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64. Study on the DNA damage induced by coal tar pitch fume extracts in rat alveolar macrophage and i
The carcinogenic mechanism of coal tar pitch (CTP) as a recognized carcinogen has been studying. It is widely believed that the carcinogenicity of CTP is based on the genotoxicity of CTP. In the process of carcinogenesis caused by extrinsic chemical substance, the DNA damage mainly occurred in the initiation phase. UP to now, the most sensitive detecting endpoint for DNA damage is to detect DNA single strand breaks. The single cell gel electrophoresis has been rapidly becoming a widely used analytical procedure during the last few years, which can detect DNA strand breaks. The method is a fast, relatively inexpensive, easy to perform, non-radioactive, and very sensitive method. This method suits to different tests in vitro or in vivo. Virtually any eukaryotic cell, which could be made into single cell suspensions, can be processed for analysis of DNA damage using the single cell gel electrophoresis. The aim of the study is to investigate the role of DNA damage induced by CTP fume in rat AM, to examine the changes of ROS, MDA and SOD, and to explore the mechanism of DNA damage by CTP fume. The present study is in favor of studying the mechanism of mutagenesis and carcinogenesis induced by CTP. Method: The healthy male Wistar rats were anesthetized intraperitoneally with 40 mg pentobarbital sodium per kilogram of body weight. The animals were exanguinated by excising femoral, and collected the rat alveolar macrophage by Joseph's method. The concentration of AM had been regulated to 1.5×106 cell/ml. AMs, which had been cultured in 24-well culture plate, were divided into 4 groups. These cells were exposured to 5.0 μg/ml extracts of coal tar pitch fume, and contacted with 500 μM, 1 000 μM, and 2 000 μM of GSH respectively. These cells were divided into 4 groups. After incubation 24 hours, the indexes that had been used above were measured. Results: ①The DNA strand breaks induced by coal tar pitch fume extracts: After undergoing electrophoresis, the ‘comet’ cells are seldom in control group, but the ‘comet’ cells increased significantly in experimental groups. When the concentration of CTP fume extracts increased from 0 to 10.0 μg/ml, the incidences of ‘comet’ cell increased from 6.0% to 92.0%. There were significant differences in all groups (P...
2020-06-12 16:19:30浏览：1426
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A back analysis of the temperature field in the combustion volume space during underground coal gasi
The exact shape and size of the gasification channel during underground coal gasification (UGC) are of vital importance for the safety and stability of the upper parts of the geological formation.In practice existing geological measurements are insufficient to obtain such information because the coal seam is typically deeply buried and the geological conditions are often complex.This paper introduces a cylindrical model for the gasification channel.The rock and soil masses are assumed to be homogeneous and isotropic and the effect of seepage on the temperature field was neglected.The theory of heat conduction was used to write the equation predicting the temperature field around the gasification channel.The idea of an excess temperature was introduced to solve the equations.Applying this model to UCG in the field for an influence radius,r,of 70 m gave the model parameters,u1,2.3..,of 2.4,5.5,8.7...By adjusting the radius (2,4,or 6 m) reasonable temperatures of the gasification channel were found for 4 m.The temperature distribution in the vertical direction,and the combustion volume,were also calculated.Comparison to field measurements shows that the results obtained from the proposed model are very close to practice....
2020-06-12 16:19:28浏览：1424
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On-line tracking of pulverized coal and biomass fuels through flame spectrum analysis
This paper presents a new approach to the on-line tracking of pulverized coal and biomass fuels through flame spectrum analysis. A flame detector containing four photodiodes is used to derive multiple signals covering a wide spectrum of the flame from visible, near-infrared and mid-infrared spectral bands as well as a part of far-infrared band. Different features are extracted in time and frequency domains to identify the dynamic "fingerprints" of the flame. Fuzzy logic inference techniques are employed to combine typical features together and infer the type of fuel being burnt. Four types of pulverized coal and five types of biomass are burnt on a laboratory-scale combustion test rig. Results obtained demonstrate that this approach is capable of tracking the type of fuel under steady combustion conditions....
2020-06-12 16:19:27浏览：1424
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Suitable retention and recovery technology of floor coal at ends of fully mechanized face with great
Gateways at faces of great mining heights are mostly driven along the roof of coal seams. For gateway height restrictions, a 1-3 m floor coal is retained, leaving a triangular floor coal at the face ends, causing a loss of coal. In order to improve coal recovery rates and to ensure efficiency of equipment at coal mining faces, we investigated suitable retention methods and recovery technology of floor coal at face ends. The upper floor coal can directly be recovered by a shearer with floor dinting. The lower floor coal is recovered by shearer with floor dinting after advanced floor dinting and retaining a step for protecting coal sides in a haulage gateway. Field practice shows that this method can improve the coal recovery rates at fully mechanized working faces with great mining heights....
2020-06-12 16:19:27浏览：1406
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Safety research in the gasification process of novel multi-thermal-source coal gasifier
In order to collect the gas safely produced in the gasification process of the novel multi-thermal-source coal gasifier,based on its gasification skill and the characteristics of the products, this paper analyzes the possible dangers in the gasification process, devises the gasifier eruption and explosion experiments, explores the conditions of gasifier eruption and gas explosion, studies their effects on the gasification process and establishes safe operation measures. Gasifier eruption hazard occurs easily in the gasification process of one-thermal-source coal gasifier when Msio: is far higher than that in the normal adjuvant. The gas permeability in the gasifier is not the same and the power supply is too large. However, similar conditions in the gasification of multi-thermal-source coal gasifier do not produce a gasifier eruption accident so easily. When it erupts, the gasifier should be stopped and then cooled down naturally or inert gas can be sprayed on the gasifier to cool it off, and thus gas explosion can be avoided. There is a possibility of direct gas explosion, but it can be avoided when the gas in the gas collecting space is replaced slowly by supplying a small amount of power or the inert gas fills the space in the previous gasification. The time a fire is lit is strictly controlled, the gas is drawn in by using the aspirator pump, and the gasifier pressure is kept in the state of micro-positive pressure in the middle and later gasification process. The conclusion is that the gasification process of the novel multi-thermal-source coal gasifier is safe according to normal operation rules....
2020-06-12 16:19:26浏览：1431
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Underground pressure characteristics analysis in back-gully mining of shallow coal seam under a bedr
We studied underground pressure and its mechanism during back-gully mining in a shallow coal seam under a bedrock gully slope, by means of physical simulation, numerical modeling and field monitoring.The results show that the intensity of underground pressure is related to its relative position at the coalface. The underground pressure is intensive and the support resistance reaches a maximum when the coalface is at the bottom of the gully, whereas the underground pressure is moderate and decreases gradually when the coalface passes the gully. The mechanism of these changes is analyzed when the slope rotated in a reversed direction to the slope dip during back-gully mining and form an unstable, multilateral block hinged structure, due to slipping. The subsidence of multilateral blocks is considerable when the block fragmentation is small, resulting in enormous changes in the underground pressure. With an increase in the mass of the block body, the block displacement will be reduced in conjunction with an increased clamp effect by both the unbroken rocks and broken rocks in the goaf, resulting in a decrease of the underground pressure....
2020-06-12 16:19:24浏览：1419
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Coating mechanism of nano-TiO2 films on the surface of ultra-fine calcined coal kaolin particles
A new type of mineral composite was made by calcined coal kaolin.The interaction mechanism of an inorganic modification reagent TiOSO4 with the surface of ultra-fine calcined coal kaolin particles (substrate) was studied by X-ray photoelectron spectroscopy.The results show that chemisorption exists in the phase boundary between the modification agent and the substrate surface,while physical adsorption occurs on the modification layers of hydrate titanium dioxide.The interaction force was calculated and analyzed according to DLVO theory between ultra-fine calcined coal kaolin particles and hydrate titanium dioxide nano-particles in the modification system.It is shown that the both electrostatic force and van der Waals force are attractive,and the coacervation between ultra-fine calcined coal kaolin particles and hydrate titanium dioxide nano-particles leads to the coating of hydrate titanium dioxide on the surface of ultra-fine calcined coal kaolin particles....
2020-06-12 16:19:22浏览：1408
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Suitable layout of gate roads related to slice mining in an ultra-thick unstable coal seam
We determined a suitable gate road layout in slice mining in an ultra-thick unstable coal seam,using theoretical analysis and numerical calculations.Based on plasticity theory in terms of limiting equilibrium,the width of chain pillar in the upper slice was calculated to be 18 m.The stress distribution in the chain pillar after the upper slice was mined out was described with numerical simulation.The extent of the effect of stress on the upper chain pillar on the lower solid coal was obtained on the basis of an elastic solution of a distributed force loaded on a half-plane.Three layout designs for lower gate roads were proposed and a stability factor was introduced to analyze the stability of the lower pillar with numerical calculation.Gate road translation was determined as the most suitable layout method,which maximizes the extraction rate on the basis of the pillar stability....
2020-06-12 16:19:22浏览：1445
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Determination of trace multi-elements in coal fly ash by inductively coupled plasma mass spectrometr
The contents of Cr,Cu, Ni, As, Cd and Pb in coal fly ash were determined by a high resolution inductively coupled plasma mass spectrometry method.The sample digestions were performed in closed microwave vessels with HN03, HClO4 and HF.The optimum conditions for the determination were obtained.The applicability of the proposed method was validated by the analysis of coal fly ash reference material (NIST SRM 1633a). The results show that most of the spectral interferences can be avoided by measuring in the high resolution mode(maximum mass resolution R=9 000).The detection limit is from 0.05 to 0.21μg/g,and the precision is fine with relative standard deviation less than 4.3%....
2020-06-12 16:19:19浏览：1427
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Inhibition and recovery of nitrification in treating real coal gasification wastewater with moving b
Moving bed biofilm reactor (MBBR) was used to treat real coal gasification wastewater. Nitrification of the MBBR was inhibited almost completely during start-up period. Sudden increase of influent total NH3 concentration was the main factor inducing nitrification inhibition. Increasing DO concentration in the bulk liquid (from 2 to 3 mg/L) had little effect on nitrification recovery. Nitrification of the MBBR recovered partially by the addition of nitrifying sludge into the reactor and almost ceased within 5 days. Nitrification ratio of the MBBR achieved 65% within 12 days by increasing dilute ratio of the influent wastewater with tap water. The ratio of nitrification decreased to 25% when influent COD concentration increased from 650 to 1000 mg/L after nitrification recovery and recovered 70% for another 4 days....
2020-06-12 16:19:18浏览：1426
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Solid superacid-catalyzed hydroconversion of an extraction residue from Lingwu bituminous coal
A solid superacid was prepared as a catalyst.The catalyst was characterized by ammonia temperatureprogrammed desorption,surface property measurement,and analyses with scanning electron microscopy and Fourier transform infrared spectrometry.A extraction residue from Lingwu subbituminous coal was subject to non-catalytic and catalytic hydroconversion using cyclohexane as the solvent under pressurized hydrogen at 300 ℃ for 3h.The results show that the total yield of petroleum ether-extractable arenes from catalytic hydroconversion is much higher than that from non-catalytic hydroconversion.The cleavage of Car-Calk bonds in the residue could significantly proceed during catalytic hydroconversion....
2020-06-12 16:19:17浏览：1431
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Significance of Coal Seam in Recognition of Sequence Boundaries and Systems Tract of the Jurassic in
The Jurassic in the East Fukang Slope can be divided into six sequences based on sequence stratigraphy by combining logging, core and seismic data. The indicators of sequence boundaries include unconformity, coal seams,change of spore and pollen abundance, scour surfaces and base conglomerate, change of logging curve and sedimentary facies. How to determine the location of the first flooding surfaces and the maximum flooding surface is the key step to divide the systems tract. There occurred a topographic slope break in the East Fukang Slope when the Jurassic was deposited, and therefore we can recognize the location of the first flooding surface and establish the sequence stratigraphic framework with the slope break in the study area. Coal seams regionally distributed are correlatable and isochronic, and record the termination of a depositional event or episode. So, the regional coal seam (more than 60percent coverage) can be used as the genetic stratigraphic sequence boundary, while locally distributed coal seam (less than 60 percent coverage) can be used as the systems tract boundary. The thick coal seams distributed regionally in the middle of the Badaowan Formation and the lower part of the Xishanyao Formation in the study area act as the sequence boundaries, while the thin and locally distributed coal seam acts as the systems tract boundary, which results in the correlation of the division of sequence stratigraphy of the Jurassic to the whole basin where coal seams are developed extensively....
2020-06-12 16:19:15浏览：1400
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Life Cycle Assessment of Ultra-clean Micronized Coal Oil Water Slurry
Life cycle assessment is applied to assess the ultra-clean micronized coal oil water slurry (UCMCOWS) with Si-maPro and the environmental impact of UCMCOWS on its whole life cycle is also analyzed. The result shows that the consumption of energy and products are increasing along with the deepening of UCMCOWS processing, UCMCOWS making and combustion arc the two periods which have a bigger impact on eco-system and hu-man health. As a new substitute of fuel, UCMCOWS merits to be utilized more efficiently and reasonably....
2020-06-12 16:19:12浏览：1397
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Applicable conditions for a classification system of aquifer-protective mining in hallow coal seams
Based on the conclusions of domestic and foreign research,we have analyzed the collapse-fall characteristics of overlying strata and the mechanism of aquifer-protective mining in shallow coal seam working faces at the Shendong Mine.We have selected the height of the water-conducting fracture zone in overlying strata as a composite index and established the applicable conditions of aquifer-protective mining in shallow coal seams with a multi-factor synthetic-index classification method.From our calculations and analyses of variance,we used factors such as the overlying strata strength,mining disturbing factors and rock integrity as related factors of the composite index.We have classified the applicable conditions of aquifer-protective mining in shallow coal seams into seven types by comparing the result of the height of water-conducting fractured zones of long-wall and short-wall working faces with the thickness of the bedrock.the thickness of the weathered zone and the size of safety coal-rock pillars.As a result,we propose the preliminary classification system of aquifer-protective mining in shallow coal seams.It can provide a theoretical guidance for safe applications of aquifer-protective mining technology in shallow coal seams under similar conditions....
2020-06-12 16:19:11浏览：1400
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Effects of different acclimations on high solution bacteria in coal-gas wastewater degradation
To make microbial community be applied more easily in practical biotreatment engineering,three acclimation processes were carried out in lab scale.Three kinds of mixed microorganism cultures with degradability for a gas-making plant wastewater were obtained.The degradation experiments results of coal-gas wastewater indicated that different acclimation processes had obviously impacted on degradability of microbial community,and under high sludge loading rate,mixed microorganism culture Ⅰ(obtained by H.S.B as bacteria source and raw wastewater as alone carbon and energy source)presented stronger degradability for coal gasification wastewater than the others.COD removal rate of mixed culture Ⅰ can reach 57.6% under very low MLSS when the influent COD is 900mg/L.Meanwhile,the results of microscopic examination showed that Protozoa,mainly epistylis and Vorticella species,were stronger activity and larger quantities in mixed culture Ⅰ....
2020-06-12 16:19:08浏览：1434
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