The results of experimental studies on carbon nanomaterials production in the plasma of an arc discharge initiated in an open air were presented. The possibility of using waste carbide tools as a catalyst for obtaining quasi-two-dimensional carbon nanostructures by the proposed non-vacuum electric arc method was revealed. It was concluded that the process of synthesis of carbon nanostructures and electric arc processing of waste based on tungsten and cobalt are compatible.
Introduction. The etiology and pathogenesis of cerebral aneurysms are diverse. The rare cause of cerebral aneurysms occurrence is cardioembolism in cases of heart tumors, in particular in myxoma. Cardiac myxoma (from Latin muxa, mucus) is the most common (about 50 %) benign tumor of heart. With untimely diagnosis and absence of the disease treatment, embolisms in cerebral vessels may occur with typical symptoms of ischemic stroke as well as in some cases the myxomal aneurysms may develop. There are several theories of their origin. The myxomal aneurysms of cerebral vessels are more common in women and in the vast majority of cases they develop in carotid basins. In a quarter of cases, the disease onsets as intracranial hemorrhage caused by rupture of an oncotic (myxomal) aneurysm, that significantly exceeds the frequency of ruptures (1–3 % per year) in cases of “normal” bifurcation‑hemodynamic intracranial aneurysms. The mortality rate is 3.4 %. The majority (80 %) of ruptures were observed within 2 years after the diagnosis of cardiac myxoma, and in half (48.6 %) of cases clinically significant episodes of embolism were noted. Timely treatment can prevent the hemor rhagic type of course of these aneurysms. Various methods of treatment are described in the literature: different options for surgical eradication as well as the possibilities of chemotherapy and radiation exposure.Aim. To present a case of successful radical reconstructive endovascular treatment of patient with distal cerebral aneurysm associated with cardiac myxoma, combined with presence of multiple cavernous malformations and also to highlight issues of diagnosis, differential diagnosis and existing treatment options for these diseases.Clinical observation. The article presents a clinical observation of multiple aneurysms associated with myxoma of the heart in combination with multiple cavernous angiomas of the brain. The possibility of reconstructive eradication of distal aneurysm after its transformation from fusiform to saccular is demonstrated. The etiology and pathogenesis of occurrence, the nuances of differential diagnosis, possible methods and the algorithm for choosing a method for treating brain aneurysms associated with myxomas are reflected. The patient underwent reconstructive aneurysm shutdown by embolization with microspirals, which became possible due to the anatomical shape that favored this type of treatment. Conversion to destructive intervention was not required. Due to the natural course of the disease, the patient remains at risk of progression of a distal aneurysm in the basin of the same artery, and therefore it will be observed in dynamics.Conclusion. All patients with cardiac myxomas, both before and in dynamics after their removal, are recommended to perform noninvasive visualization of brain vessels for verification of such complication as metastatic (myxomal) aneurysms. The prognosis in most patients with multiple intracranial aneurysms associated with myxoma is favorable and most aneurysms associated with myxoma are stable. However, in cases with progressive or ruptured aneurysms, surgical treatment options should be considered including microsurgical or endovascular eradication. Radiation and chemotherapy methods may have a certain therapeutic value.
The paper presents the results of experimental studies on the implementation of electric arc synthesis of boron carbide using carbon with different morphology and origin as a feedstock: carbon fibers, flake graphite, carbon obtained by pyrolysis of plant waste, namely, pine sawdust and cedar nuts husks. A feature of the electric arc method used is its implementation using an original plasma reactor using atmospheric air as a working gas medium. Oxidation of feedstock and synthesis products in the working cycle of the reactor is prevented due to the generation of CO and CO2 gases in the reaction zone. The possibility of obtaining a material containing micron and submicron boron carbide crystals in a graphite matrix has been experimentally shown. Also, the paper presents information about the features of the oxidation processes of the obtained materials in comparison with commercial samples of boron carbide. Keywords: boron carbide, electric arc synthesis, carbon fibers, flake graphite, carbon of plant origin.
At present, the cleanliness of the human environment and the improvement of the environmental performance of the technologies used by them are becoming increasingly important. In this regard, the problem of high-quality waste processing has arisen. Existing industrial methods for the destruction, neutralization and disposal of waste (landfills, sorting, earth filling, incineration, biothermal composting do not meet the requirements of environmental legislation. In this work, an atmospheric electric arc reactor was developed for waste disposal.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.