Mechanical Characteristics Of Samples Research Articles

Effects of reservoir fluids on sand packs consolidated by furan and epoxy resins: Static and dynamic states

One of the most effective methods for sand control is the chemical consolidation of sandstone structures. In this paper, the impacts of crude oil and brine in the static state and the impact of the flow rates of the fluids in the dynamic state have been assessed at the reservoir conditions. The analyses in this research were Young's modulus, compressive strength, porosity, and permeability which were done on core samples after and before fluid contact. Samples made with two different resins showed good resistance to crude oil in both states. No considerable change was seen in the analyses even at high crude oil injection rates in the dynamic state. Conversely, brine caused a noticeable change in the analyses in both states. In the presence of brine at the static state, Young's modulus and compressive strength respectively decreased by 37.5% and 34.5% for epoxy cores, whereas these parameters respectively reduced by 30% and 41% for furan cores. In brine presence at the dynamic state, compressive strength reduction was 10.28 MPa for furan and 6.28 MPa for epoxy samples and their compressive strength reached 16.75 MPa and 26.54 MPa respectively which are higher than the critical point to be known as weak sandstone core. Moreover, Young's modulus decrease values for furan and epoxy samples were respectively 0.37 GPa and 0.44 GPa. Therefore, brine had a more destructive effect on the mechanical characteristics of samples in the static state than the dynamic one for two resins. In addition, brine injection increased permeability by about 13.6% for furan and 34.8% for epoxy. Also, porosity raised by about 21.8% for furan, and 19% for epoxy by brine injection. The results showed that the chemical sand consolidation weakens in the face of brine production along with crude oil which can lead to increasing cost of oil production and treating wellbore again.

ДРІБНОЗЕРНИСТІ ЗАПОВНЮВАЧІ АСФАЛЬТОБЕТОННИХ СУМІШЕЙ З ПРОДУКТІВ РЕСАЙКЛІНГУ БУДІВЕЛЬНОГО ЛОМУ

The substantiation of the need to develop and implement new resource-saving technologies for the production of construction mixtures using aggregates obtained as a result of complex processing of solid inorganic construction waste is provided. Analytical studies of technogenic waste processing technologies for obtaining building materials have been conducted. The results of the study of the experience of construction scrap processing are presented, with confirmation of the expediency of the fact that the technology of recycling accumulated construction scrap dumps in the territory where the destroyed buildings were located does not require any new specialized measures. The projected volumes of building materials in the composition of residential construction objects with various quantitative parameters of the constituent components of the elements of the fencing structures are presented. Analytical studies have established that the accumulated volumes of construction scrap from the destruction of elements of buildings and structures in the vast majority include the remains of concrete, reinforced concrete, expanded clay concrete, brickwork made of ceramic and silicate products. Experimental series of aggregate samples were made using experimental samples of construction scrap, their granulometric characteristics were determined and physical parameters were investigated. With the use of regulatory and technical literature, the predicted prescription parameters of the concrete mixture using a new variety of aggregates obtained by re-processing of construction scrap were compiled. The presence of reactive substances on the surface of the obtained aggregates was substantiated and the presence of increased physical and mechanical characteristics of the samples with a decrease in the binder content was confirmed. Recipe and technological parameters for the production of wall building materials using the obtained multicomponent building mixtures are proposed. The results of tests of physical and mechanical characteristics of test samples of concrete using aggregates from solid inorganic waste are presented.

ЗАПОВНЮВАЧІ БУДІВЕЛЬНИХ СУМІШЕЙ З ПРОДУКТІВ РЕЦИКЛІНГУ ТВЕРДИХ НЕОРГАНІЧНИХ ВІДХОДІВ

The substantiation of the need to develop and implement new resource-saving technologies for the production of construction mixtures using aggregates obtained as a result of complex processing of solid inorganic construction waste is provided. Analytical studies of technogenic waste processing technologies for obtaining building materials have been conducted. The results of the study of the experience of construction scrap processing are presented, with confirmation of the expediency of the fact that the technology of recycling accumulated construction scrap dumps in the territory where the destroyed buildings were located does not require any new specialized measures. The projected volumes of building materials in the composition of residential construction objects with various quantitative parameters of the constituent components of the elements of the fencing structures are presented. Analytical studies have established that the accumulated volumes of construction scrap from the destruction ofelements of buildings and structures in the vast majority include the remains of concrete, reinforced concrete, expanded clay concrete, brickwork made of ceramic and silicate products. Experimental series of aggregate samples were made using experimental samples of construction scrap, their granulometric characteristics were determined and physical parameters were investigated. With the use of regulatory and technical literature, the predicted prescription parameters of the concrete mixture using a new variety of aggregates obtained by re-processing of construction scrap were compiled. The presence of reactive substances on thesurface of the obtained aggregates was substantiated and the presence of increased physical and mechanical characteristics of the samples with a decrease in the binder content was confirmed. Recipe and technological parameters for the production of wall building materials using the obtained multicomponent building mixtures are proposed. The results of tests of physical and mechanical characteristics of test samples of concrete using aggregates from solid inorganic waste are presented

Mechanical behavior of freeze-cast Ti foams with varied porosity

Titanium (Ti) foams with relative densities of 0.32, 0.37, and 0.49 were processed via freeze casting. The mechanical characteristics of samples with different porosities were studied in uniaxial compression tests at initial strain rates between 0.001 and 0.5 s−1. According to the results, the stress–strain response does not significantly depend on the strain rate, at least up to the applied maximum stress, which corresponds to 0.1–0.3 engineering strain. In-situ acoustic emission (AE) experiments have revealed that the stress drop beyond the maximum stress corresponds to the formation and propagation of macrocracks. However, cracks were also initiated below the maximum stress, particularly, in samples with higher relative densities. The analysis of the Young's modulus and yield strength versus the porosity exhibits a power law relationship with a high exponent (approximately 4–5). This high exponent is reasonable if the decrease in the porosity level is associated with a change in the deformation mechanism from the compression model to the Gibson–Ashby (GA) model between 0.37 and 0.49 relative density.

METHOD OF ASSESSING THE INFLUENCE OF WASHING ON PHYSICO-MECHANICAL INDICATORS OF FABRIC

The article considers an improved method of comprehensive assessment of the impact of washing at home on the physical and mechanical properties of textile materials intended for the manufacture of children’s casual wear. In developing the methodological basis for assessing the change in the properties of fabrics from washing, we used the results of our own observations, which allowed us to analyze the operating conditions of preschool children’s clothing, activities and characteristic movements of children on playgrounds, identify key factors of destruction of products. features, topography of wear, frequency of cleaning from dirt, method of drying, etc. Thus, it can be argued that the shrinkage of fibrous systems depends on a sufficient number of factors that can affect simultaneously and comprehensively, and therefore this process should be classified as multifactorial and difficult to study, as the evaluation method used today is insufficient informative. The maximum allowable norms of such indicators as breaking characteristics up to (-15%) have been established; air permeability coefficient up to (-15%); abrasion resistance on the plane up to (-30%); thickness up to (+20%). The recommended method has been tested experimentally. Evaluation of changes in physical and mechanical characteristics of samples from the impact of repeated processing in the washing bath of a new recipe, close to home, was performed after each wash cycle using informative indicators such as breaking force based on Po, (N) air permeability coefficients Kp (dm3/m2·s) resistance of samples to abrasion in the plane Cs (cycles) and its thickness L (mm). The obtained results show the dependence of all indicators without exception on the number of washing cycles in soap and soda solution, with such as bursting loads of samples, their resistance to abrasion on the plane and air permeability decreases, and thickness increases compared to initial characteristics. The textile material should be considered resistant to the number of washing cycles in the soap and soda solution, which led to a change in at least one of the four criteria to the specified maximum allowable values.

The Evaluation Effect of the Active Lubricating Coating on the Mechanical Properties of Stamped Semi-Finished Products Made of Refractory Metals

We investigated the possibility of using an organofluorine coating on parts of the "Screen" type made by cold stamping from refractory metals, in particular niobium. The paper also presents the results of a study of the mechanical characteristics of samples with acoustic-emission accompaniment and the hardness values before and after applying the organofluorine composition. The surface of parts with and without coating after convolution is studied. It is shown that it is possible to prevent loss of stability during the first operation of the technological process, as well as to reduce the number of operations by eliminating annealing between subsequent operations of drawing with thinning.

Физико-технические свойства глины Корниловского месторождения Томской области

Analytical and laboratory-technological studies of overburden clays of the Kornilovskoye deposit in the Tomsk region have been carried out. The chemical composition, mineral composition, granulometric composition, plasticity and refractoriness of clays have been determined. The sensitivity of clay raw materials to drying, apparent density, water absorption, shrinkage, mechanical characteristics of samples from clay raw materials have been investigated. The possibilities of using clay in various industries are determined.

РЕМОНТ СИЛОВЫХ ГИДРОЦИЛИНДРОВ С ПРИМЕНЕНИЕМ НОВЫХ ПОЛИМЕРНЫХ КОМПОЗИЦИОННЫХ МАТЕРИАЛОВ

The development and implementation of a new repair technology based on the use of polymer parts made of high-performance antifriction composites in tribo-couplings of power hydraulic cylinders will reduce the cost and repair time, significantly increase the reliability of the entire hydraulic system. (Research purpose) The research purpose is in increasing the efficiency of repairing of power hydraulic cylinders of agricultural machinery by restoring tribo-conjugations with new antifriction composites based on modified caprolon. (Materials and methods) The article presents the study of the physical and mechanical characteristics of samples of polymer composites according to well- known and original methods. Authors used computer programs and original methods of equipment suppliers in the study of compounding processes, rheological and tribotechnical tests. Theoretical research using the provisions of theoretical mechanics, elasticity theory and thermophysics has been conducted. A numerical study of the introduction of a spherical indenter into a sample of a viscoelastic composite material was carried out using the ANSYS software package, the MAPDL module. (Results and discussion) The article analyzes the obtained data on the elastic-strength, rheological and tribotechnical characteristics of the studied compositions of polyamide composites. The three-component composite containing 2 percent shungite, 0.5 percent graphite, 6 surfactants has the best complex of these properties. It has been proposed to restore the operability of the piston assembly and the front cover during the repair of the power hydraulic cylinder to change their design with the installation of guide support rings made of polyamide composite into the cover and piston of the hydraulic cylinders. This will lead to a significant reduction in the wear rate of the tribo-coupling parts and reduce the complexity of repairing hydraulic cylinders. (Conclusions) Restoration of tribo-couplings of power hydraulic cylinders with the installation of a guide ring made of a new polymer composite ensures a decrease in the maximum contact stresses, the rate of their increase with an increase in the gap and, as a result, a decrease in the wear rate of the contacted parts.

Захисно-зміцнювальні покриття на арматурних сталях

A conceptually new technology for the application of aluminum coatings on 18G2C steel by the electrolytically deposited NaF-NaCl - AlF3 ionic melt method has been developed. To solve the tasks set in the work, a set of experimental and computational research methods was used: metallographic analysis, energy dispersion microanalysis, mechanical tests, and calculation of the oxidation rate of samples. The mechanical characteristics of the samples of reinforcing steel were determined on a rupture machine FP-100 at an active capture rate of 2.5 mm / min. The relationship between the rates of electrochemical oxidation of the aluminide coating, its mechanical properties, with the distribution of aluminum in the depth of the samples and its phase composition have been determined. The increase of mechanical characteristics of samples from 18G2S steel with an aluminum covering in comparison with usual reinforcing steel is shown. The sequence of structural-phase changes of metal in the process of aluminide coating is determined and its influence on mechanical and corrosion resistance is determined. Experimental evaluation of the rate of oxidation of 18G2C steel samples with aluminum coating under the conditions of sulfuric acid electrolyte at an electric current of 11 to 18 A has been conducted. The developed technology of electrolytic deposition of aluminum has scientific and practical interest for the construction industry. The developed coating makes it possible to increase the mechanical properties of steel by almost 12% and to increase the corrosion resistance. Keywords: aluminum coatings, 18G2C steel, electrochemical oxidation, electrolytic deposition.

Crystalline Design of Cellular Materials

In this study, a new method for generating cellular materials with improved physical and mechanical characteristics is proposed. The mechanical properties of products based on ABS-polymer with topologies, the prototypes of which are isoelectronic surfaces of a number of crystalline substances, are investigated by the method of computer simulation. As an example, in this study, we choose carbon in the crystal structure $$Im\bar {3}m,$$ since its isoelectronic surface is closest in shape to the known topologies of triply periodic minimum energy surfaces (TPMESs). As a result of the study using Autodesk Inventor Professional, the distribution of mechanical stresses, and the appearance of deformed products at various values of the applied mechanical stress are obtained. As a result of the study, strong physical and mechanical characteristics of samples with the proposed geometry are found.

Microstructure and Mechanical Properties of Light Cellular Constructions Made of a VT6 Alloy by Selective Laser Melting

Functional-gradient materials with a variable density can be manufactured by varying a configuration of the base elements of cellular constructions, which is important when designing medicine implants with improved characteristics. The microstructure of cellular elements fabricated by selective laser melting has been studies, and the mechanical characteristics of samples with cellular elements have been determined.

The effect of fiber size on tensile characteristics of natural-fiber-reinforced composites

Composite materials are extensively used in a wide range of applications. Natural-fiber-reinforced polymer matrix composites play a dominant role in the field of composites. The primary objective of this research was to investigate the effect of fiber size on the tensile properties of natural-fiber-reinforced polymer composites. The composite was fabricated by solution-casting technology using jute, coir and banana fibers, varying the fiber ratio as 3, 2 and 1% (weight/weight) and varying the fiber length as 10, 5 and 1 mm. Taguchi’s design of experiments was followed to study the mechanical characteristics of samples by recording Young’s modulus, modulus of resilience and yield stress through tensile tests. Analysis of variance was used to determine the effect of distinctive parameters on the tensile properties through main-effects plots, contour plots and regression equations. It was concluded from the results that the epoxy/jute sample showed good tensile characteristics followed by the epoxy/coir sample. The epoxy/jute sample, with 10 mm size and 3% fiber ratio, exhibited the highest Young’s modulus of 3568 MPa.

Does long-term storage of clay samples influence their mechanical characteristics?

The prime objective of this study is to assess the influence of long-term storage on the physical and mechanical characteristics of clay samples. Samples from two different clays were sealed and stored in a temperature- and humidity-controlled room at the geotechnical laboratory of the Université de Sherbrooke for up to 27 years. The stored clay samples were tested before and after long-term storage and the results compared in this note. The comparison showed that even with long-term storage, the majority of the physical and mechanical characteristics of the samples were preserved.

Formation of 04Cr18Ni9 steel structure and properties during additive manufacturing of blanks

This work presents results of studying specifics of structure and properties of 04Cr18Ni9 steel formation in additive processes, namely, in СМТ (Сold Меtal Тransfer) additive manufacturing and plasma additive manufacturing at reverse polarity current and consumable electrode plasma additive manufacturing (Plasma MIG). The main problem that arises when additive technologies are applied is to ensure that properties of laminates are no lower than those produced using traditional methods. Typical defects of laminates produced by additive manufacturing are increased porosity, nonmetallic inclusions, reduced plasticity, and for high-alloy steels, loss of special properties. The work includes a comparison in structure and mechanical characteristics of materials obtained by CMT additive manufacturing, plasma additive manufacturing at reverse polarity current, and consumable electrode plasma additive manufacturing. It is established that mechanical characteristics of samples made of 04Cr18Ni9 steel obtained by additive manufacturing are no lower than those of steel of similar composition in the deformed state.

Estimation of Changes in Mechanical and Color Properties from the Weight Loss Data of “Shine Muscat” Fruit during Storage

“Shine Muscat” fruit is a table grape commonly consumed cultivar in Japan; however, the storage characteristics have not been investigated, especially physical properties. The objective of this study was to clarify changes in weight loss, mechanical, and color properties of Shine Muscat fruit during storage and the relationships between them. The storage tests were performed at 15°C under two relative humidity (RH) conditions, i.e., RH 95% and RH 40%. The weight loss of fruit was calculated from the mass changes during storage. The mechanical properties—stress, strain, and elasticity—at the break point were examined by compression tests. The color properties, color differences (ΔE), and chroma (C) were calculated from L∗a∗b∗ scale parameters. The breaking stress did not reflect changes in the mechanical characteristics of samples during storage. Weight loss was highly correlated with the breaking strain and elasticity, ΔE, and C. In addition, the physical properties could be estimated from weight loss data (R2 = 0.81–0.94). We showed the changes in weight loss and other physical properties and proposed equations to estimate the physical properties based on weight loss data. The equations indicated the importance of inhibiting the weight loss to maintain the quality and could be used as a nondestructive and easy method for assessment of storage characteristics of Shine Muscat fruit.

Effects of Ageing on the Bond Properties of Carbon Fiber Reinforced Polymer/Concrete Adhesive Joints: Investigation Using a Modified Double Shear Test

Abstract Although externally bonded carbon fiber reinforced polymer (FRP) composites are now commonly used for the strengthening and repair of reinforced concrete structures, the durability of the adhesive bond at the concrete/composite interface is still a matter of investigation and remains a critical issue to be addressed in order to assess the long-term performance of FRP strengthening methods. The proposed paper aimed at presenting the results of an investigation on the time evolution of the adhesive bond strength of concrete/composite assemblies exposed to accelerated ageing. Such an evolution was studied by performing double lap shear tests at several intermediate periods of ageing up to 1 year, while changes in the mechanical properties of the weakest constitutive materials, namely polymer adhesive and concrete, were investigated by means of tensile and compressive tests, respectively. Considering that an increase in the transfer length of aged samples can counterbalance the ageing-induced degradation of the mechanical properties of the bulk adhesive and can finally lead to an unchanged shear capacity of the joint, a new geometry of double-shear test specimens was proposed. This geometry involved a smaller bonded length and consequently restricted the possible increase in transfer length during ageing. Moreover, their reduced size allows the storage of a large number of samples in standard climatic chambers. A specific anchorage device was designed, so that double lap shear tests could be carried out using a conventional universal testing machine. The obtained results showed that the shear tests based on this original setup are able to reveal the evolutions of both the bond strength and the failure mode of concrete/composite assemblies subjected to various accelerated ageing conditions. These ageing conditions were found to have only slight detrimental effects on the mechanical characteristics of samples, and finally a partial recovery was observed.

ASSESSMENT OF MECHANICAL CHARACTERISTICS OF VASCULAR ENDO-PROSTHESES

Titanium nickelide (nitinol) is one of prospective materials for production of special endo-prostheses and other parts and characterized with effect of shape memory. A specific feature of vascular endo-prostheses is the necessity to provide the required rigidity within the temperature interval from 15 to 42 оС. It has been established that titanium nickelide is able to provide the required rigidity but it depends on preliminary heat treatment parameters. So, it is important to determine rela-tions between rigidity of titanium nickelide wire and its preliminary heat treatment parameters for the given temperature in-terval. The aim of the work is to create devices that allow to estimate radial and flexural rigidity of elements made of flexible nitinol wire for manufacturing various medical products, including endo-prostheses of vessels – stents and stent grafts, filter traps. Laboratory digital scales and a specially developed dynamometer based on a cylindrical slotted spring and inductive displacement transducer have been used for measuring a load. The paper proposes possible variants of device designs used to monitor radial rigidity of blood vessel endo-prostheses, as well as to control flexural rigidity of endo-prosthesis elements and wire for their manufacture. The developed devices allow us to evaluate mechanical characteristics of samples under the desired temperature conditions. An introduction of the developed devices has permitted to carry out an operative control on radial and flexural stiffness of intravascular endo-prostheses elements both under conditions of research investigations and during technological process of their manufacture. Currently, the devices are used to specify heat treatment regimes for nitin-ol wire from various manufacturers while manufacturing vascular endo-prostheses.

Effect of Steamed and Non-Steamed Populus deltoides Fiber on the Physical, Mechanical, and Morphological Characteristics of Composites Made from Virgin Polypropylene

The effects of steamed Populus deltoides fiber were studied relative to the physical, mechanical, and morphological characteristics of composites made from virgin polypropylene. Fibers of Populus deltoides were used during the reinforcement phase at 180 °C for 1 h. The tests were carried out with 57% of virgin polypropylene that was combined with 3% of maleic anhydride-modified polypropylene and 40% of wood fiber. The wood fiber portion consisted of either non-steamed fiber, steamed fiber, and an equal mixture of the two kinds of fiber. Mixing was done using an internal mixer at 180 °C and 60 rpm, and the standard samples were constructed by injection molding. Then, the physical and mechanical characteristics of samples were measured. To consider compatibility between the matrix and reinforcement phase, SEM pictures were taken from the break surface of composite samples. The results showed that the composites’ strengths were affected by steam, as components having steamed fibers had the best mechanical strength and dimensional stability, and also the least water absorption and thickness swelling.

Preparation and characterization of clay-based porous ceramics with boric acid as additive

Intention of this work was to obtain porous silicon dioxide ceramics by using boric acid as an inexpensive additive at low forming pressure and low sintering temperature. Starting raw material, smectite clay from surface coal mine Kolubara, Serbia, was purified from organic and inorganic impurities by using heat and chemical treatment. Boric acid was used as binding and sintering aid in amount of 0.5, 1 and 2wt%. Powder was compacted by using different pressures: 40, 60 and 80MPa. Pressed samples were sintered at 850, 1000, 1150, and 1300°C for 4h in air. A relatively high porosity of nearly 40% is obtained for the samples pressed at 40, 60 and 80MPa and sintered at 1000°C. Median pore size diameters are in the range of macroporous up to 0.2μm and 10μm in the samples sintered at 1150 and 1300°C, respectively. X-ray diffraction (XRD), scaning electron microscopy (SEM), and porosimetry measurements were employed to characterize the phases and microstructure of the obtained ceramics. The relations between mechanical characteristics of samples (Young modulus and Poisson ratio) and content of boric acid were studied.

Porous calcium polyphosphate bone substitutes: Additive manufacturing versus conventional gravity sinter processing—Effect on structure and mechanical properties

Porous calcium polyphosphate (CPP) structures proposed as bone-substitute implants and made by sintering CPP powders to form bending test samples of approximately 35 vol % porosity were machined from preformed blocks made either by additive manufacturing (AM) or conventional gravity sintering (CS) methods and the structure and mechanical characteristics of samples so made were compared. AM-made samples displayed higher bending strengths (≈1.2-1.4 times greater than CS-made samples), whereas elastic constant (i.e., effective elastic modulus of the porous structures) that is determined by material elastic modulus and structural geometry of the samples was ≈1.9-2.3 times greater for AM-made samples. X-ray diffraction analysis showed that samples made by either method displayed the same crystal structure forming β-CPP after sinter annealing. The material elastic modulus, E, determined using nanoindentation tests also showed the same value for both sample types (i.e., E ≈ 64 GPa). Examination of the porous structures indicated that significantly larger sinter necks resulted in the AM-made samples which presumably resulted in the higher mechanical properties. The development of mechanical properties was attributed to the different sinter anneal procedures required to make 35 vol % porous samples by the two methods. A primary objective of the present study, in addition to reporting on bending strength and sample stiffness (elastic constant) characteristics, was to determine why the two processes resulted in the observed mechanical property differences for samples of equivalent volume percentage of porosity. An understanding of the fundamental reason(s) for the observed effect is considered important for developing improved processes for preparation of porous CPP implants as bone substitutes for use in high load-bearing skeletal sites.