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Page "Chemical vapor deposition" ¶ 28
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hydrogen and reduces
The engine was technically a liquid hydrogen / liquid oxygen design, but dramatically reduces the amount of oxidizer needed to be carried on board by utilising atmospheric oxygen as the spacecraft climbed through the lower atmosphere.
Two water molecules are oxidized by four successive charge-separation reactions by photosystem II to yield a molecule of diatomic oxygen and four hydrogen ions ; the electron yielded in each step is transferred to a redox-active tyrosine residue that then reduces the photoxidized paired-chlorophyll a species called P680 that serves as the primary ( light-driven ) electron donor in the photosystem II reaction center.
* The wave function of the ground state of a hydrogen atom is a spherically-symmetric distribution centred on the nucleus, which is largest at the center and reduces exponentially at larger distances.
Metallic conductivity reduces as hydrogen is absorbed, until at around PdH < sub > 0. 5 </ sub > the solid becomes a semiconductor.
Cytochrome c peroxidase, or CCP is a water-soluble heme-containing enzyme of the peroxidase family that takes reducing equivalents from cytochrome c and reduces hydrogen peroxide to water:
However, for reaching orbital speed, hydrogen is a better fuel, since the high exhaust velocity and hence lower propellant mass reduces the take off weight.
MnSOD reduces superoxide to hydrogen peroxide ( H < sub > 2 </ sub > O < sub > 2 </ sub >), but H < sub > 2 </ sub > O < sub > 2 </ sub > is not increased due to other cellular activity.
Lithium tri-tert-butoxyaluminium hydride, a bulky hydride donor, reduces acyl chlorides to aldehydes, as does the Rosenmund reduction using hydrogen gas over a poisoned palladium catalyst.
Glutathione peroxidase reduces hydrogen peroxide by transferring the energy of the reactive peroxides to a very small sulfur-containing protein called glutathione.
In the large intestine, fructose that has not been adequately absorbed reduces the absorption of water osmotically and is metabolized by colonic bacteria into short chain fatty acids, producing the byproduct gases hydrogen, carbon dioxide and methane.
The mass of the hydrogen tanks needed for compressed hydrogen reduces the fuel economy of the vehicle.
GOx at the surface of the honey reduces atmospheric O < sub > 2 </ sub > to hydrogen peroxide ( H < sub > 2 </ sub > O < sub > 2 </ sub >), which acts as an antimicrobial barrier.
Due to the high temperatures at which MCFCs operate, these fuels are converted to hydrogen within the fuel cell itself by a process called internal reforming, which also reduces cost.
Most rockets that use hydrogen fuel use it in upper stages only, where a low thrust-to-empty-mass ratio can be tolerated and where a hydrogen stage's low total mass reduces the size of the lower stages.
This means that hydrogen accumulates at the cathode and reduces the effectiveness of the cell.
By studying purple sulfur bacteria and green sulfur bacteria he was the first scientist to demonstrate that photosynthesis is a light-dependent redox reaction, in which hydrogen from an oxidizable compound reduces carbon dioxide to cellular materials.
In addition to being an oxidizer and energy carrier, it is loaded with hydrogen and this provides cooling in the gun tube which reduces the erosion rate of the tube metal so more rounds can be fired before refit.
It reduces the content of hydrogen in the aluminium weld, preventing the associated porosity.
A recent description on how the poisons act on the selectivity of the Lindlar catalyst identifies a complementary role of the poisons while Pb reduces the amount of hydrogen content in the bulk of Pd, quinoline blocks the formation of oligomers.
During the LAGB phase, when mass loss reduces the hydrogen envelope's mass to around 10 < sup >− 2 </ sup > M < sub >☉</ sub > for a core mass of 0. 60 M < sub >☉</ sub >, a star will begin to evolve towards the blue side of the Hertzsprung-Russell diagram.

hydrogen and growth
Some species of sorghum can contain levels of hydrogen cyanide, hordenine and nitrates lethal to grazing animals in the early stages of the plant's growth.
The carbon, hydrogen and oxygen that constitute about 96 % of the weight of a typical plant are turned into organic growth by CO < sub > 2 </ sub > in the air and H < sub > 2 </ sub > O from the soil plus dissolved plant nutrients in the soil.
Specifically, hydrogen cyanamide stimulates cell division and growth in dormant plants, causing budbreak when the plant is on the edge of breaking dormancy.
The acid growth theory states that individual cells in the outer layers of the lobes and midrib rapidly move < sup > 1 </ sup > H < sup >+</ sup > ( hydrogen ions ) into their cell walls, lowering the pH and loosening the extracellular components, which allows them to swell rapidly by osmosis, thus elongating and changing the shape of the trap lobe.
Growth rates above 2 micrometres per minute produce polycrystalline silicon, and negative growth rates ( etching ) may occur if too much hydrogen chloride byproduct is present.
Bacterial growth in the reservoir can produce toxic hydrogen sulfide, a source of serious production problems, and block the pores in the rock.
It can produce hydrogen sulfide gas, and forms clear films on growth media.
Anaerobic growth using elemental hydrogen or reduced inorganic sulfur compounds as electron donors and ferric ions as electron acceptors has also been discovered.
Azotobacter can also grow mixotrophically, in a nitrogen-free medium containing mannose ; this growth mode is hydrogen dependent.
A more recent hypothesis, proposed by Proctor ( 1999 ), is that these forests are growing on soils which are highly acidic, such that hydrogen ion toxicity prevents the growth of non-adapted species.

hydrogen and rate
However, the law of mass action is valid only for concerted one-step reactions that proceed through a single transition state and is not valid in general because rate equations do not, in general, follow the stoichiometry of the reaction as Guldberg and Waage had proposed ( see, for example, nucleophilic aliphatic substitution by S < sub > N </ sub > 1 or reaction of hydrogen and bromine to form hydrogen bromide ).
Calcium metal reacts with water, evolving hydrogen gas at a rate rapid enough to be noticeable, but not fast enough at room temperature to generate much heat.
In this way the particularly strong triple bond in nitrogen is weakened and the hydrogen and nitrogen atoms combine faster than would be the case in the gas phase, so the rate of reaction increases.
When in contact with one of the electrodes in a fuel cell, this platinum increases the rate of oxygen reduction to water, either to hydroxide or hydrogen peroxide.
For similar reasons, and also due to the small size of helium atoms, helium's diffusion rate through solids is three times that of air and around 65 % that of hydrogen.
The escape of hydrogen from Earth's atmosphere into space may have occurred at only one percent of the rate previously believed based on revised estimates of the upper atmosphere's temperature.
The dependence of the hydrogen fusion rate on temperature and pressure means that it is only when it is compressed and heated at the surface of the white dwarf to a temperature of some 20 million kelvin that a nuclear fusion reaction occurs ; at these temperatures, hydrogen burns via the CNO cycle.
At $ 0. 03 / kWh, common off-peak high-voltage line rate in the United States, this means hydrogen costs $ 1. 50 a kilogram for the electricity, equivalent to $ 1. 50 a U. S. gallon for gasoline if used in a fuel cell vehicle.
Schmidt realized that these were actually spectral lines of hydrogen redshifted at the rate of 15. 8 percent.
The hydration reaction of CO < sub > 2 </ sub > is generally very slow in the absence of a catalyst, but red blood cells contain carbonic anhydrase, which both increases the reaction rate and dissociates a hydrogen ion ( H < sup >+</ sup >) from the resulting carbonic acid, leaving bicarbonate ( HCO < sub > 3 </ sub >< sup >-</ sup >) dissolved in the blood plasma.
Consequently they have relatively low temperatures in their cores and energy is generated at a slow rate through nuclear fusion of hydrogen into helium by the proton-proton ( PP ) chain mechanism.
While there is no known method to convert matter ( by itself ) completely into energy, an equivalent energy release could theoretically be achieved by fusing approximately 280 kg of hydrogen into helium per second, a rate roughly equivalent to 8. 9 × 10 < sup > 9 </ sup > kg / year.
A cubic km of water contains about 10 < sup > 11 </ sup > kg of hydrogen, and the Earth's oceans contain about 1. 3 × 10 < sup > 9 </ sup > cubic km of water, meaning that this rate of consumption could be sustained over geological time scales.
They estimated that within the expanding universe, hydrogen atoms were being created out of a vacuum at a rate of one atom per cubic meter per 10 < sup > 9 </ sup > years.
In this case, tunneling is important for the hydrogen, as it determines the reaction rate.
In combination with a lower rate of hydrogen consumption due to its low mass, the convection will allow Wolf 359 to remain a main-sequence star for about eight trillion years.
The neutron counting rate is therefore inversely related to the amount of hydrogen in the formation.
Since hydrogen is mostly present in pore fluids ( water, hydrocarbons ) the count rate can be converted into apparent porosity.
* A comparison of 7 non-primate mammals ( mouse, hamster, rat, guinea-pig, rabbit, pig and cow ) showed that the rate of mitochondrial superoxide and hydrogen peroxide production in heart and kidney were inversely correlated with maximum life span
This can lead to a decrease in the reaction rate if the rate-determining step involves breaking a bond between hydrogen and another atom.
Thus, if the reaction changes in rate when protons are replaced by deuteriums, it is reasonable to assume that the breaking of the bond to hydrogen is part of the step which determines the rate.

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