基于BIMFire-YOLO的消防监控图像识别方法

在传统条件下,通常存在着火灾现场情况多变,建筑物内构造复杂等问题,使得消防监控系统难以通过现有方法精准检测识别火灾第一现场和所处室内环境。为了优化检测算法在复杂场景下的应用效果,文中提出BIMFire-YOLO检测方法,在以往YOLOv3主干网络中增加了新的卷积方式,在扩大了卷积感受野范围的同时,也保证了输出特征的不变性,对小火焰和烟雾等目标的检测能力有所提升。通过引入新的损失函数,降低了火灾发生的目标漏检率,融合BIM技术不仅提升了定位精度也实现了自动识别视频和图像中失火的场景。该算法不仅提高了检测效率,也实现了火灾的信息共享与管理的统一,在实际医院场景下的综合识别精度达到了45.6%,检测速度和精度均优于其他同类方法。

基于FireNet的古建筑火灾检测方法研究及改进

针对古建筑火灾检测需要快速、准确及实时的需求,建立了一个专门用于古建筑火灾检测的数据集,用于古建筑火灾检测的深度学习研究。利用CBAM注意力机制模块,结合多尺度特征融合,对FireNet网络进行改进,提出适用于古建筑火灾检测的轻量级FireNet-AMF网络,在FireNet数据集和本文构建的古建筑火灾检测数据集上验证了FireNet-AMF网络的火灾检测能力。与改进前的网络相比,FireNet-AMF网络在FireNet数据集上对火灾识别的准确率达到了95.08%,与原网络相比提高了1.17%,在本文构建的古建筑火灾检测数据集上的准确率达到了95.62%,比原网络提高了1.62%。该网络在保证轻量级的同时也保证了在古建筑火灾检测中较高的检测精度。

Enhancing Fire Safety in Commercial Vehicles: Assessing the Efficacy and Advantages of Exploding Fire Extinguishing Balls

Fire incidents in commercial vehicles pose significant risks to passengers, drivers, and cargo. Traditional fire extinguishing systems, while effective, may have limitations in terms of response time, coverage, and human intervention [1]. This study investigates the efficacy of a novel fire suppression technology—the Exploding Fire Extinguishing Ball (EFEB) —as an alternative and complementary fire safety solution for commercial vehicles. The research employs a multidisciplinary approach, encompassing engineering, materials science, fire safety, and human factors analysis. A systematic literature review establishes a comprehensive understanding of existing fire suppression technologies, including EFEBs. Subsequently, this study analyzes the unique features of EFEBs, such as automatic activation, as well as manual activation upon exposure to fire, and their potential to provide rapid, localized, and autonomous fire suppression. The study presents original experimental investigations to assess the performance and effectiveness of EFEBs in various fire scenarios representative of commercial vehicles. Experiments include controlled fires in confined spaces and dynamic simulations to emulate real-world fire incidents. Data on activation times, extinguishing capability, and coverage area are collected and analyzed to compare the efficacy of EFEBs with traditional fire extinguishing methods. Furthermore, this research shows the practical aspects of implementing EFEBs in commercial vehicles. A feasibility study examines the integration challenges, cost-benefit analysis, and potential regulatory implications. The study also addresses the impact of EFEBs on vehicle weight, stability, and overall safety. Human factors and user acceptance are crucial elements in adopting new safety technologies. Therefore, this research utilizes an experimental design to assess the performance and effectiveness of EFEBs in various fire scenarios representative of commercial vehicles. This dissertation presents original controlled experiments to emulate real-world fire incidents, including controlled fires in confined spaces and dynamic simulations. The experimental approach ensures rigorous evaluation and objective insights into EFEBs’ potential as an autonomous fire suppression system for commercial vehicles. This includes the perspectives of drivers, passengers, fleet operators, insurance agencies, and regulatory bodies. Factors influencing trust, perceived safety, and willingness to adopt EFEBs are analyzed to provide insights into the successful integration of this technology. The findings of this research will contribute to the knowledge of fire safety technology and expand the understanding of the applicability of EFEBs in commercial vehicles.

Performance Analysis of Support Vector Machine (SVM) on Challenging Datasets for Forest Fire Detection

This article delves into the analysis of performance and utilization of Support Vector Machines (SVMs) for the critical task of forest fire detection using image datasets. With the increasing threat of forest fires to ecosystems and human settlements, the need for rapid and accurate detection systems is of utmost importance. SVMs, renowned for their strong classification capabilities, exhibit proficiency in recognizing patterns associated with fire within images. By training on labeled data, SVMs acquire the ability to identify distinctive attributes associated with fire, such as flames, smoke, or alterations in the visual characteristics of the forest area. The document thoroughly examines the use of SVMs, covering crucial elements like data preprocessing, feature extraction, and model training. It rigorously evaluates parameters such as accuracy, efficiency, and practical applicability. The knowledge gained from this study aids in the development of efficient forest fire detection systems, enabling prompt responses and improving disaster management. Moreover, the correlation between SVM accuracy and the difficulties presented by high-dimensional datasets is carefully investigated, demonstrated through a revealing case study. The relationship between accuracy scores and the different resolutions used for resizing the training datasets has also been discussed in this article. These comprehensive studies result in a definitive overview of the difficulties faced and the potential sectors requiring further improvement and focus.

Lightning in a Forest (Wild) Fire: Mechanism at the Molecular Level

The mechanism of lightning that ignites a forest fire and the lightning that occurs above a forest fire are explained at the molecular level. It is based on two phenomena, namely, internal charge separation inside the atmospheric cloud particles and the existence of a layer of positively charged hydrogen atoms sticking out of the surface of the liquid layer of water on the surface of rimers. Strong turbulence-driven collisions of the ice particles and water droplets with the rimers give rise to breakups of the ice particles and water droplets into positively and negatively charged fragments leading to charge separation. Hot weather in a forest contributes to the updraft of hot and humid air, which follows the same physical/chemical processes of normal lightning proposed and explained recently[1]. Lightning would have a high probability of lighting up and burning the dry biological materials in the ground of the forest, leading to a forest (wild) fire. The burning of trees and other plants would release a lot of heat and moisture together with a lot of smoke particles (aerosols) becoming a strong updraft. The condition for creating lightning is again satisfied which would result in further lightning high above the forest wild fire.

基于改进FireNet的轻型火灾实时检测方法

针对火灾检测精确不高,时间长等问题。设计了基于改进FireNet的轻型火灾实时检测方法,通过获取视频图像数据,网络模型进行火灾分析和识别;首先,在FireNet特征提取阶段使用多尺度卷积网络并引入通道注意力机制,以提高回归精度。其次,对全连接层的神经元个数进行压缩优化,减少计算耗时。实验表明,改进的FireNet算法模型检测精度达到96.43%,模型存储空间0.96MB,检测帧率37。相比标准算法精度提高2.5%,存储空间压缩85%,检测帧率提升35%。

Modeling and Simulation Study on Reverse Swirl of Secondary Air in Large Tangentially Fired Boiler

Based on the porosity method and the improved non uniform QUICK scheme, this paper describes a three dimensional computer simulation to predict the flow characteristics in a tangentially fired boiler. The model is applied to a 600?MW boiler modeling under different operating conditions of reverse swirl of secondary air. The numerical results achieve reasonable agreement with experimental data. The calculated results of flow field, the pressure distribution, the relative diameter of tangential circle, angular momentum flux in furnace and the velocity distribution index in horizontal gas pass are analyzed in detail. And then the effects of the reverse swirl of secondary air on flue gas imbalance are discussed. Finally a reasonable operating condition of the reverse swirl of secondary air is presented.

Cause Analysis and Countermeasure of Gypsum Rain in Coal-fired Power Plants

Focusing on the phenomenon of gypsum rain while wet desulphurization(WFGD) were adopted in coal fired power plant without GGH, the paper studied and put forward the solutions : (1) desulfurization facilities related equipment modification;(2) optimal operation of existing desulfurization facilities.

Sliding Mode Predictive Control of Main Steam Pressure in Coal-fired Power Plant Boiler

Since the combustion system of coal-fired boiler in thermal power plant is characterized as time varying, strongly coupled, and nonlinear, it is hard to achieve a satisfactory performance by the conventional proportional integral derivative (PID) control scheme. For the characteristics of the main steam pressure in coal-fired power plant boiler, the sliding mode control system with Smith predictive structure is proposed to look for performance and robustness improvement. First, internal model control (IMC) and Smith predictor (SP) is used to deal with the time delay, and sliding mode controller (SMCr) is designed to overcome the model mismatch. Simulation results show the effectiveness of the proposed controller compared with conventional ones.

Computational Modeling of Tangentially Fired Boiler(Ⅱ) NO_x Emissions

The paper describes numerical and experimental study on reduction of NOx emissions in a 600 MW tangentially fired boiler furnace under different operating conditions. A simplified NOX formation mechanism model, along with the gas-particle multiphase flow model, is adopted. The prediction yields encouraging results as compared to experimental data.

Fired Models of Air-gun Source and Its Application

Air-gun is an important active seismic source.With the development of the theory about air-gun array,the technique for air-gun array design becomes mature and is widely used in petroleum exploration and geophysics.In order to adapt it to different research domains,different combination and fired models are needed.At the present time,there are two fired models of air-gun source,namely,reinforced initial pulse and reinforced first bubble pulse.The fired time,space between single guns,frequency and resolution of the two models are different.This comparison can supply the basis for its extensive application.

Influence of CRT Glass Quantity on the Properties of Red Mud-CRT Glass Ceramics Fired at Different Temperatures

This paper reports the production of ceramics using CRT(cathode ray tube)glass and red mud by varying the amount of waste glass and firing from 700-950℃.The raw materials were characterized using chemical composition,IR(infra-red spectroscopy),XRD(X-ray diffraction),DSC-TGA(differential scanning calorimetry-thermo gravimetric analyses)and SEM(scanning electron microscopy)analysis.The ceramic specimen was produced by mixing a constant quantity of red mud and 0%-40%of waste glass,then firing from 700-950℃.The linear shrinkage,water absorption,apparent porosity,bulk density,weight loss on ignition,flexural strength and chemical resistance test were used to evaluate the produced ceramics.Raw materials had good fluxing properties which were improved with firing.All the specimens produced had water absorption values below the maximum value of 20% specified by the norm for roofing tiles while specimens with 30%-40% CRT glass and fired at 850°C,and specimens with 20%-40% CRT glass and fired at 950℃ had water absorption values below 10%,which is the norm for ceramic tiles.For specimens 0%-40% CRT glass fired at 950℃,specimens 5%-40% CRT glass fired at 850℃,specimens 10%-40% CRT glass fired at 750℃ and specimen with 20%CRT glass fired at 700℃,water absorption values were all lower than 17% which is ASTM C62 specifications for bricks.The norm of flexural strength for floor tiles>25 MPa but all values were less than 25 MPa.The ceramic shows a maximum loss of 0.10%in HNO3 against 0.06%for NaOH.The two waste materials can effectively be used to produce ceramic materials with good properties.

INTRODUCTION TO INCONEL ALLOY 740: AN ALLOY DESIGNED FOR SUPERHEATER TUBING IN COAL-FIRED ULTRA SUPERCRITICAL BOILERS

Chinese utilities as well as those worldwide are facing increased demand for additional electricity, reduced plant emissions and greater efficiency. To meet this challenge will require increasing boiler temperature, pressure and coal ash corrosion resistance of the materials of boiler construction of future coal-fired boilers. A new nickel-based tube alloy, INCONEL^R alloy 740, is described aiming at meeting this challenge. Emphasis will be on describing the alloy＇ s mechanical properties, coal-ash and steam corrosion resistance. Microstructural stability as a function of temperature and time is addressed as well as some of the early methodology em- ployed to arrive at the current chemical composition.

MOSSBAUER SPECTROSCOPIC STUDY OF FIRED SHENQIU METEORITES

The Shenqiu meteorite was investigated by Mossbauer spectroscopy at room temperature, atomic absorption, X-ray diffraction and scanning electron microscopy. In order to determine fired conditions of the meteorite which occurred during the meteorite fall, Shenqiu meteorite samples were fired in an oxidizing atmosphere and a reducing atmosphere at temperatures up to 1300℃, respectively. These samples also were fired at 800, 1000 and 1200 ℃ respectively for different time (up to 24 h).

Characterization of Fired Clay Bricks for an Economic Contribution of the Exploitation of Thicky Clay Deposit

Clay materials from Thicky in Thiès district (Senegal) are very abundant and could be used for the production of clay brick for the construction industry in Senegal and the surrounding countries. The geophysical, geotechnical, and thermal studies carried out did lead to a better comprehension of the potential of the area for clay production. It also allowed determining the physical and chemical characteristics of the clays for their use in order to make fired clay bricks. Different types of fired clay brick were produced with Thicky’s clays. The study of the physical, mechanical and thermal parameters of these raw materials and bricks has given very satisfactory results compared to the standards in use. It is noted a good ceramic behavior, and there is no deterioration observed after firing at 900°C until low residual moisture of about 3% (on a dry basis), a smooth texture with a beautiful appearance, a low loss on ignition, a low shrinkage value of less than 1% (dry), moderate water absorption and also good compressive strength. The study of thermal properties on a brick wall by the asymmetric lime plane method gives satisfactory effusivity and thermal conductivity values which are respectively equal to 746.48 J·K-1·m-2·s-1/2 and 0.42 W·m-1·k-1 with a thermal resistance of 0.0028 m2·K·W-1.

THE ENVIRONMENTAL CHARACTERISTICS OF FOREST LAND AND THE TECHNIQUES OF REFORESTATION IN FIRED LAND IN DAXING'AN MOUNTAINS

Analysis of nature environmental condition and evalwtion of selection and integration ofteclmiques have been carried out in Daxing’an mountains from 1987. The character of soil generaion in this area is influenced by the frigid, coniferous forest vegetation, weather, glacier and late soil formation process. Syntliesis teclmiques for high yield plantation include high seedling quality,suitable site preparation and eftbctive protectioll measures for yoimg trees.

Dynamic Performance of On-off Operation for a Small Scale Direct Fired Absorption Chiller

A part load operation by turning the burner on and off intermittently is effective for a small scale direct fired absorption chiller. The dynamic performance of the system has been investigated. The relationship between pressure, temperature and concentration of the lithium bromide solution have been analyzed. The result obtained indicates that the pressure of the high pressure generator and the temperature of the exhausted smoke are the most sensitive parameters. It is also found that the transition time from a full load to a part load condition is quite long, and part load relative cooling capacity is almost near the intermittent running time ratio and oil consumption ratio.

Temporal and spatial analysis of vegetation fire activity in the circum-Arctic during 2001–2020

Vegetation fires become the concern worldwide due to their substantial impacts on climate and environment,and in particular in the circum-Arctic.Assessing vegetation fires and associated emissions and causes can improve understanding of fire regime and provide helpful information for vegetation fires solution.In this study,satellitebased vegetation fires and emissions during 2001–2020 were investigated and contributions of different types of fires were analyzed.Furthermore,climate anomalies related to extreme vegetation fires were explored.The main results showed that the region south of the Arctic circle(50°N-67°N)experienced a greater number of vegetation fires compared to the Arctic(north of 67°N).During 2001–2020,interannual variability of vegetation fires between 50°N and 67°N appeared to be decreasing while emissions(including carbon,dry matter,PM_(2.5),and BC)appeared to be increasing overall,which were contributed by the increasing summer boreal forest fires in this region largely.In the Arctic,vegetation fires and emissions increased in recent years distinctly,and those were dominated by the summer forest fires.Spatially,large increases of vegetation fires were located in the eastern Siberia and northern North America while large decreases were located in the northwestern Eurasia mainly.Additionally,in the Arctic,the unprecedented vegetation fires were observed in the eastern Siberia and Alaska in 2019 and in the eastern Siberia in 2020,which could be attributed to high pressure,high near-surface temperature,and low air moisture anomalies.Meanwhile,obvious anticyclonic anomalies in Alaska in 2019 and in the eastern Siberia in 2020 and cyclonic anomalies in the western Siberia in 2019,also played an important role on fire occurrences making drier conditions.

Characterization of Clay Materials and Performance Evaluation of Fired Clay Composites Made for Low-Cost Housing

This study deals with the physico-chemical, mineralogical and geotechnical characterization of alluvial clays from Batchenga in Cameroon with a view to their use as building materials for housing. The alluvial clay (Arg.All) was collected in the locality of Batchenga at the village Natchigal (4˚20'40''N and 11˚37'40''E at 378 m altitude) and was fired between 900˚C and 1100˚C. Characterization was performed by XRD, XRF, DTA/DTG, and firing tests. XRD, XRF, DTA/DTG infrared analysis methods were performed on these clays. The linear shrinkage, mechanical strengths, water absorption, porosity and density were measured on the fired products. The results obtained show that the major oxides are for the Arg.Lat SiO2 (72.13%), Al2O3 (14.1%), Fe2O3 (4.45%) and for the Arg.All: SiO2 (48.91%), Al2O3 (23.79%), Fe2O3 (9.54%). The fired products based on alluvial clay, present the flexural strength of 4.45 MPa at 900˚C and 6.80 MPa at 1100˚C. As for those based on lateritic clay, the flexural strength is 0.53 and 0.76 MPa respectively at 900 and 1100˚C. The porosity is 33.69% at 900˚C and 22.93% at 1100˚C for the alluvial clay and 39.55% at 900˚C and 36.01% for the lateritic clay at 1100˚C. Water absorption is 18% to 11.16% for alluvial clay and 22.43% to 21.16% for lateritic clay at 900˚C and 1100˚C respectively. These results suggest that alluvial clay and its firing products have better physico-chemical, geotechnical and mechanical characteristics regardless of the firing temperature of the manufactured products. The addition of degreaser is recommended to improve the mechanical performance of lateritic clay.

Mercury Emission From Coal-fired Power Plants in China

燃煤是最大的人为汞排放源之一，燃煤电厂的汞排放控制问题也越来越为人们所关注。该文将目前公布的中国电厂的汞排放数据进行筛选汇总，得到18个电厂的汞排放数据，通过对比和分析，总结出了符合我国燃煤电厂特点的一般性汞排放规律。结果表明：与美国煤种相比，我国的燃煤具有低氯、高灰的特性，这不利于汞的排放控制；循环流化床燃烧可能会因燃尽率的不同而较煤粉炉燃烧易获得较高的Hgp；空气污染控制设备的使用能够有效地减少汞排放，选择性催化还原＋静电除尘器／布袋除尘器＋石灰石-石膏湿法脱硫（SCR＋ESP／FF＋WFGD）组合的平均脱汞率可达71．48％；SCR的大规模应用可能会将汞大量转移到飞灰和脱硫石膏中，带来二次污染的问题。