The Sweeping-out of Dust by Radiation Pressure of Stars and Chemical Composition Peculiarities of Disc Galaxies

Astronomy Reports - We consider the drift of dust grains of various sizes and chemical compositions caused by the stellar radiation pressure in the vicinity of the Milky Way. When integrating the...     

Ionic Composition of the Earth’s Exosphere during a Reversal of the Solar Magnetic Field

Doklady Earth Sciences - This paper analyzes measurement data on the ionic composition of the upper atmosphere at altitudes of 810–830 km in the period from 2009 to 2018; the measurements...     

A Possible Mechanism of Variations in the Electric Field of the Surface Atmosphere during Strong Remote Earthquakes

Doklady Earth Sciences - A mechanism for the appearance of anomalous variations in the vertical component of the electric field strength recorded at the Mikhnevo Geophysical Observatory of...     

Morphology of Crystals Growing in Impact Diamonds of the Popigai Astrobleme (Experimental Data)

Doklady Earth Sciences - Experimental results on the growth of cubic diamond on lonsdaleite-bearing diamonds from the Popigai astrobleme at 5.5 GPa and 1450°C in the Fe–Ni–C system...     

Dynamics of Dissolved Carbon in the Mainstem of the Lena River in July 2017

Doklady Earth Sciences - The dynamics of dissolved carbon forms in the waters of the mainstem of the Lena River from the middle reaches (the city of Yakutsk) to the nearshore zone of the Laptev Sea...     

Observations of Tilt Deformations in Moscow during the November 12, 2017, Earthquake at the Iran–Iraq Boundary

Doklady Earth Sciences - A residual tilt after a teleseismic earthquake is described in this work. The results of static and dynamic modeling of this event fit the measured values. The conditions...     

Results of the Study of Zircon (SIMS) from Granitoids of the Konstantinovskii Stock (Area of the Sukhoi Log Gold Deposit): Age,Sources, and Geological Consequences

Doklady Earth Sciences - The results of U–Pb geochronological (SIMS) study of zircons from granitoids of the Konstantinovskii Stock located 6 km from the Sukhoi Log gold deposit are reported....     

Metal-enriched nanoparticles and black carbon: A perspective from the Brazil railway system air pollution

Having a better understanding of air pollutants in railway systems is crucial to ensure a clean public transport. This study measured, for the first time in Brazil, nanoparticles (NPs) and black carbon (BC) on two ground-level platforms and inside trains of the Metropolitan Area of Porto Alegre (MAPA). An intense sampling campaign during thirteen consecutive months was carried out and the chemical composition of NPs was examined by advanced microscopy techniques. The results showed that highest concentrations of the pollutants occur in colder seasons and influenced by variables such as frequency of the trains and passenger densities. Also, internal and external sources of pollution at the stations were identified. The predominance of NPs enriched with metals that increase oxidative stress like Cd, Fe, Pb, Cr, Zn, Ni, V, Hg, Sn, and Ba both on the platforms and inside trains, including Fe-minerals as hematite and magnetite, represents a critical risk to the health of passengers and employees of the system. This interdisciplinary and multi-analytical study aims to provide an improved understanding of reported adverse health effects induced by railway system aerosols.     

Analysis of mobilized stress ratio of gap-graded granular materials in direct shear state considering coarse fraction effect

Weathered rockfill materials, characterized by a mixture of soil matrix and rock aggregates, are widely distributed in mountainous areas. These soils are frequently used for subgrade or riprap in engineering practice, and the mobilized shear strength is crucial for analyzing the displacement and stability of these geo-structures. A series of direct shear tests are performed on a gap-graded soil with a full range of coarse fraction. The behavior of gap-graded soils is analyzed, and a simple model is proposed for the evolution of mobilized stress ratio during direct shearing process based on mixture theory. The change of inter-aggregate configuration is incorporated by introducing a structure variable which increases with coarse fraction and decreases approximately linearly with the overall horizontal shear strain in double logarithmic plot. It reasonably reflects a gradually transformation from a matrix-sustained structure into an aggregate-sustained one with the increase of coarse fraction. The model has four parameters, and at least two direct shear tests need to be done for the calibration. Validation of the model is done by using the test data in this work and those from the literature.

     

An effective stress-based DSC model for predicting the coefficient of lateral soil pressure in unsaturated soils

Acta Geotechnica - In this study, an analytical model is developed to establish a framework for predicting the coefficient of lateral soil pressure in unsaturated soils. To this end, the disturbed...