Phase-Field Modeling of Eutectic Growth in a Ti-Fe System with Multiple Nuclei and Misorientations

In this article a phase-field model to investigate the formation of eutectic structures in a Ti-Fe alloy with high elastic misfit is introduced. Based on linear microelasticity theory, an elastic model is designed to incorporate the elastic energy into the phase-field formalism and later on adopted to growth of multiple nuclei with arbitrary orientations by including the orientation energy in phase-field ansatz. By using this model, we investigate the free growth of a limited number of eutectic nuclei and examine the influence of orientation free energies on elastic fields and the resulting microstructure.     

Evaluation of excitation function by TALYS code for producing ^109Cd with different ion beams

ion of millicurries of the radioisotope with incident beam energy less 15 MeV using low energy accelerator.     

Na2S-mediated thionation: an efficient access to secondary and tertiary α-ketothioamides via Willgerodt–Kindler reaction of readily available arylglyoxals with amines

The task of this paper is to provide an efficient process for synthesis of secondary and tertiary α-ketothioamides via Willgerodt–Kindler reaction of readily available arylglyoxals with amines using Na₂S as an effective catalyst. A plausible role for Na₂S in the reaction of arylglyoxals with primary amines is proposed.     

Micromorphology and Optical Bandgap Characterization of Copper Oxide Nanowires

Due to the industrial applications of nasno materials, the growth of Copper oxide (CuO) nanowires (NWs) at the same and opposite directions of the electric and gravitational fields was investigated to study the effects of fields on the NWs properties. The experiments were designed to grow NWs using thermal oxidation method at 450 ^°C for 50 h. NWs growth was evaluated to study two distinct cases; first, substrates exposed to the gravitational field and second those treated with electric field (EF) in-lined with gravitation field (GF). It was observed that the electric field developed a diameter homogeneity while compressing the NWs and decreasing the diameters. Furthermore, the GF influenced only the length of the NWs, while the EF had an impact on both length and diameter of the NWs. The direction of fields played an important role in NWs morphology and intensity of XRD pattern and optical properties. It was also observed that field direction greatly influenced the NWs length and diameter.     

Preparation of Zinc(II) Oxide Nanoparticles from a New Nano-Size Coordination Polymer Constructed from a Polypyridyl Amidic Ligand; Spectroscopic, Photoluminescence and Thermal Analysis Studies

A new zinc(II) coordination polymer, {[Zn(bpcdp)₂(DMF)₄](ClO₄)₂·(H₂O)₂}_n (1) bpcdp = 2,6-bis(4-pyridinecarboxamide)pyridine has been synthesized and characterized by IR, ¹HNMR and ¹³CNMR spectroscopy. The single crystal X-ray data of compound 1 shows the zinc(II) atom has been considered as octahedral with ZnN₂O₄ coordination sphere. Two nitrogen atoms of bpcdp ligand and four oxygen atoms of DMF molecules have occupied coordination sphere around zinc(II) atoms. The prepared zinc(II) coordination polymer grows in three-dimensional network by hydrogen bonding and π–π stacking interaction. The nanostructure of compound 1 were obtained by sonochemical process and studied by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), IR and NMR spectroscopy. Thermal stabilities of single crystalline and nano-size samples of compound 1 were studied by thermal gravimetric (TG) and differential thermal analyses (DTA). The ZnO nanoparticles were obtained by direct calcination of compound 1 at 400 °C and by thermolysis in oleic acid at 200 °C. The obtained zinc(II) oxide nanoparticles were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM).     

Performance Analysis of Time Reversal UWB Communication with Non-coherent Energy Detector

Non-coherent receivers, such as energy detectors (ED), are the simplest and the most practical alternatives to coherent receivers for low-rate and low-complexity applications in ultra-wideband (UWB) systems. However, these advantages are achieved at the expense of non-negligible performance degradation. One solution to improve the performance is to make use of time reversal (TR) technique. In this study, the performance of TR technique with non-coherent ED is analyzed in UWB systems. First, we derive an approximate analytical formula for the error probability of TR-ED which is based on tapped-delay line (TDL) channel model. Next, we theoretically and by simulations analyze the optimum integration interval which maximizes the performance of TR-ED. The results show that TR technique, by reducing the integration interval, considerably improves the performance compared to the conventional ED scheme.     

Precoder Design for BICM-MIMO Systems Under Channel Estimation Error

If properly designed, the use of a linear precoder can achieve the maximum coding gain and diversity order in bit-interleaved coded modulation with multiple-input multiple-output systems. However, such maximum coding gain and diversity order are compromised under the practical scenario of having imperfect channel state information (CSI) at the receiver. To alleviate the impact of imperfect CSI on the coding gain and diversity order, joint linear precoder and training pattern are designed in this paper. The design is carried out by considering both the pairwise error probability and the mean square error of the channel estimator. The effectiveness of the proposed design is illustrated by comparing its performance with the performance obtained when only the training pattern is designed for an precoder optimized under the perfect CSI. In particular, simulation results show that a $1.5$ 1.5 dB gain is achieved by the proposed design.     

Effects of Annealing on the Fabrication of Al-TiAl3 Nanocomposites Before and After Accumulative Roll Bonding and Evaluation of Strengthening Mechanisms

The strengthening mechanisms of Al-TiAl₃ nanocomposite, fabricated using cold roll bonding, annealing, and accumulative roll bonding (ARB) on Al sheets sandwiching with pure Ti powder were investigated in the present study. With annealing at 590 ℃ for 2 h, TiAl₃ intermetallic compound was formed. After subsequent ARB process up to 5 cycles, final composite consists of ultrafine Al grains of less than 500 nm with TiAl₃ particles larger than 200 nm. The strength and hardness of the final composite are 2.5 and 3.5 times the initial values, with an ultimate tensile strength of 400 MPa, which is dominated by grain-boundary strengthening due to the ultrafine Al grains, and Orowan strengthening due to the small TiAl₃ particles. For comparison, an alternative fabrication route of cold roll bonding-ARB-annealing was also studied. This study showed that annealing before ARB is a critical factor in producing an ultrafine grain structure containing TiAl₃ particles.     

Antioxidative and synergistic effects of bene kernel and hull oils during oxidation of virgin olive oil

Total amounts of conjugated diene hydroperoxides and carbonyl compounds of a virgin olive oil (VOO) and its purified form as affected by 0.1–6% w/w bene kernel (BKO) and hull (BHO) oils were monitored during 16 h heating at 180°C. The VOO was more prone to the production of off‐flavour carbonyl compounds than to the formation of conjugated diene hydroperoxides. The VOOs oxidative stability decreased significantly due to the removal of the indigenous antioxidative compounds. Oxidative stability, especially regarding the secondary oxidation, significantly improved with increasing concentrations of the BKO than with those of the BHO.