The effect of electrolysis operating parameters on the removal efficiency of cadmium from a simulated wastewater was studied by adopting response surface methodology combined with Box–Behnken Design. As a new electrode design, spiral-wound woven wire mesh rotating cylinder electrode was used for cadmium removal. Current (240–400 mA), rotation speed (200–1000 rpm), initial cadmium concentration (200–600ppm), and cathode mesh number (30–60) were chosen as independent variables while the removal efficiency of cadmium was considered as a response function. The results revealed that the rotation speed has the major effect on the removal efficiency of cadmium. Regression analysis showed good fit of the experimental data to the second-order polynomial model with a coefficient of determination (R2) value of 0.9931 and Fisher F-value of 89.82. The optimal conditions within the experimental ranges of the independent variables were a current of 345 mA, a rotation speed of 800 rpm, an initial cadmium concentration of 500 ppm, and a mesh number of 30, where concentration of cadmium was diminished from 500 to 8 ppm after 60 min of electrolysis with a specific energy consumption of 3.12 kWh kg−1 and a current efficiency of 41%.
The present work investigates the effect of magneto – hydrodynamic (MHD) laminar natural convection flow on a vertical cylinder in presence of heat generation and radiation. The governing equations which used are Continuity, Momentum and Energy equations. These equations are transformed to dimensionless equations using Vorticity-Stream Function method and the resulting nonlinear system
of partial differential equations are then solved numerically using finite difference approximation. A thermal boundary condition of a constant wall temperature is considered. A computer program (Fortran 90) was built to calculate the rate of heat transfer in terms of local Nusselt number, total mean Nusselt number, velocity distribution as well as te
This study reveals the results of a numerical simulation performed using the ABAQUS/CAE finite element program. The study aimed to provide a simulation model that can forecast the shear behavior of reinforced concrete beams confined with reinforcing meshes. Limited numerical studies have been conducted using geogrid or FRP mesh as shear reinforcement, with limited representation accuracy and limited material quality. The results were compared to published experimental findings in the literature. The finding of the finite element model and the experimental results were highly comparable; consequently, the model was determined to be valid. Following this, the domain of numerical analyses was broadened to include the investigation of m
... Show MoreThis paper aims to study the biosorption for removal of lead, cadmium, copper and arsenic ions using algae as a biosorbent. A series of experiments were carried out to obtain the breakthrough data in a fluidized bed reactor. The minimum fluidization velocities of beds were found to be 2.27 and 3.64 mm/s for mish sizes of 0.4-0.6 and 0.6-1 mm diameters, respectively. An ideal plug flow model has been adopted to characterize the fluidized bed reactor. This model has been solved numerically using MATLAB version 6.5. The results showed a well fitting with the experimental data. Different operating conditions were varied: static bed height, superficial velocity and particle diameter. The breakthrough curves were plotted for each metal. Pb2+ s
... Show MoreContamination of surface and groundwater with excessive concentrations of fluoride is of significant health hazard. Adsorption of fluoride onto waste materials of no economic value could be a potential approach for the treatment of fluoride-bearing water. This experimental and modeling study was devoted to investigate for the first the fluoride removal using unmodified waste granular brick (WGB) in a fixed bed running in continuous mode. Characterization of WGB was carried out by FT-IR, SEM, and EDX analysis. The batch mode experiments showed that they were affected by several parameters including contact time, initial pH, and sorbent dosage. The best values of these parameters that provided maximum removal percent (82%) with the in
... Show MoreThis investigation was carried out to study the treatment and recycling of wastewater in the cotton textile industry for an effluent containing three dyes: direct blue, sulphur black and vat yellow. The reuse of such effluent can only be made possible by appropriate treatment method such as chemical coagulation. Ferrous and ferric sulphate with and without calcium hydroxide were employed in this study as the chemical coagulants.
The results showed that the percentage removal of direct blue ranged between 91.4 and 94 , for sulphur black ranged between 98.7 and 99.5 while for vat yellow it was between 97 and 99.
To investigate the efficacy of polyether‐ether‐ketone (PEEK) wire as a fixed orthodontic retainer, by comparing its performance to other retainer wires and optimizing its adhesion to composite bonding materials.
Retainer wires of 15 mm segments were used, PEEK wires were prepared in cylindrical form with 0.8 mm diameter, and had two surface treatments namely air‐abrasion and conditioning with adhesive system. Three different metallic retainer wires were used for comparison and three tests were performed; two tests measured debonding force and associated wire deflec
في هذا العمل تم دراسة المقاسات الاولية من النمطEn المرصوصة المكتضة ودراسة تعيم هذا المفهوم الى مفهوم الآثار الاولية من النمط En المرصوصة المكتضة حيث تم دراسة بعض العلاقات والتشخيصات الخاصة بهذه المفاهيم حيت تم برهنت العلاقات الخاصة بمفهوم المقاسات الاولية من النمط En المرصوصة المكتضة ليكن ₩ مقاس و كل مقاس جزئي هو اولي من النمط En فان المقاس ₩ هو مقاس اولي من النمط En مرصوص مكتض اذا و فقظ اذا كل مقاس جزئي د
... Show MoreA lab-scale packed Bio film reactor was used for ethanol production by fermentation of sugar solution using a local
isolated yeast saccharomyces cerevisia and glutaraldelryde on gelating as a covalent bounding agent. In this study four
types of packing in the reactor were used. They are; polypropylene mesh, glass rashig rings, ceramic rashig rings and
glass beads. Glucose solutions were used as substrate with four concentrations; (5, I 0, I 5, 20 g/l). Results show that the
ethanol productivity was increase with increasing sugar concentration. Also it was found that polypropylene mesh
packing give the highest productivity while glass beads gives the lowest productivity. The experiments were conducted at
three temperatur
