• Journal of the Korean Solar Energy Society
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• v.27 no.3
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• pp.169-174
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• 2007

Building integrated photovoltaic(BIPV) system operates as a multi-functional building construction material. They not only produce electricity, but also are building integral components such as facade, roof, window and shading device. As PV modules function like building envelope in BIPV, combined thermal and PV performance should be simultaneously evaluated. This study is to establish basic Information for designing effective BIPV by discovering relations between temperature and generation capability through experiment when the PV module is used as roof material for houses. To do so, we established 3kW full scale mock-up model with real size house and attached an PV array by cutting in half. This is to assess temperature influence depending on whether there is a ventilation on the rear side of PV module or not.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.801-806
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• 2008

The best plan is that the insulation performance should be improved because the insulation and airtight of building envelopes have an effect on the energy consumption basically. New insulation materials, which have the high performance and are above insulation standard, have been developed steadily. Because there are not studies on the building energy rating system and economic evaluation considering new insulation materials, these matters should be studied. In result alternatives, which applied 6 high performance material each, influence, reduce the annual heating energy and raise the building energy rating. Applying the vacuum insulation material(Case1,2) and vacuum or triple glazing can retrieves the investment with $120 and $$140{\sim}150$ per barrel each.

• Structural Engineering and Mechanics
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• v.56 no.6
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• pp.917-938
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• 2015

The nonlinear numerical analysis of the impact response of reinforced concrete/mortar beam incorporated with the updated Lagrangian method, namely the Smoothed Particle Hydrodynamics (SPH) is carried out in this study. The analysis includes the simulation of the effects of high mass low velocity impact load falling on beam structures. Three material models to describe the localized failure of structural elements are: (1) linear pressure-sensitive yield criteria (Drucker-Prager type) in the pre-peak regime for the concrete/mortar meanwhile, the shear strain energy criterion (Von Mises) is applied for the steel reinforcement (2) nonlinear hardening law by means of modified linear Drucker-Prager envelope by employing the plane cap surface to simulate the irreversible plastic behavior of concrete/mortar (3) implementation of linear and nonlinear softening in tension and compression regions, respectively, to express the complex behavior of concrete material during short time loading condition. Validation upon existing experimental test results is conducted, from which the impact behavior of concrete beams are best described using the SPH model adopting an average velocity and erosion algorithm, where instability in terms of numerical fragmentation is reduced considerably.

• Korean Journal of Materials Research
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• v.31 no.8
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• pp.450-457
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• 2021

From measured thermal conductivity and modeling by simulation, this study suggests that U-factors are highly related to materials used between steel and polymer. The objective and prospective point of this study are to relate the relationship between the U-factor and the thermal conductivity of the materials used. For the characterization, EDX, SEM, a thermal conductive meter, and computer simulation utility are used to analyze the elemental, surface structural properties, and U-factor with a simulation of the used material between steel and polymer. This study set out to divide the curtain wall system that makes up the envelope into an aluminum frame section and entrance frame section and interpret their thermal performance with U-factors. Based on the U-factor thermal analysis results, the target curtain wall system is divided into fix and vent types. The glass is 24 mm double glazing (6 mm common glass +12 mm Argon +6 mm Low E). The same U-factor of 1.45 W/m²·K is applied. The interpretation results show that the U-factor and total U-value of the aluminum frame section are 1.449 and 2.343 W/m²·K, respectively. Meanwhile, those of the entrance frame section are 1.449 and 2.

• Journal of the Korean institute of surface engineering
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• v.55 no.6
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• pp.398-402
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• 2022

Vacuum Insulation Panel (VIP) is an high energy efficient insulation system that facilitate slim but high insulation performance, based on based on a porous core material evacuated and encapsulated in a multi-barrier envelope. Although VIP has been on the market for decades now, it wasn't until recently that efforts have been initiated to propose a standard on aging testing. One of the issues regarding VIP is its durability and aging due to pressure and moisture dependent increase of the initial low thermal conductivity with time. It is hard to visually determine at an early stage. Recently, a method of analyzing the damage on the a material surface by applying image processing technology has been widely used. These techniques provide fast and accurate data with a non-destructive way. In this study, the surface VIP images were analyzed using the Harris corner detection algorithm. As a result, 171,333 corner points in the normal packaging were detected, whereas 32,895 of the defective packaging, which were less than the normal packaging. were detected. These results are considered to provide meaningful information for the determination of VIP condition.

• Journal of the Korean Wood Science and Technology
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• v.30 no.3
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• pp.97-103
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• 2002

This study was carried out to obtain basic information on racking resistance of shear walls and the factors affecting racking resistance of shear walls. Shear walls constructed by larch lumber nominal 50 mm × 100 mm framing and various sheathing materials were tested by applying monotonic and cyclic load functions. Shear walls with various stud spacing such as 305 mm, 406 mm, and 610 mm were tested under both of monotonic and cyclic loads and shear walls with various aspect (height-width) ratios were tested under cyclic load functions. The effect of hold-down connectors in shear walls was also tested under cyclic load functions. Racking resistance of shear walls has very close linear relation with stud spacing and width of shear walls. The ultimate racking strength of shear walls was reached at around or before the displacement of 20 mm. It was proposed in this study that the minimum racking strength and minimum width for shear wall be 500 kgf and 900 mm, respectively. Load-displacement curves obtained by racking tests under monotonic load functions can be represented by three straight line segments. Under cyclic load functions, envelope curves can be divided into three sections that can be represented by straight lines and the third section showed almost constant or decreasing slope.

• Journal of the Korean Magnetics Society
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• v.21 no.4
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• pp.136-140
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• 2011

Mechanical properties of degraded materials must be measured for evaluating the integrity of the facilities operating at high temperature. In fact it is complicated to obtain the different degraded specimens from an operating facility. Specimens of 1Cr-0.5Mo steel prepared by the isothermal heat treatment at $700^{\circ}C$ were tested, which has been widely used as tubes for heat exchangers and as plates for pressure vessels. The magnetic properties and Rockwell hardness (HRB) were measured at room temperature. The peak interval of Barkhausen noise envelope (PIBNE), coercivity, and hardness decreased with the increase of degradation. The magnetic and mechanical softening of matrix is likely to govern the properties of the specimen more than the hardening of grain boundary by carbide precipitations. The degradation of test material may be determined by the linear correlation of PIBNE and HRB. Degradation of 1Cr-0.5Mo steel could well be nondestructively evaluated by PIBNE measured with surface type probe.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.47 no.2
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• pp.99-105
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• 2021

This study was conducted to identify the efficacy related to skin barrier functions such as anti-inflammatory, anti-allergic, cornified envelope formation and the alleviation effect of keratinocyte damage caused by S. aureus using the callus extract, which was induced and extracted from the leaves of Gynostemma pentaphyllum in Ulleungdo Island. In order to confirm the anti-inflammatory effect of the G. pentaphyllum callus extract on the skin, the expression of inflammatory cytokines was investigated in primary epidermal keratinocytes (HEKa) activated with PAR-2 agonist, and the G. pentaphyllum callus extract showed IL-8, IL-25, and TSLP production inhibitory effect. β-Hexosaminidase assay using RBL-2H3 cells was performed to confirm the anti-allergic efficacy, and G. pentaphyllum callus extract showed the effect of inhibiting the release of β-hexosaminidase. In addition, G. pentaphyllum callus extract showed the cornified envelope formation effect in HaCaT cells, and through the co-culture experiment with HaCaT cells and S. aureus, it showed alleviation effect of keratinocyte damage caused by S. aureus. Therefore, G. pentaphyllum callus extract is considered to be a useful cosmetic material for improving skin barrier with anti-inflammatory, anti-allergic and alleviation effect of keratinocyte damage caused by S. aureus.

• Structural Engineering and Mechanics
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• v.14 no.4
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• pp.435-454
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• 2002

The paper proposes analytical forms able to represent with very good approximation the constitutive law experimentally deducible by means of uniaxial cyclic compressive tests on material having softening post-peak behaviour in compression and negligible tensile strength. The envelope, unloading and reloading curves characterizing the proposed model adequately approach structural responses corresponding to different levels of nonlinearity and ductility, requiring a not very high number of parameters to be calibrated experimentally. The reliability of the model is shown by comparing the results that it is able to provide with the ones analytically deduced from two reference models (one for concrete, another for masonry) available in the literature, and with experimental results obtained by the authors in the framework of a research in progress.

• Structural Engineering and Mechanics
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• v.62 no.1
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• pp.43-54
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• 2017

In this study, the failure behavior of composite material in the biaxial and off-axis loading is studied based on a computational micromechanical model. The model is developed so that the combination of mechanical and thermal loading conditions can be considered in the analysis. The modified generalized plane strain assumption of the theory of elasticity is used for formulation of the micromechanical modeling of the problem. A truly meshless method is employed to solve the governing equation and predict the distribution of micro-stresses in the selected RVE of composite. The fiber matrix interface is assumed to be perfect until the interface failure occurs. The biaxial and off-axis loading of the SiC/Ti and Kevlar/Epoxy composite is studied. The failure envelopes of SiC/Ti and Kevlar/Epoxy composite in off-axis loading, biaxial transverse-transverse and axial-transverse loading are predicted based on the micromechanical approach. Various failure criteria are considered for fiber, matrix and fiber-matrix interface. Comparison of results with the available results in the litreture shows excellent agreement with experimental studies.