• 제목/요약/키워드: Mass loss rate

검색결과 398건 처리시간 0.029초

Thermal Characteristics of Living Leaves in Pinus Densiflora with Heat Flux (복사열 증가에 따른 소나무 생엽의 열적특성 분석)

  • Park, Young-Ju;Lee, Hae-Pyeong
    • Journal of the Korean Society of Hazard Mitigation
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    • 제10권5호
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    • pp.75-82
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    • 2010
  • To study the combustion characteristics of forest fuel by fire intensity, the experiment of combustion characteristics on Pinus Densiflora living leaves, which is the weakest species to the forest fire, was delivered, using variables of heat flux(25 kW/$m^2$, 50 kW/$m^2$, 75 kW/$m^2$). With the equipment of Cone calorimeter, the characteristics of ignition, heat, smoke release, CO and $CO_2$ release, and mass loss were analyzed. Pinus Densiflora living leaves containing moisture of 60.66% were not ignited at the heat flux of variables 25 kW/$m^2$, 50 kW/$m^2$, 75 kW/$m^2$. In proportion to the heat flux value, heat release amount and heat release rate reached maximum value rapidly: higher variables came to the maximum by the half rapidity and the maximum value were twice higher than the former lower variables respectively. As for the smoke release, the less heat flux the variable had, the more smoke release it had, due to incomplete combustion. The release amount of CO and $CO_2$ had more maximum value as the heat flux increased and more radiant heat meaned more carbon oxide. When the forest fire breaks out, therefore, a great amount of CO and $CO_2$ will be released by Pinus Densiflora.

A Clinical Study on the Effect of 62 cases through Obesity Clinic in Dae-Gu Hanny University (대구한의대 비만클리닉 내원 환자 62명에 대한 임상적 관찰)

  • Hur, Jin-Il;Kim, Dong-Woo;Park, Kyung;Kim, Dae-Jun;Byun, Joon-Seok;Choi, Bin-Hye
    • The Journal of Internal Korean Medicine
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    • 제27권2호
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    • pp.345-355
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    • 2006
  • Objectives : The purposes of this study are to evaluate the effect of treatment in obesity clinic in Dae-Gu Hanny University and to improve the oriental medical methods of treatment in obesity patients. Methods : 62 patients were classified into four groups by Body Mass Index(BMI) : normal, overweight, 1st obesity and 2nd obesity groups. Weight, BMI, body fat rate and abdominal fat rate were compared in each group by t-test. Results : In distribution of sex, male were 10(16.1%), female were 52(83.9%). Mean age was $31.0{\pm}2.59$ and the patients in twenties and thirties were the most. Mean weight was $71.80{\pm}4.08kg$ and 1st obesity group(23) was the most. Mean BMI was $27.11{\pm}1.20(kg/m^2)$. BMI Changes in obesity groups treated by obesity clinic were $0.95{\pm}0.68kg/m^2$ in normal group, $1.45{\pm}0.38kg/m^2$ in overweight group, $2.67{\pm}0.48kg/m^2$ in 1st obesity group and $4.01{\pm}1.10kg/m^2$ in 2nd obesity group. The changes in all groups were significant. The more the obesity degree was. the more weight loss was. Conclusions : The weight and BMI in patients were almost decreased significantly when they treated. It resulted that the effect of oriental medical treatment in obesity was positive. This study is the effect of treatment in obesity by several medical methods and it is thought that the study of the effects of treatment in obesity by each medical methods that were used in this study is necessary.

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Simulation of Rough Rice Drying by Natural Air(I) (자연공기(自然空氣)에 의한 벼건조(乾燥) 시뮤레이션(I))

  • Chang, D.I.;Chung, D.S.;Pfost, H.B.;Calderwood, D.L.
    • Korean Journal of Agricultural Science
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    • 제10권1호
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    • pp.118-128
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    • 1983
  • Simulation model of natural air grain drying was discussed and modified to predict the changes of grain moisture content and dry matter loss of rough rice drying. The modified simulation model was then validated using actual test data. A series of simulated drying tests using official weather data for 15 years from Beaumont, Texas, was taken to make minimum airflow rate and maximum bed depth of rough rice drying by natural air, under different conditions of initial moisture content of rough rice, airflow rate and harvest date.

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Evaluation of the Burning Properties of Various Carpet Samples by using the Cone Calorimeter and Gas Toxicity Test (콘칼로리미터와 가스유해성 시험법을 이용한 카페트류의 연소특성 평가)

  • Lee, Bong-Woo;Kwon, Seong-Pil;Lee, Jang-Won;Lee, Byoung-Ho;Kim, Hee-Soo;Kim, Hyun-Joong
    • Fire Science and Engineering
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    • 제23권6호
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    • pp.1-9
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    • 2009
  • In this study, the burning behaviours of five different kinds of carpet samples covered with nylon, PP (polypropylene), PTT (poly(trimethylene terephthalate)), wool fabric and NW (nylon and wool) were evaluated by using the cone calorimeter having a radiant flux of 50kW/$m^2$. And the combustion gas toxicity was evaluated according to KS F 2271 test method. As a result of the cone calorimeter test (KS F ISO 5660-1), nylon carpet samples were ignited most easily. In ignition ability or initial flammability, NW carpet samples showed the highest value. In heat release rate (HRR), fire intensity, PP carpet samples were larger than any other samples. Nylon carpet samples were the highest smoke production rate, while N/W carpet samples the lowest. The following were in mass loss rates: NW > wool > nylon > PP > PTT. CO (carbon monoxide) was one of the most toxic gases released from the combustion. PTT carpet samples gave rise to the highest CO concentration, while NW carpet samples the lowest. In addition, PP carpet samples caused the highest $CO_2$ (carbon dioxide) concentration, while NW carpet samples the lowest. Toxicity of the gas produced from carpet samples was determined by the mouse stop motion, and it resulted in the fact that the combustion gas of PTT carpet samples was more toxic than that of any other samples.

Experimental Study on the Thermal Characteristics According to the Content Change of Biodiesel Mixture (바이오디젤 혼합물의 함량변화에 따른 열적 특성에 대한 실험적인 연구)

  • Ju Suk Kim;Jae Sun Ko
    • Journal of the Society of Disaster Information
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    • 제19권3호
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    • pp.532-544
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    • 2023
  • Purpose: To identify and evaluate the risk of chemical fire causative substances by using thermal analysis methods (DSC, TGA) for the hazards and physical property changes that occur when newly used biofuels are mixed with existing fuels It is to use it for identification and evaluation of the cause of fire by securing data related to the method and the hazards of the material according to it. Method: The research method used in this experiment is the differential scanning calorimeter (DSC: Difference in heat flux) through quantitative information on the caloric change from the location, shape, number, and area of peaks. flux) was measured, and the weight change caused by decomposition heat at a specific temperature was continuously measured by performing thermogravimetric analyzer (TGA: Thermo- gravimetric Analyzer). Result: First, in the heat flux graph, the boiling point of the material and the intrinsic characteristic value of the material or the energy required for decomposition can be checked. Second, as the content of biodiesel increased, many peaks were identified. Third, it was confirmed through analysis that substances with low expected boiling points were contained. Conclusion: It was shown that the physical risk of the material can be evaluated by using the risk of biodiesel, which is currently used as a new energy source, through various physical and chemical analysis techniques (DSC + TGA).In addition, it is expected that the comparison of differences between test methods and the accumulation and utilization of know-how on experiments in this study will be helpful in future studies on physical properties of hazardous materials and risk assessment of materials.

Analysis of Nutrient Cycling Structure of a Korean Beef Cattle Farm Combined with Cropping as Affected by Bedding Material Types (깔개물질의 종류에 따른 한우-경종 결합 농가의 양분순환 구조 분석)

  • Lim, Sang-Sun;Kwak, Jin-Hyeob;Park, Hyun-Jung;Lee, Sun-Il;Lee, Dong-Suk;Kim, Yong-Soon;Yun, Bong-Ki;Kim, Sun-Woo;Choi, Woo-Jung
    • Korean Journal of Soil Science and Fertilizer
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    • 제41권5호
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    • pp.354-361
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    • 2008
  • In this study, we analyzed nutrient cycling structure of a small farm (cattle of 100 heads and arable lands of 2.5 ha) in Jeonnam province to investigate the effects of nutrients input by the addition of bedding materials (sawdust and rice hull) and nutrients loss before the application to the soils (the period during manure storage in the feedlot and composting process) on nutrient cycling structure. Sawdust and rice hull added as bedding materials increased N by 1.6% and 14.2% and $P_2O_5$ by 3.1% and 27.4%, respectively, relative to the amount of nutrients produced by excretion. This result suggests that the addition of nutrients via bedding materials should be considered for better estimation of nutrient balance. The most significant characteristics of the nutrient cycling structure was loss of mass and nutrients during the storage (21 days) and composting period (90 days). During this period, 78.4% of N and 9.5% of $P_2O_5$ was lost from sawdust compost; meanwhile, the percentages of loss for rice hull compost were 81.6% and 10.3%, respectively. A lower percentage of nutrients loss in sawdust compost than that in rice hull compost was attributed to the relatively slow decomposition rate of organic materials in the sawdust compost which has higher C/N ratio and lignin contents. Therefore, it was concluded that estimation of nutrient balance should be conducted based on nutrient contents in the final compost being applied to the lands rather than the amount of nutrients contained in the livestock excretion. In addition, the effects of bedding materials on nutrient losses should be also taken into account.

Study on the Change of Nutrients Contents according to the Use of various Multi-Functional Grinder (믹서의 종류에 따른 영양소 함량 변화에 대한 연구)

  • Choi, Byung Bum;Kim, Chun Huem;Kim, Young Soon
    • Culinary science and hospitality research
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    • 제20권6호
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    • pp.262-274
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    • 2014
  • In this study, changes of nutrients such as vitamins, minerals, and antioxidants were determined by using a multi-functional grinder. Contents of vitamin C and vitamin $B_1$ were measured by HPLC, and antioxidant activity was estimated toward free radical scavenging effect in using DPPH. Contents of minerals(Zn, Mn, Fe, Mg, K, and Ca) were computed by ICP-Mass. Results identified that the contents of vitamin C was $44.06{\pm}10.86mg/kg$ in mandarine, $132.1{\pm}22.80mg/kg$ in orange, and $12.79{\pm}2.01mg/kg$ in pineapple by using the hand blender for 3 minutes, and the loss rate of vitamin C contents were 12%, 7%, and 12% in comparison with the control group. In addition, the contents of vitamin C were $41.89{\pm}5.55mg/kg$ in mandarine, $131.51{\pm}12.67mg/kg$ in orange and $16.76{\pm}1.47mg/kg$ in pineapple when using of the grinder for 3 minutes, and the loss rate of vitamin C contents were 16%, 8%, and 17%. The results of vitamin $B_1$ showed a tendency to decrease in the same manner as the content of vitamin C even if there was no significant difference. Furthermore, the result of antioxidant activity revealed that free radical scavenging effect of sample was 60% decreased when using a hand blender and 10% decreased when using a grinder. Thus decrease rate of antioxidant activity when using the hand blender was higher than grinder. Lastly, current study could find any significant differences among the 16 food samples for cooking when employing the multi-functional grinder(p<0.05).

CCD Photometric Observations and Light Curve Synthesis of the Near-Contact Binary XZ Canis Minoris (근접촉쌍성 XZ CMi의 CCD 측광관측과 광도곡선 분석)

  • Kim, Chun-Hwey;Park, Jang-Ho;Lee, Jae-Woo;Jeong, Jang-Hae;Oh, Jun-Young
    • Journal of Astronomy and Space Sciences
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    • 제26권2호
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    • pp.141-156
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    • 2009
  • Through the photometric observations of the near-contact binary, XZ CMi, new BV light curves were secured and seven times of minimum light were determined. An intensive period study with all published timings, including ours, confirms that the period of XZ CMi has varied in a cyclic period variation superposed on a secular period decrease over last 70 years. Assuming the cyclic change of period to occur by a light-time effect due to a third-body, the light-time orbit with a semi-amplitude of 0.0056d, a period of 29y and an eccentricity of 0.71 was calculated. The observed secular period decrease of $-5.26{\times}10^{-11}d/P$ was interpreted as a result of simultaneous occurrence of both a period decrease of $-8.20{\times}10^{-11}d/P$ by angular momentum loss (AML) due to a magnetic braking stellar wind and a period increase of $2.94{\times}10^{-11}d/P$ by a mass transfer from the less massive secondary to the primary components in the system. In this line the decreasing rate of period due to AML is about 3 times larger than the increasing one by a mass transfer in their absolute values. The latter implies a mass transfer of $\dot{M}_s=3.21{\times}10^{-8}M_{\odot}y^{-1}$ from the less massive secondary to the primary. The BV light curves with the latest Wilson-Devinney binary code were analyzed for two separate models of 8200K and 7000K as the photospheric temperature of the primary component. Both models confirm that XZ CMi is truly a near-contact binary with a less massive secondary completely filling Roche lobe and a primary inside the inner Roche lobe and there is a third-light corresponding to about 15-17% of the total system light. However, the third-light source can not be the same as the third-body suggested from the period study. At the present, however, we can not determine which one between two models is better fitted to the observations because of a negligible difference of $\sum(O-C)^2$ between them. The diversity of mass ratios, with which previous investigators were in disagreement, still remains to be one of unsolved problems in XZ CMi system. Spectroscopic observations for a radial velocity curve and high-resolution spectra as well as a high-precision photometry are needed to resolve some of remaining problems.

Changes of Physico-chemical Characteristic on Swine Manure Using Different Suction Strength in Composting System (돈분 퇴비화 시 공기 흡입 강도에 따른 이화학적 특성변화)

  • Lee, Dong-Jun;Kim, Jung Kon;Jeong, Kwang-Hwa;Kawg, Jung-Hoon;Ravindran, B.;Lee, Ji-Woong
    • Journal of the Korea Organic Resources Recycling Association
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    • 제25권2호
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    • pp.59-67
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    • 2017
  • The aim of this experiment was to investigate the effect of air suction rate (SR) during the composting process of swine manure mixed with sawdust used as a bulking agent. In the 25 L composting reactors, the suction rate (SR) was at four different treatment levels (100%, 200%, 300%, 400%), and were fixed on the based on constant aeration rate into the composting mixtures. The temperature reached to thermophilic phase within 2 days and it was maintained up to the $5^{th}$ day of the composting process in all reactors and then gradually decreased to room temperature at the end of the composting process. The moisture content (MC, %) of the initial mixtures was 64.27%, and it was reduced to 38.4, 33.08, 14.59 and 11.93 in the different suction rate of 100%, 200%, 300%, 400%, respectively in the end process. During the composting, the level of pH was increased from 6.83 to 8.67 and it gradually decreased to 7.56 in 100% and 200%(SR). At the same time, the pH values were reduced only up to 8.19 at 300%, and 8.08 at 400%(SR), showing that suction strengths of 100% and 200% were the better option for composting than those of 300% and 400%. The total Kjeldahl nitrogen (TKN) of initial composts mixtures was 2.3% and were changed in 3.3, 3.1, 2.5, and 2.3% at the end of the composting period from the 100%-400% (SR) variations respectively. These results also indicated that 100% and 200% (SR) were more affected by the dry mass loss as $CO_2$ and water evaporation. The initial value of C/N ratio was 25.17 and were significantly reduced to 11.88, 11.97, 14.31, and 14.72 at the end of the experiment, respectively from the 100%-400% (SR) variations. These results suggest that the suction rate (SR) of 100% and 200% relative to constant air supply would be the optimal conditions to produce high-quality compost.

Analysis on Nutrient Intakes and Eating Behaviors of Female Students Visiting Nutrition Counselling Office (체중조절 내담자의 영양섭취 및 식행동 실태 분석)

  • 이보숙;권순형;허채옥;조경련;이영순;김명자;임호남
    • Journal of the East Asian Society of Dietary Life
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    • 제12권5호
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    • pp.352-363
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    • 2002
  • The purpose of this study was to analyze health-related habits, weight control experience and body composition of 344 female students visiting nutrition counselling office. Dietary habits of the subjects were assessed by means of interview with questionnaire and nutrient intakes were evaluated by the simple dietary assessment method. Weight and height were measured to get body mass index(BMI) and waist-hip ratio and their body composition were measured by Inbody 3.0. The obtained results were as follows: 1) Among students, 14.5% were exercising on a regularly basis, of which the exercises were walking and gymnastic exercise(22.1%), jogging(14.1%), and rope-skipping(4.7%), 48.4% of students were little drinking and 30.5% were once a week and smokers were 4.1%. 2) 28.3% of students were little having breakfast and 15.1% were once or twice a week. Two third of total students were not having breakfast regularly. Also only 59.6% of students were having dinner everyday, which means many of them were even skipping dinner. The reasons why they were not having breakfast were because they don't have enough time to eat(66.0%) and for a diet(2.8%) and the reasons for skipping dinner were because they were not hungry(23.0%), for the weight loss(18.2%). It was shown that they would skip dinner rather than breakfast for a weight control. 51.6% of students were taking snack 1~2 times a day and 5.3% were having little snack. 55.4% of students were dining out once a day and 15.4% more am 2 times a day. 3) 46.7% of students were already experiencing weight control before visiting the counselling office. 78.5% of students tried on one kind of weight control method, 11.4% on two kinds, and 10.1 % on more than three kinds. The method they tried for a weight control most was the one food diet using egg, fruits and beans, which is the most popular among them, and the next were an aerobic exercise(23.6%). a diet tried by a famous entertainer (15.5%), and the fasting(14.5%). 4) The average BMI was 21.2 and the body fat rate was 28.1%. As a result of grouping BMI, 12.8% were underweight 67.6% normal weight 11.6% overweight and 8% obesity. Less than standard for the body fat rate were 0.6%, 50.6% standard, 48.5% more than standard. 49.2% of students as normal weight on a BMI were assessed the so-called "skinny obesity. 50% of consulted students situated fat intra-abdominally at the umbilical level(WHR>0.8). 5) The energy intake was 76.6$\pm$17.8% of RDA and constituent ratio of carbohydrate, fat and protein were 64.2$\pm$5.2%, 21.6$\pm$3.7% and 14.3$\pm$2.3%, respectively, which is little over of 20% of recommended ratio of fat. Protein and niacin intake were more than 90% of RDA and riboflavin and vit. C were taken more than 100% of RDA. But Fe intake was 69.4$\pm$19.3%, Ca 76.6$\pm$23.6%, which were the least constituents. There was not remarkable significance between energy intake and nutrient density based on the groups of underweight, normal weight, overweight and obesity of BMI. 6) It was shown that body fat rate had remarkably significant correlation(p<0.000) with BMI(r=0.760) and WHR(r=0.817) respectively, but body fat rate was more correlated with WHR than with BMI. There was not much significant difference between body fat rate and WHR whether they exercised or not. However. BMI was significantly higher in the exercise group because one who showed higher BMI started to exercise since they looked fat in appearance and perceived as they were fat. fat.

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