Effect of Thermal Activation on the Structure and Electrochemical Properties of Carbon Material Obtained from Walnut Shells.

A simple activation method has been used to obtain porous carbon material from walnut shells. The effect of the activation duration at 400 °C in an atmosphere with limited air access on the structural, morphological, and electrochemical properties of the porous carbon material obtained from walnut shells has been studied. Moreover, the structure and morphology of the original and activated carbon samples have been characterized by SAXS, low-temperature adsorption porosimetry, SEM, and Raman spectroscopy.

Prediction of phase composition and mechanical properties Fe-Cr-C-B-Ti-Cu hardfacing alloys: Modeling and experimental Validations.

Alloys of the Fe-Cr-C-B-Ti alloy system are characterized by brittleness, which can be eliminated by the copper alloy, while corrosion resistance and abrasive wear resistance are significantly reduced. In this article, comprehensive investigations are carried out on the microstructure and mechanical properties of the proposed high-copper boron-containing alloy 110Cr4Cu7Ti1VB. Systematic theoretical and experimental studies encompassed thermodynamic calculations in ThermoCALC, production of flux-cored wires for hardfacing and welding, receipt of SEM images, acquisition of load and unload diagrams (discharge) via instrumental indentation on various phases of the deposited metal, and determination of chemical composition at indentation points through local chemical analysis.

Porous Structure and Fractal Dimensions of Activated Carbon Prepared from Waste Coffee Grounds.

The present work reports the results of a systematic study on the evolution of the morphological properties of porous carbons derived from coffee waste using a one-pot potassium-hydroxide-assisted process at temperatures in the range of 400-900 °C. Raw materials and obtained carbons were studied by TG, DTG, SEM and nitrogen adsorption porosimetry. The decomposition temperature ranges for hemicellulose, cellulose and lignin as the main component of the feedstock have been established.

Isotope composition of groundwater and surface waters in the area of the Dombrovsky quarry of Kalush-Golinsk deposit of potassium salts.

Enrichment of heavy isotopes of hydrogen (D, H) and oxygen (О) is observed in water samples collected from open brine storage of Kalush-Golinsky deposit. The brine storage facilities were formed during the operation of the Kalush-Golynsky deposit of potassium salts and after its decommissioning. Enrichment of isotopes is also observed in groundwater samples, collected from wells located along with downstream groundwater from brine storage facilities.

Optical and Mechanical Properties of Layered Infrared Interference Filters.

The design and manufacturing technology of interference-absorbing short-wave filters based on a layered composition of Si-SiO on a sapphire substrate of various shapes was developed. A transition layer of SiO was applied to the surface of the substrate, alternating with layers of Si-SiO with an odd number of quarter-wave layers of materials with high (Si) and low refractive indices (SiO), and the application of an outer layer of SiO as an appropriate control of the materials' thickness. The optical properties of the infrared light filter were studied.

Multiclass Level-Set Segmentation of Rust and Coating Damages in Images of Metal Structures.

This paper describes the combined detection of coating and rust damages on painted metal structures through the multiclass image segmentation technique. Our prior works were focused solely on the localization of rust damages and rust segmentation under different ambient conditions (different lighting conditions, presence of shadows, low background/object color contrast). This paper method proposes three types of damages: coating crack, coating flaking, and rust damage.

Optimization of Technological Parameters of the Process of Forming Therapeutic Biopolymer Nanofilled Films.

The prospects of using biopolymer nano-containing films for wound healing were substantiated. The main components of biopolymer composites are gelatin, polyvinyl alcohol, glycerin, lactic acid, distilled water, and zinc oxide (ZnO) nanoparticles (NPs). Biopolymer composites were produced according to various technological parameters using a mould with a chrome coating.

Microstructure and Wear Characterization of the Fe-Mo-B-C-Based Hardfacing Alloys Deposited by Flux-Cored Arc Welding.

An analysis of common reinforcement methods of machine parts and theoretical bases for the selection of their chemical composition were carried out. Prospects for using flux-cored arc welding (FCAW) to restore and increase the wear resistance of machine parts in industries such as metallurgy, agricultural, wood processing, and oil industry were presented. It is noted that conventional series electrodes made of tungsten carbide are expensive, which limits their widespread use in some industries.

Efficient Model of the Interaction of Elastomeric Filler with an Open Shell and a Chrome-Plated Shaft in a Dry Friction Damper.

The results of a study of the contact interaction of an open shell and a chrome-plated shaft with elastomeric filler installed coaxially are presented. The considered contact system is a model of the original design of the shell damper of dry friction. The design feature is the following: the bearing link of the damper is a thin-walled cylindrical shell with a cut along the generatrix; the working body of the damper is elastomeric filler; a hollow chrome-plated shaft centers the damper elements and allows it to be used in technological processes with the presence of aggressive and abrasive-containing media.

Analytical Modeling of the Interaction of a Four Implant-Supported Overdenture with Bone Tissue.

Today, an interdisciplinary approach to solving the problems of implantology is key to the effective use of intraosseous dental implantations. The functional properties of restoration structures for the dentition depend significantly on the mechanical stresses that occur in the structural elements and bone tissues in response to mastication loads. An orthopedic design with a bar fixation system connected to implants may be considered to restore an edentulous mandible using an overdenture.

Mathematical Modelling of Destabilization Stress Factors of Stable-Elastic Fixation of Distal Trans- and Suprasyndesmotic Fibular Fractures.

Introduction: Specification of possible stress factors destabilizing the fibula stable osteosynthesis by the intramedullary nail with distal blocking and elastic fixation of distal syndesmosis by the thread with endobuttons by mathematical modelling of distal unstable ankle injuries. . We studied the thread tension during the combined stable-elastic fixation of unstable injuries of the ankle joint in cross-syndesmosis fractures of the fibula (B, C Danis-Weber classification), which includes a one-time stable minimally invasive fixation with the intramedullary nail and elastic fixation by the thread with endobuttons.

Smart magnetic nanopowder based on the manganite perovskite for local hyperthermia.

For many medical applications related to diagnosis and treatment of cancer disease, hyperthermia plays an increasingly important role as a local heating method, where precise control of temperature and parameters of the working material is strongly required. Obtaining a smart material with "self-controlled" heating in a desirable temperature range is a relevant task. For this purpose, the nanopowder of manganite perovskite with super-stoichiometric manganese has been synthesized, which consists of soft spherical-like ferromagnetic nanoparticles with an average size of 65 nm and with a narrow temperature range of the magnetic phase transition at 42 °C.

Risk Assessment for the Population of Kyiv, Ukraine as a Result of Atmospheric Air Pollution.

Background: According to the World Health Organization, 92% of the world's population lives in places where air quality levels exceed recommended limits. Recently, Ukraine had the most deaths per every 100,000 people (out of 120 countries) attributed to atmospheric air pollution. High levels of atmospheric air pollution have been observed not only in typically industrial regions, but in Ukraine's capital, Kyiv, as well.

Component-oriented acausal modeling of the dynamical systems in Python language on the example of the model of the sucker rod string.

Typically, component-oriented acausal hybrid modeling of complex dynamic systems is implemented by specialized modeling languages. A well-known example is the Modelica language. The specialized nature, complexity of implementation and learning of such languages somewhat limits their development and wide use by developers who know only general-purpose languages.

Variation of Relief Topography and Hardness of Surface Layers of Materials Due to Impact-Oscillatory Loading.

It was shown previously that cyclic loading can be used to extend the fatigue life of sheet plastic materials subjected to the preliminary impact-oscillatory loading. This type of loading causes dynamic non-equilibrium processes (DNP) in materials, which lead to the formation of dissipative structures in materials and on their surface. The density of these dissipative structures is less than that of the base metal.

Mechanical Properties of Gas Main Steels after Long-Term Operation and Peculiarities of Their Fracture Surface Morphology.

Regularities of steel structure degradation of the "Novopskov-Aksay-Mozdok" gas main pipelines (Nevinnomysskaya CS) as well as the "Gorky-Center" pipelines (Gavrilovskaya CS) were studied. The revealed peculiarities of their degradation after long-term operation are suggested to be treated as a particular case of the damage accumulation classification (scheme) proposed by prof. H.

Composition, Microstructure, and Electrical Properties Control of the Powders Synthesized by Sol-Gel Auto-Combustion Method Using Citric Acid as the Fuel.

Nanocrystalline lithium ferrite Li Fe Mg O powders were synthesized by the sol-gel auto-combustion method from the corresponding metal nitrates using citric acid as fuel.The results from XRD, SEM, and AC electrical conductivity studies are summarized as follows: The results of XRD analysis showed that all the samples were formed in single-phase cubic spinel structure at different annealing temperatures from 300 to 700 °C for 2 h. The lattice parameter was found to decrease on increasing the temperature.