A comparative study on structural,morphological and photocatalytic properties of anodically grown ZnO nanowires under varying parameters

Journal of Materials Science: Materials in Electronics - In this study, zinc oxide (ZnO) nanowires (NWs) were successfully produced on Zn plates through electrochemical anodization in potassium...     

Investigation of combustion and emission characteristics in a TBC diesel engine fuelled with CH4–CO2–H2 mixtures

In this study, an experimental investigation was performed to reveal combustion and emission characteristics of common-rail four-cylinder diesel engine run with CH₄, CO₂ and H₂ mixtures. The engine pistons were thermally coated with zirconia and Ni–Al bond coat by plasma spray method. With a small amount of the pilot diesel, port fuelled methane (100% CH₄), synthetic biogas (80% CH₄ + 20% CO₂), and hydrogen presented (80% CH₄+10% CO₂+10% H₂) mixtures were used as main fuel at different loads (50 Nm, 75 Nm, and 100 Nm) at a constant speed of 1750 min^?1. Comparative analysis of the combustion (cylinder pressure, PRR, HRR, CHR, ringing intensity, CA10, CA50, and CA90), BSFC, and emissions (CO₂, HC, NO_x, smoke, and oxygen) at the various engine loads with and without piston coating was made for all fuel combinations. It was found that coating the engine pistons enhanced the examining combustion characteristics, whereas it slightly changed BSFC and most of the emissions. As compared to the sole diesel fuel, the gaseous fuel operations showed higher in-cylinder pressure, PRR, and ringing intensity values, earlier combustion starting and CAs, and lower diesel injection pressure at the same engine operating conditions. Dramatic increase in the ringing intensity was particularly found by the hydrogen introduced mixture under the tests with coated piston. HC and CO₂ emissions increased in operation with the synthetic biogas; however, hydrogen introduction reduced HC emissions by 4.97–30.92%, and CO₂ emissions by 5.16–10%.     

Overview of Compaction Data Analysis Techniques

In this review article, the techniques that have been utilized to assess the compactional behaviour of pharmaceutical materials were presented, and the advantages, limitations and modifications of some of these methods were discussed. It was concluded that despite some of these techniques, such as Heckel equation, F-D curves, energy of compaction, tensile strength and hardness measurements, have received considerable attention, none of them was found to be satisfactory for the comprehensive analysis of the mechanisms involved in the compaction of the solid particulate matter.     

Formulation and Compaction of Microspheres

The factors affecting the tabletability of formulations containing uncoated and/or coated microspheres were discussed by presenting a case study. The size and shape, as well as surface properties of microspherical particles, the type and amount of coating agent, selection of the external additives, and the rate and magnitude of the pressure applied were found to be the most critical factors to be considered in order to obtain and maintain the desired drug release properties of the microspheres. It was found that microcrystalline cellulose was needed in order to produce satisfactory beads in terms of size, shape and surface characteristics. The microsphere formulations, which were found to be highly sensitive to lubrication, were more compressible than their powder forms, but produced much weaker tablets. When coated with Surelease, increasing the amount of coating on the pellets reduced the tensile strength of their compacts. Compaction of the microspheres at high velocities resulted in a decrease in the tensile strength values and an increase in the volumetric strain recovery values. Dissoultion studies revealed that, regardless of the amount of coating applied, the coated microspheres lost their sustained release properties during compaction.     

A new feature extraction approach based on one dimensional gray level co-occurrence matrices for bearing fault classification

ABSTRACT

Recently, precise and deterministic feature extraction is one of the current research topics for bearing fault diagnosis. For this aim, an experimental bearing test setup was created in this study. In this setup, vibration signals were obtained from the bearings on which artificial faults were generated in specific sizes. A new feature extraction method based on co-occurrence matrices for bearing vibration signals was proposed instead of the conventional feature extraction methods, as in the literature. The One (1) Dimensional–Local Binary Patterns (1D-LBP) method was first applied to bearing vibration signals, and a new signal whose values ranged between 0–255 was obtained. Then, co-occurrence matrices were obtained from these signals. The correlation, energy, homogeneity, and contrast features were extracted from these matrices. Different machine learning methods were employed with these features to carry out the classification process. Three different data sets were used to test the proposed approach. As a result of analysing the signals with the proposed model, the success rate is 87.50% for dataset1 (different speed), 96.5% for dataset2 (fault size (mm)) and 99.30% for dataset3 (fault type – inner ring, outer ring, ball) was found, respectively.     

A systematic design of 1.5–9 GHz high power–high efficiency two‐stage GaAs PHEMT power amplifier

In this article, a systematic design approach for a Class‐A operated wideband power amplifier is presented. The power amplifier structure comprises of two transistors in the cascaded single stage traveling wave amplifier topology. A power amplifier was designed by using the systematic approach and fabricated with 0.25 μm GaAs PHEMT MMIC process. The amplifier has an area of 3.4 × 1.4 mm². Measurement results show that almost flat gain performance is obtained around 15 dB over 1.5–9 GHz operating bandwidth. In most of the band, with the help of a wideband load‐pull matching technique, the amplifier delivers P_o,sat and P_o,1dB of around 30 dBm and 28 dBm where the corresponding power added efficiencies are >50% and >36%, respectively. It is shown that the proposed design approach has the advantage of simple and systematic design flow and it helps to realize step‐by‐step design for the designers. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:615–622, 2014.     

A Catadioptric and Pan-Tilt-Zoom Camera Pair Object Tracking System for UAVs

Unmanned aerial vehicles (UAVs) are seeing widespread use in military, scientific, and civilian sectors in recent years. As the mission demands increase, these systems are becoming more complicated. Omnidirectional camera is a vision sensor that can captures 360° view in a single frame. In recent years omnidirectional camera usage has experienced a remarkable increase in many fields, where many innovative research has been done. Although, it is very promising, employment of omnidirectional cameras in UAVs is quite new. In this paper, an innovative sensory system is proposed, that has an omnidirectional imaging device and a pan tilt zoom (PTZ) camera. Such a system combines the advantages of both of the camera systems. The system can track any moving object within its 360° field of view and provide detailed images of it. The detection of the moving object has been accomplished by an adaptive background subtraction method implemented on the lowered resolution images of the catadioptric camera. A novel algorithm has also been developed to estimate the relative distance of the object with respect to the UAV, using tracking information of both of the cameras. The algorithms are implemented on an experimental system to validate the approach.     

Coating of modified poly(ethylene terephthalate) fibers with sericin-capped silver nanoparticles for antimicrobial application

Polymer Bulletin - In this work, a kind of amine-type PET fibers was synthesized by reacting hexamethylenediamine (HMDA) with methacrylic acid-g-poly(ethylene terephthalate) (PET-g-MAA) fibers for...     

Enhanced catalytic activity of monodispersed AgPd alloy nanoparticles assembled on mesoporous graphitic carbon nitride for the hydrolytic dehydrogenation of ammonia borane under sunlight

We address the composition-controlled synthesis of monodispersed AgPd alloy nanoparticles (NPs),their assembly for the first time on mesoporous graphitic carbon nitride (mpg-C3N4),and the unprecedented catalysis of mpg-C3N4@AgPd in the hydrolytic dehydrogenation of ammonia borane (AB) at room temperature.Monodispersed AgPd alloy NPs were synthesized using a high-temperature organic-phase surfactant-assisted protocol comprising the co-reduction of silver(Ⅰ) acetate and palladium(Ⅱ) acetylacetonate in the presence of oleylamine,oleic acid,and 1-octadecene.This protocol allowed the synthesis of four different compositions of AgPd alloy NPs.The AgPd alloy NPs were then assembled on mpg-C3N4,reduced graphene oxide,and Ketjenblack using a liquid-phase self-assembly method.Among the three supports tested,the mpg-C3N4@AgPd catalysts provided the best activity because of the Mott-Schottky effect,which was driven by the favorable work function difference between mpg-C3N4 and the metal NPs.Moreover,the activity of the mpg-C3N4@AgPd catalyst was further enhanced by an acetic acid treatment (AAt),and a record initial turnover frequency of 94.1 mol(hydrogen)·mol(catalyst)-1·min-1 was obtained.Furthermore,the mpg-C3N4@Ag42Pd58-AAt catalyst also showed moderate durability for the hydrolysis of AB.This study also includes a wealth of kinetic data for the mpg-C3N4@AgPd-catalyzed hydrolysis of AB.