Guided wave testing (GWT) is a method of nondestructive evaluation for the inspection of pipelines. This article focuses mainly on explaining GWT as it is applied in routine established use, covered by standards, in the oil and gas industry and also introduces some of the other contexts in which its use is growing in other evolving applications. It discusses the various guided wave modes and their selection criteria. The article provides information on considerations for mode control and the sensitivity of the GWT to the defect. It also shows some examples of advanced GWT.

This article focuses on the necessary basics for thermomechanical fusion welding simulations and provides an overview of the specific aspects to be considered for a simulation project. These aspects include the required material properties, experimental data needed for validation of the simulation results, simplifications and assumptions as a prerequisite for modeling, and thermomechanical simulation. The article concludes with information on the sensitivity of the material properties data with respect to the simulation results. It also provides hints on the central challenge of having the right material properties at hand for a specific simulation task.

This article provides guidelines for the assessment of model quality in materials science and engineering. It discusses the fundamentals of model quality assessment and the calibration of mechanistic material models. The article reviews the considerations for the model verification during software implementation planning to identify suitable programs, software components, and programming languages. It describes the validity tests used in model validation, including boundary-value tests, degenerate problem tests, sensitivity tests, and benchmarking. The article also presents an example of model calibration, verification, and validation for the prediction of martensite start temperature of steels.

This article begins with an overview of classes and applications of gray iron. It discusses the castability of gray iron in terms of section sensitivity and fluidity. The article provides information on the dimensions of prevailing sections recommended for gray irons and reviews the properties and specifications of test bar. Properties of gray iron, such as fatigue limit, pressure tightness, impact resistance, machinability, and dimensional stability, at both room and elevated temperature, are reviewed. Wear behavior of gray iron castings during sliding contact under conditions of normal lubrication is also discussed. The article evaluates the use of alloys and heat treatment to modify as-cast properties. It concludes with information on the physical properties of gray iron castings.

X-ray diffraction (XRD) is the most extensively used method for identifying and characterizing various aspects of metals related to the arrangements and spacings of their atoms for bulk structural analysis. XRD techniques are also applicable to ceramics, geologic materials, and most inorganic chemical compounds. This article describes the operating principles and types of XRD analyses, along with information about the threshold sensitivity and precision, limitations, sample requirements, and capabilities of related techniques. The necessary instrumentation for XRD analyses include the Debye-Scherrer camera and the X-ray diffractometer. The article also describes the uses of XRD analyses, such as the identification of phases or compounds in metals and ceramics; detection of order and disorder transformation; determination of lattice parameters and changes in lattice parameters due to alloying and temperature effects; measurement of residual stresses; characterization of crystallite size and perfection; characterization of preferred orientations; and determination of single crystal orientations.

This article provides information on the classification, microstructure, castability and section sensitivity of gray iron. It describes properties of the test bar and provides a short note on fatigue limit in reversed bending. Although the ASTM size B test bar is the bar most commonly used for all gray irons from classes 20 to 60, ASTM A 48 provides a series of bar sizes, and the user can select the bar sizes that best approximates the cooling rate in the critical section of the casting.

ASTM specification A 48 classifies gray irons in terms of tensile strength. The usual microstructure of gray iron is a matrix of pearlite with graphite flakes dispersed throughout. Section sensitivity effects are used in the form of a wedge test in production control to judge the suitability of an iron for pouring a particular casting. Mechanical property values obtained from test bars are sometimes the only available guides to the mechanical properties of the metal in production castings. Gray iron castings are used widely in pressure applications such as cylinder blocks, manifolds, pipe and pipe fittings, compressors, and pumps. Where high impact resistance is needed, gray iron is not recommended. The machinability of most gray cast iron is superior to that of most other cast irons of equivalent hardness, as well as to that of virtually all steel. Gray iron is used widely for machine components that must resist wear.

This article provides a detailed account of the principles, instrumentation,and applications of x-ray photoelectron spectroscopy (XPS), a technique used for elemental and compositional analysis of surfaces and thin films. It reviews the nomenclature of energy states and sensitivity of electrons at the surface that are capable of producing peaks in XPS. Additionally, it presents information on the instrumentation and the preparation and mounting of samples for XPS analysis. The article explains qualitative analysis, namely, measuring of shifts in the binding energy of core electrons, multiplet splitting, and the Auger parameter; and quantitative analysis such as depth analysis carried out using XPS. It also discusses the applications of XPS with examples.