Prediction of Slip Velocity in Rotating Disc Contactors

A generalized correlation for slip velocity in terms of fundamental variables (specifically excluding dispersed phase hold-up), using a large bank of published data along with those of the author is presented. A collection of 1412 experimental measurements (for 12 liquid–liquid systems from 13 different sources) representing slip velocity data over a wide range of variables is used for developing a new empirical correlation. The proposed correlations are more exact and simpler to use than the earlier correlations. In this present work, two regions of operations are also confirmed. © 1997 SCI.     

The chlor-alkali process: Work in Progress

The chlor-alkali process has come a long way from the days of the diaphragm and mercury cell process to the present membrane cell process, with huge reduction in power consumption and hence its carbon footprint. Although there is reduction in the release of highly toxic mercury to the environment, there is increased release of less harmful substances such as chloride and chlorate because the membrane cell is less tolerant to contaminants, and hence requires higher purity brine. The technology providers have continued to improve upon the process to reduce power consumption and to reduce the plant’s footprint. This review looks briefly at the three technologies and attempts to look at where we currently are at. All new chlor-alkali plants being built are of the membrane process. This review mentions some of the areas where improvements can be made to the membrane process.     

Review on mobility aware MAC protocol using Mobile internet of things

Multimedia Tools and Applications - Modern boom and understanding of our growing needs, applications based on the Mobile Internet of Things (MIoT) are becoming important for future internet...     

Halogen-free acylation of toluene over FeSBA-1 molecular sieves

Three-dimensional cage type iron substituted mesoporous silica with different iron contents (FeSBA-1) was synthesized in a highly acidic media using cetyltriethylammonium bromide and tetraethylorthosilicate as a template and a silica source, respectively. Acylation of toluene with acetic anhydride (AA) was carried out over FeSBA-1 mesoporous catalysts with different n_Si/n_Fe ratios in the temperature range 80–180 °C for a time-on-stream of 1–6 h under liquid phase conditions. The important factors affecting the conversion and the selectivity of the reaction, such as the reaction temperature, feed ratio, catalyst weight and time-on-stream were studied and the results are discussed in detail. The reaction conditions were optimized and the n_AA/n_Toluene ratio of 2 and catalyst weight of 0.1 g (3.3 wt% of total reaction mixture) were maintained for all catalytic runs. It was found that the catalytic activity is strongly influenced by the amount of tetrahedral iron in the catalysts. Among the catalysts used in the present study, FeSBA-1(36) showed a high toluene conversion and selectivity to p-methylacetophenone (p-MAP) under the optimized reaction conditions. It was also found that the selectivity for p-MAP was always higher than m-MAP and o-MAP for all the catalysts and the activity of the catalysts changes in the following order: FeSBA-1(36) > FeSBA-1(90) > FeSBA-1(120).     

A 52?pJ/bit 433-MHz low power OOK transmitter

An OOK transmitter in 433-MHz ISM band employing a speed-up circuit is described. The proposed speed-up circuit accelerates the start-up of the oscillator and buffer by briefly increasing the bias currents during transmission of bit “1”. This leads to a data rate increase from 3 to 10-Mb/s without any penalty on power consumption. The data rate can also be made adaptable by varying the duration in which the bias current is increased. The proposed OOK transmitter is implemented in 0.35-μm CMOS technology. The measured results show that the transmitter achieves a maximum data rate of 10-Mb/s with a dc power consumption of 518 μW from a 1-V power supply, yielding an energy efficiency of 52 pJ/bit or 0.97 nJ/bit/mW when normalized to the output power. This paper also derives a closed form equation which describes the transient behavior of Colpitts oscillator during start up.     

Removal of phenol from aqueous solution and resin manufacturing industry wastewater using an agricultural waste: rubber seed coat.

Activated carbon prepared from rubber seed coat (RSCC), an agricultural waste by-product, has been used for the adsorption of phenol from aqueous solution. In this work, adsorption of phenol on rubber seed coat activated carbon has been studied by using batch and column studies. The equilibrium adsorption level was determined to be a function of the solution pH, adsorbent dosage and contact time. The equilibrium adsorption capacity of rubber seed coat activated carbon for phenol removal was obtained by using linear Freundlich isotherm. The adsorption of phenol on rubber seed coat activated carbon follows first order reversible kinetics. The suitability of RSCC for treating phenol based resin manufacturing industry wastewater was also tested. A comparative study with a commercial activated carbon (CAC) showed that RSCC is 2.25 times more efficient compared to CAC based on column adsorption study for phenolic wastewater treatment.     

Numerical study of heat and moisture transport through concrete at elevated temperatures

This research article focuses on numerical investigation of heat and moisture transport through concrete exposed to high temperatures such as fire. The conservation equations for moisture and energy transport through concrete have been represented in terms of temperature, pore pressure and vapor content as field variables. As the resulting governing equations are coupled and non-linear, the equations were solved numerically using Galerkin’s weighted residual finite element method and an iterative solution technique. After validating the model, a detailed simulation study has been carried out to understand the role of gradients of temperature, pore pressure and vapor content on heat and moisture transport through concrete exposed to ISO 834 fire curve. Results obtained at the end of 30 minutes exposure of concrete show that the temperature gradients become very steep after 12 minutes of exposure of concrete, which in turn results in increased vapor generation and 93% of vapor generation is completed at the end of 20 minutes. Due to steep temperature gradient along the length of concrete, condensation of vapor takes place which is followed by blockage of pores giving rise to sudden peak pore pressure rise and 97% of peak pore pressure is attained at the end of 18 minutes itself. It is observed that for the initial 18 minutes, the peak pore pressure front and peak vapor content front follow the same path and after 18 minutes the peak vapor content front moves slightly ahead of the peak pore pressure front.     

Experimental study on productivity enhancement of an improvised inclined solar still

Experimental studies are carried out on the inclined solar still with baffle plates for enhancing its performance. The baffles placed in the inclined solar still act as a solar collector which helps in increasing the contact time with solar radiation thereby raising the saline water temperature. Experiments are carried out during winter and early summer climate of Chennai, India. Experimental parameters, such as ambient temperature, solar radiation, glass temperature, water temperature and distillate output are recorded. Hourly productivity is found to be higher during sunny days. The estimated production of fresh water through analytical study is 3.50?kg/m² per day for a minimum mass flow rate of 0.0833?kg/min. The actual experimental yield is 2.793?kg/m² per day. Also, the inlet saline water temperature affects the yield and the latter is found to be highest at 48.5°C.     

Studies on geotechnical properties of Prosopis juliflora ash treated black cotton soil

Bulletin of Engineering Geology and the Environment - The pavements of the Beijing Capital International Airport (BCIA), China, where a buried fault zone lies beneath, have undergone continuous...