scholarly journals Physical and Mechanical Properties of Deep Oceanic Sediments Cored from the Bottom of Challenger Deep, Mariana Trench

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Xu Dai ◽  
Tao Xu ◽  
Jian Chen
Keyword(s):  
Mechanical Properties ◽  
Deep Sea ◽  
Physical And Mechanical Properties ◽  
High Water Content ◽  
High Plasticity ◽  
High Porosity ◽  
Southwestern Part ◽  
Mariana Trench ◽  
Oceanic Sediments ◽  
Challenger Deep

The deep oceanic sediments were collected from the Challenger Deep in the southwestern part of the Mariana Trench. Considering the salt in the pore water, a modified method for determining the physical and mechanical properties of the deep-sea sediments was proposed, by which the geological engineering indices were measured and corrected. Through the scanning electronic microscope (SEM), the microstructures of the sediments were found to be composed of flocculation, with a large number of diatom debris and empty shells of organism around it. As a consequence, the porosity and compressibility are high; internal friction angle and cohesion are low. Besides high water content, high porosity, high liquid limit, high plasticity, high consolidation coefficient, low compressive modulus, low shear strength, low density, and low specific gravity, the deep-sea mining machine may slip and subside. This research can improve the understanding of the deep-sea sedimentary environment of the Challenger Deep in the southwestern part of the Mariana Trench and provide an essential reference for the parameter calibration as well as the basis for walking-characteristic study and optimization design of the deep-sea mining vehicle.

scholarly journals The Alternatives to Traditional Materials for Subsoil Stabilization and Embankments

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3018 ◽  
Author(s):  
Mirjana Vukićević ◽  
Miloš Marjanović ◽  
Veljko Pujević ◽  
Sanja Jocković
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Power Plants ◽  
Soil Stabilization ◽  
Soft Soil ◽  
Physical And Mechanical Properties ◽  
Engineering Properties ◽  
High Plasticity ◽  
Natural Materials ◽  
Positive Effects

Major infrastructure projects require significant amount of natural materials, often followed by the soft soil stabilization using hydraulic binders. This paper presents the results of a laboratory study of alternative waste materials (fly ash and slag) that can be used for earthworks. Results of high plasticity clay stabilization using fly ash from Serbian power plants are presented in the first part. In the second part of the paper, engineering properties of ash and ash-slag mixtures are discussed with the emphasis on the application in road subgrade and embankment construction. Physical and mechanical properties were determined via following laboratory tests: Specific gravity, grain size distribution, the moisture–density relationship (Proctor compaction test), unconfined compressive strength (UCS), oedometer and swell tests, direct shear and the California bearing ratio (CBR). The results indicate the positive effects of the clay stabilization using fly ash, in terms of increasing strength and stiffness and reducing expansivity. Fly ashes and ash-slag mixtures have also comparable mechanical properties with sands, which in combination with multiple other benefits (lower energy consumption and CO2 emission, saving of natural materials and smaller waste landfill areas), make them suitable fill materials for embankments, especially considering the necessity for sustainable development.

scholarly journals Physical and mechanical properties of composites based on hemp shives and lime

2018 ◽  
Vol 49 ◽  
pp. 00010 ◽  
Author(s):  
Przemysław Brzyski ◽  
Grzegorz Łagód
Keyword(s):  
Mechanical Properties ◽  
Thermal Insulation ◽  
Thermal Conductivity Coefficient ◽  
Positive Impact ◽  
Physical And Mechanical Properties ◽  
Wall Material ◽  
High Porosity ◽  
Plant Origin ◽  
Timber Frame ◽  
Properties Of Composites

One of the objectives of sustainable development in construction is the use of low-processed materials. They have a positive impact on the ecological balance of the building throughout the entire life cycle. Examples of such materials are materials of plant origin - straw, shives, cellulose fibers. They are used as thermal insulation or wall material. In recent years, hemp shives are increasingly used as a component of a lime-based composite, which performs the function of wall filling in timber frame constructions. The shives, due to the high porosity, determine the high thermal insulation properties of the composite. The physico-mechanical properties of the composite can be modified depending on various factors, including the ratio of hemp shives to the binder. The lime binder, in turn, can be modified by hydraulic and pozzolan additives. The paper presents mechanical properties (compressive and flexural strength) as well as physical properties (density, porosity, thermal conductivity coefficient, absorbability) of composites with various proportions of hemp shives of the Bialobrzeskie variety to the lime binder modified with Portland cement and metakaolinite.

Rediscovery of the hadal species Amblyops magnus Birstein & Tchindonova, 1958 (Crustacea: Mysida: Mysidae): first record from the Mariana Trench

Zootaxa ◽  
2018 ◽  
Vol 4402 (1) ◽  
pp. 42 ◽  
Author(s):  
QI KOU ◽  
XINZHENG LI ◽  
LISHENG HE ◽  
YONG WANG
Keyword(s):  
Deep Sea ◽  
First Record ◽  
Japan Trench ◽  
Female Specimen ◽  
Low Latitude ◽  
Mariana Trench ◽  
Mitochondrial Coi ◽  
The Third ◽  
Challenger Deep ◽  
First Time

The blind deep-sea mysid Amblyops magnus Birstein & Tchindonova, 1958 is recorded for the first time from the Mariana Trench based on an adult female specimen collected near the Challenger Deep at a depth of 6555 m. The specimen was described, illustrated and compared with the type description as well as with the materials previously collected from the Japan Trench. The mitochondrial COI barcode was also obtained from the specimen and submitted to GenBank. This is the third discovery of this rare species and significantly extends its geographic distribution range to the low latitude hadal zone. 

scholarly journals Experimental Study on Physical Mechanical Properties and Microstructure of Diatomite Soil in Zhejiang Province, China

2021 ◽  
Vol 12 (1) ◽  
pp. 387
Author(s):  
Lei Gao ◽  
Yi Luo ◽  
Yingeng Kang ◽  
Mingjun Gao ◽  
Omar Abdulhafidh
Keyword(s):  
Mechanical Properties ◽  
Strain Curve ◽  
Physical And Mechanical Properties ◽  
Friction Angle ◽  
Confining Pressure ◽  
Zhejiang Province ◽  
Dry Density ◽  
High Porosity ◽  
Engineering Project ◽  
Geotechnical Tests

Diatomite soil is a kind of bio-siliceous soil with complex composition and special structure, the physical and mechanical properties of diatomite soil are very important for the engineering project. In this paper, the physical properties, mechanical properties, and microstructure of diatomite soil in Zhejiang Province are studied by geotechnical tests and microscopic tests from the macroscopic and microscopic perspective. The results show that: (1) The diatomite soil has special properties different from other soils, including small particle size, low specific gravity value, high liquid-plastic limit, and low compressibility, and the strength indexes c and φ of diatomite soil will decrease with an increase in soil water content; (2) in the triaxial test, when the dry density of diatomite soil increases from 1.30 g/cm3 to 1.50 g/cm3, the effective internal friction angle of diatomite soil increases from 5.6° to 14.5° and the effective cohesion increases from 30.9 kPa to 49.6 kPa. The stress–strain curve of diatomite soil changes from weak softening type to weak hardening type when the confining pressure is above 200 kPa; (3) the diatomite soil has high porosity due to its unique microstructure; it is rich in aluminum oxides and minerals, which will greatly reduce the engineering performance of diatomite soil.

scholarly journals Physical and Mechanical Properties of Composite Scaffolds with or without Collagen Impregnation

2019 ◽  
Vol 9 (20) ◽  
pp. 4296 ◽  
Author(s):  
Marcos ◽  
Perrotti ◽  
Iaculli ◽  
Aragones ◽  
Benfatti ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Energy Dispersive Spectrometer ◽  
Physical And Mechanical Properties ◽  
Bone Tissue Regeneration ◽  
In Vivo Studies ◽  
Biological Behavior ◽  
Control Group ◽  
Mechanical Resistance ◽  
High Porosity

This in vitro study aimed at evaluating the physical and mechanical properties of newly developed scaffolds of poly (lactic-co-glycolic acid) (PLGA) and biphasic ceramic (Hydroxyapatite HA + beta-tricalciumphosphate β-TCP) with or without collagen impregnation to be used for bone regeneration in the oral and maxillofacial district. Solvent casting and particle leaching techniques were used to produce the scaffolds, which were then divided into six groups according to PLGA/HA + β-TCP ratio and impregnation with collagen: G1 (50/50) + collagen; G2 (60/40) + collagen; G3 (40/60) + collagen; G4 (50/50); G5 (60/40); G6 (40/60). As control group, inorganic xenogenous bone was used. Structure and porosity were evaluated by scanning electron microscopy, and a chemical analysis was performed through an energy-dispersive spectrometer. Moreover, to evaluate the hydrophilicity of the samples, a wettability test was conceived, and finally, mechanical properties were examined by a compression test. High porosity and interconnectivity, resulting in a large surface area and great fluid retention capacity, were presented by the PLGA/HA + β-TCP scaffolds. In the composite groups, collagen increased the wettability and the mechanical resistance, although the latter was not statistically affected by the percentage of HA + β-TCP added. Further in vitro and in vivo studies are needed for a deeper understanding of the influence of collagen on the biological behavior of the developed composite materials and their potential, namely biocompatibility and bioactivity, for bone tissue regeneration.

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