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51.
D. Maričić B. Vršnak M. Dumbović T. Žic D. Roša D. Hržina S. Lulić I. Romštajn I. Bušić K. Salamon M. Temmer T. Rollett A. Veronig N. Bostanjyan A. Chilingarian B. Mailyan K. Arakelyan A. Hovhannisyan N. Mujić 《Solar physics》2014,289(1):351-368
We study heliospheric propagation and some space weather aspects of three Earth-directed interplanetary coronal mass ejections (ICMEs), successively launched from the active region AR 11158 in the period 13?–?15 February 2011. From the analysis of the ICME kinematics, morphological evolution, and in situ observations, we infer that the three ICMEs interacted on their way to Earth, arriving together at 1 AU as a single interplanetary disturbance. Detailed analysis of the in situ data reveals complex internal structure of the disturbance, where signatures of the three initially independent ICMEs could be recognized. The analysis also reveals compression and heating of the middle ICME, as well as ongoing magnetic reconnection between the leading and the middle ICME. We present evidence showing that the propagation of these two, initially slower ICMEs, was boosted by the fastest, third ICME. Finally, we employ the ground-based cosmic ray observations, to show that this complex disturbance produced a single cosmic ray event, i.e., a simple Forbush decrease (FD). The results presented provide a better understanding of the ICME interactions and reveal effects that should be taken into account in forecasting of the arrival of such compound structures. 相似文献
52.
Consequences of climate change for the soil climate in Central Europe and the central plains of the United States 总被引:2,自引:0,他引:2
Miroslav Trnka Kurt Christian Kersebaum Josef Eitzinger Michael Hayes Petr Hlavinka Mark Svoboda Martin Dubrovský Daniela Semerádová Brian Wardlow Eduard Pokorný Martin Možný Don Wilhite Zdeněk Žalud 《Climatic change》2013,120(1-2):405-418
This study aims to evaluate soil climate quantitatively under present and projected climatic conditions across Central Europe (12.1°–18.9° E and 46.8°–51.1° N) and the U.S. Central Plains (90°–104° W and 37°–49° N), with a special focus on soil temperature, hydric regime, drought risk and potential productivity (assessed as a period suitable for crop growth). The analysis was completed for the baselines (1961–1990 for Europe and 1985–2005 for the U.S.) and time horizons of 2025, 2050 and 2100 based on the outputs of three global circulation models using two levels of climate sensitivity. The results indicate that the soil climate (soil temperature and hydric soil regimes) will change dramatically in both regions, with significant consequences for soil genesis. However, the predicted changes of the pathways are very uncertain because of the range of future climate systems predicted by climate models. Nevertheless, our findings suggest that the risk of unfavourable dry years will increase, resulting in greater risk of soil erosion and lower productivity. The projected increase in the variability of dry and wet events combined with the uncertainty (particularly in the U.S.) poses a challenge for selecting the most appropriate adaptation strategies and for setting adequate policies. The results also suggest that the soil resources are likely be under increased pressure from changes in climate. 相似文献
53.
Stanko Žuljić 《GeoJournal》1996,38(4):425-429
As of 1991, in the Republic of Croatia 16 percent of the total population was made up of national minorities. A large part of this figure consists of minrity nations who are the descendants of settlers from the era of Ottoman conquest during the sixteenth and seventeenth centuries, the Austrian colonization in the eighteenth and nineteenth centuries, and partially due to inter-republic migrations during the existence of the Yugoslav state.The most numerous national minority in 1991 were the Serbs (582,000, or 12.16% of the total population). The Serbian national minority is scattered throughout the Croatian state, so that in Croatia there is no integral Serbian ethnic territory. The other national minorities in Croatia are much smaller in number (Bosnian Muslims, 43,000; Slovenes, 22,000; Hungarians, 22,000; Italians, 21,000; Czechs, 13,000; Albanians, 12,000; etc.).The conflicts provoked by Greater Serbian politics and the wartime aggression against Croatia resulted in migrations, the consequence of which is the reduction in the number of the Serbian national minority in the Republic of Croatia. 相似文献
54.
55.
A. Žgajnar Gotvajn M. Bistan T. Tišler A. J. Englande J. Zagorc-Končan 《International Journal of Environmental Science and Technology》2013,10(6):1141-1148
The aim of this research was to assess the efficiency of Fenton’s oxidation for degradation of endocrine disruptor bisphenol A (BPA) with emphasis on extent of accompanying adsorption. Adsorption on the waste sludge resulting from the Fenton’s oxidation could represent a significant impact on the final removal efficiency of BPA. Fenton’s oxidation was accomplished at two concentrations of BPA (0.228 and 22.8 mg L?1); both at the selected molar ratio of reagents Fe2+:H2O2 (1:10), as a function of reaction time. The kinetics of adsorption of BPA on waste sludge was determined for the same two concentrations of BPA at two concentrations of waste sludge (0.1 and 6.0 g L?1). In addition to changing concentrations of BPA and sludge, the adsorption process was also influenced by parameters such as temperature, pH and contact time. Adsorption isotherms were determined. Oxidation and adsorption were monitored by gas chromatography combined with mass spectrum. It has been confirmed that BPA is not completely oxidized in Fenton’s oxidation, because it is adsorbed to formed waste ferric sludge and thus necessary precautions for sludge deposition must be observed. 相似文献
56.
Jan Vilhelm Vladimír Rudajev Roman Živor Tomáš Lokajíček Zdeněk Pros 《Geophysical Prospecting》2010,58(6):1099-1110
The purpose of this paper is the comparison of P‐wave velocity and velocity anisotropy, measured at different scales under laboratory and field conditions. A shallow seismic refraction survey with shot/receiver spacing of up to 10 m was carried out on a flat outcrop of lhertzolite in the southern part of the Balmuccia massif. Oriented rock samples were also obtained from the locality. The particular advantage of the laboratory method used is the possibility of measuring velocity in any direction under controlled conditions. Laboratory tests were made on spherical peridotite samples, 50 mm in diameter, by ultrasonic velocity measurements in 132 directions (meridian and parallel networks) under confining stress ranging from atmospheric to 400 MPa. The mean P‐wave velocity of the field and laboratory data differed by between 20–30%. In addition, P‐wave velocity anisotropy of 25% was detected in the field data. Whereas the anisotropy in the laboratory samples in the same orientation as the field surveys was less than 2%. This observed scaling factor is related to the different sampling sizes and the difference in frequencies of applied elastic waves. With an ultrasonic wavelength of 10 mm, laboratory samples represent a continuum. The field velocities and velocity anisotropy reflect the presence of cracks, which the laboratory rock samples do not contain. Three sub‐vertical fracture sets with differing strikes were observed in the field outcrop. Estimates of fracture stiffness from the velocity anisotropy data are consistent with other published values. These results highlight the difficulty of using laboratory velocity estimates to interpret field data. 相似文献
57.
Mass Fractions of Forty‐Six Major and Trace Elements,Including Rare Earth Elements,in Sediment and Soil Reference Materials Used in Environmental Studies 下载免费PDF全文
Željka Fiket Nevenka Mikac Goran Kniewald 《Geostandards and Geoanalytical Research》2017,41(1):123-135
Development of new techniques, enabling simultaneous determination of large numbers of elements in environmental samples, can force analysts to use certified reference materials that do not contain all the elements of interest. In this paper, the mass fractions of forty‐six major and trace elements, including rare earth elements (REE), are presented in one soil (NCS DC 77302 also known as GBW 07410) and five sediment (Metranal‐1, IAEA 405, MESS‐3, NCS DC 73309 also known as GBW 07311 and NCS DC 75301 also known as GBW 07314) certified reference materials determined by high resolution inductively coupled plasma‐mass spectrometry. The selected certified materials represent a spectrum of geological matrices often analysed in environmental studies. Measured elements include certified elements, elements listed with information values as well as new elements absent from certificates, including REEs and some other elements. REE + Y mass fractions in the river sediment reference material Metranal‐1 are reported for the first time. The results obtained are in agreement with available certified or information values. 相似文献
58.
Stratabound epigenetic dolomite occurs in carbonate facies of the Barrandian basin (Silurian and Devonian), Czech Republic.
The most intense dolomitization is developed in bioclastic calcarenites within the transition between micritic limestone and
shaledominated Přídolí and Lochkov formations deposited on a carbonate slope. Medium-crystalline (100–400 μm), inclusion-rich,
xenotopic matrix dolomite (δ
18O=−4.64 to −3.40‰ PDB;δ
13C=+1.05 to +1.85‰ PDB) which selectively replaced most of the bioclastic precursor is volumetrically the most important dolomite
type. Coarse crystalline saddle dolomite (δ
18O=−8.04 to −5.14‰ PDB;δ
18C=+0.49 to +1.49 PDB) which precipitated in fractures and vugs within the matrix dolomite represents a later diagenetic dolomitization
event. In some vugs, saddle dolomite coprecipitated with petroleum inclusion-rich authigenic quartz crystals and minor sulfides
which, in turn, were post-dated by semisolid asphaltic bitumen. The interpretation of the dolomitization remains equivocal.
Massive xenotopic dolomite, although generally characteristic of a deeper burial setting, may have been formed by a recrystallization
of an earlier, possibly shallow burial dolomite. Deeper burial recrystallization by reactive basinal pore fluids that presumably
migrated through the more permeable upper portion of the Přídolí sequence appears as a viable explanation for this dolomitization
overprint. Saddle dolomite cement of the matrix dolomite is interpreted as the last dolomitization event that occurred during
deep burial at the depth of the oil window zone. The presence of saddle dolomite, the fluid inclusion composition of associated
quartz crystals, and vitrinite paleogeothermometry of adjacent sediments imply diagenetic burial temperatures as high as 160°C.
Although high geothermal gradients in the past or the involvement of hydrothermally influenced basinal fluids can account
for these elevated temperatures, burial heating beneath approximately 3-km-thick sedimentary overburden of presumably post-Givetian
strata, no longer preserved in the basin, appears to be the most likely interpretation. This interpretaion may imply that
the magnitude of post-Variscan erosion in the Barrandian area was substantially greater than previously thought. 相似文献
59.
Summary Kutnohorite-quartz veins penetrate through a weakly metamorphosed Late Proterozoic sedimentary rhodochrosite carbonate in pyrite shales. Kutnohorite is pleochroic ranging from colourless () to pinkish grey (), =1.735, =1,543,d=3.066g·cm–3;a
0=4.852(1),c
0=16.219(7) Å. A quantitative chemical analysis leads to the formula (Ca0.95Mn0.05)1.00(Mn0.64Mg0.23Fe0.13)1.00(CO3)2.04. An electron microprobe scanning reveals considerable microscale inhomogeneity in cleavage rhombohedrons taken from a coarsely grained aggregate. It is mostly of the character of periodic fluctuations of the main element contents around an average value. There is a strong prevalence of an Fe+Ca–Mn+Mg antagonism, the extremes of compositonal differences lying in distances of 0.0X mm. The fluctuation maxima amount to about 9% for FeO, 6% for MnO, 3% for CaO, and 1.5% for MgO. In one of the samples even a two phase character with the above antagonism between the two phases was detected by X-rays. The inhomogeneities are due, partly at least, to the Fe-metasomatic processes that followed the formation of the kutnohorite by Alpine-paragenesis hydrothermal metamorphism.
With 4 Figures 相似文献
Kutnohorit aus der Pyrit-und Manganlagerstätte von Chvaletice (Ostböhmen)
Zusammenfassung Kutnohorit-Quarzgänge durchdringen ein schwach metamorphes jungproterozoisches sedimentäres Rhodochrositkarbonat in pyritischen Schiefern. Der Pleochroismus von Kutnohorit liegt zwischen farblos () und rosagrau (), =1,735, =1,543;d=3,066 g·cm–3;a 0=4,852(1),c 0=16,219(7) Å. Die quantitative chemische Analyse des Minerals ergibt Formel (Ca0,95Mn0,05)1,00(Mn0,64Mg0,23Fe0,13)1,00(CO3)2,04. Elektronenmikrosondenuntersuchungen zeigen eine starke mikroskopische Inhomogenität in den Spaltrhomboedern von einem grobkörnigen Kutnohoritaggregat. Sie ist meistens durch periodische Schwankungen der Hauptelementgehalte um einen Mittelwert hervorgerufen. Antagonistische Beziehungen von Fe+Ca und Mn+Mg überwiegen, die extremen Werte von Elementgehalten liegen in Abständen von 0,0X mm. Die höchsten Schwankungen erreichen etwa 9% für FeO, 6% für MnO, 3% für CaO und 1,5% für MgO. In einer Probe konnten röntgenographisch sogar zwei Kutnohoritphasen mit dem erwähnten Antagonismus zwischen den Phasen bewiesen werden. Die Inhomogenitäten wurden wahrscheinlich meistens durch Fe-metasomatische Vorgänge nach der Kristallisation des Kutnohorits während der hydrothermalmetamorphen Prozesse der Alpinen Paragenese hervorgerufen.
With 4 Figures 相似文献
60.
The biogeochemical study was carried out at the Lesni potok (LP)catchment, Central Bohemia, Czech Republic. The ecosystem was impacted by heavy acid depositionduring the industrial development in 1980–1990. The catchment is forested mostly by two tree species, Norwayspruce and European beech. The Be concentration in the granite bedrock is 12.6 mg kg-1. Theplagioclase contains the highest Be concentrations out of the rock-forming minerals. Elevatedconcentration of Be (5.4 mu;g L-1) in surface waters is a result of its mobilization from the soils(3.9 mg kg-1) and weathered rock by acid precipitation. As the pH of the precipitation and consecutivelypH of the surface waters is increasing in the Czech Republic, the Be concentrations in the surface watersgradually decrease. Groundwater with high pH values contains lower concentrations of Be (0.17 g L-1)than surface waters. The soils at prone area of the catchment are depleted in Be compared to thesoils in the riparian zones. The vegetation located on the prone area contains lower concentrations of theBe than vegetation at riparian zones. The monitoring of Be in the environment is important with respectto its possible harmful effects on aquatic biota and root systems of the plants. 相似文献