• 한국축산식품학회:학술대회논문집
• /
• 한국축산식품학회 2005년도 정기총회 및 제35차 춘계 학술 발표대회
• /
• pp.290-296
• /
• 2005

This study was carried out to develop the efficient freeze concentration process of milk through controlling the recrystallisation phenomena of ice. Freeze-concentration was progressed with multi-stage freeze concentrator and there was artificial temperature control to induce recrystallisation phenomena. In each stage of freeze concentration process, the regular recrystallisation time was fixed as 1, 2, 4 and 8 hr to compare the solute increment, yield, brix and ice-crystal size among experimental conditions. Higher concentration as total solids was observed due to the elapse of recrystallisation time, and the maximum total solids in final products: 32.67% was obtained at the ripening time of 8 hr in two-stage process. This result was excessively high concentration comparing to the existing researches and presented the possibilities of milk freeze concentration in the dairy industry, The results of brix and ice-crystal size showed the direct correlation with the recrystallisation time that meant the increased processing time showed the increment of brix and ice-crystal size. Obtained results were numerically modelled to predict the progress of concentration in the industrial process and all of them had fairly high R2 of determination. Therefore, we regarded that these numerical models could be utilized for the development of efficient technology in industrial freeze concentration process.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2004년도 추계학술대회논문집
• /
• pp.315-318
• /
• 2004

The Advantages of hot machining are the reduction of cutting forces, tool wear, and the increase of material removal rates. In this study, a hot-machining characteristics of milling by CBN tip was exprimentely analyzed, and the influence of the surface temperature and the depth of cut on the tool life were investigated. The selection of a heating method for obtaining ideal temperature of metals in machining is important. Faulty heating methods could induce unwanted structural changes in the workpiece and increase the cost. This study uses gas flame heating. It is obtained that tungsten carbide-alloyed has a recrystallisation temperature range of $800-1000^{\circ}C$ which is the high heating temperature that might induce unwanted structural changes. If it is performed at temperatures higher than $800^{\circ}C$ in machining, the possibility of unwanted structural changes and the increased wear of tool can be shown. Consequently, in hot machining of tungsten carbide-alloy, this study has chosen $400^{\circ}C-600^{\circ}C$ because the heating temperature might be appropriate in view of the cost and workpiece considerations. The results of this study experimentally shows a new machining method for tungsten carbide-alloyed that decreases the wear rate of machining tools