Hydrogen (disambiguation)

Hydrogen is a chemical element.

Hydrogen may also refer to:

See also

Isotopes of hydrogen

Hydrogen (H) (relative atomic mass: 1.00794) has three naturally occurring isotopes, sometimes denoted ¹H, ²H, and ³H. The first two of these are stable while ³H has a half-life of 12.32 years. All heavier isotopes are synthetic and have a half-life less than one zeptosecond (10⁻²¹ second). Of these, ⁵H is the most stable, and ⁷H is the least.

Hydrogen is the only element whose isotopes have different names that are in common use today. The ²H (or hydrogen-2) isotope is usually called deuterium, while the ³H (or hydrogen-3) isotope is usually called tritium. The symbols D and T (instead of ²H and ³H) are sometimes used for deuterium and tritium. The IUPAC states in the 2005 Red Book that while the use of D and T is common, it is not preferred because it can cause problems in the alphabetic sorting of chemical formulae. The ordinary isotope of hydrogen, with no neutrons, is sometimes called "protium". (During the early study of radioactivity, some other heavy radioactive isotopes were given names, but such names are rarely used today.)

GM HydroGen4

HydroGen4is the successor of the fuel cell vehicle HydroGen3, developed by General Motors/Opel and presented in 2007 at the IAA in Frankfurt. It is expected that automotive hydrogen technology, such as the type featured in the HydroGen4, may enter the early commercialization phase in the 2015 - 2020 time frame.

Specification

The vehicle is based on the Chevrolet Equinox and has a GM fuel cell with 440 cells and an output of 93 kW. The hybrid powertrain also contains a nickel-metal-hydride battery with an energy content of 1.8 kWh/35 kW and a three-phase synchronous motor with 73 kW continuous power and 320 Nm of torque. The peak power of the engine is 94 kW. The hydrogen tanks at 700 Bar (10000 PSI) pressure contain 4.2 kilograms of hydrogen, which last about 320 kilometers (200 mi). The maximum speed is 160 km/h with an acceleration from 0 to 100 km/h in 12 seconds. The HydroGen4 is produced in a batch of 170 pcs from which 10 for the Clean Energy Partnership project in Berlin.

Split

Split(s) or The Split may refer to:

Places

Music

Games

Sports and dance

Splitting lemma

In mathematics, and more specifically in homological algebra, the splitting lemma states that in any abelian category, the following statements for a short exact sequence are equivalent.

Given a short exact sequence with maps q and r:

one writes the additional arrows t and u for maps that may not exist:

Then the following statements are equivalent:

The short exact sequence is called split if any of the above statements hold.

(The word "map" refers to morphisms in the abelian category we are working in, not mappings between sets.)

It allows one to refine the first isomorphism theorem:

the first isomorphism theorem states that in the above short exact sequence, (i.e. "C" isomorphic to the coimage of "r" or cokernel of "q")

if the sequence splits, then , and the first isomorphism theorem is just the projection onto C.

It is a categorical generalization of the rank–nullity theorem (in the form ) in linear algebra.

Proof

First, to show that (3) implies both (1) and (2), we assume (3) and take as t the natural projection of the direct sum onto A, and take as u the natural injection of C into the direct sum.

Split (Lush album)

Split is the second album by British shoegazing act Lush, released on 4AD on June 13, 1994 in the UK and a day later in the US. Two singles were released from the album: "Desire Lines" and "Hypocrite," both released on May 30, 1994. Split was reissued by 4AD on CD in July 2001.

Reception

Select gave the album a negative review of two out of five. The review described the album as "mid-paced stuff, fitting between melancholy and listlessness." "There's nothing wrong with a dose of heavyweight introspection per se. But a pretty deft touch is needed to translate it movingly to the recording studio."

Andy Kellman, writing for Allmusic, was far more positive, giving the album 4.5 stars out of five: "Split touches on most forms of emotional turbulence. A legitimizing stunner, the record prevented the band from being lost amidst the bunker of form-over-function dream pop bands. Split shattered every negative aspect of those failed acts with flying colors. A fantastic record within any realm."