scholarly journals Assessment of Heating and Cooling of a Spontaneous Fire Source in Coal Deposits—Effect of Coal Grain Size

Minerals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 907
Author(s):  
Marek Więckowski ◽  
Natalia Howaniec ◽  
Adam Smoliński
Keyword(s):  
Carbon Monoxide ◽  
Hazard Assessment ◽  
Fire Hazard ◽  
Temperature Drop ◽  
Coal Bed ◽  
Coal Deposit ◽  
Fire Source ◽  
Heating And Cooling ◽  
Spontaneous Fire ◽  
The Impact

Fire hazard assessment in coal mines is performed on the basis of concentrations of particular gases emitted from the heating coal deposit, but more precise criteria and indicators are needed to assess fire hazard properly—both during the temperature rise phase and in the coal bed cooling phase. In the paper the impact of coal grinding on hazard assessment of spontaneous fire development in the coal deposit during heating and cooling the fire source was analyzed. The intensity of desorption of ethane, ethylene, propane, propylene, acetylene, carbon monoxide and hydrogen is the resultant of temperature and grinding of coal samples. The results proved that the ratio of concentrations emitted by standard versus coarsely crushed coal for each of the gases, changed both in the growth phase as well as in the temperature drop phase. It was found that as the temperature rose, the effect of coal grinding on the release of ethane, ethylene, propane, propylene and carbon monoxide decreased. The greatest effect of coal grinding was observed in the case of ethane and propane, while the lowest in the case of hydrogen and carbon monoxide.

scholarly journals Changes in the Distribution of Temperature in a Coal Deposit and the Composition of Gases Emitted during Its Heating and Cooling

2018 ◽  
Vol 10 (10) ◽  
pp. 3587 ◽  
Author(s):  
Marek Więckowski ◽  
Natalia Howaniec ◽  
Eugene Postnikov ◽  
Mirosław Chorążewski ◽  
Adam Smoliński
Keyword(s):  
Fire Hazard ◽  
Hot Spot ◽  
Measuring System ◽  
Hard Coal ◽  
Coal Deposit ◽  
Hazard Indices ◽  
Heating And Cooling ◽  
Cooling Phase ◽  
Percentage Share ◽  
The Given

This article presents the results of tests conducted on a measuring system for monitoring changes in the distribution of temperature in a coal deposit during the heating and cooling phases, and their correlation with the analysis of the concentration of gases. The tests were conducted on five samples of hard coal collected in deposits mined in Poland. Measurements of the changes in temperature and changes in gas concentration were conducted from the temperature of 35 to 300 °C, for the heating phase, and from 300 to 35 °C, for the cooling phase. The percentage share of coal of given temperatures was calculated. When comparing the percentage share for the same temperature in the hot spot, for the heating and cooling phase, significant differences in the distribution of the given percentages were observed. Changes in gas concentrations during heating and cooling were analyzed and the dynamics of changes in gas concentrations were determined for the coals tested. Changes in the values of fire hazard indices were analyzed. There were significant differences in the concentration of gases and the values of fire hazard indices between the heating and the cooling phase. The application of different criteria to assess coal during heating and cooling was proposed.

scholarly journals Effect of flow rates of gases flowing through a coal bed during coal heating and cooling on concentrations of gases emitted and fire hazard assessment

2019 ◽  
Vol 7 (1) ◽  
pp. 107-121 ◽  
Author(s):  
Marek Więckowski ◽  
Natalia Howaniec ◽  
Adam Smoliński
Keyword(s):  
Fire Hazard ◽  
The Self ◽  
Coal Bed ◽  
Flow Rates ◽  
Coal Beds ◽  
Heating And Cooling ◽  
Heating Phase ◽  
Two Samples ◽  
Cooling Phase ◽  
Phase Temperature

AbstractThe flow velocity of gases in gobs directly influences the kinetics and intensity of gaseous components release during heating and cooling of coal. The assessment of fire hazard is performed on the basis of concentrations of particular gases in a mine air. These concentrations differ in coal heating and cooling phase which was proven in the study. This paper presented the results of the experimental study on temperature distribution in a simulated coal bed in heating (50–250 °C) and cooling (250–35 °C) phases as well as its correlation to variations in concentration of gases released in these phases and flow rates of gases flowing through the coal bed. The research was performed on twenty-two samples of bituminous coals acquired from various coal beds of Polish coal mines. Considerable differences were observed between heating and cooling phases in terms of the concentrations of gases taken into account in calculations of self-combustion index. In the heating phase temperature increase resulted in the decrease of concentrations ratios of ethane, ethylene, propane, propylene and acetylene, while in the cooling phase these ratios increased systemically. The effect of air (in heating phase) and nitrogen (in cooling phase) flow rate on the self-ignition index CO/CO2 was also determined.

scholarly journals Deterministic approach for multiple-source tsunami hazard assessment for Sines, Portugal

2015 ◽  
Vol 15 (11) ◽  
pp. 2557-2568 ◽  
Author(s):  
M. Wronna ◽  
R. Omira ◽  
M. A. Baptista
Keyword(s):  
Sea Level ◽  
Wave Height ◽  
Hazard Assessment ◽  
Test Site ◽  
Tsunami Hazard ◽  
Deterministic Approach ◽  
Flow Depth ◽  
Mean Sea Level ◽  
Tsunami Hazard Assessment ◽  
The Impact

Abstract. In this paper, we present a deterministic approach to tsunami hazard assessment for the city and harbour of Sines, Portugal, one of the test sites of project ASTARTE (Assessment, STrategy And Risk Reduction for Tsunamis in Europe). Sines has one of the most important deep-water ports, which has oil-bearing, petrochemical, liquid-bulk, coal, and container terminals. The port and its industrial infrastructures face the ocean southwest towards the main seismogenic sources. This work considers two different seismic zones: the Southwest Iberian Margin and the Gloria Fault. Within these two regions, we selected a total of six scenarios to assess the tsunami impact at the test site. The tsunami simulations are computed using NSWING, a Non-linear Shallow Water model wIth Nested Grids. In this study, the static effect of tides is analysed for three different tidal stages: MLLW (mean lower low water), MSL (mean sea level), and MHHW (mean higher high water). For each scenario, the tsunami hazard is described by maximum values of wave height, flow depth, drawback, maximum inundation area and run-up. Synthetic waveforms are computed at virtual tide gauges at specific locations outside and inside the harbour. The final results describe the impact at the Sines test site considering the single scenarios at mean sea level, the aggregate scenario, and the influence of the tide on the aggregate scenario. The results confirm the composite source of Horseshoe and Marques de Pombal faults as the worst-case scenario, with wave heights of over 10 m, which reach the coast approximately 22 min after the rupture. It dominates the aggregate scenario by about 60 % of the impact area at the test site, considering maximum wave height and maximum flow depth. The HSMPF scenario inundates a total area of 3.5 km2.

scholarly journals Damage Evolution of Granodiorite after Heating and Cooling Treatments

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 779
Author(s):  
Mohamed Gomah ◽  
Guichen Li ◽  
Salah Bader ◽  
Mohamed Elkarmoty ◽  
Mohamed Ismael
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Failure Mode ◽  
Physical And Mechanical Properties ◽  
P Wave ◽  
Physical Parameters ◽  
Slow Cooling ◽  
Heating And Cooling ◽  
Natural Rock ◽  
The Impact

The awareness of the impact of high temperatures on rock properties is essential to the design of deep geotechnical applications. The purpose of this research is to assess the influence of heating and cooling treatments on the physical and mechanical properties of Egyptian granodiorite as a degrading factor. The samples were heated to various temperatures (200, 400, 600, and 800 °C) and then cooled at different rates, either slowly cooled in the oven and air or quickly cooled in water. The porosity, water absorption, P-wave velocity, tensile strength, failure mode, and associated microstructural alterations due to thermal effect have been studied. The study revealed that the granodiorite has a slight drop in tensile strength, up to 400 °C, for slow cooling routes and that most of the physical attributes are comparable to natural rock. Despite this, granodiorite thermal deterioration is substantially higher for quick cooling than for slow cooling. Between 400:600 °C is ‘the transitional stage’, where the physical and mechanical characteristics degraded exponentially for all cooling pathways. Independent of the cooling method, the granodiorite showed a ductile failure mode associated with reduced peak tensile strengths. Additionally, the microstructure altered from predominantly intergranular cracking to more trans-granular cracking at 600 °C. The integrity of the granodiorite structure was compromised at 800 °C, the physical parameters deteriorated, and the rock tensile strength was negligible. In this research, the temperatures of 400, 600, and 800 °C were remarked to be typical of three divergent phases of granodiorite mechanical and physical properties evolution. Furthermore, 400 °C could be considered as the threshold limit for Egyptian granodiorite physical and mechanical properties for typical thermal underground applications.

Comparison of a preferred versus non-preferred waterpipe tobacco flavour: subjective experience, smoking behaviour and toxicant exposure

2017 ◽  
Vol 27 (3) ◽  
pp. 319-324 ◽  
Author(s):  
Eleanor L Leavens ◽  
Leslie M Driskill ◽  
Neil Molina ◽  
Thomas Eissenberg ◽  
Alan Shihadeh ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
Subjective Experience ◽  
Smoking Behaviour ◽  
Toxicant Exposure ◽  
P Values ◽  
Smoking Topography ◽  
Exhaled Carbon Monoxide ◽  
Continued Use ◽  
The Impact ◽  
Survey Questionnaires

IntroductionOne possible reason for the rapid proliferation of waterpipe (WP) smoking is the pervasive use of flavoured WP tobacco. To begin to understand the impact of WP tobacco flavours, the current study examined the impact of a preferred WP tobacco flavour compared with a non-preferred tobacco flavoured control on user’s smoking behaviour, toxicant exposure and subjective smoking experience.MethodThirty-six current WP smokers completed two, 45-minute ad libitum smoking sessions (preferred flavour vs non-preferred tobacco flavour control) in a randomised cross-over design. Participants completed survey questionnaires assessing subjective smoking experience, exhaled carbon monoxide (eCO) testing, and provided blood samples for monitoring plasma nicotine. WP smoking topography was measured continuously throughout the smoking session.ResultsWhile participants reported an enhanced subjective smoking experience including greater interest in continued use, greater pleasure derived from smoking, increased liking and enjoyment, and willingness to continue use after smoking their preferred WP tobacco flavour (p values <0.05), no significant differences were observed in nicotine and carbon monoxide boost between flavour preparations. Greater average puff volume (p=0.018) was observed during the non-preferred flavour session. While not significant, measures of flow rate, interpuff interval (IPI), and total number of puffs were trending towards significance (p values <0.10), with decreased IPI and greater total number of puffs during the preferred flavour session.DiscussionThe current study is the first to examine flavours in WP smoking by measuring preferred versus control preparations to understand the impact on subjective experience, smoking behaviour and toxicant exposure. The pattern of results suggests that even this relatively minor manipulation resulted in significant changes in subjective experience. These results indicate a possible need for regulations restricting flavours in WP tobacco as with combustible cigarettes.

scholarly journals Impact hazard monitoring: theory and implementation

2015 ◽  
Vol 10 (S318) ◽  
pp. 221-230
Author(s):  
D. Farnocchia
Keyword(s):  
Hazard Assessment ◽  
Yarkovsky Effect ◽  
Monte Carlo Algorithms ◽  
Impact Monitoring ◽  
Successful Technique ◽  
Low Probability ◽  
Computationally Intensive ◽  
Orbit Estimation ◽  
Near Earth Asteroids ◽  
The Impact

AbstractWe review the most standard impact monitoring techniques. Linear methods are the fastest approach but their applicability regime is limited because of the chaotic dynamics of near-Earth asteroids. Among nonlinear methods, Monte Carlo algorithms are the most reliable ones but also most computationally intensive and so unpractical for routine impact monitoring. In the last 15 years, the Line of Variations method has been the most successful technique thanks to its computational efficiency and capability of detecting low probability events deep in the nonlinear regime. We also present some more recent techniques developed to deal with the new challenges arising in the impact hazard assessment problem. In particular, we describe keyhole maps as a tool to go beyond strongly scattering encounters and how to account for nongravitational perturbations, especially the Yarkovsky effect, when their contribution is the main source of prediction uncertainty. Finally, we discuss systematic ranging to deal with the short-term hazard assessment problem for newly discovered asteroids, when only a short observed arc is available thus leading to severe degeneracies in the orbit estimation process.

The impact of technology on architecture in Iran with focus on saving in energy consumption

2015 ◽  
Vol 16 (SE) ◽  
pp. 97-103
Author(s):  
Allah Bakhsh Kavoosi ◽  
Shahin Heidari ◽  
Hamed Mazaherian
Keyword(s):  
Energy Consumption ◽  
Energy Demand ◽  
Industrial Revolution ◽  
Demand Prediction ◽  
Interior Spaces ◽  
Heating And Cooling ◽  
Impact Of Technology ◽  
Contemporary Architecture ◽  
The Impact ◽  
The Given

Growth and development of technology caused enormous transformation and change in the world after Industrial Revolution. The contemporary human has prepared the platform for their realization in many activities that the humans were unable to do it in the past time and struck the dream of their realization in their mind so that today doing many of those activities have been apparently practical by human. This accelerating growth accompanied with consuming a lot of energy where with respect to restriction of the given existing resources, it created energy crises. On the other hand, along with growth in industry and requirement for manpower and immigration from village to city and basic architectural changes in houses, which have emerged due to change in social structure it has led to change in lifestyle and type and quantity of consuming energy in contemporary architecture. Inter alia, with increase in human’s capability, cooling and heating and acoustic and lighting technologies were also changed in architecture and using mechanical system was replaced by traditional systems. Application of modern systems, which resulted from growth of industry and development of technology and it unfortunately, caused further manipulation in nature and destruction of it by human in addition to improving capability and potential of human’s creativity. With respect to growth of population and further need for housing and tendency to the dependent heating and cooling systems to them in this article we may notice that the housing is assumed as the greatest consumer of energy to create balance among the exterior and interior spaces in line with creating welfare conditions for heating and cooling and lighting. The tables of energy demand prediction in Iran show that these costs and energy consumption will be dubbed with energy control smart management in architecture.

EFFECT OF CARBON MONOXIDE ON THE RATE OF EXCRETION OF ETHANOL BY KIDNEYS

2021 ◽  
pp. 15-21
Author(s):  
Beschasnyi S.P. ◽  
Lysenko E.M. ◽  
Hasiuk O.M. ◽  
Erlish О.О.
Keyword(s):  
Carbon Monoxide ◽  
The Body ◽  
Gas Liquid Chromatography ◽  
Older Individuals ◽  
Chromatography Method ◽  
Co Intoxication ◽  
Blood And Urine Samples ◽  
Liquid Chromatography Method ◽  
High Level ◽  
The Impact

Carbon monoxide is a toxic gas that is colourless, odourless, and has the potential to cause momentaryhypoxia by bonding with heme-inspired proteins. Because of these properties, it causes the highest number of toxications. Due to its properties, this gas causes damage to the nervous and cardiovascular system. The development of anoxia is associated with the impact on the system of oxidative phosphorylation in mitochondria and the development of oxidative stress in the body. The body produces a small amount of carbon monoxide as a result of erythrocyte breakdown. Picomolar concentrations of carbon monoxide even have anti-inflammatory, antiapoptotic,cytoprotective and antiproliferative properties. Kidney is one of the first organs,that responds to the occurrence of hypoxia, are responsible for the removal of products of metabolism and toxicants, including ethanol. For the study, the blood and urine samples were taken from patients with acute intoxication. The amount of methemoglobin in the blood was determined by spectrophotometric method. The concentration of ethanol in blood and urine was measured by gas-liquid chromatography method. The correlation analysis showed that carbon monoxide affects the rate of excretion of ethanol from the body. Among individuals under 40 years of age, there was a correlation between the level of carbon monoxide and the amount of ethanol in the blood. Among older adults this correlation was not established. A direct correlation with the level of this gas in the blood and the level of ethanol in the urine among people under 40 years of age was found. Among older individuals, the opposite was observed –a high level of methemoglobin was responsible for the decreased level of ethanol. There were no correlations between methemoglobin level and age. Comparison of the studied indices did not show any sexual differences in ethanol excretion, but there were age specific features: ethanol excretion under the influence of carbon monoxide among people under 40 years old was more accelerated.Key words:hypoxia, CO intoxication, blood, methemoglobin, kidneys. Монооксид карбону являє собою токсичний газ, який не має кольору,без запаху та здатен спричиняти миттєву гіпоксію шляхом зв’язування з гем-вмісними білками. Через такі властивості він спричиняє найбільшу кількість отруєнь. Цей газ,завдяки своїм властивостям,спричиняє ураження нервової та серцево-судинної системи. Розвиток аноксії пов’язаний із впливом на систему окисного фосфорилювання у мітохондріях та розвиткомоксидативного стресу. В організмі продукується невелика кількість ендогенного монооксиду карбону внаслідок розпаду еритроцитів. Пікомолярні концентрації монооксиду карбону навіть володіють протизапальними, антиапоптичними, цитопротекторними та антипроліферативними властивостями. Нирки є одним із перших органів, який реагує на розвитокгіпоксії, вони відповідають за видалення продуктів метаболізму й токсикантів, зокрема етанолу.Зміни у функціонуванні нирок відображаються на загальному стані організму.Для дослідження отримували зразки крові та сечі від осіб із гострою інтоксикацією. У крові спектрофотометричним методом визначали вміст метгемоглобіну, який утворювався внаслідок вдихання монооксиду карбону та відповідного потрапляння до кровоносної системи. Методом газово-рідинної хроматографії вимірювали концентрацію етанолу у крові та сечі. Розрахунок кореляційних зв’язків показав, що монооксид карбону впливає на швидкість екскреції етанолу. У осіб до 40 років спостерігалася кореляція між показником рівня метгемоглобінута вмістом етанолу у крові. У осіб старшого віку цього зв’язку не встановлено. Виявлено прямий зв’язок із рівнем цього газу у крові та рівнем етанолу в сечі у осіб до 40 років. У осіб старшого віку спостерігалася зворотня реакція–високий рівень метгемоглобінуобумовлював зниження рівня етанолу. Кореляційні зв’язки між вмістом метгемоглобіну та віком не було виявлено. Порівняння досліджуваних показників не виявило статевих відмінностей у екскреції етанолу, проте виявлено вікові особливості: екскреція етанолу в умовах впливу монооксиду карбону в осіб до 40 років була більш пришвидшена.Таким чином, можна стверджувати, що монооксид карбону обумовлює зміни у функціональній активності нирок.Ключові слова:гіпоксія, інтоксикація СО, кров, метгемоглобін, нирки.

scholarly journals Optimal Nozzle Structure for an Abrasive Gas Jet for Rock Breakage

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Yong Liu ◽  
Juan Zhang ◽  
Tao Zhang ◽  
Huidong Zhang
Keyword(s):  
Gas Jet ◽  
Coal Bed ◽  
Coal Bed Methane ◽  
Rock Breakage ◽  
Glass Substrates ◽  
Expansion Waves ◽  
Erosion Rates ◽  
Gas Jets ◽  
The Impact ◽  
Nozzle Structure

Abrasive gas jet technologies are efficient and beneficial and are widely used to drill metal and glass substrates. When the inlet pressure is increased, gas jets could be powerful enough to break rock. They have potential uses in coal-bed methane exploration and drilling because of their one-of-a-kind nonliquid jet drilling, which avoids water invasion and borehole collapse. Improving the efficiency of rock breakage using abrasive gas jets is an essential precondition for future coal-bed methane exploration. The nozzle structure is vital to the flow field and erosion rate. Furthermore, optimizing the nozzle structure for improving the efficiency of rock breakage is essential. By combining aerodynamics and by fixing the condition of the nozzle in the drill bit, we design four types of preliminary nozzles. The erosion rates of the four nozzles are calculated by numerical simulation, enabling us to conclude that a nozzle at Mach 3 can induce maximum erosion when the pressure is 25 MPa. Higher pressures cannot improve erosion rates because the shield effect decreases the impact energy. Smaller pressures cannot accelerate erosion rates because of short expansion waves and low velocities of the gas jets. An optimal nozzle structure is promoted with extended expansion waves and less obvious shield effects. To further optimize the nozzle structure, erosion rates at various conditions are calculated using the single-variable method. The optimal nozzle structure is achieved by comparing the erosion rates of different nozzle structures. The experimental results on rock erosion are in good agreement with the numerical simulations. The optimal nozzle thus creates maximum erosion volume and depth.

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