bluuebunny/crossref_metadata_2025 huggingface dataset:
Surfactant Assisted Hydrothermal Synthesis of Nano-Microsphere Titania
Authors: Zhuang Yun Fei , Bian Ya Lan , Zhang Lin Jing
Published: January 2015

Using titanium trichloride (TiCl3) as the precursor, cetyltrimethyl ammonium bromide (CTAB), polyvinyl pyrrolidone (PVP), sodium dodecyl sulfate (SDS) as the surfactants, sodium chloride (NaCl) as the mineralizer, titanium oxides (TiO2) nanomicrospheres were synthesized at 170 °C for 24 h via hydrothermal method. Use x-ray diffraction (XRD) and scanning electron microscopy (SEM) to characterize the crystal structure and morphology of the microspheres. The results show that pure rutile phase TiO2 microspheres can be prepared with the assist of surfactant by hydrothermal treatment. The spheres were composed of radial aligned nanorods. The diameters of the rods were about 40 nm and the lengths were about 500 nm. The diameters of the TiO2 microspheres prepared using CTAB, PVP, SDS as the surfactant were among 1μm~2μm, 5μm~10μm, and 2μm~5μm, respectively.
Arterial Velocity Planning Based on Traffic Light Conditions for Driver Assist Driving System
Authors: Song Wen , Zhang Xin , Tian Yi , Zhang Xin , Song Jian Feng
Published: January 2015

With the development of modern wireless communication technology, the driver assist driving system gets more and more attention from people, because it could receives many real-time information, such as traffic lights information, road information and so on. The arterial velocity planning algorithm based on traffic lights information makes vehicle more economically and efficiently, because it could help driver decrease the acceleration/ deceleration pattern and idling time. This paper creates 3 arterial velocity planning algorithms by analyzing the vehicle driving process, and the acceleration/deceleration parameters and driving time of these three algorithms are optimized. When the vehicle is driving, the arterial velocity planning algorithm gives the dynamic speed advice to the driver through driver assist driving system, ensures that the vehicle will cross the traffic light without coming to a stop. The results show that the fuel consumption savings for vehicles with arterial velocity planning is above 11% on a relatively smooth arterial road.
Reflections on Improving Emission Reduction of Key Pollutants in Jingdezhen
Authors: Huang Jie , Zhou Jing Kun
Published: January 2015

As Ceramics Capital of China, Jingdezhen had very serious air pollution in the past. In recent ten years, through strengthened management and other means, the total discharge of pollutants has been reduced significantly. The article briefly describes the current situation of Jingdezhen City’s emission reduction work, analyzes its challenges in emission reduction and gives several suggestions for improving Jingdezhen City’s emission reduction work, for example, Jingdezhen City shall vigorously promote clean production, reduce production pollution intensity, resolutely eliminate backward technology and capacity, control pollution emissions of new-built projects, realize supervision and control, strengthen leadership, optimize industrial structure, enhance structural emission reduction and so on.
Application of Fuzzy Safety Evaluation Method in Automobile Enterprises
Authors: Wu Lei , Chen Gang , Wu Long , Zhang Wen Juan
Published: January 2015

Fuzzy evaluation method is a comprehensive evaluation method based on fuzzy mathematics. It is widely used because of its characteristics for clear results and strong system, and it can solve the problem of fuzzy and difficult to quantify. This paper using an automobile enterprise as an example introduces the application of fuzzy safety evaluation method.
A Research on Complex Event Processing Technology Based on Smart Logistic System
Authors: Fu Bin Bin , Zhu Jie
Published: January 2015

With IOT technology developing and the cost reducing, Its application in supply chain is a matter of time. Smart logistic system is one of the IOT technology application in supply chain which solve difficult problems, such as acquisition underlying data, information transfer and so on. we need to achieve higher level application and solve more complex problems such as improving inventory management accuracy, reducing supply chain management cost, improving accuracy of supply and demand prediction, supply chain's rapidly react ability,these need to use complex event processing technology. It will introduce how to apply complex event processing technology to supply chain system based on IOT. By this way we can sort out valuable information by processing a large number of simple event.
Synthesis of High Molecular Weight Cationic Polyacrylamide
Authors: Li Tian Xia , Chen Feng
Published: January 2015

Cationic polyacrylamide is a derivative of polyacrylamide, a cationic polymer flocculant which has an excellent effect on sewage treatment. Our existing cationic polyacrylamide are mostly prepared by the Mannich reaction ,which has the shortcomings of more unreacted material, low cationic degree, poor stability, short validity, etc. Therefore, a cationic polyacrylamide has been prepared by aqueous solution.P(DAC-AM) was synthesized by aqueous copolymerization of acrylamide (AM) and DAC using complex initiated system consisted of (NH4)2S2O8,NaHSO3 and V-50. Mass percent of monomer, amount of initiator, content of cation monomer, pH, reaction time et al on the effect of intrinsic viscosity of polymer were discussed. The suitable conditions of synthesis were concluded. Mass concentration of monomers:35%, initiator amount 0.06 %,V-50 amount 0.005%,pH:5.5~6.5,urea concentration 0.1%,EDTA 0.02%,β-dimethylaminopropionitrile concentration 0.03%,reaction time 5~6h,the intrinsic viscosity of product is 13.95dL·g-1.
Multi-Objective Fuzzy Optimization Design of Truck Differential
Authors: An Er Zhong , Wang Yun Chao
Published: January 2015

Multi-objective optimization technology and Fuzzy theory were applied to design truck differential based on consideration on its force condition. The mathematical model for the multi-objective optimization design was set up under the objective of the minimum volume of the differential, maximal strength of planet gear, with the design variable of planet gear teeth number Z1, axle shaft gear teeth number Z2, section modulus ms and working width b. Then, the fuzzy solution of multi-objective optimization were use to solve the model. Practical example of calculation shows that, the fuzzy optimization result is superior to that of regular optimization and traditional design, differential volume deceased by 32.73% and 1.92% respectively. Comparing with nominal design, the load of planet gear increases 17%, but is far below its permissible value, and also reduced by 9.04% than that of regular optimization.
Analysis of Structure Dynamic Characteristics of ATV Frame with Engine
Authors: Ye Fang , Xu Zhong Ming , Zhai Xi Cheng
Published: January 2015

ATV, also known as the all terrain vehicle, and its vibration comfort has become one of the most important service performance. The frame is the skeleton of ATV, the vibration characteristic analysis of the frame elastic hanging engine, has great effect on vehicle safety and vibration comfort. It is using the computer simulation method for dynamic characteristic research of ATV frame with engine, and the experimental modal analysis is competed in this paper. By comparison to the computational modal and experimental modal results of ATV body, it is found the error within 10%, so the finite element model of car body is effective. Then, it’s found that the ATV body’s resonance is caused by vibration frequency synchronization of the excitation of the engine and ATV body, it provides a direction and method for the improvement of the ATV’s whole ride comfort.
Feed-Water Treatment Technology of Supercritical Unit
Authors: Lu Guo Hua , Peng Qiao Ling , Cao Shun An
Published: January 2015

The oxygenated feed-water treatment technology of supercritical unit can effectively decrease the corrosion of water-steam system, and thus the steam-water quality and the operating efficiency are greatly promoted. In view of the mode of feed-water treatment for supercritical unit, the characteristics of oxide film in thermal system under AVT and OT conditions are compared; and then, the principle of oxygenated feed-water treatment technology was elaborated. Besides, the oxygenated conditions, controlling of water quality, advantages, the relation between the formation of oxide scale and oxygen plus are analyzed and discussed. Finally, the paper introduced weak oxiding feed-water treatment technology for supercritical unit, with the principle of low oxygen and high pH value.
Far-Field Near-Infrared Plasmonic Nanofocusing Effects Based on Nano Metal Structure
Authors: Liang Yan , Cao Peng Fei
Published: January 2015

We design a new near-infrared plasmonic nanofocusing lens for far field practical applications by using nanonoble metal structure. The constructively interference of near-infrared cylindrical surface plasmon launched by the subwavelength metallic structure can form a subdiffraction-limited focus, which is modulated by the dielectric grating from the near field to the far field. The principle of designing such a far-field nanofocusing lens is elucidated in details. The numerical simulations demonstrated that nanoscale focal spot with full width of half maximum (0.43λ) can be obtained in far field with depth of focus about 2.86λ. This design method paved the road for utilizing the plasmonic lens in high-density optical storage, nanolithography, superresolution optical microscopic imaging, optical measurement, and sensing.
Preparation and Property of Mn3B7O13Cl Microwave Attenuation Powders
Authors: Liang Dong , Cao Lin , Jia Cheng Chang , Xiong Sang , Shu Xiao Ning , Wang Cong Cong , Gao Peng
Published: January 2015

Mn3B7O13Cl nanopowders were prepared by sol-gel process. X-ray diffraction (XRD) and Transmission electron microscope (TEM) were utilized to characterize the structure, shape, size of the obtained products. Mn3B7O13Cl powder was sintered into a ceramic disk having a diameter of 20mm by Spark Plasma Sintering (SPS). The formation of Mn3B7O13Cl nanoparticles and the dielectric properties of Mn3B7O13Cl were discussed. The results show that Mn3B7O13Cl nanopowders which was obtained after xerogel roasted at 550°C are uniform. The size of the average particle is about 50nm. Mn3B7O13Cl ceramic disk has a low dielectric constant and high dielectric loss. It is believed that there is a good application prospect in the field of microwave attenuation.
Synthesis and Surface Engineering of La1-xSrxMO3 Nanoparticles for Biomedical Applications
Authors: Cheng Wen Zheng , Zhang Wu , Liu Hong Ling , Li Xue Mei , Liu Xiao
Published: January 2015

La1-xSrxMO3 nanoparticles have attracted increasing interest to material sciences due to their tunable Curie temperature (Tc), superparamagnetic nature and electrical properties, which could be utilized in magnetic hyperthermia treatment. However, La1-xSrxMO3 nanoparticles are toxity to biomolecules and very sensitive to oxidation because of their higher chemical reactivity. The surface modification could enhance stability, dispersibility and compatibility of La1-xSrxMO3 nanoparticles. This review article will introduce the progress on the synthesis and surface modification of La1-xSrxMO3 nanoparticles in recent years, and then give the perspectives of outlook.
Atomic Study of Semi-Coherent Interfacial Structure at Fe[110]/TMC[001] (TM=V, Nb and Ta) Interfaces
Authors: Li Jin Chun , Song Hong Quan , Wang Jian Wei , Shen Jiang
Published: January 2015

Interfacial potential of Fe [110]/TMC[001] (TM=V, Nb and Ta) are obtained with adhesive energy and the inversion method. The interfacial stability and tensile fracture properties of the semi-coherent interfaces of the Fe [110]/TMC[001] (TM=V, Nb and Ta) are studied based on the interfacial potentials. Results indicated that Fe/VC interface is more stable than the Fe/TMC (TM=Nb and Ta) interfaces.
Surface Spot Defects Inspection of Multi-Crystalline Silicon Wafers Based on HALCON
Authors: Wu Xiao Song , Miao Rui , Si Yu Dong , Lou Cheok Man , Xu Duan Xia , Chu Xue Ning
Published: January 2015

As a common kind of surface defects on multi-crystalline silicon solar cells (about 65% of total defects). Based on HALCON image processing library, an automatic silicon wafer surface spot defects detection and classification system has been developed: captured color images via CCD image sensor, located wafers and spots, extracted the spot features, computed and separated the qualified regions from the unqualified ones by SVM classifier. The experimental result showed a high accuracy of 95.7% and fast image analyzing and classifying process (less than 600ms).
Study on Pavement Performance of High Volume Reclaiming Asphalt Mixture
Authors: Huang Wei Rong , Tan Ming
Published: January 2015

It was based on laboratory test, in order to study on the high temperature stability, water stability and low-temperature crack resistance of AC-16 reclaiming asphalt mixture with different proportion of old material, this test takes into account 9 kinds of these asphalt mixture. The results show, with the old material blending ratio increased, the high temperature stability of asphalt mixture changed for the better, water stability and low-temperature crack resistance deteriorated. The pavement performance meet the requirements of secondary road or less, when old material content is within 70%. The research results provide reference for the application of reclaiming asphalt mixture.
A Study on Factors Influencing Hydration Heat Process of Ceramisite Cellular Concrete
Authors: Fang Shan Qi , Qu Tie Jun , Shi Yun Xing , Ni Kun , Geng Ji Chuan , Zhang Yan Gang
Published: January 2015

Ceramisite cellular concrete is a kind of energy-saving materials, which has many advantages, such as low self-weight, better insulation and so on. This paper describes an experimental study of hydration heat process .It proved that the ambient temperature, the amount of fly ash and silica fume influence hydration speed apparently and compressive strength of the concrete.
The Thermal Deformation of Cement-Based Material at Low Temperatures
Authors: Zhang Nan , Liao Juan , Zhang Tao , Ji Wen Zhan
Published: January 2015

Thermal deformation of concrete at low temperature expands from-20°C to-50°C and contracts from-30°C to-10°C. Based on previous studies, the paper tries to explain the deformaion trend by analyzing freezing point of bulk solution and pore solution in saturated hardened cement paste. The result shows that it is critical to thermal deformation of cement-based materials at low temperature that pore solution in the pores smaller than 8 nm freezes.
Utilization of Steel Slag as Aggregates for OGFC-13
Authors: Zhou Xu Lin , Hou Hao Bo , Li Can Hua , Wang Wei Xin , Zhou Min
Published: January 2015

We propose a new method to make OGFC-13. By this method we select steel slag as coarse aggregate (whose diameter is bigger than 4.75mm) and limestone as fine aggregate, using the SBS modified asphalt to make OGFC-16. The Mix Proportion is 1#(19-13.2mm,steel slag):2#(13.2-9.5mm, steel slag):3#(9.5-4.75mm, steel slag):4#(4.75-0mm, limestone):mineral powder=13%:28%:45%:13%:1%. The optimal asphalt content (OAC) is 4.5%, the polyester fiber content is 0.3%, and the steel slag content reaches 86%. The increase of the amount of asphalt and polyester fiber doesn’t help to save costs. When the asphalt content is optimum, the run-off loss and Cantabro scattering loss satisfy the Chinese regulatory requirements. By Marshall Stability test, we find that the Marshall stability of OGFC-13 reaches 9.8kN, superior to China's traffic regulations. The water permeability coefficient of OGFC-13 is 37.0, which means that OGFC-13 has a strong water seepage performance. In a word, OGFC-13 made by our method can guarantee the driving security of the long-term use of the road and save a lot of road maintenance costs.
Preparation and Photocatalytic Property of Cubic WO3
Authors: Shang Fu Liang , Yang Hai Tao , Gao Ling
Published: January 2015

The cubic WO3powder was prepared by sol-gel method with WCl6as the soure of tungsten and P123as the structure-directing agent. The crystalline phase and microstructure of the powder were characterized through TG-DSC, XRD and SEM techniques, respectively. It was found the powder annealed at 250°C for 4h mainly was cubic WO3with a little monoclinic phase. The SEM micrographs revealed the powder has a petal shape with about 200 nm mean particle diameter. The photocatalytic activity of the powder was evaluated by methyl orange as mode compound to photocatalytic degradation under UV light irradiation. The results show the cubic WO3powder has much higher photocatalytic activity than the monoclinic phase.
Electromagnetic Properties of Organic Magnetic Prepolymer Containing Cobalt Phthalocyanine Ring
Authors: Wei Jun Ji , Wang Zi Cheng , Tang Hai Long , Liu Xiao Bo
Published: January 2015

A new kind of organic prepolymer containing cobalt phthalocyanine ring (Co-FOM) was prepared by reaction from ferrocenyl organic magnetic prepolymer (FOM) and cobalt chloride. The structure of Co-FOM was characterized by Fourier transform infrared spectroscopy (FTIR) and ultraviolet-visible spectrophotometry (UV-vis). The magnetic properties of Co-FOM exhibited stronger magnetism than FOM at room temperature. The maximum saturation magnetization of Co-FOM reached to 15.8 emu/g at the magnetic field of 5000 Oe. Meanwhile, Co-FOM had one resonance peak for dielectric loss and two resonance peaks for magnetic loss in 0.5-18 GHz. Furthermore, this kind of magnetic material had a strong reflection loss at higher frequency (around 17 GHz). So Co-FOM will have potential application in electromagnetic shielding area.
Effects of Reductive Conditions on the Electrochemical Properties of LiFePO4/C Derived by Fe3+ Sources
Authors: Lu Yan Wen , Ge Yu , Tang Yue Feng
Published: January 2015

A one-step carbon thermal method was used to prepare LiFePO4/C particles by using normal Fe2O3, LiH2PO4and sucrose as raw materials. The effect of H2content in the sintering atmosphere of N2on the morphology and the electrochemical performance were investigated. LiFePO4/C materials were characterized by X-ray diffraction, scanning electron microscopy and the elemental analyzer. The results show that the precursor sintering under the atmosphere of 8%H2+N2exhibits the highest electrochemical capacity (162.3 mAh/g at 0.1C) .
Electrochemical Behavior of Mg in H3PO4 and Phosphating Solution
Authors: Huang Dao Bing , Tu Yuan Qiang , Hu Ting , Song Guang Ling , Guo Xing Peng
Published: January 2015

The electrochemical behavior of pure Mg in H3PO4 acid (0.42 M) and phosphating solution (0.42 M H3PO4+0.34 M ZnO) was investigated through electrochemical impedance spectroscopy (EIS), potentiodynamic polarization curve and XRD measurements. The results show that Mg has higher corrosion resistance in the phosphating solution than that in the H3PO4 acid which may be due to the relative protective phosphating film on the surface.
Preparation and Performance of Fly Ash Brick
Authors: Chen Jian Bo , Li Pei Xin , Mu Yan , Ma Hong Xiao , Ren Xiao Lin
Published: January 2015

This paper uses the industrialization production device to study the factors that affecting the performance of fly ash products. Through adopting the appropriate material ratio and technological parameters, the load-bearing standard bricks with large admixing amount of fly ash were successful developed. The mixing amount of fly ash has reached about 50%, and the bricks were got the production application in the industrialized device which annual output is 400 million pieces. The product performances are referred to the requirements specified in JC 239-2001, and the compressive strength reach 16.6 MPa and the breaking strength reach 3.8 MPa. The product has the low thermal conductivity and qualified freeze-thaw resistance, dry shrinkage. The products were got widespread popularization and application in the building construction of Qinghai-Tibet Plateau.
Molecular Dynamics Simulation on Liquid Nucleation in Ideal Silicon Crystal upon Melting
Authors: Zhang Shi Liang , Gao Wei
Published: January 2015

Liquid nucleation in an ideal silicon crystal is studied in the framework of Lindemann criteria by using molecular dynamics simulations. Lindemann parameter is traced during the transition. It is found that when Lindemann parameter reaches a critical value δL*=0.328, liquid emerges, and when 9.4% atoms in the crystal exceeds the critical value, a complete melting is achieved.
A Survey of Hydrogen Peroxide Bleaching and FAS Bleaching of Liquid Package Recycled Pulp
Authors: Xu Zong Juan , Liu Yu , Wang Zhen
Published: January 2015

This document demonstrates how to affect the brightness of liquid package recycled pulp by hydrogen peroxide bleaching and FAS beaching. The optimum H2O2 bleaching process conditions: 8% H2O2, 4% NaOH, bleaching temperature 80 °C, bleaching time 1.5h. The best FAS bleaching conditions was FAS dosage of 0.5%, NaOH dosage of 0.25%, bleaching temperature at 80 °C, time for 30min. And bleaching had no adverse effect on the performance of bleached pulp fiber.
Mo Behavior in Mn-Zn Ferrites at High Temperatures Part 1: Exploration of Chemical States of Mo in Mn-Zn Ferrites
Authors: Lin Yang Yi , Zhao Xu , Cai Ya Qiu , Zheng Fu Nan , Huang Jin Tao
Published: January 2015

Possible chemical states of molybdenum in Mn-Zn ferrite at high temperatures were investigated by experiments and thermodynamic calculations. It is found that solid or liquid MnMoO4(s,l) is the main Mo-containing phase during the sintering process of Mn-Zn ferrite up to about 1623 K, even if MoO3is employed as the additive. When temperature is higher than the melting point of MnMoO4, Mo in Mn-Zn ferrite tends to evaporate in form of Mo3O9(g) from thermodynamic point of view.
Structure and Stability of Osn (n=2-10) Clusters
Authors: Zhang Xiu Rong , Zhang Fu Xing
Published: January 2015

Geometric structure of Osn(n=2-10) clusters are optimized by using Density functional theory (DFT) in DMOL3 package. For the ground-state structure, relative stability are analyzed. The results show that: the ground-state structures of the cluster are plane structure when n=2-4, but the ground-state structures are stereostructure when n≥5. There exhibits the odd-even oscillation effect in stability and Os8cluster has the highest stability.
Preparation of Molybdenum High Speed Tool Steels with Addition of Niobium Carbide by Powder Metallurgy Techniques
Authors: de Araújo Filho Oscar Olimpio , Antonello Rodrigo Tecchio , Gonzalez Cezar Henrique , Urtiga Filho Severino Leopoldino , Filho Francisco Ambrozio
Published: January 2015

High speed steels processed by Powder Metallurgy (PM) techniques present better mechanical properties when compared with similar steels obtained by the conventional process of cast to ingot and hot working. PM techniques produce improved microstructures with smaller and better distribution of carbides. Liquid phase sintering high speed steel seems to be a cheaper processing route in the manufacturing of tool steels if compared to the well-known and expansive hot isostatic pressing high speed steels. The introduction of niobium as alloying element began with the object of replacing elements like vanadium (V) and tungsten (W). Phase liquid sintering consists in a manufacturing technique to process high speed steels by powder metallurgy. The aim of this work of research is to process and obtain AISI M2 and M3:2 with and without the addition of niobium carbide by high energy milling, cold uniaxial compaction and vacuum sintering in the presence of a liquid phase. The powders of the AISI M2 and M3:2 were processed by high energy milling adding a small quantity of niobium carbide (6% in mass), then the powders were characterized by means of X-ray diffraction (XRD) and scanning electron Microscopy (SEM) plus energy dispersion spectroscopy (EDS) in order to evaluate the milling process. The powders of the AISI M2 and M3:2 with the addition of niobium carbide (NbC) were uniaxially cold compacted and then submitted to vacuum sintering. The sintered samples had their microstructure, porosity and carbide distribution observed and evaluated by means of Scanning Electron Microscopy (SEM) and the mechanical property of hardness was investigated by means of Vickers hardness tests. At least five samples of each steel were investigated.
Nanostructured Al Powder Obtained by High Energy Ball Milling at Ambient and Cryogenic Temperatures
Authors: de Lira Heronilton Mendes , Rodriguez Pilar Rey , de Araújo Filho Oscar Olimpio , Gonzalez Cezar Henrique , Filho Severino Leopoldino Urtiga
Published: January 2015

High performance nanostructured light metals and alloys are very interesting for replacing conventional heavier materials in many industrial components. High Energy Ball Milling and Cryomilling are useful techniques to obtain nanocrystalline powders. In this work the effect of several milling conditions such as rotation speed, time, ball to powder ratio and temperature on the crystallite and particle size and morphology in pure aluminum are presented. X-Ray Diffraction, Laser Diffraction and Scanning Electron Microscopy are used. High energy ball milling at ambient and cryogenic temperature of Al powders rapidly leads to a nanometer size down to about 35 nm. High ball to powder ratio promotes both low crystallite and particle size. Small crystallite size like 18 nm and particle size as 4 μm were achieved in the most energetic conditions at ambient temperature. Isopropyl alcohol used as liquid media and protective atmosphere has a strong influence on the results depending on the milling temperature of Al.
Experimental Analysis of Behavior in TiO2 Nanoparticle Suspension
Authors: Souza Maryana Antonia Braga Batalha , de Souza Forster Adriana , Oliveira Mabelle Biancardi , de Castro José Adilson
Published: January 2015

The deposition of TiO2 nanoparticles in the environment has been systematically investigated; this is due to the use of nanosized titanium dioxide (TiO2) in a variety of consumer products such as sunscreens, cosmetics, paints and surface coatings as well as the environmental decontamination of air, soil and water. It is the generalized use which increases the concern that the nanoparticle TiO2 could pose a risk to ecosystems and humans. In this context, this paper aims to characterize different suspensions of nanoparticles of titanium dioxide. Although these particles are already incorporated in a wide range of products, the evaluation of their behavior and its effects on the environment and health start to grow now. So this paper aims to conduct a study of the behavior of TiO2 nanoparticles in aqueous suspensions. The study encompasses TiO2 solutions with ultra pure water with and without added NaCl, landfill leachate and tap water. The results obtained showed that the addition of NaCl in the solution increases the size of the TiO2 nanoparticles, showing that the sodium chloride functions as a binding agent when in contact with nanoparticles of titanium dioxide.
High-Energy Ball Milling and Sintering of Ti-2Ta-22Si-11B and Ti-6Ta-22Si-11B Powders Mixtures
Authors: Ferreira Lucas , Alkmin Luciano Braga , Ramos Érika C.T. , Nunes Carlos Angelo , Ramos Alfeu Saraiva
Published: January 2015

The milling process of elemental Ti-2Ta-22Si-11B and Ti-6Ta-22Si-11B (at-%) powder mixtures were performed in a planetary Fritsch P-5 ball mill using stainless steel vials (225 mL) and hardened steel balls (19 mm diameter). Ball-to-powder weight ratio of 10:1 and a rotary speed of 300 rpm were adopted, varying the milling time. Wet milling (isopropyl alcohol) for 20 more minutes was used to increase the yield powder in to the vial. Following the Ti-Ta-Si-B powders milled for 600 min were heat-treated at 1100°C for 1 h in order to obtain the equilibrium structures. The milled powders and heat-treated samples were characterized by X-ray diffraction, scanning electron microscopy, and energy dispersive spectrometry. Supersaturated Ti solid solutions were formed during ball milling of Ti-Ta-Si-B powders while that the Ti5Si3 phase was formed after milling for 620 min of the Ta-richer powder mixture only. The particles sizes were initially increased during the initial milling times, and the wet milling provided the yield powder into the vials. A large amount of pores was found in both the sintered samples which presented the formation of the TiSS,(ss-solid solution) Ti6Si2B and TiB.
Fast Pyrolysis of Soy Hulls in a Fluidized Bed Reactor: Main Components of the Bio-Oil
Authors: de Oliveira Tiago José Pires , Cardoso Cássia Regina , Ataíde Carlos Henrique
Published: January 2015

The fast pyrolysis is an efficient and promising process of thermal decomposition. The process consists in the reaction of organic materials in the total or partial absence of oxygen to produce condensable vapor, non-condensable gases and char. Bio-oil is generated after vapor condensation and it can be converted into fuels and/or chemicals. Fast pyrolysis of soy hulls was conducted in a batch reactor fluidized bed, made of stainless steel, with internal diameter of 78 mm and 1069 mm height. The fast pyrolysis of soy hulls, mixed with inert (sand), was carried out at approximately 550 °C. Atmosphere with high nitrogen concentration was used. The present study aimed to investigate the chemical composition of the soy hulls bio-oil using gas chromatography and mass spectrometry techniques.
Study of the Use of an Anionic Collector in the Mineral Wastewater Treatment by Dissolved Air Flotation
Authors: Santos M.A. , Santana R.C. , Capponi F. , Nery M.C. , Ataíde C.H. , Barrozo Marcos A.S.
Published: January 2015

The use of recycled water in the apatite flotation may result in losses to the process performance due to the presence of ions, residual reagents, finely particulate material, etc. The dissolved air flotation (DAF) has been shown an efficient technique in the wastewater treatment in the removal of these pollutants. The use of anionic collector in DAF process is based on the reaction that occurs between the soybean oil soap (apatite collector) with the calcium present in the apatite lattice making its surface hydrophobic. Therefore, the collector can be an auxiliary in the water softening besides improving the hydrophobicity of the particles to be collected. Thus, this study was aimed at evaluating the effect of an anionic collector used as an auxiliary in the dissolved air flotation process. A central composite design (CCD) was proposed to evaluate the concentration of collector and the effect of pH value on the removal efficiency of calcium, magnesium, fluoride, phosphorous and turbidity present in a wastewater from a fertilizer industry. The results showed a good removal of the contaminants which guaranteed a better quality of water to the process of phosphate rock concentration.
High-Energy Ball Milling and Hot Pressing of the Ni-48Ti-2Sn and Ni-45Ti-5Sn Powder Mixtures
Authors: Kayano Leandro Koji , Murusawa Daniel , Cortez Pereira Gilda Maria , Ramos Alfeu Saraiva
Published: January 2015

This work presents the results on the high-energy ball milling and hot pressing of Ni-48Ti-2Sn and Ni-45Ti-5Sn (at-%) powder mixtures. The milling process was performed in a planetary ball mill using stainless steel vial (225 mL) and hardened steel balls (19 mm diameter), rotary speed of 300 rpm, and a ball-to-powder weight ratio of 10:1. Samples were collected into the vial after different milling times: 60, 180 and 300 min. In the sequence, wet milling (isopropyl alcohol) was adopted up to 720 min in order to increase the powder yield into the vials. The as-milled and hot-pressed samples were characterized by X-ray diffraction, electron scanning microscopy, and energy dispersive spectrometry. Results indicated that the ductile particles were promptly cold-welded during the initial milling times. XRD patterns of the Ni-48Ti-2Sn powder mixture indicated that the peaks of Ni, Ti and Sn disappeared after milling for 3h. Following, peaks of NiTi and Ni4Ti3 were preferentially formed during milling of Ni-Ti-Sn powders. A large amount of fine powders was yielded into the vial after wet milling for 720 min only. No significant carbon or oxygen contamination was detected by EDS analysis. Hot pressing produced homogeneous and dense samples which presented microstructures containing a large amount of the NiTi compound.
Influence of the Temperature in the Direct Forming Laser Process of 316L Stainless Steel with CO2 Laser
Authors: Santos C.L. , Vasconcelos G. , Oliveira H.S. , Oliveira L.G. , Azevedo J.F. , Riva R.
Published: January 2015

This study shows the influence of the temperature in the Direct Forming Laser process (DFL) of 316L stainless steel metal powder. Results shows that an increasing in the sample surface temperature can improve the laser beam absorption in the DFL process. A pre-heating in the substrate and in the powder contributed to decrease the time to reach the melting point and to improve the surface roughness. This effect was investigated with constant lasers parameters (scanning speed and intensity) and a heating in the samples in the temperature range of 20o to 200o C. It was possible to evaluate the DFL process and to optimize the quality of the sample surface roughness. These results will benefit the knowledge of the DFL technology that can be applied in the development of turbine blades.
Selective Laser Sintering of Different Powders of Co-Cr-Mo
Authors: dos Santos Claudinei , da Silva Paula Cipriano , de Paula Luciane Carvalho , Habibe Alexandre Fernandes , Lins Jefferson Fabrício Cardoso , Soares Walter
Published: January 2015

In this work, different commercial Co-Cr-Mo powders were used in selective laser sintering. Commercial powders with particle size distribution between 5 and 50μm were sintered by laser sintering, and characterized. The samples were characterized by X-ray diffraction, indicating Co as the only crystalline phase. Relative density was measured by Archimedes method showing values between 90 and 96% of TD, depending on the powder used. Scanning electron microscopy performed on the cross section of the sintered samples, indicates that the microstructural features are similar, but the surface finish of the samples differ significantly due to the morphology and size distribution of the starting powders used.
Characterization of the AISI 304 Alloy Treated in a Large Vacuum Chamber PIII System with a New HV Pulser
Authors: Ribeiro da Silva Ataide , Ueda Mario , Rossi José Osvaldo , da Silva Matheus Moraes N.F. , do Santos Maciel Mayse , Pichon Luc
Published: January 2015

Plasma immersion ion implantation (PIII) method is often used to cleaning and enhancing mechanical properties of the surface of materials. In this work, the AISI 304 was treated in a PIII system to improve tribological and wear resistance properties. The new HV pulser was prepared to reach high average power (10 kW) using solid-state technology and a pulse transformer rather than using a conventional one based on hard-tube tetrodes with HV storage capacitors. For preliminary tests, low-density nitrogen plasma and pulses of 10 kV, 30μs width, and 1 kHz were used. A larger vacuum chamber used (600 liters) is very important for treating large area components and for batch processing. This is necessary in industrial applications and in cases that require high quality processing as in spatial or medical components. Stainless steel support was used to hold the samples in our case. XRD, SEM, and pin-on-disk surface diagnostics were used for investigation and characterization of the treated surfaces.
Evaluation of Heat Absorption in Iron Ore Using Microwave Energy Source
Authors: Silva L.M. , Nascimento M. , Mota I.O. , Fernandes Marcio T. , Castro J.A.
Published: January 2015

The phosphorus content has significant effect on the steels quality and their applications. The iron ore resources around the world has continuously increased the amount of phosphorous due to the increase of the mining volume with less sterile generation aiming at the efficient utilization of the mining resources, as consequence larger amount of materials with high iron content but with higher phosphorous has been incorporated in the mining body. An alternative to enhance the mining efficiency is to perform a pre treatment of part of the mining body and subsequent blending to attain the acceptable phosphorous in the steelmaking. A viable alternative for reducing the phosphorus content of these residue is to use the acid leaching process which is considered an economical process for the dephosphorization of the iron ore, however, depending on the way the element phosphorus is contained in the ore it will demand additional energy. The objective of the present paper is to study the effective heating and cooling rates of iron ore using microwave energy and its subsequent cooling effect in a short period (thermal shock). Through the X-ray diffraction analysis and applying the Rietveld method it has been possible to demonstrate the mineralogical composition of the iron ore samples and the effect of rapid heating and cooling suitable to promote the fissure formation, thus enhancing the leaching efficiency. The scanning electron microscopy (SEM) was used to analyze the structure of ore due to the effect of its heating and cooling rates.
Friction and Wear Behavior Evaluation of DLC Films Grown in Multilayer of Carbon and Silicon
Authors: da Silva Patrícia Cristiane Santana , Martins Gislene Valdete , Corat Evaldo José , Trava-Airoldi Vladimir Jesus
Published: January 2015

Excellent tribological properties of hard materials surface are desirable in several sectors of industry. Diamond-like carbon (DLC) coatings are well known for their low friction, excellent wear resistance, and high hardness. In this work, DLC films were deposited on AISI M2 steel using a modified PECVD pulsed-DC discharge. Multilayer of carbon and silicon were grown, alternately. Samples were produced with different layer thickness for carbon and silicon, and the same parameters for each material layer, in order to investigate friction coefficient in each layer, evaluate rate deposition variation and the gradient behavior of different layers. Raman spectroscopy was used to verify the structural arrangement of carbon atoms. The films were also characterized by scanning electron microscopy and EDX. Tribological tests were performed to observe adhesion between layers and substrate, friction, and wear. The results showed the variation of friction coefficient and that deposition rate declines when increasing number of layers.
Interface Evaluation of MCrAlY Powder Bond Coat on 316 SS Processed with Laser Irradiation
Authors: Teleginski Viviane , Chagas Daniele C. , de Oliveira Luis Gustavo , de Vasconcelos Getúlio
Published: January 2015

As aircraft and thermoelectric turbine blades work in aggressive environments (high temperatures and pressures), they are exposed to oxidation reactions. Ceramic coatings are employed to increase the turbine work temperature (improving its performance) and a bond coat (BC), base of particulate material of Ni-Cr-Al powders, which assure a good adhesion, gradual decrease in thermal expansion coefficient between the metallic substrate and the ceramic top coat, avoiding the oxidation effect in the metallic substrate. This research aims the study and comparison of two different deposition process routes of particulate materials of BC (MCrAlY) on AISI 316 stainless steel substrate. In the first case, the BC powder was pre-deposited by segregation method and irradiated by a CO2 laser beam. In the second case, laser surface texturing was done on the stainless steel surface by a Yb: fiber laser beam, the BC was deposited by the same method, and further, irradiated by a CO2 laser beam. The main focus of this work was to evaluate the resulting interface for both mentioned cases. For this propose, characterizations were made using the techniques of optical microscopy and roughness measurements. In the first case, homogenous layers of bond coat were obtained. Optical microscopy suggest the formation of a metallurgic bonding between the substrate and the MCrAlY. For the laser surface texturing, the surface roughness can be adjusted by the laser beam parameters.
Analysis of Surface and Profile of Pits in Austenitic Stainless Steel AISI 310S by Optical Microscopy
Authors: Ribeiro Rosinei Batista , de Jesus Silva José Wilson , de Oliveira Hein Luis Rogerio , Codaro Eduardo Norberto , Matias Nelson Tavares
Published: January 2015

Pit morphology on sensitized 310S stainless steel has been studied using an image processing method based on reflected light microscopy (profile and surface). Salt Spray test has been used to induce the pitting corrosion. Morphological pits character do not depend on sensitization heat treatments here applied. Nucleation rates and growth may be associated with quantity and distribution of chromium carbides. This being so, condition I (heating up to 1065o C during 1 h and air cooling) and condition II (heating up to 1065o C during 1 h and air cooling followed by reheating up to 670°C during 5 h and again air cooling) are the most susceptible to pitting, in particular the first one. In these two conditions, pits are nucleated in grains and in grain boundaries, while in condition III (heating up to 1065o C during 1 h and air cooling followed by reheating up to 620o C during 24 h and again air cooling), pits are preferentially nucleated in boundaries of small grains. Thence, pits usually grow more rapidly in depth than in width, being able to occur partial or total grains separation. Pits are mainly hemispherical, near-hemispherical, near-conical and near-cylindrical without significant geometric transition associated with an increasing exposure period.
Superparamagnetic Iron Oxide Nanoparticles for Magnetic Hipertermia: Synthesis, Surface Modification by Polyethylene Glycol and Characterization
Authors: Sampaio da Silva Fernanda A. , Rojas Edwin E.G. , Romero Sérgio , de Campos Marcos Flávio
Published: January 2015

Nowadays, superparamagnetic iron oxide nanoparticles are an important tool for cancer treatment, such as magnetic hyperthermia. The goal is heating diseased tissue and then tumor cells are destroyed. Magnetic nanoparticles are promising mainly because they have specific ability to reduce side effects. However, for in vivo applications, nanoparticles need to be coated by a biocompatible material. In this work, nanoparticles are coated by PEG (biocompatible polymer). Samples were produced by coprecipitation process. Information about particle size, magnetic properties and crystallinity were obtained.
Effect of Ball-Powder Ratio in the High-Energy Milling of 66%Co-28%Cr-6%Mo Dental Alloy
Authors: dos Santos Claudinei , Habibe Alexandre Fernandes , Rodrigues Durval , Minatti José C. , Lins Jefferson Fabrício Cardoso , dos Santos Luis Alberto
Published: January 2015

In this study, the effect of ball/powder ratios for grinding particles of a dental alloy consisting of 66%Co-28%Cr-6%Mo was investigated. Metal powders were obtained from SPEX mill, with tungsten carbide balls, setting the milling time to 60 minutes, 50% of volume of grinding vessel filled with powder and argon inert atmosphere. The ball/powder ratio was varied between 4:1, 6:1, 8:1, 10:1.The powders were characterized by XRD indicating Co as only crystalline phase present, which indicates that Cr and Mo enter into solid solution with the matrix Co. Measurement of crystallite size conducted using the Scherrer equation indicate the crystallite size about 10 to 6nm, due to the increase of the ball/powder ratio of 4:1 to 10:1. The morphology of the milled powders were analyzed by scanning electron microscopy (SEM) and indicate that the agglomerates created by the grinding process must have average sizes varying between 100μm and 200μm with the modification of the ball/powder.
NdFeB Type Magnets Produced by Spark Plasma Sintering
Authors: Campos M. Alberteris , Vicente N. , Machado I.F. , de Souza K.S.T. , Rodrigues D. , de Campos Marcos F.
Published: January 2015

The shortage of dysprosium as an alloying element has directed the research on the grain size refining of NdFeB, since higher coercivities can be obtained by decreasing the grain size, without Dy addition. The Spark Plasma Sintering (SPS) is a consolidation process which allows densification at lower temperatures and shorter dwell times of sintering, thus avoiding the grain growth. Therefore, the typical temperature of sintering of NdFeB magnets can be decreased from 1050°C to around 800°C, as it was evidenced by means of SPS shrinkage curves and the high densified microestructure obtained in this work.
Thermal Analysis Investigation of NdFeB Bonded Magnets
Authors: Rodrigues Daniel , Concílio Gilberto V. , da Rocha Elisa Pinto , de Castro José A. , de Campos Marcos F.
Published: January 2015

NdFeB bonded magnets are produced by compression molding and curing. Typical raw materials are mixtures of epoxy resin and Nd2Fe14B flakes, produced mostly by melt spinning. The curing temperature should be adjusted for obtaining the best in terms of mechanical properties without overheating the pressed component. High curing temperatures can strongly oxidize Nd, generating more heat, and burning may occurs. The curing reaction is exothermic, thus the actual curing temperature will depend on the cured mass. This paper investigates this heating generation during curing, using DSC experimental apparatus.
Squareness of NdFeB Stoner-Wohlfarth Hysteresis
Authors: de Campos Marcos Flavio , da Silva Fernanda A.S. , de Castro Jose Adilson
Published: January 2015

Hysteresis curves were calculated according the Stoner-Wohlfarth (SW) model using values of K2/K1 from zero up to 0.25 (where K2 is the 2nd order anisotropy constant and where K1 is the 1st order anisotropy constant). The SW calculations assume Nd2Fe14B nanocrystalline magnets with single domain particle size (grain diameter less than 150 nm). The effect of K2 on several index of merit of magnets as BHmax and squareness are discussed. As a general result, increasing K2, the intrinsic coercivity increases. However, the increase of K2 almost does not improve the BHmax of isotropic magnets. It is found that the effect of the K2/K1 ratio is coupled with the effect of texture, i.e., the effect of K2 is more significant for pronounced texture.
Modeling the Neodymium Metallic Reduction from Molten Salts
Authors: de Castro Jose Adilson , de Campos Marcos Flavio
Published: January 2015

A model for simulating the reduction of metallic neodymium from molten salts is presented. The model was formulated with basis on the Navier-Stokes equations coupled with the Maxwell's relations. The model is useful for predicting optimum parameters of processing, as for example cell geometry and current density.
Virtues and Weakness of Brown Micromagnetics
Authors: de Campos Marcos Flavio
Published: January 2015

Micromagnetics and its particular case, the Stoner-Wohlfarth model, are reviewed. The possibility of occurrence of curling is discussed. The use of the Felix Bloch approximation for exchange energy description should be avoided. A tensor 3x3 has to be used for appropriate evaluation of the exchange energy in phases with less symmetry, as Nd2Fe14B, Sm2Co17 and SmCo5. The assumptions used in classic Brown micromagnetics make it less suitable for phases with high magnetocrystalline anisotropy. The role of the exchange term in the Stoner-Wohlfarth Callen-Liu-Cullen model is clarified.
Predictions of Xylene Adsorption on Agglomerated Activated Carbon Pellets in a Fixed Bed Column
Authors: de Oliveira da Mota Izabel , da Silval Leonardo Martins , de Castro José Adilson
Published: January 2015

Volatile organic compounds (VOCs) are an important category of air pollutants and adsorption has been widely recognized as an effective means of controlling emissions to the atmosphere. The current study used theoretical model to analyze the rate of xylene adsorption from inert gaseous stream on the granular activated carbon in a fixed bed column under varying operating conditions. The model considers the inner diffusion of VOC into the activated carbon particles. Experimental results of another author study were used to validate the present model and the methodology proposed to determine the xylene concentrations at the outlet of the column and corresponding inner particles.