Algerian Journal of Engineering and Technology (AJET)
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Effect of gamma radiation on the antibacterial activity of Syzygium aromaticum
Get PDFIrradiation is known as an effective method for decontamination and preservation of chemical and nutritional properties of various medicinal herbs and spices. This study was undertaken to evaluate the influence of irradiation dose (10kGy) on the antibacterial potency of Syzygium aromaticum (clove), plant known for its various biological properties notably its powerful antimicrobial power. Syzygium aromaticum (S. aromaticum) extract, prepared by maceration in methanol, was characterized by phytochemical analysis and colorimetric determination of chemical compounds. The antibacterial potential was also evaluated against this extract by observing growth inhibition zones. The result of gamma radiation effect on the clove, showed the preservation of main chemical constituents, with a significant increase in the content of total polyphenols and flavonoids. The methanolic extract of S. aromaticum revealed an inhibitory effect on the resistant strains, which improved significantly under the gamma radiation effect. These results seem very encouraging and suggest using gamma radiation as procedure to decontaminate the medicinal herbs and spices and improve the composition of extracts in bioactive molecules as well as their biological activities
Phase formation and structure in rapidly quenched Ni50Al50 alloy
Get PDFA novel synthesis process combining arc melting and rapid quenched system has been developed to manufacture Ni50Al50 alloy which is not easy to form using conventional fabrication approaches. In this work, Nickel-Aluminum alloys with nominal composition Ni50at%Al50at% were prepared by melting pure nickel pieces (99.97%) and pure Al pieces (99.999%) under the protection of argon atmosphere using induction furnace followed by experiments performed by a new in-situ solidification method with arc melting. Alloy so produced is characterized by a compact structure with a minimum porosity. X-ray phase analysis revealed the existence of a one-phase structure of the rapidly quenched Ni50Al50 alloy. In this study, rapid quenching in liquid nitrogen from a high-temperature (1638 °C) state resulted in a non-uniform grain size distribution for Ni50Al50 alloy. Some grains were as small as 20 nm, while larger grains reached about 100 nm, with an average diameter of 74.8 nm. In contrast, cast ingots made with an induction furnace had larger average grain sizes (160-600 nm). These findings demonstrate the potential to create nanocrystalline structures in the Ni50Al50 alloy through rapid solidification in liquid nitrogen, offering the possibility of milling the synthesized alloy into nano-powders for composite matrix use during sintering. The nano-structuration behaviors and microstructures for Ni50Al50 alloy synthesis and powders nanoparticles obtained by milling have been investigated with the aids of Optical Microscopy (OM), X- Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM).The results show that the samples rapidly quenched in liquid nitrogen from high temperature as solidus state with temperature slightly lower than 1638°C, restrain the precipitation of NiAl phase as clusters, consequently, the NiAl specimens above solidus follow by rapidly quenched in liquid nitrogen among NiAl nanoparticles make the phase distributes homogeneously
Motor speed control using a fault tolerance implementation on SRAM-based FPGA
Get PDFDC motor speed control is a critical task in many applications, such as industrial automation, aerospace and robotics. To ensure reliable and robust performance, a fault tolerance implementation is necessary. In this paper, we present a DC motor speed control system using an SRAM-based Field-Programmable Gate Array (FPGA) with a fault tolerance implementation. The control system utilizes a Pulse Width Modulation (PWM) and Proportional Integral Derivative (PID) to regulate the voltage applied to the motor. To ensure the reliability of the system, a MicroBlaze Triple Modular Redundancy is implemented, in which multiple controllers control the motor in parallel and their outputs are compared. The results show that the implementation significantly improves the reliability and robustness of the DC motor speed control system
The Adsorptive properties of 4-Hexyl-tertrahydro-thiopyran-1,1-diode on Al(110) and Fe(111) surface using DFT method
No full textAluminum and iron are highly significant industrial commodities that are used to make anything from tools and concrete construction to roofing sheets and other roofing-related products. Even though they generate a protective oxygen barrier that prevents corrosion, they are nevertheless susceptible to corrosion in extreme conditions. In order to achieve the stable shape of the molecule HTTD, a theoretical investigation on the corrosion inhibition of metals like Aluminum and iron was conducted utilizing local density function B3LYP under limited spin polarization DNP foundation. The values of local/global reactivity parameters, including the (ω+) electroaccepting power and (ω-) electrodonating power between the inhibitor molecule and the metal surfaces, were demonstrated. These parameters included EHOMO, ELUMO, energy gap (∆Eg), electronegativity (χ), global hardness (η), global electrophilicity index (ω), and fraction of electron transfer (∆N). Physisorption mode was defined as the mode of interaction of HTTD on Aluminium and Chemical Adsorption on Iron surface based on the simulation modeling output. The outcome of Fukui functions revealed that the focus point for the selectivity of electron donation and acceptance between the metal and the moiety is a hetero-atom present in the molecule such as oxygen, sulfur and the methylene (-CH2-) functional group
Stability of flowing PbLi alloy between coaxial cylinders under magnetic field
Get PDFIn this research, numerical simulations were performed to investigate the stability of a flowing PbLi alloy (Pr = 0.032) within two coaxial vertical cylinders, while subjected to an axial magnetic field. The primary objective of this study was to analyze how the presence of the axial magnetic field affected both vortex breakdown and swirling flow phenomena. To achieve this, the governing equations, which included the Navier-Stokes equations and potential equations, were solved using the finite-volume method. The numerical simulations presented results for three aspect ratios (A= 1.5, 2.0, and 2.5) and three annuli (R = 0.9, 0.8, and 0.7). In the hydrodynamic scenario, vortex breakdown was observed close to the inner cylinder as a result of the intensified pumping effect caused by the Ekman boundary layer. The findings demonstrated that the onset of oscillatory instability was initiated by increasing the Reynolds number to a critical value. However, when a magnetic field is intensified, the vortex breakdown vanishes, and its limits will shrink. Stability diagrams were created to depict the boundaries within which a vortex breakdown bubble emerges, allowing for a visual picture of its occurrence
A Theoretical properties of Thiazepine and its derivatives on inhibition of Aluminium Al (110) surface.
No full textIn this work, corrosion inhibition of Aluminium was evaluated theoretically through quantum functions. The studied molecules thiazepine and its derivatives were optimized and simulated with local density function B3LYP using DFT-D under restricted spin polarization DNP basis to obtain the stable geometry of the thiazepine structures. the Fukui density functions were evaluated to determine the frontier molecular orbitals (FMO) of the compounds. The number of adsorption sites (physisorption) was the mode of interaction with the heteroatoms such as Chlorine, Nitrogen, Sulphur oxygen and methylene (-CH2-) functional groups serving as the focal point for the selectivity of the donation and acceptance of electrons between the metal and the pyrimidine molecules as (ω+) electron accepting power and (ω−) electron donating power complement each other. The adsorption efficiency of the molecules as obtained by the simulated molecules was in the order PTA>CTA>ATP>TZP. Selectivity of the molecules was observed as the thiazepine molecules donate electrons more to p-orbital of the Al (110) surface
MHD natural convection in a cavity partially heated having a wavy wall and filled with Al2O3-water nanofluid
Get PDFThis study focuses on the coupling of MHD natural convection in a cavity filled with Al2O3-water nanofluid. The cavity consists of vertical walls maintained at the temperature Tc, while the horizontal ones are adiabatic. The source is fixed at a high temperature Th and one of vertical walls is corrugated. Ansys Fluent software based on finite volume method was used to solve different transport equations through the use of a monophasic model. Several pertinent parameters were considered in the present study, such as Rayleigh number (7.68*104<Ra<3.072*105 ), Hartmann number ( 0<Ha<75), and solid volume fractions ( 0<Th<0.05). The influence of these parameters on heat transfer and flow structure was analyzed by examining streamlines, isotherms, velocity and temperature profiles, and Nusselt numbers. Based on the results obtained, we notice that heat transfer enhancement rises with both Rayleigh number and nanoparticle volume fraction, but it decreases when Hartmann number increases. Also, we note that the conduction heat transfer becomes significant and that by convection becomes limited and sometimes suppressed for high values of the Hartmann
Power quality improvement using series APF based on multi-level (NPC) inverter topologies with intelligent control approaches
Get PDFThis paper presents the performance of novel configuration of series active power filter (Series APF) based on five-level neutral point clamped (NPC) using modified instantaneous reactive power theory control strategy with fuzzy control scheme. The series filter is adopted to decrease voltage harmonics, compensate all voltage disturbances and regulate the terminal voltage of the load. The series APF injects a voltage component in series with supply voltage which is added or subtracted from the source voltage thus maintaining the load side waveforms as pure sinusoidal. Multi-level inverters are currently being investigated and used in various industrial applications. Five-level (NPC) inverter topology is one of the most converters employed in medium and high power applications, their advantages include the capability to reduce the harmonic content and decrease the voltage or current ratings of the semiconductors. On the other hand intelligent techniques know today a great use, due to the advantages that offers compared to conventional techniques. To benefit of these advantages efficient control scheme for series APF using this techniques is proposed in this work. The fuzzy voltage controller is designed to improve compensation capability of series active power filter by adjusting the voltage error using a fuzzy rule. The simulation is performed using MATLAB-Simulink and SimPowerSystem Toolbox. The performance in steady and transient states show the efficiency and the simplicity of the proposed control scheme based on modified p-q control strategy. Before compensation the source voltage is much distorted with high THDv value equal to 46.93%. After compensation using proposed Series APF the THDv is reduced to 3.57% in conformity with 519-IEEE standard norms
Studies on the separation of Uranium from Algerian yellow cake using different processes: impurities determination
Get PDFAnalysis of impurities in uranium materials is crucial for quality control or the purity required by standards in the nuclear industry. This study involves the analysis of impurities in a sample of uranium ore concentrate produced from Tahaggart ore. The instrumental techniques used for the analysis are highly sensitive and susceptible to much interference following the uranium spectrum. Different processes for separating uranium from impurities for comparison were used to quantify them. The uranium sample is an Algerian yellow cake that was digested in nitric acid, separated by solvent extraction using the TBP/CHCl3 system, by extraction chromatography method using tributyl phosphate (TBP) impregnated on the Amberlite XAD-7 resin and by precipitation of uranium with hydrogen peroxide. The raffinate from each process is then analyzed by flame atomic absorption spectroscopy and flame photometry. The concentration of uranium is determined by the Potassium Bichromate method in concentrated solutions and by the Arsenazo III method in raffinates and eluates. Uranium extraction yields are 99.65% using TBP-CHCl3 and exceed 99% using TBP-impregnated XAD-7 resin. The results of the analysis of impurities in Algerian yellow cake after the separation of uranium using different processes show that the contents meet the ASTM C967-13 standard for the elements analyzed except for the iron element. A comparison of the results of the impurities analysis values in Algerian yellow cake by the three separation processes (liquid-liquid extraction (ASTM C761-11), extraction chromatography column, and precipitation) shows the absence of cadmium, titanium, lead, and chromium and the values of the manganese, zinc, and lithium are quite close. The analysis results for the solvent extraction and chromatographic column extraction processes showed that the values of magnesium, copper, and nickel are very close and identical for cobalt. The values of aluminium and iron are close
Effects of desilication and dealumination of NaA zeolite on uranium recovery from aqueous effluents
Get PDFDifferent processes for recovering uranium from raffinates and effluents generated throughout the nuclear fuel cycle are implemented. The adsorption process has been widely adopted in the uranium recovery from aqueous solution, due to its simplicity, rapid kinetics, wide applicability, cost-effectiveness and non-secondary contamination. Adsorption performance is directly determined by the appropriate adsorbents for the target compounds. Zeolite is one of the most commonly used materials for adsorption due to its low cost, high chemical and thermal stability. However, its relatively low sorption capacity limits its performance and feasibility. Many modification strategies have been used to improve its performance. Desilication and dealumination are among the processes that improve accessibility to active sites located inside the zeolite framework and can limit diffusion constraints through the creation of a secondary network of large pores (mesopores) connected to native micropores. In this study, the synthesized and modified NaA zeolite were characterized by powder X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR) and nitrogen adsorption-desorption analysis. Uranium adsorption capacities were found to be around 42 mg/g, 27 mg/g and 10 mg/g for desilicated NaA, NaA and dealuminated NaA respectively. The desilicated NaA material showed better selectivity compared to the starting material. The adsorption of UO22+ ions follows the Langmuir isotherm and the pseudo-second-order kinetic model. The values of uranium desorption 36%, 82% et 87% for NaA, desilicated NaA and dealuminated NaA have been reached using 1M HNO3 for one treatment cycle. The treatment of the real effluent with the three adsorbents showed a recovery of around 62% in uranium for NaA and desilicated NaA, for dealuminated NaA it was around 19% following the coadsorption of competing metal ions