bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Pre-Compressive Strain on Work-Hardening Behavior upon Two-Step Loading in a Magnesium Alloy Sheet
Authors: Hama Takayuki , Tanaka Yuhki , Uratani Masato , Tanaka Tsutomu , Fujimoto Hitoshi , Takuda Hirohiko
Published: March 2015

In the present study, deformation behavior upon two-step loading in a rolled AZ31 Mg alloy sheet was investigated. The experimental procedure was as follows: (1) a sheet was subjected to in-plane compression, (2) small samples were cut from the compressed sheet along various directions, and (3) uniaxial tension was imparted to small samples. The angle between the first and second loading directions was set to either 0, 30, 60, or 90°. During the second loading, a strong in-plane anisotropy occurred in the stress-strain curve: a sigmoidal curve occurred during the second loading for the angles of 0 and 30°, while it did not arise for the angles of 60 and 90°. From microstructural observations, it was presumed that the aforementioned results could be explained in terms of the activity of detwinning.
Identification of Plasticity Model Parameters of the Heat-Affected Zone in Resistance Spot Welded Martensitic Boron Steel
Authors: Eller Tom , Greve Lars , Andres Michael , Medricky Miloslav , Meinders Timo , van den Boogaard Ton
Published: March 2015

A material model is developed that predicts the plastic behaviour of fully hardened 22MnB5 base material and the heat-affected zone (HAZ) material found around its corresponding resistance spot welds (RSWs). Main focus will be on an accurate representation of strain fields up to high strains, which is required for subsequent calibration of the fracture behaviour of both base material and HAZ. The plastic behaviour of the base material is calibrated using standard tensile tests and notched tensile tests and an inverse FEM optimization algorithm. The plastic behaviour of the HAZ material is characterized using a specially designed tensile specimen with a HAZ in the gage section. The exact location of the HAZ relative to the centre of the RSW is determined using microhardness measurements, which are also used for mapping of the material properties into an FE-model of the specimen. With the parameters of the base material known, and by assuming a linear relation between the hardness and the plasticity model parameters of base material and HAZ, the unknown HAZ parameters are determined using inverse FEM optimization. A coupon specimen with HAZ is used to validate the model at hand.
A Constitutive Model for the Simulation of the Deformation Behavior of TWIP Steels
Authors: Haufe André , Erhart Andrea , Butz Alexander
Published: March 2015

Due to their high strength (tensile strength > 1GPa) in combination with an extreme ductility (failure strain 30-50%) TWinning Induced Plasticity–steels (TWIP-steels) can be considered as promising materials for the production of lightweight automotive components. The industrial application of TWIP-steels requires a fundamental experimental validation of the mechanical behavior as basis for an user-friendly but at the same time accurate constitutive framework and its implementation into commercial Finite Element codes. Related investigations and implementations in order to allow for the simulation of TWIP-steel forming processes are currently conducted within the research project “TWIP4EU”, executed as a cooperation of Fraunhofer - Institut für Werkstoffmechanik IWM in Freiburg (Germany), Salzgitter Mannesmann Forschung GmbH (Germany), Swerea KIMAB (Sweden), Faurecia Autositze GmbH (Germany / France), DYNAmore GmbH (Germany) and ESI GmbH Engineering System (Germany / France).The monotonic one-dimensional hardening behavior of TWIP-steels as a function of the twin volume fraction and dislocation density has been described by Bouaziz et al. (2008), Bouaziz et al. (2011). This model has been proven to be adequate for the description of the flow behavior of TWIP-steels and serves as basis for the constitutive model, presented here. This Bouaziz-model has been extended to a three-dimensional elasto-plastic formulation, including the influence of different loading conditions, anisotropy and kinematic hardening. The present paper deals with the implementation for solids and shells in the commercial Finite Element Code LS-DYNA®and appropriate validation simulations will be presented.
Design of Numerical Simulations of Linear Friction Welding Processes: Issues and Difficulties
Authors: Ducato Antonino , Campanella Davide , Buffa Gianluca , Fratini Livan
Published: March 2015

In this paper, a critical analysis of the technical difficulties and numerical issues in running simulations of linear friction welding processes is carried out. The focus of the paper is the comparison of different modeling strategies of a numerical analysis for the LFW process of Ti-6Al-4V titanium alloy, for which the thermal aspect strongly influences the mechanical behavior due to the phase transformation, taking place over a definite range of temperature. A 3D simulation campaign, conducted using the FEA code DEFORMTM, was considered in order to show advantages and disadvantages of each approach, including the most critic limitations and complexity in a correct simulation design using two deformable objects.
Solid State Recycling of Aluminium Sheet Scrap by Means of Spark Plasma Sintering
Authors: Paraskevas Dimos , Vanmeensel Kim , Vleugels Jef , Dewulf Wim , Duflou Joost R.
Published: March 2015

Various solid state or ‘meltless’ recycling techniques have recently been developed for light metal scrap in form of chips. Main objective of all approaches is to bypass the need for remelting in order to reduce the overall required energy, and to avoid the material losses that occur during this step. Within this paper, the use of Spark Plasma Sintering (SPS) is proposed as a novel solid state recycling/welding technique for sheet metal scrap. Aluminium 5182 alloy scrap, derived from sheet metal, was successfully consolidated into a fully dense billet via SPS. The use of pulsed electric current heating, in temperatures well below the alloy melting point, combined with mechanical pressure, enchased the densification process resulting into a void-less material. The recycled SPS sample was fully densified and microstructural investigation has been performed in order to confirm effective oxide film breakage. The results illustrate the effectiveness of SPS in aluminium scrap consolidation, also in form of sheet scrap, providing additional means in solid state recycling. The involved mechanisms that contribute to oxide film fracture and scrap consolidation in SPS are being discussed.Keywords: Aluminium, recycling, spark plasma sintering (SPS)
New Diagnostic Techniques for an Automated Hemming Validation of Hang-On Parts
Authors: Kaiser Christoph , Zubeil Martin , Roll Karl , Volk Wolfram
Published: March 2015

Due to the increasingly shorter development times in the automotive industry the aspect of a continuous virtual product validation is getting more important. For example, in the field of the body in white construction the metal forming-specific process steps in the press shop and the hemming processes in the body shop are designed with the aid of finite element simulations. Even though the computing speeds of the latest finite element solvers are increasing constantly, there is still a huge effort in time to do the pre-and post-processing of a hemming simulation. In order to improve the response time of the hang-on-parts’ manufacturing process verification, a metamodel-based part analysis is aspired. Based on a categorization of the part outline, which has to be analysed, a validation of the hemming process is carried out by using mathematical metamodels in terms of predicting failure probability and production feasibility. By splitting up the part outline into individual segments a fast analysis can be achieved. Here, an automated process is evaluating each segment individually with a special diagnostic technique. The system delivers output results, such as plastic strain values, the tendency of wrinkling, flange length, roll in, etc. Especially in an early development phase, this procedure is advantageous to compare and evaluate different hemming concept alternatives on an efficient way. The high variety of hang-on-parts, which have to be validated, requires that the simulation outlay has to be as small as possible. With this new diagnostic technique an automated hemming validation of hang-on-parts can be executed without doing a finite-element-simulation. So, there is no simulation model which has to be set up, calculated and evaluated. This helps to reduce the time effort and the amount of simulation loops for validating a hemming process. Furthermore, the degree of the part maturity is increased in an early development phase very efficiently.
Minimization of Energy Consumptions by Means of an Intelligent Production Scheduling
Authors: Mariano Emilia , Nucci Francesco , del Prete Antonio , Grieco Antonio
Published: March 2015

Nowadays achieving overall sustainability in industrial activities is the natural consequence of diminishing non-renewable resources and stricter regulations related to environment and occupational safety/health.In industrial sector, CO2 emissions derive both from direct and indirect emissions. The second type is due to the use of electricity and currently represents more than thirty percent of global amount. For this reason energy consumption reduction is critical aspect in several industrial environments. Power consumption reduction is possible by modifying manufacturing conditions, utilizing alternative technologies and increasing resource utilization rate.The current market demand is characterized by request of small lots with different characteristics, which requires a complex management of the manufacturing production flow.Production planning and scheduling models, arising in flexible manufacturing environments, allows to combine several aspects such as: technological questions (e.g.: minimize manufacturing times and costs) economic criteria (e.g.: maximize production rate) and environmental prospective (e.g.: emissions reduction). A good manufacturing scheduling allows to saturate the system, avoiding bottlenecks, by means of the adaptation of the plant productivity to the request one.In this paper, authors describe an optimization framework focused on the minimization of energy and production costs by means of an intelligent production scheduling. In order to assess the performances, different real case production scenarios, in which the manufacturing activity is mainly based on machining operations, have been analyzed. In this work, several technologies, with various capabilities, have been taken into account in order to perform production activities. In addition, the scheduling has the possibility of using production technologies with low environmental impact and lower productivity, where the increase of the activity duration does not deteriorate the system performance. In this way several production schedules are feasible and the main scheduling aim focuses in obtaining the required productivity to fulfill demand and minimize energy consumption.
Fracture Prediction in Sheet Metal Stamping Based on a Modified Ductile Fracture Criterion
Authors: Zeng Rong , Huang Liang , Li Jian Jun
Published: March 2015

Sheet metal stamping is an important manufacturing process because of its high production rate and low cost, so the fracture prediction of stamping parts has become important issues. Recent experimental studies have shown that the quality of stamping parts can be increased by using ductile fracture criteria. This paper proposed a modified ductile fracture criterion based on the macroscopic and microscopic continuum damage mechanics (CDM). Three-dimensional (3D) explicit finite element analysis (FEA) are performed to predict the fracture behaviors of sheet metal stamping process. An approach to determine the material constants of modified ductile fracture criterion is presented with the help of uniaxial tensile tests and compressive tests. The results show that the modified ductile fracture criterion enables precise cup depth and fracture location of sheet metal stamping under nonlinear paths. Compared with typical ductile fracture criteria, the results predicted with modified ductile fracture criterion correlate the best with the experimental data.
Lightweight Design in Architecture – Forming of Stainless Steel Composites for Modern Facades
Authors: Tulke Marc , Watzke Jennifer , Brosius Alexander , Schomäcker Michael
Published: March 2015

This paper shows the characterisation of a new composite material for architectural applications. The stainless steel and polyethylene laminate offers new possibilities in forming optically pleasing facade shapes. A selection of possible structures is presented as a result of extensive simulation studies. The presented structures are generated with a new pneumo-mechanical stretch forming process.
On the Friction Effect on the Characteristics of Hydroformed Tube in a Square Section Die: Analytical, Numerical and Experimental Approaches
Authors: Abdelkefi Abir , Boudeau Nathalie , Malecot Pierrick , Michel Gérard , Guermazi Noamen
Published: March 2015

A focus on the effect of friction condition on tube hydroforming during corner filling in a square section die is proposed. Three approaches have been developed: an analytical model from the literature has been programmed, finite element simulations have been conducted and experiments have been carried out. Effect of friction coefficient on the thickness distribution in the square section of the hydroformed tube is studied. Critical thinning is found to take place in the transition zone between the straight wall and the corner radius and this minimal thickness seems to be the more appropriate parameter for the evaluation of the friction coefficient.
Study of Earing Defect during Deep Drawing Process with Finite Element Simulation
Authors: Patel Ravikant , Dave Harshit , Raval Harit
Published: March 2015

Deep drawing is one of widely used sheet metal working process in industries to produce cup shaped components at a very high rate. In deep drawing process, a sheet metal blank form cylindrical components by process in which central portion of sheet is pressed into die opening to draw the metal into desired shape without folding the corners. Earing is one of the major defects observed during deep drawing process due to anisotropic nature of sheet metal. Earing is defined as formation of waviness on uppermost portion of deep drawn cup. Knowledge about ear formation in deep drawing process allows a prior modification of process which can result in defect free final product with financial saving and time. The initial blank shape used in present study is circular in nature.The objective of present study aims to produce parts which are earing defect free. Earing can be reduced by modifying the initial blank shape such as use of non circular blank as in present study. Efforts have been made to study the earing problem in deep drawing of cylindrical cups by finite element modeling software HYPERWORK-12 and Incremental RADIOSS as solver. The blank material selected for study is EN10130FeP06 mild steel sheet of 1mm thickness as it has wide application in fabricating automobile parts. Mechanical parameters of mild steel are incorporated in finite element simulation of deep drawing process. Significant earing was observed at rolling and transverse direction on deformed cup form circular blank. Modification of initial blank is done to reduce the earing defect. The results show significant reduction of % earing height and drawing load as well as improvement in maximum thickness variations.
Design and Simulation of a Bending Actuator Based on Super-Aligned Carbon Nanotube/Polymer Composites
Authors: Zhang Wei , Weng Ming Cen , Chen Lu Zhuo
Published: March 2015

Super-aligned carbon nanotube films are carbon nanotube macrostructures which have excellent orientations. The bending actuator based on super-aligned carbon nanotube/polymer composites can make a significant controllable bending deformation under a very low DC voltage (< 700 V/m). In this paper, we explored how to make the thermal induced actuator reach maximal deformation. By theoretical modeling and simulation through Mathematica software, the relationship between free-end displacement of the actuator and actuator length, thickness (or thickness ratio) of two layers, difference of coefficient of thermal expansion between two layers, temperature variation and other parameters were studied. Simulation results showed that the deformation is greatly influenced by the thickness ratio of the two layers of the actuator. The deformation displacement reaches a maximum value with a specified thickness ratio. This study may provide valuable theoretical references for the experimental design of carbon nanotube composite actuators.
Effect of the Difference in Dielectric Constant of the Phases on Dielectric Property of the Composites
Authors: Zhou Hao , Zhang Qing Meng , Tang Qun , Cui Hang , Xu Yao Hua , Du Jun
Published: March 2015

The composites have a great use in practical application. In common, the phases in composite have different relative dielectric constant and in order to reveal how the phases with different permittivity affect the composite’s dielectric properties, the experiments were carried out using inorganic and organic composite with different dielectric constant phases to make that clear. The barium niobate-based SiO2system glass–ceramic and fillers-epoxy resin composites were chosen, and the dielectric properties were tested to compare the difference of those composites. The results show that the existence of high dielectric constant phases in composites can improve the permittivity of composites and make the composites present ferroelectric properties, while the dielectric loss can also increased, and the difference in dielectric constant of the phases can decrease the dielectric breakdown strength.
Morphology of Nanotube Governs the Photoelectric Performance
Authors: Shi Xiao Guo , Tian Ang , Yang He , Liu Chuang Wei , Xue Xiang Xin
Published: March 2015

Highly ordered TiO2nanotube array hasbeen widely used as the dye-sensitized solar cells’ (DSSCs) light anode material forits abilities of inhibiting electronic recombination at the interface and improving the beam transmission of the carrier. The morphology and structure of the nanotube would influence the efficiency of the cell. In thisstudy, TiO2nanotubes (caliber ranging from 50 to 150nm, length ranging from 0.9 to 4μm) were prepared by a two-step anodization method and the morphology of nanotubes was regulated bythe parameters such as oxidation voltage and oxidation time. The absorbing capacities of nanotubes were measured by the dye adsorption test and the corresponding photoelectric conversion efficienciesweremeasured too. The results indicated that the conversion efficiency was related to the specific surface area and length of the nanotube. The length of nanotube would increase with theoxidation time within acertain limit.Then thedissolution on the top of TNT would reduce nanotubes’ length and lead to the decrease of the specific area, eventuallyimpairedthe photoelectric conversion.
Research on Fatigue Failure of Steel E4330 for Fluid Cylinder
Authors: Huang Ben Sheng , Lu Jie
Published: March 2015

Fluid cylinder as an important fracturing equipment with stable and reliable performance is commonly applied in oil and gas fields, but it fractures frequently and its working life is generally low, which has seriously affected the fracturing process efficiency. In this paper, we used the stereo microscope, scanning electron microscope (SEM), direct reading spectrometer, metallurgical microscope and bending fatigue testing machine to study the fatigue failure mechanism of steel E4330 for fluid cylinder. The fracture analysis, hardness test, metallographic observation, bending fatigue test and pre-corrosion fatigue test were carried out. The result shows that the main cracking form of the fluid cylinder is fatigue cracking, the cleavage crack initiated near the intersection line and extended friable due to the corrosion and impact wear effects from the fracturing fluid and the high stress of the fluid cylinder; the fluid cylinder material E4330 contains a variety of alloy elements, and its organization is the uniform sorbite which can meet the working requirements. It has been observed that the fatigue limit of the material is 607MPa, and at a higher stress, the fatigue life would be nearly halved in the corrosive environment. As the fatigue life would greatly reduce due to the corrosion effects from the fracturing fluid, we should control the working stress and make measures for anti-corrosion.
Preparation and Electrochemical Properties Research of Vanadium-Sol Modified LiFePO4 Cathode Material for Lithium Ion Batteries
Authors: Ye Li Qiang , Fu Dong Ju , Chen Jian Jun , Ma Qing , Zhang Wei Li , Tan Man Lin , Li Dong Shuang
Published: March 2015

Vanadium-sol modified LiFePO4 material was prepared by 300 °C calcination in a tube furnace. The modified LiFePO4 material was characterized by X-ray diffraction, field emission scanning electron microscopy, energy disperse spectroscopy and electrochemical impedance spectroscopy. The results indicated that vanadium-sol modified LiFePO4 had higher first cycling efficiency, lower impedance and polarization, and better electrochemical properties at high charge/discharge rates.
Study on the Gold Leaching Process by Potassium Ferricyanide
Authors: Tang Ping , Liu Jing , Song Min Wei , Yu Hai Ping , Zhang Xu
Published: March 2015

The traditional gold leaching method is cyanidation, which carries serious security and environmental problems. More and more attention is paid to the research on non-cyanide process. A high-arsenic-and-sulphur refractory gold concentrate in Sichuan was taken as the object of study. After the roasting-oxidation pretreatment of the sample, potassium ferricyanide was adopted to carry on the process experiment on gold-leaching. The leaching results as well as correlative process conditions were both investigated. The results showed that good leaching effects could be achieved by potassium ferricyanide. When the amount of potassium ferricyanide was 60g/L, the concentration of NaOH 0.2mol/L, the liquid-solid ratio 6:1 and the leaching process at room temperature lasted for 20h, the gold leaching rate reached 88.1%. If the leaching aid CaO2 is added simultaneously, it can contribute to the gold leaching. When the amount of CaO2 was 3g/L, the gold leaching rate increased to more than 94%, the amount of potassium ferricyanide decreased to 50g/L and the leaching time reduced to 14h.
Research on Corrosion Rate of Sucker Rod Steel 20Ni2Mo in Wet H2S Environment
Authors: Qu Wen Tao , Liu Si Ying , Xu Zhang Shi
Published: March 2015

Among the factors to cause the corrosion in oil and gas fields, H2S is the most common and harmful corrosive medium. During oil field exploitation, enhancing the ability of the sucker rods to resist corrosion is the key measure of prolonging the service life of sucker rods and guarantee of safe operation of petroleum equipment. This paper focuses on the corrosion of sucker rod steel 20Ni2Mo in different concentrations or temperatures of H2S. The appearance of corrosive surface scanned by scanning electron microscope was analyzed and theoretic basis for anti-corrosion and material-selecting of sucker rods used in the oil fields was provided. The result shows that the concentration and temperature of H2S have interaction on the corrosion of 20Ni2Mo, i.e., with the increase of concentration under same temperature or with the rise of temperature under same concentration, the corrosion rate of 20Ni2Mo accelerates.
Process of Salicylic Acid-Type Composite for Rare Earth Ions
Authors: Yao Yu Yu , Liu Jing , Wu Yong Qiang , Zheng Min Min , Tang Chun Mei
Published: March 2015

The chelation adsorption behavior of a salicylic acid-type composite ASA-PGMA/SiO2for rare earth ions of the rare earth ore mud leaching solution in Mianning was studied in the present work. The effect of the reaction temperature and medium pH on adsorption properties of the ASA-PGMA/SiO2particle was examined. The concentrations of REEs were determined by ICP-MS. The results showed that the ASA-PGMA/SiO2possessed strong chelation adsorption ability for rare earth ions. The reaction temperature was 50°C, the adsorption properties of the composite were the best and the adsorption rate of rare earth ions reached above 90%. In the pH range where the hydrolysis of rare earth ions was inhibited, an increase in the pH value of the medium strengthened the chelation adsorption ability of the ASA-PGMA/SiO2particle for rare earth ions. The rare earth ions desorption from the ASA-PGMA/SiO2particle is effective when using 0.2mol/L of hydrochloric acid solution as the eluent.
Research and Preparation of High Quality Polysilicon Ingots and Multicrystalline Silicon (mc-Si) Cells
Authors: Luo Da Wei , Li Jun Feng , Long Jian Ping
Published: March 2015

Directional solidification is a main method of mc-Si production for solar cells. The main impurities in MS-Si are oxygen and carbon. In this paper, an improved furnace was designed to reduce the carbon and oxygen impurity in MS-Si at unidirectional solidification process. Simulation results showed that the flow pattern of impurity gas at the top of the silicon melt significantly improved under the small cover conditions and the impurity gas eddy currents was also avoided. Experimental results show that the carbon and oxygen content inside the ingot were both significantly reduced when the eddy currents inside the crucible was suppressed and the average minority carrier’s lifetime of silicon block was significantly increased under the conditions of small cover plate. Meantime, the average cell efficiency of ingot was more than 17% under small cover condition which is significantly higher than that of the ordinary ingot.
Preparation of New Multi-Component Nanometer Manganese Dioxide/Carbon for Air Electrode
Authors: Lu Qi , Long Jian Ping , Li Shuang Jie
Published: March 2015

Lithium air batteries have aroused a considerable concern all over the world owing to their outstanding performances. Especially, catalysts of the air electrode, as one of the most core components of lithium air batteries, have been most extensively studied in recent years. In this paper the nanometer manganese dioxide catalysts and their compounds with Super P, TNRGO and OMC were prepared successfully via hydrothermal synthetic method. Characterized by XRD, SEM and BET, most of them have regular shape, perfect dispersion and high specific surface area, especially SBETof MnO2/TNRGO/OMC of the three-component catalysts was up to 126.70m2/g. The air electrodes with nanoMn02/carbons catalysts have lower resistance, and better reversibility.
Effects of Current Density on the Properties of Microarc Oxidation Coatings Formed on Aluminum Alloy in Silicate-Na2MoO4 Electrolyte
Authors: Wang Ping , Wu Ting , Guo Xiao Yang , Peng Ya
Published: March 2015

Microarc oxidation (MAO) coatings on ZL108 aluminum alloy were prepared in the silicate-Na2MoO4 electrolytes with different current density. The MAO process was studied by measuring the voltage as a function of time. The microstructure, compositions, distribution of element and corrosion resistance of the MAO coatings were investigated by SEM, XRD, EDS, XPS and polarization curve, respectively. With the increasing of current density, the final voltage in the microarc discharge process increased. The results shown that the MAO coatings were mainly composed of mullite, γ-Al2O3, Si, little MoO2 and MoO3. The micropore size, thickness, compositions, distribution of element of the MAO coatings depended on the current density and the amount of MoO2 and MoO3. The corrosion resistance improved as the porosity of the MAO coatings decreasing.
Life Cycle Analysis on Carbon Emission Reduction and Energy Saving by Using Slag as Alternative Materials in Cement Production
Authors: Li Yao , Liu Yu , Shi Fei Fei , Wang Zhi Hong , Gong Xian Zheng
Published: March 2015

The carbon emission and energy consumption of using slag as a secondary raw material in cement production was quantified and analyzed in this study. Moreover, the carbon emission reduction and energy saving potential of slag-based cement (SBC) production were identified based on the comparative analysis between SBC and traditional Portland cement (TPC). The results showed that the carbon emission of SBC is about 6.73%, which was lower than that of TPC. Compared with TPC, the energy consumption of SBC is slightly increased by 2.05%. In addition, it was found that the combustion of coal and the power generation were the main sources for carbon emission in the life cycle of slag utilization, which account for 83.39% and 10.16% of the total carbon emission. Therefore, reducing the consumption of energy and increasing the recovery rate of waste heat in cement production were the most effective methods to improve the environmental performance of SBC. In addition, the improvement potential analysis was carried out for SBC. The results indicated that if the recovery rate of waste heat could reach to that of the international advanced level (15.6%), the carbon emission and energy consumption of SBC would be reduced by about 2.20% and 5.71%, respectively. If the proportion of renewable energy utilizationin power generation increased to that of the average international level, the carbon emission and energy consumption of SBC would be declined by 5.26% and 9.35% respectively.
Removal of Metal Ions from Aqueous Solutions by Microcapsules Prepared by 8-Hydroxy-Quinoline with Polystyrene
Authors: Chen Wei Xing , Gao Xiao Fang , Ma Ai Jie
Published: March 2015

The removal of Fe3+, Cu2+,Cd2+,Cr3+and Zn2+ions from aqueous solution was studied by sorption onto polystyrene microcapsules containing 8-hydroxy-quinoline as extraction reagent. The micro-capsules containing 8-hydroxy-quinoline were prepared by solvent evaporation method with O/W emulsion and characterized by using optical microscope, Fourier Transform Infrared Spectroscopy (FT-IR). The uptake to Fe3+, Cu2+,Cd2+,Cr3+and Zn2+ions into the microcapsules was studied at deferent conditions. It showed that with the increasing dosage of microcapsules, the removal of metal ions increased too. The longer is standing time, the more is the increasing of adsorption capacity. The sorption of metal ions decreases with the initial pH of the solution increasing, and the sorption of microcapsule for metal ions is lower at 50°C. The sorption of Cr3+, Cu2+and Zn2+ions is highest at 45°C, and that of Fe3+, Cd2+is at 40°C. The results showed that the microcapsules could absorb Cr3+ions better than other metal ions.
Multi-Scale Polyimide/Carbon Fibers Hybrid Filters for Hot Gas Filtration
Authors: Wang Qian Nan , Bai Yu Ying , Xie Jian Fei , Qiu Yi Ping , Jiang Qiu Ran
Published: March 2015

Increasing air pollution caused mainly by exhaust emission has become a serious concern for public health. In order to efficiently control the exhaust emission from the origin, hot gas filtration is required in many industries, such as thermal power regeneration, metal refining/recycling, and biomass/coal gasification. This study aimed to develop a hybrid filter composed with ultrafine fibrous polyimide (PI) filtration layers and carbon woven fabric supporting layers for hot gas filtration. Uniform PI ultrafine fibers around 200 nm with small pores about 2.2 μm were electrospun on carbon fabrics supporting layers to serve as the filtration layer. During filtration test, NaCl aerosols (0.3 mm), which mimicked PM 2.5 particles were accumulated on the top of filtration layer and formed dust cake, but limited aerosols were observed on the carbon fabric supporting layers. It was proved that PI fiber mats played the key role in filtration. The filtration efficiency could be maintained above 95% after 9 min and reached 99.4 %. This research proved that the multi-scale polyimide/carbon fibers hybrid filters possessed the potential to serve as filtration media in bag filters for hot gas filtration.
Potentials for Denox in Chinese Cement Industry with the Life Cycle Assessment Method
Authors: Li Chen , Cui Su Ping , Meng Xian Ce , Peng Zhen Guo , Gong Xian Zheng , Liu Yu
Published: March 2015

To explore NOx mitigation strategies in Chinese cement industry systematically, a material flow analysis was developed. The realistic output of cement production in China were identified and quantified. The inventory data of Chinese cement production were selected without denitration technology applications at that time. Then the life cycle impact assessment (LCIA) results were calculated with the principal of ISO 14040 and ISO 14044 of Life Cycle Assessment. The impact categories of global warming potential (GWP), acidification potential (AP), eutrophication potential (EP), photochemical oxidant formation potential (POCP), and human toxicity potential (HTP) were used to calculate environmental impact. The results showed that the NOx emission was the major environmental damages and the following was CO2 emission. This argument disagreed with the view that CO2 emission was the major contributor of environmental load. The reason is that the NOx emission is far over the international level due to few denitration technology applications. In the assumption of selective non-catalytic reduction (SNCR) technology applications, there is still large emission mitigation potential according to the target scenario analysis. The application of selective catalytic reduction (SCR) technology with higher deNOx efficiency and the roadmap of deNOx of Chinese cement industry were also discussed. The SNCR technology with the auxiliary of SCR development over the coming decades will be decisive for the roadmaps of Chinese cement industry to reach deeper NOx emission cuts.
Influence of Process Conditions on the Structure and Hydraulic Activity of Air-Cooling Blast Furnace Slag
Authors: Wang Hui , Cui Su Ping , Wang Ya Li
Published: March 2015

Using the industrial limestone, fly ash and pure chemical reagents as raw materials, the blast furnace slag was prepared by the fast air-cooled method. Using orthogonal experiment method, the influence of process conditions such as heating rate, heat preservation time of the blast furnace slag in hearth, discharge temperature of slag and cooling speed on the glass content and hydraulic activity of blast furnace slag were studied, the main influence factors and the optimal process conditions of blast furnace slag were determined. The results showed that the discharge temperature of slag was the key factor influencing on the glass content of granulated blast furnace slag. The impact degree of all process conditions on the glass content of granulated blast furnace slag accord with the following sequence: discharge temperature of slag > heat preservation time > heating rate > cooling rate. And heat preservation time and cooling rate were the key factors influencing 28 days activity index of blast furnace slag, the impact sequence of all process conditions on the 28 days activity index of granulated blast furnace slag was as follows: heat preservation time > cooling rate > discharge temperature of slag > heating rate. This study also optimized the process conditions of granulated blast furnace slag for different indicators.
Life Cycle Inventory of Gangue as Alternative Raw Materials
Authors: Peng Zhen Guo , Gong Xian Zheng , Liu Yu , Li Chen , Liu Xiao
Published: March 2015

With the development of science and technology and industry level, solid wastes are fully utilized. Among which gangue is the solid waste generated in the process of coal mining, its comprehensive utilization rate is more than 60%. Environmental pollution in the process of coal mining is one of the typical environmental problems confronted in China. In this paper, the life cycle inventory (LCI) of gangue was acquired by the method of life cycle assessment and further environmental impact assessment was achieved as well. The results showed that environmental impacts based on allocation of calorific value were greater than that of economic value, and it’s about 3.68 times the impacts assigned by economic value. Therefore allocation of economic value was better.
Utilization of Municipal Sludge in the Calcination of Cement Clinker
Authors: Zhao Qi Gang , Nie Zuo Ren , Liu Hong , Cui Su Ping , Wang Ya Li
Published: March 2015

Using the sludge of sewage treatment plant to calcine cement clinker is a new method and is confirmed on the international to utilize city sludge recycling and harmlessly. In this work the test of the raw material burnability, cement clinker mineral composition and petrographic analysis were used to study microscopic characteristics of clinker, to analysis of the effect of sludge performance of cement clinker calcination. It was found that when sludge were as a raw material for calcining cement clinker, best city sludge content was around 15% ~ 20%. With an improvement of lime saturation coefficient, the burnability of raw material declined. The mineral composition of sludge clinker was the same as that of the conventional Portland clinker, while mineral structure and morphology of the sludge clinker were better.
Effect of pH and Concentration of Ca2+ on Spherical Calcium Carbonate Crystallization by Continuous CO2 Gas Bubbling into Phosphogypsum Leaching Solution
Authors: Liang Ya Qing , Sun Hong Juan , Peng Tong Jiang
Published: March 2015

Spherical calcium carbonate (CaCO3) is a potential component in many industrial fields such as high-grade papermaking, high-grade painting, environment, and pesticide. This paper describes a novel approach to synthesize spherical calcium carbonate (CaCO3) particles via passing CO2 bubbles into phosphogypsum salt leaching solution (CaSO4) in the presence of ammonia (NH3) at different temperatures. The influence of the initial solution pH and concentration of calcium ions on the polymorph and morphology of CaCO3 was studied. The physical characteristics of the precipitate were evaluated using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that compared with different calcium sources the phase and morphology of CaCO3 synthesized by phosphogysum leaching solution had some regularity. The grain size of spherical CaCO3 became bigger, surface became smoother, and particle dispersion became better with the increase of calcium ion concentration. The content of vaterite increased and particle grain size changed a little with the increase of pH. The research results had important environmental significance for phosphogysum resource utilization and CO2 fixation.
Theoretical Calculation and Experimental Study on the Forming Heat of Cement Clinker Made from Steel Slag
Authors: Wang Ya Li , Cui Su Ping , Tian Gui Ping , Lan Ming Zhang , Wang Zhi Hong
Published: March 2015

When steel slag, a by-product of steel making in impurity catching process, is added, the forming process of cement clinker and the major reactions in that process are changed. Since there are dramatic differences between the chemical components and mineral compositions of steel slag and that of natural cement raw materials, the empirical equation for the calculating forming heats of cement clinker made of limestone and clay is no longer applied for those made of steel slag. In this paper, the empirical equation for forming heat calculation of steel slag added cement clinker was promoted, and testified by acid dissolution experiments. Results showed that the change of raw materials had great influence on the forming heat of cement clinker. When the traditional raw materials were replaced with steel slag, the forming heat of cement clinker reduced. Calculating the forming heat by our revised empirical equation can help reduce errors and bring great convenience for the calculation and evaluation of heat efficiency. This research provides theoretical underpinning for the study and calculation of forming heat of steel slag added cement clinker.
Visible-Light Photocatalytic Performance of N/RH/TiO2 Complex Materials
Authors: Feng Qing G. , Qin Si Y. , Wang Ting , Weng Xiao F. , Song Bao L. , Wang Dong B.
Published: March 2015

The TiO2complex samples were produced through sol-gel method, using Ti (OC4H9)4, rice husk (RH) and methenamine as the reactants. Some property analyses were conducted, including X-ray diffraction (XRD), Brunauer-Emmet-Teller (BET), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and photocatalytic experiments in the condition of visible-light. The results showed that the size of crystal was limited with the addition of RH in the complex of N/RH/TiO2samples. The particles of TiO2were dispersed on the surface of rice husk ash, the skeleton of RH after burning. It can inhibit the phenomenon of agglomerate. The ability of both adsorption and photocatalytie activity of complex samples increased as the surface area increased. Doping N into RH/TiO2samples can decrease the forming time, inhibit the transformation of crystal from anatase to rutile to some extent, improve the bond of Ti-O-Si to form and make the absorption spectrum move to the red light part. The complex samples exhibited a certain photocatalytic activity under the visible light region. The reaction rate of visible light photodegradation process arrived 0.0143 min-1, meeting with the first-order reaction kinetics.
Preparation and Heat Transfer/Thermal Storage Properties of High-Temperature Molten Nitrate Salts
Authors: Zhang Hong Tao , Zhao You Jing , Li Jing Li , Shi Li Jie , Wang Min
Published: March 2015

The thermal stability of molten salts, operating temperature range and latent heat of melting for the molten salts at high temperature have been studied in the present investigation. The multi-component molten salts composed of purified potassium nitrate, purified sodium nitrate were prepared by statical mixing method [1]. The stability experiments were carried out at 500 to 600°C, and the experimental result showed that the purified nitrate molten salts performed better high-temperature thermal stability and its optimum operating temperature was increased from 500°C to 550°C. DSC analysis indicated that the purified nitrate molten had a lower melting point and a higher phase change latent heat. The melting point of purified binary nitrate molten salts was sharp decreased to 225.2°C and latent heat of melting for molten salts was also reduced from 78.41J/g to 81.15J/g compared with unpurified nitrate salts. Besides, the change in the concentration of impurities by analyzing in the binary molten salts, and combination of XRD test results can be found that the degree of degradation reduce and improve the thermal efficiency of the storage of binary molten salts by purified sodium nitrate and potassium nitrate.
Structure and Photoelectric Properties of Cu3N Thin Films by Reactive Magnetron Sputtering
Authors: Leng Jin Feng , Chen Li Na , Zhu Xiao Zhe , Sun Zhen He
Published: March 2015

Cu3N thin films can potentially be used for development of optical storage devices and integrate circuit of semiconductor. In this study the Cu3N films were deposited on glass substrate successfully by reactive direct current magnetron sputtering at different N2/(N2+Ar) flow ratio. The results showed that the nitrogen partial pressure affected the preferring orientation of the thin films when the sputtering power and substrate temperature was fixed. With increasing N2/(N2+Ar) flow ratio from 10% to 90%, Cu3N(111) orientation with rich-copper changed to Cu3N(100) orientation with rich nitrogen, the transmittance of the thin films improved gradually, and the corresponding optical band gap (Eg) increased from 1.10 eV to 1.21eV. The resistivity of copper nitrogen films changed from 5.62Ω.cm to 3.00×103Ω.cm at the scope of 10%~90% of N2/(N2+Ar) flow ratio.
Sintering Properties of Apatite-Type Lanthanum Silicate Electrolytes
Authors: Shi Qing Le , Zhang Hua , Li Tian Jing , Yu Fang Li , Hou Hai Jun , Han Peng De
Published: March 2015

The sintering properties of appetite-type lanthanum silicate La10Si6O27prepared by sol-gel process were studied. The precursor powder was sintered by one-step sintering (OSS) process, two-step sintering (TSS) process and spark-plasma sintering (SPS) process. The phase structure, microstructure, relative density, thermal expansion properties, electrochemical properties of the samples were investigated by means of the techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), Archimedes method, dilatometer, and AC impedance spectroscopy. The experimental results show that the samples sintered by SPS process can decrease the sintering temperature, shorten the sintering time, increase the density, and reduce the particle size. The appetite-type lanthanum silicate La10Si6O27 sintered by SPS process shows better sintering properties than of sintered by OSS process and TSS process, which can beneficial to the thermal expansion properties and conductivity.
Fabrication of Silica Monoliths with Hierarchically Porous Structure from Freeze-Drying
Authors: Lu Lu , Wei Yu Lei , Lin Jie , Qian Lei
Published: March 2015

This paper provides a novel route to prepare silica monoliths with hierarchical porous structure via freeze drying. In this method, macroporous silica monoliths were first produced by freeze-drying and calcination. By adjusting the concentration of cetyltrimethylammonium bromide in ethylsilicate, a layer of mesoporous thin film was attached on the macroporous silica monolith. The structural characterization of the hierarchical porous monoliths were studied by field emission scanning electron microscopy, mercury porosimeter and nitrogen adsorption-desorption techniques (BET). It turned out that the pore distribution of the obtained monoliths was ranged from 3.72 nm to 23.21nm and the maximum specific surface area calculated from BET was about 288 m2/g, which indicated the existence of hierarchical structure in the obtained material.
Preparation of Nickel and Manganese Dioxide by Co-Precipitation and its Electrochemical Capacitive Properties
Authors: Li Qian Qian , Fan Run Hua , Bai Yu Jun , Cheng Chuan Bing , Liu Gui Fang , Lu Lu , Xie Pei Tao
Published: March 2015

The precursor nickel and manganese carbonates were synthesized by co-precipitation with sodium carbonate as precipitant, and then nickel and manganese oxides were gained after calcination. The phase and morphology of the synthesized product were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM), and the electrochemical characterization was performed using cyclic voltammetry (CV), galvanostatic charge–discharge tests (GCD) and electrochemical impedance spectroscopy (EIS) in a 6mol/L KOH aqueous solution electrolyte. The result showed that the products were the mixture of nickel and manganese oxides and solid solution. nanoparticles and spherical particles were gained by controlling the molar ratio of nickel and manganese. All of the samples exhibited typical Faradic redox capacitance. The specific capacitance was different with the change of nickel and manganese molar ratio. The specific capacitance (Cs) reached 130F/g at 1A/g when the ratio was 2:1.
Effect of Bi Addition on Microstructures, Properties and Interfacial Intermetallic Compound Growth of Low-Ag Sn-Cu Lead-Free Solder
Authors: Wang Yuan , Zhao Xiu Chen , Liu Ying , Cheng Jing Wei , Li Hong , Xie Xiao Chen
Published: March 2015

The research on a new low-Ag lead-free solder has become a hot spot in the field of electronic packaging. In this work, the effects of Bi addition on microstructure, melting temperature, wettability of low-Ag solder, shear strength of solder joint and the growth of interfacial intermetallic compound (IMC) before and after thermal cycling were investigated. A moderate amount of Bi element resulted in the microstructural refinement and melting temperature reduction of Sn-0.2Ag-0.7Cu solder. Wetting test results showed that a small amount of Bi produced the significant effect on improving the wettability. In addition, it is shown that the thickness of interfacial IMC during thermal cycling decreased first and then increased; the shear strength of solder joint increased with the increase of Bi.