CuIns2/Cus Nanocomposite: Synthesis via Simple Microwave Approach and Investigation Its Behavior in Solar Cell

CuInS₂/CuS nanocomposite were synthesized by a copper complex, [bis(ethylenediamine)copper(ΙΙ)] sulfate. Eight sulfur sources were used for this experiment. The products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray analysis spectroscopy, and room temperature photoluminescence spectroscopy. Thin film of nanocomposite powder was fabricated and its feature (V_oc, J_sc and FF) was calculated by current–voltage (I–V) curve.     

Effect of plate-like glass fillers on the mechanical properties of dental nanocomposites

In this study, glass flakes were incorporated into the spherical nanosilica component of the dental composites and its effect on the mechanical properties of these composites was investigated. To achieve a good interfacial adhesion between matrix resin and fillers, the particles were surface treated with a silane coupling agent (γ-MPS). Composites with different plate-like and spherical nanoparticle contents were prepared and their mechanical properties, including flexural strength, flexural modulus and fracture toughness were measured. The morphology of the particles and fracture surface of the composites were studied by SEM. The distribution of the flakes in the composite was also monitored using EDXA. Statistical analysis of the data was performed with ANOVA and the Tukey’s post hoc test was at a significance level of 0.05. The results showed that the flexural modulus and fracture toughness of specimens were improved with increasing the glass flake content up to 15 vol % which then declined upon further increase due to the stacking of the flakes on each other. A good interfacial adhesion was observed between matrix resin and particles in the SEM micrographs. The results of this study suggest that incorporation of glass flakes into the dental composites containing spherical nanosilica particles may enhance their mechanical properties.     

Mechanical and high velocity impact performance of a hybrid long carbon/glass fiber/polypropylene thermoplastic composite

This research explores mechanical and high velocity impact response of hybrid long carbon/glass fiber-reinforced polypropylene thermoplastic composites (HLFT) with different fiber lengths. The work examines three hybrid long fiber thermoplastic composites, i.e., 5, 10 and 20 mm. The HLFTs were prepared by a combination of extrusion and pultrusion processes and using a cross-head die. Tensile and Izod impact tests were carried out to evaluate the mechanical performance of each HLFT compound. A gas gun with a spherical projectile was used to conduct high velocity impact tests at three velocities of 144, 205 and 240 m/s. The results showed that internal mixing operation caused extensive reduction in fiber length of all three LFT lengths. Tensile strength, modulus and Izod impact test results were the indications of higher values with increase in HLFT length. Comparison of these results for the HLFT with that of corresponding glass/PP LFTs, adopted from earlier work by Shayan Asenjan et al. (J Compos Mater 53:353–360, 2019), showed better performance of HLFT. The high velocity impact results showed a steady higher impact performance with the increase in HFLT fiber length for all impact velocities tested. Comparison of HLFT high velocity impact performance revealed better results for all impact velocities tested with that of the corresponding glass/PP LFT composite.     

A method to modify coordinates of detectors in positron emission tomography systems

A new method to modify coordinates of detectors in any positron emission tomography (PET) system using a radioactive point source is developed. This method is based on selecting a centered detector in each detector block of PET and measuring coincidence counts between the two centered detectors in opposite detector blocks to find the coordinates of their LOR (Line of Response). Due to slight misalignment of detector positions, measured LORs may not intersect at a single point. Based on the proposed method, the coordinates of detectors can be measured with very high accuracy and the coordinate of the center of the gantry (which is normally the same as the center of field of view) can be defined correctly. The results of the application of our method to a small animal PET system (FinePET), which was recently developed at Tohoku University, Japan, are shown here. The method is expected to contribute to the design and development of PET systems which can realize a very high spatial resolution of less than 1 mm FWHM.     

Investigation on the resistance spot-welded austenitic/ferritic stainless steel

In this work, the effect of weld current on joining capability of austenitic stainless steel (AISI 304) and ferritic stainless steel (AISI 430) sheets with application of resistance spot welding process was investigated. Macrostructure, microstructure, microhardness, tensile shear strength, and failure mode of welded materials were evaluated for different weld currents. The values of weld current were 2.5, 3.75, and 5 kA. It was found that when the weld current increased, the nugget size and the weld strength were increased. Two distinct failure modes including interfacial and pullout were observed during tensile shear test. Finally, an adequate weld current was obtained.     

Development of electrically conductive hybrid nanofibers based on CNT‐polyurethane nanocomposite for cardiac tissue engineering

Conductive nanofibers have been considered as one of the most interesting and promising candidate scaffolds for cardiac patch applications with capability to improve cell–cell communication. Here, we successfully fabricated electroconductive nanofibrous patches by simultaneous electrospray of multiwalled carbon nanotubes (MWCNTs) on polyurethane nanofibers. A series of CNT/PU nanocomposites with different weight ratios (2:10, 3:10, and 6:10wt%) were obtained. Scanning electron microscopy, conductivity analysis, water contact angle measurements, and tensile tests were used to characterize the scaffolds. FESEM showed that CNTs were adhered on PU nanofibers and created an interconnected web‐like structures. The SEM images also revealed that the diameters of nanofibers were decreased by increasing CNTs. The electrical conductivity, tensile strength, Young's modulus, and hydrophilicity of CNT/PU nanocomposites also enhanced after adding CNTs. The scaffolds revealed suitable cytocompatibility for H9c2 cells and human umbilical vein endothelial cells (HUVECs). This study indicated that simultaneous electrospinning and electrospray can be used to fabricate conductive CNT/PUnanofibers, resulting in better cytocompatibility and improved interactions between the scaffold and cardiomyoblasts.     

Mechanical characterization of graphene oxide reinforced epoxy at different strain rates

Strain rate has significant effect on mechanical behavior of the thermoset polymers. The rate sensitivity is more complicated for thermoset nanocomposites, which compose of two quite different types of materials. Nanofiller‐reinforced epoxy resin is widely used in the industry. In the present work, epoxy resin is reinforced by 0.05 to 0.7 wt% nanographene oxide (GO). The strain rate sensitivity of the fabricated nanocomposites is investigated through compressive test carried out at the strain rates of 0.001–1,900 s^?1. The stress–strain curves of the nanocomposites indicated considerable difference between the low‐strain and high‐strain‐rate responses of the specimens. The results showed that the compressive strength of the nanocomposites was improved by more than 100% at high strain rates with respect to the low strain rates. Also, the addition of nano‐GO had influence on compressive strength enhancement but not as significant as the effect of strain rate. It was observed that the effect of GO was less important for higher strain rates. The experimental compressive strength and modulus of elasticity of the nanocomposites were casted in empirical relations for low and high strain rates for various filler weight percentages. Scanning electron microscopy was also used to examine the quality of GO dispersion. POLYM. ENG. SCI., 59:1636–1647 2019. © 2019 Society of Plastics Engineers     

Preparation and characterization of a novel calcium-conducting polymer inclusion membrane: Part I

The preparation and characterization of a novel type of castor oil-based polymer inclusion membrane (PIM) was investigated, focusing on its flux and selective recovery of Ca²⁺ over competitive ions such as K⁺, Na⁺, and Mg²⁺. The PIM contains a cross-linked high-molecular-weight green polyol (GPO) as a polymer base, benzene-18-crown-6 as a carrier, and an ionic liquid called 1-Butyl-3-methylimidazolium chloride as a plasticizer. GPO was first synthesized by a reaction between an epoxidized castor oil and a cellulose acetate, thereafter, cross-linked by isophorene isocyanate. The base polymer and the prepared PIM were characterized by gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), atomic force microscopy (AFM), thermogravimetric analysis (TGA), and X-ray diffraction (XRD). The FTIR results indicate that oxirane groups in the epoxidized castor oil molecules reacted with the primary hydroxyl groups of cellulose acetate chains. The contact angle measurement hints at the hydrophobic characteristics of the prepared membrane. Compared to the PVC-, CA-, and PVDF-based polymer inclusion membrane, the cured GPO-based PIM, showed higher selectivity and flux of calcium ions with the same composition. The greater stability and significantly higher surface roughness are further favorable features of the novel PIM.