• Title/Summary/Keyword: Rapid Mixing

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The rapid synthesis of $MoSi_2$ for high-temperature furnace heating elements

  • Soh, Dea-Wha;Natalya, Korobova
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11b
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    • pp.38-41
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    • 2001
  • The combustion characteristics of the disilicides molybdenum system have been studied experimentally. The pertinent reaction parameters that control self-propagating high temperature synthesis reactions have been examined. These include reactant particle size, powder mixing and compaction, reaction stoichiometry, diluents. The influence of experimental variables on integrity, uniformity, structure, and related material properties will be discussed. Formation mechanism of $MoSi_2$ during SHS might be different and depending on experimental conditions.

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The rapid synthesis of MoSi$_2$ for high-temperature furnace heating elements

  • Soh, Deawha;Korobova, Natalya
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.11a
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    • pp.38-41
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    • 2001
  • The combustion characteristics of the disilicides molybdenum system have been studied experimentally. The pertinent reaction parameters that control self-propagating high temperature synthesis reactions have been examined. These include reactant particle size, powder mixing and compaction, reaction stoichiometry, diluents. The inf1uence of experimental variables on integrity, uniformity, structure, and related material properties will be discussed. Formation mechanism of MoSi$_2$ during SHS might be different and depending on experimental conditions.

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Evaluation of Physical Properties according to Mixing Ratio and the Survey of the Current Situation for Epoxy Resin used in Conservation (문화재 보존처리에 사용되는 에폭시수지의 사용현황과 배합비율에 따른 물성 변화 연구)

  • Lee, Eun Ji;Jang, Sung Yoon
    • Journal of Conservation Science
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    • v.32 no.2
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    • pp.223-234
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    • 2016
  • Two-component epoxy resin is widely used in the cultural heritage restoration field. However according to mixing ratio of resin and hardener, curing property, mechanical strength and chemical structure differ which have possibility to effect the stability of cultural heritage. Result of questionnaire survey shows hands-on workers in the conservation field tend to mix the epoxy resin with his or her eye measurement when the using amount is small or mix additional hardener to shorten the pot life of epoxy resin. This research aims to analyze the curing property, mechanical strength and chemical structure of rapid curing type epoxy resin and medium curing type one depending on relative ratio of 0.25~4 of hardener to resin. When the amount of hardener was 0.5~2 times more than the resin, exothermic heat and curing speed were both increased. In case of included hardener to resin was lower than official ratio, mechanical strength (tensile shear strength, tensile strength and compressive strength) became higher along with active cross-linking bonding of the epoxy resin. Medium curing type epoxy relatively had lower exothermic heat and slower reaction during curing process. It was observed to be put to definite point of mechanical strength under lower content of hardener than official ratio. While, hardener ratio more than twice the resin slowed down the curing greatly and lowered the adhesion strength also. In conclusion, under the lower mixing rate of hardener than official ratio would show relatively fast reaction with similar mechanical strength. Over the official ratio on the other hand, material property drops rapidly. Accordingly, mixing ratio of epoxy resin is expected to be influential to the stability of cultural heritage.

Mechanical Properties of Rapid-Setting Latex Modified Mortar for Antifoam Agent Type and Content (소포제 종류 및 혼입률에 따른 초속경 라텍스개질 모르타르의 역학적 특성)

  • Lee, Bong-Hak;Hong, Chang-Woo;Lee, Joo-Hyung;Kim, Dong-Ho
    • Journal of Industrial Technology
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    • v.21 no.B
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    • pp.249-256
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    • 2001
  • The purpose of this study was to remove the excessive air foaming which was produced in mixing the RSLMC(latex-modified concrete with rapid-setting cement) by choosing the best antifoam agent type. A series of RSLMM(latex-modified mortar with rapid-setting cement) experiments were carried out as a basic experiments for RSLMC with the main experimental variables such as antifiamer types(A, B, C, D), antifoamer contents(0, 1, 2, 3%), and latex contents(10, 15%). Air content test and compressive strength tests were carried out to measure the improved properties of RSLMM. SEM analysis, also, was carried to observe the formation of latex film. The results of RSLMM showed that the decrease of 50% air content was obtained by admixturing an antifoam agent by 1%. This made the strength enhanced and the workability be within the purposed. The best properties of compressive strengths was obtained at latex content of 15% and D antifoam agent of 1%. compressive strength increased about 32.6%. The analysis of SEM results no difference in a formation of later film.

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Effect of Antifoamer into Latex Modified Concrete with Rapid-Setting Cement (소포제가 초속경 라텍스개질 콘크리트에 미치는 영향)

  • 최상릉;이주형;김동호;김기헌;김경진
    • Proceedings of the Korea Concrete Institute Conference
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    • 2002.05a
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    • pp.355-360
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    • 2002
  • The purpose of this study was to remove the excessive air foaming which was produced in mixing the RSLMC(latex-modified concrete with rapid- setting cement) by choosing the best antifoam agent type and the optimized quantity for performance improved RSLMC. A series of RSLMM(latex-modified mortar with rapid-setting cement) experiments were carried out as the basic for RSLMC with the main experimental variables such as antifiamer types(A, B, C, D), antifoamer contents(0, 1, 2, 3%). Air content test and compressive, flexural tests were carried out to measure the improved properties of RSLMM and RSLMC. Chloride ion permeability test was carried out to estimate water permeability resistance. The results of RSLMM showed that the decrease of 50% air content was obtained by admixturing a antifoam agent by 1%. The compressive strength and flexural strength at 3 hours after RSLMC placement were 235kgf/cm$^2$ and 49kgf/cm$^2$, respectively, which exceeded the flexural strength criterion of 45kgf/cm$^2$ in order to open the RSLMC placed to traffic. The chloride permeability using A and C antifoamer at 28 days were below 100 coulombs, which was the permeability rating of negligible according to ASTM.

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Type of Solution and the Effects of Temperature Change in a Rapid Appraisal of Cement Fineness with a Liquid Densimeter (액체밀도계에 의한 시멘트의 분말도 신속평가에서 용액 종류 및 온도변화의 영향)

  • Lee, Jae-Jin;Kim, Min-Sang;Moon, Byeong-Yong;Kim, Yeong-Tae;Han, Min-Cheol;Han, Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2017.05a
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    • pp.167-168
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    • 2017
  • With the recent increase in demand for construction there has been an increase in the use of the raw material cement when mixing concrete; managing quality of cement powder, therefore, is most important. Therefore this study sought at first to develop a rapid appraisal using the Hydrometer method researched previously, for it was thought that when suspending cement in a solution and applying the Hydrometer method to it the temperature changes in the solution would have a great effect on the density value of the Hydrometer method; yet there has been no report of such influence factors. Therefore after analyzing the influence factors that the type of suspending solution and changes in temperature could have on rapid appraisal of fineness, using the Hydrometer method, this study was able to determine that using water at 20℃ was the most appropriate, and with every temperature increase of 10℃ the value of fineness should also be increased above or below 7% as well.

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Effect of Hydrogen in Rapid Thermal Annealing on the Graphene-Zinc Oxide Electrode for Supercapacitor (슈퍼커패시터용 그래핀-산화아연 전극의 급속열처리에서 수소의 영향)

  • Jeong, Woo-Jun;Oh, Ye-Chan;Kim, Sang-Ho
    • Journal of the Korean institute of surface engineering
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    • v.52 no.3
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    • pp.123-129
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    • 2019
  • With recent demand for the renewable energy resources, we conducted a research on the energy conversion and storage device of supercapacitor. The hybrid graphene-zinc oxide(GZO) electrodes for the supercapacitors (SCs) were fabricated and investigated. To increase the electrical conductivity of the GZO electrode, the rapid thermal annealing(RTA) in $Ar/H_2$(10%) atmosphere was applied and the effect was examined by comparing it with RTA at Ar atmosphere. In Raman spectroscopy, the electrodes annealed at 400? in $Ar/H_2$ atmosphere showed a lower ratio of D/G peak than that of annealed at Ar atmosphere, and had a larger specific capacitance(Sc) in the cyclic voltammetry(CV), and a lower the equivalent series resistance(ESR) in the electrochemical impedance spectroscopy(EIS). The reason seems to come from the better mixing of the graphene and zinc oxide by the RTA in $Ar/H_2$(10%).

A Study on the Frictional Resistance Chracteristics of Pressurized Soil Nailing Using Rapid Setting Cement (초속경 시멘트를 사용한 가압식 쏘일네일링의 주입시간에 따른 마찰저항특성에 관한 연구)

  • Lee, Arum;Shin, Eunchul;Lee, Chulhee;Rim, Yongkwan
    • Journal of the Korean Geosynthetics Society
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    • v.17 no.4
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    • pp.1-10
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    • 2018
  • Although the soil nailing method is generally used as a gravity grouting, the development and application of pressurized grouting method has recently increased to address the problem of joint generation and filling due to grouting. Pressurized grouting of the soil nailing method is generally used in combination with ordinary portland cement and water. In the field, the cement is mixed with the rapid setting cement to reduce curing time because ordinary portland cement takes more than 10 days to satisfy the required strength. In this study, uniaxial compression tests and laboratory tests were carried out to confirm the efficiency of the grouting material according to the mixing ratio of rapid setting cement. The mixing ratio of 30% grouting satisfies the required strength within 7 days and satisfies the optimum gel time. As a result of the laboratory test with granite weathered soil, the reinforcing effect was confirmed to be 1.5 times as compared with the gravity type at an injection time of 10 seconds and a strain of 15%. The friction resistance increases linearly with the increase of the injection time, but it is confirmed that the friction resistance decreases due to the hydraulic fracturing effect at the injection time exceeding the limit injection pressure. Numerical analysis was performed to compare the stability of slopes not reinforced with slopes reinforced with gravity and pressurized soil nailing.

Engineering Characteristics Assessment of Rapid Set Controlled Low Strength Material for Sewer Pipe Using Excavated Soil (굴착토를 활용한 속경성 유동성 채움재의 공학적 특성 평가)

  • Kim, Young-Wook;Lee, Bong-Chun;Jung, Sang-Hwa
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.8 no.4
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    • pp.450-457
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    • 2020
  • In this study, engineering characteristics such as flowability, segregation and compressive strength by age to derive fast hardening material mixing proportion using excavated soil. And based on optimal mixing proportion, field simulation experiment conducted in laboratory to examine the effectiveness of the method such as kelly ball drop test and soil penetration test for reviewing the following process. As as a result of evaluation, in case of kelly ball drop test and soil penetration test were securing the following process initiation time 3 hours after place CLSM. As results of these assessments, kelly ball drop test and soil penetration test were applicable for revewing following process in construction field besides unconfined compressive strength method.

Study on the Use of Sardine Meal Koji and Autolysates from Sardine Meat in Rapid Processing of Sardine Sauce (자가 소화액 및 정어리 기질 코오지를 이용한 속성 정어리 액젓 제조에 관한 연구)

  • KIM Young-Myoung;KOO Jae-Geun;LEE Young-Chul;KIM Dong-Soo
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.23 no.2
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    • pp.167-177
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    • 1990
  • Rapid production of sardine sauce using sardine meal koji and autolysate from sardine meat was investigated. The sardine meal koji was prepared by mixing sterillized sardine meal with $10\%$ flour and $10\%$ soy sauce koji, and cultivating the mixture for 48hrs at $30^{\circ}C$ and $80\%$ R. H. For sardine autolysate preparation, chopped sardine was mixed with water (10:8= sardine:water, w/w) and autolyzed for 6hrs at $550^{\circ}C$. The optimum temperature and salinity were $40^{\circ}C$ and $15\%$ for rapid fermentation of sardine sauce. Sardine sauce were prepared experimentally under 10 kinds of conditions and fermented for 20 days. The excellent effects of sardine meal koji and autolysates from sardine meat on rapid processing of sardine sauce were showed in enhancing its flavor and advancing of nitrogenous compounds.

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