Analysis of MDOF nonlinear systems using associated linear equations

Until now, the recently developed associated linear equations (ALEs) have been used for the analysis, identification and control of only single-degree-of-freedom (SDOF) systems. This form of the theory has proved adequate for the analysis of certain cases of interest in actuator/sensor technology; however, it is more common to find the multi-degree-of-freedom (MDOF) case in structural dynamics and this paper extends the theory of ALEs to this latter case.     

Competitive transfer of H+ and Al(III) ions facilitated by a Prometrine herbicide through a liquid/liquid interface

The transfer of aluminium(III) across the water/1,2-dichloroethane interface facilitated by the herbicide Prometrine (PROM) was investigated using cyclic voltammetry. In the presence of PROM in the organic phase, the transfer of Al(III) and H⁺ from the aqueous to the organic phase was observed and the competition between these two cations for the herbicide was analyzed at different pH values. At pH 4.50, it was possible to determine the formation of an Al(III):PROM complex in the organic phase, with a stoichiometry of 1:3 and a charge of 2⁺, indicating that the species in the complex with PROM is Al(OH)²⁺.     

Osmotic dehydration kinetics of banana slices considering variable diffusivities and shrinkage

This article studied the use of diffusion models to describe variation of water quantity and sucrose quantity during osmotic dehydration of bananas cut into cylindrical slices. Bananas with radius of 1.7 cm and 18 °Brix (on average) were cut into 1.0 cm of thickness. A solution was proposed for the diffusion equation in cylindrical coordinates using the finite volume method, with fully implicit formulation. The diffusion equation was discretized assuming diffusivities and dimensions with variable values for the banana slices. Boundary conditions of the third kind have also been considered. The osmotic dehydration experiments were conducted in binary solutions (water and sucrose) under conditions of 40 and 60 °Brix and temperatures of 40 and 70°C. Mathematical modeling was proposed to describe the processes presented good results for water quantity and sucrose quantity, with good statistical indicators for all fits.     

Evaluation of tropical grasses for milk production by dual-purpose cows in tropical Mexico.

Two experiments using the Cornell Net Carbohydrate and Protein System were conducted to characterize the carbohydrate and protein fractions and corresponding rates of digestion of 15 tropical pasture grasses and to evaluate their ability to support milk production by dual-purpose cows. In the first experiment, ranges in carbohydrate and protein fractions of 15 grasses at 35 to 42 d of regrowth were: neutral detergent fiber (NDF) 63.5 to 74.9% of DM; permanganate lignin 4.7 to 7.8% of NDF; CP 5.5 to 11.9% of DM; and soluble protein 15.1 to 44.1% of crude protein (CP). The ranges of rates of digestion expressed as percent per hour were neutral detergent solubles (7.5 to 27.4); NDF (3.8 to 8.4); and neutral detergent insoluble protein (2.9 to 9.5). Predictions of the amount of milk that could be produced based on the amount of metabolizable energy supplied by the diet decreased 35% when NDF increased from 60 to 80%, and increased 88% when the rate of digestion of NDF increased from 3 to 6%/h. The milk production that could be sustained based on metabolizable protein in the diet doubled as CP increased from 4 to 12%. In the second experiment, nitrogen fertilization reduced NDF 7.3% and increased CP 84% without changing protein solubility, resulting in increased rumen nitrogen and metabolizable protein balances. With all forages, the Cornell Net Carbohydrate and Protein System predicted that availability of metabolizable protein would limit milk production. Predicted microbial growth was limited by ruminally available protein rather than by available carbohydrate.     

Aggregation profile characterisation in dielectrophoretic structures using bacteria and submicron latex particles

A novel quantitative characterisation method for the measurement of anomalous low frequency aggregation processes on dielectrophoresis electrodes has been developed. Experimental evidence is provided for the relationship between the aggregation effect and AC electro-osmotical fluid motion theory. The aggregation profile dependence for E.coli bacteria, as a function of frequency and applied field, has been quantitatively examined. Additional experimental observations of the aggregation profiles of latex particles with dimensions of hundreds of nanometres, also confirm the relationship between this aggregation effect and the mentioned fluid motion theory.