• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.16 no.4
• /
• pp.108-112
• /
• 2007

This study analyzes the dynamic fracture phenomenon that aluminum rod impacts aluminum plate or rigid plate and deforms. The value of von-Mises stress in the instance that aluminum rod deforms on rigid plate after contact becomes 1.3 times as large as that in the instance of contact. On the contrary, the value of von-Mises stress in the instance that aluminum rod goes through aluminum plate after contact becomes 0.7 times as small as that in the instance of contact. The value of internal energy in the instance that aluminum rod contacts aluminum plate becomes 2.3 times as large as that in the instance that aluminum rod contacts rigid plate. But the value of kinetic energy in the instance that aluminum rod contacts aluminum plate becomes 0.9 times as small as that in the instance that aluminum rod contacts rigid plate. The value of internal energy in the instance that aluminum rod goes through aluminum plate after contact becomes 0.7 times as small as that in the instance that aluminum rod impacts rigid plate and deforms. And the value of sliding energy in the instance that aluminum rod contacts aluminum plate becomes 0.2 times as small as that in the instance that aluminum rod contacts rigid plate. The value of total energy in case that aluminum rod impacts aluminum plate becomes 0.9 times as small as that in the case that aluminum rod impacts rigid plate.

• Resources Recycling
• /
• v.18 no.4
• /
• pp.38-43
• /
• 2009

The synthesis of aluminum oxalate, one of the aluminum organic compounds, has been performed using aluminum hydroxide as a raw material. For this aim, domestic aluminum hydroxide of 99.7% purity was dissolved by oxalic acid to produce an aqueous aluminum solution. As a result, it was found that aluminum hydroxide could be dissolved almost completely by the reaction with 1.0 mole/l oxalic acid solution at $90^{\circ}C$ for 16 hr. It was strongly required to keep the ratio of ethanol/Al solution more than 2.0 for the synthesis of aluminum oxalate from the aluminum solution. Furthermore, the pH should be controlled to be more than 8.2 in order to obtain the recovery of aluminum oxalate higher than 90%. From the chemical analysis of aluminum oxalate prepared in this work, the content of $NH_4$, Al and C was found to be 14.5, 7.18 and 17.4%, respectively. Accordingly, the aluminum oxalate synthesized from the aluminum solution was confirmed to be $(NH_4)_3Al(C_2O_4)_3$ $3H_2O$.

• The Korean Journal of Food And Nutrition
• /
• v.24 no.1
• /
• pp.28-36
• /
• 2011

To investigate the protective effect of omija(Schizandra chinensis Baillon) tea extracts against the aluminum toxicity, Sprague-Dawley rats($100{\pm}10\;g$) were divided into 6 groups consisting of a control group, a 3% Schizandra chinensis Baillon tea plus extract group, a 1,000 and 2,000 ppm aluminum group, and a 1,000 and 2,000 ppm aluminum plus 3% Schizandra chinensis Baillon tea plus extract group. The rats administered aluminum were given 1,000 and 2,000 ppm of $Al_2(SO_4)_3$ dissolved in distilled water. The aluminum content in tissues from rats administered aluminum was lower than in the tissues of rats of administered aluminum plus 3% Schizandra chinensis Baillon tea in the water extract. Aspartate aminotransferase (AST) and alanine aminotransferase(ALT) levels were increased in the aluminum group and lower in the group receiving a 3% extract of Schizandra chinensis Baillon tea. Lactate dehydrogenase(LDHase) was lower in the group receiving a 3% extract of Schizandra chinensis Baillon tea plus aluminum than in the aluminum group. Cholinesterase(ChEase) was higher in the 3% Schizandra chinensis Baillon tea-aluminum group than in the aluminum group. Plasma levels of renin were increased in the aluminum group, compared to the group receiving 3% Schizandra chinensis Baillon tea plus aluminum. Plasma levels of aldosterone were increased in the aluminum group compared with the 3% Schizandra chinensis Baillon tea plus aluminum group. These results suggest that the group receiving Schizandra chinensis Baillon tea in water extract had a lowered level of aluminum accumulation, and it is believed that the Schizandra chinensis Baillon tea plus water had some protective effects against aluminum toxicity when administered in rats, but the mechanism of these effects remains obscure.

• Journal of the Korean Society of Food Culture
• /
• v.24 no.2
• /
• pp.236-243
• /
• 2009

This study was performed to investigate the effects of aluminum sulfate administration on the brain tissues of old rats, when given at different concentrations. The experiment attempted to further ascertain whether aluminum exposure cause Alzheimer's disease. Seventy-five aged Sprague-Dawley rats were divided into five groups; a control group, 2 ppm aluminum sulfate group, 20 ppm aluminum sulfate group, 40 ppm aluminum sulfate group, and 200 ppm aluminum sulfate group, and were kept on the respective diets for 12 weeks. In order to understand the influence of aluminum on the brain, serum aluminum concentrations, phospholipid composition, and catecholamine concentrations were compared between the aluminum-treated groups and the normal group. According to the results, serum aluminum was higher in the aluminum sulfate-treated groups than in the normal group. Within the cortex, catecholamine concentrationes were significantly increased but cerebellum and brainstem tissue were significantly decreased, in the aluminum sulfate-treated groups compared to the normal group. For phospholipid composition, phosphatidyl inositol was significantly increased wherase phosphatidyl choline, phosphatidyl ethanolamine, and phosphatidyl serine were significantly decreased in the aluminum sulfate-treated groups versus the normal group. Based on the data, increased aluminum consumption in experimental animals causes increased serum aluminum levels and catecholamine variation. These phenomena are very similar to conditions of Alzherimer's disease. Therfore, the results of this experiment further suggest that aluminum cause Alzherimer's disease, coinciding with reports that aluminum is a cause of neurofibrilly tangles in the brain.

• Journal of Korean Society of Water and Wastewater
• /
• v.9 no.3
• /
• pp.88-98
• /
• 1995

Several kinds of coagulants such as aluminum sulfate, PAC, PASS are being used to treat drinking water resulting in residual aluminum ions in the water. Recently, it has been reported that high intake of aluminum ion may cause neurological dieseases such as Alzheimer's diesease and presenile dementia. Because of the possible adverse effect, WHO and EEC recommand to regulate residual aluminum. The autorities in Korea also has plan of regulating residual alunimum from 1995. But there is not enough information about the range of residual aluminum ion concentration when the aluminum sulfate, PAC or PASS has been used as a coagulant. Therefore the study has been conducted to find out the range of residual aluminum ion concentration after using aluminum sulfate, PAC, and PASS. Furthermore the effect of turbidity and alkalinity have been investigated. The experimental results are summarized as; 1. Most of the residual aluminum ion concentrations were within $10^{-6}$ and $10^{-5}mole/l$. Three coagulants have not showed any considerable difference in the residual aluminum concentration up to 50 NTU. However PAC has showed the least residual aluminum in high turbidity water over 100 NTU. 2. The low alkalinity water having 25mg/l as $CaCO_3$ has showed less residual aluminum than the water having 50mg/l alkalinity. However, the difference was not significcant. 3. Even the lowest residual aluminum concentration was over 0.05mg/l. Therefore the process to reduce residual aluminum would be necessary in water treatment plants.

• Journal of the Korean Society for Precision Engineering
• /
• v.25 no.8
• /
• pp.51-56
• /
• 2008

Aluminum foam material has unique properties that make them useful in applications to the automobile, construction and railroad industries. In this study, aluminum was plasma-treated using nitrogen gas to improve fracture behavior between aluminum and aluminum foam material. SLS specimens were used for fracture tests. They were performed using plasma-treated and untreated aluminum/aluminum foam specimens. It was shown that the fracture strength and the tincture toughness of aluminum/aluminum foam were improved ${\sim}86%\;and\;{\sim}250%$, respectively when the aluminum was plasma-treated using nitrogen gas.

• Proceedings of the IEEK Conference
• /
• 2001.10a
• /
• pp.202-208
• /
• 2001

Aluminum dross should be recycled in consideration of characteristics of the dross and its reutilization after processing. In this study, aluminum dross generated in the domestic secondary aluminum industry was processed to use it as raw material for producing aluminum hydroxide. Sample dross was classified according to its size. The dross smaller than 1mm was leached with sodium hydroxide solution to extract the remaining aluminum from the dross into the solution, and then aluminum hydroxide precipitate was recovered from the leach liquor. Purity of the obtained aluminum hydroxide was above 98 percent, and particle size of the sample was in range of 3-39${\mu}{\textrm}{m}$. From the result, it was suggested that this process could be applicable to recycling of aluminum dross.

• Journal of the Korean Society for Precision Engineering
• /
• v.21 no.11
• /
• pp.149-154
• /
• 2004

For a present study, we investigated fatigue behavior of cracked aluminum repaired by unidirectional graphite/epoxy composite material. Three different specimens were used in the fatigue tests: cracked aluminum, cracked aluminum repaired by graphite/epoxy composite patch, and plasma-treated aluminum repaired by graphite/epoxy composite patch. The surface of the aluminum was treated using a DC plasma. The results showed that the fatigue crack growth behavior of cracked aluminum was significantly improved by repairing the cracked area with a composite patch. Specifically, the specimen repaired by composite patch showed about 300％ more fatigue lift than the cracked aluminum. In particular, the plasma-treated aluminum repaired by composite patch showed almost 12 ％ more fatigue life than the cracked aluminum repaired by graphite/epoxy composite patch. The increased fatigue life of plasma-treated case was attributed to the surface roughness of aluminum by plasma treatment.

• Resources Recycling
• /
• v.18 no.6
• /
• pp.18-23
• /
• 2009

An investigation on the synthesis of aluminum citrate, one of the aluminum organic compounds, has been performed using aluminum chloride solutions as a starting material. For the synthesis of aluminum citrate, citric acid was added to aluminum solutions with the mole ratio of citric acid to aluminum to be 2.5 and aluminum citrate synthesized was also characterized in terms of chemical analysis, X-ray diffraction, particle size measurement and SEM analysis. As a result, it was found that the ratio of ethanol/Al solution more than 4.0 was required for the synthesis of aluminum citrate from aluminum solutions. Furthermore, the pH should be controlled to be more than 7.0 in order to obtain the recovery of aluminum citrate higher than 97%. From the chemical analysis of aluminum citrate synthesized in this work, the content of $NH_4$, Al and C was found to be 17.0, 4.01 and 25.7%, respectively. Accordingly, the aluminum citrate synthesized from aluminum solutions was confirmed to be $(NH_4)_5Al(C_6H_4O_7)_2{\cdot}2H_2O$.

• Proceedings of the Korean Sanitation Conference
• /
• 2004.11a
• /
• pp.54-65
• /
• 2004

Use of aluminum salts as coagulants In water treatment may lead to increased concentrations of aluminum in finished water. Aluminum is a suspected causative agent of neurological disorders such as Alzheimer's disease. The objective of this study was to examine variation and minimizing in residual aluminum concentration during water treatment process. The aluminum sources at Bokjeong Water Plant were present naturally aluminum in the raw water and derived due to use of PACS as a coagulant. Much of the raw water total aluminum were in particulate and suspended aluminum. In this study was compared the optimize condition to minimize the concentration of residual aluminum using Jar-test with the various coagulants such as alum, PAC, PACS. The results indicated that PACS was more effective than alum, PAC and insufficient or excessive alum, PAC, PACS addition led to increase residual aluminum. Adjustment raw water pH $6.5\~7.0$ before coagulation using PACS was capable of minimizing total and dissolved aluminum. Thus it is important that the optimal dosage of coagulant and the optimal pH adjustment before coagulation can decided to minimize the concentration of residual aluminum in treated water.