Search results
Results From The WOW.Com Content Network
The soil's pH also has a strong effect on the amount of volatilization. Specifically, highly alkaline soils (pH~8.2 or higher) have proven to increase urea hydrolysis. One study has shown complete hydrolysis of urea within two days of application on such soils. In acidic soils (pH 5.2) the urea took twice as long to hydrolyze. [7]
There is a large and growing number of treatment options to make excreta safe and manageable for the intended reuse option. [1] Options include urine diversion and dehydration of feces ( urine-diverting dry toilets ), composting ( composting toilets or external composting processes ), sewage sludge treatment technologies and a range of fecal ...
The Bridgman method is a popular way of producing certain semiconductor crystals such as gallium arsenide, for which the Czochralski method is more difficult. The process can reliably produce single-crystal ingots, but does not necessarily result in uniform properties through the crystal. [1] Diagram of the Bridgman-Stockbarger method
The structure of the molecule of urea is O=C(−NH 2) 2.The urea molecule is planar when in a solid crystal because of sp 2 hybridization of the N orbitals. [8] [9] It is non-planar with C 2 symmetry when in the gas phase [10] or in aqueous solution, [9] with C–N–H and H–N–H bond angles that are intermediate between the trigonal planar angle of 120° and the tetrahedral angle of 109.5°.
The urea crystallizes in a hexagonal crystal structure with about 5.5 to 5.8 Å wide channels. In these channels the n-paraffins are included. If the concentration of n-paraffins in the mixture is too high, the mixture is diluted with a solvent. In general, the reaction proceeds according to the scheme: urea + adduct component -> urea adduct
These can be called urea adducts or if a solvent is involved, a urea solvate, and the process is called urea extraction crystallization. Urea can also be a neutral ligand if it is coordinated to a central metal atom. Urea can form hydrogen bonds to other oxygen and nitrogen atoms in the substance it crystallises with.
S. ureae is an aerobic, motile, spore-forming, Gram-positive coccus, originally isolated in the early 20th century from soil. [1] S. ureae is distinguished by its ability to grow in relatively high concentrations of urea through production of at least one exourease, an enzyme that converts urea to ammonia. [2]
In the absence of plants, urease activity in soil is generally attributed to heterotrophic microorganisms, although it has been demonstrated that some chemoautotrophic ammonium oxidizing bacteria are capable of growth on urea as a sole source of carbon, nitrogen, and energy.