Chimeras in random non-complete networks of phase oscillators

We consider the simplest network of coupled non-identical phase oscillators capable of displaying a "chimera" state (namely, two subnetworks with strong coupling within the subnetworks and weaker coupling between them) and systematically investigate the effects of gradually removing connections within the network, in a random but systematically specified way. We average over ensembles of networks with the same random connectivity but different intrinsic oscillator frequencies and derive ordinary differential equations (ODEs), whose fixed points describe a typical chimera state in a representative network of phase oscillators. Following these fixed points as parameters are varied we find that chimera states are quite sensitive to such random removals of connections, and that oscillations of chimera states can be either created or suppressed in apparent bifurcation points, depending on exactly how the connections are gradually removed.     

Structural assignment of monothiocarbonohydrazones by 1H NMR spectroscopy

Analysis of the ¹H NMR spectra of several monothiocarbonohydrazones, some of them synthesized for the first time, shows that they exist as two structural isomers. Whereas, in general, the derivatives of aromatic aldehydes conform to a linear structure, the aliphatic carbonyl derivatives conform to heterocyclic or linear structures, depending on the size of the substituent groups. This dual behaviour is explained in terms of extended conjugation and steric hindrance.     

Electrochemical oxidation of cinnamic acid using stainless steel electrodes

The electro-organic technique is observed to be the modern tool in achieving the oxidation of organic acids to some other useful organic molecules. In the present study, the favourable experimental conditions for carrying out the electrochemical oxidation of cinnamic acid, the experimental set up required and probe for the various products formed have been tried. The anodic process has been carried out at low cost and readily available stainless steel electrode undar aqueous conditions. On identification of the products using chromatographic and spectroscopic techniques, the most probable mechanism has been proposed. To confirm the positive occurrence of the oxidative process under electrolytic conditions, the current — potential study was carried out. The product was analysed by TLC technique, UV and IR spectral studies and identified as 1,4-diphenylbut — 1,3-diene. This work paves a humble way of opening up a new area wherein other electro analytical parameters like polarography, cyclic voltammetry, electrode variation, temperature variation, solvent effects etc. can be studied, along with innumerable substituent effect studies. Paper presented at the 2nd international Conference on Ionic Devices, Anna University, Chennai, India, Nov. 28–30, 2003.     

Recent results from the D? detector

The D? Experiment started taking data in August 1992. We present preliminary results on inclusive jet production, direct photon production, W/Z production and decays, b Physics and first searches fort t production and new particles beyond the Standard Model.     

Two-Stage Flowshop Scheduling Problem with Bicriteria

The two-stage flowshop scheduling problem with the objective of minimizing total flowtime subject to obtaining the optimal makespan is discussed. A branch-and-bound algorithm and two heuristic algorithms have been developed. The results of the experimental investigation of the effectiveness of the algorithms are also presented.     

A new synthesis of atanine,khaplofoline and their analogues

A facile synthesis of Atanine, Khaplofoline and their analogues is described. The method involves condensation of an appropriately substituted 2-quinolone-3-acetic acid with isobutryaldehyde, as the starting point.     

Enantioseparation of 1-phenyl-1-propanol by supercritical fluid-simulated moving bed chromatography

The enantioseparation of 1-phenyl-1-propanol through the supercritical fluid-simulated moving bed (SF-SMB) process is studied. Non-linear isotherms were measured on an analytical column, and used together with the triangle theory for SMB design to select operating conditions for the SF-SMB. Experiments were carried out on a pilot-scale SF-SMB plant at conditions that corresponded to the non-linear range of the isotherm. Under conditions of low feed concentration, complete separation (extract purity = 99.5%; raffinate purity = 98.4%) was achieved. Under conditions of larger feed concentration, the best separation corresponded to an extract purity of 98.0% and a raffinate purity of 94.0%, and yielded a productivity of 110 g of racemate per kg stationary phase per day.     

Enantioseparation of 1-phenyl-1-propanol on Chiralcel OD by supercritical fluid chromatography. I. Linear isotherm

The supercritical fluid chromatography (SFC) separation of the enantiomers of 1-phenyl-1-propanol on the chiral stationary phase Chiralcel OD under linear conditions is studied. Supercritical CO2 modified with methanol is used as a mobile phase. The effect of modifier concentration, pressure and temperature is studied. An empirical isotherm to account for the effect of density of the mobile phase and modifier concentration has been used to model the experimental results. It was observed that the selectivity and resolution were higher at 30 degrees C as compared to those at 40 degrees C.     

Luminescence enhancement induced by aggregation of alkoxy-bridged rhenium(I) molecular rectangles

Self-assembly of rhenium(I)-based molecular rectangles containing long alkyl chains has been achieved in one-pot synthesis by solvothermal methods. An enormous enhancement in the emission intensity, quantum yield, and lifetime of the rectangles has been observed when the solvent medium is changed from organic to aqueous. Addition of water favors the aggregation of Re(I) molecular rectangle resulting in the luminescence enhancement, and this phenomenon has been traced out using light scattering techniques.     

Studies on cellulose acetate and sulfonated poly(ether ether ketone) blend ultrafiltration membranes

New ultrafiltration membranes based on chemically and thermally stable arylene main-chain polymers have been prepared by blending the sulfonated poly(ether ether ketone) with cellulose acetate in various compositions in N,N^′-dimethylformamide as solvent by phase inversion technique. Prepared membranes have been subjected to ultrafiltration characterizations such as compaction, pure water flux, water content, and membrane hydraulic resistance. The pore statistics and molecular weight cut-off (MWCO) of the membranes have been estimated using proteins such as trypsin, pepsin, egg albumin and bovine serum albumin. The pore size increased with increasing concentrations of sulfonated poly(ether ether ketone) in the casting solution. Similarly, the MWCOs of the membranes ranged from 20 to 69 kDa, depending on the various polymer compositions. Surface and cross-sectional morphologies of membranes were analyzed using scanning electron microscopy. The effects of polymer compositions on the above parameters were analyzed and the results are compared and discussed with those of pure cellulose acetate membranes.