The follow up research into the IHDS process was carried out with a Couette device. The outcome of this study provides a comprehensive understanding of the effect that both the agitation intensity and the agitation time have on the kinetics and the mechanism of the aggregation process. The results obtained confirm the very favourable influence of high agitation intensity for the formation of more compact and dense aggregates than those formed by the accustomed flocculation conditions with low agitation intensity. This research also proved that the agitation intensity and time are the inherent means profoundly influencing the properties of the resultant aggregates such as their size, shape, density and homogeneity. Further, it was confirmed that the aggregation process passes through a minimum. Furthermore, it was verified that the aggregation process takes place in four consecutive phases, namely a) the phase of formation, b) the phase of compaction, c) the phase of a steady (equilibrium) state and d) most probably the phase of inner restructuring. The pattern of the aggregates development in these phases remains the same irrespective of the magnitude of the velocity gradient applied but the time at which these phases are completed is velocity gradient dependent. Last but not least this study proved that the dimensionless product Ca = G T = const. has no general validity. and Výzkum tvorby agregátů metodou IHDS pokračoval s Couettovým typem flokulačního zařízení. Výsledek této studie umožňuje porozumět vlivu intenzity a času míchání na kinetiku a mechanismus agregačního procesu. Získané výsledky potvrzují velmi příznivý vliv vysoké intenzity míchání na tvorbu kompaktnějších a hustších agregátů než jsou ty vytvořené běžnými flokulačními podmínkami s nízkou intenzitou míchaní. Tento výzkum také potvrdil, že intenzita míchání ve spojení s časem je přirozeným prostředkem výrazně ovlivňujícím vlastnosti výsledných agregátu jako je jejich rozměr, tvar, hustota a homogennost. Dále bylo potvrzeno, že agregační proces probíhá ve čtyřech následných fázích. Jedná se o: a) fázi tvorby, b) fázi zhutňování, c) fázi rovnovážného stavu a d) s největší pravděpodobností fázi vnitřní restrukturalizace. Struktura agregátů vytvořených v jednotlivých fázích je obdobná bez ohledu na velikost použitého rychlostního gradientu, ale čas potřebný k ukončení těchto fází je závislý na velikosti použitého rychlostního gradientu. V neposlední řadě tato studie potvrdila, že bezrozměrné kritérium Ca = G T = = konst. nemá všeobecnou platnost.
On the basis of the results of calibration of current meters at water of varying temperatures, a hypothesis that water temperature influences measured water velocities was formulated. The analysis of our long-term data showed that the water temperature does have an influence on measured water velocity. This influence can be taken into account for practical purposes as a contribution to the uncertainty of measurements. The influence depends on the type of current meter propeller. This paper presents results obtained for the Ott C-2 current meter with propellers of the types 1, 2, 3, 5 and 6. Our analysis showed that the uncertainty is equal or less than 5% for measurements carried out in water with temperatures above 8°C. The differences between measured water velocities for water temperatures 5°C and 20°C reached maximum 6% (depending on the propeller) in a slowly flowing water (rotational frequency n = 1 s-1 ). For rotational velocity n ≥ 2 s-1 the differences between velocities measured at water temperatures 5 and 20°C were mostly under 3%. The less influenced propeller is of type 3 for which the uncertainty of measurement does not reach 5% even for water temperature 1ºC if the rotational frequency is bigger than 0.7 s-1 .
Hormonálna antikoncepcia je dnes ponúkaná ako niečo prospešné pre zdravie ženy, avšak nové vedecké poznatky poukazujú aj na výskyt jej nežiaducich účinkov a rizík. Cieľom štúdie bolo zistiť úroveň informovanosti žien o nežiaducich účinkoch a rizikách antikoncepcie zo strany lekárov/ pôrodných asistentiek. Ako výskumný nástroj bol vytvorený neštandardizovaný dotazník. Celkovo bolo v gynekologických ambulanciách distribuovaných 130 dotazníkov, vrátilo sa 108 (responzibilita: 83,07 %), pričom 8 dotazníkov bolo vyradených pre nesplnenie kritérií. Výskumu sa zúčastnilo 100 respondentiek s vekovým priemerom 28,7 (±5,28) rokov, ktoré užívali hormonálnu antikoncepciu, a podpísali informovaný súhlas so zapojením do výskumnej štúdie. Najčastejšími dôvodmi užívania hormonálnej antikoncepcie u respondentiek nášho súboru boli: zamedzenie plodnosti (66%) a zdravotné dôvody (34%). Zistili sme, že 54 % respondentiek bolo informovaných zo strany lekárov/ pôrodných asistentiek o nežiaducich účinkoch hormonálnej antikoncepcie avšak 51,85 % z nich bolo informovaných nedostatočne. O rizikách zvyšujúcich nežiaduce účinky HAK bolo informovaných 64 % respondentiek. Najčastejšie nežiaduce účinky HAK u respondentiek sa zaznamenali bolesť hlavy, emočná labilita, zníženie libida. Úroveň informovanosti žien o nežiaducich účinkoch antikoncepcie zo strany lekárov/ pôrodných asistentiek môžeme hodnotiť ako neuspokojivú, preto by bolo potrebné zlepšiť a skvalitniť edukáciu žien o hormonálnej antikoncepcii ., Hormonal contraception is nowadays offered as something beneficial for the woman´s health, but the new scientific knowledge is showing us its undesirable effects as well. The objective of the study was to find out the awareness level of women about the undesirable effects and risks of hormonal contraception from the side of doctors/ midwives. As a research tool, we have created a non- standardized questionnaire. Overall we have distributed 130 questionnaires in the gynaecological centres, 108 questionnaires have been returned (recoverability: 83.07 %). 8 questionnaires have been excluded from the research due to the incomplete information. 100 respondents, with the average age of 28.7 (±5.28) years, that have used hormonal contraception have participated in this research and signed the written agreement about their participation in this research study. The most frequent reasons for using the hormonal contraception by our respondents were the following ones: fertility prevention (66 %) and healthy reasons (34 %). We have found out that 54 % of respondents were informed from the side of doctors/midwives about the undesirable effect of hormonal contraception, however 51.85 % from them have been informed insufficiently. 64 % of respondents have been informed about the risks of increased effects of hormonal contraception. The most frequent effects of hormonal contraception by our respondents were headache, emotional instability, and decrease of libido. The awareness level of women about the undesirable effects of hormonal contraception from the side of doctors/midwives has been evaluated as unsatisfactory. So it would be necessary to improve the education of women in the area of hormonal contraception., Mazúchová L., Kelčíková S., Markusová K., and Literatura
The wetting rate of soil is a measure of water repellency, which is a property of soils that prevents water from wetting or penetrating into dry soil. The objective of the present research was to examine the initial water repellency of organic manure amended soil, and its relation to the soil organic matter (SOM) depletion rates in the laboratory. Soil collected from the Wilpita natural forest, Sri Lanka, was mixed with organic manure to prepare soil samples with 0, 5, 10, 25, and 50% organic manure contents. Locally available cattle manure (CM), goat manure (GM), and Casuarina equisetifolia leaves (CE) were used as the organic manure amendments. Organic matter content of soils was measured in 1, 3, 7, 14, and 30 days intervals under the laboratory conditions with 74±5% relative humidity at 28±1°C. Initial water repellency of soil samples was measured as the wetting rates using the water drop penetration time (WDPT) test. Initial water repellency increased with increasing SOM content showing higher increasing rate for hydrophobic CE amended samples compared with those amended with CM and GM. The relation between water repellency and SOM content was considered to be governed by the original hydrophobicities of added manures. The SOM contents of all the soil samples decreased with the time to reach almost steady level at about 30 d. The initial SOM depletion rates were negatively related with the initial water repellency. However, all the CE amended samples initially showed prominent low SOM depletion rates, which were not significantly differed with the amended manure content or the difference in initial water repellency. It is explicable that the original hydrophobicity of the manure as well has a potentially important effect on initiation of SOM decomposition. In contrast, the overall SOM depletion rate can be attributed to the initial water repellency of the manure amended sample, however, not to the original hydrophobicity of the amended manure. Hydrophobic protection may prevent rapid microbial decomposition of SOM and it is conceivable that hydrophobic substances in appropriate composition may reduce organic matter mineralization in soil. These results suggest the contribution of hydrophobic organic substances in bioresistance of SOM and their long-term accumulation in soils.
The present work investigates the effect of the flow profile induced by an inlet condition on the roll-wave evolution in turbulent clear-water flows. The study employs theoretical and numerical analyses. Firstly, the influence of the inlet condition on the spatial evolution of a single perturbation in a hypercritical flow is examined through the expansion near a wavefront analysis. The results show that an accelerated unperturbed profile reduces the disturbance spatial growth. A decelerated profile causes an increase. The effect of the flow profile on the spatial evolution of rollwave trains is then numerically investigated solving the Saint Venant equations with a second-order Runge-Kutta Total Variation Diminishing (TVD) Finite Volume scheme. The numerical simulations comply with the analytical results for the initial and transition phases of the roll-wave development. The unperturbed profile influences even the roll-waves statistical characteristics in the final stage, with a more evident effect in case of accelerated profiles. The influence of the flow profile should be therefore accounted for in the formulation of predictive criteria for roll-waves appearance based on the estimation of the disturbance spatial growth rate.