In this study, we investigate the recycling of aluminum-based metal matrix composites(AMCs) embedded with SiC particulates. The microstructure of the AMCs is characterized by X-ray diffraction and scanning electron microscopy. The possibility of recycling the composite scrap is attempted from the melted alloy and SiC particulates by re-melting, holding and solidification in crucibles. The recovery percentage of the matrix alloy is calculated after a number of holding times, 0, 5, 10, 15, 20, 25 and 30 minutes and for different particulate sizes and weight fractions in the Al matrix. The results show that the recovery percentage of the matrix alloy, as well as the time required for maximum recovery of the matrix, is dependent on the size and weight fraction of SiC particulates. In addition, the percentage recovery increases with particulate size but drops with the particulate fraction in the matrix. The time to reach maximum recovery falls rapidly with an increase in particulate size and fraction.

Modern business trends call for miniaturization of electronic systems. One of the major impedances in this miniaturization is the conductive and inductive components in chips and circuit boards. Direct Write Technology can write these soft magnetic materials, thus allowing for further miniaturization of inductor devices. Another obstacle in electronics fabrication is the size limitations of thick screen-printing and the material limitations in ink jet printing. Direct Write Technologies address both of these limitations by providing feature sizes less than 20 microns with a wide range of materials possibilities. A discussion of the application of these nano-particulate materials by Direct Write Technologies will be presented.

원자력연구시설의 핫셀 내 바닥이나 장치표면에 부착된 고방사능분진의 제거를 위해서 PFC제염기술을 적용한다. 고가인 PFC 용액의 재사용을 위해서는 여과장치의 개발이 필요하고 제염종료 후 이차폐기물의 양을 최소화할 필요가 있다. PFC 제염폐액 내 방사성 입자를 제거하기 위해 핫셀 내의 고방사능분진의 오염 특성을 조사했다. 여과 막을 이용한 입자의 제거효율 측면에서 보면 세라믹 , PVDF, PP 막 모두가 95 이상의 높은 여과 성능을 보였다. 기공 크기가 같은 동일 여과 막에서는 입자가 크거나 가하는 압력이 높을수록 좀더 높은 제거효율을 나타내었고, 3psi이하에서는 PVDF의 제거효율이 다른 막에 비해 작게 나타났다. 플럭스 성능은 PVDF 막이 가장 높은 수준을 나타냈고 세라믹과 PP 막에서는 다소 낮은 성능을 보였다. PVDF 막은 낮은 압력과 짧은 여과시간으로 최대(한계)플럭스에 도달함을 확인하였다. 세라믹 막은 모의입자의 제거 효율은 높지만 다소 낮은 Flux 성능을 나타냈다. 또한, 막 자체의 비싼 가격과 쉽게 부서지는 성질의 단점을 지니고 있지만 무기화합물의 재질로 되어있기 때문에 알파방사능 환경에서 H, 가스를 발생하는 고분자 막인 PVDF, PP 막과 비교하여 훨씬 안정적이었다. 그리고 이들 소수성 여과막들의 특성 비교를 바탕으로 세라믹 막을 적용한 PFC 실증 여과장치의 공정도를 살펴보았다.

The PC game rooms in Korea have a problem in the aspect of indoor air quality because there are many occupants for 24 hours where the smoking is allowed. This study was carried out to evaluate indoor air quality (IAQ) including the size distribution of respirable suspended particulates (RSP) and airborne nicotine concentration in selected PC game rooms. The subjects are 6 PC game rooms in Seoul and Sung-Nam Cities. In this study, airborne RSP and nicotine concentrations were measured during a period from February to March, 2003. Significant correlation has been found between the concentrations of RSP and nicotine in PC game room. Also the negative correlation was found between room area and number of operating fan. The correlation coefficients between RSP size distribution and nicotine concentration were 0.868, 0.866, 0.870 in the stages 2 (cut-point 14.80㎛), 5 (cut-point 3.50㎛), and 8 (cut-point 0.52㎛) from Marple's 8-stage cascade impactor, respectively. In conclusion, RSP concentration in PC game room has a tendency to increase by smoking. Therefore, it is suggested that the effective air control system and education program be applied for PC game room.

In this paper the failure mechanisms of polypropylene resin composites filled with calcium carbonate particulates have been studied in the temperature range -50℃ to -50℃ The fillers used are both untreated and surface treated with stearic acid. The impact fracture toughness is evaluated from the impact energy absorbed divided by the uncut ligament area of the specimen. Impact fracture toughness increases as temperature is raised whether the fillers are coated or not. The static fracture toughness of these particular composites is evaluated based on the linear clastic fracture toughness of these particular composites is evaluated based on the linear clastic fracture mechanics. Static fracture toughess decreases with increasing temperature whether the fillers are coated or not. An extended stress whitened zone are observed through a large number of availabel sites for cavitation/debonding along particle matrix interface and matrix deformation.

East Asia is characterized by anthropogenic emissions resulting from the large population and fast economic growth of this region. Since the prevailing wind is westerly and northwesterly, emissions from Ul-jin can be expected to contribute to acidic deposition increase in downwind direction. Aerosols collected at the near coast site, Uljin geun, gyungbook and were analyzed for NH4 +, Mg2+, Na+, Ca2+, Cl-, SO4 2-, and NO3 - from Aug. 2012 to Feb. 2013. The seasonal averaged aerosol concentration showed the highest potassium and calcium ion in winter and the highest ammonium ion due to a meadow and high solar intensity in summer. Sodium and chloride ion showed the same ratio all seasons and sulfate and nitrate species showed the maximum value in winter Chemical components of aerosols collected at the near coast site, Uljin geun, gyungbook were lower by 16 to 73% than those collected at other similar environment site such as kanghwa, yangyang. Comparing air quality data at the near coast site, Uljin geun, gyungbook, There was found that Uljin coast site is less influenced by the sea salts(potassium, magnesium, calcium) and nss-SO4 2- percentage is 3~13% higher than similar condition site.

This study was performed at Sa-Sang Industrial area in Pusan City. To measure the total suspended particulates(T.S.P) and SO_3 following places was selected industrial area, down town, residentail area. T.S.P was collected on glass filters by High-Volume Air Sampler, SO_3 was measured by PbO_2 candle method The collected T.S.P was analyzed for various anion(for example, NO_3, SO_4, PO_4, F, Cl) by Ion Chromatography, and Pb by Inductively Coupled Plasma.

The concentration of Total Suspended Particulates(T.S.P), size distribution of suspended particulates, and soluble anions of T.S.P in atmosphere of industrial region in Busan were investigated. T.S.P was measured by High-Volume Air Sampler and particle size distribution was measured by Andersen Air Sampler. We analyzed the chemical component of the T.S.P by Ion Chromatography and measured the shape and size of T.S.P by Scanning Electron Micrography. The small size of T.S.P mainly exist in industrial region, but the large size of T.S.P mainly exist in residentail area.