A New Method For Digital Watermarking Based on Combination of DCT and PCA

In the digital watermarking with DCT method,the watermark is located within a range of DCT coefficients of the cover image. In this paper to use the low-frequency band, a new method is proposed by using a combination of the DCT and PCA transform. The proposed method is compared to other DCT methods, our method is robust and keeps the quality of cover image, also increases capacity of the watermarking.Comment: Telecommunications Forum Telfor (TELFOR), 2014 22n

Does soy protein supplementation affect body composition in healthy exerciser adults? A systematic review and meta-analysis of clinical trials

Background objectives: The effects of soy protein supplementation on anthropometric parameters and body composition indices of healthy adults is equivocal. The aims of this systematic review and meta-analysis were to assess the effects of soy protein supplementation on weight and body composition of healthy adults in clinical trial studies. Methods: A systematic search of literature was carried out on clinical trial studies in PubMed, Scopus, Cochrane's library and ISI Web of Science Direct up until November 2017. From 492 studies initially retrieved, only 8 articles with 6, 5 and 4 arms included in the meta-analysis of the effects of soy protein supplementation on body weight, Fat free mass and Fat mass, respectively, with 120 participants in the intervention group and 119 participants in the control group. Results: Results of the fixed effect model meta-analysis showed that soy protein supplementation had no significant effects on body weight (0.94 kg, 95 CI: �2.41, 4.30 kg; P = 0.58), fat-free mass (0.6 kg, 95 CI: �0.21, 1.41; P = 0.14) or fat mass (0.43 kg, 95 CI: �2.18, 3.03; P = 0.74) in healthy exercising adults. Conclusions: Results of this meta-analysis study does not confirm any significant beneficial effects of soy protein supplementation on weight and body composition in healthy adults. © 201

Multiple Sclerosis in Children: A Review of Clinical and Paraclinical Features in 26 Cases

ObjectiveMultiple sclerosis (MS) is an inflammatory demyelinating disease of central nervous system (CNS) that is increasingly being recognized as a disease affecting children. However, the clinical features of childhood MS at onset have been rarely reported from Asia.Materials & MethodsThis report presents a retrospective chart review of 26 patients with MS (20 females and 6 males), with an onset age of MS of less than 16 years, in the south of Iran between March 2001and November 2007; it documents researchers' experiencesResultsFemale/male ratio was 3:1. Mean age in females was higher than males (13 vs.12.16).The disease was highly variable in onset presentation; the most common initial symptoms were limb weakness, disequilibrium, and diplopia. Three patients had a positive family history of MS in their first degree relatives. VEP was abnormal in 9 of 19(47%). MRI demonstrated multiple plaques in the brain in 24(92%) cases. Relapse remitting MS was a dominant pattern noticed in 23(88%) cases.ConclusionMS, in childhood, is not as rare as commonly believed; although its diagnosis is essentially a clinical one, paraclinical investigations are of great value in the identification of demyelinating disorders in childhood. The disease, as it occurs in children, does not appear to differ clinically from the disease as observed in adults. If pediatricians should confront a child showing evidence of scatteredneurological deficits that remit, particularly weakness, disturbance of vision and co-ordination, they need to consider the possibility of MS. 

Fabrication and characterization of the modified ev31-based metal matrix nanocomposites

Metal matrix nanocomposites (MMNCs) with high specific strength have been of interest for numerous researchers. In the current study, Mg matrix nanocomposites reinforced with AlN nanoparticles were produced using the mechanical stirring-assisted casting method. Microstructure, hardness, physical, thermal and electrical properties of the produced composites were characterized in this work. According to the microstructural evaluations, the ceramic nanoparticles were uniformly dispersed within the matrix by applying a mechanical stirring. At higher AlN contents, however, some agglomerates were observed as a consequence of a particle-pushing mechanism during the solidification. Microhardness results showed a slight improvement in the mechanical strength of the nanocomposites following the addition of AlN nanoparticles. Interestingly, nanocomposite samples were featured with higher electrical and thermal conductivities, which can be attributed to the structural effect of nanoparticles within the matrix. Moreover, thermal expansion analysis of the nanocomposites indicated that the presence of nanoparticles lowered the Coefficient of Thermal Expansion (CTE) in the case of nanocomposites. All in all, this combination of properties, including high mechanical strength, thermal and electrical conductivity, together with low CTE, make these new nanocomposites very promising materials for electro packaging applications

Comparative insight into the interfacial phase evolutions during solution treatment of dissimilar friction stir welded AA2198-AA7475 and AA2198-AA6013 aluminum sheets

In the current research, dissimilar friction stir welded (FSW) sheets of AA2198-AA7475 and AA2198-AA6013 were solution treated at 460–580◦C for 1 h. Annealing at 580◦C led to complete degradation of both dissimilar weldments from the AA2198 side. According to the microstructure inspection, solution treatment triggered abnormal grain growth within the stir zone (SZ), and applying higher treatment temperatures enhanced the fraction of transformed grains. SEM analysis revealed that the pre-melting of grain boundaries (GBs) over 540◦C encouraged the diffusion of solute atoms to the GBs. The massive diffusion of Cu to the GBs led to the formation of Cu-rich eutectic phases in AA7475 and AA2198 and dense Cu-rich particles in AA6013. In the meantime, the diffusion of Mg and Zn to the GBs of AA7475 and Fe and Si to the GBs of AA6013 eventuated in the formation of coarse particles at the GBs which, in return, attenuated the bonding adhesion of the grains at SZ. The formation of remarkable Cu-rich phases in the pre-melted regions and significant contraction of the eutectic phase while cooling as well as the formation of particles at GBs resulted in intergranular failure of the joints from the AA2198 side of the SZ

Tribological behaviour of AZ31 magnesium alloy reinforced by bimodal size B4C after precipitation hardening

This study investigated dry sliding wear properties of AZ31 magnesium alloy and B4C-reinforced AZ31 composites containing 5, 10, and 20 wt.% B4C with bimodal sizes under different loadings (10–80 N) at various sliding speeds (0.1–1 m/s) via the pin-on-disc configuration. Microhardness evaluations showed that when the distribution of B4C particles was uniform the hardness of the composites increased by enhancing the reinforcement content. The unreinforced alloy and the composite samples were examined to determine the wear mechanism maps and identify the dominant wear mechanisms in each wear condition and reinforcement content. For this purpose, wear rates and friction coefficients were recorded during the wear tests and worn surfaces were characterized by scanning electron microscopy and energy dispersive X-ray spectrometry analyses. The determined wear mechanisms were abrasion, oxidation, delamination, adhesion, and plastic deformation as a result of thermal softening and melting. The wear evaluations revealed that the composites containing 5 and 10 wt.% B4C had a significantly higher wear resistance in all the conditions. However, 20 wt.% B4C/AZ31 composite had a lower resistance at high sliding speeds (0.5–1 m/s) and high loadings (40–80 N) in comparison with the unreinforced alloy. The highest wear resistance was obtained at high sliding speeds and low loadings with the domination of oxidative wear

Hot deformation behavior and flow stress modeling of Ti–6Al–4V alloy produced via electron beam melting additive manufacturing technology in single β-phase field

The hot working behaviour of additively manufactured Ti–6Al–4V pre-forms by Electron Beam Melting (EBM) has been studied at temperatures of 1000–1200 °C and strain rates of 0.001–1 s−1. As a reference, a wrought Ti–6Al–4V alloy was also analyzed as same as the EBM one. In order to investigate the hot working behaviour of these samples, all the data evaluations were carried out step by step, and the stepwise procedure was discussed. No localized strain as a consequence of shear band formation was found in the samples after the hot compression. The flow stress curves of all the samples showed peak stress at low strains, followed by a regime of flow softening with a near-steady-state flow at large strains. Interestingly, it is found that the initial microstructure and porosity content as well as the chemistry of material (e.g. oxygen content) as being possible contributors to the lower level of flow stress that could be beneficial from the industrial point of view. The flow softening mechanism(s) were discussed in detail using the microstructure of the specimens before and after the hot deformation. Dynamic Recrystalization (DRX) could also explain the gentle oscillation in the appearance of the flow softening curves of the EBM samples. Moreover, the hot working analysis indicated that the activation energy for hot deformation of as-built EBM Ti–6Al–4V alloy was calculated as ~193.25 kJ/mol, which was much lower than the wrought alloy (229.34 kJ/mol). These findings can shed lights on a new integration of metal Additive Manufacturing (AM) and thermomechanical processing. It is very interesting to highlight that through this new integration, it would be possible to reduce the forging steps and save more energy and materials with respect to the conventional routes

Report of Erythraeus (Erythraeus) adanaensis (Acari: Prostigmata: Erythraeidae) from Iran

Based on a study on the Parasitengona mite fauna of East Azarbaijan province (Iran) accomplished in 2007 and 2008, several specimens were collected. Among them, Erythraeus (Erythraeus) adanaensis Saboori & Cobanoglu, 2010 is getting reported for the first time from Iran