Software-Based Simulations of Wildfire Spread and Wind-Fire Interaction

Wildfires are complex phenomena, both in time and space, in ecosystems. The ability to understand wildfire dynamics and to predict the behaviour of the propagating fire is essential and at the same time a challenging practice. A common approach to investigate and predict such phenomena is making the most of power of numerical models and simulators. Improved and more accurate methods for simulating fire dynamics are indispensable to managing suppression plans and controlled burns, decreasing the fuel load and having a better assessment of wildfire risk mitigation methodologies. This paper is focused on the investigation of existing simulator models applicable in predicting wildfire spread and wind fire interaction. The available software packages are outlined with their broad range of applications in fire dynamic modeling. Significance of each work and associated shortcomings are critically reviewed. Finally, advanced simulations and designs, accurate assumptions, and considerations for improving the numerical simulations, existing knowledge gaps in scientific research and suggestions to achieve more efficient developments in this area are revisited

Nonlinear vibration analysis of a rotor supported by magnetic bearings using homotopy perturbation method

In this paper, the effects of nonlinear forces due to the electromagnetic field of bearing and the unbalancing force on nonlinear vibration behavior of a rotor is investigated. The rotor is modeled as a rigid body that is supported by two magnetic bearings with eight-polar structures. The governing dynamics equations of the system that are coupled nonlinear second order ordinary differential equations (ODEs) are derived, and for solving these equations, the homotopy perturbation method (HPM) is used. By applying HPM, the possibility of presenting a harmonic semi-analytical solution, is provided. In fact, with equality the coefficient of auxiliary parameter (p), the system of coupled nonlinear second order and non-homogenous differential equations are obtained so that consists of unbalancing effects. By considering some initial condition for displacement and velocity in the horizontal and vertical directions, free vibration analysis is done and next, the forced vibration analysis under the effect of harmonic forces also is investigated. Likewise, various parameters on the vibration behavior of rotor are studied. Changes in amplitude and response phase per excitation frequency are investigated. Results show that by increasing excitation frequency, the motion amplitude is also increases and by passing the critical speed, it decreases. Also it shows that the magnetic bearing system performance is in stable maintenance of rotor. The parameters affecting on vibration behavior, has been studied and by comparison the results with the other references, which have a good precision up to 2nd order of embedding parameter, it implies the accuracy of this method in current research

Smart coating in protective clothing for firefighters : an overview and recent improvements

Recently, new developments in the design and performance optimization of smart mechanisms associated with natural and man-made hazards have progressed considerably. This is mainly owing to advances in smart sensing mechanisms including communication and data technologies. This work provides a detailed overview of existing improvements on smart hazard monitoring equipment and materials applied in textile sensing systems. Given that fire is one of the most common disasters in many countries such as Australia, and every year many firefighters are affected by these unfortunate incidents, the focus of this study is on firefighters' protective clothing Fire Fighter Protective clothing. This review provides a unique opportunity to study smart sensing systems in coating technologies, potentially provides more effective techniques for training and better safety protocols of fire fighters. It aims to revisit the existing advances and address recent challenges and opportunities for improvement in the domain of smart coating and fire protective wearables. The goal of this review is to provide information about smart coating in protective clothing for firefighters. The capability of some of these clothing in managing thermal stresses, responding to humid environment, monitoring some critical parameters and adapting to the size of the wearers (clothes fabricated with phase change and shape memory substances) made them attractive choice in adjusting specific design features of industrial textiles. Various types of phase change and shape memory substances are defined and a combination of these substances within the structure of fabrics are presented. This paper also provides a detailed review on the heat exposure and capability of the shape memory substances (SMM) and phase change materials (PCM) to delay the heat transfer through fire fighter protective clothing. Referring to the former research, several issues have been detected using such substances. For instance, combination of phase change and shape memory materials needs fundamental improvements with regards to assessment techniques and testing criteria. Additionally, recent improvements in the domain of PCM and SMM including modifying mechanical features, functionality, and durability under different conditions have been informed. It has been suggested that the major problem in developing fabric-Phase Change Materials (PCMs) and Shape memory material (SMM) systems is their usage methods. At last recent developments on wearable monitoring systems applied in the firefighters’ protective gear. Wearable sensors are usually used directly on the body or located on wearable items to monitor information related to firefighters’ safety