In the present work, the corrosion behavior
of aluminium alloy engine block in 3.5% NaCl solution was studied. The work was
carried out using conventional gravimetric measurements and complemented by
scanning electron microscopy (SEM) and X-ray analyzer (EDX) investigations. The
results obtained indicate that the main process the alloy undergoes, under the
medium of exposure studied, is related to localized corrosion that takes place
as a consequence of the process of alkalinization around the cathodic
precipitates existing in the alloy. The alloy suffers a process of corrosion
localized to the area surrounding the precipitates of the Al (Si, Mg) and
Al-Mg, which resulted in hemispherical pits. This identification was confirmed
by SEM and EDX analysis. No evidence was found of the formation of crystallographic
pitting for exposure times up to 54 days. Gravimetric analysis confirmed that
with varying exposure periods the weight loss of the alloy increases and the
corrosion rate decreases with time.

Abstract:
The in vitro antioxidant activity of the roots and rhizomes of Cyperus rotundus L. has been investigated by estimating degree of non-enzymatic haemoglobin glycosylation, measured colorimetrically at 520 nm. The ethanol extract of the roots and rhizomes of C. rotundus showed higher activity, than other extracts of it. The antioxidant activity of the extracts are close and identical in magnitude, and comparable to that of standard antioxidant compounds used.

Abstract:
The main idea of the present paper is to compute the spectrum and the fine spectrum of the generalized difference operator over the sequence spaces . The operator denotes a triangular sequential band matrix defined by with for , where or , ; the set nonnegative integers and is either a constant or strictly decreasing sequence of positive real numbers satisfying certain conditions. Finally, we obtain the spectrum, the point spectrum, the residual spectrum, and the continuous spectrum of the operator over the sequence spaces and . These results are more general and comprehensive than the spectrum of the difference operators , , , , and and include some other special cases such as the spectrum of the operators , , and over the sequence spaces or . 1. Introduction, Preliminaries, and Definitions In analysis, operator theory is one of the important branch of mathematics which has vast applications in the field applied science and engineering. Operator theory deals with the study related to different properties of operators such as their inverse, spectrum, and fine spectrum. Since the spectrum of a bounded linear operator generalizes the notion of eigen values of the corresponding matrix, therefore, the study of spectrum of an operator takes a prominent position in solving many scientific and engineering problems. Hence, mathematicians and researchers have devoted their works in achieving new ideas and concepts in the concerned field. For instance, the fine spectrum of the Cesàro operator on the sequence space for has been studied by Gonzalez [1]. Okutoyi [2] computed the spectrum of the Cesàro operator over the sequence space . The fine spectra of the Cesàro operator over the sequence space have been determined by Akhmedov and Ba？ar [3]. Akhmedov and Ba？ar [4, 5] have studied the fine spectrum of the difference operator over the sequence spaces and , where . Altay and Ba？ar [6] have determined the fine spectrum of the difference operator over the sequence spaces , for . The fine spectrum of the difference operator over the sequence spaces and was investigated by Kayaduman and Furkan [7]. Srivastava and Kumar [8] have examined the fine spectrum of the generalized difference operator over the sequence space . Recently, the spectrum of the generalized difference operator over the sequence spaces and has been studied by Dutta and Baliarsingh [9, 10], respectively. The main focus of this paper is to define the difference operator and establish its spectral characterization with respect to the Goldberg’s classifications. Let be either constant or strictly

Abstract:
In the present work the generalized weighted mean difference operator has been introduced by combining the generalized weighted mean and difference operator under certain special cases of sequences and . For any two sequences and of either constant or strictly decreasing real numbers satisfying certain conditions the difference operator is defined by with for all . Furthermore, we compute the spectrum and the fine spectrum of the operator over the sequence space . In fact, we determine the spectrum, the point spectrum, the residual spectrum, and the continuous spectrum of this operator on the sequence space . 1. Introduction, Preliminaries, and Definitions Let and be two bounded sequences of either constant or strictly decreasing positive real numbers such that and for all , and By and , we denote the spaces of all absolutely summable and p-bounded variation series, respectively. Also, by , , and , we denote the spaces of all bounded, convergent, and null sequences, respectively. The main perception of this paper is to introduce the weighted mean difference operator as follows. Let be any sequence in , and we define the weighted mean difference transform of by where denotes the set of nonnegative integers and we assume throughout that any term with negative subscript is zero. Instead of writing (3), the operator can be expressed as a lower triangular matrix , where Equivalently, in componentwise the triangle can be represented by The main objective of this paper is to determine the spectrum of the operator over the basic sequence space . The operator has been studied by Polat et al. [1] in detail by introducing the difference sequence spaces , , and . In the existing literature several researchers have been actively engaged in finding the spectrum and fine spectrum of different bounded linear operators over various sequence spaces. The spectrum of weighted mean operator has been studied by Rhoades [2], whereas that of the difference operator over the sequence spaces for and , has been studied by Altay and Ba？ar [3, 4]. Kayaduman and Furkan [5] have determined the fine spectrum of the difference operator over the sequence spaces and and on generalizing these results, Srivastava and Kumar [6, 7] have determined the fine spectrum of the operator over the sequence spaces and , where is a sequence of either constant or strictly deceasing sequence of reals satisfying certain conditions. Dutta and Baliarsingh [8–10] have computed the spectrum of the operator ( ) and over the sequence spaces , , and , respectively. The fine spectrum of the generalized

Abstract:
We propose a new scenario in which the dominant signal for supersymmetry at the Tevatron are the events having two or three $\tau$ leptons with high $p_T$ accompanied by large missing transverse energy. This signal is very different from the multijet or multileptons (involving $e$ and/or $\mu$ only) or the photonic signals that have been extensively investigated both theoretically and experimentally. A large region of the GMSB parameter space with the lighter stau as the NLSP allow this possibility. Such a signal may be present in the past Tevatron data to be analyzed.

Abstract:
We investigate the texture of fermion mass matrices in theories with partial unification (for example $ SU(2)_L\times SU(2)_R\times SU(4)_c$) at a scale $\sim 10^{12}$ GeV. Starting with the low energy values of the masses and the mixing angles, we find only two viable textures with atmost four texture zeros. One of these corresponds to a somewhat modified Fritzsch textures. A theoretical derivataion of these textures leads to new interesting relations among the masses and the mixing angles.

Abstract:
In this paper, we address the role of electron-electron interactions on the velocities of spin and charge transport in one-dimensional systems typified by conjugated polymers. We employ the Hubbard model to model electron-electron interactions. The recently developed technique of time dependent Density Matrix Renormalization Group (tdDMRG) is used to follow the spin and charge evolution in an initial wavepacket described by a hole doped in the ground state of the neutral system. We find that the charge and spin velocities are different in the presence of correlations and are in accordance with results from earlier studies; the charge and spin move together in the noninteracting picture while interaction slows down only the spin velocity. We also note that dimerization of the chain only weakly affects these velocities.