Advances in Science and Technology Research Journal
A firefighter's helmet is used as a basic personal protective equipment item. The purpose of the ... more A firefighter's helmet is used as a basic personal protective equipment item. The purpose of the helmet is to absorb a part of mechanical impact acting towards the rescuer's cervical spine, which may lead to its injury. The aim of the study was to determine the effect of changes in the helmet design on the threshold passive forces transferred to the firefighter's cervical spine. The test subjects were firefighter's helmets compliant with the European standard for helmets used by fire brigades. The study was carried out under model conditions, using special equipment with a head model and an additional force sensor placed under it, where the cervical spine is anatomically located. The central impact energy was assumed to be 60 J. A semi-spherically ended beater was used. The experimentally determined force-displacement characteristics revealed two phases of force increase. Using polyurethane foam as a cushioning insert instead of the expanded polyester used in older designs reduced values of forces in the first phase of the characteristic. There were many cases where the critical passive force value was exceeded, which would have resulted in the cervical spine injury. Modifications in material selection and component manufacturing technology affect the protective capabilities of firefighter's helmets and result in their improvement. Nevertheless, helmets that are currently in use are still affected by forces whose values exceed the ones that are considered to be safe for a firefighter.
Analysis of biomass influence on chosen explosibility parameters of bituminous coal dust Analiza wypływu biomasy na wybrane parametry wybuchowości pyłu węgla kamiennego
Growing share of renewable sources of energy in recent years was forced by national legislations ... more Growing share of renewable sources of energy in recent years was forced by national legislations of various countries willing to reduce carbon dioxide emission originated from fossil fuels. However, growing number of dust explosions have been recorded, for which co-firing of coal and biomass has been blamed. Multiple research works have been therefore conducted to understand the differences in explosion indices of both biomass and coal dusts. Presented research work aims mainly at determining minimal ignition energy and resistivity of selected biomass dust samples and analyzing its possible impact on biomass implementation into coal power plants.
Celem artykułu jest budowanie świadomości na temat zagrożeń spowodowanych przez wyładowania elekt... more Celem artykułu jest budowanie świadomości na temat zagrożeń spowodowanych przez wyładowania elektrostatyczne w środowisku pracy. Przedstawiono wytłumaczenie zjawiska, wskazując metody generowania ładunku elektrycznego na powierzchni obiektów fizycznych. Przybliżono podział wyładowań, a także omówiono wybrane typy: iskrowe, koronowe, snopiaste, snopiaste rozprzestrzeniające się. Przeprowadzono analizę rzeczywistych zdarzeń, w których doszło do powstania wyładowania elektrostatycznego w warunkach przemysłowych, wraz ze wskazaniem przyczyny zjawiska i środków ochronnych. Zagrożenia, które towarzyszą zjawisku elektryczności statycznej wymuszają stosowanie określonych środków bezpieczeństwa. Jak pokazuje praktyka, zaniedbania w tym zakresie mogą powodować ogromne straty, zarówno z punktu widzenia zdrowia i życia pracowników, utraconego i zniszczonego mienia, jak i wpływu na środowisko naturalne. Słowa kluczowe: elektrostatyka, zagrożenie pożarowe, zagrożenie wybuchem, bezpieczeństwo procesowe Electrostatic phenomena in the work environment-hazards analysis and case study The purpose of the article is to build awareness about the hazards caused by electrostatic discharge in the work environment. An explanation of the phenomenon was presented, indicating methods of generating electric charge on the surface of physical objects. The division of discharges is presented, and selected types are discussed: spark, corona, brush and propagating brush discharges. Further in the article, an analysis of real events in which electrostatic discharge occurred in industrial conditions was carried out, together with an indication of the cause of the phenomenon and protective measures. The threats that accompany the phenomenon of static electricity force the use of specific safety measures. As practice shows, negligence in this regard can cause huge losses, both from the point of view of the health and life of employees, lost and damaged property, and impact on the environment.
Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology, 2014
This paper presents the results of the minimum ignition temperature of dust layer and cloud of du... more This paper presents the results of the minimum ignition temperature of dust layer and cloud of dusts. Tests have been performed for selected dusts obtained from European and exotic wood species. Tests have been performed in accordance with EN 50281-2-1. Method A consists in determining the minimum temperature at which ignition occurs of dust and/or its decomposition on hot plate at a constant temperature. The study is used to identify the threats from industrial equipment and construction, which while working have hot surfaces, on which can create a layer of combustible dust. Method B is used for determining the minimum ignition temperature of dust cloud or other particulate solids. Method B is complementary to the method A. It is used in relation to industrial equipment, inside which dust may exist in the form of short-term cloud. The results obtained for finer dusts, i.e. 200 and 71 μm were nearly equal. The differences reaching from 10 to 30°C were observed for dust samples of mean diameter finer than 71 μm. Based on conducted research, it is possible than to order particular types of dusts according to diminishing minimum temperature of dust cloud/layer ignition as follows: oak dust ≥ eucalyptus dust > lapacho dust.
The use of non-linear devices causes unfavourable changes in the operation of the power system. F... more The use of non-linear devices causes unfavourable changes in the operation of the power system. First of all, they are a source of higher harmonics in network waveforms, which tend to increase the eddy currents. Their effect consists in raising the temperature of transformer cores. This, in turn, translates into their failure rate and fire safety, including reducing the actual value of rated power. The article describes the results of experimental studies carried out on a large scale. An analysis was performed of the quality of electric power depending on the type of network load. The results have shown that the increase in the use of non-linear receivers such as LED lighting, electronic chargers, inverters, etc. may have a tangible impact on the fire hazard of distribution transformers. Examples of calculations have been presented, which prove the necessity of taking into account the influence of higher harmonics on the reduction of the real rated power of power transformers.
Propagating brush discharges are highly energetic and pose risks to the control and indicating eq... more Propagating brush discharges are highly energetic and pose risks to the control and indicating equipment, hazardous atmosphere and human health. The nature of the PBD poses some difficulties, as one electrode, is nonconductive. Direct measurements of the voltage requires specialized equipment. Presented method uses voltage measurements on a low inductance RC circuit. PBD were also recorded with fast camera at 200 K pps. Some dependencies were observed, e.g. the energy released is usually higher for negative polarity. For chosen PVC test samples (0.2 mm thick), typical energies actually released to the atmosphere were between dozens and hundreds of mJ.
The use of non-linear devices causes unfavourable changes in the operation of the power system. F... more The use of non-linear devices causes unfavourable changes in the operation of the power system. First of all, they are a source of higher harmonics in network waveforms, which tend to increase the eddy currents. Their effect consists in raising the temperature of transformer cores. This, in turn, translates into their failure rate and fire safety, including reducing the actual value of rated power. The article describes the results of experimental studies carried out on a large scale. An analysis was performed of the quality of electric power depending on the type of network load. The results have shown that the increase in the use of non-linear receivers such as LED lighting, electronic chargers, inverters, etc. may have a tangible impact on the fire hazard of distribution transformers. Examples of calculations have been presented, which prove the necessity of taking into account the influence of higher harmonics on the reduction of the real rated power of power transformers.
In the case of natural or man-made disaster, the top priority of urban search and rescue (USAR) g... more In the case of natural or man-made disaster, the top priority of urban search and rescue (USAR) groups is to localise the victim as quickly as possible. Even minutes might play a crucial role in the victim’s survival. A number of standard operating procedures may be applied to achieve best performance. Rescue dogs are trained to search for alive victims; special inspection cameras are used, before heavy equipment is being implemented. To improve the effectiveness of USAR group operations, innovative technologies might be implemented. The most recent solution is currently designed in MOBNET project, founded by EU under the Horizon 2020 programme. The scope of the project is to combine both cellular technology and early Galileo services to localise the smartphones of potential victims. Integration tests give some promising outcomes. The following chapter looks at typical applications, real needs of public services as well as the performance of the novel system
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Papers by Szymon Ptak