Mathematical modeling of contact interaction of two electroelastic half-spaces (without electrode coating of surfaces) in the presence of a hard disk-like inclusion between them and pressure in the area of separation

Based on the use of a rigorous mathematical model that takes into account the connectivity of force and electric fields in electroelastic bodies, the contact interaction of two piezoelectric transversely isotropic half-spaces with different properties under compression (in the presence of a hard disk-shaped inclusion between them and pressure in the material separation region) was studied. The solution to the problem is obtained by representing the general solution of the static equations of the electroelasticity for a transversely isotropic body in terms of harmonic functions, followed by the construction of the boundary value problem of the electroelasticity to the consideration of the integral equation and the expansion of the desired function in a small parameter. As a special case from the constructed analytical expressions, the main parameters of the contact for two elastic transversely isotropic and isotropic half-spaces (with the inclusion between them and pressure in the separation region) are implied. Numerical results were obtained. The influence was studied of the electroelastic properties of half-spaces, the geometric dimensions of the inclusion, and loads on the parameters of the contact interaction of electroelastic bodies.

Investigation of the influence of electrode manufacturers ‘recipes on the production and chemical composition of welding fume particles

The quality of the welded joint, production and chemical composition of welding fume particles in the MMAW process, in addition to the welding parameters, mostly depend on the quality of the coated electrode. As part of the preliminary experimental research of the optimal technological composition of the electrode coating, from the aspect of minimizing welding fume, an experimental research of one class of electrodes, E 42 4 B 32 H5, EN 499/94, standard production program of three manufacturers of welding consumables. The test was performed to examine the influence of the manufacturer’s recipe on the production and chemical composition of welding fume particles.

Long-Term Release of Dexamethasone With a Polycaprolactone-Coated Electrode Alleviates Fibrosis in Cochlear Implantation

Cochlear implantation (CI) is the major treatment for severe sensorineural hearing loss. However, the fibrotic tissue forming around the electrodes reduces the treatment effectiveness of CI. Dexamethasone (DEX) is usually applied routinely in perioperative treatment of cochlear implantation (CI), but its diffusion in the inner ear after systemic administration is limited. In the present study, an electrode coated with polycaprolactone (PCL) loaded with dexamethasone was developed with a simple preparation process to maintain the stability of the electrode itself. The DEX-loaded PCL coating has good biocompatibility and does not change the smoothness, flexibility, or compliance of the implant electrode. Stable and effective DEX concentrations were maintained for more than 9 months. Compared with the pristine electrode, decreasing intracochlear fibrosis, protection of hair cells and spiral ganglion cells, and better residual hearing were observed 5 weeks after PCL-DEX electrode implantation. The PCL-DEX electrode has great potential in preventing hearing loss and fibrosis by regulating macrophages and inhibiting the expression of the fibrosis-related factors IL-1β, TNF-α, IL-4, and TGF-β1. In conclusion, the PCL-DEX electrode coating shows promising application in CI surgery.

The Experimental Study of Innovative Methods Regarding the Removal of Sm(III)

The modern development of the construction materials sector determines the use of rare earth metals (REM) for various purposes. In particular, REM are added as basic alloying elements into magnesium alloys to increase alloy durability and strength. The complex systematic study of structural components and REM interaction are the basis for the phase state monitoring of multicomponent oxide polyfunctional materials. In addition, on the preparatory stage, layers with specified construction material coatings are formed. The paper presents experimental and theoretical results of studies of adsorptive bubble methods in the systems containing Samarium cations and surfactants, namely sodium dodecyl sulphate (NaDS). To identify the process mechanisms and prediction of optimal conditions of metal cations’ removal and separation by extraction, flotation, and ion flotation methods, one should know the pH of metal hydroxo-complexes and pH of the hydrate formation. The possibility of lanthanide ions’ removal (by the example of Samarium ions) by the solvent sublation method with NaDS as a collector and isooctyl alcohol as an extractant was studied. From the obtained experimental data, it was clear that the Sm3+ removal in acidic mediums is practically non-existent. The results obtained in this paper are topical in the production of electrode coating components, welding fluxes, sorbents for nuclear wastewater burial, wastewater treatment, highly porous heat-insulating and fire-resistant materials, cement, and concrete with improved frost resistance.

Study of the influence of the increased carbon content in electrodes on structure and properties of the welding seam during welding of 110G13 steel

The object of research is the effect of the carbon-forming component of coated electrodes for welding and surfacing of Gadfield steel (110G13L and analogs) on the structure and properties of the weld. One of the most problematic areas in the welding and surfacing of high-carbon steel is the high irregularity of the rod and coating melting rates. Therefore, the non-melted part of the coating is literally poured into the weld pool, which leads to significant chemical and structural inhomogeneity of the welded metal. The main hypothesis of the study is the assumption that it is possible to increase the homogeneity of the deposited metal by changing the conditions for the transition of carbon from the electrode to the weld pool by using an electrode rod made of carbon steel. In the course of the study, electrode rods with different carbon contents were used. With an increase in the carbon content in the composition of the electrode rod, the fluidity of the drops increased, which contributed to a decrease in the strength of the welding current without harm to the welding and technological characteristics. This allows to reduce the generation of heat in the base metal, that is an effective measure to prevent hot cracks in the weld metal and heat affected zone Studies of the composition of the electrode metal droplets and the weld material showed that with an increase in the carbon content in the electrode rod from 0.08 % to 0.8 %, the carbon content in the droplets increases from 0.3 % to 0.97 %. The carbon content in the weld metal is 1.1 %. The assimilation of manganese by a drop increases with an increasing of coating and the droplet interaction time. A significant increasing in the rate of coating melting was obtained. This is due to the fact that the concomitant decrease in the content of graphite in the coating contributes to a decrease in the refractoriness of the electrode coating. The use of high carbon steels for the manufacturing of electrode rods for welding and surfacing of Gadfield steel improves the properties of the welded metal and sanitary and hygienic parameters.

Recent Advancements in Polythiophene-Based Materials and Their Biomedical, Geno Sensor and DNA Detection

In this review, the unique properties of intrinsically conducting polymer (ICP) in biomedical engineering fields are summarized. Polythiophene and its valuable derivatives are known as potent materials that can broadly be applied in biosensors, DNA, and gene delivery applications. Moreover, this material plays a basic role in curing and promoting anti-HIV drugs. Some of the thiophene’s derivatives were chosen for different experiments and investigations to study their behavior and effects while binding with different materials and establishing new compounds. Many methods were considered for electrode coating and the conversion of thiophene to different monomers to improve their functions and to use them for a new generation of novel medical usages. It is believed that polythiophenes and their derivatives can be used in the future as a substitute for many old-fashioned ways of creating chemical biosensors polymeric materials and also drugs with lower side effects yet having a more effective response. It can be noted that syncing biochemistry with biomedical engineering will lead to a new generation of science, especially one that involves high-efficiency polymers. Therefore, since polythiophene can be customized with many derivatives, some of the novel combinations are covered in this review.

Experimental investigation on dissimilar weld between super duplex stainless steel 2507 and API X70 pipeline steel

This work investigates the microstructure and mechanical properties of 2507 super duplex stainless steel and API X70 high strength low alloy steel weld joint. This joint finds application in offshore hydrocarbon drilling riser and oil–gas pipelines. Coated shielded metal arc welding electrodes have been designed and extruded on 309L filler and their performance compared with a commercial austenitic electrode E309L. Filler 309L solidifies in ferrite-austenite (F-A) mode with a resultant microstructure comprising skeletal ferrites with austenite distributed in the interdendritic region. Results of tensile and impact tests indicate that weld fabricated with laboratory-developed electrodes has higher ductility and impact energy than the commercial electrode. The tensile strength and weld hardness of commercial electrodes are superior. The laboratory-made electrode’s microhardness is lower than the commercial electrodes, making the former less prone to failure. An alternative welding electrode coating composition has been suggested through this work and found to be performing satisfactorily and comparable to the commercially available electrodes.