• Journal of the Korean Arthroscopy Society
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• v.4 no.1
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• pp.13-18
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• 2000

Purpose : The purpose of this study was to compare the efficacy of bone-patellar tendon-bone(B-PTB) allograft with autograft B-PTB reconstruction of anterior cruciate ligament(ACL) according to the subjective and objective criteria. Materials and Methods : 42 patients were treated for acute rupture or chronic insufficiency of the ACL between March 1993 and June 1996. There were 18 autografts and 24 allografts for ACL reconstruction. At 2 years of follow-up after operation, autograft and allograft groups were compared based on subjective, objective criteria and Telos stress arthrometer. Results : The modified Feagin Scoring System revealed 16 patients$(88.9\%)$ with a satisfactory result by autografts, but 21 patients$(87.5\%)$ with a satisfactory result by allografts after 2-years follow-lip. There was no statistically significant difference between the two groups. ACL reconstruction with B-PTB allograft did not produce a significant functional deficit. But patellofemoral pain and crepitus were more frequent in the autografts$(33.3\%)$ than allografts$(8.3\%)$ (p<0.05). Conclusion : The ACL deficient knees treated with allografts for ACL reconstruction tended to be better than those reconstructed with autografts fur the reduction of patellofemoral crepitus and pain. B-PTB allograft provides an acceptable alternative to autograft tissue for reconstruction of the ACL.

• Clean Technology
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• v.23 no.1
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• pp.73-79
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• 2017

Recently usage of biomass is increased in pulverized coal power plants for reduction of $CO_2$ emission. Many problems arise when thermal share of the biomass is increased, and milling of the biomasses is one of the most important problems due to their low grindability when existing coal pulverizer is used. Grindability of coal can be measured through the HGI (Hardgrove grindability index) equipment as a standard, but method of measuring biomass grindability has not been established yet. In this study, grinding experiment of coal and biomass was performed using a lab-scale ball mill. One type of coal (Adaro coal) and six biomasses (wood pellet (WP), empty fruit bunch (EFB), palm kernel shell (PKS), walnut shell (WS), torrefied wood chip (TBC) and torrefied wood pellet (TWP)) were used in the experiment. Particle size distributions of the fuels were measured after being milled in various pulverization times. Pulverization characteristics were evaluated by portion of particles under the diameter of $75{\mu}m$. As a result, about 70% of the TBC and TWP were observed to be pulverized to sizes of under $75{\mu}m$, which implies that they can be used as alternative biomass fuels without modification of the existing mill. Other biomass was observed to have low grindability compared with torrefied biomass. Power consumption of the mill for various fuels was measured as well, and the results show that lower power was consumed for torrefied biomasses. This result can be used for characterization of biomass as an alternative fuel for pulverized coal power plants.

• The Korean Journal of Air & Space Law and Policy
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• v.35 no.1
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• pp.127-152
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• 2020

Despite growing international cooperation for maintenance of international peace and security, wars continue to occur due to conflicted state interests. Continuing conflicts has advanced development of various weapon systems such as global integrated intelligence, surveillance and reconnaissance. However, with a big increase in the number of civilian casualties caused by the weapon systems development, the international community has also advanced diplomatic efforts to minimize deaths of civilian and military personnel. Therefore, it is essential to observe the principle of discrimination between combatants and non-combatants when operating unmanned aerial vehicles (UAVs), better known as drones. Drones have become more capable of distinguishing combatants from non-combatants due to its high-tech prowess. In the operation of drones, any parties involved in combat or the war are responsible for mounting civilian casualties. In addition, it should comply with the principle of proportionality that calls for a balance between results of such action and expected military advantage anticipated from the attack. The rule of proportionality prohibits use of military force which may be expected to cause excessive civilian harm. Drones have been able to track and monitor targets for hours and select the accurate locations of the targets. The aim is to reduce civilian losses and damage to a minimum. Drones meet the standards of Article 51.4 of the Additional Protocol.

• Journal of Conservation Science
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• v.29 no.4
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• pp.345-354
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• 2013

This study analyses geochemistrical, microscopic, mineralogical characteristics of coals which have been collected from in and out of the shipwreck No 1 of Mado island during underwater excavation in Taean. The result from mineralogical and geochemical analysis reveals that the specific gravity of the coals is $1.28g/cm^3$. Considering that coals contains 10% mineral of it and the specific gravity of the pure is $1.15g/cm^3$, it is believed that the collected coals would be lignite or biturminous coal. The X-ray diffraction analysis which displays the peak of $2{\theta}$ is 20~25C degree, proves that the collected coals would be categorised as low rank coal. The collected coals is composed of: 93%-94%(93.5%) of vitrinite maceral group, 5%-6%(5.5%) of exinite maceral group, and 1% of inertinite maceral group. In addition, the average of reflection rate is $R_{mean}$: 0.627 showing that it would be either high volatile bituminous C coal or sub-bituminous C coal. Such result confirms that the coal is sub-bituminous C or high volatile bituminous C coal in accordance with the U.S Bureau of Mine(USBM) classification system. The element analysis reveals that the coal is the coking coal which is grouped as the bituminous coal. Comparative analysis between the coals of Mado Shipwreck No 1 and domestic coals shows that the coals of Mado Shipwreck is similar to the bituminous coal used in the area of Janggi in Pohang city.

• Clean Technology
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• v.17 no.4
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• pp.336-345
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• 2011

The total area of forest land in Korea is 64.2%, and significant forest resources can continuously be produced. However our country didn't separate the recyclable waste wood and was illegal landfill or incinerated. In this study, waste-wood and rice husk of biomass and low-grade-anthracite made refuse derived fuel by mixing and compressing. In addition, the binding effect of binders and additives were analyzed. Physical and chemical characteristics of manufactured refuse derived fuel were analyzed and evaluated suitability by compared with quality standards. A result of change with compressed and relaxed density, added 20% anthracite and 10% rice husk is optimal density change and average density increased large range when 20 wt.% P.V.A., guargum, molasses and 10 wt.% starch were added. All fuel samples be distributed over 3,500 kcal/kg LHV and grade of No. 3~4 fuels appeared. A result of the characteristics of physical and chemical compressed biomass refuse derived fuel with addictive, 12.9% of durability improvement appeared when is mixing asphalt and 5.8% of durability improvement appeared when is mixing rice bran by pretreatment of NaOH 5%.

• Korean Chemical Engineering Research
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• v.56 no.5
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• pp.631-640
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• 2018

The application of an oxy-combustion circulating fluidized bed combustor (Oxy-CFBC) for low grade coals has recently developed in the world to meet the continuous increase of energy demand and to achieve the reduction of greenhouse gases. Since demo plants for Oxy-CFBC have been developed, the combustion properties of Oxy-CFBC in various operation conditions, such as gas flow rates, combustion temperature, fuel, and so on, should be investigated to develop design criteria for a commercial Oxy-CFBC. In this study, a computational simulation tool for Oxy-CFBC was developed on the basis of the IEA-CFBC (International Energy Agency Circulating Fluidized Bed Combustor) model. Simulation was performed under various conditions such as reaction temperature ($800^{\circ}C{\sim}900^{\circ}C$), oxygen contents (21%~41%), coal feeding rate, Ca/S mole ratio (1.5~4.0), and so on. Simulation results show that the combustion furnace temperature is higher in oxy 1 than air fired. However, the temperature gradient tended to decrease with increasing oxy mixing percent. In case of $SO_x$, the higher the Ca/S mole ratio and oxy mixing percent, the higher the desulfurization efficiency.

• Korean Journal of Food Science and Technology
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• v.35 no.4
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• pp.586-590
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• 2003

Removal rates of residual organic phosphorous pesticides (chlorpyrifos-methyl and fenitrothion) in Perilla leaves by various washing methods were determined. The removal rates using stagnant tap water were 20.05 and 17.70% for chlorpyrifos-methyl and fenitrothion, whereas 44.28 and 39.10% using flowing tap water, and 19.14 and 15.43% using activated carbon-added stagnant tap water, respectively. Activated carbon-added flowing stagnant tap water removed 25.29 and 15.43% of chlorpyrifos-methyl and fenitrothion, and removal rates were 53.51 and 50.62% with alkaline solution and 30.25 and 28.09% with acidic solution, respectively. With neutral detergent solution, removal rates were 81.52 and 76.56% for chlorpyrifos-methyl and fenitrothion, respectively. Results revealed washing method using neutral detergent solution was most effective for removing residual pesticides.

• KSBB Journal
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• v.23 no.6
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• pp.494-498
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• 2008

We investigated the bioethanol production using wood biomass hydrolysate which obtained from the supercritical water (SCW) treatment. SCW-treated hydrolysate was used C-source of culture medium in shaking flask culture for bioethanol production. When the concentrated SCW-treated hydrolysate (SCW3) was used, yeast cell growth was slower compared with those in other SCW-treated hydrolysate (SCW1, SCW2). In addition, the bioethanol productions were 0.51 to 0.56 (%,w/v) when SCW1, SCW2, and SCW3 were used. Therefore, we removed the toxic phenolic compound in SCW-treated hydrolysate by pretreatments of activated charcoal and calcium hydroxide. Activated charcoal reduced more efficiently the phenolic compounds in SCW3 by 94.6%. Finally, when we pretreated SCW3 by activated charcoal and this was used for bioethanol production, 0.96 (%,w/v) bioethanol was produced and the ethanol yield based on reducing sugar reached 0.5.

• Journal of the Korea Institute of Building Construction
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• v.16 no.1
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• pp.77-85
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• 2016

This study provides the numerical model to assess retrofit and strengthen levels in the dispersal and combat facilities. First of all, it is verified that direct-hitting projectiles are more destructive to the structures rather than close-falling bombs with explosion tests. The protective capacity of dispersal and combat facilities, which are modeled with soil uncertainty and structural field data, is analyzed through finite element method. With structural survivability and facility data, the logistic regression model is drawn. This model could be used to determine the level of the retrofit and strengthen in the dispersal and combat facilities of contact areas. For more reliable model, it could be better to identify more significant factors and adapt non-linear model. In addition, for adapting this model on the spot, appropriate strengthen levels should be determined by hands on staffs associated with military facilities.

• Economic and Environmental Geology
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• v.54 no.4
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• pp.483-494
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• 2021

This study was carried out to investigate the feasibility of reducing clean cover soil using a flooded column test in arsenic-contaminated farmland reclamation of abandoned coal mine area that shows generally low or about worrisome level (25 mg/kg) of Korea soil environment conservation act unlike abandoned metal mine. During the monitoring period of soil solution for 4 months, chemical properties (pH, EC, ORP, Fe, Mn, Ca, and As) in each layer (clean soil cover and contaminated/stabilized soil) showed different variation. This result revealed that soil solution in stabilized or contaminated soil rarely affected that in cover soil. Whether stabilized or not, arsenic concentrations in the rice roots grown in the soil covers with the thickness of 40 cm decreased by 98% in compared with the that grown in the control soil. In case of the soil covers with 20 cm thickness on stabilized soil, it decreased by 80% and this was 22 percentage point higher than when the soil of lower layer was not stabilized. Thus, reducing clean cover soil could be possible in contaminated farmland soil reclamation if appropriate stabilization of contaminated soil is carried.