Microstructural design of lead oxide–epoxy composites for radiation shielding purposes

Composite epoxy samples filled with PbO and Pb3O4 were fabricated to investigate the mass attenuation characteristics of the composites to X‐rays in the diagnostic imaging energy range. The effect of density on the attenuation ability of the composites for radiation shielding purposes was studied using a calibrated X‐ray machine. Characterization of the microstructure properties of the synthesized composites was performed using synchrotron radiation diffraction, optical microscopy, and scanning electron microscopy. The results indicate that the attenuation ability of the composites increased with an increase in density. The particle size of WO₃ fillers has a negligible effect on the value of mass attenuation coefficient. Microstructural analyses have confirmed the existence of fairly uniform dispersion of fillers within the matrix of epoxy matrix with the average particle size of 1–5 μm for composites with filler loading of ≤ 30 wt % and 5–15 μm for composites with filler loading of ≥ 50 wt %. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

A Review of Clean-Label Approaches to Chilli Paste Processing

Consumer demand for clean-label food products is increasing. Moreover, the production of ready-to-cook products have begun to include clean-label efforts. Dried chilli, the raw material for chilli paste, is susceptible to contaminants such as mould dirt and pesticides that must be removed to maintain the safety and quality of products. In this review, trends related to processes involved in chilli paste production are highlighted. Improvements in preservation technology and the potential for using a clean-label approach to produce premium-quality chilli pastes were explored. Ultrasound washing and high-pressure processing could be combined as part of a hurdle technique for processing chilli pastes that align with consumer values. Ultrasound washing disinfects and removes dirt pesticides and chemical residues present on dried chillies. High-pressure treatments inactivate microorganisms and enzymes, which could extend the shelf-life of chilli pastes. Additionally, organic acid and garlic can be used as natural preservatives to improve the formulation without using artificial ingredients. This clean-label concept can be integrated into the hurdle strategy to produce chilli paste that fulfils the consumer demand for a safe, naturally nutritional product with an extended shelf-life.     

IPv6 Protocol Analyzer

With the emerging of next generation Intemet protocol (IPv6), it is expected to replace the current version of Internet protocol (IPv4) that will be exhausted in the near future. Besides providing adequate address space, some other new features are included into the new 128 bits of IP such as IP auto configuration, quality of service, simple routing capability, security, mobility and multicasting. The current protocol analyzer will not be able to handle IPv6 packets. This paper will focus on developing protocol analyzer that decodes IPv6 packet. IPv6 protocol analyzer is an application module,which is able to decode the IPv6 packet and provide detail breakdown of the construction of the packet. It has to understand the detail construction of the IPv6, and provide a high level abstraction of bits and bytes of the IPv6 packet.Thus it increases network administrators' understanding of a network protocol,helps he/she in solving protocol related problem in a IPv6 network environment.     

Mechanical and Morphological Properties of PP/LLPDE/NR Blends—Effects of Polyoctenamer

In this study, impact-modified polypropylene (PP) ternary blends based on PP/natural rubber (NR)/linear low-density polyethylene (LLDPE) with ratios of 72/10/18 and 64/20/16 were produced by a twin-screw extruder with polyoctenamer (TOR) as the compatibilizer. The mechanical properties of the blends were determined on injection-molded specimens in tensile, flexural, and impact testing. The impact strength and elongation at break of the blend increased significantly while the flexural modulus and tensile strength decreased slightly with increasing TOR content. The impact strength improved with the increasing TOR due the increase of interfacial adhesion resulting in finer dispersion of the rubbery minor phase in the PP matrix. The improvement in compatibility with the addition of TOR into PP/NR/LLDPE blends is being supported by both scanning electron microscopy (SEM) and dynamic mechanical analysis (DMA).     

Mechanical and thermal properties of SEBS‐g‐MA compatibilized halloysite nanotubes reinforced polyethylene terephthalate/polycarbonate/nanocomposites

In this study, the effect of maleic anhydride grafted styrene‐ethylene‐butylene‐styrene (SEBS‐g‐MA) content on mechanical, thermal, and morphological properties of polyethylene terephthalate/polycarbonate/halloysite nanotubes (PET/PC/HNTs) nanocomposites has been investigated. Nanocomposites of PET/PC (70 : 30) with 2 phr of HNTs were compounded using the counter rotating twin screw extruder. A series of formulations were prepared by adding 5–20 phr SEBS‐g‐MA to the composites. Incorporation of 5 phr SEBS‐g‐MA into the nanocomposites resulted in the highest tensile and flexural strength. Maximum improvement in the impact strength which is 245% was achieved at 10 phr SEBS‐g‐MA content. The elongation at break increased proportionately with the SEBS‐g‐MA content. However, the tensile and flexural moduli decreased with increasing SEBS‐g‐MA content. Scanning electron microscopy revealed a transition from a brittle fracture to ductile fracture morphology with increasing amount of SEBS‐g‐MA. Transmission electron microscopy showed that the addition of SEBS‐g‐MA into the nanocomposites promoted a better dispersion of HNTs in the matrix. A single glass transition temperature was observed from the differential scanning calorimetry test for compatibilized nanocomposites. Thermogravimetric analysis of PET/PC/HNTs nanocomposites showed high thermal stability at 15 phr SEBS‐g‐MA content. However, on further addition of SEBS‐g‐MA up to 20 phr, thermal stability of the nanocomposites decreased due to the excess amount of SEBS‐g‐MA. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42608.     

Mechanical,Thermal and Electrical Properties of Ethylene Vinyl Acetate Irradiated by an Electron-Beam

The effects of electron beam irradiation of (ethylene vinyl acetate) EVA containing 18% vinyl acetate was studied. The EVA sample was then irradiated by using 3 MeV electron beam machine at doses ranging from 120 to 360 kGy in air at room temperature and analyzed for mechanical, thermal and electrical properties. It was revealed by DSC analysis that the crystallinity of the electron-beam radiated EVA decreased slightly as verified by a marginal reduction in the densities and heats of melting. Thermal degradation of EVA occurred through two steps as shown by the thermogravimetric curve with maximum rates of 350 and 450°C, respectively. The results obtained from both gel content and hot set tests showed that under the irradiation conditions employed, the EVA sample cross-linked by the electron beam irradiation, and the degree of cross-linking in the amorphous regions was dependent on the irradiation dose. A significant improvement in the tensile strength of the neat EVA samples was obtained upon electron-beam radiation up to 210 kGy with a concomitant decline in elongation of break. Various electrical properties of EVA such as surface and volume resistance, breakdown voltage and dielectric constant were studied as a function of radiation dose. It was revealed that the surface resistance and volume resistivity of the EVA reaches a maximum at a 190 kGy dose of radiation. No considerable change of breakdown voltage and dielectric constant was observed with increasing irradiation dose. These studies suggest that radiation-cured EVA is more thermally and mechanically stable than pure EVA. Similarly, the results from the electrical properties revealed that surface and volume resistance are higher than pure EVA.     

Cauliflower-like poly(3,4-ethylenedioxythipohene)/nanocrystalline cellulose/manganese oxide ternary nanocomposite for supercapacitor

A cauliflower-like ternary nanocomposite of poly(3,4-ethylenedioxythipohene)/nanocrystalline cellulose/manganese oxide (PEDOT/NCC/MnO₂) was synthesized using one-step electropolymerization technique. The effect of manganese (Mn) concentration on the supercapacitive performance was investigated. The structural and morphology studies were conducted using field emission scanning electron microscope, Fourier transform infrared spectroscopy, Raman spectroscopy, and X-ray diffraction. The morphology of ternary nanocomposite at an optimized concentration of Mn resembles the cauliflower-like structure. The two-electrode electrochemical analysis of a ternary nanocomposite PEDOT/NCC/MnO₂ exhibited a higher specific capacitance of 144.69 F/g at 25 mV/s in 1.0 M potassium chloride compared to PEDOT/NCC(63.57 F/g). PEDOT/NCC/MnO₂ ternary nanocomposite was able to deliver a specific power of 494.9 W/kg and 10.3 Wh/kg of specific energy at 1 A g⁻¹ and retained 83% of initial capacitance after 2,000 cycles. These promising results from the incorporation of Mn displayed great prospective in developing PEDOT/NCC/MnO₂ as an electrode material for supercapacitor.     

Calcium ion-selective electrode based on the facile synthesis of CuO over Cu wires

Here, we report a simple, cost-effective and repeatable process to grow copper(II) oxide (CuO) over a Cu wire. Characterization of the prepared CuO structures revealed a pure phase of CuO with high-density nanostructures. By applying dibenzo-18-crown-6 as an ionophore, CuO (as a solid contact, SC) was developed into a calcium (Ca²⁺) ion-selective electrode (ISE) with a linear activity range between 10 μM and 100 mM, an average Nernstian slope (sensitivity) of 32.3?±?1.3 mV/decade, and a lower limit of detection (LOD) of 10 μM. When tested for selectivity among three ions (magnesium, nickel, and sodium) in addition to the target ion, the electrode had better selectivity toward Ca²⁺ ions. We were able to demonstrate that the proposed Cu/CuO electrode was stable within the pH range from 5.0 to 9.0 for a period of 60 days. Our results of the proposed SC-ISE exhibit a good potential response and acceptable stability, and they show a clear indication that Cu/CuO nanostructures (SC-ISE) can be used as an ion-to-electron transducer for low-cost solid-state potentiometric sensors.