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EN
The design process in geotechnical engineering requires the most accurate mapping of soil. The difficulty lies in the spatial variability of soil parameters, which has been a site of investigation of many researches for many years. This study analyses the soilmodeling problem by suggesting two effective methods of acquiring information for modeling that consists of variability from cone penetration test (CPT). The first method has been used in geotechnical engineering, but the second one has not been associated with geotechnics so far. Both methods are applied to a case study in which the parameters of changes are estimated. The knowledge of the variability of parameters allows in a long term more effective estimation, for example, bearing capacity probability of failure.
EN
The spatial distribution of the radiant heating rate (RHR) in an area of seawater absorption change was investigated by means of a theoretical model. It was found that a sufficiently high gradient of the absorption coefficient in a horizontal direction could contribute significantly to the water’s warming. When combined with an absorption increase in the vertical direction, it raised the local RHR value to about one and a half times its value in the adjacent area. Moreover, when solar energy propagated through the water of higher absorption and entered the area of lower absorption, the horizontal component of the absorption gradient resulted in a lowering of the RHR value. The highest obtained spatial differences between the radiant heating rate values was of the order of 10-2 oC per hour under the conditions of a cloudless sky with the sun zenith angle at 45o and sea surface irradiance value of nearly 700 W m-2.
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Content available Soil Sequences Along a Slope of the Opalenica Plain
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EN
The paper presents the results of a study on differentiation of the morphological structure of soil and selected physical and chemical properties of soils in toposequence of the Opalenica Plain. The study was conducted in a 1200 m long transect running through a typical soil toposequence for the Polish Lowland, and therefore the results presented in this study can be extrapolated to similar geomorphological conditions of the area. On the basis of pedological cross-section, the following soil units were distinguished: PWspgl – Albic Luvisols (Arenic) with glossic properties, PAt – Albic Glossic Retisols (Loamic), PAsp – Albic Glossic Retisols (Aric, Arenic), PAspgg – Albic Glossic Retisols (Aric, Arenic, Oxyaquic), PWsggl – Albic Luvisols (Aric, Arenic, Stagnic) with glossic properties, PWgggl – Albic Luvisols (Aric, Loamic, Stagnic) with glossic properties, CZgg – Mollic Reductigleyic Eutric Gleysols (Aric, Loamic), CFt – Fluvic Phaeozems (Aric, Arenic). Each of these units has its own specific position in toposequence but the occurrence of Fluvic Phaeozems (Aric, Arenic) are associated with geogenetic processes of Mogilnica river. In this work, using a multiple regression analysis a statistically significant relationships between the position of the soils in relief and the terrain slopes and the organic carbon content in Ap horizon, the cation exchangeable capacity, the sum of exchangeable bases and the pH were obtained. Systematic variability of most soil properties of Ap horizon have shown two distances of spatial variation. The first concerns the systematic changes in shorter distance (from 132 to 344 m) and can be associated with differences in soil properties between separate soil units. The second distance of spatial correlation ranges from 431 m to 792 m, which testify to the fact that quantitative changes in the properties of soils are realized gradually and distinctly, together with the differentiation of the slope, over several separate cartographic units.
EN
The result of geomechanical and hydrological degradation caused by the underground extraction of hard coal are the transformations of the environmentally managed terrains and high variability of soil properties occurring in these areas. The analysis of selected soil properties of spatial variability in the post-mining area conducted by means of the kriging technique was presented in the paper. The determined points of empirical semivariogram were described by means of mathematical functions and theoretical semivariograms were plotted. The conducted analysis allowed to plot the maps of variability isolines, which my provide a basis to delineate the boundaries of areas most susceptible to the hydrological degradation of soils. The obtained research results indicate that the applied kriging technique may prove to be a useful tool for determining spatial variability of soils in the areas of hard coal mining operations and allow to delineate the boundaries of the areas most susceptible to soil degradation.
EN
The phenomenon of erosion on mountain and submontane areas influences directly on high variability of soil properties. In the work there were presented results of analysis of spatial variability of bulk density, total porosity, organic matter content and saturated hydraulic conductivity, on eroded slopes of the Kasińczanka stream basin. Geostatistical analysis was carried out using the kriging method, based on irregular network, consisted of 52 points, situated by means of the GPS. Taking into account the calculated variability coefficient it was stated, that on the investigated area, the most flexible spatially was saturated hydraulic conductivity, while the less flexible turned out total porosity. Using the determined models of semivariance, the maps of spatial variability of chosen parameters were drafted. It was stated that high value of variance influenced on higher smoothing of spatial distribution in interpolation. Results of geostatistical analysis will allow to find locations for new measuring points, what has substantial significance in mountain areas, for precision analysis of soil properties. Based on the obtained results, it can be stated that the kriging method may be useful tool for determination spatial variability analysis of soil properties on an areas of mountain basins.
EN
Low-flows are an important component of the river regime. Their identification advances our knowledge about the formation of water resources in drought conditions. The analyses that we have carried out aimed to indicate the spatial structure of these flows. Our study area was the Warta River catchment up to the water-gauge at Sieradz. The input research material consisted of a sequence of daily discharge data for 12 gauging stations located in this catchment, in the period of 1971-2000, made available by IMGW-PIB. At the first stage, periodic flows based on flow time-duration curve and annual minimum flows were determined. Their values have been converted into specific flows, which facilitated the conduct of comparative analyses. On the basis of the obtained results, the spatial variability of low-flows in studied catchment was evaluated. The annual number of days with low-flows was identified for all gauge sections. The dynamics and distribution of low flow appearing in the multiannual period were evaluated. The analyses we have carried out made it possible to identify the factors, which determine the structure of low-flows. Research results have been illustrated with relevant maps and graphs.
PL
Przepływy niżówkowe stanowią ważny element reżimu rzecznego. Ich rozpoznanie poszerza wiedzę o kształtowaniu się zasobów wodnych w warunkach suszy. Przeprowadzone analizy miały na celu ocenę przestrzennej struktury tych przepływów. Obszarem badań była zlewnia Warty po wodowskaz w Sieradzu. Wejściowy materiał badawczy stanowiły serie przepływów dobowych z okresu 1971–2000 dla 12 wodowskazów zlokalizowanych w tej zlewni, udostępnione przez IMGW-PIB. W pierwszym etapie wyznaczono przepływy okresowe na bazie krzywej czasów trwania wraz z wyższymi oraz roczne przepływy minimalne. Ich wartości zostały przeliczone na odpływy jednostkowe, dzięki czemu możliwe były analizy porównawcze. Na podstawie uzyskanych wyników dokonano oceny przestrzennej zmienności przepływów niżówkowych w badanej zlewni. Dla wszystkich przekrojów zidentyfikowano roczną liczbę dni z przepływem niżówkowym. Ocenie poddano także dynamikę i rozkłady minimów przepływu, pojawiających się w okresie wieloletnim. Przeprowadzone analizy pozwoliły na wyodrębnienie czynników decydujących o strukturze przepływów niżówkowych. Wyniki badań zostały zilustrowane na stosownych mapach i wykresach.
EN
The article examines how different social and urban processes were reflected in the spatial patterns of three dimensions of population structure (demographic, socio-economic, and ethnic statuses) in Prague during the socialist and post-socialist periods. The article has three main objectives. First, it analyses inertia and change in socio-spatial patterns and evaluates the processes that have influenced them. Second, it investigates how the importance of all three statuses in the spatial differentiation of urban space has evolved. Third, the article focuses on the level of geographical variability as recorded within different spatial scales, and the development of this variability. It examines selected indicators of socio-economic, demographic, and ethnic statuses by employing detailed statistical data on the level of basic settlement units from the Population Censuses held in 1970, 1991, and 2011. The results confirm that the most significant changes in socio-spatial patterns between socialism and post-socialism can be observed for ethnic spatial differentiation. In addition, the city witnessed considerable changes in demographic spatial patterns in both periods, while socio-economic spatial patterns have remained relatively stable. New socio-spatial processes driven predominantly by movements of young and better-off populations have taken place in previously less attractive neighbourhoods. As a result, very different populations often live side-by-side in contemporary Prague.
EN
Effects of spatial fluctuations of soil parameters are considered in a new context – considering variability of soil parameters in conjunction with non-uniform stress fields, which can locally amplify (or suppress) subsoil inhomogeneities. In this way, several design situations for the Coulomb frictional material with random tan(φ(x)) reveal a reduction of variance, which is less significant than for the standard volume averaging. When looking for an 'effective' random variable [tan(φ)]a – that is, a random variable, which is equivalent to the random field tan(φ(x)) – the Vanmarcke averaging by simple volume integrals is insufficient; it systematically overestimates effects of variance reduction, thus causing potentially unsafe situations. The new proposed approach is coherent, formally defined and more realistic.
EN
Precipitation is a component of the hydrological cycle, knowing its spatial distribution is vital for the management of hydrographic basins, the territory and the development of fundamental activities for society. That is why the present study shows the spatial variability of rainfall in Cartagena de Indias city with a network of rain gauges, made up of nine pieces of equipment, separated from each other by 0.9-27 km. After a year of recording (2019), using historical series of data, it was found that the maximum rainfall occurs in the trimester between September and November, with interpolated maps made by the Ordinary Kriging (OK) method it was found that the maximum rainfall is focused on the north, centre and west of the territory, instead, the maximum intensities are presented in the centre and west, the minimums for both variables are presented to the east and south. The 70 and 90% of the rain events have a duration of less than 30 min and 1 h, respectively. Three-parameter exponential function was fitted to the paired correlation distances, and presented correlations lower than 0.8, 0.5 and 0.2 from distances of 1, 3 and 7 km, respectively, in 30 min rain integration. It was also found that with a pluviometric network conformed by at least six pieces of equipment and separated by a 5 km distance from each other in the urban area, a correlation of 0.5 and compliance with the WMO recommendations would be obtained.
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70%
EN
This paper presents the effects of soil layering on the characteristics of basin-edge induced surface waves and associated strain and aggravation factor. The simulated results revealed surface wave generation near the basin-edge. The first mode of induced Love wave was obtained in models having increasing velocity with depth and a large impedance contrast between the soil layers. Amplitude amplification or de-amplification of body waves was proportional to the impedance contrast between the soil layers. The average aggravation factor was inversely proportional to the impedance contrast between the soil layers in case of increasingvelocity models and proportional in case of decreasing-velocity basinedge models. On the other hand, the maximum strain was inversely proportional to the impedance contrast between the soil layers in both cases. On the average, strain was greater in case of increasing-velocity models but the average aggravation factor was greater in case of decreasingvelocity models.
EN
Potential activity of hydrolytic microbial extracellular enzymes were determined in a sandy beach in Sopot, (Southern Baltic Sea) in July 2001. Among of the five monitored enzymes, the highest level of activity (314.28 nM MCA g⁻¹d.w. h⁻¹) was determined in the aminopeptidase whereas chitinase had the lowest level (0.50 nM MUF g⁻¹d.w. h⁻¹) of potential activity. Usually, the ranking of the activity rates of the assayed enzymes was following: aminopeptidase > lipase > β-glucosidase > α-glucosidase > chitinase. Clear gradients in the level of enzymatic activity were determined in horizontal profile of the beach. The maximum activity of studied enzymes was recorded in sand collected under seawater and at the waterline.
PL
W artykule przedstawiono wyniki badań modelowych dotyczących wpływu dynamicznych cech opadów deszczowych na działanie systemów kanalizacyjnych. Model zlewni (10 zlewni cząstkowych o powierzchni 24ha każda) i sieci kanalizacyjnej wykonano przy użyciu programu SWMM5. W sumie przeprowadzono 126 symulacji hydrodynamicznych dla zmiennych wartości czasu trwania opadu, natężenia deszczu oraz prędkości i kierunku przesuwania się opadu nad zlewnią. Uzyskane wyniki pozwalają stwierdzić że zarówno kierunek jak i prędkość przesuwania się opadu mają duży wpływ na występujące w kanałach szczytowe natężenia przepływu. Dla opadów krótkotrwałych, przemieszczających się nad zlewnią w kierunku zgodnym z kierunkiem przepływu ścieków w kanalizacji, obliczone natężenia szczytowe były większe o ponad 100% od przepływów obliczonych dla warunków statycznych.
EN
The papers presents results of the investigations focused on dynamic properties of a rainfall events. Influence of rainfall movement on the urban drainage system performance is poorly described in a literature, so methods used by engineers don't consider the spatial variability of the rainfalls. The main source of the rainfall data for investigations was the Intensity-Duration-Frequency (IDF) curves carried out by Institute of Meteorology and Water Management. Model of virtual catchment, divided in 10 unit subcatchemnts (24ha each), was done using widely-known software EPA SWMM5. Overall, 126 hydrodynamic simulations were done, considering the variable values of the rainfall duration, intensity (based on a return period), direction and speed of rainfall movement over the catchment (2-10 m/s). Obtained results allow to formulae the conclusion that both: direction and speed of the rainfall have significant influence on the peak values of the flow-rate as well as on the time of concentration. For the rainfalls of the short duration, moving over the catchment in the direction accordant to the general flow direction in the pipes, the peak flow-rates were greater than 100% in comparison to a flow-rates obtained for a static conditions (uniform rainfall over the whole catchment).
EN
The purpose of the paper is to analyze the spatial variability of precipitation in Poland in the years 1981–2010. The average annual rainfall was 607 mm. Precipitation in Poland is characterized by high spatial and temporal variability. The lowest annual precipitation was recorded in the central part of the country, where they equaled 500 mm. The highest annual precipitation totals were determined in the south, equaling 970 mm. The average precipitation in the summer half-year is 382 mm (63% of the annual total). On the basis of data from 53 climate stations, maps were made of the spatial distribution of precipitation for the period of the year and winter and summer half-year. The kriging method was used to map rainfall distribution in Poland. In the case study, cross-validation was used to compare the prediction performances of three periods. Kriging, with exponential type of semivariogram, gave the best performance in the statistical sense. Their application is justices especially in areas where landform is very complex. In accordance with the assumptions, the mean prediction error (ME), mean standardized prediction error (MSE), and root mean-square standardized prediction error (RMSSE) values are approximately zero, and root-mean-square prediction error (RMSE) and average standard error (ASE) reach values well below 100.
EN
Phytoplankton species are dominant components in reservoir ecosystems, yet little is known about their variability and dynamics, especially along the depth continuum. This study examined vertical and horizontal differences in phytoplankton communities in a typical subtropical deep reservoir (i.e. Dongzhen Reservoir) from 2011 to 2012. Phytoplankton communities separated into four groups based on the biomass data, indicating that temporal differences in the community structure were greater than spatial differences. Autumn communities had the highest diversity measured by the Shannon-Wiener index (2.47±0.07), while summer communities had the lowest diversity (0.46±0.09). Both winter and spring communities were dominated by diatoms (90.4±1.7%), while cyanobacteria dominated in summer communities during our sampling period. In spring and summer, however, the three surface communities characterized by high biomass were most similar to each other, indicating that vertical variation was significantly higher than horizontal differences. Furthermore, Cylindrospermopsis raciborskii accounted for over 96% of the total phytoplankton biomass in the summer surface water. The redundancy analysis (RDA) illustrated that the temporal factor (summer), the spatial factor (depth), and nutrients (nitrite and nitrate nitrogen, ammonium nitrogen, phosphate phosphorus) were significant variables affecting the dynamics of phytoplankton communities. High temperature with stable thermal stratification might have been the cause of C. raciborskii dominance in Dongzhen Reservoir in summer. Regular and long-term monitoring of dominant species is urgently needed for water quality protection and sustainable reservoir management.
EN
We developed a Faxon fir (Abies faxoniana) tree-ring width chronology at the timberline in the western Qinling Mountains, China. Herein February–July mean temperature was reconstructed for Zhouqu in the western Qinling Mountains back to AD 1650 based on the standard chronology. The climate/tree-growth model accounts for 43.5% of the instrumental temperature variance during the period 1972–2006. Spatial correlation analyses with the gridded temperature data shows that the tem-perature reconstruction captures regional climatic variations over central and southeast China, and strong teleconnections with the nearby High Asia. There is a good agreement with cold and warm pe-riods previously estimated from tree-rings in Nepal, India and southwest China. The temperature re-construction indicates that there was pronounced cooling in Zhouqu during the Maunder Minimum (late 1600s to early 1700s). The cold period (1813–1827) of the temperature reconstruction coincide with the volcanic eruptions. Significant spectral peaks are found at 56.9, 22.3, 11.4, 2.9, 2.8, 2.6, 2.2 and 2.0 years. The spatial correlation patterns between our temperature reconstruction and SSTs of the Atlantic and Pacific Oceans suggest a connection between regional temperature variations and the atmospheric circulations. It is thus revealed that the chronology has enough potential to reconstruct the climatic variability further into the past.
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