Convolutional neural networks for the classification of chest X-rays in the IoT era

Multimedia Tools and Applications - Chest X-ray medical imaging technology allows the diagnosis of many lung diseases. It is known that this technology is frequently used in hospitals, and it is...     

Effect of surface treatment on electrical conductivity of carbon black filled conductive polymer composites

Two different types of surface modifiers, 3‐aminopropyltriethoxysilane and formamide, were applied to carbon black (CB) particles to lower electrical resistivity of polymer composites prepared by treated CB. Two different matrices, low‐density polyethylene and nylon 6, were chosen to compound with surface modified CB. Surface energy of CB was increased by adding amine or amide functional groups during surface treatment of CB. According to electron spectroscopy for chemical analysis (ESCA), chemical modification in surface chemistry of CB was obtained with the chemicals used for the treatment due to the nitrogen atoms in their structures, which may act as dopant atom. As a result of this, electrical resistivity of composites prepared by treated CB decreased. In addition, there was not any significant change in tensile strength and tensile modulus of the composites with the surface treatment. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Effect of composite preparation techniques on electrical and mechanical properties and morphology of nylon 6 based conductive polymer composites

Nylon 6/carbon black conductive composites were prepared using two different methods, masterbatch dilution and melt mixing. Their effect on the size and distribution of carbon black agglomerates in the matrix was studied in terms of electrical and mechanical properties and morphology. The electrical resistivity of composites prepared by both methods decreased with increasing filler composition. The electrical resistivity of the diluted masterbatch composites and the melt mixed composites was reduced from the resistivity of pure nylon 6, 10¹⁵ “ohm, cm”, to 10⁷ “ohm, cm” at 1 and 6 wt % of carbon black, respectively. As the filler content increased, elongation at break and impact strength decreased, but tensile modulus increased. Masterbatch dilution method provided smaller carbon black clusters in composites compared to melt mixing method. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2520–2526, 2006     

Effect of solid state grinding on properties of PP/PET blends and their composites with carbon nanotubes

In this study, it was aimed to improve electrical conductivity and mechanical properties of conductive polymer composites, composed of polypropylene (PP), poly(ethylene terephthalate) (PET), and carbon nanotubes (CNT). Grinding, a type of solid state processing technique, was applied to PP/PET and PP/PET/CNT systems to reduce average domain size of blend phases and to improve interfacial adhesion between these phases. Surface energy measurements showed that carbon nanotubes might be selectively localized at PET phase of immiscible blend systems. Grinding technique exhibited improvement in electrical conductivity and mechanical properties of PP/PET/CNT systems at low PET compositions. Ground composites molded below the melting temperature of PET exhibited higher tensile strength and modulus values than those prepared above the melting temperature of PET. According to SEM micrographs, micron‐sized domain structures were obtained with ground composite systems in which PET was the minor phase. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Improving reinforcement learning by using sequence trees

This paper proposes a novel approach to discover options in the form of stochastic conditionally terminating sequences; it shows how such sequences can be integrated into the reinforcement learning framework to improve the learning performance. The method utilizes stored histories of possible optimal policies and constructs a specialized tree structure during the learning process. The constructed tree facilitates the process of identifying frequently used action sequences together with states that are visited during the execution of such sequences. The tree is constantly updated and used to implicitly run corresponding options. The effectiveness of the method is demonstrated empirically by conducting extensive experiments on various domains with different properties.     

A novel strategy for cartilage tissue engineering: Collagenase-loaded cryogel scaffolds in a sheep model

In this study, we developed a novel strategy, through which cartilage tissue pieces were placed in a sheep cartilage defect model and covered with a collagenase incorporated cryogel scaffold (in vivo cartilage tissue engineering, IVCTE group). While applying this strategy, the chondrocytes could be isolated inside the body and the treatment could be accomplished in one session. To compare our strategy, to another group, in which we used cultured cells and Chondro-gide, standard matrix-induced autologous chondrocyte implantation (MACI) was applied. Although the MACI applied group demonstrated better healing than IVCTE, the type II collagen synthesis was better in the IVCTE group compared to MACI applied group. Collagenase did not have detrimental effect on surrounding cartilage in IVCTE group. The preliminary results of the novel strategy applied group (IVCTE) were promising.     

Poly(ethylene terephthalate)/carbon nanotube composites prepared with chemically treated carbon nanotubes

Surfaces of multiwalled carbon nanotubes (CNT) were functionalized by treatment with strong acid mixture (purification) followed by modification with sodium dodecyl sulfate, poly(ethylene glycol) (PEG), and diglycidyl ether of Bisphenol A (DGEBA). Poly(ethylene terephthalate) (PET)‐based conductive polymer composites were prepared by using these CNT by means of melt mixing with a twin screw extruder. Amount of carboxylic acid groups on the CNT surface increased after acid treatment but decreased with surface modification due to the consumption of these groups during the chemical reactions between the surface modifiers and CNT surface. Fourier transformed infrared spectroscopy (FTIR) and nuclear magnetic resonance analyses of the composites revealed the increase in the interactions between PET and CNT surface after treatment with PEG and DGEBA. Mechanical strength of the composites prepared with modified CNT were higher than that of the untreated CNT‐filled composite owing to the enhanced interactions between PET and CNT. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers     

Effect of carbon nanotube purification on the electrical and mechanical properties of poly(ethylene terephthalate) composites with carbon nanotubes in low concentration

Surface properties of carbon nanotubes (CNTs) were altered by purification with nitric acid, sulfuric acid, ammonium hydroxide, and hydrogen peroxide. As‐received and purified CNT‐based conductive poly (ethylene terephthalate) composites were prepared with a twin‐screw extruder. The effects of CNT purification on the surface properties of the CNTs and on the morphology and electrical and mechanical properties of CNT‐based composites were investigated. Surface energy measurements showed that the acidic component of the surface energies of the CNTs increased after purification. According to Fourier transform infrared (FTIR) spectroscopy, the purification resulted in the formation of oxygen‐containing functional groups on the surfaces of the CNTs. Electron spectroscopy for chemical analysis results indicate the removal of the metallic catalyst residues and an increase in the oxygen content of the CNT surfaces as a result of the purification procedure. X‐ray diffraction analyses revealed a change in the crystalline structure of the CNTs after purification. All of the composites prepared with the purified CNTs had higher electrical resistivities and tensile and impact strength values than the composites based on the as‐received CNTs because of the functional groups and defect sites formed on the surfaces of the CNTs during purification. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Impact damage sensing of multiscale composites through epoxy matrix containing carbon nanotubes

Carbon nanotubes are used to provide increased electrical conductivity for polymer matrix materials, thus offering a method to monitor the structure's health. This work investigates the effect of impact damage on the electrical properties of multiscale composite samples, prepared with woven fiberglass reinforcement and epoxy resin modified with as‐received multi‐walled carbon nanotubes (MWCNTs). Moreover, this study addresses potential bias from manufacturing, and investigates the effectiveness of resistance measurements using two‐ and four‐point probe methods. Transmission electron microscopy and static tensile tests results were used to evaluate, respectively, the dispersion of MWCNTs in the epoxy resin and the influence of the incorporation of these nanoparticles on the static tensile properties of the matrix, and interpret results from the resistance measurements on impacted specimens. In this study, the four‐point probe method is shown to be much more repeatable and reliable than the two‐point probe method. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Production of AgCu:NiO/Ni foam electrode with high charge accumulation and long cycling stability

Nickel oxide is a promising material for electrochemical energy storage devices due to its high specific surface area, rapid redox reactions, and short diffusion path in the solid electrode. It has been known that the loading of metallic elements into the NiO matrix enhances these superior properties. NiO material is electrochemically deposited on Ni foam, and then, Ag and Cu thin layers are coated on NiO by thermal evaporation. The produced NiO/Ni foam and AgCu:NiO/Ni foam electrodes are annealed at 400 °C for 1 h. Those are utilized as anode for high-performance energy storage electrode in an alkaline solution. The former has an energy density of 56.9 Wh kg^?1 at 3155.5 W kg^?1, while the latter has a high energy density of 107.6 Wh kg^?1 at the corresponding power density of 2957.7 W kg^?1. Although specific capacitance of the former decreases to 46.2% of its original capacitance at 10 A g^?1 after 5000 cycles, the latter exhibits higher cycling stability with 71.0% retention after 5000 charge–discharge cycles owing to the loading of Ag and Cu into NiO matrix. Charge transfer resistance of NiO/Ni foam, which is inversely proportional to electroactive surface area, reduces from 19.4 to 0.28 Ω after the incorporation of Ag and Cu. Compared to NiO/Ni foam, AgCu:NiO/Ni foam with a higher electroactive surface area is more appropriate for charge accumulation. As mention above, the features of AgCu:NiO/Ni foam indicate that it is a promising material as an effective start-of-art energy storage device.