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Hot cracking
Hot cracking is the formation of intergranular cracks in a metal during solidification or at elevated temperatures, when liquid films along grain boundaries cannot withstand strain; it appears in welding, casting, and additive manufacturing.
Hot extrusion
Hot extrusion is a bulk metal forming process in which a heated billet is forced through a shaped die, producing long parts of constant cross-section, solid or hollow.
Hot forging
Hot forging is a metal forming process in which metal is compressed above its recrystallization temperature, above 1,000 °C for steel, so it does not strain-harden.
Hot in-place recycling
Hot in-place recycling is a pavement rehabilitation method that softens existing asphalt with heat and repaves it on site, minimizing new materials and correcting surface distresses like cracks and ruts.
Hot isostatic pressing
Hot isostatic pressing (HIP) is a materials processing method that applies high temperature and uniform gas pressure to consolidate powders and close internal porosity in cast and 3D-printed parts.
Hot melt extrusion
Hot melt extrusion (HME) is a solvent-free pharmaceutical process that melts a drug with a thermoplastic polymer and forces it through a die, forming amorphous solid dispersions and shaped dosage forms.
Hot Metal Bridge
The Hot Metal Bridge is a pair of truss bridges crossing the Monongahela River in Pittsburgh, built to carry molten iron for Jones & Laughlin Steel.
Hot metal typesetting
Hot metal typesetting, also called mechanical typesetting or hot type, sets text for letterpress printing by injecting molten type metal into molds; it dominated from the 1880s to the 1970s.
Hot or Not
Hot or Not, originally Am I Hot or Not, was a website launched in 2000 where users uploaded photos and visitors rated their attractiveness from 1 to 10.
Hot pressing
Hot pressing is a powder metallurgy method that applies heat and uniaxial pressure simultaneously in a die, densifying powder into a solid component in one operation.
Hot rod
A hot rod, sometimes called a street rod, is an automobile stripped down and modified to go faster and handle better, classically a pre-World War II American car.
Hot rolling
Hot rolling is a metalworking process in which metal, most commonly steel, is rolled above its recrystallization temperature so it deforms plastically without strain-hardening, typically the first forming step after casting.
Hot Shots!
Hot Shots! is a 1991 American parody war film directed by Jim Abrahams and starring Charlie Sheen, Valeria Golino, and Lloyd Bridges, spoofing Top Gun.
Hot spot in photovoltaic modules
A hot spot in a photovoltaic module is localized excessive heating that forms when shading or a cell defect forces a solar cell into reverse bias, damaging the module.
Hot stamping
Hot stamping, also called press hardening, is a sheet metal forming process that heats a steel blank and quenches it in the die, producing very strong parts.
Hot swapping
Hot swapping is the replacement or addition of components, such as disk drives, power supplies, or circuit boards, to a running system without shutting it down, keeping services available.
Hot tapping
Hot tapping, also called pressure tapping, is a technique for making a new branch connection into a pressurized pipe while it stays in service, avoiding shutdowns and methane venting.
Hot tub
A hot tub, also called a whirlpool bath, is a large tub of heated water, typically 38–40 °C, fitted with jets for relaxation or hydrotherapy.
Hot water bottle
A hot water bottle is a sealed rubber or PVC container filled with hot water, used to warm a bed or ease pain; the modern type dates to 1903.
Hot water extraction
Hot water extraction, also called autohydrolysis or liquid hot water pretreatment (LHW), uses heated pressurized water alone to dissolve hemicelluloses from lignocellulosic biomass, needing no added chemicals or neutralization.
Hot water pretreatment
Hot water pretreatment, also called liquid hot water (LHW) pretreatment, cooks lignocellulosic biomass in pressurized water at 160–240 °C to dissolve hemicellulose and make cellulose accessible for bioethanol production.
Hot-carrier solar cell
A hot-carrier solar cell is a proposed photovoltaic device that extracts photoexcited carriers before they cool, proposed by Ross and Nozik in 1982 with a theoretical efficiency of 66%.
Hot-dip galvanization
Hot-dip galvanization, also called hot-dip galvanizing, is the most common method of protecting steel from corrosion, immersing it in a molten zinc bath at around 450 °C.
Hot-melt adhesive
Hot-melt adhesive, also known as hot glue or hotmelt, is a solvent-free thermoplastic adhesive applied molten at 120–180 °C that bonds as it cools, widely used in packaging and bookbinding.
HOTAS
HOTAS (Hands On Throttle And Stick) is a cockpit control concept that places vital switches on the throttle and control stick so pilots never let go, first used operationally in the early 1960s.
Hotchkiss M1909 Benét–Mercié machine gun
The Hotchkiss M1909 Benét–Mercié, also called the Hotchkiss Portative, was a French light machine gun designed by Laurence Benét and Henri Mercié and adopted in 1909 by France, Britain, and the United States.
Hotel Astoria (Saint Petersburg)
The Hotel Astoria is a historic five-star hotel on St Isaac's Square in Saint Petersburg, Russia, built in 1911–1912 by Fyodor Lidval and run by Rocco Forte Hotels since 1997.
Hôtel Biron
The Hôtel Biron is an eighteenth-century private mansion in Paris, built for financier Abraham Peyrenc de Moras and known today as the building housing the Musée Rodin.
Hotel Chelsea
The Hotel Chelsea, also known as The Chelsea, is a historic Manhattan hotel opened in 1884, best known as an artists' colony for residents like Bob Dylan and Patti Smith.
Hôtel de Paris
The Hôtel de Paris is a luxury palace hotel on the Place du Casino in Monte-Carlo, Monaco, opened in 1864 by François Blanc beside the Casino de Monte-Carlo.