• Resources Recycling
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• v.32 no.2
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• pp.12-18
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• 2023

In 2018, the demand for silver (referred to as Ag) in the electrical and electronics sector was 249 million tons. The demand stood at 81 million tons in the solar module production sector. Currently, due to the rapid increase in solar module installation, the demand for silver is increasing drastically in Korea. However, Korea's natural metal resources and reserves are insufficient in comparison to their consumption, and the domestic silver ore self-sufficiency rate was as low as 2.2% as of 2021. This implies that a recycling technology is necessary to recover valuable metal resources contained in the waste plating solution generated in the metal industry. Therefore, this study compared and analyzed, the results of the impact evaluation through life cycle assessment according to an improvement in the process of recovery of valuable metals in the waste plating solution. The process improvement resulted in reducing GWP (Global Warming Potential) and ADP(Abiotic Depletion Potential) by 50% and 67%, respectively. The GWP of electricity and industrial water was reduced by 98% and 93%, respectively, which significantly contributed to the minimization of energy and water consumption. Thus, the improvement in recycling technology has a high potential to reduce chemical and energy use and improve resource productivity in the urban mining industry.

• Elastomers and Composites
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• v.34 no.2
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• pp.135-146
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• 1999

The thermal degradation kinetics of SBR and tire were studied using a conventional thermogravimetric analysis in the stream nitrogen at a heating rate of 5, 10, 15, $20^{\circ}C/min$, respectively. Thermogravimetric curves and their derivatives were analyzed using various analytical methods to determine the kinetic parameters. The degradation of the SBR and tire was found to be a complex process which has multi-stages. The Friedman method gave average activation energies for the SBR and tire of 247.53kJ/mol and 230.00kJ/mol, respectively. Mean-while, the Ozawa method Eave 254.80kJ/mol and 215.76kJ/mol. It would appear that either. Friedman's differential method or Ozawa's integral method provided satisfactory mathematical approaches to determine the kinetic parameters for the degradation of the SBR and tire. Approximately 86% and 55% of oil products were obtained at a final temperature of $700^{\circ}C$ and a heating rate of $20^{\circ}C/min$ for the SBR and tire respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.7
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• pp.3327-3333
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• 2011

The interest on the recovery of thermal energy using the industrial waste has been rising to solve the problems of continuous increase of waste generation and the depletion of the fossil fuel recently. To recovery from the waste among the new recyclable energies has been proved as the most favorable when the potential value of energy source is compared. The RDF made from the industrial waste has been approved as the most economical method. This research has analyzed the heavy metal components containing in the industrial waste. The concentration of Cl and S in the industrial waste generated in C-industrial complex are slightly high than that of the B- and A-industrial complex. The main components generated from A-industrial complex, B-industrial complex, and C-industrial complex are alumina-silicates, calcium alumina silicates, and the mixture of lime and calcium alumina silicate. These results could be used to reveal the origin of inorganic components in industrial waste and utilized as a basic data to improve the performance of the RDF as fuel.

• Journal of the Korean Chemical Society
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• v.44 no.6
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• pp.581-586
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• 2000

Separation and coulometric titration method were applied for the determination of plutonium content in samples of PWR spent fuel. Plutonium was separated on an anion exchange(AG MP-1) column and determined by the controlled-potential coulometric titration. In this study, we discussed some experimental conditions related to the separation and determination of plutonium in PWR spent fuel samples. Average accuracy(recovery of plutonium) for the determination of 0.230∼3.02 mg plutonium standard was 99.36%. Average precision(relative standard deviation, RSD) for the determination of 0.250∼0.450 mg plutonium in PWR spent fuel samples was 0.38%.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.204-204
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• 1999

The plasma source ion implantation(PSII) technique which is a method using high negative voltage pulse in plasma system has the potential to change the surface properties of polymer. PSII technique increase the surface free energy by introducing polar functional groups on the surface so that it improves reactivity, hydrophilicity, adhension, biocompatability, etc. However, the mobility of polymer chains enables the modified surface layers to adapt their composition to interfacial force. This hydrophobic recovery interrupts the stability of modified surfaces to keep for the long time. In this study, poly(methyl methacrylate)(PMMA), poly(2-hydroxyethyl methacrylate)(PHEMA), and polu(2-hydroxypropyl methacylate)(PHPMA) for contact lens application, were modified to improve the wettability with PSII technique and were investigated the surface stabilities. Polymer film was prepared with solution casting(3 wt.% solution) and was annealed at 11$0^{\circ}C$ under vacuum oven to remove solvent completely and to eliminate physical ageing. The thickness of the film measured by scanning electron microscopy (SEM) and surface profilometer was about 10${\mu}{\textrm}{m}$. Polymers were treated with different kinds of gases, pulse frequency, pulse with, pulse voltage, and treatment time. Even though PMMA, PHEMA, and PHPMA have similar repeat unit structure, the optimal treatment conditions and the tendency to hydrophobic recovery were different. PHPMA, more hydrophilic polymer than PMMA and PHEMA showd better wettability and stability after mild treatment. Surface tensions were obtained by water and diiodomethane contact angle measurements to monitor the relation between hydrophobic recovery and polymer structure. Different ion species in plasma change the polar component and dispersion component of polymer surface. For better wettability surface, the increase of polar component was a dominant factor. We also characterized modified polymer surfaces using x-ray photoelectron spectroscopy(XPS), secondary ion mass spectrometry(SIMS), Fourier Transform infrared spectroscopy(FT-IR), and SEM.

• Korean System Dynamics Review
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• v.5 no.2
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• pp.89-123
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• 2004

Using materials recovered from the waste stream instead of virgin resources as a raw material in manufacturing has great environmental and economic benefits. However, there is lack of public interest in needs for integrated waste management and its relevant facilities, because of NIMBY syndrome, This article has proposed a system dynamics model for the study of the potential and systemic consequences of resource circulation management system(RCMS) policy for a Sudokwon landfill site in Korea. The results of the study indicate that the effects of RCMS are seen continuously to increase in term with both the community welfare level and the resource and energy level. Moreover the effects of RCMS appear sharply in the first half of the simulation period.

• Journal of Chest Surgery
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• v.22 no.4
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• pp.580-588
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• 1989

The potential for enhancing myocardial protection by adding high-energy phosphate to cardioplegic solutions [St. Thomas Hospital solution] was investigated in a rat heart model of cardiopulmonary bypass and ischemic arrest. Creatine phosphate was evaluated as an additive to the St. Thomas Hospital cardioplegic solution. Creatine phosphate 10.0 mmol/L as the optimal concentration which improved recovery of aortic flow and cardiac output after a 30 minute period of normothermic [37oC] ischemic arrest. In comparing mechanical function in both groups the mean postischemic recoveries of aortic flow, cardiac output, stroke volume and stroke work [expressed as a percentage of its preischemic control] were significantly greater in STH-CP group than in CP- free control group. In addition to improving function and decreasing CK release, CP reduced reperfusion arrhythmias significantly decreasing the time between cross-clamp removal and return to regular rhythm from 81.8 * 13.9 [sec] in CP-free group to 35.9 * 6.8 [sec] in CP group [P< 0.05] so, exogenous CP exerts potent protective and antiarrhythmic effects when added to the St. Thomas Hospital cardioplegic solution. However, the mechanism of action remains to be elucidated.

• Journal of Soil and Groundwater Environment
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• v.21 no.2
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• pp.22-28
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• 2016

In order to evaluate landfill stabilization based on organic carbon, stoichiometric analysis and a biological methane potential (BMP) test based on modeling were performed at the 2^nd Sudokwon Landfill Site. Mass balance analysis through a BMP test proved to be more adaptable for evaluation, and it showed that 28.9% of landfill organic carbon was expected to remain by 2046, 30 years after landfill closure. The organic carbon ratio of total landfill waste for 2046 is forecasted as 2.9% in demolition waste and 5.1% in household waste, and, if one were to consider plastic as an organic waste, the ratios would increase to 15.9% and 28.3%, respectively. Therefore, it seems that organic matter biodegradation facilitating measures such as bioreactor landfill technology and preemptive recovery of combustible waste are necessary to shorten post closure management periods and to meet the landfill stabilization guidelines more safely.

• Proceedings of the KIPE Conference
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• 2010.11a
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• pp.62-63
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• 2010

This paper presents a potential for application of Inductive Power Transfer(IPT) to the light railway vehicle system. IPT system allows for a vehicle fitted with existing or new generation batteries to park over a small charging unit and commence charging immediately. Regular charging will allow for smaller batteries to be used in vehicles. In this paper, IPT system uses a full-bridge LLC resonant converter and is possible for the regenerative braking which is an energy recovery mechanism.

• The Journal of Korean Medicine
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• v.42 no.1
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• pp.129-135
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• 2021

Objectives: The present study reports case of an elderly kwashiorkor patient who was treated with Korean Medicine. Methods: A 68-year-old female patient with weight loss, general weakness, chills, anorexia, and dizziness after over 100 episodes of diarrhea visited the hospital. Blood tests showed hypoalbuminemia and anemia, and ultrasonography revealed fatty liver disease. The patient was diagnosed with kwashiorkor, and her symptom differentiation was Yang deficiency followed by Both Qi-Blood deficiency. Sayeok-Tang, Soshiho-Tang, Insamyangyeong-Tang, and Gongjin-Dan, herbal drugs, were given to the patient during 40 days of hospitalization. Results: After 40 days of hospitalization, her symptoms were reduced, and the blood test results improved. Conclusion: This case presents the therapeutic potential of Korean medicine in the treatment of kwashiorkor.