bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Simulation Analysis of Coal Mining with Paste-like Backfill under Water Based on UDEC
Authors: Dong Yu , Wu Yang , Shao Lei Chang , Duan Zhong Jie
Published: June 2014

Based on the instance of extremely thick coal seam mining under aquifer in Gonggeyingzi Coal Mine, the theoretical calculation for the height of water flowing fracture zone in this coal mine was 30.6m and calculation model was established. Analyzed by the UDEC software, the surface displacement of backfill mining was 1532mm and the height of overburden rock plastic zone was 36.5m. Compared with 135m away from coal roof to aquifer, slicing backfill mining under aquifer was confirmed to be safe and feasible based on the theoretical calculation and analysis of UDEC. The results provided the basis for the safety of extremely thick coal seam mining under aquifer in this coal mine.
Dynamics of Phase Transformation in Cu-Ni-Be Wedge Copper Alloy
Authors: Wu Cong Yue , Wang Xiao , She Kai , Xie Chun Sheng
Published: June 2014

This paper aims at doing research on the variation of volume fraction of precipitation. And Avrami empirical equation characterizing the relationship between transformation ratios and ageing time is established. This research was carried out by measuring the electric conductivity of Cu-Ni-Be wedge copper alloy after ageing treatment, and analyzing the relationship between electric conductivity and volume fraction of precipitations. Consequently, the equation between electric conductivity and the ageing time is fixed. Then S-curves of the dynamics of phase dynamics of phase transformation and C-curves of isothermal transformation for the Cu-Ni-Be wedge copper alloy are derived.
Effects of Solid Fractions in a Slurry Casting Process on Shrinkage and Microstructure of 7075 Aluminum Alloy
Authors: Rattanadakul Sureebhorn , Wannasin Jessada , Janudom Somjai , Plookphol Thawatchai , Wisutmethangoon Sirikul
Published: June 2014

Effects of Gas Induce Semi Solid (GISS) on shrinkage porosity of 7075 aluminum alloy were investigated. Initial solid fractions were controlled by rheocasting time at 5, 10 and 15 seconds and 4 and 6 bar of gas pressure. The results showed that the initial solid fractions were increased by increasing rheocasting time and gas pressure. As for the shrinkage, values of the GISS process samples were lower than those of the conventional process samples. In addition, the shrinkage areas of semi solid samples were decreased by increasing the initial solid fractions. The microstructure of semi solid samples was shown to be uniform globular grains along the samples.
Beneficiation of a Low-Grade Refractory Copper Ore in Yunnan
Authors: Xie Feng , Zhang Han Ping , Chen Xian Mei , Lv Jin Fang
Published: June 2014

Regarding to a Low-grade refractor copper ore，this paper investigates the property of run-of-mine ore，and based on the characteristic of raw ore，mineral process experimental study is implemented. It can realize the copper concentrate grading at 15.84%with a 87.04% recovery through the bulk flotation with Cu-S separation process.
Study on M5640 Extraction Copper from Ammoniac Leach Solution of Copper Oxidized Ore
Authors: Mao Ying Bo , Wei Zhi Cong , Fang Jian Jun , Zhang Tie Min , Jiang Tai Guo
Published: June 2014

The extractant M5640 that extracted and stripped copper in the ammonia leach solution of copper oxidized ores solution of were mainly studied for the experimentation examined the M5640 concentration, phase ratio, extraction time, and liquid pH. Laboratory Investigations indicated that M5640 is really an efficient copper extractant with a maximum extraction of as high as 99.64% under the conditions of 6.48g/L Cu in leach solution, the extraction agent concentration is 10%, phase ratio is 1:1, extraction time is 2 min and liquid pH was 9.58. The stripping can be conducted with the barren electrolyte as a stripping agent in which the sulfuric acid concentration remains about 150g/L, and a stripping rate of 99.80% is obtained.
Unconstrained Surface Directional Rolling Process Optimization of Self-Lubricating Spherical Plain Bearing’s Integral Outer Ring
Authors: Ma Chun Rong , Yang Yu Lin , Chen Ji Gang , Cui Lin Lin , Zhang Xiao Tian
Published: June 2014

Self-lubricating bearings are the basic components of the aviation industry, and the precision forming process of bearings is one of the kernel technologies, which is urgent to be self-developed. A method called unconstrained surface directional rolling process was put forward, and then the flow chart of process optimization was designed. Based on the numerical analysis model of rolling process, Latin hypercube sampling method was used for the design-space analysis. By using BPF+NSGA-II and Kriging+PSO algorithms, the rolling process was simulated and optimized, and then the results were verified by experiments. Study shows that by the use of the new proposed process and the optimization methods, the products can get a higher quality; results of optimization and experiments are valid and consistent, comparing with BPF+NSGA-II algorithm, results of Kriging+PSO algorithm are slightly better.
Dynamic Buckling of Bars under Step Load Based on Semi-Analytic Method
Authors: Che Hui , Yang Qiang , Han Zhi Jun , Lu Guo Yun
Published: June 2014

Dynamic buckling of bars under step load was studied by considering the stress wave effect. Straight bars without axial inertia were taken as an example when deformation was small. The buckling solution satisfying the boundary conditions was given by the semi-analytic method. The buckling solution was substituted to the dynamic buckling governing equations. The unified expression of dynamic buckling critical load was obtained by discussing the character of the solution. The dynamic buckling critical load was obtained by calculating the value of when the stress wave propagated to the critical length . The value of dynamic buckling load was 2.5 times the one’s of static buckling load with corresponding equivalent length.
Boron Removal from MG-Si by Slag Treatment with Copper Addition
Authors: Chen Rong Yi , Yang Xiao Bing , Chen Rui Zhi , Qiu Shi , Gan Chuan Hai , Zeng Xue , Li Jin Tang , Luo Xue Tao
Published: June 2014

The effect of slag treatment with Copper addition in silicon purification by metallurgical methods was examined in this paper. The microstructures and contents of Si-Cu alloy after slag refining were investigated by XRD and ICP, respectively. The majority phases in the Si-Cu alloy were Cu3Si and Si. The partition ratio of boron (LB) between slag and silicon was studied with and without Cu addition. Experimental results show that slag treatment with Cu addition can improve the LBin CaO-SiO2-CaF2slag system, where a maximum boron removal ratio of 85% could be achieved.
Synthesis and Characterization of Polythiophene / SBA-15 Composite
Authors: Hou Qin Qin
Published: June 2014

A new nanocomposite, semiconducting polythiophene (PT) confined in mesoporous silica (SBA-15) was synthesized. PT was formed in the pores of SBA-15 by subsequent oxidative polymerization with FeCl3. Different techniques were used to characterize the nanocomposite formation. X-ray diffraction (XRD) and N2 adsorption/desorption analysis showed that the nanocomposite possesses mesoporous structure, and the residual pore volume of nanocomposite was significantly lower than that of pure empty SBA-15. Scan electron micrographs confirmed the presence of polythiophene inside pore channels of the host, and thermogravimetric analysis proved confinement effect in the channel system.
Effect of Si Content on Microstructure and Properties of 60Si2CrVA Spring Steel
Authors: Zhao Fei , Zhang Zhan Ling , Li Jun Shuai , Ye Cui , Li Ni
Published: June 2014

The microstructure and mechanical properties of the four spring steels with different Si content treated by Q-I-Q-T process were studied by metallographic microscope, MTS, impact testing machine and X-ray stress analyzer. The results show that the tensile strength and yield strength is first increased and then decreased with the increase of Si content, the volume fraction of retained austenite and elongation are fist decreased and then increased when the Si content is less than 2.1%, and the microstructure become finer and homogeneous. When Si content reaches 2.1%, the comprehensive properties of 60Si2CrVA spring steel is the best.
Non-Linear Numerical Simulation on Mechanical Behaviour of Steel Reinforced Concrete (SRC) Columns
Authors: Wang Cheng Quan , Shen Yong Gang , Chen Dong Qiang
Published: June 2014

In order to study the mechanics properties to of concrete columns with embedded steel, analysis models of SRC columns are established by using finite element software ABAQUS. Firstly, in order to validate the rationality of the analytical model, the test specimens are modeled, the results obtained from the finite element and experimental analyses are compared to each other, it is found that the finite element behavior indicates a good agreement with the experimental behavior. Furthermore, the ductility and ultimate capacity of SRC columns are studied with the changes of steel bone ratio and the axial compressive ratio. Analytical results demonstrate that embedded steel improves the ductility of SRC columns with large axial compressive ratio and steel bone ratios have obvious effect on ductility and ultimate capacity of SRC columns. The study results have some value on the design and application of the SRC columns.
Preparation and Mechanical Characterization of Amorphous B-C Films
Authors: Liza Shahira , Akasaka Hiroki , Nakano Masayuki , Ohtake Naoto
Published: June 2014

This study has demonstrated that trimethylboron, B(CH3)3 is a suitable boron source material for the fabrication amorphous boron carbide (a-BC:H) films. a-BC:H films were deposited by pluse plasma chemical vapor deposition on a silicon substrate (100) with different gas pressures and gas flow rates at constant voltage, -5 kV . The grown a-BC:H films were found to be porous surface and their thickness were in the range of 0.95 to 1.56 μm for 3 h of deposition time. Results indicated that the boron contents, morphologies and mechanical properties of the a-BC:H films were dependent on the gas pressures and gas flow rate. The increased of boron content will introduce more porous film surface. The effect of boron content on the mechanical properties such as hardness, Youngs modulus, and wear resistance were discussed. The good quality film is obtained from B(CH3)3 at 5 Pa and gas flow rate of 15 cm3/min which boron to carbon atomic ratio is 0.43. This film has lower friction coefficient (0.3) sliding against stainless steel ball, high hardness (8.1 GPa) and Youngs modulus (62.2 GPa).
The Potential of Quercetin in Psidium guajava L. Leaves Extract as Bioinhibitor for Controlled Released Fertilizer
Authors: Ramli Nur Kamila , Majeed Zahid , Shuib Anis , Mansor Nurlidia , Man Zakaria
Published: June 2014

This study was done to investigates the usage of natural products as one of the materials in fertilizer application. Urease inhibitors that are commonly used in agriculture are usually chemical based which affects the environment. Introducing natural products will ensure biodegradability of the material. Psidium Guajava L. (guava) has been reported to have properties such as antibacterial, anti-oxidant, anti-cancer, and anti ulcer for medical purposes. Guava leaves extract contains an active compound named quercetin that was successfully reported to exhibit significant urease inhibitory activities. Spectrophotometric method was used in this study with the theory of Beers Law in order to measure the changes in ammonia concentration. Small reduction of ammonia (NH3) concentration with different about 0.1 mol/L was calculated and the releasing was almost equal till the end of incubation time. The guava leaves extract prepared showed the potential to reduce the release of NH3 concentration during urea application.
Statistical Analysis of Binder Behavior during Debinding Step in Powder Injection Molding (PIM)
Authors: Chakartnarodom Parinya , Chuankrerkkul Nutthita
Published: June 2014

The aim of this paper is to propose the approach for applying statistical methods (linear regression and statistical hypothesis testing) to study the behavior of binder during binder removing (debinding) step in powder injection molding (PIM) and also the parameters that affect the binder removing rate. In this work, the binder system under the investigation is the composite binder of 85wt% polyethylene glycol (PEG) and 15 wt% poly (methyl methacrylate) (PMMA) where PEG can be removed from the green product by using warm water while PMMA is removed later during sintering. At 0.05 level of significance, the linear regression method and the statistical hypothesis test prove that the dissolution behavior of PEG can be described using Avarami equation. Furthermore, the dissolution rates of PEG were independent of all parameters used in this study including binder contents in the green products, temperatures, and powder sizes.
Investigation of Surface Characteristics of Hydroxyapatite/Titanium Composite Layer Obtained by HF Magnetron Sputtering
Authors: Mamayeva Axaule A. , Panichkin Alexander V. , Aubakirova Rashida K.
Published: June 2014

Calcium phosphate coatings on the VT1-0 titanium substrate were obtained by high-frequency magnetron sputtering technique. Surface morphology, phase and elemental composition of the coatings were investigated by scanning electron microscopy, energy dispersive X-ray analysis and infrared spectroscopy. It was found formation of molecular bonds, those depending on the discharge power and isothermal annealing temperature, are typical for hydroxyapatite and accompanied by changes in the phase and elemental composition. Increase of discharge power up to 250 watt provides denser and thick coatings and promotes the formation of amorphous phase in the higher concentration more than 20%. The ratio of the amorphous and crystalline phases determines the long-term strength of the coatings.
Corrosion Behavior of Soldered and Laser-Welded Ni-Free Co-Cr Alloy Joints in Sodium Chloride Solution
Authors: Eutrirak Piyarach , Srimaneepong Viritpon , Saengkiettiyut Kanokwan
Published: June 2014

This paper investigates the quality and corrosion property of Ni-free Co-Cr alloy joints soldered and laser welded using filler. The soldered and laser-welded test specimens were sectioned at the center and rejoined by either soldering or laser welding using appropriate fillers. The joint area was analyzed using microfocus X-ray and the percentage of porosity, as a measure of joint quality, was calculated. The corrosion behavior of soldered and laser-welded test specimens was evaluated using a potentiodynamic polarization technique in a 0.9 wt.% NaCl solution, pH 2.3, at 37°C. The results indicated that the amount of porosity and cracks in soldered joints were less than those of the laser-welded joints, leading to a lower corrosion rate.
Deposition of Amorphous Boron Carbide Films with Pulsed Magnetron Sputtering and Evaluation of their Mechanical Properties
Authors: Saito Kei , Fujii Ryo , Ohtake Naoto
Published: June 2014

Amorphous boron carbide films were deposited with pulsed magnetron sputtering using a sintered B4C target with Ar as the processing gas, and the chemical components, structure, and mechanical properties of the films were investigated. To deposit amorphous boron carbide films using a B4C target, a pulsed power supply (14.4 kHz) was employed. Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) were used to characterize the chemical compositions and structure of the films. According to the results of XPS, the B/C ratio in the films synthesized with pulsed magnetron sputtering was 2.21. Nanoindentation tests and ball-on-disk (BoD) tests were performed to evaluate the mechanical properties. It was found that the films deposited by pulsed magnetron sputtering had an average hardness of 32.1 GPa and an average Youngs modulus of 235.1 GPa.
Uncured Properties of Silica Filled ENR Compounds at High Temperature Curing
Authors: Kamal Mazlina Mustapha , Zakaria Muhammad Zahid
Published: June 2014

Rubber reinforcement in general depends on the type of filler used in the rubber mixture. Instead of carbon black, Silica filler has been widely accepted in tyre making due to its low rolling resistance property. In recent years, there is a trend in using higher curing temperature in order to improve productivity of vulcanisation line without drawbacks in the performance of tyres. In this work, effect of vulcanisation temperature based on the silica filled ENR curing behaviour was studied. Results indicate that time-dependant reversion behaviour of ENR was similar to that of unmodified Natural Rubber. The physical properties slowly deteriorated as the curing temperature approached 180°C which related to low crosslink density. Carbon Black filled ENR compound was used as a comparison.
Processability Behaviour of Dual Filler Systems Reinforced Epoxised Natural Rubber
Authors: Zaeimoedin Teku Zakwan , Kamal Mazlina Mustapha
Published: June 2014

Rheological studies of polymers are of great importance in optimizing the processing conditions and in designing processing equipments like injection molding machines, extruders, and dies required for various products. Melt rheological studies give us valuable viscosity data that will be helpful in optimizing the processing conditions. Parameters like melt viscosity as a function of shear rate or shear stress and temperature have become more and more important. Previous study indicated that the flow behaviour of the compound depends on the filler loading. Lesser elastic torque was found with compound containing lower filler content as compared to higher filler content. In this work, effect of dual filler, based on Carbon Black / Silica filled Epoxidised Natural Rubber (ENR) compound was investigated. A total of 80phr of filler content based on passenger tyre tread formulation was used in the experiment. The compounds were prepared by melt mixing in tangential type of an internal mixer. The rheological and the processability properties of the compounds were determined using three different testing instruments namely Capillary Rheometer, Mooney viscometer and Rubber Process Analyzer (RPA). A variation of shear rates (ranging from low to high) was performed, in order to better reflect the actual processing condition in rubber manufacturing. It was found that ENR mix with ratio silica to carbon black 70:10 exhibited the best flow behaviour and processability properties as compared to control and other mixes.
Simulation of Dirac Tunneling Current of an Armchair Graphene Nanoribbon-Based P-N Junction Using a Transfer Matrix Method
Authors: Suhendi Endi , Syariati Rifky , Noor Fatimah A. , Kurniasih Neny , Khairurrijal Khairurrijal
Published: June 2014

We have studied tunneling current in a p-n junction based on armchair graphene nanoribbon (AGNR) by using the relativistic Dirac equation and a transfer matrix method (TMM). The electron wave function was derived by solving the relativistic Dirac equation. The TMM, which is a numerical approach, was used to calculate electron transmittance and the tunneling current. The results showed that the tunneling current increases with the bias voltage. On the other hand, the tunneling current increases with the decreases in the electron incidence angle and temperature. Moreover, the increases in the AGNR width and electric field in the p-n junction result in the increase in the tunneling current.
Electrical Coupling of Organic/Inorganic Semiconductor Interfaces: A Comparative Study
Authors: Dhingra Mansi , Shrivastava Sadhna , Senthil Kumar P. , Annapoorni S.
Published: June 2014

The present work attempts to investigate the interfacial phenomenon occurring between two dissimilar materials and in particular organic and inorganic hybrid materials. Layer by layer hybrid heterostructures are fabricated by electro-deposition technique. Here, ZnO thin films are deposited using potentiostatic mode using regulated DC voltage supply fixed at-1.0 V (with respect to the reference electrode) with platinum sheet (99.99% purity) used as the counter electrode and ITO-coated glass used as a working electrode. The as obtained ZnO films are then used as substrates for deposition of organic layer. Two conducting polymers namely polyaniline (PANI) and polypyrrole (PPy) are deposited by electro-deposition method on ZnO to form ZnO/PANI and ZnO/PPy interfaces. The two interfaces are compared for their photoconducting response. These studies are further correlated with the properties that the two interfaces share.
Green Nanoparticle Oil Well Cement from Agro Waste Rice Husk Ash
Authors: Alias N. , Nawang M.M.M. , Ghazali N.A. , Mohd T.A.T. , Manaf S.F.A. , Sauki A. , Shahruddin M.Z. , Ramlee N.A.
Published: June 2014

Cement is an important part in oil and gas well completion. A high quality of cement is required to seal hydraulic pressure between casing and borehole formation. Cement additives were used to enhance the cement properties such as thickening time, compressive strength, porosity and permeability of the cement. Currently, the commercial additives were imported and the price is keep increasing year by year. Therefore, the researchers were continuously looking for potential additives such as nanoparticle to improve the cement properties. This paper presents the effect nanosilica on compressive strength and porosity of oil well cement type G. In this study, two type of nanosilica were used, synthesis nanosilica from rice husk ash (RHA) and commercial nanosilica. The synthesized nanosilica was characterized using fourier transform infrared spectroscopy (FTIR), X-ray flouresece (XRF) and Field Emission Scanning Electron Microscopy (FESEM). All the experiments were conducted using API standard procedures and specifications. Based on the results, compressive strength of cement slurries was improved from 2600 psi to 2800 psi for 8-hours curing, when the amount of nanosilica increased from 0 wt% to 1.5 wt%. Besides that, incorporation of nanosilica from RHA into cement formulation resulted in reduction of cement porosity up to 18 % pore volume. Overall, the results showed that the incorporation of nanosilica from RHA improved the oil well cement compressive strength and oil well cement porosity. In conclusion, green nanosilica from RHA can be a potential candidate to replace the commercial nanosilica to enhance the oil well cement properties as well as to prevent the migration of undesirable fluid which can lead to major blowout.
Analysis of Elastic-Plastic Responses of a Water Tower Structure during an Earthquake Based on the Transfer Matrix Method of Multibody System
Authors: Huang Hui Jia , Ding Jian Guo , Qiao Zhi
Published: June 2014

As a member of the city life lines, water towers are still widely used as an outdoor device to supply water. Study on the seismic performance of the water tower is of great significance because earthquakes often happen in China. Finite element methods, such as the ANSYS, are widely used as traditional structural dynamic analysis methods, but the calculation efficiency of the ANSYS is very low. In this paper, the transfer matrix method of multibody system (MS-TMM) was introduced to analyze the seismic performance of a water tower. Based on the example as a water tower, the calculation speed of the MS-TMM is much faster than the calculation speed of the ANSYS and the responses obtained by the MS-TMM are nearly equivalent to the responses obtained by the ANSYS. Evidently, the MS-TMM can satisfy the requirements of calculation efficiency and calculation accuracy in computing the responses of water towers during earthquakes.
Gas Lift Optimization of an Oil Field in Malaysia
Authors: Ghazali Nurul Aimi , Mohd T.A.T. , Alias N. , Yahya E. , Shahruddin M.Z. , Azizi A. , Fazil A.Y.
Published: June 2014

Gas lift is an artificial lift method which is commonly used in offshore operation with sufficient gas sources as it consumes minimum space on the platform. Gas lift operates by injecting a high pressure gas down through the tubing casing annulus of a well and the injected gas enters the tubing through a gas lift valve installed on the tubing. Gas lift increases production by two means, density reduction of oil column inside the tubing so that the flowing bottom-hole pressure which is affected by the hydrostatic pressure of the fluid column is reduced and by providing external energy to the oil as the gas expends.Reducing the bottom-hole pressure will improve the drawdown of the well. A production well is modelled by using a production modelling program, Integrated Production Modeling (IPM) Prosper to analyze the production performance at various conditions. A base case model is developed from the production data of an actual oil field to simulate the performance of the actual well without gas lift system. Later, the gas lift is added to the model and the performance was compared with the base case model. The gas parameter was also studied to determine the optimum injection gas condition for maximum oil production. The gas injected at 1490m can be achieved by injecting the gas with 1200 psi, l300 psi or 1400 psi. However, the optimum gas injection pressure was determined to be at 1400 psi as the design shows that the required unloading stage is the least. The optimum gas injection rate was determined at 5 MMscf/d with the estimated net revenue is the highest. For injection gas gravity, the lighter gas was determined to be the optimum selection since it gives significant reduction of FBHP (Flowing Bottom Hole Pressure) with less hydrostatic pressure inside the tubing column.
The Study of Bone Cutting Force with FEM
Authors: Liu Sen , Wu Dong Mei , Zhao Jun
Published: June 2014

In orthopedic surgery, it is easy to do harm to surrounding tissues, so the study of bone cutting is necessary. In this article, a finite element model (FEM) of orthogonal bone cutting is developed. Cutting force intra-operatively can provide the surgeon with additional on-line information to support him to control quality of cutting surface. The obtained cutting force decreased little with cutting speed increasing, but ascended evidently with cutting depth increasing. The results of finite element simulations are aimed at providing optimization of cutting parameters and the basic information for hybrid force-velocity control of a robot-assisted bone milling system.
A Simple GA Based Approach for Multi-Objective Optimization of Machining Parameters
Authors: Waseem Akhtar , Su Jian Fei , Chen Wu Yi , Sun Peng Fei
Published: June 2014

A simple approach to multi-objective optimization of machining parameters is presented. Regression analysis of experimental data is carried out to obtain the correlation between cutting parameters and response variables. Finally, Genetic Algorithm (GA) toolbox of MATLAB is used to carry out multi-objective optimization of two objective functions (surface roughness “Ra” & material removal rate “MRR”). Genetic algorithm is found to be a powerful tool for multi-objective optimization of machining parameters in this study.
Effect of Calcination Temperature on the Morphology of Carbon Nanosphere Synthesized from Polymethylmethacrylate
Authors: Al-Ahmadi Abdullah F. , Al-Daous Mohammed A. , Saleh Tawfik A.
Published: June 2014

In this work, hollow carbon nanospheres (HCNs) were synthesized by carbonizing core/shell particles of polymethylmethacrylate (PMMA)/ resorcinol formaldehyde. The core/shell particles were prepared using emulsion polymerization; polymethylmethacrylate as a template and resorcinol-formaldehyde polymer as the carbon source. Spheres were first synthesized by batch mode polymerization and then the shell was polymerized on the surface of the spheres. The composite was stabilized, and then carbonized. The effect of calcination temperature was investigated in the range between 200-500 oC. Scanning electron microscopy (SEM), energy-dispersive X-ray spectrometer (EDX), Raman and Fourier transform infrared (FTIR) were used for characterization of the resulting carbon.
Preparation of Layered Double Hydroxide and its Graphene Composite Films as Electrodes for Photoelectrochemical Cells
Authors: Azuma S. , Kawamura G. , Muto Hiroyuki , Kakuta Noriyoshi , Matsuda Atsunori
Published: June 2014

Visible-light responsive photoanodes for water splitting into hydrogen and oxygen were fabricated via NiTi-layered double hydroxide (NiTi-LDH, [Ni1-xTix(OH)2]2x+(An-)2x/n・mH2O]) and NiTi-LDH/graphene composite prepared by homogeneous precipitation methods. The NiTi-LDH and NiTi-LDH/graphene films were formed on transparent fluorine-doped tin oxide (FTO) glass substrates by electrophoretic deposition (EPD). The EPD films showed the pattern of hydrotalcite structure under x-ray diffraction, indicating that NiTi-LDH has been deposited on FTO by EPD without degradation. NiTi-LDH powder was obtained from formic acid intercalated LDH by homogeneous precipitation in formamide with hexamethylenetetramine, and NiTi-LDH/graphene composite was obtained from graphene and NiTi-LDH aqueous suspension with urea. The formed NiTi-LDH and NiTi-LDH/graphene composite films have different morphologies. Both NiTi-LDH and NiTi-LDH/graphene films prepared showed photovoltage of 15-55 mV under visible-light irradiation. Their photoelectrochemical properties were affected by the film morphology.
Microstructure and Properties of Aluminum-Copper Composites Prepared by Hot-Pressure Sintering
Authors: Zhang Lian Meng , Zhou Xiao Zhuang , Luo Guo Qiang , Chen Ping An , Shen Qiang , Wang Chuang Bin
Published: June 2014

Aluminum (Al) and Copper (Cu) have been used in graded density impactors. Al-Cu composites with different compositions have been prepared by hot pressing sintering. Intermetallic compounds were produced when the temperature was above 723 K, while they can’t be found at the temperature of 723 K. The relative density of Al-Cu composites from pure Al to pure Cu consolidated at 723K all exceeded 98.5%. The optimum sintering conditions were then determined to sintering temperature of 723 K, uniaxial pressure of 100 MPa, and duration time of 2 h. Al and Cu were mixed homogeneously and well compacted, and no obvious pores were found. The thickness of diffusion layer between Al and Cu was very thin, only about 0.6 μm. The wave impedance values increased almost linearly from 16.98×106to 40.66×106kg/m2·s with increasing Cu content in Al-Cu composite from 0 to 100 vol.%, which was well consistence with the values calculated according to the rule of mixtures. The elastic modulus of different compositions matched well with the theoretical model of Voigt and Reuss. Highly densified Al-Cu composites without intermetallic compounds were successfully prepared using hot-pressure sintering, which was the basis of fabricating Al-Cu system graded density impactors.
Synthesis and Evaluation of Fe Nanowire and Nanorod by Electro-Chemical Process
Authors: Nakahira Atsushi , Yamamoto Shinya , Onodera Hiroshi
Published: June 2014

Nanoporous structured alumina templates for the synthesis of Fe nanowires were synthesized by the anodization of aluminium metal under various synthetic conditions in some acid solutions. Subsequently, using this nanoporous structured alumina as a template, Fe nanowires with some tens nanometer in diameter and some micron in length was successfully synthesized by both electrodeposition process into various types of porous alumina templates and chemical treatments in mixed-acid solutions to remove the templates. Effects of anodization treatments of aluminium for a porous template on the microstructure of Fe nanowires and nanorods were examined. As a result, the morphology of Fe products obtained by electrodeposition process could be designed with the template obtained under the synthetic conditions (anodization temperatures and electrodeposition conditions etc).
Microstructural Analysis of Biomedical Co-Cr-Mo Alloy Subjected to High-Pressure Torsion Processing
Authors: Isik Murat , Niinomi Mitsuo , Cho Ken , Nakai Masaaki , Hieda Junko , Yilmazer Hakan , Horita Zen Ji , Narushima Takayuki
Published: June 2014

The effect of high-pressure torsion (HPT) processing on the microstructure and Vickers hardness of Co-Cr-Mo (CCM) alloys were investigated in this study. The microstructure of initial CCM alloy contains equiaxed grains with a grain diameter of approximately 50 μm and twins. The clear grain boundaries of equiaxed grains and twins disappear after HPT processing at a rotation number, N, of 10. The phase maps of initial CCM alloy and CCM alloy subjected to HPT processing at N = 5 measured by electron backscatter diffraction exhibit that the ratio of γ phase decreases from 93.5% to 34.1% and the ratio of ε phase increases from 6.5% to 65.9% by applying HPT processing. These results indicate that the ε phase is formed by high-strain, which is induced by the HPT processing. The Vickers hardness values on the surfaces of the CCM alloys subjected to HPT processing at N = 1, 5, and 10 increase with increasing the equivalent strain, εeq. These results suggest that an increase of Vickers hardness is correlated to an increase of the ratio of ε phase and the dislocation density, and grain refinement, which are caused by the high-strain induced by HPT processing.
Effect of Al Thin Film on Microstructure and Mechanical Properties of Diffusion-Bonded LY12/TC4 Joints
Authors: Luo Qiang Guo , Hu Xue Shu , Shen Qiang , Zhang Lian Meng
Published: June 2014

LY12/TC4 joints have wide applications in many industrial areas such as aerospace, nuclear and chemical industries. In the present study, TC4 alloy and LY12 alloy with and without aluminum thin film was produced under low temperature of 380 oC. The microstructure and mechanical properties of the joints were investigated. The addition of the Al thin interlayer had largely improved the interfacial microstructure and shear strength of the joints. The average shear strength of LY12/Al/TC4 joints was 64.3 MPa which was 2.5 times larger than the LY12/TC4 joints’ strength. The shear fracture mainly occurred on the interface of LY12 and TC4 from the XRD result of fracture surfaces.
Preparation of Zirconium Phosphate Bonded Silicon Nitride Ceramic Coatings by Cold Spray and Presureless Sintering
Authors: Chen Fei , Li Fei Yu , Shen Qiang , Zhang Lian Meng
Published: June 2014

In the present study, a new method for preparing zirconium phosphate bonded silicon nitride (Si3N4) ceramic coatings with low porosity was developed using cold spray and pressureless sintering technique. Zirconium phosphate (ZrP2O7) was used as a binder material instead of the traditional organic materials, in order to prevent the residual carbon which was severe to the dielectric properties of the Si3N4ceramics. Firstly, aqueous Si3N4slurries with 0~40 wt.% solid loading were prepared, using deionized water as the liquid medium. Then the Si3N4slurries were cold sprayed on the Si3N4porous ceramic substrates and finally the samples were presurelessly sintered at 1000oC to achieve the Si3N4ceramic coatings. The rheological properties and viscosity of Si3N4slurries were investigated in detail, as a function of solid loading. The optimum cold spray parameters were spray distance 21 cm and spray time 20 s. The porosity of the obtained Si3N4ceramic coating was ~5 % and the interface between the coating and substrate was well bonded, without microcracks, indicating a good thermal physical match between the coating and substrate.
API 11D1/ISO 14310 Grade V0 Qualified Ultra-HPHT Permanent Production Packer
Authors: Taylor Robert , Doane James , Anderson Gary , Deng Guijun , Collins Scott , Ansohn Travis
Published: June 2014

Ever-increasing global demand for hydrocarbons challenges the oil and gas industry to explore and develop deeper and hotter reservoirs, pushing the boundaries of completion equipment capabilities from the traditional high pressure high temperature (HPHT) environment (15,000 to 20,000 psi and 350–450°F) to the ultra-HPHT environment (>20,000 psi and >450°F). Ultra-HPHT wells are being actively drilled in the Gulf of Mexico (GOM) region, on the shelf and in deep water. Great efforts are being made throughout the industry to develop safe and reliable completion tools qualified for ultra-HPHT conditions.

The paper continues the work of previous papers, SPE 159182 and IPTC 16852. In SPE 159182, the focus was on the technological breakthrough of an ultra-HPHT seal system (500°F and 25,000 psi); IPTC 16852 addressed how an ultra-HPHT permanent production packer (470°F and 20,000 psi) was developed to meet technological challenges in as-rolled casing. This paper presents the design validation of an API 11D1/ISO 14310 grade V0-qualified ultra-HPHT permanent production packer (470°F and 20,000 psi), and also how supplemental qualification testing for a specific application by a customized fit-for-purpose test was tailored to test aspects of the unique seal design. The packer successfully passed both the API11D1/ISO14310 grade V0 test and the fit-for-purpose test.
Big Bend map-area, British Columbia, 82M (east half)
Authors: Wheeler J O
Published: June 2014

Monashee Mountains in the western half of the map-area are underlain by the Shuswap Metamorphic Complex. Selkirk Mountains, in the eastern half of the area, comprise Proterozoic clastic rocks and minor limestone of the Horsethief Creek Group, Lower Cambrian
quartzite and greenstone of the Hamill Group and limestone of the Badshot Formation, Lower Cambrian and later clastic rocks of the Lardeau Group, and several granitic stocks. Cambrian sediments of the Rocky Mountains occur in the northeasternmost corner of the map-area. The Shuswap Complex is
featured by a gneiss dome centred near Frenchman Cap. Granitic gneisses in the core of the dome are surrounded by successive envelopes: an inner zone of paragneiss, schist, and quartzite; a central zone of paragneiss and abundant pegmatite; and an outer zone of granitic gneiss and pegmatite. The
dome is characterized by northwest-trending folds of variable plunge that have increasingly flatter west-dipping axial planes towards the eastern margin of the dome. Such folds were superimposed upon apparently earlier westerly trending, attenuated, recumbent folds. In the western Selkirks, opposite
the gneiss dome, northwesterly trending structures are overturned to the southwest with increasing intensity of deformation towards the dome. Such structures were superimposed upon apparently earlier attenuated, recumbent folds with northeasterly and easterly trending axes. Structures in the
northeastern Selkirks, developed in Proterozoic rocks metamorphosed to almandine-amphibolite facies, are overturned northeastward. Lead-zinc sulphides are commonly associated with limestones of the Badshot Formation and in the lower part of the Lardeau Group and with the impure marbles of the inner
zone surrounding the core of the gneiss dome.
The Ilgachuz Range and adjacent parts of the Interior Plateau, British Columbia
Authors: Souther J G , Souther M E K
Published: June 2014

Christensen Creek (93C/11) and Carnlick Creek (93C/14) map areas encompass the Ilgachuz Range, a highly dissected late Tertiary shield volcano that rises 1200 m above the general level of the Interior Plateau of central British Columbia. The drift-covered plateau
surface adjacent to the Ilgachuz Range contains isolated exposures of Mesozoic volcanic and sedimentary rocks, early Tertiary felsic volcanic and subvolcanic rocks, and mylonitic orthogneiss of the Eocene Tatla Lake Metamorphic Core Complex. Undeformed late Tertiary volcanic rocks rest unconformably
on all of the older strata. They include Chilcotin Group basalt flows and Ilgachuz Group alkaline volcanic and subvolcanic rocks which form the Ilgachuz Range shield volcano. The Ilgachuz Range is a composite volcanic shield comprising a thick lower section of highly alkaline to peralkaline felsic
flows, domes, and hypabyssal intrusions, overlain by a relatively thin veneer of alkaline basalt. A small central caldera is filled with pyroclastic deposits, lacustrine beds, and ponded lava. K-Ar dates indicate that the entire volcanic edifice was built between 6 Ma and 4 Ma. The Ilgachuz Range
is one of three large shield volcanoes in the central part of the east-trending Anahim Volcanic Belt. Volcanoes along this belt become progressively younger from west to east and are believed to have formed on the American continental plate as it moved westward over a mantle hotspot. The chemistry
and stratigraphy of the Ilgachuz Group rocks suggest that they are the product of crustal melting and crystal fractionation, accompanied by underplating with mantle-derived basaltic magma.
Who is Theophilus? Discovering the original reader of Luke-Acts
Authors: Creamer Jennifer M. , Spencer Aida B. , Viljoen Francois P.
Published: June 2014

The aim of this article is to investigate the nature of Theophilus as the original reader of Luke-Acts. A lexical and grammatical analysis of Luke 1:1–4 and of the broader literary context of the Luke-Acts narrative provided the basis for discovering the identity of Theophilus. This article proposes that Theophilus was a man of prominent position: a Gentile who had received some introductory teachings about Christ and who needed factual verification of the events surrounding the emergence of Christianity. Die doel van hierdie artikel is om Theophilus, as die oorspronklike leser van Lukas-Handelinge, se identiteit te ondersoek. ’n Leksikale en grammatikale ontleding van Lukas 1:1–4, asook ’n ontleding van die breër literêre konteks van die Lukas-Handelinge-narratief, bied die basis vir die ontdekking van Theophilus se identiteit. Hierdie artikel stel Theophilus voor as ’n man met ’n prominente posisie: ’n nie-Jood wat basiese Christusonderrig ontvang het en wat die bevestiging van die gebeure rondom die opkoms van die Christendom voorop gestel het.
Effects of different desensitizing agents on bleaching treatments
Authors: Po Lam Hoi , Wilson Nairn
Published: June 2014

The objective of this paper was to bring together and summarize the available information on the effects of different desensitizing agents on bleaching treatments. Information from all scientific papers and reviews identified in the Institute for Scientific Information Web of Science and PubMed using the search terms: Bleaching, whitening, brightening or color and desensitizing, fluoride, potassium nitrate, or amorphous calcium phosphate was included in the data collected and synthesized to produce the summary of findings and recommendations. The use of desensitizing agents in bleaching treatments may limit or control sensitivity, promote remineralization, increase enamel microhardness, and enhance the efficacy of the bleaching treatment. The use of desensitizing agents may exert a positive influence on the outcome of bleaching treatments.
A survey to access knowledge and practice among dentists regarding local anesthetic dosage in three cities of Uttarakhand
Authors: Kaira Laxman Singh , Dabral Esha
Published: June 2014

Objective: Local anesthetics are the most commonly used drugs in routine dentistry. Although they are considered effective and safe in controlling pain during dental procedures, complications related to their use appear inevitable. Many dentists use these drugs routinely but are unaware of the dose calculations required and the maximum safe and effective dose of the drug. Materials and Methods: This study was aimed to determine the knowledge that general dental practitioners and dental specialists, in three different cities in India, have regarding dose calculations and the maximum-dose required of the most commonly used local anesthetics. A one page survey questionnaire was used in this study and data were analyzed using standard SPSS statistical program version 11, software (SPSS Inc. Chicago, Illinois, USA). Results: The respondents comprised 71.4% general dental practitioners and 28.5% dental specialists, with ages ranging from 26 to 50 years; Nearly 75% of the total respondent was males and 25% females. Nearly 69% of the respondents were unaware of the maximum recommended dose for use on adult, healthy patients and 81% were still confused about the maximum numbers of syringes containing 2% lignocaine with adrenaline that can be given to a patient. A total of 49% of general dental practitioners and specialists do not perform aspiration when injecting local anesthetics, whereas only 38% performed the aspiration in inferior nerve block technique, while only 12% performed aspiration in all types of injection techniques. A high percentage of the dentists (84%) who responded are unaware of how to calculate the local anesthetic dose and 31% of them encountered complications during, or after, local anesthetic administration. Conclusion: General practitioners and dental specialists appear to have an inadequate knowledge about local anesthetics maximum-dose and dose calculations; further educational courses are recommended to update them regarding such important aspects of dentistry.
Knowledge of dental practitioners on the management of oral conditions in pregnancy in South Nigeria
Authors: Braimoh Omoigberai Bashiru , Ilochonwu Nzube Anthony
Published: June 2014

Objective: Dental care is often avoided and misunderstood in pregnancy. The objective of this study was to evaluate the knowledge of dentists on the provision of dental care during pregnancy. Subjects and Methods: A cross-sectional descriptive study among 76 dental practitioners in two Tertiary Health Institutions in Nigeria. The study participants were approached at their duty posts and informed consent was obtained before administering the questionnaire. Data were collected using pretested self-administered questionnaire and analyzed using IBM SPSS statistics version 20.0 (New York, United States). Results: Forty-seven (63.5%) of the participants were registrars, 48 (64.9%) were more than 35 years, and 40 (54.1%) had practiced for more than 5 years. Majority, 61 (82.4%) of the participants were willing to provide dental treatment during pregnancy. Registrars, 39 (64%) were significantly (P = 0.03) more likely to provide dental care during pregnancy than house officers. While 44 (59.5%) of dentists knew the best time to take dental radiograph was the second trimester of pregnancy, 48 (64.9%) knew dental radiographs could be taken in any trimester of pregnancy. Dentists who knew it was safe to use composite and amalgam during pregnancy and perform root canal treatment in the first trimester of pregnancy were 56 (75.6%), 59 (79.5%) and 13 (17.6%), respectively. Conclusion: Though the knowledge of the dentists on dental care during pregnancy was good, this need to be improved upon. Therefore, there is a need to develop guidelines and train dentists on dental care during pregnancy.
Oeler′s type III dens invaginatus: A case report with 1-year follow-up
Authors: George Liza , Mohan Ajit G. , Mathew Justin
Published: June 2014

Dens invaginatus is a rare anomaly that occurs due to deepening of enamel organ into the root, either fully or partially during tooth development. The purpose of this paper is to present a case of Oehler′s type III dens invaginatus on a maxillary left lateral incisor with a large periapical lesion. Combined endodontic therapy and surgery showed good healing when the patient was evaluated clinically and radiographically after 1-year. This case report highlights the importance of proper debridement of the main canal of a case of dens invaginatus because of its complex anatomy.
A Sharp Constant for the Bergman Projection
Authors: Marković Marijan
Published: June 2014

For the Bergman projection operator P we prove that

Here λ stands for the hyperbolic metric in the unit ball B of Cn, and B1 denotes the Besov space with an adequate semi-norm. We also consider a generalization of this result. This generalizes some recent results due to Perälä.