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고무의 가황(加黃) 및 열전도론(熱傳導論) (3(三))

  • 허동섭;권동용
    • Elastomers and Composites
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    • 제10권2호
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    • pp.136-156
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    • 1975
  • 고무는 불량열전도체(不良熱傳導體)이며 두께가 두꺼우면 내부(內部)가 적정온도수준(適正溫度水準)에 이르기 전까지 가황시간(加黃時間)이 길어진다. 가황온도(加黃溫度)가 상승(上昇)할수록 가황물(加黃物)의 물성(物性)은 열화(劣化)되는 경향(傾向이) 있다. 천연(天然)고무든지 합성(合成)고무든지 간(間)에 과가황(過加黃)에 대(對)한 저항성(抵抗性)이 나쁘므로 특(特)히 고온가황(高溫加黃)에 대(對)해 민감(敏感)하다. 이것은 고온(高溫)에서 단시간(短時間) 가황(加黃)일수록 가속(加速)된다. 평탄가황배합물(平坦加黃配合物)의 경우에서 보더라도 내부(內部)가 적절(適切)히 가황(加黃)되기도 전(前)에 외부(外部)는 과가황(過加黃)이 되는 수가 있다. 근래(近來) 발간(發刊)된 문헌(文獻)에서도 이러한 내용(內容)이 잘 설명(說明)이 되어 있는데 다른 각도(角度)에서 고찰(考察)해 볼것 같으면 정체시간(停滯時間)이 비교적(比較的) 길지 않는 한(限) 가황시간(加黃時間)은 정체시간(停滯時間)과 sheet 가황시간(加黃時間)과의 합(合)이라고 말할 수 있겠다. 예(例)를 들어 설명(說明)하자면 $130^{\circ}C(266^{\circ}F)$에서 정체시간(停滯時間)이 10분(分)이고 sheet 가황시간(加黃時間)이 20분(分)인 제품(製品)은 이 온도(溫度)에서 30분간(分間) 가황(加黃)해야 된다는 것이다. 온도계수(溫度係數)를 2라고 가정(假定)할 경우 $140^{\circ}C(284^{\circ}F)$에서의 가황시간(加黃時間)은 $30\times\frac{1}{2}=15$분(分)이 아니라 $20\times\frac{1}{2}+10=20$분(分)이 된다. 크기가 큰 제품(製品)은 보통(普通) 다음에 있는 여러 방법(方法)들 가운데 한 가지 또는 여러가지를 조합(組合)하여 가황(加黃)시킨다. a) 크기가 작은 것에 대한 것 보다 낮은 온도(溫度)에서 가황(加黃)한다. b) 침투가황-제품(浸透加黃-製品)을 가압하(加壓下)에 두고서 외부가황(外部加黃)은 단속(斷續)시키고 열(熱)이 중심(中心)으로 침투(浸透)하게 한다. c) 단계가황(段階加黃)-처음에는 저온(低溫)에서 시작(始作)하여 일정간격(一定間隔)을 두고 점차(漸次) 온도(溫度)를 상승(上昇)시켜 최종적(最終的)으로 가황온도(加黃溫度)까지 올린다. d) 가능(可能)하다면 metal base나 금형(金型)에서 고무를 증기가황(蒸氣加黃)시킬 경우에 있어서 속이 빈 축(軸)을 사용하여 내부(內部)로 부터 가열(加熱)하면 가황시간(加黃時間)이 단축(短縮)된다. e) 냉각중(冷却中)의 후가황(後加黃)-이것은 가열장치(加熱裝置)에서 끄집어낸 후 제품(製品)의 외부(外部)를 냉각(冷却)시키는 방법(方法)이다. 가열(加熱)된 제품(製品)이 쌓여 있거나 적절(適切)하게 냉각(冷却)되지 않을 때 가황(加黃)이 추가적(追加的)으로 되거나 과가황(過加黃)이 될 우려가 있는 제조공정(製造工程)에서는 흔히들 이 방법(方法)을 무시(無視)하고 있다. 여기서 강조(强調)해 두어야 할 것은 항상 제품(製品)의 외부(外部)를 완전(完全)히 가황(加黃)시킬 필요(必要)는 없다는 것이다. 다공성(多孔性)이나 기포생성(氣泡生成)을 조장(助長)하는 불량가황상태(不良加黃狀態)와 표면(表面)에서의 과가황상태간(過加黃狀態間)의 균형(均衡)을 취(取)해 줘야 하는데 물론(勿論) 이때는 가황시간(加黃時間)을 단축(短縮)시켜야 한다는 경제적(經濟的)인 측면(側面)도 아울러 고려(考慮)해야 한다. 이것은 고무기술자(技術者)가 당면(當面)해야할 과제(課題)에 속(屬)하며 바람직 한것은 본장(本章)의 내용(內容)이 여러 상황하(狀況下)에서 당면(當面)한 문제(問題)에 대(對)해 어떻게 대처(對處)해 야 할지를 모르는 여러 기술자(技術者)들에게 도움이 되었으면 하는 것이다.

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Comparison of Methodologies to Quantify Phytate Phosphorus in Diets Containing Phytase and Excreta from Broilers

  • de P. Naves, L.;Rodrigues, P.B.;Bertechini, A.G.;Correa, A.D.;de Oliveira, D.H.;de Oliveira, E.C.;Duarte, W.F.;da Cunha, M.R.R.
    • Asian-Australasian Journal of Animal Sciences
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    • 제27권7호
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    • pp.1003-1012
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    • 2014
  • The use of a suitable methodology to quantify the phytate phosphorus ($P_{phy}$) content in both the feed and the excreta from broilers is required to enable accurate calculation of the catalytic efficiency of the phytase supplemented in the feed. This study was conducted to compare 2 analytical methodologies (colorimetry and also high-performance liquid chromatography with a refractive index detector) in order to calculate the phytase efficiency by utilizing the results from the methodology that was shown to be the most appropriate. One hundred and twenty broilers were distributed in a $(4+1){\times}2$ factorial arrangement, corresponding to 4 diets that were equally deficient in P supplemented with increasing levels of phytase (0, 750, 1,500, and 2,250 units of phytase activity - FTU - per kg of feed) plus 1 positive control diet without phytase, supplied to male and female birds. The result indicated that the colorimetric methodology with an extraction ratio of 1:20 (mass of sample in g:volume of the solvent extractor in mL) was shown to be the most adequate. There was no interaction between the phytase level and the sex of the broilers (p>0.05). Males consumed 12% more $P_{phy}$ than did females (p<0.01), but the sex of the broilers did not affect (p>0.05) the excretion and retention coefficient of $P_{phy}$. The increase in the phytase level of the diet reduced (linear, p<0.01) the $P_{phy}$ excretion. The greatest $P_{phy}$ retention was estimated at 87.85% when the diet contained 1,950 FTU/kg (p<0.01), indicating that it is possible to reduce the inorganic P in the formulation at an amount equivalent to 87.85% of the $P_{phy}$ content present in the feed, which, in this research, corresponds to a decrease in 2.86 g of P/kg of the feed.

Effects of Dietary Alpha-lipoic Acid and Acetyl-L-carnitine on Growth Performance and Meat Quality in Arbor Acres Broilers

  • Zhang, Yong;Jia, Ru;Ji, Cheng;Ma, Qiugang;Huang, Jin;Yin, Haicheng;Liu, Laiting
    • Asian-Australasian Journal of Animal Sciences
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    • 제27권7호
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    • pp.996-1002
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    • 2014
  • An experiment was conducted to evaluate the effects of dietary alpha-lipoic acid (LA) and acetyl-L-carnitine (ALC) on growth performance, carcass characteristics and meat quality in Arbor Acres broilers. A total of 486 1-d-old male Arbor Acres broilers were randomly allocated to 9 dietary treatments, 9 treatments were group A (0 mg/kg LA and 0 mg/kg ALC), group B (50 mg/kg LA and 0 mg/kg ALC), group C (100 mg/kg LA and 0 mg/kg ALC), group D (0 mg/kg LA and 50 mg/kg ALC), group E (50 mg/kg LA and 50 mg/kg ALC), group F (100 mg/kg LA and 50 mg/kg ALC), group G (0 mg/kg LA and 100 mg/kg ALC), group H (50 mg/kg LA and 100 mg/kg ALC), group I (100 mg/kg LA and 100 mg/kg ALC). Birds were slaughtered at 42 days old. Average daily gain (ADG), average feed intake (AFI), feed conversion rate (FCR), eviscerated rate, breast muscle percentage, thigh muscle percentage, abdominal fat percentage, liver weight, muscle color ($L^*$ value, $a^*$ value, $b^*$ value), pH values at 45 min and 24 h postmortem were measured. Results showed that there existed an interaction between LA and ALC in growth performance of broilers, carcass traits and meat quality. The overall result is that high level of LA and ALC led to lower AFI, ADG (p<0.01), lower abdominal fat percentage, liver weight (p<0.01), lower $L^*$ value, $a^*$ value, and $b^*$ value of breast muscle, $L^*$ value of thigh muscle (p<0.05), and higher FCR (p<0.01), eviscerated rate (p<0.01), breast muscle percentage, thigh muscle percentage (p<0.05), $a^*$ value, pH 45 min and pH 24 h of thigh muscle (p<0.01). These results suggested that dietary LA and ALC contributed to the improvement of meat quality in broilers.

Effect of Cassava Hay and Rice Bran Oil Supplementation on Rumen Fermentation, Milk Yield and Milk Composition in Lactating Dairy Cows

  • Lunsin, R.;Wanapat, Metha;Rowlinson, P.
    • Asian-Australasian Journal of Animal Sciences
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    • 제25권10호
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    • pp.1364-1373
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    • 2012
  • Four crossbred (75% Holstein Friesian) lactating dairy cows, with an average live weight of $418{\pm}5$ kg and $36{\pm}10$ d in milk were randomly assigned according to a $2{\times}2$ factorial arrangement in a $4{\times}4$ Latin square design to evaluate the effects of cassava hay (CH) and rice bran oil (RBO) on feed intake, nutrient digestibility, ruminal fermentation, milk yield, and milk composition. Factor A was non-supplementation or supplementation with CH in the concentrate. Factor B was supplementation with RBO at 0% or 4% in the concentrate mixture. The four dietary treatments were (T1) control (Concentrate with non-CH plus 0% RBO; C), (T2) Concentrate with CH plus 0% RBO (CH), (T3) Concentrate with non-CH plus 4% RBO (RBO), and (T4) Concentrate with CH plus 4% RBO (CHRBO). The cows were offered concentrate, at a ratio of concentrate to milk production of 1:2, and urea-lime treated rice straw was fed ad libitum. Urea-lime treated rice straw involved 2.5 g urea and 2.5 g $Ca(OH)_2$ (purchased as hydrated lime) in 100 ml water, the relevant volume of solution was sprayed onto a 100 g air-dry (91% DM) straw, and then covering the stack with a plastic sheet for a minimum of 10 d before feeding directly to animals. The CH based concentrate resulted in significantly higher roughage intake and total DM intake expressed as a percentage of BW (p<0.05). Ruminal pH, $NH_3$-N, BUN and total VFA did not differ among treatments, while RBO supplementation increased propionate, but decreased acetate concentration (p<0.05). Furthermore, the population of total ruminal bacteria was significantly lower on the RBO diet (p<0.05). In contrast, the total ruminal bacteria and cellulolytic bacteria on the CH diet were higher than on the other treatments. Supplementation with CH increased (p<0.05) F. succinogens and R. flavefaciens populations, whereas the populations of B. fibrisolvens and M. elsdenii were increased on the RBO diet. In addition, supplementation with CH and RBO had no effect on milk production and composition in dairy cows, while fatty acid composition of milk was influenced by RBO supplementation, and resulted in significantly lower (p<0.05) concentrations of both short-chain and medium-chain FA, and increased (p<0.05) the proportion of long-chain FA in milk fat, as well as significantly increased cis-9, trans-11 CLA and total CLA. In conclusion, RBO or CH exhibited specific effects on DMI, rumen fermentation, microbial population, milk yield and composition in lactating dairy cows, which were not interactions between CH and RBO in the diets. Feeding lactating dairy cows with RBO could improve fatty acid in milk fat by increasing cis-9, trans-11 CLA.

A Whole Genome Association Study to Detect Single Nucleotide Polymorphisms for Carcass Traits in Hanwoo Populations

  • Lee, Y.-M.;Han, C.-M.;Li, Yi;Lee, J.-J.;Kim, L.H.;Kim, J.-H.;Kim, D.-I.;Lee, S.-S.;Park, B.-L.;Shin, H.-D.;Kim, K.-S.;Kim, N.-S.;Kim, Jong-Joo
    • Asian-Australasian Journal of Animal Sciences
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    • 제23권4호
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    • pp.417-424
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    • 2010
  • The purpose of this study was to detect significant SNPs for carcass quality traits using DNA chips of high SNP density in Hanwoo populations. Carcass data of two hundred and eighty nine steers sired by 30 Korean proven sires were collected from two regions; the Hanwoo Improvement Center of National Agricultural Cooperative Federation in Seosan, Chungnam province and the commercial farms in Gyeongbuk province. The steers in Seosan were born between spring and fall of 2006 and those in Gyeonbuk between falls of 2004 and 2005. The former steers were slaughtered at approximately 24 months, while the latter steers were fed six months longer before slaughter. Among the 55,074 SNPs in the Illumina bovine 50K chip, a total of 32,756 available SNPs were selected for whole genome association study. After adjusting for the effects of sire, region and slaughter age, phenotypes were regressed on each SNP using a simple linear regression model. For the significance threshold, 0.1% point-wise p value from F distribution was used for each SNP test. Among the significant SNPs for a trait, the best set of SNP markers were selected using a stepwise regression procedure, and inclusion and exclusion of each SNP out of the model was determined at the p<0.001 level. A total of 118 SNPs were detected; 15, 20, 22, 28, 20, and 13 SNPs for final weight before slaughter, carcass weight, backfat thickness, weight index, longissimus dorsi muscle area, and marbling score, respectively. Among the significant SNPs, the best set of 44 SNPs was determined by stepwise regression procedures with 7, 9, 6, 9, 7, and 6 SNPs for the respective traits. Each set of SNPs per trait explained 20-40% of phenotypic variance. The number of detected SNPs per trait was not great in whole genome association tests, suggesting additional phenotype and genotype data are required to get more power to detect the trait-related SNPs with high accuracy for estimation of the SNP effect. These SNP markers could be applied to commercial Hanwoo populations via marker-assisted selection to verify the SNP effects and to improve genetic potentials in successive generations of the Hanwoo populations.

Antibody response to pneumococcal vaccination in children with chronic or recurrent rhinosinusitis

  • Baek, Ji Hyeon;Seo, Hyun Kyong;Jee, Hye Mi;Shin, Youn Ho;Han, Man Yong;Oh, Eun Sang;Lee, Hyun Ju;Kim, Kyung Hyo
    • Clinical and Experimental Pediatrics
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    • 제56권7호
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    • pp.286-290
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    • 2013
  • Purpose: Although chronic and recurrent rhinosinusitis is prevalent in children, little is known about its causes. Here, we investigated the humoral immunity in children with chronic or recurrent rhinosinusitis. Methods: We examined 16 children attending the outpatient clinic at the CHA Bundang Medical Center including 11 boys and 5 girls, aged 3-11 years (mean age, 5.6 years), who had rhinosinusitis for >3 months or >3 times per year. The complete blood count with differential and total serum concentrations of Immunoglobulin (Ig) E, IgA, IgD, IgM, IgG, and IgG subclasses ($IgG_1$, $IgG_2$, $IgG_3$, and $IgG_4$) of all children were measured. All subjects received 23-polysaccharide pneumococcal vaccination (PPV), and the levels of antibodies to 5 serologic types (4, 6B, 14, 18C, and 23F) of pneumococcal capsular polysaccharide antigens were measured before and after vaccination. Post-PPV antibody titers ${\geq}0.35{\mu}g/mL$ or with a ${\geq}4$-fold increase were considered as positive responses. Results: The titers of IgG, IgA, IgD, and IgM were within normal range in all 16 children, whereas the total IgE concentration was higher than normal in 2 children. $IgG_1$ deficiency was observed in 1 patient and $IgG_3$ deficiency in 3. After PPV, 1 patient failed to respond to all 5 serologic types, 2 failed to respond to 4 serologic types, and 2 failed to respond to 3 serologic types. Conclusion: Clinicians should consider the evaluation of humoral immune functions in children with chronic or recurrent rhinosinusitis who do not respond to prolonged antibiotic treatment.

Influence of polymer-coated slow-release urea on total tract apparent digestibility, ruminal fermentation and performance of Nellore steers

  • Gardinal, R.;Calomeni, G.D.;Consolo, N.R.B.;Takiya, C.S.;Freitas, J.E. Jr;Gandra, J.R.;Vendramini, T.H.A.;Souza, H.N.;Renno, F.P.
    • Asian-Australasian Journal of Animal Sciences
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    • 제30권1호
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    • pp.34-41
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    • 2017
  • Objective: Two experiments were performed to evaluate the effects of coated slow-release urea on nutrient digestion, ruminal fermentation, nitrogen utilization, blood glucose and urea concentration (Exp 1), and average daily gain (ADG; Exp 2) of steers. Methods: Exp 1: Eight ruminally fistulated steers [$503{\pm}28.5kg$ body weight (BW)] were distributed into a d $4{\times}4$ Latin square design and assigned to treatments: control (CON), feed grade urea (U2), polymer-coated slow-release urea A (SRA2), and polymer-coated slow-release urea B (SRB2). Dietary urea sources were set at 20 g/kg DM. Exp 2: 84 steers ($350.5{\pm}26.5kg$ initial BW) were distributed to treatments: CON, FGU at 10 or 20 g/kg diet DM (U1 and U2, respectively), coated SRA2 at 10 or 20 g/kg diet DM (SRA1 and SRA2, respectively), and coated SRB at 10 or 20 g/kg diet DM (SRB1 and SRB2, respectively). Results: Exp 1: Urea treatments (U2+SRA2+SRB2) decreased (7.4%, p = 0.03) the DM intake and increased (11.4%, p<0.01) crude protein digestibility. Coated slow-release urea (SRA2+-SRB2) showed similar nutrient digestibility compwared to feed grade urea (FGU). However, steers fed SRB2 had higher (p = 0.02) DM digestibility compared to those fed SRA2. Urea sources did not affect ruminal fermentation when compared to CON. Although, coated slow-release urea showed lower (p = 0.01) concentration of $NH_3-N$ (-10.4%) and acetate to propionate ratio than U2. Coated slow-release urea showed lower (p = 0.02) urinary N and blood urea concentration compared to FGU. Exp 2: Urea sources decreased (p = 0.01) the ADG in relation to CON. Animals fed urea sources at 10 g/kg DM showed higher (12.33%, p = 0.01) ADG compared to those fed urea at 20 g/kg DM. Conclusion: Feeding urea decreased the nutrient intake without largely affected the nutrient digestibility. In addition, polymer-coated slow-release urea sources decreased ruminal ammonia concentration and increased ruminal propionate production. Urea at 20 g/kg DM, regardless of source, decreased ADG compared both to CON and diets with urea at 10 g/kg DM.

Feasibility & Limitations of Endovascular Coil Embolization of Anterior Communicating Artery Aneurysms

  • Hwang, Sung-Kyun;Benitez, Ronald;Veznedaroglu, Erol;Rosenwasser, Robert H.
    • Journal of Korean Neurosurgical Society
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    • 제38권2호
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    • pp.89-95
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    • 2005
  • Objective : The purpose of this study is to analyze aneurysm morphology and define limitations and feasibility in endovascular Gugliemi detachable coil[GDC] embolization for anterior communicating artery [ACoA] aneurysms. Methods : From January 2000 through October 2003, 123patients were treated with endovascular coil embolization for ACoA aneurysms. There were 75women and 48men, with a mean age of 63years. All ruptured aneurysms were treated within 15days of rupture. Aneurysm morphology was classified according to neck size and projection of aneurysm dome as follows-A : neck of aneurysm <4mm & anterior projection, B : neck of aneurysm [4mm & anterior projection, C : neck of aneurysm<4mm & posterior [superior] projection, D : neck of aneurysm [4mm & posterior [superior] projection, E : neck of aneurysm<4mm & inferior projection, and F : neck of aneurysm [4mm & inferior projection. Endovascular procedures were categorized as either "successful" or "unsuccessful". Clinical follow-up was estimated at discharge and at 6months, post treatment results were classified according to Glasgow Outcome Scale[GOS]. Results : Successful embolization for ACoA was performed in 86patients of 123patients [69.9%]. Complete or near complete aneurysm occlusion was observed in 102patients [82.9%]; a neck remnant was observed in 6patients [4.9%]; partial embolization was done in 3patients [2.4%]; and embolization was attempted in 12patients [9.8%]. Among 55patients with follow-up angiographic results, 18patients [32.7%] were defined as recanalization of the aneurysm sac. Morphological analysis demonstrated that anterior projecting aneurysms and morphological classifications [morphological classifications worsens [A - D] chances of successful coil occlusion significantly decrease] were major factors in successful embolization, and, inferiorly projecting and wide neck [${\ge}4mm$] aneurysms are highly related to recanalization of aneurysms. Conclusion : Endovascular coil embolization of ACoA aneurysms shows good outcome in our study. Nevertheless, there is a limitation in the endovascular approach to ACoA, even though advanced modern techniques evolve rapidly. Compensatory surgical approach with the endovascular approach is required for successful treatment of ACoA aneurysms.

산업부산물을 활용한 고강도 경량콘크리트 보의 전단강도에 대한실험 연구 (Experimental Studies on Shear Strength of High-Strength Lightweight Concrete Beam using the Industrial by-products)

  • 이승조;박정민;김화중
    • 콘크리트학회논문집
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    • 제18권5호
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    • pp.621-630
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    • 2006
  • 산업부산물을 활용한 고강도 경량 콘크리트 보의 역학적 거동 구명과 함께 경량 콘크리트 보의 이론식을 바탕으로 합리적인 전단강도식을 제안하였다. 보는 경량 골재를 사용한 고강도 경량 콘크리트 보(L) 8개와 일반 골재를 사용한 고강도콘크리트 보(H) 4개의 실험체를 제작하였다. 그리고 전단스팬비(a/b=1.5, 2.5, 3.5, 4.5), 인장철근비(${\rho}$=0.57, 1.0, 1.59, 2.3%), 콘크리트의 압축강도(35.4, 65.3MPa)를 주요 변수로 설정하여 실험하였다. 이로부터 보에 대한 하중-처짐관계 및 변형률 분포, 파괴성상, 최대내력 등에 대하여 측정하였다. 또한 보의 전단강도식의 제안을 위하여 사인장 균열 강도와 극한전단강도로 세분화하여 기존 제안식과 규준식에 적용시켜 상호 비교 분석을 하였다. $V_{cr}$에 있어서는 a/b=2.5 이상에서는 ACI 규준식과 Zsutty제안식에서 감소하는 결과였지만, Mathey의 제안식에서는 약간의 상승 경향을 보였다. 또한, ${\rho},\;f_c$의 증가에 따라 $V_{cr,\exp}/V_{cr,cal}$은 과대평가의 경향이 나타났다. 한편, $V_{u, \exp}/V_{u,cal}$에서는 통계적인 방법으로 유도된 Zsutty의 제안식이 실험결과와의 일치성에서 좋은 결과를 보였다. 이 식으로부터 유도 수정된 전단강도에 대한 제안식은 $V_{cr},\;V_u$에서 합리적으로 예측할 수 있음을 알 수 있었다. 따라서 본 연구에서 제안된 전단강도 식은 경량 콘크리트의 전단스팬비, 인장철근비, 콘크리트 압축강도의 변화에 따른 전단내력을 합리적으로 평가하는데 유용하게 활용될 수 있을 것으로 사료된다.

콘크리트의 피로균열 성장거동에 관한 연구 (The Fatigue Crack Growth Behavior of Concrete)

  • 김진근;김윤용
    • 콘크리트학회지
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    • 제9권3호
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    • pp.127-135
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    • 1997
  • 본 연구에서는 콘크리트의 피로균열 성장거동을 구명하기 위하여 쐐기쪼갬실험( WST)을 수행하였다. 연구의 주안점인 피로균열 성장거동의 주요영향인자는 콘크리트의 강도로서 28,60,118 MPa 등 3가지의 강도를 변수로 택하였다. 한편, 응력비를 6,13%의 2가지로 변화시켜 그 영향을 관찰하였다. 소정의 응력비을 주기 위하여 최고피로하중수준을 75~85%, 최저응력수준을 5~10%로 각각 유지하였다. 피로실험전에 균열개구변위( CMOD)컴플라이언스 보정 실험을 수행한 후, 그 결과인 균열길이와 컴플라이언스의 관계를 피로실험 중에 균열길이를 예측하는데에 이용하였다. 또한 CMOD컴플라이언스 보정법의 타당성을 검증하기 위하여 선형탄성 파괴역학( LEFM) 및 염색법에 의하여 예측된 균열길이와 비교하였다. 실험결과에 의하여 선형탄성 파괴역학에 근거한 피로균열 성장속도 모델(da/dN- K1 관계)을 제시하였고 콘크리트의 강도가 증가함에 따라 피로균열의 성장속도가 빨라지는 것으로 평가되었다. 또한 응력비가 피로균열 성장속도에 영향을 미치는 것으로 나타났는데 강도가 증가함에 따라 그 정도가 감소하는 경향을 보였다. LEFM 과 염색법 의하여 예측된 균열길이와 비교하여 본 결과 CMOD컴플라이언스 보정법이 쐐기쪼갬실험(WST)에 적용될 수 있음이 검증되었다.