Журнал материаловедения и инженерии

The dynamic viscosity of castor oil was measured as a function of shear rate at different temperature ranged from 1.7°C to 62°C. In this study, shear stress and the dynamic viscosity as a function of temperature of castor oil decrease with increasing temperatures. Three and multi-constant formulas were proposed to obtain more suitable prediction of temperature dependence of shear stress and dynamic viscosity of castor oil. The best AAD% was calculated using our proposed formulas to be 0.03%. This work shows that the behavior of castor oil at the temperature ranged from 1.7°C to 62°C is Newtonian behavior by fitting the model of power law.

1,5-Dimethyl-4-((2-methylbenzylidene)amino)-2-phenyl-1H-pyrazol-3(2H)-one (DMPO) was synthesized to be evaluated as a corrosion inhibitor. The corrosion inhibitory effects of DMPO on Zinc-Aluminum alloy in 1.0 M HCl were investigated using open circuit potential (OCP). The results showed that DMPO inhibited Zinc-Aluminium alloy corrosion in acid solution and indicated that the inhibition efficiency increased with increasing inhibitor concentration. Changes in the impedance parameters suggested an adsorption of DMPO onto the Zinc-Aluminum Alloy surface, leading to the formation of protective films. The novel synthesized corrosion inhibitor was characterized using UV-Vis spectral analyses.

An eco-friendly transparent blend for ultraviolet and visible light rays from polysulfone (PSF) and cellulose acetate butyrate (CAB) was prepared by melting and re-molding. Some optical, mechanical, thermal and morphological properties of the blend were studied by means of UV-Vis spectroscopy, dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), scanning electron microscope (SEM) and X-ray diffraction (XRD). The UV-Vis spectroscopy results showed that the blend became more transparent in the ultraviolet region with an increase in CAB concentration, especially at the damage threshold (268 nm). The preferable blend sample contained 0.2% w/w CAB in the PSF/CAB blend, signifying low ultraviolet light absorption while preserving the transparency of the blend. The results also demonstrated that the amount of 0.2% CAB in PSF increased the modulus and thermal stability while decreasing the value of the glass transition temperature.

Two new electrodes were prepared and characterized electrochemically; Zn/NP/Iron and Cu/NP/Iron, for a direct methanol fuel cell (DMFC). Themorphology and structure of the catalyst layer were analyzed by optical microscopy. The catalyst coating layer shows an alloy character. The results show that, the oxidation of methanol is catalysed by the formation of copper oxides on the surface of the Cu / NP / Iron.

Nanoparticles of iron oxide (Fe3O4) were obtained by Coprecipitation with synthesis time of 30, 60 and 90 min. The morphology of the samples was investigated by scanning electron microscopy (SEM) and structural characteristics were obtained by X-ray diffraction (XRD). The crystallite size was calculated from the spectrum X-ray diffraction with the application of the Scherrer equation and Winfit. The crystallite size varied from 4.6 to 14.4 nm when calculated by Scherrer equation and when calculated by the single line ranged from 7.5 to 22.3 nm Winfit. The degree of graphitization was studied by Raman spectroscopy where spectrums were analyzed with different lasers: 514 nm (0.75 mW power used) and 785 nm (1.2 mW power used). The dominant structures of the spectra are in 215, 276, 398, 487, 654 and 1300 cm-1 when using the laser 514 nm. The spectrum produced with laser 514 nm is characteristic peak of magnetite in 654 cm-1. The spectrum produced by laser 785 nm has a peak at 670 cm-1, shifted relative to the laser 514 nm. The spectrum generated by laser 785 nm peaks characteristic of maghemite encountered due to possible oxidation of the sample caused by the high power laser. The experimental results were satisfactory and are according to the survey.

Burnishing is a cold working surface finishing process in which peaks and valleys on machined surfaces deformed plastically by the application of hard and finished ball or roller against to it. Recently burnishing is becoming popular among post finishing processes because of its many advantages along its primary role i.e., increasing surface finish. In this paper the effect of burnishing process parameters on surface roughness and hardness of brass alloy is experimentally investigated. A simple roller burnishing tool was used for the experiential work of the present study, surface test and micro hardness test were used to demonstrate the effects of the burnishing force and feed rate on surface roughness and surface hardness of a brass alloy. The smoothing process under consideration can be performed on standard machine tools without additional reconfiguration tasks. Process is very useful for any workshop and can be carried out without coolant. The results proved that all the parameters have significant effect on the above said two surface characteristics. The results revealed that improvements in the surface finish and increase in the surface hardness are obtained by reduce the burnishing feed and increase the burnishing force.

A novel method to fabricate a micro-scaled meter metallic stamp for imprinting is proposed in this study. Phase transformation film of amorphous Ge2Sb2Te5 (GST) was first deposited on cleaned silicon substrates by using DC sputtering process. The GST film is then irradiated with the femtosecond laser pulse directly through the photomask to photomelt and induces 2D-crystalline marks formed on the original amorphous region. Owing to the varied chemical properties between the amorphous region and crystalline marks, the crystalline marks were etched by using nitric acid mixed with ethanol. It is with this method that a micro-scaled meter metallic stamp was fabricated. Furthermore, the SU-8 polymeric patterns were successfully replicated and easily demolded from the etched GST stamp by using imprinting. Ultimately, with imprinting, the etched GST stamp could successfully replicate and also easily demold the SU-8 polymeric patterns.

In this study, our objective is to describe some properties of Wasia Formation clay as raw materials in various ceramic applications. Clays were analyzed by X-ray diffraction, chemical composition and plasticity. The data collected from these techniques show that the kaolinites are major clay phases. The main oxides in the clayey samples are SiO2 (51-53%), Al2O3 (26.0-28.0%), and Fe2O3 (2.0-3.0%). The accessory minerals detected in the powdered rock are; quartz, dolomite and hematite. This study reveals that the amount of silica is relatively high and a plasticity test shows a medium value. Geotechnical characterization was carried out on the three representative samples of Wasia Formation. Samples were pressed in a rectangular mould and sintered to a temperature ranging from 850 to 1000°C. Firing characteristics (shrinkage, water absorption, loss of ignition, and mechanical resistance to inflection or bending strength) were measured. Mechanical properties characterizations were performed by means of three-point bending tests. The optimum firing temperature of each sample has been established. The maximum bending strength of each sample has been determined. Generally, the chemical and physical properties of investigated clay samples of Wasia Formation indicate their suitability as raw materials for the production of ceramics, Sanitary Ware, Porcelain and Refractories

The current-voltage characteristics for Au/n-Si Schottky diode are generated by simulation. The simulation performed using Newton-Raphson iteration method yields current-voltage characteristics over wide temperature range. The data is analyzed using TDE-mechanism to study the temperature dependence of barrier height and ideality factor. Results obtained from simulation studies show the barrier height and ideality factor are independent of temperature for pure TE-mechanism. Thus the simulation of I-V characteristics is performed by incorporating ideality factor, obtained on the basis of carrier concentration from 1022-1024 atoms/m3. The result of analysis yield barrier height is still independent of temperature but the ideality factor becomes temperature dependent and this dependence of ideality factor on temperature increases with increase in carrier concentration. Further, the temperature dependence of barrier height and ideality factor is discussed and simulation of current-voltage characteristics is performed.

The dynamic shear viscosity of a binary liquid mixture phenol–water has been measured at different temperatures (50.0°C ≤ T ≤ 75.0°C) and different concentrations (0.00% up to 100.00% by weight of phenol). The critical temperature Tc and critical concentration xc are found to be 67.0°C and 33.90% by weight of phenol respectively, the critical mass density ρc is measured to be 0.8952 g/cm3. The critical and background amplitudes of specific heat at constant pressure are calculated to be 78.12 J/kg.K and 85.29 J/kg.K respectively. The pressure derivative of the critical temperature along the critical line ' cT T is calculated to be 9.722 ×10-6 K/Pa. In addition, dynamic shear viscosity of binary liquid mixture phenol–cyclohexane has been measured at different temperatures (14.0°C ≤ T ≤ 30.0°C) and different concentrations (2.00% up to 39.70% by weight of phenol). The critical temperature Tc and critical concentration xc are found to be 17.0°C and 2.70% by weight of phenol respectively; the critical mass density ρc is measured to be 0.7627 g/cm3. The critical and background amplitudes of isobaric thermal expansion coefficient αpc and αpb are calculated to be 8×10-6 K-1, 6×10-4 K-1 respectively. The pressure derivative of the critical temperature ' cT for the binary is calculated to be 2.8572 × 10-8 K/Pa. The universal quantity R+ ξ for the binary liquid critical mixture phenol–water is calculated to be 0.2716 ± 0.0005. In addition, the universal quantity R+ ξ for the binary liquid critical mixture phenol–cyclohexane is calculated to be 0.2699 ± 0.0001. The calculated values of the universal quantity R+ ξ are in a good agreement with the theoretical value of R+ ζ which is equal 0.2710. The two binary liquid critical mixture belong to the class of universality "Two–Scale–Factor Universality".

The physical properties such as: density, refractive index, viscosity, and acidity of samples of olive oil from different geographical locations and heights in Palestine were measured. The measured physical properties are in agreement with the international and local assigned value. The concentration of Al, Cd, Cu, Fe, K, Mg, Mn, Na, Ni, Pb and Zn elements in olive oil samples are measured by inductively coupled plasma mass spectrometry ICP-MS. It was found that Magnesium (Mg) is the most concentrated metal detected (294.738-782.968 μg/g), followed by concentration of sodium (Na) (73.401-390.699 μg/g) and potassium (K) (18.473-168.883 μg/g). Concentrations of iron, copper and lead in Palestinian olive oil don’t agree with concentration of International Olive Council (IOC). The differences in concentration in metals of olive oil depend on several factors among the type of olive tree, storage age, height and geographical location. There is a positive relation between the concentration of metals in olive oil and physical properties as density, refractive index, viscosity, and acidity. The daily intake rate of these metals shows no risk to human health according to US Environmental Protection Agency (EPA).

In this study, olive oil samples of different irrigation system of different regions in Palestine were studied. The density, refractive index, acidity and viscosity of the samples were measured. The acidity of olive oil samples from different location and different irrigation system was measured. The overall results indicate that acidity increase for samples their trees were irrigated by waste water and classified to Lampante oil, and most of the olive oil samples are classified to be ordinary virgin oil. The viscosity of olive oil samples of 2014 crop from different regions was studied. The experimental results of viscosity showed that the viscosity increased for samples were irrigated by waste water. The concentration of some metals in olive oil samples irrigated by waste water was found to be highly concentrated compared with literature values of metals.

This study covers the fabrication and characterization of dye sensitized solar cell using Hyphaene thebaica as the natural dye sensitizer for DSSCs. Ethanol and water in separate container was used as the extracting solvent for the natural dyes. Titanium dioxide (TiO2) was deposited on fluorine doped tin oxide (FTO) conductive glass forming a TiO2 thin film, underwent sintering at 400ºC for 40 minutes. The photo electrochemical performance of the dye sensitized solar cell (DSSC) based on the doum palm pericarp shows open circuit voltage (Voc) of 0.37 V and 0.50 V, and short circuit current density (Jsc) of 0.005 mA/cm2 and 0.010 mA/cm2 for ethanol and water extracts respectively. This study further inspected the fill factor as 0.63 and 0.66 for the ethanol and water extract respectively. The conversion efficiency for the ethanol extract was 0.012% and water extract is up to 0.033% under light intensity of 1000 m/Wm2 (AM 1.5).