Magyarországi vörösagyagok összehasonlító vizsgálata = Comparative study of red clays in Hungary

A magyarországi vörös talajok csoportosítása humuszminőségi, mikromorfológiai és tápanyag-gazdálkodási vizsgálat alapján történt. A humuszminőséget jellemző görbék és stabilitási koefficiens alapján az alábbi csoportokba rendeztük: - nagy stabilitási koefficiensű humuszminőségű talajok, - közepes stabilitási koefficiensű talajok, - kis stabilitási koefficiensű, gyengébb humusz-minőségű talajok. A fosszilis vörösagyagok humusza viszonylag rosszabb minőségű, hasonlít a trópusi talajokéhoz. A művelt reliktum vörös talajok humusz-minősége kedvezőbb. A hazai vörös talajok harmadkori eredetűek, de tulajdonságaik alakításában a jelenkori talajképző tényezők is részt vettek. Talajtani, ásványtani és mikromorfológiai vizsgálatok, valamint a mállottság foka alapján nyolc csoportba soroltuk a magyarországi vörösagyagokat. Néhány esetben (Gödöllő, Hatvan, Mád, Muzsla, Mátrakeresztes stb.) agyagbevonatok láthatók, melyek a kilúgzódás mikromorfológiai jelei. Az agyagbemosódás legnagyobb mértékű a Hatvan és Kővágószőlős mintákban. A duzzadás-zsugorodás a vázrészek körül foltokban, zónákban az alapanyag orientálódását idézi elő (Gödöllő, Gyöngyöstarján, Hatvan, Jósvafő, Kakasd, Kővágószőlős, Mád stb.). A gyöngyöstarjáni, ostorosi és csopaki talaj és szőlőminták vizsgálata alapján a szőlő tápanyag felvétele a vörösagyagokon zavartalan. | Hungarian relic and fossil red-clays are classified into 8 groups based on pedological, mineralogical and micromorphological analysis. Results of humus quality groups formed by stability coefficients and humus quality curves are the follows: - humus materials with high stability, - mean humus quality materials, - soils with low humus quality The fossil red-clays have worse humus quality, similar with the tropical red-soils. Cultivated relict red-soils have improved humus quality. Hungarian red-clays are derived from the Tertiary Period under tropical or subtropical climate, but theirs features were formed ecological conditions of present epoch too. In micromorphological analysis occurences of clay coating interpreted features of illuviation and weathered extent. The speckled and granostratied b-fabric of the groundmass whose occurence is mainly due to the swelling and shrinking, were observed in samples from Gödöllő, Gyöngyöstarján, Hatvan, Jósvafő, Kakasd, Kővágószőlős, Mád. Occurences of clay coating in samples of sites in Gödöllő, Hatvan, Mád, Muzsla, Mátrakeresztes were interpreted as a micromorphological features of illuviation. The most illuviation coatings and infillings were observed in samples from Hatvan and Kővágószőlős. According to analysis of soil and vine samples from Gyöngyöstarján, Ostoros and Csopak, it is declarable that nutrient absorption is undisturbed

Improvement of the Microbiological Safety of Two Chilled Semi-Prepared Meals by Gamma Irradiation

Experimental batches of a stuffed pasta product, tortellini, and slightly pre-fried breaded reconstituted turkey steaks with cheese and ham filling, Cordon Bleu, were prepared according to commercial recipes, then inoculated with 104 CFU/g of Staphylococcus aureus (in case of tortellini) and with 106 CFU/g of Listeria monocytogenes (in case of Cordon Bleu) prior to packing in plastic bags under a gas atmosphere of 20 % CO2 and 80 % N2. The inoculated packages were irradiated at 3 kGy (tortellini) and 2 kGy (Cordon Bleu) with a 60Co radiation source. The applied radiation doses were sensorially acceptable for these products. The experimental batches of tortellini were stored at 15 °C, while the Cordon Bleu samples were stored at 5 and 9 °C. Unirradiated samples were kept together with the respective irradiated ones. Storage was continued for 4 weeks and microbiological tests were performed before and after the irradiation, and subsequently after every seven days. Besides selective estimation of the counts of the test organisms, total aerobic counts were evaluated in all samples and in case of Cordon Bleu, colony counts of lactic acid bacteria, Enterobacteriaceae, sulphite reducing clostridia, yeasts and moulds were also selectively estimated. The 3-kGy dose reduced the S. aureus count in tortellini below the detection limit (logCFU=0.26), and it remained undetectably low in the irradiated samples during all 28 days of storage, while the S. aureus count in the unirradiated samples increased up to 108 CFU/g during 8 days. The Listeria count in Cordon Bleu was reduced by irradiation from the initial count of 6.1 to 3.5 logCFU/g. At 5 °C storage, this residual count remained stagnant up to 3–4 weeks, but started to increase at 9 °C after one week of storage. In the unirradiated samples, the Listeria count increased hundred-fold during 4 weeks at 5 °C, and during 2 weeks at 9 °C. Sulphite reducing clostridia were, and remained, undetectable (<0.48 logCFU/g) in all samples even at 9 °C. The limiting factor of the shelf-life of the unirradiated poultry products was the growth of lactic acid bacteria at 9 °C, whereas enhanced lipid oxidation was an unwanted side-effect of radiation treatment. From these studies it can be concluded that the potential risk posed by the investigated non-sporeforming pathogenic bacteria could be considerably reduced by gamma irradiation, however, storage temperature remains a crucial factor of safety and methods should be developed to counteract the lipid-oxidative effect of the radiation processing

Rheological Behaviour of Pigment Filled Polymer Dispersions: The influence of electric field

Rheological properties of materials are related to their response to applied stress. The field induced chain formation of a large number of organic and inorganic substances such as starch, aluminium oxide, ferric oxide, carbon black, ion-exchange resins, and polymer powders have been studied mainly in insulating oils. Much less is studied and understood the electrorheological effect of pigments in polymer dispersions. Titanium dioxide is one of the most frequently used surface coatings due to its high-quality and ecologically acceptable properties. In the present paper the authors first review the basic principle of electrorheology, then it is followed by experimental studies on structuring and rheological properties