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2232. Imobilizácia rádionuklidov a kadmia v pôdach aplikáciou zeolitu
- Creator:
- Čipáková, Andrea
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- soil, sorption, distribution coefficient, cadmium, radiostrontium, radiocaesium, zeolite, pôda, sorpcia, rozdeľovací koeficient, kadmium, rádiostroncium, and rádiocézium, zeolit
- Language:
- Slovak
- Description:
- Results of cadmium sorption and desorption, as well as distribution coefficients of cadmium in the soils from the Danubian Lowland and from Veľký Ďur (neighbourhood of the nuclear power plant Jaslovske Bohunice) are presented in this study. It was found that Cd adsorption is high in studied soils already after the one-minute lasting Cd-soil contact. The results obtained show that the highest sorption of cadmium is in the loamy-sand soil from Kalinkovo (99.75 %). Zeolite application was the most effective in the loam soil from Macov. Sorption of cadmium in this soil increased by 1.45%. The presence of zeolite in chosen soil samples influenced Cd desorption, too. In loamy-sand soil from Kalinkovo cadmium desorption decreased by 50 % after zeolite application. Sorption experiments with radionuclides (85Sr and 137Cs) were conducted on brown earth from the site Velľký Ďur. The 137Cs sorption is very high in studied soil. Zeolite is more effective in the case of 85Sr. Desorption of radiostrontium decreased by 50% after zeolite application. and V práci sa prezentujú výsledky sorpcie, desorpcie a hodnoty rozdeľovacieho koeficientu kadmia vo vybraných vzorkách pôd Podunajskej nížiny a hnedozeme z lokality Veľký Ďur. Kadmium je silne sorbované sledovanými pôdami už po 1 minúte trvania kontaktu. Najvyššia sorpcia sa pozorovala u hlinito-piesočnatej pôdy z lokality Kalinkovo, kde pomerné adsorbované množstvo S kadmia bolo 99,75 %. Aplikácia zeolitu sa najviac prejavila u hlinitej pôdy z Macova, kde sa pomerné adsorbované množstvo S kadmia zvýšilo o 1,45 %. Zeolit ovplyvnil aj desorpciu naviazaného kadmia v sledovaných pôdnych vzorkách. Najviac kadmia sa desorbovalo z hlinito-piesočnatej pôdy z Kalinkova a aplikácia zeolitu znížila pomerné desorbované množstvo kadmia na menej ako polovicu. Sorpčné experimenty s rádionuklidmi (85Sr a 137Cs) boli vykonané na hnedozemi z lokality Veľký Ďur. 137Cs je už samotnou pôdou sorbované takmer na 100 % a prítomnosť zeolitu už sorpciu prakticky nezvyšuje. Zeolit zvyšuje sorpciu hlavne u rádiostroncia. Desorpcia stroncia po aplikácii zeolitu sa znížila o 50 %.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2233. Impact of armour layer on the depth of scour hole around side-by-side bridge piers under ice-covered flow condition
- Creator:
- Namaee, Mohammad Reza and Sui, Jueyi
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- armour layer, local scour, bridge pier, ice cover, non-uniform sand, and erosion of river-bed
- Language:
- Slovak
- Description:
- In the present study, experiments were conducted in a large-scale flume to investigate the issue of local scour around side-by-side bridge piers under both ice-covered and open flow conditions. Three non-uniform sediments were used in this experimental study. Analysis of armour layer in the scour holes around bridge piers was performed to inspect the grain size distribution curves and to study the impact of armour layer on scour depth. Assessments of grain size of deposition ridges at the downstream side of bridge piers have been conducted. Based on data collected in 108 experiments, the independent variables associated with maximum scour depth were assessed. Results indicate that the densimetric Froude number was the most influential parameter on the maximum scour depth. With the increase in grain size of the armour layer, ice cover roughness and the densimetric Froude number, the maximum scour depth around bridge piers increases correspondingly. Equations have been developed to determine the maximum scour depth around bridge piers under both open flow and ice covered conditions.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
2234. Impact of conservation practices on runoff and soil loss in the sub-humid Ethiopian Highlands: the Debre Mawi watershed
- Creator:
- Dagnew, Dessalegn C., Guzman, Christian D., Zegeye, Assefa D., Tibebu, Tigist Y., Getaneh, Menelik, Abate, Solomon, Zemale, Fasikaw A., Ayana, Essayas K., Tilahun, Seifu A., and Steenhuis, Tammo S.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- runoff, soil loss, sediment concentration, Blue Nile basin, and soil and water conservation
- Language:
- Slovak
- Description:
- In response to the continually increasing sediment concentrations in rivers and lakes, the Ethiopian government is leading an effort where farmers are installing soil and water conservation measures to increase infiltration and reduce erosion. This paper reports on findings from a four year study in the 95 ha Debre Mawi watershed where under the government led conservation works, mainly terraces with infiltration furrows were installed halfway in the period of observation. The results show that runoff volume decreased significantly after installation of the soil and water conservation practices but sediment concentration decreased only marginally. Sediment loads were reduced mainly because of the reduced runoff. Infiltration furrows were effective on the hillsides where rain water could infiltrate, but on the flat bottom lands that become saturated with the progress of the monsoon rain, infiltration was restricted and conservation practices became conduits for carrying excess rainfall. This caused the initiation of gullies in several occasions in the saturated bottomlands. Sediment concentration at the outlet barely decreased due to entrainment of loose soil from unstable banks of gullies in the periodically saturated bottom areas. Since most uphill drainage were already half filled up with sediments after two years, long term benefits of reducing runoff can only be sustained with continuous maintenance of uphill infiltration furrows.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2235. Impact of evapotranspiration on discharge in small catchments
- Creator:
- Dvořáková, Šárka, Kovář, Pavel, and Zeman, Josef
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- catchment water depletion, diurnal streamflow variability, evapotranspiration, and Linear Storage Model (LSM)
- Language:
- Slovak
- Description:
- We apply the Linear Storage Model (LSM) to simulate the influence of the evapotranspiration on discharges. High resolution discharge data from two small catchments in the Czech Republic, the Teply Brook and the Starosuchdolsky Brook catchment are used. The results show the runoff process is simpler in a deeper valley of the Starosuchdolsky catchment where the soil zone is deeper and the valley bottom recharges runoff even during very dry periods. Two-soil zone model is adequate to simulate the diurnal runoff variability. Three-soil zone model is needed in the Teply Brook catchment due to the absence of water transport in the most-upper soil zone. Time delays between minimum and maximum discharge during the day reach up to about 20 hours. Evapotranspiration and hydraulic resistances are as high as 14% of catchment daily runoff in the urbanized Starosuchdolsky Brook catchment and 25% of catchment daily runoff in the forested, less impacted Teply Brook catchment.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2236. Impact of reconfiguration on the flow downstream of a flexible foliated plant
- Creator:
- Maio, Marco, Marini, Gustavo, Fontana, Nicola, Gualtieri, Paola, and Caroppi, Gerardo
- Format:
- počítač and online zdroj
- Type:
- model:article and TEXT
- Subject:
- flow-vegetation interaction, riparian vegetation, plant reconfiguration, leaf morphology, turbulence, particle image velocimetry, and acoustic Doppler velocimetry
- Language:
- Slovak
- Description:
- This paper explores the impacts of reconfiguration and leaf morphology on the flow downstream of a flexible foliated plant. 3D acoustic Doppler velocimetry and particle image velocimetry were used to experimentally investigate the hydrodynamic interaction between a foliated plant and the flow, testing two plants with different leaves morphology under different bulk flow velocities. The model vegetation was representative of riparian vegetation species in terms of plants hydrodynamic behavior and leaf to stem area ratio. To explore the effects of the seasonal variability of vegetation on the flow structure, leafless conditions were tested. Reconfiguration resulted in a decrease of the frontal projected area of the plants up to the 80% relative to the undeformed value. Such changes in plant frontal area markedly affected the spatial distributions of mean velocity and turbulence intensities, altering the local exchanges of momentum. At increasing reconfiguration, the different plant morphology influenced the mean and turbulent wake width. The leafless stem exhibited a rigid behavior, with the flow in the wake being comparable to that downstream of a rigid cylinder. The study revealed that the flexibility-induced reconfiguration of plants can markedly affect the local distribution of flow properties in the wake, potentially affecting transport processes at the scale of the plant and its subparts.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2237. Impact of secondary succession in abandoned fields on some properties of acidic sandy soils
- Creator:
- Lichner, Ľubomír, Iovino, Massimo , Šurda, Peter, Nagy, Viliam, Zvala, Anton, Kollár, Jozef, Pecho, Jozef, Píš, Vladimír, Sepehrnia, Nasrollah, and Sándor, Renáta
- Format:
- počítač and online zdroj
- Type:
- model:article and TEXT
- Subject:
- water repellency, acidic sandy soil, land abandonment, secondary succession, and soil properties
- Language:
- Slovak
- Description:
- Abandonment of agricultural lands in recent decades is occurring mainly in Europe, North America and Oceania, and changing the fate of landscapes as the ecosystem recovers during fallow stage. The objective of this study was to find the impact of secondary succession in abandoned fields on some parameters of acidic sandy soils in the Borská nížina lowland (southwestern Slovakia). We investigated soil chemical (pH and soil organic carbon content), hydrophysical (water sorptivity, and hydraulic conductivity), and water repellency (water drop penetration time, water repellency cessation time, repellency index, and modified repellency index) parameters, as well as the ethanol sorptivity of the studied soils. Both the hydrophysical and chemical parameters decreased significantly during abandonment of the three investigated agricultural fields. On the other hand, the water repellency parameters increased significantly, but the ethanol sorptivity did not change during abandonment. As the ethanol sorptivity depends mainly on soil pore size, the last finding could mean that the pore size of acidic sandy soils did not change during succession.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
2238. Impact of soil compaction on water content in sandy loam soil under sunflower
- Creator:
- Nagy, Viliam, Šurda, Peter, Lichner, Ľubomír, Kovács, Attila J., and Milics, Gábor
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- soil compaction, soil penetration resistance, bulk density, and water flow
- Language:
- Slovak
- Description:
- Soil compaction causes important physical modifications at the subsurface soil, especially from 10 to 30 cm depths. Compaction leads to a decrease in infiltration rates, in saturated hydraulic conductivity, and in porosity, as well as causes an increase in soil bulk density. However, compaction is considered to be a frequent negative consequence of applied agricultural management practices in Slovakia. Detailed determination of soil compaction and the investigation of a compaction impact on water content, water penetration depth and potential change in water storage in sandy loam soil under sunflower (Helianthus annuus L.) was carried out at 3 plots (K1, K2 and K3) within an experimental site (field) K near Kalinkovo village (southwest Slovakia). Plot K1 was situated on the edge of the field, where heavy agricultural equipment was turning. Plot K2 represented the ridge (the crop row), and plot K3 the furrow (the inter–row area of the field). Soil penetration resistance and bulk density of undisturbed soil samples was determined together with the infiltration experiments taken at all defined plots. The vertical bulk density distribution was similar to the vertical soil penetration resistance distribution, i.e., the highest values of bulk density and soil penetration resistance were estimated at the plot K1 in 15–20 cm depths, and the lowest values at the plot K2. Application of 50 mm of water resulted in the penetration depth of 30 cm only at all 3 plots. Soil water storage measured at the plot K2 (in the ridge) was higher than the soil water storage measured at the plot K3 (in the furrow), and 4.2 times higher than the soil water storage measured at the most compacted plot K1 on the edge of the field. Results of the experiments indicate the sequence in the thickness of compacted soil layers at studied plots in order (from the least to highest compacted ones): K2–K3–K1.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
2239. Impact of the entrapped air on water flow and solute transport in heterogeneous soil: experimental set-up
- Creator:
- Sněhota, Michal, Sobotková, Martina, and Císlerová, Milena
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- entrapped air, infiltration experiment, undisturbed soil sample, breakthrough curve, preferential flow, uzavřený vzduch, infiltrační experiment, neporušený půdní vzorek, průniková čára, and preferenční proudění
- Language:
- Slovak
- Description:
- Changes of steady state water flow rates and the bromide breakthrough were observed in laboratory infiltration experiments done on a sample of compacted sand and on an undisturbed soil sample (Eutric Cambisol). Infiltration-outflow experiments consisted of series of ponded infiltration runs with seepage face boundary condition at the lower end of columns. The initial water contents were different for each run. The results of the experiment done on an undisturbed soil column showed that the flux rates and water contents measured during quasi-steady state differ between infiltration runs. This finding contradicts the standard theory. The fluctuations of the water content during the steady state flow can be ascribed to the variations in volume of the entrapped air. Similarly, bromide breakthrough curves performed during the steady state flow runs differ for the undisturbed soil sample. The same behaviour was not observed in the sample of homogeneous sand. Computer tomography was utilized to characterize the structure of the undisturbed soil sample with focus on potential preferential flow pathways. To formulate more general conclusions, the infiltration outflow and bromide solute transport experiments have to continue with the aim to collect a representative set of data. and Studie sleduje změny ustálených rychlostí proudění a průnikových čar bromidu na vzorku zhutněného písku a na neporušeném vzorku půdy ze skupiny kambisolů. Experimenty sestávaly ze série výtopových infiltrací na horním okraji a s výronovou plochou na spodním okraji vzorků. Počáteční vlhkost byla pro jednotlivé infiltrační běhy různá. Výsledky experimentu uskutečněného na neporušené půdě ukazují, že se vlhkosti a rychlosti proudění během ustáleného proudění lišily pro jednotlivé infiltrační běhy. Tento efekt není ve shodě se standardní teorií. Změny vlhkosti během ustáleného proudění mohou být způsobeny přítomností uzavřeného vzduchu. Pro neporušený půdní vzorek se lišil také tvar průnikových čar bromidu, měřených během ustáleného proudění. Oba efekty nebyly pozorovány pro vzorek zhutněného písku. Počítačová tomografie byla použita k popisu struktury neporušeného půdního vzorku se zaměřením na přítomnost potenciálních cest preferenčního proudění. K tomu, aby bylo možno formulovat obecné závěry, bude nutné získat reprezentativní soubor dat pomocí zde představeného experimentu.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2240. Impacts of bridge piers on the initiation of ice cover - an experimental study
- Creator:
- Wang, Jun, Shi, Fayi, Chen, Pangpang, Wu, Peng, and Sui, Jueyi
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- arch-shaped congestion, bridge pier, ice cover, ice floe concentration, and pier distance
- Language:
- Slovak
- Description:
- Ice jams in northern rivers during winter period significantly change the flow conditions due to the extra boundary of the flow. Moreover, with the presence of bridge piers in the channel, the flow conditions can be further complicated. Ice cover often starts from the front of bridge piers, extending to the upstream. With the accumulation of ice cover, ice jam may happen during early spring, which results in the notorious ice jam flooding. In the present study, the concentration of flowing ice around bridge piers has been evaluated based on experiments carried out in laboratory. The critical condition for the initiation of ice cover around bridge piers has been investigated. An equation for the critical floe concentration was developed. The equation has been validated by experimental data from previous studies. The proposed model can be used for the prediction of formation of ice cover in front of a bridge pier under certain conditions.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public