43 research outputs found
Analysis and design of a two-speed single-phase induction motor with 2 and 18 pole special windings
No full textThe motor presented employs multiple independent windings for operation with two very different pole numbers. The 18-pole field is produced with a symmetrical three-phase winding connected in a Steinmetz arrangement to a single-phase supply. A unified analysis method has been developed and used to demonstrate the equivalence of a Steinmetz delta or star connection with a main and auxiliary winding of a single-phase motor. The method has been experimentally validated and also included are some specific motor design considerations
Computation of core losses in electrical machines using improved models for laminated steel
No full textTwo new models for specific power losses in cold-rolled motor lamination steel are described together with procedures for coefficient identification from standard multifrequency Epstein or single sheet tests. The eddy-current and hysteresis loss coefficients of the improved models are dependent on induction (flux density) and/or frequency, and the errors are substantially lower than those of conventional models over a very wide range of sinusoidal excitation, from 20 Hz to 2 kHz and from 0.05 up to 2 T. The model that considers the coefficients to be variable, with the exception of the hysteresis loss power coefficient that has a constant value of 2, is superior in terms of applicability and phenomenological support. Also included are a comparative study of the material models on three samples of typical steel, mathematical formulations for the extension from the frequency to the time domain, and examples of validation from electrical machine studies
Precision Agriculture Applications in a High Density Olive Grove Adapted for Mechanical Harvesting in Greece
No full textAbstractWorldwide olive production recently has undergone major changes in terms of harvesting technologies and planting densities. A new educational, research and exhibition olive grove was established at Perrotis College, Greece in 2010 to evaluate new production systems under a variety of planting densities and major input treatments for two of the most commonly used olive varieties globally, under high density palnting systems adapted for mechanical harvesting. Precision agriculture practices were used in this olive grove, to identify possible “zones of variation” for yield, crop reflectance using the handheld GreenSeeker® NDVI sensor and for soil moisture and electrical conductivity. The results are presented herein for the second year after planting and they indicated distinctive zones of variability for the measured characteristics. These zones will be considered and further validated in the current season, to provide alternative management practices for optimization of olive production and combined with additional soil and agronomic parameters
The Cuntz algebra Q_N and C*-algebras of product systems
No full textWe consider a product system over the multiplicative group semigroup N^x of Hilbert bimodules which is implicit in work of S. Yamashita and of the second named author. We prove directly, using universal properties, that the associated Nica-Toeplitz algebra is an extension of the C*-algebra Q_N introduced recently by Cuntz
The Cuntz algebra Q_N and C*-algebras of product systems
No full textWe consider a product system over the multiplicative group semigroup N^x of Hilbert bimodules which is implicit in work of S. Yamashita and of the second named author. We prove directly, using universal properties, that the associated Nica-Toeplitz algebra is an extension of the C*-algebra Q_N introduced recently by Cuntz
INTERNATIONAL TRADE OF ROMANIA IN THE CONTEXT OF ITS LOW ECONOMIC POTENTIAL
No full textThe study provides a view on Romanian economy in terms of its competitiveness and potential for sustaining an efficient foreign trade. After reviewing literature and the reports of prestigious institutions and bodies in the area, the author presents several elements providing an accurate image on current quantitative and qualitative parameters of Romanian foreign trade, the internal and foreign processes influencing it and its main trends. The theoretical, legislative and institutional background of the paper was developed earlier by the author in his monograph - "The legal and financial regime applicable to international foreign trade" published in 2008 by ArtPress Publishing House after Romania joined the European Union. In this study, however, the focus is placed on major changes that have occurred in Romania’s foreign trade after it joined the European structures
High amplitude oscillating magnetic field applicator for remote magnetic nanoparticle detection
No full textStatic Analysis of the Structure Type Tank Thermally
No full textThis paper consider finite element analysis for structural analysis of a tank under thermal loadings. Geometric modeling is done in CATIA and for finite element analysis the author used FEA module in Catia. The aim is to determine von Mises stress field, deformed mesh and thermal loadings
Special Issue “Audit and Financial Control Tools Aimed at Ensuring the Sustainable Performance of Organizations”
No full textThrough this editorial, the author aims to present the main landmarks related to the scientific contributions that can be found in the special issue dedicated to the topic “Audit and Financial Control Tools Aimed at Ensuring the Sustainable Performance of Organizations” [...
Book Review - SUSTAINABLE DEVELOPMENT AND GREEN BUSINESSES
No full textWhen he started to elaborate the work Sustainable Development & Green Businesses (Accent Publishing House, Cluj-Napoca, 2014, 124 pp., in "academic" format), the author Professor Ionel Bostan bore in mind the claims of his master, Professor Ion Pohoaţă, i.e. "by itself, development is not opposed to environment and, therefore, development does not have to pay any pollution tribute. Underdevelopment, people’s ignorance, their way of thinking and acting, etc. may represent as many causes for the deterioration of the environment and life in general, as development, by the financial resources created, can provide the source for the establishment and support of antipollution means and measures"
