共查询到20条相似文献，搜索用时 31 毫秒
1.
Thermal conductivity is an important parameter to consider when designing clay-based barriers for use in deep geological repositories (DGR). In the DGR environment, the infiltration of local saline groundwater can potentially change the pore fluid chemistry of a barrier over its lifetime. This change in chemistry is known to alter the thermal properties of the barrier materials. In order to examine the impact of pore fluid salinity on thermal conductivity, experiments were conducted under both distilled water and saline pore fluid conditions. The material mixtures were prepared at two different dry densities using two different salt types. Furthermore, five different thermal conductivity prediction models were selected and evaluated on their performance with respect to the experimental outcomes. In general, these results indicated that an increase in the constituent pore fluid’s salt concentration leads to a decrease in the thermal conductivity of the material. Additionally, the thermal conductivity values of the materials prepared at a high dry density were greater than of those compacted at a low dry density. 相似文献
2.
A. K. Mishra B. Kumar S. Vadlamudi 《International Journal of Environmental Science and Technology》2017,14(8):1625-1634
Owing to its low hydraulic conductivity, soil and bentonite mixture is applied as a liner material. However, the experimental determination of hydraulic conductivity, which is controlled by various physical, chemical and mineralogical factors, requires an expensive and time-consuming setup. In the present work, multigene symbolic, genetic programming was used to model functional relationships for hydraulic conductivity. The developed model was able to generalize highly nonlinear variations in data as well as predict system behavior from experimental observations. It was found that the predictions obtained from developed model agree well with experimental observations. 相似文献
3.
In this study, an investigation was performed to determine if lime-stabilized sand–bentonite mixtures are appropriate for the construction of sanitary landfills liners. For this aim, the hydraulic conductivity tests were conducted in the laboratory on sand–bentonite mixtures and lime-stabilized sand–bentonite mixtures to evaluate the effect of wetting–drying cycles. The hydraulic conductivity tests were performed to see if their hydraulic conductivities are affected by wetting–drying cycles. First series of specimens have been prepared as a mixture of sand and bentonite only. In the first series of specimens, sand was mixed with bentonite in proportions of 20, 30, 40, and 50 %. In the second series of the specimens, lime in proportions of 1, 2 and 3 % by weight was added to the mixtures of sand–bentonite in proportions of 20, 30, 40, and 50 %. From the results of the tests, it was observed that while optimum water content increased, maximum dry density decreased with addition of lime to the sand–bentonite mixtures. Generally, the hydraulic conductivity increased with the addition of lime to the mixtures but at low percentages of lime (1–2 %), however, slight decreases in k were recorded. It was also observed that the wetting–drying cycles on the permeability test indicate cure effect on specimens with addition of lime which resulted in decreased the hydraulic conductivity. 相似文献
4.
The hydraulic conductivity represents an important indicator parameter in the generation and redistribution of excess pore pressure of sand–silt mixture soil deposits during earthquakes. This paper aims to determine the relationship between the undrained shear strength (liquefaction resistance) and the saturated hydraulic conductivity of the sand–silt mixtures and how much they are affected by the percentage of low plastic fines (finer than 0.074 mm) and void ratio of the soil. The results of flexible wall permeameter and undrained monotonic triaxial tests carried out on samples reconstituted from Chlef river sand with 0, 10, 20, 30, 40, and 50 % non-plastic silt at an effective confining pressure of 100 kPa and two initial relative densities (D r = 20, 91 %) are presented and discussed. It was found that the undrained shear strength (liquefaction resistance) can be correlated to the fines content, intergranular void ratio and saturated hydraulic conductivity. The results obtained from this study reveal that the saturated hydraulic conductivity (k sat) of the sand mixed with 50 % low plastic fines can be, in average, four orders of magnitude smaller than that of the clean sand. The results show also that the global void ratio could not be used as a pertinent parameter to explain the undrained shear strength and saturated hydraulic conductivity response of the sand–silt mixtures. 相似文献
5.
Doklady Earth Sciences - Numerical modeling of the dynamics of the block structure and the resulting seismicity of the Altai–Sayan–Baikal region has been carried out. The earthquake... 相似文献
6.
Forty-one water samples in each season(both pre-and post-monsoon) were collected from different for-mations of the Kadiri schist belt located in the Anantapur district,Andhra Pradesh.The specific electrical conductiv-ity(EC) of these water samples was measured at 25℃ by using specific conductivity bridge.The specific conductiv-ity values of the water samples were also calculated by multiplying ionic concentrations with conductivity factor.It is found that the observed EC values of all water samples collected in both the seasons are different from the esti-mated EC values because of the electro-chemical properties of ions in water. 相似文献
7.
Acta Geotechnica - Compacted Gaomiaozi bentonite–sand mixtures are regarded as attractive buffer/backfill materials for nuclear waste deep geological disposal. When the mixture blocks are... 相似文献
8.
Yukai Zhuang Xiaowan Su Nilesh P.Salke Zhongxun Cui Qingyang Hu Dongzhou Zhang Jin Liu 《地学前缘(英文版)》2021,12(2)
Although nitrogen in the Earth’s interior has attracted significant attention recently,it remains the most enigmatic of the light elements in the Earth’s core.In this work,synchrotron X-ray diffraction(XRD)and electrical conductivity experiments were conducted on iron nitrides(Fe2N and Fe4N)in diamond anvil cells(DACs)up to about 70 GPa at ambient temperature.These results show that iron nitrides are stable up to at least 70 GPa.From the equation of state(EOS)parameters,iron nitrides are more compressible than iron carbides.Moreover,using the van der Pauw method and Wiedemann-Franz law,the electrical and thermal conductivity of samples were determined to be much lower than that of iron carbides.The conductivities of Fe2N and Fe4N were similar at 20–70 GPa,suggesting no evident effects by varying the N stoichiometries in iron nitrides.Iron nitrides are less dense and conductive but more compressible than carbides at 0–70 GPa.This study indicates that less nitrogen than carbon can explain geophysical phenomena in the deep Earth,such as the density deficit. 相似文献
9.
Doklady Earth Sciences - New data on the minerals of the Fe–Ni–Co–Cu–S system in the differentiated intrusions of the Southern Urals are presented. Based on a detailed study... 相似文献
10.
11.
12.
S. D. Velikoslavinskii A. B. Kotov E. B. Sal’nikova A. B. Kuznetsov V. P. Kovach N. V. Popov E. V. Tolmacheva I. V. Anisimova Yu. V. Plotkina 《Doklady Earth Sciences》2018,482(2):1265-1269
New U–Pb zircon (TIMS) results allow dating of protoliths of tonalite–trondhjemite orthogneisses of the Olekma Complex in the central part of the Chara–Olekma Geoblock (Aldan Shield) to 2825 ± 3 Ma and 2994 ± 3 Ma. Together with the results of previous geochronological studies, this proves that the Olekma Complex comprises heterochronous igneous rocks intensively reworked under amphibolite facies conditions and formed during different stages of geological evolution of the Aldan Shield. 相似文献
13.
In order to examine the precursory seismic quiescence of upcoming hazardous earthquakes, the seismicity data available in the vicinity of the Thailand–Laos–Myanmar borders was analyzed using the Region–Time–Length (RTL) algorithm based statistical technique. The utilized earthquake data were obtained from the International Seismological Centre. Thereafter, the homogeneity and completeness of the catalogue were improved. After performing iterative tests with different values of the \(r_{0}\) and \(t_{0}\) parameters, those of \(r_{0}\) = 120 km and \(t_{0}\) = 2 yr yielded reasonable estimates of the anomalous RTL scores, in both temporal variation and spatial distribution, of a few years prior to five out of eight strong-to-major recognized earthquakes. Statistical evaluation of both the correlation coefficient and stochastic process for the RTL were checked and revealed that the RTL score obtained here excluded artificial or random phenomena. Therefore, the prospective earthquake sources mentioned here should be recognized and effective mitigation plans should be provided. 相似文献
14.
Koroteev V. A. Chervyakovskiy V. S. Zaitseva M. V. Volchek E. N. Necheukhin V. M. 《Doklady Earth Sciences》2019,487(1):756-760
Doklady Earth Sciences - This paper reports on the first U–Pb dating of zircons from dacites of the volcanic paleo-edifice of the andesite–dacite complex of the Eastern Zone of the... 相似文献
15.
A. S. Ivleva V. N. Podkovyrov V. B. Ershova O. A. Anfinson A. K. Khudoley P. V. Fedorov A. V. Maslov D. Yu. Zdobin 《Doklady Earth Sciences》2016,468(2):593-597
Here we present the results of U–Pb LA–ICP–MS dating of detrital zircons from the Ediacaran–Early Cambrian deposits of the eastern part of the Baltic monoclise (Leningrad Region). The obtained age spectra of the detrital zircons suggest that, in the Ediacaran–Early Cambrian, the main clastic material source to the northwest of the Russian Platform was the Baltic Shield. Then in the Early Cambrian along with the Baltic Shield provenance, a clastic source from the Timanian margin of Baltica (northeast in modern coordinates) contributed to the deposits. The obtained data either somewhat set limits of the Timanian orogen formation as older than the previously suggested Middle Cambrian (about 510 Ma), based on the “absence of a Proto–Uralian–Timanian provenance signal” in the Sablino Formation rocks in the south Ladoga, or suggest another rearrangement of detritus transportation paths at the end of Stage 3 (Atdabanian). 相似文献
16.
The first results on current movements are presented for the western part of the Dzhugdzhur–Stanovoi Terrane based on GPS geodesy of a geodynamic survey area of the Upper Amur region. Processing of the GPS data resulted in a vector field of the displacement rates of points of the geodynamic survey area with zones of intense deformations. It was concluded from a comprehensive analysis of geological–geophysical data and estimates of the displacement rates that the terrane is characterized by kinematic integrity and was subjected to a complex of tectonic factors related to the evolution of the eastern segment of Baikal Rift Zone in the area of transpression interaction of the Eurasian and Amur plates. 相似文献
17.
Ivanov K. S. Berzin S. V. Erokhin Yu. V. Ronkin Yu. L. Khiller V. V. 《Doklady Earth Sciences》2019,484(1):97-100
Doklady Earth Sciences - Dolerites of the parallel dikes formed in a back-arc spreading setting have been dated by Sm–Nd to the Silurian (426 ± 34 Ma) for Mount Azov in the Central... 相似文献
18.
Doklady Earth Sciences - In the Precambrian sequence, namely, in the Proterozoic, Archean calcium and ferruginous carbonate rocks changed to magnesian carbonate ones. This correlates with the... 相似文献
19.
The reflectance of sediments (gray level) were measured on 11 sediment cores from the Norwegian–Greenland–Iceland Sea (Nordic
seas). The analyzed time interval covers the past five glacial–interglacial cycles. Although the results demonstrate that
the gray-level method has a potential for stratigraphic purposes, it is indicated that gray-level changes in the Nordic seas
are not necessarily driven by variations in the content of biogenic calcite. A detailed comparison of gray-level values with
contents of total CaCO3 (carbonate) and total organic carbon (TOC) reveals no overall causal link between these proxies. However, specific glacial
core sections with layers containing organic-rich sediment clasts as a consequence of iceberg-rafting seem to correlate well
with law gray-level values. Of those cores which show relatively high and comparable carbonate values in the last three main
interglacial intervals (stages 11, 5.5, and 1), stage 11 is always marked by the highest gray-level values. A close inspection
of the surface structure of the foraminiferal tests as well as the conduction of reflectance measurements on these tests leads
to the conclusion that enhanced carbonate corrosion occurred during stage 11. The test corrosion not only affected the reflectance
of the tests by making them appear whiter, it also seems responsible for the comparatively high gray-level values of the total
sediment in stage 11. In contrast, the relatively low gray-level values found in stages 5.5, and 1 are not associated with
enhanced test corrosion. This observation implies that variable degrees of carbonate corrosion can have a profound effect
on total sediment reflectance.
Received: 6 September 1998 / Accepted: 4 April 1999 相似文献
20.
The carbonate sediments from the Vendian–Cambrian shelf of the Tuva-Mongolian microcontinent were dated by Sr and C isotope chemostratigraphy. Analysis of the Sr-isotopic characteristics (0.70725–0.70873) and δ13C variations (+ 10.5 to –3.5‰), as well as their comparison with the data on the key sections of Siberia, Africa, Central Asia, Australia, South America, and Spitsbergen, showed that the carbonate sedimentary cover of the Tuva-Mongolian microcontinent accumulated at 600–520 Ma and the carbonate sediments of the Muren Formation and the basal beds of the Bokson Group near the Ukha-Gol River are the oldest. Their sedimentation followed the Marinoan global glaciation. 相似文献