UTILIZATION OF POPULATION BALANCES IN SIMULATION OF LIQUID-LIQUID SYSTEMS IN MIXED TANKS

A simulation model has been developed to model drop populations in a mixed tank. A multiblock mixed tank model has been used with the drop population balance equations developed in the literature. The drop breakage and coalescence functions used in the population balance model take into account the local turbulent energy dissipation values. The drop breakage and coalescence function parameters are fitted against drop size measurements from dense liquid-liquid dispersions, which were assumed fully turbulent. Since the local turbulence and flow values of a mixed tank are used in the present model, the fundamental breakage and coalescence phenomena can be taken into closer examination. Furthermore, the present model is capable of predicting inhomogeneities occurring in a mixed tank. It is also considered as an improved tool for process scale-up, compared to the simple vessel-averaged population balance approach, or use of correlations of dimensionless numbers only. The present model can use two sources of data for fitting parameters in the drop rate functions. One is the transient data of the measured drop size distribution as the impeller speed is changed. The other is the time-averaged data measured at different locations of the mixed tank. Different flow regions can be chosen from direct measurements or from the CFD simulations in a straightforward manner. CFD flow simulation results can be used when no experimentally obtained flow conditions are available. This is especially useful for nonstandard vessels, such as reactors containing cooling coils.     

Forecasting the unresponsiveness to verbal command on the basis of EEG frequency progression during anesthetic induction with propofol

The objective of this study is to model the association between the electroencephalogram (EEG) spectral features and the novel r scale representing the sedative effects of the propofol anesthetic drug. On the basis of the r scale, the unresponsiveness to the verbal command (LVC) is forecasted. EEG recordings are taken from a 16-patient study population undergoing propofol anesthetic induction. EEG was filtered into consecutive 4-Hz passbands up to 28 Hz. Of these time-series, the amplitude envelopes were extracted and used as input features to the first and the second-order polynomial multiple linear regression models. The values r epsilon [0.4, 1] were predicted with the R2 value of 0.775 with a cross validation. The LVC times were forecasted with the median error of 5%-7% or equivalently 10-13 s. In contrast, using the median of the measured LVC times of the training population as a forecast, the corresponding error was 12% or 26 s. The results suggest an acceptable correlation between the r scale and the EEG spectrum in the studied range. Moreover, the r values of an individual can be predicted using a population model. The suggested framework enables forecasting the LVC, which may open new possibilities for steering the drug administration.     

系统内可编程时钟提高设计灵活性和便携性

先进电子系统的功能与特性的整合在持续快速发展,这导致了目前时钟网络设计中的许多主要障碍。为满足各种芯片和接口在频率、I/O和性能方面对时钟的需求,经常需要既没有灵活性,也不具备便携性的非常精确的执行。最终的结果往往是一个由多个分散的振荡器和缓冲器组成的支离破碎的解决方案,只要系统要求不改变,它就可以工作。这种方法会使物料成本(BOM)、库存管理和设计资源的成本居高不下。进入新的多PLL时代,可编程时钟通过采用I2C和JTAG这样的行业标准接口,加上非易失性存储器就可以达到解决这些挑战的目标。通过通用接口实现系统内…     

Influence of internal phase properties on zeta-potential and dielectric constant of o/w emulsion

Dielectric constant (DEC) of internal phase influenced the zeta potential (ZP) of o/w emulsion prepared with or without emulgent. In both systems ZP and DEC of internal phase exhibited an approximately linear relationship. Using homologous aliphatic hydrocarbons as internal phases, emulsions were prepared with polysorbate-80. Increase in carbon chain length brought about increase in interracial area and decrease in ZPs of emulsions. A fair inverse correlation between ZP and DEC of internal phase was revealed in this series. Increase in phase volume ratio from 0.05 to 0.3 brought about limited changes in ZPs whereas by further increasing phase volume ratio, ZP decreased steadily. Studies pertaining to the effect of phase volume ratio on DEC of o/w emulsions are in accordance with earlier observations. Increase in phase volume ratio causes a steady decrease in DEC of emulsion. Of the five equations employed, the Bruggeman equation appears to predict the observed values more accurately.     

A PC Program for Preliminary Design of a Continuous Well-Mixed Fluid Bed Dryer

This communication gives an outline of a user-friendly PC wde developed for preliminary design of a fluid bed dryer (FBD) and its essential ancillaies e.g. cyclone, fan etc.. The fluid bed dryer may have internal heat exchangers. Correlations used for design calculations are presented. The program permits estimation of the energy consumption as well as the installed and operating costs.