• Journal of the Korea Convergence Society
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• v.11 no.8
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• pp.223-228
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• 2020

The need to steadily manage healthy hair for a beautiful hairstyle is emerging, and it is time to develop hair cosmetics using natural antioxidants that are harmless to the human body according to the needs of the times. Therefore Max. Load, Max. Stress, Max. Elongation, and breakage on the hair coated with the extract of Ginkgo biloba L. According to the Break Load, Break Stress, Break Elongation, Max. Various convergence property experiments such as modulus and Tangential modulus values were conducted. As a result of research, the hairs coated with Ginkgo biloba extract had an overall increase in intrinsic properties including tensile strength compared to the control group. Through this study, we intend to study the potential of Ginkgo biloba L. as a useful material for hair cosmetics such as permanent wave preparations as well as health supplements and medicines that have been released, and we expect that it will be provided as useful research data for the subsequent development of various hair cosmetics.

• Food Engineering Progress
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• v.15 no.4
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• pp.305-310
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• 2011

Edible films were developed from defatted soybean meal (DSM), a byproduct from the soy product industry, investigating the effects of the concentrations of DSM and glycerol and the treatment of high pressure homogenization (HPH) on color, water vapor permeability, and tensile properties of the films. The physical properties of the developed films (DSM films) were compared to those of the films made of soy proteins isolated from the DSM. DSM films were obtained by drying film-forming solutions prepared with DSM powder, glycerol, and water and with and without HPH at 152 MPa. HPH resulted in the formation of continuous and uniform films. Water vapor permeability of the films increased with increase in the concentration of glycerol and decreased by high pressure homogenization. The increase in the glycerol concentration in the film-forming solution prepared without HPH decreased the tensile strength and elastic modulus of the films. However, this effect was not observed with the HPH-treated solution. DSM films possessed higher tensile strength and percentage elongation than the film of soy protein, implying the potential for the DSM film to be applied to food product as an edible film.

• Polymer(Korea)
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• v.26 no.1
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• pp.145-151
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• 2002

Thermoplastic starch(TPS) was prepared from mixing starch and glycerol by twin extruder. The blends were then prepared from high density polyethylene(HDPE) and TPS. Mechanical properties, thermal properties, and morphology of the blends were investigated. Their biodegradability was also studied by using aerobic composting method(ISO14855). Tensile strength, modulus and elongation at break decreased as the content of TPS increased. In particular elongation at break decreased rapidly even at the lower content of TPS. The melting temperatures of the blends were not changed, which showed that HDPE and TPS were immiscible. The morphology of the fractured surface of blend films was investigated by scanning electron microscopy(SEM). It was found that phases were separated. After composting for 45days, the biodegradability of the blends increased as the content of TPS increased.

• Advances in concrete construction
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• v.4 no.1
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• pp.49-69
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• 2016

This work investigates the mechanical properties of conventional concrete (CC) and self compacting concrete (SCC) using fine rubber and silpozz were accompanied by a comparative study between conventional rubberized concrete (CRC) and self compacting rubberized concrete (SCRC). Fine rubber (FR) from scrap tires has replaced the fine aggregate (FA) and Silpozz has been used as a replacement of cement at the proportions of 5, 10 and 15%. Silpozz as a partial replacement of cement in addition of superplasticiser (SP) increases the strength of concrete. Fresh concrete properties such as slump test, compaction factor test for CRC, whereas for SCRC slump flow, $T_{500}$, V-funnel, L-box, U-box, J-ring tests were conducted along with the hardened properties tests like compressive, split tensile and flexural strength test at 7, 28 and 90 days of curing. The durability and microstructural behavior for both CRC and SCRC were investigated. FR used in the present study is 4.75 mm passing with fineness modulus 4.74.M30 grade concrete is used with a mix proportion of 1:1.44:2.91 and w/c ratio as 0.43. The results indicate that as FR quantity increases, workability of both CRC and SCRC decreases. The results also show that the replacement of natural fine aggregate (NFA) with FR particles decreases the compressive strength with the increase of flexural strength observed upto 5% replacement of FR. Also replacement of cement with silpozz resulted enhancement of strength in SCRC.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.252-257
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• 2004

Nanometer-sized structures are being applied to many devices including micro/nano electronics, optoelectronics, quantum devices, MEMS/NEMS, biosensors, etc. Especially, the thin film with submicron thickness is a basic structure for fabricating these devices, but its mechanical behaviors are not well understood. The mechanical properties of the thin film are different from those of the bulk structure and are difficult to measure because of its handling inconvenience. Several techniques have been applied to mechanical characterization of the thin film, such as nanoindentation test, micro/nano tensile test, strip bending test, etc. In this study, we focus on the strip bending test because of its high accuracy and moderate specimen preparation efforts, and measure Au thin film, which is a very popular material in micro/nano electronic devices. Au film is deposited on Si substrate by evaporation process, of which thickness is 100nm. Using the strip bending test, we obtain elastic modulus, yield and ultimate tensile strength, and residual stress of Au thin film.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.361.1-361.1
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• 2016

Due to their high sensitivity, fast response, small energy consumption and ease of integration, nanoelectromechanical systems (NEMS) have attracted much interest in various applications such as high speed memory devices, energy harvesting devices, frequency tunable RF receivers, and ultra sensitive mass sensors. Since the device performance of NEMS is closely related with the mechanical and flexural properties of the material in NEMS, analysis of the mechanical and flexural properties such as intrinsic tensile stress and Young's modulus is a crucial factor for designing the NEMS structures. In the present work, the intrinsic mechanical properties of highly stressed silicon nitride (SiN) beams are investigated as a function of the beam length using two different techniques: (i) dynamic flexural measurement using optical interferometry and (ii) quasi-static flexural measurement using atomic force microscopy. The reliability of the results is analysed by comparing the results from the two different measurement techniques. In addition, the mass density, Young's modulus and internal stress of the SiN beams are estimated by combining the techniques, and the prospect of SiN based NEMS for application in high sensitive mass sensors is discussed.

• The korean journal of orthodontics
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• v.48 no.5
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• pp.316-325
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• 2018

Objective: The aim of this systematic multiscale analysis was to evaluate the effects of thermoforming on the physical and mechanical properties of thermoplastic materials used to fabricate transparent orthodontic aligners (TOAs). Methods: Specimens were fabricated using four types of thermoplastic materials with different thicknesses under a thermal vacuum. Transparency, water absorption and solubility, surface hardness, and the results of three-point bending and tensile tests were evaluated before and after thermoforming. Data were analyzed using one-way analysis of variance and Student's t-test. Results: After thermoforming, the transparency of Duran and Essix A+ decreased, while the water absorption ability of all materials; the water solubility of Duran, Essix A+, and Essix ACE; and the surface hardness of Duran and Essix A+ increased. The flexure modulus for the 0.5-mm-thick Duran, Essix A+, and eCligner specimens increased, whereas that for the 0.75-/1.0-mm-thick Duran and eClginer specimens decreased. In addition, the elastic modulus increased for the 0.5-mm-thick Essix A+ specimens and decreased for the 0.75-mm-thick Duran and Essix ACE and the 1.0-mm-thick Essix ACE specimens. Conclusions: Our findings suggest that the physical and mechanical properties of thermoplastic materials used for the fabrication of TOAs should be evaluated after thermoforming in order to characterize their properties for clinical application.

• Food Science and Biotechnology
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• v.18 no.4
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• pp.910-916
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• 2009

Present work was focused on the influence of methylcellulose (MC) on steady rheology of wheat gliadin solution and the properties of glycerol plasticized gliadin films. The presence of MC below 0.99 wt% improved viscosity and flow activation energy of the 10 wt% gliadin solution significantly. In the casting films containing 0.2 g glycerol/g dry protein, the MC component aggregated in the gliadin matrix. The blend films containing less than 7.7 wt% MC exhibited higher Young's modulus (E) and tensile strength (${\sigma}_b$) and lower elongation at break (${\epsilon}_b$) in comparison with the pure gliadin film, which was related to the intermolecular interaction between MC and gliadins, the brittle fracture of the aggregated MC component, and the increase in glass transition temperature ($T_g$) of the gliadin phase. Increasing MC content led to a slight increase in water vapor permeability (WVP) without significant influence on the moisture absorption (MA).

• Journal of the Korea Concrete Institute
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• v.12 no.5
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• pp.131-139
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• 2000

Porous Concrete usually contains large amount of voids(about 10∼20%) after compaction so that it has relatively high permeability. It has been introduced in domestic since early 1980's but it has problems such as lack of optimized mixture, low strength and durability, and other defects, etc. The purpose of this study is to manufacture high-performance porous concrete using polymer to enhance the mechanical properties. The results of this study are as follows; the compressive strength range 12 92∼207kgf/㎠, the tensile strength range is 14∼28kgf/㎠, the bending stength range is 42∼73kgf/㎠, and the coefficient permeability range is 5.77×10-2∼6.79×10-1cm/sec. To develope high-performance porous concrete. further studies are needed on optimum mixture of fineness modulus and admixture.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10b
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• pp.1063-1068
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• 2000

Latex modified concrete (LMC) has grown to be accepted as a standard material of construction overlaying bridge decks in America due to its superior physical and chemical properties. The properties of latex, combined with the low water-cement ratio, produce a concrete that has improved flexural, tensile, and bond strength, lower modulus of elasticity, increased freeze-thaw resistance, and reduced permeability compared to conventional concrete of similar mix design. LMC overlays have been service in excellence for 30 years on thousands of bridge in U.S.A. This may, also, prolong the life cycle of bridge deck once it is adopted in Korea. The self-contained, mobile, continuous mixer is most appropriate particularly for concrete quality assurance. Assuring quality on a bridge deck overlay project should begin in the design phase and continue after the construction is completed. Quality should be the concern of everyone involved-owner, designer, and contractor.