Multi-methodological approach to evaluate trace elements and major components in wetland system with subsaline and freshwater characteristics     

Vlado Cuculić  Stanislav Frančišković-Bilinski  Halka Bilinski  Krešimir Maldini  Damir Tomas  Nenad Tomašić 《Environmental Earth Sciences》2016,75(20):1351

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Flowing Well—Time-Domain Solution and Inverse Problem Revisited     

Tomas Perina 《Ground water》2021,59(3):438-442

Time-domain analytical solution for groundwater flow to a fully penetrating flowing well is derived using the same substitution technique used to re-derive (Perina 2010) the Theis (1935) equation and the approximate solution by Mishra and Guyonnet (1992) is confirmed. The exponential integral-based flowing well function is a computationally effective alternative to the original Jacob and Lohman (1952) solution in integral form. For a constant drawdown test, the ratio of drawdown at an observation well to the flowrate is equivalent to drawdown response to pumping at unit constant rate; the transformed observations can be analyzed using the Theis (1935) function. Analysis of field test shows that simultaneous fitting to measurements of flow from the test well and drawdown at an observation well results in more accurate and better resolved estimates of aquifer properties than fitting to flow observations only.  相似文献   

Adaptive Management of the Storage Function for a Large Reservoir Using Learned Fuzzy Models     

Tomas  Kozel  Milos  Stary 《Water Resources》2021,48(4):532-543

Water Resources - A single study investigates the possibility of using adaptive control of the reservoir Vranov Reservoir situated on the Dyje River. The control algorithm uses a fuzzy model that...  相似文献   

Magnetic classification of stony meteorites: 3. Achondrites     

Pierre ROCHETTE  Jérôme GATTACCECA  Michèle BOUROT‐DENISE  Guy CONSOLMAGNO  Luigi FOLCO  Tomas KOHOUT  Lauri PESONEN  Leonardo SAGNOTTI 《Meteoritics & planetary science》2009,44(3):405-427

Abstract— A database of magnetic susceptibility measurements of stony achondrites (acapulcoite‐lodranite clan, winonaites, ureilites, angrites, aubrites, brachinites, howardite‐eucrite‐diogenite (HED) clan, and Martian meteorites, except lunar meteorites) is presented and compared to our previous work on chondrites. This database provides an exhaustive study of the amount of iron‐nickel magnetic phases (essentially metal and more rarely pyrrhotite and titanomagnetite) in these meteorites. Except for ureilites, achondrites appear much more heterogeneous than chondrites in metal content, both at the meteorite scale and at the parent body scale. We propose a model to explain the lack of or inefficient metal segregation in a low gravity context. The relationship between grain density and magnetic susceptibility is discussed. Saturation remanence appears quite weak in most metal‐bearing achondrites (HED and aubrites) compared to Martian meteorites. Ureilites are a notable exception and can carry a strong remanence, similar to most chondrites.  相似文献   

The spectrum and position of solar noise storms at decameter wavelengths     

Jérôme De La Noë  Tomas E. Gergely 《Solar physics》1977,55(1):195-209

Decametric storm radiation during the period July–August 1970 has been observed simultaneously with a high sensitivity spectrograph at Arecibo Observatory and with the log-periodic, swept-frequency array of the Clark Lake Radio Observatory. The observations complement each other; different types of fine structure emissions can be easily identified on the spectrograph records and their position can be determined from the swept-frequency recordings. We study the relative positions of the different emissions which have been observed during the storms. Four distinct sources appeared to be present. The continuum emission, the type I bursts and the flare-related type III's were all emitted at different locations. The storm type III bursts, type IIIb's and drift pairs overlapped in position, but appeared at different locations than the previously mentioned sources.On leave of absence from Instituto Argentino de Radioastronomia, Argentina.  相似文献   

Croatia in the continental traffic network of Europe     

Adolf Malić  Damir Bozičević 《GeoJournal》1996,38(4):463-468

Croatia is located on the southeastern edge of Central Europe (Ruppert 1995), between the navigable Danube River and the Adriatic Sea, so that participates not only in continental traffic, but in the maritime and river traffic of Europe as well.Although the transit position of Croatia is very favorable, transportation itself has unfortunately not been developed in accordance with these advantages. This is a result of the social-economic, especially political, development of the region in the course of its history. Unfortunately, politics also influences the selection of transit routes in this part of Europe today. With the break-up of socialist states, particularly the former Yugoslavia, new states have appeared which are seeking their place in the European traffic network. Because of the momentarily uncertain political circumstances, the construction of some transit routes in Croatia have not been foreseen in international developmental plans for continental transit, despite the fact that they would be logically expected given the advantages of their position.  相似文献   

Estimation of mean water residence times and runoff generation by0 measurements in a Pre-Alpine catchment (Rietholzbach, Eastern Switzerland)     

Tomas Vitvar  Werner Balderer 《Applied Geochemistry》1997,12(6):787-796

Stable isotopes (¹⁸0) are used to investigate hydrological processes in the small Pre-Alpine research catchment Rietholzbach in NE Switzerland. The catchment covers an area of 3.18 km² and ranges from 680 to 960 m a.s.l. The¹⁸0 concentration in rainfall and in runoff at various sites, including a lysimeter installed within the catchment, over a 2-a period are investigated. First, conceptual flow models are applied to determine the mean water residence times of different systems of the basin and their storage properties. As a second approach, the separation of runoff components using¹⁸O and Mg ions as tracer during some storm flow events was carried out. The following flow mechanisms can be identified from the modelling results: (i) lateral hillslope fluxes, which are faster in the part of the Tertiary Molasse sediments and slower in the part of the Quaternary deposits, and (ii) relatively slow vertical infiltration processes through the soil layer within the lysimeter. Mean residence times of 12.5 months result for the total catchment baseflow component and 24.5 months for the baseflow from the upper part of the catchment, respectively. For the lysimeter seepage water, a mean residence time of about 200 days was obtained. During the intensive storm events, a fast reaction of the stored subsurface water due to heavy precipitation and an expulsion of this storage water amounting to a considerable portion of the total basin runoff can be detected.  相似文献   

An efficient method for the numerical calculation of viscous effects on transient long waves     

Tomas Torsvik  Philip L.-F. Liu 《Coastal Engineering》2007

Previous studies have shown that the Boussinesq equations can be used to calculate the instantaneous bottom shear stress induced by transient or periodic waves. The bottom friction term occurs as a convolution integral in time in the continuity equation. The exact numerical integration of a convolution integral demands large computational resources, which makes the method less useful for large scale computations. In this paper we explore how the value of the convolution integral can be estimated if we only use the values of the variables in a limited number of time steps, and discuss the accuracy and computational cost of this method.  相似文献   

The Diatom Nitzschia sicula (Castr.) Hust. and Naupliar Faecal Minipellets in the Adriatic sea     

Damir  Vili&#;&#;  Frano  Kr&#;ini&#; Zlatko  Bi&#;ani&#; 《Marine Ecology》1994,15(1):27-39

Abstract. Nitzschia sicula (C astr .) H ust ., a planktonic pennate diatom, dominated the microphytoplankton (10⁴-5 times 10⁴ cells. 1^-1) in the central, oligotrophic Southern Adriatic Pit waters (20-50m layer) in May 1990. Nauplii dominated the microzooplankton (3 indiv. 1^-1in the 0-50m layer, 130 μm mean body length) and produced a considerable amount of faecal (mini)pellets (1900. 1^-1 at 50m, mean diameter 47μm), which were compactly filled with N. sicula frustules. The subsurface accumulation of diatoms and nauplii was probably the result of both productive activity under specific hydrographic conditions and the convergence in a relatively strong southern Adriatic cyclonic gyre; the advective transport of populations along the shear zone, at the boundary between water masses of different thermo-haline characteristics may also have played a role. The amount of minipellets was high if compared with the data available from other seas. This was probably due to high production of minipellets, their slow sinking rate, and/or an absence of manipulation of the faecal material by zooplankton.  相似文献   

Freshwater Phytoplankton Bloom in Visovac Lake - A Possible Cause of Benthic Mortality in Krka Estuary (Adriatic Sea, Croatia)     

Donat  Petricioli  Tatjana  Bakran-Petricioli  Damir  Vili&#;i&#; Antonieta  Po&#;ar-Domac 《Marine Ecology》1996,17(1-3):373-382

Abstract. In late summer and early autumn of 1989 benthic mortality in the upper part of Krka estuary extended from the Skradinski buk waterfalls to approximately 5 km downstream. Dead benthic organisms were found on the bottom at depths of up to 4.5 m. During August, a freshwater phytoplankton bloom was recorded in Visovac lake (which supplies the Skradinski buk waterfalls). The green tide in the lake was composed of up to 11.9 million cells. 1^--¹, predominantly of Synedra acus and Dinobtyon sertularia . At that time the maximal total inflow of phytoplankton cells through the waterfalls was approx. 0.41 S^-I (38000 1. d^-1). Cells of these two species died after reaching the salt wedge and the cummulative effect of their decomposition apparently caused an oxygen demand sufficient enough to trigger the benthic mortality. Due to the water mass dynamics, the spreading of mortality downstream was slow (from August to October, approx. 5 km). Certain benthic fishes (like Gobius sp.) were observed on the bottom of the affected area in mid-October 1989.  相似文献