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  • Articles  (5,435)
  • Arabian Journal for Science and Engineering  (957)
  • 103786
  • Natural Sciences in General  (5,435)
  • 1
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    Optimization of Combustion Performance of Bioethanol (Water Hyacinth) Diesel Blends on Diesel Engine Using Response Surface Methodology (2015)
    Springer
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    Publication Date: 2015-08-11
    Description: In the current study, an attempt has been made to use water hyacinth plant ( Eichhornia crassipes ) as a raw material for production of bioethanol which is then blended with diesel to obtain biodiesel. To investigate the combustion performance, combustion simulation model was developed and compared with experimental results. Further, the combustion performance of bioethanol–diesel blends in diesel engine was evaluated using response surface methodology technique. Bioethanol extracted from water hyacinth is blended with commercial diesel fuel (BED) in different proportions (volume by volume (v/v)), i.e., 5, 10, 15, 20 and 25BED. This study illustrates the investigation of various compression ratio, loads and fuel injection pressures with different proportion of diesel bioethanol blends. The results show that single-cylinder diesel engine is capable to run up to 25 % bioethanol mixed with diesel by volume. The in-cylinder combustion pressure ( P max ) reduces while increasing bioethanol–diesel ratio. At higher engine loads, compression ratio and fuel injection pressure, bioethanol blends produce higher combustion pressure in comparison with pure diesel fuel. At lower load, compression ratio and fuel injection pressure, ignition delay increases and P max reduces. The 5BED (5 % bioethanol + 95 % diesel) and 10BED (10 % bioethanol + 90 % diesel) gave better combustion performance among all the bioethanol–diesel blends.
    Print ISSN: 1319-8025
    Electronic ISSN: 2191-4281
    Topics: Natural Sciences in General , Technology
    Published by Springer on behalf of The King Fahd University of Petroleum & Minerals.
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  • 2
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    New Green Dielectrics Related to Calcium Titanate: Synthesis and Characterizations (2015)
    Springer
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    Publication Date: 2015-08-11
    Description: The main purpose of the present work is the preparation of green dielectrics by solid-state reaction between two perovskites: CaTiO 3 (CTO) and KMgF 3 (KMF). Calcium titanate and potassium magnesium fluoride powders were previously synthesized, respectively, at 850 °C and 700 °C. Several chemical compositions (1– x ) CTO + x KMF were then prepared and dry-milled. The mixtures were pressed into pellets and sintered in free air at 950 °C for 2 h. The obtained ceramics were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analyses (TGA, DTGA) and dielectric measurements (DE). The XRD study revealed the formation of a fluorinated perovskite solid solution with general formula Ca 1– x K x (Ti 1– x Mg x )O 3–3 x F 3 x (CKTMOF) in the initial composition range 0 ≤  x  ≤ 0.20. The diffraction peaks of CKTMOF oxyfluorides were indexed in an orthorhombic lattice, and no significant change was observed in the unit cell parameters with increasing KMF amount. On the other hand, the addition of KMF to CTO allowed the ceramic’s densification at low temperature. The shrinkage increased from 1.9 % ( x  = 0) to 9.5 % ( x  = 0.20), and the grain’s size of the various ceramics was in the range 0.5–5μm. Several thermal phenomena were detected by DSC and DE. No weight loss and no peak were depicted on the TGA and the DTGA curves over all the temperature range investigated; therefore, the phenomena observed by DSC and DE could be ascribed to phase transitions. These dielectrics could be of interest for the fabrication of class I capacitors; however, the losses have to be improved.
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    Topics: Natural Sciences in General , Technology
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  • 3
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    Adaptive Switching Non-local Filter for the Restoration of Salt and Pepper Impulse-Corrupted Digital Images (2015)
    Springer
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    Publication Date: 2015-08-12
    Description: The paper presents an effective nonlinear adaptive switching non-local filter for the restoration of impulse-corrupted digital images by using distinct impulse detection and correction stages. The correction scheme of the filter adaptively switches between details-preserving non-local mode and signal restoration-based local mode to facilitate high fidelity in the restored image. The non-local filtering operation replaces impulses with a remote pixel that better suits the local image conditions. The algorithm works in this non-local mode only when there are sufficient uncorrupted pixels in the local neighborhood of the corrupted pixel to be replaced. Otherwise, the algorithm replaces impulsive pixels with the median of the uncorrupted pixels from the local neighborhood. Experimental results from various impulse noise levels support the improved performance of the proposed algorithm over other algorithms both subjectively and objectively.
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    Electronic ISSN: 2191-4281
    Topics: Natural Sciences in General , Technology
    Published by Springer on behalf of The King Fahd University of Petroleum & Minerals.
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  • 4
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    Evaluation of High-Temperature Oxidation Behavior of Inconel 600 and Hastelloy C-22 (2015)
    Springer
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    Publication Date: 2015-08-13
    Description: The aim of this study was to investigate the oxidation behavior of nickel-base superalloys (Inconel 600 and Hastelloy C-22) by the determination of the oxidation rates of alloys at elevated temperatures and at ambient air. The cyclic oxidation method was adapted by heating of alloys periodically in still air at 900, 1000 and \({1100^\circ{\rm C}}\) followed by cooling at ambient temperature. The weight change measurement was recorded during the cyclic oxidation tests. The X-ray diffraction and microstructure study were also used as characterization methods to illustrate the properties of studied alloys and oxide film that formed on the surface of oxidized alloys. Inconel 600 and Hastelloy C-22 showed their ability to develop a uniform protective oxide film. The oxide film that formed on both alloys was chromia oxide Cr 2 O 3 with smaller amount of spinel oxide NiCr 2 O 4 . The results of the weight gain measurements suggest that the oxidation kinetics of both alloys follows the parabolic behavior during the experimental tests. Also both alloys at \({1100^\circ{\rm C}}\) exhibited severe spallation of oxide film with linear decreasing in the weight change measurements. The p-kp model was implemented to describe the subsequent cyclic process of oxide growth and spalling.
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    Topics: Natural Sciences in General , Technology
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  • 5
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    Prediction of the Levels of Contamination of HV Insulators Using Image Linear Algebraic Features and Neural Networks (2015)
    Springer
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    Publication Date: 2015-08-13
    Description: Contaminated high-voltage (HV) insulators in polluted areas may lead to flashovers if they are not cleaned periodically. Flashover often leads to lengthy service outages and thus has a considerable impact on power system reliability. Therefore, an accurate prediction of the contamination level of HV insulators is vital. In this study, a MATLAB-based algorithm for predicting the contamination level is proposed. The algorithm uses the extracted features (in this work, linear algebraic features) from images captured by digital cameras as an input to a neural network. When compared to existing methods reported in the literature, the designed neural network correlates successfully the captured insulator images and the contamination level when tested on unseen insulators.
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  • 6
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    Analytical- and Simulation-Based Analysis for Optimum Erbium-Doped Fiber Amplifier (EDFA) Performance (2015)
    Springer
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    Publication Date: 2015-08-13
    Description: In this paper, analytical and simulation models were used to analyze the performance of the erbium-doped fiber amplifier in terms of its pump power, erbium-doped fiber length, overlap factor, erbium ions concentration, and input signal power. The analytical-based analysis was performed using MATLAB software, whereas the simulation-based analysis was performed using Optisystem software. Both the analytical- and simulation-based results agreed well. For example, both confirmed the followings: Maximum gain can be reached at a shorter fiber length as the overlap factor and erbium ions concentration increase; the gain is independent of the pump power at values of erbium-doped fiber lengths ≤10m; that almost equal erbium-doped fiber gains can be obtained as the pump power approaches its highest value and that the gain seems to be equal at low values of input signal powers; however, it starts to saturate as the input signal power increases.
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    Topics: Natural Sciences in General , Technology
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  • 7
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    Fabrication of Hybrid Mg/(Al 2 O 3p + SiC p  + Gr p ) Metal Matrix Composite on Developed Gas Injection Liquid Stir Casting Setup (2015)
    Springer
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    Publication Date: 2015-08-13
    Description: This paper presents the fabrication process of hybrid Mg/(Al 2 O 3p + SiC p + Gr p ) metal matrix composite on developed gas injection liquid stir casting setup. In this study, the microstructure, grain morphology and the presence of elements in fabricated composite are investigated through high-resolution scanning electron microscope and X-ray diffractometer. A gas injection liquid stir magnesium metal matrix composite casting setup has been designed, fabricated and utilized for the purpose. Different sets of experiments have been performed in a controlled environment of argon gas. Different tests have been conducted on the prepared Mg-MMC to investigate its physical and mechanical properties of the prepared MMC. The test results reveal that the micro-hardness of hybrid Mg/(4wt% SiC p + 2wt% Al 2 O 3p + 1wt% Gr p ) MMC is about 1.5 times of the pure Mg-matrix. Tensile strength of fabricated hybrid Mg/(8wt% SiC p + 2wt% Al 2 O 3p + 1wt% Gr p )-MMC has also increased to 1.4 times of pure Mg-matrix. From the results, it is concluded that the developed gas injection stir Mg-MMC casting setup can be effectively utilized for the fabrication of hybrid Mg/(Al 2 O 3p + SiC p + Gr p )-MMC and can be used for many industrial and engineering applications.
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    Topics: Natural Sciences in General , Technology
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  • 8
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    Prediction of Accurate Values for Outliers in Coal Drying Experiments (2015)
    Springer
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    Publication Date: 2015-08-13
    Description: Coal drying is a quite important process from both burning efficiency and granulation perspective. Therefore, coal drying experimentation processes always attract researchers from various fields. Those experiments are quite costly since they require expensive laboratory equipment and considerable labor hour. Even if the costs of experiments are tolerable, often long experiment periods and large number of experimentation will cause serious problems for prompt academic results. During the analysis of experiments, researchers convert the results into graphical form. However, when creating charts, it is observed that some of the results diverge from the others abnormally marking some measurement as outliers. In such cases, experiments should be repeated to eliminate the effects of these abnormalities. Due to high costs and time constraints, repetition of an experiment is not preferable in general. To predict the accurate values for outliers and overcome issues generated by these abnormalities, artificial neural network (ANN) is employed in this study and tolerable deviations and acceptable experimental costs are reached by using ANN.
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    Topics: Natural Sciences in General , Technology
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  • 9
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    Study of the Delamination in the Case of Piezoelectric Bimorph Beams “Static Behavior” (2015)
    Springer
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    Publication Date: 2015-08-13
    Description: The first-order shear deformation theory is used to study the static behavior of a piezoelectric bimorph beam with delamination between its layers. This delamination is taken with several lengths and locations along the beam with different boundary conditions. The results show that the shape of the axial displacement field is not affected by either the length of the debonded zone or the variation in the ambient. However, this shape is deformed when an electrical field is applied.
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  • 10
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    Fuzzy Decoupling Control of Greenhouse Climate (2015)
    Springer
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    Publication Date: 2015-08-13
    Description: Greenhouses are complex and nonlinear systems in which the inside temperature and humidity are deterministic parameters for the optimal growth of the plants. Several control methods have been developed to get an optimized microclimate. Physically both parameters are strongly coupled; hence, this paper proposes a novel fuzzy controlling method considering the temperature and humidity’s coupling effects; the controller is based on a validated greenhouse physical model and an evaluation of the correlation of both parameters. The results show the high performance of the decoupling method and the effectiveness of the fuzzy controller to manage the inside climate while saving energy.
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    Topics: Natural Sciences in General , Technology
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