oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 8 )

2018 ( 134 )

2017 ( 129 )

2016 ( 117 )

Custom range...

Search Results: 1 - 10 of 2917 matches for " Microstructure "
All listed articles are free for downloading (OA Articles)
Page 1 /2917
Display every page Item
Engineering of microstructures
DeHoff, R.T.;
Materials Research , 1999, DOI: 10.1590/S1516-14391999000300002
Abstract: structure is at the heart of the materials science paradigm connecting processing with properties. in the hierarchy of structures that exist in materials microstructure offers the richest variety of structural arrangements. this variety is often conveniently accessible, e.g., simply by heat treatment or mechanical deformation. exploration of the relation between properties and microstructure serves to establish a target range of microstructural states that will perform. in order to attain a target microstructure it is necessary to understand what microstructures are, and how they evolve in processing. this presentation focuses upon the set of tools that must be combined to achieve this control: 1. geometry 2 thermodynamics 3. kinematics 4. kinetics. the content of these tools is reviewed briefly and their uses illustrated in developing an understanding of how microstructures evolve. in this development an attempt is made to carry the description of each microstructural process as far as possible without making simplifying assumptions. the study of microstructures with this rigorous point of view was termed by f.n. rhines, "microstructology".
Engineering of microstructures
DeHoff R.T.
Materials Research , 1999,
Abstract: Structure is at the heart of the materials science paradigm connecting processing with properties. In the hierarchy of structures that exist in materials microstructure offers the richest variety of structural arrangements. This variety is often conveniently accessible, e.g., simply by heat treatment or mechanical deformation. Exploration of the relation between properties and microstructure serves to establish a target range of microstructural states that will perform. In order to attain a target microstructure it is necessary to understand what microstructures are, and how they evolve in processing. This presentation focuses upon the set of tools that must be combined to achieve this control: 1. Geometry 2 Thermodynamics 3. Kinematics 4. Kinetics. The content of these tools is reviewed briefly and their uses illustrated in developing an understanding of how microstructures evolve. In this development an attempt is made to carry the description of each microstructural process as far as possible without making simplifying assumptions. The study of microstructures with this rigorous point of view was termed by F.N. Rhines, "microstructology".
Indentation Creep Behavior and Microstructure of Cu-Ge Ferrites  [PDF]
Hesham Mohaned Zaki, Ali Mohamed Abdel-Daiem, Yahia Ibrahim Swilem, Farid El-Tantawy, Fahad Masoud Al-Marzouki, Ahmed Abdallah Al-Ghamdi, Saleh Al-Heniti, Farag Said Al-Hazmi, Talal Sadaka Al-harbi
Materials Sciences and Applications (MSA) , 2011, DOI: 10.4236/msa.2011.28145
Abstract: Cu-Ge ferrite was prepared using the standard ceramic method. The creep rate of polycrystalline Cu1+xGexFe2-2xO4 ferrite has been measured as a function of time at room temperature. It is found that the indentation length increases with the increase of both time and applied load. A regime of individual creep curves is observed for the first and second stages. It is not possible to record the third stage of the curve as usually happened in an ordinary creep test, because fracture of the samples does not occur. The slope is found to increase with increasing germanium and copper content in the steady state region. The high value of n (stress exponent factor) indicates that the dislocation creep is the dominate mechanism. The porosity arrangements developed within the specimens were examined using optical microscope. The results are discussed with regard to models describing the role of the steady state creep rate of metals. The morphology of the samples shows that the porosity is increased by increasing both copper and germanium ions.
Scanning Electron Microscopy of Some Slowly Cooled Nickel-Based Hardfacing Alloys Containing Iron Additions  [PDF]
J. A. Ajao
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2010, DOI: 10.4236/jmmce.2010.92012
Abstract: The service lifespan of components used at higher temperatures in corrosive and abrasive environments can be prolonged by high-temperature corrosion-resistant coatings. This study is concerned with the microstructural characterization of some slowly cooled Nickel–based hardfacing alloys investigated by differential thermal analysis (DTA), energy dispersive X – ray analysis (EDXA), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The alloys were prepared in high frequency induction furnace under controlled atmosphere. Three major primary hard phases (Ni (α), M7C3, and the π phase) were identified during slow cooling in DTA depending on the nominal compositions of the alloys. Large undercoolings as well as intense solid state precipitations were observed in alloys with iron additions. The precipitations formed the basis of the high hardness values and strength of the alloys. It was also reported that the hardness values of the alloys increased as the iron contents increased.
Microstructures and Photovoltaic Properties of Polysilane/C60-Based Solar Cells  [PDF]
Atsushi Kawashima, Takeo Oku, Atsushi Suzuki, Kenji Kikuchi, Shiomi Kikuchi
Materials Sciences and Applications (MSA) , 2012, DOI: 10.4236/msa.2012.38079
Abstract: Polysilane/C60-based solar cells were fabricated and investigated. Two-types of devices with bulk heterojunction and heterojunction structures were examined and characterized. Addition of silicon-based polymer to the organic solar cells improved the conversion efficiency by wide optical absorption and high carrier mobility. Microstructures of the solar cells were investigated by using X-ray diffraction and transmission electron microscopy. Energy levels in the present solar cells were discussed.
Influence of Microstructure on Beneficiation of Low-Grade Siliceous Manganese Ore from Orissa, India  [PDF]
Patitapaban Mishra, Birendra Kumar Mohapatra, Pradeep Kumar Mallick, Khageswar Mahanta
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2013, DOI: 10.4236/jmmce.2013.13015
Abstract: Two low-grade siliceous manganese ores such 1) siliceous crystalline and 2) siliceous cherty types from north Orissa, Indiawas mineralogically characterized and investigated for their possible upgradation. Both the Mn-ore types were subjected to different physical beneficiation techniques under identical conditions and results reported. The results revealed that in the case of low-grade siliceous crystalline type Mn-ore a feed having 26% Mn could be upgraded to more than 45% Mn by dry magnetic separation with 69% recovery at 1.00 tesla magnetic intensity. But the cherty type Mn-ore could not respond well to any of the beneficiation techniques, particularly dry magnetic separation, because of poor liberation even at a size fraction below 100 mesh, though the other type gives best result at this size fraction.
Optical Microstructure Design Optimization for Display Backlighting  [PDF]
Chi-Chang Hsieh, Yan-Huei Li
Modern Mechanical Engineering (MME) , 2013, DOI: 10.4236/mme.2013.34027
Abstract:

This study proposes an innovative design method for functional optical film microstructures used in displays and applies this design to LCD backlighting to replace multi-layer optical film functional integration with composite optical film. We design a novel optical film microstructure based on light uniformity and wide-angle lumination distribution and determine the optimal optical microstructure parameters by combining the global optimization of a genetic algorithm with ray tracing. The purpose of this study is to develop substitutes for traditional multi-layer prism brightness enhancers and light-diffusing film stacks and to examine the structural changes during calculations and summarize the characteristics. In this study, we focus on determining the optimal light uniformity of new optical film microstructures. The seven-inch LED backlight module of the method proposed in this study achieved 94.59% uniformity and 168° lumination distribution while reducing thickness by 66% to 82% compared to a traditional multi-layer optical film stack.

In Vivo Preliminary Study on Bone Neoformation Behavior of Three Types of Calcium Phosphate Bioceramics  [PDF]
Nelson H. A. Camargo, Enori Gemelli, Aury N. de Moraes, Bruna D. da Costa, Nilson Oleskovicz, Ademar L. Dallabrida, Doughlas Regalin, Marcos Paulo Antunes de Lima
Journal of Biosciences and Medicines (JBM) , 2014, DOI: 10.4236/jbm.2014.22006
Abstract:

Calcium phosphate microporous bioceramics and biphasic compositions of hydroxyapatite and β-calcium phosphate, in the form of microporous granular biomaterials, are research topics and present themselves as potential orthopedic and biomedical applications in rebuilding and repairing maxillofacial bones and tooth structure. This is associated with the characteristics of microstructure, biocompatibility, bioactivity and bone conductivity properties which these materials offer when applied in vivo or in a simulation environment. This study aimed to assess the behavior of bone neoformation of three types of calcium phosphate biomaterials in in vivo tests with sheep within 60 and 90 days, with the help of a scanning electron microscope. The biomaterials used were provided by the Group of Biomaterials at the Santa Catarina State University. The in vivo tests were carried out by generating, on sheep, tibial bone defects, three of which were filled with biomaterial (one different biomaterial for each bone defect generated), whilst the fourth received a bone fragment obtained during the generation of the defect in question, to serve as a control group. The scanning electron microscopy (SEM) technique was used for carrying out the preliminary characterization studies so as to observe new bone formation and osseointegration. The X-ray diffractometry (XRD) served as a support for the characterization of crystalline phases. The results obtained are encouraging and show that the biomaterials presented good performance in the process of bone formation, biomaterial osseointegration by a new tissue and bone mineralization.

Potential Utilization of Solid Waste (Bagasse Ash)  [PDF]
V. S. Aigbodion, S. B. Hassan, T. Ause, G.B. Nyior
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2010, DOI: 10.4236/jmmce.2010.91006
Abstract: Utilization of industrial and agricultural waste products in the industry has been the focus of research for economical, environmental, and technical reasons. Sugar-cane bagasse is a fibrous waste-product of the sugar refining industry, along with ethanol vapor. This waste-product is already causing serious environmental pollution which calls for urgent ways of handling the waste. In this paper, Bagasse ash has been chemically and physically characterized, in order to evaluate the possibility of their use in the industry. X-ray diffractometry determination of composition and presence of crystalline material, scanning electron microscopy/EDAX examination of morphology of particles, as well as physical properties and refractoriness of bagasse ash has been studied.
Processing of 5083 Aluminum Alloy Reinforced with Alumina through Microwave Sintering  [PDF]
Jagesvar Verma, Anil Kumar, Rituraj Chandrakar, Rajesh Kumar
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2012, DOI: 10.4236/jmmce.2012.1111121
Abstract: Today, there is an increasing demand worldwide for the advanced materials in order to obtain the desired properties. This is because a single material generally cannot meet the requirement of harsh engineering environment that is why the need for composites arises. Metal matrix composite is an important class of materials with high potential for structural applications requiring high specific modulus, strength and toughness. Metal matrix composites with unique properties are growing every day and widely used in different industries because of their high mechanical properties and wear resistance.
Page 1 /2917
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.