scholarly journals PERSPECTIVE DIRECTION OF CALCULATION AND DESIGN OF REINFORCING CARCASSES OF TENSION FIRE HOSES ON BASIS OF SYNTHETIC FIBERS

2018 ◽  
Vol 59 (7) ◽  
pp. 92
Author(s):  
Akerke E. Aripbaeva ◽  
Zhumakhan U. Myrkhalykov ◽  
Oscar I. Koifman ◽  
Yuriy M. Bazarov ◽  
Sergey G. Stepanov
Keyword(s):  
Chemical Properties ◽  
High Strength ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Polyamide 66 ◽  
Synthetic Fibers ◽  
Hydraulic Impact ◽  
Ultrahigh Molecular Weight ◽  
Uhmwpe Fibers ◽  
Physical And Chemical ◽  
Negative Factors

The physical and chemical properties of synthetic fibers of various compositions for reinforcing carcasses of pressure fire fibers, and their appointment and structure were denoted. It is noted that due to the effect of negative factors (mechanical wear, impact of low and high temperatures, the action of sunlight, aging of the material, accidental release of chemically active substances, etc..) on pressure fire hoses at their exploitation, increased demands are imposed on the material of synthetic fibers of pressure fire hoses, the most important of which is resistant to abrasion. The use of pressure fire hoses from polyester fibers based on PET shows that the main reason for breaking up the fibers at their exploitation is abrasion of the surface. In this regard, the use fibers of ultrahigh molecular weight polyethylene (UHMWPE fibers) and fibers of PET, polyamide 66 (PA-66) having high strength and abrasion resistance as a material of reinforcing carcass of pressure fire hoses was proposed. It is extremely important to  develop and improve of the calculation theory and design of fire hoses in hydraulic impact, which will be demand in the calculation and design of new types of pressure fire hoses on the basis of synthetic fibers, as well as to identify reasons for breaking of pressure fire hoses to extinguish the fire, to create a new high-pressure fire hoses. In this regard, the brief analysis of publications on their strength calculation at the hydraulic impact was carried out and achievements in the field of calculation and design of reinforcing carcasses of fire hoses were denoted.

Study of Whiskers to be Used in Composite Materials

2021 ◽  
Vol 316 ◽  
pp. 51-55
Author(s):  
Tamara I. Shishelova ◽  
Vadim V. Fedchishin ◽  
Mikhail A. Khramovskih
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Chemical Properties ◽  
High Strength ◽  
Rapid Expansion ◽  
Physical And Chemical Properties ◽  
Reinforcement Fiber ◽  
Object Of Study ◽  
Physical And Chemical ◽  
And Chemical Properties

Rapid expansion of technologies poses higher requirements to structural materials and items made of them. Conventional materials are being replaced by composite materials (composites). Different additives enhancing the properties of initial materials are used as reinforcement fibers of composites. Utilization of micro-and nanosize particles for production of present-day materials is paid much attention to. Whiskers are among such materials. These crystals have high strength, high chemical and temperature resistance. But for rational utilization of whickers of different chemical composition in composite materials one should know their physical and chemical properties. Objectives of the paper: to study physical and chemical properties of whiskers in different compounds, their composition and structure; to prove experimentally the feasibility of utilizing whiskers as a reinforcement fiber of composite materials. Object of study: specimens of whiskers of silicon nitride (Si3N4), aluminum oxide (Al2O3), aluminum nitride (AlN), and mullite (Al6Si2O13). Methods of investigation: thermal study of specimens, study of mechanical properties and chemical strength, and IR-spectroscopy. Results of study: specimens of whiskers have been studied and their mechanical properties have been tabulated for comparison. Extensive thermal investigation was followed by deduction of regularities and identification of chemical properties of whiskers. IR-spectra of whiskers have been studied and conclusions on molecular composition and on presence of impurities in some whiskers have been made.

Analysis of plasma effect on ultrahigh-molecular weight polyethylene fibers’ surface energy on strength of fibers and fiber reinforced composites

2021 ◽  
Vol 3 ◽  
pp. 42-54
Author(s):  
V. I. Mamonov ◽  
Keyword(s):  
Crystal Structure ◽  
Molecular Weight ◽  
Surface Energy ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Necessary Condition ◽  
Matrix System ◽  
Maximal Load ◽  
Ultrahigh Molecular Weight ◽  
Uhmwpe Fibers ◽  
Fiber Matrix

Completely saturated chemical bonds in ultrahigh-molecular-weight polyethylene (UHMWPE) fibers — are a reason for their low surface energy (FSE), i.e. inert properties. Elongated crystal structure of UHMWPE molecules ensures high anisotropic tensile strength of the fibers. An inertness is a problem for utilization these fibers in high-strength composites production. Surface energy (SE) difference of the fibers and a binder in fiber/matrix system hinders chemical interaction at interphase boundary and worsens fiber wettability. Increase in their FSE is a topical task for this problem decision. Necessary condition of FSE increase is the integrity of molecule structure, lying under modified surface. Low temperature, nonequilibrium plasma (LTP) treatment in a medium of argon and argon/propane mixture, used in this work for plasma activation of fibers’ surface, permits to abide by this condition. However, plasma ion bombardment during a process of activation can modify interior crystal structure and, as a result, decrease their strength. The rovings SK75 (Holland) and D800 (China) were used for study of the properties of UHMWPE fibers after plasma treatment. Activation effect on FSE, strength, and fibers’ wetting by water and epoxy binder before and after ageing was studied. Capillary wetting of the fibers by distilled water used for FSE evaluation. The data of filaments surface structure and their diameter change at maximal load, obtained by optical microscope study, were used for the analysis of FSE and epoxy matrix effect on the strength of fiber/matrix systems. Essential distinction of SK75 and D800 fibers properties is ascertained. Negative effect of fibers’ and matrix’s stiffness, as well as increased FSE of stiff fibers on the strength of fiber/matrix system is revealed.

scholarly journals PLA Composites Reinforced with Flax and Jute Fibers—A Review of Recent Trends, Processing Parameters and Mechanical Properties

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2373 ◽  
Author(s):  
Usha Kiran Sanivada ◽  
Gonzalo Mármol ◽  
F. P. Brito ◽  
Raul Fangueiro
Keyword(s):  
Natural Fibers ◽  
High Strength ◽  
Processing Parameters ◽  
Economic Benefits ◽  
Synthetic Fibers ◽  
Flax Fibers ◽  
Structural Applications ◽  
Technical Features ◽  
Economic Price ◽  
Physical And Chemical

Multiple environmental concerns such as garbage generation, accumulation in disposal systems and recyclability are powerful drivers for the use of many biodegradable materials. Due to the new uses and requests of plastic users, the consumption of biopolymers is increasing day by day. Polylactic Acid (PLA) being one of the most promising biopolymers and researched extensively, it is emerging as a substitute for petroleum-based polymers. Similarly, owing to both environmental and economic benefits, as well as to their technical features, natural fibers are arising as likely replacements to synthetic fibers to reinforce composites for numerous products. This work reviews the current state of the art of PLA compounds reinforced with two of the high strength natural fibers for this application: flax and jute. Flax fibers are the most valuable bast-type fibers and jute is a widely available plant at an economic price across the entire Asian continent. The physical and chemical treatments of the fibers and the production processing of the green composites are exposed before reporting the main achievements of these materials for structural applications. Detailed information is summarized to understand the advances throughout the last decade and to settle the basis of the next generation of flax/jute reinforced PLA composites (200 Maximum).

Temporary-Creep and Postcreep Properties of Aquaculture Netting Materials With UHMWPE Fibers

2016 ◽  
Vol 138 (3) ◽  
Author(s):  
Heidi Moe-Føre ◽  
Per Christian Endresen ◽  
Østen Jensen
Keyword(s):  
Creep Strain ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Tensile Tests ◽  
Test Results ◽  
Elongation At Break ◽  
Creep Properties ◽  
Mean Values ◽  
Ultrahigh Molecular Weight ◽  
Polyester Fibers ◽  
Uhmwpe Fibers

This paper presents test results on temporary-creep properties, recovery of strain postcreep and postcreep tensile properties of a Raschel knitted netting material with a combination of ultrahigh molecular weight polyethylene (UHMWPE) and polyester fibers. Specimens of the material were subjected to uniaxial loading over a period of 30 mins, at a constant creep target load of 10–90% of average tensile strength. The specimens were wet and tested in room temperature. The netting structure experienced creep strain with mean values in the range of 1.3–4.5%, increasing with increased creep target load. In addition, the netting experienced 2% creep strain during on-loading. The creep strains were elastic, while large proportions of the elongation accumulated during on-loading (structural strain of 8.8–27.8%) were long lasting and possibly permanent. Tensile tests showed that for the highest creep target load, strength, and elongation at break increased by 17%.

scholarly journals Unprecedented High-Modulus High-Strength Tapes and Films of Ultrahigh Molecular Weight Polyethylene via Solvent-Free Route

2011 ◽  
Vol 44 (14) ◽  
pp. 5558-5568 ◽  
Author(s):  
Sanjay Rastogi ◽  
Yefeng Yao ◽  
Sara Ronca ◽  
Johan Bos ◽  
Joris van der Eem
Keyword(s):  
Molecular Weight ◽  
High Strength ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Solvent Free ◽  
High Modulus ◽  
Ultrahigh Molecular Weight

scholarly journals Waste heaps in the urban environment as negative factors of urbanization

2021 ◽  
Vol 915 (1) ◽  
pp. 012001
Author(s):  
V Popovych ◽  
A Voloshchyshyn ◽  
P Bosak ◽  
N Popovych
Keyword(s):  
Coal Mining ◽  
Chemical Properties ◽  
Environmental Safety ◽  
Mine Dumps ◽  
Mining Region ◽  
Operating Process ◽  
Secondary Factor ◽  
Physical And Chemical ◽  
Negative Factors ◽  
Polluted Wastewater

Abstract Urbanization in Ukraine has led to the development of the Lviv-Volyn coal basin. One of the main negative factors in the operation of coal basins are mine dumps. In addition to environmental hazards, waste heaps of coal mines violate the attractiveness and aesthetics of towns. The wastewater from waste heaps is a secondary factor in reducing the environmental safety of the coal-mining region. These waters are concentrated at the foot of landfills forming the man-made reservoirs. The research presents the negative factors of mine dumps and the results of physical and chemical analysis of subtericone wastewater and its impact on environmental pollution. It is established that the most polluted is the wastewater from waste heaps of the Mezhyrichanska mine which is caused by its operating process. The man-made polluted wastewater from heaps is a secondary factor in reducing the level of ecological danger of the coal-mining region. These waters are concentrated at the foot of landfills in the form of man-made reservoirs. The aim of the research is to indicate the negative factors of urban waste heaps by studying the physical and chemical properties of underspoil waters within the cities of Chervonograd and Novovolynsk.

scholarly journals PEMAKAIAN FLY-ASH SEBAGAI CEMENTITIOUS PADA BETON MUTU TINGGI DENGAN STEAM CURING (THE USE OF FLY-ASH AS CEMENTITIOUS ON HIGH-STRENGTH CONCRETE WITH STEAM CURING)

2014 ◽  
Vol 10 (2) ◽  
Author(s):  
Erwin Rommel ◽  
Yunan Rusdianto
Keyword(s):  
Fly Ash ◽  
Precast Concrete ◽  
Chemical Properties ◽  
High Strength ◽  
Steam Curing ◽  
Initial Strength ◽  
Speed Up ◽  
Physical And Chemical ◽  
And Chemical Properties

Erwin Rommel1 & Yunan Rusdianto2Jurusan Teknik Sipil Fakultas Teknik Universitas Muhammadiyah MalangAlamat Korespondensi :Jalan Raya Tlogomas 246 Malang 65144email : [email protected] HP 08123314432ABSTRACTThe use of fly-ash as cementitious will be made to utilize physical and chemical properties offly-ash that has a dominan of silica and good of modulus fines. The use of steam curing will be donein this study which can speed up the cycle of making concrete. This is advantageous in the productionof precast concrete and velocity field construction.The research was conducted by making concrete cube 15x15x15 cm for 80 pieces and thentested the compressive strength and absorption of concrete. Achieve the quality of concrete madewith the provision of K600 with giving the fly-ash respectively 7.5%, 15% and 30% by weight ofcement.The results of the research obtained by the use of fly-ash as much as 7.5% as a cementitiousthat was given to the steam curing will provide the initial strength of concrete reached 47% ofcompressive strength at 28 days. While the effect of giving fly-ash in concrete has not seen absorptionsignificantly when compared to concrete without fly-ash.Key word : concrete, fly-ash, steam curing

On the mechanical and morphological properties of highly performant composite laminates based on epoxy resin and oxidized ultrahigh-molecular-weight polyethylene fibers

2020 ◽  
Vol 32 (9) ◽  
pp. 992-1000 ◽  
Author(s):  
Raouf Belgacemi ◽  
Mehdi Derradji ◽  
Abdelrazak Mouloud ◽  
Djalal Trache ◽  
Abdeldjalil Zegaoui ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Epoxy Resin ◽  
Composite Laminates ◽  
High Performance ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Cost Effective ◽  
Polymeric Matrix ◽  
Morphological Properties ◽  
Ultrahigh Molecular Weight ◽  
Uhmwpe Fibers

In this study, new high-performance composite laminates were prepared from epoxy resin and surface modified ultrahigh-molecular-weight polyethylene (UHMWPE) fibers. The UHMWPE fibers underwent two types of chemical modifications, namely through chromic acid and potassium permanganate oxidations. The adopted chemical procedure aimed the grafting of polar groups on the outer surface of fibers for an improved chemical and physical compatibility with the polymeric matrix. The efficiency of the grafting methodology was confirmed by vibrational, thermal, and morphological analyses, and the grafting mechanism was thoroughly discussed. Furthermore, composite laminates were prepared to study the effects of chemical treatments on the mechanical and morphological properties of the resulting composites. The grafting techniques allowed consequent improvements in the tensile and bending properties, up to 34% and 23% for the tensile and flexural strengths, respectively. The study of the fractured surfaces confirmed the exceptional compatibility between the fillers and the polymeric matrix and further corroborated the mechanical findings. Finally, the adopted modification techniques can be regarded as cost-effective and highly suitable for the manufacturing of structural composites for advanced applications.

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