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782. Lesnicko-hydrologický výzkum v beskydských experimentálních povodích
- Creator:
- Bíba, Milan, Oceánská, Zuzana, Vícha, Zdeněk, and Jařabáč, Milan
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- precipitations and outflows in the Beskydy Mts., two experimental basins, 52-year long time series of measurement, forest renewal, air pollution, srážky a odtoky v Beskydech, dvě experimentální povodí, 52-leté řady měření, obnovy porostů, and znečišťování ovzduší
- Language:
- Slovak
- Description:
- Forests are an important factor to control outflows of water and also partly prevent dangerous floods. In November 1927 two small representative basins with a great difference of percentages of forest cover were set up in the Czechoslovakia to measure precipitations and ouflows during 30 years with the following forest renewal. In 1953 two small fully forested experimental basins were set up with the concept to prove the increase of water resources by forest management. After a 12 year-long calibration period the accelerated forest renewal started. Both experimental basins were better accessed by forest roads. Analyses of data fluently recorded till now show that the relationship of precipitations and runoffs depends more on natural impulses than on management methods of forests. The great scatter of climatic impulses overwhelms the consequences of methods of forest management in both basins. An important factor of outflows of water is the capacity of water retention in forest soils (around 50 mm in this area). Flood and erosion control functions of the forests become to be evident but only in a limited way. The intensity of erosion in experimental basins is effectively dampened by woods and plants. and Lesy jsou důležitým faktorem při sledování odtoků vody a částečnou prevencí proti nebezpečným povodním. V listopadu 1927 byla započata třicetiletá měření srážek a odtoků ve dvou representativních povodích s velkým rozdílem v pokrytí lesem, s následujícími lesnickými obnovami. V roce 1953 se započalo měřit ve dvou malých, plně lesnatých experimentálních povodích s důvodem ověřit přibývání vody při lesnickém hospodaření. Po dvanáctileté kalibrační době začala zrychlená lesnická obnova. Obě experimentální povodí byla lépe zpřístupněna lesními cestami. Rozbor plynule zaznamenaných dat až do teď ukazuje, že vztah srážek a odtoků je více závislý na přírodních podnětech než na metodách hospodaření. Velký rozptyl klimatických prvků překonává důsledek hospodaření v obou povodích. Důležitým faktorem odtoků vody je kapacita vodní retence lesních půd (v těchto podmínkách asi 50 mm). Protipovodňové a protierozní funkce lesů jsou evidentní, ale omezené. Intenzita eroze v experimentálních povodích je efektivně tlumena stromy a rostlinami.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
783. Limitations of non-Gricean approaches to the evolution of human communicative abilities
- Creator:
- Włodarczyk, Mateusz
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- evolution of communication, evolution of language, expressive communication, Gricean communication, and organic meaning
- Language:
- Slovak
- Description:
- In this paper, I examine two non-Gricean approaches to the evolution of human communicative abilities: Mitchell S. Green’s ac- count of organic meaning and Dorit Bar-On’s account of expressive communication. I argue that the non-Gricean approaches in question face certain problems: i) they focus on the adaptive function of communicative behaviours and ignore questions about their mechanisms, ontogeny and phylogeny; ii) the notion of organic meaning does not constitute an intermediate form between natural and non-natural meaning but should rather be understood as a special case of natural meaning; iii) the non-Gricean approaches under scrutiny cannot ex- plain the transition from dyadic to triadic communication. I also outline the differences between Gricean and non-Gricean approaches and argue against the usefulness of the non-Gricean approaches discussed in this paper in explaining the evolution of human communicative abilities.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
784. Linear stability analysis reveals exclusion zone for sliding bed transport
- Creator:
- Talmon, Arnold M.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- stratification, hydrotransport, transients, and bed layer
- Language:
- Slovak
- Description:
- A bend or any another pipe component disturbs solids transport in pipes. Longitudinal pressure profiles downstream of such a component may show a stationary transient harmonic wave, as revealed by a recent settling slurry laboratory experiment. Therefore the fundamental transient response of the two-layer model for fully stratified flow is investigated as a first approach. A linear stability analysis of the sliding bed configuration is conducted. No stationary transient harmonic waves are found in this analysis, but adaptation lengths for exponential recovery are quantified. An example calculation is given for a 0.1 m diameter pipeline. Also consequences for long stretches of pipe line emerged. A so far undiscovered exclusion zone is found in the I-V diagram. This exclusion zone is situated adjacent to the deposit limit velocity locus curve. This simplified physical system reveals that flow velocities should be taken about 10% greater than the calculated maximum deposit limit velocity for stable converging flow.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
785. Linkage between in-stream total phosphorus and land cover in Chugoku district, Japan: an ann approach
- Creator:
- Amiri, Bahman Jabbarian, Sudheer, K. P., and Fohrer, Nicola
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- water quality modeling, land use, total phosphorus, ANN, uncertainty analysis, modelovanie kvality vody, využívanie krajiny, celkový obsah fosforu, and analýza neurčitosti
- Language:
- Slovak
- Description:
- Development of any area often leads to more intensive land use and increase in the generation of pollutants. Modeling these changes is critical to evaluate emerging changes in land use and their effect on stream water quality. The objective of this study was to assess the impact of spatial patterns in land use and population density on the water quality of streams, in case of data scarcity, in the Chugoku district of Japan. The study employed artificial neural network (ANN) technique to assess the relationship between the total phosphorous (TP) in river water and the land use in 21 river basins in the district, and the model was able to reasonably estimate the TP in the stream water. Uncertainty analysis of ANN estimates was performed using the Monte Carlo framework, and the results indicated that the ANN model predictions are statistically similar to the characteristics of the measured TP values. It was observed that any reduction in forested area or increase in agricultural land in the watersheds may cause the increase of TP concentration in the stream. Therefore, appropriate watershed management practices should be followed before making any land use change in the Chugoku district. and Rozvoj územia často súvisí so zintenzívnením využívania krajiny a produkciou znečistenia. Dôležité je modelovanie týchto zmien a ich vplyvu na kvalitu vody v tokoch. Cieľom štúdie je určiť vplyv priestorových zmien pri využívaní krajiny a zmeny hustoty osídlenia na kvalitu vody v tokoch v čase nedostatku vody v oblasti Chugoku, Japonsko. Pri riešení sa využívajú umelé neurónové siete (artificial neural network -ANN), prostredníctvom ktorých sa určuje vzťah medzi celkovým obsahom fosforu (TP) v toku a využívaním kajiny v 21 povodiach oblasti; tento model je schopný vypočítať TP v tokoch. Analýza neurčitosti výsledkov dosiahnutých pomocou ANN bola vykonaná metódou Monte Carlo; výsledky analýzy naznačujú, že predpovede pomocou metódy ANN sú štatisticky podobné meraným hodnotám TP. Bolo zistené, že redukcia lesnatosti a zvýšenie plochy poľnohospodársky využívanej pôdy v povodí môže viesť k zvýšeniu koncentrrácie TP v toku. Je preto potrebné pred zmenou vo využívaní krajiny prijať zodpovedajúce opatrenia v manažmente krajiny, ktoré budú minimalizovať negatívne dôsledky zmien využívania krajiny.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
786. Linking surface and subsurface properties of biocrusted and non-biocrusted habitats of fine-grained fluvial sediments (playas) from the Negev Desert
- Creator:
- Kidron, Giora J.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- available water content, loess, and soil moisture
- Language:
- Slovak
- Description:
- With biocrusts playing a cardinal role in C and N fixation in arid zones, information regarding the factors that determine their limits of growth is of uttermost importance for the study of ecosystem structure and function. This is also the case in the western Negev dunefields, where although abundant on the sandy surfaces, biocrusts are scarce on finegrained (mainly loessial) sediments, termed playas. In the Nizzana research site (NRS), visibly distinct surfaces, with and without biocrusts were noted within a single playa. In an attempt to characterize these distinct surfaces, a set of random measurements were carried out, which included measurements of crack density, microrelief and chlorophyll content of the upper 0-1 cm. Following a cluster analysis, four distinct types of surfaces (hereafter habitats) were defined, one with substantial amount of chlorophyll content which can be regarded as biocrust (P4), and three non-crusted surfaces (P1- P3). Within each type, two 50 cm-deep pits were dug and the pH, electrical conductivity (EC) and fine (silt and clay) content (FC) of samples collected at 1-5, 5-10, 10-20, 20-30, 30-40 and 40-50 cm-depth were analyzed. In addition, periodical moisture measurements were carried out (in pairs) to a depth of 0-20 cm at each surface type during 2013/14. All non-crusted habitats (P1-P3) were characterized by loessial subsurface sediments. Conversely, P4 was either characterized by loessial subsurface sediments (and in this case it was characterized by a slightly concave surface) or having a sandy subsurface (at ~5-10 cm depth). While the non-crusted surfaces exhibited low moisture content, P4 exhibited deeper and higher moisture content explained either by the more sandy sediments or by lower water loss through runoff. The findings point to the close link between surface and subsurface properties and indicate that water availability may explain biocrust establishment and growth also at the loessial playa surfaces. Biocrusts may thus serve as bioindicators for habitats with high moisture content.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
787. Local head loss in plastic pipeline joint welded by butt fusion
- Creator:
- Melichar, Jan, Háková, Jaroslava, Veselský, Jaroslav, and Michlík, Luboš
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- local loss, frictional loss, plastic pipelines, místní ztráta, ztráta třením, and plastové potrub
- Language:
- Slovak
- Description:
- The article deals with experimental determination of local head loss in straight polypropylene pipeline (PP) joint connected by butt-welding. A local loss coefficient is introduced for turbulent flow of water in plastic pipeline of circular cross-section. The value of local loss coefficient has not been experimentally quantified so far and hence its determination is significant for designers of plastic pipeline systems. and Článek pojednává o experimentálním stanovení místní ztráty ve spoji přímého potrubí z polypropylenu (PP), zhotoveného svařováním na tupo. Je uvedena velikost součinitele místní ztráty spoje plastového potrubí kruhového průřezu při turbulentním proudění čisté vody. Místní ztráta doposud nebyla experimentálně kvantifikována, a proto je její stanovení pro projektanty potrubních systémů z plastů významné.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
788. Local scour around complex pier groups and combined piles at semi-integral bridge
- Creator:
- Akib, Shatirah, Jahangirzadeh, Afshin, and Basser, Hossein
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- semi-integral bridge, complex pier groups, combined piles, scour, pier, and scour depth
- Language:
- Slovak
- Description:
- This research presents an experimental study on the scouring mechanism at semi-integral bridge piers. Based on laboratory experiments, this study focuses on the relationship between scour depth in complex pier groups and combined piles bridge and various parameters including the variation of inflow velocity, distance, and time. 1 200 data were collected for flow velocity and scour. The flow pattern and scour were analyzed for different flow discharges and flow depths. The results showed that the scour development with respect to time was greater for higher flow depth and bigger flow discharge at semi-integral bridges. In addition, the equilibrium scour depth increased with the approach flow depth around piers at semi-integral bridges. Velocity distribution also affected the scour development. It decreased when approaching the bridge but increased from upstream to downstream of the flume.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
789. Long-term hydrometeorological measurements and model-based analyses in the hydrological research catchment Rietholzbach
- Creator:
- Gurtz, Joachim, Verbunt, Mark, Zappa, Massimiliano, Moesch, Michael, Pos, Femke, and Moser, Ulrich
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- hydrological research catchments, water balance, precipitation correction, hydrological modelling, lysimeter, výskumné hydrologické povodia, hydrologická bilancia, oprava zrážok, hydrologické modelovanie, and lyzimeter
- Language:
- Slovak
- Description:
- In this study a 25-year (1976-2000) series of observed precipitation, temperature, runoff and further water-flows of a lysimeter balance within the pre-alpine research catchment Rietholzbach (Switzerland) is analyzed. The comparison of the precipitation volumes on this lysimeter to precipitation collected by a conventional rain gauge shows that conventional rain gauges provide strongly underestimated values for precipitation, especially in winter. The obtained monthly precipitation correction factors indicate that precipitation losses above 20% for rain and above 50% for snow are realistic. The observed hydrometeorological values allowed for improving the understanding of the model-based simulation of the hydrological processes with distributed hydrological models and for investigating both a conceptual and a physically based runoff-generation approach. The albedo, soil moisture and lysimeter water balance allowed for a simultaneous assessment of the performance of several model components, such as the soil moisture, runoff-generation and evapotranspiration modules and the module for the determination of snow cover accumulation and melt. and V príspevku sú analyzované 25-ročné rady zrážok, teploty vzduchu, odtoku a hydrologickej bilancie v lyzimetri vo výskumnom povodí Rietholzbach (Švajčiarsko). Porovnanie zrážok zachytených lyzimetrom a konvenčným zrážkomerom ukazuje, že údaje zo zrážkomera sú veľmi podhodnotené, najmä v zime. Podľa získaných mesačných koeficientov opráv zrážok sú straty zrážok vyše 20 % pre dážď a vyše 50 % pre sneh realistické. Pozorované meteorologické údaje umožnili lepšie pochopiť simuláciu hydrologických procesov pomocou distribuovaných hydrologických modelov a pomohli pri posudzovaní konceptuálneho aj fyzikálne založeného prístupu k modelovaniu tvorby odtoku. Albedo, vlhkosť pôdy a hydrologická bilancia lyzimetra umožnili posúdiť funkciu niekoľkých zložiek modelu (moduly vlhkosti pôdy, tvorby odtoku, evapotranpirácie a akumulácie a topenia snehu).
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
790. Long-term soil water content dynamics under different land uses in a small agricultural catchment
- Creator:
- Horel, Ágota, Zsigmond, Tibor, Molnár, Sándor, Zagyva, Imre, and Bakacsi, Zsófia
- Format:
- počítač and online zdroj
- Type:
- model:article and TEXT
- Subject:
- forest, grassland, soil water regime, vineyard, and climate change
- Language:
- Slovak
- Description:
- Longer term monitoring of soil water content at a catchment scale is a key to understanding its dynamics, which can assist stakeholders in decision making processes, such as land use change or irrigation programs. Soil water monitoring in agriculturally dominated catchments can help in developing soil water retention measurements, for assessment of land use change, or adaptation of specific land management systems to climate change. The present study was carried out in the Pannonian region (Upper-Balaton, Hungary) on Cambisols and Calcisols between 2015 and 2021. Soil water content (SWC) dynamics were investigated under different land use types (vineyard, grassland, and forest) at three depths (15, 40, and 70 cm). The meteorological data show a continuous decrease in cumulative precipitation over time during the study with an average of 26% decrease observed between 2016 and 2020, while average air temperatures were similar for all the studied years. Corresponding to the lower precipitation amounts, a clear decrease in the average SWC was observed at all the land use sites, with 13.4%, 37.7%, and 29.3% lower average SWC for the grassland, forest, and vineyard sites, respectively, from 2016 to 2020 (measured at the 15 cm depth of the soil). Significant differences in SWC were observed between the annual and seasonal numbers within a given land use (p < 0.05). The lowest average SWC was observed at the grassland (11.7%) and the highest at the vineyard (28.3%). The data showed an increasing average soil temperature, with an average 6.3% higher value in 2020 compared to 2016. The grassland showed the highest (11.3 °C) and the forest soil the lowest (9.7 °C) average soil temperatures during the monitoring period. The grassland had the highest number of days with the SWC below the wilting point, while the forest had the highest number of days with the SWC optimal for the plants.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public