bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact Characteristic According to the Structure of Crash Box at the Vehicle
Authors: Min B.S. , Cho J.U.
Published: July 2017

The crash box between a bumper and a car body in automobiles can reduce impacts for car bodies with a bumper at a low-speed collision by preventing the shocks. Also, this crash box is the part playing a very important role for the safety of vehicle and the reduction of repair cost, and many studies have been investigated for the performance. In this study, aluminum foam was inserted in an aluminum crash box to analyze the relationships of deformation, stress and internal energy. The compression characteristics are compared with six cases. In addition, the load due to displacement at experiment for a case is verified by modeling with finite elements and performing the structural analysis. As these study results for investigating characteristics of the crash box, it is thought that the effective designs of crash box to enhance the durability for collision are made possible.
Reaction Kinetics and Morphological Study of TiNb2O7 Synthesized by Solid-State Reaction
Authors: Choi S.H. , Ali B. , Choi K.S. , Hyun S.K. , Sim J.J. , Choi W.J. , Joo W. , Lim J.H. , Lee T.H. , Kim T.S. , Park K.T.
Published: July 2017

Although TiNb2O7is regarded as a material with high application potential in lithium-ion batteries (LIBs) and solid-oxide fuel cells (SOFCs), it has been difficult to find suitable cost-effective conditions for synthesizing it on a commercial scale. In this study, TiNb2O7compounds were synthesized by a solid state synthesis process. For stoichiometrically precise synthesis of the TiNb2O7phase, the starting materials, TiO2and Nb2O5were taken in a 1:1 molar ratio. Activation energy and reaction kinetics of the system were investigated at various synthesis temperatures (800,1000,1200, and 1400°C) and for various holding durations (1,5,10, and 20 h). Furthermore, change in the product morphology and particle size distribution were also evaluated as a function of synthesis temperature and duration. Additionally, quantitative phase analysis was conducted using the Rietveld refinement method. It was found that increases in the synthesis temperature and holding time lead to increase in the mean particle size from 1 to 4.5 μm. The reaction rate constant for the synthesis reaction was also calculated.
Synthesis and Characterization of Antimony Telluride for Thermoelectric and Optoelectronic Applications
Authors: Zybała R. , Mars K. , Mikuła A. , Bogusławski J. , Soboń G. , Sotor J. , Schmidt M. , Kaszyca K. , Chmielewski M. , Ciupiński L. , Pietrzak K.
Published: July 2017

Antimony telluride (Sb2Te3) is an intermetallic compound crystallizing in a hexagonal lattice withR-3mspace group. It creates a c lose packed structure of anABCABCtype. As intrinsic semiconductor characterized by excellent electrical properties, Sb2Te3is widely used as a low-temperature thermoelectric material. At the same time, due to unusual properties (strictly connected with the structure), antimony telluride exhibits nonlinear optical properties, including saturable absorption. Nanostructurization, elemental doping and possibilities of synthesis Sb2Te3in various forms (polycrystalline, single crystal or thin film) are the most promising methods for improving thermoelectric properties of Sb2Te3. Applications of Sb2Te3in optical devices (e.g. nonlinear modulator, in particular saturable absorbers for ultrafast lasers) are also interesting. The antimony telluride in form of bulk polycrystals and layers for thermoelectric and optoelectronic applications respectively were used. For optical applications thin layers of the material were formed and studied. Synthesis and structural characterization of Sb2Te3were also presented here. The anisotropy (packed structure) and its influence on thermoelectric properties have been performed. Furthermore, preparation and characterization of Sb2Te3thin films for optical uses have been also made.
Effect of Hafnium and Zirconium to Glass Forming Ability, Thermal Stability, Plasticity Deformation and Crystallization of Ni-Free Pentabasic Ti-Based Bulk Metallic Glasses
Authors: Oak J.J. , Kim Y.H. , Bae K.C. , Park Y.H.
Published: July 2017

The newly designed Ti-based bulk metallic glass (BMG) in which case of fracture behavior was observed 1990MPa to compressive strength with a wide plastic deformation around 7% after process of elastic deformation. This phenomenon can be compared with those of Ti-based alloys and other Ti-based BMGs and indicates high potential to be applied in use. It was evaluated the Ti-based BMG for thermal stability that the reduced glass parameters, ΔTx,Trgand γ, are 79K, 0.50 and 0.38, respectively. In addition, it reveals high activation energies for crystallization in which are estimated toEx1= 291.77 ±9.71 kJ/mol,Ex2= 588.77 ±28.88 kJ/mol andEx3= 330.26 ±3.61 kJ/mol on kissinger plotting in this study.
Effect of Fe Content on the Microstructure and Mechanical Properties of Ti-Al-Mo-V-Cr-Fe Alloys
Authors: Bae K.C. , Oak J.J. , Kim Y.H. , Park Y.H.
Published: July 2017

To investigate the effect of Fe content on the correlation between the microstructure and mechanical properties in near-b titanium alloys, the Ti-5Al-5Mo-5V-1Cr-xFe alloy system has been characterized in this study. As the Fe content increased, the number of nucleation sites and the volume fraction of theαphase decreased. We observed a significant difference in the shape and size of theαphase in the matrix before and after Fe addition. In addition, these morphological deformations were accompanied by a change in the shape of theαphase, which became increasingly discontinuous, and changed into globular-typeαphase in the matrix. These phenomena affected the microstructure and mechanical properties of Ti alloys. Specimen #2 exhibited a high ultimate tensile strength (1071 MPa), which decreased with further addition of Fe.
Synthesis and Characterization of Si Oxide Coated Nano Ceria by Hydrolysis, and Hydrothermal Treatment at Low Temperature
Authors: Kong M. , Kim H.W.
Published: July 2017

The purpose of this work was to the application of Si oxide coatings. This study deals with the preparation of ceria (CeO2) nanoparticles coating with SiO2by water glass and hydrolysis reaction. First, the low temperature hydro-reactions were carried out at 30~100°C. Second, Silicon oxide-coated Nano compounds were obtained by the catalyzing synthesis. CeO2Nano-powders have been successfully synthesized by means of the hydrothermal method, in a low temperature range of 100~200°C. In order to investigate the structure and morphology of the Nano-powders, scanning electron microscopy (SEM) and X-ray diffraction (XRD) were employed. The XRD results revealed the amorphous nature of silica nanoparticles. To analyze the quantity and properties of the compounds coated with Si oxide, transmission electron microscopy (TEM) in conjunction with electron dispersive spectroscopy was used. Finally, it is suggested that the simple growth process is more favorable mechanism than the solution/aggregation process.
Effect of Ultrasonication Dispersion Technique on Sintering Properties of CNT Reinforced Al-Zn-Mg-Cu Powder
Authors: Rudianto H. , Edtmaier C. , Dlouhy I. , Soukal F.
Published: July 2017

CNT has been researched significantly due to its properties especially mechanical and conductivity properties. Due to strong affinity between particles, dispersion has been remained a problem for its applications. Ultrasonication technique was used to disperse CNT on aluminum powder. Ultrasonication has successfully dispersed CNT on aluminum powder in ethanol. Low energy ball milling for 1h under argon gas with 5:1 ball to powder ratio was used to optimize dispersion of CNT on aluminum. CNT concentration in this research is ranged from 0.1 up to 3wt%. Premix Al-5.5Zn-2.5Mg-0.5Cu powder was used as matrix for this research. Sintering at 580°C for 1h under argon gas was carried to produce high density materials. Pores are still remained on material and it is possibility that pores were caused by agglomeration of CNT. Dispersion high content of CNT is still remained obstacle on this research. Aluminum carbide, Al4C3 is recognized as a ‘bridge between aluminum and CNT for stress transfer was investigated in this research. Raman Spectroscopy, XRD and SEM-EDS were carried out to characterize materials.
Transient Liquid Phase Behavior of Sn-Coated Cu Particles and Chip Bonding using Paste Containing the Particles
Authors: Hwang Jun Ho , Lee Jong-Hyun
Published: July 2017

Sn-coated Cu particles were prepared as a filler material for transient liquid phase (TLP) bonding. The thickness of Sn coating was controlled by controlling the number of plating cycles. The Sn-coated Cu particles best suited for TLP bonding were fabricated by Sn plating thrice, and the particles showed a pronounced endothermic peak at 232°C. The heating of the particles for just 10 s at 250°C destroyed the initial core-shell structure and encouraged the formation of Cu-Sn intermetallic compounds. Further, die bonding was also successfully performed at 250°C under a slight bonding pressure of around 0.1 MPa using a paste containing the particles. The bonding time of 30 s facilitated the bonding of Sn-coated Cu particles to the Au surface and also increased the probability of network formation between particles.
Investigation of the Microstructure and Thermoelectric Properties of P-Type BiSbTe Alloys by Usage of Different Revolutions Per Minute (RPM) During Mechanical Milling
Authors: Yoon S.-M. , Madavali B. , Yoon Y.-N. , Hong S.-J.
Published: July 2017

In this work, p-type Bi0.5Sb1.5Te3alloys were fabricated by high-energy ball milling (MA) and spark plasma sintering. Different revolutions per minute (RPM)s were used in the MA process, and their effect on microstructure, and thermoelectric properties of p-type Bi0.5Sb1.5Te3were systematically investigated. The crystal structure of milled powders and sintered samples were characterized using X-ray diffraction. All the powders exhibited the same morphology albeit with slight differences find at 1100 RPM conditions. A slight grain size refinement was observed on the fracture surfaces from 500 to 1100 RPM specimens. The temperature dependence of Seebeck coefficient, electrical conductivity, and power factors were measured as a function of temperature with different RPM conditions. The power factor shows almost same (~3.5 W/mK2at RT) for all samples due to unchanged Seebeck and electrical conductivity values. The peak ZT of 1.07 at 375K is obtained for 1100 RPM specimen due to low thermal conductivity.
Effect of Acid Dissolution Conditions on Recovery of Valuable Metals from Used Plasma Display Panel Scrap
Authors: Kim Chan-Mi , Dharmaiah Peyala , Kim Hyo-Seob , Koo Jar-Myung , Yoon Jae-Sik , Hong Hyun-Seon , Hong Soon-Jik
Published: July 2017

The objective of this particular study was to recover valuable metals from waste plasma display panels using high energy ball milling with subsequent acid dissolution. Dissolution of milled (PDP) powder was studied in HCl, HNO3, and H2SO4acidic solutions. The effects of dissolution acid, temperature, time, and PDP scrap powder to acid ratio on the leaching process were investigated and the most favorable conditions were found: (1) valuable metals (In, Ag, Mg) were recovered from PDP powder in a mixture of concentrated hydrochloric acid (HCl:H2O = 50:50); (2) the optimal dissolution temperature and time for the valuable metals were found to be 60°C and 30 min, respectively; (3) the ideal PDP scrap powder to acid solution ratio was found to be 1:10. The proposed method was applied to the recovery of magnesium, silver, and indium with satisfactory results.
Improved Mechanical Properties of Al-Si Alloys by Adding an Extrusion Process to Conventional Processing Method
Authors: Han J.Y. , Femi O.E. , Kilicaslan F. , Jeong C.U. , Baeg C.H. , Hong S.J. , Koo J.M.
Published: July 2017

In this study, the mechanical properties of Al-Si alloys was improved by selecting higher Si content and avoiding distortion in Al-Si matrix by adding an extrusion process such that the fabrication processes casting and extrusion were in sequence. Cast billets were extruded at ratios 4:1 and 10:1 to obtained two extruded bars with different processing parameters. The as-extruded samples were characterized and investigated for microstructure and mechanical properties. Optical Microscope was used to examined phase morphologies and microstructures of the extruded Al-Si bars. Mechanical properties were conducted on each sample to study the effectiveness of the additional extrusion process in high Si content Al-Si alloys. The result shows that by increasing the extrusion ratio, the size of the primary Si particle reduces leading to a higher density, better tensile and yield strength compared to the cast billet.
Optimization of Roll Bonding by Hot Rolling in Experimental and Industrial Use
Authors: Szabó G.
Published: July 2017

In this study the major topic were the bonding properties of the layer-clad aluminum sheets. The bonding was performed between AlMn1Si0.8 and AlSi10 alloys using hot rolling (a VON ROLL experimental duo mill). The experimental temperatures were 460, 480 and 500°C. The goodness of bonding was tested by tensile test and T-peel test. T-peel test provided a good description about the quality of bonding. Structure analysis was also performed by light microscopy to detect typical bonding faults. The aim of this investigation is modelling the bonding conformation in experimental conditions. Further aim of this investigation is to produce some typical bonding faults and find the cause of formation. The influence of the rolling temperature and surface roughness on the bonding was also analyzed. Rolling schedule and the role of first pass on the development of perfect bonding were experimentally determined.
Effect of Electroless Ni–P Plating on the Bonding Strength of Bi–Te-Based Thermoelectric Modules
Authors: Kim S.S. , Son I. , Kim K.T.
Published: July 2017

In the present study, electroless Ni–P plating was applied to Bi–Te-based thermoelectric materials as a barrier layer and the effect of the Ni–P plating on the bonding strength of the thermoelectric module was investigated. The bonding strength of the n- and p-type modules increased after being subjected to the electroless Ni–P plating treatment. In the case of the thermoelectric module that was not subjected to electroless Ni–P plating, Sn and Te were interdiffused and formed a brittle Sn–Te-based metallic compound. The shearing mostly occurred on the bonding interface where such an intermetallic compound was formed. On the other hands, it was found from the FE-EPMA analysis of the bonding interface of thermoelectric module subjected to electroless Ni-P plating that the electroless Ni-P plating acted as an anti-diffusion layer, preventing the interdiffusion of Sn and Te. Therefore, by forming such an anti-diffusion layer on the surface of the Bi–Te based thermoelectric element, the bonding strength of the thermoelectric module could be increased.
Microstructure Evolution of Ni-Based ODS Superalloy Powders During Horizontal Rotary Ball Milling
Authors: Lee H.-E. , Kim Y.Su. , Park J.K. , Oh S.-T.
Published: July 2017

Microstructure evolution of Ni-based oxide dispersion-strengthened alloy powders with milling time is investigated. The elemental powders having a nominal composition of Ni-15Cr-4.5Al-4W-2.5Ti-2Mo-2Ta-0.15Zr-1.1Y2O3in wt % were ball-milled by using horizontal rotary ball milling with the change of milling velocity. Microstructure observation revealed that large aggregates were formed in the early stages of ball milling, and further milling to 5 h decreased particle size. The average crystalline size, estimated by the peak broadening of XRD, decreased from 28 nm to 15 nm with increasing milling time from 1 h to 5 h. SEM and EPMA analysis showed that the main elements of Ni and Cr were homogeneously distributed inside the powders after ball milling of 5 h.
Effect of Grinding Fineness of Fly Ash on the Properties of Geopolymer Foam
Authors: Szabó R. , Gombkötő I. , Svéda M. , Mucsi G.
Published: July 2017

Present paper deals with the development of geopolymer foam prepared from ground F class power station fly ash. The effect of the fly ash fineness on the rheology of the geopolymer paste and the foam properties have been investigated. The raw fly ash was ground in a ball mill for various duration, 5, 10, 20, 30, 60 and 120 min. Geopolymer paste was prepared from the raw and ground fly ash with NaOH – sodium silicate mixture as alkaline activator. Geopolymer foam production was made using H2O2as foaming agent. Additionally, the geopolymer material structure was investigated by Fourier transform infrared spectrometer, the foam cell structure was monitored using optical microscopy. The rheological behaviour of the geopolymer paste changed due to the grinding of fly ash (from Bingham plastic to Newtonian liquid). Grinding of fly ash has a significant effect on the physical properties as well as on the cell structure of the geopolymer foam.
Hardness and Microstructure of Mixed Al-CNF Powder Extrusion
Authors: Kim D.-H. , Kim T.-J. , Lim S.-G.
Published: July 2017

In 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

A 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

Electrical 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

This 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

The 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

This 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

In 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

This 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

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

This 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

An 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

Non-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

Industrial 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

Due 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

The 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

Effects 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

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

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

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

The 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

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.
Model for Determining the Consumption of Machinery, Tableware, Fuel, Oils and Lubricants with the Participation of Units from the Bulgarian Army in Humanitarian Operations
Authors: Nichev Nikolay
Published: July 2017

Regulating documents of the Bulgarian Army considered norms for support classic combat operations and in fact Bulgarian Army has no planning methods to be used for planning of humanitarian operations. Solving this problem can be achieved through the use of planning factors. Planning factors are generally based on experience or data on the use of resources from previous operations. The participation of units of the Bulgarian Army in humanitarian operations have failed to bring to the accumulation of data needed to create a suitable planning factors. The purpose of the study is to develop a model by which to bring out planning factors in determining the the consumption of machinery, tableware, fuel, oils and lubricants with the participation of units from the Bulgarian Army in humanitarian operations.
Extracurricular Sport Activities and their Importance in Children Socialization and Integration Process
Authors: Pomohaci Marcel , Sopa Ioan Sabin
Published: July 2017

The importance of sports activities nowadays is showing their effects on the future development of children, extracurricular activities come in the help of the physical education teacher with benefits on children's development. Our study focuses on revealing the importance of extracurricular sports activities in the process of children's socialization and integration. The research sample was formed from two different groups, the experimental group was formed by 25 students (age 10 ± 2.1 years, 13 boys, and 12 girls), that practiced 2 hours a week physical education and other 2 hours a week extracurricular activities like basketball and volleyball; and the sample group formed by 24 students (age 10 ± 1.8 years, 12 boys and 12 girls), that practiced 2 hours a week classic physical education. The results showed us that extracurricular activities have a good impact on children's socialization and integration, the experimental group improved their coefficient of group cohesion from 0.04 at the initial testing to 0.06 at the final test, and the index of cohesion from 0.02 at the initial test to 0.05 at the final testing. Significant differences were found within the experimental group both in the initial and in the final tests (p < 0.05), also significant differences were discovered between the experimental and the sample group in the final measurement (p < 0.05). Conclusions of this research presented that the experimental group had good improvements of cohesion and social integration of children, showing that extracurricular sport activities have a positive impact on improving socialization, developing cohesion and integrate the marginalized children in the social group.
Separation of Contaminants in The Freeze/Thaw Process
Authors: Szpaczyński Janusz A. , White Jeffrey A. , Côté Caroline L.
Published: July 2017

These studies examined the concept of concentration and purification of several types of wastewater by freezing and thawing. The experiments demonstrated that freezing of contaminated liquid contributed to concentration of contaminants in solution as well as significant concentration and agglomeration of solid particles. A high degree of purification was achieved for many parameters. The results of comparative laboratory tests for single and multiple freezing are presented. It was found that there was a higher degree of concentration of pollutants in wastewater frozen as man-made snow than in bulk ice. Furthermore, the hypothesis that long storage time of liquid as snow and sufficient temperature gradient metamorphism allows for high efficiency of the concentration process was confirmed. It was reported that the first 30% of the melted liquid volume contained over 90% of all impurities. It gives great opportunities to use this method to concentrate pollutants. The results revealed that the application of this process in full scale is possible. Significant agglomeration of solid particles was also noted. Tests with clay slurry showed that repeated freezing and thawing processes significantly improve the characteristics of slurry for sedimentation and filtration.
A New Method for Assessing Haemolysis in a Rotary Blood Pump Using Large Eddy Simulations (LES)
Authors: Szwast Maciej , Moskal Arkadiusz , Piątkiewicz Wojciech
Published: July 2017

The opportunity to assess haemolysis in a designed artificial heart seems to be one of the most important stages in construction. We propose a new method for assessing haemolysis level in a rotary blood pump. This method is based on CFD calculations using large eddy simulations (LES). This paper presents an approach to haemolysis estimation and shows examples of numerical simulation. Our method does not determine the value of haemolysis but allows for comparison of haemolysis levels between different artificial heart constructions.
Enhanced Chondrocyte Proliferation in a Prototyped Culture System with Wave-Induced Agitation
Authors: Pilarek Maciej , Godlewska Klaudia , Kuźmińska Aleksandra , Wojasiński Michał , Dąbkowska Katarzyna
Published: July 2017

One of the actual challenges in tissue engineering applications is to efficiently produce as high of number of cells as it is only possible, in the shortest time. In static cultures, the production of animal cell biomass in integrated forms (i.e. aggregates, inoculated scaffolds) is limited due to inefficient diffusion of culture medium components observed in such non-mixed culture systems, especially in the case of cell-inoculated fiber-based dense 3D scaffolds, inside which the intensification of mass transfer is particularly important. The applicability of a prototyped, small-scale, continuously wave-induced agitated system for intensification of anchorage-dependent CP5 chondrocytes proliferation outside and inside three-dimensional poly(lactic acid) (PLA) scaffolds has been discussed. Fibrous PLA-based constructs have been inoculated with CP5 cells and then maintained in two independent incubation systems: (i) non-agitated conditions and (ii) culture with wave-induced agitation. Significantly higher values of the volumetric glucose consumption rate have been noted for the system with the wave-induced agitation. The advantage of the presented wave-induced agitation culture system has been confirmed by lower activity of lactate dehydrogenase (LDH) released from the cells in the samples of culture medium harvested from the agitated cultures, in contrast to rather high values of LDH activity measured for static conditions. Results of the proceeded experiments and their analysis clearly exhibited the feasibility of the culture system supported with continuously wave-induced agitation for robust proliferation of the CP5 chondrocytes on PLA-based structures. Aside from the practicability of the prototyped system, we believe that it could also be applied as a standard method offering advantages for all types of the daily routine laboratory-scale animal cell cultures utilizing various fiber-based biomaterials, with the use of only regular laboratory devices.