• 한국태양에너지학회 논문집
• /
• 제23권2호
• /
• pp.91-98
• /
• 2003

Experimental study for a porous aluminum heat dissipator/or heat sink made by casting method is conducted to evaluate the performance of the porous aluminum heat sinks. The parameters applied for the present study are the manufacturing method. various bonding materials for the bottom plate of heat sink, and their different material, pore size, etc.. The casting method for porous aluminum heat sink is suggested for the best performance of heat dissipation in this experiment. The bottom plate applied by melting aluminum is introduced and proved their excellent characteristics compared with brazing, soldering, and bonding methods. In the present experiment, aluminum with different conductivities, such as AC8A and pure aluminum, are tested and the pure aluminums with the higher conductivity than AC8A shows their improvement of the performance. And the proper dimensions related to the pore size and the height of porous aluminum heat sinks are proposed in the present study.

• Journal of Welding and Joining
• /
• 제18권2호
• /
• pp.239-239
• /
• 2000

Automobile manufacturers have employed resistance spot welding(RSW) to join steel sheets for structural rigidity o automobile body. Driven by the need to reduce weight and fuel consumption, car companies have been evaluating aluminum intensive vehicles(AIVs) as a way to reduce vehicle weight without downsizing. During the transition from all steel-construction vehicle body to aluminum intensive body, joining aluminum to steel sheets emerges as a serious contender in automobile body. This paper deals with application of transition material to RSW aluminum to steel. Placing transition material insert between the aluminum/steel interface was found very effective to overcome incompatibility between aluminum and steel. Use of transition insert allows for two separate weld muggets to be formed in their respective aluminum/ aluminum and steel/ steel interfaces. This RSW process was monitored with the aid of dynamic resistance sampling. Typical patterns in sampled dynamic resistance curves indicated formation of sound nugget. (Received February 28, 2000)

• Journal of Welding and Joining
• /
• 제18권2호
• /
• pp.112-118
• /
• 2000

Automobile manufacturers have employed resistance spot welding(RSW) to join steel sheets for structural rigidity of automobile body. Driven by the need to reduce weight and fuel consumption, car companies have been evaluating aluminum intensive vehicles(AIVs) as a way to reduce vehicle weight without downsizing. During the transition from all steel-construction vehicle body to aluminum intensive body, joining aluminum to steel sheets emerges as a serious contender in automobile body. This paper deals with application of transition material to RSW aluminum to steel. Placing transition material insert between the aluminum/steel interface was found very effective to overcome incompatibility between aluminum and steel. Use of transition insert allows for two separate weld nuggets to be formal in their respective aluminum/aluminum and steel/steel interfaces. This RSW process was monitored with the aid of dynamic resistance sampling. Typical patterns in sampled dynamic resistance curves indicated formation of sound nugget.

• 공업화학
• /
• 제17권4호
• /
• pp.335-342
• /
• 2006

금속 알루미늄의 낮은 환원전위는 전기화학적 산화반응을 통하여 알루미늄과 그 표면에 존재하는 산화막의 구조 및 성질의 변화를 일으킨다. 산성용액에서 알루미늄을 전기화학적으로 에칭하여 표면적을 확대시키고 중성의 용액에서 알루미늄 표면에 치밀한 유전체 산화막을 형성시켜 커패시터의 전극으로 이용하고 있다. 저온의 산성용액에서는 양극산화시 나노크기의 다공층 산화막이 형성되며, 나노구조체의 템플레이트로 사용되고 있다. 이와같은 알루미늄의 전기화학적 특성은 알루미늄을 새로운 기능성을 가진 재료로 변화시킴으로서 다양한 분야에서 응용될 것으로 기대된다.

• 한국자동차공학회논문집
• /
• 제13권5호
• /
• pp.50-56
• /
• 2005

Aluminum member absorbs energy by stable plastic deformation under axial loading. While CFRP(Carbon Fiber Reinforced Plastics) member absorbs energy by unstable brittle failure but its specific strength and stiffness is higher than those of aluminum member. In this study, for complement of detects and synergy effect by combination with the advantages of each member, the axial collapse tests were performed for aluminum CFRP members which are composed of aluminum members wrapped with CFRP outside aluminum circular members. Based on the respective collapse characteristics of aluminum and CFRP members, crushing behavior and energy absorption characteristics were analyzed for aluminum CRRP members which have different CFRP fiber orientation angle and thickness Test results showed that aluminum CFRP members supplemented the unstable brittle failure of CFRP members due to ductile nature of inner aluminum members. It turned out that the CFRP fiber orientation angle and thickness influence energy absorption capability together with the collapse mode of the members.

• 한국재료학회지
• /
• 제28권9호
• /
• pp.495-498
• /
• 2018

Intermetallic compound matrix composites have been expected to be established as high temperature structural components. $Ni_3Al$ is a representative intermetallic alloy, which has excellent ductility even at room temperature by adding certain alloying elements. $Ni_3Al$ matrix composites with aluminum oxide particles, which are formed by the in-situ reaction between the alloy and aluminum borate whiskers, are fabricated by a powder metallurgical method. The addition of aluminum borate whiskers disperses the synthetic aluminum oxide particles during sintering and dramatically increases the strength of the composite. The uniform dispersion of reaction synthesized aluminum oxide particles and the uniform solution of boron in the matrix seem to play an important role in the improvement in strength. There is a dramatic increase in strength with the addition of the whisker, and the maximum value is obtained at a 10 vol% addition of whisker. The $Ni_3Al$ composite with 10 vol% aluminum oxide particles $0.3{\mu}m$ in size and with 0.1 wt% boron powder fabricated by the conventional powder metallurgical process does not have such high strength because of inhomogeneous distribution of aluminum oxide particles and of boron. The tensile strength of the $Ni_3Al$ with a 10 vol% aluminum borate whisker reaches more than twice the value, 930 MPa, of the parent alloy. No third phase is observed between the aluminum oxide and the matrix.

• 한국펄프종이공학회:학술대회논문집
• /
• 한국펄프종이공학회 1999년도 Pre-symposium of the 10th ISWPC Recent Advances in Paper Science and Technology
• /
• pp.239-244
• /
• 1999

aluminum sulfate (alum) as a representative retention aid in papermaking processes was added to pulp suspensions, and the aluminum components adsorbed on the pulp were investigated quantitatively by two types of X-ray elementary analyses with regard to simultaneous changes of their surface charges. X-ray photoelectron spectroscopy (XPS) and X-ray fluorescence analysis (XFA) were applied to determine the aluminum components retained in pulp pads up to ca. 10 nm and 100${\mu}$m depth, respectively. In other words, XPS was utilized to analyze the outermost surface layers of the samples, and XFA was available for measurement of their extensive regions. A particle charge detector (PCD) was used to monitor streaming potentials at various pHs of the pulp mixtures under moderate sharing conditions. At pH 4.5 of pulp suspensions containing alum, surface charges of pulp fibers varied from negative to slight negative (approximately neutral) according to adsorption of aluminum components onto the pulp fibers. Subsequently, when a dilute NaOH solution in limited amounts was added to pulp mixtures, both streaming potentials and surface aluminum content of the pulp fibers increased distinctly although little total aluminum retention increased. Further addition of alkali solutions brought drastic decreases of the surface charges and surface aluminum content, while total aluminum content, on the contrary, increased gradually under neutral conditions. These results indicate that residual aluminum ions remained in pulp suspensions are predominantly adsorbed on surfaces of pulp fibers by adequate alkali additions and they must sufficiently cationize the fiber surfaces with increases of somewhat cationic aluminum complexes formed on the surfaces. On the other hand, aluminum components formed in higher pH ranges have nearly no contribution to improvement of charge properties of the pulp fiber surfaces, even though aluminum retention in pulp pads increases. XPS and XFA analyses combined with streaming potential measurement using a PCD suggest close relationships between aluminum content on the pulp fiber surfaces and their charge properties.

• 한국환경과학회지
• /
• 제24권4호
• /
• pp.549-554
• /
• 2015

This study was conducted to determine the effects of mixed Korean red ginseng marc with aluminum sulfate on gas concentration and volatile fatty acid (VFA) in poultry litter during 4 weeks in terms of livestock and environment managements. A total of 240 broiler chicks were randomly allocated to four treatments in four replications and 15 birds per replicate. The four treatments was mixed to rice hull under each pen at 0, 10 g or 20 g red ginseng marc + 90g aluminum sulfate, and 100g aluminum sulfate per kg poultry litter (rice hulls). Carbon dioxide, methane, acetic acid, and propionic acids were measured weekly. The results that could be available include: First, during the experimental period, carbon dioxide emissions were not remarkably different among treatments. Second, no differences were observed among treatments in methane emissions at 2 weeks through 4 weeks, but at 1 week, the reduction in methane emissions was in following order: 100 g aluminum sulfate > 20 g red ginseng marc + 90 g aluminum sulfate > 10 g red ginseng marc + 90 g aluminum sulfate > control. Third, in spite of statistically differences, treatment with 10 g or 20 g red ginseng marc + 90g aluminum sulfate, and 100g aluminum sulfate reduced acetic acid and propionic acid as a function of time, except acetic acid in aluminum sulfate treatment at 2 and 4 weeks. In conclusion, the results indicated that like aluminum sulfate, using 10 g or 20 g red ginseng marc with aluminum sulfate was effective in decreasing methane and propionic acid released from poultry litter.

• 한국식생활문화학회지
• /
• 제25권6호
• /
• pp.839-846
• /
• 2010

본 연구는 농도를 달리한 알루미늄 급여가 두충의 효과에 미치는 영향을 실시한 결과 식이섭취량에서 두충차 추출액과 알루미늄 병합급여군은 알루미늄 단독급여군에 비하여 증가하였으나 각 실험군간에 유의성은 나타나지 않았다. 음용수 섭취량은 알루미늄 단독 급여군에 비하여 알루미늄과 두충차 추출액 병합급여군이 약간 증가하였다. 체중 증가량은 대조군과 두충차 추출액 급여군에 비하여 농도를 달리한 알루미늄 급여군이 감소하였으며 식이효율은 각 실험군간에 유의적인 차이는 나타나지 않았다. 간, 심장, 신장, 폐, 위, 소장, 대장 및 비장 조직 중의 알루미늄 함량에서 대조군과 두충차추출액급여군 간에는 별다른 차이를 보이지 않았으나 각각의 농도를 달리한 알루미늄 급여군에 비하여 알루미늄과 두충차 추출액 병합급여군의 함량은 감소하였다. 레닌활성도에서 대조군에 비하여 두충차 추출액 급여군이 감소하였고, 각각 농도를 달리한 알루미늄 급여군에 비하여 알루미늄과 두충차 추출액 병합급여군이 유의적으로 감소하였다. 알도스테론농도는 각각 농도를 달리한 알루미늄 급여군에 비하여 알루미늄과 두충 추출액 병합급여군이 유의적으로 감소하였다. ALT와 AST는 농도를 달리한 알루미늄 단독 급여군에 비하여 알루미늄과 두충차 추출액 병합 급여군이 유의적으로 감소하였다. LDHase는 알루미늄 급여군에 비하여 알루미늄과 두충차 추출액 병합급여군이 감소하였으나 유의한 차이는 없었다. ChEase는 농도를 달리한 알루미늄 단독급여군에 비하여 두충차 추출액과 알루미늄 병합급여군 및 대조군과 두충차 추출액군이 유의하게 증가하였다. 따라서 알루미늄을 만성적으로 섭취하게 되면 독성효과를 나타낼 수 있으나 두충차추출액이 알루미늄에 의해 손상된 조직과 AST, ALT, LDHase. ChEase 활성도, 레닌, 알도스테론 호르몬 농도에 어느정도 영향을 미치는 것으로 나타나 두충의 폴리페놀 성분이 알루미늄에 의한 어느 정도 중독 완화 효과가 있으며, 본 실험은 흰쥐를 이용한 동물모델로 실시하였으나 알루미늄은 여러 경로를 통해 사람에게 노출 될 수 있으므로 알루미늄이 인체에 어떤 영향을 미치는지에 대한 연구는 계속되어져야 한다고 사료된다.

• 자원리싸이클링
• /
• 제10권5호
• /
• pp.8-15
• /
• 2001

알루미늄드로스는 드로스의 특성과 처리 후 용도를 고려하여 재활용하여야 한다. 본 연구에서는 국내 재생 알루미늄업체에서 발생된 알루미늄드로스를 수산화알루미늄의 원료로 재활용하고자 하였다. 드로스 시료를 크기에 따라 선별하고, $850mu$m 보다 작은 크기의 드로스를 수산화나트륨 용액으로 침출하여 드로스 중의 잔류 알루미늄을 용액 중으로 분리 추출하고, 침출용액에서 석출반응에 의하여 수산화알루미늄 침전물을 회수하였다. 시험 제조한 수산화알루미늄의 순도는 98% 이상이었고, 입경은 $3~39\mu$m 범위였다. 또한, 침출시 드로스의 장입량, NaOH 농도 및 광액농도가 수산화알루미늄의 회수율에 미치는 영향을 조사한 결과 폐드로스를 A/C비 0.5, 광액농도 14~16%로 침출하는 것이 석출시 회수율이 가장 높았다. 본 연구결과를 알루미늄드로스 재활용의 한 가지 방법으로 제안하고자 한다.