Simulation research on the influence of eroded primary key strata on dynamic strata pressure of shallow coal seams in gully terrain

In Huojitu Coal Mine of Shendong mining area, the dynamic strata pressure (DSP) accidents occurred when the working faces passed the gully terrain. Focusing on this problem, we used physical simulation experimental method to thoroughly study the influence of eroded overlying primary key strata (PKS) in the gully terrain on DSP of shallow coal seams in this paper. The result show that when mining activities took place in the uphill section of shallow coal seams in gully terrain and the PKS were eroded, the blocks could not form stable bond-beam structures since the horizontal force of PKS blocks in adjacent sloping surfaces were relatively small. The sliding instability of blocks caused rapid increase of the load on the sub-key strata (SKS) blocks, which resulted into coal slide and roof fall as well as sharp drop of active columns. This led to DSP phenomenon. When the PKS blocks were intact, there was no DSP phenomenon to enable blocks provide certain horizontal force to maintain stable bond-beam structure. The simulation results were verified by the mining practices of working face 21306 crossing the gully terrain in the Huojitu Coal Mine.

Restoration of Eroded Thickness of the Neogene Strata in the Western Qaidam Basin and Its Significance for Oil and Gas Occurrence

During the Pleistocene, the western Qaidam Basin has largely experienced strong structural reconstruction and strong erosion. First, the eroded thickness of Neogene strata was restored approximately by the stratigraphic profile comparison method and plane trend surface restoring method; then, accurate calculation of erosion was recovered using vitrinite reflectance, and the erosion that was restored by the trend surface restoring method was corrected; finally, a distribution map of cumulative erosion was produced. This study marks an important achievement in that one of the most important parameters of basin tectonic evolution, sedimentary evolution, and oil and gas accumulation history has been obtained, and that a basic geological problem has been solved in the Qaidam Basin. The areas with high erosion and low erosion are shown in the map and a close relation between the distribution of oil and gas fields and erosion was recognized. Large and medium oil and gas fields are mainly distributed in areas with medium and low erosion. It is difficult to form large-scale oil and gas accumulation in areas in which erosion is more than 2000 m. The mechanism of the relation between oil and gas distribution and erosion is explained. This study will be of use in predicting the distribution of oil and gas.

Effect of erosion on corrosion of API X120 steel in relation to erodent particle size

The nature of the solid erodent particles present in corrosive petroleum fluid can cause transporting pipeline to experience severe erosion and corrosion damages. The effect of erosion on corrosion behavior of API X120 steel was investigated using aluminum oxide and silicon carbide particles with different sizes as erodent and 3.5wt.% NaCl aqueous solution saturated with carbon dioxide as a corrosive medium. The effect of the erodent particle size on the corrosion behavior of the steel material at different particle speeds and impact angles was investigated using weight loss, potentiodynamic polarization and surface analysis techniques. The erosion results confirmed that the material damage increased with increasing particle speed. It was observed that in carbon dioxide-saturated saline solution, deposition of protective iron carbonate film occurred on the steel surface. It was found that the corrosion film can provide better protection at lower particle speed than at higher speed. The ratio of total erosion-corrosion (S)/effect of erosion on corrosion (T) analysis confirmed that at higher S/T ratio, the particle speed and material removal rate are low and vice versa at lower S/T ratio. Lower S/T values for the combined erosion and corrosion tests performed with erodent silicon carbide particle compared to erodent aluminum oxide particle showed that erosion enhancement of corrosion is more evident in the test performed using aluminum oxide particle than using silicon carbide particle. The result also suggests that when subjected to larger size erodent particle, the damage to pipeline due to effect of erosion on corrosion process can be more significant compared to smaller size erodent particle.

Restoration of eroded stratal thickness in key periods of tectonic change in a multi-stage superimposed Tarim Basin in China

With an area of 56×104km2, the Tarim Basin is the largest inland basin in China and is also generally acknowledged as one of the most important areas for potential oil and gas exploration. On the basis of data from 22 regional seismic profiles and 40 drilling wells, 15 important first-order and second-order regional unconformities were defined.Almost all the main unconformities are superimposed unconfomities. Since the Cambrian, 5 key periods of tectonic change have occurred during the evolution of the Tarim Basin. The total eroded stratal thickness of the above-mentioned unconformities was calculated by using the method of virtual extrapolation of seismic reflection. The results indicate that the total eroded stratal thickness of different periods is quite different in different locations of the basin. Taking the Upper-Middle Ordovician as an example, its thickness restoration of eroded strata was calculated into individual stages i.e. its thickness restoration of eroded strata was calculated to different tectonic periods. Otherwise, as for the specific period of tectonic change, the underlying strata were, respectively eroded and thus the thickness restoration of eroded strata was calculated into individual intervals. Taking the Early Hercynian period as an example, the eroded stratal thickness was calculated into individual intervals to calculate the ratio of intervals of various ages occupying the total eroded thickness. The results show that for the same stratum, its degree of erosion is quite different in different periods and at different locations, due to the varying influence of tectonic movement. The unconformities of some key periods of tectonic change have different controls on the degree of erosion and the eroded range of the individual period of the underlying strata which are the typical characteristics of multi-stage superimposition of unconformities in the Tarim Basin.

Social perception of soil conservation benefits in Kondoa eroded area of Tanzania

A soil conservation project was implemented in Tanzania for over 30 years.This study applied a socio-economic approach to examine and analyse the benefits of soil conservation in the Kondoa eroded area of Tanzania by conducting a household survey of 240 households.The study findings show that 89%and 70%of respondents consider soil conservation activities have increased vegetation and soil fertility,respectively.Decreased soil erosion was perceived by 68%of respondents,increased firewood by 98%,increased fodder by 50%,high crop yields by 56%,and food sufficiency by 68%.These are the outcomes of conservation tillage,integrated farming and use of organic fertilizers,controlled stall feeding,agroforestry,construction of cut off drains,contour bunds and contour ridges cultivation,which are the main land use practices in the area.Access to extension services,household sizes,long term land ownership,crop incomes and awareness of soil conservation project were found to determine the level of participation in soil conservation.Major challenges are the lack of sustainability of those activities because of a recent policy decision to withdraw conservation investment.Despite the challenge,this study concluded that past government efforts on soil conservation activities initiated since the early 1970s through decentralization,institutional collaboration,socioeconomic support to farmers and continuous local community participation in restoring the degraded ecosystem of Kondoa have contributed to ensure environmental and socio-economic sustainability in the area.

Assessment of soil erosion in the Irga watershed on the eastern edge of the Chota Nagpur Plateau,India

Human activities to improve the quality of life have accelerated the natural rate of soil erosion.In turn,these natural disasters have taken a great impact on humans.Human activities,particularly the conversion of vegetated land into agricultural land and built-up area,stand out as primary contributors to soil erosion.The present study investigated the risk of soil erosion in the Irga watershed located on the eastern fringe of the Chota Nagpur Plateau in Jharkhand,India,which is dominated by sandy loam and sandy clay loam soil with low soil organic carbon(SOC)content.The study used the Revised Universal Soil Loss Equation(RUSLE)and Geographical Information System(GIS)technique to determine the rate of soil erosion.The five parameters(rainfall-runoff erosivity(R)factor,soil erodibility(K)factor,slope length and steepness(LS)factor,cover-management(C)factor,and support practice(P)factor)of the RUSLE were applied to present a more accurate distribution characteristic of soil erosion in the Irga watershed.The result shows that the R factor is positively correlated with rainfall and follows the same distribution pattern as the rainfall.The K factor values in the northern part of the study area are relatively low,while they are relatively high in the southern part.The mean value of the LS factor is 2.74,which is low due to the flat terrain of the Irga watershed.There is a negative linear correlation between Normalized Difference Vegetation Index(NDVI)and the C factor,and the high values of the C factor are observed in places with low NDVI.The mean value of the P factor is 0.210,with a range from 0.000 to 1.000.After calculating all parameters,we obtained the average soil erosion rate of 1.43 t/(hm^(2)•a),with the highest rate reaching as high as 32.71 t/(hm^(2)•a).Therefore,the study area faces a low risk of soil erosion.However,preventative measures are essential to avoid future damage to productive and constructive activities caused by soil erosion.This study also identifies the spatial distribution of soil erosion rate,which will help policy-makers to implement targeted soil erosion control measures.

Evaluation of soil loss severity and ecological restoration approach for sustainable agriculture in the Hindu Kush, Karakoram and Himalaya region

Soil erosion has resulted in removal of the topsoils containing fine soil particles and plant nutrients, causing decrease in soil fertility in the Hindu Kush, Karakoram and Himalaya(HKH) region. The existing production of cereal crop grains has been reduced to one third of the potential crop grains production owing to land degradation and poor farming practices. It is necessary to assess risk of soil loss and identify appropriate controlling measures to address issues of low agriculture productivity and water insecurity in the region. In the present study, severity of soil loss was predicted using Revised Universal Loss Equation(RUSLE) and ecological measures were identified for sustainable mountain agriculture in the HKH region of Upper Indus Basin, Pakistan. Overall 62.6% area was found to have very low risk of soil loss, i.e., <5 t/(ha·yr), 15.8% area low risk, i.e., 5-25 t/(ha·yr) and 7.5% area moderate risk, i.e., 25-50 t/(ha·yr) in the region. The risk was high, i.e., 50-100 t/(ha·yr) and very high, i.e., >100 t/(ha·yr) in about 6.8% and 7.4% areas respectively. The mean rate of soil loss was about 41.9 t/(ha·yr) in the Hindu Kush, 31.1 t/(ha·yr) in the Himalayas, 18.8 t/(ha·yr) in the Karakoram and overall 29.7 t/(ha·yr) in the three HKH ranges. As such no considerable measures have been adopted by the communities for restoration of the degraded areas except raising fruit/farm trees and supporting limited social forestry for their livelihoods. The slopes cleared for cultivation and susceptible to erosion may be stabilized through sowing/planting of multi-purpose plant species and formation of proper bench terraces. The conservation of forest ecosystem and pastures at higher elevations would help in reducing overland water flow, risk of flash flood hazard and minimizing sediment loads in the downstream. It is essential to adopt site-specific resource conservation techniques and restore possible ecosystem health for sustainable agriculture and economic development in the region in future.

Influence of Heavy Fuel Oil on the Thermo-Physical and Erodibility Properties of Earthen Materials

This study focuses on the use of heavy fuel oil in construction material in Burkina Faso. Its mixture with silty or clayey soil is used as a coating to reinforce the walls of raw earth constructions which are very sensitive to water. The interest of this study is to determine erodibility, water content, while highlighting the influence of the porosity accessible by water on thermal diffusion in construction material containing heavy fuel oil. The heavy fuel oil was mixed with a silty-clayey soil, in different proportions, and water to make bricks samples on which tests were carried out. At the end of the experimental tests, it appears that the water content increases gradually, but not significantly with the addition of heavy fuel oil, which causes a slight increase in the speed of heat propagation through the material with reduced porosity, particularly those containing higher quantities of heavy fuel oil. Conversely, we note a good performance of heavy fuel oil in terms of water resistance properties such as porosity accessible by water and erodibility. This allows us to conclude that the mixture of heavy fuel oil and silty-clayey soil used as a coating material could greatly reduce water infiltration into the walls of housing constructions with raw earthen materials.

Hygrothermal Properties of a Composite Based on Clay Soils and Diatomite

The purpose of this paper is to make a contribution to the use of diatomite as a mineral additive in the composition of compressed earth blocks. The aim is to study the influence of diatomite on the hygrothermal behaviour of composites based on clay soils. For this reason, two clay soils with different physicochemical and mineralogical compositions were incorporated with diatomite at percentages ranging from 5% to 50% with a step of 5 to produce compressed earth blocks. After assessing the hydric and thermal characteristics of the composites, it was found that the incorporation of diatomite into the clay matrix favours the absorption of water by capillary action for all the composites. The diatomite-amended blocks subjected to the rain erosion test were less eroded than the unamended blocks. In addition, BYD composites were found to be more resistant than BTD composites, due to the high percentage of clay in T soil. The thermal conductivity of the latter decreases respectively from 0.72 to 0.29 W/m∙K for BTD composites and from 0.52 to 0.21 W/m∙K for BYD composites. This reduction proves the thermal insulating properties of diatomite. Despite the high capillary absorption capacity of these composites, they have good thermal properties, enabling them to be used in the construction of buildings for improved indoor thermal comfort.

9种硝基苯对鱼肝微粒体EROD活性的影响

混合功能氧化酶系 (mixedfunctionoxidase,MFO)中的敏感指标 ,7-乙氧基 -异吩唑酮 -脱乙基酶 ( 7-ethoxyresorufin -O -deethylase ,EROD)已作为生物标志物 ,应用于生态毒理学研究领域。笔者以苯并 (a)芘作为阳性对照 ,采用鲤鱼肝脏体外直接染毒测定EROD的方法 ,分析了

鱼体内EROD活性对多氯联苯类的指示作用

运用鱼体肝脏中的EROD(7 ethoxyresorufin O deethylase)活性作为生态标记物 ,来指示大连近海部分水域的多氯联苯 (PCBs)类物质的污染状况。结果表明鱼体肝脏内的EROD活性可被PCBs诱导 ,导致活性异常增高 ,并与环境中特定污染物浓度之间存在着定量响应关系 ,EROD的这个特性可以用来评估海洋生态环境健康并作为预警指标。我们选取大连近海水域部分具有代表性的站位 ,分析测定其鱼样中EROD活性 ,并结合环境化学指标进行综合分析 ,证明将EROD作为指示多氯联苯类污染物的生态标记物是切实可行的 ,该方法在海洋环境监测中具有实际应用价值。

壬基酚对牙鲆肝脏EROD和GST酶活性的影响

乙氧基-异酚恶唑脱乙基酶(EROD)和谷胱甘肽转移酶(GST)是动物体内主要的解毒酶,在外源毒物的转化和代谢过程中具有重要作用。本文应用牙鲆肝脏组织中的EROD和GST酶活性作为生物标志物,研究了不同浓度的壬基酚(0,0.10,0.33和1.00 mg·L^(-1))活体暴露下2种酶的活性响应特征。结果表明,与对照组相比,暴露于低浓度(0.10和0.33 mg·L^(-1))的壬基酚中,EROD和GST酶活性均被诱导,暴露4 d后0.33 mg·L^(-1)的壬基酚处理组中EROD和GST活性的诱导率分别为99.2%和127.5%。暴露于高浓度(1.00 mg·L^(-1))的王基酚中。2种酶的活性均被抑制,4 d后EROD和GST酶活性的抑制率分别为62.0%和37.3%。该试验表明,EROD和GST酶活性的响应可用来评价环境中壬基酚的污染效应。

多氯联苯CB-28对牙鲆肝脏中EROD活性的诱导作用研究

将牙鲆作为受试生物,暴露于不同浓度梯度的多氯联苯CB-28中72h后,发现受试生物肝脏内的EROD活性随着加标量的增加显著上升,并与污染物浓度之间存在着显著的正相关关系,因此牙鲆肝脏内的EROD活性与环境中特定污染物浓度之间存在着定量响应关系,EROD的这个特性可以作为评估海洋生态环境健康的预警指标.同时也讨论了EROD活性测定的最佳实验条件,并剖析了EROD活性作为监测指标应用的局限性.

多氯联苯(PCBs)胁迫下鲫鱼肝脏EROD酶活性与血清性激素含量的相关性研究

以鲫鱼(Carassius auratus)为试验鱼类,研究其暴露于不同浓度的PCBs(多氯联苯)后鱼肝组织中EROD酶活性和血清性激素含量的动态变化,探讨了2者间的相关性。结果表明,鲫鱼在PCBs中暴露后,其肝脏组织中EROD酶被诱导,酶活性随PCBs浓度增大而增强,呈明显的剂量-效应关系;EROD酶活性随暴露时间延长而上升,10 d后达平衡;鲫鱼血清中睾酮含量随PCBs浓度增大和暴露时间延长呈下降趋势,但雌二醇含量则显著上升,表明PCBs对鱼类具有环境雌激素效应;在一定浓度范围内,EROD酶活性与血清睾酮含量呈负相关,与血清雌二醇含量呈正相关。因此可用鱼肝EROD酶和血清性激素含量的协同变化作为污染生物标志物来评价PCBs的早期污染生态效应。

硝基芳烃对鲤鱼肝EROD活性影响的体外研究

在体外实验条件下 ,研究了 9种硝基芳烃化合物对鲤鱼肝脏 7 乙氧基异吩唑酮 脱乙基酶 (EROD)的影响 .结果表明 ,9种硝基芳烃化合物对EROD均有激活作用 ,在实验浓度范围内 ,EROD活性与浓度之间存在剂量 效应关系 .实验发现苯环上同一位置的取代基不同或同一取代基在苯环上的位置不同 。

被动式采样器与原位鱼体暴露用于监测水体Ah受体效应的比较研究

采用被动式采样器SPMD结合H4ⅡE鼠肝癌细胞离体EROD测试的方法来评价水体中Ah受体效应物质的污染水平．以多环芳烃（PAHs）为目标化合物，在太湖梅梁湾地区选取了5个站点，同时放置SPMD采样器和笼养鲫鱼进行32d的现场原位暴露实验，然后对SPMD样品提取液进行化学分析和离体EROD测试，对鱼肌肉样进行化学分析和对肝胰脏样进行活体EROD测试．结果表明，随着暴露时间的延长，SPMD样品提取液诱导EROD酶的能力逐渐增强，经过32d暴露的SPMD样品的提取液其诱导的EROD酶活相当于TCDD的毒性当量值为3．8～6．2Pg／g，而且根据化学分析结果计算的PAHs相当于TCDD的毒性当量值与离体生物测试结果之间相关性很好（R0=0．88），说明PAHs是引起该地区水体EROD效应的一个重要诱导因子；根据化学分析结果而配制的模拟样品的离体EROD测试结果表明，多环芳烃类物质对梅梁湾地区水体Ah受体效应的贡献约为40％～50％．研究还发现，SPMD提取液离体EROD测试结果与同时暴露的鱼体肝胰脏的活体EROD测定结果之间也存在较好的相关性（R^2=0．62）。因此认为，SPMD结合离体EROD测试的方法能够很好的用于评价水体中Ah受体效应物质的污染水平，并能够用于揭示特定化合物与相应的生物效应之间的定量关系。

利用化学分析和生物测试方法比较研究污染土壤中芳烃受体效应物质的积累

长期使用污水或再生水灌溉的潜在生态风险已经引起普遍关注,但是少有研究持久性有机有毒物质在土壤中积累所产生的慢性毒性.采用7-乙氧基-异吩唑酮-脱乙基酶(EROD)方法测试了北京郊区某再生水灌溉土壤中的芳烃受体效应物质,并用2,3,7,8-TCDD标定出相应的二英毒性当量(TEQbio).同时利用化学分析得到的土壤中16种多环芳烃(PAHs)的含量,根据文献报道毒性当量因子(TEF)换算成二英的毒性当量(TEQPAHs).分析生物测试的结果,发现灌溉土壤中芳烃受体效应物质的毒性当量浓度最高达97.4 ng/kg,明显高于地下水灌溉背景土壤(56.0 ng/kg).通过化学分析和计算得到的TEQPAHs所占TEQbio的比重则由背景土壤的10.3%增加到78.6%.因此,再生水灌溉导致芳烃受体效应物质在土壤中累积,其中相当一部分是由于16种优先控制PAHs在土壤中累积引起.

利用EROD生物测试法快速筛选二噁类化合物

环境样品采集于湖北省鸭儿湖地区。每一样品分作两份，一份用于高分辨色质联用多离子检测法测定，另一份样品的提取液经多层色谱净化后再用７－乙氧基－异吩 唑酮－脱乙基酶（ＥＲＯＤ）活力诱导法进行生物测试。ＰＣＤＤｓ／ＰＣＤＦ＿ｓ和ＰＣＢ＿ｓ总的ＴＣＤＤ毒性等价指数（ＴＥＱ＿ｓ）最高，分别为１０９０ｎｇ／ｋｇ和９９６ｎｇ／ｋｇ。说明湖中二 类化合物来源于附近化工厂有机氯生产排放的污水。同时，周围农田中发现的二 类化合物数量少得多。这些化合物可能是来自于污水灌溉或大气尘降。在本研究中，ＥＲＯＤ生物测试法具有良好的剂量效应关系，适合于对环境样品中的二 类化合物进行快速定量筛选，而ＨＲＧＣ／ＨＲＭＳ－ＭＩＤ对生物测试所获得的数据作了进一步确认。

测定5种高环多环芳烃毒性当量因子并应用于太湖梅梁湾表层沉积物分析

作用位点和作用机理相同的污染物通常具有毒性加合作用,但是各个污染物对总体毒性的贡献并不相同,因此需要采用等毒性当量方法进行归一化．本研究选取了5种具有较强芳烃受体效应的多环芳烃(PAHs),通过大鼠肝癌细胞株H4ⅡE体外EROD酶诱导试验,得到相应的剂量／效应关系曲线,并计算了单个PAH的毒性当量因子 (EROD-TEF)．研究结果表明,不同PAH对EROD响应的EC50有较大区别,毒性相对强弱按照苯并[k]荧蒽>茚并 [1,2,3-cd]芘>苯并[a]芘>苯并[b]荧蒽>苊的顺序递减,对应的EROD-TEF值分别为1．1×10-4、3．0×10-5、3．9×10-6、 2．8×10-6和1．5×10-6．利用所得到的EROD-TEF值和气相色谱-质谱(GC-MS)联用方法测定的太湖梅梁湾地区表层沉积物中16种PAHs的浓度,计算得到5种PAHs的2,3,7,8-TCDD毒性当量TEQPAH,并与体外EROD酶诱导生物测试方法测得的表层沉积物毒性当量EROD-TEQ进行了比较．结果显示,两者间存在较好的线性关系(r2=0．65, p<0．05),证明实验测得的EROD-TEF值能够用于实际样品的分析;所研究的沉积物样品中5种PAHs对总芳烃受体效应的贡献均大于50％,表明PAHs是太湖梅梁湾地区表层沉积物中主要的芳烃受体效应活性物质,其可能引起的环境风险应得到进一步重视．