scholarly journals Importance of Magmatic Water Content and Oxidation State for Porphyry-Style Au Mineralization: An Example from the Giant Beiya Au Deposit, SW China

Minerals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 441 ◽  
Author(s):  
Xinshang Bao ◽  
Liqiang Yang ◽  
Wenyan He ◽  
Xue Gao
Keyword(s):  
Water Content ◽  
Oxidation State ◽  
Water Saturation ◽  
High Water ◽  
Parent Magma ◽  
High Water Content ◽  
Average Temperature ◽  
Metallogenic Belt ◽  
Magmatic Temperature ◽  
Magmatic Water Content

The Beiya Au deposit is the largest Cenozoic Au deposit in the Jinshajiang-Ailaoshan porphyry metallogenic belt. Numerous studies document that high water content and fO2 are vital factors for the generation of Au mineralization. In this belt, only the Wandongshan and Hongnitang districts are considered to be of economic importance, while the other districts, such as Bailiancun, are barren. So in order to reveal the importance of water content and oxidation state for Beiya porphyry-style Au mineralization, the amphiboles and zircons compositions are used to evaluate the physicochemical conditions (e.g., pressure, temperature, fO2, and water content) of the Wandongshan ore-fertile porphyries and Bailiancun ore-barren porphyries observed in the Beiya Au deposit. The results show that the water content of the Wandongshan parent magma (≤4.11 ± 0.4 wt %) are slightly higher than those of the parent magma at Bailiancun (≤3.91 ± 0.4 wt %), while the emplacement pressure of the Wandongshan parent magma (31.5–68.6 MPa) is much lower than that of the parent magma at Bailiancun (142.3–192.8 MPa), indicating that the Wandongshan magma reached water saturation earlier. In addition, the Wandongshan porphyries crystallized from more oxidized magma (average of ΔFMQ = +3.5) with an average temperature of 778 °C compared to the Bailiancun porphyries (average of ΔFMQ = +1.5) with a mean magmatic temperature of 770 °C. The Ce4+/Ce3+ ratio of zircon in the Wandongshan ore-related intrusions (average Ce4+/Ce3+ of 62.00) is much higher than that of the Bailiancun barren porphyries (average Ce4+/Ce3+of 23.15), which further confirmed Wandongshan ore-related magma is more oxidized than the Bailiancun barren magma. Therefore, melts that are more enriched in water and with a high oxidation state will be more fertile to form an economic porphyry-style Au system.

scholarly journals Experimental Study on Dynamic Tensile Failure of Sandstone Specimens with Different Water Contents

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Ming Li ◽  
Gang Lin ◽  
Wei Zhou ◽  
Xianbiao Mao ◽  
Lianying Zhang ◽  
...  
Keyword(s):  
Crack Propagation ◽  
Water Content ◽  
Water Saturation ◽  
Water Injection ◽  
High Water ◽  
Tensile Failure ◽  
High Water Content ◽  
Dynamic Tensile Strength ◽  
Macroscopic Crack ◽  
Water Contents

Understanding the effect of water saturation on dynamic failure of rocks is of great importance to tunnel excavation at water-rich coal mines and prevention of rock bursts by water injection. Dynamic Brazilian disc tests are performed to study mechanical behaviour of sandstones in this paper. The results indicate that water saturation significantly weakens the dynamic tensile strength of sandstones and increases the specimen strain at which the specimen fails. The damage degree of sandstones reduces gradually with increasing water contents. Failure of the sandstone specimen includes the crack initiation at the center of the specimen, macroscopic crack propagation, and stretch of the macroscopic crack through the specimen. In addition, parallel macroscopic crack propagation is found in the specimen with a low water content. From the observation of fracture sections, microstructures are compact in the specimen with high water contents. This is due to the swell of the kaolinite in the specimen after water saturation. The failure mechanism of microstructures is typical brittle failure in the specimen with a high water content, whereas ductile fracture is found in the specimen with a low water content. Different failure processes of microstructures lead to the differences between mechanical properties and macroscopic failure characteristics of the specimens with various water contents.

Hydrogels as Antibacterial Biomaterials

2018 ◽  
Vol 24 (8) ◽  
pp. 843-854 ◽  
Author(s):  
Weiguo Xu ◽  
Shujun Dong ◽  
Yuping Han ◽  
Shuqiang Li ◽  
Yang Liu
Keyword(s):  
Mechanical Properties ◽  
Drug Delivery ◽  
Tissue Engineering ◽  
Water Content ◽  
Oxygen Permeability ◽  
Structural Diversity ◽  
High Water ◽  
Clinical Applications ◽  
High Water Content ◽  
Biomedical Field

Hydrogels, as a class of materials for tissue engineering and drug delivery, have high water content and solid-like mechanical properties. Currently, hydrogels with an antibacterial function are a research hotspot in biomedical field. Many advanced antibacterial hydrogels have been developed, each possessing unique qualities, namely high water swellability, high oxygen permeability, improved biocompatibility, ease of loading and releasing drugs and structural diversity. In this article, an overview is provided on the preparation and applications of various antibacterial hydrogels. Furthermore, the prospects in biomedical researches and clinical applications are predicted.

Microwave-Induced Thermoacoustic Imaging for Embedded Explosives Detection in High-Water Content Medium

2019 ◽  
Vol 67 (7) ◽  
pp. 4803-4810 ◽  
Author(s):  
Xiong Wang ◽  
Tao Qin ◽  
Yexian Qin ◽  
Ahmed H. Abdelrahman ◽  
Russell S. Witte ◽  
...  
Keyword(s):  
Water Content ◽  
High Water ◽  
Explosives Detection ◽  
High Water Content ◽  
Thermoacoustic Imaging

scholarly journals Deep mantle melting, global water circulation and its implications for the stability of the ocean mass

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Shun-ichiro Karato ◽  
Bijaya Karki ◽  
Jeffrey Park
Keyword(s):  
Phase Transformation ◽  
Water Content ◽  
Sea Level ◽  
High Water ◽  
Water Circulation ◽  
Mantle Melting ◽  
High Water Content ◽  
Mineral Physics ◽  
Deep Mantle ◽  
Global Water

AbstractOceans on Earth are present as a result of dynamic equilibrium between degassing and regassing through the interaction with Earth’s interior. We review mineral physics, geophysical, and geochemical studies related to the global water circulation and conclude that the water content has a peak in the mantle transition zone (MTZ) with a value of 0.1–1 wt% (with large regional variations). When water-rich MTZ materials are transported out of the MTZ, partial melting occurs. Vertical direction of melt migration is determined by the density contrast between the melts and coexisting minerals. Because a density change associated with a phase transformation occurs sharply for a solid but more gradually for a melt, melts formed above the phase transformation depth are generally heavier than solids, whereas melts formed below the transformation depth are lighter than solids. Consequently, hydrous melts formed either above or below the MTZ return to the MTZ, maintaining its high water content. However, the MTZ water content cannot increase without limit. The melt-solid density contrast above the 410 km depends on the temperature. In cooler regions, melting will occur only in the presence of very water-rich materials. Melts produced in these regions have high water content and hence can be buoyant above the 410 km, removing water from the MTZ. Consequently, cooler regions of melting act as a water valve to maintain the water content of the MTZ near its threshold level (~ 0.1–1.0 wt%). Mass-balance considerations explain the observed near-constant sea-level despite large fluctuations over Earth history. Observations suggesting deep-mantle melting are reviewed including the presence of low-velocity anomalies just above and below the MTZ and geochemical evidence for hydrous melts formed in the MTZ. However, the interpretation of long-term sea-level change and the role of deep mantle melting in the global water circulation are non-unique and alternative models are reviewed. Possible future directions of studies on the global water circulation are proposed including geodynamic modeling, mineral physics and observational studies, and studies integrating results from different disciplines.

scholarly journals Torrefaction of Woody and Agricultural Biomass: Influence of the Presence of Water Vapor in the Gaseous Atmosphere

Processes ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 30
Author(s):  
María González Martínez ◽  
Estéban Hélias ◽  
Gilles Ratel ◽  
Sébastien Thiéry ◽  
Thierry Melkior
Keyword(s):  
Water Vapor ◽  
Water Content ◽  
Wheat Straw ◽  
Beech Wood ◽  
High Water ◽  
High Water Content ◽  
Biomass Degradation ◽  
Moist Atmosphere ◽  
Thermochemical Transformation ◽  
Degradation Reactions

Biomass preheating in torrefaction at an industrial scale is possible through a direct contact with the hot gases released. However, their high water-content implies introducing moisture (around 20% v/v) in the torrefaction atmosphere, which may impact biomass thermochemical transformation. In this work, this situation was investigated for wheat straw, beech wood and pine forest residue in torrefaction in two complementary experimental devices. Firstly, experiments in chemical regime carried out in a thermogravimetric analyzer (TGA) showed that biomass degradation started from lower temperatures and was faster under a moist atmosphere (20% v/v water content) for all biomass samples. This suggests that moisture might promote biomass components’ degradation reactions from lower temperatures than those observed under a dry atmosphere. Furthermore, biomass inorganic composition might play a role in the extent of biomass degradation in torrefaction in the presence of moisture. Secondly, torrefaction experiments on a lab-scale device made possible to assess the influence of temperature and residence time under dry and 100% moist atmosphere. In this case, the difference in solid mass loss between dry and moist torrefaction was only significant for wheat straw. Globally, an effect of water vapor on biomass transformation through torrefaction was observed (maximum 10%db), which appeared to be dependent on the biomass type and composition.

Study on Corrosion of X80 Pipeline Steel in Different Water Content of Soil

2014 ◽  
Vol 1015 ◽  
pp. 655-658
Author(s):  
Shu Zhen Yu ◽  
Guang Jun Xu ◽  
Han Hua Song ◽  
Xun Zhu ◽  
Wen We Lu ◽  
...  
Keyword(s):  
Water Content ◽  
High Frequency ◽  
Pipeline Steel ◽  
Electrochemical Corrosion ◽  
High Water ◽  
High Water Content ◽  
Linear Segment ◽  
X80 Pipeline Steel ◽  
The Third ◽  
In The Beginning

The electrochemical corrosion of X80 pipeline steel in Xinzhou’s soil with different water content is tested and analyzed. The corrosion signal time and frequency domain figure show that the corrosion signal fluctuates all the time in 30 days’ test with low water content (14%). The slope of high-frequency linear segment in the potential PSD is smaller than it is at the beginning. In the soil with the middle water content (18%), the intense wave motion lasts for 15 days. The noise fluctuation only exists before the third days when in the high water content soil (22%). After the third day, linear drift can be observed but no transient peak. The slope of high-frequency linear segment changes obviously compared with the situation in the beginning. And the high-frequency white noise appears.

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