Исследование условий теплового самовозгорания тяжелых углеводородов (на примере битумов) на развитой поверхности волокнистой негорючей теплоизоляции

Unique spatial methane distribution caused by spontaneous coal combustion in coal mine goafs: An experimental study

In this study, glass wool waste was utilized by means of alkali-activation with blast furnace slag. Reaction kinetics, workability, mechanical properties and autogenous shrinkage of alkali-activated slag and glass wool were comprehensively studied. Results indicated an optimal modulus (SiO2/Na2O) of the activator related to a long enough setting time and a high reaction degree of alkali-activated slag paste. The incorporation of glass wool as partial slag replacement did not necessarily lead to degradation in the performance of the pastes. While the compressive strength was always lower when glass wool was incorporated in the mixture, the flexural strength and workability could be improved with proper glass wool dosages. Autogenous shrinkage of blended pastes was always lower compared to the the mixture without glass wool. The results in this paper suggest that waste glass wool can be used as a precursor in slag-based alkali-activated system, resulting in improvements in the early-age properties of the paste such as a prolonged setting time and reduced shrinkage.

Spontaneous combustion is one of the most serious problems to mine safety and production in the global coal industry. It is considered to be the trigger for fires and explosions in underground coal mines especially for gassy mines. Such thermal events are not easily detectable since they normally occur in inaccessible gob and sealed area. It is also difficult to find the most likely hot point accurately. Admittedly, determination of the propensity for spontaneous combustion before mining activity should be a necessary step in the design of a mine and ventilation plan. However, due to the complexity of the chemical and physical properties of coal, spontaneous combustion has not been fully understood.;Many methods and techniques have been developed for studying self-heating of coal. Each of the methods has its unique characteristics and index for assessing the propensity of self-ignition. However, all the reasonable candidate factors causing spontaneous combustion could not be examined thoroughly by any single method. Accountable relationships among the propensity indices of different methods should be established. The certainty for assessing the propensity of spontaneous combustion will be greatly improved by using the combination of various methods. On the other hand, spontaneous combustion is affected by many factors. According to a proximate analysis of coal, it is believed that sulfur and volatile matter in coal are the main intrinsic factors that cause the self-heating of coal. Their oxidation at lower temperatures than that of fixed carbon to initiate coal's self-heating should be quantified.;In order for better understanding spontaneous combustion behavior, the following research has been done in this dissertation:;• Establishment of a coal spontaneous combustion testing facility that features adiabatic self-heating, thermogravimetric analyzer (TGA) and USBM self-heating temperature methods in the mine ventilation laboratory at West Virginia University.;• Correlation of U.S. coal rank and propensity for spontaneous combustion has been studied by classifying coal rank quantitatively. This quantified rank system provides a schematic view that reflects the relationship between rank and self-heating temperature of coal. As such, it can be used to serve as a quick estimate of self-heating potential of U.S. coals and as a cost effective way for initial risk assessment for any new mine development.;• Based on the law of energy conservation, a mathematical model has been developed to quantify the self-heating rate of coal and assist the adiabatic self-heating test when the testing period becomes impractically long. Then improvements have been made to the

Effect of cellulose fibre based insulation on thermal performance of buildings

Nowadays, the usage of thermal insulation materials is widespread not only in the building sector but also in the vehicle industry. The application of fibrous or loose-fill insulation materials like glass wool or mineral wool as well as aerogel is well known. Aerogel-based materials are among the best solid materials for thermal insulation available today; they are prepared through a sol–gel process. For building walls, the glass-fiber-enhanced types are the frequently used ones. They are prepared by adding the liquid–solid solution to the fibrous batting, which is called a sol–gel process. In the present paper, the changes in the most important building physical properties of aerogel blankets after thermal annealing are presented. The samples were subjected to isochronal heat treatments from 70 to 210 °C for 24 h. The changes in the thermal conductivity were followed by Holometrix Lambda heat flow meter, and differential scanning calorimetry results were also recorded. From the measured values, together with the densities, the most important thermal properties were calculated, such as thermal resistance, diffusivity, effusivity (heat absorption), and thermal inertia. In this paper, we attempt to clarify the role played by thermal annealing in the transient thermal properties of aerogel materials. Besides presenting the measurement results, a theoretical background is given. The investigations of not only the steady-state but also the transient thermal parameters of the materials are momentous at the design stage.

Globally, the building sector consumes approximately 60% of the total energy usage, while the energy consumption of residential buildings lies between 20% to 40%. The majority of this energy is operational energy, which comes mainly from the heating and cooling of houses. Innovative and cost-effective insulation materials have the potential to reduce the operational energy requirements and can therefore make the buildings more energy efficient. In this study, three commonly available insulation materials were experimentally evaluated for a case study of residential buildings, located in a cold region of Pakistan. Glass wool, extruded polystyrene, and polyethylene were used, as insulation materials, for monitoring the case study building performance. Thermal data were collected for 21 days in the year 2019 using a Testo Saveries System and were then used for analyzing the thermal performance of each of the three types of insulation materials. Other relevant data including the cost of insulation materials, thickness, ease of application, design life, and fire resistance of the selected insulation materials were obtained for broader (based on the scorecard) analysis based on a multi-weighted decision model. It was concluded that Polyethylene was the most economical insulation material amongst the others, which also showed the best thermal performance. Polyethylene was also found to be the best insulation material for the case study building based on a multi-weighted decision model and, hence, is recommended for application in buildings around cold regions of Pakistan.

This paper first summarises the data from the US and European epidemiological studies upon which many claims about the carcinogenicity of insulation wools (rock wool, slag wool, and glass wool) have been made. Emphasis has been given to the conclusions of the researchers rather than the conclusions of reviewers who have pooled the data from both continents. The results of the most recently published epidemiological study of crocidolite miners and millers (the Wittenoom cohort) have then been summarised and compared with the man-made mineral fibre studies.

Due to extremely low thermal conductivity, high modulus, high toughness, light weight and non-combustible property, ultrafine glass wool can be widely used as glass fiber reinforcements in composites, thermal insulation materials, acoustic insulation materials, engineering materials, construction, infrastructure and environmental protection projects and so on. In particular, as a insulation material, glass wool exhibits unique advantages. The predominant process of glass wool is centrifugal blowing process. This paper describes a study of the relationship between the diameter of ultrafine glass fiber and thermal conductivity. The thermal conductivity of ultrafine glass wool decreases with the decrease of average diameter.

The study aimed to characterize the mineral wools obtained from wastes of the cutting step of marble and granite, in order to evaluate the possibility of their use on an industrial scale. Mixtures of marble and/or granite wastes were prepared in order to reach the chemical composition of rock and glass wools. The batches were melted in an electric arc furnace in laboratory scale at 1450oC and casted with water, in order to obtain a higher cooling rate. Characterization work was performed in batches that formed vitreous material, and with superior incorporation of the residues: 11.7% and 14.6% of marble waste with glass wool and rock wool, respectively; 78.3% and 91.6% of an association of marble and granite wastes with glass wool and rock wool, respectively. Computational thermodynamics was used in order to obtain the main phases at 800oC and determine the liquid and solid content at 1400, 1450 and 1500oC. In addition, the materials obtained were characterized via chemical analysis using X-ray fluorescence, DTA, X-ray diffraction and SEM. The results indicate that the marble and granite waste are composed mainly of CaO (34.7 wt.%) and SiO2 (66.3 wt.%), respectively. An amorphous crystalline structure was obtained in all tests, indicating that this material can be used as an insulation material. The crystallization temperatures were determined around 800oC.

Investigation of usability of boron doped sheep wool as insulation material and comparison with existing insulation materials

The article is devoted to the study of the causes and conditions of spontaneous com- bustion of sulphide ores, which may result in endogenous fires that complicate mining operations in mines, causing enormous material damage to the national economy, and often also leading to human casualties. There are several sulphide-polymetallic deposits in Azerbaijan, the reserves of which were approved back in the days of the USSR. Of these, the Filizchay deposit is the most unique in terms of its reserves and ore composition. The development of other deposits adjacent to the Filizchay deposit, separately, is inexpedient because of their small reserves. However, the development of sulphide-polymetallic deposits in Azerbaijan is complicated by the revealed tendency of industrial types of ores to oxidation and spontaneous combustion. In this regard, there was a need for a special study of the chemical activity of sulphide ores and the phenomena accompanying oxidative processes, taking into account the natural features of the deposits in order to obtain the initial parameters necessary for scientifically based technological solutions for their development. Sulphide ores of sulphide -polymetallic deposits of Azerbaijan significantly differ in material composition, conditions of occurrence and mining technical features of their development from the listed deposits, the issues of spontaneous combustion of which have been studied for a long time. Until now, there are no general criteria for assessing the fire hazard of sulphide ores, suitable for any deposit, since the conditions for the occurrence of underground fires at different deposits are different. It is this circumstance that makes it necessary to conduct special studies for each deposit separately. Therefore, the need for a special study of this problem on the example of the conditions of sulphide-polymetallic deposits in Azerbaijan, which are prone to oxidation and spontaneous combustion, is of great importance. Identification of causes and factors affecting spontaneous combustion of sulphide ores, classification of sulphide-polymetallic deposits of Azerbaijan according to the degree of their tendency to spontaneous combustion by analyzing the collected materials, as well as by the results of studies to determine the oxidative activity of sulphide ores. The article presents the results of experimental studies to determine the oxidative activity and spontaneous combustion of sulphide ores of the Katsdag, Filizchay and Katekh deposits, carried out in laboratory conditions by the method of Institute of Mining named after. A.A. Skochinsky, the basis of which is the determination of the oxygen absorption rate constant. It is known that the susceptibility of ore to spontaneous combustion is determined by its oxidizability at low temperatures and depends on a large number of factors. In this regard, the dependence of the total amount of oxygen absorbed by sulphide ores on time has been studied, it has been established that the rate of oxygen absorption by sulphide ores is long-live and slowly fading, but incessant. On the basis of extensive experimental material, a classification of sulphide ores of Azerbaijan according to the degree of tendency to spontaneous combustion according to low-tempera-ture oxidation is proposed, since it is this that forms the basis of the spontaneous combustion process. The classification is also based on differences in textural and structural features and mineralogical composition of ores. Of great interest is also the influence of the size of the free reacting surface of the ore on the oxidation process. Analysis of ore samples shows that for their spontaneous combustion, the most dangerous are its coarse fractions than the dust. The results of the conducted studies allow a scientifically sound approach to planning the sequence of development and designing mines.

As composite materials have been used for marine structures such as boats, ships, offshore structures, etc., the effect of FSI should be understood.In particular, FSI effect is expected to be significant for polymer composites because the water density is very comparable to the composites' densities.For example, the density of a carbon composite is approximately 50% greater than the water density.Sandwich composites consisting of very low densities of core materials have lower densities than that of water.As a result, the hydrodynamic mass associated with FSI would be very critical to composite structures under water.The growing use of composites in ship masts, superstructures, deck grates, piping, ducting, rudders, propellers, stacks, and various submarine structures requires extensive modeling and testing to help designers, builders and operators better understand composite response [Mouritz, et al., 2001].These materials are subjected to a wide spectrum of loads during manufacturing and service life.Dynamic loadings, in particular, impact type event, represent a serious design concern for use of composite.Composite structures are more susceptible to impact damage than similar metallic structures which are more ductile in nature and can absorb typically large amounts of energy without failure.Furthermore, the damage in composites from impact can go undetected even when the mechanical properties may be drastically reduced from an impact.For these reasons, numerous experimental and analytical studies have been conducted to study the dynamic response of composites subjected to impact loading [Abrate, 1994;Aslan, et al., 2003;Kwon & Wojcik, 1998].According to the review of past works, most of the research effort has been focused on low velocity impact damage, specifically, the damage predictions, and the evaluation and prediction of residual properties of damaged laminates.All of the research completed thus far has focused on damage in composites under impact loading in dry environments to support development of composites in aircraft structures.As far as dynamic response of structures under water is concerned, a great deal amount of analytical and experimental studies have been conducted on the effect of fluid force on the natural frequencies, damping ratios and mode shapes of vibrating structures in contact with fluid.This is commonly known as the Fluid Structure Interaction (FSI) problem.FSI investigations have supported many problems in submarine signaling, offshore oil structure stability, and ship structure vibrations.Through these studies, many numerical and analytical methods have been developed in order to predict the added mass and the www.intechopen.com Advances in Composites Materials -Ecodesign and Analysis 338resulting changes in natural frequency of a structure in contact with fluid.It has been determined and widely proven that the effect of fluid surrounding a structure decreases the natural frequency of a structure due to the increase in total kinetic energy of the vibrating structure and fluid from the addition of kinetic energy of the fluid.This effect can be interpreted as an added mass to the vibrating structure in the analysis of the dynamic response.Essentially as the structure vibrates, its mass is increased by the mass of the vibrating fluid with which it is in contact, consequently decreasing its natural frequency.Studies of fluid structure interaction and the added mass effect, also known as virtual mass effect, hydrodynamic mass, and hydroelastic vibration of structures, started with Lamb [Lamb, 1921] who calculated the first bending mode of a submerged circular plate.In response to a problem of submarine signaling, Lamb investigated the vibrations of a thin elastic circular plate in contact with water.In his investigation he discovered that the natural frequencies for structures in contact with fluid are lower than the frequencies in air, based on the assumption that the modes shapes are virtually the same in water as in a vacuum.The resonant frequency was determined using Rayleigh's method.Lamb's theortical results were verified experimentally [Powell & Roberts, 1923].Much later, more research was conducted for measuing and calculating natural frequencies of free vibartions of beams and plates under water [Lindholm, et al., 1965; Fu & price, 1979;Kwak, 1996].Another branch of FSI studies is underwater explosion.Both experimental and numerical studies have been conducted for metallic structures [

For sewage pump that various foreign substance is flowed into, anti-clogging performance is a factor as important as pump efficiency in order to avoid clogging trouble by foreign substance. Many investigations about pump inner flow and pump efficiency estimation have been carried out conventionally in order to realize coexistence with anti-clogging performance and pump performance. And these results have been reflected in construction of the running water section design method. As a index of anti-clogging performance, "impeller passage diameter" which is diameter of spherical solid that can pass through the pump is used widely. And there are various type of the sewage pump which have large impeller passage diameter. However real cause of clog is not a solid, and it is fibrous material such as towel and clothes, vinyl and paper diaper. In most case these material accumulate in the pump, so that clog is occurred. In this study, for the purpose of quantification of anti-clogging performance against fibrous materials, the factor that affect to clogging of pump was investigated by pump model test using a string. The test is done based on Taguchi method. In this test, type of the pump model, diameter of the string, material of the string, length of the string and flow rate are selected for the factor, and the effect that they have on the clogging of the pump was investigated. As a result of this test, it was made clear that length of the string has a strong influence on the clogging of the pump. And from the result of this test, evaluation method of anti-clogging performance of the pump against fibrous material by using string was considered. According to the result of above test based on Taguchi method, it was assumed that quantification of anti-clogging performance against fibrous materials is possible by flowing plural strings into the pump and calculating the probability of passing. Plurality sewage pumps of different types were evaluated based on this assumption. And It was confirmed that it is possible to compare anti clogging performance of the pump against fibrous materials quantitatively. And the specification of the string was selected according to the result of the test based on Taguchi method. By this method, one of the evaluation method on anti-clogging performance against fibrous materials was established.

In 2001, the International Agency for Research on Cancer (IARC) assembled a group of 18 international experts on the health effects of fibers. Their task was to review the available science on the health aspects of glass, rock, and slag wool fibers. The group of experts determined that glass, rock, and slag wool insulation fibers should be removed from the IARC list of possible carcinogens. That decision was based fundamentally on the development of new science that has led to an understanding of those properties of fibers which affect their potential biological activity. This presentation will provide both an overview of this new science and provide guidelines to assure the safety of fiber-based materials used in acoustic and noise-control applications.

Thermal insulation improves the strength and longevity of buildings by reducing energy consumption, and as a related result, improved energy use. The selection of insulation material is governed by important parameters, including the average outdoor air temperature, the thermal conductivity of the buildings and the cost of the insulation material. Increases in the thickness of the insulation material will gradually decrease the energy consumption for heating; however, the insulation thickness has an optimum value that minimises the total investment cost, and determination of this optimum value is critical for economic analysis. In this paper, a life-cycle cost analysis is presented to show the optimum insulation thickness, energy savings over a lifetime of 15 years and payback periods for six different fuels and insulation materials for four cities in Turkey selected from climate regions identified by the Turkish Thermal Insulation Standard (TS 825). Mugla (1st region), Kocaeli (2nd region), Ankara (3rd region) and Ardahan (4th region) were selected for analysis of a sandwich-type wall constructed from the following six insulation materials: extruded polystyrene, expanded polystyrene, glass wool, rock wool, polyisocyanurate and polyurethane. The calculations were also made on the basis of six different fuels, such as motorin, natural gas, propane (LPG), electricity, coal (imported), and fuel-oil No. 4. As a consequence, results demonstated that the optimum insulation thickness vary between 2.8 cm and 45.1 cm, with energy savings between 16.4 ₺ /m 2 and 479 ₺ /m 2 , and payback periods fluctuating between 0.078 and 0.860 years, depending on the city, the insulation material, and the cost of fuel.