• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.46 no.6
• /
• pp.34-40
• /
• 2014

Wood fibers for medium density fiberboard (MDF) was used in the filler layer of the white duplex board for increasing thickness and bulk of the board. The MDF fibers and the old corrugated container (OCC) furnish were refined, and mixed together to form paperboard. At optimum mixing ratios and refining degrees, stiffness and tensile strength of the MDF fiber-containing board were higher than those of the board with 100% OCC. It was found that there was possibility to reduced basis weight of the filler layer down to 90% of the all OCC furnish by judicious selection of the mixing ratio and the refining method of the MDF fibers. Drainage rate increase and potential drying energy savings were additional benefits.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.22 no.1
• /
• pp.96-100
• /
• 1993

The changes in the concentration of toropherol and carotenoid in pinenut oil at various stage of refining are studied during autoxidation. The oxidative stability of pinenut oil decreased with the refining degree increased. The tocopheol content of total crude oil was 55.51mg/100g oil and $\alpha$, ${\gamma}$and $\beta$-tocopherol in the crude oil were 25.48mg, 23.94mg and 6.99mg in order, respectively. The amount of $\delta$-tocopherol was trace. The concentrations of $\alpha$, ${\gamma}$ and $\beta$-tocopherol in pinenut oil after degumming or alkaline refining were 23. 85mg, 19.79mg and 6.12mg or 24.08mg, 24.04mg and 5.33mg, respectively. The content of f-carotene was 0.63% of total unsaponifiable materials and that of lycopene was trace. The concentrations of carotenoids and toropherols in pinenut oil decreased while autoxidation progressed. Degrees of destruction of carotenoids and toropherols. were significant at first stage of oxidation. Decrease in $\alpha$-toropherol was found to be faster than that in $\alpha$, ${\gamma}$-tocopherol during oxidation.

• Carbon letters
• /
• v.11 no.3
• /
• pp.192-200
• /
• 2010

Common reed (Fragmites australis), a local invasive grass, was investigated as a possible feedstock for the production of activated carbon. Dried crushed stems were subjected to impregnation with phosphoric acid (30, 40 and 50%) followed by pyrolysis at $400{\sim}500^{\circ}C$ with final washing and drying. Obtained carbons were characterized by determining: carbon yield, ash content, slurry pH, textural properties and capacity to remove color bodies from factory-grade sugar liquor. Produced carbons possessed surface area up to 700 $m^2/g$, total pore volumes up to 0.37 $cm^3/g$, and proved to be microporous in nature. Decolorization of hot sugar liquor at $80^{\circ}C$ showed degrees of color removal of 60 up to 77% from initial color of 1100~1300 ICU, at a carbon dose of 1.0 g/100 ml liquor. No correlation seems to hold between synthesis conditions and % R but depends on the degree of microporosity. A commercial activated carbon N showed a comparative better color removal capacity of 91%. Common reed proved to be a viable carbon precursor for production of good adsorbing carbon suitable for decolorization in the sugar industry, as well as in other environmental remediation processes.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.12 no.4
• /
• pp.892-899
• /
• 1988

A container crane model was tested to investigate wind-load characteristics in uniform flows and ground boundary layers. Drag coefficients and moment coefficients show their minimum values at 0, 90, 180 degrees wind directions and maximum values at 60 and 120 degrees. Strong interactions among structure elements produce such variations of the wind-load with wind directions. The BS-2573 code is shown to over-estimation can be reflected in the design stage of cranes by refining the rule of the designer. Some roundings of coners of the engine room and the machinery room reduce the wind-load by 10 percents. Considerable reductions of the wind-load would be expected if further integrated development of the crane structure are executed.

• Journal of the Korean Wood Science and Technology
• /
• v.39 no.4
• /
• pp.281-290
• /
• 2011

We analyzed the basic characteristics and adsorption property of carbonized materials from thinning byproducts of major Korean wood species for evaluating as charcoal making raw material. Yield of charcoal was decreased with increasing the carbonization temperature for all wood species. Refining degrees was 9.0 at $400^{\circ}C$, 3.3~5.0 at $600^{\circ}C$ and 0 at $800^{\circ}C$, and was no difference among wood species. With increasing the carbonization temperature, the fixed carbon content was also increased, and charcoal from softwoods had more fixed carbon content than that from hardwoods. Specific surface area was increased with increasing the carbonization temperature, softwood charcoal had more specific surface area than that of hardwood. Pinus rigida showed the highest specific surface area. In formaldehyde removal by charcoal, some materials had highest at $600^{\circ}C$ and the others had highest at $800^{\circ}C$. Pinus koraiensis, Qurcus acutissima and MDF showed maximum formaldehyde removal ability at $600^{\circ}C$. Ethylene gas removal ability of charcoal was increased with increasing the carbonization temperature, and the charcoal from Pinus rigida and Robinia pseudoacacia had higher ethylene gas removal ability than the other species.

• Korean Journal of Materials Research
• /
• v.9 no.3
• /
• pp.322-326
• /
• 1999

In this study, cold-rolling and appropriate annealing was adopted for the grain refining of Cu-26.65Zn-4. 05Al-0.31Ti(wt%) shape memory alloy. For the cold deformation of this alloy the ducti1e $\alpha$-phase must be contained. After heat treatment at $550^{\circ}C$ the $(\alpha+$\beta)$-dual phase with 40vol.% $\alpha$-phase was obtained which could be rolled at room temperature. This alloy was cold rolled into a final thickness of 1.0mm with total reduction degrees of 70% and 90%. The rolled sheets were betanized at $800^{\circ}C$ for various times, then quenched into ice water. The grain size of co]d rolled samples were $60~80\mu\textrm{m}$ which is much smaller comparing with the hot-rolled samples. And the 90% rolled sample showed smaller grain size than the case of the 70% rolled one. The small grain size had influence on the phase transformation temperatures and stabilization of the austenitic phases.

• Journal of the Korean Society for Heat Treatment
• /
• v.3 no.4
• /
• pp.1-9
• /
• 1990

In this study, the ausformed martensite cooled to $-196^{\circ}C$ with various deformation degrees in Fe-30%Ni-0.24%C alloy was transformed to reversed austenite at $500^{\circ}C$ by cyclic reverse martensitic transformation. The effects of prior deformation and the number of cyclic reverse transformation on the microstructure and the mechanical properities of reversed anstensite were investigated. Experimental results showed that the strength of reversed austenite was higher than that of original austenite. This is due to higher dislocation density and grain refining. The reversed austenite formed from ausformed martensite was highly strengthened by prior deformation. This strengthening effect of reversed austenite is attributed to higher dislocation density than grain fefining. The yield strength of reversed austenite below 30% prior deformation, but above 30% prior deformation the strength of reversed austenite is lower than that of deformed austenite. This is due to partly disappearance of strain hardening effect at higher deformation degree by reverse transformation. The strength of reversed austenite is increased with the number of cyclic transformation. Especially, it is principally strengthened by the first cyclic transformation and shows higher increase in yield strength than that of ultimate tensile strength.

• Journal of the Korean Magnetic Resonance Society
• /
• v.17 no.1
• /
• pp.11-18
• /
• 2013

Rapid advances of computational power and method have made it practical to apply the time-consuming calculations with all-atom force fields and sophisticated potential energies into refining NMR structure. Added to the all-atom force field, generalized-Born implicit solvent model (GBIS) contributes substantially to improving the qualities of the resulting NMR structures. GBIS approximates the effects that explicit solvents bring about even with fairly reduced computational times. Although GBIS is employed in the final stage of NMR structure calculation with experimental restraints, the effects by GBIS on structures have been reported notable. However, the detailed effect is little studied in a quantitative way. In this study, we report GBIS refinements of ubiquitin and GB1 structures by six GBIS models of AMBER package with experimental distance and backbone torsion angle restraints. Of GBIS models tested, the calculations with igb=7 option generated the closest structures to those determined by X-ray both in ubiquitin and GB1 from the viewpoints of root-mean-square deviations. Those with igb=5 yielded the second best results. Our data suggest that the degrees of improvements vary under different GBIS models and the proper selection of GBIS model can lead to better results.

• Journal of Labour Economics
• /
• v.29 no.2
• /
• pp.117-143
• /
• 2006

This paper illuminates the patterns of growth and declines in sizes of union membership in metal, chemical, financial, and auto transport sectors in three distinct periods during the last four decades from 1963 to 2003. This paper also calculates union densities in auto assembly, auto supply, and shipbuilding industries of the metal sector, cement, petroleum refining, and pharmaceutical industries of the chemical sector, private banking industry of the financial sector, and city bus industry of the auto transport sector. Such diversities in both sizes of union membership and union densities among sectors and industries turned out to be associated with attitudes and choices of employers and unions in interaction with sector- and industry-specific economic (growth stage and path), institutional (degrees of government intervention), and social (demographic features of employees and prevailing sizes of firms) environment. Such finding shows that theoretical reasonings on sizes of union membership and union densities across sectors and industries in advanced nations are also relevantly useful to analyze the Korean case.

• Environmental and Resource Economics Review
• /
• v.20 no.4
• /
• pp.663-688
• /
• 2011

Since the liberalization of petroleum product prices in 1997, there has been persistent suspicion with regard to asymmetry in the movement of petroleum product prices in Korea. In particular, academics and consumer groups suggest that prices decided by refining companies and gas stations have moved asymmetrically compared with international petroleum product prices. The primary aim of this study is to determine, using the Error Correction Model, to perform multi-country asymmetry analysis including the United States, the United Kingdom, Germany, France, Italy and Japan. We shows that comparison of domestic prices with international prices in the six countries mentioned above revealed a fairly low level of asymmetry in those countries, although some asymmetry was found in some countries at various times within the period of analysis. To explain the different degrees of asymmetry between countries, this study looked at asymmetry in the United States, Germany and Italy and sought correlations between each country's oil industry structure and its level of competition.