The rolling simulation for cold work metal hardening

This article describes the results of a calculation and experimental analysis of destructive physical phenomena that appear in critical sections of industrial and power-related equipment, and lead to occurrence of various operational damages. It was shown that pipeline welded connections are the sections most prone to crack development, therefore the traditional strength calculations need to be combined with fracture mechanics criteria and thorough materials analysis of flawing and structural imperfection. The cold work hardening technique was proposed as a solution for the problem of critical sections performance property restoration. The technique uses surface plastic deformation phenomenon to change the material’s throughthickness stress distribution. In order to optimise surface hardening for welded connections prone to defect formation, we proposed a simulation for analysing an actual pipeline sections load. To assess the applicability of the simulation results, the cold work hardening technique was developed and introduced using a full-scale test sample for damaged areas of welded connections in ø426×40 vent pipes at Novovoronezh NPP Unit No.5.

Evaluation of some physical performance properties of ultrasonic seaming, conventional seaming and sealing adhesive tape on waterproof polyester knitted fabrics with polyurethane

Ultrasonic seaming has become an important issue in recent years due to its various features. In this study, waterproof polyester knitted fabrics with polyurethane coating were used and the bursting strength, bending property and water permeability property of ultrasonic seaming were examined by changing various parameters. Besides, the ultrasonic seaming method was compared to conventional seaming and adhesive tape application. It is observed that there were high water permeability values generally in ultrasonic seaming and also fabrics with no water penetration were seen in this method, although, in some ultrasonic seaming parameters, values are lower than adhesive tape sealed ones. On the other hand, the bursting strength values of the ultrasonically sewn fabrics are found to be comparable to conventional seam and sealing adhesive tape when the optimum seaming parameters are determined. Also, it can be said that for the bending property according to increasing bending length values in this method compared with the others, ultrasonic seaming may find more usage areas where fabric stiffness is more advantageous. It has been observed that it is important to determine the fabric and ultrasonic sewing parameters according to the required performance property.

Porous Polymer Gel Electrolytes Influence Lithium Transference Number and Cycling in Lithium-Ion Batteries

To improve the energy density of lithium-ion batteries, the development of advanced electrolytes with enhanced transport properties is highly important. Here, we show that by confining the conventional electrolyte (1 M LiPF6 in EC-DEC) in a microporous polymer network, the cation transference number increases to 0.79 while maintaining an ionic conductivity on the order of 10−3 S cm−1. By comparison, a non-porous, condensed polymer electrolyte of the same chemistry has a lower transference number and conductivity, of 0.65 and 7.6 × 10−4 S cm−1, respectively. Within Li-metal/LiFePO4 cells, the improved transport properties of the porous polymer electrolyte enable substantial performance enhancements compared to a commercial separator in terms of rate capability, capacity retention, active material utilization, and efficiency. These results highlight the importance of polymer electrolyte structure–performance property relationships and help guide the future engineering of better materials.

Thermally stable biopolymer composites based on poly(3-hydroxybutyrate) modified with linear aliphatic polyurethanes – preparation and properties

Purpose: Poly(3-hydroxybutyrate) (P3HB) is a biopolymer, but storing products from P3HB causes the deterioration of their properties leading to their brittleness. P3HB has also low thermal stability. Its melting point almost equals its degradation temperature. To obtain biodegradable and biocompatible materials characterized by higher thermal stability and better strength parameters than the unfilled P3HB, composites with the addition of polyurethanes were produced. Methods: The morphology, thermal, and mechanical property parameters of the biocomposites were examined using scanning electron microscopy, thermogravimetric analysis, standard differential scanning calorimetry, and typical strength machines. Results: Aliphatic polyurethanes, obtained by the reaction of 1,6-hexamethylene diisocyanate and polyethylene glycols, were used as modifiers. To check the influence of the glycol molar mass on the properties of the biocomposites, glycols with a molecular weight of 400 and 1000 g/mol were used. New biocomposites based on P3HB were produced with 5, 10, 15, and 20 wt. % content of polyurethane by direct mixing using a twin-screw extruder. The following property parameters of the prepared biocomposites were tested: degradation temperature, glass transition temperature, tensile strength, impact strength, and Brinell hardness. Conclusions: Improvement of the processing property parameters of P3HB-biocomposites with the addition of aliphatic polyurethanes was achieved by increasing the degradation temperature in relation to the degradation temperature of the unfilled P3HB by over 30 °C. The performance property parameters have also been improved by reducing the brittleness compared to the P3HB, as evidenced by the increase in impact strength and the decrease in hardness with an increase in the amount of polyurethane obtained by the reaction of 1,6-hexamethylene diisocyanate and polyethylene glycol with a molecular weight of 400 g/mol (PU400) as modifier.

Bio-Composites Consisting of Cellulose Nanofibers and Na+ Montmorillonite Clay: Morphology and Performance Property

This paper reports the usage of cellulose nanofibers (CNFs) as a continuous nanoporous matrix and nanoclay (NC) as additive to fabricate hybrid films. CNF/Cloisite Na+ nanoclay composite films containing 10–50 wt % of NC were prepared for the study. The effects of NC incorporation and its content on mechanical, wettability and thermal degradation properties were investigated. The results showed that the film had a multilayer structure with gradually deposited CNT-NC hybrid on the filter paper Pure CNF films had higher moduli compared with those from the composite films, as the incorporation of NC decreased hydrogen bonding and networking ability of CNFs, especially at the high NC loading levels. The composite films demonstrated self-extinguishing ability when being exposed to the open flame. Composites with over 35 wt % NC did not burn because of the formation of a protective barrier containing ordered NC platelets. The addition of montmorillonite NC led to increased surface water contact angle, showing enhanced hydrophobicity of the material. During the film’s thermal pyrolysis, the first process occurred between 100 and 200 °C, resulting mainly from the evaporation of absorbed water; the second, between 280 and 350 °C, indicated thermal decomposition of cellulose; and the slow third stage happened from the 350 to 600 °C, representing carbonization. The results demonstrate that the apparent activation energies for all the CNF/NC composites were higher than the pure CNF film. CNF/NC films fabricated in this process are a promising barrier material for packaging applications.

Altered Grey Wolf Optimization and Taguchi Method with FEA for Six-Phase Copper Squirrel Cage Rotor Induction Motor Design

This paper presents an altered grey wolf optimization, the Taguchi method, and finite element analysis (FEA) with two-phase multi-objective optimization for the design of a six-phase copper squirrel cage rotor induction motor (SCSCRIM). The multi-objective optimization design with high-performance property aims to achieve lower starting current, lower losses, lower input power, higher efficiency, higher output torque, and higher power factor. The multi-objective optimization design with high-performance property using the altered grey wolf optimization, the Taguchi method, and FEA in the first-phase program is used for minimizing the starting current, stator iron loss, stator copper loss, and input power. The multi-objective optimization design with high-performance property using the altered grey wolf optimization, the Taguchi method, and FEA in the second-phase program is used for maximizing the efficiency, output torque, and power factor. Finally, the proposed skill with higher performances is evaluated and verified via a two-phase program design and some performance tests.

Grain Size Effects in Selective Laser Melted Fe-Co-2V

The material science of additive manufacturing (AM) has become a significant topic due to the unique way in which the material and geometry are created simultaneously. Major areas of research within inorganic materials include traditional structural materials, shape memory alloys, amorphous materials, and some new work in intermetallics. The unique thermal profiles created during selective laser melting (SLM) may provide new opportunities for processing intermetallics to improve mechanical and magnetic performance. A parameter set for the production of Fe-Co-2V material with additive manufacturing is developed and efforts are made to compare the traditional wrought alloy to the AM version of the same chemistry. Evaluation includes magnetic properties, composition, and phase as a function of thermal history, as well as mechanical performance. Results show significant similarities in microstructure between AM and wrought materials, as well as mechanical and magnetic performance. Property trends are evaluated as a function of grain size and show effects similar to the Hall–Petch strengthening observed in wrought material, though with some underprediction of the strength. Magnetic properties qualitatively follow the expected trends but demonstrate some deviation from wrought material, which is still unexplained.

Mixture of Expert/Imitator Networks: Scalable Semi-Supervised Learning Framework

The current success of deep neural networks (DNNs) in an increasingly broad range of tasks involving artificial intelligence strongly depends on the quality and quantity of labeled training data. In general, the scarcity of labeled data, which is often observed in many natural language processing tasks, is one of the most important issues to be addressed. Semisupervised learning (SSL) is a promising approach to overcoming this issue by incorporating a large amount of unlabeled data. In this paper, we propose a novel scalable method of SSL for text classification tasks. The unique property of our method, Mixture of Expert/Imitator Networks, is that imitator networks learn to “imitate” the estimated label distribution of the expert network over the unlabeled data, which potentially contributes a set of features for the classification. Our experiments demonstrate that the proposed method consistently improves the performance of several types of baseline DNNs. We also demonstrate that our method has the more data, better performance property with promising scalability to the amount of unlabeled data.

Properties of Polysiylate Binders for Sol-Silicate Pains

Information is provided on the composition of polysilicate solutions obtained by mixing liquid glass and silica sol. It was found that the introduction of the sol leads to an increase in the silicate module and contributes to an increase in the fraction of high-polymer fractions of the silicon-oxygen anions. The results of the kinetics of the variation of α-SiO2 and β-SiO2. It is shown, that coatings based on the polysilicate solutions are characterized by faster curing. The was found correlation between the content of high-polymer fractions of silicic anions in a polysilicate solution and the tensile strength of films. Increase in the g-SiO2 content promote increase in the tensile strength of films. The composition of sol silicate paint is developed. Coatings based on paint have a high performance property.