bluuebunny/crossref_metadata_2025 huggingface dataset:
High Temperature Oxidation Effect on the Dissolution Rate of Hot-Dip Aluminized Steel in Aluminum Melt
Authors: Mohsenifar Ayeh , Aboutalebi Mohammad Reza , Seyedein S. Hossein
Published: June 2014

Hot dip aluminizing of low carbon steel followed by high temperature oxidation in air was carried out to evaluate the dissolution rate of coated sample in molten aluminum. The microstructure of oxide and aluminide layers was investigated using scanning electron microscopy and X-ray diffraction methods. The characterization of the coating showed that Fe2Al5 has been the major phase formed on the surface of specimen before high temperature oxidation. Isothermal oxidation of the coating as resulted in the formation of Al2O3 while Fe2Al5 phase transformed into FeAl and Fe3Al phases. The coated samples were further subjected to corrosion in molten aluminum. It was proved that the oxide layer formed on the coating and developed FeAl and Fe3Al intermetallic phases play the major role in protecting the specimen from corrosion in molten aluminum.
Effect of Sepiolite Content on Mechanical and Flammability Properties of Ethylene Vinyl Acetate Nanocomposite
Authors: Bidsorkhi Hossein Cheraghi , Mohamad Zurina
Published: June 2014

Ethylene Vinyl Acetate (EVA)/Sepiolite nanocomposites were prepared by melt extrusion using a counter-rotating twin-screw extruder followed by injection molding. Sepiolite was loaded in EVA is varies at 1, 3, 5 and 7 wt%. The mechanical properties of EVA/Sepiolite nanocomposites were studied through tensile test. The flame retardancy of nanocomposites were studied for limiting oxygen index (LOI). LOI tests show that the flame retardancy of nanocomposites were increased with increase ratio of sepiolite in EVA/Sepiolite nanocomposite. The tensile properties of EVA/Sepiolite nanocomposites were also increased with increased Sepiolite content in nanocomposites.
Effect of Vacancy and Stone-Wales Defects on the Shear Strength of Carbon Nanotube-Polymer Interfaces
Authors: Mahboob Monon , Islam M. Zahabul
Published: June 2014

In the present study interfacial characteristics of carbon nanotubes (CNTs) and their composite with different types of defects are calculated using molecular dynamics (MD) simulation. Although single-walled CNTs (SWCNTs) are found to have ultra-high stiffness and strength, an enormous scatter is also observed in available experimental results due to the presence of nanoscale defects such as vacancy and Stone-Wales defects. The current paper investigates the influences of Stone-Wales (S-W) and vacancy defects on the mechanical properties of composites containing defective CNTs.
Synthesis and Characterization of Mn2+ Doped ZnS Using Reverse Miceller Method
Authors: Mohd Ibrahim Rahizana , Masturah Markom , Abdullah Huda
Published: June 2014

In this work we synthesized the monodisperse of Zn1-xMnxS with x =0.00,0.02,0.04,0.06,0.08 and 0.10 nanoparticles by reverse micelle method using sodium bis (2-ethylhexyl) sulfosuccinate (AOT) as surfactant. The prepared particles were characterized using UV-Visible Spectroscopy, X-ray diffraction (XRD), Transmission Electron Microscopy (TEM) and Photoluminescence (PL) for size, morphology and optical of the samples .UV-vis absorbance spectra for all of the synthesized nanoparticles show the maximum absorption for all samples is observed at range 210 - 300 nm . The absorption edge shifted to lower wavelengths when doping with ion Mn as per UV-Vis spectroscopy. The band gap energy values were increase from 4.50eV to 4.90 eV. This blue shift is attributed to the quantum confinement effect. The size of particles is found to be 3-5nm range. The Mn2+ doped ZnS nanoparticles using reverse micelles method shows the enhance of PL intensity results in monodisperse nanoparticles.
Keywords: Nanoparticles; UV-vis absorbance spectra; quantum confinement effect; photoluminescence.
Synthesis, Optical, Photocatalytic and Bactericidal Properties of Nanocrystalline ZnO Powders by Precipitation Method
Authors: Suwanboon Sumetha , Amornpitoksuk Pongsaton , Bangrak Phuwadol
Published: June 2014

Nanocrystalline ZnO powders were synthesized by precipitation method. The n-propylamine was used as capping agent. The crystallite size of ZnO powders depended on the n-propylamine concentration. ZnO powders exhibited as agglomerated spherical shape. The optical band gap of ZnO powders were varied in a range of 3.204-3.219 eV. The photocatalytic efficiency of ZnO powders for degradation of methylene blue (MB) increased as a function of UV irradiation time and the photocatalytic efficiency was over 80% after UV irradiating for 1 h. The highest photocatalytic efficiency was 96% after UV irradiating for 1 h obtained from nanocrystalline ZnO powders modified with 0.025 mol of n-propylamine (R = 1). Nanocrystalline ZnO powders caused more damage to Staphylococcus aureus (S. aureus) than Escherichia coli (E. coli).
Quasi-Static Indentation Behaviour of Glass Fibre Reinforced Polymer
Authors: Azwan Syed Mohd Saiful , Yazid Yahya Mohd , Amran Ayob , Abdi Behzad
Published: June 2014

Fibre reinforced polymer (FRP) plates subject to quasi-static indentation loading were studied. The plates were fabricated from three layers of chopped strand mat glass fibre and polyester resin using vacuum infusion process. Indentation tests were conducted on the plates with loading rates of 1 mm/min, 10 mm/min, 100 mm/min and 500 mm/min using a hemispherical tip indenter with diameter 12.5 mm. The plates were clamped in a square fixture with an unsupported space of 100 mm × 100 mm. The loads and deflections at the indented location were measured to give energy absorption-deflection curves. The results showed that the loading rate has a large effect on the indentation behaviour and energy absorbed.
The Effect of Wollastonite Filler on Thermal Performance of Intumescent Fire Retardant Coating
Authors: Zia-ul-Mustafa Muhammad , Ahmad Faiz , Megat-Yusoff Puteri S. M. , Aziz Hammad
Published: June 2014

Various types of intumescent fire retardant coatings (IFRCs) have been used to protect the substrates exposed to fire. In current study, high temperature filler Wollastonite (W) filler was used to improve fire performance of intumescent fire retardant coating. The basic ingredients of the coating were ammonium poly-phosphate (APP) as acid source, expandable graphite (EG) as carbon source, melamine (MEL) as blowing agent in epoxy binder, boric acid as additive and hardener as curing agent. In this study a range of coating formulations were developed by using different weight percentages of Wollastonite filler. The coated steel substrate samples were tested for fire performance using Bunsen burner and char expansion was measured using furnace fire test. Composition of the char was determined by X-ray diffraction (XRD) technique. The char morphology was studied using field emission scanning electron microscopy (FESEM). Results showed that Intumescent coating with addition of Wollastonite filler enhanced anti-oxidation of the char. Presence of phosphorus, calcium and silicon in char layer further improved the thermal stability of char.
Basalt Carbon Hybrid Composite for Wind Turbine Rotor Blades: A Short Review
Authors: Mengal Ali Nawaz , Karuppanan Saravanan , Wahab Azmi Abdul
Published: June 2014

Wind turbine blades are the major structural element and highest cost component in the wind power system. Modern wind turbine blade sizes are increasing, and the driving motivation behind this is to increase the efficiency and energy output per unit rotor area, and to reduce the cost per kilowatt hour. However due to the increase in size the material selection for wind turbine has become critical and complex. To achieve the desired materials to improve the design of wind turbine blades several factors such as high fatigue strength, less weight, less cost and potential of recycling must be focused. Basalt fiber is a relative newcomer to fiber reinforced polymers and structural composites. Basalt fiber with their excellent mechanical properties represents an interesting alternative composite material for modern wind turbine blades. Some manufacturers claim that basalt fiber has similar or better properties than S-2 glass fiber and its cheaper than carbon fiber. Basalt fiber together with carbon fiber are the most advanced and interesting area of hybrid technologies. This paper reviews extra ordinary properties of basalt fiber over other fiber reinforced composites and highlight how the basalt special properties together with carbon fiber will reduce the weight and cost of wind turbine blades while improving their performance. This paper also demonstrates why the basalt carbon hybrid composite material will be an ideal alternative for the wind turbine rotor blades.
Effect of Maleic Anhydride Grafted Poly(actic acid) on Properties of Sawdust/Poly(lactic acid) Composites Toughened with Poly(butylene adipate-co-terephthalate)
Authors: Nomai Jiraporn , Jarukumjorn Kasama
Published: June 2014

Sawdust/poly (lactic acid) (PLA) composites toughened with poly (butylene adipate-co-terephthalate) (PBAT) were prepared using a melt blending process. Mechanical, thermal and morphological properties of the composites were investigated. With the addition of PBAT into the sawdust/PLA composite, elongation at break and impact strength increased whereas tensile strength and tensile modulus decreased. In addition, thermal stability of the PLA composite improved with the presence of PBAT. Maleic anhydride grafted poly (lactic acid) (PLA-g-MA) was used as a compatibilizer to improve the compatibility of sawdust/PLA/PBAT composites. The compatibilized composites showed higher mechanical properties and thermal decomposition temperatures than that of the uncompatibilized composite due to improved interfacial adhesion between constituents of the composites. The optimum content of PLA-g-MA for sawdust/PLA/PBAT composites was 5 wt%. SEM micrographs revealed some features of ductile fracture in the composites toughened with PBAT and confirmed that PLA-g-MA improved the compatibility of the composites.
Effects of Sawdust Content and Alkali Treatment on Mechanical and Flame Retarding Properties of Sawdust/Recycled High Density Polyethylene Composites
Authors: Jarapanyacheep Rapisa , Jarukumjorn Kasama
Published: June 2014

Sawdust/recycled high density polyethylene (rHDPE) composites were prepared and their mechanical properties, flammability and morphology were investigated. Sawdust was used at contents of 30, 40 and 50 wt%. With increasing sawdust content, tensile strength and elongation at break of the composites decreased whereas tensile modulus increased. Flexural properties showed the same trend as tensile properties. Flammability of the composites enhanced with increasing sawdust content. Mechanical properties of alkali treated sawdust/rHDPE composites were higher than those of untreated sawdust/rHDPE composites at all sawdust contents. Moreover, alkali treatment improved flame retardancy of the composites. SEM micrographs showed that alkali treatment enhanced the interfacial adhesion between sawdust and rHDPE matrix.
Electron Beam Crosslinking of EVA/ENR-50/HNTS Nanocomposites in the Presence of Trimethylol Propane Triacrylate, TMPTA
Authors: Kamal Rudin Amirah , Mohamad Zurina , Ratnam Chantara Thevy , Abu Bakar Aznizam
Published: June 2014

Ethylene vinyl acetate/ Epoxidised natural rubber/ Halloysite nanotube (EVA/ENR-50/HNT) nanocomposite was prepared through melt blending process using twin screw extruder at 120 oC and 50 rpm of screw speed. The ratio of EVA/ENR-50/HNT was fixed at 80:20:4. The nanocomposites were irradiated with a 3.0 MeV electron beam machine at doses ranging from 50 to 200 kGy in air at room temperature. The effect of irradiation dose and co-agent Trimethylol Propane Triacrylate (TMPTA) on tensile strength and gel content of EVA/ENR-50/HNT nanocomposite were studied. It was found that the tensile strength and gel fraction of the EVA/ENR-50/HNT nanocomposites increased with the increased of irradiation dose. In the presence of TMPTA, a better performance in tensile strength was achieved due to the increased efficiency of irradiation induce crosslinking of EVA/ENR-50/HNT nanocomposite.
Quasi-Static Flexural and Indentation Behaviour of Polymer-Metal Laminate
Authors: Azwan Syed Mohd Saiful , Yazid Yahya Mohd , Amran Ayob , Abdi Behzad
Published: June 2014

Metal-polymer laminates were subjected to quasi-static flexural and indentation loading. The laminates were made of two aluminium skins heat-bonded (laminated) to a core made of polyethylene plastic material. The samples were trimmed into standard-sized beams and panels which were then tested in flexural and indentation using the Instron universal testing machine at loading rates of 1 mm/min, 10 mm/min and 100 mm/min. The load-displacement and energy absorption curves of the composite beams were recorded. It was found that the loading rate has a large effect on flexural and indentation behaviour of aluminium composite laminate.
Engineering of Lead-Free Piezoelectrics in Alkali Niobate Ceramic System: Improvement in Density by Two-Step Mixing Process
Authors: Kakimoto Kenichi , Ishihara Satoru , Watanabe Momoko
Published: June 2014

Lead-free Li0.06(Na,K)0.94NbO3 (LNKN) piezoelectric ceramics were sintered by a new process, “two-step mixing process”, in which a part of alkali source powders (RA) was initially preserved and mixed with the rest matrix powders after the calcinations step, in order to improve bulk density. Sintering of the LNKN ceramics was improved by this process, and the sample with RA = 5% had the highest bulk density of 4.34 g/cm3 (ca. 95%TD). The pore shape and the fracture morphology of the samples suggested the formation of a liquid phase. The present results indicated that the two-step mixing process was an universal approach for improvement in the densification of alkali niobate ststem.
Iron Composite Anodes for Fabricating All-Solid-State Iron-Air Rechargeable Batteries
Authors: Tsuneishi Taku , Esaki Takuma , Sakamoto Hisatoshi , Hayashi Kazushi , Kawamura G. , Muto Hiroyuki , Matsuda Atsunori
Published: June 2014

Hydroxide ion conductors containing KOH were prepared for application in an all-solid-state Fe–air battery. ZrO2 and Mg–Al layered double hydroxide (LDH) were employed as the matrix materials. The ionic conductivity and conducting ion species were evaluated by impedance and electromotive force measurements. Repeated charge and discharge were achieved by using negative electrodes composed of the solid electrolyte and iron oxide-supported carbon.
Chemical Reactivity and Cathode Properties of LaCoO3 on Lanthanum Silicate Oxyapatite Electrolyte
Authors: Mihara Shunya , Kobayashi Kiyoshi , Akashi Takaya , Sakka Yoshio
Published: June 2014

Chemical reactivity and cathode properties of LaCoO3 were investigated using new oxide ion conductor, lanthanum silicate oxyapatite. The LaCoO3 is found to be good candidate for cathode of the lanthanum silicate oxyapatite solid-electrolyte since no chemical reaction occurred between the LaCoO3 and lanthanum silicate oxyapatite heating at 1273 K for 60 h in air. Based on electrochemical measurements, lower overpotential between the LaCoO3 and lanthanum silicate oxyapatite was confirmed compared to the overpotential at YSZ/LaCoO3 interface. From analysis on the extended interfacial conductivity as function of oxygen activity at the triple phase boundary at fixed temperature, the overpotential evaluated by impedance spectra is the rate limiting process by oxygen diffusion on the LaCoO3 surface. Comparing to the bulk conductivity of LaCoO3, the electrode resistance evaluated by impedance spectra was confirmed to be different from the electrical transport properties of the LaCoO3 bulk.
A Model for Estimating Internal Stress during Sintering of Ceramic Multiphase Laminates
Authors: Yasuda Kouichi , Nakayama Tadachika , Tanaka Satoshi
Published: June 2014

A mechanical model is proposed to estimate internal stress during sintering of ceramic multiphase laminates. A symmetrical multi-layered laminate is assumed, and one-dimensional elastic analysis is carried out on the change in stress of each layer during sintering, based on the differences in sintering strain, thermal expansion strain and phase transformation strain between the layers. By taking a limit such that the thickness of each layer approaches infinitesimally small, the internal stress expression can be extended into the case of the materials with continuous compositional change (viz. functionally gradient materials).
Preparation and Electrical Property of Calcia Stabilized Zirconia Ceramics
Authors: Chen Chang Lian , Wang Hong Quan , Ji Jia You , Luo Ma Ya , Wu Bo , Hu Ming Wei , Xia Hao Fu , Huang Zhi Liang
Published: June 2014

In this paper, using ZrO2 and Ca (NO3)•4H2O as raw materials, we prepared a series of calica stabilized zirconia (CSZ) ceramics by pressureless sintering method. The results show that the relative densities of all sintered samples are above 90%, and the sintered samples are composed of cubic, tetragonal and monoclinic ZrO2, and the main phase is cubic ZrO2 and tetragonal ZrO2. The content of cubic phase increases with the increase of sintering temperature and adding CaO content. The grain size of the sintered samples is relatively uniform and some pores exist. Increasing the additive amount of CaO, the conductivity first rises and then decreases, and the conductivity value of the sample containing 5wt% CaO is the maximum. When the sintering temperature is up to 1600 oC, the conductivity of the sample containing 5wt% CaO is up to 0.016S•cm-1 at 800 oC. Furthermore, the conductivity of sintered samples is increasing with the increase of test temperature according to the Arrhenius equation.
Preparation and Study of (1-m)(Mg0.8Zn0.2)TiO3·m{Ba4Nd28/3Ti18O54·0.18Bi2O3} Microwave Dielectric Ceramics
Authors: Ji Xiao Li , Hu Peng Fei , Zhang Song , Zhai Cheng C. , Yi Fang
Published: June 2014

In this work, the microwave dielectric ceramic (1-m)(Mg0.8Zn0.2)TiO3·m{Ba4Nd28/3Ti18O54·0.18Bi2O3}(m=0.1~0.4)(MZT-BNT) was studied to improve dielectric properties. The results of the dielectric properties, density, XRD and SEM show that the value of m and the sintering temperature affected the structure and properties of the ceramics. MZT-BNT composite system is a two-phase composite system. With the adding of BNT, the dielectric properties of MZT increase significantly. As m value increases, the bulk density and the dielectric constant of the composite system increase, while the quality factor reduces and the temperature coefficient of resonant frequency is close to zero. The dielectric properties of MZT-BNT sintered at 1200 °C (m = 0.3) are εr = 34.03, Qf = 7177 GHz,τf = -3.39 ppm/°C, respectively.
Effect of Oxygen Flow Rate on Electrical and Optical Properties of ATO Thin Films Prepared by RF Magnetron Sputtering
Authors: Yang P. , Jiang L.R. , Wu Jun Yan , Chen Fei , Galaviz-Pérez Jorge Alberto , Shen Qiang , Schoenung Julie M. , Zhang Lian Meng
Published: June 2014

Transparent conducting antimony doped tin oxide (ATO) films were sputtered on quartz glass substrates by RF magnetron sputtering at an oxygen flow rate ranging from 0 to 15 sccm. The films were prepared at room temperature and annealed for 15 min in air atmospheres at a temperature of 450 °C. The effect of oxygen flow rate has been investigated by comparing eletrical and optical properties of ATO films. The results suggest that, oxygen flow rate has a great impact on Sb5+/Sb3+ ratio and lattice structure integrity, which finally affects the transmittance and electrical resistivity. With the increase of oxygen flow rate, the grain size is enlarged, which leads to a higher average optical transmittance. On the other hand, with oxygen flow rate increasing, the Sb5+/Sb3+ ratio first increases and then decreases sharply when the oxygen flow rate exceeds 5 sccm. The increase of Sb5+/Sb3+ ratio results in the increase of carrier concentration and finally contributes to a decrease of electrical resistivity. The optimal resistivity is 8.9×10-2 Ω·cm and the average transmittance is about 95% at an oxygen flow rate of 5 sccm.
Spark Plasma Sintering and Characterization of WC-Co-cBN Composites
Authors: Zhang Jian Feng , Tu Rong , Goto Takashi
Published: June 2014

WC-Co-cBN composites were consolidated by SPS at 1373 to 1673 K under a moderate pressure of 100 MPa. The addition of cBN increased the starting and finishing temperature of shrinkage and decreased the relative density of WC-Co. The relative density of WC-(10-20 vol%) cBN composites was about 97-100% at 1573 K and decreased with increasing the sintering temperature to 1673 K due to the phase transformation of cBN to hBN. The highest hardness and fracture toughness of WC-Co-20 vol% cBN composite sintered at 1573 K were 23.2 GPa and 8.0 MP m1/2, respectively.
Densification of Nanocrystalline Ceramics by Combustion Reaction and Quick Pressing
Authors: Liu Jiang Hao , Fu Zheng Yi
Published: June 2014

The technique of combustion reaction and quick pressing was adopted to prepare dense nanocrystalline ceramics. The densification process of magnesia compact with a particle size of 100 nm was investigated, under the applied pressure of up to 170 MPa, and the temperature of 1740–2080 K with ultra-high heating rate of above 1700 K/min. As a result, pure magnesia ceramics with a relative density of 98.8% and an average grain size of 120 nm was obtained at 1740 K and 170 MPa, while the ones with decreased relative density and increased grain size were produced under the increasing temperature and the identical pressure conditions. The results indicated that grain growth of the nanocrystalline magnesia was effectively restrained by the combined effect of the ultra-high heating rate and the high pressure. Moreover, under the particular sintering conditions, there existed an appropriate temperature range for the preparation of dense nanocrystalline magnesia, and the excessive temperature would not only exaggerate grain growth but also impede densification.
Microstructure of LiAl5O8 and LiAlO2 Films Prepared by Laser CVD
Authors: Chi Chen , Katsui Hirokazu , Tu Rong , Goto Takashi
Published: June 2014

α-LiAl5O8, γ-LiAlO2, α-Al2O3and those composite films were prepared on AlN polycrystalline substrates by laser chemical vapor deposition (LCVD), and the effects of total pressure (Ptot) and the molar ratio of Li to Al (RLi/Al) on the morphology and deposition rates were investigated. The typical morphology of single-phase γ-LiAlO2films prepared atRLi/Al> 1.0 andPtot> 400 Pa was granular, whereas γ-LiAlO2films prepared atPtot< 200 Pa and γ-LiAlO2-α-LiAl5O8composite films had pyramidal grains. Single-phase α-LiAl5O8films showed polygonally faceted morphologies. Composite films of α-LiAl5O8and α-Al2O3consisted of carifllower-like and faceted grains. A single-phase γ-LiAlO2film deposited at 200 Pa showed the maximum deposition rate of 48 μm h-1.
Effects of C/Si Ratio on the Structure of β-SiC Film by Halide CVD
Authors: Han Ming Xu , Zhou Wei , Zheng Ding Heng , Tu Rong , Zhang Song , Goto Takashi
Published: June 2014

Thick (over 1 mm) β-SiC films were deposited at a deposition temperature of 1823 K and a total pressure of 4 kPa by halide CVD using SiCl4 and CH4as precursors, and H2 as carrier gas. The maximum deposition rate was 1125 μm h−1. The SiC films showed strong (220) preferred orientation. The grain size increased from 20 to 100 μm with increasing C/Si ratio.
Preparation and Density Control of PMMA Microcellular Foams via Supercritical Carbon Dioxide Foaming
Authors: Li Mei Juan , Xiang Kun , Luo Qiang Guo , Shen Qiang , Zhang Lian Meng
Published: June 2014

Microcellular polymeric foam is a new class of materials which has been widely used in many industries. The foaming of polymethyl metacrylate (PMMA) using supercritical carbon dioxide (ScCO2) which is inexpensive and environmental friendly has been studied to better understand the foaming process. The pieces of PMMA are put into a saturation vessel of which temperature and pressure are kept constant. Supercritical carbon dioxide (ScCO2) at temperature between 65 °C and 105 °C and pressure between 8 MPa and 16 MPa is used as a foaming agent. After saturation of carbon dioxide, rapid decompression of ScCO2 saturated PMMA yields expanded microcellular foams. The densities of foamed PMMA materials are tested by true density analyzer, while the microstructures of a variety of density foamed PMMA materials are characterized by scaning electron microscopy (SEM). The cell size and cell density are calculated via image analysis. The effect of the process condition on the cell morphologies and mass density of the foam is investigated by considering the solubility of carbon dioxide in PMMA. The relationship between the mass density of foamed PMMA (ρ) and foaming temperature (T) and pressure (P) are respectively certained quantificationally.
Synthesis and Characterization of Dense Mesoporous Alumina
Authors: Nakahira Atsushi , Nishimoto Hironobu , Hamada Yukitaka , Yamasaki Yuki
Published: June 2014

Dense mesoporous alumina bulks were successfully synthesized by a hydrothermal hot-pressing (HHP) method for mesoporous alumina powders prepared as starting material with a high BET surface area and narrow pore size distribution. As a result, mesoporous alumina HHP bulks had high density with uniformity pore size distribution and a high specific surface area. Their microstructural features for dense mesoporous alumina bulks were observed by SEM. The characterization of mesopores was examined.
Precipitate Phases and Mechanical Properties of Heat-Treated ASTM F 90 Co-Cr-W-Ni Alloy
Authors: Ueki Kosuke , Ueda Kyosuke , Narushima Takayuki
Published: June 2014

The precipitation behavior during heat treatment and resulting mechanical properties of ASTM F 90 Co-20Cr-15W-10Ni (mass%) alloys were investigated with regards to their biomedical applications. Heat treatment was conducted at temperatures of 873 to 1623 K, for a holding time of 259.2 ks. The precipitates produced were then electrolytically extracted from the alloys and analyzed by X-ray diffraction (XRD). This revealed that the precipitates formed were an M23X6type and/or η-phase (i.e., an M6X-M12X type). The M23X6-type precipitate was detected across the entire heat-treatment temperature range; however, the η-phase precipitate was only detected at 1073 to 1473 K, becoming dominant at 1173 to 1373 K. The formation of M23X6type precipitates at 873 K is shown to improve the mechanical properties of this alloy, whereas the domination by the η-phase precipitate at higher temperatures causes deterioration in the ductility.
Diffusion Mechanism and Kinetics of Diffusion Bonded Mg/Ni/Al Joint
Authors: Zhang Jian , Luo Qiang Guo , Shen Qiang , Zhang Lian Meng
Published: June 2014

Mg and Al were bonded successfully by means of diffusion bonding using Ni interlayer. The microstructure, diffusion mechanism and regulation of atom diffusion were investigated by means of scanning electron microscopy (SEM), X-ray diffraction (XRD) and electron probe microanalysis analysis (EPMA). The results showed that the joints consisted of Mg-Ni interface and Al-Ni interface, and there were Mg2Ni formed in the Mg-Ni interface and Al3Ni formed in the Al-Ni interface, respectively. Diffusion activation energy of Mg and Al were lower than that of Ni in the Mg-Ni and Al-Ni interface. The thickness (x) of Mg2Ni and Al3Ni can be expressed as x2=3.97×10-4 exp (-139600/RT) (t-t0) and x2=8.62×10-3 exp (-174200/RT) (t-t0) with heating temperature (T) and holding time (t).
Investigation of Excitation Mechanism of Cu II Lines under Different Atmospheres
Authors: Lei Zhang
Published: June 2014

The excitation mechanism of Cu II lines under an Ar and Ne glow discharge plasmas were investigated. Charge transfer collision is the domain excitation mechanism which resulting into the intensive emission of Cu II lines at particular wavelength. Under Ne glow discharge plasma, charge transfer collision and Penning type collision makes great contribution to the violently emission of particular Cu II lines.
Consolidation of SiC Powder Coated with SiO2 Nanolayer by Spark Plasma Sintering
Authors: He Zhen Hua , Katsui Hirokazu , Tu Rong , Goto Takashi
Published: June 2014

Silica (SiO2) nanolayer was coated on silicon carbide (SiC) powder by rotary chemical vapor deposition (RCVD). The SiC/SiO2 composite were consolidated by spark plasma sintering (SPS) at 1923 K using the SiO2 coated SiC powder. The relative density and hardness of the SiC/SiO2 composites increased with increasing SiO2 content, and were 97% and 17 GPa, respectively, at SiO2 content of 22 mass%. The relative density and hardness of a composite consolidated using the mixture powders of SiC and SiO2 (22 mass%) at 1923 K were 81% and 8 GPa, respectively.
High-Speed Deposition of SiC Thick Film by Halide Precursor
Authors: Han Ming Xu , Zhou Wei , Zheng Ding Heng , Tu Rong , Zhang Song , Goto Takashi
Published: June 2014

Polycrystalline ڂ˽SiC thick film with mm-scaled thickness was deposited on a graphite substrate using a gaseous mixture of SiCl4 + CH4 and H2 at temperatures ranging from 1573 to 1823 K by chemical vapor deposition. Effect of deposition temperature (Tdep) on deposition rate, surface morphology and preferred orientation has been studied. The preferred orientation changed from <111> to <110> with increasing Tdep. The maximum deposition rate (Rdep) of 1125 ڌ̽˰̸−1 has been obtained. The surface morphology has changed from six-fold pyramid to five-fold facet with increasing Tdep.
Influence of the Process Temperature of Spark Plasma Sintering on Micorsturcture and Nanoindentation Hardness/Young’s Modulus of WC-8wt%Co
Authors: Zhang Jian Feng , Burkel Eberhard
Published: June 2014

WC-8wt%Co nanopowder was consolidated by spark plasma sintering at process temperatures (TSPS) from 1100 to 1400 °C. The nanoindentation hardness and Young’s modulus of the consolidated specimens were measured under different peak load levels (Pmax). The hardnesses and modulus of WC-8wt% Co shows a clear dependence on the microstructures and peak load levels. At 1200 and 1300 °C, the hardness and modulus were higher than those at 1100 and 1400 °C due to the higher relative density and fine grain size. The relationship of stiffness (S) and contact depth (hc) of nanoindentation was discussed.
Effect of pH on the Microstructure and Purity of Copper-Coated Tungsten Composite Powders Prepared by Electroless Plating
Authors: Ye Jing , Chen Wen Shu , Luo Qiang Guo , Li Mei Juan , Shen Qiang , Wang Chuan Bin , Zhang Lian Meng
Published: June 2014

High-performance copper-coated tungsten composite powders were successfully prepared using electroless plating at an appropriate pH in the plating bath. The effect of pH value in the plating bath on the microstructure and purity of the coated Cu layer was studied systematically. With the increase of pH in the bath, the surface roughness, particle size and average grain size of coated Cu increased, and the particle shape gradually changed from round into square block. At pH 12–12.5, coated Cu was highly pure with very little oxygen content (less than 0.09 wt.%). The promotion effect of the increased pH on both main electroless plating reaction and side reactions causes the changes of surface morphology, average grain size of Cu and the oxygen content in the composite powders.
A Wettability Tunable Surface of Nafion® with Controlling the Flip-Flop Property by DC Applied Voltage
Authors: Wei X. , Mogami I. , Kawamura G. , Muto Hiroyuki , Matsuda Atsunori
Published: June 2014

The flip-flop property is an attractive phenomenon on the surface of Nafion® thin film. The sulfonic groups which are hydrophilic can change the wettability of the surface by lift up or curling down. In this study, an applied voltage makes the control of sulfonic groups become available. It has been proved that when a positive voltage is loading to the film through a conductive droplet, the flip-flop property can be enhanced. Being the opposite, it also can be inhibited by a negative voltage.
TL Properties of Pure Al2O3 Grown by the Micro-Pulling down Method
Authors: Kurosawa Shunsuke , Bispo Lucas , Shoji Yasuhiro , Seki Mafuyu , Yokota Yuui , Chubaci Jose F.D. , Yoshikawa Akira
Published: June 2014

Carbon-doped Al2O3is used as a material for dosimeter using thermoluminescence (TL) technique or optically stimulated luminescence (OSL) technique, and the emission bands are originated from defect emission. We have an original crystal growth named micro-pulling down (μ-PD) method which had higher temperature graduation during the crystal growth. Thus, crystal defect is easy to be formed without some dopant using the μ-PD method. We grew pure Al2O3samples with different heating condition, and different peaks in TL spectra were obtained among the pure Al2O3.
Optical and Scintillation Properties of Cr Doped Y3Ga5O12 Crystal for Infra-Red Scintillators
Authors: Yamaji Akihiro , Kurosawa Shunsuke , Suzuki Akira , Pejchal Jan , Kamada Kei , Yokota Yuui , Yoshikawa Akira
Published: June 2014

We evaluated optical and scintillation properties of a Cr 0.5%:Y3Ga5O12 (YGG) and Cr 0.5%:Y3Al5O12 (YAG) crystals grown by the micro-pulling down method for infrared emission scintillators. In the photoluminescence and X-ray induced radioluminescence measurements, the emissions peaks of Cr:YGG were located in the longer wavelength than those of Cr:YAG. Radioluminescene spectrum of Cr:YGG had a broad peak at 716 nm related to Cr3+2E→4A2 and 4T→4A2 transitions.
Quaternary stratigraphy and geomorphology of Charlie Lake [94A] map area, British Columbia
Authors: Mathews W H
Published: June 2014

The Charlie Lake map-area lies at the western edge of the Great Plains and extends to within 10 miles of the Rocky Mountain Foothills. It is underlain by gently dipping Cretaceous sandstones and shales which contribute to a subdued topography including
northwesterly trending belts of hilly and lowland terrain. The Laurentide Ice Sheet reached the Charlie Lake area on at least three separate occasions during the Quaternary. Ice from the mountains to the west also reached the area, with the last major mountain glaciation being essentially
contemporaneous with the last Laurentide Glaciation. Occurrences of fluviatile gravels, similar in size distribution and provenance to those of the present Peace River, are known at three different levels. The highest, about 1000 feet above Peace River, may be of preglacial age. The second, roughly
500 feet above Peace River, belongs to an early interglaciation; and the third, 100 to 200 feet above Peace River, belongs to the last interglaciation. A radiocarbon date of 27 400 years B. P. is identified with this last unit. The two interglacial gravel units are each overlain by sands, silts, and
clays attributable to aggradation and ponding of Peace River by advancing Laurentide ice which ultimately covered these sediments with till. Sands and clays overlying the younger till were deposited in ice-dammed lakes during the retreating stages of Laurentide Glaciation. Isostatic tilting of the
shorelines of these lakes, which rise westerly at about 2 feet per mile, is attributed to rebound following a late retreat of the western glaciers. Postglacial entrenchment by Peace River has occurred to a depth of as much as 700 feet, and the bedrock floor of this trench with its cover of modern
flood plain gravels lies almost 200 feet lower than any earlier post-Cretaceous erosion surface. Incision to lesser depths has been produced by tributaries of Peace River. Quaternary history has played an important role in controlling movement, storage, and availability of groundwater, in
influencing landslides along river banks, in localizing supplies of gravel, as well as in perhaps affecting early postglacial migrations by animals and man.
A lichenometric study of Holocene rock glaciers and neoglacial moraines, Frances Lake map area, southeastern Yukon Territory and Northwest Territories
Authors: Dyke A S
Published: June 2014

Different ages of rock glaciers and Neoglacial moraines in southeast Yukon are readily differentiated on the basis of the size structures of their Rhizocarpon populations and per cent lichen cover. Most rock glaciers formed ji-om talus during the middle Holocene
but formation and flow continued thereafter. Perhaps conditions for formation were climatically enhanced at several times during the middle and late Holocene but the apparent climatic signal is weak and equivocal. With one exception, glacial advances date from the last four centuries. Moraines are
of several ages but there is no clear correlation between glacial advances and formation of rock glacier lobes during the last four centuries. Climatic change that led to Neoglaciation triggered only minor, if any, rock glacierization of talus, and whatever conditions led to massive rock
glacierization of talus during the middle Holocene failed to trigger glacier growth. Rock glacierization is probably self regulated and occurs at a threshold talus thickness and ice content. Thresholds likely vary with geotechnical properties of talus, particularly grain size, and are only slightly
modulated climatically. Large Rhizocarpon lichens increase their diameters at the same rate as small ones so the growth rate is constant following the initial "great period"; hence the fundamental premise of lichenometry is correct. Rhizocarpon communities show no symptoms of senescence at 5000
years of age so the genus is useful in lichenometry beyond that.
Scitovsky, Behavioural Economics, and Beyond
Authors: Pugno Maurizio
Published: June 2014

Scitovsky is known as a forerunner of behavioural economics simply because he drew heavily on psychology and claimed that people’s choices may be ‘joyless’ (Scitovsky, The joyless economy, 1976). However, a careful reformulation of his analysis shows that he anticipated a number of insights (also with respect to Kahneman’s ‘two-systems of thought’) which suggest new lines of inquiry from an original and different perspective. These insights of Scitovsky regard the following aspects: Uncertainty as a condition where the outcomes of choosing a particular option (novelty) is partially unknown; the case of individual ‘consumption skill’ (inclusive of emotions) that finds this uncertainty desirable when it is challenging; the case of increasing such skill so as to change preferences and make choices more efficient; the case of failing to increase such skill so as to make addictive harmful products an alternative and more tempting option.
Readiness to deny group’s wrongdoing and willingness to fight for its members: the role of Poles’ identity fusion with the country and religious group
Authors: Besta Tomasz , Gómez Ángel , Vázquez Alexandra
Published: June 2014

Background

Identity fusion is a powerful visceral feeling of oneness with the group. Dozens of studies have demonstrated that identity fusion is a powerful predictor of endorsement of extreme behavior for the group. However, most research has been conducted with Spanish and/or North-American participants, and focused on the country as the target group.

Participants and procedure

Two correlational studies were conducted with Polish participants, using measures of identity fusion, group identification, willingness to fight and die for ingroup members and readiness to deny group’s wrongdoing.

Results

We replicate and extend previous findings by showing that fusion with the country also predicts endorsement of extreme pro-ingroup behaviors with Polish participants (Study 1). Interestingly, fusion with religious group predicts willingness to endorse pro-ingroup behaviors for the religion they practice (Study 2). In addition, the present research shows that strongly fused participants display high levels of readiness to deny the group’s wrongdoing, when the target group is the country (Study 1) or religious group (Study 2).

Conclusions

These findings replicate and extend previous research and are a valuable contribution to the identity fusion theory.
Functioning of memory and attention processes in children with intelligence below average
Authors: Borkowska Aneta Rita , Ozimek Anna
Published: June 2014

BACKGROUND

The aim of the research was to assess memorization and recall of logically connected and unconnected material, coded graphically and linguistically, and the ability to focus attention, in a group of children with intelligence below average, compared to children with average intelligence.

PARTICIPANTS AND PROCEDURE

The study group included 27 children with intelligence below average. The control group consisted of 29 individuals. All of them were examined using the authors’ experimental trials and the TUS test (Attention and Perceptiveness Test).

RESULTS

Children with intelligence below average memorized significantly less information contained in the logical material, demonstrated lower ability to memorize the visual material, memorized significantly fewer words in the verbal material learning task, achieved lower results in such indicators of the visual attention process pace as the number of omissions and mistakes, and had a lower pace of perceptual work, compared to children with average intelligence.

CONCLUSIONS

The results confirm that children with intelligence below average have difficulties with memorizing new material, both logically connected and unconnected. The significantly lower capacity of direct memory is independent of modality. The results of the study on the memory process confirm the hypothesis about lower abilities of children with intelligence below average, in terms of concentration, work pace, efficiency and perception.
Homebound instruction for students with chronic illness: reducing risk outside of the box
Authors: Shaw Steven R. , Clyde Michael A. J. , Sarrasin Matthew
Published: June 2014

Students with chronic illness are at risk for a host of academic and social problems. The risk is exacerbated when students are unable to attend school short term or long term due to medical problems. Educators may be able to reduce academic and social risk for students with chronic illness through effective homebound instruction. However, there remain many barriers to effective homebowund instruction. Effective interdisciplinary and community coordination, development of policies, teacher support, inclusion of families, and use of technology can be combined to overcome these barriers and create effective homebound programs and policies. The result is reduced risk for the large and vulnerable population of students with chronic illness.
University students with learning disabilities at the Faculty of Education, Charles University in Prague
Authors: Kucharská Anna
Published: June 2014

BACKGROUND

The paper deals with learning disabilities (LD) of university students in the Czech Republic. The first part describes most common trends in professional care of students with LD in historical context, the second part analyses contemporary situation of support of students with LD during their university studies. Pivotal part of the text describes the situation at Faculty of Education, Charles University in Prague, from the perspective of state LD students, their difficulties and means of possible support.

PARTICIPANTS AND PROCEDURE

Qualitative analysis of functional diagnostics took place in the frame of evidence of 15 students with learning disabilities. Focal point of the functional diagnostics is a structured interview in which an identification of needed modification for studying with specific educational needs of students with LD takes place.

RESULTS

From our analyses it can be stated, that students with LD apply for registration basing on their experience with high school status of a student with SD, or that their decision is influenced by their current study problems or the fact that they went through a modified entrance exam. We have also discovered the fact, that except for the difficulties which result from the type and degree of the disability and which can be compensated by specific approaches, students also need an emotional and social support.

Learning disability is not, however, perceived only as a disadvantage, many students have stated that it has motivated them in their further development.

CONCLUSIONS

Achieved results point to general specifics to the perceived difficulties, to the specifics of the concrete degrees and to the further personal (emotional, social) characteristics of LD students and they support recommended modification for successful studies.
How compare biologics applied for rheumatic disorders?
Authors: J. Kucharz Eugeniusz
Published: June 2014

Leczenie chorych na reumatoidalne zapalenie stawów stanowi ważny problem kliniczny, a wprowadzenie leków biologicznych istotnie zmieniło strategię terapeutyczną. Leki biologiczne zmniejszają nasilenie zapalenia i jego skutków, w tym uszkodzenia strukturalnego stawów. Ze względu na nieliczne badania bezpośrednio porównujące skuteczność leków biologicznych, leki te są porównywane metodami pośrednimi. Nie dostarczają one jednoznacznych wyników i mają liczne ograniczenia. W pracy zestawiono metaanalizy i pośrednie porównania leków biologicznych stosowanych u chorych na reumatoidalne zapalenie stawów.
LEVANTAMENTO TOPOGRÁFICO: MODELAGEM MATEMÁTICA SOBRE ÁREAS E VOLUMES NA AGRIMENSURA
Authors: Oliveira Ana Maria Libório , Santos Marly Evangelista , Alves Sammya Christina Oliveira
Published: June 2014

O presente artigo tem como objetivo apresentar os resultados parciais da pesquisa desenvolvida no Curso de Pós-Graduação Lato Sensu em Ensino de Ciências e Matemática, o projeto faz a interação da Modelagem Matemática no que tange aos levantamentos topográficos executados na Agrimensura para os alunos do 3º ano Técnico Integrado de Edificações do Instituto Federal de Goiás – campus Jataí. A metodologia, inicialmente, utilizou-se de uma análise qualitativa com pesquisa-ação, demonstração topográfica (Modelagem Matemática), utilização de imagens gráficas, questionários, exemplificações e intervenções. A pesquisa destina-se aos alunos do curso técnico de Edificações por se tratar de um curso que tem na sua grade curricular a matéria de topografia, mas não possui um estudo mais minucioso na análise topográfica e correlações disciplinares, sendo assim apresentando o Modelo Matemático.
CONCEPÇÕES AVALIATIVAS DE PROFESSORES DE CIÊNCIAS E ALUNOS DE UM COLÉGIO ESTADUAL EM JATAÍ-GO
Authors: Vilela-Ribeiro Eveline Borges , De Sousa Maria Helena
Published: June 2014

A tendência educacional brasileira de democratização do acesso à escola cria algumas contradições na própria educação: todos devem ter acesso, entretanto, não são oferecidas condições de equidade para que os mesmos permaneçam na escola e tirem bom proveito dela. No centro desse processo de democratização à educação está a avaliação, que quando realizada de forma errônea e ainda aliada a uma prática pedagógica desprovida de boa vontade e dedicação leva a uma educação de qualidade aquém da desejada. Nesse contexto, o objetivo deste trabalho é investigar as concepções de alunos e professores de ciências (Matemática, Física, Química e Biologia) de Ensino Médio de um colégio estadual na cidade de Jataí-GO sobre avaliação e perceber como a mesma está presente no cotidiano escolar. No contexto do trabalho percebeu-se que os professores e alunos ainda apresentam uma visão clássica sobre avaliação e que enfrentam os problemas comumente citados por professores das redes públicas de ensino, que são baixos salários, falta de estrutura e altas cargas horárias. Entretanto, os professores apresentam aceitação das idéias sobre a avaliação reflexiva-crítica, precisando apenas ser estimulados de alguma forma para possuírem uma prática pedagógica crítica.