Glossary

Tungsten particles transferred into the weld deposit by occasional touching of the tungsten electrode used in the gas tungsten-arc process to the work or to the molten weld metal. These inclusions are often considered defects that must be removed and the weld repaired prior to final acceptance. Tungsten inclusions may be invisible to the unaided eye, but are readily identified in a radiograph.

(NIST) Determining what parts of a program are being executed the most. A tool that instruments a program to obtain execution frequencies of statements is a tool with this feature.

A suspension of fine particles that obscures light rays but requires many days for sedimentation because of small particle size.

A variation on a chemostat. Whereas a chemostat is designed to constant input of medium, a turbidostat is designed to keep the organisms at a constant concentration. A turbidity sensor measures the concentration of organisms in the culture and adds additional medium when a preset value is exceeded.

A flow field that cannot be described with streamlines in the absolute sense. However, time-averaged streamlines can be defined to describe the average behavior of the flow. In turbulent flow, the inertia stresses dominate over the viscous stresses, leading to small-scale chaotic behavior in the fluid motion.

The state that results from mixing the contents of a fermentor or bioreactor to provide oxygen to the cells. That must be balanced against the shear that causes cell damage and death.

Swollen, distended; referring to a cell that is firm due to water uptake.

A contract where one party takes full responsibility for the construction, commissioning, and delivering of a project in full working order to the owner.

A piece of equipment, process train, or manufacturing plant that is delivered to the customer in a ready-to-run condition, specialized for the customer’s application, with no additional equipment or modifications required.

Also known as “hand over” in the U.K. A formal transfer of custody for a system or unit to another group, department, or operating company.

A collection of pertinent design, construction, vendor, and operational documentation. This collection of documentation is used for the qualification and process validation activity, as well as reference and single source information for the life of any particular system, process, or piece of equipment.NOTE: This term is often used interchangeably with Engineering Turnover Package (ETOP)

A plan for “hand-over” or “transfer of responsibility” of the project.

Total Volatile Hydrocarbon

Time-Weighted Average

The most frequently used exposure guideline term, is the average concentration of a chemical in air over the total exposure time – usually an 8-hour workday (OSHA PELs and ACGIH TLVs), and up to 10 hours in a 40hour workweek (NIOSH Recommended Exposure Limit (RELs).

A pair of thin-diameter insulated wires commonly used in telephone wiring. The wires are twisted around each other to minimize interference from other twisted pairs in the cable. Twisted pairs have less bandwidth than coaxial cable or optical fiber. Abbreviated UTP for Unshielded Twisted Pair. Synonymous: Twisted Wire Pair.

Two-stage tendering is a procedure typically used to achieve an early appointment of a contractor to a lump-sum contract. For the first stage, the objective is to competitively appoint, on the basis of limited information, a preferred contractor for further negotiation.

Separate beds or layers of cation and anion exchange resins. Results in lower purity than mixed-bed deionization but provides higher capacity in terms of throughput.

Thermostatted Well Plate

A Phenolic alpha amino acid; a precursor of the hormones epinephrine, norepinephrine, thyroxine, and triiodothyronine, and of the black pigment melanin.