• Journal of Powder Materials
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• v.10 no.6
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• pp.383-389
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• 2003

As in other areas of materials technology, the tendency towards light weight constructions becomes more and more important also for powder metallurgy. The development is mainly driven by the automotive industry looking for mass reduction of vehicles as a major factor for fuel economy. Powder metallurgy has to offer a number of interesting areas including the development of sintered materials of light metals. PM aluminium alloys with improved properties are on the way to replace ferrous pars. For high temperature applications in the engine, titanium aluminide based materials offer a great potential, e.g. for exhaust valves. The PM route using elemental powders and reactions sintering is considered to be a cost effective way for net shape parts production. Furthermore it is expected that lower costs for titanium raw materials coming from metallurgical activities will offer new chances for sintered parts with titanium alloys. The field of cellular metals expands with the hollow sphere technique, that can provide materials of many metals and alloys with a great flexibility in structure modifications. These structures are expected to be used in improving the safety (crash absoption) and noise reduction in cars in the near future and offer great potential for many other applications.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.1
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• pp.107-113
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• 2012

Pollutants in aquaculture system effluent mostly originated from solid wastes including uneaten feed and excreta of cultured species. In this research, DAF(Dissolved Air Flotation) unit is suggested as an integrated solid control unit especially as a form of IIBG(Inline Injection Bubble Generation) process in aquaculture system. Solid removal performance of DAF unit was examined under various operation and salinity conditions with turbidity and suspended solid. Solid waste removal efficiencies were found to be affected by operation conditions including saturator pressure, recycle ratio, coagulant concentration. Solid removal efficiency was higher under higher saturator pressure and recycle ratio under which condition larger number of bubbles is generated. Coagulant is thought to have important role in creating bubble-particle aggregate by showing better removal efficiency with higher concentration. However higher saline water showed less effectiveness in removing solids by DAF(IIBG). Application of DAF(IIBG) process also showed additional effect in phosphate removal and DO(Dissolved Oxygen) supply. Phosphate existed in polluted water was removed up to 46% after treatment, which is thought to attribute to aluminium phosphate precipitation. And DO concentration was found to increase over 50% of initial saturation concentration after the injection of micro-bubbles. Through experiments on solid removal from aquaculture effluent, DAF(IIBG) process is estimated to be effective solid control method. This property can help aquaculture system being installed and operated simply and effectively.

• Journal of Trauma and Injury
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• v.27 no.2
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• pp.20-24
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• 2014

Purpose: The temperature of a warm fluid infused into a patient is lowered because the line that allows the fluid to be infused into the patient is exposed to room air. This study evaluated the effects of aluminum foil used as an insulator surrounding the fluid infusion lines when using warm crystalloid fluids to treat traumatic shock patients. Methods: The study measured the differences in fluid temperature between infusion lines with and without the aluminum-foil insulation. We used 1L of normal saline at $40^{\circ}C$ as the infusion fluid, and the fluid infusion line was 200 cm long. The differences in temperature were measured for various fluid flow rates from 12,000 mL/min to 100 mL/min. We performed three experiments at each flow rate. Results: The results showed the differences in temperature between the groups with and without the aluminum insulation were significant for flow rates above 100 mL/min. Conclusion: Hypothermia in trauma patients results in many adverse complications such as peripheral vascular constriction, tissue hypoxia, metabolic acidosis, heart dysfunction and so on. Thus, the use of warm fluids and blood components is essential to reduce the probability of hypothermia. This study showed the aluminum foil wrapped around the infusion line had an insulator effect. As a result, such a wrapping can be used to avoid the adverse effects of hypothermia.

• Journal of Dental Rehabilitation and Applied Science
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• v.28 no.3
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• pp.319-326
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• 2012

For many years, ceramics have been used in fixed prosthodontics for achieving optimal esthetics. but, they have another use as well. Many studies today show ceramics can be used for biomaterials. In the beginning researchers made a start in the study of aluminium oxide and sapphire for biomaterial. The appearance of Zirconia began a new phase of research. Zirconia was introduced into implantology as an alternative to titanium, because of its white color, good mechanical properties and superior biocompatibility. But it is not easy to surface treatment in comparison with titanium. To overcome the limitation, interconnected porous bodies of zirconia were fabricated by sintering technique. And the technique of coating was developed. Therefore, some zirconia implants are currently available. It is thought that Research of biomaterials as a variety of puposes for the use of zirconia is looking very promising. The purpose of this paper reviews are to evaluation of zirconia as biomaterials.

• Journal of the Korea Convergence Society
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• v.9 no.5
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• pp.151-156
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• 2018

In this study, CFRP and metal or nonmetal were bonded with adhesive and the fracture study on this material was carried out. CFRP at the upper side of specimen and metal or nonmetal were assigned at the lower side of specimen by using DCB specimen as the analysis condition. And it was desribed that the structural adhesive were bonded between both upper and lower sides. As this analysis result, the least equivalent stress was shown at the specimen bonded with aluminium. The maximum shear stress was shown to become lowest at the de-bonded CFRP specimen when titanium was used. In conclusion, it was shown that the deformation of specimen became lowest when titanium was used. On the basis of this study result, the esthetic sense can be shown as the fracture data of bonded interface using adhesive are grafted onto the real life.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.337-341
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• 2001

A new method to extract gold from pyrite roster cinder, which combines ultra-fine-grinding with resin-in-pulp, has been studied in this paper. Compared with traditional leaching technology, it can short leaching time, avoid complex filter process, lower sodium cyanide consumption and increase gold recovery by 35%. During leaching, aluminium oxide ball was used as stirred medium, hydrogen peroxide as leaching aid and sodium hexametaphosphate as grinding aid. With the high efficiency and chemistry effect of ultra-fine-grinding, the leaching process was developed and the gold leaching rate may reach 88%. With AM-2 Б resin as abosorber and sulfocarbamide (TU) as eluent, gold was recovered from cyanide pulp by resin-in-pulp. AM-2 Б resin has good adsorbability in cyanide solution(pH=10). It was easy to elude gold from the loaded resin with 0.1㏖/L cholhydric acid and 1㏖/L sulfocabamide. The effect of contact time, temperature and acidity etc. on the gold absorption had been examined with static methods. The results showed that the adsorption and desorption of gold could both reach over 98%. The effects of flow rate of solution on dynamic adsorption and elution of gold had been examined with dynamic methods. Breakthrough curve and elution curve had been drawn in this paper. A mild condition was determined through a number of experiments: leaching time 2 hours, liquid solid ratio 4:1, sodium cyanide 3kg/t, hydrogen peroxide 0.05%, sodium hexametaphosphate 0.05%; adsorption time 30 minutes, temperature 10-3$0^{\circ}C$, resin($m\ell$) solid(g) ratio 1:10, eluent resin ratio 10-20:1, velocity of eluent $1.5m\ell$/min. Under the mild condition, the gold recovery may reach 85%.

• Journal of Technologic Dentistry
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• v.27 no.1
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• pp.9-17
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• 2005

The use of titanium alloys as biomaterials is increasing due to their superior biocompatibility and enhanced corrosion resistance compared to conventional stainless steels and cobalt-based alloys. Ti-6Al-4V ($\alpha+\beta$type) alloy instead of pure titanium ($\alpha$type) is being widely used as biomaterials has some characteristics such as high fatigue strength, tensile strength and corrosion resistance. But it has been reported recently that the vanadium element expresses cytotoxicity and the aluminium element is related with dementia of Alzheimer type and neurotoxicity. In order to overcome their detrimental effects, $\beta$-phase stabilizer Nb was chosen in the present study. This paper was described the influence of phase changes of Ti-Nb alloys on mechanical properties. Ti-3wt.%Nb($\alpha$type),Ti-20wt.%Nb($\alpha+\beta$type) and Ti-40wt.%Nb($\beta$type) alloys were melted by vacuum arc furnace. The specimens were homogenized at 1050$^{\circ}C$ for 24hr and were then hot rolled to 50% reduction. Each alloys were solution heat treated at $\beta$ zone and $\alpha+\beta$ zone after homogenization and then were aged. The mechanical properties of Ti alloys were analysed by hardness test, tensile test, elongation test and SEM test. The results can be summarized as follows: 1) The higher hardness value of $\alpha+\beta$type alloy was obtained compared to the, $\alpha,\beta$type alloys. 2) The aged treated showed better hardness compared to the solution heat treated, homogenized. 3) In the case of solution and aging treatment at $\beta$region, the $\alpha+\beta$type alloy showed the most highest tensile strength and $\beta$type alloy showed the best elongation.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.6
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• pp.124-129
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• 2002

KAISTAT-4 is the fourth experimental microsatellite of KITSAT series which has been developed by Satellite Technology Research Center of KAIST for the last two years. The launch of KAISTSAT-4 is scheduled in 2003. The primary experimental payloads consist of Far-ultraviolet Imaging Spectrograph and Space Physis Package. In a similar way to KITSAT series, the interior of KAISTSAT-4 comprises mainly a set of stacked aluminium-alloy module boxes, each being capable of acting as the primary load path in the mechanical structure. The KAISTSAT-4 qualification model is now designed, fabricated, integrated, and tested to verify if the electrical and mechanical components work and can withstand the launch environments. All the required structural tests have been performed to a sufficient degree to satisfy the intent of the test requirements. This paper presents the structural system and launch environmental test results of KAISTSAT-4 qualification model.

• Fire Science and Engineering
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• v.24 no.2
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• pp.21-30
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• 2010

We have test chemical resistance and flame retardant properties of chemical protective clothing Fabrics by the ASTM and ISO standard methods. The flame retardant test results show that polyethylene is poor in flame resistance but fluoroelastomer add to decabrom is excellent in flame resistance. Especially, nowadays heat protective clothing for firefighters, which is aluminized film layers laminated to aramid fabric, show the excellent flame resistance. However, the chemical resistance test results show that aluminium is high corrosive in 4M NaOH solution alone. The problem of corrosion can be overcome by employing multiple barrier film. Also, based on the result of flame retardant test, duel skin of polymer barrier film add to aluminum film and single skin of fluorinated rubber with flame retardant materials seems to be fit for the chemical protective clothing. Also the thermal protection and heat transfer test results show that TPP and HTI is increased assured that the continued study on fire risk assessment & chemical resistance of chemical protective clothing fabrics will contribute to the upgrade the performances of chemical protective clothing fabrics.

• Clean Technology
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• v.5 no.2
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• pp.45-52
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• 1999

Recycling of red mud from the aluminium manufacturing process was investigated to be utilized as plastic fillers. High density polyethylene(HDPE), low density polyethylene(LDPE) and polypropylene(PP) were found to be the suitable plastic material for which red mud can be used as fillers. With the addition of red mud the plastic showed red brown color. As the ratio of amount of red mud to plastic increased, the tensile strength increased while the Izod impact strength decreased. About five percent of ethylene vinyl alcohol(EVA) was needed as an additive to prevent the lowering of impact strength. Maleic anhydride modified polypropylene was effective for reduction of impact strength lowering of PP. Mixed waste plastics containing LDPE, HDPE, PP, polystyrene and ABS could also accommodate red mud as fillers. In this case, significant loss in mechanical properties were observed due to immiscibility between the components. Ethylene propylene rubber(EPR) and styrene butadiene styrene block copolymer (SBS) could be used to improve the impact properties of the commingled waste plastics.