Influence of deposition potential on the electrodeposited Ternary CoFeCu films

Ternary CoFeCu films, relating their magnetic and magnetoresistance properties with film composition, surface morphology and the corresponding crystal structure, were investigated in terms of different deposition potentials in electrodeposition. The films were grown on polycrystalline titanium substrates. The potentials were obtained from cyclic voltammetry and the current–time transients were also recorded to control the growth of proper films. From the structural analysis by X-ray diffraction, all films had a face-centred cubic structure and the calculated grain size increased with increasing deposition potential. The film compositions by energy dispersive X-ray spectroscopy revealed that the Co, Fe and Cu contents varied and the scanning electron microscope images disclosed that the film morphologies changed as the deposition potential changed. The saturation magnetization was high and coercivity was low at high deposition potential. The easy axis of magnetization was parallel to the film plane for all films. All films showed anisotropic magnetic resistance and their magnitudes were between 3.2 and 3.8 %. The variations in magnetic and magnetoresistive properties related to the microstructure were attributed to the variation of the film contents caused by deposition potential.     

Development of the structure of an imitation cheese with low protein content

The structure of an imitation cheese with low protein content was developed by replacing 80% of the rennet casein with waxy maize starch and κ-carrageenan in the formula. Starch was partially hydrolyzed by using a fungal α-amylase to provide meltability. Formulation studies were carried out to obtain meltability and textural properties of a hard cheese with high protein content in the developed cheese. Response surface method was used to determine the effects of α-amylase and κ-carrageenan on the physical properties of the cheese. Hardness, cohesiveness and springiness of the cheese were affected positively by κ-carrageenan and negatively by α-amylase. Square of the meltability scores was used to explain the effects of components on meltability of the cheese. Square of the meltability was affected positively by α-amylase and negatively by κ-carrageenan. A formula was determined by using multiple response optimization method that would provide hardness, cohesiveness and meltability in the developed cheese similar to those of the high protein counterpart used as targets. Results obtained from a trial cheese produced according to the determined formula confirmed that the values of physical properties estimated by the optimization can be achieved.     

Properties of Iron Oxide Nanoparticles Synthesized at?Different?Temperatures

Iron oxide nanoparticles were synthesized by co-precipitation in air atmosphere at different temperatures and their structural and magnetic properties were investigated. The mean particle sizes of iron oxide nanoparticles were calculated from the X-ray diffraction (XRD) patterns using the Scherrer equation. Fourier transform infrared spectroscopy analysis exhibited the vibration bands at 563 cm^?1 and 620 cm^?1 confirming the formation of Fe₃O₄ and ??-Fe₂O₃, respectively. Morphological observation was made by a transmission electron microscope and the particle size of iron oxide nanoparticles was found to be around 9 nm which is consistent with the particle size calculated according to the XRD patterns. It was observed that the intensity of the peaks in the patterns and crystallinity increased as the temperature increased. Magnetization curves showed zero coercivities indicating that the samples are superparamagnetic.     

Superparamagnetic iron oxide nanoparticles: effect of iron oleate precursors obtained with a simple way

The objective of the study was to investigate the effect of different amounts of iron oleate precursor with different oleic acid amounts on the properties of the synthesised nanoparticles by thermal decomposition. The iron oleate precursors which formed from oleic acids in the order of 0.5, 1.0, 1.5 and 2.0 g, and 0.1 g iron powder was prepared under 200 °C seperately, using a facile solvothermal method under study. Thermal analysis of iron oleat precursors by a thermogravimetric analysis (TGA) revealed that the different amount of oleic acid was seen to have an impact on the thermal properties of iron oleat complexes. During the synthesis of nanoparticles, iron oleate complex in 1-hexadecane kept refluxing for 3 h under air atmosphere resulting in the formation of nanoparticles. The fourier transform infrared spectra measurements and the TGA analysis disclosed that nanoparticles were coated with oleic acid. To the X-ray diffraction patterns, all samples are iron oxide nanocrystals and their crystal sizes increased from 6.4 to 9.8 nm with decreasing oleic acid. Also, the sizes of nanoparticles were found to be in same range as confirmed with the surface observation by a transmission electron microscope. The magnetic properties obtained from a vibrating sample magnetometer revealed that all nanoparticles are superparamagnetic at room temperature. Also, their saturation magnetizations were up to 33.2 emu/g. It is seen that the nanoparticles are superparamagnetic with the desired structural and corresponding magnetic properties and therefore, they could be thought to be convenient for biomedical applications as the particles can be transferred to aqueous phase.     

Alkaline phosphatase biosensors based on layered double hydroxides matrices: Role of LDH composition

Alkaline phosphatase (AlP) biosensors were developed based on the immobilization of this enzyme by adsorption or coprecipitation methods in different layered double hydroxides (LDH) matrices: Zn₂Al–Cl and Mg₂Al–CO₃. Several characteristics of the AlP/LDH membranes, such as the enzyme immobilization procedure, permeability, buffering effect were investigated. It appeared that the basic nature of the MgAl–LDH nanomaterial improved the stability of the immobilized AlP regarding pH. The synergy between the LDH immobilization matrix and the use of hydroquinone diphosphate (HQDP) as substrate provided a very fast and stable response for the AlP/MgAl–LDH biosensors at 0.4 V.     

Epidemic-based reliable and adaptive multicast for mobile ad hoc networks

An emerging approach to distributed systems exploits the self-organization, autonomy and robustness of biological epidemics. In this article, we propose a novel bio-inspired protocol: EraMobile (Epidemic-based Reliable and Adaptive Multicast for Mobile ad hoc networks). We also present extensive performance analysis results for it. EraMobile supports group applications that require high reliability. The protocol aims to deliver multicast data reliably with minimal network overhead, even under adverse network conditions. With an epidemic-based multicast method, it copes with dynamic and unpredictable topology changes due to mobility. Our epidemic mechanism does not require maintaining any tree- or mesh-like structure for multicasting. It requires neither a global nor a partial view of the network, nor does it require information about neighboring nodes and group members. In addition, it substantially lowers overhead by eliminating redundant data transmissions. Another distinguishing feature is its ability to adapt to varying node densities. This lets it deliver data reliably in both sparse networks (where network connectivity is prone to interruptions) and dense networks (where congestion is likely). We describe the working principles of the protocol and study its performance through comparative and extensive simulations in the ns-2 network simulator.     

Effects of using different boundary conditions and computational domain dimensions on modeling and simulations of periodic metamaterial arrays in microwave frequencies

This article aims to demonstrate the effects of using different boundary conditions and different computational volume dimensions in numerical simulations of periodic metamaterial arrays. A double band metamaterial unit cell design will be utilized to show that use of different boundary conditions may result in simulation of dissimilar periodic array topologies with completely different electromagnetic responses. It will also be shown that dimensions of the computational volume may strongly affect the overall response of the metamaterial structure due to varying electromagnetic coupling between the array elements. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2013.     

Reduction and characterizations of iron particles: influence of reduction parameters

Iron particles have some applications as electromagnetic devices in magnetic recording and data storage technology due to their small sizes and high data storage capacity. The devices can be advanced by improving the properties of existing materials according to the production parameters. Thus, the influences of reduction parameters on the properties of iron particles were studied. The iron particles were reduced from superparamagnetic iron oxide nanoparticles by altering reduction parameters under hydrogen atmosphere at high (400 °C) temperature. The structural analysis of the films was carried out using the X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM) techniques. The XRD data revealed that the crystal textures changed for the particles reduced at each parameter. And, the crystal structure turns from the cubic spinel structure of magnetite and body centered cubic (bcc) structure of iron to the bcc iron as the reduction time increases from 15 to 240 min. Then, the similar structure change can be seen for the samples reduced at increasing hydrogen flow rates. The HRTEM studies revealed that the surface morphology of the films strongly depend on the flow rate. Finally, magnetite peaks weaken and then disappear as the precursor mass decreases to the lowest value. The average crystallite sizes were found to be consistent with changing crystal structure. Furthermore, the magnetic characteristics studied by a vibrating sample magnetometer were observed to be affected by the parameters. Besides, magnetic differences may arise from the variation of crystal structure and crystal sizes caused by individual reduction parameters of reduction time, hydrogen flow rate and precursor mass.