• Title/Summary/Keyword: cold shortening

Search Result 41, Processing Time 0.02 seconds

Improving the Thermal Environment of Balcony in Apartment House (공동주택 발코니의 열환경 향상방안)

  • Park, Sun-Hyo;Bae, Sang-Hanw;Hong, Cheon-Hwa
    • Proceeding of Spring/Autumn Annual Conference of KHA
    • /
    • 2003.11a
    • /
    • pp.41-46
    • /
    • 2003
  • In recent days, it is usual case to extend the dwelling area to the balcony which is provided by service area. But the use of the extended area can be arisen discomfort with a view point of thermal environment by excessive heat accumulation in summer and excessive cold draft in winter. In this study, the skills were reviewed to improve the thermal environment of the extended area and evaluations were carried out. Additional heat supply by heat-convector installed at the lower end of the curtain wall can improve the thermal environment of the extended area and also arise surface temperature of the curtain wall surface. And aluminum plate installed under the floor could not improve the thermal environment but it was effective to shortening the initial heating time.

  • PDF

Finite Element Analysis of Manufacturing Process of a 12 Point Flange Head Bolt with Emphasis on Thread Rolling Process (나사전조공정을 중시한 12각플랜지볼트의 나사제조공정의 유한요소해석)

  • Jang, S.J.;Lee, M.C.;Shim, S.H.;Son, Y.H.;Yoon, D.J.;Joun, M.S.
    • Transactions of Materials Processing
    • /
    • v.19 no.4
    • /
    • pp.248-252
    • /
    • 2010
  • In this paper, three-dimensional finite element analysis of thread rolling process of a 12 point flange head bolt is conducted using a rigid-plastic finite element method based metal forming simulator AFDEX 3D. A whole sequence of cold forming processes of a long shaft bolt composed of four forging stages and final thread rolling process is simulated to reveal the mechanism of thread formation. A mesh density control function is applied near the major plastic deformation region to achieve computational efficiency. It has been shown both numerically and experimentally that longitudinal lengthening or shortening is negligible in thread rolling.

Evaluation criteria for freezing and thawing of tunnel concrete lining according to theoretical and experimental analysis

  • Moon, Joon-Shik;An, Jai-Wook;Kim, Hong-Kyoon;Lee, Jong-Gun;Lattner, Tim
    • Geomechanics and Engineering
    • /
    • v.29 no.3
    • /
    • pp.349-357
    • /
    • 2022
  • Abnormal climate events are occurring frequently around the world. In particular, cold waves and heavy snow lead to damage and deterioration of facilities, which can cause loss of life or property damage, such as shortening the lifespan of facilities. Therefore, it is very important to prepare an appropriate maintenance system and to establish a strategy to cope with abnormal weather conditions. In this study, laboratory freezing experiments were performed to analyze the freeze-thaw characteristics affecting the tunnel concrete lining, and heat flow analysis was carried out based on the test results. Based on these experimental and theoretical analysis results, quantitative freeze-thaw evaluation criteria for tunnel concrete linings were proposed.

The temperature distributions of the curing space according to blocking the opening of gang-form at the apartment in the cold weather (동절기 공동주택 갱폼 개구부 천막보양에 따른 보양 온도 분포 분석)

  • Cho, Hong-Bum;Song, Jin-Hee;Kim, Young-Sun;Choi, Ji-Su;Lee, Kyu-Nam
    • Proceedings of the Korean Institute of Building Construction Conference
    • /
    • 2022.04a
    • /
    • pp.140-141
    • /
    • 2022
  • CFD analysis was performed to analyze the temperature distribution of the inner space of the curing house according to blocking the opening of the gang-form with a tent in case of concrete pouring and heat curing of the apartment house during the winter season. If the gang-form opening is closed with a tent during internal heating using a hot air blower in the winter, the internal temperature rises compared to the non-reserved due to air-tightness of the curing spaces, and uniform temperature distribution can be ensured. In addition, it is possible to increase curing efficiency by reducing the amount of heat supplied and shortening the heating time.

  • PDF

Studies on the Growth Characters and Nutrient Uptake Related to Source and Sink by Cool Water Temperature at Reproductive Growth Stage I. Influence of Cool Water Irrigation on the Degeneration and Differentiation of Rachis Branches and Spikelets, Sterility Ratio and Ripening Ratio of Rice (생식생장기 냉수온이 벼의 Source와 Sink관련형질 및 양분호흡에 미치는 연구 I. 냉수관개가 지경과 영화의 분화 및 퇴화, 불임, 등숙에 미치는 영향)

  • Choi, Su-Il;La, Jong-Seong;So, Jae-Don;Lee, Man-Sang
    • KOREAN JOURNAL OF CROP SCIENCE
    • /
    • v.30 no.4
    • /
    • pp.359-367
    • /
    • 1985
  • This experiment was conducted to study effect of cold water damage on some growth characters related to source and sink at reproductive growth stage in Jinan (sea level 303m). The cold water irrigation duration had irrigated 4, 8 and 12 days at panicle formation stage and reproduction division stage compared to perennial water irrigation. Cold water irrigation shortened culm length and panicle length and degree of panicle exsertion. The shortening effect appeared great at lower internodes when treated at panicle formation stage but at higher internodes when treated at reduction division stage. Cold water irrigation decreased the number of secondary branches and spikelets per panicle, and increased the number of degenerated spikelets being high degeneration when treated at panicle formation stage. Spikelet sterility and impediment of grain filling were affected by duration of cold water irrigation being great when treated at spikelet primodium differentiation stage and reduction division stage in particular. Grain weight was also reduced. Significant relationship existed between spikelets sterility, grain filling and yield. The degeneration of secondary branches and spikelets correlated with leaf area but spikelet sterility and yield with culm length, panicle length and panicle exsertion.

  • PDF

Biochemical Changes in Brassica Seedlings Due to Uniconazole Treatment (Brassica속 작물 유묘에서 생장억제제 Uniconazole 처리에 따른 생화학적 변화)

  • Park, Woo-Churl;Nam, Min-Hee
    • Applied Biological Chemistry
    • /
    • v.38 no.3
    • /
    • pp.202-206
    • /
    • 1995
  • In order to obtain the basic data for clarifing the mechanism of cold tolerance in crops, we analyzed various biochemical changes according to the Uniconazole treatment in Brassica seedling. Peroxidase activity in the root fraction of Brassica seedling was about 3 to 4 times higher than that in hypocotyl fraction, while catalase activity in those fractions showed opposite trend to the peroxidase activity. The content of hydrogen peroxide in root fraction was higher than that of hypocotyl fraction as being a reciprocal proportion with catalase activity. Especially in all fractions, peroxidase· activity of 'Sandongchae' (B. campestris) seedling, known as cold tolerant, was two-fold higher than that of cold sensitive rape(B. napus). The elongation rate of hypocotyl after germination was faster in B. napus than in B. campestris. The application of Uniconazole at 0.3 to 1.0 ppm to B. napus suppressed 43 to 46% of hypocotyl elongation and increased 65 to 73% of peroxidase activity in hypocotyl fraction. The shortening rate of hypocotyl length due to Uniconazole treatment was positively correlated with the increasing rate of peroxidase activity in hypocotyl fraction. Superoxide dismutase was not induced upon Uniconazole treatment and has only 3 isozymes in any fractions. Its activity was observed in the order of cotyledon>root>hypocotyl fraction.

  • PDF

Temperature Characteristics depending on the Changes of Surface-coated Curing Methods by using some bubble sheets during winter (동절기 버블시트 표면피복 양생방법 변화에 따른 철근의 온도특성)

  • Lee, Jea-Hyeon;Kyung, Yeong-Hyeok;Lee, Sang-Un;Lee, Joung-Gyo;Han, Min-Cheol;Han, Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
    • /
    • 2016.10a
    • /
    • pp.13-14
    • /
    • 2016
  • In the modern construction industry, since numerous skyscrapers have been built, there have been sought for developing various kinds of methods for shortening a construction period. Therefore, many kinds of studies on some kinds of cold-weather concrete have been conducted actively for the purpose of a year-round construction. Accordingly, this research team once developed a double-layered bubble sheet as a surface-coated curing material for winter. And there have been raised some worries that some initial damages to frozen concrete caused by low temperature of reinforcing bars which are exposed out of the wall areas of a wall-type apartment during winter. Therefore, in this study, it is intended to find out clearly whether it is possible for concrete to be damaged initially or not by analyzing the temperature characteristics of the exposed reinforcing bars of the wall areas under the temperature conditions during winter.

  • PDF

A Study of Iron Status and Anemia in Female High School Students in Ulsan (울산시 여고생의 철분영양상태와 빈혈에 관한 연구)

  • 홍순명;황혜진;박상규
    • Korean Journal of Community Nutrition
    • /
    • v.6 no.1
    • /
    • pp.28-35
    • /
    • 2001
  • This study was designed to assess the iron nutritional status and anemia of high school students. 383 female subjects in Ulsan Metropolitan city were evaluated using a questionnaire, and a measurement of hematological indices. The average height and weight of the respondents were 161.24$\pm$4.90 cm and 53.12$\pm$6.37kg, repectively. The average BMI(body mass index) was 20.43$\pm$2.26 which was in the normal ramge. The average hemoglobin(Hb) concentration of the subjects was 13.14$\pm$0.97g/dl, and the average hematocrit(Hct) level was 40.84$\pm$17.40%. Transferrin saturation{TS(%)} was 20.86$\pm$10.32%, and the ferritin by Hct(<36%), 27.2%by TS(<14%),26.6% by ferritin(<12 ng/ml). As for clinical symptoms, the greatest number of respondents reported that they experienced ‘decreased ability to concectrate’. Mean daily intakes of iron were 14.89$\pm$4.48 mg and heme iron intakes were 5.04$\pm$2.13 mg, which was 29.6% of total iron intake. The total iron binding capacity(TIBC) was negatively correlated with Hb concentration(r= -0.222, p<0.01). Serum ferritin was positively correlated with Hb concentration(r= - 0.323, p<0.05) and negatively correlated with TIBC(r= -0.367, p<0.01). TS(%) was positively correlated with Hb concentration(r= 0.402, p<0.01) and positively correlated with serum ferritin(r=0.413, p<0.01). As for the correlation between blood biochemistry and clinical symptoms related to anemia, the Hb concentration was negatively correlated with ‘shortening of breath when going upstairs(p>0.05)’ and ‘cold hands and feet’ significantly(r= -0.109, p<0.05). The level of Mean corpuscular volume(MCV) was negatively correlated with ‘feel dizzy when standing up’,‘tired out easily’, and ‘decrease ability to concentrate’ significantly(p<0.05). In particular, the level of Fe was negatively correlated with ‘shortening of breath when going upstairs’ and ‘feeling blue’ significantly(p<0.01). These results suggest That the prevalence of iron deficiency of female high school students is very high, therefore guidelines for diet supports and nutrition education to improve their iron status should be provided.

  • PDF

Comparative study of productive pattern and educational pattern of tailored-collar (테일러드 칼라의 생산업체용 패턴과 교육용 패턴의 비교연구)

  • Shin, Jang-Hee;Sohn, Hee-Soon
    • Journal of Fashion Business
    • /
    • v.13 no.5
    • /
    • pp.37-44
    • /
    • 2009
  • As the modern society has become highly industrialized and functionalized, the entry of women in public affairs has become brisk and extensive, and the studies of jackets which can satisfy the functions and designs for various activities have become important. Especially in the tailored collar which is the typical collar for female jackets, the studies such as scientific original form design, and design evaluation through analyzing functionality and sensitivity and others must be systematically carried out. In this study, therefore, the objective was placed in examining the actual state of the production of the tailored collar in the field of production first, and inquiring the general theories on the constituent elements of tailored-collar and production methods by analyzing it and comparing it with the educational tailored-collar production methods. First, in regard to the relation between the collar and the length of the backside neck of the bodice, in most cases, they were employing the method to enlarge the length of the backside neck of the bodice by shortening the length of the neck-base girth. That is, they were processing in order that the self collar band inside of the roll line and the fall of the collar can make a soft curved line. Second, when producing tailored-collar patterns, it is desirable to very the inclination according to the breath of the collar or thickness of the fabric because the stability of the inclination of the collar differs depending on the condition the collar is set, the girth of the collar edge. the broader the breath of the collar becomes, the thicker the fabric becomes, and the more the cloth is against the cold, it is necessary to make the inclination larger. Third, in the size relation between the upper collar and under collar, when sewing collars, it becomes thick and stabilized as it goes from the part in which extra pieces were put to the part in which extra pieces are not put. So you must make the upper collar larger by putting in extra pieces. The amount to be put in differs depending on characteristics of the materials.