bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hardness and Microstructure of Mixed Al-CNF Powder Extrusion
Authors: Kim D.-H. , Kim T.-J. , Lim S.-G. 
Published: July 2017

AbstractIn this study, mechanical properties and microstructures of extruded aluminum matrix composites were investigated. The composite materials were manufactured by two step methods: powder metallurgy (mixture of aluminum powder and carbon fiber using a turbular mixer, pressing of mixed aluminum powder and carbon fiber using a cold isostatic pressing) and hot extrusion of pressed aluminum powder and carbon fiber. For the mixing of Al powder and carbon fibers, aluminum powder was used as a powder with an average particle size of 30 micrometer and the addition of the carbon fibers was 50% of volume. In order to make mixing easier, it was mixed under an optimal condition of turbular mixer with a rotational speed of 60 rpm and time of 1800s. The process of the hot-extrusion was heated at 450°C for 1 hour. Then, it was hot-extruded with a condition of extrusion ratio of 19 and ram speed of 2 mm/s. The microstructural analysis of extruded aluminum matrix composites bars and semi-solid casted alloys were carried out with the optical microscope, scanning electron microscope and X-ray diffraction. Its mechanical properties were evaluated by Vickers hardness and tensile test.
Surface Modification of Self-Consolidated Microporous Ti Implant Compacts Fabricated by Electro-Discharge-Sintering in Air
Authors: Jo Y.J. , Yoon Y.H. , Kim Y.H. , Chang S.Y. , Kim J.Y. , Lee Y.K. , Van Tyne C.J. , Lee W.H. 
Published: July 2017

AbstractA single pulse of 0.75-2.0 kJ/0.7g of atomized spherical Ti powders from 300 mF capacitor was applied to produce a microporous Ti implant compact by electro-discharge-sintering (EDS). A solid core in the middle of the compact surrounded by a microporous layer was found. X-ray photoelectron spectroscopy was employed to study the surface characteristics of the EDS Ti compact and it revealed that Ti, C and O were the main constituents on the surface with a smaller amount of N. The surface was lightly oxidized and was primarily in the form of TiO2resulting from the air oxidation during EDS processing. The lightly oxidized surface of the EDS compact also exhibited Ti nitrides such as TiN and TiON, which revealed that the reaction between air constituents and the Ti powders even in times as short as 128 msec.
Self-Consolidation and Surface Modification of Mechanical Alloyed Ti-25.0 at.% Al Powder Mixture by Using an Electro-Discharge Technique
Authors: Chang S.Y. , Jang H.S. , Yoon Y.H. , Kim Y.H. , Kim J.Y. , Lee Y.K. , Lee W.H. 
Published: July 2017

AbstractElectrical discharges using a capacitance of 450 μF at 0.5, 1.0, and 1.5 kJ input energies were applied in a N2atmosphere to obtain the mechanical alloyed Ti3Al powder without applying any external pressure. A solid bulk of nanostructured Ti3Al was obtained as short as 160 μsec by the Electrical discharge. At the same time, the surface has been modified into the form of Ti and Al nitrides due to the diffusion process of nitrogen to the surface. The input energy was found to be the most important parameter to affect the formation of a solid core and surface chemistry of the compact.
Thermal Conductivity and Microstructure of Copper Coated Graphite Composite by Spark Plasma Sintering Process
Authors: Park S.H. , Kim D.B. , Lee R.G. , Son I.J. 
Published: July 2017

AbstractThis study focuses on the fabrication of thermal management material for power electronics applications using graphite flake reinforced copper composites. The manufacturing route involved electroless plating of copper in the graphite flake and sintering process are optimized. The microstructures, interface, thermal properties, and relative density of graphite/Cu composites are investigated. The relative density of the composites shows 99.5% after sintering. Thermal conductivities and coefficients of thermal expansion of this composites were 400-480 Wm−1K−1and 8 to 5 ppm k−1, respectively. Obtained graphite nanoplatelets-reinforced composites exhibit excellent thermo-physical properties to meet the heat dispersion and matching requirements of power electronic devices to the packaging materials.
Copper-Carbon Nanoforms Composites – Processing, Microstructure and Thermal Properties
Authors: Pietrzak K. , Gładki A. , Frydman K. , Wójcik-Grzybek D. , Strojny-Nędza A. , Wejrzanowski T. 
Published: July 2017

AbstractThe main current of publication is focused around the issues and problems associated with the formation of composite materials with Cu matrix and reinforcing phases in the various carbon nanoforms. The core of the research has been focused on thermal conductivity of these composites types. This parameter globally reflects the state of the structure, quality of raw materials and the technology used during the formation of composite materials. Vanishingly low affinity of copper for carbon, multilayered forms of graphene, the existence of critical values of graphene volume in the composite are not conducive to the classic procedures of composites designing. As a result, the expected, significant increase in thermal conductivity of composites is not greater than for pure copper matrix. Present paper especially includes: (i) data of obtaining procedure of copper/graphene mixtures, (ii) data of sintering process, (iii) the results of structure investigations and of thermal properties. Structural analysis revealed the homogenous distribution of graphene in copper matrix, the thermal analysis indicate the existence of carbon phase critical concentration, where improvement of thermal diffusivity to pure copper can occur.
Investigations of Interface Properties in Copper-Silicon Carbide Composites
Authors: Chmielewski M. , Pietrzak K. , Strojny-Nędza A. , Jarząbek D. , Nosewicz S. 
Published: July 2017

AbstractThis paper analyses the technological aspects of the interface formation in the copper-silicon carbide composite and its effect on the material’s microstructure and properties. Cu-SiC composites with two different volume content of ceramic reinforcement were fabricated by hot pressing (HP) and spark plasma sintering (SPS) technique. In order to protect SiC surface from its decomposition, the powder was coated with a thin tungsten layer using plasma vapour deposition (PVD) method. Microstructural analyses provided by scanning electron microscopy revealed the significant differences at metal-ceramic interface. Adhesion force and fracture strength of the interface between SiC particles and copper matrix were measured. Thermal conductivity of composites was determined using laser flash method. The obtained results are discussed with reference to changes in the area of metal-ceramic boundary.
A Study on Changes in Thickness of STS304 Material in the Progressive Drawing Process
Authors: Lee C.K. , Kim Y.C. 
Published: July 2017

AbstractIn the drawing process, the roundness of corners in the punch and the die are very important factors in determining the thicknesses of the product. The results clearly revealed that the thickness of a flange was increased and the thickness of body parts reduced when the roundness of the die entrance was small. The material thickness of the top part was decreased when the corner roundness of the punch was large. The smooth inflow of materials was found to have a significant effect on the thickness during the post-process. The compressive strength of STS 304 material exhibited a higher value compared with other processing methods. Moreover, we clearly observed the corner roundness of the punch and the die to be a very important factor for STS 304 materials.
Improvement of Microwave Absorbance of Polymer Composites of W-Type Hexaferrite Powders by Attachment of Frequency Selective Surface
Authors: Cho H.-S. , Kim S.-S. 
Published: July 2017

AbstractThis work investigates the effect of a frequency selective surface (FSS) composed of a regular array of square loop elements on the absorption properties of grounded ferrite composites. Polymer matrix composites of CoZnW hexaferrite powders having small magnetic loss were used as the substrate material. Computational tools were used to model the interaction between electromagnetic waves and materials and determine the reflection coefficient. Reflection loss and bandwidth were greatly improved by attaching an FSS with controlled electrical resistance (R) onto the grounded ferrite composites. For the FSS withR= 800 Ω, the minimum reflection loss decreased to −25 dB at 10 GHz and the bandwidth was broadened to 7.5-12.5 GHz with respect to −10 dB reflection loss.
Effect of Heat Treatment on the Microstructure and Tensile Deformation Behavior of Oxide Dispersion Strengthened Alloys Manufactured by Complex Milling Process
Authors: Kim Y.-K. , Kim J.-H. , Gwon J.-H. , Lee K.-A. 
Published: July 2017

Abstract
This study attempted to manufacture an ODS alloy by combining multiple milling processes in mechanical alloying stage to achieve high strength and fracture elongation. The complex milling process of this study conducted planetary ball milling, cryogenic ball milling and drum ball milling in sequential order, and then the microstructure and tensile deformation behavior were investigated after additional heat treatment. The oxide particles distributed within the microstructure were fine oxide particles of 5~20 nm and coarse oxide particles of 100~200 nm, and the oxide particles were confirmed to be composed of Cr, Ti, Y and O. Results of tensile tests at room temperature measured yield strength, tensile strength and elongation as 1320 MPa, 2245 MPa and 4.2%, respectively, before heat treatment, and 1161 MPa, 2020 MPa and 5.5% after heat treatment. This results indicate that the ODS alloy of this study gained very high strengths compared to other known ODS alloys, allowing greater plastic zones.
High Temperature Oxidation Property of SiC Coating Layer Fabricated by Aerosol Deposition Process
Authors: Ham G.-S. , Kim S.-H. , Park J.-Y. , Lee K.-A. 
Published: July 2017

AbstractThis study investigated the high temperature oxidation property of SiC coated layer fabricated by aerosol deposition process. SiC coated layer could be successfully manufactured by using pure SiC powders and aerosol deposition on the Zr based alloy in an optimal process condition. The thickness of manufactured SiC coated layer was measured about 5 μm, and coating layer represented high density structure. SiC coated layer consisted ofα-SiC andβ-SiC phases, the same as the initial powder. The initial powder was shown to have been crushed to the extent and was deposited in the form of extremely fine particles. To examine the high temperature oxidation properties, oxidized weight gain was obtained for one hour at 1000°C by using TGA. The SiC coated layer showed superior oxidation resistance property than that of Zr alloy (substrate). The high temperature oxidation mechanism of SiC coated layer on Zr alloy was suggested. And then, the application of aerosol deposited SiC coated layer was also discussed.
Torsion Property of the Structure Bonded Aluminum Foam Due to Impact
Authors: Hwang G.W. , Cho J.U. 
Published: July 2017

AbstractAn aluminum foam added with foaming agent, is classified into an open-cell type for heat transfer and a closed-cell type for shock absorption. This study investigates the characteristic on the torsion of aluminum foam for a closed-cell type under impact. The fracture characteristics are investigated through the composite of five types of aluminum foam (the thicknesses of 25, 35, 45, 55 and 65 mm), when applying the torsional moment of impact energy on the junction of a porous structure attached by an adhesive. When applying the impact energy of 100, 200 and 300J, the aluminum foams with thicknesses of 25 mm and 35 mm broke off under all conditions. For the energy over 200J, aluminums thicker than 55 mm continued to be attached. Furthermore, the aluminum specimens with thicknesses of 55 mm and 65 mm that were attached with more than 30% of bonding interface remained, proving that they could maintain bonding interface against impact energy. By comparing the data based on the analysis and test result, an increase in the thickness of specimen leads to the plastic deformation as the stress at the top and bottom of bonding interface moves to the middle by spreading the stress horizontally. Based on this fracture characteristic, this study can provide the data on the destruction and separation of bonding interface and may contribute to the safety design.
Fabrication and Shape Memory Characteristics of Highly Porous Ti-Nb-Mo Biomaterials
Authors: Kim Y.-W. , Mukarati T.W. 
Published: July 2017

AbstractNon-toxic Ti-Nb-Mo scaffolds were fabricated by sintering rapidly solidified alloy fibers for biomedical applications. Microstructure and martensitic transformation behaviors of the porous scaffolds were investigated by means of differential scanning calorimetric and X-ray diffraction. Theα″–βtransformation occurs in the as-solidified fiber and the sintered scaffolds. According to the compressive test of the sintered scaffolds with 75% porosity, they exhibit good superelasticity and strain recovery ascribed to the stress-induced martensitic transformation and the shape memory effect. Because of the high porosity of the scaffolds, an elastic modulus of 1.4 GPa, which matches well with that of cancellous bone, could be obtained. The austenite transformation finishing temperature of 77Ti-18Nb-5Mo alloy scaffolds is 5.1°C which is well below the human body temperature, and then all mechanical properties and shape memory effect of the porous 77Ti-18Nb-5Mo scaffolds are applicable for bon replacement implants.
Collection of Industrial Oil Using Nanoparticles and Porous Powders of Silica
Authors: Cho Y.-S. , Moon J.-W. 
Published: July 2017

AbstractIndustrial oil was collected using hydrophobic silica powders. Silica nanopowder was modified with octadecyltriethoxysilane (OTS) using spray pyrolysis reactor continuously. Besides nanoparticles, mesoporous silica powder synthesized using Pluronic P104 was adopted as another oil adsorbents. Spherical macroporous or meso-macroporous silica particles were prepared by self-assembly for the removal of oil. The effects of the amount of powder on the oil adsorption were studied and compared with the results of various silica powders. The meso-macroporous silica particles were found to be the most efficient, indicating that both specific surface area and porosity played crucial role.
Control of Natural Zeolite Properties by Mechanical Activation in Stirred Media Mill
Authors: Bohács K. , Faitli J. , Bokányi L. , Mucsi G. 
Published: July 2017

AbstractDue to the special characteristics of zeolites, they can be applied in a very wide range of industries, i.e. agricultural, environmental or water treatment purposes. Generally, high added value zeolite products are manufactured by micro- or nanogrinding. However, these processes require high energy input and cause significant wearing of the mill parts. Therefore, the optimization of zeolite grinding, as well as the control of its properties are of a great importance. In the present paper a Hungarian natural zeolite was mechanically activated in stirred media mill for various residence times in distilled water, meanwhile the particle size distribution and the grinding energy were measured. Additionally, on-line tube rheometer was used to study the rheology of the suspension during the grinding process. The particle interaction and the suspension aggregation stability were detected by zeta-potential measurements. Structural changes due to the mechanical activation process were monitored by FTIR. It was found that the material structure of the zeolite, as well as the rheological behaviour of the zeolite suspension and its aggregation stability had been altered due to the mechanical activation in the stirred media mill. It can be concluded that the zeolite product properties can be modified by mechanical activation in order to produce a high added value tailored material.
Synthesis of Single Crystalline Titanium Oxide and Sodium Titanate Nanorods Via Salt-Assisted Ultrasonic Spray Pyrolysis
Authors: Hwangbo Y. , Yoo J.-H. , Lee Y.-I. 
Published: July 2017

AbstractThe simple and continuous synthesis of single crystalline anatase titanium dioxide and sodium titanate nanorods by a salt-assisted ultrasonic spray pyrolysis method is demonstrated. This method does not require expensive precursors, long reaction time, and physical templates or surfactant. In addition, its continuous nature makes it a suitable method for the large-scale preparation. Moreover, the effect of a salt concentration in a starting solution on material properties, including morphology and phase of the synthesized products was systematically investigated. The synthesized nanorods had one-dimensionality, a single crystalline and the average diameter of 12.3 nm with dual phases of titanium dioxide and sodium titanate by FE-SEM, XRD, HR-TEM as well as FFT-converted SAED pattern analysis.
Effects of Grain Boundary Morphologies on Stress Corrosion Cracking of Alloy 600
Authors: Kim H.P. , Choi M.J. , Kim S.W. , Kim D.J. , Lim Y.S. , Hwang S.S. 
Published: July 2017

AbstractEffects of grain boundary morphologies on stress corrosion cracking (SCC) of Alloy 600 have been studied in 40% NaOH at 315°C using C-ring specimens. The configuration of the grain boundary and the intergranular carbide density were controlled by heat treatment. SCC tests were performed at +150 mV above the corrosion potential. The specimen with a serrated grain boundary showed higher SCC resistance than that with a straight grain boundary. This appears to be caused by the fact that the specimen with the serrated grain boundary has longer SCC path. SCC resistance also increased with intergranular carbide density probably due to enhanced relaxation of stress at intergranular carbide.
Impact of two telemetry transmitter implantation incision suturing methods on the physiological state and condition of perch (Perca fluviatilis)
Authors: Rożyński Maciej , Kapusta Andrzej , Demska-Zakęś Krystyna , Ziomek Elżbieta , Szczerbowski Andrzej , Stawecki Konrad , Zakęś Zdzisław 
Published: July 2017

Abstract
The aim of this work was to determine the impact on European perch, Perca fluviatilis L. (mean body weight – 78.33 g) of the intraperitoneal implantation of telemetry transmitters using different suturing methods. In the first experiment silk sutures were used (experiment I – group ST), while in the second tissue adhesive was used (experiment II – group GT). Following the procedure, the fish were kept for 42 days in a recirculating system. Differences in growth and condition parameters were only noted in the first week of the experiment. Specimens from group GT had lower values for DGR (daily growth rate) and SGR (specific growth rate), but a higher value for FCR (feed conversion ratio) values. For the hematological parameters, lower values of MCV (mean corpuscular volume) and PLT (blood platelets) were noted in group GT, while for the biochemical parameters, lowered ALP (alkaline phosphatase) activity and Mg (magnesium) concentrations were noted in group ST. In group ST, 33.3% of the specimens loss their tags, while in group GT 77.8% did so. Differences in incision healing were only noted in the second week, when specimens in group ST were observed to have fully closed incisions, while in group GT 50% of the incisions were open. Despite the high percentage of implantation incision healing in both groups, because of the high values of tag loss rate, neither method can be recommended for perch. It might be more effective to use tag with external antennae in this species. The method use for closing implantation incisions also must be improved to eliminate tag shedding.
Great cormorant (Phalacrocorax carbo) predation on pikeperch (Sander lucioperca L.) in shallow eutrophic lakes in Poland
Authors: Traczuk Piotr , Kapusta Andrzej 
Published: July 2017

Abstract
Increases in the population abundance of the piscivorous great cormorant (Phalacrocorax carbo) has led to conflicts with fisheries. Cormorants are blamed for decreased fish catches in many lakes in Poland. The aim of this paper is to describe to role of pikeperch (Sander lucioperca) in the diet of cormorants nesting in a colony on the island in Lake Warnołty. Since the breeding colony is located in the vicinity of Lake OEniardwy, the largest lake in Poland, the cormorants use the resources in this lake. In 2009-2016, 18,432 regurgitated fish were collected, of which 593 were pikeperch. The share of pikeperch among fish collected in 2009-2012 did not exceed 2%, but from 2013 this increased substantially to maximum of 38.2% in 2015. The smallest pikeperch had a standard length of 8.4 cm, and the largest 42.5 cm. Pikeperch mean length differed by year, and the length distribution was close to normal. The sizes of the regurgitated pikeperch indicate that cormorants prey almost exclusively on juvenile specimens. The results of the present study indicate that cormorant predation has a significant impact on pikeperch populations in lakes in the vicinity of the colony, and the great cormorants are possibly a significant factor in the effectiveness of pikeperch management. When planning for the management of fish populations in lakes subjected to cormorant predation pressure, it should be borne in mind that predation by this piscivorous bird species impacts the abundance and size-age structure of fish populations.
New xenophytes from the Canary Islands (Gran Canaria and Tenerife; Spain)
Authors: Verloove Filip 
Published: July 2017

Abstract
Recent fieldwork in Gran Canaria and Tenerife (Canary Islands, Spain), mostly between 2012 and 2016, yielded new chorological data for several non-native vascular plant species. The following are considered naturalized and/or potentially invasive: Callistemon viminalis, Casuarina glauca, Chloris barbata, Cyperus difformis, Eucalyptus gomphocephala, E. sideroxylon, Nephrolepis cordifolia, Rumex palustris, Senna × artemisioides (s.l.) and S. × floribunda and are reported for the first time from the Canary Islands. Other first records include: Cascabela thevetia (Tenerife), Cyclospermum leptophyllum (Gran Canaria), Digitaria radicosa (Gran Canaria, Tenerife), Dysphania anthelmintica (Tenerife), Erythrostemon gilliesii (Tenerife), Heliotropium supinum (Tenerife), Limoniastrum monopetalum (Tenerife), Nerium oleander (Tenerife), Pascalia glauca (Tenerife), Phytolacca americana (Tenerife), Podranea ricasoliana (Gran Canaria), Psidium guajava (Gran Canaria), Rumex cristatus (Tenerife), Schinus terebinthifolia (Tenerife), Solandra maxima (Tenerife), Tipuana tipu (Tenerife) and Youngia japonica (Gran Canaria). More than 20 additional taxa also represent chorological novelties but are considered ephemerals. Finally, miscellaneous notes are added for Diplachne fusca subsp. uninervia, Eclipta prostrata, Pluchea carolinensis, Prosopis juliflora and Sida rhombifolia from Gran Canaria.
About Applications of the Fixed Point Theory
Authors: Bucur Amelia 
Published: July 2017

AbstractThe fixed point theory is essential to various theoretical and applied fields, such as variational and linear inequalities, the approximation theory, nonlinear analysis, integral and differential equations and inclusions, the dynamic systems theory, mathematics of fractals, mathematical economics (game theory, equilibrium problems, and optimisation problems) and mathematical modelling. This paper presents a few benchmarks regarding the applications of the fixed point theory. This paper also debates if the results of the fixed point theory can be applied to the mathematical modelling of quality.
Microlearning an Evolving Elearning Trend
Authors: Giurgiu Luminiţa 
Published: July 2017

Abstract
This article is analyzing the meanings of the micro-learning trend, as they have emerged and developed over the last few years. Exploring how the term micro-learning is used to organize and order a set of pedagogical and technological phenomena and concepts in new and interesting ways, it is brought into focus the most popular and widely used learning management platforms that embrace this concept.