bluuebunny/crossref_metadata_2025 huggingface dataset:
A Research of Electromechanical Products Green Design Based on Voice of Customer
Authors: Lou Xi Yin
Published: January 2015

The customer is the starting point for green design of electromechanical product demand, also the bridge of connecting to the market and the mechanical and electrical product development process. Enterprises effectively obtain and understand customer needs, and accurately define the demand information of mechanical and electrical products in the design process, which is the necessary precondition for the successful design of mechanical and electrical products in the global market environment. The designer obtains accurately and effectively information of demand of mechanical and electrical products, which is an important link of product design process. It will also directly affect the subsequent steps in the process of product development. Therefore, all aspects of mechanical and electrical products manufacturing enterprises work should depend on customer demand. To meet the design idea of customer demand should be fully integrated into every link in the development of mechanical and electrical products. Enterprise can not only shorten the time of mechanical and electrical products, but also have a significant impact on the design of mechanical and electrical products quality.
Research on Submerged Logistics Carrying AGV Used in E-Commerce Distribution Center
Authors: Li Jun Tao , Yuan Hang , Zhang Han Bin
Published: January 2015

With quick development of electronic commerce, the demand for its logistics capability grows gradually. Traditional logistics operation model of e-commerce distribution center can’t meet the requirement of electronic commerce logistics which features multi-catalog and small batch. It is urgent to develop intelligent and automatic technology which is helpful for improving capability of logistics processing. With the premise of economy, we research and develop a set of submerged logistics AGV equipment which is based on the thought of warehouse sorting integration, automation problem in e-commerce distribution center, and we aim at realizing the concept of moving cargo to human automatically.
Cloud Logistics Path Optimization Based on Ant Colony Algorithm
Authors: Chen Zhi Gao
Published: January 2015

Cloud Manufacturing is developed in the cloud computing, which is based on the idea of "Made in service" recently. Cloud manufacturing mode connect all sorts of manufacturing resources and capability together and form standard manufacturing services which customers can obtain according to their demand at any time. Logistics mode should coincide with manufacturing mode for the certain correlation between logistics and manufacturing process,so the production and development of cloud manufacturing mode had the logistics mode reformed. In this paper we present a cloud manufacturing service composition method considering execution reliability based on ant algorithm, to optimize the use of composite service execution path to save the costs.
Simulation Study of Jet Formation and Depth of Penetration against Steel Targets at Different Cone Angles Using Autodyn-2D Hydrocode
Authors: Mukhtar A. , Huang Zheng Xiang , Malik A.Q. , Zu Xu Dong , Xiao Qiang Qiang
Published: January 2015

Jets obtained from shaped charge at different cone angle are simulated using Euler solver in Autodyn-2D Hydrocode against a 56mm-diameter of the charge. An OFHC copper liner of thickness 0.8mm and 54 mm-diameters is used for jet formation analysis. Point detonation method is used for Charge ignition. The simulation results are presented at 30 micro-second after initiation. Energy behavior is predicted at different obliquities. Numerical simulations are compared with the existing experimental results for liner angle 60. The depth of penetration and volume of the crater produced is measured. It is observed that simulation results are in good agreement with the experimental results. Flash X-ray Radiography was used for image capturing. It is observed that kinetic energy of the jet decreases as angle increases, also total energy of the explosive increases and hence the Ratio of the K.E of the jet to the total energy of the explosive decreases as the angle increases. The volume of the crater produced in steel at 65° has the highest value among the jets considered, so it can be used in oil well perforation also.
Antioxidant Activity of Silk Fibroin Peptide Hydrolyzed by Pancreatin
Authors: Zhu Zhen , Yin Hua , An Yan
Published: January 2015

This research adopts the pancreatin hydrolysis of silk fibroin active peptide, evaluate the antioxidant activity of hydrolysates. In the process of hydrolysis of silk fibroin, by measuring the amino nitrogen content of neutral formaldehyde titration method. Find the amino nitrogen content gradually stabilized at around 0.37g/L, and superoxide free radical scavenging rate changing with time fluctuation trend, superoxide free radical scavenging rate to a maximum of 65.03% at 220min.The use of silk fibroin hydrolysis process optimization,reaction time 160min, enzyme concentration4% , substrate concentration 20mg/ml, pH 8, temperature 38°C. The hydrolysis process under the hydrolysate on superoxide radical scavenging rate of 72.73%. The scavenging rate of hydroxyl radical is 47.24%. Red blood cell hemolysis induced by H2O2 inhibition rate was 24.30%.
Theoretical Study of Iron Heterogeneous Growth on the Surface of C60 Molecule
Authors: Liu Qi Cheng , Li Yun Fang
Published: January 2015

Direct molecule dynamics (MD) simulations have also been performed to study heterogeneous nucleation and growth of iron on C60 molecule. The grown mechanism of this crystallization process was explored. The results indicate that 92 iron atoms attach to C60 molecule surface can form new covalent bond, forming a closed regular icosahedron. More atoms grow in layer to form bigger regular closed clathrate base on the structure of former one. As increase of atoms number, there will appear some crystal faces.
The Effect of Surfactants on the Dispersion of Carbon Nanotubes in Water
Authors: Meng Sheng Hao , Yan Jun , Li Hong Guang , Du Shi Guo
Published: January 2015

Dispersion of carbon nanotubes in water largely determines the excellent properties of carbon nanotubes can be fully exhibited in the composite material. Summarizes the characteristics of all kinds of surface active agent, select several can represent various types of surfactant reagents to test and comparing the several kinds of surfactants on the dispersion of carbon nanotubes, and focus on the effects of polyvinylpyrrolidone special molecular structure on the surface of the carbon nanotubes.
Effects of Heterogeneous and Homogenous Laves Phase Precipitation on Creep Rupture Strength of Fe-9Cr-3Co (wt.%) Alloys at 650 °C
Authors: Zhu S. , Yang M. , Song Xin Li , Zhang Z. , Tang S. , Xiang Z.D.
Published: January 2015

The relationship between creep rupture strength and Laves phase precipitation and growth kinetics was investigated at 650 °C for two Fe-9Cr-3Co (wt.%) alloys differing mainly in the amounts of W and Mo added. In the alloy with 3.14 wt.% W added, Laves phase precipitated heterogeneously on grain boundaries and hence had little dispersion strengthening effect. Its stress exponent for rup-ture time became lower in the lower creep stress range tested. In the alloy with 1.31 wt.% W and 3.22 Mo added, Laves phase precipitated both heterogeneously on grain boundaries and homogenously within grains and there was no reduction in stress exponent for rupture time in the whole stress range tested. The Lave phase precipitation kinetics increased with increasing the total amount of W and Mo in the alloys. The differences in stress-rupture time relationship observed between the two alloys were discussed in relation to their differences in the Lave phase precipitation behaviour.
Fatigue Crack Propagation Life Prediction of 2A12 Aluminum Alloy Based on VCCT
Authors: Xi Liang , Zhao Xiu Li , Shang Chong Wei , Kong Guang Ming , Liu Xu
Published: January 2015

The fatigue crack propagation behavior of the prior corrosion 2A12 aluminum alloy fastener involving a central hole was investigated. The virtual crack closure technique (VCCT), is straightforward and not sensitive to the FEA mesh size, was carried out to calculate strain energy release rate and SIFs of AA 2A12 under different stress levels and corrosion years. Based on the VCCT, the simulation carried out to analyze the corrosion fatigue crack growth behavior. It was proved to be convenient to simulate the crack propagation life and the predicted crack growth curve was in good agreement with the experimental results.
Effect of Cu on the Microstructure of 5052 Aluminum Alloy
Authors: Qiao Nan , Liu Xiao Kui , Jiang Xian Quan , Chen Zhi Qian , Li Chun Mei , Che Hong Mei
Published: January 2015

5052 aluminum alloy modified with Cu was prepared, and the microstructure of the alloy was investigated throughly. The results show that, the constituents are identified as α (Al), θ-Al2Cu, S-Al2CuMg, Al6(Fe,Cu), Al7Cu2Fe and Si-rich phases. After homogenization at 460°C for 24 hours, the ternary eutectic phases (α-Al + Al2Cu + Al2CuMg) are almost completely dissolved, and there can be observed more binary eutectic phases (α-Al + Si). In addition, the transformation from Al6(Fe,Cu) to Al7Cu2Fe phase occurs during the homogenization. With the increasing of the homogenization temperature, more Al7Cu2Fe phase forms, while the amount of Al6(Fe,Cu) phase gradually declines.
Experimental Studies on Corrosion Behaviors of Casing Steel N80 in High Salinity of Brine
Authors: Lin Feng , Xu Ming Biao , Mu Yun Long , Wang Lei
Published: January 2015

Brine corrosion can remain a large obstacle to the rehabilitation project of Missan Oilfields in Iraq. To minimizecorrosion risks, the 13-3/8′′ casing steel, N80,has been employed to examine corrosion behaviors in simulated formation water (i.e., brine). The impact factors of corrosion such as temperature, ion contents, exposure time, and pH have been studied. Also, corrosion inhibitors available in brine have been screened by a static weight loss method. The results showed that effects of environmental and operational variables on N80 corrosion are fairly complicated; the corrosion inhibitor, HN-amph, exhibits excellent corrosion inhibition in brine. This work will provide important information for on-site application.
The Influence of Wire Properties on the Quality and Performance of Wire+Arc Additive Manufactured Aluminium Parts
Authors: Gu Jiang Long , Ding Jia Luo , Cong Bao Qiang , Bai Jing , Gu Hui Min , Williams Stewart W. , Zhai Yu Chun
Published: January 2015

Wire+arc additive manufacture (WAAM) is a high build rate process for production of near-net shape components layer by layer. The performance and quality of the deposited metal are heavily affected by the properties of wires, which are the raw materials for WAAM. Therefore there may be higher requirements for the qualities and properties of wires for WAAM than for welding. External surface qualities, micro hardness, composition and microstructures of five ER4043 aluminium wires were investigated in the present research. The results indicate that the internal and external properties of the wires exert great influence on the performance of the WAAM parts.
A Novel Method to Fabricate Polymer Porous Membrane by Hot-Pressing Process
Authors: Wu Xing Yun , Lu Yan Wen , Yang Hua Zhen , Tang Yue Feng
Published: January 2015

A novel method called hot-pressing method of preparing porous membrane was firstly reported in this paper. Compared with other method such as none-solvent induced phase separation method, melt-spinning and cold-stretching method, the hot-pressing method was simple, easy to operate, environment-friendly. First, a silica needle arrays (SNA) template with a hexagonal close-packed structure was prepared by TAFE method. Then the SNA template was used to press into the plastic wrap in order to form the uniform pores. After that, a uniform porous membrane was prepared. The diameter of the porous membrane was affected by the pressure of hot-pressing as well as the hot-pressing temperature.
High Concentration Polymer Flooding Injection Time Optimization of Sub-Layer Reservoir
Authors: Xu Miao , Qiao Hong Yu , Wang Yong Ping
Published: January 2015

Based on the research of experiment content and connecting with the current of Daqing oil field polymer injection condition [1]. We make the following experiment scheme design that focus on the study of polymer injection time. We analyzes the change of the ultimate recovery trend and combines with the change of moisture content and injection pressure indicators. We summarize the change of the polymer injection time under the condition of indoor physical simulation experiment on the influence of ultimate recovery to guide the late oil field polymer injection development plan design [2].
Study on Preparation of Glucose by Poplar Cellulose Enzymatic Hydrolysis
Authors: Ma Zhan Song , Liu Yu , Wang Zhen
Published: January 2015

This paper made the detailed discourse for the study on using cellulase, hemicellulase hydrolysis of poplar fiber raw material to make glucose. The raw material used in this experiment is poplar, cellulase and hemicellulase enzymes are used. Hemicellulase is a complex system, xylose is regarded as the main chain for a lot of hemicellulose. The experiment used dry poplar as raw material, through the ball mill, ground poplar into wood powder. In the experiment, the optimal condition of enzyme hydrolysis of wood powder has been discussed based on reaction temperature, reaction time, enzyme concentration, and the pH value of reaction. Finally, under the optimal condition, use enzyme to hydrolyse wood powder, measure reducing sugar content by the DNS method, and calculate the rate of hydrolysis.
Influences of Laccase Mediator System on Bleachability and Fiber Properties of APMP Pulp
Authors: Wang Hui Mei , Liu Yu , Chen Jia Chuan , Wang Zhen
Published: January 2015

In this research, the laccase mediator system (LMS) was used to modify the unbleached triploid populus tomentosa alkaline hydrogen peroxide pulp (APMP). The changes of pulp brightness were measured and the effects of LMS on the subsequent hydrogen peroxide bleaching were also determined. Besides, the fiber morphology was analyzed by ESEM, and then the obvious changes of pulp have been recovered. In a word, the LMS has obvious effect on cellulose.
Fabrication Microstructure and Microwave Absorption of Fe3O4 Decorated with Hyperbranched Copper Phthalocyanines
Authors: Meng Fan Bin , Liu Xiao Bo
Published: January 2015

In this work, novel Fe3O4–hyperbranched copper phthalocyanines (Fe3O4–CuPc) nanostructures were fabricated via a simple solvent-thermal method, and the electromagnetic absorption property of the composites was investigated. The introduction of CuPc molecules were not only attached to the surface of Fe3O4in form of beads, but embedded in the interior of Fe3O4. Importantly, the Fe3O4–CuPc composites exhibit excellent microwave absorbability, compared with that of Fe3O4. The composites with a coating layer thickness of 4.0 mm exhibit a maximum absorption of –30.3 dB at 10.2 GHz and the bandwidth below −10.0 dB reaches up to 10.6 GHz (from 7.4 to 18.0 GHz range). The excellent microwave absorption properties are ascribed to the improved impedance matching. The as–prepared novel Fe3O4–CuPc composites are shown to be lightweight, strong absorption, and broad frequency bandwidth microwave absorbers.
Influence of Surfactant on Electrochemical Process for Zn-Electrodeposition
Authors: Huang Dao Bing , Tu Yuan Qiang , Cai Jie , Feng Guan Wen , Guo Xing Peng
Published: January 2015

The electrodeposition of zinc from acidic sulphate bath on steel substrate has been studied. The influence of sodium dodecylbenzenesulfonate (SDBS) as surfactant on the mechanism of the electrodeposition process has been investigated using potentiodynamic and cyclic voltammetry (CV) techniques. From the analysis of CV analysis, it is shown that in the surfactant free bath solution, hydrogen evolution occurs together with the zinc deposition. The presence of SDBS shifts the reduction potential of Zn2+ to more negative values, indicating that SDBS to some extent hinder the Zn electrodeposition.
Mo Behavior in Mn-Zn Ferrite at High Temperatures Part 2: Sinter Mechanism of Mo in Fe-Rich Mn-Zn Ferrites
Authors: Cai Ya Qiu , Zhao Xu , Lin Yang Yi , Zheng Fu Nan , Huang Jin Tao
Published: January 2015

Mo behavior in Fe-rich Mn-Zn ferrites during sintering process was studied by adding MoO3 or MnMoO4 as additive. The influences of the additive amounts and treatment temperatures on microstructure, density, porosity as well as magnetic properties were investigated. It is found that formation of MnMoO4 in the grain boundary plays an important role. Saturation flux density (Bs) at 373 K as high as about 513mT could be obtained when the equivalent Mo content is 133ppm. Based on the experimental results, a new hypothesis is proposed to explain why proper Mo addition is essential to obtain ferrites of good qualities.
Determination of o-Chlorobenzamalononitrile Nonivamide, and Dihydrocapsaicin in Aerosol Defense Sprays Using UPLC
Authors: Lei Xiao , Luo Ai Qin , Sun Zhen Bin , Yang Shu , Sun Li Quan
Published: January 2015

A rapid and sensitive ultra performance liquid chromatography (UPLC) method was developed to quantify the principle active components (o-chlorobenzamalononitrile, nonivamide, dihydrocapsaicin) in a variety of aerosol defense sparys obtained from independent distributors of the products. Chromatographic separation of the target ingredients was achieved using UPLC employing a reversed phase C18 column and a stepwise gradient of methanol and distilled water. Quantification of the analytes was achieved using ultraviolet detection at a wavelength of 229nm.The plot of concentration versus peak area was linear over the range of 1.0-100.0ug/ml with a correlation coefficient (r2)≥0.999 for each analyte. The accuracy of the assay ranged from 97% to 105% for all analytes and the quality control samples at 10, 50, 100ug/ml. The inter-assay and intra-assay precision of the method were achieved with a relative standard deviations lower than 3.6%. The results of the analysis demonstrate the degree of variability in the active ingredient content of the sprays.
Investigation of Water Separation from Water-in-Oil Emulsion Using Centrifugal Field and Gravity with CFD Method
Authors: Li Qing , Chen Jia Qing , Wang Kui Sheng
Published: January 2015

Numerical simulation has been carried out to investigate water separation from emulsion with new equipment designed by ourselves. Three rotate speed of 300r/min,1500r/min,3000r/min have been calculated using Reynolds stress model ,which is at the same water volume fraction, droplet diameter and other physical parameters .When the rotate speed increase, the velocity and pressure drop of fluid tends to increase. Due to the effect of centrifugal field, the water volume fraction of near the wall is larger than that of inner fluid. Because of the gravity, the water volume fraction of bottom is larger than that of upper.
Features of the Processing of AA2124 Aluminum Alloy Metal Matrix Composites Reinforced by Silicon Nitride Prepared by Powder Metallurgy Techniques
Authors: Bezerra Carlos Augusto , Araújo de Moura Alexandre Douglas , de Araújo Edval Gonçalves , dos Santos Maurílio José , de Araújo Filho Oscar Olimpio
Published: January 2015

Powder Metallurgy (PM) Techniques consists in a suitable technique to process composites materials. A specific PM technique of mechanical alloying developed to produce new materials in the solid state is a well known route to obtain aluminum alloys metal matrix composites. Aluminum alloys metal matrix composites allies the good properties of aluminum and its alloys but with poor mechanical properties and the reinforcement of ceramics phases which add better mechanical properties to these alloys. The research of this materials processing by PM techniques presented new materials with improved properties. In this work an AA2124 aluminum alloy was reforced by particulated silicon nitride a kind of ceramic phase. The powders were mixed and then processed by mechanical alloying in a SPEX vibratory type mill. Then the powders obtained were compacted and vacuum sintered. The sintered composites were characterized by means of Scanning Electron Microscopy (SEM) plus Energy Dispersive Spectroscopy (EDS) and Vickers hardness tests to evaluate the mechanical behavior.
Characterization of Composites Based on 316 Stainless Steel and Zirconia for Use as Functionally Graded Materials
Authors: Arantes Vera Lúcia , Grajales Agudelo Leonardo , di Lorenzo Pedro Luiz
Published: January 2015

Functionally graded materials (FGM) based on stainless steel and ceramic materials have inspired researchers to combine properties and features which are not present in conventional composites, and are considered to be an alternative in the production of motors parts, cutting tools and coatings for reactors. The addition of metal and ceramic in a graded structure allows the integration of distinct properties that combine advantages of metallic and ceramic materials. Ceramic components withstand high temperatures and present high corrosion resistance, while metallic ones provide higher mechanical resistance, in particular ultimate tensile strength and fracture toughness. In this work, composites with variable levels of 316 Stainless Steel and Ytria-stabilized Zirconia, were prepared and characterized, in order to determine the thermal behavior of each composition, aiming the optimization of sintering of pieces with chemical composition gradation.
Effect of Sintering Temperature on the Formation of Intermetallics in Al-Fe-B Nanocomposite
Authors: Abenojar J. , Martínez M.A. , Criado A.J. , Velasco F.
Published: January 2015

Mixing and sintering aluminium and 20% mechanically alloyed Fe/B nanoparticles provokes the formation of intermetallics in the aluminium matrix when following a powder metallurgy route. Materials were sintered in a wide range of temperatures (from 600 to 1100 oC). Previous studies have shown that these materials present neither important dimensional changes during sintering nor significant differences in mechanical properties. However, sintering temperature strongly affects corrosion resistance and hot rolling capability. Low sintering temperature provides nanocomposites with lower corrosion properties and hot rolling capability. In this work the nanocomposites obtained at different temperatures were characterized by X-ray diffraction. This technique allows following the formation of different intermetallics at each temperature, since being non-equilibrium processes, the use of ternary phase diagram of these elements is not possible.
Phase Transformation in Mechanically Alloyed and Hot-Pressed Nb-4Si-8B and Nb-8Si-16B Alloys
Authors: Chiaradia Carlos Edilson , Alkmin Luciano Braga , Nunes Carlos Ângelo , Henriques Vinícius André Rodrigues , Pereira Gilda Maria Cortez , Ramos Alfeu Saraiva
Published: January 2015

The work reports on the phase transformation in mechanically alloyed and hot-pressed Nb-4Si-8B and Nb-8Si-16B (at-%) alloys. Elemental powder mixtures were processed in a planetary ball mill under argon atmosphere using 300 rpm, stainless steel balls (19 mm diameter) and vials (225 mL), and a ball-to-powder weight ratio of 10:1. After dry milling for 7h, wet milling with isopropyl alcohol for more 20 min was adopted to increase the recovering of previously cold-welded Nb-4Si-8B powders. To obtain the equilibrium structures the as-milled powders were hot-pressed under vacuum at 1200oC for 1 h. The as-milled powders and hot-pressed samples were characterized by X-ray diffraction, scanning electron microscopy, and energy dispersive spectrometry. XRD results revealed the presence of metastable phases in as-milled Nb-Si-B powders. The hot pressing has produced dense Nb-Si-B samples, which were formed by the Nbss, Nb3B2 and Fe2Nb phases beside of other unknown Si-rich phase.
Fourier Transform Infrared Spectroscopic Study of Boron-Doped Micro/Nano/Ultrananocrystalline Diamond Prepared by Chemical Vapor Deposition
Authors: Arantes Tatiane M. , Santos Nazir M. , Azevedo Adriana F. , Baldan Mauricio R. , Ferreira Neidenei G.
Published: January 2015

Boron-doped diamond (BDD) films were grown with different grain sizes. The films were deposited on silicon substrate after a suitable pre-treatment in a hot filament assisted by chemical vapor deposition (CVD) reactor in Ar/H2/CH4 gas mixtures. The addition of argon to the growth gas mixture clearly revealed the transition from nanocrystalline (BDND) to ultrananocrystalline (BDUND) diamond films. Raman spectroscopy results of BDD, BDND and BDUND exhibited a good quality diamond films considering the diamond defined peak. Fourier Transform Infrared Spectroscopy (FTIR) spectra indicated carbonyl groups and B-C in BDND and BDUND films, while the microcrystalline BDD films showed only C-H bonds and boron-carbon (B-C), without the presence of oxygen and unsaturated species. Therefore, the carbonyl presence in the nanocrystalline films is mainly due to oxidation of transpolyacetylene present at the film grain boundaries. The transition became pronounced in the gas mixture with 60% of Ar, and the microcrystalline films were totally transformed in nanocrystalline diamond at 70% of Ar.
Micro, Nano and Ultranano-Crystalline Diamond Deposition
Authors: Barbosa Divani C. , Baldan M.R. , Trava-Airoldi V.J. , Corat Evaldo Jose
Published: January 2015

This is a comparative experimental study of the micro, nanoand ultranano-crystalline diamond deposition. The Hot Filament Chemical Vapor Deposition (HFCVD) reactor deposits the films using different deposition parameters. Scanning Electron Microscopy and Field Emission Scanning Electron Microscopy let morphology inspection. Visible-Raman scattering loaded to estimating relative induced stress, by the graphite peak shift and associated with the defect incorporation and sp2 bond enhancement. The x-ray diffraction confirmed the diamond crystallinity, where Scherrer ́s equations estimate crystallite size and diamond renucleation rates. In this work we propose a defect increasing relative graphite incorporation with the transition of micro, nanoto ultranano-crystalline diamond deposition. Besides this, we propose that this increase defects follows the increase diamond renucleation rates and decreases in the induced stress films. Included is a discussion of the possible reasons for these observations.
Electric Double Layer Capacitor of Multiwall Carbon Nanotubes under Different Degree of Acid Oxidations
Authors: Saito Eduardo , Caetano Vagner Eduardo , Antunes Erica Freire , Lobo Anderson Oliveira , Marciano Fernanda Roberto , Trava-Airoldi Vladimir Jesus , Corat Evaldo José
Published: January 2015

Carbon nanotubes (CNT) are a material with unique properties (mechanical, electrical, electrochemical, etc) allied with low density and high specific area. The present paper studied the electrochemical properties of carbon nanotubes growth by Chemical Vapor Depostion (CVD) technique. The samples were characterized by SEM, Raman Spectroscopy and the double layer capacitance of the powders was evaluated in a Teflon capacitor system with a Ag/AgCl (3M) as reference electrode. The catalyst remotion is provided in Hydrochloric acid washing and the wet oxidative treatments promotes the CNT oxidation and increase the pseudocapacitive response.
Project and Construction of a Differential Mobility Analyzer to Produce Monosized Nanoparticles
Authors: Dalcin Maurielem Guterres , Nunes Deivid Marques , Damasceno J.J.R. , Arouca F.O.
Published: January 2015

The nanotechnology has become an important area, either because the special features of nanometric particles confer to products, or due to a maximum limit of emission of such particles in air. However, the reduced size of this kind of particle limit them to be separated by conventional techniques, and a good way to ensure an aerosol stream with monodispersed particles is to use the electrical mobility technique. This theory is based on the ability of a charged particle to cross an electrical field, thus depending of the size of particles, the bigger ones will arrive later in the central electrode than the smaller ones, and only a narrow band of sizes will be collected in a slit located in the bottom of the equipment. This work aimed to project and construct a Differential Mobility Analyzer (DMA) in order to produce an aerosol containing NaCl nanoparticles monodispersed, from a aerosol polydispersed produced by an atomizer. The operating principle is to charge NaCl nanoparticles with a neutralizer so that they can be collected according to the voltage applied to the DMA in a specific range of size distribution. The unit comprises a compressor for generating air current, high efficiency filters in order to generate ultrapure air, atomizer, reservoir of NaCl solution to generate aerosol, a diffusion dryer to remove moisture silica current gas, a source of X-rays to charge nanoparticles, a source of high voltage to be applied to the DMA, a DMA to classify the nanoparticles and a particle counter to perform the counting of particles before and after DMA. Preliminary results indicated the dependence of the particle size with the applied electric field. The results were very promising.
A CFD Study of the Air Distribution at Non-Conventional Dryers Using Different Configurations of Mini Pipes
Authors: Silvério B.C. , Resende I.A. , Santos D.B. , Duarte C.R. , Barrozo M.A.S.
Published: January 2015

Rotary dryers are a significant capital item for many industrial plants. Many potential benefits can be obtained through a greater understanding of the rotary drying process. In order to improve drying efficacy, a novel version of the rotary dryer, known as the rotoaerated dryer, was evaluated in previous studies. This work has studied the effect of the configuration and arrangement of mini-pipes in the rotoaerated dryers by experimental and CFD techniques. The results obtained showed that it was possible to predict the effect of variations in the configuration of the rotoaerated dryer and obtain the more appropriate arrangement of mini-pipes.
Analysis of Solid Concentration Profiles in Batch Sedimentation Tests Using Viscous Newtonian Fluids
Authors: Moreira Bruno Arantes , Arouca Fábio de Oliveira , Damasceno João Jorge Ribeiro
Published: January 2015

The study of the sedimentation of particulate materials is of interest in several industrial processes, such as in the design and optimization of operating conditions of thickeners and during the operational stages of drilling oil wells. In this context, this work aims to study the sedimentation of particles in viscous Newtonian fluids. For the tests, aqueous solutions of glycerol were used in the volumetric concentration of 80% and 92%. The suspensions were prepared using sand with the size range of 150-212 μm. The settling of particles was studied by using a nondestructive technique based upon the measurement of gamma-ray attenuation for achieving the local concentration of solids. The results showed that the sedimentation velocity of particles was changed significantly with increasing fluid viscosity. Moreover, the dynamic behavior of the particles settling in both glycerol solutions showed similar, with two regions of varying concentration of solids very defined: one in which the solids concentration remained constant until the transition from descending clarified interface; and the other in which the concentration remained constant until the formation of sediment.
Evaluation of Self Cleaning System in Aerosol Filtration Using Synthetic Filter
Authors: Arouca A.M.M. , Gerkman G.C. , Arouca F.O. , Vieira L.G.M. , Damasceno J.J.R.
Published: January 2015

In industries that work with particulate material is observed from among other concerns, not to discard solid material in the air. Aiming to develop gas-solid filtration equipment more efficient, the study of a self-cleaning system utilizing filter fabric made ​​from synthetic material, was conducted using the phosphate rock as particulate material. The objective of this study is to evaluate the performance of a vibratory system filtration of gases. The system is made up a box filter coupled to an eccentric motor which causes a continuous vibration during the filtration cycle, not being necessary to interrupt the process to the procedure of fabric filter cleaning. We used polyester synthetic filter for the tests. With known relative humidity and temperature at which the tests were performed, it was possible to estimate the performance of the equipment in continuous vibration filtration of pulverulent material dispersed in gas currents, under the influence of different vibration frequencies.
Study of the Capacity in a Totally Permeable Hydrocyclone
Authors: Salvador Fernanda Falqueto , Silva Nathcha Kare Gonçalves , de Souza Barrozo Marcos Antonio , Vieira Luiz Gustavo Martins
Published: January 2015

Hydrocyclones are equipments that separate a discrete phase (solid, liquid or gas) from a continuous phase (liquid) by generating a centrifugal field. The objective of this work was to study, experimentally, the incorporation effect of cylindrical and conical permeable walls (CyCoFH) on an optimized geometry hydrocyclone (H11) to evaluate the equipment’s processing capacity. By inserting a filtering cone and cylinder, during the operation of these separators, besides the traditionally observed streams (underflow and overflow), there is an additional liquid stream resulting from the filtering process in the conical and cylindrical regions. Despite the low filtrate flow observed during this new equipment’s operation, it was found that the filtration is benefic to hydrocycloning. According to the main results, the CyCoFH hydrocyclone of lower permeability presented a greater processing capacity. The feed flow rate was 23% higher than the corresponding conventional hydrocyclone, in the same geometrical and operational conditions.
Experimental Study of the Hydrocyclone H11 with Rotational Feed
Authors: de Oliveira Silva Danylo , Salvador Fernanda Falqueto , Vieira Luiz Gustavo Martins , de Souza Barrozo Marcos Antonio
Published: January 2015

Hydrocyclones are separators that are widely used in industry that belong to an important group of equipments designed to solid-liquid or liquid-liquid separation. The employment of hydrocyclones is generally restricted to an equipment need with a high classifying power (based on the size of particles collected in the underflow) or with a high concentrating capacity. The separation occurs by density difference or particle size distribution of the dispersed phase. In order to maximize the separation efficiency of these devices, the aim of this work was to study experimentally the consequences of an unusual feed in the behavior of a hydrocyclone. Therefore, tests were carried out with aqueous suspensions of phosphate rock at a fixed level of pressure drop equal to 1.47 bar, using the optimized geometry hydrocyclone H11. The influence of the so called rotating feed inlet for the H11 was evaluated in clockwise and anticlockwise. Experimental studies have suggested that the rotation of the fluid in the feed inlet of hydrocyclone did not change significantly the underflow-to-throughput ratio (RL), although it has caused changes in the energy cost and in the performance of the separator.
Synthesis and Characterization of Barium Titanate by Solid-State Reaction
Authors: de Andrade Mônica C. , Carneiro Geysa N. , Moreira Elizabeth L. , Araújo Jorge C. , Moraes Valéria C.A.
Published: January 2015

Solid-state reactions were used to synthesize pure and doped barium titanate powder. Barium titanate formation with tetragonal perovskite structure was detected by X-ray diffraction and occurred at a temperature above 700°C for pure powder and 500°C for doped powder. However, quite crystalline samples were observed only at 800oC and 600°C for pure and doped barium titanate, respectively, what made the refinement of the synthesized powders possible. They were characterized by X-ray diffraction and Fourier transform infrared spectroscopy and scanning electron microscopy. X-ray diffraction data was analyzed by using the Fullprof Rietveld refinement approach, Thompson-Cox-Hastings pseudo-Voigt with function. The refinement method was effective in the study of the temperature influence on the microstructure of the analysis of pure and doped barium titanate.
Structural Evolution of Ti-Fe-Si-B Alloys Produced by High-Energy Ball Milling and Sintering
Authors: Pereira Wladimir Leite , Bertoli Isadora Rossi , de Aquino Franzé Juliana , Ramos Alfeu Saraiva , Mariano Neide Aparecida , Nunes Carlos Angelo , Trindade Ramos Erika Coaglia , Nunes Carlos Angelo
Published: January 2015

This proposal aims at structural characterization of Ti-Fe-Si-B alloys produced by high-energy ball milling and subsequent sintering. In this study, quaternary alloys were prepared from raw materials of high purity: Ti (99.9 wt-%), Fe (99.8 wt-%), Si (99.999 wt-%) and B (99.5 wt-%). The milling process of the Ti-2Fe-22Si-11B and Ti-7Fe-22Si-11B (at-%) powders was carried out in a planetary Fritsch P-5 ball mill. Subsequently, the Ti-Fe-Si-B powders milled for 600 min were sintered (1100 ° C for 240 min) under vacuum to obtain equilibrium structures. The characterization of as-milled powders and sintered alloys was performed by means of X-ray diffraction, scanning electron microscopy, and electron dispersive spectrometry. Extended solid solutions were formed during the initial milling times while that the brittle Ti5Si3 phase was formed for longer milling times in both the quaternary powder mixtures. This fact contributed for reducing the particle sizes. Homogeneous samples containing a small amount of pore were obtained after sintering at 1100°C for 4h. Results have indicated that the iron addition favored the formation of different binary phases of the Ti-Si system, and the formation of the Ti6Si2B compound was inhibited from the Ti-Fe-Si-B powder mixtures.
Densification Behaviour Modelling for Metallic Powders
Authors: dos Santos Freitas Maria Carolina , de Castro José Adilson , Moreira Luciano Pessanha , Vitoretti Flávia de Paula
Published: January 2015

Powder forming involves fabrication of a preform by conventional press-and-sinter processing, followed by various forming processes, citing as examples, rolling, compaction, forging, extrusion, among others, of the porous preform into a final shape through substantial densification. This work makes a finite element analysis for porous metals. The finite element model was applied to simulating the case of compaction of nanocristalline copper under uniaxial compression conditions in order investigate the densification behavior. The model was simulated using explicit integration method as applied to the evolution variation of the relative density and the dislocation density of the compact. Finite element analysis program used was Abaqus. Finite element calculations were compared with literature data. The agreements between finite element model and literature results for densification of nanocristalline copper were good.
Atomization and Selective Laser Melting of a Cu-Al-Ni-Mn Shape Memory Alloy
Authors: Mazzer E.M. , Kiminami Claudio Shyinti , Gargarella P. , Cava R.D. , Basilio L.A. , Bolfarini C. , Botta W.J. , Eckert J. , Gustmann T. , Pauly S.
Published: January 2015

Shape memory alloys (SMAs) are a class of material that undergoes a reversible shape change after a plastic deformation. The recovery of the original shape is possible due to a structural transformation upon heating to a critical temperature. The shape memory effect is related to a martensitic-austenitic transformation from a phase with a low symmetry (martensite) to a high-temperature phase (parent phase) [1]. Cu-based shape memory alloys have the advantage of large thermal and electrical conductivities and the system Cu-Al-Ni alloys are quite attractive due to better stabilisation against aging phenomena [2].
Mechanical Characterization of a Steel AISI 43100 Submitted to Different Routes of Heat Treatments
Authors: Frade Drumond Ana Lídia , Abdalla Antonio Jorge , de Moura Neto Carlos , Manabu Hashimoto Tomaz , de Oliveira Hein Luis Rogerio
Published: January 2015

The present study aimed to explore possible thermal processing conditions of a steel AISI 43100, seeking the best combination of properties, especially strength and ductility. Different routes of heat treatments for continuous cooling were applied to the material, and the mechanical properties were evaluated by tensile and hardness tests. The microstructure and fracture micromechanisms were characterized by scanning electron microscopy (SEM). It was observed a strong influence of cooling rate on the formation of microstructure, reflecting directly in mechanical properties.
Effects of Sodium Nitrite, Sodium Dichromate and Benzoic Acid as Inhibitors in the Protection of Mild Steel in Water
Authors: de Jesus Silva José Wilson , Belo A.P.O. , Ribeiro R.B. , Matias N.T.
Published: January 2015

In Petrobrás SA refineries, there are thousands of heat exchangers in which cooling water is treated for recycling, often by outsourced companies. In all of these refineries there happens shutdown for corrective maintenance of the exchangers by problems related to corrosion caused by the cooling water, requiring about four days to repair a unit. The shutdown of a production line results in loss of revenue between U$ 200,000.00 and U$ 300,000.00 per day. To control the cooling water quality, it is used coupons for corrosion analysis. Tests are limited to visual inspection and by mass loss analysis. In this work, inhibitors such as sodium nitrite, sodium dichromate and benzoic acid are used to protect metals immersed in water in order to avoid the corrosion and consequently the shutdown of the exchanger for corrective maintenance.
A Comparative Study of Biomimetic Coatings on Titanium and Stainless Steel
Authors: Coelho Mariny Fabiéle Cabral , Cronemberger Maria E.R. , Pereira Juliete N. , Nakamatsu Sandra , Maestrelli Sylma Carvalho , da S. Rigo Eliana C. , Mariano Neide A.
Published: January 2015

Titanium and stainless steel are examples of biomaterials widely used in dental and orthopedic implants owing to their properties of good corrosion resistance and excellent biocompatibility. This paper reports on a study of the biomimetic method applied to titanium (cp-Ti) and 316L stainless steel. The method consists in immersing the metal substrate in a synthetic solution of SBF (simulated body fluid) whose composition, pH and temperature resemble those of human blood plasma. The coating on the two metals was effective for obtaining hydroxyapatite, which was confirmed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR).
Characterization of Porous Ti-35Nb Alloy Sintered at Different Temperatures for Implant Applications
Authors: de Oliveira Cristyane Silva Santos , Antunes Ribeiro Alexandre , Ribeiro Alexandre Antunes , Balestra Roseli Marins , Griza Sandro , de Oliveira Marize Varella
Published: January 2015

Studies show that porous titanium alloys improve osseointegration at the implant-bone interface, since they induce new bone tissue formation inside the pores providing a better mechanical stability. In this work, porous Ti-35Nb samples were manufactured by powder metallurgy for orthopedic implant application. The titanium and niobium powders were mixing with a pore former additive and then uniaxially and cold-isostatically compacted. The samples sintering were performed at 1200oC and 1300oC. Samples characterization was performed by Scanning Electron Microscopy with Energy Dispersive X-Ray (SEM/EDS), X-Ray Diffractometry (XRD) and Optical Microscopy (OM). Moreover, ultrasound test and Quantitative Analysis by Optical Metallography (QAOM) were conducted to obtain the modulus of elasticity and total porosity, respectively. The results indicated that the used processing parameters made it possible to obtain homogeneous microstructures throughout the length of the sample.
Influence of the Grain Size on the Dysprosium Diffusion in NdFeB Magnets
Authors: de Castro José Adilson , de Campos Marcos Flavio
Published: January 2015

The dysprosium-diffused Nd2Fe14B magnets are a feasible way to increase coercivity and saving dysprosium at the same time. In the practice, a dysprosium source layer is placed over a NdFeB magnet substrate, and Dy diffusion takes place from the surface to the center of the substrate. This practical situation is modeled in the present study. The main microstructural variables are the grain size of the magnets and the volume fraction of the intergranular phase (Nd-rich), the modeling temperature of 900°C. It is found that this process may have increased kinetics if the grain is reduced or if the volume fraction of the intergranular phase is increased.
Frequency Characterization of Ferrite Beads in the Microwave Range for Nonlinear Applications
Authors: Silva Neto Lauro Paulo , Rossi J.O. , Dias P.A.G. , Barroso J.J.
Published: January 2015

Ferrite beads are ferromagnetic materials that exhibit a small inductance at low frequencies, becoming resistive at high frequencies. These devices are used as low pass filters for reducing electromagnetic interference (EMI) in communications and power electronics because the resistive losses attenuate the undesired frequencies. As ferrite beads have a nonlinear behavior with current and frequency they have been used in nonlinear transmission lines (NLTLs) for high power microwave generation in space and defense applications. In this work, high frequency ferrite beads are characterized in the frequency range up to 1 GHz by measuring S11 reflection parameter in order to calculate their complex permeability and losses, key parameters in the design of NLTLs. In addition, X-ray diffraction (XRD) is used to identify their chemical element composition. Finally, the motivation for this work is basically due to the limited information on ferrite materials provided by the manufacturers.
Magnetic Domains Observation from Bitter Patterns of NdFeB Alloy
Authors: Lemos Raphael , de Souza Kaio Sérgio T. , da Silva Fernanda A. Sampaio , Rodrigues Daniel , de Castro José Adilson , de Campos Marcos Flavio
Published: January 2015

The Bitter method is an adequate method for domains observation, and depends on careful metallographic preparation and also on a proper magnetic colloid solution. In this study, Bitter patterns were obtained for a Nd-Fe-B as-cast alloy. The Nd2Fe14B grains show strong anisotropy during growing, and are larger for the direction perpendicular to the easy magnetization axis. The equilibrium distance between domain walls allows an estimate of intrinsic parameters of ferromagnetic phases as the domain wall energy and the single domain particle size.
Feasibility Study for Feedstock Recycling on PIM Nd-Fe-B Permanent Magnets
Authors: Lopes Leonardo Ulian , de Souza Lia Fook Pablo Vinicius , Owczarzak Andres , Uenal Nil , Hartwig Thomas , Wendhausen Paulo Antônio Pereira
Published: January 2015

Powder injection molding (PIM) is a well-known process for the production of geometrically complex shaped parts at a high production rate. The possibility of recycling the raw material (feedstock) is economically necessary for industrial applications, especially when processing very expensive materials, such as rare-earth alloys. In this study, Nd-Fe-B magnets were fabricated by powder injection molding, in which the injection residues (gates, sprue and surplus green samples) were reprocessed, up to 6 times. Subsequently, samples underwent binder extraction by chemical and thermal procedures, being finally sintered under high vacuum. Physical characterizations were carried out and the magnetic properties were measured via B-H trace analysis in each batch to study the influence of the recycled feedstock on the magnetic properties of produced samples. It was concluded that the properties are significantly affected after the second reprocessing lot, mainly due to the contamination of the feedstock by organic elements by-products of the binder decomposition.