Wear resistance increase of sealings of mud end of pump

In this paper, the qualification and the principle of operation of mud pumps are considered. The analysis of the malfunction of the hydraulic part of the pump is also considered. The importance of the work is due to the fact that it was proposed to introduce a support and sealing part of the cuff made of a material of different hardness. The working conditions of the drilling pump from the adopted drilling technology are also considered. An experiment was conducted with the help of which the dependence of the degree of wear of the seal on time was revealed, depending on the material. The importance of the work is due to the fact that the introduction of the support and sealing part of the cuff from a material of different hardness was proposed.

Thermal Performance Improvement of Double-Pane Lightweight Steel Framed Walls Using Thermal Break Strips and Reflective Foils

The reduction of unwanted heat losses across the buildings’ envelope is very relevant to increase energy efficiency and achieve the decarbonization goals for the building stock. Two major heat transfer mechanisms across the building envelope are conduction and radiation, being this last one very important whenever there is an air cavity. In this work, the use of aerogel thermal break (TB) strips and aluminium reflective (AR) foils are experimentally assessed to evaluate the thermal performance improvement of double-pane lightweight steel-framed (LSF) walls. The face-to-face thermal resistances were measured under laboratory-controlled conditions for sixteen LSF wall configurations. The reliability of the measurements was double-checked making use of a homogeneous XPS single panel, as well as several non-homogeneous double-pane LSF walls. The measurements allowed us to conclude that the effectiveness of the AR foil is greater than the aerogel TB strips. In fact, using an AR foil inside the air cavity of double-pane LSF walls is much more effective than using aerogel TB strips along the steel flange, since only one AR foil (inner or outer) provides a similar thermal resistance increase than two aerogel TB strips, i.e., around +0.47 m2∙K/W (+19%). However, the use of two AR foils, instead of a single one, is not effective, since the relative thermal resistance increase is only about +0.04 m2∙K/W (+2%).

Evolution of Passivity for the Multi-Principal Element Alloy CoCrFeNi with Potential, pH and Exposure in Chloride Solution

The evolution of passivity of the multi-principal element alloy CoCrFeNi was studied as a function of potential, pH and exposure duration in 0.1 M NaCl. It was shown that CoCrFeNi exhibits excellent passivity irrespective of pH, revealing a multi-oxide passive film enriched with Cr(III) oxide. Electrochemical impedance spectroscopy suggests that the passive film thickness and polarisation resistance increase with pH and exposure duration, whereby the growth behavior of the passive film was consistent with the assumptions of the point defect model. X-ray photoelectron spectroscopy analysis suggested that the fraction of Co(II) and Ni(II) oxides in the passive film, and their contributions to the passivity of the alloy, increased with increase in pH of the electrolyte. The present work explores the complex synergy between composition, thermodynamics and kinetics on the resultant passivity of a multi-principal element alloy.

Low Temperature Resistance Increase for Bitumen by Compounding with Tar

In this paper, a conventional road bitumen with penetration grade 100–130 is compounded with tar in order to obtain bitumen with improved low temperature resistance. The low temperature (at −24 °C, −30 °C and −36 °C) resistance of the virgin bitumen and the compounded one is evaluated by testing on a bending beam rheometer. It was found that the optimum compounding (20% of tar by weight) decreases the stiffness essentially (from 18% to 34%), i.e., it increases the low temperature resistance of the bitumen. The stiffness decreases in the compounded bitumen can be explained by quantitative variations in its group chemical composition and molecular fragments. Group chemical composition has been determined by the method of absorption chromatography, and the fragments of molecules are identified by NMR-spectroscopy.

Investigation of the properties of composite materials based on epoxy resins with microsilica additives

The outcomes of studying epoxy-based composite materials supplemented with microsilica are provided in the article. Microsilica was used as a filler. The samples were produced on the epoxy ED-20 basis supplemented with 2, 5 and 10 mas. % of microsilica. The structure and size of finely dispersed filler particles were defined. The obtained composites were tested for resistance to the effect of variable temperatures, corrosive, and abrasion. The study outcomes proved that samples supplemented with 2% of microsilica are more resistant to acid and alkali as well as to petrol than those ones supplemented with 25% of microsilica. Besides the amount of the filler from 2 to 10% doesn’t sufficiently affect the resistance to variable temperatures. When microsilica is added to epoxy resin, it causes scuff resistance increase. The conducted testing proved that the developed composite materials are resistant to the effect of variable temperatures, corrosive, and abrasion. This enables to use these materials as coatings and anti-corrosion protection during machine maintenance.

SWIVEL JOINT WEAR-RESISTANCE INCREASE OF PROCESSING MACHINE MANIPULATORS

The work purpose: the choice of promising design-technological ways to support high indices of wear-resistance and friction costs decrease with regard to conditions of parts operation in swivels. The research methods: the set of tribotechnical researches on wear-resistance, on friction loss and physical and chemical parameters. The novelty: there are offered fundamentals for development of new designs of sliding bearings with increased wear-resistance at the expense of the favorable stressed state formation in functional layers, and also thermal physical and damping indices. Investigation results: support of increased thermal conductivity and thermal capacity increase of the materials under consideration gives possibility to increase considerably the friction unit efficiency in swivels, and also at the expense of thermal power accumulation with structural constituents of materials. Wear-resistance increase in the friction unit is provided with the formation of residual compression stresses in a functional surface layer, and the presence of an expanded spring in the bearing system contributes to the increase of its damping characteristics. Conclusions: the design and technological methods offered for working capacity increase and life increase of swivel parts allow assuring increased mechanical and tribological characteristics to a considerable extent and optimizing thermal modes.

Noninvasive Flow Monitoring in Simple Flow Phantom Using Resistive Strain Sensors

In this paper, we introduce a monitoring method for flow expansion and contraction in a simple flow phantom based on electrical resistance changes in an epidermal strain sensor attached to the phantom. The flow phantom was fabricated to have a nonflat surface and small modulus that are analogous to human skin. The epidermal sensors made of polydopamine and polyvinyl alcohol show sufficient linearity (R = 0.9969), reproducibility, and self-adhesion properties, as well as high sensitivity to small modulus measurements (<1% tensile strain). Pulsatile flow monitoring experiments were performed by placing the epidermal sensor on the flow phantom and measuring the relative changes in resistance by the heartbeat. Experiments were conducted for three types of vessel diameters (1.5, 2, and 3 mm). In each of the experiments, the vessels were divided into Top, Middle, and Bottom positions. Experiments for each position show that the relative changes in resistance increase proportionally with the diameter of the vessel. The vessels located close to the epidermal layer have greater relative electrical changes. The results were analyzed using the Bernoulli equation and hoop stress formula. This study demonstrates the feasibility of a noninvasive flow monitoring method using a novel resistive strain sensor.