Mechanical and viscoelastic properties of polyethylene-based microfibrillated composites from 100% recycled resources

In this study, recycled polyethylene (rPE) based microfibrillated composites (MFCs) were developed while incorporating recycled poly(ethylene terephthalate) (rPET) and recycled polyamide 6 (rPA) as the reinforcing fibrillar phases at a given weight ratio of 80 wt% (rPE)/20 wt% (rPET or rPA). The blends were first melt processed using a twin-screw extruder. The extrudates were then cold stretched at a drawing ratio of 2.5 to form rPET and rPA fibrillar structures. Next, the pelletized drawn samples were injection molded at the barrel temperatures below the melting temperatures of rPET and rPA. The tensile, three-point bending, impact strength, dynamic thermomechanical, and rheological properties of the fabricated MFCs were analyzed. The effects of injection molding barrel temperature (i.e., 150°C and 190°C) and extrusion melt processing temperature (i.e., 250°C and 275°C) on the generated fibrillar structure and the resultant properties were explored. A strong correlation between the fibrillar morphology and the mechanical properties with the extrusion and injection molding temperatures was observed. Moreover, the ethylene/n-butyl acrylate/glycidyl methacrylate (EnBAGMA) terpolymer and maleic anhydride grafted PE (MAH-g-PE) were, respectively, melt processed with rPE/rPET and rPE/rPA6 blends as compatibilizers. The compatibilizers refined the fibrillar structure and remarkably influenced mechanical properties, specifically the impact strength.     

On theory of electric conductivity of low-conducting liquid in the field of injecting electrodes (mobility dependence)

Calculation of the mobility of free electrons at the injection of electrons from high voltage needle electrodes on a liquid surface is conducted. Applicability of the methods of solid state physics is validated. The dependence of the mobility on the electric field intensity ～E ^?1/3 is achieved on account of the dependence of the free electron wave function on the electric field intensity. It is substantiated that the distribution function with respect to the energies of electrons does not depend on the electric field intensity.     

Optical and solar parameters of irradiated lead–alkali–silicate glass

Lead–alkali–silicate glass that is used for a shielding window of hot cells in nuclear technology has been irradiated by a ⁶⁰Co radioisotope source between 0.998 and 35.939 kGray dose levels. Gamma rays can affect glass and change its several optical and solar parameters such as secondary internal heat transfer factor (q_i), direct solar transmittance (τ_e), solar factor (g) and shading coefficient via the absorbed dose. It is aimed to investigate the performance of the glass in terms of the shading coefficient, which is the most important parameter to view clearly inside of the hot cell. Furthermore, a comparative evaluation has been done with respect to the unexposed lead–alkali–silicate glass. Change in the shading coefficient with respect to absorbed dose is extremely important.     

Benzimidazole-based dendritic nanofiltration membranes

A dendritic-benzimidazole (D-BI) has been prepared using polyphosphoric acid (PPA) as a condensing medium with diaminobenzidine (DAB), 1,3,5-benzene tricarboxylic acid, and isophthalic acid as monomers. The structure of D-BI was ascertained by elemental analysis, FTIR, ¹H NMR, and solid-state ¹³C-NMR. The D-BI was incorporated into polysulphone (PSf) by blending with polyvinylpyrrolidone (PVP K-30) as a macromolecular additive. The membranes were cast by phase inversion technique. The physical properties such as surface morphology and the chemical properties such as contact angle and the performance attributes, such as NOM rejection, salt rejection, and pure water flux were studied. It is imperative that the infusibility of rigid polymeric backbone is overcome by the introduction of polar moieties with no compromise on thermal stability. The membranes displayed substantial increase in thermal stability with D-BI content. The marginal increase in flux has been attributed to the branching and steric effect of D-BI. This is because the introduction of polar group efficiently affords to stabilize the adjacent aromatic rings. The salt rejection shows the order of MgSO₄ ≈ Na₂SO₄ > MgCl₂ > NaCl, which follows that the divalent ions are rejected more than monovalent ions. The antifouling behaviour was also significant as the irreversible fouling (R_Ir 9%), which was found to be minimal for D-BI-incorporated membrane. The blended membranes exhibited good hydrophilicity, antifouling, and fairly good rejection of salts.     

Simultaneous growth of self-patterned carbon nanotube forests with dual height scales

In this study, we report on a unique, one-step fabrication technique enabling the simultaneous synthesis of vertically aligned multi-walled carbon nanotubes (VA-MWCNTs) with dual height scales through alcohol catalyzed chemical vapor deposition (ACCVD). Regions of VA-MWCNTs with different heights were well separated from each other leading to a self-patterning on the surface. We devised a unique layer-by-layer process for application of catalyst and inhibitor precursors on oxidized Si (100) surfaces before the ACCVD step to achieve a hierarchical arrangement. Patterning could be controlled by adjusting the molarity and application sequence of precursors. Contact angle measurements on these self-patterned surfaces indicated that manipulation of these hierarchical arrays resulted in a wide range of hydrophobic behavior changing from that of a sticky rose petal to a lotus leaf.     

On the theory of dielectric liquid electric conductivity in a field of injecting electrodes (concentration dependence)

Calculation of the free electron concentration in a weakly conducting liquid at injection of electrons from high voltage needle electrodes on the liquid surface is given. Methods of solid state physics have been substantiated and applied. The concentration of free electrons does not depend on the electric field intensity up to prebreakdown voltages.     

Maximum Entropy Power Spectrum Estimation for 2-D Multirate Systems

This paper presents maximum entropy power spectrum estimation of a 2-D information signal given that multirate low-resolution observations are available. Since the exact calculation of the 2-D maximum entropy power spectrum is not practical, we propose an efficient method utilizing slices in the 2-D discrete Fourier transform (DFT) domain and the duality in convex programming. We investigate the properties of our solution and provide numerical examples to demonstrate the performance of the new method.     

Quantitative evaluation of intensifying screen materials in Co-60 radiography for steel parts

To increase of the imaging quality for Co-60 gamma radiography, eight different materials (steel, copper, cadmium, indium, gadolinium, dysprosium, gold and lead) are selected as a front screen, and experiments have been carried out using five different thicknesses of steel parts but the same exposure parameters, except for the front screen materials, for each thickness. For the comparative evaluation of the results, the intensifying effect and resolution are selected as the two main criteria. In addition to them, the cost value of the materials is another comparative criterion. First, the results data which are collected from different experiments with different front screens are set-up according to each criterion. In order to make a rational comparative evaluation for the various data sets, the ‘weighted mean value method’ is used as a multichoice and multicriteria method, and then the results of the experiments are evaluated.     

Investigation of the adsorbate effect on current of preexplosion field emission under high-voltage gas discharge

The effect of adsorbed atoms and polar and nonpolar molecules on the current of autoelectronic emission leading up to gas (in particular, picosecond) discharge is investigated. It is shown that the Fowler-Nordheim equation is applicable in all the cases under consideration. Calculation results for the field-emission current are given with allowance made for adsorbate.