Towards a methodology for the characterization of fire resistive materials with respect to thermal performance models

A methodology is proposed for the characterization of fire resistive materials with respect to thermal performance models. Typically in these models, materials are characterized by their densities, heat capacities, thermal conductivities, and any enthalpies (of reaction or phase changes). For true performance modelling, these thermophysical properties need to be determined as a function of temperature for a wide temperature range from room temperature to over 1000°C. Here, a combined experimental/theoretical/modelling approach is proposed for providing these critical input parameters. Particularly, the relationship between the three‐dimensional microstructure of the fire resistive materials and their thermal conductivities is highlighted. Published in 2005 by John Wiley & Sons, Ltd.     

Lightweight fire protection of steel framed buildings: Comments on russian experience in use of light weight fire protection coverings for steel frame buildings

In recent year, increased attention, linked to the use of new structural design criteria and materials, has been given to maintaining the integrity of buildings and structures exposed to fire. Structures are now designed using lighter structural shapes and consequently differ from earlier, more traditional buildings, in terms of their resistance to the effects of the high temperature of fire. Contemporary structures are less expensive. Advance in building construction technology also result in faster erection.     

Smoke problems in buildings on fire: A TNO research project

The activities within the framework of TNO's research project on smoke problems in buildings on fire are reviewed. Two aspects will be dealt with extensively: smoke production and smoke movement. Furthermore, possible application of its finding will be discussed. The article reflects the state of the art at the end of 1978. In the meantime, the research programme has been concluded.     

Australian studies on fire hazard tests for internal linings of buildings

The Australian Standard ‘Test for Early Fire Hazard Properties of Materials’ (AS 1530 Part 3, 1976) has been studied in detail as a method of assessing the fire performance of plastics wall linings under the conditions of early fire development in a room. A particular feature of the standard test is that four parameters characterizing the reaction to fire are measured concurrently. Results from the standard test have been compared to corner-wall burns involving the same parameters as in the standard test. The suitability of these parameters and the ability of the standard test to rank the behaviour of the materials in the same order as indicated by corner-wall burns is discussed. A general relationship between ignition time and flame spread was observed and is discussed as support for the concept of concurrent measurement of different reaction-to-fire parameters under the one test procedure and condition.     

Overall stability analysis of oversized steel‐framed buildings in a fire

Our present paper summarizes the shortcomings in the current fire‐resistant design of oversized steel structures and proposes a method for overall stability analysis of steel structures in the event of fire. The Fire Dynamics Simulator (FDS) software platform–based large‐eddy simulation technology can accurately reflect the environment in a fire scenario and correctly predict the spatial–temporal change in the smoke temperature field within an oversized space. Adopting the FDS software and finite element structural analysis (ANSYS) coupling can fundamentally overcome the natural defect of adopting the International Organization for Standardization (ISO) standard curve (or other indoor homogeneous temperature increase curves) that substitutes a point for the overview of a field. They reflect the structural additional internal force and internal force redistribution incurred by the gradient temperature difference of the spatial–temporal changing nonhomogeneous temperature field and both theoretically and technically realize the analysis of structural heat transfer and mechanical properties in a natural fire. Furthermore, a modified model to predict the steel temperature curve in localized fire is also proposed. The localized fire in large spaces can be treated as a point fire source to evaluate the flame thermal radiation to steel members in the modified model. Copyright © 2014 John Wiley & Sons, Ltd.     

Effect of phosphorus-nitrogen-containing fire retardants on thermal decomposition of polyethylene terephthalate

It was found that T-2 fireproofing compound, a mixture of methylphosphonic acid diamide ammonium salt and ammonium chloride, added to PETP alters the direction of the chemical processes in the basic stage of thermal decomposition of the polymer and increases the oxidative stability of carbonized residues, which decreases the inflammability of PETP. The oxygen index of protected PETP is 27–29% with a 5–7% concentration of T-2 fireproofing compound.Moscow State Textile Academy. Translated from Khimicheskie Volokna, No. 1, pp. 31–33, January–February, 1994.     

Electrochemical modeling of intercalation processes with phase field models

In this paper, we apply phase field models to move beyond Fick’s law in describing Li diffusion in secondary battery electrodes. Phase field models are potentially more accurate and allow simpler tracking of phase boundaries than Fick’s equation. The phase field models are implemented using the highly accurate but fast Chebyshev-spectral method. Using the phase field we investigate to what extent non-Fickian behavior can affect results from experimental techniques for measuring diffusion coefficients, such as Galvanostatic Intermittent Titration Technique (GITT) and Potentiostatic Intermittent Titration Technique (PITT). We show that GITT and PITT can still accurately measure the diffusion coefficient in systems described by phase field models even when significant gradient energy terms are present.     

运煤栈桥自动喷水灭火系统设置国内外标准对比分析

为提高我国运煤栈桥的自动喷水灭火系统的设计水平,针对不同的运煤系统类型设置自动喷水灭火系统的国家标准和美国标准进行对比分析,包括火灾危险等级划分、喷水强度设计参数、开式或闭式喷水系统的选择等。通过国内外标准规范设计参数分析,得出美国标准略高于国家标准。     

甲烷爆炸对建筑物内外压力场分布的影响

天然气泄漏导致的预混爆炸,会严重威胁周围人员的生命及财产安全,因此掌握气体预混爆炸在建筑物周围产生压力场的分布至关重要。基于Fluent软件,建立了适用于甲烷无约束爆炸超压的计算模型,并通过实验数据对其修正,结果表明:在化学计量浓度下参与燃烧爆炸的预混气体体积约为总体积的1/3,即当量体积。在此基础上建立了适用于甲烷约束爆炸的仿真模型,分析了建筑物高度和宽度对建筑周围压力场的影响,并进一步研究了气体爆炸对建筑物内部压力场分布的影响。结果表明,在建筑物不失效前提下,背对爆炸源一侧中上部为较安全区域,在紧急爆炸事故中,盲目的向下逃生,反而容易受到爆炸超压的强烈冲击。     

Studies on thermal stability of modified polycarboxylate cements

Dental cement compositions made by mixing poly(acrylic acid-co-acrylamide) and mixtures of zinc oxide and cryolite (Na₃AIF₆) in various proportions of 10–50 wt.-% (w/w) were cured at room temperature. From thermogravimetric analyses of the samples, the integral procedural decomposition temperatures (IPDT), maximum decomposition temperatures, activation energies and frequency factors were evaluated. The cured cement sample containing 20 wt.-% cryolite in the filler mixture is thermally very stable.     

风机功率对火灾温度场影响的数值模拟

研究危险化学品生产作业场所的风机功率对火灾温度场影响的变化特性,使用FDS模拟计算软件PyroSim,对真实环境下火灾发生、发展过程进行数值模拟。以物质的化学性质为依据,计算火源功率,对0、1.5、3.0、6.0、9.0、12.0 kW等6种不同风机功率下的火灾发生过程进行模拟计算。研究结果表明:风机在火灾规模较小时作用有限,在较大火灾发生时影响很大。大功率风机对火源周围,尤其是火源下风向处的温度场和热流密度有很大影响,并且大功率风机能够较好地控制火源周围的温度,防止热流密度过大对周围的人和物造成损害。     

关于折边锥形封头设计问题的研究

研究了ＧＢ１５０ ８９《钢制压力容器》中有关折边锥形封头的设计方法,阐述了其理论依据。同时认为其中有不合理之处,并对此提出了一些意见供工程人员参考。     

对高层民用建筑消防给排水设计中几个疑难问题的探讨

根据实践经验,总结出若干高层民用建筑消防给排水设计疑难问题,值得提出探讨和交流,以便引起广大审核人员特别是初学者的注意,防止类似的错误发生。     

Phosphorylation of phosphazenes and its effects on thermal properties and fire retardant behavior

Methods for the incorporation of phosphate and phosphonate units into the side groups of phosphazenes, at both the high polymeric and cyclic trimer levels, are described and evaluated. Halogenated organophosphates were used as the phosphorylating agents and were allowed to react with hydroxyl‐ or lithio‐functionalized phosphazenes. Well‐defined phosphorylated cyclic trimers were synthesized from the hydroxyl‐functionalized precursors, and these were examined as flame‐retardant additives to polystyrene. The thermal stabilities of the high polymers made by this route were analyzed by TGA.     

Studies on thermal degradation of cellulose and cellulose phosphoramides

Reaction of cellulose with hexamethylphosphoric acid triamide has been investigated under various physical conditions. Dimethylamine hydrochloride was found to be an efficient catalyst for the system. The thermal degradation of cellulose and its phosphoramide products in air was studied by DTA, TG, and DTG techniques from ambient temperature to 500°C. The data were processed for the various thermodynamic parameters following the methods of Freeman and Carroll, of Broido, and of Dave and Chopra. The energies of activation, E_a, for the degradation for various cellulose phosphoramide samples were found to be in the range of 92–136 kJ mol^?1. These values were found to decrease with increase in the degree of substitution. A mechanism for the thermal degradation of cellulose phosphoramide has been proposed. The IR spectra of char residues of cellulose phosphoramide gave an indication of the formation of compounds containing C?O and P?O groups.     

Studies on thermal behavior of imidazole diamine based benzoxazines

The objective of the present work is to develop a novel type of structurally modified benzoxazines with improved performance characteristics using imidazole core based diamine with formaldehyde and different types of phenolic compounds in order to utilize them for high‐performance applications. In this work, an attempt has been made to bring down the polymerization temperature of the benzoxazine monomers, which is one of the most deficient factor restrict the applications of benzoxazines, when used in the form of adhesives, sealants, encapsulants, and matrices with other substrates, though they possess numerous advantages and valuable properties than those of other available thermosets. In this context, in this study, two approaches have been adopted to bring down the polymerization temperature, viz., (i) the development of structurally modified benzoxazine monomers with imidazole core and (ii) an incorporation of varying nature of chemical compounds as catalysts, to lower the polymerization temperature and to enhance the thermal stability and char yield. Three types of benzoxazines were developed using imidazole core based diamine with monohydric phenols and formaldehyde, at appropriate conditions. The molecular structure of benzoxazines was confirmed from Fourier transform infrared spectroscopy and ¹H‐nuclear magnetic resonance analysis. From data, it was observed that the imidazole diamine based benzoxazines prepared from 1‐naphthol exhibits lower curing temperature of about 192 °C than that of other samples studied in this work. In addition, the influencing effect of catalysts viz., 4‐hydroxy acetophenone, 4‐hydroxy benzaldehyde, 4‐hydroxyphenyl maleimide, and thiodipropionic acid (TPA) on thermal properties of benzoxazines also was studied. Among the catalysts, it was found that the TPA is the most efficient catalyst. In the case of imidazole diamine based benzoxazines prepared from cyanophenol, the TPA reduces value of polymerization temperature (T_p) from 217 to 167 °C. The thermogravimetric analysis indicates that thermal stability of the benzoxazines are improved to a significant extent when 10 wt % catalysts were incorporated into the system. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46562.     

Experimental study on fire behaviors of external thermal insulation composite system under vertical radiation

Using a vertical thermal radiator, we perform a set of experiments on the external thermal insulation composite system (ETICS) and pure extruded polystyrene (XPS). Several important parameters, including time to ignition, mass loss, and sample temperature, were measured. The combustion degree of XPS used during the experiments was B1 and B2. Results show that the whole burning process can be divided into 3 typical stages. Because of the protection effect of the outer layer of ETICS, the burning process of ETICS was noticeably different from that of pure XPS. The experimental results indicated that the protection effect of the outer layer weakened the difference between B1 and B2 flame‐retardant XPS. The time to ignition was increased under the effect of outer layer, while the core material (XPS) was easier to be ignited when the outer layer falls out. The research results are useful to the theoretical and numerical study on the fire characteristics of foamed polymer under vertical thermal radiation condition.     

兖州矿区循环经济模式初步研究

兖矿集团立足于自身行业特点,积极进行了产业结构调整,延伸了下游产业链,完善矿区及其附属产业经济增长模式,改善矿区生态环境,发展循环经济,初步实现了节能、高效、生态的产业增长方式。在对兖矿集团经济建设现状分析基础上,探讨了其不同产业资源最优利用的循环经济模式。