Search

Flammability and smoke generation of glass-fiber-reinforced polyester laminates (GFRPs) modified with L-arginine phosphate (ArgPA) have been investigated. The composition, structure, and thermal degradation processes of ArgPA were assessed by the elemental, FTIR, and thermogravimetric analyses. Flammability and smoke emission of GFRPs varying by different amounts (5–15 wt.%) of bio-based flame retardant (FR) prepared via hand lay-up method were assessed in terms of the limiting oxygen index (LOI) and smoke density tests. It was observed that the addition of ArgPA results in the formation of a charred layer with visible bubbles. The LOI of GFRP with 15 wt.% of ArgPA increased from 20.73 V/V % (non-modified GFRP) to 24.55 V/V %, and the material classification was improved from combustible to self-extinguishing. FRs usually increase the specific optical density of smoke, which was also observed for ArgPA-modified GFRPs. However, the specific optical density of smoke at the 4th minute of measurement (Ds(4)) obtained for ArgPA-modified GFRPs was lower than for GFRPs modified with commercially used APP. TG/FTIR studies of resin modified with ArgPA revealed the presence of phosphorus compounds and non-combustible gases in the decomposition products. Results demonstrate the potential of ArgPA as an effective, bio-based FR for the enhancement of GFRP fire safety. [ABSTRACT FROM AUTHOR]

Military ammunition and derivative materials that have reached the end of their service life are classified as hazardous waste due to the presence of explosives, necessitating proper decommissioning. Valorization of such materials through the reuse of energetic components offers a sustainable alternative, aligning with circular economy principles. This study aims to assess the environmental impact of civilian emulsion explosives (EEs) formulated with nitrocellulose powder derived from recycled ammunition, comparing these findings to traditional EEs and EEs containing standard nitrocellulose powder. The Life Cycle Analysis (LCA) was performed using the CML Baseline v3.07 methodology combined with the Ecoinvent 3.8 database, utilizing inventory data obtained from Polish sources. The results indicate that incorporating nitrocellulose powder into conventional EEs increases the overall environmental impact by 4.5%, while utilizing recycled nitrocellulose powder reduces the impact by 4.99%. This highlights the environmental benefits of recycling energetic materials for use in civilian applications, as it not only reduces hazardous waste and reliance on virgin materials but also supports the principles of the circular economy. By closing the loop on material use, this approach promotes environmental sustainability and resource efficiency, aligning with broader goals of sustainable development. [ABSTRACT FROM AUTHOR]

Lightweight concrete exhibits many advantages over traditional concrete such as lower density and thermal conductivity and an easier, cheaper, less energy-consuming manufacturing process. In order to extend its applications, there is a need to study its behavior in fire situations. Due to that, the aim of this study was to assess the fire resistance of foam concrete, depending on its thickness and the foaming process applied. Fire resistance was assessed according to EN 1363-1. The results indicate the usefulness of foam concrete in terms of isolating fire temperatures for discontinuous partition filling that are consequently a real alternative to dedicated solutions in the field of passive fire protection. The density of foam concrete was shown to have a large effect on the ability to insulate fire temperatures with a standard material preparation process. It was also noted that changing the method to continuous foam feeding may result in the achievement of similar values while maintaining foam concrete low density. [ABSTRACT FROM AUTHOR]

For many years, efforts have been made to reduce the flammability of unsaturated polyester resins (UPRs), which are often used in the rail, shipbuilding, and construction industries. Without modification, they often fail to meet fire safety standards. Despite a rich history of flame retardants (FRs) applied to UPRs, researchers seek new solutions that will provide lower flammability and smoke density, as well as attaining a lower environmental impact from the composites. The objective of the study is to highlight the most important recent research on promising nano FRs in order to promote their further development. Mechanisms of action of several groups of nano FRs, such as clay-based, carbon-based, transition metal compounds, layered double hydroxides, polyhedral oligomeric silsesquioxanes, and others, including bio-based, have been studied. Particular emphasis has been laid on nano FRs applied to UPRs, and their influences on thermal stability, flammability, and mechanical properties. Moreover, the environmental impact and toxicity of nano FRs have been discussed. Results have proved that nano FRs applied at low loadings may significantly improve thermal stability, with a simultaneous increase or only a slight decrease in mechanical properties. However, attention on related environmental issues has highlighted the necessity of carefully selecting novel nano FRs. [ABSTRACT FROM AUTHOR]

Lycopodium (L.) clavatum powder, due to its uniform particle size distribution and low equilibrium moisture content, is often used as a reference material and a calibration benchmark for dust combustion and dust explosion studies. The aim of the study was to determine its fire and explosion parameters, compare them to values obtained in the previous literature findings, and assess the appropriateness of using lycopodium powder as a reference material. The research included the determination of minimum ignition temperatures of dust layer and dust clouds, spontaneous ignition behavior, and explosion characteristics of dust clouds including maximum explosion pressure, maximum rate of explosion pressure rise, and the lower explosion limit of the air/dust mixture. The results reveal that the maximum equipment temperature used with lycopodium dust should not exceed 215 °C for dust thickness up to 5 mm. In order to eliminate the risk of lycopodium dust ignition, the temperature of the equipment surfaces that can come into contact with the dust cloud should not exceed 300 °C. In order to prevent explosions, the concentration of lycopodium dust in air should not be greater than 15 g/m3. Based on the obtained results, it can be seen that lycopodium fire and explosion parameters vary slightly, and its usage as a benchmark is considered legitimate. [ABSTRACT FROM AUTHOR]

Sewage sludge may pose a fire risk. The safe storage of biomass waste is a challenge due to self-heating processes. This study aims to assess the propensity to spontaneously combust of sewage sludge in order to determine safe storage and transport conditions. The evaluation of spontaneous ignition hazard was assessed according to EN 15188, by the determination of the self-ignition temperature. Certain parameters assumed to affect the inclination of sewage sludge to self-ignite, including the moisture content, bulk density, elemental composition, and particle size, were discussed. The results showed the risk of self-ignition during the storage and transport of sludge dust and pellets. The usage of the smallest basket volume resulted in the highest self-ignition temperatures, which were 186 °C and 160 °C for sludge pellets and dust, respectively. The comparison of the two forms of thermally dry sludge showed, that despite sludge pellets being easier to store and handle issues, the more favorable conditions for the management in terms of fire risk is sludge dust. Its temperatures for safe storage are slightly higher. The results highlighted that future research should focus on the hazards of silo fires and explosions in terms of silo fire prevention and management. [ABSTRACT FROM AUTHOR]

This paper presents the results of detonation and explosion characteristics for ammonium nitrate, aluminium, and aluminium-magnesium alloy powder mixtures. The following parameters were determined: detonation velocities, blast waves overpressure and their specific impulses. The emission of radiation was recorded, and the history of temperature of the detonation products cloud was established. It was shown that addition of aluminium-magnesium alloy powder increases blast waves' characteristics. Moreover, it increases the time of the afterburning reaction after detonation and increases the temperature of detonation products. [ABSTRACT FROM AUTHOR]

This paper presents the results of detonation parameters for ammonium nitrate-polyhydroxy alcohol mixtures and ternary explosive compositions modified by flaked aluminium. The detonation velocities, overpressures of blast waves and their specific impulses were determined. It was shown that the viscosity of liquid fuels is the leading property that determines the detonation parameters of the tested compositions. [ABSTRACT FROM AUTHOR]

Soil information is the basis for the site-specific management of soils. The study aimed to digitize soil information and classify it into soil mapping units (SMUs) using geostatistics. The study area was grouped into 12 SMUs, or management zones. The pH of the soils ranged from 7.3 in SMU2 to 8.6 in SMU5. Most SMUs exhibited low total nitrogen (TN) that could be attributed to very low soil organic carbon (SOC) in the soils. Available phosphorus (AvP) was very low in all the mapping units. The exchangeable K varied between 0.12 cmol(+) kg−1 (SMU7) and 0.95 cmol(+) kg−1 (SMU10). SMU12 was identified as marginally sodic and at a high risk of developing severe alkalinity unless possible management measures are implemented. Our findings show that a lack of soil information causes an imbalance between soil requirements and external nutrient inputs, negatively affecting crop production. Therefore, high-resolution digital soil information can assist the site-specific application of soil nutrients and amendments based on spatial variability in line with soil requirements. [ABSTRACT FROM AUTHOR]

Environmental factors are the major constraints in sustainable agriculture. WRKY proteins are a large family of transcription factors (TFs) that regulate various developmental processes and stress responses in plants, including cotton. On the basis of Gossypium raimondii genome sequencing, WRKY TFs have been identified in cotton and characterized for their functions in abiotic stress responses. WRKY members of cotton play a significant role in the regulation of abiotic stresses, i.e., drought, salt, and extreme temperatures. These TFs either activate or repress various signaling pathways such as abscisic acid, jasmonic acid, salicylic acid, mitogen-activated protein kinases (MAPK), and the scavenging of reactive oxygen species. WRKY-associated genes in cotton have been genetically engineered in Arabidopsis, Nicotiana, and Gossypium successfully, which subsequently enhanced tolerance in corresponding plants against abiotic stresses. Although a few review reports are available for WRKY TFs, there is no critical report available on the WRKY TFs of cotton. Hereby, the role of cotton WRKY TFs in environmental stress responses is studied to enhance the understanding of abiotic stress response and further improve in cotton plants. [ABSTRACT FROM AUTHOR]

This paper presents a review of flame retardants used for glass/polyester laminates. It concerns flame retardants withdrawn from use such as compounds containing halogen atoms and flame retardants currently used in the industry, such as inorganic hydroxides, phosphorus and nitrogen-containing compounds, antimony, and boron compounds, as well as tin–zinc compounds. Attention is also drawn to the use of nanoclays and the production of nanocomposites, intumescent flame retardant systems, and mats, as well as polyhedral oligomeric silsesquioxanes. The paper discusses the action mechanism of particular flame retardants and presents their advantages and disadvantages. [ABSTRACT FROM AUTHOR]

Knowledge of the drying properties of tobacco in high temperatures above 100 °C and its dust are crucial in the design of dryers, both in the optimization of the superheated-steam-drying process and in the correct selection of innovative explosion protection and mitigation systems. In this study, tobacco properties were determined and incorporated into the proposed model of an expanding superheated steam flash dryer. The results obtained from the proposed model were validated by using experimental data yielded during test runs of an industrial scale of a closed-loop expansion dryer on lamina cut tobacco. Moreover, the explosion and fire properties of tobacco dust before and after the superheated steam-drying process at 160, 170, 180, and 190 °C were experimentally investigated, using a 20 L spherical explosion chamber, a hot plate apparatus, a Hartmann tube apparatus, and a Godbert–Greenwald furnace apparatus. The results indicate that the higher the drying temperature, the more likely the ignition of the dust tobacco cloud, the faster the explosion flame propagation, and the greater the explosion severity. Tobacco dust is of weak explosion class. Dust obtained by drying with superheated steam at 190 °C is characterized by the highest value of explosion index amounting to 109 ± 14 m·bar·s−1, the highest explosion pressure rate (405 ± 32 bar/s), and the maximum explosion pressure (6.7 ± 0.3 bar). The prevention of tobacco-dust accumulation and its removal from the outer surfaces of machinery and equipment used in the superheated steam-drying process are highly desirable. [ABSTRACT FROM AUTHOR]