Paraxial propagation in amorphous optical media with screw dislocation

We study paraxial beam propagation parallel to the screw axis of a dislocated amorphous medium that is optically weakly inhomogeneous and isotropic. The effect of the screw dislocation on the beam's orbital angular momentum is shown to change the optical vortex strength, rendering vortex annihilation or generation possible. Furthermore, the dislocation is shown to induce a weak \textit{biaxial} anisotropy in the medium due to the elasto-optic effect, which changes the beam's spin angular momentum as well as causing precession of the polarization. We derive the equations of motion of the beam and demonstrate the optical Hall effect in the dislocated medium. Its application with regard to determining the Burgers vector as well as the elasto-optic coefficients of the medium is explained

The quality of image encryption techniques by reasoned logic

One form of data is digital images, because of their widespread of frequent exchange over the internet it is necessary to preserve the security and privacy of the images transmitted.There are many image encryption techniques that have different security levels and there are many standards and protocols fortesting the quality of encryption security. The cipher images can be evaluated using various quality measuring criteria, these measures quantify certain features of the image. If there are many methods that can be applied to secure images; the question is what is the most powerful scheme that can be use damong these methods? This research try to answer this question by taking three different encryption methods (rivest cipher 5 (RC5), chaotic and permutation) and measure their quality using the peek signal to noise ratio (PSNR),correlation, entropy, number of pixels changes rate (NPCR) and unified average changing intensity (UACI), the results of these criteria were input to a fuzzy logic system that was used to find the best one among them

Compositional homogeneity in a medical-grade stainless steel sintered with a Mn-Si additive

Cataloged from PDF version of article.In this paper, chemical composition uniformity in amorphous/nanocrystallization medical-grade stainless steel (ASTM ID: F2581) sintered with a Mn–Si additive was studied via scanning electron microscopy, energy dispersive X-ray spectroscopy, and transmission electron microscopy. The results show that as a result of sintering at 1000 °C, no dissociation of Mn–Si additive particles embedded in the stainless steel matrix occurs. In contrast, sintering at 1050 °C develops a relatively homogeneous microstructure from the chemical composition viewpoint. The aforementioned phenomena are explained by liquation of the Mn–Si eutectic additive, thereby wetting of the main powder particles, penetrating into the particle contacts and pore zones via capillary forces, and providing a path of high diffusivity. © 2012 Elsevier B.V. All rights reserved

Endothelial nitric oxide synthase gene Glu298Asp polymorphism and risk of preeclampsia in South East of Iran

Preeclampsia (PE) is the most serious complication of pregnancy that causes maternal and fetal morbidity and mortality. Although the exact pathophysiology of PE is unknown, a large number of studies have shown that abnormalities in nitric oxide (NO) synthesis may contribute to the development of this disorder. There are some evidences that polymorphisms of the endothelial nitric oxide synthase (eNOS) gene affect NO production and have been associated with hypertension and PE in some populations. Therefore the aim of this study was to assess the relation of the Glu298Asp eNOS polymorphism and PE in an Iranian population. We compared the frequency of the Glu298Asp polymorphism in 147 women with PE and 137 healthy pregnant control subjects by polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP) method. The frequencies of Glu298Asp genotypes were significantly different between PE women and controls (p < 0.001). The frequency of Asp allele was 0.32 in PE patients and 0.20 in controls and was significantly different (p < 0.001). The risk of PE was 2.4 fold in pregnant women with Asp allele. In conclusion, the Asp allele could be a risk factor for PE in South East of Iran.Key words: Nitric oxide synthase, polymorphism, preeclampsia, pregnancy

Liquid-phase sintering of medical-grade P558 stainless steel using a new biocompatible eutectic additive

Cataloged from PDF version of article.One of the effective approaches to reduce residual pores in powder metallurgy parts is activated liquidphase sintering process using proper additives. In this work, for the first time, a new biocompatible additive (Mn–11.5 wt.% Si, a eutectic alloy) is experimented for liquid-phase sintering of nanocrystalline/amorphous P558 stainless steel powders. It is realized that by increasing the sintering aid content and temperature, the density is effectively increased: a sharp densification progress when the sintering temperature increases from 1000 °C to 1050 °C and a slower densification rate when it exceeds 1050 °C. This preliminary study opens up the development of high-density medical-grade stainless steels produced by powder metallurgy, where suitable additives can lower sintering temperature and time, which is promising for retarding grain growth and commercial applications. © 2012 Elsevier B.V. All rights reserve

Fabrication of Nanostructured Medical-Grade Stainless Steel by Mechanical Alloying and Subsequent Liquid-Phase Sintering

Cataloged from PDF version of article.This article focuses on the microstructure of medical-grade P558 (ASTM F2581) stainless steel produced by mechanical alloying and liquid-phase sintering. Rietveld X-ray diffraction and transmission electron microscopy reflect that the mechanically alloyed stainless steel powder is a nanocrystal dispersed amorphous matrix composite.Mn-11.5 wt pct Si eutectic alloy as additive improves densification of the synthesized P558 alloy via liquid-phase sintering mechanism. X-ray mapping shows that after sintering at 1323 K (105°C) for 1 hour, a uniform distribution of dissolved Mn and Si is achieved. Moreover, the development of a nanostructured, fully austenitic stainless steel after sintering at the same temperature is realized by X-ray diffraction and transmission electron microscopy. © The Minerals, Metals & Materials Society and ASM International 201

Federated mmWave Beam Selection Utilizing LIDAR Data

Efficient link configuration in millimeter wave (mmWave) communication systems is a crucial yet challenging task due to the overhead imposed by beam selection. For vehicle-to-infrastructure (V2I) networks, side information from LIDAR sensors mounted on the vehicles has been leveraged to reduce the beam search overhead. In this letter, we propose a federated LIDAR aided beam selection method for V2I mmWave communication systems. In the proposed scheme, connected vehicles collaborate to train a shared neural network (NN) on their locally available LIDAR data during normal operation of the system. We also propose a reduced-complexity convolutional NN (CNN) classifier architecture and LIDAR preprocessing, which significantly outperforms previous works in terms of both the performance and the complexity