An electrochemomechanical polishing process using magnetorheological fluid

A new electrochemomechanical polishing process using a magnetorheological (MR) fluid is proposed in this study. The process uses the electrochemical anodic reactions on an electrically conductive workpiece under an electric field and an electrolytic solution soaked in the same carbonyl iron (CI) particles as those used in the conventional MR polishing process, where the yield stress is controllable through the external magnetic field. Through experiments, we show that the new process is suitable for polishing three-dimensionally configured workpieces made of very hard materials, such as glassy carbon (GC), that are very difficult to polish using conventional processes.To examine the benefits and limitations of the proposed polishing process, a preliminary electrochemical experiment was performed on GC specimens, and the characteristics of the resultant electrochemical reactions in an aqueous electrolytic solution were investigated. The effectiveness of the proposed process was then demonstrated by polishing GC molds designed to replicate a glass channel-mixer structure used for biochemical inspection applications.     

Surface Selective Oxide Reduction During the Intercritical Annealing of Medium Mn Steel

Third generation advanced high-strength steels achieve an excellent strength–ductility balance using a cost-effective alloy composition. During the continuous annealing of medium Mn steel, the formation of an external selective oxide layer of MnO has a negative impact on the coating quality after galvanizing. A procedure to reduce the selective oxide was therefore developed. It involves annealing in the temperature range of 1073 K to 1323 K (800 °C to 1050 °C) in a HN_x gas atmosphere. Annealing at higher temperatures and the use of larger H₂ volume fractions are shown to make the gas atmosphere reducing with respect to MnO. The reduction of the surface MnO layer was observed by SEM, GDOES, and cross-sectional TEM analysis.     

Effects of Gamma Irradiation on the Chemical Composition and Antioxidant Activity of Lactarius deliciosus L. Wild Edible Mushroom

The short shelf-life of mushrooms is an obstacle to the distribution and marketing of the fresh product. There has been extensive research on finding the most appropriate technology for mushrooms preservation and a particular interest arises for wild species. Treatment by irradiation emerges as a possible conservation technique that has been tested successfully in several food products. Herein, the effects of gamma irradiation on Lactarius deliciosus (L. ex Fr.) S. F. Gray chemical composition and antioxidant activity were evaluated in samples submitted to different storage periods (0, 4 and 8 days) at 4 °C. The irradiation treatments were performed in a Co-60 experimental equipment. Nutritional value was accessed by macronutrients analysis and determination of energetic value; fatty acid, sugar and tocopherol profiles were determined by gas chromatography–flame ionization detector, high-performance liquid chromatography (HPLC) refractive index and HPLC fluorescence, respectively. The antioxidant activity was evaluated through radical scavenging activity, reducing power, lipid peroxidation inhibition and phenolics content. The obtained data show that, until 1 kGy, gamma irradiation might provide a useful alternative to ensure the quality and extend the life of mushrooms, since its effects on macronutrients, energetic value, tocopherols and antioxidant activity EC₅₀ values were less significant than the changes caused by storage time. Moreover, the chemical and nutritional composition was similar in irradiated and non-irradiated L. deliciosus samples.     

Effect of Poly(4-vinylphenol) Concentration Increase on Deposition Rate of Dielectric Thin Film Fabrication by Using Electrohydrodynamic Atomization

In this work, the effect of poly(4-vinylphenol) (PVP) concentration increase on electrohydrodynamic atomization and its deposition rate has been studied. The aim of this study is to further increase the deposition rate of uniform dielectric thin films by the nonvacuum electrohydrodynamic atomization process. The operating envelope has been explored by subjecting ink to controlled flow through a metallic capillary exposed to an electric field at ambient temperature. It has been observed that greater applied voltage is required to develop a stable cone jet from a highly concentrated PVP meniscus, in comparison with lower concentration. A combination of optimized parameters has been used from the developed operating envelope to generate an electrohydrodynamic jet, which subsequently disintegrated into droplets, thus depositing a uniform PVP thin film on indium tin oxide-coated polyethylene terephthalate substrates with average thickness of ~40 nm at constant substrate speed of 3 mm/s. The PVP thin film has been characterized by using scanning electron microscopy, x-ray photoelectron spectroscopy, and ultraviolet (UV)–visible spectroscopy.     

Anti‐urban ideologies and planning in France and Switzerland: Jean‐François Gravier and Armin Meili

Jean‐François Gravier and Armin Meili were two leading pioneers of planning in France and Switzerland. Gravier was the famous author of Paris et le désert français, first published in 1947; Meili was the author of the first national conception of planning in Switzerland and was very active in planning policy in the 1940s. Each has deeply influenced the implementation of planning policy in his country and both have constructed their theories around a criticism of the city: Paris for Gravier; big cities, in general, for Meili.

This paper first describes the recurrent critiques of the city in the thoughts of these authors. From sterility to unhealthiness, they combine moral and physical criticisms. Although they belong to different countries and different political cultures, their thoughts take root in surprisingly common backgrounds based on the strength of ruralism and the political context of fascism. Finally, an analysis of their similar propositions concerning town and country planning policies is offered. The lessons of Gravier and Meili are based on different myths which the article will attempt to analyse.     

Very high-order accurate finite volume scheme for the convection-diffusion equation with general boundary conditions on arbitrary curved boundaries

Obtaining very high-order accurate solutions in curved domains is a challenging task as the accuracy of discretization methods may dramatically reduce without an appropriate treatment of boundary conditions. The classical techniques to preserve the nominal convergence order of accuracy, proposed in the context of finite element and finite volume methods, rely on curved mesh elements, which fit curved boundaries. Such techniques often demand sophisticated meshing algorithms, cumbersome quadrature rules for integration, and complex nonlinear transformations to map the curved mesh elements onto the reference polygonal ones. In this regard, the reconstruction for off-site data method, proposed in the work of Costa et al, provides very high-order accurate polynomial reconstructions on arbitrary smooth curved boundaries, enabling integration of the governing equations on polygonal mesh elements, and therefore, avoiding the use of complex integration quadrature rules or nonlinear transformations. The method was introduced for Dirichlet boundary conditions and the present article proposes an extension for general boundary conditions, which represents an important advance for real context applications. A generic framework to compute polynomial reconstructions is also developed based on the least-squares method, which handles general constraints and further improves the algorithm. The proposed methods are applied to solve the convection-diffusion equation with a finite volume discretization in unstructured meshes. A comprehensive numerical benchmark test suite is provided to verify and assess the accuracy, convergence orders, robustness, and efficiency, which proves that boundary conditions on arbitrary smooth curved boundaries are properly fulfilled and the nominal very high-order convergence orders are effectively achieved.     

Improving optimum-path forest learning using bag-of-classifiers and confidence measures

Pattern Analysis and Applications - Machine learning techniques have been actively pursued in the last years, mainly due to the great number of applications that make use of some sort of...     

Constructal design associated with genetic algorithm to minimize the maximum deflection of thin stiffened steel plates

This paper deals with the application of stochastic technique allied to the constructal design (CD) method and computational modeling for the optimization of composed plates reinforced by stiffeners. More specifically, it seeks to determine the optimal geometric configuration of the stiffened plate that minimizes its maximum deflection. For this purpose, a simply supported rectangular plate (with no stiffeners) was adopted as a reference. Then, a set of geometric configurations was proposed, through the application of CD method, by transforming a volume fraction (ϕ) of the reference plate into longitudinal and transverse stiffeners, maintaining the total volume, in-plane dimensions, boundary conditions, and loading. Regarding the optimization procedure, the genetic algorithm (GA) was chosen as the optimization method, and the geometric parameters considered as degrees of freedom were as follows: the number of longitudinal (N_ls) and transverse (N_ts) stiffeners; the thickness of the longitudinal (t_ls) and transverse (t_ts) stiffeners; and longitudinal and transverse stiffeners' heights ratio (h_ts/h_ls). Moreover, several values of ϕ were considered. Results indicated a great influence of the geometry on the mechanical behavior of the stiffened plates, as the optimal geometric configuration obtained here led to a reduction of over 98% in the maximum deflection in comparison with the reference plate.     

SmartSenior: Automatic Content Personalization Through Semi-supervised Learning

Wireless Personal Communications - The adaption of user interface (UI) promises to greatly enhance user experience (UX). This is more evident when we focus on elderly people. However, to date there...