• Title/Summary/Keyword: 기포제 종류

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A Study on the Performance of Foamed Concrete for Cores Material of Metal Vacuum Insulation Panel (금속진공단열패널의 심재용 기포콘크리트의 성능에 관한 연구)

  • Hong, Sang-Hun;Kim, Bong-Joo
    • Journal of the Korea Institute of Building Construction
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    • v.20 no.5
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    • pp.417-423
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    • 2020
  • In order to reduce cooling and heating, which is 40% of the energy consumption of buildings, it is important to improve the insulation of the skin. In order to improve the existing insulation, research is being conducted to apply a vacuum insulation panel(VIP) to buildings. However, VIP cannot be repaired, so we considered the metal vacuum insulation panel. Since the core of the metal vacuum pressure and have low thermal conductivity, foam concrete is adopted. However, preliminary experiments confirmed that the time to reach 0.001torr differs depending on the amount and nature of the bubbles. This effect is determined by the type of foaming agent and the density of the bubble slurry, the vacuum delivery time is determined to be the optimum foam concrete conditions are necessary. Therfore, this study aims to present basic data applicable to core materials by measuring vacuum delivery time and thermal conductivity change according to the foaming agent type and foam slurry density of foam large concrete which is core material of metal vacuum insulation panel. Experimental results and analysis show that compressive strength can be used regardless of the type of foam, In terms of thermal conductivity, it is stable to use vegetable foaming agents at 0.9g/㎤ or less. In terms of the vacuum delivery time, the foaming agent appeared similar regardless of the type of foaming agent, but it is considered suitable to use vegetable foaming agent based on compressive strength and thermal conductivity.

A Study on Fabrication and Characterization of Inorganic Insulation Material by Hydrothermal Synthesis Method (2) (수열합성법을 이용한 무기계 단열소재 제조방법 및 특성에 관한 연구 (2))

  • Seo, Sung-Kwan;Chu, Yong-Sik;Lee, Jong-Kyu;Song, Hun;Park, Jae-Wan
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.1 no.3
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    • pp.225-232
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    • 2013
  • The inorganic insulating material was fabricated with quartzite, ordinary portland cement(OPC), lime, anhydrous gypsum and foaming agent by hydrothermal reaction. The inorganic insulating material was fabricated by using autoclave chamber under high-temperature and high-pressure. The inorganic insulating material is a porous lightweight concrete. Because of its porous structure, properties of inorganic insulating material were light-weight and high-heat insulation property. Properties of fabricated inorganic insulating material were $0.26g/cm^3$ in specific gravity, 0.4MPa in compressive strength and 0.064W/mK in thermal conductivity. In this study, the inorganic insulating material was fabricated and analyzed at different size of quartzite/OPC, various foaming reagent and functional additives to improve the properties. Consequently, polydimethylsiloxane can improve density and thermal conductivity. Especially, polydimethylsiloxane showed excellent improvement in compressive strength.

Effect of Chemical Conditioning on Flotation and Thickening Properties of Sludge using a Microbubble Generating Pump (화학적 개량이 미세기포 발생펌프를 이용한 슬러지 부상농축에 미치는 영향)

  • Lee, Chang-Han;Ahn, Kab-Hwan
    • Journal of Korean Society of Environmental Engineers
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    • v.31 no.8
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    • pp.641-648
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    • 2009
  • The study presents sewage sludge flotation and thickening efficiencies which changes chemical conditioning and mixing conditions using a flotation thickening system with a microbubble generating pump. Flotation and thickening of sewage sludge are shown to significantly influence kinds of coagulants more than Gt values. It is found that the flotation and thickening efficiencies for kinds of coagulants follows the order: $Al_2(SO_4)_3$ < PSO-M < $Fe_2(SO_4)_3$. We shows that the flotation thickening system(1.6 $m^3$/d) could be continuously operated during two hours on operation conditions in the lab-scale experiments. Sludge thickening efficiency in the A/S ratio of 0.029 - 0.019 mL/mg was found to be very efficient, reaching to 300.0~335.7%.

Properties of Lightweight Foamed Concrete According to Animality Protein Foaming Agent Type (동물성 기포제 종류별 경량기포 콘크리트의 특성)

  • Lim, Jeong-Jun;Lee, Sang-Soo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2019.05a
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    • pp.34-35
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    • 2019
  • In recent years, the construction industry has also applied the dry method that can be assembled in the field by industrialization and factory production, which is free from climatic effects and can reduce the cost due to mass production and simplify the work in the field. Among the building materials used in this dry method, ALC products are made by mixing calcium oxide, gypsum, cement, and water in silica and putting them in an autoclave to create voids in the interior through steam curing at high temperature and pressure. But it requires curing cycle conditions of warming, isothermal, and temperature curing. It depends on the performance of the product depending on the curing conditions, the economical efficiency due to high oil prices, the emission of greenhouse gases by the use of fossil fuels. Experiments were conducted to select an appropriate animal protein foam for lightweight foamed concrete block which was cured by applying a prefilling method to replace existing ALC products. As a result of investigating the characteristics of lightweight foamed concrete by type of animal protein foam, it is considered that FP3 is most suitable for manufacturing lightweight foamed concrete block.

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A study on the estimation of bubble size distribution using an acoustic inversion method (음향 역산법을 이용한 기포의 크기 분포 추정 연구)

  • Park, Cheolsoo;Jeong, So Won;Kim, Gun Do;Moon, Ilsung;Yim, Geuntae
    • The Journal of the Acoustical Society of Korea
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    • v.39 no.3
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    • pp.151-162
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    • 2020
  • This paper presents an acoustic inversion method for estimating the bubble size distribution. The estimation error of the attenuation coefficient represented by a Fredholm integral equation of the first kind is defined as an objective function, and an optimal solution is found by applying the Levenberg-Marquardt (LM) method. In order to validate the effectiveness of the inversion method, numerical simulations using two types of bubble distribution are performed. In addition, a series of experiments are carried out in a water tank (1.0 m × 0.54 m × 0.6 m), using bubbles generated by three different generators. Images of the distributed bubbles are obtained by a high-speed camera, and the insertion losses of the bubble layer are measured using a source and a hydrophone. The image is post-processed to glance a distribution characteristics of each bubble generator. Finally, the size distribution of bubbles is estimated by applying the inversion method to the measured insertion loss. From the inversion results, it was observed that the number of bubbles increases exponentially as the bubble size decreases, and then increases again after the local peak at 70 ㎛ - 120 ㎛.

A Review of the Physical Performance of Lightweight Aerated Concrete for Use as an Interior Core Material in Fire Doors (방화문 내부 심재로 적용하기 위한 경량기포콘크리트의 물리적 성능 검토)

  • Hong, Sang-Hun;Kim, Bong-Joo;Jung, Ui-In;Kim, Hae-Nah;Park, Jun-Seo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2023.05a
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    • pp.111-112
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    • 2023
  • With the development of cities, the density of the population is continuously increasing as buildings become larger and more high-rise, but since the Haeundae residential complex fire in Busan in 2010, there has been a growing need to meet the fire protection performance of buildings as large-scale fires continue to occur every year. On the other hand, fire doors, which are one of the fire protection performance of buildings, have been judged unqualified in 82% of cases when fire doors constructed on the actual site were inspected after completion. The reason for this is that paper honeycomb and glasswool, which are used as core materials for fire doors, absorb moisture, reducing thermal insulation performance, and sagging due to increased weight, leading to performance degradation due to warping in empty spaces. To overcome these problems, research is underway to apply lightweight aerated concrete, an inorganic material, as a core material. Therefore, in order to select a blowing agent that produces stable bubbles prior to the production of lightweight bubble concrete for application as a fire door inner core, this study examined the physical performance according to the type of blowing agent and dilution concentration, and the following conclusions were drawn. Compared to vegetable bubbles and independent bubbles, synthetic bubbles have 3~8% higher thermal conductivity than independent bubbles, but 3~6% lower slurry density than vegetable bubbles, and 2~13% higher compressive strength, which is thought to be an improvement of synthetic bubbles.

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Reviewing the fireproofing of lightweight aerataed concrete for fire door interior cores (방화문 내부 심재용 경량기포콘크리트의 방화성 검토)

  • Hong, Sang-Hun;Kim, Bong-Joo;Jung, Ui-In;Kim, Hae-Nah;Park, Jun-Seo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2023.11a
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    • pp.43-44
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    • 2023
  • Fire doors installed to prevent the spread of fire in buildings are made of paper honeycomb, glass wool, and other materials. Due to their high water absorption rate, they absorb ambient moisture and degrade, and their increased weight causes them to sag internally, creating voids that can warp in the event of a fire and allow flames to pass through. To overcome these issues, research is being conducted on the physical performance of lightweight aerated concrete. However, there is a lack of research on how to ensure fire resistance. Therefore, in this study, the backside temperature of lightweight aerated concrete formulations was measured and compared and analyzied with the physical performance. Since it is difficult to achieve low density by saturation alone, aerated concrete with EPS was produced, which resulted in a density reduction of 24'26%, but the strength increase per unit cement increase was 5'25%, which tended to be lower than the formulation without EPS. The results showed that the lightweight aerated concrete with EPS was 130~140℃ lower than the lightweight aerated concrete with EPS, which is believed to be due to the melting point of EPS delayed the heat diffusion. In the future, wo plan to conduct research to identify the optimal formulation for fire door core materials by varying the amount of EPS added and using industrial by-products to increase long-term strength.

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A Study on the Shape and Movement in Dissolved Air Flotation for the Algae Removal (수중조류제거(水中藻類除去)를 위한 가압부상(加壓浮上)에 있어서 기포(氣泡)의 양태(模態)에 관한 연구(研究))

  • Kim, Hwan Gi;Jeong, Tae Seop
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.4 no.4
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    • pp.79-93
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    • 1984
  • The dissolved air flotation(DAF) has been shown to be efficient process for the removal of algae ftom water. The efficiency of DAF can be affected by the volume ratio of pressurized liquid to sample, the pressure pressurized liquid, the contact time, the appropriate coagulant and its amount, the water temperature, the turbulence of reactor, the bubble size and rising velocity etc. The purpose of this paper is to compare the practical bubble rising velocity with the theoretical one, to investigate the adhesion phenomenon of bubbles and floc, and the influence of bubble size and velocity upon the process. The results through theoretical review and experimental investigation are as follows: Ives' equation is more suitable than Stokes' equation in computation of the bubble rising velocity. The collection of bubble and algae floc is convective collection type and resulted from absorption than adhesion or collision. The treatment efficiency is excellent when the bubble sizes are smaller than $l00{\mu}m$, and the turbulence of reactor is small. In the optimum condition of continuous type DAF the volume ratio of pressurized liquid to sample is 15%, the contact time in reactor is 15 minutes, the pressure of pressurized liquid is $4kg/cm^2$ and the distance from jet needle to inlet is 30cm.

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Application of Various Types of Surfactants for Improving Hydrophilic Properties of Polyvinylsiloxane Dental Rubber Impression Materials and its Effects on Physical Properties (폴리비닐실록산 치과용 고무인상재의 친수성 향상을 위한 계면활성제의 응용과 물성에 미치 는 영향)

  • Park, Yeong-Joon;Hwang, Moon-Jin;Kim, Min-Kang;Song, Ho-Jun;Ha, Kwang;Kang, Shin-Young
    • Elastomers and Composites
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    • v.43 no.2
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    • pp.88-103
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    • 2008
  • This study was purposed to investigate the effects of surfactants and fillers on physical properties of hydrophilic polyvinylsiloxane dental impression materials (PVS). Incorporation of surfactants enhanced the hydrophilicity of the PVS, however, it induced increased viscosity and permanent deformation ratio, delayed setting, and decreased tensile strength. At high concentrations of surfactant, the tensile strength was observed to decrease significantly due to the internal pore formation. Especially, the hydrophilicity of the PVS was significantly enhanced with the addition of Silwet L-77. However, the viscosity, strain in compression, pore formation, and setting time increased whereas the elastic recovery rate and strength remarkably decreased. The PVS dental materials containing Span 20 showed the lowest degree of viscosity increase, delayed setting, pore formation, and hydrophilicity. The delayed setting, pore formation, and strength decrease caused by the incorporation of surfactant were improved by substituting the crystalline quartz filler with diatomaceous earth while the contact angle of PVS dental materials increased.

Enhancement of Wetting Characteristics for Anisotropic Conductive Adhesive with Low Melting Point Solder via Carboxylic Acid-based Novel Reductants (카르복실산계 환원제를 통한 저융점 솔더입자가 포함된 이방성 전도성 접착제의 젖음 특성 향상 연구)

  • Kim, Hyo-Mi;Kim, Joo-Heon
    • Polymer(Korea)
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    • v.34 no.1
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    • pp.52-57
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    • 2010
  • The low viscous epoxy resin(bisphenol F) with carboxylic acid as the reductants was introduced for high performance and reliability in the ACA with a low melting point alloy filler system. The curing characteristics of the epoxy resin and temperature dependant viscosity characteristic of epoxy resin at the melting temperature of LMPA were investigated by dynamic mode of differential scanning calorimetry (DSC) and rheometer, respectively. Based on these thermo-rheological characteristics of epoxy resin and LMPA, the optimum process system was designed. In order to remove the oxide layer on the surface of LMPA particle, three different types of carboxyl acid-based reductant were added to the epoxy resin. The wetting angles were about $18^{\circ}$ for carboxypropyldisilioxane, and $20.3^{\circ}$ for the carboxy-2-methylethylsiloxane, respectively.