• Title, Summary, Keyword: Material Mixing Method

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A study of mixing ratio of seal material for umbrella arch reinforcement for tunnelling (터널 강관 보강형 다단 그라우팅의 Seal재 배합비에 대한 연구)

  • Hwang, Beoung-Hyeon;Kim, Yeon-Deok;Sim, Jae-Hoon;Kim, Sang-Hwan
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.22 no.4
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    • pp.367-381
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    • 2020
  • This paper presents the seal material mixing ratio of tunnel umbrella arch reinforcement method. Currently, there is no clear standard for the proper gelation time and curing time of the Seal material in Korea, and the quality control is also difficult because it cannot be verified. In response, the ratio of the mixture of the seal material was composed of four types of indoor experiments, and the amount of gelation time and bleed was checked. In addition, a non-cart penetration test confirmed the curing time and compared the ratio of each combination. Further experiments on W/C 120% identified the effect of mixing speed and time on the seal material. A total of three field experiments were conducted based on indoor experiments, and the size and strength of bulb formation were compared by checking the curing time of the specimen and main injection. Comparisons show that the lower W/C, the stronger the strength, the larger the size of the bulb, and the faster the hardening time appears. Based on the results of the gelation time and curing time, it was deemed that the mixing ratio of W/C 120% is most appropriate when applied to the actual site.

Rational Method of CLSM Mixture with Sewage Sludge Cinder (하수슬러지를 활용한 저강도 콘크리트의 합리적 배합방법)

  • Kim, Dong-Hun;Takashi, Horiguchi;Lim, Nam-Gi
    • Journal of the Korea Concrete Institute
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    • v.24 no.4
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    • pp.465-472
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    • 2012
  • This research aims to find an effective mixing method for controlled low strength material (CLSM) using diverse recycled industrial byproducts. This study is a fundamental research to develop and commercialize a resource-recycling CLMS that can greatly contribute to cost reduction and environmental stress relief. In the past, few studies have been performed on CLSM in Korea. This research is expected to provide fundamental data not only for development and commercialization of the resource-recycling CLSM satisfying required material performances but also serve as a ground breaking study on utilization of recycled material in construction industry and ultimately leading to advanced resource-recycling practices at national level. From the comprehensive analysis of minimum unit quantity for maximum strength and material segregation prevention, it was found that the optimal mixing condition for mixing FSD, RSID and SD material to filler-aggregate ratio (f/a) was approximately 50.

A New Method for Analysis of Capsaicinoids Content in Microcapsule. (미세캡슐내의 캡사이시노이드의 새로운 분석법)

  • Jung, Jong-Min;Kang, Sung-Tae
    • Korean Journal of Food Science and Technology
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    • v.32 no.1
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    • pp.42-49
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    • 2000
  • A new method for the quantitative determination of capsaicinoids in microcapsule has been developed. Among seventeen solvents tested for solubilizing wall material (gum arabic and modified starch) of microcapsule, dimethyl sulfoxide (DMSO) was selected as an optimal solvent. The most appropriate mixing ratio of microcapsule to DMSO for solubilizing wall material was 1 to 10(w/v). Appropriate carriersolubilizing temperature and time were $55^{\circ}C$ and 30 min, respectively. Also conditions for extracting oleoresin from the solubilized microcapsule were studied. The mixing ratio of ethanol to DMSO was optimal at 8 to 1(v/v). Optimized vortexing time was 5 min at 40㎐. Pecipitant was obtained by centrifugation at 21000 rpm for 15 min. The precipitant was reextracted with ethanol. The extracted supernatants were combined and adjusted to final volume of 25 ml. Extracted solutions were analyzed for quantitation of total capsaicinoids by employing HPLC and for quantitation of total carotenoids by spectrophotometric method. This method can be used to monitor changes of capsacinoid during manufacturing or storage of red pepper oleoresin microcapsule powder.

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Estimation of Specific Gravity of Soil Mixture (배합비에 따른 혼합토의 비중 산정)

  • Shin, Hyun-Young;Kim, Kyoung-O;Kim, You-Seok;Park, Jin-Yoo
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.951-954
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    • 2010
  • There are lots of soft ground improvement methods which is consist of different materials. In the analysis and design, composite ground method is usually regarded. Composite ground method considers the area replacement ratio as a key parameter to combine the physical and mechanical characteristics of tow different material. In this study, using composite material consist of three different materials which have different diameters, series of specific gravity test were performed according to KS F 2308, to investigate the applicability of composite ground method. As a result, it is found that composite material which is consist of fine grained soil and granular soil has a high applicability of composite ground method. This result means that, in estimating of ground properties of composite material which is consist of similar fine grained material such as cement mixing etc., composite ground method has a less applicability.

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Mechanical Properties of Recycled Coarse Aggregate concrete using Two-Stage Mixing Approach (TSMA 방법을 이용한 순환 굵은골재 콘크리트의 기계적 성능)

  • Kwon, Seung Jun;Lim, Hee Seob;Lee, Han Seung;Lim, Myung Kwan
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.22 no.4
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    • pp.60-67
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    • 2018
  • As the lack of specific aggregation intensifies, the development of alternative resources is urgent. Construction waste is increasing every year, but recycled aggregate is used as a low value added material. Various studies are currently underway at the national level. In this paper, the mechanical performance of the concrete according to the concrete mixing method and the replacement amount of the circulating coarse aggregate was compared and evaluated. Concrete mixing method was normal mixing approach(NMA) method, two-stage mixing approach1 (TSMA1) method, two-stage mixing approach2 (TSMA2) method. Fresh concrete was tested for air content, slump test, and unit volume weight. Compressive strength and flexural strength were tested in hardened concrete. According to the TSMA method, the mechanical performance difference of concrete is shown, and the strength is decreased according to the circulating coarse aggregate replacement amount.

The Properties of OPC-Slag Cement Mixed with Nano-Silica Solution by Mixing Water Weight Replacement Method (나노실리카 졸을 배합수 중량치환 방법으로 혼합한 OPC-slag cement의 특성)

  • Seo, Ki-Young;Kim, Taewan;Kim, Seong-Do
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.24 no.1
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    • pp.24-34
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    • 2020
  • This research is a study on the characteristics of OPC-slag cement using nano-silica solution (NSS) with water-weight substitution method. The new replacement method is a fundamental step to study the behavior of cement with higher NSS replacement rates than previous studies. NSS was replaced by 10%, 20%, 30%, 40%, and 50% of the mixing water weight. As a result, the mechanical and microstructural characteristics were improved. This can be summarized in two ways. First, when the NSS is replaced with mixing water, the homogeneous dispersion action of the nano-silica particles is improved. This promotes initial hydration. Second, substitution of NSS with higher density than mixing water reduces w / b. This forms a dense hydration reaction material. The new substitution method did not show any degradation of mechanical and microstructural properties as compared with the results using the powdered nano-silica particles revealed in the previous study. Therefore, it is considered that the method of weight substitution of NSS used in this study can be applied to the formulation of OPC-slag cement.

Multi-material topology optimization of Reissner-Mindlin plates using MITC4

  • Banh, Thien Thanh;Lee, Dongkyu
    • Steel and Composite Structures
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    • v.27 no.1
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    • pp.27-33
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    • 2018
  • In this study, a mixed-interpolated tensorial component 4 nodes method (MITC4) is treated as a numerical analysis model for topology optimization using multiple materials assigned within Reissner-Mindlin plates. Multi-material optimal topology and shape are produced as alternative plate retrofit designs to provide reasonable material assignments based on stress distributions. Element density distribution contours of mixing multiple material densities are linked to Solid Isotropic Material with Penalization (SIMP) as a design model. Mathematical formulation of multi-material topology optimization problem solving minimum compliance is an alternating active-phase algorithm with the Gauss-Seidel version as an optimization model of optimality criteria. Numerical examples illustrate the reliability and accuracy of the present design method for multi-material topology optimization with Reissner-Mindlin plates using MITC4 elements and steel materials.

Mixing Effect by the Geometry of Static Mixer with Turbulent In-Situ Mixing Process (난류 용탕 In-Situ 합성법을 위한 스태틱 믹서의 형상에 따른 혼합 효과)

  • Lee, Dae-Sung;Kim, Hyo-Geun;Ha, Man-Yeong;Park, Yong-Ho;Park, Ik-Min
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.29 no.12
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    • pp.1307-1312
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    • 2005
  • Turbulent in-situ mixing process is a new material process technology to get dispersed phase in nanometer size by controlling reaction of liquid/liquid, liquid/solid and liquid/gas, flow and solidification speed simultaneously. In this study mixing, the key technology to this synthesis method will be studied by computational fluid dynamics. For the simulation of mixing of liquid metal, static mixers will be investigated. Two inlets for different liquid metal meet and merge like 'Y' shape tube. The tube has various shapes such as straight and curved. Also, the radius of curve will be varied. The performance of mixer will be evaluated with quantitative analysis with coefficient of variance of mass fraction. Also, detailed plots of intersection will be presented to understand effect of mixer shape on mixing.

Seed Germination Study to Determine the Feasibility of Local Resources as Materials for Ecological Restoration (생태복원용 소재로서 현지자원의 이용가능성 파악을 위한 발아실험 연구)

  • Kim, Kyung-Hoon;Kim, Young;Joo, Paik;Hur, Young-Jin
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.18 no.1
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    • pp.153-163
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    • 2015
  • The study was conducted to develop ecological restoration method of damaged area in DMZ vicinities. As the material for the ecological restoration, forest soil and trees waste have been used. Forest soils were collected for experiments in Yanggu, Gangwon Province. Effect of ecological restoration was analyzed through germination experiment. Germination experiment was performed using 12 kinds of woody and herbaceous seeds. Woody and herbaceous seed germination in test pot was relatively evenly. Mixed material consisting of forest soil and trees waste seemed a possibility as the material for the restoration. The effects on seed germination were higher in the case of mixing more than 70% by volume ratio of local resources. Total number germinated individuals were different depending on the mixing ratio of soil sampling depth. Individual plants showed different trends depending on the experimental combination. Results of the woody seed germination were affected only in the soil sampling depth. Seed germination of herbaceous received a combined effect on soil sampling depth and mixing ratio.

A THERMO-ELASTO-VISCOPLASTIC MODEL FOR COMPOSITE MATERIALS AND ITS FINITE ELEMENT ANALYSIS

  • Shin, Eui-Sup
    • Journal of Theoretical and Applied Mechanics
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    • v.3 no.1
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    • pp.45-65
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    • 2002
  • A constitutive model on oorthotropic thermo-elasto-viscoplasticity for fiber-reinforced composite materials Is illustrated, and their thermomechanical responses are predicted with the fully-coupled finite element formulation. The unmixing-mixing scheme can be adopted with the multipartite matrix method as the constitutive model. Basic assumptions based upon the composite micromechanics are postulated, and the strain components of thermal expansion due to temperature change are included In the formulation. Also. more than two sets of mechanical variables, which represent the deformation states of multipartite matrix can be introduced arbitrarily. In particular, the unmixing-mixing scheme can be used with any well-known isotropic viscoplastic theory of the matrix material. The scheme unnecessitates the complex processes for developing an orthotropic viscoplastic theory. The governing equations based on fully-coupled thermomechanics are derived with constitutive arrangement by the unmixing-mixing concept. By considering some auxiliary conditions, the Initial-boundary value problem Is completely set up. As a tool of numerical analyses, the finite element method Is used with isoparametric Interpolation fer the displacement and the temperature fields. The equation of mutton and the energy conservation equation are spatially discretized, and then the time marching techniques such as the Newmark method and the Crank-Nicolson technique are applied. To solve the ultimate nonlinear simultaneous equations, a successive iteration algorithm is constructed with subincrementing technique. As a numerical study, a series of analyses are performed with the main focus on the thermomechanical coupling effect in composite materials. The progress of viscoplastic deformation, the stress-strain relation, and the temperature History are careful1y examined when composite laminates are subjected to repeated cyclic loading.

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