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Jiří Blahovec

Abstract

The paper is based on data about local cereal prices in Bohemia recorded in the course of 46 years (1770-1816) by F.J. Vavák, Czech farmer living close to Prague. This information appeared in a series of his memoirs published within 1907-1938 and in 2009. The data analysis shows that annual means of prices of wheat, rye, and barley are relatively well correlated and can be used for illustration of the state monetary situation. A higher variation of the annual mean values was observed only in times of crop failure and was also related to the new harvest. The data obtained for pea differ from the data mentioned above. It was shown that the market prices were influenced mainly by crop failures caused by weather and climate and by the state monetary policies. The money purchasing power was influenced either by objective causes, like crop failures of reversible character, or by subjective changes caused mainly by inflationary monetary policies which in the case of Austria had conduced to a state bankruptcy.

Open access

Jiri Blahovec and Magdalena Lahodová

Abstract

The seeds of barley, oat, rye, and two varieties of wheat were studied during wetting thereof with special respect to changes in their mass and dimensions. Two levels of wetting were used: 6-h wetting close to the end of imbibition, and 24-h wetting close to the start of germination. The results of these experiments show that the measured quantities can be well described by the Gaussian distribution. Gaussian distribution is applied for description of the wetting effects that can be well approximated also by a second-degree polynomial of the initial state. Even though an increase in the mass, length, width, and thickness was the main effect of wetting, opposite trends in some dimensionally dependent cases were also observed. Drying of the wetted specimens led to a state that differed only slightly (less than 1%) from the initial state. Among the dimensional characteristics, the highest changes were observed in the grain length.

Open access

Jiří Blahovec and Pavel Kouřím

Abstract

A combined thermal analysis (including a dynamic mechanical analysis and a dielectric thermal analysis) was applied to the cortex tissues of long-stored potatoes in the temperature range of 30-90°C, with the constant air relative humidity of 90%. Two heating rates, i.e. 1°C min−1 and 0.5°C min−1, were used for temperature scanning. The obtained results were found to differ in the inspected temperature range, indicating either a different mode of drying or differences in the starch gelatinization mechanism, the latter being usually controlled by water availability in contact with starch in both tests. The observed results indicate new possibilities in the cooking strategies that are usually applied to potatoes.

Open access

Jakub Lev and Jiří Blahovec

Abstract

Image analysis is widely used for monitoring seeds during germination, and it is often the final phase of germination that is subjected to the greatest attention. However, the initial phase of germination (the so-called imbibition) also exhibits interesting behaviour. This work shows that image analysis has significant potential in the imbibition. Herein, a total of 120 seeds were analysed during germination tests, and information about seed size and shape was stored and analysed. It was found that the imbibition can be divided into two newly defined parts. The first one (‘abrupt imbibition’) consists mainly of the swelling of the seed embryo part and lasts approximately one hour. The second one, referred to as ‘main imbibition’, consists mainly of spatial expansion caused by imbibition in the other parts of the seed. The results presented are supported by the development of seed cross area and shape parameters, and by direct observation.