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16 pages, 4079 KiB

Open AccessArticle

Modernization of Fire Vehicles with New Technologies and Chemicals

by Cagri Un and Kadir Aydın

Vehicles 2023, 5(2), 682-697; https://doi.org/10.3390/vehicles5020037 - 4 Jun 2023

Cited by 3 | Viewed by 4610

Fire is a stable exothermic chain reaction of flammable materials brought together with oxygen or other oxidizing substances under certain conditions, occurring uncontrollably. Fire vehicles interfere with many types of fire, such as wildfires, factory fires, building fires, etc. During this intervention, fire vehicles generally use water or foam. In this study, new effective fire suppression applications are investigated. Thermal camera applications in fire trucks and also new extinguishing agents—boron-based chemicals—were tested in forest fire simulations. In these experiments, it was observed that the thermal camera detected the fire as soon as it occurred. It seemed appropriate to use thermal cameras for all types of fire vehicles (foam trucks, water tankers, rescue trucks, etc.). It was seen that the thermal camera application could detect and monitor the fire during the fire-extinguishing work of the firefighters. The boron-based fire suppressant had a better extinguishing and cooling effect than water in the experiments. Compared to the water used as a traditional method, the liquid boron-based extinguisher provided 22% faster—while the solid boron-based extinguisher provided 42% faster—suppression and cooling. With three separate experiments, it is predicted that thermal camera applications and the use of boron-based extinguishers in fire vehicles can lead to an effective and positive transformation in the coming years. Full article

(This article belongs to the Special Issue Vehicle Design Processes)

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17 pages, 9195 KiB

Open AccessArticle

Effects of Injection Molding Process Parameters on the Chemical Foaming Behavior of Polypropylene and Polystyrene

by Chen-Yuan Chung, Shyh-Shin Hwang, Shia-Chung Chen and Ming-Chien Lai

Polymers 2021, 13(14), 2331; https://doi.org/10.3390/polym13142331 - 16 Jul 2021

Cited by 28 | Viewed by 5586

Abstract

In the present study, semi-crystalline polypropylene (PP) and amorphous polystyrene (PS) were adopted as matrix materials. After the exothermic foaming agent azodicarbonamide was added, injection molding was implemented to create samples. The mold flow analysis program Moldex3D was then applied to verify the short-shot results. Three process parameters were adopted, namely injection speed, melt temperature, and mold temperature; three levels were set for each factor in the one-factor-at-a-time experimental design. The macroscopic effects of the factors on the weight, specific weight, and expansion ratios of the samples were investigated to determine foaming efficiency, and their microscopic effects on cell density and diameter were examined using a scanning electron microscope. The process parameters for the exothermic foaming agent were optimized accordingly. Finally, the expansion ratios of the two matrix materials in the optimal process parameter settings were compared. After the experimental database was created, the foaming module of the chemical blowing agents was established by Moldex3D Company. The results indicated that semi-crystalline materials foamed less due to their crystallinity. PP exhibits the highest expansion ratio at low injection speed, a high melt temperature, and a low mold temperature, whereas PS exhibits the highest expansion ratio at high injection speed, a moderate melt temperature, and a low mold temperature. Full article

(This article belongs to the Special Issue Recent Developments in Polymer Foaming Processes)

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17 pages, 4248 KiB

Open AccessArticle

Characterization of Different Chemical Blowing Agents and Their Applicability to Produce Poly(Lactic Acid) Foams by Extrusion

by Ákos Kmetty, Katalin Litauszki and Dániel Réti

Appl. Sci. 2018, 8(10), 1960; https://doi.org/10.3390/app8101960 - 17 Oct 2018

Cited by 52 | Viewed by 9093

Abstract

This study presents the applicability of different types (exothermic and endothermic) of chemical blowing agents (CBAs) in the case of poly(lactic acid) (PLA). The amount of foaming agent is a fixed 2 wt%. We used a twin-screw extruder and added the individual components in the form of dry mixture through the hopper of the extruder. We characterized the PLA matrix and the chemical blowing agents with different testing methods. In case of the produced foams we carried out morphological and mechanical tests and used scanning electron microscopy to examine cell structure. We showed that PLA can be successfully foamed with the use of chemical blowing agents. The best results were achieved with an exothermic CBA and with PLA type 8052D. The cell population density of PLA foams produced this way was 4.82 × 10⁵ cells/cm³, their expansion was 2.36, their density 0.53 g/cm³ and their void fraction was 57.61%. Full article

(This article belongs to the Section Materials Science and Engineering)

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