744 research outputs found
Similarity Solutions for a Steady MHD Falkner-Skan Flow and Heat Transfer over a Wedge Considering the Effects of Variable Viscosity and Thermal Conductivity
An analysis is carried out to study the Falkner–Skan flow and heat transfer of an incompressible, electrically conducting fluid over a wedge in the presence of variable viscosity and thermal conductivity effects. The similarity solutions are obtained using scaling group of transformations. Furthermore the similarity equations are solved numerically by employing Kellr-Box method. Numerical results of the local skin friction coefficient and the local Nusselt number as well as the velocity and the temperature profiles are presented for different physical parameters
Sol–Gel Synthesis of Iron-Doped Sepiolite as a Novel Humidity-Sensing Material
Nowadays, humidity sensors are attracting a great deal of attention, and there are many studies focusing on enhancing their performances. Nevertheless, their fabrication through facile methods at reasonable cost is a significant factor. In this article, a new magnesium silicate nanopowder was successfully synthesized using a simple and low-cost sol–gel method. Subsequently, modified sepiolite was achieved by the substitution of iron ions in the synthesized nanopowders. The specimens were then characterized by X-ray diffraction, field emission–scanning electron microscopy, X-ray photoelectron spectroscopy, thermogravimetric–differential thermal analysis, infrared spectroscopy, and nitrogen adsorption. Furthermore, humidity sensors were manufactured by screen printing the prepared powders on alumina substrates with interdigitated Pt electrodes. The results showed that the fabricated sensors with modified sepiolite exhibited interesting characteristics for humidity detection
Data mining: a tool for detecting cyclical disturbances in supply networks.
Disturbances in supply chains may be either exogenous or endogenous. The ability automatically to detect, diagnose, and distinguish between the causes of disturbances is of prime importance to decision makers in order to avoid uncertainty. The spectral principal component analysis (SPCA) technique has been utilized to distinguish between real and rogue disturbances in a steel supply network. The data set used was collected from four different business units in the network and consists of 43 variables; each is described by 72 data points. The present paper will utilize the same data set to test an alternative approach to SPCA in detecting the disturbances. The new approach employs statistical data pre-processing, clustering, and classification learning techniques to analyse the supply network data. In particular, the incremental k-means
clustering and the RULES-6 classification rule-learning algorithms, developed by the present authors’ team, have been applied to identify important patterns in the data set. Results show that the proposed approach has the capability automatically to detect and characterize network-wide cyclical disturbances and generate hypotheses about their root cause
Kinetic Simulation of He radio frequency capacitive coupled plasma
Radiofrequency capacitively coupled plasma is studied theoretically using a
Particle-in-Cell code. For He discharge, the time-averaged sheaths are in the
range of few centimeters. The sheath potential, ion, and electron energy and
angular distributions, discharge current, and dissipated power depend on the
driven potentials and frequencies. Increasing the amplitude of the high radio
frequencies increases the bulk density and the sheath potential and,
consequently, increases the plasma processing rate. Increasing the intermediate
radio frequency amplitude allows a wider sheath with a broad ion energy
distribution and a narrower ion angular distribution. Changing the amplitude
and the phase shift between driven frequencies provide different energies and
angular distribution allowing performing various processes. The interplay
between the sheath and bulk dynamics in the intermediate radiofrequency regime
and the high-frequency regime may excite harmonics in the discharge current
Effect of Hydrogen on Pristine Amorphous V2O5 Thin Film
Sequentially deposited layer by layer up to five vanadium oxide film is deposited on glass and silica substrates at 300 k by vacuum thermal evaporation technique. The deposited samples subjected to reduction process in the preparation situe by hydrogen gas at 473k for 10 minutes and 573 k for 10, 20 minutes. The XRD investigation of the samples demonstrates that the pristine sample is amorphous while those reduced are crystalline. The existed phases in virgin samples are educated by Raman spectroscopy which indicates the single V2O5 phase. The different phases in the reduced sample are identified by analyzing their XRD patterns. The electrical resistance of the reduced samples is measured as a function of temperature during heating and cooling cycles. The transition temperature from semiconducting to metal state is defined by the derivative of dR/d
Efecto de la radiación gamma sobre el perfil lipídico de los aceites de semillas de soja, cacahuete y sésamo
Seeds of soybean, peanut, and sesame were exposed to various doses of gamma irradiation (0.0, 0.5, 1.0, 2.0, 3.0, 5.0 and 7.5 kGy). Fatty acid and unsaponifiable profiles of the extracted oils were separated by gas chromatography mass spectroscopy. The results demonstrated that the ratios of unsaturated to saturated total fatty acids (TU/TS) and total hydrocarbons to sterols (TH/TSt) were significantly altered upon irradiation. These changes were clearly observed in the oil extracted from irradiated sesame seeds compared with the oils from irradiated peanuts and soybean. The major change in fatty acid composition was the decrease in the quantity of unsaturated fatty acids (C18:1 and C18:2) in all cases. In contrast, the sterol fractions such as cholesterol, campesterol, stigmasterol and β-sitosterol levels of irradiated seeds were generally lower than that of the un-irradiated seeds.Semillas de soja, cacahuete y de sésamo se expusieron a diferentes dosis de radiación gamma (0,0, 0,5, 1,0, 2,0, 3,0, 5,0 y 7,5 kGy). Se determinaron los perfiles de ácidos grasos y el insaponificable de los aceites mediante cromatografía de gases y espectrometría de masas. Los resultados demostraron que las relaciones de ácidos insaturados a ácidos grasos totales saturados (TU/TS) e hidrocarburos totales a esteroles (TH/TSt) se alteró significativamente tras la irradiación. Estos cambios se observaron claramente en el aceite extraído de las semillas de sésamo irradiados, en comparación con los aceites de soja y cacahuetes irradiados. El mayor cambio en la composición de ácidos grasos fue la disminución de la cantidad de ácidos grasos insaturados (C18:1 y C18:2) en todos los casos. En contraste, los niveles de las fracciones de esteroles como colesterol, campesterol, estigmasterol y β-sitosterol de las semillas irradiadas fueron en general más bajo que el de las semillas sin irradiados
Bond Strength of Concrete Containing Different Recycled Coarse Aggregates
Some of the remnants of construction demolition wastes could be used after recycling as coarse aggregate in concrete industry. Among these wastes are ceramics, shale bricks and hardened concrete. This research was carried out to determine the effect of using such recycled aggregate (RA) as total or partial replacement of the natural dolomite coarse aggregate in concrete mixes on their compressive and bond strength with steel bars. Two types of concrete were investigated in this research which included normal concrete and self-compacted concrete. The main variables taken into consideration wee, the type of concrete, the type and percentage of the recycled aggregate and the age of testing. The consistency of the normal fresh concrete was measured by the slump test. However, the workability and flowability of the self-compacted fresh concrete were measured using slump test, V-funnel test. Out of the experimental test results, equations were predicted which correlated between the concrete compressive strength and bond strength of both the recycled aggregate ordinary concrete and the recycled aggregate self-compacted concrete. These equations were completely different than that of the steel-concrete bond equation of concrete with natural aggregate. Out of this research results, the recycled aggregate concrete could be used in both non structural applications and in some structural applications with special precautions
Lipid profile improving effect of Coriandrum sativum seed extract in rats
Background: Hyperlipidaemia is a common disease in middle-aged and elderly people. It has received attention, as it indirectly affects the normal metabolism, blood viscosity and vital organ functions. It is a risk factor for cardiovascular and cerebrovascular diseases. Therefore, the aim of the present study was to evaluate the possible antihyperlipidemic effect of Coriander sativum seed extract (CSSE) in rats fed on high-fat diet.Methods: A parallel study design was adopted on 42 albino rats, divided randomly into 7 groups with different treatments. After a 6 week-experimental course, blood samples were collected and analysed for lipid and organ function parameters. Phytochemical analysis was conducted on the used seed extract to detect the active principles underlying its effects.Results: CSSE (150 and 300 mg/kg, orally, once daily) along with a high-fat (1.5% cholesterol+1.5% coconut oil, in diet) diet resulted in a significant (p≤0.05) improvement in plasma lipid parameters, including, total cholesterol, triacyglycerols and lipoproteins, compared to the high-fat group. group. The extract significantly (p≤0.05) improved hepatic (total proteins, albumin, globulins, total conjugated and unconjugated bilirubins, AST, ALT, GGT), cardiac (CK-MB and troponin-I) and renal (urea, creatinine & uric acid) biomarkers. Phytoanalysis of CSSE revealed presence of phlobatannin and flavonoids. The protection % produced by small and large doses of CSSE were dose-dependent and parallel to those of the standard antihyperlipidemic rosuvastatin (2 mg/dl orally, daily).Conclusions: These data indicate that CSSE has a marked antihyperlipidemic effect and could be a source for a promising nutraceutical antihyperlipidemic drug depending on its high phenolic and flavonoid content
Survey on the Moisture and Ash Contents in Agricultural Commodities in Al-Rass Governorate, Saudi Arabia in 2017
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