• Title/Summary/Keyword: Rapid Mixing

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Synthesis and Characteristics of Hyaluronic Acid Bead Crosslinked by 1,3-Butadiene diepoxide (1,3-Butadiene diepoxide에 의해 가교된 히아루론산 비드의 제조 및 특성)

  • Kwon, Ji-Young;Cheong, Seong-Ihl
    • Polymer(Korea)
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    • v.29 no.5
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    • pp.445-450
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    • 2005
  • Hyaluronic acid-based beads were prepared in order to develop a biomedical material for augumentation. Hyaluronic acid was crosslinked by 1,3-butadiene diepoxide in a suspension state maintained by rapid mixing of soybeen oil and hyaluronic acid solution. The particle size, surface area and swelling ratio were measured to investigate the physical properties of the synthesized beads and the bead surface was examined by scanning electron microscopy. The beads were formed in the range of $5-12vol\%$ concentration of crosslinking agent, which showed monodisperse size distribution. Both BET surface area and swelling ratio decreased as the concentration of either hyaluronic acid or crosslinking agent increased, and crosslinking temperature decreased. Bead size could be effectively controlled by mixing speed without affecting other physical property.

The Risk Assessment of Runway Reaction in the Process of Fridel-Crafts Acylation for Synthesis Reaction (화합물 합성반응 중 Fridel - Crafts Acylation 공정에서의 폭주반응 위험성평가)

  • Lee, Kwangho;Kim, Wonsung;Jun, Jinwoo;Joo, Youngjong;Park, Kyoshik
    • Journal of the Korean Society of Safety
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    • v.36 no.3
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    • pp.24-30
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    • 2021
  • Heat is generated during the synthesis and mixing process of chemical compounds due to a change in activation energy during the reaction. A runaway reaction occurs when sufficient heat is not removed during the heat control process within a reactor, rapidly increasing the temperature, reaction speed, and rate of heat generation inside the reactor. A risk assessment was executed using an RC-1 (Reaction Calorimeter) during Friedel-Crafts acylation. Friedel-Crafts acylation runs the risk of rapid heat generation during Active Pharmaceutical Ingredient (API) manufacturing; it was used to confirm the risk of a runaway reaction at each synthesis stage and during the mixing process. This study used experimental data to develop a safety efficiency improvement plan to control the risks of runaway and other exothermic reactions, which was implemented at the production site of a chemical plant.

Properties of Fresh Mortar Mixed with Steel Furnace Slag Powder (제강슬래그 분말을 혼입한 굳지 않은 모르타르의 특성)

  • Lee, Jeong-Taek;Lee, Sang-Soo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2023.11a
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    • pp.33-34
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    • 2023
  • Currently, research on construction materials using industrial by-products is being conducted in the Inhan construction industry due to CO2 emissions during the cement production process and a shortage of aggregates. Among these, research has been conducted to use steel furnace slag as an aggregate by reducing the reactivity of free-CaO, which has the characteristic of expanding through open storage, aging, and rapid cooling. However, research on the use of powder as a cement admixture or substitute is insufficient. Therefore, this study aims to analyze the properties of fresh mortar using steel furnace slag powder. The mixing ratio of steel furnace slag powder was divided into three levels: 0, 20, and 40 (%), and the test items were flow and unit weight. The experimental results showed that as the mixing ratio of steel furnace slag powder increased, flow and unit weight tended to increase. Therefore, it is expected to have a positive effect on improving workability or strength as a cement admixture.

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Heat Performance of Rapid Hardening Nano-Cementitious Composite for Repairing of Concrete Structures (콘크리트 구조물 보수를 위한 초속경 나노-시멘트 복합체의 발열성능)

  • Cho, Sanghyeon;Lee, Heeyoung;Yu, Wonjun;Kim, Donghwi;Chung, Wonseok
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.8 no.4
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    • pp.421-428
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    • 2020
  • Recently, excellent thermal and electrical performance of cementitious composites by mixing nano materials are being studied. The purpose of this study is to research the heat generation and power consumption of rapid hardening nano-cementitious composites. The experiment was carried out after setting the rapid hardening cementitious material, curing day, and supply voltage as parameters. Rapid hardening nano-cementitious materials were classified into cement paste, mortar, and concrete The heat performance of all rapid hardening nano-cementitious composites in curing 1 day has increased over 10℃. The rapid hardening nano-cementitious composites can exhibit heat performance within 1 day. The heat performance of the rapid hardening nano-cementitious composites is maintained after 28 days.

A Study on the MHD Micropump with Mixing Function (혼합 기능을 갖는 마이크로 펌프의 연구)

  • Choi, Bum-Kyoo;Kang, Ho-Jin;Kim, Min-Sock
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.34 no.6
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    • pp.579-586
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    • 2010
  • With the development of micrototal analysis systems (${\mu}TAS$), which is a result of enhancement of MEMS technology, rapid progress has been achieved in medical and biological research. The study of lab-on-a-chip (LOC) devices, which are types of ${\mu}TAS$ and which integrate the functions of mixing and analyzing tiny amounts of samples and reagents on one chip, has actively progressed. An LOC comprises microfluidic components such as micromixers and micropumps. Because the flow in a microfluidic system is generally laminar, it is very difficult to efficiently mix and feed fluid reagents. This paper presents the design and the method of fabrication of an MHD micropump for mixing fluids. By using this micropump, fluids are simultaneously mixed and pumped; this is achieved by coupling the Lorentz force and force exerted by an electric charge moving in an electric field.

Flame Structure and Light Emission Characteristics in Coaxial Laminar Partially Premixed $CH_{4}/Air$ Flames;Effect of Central Fuel Injection (이중동축 메탄/공기 층류 부분 예혼합화염에서의 화염구조와 자발광 배출 특성;안쪽관 연료주입의 영향)

  • Oh, Jeong-Seog;Jeong, Yong-Ki;Jeon, Chung-Hwan;Chang, Young-June
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.1116-1121
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    • 2004
  • In this study, the effect of central fuel injection on a coaxial laminar $CH_{4}/air$ flame was experimented at the defined premixing condition(${\Phi}=1.90$, ${\sigma}=50/75/100%$, x/D=10). The partial premixing parameter are the equivalence ratio that total fuel is fixed at 200cc/min, the fuel split degree which means the percentage of fuel entering the outer tube to the total amount, and the mixing distance indicating the nonreactant mixture's homogeneity between inner tube top and burner exit. The object is to investigate the flame structure and chemiluminescence characteristics of laminar partial premixed flame as changing mixing parameters. The radical signal was acquired from ICCD camera and PMT. Each intensity was compared with Abel inverted value for measuring the effect of background light on the peak signal location and the intensity at central preheat zone. The results show that the peak location of each radical was broaden as the fuel split degree increasing because the mixing quality was enhanced. and $OH^{\ast}$ is a good indicator for flame front between reaction and preheat zone. At last $CH_{2}^{\ast}$ has the same tendency with $CH^{\ast}$ but a thinner reaction zone than $CH^{\ast}$ due to a rapid decay on the burned gas side.

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Remote Sensing of NO2 vertical profiles in Beijing on the basis of MAX-DOAS measurements (지상 MAX-DOAS를 이용한 중국 베이징에서의 이산화질소 연직분포 산출 및 지상자료와 비교를 통한 검증연구)

  • Ryu, Jae-Yong
    • Korean Journal of Remote Sensing
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    • v.30 no.6
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    • pp.703-708
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    • 2014
  • $NO_2$ vertical profiles were retrieved via ground based MAX-DOAS measurements for the summer period in 2006 in Beijing, one of the megacities in the Northeast Asia. Large portion of $NO_2$ load was observed at the 0-1 km layer. We found that $NO_2$ rapidly decreases up to the altitude of 3 km. In addition, the retrieved $NO_2$ mixing ratios within 0-1 km layer were compared with those observed at the surface by in-situ monitor. The correlation coefficient (R) between $NO_2$mixing ratios within 0-1 km layer and those at the surface was calculated to be 0.7. The major causes of such discrepancy are thought to be both differences in measured areas and rapid decrease in $NO_2$ mixing ratio with height.

Treatment of Livestock Wastewater with Coagulant-loess (황토를 이용한 축산폐수의 처리에 관한 연구)

  • Park, Jin-Hee;Kim, Bo-Guk;Won, Chan-Hee
    • Journal of Korean Society of Environmental Engineers
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    • v.22 no.10
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    • pp.1799-1808
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    • 2000
  • To investigate the applicability of loess as a coagulant. the optimum conditions of coagulation and efficiency comparison of several coagulants (PAC, PACS, LAS) in chemical treatment of livestock wastewater were performed. As a result, the optimum mixing ratio of loess and lime(CaO) was 3:7. The optimum dosage of the mixed coagulant was 30 g/L. The optimum speed for rapid mixing of the mixed coagulant was 200 rpm at 1 min. and the optimum speed for slow mixing was 50 rpm at 10 min. The mixed coagulant showed the removal efficiency of turbidity, SS, BOD, $COD_{cr}$. T-P and TKN to 95.8%, 92.5%, 71.6%, 71.1%, 98.2% and 32.5%, respectively, which was better than other several coagulants. The mixed coagulant was possible to use as substitutional coagulants of traditional coagulant, and the producted sludge can use as a soil amendments.

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Diffusion of a Steady Horizontal Line Source in a Turbulent Shear Flow (난류전단(亂流剪斷) 흐름에서의 정상(定常) 수평(水平) 선오염원(線汚染源)의 확산(擴散))

  • Jun, Kyung Soo;Lee, Kil Seong
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.13 no.2
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    • pp.191-199
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    • 1993
  • Diffusion of a steady horizontal line source in a turbulent shear flow is simulated by numerically solving a steady two-dimensional advective diffusion equation. The computational result is compared with the analytic solution for uniform velocity and diffusivity distributions over the depth. The analytic solution for constant velocity and diffusivity overestimates the degree of vertical mixing. The normalized equation indicates that friction factor is the only physical parameter that governs the vertical diffusion process. Sensitivities of the diffusion process to the friction factor and initial source position are analyzed. The rate of vertical mixing varies approximately as the square root of the friction factor. The optimal source position, which gives the most rapid mixing, lies above the mid-depth and moves toward the water surface as the friction factor increases.

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Morphology and Mechanical Properties of Recycled PVC Blends (III) - Morphologies and Mechanical Properties of Recycled PVC/PE Blends with Different Kinds of Compatibilizers and Mixing Conditions (폐폴리(염화 비닐)계 고분자 블렌드의 구조 및 물성 연구(III) -상용화제의 종류 및 혼합 조건에 따른 폐폴리(염화 비닐)/폴리에틸렌 고분자 블렌드의 형태학 및 물성)

  • 유영재;박재찬;원종찬;최길영;이재흥
    • Polymer(Korea)
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    • v.28 no.6
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    • pp.468-477
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    • 2004
  • The polymer blends of waste poly(vinyl chloride) (RPVC) and waste polyethylene (RPE) were prepared by melt mixing. Various ethylene-vinyl acetate copolymers (EVA) and ethylene-methacrylic acid Na salt copolymer (ionomer) were used as compatibilizer. Their morphologies and mechanical properties were evaluated as a funtion of mixing sequence and time. EVA with high vinyl acetate contents showed a rapid increment of tensile properties when small amount was added. Tensile properties of the blends were gradually increased with the addition of ionomer. Morphologies of RPVC/RPE blends were analyzed by scanning electron microscopy. FT-IR data showed that EVA was a good compatibilizer in RPVC/RPE blend compared to ionomer. Mechanical properties of the blends were highly enhanced when RPVC and compatibilizer were mixed and first RPE was added later.