T-carrier

The T-carrier is a member of the series of carrier systems developed by AT&T Bell Laboratories for digital transmission of multiplexed telephone calls. The first version, the Transmission System 1 (T-1), was introduced in 1962 in the Bell System, and could transmit up to 24 telephone calls simultaneously over a single transmission line of copper wire. Subsequent specifications carried multiples of the basic T1 (1.544 Mbit/s) data rates, such as T2 (6.312 Mbit/s) with 96 channels, T3 (44.736 Mbit/s) with 672 channels, and others.

Transmission System 1

T-1 is a hardware specification for telecommunications trunking. A trunk is a single transmission channel between two points on the network: each point is either a switching center or a node (such as a telephone).

Initially, T-1 trunks were used only to connect major telephone exchanges, via the same twisted pair copper wire that the analog trunks used. If the exchanges were too far apart, a repeater boosted the signal.

Before the digital T-1 system, carrier wave systems such as 12-channel carrier systems worked by frequency division multiplexing; each call was an analog signal. A T-1 trunk could transmit 24 telephone calls at a time, because it used a digital carrier signal called Digital Signal 1 (DS-1). DS-1 is a communications protocol for multiplexing the bitstreams of up to 24 telephone calls, along with two special bits: a framing bit (for frame synchronization) and a maintenance-signaling bit. T-1's maximum data transmission rate is 1.544 megabits per second.

Carrier

Carrier may refer to:

Science and technology

Military

NCIS: New Orleans

NCIS: New Orleans is an American television series combining elements of the military drama and police procedural genres that premiered on Tuesday, September 23, 2014, following its parent series NCIS. The pilot was written by Gary Glasberg. The series' executive producers are Glasberg, Mark Harmon, Jeffrey Lieber, and James Hayman. The series is set and filmed in New Orleans. It is the third member of the NCIS franchise.

On January 12, 2015, NCIS: New Orleans was renewed for a second season, that premiered on September 22, 2015.

On June 19, 2015, Daryl Mitchell and Shalita Grant, who had been recurring cast members, were promoted to series regulars.

Premise

Led by Special Agent in Charge Dwayne Cassius Pride, a former sheriff's deputy, the New Orleans NCIS office handles cases from the Mississippi River to the Texas Panhandle. Living and working out of his office, Pride heads a small team consisting of Special Agent Christopher LaSalle, Special Agent Meredith Brody, and Special Agent Sonja Percy. LaSalle, who was recruited by Pride from the sheriff's office, is a ladies' man who lives and breathes law enforcement; Brody, a transfer from the Great Lakes field office, has worked as a Special Agent Afloat and is keen to leave her past behind as she moves to New Orleans; Percy is a former ATF agent and the team's newest member who wants something more permanent than undercover work. The team are assisted by Dr. Loretta Wade and Sebastian Lund, forensic investigators assigned to the Jefferson Parish Medical Examiners Office, and Patton Plame, an NCIS computer specialist and freelance agent.

Coprecipitation

In chemistry, coprecipitation (CPT) or co-precipitation is the carrying down by a precipitate of substances normally soluble under the conditions employed. Analogously, in medicine, coprecipitation is specifically the precipitation of an unbound "antigen along with an antigen-antibody complex".

Coprecipitation is an important issue in chemical analysis, where it is often undesirable, but in some cases it can be exploited. In gravimetric analysis, which consists on precipitating the analyte and measuring its mass to determine its concentration or purity, coprecipitation is a problem because undesired impurities often coprecipitate with the analyte, resulting in excess mass. This problem can often be mitigated by "digestion" (waiting for the precipitate to equilibrate and form larger, purer particles) or by redissolving the sample and precipitating it again.

On the other hand, in the analysis of trace elements, as is often the case in radiochemistry, coprecipitation is often the only way of separating an element. Since the trace element is too dilute (sometimes less than a part per trillion) to precipitate by conventional means, it is typically coprecipitated with a carrier, a substance that has a similar crystalline structure that can incorporate the desired element. An example is the separation of francium from other radioactive elements by coprecipitating it with caesium salts such as caesium perchlorate. Otto Hahn is credited for promoting the use of coprecipitation in radiochemistry.