Enhancement in Magnetic Properties of Mg-Doped Strontium-Substituted Bismuth Ferrite Prepared by Solid-State and Sol-Gel Methods

We report a potential way to effectively improve the magnetic properties of BiSrFeO3 (BSFO) through Mg ²⁺ ion substitution at the Fe sites of BFO lattice. Polycrystalline Bi_0.95Sr_0.05Fe_0.98Mg_0.02 O ₃ (BSFMO) powder was prepared through optimized solid-state (SS) and sol-gel (SG) reaction methods. The effect of preparation routes on the crystal purity and multiferroic properties of the BSFMO was investigated. The purity and structural changes induced by Mg doping are confirmed by X-ray powder diffractometer and IR spectra. Enhanced magnetic properties are observed in Mg-substituted samples, which simultaneously exhibit ferromagnetic and superparamagnetic properties at room temperature. The improved magnetic properties and soft nature obtained by Mg doping in BSFO particles demonstrate the possibility of BFO particles to practical applications.     

Texturing and Instant Cooling of Rapeseed as Pretreatment Prior to Pressing and Solvent Extraction of Oil

Instant controlled pressure drop process (DIC) was used to texture rapeseeds in order to intensify oil extraction performances of both pressing and solvent extraction processes. Solvent extraction from both DIC-textured and non-treated raw material RM seeds was achieved with n-hexane using separately accelerated solvent extraction (ASE) and dynamic maceration (DM). ASE allowed quantifying the extraction yields while the extraction kinetics issued from DM experimental data was studied through coupled washing/diffusion CWD phenomenological model. ASE oil contents were 622.5?±?0.5 and 664.4?±?0.5 g oil/kg dry dry basis ddb for untreated and DIC-textured seeds, respectively. In terms of kinetics, 45-min DM of DIC-treated seeds implied higher yields than 8-h DM of RM (467.8?±?0.5 against 435.6?±?0.5 g oil/kg ddb). Moreover, pressing oil yields reached 553.5?±?0.5 against 490?±?0.5 g oil/kg ddb for DIC and RM seeds, respectively. Besides, optimized DIC treatment allowed obtaining preservation of lipid fatty acid profiles.     

A Methodology for a Semi-Automatic Evaluation of the Lexicons of Machine Translation Systems

The lexicon is a major part of any Machine Translation (MT) system. If the lexicon of an MT system is not adequate, this will affect the quality of the whole system. Building a comprehensive lexicon, i.e., one with a high lexical coverage, is a major activity in the process of developing a good MT system. As such, the evaluation of the lexicon of an MT system is clearly a pivotal issue for the process of evaluating MT systems. In this paper, we introduce a new methodology that was devised to enable developers and users of MT Systems to evaluate their lexicons semi-automatically. This new methodology is based on the idea of the importance of a specific word or, more precisely, word sense, to a given application domain. This importance, or weight, determines how the presence of such a word in, or its absence from, the lexicon affects the MT system's lexical quality, which in turn will naturally affect the overall output quality. The method, which adopts a black-box approach to evaluation, was implemented and applied to evaluating the lexicons of three commercialEnglish–Arabic MT systems. A specific domain was chosen in which the various word-sense weights were determined by feeding sample texts from the domain into a system developed specifically for that purpose. Once this database of word senses and weights was built, test suites were presented to each of the MT systems under evaluation and their output rated by a human operator as either correct or incorrect. Based on this rating, an overall automated evaluation of the lexicons of the systems was deduced.     

Emotion recognition in Arabic speech

Automatic emotion recognition from speech signals without linguistic cues has been an important emerging research area. Integrating emotions in human–computer interaction is of great importance to effectively simulate real life scenarios. Research has been focusing on recognizing emotions from acted speech while little work was done on natural real life utterances. English, French, German and Chinese corpora were used for that purpose while no natural Arabic corpus was found to date. In this paper, emotion recognition in Arabic spoken data is studied for the first time. A realistic speech corpus from Arabic TV shows is collected. The videos are labeled by their perceived emotions; namely happy, angry or surprised. Prosodic features are extracted and thirty-five classification methods are applied. Results are analyzed in this paper and conclusions and future recommendations are identified.     

Wireless propagation channel modeling for optimized Handoff algorithms in wireless LANs

In this paper, we present a time-series analysis technique which covers the basic concepts and mechanisms driving the wireless propagation channel. We also use a generated series for simulation study of Handoff performance showing the impact of multipath phenomena. Moreover, the extraction of the average signal has been used to reduce significantly the number of unnecessary Handoffs.The wireless propagation channel modeling is based on the linear model concept of the received power from the access point (AP). This concept has a crucial role in modeling new decentralized Handoff based on the ratio of expected and current signal slopes already provided by the linear model. Hence, a fuzzy-based solution is developed and a comparison with the analytical solution results is established. Until recently, Handoff mechanisms are implemented entirely in software, which increasingly becoming infeasible. Therefore, this work attempt to follow the top-down co-design approach providing hardware prototype which leads to reduce the power consumption and support high processing speed.     

Characteristics of Oxyfuel and Air–Fuel Combustion in an Industrial Water Tube Boiler

The characteristics of oxyfuel combustion and air–fuel combustion in the furnace of a typical industrial water tube boiler using methane as the operating fuel are investigated. Two oxyfuel cases are considered. The analysis is conducted for two oxyfuel cases that correspond to 21% O₂ and 29% O₂ in the oxidizer mixture (O₂ + CO₂). A renormalized group (RNG) turbulence model and the eddy dissipation model are utilized in the present work to provide the turbulence characteristics and the production rate of species. The solution of the radiative transfer equation was obtained using the discrete ordinates radiation model. The set of governing equations and the boundary conditions are solved numerically using Fluent computational fluid dynamics code considering a single-step reaction kinetics model for methane–oxyfuel combustion. Comparison of both oxyfuel combustion and air–fuel combustion indicates that the temperature levels are reduced in oxyfuel combustion. The results show that the temperature levels are greatly reduced as the percentage of recirculated CO₂ is increased. It is concluded that the flame propagation speed in the CO₂ environment is lower than that in N₂. It is found that the natural gas and oxygen consumption rates are slower in oxyfuel combustion relative to air–fuel combustion. Heat transfer from the burnt gases to the water jacket along the different surfaces of the furnace is calculated. It is shown that the energy absorbed is much lower in the case of oxyfuel combustion along all surfaces except for the end part of the furnace close to the furnace rear wall. However, the same performance of the methane-oxy-flames is expected by increasing the oxygen concentration slightly above 29%.     

First-principles calculations of ground-state and high-pressure phase of magnesium telluride

We study the ground-state properties of MgTe and the behavior under pressure using the new full potential augmented plane wave plus local orbital method (FP-LAPW + lo) within the local spin density approximation (LSDA) to density functional theory. The calculations were performed in the rocksalt (B1), cesium chloride (B2), zincblende (B3), wurtzite (B4) and nickel arsenide (B8₁) type structures. Our calculations clearly indicate that there is a structural transition from the B8 to B2, confirming recent experimental suggestions and also show that the ground-state phase of MgTe is the nickel arsenide (B8₁) structure.     

Persistence of endodontic methacrylate-based cement residues on dentin adhesive surface treated with different chemical removal protocols

The aim of this study was to evaluate the persistence of methacrylate‐based cement residues on the dentin, after dentin surface cleaning with ethanol or acetone, with or without previous application of a dentin adhesive. Forty bovine crown fragments were obtained and the dentin surface was washed with 1.0 mL of 2.5% sodium hypochlorite (NaOCl), followed by 0.1 mL of 17% ethylenediaminetetraacetic acid application for 3 min, and final irrigation with 2.5% NaOCl. The specimens were air dried and resin‐based cement was rubbed onto the dentine surface with a microbrush applicator. In 20 specimens, previously to cement, a dentin adhesive was applied in all surfaces. After 15 min, the surface was scrubbed with a cotton pellet and moistened with ethanol or acetone, compounding the following groups: G1—99.5% ethanol and G2—acetone, without previous use of dentin adhesive; G3—99.5% ethanol and G4—acetone, with previous use of dentin adhesive. The dentin surface was scrubbed until the cement residues could not be visually detected. Sections were then processed for scanning electron microscopy and evaluated at 500× magnification and scores were attributed to each image according to the area covered by residual sealer, and data were subjected to Kruskal–Wallis at 5% significance. The lower residue presence was observed in G3 (P = 0.005). All surface presented cement residues when acetone was used as cleaning solution (P = 0.0005). The cleaning solutions were unable to completely remove the cement residues from both surfaces. The ethanol used after previous application of the dentin adhesive promoted the lower presence of residues. Microsc. Res. Tech. 2012. © 2012 Wiley Periodicals, Inc.