Aluminum supported palladium nanoparticles: Preparation,characterization and application for formic acid electrooxidation

Palladium nanoparticles were fabricated on the aluminum electrode (Pd/Al) by electrodeposition method through a single step potential from an aqueous solution of 1 mM Pd(NH₃)₄Cl₂. The electrochemical and physical characteristics of the Pd/Al were investigated by cyclic voltammetry, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) method. Electrochemical measurements in acidic solution indicate that Pd/Al exhibits significantly high electrochemical active surface area (18.32 cm²) with respect to Pd–Al (2.1 cm²) (electroless deposited) and bare Pd (0.28 cm²) electrodes. SEM images and XRD results show that the Pd particles are homogeneously deposited on the surface Al substrate in nanoparticles size between 30 and 50 nm with maximum Pd (111) plane at 2θ angles about of 39°. The Pd/Al was used as electrocatalyst for the oxidation of formic acid (FA) in 0.1 M H₂SO₄ solution. The cyclic voltammetry and chronoamperometry results show that the obtained electrocatalyst, Pd/Al, exhibits high catalytic activity and stability for the electrooxidation of FA. On the other hand, the Pd/Al electrocatalyst has higher catalytic activity for FA oxidation than the comparative Pd–Al and bare Pd electrodes and shows great potential as less expensive electrocatalyst for FA oxidation in direct formic acid fuel cells.     

Investigation of the Neutron Angular Distribution and Neutron Yield on the APF Plasma Focus Device

This paper presents an experimental study of neutron yield as well as neutron angular distribution on the APF plasma focus device. The system operates with pure deuterium gas in varying the filling pressure and working voltages of 11.5 and 13.5 kV. The maximum average of neutron yield is (2.88 ± 0.29 × 10⁸) neutrons per shot at the pressure of 7 torr. The neutron angular distribution is measured with housing an array of seven silver activation Geiger-Muller counters at the angles of 0°, ±30°, ±60°, and ±90° in a distance of 90 cm from the anode tip. The results of neutron angular distribution suggest that the neutron production mechanism may be predominantly beam target model.     

A Study on Plasma Polymerization of Acrylic Acid Using APF Plasma Focus Device

The most conventional way for polymerization of acrylic acid on different substrates is using RF devices and introducing of other devices is under way. In this work we have a new study on formation of polymer Acrylic Acid using APF plasma focus device. The formation of plasma polymer acrylic acid is discussed using results obtained from attenuated total reflectance infrared spectroscopy (ATR). The results show that after 15 shots, nitrogen pulses performed polymerization on the specimens and the main peaks of ATR spectra assured poly acrylic acid formation on SBR substrate.     

High speed,low power VLSI CMOS vision sensor for geometric centre object tracking

In this article an object tracking CMOS sensor is presented. The architecture incorporates photo detection devices and pixel level processing elements for capturing and processing the image data and extracting the object's coordinates. The edges of the image scene are extracted by in-pixel edge detectors and the region (object) of interest, selected by the user, is segmented using a switch network. Coordinates of the desired region are obtained by extracting the geometric centre of the region. Tracking of the selected object is then performed by automatic reselection of the region using the updated coordinates. The proposed design presents less sensitivity to threshold adjustments than binarisation techniques. The sensor has been designed as a 64 × 64 pixel VLSI CMOS chip in the 0.35 μm standard CMOS technology. The proposed structure is analysed with regard to its operation in the presence of mismatches and noise. Features of the sensor are reported and compared with some previous object tracking designs. Because the power dissipation is small, the chip is ideal for low-power applications.     

Security and Privacy Analysis of Song–Mitchell RFID Authentication Protocol

Many applications, such as e-passport, e-health, credit cards, and personal devices that utilize Radio frequency Identification (RFID) devices for authentication require strict security and privacy. However, RFID tags suffer from some inherent weaknesses due to restricted hardware capabilities and are vulnerable to eavesdropping, interception, or modification. The synchronization and untraceability characteristics are the major determinants of RFID authentication protocols. They are strongly related to privacy of tags and availability, respectively. In this paper, we analyze a new lightweight RFID authentication protocol, Song and Mitchell, in terms of privacy and security. We prove that not only is the scheme vulnerable to desynchronization attack, but it suffers from traceability and backward traceability as well. Finally, our improved scheme is proposed which can prevent aforementioned attacks.     

A low-power-consuming SOM for wireless communications

This paper presents theoretical and experimental results of a low-power-consuming hybrid push-pull self-oscillating mixer (SOM) circuit at the UHF frequency band. The frequency-stable SOM circuit is designed and fabricated using matched-pair Si bipolar junction transistors and high-Q resonators, where measured phase noise of this free-running voltage-controlled oscillator is -101.2 dBc/Hz at 100-kHz offset. A 20-dB up-conversion gain, a compression dynamic range (CDR) of 65 dB·MHz, and a spurious-free dynamic range of 50 dB·MHz ^2/3 are also measured for the mixer portion of this SOM. Moreover, a down-conversion gain of ≈-2 dB with a CDR of 100 dB·MHz is also measured     

On the modeling of bending responses of graphene-reinforced higher order annular plate via two-dimensional continuum mechanics approach

This research presents bending responses of FG-GPLRC plates based upon higher order shear deformation theory (HSDT) for various sets of boundary conditions. The rule of the mixture and modified Halpin–Tsai model are engaged to provide the effective material constant of the composite layers. By employing Hamilton’s principle, the governing equations of the structure are derived and solved with the aid of the differential quadrature method (DQM). Afterward, a parametric study is done to present the effects of three kinds of FG patterns, weight fraction of the GPLs, radius ratio, and thickness to inner radius ratio on the bending characteristics of the FG-GPLRC disk. Numerical results reveal that in the initial value of the \(Zt/h\), using more GPLs for reinforcing the structure provides an increase in the normal stresses but this matter is inverse for the higher value of the \(Zt/h\). The results show that considering the smaller radius ratio is a reason for boosting the shear stresses of the structure for each \(Zt/h\). Another consequence is that for the negative value of \(Zt/h\), it is true that by increasing \(h/{R}_{i}\) , the normal stresses increases but if there is positive value for \(Zt/h\), the radial and circumferential stresses fall down by having an increase in the \(h/{R}_{i}\).

     

Subcellular effects and localization of binding sites of phytohemagglutinin in the potato leafhopper, Empoasca fabae (Insecta: Homoptera: Cicadellidae)

To identify the means by which phytohemagglutinin (PHA) exerts its toxicity on the potato leafhopper, four different methods (thick and semi-thin sectioning combined with immunofluorescent staining, in vitro receptor autoradiography, and immunoelectron microscopy) were used to elucidate the PHA target tissue, binding site, and its effects on this tissue. Sixteen 1- or 2-day-old female potato leafhoppers were fed for 36 h on each of three treatments: a control, diet or a diet containing either the PHA-E subunit or the PHA-L subunit. The PHA-E subunit, but not PHA-L, had previously been shown to be lethal. The insects were then prepared for both light and confocal microscopy. Analysis of images showed that PHA bound only to the surface of midgut epithelial cells of the potato leafhopper. PHA-E caused severe disruption, disorganization, and elongation of the brush border microvilli, and swelling of the epithelial cells into the lumen of the gut, leading to complete closure of the lumen. Furthermore, PHA-E stimulated the division of midgut epithelial cell nuclei, leading to two nuclei in each cell. Nuclei later elongated and degraded. In contrast, PHA-L had little effect on the epithelial cells of the midgut. It did not strongly bind to the surface of epithelial cells and caused much less disruption of brush-border microvilli, less disorganization of the cells and less elongation of nuclei. Strong binding of PHA occurred solely on the cell membrane of the brush border microvilli of epithelial cells. In contrast, the controls (i.e., midgut tissue, blocking agent, PHA, and antibodies) showed that midgut tissue was not autofluorescent and showed no fluorescent binding signal. Analysis of both bright- and dark-field images obtained by autoradiography and immunoelectron microscopy confirmed these findings.