The impact of the COVID-19 pandemic, online-learning on the state of visual system and psychological state of students

The aim of this study: to identify and analyze changes in the lifestyle and psychological sphere of students who are undergoing online training in quarantine isolation due to the COVID-19 pandemic. Material and methods: 160 students were examined for the myopic refraction using the Duochrome Test, as well as shifts in the quality of vision as a result of online learning. All participants were also interviewed to ascertain living conditions and psychological status during domestic learning related to COVID-19 isolation. Result: it was found that 42.5 % participants have myopia, most of them students of 1 and 4 courses (26.5 % and 30.9 %, respectively). 85.6 % respondents noted deterioration in health after long-term visual work with personal computer and/or smartphone. The leading symptoms associated with work on digital displays were: decreased visual acuity and binocular vision disorders (81.9 %), headache (75.6 %), back muscle pain (71.9 %), eyes redness (55.6 %), dry and itchy eyes (45 % of respondents). It has been established what 75.6 % respondents indicated deterioration in their psychological condition as a result of quarantine restrictions: 68.1 % – stress, 48.8 % – emotional instability (irritability), 51.9 % – sleep disorders (insomnia), 16.3 % – depression. It is determined that daily average working time in the conditions of domestic online learning was 6.4±2.6 hours (compared to 4.1±1.7 hours in the pre-quarantine period). Conclusion: revealed deterioration in the quality of vision, general well-being and the psychological sphere of students who are undergoing online quarantine training due to the COVID-19 pandemic

Fullerene Black: Structure, Properties and Possible Applications

This review concerns the fullerene black, a poorly known nano-sized carbon material, the insoluble recidue after extraction of fullerenes from fullerene soot produced by arc evaporation of carbon material (usually graphite) in a helium atmosphere. This by-product of the production of fullerenes, whose yield reaches 80 wt %, is a finely dispersed material with a particle size of 40–50 nm. It includes amorphous carbon, graphitized particles, and graphite. Test reactions showed the presence in the structure of fullerene black of curved surfaces, and, like fullerenes, of alternating non-conjugated simple and double bonds. In addition to the double bonds, its structure includes dangling bonds in the concentration not higher than one per 1200 carbon atoms. This nano-carbon can not be graphitized, enters into the reactions of nucleophilic addition, graphite) in a helium atmosphere. This by-product of the production of fullerenes, whose yield reaches 80 wt %, is a finely dispersed material with a particle size of 40–50 nm. It includes amorphous carbon, graphitized particles, and graphite. Test reactions showed the presence in the structure of fullerene black of curved surfaces, and, like fullerenes, of alternating non-conjugated simple and double bonds. In addition to the double bonds, its structure includes dangling bonds in the concentration not higher than one per 1200 carbon atoms. This nano-carbon can not be graphitized, enters into the reactions of nucleophilic reinforces their surface. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3505

A review of the applications of the Block-chain technology in smart devices and dis-tributed renewable energy grids

In this paper we make a critical review of the existing technology in the smart cities and smart grid paradigms from the security perspective. First we summarize the findings about the evolution of renewable technology over time and in particular the benefits of a Cost reduction potential for solar and wind power in the period 2015-2025.  Then we build from existing sources to highlight different ways for efficiency improvement in solar panel solutions during 1975-2015. Next we analyze growth of the smart metering and smart grid technology in the world.  Also, the existing Blockchain solutions are critically reviewed in regard to cyber infrastructure security. From these findings we conclude that there is an increasing need for developing new Blockchain solutions in the smart grids ecosystem

A Rolling Blockchain for a Dynamic WSNs in a Smart City

Blockchain is one of the most popular topics for discussion now. However, most experts still see this technology as only part of Bitcoin, other crypto-currencies or money transfer systems. Often, new solutions, proposed by young researchers, are blocked by reviewers, only because these solutions can not be used for Bitcoins. However, Blockchain technology is more universal and can be used also in other areas, for example, in IoT, WSN and mobile devices. This paper considers the implementation of Blockchain technology in sensor networks as an element of IoT. The concept of "Rolling Blockchain" was proposed, which can be used to build WSN with the participation of Smart Cars, as nodes of the network. The order of block formation and structure in the chain is proposed and a mathematical model is created for it. We estimate the optimal number of WSN nodes, the number of connections between nodes, for specified network reliability values, was performed

Formation of optimal Boolean functions for analog-digital conversion

[EN] This paper describes a situation in which the function obtained from an analog-to-digital conversion is considered a partially-certain function. In this case it is possible to neglect the least significant bits and therefore redefine them arbitrarily. A realization of proposed method simplifies the further processing of the received signal, and saves hardware consumption at designing and usage of hardware and software systems that include analog-to-digital converters

Blockchain Tree for eHealth

The design of access control mechanisms for healthcare systems is challenging: it must strike the right balance between permissions and restrictions. In this work, we propose a novel approach that is based on the Blockchain technology for storage patient medical data and create an audit logging system able to protect health data from unauthorized modification and access. The proposed method consists of a tree structure: a main chain linked with the patient's identity and one or several Subchains which are used for storing additional critical data (e.g., medical diagnoses or access logs)