bluuebunny/crossref_metadata_2025 huggingface dataset:
One Step Fabrication of Core-Shell Structures in Immiscible Alloys for Thermal Energy Storage
Authors: Xu Fu Min , Fu Ming Bi , Dong Wei , Zhao Li , Lu Dong , Tan Yi
Published: June 2014

The microscopic morphologies of Bi30Ga70immiscible alloy particles were investigated. Monosized microparticles with similar core-shell structures were fabricated for the first time by one step using the Pulsated Orifice Ejection Method. The EDS revels that the core and the shell consist of a Ga-rich phase (＞90 at. %) and a Bi-rich phase (＞80 at. %), respectively. The DSC testing at different temperatures is performed. Core-shell microstructures as well as endothermic peaks and exothermic peaks are observed after heating-cooling cycles when the working temperature is below the temperature of spinodal line, indicating good thermal stability after phase transformation. The thermal energy storage was preliminary tested, which is a good attempt for thermal energy storage. It is likely to use core-shell structures as microencapsulated phase change materials.
The Structure and Properties of NBR / Recycled Polytetrafluoroethylene (R-PTFE) Composites
Authors: Chen Wen Wen , Cao Chang Lin , Zhang Yi , Xiao Li Ren , Qian Qing Rong , Chen Qing Hua
Published: June 2014

The structure and properties of NBR and its composites coupled with different particle size of recycled polytetrafluoetylene (R-PTFE) are investigated. The results show that R-PTFE has a positive effect on NBR enhancing the curing properties of materials, mechanical properties, solvent resistance of NBR when the particle size of R-PTFE less than 200 mesh. However, when it is 200 mesh, R-PTFE is not easily dispersed in the NBR matrix, resulting in decreasing the properties of NBR/R-PTFE composites.
Microstructure and Direct Measured Micro-Strain by TEM of Hot Iso-Static Pressed Alumina-Titanium Carbide (Al2O3-TiC) Composite
Authors: Thumsoontorn Sineenart , Kuimalee Surasak , Kuntalue Budsabong , Pintasiri Suphakit , Lohwongwatana Boonrat
Published: June 2014

Alumina-titanium carbide composite (Al2O3-TiC) is one of advance ceramic matrix composites (CMC) that have been used in machining tool and tribology application because of its excellent mechanical properties. Powder processing is often a chosen method to produce this family of material, i.e. hot pressed (HP), hot iso-static pressed (HIP), and pressure-less sintering (PS). These manufacturing techniques convert sub-micron powder into dense bulk component. Al2O3-TiC composite has been prepared by HIP process, containing 65%vol Al2O3and 35%vol TiC. The powders were pressured and sintered at temperature between 1250˚C - 1650˚C. Thermal residual stress from Al2O3-TiC manufacturing process is conventionally unavoidable. The aim of this study is to investigate the microstructure of HIPped Al2O3-TiC composite and its residual micro-strain using transmission electron microscopy (TEM) with selected area electron diffraction pattern (SADP) analysis. The Al2O3-TiC composite was prepared by high-precision machining/grinding processes then focus ion beam milling process was used to section the TEM lamella. Microstructures, grain size and phases were determined by TEM and X-ray diffractometry (XRD). Micro-strains of {200}TiC, {111}TiC , {220}TiC and {012}Al2O3were investigated by SADP (Selected Area Diffraction Pattern). Our result revealed there is approximately 0.01 compressive strains distributed in Al2O3-TiC composite.
The Research Process and Application Prospect of the Smart Piezoelectric Materials
Authors: Fang Xiao Liang , Zhang Wei Fang , Wang Hong Xun
Published: June 2014

Piezoelectric material which can be used as both sensor and drive is an important kind of smart material. Studies on piezoelectric materials are now the research focus and hotspots of smart materials which have achieved fruitful results. This article describes the working principle of smart piezoelectric materials, provides an overview of the preparation progresses and application status, based on which the research and development trends are discussed.
The Research of Demarcating the Laser Ranging Sensor by Least Squares Method
Authors: Zheng Yan , Zhang Yong , Fan Xiao Wang
Published: June 2014

Basing on the laser range finder needs calibration used in non-contact measurement the, using the triangle range principle, through the experiment of design of different material, surface roughness, the under the different distance of under the different distance between 40 mm to 60 mm is achieved, the under the different distance, demarcated the laser ranging sensor by least squares method and analyzed the pricesion.
Design Study of Small Gas Cooled Fast Nuclear Power Plant for Synergetic Energy System with Renewable Energy by Employing Pump Storage
Authors: Suud Zaki
Published: June 2014

Design study of a synergetic system among small long life gas cooled fast reactors and renewable energy has been performed. A pump storage system is the center in the integration among considered energy sources. Using this system many renewable energy sources and the small nuclear power plant can be integrated to produce reliable energy sources which can be used for electricity production, desalination, etc. In this system each energy source can store energy by contributing pumping water from a low level reservoir to a high level reservoir. The nuclear power plant module must satisfy inherent safety requirement, and have flexibility in producing electricity, clean water (through desalination), etc. The reactor can be operated for 25 years without the necessity to refuel during that period. To achieve inherent safety capability it is important to minimized excess reactivity during burn-up to be below delayed neutron fraction value so that super prompt critical accident such as in Chernobyl accident case can be avoided. Here minimization of excess reactivity is carried out by adjusting core and blanket region width and plutonium enrichment in core regions.
Electrochemical Performance of LiFePO4/C Prepared from Different Carbon Source
Authors: Liu Ai Fang
Published: June 2014

Cathode material LiFePO4/C was prepared via optimized solid state reaction and calcinations using different carbon source. The crystalline and morphology of the resultant powder was evaluated by X-Ray diffraction (XRD), scanning electronic microscope (SEM). The electrochemical performance was measured by galvanostatic charge-discharge test at 0.1C and 0.5C. The results demonstrated that the sample with layer-like stacking microstructure had the best capacity retention up to 96% after 50-cycle at 0.5C; the sample with good carbon coating using glucose as carbon source exhibited the lowest flat charge plateau and the highest flat discharge plateau, also the best storage performance at 60 oC temperature. Nevertheless, the sample with spherical-like shape and homogeneous particle size had the most capacity loss, maybe due to the increased internal resistance caused by the big interstices between the particle sizes.
Measurement Principle of Glass Thermal Expansion Coefficient and Technology Application of DIL402PC Dilatometer
Authors: Sun Yan Hua , Zhang Dong Qing , Wu Fei , Sun Kai
Published: June 2014

The paper introduces the measuring principle of glass thermal expansion coefficient. It expresses the features and advantages of the linear variable differential transformer measuring principle by comparing the thermal expansion coefficient measurement methods analysis. Meanwhile, the paper introduces DIL402PC dilatometer measuring devices and measurement procedures. It use standard samples to execute thermal expansion instrument system check from the accuracy and repeatability. The result shows thermal expansion coefficient of linear expansion instrument bias of DIL402PC dilatometer is within the error range of the theoretical value. The process proves it has a wide range of applications.
An Exploration of Factors Affecting the Preparation of SiO2-Coated α-Al2O3 Pearlescent Pigment
Authors: Wu Nan , Chen Qing Hua , Zhou Wei Ming , Ke Mei Zhen , Qian Qing Rong , Yuan Zhan Hui
Published: June 2014

The SiO2-coated α-Al2O3 pearlescent pigment was prepared by liquid phase deposition (LPD). The effects of concentration of sodium silicate solution, reaction temperature and pH value of the aluminum oxide suspending liquid were systemically studied in this paper. The obtained samples were characterized by scanning electron microscopy (SEM). The results showed that when the process parameters are the concentration of sodium silicate solution of 0.1 mol/L, the reaction temperature of 80 °C and the pH value of 9.0, the high quality of SiO2-coated α-Al2O3 pearlescent pigment could be obtained.
Solar Hydrogen Production Research Status and Prospect
Authors: Wang De Zhi , Zhao Fu Zhou , Zhu Cai Li
Published: June 2014

The status of solar hydrogen production, solar hydrogen production from water electrolysis, solar photochemical hydrogen production, biological hydrogen production, solar thermal decomposition of water hydrogen production and other hydrogen production methods are presented in this paper. Then the key technologies of various hydrogen production are investigated in detail. Analysing the domestic and foreign research progress, the state-of-the art solar hydrogen production can be got to know in this paper. On the basis of solar hydrogen production, some prospects are put forward.
The Effects of the Total Number of Regions and Average Power Density on the Overall Performance of Modified CANDLE Burn-Up Scheme Based Gas Cooled Fast Reactors
Authors: Rosidah Indah , Afifah Maryam , Suud Zaki , Sekimoto Hiroshi , Ferhat A.
Published: June 2014

In this study the effects of the total number of regions and average power density in Modified CANDLE burn-up scheme are studied. In the previous studies usually 10 equal axial regions are applied in Modified CANDLE burn-up scheme, and in this study 6, 8 and 10 regions Modified CANDLE burn-up scheme performance is compared and discussed. The core power level varied from 800-1000MWt. Several comparisons are performed between 10 and 8 regions Modified CANDLE, 8 and 6 regions Modified CANDLE and some additional comparison which include some changing in power level. Some general remark which we can get from this study is that reducing region with the same cycle length and power level will resulted in significant drop of effective multiplication constant especially at the beginning of life and the reduction of discharge burn-up level. On the other hand the increase of the power level with the same region number and cycle length resulted in higher effective multiplication constant value especially at the beginning of life, while at the end of life the differences are decrease. Then when we reduce the region number and increase the power level at the same time we get the mixed effect in which the system performance is relatively go back to the original case.
A Proposed Method of Photovoltaic Solar Array Configuration under Different Partial Shadow Conditions
Authors: Humada Ali Mahmood , Hojabri Mojgan , Mohamed Mortaza B. , Bin Sulaiman Mohd Herwan , Dakheel Taha Hamad
Published: June 2014

The benefit of improving the efficiency of photovoltaic (PV) solar system has come into view because of increasing the demand for electricity, especially in the urban areas. However, these PV solar systems are vulnerable to the mismatch operating conditions. Under such conditions, the performance of solar cells has decreased rapidly since the nonuniform insolation hitting the cells and with different values. Then this leads to cause rapidly decreasing in the output power value and maximum power point, beside to hot spot points that may be occurring in the solar cell which finally leads to damage these cells. This paper proposes an optimal connection of substrings with different value of shadow conditions, based on a thorough configuration that can significantly reduce that nonuniform condition loss. The refinement over existing photovoltaic (PV) solar array interconnections is proven by extensive simulation results by using MATLAB SIMULINK.
Numerical Simulation of NOx Emission in Supercharged Boiler
Authors: Zhang Hong Yan , Zhao Jing , Yang Long Bin , Li Yan Jun
Published: June 2014

The actual supercharged boiler is reasonably simplified and the geometric model of the furnace and the mathematical model of steady-state three-dimensional turbulent reaction are built in this paper. Numerical simulation of the thermal NOx emission under three different loads in the furnace of a supercharged boiler is conducted with FLUENT software. The thermal NOx emission increases in the furnace when the load increases and the largest mole fraction of the thermal NOx mainly exists at the back edge of high temperature.
Conceptual Design Study of Small 400 MWt Pb-Bi Cooled Modified Candle Burn-Up Based Long Life Fast Reactors
Authors: Suud Zaki , Sekimoto H.
Published: June 2014

In this paper conceptual design study of modified CANDLE burn-up scheme based 400 MWt small long life Pb-Bi Cooled Fast Reactors with natural Uranium as Fuel Cycle Input has been performed. In this study the reactor cores are subdivided into 10 parts with equal volume in the axial directions. The natural uranium is initially put in region 1, after one cycle of 10 years of burn-up it is shifted to region 2 and the region 1 is filled by fresh natural uranium fuel. This concept is basically applied to all regions, i.e. shifted the core of I’th region into I+1 region after the end of 10 years burn-up cycle. For small reactor core, it is important to apply high breeding material, so that high volume fraction of 60% fuel volume fraction nitride fuel is applied. The effective multiplication factor initially at 1.005 but then continuously increases during 10 years of burn-up. The peak power density initially about 307 W/cc but then continuously decreases to 268 at the end of 10 years burn-up cycle. Infinite multiplication factor pattern change, conversion ratio pattern change, and Pu-239 accumulation pattern change shows strong acceleration of plutonium production in the first region which is located near the 10th region. Maximum discharged burn-up is 31.2% HM.
Design Optimization and Control Analysis of Mechanical Arm Equipped on Wheelchair
Authors: Luo Gui Bin , Zeng Can Can , Zhu Li Da
Published: June 2014

Aiming at the phenomenon that our country has a large number of disabled due to illness or accident while the corresponding assistive devices is extremely deficient, we have designed a kind of mechanical arm which is intended to be equipped on wheelchair. We adopt articulated mechanical arm with multi-DOF as its mechanical structure, and choose MCU as the main controller; therefore it can make all kinds of flexible action to achieve a variety of functions. In order to improve the accuracy of manipulator, based on experimental results, we optimize the mechanical arm’s structure, improving its strength and stiffness; in order to realize the motion control of the manipulator, the kinematics analysis is conducted, when solving the mechanical arm’s anthropomorphic action problem, we set key points and then optimize the trajectory with linear interpolation, at last achieve anthropomorphic movement.
Comparative Study of Physico-Chemical Properties of Pure Polyurethane and Polyurethane Based on Castor Oil
Authors: Alaa M. A. , Yusoh Kamal , Hasany S.F.
Published: June 2014

Petroleum based polyurethanes are contributing major portions in the world requirement. To overcome the environmental issues and price adaptability, there is always a massive demand of utilization of renewable resources for polyurethane synthesis with comparable physico-chemical properties. Castor oil is the only major natural vegetable oil that contains a hydroxyl group (-OH) and unsaturated double bonds (C=C) in its organic chain and therefore can be employed with or without modification due to the excellent properties derived from the hydrophobic nature of triglycerides. In this study, physico-chemical properties of high performance polyurethane synthesized from Poly propylene glycol (PPG) in comparison with a combination of PPG and Castor oil (a renewable source), by in situ polymerization technique has been studied. The variations in properties of both types of polyurethanes are evaluated by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Thermogravimetric analysis technique (TGA). Tensile strength properties were investigated by Film Tensile testing equipment. Results indicated the presence of large-CH stretching in castor oil mixed polyurethane with a larger oxidative thermal stability, over a pure PPG polyurethanes. Tensile properties were found almost comparable in pure and mixed polymers, which signify the usage of mixed polymer in coming future, to overcome the environmental and economical crisis in polyurethanes synthesis.
Study on the Nanoemulsion Formulation of Piceatannol and In Vitro Release
Authors: Zhang Yue , Yu Yi Feng , Shang Zhen Hua , Du Man , Wang Chun Fang
Published: June 2014

In this paper, a novel stable piceatannol nanoemulsion is established. The piceatannol nanoemulsion formulation was screened based on the pseudo ternary phase diagrams. An optimized prescription was given as piceatannol 0.54%, EL-40 25.6%, ethanol 3.87%, castor oil 10.30%, water 60.23% (mass ratio), with the mean particle size 87.3 nm. The morphology of piceatannol nanoemulsion was characterized by TEM. The test results demonstrate that the nanoemulsion has dramatically improved the the solubility and release performance of piceatannol in ABS and PBS.
Using CO2 Emissions as a Maintenance Ratio in Manufacturing Processes
Authors: Calvo Luis Miguel , Domingo Rosario
Published: June 2014

Maintenance operations are particular important in continuous systems and even more so when they apply to the part considered the system’s bottleneck. Although complex support systems that help in decision-making decision therefore tend to be used, in industrial plants use of a simple indicator can facilitate management and help improve results. Concern for the environment and environmental legislation is meanwhile prompting a need to reduce CO2 emissions. Hence, the proposal for the introduction of the CO2 emissions/Production indicator. This paper will therefore both evaluate whether it is suitable as an indicator of system efficiency, with consideration for availability, stoppage time, average stoppage time and the duration of micro-stops, and also consider the ratio between monthly emissions and emissions on days with stops.
Labor Productivity in Projects of Construction and Industrial Maintenance
Authors: Loera-Hernández Imelda , Espinosa-Garza Gerardo
Published: June 2014

This paper is an accomplished investigation in a main industrial group of the city of Altamira, México, as part of a program of improvement of the labor productivity in the area of construction and maintenance of Aguila Industrial Group. The research focuses on the development of a methodology to assess the labor productivity of the industrial maintenance projects. In the methodology, we propose the use of a work sampling tool in order to identify the main factors that affect labor productivity as well as we proposes apply lean manufacturing tools to improvement labor productivity. In the paper, we discuss the implementation findings of the developed methodology as well as the preliminary outcomes of the main factors affecting labor productivity in the construction and maintenance industry; such outcomes provide a guide in the labor productivity management in one of the sectors that exhibits less development grade in most of the Latin-American countries.
A Comparative of 3D Surface Extraction Methods for Potential Metrology Applications
Authors: Ontiveros-Zepeda Sinué , Yagüe-Fabra José Antonio , Jiménez Pacheco Roberto , Brosed-Dueso Francisco Javier
Published: June 2014

The number of factors influencing the CT process for metrology applications increases its complexity and cause the loss of accuracy during CT measurements. One of the most critical is the edge detection also called surface extraction or image segmentation, which is the process of surface formation from the CT`s volume data. This paper presents different edge detection methods commonly used in areas like machine and computer vision and they are analyzed as an alternative to the commonly and commercially used for CT metrology applications. Each method is described and analyzed separately in order to highlight its advantages and disadvantages from a metrological point of view. An experimental comparative between two of them is also shown.
A Survey of Surface Texture Characterization with Two and Three-Dimensional Contact Methods
Authors: Calvo Felix , Sanz Alfredo , Negre Adrian A. , Fernandez Roberto
Published: June 2014

Nowadays there is a huge interest in new and improved three-dimensional techniques of surface finishing degree measuring and behaviour investigation. Several fields of application are mainly dependent of advances in surface metrology, as for instance aerospace and rail transport, telecommunications or micro-technology. All 3D measuring tools must be designed starting from a bi-dimensional basis and keeping a clear knowledge of their operating principle. This is then the key that defines the borders of this works path. Looking at the finishing degree of three differently obtained surfaces, preliminary comparison of results in two and three dimensions will be finally presented. All constraints defined by this problems conditions must be taken in consideration once the results are analysed.
Accuracy and Reliability Control of Machining Operations on Machining Centres
Authors: Dimitrov D. , Karachorova Viktoria , Szecsi Tamas
Published: June 2014

During machining operations on machining centres, there are a large number of internal and external factors that act on the technological system. They generate errors that influence the manufacturing cost, productivity, and machining accuracy. The monitoring and control system developed for machining centres presented in this paper consists of 3D touch probes, a device for registering a contact between the cutting tool and workpiece, devices for measuring the geometric accuracy of the machine tool and for calibrating the touch probe in the spindle, parameterised CNC programmes, computer and software for data processing and database management. The developed system guarantees monitoring of the machining accuracy, low cost, high level of productivity, low number of preparatory work and measurements, increased reliability due to reduced scrap rate by reducing the probability of cutting tool breakage, the possibility of automating the measurements and processing the data, and wide applicability.
Homing Sensor System Design for a 2D Long Range Nanopositioning Moving Platform
Authors: Acero Cacho Raquel , Albajez Jose Antonio , Yagüe-Fabra José Antonio , Torralba Marta , Valenzuela Margarita , Aguilar Martín Juan Jose
Published: June 2014

The nanotechnology field has been developing strongly in recent years and ultra-precision measuring systems are nowadays required. A new two-dimensional moving platform with 50x50 mm range of travel, nanometer resolution and sub micrometer accuracy is being designed by the authors in order to be integrated with an Atomic Force Microscope (AFM). In this work the definition, design and experimental characterization of a homing sensor system for this 2D moving platform is presented. The homing sensor system will allow the generation of an absolute 2D reference for the platform (X-Y axis and θz rotation), defining an initial cero for the measuring system, which is based on laser encoders.
Laser Tracker Error Modeling and Kinematic Calibration Strategy
Authors: Conte Javier , Santolaria Jorge , Majarena Ana Cristina , Brau Agustin , Aguilar Martín Juan Jose
Published: June 2014

Calibration of Laser Tracker systems is based most times in the determination of its geometrical errors. Some standards as the ASME B89.4.19 [1] and the VDI 2617-10 [2] describe different tests to calculate the geometric misalignments that cause systematic errors in Laser Tracker measurements. These errors are caused not only because of geometrical misalignments and other sources of error must also be taken in count. In this work we want to state the errors in a kinematic form. Errors will be split in two different components, geometric and kinematic errors. The first ones depend on the offsets, tilts and eccentricity of the mechanical and optical components of the system. Kinematic errors are different for every position of the Laser tracker, so they will be formulated as functions of three system variables: distance (R), vertical angle (V) and horizontal angle (H) usually called d, φ and θ. The goal of this work is to set up an evaluation procedure to determine geometric and kinematic errors of Laser Trackers.
Finite Element Model Correlation of an Investment Casting Process
Authors: Anglada Eva , Meléndez Antton , Maestro Laura , Domínguez Ignacio
Published: June 2014

The achievement of reliable simulations, in the case of complex processes as is the investment casting, is not a trivial task. Their accuracy is significantly related with the knowledge of the material properties and boundary conditions involved, but the estimation of these values usually is highly complex. One helpful option to try to avoid these difficulties is the use of inverse modelling techniques, where experimental temperature measurements are used as base to correlate the simulation models. The research presented hereafter corresponds to the correlation of a finite element model of the investment casting process of two nickel base superalloys, Hastelloy X and Inconel 718. The simulation model has been developed in a commercial software focused specifically on metal casting simulation. The experimental measurements used as base for the adjustment, have been performed at industrial facilities. The methodology employed combines the use of an automatic tool for model correlation with the manual adjustment guided by the researchers. Results obtained present a good agreement between simulation and experimental measurements, according to the industrial necessities. The model obtained is valid for the two studied cases with the only difference of the alloy material properties. The values obtained for the adjusted parameters in both cases are reasonable compared with bibliographic values. These two circumstances suggest that the obtained correlation is appropriate and no overfitting problems exist on it.
Technical Evaluation of Structural Adhesive Joints under Adverse Operation Conditions
Authors: Reina José M. Arenas , López Rosa Ocaña , García Cristina Alía , Prieto Julián J. Narbón
Published: June 2014

This work analyzes the degradation of aluminum-composite adhesive joints under the action of water and motor oil. For this purpose, we have performed an accelerated ageing of the adhesive joint by immersion in water and oil. Likewise, we have evaluated the loss of mechanical properties that aging causes into adhesive joint. First, tests have been performed with bulk adhesive specimens (epoxy and polyurethane) immersed in water and motor oil during independent periods of time (1 at 128 days) in order to study the diffusion of water and motor oil into the adhesive. Second, we have evaluated the loss of mechanical properties that aging causes in the adhesive joint. Tests conclusions show that water degrades the adhesive more than motor oil. Additionally and under the action of water and motor oil, polyurethane adhesive joints retain their mechanical properties better than epoxy adhesive joints.
Influence on Manufactured Products Design of the Processes of Project Management
Authors: de Mera Sánchez Prado Díaz , Gaya Cristina González , Rosales Prieto Víctor Francisco , Morales Camprubí Felipe
Published: June 2014

A key factor to enhance industrial competitiveness is to develop strategies around product design, applying the concept of excellence in all its stages and emphasizing innovation efforts. The process of product design as an important element in the differentiation between competing products needs to lean on effective tools that help to meet the demands of customers in the global competitive markets. In response to this need it arises, the European regulatory paradigm on the design of products, standard BS 7000-2: 2008 [1]. It is worth analyzing the influence on the design of manufactured products of the processes of project management of predictive models used mainly. The processes described in each of the models covered along with those reflected in the aforementioned regulations will provide guidance on any differences or similarities in the various phases at project level.
Real Time Diagnosis Charts of Thread Quality in Tapping Operations
Authors: Gil del Val Alain , Fernández Justino , Diéguez Pedro María , Arizmendi Miguel , Veiga Fernando
Published: June 2014

Tapping by cutting is one of the most common operations in manufacturing. It consists of cutting internal threads on the wall of a previously drilled hole by means of a tool called a tap that has cutting edges on its chamfered periphery. When tap wear is slight the process and geometry are usually in control and correct, respectively. However, when tap wear level is high the geometry is not correct and the process is out of control. This is an unacceptable industrial cost. The aim of this paper consists on an industrial monitoring application to data coming from the current/torque signal of the tap spindle for assessing thread quality. It operates in real time and indicates when the tap wear is so critical that, if the process were continued, it would result in unacceptable screw threads. Then the system shows a red light so that the operator could replace the worn-out tap. The system would be very cost-effective since the tapping process could be run without any operator intervention.
Topography Prediction on Grinding of Emerging Aeronautical TiAl Intermetallic Alloys
Authors: Beranoagirre A. , López de Lacalle Luis Norberto
Published: June 2014

Gamma-TiAl intermetallic materials are the focus of all leading aerospace / gas turbine manufacturers, as a replacement for some nickel-based superalloy components in parts of the engine subject to temperatures < 900°C. Although applicable for only a relatively narrow range of applications, titanium intermetallic materials are likely to play a significant role in the production of future aeroengines. This work presents the results from grinding tests on two types of Gamma TiAl alloys.
Influence of Standard ISO 21500 in the Management of Collaborative Networks
Authors: Otero-Mateo Manuel , Pastor-Fernandez Andres , Portela-Nuñez Jose M.
Published: June 2014

In today’s globalized world, knowledge management (KM) has become an essential tool for achieving economic growth, corporate development and competitiveness. Knowledge management must also involve a balance between good practices and productive processes. Therefore, acquisition of knowledge (generation of ideas and opportunities), as well as its implementation in processes, where it can be put into practice, is of great importance. The objective of this paper is to propose action lines to solve the problems inherent in collaborative knowledge management related technological barrier from the perspective of Project Management. Among the results highlights the application of ISO 21500:2012 international standard on good practices in Project Management, which helps establish a framework for Project Managers that helps them manage key aspects such as deadlines, cost and deliverables, achieving stakeholders’ satisfaction, which are related to appropriate management of collaborative networks.
Study of a Clayey Soil Used in the Fabrication of Red Ceramics in Campos Dos Goytacazes, Brazil
Authors: Alexandre Jonas , de Azevedo Afonso Rangel Garcez , Xavier Gustavo de Castro , Pedroti Leonardo Gonçalves , Vieira Carlos Maurício Fontes , Monteiro Sergio Neves
Published: June 2014

In the municipal area of Campos dos Goytacazes, the largest city in the northern region of the state of Rio de Janeiro, southeast of Brazil, there is a clay ceramic industrial pole comprising more than one hundred companies dedicated to the production of bricks, roofing tiles and structural blocks for civil construction. Currently, an estimated production of almost one billion pieces a year attends not only the state of Rio de Janeiro but also the neighbor states of Minas Gerais and Espírito Santo. In this work the characteristics and technical properties of the precursor clayey soil used by one of the leading local industry was studied. The initial characterization was performed by means of granulometric test, based on sieving and sedimentation methods, that allowed the separation of the material in its clay, silt and sand fractions. These fractions were chemically analyzed to evaluate the predominance of oxide content. The fluidity and plasticity limits as well as the apparent density were measured for clay bodies according to the standards. After sintering clay bodies at 700 and 900°C the ceramic technical properties of linear shrinkage, water absorption, apparent density and flexural strength were calculated following the norms. The results indicated that the precursor clay in Campos dos Goytacazes could be used for bricks but need to be incorporated with fluxing compounds to attend the requirements for structural blocks and roofing tiles.
Synthesis and Characterization of Zirconium Oxide Systems with Yttrium Rich Rare Earth Concentrate Additives
Authors: Cajas Paola Cristina , Muñoz R. , Rodríguez A.C. , Rodríguez-Páez J.E. , da Silva C.R.M.
Published: June 2014

In this work, the yttrium rich rare earth concentrate (Re2(CO3)3) was used as additive aiming stabilization of cubic an tetragonal phases at commercial zirconium oxide with 3% mol of yttrium oxide. The use of high purity rare earth oxide as additive is being commercially used and this work aims to demonstrate the potential use of lower cost additives to produce solid electrolyte for oxygen sensors and fuel cell applications. The powders for the additive production were synthesized by the controlled precipitation method. After synthesis, the powders were de-agglomerated using mechanical grinding and mixed to commercial zirconia to produce the compositions ZrO2:3% Mol Y2O3:ƞ % Mol Re2O3 (ƞ=3,4,5,6), followed by uniaxial press and sintering at 1500 0C in two hours. The obtained sintered densities were above 96% of theoretical. X-Ray diffractometric analysis and Rietweld refinement demonstrated the stabilization of cubic and tetragonal phases for all samples with yttrium rich rare earth concentrate additives. Finally the electric behavior of the evaluated samples was carried out with complex impedance spectroscopy, showing conductivity improvement for samples with the chosen additive. At 500 0C the sample A-9% had a conductivity of 1,11E-3Ω-1.cm-1, well above of the sample without additive with conductivity 5,88E-4Ω1.cm-1, indicative that use of yttrium rich rare earth concentrate as additive increases considerably the ionic conductivity of comercial zirconium oxide. Key words: rare earth concentrate, controlled precipitation, ionic conductivity
Nanostructured Co3O4 Oxide for Low Temperature Ethanol Oxidation
Authors: Gomez-Cuaspud Jairo Alberto , Schmal Martin
Published: June 2014

We investigated the synthesis of nanosized Co3O4 oxide by the polymerization-combustion technique, with different concentrations (3, 12 and 25% w/w) in the ethanol oxidation reaction. Characterization was done by X-ray fluorescence analysis, X-ray diffraction, temperature programmed reduction, scanning and transmission electronic microscopy and CO and H2 chemisorption. Principal results from physicochemical characterization show that the concentration of the metal oxide influence the product distribution and selectivity under isothermal conditions at 420 °C showed the formation of intermediate etoxi-species and preferential dehydrogenation reaction on stream of material. Specific concentrations result in high conversions and H2 selectivity under present reaction conditions.
Effect of the Iron Doping on the Thermal Decomposition of the Polymeric Precursor for the Titanium Dioxide Powder Synthesis
Authors: Lopes Silvanice A. , Cruz Natali A. , Manfroi Daniela C. , Dias Rafael Gomes , Silva Margarete S. , Zaghete Maria Aparecda , dos Anjos Ademir , Cavalheiro Alberto A. , Oliveira Lincoln C.S.
Published: June 2014

The Polymeric Precursor Method has proved suitable for synthesizing reactive powders using low temperatures of calcination, especially when compared with conventional methods. However, during the thermal decomposition of the polymeric precursor the combustion event can be releases an additional heat that raises the temperature of the sample in several tens of degrees Celsius above the set temperature of the oven. This event may be detrimental to some material types, such as the titanium dioxide semiconductor. This ceramic material has a phase transition at around 600 ° C, which involves the irreversible structural rearrangement, characterized by the phase transition from anatase to rutile TiO2 phase. The control of the calcination step then becomes very important because the efficiency of the photocatalyst is dependent on the amount of anatase phase in the material. Furthermore, use of dopant in the material aims to improve various properties, such as increasing the absorption of radiation and in the time of the excited state, shifting of the absorption edge to the visible region, and increasing of the thermal stability of anatase. In this work, samples of titanium dioxide were synthesized by the Polymeric Precursor Method in order to investigate the effect of Fe (III) doping on the calcination stages. Thermal analysis has demonstrated that the Fe (III) insertion at 1 mol% anticipates the organic decomposition, reducing the combustion event in the final calcination. Furthermore, FTIR-PAS, XRD and SEM results showed that organic matter amount was reduced in the Fe (III)-doped TiO2 sample, which reduced the rutile phase amount and increased the reactivity and crystallinity of the powder samples.
Banana Aqueous Extract as a Potential Addition to Clay Ceramics
Authors: de Aguiar Mariane Costalonga , Rodrigues Lara Pessin , Guedes Flaviane Helena , Alexandre Jonas , de Azevedo Afonso Rangel Garcez , Monteiro Sergio Neves
Published: June 2014

Clays mined in the state of Espirito Santo, Brazil, are basically kaolinitic with refractory behavior. Sintering of these clays for the fabrication of red ceramic products such as bricks, tiles and structural blocks usually requires addition of fluxing agents to consolidate the ceramic structure. The banana plant has potassium as one of its major nutrients, which exists in a relatively higher amount associated with the plant lignocellulosic constitution. Since potassium compounds are also fluxing agents for clay ceramics, the present work evaluates the effect of an aqueous extract obtained from the banana plant, for plastic behavior, into a clayey mixture before firing at conventional temperatures of 700 and 900°C. The results of this banana aqueous extract addition revealed that, within standard deviations of the evaluated properties, there was no apparent improvement but only a slightly tendency of undesirable increase in the ceramic linear shrinkage at 900°C firing temperature.
Degradation of Red Ceramic with Incorporated of Petroleum Waste
Authors: Gomes R.F. , Xavier Gustavo de Castro , Saboya F.A.J. , Maia P.C.A. , Alexandre J. , Pedroti L.G.
Published: June 2014

The red ceramic pieces Campos-RJ degrade easily when they are in the built environment. With the intention to reduce the degradation in these pieces, was introduced petroleum coke in red ceramic. Petroleum coke is a solid fossil fuel, black in color and about granular form. With percentage of 0%, 0.5%, 1% and 1.5% clay added to the coke were obtained is prismatic ceramic samples. After drying at 110 ° C, fired at 800°C and 900°C and carried out at accelerated degradation in the laboratory by degradation equipment, obtaining the technological properties and Weibull distributions before and after degradation in the samples. The 900°C gave the highest Weibull modulus (m = 12.50) compared with the firing pieces at 800°C. The results show that the incorporation of 0.5% of petroleum coke improves the Weibull modulus of the degraded material.
Improvement of Rheological Properties of Little Noble Varieties from Boa Vista Bentonites - Part I: Experimental Design
Authors: Marques Verônica Cavalcanti , Dias Iago Bruno Campos , Alves Jefferson Bezerra , Campos Liszandra Fernanda Araújo , Dutra Ricardo Peixoto Suassuna , Ferreira Heber Sivini
Published: June 2014

The noble variety of the Boa Vista bentonites became scarce, originating fluids which do not answer the Petrobras specifications. The utilization of a blending with available samples have been used in industry successfully. Thus, the present work aims to use the mixture modeling methodology with design in simplex-centroid network and further purification by hydrocycloning, trying to optimize rheological properties of dispersions prepared with little noble clays, obtaining drilling fluids that attend the normative requirements. Initially, the rheological behavior of dispersions on each of the five clays, activating them in proportions of 50, 75, 100, 125 e 150 meq of Na2CO3/100 g of dry clay. After result analyzing, the mixtures were formulated, using experimental planning with the five clays, but with activation in proportions of 100 and 125 meq of Na2CO3/100 g of dry clay.
Total and Partial Replacement of Quartz in Aluminum Hydroxides Porcelain Formulations
Authors: Gralik Guilherme , Chinelatto Adriana Scoton Antonio , Chinelatto Adilson Luiz
Published: June 2014

Alumina has been studied as a substitute for quartz triaxial porcelain formulations, but the high cost of the alumina raises the cost of production. The use of aluminum hydroxide from the Bayer process for obtaining aluminum, a source of alumina, is an alternative to alumina. In this work we used two aluminum hydroxides to replace the quartz composition of triaxial porcelain. The raw materials used were characterized by analysis of particle size distribution, scanning electron microscopy, diffraction and X-ray fluorescence. The compositions sintered were characterized by apparent density, apparent porosity, water absorption, flexural strength, and X-ray diffraction and scanning electron microscopy. Both the total and partial replacement of quartz by aluminum hydroxide showed good results with high flexural strength, low water absorption and low porosity.
Study of the Effect of Feldspar Replacement from a Mixture of Glass / Syenite in Technological Properties of Ceramic Coatings
Authors: Filho José Elson Soares , de Oliveira Feitosa Alan , dos Santos Leonardo Leandro , Campos Liszandra Fernanda Araújo , Dutra Ricardo Peixoto Suassuna
Published: June 2014

Obtaining new raw materials for the production of ceramic coating is increasingly highlighted, however, it is desirable to maintain or improve the technological properties of the formed product. Thinking about it, and aiming at the environmental context, the aim of this work is to study the mixing recycled glass effect with syenite, an alternative melting often used in the production of ceramic tiles, in replacing to feldspar. The raw materials were characterized and subsequently the technological properties were determined for the standard formulation and the formulations with 5, 10, 15 and 20% mixing glass / syenite, in replacing to feldspar. The test bodies were prepared by wet, and sintered at different temperatures, with a rate of 30 °C /min and a level of 20 minutes. The results indicate that the mixing glass / syenite has the potential to be used as melting material in the composition of the ceramic mass.
Characterization of a Limestone Powder Residue for Recycling as a Concrete Block Incorporation
Authors: Alexandre Jonas , de Azevedo Afonso Rangel Garcez , Xavier Gustavo de Castro , Pedroti Leonardo Gonçalves , Vieira Carlos Maurício Fontes , Monteiro Sergio Neves
Published: June 2014

The mining and processing of limestone in the state of Rio de Janeiro, southeast of Brazil, generates a considerable amount of small particles, like a powder ,which is commercialized as a by product. In principle, this inert limestone powder could be recycled as part of another civil construction material. Thus, the objective of this work was to characterize a limestone powder by its physical properties, chemical analysis and microstructural aspects. The results were compared with the characteristics of a common cement and a conventional sand to be possibly applied in the fabrication of limestone incorporated concrete blocks. It was found that the limestone powder has physical, chemical and microstructural characteristics satisfactory for concrete blocks incorporation.
Development and Characterization of the Al2O3-YAG Ceramic Composites
Authors: Lima Eduardo Sousa , Santos A.P.O. , Itaboray L.M. , Santos C. , Cabral R.F.
Published: June 2014

YAG (Y3Al5O12) and Al2O3 ceramics have high resistance to oxidation and corrosion in harsh environments and high temperatures, which turns into a quite attractive material as compared to other ceramics. Thus, lately oxide ceramic YAG has been extensively used as reinforcement phase to Al2O3 in order to obtain a composite with improved mechanical properties. This research focused on the development of sintered Al2O3-Y2O3 powder mixtures for the production of Al2O3-YAG composite. Powder mixtures composed of 63.65:36.35wt.% and 80.00:20.00wt.% of Al2O3 and Y2O3, respectively, were milled by planetary milling for 2h. The compositions were compacted by cold uniaxial pressing, at 70 MPa, for 30s. The two mixtures were sintered at 1500 and 1600°C for 3h. The samples were evaluated for relative density, shrinkage, weight loss, and X-Ray Diffraction (XRD). Scanning Electron Microscopy (SEM) was used for microstructural characterization. The X-Ray Diffraction showed the presence of Al2O3 and Y3Al5O12 as crystalline phases in both compositions. Samples composed by 80:20wt.% of Al2O3/Y2O3 powder sintered at 16000C-3h presented the higher relative density ranging around 86% of theoretical density.
Synthesis by Combustion Reaction of the System Zn0,6Fe0,4O for Application as DMS: Avaliation of the Type of Container
Authors: Machado Lucius Vinicius Rocha , Souza Diogenes M.P. , Gomes Nilman D.S. , da Silva Manoel Ribeiro , Mouzinho Lucilene F. , Costa Ana Cristina Figueredo Melo
Published: June 2014

This paper proposes to investigate the influence of the type of container on the structure, morphology and measures magnetic nanoparticles of the Zn0.6Fe0.4O synthesized by combustion reaction, for use as diluted magnetic semiconductors (DMSs). For synthesis were used as containers stainless crucibles and porcelain. The heating was realized in a muffle furnace at 500 °C. During the reactions, were performed measurements of the maximum temperature and total time of combustion reaction. The synthesized samples were characterized by XRD, SEM and magnetic measurements. The maximum temperatures obtained were 478 and 456 °C and total reaction time of 285 and 195 s for the samples synthesized in the crucible of stainless steel and porcelain, respectively. In both containers were possible to obtain single phase material with average crystallite size of 26 to 37 nm, irregular agglomerates formed by, behavior ferrimagnetic whose, saturation magnetization values of 1.6 e 2.0 emu/g respectively.