Search Results for data-mining technique

A computational tool would require the contribution of the strengthening mechanisms of metallic material to be predicted and then summed in an appropriate way to derive an estimate of the tensile properties. This article focuses on the modeling of deformation mechanisms pertinent to structural materials, namely, solid-solution strengthening, age/precipitation hardening, dispersion strengthening, grain size reduction, strengthening from cold work, and strengthening from interfaces. It explains the application of predictive models in the atomistic modeling of dislocation structures and cast aluminum property prediction. The article concludes with information on the use of rules-based approaches and data-mining techniques for quantitative predictions of tensile properties.

Gallium-base components can be found in a variety of products ranging from compact disk players to advanced military electronic warfare systems, owing to the factor that it can emit light, has a greater resistance to radiation and operates at faster speeds and higher temperatures. This article discusses the uses of gallium in optoelectronic devices and integrated circuits and applications of gallium. The article discusses the properties and grades of gallium arsenide and also provides information on resources of gallium. The article talks about the recovery techniques, including recovery from bauxite, zinc ore and secondary recovery process and purification. The article briefly describes the fabrication process of gallium arsenide crystals. Furthermore, the article gives a short note on world supply and demand of gallium and concludes with research and development on gallium arsenide integrated circuits.

This article focuses on the use of indium and bismuth in low-melting-temperature solders and fusible alloys. It describes how the two elements typically occur in nature and how they are recovered and processed for commercial use. It also provides information on designations, classification, composition, properties (including temperatures ranges), and some of the other ways in which indium and bismuth alloys are used.

Dual-phase steels are a new class of high-strength low alloy (HSLA) steels characterized by a microstructure consisting of about 20% hard martensite particles dispersed in a soft ductile ferrite matrix. In addition to high tensile strength, in the range of 550 MPa (80 ksi), dual-phase steels exhibit continuous yielding behavior, a low 0.2% offset yield strength, and a higher total elongation than other HSLA steels of similar strength. The article discusses some of the more pertinent aspects of dual-phase steels, such as heat treatment, microstructure, mechanical properties, chemical composition, and manufacturability. In general, these steels have a carbon content of less than 0.1%, which ensures that they can be spot welded. However, newer high-carbon dual-phase steels in development are generating interest due to their unique combination of total elongation and tensile strength.

This article describes the corrosion of principal parts of mining equipment such as mine shafts, wire rope, rock bolts, and pump and piping systems. It discusses the diagnosis and prevention of various types of corrosion including uniform corrosion, pitting corrosion, crevice corrosion, erosion-corrosion, and intergranular corrosion. The article explains the corrosion in tanks, reactor vessels, cyclic loading machinery, and pressure leaching equipment.

Ion chromatography (IC) is an analytical technique that uses columns packed with ion exchange resins to separate ions in aqueous solutions and dynamically elute them to a detector. This article provides information on the different modes of detection, namely, eluent-suppressed conductivity detection, single-column ion chromatography with conductivity detection, ion chromatography with spectrophotometric detection, and amperometric electrochemical detection. It describes the modes of separation techniques in IC and reversed-phase IC. The article discusses the detection capabilities of IC, the procedures for preparing solid and liquid samples, as well as the applications of IC.

This article presents the importance of progressing from post-manufacturing inspection/verification to in-process inspection/verification methods. It lists the various quality assurance factors considered for typical composite laminate lay-up process. The article provides information on composite cure tooling that is fabricated from steel, aluminum, or high-temperature composite materials. The quality assurance for commercial applications is reviewed. The article concludes with a discussion on data fusion systems designed to provide nondestructive analysis data from fabrication and assembly processes for each individual composite part.

This article briefly describes the capabilities of gas chromatography/mass spectrometry, which is used to qualitatively and quantitatively determine organic (and some inorganic) compound purity and stability and to identify components in a mixture. The discussion covers in more detail gas chromatography/mass spectrometry (GC/MS) instrumentation, interpreting mass spectra, GC/MS methodology, and GC/MS advances. Sample preparation, which is very important in GC/MS to avoid erroneous data and to minimize maintenance and troubleshooting of the instrument, is also discussed. Further, the article highlights the state of the art in the MS detector technology.

X-ray powder diffraction (XRPD) techniques are used to characterize samples in the form of loose powders or aggregates of finely divided material that readily diffract x-rays in specified patterns. This article provides an introduction to XRPD, beginning with a review of sensing devices, including pinhole/Laue cameras, Debye-Scherrer/Gandolfi cameras, Guinier cameras, glancing angle cameras, conventional diffractometers, thin film diffractometers, Guinier diffractometers, and micro diffractometers. The article then describes several quantitative measurement methods, such as lattice parameter, absorption diffraction, spiking, and direct comparison, explaining where each may be used. It also identifies potential sources of error in XRPD measurements.

This article reviews the characterization methods for producing 3-D microstructural data sets. The methods include serial sectioning by mechanical material removal method and focused ion beam tomography method. The article describes how these data sets are used in realistic 3-D simulations of microstructural evolution during materials processing and materials response. It also explains how the 3-D experimental data are actually input and used in the simulations using phase-field modeling and finite-element modeling.

Corrosion monitoring is important in the operation of modern industrial plants and in the use and maintenance of expensive assets such as bridges and aircrafts, because the damage caused by corrosion and the rate of the deterioration can be huge and the risks devastating. This article discusses the system considerations and installation techniques of different types of direct and indirect techniques in electrochemically based on-line corrosion monitoring process. It describes the importance of probe location and on-line corrosion monitoring techniques with examples.

This article focuses on coatings and overlays adopted for use as wear- and corrosion-resistant materials in oil sand processing. It describes the most common application processes for oil sand coatings and overlays, including welding, high-velocity oxyfuel thermal spray, laser cladding, and vacuum brazing. The article provides information on the selection of overlays and materials such as chromium-carbide-base overlays and tungsten carbide metal-matrix composites.

In x-ray diffraction residual stress measurement, the strain in the crystal lattice is measured, and the residual stress producing the strain is calculated, assuming a linear elastic distortion of the crystal lattice. This article provides a detailed account of the plane stress elastic model, and describes the most common methods of x-ray diffraction residual stress measurement, namely, single-angle and two angle techniques. It elaborates the major steps involved in x-ray diffraction residual stress measurement, explaining the possible sources of error in stress measurement. The article also outlines the applications of x-ray diffraction residual stress measurement with examples.

This article describes the principles and applications of Auger electron spectroscopy (AES). It provides information on the instrumentation typically used in the AES, including an electron gun, an electron spectrometer, a secondary electron detector, and an ion gun. The article also describes experimental methods and limitations of the AES, including elemental detection sensitivity, electron beam artifacts, sample charging, spectral peak overlap, high vapor pressure samples, and sputtering artifacts.

A close-interval survey (CIS) is a series of structure-to-electrolyte direct current potential measurements performed at regular intervals for assessing the level of cathodic protection (CP) on pipelines and other buried or submerged metallic structures. This article describes the equipment required to perform the CIS. It provides a discussion on the activities that should be performed during the preparation and execution of the CIS. The dynamic stray current identification and compensation by CIS is discussed briefly. The article also explains various factors involved in the validation of CIS data. It concludes with information on CIS data interpretation.

Solid-state welding (SSW) processes are those that produce coalescence of the faying surfaces at temperatures below the melting point of the base metal being joined without the addition of brazing or solder filler metal. This article discusses the fundamentals of welding and joining materials via the application of a nonmelting process. The specific processes usually associated with the nonmelting process are discussed.

This article provides an overview of cost analysis in materials selection. It discusses the several categories of alternatives for cost analysis. These include rules of thumb, accounting methods, and analytical methods. The article describes the methods for evaluating materials alternatives on the basis of both direct economic costs and indirect social costs. It considers the life cycle costs of alternative body-in-white designs and life cycle analysis. The various elements of cost are introduced with a case study concerned with the manufacture, use, and disposal of the automobile body-in-white.

Ultrasound is an ideal modality for nondestructive evaluation (NDE) because it enables the interior of objects to be assessed without the safety and access issues associated with radiography. This article summarizes the history of array usage in NDE and its relationship to medical applications. It discusses the mathematics behind classical beamforming, full matrix capture, and total focusing methods of imaging. The article shows how ultrasonic array data can be simulated by direct numerical methods (most commonly using finite-element methods), analytical methods, or hybrid methods. It also considers various methods of comparing the performance of arrays and imaging algorithms. The article provides a comparison of various advanced and nonlinear imaging algorithm and looks at some practical industrial applications of arrays. It concludes with some future perspectives for arrays in NDE.

This article discusses the tests designed specifically to evaluate the adhesion, friction, and wear behavior of various material systems. It tabulates the characteristics of common types of wear and mechanical surface damage. The article also considers the displaying and analyzing of adhesion, friction, and wear test data. It concludes with a description of devices used for testing adhesion, friction, and wear.

This article focuses on the recycling of metals including iron and steel, stainless steel, superalloys, nickel, aluminum, copper, precious metals, lead, magnesium, tin, titanium, and zinc. It provides information on the identification and sorting of scrap metals and discusses the equipment and procedures used for small-scale and large-scale scrapping operations.