A Rapid and Simple Spectrophotometric Determination of Traces of Chromium (VI) in Waste Water Samples and in Soil samples by using 2-Hydroxy, 3-Methoxy Benzaldehyde Thiosemicarbazone (HMBATSC)
A rapid and simple Spectrophotmetric method has been developed for the determination of microgram amount of Chromium (VI) in aqueous dimethyl formamide (DMF). Chromium (VI) forms a yellowish green coloured M:L complex with 2-hydroxy-3-methoxy benzaldehyde thiosemicarbazone in the acidic buffer medium (pH=6.0) at room temperature. The complex shows maximum absorption at 385nm. Beer's law is obeyed in the range 0.260 to 2.60 
Short Review on Spectral Methods for the Determination of Chromiun in Human Body Fluids and Tissues
Background : The data for the determination of chromium concentrations in biological samples are still contradictory and for some biological objects varied within orders of magnitude. They are not fully clarified the role and participation in the metabolism in healthy subjects and in various diseases and conditions. Aim : One reason for the outstanding problems in the study of the functions of the chromium in the human organism is a need for accurate, with low detection limits, and access to a biomedical laboratory methods for the analytical determination. That’s why we set the aim to make a brief review of spectral methods for determination of chromium in human body fluids and tissues. Methods, results : Analytical methods which most commonly to apply at determining the chromium in biomaterials are the atomic spectral (AS) - Flame atomic absorption spectroscopy, Electrothermal atomic absorption spectrometry, Inductively coupled plasma optical emission spectrometry and Inductively coupled plasma mass spectrometry. They are accurate and have lower limits of detection, but not all biomedical laboratories have them. Of the molecular spectral, applicable methods with spectrophotometric indication for determination of chromium in biomaterials are the methods which used suitable chelating agents of chromium in micellar medium. They have limits of detection, comparable to AS-methods and are available to all biomedical laboratories. Conclusions : The lag in specifying the chromium concentrations in human bio-samples, related with clarifying the role of chromium in health and disease, can be overcome using both atomic spectral and spectrophotometric methods. Any study relating to the determination of chromium in human body fluids and tissues will contribute to the analytic of chromium and related the determining his biomedical research.
CFD simulation of hydrodynamics and heat transfer in gas phase ethylene polymerization reactors
Abstract The hydrodynamics and temperature of a two-dimensional gas–solid fluidized bed of gas phase olefin polymerization reactor had been studied. A two-fluid Eularian Computational Fluid Dynamics (CFD) model with closure relationships according to the kinetic theory of granular flow has been applied in order to simulate the gas–solid flow. Fluidization regime and gas–solid flow pattern were investigated using three different drag models. Model predictions of bed pressure drop were compared with corresponding experimental data reported in the literature to validate the model. The predicted values were in reasonable agreement with the experimental data. The temperature behavior of fluidized bed with various drag models was investigated. The temperature gradient in the primary section of the bed was much larger than the gradient in other sections and the effect of all drag models on temperature gradient along the bed was approximately similar.