• Journal of the Korean Wood Science and Technology
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• v.47 no.1
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• pp.40-50
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• 2019

The aim of this study was to investigate the effects of density, temperature, size, and grain direction on measurement of moisture contents (MC) of wood materials non-destructively. The MC of different sizes of solid wood, glulam, and CLT from larch (larix kaempferi, $560kg/m^3$) and pine (pinus koraiensis, $430kg/m^3$) were measured using the dielectric type and resistance type meters. The specimens were conditioned in the environmental chamber to be equilibrium moisture content (EMC) of 12 % and 19 %. When density setting in dielectric type meter was increased from $400kg/m^3$ to $600kg/m^3$, the MCs of specimen (S-L-100-E) were decreased from 13.4 % to 11.3 %. However, when wood group (WG) setting in resistance type meter was changed from WG1 to WG4, the measured MCs were increased from 9.2 % to 12.3 %. When temperature setting in resistance type meters was changed from 0 to $35^{\circ}C$, the MC was decreased from 17.0 % to 13.0 %. The MCs measured by dielectric type meter for larger specimens (S-L-100-E_11.3 %, G-L-240-E_11.7 % and C-L-120-E_12.8 %) were higher than those of small size specimens (S-L-30-E_8.7 %, G-L-150-E_10.3 %, and C-L-90-E_9.7 %). The MCs measured by resistance type meter for larger specimens (G-L-240-E_11.6 % and C-L-120-E_13.3 %) were also higher than those of small size specimens (G-L-150-E_10.4 %, and C-L-90-E_11.8 %). The resistance type meter was not affected by the grain direction but the dielectric type meter were affected by the grain direction. The MC measured by resistance type meter for G-L-120-E perpendicular to grain direction was 11.5 % and the measured MC parallel to grain direction was 11.3 %. The MC measured by dielectric type meter parallel to grain direction (12.1 %) was higher than that measured perpendicular to grain direction (10.7 %).

• Journal of the Korean Wood Science and Technology
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• v.40 no.4
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• pp.287-293
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• 2012

This study was carried out in order to compare nail shear strength between domestic plywood and imported OSB for structural sheathing members as infill wall of wooden construction. The differences of nail shear strength between parallel-to-grain direction and perpendicular-to-grain direction of sheathing material to frame material were distinct at the plywood composition. The shear strengths of plywood and OSB with nail met current design values. The plywood of P-4 type, which uses MLH at surface layer and constructs 7 ply, showed greater than OSB regardless of grain direction of sheathing material to frame material. When the plywood as sheathing material to frame material was used, it was found out that the overall construction of perpendicular-to-grain direction of plywood had greater nail shear strengths than the construction of parallel-to-grain.

• Journal of the Korean Society of Safety
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• v.33 no.1
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• pp.1-6
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• 2018

The effects of the fiber direction, specimen size and temperature on the compressive strength of carbon fiber reinforced silicon carbide composite (C/SiC composite) manufactured by liquid silicon infiltration(LSI) is investigated. Tests were conducted in accordance with ASTM C 695 at room temperature and elevated temperatures. Experiments are conducted with two different specimens considering grain direction. With grain (W/G) specimens have a carbon fibers parallel to the load direction, but across grain (A/G) specimens have a perpendicular carbon fibers. To verify the specimen size effect of C/SiC composite, two types of specimens are manufactured. One has a one to two ratio of diameter to height and the other has a one to one ratio. The compressive strength of C/SiC composite increased as temperature rise. As specimens are larger, compressive strength of A/G specimens increased, however compressive strength of W/G decreased.

• Journal of the Korean Wood Science and Technology
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• v.26 no.1
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• pp.87-96
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• 1998

The bending performances were evaluated at the radiata pine plywood through veneer compositions encompassing veneer quality, ply-numbers and overlays of the high density- or medium density-phenol resin impregnated sheets (hereafter abbreviated as resin sheets) on the raw plywood. In addition, a prediction on the bending MOE of veneers and plywoods was carried out by the nondestructive testing with stresswave timer. The summarized results were as follows: I. Bending strength and bending MOE of resin sheets-overlaid plywoods in parallel surface grain direction through 5 and 7ply were increased by 13 to 45% and 17 to 34%, respectively. Resin sheets-overlay occurred an increasing effect of the strength efficiency i.e. strength perpendicular-to-grain direction versus that parallel-to-grain direction, showing the phenomenon that the plywood strength becomes greater at the perpendicular-to-grain direction of 7ply than at that of 5ply. Displacement at bending failure had a greater trend at 7ply than at 5ply, and was decreased by resin sheets-overlay. 2. After the nondestructive bending MOEs were measured for individual veneers, these veneers were rearranged in plywood-manufacture. In these plywoods, including resin sheets-overlay, the actual MOE was predictable with feasibility of $R^2$=0.53, and also the nondestructively-evaluated MOE was lower by 20% in raw plywood, and higher 20% in LVL than actual bending MOEs.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.5
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• pp.250-257
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• 2006

It is well known that Grain-oriented electrical steel sheets have two dimensional magnetic properties according to the direction of exciting field such as non-linear phase difference between magnetic flux density and magnetic field intensity vectors, different iron loss and permeability even when an alternating magnetic field is applied. The measurement and application of the two dimensional magnetic properties of the Grain-oriented electrical steel sheets, therefore, are very important for the design and precise performance analysis of electric machines made of them. As the direction of exciting field changes, in this paper, the two dimensional magnetic properties of a Grain-oriented electrical steel sheet, i.e., non-linear B-H curves, phase difference between B and H, and iron loss characteristics, are measured using SST(Single Sheet Tester) which has two axes excitation. The measured results are presented in two ways: using $(B,\theta_B)$ method and using hysteresis loops along rolling and transverse directions, respectively.

• Korean Journal of Materials Research
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• v.31 no.7
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• pp.397-402
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• 2021

In this study, binderless-WC, WC-6 wt%Co, WC-6wt% 1 and 2.5 B₄C materials are fabricated by spark plasma sintering process (SPS process). Each fabricated WC material is almost completely dense, with a relative density up to 99.5 % after the simultaneous application of pressure of 60 MPa. The WC added Co and Co-B₄C materials resulted in crystalline growth. The WC with HCP crystal structure has respective interfacial energy (basal facet direction: 1.07 ~ 1.34 J·m^-2, prismatic direction: 1.43 ~ 3.02 J·m^-2) that depends on the grain growth direction. It is confirmed that the continuous grain growth, biased by the basal facet, which has relatively low energy, is promoted at the WC/Co interface. As abnormal grain growth takes place, the grain size increases more than twice from 0.37 to 0.8 um. It is found through analysis that the hardness property also greatly decreases from about 2661.4 to 1721.4 kg/mm², along with the grain growth.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.4
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• pp.44-50
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• 1998

The creep life fraction can be evaluated by the degree of grain deformation since the grain of Cr-Mo base metal deforms in the direction of stress. The grain deformation method using image processing technique is developed for life assessment of in-service high-temperature components. The new assessment model of grain deformation method is presented to apply to in-service components and is verified by interrupted creep test for ex-serviced material of 1Cr-0.5Mo steel. The proposed model, which is irrespective of stress direction, is to evaluate mean of the absolute deviation for the measured ratios which are diametrical maximum to minimum dimensions for grains.

• Journal of the Korean Wood Science and Technology
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• v.41 no.2
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• pp.100-104
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• 2013

Bearing occurs by the rotations of members induced from horizontal or vertical load at traditional wooden joint in frame. The bearing between wooden members is not occurring at the whole surface of joint, but occurring only at the particular bearing area. In this study, partial bearing according to the different grain direction was evaluated. The partial compressive strength showed 3 times higher than pure compressive strength perpendicular to grain, 1.5 times higher than parallel to grain and 3.3 times higher than both of them. It is expected that this result can be very importantly applied when evaluating and analyzing the actual behavior of traditional wooden mortise and tenon joint.

• Journal of the Korean Society for Heat Treatment
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• v.16 no.4
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• pp.197-204
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• 2003

Honeycomb structure has been fabricated by brazing method using 0.1 wt%C and 1.0wt%C carbon steel core and STS304 stainless steel face sheet. Core shear strength ratio in W and L directions was 1:1.03 in 7 mm cell size, whereas 1:1.45 in 4 mm cell size. Flexural strength on face sheet was 166.4 MPa (0.1 wt%C, W direction), 171.1 MPa (0.1 wt%C, L direction), and 120.2 MPa (1.0 wt%C, W direction) in 7 mm cell size. And in 4mm cell size specimen, it was 169.2 MPa (0.1 wt%C, W direction), 224.2 MPa (0.1 wt%C, L direction). This means that flexural strength of 0.1 wt%C core material was higher than that of 1.0wt%C core material, which was contrary to expectation. SEM and EDS analysis represented that grain boundary diffusion had occurred in0.1 wt%C core, but no grain boundary diffusion in 1.0 wt%C core. And corrugated surface of 0.1 wt%C core was flat, whereas that of 1.0 wt%C core was not flat. As a result, contact area between two 1.0 wt%C cores was much less than that of 0.1 wt% cores, It is thought to be main reason for lower flexural strength of 1.0 wt%C core.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.237-240
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• 2003

This paper reports the characteristics of TFTs, formed inside a location-controlled grain: "single-crystalline" Si TFTs (c-Si TFTs). Position of the grains were controlled with a great precision by "${\mu}-Czochralski$ (grain-filter) process". Effects of process parameters, such as, deposition method of gate $SiO_2$, crystallization energy density and position of the channel with respect to the grain filters on TFT characteristics is investigated. It is concluded that the characteristics of TFTs drastically improved by avoiding the grain filter from the channel region. With TFTs having the current-flow direction parallel to radial direction from the grain-filter, electron mobility and subthreshold swing of 600 $cm^2/Vs$ and 0.21 V/dec. respectively are obtained.