Creeping flow analyses of free surface cavity flows

Two industrially important free surface flows arising in polymer processing and thin film coating applications are modelled as lid-driven cavity problems to which a creeping flow analysis is applied. Each is formulated as a biharmonic boundary-value problem and solved both analytically and numerically. The analytical solutions take the form of a truncated biharmonic series of eigenfunctions for the streamfunction, while numerical results are obtained using a linear, finite-element formulation of the governing equations written in terms of both the streamfunction and vorticity. A key feature of the latter is that problems associated with singularities are alleviated by expanding the solution there in a series of separated eigenfunctions. Both sets of results are found to be in extremely good agreement and reveal distinctive flow transformations that occur as the operating parameters are varied. They also compare well with other published work and experimental observation.     

On the connection between quantum fields and von Neumann algebras of local operators

The relationship between a standard local quantum field and a net of local von Neumann algebras is discussed. Two natural possibilities for such an association are identified, and conditions for these to obtain are found. It is shown that the local net can naturally be so chosen that it satisfies the Special Condition of Duality. The notion of an intrinsically local field operator is introduced, and it is shown that such an operator defines a local net with which the field is locally associated. A regularity condition on the field is formulated, and it is shown that if this condition holds, then there exists a unique local net with which the field is locally associated if and only if the field algebra contains at least one intrinsically local operator. Conditions under which a field and other fields in its Borchers class are associated with the same local net are found, in terms of the regularity condition mentioned.     

Multiple sample amplification and genotyping integrated on a single electronic microarray

We report a novel method that allows simultaneous in situ amplification and then genotyping of single nucleotide polymorphism (SNP) for multiple samples on a single electronic microarray. The locus coding for one of the common inherited thrombosis risk factors, Factor V Leiden (FVL), was chosen as a model system for SNP analysis. This method combines strand displacement amplification (SDA) with electrophoretic movement and concentration of DNA on electronic microarrays to provide a single platform for DNA amplification and analysis. The method includes: electronic anchoring of allele-specific SDA amplifiable primers (APs) and a nonamplifiable primer (NAP) to different electrodes, electronic hybridization of genomic DNA from different samples to those primers, in situ amplification of target DNA, and genotyping of FVL. Compared to previous anchored SDA methods, the addition of a NAP improves detection signals by at least 20-fold. The sensitivity of this method is dependent on the amplification time. Using this method, nine different genomic DNA samples with known FVL genotypes were amplified and correctly genotyped on a single electronic microarray without any contamination between samples. The present method could streamline development of nucleic acid-based assays in applications of molecular diagnostic, point-of-care testing, and forensic detection, which often require the capability to analyze multiple samples efficiently.     

Mass spectral fragmentation pattern of 2,3-dimethyl- and 2-methyl-3-phenyl-4-arylazoisoxazol-5-ones

2,3-Dimethyl-4-arylazoisoxazol-5-ones and 2-methyl-3-phenyl-4-aryiazoisoxazol-5-ones undergo considerable fragmentation on electron impact. The base peaks in the mass spectra are at mass 56 and 118 respectively attributed to the N-methylacetonitrile cation and the N-methylbenzonitrile cation.     

Reaction of metallo S-alkyl N-cyanodithioiminocarbonates and alkyl N-cyanocarbamates with hydrazine. A novel preparation of 5-amino-3-mercapto-1,2,4-triazole

Metal salts of S-alkyl-N-cyanodithioiminocarbonates 7 react as electrophiles with hydrazine hydrate to form 5-amino-3-mercapto-1H-1,2,4-triazole 1 . The novel 4-cyanothiosemicarbazide 9 is proposed as the intermediate which cyclizes to the aromatic triazole. The rate determining step is addition of hydrazine to the iminocarbonate and is second order. Other nucleophiles such as substituted hydrazines and amines failed to react. Exchange of either or both sulfurs with oxygen leads to decomposition or mixtures of products.     

Mass spectral fragmentation pattern of 2,2′-Bipyridyls. Part X. trans-1,2-Di-(2-pyridyl)ethylene

The base peak in the mass spectrum of trans-1,2-di-(2-pyridyl)ethylene is due to the M-1 ion. A major fragmentation route involves loss of HCN from the M-1 ion. Another important pathway involves rupture of one of the bonds linking a pyridine ring with the central CH?CH group.     

Mass spectral fragmentation pattern of 4,4′-bipyridines. Part II. 4,4′-oxybispyridine and 4,4′-thiobispyridine

The mass spectra of 4,4′-oxybispyridine and 4,4′-thiobispyridine are reported. In the former the base peak is due to the molecular ion and the fragmentation routes involve loss of H, CO, HCN, C₂H₂N and C_sHO from the molecular ion as well as rupture of the central bonds. In the latter the base peak is also due to the molecular ion and the fragmentation routes involve loss of H, CS, S, HCN and C₂HS as well as central bond rupture.