Investigation of Breakthrough Curves of Citric Acid Adsorption

In this paper, experimental breakthrough curves for citric acid adsorption from aqueous solution onto ion-exchange resin at 20, 35, 55 °C have been obtained by some weak and strong basic anionic resins, such as IRA-92, IRA-93, IRA-420 and IRA-458. The results show that amberlite IRA-93 has good performance and is one of the best resins in the process of citric acid recovery from aqueous solution. Also, the temperature effect study shows that an increase in temperature causes an increase in diffusion coefficient of particles, but the saturation capacity of resin decreases. To achieve an appropriate model, three mathematical models were analyzed to predict system properties based on statistical tests, and finally, the appropriate model was determined. To examine model capability, mathematical equations have been implemented in various breakthrough curve data obtained by other investigators, and the results show appropriate conformity

Workpiece surface flatness improvement by tool length compensation in micromilling

Micromilling quality improvement requires an accurate management of all the involved resources (machine tool, tool, fixture, workpiece). Specific attention has to be paid, comparing to macro operations, also to machining strategies and tool and workpiece measuring strategies. The extreme workpiece accuracy requires to reinterpret some procedures, already applied in the macro world, with the purpose to minimize errors. It is the case of the tool length compensation, which plays a strong role on the micromilling overall performance. In order to demonstrate the importance of factors affecting tool length, as machine spindle thermal transients and tool wear assessment, the present paper takes the workpiece flatness deviation as a case study and presents a manufacturing and measuring strategy able to meet a challenging flatness constraint