Results 81 to 90 of about 279,186 (291)

Anomalous negative excursion of carbon isotope in organic carbon after the last Paleoproterozoic glaciation in North America [PDF]

open access: yes, 2010
Early Paleoproterozoic time (2.5–2.0 Ga) spanned a critical phase in Earth's history, characterized by repeated glaciations and an increase in atmospheric oxygen (the Great Oxidation Event (GOE)).
Bekker   +41 more
core   +1 more source

Organoclay interaction response to sedimentary environment and sources in Paleogene shales from the Nanpu Sag: Insights for organic matter accumulation mechanism

open access: yesThe Depositional Record, EarlyView.
The deep paleo‐lake, characterised by low energy and moderate salinity, facilitated the input of fine‐grained minerals and the development of aquatic organic matter. Under the combined influence of the sedimentary environment and material source, mineral‐bound organic matter was formed, which played a crucial role in the enrichment of organic matter ...
Rusi Zuo   +6 more
wiley   +1 more source

Study on damage and failure characteristics of loaded gas‐bearing rock–coal–rock combination structures

open access: yesDeep Underground Science and Engineering, EarlyView.
The influence of gas on the instability and failure of rock–coal–rock combinations is considered. The damage characteristics of gas‐bearing rock–coal–rock combinations under different confining pressures, axial loading rates, and gas are revealed. A constitutive model for gas‐bearing rock–coal–rock damage considering gas is established.
Feng Du   +8 more
wiley   +1 more source

Seismological structure of the 1.8 Ga Trans-Hudson Orogen of North America [PDF]

open access: yes, 2016
Precambrian tectonic processes are debated: what was the nature and scale of orogenic events on the younger, hotter, and more ductile Earth? Northern Hudson Bay records the Paleoproterozoic collision between the Western Churchill and Superior plates—the ∼
Abbott   +62 more
core   +1 more source

Ground vibration isolation using mass scatters: A comparative study with trench barriers and wave‐impeding blocks

open access: yesDeep Underground Science and Engineering, EarlyView.
Ground‐borne vibrations are a frequent source of environmental problems. A full‐scale experiment is conducted to validate a 3D numerical model in order to analyze the efficiency of three methods of isolation. Trench barriers and wave‐impeding blocks are impractical and expensive methods of isolation, but mass scatters appear to be an efficient ...
Mohannad Mhanna   +3 more
wiley   +1 more source

Insights into the influences of biochar on the fate and transport of pesticides in the soil environment: a critical review

open access: yesBiochar
Pesticide misuse and overuse severely pollute agricultural soils, water, and crop yields, harming people and animals. This situation raises serious concerns about environmental pollution on a global scale. As an eco-friendly material for soil remediation,
Gratien Twagirayezu   +6 more
doaj   +1 more source

Elution of Adsorbed n-alkanes by 5Å Molecular Sieve Using Solvent Mixtures for Compound-Specific Hydrogen Isotopic Analysis

open access: yesYankuang ceshi, 2017
The extraction procedure using solvent mixtures has been used to elute n-alkanes adsorped by 5Å molecular sieve and subsequent stable carbon isotope ratio analysis of individual n-alkanes.
CHEN Sha-sha   +4 more
doaj   +1 more source

A benchmark study on mantle convection in a 3-D spherical shell using CitcomS [PDF]

open access: yes, 2008
As high-performance computing facilities and sophisticated modeling software become available, modeling mantle convection in a three-dimensional (3-D) spherical shell geometry with realistic physical parameters and processes becomes increasingly feasible.
Gurnis, Michael   +4 more
core   +1 more source

Optimal mud pressure design using nonlinear failure criteria for wellbores in shaley sedimentary reservoir

open access: yesDeep Underground Science and Engineering, EarlyView.
The present study uses the Modified Mohr‐Coulomb true‐triaxial failure criterion (MMC_TT), which predicts the strength of rock better than the MGC criterion in laboratory true‐triaxial tests to overcome the limitations. Moreover, based on the data from previously published five vertical wells in the Krishna‐Godavari basin (K‐G basin), an empirical ...
Ravindra K. Burnwal, Aditya Singh
wiley   +1 more source

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