Spray characteristics of a gasoline direct injector injector with short durations of injection

The sprays into atmosphere from a GDI injector were visualised and the velocity and droplet characteristics measured at an injection pressure of 50 bar and at different injection durations, with emphasis on short injection periods. The images show that the initial and closing delay times were 0.225 and 0.2 ms, respectively, and that the cone angle increased with injection duration to a constant value of 62° at 0.5 ms. They also revealed large droplets ahead of the main spray with its smaller droplets. An injection duration of 0.15 ms led to fuel leaving the injector with little atomisation, but a 30% increase led to the formation of the cone, which was present for times greater than 0.5 ms. The poor atomisation associated with short injection durations and the initial phase of longer injections, was due to low swirl velocities. The droplet velocities were higher in the initial phase of injection than in the main phase, with values up to 50 m/s. The Sauter mean diameters of the initial and main-spray droplets were approximately 55 and 35 μm respectively and with a tendency to decrease with time from the start of injection. Received: 20 October 2000/Accepted: 30 March 2001     

Synthesis and Antitumor Evaluation of Some New Fused and Binary Pyridines

Syntheses of some new heterocyclic compounds containing pyridone, thioxopyridine, halogenated‐pyridine‐carbonitriles, pyrazolopyridine, and pyridine derivatives were achieved. Besides, a modified synthetic method for the synthesis of 2‐chloro‐4,6‐dimethyl‐nicotinonitrile ( 3 ) through the reaction of acetylacetone and malononitrile as starting materials was implemented. The reaction of 2‐chloronicotinonitrile 3 with substituted amines to 2‐aminonicotinonitrile were also investigated. Fused or binary pyridines were tested for cytotoxicity against well‐known established model Ehrlich ascites cells in vitro. Compound 13 exhibited a high antitumor activity compared with 5‐fluorouracil.     

IMPROVEMENT OF THE SEMI-ANALYTICAL METHOD, FOR DETERMINING THE GEOMETRICALLY NON-LINEAR RESPONSE OF THIN STRAIGHT STRUCTURES: PART II—FIRST AND SECOND NON-LINEAR MODE SHAPES OF FULLY CLAMPED RECTANGULAR PLATES

In a previous series of papers, a semi-analytical model based on Hamilton's principle and spectral analysis has been developed for geometrically non-linear free vibrations occurring at large displacement amplitudes of clamped-clamped beams and fully clamped rectangular homogeneous and composite plates. In Part I of this series of papers, concerned with geometrically non-linear free and forced vibrations of various beams, a practical simple “multi-mode theory”, based on the linearization of the non-linear algebraic equations, written in the modal basis, in the neighbourhood of each resonance has been developed. Simple explicit formulae, ready and easy to use for analytical or engineering purposes have been derived, which allows direct calculation of the basic function contributions to the first three non-linear mode shapes of the beams considered. Also, various possible truncations of the series expansion defining the first non-linear mode shape have been considered and compared with the complete solution, which showed that an increasing number of basic functions has to be used, corresponding to increasingly sized intervals of vibration amplitudes; starting from use of only one function, i.e., the first linear mode shape, corresponding to very small amplitudes, for which the linear theory is still valid, and ending by the complete series, involving six functions, corresponding to maximum vibration amplitudes at the beam middle point up to once the beam thickness. For higher amplitudes, a complementary second formulation has been developed, leading to reproduction of the known results via the solution of reduced linear systems of five equations and five unknowns. The purpose of this paper is to extend and adapt the approach described above to the geometrically non-linear free vibration of fully clamped rectangular plates in order to allow direct and easy calculation of the first, second and higher non-linear fully clamped rectangular plate mode shapes, with their associated non-linear frequencies and non-linear bending stress patterns. Also, numerical results corresponding to the first and second non-linear modes shapes of fully clamped rectangular plates with an aspect ratio α=0·6 are presented. Data concerning the higher non-linear modes, the aspect ratio effect, and the forced vibration case will be presented later.     

Group 4 salalen complexes for the production and degradation of polylactide

In this communication we report the preparation of highly active catalysts for the production of polylactide and the subsequent conversion of polylactide to methyl lactate. The use of these catalysts for potential recycling applications is discussed.     

Salalen aluminium complexes and their exploitation for the ring opening polymerisation of rac-lactide

In this paper we report the first use of Al(III) salalen complexes for the ring opening polymerisation of rac-lactide. Polylactides with narrow polydispersities (PDIs range from 1.04-1.65) and moderate degrees of stereoselectivity were formed. Eight salalen Al(III) complexes have been prepared and fully characterised by solution-state NMR spectroscopy and, where appropriate, single crystal X-ray diffraction. With ligand 3H(2) either a monomeric or dimeric Al(III) species was formed, the dimeric species was favoured at low concentrations. The complexes were tested for the ring opening polymerisation of rac-lactide in toluene at 80 or 100 °C. Interestingly, various tacticities of polymer were formed, which were dependent upon the nature of the group bound to the amine nitrogen centre.     

On the Spectrum of a Class of Strongly Coupled p-Laplacian Systems

Consider the nonlinear coupled elliptic system     

The absorption spectrum of 12C2H2 IV. The regions 7600–9200 cm−1 and 10600–11500 cm−1

The absorption spectrum of ¹²C₂H₂ has been recorded by intracavity laser absorption spectroscopy (ICLAS) in the 10600–11 500 cm^?1 spectral region, where no absorption bands were previously reported. Fifteen bands starting from the vibrational ground state are observed and rotationally analysed. All corresponding excited vibrational levels were assigned using the polyad model, the so-called cluster model (El Idrissi, M.I., Liévin, J., Campargue, A., and Herman, M., 1999, J. chem. Phys., 110, 2074) which allows vibrational energies, rotational B_v constants and, to some respect, relative band intensities to be predicted. Additional data and constants are also provided in the range 7600–9200cm^?1, whenever improving the literature results, from spectra recorded previously at ULB using Fourier transform spectroscopy. The assignment procedure in the range recorded by ICLAS is detailed, leading to a deeper understanding of vibration-rotation and intensity features of the absorption bands within the frame of the cluster model.