• 농업생명과학연구
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• 제44권4호
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• pp.29-43
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• 2010

The numerical analysis by using CFX 11.0 commercial code was done for proper design of the heat exchanger. The present experimental studies were also conducted to investigate the effects of circulating solid particles on the characteristics of fluid flow, heat transfer and cleaning effect in the fluidized bed vertical shell and tube type heat exchanger with counterflow, at which a variety of solid particles such as glass ($3mm{\Phi}$), aluminum ($2{\sim}3mm{\Phi}$), steel ($2{\sim}2.5mm{\Phi}$), copper ($2.5mm{\Phi}$) and sand ($2{\sim}4mm{\Phi}$) were used in the fluidized bed with a smooth tube. Seven different solid particles have the same volume, and the effects of various parameters such as water flow rates, particle diameter, materials and geometry were investigated. The present experimental and numerical results showed that the flow velocity range for collision of particles to the tube wall was higher with heavier density solid particles, and the increase in heat transfer was in the order of sand, copper, steel, aluminum, and glass. This behavior might be attributed to the parameters such as surface roughness or particle heat capacity.

• Journal of Pharmaceutical Investigation
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• 제21권3호
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• pp.155-160
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• 1991

Particulate is the foreign insoluble material in injectable solution inadvertently present in a given product. Considerable efforts have been made to avoid or minimize particulate contamination by pharmaceutical manufacturers during the production of parenteral products. Particulate contamination of the parenteral products can occur mainly during the opening (cutting) the container immediately before clinical use. In this study, particulate contamination generated during the opening process of ampoules (conventional type, 1-point and color-break ampoules) was compared with that of a prefilled injectable container (prefilled syringe). The particles were examined under a microscope after filtration of the total fluids in the containers. Particles having wide range of size distribution were found from all the ampoules tested. The contamination from the I-point ampoule and colorbreak ampoule was much less than from the conventional ampoule. Glass particles generated by cutting the glass-made ampoules seemed a principal source of the particulate contamination. The glass-partiaulte contamination could be improved substantially by replacing the ampoule containers with the prefilled syringe. Prefilled syringe, which can be used without any cutting process. did not generate particulates during the use. Therefore, it was concluded that prefilled syringe is most preferable container for the small volume parenteral (SVP) fluids in terms of particulate contamination.

• 한국정밀공학회지
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• 제31권9호
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• pp.831-838
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• 2014

Chip on glass (COG) bonding using anisotropic conductive film (ACF) is a key technology to assemble a driver IC onto a LCD glass panel. In this paper, an experimental investigation was conducted to investigate the correlation between contact resistance and characteristics of image taken by machine vision based inspection system. The results show that the contact resistance was strongly influenced by the contrast ratio of conductive particle rather than the number of conductive particles. Also, number of conductive particles whose contrast ratio is below 0.75 is crucial for determining the quality of the assembled samples. On the other hand, in the result of high temperature high humidity storage test, the contrast ratio of samples was increased. However, in the case of open-circuit samples after temperature humidity storage test, the number of conductive particles whose contrast ratio is above 0.75 was more than that of the closed-circuit samples.

• Design & Manufacturing
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• 제14권1호
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• pp.36-41
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• 2020

Recently, due to the development of MEMS technology, researches for the production of effective micro structures and shapes have been actively conducted. However, the process technology based on chemical etching has a number of problems such as environmental pollution and time problems due to multi-process. Various processes to cope with this process are being studied, and one of the mechanical etching processes is the powder blasting process. This process is a method of spraying fine particles, which has the advantage of being an effective process in manufacturing hard brittle materials. However, it is also a process that adversely affects the material surface roughness and material properties due to the impact of the injection of fine particles. In this study, after fabricating micro-channels in fused silica glass with excellent optical properties among the hard brittle materials, we used the nano indentation system to analyze the micro parts using nano-particles as well as machinability and surface roughness analysis of the processed surface. The analysis was performed for the effective processing of powder blasting.

• Applied Microscopy
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• 제25권1호
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• pp.130-138
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• 1995

TEM specimen preparation methods have been examined to characterize Cu oxide particles in the polyimide film. Polyimide films were prepared by coating polyamic acid onto Cu films which had been deposited on TEM-mask and glass substrates and Cu foil, followed by thermal curing. In case of TEM-mask, direct observation was possible without further preparation. In other cases, TEM specimen were made by separating polyimide film from the substrate. Polyimide films were removed from glass and Cu foil by dissolving glass in HF solution and Cu foil in $H_{2}SO_{4}$ solution. TEM-mask observation confirms that fine $Cu_{2}O$ particles precipitate in the polyimide as a result of reaction of polyamic acid with Cu. However $Cu_{2}O$ particle reacts with HF and $H_{2}SO_{4}$ solution during dissolving the substrate and interpretation could be misled. It is concluded characterization of $Cu_{2}O$ particle in polyimide using TEM-mask is better than other methods.

• 한국세라믹학회지
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• 제34권4호
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• pp.420-428
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• 1997

Alumino-borosilicate glasses containing nano-sized CuCl crystals for nonlinear optical application were prepared by the melting and precipitation process, and structural and optical properties were investigated by using XRD, TEM, SAXS, and optical spectroscopy. the average radius of the precipitated CuCl particles was about 2 nm. The blue shift of Z3 resonance peak with decreasing the precipitated CuCl particles size was found and the radius increased with decreasing the glass transition temperature of the matrix glass and with increasing the temperature and duration time of the precipitation heat treatment.

• Bulletin of the Korean Chemical Society
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• 제17권8호
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• pp.696-699
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• 1996

Silicate and borosilicate gels were prepared by the sol-gel process and thermally treated in the 150-850 ℃ temperature range. Solid-state 1H MAS and 29Si CP/MAS NMR spectroscopy were used to investigate the effects of heat treatments on the silicate gel to glass conversion process. The 1H NMR isotropic chemical shifts and the relative intensities of hydrogen bonded and isolated silanol groups have been used to access the information concerning the dehydration process on the silicate gel surface. The 29Si NMR isotropic chemical shifts affected by the local silicon environment have been used to determine the degree of crosslinking, i.e. the number of siloxane bonds. These NMR results suggest that the silicate gel to glass conversion process is occurred by two stages which are dependent on the temperature; (1) the formation of particles up to 450 ℃ and (2) the formation of large particles by aggregation of each separated single particle above 450 ℃. In addition, the effects of B atom on the formation of borosiloxane bonds in borosilicates have been discussed.

• International Journal of Aeronautical and Space Sciences
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• 제11권4호
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• pp.360-365
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• 2010

Three phase composite materials are widely used in the shipbuilding industry. When reinforced with fiber and particle, the physical and mechanical properties of polymer composite materials are improved. This paper presents the bending analysis of a three phase composite plate with an epoxy matrix, reinforced glass fiber and titanium oxide particles including creep effect when shear stress is taken into account. The obtained results indicate that creep strains lead to compression in the composite material. Introducing reinforced fibers and particles reduces the plate's deflection, when increasing the stretch coefficient allows the calculation of creep deflection during a long loading period.

• Computers and Concrete
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• 제17권2호
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• pp.255-269
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• 2016

The waste glass sludge is a waste produced in the glass industry. It is in a dust form and disposed with water. In the disposal process, various cohesive agents are incorporated in order to precipitate the glass particles efficiently. In this paper, we investigate the pozzolanic reaction of the waste glass sludge incorporating precipitation additives experimentally. The consumption of calcium hydroxide, the setting time and the compressive strength and the pore structure were tested for two different types of the waste glass sludge depending on whether precipitation additives were used. It was found that the waste glass sludge incorporating the precipitation additives had a higher pozzolanic potential than the reference waste glass sludge without precipitation additives.

• 자원리싸이클링
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• 제28권6호
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• pp.96-105
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• 2019

폐자동차파쇄잔재물(Automobile Shredder Residue, ASR)은 폐차 재활용시 발생되는 최종 폐기물로써 파분쇄, 공기분급, 자력선별 및 정전선별법과 같은 자원처리 공정을 이용하여 선별할 수 있다. 본 연구에서는 유도형 정전선별기를 이용하여 A SR의 선별효율 향상 및 예측을 위한 전도체(구리) 및 비전도체(유리)의 궤적분석이 수행되었다. 전도체의 궤적분석 결과, 0.5와 0.25 mm 조립자 구리선의 모사궤적은 실제궤적과 거의 일치하였다. 반면 0.06 mm 구리선의 관찰궤적은 (-) 전극으로 편향되었다. 이는 입자특성 및 상대습도에 의한 전하량의 영향 때문으로 판단된다. 비전도체의 경우 절연체 유리의 관찰궤적이 전도성 입자들의 궤적과 유사한 특징을 보이면서 (-) 전극으로 편향되었다. 현미경, SEM & EDS 분석결과 유리표면에서 미립의 철과 전도성 유기물과 같은 이물질 발견되었다. 이와 같이 이물질이 부착된 유리는 ASR 재활용을 위한 정전선별시 비철금속의 선별효율을 저하시키는 것으로판단된다. 향후 연구에서 유리에 부착된 이물질 제거를 위한 전처리 기술개발 및 개선된 궤적모사 연구가 요구된다.