Materials for Safety and Security

Author(s):  
Jozef Martinka ◽  
Janka Dibdiakova

This chapter deals with materials used in safety and security engineering. The most commonly used materials in this field include shielding materials, materials for protective suits, electrically insulating materials and materials for fire protection. The first part of the chapter describes the properties of materials used in the above applications. The second part of the chapter focuses on characteristics of materials that accurately describe their fire risk. The fire risk of a material is quantified by its resistance to ignition (determined generally by critical heat flux and ignition temperature) and by the impact of the fire on the environment. The impact of fire is usually determined by the heat release rate, toxicity of combustion products (primarily determined by carbon monoxide yield and for materials that contain nitrogen, also through the hydrogen cyanide yield) and the decrease of visibility in the area (depending on the geometry of the area and the smoke production rate).

2021 ◽  
Vol 30 (1) ◽  
pp. 5-15
Author(s):  
N. I. Konstantinova ◽  
A. V. Zuban ◽  
E. A. Poedintsev ◽  
N. V. Golov

Introduction. The use of fireproof tent fabric at children’s tent camps remains a relevant problem. It may be resolved by developing a special flammability assessment methodology and criteria applicable to materials, used as the structural framework of tents. This solution will determine the choice of fabric.Aims and purposes. Materials, currently used to make tents, include natural or synthetic fabric and various polymers, that may be a fire hazard. In case of fire, safe evacuation of people may be unfeasible, although it is particularly important for children’s seasonal tent camps designated for sports and leisure.Domestic regulatory documents, that are currently in force, contain solely general technical requirements applicable to travel tents or ensuring fire safety in the territory of children’s tent camps, but there are neither fire safety requirements applicable to tent materials, nor any methods of their assessment. Meanwhile, there were cases of fire at children’s tent camps.The purpose of this work is to establish fire safety requirements applicable to tent materials used at children’s tent camps, to develop their testing criteria and methodology.The main objectives to be accomplished in order to achieve the pre-set purpose include the analysis of effective regulatory requirements and methods used to determine the flammability of tent materials, the establishment of parameters and criteria designated for their assessment and the development of a standard testing methodology.Results and discussion. Experimental studies were carried out to assess a set of flammability-related parameters of several types of fabric and polymers used to make outer/inner tents and ground sheets. It has been determined that currently used materials are fire-hazardous; therefore, it is advisable to limit the production of tents from combustible and flammable materials whose combustion may be triggered by low-calorie ignition sources, including those that can melt or release toxic combustion products.Currently used standard methods were applied to develop modified methodologies and classification criteria needed to assess the flammability of tent materials for children’s summer camps; experimental studies were also carried out.Conclusions. A draft national standard has been developed; it implies the establishment of the flammability assessment methodology and criteria and restricts the use of tent materials, that are extremely hazardous in terms of the toxicity of their combustion products.


Author(s):  
Д.Ф. Кожевин ◽  
А.С. Поляков ◽  
Д.А. Скороходов ◽  
В.Ю. Каминский ◽  
А.Л. Стариченков

Для трубопроводов, проложенных под водой, опасными являются следующие факторы пожара: тепловое излучение при факельном горении природного газа над поверхностью моря, избыточное давление и импульс волны давления при сгорании газопаровоздушной смеси, а также расширяющиеся продукты сгорания при реализации пожара-вспышки газопаровоздушной смеси. При этом рассмотрены особенности газового конденсата и моноэтиленгликоля. Выполнена оценка пожарных рисков и составлен перечень исходных данных для их расчётов. Описана последовательность развития аварии. При построении дерева событий учтена глубина подводного размещения трубопровода. При проведении анализа риска использованы четыре сценария выхода природного газа на поверхность. Определена величина потенциального пожарного риска в определенной точке трассы трубопровода. Выполнена оценка воздействия поражающих факторов при авариях на шлангокабеле и на трубопроводе. Рассмотрены нестабильные динамические явления, сопровождающие аварию на морском трубопроводе: в начальный период воздействия ударной волны, выбросе воды на палубу судна и пожароопасного воздушного шлейфа над поверхностью моря. For pipelines laid under water, the following fire factors are dangerous: thermal radiation when natural gas flares above the sea surface, excessive pressure and pressure wave momentum when a gas-air mixture is burned, as well as expanding combustion products when a gas-air mixture is flashed. Gorenje The features of gas condensate and monoethylene glycol are considered. Fire risks were assessed and a list of initial data for their calculations was compiled. The sequence of accident development is described. When building the event tree, the depth of the underwater pipeline placement is taken into account. During the risk analysis, four scenarios of natural gas coming to the surface were used. The value of the potential fire risk at a certain point of the pipeline route is determined. An assessment of the impact of damaging factors in accidents on the hose cable and on the pipeline was performed. Unstable dynamic phenomena accompanying an accident on an offshore pipeline are considered: during the initial period of impact of a shock wave, the release of water on the ships deck and a fire-dangerous air plume above the sea surface.


2020 ◽  
Vol 128 ◽  
pp. 81-88 ◽  
Author(s):  
Paweł Kowalik ◽  
Mariusz Fabijański

The purpose of this study is to present the requirements, methodology, and results of research on the impact of biodegradable oil on plastic components used in the construction of a railway turnout. Briefly discussed are what railroad turnouts are, how they work, and what problems occur with substances used for their lubrication. They have an impact on the mechanical properties and durability of products made of polymeric materials. These types of materials absorb various kinds of chemicals, to a greater or lesser degree, and this affects their properties. For the tests, we used a universal lubrication oil with biodegradable properties, which is its most significant advantage. However, it may not cause deterioration of the turnout operation and change the properties of materials used for its construction. These types of oils require more frequent applications on cooperating components. We used the two most popular polymer materials. The first is high-density polyethylene (HDPE), used to make all kinds of rail spacers, dowels for fixing rails, sleeves, etc. The second, polyurethane (PUR) is most commonly used for rail pads of various shapes. The methodology and results of testing the impact of a lubricant (biodegradable oil) on the change of mechanical properties such as strength and hardness are presented. The tests were carried out at various temperatures; the time of exposure to oil was seven days; the results were referred to samples conditioned under standard conditions. The tests carried out on the impact of the biodegradable lubricant on polymeric materials (HDPE and PUR) showed little effect on the change of strength parameters of these materials. Celem niniejszego opracowania jest przedstawienie wymagań, metodyki oraz wyników badań oddziałania biodegradowalnego oleju na elementy z tworzyw sztucznych stosownych w budo-wie rozjazdu kolejowego. Krótko omówiono czym są rozjazdy kolejowe i jak działają oraz jakie występują problemy z substancjami używanymi do ich smarowania, które nie pozostają bez wpływu na właściwości mechaniczne i trwałość wyrobów z materiałów polimerowych. Materiały tego typu wchłaniają różnego rodzaju substancje chemiczne w większym lub mniejszym stopniu, a to ma wpływ na ich właściwości. Do badań został wykorzystany uniwersalny olej do smarowania o biodegradowalnych właściwościach, co jest jego największą zaletą. Jednak nie może on powodować pogorszenia pracy rozjazdu oraz zmieniać właściwości materiałów użytych do jego budowy. Tego typu oleje wymagają częstszego aplikowania na elementy współpracujące ze sobą. W pracy wykorzystano dwa najbardziej popularne materiały polimerowe. Pierw-szy to polietylen o dużej gęstości (HDPE), z którego wykonuje się wszelkiego rodzaju przekładki podszynowe, dyble do mocowania szyn, tuleje, itp. Drugi to poliuretan (PUR) stosowany najczęściej na przekładki podszynowe o różnym kształcie. Zaprezentowano metodykę i wyniki ba-dań oddziaływania środka smarnego (biodegradowalnego oleju) na zmianę właściwości mechanicznych takich jak wytrzymałość oraz twardość. Badania zostały przeprowadzone w różnych temperaturach, a czas ekspozycji na olej wynosił 7 dób, wyniki odniesiono do próbek klimatyzowanych w standardowych warunkach. Przeprowadzone badania oddziaływania biodegradowalnego środka smarnego na tworzywa polimerowe (HDPE i PUR), wykazały niewielki wpływ na zmianę parametrów wytrzymałościowych tych materiałów.


2013 ◽  
Vol 19 (4) ◽  
pp. 561-572 ◽  
Author(s):  
Marzena Półka ◽  
Jerzy Gałaj ◽  
Zbignev Karpovič

In order to investigate the impact of some inorganic additive flame retardants on the selected fire properties of the materials based on polyester resin Polimal 1033 APy, small-scale fire testing techniques have been used. Seven samples have been studied: unmodified PES, PES modified with MoO3 (7, 14 and 21 wt%) and PES modified with Sb2O3 (7, 14 and 21 wt%). The following flammable properties of materials have been determined: the heat of combustion (HOC), the ignition temperature of volatile thermal decomposition products (Tig), self-ignition temperature and oxygen index. A cone calorimeter method has been used for determining heat release rate (HRR), mass loss, specific extinction area (SEA) and other combustion parameters. The toxicological analysis of combustion products has been conducted. Based on the obtained results, the following conclusions have been made: (1) MoO3 and Sb2O3 added to the studied material change its flammable properties and fire parameters. It can be indicated by higher HOC, higher Tig and self-ignition temperature, as well as by lower HRR and SEA. Modified materials become safer in terms of fire hazard. (2) A significant reduction in HRRmax of approx. 40% in the content of 7 wt% has been observed. The lowest HRRmaxof approximately 300 kW/m2 and 450 kW/m2 have been obtained for 21 wt% in a range of 200–600 s at 30 kW/m2 and 100–400 s at 50 kW/m2 respectively. Except for a sample containing 7 wt% of Sb2O3, a clear local reduction in HRR (from 50 to 150 kW/m2), in case of all modified samples has been noticed. (3) Sb2O3 has a greater impact on the thermostability of the studied materials compared to MoO3 in all cases of heat flux density and additive concentrations. The effectiveness of Sb2O3, as a flame retardant is the most evident at 21 wt%.


1997 ◽  
Vol 161 ◽  
pp. 179-187
Author(s):  
Clifford N. Matthews ◽  
Rose A. Pesce-Rodriguez ◽  
Shirley A. Liebman

AbstractHydrogen cyanide polymers – heterogeneous solids ranging in color from yellow to orange to brown to black – may be among the organic macromolecules most readily formed within the Solar System. The non-volatile black crust of comet Halley, for example, as well as the extensive orangebrown streaks in the atmosphere of Jupiter, might consist largely of such polymers synthesized from HCN formed by photolysis of methane and ammonia, the color observed depending on the concentration of HCN involved. Laboratory studies of these ubiquitous compounds point to the presence of polyamidine structures synthesized directly from hydrogen cyanide. These would be converted by water to polypeptides which can be further hydrolyzed to α-amino acids. Black polymers and multimers with conjugated ladder structures derived from HCN could also be formed and might well be the source of the many nitrogen heterocycles, adenine included, observed after pyrolysis. The dark brown color arising from the impacts of comet P/Shoemaker-Levy 9 on Jupiter might therefore be mainly caused by the presence of HCN polymers, whether originally present, deposited by the impactor or synthesized directly from HCN. Spectroscopic detection of these predicted macromolecules and their hydrolytic and pyrolytic by-products would strengthen significantly the hypothesis that cyanide polymerization is a preferred pathway for prebiotic and extraterrestrial chemistry.


Author(s):  
Юрий Зубарев ◽  
Yuriy Zubarev ◽  
Александр Приемышев ◽  
Alexsandr Priyomyshev

Tool materials used for polymeric composite blank machining, kinds of tool material wear arising at machining these blanks, and also the impact of technological parameters upon tool wear are considered. The obtained results allow estimating the potentialities of physical models at polymeric composite blanks cutting.


2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Caroline Ward ◽  
Lindsay C. Stringer ◽  
Eleanor Warren-Thomas ◽  
Fahmuddin Agus ◽  
Merry Crowson ◽  
...  

AbstractThe Indonesian government committed to restoring over 2 million ha of degraded peatland by the end of 2020, mainly to reduce peat fires and greenhouse gas emissions. Although it is unlikely the government will meet this target, restoration projects are still underway. One restoration strategy involves blocking peatland drainage canals, but the consequences of this for smallholder farmers whose livelihoods are dependent on agriculture are unclear. This paper investigates perceived impacts of canal blocks on smallholder farmers and identifies factors that affect their willingness to accept canal blocks on their land. We use data from 181 household questionnaires collected in 2018 across three villages in Jambi province, Sumatra. We found that the majority of respondents would accept canal blocks on their farms, perceiving that the blocks would have no impact on yields or farm access, and would decrease fire risk. Respondents who would not accept blocks on their farms were more likely to use canals to access their farms and perceive that canal blocks would decrease yields. The majority of farmers unwilling to accept canal blocks did not change their mind when provided with an option of a block that would allow boat travel. Our results improve understanding of why some smallholders may be unwilling to engage with peatland restoration. Further research is needed to understand the impact of canal blocks on smallholders’ yields. Engaging with stakeholders from the outset to understand farmers’ concerns, and perceptions is key if the government is to succeed in meeting its peatland restoration target and to ensure that the costs and benefits of restoration are evenly shared between local stakeholders and other actors.


Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 519
Author(s):  
Vitalii Bezgin ◽  
Agata Dudek ◽  
Adam Gnatowski

This paper proposes and presents the chemical modification of linear hydroxyethers (LHE) with different molecular weights (380, 640, and 1830 g/mol) with the addition of three types of rubbers (polysulfide rubber (PSR), polychloroprene rubber (PCR), and styrene-butadiene rubber (SBR)). The main purpose of choosing this type of modification and the materials used was the possibility to use it in industrial settings. The modification process was conducted for a very wide range of modifier additions (rubber) per 100 g LHE. The materials obtained in the study were subjected to strength tests in order to determine the effect of the modification on functional properties. Mechanical properties of the modified materials were improved after the application of the modifier (rubber) to polyhydroxyether (up to certain modifier content). The most favorable changes in the tested materials were registered in the modification of LHE-1830 with PSR. In the case of LHE-380 and LHE-640 modified in cyclohexanol (CH) and chloroform (CF) solutions, an increase in the values of the tested properties was also obtained, but to a lesser extent than for LHE-1830. The largest changes were registered for LHE-1830 with PSR in CH solution: from 12.1 to 15.3 MPa for compressive strength tests, from 0.8 to 1.5 MPa for tensile testing, from 0.8 to 14.7 MPa for shear strength, and from 1% to 6.5% for the maximum elongation. The analysis of the available literature showed that the modification proposed by the authors has not yet been presented in any previous scientific paper.


Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1427
Author(s):  
Katarzyna Solarska-Ściuk ◽  
Kinga Adach ◽  
Sylwia Cyboran-Mikołajczyk ◽  
Dorota Bonarska-Kujawa ◽  
Agnieszka Rusak ◽  
...  

Silicon dioxide, in the form of nanoparticles, possesses unique physicochemical properties (size, shape, and a large surface to volume ratio). Therefore, it is one of the most promising materials used in biomedicine. In this paper, we compare the biological effects of both mesoporous silica nanoparticles extracted from Urtica dioica L. and pyrogenic material. Both SEM and TEM investigations confirmed the size range of tested nanoparticles was between 6 and 20 nanometers and their amorphous structure. The cytotoxic activity of the compounds and intracellular ROS were determined in relation to cells HMEC-1 and erythrocytes. The cytotoxic effects of SiO2 NPs were determined after exposure to different concentrations and three periods of incubation. The same effects for endothelial cells were tested under the same range of concentrations but after 2 and 24 h of exposure to erythrocytes. The cell viability was measured using spectrophotometric and fluorimetric assays, and the impact of the nanoparticles on the level of intracellular ROS. The obtained results indicated that bioSiO2 NPs, present higher toxicity than pyrogenic NPs and have a higher influence on ROS production. Mesoporous silica nanoparticles show good hemocompatibility but after a 24 h incubation of erythrocytes with silica, the increase in hemolysis process, the decrease in osmotic resistance of red blood cells, and shape of erythrocytes changed were observed.


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