scholarly journals The Effect of Differentiation Processes in Tholeiite-Basalt Melts on the Rare Elements Distribution

2021 ◽  
Vol 906 (1) ◽  
pp. 012031
Author(s):  
G. Albina Kopylova ◽  
S. Sargylana Gogoleva
Keyword(s):  
Cross Section ◽  
Large Scale ◽  
Total Concentration ◽  
Material Composition ◽  
Reference List ◽  
Rare Elements ◽  
Native Iron ◽  
Middle Paleozoic ◽  
The Cross ◽  
The Impact

Abstract Basite magmatism has been manifested repeatedly for a long time in various geodynamic structures within the eastern part of the Siberian platform. In the Middle Paleozoic, it was related to rifting processes, and in the Late Paleozoic-Early Mesozoic – to the initiation and development of trap syneclises. Differences of the geodynamic regime of magma formation are displayed in the material composition of rocks. This report presents a generalizing study of the petro-geochemical features of the tholeiitic basaltic melts formed in different geodynamic settings. The initial magmas composition changes significantly at different stages of the magmatic system development. Using multicomponent analysis, we reviewed the impact of the fractionation processes of the basal melt, which occurred under various PT conditions, on its material composition. Among the trapp bodies there are powerful differentiated intrusions. A significant change of the composition occurs during the intra-chamber differentiation of the melt in a sequence of rock strata varied from the basic magnesian to felsic alkaline rocks. In the resulting series of rocks, the content of rare elements included in the lattice of the early femic phases decreases, as well as the accumulation of almost all incompatible elements. The evolution of melts of normal alkalinity occurs with an increase of REE content and their insignificant separation. Intrusions that have undergone the stage of high-pressure fractionation in the deep transitional chamber are of particular importance. As a result of such differentiation, a peculiar group of rocks is formed in the cross section of the Middle Paleozoic bodies, such as monzonite-porphyries in one case and anorthosite gabbro-dolerites - in the other. . It is established that the monzoitoid type of differentiation is characterized by accumulation of LREE, LILE and elements of the zirconium group Nb, Ta, Hf and Y. Isolation of anorthosite gabbro-dolerites in the cross-section of bodies, as well as an increase in the content of aluminum, calcium, and strontium in them, is an indication of the anorthositic tendency of magmatic melt differentiation/When the basite-tholeiite melt interacts with the mantle reducing fluid in the deep core, its metallization occurs with the release of drop-liquid separations of native iron up to the formation of its large segregations. Intrusions with a large-scale content of native iron are found among the trap formations of Siberia. All this leads to a decrease in the total concentration and activity of iron in the partially metallized silicate matrix, there is a significant increase in the content of MgO and trace elements-Ni, Co, Cr. The Fe-phase-containing intrusives are characterized by minimal LILE, HFSE, and REE contents. Start your abstract here… 250 to 500 words concise and factual abstract is required. The abstract should include the purpose of research, principal results and major conclusions. References should be avoided, if it is essential, only cite the author(s) and year(s) without giving reference list. Prepare your abstract in this file and upload it into the registration web field.

scholarly journals Mineralogy and geochemistry of native iron

2021 ◽  
Vol 906 (1) ◽  
pp. 012032
Author(s):  
G. Kopylova Albina
Keyword(s):  
Cross Section ◽  
Large Scale ◽  
System Development ◽  
Total Concentration ◽  
Material Composition ◽  
Reference List ◽  
Native Iron ◽  
Middle Paleozoic ◽  
The Cross ◽  
The Impact

Abstract Basite magmatism has been manifested repeatedly for a long time in various geodynamic structures within the eastern part of the Siberian platform. In the Middle Paleozoic, it was related to rifting processes, and in the Late Paleozoic-Early Mesozoic – to the initiation and development of trap syneclises. Differences of the geodynamic regime of magma formation are displayed in the material composition of rocks. This report presents a generalizing study of the petro-geochemical features of the tholeiitic basaltic melts formed in different geodynamic settings. The initial magmas composition changes significantly at different stages of the magmatic system development. Using multicomponent analysis, we reviewed the impact of the fractionation processes of the basal melt, which occurred under various PT conditions, on its material composition. Among the trapp bodies there are powerful differentiated intrusions. A significant change of the composition occurs during the intra-chamber differentiation of the melt in a sequence of rock strata varied from the basic magnesian to felsic alkaline rocks. In the resulting series of rocks, the content of rare elements included in the lattice of the early femic phases decreases, as well as the accumulation of almost all incompatible elements. The evolution of melts of normal alkalinity occurs with an increase of REE content and their insignificant separation. Intrusions that have undergone the stage of high-pressure fractionation in the deep transitional chamber are of particular importance. As a result of such differentiation, a peculiar group of rocks is formed in the cross section of the Middle Paleozoic bodies, such as monzonite-porphyries in one case and anorthosite gabbro-dolerites - in the other. It is established that the monzoitoid type of differentiation is characterized by accumulation of LREE, LILE and elements of the zirconium group Nb, Ta, Hf and Y. Isolation of anorthosite gabbro-dolerites in the cross-section of bodies, as well as an increase in the content of aluminum, calcium, and strontium in them, is an indication of the anorthositic tendency of magmatic melt differentiation/When the basite-tholeiite melt interacts with the mantle reducing fluid in the deep core, its metallization occurs with the release of drop-liquid separations of native iron up to the formation of its large segregations. Intrusions with a large-scale content of native iron are found among the trap formations of Siberia. All this leads to a decrease in the total concentration and activity of iron in the partially metallized silicate matrix, there is a significant increase in the content of MgO and trace elements-Ni, Co, Cr. The Fe-phase-containing intrusives are characterized by minimal LILE, HFSE, and REE contents. Start your abstract here… 250 to 500 words concise and factual abstract is required. The abstract should include the purpose of research, principal results and major conclusions. References should be avoided, if it is essential, only cite the author(s) and year(s) without giving reference list. Prepare your abstract in this file and upload it into the registration web field.

scholarly journals Experimental and Numerical Study on Ultimate Shear Load Carrying Capacity of Corroded RC Beams

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Zhanzhan Tang ◽  
Zhixiang He ◽  
Zheng Chen ◽  
Lingkun Chen ◽  
Hanyang Xue ◽  
...  
Keyword(s):  
Shear Strength ◽  
Bearing Capacity ◽  
Cross Section ◽  
Loss Rate ◽  
Numerical Study ◽  
Rc Beams ◽  
Load Carrying ◽  
Shear Bearing Capacity ◽  
The Cross ◽  
The Impact

For an RC beam, the strength of steel rebar, the bonding strength between the concrete and reinforcement, and the bite action between the aggregates will deteriorate significantly due to corrosion. In the present study, 10 RC beams were designed to study the impact of corrosion on the shear bearing capacity. The mechanism of corrosion for stirrups and longitudinal bars and their effects were analyzed. Based on the existing experimental data, the correlation between the stirrup corrosion factor and the cross section loss rate was obtained. An effective prediction formula on the shear bearing capacity of the corroded RC beams was proposed and validated by the experimental results. Moreover, a numerical analysis approach based on the FE technique was proposed for the prediction of the shear strength. The results show that corrosion of the reinforcements could reduce the shear strength of the RC beams. The corrosion of stirrups can be numerically simulated by the reduction of the cross section. The formulae in the literature are conservative and the predictions are very dispersed, while the predictions by the proposed formula agree very well with the experiment results.

scholarly journals TACHYON DYNAMICS OF THE BLACK DISC LIMIT IN THE HARD SMALL x PROCESSES IN QCD

2006 ◽  
Vol 21 (07) ◽  
pp. 549-558 ◽  
Author(s):  
B. BLOK ◽  
L. FRANKFURT
Keyword(s):  
Cross Section ◽  
Impact Parameter ◽  
High Energy ◽  
Black Disk ◽  
Black Disc ◽  
Energy Behavior ◽  
Small X ◽  
The Cross ◽  
The Impact ◽  
Black Disc Limit

We investigate the effective field theory (EFT) which gives the approximate description of the scattering of two hard small dipoles in the small x processes in QCD near the black disc limit (BDL). We argue that the perturbative QCD approaches predict the existence of tachyon and visualize it in the approximation where α′P=0. We demonstrate that the high energy behavior of the cross-section depends strongly on the diffusion law in the impact parameter plane. On the other hand, almost threshold behavior of the cross section of the hard processes and multiplicities, i.e. fast increase of cross sections (color inflation), melting of ladders into color network and softening of the longitudinal distributions of hadrons are qualitatively insensitive to the value of diffusion in the impact parameter space. We evaluate α′P near the black disk limit and find significant α′P as the consequence of the probability conservation.

scholarly journals Impact of the cross section library on 93mNb activity in VVER-1000 reactor dosimetry

2020 ◽  
Vol 225 ◽  
pp. 03009
Author(s):  
P. Haroková ◽  
M. Lovecký
Keyword(s):  
Cross Section ◽  
Neutron Transport ◽  
Nuclear Data ◽  
Nuclear Data Library ◽  
The Cross ◽  
Materials Used ◽  
The Impact ◽  
Data Library ◽  
Reactor Dosimetry

One of the objectives of reactor dosimetry is determination of activity of irradiated dosimeters, which are placed on reactor pressure vessel surface, and calculation of neutron flux in their position. The uncertainty of calculation depends mainly on the choice of nuclear data library, especially cross section used for neutron transport and cross section used as the response function for neutron activation. Nowadays, number of libraries already exists and can be still used in some applications. In addition, new nuclear data library was recently released. In this paper, we have investigated the impact of the cross section libraries on activity of niobium, one of the popular materials used as neutron fluence monitor. For this purpose, a MCNP6 model of VVER-1000 was made and we have compared the results between 14 commonly used cross section libraries. A possibility of using IRDFF library in activation calculations was also considered. The results show good agreement between the new libraries, with the exception of the most recent ENDF/B-VIII.0, which should be further validated.

Financial Constraints, Monetary Policy Shocks, and the Cross-Section of Equity Returns

2019 ◽  
Vol 33 (9) ◽  
pp. 4367-4402 ◽  
Author(s):  
Sudheer Chava ◽  
Alex Hsu
Keyword(s):  
Monetary Policy ◽  
Cross Section ◽  
Equity Returns ◽  
Monetary Policy Shocks ◽  
Federal Funds ◽  
Federal Funds Rate ◽  
Oxford University ◽  
Policy Shocks ◽  
The Cross ◽  
The Impact

Abstract We analyze the impact ofa unanticipated monetary policy changes on the cross-section of U.S. equity returns. Financially constrained firms earn a significantly lower (higher) return following surprise interest rate increases (decreases) as compared to unconstrained firms. This differential return response between constrained and unconstrained firms appears after a delay of 3 to 4 days. Further, unanticipated Federal funds rate increases are associated with a larger decrease in expected cash flow news, but not discount rate news, for constrained firms relative to unconstrained firms. Authors have furnished an Internet Appendix, which is available on the Oxford University Press Web site next to the link to the final published paper online.

City Occupancy and Road Capacity Model

2014 ◽  
Vol 1044-1045 ◽  
pp. 1538-1540 ◽  
Author(s):  
Yi Lin Fan ◽  
Bei Chen Cheng ◽  
Li Li Cao ◽  
Kun Cheng Huang
Keyword(s):  
Cross Section ◽  
Road Traffic ◽  
The Road ◽  
Road Capacity ◽  
Traffic Capacity ◽  
Capacity Model ◽  
The Cross ◽  
Definition Of ◽  
The Impact ◽  
Accident Case

In this paper, we study the impact of city driveway occupancy on the urban road traffic capacity. Through the analysis of the scene of an accident case, we gained the vehicle statistics within a cross section in unit time and then did calculation and simulation. The work is concluded as a reasonable model of vehicle queue relationship evaluation.First, on the base of the definition of traffic capacity, statistics of the cars in the cross section before the accident, during the accident and after the accident have been respectively acquired in unit time (1 min). Then we employ Matlab to do the interpolation fitting, drawing the change of actual capacity of the road from the beginning time of an accident to the time when traffic resumes. The work comes to a conclusion that the change of the capacity at the cross section has a pattern of periodic fluctuation.

Effects of Cross-Section Ovalization of Subsea Thin-Walled Bends Under In-Plane Bending

2010 ◽  
Author(s):  
Ranil Banneyake ◽  
Ayman Eltaher ◽  
Paul Jukes
Keyword(s):  
Cross Section ◽  
Computational Cost ◽  
Straight Pipe ◽  
Limit States ◽  
Element Analysis ◽  
High Tendency ◽  
Thin Walled ◽  
Plane Bending ◽  
The Cross ◽  
The Impact

Ovalization of the cross-section of bends under in-plane bending (a.k.a. Brazier effect) is a known phenomenon caused by the longitudinal stress acting on the cross-section as the pipe bends. Besides its tendency to induce stresses in the bend above what is predicted using simple beam theory, excessive cross-section ovalization is particularly critical to subsea pipes, as it can lead to collapse of the pipe under external pressure. Also, being in a plastic regime may cause the bend material to ratchet and undergo excessive strains under cyclic operational loads, especially under high-pressure high-temperature (HPHT) conditions. Ovalization normally results in local increase of stresses and could lead to failure of the bend before the bend globally reaches its limiting capacity. The offshore industry standards and design codes address the impact of initial ovality in straight pipes, but their applicability to bends is not clear. Therefore, this paper presents an investigation into the increased tendency of thin-walled bends to ovalize, and the effect of bend cross-section ovalization on their stiffness and yielding and collapse limit states, with emphasis on offshore applications. Due to the lack of analytical solutions for the bend response taking into account cross-section ovalization, finite element analysis (FEA) is used in this study. Predictions of the bend models are compared with those of straight pipe models and predictions of models of the bend made of beam elements (with pipe section) are compared with those of models made of brick /shell elements. The increased tendency of thin-walled bends to ovalize compared to straight pipes is investigated (e.g. 100 times in the linear range), and the impact and significance of ovalization in bends are assessed (e.g., stress increase of the order of 35% has been observed in some example situations). Also discussed in the paper is the selection of proper element specifications in order to accurately capture the ovalization response while keeping the computational cost manageable. Recommendations as to how to account for ovalization effects are presented. This paper helps to gain a better understanding of the response of subsea thin-walled bends under in-plane bending and their comparatively high tendency to ovalize compared to straight pipe, and emphasizes the significance of local effects such as cross-section ovalization, the overlooking of which may result in a significant underestimation of involved stresses and strains.

Large-scale fatigue tests on prestressed concrete beams

2021 ◽  
Author(s):  
Dennis Birkner ◽  
Steffen Marx
Keyword(s):  
Numerical Analysis ◽  
Cross Section ◽  
Prestressed Concrete ◽  
Large Scale ◽  
Concrete Beams ◽  
Fatigue Loading ◽  
Fatigue Tests ◽  
Beam Specimen ◽  
The Cross ◽  
Number Of Cycles

<p>For a better estimation of the fatigue lifetime of real structures, tests on large-scale beam specimens are more suitable than on common cylindrical specimens, since effects like local stiffness changes and stress redistributions can be reproduced more realistically. This article presents an experimental setup for large-scale concrete beams subjected to fatigue loading. Additionally, the fatigue tests are simulated with a numerical model. The results of the numerical analysis show a successively increasing damage propagating from the edge into the inner part of the cross-section in the mid span with increasing number of cycles. This results in stress redistributions which extend the lifetime of the structure. The evaluation of the experimental investigation on the first beam specimen shows a larger stiffness degradation at the upper edge than in the centre of the cross-section as well as increasing strains at this location. This matches the expected effects from the numerical analysis.</p>

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