vacuum tube

(redirected from Microtube)
Also found in: Dictionary, Thesaurus, Encyclopedia.

vac·uum tube

a glass tube from which the air has been removed, containing two or more electrodes, between which passes an electrical current or spark; used in the production of x-rays, or to control circuits. Previously in wide use, the vacuum tube has been supplanted by transistors in electronic circuits.

vacuum tube

A vessel of insulating material (usually glass) that is sealed and has a vacuum sufficiently high to permit the free flow of electrons between the electrodes that extend into the tube from the outside. In England, it is called a vacuum valve.


a space devoid of air or other gas.

vacuum collection
use of a handheld vacuum to recover ectoparasites from the coat of animals.
freed of moisture while in a vacuum. Used in the packaging of food.
vacuum gauge
pressure gauge in a milking machine which indicates the level of vacuum in the system.
vacuum pack
meat or other perishable food is packed in a tightly sealed bag made of copolymers with polyvinyldene chloride and a low vacuum created. A bag made of nylon-polythene laminate is used for bags that are heat-sealed and a high vacuum created. The pack is then frozen for storage or shipment.
vacuum pressure
used as the basis of the modern milking machine; the negative pressure is generated by a vacuum pump and transmitted through metal and rubber pipes to the teat cups and thence to the teats; the continuous basic pressure is what keeps the teat cups on the teats; the periodic fluctuations is what causes the squeezing of the teat walls and the expulsion of the milk from the teats.
vacuum therapy
see cupping.
vacuum tube
many clinical pathology specimens are now collected in evacuated test tubes. A needle connected to the tube through a rubber stopper is passed into a vein. The needle is then connected to the vacuum and the blood or other fluid withdrawn.
References in periodicals archive ?
Conversion from the current equipment to the new microtube may enable the hematology lab to further improve efficiency and potentially reduce specimen labeling errors.
The methodology proposed for the dimensioning of lateral lines, consisting of microtube emitters operated under variable inlet pressure, is characterized by the steps described hereinafter.
Finally, the effects of aspect ratio on pressure drop in microtubes are predicted.
The subgingival samples in the microtube were dispersed using a Vortex and centrifuged (3 minutes at 12,000 rpm).
The PCT MicroTube Adapter Kit includes an ergonomically designed, space-saving Workstation, PCT MicroTubes and MicroCaps, and specialized tools to enable the user to process up to forty-eight samples simultaneously in the company's primary product, the PCT Sample Preparation System ("PCT SPS"), as compared to three currently.
In this study, we describe the synthesis of PANI microtubes and microbelts with thickness in the range of 100-200 nm, diameters in the range of 1-5 [micro]m, and lengths up to several tens and hundreds micrometers by in situ chemical oxidative polymerization of aniline using various amounts of sodium dodecylsulfate (SDS) anionic surfactant.
His lab is a hotbed of microtube technologies because microtubes have more space-related applications than the Mojave has desert.
The hydraulic supply port on the switch valve receives water from the pressurized irrigation main line through a 4-mm microtube, and the use port is connected to the irrigation supply valve.
Labnet International's Ac-cuTherm Microtube Shaking Incubator is a temperature-controlled lab vortexer that uses Peltier technology to rapidly heat and cool precious samples.
The authors' approach is to coat a microtube with a mixture of E-selectin and an antibody.