• Advanced Composite Materials
• /
• v.18 no.2
• /
• pp.187-195
• /
• 2009

Much attention has been paid to the processing of inorganic whisker, especially calcium carbonate whisker, which can be used as reinforcement materials of polymer composite due to its low price. Unfortunately, the present synthesis technique of calcium carbonate whisker starts from calcinations of limestone, which involves high energy consumption and furthermore is a highly environment polluting reaction. In this report, needle-like aragonite was synthesized with a reversible solution reaction from limestone without calcination. Optical microscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques were used to characterize the morphology and crystal structure of intermediates as well as that of the product, aragonite. GCC (grinding calcium carbonate) powder was dissolved in an aqueous solution of magnesium sulfate with reflux and air flush. EDTA titration was used to evaluate reaction rate of the dissolution. A kinetics equation of the dissolution reaction was constructed, which displayed second-order kinetics with respect to the concentration of magnesium sulfate. A rate constant of $0.0015\;l^{-3}{\cdot}mol^{-1}{\cdot}h^{-1}$ was obtained. The dissolution reaction gave fiber-like magnesium hydroxide sulfate and gypsum crystal. Then needle-like aragonite with a length of $9.13\;{\pm}\;1.02\;{\mu}m$ and an aspect ratio of $5.64\;{\pm}\;1.37$ was synthesized from the dissolution product with $CO_2$ bubbling at $70^{\circ}C$.

• Journal of The Korean Society of Integrative Medicine
• /
• v.8 no.4
• /
• pp.133-142
• /
• 2020

Purpose : The purpose of this study was to investigate the effective recovery method of exercise-induced fatigue and muscle pain by comparing the effect of the use of illite hot mat product and general hot mat product on the recovery of muscle pain induced by high intensity exercise. Methods : To measure and analyze the changes in lactic acid, CRP, and ACR according to the high-intensity circuit training program, this study was conducted for the healthy adult men and women, who exercise st the K-region sports center. A total of 45 subjects were studied in 15 groups of 15 patients who received an illite hot-water mat recovery group (A group), 15 general hot-water mat recovery group (B group), and 15 control group (C group). The circuit training exercise program was conducted as a one-time exercise, and each exercise time consisted of 30 minutes of warm-up exercise, 5 minutes of main exercise, 20 minutes of clean-up exercise, and 5 minutes of strength exercise. The intensity setting was high intensity of subjective exercise intensity It carried out by setting to (14-16RPE). Results : Changes in Lactic Acid Concentration There was a significant difference in the lactic acid concentrations between the groups after the high intensity circuit training program (p <.05). The illite rest group (A) decreased 7.71 mmol / L and the control group decreased 4.03 mmol / L. Significantly decreased (p <.05). Changes in ACR Concentration. There was a significant difference in the ACR concentrations Significant differences were found in CRP and ACR during the recovery period after exercise. (p <.05), the elite rest group (A) decreased 2.47 mg / mmol, and the control group increased 1.63 mg / mmol. There was a significant difference (p <.05). Conclusion: The static rest on a heated mat after high-intensity exercise has an effect on changes in blood lactate and ACR levels.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2006.05a
• /
• pp.1793-1799
• /
• 2006

생산자 폐기 책임 규제 강화로 인하여, 제조업 영역이 제품 제조(BOL) 뿐만 아니라 사용, 보수(MOL)와 폐기(EOL)까지 확장 수명주기로 확대 되고 있다. 또한 EOL상에서 개별 제품에 대한 제품 복원 관리 시스템 (PRMS: Product Recovery Management System)에 관한 연구가 활발히 진행 되고 있다. 그러나 BOL, MOL과 EOL간의 정보 단절 문제, MOL상의 정보를 저장하고 사용할 수 없었던 문제는 EOL관리의 자동화를 저해한 큰 요인이다. 최근 유비쿼터스 기술의 발달로 개별 제품 추적이 가능해 졌지만, EOC 등의 식별부호(ID)만으로는 PRMS에 필요한 제품 정보를 얻을 수 없다. 본 논문에서는 제품 ID로부터 MOL상의 정보를 연결하고, 국제표준 기반 정보모델을 이용하는 PRMS를 개발한다. 이를 위해: (1) PRMS에 필요한 정보를 국제표준(ISO10303-239 등)을 기반으로 모델링하고, (2) 제품 ID를 통해 MOL상의 정보를 수집하여 제품 복원에 대한 의사결정을 수행할 수 있는 PRMS를 설계하고, (3) 시제품 구현을 통해 제안된 데이터 모델 및 시스템의 유효성을 검증한다.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.33 no.3
• /
• pp.366-378
• /
• 2009

The purpose of this study was to understand fashion product consumers' relationship dissolution by considering the characteristics of customer behavior and examining the connection between the main variables. The survey was conducted on 623 women over 20 years old who had experienced relationship dissolution or problems with regular fashion stores in the areas of Seoul and Kyungki in September 2005. The SPSS 12.0 package and Amos program were used to analyze the data. The results of this study were as follows: First, service recovery justice of a fashion store, interactional justice, distributive justice, and procedural justice had effects on encounter satisfaction. Furthermore, encounter satisfaction influenced relationship dissolution behavior, voice, exit, loyalty, neglect via overall satisfaction. Second, there were differences in relationship dissolution behavior according to consumer loyalty and switching costs.

• Journal of the Korea Safety Management & Science
• /
• v.10 no.1
• /
• pp.205-213
• /
• 2008

Servicizing is defined 'not as to sell the products but as to sell the functions'. This study was done on the methods for revitalization as the object items of navigation & antenna among car parts. The direct door-to-door survey was done for 101 enterprises (direct-management stores) and percentage & t-test were done for statistics. The results can be summarized like followings. First, PR on servicizing is required. Second the optimized methods can be obtained by incorporating reuse & recycling distribution systems of servicizing with the existing recovery system Reuse distribution system can be constructed rationally because inventory control is being done correct1y with the periodic recovery. Finally, as for the analysis on the relative importance of main factors of servicizing, it shows that supports & providing the concrete frame of the government & local autonomous body are important.

• Korean Chemical Engineering Research
• /
• v.44 no.2
• /
• pp.129-135
• /
• 2006

In this study, computer modeling and simulation works were performed to obtain nearly pure toluene product from toluene containing non-aromatic compounds using sulfolane as a solvent through an extractive distillation process. NRTL liquid activity coefficient model was adopted for phase equilibrium calculations and Aspen Plus release 12.1, a commercial process simulator, was used to simulate the extractive distillation process. In this study, it was concluded that the toluene product with a purity of 99.8 percent by weight and a recovery of 99.65 percent was obtained through an extractive distillation process.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.39 no.2
• /
• pp.97-109
• /
• 2014

This paper considers a reverse supply chain with simultaneous recovery of used products and manufacturing of brand-new ones. Recovered products are downgraded and have to be sold in a market different from that of brand-new products at a different price. In case of a shortage of recovered product inventory, a brand-new item, if available, can be offered at the price of a recovered product. In other words, one-way demand substitution is allowed. We address the joint decision of when to manufacture brand-new product, when to recover returned product, and how to control demand substitution to maximize the hybrid production system's profits. To this end, we propose a Markov decision Process model and investigate the structure of the optimal policy. Performance comparison is numerically implemented between the models with and without downward demand substitution option under different operating conditions of the system parameters.

• Nuclear Engineering and Technology
• /
• v.40 no.7
• /
• pp.581-592
• /
• 2008

In this study, a conceptual pyroprocess flowsheet has been devised by combining several dry-type unit processes; its applicability as an alternative fuel cycle technology was analyzed. A key point in the evaluation of its applicability to the fuel cycle was the recovery yield of fissile materials from spent fuels as well as the proliferation resistance of the process. The recovery yields of uranium and transuranic elements (TRU) were obtained from a material balance for every unit process composing the whole pyroprocess. The material balances for several elemental groups of interest such as uranium, TRU, rare earth, gaseous fission products, and heat generating elements were calculated on the basis of the knowledge base that is available from domestic and foreign experimental results or technical information presented in open literature. The calculated result of the material balance revealed that uranium and TRU could be recovered at 98.0% and 97.0%, respectively, from a typical PWR spent fuel. Furthermore, the anticipated TRU product was found to emit a non-negligible level of $\gamma$-ray and a significantly higher level of neutrons compared to that of a typical plutonium product obtained from the PUREX process. The results indicate that the product from this conceptual pyroprocessing should be handled in a shielded cell and that this will contribute favorably to retaining proliferation resistance.

• Journal of Korean Society of Forest Science
• /
• v.96 no.2
• /
• pp.197-202
• /
• 2007

This study is conducted to investigate the factors affecting lumber conversion rate of sawmill industry in South Korea. Data were obtained from the survey of 38 sawmills in all geographic regions of South Korea. The variables examined in this study were region, softwood/hardwood log, domestic/imported/both log, the number of power-driven carriages (PDC) installed, the year when and country where PDCs was manufactured, the horse power of PDC, the number of labors required to operate each PDC, the sawing capacity of mill (mill size), and the types of major product and by-products. The lumber recovery factor (LRF) of sawmills were significantly influenced by the origin of logs, level of PDC automation, sawmill size, and size of logs (measured in diameter and length) while not by the location of the mill, types of major product and by-product, log species, and characteristics of PDC. Although these results provide useful information for understanding the technological characteristics of the Korean sawmill industry, further investigation with larger sample is necessary to reveal the more reliable characteristics of sawmill industry in South Korea.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.43 no.1
• /
• pp.65-73
• /
• 2011

The fibrous raw materials in packaging-grade paper production in Korea were mainly obtained from waste paper. The use of recycled paper has both positive and negative impacts in papermaking process. The primary positive impacts are the environmental protection and manufacturing cost reduction, and the negative impacts are the quality reduction in paper quality and the accumulation of heavy metals and other pollutants in wet- and dry-end process. This study was carried out to consider the optimum acid decomposition system with the highest recovery rate for the analysis of heavy metals in packaging-grade paper. The open digestion system using Kjeldahl apparatus and the closed digestion system using microwave oven for decomposing the organic materials in paper were compared. In both open and closed digestion method, the combination of nitric acid, hydrochloric acid and hydrogen peroxide showed higher recovery rate than using only nitric acid alone because the presence of Cl- ions in hydrochloric acid stabilizes ligand formation with metal ions. KOCC was observed to have the highest heavy metal content among the recycled paper samples. The heavy metal contents decomposed with the closed digestion system were relatively higher than with open digestion system.