Understanding the decomposition and fire performance processes in phosphorus and nanomodified high performance epoxy resins and composites

This paper investigates the decomposition mechanism and fire performance of high performance epoxy amine resins and laminate systems, using thermogravimetry (TGA), energy dispersive spectroscopy (EDS), cone calorimetry and Fourier transform infra-red spectroscopy (FTIR). Two different, commercially-important epoxy resins, tetraglycidyl methylene dianiline (TGDDM) and diglycidyl ether of bisphenol A (DGEBA) have been cured separately with diethyl toluene diamine (DETDA) and bis(4-aminophenoxy)phenyl phosphonate (BAPP) and their relative combustion performance has been examined and discussed in terms of their decomposition profile. This paper highlights the close relationship between char yields (TGA and cone calorimetry) and thermal decomposition with the peak heat release rate, highlighting the role of the condensed phase in minimizing combustion. The lower decomposition temperatures and higher char yields of the tetra-functional epoxy (TGDDM) are therefore seen to provide superior fire performance compared to the bi-functional (DGEBA) epoxy. FTIR shows that the decomposition occurs through initial cleavage of P-O-C bonds in preference to other covalent bonds, which allows dehydration and subsequent charring and/or chain scission. TGA demonstrated that the laminated systems did not show a significant difference to the neat resin systems, with respect to initial decomposition of the network and the thermal stability of the char layer. Nanoclay addition was also found to have little effect upon degradation and fire performance.     

Physicochemical processes in modified fire- and thermal-protective two-layer filled epoxy polymers under the action of fire sources

A carbonized layer was formed by means of thermal treatment of the surfaces of glass- and organo-fiber plastics based on an epoxy binder premodified with flame-retardant phosphorus-containing compounds. To improve flame resistance of the carbonized layer, the active coats of swelling type which filled the cracks and pores were studied. The obtained data on the construction fire resistance confirmed the advantages of the two-layer fire and thermal protective coats over conventional ones.Izhevsk. Translated from Fizika Goreniya i Vzryva, Vol. 31, No. 2, pp. 73–79, March–April, 1995.     

Probabilistic analysis of transport-reaction processes over catalytic particles: Theory and experimental testing

We developed a probabilistic theory of transport-reaction processes over various types of configurations of catalytic particles, particularly for a single particle. The theory describes a single pulse-response experiment which is similar to the single pulse temporal analysis of products (TAP) experiment. The analysis is based on the general theory of Brownian motion with “killing” and the Feynman-Kac formula. Different diffusion-reaction problems, particularly the problem “diffusion-very fast reaction” (infinite rate reaction), have been analyzed. In the latter case, the probability for a reactant to be converted equals a purely geometric characteristic, namely, the probability for a reactant molecule to hit at least one catalyst particle in a configuration of particles. Solving a boundary value problem, the probability of conversion can be found as a function of the apparent kinetic parameter. Based on experimental data on exit flow and conversion this parameter can be extracted. Experimental data in studies of CO oxidation over a single particle of Pt catalyst show a qualitative agreement with data from computational experiments based on the developed probabilistic theory. For two-particle catalyst configurations, it was found computationally a non-trivial dependence of the reactant conversion on some geometric characteristics, especially the distance between particles. A distance was found for which conversion is highest.     

Relationship between fire resistance and fire tolerance

Much of the information accumulated on the fire resistance of ‘dividing’ elements can be utilized in the design of buildings for fire safety, if the fire tolerance values are converted into fire resistance. Three methods of conversion, one based on the concept of equal temperature-time areas, the second on the concept of equal maximum temperatures, and the third, Law method, are critically examined and handy conversion tools presented. In the case of the ‘key’ elements of buildings, basing the fire safety design on fire resistance information is not recommended.     

阻燃防火硅橡胶研究进展

总结了国内外当前阻燃防火硅橡胶的研究进展,并重点介绍了阻燃剂和防火填料对硅橡胶性能的影响.在阻燃剂方面,介绍了目前常用的阻燃剂及其阻燃机理;在防火填料方面,对应用比较广泛的防火填料进行了介绍,并对其成瓷机理进行了阐述;最后提出了未来阻燃防火硅橡胶的研究方向.     

Machine learning-based predictive control of nonlinear processes. Part I: Theory

This article focuses on the design of model predictive control (MPC) systems for nonlinear processes that utilize an ensemble of recurrent neural network (RNN) models to predict nonlinear dynamics. Specifically, RNN models are initially developed based on a data set generated from extensive open-loop simulations within a desired process operation region to capture process dynamics with a sufficiently small modeling error between the RNN model and the actual nonlinear process model. Subsequently, Lyapunov-based MPC (LMPC) that utilizes RNN models as the prediction model is developed to achieve closed-loop state boundedness and convergence to the origin. Additionally, machine learning ensemble regression modeling tools are employed in the formulation of LMPC to improve prediction accuracy of RNN models and overall closed-loop performance while parallel computing is utilized to reduce computation time. Computational implementation of the method and application to a chemical reactor example is discussed in the second article of this series.     

Ceiling heat transfer during fire plume and fire impingement

The impingement of turbulent fires and fire plumes on a horizontal ceiling was considered. Free flame heights, impinging flame lengths along the ceiling and ceiling heat fluxes were measured for both unconfined and confined ceilings. The study was limited to the initial stage of ceiling heating by fire under conditions where convection dominates the flow. Fire sources were simulated by burning liquid methanol, ethanol, 1-propanol or n-pentane from the top surface of a cylindrical wick. Test variables include fire heat release rate of 50–7890 W, ceiling diameters of 610 and 660 mm, ceiling heights of 58–940 mm, wick diameters of 10–107 mm and curtain wall lengths (for confined ceilings) as large as the ceiling height. Simplified models were employed to suggest expressions for data correlation. Flame lengths increased up to 40% when the ceiling was confined. Ceiling heat fluxes were relatively independent of position in the stagnation region (radius along ceiling <20% of the ceiling height). Heat fluxes in the stagnation region for plumes were 25–40% of those measured for impinging jets at comparable conditions. In the ceiling jet region, at larger distances from the point of impingement, the heat flux decreased with increasing radius, in agreement with other studies. Confinement tended to increase ceiling heat fluxes in both regions. Ceiling heat fluxes for impinging flames and plumes were approximately the same, for flame lengths along the ceiling up to 25% of the ceiling height; however, stagnation point heat fluxes decreased for longer flame lengths.     

Smoke and fire assessment with the fire propagation test

Assesing the total potential fire hazard of modern interior surfacing of buildings requires a method which includes determination of smoke toxicity concurrently with fire and smoke production parameters. The Fire Propagation Box Test (British Standards Institution BS 476, Part 6) is a promising contender. It has been examined in the flaming mode as a method for evaluating smoke production concurrently with fire propagation indices for a range of surfacings, rather than resorting to a separate procedure by using fans with the same apparatus, as described in the former British Standards Institution Draft for relation to rate of burning the concurrent procedure is shown to be the more valied method.     

绿色化学与消防

在绿色化学的理论与原则基础上,提出了消防友好过程的概念。通过分析比较绿色工艺流程与传统工艺流程在火灾危险性方面的差异,指出绿色化学的研究与消防安全密切相关。     

Design car fire size based on fire statistics and experimental data

Passenger vehicle fires present a significant fire hazard in enclosed car parks. Accordingly, this hazard is often used as a design fire scenario for the application of fire protection systems. Specific fire protection standards, like NFPA 88A:2019 and NFPA 502:2020 in the United States (US) or BS 7346-7:2013, NBN 21-208-2:2014, VDI 6019-1:2006, NEN 6098:2010 and ITB 493:2015 in Europe, provide varying requirements for car park fire protection. Car parks fire strategies, especially when smoke control systems are used, often make use of performance-based methods, in which fire growth (ie, heat release rate [HRR]) plays a fundamental role. The chosen HRR can influence the specification of car park construction and on smoke control system calculations. This article presents a review of 44 full-scale car fire tests together with Polish and British passenger car fire statistics from the last 8 years. Based on the collected data and the averaged tests, HRR values provided in this article could assist local authorities and stakeholders determine optimal fire safety design criteria for car parks.     

Transition of the forest ground fire to crown fire

Translated from Fizika Goreniya i Vzryva, Vol. 26, No. 6, pp. 27–35, November–December, 1990.     

Photochemical ECE and DISP processes. The self-inhibiting disproportionation (SID) mechanisms. Theory and experiment

Channel electrodes are used to characterize the photochemical DISP2 mechanism in respect of the photoelectro-reductions of

1. (i) 9,10-diphenylanthracene,

2. (ii) benzophenone and

3. (iii) 4-fluorobenzophenone.

Quantitative measurements show that the simple DISP2 mechanism requires extension to allow for the possibilities of first a conproportionation step acting as a back-reaction to the disproportionation, and of second quenching of the excited state which leads to reaction. Both these steps, if present, serve to inhibit the overall DISP2 process. Accordingly a general scheme of Self-Inhibiting Disproportionation (SID) Mechanisms is introduced and characterized in the channel electrode geometry by computer simulations. A general protocol is established for identifying the various possible sub-cases of the general SID mechanism and illustrated with reference to the three experimental systems of interest, in all of which both conproportionation and quenching are shown to be mechanistically significant.     

多层民用建筑消防水箱和消防水泵的作用及设置建议

本文针对多层民用建筑设置消防水箱和消防水泵的现状进行分析,对因为国家消防技术规范中规定不够明确导致消防水箱和消防水泵设置不合理的问题,从实际作用出发,提出了应考虑市政水源压力、管网条件、消防队保护范围及建筑物规模、灭火用水量、经济条件等因素,分别、合理设置消防水箱和消防水泵,使建筑物消防给水系统兼顾消防安全与经济效率。     

圆筒形地下立体停车库火灾火源位置与火势蔓延规律研究

选取一个典型的圆筒形地下立体停车库作为研究对象，运用star-ccm+软件，采用数值模拟的方法对车库内自然通风条件下的火灾场景进行模拟计算。分别选择负一层、负六层以及负十层作为起火点，计算得出：火源位置越深入地下，着火车位顶棚中心温度越高，最高可达942℃，与起火点同层的车位顶棚中心温度均高于200℃。当某车辆发生火灾后，其相邻车辆、上方车辆、相对车辆将分别在起火后的240、312、322 s左右被引燃；火源位置越往下，引燃附近车辆的时间越短。同时，通过计算值与理论值的对比，讨论了计算火源附近车辆被引燃时间理论公式的适用性。     

What fire statistics tell us about our fire and building codes for housing and small buildings and fire risk for occupants of those structures

Annual reports on fire losses in Canada and the United States are in part, report cards on the efficacy of fire safety provisions in our building and fire codes and on the efforts to reduce risk for the occupants of those buildings. This paper attempts to assess what recent fire‐loss statistics indicate about how successful those efforts have been. Copyright © 2002 John Wiley & Sons, Ltd.     

消防稳压装置在消防系统中的应用

阐述了消防稳压装置在消防系统中的应用情况。介绍了装置的工作原理、特点和日常注意事项。