Abdulaziz Alghamdi

Natural convection and entropy generation in a cubical cavity with twin adiabatic blocks filled by aluminum oxide–water nanofluid

ABSTRACT A finite volume-based three-dimensional numerical simulation on natural convection and entropy generation in a cubical cavity filled with a nanofluid of aluminum oxide–water is presented by vorticity–vector potential formalism. The blocks are adiabatic and the vertical walls are differentially heated unidirectionally. The variables considered are Ra, volumetric fraction of aluminum oxide particles, and block size. The results for fluid flow with a single-phase model are elucidated with iso-surfaces of temperature, Nusselt number, and Bejan number. The local entropy generated was due to friction surges when the volumetric fraction of nanoparticles was increased. The average Nusselt number rose with the increase in Ra and volumetric fraction of solid particles and declined with the increase in block size.

Natural convection and entropy generation in a three dimensional volumetrically heated and partially divided cavity

Purpose The purpose of this paper is to provide a solution for natural convection in a cavity with a partial heater in case of volumetric heating and analysis of the entropy generation. Design/methodology/approach The control volume method based on three-dimensional (3D) vorticity-potential vector was applied to solve governing equations of natural convection in a 3D cavity with a fin for different governing parameters as external Rayleigh numbers (103=RaE=106), internal Rayleigh numbers 103=RaI=106, partition height (0.25=h=0.75) and partition location (0.25=c=0.75). A code was written by using Fortran platform. Findings The edge of the fin becomes important on entropy generation. The ratio of the RaI/RaE plays the important role on natural convection and entropy generation. The variation of external Rayleigh number becomes insignificant for the RaI/RaE>1. Originality/value The originality of this work is to analyze the entropy generation and natural convection in a cubical cavity with volumetrically heating.

Conventional, Enhanced, and Alkaline Coagulation for Hard Ghrib Dam (Algeria) Water

This work aims to study coagulation process for hard Ghrib Dam (GD) water treatment. Conventional coagulation (CC), enhanced coagulation (EC) and alkaline coagulation (AC) experiments were realized on jar tests. This study demonstrated the effectiveness of GD water treatment by the EC process compared to CC. Indeed, by CC, it has been demonstrated that each of the two coagulants studied (alum and FeCl 3 ) is effective for remarkable reductions in OM of 36% and 47.4%, respectively. However, EC, by slightly acidifying water, gave better removal efficiencies of the studied parameters. Indeed, the best abatement of OM is about 78% when water is treated with ferric chloride at pH 5.5, lowered with nitric acid. The observed disadvantage here is the residual nitrate, which existed in the raw water at only low level. On the other hand, at the same pH, the reduction of the OM is 64% when alum is used as coagulant. In addition, the data collected have led to the conclusion that the physicochemical quality of the GD water has a high salinity and lowering its pH (EC) does not affect it at all. On the other hand, its pH elevation (AC) considerably reduces its total hardness which is 41% with NaOH. Such a performance advantageously positions this total hardness reduction technology among the possible solutions to the problems associated with total hardness.

Decolorization of Methyl Orange (MO) by Electrocoagulation (EC) Using Iron Electrodes Under a Magnetic Field (MF). II. Effect of Connection Mode

This work aims to investigate the electrocoagulation (EC) of methyl orange (MO) using iron electrodes and examine the effect of magnetic field (MF) on EC performance focusing on electrodes connection mode. Experimentally, an electrochemical cell is made in a configuration as simple as possible to impose a MF parallel to the current density and to allow an evaluation of the performance of the EC coupled to the MF. After 12 min of treatment, at pH 7.25, and with a current density of 64 A/m2, the MO decolorization obtained by EC-MF reaches 95%; this rate is higher than that obtained by the EC alone, which does not exceed 70%. In the MF presence and under optimal conditions, the decolorization increases allowing a gain in energy consumption (36%) from 30 to 19 kWh/kg dye. The decolorization with the bipolar system in series (BP-S) reaches 98% while it reaches 64% and 74% for the mono-polar in series (MP-S) and the mono-polar in parallel (MP-P), respectively. Consequently, the BP-S is more efficient.

Decolorization of BF Cibacete Blue (CB) and Red Solophenyle 3BL (RS) Using Aluminum Sulfate and Ferric Chloride

Coagulation process is largely applied for dye removal from textile wastewater treatment. This research aims to focus on implied mechanisms through coagulation of such wastewater. In this work, jar tests are performed to assess the coagulation process as a technique to treat synthetic solutions containing two textile dyes: BF cibacete blue (CB) and red solophenyle 3BL (RS). The effects of operational parameters such as coagulant type (FeCl3 and Al2 (SO4)3. 18H2O (alum)) and dose, initial pH, and dye concentration are studied. For a fixed 15 mg/L concentration of the two dyes, the FeCl3 optimal doses are found to 80 and 20 mg/L for RS and CB with removal rates of 65 and 89%, respectively. Regarding alum, discoloration is achieved at 44 and 77% for CB and RS with optimal doses of 80 and 40 mg/L, respectively. Similar efficiency trends are also obtained for a 50 mg/L concentration of the two dyes. The involved coagulation mechanisms are: charge neutralization followed by precipitation of the insoluble dye-coagulant complexes, and their adsorption into the Al or Fe hydroxides. It would be interesting to follow a real effluent application on the textile industry possibly containing the two dyes tested in this work.

Decolorizing Methyl Orange by Fe-Electrocoagulation Process – A Mechanistic Insight

The aim of this work is to study the removal of methyl orange (MO) using electrocoagulation (EC) process. An electrochemical cell consisting of two iron electrodes, with 22.5 cm 2 as an active surface, is used. Operating conditions are optimized such as nature and concentration of the supporting electrolyte, current density, pH, inter-electrode distance, MO concentration, and the connection mode. The decolorization degree obtained after 15 min of EC reached 83% at pH 7.25 with a current density of 64 A/m 2 . Depending on pH, three EC process mechanisms are suggested and less or more significant removal performances are obtained in these tests. The Scanning Electron Microscopy (SEM) observations show that the flocs formed by the EC process have two distinct morphologies: a lumpy structure and an amorphous structure, formed by particles of various sizes. The Energy Disperses X-ray (EDX) analysis of the surface of the flocs formed by the EC process shows a spectrum with levels of major elements of iron, oxygen and chloride, as well as carbon, sodium and aluminum are detected as minor elements. As proved in terms of MO elimination through this research and due to its several advantageous, EC process would find its convenient place in wastewater treatment technology.

Fostering Students’ Creativity Through Innovative Learning Tools

For the last two decades, creativity continued to occupy a prominent position in public as well as academic discourses in many parts of the world. As creativity depends on knowledge, curiosity, imagination, and evaluation, so focusing on these four pillars in education will increase its development. Fostering students’ creativity and innovation capabilities has always been at the heart of universities’ endeavor and engagement. The aim of this study is to illustrate the links between innovating learning tools and students’ creativity. Media-reinforced cooperative studying domains may assist foster creative and critical thinking in net-generation business students; there are obstacles to the acceptation of these instruments both from the viewpoint of teachers and students. Regardless of these rejections, most students liked the non-linear, multi-media feature of the innovative learning domain and wanted more such actions to be advanced hereafter.

Big Data: Myths, Realities and Perspectives - A Remote Look

In a world where data is gathered in ever‐increasing quantities, summing more of what persons and organizations perform, and catching smallest detail of their comportment. There are three fashions to distinguish data occasionally reported as volume, variety, and velocity—the meaning of Big Data. This review aims to focus on defining Big Data and describing some of its myths and realities. The significance of big data does not focus on how much data is possessed, but what things may be performed with it. Data may be extracted from any origin and examined to detect replies that let 1) cost decreases, 2) time decreases, 3) fresh product expansion and studied offerings, and 4) smart decision making. As a magic, charming, and mysterious noun, Big Data remains an attractive novel field in both science and technology. Despite of the developed technology and open knowledge, Big Data still needs more familiarization and demystification. More developed computer skills will be needed to understand and touch its practical extent.