Liquid–Liquid Equilibria in Biodiesel Production

During biodiesel production, the product is contaminated with impurities such as some non-reacted alcohol, glycerol, and catalyst. In order to comply with product requirements, these impurities must be removed, for example, by washing with water. Knowledge of the extent of water solubility in biodiesel is required to design the drying system and determine fuel quality. In the present work, the solubilities of water in biodiesels produced from sunflower and canola oils were measured within the temperature range of 24–60 °C. The solubility of water increased with increasing temperature and biodiesel unsaturation. The liquid–liquid equilibria of ternary systems of glycerol, methanol, and the above-mentioned biodiesels were investigated experimentally at 20, 30, and 40 °C. The binodal curves were determined by using the cloud point titration method and the tie lines were measured by evaporating the methanol. Both binary and ternary data were modeled using the UNIQUAC model. The model showed good agreement with the data. Othmer-Tobias correlations were applied and the corresponding constants were obtained. The results validated the consistency of the tie-line data obtained experimentally.     

An energy-aware scheduling of dynamic workflows using big data similarity statistical analysis in cloud computing

The Journal of Supercomputing - Cloud computing is a suitable platform for workflows that work with massive data and big data. Through virtualization, cloud computing converts physical...     

The Effect of Temperature Dependency of Surface Emissivity in 1-D and 2-D Nonlinear Heat Radiation Equations

Knowledge of the temperature dependency of the physical properties such as surface emissivity, which controls the radiative problem, is fundamental for determining the thermal balance of many scientific and industrial processes. The surface emissivity generally depends on surface temperature, wavelength, surface material geometry (curvature, roughness), and direction of observation, and often changes with oxidation, melting, coating, and even surface pollution. Current work studies the influences of temperature dependency of surface emissivity on heat transfer in a lumped system. The problem was investigated for both one-dimensional (1-D) and two-dimensional (2-D) systems. For 1-D equations, two recent analytical methods called the homotopy perturbation method (HPM) and parameterized perturbation method (PPM) are presented. Unlike classic perturbation methods, these techniques do not need small parameters for nonlinear heat transfer equations. Thus, we can apply them for large values of surface emissivity. For the 2-D domain, a finite-element code is used to obtain the unsteady distribution of temperature. Three different functions were chosen to describe the thermal behavior of surface emissivity. The solutions of 1-D nonlinear equations are compared with the accurate numerical fourth-order Runge–Kutta method, and excellent agreement (maximum error of 0.0021%) was observed. The capabilities of employed analytical methods are discussed and it is shown that HPM needs fewer series terms in comparison with PPM. For both 1-D and 2-D equations, it is illustrated that the temperature gradient increased by adding to the order of emissivity variation versus temperature.     

Mechanical, electrical, and thermal properties of irradiated low-density polyethylene by electron beam

The effect of electron-beam (EB) irradiation on the mechanical, electrical, and thermal properties of low-density polyethylene (LDPE) was studied The LDPE was irradiated by using 3?MeV EB machine at doses ranging from 25 to 250?kGy in air at room temperature and analyzed for mechanical, thermal, and electrical properties. It was revealed by differential scanning calorimetry analysis that the crystallinity of the EB-radiated LDPE decreased slightly as verified by a marginal reduction in the densities, enthalpy, and melting points. Thermogravimetric analysis test showed that the thermal degradation of LDPE improved by increasing irradiation. The results obtained from both gel content and hot set tests, indicating whether the applicable LDPE has been properly cross-linked or not, showed that under the EB irradiation conditions employed, the cross-linking of the LDPE samples occur mainly in the amorphous region, and the cross-linking density at each irradiation dose depends almost on the amorphous portions of the LDPE. A significant improvement in the tensile strength of the neat LDPE samples was obtained upon EB up to 250?kGy with a concomitant decline in elongation at break. The results on the electrical properties revealed that the surface resistance, volume resistivity, and dielectric strength of the LDPE increase with irradiation dose and reaches a maximum at a 250?kGy irradiation dose. No considerable change of breakdown voltage, dielectric constant, and dielectric loss factor were observed with increasing irradiation dose. The enhancement in the heat deformation, hardness, and thermal aging properties of LDPE upon EB irradiation, suggests that irradiated LDPE is more thermally and mechanically stable than virgin LDPE.     

Effect of Graphene and Carbon Nanotube on Low‐Density Polyethylene Nanocomposites

The nanocomposites of low‐density polyethylene contain graphene (LDPE/Gr) and low‐density polyethylene contains carbon‐nanotubes (LDPE/CNTs) with different Gr loadings (0.5, 1, and 3 wt%) were formulated with a melt‐mixing method. The distribution of Grs in LDPE was detected by scanning electron microscopy. In this study, morphological, electrical, thermal, tensile, and rheological properties of nanocomposites were comparatively investigated. The outcomes were reviewed and it was recognized that LDPE/Gr nanocomposites reveal superior properties than LDPE/CNTs nanocomposites at the same loadings. The superior performance of LDPE/Gr nanocomposites attributes to the large aspect ratio of Gr and its two dimensional flat surfaces which effect in increasing physical interlinking with LDPE chains and expanded the interface zone at filler–LDPE interface. It was also identified that the achieved results for LDPE/CNT nanocomposites, which has a compact surface area and linkage with LDPE, are less noticeable than similar Gr compounds due to higher interfacial interactions between Gr and LDPE. The thermomechanical results of LDPE/Gr nanocomposites have been studied and the influence of nanoscaled strengthening in the thermoplastic matrix has been investigated. The existence of Gr limits the flexibility of LDPE chains, increases the rigidity and the strength of the LDPE‐nanocomposites. This study compares how a flat or roll structure of carbon nano‐structure additive (Grs vs. CNTs) can change the various properties of LDPE nanocomposites. J. VINYL ADDIT. TECHNOL., 25:35–40, 2019. © 2018 Society of Plastics Engineers     

Electron beam irradiation of low-density polyethylene filled with metal hydroxides for wire and cable applications

The effects of electron beam irradiation for crosslinking of polymers used for wire and cable insulations are still being researched. In this research, the influence of electron beam irradiation on the different blends of low-density polyethylene (LDPE) filled with aluminum trihydrate and magnesium hydroxide (ATH, MH) were studied. It was revealed by melt flow index, tensile strength, and elongation at break tests that addition of MH to LDPE increases the adhesion forces inside polymer matrices more efficient than similar ATH/LDPE compounds. Field emission scanning electron microscopy test showed that MH is platy in structure and more homogenous mixed than ATH with LDPE. The results on thermogravimetric analysis and limiting oxygen index tests revealed that the thermal stability and incombustibility properties of MH blends are more efficient than similar ATH blends. Meanwhile, it was observed by smoke density test that MH blends produce the lowest smoke density compared with virgin LDPE and similar ATH blends. It was also observed that increasing irradiation by electron beam had impressive affections on the density, gel content, and mechanical properties for all the polymeric samples in this study.