Investigation of Manufacturing Parameters on the Mechanical Properties of Powder Metallurgy Magnesium Matrix Nanocomposite by Artificial Neural Networks

In present study, Artificial Neural Network (ANN) approach to prediction of the ODS Magnesium matrix composite mechanical properties obtained was used. Several composition of Mg- Al2O3 composites with four different amount of Al2O3 reinforcement with four different size of nanometer to micrometer were produced in different sintering times. The specimens were characterized using metallographic observation, microhardness and strength (UTS) measurements. Then, for modeling and prediction of mentioned conditions, a multi layer perceptron back propagation feed forward neural network was constructed to evaluate and compare the experimental calculated data to predicted values. In neural network training modules, different composition, sintering time and reinforcement size were used as input (3 inputs), hardness and Ultimate Tensile Strength(UTS) were used as output. Then, the neural network was trained using the prepared training set. At the end of training process the test data were used to check the system’s accuracy. As a result, the comparison of neural network output results with the results from experiments and empirical relationship has shown good agreement with average error of 2.5%. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3511

Moyamoya Induced Acute Paraplegia in A Child with Epilepsy

ObjectiveMoyamoya disease (MMD) is a chronic, occlusive, cerebrovascular disorder of unknown  pathogenesis, characterized by progressive stenosis of the bilateral supraclinoid internal carotid arteries, with concomitant formation of tortuous arterial collateral vessels at the base of the brain, which reconstitute distal branches of the cerebral circulation. In Japanese, "Moyamoya" means "hazy puff of smoke" and refers to the angiographic appearance of the abnormal network of vessels that develop at the base of the brain and basal ganglia to supply a collateral route of blood flow. We report here the case of Moyamoya disease in a 5 year-old girl with normal mentality with a one year history of epilepsy, with Todd's paralysis. This condition is rare and most patients are diagnosed in childhood. With this report we aim to underscore the possibility that a usual neurological sign could be associated with unusual neurological disorders.

Oral health status, knowledge, attitude and practice of patients with heart disease

BACKGROUND: The aim of this study was to investigate knowledge, attitude and practice (KAP) of cardiovascular disease (CVD) patients about their oral health status. METHODS: In this cross-sectional study, we analyzed the data of 150 CVD patients that collected by a self-administered questionnaire consists of demographic characteristics and KAP. Oral health indicators calculated based on the results of oral examination by an expert dentist. RESULTS: CVD patients had an overall moderate level of knowledge and attitude, but their practice was lower than moderate. There were important associations between knowledge scores with gender, education, residential area and financial status, between attitude scores with education and residential area, and between practice scores with education and financial status. There were no associations between KAP and age, marital status or job. Significant positive correlations were found between KAP components. Significant negative correlations were found between oral hygiene index with knowledge and practice. CONCLUSION: The practice of heart disease patients about their oral health was poor, and declares that increasing awareness and attitude may not promote practice. Efficient programs are needed to promote oral health practice of adult populations in special groups. © 2016, Isfahan University of Medical Sciences(IUMS). All rights reserved

Increasing Ti-6Al-4V brazed joint strength equal to the base metal by Ti and Zr amorphous filler alloys

Microstructural features developed along with mechanical properties in furnace brazing of Ti-6Al-4V alloy using STEMET 1228 (Ti-26.8Zr-13Ni-13.9Cu, wt.%) and STEMET 1406 (Zr-9.7Ti-12.4Ni-11.2Cu, wt.%) amorphous filler alloys. Brazing temperatures employed were 900-950 °C for the titanium-based filler and 900-990 °C for the zirconium-based filler alloys, respectively. The brazing time durations were 600, 1200 and 1800 s. The brazed joints were evaluated by ultrasonic test, and their microstructures and phase constitutions analyzed by metallography, scanning electron microscopy and X-ray diffraction analysis. Since microstructural evolution across the furnace brazed joints primarily depends on their alloying elements such as Cu, Ni and Zr along the joint. Accordingly, existence of Zr 2Cu, Ti 2Cu and (Ti,Zr) 2Ni intermetallic compounds was identified in the brazed joints. The chemical composition of segregation region in the center of brazed joints was identical to virgin filler alloy content which greatly deteriorated the shear strength of the joints. Adequate brazing time (1800 s) and/or temperature (950 °C for Ti-based and 990 °C for Zr-based) resulted in an acicular Widmanstätten microstructure throughout the entire joint section due to eutectoid reaction. This microstructure increased the shear strength of the brazed joints up to the Ti-6Al-4V tensile strength level. Consequently, Ti-6Al-4V can be furnace brazed by Ti and Zr base foils produced excellent joint strengths. © 2012 Elsevier Inc. All rights reserved

Investigation on braze joint strength and microstructure of Ti-CP with Ag and Ti base filler alloys

This research investigates influences of brazing parameters (brazing alloy, temperature and time) on microstructures and mechanical properties of a commercially pure (CP) titanium sheet which is brazed with CBS 34 (Ag-based) and STEMET 1228 (Ti-based) braze-filler foils. Brazing was performed in a conventional inert furnace at temperature ranges of 800-870°C and 10-30 minutes for holding times. Qualities of the brazed joints were evaluated by ultrasonic testing, and then, microstructure and phase constitution of the bonded joints were analyzed by means of metallography, scanning electron microscope (SEM), and X-ray diffraction (XRD). Mechanical properties of brazed joints were evaluated by shear testing. Diffusion of titanium from substrate to filler alloy developed a strong reaction between them. A number of phases such as TiCu, Ti 2Cu, TiAg, Ag-Zn solid solution matrix (for Ag-based brazed samples) and Ti 2Cu, (Ti,Zr) 2Ni, Zr 2Cu (for Ti-based brazed samples) have been identified. The optimum brazing parameters were achieved at a temperature of 870 °C-20 min for CBS 34 and 870 °C-30 min for STEMET 1228. The specimen using STEMET 1228 braze alloy demonstrates best bonding strength (equal to Ti-CP tensile strength). Copyright 2012 ASM International® All rights reserved

Evaluate of braze joint strength and microstructure characterize of titanium-CP with Ag-based filler alloy

This research investigates the influences of brazing parameters (temperature and time) on microstructures and the mechanical properties of commercially pure (CP) titanium sheet when it is brazed with CBS34 (Ag-20Cu-22Zn-24Cd) braze filler foil. Brazing was performed in a conventional atmosphere control furnace. The brazing temperatures and holding times employed in this study were 800-870°C and 10-20min, respectively. The qualities of the brazed joints were evaluated by ultrasonic test and the microstructure and phase constitution of the bonded joints were analyzed by means of metallography, scanning electron microscope (SEM) and X-ray diffraction (XRD). The mechanical properties of brazed joints were evaluated by microhardness and shear tests. The diffusion between Ti, Ag, Cu, Zn and Cd from substrate and braze alloy, developed a strong reaction between each other. A number of intermetallic phases, such as TiCu and Ti2Cu in the Ag-Zn solid solution matrix have been identified especially at 870°C - 20min. Both the brazing temperature and the holding time are critical factors for controlling the microstructure and hence the mechanical properties of the brazed joints. The optimum brazing parameters was achieved at 870°C - 20min. Based on the shear test result, all cracks propagate along the brittle intermetallic compounds like Ti2Cu in the reaction layer which typically are composed of quasi-cleavage (Ag-Zn matrix) and brittle appearance. © 2012 Elsevier Ltd

Bridged Carbon Fabric Membrane with Boosted Performance in AC Line Filtering Capacitors

High frequency responsive capacitors with lightweight, flexibility, and miniaturization are among the most vital circuit components because they can be readily incorporated into various portable devices to smooth out the ripples for circuits. Electrode materials no doubt are at the heart of such devices. Despite tremendous efforts and recent advances, the development of flexible and scalable high frequency responsive capacitor electrodes with superior performance remains a great challenge. Herein, a straightforward and technologically relevant method is reported to manufacture a carbon fabric membrane glued by nitrogen doped nanoporous carbons produced through a polyelectrolyte complexation induced phase separation strategy. The as obtained flexible carbon fabric bearing a unique hierarchical porous structure, and high conductivity as well as robust mechanical properties, serves as the free standing electrode materials of electrochemical capacitors. It delivers an ultrahigh specific areal capacitance of 2632 F cm amp; 8722;2 at 120 Hz with an excellent alternating current line filtering performance, fairly higher than the state of the art commercial ones. Together, this system offers the potential electrode material to be scaled up for AC line filtering capacitors at industrial level

All-optical switching in granular ferromagnets caused by magnetic circular dichroism

Magnetic recording using circularly polarised femto-second laser pulses is an emerging technology that would allow write speeds much faster than existing field driven methods. However, the mechanism that drives the magnetisation switching in ferromagnets is unclear. Recent theories suggest that the interaction of the light with the magnetised media induces an opto-magnetic field within the media, known as the inverse Faraday effect. Here we show that an alternative mechanism, driven by thermal excitation over the anisotropy energy barrier and a difference in the energy absorption depending on polarisation, can create a net magnetisation over a series of laser pulses in an ensemble of single domain grains. Only a small difference in the absorption is required to reach magnetisation levels observed experimentally and the model does not preclude the role of the inverse Faraday effect but removes the necessity that the opto-magnetic field is 10 s of Tesla in strength

Magnetisation switching of FePt nanoparticle recording medium by femtosecond laser pulses

Manipulation of magnetisation with ultrashort laser pulses is promising for information storage device applications. The dynamics of the magnetisation response depends on the energy transfer from the photons to the spins during the initial laser excitation. A material of special interest for magnetic storage are FePt nanoparticles, for which switching of the magnetisation with optical angular momentum was demonstrated recently. The mechanism remained unclear. Here we investigate experimentally and theoretically the all-optical switching of FePt nanoparticles. We show that the magnetisation switching is a stochastic process. We develop a complete multiscale model which allows us to optimize the number of laser shots needed to switch the magnetisation of high anisotropy FePt nanoparticles in our experiments. We conclude that only angular momentum induced optically by the inverse Faraday effect will provide switching with one single femtosecond laser pulse.EC under Contract No. 281043, FemtoSpin. The work at Greifswald University was supported by the German research foundation (DFG), projects MU MU 1780/8-1, MU 1780/10-1. Research at Göttingen University was supported via SFB 1073, Projects A2 and B1. Research at Uppsala University was supported by the Swedish Research Council (VR), the Röntgen-Ångström Cluster, the Knut and Alice Wallenberg Foundation (Contract No. 2015.0060), and Swedish National Infrastructure for Computing (SNIC). Research at Kiel University was supported by the DFG, projects MC 9/9-2, MC 9/10-2. P.N. acknowledges support from EU Horizon 2020 Framework Programme for Research and Innovation (2014-2020) under Grant Agreement No. 686056, NOVAMAG. The work in Konstanz was supported via the Center for Applied Photonics