Fire Hazard Properties Research Articles

Thermodynamic Calculations of the Main Characteristics of the Combustion Process of Pyrotechnic Nitrate-Metallized Mixtures with Additives of Organic and Inorganic Substances under External Thermal Influences

The aim of the article is to determine the dependencies of the combustion product temperatures of four-component mixtures, the content of high-temperature condensate, and unoxidized metal on the excess oxidizer coefficient, the number of additives, and external pressure using thermodynamic calculations. Modern methods of physicochemical analysis (such as cinephotography and microcinephotography methods, X-ray analysis methods, non-contact and contact temperature measurement methods), nonlinear thermal conductivity and thermal stability methods, as well as mathematical and experimental-statistical modeling, were employed to investigate the influence of elevated heating temperatures (up to 800 K) and external pressures (up to 107 Pa) on the ignition and combustion processes of pyrotechnic products. Standard pyrotechnic equipment was used to test pyrotechnic product samples under specified conditions. Calculations based on models were conducted in real-time and dialog mode on computer devices that meet modern requirements for the use of specialized software. The results of thermodynamic calculations are presented for the dependencies of combustion product temperatures of multicomponent pyrotechnic mixtures based on powders of metal fuels (magnesium, aluminium), nitrate oxidizer (sodium nitrate), additives of organic and inorganic substances (paraffin, sodium fluoride), and the content of high-temperature condensate and unoxidized metal depending on the excess oxidizer coefficient α = 0.1…4.0, the amount of paraffin additive εp = 0…0.2, sodium fluoride additive εf = 0…0.06, and external pressure P = 105…107 Pa. Based on the obtained results of thermodynamic calculations, statistical models in the form of regression dependencies of the specified combustion characteristics on their technological parameters and external conditions have been developed. These models enable the determination of fire hazardous properties of mixtures in real-time dialog and PC-based scenarios, considering premature initiation of products based on them under external thermal actions.

Revealing patterns in reducing the fire-hazardous properties of insulation made from plant raw materials

An issue related to the use of hemp bundle insulation for building structures is to ensure their fire resistance under the action of a low-calorie ignition source. Therefore, the object of research was the change in the properties of the insulation during fire protection with its compositions capable of forming a layer of pinocoke under the influence of high temperature. On the basis of experimental data, it was established that at fire protection of insulation with a fire retardant agent, hydrolytic stable ethers containing phosphorus and nitrogen atoms are formed on the surface of the fibers. According to the temperature values and the shape of peaks on the DTA curve, it was established that at fire protection, the height of the peaks decreases and the width increases, which characterize the flow of exothermic transformations and the destruction of hemp fibers. At the same time, it was established that the formed residue has 13.3 % for impregnation and 26.6 % for coating. It has been proven that in the process of thermal action on the fire-resistant coating, the heat insulation process of the insulation consists in the formation of soot-like products on the surface of the material. So, it was determined that the sample did not catch fire, it was charred in the place of the radiation panel, and the burning was not recorded. On the other hand, for a sample of insulation treated with a coating during thermal action, the formation of a heat-insulating layer of foam coke occurred, which inhibits the penetration of heat, the temperature of flue gases did not exceed 100 °C, and the flammability index was 0. The practical significance is that the results were taken into account when designing buildings and structures. So, there are reasons to assert the possibility of targeted regulation of fire protection processes of insulation by applying coatings that form a protective layer on the surface of the material

Study of textile carpet combustion process

Currently, synthetic carpet products are widely used in the home, as they compare favorably with natural ones in terms of technical characteristics. This is due to their high durability, lack of tendency to rot, wide range of colors and relatively low cost of production. However, the ease, ignition and increased flammability of most synthetic carpet products result in rapid spread of fire through them, igniting other products and objects in the vicinity. The sources of the fire are usually matches, cigarettes, careless handling of fire, and short circuits. In this regard, the purpose of the study is to investigate the combustion process of textile synthetic carpet products of "Bal Textile" LLP with justification of the most rational methods of flammability and combustibility assessment. Subject of research: processes of thermo-oxidative destruction of modified polypropylene textile materials and their relationship with fire hazard properties, flammability of fiber-forming polymers. The combustion process of synthetic carpet products of Bal Textile LLP with different Heat Set yarn densities and pile lengths were investigated. Based on the research we have done, it has been concluded that the higher the pile of the carpet, the higher the level of combustion. Carpets melt when ignited and are also colored as a black liquid. The value of the conducted research is that on their basis it is possible to classify materials by degree of combustibility (flammability) and to develop requirements for synthetic carpet products of LLP "Bal Textile" of reduced fire hazard taking into account their possible application in practice.

Экспериментальное определение давления насыщенного пара жидких моторных топлив

Purpose. Currently, new brands of liquid motor fuel are produced, whose fire hazardous properties are not reflected in regulatory documents and reference literature. The values of saturated vapour pressure of petroleum products presented in them differ significantly from each other and that may affect the results of assessing fire and explosion hazard of the facility under protection. The article provides the results of experimental evaluation of motor gasolines and diesel fuel saturated vapour pressure. Methods. Analytical and experimental methods for determining saturated vapour pressure of motor gasolines and diesel fuel have been used during the research process. Findings. The saturated vapour pressures of motor gasoline and diesel fuel of different brands have been determined experimentally. It has been found that saturated vapour pressure of petroleum products is different and varies over a wide range. Research application field. Experimental studies allowed obtaining the numerical value of saturated vapour pressure of currently marketed brands of liquid motor fuel. Conclusions. During the experiments, the values of the saturated vapour pressure of liquid motor fuels, significantly different from those given in the regulatory documents or determined by calculation have been obtained. The application of the obtained results will make it possible to assess fire and explosion hazard of storing flammable liquids in tank farms of the facilities under protection.

Study of the characteristics of organic mining materials affecting their explosive properties

The article analyzes the explosive and fire-hazardous properties of coal dust of various dispersions using the example of coal mine dust. The authors proposed sample preparation methods for obtaining and studying dust fractions with a dispersity of less than 800 microns. The results of a study of the shapes of dust particles are presented. To study the characteristic particle sizes the authors suggested using the optical microscopy method implemented using a LEICA DM 4000 microscope and the “Image Scope Color” information processing application. To assess the reactivity of dust particles, the authors used a simultaneous thermal analysis method implemented using an STA 449 F1 Jupiter with NETZSCH Proteus Software. The results of a thermogravimetric study of narrow fractions of organic coal dust are presented. The influence of dispersion on the explosive properties of dusts has been established. The results obtained showed the need and expediency of further study of precisely fine fractions of explosive dusts of this kind.

Thermal Insulation Products Based on Modified Polyurethane Foam with Fire-Resistant Coating

As part of the study, thermal insulation products based on rigid polyurethane foam (PPU) with a reduced flammability group were obtained. The effect of modification of polyurethane foam with oxidized thermally expansive graphite (OTG) on physical, mechanical and fire hazard properties was studied. A two-component factory-ready system with a G4 flammability group was used as the initial composition for modification. OTG brand: KR 350-80 was used as a modifier, characterized by a degree of expansion of at least 370 ml/g, a temperature of the onset of expansion of 170°C. Products made from polyurethane foam were modified by the method of dispersing OTG in a reactive composition, as well as by applying a fire-retardant coating during injection molding of masses. Samples were made and tests were carried out to determine the flammability group in accordance with GOST 30244. It was established that an increase in the concentration of OTG in the fire retardant coating and the structure of the material reduces the flammability of products, while modification by the dispersion method makes it possible to obtain a material with a flammability group (G3), but has an effect on the technological properties of the initial composition, leads to an increase in the viscosity of the reactive composition and an increase in the density of the products, while the modification of the fire retardant coating with honey does not affect the technological and physical-mechanical properties of the final product, and makes it possible to obtain a flammability group G1–G2 depending on the concentration of OTG.

Analysis of the Application of Fire Protective Composition for Wooden Structures

In construction, coniferous wood is usually used as load-bearing and enclosing structures. Wood is characterized by the ability to ignite and spread combustion when heated in air. Wooden building structures pose a fire hazard, since with an initial impulse of external thermal energy, ignition is possible. In addition, when a fire occurs in buildings and structures where wood is located, a number of dangerous fire factors arise: flames, sparks, heat flow, toxic combustion products, extremely low oxygen concentrations, decreased visibility due to smoke. In this regard, it becomes relevant to treat wood with special compounds that increase resistance to fire. The authors examined the fire hazardous properties of building structures made of wood, analyzed the fire retardant treatment of wooden structures with a special composition; examined the fire hazardous properties of building structures made of wood, the mechanism of pyrolysis, and the effect of fire retardant treatment on the behavior of wood when exposed to fire. The use of fire retardant significantly affected the pyrolysis processes of the samples. The information obtained during the study made it possible to assess the degree of differences in the values of the average weight loss of samples treated with different fire retardants. Samples using a fire retardant composition have a shallower charring depth. Damage associated with thermal exposure is fundamentally different from untreated samples. Treated and impregnated samples exhibit rapid weight loss. This is due to the fact that in treated and impregnated samples, when exposed to high temperatures in the oven, the reactions of dehydration and cross-linking of cellulose molecules are accelerated.

Оценка выполнения условия безопасной эвакуации из детских игровых помещений при пожаре

PURPOSE. Soft children's toys located in children's playrooms are ones of the most dangerous combustible materials. However, their fire hazardous properties, data on which are necessary to calculate the time of blocking escape routes from the above mentioned rooms in case of fire, have not been studied. The study is aimed at assessing the compliance with the conditions for safe evacuation from children's play rooms, taking into account experimental data on the formation of dangerous fire factors when soft toys burn. To achieve the goal, experimental studies on the specific smoke generation coefficient of soft toy samples have been carried out. METHODS. The work uses an experimental standard method for measuring smoke production capacity. Numerical experiments have been carried out to calculate the time of blocking evacuation routes by dangerous fire factors. FINDINGS. The results of measuring the smoke-generating ability of soft toy samples made in China are presented. It has been shown that the smoke generation coefficient of soft toys significantly exceeds the corresponding values for rooms with similar functional purposes. Based on the obtained experimental data and a review of literature sources, a new fire load “soft children's toys” is proposed. The authors present the results of calculating the time of blocking evacuation routes using the analytical solution of the integral model for children's playrooms of various sizes and heights in cases of the proposed fire load, which is most dangerous for rooms of similar functional purposes given in the regulatory documents. It has been found that the condition for safe evacuation during free development of fire is not met. At the same time, loss of visibility is the first dangerous factor of a fire, blocking escape routes, and the highly toxic gas – phosgene – has the shortest blocking time among toxic gases. RESEARCH APPLICATION FIELD. The data obtained can be used to calculate fire risks in children's play rooms of preschool institutions and multifunctional shopping and entertainment centers. CONCLUSIONS. When calculating fire risks in children's play areas, which contain a lot of soft toys, it is necessary to use the proposed fire load “soft children's toys”.

Comprehensive research method for explosive coal dust

The article briefly analyses the explosion and fire hazard properties of coal dust of different dispersions. It is emphasised that many experts working in the field of explosion protection and industrial safety pay insufficient attention to changes in the properties of the dust when reducing its dispersity. It is suggested to develop a new, complex methodology based on the dispersed composition of coal dust. The authors suggest to put methods of special sample preparation and dispersing of samples in two stages as a basis of the complex methodology. To do research with the help of thermal synchronous analysis of the smaller fractions, the authors propose to regrind the coal fraction obtained after the cone crusher in an analytical mill. To exclude adhesion of particles due to the process of static charges accumulation it is suggested to use impactless sieving machine of Retsch company which allows to take out the accumulated charges of static electricity. The coal dust fractions obtained after sieving were sent for granulometric analysis by a dynamic image processing method in CAMSIRE and by an optical microscopic method using a LEICA DM 4000 with image scope colour processing. A simultaneous thermal analysis was performed selectively for fractions smaller than 1000 μm. This was carried out with an STA 449 F3 and NETZSCH Proteus termal analysis application software. The authors consider that the obtained results allow to conclude that it is further expedient to carry out research work in this direction and will make it possible to develop recommendations aimed at prevention of coal dust aerosol explosions.

Prerequisites for applying the risk-based approach to assessing the explosive and fire hazardous properties of underground mining materials

The relevance of the work is due to the introduction of new high-intensity mining technologies underground, the conduct of mining operations at ever greater depths of coal and ore, changes in the explosive properties of the extracted raw materials, as well as incidents and accidents of varying severity occurring at mining facilities. There is an opinion that one of the causes of accidents and emergencies in mines is the inability to take into account both the features of the manifestation of the properties of the rock mass and the change in the explosive properties of minerals. The problem of applying a risk-oriented approach, namely a comprehensive assessment of the risk of accidents, in this case fires and/or explosions, has not been resolved. The applied risk calculation methods are diverse, as a rule, the accuracy of the results is low, and none of them allows taking into account all the identifiable hazards that lead to the occurrence of endogenous and exogenous fires, as well as explosions of hybrid mixtures in the space of mine workings. This article attempts to study in detail the prerequisites for applying a risk-based approach to solving this problem. Theoretical approaches and risk assessment in mines and mines are considered and methods are given that allow in express mode to obtain up-to-date information on the explosive and fire hazardous properties of the extracted raw materials.

Establishing patterns of nitrogen application for fire safety of sunflower grain storage facilities

The issue of using nitrogen to eliminate fires in granaries is related to ventilating the grain mass with nitrogen while it is necessary to take into consideration the change in gas concentration. Therefore, the object of this research was the value of the minimum concentration of nitrogen to eliminate the combustion of sunflower grain. It has been proven that in the process of thermal destruction of sunflower grain, the composition of gaseous products of thermal destruction of sunflower grain contains more than 70 % of combustible gases. Namely: carbon monoxide, over 51 %; hydrogen, about 5.7 %; and hydrocarbons with a total concentration of 13.72 %, which provide fire hazardous properties of organic material. Therefore, it should be noted that the release of the amount of combustible gases during pyrolysis requires a reduction in the amount of oxygen in the gas-air environment to eliminate fire sites. Obviously, such a mechanism for the decomposition of sunflower grain during pyrolysis is a factor in regulating the extinguishing process, due to which the amount of nitrogen to eliminate combustion increases. Comparison of experimental studies on the composition of gaseous products of thermal destruction of sunflower grain and studies to determine the minimum fire extinguishing concentration of nitrogen, at which combustion was stopped, made it possible to justify the use of nitrogen. Based on the study's results on the elimination with nitrogen of fire sites of sunflower grain, the values of the minimum fire extinguishing concentration were revealed at extinguishing, about 33.7 % by volume. At the same time, terminating the combustion of sunflower grain occurs with a decrease in the concentration of oxygen in the gas-air environment of about 14 %. The practical significance is the fact that the results obtained for determining the minimum fire extinguishing concentration of nitrogen make it possible to establish operating conditions for granaries when eliminating fire sites

Establishing regularities in the reduction of flammable properties of wood protected with two-component intumescent varnish

This paper reports the analysis of compositions for fire protection of wood that established that there are not enough data to explain and describe the process of fire protection and, accordingly, the fire-hazardous properties of wood, in order to protect people. The development and research of a set of properties of fire-resistant materials leads to the design of new types of such materials. The object of this study was a fire-protective two-component intumescent varnish for wood. The essence of the research is to determine the indicators of fire danger of wood, fire-protected by coatings, and the impact exerted on them by the formed heat-insulating layer of coke, making it possible to justify the effectiveness of the fire-retardant coating under the influence of temperature. The volume of fire-retardant and hydrophobic coating has been optimized, which ensures the lowest value of loss of mass by fire-protected wood during thermal action. Its lowest value was determined when using flame retardant in the volume of 589 g/m2 and a hydrophobic agent in the volume of 54 g/m2. When determining the combustibility of fire-resistant wood, it was established that the temperature of flue gases during tests was no more than 103 °C, the length of damage to the sample did not exceed 143 mm. At the same time, the weight loss did not exceed 19 g, and the independent burning of wood did not exceed 23 s. In addition, the wood withstood the surface effect of a heat flow of 35 kW/m2, while surface combustion did not occur, and the value of the coefficient of smoke formation was 432 m2/kg during the smoldering of the fire-proof sample. Unlike wood protection with fire-retardant swelling paint, the fireproof wood with two-component varnish, does not change color and refers to low combustibility materials; it is hard to ignite, dose not spread the flame by surface, with moderate smoke-forming ability. The practical significance is the fact that a certificate of conformity was issued based on the reported results. Thus, there are grounds to assert the possibility of directed adjustment of wood fire protection processes by using coatings that can form a protective layer on the surface of the material

Improvement of fire protection of fabrics with intumescent coatings

Based on the analysis of literature sources, the article finds that today it is difficult to imagine the protection of human lives from fire without fire-retardant coatings on textiles. Precisely defined standards allow to determine the requirements for textile materials that have fire protection. It is hardly possible to prevent the inflammation of textiles due to their physical parameters (melting point, flash point). However, it is possible to extend the time for people to escape to start rescue operations by using appropriate fire protection systems or a combination of individual active ingredients. Reducing flammability and developing flammable and combustible materials is one of the main ways to prevent fires and solve the problem of expanding the scope of these materials. Treatment with flame retardants significantly affects the spread of flames, can significantly reduce the ability to smoke and heat. Therefore, research aimed at determining the patterns of fire protection paths used for the manufacture of textiles is relevant. One of such promising areas is the study of the formation of a layer of foam cone in the fire protection of the fabric with intumescent coatings. Experimental studies to determine the fire-hazardous properties of the tectile material revealed the ignition of the untreated sample, while for the fire-retardant – the process of ignition and spread of the flame did not occur. Inhibition of the process of ignition and spread of flame for such a sample is associated with the decomposition of flame retardants under the action of temperature with heat absorption and release of non-combustible gases (nitrogen, carbon dioxide), changing the direction of decomposition towards non-combustible gases and flame retardant coke. This indicates the possibility of transition of the textile material during the processing of the composition to materials that are flammable, do not spread the flame on the surface.

Green and novel approach for enhancing flame retardancy, UV protection and mechanical properties of fabrics utilized in historical textile fabrics conservation

Innovative, green and sustainable multifunctional historical textile coating was developed. The developed coating was constructed from renewable molokhia extract and naturally deposited halloysite nanotubes in presence of chitosan chains. The halloysite nanotubes were wrapped with molokhia extract and then uniformly dispersed in chitosan solution using ultrasonication process and then, coated on linen textile fabrics surface. The thermal stability, surface morphology and structural properties of the treated linen fabrics were investigated using microscopic, spectroscopic and thermogravimetric tools. The mass loadings of molokhia extract and halloysite nanotubes in coating layer are varied. The flammability, mechanical and UV protection properties of the coated and uncoated linen fabrics were evaluated. The flame retardancy properties of developed textile fabrics was significantly improved achieved reduction in rate of burning by 50.2% (40 mm/min) compared to untreated linen fabrics (80.3 mm/min). The tensile strength and elongation properties of developed textile fabrics were improved by 22 and 35%, respectively, compared to untreated linen. Additionally, the ultraviolet rays protective properties of the developed textile fabrics were highly enhanced achieving improvement in ultraviolet protection factor (UPF) by 57%. Moreover, the developed green coating achieved good antibacterial properties for textile fabrics recording 11 mm of clear inhibition zone compared to zero for untreated fabrics. Thus, the smart and green textile coating developed in this study exhibiting a new strategy for historical textile conservation against harmful UV rays, failure in tensile strength and fire hazard properties.

MULTIFACTOR METHOD FOR EVALUATING THE EFFECTIVENESS OF WOOD FIRE PROTECTION

The problem of using fire-resistant materials for wooden building structures is to ensure their stability and durability when operating in atmospheric conditions, when it is possible to wash out flame retardants and lose fire resistance. The purpose of this study is to identify the indicators of fire hazard of wood, fire-proof coatings and the effect on them of the heat-insulating layer of coke formed, which allow justifying the effectiveness of the fire-resistant coating under the influence of temperature. The study used a comprehensive research method, which consisted in determining the fire-hazardous properties of fire-proof wood and methods for determining the operational properties of wood fire protection. It was found that upon applying a coating based on alkyd-polyurenitan varnish, due to the polymer film formed on the wood surface, the permeability of flame-retardant components decreases. Tests of fire-hazardous features of wood protection from fire have shown that the coating swells under the influence of heat flow and contributes to a significant heat-insulating layer of coke, which prevents oxygen from reaching the wood and, accordingly, hot temperature, which can ignite the wood. In general, the effectiveness of wood protection from fire shown that wood protected from fire belongs to hard-to-burn materials that slowly spread flames on a surface with low smoke-forming ability. The practical value of this paper lies in the fact that the obtained method for identifying the features of wood protection from fire, comprises determining both atmospheric and thermal properties, and allows establishing the operating conditions of fire protection and the use of products and building structures made of wood of a wide range of uses

MOF-derived 3D petal-like CoNi-LDH array cooperates with MXene to effectively inhibit fire and toxic smoke hazards of FPUF

The toxic smoke produced by the combustion of flexible polyurethane foam (FPUF) may not only caused casualties, but also polluted the environment. Here, double metal hydroxide derived from ZIF-67 (MOF-LDH) modified Ti3C2TX (Ti3C2TX@MOF-LDH) was innovatively designed to solve the serious smoke and fire hazards of FPUF. The FPUF nanocomposite containing 6 wt% Ti3C2Tx@MOF-LDH achieved a 16.1% reduction in total smoke production (TSP) along with 22.2% reduction in peak smoke production rate (PSPR), which greatly reduced the hazard of smoke. At the same time, toxic gases, such as carbon monoxide (CO), carbon dioxide (CO2), and aromatic compounds, showed the same reduction pattern. In addition, the heat release of FPUF nanomaterials was also suppressed. In particular, the FPUF/Ti3C2Tx@MOF-LDH 3.0 achieved 110.4% and 76.1% increase in compressive strength and tensile strength, respectively, confirming the effective mechanical enhancement. Therefore, this work provided a new reference for the preparation of high-performance FPUF nanocomposites with low smoke, low fire hazard and excellent mechanical properties.

Methodological approach to the need to assess the explosion and fire hazard properties of sulfide-containing polymetallic ores

Methodological approach to the need to assess the explosion and fire hazard properties of sulfide-containing polymetallic ores

Особенности пожароопасных свойств семян подсолнечника, способов их хранения и тушения

The physicochemical and fire-hazardous properties of sunflower seeds are considered, the peculiarities in the manifestation of the propensity of the product in violation of storage conditions and regimes (high humidity, temperature, high weeds, increased acid number of raw materials and, as a consequence, the manifestation of the vital activity of microorganisms and insects) to self-heating and spontaneous combustion are revealed. Under favorable conditions of heat accumulation and air inflow, spontaneous combustion can turn into open. This is especially typical for the processes of thermal and thermo-oxidative destruction of sunflower seeds enriched with oil, and because of the high well content, also with oxygen in the air. In buildings of sunflower floor storage, fire extinguishing when detected by fire alarm systems is carried out with the use of water and water-based means. The most acceptable and effective way to suppress the burning of vegetable raw materials and compound feeds, and to safely unload it from granaries is the combined method.

Effects of Basalt and Carbon Fillers on Fire Hazard, Thermal, and Mechanical Properties of EPDM Rubber Composites.

Due to growing restrictions on the use of halogenated flame retardant compounds, there is great research interest in the development of fillers that do not emit toxic compounds during thermal decomposition. Polymeric composite materials with reduced flammability are increasingly in demand. Here, we demonstrate that unmodified graphene and carbon nanotubes as well as basalt fibers or flakes can act as effective flame retardants in polymer composites. We also investigate the effects of mixtures of these carbon and mineral fillers on the thermal, mechanical, and rheological properties of EPDM rubber composites. The thermal properties of the EPDM vulcanizates were analyzed using the thermogravimetric method. Flammability was determined by pyrolysis combustion flow calorimetry (PCFC) and cone calorimetry.

Thermal Properties of Fullerene С<sub>56</sub>

The behavior of С56 fullerene when heated in a nitrogen atmosphere at a pressure of 105 Pa was studied using computer thermodynamic modeling. The modeling consisted in a complete thermodynamic analysis of the system using the TERRA software package, which is one of the most developed and efficient ones that implements such thermodynamic calculations. Experiment temperature ranges are from 273 to 3373 К. Based on the calculated data, a graph of the carbon balance in the С56-N2 system was constructed, the ongoing physicochemical processes were described, divided into four classes: sublimation, dissociation in the gas phase, chemical reactions occurring in the gas phase, dissociation and chemical reaction in the gas phase. Temperature intervals of reactions are identified. The equilibrium constants of the reactions are calculated and described, as well as the coefficients of these constants are found using the least squares method. The temperature interval of thermal stability of the condensed C56 fullerene and C56 vapors is defined. This work is one of the series of works on the properties of nanoparticles, in the future it is planned to study the thermal properties of higher fullerenes. The data obtained can be used to determine the explosive and fire hazardous properties of fullerenes as a dispersed solid.