• Resources Recycling
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• v.17 no.5
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• pp.28-36
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• 2008

The effect of attrition scrubbing on the recovery of platinum group metals (PGMs) from automobile catalytic converters has been investigated. Catalytic converters were first crushed into particles less than 2 mm and attrition scrubbed in the range of 60 min, and then they were sieved with several screens. The catalyst layer, $\gamma$-alumina, was dislodged from the surface of the supporting matrix into fine particles less than $45{\mu}m$ by attrition scrubbing. The fraction of fine particles less than $45{\mu}m$ increased as the residence time for attrition scrubbing increased. The composition of the fine fraction obtained at a residence time of 40 min was $CeO_2$ 19.3%, $ZrO_2$ 1.9% and PGMs 419 ppm. In the fine fraction, the recovery of y-alumina increased proportionally to the residence time. Simultaneously, the recovery rates of $CeO_2$, $ZrO_2$ and PGMs increased to 82.9%, 78.7% and 78.9%, respectively. The production of the fine fraction less than $45{\mu}m$ and the recovery of $\gamma$-alumina increased when the solid concentration and initial feed size increased. Therefore, the attrition scrubbing as the comminution and separation process was concerned to be effective for the recovery of catalyst layer from ceramic supporting matrix by physical impact and shearing action between particles in the scrubbing vessel.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.4
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• pp.581-587
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• 2003

This study was designed to examine the effect of icroencapsulated iron fortified drink yogurt and vitamin C as a bioavailable helper of iron on chemical and sensory aspects during 20 d storage. Coating material was polyglycerol monostearate (PGMS), and ferric ammonium sulfate and vit C were selected as core materials. The highest efficiency of microencapsulation of iron and vit C were 73% and 95%, respectively, with 5:1:50 ratio (w/w/v) as coating to core material to distilled water. Iron fortification did not affect the fermentation time required for the drink yogurt to reach pH 4.2. The addition of uncapsulated iron decreased the pH during storage. TBA absorbance was significantly lower in capsulated treatments than in uncapsulated treatments during storage. In sensory aspect, the yogurt sample added with uncapsulated iron and vit C, regardless of capsulation, showed a significantly high score of astringency, compared with those of control and other groups. A significantly strong sourness was observed in treatment containing capsulated iron and uncapsulated vitamin C at every time interval. The present study provides evidence that microencapsulation of iron with PGMS is effective for iron fortification in drink yogurt.

• Archives of Pharmacal Research
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• v.26 no.5
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• pp.426-431
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• 2003

This study was carried out to investigate the addition of water-soluble isoflavone into milk by means of microencapsulation technique. The yield of microencapsulation, sensory attributes, and capsule stability of water-soluble isoflavone microcapsules in milk were measured. Coating materials used was polyglycerol monostearate (PGMS), and core material was water-soluble isoflavone. The encapsulation yield of water-soluble isoflavone with PGMS was 67.2% when the ratio of coating material to core material was 15 : 1. The rate of water-soluble isoflavone release from capsules was 18, 19, and 25% when stored at 4,20, and $30^{\circ}C$ for 12 days in milk, respectively. In sensory evaluation, beany flavor and color of microencapsuled water-soluble isoflavone added milk were significantly different from uncapsuled water-soluble isoflavone added milk, however, bitterness was not significantly different. In vitro study, micro-capsules of water-soluble isoflavone in simulated gastric fluid with the range of 3 to 6 pHs were released 3.0∼15.0%, however, the capsules in simulated intestinal fluid with pH 7 were released 95.7% for 40 min incubation time. In conclusion, this study provided that PGMS as coating materials was suitable for the microencapsulation of water-soluble isoflavone, and the capsule containing milk was almost not affected with sensory attribute.

• Communications of the Korean Institute of Information Scientists and Engineers
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• v.29 no.3
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• pp.12-19
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• 2011

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.8
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• pp.1083-1093
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• 1993

Recently, some applications require the multicast service that transmit messages to multiple destinations in computer communication network enviroment. Multicast service is to send messages to the group which consists of a number of processes. A multicast group is a collection of processes which are destinations of the transmitted messages and these processes may run on one or more hosts. Therefore, it is important to manage each member of process groups in order to provide efficient multicast services. In this paper, we design and implement group management system to support multicast services. Group Management System was designed with Process Group Management System(PGMS) and Host Group Management System(HGMS). We have implemented basic primitives of PGMS, HGMS. Also, membership tree management algorithm is designed and implemented. Membership tree provides the relation of the members of multicast groups and routing Informations.

• Resources Recycling
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• v.26 no.3
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• pp.26-31
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• 2017

LIX 63 showed a selectivity for the extraction of Pd(II) over other PGMs, such as Pt(IV), Ir(IV) and Rh(III) from 6 M HCl solution. Moreover, HCl solution has significant effect on the oxidation-reduction reaction between Ir(IV) and LIX 63. Therefore, the applicability of employing LIX 63 for the separation of the 4 PGMs was investigated from 3 M HCl solution. From 3 M HCl solution, only Pd(II) was selectively extracted by LIX 63 and its extraction percentage was higher than from 6 M HCl solution. Extraction of the Pd(II) free raffinate with TBP led to the selective extraction of Pt(IV). After oxidation of Ir(III) with $NaClO_3$ to Ir(IV), extraction of the Pt(IV) free raffinate with Aliquat 336 selectively extracted Ir(IV). For each extraction step, optimum stripping conditions were obtained. By this process, it was possible to separate the 4 PGMs by solvent extraction from 3 M HCl solution.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.4
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• pp.596-601
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• 2002

The present study was designed to examine the effect of ozone treatment in microencapsulated ${\beta}$-galactosidase on inactivation of the enzyme and sterilization of microorganism. The efficiency was the highest as 78.4% when the ratio of polyglycerol monostearate (PGMS) was 15:1. Activities of lactase remaining outside the capsule were affected by ozone treatment. With the increase of ozone concentration and duration of ozone treatment, the activity reduced significantly. In sensory aspect, with 2% microcapsule addition, no significant difference in sweetness was found compared with a market milk during 12 d storage. Above result indicated that the additional washing process of lactase was not necessary to inactivate the residual enzyme. In a subsequent study, the vegetative cells of microorganisms were completely killed with 10 ppm for 10 min treatment by ozone. The present study provides evidence that ozone treatment can be used as an inactivation and a sterilization process. In addition, these results suggest that acceptable milk products containing lactase microcapsules made by PGMS can be prepared with ozone treatment.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.8
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• pp.1205-1211
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• 2003

This study was designed to examine the effect of microencapsulated iron-fortified Cheddar cheese and L-ascorbic acid as a bioavailable helper of iron on chemical and sensory aspects. Coating material was PGMS, and ferric ammonium sulfate and Lascorbic acid were selected as core materials. The highest efficiency of microencapsulation of iron and L-ascorbic acid were 72 and 94%, respectively, with 5:1:50 ratio (w/w/v) as coating to core material to distilled water. TBA absorbance was significantly lower in microencapsulated treatments than those in uncapsulated treatments during ripening. The productions of short-chain free fatty acid and neutral volatile compound were not significantly different among treatments during ripening periods. In sensory aspects, bitterness, astrigency and sourness were higher in Cheddar cheese fortified with microencapsulated iron and uncapsulated L-ascorbic acid than others. The present study indicated that fortification of iron as well as L-ascorbic acid did not show any defect problem to Cheddar cheese, and suggested the possibility of iron fortification of Cheddar cheese.

• Applied Chemistry for Engineering
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• v.19 no.5
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• pp.574-581
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• 2008

The optimum regeneration conditions for the regeneration of three way spent catalysts (TWCs), which were taken from automobiles with different driving conditions, were investigated to evaluate the suitability as alternative catalysts for removing VOCs. The spent catalysts were washed with five different acids ($HNO_3$, $H_2SO_4$, $C_2H_2O_4$, $C_6H_8O_7$, and $H_3PO_4$) to remove contaminants and examine the optimum conditions for recovering the catalytic activity. The physicochemical properties of spent and its regenerated TWCs were evaluated by using nitrogen adsorption-desorption isotherms, XRD, and ICP. The relative atomic ratios of contaminants and platinum group metals (PGMs) of the spent TWCs were greatly dependent on the placed positions. The main contaminants formed were lubricant oil additives and metallic components. Also, the regeneration treatment increased the PGMs ratio, BET surface area, and average pore diameter of TWCs. The catalytic activity results indicated that the spent TWCs have the possibility for removing VOCs. Moreover, the employed acid treatments greatly enhanced the catalytic activity of the spent TWCs. Especially, nitric and oxalic acids provided the most improvement in the catalytic behavior. The catalytic activities of the regenerated TWCs were significantly influenced by the containing platinum ratios rather than the removal ratios of contaminants and the changes in the structural properties offered by the acid treatments.

• Resources Recycling
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• v.23 no.1
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• pp.3-16
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• 2014

Recycling of spent autocatalyst that includes the platinum group metals (PGMs), namely palladium, platinum and rhodium, is a very profitable endeavor. In order to ensure an efficient promotion of an appropriate policy-making and the technical development of the recycling process of spent autocatalyst in Korea, the generated amount, trading conditions, and recycling technology for spent autocatalyst were surveyed. The generated amount of spent autocatalyst was estimated by analyzing the domestic statistical data of registration & disuse of automobiles and the records of autocatalyst installation to new cars. The review of the recycling technology was carried out by surveying the recycling processes of 'Heesung PMTech Ltd.', which is the largest company in the recycling industry for spent autocatalyst in Korea. In addition to the above, some policy suggestions for the improvement of recycling industries for spent autocatalyst were offered.