An Engel condition for orderable groups

Let m,n be positive integers, v a multilinear commutator word and w=v^m. We prove that if G is an orderable group in which all w-values are n-Engel, then the verbal subgroup v(G) is locally nilpotent. We also show that in the particular case where v=x the group G is nilpotent (rather than merely locally nilpotent)

A restriction on centralizers in finite groups

For a given m>=1, we consider the finite non-abelian groups G for which |C_G(g):|<=m for every g in G\Z(G). We show that the order of G can be bounded in terms of m and the largest prime divisor of the order of G. Our approach relies on dealing first with the case where G is a non-abelian finite p-group. In that situation, if we take m=p^k to be a power of p, we show that |G|<=p^{2k+2} with the only exception of Q_8. This bound is best possible, and implies that the order of G can be bounded by a function of m alone in the case of nilpotent groups

On the Power-Weighted Efficiency of Multimode Powertrains: A Case Study on a Two-Mode Hybrid System

Multimode powertrains represent one of the most versatile solutions for hybrid electric vehicles where multiple power sources are integrated with aim of improving fuel economy and reducing pollutants emission in every operating condition. Some hybrid powertrain designs feature multiple planetary gear sets whose components can be directly driven by the powertrain actuators (electric motor or thermal engine) or can be connected through clutches and brakes. The advantages due to the availability of multiple modes are mitigated by the increase of production costs and complexity because of the higher number of components required if compared with the single mode solutions. A numerical methodology is adapted from the literature to analyze, categorize, and compare each distinct working configuration. The energy consumption of each powertrain configuration is then evaluated through the power-weighted efficiency concept whose formulation normalize the contribution from each power source. This paper aims at extending the methodology to investigate the operating range for each powertrain configuration to always achieve the maximum efficiency. The methodology is then applied to the realistic case study of the EVT 2-Mode Hybrid System

Phytochemical Screening and Elemental Analysis of Aqueous and Methanolic Extracts of Datura innoxia Seeds and Leaves

The present study is aimed to screen the phytochemicals analysis and elements content of Datura innoxia seeds and leaves. The aqueous and methanol extracts were carried out by using the maceration method and soxhlet apparatus, respectively. Results of the study of Phytochemical screening revealed the presence of a high concentration of alkaloids, flavonoids, tannins, steroids and triterpines, and low concentration of saponin and coummarins. The elements in the leaves and seeds (K, Ca, S, Si, Cl, Fe, Al, P, Mg, Ti, Mn, Zn, Sr, Cu, V, Br, and Zr) were determined by energy-dispersive X-ray fluorescence (EDXRF) spectroscopy. K content was the highest in seeds (5.469 ± 0.021%), Ca and S the highest in leaves (2.461 ± 0.019 %, 1.254 ± 0.022 %, respectively). The elements Ti, Mn, Sr, V, Br, and Zr were detected in the leaves with range concentration 0.062-0.002 %. The elements Si, Cl, Fe, Al, P, Mg, and Zn concentration in seeds varied from 0.002 to 0.942% and in leaves varied from 0.014 to 0.346%. The concentration of these elements did not exceed the standard of dangerous toxic levels

Steering Behavior of an Articulated Amphibious All-Terrain Tracked Vehicle

This paper presents a study related to an Articulated Amphibious All-Terrain Tracked Vehicle (ATV) characterized by a modular architecture. The ATV is composed by two modules: The first one hosts mainly the vehicle engine and powertrain components, meanwhile the second one can be used for goods transportation, personnel carrier, crane and so on. The engine torque is transmitted to the front axle sprocket wheel of each module and finally distributed on the ground through a track mechanism. The two modules are connected through a multiaxial joint designed to guarantee four relative degrees of freedom. To steer the ATV, an Electro Hydraulic Power System (EHPS) is adopted, thus letting the vehicle steerable on any kind of terrain without a differential tracks speed. The paper aims to analyze the steady-state lateral behavior of the ATV on a flat road, through a non-linear mathematical vehicle model built in Matlab/Simulink environment. The model describes the vehicle main planar motion and the interaction between the two modules through the application of a hydraulic steering torque. The model simulates steady-state handling maneuvers in Matlab/Simulink. Two scenarios are considered: One with the application of an open-loop hydraulic steering torque without any vehicle feedback; the second one with a closed-loop steering torque actuation based on the relative angle between the two modules (hitch angle). Finally, the influence of the ATV longitudinal speed on vehicle lateral characteristics is also presented

Finite spin-glass transition of the ±J\pm J XY model in three dimensions

A three-dimensional $\pm J$ XY spin-glass model is investigated by a nonequilibrium relaxation method. We have introduced a new criterion for the finite-time scaling analysis. A transition temperature is obtained by a crossing point of obtained data. The scaling analysis on the relaxation functions of the spin-glass susceptibility and the chiral-glass susceptibility shows that both transitions occur simultaneously. The result is checked by relaxation functions of the Binder parameters and the glass correlation lengths of the spin and the chirality. Every result is consistent if we consider that the transition is driven by the spin degrees of freedom.Comment: 11 pages, 8 figures, incorrect arguments are delete