Kinematic differences between NLS1 and BLAGN sources

It is well-known that the higher policyclic aromatic hydrocarbon (PAH) abundance, lower black hole mass, higher accretion rate and lower luminosities are among the major characteristics of Narrow-Line Seyfert galaxies (NLS1), when they are compared to Broad line Seyfert galaxies (BLS1). NLS1s may be normal Seyfert galaxies at an early stage of evolution, their black holes may still be growing and/or they could be special for some other reason. In this work we discuss the findings that NLS1s have most of line and continuum luminosities correlated with FWHM(H$\beta$), which may be the trace of their rapid black hole mass grow. BLS1 do not show such trends. Also, PAHs may be destroyed as the black hole grows and the starbursts are removed, for NLS1 objects.Comment: Revisiting narrow-line Seyfert 1 galaxies and their place in the Universe - NLS1 Padov

Extending the Role of Computational Fluid Dynamics in Screw Machines

Previous publications show that computational fluid dynamics (CFD) can be readily used for the flow prediction and analysis of screw compressors. Several case studies are presented in this article to show the scope and applicability of such methods. These include solid–fluid interaction in screw compressors, prediction of flow generated noise in screw machines, cavitation modelling in gear pumps, and flow in multiphase pumps for oil and gas industry. Numerical grids for all these cases were generated by the authors using an in-house grid generator, while the CFD calculations were performed with a variety of commercially available CFD codes. In order to validate the accuracy of the CFD calculations, an extended test programme was carried out using laser Doppler velocimetry to measure the mean and fluctuating velocity distribution in screw compressor flow domains. The measurement results are then compared with the CFD simulations. The results confirm the viability of the developed techniques. It is shown in this publication that the flexibility of the developed method creates further opportunities for a broader use of CFD for analysis of twin screw machines in a range of new applications

Analytical Grid Generation for accurate representation of clearances in CFD for Screw Machines

One of the major factors affecting the performance prediction of twin screw compressors by use of computational fluid dynamics (CFD) is the accuracy with which the leakage gaps are captured by the discretization methods. The accuracy of mapping leakage flows can be improved by increasing the number of grid points on the profile. However, this method faces limitations when it comes to the complex deforming domains of a twin screw compressor because the computational time increases tremendously. In order to address this problem, an analytical grid distribution procedure is formulated that can independently refine the region of high importance for leakage flows in the interlobe space. This paper describes the procedure of analytical grid generation with the refined mesh in the interlobe area and presents a test case to show the influence of the mesh refinement in that area on the performance prediction. It is shown that by using this method, the flow domains in the vicinity of the interlobe gap and the blowhole area are refined which improves accuracy of leakage flow predictions

RXJ 0921+4529: a binary quasar or gravitational lens?

We report the new spectroscopic observations of the gravitational lens RXJ 021+4529 with the multi-mode focal reducer SCORPIO of the SAO RAS 6-m telescope. The new spectral observations were compared with the previously observed spectra of components A and B of RXJ 0921+4529, i.e. the same components observed in different epochs. We found a significant difference in the spectrum between the components that cannot be explained with microlensing and/or spectral variation. We conclude that RXJ 0921+4529 is a binary quasar system, where redshifts of quasars A and B are 1.6535 +/- 0.0005 and 1.6625 +/- 0.0015, respectively.Comment: 6 pages, 5 figures, accepted for publication in The Astrophysical Journal Letter

The Action of Hydrazines upon \u27Thiazolidine-4-carboxylic Acids I. Preparation of D-Penicillamine from D-Benzylpenilloic Acid

In the reaction of phenylhydrazine with n-benzylpenilloic acids (Ia or Ila) n-penicillamine was obtained in high yield and purity. The lack of reactivity of N-acyl derivatives (Ib or Ub) with phenylhydrazine indicated that the above reaction proceeded through the open chain imine tautomer of Ia or Ila (IV). The epim~risation of n-benzylpenilloic acid (Ia and Ha) in aprotic solvents was studied by using PMR spectroscopy

Ring Expansion of Thiazolidine and Nucleophilic Substitution in N-Acyl Derivatives of 6-Thia-3,8-diazabicyclo[3.2.1. ]octan-2-one

Reaction of N3,N8-diacyl 6-thia-3,8-diazabicyclo/3.2. l./octan-2- -one (I) with PC15 or S02Cl2 gave 6-chloro substituted N2,N5-diacyl 7-thia-2,5-diazabicyclo/2.2.2./octan-3-one (II). Treatment of II with water yielded the 6-hydroxy derivative (III) while reaction with methanol gave the 6-methoxy derivative (IV). Under the same reaction conditions the mono N8-acyl derivative (V) gave a mixture of 6-substituted 7-thia-2,5-diazabicyclo/2.2.2./octan-3-one and 4- -su bsti tuted 6-thia-3,8-diazabicyclo/3.2. l ./octan-2-one derivatives (XIV and XV; VI and VII; VIII and IX). It was proposed that ring expansion of thiazolidine and nucleophilic substitution occured vi a the thiiranium ion XIII as a common intermediate

Preparation and lsomerization of 3S-Benzylpenicilloamides

The isomerization of 3S-benzylpenicillobenzylamide in aprotic solvents was studied by using 1H NMR spectroscopy. The lack of isomerization of the N-acetyl derivative of I indicated that the epimerization at C-5 and C-6 positipn2 proceeded through the open chain imine tautomer (III) of I or II. Since the isomerization at the C-6 position occurred after the opening of the thiazolidine ring, it was concluded that isomerization at this centre preceeded through penamaldic acid (IV) as an intermediate. All four isomers· of 3S- benzylpenicillobenzylamide were prepared and isolated as methyl esters (II)