Phenoxy herbicidal ammonium ionic liquids

Ammonium ionic liquids with the 4-chloro-2-methylphenoxyacetate anion were synthesized and characterized. Physicochemical properties, such as thermal stability, phase transition temperatures, viscosity, density, refractive index, as well as surface activity and herbicidal activity were determined. Improved physicochemical properties suggest a reduced environmental impact of newly formed group of herbicidal ionic liquids (HILs). HILs with a longer substituent can be characterized with better herbicidal activity in comparison with commercial products.     

Correlation between apparent activation energy and selectivity in the oxidation of benzene over vanadia-molybdena catalysts

The existence of a linear correlation between the apparent activation energy of catalytic benzene oxidation and selectivity with respect to maleic anhydride was found in a series of unsupported vanadia-molybdena catalysts. A plausible explanation for such a correlation is given.

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Optimality and duality for nonsmooth multiobjective programming problems with V-r-invexity

In the paper, we consider a class of nonsmooth multiobjective programming problems in which involved functions are locally Lipschitz. A new concept of invexity for locally Lipschitz vector-valued functions is introduced, called V-r-invexity. The generalized Karush–Kuhn–Tuker necessary and sufficient optimality conditions are established and duality theorems are derived for nonsmooth multiobjective programming problems involving V-r-invex functions (with respect to the same function η).     

Detection of changes in cracked aluminium plate determinism by recurrence analysis

The paper investigates changes in determinism of undamaged and cracked aluminium plates with respect to excitation frequencies. Harmonic excitation of frequencies corresponding to structural resonances has been used to vibrate the plates. Vibration responses have been analysed using recurrence plots and recurrence quantification analysis. The smallest sufficient embedding dimension has been estimated using the false nearest neighbour??s algorithm. Mutual information analysis has been applied to determine the relevant time delays. The results demonstrate that performed analysis indicates changes in dynamic behaviour of the plates with respect to various excitation frequencies and crack modes.     

Identification of volatile lung cancer markers by gas chromatography–mass spectrometry: comparison with discrimination by canines

In this work, a chromatographic method for identification of volatile organic compounds was compared with canine recognition. Gas chromatography and mass spectrometry (GC-TOF MS) were used for determination of concentrations of trace gases present in human breath. The technique enables rapid determination of compounds in human breath, at the parts per billion level. Linear correlations were from 0.83-234.05 ppb, the limit of detection was the range 0.31-0.75 ppb, and precision, expressed as relative standard deviation (RSD), was less than 10.00 %. Moreover, trained dogs are able to discriminate breath samples of patients with diagnosed cancer. We found a positive correlation between dog indications and the ethyl acetate and 2-pentanone content of breath (r = 0.85 and r = 0.97, respectively). The methods presented for detection of lung cancer markers in exhaled air could be used as a potential non-invasive tool for screening. In addition, the canine method is relatively simple and inexpensive in comparison with chromatography.     

Liebig–Denigès Method of Cyanide Determination: A Comparative Study of Two Approaches

The paper compares two approaches to the simulated argentometric titration of cyanide with the use of the modified Liebig?CDenigès (L-D) method, carried out according to GATES and applied with (1) classical and (2) pH-static titrations. Both approaches are discussed thoroughly and the results obtained from calculations are presented graphically. The calculations are performed with the use of an iterative computer program, based on charge and concentration balances and expressions for equilibrium constants, providing all physicochemical knowledge of the dynamic system in question. This way, physicochemical knowledge on complex electrolytic systems can be gained during the analytical procedure, i.e., the physicochemical and analytical knowledge are interrelated. The simulations follow the analytical procedures applied in experimental titrations and so provide an example of searching for the best a priori conditions for the quantitative analysis of cyanide. The computer program for pH-static titrations (described in this paper) enables one to carry out the simulation procedures with different preliminary data (concentrations, volumes).     

Conciliating the nonadditive entropy approach and the fractional model formulation when describing subdiffusion

We consider here two different models describing subdiffusion. One of them is derived from Continuous Time Random Walk formalism and utilizes a subdiffusion equation with a fractional time derivative. The second model is based on Sharma-Mittal nonadditive entropy formalism where the subdiffusive process is described by a nonlinear equation with ordinary derivatives. Using these two models we describe the process of a substance released from a thick membrane and we find functions which determine the time evolution of the amount of substance remaining inside this membrane. We then find ‘the agreement conditions’ under which these two models provide the same relation defining subdiffusion and give the same function characterizing the process of the released substance. These agreement conditions enable us to determine the relation between the parameters occuring in both models.     

A wavelet basis within Bethe ansatz

We describe here an example of a dynamical system which preserves the distance between constituent particles. Namely, we consider the one-dimensional finite magnetic Heisenberg ring of an even numberN of nodes with the spin 1/2, solved exactly by the well-known Bethe ansatz (XXX model). It is described in terms of a number of spin deviations from the ferromagnetic saturation state (a system of Bethe pseudoparticles) which undergo processes of mutual solitonic scattering when moving on the ring. We point out that, when restricting to (i) the subspace of quantum states with two spin deviations and (ii) to the boundary of the Brillouin zone, Bethe pseudoparticles perfectly avoid any mutual scattering. Therefore, each state with a fixed distance between pseudoparticles (the so called basis of wavelets) is already an eigenstate of the initial Heisenberg Hamiltonian. Presented by T. Lulek at the DI-CRM Workshop held in Prague, 18–21 June 2000. The authors are very much indebted to Professors J. Patera and J. Tolar for their invitation to DI-CRM Workshop on Mathematical Physics, and for their kind hospitality during the Workshop.     

The weak lower semicontinuity of the Kobayashi distance and its applications

In this paper we prove the lower semicontinuity with respect to the weak topology of the Kobayashi distance in a bounded, convex and open subset of a reflexive Banach space. We apply this result to the Denjoy-Wolff theorem for condensing mappings in the unit open ball in a strictly convex reflexive Banach space with the Kadec-Klee property. Received June 30, 1998 / in final form December 20, 1999 / Published online July 20, 2000