Petrographic and petrophysical characterization of some Paleozoic rocks,Um Bogma area,Southwest Sinai,Egypt

Sixty-two samples were collected from the five formations at Um Bogma area, (Southwest Sinai, Egypt). Nine samples were collected from Sarabit El Khedim Formation, ten samples were collected from Abu Hamata Formation, eighteen samples were collected from Adedia Formation, eight samples were collected from Um Bogma Formation and eighteen samples were collected from Abu Thora Formation.The Paleozoic rocks at Um Bogma area, consist mainly of sandstones, siltstones, shales, limestone and dolostones, which are unconformably overlie igneous and metamorphic rocks (granite, diorite and gneiss) of Precambrian age.The petrographic studies were applied to identify different rock units, different facies and its diagenetic history and to reveal its effect on the storage capacity properties. Different types of porosity (oversized, intergranular, fracture and vuggy porosities) have been identified based on the petrographic investigation of the studied thin sections.The Paleozoic sandstone rock samples are characterized by porosity average about 19% for Facies 1 (quartz wack) and about 18%for Facies 2 (quartz arenite) and permeability average 420?mD for Facies 1 (quartz wack) and 690?mD for Facies 2 (quartz arenite), so these rocks can be considered as good reservoir rocks. The Paleozoic carbonate rock samples (Facies 3) are characterized by poor porosity (less than 7%) and very low permeability (less than 0.5?mD), which caused by matrix and diagenetic processes and refer to bad reservoir rocks.Porosity can be linked to the two derived electrical properties (formation resistivity factor and electrical tortuosity) of the studied Paleozoic rocks at Um Bogma area. The electrical tortuosity has significant effects on both permeability and formation resistivity factor. The permeability decreases with increasing electrical tortuosity and the relation between both of them is inverse relationship with good coefficient of correlation. The permeability decreases with increasing electrical tortuosity and the relations between both of them are inverse relationships with high coefficient of correlation. The formation resistivity factor increases with increasing electrical tortuosity and the relations between both of them are positive relationships with a fair to very high coefficient of correlation.     

Control the corrosion of mild steel using synthesized polymers based on polyacrylamide

In this work polyacrylamide (PACM) was prepared by radical polymerization technique using ammonium persulfate (APS) as initiator under nitrogen atmosphere. The viscosity average molecular weight of the prepared PACM was found to be 177858. The free amino groups of PACM, poly(2-methoxyaniline) was grafted by the oxidation of 2-methoxyaniline using APS in acidic medium under nitrogen atmosphere. The grafting percent is found to be 96%. The morphology of the obtained PACM and PACM-g-P2-MeOANI was studied by X-ray diffraction and scanning electron microscope. The grafting process enhances the morphology of both PACM and poly(2-methoxyaniline). The inhibiting effect of the three polymers on the mild steel corrosion in the 1.0?M HCl as aggressive environments have been measured gravimetrically at three different temperatures 25, 40 and 55?°C and electrically at 25?°C. The inhibition efficiencies of the three tested polymers were found to increase with temperature. The poly(2-methoxyaniline) is the most effective one as a corrosion inhibitor at all tested temperatures. The adsorption behavior of the polymers was found to follow Villamil isotherm and the values of the change in free energy refer to a mixed chemical and physical adsorption on the steel surface. Tafel curves indicate that the tested polymers act as mixed anodic and cathodic inhibitor. The double layer capacitance was found to decrease with increasing the inhibitor concentration.     

Interference Evaluation in Cellular Networks

Interference in cellular networks is one of the most common problems in the radio access network. In fact, it is the major issue in cellular networks that affects performances and quality of service. Indeed, interference can be caused by a call on the same frequency from neighboring cell, or a call on an adjacent channel in the same or in neighboring cell. So, we can classify interference on intra-cell interference and inter-cell interference. In 4G, thanks to the use of orthogonal frequency division multiple access and single carrier frequency division multiple access as access techniques in downlink and uplink respectively, intra-cell interference is reduced compared to the inter cell one which caused by the frequency reuse one mechanism and the femto cells deployment. In this work, we will evaluate the interference in different cellular network standards from 2G to 4G.     

Adaptive modulation and decision feedback equalization for frequency‐selective MIMO channels

In this paper, an adaptive modulation scheme for the multiple‐input multiple‐output (MIMO) frequency‐selective channels is investigated. We consider a scenario with precoded block‐based transceivers over spatially correlated Rayleigh multipath MIMO channels. To eliminate the inter‐block interference, the zero‐padding is used. The receiver is equipped with a MIMO minimum‐mean‐squared‐error decision feedback equalizer. The precoder aims to force each subchannel to have an identical signal‐to‐interference‐plus‐noise ratio (SINR). To adjust the constellation size, the unbiased mean square error at the equalizer output is sent back to the transmitter. To simplify our analysis, the feedback channel is considered as instantaneous and error free. We first derive the probability density function of the overall SINR for flat fading and frequency‐selective channels. On the basis of the probability density function of the upper bound of the SINR, we evaluate the system performance. We present accurate closed‐form expressions of the average spectral efficiency, the average bit error rate and the outage probability. The derived expressions are compared with Monte Carlo simulation results. Furthermore, we analyze the effect of the channel spatial correlation. Copyright © 2013 John Wiley & Sons, Ltd.     

Direct and Indirect Exciton Dynamics in Few‐Layered ReS2 Revealed by Photoluminescence and Pump‐Probe Spectroscopy

Atomically thin‐layered ReS₂ with a distorted 1T structure has attracted attention because of its intriguing optical and electronic properties. Here, the direct and indirect exciton dynamics of a three‐layered ReS₂ is investigated by polarization‐resolved transient photoluminescence (PL) and ultrafast pump‐probe spectroscopy. The various time scales of the decay signals of the time‐resolved PL (<10 ps), with monitoring of the populations of electron–hole pairs (exciton), and the transient differential reflectance (≈1 and 100 ps), with monitoring of the populations of electrons and/or holes in the excited states, are observed. These results reveal the characteristic exciton dynamics: rapid relaxation of direct excitons (electron–hole pairs) and slow relaxation of the momentum‐mismatched indirect excitons accompanied by a one‐phonon emission process. These findings provide important information regarding the indirect bandgap nature of few‐layered ReS₂ and its characteristic exciton dynamics, boosting the understanding of the novel electronic and optical properties of atomically thin‐layered ReS₂.     

End-to-end delay margin balancing approach for routing in multi-class networks

This paper presents Quality of Service (QoS) based routing and priority class assignment algorithms. It introduces an end-to-end delay margin balancing approach to routing, and uses it to formulate a nonlinear optimization problem. In a single-class network, the formulation is shown to be convex; however in a multi-class priority network, it is only convex within specific regions, and is infeasible otherwise. A centralized off-line computation technique is proposed to calculate both the route configuration and end-to-end priority assignment. A gradient-based solution in the convex region and a heuristic to overcome the multi-class discontinuity are derived. An approximation of the optimization problem is developed for on-line distributed processing is then presented. Using the approximation, arriving traffic flows can use vector routing tables to search for routes. Compared with minimum-hop, minimum-delay, and min-interference routing algorithms, the proposed approach enables the single-class network to accommodate more users of different end-to-end delay requirements. In a multi-class priority network, results show that using the objective function to combine route and priority class assignment further increases the supportable network traffic volume. Mohamed Ashour received his B.Sc. (1991) and M.Sc. (1997) in Electrical Engineering from Ain Shams University, Cairo, Egypt. He worked for Hughes and General Dynamics as a Telecommunications Engineer. Currently, he is a Ph.D. Candidate in the Department of Electrical and Computer Engineering of McGill University, Montreal, Quebec, Canada. His current area of research is focused on traffic engineering, routing, and QoS provisioning in DiffServ and MPLS Networks. He is also interested in multi-class queuing analysis of long-range traffic, and QoS provisioning in ad hoc networks and satellite communications. Tho Le-Ngoc obtained his B. Eng. (with Distinction) in Electrical Engineering in 1976, his M.Eng. in Microprocessor Applications in 1978 from McGill University, Montreal, and his Ph.D. in Digital Communications 1983 from the University of Ottawa, Canada. During 1977–1982, he was with Spar Aerospace Limited as a Design Engineer and then a Senior Design Engineer, involved in the development and design of the microprocessor-based controller of Canadarm (of the Space Shuttle), and SCPC/FM, SCPC/PSK, TDMA satellite communications systems. During 1982–1985, he was an Engineering Manager of the Radio Group in the Department of Development Engineering of SRTelecom Inc., developed the new point-to-multipoint DA-TDMA/TDM Subscriber Radio System SR500. He was the System Architect of this first digital point-to-multipoint wireless TDMA system. During 1985–2000, he was a Professor the Department of Electrical and Computer Engineering of Concordia University. Since 2000, he has been with the Department of Electrical and Computer Engineering of McGill University. His research interest is in the area of broadband digital communications with a special emphasis on Modulation, Coding, and Multiple-Access Techniques. He is a Senior Member of the Ordre des Ingénieur du Quebec, a Fellow of the Institute of Electrical and Electronics Engineers (IEEE), a Fellow of the Engineering Institute of Canada (EIC), and a Fellow of the Canadian Academy of Engineering (CAE). He is the recipient of the 2004 Canadian Award in Telecommunications Research, and recipient of the IEEE Canada Fessenden Award 2005.     

A Survey on IP Watermarking Techniques

Intellectual property (IP) block reuse is essential for facilitating the design process of system-on-a-chip. Sharing IP designs poses significant high security risks. Recently, digital watermarking emerged as a candidate solution for copyright protection of IP blocks. In this paper, we survey and classify different techniques used for watermarking IP designs. To this end, we defined several evaluation criteria, which can also be used as a benchmark for new IP watermarking developments. Furthermore, we established a comprehensive set of requirements for future IP watermarking techniques.     

The impact of metal-1 plasma processing-induced hot carrierinjection on the characteristics and reliability of n-MOSFETs

We report on plasma processing-induced damage to sub-half-micron n-MOSFETs that is invoked by potential differences between device terminals during metal-1 plasma processing. The damage mechanism is identified as hot carrier (HC) injection promoted by the layout of metal-1 interconnect. Using conventional and modified charge pumping techniques as well as transistor parameter measurements, we also investigate the impact of the damage on device reliability by applying Fowler-Nordheim (FN) and hot carrier stresses. The results show the severe impact of this damage on device reliability, which is attributed to trapping of positive charge at the drain edge that is enough to shorten the device channel     

Rapid thermal annealing applied to the optimization of titanium oxide arc

In this work, rapid thermal annealing (RTA) in the 400–700°C range is used to adjust simultaneously the index and thickness of titanium oxide layers in order to achieve an antireflection coating (ARC) in industrial conditions (large solar cells with a high throughput capability). The technique used for high production rate and low cost coating process is the atmospheric pressure chemical vapor deposition (APCVD) at low temperature.Titanium oxide layers are obtained from the hydrolysis of two precursors, namely the tetraisopropoxide titanate (TPT) and the titanium tetrachloride. In the first case, on silicon substrates at 150°C, we have obtained refractive indices of 1.8–1.9 with layer thicknesses in the range 70–100 nm. In the second case, at 100°C, the refractive index is 2.1–2.2 as deposited and the thickness in the same range. After RTA lasting 120 s at 700°C, the refractive index is 2.25 and the thickness is decreased by 40% with the first precursor, while with chloride, the index increases until 2.4 and the thickness is decreased by 30%. These results are discussed by means of X-ray diffraction and SIMS analysis.