• 한국산업보건학회지
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• 제10권1호
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• pp.104-114
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• 2000

This study was carried out to estimate current status of dust concentrations in the factories producing non-metallic products in Korea. Data were gathered from the environmental monitoring reports by 40 workplace environmental monitoring institutes and the questionnaire designed for the study by the authors. A total of 1838 dust samples from 368 plants were obtained from the reports and were analyzed with no data modifications. But data on asbestos, rock wool, and welding fumes were excluded in this evaluation. The factories were classified into eight groups according to the standard industrial classification scheme in Korea. The results of this study were as follows; 1. The factories included were glass, non-refractory ceramic, refractory ceramic ware, structural non-refractory clay and ceramic, cement and lime, articles of concretes, and stone. Mean(geometric mean) concentrations of total dust samples ranged from $1.75(0.84)mg/m^3$ to $5.87(2.84)mg/m^3$. Statistically significantly higher dust concentrations were found in the cement and lime industries compared with other industries. 2. The non-compliance rates were 15.2% in glass and 20.6% in other non-metallic mineral products industries. Although all institutions surveyed utilized the identical sampling and classification scheme for dusts as specified in the current occupational exposure limits, wide discrepancies were found in collecting samples and classifying dusts. Further problems were discovered in classifying dusts. A dust sample collected could be classified into any of the three groups regardless of silica content. The results of this study showed that dust concentrations in the non-metallic products industries varied widely. Also discovered was classification errors of dust types among workplace monitoring institutes. These errors could adversely affect the results of exposure assessments and the true nature of dust hazards. Further, no institutions performed respirable dust sampling and analysis of crystalline silica. In order to correct these malpractices, current standards of occupational exposure limits should be revised and tight supervision by the Ministry of Labour be suggested.

• 한국기계가공학회지
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• 제14권2호
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• pp.87-92
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• 2015

The injection molding process is widely used in the production of most plastic products. In order to make metal-colored plastic products like those found in modern luxury home alliances, metallic pigments are mixed with a basic resin material for injection molding. However, process control for metal-colored plastic products is extremely difficult due to the non-uniform melt flow of the metallic resin pigments. In this study, the effect of process parameters on the quality of a metal-colored plastic product is evaluated. A rapid mold cooling method using a compressed cryogenic fluid is also proposed to decrease the content of undesired compounds within the plastic product.

• 대한원격탐사학회지
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• 제7권2호
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• pp.131-147
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• 1991

Feature enhancement combined with some pattern recognition techiques were applied to the Remote Sensing Data for geological mapping with particular emphasis on non-me-tallic ore deposits and their related geologies. The area chosen is north of Ulsan, the size of which is about 400km$^2$. The geology of the area consists mainly of volcanics, volcanic sediments and clastic sediments of Miocene age, underlain by the Kyungsang sediments of Cretaceous age. The mineralization occurs in tuffs or along the bedding plane of tuffaceous sediments, the main products of which are Kaolinite and Bentonite. The outcrops or mine dumps in the study area were most effectively extracted on the histrogram normalized image of TM Band 1 and 2, due to their high reflectivity. These may be confused with some artificial features, like slate roof complex of the poultry farm or cement ground, which should be classified by field checking. Detailed examination of enhancment image combined with pattern recognition techniques made enable to classify different rocks and thereby extract volcanic products which are mainly related to non-metallic ore deposits in the study area.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2000년도 추계학술대회 및 발표대회 강연 및 발표논문 초록집
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• pp.10-10
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• 2000

Mechanical alloying (MA) is a powder metallurgy processing technique involving cold welding, fracturing, and rewelding of powder particles in a high-energy ball mill. This has now become an established commercial technique in producing oxide dispersion strengthened (ODS) nickel- and iron-based materials. The technique of MA is also capable of synthesizing non-equilibrium phases such as supersaturated solid solutions, metastable crystalline and quasicrystalline intermetallic phases, nanostructures, and amorphous alloys. In this respect, the capabilities of MA are similar to those of another important non-equilibrium processing technique, viz, rapid quenching of metallic melts. however, the science of MA is being investigated only during the past ten years or so. The technique of mechanochemistry, on the other hand, has had a long history and the materials produced this way have found a number of technological applications, e.g., in areas such as hydrogen storage materials, heaters, gas absorber, fertilizers. catalysts, cosmetics, and waste management. The present talk will concentrate on the basic mechanisms of formation of non-equilibrium phases by the technique of MA and these aspects will be compared with those of rapid quenching of metallic melts. Additionally, the variety of technological applications of mechanically alloyed products will be highlighted.

• 한국포장학회지
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• 제30권1호
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• pp.43-51
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• 2024

The addition of oxygen scavengers to food products helps to reduce oxygen exposure, thereby mitigating deterioration, including changes in taste, odor, and color, as well as inhibiting microbial growth. Despite the advantages of the existing non-metallic oxygen removal materials in terms of safety for the human body and suitability for use in microwave ovens, their utilization has been limited due to their slow reaction initiation speed. Therefore, in the current study, sodium metabisulfite was impregnated into various porous media, including halloysite nanoclay, activated carbon, montmorillonite, and silica gel. The oxygen scavenger, produced by impregnating silica gel with sodium metabisulfite, demonstrated a 425% improvement in the initial oxygen removal rate compared to pure sodium metabisulfite. Additionally, sachets containing an oxygen-removing composition with an enhanced oxygen removal rate effectively decreased the oxygen concentration to less than 0.5% on the third day of storage in apple packaging, without elevating carbon dioxide levels. Moreover, it proved effective in preventing the browning of the apple surface. Therefore, the SM/SG oxygen-removal composition can be effectively applied to active food packaging by controlling the oxygen concentration within the packaging.

• 에너지공학
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• 제28권3호
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• pp.10-17
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• 2019

국내 친환경 수소차 보급 정책에 따라 수소차와 수소충전소 인프라 개발에 대한 관련 업계의 연구는 활발하게 진행 중이다. 반면에 수소차와 수소충전소의 내구성 및 신뢰성에 직접적인 영향을 주는 기밀용 비금속 소재(라이너, 씰, 개스킷 등)의 위험성 평가 및 재료에 관한 실증 연구는 부족한 실정이다. 이에 본 연구에서는 FMEA를 활용하여 고압 수소 설비에 사용되는 비금속 부품의 라이너와 씰에 대한 위험요소를 도출한 후 심각도, 발생빈도, 검출도 등급을 점수로 환산하여 RPN값을 산정하였다. RPN의 최대값 600, 최소값 63, 평균값이 278.5로 산출되었으며, 라이너와 씰에 대한 주기적인 관리가 중요함을 확인하였다. 더불어 비금속 고무제품에 대한 수소침지와 산소노화시험을 통해 기초 자료로 활용 가능한 물리적 실험값을 제시하고자 하였다.

• 자원리싸이클링
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• 제19권3호
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• pp.9-15
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• 2010

국내 금 광산 폐광미로부터 비금속광물을 분리, 선별하는 공정 중에서 황비철광, 방연광 등이 혼합된 금속광물이 부산물로 회수되며, 이 부산물에는 Au, Pb, As, Fe 성분들이 매우 높게 농축되어진다. 이 부산물로부터 Au의 효율적 회수를 위해서는 우선 금 제련공정에 해로운 거동을 나타내는 금속성분들을 분리, 제거할 필요가 있다. 본 연구에서는 금 광산 폐광미로부터 회수된 금속광물 부산물로부터 Pb, As, Fe등을 제거, 분리하는 실험을 수행하였다. Pb는 알칼리 가압산화침출에 의하여 $120^{\circ}C$, 2M NaOH, 100psi $Po_2$, 250r.p.m., 4 wt.% 고체, 30 min. 침출조건에서 3% 이하 까지 제거시킬 수 있었으며, 침출잔사를 배소 및 자력선별처리하여 As 0.2% 이하, Fe 3% 이하 및 8,000 ppm 이상의 Au 함량을 갖는 비자성산물을 얻을 수 있었다.

• Conservation and Restoration of Cultural Heritage
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• 제1권1호
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• pp.9-22
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• 2012

The most widely excavated iron artifacts used as weapons or farm tools from central southern regions of Korea were subjects of non-metallic inclusion analysis through metallographic examination, microhardness measurement, and scanning electron microscopy with energy dispersive X-ray spectroscopy. Through metallographic interpretation and study of the analyzed results, the steel manufacturing and iron smelting using heat processing in the iron artifacts excavated from the central southern region of the ancient Korean peninsula was studied, and the analysis of the non-metallic inclusions mixed within the metallic structures was interpreted as the ternary phase diagram of the oxide to infer the type of iron ores for the iron products and the temperature of the furnace used to smelt them. Most of the ancient forged iron artifacts showed $Al_2O_3/SiO_2$ with high $SiO_2$ contents and relatively low $Al_2O_3$ contents for iron ore, indicating t hat for $Al_2O_3$ below 5%, it is presumed that magnetic iron ores were reduced to bloom iron (sponge iron) with direct-reduction process for production. The temperature for extraction of wustite for $Al_2O_3$ below 1% was found to be $1,020{\sim}1,050^{\circ}C$. Considering the oxide ternary constitutional diagram of glassy inclusions, the steel-manufacturing temperature was presumed to have been near $1,150{\sim}1,280^{\circ}C$ in most cases, and minimum melting temperature of casting iron part excavated in Daeseong-ri. Gyeonggi was near $1,400^{\circ}C$, and it is thought that hypoeutectic cast iron of about 2.3% carbon was casted and fragility of cast iron was improved by decarburizing in solid state.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 춘계학술대회 논문집
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• pp.107-113
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• 2009

In this study, the importance of failure analysis on large ring forged products was assessed and the process and methodology were introduced. Failure analysis case study of the large ring forged steel product with approximately 10 mm long internal crack found by non-destructive test (NDT) was presented. The micrographic and fractographic observations and the verifying tests were conducted on the cracked specimen to identify the possible metallurgical reason for the defects, and the metallurgical aspects of internal crack formation were discussed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.774-775
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• 2015

In this paper, a series of electromagnetic analyses carried out for a high efficiency 22.9/0.38kV mold transformer are presented. The simulations were performed in order to calculate the losses which eventually verify the performance(efficiency) of the designed product. Here, losses include core loss, stray losses of non-current carrying metallic structural parts(core plate and clamp), ohmic loss and eddy current loss of current carrying metallic parts(busbars, leads, terminals and windings). The obtained results of the simulations were compared to the test results and showed high level of accuracy. The loss evaluation technology will allow designers avoid any potential over-design or under-design of the high efficiency products, reducing the manufacture cost and development period compared to the conventional experience-based design procedures.