 분석 - 중의학 논문을 중심으로 - (Analysis of Pattern Identification and Related Symptoms, Treatment Principles and Korean Medicine Treatments on Childhood Simple Obesity -Focused on Traditional Chinese Medicine Literature-)

  • 정윤경;김재현;방미란;이보람;장규태
    • 대한한방소아과학회지
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    • 제37권1호
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    • pp.15-44
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    • 2023
  • Objectives The purpose of this study is to analyze the types of childhood simple obesity and suggest clinical symptoms, treatment principles, and traditional Chinese medicine (TCM) treatments for each type. Methods All kinds of literature published by the China National Knowledge Infrastructure (CNKI) up to August 20, 2022 were analyzed. We extracted information about types of childhood simple obesity, relevant clinical symptoms, treatment principles and TCM treatments. Results 25 studies were included. Spleen deficiency with dampness obstruction, gastrointestinal dampness-heat, internal excess of phlegm-dampness were the most reported. Spleen deficiency with dampness obstruction has symptoms of powerless, heavy limbs, pale tongue, teeth-marked tongue, sunken and slippery pulse. As a treatment, herbal medicine (HM) like modified Banggihwanggitang and acupoint like Joksamri were mainly reported. Gastrointestinal dampness-heat has symptoms of thirst, constipation, edacity, rapid hungering, heavy limbs, red tongue, slippery and rapid pulse. HM like Modified Xiehuangsan to clear heat was mainly reported. Internal excess of phlegm-dampness has symptoms of heavy limbs, lack of strength, tongue with white slimy fur, slippery pulse. Modified Ijintang to dry dampness to resolve phlegm was mainly reported. Conclusions This study analyzed types of pattern, clinical symptoms, treatment principles, and TCM treatments of childhood simple obesity. Based on this study, it is necessary to derive a standardized dialectical information that reflects the domestic situation.

소나무재선충병 피해를 받은 곰솔 원목의 열처리 소요시간 예측 (Prediction of Heat-treatment Time of Black Pine Log Damaged by Pine Wilt Disease)

  • 한연중;서연옥;정성철;엄창득
    • Journal of the Korean Wood Science and Technology
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    • 제44권3호
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    • pp.370-380
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    • 2016
  • 제주도 지역에서 소나무재선충병 피해를 받은 곰솔 원목의 이용확대를 위하여 열처리를 수행하였다. 열처리는 처리 원목의 중심부가 소나무재선충의 사멸온도인 $56^{\circ}C$를 30분간 유지하여야 한다. 곰솔 원목의 초기함수율과 말구지름은 각각 46% ~ 141%, 180 mm ~ 500 mm의 범위이고, 기본비중과 전건비중은 각각 0.47, 0.52이었다. $105^{\circ}C$ 조건에서 함수율과 말구지름에 따라 열처리에 소요되는 시간은 7.7 h ~ 44.2 h의 범위로 측정되었다. 다양한 함수율 및 지름을 갖는 곰솔 원목의 열처리 소요시간을 예측하기 위하여 열처리 진행 중 처리목 내부의 온도분포를 유한차분법을 적용한 2차원 열전달 해석을 통하여 제시하였다. 열전달 해석을 위한 목재의 열적 특성은 함수율에 따른 열전도계수와 비열을 적용하였으며, 자연대류와 강제대류를 합한 형태의 혼합대류에 의한 혼합대류계수를 적용하였다. 실험값과 예측 값의 오차는 3 ~ 45%의 범위로 분석되었다. 곰솔 원목에서 초기함수율이 50%이고, 말구지름이 200 mm, 300 mm, 400 mm인 경우, 예측된 열처리 소요시간은 각각 10.9 h, 18.3 h, 27.0 h이었다. 초기함수율이 75%일 때, 지름에 따라 각각 13.6 h, 22.5 h, 32.8 h이고, 초기함수율이 100%일 때, 지름에 따라 각각 16.2 h, 26.5 h, 38.2 h이었다. 이러한 열처리 소요시간의 예측방법에 소나무와 잣나무 등 다른 소나무재선충병 피해목의 물리적 특성을 적용하면, 함수율과 말구지름에 따른 열처리 소요시간을 제시할 수 있을 것으로 판단된다.

Predicting In Sacco Rumen Degradation Kinetics of Raw and Dry Roasted Faba Beans (Vicia faba) and Lupin Seeds (Lupinus albus) by Laboratory Techniques

  • Yu, P.;Egan, A.R.;Leury, B.J.
    • Asian-Australasian Journal of Animal Sciences
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    • 제13권10호
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    • pp.1377-1387
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    • 2000
  • Two laboratory techniques: (1) an in vitro method with two procedures for measuring protein degradabilities and (2) an in vitro method with three procedures for measuring protein solubility, were investigated to determine which laboratory techniques could most accurately predict the quantity of rumen protein degradation kinetics of legume seeds after dry roasting under various conditions, in terms of (1) rumen protein disappearance ($D_j$, where j=0, 2, 4, 8, 12, 24 and 48 h incubation), (2) rumen protein effective degradability (EDCP), (3) the parameters describing rumen degradation characteristics (the soluble fraction: S, the potentially degradable fraction: D, undegradable fraction: U, lag time: T0 and the degradation rate: Kd) and (4) rumen bypass protein (BCP), which were determined by the method accepted internationally at present, in sacco nylon bag technique using the standardized Dutch method. Feeds evaluated were the raw and dry roasted whole faba (Vicia faba) beans (WFB) and whole lupin (Lupinus albus) seeds (WLS), each was dry roasted under various conditions (at 110, 130 or $150^{\circ}C$ for 15, 30 or 45 min). In vitro protein degradability ($D_1$_Auf and $D_{24}$_Auf) were determined using the modified Aufr re method by enzymatic hydrolysis for 1 h and 24 h using a protease extracted from Streptomyces griseus in a borate-phosphate buffer. In vitro protein solubility ($bf_1$_S, $bf_2$_S, $bf_3$_S) was measured in a borate-phosphate buffer with three different procedures. Results from laboratory techniques (in vitro) were correlated and linearly regressed with in sacco results. Of the three procedures of in vitro protein solubility evaluated, none of them could predict in sacco results with good precision. The highest Pearson correlation coefficient ($R^2$) was less than 0.50. Of two procedures of in vitro protein degradability studied, the $D_1$_Auf values were closely correlated with in sacco parameters: Kd, EDCP and %BCP with high R' values: 0.82, 0.85 and 0.85, respectively, and closely correlated with in sacco $D_j$ at 2, 4, 8 and 12 h rumen incubation with high $R^2$ values: 0.83, 0.91, 0.93 and 0.83, respectively. The $D_{24}$_Auf values could not predict in sacco results. The highest $R^2$ value was less then 0.40. These results indicated that in vitro protein solubility measured in borate-phosphate failed to identify differences in the rate and extent of protein degradation of legume seeds after dry roasting under various conditions and thus should not be used to predict rumen degradation, particularly for heat processed feedstuffs. But in vitro protein degradability using the modified Aufr re method by enzymatic hydrolysis for 1 h or possibly an intermediate time (>1 h and <24 h) is a promising laboratory procedure to detect effectiveness of dry roasting legume seeds on rumen protein degradation characteristics and could be used as a simple laboratory method to predict the rate and extent of protein degradation in the rumen in sacco with high accuracy. The equations to predict EDCP, Kd and BCP of dry roasted legume seeds (WLS and WFB) under various conditions are as follow: For both: EDCP (%)=-1.37+1.06*$D_1$_Auf ($R^2=0.85$, p<0.01). For both: Kd (%/h)=-21.81+0.49*$D_1$_Auf ($R^2=0.82$, p<0.01). For both: %BCP=103.37-1.07*$D_1$_Auf ($R^2=0.85$, p<0.01).

꽃사슴에 있어서 육림부산물 사일리지, 칡 사일리지 및 갈잎건초 급여에 따른 건물채식량, 소화율 및 질소출납의 비교 (Comparison of Dry Matter Intake, Digestibility, and Nitrogen Balance in Spotted Deer (Cervus nippon) fed Forest by-product Silage, Arrowroot (Pueraria thunvegiana) Silage and Oak Browse (Quercus aliena) Hay)

  • 전병태;김언현;이상무;김경훈;문상호
    • Journal of Animal Science and Technology
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    • 제44권1호
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    • pp.87-94
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    • 2002
  • 본 실험은 육림부산물 발효사료의 사슴용 사료가치를 평가하기 위해 꽃사슴에게 육림부산물 사일리지(FBS), 칡 사일리지(ARS) 및 수입 갈잎건초(OLH)를 급여하여 건물채식량, 소화율 및 질소출납을 상호 비교하였다. 건물소화율은 ARS가 가장 높았고 OLH가 가장 낮아 처리구간에 유의성(P$<$0.05)이 인정되었다. 조단백질 소화율의 경우는 OLH구가 FBS와 ARS구에 비해 현저히 낮은(P$<$0.05) 소화율을 나타냈다. 조섬유 소화율의 경우는 FBS가 가장 높고 OLH가 가장 낮았다. 건물채식량은 OLH가 가장 높아 ARS와의 사이에는 유의성(P$<$0.05)이 인정되었으나 FBS와의 사이에는 인정되지 않았다. 그러나 체내에서 이용 가능한 가소화 건물채식량으로 환산했을 경우 차이가 거의 없었다. 체내에 축적된 질소와 섭취질소에 대한 축적질소의 비율은 처리구간에 유의성은 인정되지 않았으나 FBS가 가장 높아 체내 질소의 이용효율이 가장 좋았던 것으로 평가되었다. 결과적으로 육림부산물 사일리지는 다양한 사료자원으로 구성되어 사슴의 기호성이 양호하고 높은 소화율과 건물채식량 및 영양소의 체내 이용성을 나타내고 있어 사슴용 사료로서 충분한 가치를 갖고 있는 사료자원으로 평가되었다.