The influence of oxidizing agents on water extracts of rye flour

The main constituents of rye flour extracts are proteins and pentosans. After cross-linking under the action of oxidizing agents those components are able to bind much more water than in their native (prior to modifications) state. As a consequence rheological properties of extract are changed.It was observed that kinematic viscosity of water extract of rye flour decreases rapidly with time. The reason for this behavior could be high enzymatic activity of flour extract.It was also found that the addition of hydrogen peroxide in the absence of additional peroxidase (which is naturally present in 1:9 or 1:1 water extracts of flour) causes the greatest increase in viscosity, due to the cross-linking of soluble polymers. Moreover after the addition of H₂O₂ to water extracts strong gels were obtained, which were characterized by tan δ = 0.5 (tan δ < 1). Moreover G′ was independent of frequency, which also suggests cross-linking of the pentosans.The addition of ascorbic acid, which is known to act preferably on gluten proteins, to 1:9 or 1:1 flour extracts had only a little effect on viscosity. In this case the values of tan δ = 0.9 were close to 1, which is typical for a weak gel.The application of inactivated rye flour extract, containing mainly proteins and pentosans, proved stronger effect of H₂O₂ in comparison to ascorbic acid on polymer cross-linking, but only after the addition of peroxidase. The gel obtained with H₂O₂ and peroxidase was also characterized by low tan δ = 0.4.The results indicate, that pentosans are the main subject of cross-linking reactions in rye flour water extracts.     

Spontaneous formation of polylactide stereocomplex microspheres containing metal ions

Linear poly(l ‐lactides) (PLLAs ) and poly(d ‐lactides) (PDLAs ) with M _n in the range 2000 ? 4300 containing a different number and placement of carboxyl groups were obtained via cationic ring‐opening polymerization and post‐polymerization functionalization. PLA stereoisomers (PLLA ‐(COOH )_x and PDLA ‐(COOH )_x , where x = 1 ? 3) were used for the investigation of stereocomplexation in solution performed in the presence of metal cations such as Ca²⁺, Mg²⁺, Zn²⁺, Fe³⁺. Spherical microparticles with a diameter in the range 0.7 ? 3.0 µm were obtained in all cases which was confirmed on the basis of scanning electron microscopy (SEM ) analysis. The microsphere size and homogeneity were analyzed depending on the stereocomplexation conditions and the molecular weight as well as the number of carboxyl end groups in the PLLA and PDLA used for stereocomplexation. The PLA microspheres obtained were analyzed by Fourier transform IR spectroscopy, wide angle X‐ray spectroscopy and energy‐dispersive X‐ray spectroscopy methods which confirmed the presence of metal cations inside. The application of regular microspheres with metal ions as drug delivery systems is considered. © 2016 Society of Chemical Industry     

A numerical approach to nonlinear propagation of light in photorefractive media

The article presents a new approach to the analysis of light propagation in photorefractive materials. The discussed numerical method can be used for an analysis of the dynamics of nonlinear effects taking place in those media in which an analytical approach requires the use of approximations or is impossible. As an example of how the method works, the results of simulation are shown, illustrating the process of spatial solitary wave formation in two materials: a photorefractive semiconductor and a ferroelectric crystal.     

Parameter estimation of the electrothermal model of the ferromagnetic core

The paper presents a new form of the electrothermal model of the ferromagnetic core for SPICE and the way, in which the parameters of the model are determined. The manner of determining magnetic, geometric and thermal parameters of this model is described. The correctness of the proposed model and the manner of determining the values of the parameters are verified by comparing the calculated and measured characteristics of the selected ferromagnetic cores.     

Electron spin resonance of FeVO4

We report on electron spin resonance (ESR) investigations of a FeVO₄ single crystal. Temperature and angular dependences of ESR resonance positions were measured and calculated in temperature range of 35–100 K. The spectra show rich angular dependences of the linewidth, the shape and the resonance field. They consist of a single broad line with asymmetric distortion. Due to the low symmetry of the crystal lattice this distortion can be explained by taking into account the influence of non diagonal dynamic susceptibility.     

A Critical Role for the Presence of Lignocellulosic Material in the Determination of Wood Buffering Capacity

The currently used determinations of wood buffering capacity, which are based on pH-metric titrations of aqueous wood extracts, neglect the effect of lignocellulosic material and the role of its insoluble constituents. This study examined the influence of the presence of wood in a system subjected to titration. A comparison of the results obtained from pine chip extracts and chip suspensions showed that the presence of wood and the wood-to-water ratio were critical factors that affected the measurement of the wood buffering capacity. The evidence showed that the resulting determination may vary by up to six times (0.28–1.99 ml/g), depending upon the conditions of the titration. In addition, it was found that the presence of wood had a neutralizing effect over the course of prolonged pH observations.     

ANN–supported control strategy for a solid oxide fuel cell working on demand for a public utility building

The idea of control strategy of SOFC operating to meet demand of a public utility building was presented. The strategy was formulated with the support of Artificial Neural Network. The network was used to predict the demand for electricity. The calculations were carried out on the example of a building of the Institute of Heat Engineering Warsaw University of Technology. The control strategy is influenced by various factors depending on changes in market conditions and operating characteristics of the cell. We can define different objective functions eg: working for own needs, for maximum profit and maximum service life. The article presents a simulation of SOFC operation for demand profile of the IHE building from the selected time period.     

Improving comparability of hydrogen storage capacities of nanoporous materials

We present results of investigations into improving methods by which gas sorption data are collected and reported. The focus is the accurate comparison of hydrogen storage capacities of different nanoporous materials. The aim is to produce a more rigorous approach to the assessment of the hydrogen storage capacities of different nanoporous materials through formulation of meticulous and systematic data collection routines for production of universally reproducible H₂ isotherms over a wide range of pressure and temperature conditions. Effects of a range of experimental variables are examined and recommendations for the optimisation of data collection routines are given.