• Title/Summary/Keyword: Water Absorption Test

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The Effects of Steel-Fiber Reinforcement on High Strength Concrete Replaced with Recycled Coarse Aggregates More Than 60% (순환굵은골재 60% 이상 사용한 고강도 콘크리트에 대한 강섬유 보강 효과)

  • Kim, Yoon-Il
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.4 no.4
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    • pp.404-417
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    • 2016
  • The purpose of this study is to examine the extent to which the deterioration in strength of high strength concrete of 60MPa replaced by a large amount of recycled coarse aggregates (more than 60% to 100% of replacement ratio) could be recovered with steel fiber reinforcement through material compressive strength test and shear failure test on short and middle beams and then to offer useful data for aggregate supply system of a sustainable resource circulation type. This study first examined the results of previous related tests. The results of the material compressive strength tests confirmed that when using a combination of steel fiber reinforcements of volumn ratio 0.75% and high quality recycled coarse aggregates with an water absorption rate within 2.0%, the strength characteristics of high strength concrete of 60MPa level were not only restored to the strength level of concrete made with natural aggregates, but also showed superior ductility. And the shear failure tests on short and middle beams using recycled coarse aggregates more than 60% with shear span to depth ratio (a/d) of 2 and 4 controlled by shear forces mainly confirmed that effects of superior shear strength increase and ductile behavior characteristics were showed by steel fiber reinforcements.

Preparation of Noodle with Laver Powder and its Characteristics (김분말을 이용한 국수의 제조 및 특성)

  • Lee, Jang-Wook;Kee, Hae-Jin;Park, Yang-Kyun;Rhim, Jong-Whan;Jung, Soon-Teck;Ham, Kyung-Sik;Kim, In-Chul;Kang, Seong-Gook
    • Korean Journal of Food Science and Technology
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    • v.32 no.2
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    • pp.298-305
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    • 2000
  • Laver noodles were prepared with composite flour containing various ratios of laver powder sifted through 100-mesh sieve and their cooking characteristics were evaluated. Farinograph test results with the composite flour showed that water absorption rate increased linearly as the content of laver powder increased from 2% to 8%, while dough stability decreased linearly with the laver content. Dough development time increased 2.65-3.75 times by adding laver powder. DSC endotherms indicated that onset temperature $(T_o)$, peak temperature $(T_p)$, and conclusion tempearture $(T_c)$ of composite flour starch gelatinization shifted to a higher temperatures as the laver powder content increased. Difference in laver species (e.g., Porphyra dentata and Porphyra tenera) did not affect dough characteristics and surface color of doughs and noodles made with composite flours. From the sensory evaluation test for noodles, a laver noodle containing 4% roasted Porphyra dentata was the most preferred among the noodles tested.

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Mechanical Properties of Granulated Ground Blast Furnace Slag on Blended Activator of Sulfate and Alkali (황산염 및 알칼리계의 혼합 활성화제에 대한 고로슬래그미분말의 역학적 특성)

  • Kim, Tae-Wan;Jun, Yu-Bin;Eom, Jang-Sub
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.19 no.5
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    • pp.104-111
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    • 2015
  • This study shows the mechanical properties of alkali-activated slag cement (AASC) synthesized using sulfate with NaOH solution. The used sulfates were calcium sulfate ($CaSO_4$, denoted CS) and sodium sulfate ($Na_2SO_4$, denoted SS). The replacement ratio of sulfates was 2.5, 5.0, 7.5 and 10.0% by weight of slag. NaOH solution of 2M and 4M concentration was used. A sample was activated with sulfate and activated with blended activator (blending NaOH solution with sulfate) respectively. 24 mix ratios were used and the water-binder weight ratio for the test was set 0.5. This research carried out the compressive strength, flexural strength, ultrasonic pulse velocity (UPV), absorption and X-ray diffraction (XRD). In the case of samples with CS, sample with 7.5% CS, sample with 2M NaOH+5.0% CS and sample with 4M NaOH+5.0% CS showed the good performance in the strength development. In the case of samples with SS, sample with 10.0% SS, sample with 2M NaOH+7.5% SS and sample with 4M NaOH+2.5% SS obtained good performance in strength. The results of UPV and water absorption showed a similar tendency to the strength properties. The XRD analysis of samples indicated that the hydration products formed in samples were ettringite, CSH and silicate phases. In this study, it is indicated that when compared to the use of sulfate only, the use of both sulfate and NaOH solution makes mechanical properties of AASC better.

Effects of Gibberellic Acid and Abscisic Acid on Proteolysis of Senescing Leaves from Rice Seedlings (노화 수도유묘엽의 단백질분해에 미치는 GA$_3$과 ABA의 영향)

  • Kang, S. M;Kang, N. J;Cho, J. L;Kim, Z. H;Kwon, Y. W
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.38 no.4
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    • pp.350-359
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    • 1993
  • The effect of gibberellic acid ($GA_3) and abscisic acid (ABA) on KCl-enhanced proteolysis of senescing leaves of rice(Oryza sativa L. cv. Chilsung) was studied. Emphasis was given to their effects on KCI-enhanced efflux of amino acids and proteinase activity. When treated singly, $GA_3 affected leaf proteolysis little, while ABA increased proteolysis, the rate of amino acid efflux, and ribulose -1,5 -bisphosphate carboxylase / oxygenase (Rubisco)-degrading endoproteinase activity. An additive increase in all three parameters mentioned above was observed when leaves were treated with ABA and KCl. No such an additive effect was found when $GA_3 was treated with KCl. Both $GA_3 and ABA helped to alleviate the KCI-suppressed activity of Rubisco-degrading exoproteinases. The additive increase in proteolysis of rice leaves in the presence of both ABA and KCl could thus be ascribed to a further increase in the efflux of protein hydrolyzates and Rubisco-degrading endoproteinase activity. An increase in proteolysis was accompanied by a decrease in water absorption, and the combined treatment of ABA with KCl resulted in a further reduction of water absorption.

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Sensory and Physical Characteristics of Hwajeun Depended on the Various Levels of Oil Amounts and frying Time (기름의 양과 지지는 시간에 따른 화전의 관능적 및 물리적 특성)

  • 이승현;박정은;장명숙
    • Korean journal of food and cookery science
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    • v.19 no.6
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    • pp.765-771
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    • 2003
  • The aim of this study was to standardize the various methods and recipes of Hwajeun (glutinous rice pancake with flower) appeared in the literature. For this purpose, the effects on the sensory and rheological characteristics of Hwajeun in terms of the various levels of oil and frying times were investigated. This experiment consisted of a sensory evaluation in terms of the acceptance (color, flavor, oily feeling, softness, chewiness, adhesiveness, taste and overall preference) and objective evaluation performed by a texture analyzer, a color difference meter and measurements of the water content and oil absorption. The moisture content of the treatments as a function of the frying time, S7, showed a significantly(p<0.01) low value, and the oil absorption of the Hwajeun made with different frying times increased in proportion to the increment of the frying time(p<0.001). In terms of color, the b value of the Hwajeun made with 16g oil for frying showed a higher value than the others. In the two bite compression test, the hardness of the Hwajeun made with 4g oil for frying showed a significantly (p<0.001) high value among the S2 and S3 samples. As a result of the sensory evaluation for the Hwajeun made with various amounts of oil and frying times, the Hwajeun made with 16g oil for frying and a 2 min frying time for each side (S6) was the most preferred in terms of the softness, chewiness, taste and overall preference of the sensory evaluation

Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2013 (설비공학 분야의 최근 연구 동향 : 2013년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.26 no.12
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    • pp.605-619
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    • 2014
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2013. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of fluid machinery, pipes and relative parts including orifices, dampers and ducts, fuel cells and power plants, cooling and air-conditioning, heat and mass transfer, two phase flow, and the flow around buildings and structures. Research issues dealing with home appliances, flows around buildings, nuclear power plant, and manufacturing processes are newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for general analytical model for desiccant wheels, the effects of water absorption on the thermal conductivity of insulation materials, thermal properties of Octadecane/xGnP shape-stabilized phase change materials and $CO_2$ and $CO_2$-Hydrate mixture, effect of ground source heat pump system, the heat flux meter location for the performance test of a refrigerator vacuum insulation panel, a parallel flow evaporator for a heat pump dryer, the condensation risk assessment of vacuum multi-layer glass and triple glass, optimization of a forced convection type PCM refrigeration module, surface temperature sensor using fluorescent nanoporous thin film. In the area of pool boiling and condensing heat transfer, researches on ammonia inside horizontal smooth small tube, R1234yf on various enhanced surfaces, HFC32/HFC152a on a plain surface, spray cooling up to critical heat flux on a low-fin enhanced surface were actively carried out. In the area of industrial heat exchangers, researches on a fin tube type adsorber, the mass-transfer kinetics of a fin-tube-type adsorption bed, fin-and-tube heat exchangers having sine wave fins and oval tubes, louvered fin heat exchanger were performed. (3) In the field of refrigeration, studies are categorized into three groups namely refrigeration cycle, refrigerant and modeling and control. In the category of refrigeration cycle, studies were focused on the enhancement or optimization of experimental or commercial systems including a R410a VRF(Various Refrigerant Flow) heat pump, a R134a 2-stage screw heat pump and a R134a double-heat source automotive air-conditioner system. In the category of refrigerant, studies were carried out for the application of alternative refrigerants or refrigeration technologies including $CO_2$ water heaters, a R1234yf automotive air-conditioner, a R436b water cooler and a thermoelectric refrigerator. In the category of modeling and control, theoretical and experimental studies were carried out to predict the performance of various thermal and control systems including the long-term energy analysis of a geo-thermal heat pump system coupled to cast-in-place energy piles, the dynamic simulation of a water heater-coupled hybrid heat pump and the numerical simulation of an integral optimum regulating controller for a system heat pump. (4) In building mechanical system research fields, twenty one studies were conducted to achieve effective design of the mechanical systems, and also to maximize the energy efficiency of buildings. The topics of the studies included heating and cooling, HVAC system, ventilation, and renewable energies in the buildings. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment is mostly focused on indoor environment and building energy. The main researches of indoor environment are related to infiltration, ventilation, leak flow and airtightness performance in residential building. The subjects of building energy are worked on energy saving, operation method and optimum operation of building energy systems. The remained studies are related to the special facility such as cleanroom, internet data center and biosafety laboratory. water supply and drain system, defining standard input variables of BIM (Building Information Modeling) for facility management system, estimating capability and providing operation guidelines of subway station as shelter for refuge and evaluation of pollutant emissions from furniture-like products.

The Chemical Properties and Fertilizer Effect of a Residual By-product of Glutamic Acid Fermentation -I. Chemical properties and effect on the growth of corn (구르타민 산발효잔사가공물(酸醱酵殘渣加工物)의 성질(性質)과 비효 -I. 그 성질(性質)과 옥수수에 대(對)한 비효)

  • Hong, Chong Woon;Jung, Yee Geun;Park, Chon Suh;Kim, Yung Sup
    • Korean Journal of Soil Science and Fertilizer
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    • v.6 no.3
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    • pp.159-163
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    • 1973
  • A by-product from glutamic acid fermentation prepared by treating the fermentation residue with sulfuric acid and ammonium hydroxide was studied in the light of its chemical properties by chemical analysis and X-ray diffraction technique. Its effectiveness as fertilizer was also investigated with corn as test plant. The results are summarized as following. 1. The chemical analyses and study with X-ray diffraction technique revealed that the by-product contains an appreciable quantity of water soluble ammonium as ammonium sulfate and ammonium chloride, water soluble amino acid and in-soluble organic carbon. Particularly, the X-diffraction pattern of the material indicated the presence of unidentified water soluble double salt of ammonium sulfate and ammonium chloride. 2. The water soluble ammonium in this material was found to be as effective as urea on the growth of corn plant. 3. The organic portion of the material was found to be equally effective on the growth of corn plant as the other sources of organic matter such as compost and rice bran. It was, however found that the organic matter in the fermentation residue is more persisting in the soil than the compost and rice bran. 4. It was noticed that the application of the fermentation by-product, lowers the soil pH significantly. Inspite of the pH lowering effect, the absorption of iron by corn plant was surpressed by the application of this material.

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Effect of Chemical Treatments on Seed Germination of Saururus chinensis (Lour.) Baill., an Endangered Species in Korea (멸종위기 야생식물 삼백초의 종자발아에 미치는 화학적 처리의 영향)

  • Cho, Ju Sung;Lee, Cheol Hee
    • Korean Journal of Plant Resources
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    • v.29 no.4
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    • pp.385-392
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    • 2016
  • This research was performed to develop seminal propagation method of Saururus chinensis (Lour.) Baill. by conducting a rigorous germination study. Well-selected seeds were dry-stored at 4 ± 1.0℃ during the experiment. To study dormancy type, non-stored seeds were analyzed by embryo observation, germination test and detecting for any difficulties in seed coat to absorb moisture. Then to improve germination, seeds were submerged for 24 hours in a solution of varying concentrations containing one of plant growth regulators and minerals. According to research, fleshly matured seeds had an undifferentiated embryo and had a low germination rate below 5%. In addition, water submersion led to moisture absorption, embryo in the seeds grew and germinated so it was deemed morphophysiological dormant seeds. Percent germination (PG) and germination energy (GE) was greatly improved by soaking in plant growth regulators and minerals for 24 hours. Especially, 500 ㎎/L GA3 treatment resulted in the highest GE as 46.1%. KNO3 meaningfully improved PG (54.3∼57.7%) at 10∼20 mM but effect of minerals on germination acceleration as GE were negatively impacted in all concentrations.

Dough Characteristics of Korean Wheat Flour (국산 밀가루의 반죽특성)

  • 정헌상;박남규;송정춘;김기종;정만재
    • Food Science and Preservation
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    • v.6 no.2
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    • pp.161-166
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    • 1999
  • In order to increase the Korean wheat-cultivators' incomes as well as to promote their consumptions, the native wheat of 11 varities (Chokwangmil, Geurumil, Eunpamil, Tapdongmil, Woorimil, Olgeurumil, Alchanmil , Gobunmil, Geungangmil Seodunmil and Suwon 265) were investigated on dough properties to compared with those of two imported wheat varieties, DNS (Dark Northern Spring Wheat) and ASW (Austrlian Standard White). In dough stickiness, Chokwangmil was highest as 81.78, and the mean value of native wheat was 53.98 g. ASW and DNS showed the stickiness values of 58.7 g and 52.9 g, respectively. Tapdongmil was highest in the tensile tone of dough as 87.6 g. In the texture test, the highest elasticity, gumminess, firmness and chewiness were observed in Woorimil as values of 0.980, 1,022.8, 1,562.7 and 1,001.9, respectively, while the highest cohesiveness and adhesiveness were obtained from Suwon 265 and Geurumil, respectively, as 0.710 and -609.4. In amylogram properties, the initial gelatinization temperature was ranged from 65$^{\circ}C$ to 69$^{\circ}C$, and maximum, minimum and final viscosities were highest in Woorimil as 1,140, 1,100 and 1,730 BU, respectively. In farinogram, water absorption rate was highest in Suwon 265 as 65.1%, which required the longest dough arrival time of 3.5 min. Dough developing time, weakening and stability were longest in Gobunmil as 9.7. 32.1 and 29.9 min., respectively. The resistance of dough was highest in Olgeurumil as 110 BU.

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Watertightness and Durability Properties of Ultra Rapid Hardening Grout using Bottom-ash (잔골재 대체재로서 바텀애쉬를 이용한 초속경 그라우트재의 수밀성 및 내구특성)

  • Lee, Gun-Cheol;Oh, Dong-Uk;Cho, Byoung-Young;Kim, Young-Geun;Cho, Chung-Ki
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.6 no.3
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    • pp.102-109
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    • 2011
  • In this study, in order to develop ultra rapid hardening mortar(URHM) for tunnel repairs using bottom ash of low recycle ratio and Admixture as Eco concept, watertightness and durability properties of URHM on temperature condition of construction field were performed. Test result, seepage quantity and water absorption coefficient regarding watertightness of URHM were as in the following : series II > series I. Seepage quantity for the standard condition were smaller than low temperatures. all specimens were satisfied below 20g as standards of seepage quantity on KS F 4042. Because of the decrease of unit cement content by to replacement of blast furnace slag, the neutrlization resistance for durability properties was reduced. The result of alkali resistance and acide resistance, compressive strengths for specimens soaked in calcium hydroxide solution of seriesI were lower than compressive strengths for specimens not soaked. On the other hand, the case of series II show that the deterioration of compressive strengths for specimens was not almost showed. Compressive strengths of specimens soaked were similar with specimens not soaked except series II-C in $5^{\circ}C$. Therefore, specimens using both blast furnace slag and bottom ash were good in alkali resistance and acide resistance.

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