• Structural Engineering and Mechanics
• /
• v.72 no.6
• /
• pp.763-774
• /
• 2019

The main aim of this paper is enhancing design of traditional laminated composite plates subjected to static loads. In this regard, this paper suggests embedding a lightweight porous layer in the middle of laminated composite as the core layer of the resulted sandwich plate. The static responses of the suggested structures with uniform, symmetric and non-symmetric porosity distributions are compared to optimize their design. Using the first order shear deformation theories, the static governing equations of the suggested laminated composite plates with a porous layer (LCPPL) rested on two-parameter foundation are obtained. A finite element method is also utilized to solve the governing equations of LCPPLs. Effects of laminated composite and porosity characteristics as well as geometry dimension, edges' boundary conditions and foundation coefficients on the static deflection and stress distribution of the suggested composite plates have been investigated. The results reveal that the use of core between the layers of laminated composites leads to a sharp reduction in the static deflections of LCPPLs. Furthermore, in compare with perfect cores, the use of porous core between the layers of laminated composite plates can offer a considerable reduction in structural weight without a significant difference in their static responses.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.24 no.7 s.178
• /
• pp.1650-1660
• /
• 2000

Continuous casting process has been adopted increasingly in recent years to save both energy and labor. It has experienced a rapid development in the production of semi-finished steel products, rep lacing the conventional route of ingot casting and rolling. In order to achieve this merit, however, more studies about the mechanism between roll and slab are needed. In this paper, a dynamic bulging in steel cast slabs was simulated by considering the solidification and heat transfer. This study is to prevent internal cracks of a slab in a bending and unbending zone. The value of moving strand shell bulging between two supporting rollers under the ferrostatic pressure and slab-self weight has been calculated in terms of creep and elasto-plasticity. The strain and strain rate distributions in solidified shell undergoing a series of bulging are calculated with working boundary conditions.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.10 no.2
• /
• pp.166-173
• /
• 2002

The wheel bearing hub unit is developed type of wheel bearing unified with the hub parts. It has advantage of reducing the weight and the number of components. And, it also improves uniformity of manufacturing quality, In order to design the wheel bearing hub units, many techniques are used such as load analysis, structure analysis and bearing characteristics analysis and so forth. These techniques need highly accurate load conditions founded on service conditions. In this study, to design the wheel bearing hub units used widespread in passenger cars, the service load was measured through driving tests on the public roads and in the special events. The public roads are classified into highway, intercity road, rural road, urban road, and unpaved road so as to know what the characteristics of the road loads are. The results of the tests showed that the wheel force was relative to the lateral acceleration, and also could be calculated from the lateral acceleration. The lateral acceleration was measured from 0.0G to 0.6G in general driving on the public roads, with different distributions in each road type. In special events, the maximum lateral acceleration was measured from 0.8G to 1.3G.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.17 no.1
• /
• pp.96-104
• /
• 2009

An anatomically detailed elderly human body model is under development. Using the anthropometric database of domestic nation-wide size survey, SizeKorea, a standard size and shape of 50th %tile elderly was constructed. Through the local recruitment process, a male volunteer with 71 years of age, 163cm of height and 63kg of weight has been selected. The exterior (skin) and interior (skeleton and organ) geometries were acquired from whole body 3D laser scan and various medical images such as CT, X-ray, and Ultrasonic of the volunteer. A particular attention has been paid into the combining process of exterior and interior geometries especially for joint articulation positions since they were measured at different postures (sitting vs. supine). A whole ribcage of PMHS which possessed similar anthropometry and age of standard 50th %tile elderly was prepared and dissected for the precise gauge of cortical rib bone thickness distributions. After completing the morphological construction of elderly human body, the finite element modeling will be processed by meshing elements and assigning mechanical properties to various biological tissues which reflect the aging effect.

• Journal of Applied Biological Chemistry
• /
• v.42 no.3
• /
• pp.134-139
• /
• 1999

The distributions of Cd, Cu, and Zn concentration in soil treated with one (1988) or two (1988 and 1993) applications of sewage sludge at rates of 0, 25, 50, and $100Mg\;ha^{-1}$ (dry weight basis) were determined to assess the accumulation and mobility of the heavy metals. The heavy metals accumulated almost entirely in 0 to 15 cm soil depths. Small amounts of the metals moved out of the tillage zone (0-15 cm depth) into the subsoil, but even at the high rate of sewage sludge, little movement of heavy metals occurred below 100 cm depth. The water-extractable Cd, Cu, and Zn concentrations were very low regardless of the rate of sewage sludge application. Availability of metals as determined by DTPA extraction showed the percentage of DTPA-extractable/total concentration increased with sewage sludge application. In the 0-15 cm depth of sewage sludge treated soil, the percentage of DTPA-extractable/total concentration was higher than 46% for Cd, but the value was less than 27% and 17% for Cu and Zn, respectively. The Cd, Cu, and Zn added to this calcareous clay soil by sewage sludge application were not very mobile, and the amount of plant available form was very small.

• Journal of the Korean Ceramic Society
• /
• v.27 no.8
• /
• pp.956-956
• /
• 1990

A nitrogenation of coal ash in the presence of carbon was carried out to examine the effects of reaction temperature, reaction time and carbon composition on the formation of AlN, SiC and Si3N4. Decreasing the particle size increased the formation of AlN and its maximum composition in the product was obtaiend under 1450∼1500℃, 2 hours of reaction time and about 30% of carbon addition(on the basis of sample weight). Compositions of SiC and Si3N4 were distributed to the opposite so that SiC showed a higher composition compared with Si3N4 at a lower temperature, a shorter reaction time and a greater carbon addition.

• KSBB Journal
• /
• v.15 no.6
• /
• pp.635-643
• /
• 2000

To compare the antioxidative activities of fish skin and bovine skin gelatin hydrolysate, gelatin hydrolysates from Alaska pollack and bovine skin were prepared by various enzymatic hydrolysis methods (1st step, Alcalase; 2nd step, pronase E; 3rd step, collagenase) using a continuous three-step membrane reactor. The molecular weight distributions of the 1st, 2nd and 3rd step hydrolysates were 7∼10 kDa, 2∼5 kDa and 0.7∼0.9 kDa, respectively. The antioxidative activity of fish skin gelatin hydrolysate was stronger than that of bovine skin gelatin hydrolysate, and in particular, both of 2nd step hydrolysates showed more antioxidative activity than hydrolysates of any other step. The optimum antioxidative activity concentration of the 2nd step hydeolysates of fish and boving skin were 1% (w/w) in a linoleic acid water-alcohol emulsion. In cultured cells exposed to t-butyl hydroperoxide (t-BHP), the 2nd step hydrolysate of fish skin gelatin delayed cell death most. These results suggest that the antioxidative activity of fish skin gelatin hydrolysate is higher than that of bovine skin gelatin hydrolysate because of their different amino acid contents.

• Fashion & Textile Research Journal
• /
• v.1 no.2
• /
• pp.127-136
• /
• 1999

The purpose of this research was to investigate the difference between perceptions of the nude body and of the clothed body as measured by body cathexis scale. Subjects were 274 college male and female between 20~30 yrs. Data were analyzed by using frequency, T test, cluster analysis, Duncan test by using Spss for window 8.0 PC program. Significant difference were found between mean scores of male and female on the nude body cathexis (NBC) and clothed body cathexis (CBC) Scales for hair texture, hair color, face, face color, shape of head, eye, lips, forehead, back, trunk, waist, bust, leg of shape, chest, hip. On the difference between male and female, significant differences were found between NBC and CBC scales for all body parts except hair texture, face color, ears, eyes, teech. Male had higher satisfaction than female in both body cathexis. The taller men, the higher body satisfaction with face shape, body shape, height in both body cathexis. Before appearence management, the bigger men, the higher body satisfaction with musle, waist, height, chest, body shape in both body cathexis. Male had higher satisfaction than female in both body cathexis. The taller women, the higher body satisfaction with neck, body shape, height in before appearence management. The bigger women, the higher body satisfaction with heights, weight distributions, waist, height in both.

• Membrane and Water Treatment
• /
• v.9 no.4
• /
• pp.205-210
• /
• 2018

In this study, we investigated coagulants such as polyaluminum chloride (PACl) and ferric chloride ($FeCl_3$) and the combination of a coagulant and powdered activated carbon (PAC) for the removal of dissolved organic matter (DOM) from fish processing effluent to reduce membrane fouling in microfiltration. The efficiency of each pretreatment was investigated through analyses of dissolved organic carbon (DOC) and ultraviolet absorbance at 254 nm ($UVA_{254}$). Membrane flux and silt density index (SDI) analyses were performed to evaluate membrane fouling; molecular weight distributions (MWD) and fluorescence excitation-emission matrix (FEEM) spectroscopy were analyzed to assess DOM characteristics. The results demonstrated that $FeCl_3$ exhibited higher DOC and $UVA_{254}$ removals than PACl for food processing effluent and a combination of $FeCl_3$ and PAC provided comparatively better results than simple $FeCl_3$ coagulation for the removal of DOM from fish processing effluent. This study suggests that membrane fouling could be minimized by proper pretreatment of food processing effluent using a combination of coagulation ($FeCl_3$) and adsorption (PAC). Analyses of MWD and FEEM revealed that the combination of $FeCl_3$ and PAC was more efficient at removing hydrophobic and small-sized DOM.

• Journal of Mechanical Science and Technology
• /
• v.15 no.11
• /
• pp.1533-1540
• /
• 2001

A high-temperature sodium stainless steel heat pipe was fabricated and its performance has been investigated. The working fluid was sodium and it was sealed inside a straight tube container made of stainless steel. The amount of sodium occupied approximately 20% of the total volume of the heat pipe and its weight was 65.7gram. The length of a stainless steel container is 1002mm and its outside diameter is 25.4mm. Performance tests were carried out in a room air condition under a free convective environment and the measured temperatures are presented. The start-up behavior of the heat pipe from a frozen state was investigated for various heat input values between 600W and 1205W. In steady state, axial temperature distributions of a heat pipe were measured and its heat transfer rates were estimated in the range of vapor temperature from 50$0^{\circ}C$ to 63$0^{\circ}C$. It is found that there are small temperature differences in the vapor core along the axial direction of a sodium heat pipe for the high operating temperatures. But for the range of low operating temperatures there are large temperature drops along the vapor core region of a sodium heat pipe, because a small vapor pressure drop makes a large temperature drop. The transition temperature was reached more rapidly in the cases of high heat input rate for the sodium heat pipe.