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Let D be a noncommutative finite dimensional F-central division algebra, and let N be a normal subgroup of GLn(D) with n≥1. Given a maximal subgroup M of N, it is proved that either M contains a noncyclic free subgroup, or there exists an abelian subgroup A and a finite family {Ki}1 r of fields properly containing F with Ki* ∩ N ⊃ M for all 1 ≤ i ≤ r such that M/A is finite if Char F = 0 and M/A is locally finite if Char F = p > 0, where A ⊆ K1* ×...× Kr*  

In this paper, analytical expressions are presented to describe the stator and rotor slotting effects on the distribution of Brushless Doubly-Fed Machine's quantities. The effects of rotor slot and loop skewing on the produced torque ripples are then investigated by means of an analytical model considering skew. Torque ripples have considerable effects in the machine operation especially on its starting process and avoid machine from successful starting in some instances. The cogging torque and distortion of the sinusoidal distribution of the magnetic flux density in the air gap, are two principle sources of torque ripples in Brushless Doubly-Fed Machine that are studied. © 2009 Praise... 

In this paper, we complement some recent results of L. Márki, J. Meyer, J. Szigeti and L. van Wyk, by investigating the constant-trace representations of a Clifford algebra C(V) of an arbitrary quadratic form q: V→ F (possibly degenerate) and we present some relevant applications. In particular, the existence of the polynomial identities of C(V) of particular form when the characteristic of the base field is zero is looked at. Furthermore, a lower bound is found on the minimal number t, such that C(V) can be embedded in a matrix ring of degree t, over some commutative F-algebra. Also, some results on the dimension of commutative subalgebras of C(V) are obtained. © 2021, The Author(s), under... 

In this paper we study the structure of locally solvable, solvable, locally nilpotent, and nilpotent maximal subgroups of skew linear groups. In [S. Akbari et al., J. Algebra 217 (1999) 422-433] it has been conjectured that if D is a division ring and M a nilpotent maximal subgroup of D*, then D is commutative. In connection with this conjecture we show that if F[M]F contains an algebraic element over F, then M is an abelian group. Also we show that ℂ* ∪ ℂ*j is a solvable maximal subgroup of real quaternions and so give a counterexample to Conjecture 3 of [S. Akbari et al., J. Algebra 217 (1999) 422-433], which states that if D is a division ring and M a solvable maximal subgroup of D* then... 

Over the last decade, there have been an increasing interest in the techniques of process monitoring of high-quality processes. Based upon the cumulative counts of conforming (CCC) items, Geometric distribution is particularly useful in these cases. Nonetheless, in some processes the number of one or more types of defects on a nonconforming observation is also of great importance and must be monitored simultaneously. However, there usually exist some correlations between these two measures, which obligate the use of multi-attribute process monitoring. In the literature, by assuming independence between the two measures and for the cases in which there is only one type of defect in... 

In this paper, a new structure for the rotor of the Brushless Doubly-Fed Machine (BDFM) is introduced to reduce the machine's torque ripple. The ripple has a considerable effect on the machine start up. At the first section of the paper, analytical expressions for the air gap permeance distribution, the air gap MMF distribution, cogging torque and back EMF are presented. Then, the effects of skewing the rotor loops are analyzed. Finally, the relation between non-skewed quantities and their values in skewed coordinate are introduced  

We investigate the dynamics of a family of one-dimensional linearpower maps. This family has been studied by many authors mainly in the continuous case, associated with Nordmark systems. In the discontinuous case, which is much less studied, the map has vertical and horizontal asymptotes giving rise to new kinds of border collision bifurcations. We explain a mechanism of the interplay between smooth bifurcations and border collision bifurcations with singularity, leading to peculiar sequences of attracting cycles of periods n, 2n, 4n-1, 2(4n-1),···, n ≥ 3. We show also that the transition from invertible to noninvertible map may lead abruptly to chaos, and the role of organizing center in... 

Nowadays, OCR (Optical Character Recognition) is widely used for converting written documents to digital documents. One of the OCR phases is page segmentation. In page segmentation, text regions must be found in input image. In addition, text parts like text columns must be separated. In this paper, a new method for segmenting Persian/Arabic printed text is proposed. This method is based on Ink Spread Effect idea, a new idea that has particular features. Main features of Persian/Arabic scripts are considered in designing this method. This method is skew resistant and can segment text within frames and tables or regions with gray background. © 2006 ICASE  

In this paper, free vibration analysis of thin symmetrically laminated skew plates with fully clamped edges is investigated. The governing differential equation for skew plate which is a fourth order partial differential equation (PDE) is obtained by transforming the differential equation in Cartesian coordinates into skew coordinates. Based on the multi-term extended Kantorovich method (MTEKM) an efficient and accurate approximate closed-form solution is presented for the governing PDE. Application of the MTEKM reduces the governing PDE to a dual set of ordinary differential equations. These sets of equations are then solved with infinite power series solution, in an iterative manner until... 

In this paper, the influence of the excitation angle on the Endurance Time (TCT) analysis of skewed slab-on-girdcr bridges is studied. The excitation of the structure due to the critical angle produces maximum seismic responses that are sometimes significantly higher than the average. The modeled bridges are of slab-on-girder type that are typically used as highway bridges. The bridge models have skew angles of 0, 15, 30, 45, and CO degrees. The ET excitations exerted on structures cover a broad range of hazard levels. The results provide some insight with regard to choosing multiple excitation angles so as to balance computational costs and retain acceptable accuracy for practical design... 

In this paper, the influence of the excitation angle on the Endurance Time (TCT) analysis of skewed slab-on-girdcr bridges is studied. The excitation of the structure due to the critical angle produces maximum seismic responses that are sometimes significantly higher than the average. The modeled bridges are of slab-on-girder type that are typically used as highway bridges. The bridge models have skew angles of 0, 15, 30, 45, and CO degrees. The ET excitations exerted on structures cover a broad range of hazard levels. The results provide some insight with regard to choosing multiple excitation angles so as to balance computational costs and retain acceptable accuracy for practical design... 

In this paper, the dynamic characteristics of skewed bridges are explored analytically. Closed form solutions for translational and torsional periods of free vibration and mode shapes are given for slab-girder skewed bridges. Moreover, the seismic displacement of the deck of skewed bridges is calculated using the response spectrum method and its skew term is compared with the requirement of AASHTO. The effects of seismic force resisting elements, such as elastomeric bearings and end diaphragms are included. It is shown that the skew term in AASHTO's equation can underestimate the seat width requirement for some bridges. A new skew term for the bridge seat width requirement is suggested  

We introduce the concepts of cohering and decohering power of quantum channels. Using the axiomatic definition of the coherence measure, we show that the optimization required for calculations of these measures can be restricted to pure input states and hence greatly simplified. We then use two examples of this measure, one based on the skew information and the other based on the l1 norm; we find the cohering and decohering measures of a number of one-, two-, and n-qubit channels. Contrary to the view at first glance, it is seen that quantum channels can have cohering power. It is also shown that a specific property of a qubit unitary map is that it has equal cohering and decohering power in... 

An accurate approximate closed-form solution is presented for bending of thin skew plates with clamped edges subjected to uniform loading using the extended Kantorovich method (EKM). Successive application of EKM together with the idea of weighted residual technique (Galerkin method) converts the governing forth-order partial differential equation (PDE) to two separate ordinary differential equations (ODE) in terms of oblique coordinates system. The obtained ODE systems are then solved iteratively with very fast convergence. In every iteration step, exact closed-form solutions are obtained for two ODE systems. It is shown that some parameters such as angle of skew plate have an important... 

An effective potential for longitudinal interactions between adjacent protofilaments in a microtubule is introduced. Our proposed interaction potential is a periodic and continuous function of the offset between two protofilaments, which also incorporates the bending energy of protofilaments. This potential produces the results of atomistic simulations. Further, using the potential, a Monte Carlo simulation gives results for the skew angles of observed structures that are in good agreement with experiments. © 2008 The American Physical Society  

Since the product quality of many industrial processes depends upon more than one dependent variable or attribute, they are either multivariate or multi-attribute in nature. Although multivariate statistical process control is receiving increased attention in the literature, little work has been done to deal with multi-attribute processes. In this article, we develop a new methodology to monitor multi-attribute processes. To do this, first we transform multi-attribute data in a way that their marginal probability distributions have almost zero skewness. Then, we estimate the transformed covariance matrix and apply the well-known T2 control chart. In order to illustrate the proposed method... 

In this study, free vibration analysis of moderately thick symmetrically laminated general trapezoidal plates with various combinations of boundary conditions is investigated. The governing partial differential equations and boundary conditions for trapezoidal plate are obtained using first order shear deformation theory (FSDT) together with proper transformation from Cartesian system into trapezoidal coordinates. Generalized differential quadrature (GDQ) method is then employed to obtain solutions for the governing equations. Results of the GDQ method are compared and validated with available results in the literature which show accuracy and fast rate of convergence of the method. Effect of...