Design Optimization of Secondary Element of Single-Sided Linear Induction Motors Using a Genetic Algorithm

The article focuses on the use of genetic algorithms for the design of linear induction motors. Comparison of genetic algorithm with classical methods in the context of electrical machines designing has been carried out. The results of solving an optimization problem for two designs are presented, viz. a laboratory linear induction electric motor based on a three-phase SL-5-100 inductor and a traction single-sided linear induction electric motor of an urban transport system. The optimality criterion included maximizing the power factor and efficiency, as well as the rigidity of the mechanical characteristic while ensuring a starting traction force of at least a set value. The results of optimization of such parameters of the secondary element as the width and thickness of the conductive strip as well as the thickness of the magnetic circuit are described. The relevance of the problem of optimizing the parameters of the secondary element with unchanged parameters of the inductor is due to the fact that the same inductor can be used to build various structures, while the secondary element is created for each specific application and integrated directly into the working body of the mechanism or is a driven product. To calculate the traction and energy characteristics of linear induction electric motors, an electromagnetic model based on detailed equivalent circuits was used, taking into account longitudinal and transverse edge effects and providing a calculation time for one set of parameters of about 1 s. In accordance with this model, the electric motor is reduced to a set of three detailed equivalent circuits: a magnetic circuit, primary and secondary electrical circuits. The result of the optimization of these electric motors was an increase in the efficiency by 1.6 and 1.4 %, respectively, an increase in the power factor by 0.9 and 0.2 %, and an increase in the rigidity of traction characteristics and starting traction force.

Numerical and Experimental Study of the Blade Profile of a Savonius Type Rotor Implementing a Multi-Blade Geometry

In the present study, the implementation of multi-blade profiles in a Savonius rotor was evaluated in order to increase the pressure in the blade’s intrados and, thus, decrease motion resistance. The geometric proportions of the secondary element were determined, which maximized the rotor’s performance. For this, the response surface methodology was used through a full factorial experimental design and a face-centered central composite design, consisting of three factors, each with three levels. The response variable that was sought to be maximized was the power coefficient (CP), which was obtained through the numerical simulation of the geometric configurations resulting from the different treatments. All geometries were studied under the same parameters and computational fluid dynamics models through the ANSYS Fluent software. The results obtained through both experimental designs showed a difference of only 1.06% in the performance estimates using the regression model and 3.41% when simulating the optimal proportions geometries. The optimized geometry was characterized by a CP of 0.2948, which constitutes an increase of 10.8% in its performance compared to the profile without secondary elements and of 51.2% compared to the conventional semicircular profile. The numerical results were contrasted with experimental data obtained using a wind tunnel, revealing a good degree of fit.

Materializing the Invisible: Landscape Painting in Viceregal Peru as Visionary Painting

Landscape painting in Peru typically does not receive much attention from critical dis-course, even though the adoption of the Flemish landscape by Andean viceregal painters became a distinctive feature of Peruvian painting of the second half of the 17th century. Considered a consequence of a change in the artistic taste of viceregal society, the landscape was perceived as a secondary element of the composition. In this article, we will analyze the inclusion of the Flemish landscape in Andean religious painting from another critical perspective that takes into account different spiritual processes that colonial religiosity goes through. We analyze how the influence of the Franciscan and Jesuit mysticism created a fertile ground where landscape painting could develop in Peru. The Andean viceregal painters found in the landscape an effective way to visualize suprasensible spiritual experiences and an important device for the development in Peru of a painting with visionary characteristics.

Characterizing a novel SCC mec with a composite structure from a clinical strain of Staphylococcus hominis , C34847

Staphylococcal cassette chromosome mec (SCC mec ) has predominantly been described in methicillin-resistant Staphylococcus aureus . However, studies have indicated that coagulase-negative staphylococci (CoNS) carry a larger diversity of SCC elements. We characterized a composite SCC mec element carrying an uncharacterized ccr1 and type A mec gene combination, in conjunction with a secondary element bearing ccr4 , from a clinical strain of S. hominis . The element’s complex structure points to a high degree of recombination occurring in SCC mec in CoNS.

Starting forces of the traction linear induction motor with adjustable resistance of the short-circuited winding of the secondary element

Background: Development and research of linear traction drives for Maglev transport is an urgent task. Linear induction motors can be used as traction machines for advanced rolling stock. Aim: Study of the starting characteristics of an adjustable traction linear induction motor with variable resistance by a short-circuited winding of the secondary element. Methods: Theoretically, relations were obtained for calculating the traction starting forces of an adjustable linear induction motor with various designs of a short-circuited winding of the secondary element. Results: Based on the obtained ratios, the calculations of the starting traction forces of linear induction motors intended for use in promising modes of transport were performed. Conclusion: The results of calculating the starting traction forces of adjustable linear induction motors make it possible to reasonably select the modes of starting the motor depending on the design of the secondary winding.

Stepper induction motors for electric drive

Aim: The goal is to present a new asynchronous principle of operation of stepper motors, based on the use of counter-rotating (or traveling) magnetic fields. Method: A change in the degree of symmetry of one of these magnetic fields leads to the fact that the armature (rotor or secondary element) makes a precise discrete movement. Result: The force moving the armature of a stepper induction motor is created as a result of the interaction of eddy currents in the armature with a rotating or traveling magnetic field. Stepper induction motors can rotate the rotor at a certain angle and discretely move flat or cylindrical electrically conductive armatures, which can be smooth and non-magnetic. A separate group of motors for a discrete electric drive is made up of two-coordinate linear stepping asynchronous machines, which also operate using the same counter-running magnetic fields both in the longitudinal and transverse directions. Conclusion: The features of the design of such electric machines are presented, the values of the magnetic induction in different zones of a two-coordinate stepper motor are determined, the relations for calculating the steps of the armature in both the longitudinal and transverse directions are given.

Notas sobre el pragmatismo de Erving Goffman y su concepto de estigma

El presente artículo trata las influencias del pragmatismo en el concepto de Estigma de Erving Goffman. El objetivo principal es develar el influjo de la corriente filosófica norteamericana en la configuración de uno de los conceptos más importantes de este sociólogo canadiense. Para ello, el texto aborda algunos de los postulados más destacados de G.H. Mead y de la Escuela de Chicago, particularmente de algunos de los exponentes del Interaccionismo simbólico. En términos metodológicos, se realizó una revisión hermenéutica de los textos más relevantes de los autores analizados en miras de hallar en ellos los conceptos que permitan construir un puente de diálogo entre perspectivas. En la parte final del texto, se puede apreciar que el pragmatismo no es sólo un elemento secundario en la obra de Goffman, sino que se encuentra en el centro de la configuración del concepto de estigma. -- This essay treats the influence of the pragmatism on the concept of stigma from Erving Goffman. The main objective is to show the influx of this philosophical perspective in the configuration of one of the mains aspects of this Canadian sociologist. For that, the texts aboard some of the proposition of G. H. Mead and the Chicago School, specifically some of the most important exponents from the last. In methodological terms I made a hermeneutic revision of the most relevant texts of this author to find in them some concepts that allow build a dialogue bridge between these perspectives. In the final part of this essay, we can appreciate that the pragmatism is not a secondary element of Goffman`s oeuvres but is one of the most important in the configuration of stigma concept.

The Passion in Film

In general film treatments of the Passion fall into a few categories or types. Obviously, these categories are general characterizations of approaches, and may sometimes overlap. (1) During the first fifty years of the genre’s existence, most “Jesus” films took a traditional religious approach, being more or less faithful to the Gospels. (2) In the latter part of the twentieth century films increasingly attempted to treat the Passion as a realistic narrative. (3) Others deal with the Passion as a historical narrative that also functions as a “myth” with universal significance. (4) The story of Jesus’ crucifixion may be combined with explicitly fictional elements. (5) The Passion is also represented in a theatrical context. (6) In a number of films the Passion of Christ figures as a secondary element in a story about another figure or event. (7) Finally, there are films not about the Passion itself but about portraying the Passion.

Reliable cryo-EM resolution estimation with modified Fourier shell correlation

A modified Fourier shell correlation (mFSC) methodology is introduced that is aimed at addressing two fundamental problems that mar the use of the FSC: the strong influence of mask-induced artifacts on resolution estimation and the lack of assessment of FSC uncertainties stemming from the inability to determine the associated number of degrees of freedom. It is shown that by simply changing the order of the steps in which the FSC is computed, the correlations induced by masking of the input data can be eliminated. In addition, to further reduce artifacts, a smooth Gaussian window function is used to outline the regions of reciprocal space within which the mFSC is computed. Next, it is shown that the number of degrees of freedom (ndf) of the system is approximated well by combining the ndf associated with the Gaussian window in reciprocal space with further reduction of the ndf owing to the use of the mask in real space. It is demonstrated through the application of the mFSC to both single-particle and helical structures that the mFSC yields reliable, mask-induced artifact-free results as a result of the introduced modifications. Since the adverse effect of the mask is eliminated, it also becomes possible to compute robust local resolutions both per voxel of a 3D map as well as, in a newly developed approach, per functional subunit, segment or even larger secondary element of the studied complex.

Fatigue Crack Growth Rate, Microstructure and Mechanical Properties of Diverse Range of Aluminum Alloy: A Comparison

In practice for all metallic materials, damage by fatigue usually takes in two steps, the appearance of an initial crack which then grows as a function of the present microstructure. The objective of this study is to identify the elements influencing the fatigue crack growth rate on aluminum alloys of different microstructures. Characterization tests and microstructural analysis on 2024-T3, 5083-H22, 6082-T6 and 7075-T6 shades have been carried out. Based on the experimental results obtained, AA7075-T6 has the best fatigue crack rate resistance which is explained by its behavior as well as the nature and dispersive distribution of the secondary element.