Preparation, Properties and Application of Gel Materials for Coal Gangue Control

In order to solve the problem of the spontaneous combustion of coal gangue, a coal gangue fire-extinguishing material of gel–foam was developed. The foaming agent was screened by the Waring blender method with varying foam amounts, and the superabsorbent foam stabilizer was synthesized by free radical polymerization. Moreover, the gel–foam was used in a spontaneous combustion of coal gangue mountain field practice. The results showed that when the mass fraction of sodium dodecyl sulfonate and coconut oil amide propyl betaine was 0.6% and 4:6, the foaming amount was as high as 1500 mL. When the mass ratio of chitosan to acrylic acid was 1:6, the neutralization degree was 80%, the cross-linking agent was 0.8%, and the initiator was 0.01%, the water absorption of the synthesized superabsorbent foam stabilizer reached 476 mL/g. The synthesized gel–foam was tested in a spontaneous combustion coal gangue hill in a certain area, and no reburning sign was found within one month.

The Book about Igor Sikorky

Obraztsov, P. A. Igor Sikorsky: four wars and two homelands of the famous aircraft designer. Moscow, Molodaya gvardiya publishing house, 2021, 239 [1] p.: ill. (Series of biographies: The life of remarkable people; issue 1875). ISBN 978-5-235-04435-7.Igor Sikorsky created a family of the world’s best helicopters, which transported marines and doctors during almost all wars of the 20th and 21st centuries, mail and fire extinguishing equipment, oversized cargo, ordinary passengers and even US presidents. In Russia, this Russian-American genius created the world’s first huge multi-engine aircrafts Russky Vityaz [Russian Knight] and Ilya Muromets, and in America, where he was respectfully called Mister Helicopter, extraordinary seaplanes that crossed the Atlantic and Pacific Oceans even before World War II.

Adaptation of Fire-Fighting Systems to Localization of Fires in the Premises: Review

Fire protection is a basic safety issue for all categories of buildings. The criteria for effective fire suppression and the characteristics of extinguishing systems in insulated areas depend on a combination of factors. The main influences include the type of combustible material, ambient temperature, type of spray extinguisher, air inflow and outflow conditions, and space geometry. This article analyzes the most widely used fire-extinguishing technologies in different locations. The main aspects of using the pulsed delivery technology of extinguishing liquid are considered. Based on the analysis of publications from the last decade, it is possible to develop intelligent systems for recording fires and extinguishing fires in the premises.

Landslide Trail Extraction Using Fire Extinguishing Model

Landslide trails are important elements of landslide inventory maps, providing valuable information for landslide risk and hazard assessment. Compared with traditional manual mapping, skeletonization methods offer a more cost-efficient way to map landslide trails, by automatically generating centerlines from landslide polygons. However, a challenge to existing skeletonization methods is that expert knowledge and manual intervention are required to obtain a branchless skeleton, which limits the applicability of these methods. To address this problem, a new workflow for landslide trail extraction (LTE) is proposed in this study. To avoid generating redundant branches and to improve the degree of automation, two endpoints, i.e., the crown point and the toe point, of the trail were determined first, with reference to the digital elevation model. Thus, a fire extinguishing model (FEM) is proposed to generate skeletons without redundant branches. Finally, the effectiveness of the proposed method is verified, by extracting landslide trails from landslide polygons of various shapes and sizes, in two study areas. Experimental results show that, compared with the traditional grassfire model-based skeletonization method, the proposed FEM is capable of obtaining landslide trails without spurious branches. More importantly, compared with the baseline method in our previous work, the proposed LTE workflow can avoid problems including incompleteness, low centrality, and direction errors. This method requires no parameter tuning and yields excellent performance, and is thus highly valuable for practical landslide mapping.

A Study on the Durability of Fire Hoses of Fire Hydrants

Although the number of fires has not changed considerably in recent times, property damage and casualties due to fires are increasing every year. Maintaining the performance of fire-fighting facilities installed in buildings has been emphasized for maximizing human safety and minimizing property damage caused by fires. As a result, since 2017, the maintenance of fire extinguishers throughout their service life, has been mandated. In case of a fire, initial fire extinguishing and fire spreading prevention are crucial. There have been no available measures for the maintenance and verification of indoor fire hydrants and outdoor fire hydrant hoses used for extinguishing fires and preventing combustion expansion. This study was therefore intended to present measures for ascertaining the service life of these fire extinguishers, by evaluating their firefighting abilities through sample analysis and case analysis of the fire hoses. Research shows that the degradation of performance of the fire hoses becomes evident between 9 and 10 years, so that 10 years of service life is considered appropriate for the fire hoses.

Comparison of Domestic and International Technical Standards: Study on Improvement of Quality Control of Halogenated Fire Extinguishing Agents

Recently, the National Fire Protection Association (NFPA) announced the revised standards for halogen compound fire extinguishing facilities (NFPA 2001). Characteristically, it is strengthening the quality control standards for halogenated fire extinguishing agents, by presenting specific standards regarding the effects of not only their main ingredient, but also their additional ingredients on the human body. However, in Korea, halogen compound fire extinguishing agents used for firefighting purposes are managed by designating “purity” as the sole criteria for inspection. Considering that halogen compounds utilized for other purposes in Korea are undergoing quality control through various inspections for the safety of humans and the environment, it is evident that a higher level of quality control is required for halogen compounds used for firefighting purposes. Therefore, we would like to suggest a specific improvement plan to enhance safety while using halogenated fire extinguishing agents, through the comparative analysis of inspection criteria, and acceptance standards of corresponding domestic and foreign standards.

Experimental Study on Prevention of Thermal Runaway Propagation in Pouch-type Lithium-ion Batteries

In this study, thermal runaway propagation characteristics and measures to prevent this phenomenon were analyzed by applying abnormal thermal conditions to pouch-type lithium-ion batteries. Experiments were conducted in a 1.5 m × 1.5 m × 1.5 m experimental chamber. During the experiment, pouch-type lithium-ion batteries were grouped according to capacity, quantity, and the use of fire extinguishing agents. Experiments showed that when thermal runaway occurred in a cell, it propagated to the adjacent cell after a certain period. The surface temperature of the cell where thermal runaway first occurred was above 200 ℃, and thermal runaway propagated via heat transfer to the adjacent cell. In the case of thermal runaway, when a fire extinguishing agent was applied, the propagation of thermal runaway to adjacent cells was prevented due to a cooling effect. However, at a cell capacity of 100 Ah, flame generation persisted and thermal runaway was unavoidable. To prevent thermal runaway propagation, it is necessary to select an extinguishing agent that exerts a cooling effect. The capacity and structure of the model unit should be considered when installing fire extinguishing systems.