STRUCTURAL BONDS DEVELOPMENT IN THE BACKFILL MASS WHEN CHANGING THE DISPERSION OF THE BINDING MATERIAL

Purpose. Theoretical and experimental research on the structural and strength peculiarities of the backfill mass formation during the ore deposits development by activating the binding material of the backfill mixture using fine grinding at the stage of its preparation. Methods. An integrated methodological approach is used, consisting of laboratory studies on determining the properties of backfill mixtures and the structural internal bonds of the backfill mass using scanning electron microscopy. Some laws of the binding material chemistry are used and systematized in the course of theoretical research. Findings. Based on theoretical and experimental research, the interaction and the hydration products of the backfill mixture binding components with water have been studied. The use of a finely ground combined binding material made of slags and limestone improves and strengthens the structural bonds of the backfill mass through a large gap in the covalent bonds of silica and slags, the transition of ions of a weak ionic bond to the formation of other compounds and equalizing the ratio of Si and Са ions in solution. Originality. It has been determined that with an increase in the specific surface area of the binding material particles, the shape of structural new formations of the backfill mass improves, has high strength, and the basicity of its new formations increases. Practical implications. Using the results, it is possible to rationally choose the binding material dispersion, obtain high strength of the backfill mass and increase the stability of its outcropping.

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Experimental research on the stability bearing capacity of Q420 high-strength steel tubular members

Progress in Civil, Architectural and Hydraulic Engineering IV ◽

10.1201/b19383-21 ◽

2015 ◽

pp. 97-101

Author(s):

Buhui Li ◽

Pingzhou Cao ◽

Dachang Zhang ◽

Tao Xu

Keyword(s):

Bearing Capacity ◽

Experimental Research ◽

High Strength Steel ◽

High Strength ◽

Stability Bearing Capacity ◽

The Stability

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Facile Synthesis and Characterization of Palm CNF-ZnO Nanocomposites with Antibacterial and Reinforcing Properties

International Journal of Molecular Sciences ◽

10.3390/ijms22115781 ◽

2021 ◽

Vol 22 (11) ◽

pp. 5781

Author(s):

Janarthanan Supramaniam ◽

Darren Yi Sern Low ◽

See Kiat Wong ◽

Loh Teng Hern Tan ◽

Bey Fen Leo ◽

...

Keyword(s):

Plant Biomass ◽

Cellulose Nanofibers ◽

High Strength ◽

Salmonella Typhi ◽

Particle Sizes ◽

Mechanical Reinforcement ◽

Uniform Size ◽

Preparation Methods ◽

Potential Applications

Cellulose nanofibers (CNF) isolated from plant biomass have attracted considerable interests in polymer engineering. The limitations associated with CNF-based nanocomposites are often linked to the time-consuming preparation methods and lack of desired surface functionalities. Herein, we demonstrate the feasibility of preparing a multifunctional CNF-zinc oxide (CNF-ZnO) nanocomposite with dual antibacterial and reinforcing properties via a facile and efficient ultrasound route. We characterized and examined the antibacterial and mechanical reinforcement performances of our ultrasonically induced nanocomposite. Based on our electron microscopy analyses, the ZnO deposited onto the nanofibrous network had a flake-like morphology with particle sizes ranging between 21 to 34 nm. pH levels between 8–10 led to the formation of ultrafine ZnO particles with a uniform size distribution. The resultant CNF-ZnO composite showed improved thermal stability compared to pure CNF. The composite showed potent inhibitory activities against Gram-positive (methicillin-resistant Staphylococcus aureus (MRSA)) and Gram-negative Salmonella typhi (S. typhi) bacteria. A CNF-ZnO-reinforced natural rubber (NR/CNF-ZnO) composite film, which was produced via latex mixing and casting methods, exhibited up to 42% improvement in tensile strength compared with the neat NR. The findings of this study suggest that ultrasonically-synthesized palm CNF-ZnO nanocomposites could find potential applications in the biomedical field and in the development of high strength rubber composites.

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The Microstructure and Formability Study on DP Steel of Lightweight Automobile

Materials Science Forum ◽

10.4028/www.scientific.net/msf.704-705.1465 ◽

2011 ◽

Vol 704-705 ◽

pp. 1465-1472

Author(s):

Jin Wu ◽

Da Sen Bi ◽

Liang Chu ◽

Jian Zhang ◽

Yun Tao Li

Keyword(s):

Mechanical Property ◽

Work Hardening ◽

High Strength Steel ◽

High Strength ◽

Mathematic Model ◽

Theoretical Research ◽

Forming Limit ◽

Strain Hardening Exponent ◽

Dp Steel ◽

Better Than

Dual phase (DP) steel is a high strength steel for auto-panel. In this paper, mechanical property, forming ability, baked-hardening and work hardening properties of high strength steel DP450 are studied by experiments, and compared with those of steel MS6000.And theoretical research on predicting the forming limit of steel DP450 by the NADDRG model. The established mathematic model for relativity is of practical usefulness. Experimental results reveal that the yield strength of steel DP450 is about 7.2% lower than the MS6000,and the break strength increases by 18.9%,while the elongation increases by 19%.The strain hardening exponent of steel DP450 are superior to those of MS6000.The results show that mechanical property of high strength steel DP450 is better than that of MS6000,while forming ability of DP450 is not lower than that of MS6000.And baked-hardening and work hardening properties of steel DP450 are better than those of MS6000.The steel sheet DP450 owned a good forming ability.

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Laser Welding Dissimilar High-Strength Steel Alloys with Complex Geometries

Metals ◽

10.3390/met8100792 ◽

2018 ◽

Vol 8 (10) ◽

pp. 792 ◽

Cited By ~ 1

Author(s):

Panos Efthymiadis ◽

Khalid Nor

Keyword(s):

Carbon Steel ◽

Laser Welding ◽

Cross Sections ◽

High Carbon Steel ◽

High Strength Steels ◽

High Strength ◽

Low Carbon ◽

High Carbon ◽

Material Chemistry ◽

Metallurgical Defects

Laser welding of dissimilar high-strength steels was performed in this study for two different geometries, flat and circular samples with material thicknesses of 5 and 8 mm. The material combinations were a low carbon to a medium or high carbon steel. Three different welding systems were employed: a Nd:YAG, a CO2 and a fiber laser. The process stability was evaluated for all the experiments. The resulting full penetration welds were inspected for their surface quality at the top and bottom of the specimens. Cross sections were taken to investigate the resulting microstructures and the metallurgical defects of the welds, such as cracks and pores. Significant hardening occurred in the weld region and the highest hardness values occurred in the Heat Affected Zone (HAZ) of the high carbon steel. The occurrence of weld defects depends strongly on the component geometry. The resulting microstructures within the weld were also predicted using neural network-simulated Continuous Cooling Transformation (CCT) diagrams and predicted the occurrence of a mixture of microstructures, such as bainite, martensite and pearlite, depending on the material chemistry. The thermal fields were measured with thermocouples and revealed the strong influence of component geometry on the cooling rate which in term defines the microstructures forming in the weld and the occurring hardness.

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Experimental Research of the Durability, Crack Resistance of the Normal Sections of Bending Elements Produced of Rubber Concrete with Fiber and their Deformability

Materials Science Forum ◽

10.4028/www.scientific.net/msf.931.232 ◽

2018 ◽

Vol 931 ◽

pp. 232-237 ◽

Cited By ~ 2

Author(s):

Aleksei E. Polikutin ◽

Yuri B. Potapov ◽

Artem V. Levchenko

Keyword(s):

Crack Resistance ◽

Experimental Research ◽

High Strength ◽

Strength Characteristics ◽

Material Consumption ◽

Load Bearing ◽

Fiber Concrete ◽

Rubber Concrete ◽

Concrete Elements

The article describes experimental research of bending rubber fiber concrete elements with favorable deformation-strength characteristics. The use of such a material as fiberrubcon in load-bearing structures due to its high strength leads to a decrease in material consumption and weight of structures.

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