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SLSA (framework)
SLSA (pronounced "salsa"), short for Supply-chain Levels for Software Artifacts, is an OpenSSF security framework defining incremental supply chain security levels, with a Build Track of three levels and a Source Track added in 2025.
Sludge anaerobic fermentation
Sludge anaerobic fermentation is a biological wastewater treatment process that converts organic matter in waste sludge into volatile fatty acids, used as a renewable carbon source.
Sludge thickening
Sludge thickening is a sludge treatment step that removes water from wastewater sludge to reduce volume and lower downstream costs, using gravity, dissolved air flotation, centrifuges, or gravity belts.
Slug (coin)
A slug is a piece of metal, such as a washer or token, substituted for a genuine coin in machines like payphones and parking meters to get service without paying.
Slug catcher
A slug catcher is a vessel or pipe installation at the end of a multiphase gas pipeline that catches liquid slugs and feeds gas and liquid to processing at manageable rates.
Sluice
A sluice, also called a knife gate or stopgate, is a channel or gated opening that controls water flow in canals, dams, locks, and flood defenses.
Slurm
Slurm is an open-source, highly scalable cluster management and job scheduling system for Linux clusters, begun at Lawrence Livermore National Laboratory in 2002 and now powering a majority of TOP500 supercomputers.
Slurm Workload Manager
Slurm is an open source workload manager and job scheduler for Linux clusters, begun at Lawrence Livermore National Laboratory in 2002 and used on most top supercomputers.
Slurry pump
A slurry pump, also known as a lined pump or dredge pump, is a heavy-duty centrifugal pump that transports abrasive slurries in mining and dredging.
Slurry seal
Slurry seal is a low-cost pavement preservation treatment of emulsified asphalt, water, fine aggregate, and mineral filler, spread thin to seal cracks and waterproof surfaces.
Slurry shield
A slurry shield is a tunnel boring machine that supports the tunnel face with pressurized bentonite slurry, best suited to coarse sand and gravel with high groundwater pressure.
Slurry trench cut-off wall
A slurry trench cut-off wall is a vertical underground barrier built by excavating a bentonite-stabilized trench and filling it with low-permeability material to block groundwater flow and contain contaminants.
Slurry tunnel boring machine
A slurry tunnel boring machine, commonly called a mixshield, is a TBM that supports the tunnel face with pressurized bentonite slurry, chosen where groundwater must be held under tight pressure control.
Slush hydrogen
Slush hydrogen (SLH2) is a mixture of solid hydrogen particles in subcooled liquid hydrogen, studied as a denser rocket propellant with about 16% higher density than liquid hydrogen.
SLV (Indian rocket)
The SLV-3 was India's first satellite launch vehicle, an all-solid four-stage rocket developed by ISRO, led by A. P. J. Abdul Kalam and flown four times between 1979 and 1983.
SM Mall of Asia
SM Mall of Asia is a large shopping mall in Pasay City, Philippines, opened in 2006 on reclaimed Manila Bay land and one of the world's largest malls.
SM Nuvali
SM Nuvali, also known as SM City Nuvali, is a shopping mall by SM Prime Holdings in Santa Rosa, Laguna, Philippines, set to open in November 2026.
SM-6
The SM-6 (RIM-174 Standard Missile 6, also called ERAM) is a Raytheon-built, ship-launched US Navy surface-to-air missile, in service since 2013, that also performs anti-surface and ballistic missile defense missions.
SM-65 Atlas
The SM-65 Atlas, also known as the Atlas ICBM, was the United States Air Force's first operational intercontinental ballistic missile, deployed from 1959 to 1966.
SMA connector
The SMA connector (SubMiniature version A) is a semi-precision 50-ohm coaxial RF connector with threaded coupling, designed in 1958 and the default microwave connector for test equipment, antennas, and telecom.
SMA Solar Technology
SMA Solar Technology is a German company founded in 1981 and headquartered in Niestetal near Kassel that develops and sells photovoltaic inverters and energy-management systems worldwide.
SMACH (robotics)
SMACH, short for State MACHine, is a Python task-level execution framework for composing complex robot behaviors as hierarchical, concurrent state machines, with integration for ROS.
Small caps
Small caps, also called small capitals, are capital letterforms drawn at roughly the x-height so they blend into lowercase text; true ones are specially drawn, not merely shrunken capitals.
Small cell
A small cell is a low-powered wireless base station covering a small area, used to extend coverage and add capacity where macro cell networks are weak or overloaded.
Small files problem
Small files problem: performance degradation in HDFS and lakehouse tables (Delta Lake, Apache Iceberg) when many tiny files overwhelm NameNode metadata, add per-file overhead, and require compaction (OPTIMIZE, auto compaction) into larger files.
Small Form-factor Pluggable
Small Form-factor Pluggable, also known as Mini-GBIC or SFP, is a hot-swappable transceiver module that plugs into network switches and routers to link their circuitry with fiber-optic or copper networks.
Small modular reactor
A small modular reactor, or SMR, is a nuclear reactor of up to 300 MWe whose modules are fabricated in a factory and shipped to site for assembly.
Small Refinery Exemption
A Small Refinery Exemption is a US EPA waiver under the Clean Air Act freeing a small refinery from Renewable Fuel Standard obligations for disproportionate economic hardship.
Small satellite
A small satellite, or SmallSat, is an artificial satellite commonly defined as having a wet mass below 500 kilograms, built at a fraction of conventional spacecraft cost.
Small Sports Car SC01 (小跑车SC01)
The Small Sports Car SC01 (小跑车SC01) is a lightweight two-seat electric sports car developed by Tianjin startup TGAT and built by JMEV, which launched it in China as the JMEV 01 in April 2025.