Hemodynamics of vascular shunts: trends, challenges, and prospects.

Vascular bypass surgery takes a significant place in the treatment of vascular disease. According to various assessments, this type of surgery is associated with almost 20 % of all vascular surgery episodes (up to 23 % according to the Federal Neurosurgical Center of Novosibirsk). Even though the problem of using of vascular grafts is obvious and natural, many problems associated with them are not still elucidated.

Synthesis of Tungsten Carbides in a Copper Matrix by Spark Plasma Sintering: Microstructure Formation Mechanisms and Properties of the Consolidated Materials.

In this study, the synthesis of tungsten carbides in a copper matrix by spark plasma sintering (SPS) is conducted and the microstructure formation mechanisms of the composite materials are investigated. The reaction mixtures were prepared by the high-energy mechanical milling (MM) of W, C and Cu powders. The influence of the MM time and SPS temperature on the tungsten carbide synthesis in an inert copper matrix was analyzed.

Rheological Properties of Non-Adhesive Embolizing Compounds-The Key to Fine-Tuning Embolization Process-Modeling in Endovascular Surgery.

The study of polymers' rheological properties is of paramount importance both for the problems of their industrial production as well as for their practical application. Two polymers used for embolization of arteriovenous malformations (AVMs) are studied in this work: Onyx-18 and Squid-12. Viscosity curve tests and computational fluid dynamics (CFD) were used to uncover viscosity law as a function of shear rate as well as behavior of the polymers in catheter or pathological tissue models.

Formation of Metal-Oxide Nanocomposites with Highly Dispersed Co Particles from a Co-Zr Powder Blend by Mechanical Alloying and Hydrogen Treatment.

The use of metal powders produced by mechanical treatment in various fields, such as catalysis or gas absorption, is often limited by the low specific surface area of the resulting particles. One of the possible solutions for increasing the particle fineness is hydrogen treatment; however, its effect on the structure of mechanically treated powders remains unexplored. In this work, for the first time, a metal-oxide nanocomposite powder was produced by mechanical alloying (MA) in a high-energy planetary ball mill from commercial powders of Zr and Co in the atomic ratio Co:Zr = 53:47 in an inert atmosphere, followed by high-pressure hydrogenation at room temperature.

The Problem of Filling a Spherical Cavity in an Aqueous Solution of Polymers.

The problem of filling a spherical cavity in a liquid has attracted the attention of many authors. The study of bubble behavior in liquid allows to estimate the consequences of cavitation processes, which can lead to the intensive destruction of the material surface. Regarding this connection, it becomes necessary to study the influence of impurities, including polymeric additives on the strengthening or suppression of cavitation.

A Feasibility Study of High-Entropy Alloy Coating Deposition by Detonation Spraying Combined with Laser Melting.

In this work, a new two-stage approach to the deposition of high-entropy alloy coatings is proposed. At the first stage, a composite precursor coating is formed by detonation spraying of the metal powder mixtures. At the second stage, the precursor coating is re-melted by a laser, and the formation of multi-component solid solution phases can be expected upon solidification.

Numerical Assessment of the Risk of Abnormal Endothelialization for Diverter Devices: Clinical Data Driven Numerical Study.

Numerical modeling is an effective tool for preoperative planning. The present work is devoted to a retrospective analysis of neurosurgical treatments for the occlusion of cerebral aneurysms using flow-diverters and hemodynamic factors affecting stent endothelization. Several different geometric approaches have been considered for virtual flow-diverters deployment.

Core-Shell Particle Reinforcements-A New Trend in the Design and Development of Metal Matrix Composites.

Metal matrix composites (MMCs) are a constantly developing class of materials. Simultaneously achieving a high strength and a high ductility is a challenging task in the design of MMCs. This article aims to highlight a recent trend: the development of MMCs reinforced with particles of core-shell structure.

Elimination of Composition Segregation in 33Al-45Cu-22Fe (at.%) Powder by Two-Stage High-Energy Mechanical Alloying.

In the present work, complex powder alloys containing spinel as a minor phase were produced by mechanical alloying in a high-energy planetary ball mill from a 33Al-45Cu-22Fe (at.%) powder blend. These alloys show characteristics suitable for the synthesis of promising catalysts.

The Relationship between the Strength Characteristics of Cerebral Aneurysm Walls with Their Status and Laser-Induced Fluorescence Data.

Background: Cerebral aneurysms (CA) are a widespread vascular disease affecting 50 per 1000 population. The study of the influence of histological, morphological and hemodynamic factors on the status of the aneurysm has been the subject of many works. However, an accurate and generally accepted relationship has not yet been identified.

Elongated conductive structures in detonation soot of high explosives.

High values of electrical conductivity are obtained at the detonation of condensed high explosives with the formula C H N O . Such values can be explained only in the framework of the contact conductivity hypothesis. In this case, the conductivity is provided by elongated highly-conductive structures which penetrate the whole space of the detonation wave.

Combustion of Titanium-Carbon Black High-Energy Ball-Milled Mixtures in Nitrogen: Formation of Titanium Carbonitrides at Atmospheric Pressure.

In this work, titanium carbonitrides were synthesized by self-propagating high-temperature synthesis (SHS) in nitrogen. For the first time, the synthesis of titanium carbonitrides by combustion was realized in nitrogen at atmospheric pressure. The synthesis was carried out by subjecting high-energy ball-milled titanium-carbon black powder mixtures to combustion in a nitrogen atmosphere.

Fault-tolerant elastic-plastic lattice material.

The paper describes a fault-tolerant design of a special two-dimensional beam lattice. The morphology of such lattices was suggested in the theoretical papers (Cherkaev and Ryvkin 2019 , 485-501; Cherkaev and Ryvkin 2019 , 503-519), where its superior properties were found numerically. The proposed design consists of beam elements with two different thicknesses; the lattice is macro-isotropic and stretch dominated.

Influence of the grain size of high explosives on the duration of a high conductivity zone at the detonation.

At the detonation of condensed explosives, on the profile of electric conductivity is observed the area of high values, which is usually associated with the chemical reaction zone. The new interpretation of experimental data on the electrical conductivity allows one to diagnose the influence of the grain size on the charge structure and the reaction zone in the whole range of densities investigated. The reliability of the proposed hypotheses are investigated by the methods of statistical analysis.

Interaction of a Ti⁻Cu Alloy with Carbon: Synthesis of Composites and Model Experiments.

Titanium carbide (TiC), is the most thermodynamically stable compound in the Ti-C-Cu system, which makes it a suitable reinforcement phase for copper matrix composites. In this work, the interaction of a Ti-Cu alloy with different forms of carbon was investigated to trace the structural evolution leading to the formation of in-situ TiC-Cu composite structures. The reaction mixtures were prepared from TiCu alloy ribbons and carbon black or nanodiamonds to test the possibilities of obtaining fine particles of TiC using ball milling and Spark Plasma Sintering (SPS).

Analysis of the Models of Motion of Aqueous Solutions of Polymers on the Basis of Their Exact Solutions.

The qualitative properties of solutions of a hereditary model of motion of aqueous solutions of polymers, its modification in the limiting case of short relaxation times, and a similar second grade fluid model are studied. Unsteady shear flows are considered. In the first case, their properties are similar to those of motion of a usual viscous fluid.

Fabrication of Porous Materials by Spark Plasma Sintering: A Review.

Spark plasma sintering (SPS), a sintering method that uses the action of pulsed direct current and pressure, has received a lot of attention due to its capability of exerting control over the microstructure of the sintered material and flexibility in terms of the heating rate and heating mode. Historically, SPS was developed in search of ways to preserve a fine-grained structure of the sintered material while eliminating porosity and reaching a high relative density. These goals have, therefore, been pursued in the majority of studies on the behavior of materials during SPS.

The influence of intense ultrasound applied during pressing on the optical and cathodoluminescent properties of conventionally sintered YSZ ceramics.

The aim of the present work was to investigate the effect of the ultrasonic treatment on the optical and cathodoluminescent properties of translucent ZrO-8 mol.% YO (YSZ) ceramics obtained by conventional sintering of the pressed compacts. Treatment by intense ultrasound during dry pressing of the YSZ nanopowder leads to an increase in the relative density, a decrease in the pore size and an increase in the grain size of the sintered ceramics.

Author Correction: Electrical Conductivity Distribution in Detonating Benzotrifuroxane.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.

Electrical Conductivity Distribution in Detonating Benzotrifuroxane.

Electrical conductivity profile behind the detonation front in the benzotrifuroxane (BTF) was measured using high-resolution technique. BTF is a peculiar high explosive which is completely hydrogen-free: its molecular formula is CNO. Results are compared with the conductivity distributions in detonating hexogen (RDX, CHNO) and triaminotrinitrobenzene based explosive (TATB, CHNO).

Globular chitosan treatment of bovine jugular veins: evidence of anticalcification efficacy in the subcutaneous rat model.

Vascular xenografts are widely used in cardiovascular surgery as an alternative to autologous vessels and vascular allografts. Calcification is one of the main drawbacks of vascular grafts, especially among young patients and children. Among different anticalcification approaches, chitosan emerges as a highly promising candidate due to its versatility, natural origin, and biocompatibility.

Formation of Aluminum Particles with Shell Morphology during Pressureless Spark Plasma Sintering of Fe-Al Mixtures: Current-Related or Kirkendall Effect?

A need to deeper understand the influence of electric current on the structure and properties of metallic materials consolidated by Spark Plasma Sintering (SPS) stimulates research on inter-particle interactions, bonding and necking processes in low-pressure or pressureless conditions as favoring technique-specific local effects when electric current passes through the underdeveloped inter-particle contacts. Until now, inter-particle interactions during pressureless SPS have been studied mainly for particles of the same material. In this work, we focused on the interactions between particles of dissimilar materials in mixtures of micrometer-sized Fe and Al powders forming porous compacts during pressureless SPS at 500-650 °C.