Potential of earthing grid in heterogeneous soil

Calculation of the scalar electric potential of an earthing grid in heterogeneous soil is obtained by the finite element technique combining differential and integral formulations of the problem. Such a combined formulation made it possible to generate easily the mesh of finite elements and to divide the problem domain into a sufficiently small number of large finite elements. The unbounded domain of calculation is solved by using mapped infinite elements. The contribution of singular sources is represented by the analytical expression, and included in the approximation function of the potential. A sufficiently satisfactory approximation is realized with a small number of singular source images, obtained by local imaging of sources within a finite element on its boundary surfaces. The calculation accuracy is tested on examples solvable by an average potential method which is based on an integral formulation of the problem.     

Synthesis and Investigation of Electrodeposited Half-Metallic Fe3O4 Thin Films and Nanowires

Thin films and nanowires of Fe₃O₄ have potentiostatically been electrodeposited on ITO coated glass and employing templates in a conventional three-electrode cell using two different baths. Appropriate potential windows, suitable for films and nanowires, were estimated from cyclic voltametry. Structural property of Fe₃O₄ films was studied by X-ray diffraction. A large (?3.35%, at 2.3 kOe) longitudinal magnetoresistance (MR) was observed at room temperature, and the shape of MR curves showed a reduced hysteresis loop for Fe₃O₄ films with low coercivity. Room-temperature magnetic properties of Fe₃O₄ films were studied by vibrating sample magnetometer (VSM). Surface morphology of nanowires was studied by scanning electron microscope (SEM). The nonlinear I?CV characteristic of nanowires was observed at room temperature. An attempt has been made to understand the conduction mechanism.     

Grapevine Leafroll-Associated Virus 3 in Single and Mixed Infections Triggers Changes in the Oxidative Balance of Four Grapevine Varieties

With the aim to characterize changes caused by grapevine leafroll-associated virus 3 (GLRaV-3) singly or in coinfection with other viruses and to potentially determine genotype-specific or common markers of viral infection, thirty-six parameters, including nutrient status, oxidative stress parameters, and primary metabolism as well as symptoms incidence were investigated in ‘Cabernet Franc,’ ‘Merlot,’ ‘Pinot Noir,’ and ‘Tribidrag’ grapevine varieties. Host responses were characterized by changes in cellular redox state rather than disturbances in nutrient status and primary metabolic processes. Superoxide dismutase, hydrogen peroxide, and proteins were drastically affected regardless of the type of isolate, the host, and the duration of the infection, so they present cellular markers of viral infection. No clear biological pattern could be ascertained for each of the GLRaV-3 genotypes. There is a need to provide a greater understanding of virus epidemiology in viticulture due to the increasing natural disasters and climate change to provide for global food production security. Finding grape varieties that will be able to cope with those changes can aid in this task. Among the studied grapevine varieties, autochthonous ‘Tribidrag’ seems to be more tolerant to symptoms development despite numerous physiological changes caused by viruses.     

Denoising Medical Images Using Deep Learning in IoT Environment

Medical Resonance Imaging (MRI) is a noninvasive, nonradioactive, and meticulous diagnostic modality capability in the field of medical imaging. However, the efficiency of MR image reconstruction is affected by its bulky image sets and slow process implementation. Therefore, to obtain a high-quality reconstructed image we presented a sparse aware noise removal technique that uses convolution neural network (SANR_CNN) for eliminating noise and improving the MR image reconstruction quality. The proposed noise removal or denoising technique adopts a fast CNN architecture that aids in training larger datasets with improved quality, and SARN algorithm is used for building a dictionary learning technique for denoising large image datasets. The proposed SANR_CNN model also preserves the details and edges in the image during reconstruction. An experiment was conducted to analyze the performance of SANR_CNN in a few existing models in regard with peak signal-to-noise ratio (PSNR), structural similarity index (SSIM), and mean squared error (MSE). The proposed SANR_CNN model achieved higher PSNR, SSIM, and MSE efficiency than the other noise removal techniques. The proposed architecture also provides transmission of these denoised medical images through secured IoT architecture.     

Wind turbine overspeed protection based on polytopic robustly invariant sets

Complex mechanical systems, such as wind turbines, often include safety constraints which should not be violated in order to avoid high risk of structural damage. Adherence to the safety constraints is ensured with a well‐designed operating envelope protection. In this paper, we present an invariant set‐based protection concept with the application to the wind turbine overspeed protection. The approach is model‐based and operates without wind‐preview measurements. Instead, it is based on the evolution model of the wind disturbance in the worst‐case scenario manner. Accurate system estimation utilizing the blade root in‐plane measurement is proposed, along with the efficient algorithm for the hard real‐time operation of the protection system. The overspeed protection system is validated in extensive simulations on extreme turbulent wind, performed in GH Bladed. The results show the effectiveness of the proposed concept compared with the baseline controller performance. Copyright © 2015 John Wiley & Sons, Ltd.     

PERFORMANCE EVALUATION OF A CONVENTIONAL NAUTAMIXER APPLIED AS A DIRECT DRYER

This paper describes the experiments which were conducted with the objective to determine the potential of a conventional Nautamixer applied as a direct dryer. This convective Nautamixer-dryer was used for drying the urea nitrate containing around 15% of water, which is converted from a pasteous form into a powder of a moisture lewel below 1%.

The influence of the following variables was studied: increased hot air velocity and temperature, number of revolutions of the agitator, and mass of the drying material. The effect of inlet air distribution to the periphery of the bed of the material was studied with a perforated plate distributor by blanking the holes (17%). which adversely affected the drying rate. The examination of the effect of external heating through the wall indicated that it is not possible to achieve the desired moisture level of the product without the introducing the flowing hot air. As an addition to the convective drying the indirect drying contributed more to the increase of the outlet air temperature than to the increase of the drying rate. As expected, shorter drying time is obtained with higher air flow rates and temperatures as well as with increased number of revolutions of both the orbital arm and the mixing screw.     

Cobalt substituted ZnO thin films: a potential candidate for spintronics

Cobalt doped zinc oxide thin films have been deposited using spray pyrolysis method. These single phasic films exhibited [100] preferential texture and small decrease in the lattice parameter on cobalt substitution. The films having different Co concentration have almost similar surface morphology and microstructure. These Zn_1?x Co _x O (x ≤ 0.10) thin films distinctly showed ferromagnetic character at room temperature. The optical transmission measurements of these films clearly proved that in these films Co substitutes for Zn²⁺ and exists in +2 state. Based on the optical, structural and magnetic measurements, the possibility of occurrence of ferromagnetic ordering due to cobalt clustering is ruled out in these spray-pyrolyzed films. A correlation of the observed ferromagnetic behavior in these Zn_1?x Co _x O films with structural change resulting from the addition of Co is presented in this paper.     

Rigorous formulation for electromagnetic plane-wave scattering from a general-shaped groove in a perfectly conducting plane

Scattering of an obliquely incident plane wave by a general-shaped groove engraved on a perfectly conducting plane is rigorously solved. The scattered field is represented by a Fourier-integral representation. To analytically represent the fields in a general-shaped groove, the groove is divided into L number of layers. Fields are then expressed in each layer as summations of 2D spatial harmonic fields with unknown coefficients. Matching the boundary conditions between layers provides a linear set of equations connecting all the unknown harmonic coefficients. Judicious use of Fourier transform on the equations resulting from matching boundary conditions at the groove aperture provides a series representation of the scattered field in the spectral domain with unknown harmonic coefficients of the first layer in the groove. A stable solution is obtained by solving the complete system of equations with an adaptive choice for the number of modes in each layer.     

PERFORMANCE EVALUATION OF A CONVENTIONAL NAUTAMIXER APPLIED AS A DIRECT DRYER

This paper describes the experiments which were conducted with the objective to determine the potential of a conventional Nautamixer applied as a direct dryer. This convective Nautamixer-dryer was used for drying the urea nitrate containing around 15% of water, which is converted from a pasteous form into a powder of a moisture lewel below 1%.

The influence of the following variables was studied: increased hot air velocity and temperature, number of revolutions of the agitator, and mass of the drying material. The effect of inlet air distribution to the periphery of the bed of the material was studied with a perforated plate distributor by blanking the holes (17%). which adversely affected the drying rate. The examination of the effect of external heating through the wall indicated that it is not possible to achieve the desired moisture level of the product without the introducing the flowing hot air. As an addition to the convective drying the indirect drying contributed more to the increase of the outlet air temperature than to the increase of the drying rate. As expected, shorter drying time is obtained with higher air flow rates and temperatures as well as with increased number of revolutions of both the orbital arm and the mixing screw.