• Journal of Pharmaceutical Investigation
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• v.25 no.1
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• pp.19-29
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• 1995

The study was carried out to develop useful formulation for omeprazole(OMP) through OMP-ethylendiamine complex(OMPED), and the pharmaceutical properties of formula were tested to find out the difference in vivo behaviors of formulations between the free and complexed OMP. Oral and suppository dosage forms were also formulated and the dissolution profiles and pharmacokinetic parameters were measured to observe the difference in bioavailability between the free and complex form, and the correlation between dissolution rate and bioavailability was evaluated. The results are summarized as follows; In the case of formulation for oral administration, the release of OMP from enteric OMPED pellets was found satisfactory to the requirement standard and no decomposition of OMP in the pellets was found in acidic solution. Therefore the enteric OMPED pellets are anticipated to be a stable formulation. The release of OMP from OMPED tablet with chitosan as excipient and coated with cellulose acetate phthalate was found to be significantly retarded. The results of bioavailability test for OMP and OMPED tablets with lactose-excipient showed that the AUC value of OMP tablet was $116.89\;{\mu}g\;{\cdot}\;min/ml$, that of OMPED tablet was $161.10\;{\mu}g\;{\cdot}\;min/ml$, respectively. The reason why was thought that OMP decomposes more readily in body than OMPED, and the AUC of the tablet with chitosan-excipient and coated with cellulose acetate phthalate was most enhanced. In the case of bioavailability for suppositories with OMP, $OMP-{\beta}\;-cyclodextrin$ complex and OMPED, the AUC of OMPED suppository was most increased. From the above results, it is thought that the more stable and bioavailable oral or rectal dosage forms could be developed by using the OMPED as a potential OMP complex.

• Polymer(Korea)
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• v.35 no.1
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• pp.17-22
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• 2011

Polypropylene/multi-walled carbon nanotube(PP/MWCNT) composites along with various MWCNT contents up to 20 wt% were prepared by a twin screw extruder. Nanocomposites having 20 wt% MWCNT as a master batch(M/B) were diluted with PP by way of melt compounding. The electrical/thermal conductivity, morphology, thermal/viscoelastic/mechanical properties were investigated with the variation of MWCNT contents. Also, we compared some properties between 1-step PP/MWCNT and the diluted PP/MWCNT composites. The percolation threshold of electrical and thermal conductivity was measured at about 3 wt% MWCNT. And conductivity of diluted PP/MWCNT composites were superior to those of PP/MWCNT composites. The non-isothermal crystallization temperature and thermal decomposition temperature appeared at higher temperatures with increasing MWCNT contents. Morphology showed that length of MWCNT in diluted PP/MWCNT composites was shortened by twice melt blending, which contributed to improve the tensile strength of PP/MWCNT composites.

• Journal of Aquaculture
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• v.17 no.2
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• pp.144-150
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• 2004

This experiment was conducted to evaluate the parameters such as nutrient requirements, POY, AnV, Totox, VBN, total plate count, dietary fatty acids and amino acids composition, that are not included in the registered standard composition items required by the Ministry of Agriculture and Forestry, of a moist pellet (MP), three domestic extruded pellets (DEP-1, DEP-2, DEP-3), and two foreign extruded pellets (FEP-1, FEP-2) that are utilized by domestic flounder farms at present. The crude protein was added in excess of the dietary protein requirement in 6 kinds of feeds. When considering the proper PH ratio, it is obvious that protein was added in excess, especially in MP and FEP-2. Crude fat was also added in excess, especially in FEP-1. MP contained a higher dietary phosphorus content than formulated feeds, surpassing the dietary phosphorus requirement and greatly increasing the possibility for causing water pollution. The oxidation of fatty acid and decomposition of protein in MP were higher than in formulated feeds, and may also cause problems on fish farms. Also, it is difficult to store and manage MP, Among the fatty acids, EPA and DHA contents in MP were higher than those in formulated feeds. It is necessary to conduct further studies of EPA and DHA contents in formulated feeds. Lysine content in MP and FEP-2 could meet the dietary lysine requirement of flounder, however, the possibility of insufficient lysine content in the other formulated feeds was high and we considered that extra supplementation was necessary. Therefore, it is necessary to set up quality control standards according to fish species and sizes while considering the specific character of aquatic formulated feeds to restore the confidence of feed companies and aquaculturists to these feeds. This may be an opportunity to make an earlier change from MP to formulated feeds.

• Journal of Korean Society of Forest Science
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• v.98 no.4
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• pp.426-434
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• 2009

This study was carried out to derive the most optimal production process for the wood fuels(chip and pellet), by collecting cost data on each procedure through the life cycle assessment approach, and to compare between the profitability and efficiency, from the view points of producers and consumers, irrespectively. The costs accounted in this analysis were based on the opportunity cost. The results show that wood chips are cheaper than wood pellets in production costs. In respect to the process with the lowest production cost, while wood chips should be to crush collected residues into pieces on the spot for merchandizing, wood pellets need to be transported to manufactory for pelletizing. The study findings also include that the profits, which is estimated by subtracting expenses from gained sale revenue, were a bit higher for wood chips than wood pellets. Additionally, the price ratio of wood pellets to wood chips for getting the same caloric value appears to be 1.27. Despite of economic benefits of processing wood chips, there are several problems in practice. For producers, there is a possible increase in not only transportation cost for conveying crushers to the dispersed places, but storage cost due to the lack of the marketplaces in the immediate surroundings. For consumers, on the other hand, there are some challenging issues, such as bulky storage facility requirement, additional labor for fuel supplement, frequent ashes disposal, and decomposition in summer and freezing in winter caused by wood chips' own moisture.

• Clean Technology
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• v.30 no.2
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• pp.134-144
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• 2024

In this study, the mechanical stability of red mud was improved for its commercial use as a catalyst to effectively decompose HFC-134a, one of the seven major greenhouse gases. Red mud is an industrial waste discharged from aluminum production, but it can be used for the decomposition of HFC-134a. Red mud can be manufactured into a catalyst via the crushing-preparative-compression molding-firing process, and it is possible to improve the catalyst performance and secure mechanical stability through calcination. In order to determine the optimal heat treatment conditions, pellet-shaped compressed red mud samples were calcined at 300, 600, 800 ℃ using a muffle furnace for 5 hours. The mechanical stability was confirmed by the weight loss rate before and after ultra-sonication after the catalyst was immersed in distilled water. The catalyst calcined at 800 ℃ (RM 800) was found to have the best mechanical stability as well as the most catalytic activity. The catalyst performance and durability tests that were performed for 100 hours using the RM 800 catalyst showed thatmore than 99% of 1 mol% HFC-134a was degraded at 650 ℃, and no degradation in catalytic activity was observed. XRD analysis showed tri-calcium aluminate and gehlenite crystalline phases, which enhance mechanical strength and catalytic activity due to the interaction of Ca, Si, and Al after heat treatment at 800 ℃. SEM/EDS analysis of the durability tested catalysts showed no losses in active substances or shape changes due to HFC-134a abasement. Through this research, it is expected that red mud can be commercialized as a catalyst for waste refrigerant treatment due to its high economic feasibility, high decomposition efficiency and mechanical stability.