Possible use of volcanic ash as a filler in polyphenylene sulfide composites: Thermal,mechanical, and erosive wear properties

It is a common practice to use particle materials as fillers to improve engineering properties of polymer composites and to lower the cost of final products. There is an obvious cost advantage of compounding volcanic ash (VA) in polymers, either to replace traditional fillers. This study is concerned with thermal, mechanical, and erosive properties of VA‐filled polyphenylene sulfide (PPS) composites. Composite samples containing VA particles at various concentrations (0, 2.5, 5, 10, 15, and 20 wt%) were manufactured by twin screw extruder and injection molding machine. Thermal properties were investigated by thermogravimetric and dynamic mechanical analysis methods. Erosive wear properties were investigated by performing solid particle erosion tests at 30º and 90º impingement angles. The mechanical properties such as flexural strength and modulus of uneroded samples and residual flexural strength and modulus of eroded composite samples were determined by three‐point bending tests. Results show that thermal, mechanical, and residual mechanical properties of the PPS composite were significantly improved by adding VA, although erosion resistance was decreased markedly. It was concluded that VA can be used as a reinforcement in PPS composites to improve thermal and mechanical properties and to reduce the cost of the PPS composites. POLYM. COMPOS., 35:1826–1833, 2014. © 2014 Society of Plastics Engineers     

Utilization of MR angiography in perfusion imaging for identifying arterial input function

Magnetic Resonance Materials in Physics, Biology and Medicine - This research utilizes magnetic resonance angiography (MRA) to identify arterial locations during the parametric evaluation of...     

Nanocomposites of polymer gel electrolyte based on poly(ethylene glycol diacrylate) and Mg–Al layered double hydroxides

The present paper describes the synthesis and characterization of nanocomposite materials composed of the polymer gel electrolyte and a layered double hydroxide (LDH) inorganic filler. Mg–Al LDHs were prepared with various ratios of Mg/Al. It was observed that the layered structure of Mg–Al LDH was totally exfoliated by the PEGDA. The ionic conductivity and mechanical strength were highly improved in the nanocomposite systems. In the case of the composite films having 4.5 wt% of the Mg–Al LDH, the ionic conductivity reached 1.6 × 10^?3 S cm^?1 at room temperature. The incorporation of nanoparticles into the gel resulted in a two‐ or threefold increase in the tensile modulus. Copyright © 2004 Society of Chemical Industry     

Preparation of polyester resin/graphene oxide nanocomposite with improved mechanical strength

Graphene oxide (GO) has attracted huge scientific interest due to its unique physical and chemical properties as well as its wide‐scale applicability including facile synthesis and high yield. Here, we report preparation of nanocomposites based on GO and unsaturated polyester resin (PE). The synthesized samples were characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, scanning electron microscopy, thermogravimetric analysis, and tensile strength measurements. A good dispersion of the GO sheets within the resin matrix was observed from the morphological analysis. A significant enhancement in mechanical properties of the PE/GO composites is obtained at low graphene loading. Around 76% improvement of tensile strength and 41% increase of Young's modulus of the composites are achieved at 3 wt % loading of GO. Thermal analysis of the composite showed a noticeable improvement in thermal stability in comparison to neat PE. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Fabrication of a novel micro-nano fibrous nonwoven scaffold with Antheraea assama silk fibroin for use in tissue engineering

The success of developing artificial organs by tissue engineering depends on scaffold properties and architecture. Here, we describe the fabrication of an Antheraea assama fibroin based novel micro-nano fibrous nonwoven scaffold. The morphological and chemical characterization was done by scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR) respectively, which demonstrated the formation of scaffold with micro-nano architecture. The biocompatibility was assessed in vitro by haemolysis and cytotoxicity assays, whereby the scaffold was found to be nontoxic and efficient in supporting cell adhesion and growth.     

The contribution of wind-hydro pumped storage systems in meeting Turkey's electric energy demand

Renewable energy resources have played an important role to meet increasing energy demand in the world. Among the renewable energy resources, especially, wind energy is of interest due to some advantages, such as being clean, environmental friendly etc. However, the intermittent nature of wind creates several problems to the power system operation and new approaches based on the combined use of wind power and energy storage technologies need to be developed. One of these combined systems is wind-hydro pumped storage systems. In this paper, hydropower and wind energy potential of Turkey are investigated in details. Besides, the importance and the necessity of wind-hydro pumped storage systems for Turkey are comprehensively examined and finally, the contribution of wind-hydro pumped storage systems is emphasized in meeting Turkey's electric energy demand.     

Various skin impedance models based on physiological stratification

Transdermal drug delivery is a non‐invasive method of drug administration. However, to achieve this, the drug has to pass through the complicated structure of the skin. The complex structure of skin can be modelled by an electrical equivalent circuit to calculate its impedance. In this work, the transfer function of three electrical models of the human skin (Montague, Tregear and Lykken Model) based on physiological stratification are analysed. Sensitivity analysis of these models is carried out to consider the extent to which changes in system parameters (different types of R and C as described by different models) affect the behaviour of the model. Techniques like normal of derivative and Hausdorff Distance is also used to study and understand the different curves. Comparison is also made with CPE based model. As Montague Model is the most widely used model, Tregear and Lykken Model are compared with it. It can be commented that out of the above observations Tregear Model at Level 3 can be used for establishing the electrical equivalent of human skin due to its simplicity. However, fractional ordered CPE models provide a good approximation. Future prospect lies in developing a model that characterize both biological properties and physiological stratification.Inspec keywords: electric impedance measurement, transfer functions, biological techniquesOther keywords: skin impedance models, physiological stratification, transdermal drug delivery, noninvasive method, drug administration, electrical equivalent circuit, electrical models, human skin, Lykken models, sensitivity analyses, Montague model, Tregear model, CPE models, constant phase element‐based model, Hausdorff distance