• Title/Summary/Keyword: Surface Properties Test

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Effect of titanium powder on the bond strength of metal heat treatment (티타늄 파우더가 금속의 열처리 시 결합강도에 미치는 영향)

  • Kim, Sa-Hak;Kim, Wook-Tae
    • Journal of Dental Rehabilitation and Applied Science
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    • v.33 no.2
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    • pp.71-79
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    • 2017
  • Purpose: Ni-Cr alloy does not contain Beryllium, causing the metal compound to form oxides in the furnace but by using Titanium as a chemical catalyst the forming of the oxides can be controlled, and by controlling the impurities formed on the metal surface, the possibility of the Ni-Cr alloy bond strength being increased can be analysed. Materials and Methods: Titanium was used as a chemical catalyst in the porcelain for the oxidation of beryllium-free metal (Ni-Cr) alloy. The T1 group, which does not use Titanium power as a chemical catalyst is a reference model for comparison. The T2 group and T3 group used 10 g and 20 g of Titanium power, respectively. They are fabricated to observe the shear bond strength and surface properties. There was no significance when One-way ANOVA analysis/Tukey Honestly Significant Difference Test was conducted for statistical analysis among groups (P > 0.05). Results: Results of measuring the three-point flexural bond strength of the Ni-Cr alloy and thickness of the oxide film. Experiment T3 using 20 g Titanium chemical catalyst: $39.22{\pm}3.41MPa$ and $6.66{\mu}m$, having the highest bond strength and thinness of oxide film. Experiment T2 using 10 g Titanium chemical catalyst: $34.65{\pm}1.39MPa$ and $13.22{\mu}m$. Experiment T1 using no Titanium chemical catalyst: $32.37{\pm}1.91MPa$ and $22.22{\mu}m$. Conclusion: The T2 and T3 experiments using Titanium chemical catalyst showed higher bond strength for the Ni-Cr alloy and lower thickness of oxide film than experiment T1, and the titanium catalyst being able to increase bond strength was observed.

Development of an ECC(Engineered Cementitious Composite) Designed with Ground Granulated Blast Furnace Slag (고로슬래그미분말이 혼입된 ECC(Engineered Cementitious Composite)의 개발)

  • Kim, Yun-Yong;Kim, Jeong-Su;Ha, Gee-Joo;Kim, Jin-Keun
    • Journal of the Korea Concrete Institute
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    • v.18 no.1 s.91
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    • pp.21-28
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    • 2006
  • This paper presents both experimental and analytical studies for the development of an ECC(Engineered Cementitious Composites) using ground granulated blast furnace slag(slag). This material has been focused on achieving moderately high composite strength while maintaining high ductility, represented by strain-hardening behavior in uniaxial tension. In the material development, micromechanics was adopted to properly select optimized range of the composition based on steady-state cracking theory and experimental studies on matrix, and interfacial properties. A single fiber pullout test and a wedge splitting test were employed to measure the bond properties of the fiber in a matrix and the fracture toughness of mortar matrix. The addition of the slag resulted in slight increases in the frictional bond strength and the fracture toughness. Subsequent direct tensile tests demonstrate that the fiber reinforced mortar exhibited high ductile uniaxial tension behavior with a maximum strain capacity of 3.6%. Both ductility and tensile strength(~5.3 MPa) of the composite produced with slag were measured to be significantly higher than those of the composite without slag. The slag particles contribute to improving matrix strength and fiber dispersion, which is incorporated with enhanced workability attributed to the oxidized grain surface. This result suggests that, within the limited slag dosage employed in the present study, the contribution of slag particles to the workability overwhelms the side-effect of decreased potential of saturated multiple cracking.

Comparison of Cleaning Performance of CFC 113 and the Alternatives (CFC 113과 대체세정제의 세정성능 비교)

  • Row, Kyung Ho;Choi, Dai-Ki;Lee, Youn Yong
    • Analytical Science and Technology
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    • v.6 no.5
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    • pp.521-530
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    • 1993
  • According to the Montreal Protocol, CFC 113, one of the ozone-depleting substances, will be prohibited to use as a cleaning solvent essentially in the electronic industry. Therefore, the development of the alternative cleaning solvents to CFC 113 is being accelerated. A number of the alternative cleaning solvents are avialable on the market. The alternatives of Axarel 32(DuPont), Cleanthru 750H(KAO Chemical), and EC-Ultra(Petroferm) are chosen for the comparison of cleaning performance with CFC 113. The test methods for measuring the cleaning performance were composed of the measurement of the physical properties, the experiments on the material compatibility with cleaning solvents, the measurement of the evaporation rate, and finally the experiments of the removal efficiency. Normally the basic physical properties of the alternatives had higher boiling points, viscosity and surface tension, which were quite different to those of CFC 113. In terms of solubility of rosin-based flux, the solubilities of abietic acid (nonpolar organic) were similar, but those of the activator (polar organic) in the alternatives were better than CFC 113. The evaporation of the alternatives was very slow, compared to CFC 113, which had much lower boiling point. All the cleaning solvents showed the good material compatibility with FR4 and Cu-coated PCB. The better removal efficiencies of abietic acid were obtained when using the ultrasonic mechanical energy over the dipping method. The experiments also indicated the very slow-eavaporating solvent was not desirable with the dipping cleaning method, and the differences in the removal efficiency of the alternatives with the ultrasonic cleaning method were negligible. Among the alternatives, the overall cleaning performances were obsorved as almost similar. Before selecting the ultimate cleaning solvent, the application of cleaning machine, environmental issues, and economics are simultaneously considered with the cleaning performance.

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A Study on the Material Characteristics and Functionality Evaluation of a Size Layer of a Canvas (캔버스 차단층(Size Layer)의 재료특성 및 기능평가 연구)

  • Kim, Hwan Ju;Lee, Hwa Soo;Chung, Yong Jae
    • Journal of Conservation Science
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    • v.32 no.2
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    • pp.167-178
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    • 2016
  • Despite the size layer is an important part for conserving the artworks in the configuration of oil painting, the conservation scientific approaches of that have not been made yet. Therefore, this study produced standard samples on the basis of the analysis results of oil painting works, and carried out the evaluation of functions of the size layer materials. As a result of literature material, traditionally, animal glue was used for the size layer, whereas synthetic resin have been used in combination with animal glue since the modern age, in particular, it was identified that Polyvinyl Acetate(PVAc) was in general use. As a result of analysis of oil painting works, size layer was detected on the support and it was identified as animal glue. As a result of analysis based on Funaoka canvas for ground, it showed that the lead oxide and the titanium dioxide were the main constituents. On the basis of these results, standard samples were produced. As a result of evaluation on the functions of the size layer materials, in the case of the animal glue, stable result was observed in the shrinkag expansion rate, whereas slight weakness was observed in moisture proofing, color, and tensile strength, and dense cracks were found on surface. As for PVAc(A), moisture proofing, color, and the tensile strength exhibited stable results. Higher shrinkage rate was observed and the cracks with wide gaps were found on surface. As for PVAc(B), tensile strength, shrinkage expansion rate, and surface observation showed stable results, whereas moisture proofing property showed poor results. Different aspects were observed in each experiment, and this phenomena were considered to be due to the density and the adhesion properties between the hydrophilic and hydrophobic molecules in the size layer materials. The results are expected to be used as materials for the oil painting work conservation henceforth.

Development of Immediate Face Lifting Technology for Reducing Wrinkles by Using Film-Forming Agent (피막 형성제를 이용한 즉각 리프팅 기술 개발)

  • Jun, Ji hyun;Ko, Eun ah;Han, Sang Gun;Kang, Hakhee
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.44 no.3
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    • pp.211-218
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    • 2018
  • Instant face lifting cosmetics contain various film forming agents for stretching the wrinkles on the skin surface. But, most of the film-forming polymers have sticky feels. And they are easily scrubbed out when skin is rubbed on. In this study, we focused on the influence of sodium silicate that has rapid film forming effect on skin surface and immediate wrinkle reducing effect. Sodium silicate, also known as water glass or soluble glass, is a compound containing sodium oxide and silica. Sodium silicate is a white powder that is readily soluble in water, producing an alkaline solution. Sodium silicate is stable in neutral and alkaline solutions. The sodium silicate solution hardens by drying in air and rapidly forms a thin film. When the solution is applied to the skin, the fine membrane coating is formed by water evaporation and ionic bond re-formation. It also makes the strong siloxane (Si-O) bonding on the skin surface. When these fixation properties are applied to cosmetics, they can give remarkable skin tightening effect. The sodium silicate solution can provide the lifting effect by forming a film on skin at a proper concentration. But, skin irritation may be caused with too high concentration of sodium silicate. We studied a desirable range of the sodium silicate concentration and combination with other fixatives for skin care formulation that has no sticky feels and no scrubbing out phenomenon. Immediate lifting gel was developed by using sodium silicate and various thickening systems. Among of the various thickeners, aluminum magnesium silicate showed the best compatibility with sodium silicate for rapid lifting effect. This instant physical lifting gel was confirmed as a low stimulating formula by skin clinical test.

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.

A Study on Formulation Optimization for Improving Skin Absorption of Glabridin-Containing Nanoemulsion Using Response Surface Methodology (반응표면분석법을 활용한 Glabridin 함유 나노에멀젼의 피부흡수 향상을 위한 제형 최적화 연구)

  • Se-Yeon Kim;Won Hyung Kim;Kyung-Sup Yoon
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.49 no.3
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    • pp.231-245
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    • 2023
  • In the cosmetics industry, it is important to develop new materials for functional cosmetics such as whitening, wrinkles, anti-oxidation, and anti-aging, as well as technology to increase absorption when applied to the skin. Therefore, in this study, we tried to optimize the nanoemulsion formulation by utilizing response surface methodology (RSM), an experimental design method. A nanoemulsion was prepared by a high-pressure emulsification method using Glabridin as an active ingredient, and finally, the optimized skin absorption rate of the nanoemulsion was evaluated. Nanoemulsions were prepared by varying the surfactant content, cholesterol content, oil content, polyol content, high-pressure homogenization pressure, and cycling number of high-pressure homogenization as RSM factors. Among them, surfactant content, oil content, high-pressure homogenization pressure, and cycling number of high-pressure homogenization, which are factors that have the greatest influence on particle size, were used as independent variables, and particle size and skin absorption rate of nanoemulsion were used as response variables. A total of 29 experiments were conducted at random, including 5 repetitions of the center point, and the particle size and skin absorption of the prepared nanoemulsion were measured. Based on the results, the formulation with the minimum particle size and maximum skin absorption was optimized, and the surfactant content of 5.0 wt%, oil content of 2.0 wt%, high-pressure homogenization pressure of 1,000 bar, and the cycling number of high-pressure homogenization of 4 pass were derived as the optimal conditions. As the physical properties of the nanoemulsion prepared under optimal conditions, the particle size was 111.6 ± 0.2 nm, the PDI was 0.247 ± 0.014, and the zeta potential was -56.7 ± 1.2 mV. The skin absorption rate of the nanoemulsion was compared with emulsion as a control. As a result of the nanoemulsion and general emulsion skin absorption test, the cumulative absorption of the nanoemulsion was 79.53 ± 0.23%, and the cumulative absorption of the emulsion as a control was 66.54 ± 1.45% after 24 h, which was 13% higher than the emulsion.

Experimental Study on Long-term Characteristics of Sprayable Waterproofing Membrane (차수용 박층 멤브레인의 장기 성능 변화에 관한 실험 연구)

  • Choi, Soon-Wook;Kim, Jintae;Choi, Myung-Sik;Chang, Soo-Ho;Kang, Tae-Ho;Lee, Chulho
    • Journal of the Korean Geosynthetics Society
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    • v.18 no.4
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    • pp.15-23
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    • 2019
  • The sprayable waterproofing membrane is a recently introduced material in the civil engineering field, and is a material that sprays and attaches a single phase or two phase powder or liquid material to a surface to be covered using a pump and nozzle. Although the material properties are gradually reported through researches, there is a lack of studies on long-term performance compared to concrete materials used with the membranes. In this study, the long-term performance of materials was estimated using the Arrhenius equation. The temperature conditions used in this study were 65℃, 80℃ and 95℃, and the temperature was maintained with the membrane attached to the concrete block for long-term behavior. Then the membranes were tested for tensile strength and adhesion strength in the order of 30, 90, 150, 200, and 300 days. The long-term performance of the material was determined from a long-term perspective by estimating the activation energy by the Arrhenius equation. Consequently, the time to reach 50% of the performance standard could be estimated by long-term test.

A Study on Catalytic Activity of Oxygen Reduction Reaction and Performance of PEMFC using Pt/C Synthesized by Modified Polyol (수정된 폴리올법으로 합성된 Pt/C를 이용한 산소환원반응성 및 고분자전해질 연료전지 성능 연구)

  • Yang, Jongwon;Chu, Cheonho;Kwon, Yongchai
    • Journal of Energy Engineering
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    • v.23 no.3
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    • pp.157-162
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    • 2014
  • In this research, we investigate electrical performance and electrochemical properties of carbon supported Pt (Pt/C) that is synthesized by polyol method. With the Polyol_Pt/C that is adopted for oxygen reduction reaction (ORR) as cathode of proton exchange membrane fuel cells (PEMFCs), their catalytic activity and ORR performance and electrical performance are estimated and compared with commercial Pt/C(Johnson Mattey) catalyst. Their electrochemically active surface (EAS) area are measured by cyclic voltammetry (CV), respectively. On the other hand, regarding ORR activity and electrical performance of the catalysts, (i) linear sweeping voltammetry by rotating disk electrode and (ii) PEMFC single cell tests are used. The CV measurement demonstrate EAS of Polyol_Pt/C is compared with commercial JM_Pt/C. In case of Polyol_Pt/C, its half-wave potential, kinetic current density are excellent. Based on data obtained by half-cell test, when PEMFC single cell tests are carried out, current density measured at 0.6V and maximum power density of the PEMFC single cell employing Polyol_Pt/C are better than those employing commercial Pt/C. Conclusively, Polyol_Pt/C synthesized by modified polyol process shows better ORR catalytic activity and PEMFC performance than other catalysts.

Spatting and Fire Enduring Properties of High Strength RC Column Subjected to Axial Load Depending on Fiber Contents (중심 축하중을 받는 고강도 RC기둥의 섬유 혼입량에 따른 폭열 및 내화 성상)

  • Han, Cheon-Goo;Hwang, Yin-Seong;Lee, Jae-Sam;Kim, Kyoung-Min
    • Journal of the Korea Concrete Institute
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    • v.18 no.1 s.91
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    • pp.83-90
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    • 2006
  • This paper investigates experimentally the fire resistance performance and spatting resistance of high performance reinforced concrete column member subjected to fire containing polypropylene fiber(PP fiber) and cellulose fiber(CL fiber). An increase in PP fiber and CL fiber contents, respectively resulted in a reduction of fluidity due to fiber ball effect. Air content is constant with m increase in fiber content. Compressive strength reached beyond 50 MPa. Based on fire resistance test, severe failure occurred with control concrete specimen, which caused exposure of reinforcing bar. No spall occurred with specimen containing PP fiber. This is due to the discharge of internal vapour pressure. Use of CL fiber superior to control concrete in the side of spatting resistance, localized failure at comer of specimen was observed. Corner of specimen had deeper neutralization than surface of specimen. Specimen containing PP fiber had the least damaged area due to spatting. Neutralization depth ranged between 6 and 8 mm Residual compressive strength of specimen containing PP fiber maintained 40%, which is larger than control concrete with 20% of residual strength. Specimen containing CL fiber had 25% or residual strength.