• Journal of Power System Engineering
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• v.20 no.5
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• pp.66-71
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• 2016

The measurements of heat transfer and total friction factors for turbulent flows in the convergent rectangular channels with two opposite in-line ribbed walls are reported. The study has covered three different angled ribs ($30^{\circ}$, $45^{\circ}$ and $60^{\circ}$) and Reynolds number in the range of 22,000 to 75,000. The channel, composing of ten isolated copper sections in the length of test section of 1 m, has the channel convergence ratio of $D_{ho}/D_{hi}=0.67$. The results show that the ribs pointing downstream (${\wedge}-shaped$) is somewhat greater than the ribs pointing upstream (V-shaped) in the dimensionless Nusselt number and total friction factors.

• Korean Journal of Human Ecology
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• v.17 no.2
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• pp.315-333
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• 2008

This study aims at analyzing the characteristics of muscular men's somatotype to develop their clothing pattern. The body sizes of 168 men categorized as the muscular type according to the Somatotype Classification by Sheldon and Heath-Carter, were compared with the 5th Korean body size measurement (KBSM) conducted by SizeKorea in 2003, to analyze the characteristics of muscular men's somatotype. The results are as follows: 1. Compared to the 5th KBSM, the subject's body size is higher in the Chest, Upper Arm, Calf, Hip, and Thigh Circumference, and Thigh Thickness, and Waist Back and Biacromion Length, but lower in the Waist Circumference. 2. The subject group shows the characteristics of a wedge-shaped somatotype which has a broad chest and a slim waist, and of having a back more developed, longer and more curved, compared to the non-muscular men. 3. The study shows the subject group has the characteristics of both the wedged somatotype with wide chest and slim waist, and the X somatotype with projected hips and thighs.

• Journal of the Korean Wood Science and Technology
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• v.24 no.2
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• pp.55-60
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• 1996

Tripitaka Koreana were made during Coryo Dynasty from 1236 to 1251 A.D. Buddhist scriptures were engraved on 81.340 wooden plates. Some plates were varnished with Rhus lacquer, but most of them were uncoated. Macroscopically, most of the plates appeared intact due to the storage in a well-ventilated wooden house. Because, they were irregularly used for printings with ink, it can be assumed that they were repeatedly exposed to ink-water and drying processes. The present were made to examine the changes of wood cell structures occurred during long-term aging deterioration processes in these dry archaeological wooden plates. Light, scanning and transmission electron microscopes were employed for this study. Wedge-shaped cracks and delamilations were found from the lumen side toward the compound middle lamellae and they progressed toward primary or secondary walls. A large amount of hypae in vessels and the degradation of vessel-ray pit walls by the fungal hyphae were observed. When compared to the recent wood, the birefringence of wood fibers was considerably lower or completly disappeared, suggesting the degradation of crystalline cellulose in these wood samples. The degradation of the cell wall could be also revealed the calculation of crystallinity with X-ray diffraction and the size of crystalline region was estimated.

• Journal of the Korean Ceramic Society
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• v.33 no.1
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• pp.56-64
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• 1996

A large amount of papers about the cubic-to-tetragonal phase transition the ferroelectric domain structures of the BaTiO3 were already reported but there exist still some needs to observe the domain behaviors directly. In this study the domain structures of the tinned plates prepared from ta single crystal grown by the TSSG technique were observed using a polarizing microscope TE and X-ray topography. The spatial relation be-tween the orientation states of domains was investigated and the effects of external stresses and electric fields on the behaviors of ferroelectric and ferroelastic domains were studied. All the 90$^{\circ}$walls cut off in the crystal are the wedge shaped lamellar domains and all the straight boundaries in the observed domain patte군 can be interpreted as the head-to-tail 90$^{\circ}$walls. The irregular overlapped boundaries commonly observed by using a polarizing microscope and X-ray topography are complex combinations of well-known 90$^{\circ}$walls and are domain walls were predominant and were stabilized after surface polishing. In the paraelectric phase region the domain walls vanished but the residual surface strain patterns could be seen at the same positions of the stabilized 90$^{\circ}$a-a walls in the tetragonal phase region, These stabilized walls resulted from the surface strain had a memory effect in domain formation during the repeated phase transitions and could notr be affected by an external electtric field.

• Tunnel and Underground Space
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• v.20 no.6
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• pp.446-454
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• 2010

CAES-G/T (Compressed Air Energy Storage - Gas Turbine) power generation is a likely option for the buffer facility stabilizing the fluctuation of the renewable powers, such as wind and solar powers. Considering the geological conditions, the underground CAES facility is most probable if the CAES-G/T generation is planed in Korea. In this kind of facility, a concrete plug is installed to seal the compressed air in the container, so that the selection of the shape and dimension of concrete plug could be a critical design factor. The stability evaluation of two types of plug was carried out by investigating the distribution of the factor of safety in the plugs and the distribution of contact pressure over the contact surface. The analysis result shows that the taper-shaped plug is more structurally stable than the wedge-shaped plug for the given geological condition. Possible separation of the rock-concrete interface around the spring line of the wedge-shaped plug is anticipated, which means the possible leakage of compressed air through the side wall and also means the poor mobilization of frictional resistance on that area.

• Journal of the Korean Society of Propulsion Engineers
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• v.10 no.1
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• pp.23-29
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• 2006

In an annular injection supersonic ejector, the supersonic primary flow is injected along the side wall, therefore a funnel-shaped shock wave is generated by the contraction angle of the mixing chamber. In the present study, we developed a simple funnel shock wave model using 2-D wedge and conical shock wave relations. In result, the secondary flow pressure can be predicted more accurately than using a simple 2-D wedge shock wave model. Through the same analysis, the compression ratio and the adiabatic efficiency according to the entrainment ratio were calculated.

• Computers and Concrete
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• v.19 no.2
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• pp.211-216
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• 2017

Crack on concrete surface allows more rapid penetration of chlorides. Crack width and depth are dominant parameters for chloride behavior, however their effects on chloride penetration are difficult to quantify. In the present work, the previous anisotropic (1-D) model on chloride diffusion in concrete with single crack is improved considering crack shape and roughness. In the previous model, parallel-piped shape was adopted for crack shape in steady-state condition. The previous model with single crack is improved considering wedge shape of crack profile and roughness. For verifying the proposed model, concrete samples for nuclear power plant are prepared and various crack widths are induced 0.0 to 1.2 mm. The chloride diffusion coefficients in steady-state condition are evaluated and compared with simulation results. The proposed model which can handle crack shape and roughness factor is evaluated to decrease chloride diffusion and can provide more reasonable results due to reduced area of crack profile. The roughness effect on diffusion is evaluated to be 10-20% of reduction in chloride diffusion.

• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.2
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• pp.315-323
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• 2015

The weld scallop has been used for joining T-bars. There are a lot of weld scallops in shipbuilding. It is difficult to perform scallop welding due to the inconvenient welding position. This results in many problems such as porosity, slag inclusion, etc. In this study, a new method is devised to remove weld scallops by incorporating a Ceramic Backing Material (CBM). The weld scallop is removed by an elongation of the v groove. In order to insert a CBM into the groove without a weld scallop, a wedge-shaped CBM is developed. The top side of the developed CBM is similar to the shape of a general back bead. The bottom surface has a saw-toothed shape for cutting at a suitable length. This can be attached to the root side of a face plate using adhesive tape, just like a general CBM. Welding experiments in normal and abnormal conditions are carried out and the possibility of burn-through is examined. This CBM's applicability to shipbuilding is verified.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05a
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• pp.13-16
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• 2003

Magnetic and magneto-optical properties of Fe/Pt/Fe, Co/Pd/Co trilayers and also the sandwiches with wedge-shaped magnetic (Fe, Co) and nonmagnetic (Pt, Pd) layers were investigated. The oscillatory behavior of the saturation field $H_{s}$ of the studied trilayers with changing the thickness of the nonmagnetic layer (NML) $t_{NML}$ was revealed. That was explained by the exchange coupling between ferromagnetic layers (FML) through the nonmagnetic spacer. For the first time, oscillations of the transverse Kerr effect (TKE) with changing the Pt- and Pd-wedge thickness were discovered. Period of these oscillations was found to depend on the FML thickness and the photon energy of the incident light. TKE spectra of the examined samples were discovered to modify very strongly with increasing $t_{NML}$. The discovered peculiarities of magneto-optical properties of thin-film systems were explained by a concept of the spin-polarized quantum well states in the pt and Pd layers.

• Geotechnical Engineering
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• v.14 no.3
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• pp.73-94
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• 1998

In the present study, a method of the three-dimensional limit equilibrium stability analysis of shape of the potential failure wedge for the concave-shaped excavation corner is assumed on the basis of the results of the FLACSU program analysis. Estimation of the three-dimensional seepage forces expected to act on the failure wedge is made by solving the three-dimensional continuity equation of flow with appropriate boundary conditions. By using the proposed method of three-dimensional stability analysis of the concave-shaped excavation corner, a parametric study is performed to examine the reinforcement effect of skew soil nailing system, range of the efficient skew angles and seepage effect on the overall stability. Also examined is the effect of an existence of the right-angled excavation corner on three-dimensional deflection behaviors of the convex-shaped skew soil nailing walls. The results of analyses of the convexshaped excavation corner with skew soil nailing system is further included to illustrate the effects of various design parameters for typical patterns of skew nails reinforcement system.