Catalysis

Catalysis (/kəˈtælᵻsᵻs/) is the increase in the rate of a chemical reaction due to the participation of an additional substance called a catalyst (/ˈkætəlᵻst/). With a catalyst, reactions occur faster and require less activation energy. Because catalysts are not consumed in the catalyzed reaction, they can continue to catalyze the reaction of further quantities of reactant. Often only tiny amounts are required.

Technical perspective

In the presence of a catalyst, less free energy is required to reach the transition state, but the total free energy from reactants to products does not change. A catalyst may participate in multiple chemical transformations. The effect of a catalyst may vary due to the presence of other substances known as inhibitors or poisons (which reduce the catalytic activity) or promoters (which increase the activity). The opposite of a catalyst, a substance that reduces the rate of a reaction, is an inhibitor.

Catalyzed reactions have a lower activation energy (rate-limiting free energy of activation) than the corresponding uncatalyzed reaction, resulting in a higher reaction rate at the same temperature and for the same reactant concentrations. However, the detailed mechanics of catalysis is complex. Catalysts may affect the reaction environment favorably, or bind to the reagents to polarize bonds, e.g. acid catalysts for reactions of carbonyl compounds, or form specific intermediates that are not produced naturally, such as osmate esters in osmium tetroxide-catalyzed dihydroxylation of alkenes, or cause dissociation of reagents to reactive forms, such as chemisorbed hydrogen in catalytic hydrogenation.

Catalyst (Prototype album)

Catalyst is the third studio album by heavy metal band Prototype. The album was released on September 11, 2012 by Nightmare Records, following up from their 2006 album Continuum.

Track listing

Personnel

Catalyst (think tank)

Catalyst (later Catalyst Forum) was an independent left wing think tank based in London, United Kingdom, set up in 1998 to promote policies directed to the redistribution of power, wealth and opportunity. Though not aligned to any political party, it was generally sympathetic to the Labour Movement and described itself as "an organisation of the left".

The organisation was founded at the high point of Tony Blair's modernisation of the Labour Party and struggled to attract funding, especially from the trades unions who had originally been expected to be the most sympathetic to its redistributionist platform. Trades unions, concerned at further exclusion from power either by the electorate or the new Labour Party leadership, took a sharp turn away from too deep an association with the Left at this time and only begun in 2005 and 2006 to develop an increased if cautious interest in left-wing thought as a new generation of activist trades union leaders has emerged.

Former right wing but egalitarian Deputy Leader of the Labour Party, Roy Hattersley, was an early supporter, as was John Edmonds, General Secretary of the GMB Union.

Unity

Unity may refer to:

Education

Music

Media and entertainment

Unity (ISS module)

The Unity connecting module was the first U.S.-built component of the International Space Station. It is cylindrical in shape, with six berthing locations (forward, aft, port, starboard, zenith, and nadir) facilitating connections to other modules. Unity measures 4.57 metres (15.0 ft) in diameter, is 5.47 metres (17.9 ft) long, and was built for NASA by Boeing in a manufacturing facility at the Marshall Space Flight Center in Huntsville, Alabama. Sometimes referred to as Node 1, Unity was the first of the three connecting modules; the other two are Harmony and Tranquility.

Launch and initial berthing

Unity was carried into orbit as the primary cargo of the Space Shuttle Endeavour on STS-88, the first Space Shuttle mission dedicated to assembly of the station. On December 6, 1998, the STS-88 crew mated the aft berthing port of Unity with the forward hatch of the already orbiting Zarya module. (Zarya was a mixed Russian-US funded and Russian-built component launched earlier aboard a Russian Proton rocket from Baikonur, Kazakhstan.) This was the first connection made between two station modules.

Unity (Star Trek: Voyager)

"Unity" is the 17th episode of the third season of the American science fiction television series Star Trek: Voyager, the 59th episode overall. The episode first aired on the UPN network on February 12, 1997, as part of sweeps week. It was written by producer Kenneth Biller, and is the second episode to be directed by cast member Robert Duncan McNeill. It marked the first appearance of the Borg in Voyager.

Set in the 24th century, the series follows the adventures of the Starfleet and Maquis crew of the starship USS Voyager after they were stranded in the Delta Quadrant far from the rest of the Federation. In this episode, while on an away mission, Chakotay is taken in by a group of former Borg who seek help from the crew of Voyager to reactivate their neural link. The ex-Borg force Chakotay to reactivate a Borg cube (a large Borg spaceship), but, in their new-found "Co-operative", the ex-Borg make the cube self-destruct, saving Voyager.

Biller was influenced by the story of the Tower of Babel in writing the episode, and also considered the dissolution of the Soviet Union to be an influence. The crew re-used the make-up and costumes of the Borg designed for the film Star Trek: First Contact, but sets were not re-used. A new fully computer generated Borg cube was created for "Unity", and the storyline of the episode was intended as a hint to those in the later two-part episode "Scorpion". According to Nielsen ratings, it received a 5.4/8 percent share of the audience on first broadcast. "Unity" was received positively by critics, with praise directed at McNeill's direction as well as Biller's plot.