• Resources Recycling
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• v.4 no.1
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• pp.31-37
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• 1995

This study was to investigate the effects oi agitation speed, pulp concentration, ion concentration ill the slurry solution, printed area of the waste newspaper, immerwng time and the temperature on the defiberation process for the waste newspaper. The defikration efficiency at 50% is twice that of 16%. The efficiency is improved as two times according to elevate the agtation speed as two times in the range of 200-2WO r.p.m.. Defiberation with NaOH 1X10-'M solution has higher efficiency than that of NaOH 1 x 1 0 - M solution as 3 times at the conditions of 16%, 1200 r.p.m, and 1% pulp concentration The temperature of immersing salut~on aifects on the efficiency more than immersing time does. Increasing the printed area of newspaper decreases the velocity of defiberation. The alkaline solution is effective to defiberate and the defiberation efficiency at the same dosage of alkalinity is in the order a1 NaOH) KOH) Na,SiO, ) Na,CO, ) Ca(OH)2.

• Resources Recycling
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• v.17 no.2
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• pp.36-45
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• 2008

Pickling of oxidized 304 stainless steel has been investigated using rotating disk electrode in waste acid solutions generated from the etching process of silicon wafer in order to recycle them. The waste acid solution contained acetic, nitric, hydrofluoric acids, and silicon of $19.6g/L^{-1}$. Electrochemical behavior during the pickling was distinctively different between the original and silicon-removed acid solutions. Open circuit potential was continuously changed in the original solution, while it was discontinuously changed and fluctuated in the silicon-removed solution. Fast and abrupt removal of surface oxide layer with severe pitting was observed in the silicon-removed solution. It was found that solution temperature had the most influential effect on glossiness. Surface glossiness after pickling was decreased with solution temperature. At the same condition, the glossiness was higher in the original solution than in the silicon-removed solution.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.32 no.4
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• pp.53-62
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• 2009

Lee[15] examined quantity discount contracts between a manufacturer and a retailer in a stochastic, two-period inventory model where quantity discounts are provided based on the previous order size. During the two periods, the retailer faces stochastic (truncated Poisson distributed) demands and he/she places orders to meet the demands. The manufacturer provides for the retailer a price discount for the second period order if its quantity exceeds the first period order quantity. In this paper we extend the above two-period model to a k-period one (where k < 2) and propose a stochastic nonlinear mixed binary integer program for it. In order to make the program tractable, the nonlinear term involving the sum of truncated Poisson cumulative probability function values over a certain range of demand is approximated by an i-interval piecewise linear function. With the value of i selected and fixed, the piecewise linear function is determined using an evolutionary algorithm where its fitness to the original nonlinear term is maximized. The resulting piecewise linear mixed binary integer program is then transformed to a mixed binary integer linear program. With the k-period model developed, we suggest a solution procedure of receding horizon control style to solve n-period (n < k) order decision problems. We implement Lee's two-period model and the proposed k-period model for the use in receding horizon control style to solve n-period order decision problems, and compare between the two models in terms of the pattern of order quantities and the total profits. Our computational study shows that the proposed model is superior to the two-period model with respect to the total profits, and that order quantities from the proposed model have higher fluctuations over periods.

• Journal of the Korea Safety Management & Science
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• v.15 no.4
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• pp.123-129
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• 2013

Among various manual materials handling tasks, pushing/pulling was known to be one of the risk factors for the low back and shoulder musculoskeletal disorders (MSDs). This study was conducted to find out an optimal solution set of the handle height and distance for 4-wheel cart with two vertical handles. Ten male college students participated in the pushing force measurement experiment. The face-centered cube design, one of the central composite designs, was applied for the experiment, and the isometric voluntary pushing force was measured in 9 treatment conditions. The second order response surface model was predicted by using the pushing strength as a response variable, and the handle height and distance as independent factors. According to the 2nd order response model, the handle height and distance showed nonlinear relationship with the isometric pushing strength. To maximize the 2nd order response model (pushing force), the handle height and distance were optimized. The optimal handle height was 'xyphoid process height - stature', and the optimal handle distance was '$1.25{\times}shoulder$ width'. When calculated using the anthropometric data of the subjects of this study, the optimal handle height was $115.4{\pm}3.4$ cm, slightly higher than the elbow height, and the handle distance was $52.9{\pm}2.3$ cm.

• Journal of Korean Society of Steel Construction
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• v.11 no.1 s.38
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• pp.55-67
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• 1999

The ratios of elastic to shear modulus of the structures as laminated composite plates and shells, are very large. They are much susceptible to effect of shear deformation. In order to obtain the accurate solutions of laminated composite plate and shells, the effects of shear strain should be considered for the analysis and design of them. Especially, the more exact solution can be obtained in applying to higher-order shear deformation theory. Therefore, in this paper, the third-order shear deformation theory is used to present the distributions of bending, the characteristics of natural frequencies and the buckling load according to the effects of ply orientation, number of layers for the laminated composite plates and shells with simply supported boundary conditions.

• Environmental Engineering Research
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• v.21 no.2
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• pp.203-210
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• 2016

Hybrid materials were obtained modifying the bentonite (BC) and local clay (LC) using hexadecyltrimethylammonium bromide (HDTMA) or the clay were pillared with aluminum followed by modification with HDTMA. The materials were characterized by the SEM, FT-IR and XRD analytical tools. The batch reactor data implied that the uptake of $17{\beta}$-estradiol (E2) by the hybrid materials showed very high uptake at the neutral pH region. However, at higher and lower pH conditions, slightly less uptake of E2 was occurred. The uptake of E2 was insignificantly affected changing the sorptive concentration from 1.0 to 10.0 mg/L and the background electrolyte (NaCl) concentrations from 0.0001 to 0.1 mol/L. Moreover, the sorption of E2 by these hybrid materials was fairly efficient since within 30 mins of contact time, an apparent equilibrium between solid and solution was achieved, and the data was best fitted to the PSO (pseudo-second order) and FL-PSO (Fractal-like-pseudo second order) kinetic models compared to the PFO (pseudo-first order) model. The fixed-bed column results showed that relatively high breakthrough volume was obtained for the attenuation of E2 using these hybrid materials, and the loading capacity of E2 was estimated to be 75.984, 63.757, 58.965 and 49.746 mg/g for the solids BCH, BCAH, LCH and LCAH, respectively.

• Structural Engineering and Mechanics
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• v.21 no.2
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• pp.151-168
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• 2005

In this paper an energy method is presented for the linear buckling analysis of first order shear deformable plates. The displacement fields are defined in terms of the shape functions, which correspond to a set of predefined points and are composed of significantly high order polynomials. The locations of these points are found by mapping the geometry using the naturalized coordinates and bilinear shape functions. In order to evaluate the method, fully clamped and simply supported rectangular plates subjected to uniform uniaxial compressive loading on two opposite edges of the plate are investigated thoroughly and the results are compared with the exact solution given in the monograph of Timoshenko and Gere (1961). The method is extended to the analysis of perforated plates, wherein the negative stiffness computed over the opening area from in-plane and out-of-plane deformation modes is superimposed to the stiffness of the full plate. Numerical results are then favorably compared with those obtained by finite element methods. Other cases such as; rectangular plates with eccentrically located openings of different shapes are studied and reported in this paper with regards to the effect of aspect ratio, hole size, and hole position on the buckling. For a square plate with a large circular opening at the center, diameter being 80 percent of the length, the present method yields buckling coefficient 12.5 percent higher than the one from the FEM.

• Journal of Korean Society of Steel Construction
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• v.9 no.3 s.32
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• pp.333-340
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• 1997

This paper will expand the third-order shear deformation theory by the double-Fourier series and reduce to the solution of a system of ordinary differential equations in time, which are integrated numerically using Newmark's direct integration method and clarify the undamped dynamic responses for the cross-ply and antisymmetric angle-ply laminated composite plates and shells with simply supported boundary condition. Numerical results for deflections are presented showing the effect of side-to-thickness ratio, aspect ratio, material anisotropy, and lamination scheme.

• Journal of Embryo Transfer
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• v.26 no.3
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• pp.159-164
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• 2011

This study was performed in order to determine optimum flushing solution using the direct embryo collection (DEC). Donors, at random stages of the estrous cycle, received a CIDR. 7 days later, 200 mg FSH was treated with 40, 30, 20, 10 mg FSH levels in declining doses twice daily by intramuscular injection for 4 days. On the 3$^{rd}$ day administration of FSH, 25 mg $PGF_2{\alpha}$ was administered and CIDR was withdrawn. After FSH injections were complete, donors were artificially inseminated twice at 12 hr intervals. The donor cattle received 250 ${\mu}g$ GnRH at time of 1$^{st}$ insemination and embryos were recovered 8 days after the 1$^{st}$ insemination. Embryo collection from superovulated donors were performed to flushing by DEC and conventional method. As a results, the average number of recovered embryos were significantly higher as 19.1${\pm}$1.40 with DEC method than 12.0${\pm}$0.44 with conventional embryo collection method, respectively (p<0.05). Also, The average number of transferable embryos were significantly higher (p<0.05) as 15.8${\pm}$1.72 with DEC method than 6.9${\pm}$0.35 from conventional embryo recovery procedures. Meanwhile, number of recovered embryos and number of recovered transferable embryos following the number of flushing times until 6${dr}$ flushing were significantly higher as 8.6${\pm}$0.53 and 8.6${\pm}$0.53 from 2$^{nd}$ flushing time than other groups (p<0.05). No. of Ear. B stage embryos were significantly higher as 3.9${\pm}$0.90 and 3.9${\pm}$0.90 with 2$^{nd}$ flushing time in total collected embryos and transferable embryos (p<0.05). Com M stage embryos were significantly higher as 3.7${\pm}$1.00 in 2$^{nd}$ flushing time and as 2.2${\pm}$0.76 in 3$^{rd}$ flushing time for recovered embryos (p<0.05). In transferable embryos, Com. M stage embryos were significantly higher (p<0.05) as 3.7${\pm}$1.00 in 2$^{nd}$ flushing time and as 2.2${\pm}$0.76 in 34$^{dr}$ flushing time, also. No. of degradation embryos was significantly higher as 2.2${\pm}$0.72 in 5${rd}$ flushing time, On the other hand, degradation embryos was not observed in transferable embryos (p<0.05). In conclusion, these results suggest that DEC method should effective methods for production of in vivo embryos using less flushing solution following perform until 4$^{rd}$ flushing time than conventional embryo collecting method. Also, it might be effectively collection of transferable embryos following more less procedure times compared to conventional embryo recovery methods.

• Journal of Society of Preventive Korean Medicine
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• v.10 no.1
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• pp.141-153
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• 2006

In order to study the changes in hematology and serum chemistry of rats injected with glycerol, Sprague-Dawley albino rats weighing 240 to 260 gm were injected intramuscularly with a 50% solution of glycerol(8ml/kg). We measured the values of hematology and serum chemistry, and compared the measured values of S1 group(passed for 1day after injection of glycerol), S2 group(passed for 2days after injection of glycerol), S3 group(passed for 3days after injection of glycerol), S4 group(passed for 3days after injection of glycerol) and S5 group(passed for 4days after injection of glycerol) with those of Normal group(non-treated group). The results are summarized as follows : 1. In body temperature, S1, S2, S4 groups showed significantly higher compared with Normal group, especially S2 group was higher than S1 group(p<0.05). But S5 group was lower than Normal group(p<0.05). 2. In RBC, S1 group was lower than Normal group(p<0.05). And in Hct, S1, S2, S3 groups were lower than Normal group(p<0.05), in Hb, S1 and S3 groups were lower than Normal group(p<0.05). 3. In WBC, S1, S2 groups were higher than Normal group(p<0.05). and in WBC differential count, S2, S3, S5 groups were higher than N, S1, S4 groups in monocyte(p<0.05). 4. In GOT, S1 group was higher than Normal group(p<0.05), and S2, S3, S4, S5 groups were lower than S1 group(p<0.05). In GPT, S1 group was higher than Normal group(p<0.05), and S2, S3 groups were lower than S1 group(p<0.05), S4, S5 groups were lower than N, S1, S2, S3 groups(p<0.05). 5. In total cholesterol and creatinine, S4 group was higher than Normal group(p<0.05). According to the above experimental results, we could find the anemia, inflamation, damage of renal function for 4 days by intramuscularly injection with a 50% solution of glycerol(8ml/kg) in rat.