Engineering

Metalworking: processes, materials, history and applications Metalworking Comprehensive overview of metalworking: techniques for shaping and joining metals, common materials and tools, historical development, major uses, and distinctions like blacksmithi…

Microarchitecture: design and organization of processor hardware Microarchitecture Microarchitecture describes how a processor's circuits and logic implement an instruction set. This article explains components, design choices, history, and practical trade-offs i…

Micrograph: Photomicrography and Microscopic Imaging Micrograph A micrograph is a photograph made through a microscope that reveals magnified structure. This article covers types (light, SEM, TEM), preparation, applications, history and good-pr…

Mid-engine layout: design, benefits, and applications Mid-engine design Overview of the mid-engine vehicle layout, its mechanical characteristics, advantages and trade-offs, historical use in racing and sports cars, and practical considerations for des…

Military engineering: roles, history and modern practice Military engineering Summary of military engineering: tasks (mobility, countermobility, survivability, EOD), historical development from ancient siegecraft to modern combat engineers, organization and…

Mill (grinding machinery, factories, currency, and other meanings) Mill Comprehensive overview of 'mill' covering grinding devices, powered factories, specialized machines, currency units, cultural uses, and notable names and places.

Grinding Mill: Types, History, and Uses Mill (grinding) A grinding mill reduces solid materials to smaller particles. This article explains mill types, components, historical development, common applications, and safety and operational…

Millennium Force — Cedar Point's steel giga roller coaster Millennium Force Millennium Force is a landmark steel "giga" roller coaster at Cedar Point in Sandusky, Ohio. Opened in 2000, it established the 'giga' class with a 310-foot drop and remains influe…

Mortice and Tenon Joint Mortice and tenon A mortice (mortise) and tenon is a classic woodworking joint that fits a projecting tenon into a matching mortice. Strong, versatile, and ancient, it remains central to furniture a…

Moulding (molding) — shaping materials using molds Moulding Moulding is the manufacturing process of shaping liquid or pliable materials in a reusable hollow form. This article explains types, materials, tooling, history, applications and d…

Nail (fastener): history, types, manufacture and uses Nail A nail is a simple metal fastener with a head and pointed shank used since antiquity. This article explains its parts, historical development, common types, manufacturing methods a…

United States National Academy of Engineering (NAE) National Academy of Engineering Private, nonprofit academy founded in 1964 that honors engineering excellence, advises government, promotes education and research, and awards major engineering prizes.

Needle (sewing tool and related applications) Needle A needle is a small pointed implement for passing thread or performing puncturing tasks. This article covers types, parts, materials, history, uses and safety of sewing, medical an…

Negative feedback (control systems and biological regulation) Negative feedback Negative feedback is a regulatory mechanism in which a system's output acts to reduce or oppose changes to its input, used across engineering, physiology, and control theory to mai…

Neoprene: properties, production, uses, and environmental considerations Neoprene Neoprene is a family of synthetic rubbers (polychloroprene) known for flexibility, chemical and weather resistance, and used in wetsuits, gaskets, adhesives and coatings. Origins t…

NFPA 704 (Fire Diamond): Emergency Hazard Identification for Responders NFPA 704 NFPA 704, the fire-diamond system, is a concise four-quadrant marking that quickly communicates health, flammability, reactivity and special hazards for emergency response and site…

Nozzle: Function, Design, Uses, and Common Types Nozzle A nozzle is a device that directs and accelerates a fluid flow by shaping a passage. This article explains how nozzles work, their main parts, historical development, common types…

Nuclear engineering: principles, applications, and challenges Nuclear engineering An overview of nuclear engineering: its scope, core technologies, historical development, practical uses and contemporary challenges including safety, waste and proliferation.

Reactor core melt accidents: causes, corium formation, and safety measures Nuclear meltdown Reactor core melt accidents: causes, corium formation, hazards and safety measures — clear overview of how meltdowns occur, corium properties, containment risks, prevention and mit…

Nuclear reactor: principles, types, history and applications Nuclear reactor An overview of nuclear reactors: how they work, principal components and fuels, main reactor types, history and applications, safety and waste issues, and notable incidents.

Object-oriented programming (OOP): concepts, history, and applications Object-oriented programming Overview of object-oriented programming: key principles (classes, objects, encapsulation, inheritance, polymorphism), history, common languages, typical uses and notable advantages…

Occupational Safety and Health Overview of occupational safety and health (OSH): its aims, core elements, legal roles, history, practical measures, and distinctions between safety and health in the workplace.

Ocean thermal energy conversion (OTEC): principles, systems, and applications Ocean thermal energy conversion OTEC converts the ocean's surface-to-depth temperature difference into useful power, desalinated water and cooling. It includes closed, open and hybrid cycles and is suited to trop…

Oil refinery (petroleum refinery) Oil refinery An oil refinery is an industrial complex that converts crude oil into fuels and chemical feedstocks through distillation and refining processes, producing gasoline, diesel, kerosen…

Oil refining Industrial processes and plant systems that transform crude oil into fuels and petrochemical feedstocks, covering key processes, refinery layout, products, history, and environment…

Oil well: purpose, types, drilling methods and operational roles Oil well A comprehensive overview of oil wells: what they are, classifications, drilling techniques (straight, directional, horizontal), production and injection roles, history, and environ…

One-design dinghy A one-design dinghy is a small sailboat built to uniform specifications so racing emphasizes sailor skill rather than design differences. Common in clubs, youth training and regatt…

Oosterscheldekering — the Eastern Scheldt storm surge barrier Oosterscheldekering Major storm surge barrier in the Netherlands, part of the Delta Works, built to protect Zeeland islands from North Sea floods while preserving tidal ecosystems.

Operating environment (computing) Operating environment A computing operating environment is the layer or collection of components that let users interact with an operating system and run applications; this article explains definitions,…

Out-of-order execution in modern processors Out-of-order execution Out-of-order execution is a CPU technique that lets a processor perform ready instructions while waiting for slower operations, improving throughput and hiding memory and pipeline…

Overhead lines (electrical) — systems for supplying power to traction vehicles Overhead lines Overhead lines (OHL or OHLE) are suspended conductors that deliver electric power to trams, trolleybuses and trains. This article explains their parts, operation, history, uses, sa…

Paddle (boat propulsion and mixing tool) Paddle A paddle is a handheld tool for pushing against water or other liquids, used for propelling small craft (canoes, kayaks, SUP) and for stirring or mixing in industrial and domestic…

Pak Beng Dam — Hydropower Project on the Mekong in Laos Pak Beng Dam Pak Beng Dam is a proposed 912 MW mainstream hydroelectric project on the Mekong in Oudomxay Province, Laos. It has raised environmental, social and transboundary concerns and expe…

Pampa Wind Project — proposed 4,000 MW wind farm in the Texas Panhandle Pampa Wind Project Overview of the Pampa Wind Project: proposed scale, developer Mesa Power and T. Boone Pickens, timeline, transmission and financing challenges, outcomes and broader significance fo…

Pantograph — mechanical duplicator and railway current collector Pantograph A pantograph is a mechanical linkage used to copy and scale drawings and, by extension, a roof-mounted current collector on electric trains. This article explains types, operation,…

Parachute A parachute is a fabric device that produces aerodynamic drag to slow descent through air. Used for emergency egress, sport skydiving, military drops and vehicle deceleration, with…

Peaking power plant (peaker): purpose, types, and role in electricity systems Peaking power plant A peaking power plant (peaker) runs only during periods of highest electricity demand. This article explains how peakers operate, their common types, history, uses, and distinction…

Pelletization: process, applications, and industrial significance Pelletization Pelletization is the agglomeration of fine materials into small, typically spherical pellets for easier handling, transport and processing. Common in iron ore, animal feed, biomass…

Perforation: purpose, methods, history and common applications Perforation Perforation is the creation of repeated holes, slits or cuts in a material to allow tearing, airflow, filtration, decoration or function. This article covers types, methods, histor…

Permanent way (railway track structure) Permanent way The permanent way is the installed track structure of a railway: rails, sleepers (ties), fastenings, ballast or slab, formation and drainage that together carry trains and resist l…

Photovoltaics (Solar PV): Principles, Types, and Applications Photovoltaics Photovoltaics convert sunlight into direct current electricity. This article explains how PV systems work, common materials and configurations, history, uses, advantages, and chall…

Pig iron: crude iron produced in blast furnaces Pig iron Pig iron is the high-carbon, brittle intermediate product of smelting iron ore in a blast furnace; it is the raw feedstock for steelmaking and other refined iron products.

Pipe (material): types, sizing, manufacture and uses Pipe (material) A pipe is a rigid hollow cylinder used to convey fluids or protect cables. This article explains materials, sizing and standards, manufacturing methods, applications and distinctio…

Piping and Instrumentation Diagram (P&ID) Piping and instrumentation diagram A P&ID is a detailed schematic showing piping, equipment, valves and instrumentation for a process facility. It guides design, construction, control and safe operation of industria…

Piston (mechanical component) Piston A piston is a sliding element that moves within a cylinder to change volume and transfer force in engines, pumps, compressors and hydraulic systems; it includes rings, skirts and p…

Pitchfork (agricultural implement) Pitchfork Long-handled agricultural fork with several tines used to lift, toss, and move loose materials such as hay, straw, compost and manure; design, history, uses, and care explained.

Pitman arm — steering linkage component Pitman arm A Pitman arm is a steering linkage component that converts rotational motion from a steering gearbox into linear motion for the vehicle's steering linkages. Common in trucks and ve…

Planform (plan view): definition and aircraft wing shapes Planform Planform (plan view) is the orthographic projection of an object onto a horizontal plane; in aviation it denotes an aircraft wing's outline, which strongly influences lift, drag, s…