Generalized synchronization of chaos in identical systems with hidden degrees of freedom

We demonstrate generalized synchronization of chaos in a two-mode laser system. The total intensity of the laser output (the sum of the individual mode intensities) is used as the drive signal. This lumped variable transmitted to the identical response system does not generate identical synchronization. Generalized synchronization is observed instead of identical synchronization because of the hidden internal degrees of freedom.     

A priori bounds on difference quotients of solutions to some linear uniformly elliptic difference equations

Second order difference quotients of solutions to a class of linear uniformly elliptic difference Dirichlet problems are bounded in terms of quantities which depend on the coefficients of the operator, the inhomogenous term, the boundary values and the domain-which we take to be a rectangle. The results we obtain have theoretical and practical applications.     

The empirical prediction of tractor-implement field performance

The performance of a two-wheel-drive tractor was measured in 14 different fields when ploughing. Gear number and the number of plough bodies were varied to search for the combination which gave optimum work rate. Tractor and plough performance were modelled using empirical relationships, the measured and predicted performance compared and reasonably good correlation found.     

Chromatographic methods for product-profile analysis and isolation of oligosaccharides produced by heparinase-catalyzed depolymerization of heparin.

A two-dimensional chromatography method for monitoring the formation of oligosaccharides produced by heparinase-catalyzed depolymerization of heparin is reported. In the first step of the two-dimensional method, the depolymerized heparin is size-fractionated by high-performance gel permeation chromatography (HPGPC). The size-uniform fractions are then separated on the basis of charge by strong anion-exchange (SAX) HPLC on a high resolution CarboPac PA1 column. To demonstrate application of the two-dimensional product-profile analysis method, data are presented for the heparinase I-catalyzed depolymerization of heparin in the absence and presence of histamine, a ligand that binds site-specifically to heparin. Results from the two-dimensional analysis indicate that histamine alters the extent of depolymerization and the product-profiles for the tetrasaccharide and hexasaccharide fractions. The use of CarboPac PA1 columns for the semi-preparative scale separation of oligosaccharides in size-uniform fractions isolated from depolymerized heparin by low-pressure (gravity flow) GPC is also reported. The semi-preparative scale CarboPac PA1 column gives high resolution and excellent reproducibility after repeated use over an extended period of time, making it possible to reliably combine fractions from multiple separations. The oligosaccharides are eluted from the CarboPac PA1 column with a NaCl gradient at relatively low pH (3 or 7) where they are stable. An efficient two-step procedure is described for desalting oligosaccharides separated     

Comparison of the tractive performance of a tractor driving wheel during its first and second passes in the same track

The tractive performance of a conventional 13.6–38 tractor driving wheel tyre was measured in 19 different fields using the NIAE Single Wheel Tester. In each field the performance was measured on the undisturbed ground and again in the rut formed by a previous run with the same tyre. The second run simulated the operation of the rear wheels on a four-wheel drive tractor.The performance during the second pass was generally better than during the first pass. On average, the coefficient of traction increased by 7%, rolling resistance reduced by 11% and maximum tractive efficiency increased by 5%. The improvement increased as ground conditions deteriorated but was never large enough to fully explain the differences in performance between two and four-wheel drive tractors previously measured. It is suggested, therefore, that these differences may be primarily due to the greater ease with which power, weight, implement size and working speed can be matched with four-wheel drive tractors.