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501.
Karst aquifers represent one of the main sources of water supply in Serbia. Wide distributions of karstic areas, abundant
reserves, and excellent quality of karst groundwater have been the reasons for its extensive use in water supply systems throughout
the country. In Serbia, 70 karstic sources have been tapped for centralized water supply, with the assessed minimal capacity
exceeding 4.5 m3/s. Most of the large cities of Eastern and Western Serbia currently use karst groundwater for water supply; however, due
to unstable flow regime when only natural springflow is tapped, numerous problems arise during the recession period (summer–autumn).
During the last two decades, after favorable conditions had been confirmed through hydrogeological survey and feasibility
studies, several newly constructed systems for artificial control of karst aquifers (mostly in Eastern Serbia) resulted in
significantly improved water supply. 相似文献
502.
Summary In connection with a number of recent publications on anomalous (excessive) absorption of shortwave radiation (SWR) by clouds, the data of aircraft observations of spectral and total SWR vertical profiles in the troposphere obtained within the CAENEX, GAAREX and FGGE programmes have been discussed. These data demonstrated persuasively the existence of substantial SWR absorption by clouds in the visible wavelength region. In this context, the results of simulation numerical medelling of the SWR transfer in clouds have been considered. These show a significant enhancement of the SWR absorption by clouds due to an increase of the mean free path of photons under an impact of multiple scattering in clouds. Another important consideration may be the impact of SWR-absorbing pollutants in clouds, especially soot aerosols.With 4 Figures 相似文献
503.
Summary Koshava is a gusty wind of moderate to strong intensity, blowing from the south-eastern direction, over the area of the Republic of Serbia. It is caused by the interaction between the synoptic circulation and the orography of the Carpathian and the Balkan mountains. The Koshava wind can damage buildings, factories and industrial plants or city infrastructure. Therefore it is important to estimate its gust and the gustiness factor on the basis of the measured data.This paper discusses a statistical analysis of wind data in the maximum influence area of the Koshava wind in the periods of maximum duration of Koshava. The focus of the paper is the examination of urban and suburban effects on Koshava wind and the correlation between the instantaneous maximum wind speed and the hourly mean wind speed. The best fitting with various empirical distributions is proposed.With 10 Figures 相似文献
504.
In the Central Dinarides and South Tisia different Paleozoic complexes occur in four geotectonic zones: (1) comparatively autochthonous units located in the cores of disrupted anticlines of the External Dinarides; (2) allochthonous disrupted units accompanied by more predominant Triassic formations in the Sava Nappe, which is thrust onto the northeastern margin of the External Dinarides; (3) allochthonous disrupted units, also together with Triassic formations, in the Pannonian and Durmitor nappes of the Internal Dinarides; and (4) polymetamorphic sequences in basement of the Pannonian Basin and South Tisia, respectively. This paper presents basic geological features for the main Paleozoic areas included in these four zones. The tectonostratigraphic units of the first two zones were related to the Gondwana passive continental margin, those of the third zone to the Paleotethyan oceanic realm, and those of Tisia to the active Laurussia margin. Geodynamic evolution of all these Paleozoic complexes was related to opening and closure of the Rheic and Paleotethys Oceans. Rifting processes along North Gondwana started in the Silurian, locally in the Cambrian-Ordovician, and were followed by the Late Silurian/Devonian opening of the Paleotethys. Subduction processes were active by the end of the Devonian and at the beginning of the Carboniferous along the Laurussia margin. They were followed during the Westphalian by main Variscan deformation during collision of Gondwana and Laurussia. Associated metamorphism was very low-grade in the Paleozoic units of the Sava Nappe, low-grade to epidote-amphibolite grade within the Paleozoic complexes of the Pannonian and Durmitor nappes in the Internal Dinarides, and poly-metamorphic with migmatites and granitoids in South Tisia. These processes gave rise to a Pangea stage with the Variscan basement disconformably overlain by Late Carboniferous and Permian sediments. 相似文献
505.
Dr. Vesna Marchig Dr. Heinrich Gundlach Dr. Christian Schnier 《International Journal of Earth Sciences》1979,68(3):1037-1054
Zusammenfassung Aus dem Manganknollen-reichen zentralpazifischen Radiolarienschlamm wurden 114 Sedimentproben in einzelne Fraktionen getrennt, und die Fraktionen einzeln chemisch analysiert.Die Fraktion <63 m ist aus autochthonen und terrigenen Anteilen zusammengesetzt, wobei der autochthone Anteil angereichert und der terrigene verarmt ist im Vergleich zu den durchschnittlichen Tiefseetonen. Im autochthonen Anteil sind die Elemente angereichert, die für das Wachstum von Manganknollen wichtig sind.Der nichtmagnetische Anteil aus der Fraktion >63 m besteht überwiegend aus Radiolarienschalen. Daneben ist (organogener) Apatit angereichert, und eine Phase, die wir für ein neugebildetes Tonmineral halten.Einige Komponenten ändern ihren Gehalt mit der Teufe, was auf eine diagenetische Mobilisierung schließen läßt. Es wurde errechnet, daß das Angebot an Manganknollenbildenden Metallen aus der diagenetischen Mobilisierung bei weitem den Bedarf an diesen Metallen für das Manganknollen-Wachstum übersteigt.
Chemical analyses were done on the various fractions made from 114 sediment samples collected from the radiolarian ooze in an area of the Central Pacific rich in manganese nodules.The fraction <63 n contains both terrigenous and autochtonous portions; the percentage of the autochtonaus portion is greater than in the average deep-sea clay, that of terrigenous is less. The concentration of elements important for the growth of manganese nodules is elevated in the autochtonous portion.The non-magnetic part of the fraction >63 m is composed mainly of radiolarian tests. In addition, there is en elevated organogenic apatite content and a phase that we believe to be a recently formed clay mineral.The concentration of some components varies with depth, which could be due to diagenetic mobilisation. It was calculated that the supply of diagenetically mobilized metals greatly exceeds that required for the growth of manganese nodules.
Résumé 114 échantillons de boue à radiolaires de l'Océan Pacifique central, riche en nodules de manganèse, ont été séparés en fractions, et chacune de celles-ci ont été analysées chimiquement.La fraction <63 m se compose de particules autochtones et terrigènes avec un enrichissement de la partie autochtone et un appauvrissement de la partie terrigène par rapport à la composition moyenne des argiles de grande profondeur. La partie autochtone est enrichie en éléments qui jouent un rÔle important dans la croissance des nodules de manganèse.La partie non magnétique de la fraction >63 m est composée pour sa plus grande partie de tests de radiolaires. On observe également un enrichissement d'apatite (organogène) et une phase que nous considérons comme une argile de néoformation.La teneur en certains éléments varie avec la profondeur, ce qui indique une mobilisation diagénétique. Nous avons pu calculer que le disponible en métaux entrant dans la formation des nodules de manganèse par suite de la mobilisation diagénétique dépasse de loin la quantité nécessaire á la croissance des nodules.
114 . <63 m , , . , . <64 . . . , . , . , , , .相似文献
506.
The usefulness of parallel micropetrographic and chemical investigations to illustrate the nature of kerogen is demonstrated from data obtained in the study of the Aleksinac shale (Yugoslavia). To obtain more information about the chemical nature of kerogen, the stepwise oxidation with alkaline permanganate reported earlier has been modified and supplemented with micropetrographic and chemical investigations of partially degraded kerogen concentrates isolated from each degradation step. Five different types of particles were observed in kerogen concentrates. The results both of micropetrographic and of chemical investigations indicate a heterogeneity of the Aleksinac shale kerogen and a different reactivity of the particles observed. 相似文献
507.
SummaryRock Mass Mechanical Characteristics in an Opencut at Bor Copper Mine Preliminary testing for the design of the new opencut, which will go to a depth of about 300 m, included testing rock mechanical characteristics. The character of the preliminary testing demanded by an engineering undertaking of this scale and the fundamental structural and physical properties of rock masses (fissuring, anisotropy, heterogeneity, natural stresses) are discussed and it is emphatically concluded that priority should go to in situ testing. Results are presented of determinations of the velocity of propagation of longitudinal elastic waves, elasticity modulus, coefficient of damage and shear strength parameters.With 7 Figures 相似文献
508.
Flysch sequences develop normally from pelagic sediments, over a pre-flysch transitional unit, or from a well-developed transgressive base. A different situation has been observed in the western portion of the Upper Eocene flysch basin of Ov?e Pole, Macedonia, where deep-water turbidites appear almost directly over the eroded basement, transgressively overlapping the preexisting submarine relief. These relationships are explained as results of successive phases of subsidence in the basin. The outcrop area, situated between Titov Veles and Gradsko, represented a surface without deposition in the early depositional stages. Later subsidence introduced a turbiditic deposition into the domain without a break in sedimentation. Such cases may occur also in other flysch basins where lateral migration of the main depositional trough took place during the sedimentation. 相似文献
509.
ABSTRACTMonthly water balance models (MWBMs) are often used for making flow projections under climate change. As such, these models should provide accurate flow simulations; however, they are seldom evaluated in this regard. This paper presents a comprehensive framework intended for the evaluation of the applicability of MWBMs under changing climatic conditions. The framework consists of analyses of consistency in model performance, parameter estimates and simulated water balance components, and a subjective assessment of model transferability. Four MWBMs – abcd, Budyko, GR2M and WASMOD – are used to simulate runoff in the Wimmera catchment affected by the Millennium drought. Although abcd and Budyko slightly outperformed GR2M and WASMOD, none of the models performed well in transfer to the driest period. The greatest variability is detected in simulated groundwater storage and baseflow; thus, these model components should be improved and/or enhanced calibration strategies should be employed to advance the transferability of MWBMs under changing climate. 相似文献
510.