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Synthesis and crystal structures of 5-amino-1-(2-hydroxyethyl)imidazole-4-carboxamide and 5-amino-1-(2-chloroethyl)-4-cyanoimidazole (1999)

Banerjee, T. ; Chaudhuri, S. ; Moore, M. ; [et al.]

Springer

Journal of chemical crystallography 29 (1999), S. 1281-1286

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ISSN: 1572-8854

Keywords: amino-imidazoles ; intramolecular hydrogen bonds

Source: Springer Online Journal Archives 1860-2000

Topics: Geosciences , Physics

Notes: Abstract Both 5-amino-1-(2-hydroxyethyl)imidazole-4-carboxamide (AHIC) and 5-amino-1-(2-chloroethyl)-4-cyanoimidazole (ACCI) have been synthesized and crystallized in the monoclinic space group P21/c, Z = 4, with a = 8.420(2), b = 9.759(2), c = 10.583(2) Å, β = 111.80(2)° for AHIC and a = 6.139(1), b = 8.522(2), c = 15.156(3) Å, β = 96.71(2)° for ACCI. Differences in the molecular geometries of the two compounds are attributed to the differences in the substituents at the 1- and 4-positions of the imidazole ring. The molecular conformation of AHIC is stabilized by intramolecular hydrogen bonding between the 5-amino and the vicinal carboxamide moiety, resulting in an extended planar structural pattern. The presence of the cyano group in the 4-position of ACCI prevents the formation of such an intramolecular hydrogen bond. Both the crystal structures are stabilized by networks of intermolecular hydrogen bonds.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1023/A:1009561108403

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Space-time finite element computation of compressible flows between moving components (1995)

Wren, G. P. ; Ray, S. E. ; Aliabadi, S. K. ; [et al.]

Chichester : Wiley-Blackwell

International Journal for Numerical Methods in Fluids 21 (1995), S. 981-991

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ISSN: 0271-2091

Keywords: finite elements ; compressible flow ; space-time formulation ; moving components ; Engineering ; Engineering General

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Notes: A numerical simulation capability for the injector flow of a regenerative liquid propellant gun (RLPG) is presented. The problem involves fairly complex geometries and two pistons in relative motion; therefore a stabilized space-time finite element formulation developed earlier and capable of handling flows with moving mechanical components is used. In addition to the specifics of the numerical method, its application to a 30 mm RLPG test firing is discussed. The computational data from the simulation of this test case are interpreted to provide information on flow characteristics, with emphasis on the tendency of the flow to separate from the injection orifice boundary of the test problem. In addition, the computations provided insight into the behaviour of the flow entering the combustion chamber.

Additional Material: 8 Ill.