Atomistic non-equilibrium Green’s function simulations of Graphene nano-ribbons in the quantum hall regime

The quantum Hall effect in Graphene nano-ribbons (GNR) is investigated with the non-equilibrium Green’s function (NEGF) based quantum transport model in the ballistic regime. The nearest neighbor tight-binding model based on p _z orbital constructs the device Hamiltonian. GNRs of different edge geometries (Zigzag and Armchair) are considered. The magnetic field is included in both the channels and contact through Peierls substitution. Efficient algorithms for calculating the surface Green function are used to reduce computation time to enable simulating realistically large dimensions comparable to those used in experiments. Hall resistance calculations exactly reproduce the quantum Hall plateaus observed in the experiments. Use of large dimensions in the simulation is crucial in order to capture the quantum Hall effect within experimentally magnetic fields relevant 10–20 T. R. Golizadeh-Mojarad and A.N.M. Zainuddin contributed equally to this work.     

Investigation of magnetic and ferroelectric properties along with the magnetoelectric coupling behavior for asserting a room temperature bi-phase composite as multiferroics

Various composites of nominal composition (1-x)Ba_0.95Ca_0.05TiO₃?+?xLi_0.1Cu_0.1Co_0.1Zn_0.6Fe_2.1O₄ have been prepared and studied thoroughly. X-ray diffraction and Rietveld refinement confirmed the presence of Ba_0.95Ca_0.05TiO₃ and Li_0.1Cu_0.1Co_0.1Zn_0.6Fe_2.1O₄ phases in the composites. The microstructures have been investigated by field emission scanning electron microscopy. Temperature dependent dielectric constant shows two peaks, one is at 150 °C and another at 270 °C for x?=?0.10 composite which resembles the characteristic ferroelectric and ferromagnetic transition peaks. A gradual progression of ferro-para electric transition towards room temperature is observed with doping. The non-Debye type dipole relaxations have been found. The linearity in the log(σ_AC) vs. log(ω) plots indicate that conduction is due to small polaron hopping. The real part of initial permeability increases with growing ferrite concentration but the cut-off frequency decreases. The magnetic property is also enhanced with doping content. The typical ferroelectric hysteresis loops have also seen with the addition of Li_0.1Cu_0.1Co_0.1Zn_0.6Fe_2.1O₄ up to x?=?0.40. The impedance values are found to decreases in the Nyquist plots. The magnetoelectric voltage coefficient is obtained 287?×?10³ V/mT for x?=?0.15 at room temprrature. We found both ferromagnetic and ferroelectric hysteresis loops at room temperature. So, it confirms that the composites exhibit room temperature multiferroicity. This type of composites offers variety of opportunity for multifunctional devices application like hetero-structured read / write memory devices, switching devices and magnetic field sensing devices.

     

Resources-aware trusted node selection for content distribution in mobile ad hoc networks

We propose a novel trust and probabilistic node selection mechanism for content distribution in mobile ad hoc networks. Due to the open nature of such networks which as a rule do not have strict node membership control, the selection of trustworthy nodes is an important challenge, especially as the resources (e.g., battery, bandwidth) of the mobile devices are limited and should not be wasted on erroneous or malicious content. Our proposal, in addition to considering the trustworthiness of nodes, ensures that the traffic load is equally shared amongst the population of nodes, thus further conserving mobile node resources. We analyse the proposed mechanisms and evaluate it against selected previously proposed trust schemes which, in the majority, favour the selection of the most trustworthy node. We demonstrate the benefits of our proposal which provides load balancing and prevents overuse of a single node’s resources, while still providing a good performance in regards to accurately choosing trustworthy nodes to provide the required content.     

Physico-Mechanical and Degradation Properties of Gamma-Irradiated Biocomposites of Jute Fabric-Reinforced Poly(caprolactone)

Jute fabric-reinforced poly(caprolactone) biocomposites (30–70% jute) were fabricated by compression molding. Tensile strength, tensile modulus, bending strength, bending modulus and impact strength of the non-irradiated composites (50% jute) were found to be 65 MPa, 0.75 GPa, 75 MPa, 4.2 GPa and 6.8 kJ/m², respectively. The composites were irradiated with gamma radiation at different doses (50–1000 krad) at a dose rate of 232 krad/hr and mechanical properties were investigated. The irradiated composites containing 50% jute showed improved physico-mechanical properties. The degradation properties of the composites were observed. The morphology was evaluated by scanning electron microscope.     

Ayka,a Novel Curtobacterium Bacteriophage,Provides Protection against Soybean Bacterial Wilt and Tan Spot

Diseases caused by the Gram-positive bacterium Curtobacterium flaccumfaciens pv. flaccumfaciens (Cff) inflict substantial economic losses in soybean cultivation. Use of specific bacterial viruses (bacteriophages) for treatment of seeds and plants to prevent the development of bacterial infections is a promising approach for bioprotection in agriculture. Phage control has been successfully tested for a number of staple crops. However, this approach has never been applied to treat bacterial diseases of legumes caused by Cff, and no specific bacteriophages have been known to date. This paper presents detailed characteristics of the first lytic bacteriophage infecting this pathogen. Phage Ayka, related to φ29-like (Salasmaviridae) viruses, but representing a new subfamily, was shown to control the development of bacterial wilt and tan spot in vitro and in greenhouse plants.     

The Use of DArTseq Technology to Identify Markers Linked to Genes Responsible for Seed Germination and Seed Vigor in Maize

Seed vigor and seed germination are very important traits, determined by several factors including genetic and physical purity, mechanical damage, and physiological condition, characterized by maintaining a high seed vigor and stable content after storage. The search for molecular markers related to improvement in seed vigor under adverse condition is an important issue in maize breeding currently. Higher sowing quality of seeds is necessary for the development of the agriculture production and better ability to resist all kinds of adversity in the seeds’ storage. Condition is a very important factor affecting the yield of plants, thanks to the construction of their vitality. Identification of molecular markers associated with seed germination and seed vigor may prove to be very important in the selection of high-yielding maize varieties. The aim of this study was to identify and select new markers for maize (SNP and SilicoDArT) linked to genes influencing the seed germination and seed vigor in inbred lines of maize (Zea mays L.). The plant material used for the research was 152 inbred maize lines. The seed germination and seed vigor were analyzed. For identification of SNP and SilicoDArT markers related to the seed germination and seed vigor, the SilicoDarT technique developed by Diversity Arrays Technology was used. The analysis of variance indicated a statistically significant differentiation between genotypes for both observed traits. Positive (r = 0.41) correlation (p < 0.001) between seed germination and seed vigor was observed. As a result of next-generation sequencing, the molecular markers SilicoDArT (53,031) and SNP (28,571) were obtained. Out of 81,602 identified SilicoDArT and SNP markers, 15,409 (1559 SilicoDArT and 13,850 SNP) were selected as a result of association mapping, which showed them to be significantly related to the analyzed traits. The 890 molecular markers were associated with seed vigor, and 1323 with seed germination. Fifty-six markers (47 SilicoDArT and nine SNP) were significant for both traits. Of these 56 markers, the 20 most significant were selected (five of these markers were significant at the level of 0.001 for seed vigor and at the level of 0.05 for seed germination, another five markers were significant at the level of 0.001 for seed germination and at the level of 0.05 for seed vigor, five markers significant at the level of 0.001 only for seed vigor and five significant at the level of 0.001 only for seed germination also selected). These markers were used for physical mapping to determine their location on the genetic map. Finally, it was found that six of these markers (five silicoDArT—2,435,784, 4,772,587, 4,776,334, 2,507,310, 25,981,291, and one SNP—2,386,217) are located inside genes, the action of which may affect both seed germination and seed vigor. These markers can be used to select genotypes with high vigor and good seed germination.     

Mechanical properties of polypropylene composites reinforced with chemically treated abaca

In the present study, abaca was chemically treated with benzene diazonium salt in order to improve in the mechanical properties of the abaca-PP composites. Both raw and treated abaca samples were utilized for the fabrication of the composites. The mechanical properties of the composites prepared from chemically treated abaca are found to increase substantially compared to those of untreated ones. Tensile strengths of the composites of both raw and chemically treated abaca-PP composites showed a decreasing trend with increasing filler content. However, the values for the chemically treated abaca-PP composites at all mixing ratios are found to be higher than that of neat PP. The surface morphologies of the fracture surfaces of the composites were recorded using scanning electron microscopy (SEM). The SEM micrographs reveal that interfacial bonding between the treated filler and the matrix has significantly improved, suggesting that better dispersion of the filler into the matrix has occurred upon treatment of abaca.