147 research outputs found
Random routing scheme with misleading dead ends
A new method of sink location security in a Wireless Sensor Network is proposed. In the proposed scheme, all the node addresses are encrypted and an attacker cannot determine the real sink address by capturing the packets and analyzing its contents for the final destination. The main contribution of our proposed method is to use random routing scheme with misleading dead ends. This provides security against traffic analysis attack
A bilateral shear layer between two parallel Couette flows
We consider a shear layer of a kind not previously studied to our knowledge.
Contrary to the classical free shear layer, the width of the shear zone does
not vary in the streamwise direction but rather exhibits a lateral variation.
Based on some simplifying assumptions, an analytic solution has been derived
for the new shear layer. These assumptions have been justified by a comparison
with numerical solutions of the full Navier-Stokes equations, which accord with
the analytical solution to better than 1% in the entire domain. An explicit
formula is found for the width of the shear zone as a function of wall-normal
coordinate. This width is independent of wall velocities in the laminar regime.
Preliminary results for a co-current laminar-turbulent shear layer in the same
geometry are also presented. Shear-layer instabilities were then developed and
resulted in an unsteady mixing zone at the interface between the two co-current
streams.Comment: 6 pages, 7 figures. Accepted for publication in Phys. Rev.
Dimethyl 4-(3-hydroxyphenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate
The 1,4-dihydropyridine ring in the title compound, C17H19NO5, has a flattened-boat conformation, and the benzene ring is almost orthogonal to it [dihedral angle = 82.98 (12)°]. The hydroxy group is disordered over two positions in a 0.780 (4):0.220 (4) ratio. In the crystal, hydrogen-bonding interactions of the type Na—H⋯Oc and Oh—H⋯Oc (a = amine, c = carbonyl and h = hydroxy) link the molecules into a three-dimensional network
(2E)-3-(4-Bromophenyl)-1-(2-methyl-4-phenyl-3-quinolyl)prop-2-en-1-one
The conformation about the ethene bond [1.316 (3) Å] in the title compound, C25H18BrNO, is E. The quinoline ring forms dihedral angles of 67.21 (10) and 71.68 (10)° with the benzene and bromo-substituted benzene rings, respectively. Highlighting the non-planar arrangement of aromatic rings, the dihedral angle formed between the benzene rings is 58.57 (12)°
Ethyl 4-(3-hydroxyphenyl)-2,7,7-trimethyl-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate
In the molecular structure of the title compound, C21H25NO4, the dihydropyridine ring adopts a flattened boat conformation while the cyclohexenone ring is in an envelope conformation. In the crystal structure, molecules are linked into a two-dimensional network parallel to (10) by N—H⋯O and O—H⋯O hydrogen bonds. The network is generated by R
4
4(30) and R
4
4(34) graph-set motifs
Tris(methyl 3-oxobutanoato-κ2 O,O′)aluminium(III)
In the title compound, [Al(C5H7O3)3], three acac-type ligands (methyl 3-oxobutanoate anions) chelate to the aluminium(III) cation in a slightly distorted AlO6 octahedral coordination geometry. Electron delocalization occurs within the chelating rings
Ethyl 2-acetyl-3-(4-chloroanilino)butanoate
The title compound, C14H18ClNO3, adopts an extended conformation, with all of the main chain torsion angles associated with the ester and amino groups trans. In the crystal, inversion dimers linked by pairs of N—H⋯O hydrogen bonds are observed
3-Ethyl-4-methyl-1H-pyrazol-2-ium-5-olate
The title compound, C6H10N2O, is a zwitterionic pyrazole derivative. The crystal packing is predominantly governed by a three-center iminium–amine N+—H⋯O−⋯H—N interaction, leading to an undulating sheet-like structure lying parallel to (100)
4-(4-Chlorophenyl)-N-[(E)-4-(dimethylamino)benzylidene]-1,3-thiazol-2-amine
The title compound, C18H16ClN3S, adopts an extended molecular structure. The thiazole ring is inclined by 9.2 (1) and 15.3 (1)° with respect to the chlorophenyl and 4-(dimethylamino)phenyl rings, respectively, while the benzene ring planes make an angle of 19.0 (1)°. A weak intermolecular C—H⋯π contact is observed in the crystal structure
1,1′-(p-Phenylenedimethylene)dipiperidin-4-one
In the molecule of the title compound, C18H24N2O2, the piperidine rings are in chair conformations. The crystal structure is stabilized by intermolecular C—H⋯O hydrogen bonding. There are neither C—H⋯π nor π–π interactions in the structure
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