scholarly journals Laboratory Study of Deformation Behaviour of Two New Reinforcing Polymeric TSLs and Their Potential Application in Deep Underground Coal Mine

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2205
Author(s):  
Han Liang ◽  
Jun Han ◽  
Chen Cao ◽  
Shuangwen Ma

Thin spray-on liner (TSL) is a surface protection technology used by spraying a polymer film, which is widely used for mine airtightness and waterproofing. A reinforcing TSL can replace steel mesh, which is a new method for roadway support. This paper reviews the development of a reinforcing TSL. Considering the deterioration of geological conditions in deep underground mining and the demand for reinforcing automation, two kinds of polymeric reinforcing TSL (RPTSL) materials are developed. The mechanical characteristics of the new TSL materials are studied experimentally. Results show that the average compressive strength, tensile strength, cohesion, and internal friction angle of the two TSL materials are 52 and 32 MPa, 12 and 8 MPa, 6.2 and 17.2 MPa, and 33.6° and 25.9°, respectively. The bonding strength between the two materials and coal is greater than the tensile strength of coal itself, and the mechanical properties of the material for comparison are lower than those of both materials. Based on the TSL support mechanism, we examine the application of the two TSL materials to the mining environment and compare the mechanical properties of polymer materials and cement-based materials. The advantages of polymer materials include versatile mechanical properties, good adhesion, and high early strength. This study provides a new support material to replace steel mesh for roadway surface support, which satisfies the needs of different surface support designs under complex geological conditions, and promotes the automation of roadway support.

2017 ◽  
Vol 2017 ◽  
pp. 1-9
Author(s):  
Jong Won Kim ◽  
Joon Seok Lee

Polyethylene is one of the most commonly used polymer materials. Even though linear low density polyethylene (LLDPE) has better mechanical properties than other kinds of polyethylene, it is not used as a textile material because of its plastic behavior that is easy to break at the die during melt spinning. In this study, LLDPE fibers were successfully produced with a new approach using a dry-jet wet spinning and a heat drawing process. The fibers were filled with carbon nanotubes (CNTs) to improve the strength and reduce plastic deformation. The crystallinity, degree of orientation, mechanical properties (strength to yield, strength to break, elongation at break, and initial modulus), electrical conductivity, and thermal properties of LLDPE fibers were studied. The results show that the addition of CNTs improved the tensile strength and the degree of crystallinity. The heat drawing process resulted in a significant increase in the tensile strength and the orientation of the CNTs and polymer chains. In addition, this study demonstrates that the heat drawing process effectively decreases the plastic deformation of LLDPE.


2019 ◽  
Vol 2 (1) ◽  
pp. 37
Author(s):  
Akash Talapatra

Nowadays a viable development of polymer based material as an alternative to the steel mesh material has been increased at a notable amount for providing enough support in the underground roadways. This feasibility study done on the development of using polymer based alternative is related with both of the chemical & physical properties of the selected material. If the polymer alternative has a considerable amount of capability to tolerate all the physical & material constraints equal to or above the normal steel mesh, then the possibility of using polymeric alternatives have been increased at a greater extent. For this reinforcement test, an experiment practice would be done by comparing the mechanical properties of the steel mesh with the polymeric material such as modulus property, elongation-at-break, yield stress etc. After that, a suitable polymer based alternative will be applied for underground roadway support in upcoming days.


2020 ◽  
Vol 168 ◽  
pp. 00064
Author(s):  
Serhii Skipochka ◽  
Viktor Serhiienko ◽  
Volodymyr Amelin ◽  
Oleh Sytnichenko ◽  
Thibault Faucher

Mining technological solutions for underground mining of offbalance gypsum reserves in difficult mining and geological conditions were justified. An analysis of typical geological disturbances of gypsum seams is carried out using the Artemivsk deposit (Ukraine) as an example. Physical and mechanical properties of rocks in disturbed zones are determined. A quantitative assessment of strength characteristics of rocks during their moistening is carried out. The minimum permissible values of the width of the tape pillar and the power of the protective stack above the camera in the presence of a violation in the roof are calculated. The use of selective mining of the lower part of the seam by combines of the “Roadheader” type is recommended. The maximum width and height of the chamber are determined by the type of combine. The technology has been tested and realized at the gypsum mine of the Additional Liability Company “Siniat”.


Author(s):  
Biao Su ◽  
Heidi Moe Føre ◽  
Eduardo Grimaldo

Abstract This paper presents a comparative study of mechanical properties of biodegradable PBSAT (polybutylene succinate co-adipate-co-terephthalate) and conventional polyamide (PA) gillnets used in Norwegian fisheries. Field tests were performed to simulate abandoned, lost, or otherwise discarded fishing gear. Changes in mechanical properties of PBSAT and PA nets in two Norwegian coastal environments were studied. Samples of biodegradable PBSAT gillnets and PA gillnets were placed inside modified lobster pots at four different locations: two outside the island Hitra in the middle of Norway and two outside Tromsø in the north of Norway. For each pot, seawater temperature was logged each hour, and net samples were retrieved for analyses at 3 to 9 months intervals. Tensile strength testing was performed to determine and compare mechanical properties of biodegradable and PA monofilaments and gillnets. Comparative analyses were conducted, aimed at investigating the different behaviors of biodegradable material and conventional PA material, and the possible influence of seawater temperature on the degradation process of biodegradable PBSAT gillnets. Reduced tensile strength and elongation at break, and a slight increase in stiffness was observed for both PA and PBSAT monofilaments after the field trial at Hitra, indicating degradation of both polymer materials. After 25 months immersion in seawater, the PBSAT gillnets exhibited a significant reduction of tensile strength due to seawater exposure (35%), and the tensile strength of PBSAT gillnets was then 26% lower than the average strength of the PA net samples.


Author(s):  
Oleksii Derkach ◽  
◽  
Oleh Kabat ◽  
Dmytro Makarenko ◽  
Borys Kharchenko ◽  
...  

The purpose of the work is to study and determine material "TEKRONE" belonging to the group of polymers, substantiate such a polymer composite material (PCM) in the modernization of the plow blade, which is not inferior to the "TEKRONE" composite and is much cheaper. This requires the study of the physical and mechanical properties of the material. The following studies of the physical and mechanical properties of the "TEKRONE" material have been conducted: density, heat endurance, and tensile strength. It has been found out that when heated over an open flame, the polymer softens with subsequent melting. There is no charring, destruction in the solid state. Therefore, the TEKRONE material is a thermoplastic. After pyrolytic decomposition 0.5… 0.7% of the initial sample weight remains. PCM TEKRONE density is 954 kg/m3. The value of this parameter coincides with the polyethylene density, which, depending on the brand, varies from 910 to 980 kg/m3. The tensile strength stress of the investigated samples of PCM TEKRONE is 17.9 MPa, which is very close to the values of polyethylene (14.8-17.0 MPa). The laboratory studies have shown that TEKRONE polymer-composite material in its properties corresponds to the materials based on polyethylene. It is determined that the closest in properties are PE 500 and PE 1000 polyethylene. It is advisable to recommend the use of PE 500 and PE 1000 polyethylene as a basis for the manufacture of plow blade of PLN type.


Fire Safety ◽  
2021 ◽  
Vol 38 ◽  
pp. 18-23
Author(s):  
P. Pastuhov ◽  
V. Petrovskii ◽  
O. Lavrenyuk ◽  
B. Mykhalitchko

Introduction. The rapid growth of production rates and the use of polymer materials in various fields has brought about an increase in the number of fires caused by the ignition of polymer products. Among the most common polymer materials are materials based on epoxy resins. They are used in such industries as construction, electrical engineering and radio engineering, shipbuilding, mechanical engineering, including automotive, aerospace and rocketry, etc. Due to its organic structure, high content of carbon and hydrogen, epoxy polymers are very combustible. Their combustion is characterized by high temperature and more flame propagation rate. And it is accompanied by significant smoke formation and the release of large amounts of toxic products. Therefore, the search for new ways to reduce combustibility and maintain the proper level of performance is one of the priorities in the development and implementation of new epoxy polymer materials in various fields. Purpose. The work aims to obtain epoxy-amine composites and to discover the effect of flame retardant-hardener on their fire hazard and physical and mechanical properties.Methods. In work used Modern research methods. The flame propagation rate was determined by UL94, the coefficient of smoke was measured by ASTM E662-19, physical and mechanical properties were evaluated by measuring parameters such as surface hardness, tensile strength, water absorption and chemical resistance.Results. The parameters of fire danger of epoxy-amine composites with different content of flame retardant (0, 5, 16 and 80 mass parts) were studied. The results of experimental studies showed that the flame propagation rate and the smoke formation coefficient in the mode of smouldering and combustion are minimal for epoxy-amine composites containing 16 and 80 mass parts of flame retardant. Such compositions have higher surface hardness and tensile strength. And they also well as more resistant to water and aggressive environments compared to unmodified ones.Conclusion. The paper presents a simple and commercially attractive method of obtaining epoxy-amine composites con-taining different amounts of flame retardant – copper(II) sulfate. It is necessary, the obtained samples of the composites are homogeneous in structure. These should be considered as individual chemicals, not as mixtures. Chemical bonding of all components of the composites, namely the appearance of additional (compared to the unmodified composite) Cu(II)–N coordination bonds in the polymer framework DGEBA/DETA-CuSO4, is reflected in the enhanced physical and mechanical properties and fire hazard reduction for this type of composite materials.


Author(s):  
S. Fujishiro

The mechanical properties of three titanium alloys (Ti-7Mo-3Al, Ti-7Mo- 3Cu and Ti-7Mo-3Ta) were evaluated as function of: 1) Solutionizing in the beta field and aging, 2) Thermal Mechanical Processing in the beta field and aging, 3) Solutionizing in the alpha + beta field and aging. The samples were isothermally aged in the temperature range 300° to 700*C for 4 to 24 hours, followed by a water quench. Transmission electron microscopy and X-ray method were used to identify the phase formed. All three alloys solutionized at 1050°C (beta field) transformed to martensitic alpha (alpha prime) upon being water quenched. Despite this heavily strained alpha prime, which is characterized by microtwins the tensile strength of the as-quenched alloys is relatively low and the elongation is as high as 30%.


2019 ◽  
Vol 14 (1) ◽  
pp. 110
Author(s):  
Assiss. Prof. Dr. Sabiha Mahdi Mahdi ◽  
Dr. Firas Abd K. Abd K.

Aim: The aimed study was to evaluate the influence of silver nitrate on surfacehardness and tensile strength of acrylic resins.Materials and methods: A total of 60 specimens were made from heat polymerizingresins. Two mechanical tests were utilized (surface hardness and tensile strength)and 4 experimental groups according to the concentration of silver nitrate used.The specimens without the use of silver nitrate were considered as control. Fortensile strength, all specimens were subjected to force till fracture. For surfacehardness, the specimens were tested via a durometer hardness tester. Allspecimens data were analyzed via ANOVA and Tukey tests.Results: The addition of silver nitrate to acrylic resins reduced significantly thetensile strength. Statistically, highly significant differences were found among allgroups (P≤0.001). Also, the difference between control and experimental groupswas highly significant (P≤0.001). For surface hardness, the silver nitrate improvedthe surface hardness of acrylics. Highly significant differences were statisticallyobserved between control and 900 ppm group (P≤0.001); and among all groups(P≤0.001)with exception that no significant differences between control and150ppm; and between 150ppm and 900ppm groups(P>0.05).Conclusion: The addition of silver nitrate to acrylics reduced significantly the tensilestrength and improved slightly the surface hardness.


2020 ◽  
Vol 14 (2) ◽  
pp. 6734-6742
Author(s):  
A. Syamsir ◽  
S. M. Mubin ◽  
N. M. Nor ◽  
V. Anggraini ◽  
S. Nagappan ◽  
...  

This study investigated the combine effect of 0.2 % drink cans and steel fibers with volume fractions of 0%, 0.5%, 1%, 1.5%, 2%, 2.5% and 3% to the mechanical properties and impact resistance of concrete. Hooked-end steel fiber with 30 mm and 0.75 mm length and diameter, respectively was selected for this study.  The drinks cans fiber were twisted manually in order to increase friction between fiber and concrete. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the strength performance of concrete, especially the compressive strength, flexural strength and indirect tensile strength. The results of the experiment showed that the combination of steel fibers and drink cans fibers improved the compressive strength, flexural strength and indirect tensile strength by 2.3, 7, and 2 times as compare to batch 1, respectively. Moreover, the impact resistance of fiber reinforced concrete has increase by 7 times as compared to non-fiber concretes. Moreover, the impact resistance of fiber reinforced concrete consistently gave better results as compared to non-fiber concretes. The fiber reinforced concrete turned more ductile as the dosage of fibers was increased and ductility started to decrease slightly after optimum fiber dosage was reached. It was found that concrete with combination of 2% steel and 0.2% drink cans fibers showed the highest compressive, split tensile, flexural as well as impact strength.    


Alloy Digest ◽  
2000 ◽  
Vol 49 (1) ◽  

Abstract Kaiser Aluminum Alloy 7050 has very high mechanical properties including tensile strength, high fracture toughness, and a high resistance to exfoliation and stress-corrosion cracking. The alloy is typically used in aircraft structural parts. This datasheet provides information on composition, physical properties, hardness, tensile properties, and shear strength as well as fracture toughness and fatigue. It also includes information on forming, heat treating, machining, and joining. Filing Code: AL-366. Producer or source: Tennalum, A Division of Kaiser Aluminum.


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