Technology and the built world

Haldex

Haldex, also known as Haldex AB, is a Swedish manufacturer of brake systems and air suspension for trucks, trailers, and buses, owned by Germany's SAF-HOLLAND since 2023.

Half helmet

A half helmet, sometimes called a pudding bowl, is a motorcycle helmet covering only the top half of the cranium, leaving the face, chin, and jaw exposed.

The half-bridge inverter is the simplest single-phase DC-to-AC converter, using two semiconductor switches and a DC supply split by two capacitors, used in solar inverters, induction cookers, and motor drives.

Half-cut cell

A half-cut cell, also called a half-cell, is a silicon solar cell cut in half by laser, halving its current to cut resistive losses and improve shade tolerance.

Half-Heusler thermoelectric modules

A half-Heusler thermoelectric module is a solid-state generator converting heat into electricity via p-type and n-type half-Heusler alloy legs, suited to medium- and high-temperature waste heat recovery.

Half-Heusler thermoelectrics

Half-Heusler thermoelectrics are ternary intermetallic compounds with the MgAgAs-type crystal structure that convert heat into electricity through the Seebeck effect, led by XNiSn and XCoSb.

Half-power bandwidth method

The half-power bandwidth method is a frequency-domain technique that estimates a vibrating system's damping ratio from the width of its resonance peak, at the 3 dB points.

Half-track

A half-track is a vehicle steered by front wheels and driven by rear caterpillar tracks, best known from the World War II M3 and German Sd.Kfz. 251 carriers.

Half-wave dipole

A half-wave dipole is a center-fed wire antenna cut to nearly half the operating wavelength, resonant at about 73 ohms and first demonstrated by Heinrich Hertz in 1886.

Halfaya oil field

The Halfaya oil field is a supergiant oil field in Missan governorate, southeastern Iraq, holding about 4.1 billion barrels of oil and producing roughly 400,000 barrels per day.

Halfdan oil field

Halfdan is an oil and gas field in the Danish North Sea, discovered in 1998 and on stream since 1999, Denmark's second largest oil and gas field.

Halftone

A halftone, or halftoning, is a printing technique that simulates continuous photographic tone using dots of a single ink color, first available commercially in the 1880s.

Halfweg Pumping Station

Stoomgemaal Halfweg is a steam-driven pumping station in Halfweg, the Netherlands, built in 1852 by the Hoogheemraadschap van Rijnland and now run as a steam-powered museum.

Halibut Oil and Gas Field

Halibut is an offshore oil field in the Gippsland Basin of Bass Strait, southeastern Australia, discovered in August 1967 and produced from the Halibut A platform from March 1970.

Halide perovskite

A halide perovskite is a crystalline semiconductor whose anion sites are halogens such as chlorine, bromine, and iodine, promising for solar cells and light-emitting devices.

Halide perovskite memristors

Halide perovskite memristors are two-terminal resistive switching devices that store data in resistance states, first demonstrated in 2015 and studied for nonvolatile memory and in-memory computing.

Halide segregation

Halide segregation, also called phase segregation, is the light- or bias-driven separation of a mixed-halide perovskite into iodide-rich and bromide-rich domains, a central stability problem for perovskite solar cells.

Halide solid electrolytes

Halide solid electrolytes are lithium or sodium metal halides such as Li₃YCl₆ and Li₃InCl₆ that conduct ions at room temperature, developed as solid electrolytes for all-solid-state batteries.

Halide solid-state electrolyte

A halide solid-state electrolyte is a solid inorganic material, typically a lithium or sodium halide, that conducts alkali-metal ions in all-solid-state batteries instead of flammable liquid electrolytes.

Halifax Explosion

The Halifax Explosion, also called the Halifax disaster, occurred on 6 December 1917 when a French munitions ship collided with another vessel in Halifax Harbor and detonated, killing about 1,600 to 2,000 people.

Halifax Stanfield International Airport

Halifax Stanfield International Airport, formerly Halifax International Airport, is the principal airport of Atlantic Canada, located in Goffs, Nova Scotia, about 35 km from Halifax. It opened in 1960.

Hall effect sensor

A Hall effect sensor, or Hall sensor, is a transducer that converts a magnetic field into an electrical signal via the Hall effect, discovered by Edwin Hall in 1879.

Hall of Mirrors

The Hall of Mirrors (Galerie des Glaces) is the principal gallery of the Palace of Versailles, a 73-meter hall built between 1678 and 1684 with 357 mirrors.

Hall-effect thruster

The Hall-effect thruster, or Hall thruster, is an ion thruster in which trapped electrons ionize xenon, producing thrust for spacecraft, first flown in 1971 on the Soviet Meteor-1-10 satellite.

Hall–Héroult process

The Hall–Héroult process is the industrial electrolytic process that produces nearly all primary aluminum, invented independently by Charles Martin Hall and Paul Héroult in 1886.

Hall–Petch relationship

The Hall–Petch relationship is an empirical relation in materials science: a polycrystalline metal's yield strength increases in proportion to the inverse square root of its average grain size.

Hallam Nuclear Power Facility

The Hallam Nuclear Power Facility was a 75-megawatt demonstration nuclear plant near Hallam, Nebraska, the first sodium-cooled, graphite-moderated reactor to produce electric power, running from 1962 to 1964.

Halley Research Station

Halley Research Station is a British Antarctic Survey base on the Brunt Ice Shelf, Antarctica, whose ozone measurements led to the 1985 ozone hole discovery.

Hallgrímskirkja

Hallgrímskirkja, named for the hymn poet Hallgrímur Pétursson, is a Lutheran parish church in Reykjavík and Iceland's largest church, built from 1945 to 1986 from designs by Guðjón Samúelsson.