This article discusses postconsumer plastics recyclate quantities, the classification of plastics recycling into primary, secondary, tertiary, and quaternary categories, and how the life cycle of plastics is affected by recycling. The recycling processes of polyethylene terephthalate (PET), which accounts for the largest percentage of plastic recycling, high-density polyethylene (HDPE) plastics, the other large-volume plastic recyclate, as well as vinyl resins and polycarbonate resins are described. The life cycle of plastics has four phases: poly formation, part fabrication, product service, and disposal. Landfilling is still the primary method of final disposal, and incineration is another option, but recycling has become a viable alternative. The article presents a comparison between secondary and tertiary recycling.

This article begins with a discussion on the driving forces for recycling composites. It reviews the recycling process of thermoset-matrix composites and thermoplastic-matrix composites. The recycling of thermoset-matrix composites includes regrind, chemical, energy recovery, and thermal processes. Thermoplastic-matrix composites are recycled by regrinding, compounding/blending and reprocessing. The article concludes with discussion on the properties of recycled composite fibers.

Compression molding is the single largest primary manufacturing process used for automotive composite applications. This article provides an overview of the compression molding process. It describes the basic design, materials, and processing equipment of three main groups of composite materials, namely, glass-fiber-mat-reinforced thermoplastics, long-fiber-reinforced thermoplastics, and sheet molding compounds. The article also presents information on the application examples and market volume of compression molding.

This article discusses the methods for assessing creep-rupture properties, particularly, nonclassical creep behavior. The determination of creep-rupture behavior under the conditions of intended service requires extrapolation and/or interpolation of raw data. The article describes the various techniques employed for data handling of most materials and applications of engineering interest. These techniques include graphical methods, methods using time-temperature parameters, and methods used for estimations when data are sparse or hard to obtain. The article reviews the estimation of required creep-rupture properties based on insufficient data. Methods for evaluation of remaining creep-rupture life, including parametric modeling, isostress testing, accelerated creep testing, evaluation by the Monkman-Grant coordinates, and the Materials Properties Council (MPC) Omega method, are also reviewed.

The article presents an in-depth discussion on the various additive manufacturing techniques such as binder jetting, directed-energy deposition, material extrusion, material jetting, powder-bed fusion, sheet lamination, and vat polymerization processes. This article then discusses the different critical material aspects of additively manufactured medical devices, beginning with the preprinting phase (material consistency and recycling), the printing phase (build orientation), and the postprinting phase (part evaluation, biocompatibility, and sterilization) with supporting materials.

This article discusses the three basic elements of an epoxy resin formulation that must be understood when selecting a thermoset system. These include base resins, epoxy resin curatives, and modifiers. The article provides examples of epoxy resin formulations that illustrate how raw materials are combined to tailor a formulation to a specific application. It concludes with a discussion on general guidelines for the safe handling of epoxy resins and their associated products.

Functional fusion-bonded epoxy (FBE) coatings are used as external pipe coatings, base layer for three-layer pipe-coating systems, internal pipe linings, and corrosion coatings for concrete reinforcing steel (rebar). This article provides information on the chemistries of FBE, and discusses the application procedures for internal and external FBE pipe coating. The procedures involve pipe inspection, surface preparation, heating, powder application, curing, cooling, coating inspection, and repairing. It describes the problems and solutions for FBE external pipe coatings, girth weld FBE application, FBE custom coatings, internal FBE pipe linings, and FBE rebar coatings.

This article provides an overview of polymer fractography, with examples of various fracture surfaces created under diverse loading conditions. The focus is on the interpretation of polymer fracture-surface features in light of the unique viscoelastic nature of polymers. The article presents fractographic examples of three time-dependent cracking mechanisms: fatigue fracture, creep rupture, and environmental stress cracking. It details characteristic fractographic features that can be observed in optical microscopy (OM) and scanning electron microscopy (SEM).

Ores, which consist of the primary valuable mineral, predominant gangue content, valuable by-products, and detrimental impurities, are extracted and directed to mineral processing. This article describes the mineral processing facilities, such as crushers, grinders, concentrators, separators, and flotation devices that are used for particle size reduction, separation of particles according to their settling rates in fluids and dewatering of concentrate particles. It explains the basic principles, flow diagrams, ore concentrate preparation methods, and equipment of major types of metallurgical processes, including pyrometallurgical, hydrometallurgical, and electrometallurgical processes.

When a heat of steel is melted and refined, it is necessary to solidify it into useful forms for further processing or final use. Ingot casting remains the preferred method for certain specialty, tool, forging, and remelted steels. This article discusses the methods, equipment, and theory for pouring, solidifying, and stripping steel ingots. It describes two basic types of pouring methods, top pouring and bottom pouring, and provides information on equipment such as hot tops, ingot molds, and stools. The design of the ingot is dictated by the application and type of steel involved. The article concludes with information on the applications of solidification simulation.

This article describes elastomeric coatings that are suitable for painting flexible plastic substrates. It focuses on coatings systems that find utility in automotive exterior applications, where the requirements of appearance and durability are most severe. The article discusses acrylic polyols, condensation polymers, vapor curing systems, water-based coatings, and coatings for thermoplastic olefins.

This article provides information on the municipal wastewater system components such as piping, pump stations, headworks, clarifiers, aeration structures, digesters, biosolids dewatering equipment, and sludge stabilization. It explains the major corrosion damage mechanisms to which those component parts of the system are exposed. It presents useful guidelines for selecting and using protective coatings in municipal sewerage collection systems and water reclamation facilities in wastewater treatment plants. The article includes annotated flow diagrams of a wastewater collection system, wastewater treatment plants, and spreadsheets listing the most widely used generic coating systems by structure and substrate material. It concludes with a section on quality watchouts when selecting or using protective coatings in municipal wastewater systems.

The inhibitors currently in use are generally complex mixtures of reaction products and have been formulated to meet the demands of a very competitive industry. This article discusses these demands on inhibitor formulation. The varying characteristics and number of organic inhibitors are explained by the varying characteristics of oil wells and gas wells. Water injection systems and pipelines are also discussed. The article describes the factors that influence the corrosivity of produced fluids and the various treatments applicable for oil, gas, and pumping wells. It examines the primary causes of corrosion inhibition in waterfloods: oxygen contamination and acid gases dissolved in the brine. A discussion on the bacteria-induced corrosion is provided. The article also explains various tests available for field corrosion monitoring. It details the methods used to monitor corrosion rates and inhibitor effectiveness. The article concludes information on the computerization of inhibitor treating programs.

This article describes the synthesis, manufacturing, and properties of both the neat soy-based resins and the glass, flax, and hemp composites. A tabulation of the fatty-acid distribution in various plant oils is provided. The article discusses synthetic pathways for triglyceride-based monomers and provides a discussion on acrylated epoxidized soybean oils (AESO), maleinized soyoil monoglyceride (SOMG/MA), and maleinized hydroxylated oil (HO/MA). The polymer properties of the AESO, SOMG/MA, and HO/MA are also discussed. The article explains the ballistic impact resistance of soy resin composites and concludes with a discussion on biodegradable composites.

This article reviews the basic types of mold aggregates and bonding methods for expendable molds and coremaking. It provides an overview of mold media and the basic types of sands and their properties. The most significant clays used in green sand operations, such as bentonites, are discussed. The article describes the methods of sand bonding with inorganic compounds. It provides a description of resin-bonded sand systems: no-bake binder systems, heat-cured binder systems, and cold box binder systems. The article concludes with a discussion on the media used for expendable molds, namely, ceramic shells and rammed graphite, for casting reactive metals such as titanium or zirconium.

This article briefly describes the production of beryllium powder and beryllium/beryllium oxide metal-matrix powder. It discusses fully dense consolidation methods: vacuum hot pressing, hot isostatic pressing, and cold isostatic pressing. Secondary fabrication operations of beryllium and aluminum-beryllium alloys such as extrusion, rolling, welding, joining, and machining are discussed. The article discusses quality control and provides information on the structural, optical, and high-purity grades of beryllium.

This article presents the use of additive manufacturing (AM) in the space industry. It discusses metal AM processes and summarizes metal AM materials, including their relevant process categories and references. It also presents the design for AM for spacecraft. The article also provides an overview of in-space manufacturing and on-orbit servicing, assembly, and manufacturing. It presents some of the specific areas that must be understood for the qualification of AM. The article also discusses future trends, challenges, and opportunities for aerospace.

This article is a compilation of definition of terms related to materials selection and its integration with engineering design processes.

This article discusses the methods of pulp production, pulp processing, pulp bleaching, and paper manufacturing. It describes various types of digesters, their construction materials, the corrosion problems encountered, and methods to protect these digesters from corrosion. The article examines the corrosion problems in high-yield mechanical pulping, sulfite process, neutral sulfite semichemical pulping, chemical recovery, tall oil plants, wastewater treatment, and recovery boilers. It explains the stages of chlorine-based and nonchlorine bleaching, process water reuse for elemental chlorine-free and nonchlorine bleaching stages, selection of material for bleaching equipment, developments in oxygen bleaching, and the use of highly corrosion-resistant materials for bleach plant equipment. The article reviews the materials used in the construction of paper machine components and specific corrosion problems that affect them. It discusses the composition and corrosive nature of white water. The article also addresses the corrosion and chemical recovery associated with kraft pulping liquors.