Additive Technologies in the Production of Vehicle Rubber with Sensory Properties

Annotation. Rubber products are widely used in the construction of vehicles, for example, as sealing and protective devices, suspension joints and are the basis of automobile tires. Modern trends related to increasing the level of vehicle safety require the use of innovative approaches in the design and use of new materials with unique properties. This article proposes an approach to create a rubber with sensory properties that can be used in various automotive products and prevent situations that can harm both human health and lead to serious damage to the structure of the vehicle itself. We have developed an intelligent vehicle door seal to prevent injury to a person when the door is closed carelessly. The sealant, which reacts to deformation when a foreign body enters the seal site, consists of rubber with the addition of piezoceramic powder and two electrode layers. Each electrode layer has several parallel strip-like electrodes positioned along the perimeter of the seal. This document describes possible applications for rubber products with sensory properties and an additive method for making such rubber with the addition of piezoceramic powder.

The use of the respiratory protective devices by the population during the COVID-19 pandemic

Introduction. Wearing a face mask is an important measure against spread of infection during the COVID-19 pandemic. The purpose of the study was to analyze various aspects of the face masks use by the population during the pandemic. The questioner was used. Results. Almost all respondents (96.4%) wore respiratory protective devices during the pandemic; 91.4% respondents worn face masks visiting grocery stores, pharmacies and medical organizations; 64.0% - visiting non-food trade facilities; 76.9% - travelling by surface transport, and 76.1% - being on the subway. Different types of face masks were used, 93.3% of respondents used disposable medical mask, 25.4% - reusable cloth masks. However, only 44.8% of respondents indicated that their protective equipment was made of non-woven material; 26.1% did not know how many layers their protective equipment contained; about a third of respondents (20.1% - 30.21%) were not able to assess the effectiveness of different types of respiratory protection. A third of the respondents (33.6%) wore a disposable medical mask for 2 hours, 35.2% - more than 2 hours in one day, 28.0% - for several days. Conclusions. Most of the respondents wore the face mask. Disposable medical masks were most commonly used. Requirements for the duration of wearing of face masks were met by about third of the respondents, for the handling - half of the respondents. Spontaneous choice of face mask by respondents confirms the importance of the development of hygiene guideline for choosing the most effective respiratory protection.

Probability-Based Customizable Modeling and Simulation of Protective Devices in Power Distribution Systems

Fused contactors and thermal magnetic circuit breakers are commonly applied protective devices in power distribution systems to protect the circuits when short-circuit faults occur. A power distribution system may contain various makes and models of protective devices, as a result, customizable simulation models for protective devices are demanded to effectively conduct system-level reliable analyses. To build the models, thermal energy-based data analysis methodologies are first applied to the protective devices’ physical properties, based on the manufacturer’s time/current data sheet. The models are further enhanced by integrating probability tools to simulate uncertainties in real-world application facts, for example, fortuity, variance, and failure rate. The customizable models are expected to aid the system-level reliability analysis, especially for the microgrid power systems.

Viscoelastic Polyurethane Foams with Reduced Flammability and Cytotoxicity

Consistent and proper use of respiratory protective devices (RPD) is one of the essential actions that can be taken to reduce the risk of exposure to airborne hazards, i.e., biological and nonbiological aerosols, vapours, and gases. Proper fit of the facepiece and comfort properties of RPDs play a crucial role in effective protection and acceptance of RPDs by workers. The objective of the present paper was to develop viscoelastic polyurethane foams for use in RPD seals characterised by proper elasticity, allowing for the enhancement of the device fit to the face and the capability of removing moisture from the skin in order to improve the comfort of RPD use. Moreover, it was pivotal to ensure the non-flammability of the foams, as well as a simultaneous reduction in their cytotoxicity. The obtained foams were characterised using scanning electron microscopy, infrared spectroscopy, thermogravimetry, and differential scanning calorimetry. Measurements also involved gel fraction, apparent density, compression set, rebound resilience, wettability, flammability, and cytotoxicity. The results are discussed in the context of the impact of modifications to the foam formulation (i.e., flame-retardant type and content) on the desired foam properties. The test results set directions for future works aimed to develop viscoelastic polyurethane foams that could be applied in the design of respiratory protective devices.

Protection of Microgrids

The concept of microgrids goes back to the early years of the electricity industry although the systems then were not formally called microgrids. Today, two types of microgrids can be seen: independent and grid connected. The protection requirement of these two types differs as the protection needs of an independent microgrid are intended for protecting components and systems within the microgrid, whereas a grid connected microgrid demands both internal and external protection. The first part of this chapter is dedicated to independent microgrids. How protection devices such as residual current circuit breakers, miniature and moulded case circuit breakers, and surge protective devices should be selected for an example microgrid is discussed while referring to the relevant standards. In the next section, the protection of a grid connected microgrid is discussed. Particularly, micro-source protection, microgrid protection, loss of mains protection and fault ride-through requirements are discussed while referring to two commonly used distributed generator connection codes. An example with simulations carried out in the IPSA simulation platform was used to explain different protection requirements and calculation procedures. Finally, grounding requirements are discussed while referring to different interfacing transformer connections and voltage source inverter connections.