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  • Author or Editor: P. Sipos x
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The clay mineral composition of four brown forest soil profiles (Luvisols) developed on different parent rocks was studied in detail to determine the major clay mineral alteration processes. In the studied profiles a siltstone bedrock weathered to chlorite/vermiculite and vermiculite in a less developed, shallow soil profile, while the major product of soil formation in a clayey, well-developed deep soil is a typical soil montmorillonite with heterogeneous charge distribution. The most possible pathway of clay alteration is illite smectitization via charge reduction, and considerable degradation of smectite in the soil formed on limestone. On the contrary, weathering of andesite parent rock involves the formation of low charged smectite altering to high charged vermiculite during pedogenesis.

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Representative straw samples from various cereals were analysed to determine their chemical composition and calorific value. It was found that the chemical composition data given in previous feeding tables can be applied to characterise modern varieties, as only the crude fat contents of oats and winter wheat were significantly higher than the available reference data, while the ash contents were lower. The calorific value of cereal straw was equal to or in some cases greater than that of energy grass, so cereal straw could be competitive with energy grass, due to its large cultivation area and the properties and value of its by-products.

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Investigations on the baking quality of winter wheat, which is the most important bread cereal in Hungary, have been in the focus of attention for a long time. it is useful to study the theoretical and practical aspects of European quality testing systems, because different European methods are generally mutually accepted in the EU. Many recognised testing methods have been developed in Hungary over the last hundred years. In the present experiments studies were made on the effect of the year, variety and mineral fertilization and their interactions on alveographic parameters. in the years examined, the main factor which determined the alveographic values was found to be the variety. fertilization had a significant effect on the examined parameters, but in most cases no regular trends were observed. The year only modified wheat quality in interactions.

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Changes in the chemical contents of the kernels of maize hybrids were analysed in three consecutive years (one dry, one arid and one wet) in samples originating from irrigation and fertilisation experiments. The results indicated that while irrigation and wet years had a protein-decreasing effect, the water supply did not influence the starch and oil contents. Under the influence of fertilization, the calcium and zinc contents of maize kernels decreased to varying degrees depending on the hybrid, while the sulphur contents changed parallel to the protein contents. Based on these data and on the use of more modern measuring equipment, tables giving recommendations for chemical contents should be revised.

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This paper proposes a non-linear mathematical model that makes it possible to simulate the batch alcoholic fermentation of white wine. The model was developed in stages, considering the yeast cells’ physiological states. The parameters of an equation that describe the latent period were calculated considering temperature influence. The biomass equation was established starting from the Monod model and validated with experimental data. For substrate consumption and product, the Bovée and Strehaiano model has been used. The mathematical system was completed with heat transfer equations in bioreactor and jacket. The model was implemented as a Matlab S-function and results were compared with the experimental data.

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Based on a nonlinear model, this article realizes an investigation of dynamic behaviour of a batch fermentation process using direct sensitivity analysis (DSA). The used nonlinear mathematical model has a good qualitative and quantitative description of the alcoholic fermentation process. This model has been discussed and validated by authors in other studies. The DSA of dynamic model was used to calculate the matrix of the sensitivity functions in order to determine the influence of the small deviations of initial state, control inputs, and parameters from the ideal nominal values on the state trajectory and system output in time. Process optimization and advanced control strategies can be developed based on this work.

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Abstract  

A study was made of the possibilities of gradually decreasing the concentration of the toxic organic solvent in the process of microsphere preparation. Ammonio methacrylate copolymer-based microspheres were prepared by spray drying or conventional solvent evaporation techniques, and compared. The formulations were designed by varying the preparation methods and the concentrations of four polar cosolvents as independent variables. DSC was used to study the relationship between the changes in the independent variables and three of the main thermal events of the microspheres. Raman spectroscopy was used to investigate and confirm the possible interactions between drug and copolymer. Appropriate choice of the independent variables led to the molecularly dispersed drug in the polymer matrix. It was demonstrated that only the nature of the preparation method caused significant variations in the structure and thermal behaviour of the microspheres.

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Abstract  

The main purpose of our study was to produce microspheres containing diltiazem hydrochloride and to perform the thermoanalytical examination of the components and microspheres. Thermal analysis is a very frequently used method in the preformulation tests of solid dosage forms. Diltiazem hydrochloride is a calcium-channel blocker with short biological half life, so it is a potential candidate for sustained or controlled release dosage forms. Various techniques are available for the microencapsulation of drugs. The technique of spray-drying was used during our investigations. It was found that the crystalline form of the active agents could not be observed in the drug-loaded chitosan microspheres, which indicates the molecular dispersion of the drug in the matrix. It was established that the preparation conditions influenced the morphology and size of the particles. Moreover, the sphericity of the microspheres was good. On the basis of our investigations, the 1:1 diltiazem hydrochloride–chitosan ratio is suggested as the best ratio.

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In the field of product development and quality assurance flavour lexicons are widely used. These systems include the definition of all attributes and the relevant reference materials or reference samples. With the application of these lexicons more reliable results can be acquired and it can be very helpful to the assessors in sensory analysis. The main purpose of our further research was to establish a flavour language for table margarines. A well-trained margarine expert panel was already established and also an appropriate sensory method (QDA) was chosen. However, the applied sample presentation design also has a strong influence on the results. In this study the effect of two types of test protocols were compared on the performance of the expert panel. The results of the sensory panel were monitored using univariate (F-plot, MSE-plot, p*MSE-plot) and multivariate statistical methods (Tucker-1 correlation loading plot) by PanelCheck. With application of the side-by-side protocol (SBS) the panel agreement and the ability to discriminate the samples and the repeatability of the panel were considerably improved against using the sequential monadic presentation protocol (SM). The explained variance of the first occasion was 74.8% and in case of the application of SM was 55% for PC1.

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In January and March 2000 two tailings dam failures occurred in the upper Tisza catchment area near Baia Mare and Baia Borsa (Romania). These resulted metal pollution of the Lápos-Szamos-Tisza and Visó-Tisza river systems. The mining accidents were followed by a flood event. Many studies reported that elevated Cu, Zn, Pb and Cd concentrations were observable in water, sediment and in soils of flooded areas as well. Mine wastewater contained large amounts of suspended solids with high metal concentrations. The aims of this study were the determination of Lakanen-Erviö extractable, easily available metal contents of the soil samples collected in 2011 from Tivadar floodplain, a pasture near Vásárosnamény, a pasture near Rakamaz and Tiszacsege floodplain along the Tisza, and the comparison of these data and the results of an earlier study in 2000.According to our results the soil profiles of Vásárosnamény, Rakamaz and Tiszacsege is considered to be polluted by Zn, Pb and Cd. Low metal concentrations were found in the soil samples originated from Tivadar floodplain that was not affected by the first tailings pond failure. According to the statistical analyses of these data it can be established that during the 11-year period the easily available Cd, Cu, Zn and Pb contents of the pasture near Vásárosnamény increased significantly. This may caused by the periodical flood events or the mobilization of the pollutants. Further investigations (solid state partitioning of metals by sequential extraction) are required to find an explanation of this increase.

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