松软煤层壁式密封瓦斯抽采技术研究

高瓦斯低透气性松软顺层瓦斯抽采过程中,由于钻孔极易发生缩径、塌孔等工程问题,钻孔周围漏风严重,钻孔服务时间短,瓦斯抽采难度大且周期较长等成为瓦斯抽采的主要技术难题。通过分析松软煤层瓦斯抽采存在的关键问题,应用多孔介质渗流力学、流体平衡等理论及钻孔护孔原理,提出了松软煤层的固液耦合壁式密封技术。现场研究表明,应用固液耦合壁式密封技术抽采松软煤层瓦斯有效地阻止了巷道风流的漏入,极大地提高了瓦斯抽采效率,使得单孔瓦斯抽采浓度达90%以上,与煤矿所使用的聚氨酯袋配合密封液封孔技术相比,单孔纯瓦斯流量提高2~3倍,且抽采过程浓度稳定,对松软煤层瓦斯的高效抽采及实现煤与瓦斯共采和煤层气绿色开发理念具有重要意义。     

顺煤层水力割缝抽采煤层瓦斯渗流规律数值模拟

为得到顺煤层水力割缝抽采瓦斯渗流规律以及预测水力割缝后瓦斯气体抽采量,结合渗流力学和弹塑性力学理论,建立了水力割缝抽采煤层瓦斯的固流耦合数学模型,同时给出了相应初始条件及边界条件。利用Madab计算得到顺煤层水力割缝后煤体应力场、瓦斯压力场以及瓦斯抽采量变化规律。数值模拟结果显示：水力割缝后,煤体有效体积应力得到释放;沿割缝方向储层卸压效果明显;煤层内裂隙、裂缝数量增加,长度和张开度增大;煤体渗透性能增强;煤层气抽采量较普通钻孔有较大幅度的提高。模拟结果显示了顺煤层水力割缝抽采煤层气的优势。此模拟方法对煤层气增产工业中确定水力割缝工艺参数以及预测瓦斯产量具有重要的指导意义。     

顺层交叉钻孔预抽瓦斯技术在高瓦斯低透煤层的试验研究

针对高瓦斯低透煤层瓦斯预抽效果不佳、抽采工艺参数设置不够合理的问题,通过对交叉钻孔围岩塑性区应力叠加效应的理论分析,阐述了其增透利抽、提高本煤层瓦斯预抽效果的机理,罗列了交叉钻孔施工参数要求;结合某矿12103工作面交叉钻孔预抽瓦斯技术的试验应用,量化对比分析了两种钻孔瓦斯预抽效果。结果表明:在不增加工程量的条件下,与传统的平行钻孔相比,交叉布孔方式可将本煤层瓦斯预抽率提高0.77倍左右,有效改善了高瓦斯低透煤层瓦斯预抽效果,降低了工作面回采时瓦斯事故发生的概率,为矿井安全生产增添了保障。     

构造松软煤层钻孔多应力耦合分区失稳机理研究

构造松软煤层瓦斯抽采过程中,钻孔易发生形变、缩径及坍塌等失稳现象,从而造成钻孔及密封失效、抽采阻力增大和抽采瓦斯浓度偏低等问题。针对上述难题,基于原岩应力作用下松软煤层的力学性质及瓦斯赋存条件,分析瓦斯应力对钻孔失稳的动力效应,并通过理论及数值方法对巷道一次采动及钻孔二次采动过程中各采动因素对钻孔周围煤体弹塑性区应力峰值及范围的影响进行研究分析。结果显示:初始应力及采动半径的增大或内聚力及内摩擦角的降低均会不同程度造成应力峰值或弹塑性区域的增大,从而增加钻孔失稳的概率及范围。进而根据钻孔方向上不同应力耦合作用及采动弹塑性区域提出了钻孔分区失稳机理,对构造松软煤层钻孔密封及护孔具有重要指导意义。     

瓦斯抽采钻孔横“T”连接结构的研究与应用

瓦斯抽采管路积水问题一直是影响矿井瓦斯抽采效果的重要因素。为解决这一问题,自主设计了瓦斯抽采钻孔横"T"连接结构,该结构将从抽采钻孔内排出的水消除在抽采管路的源头,避免水进入到抽采管路中。通过在陶二煤矿的现场应用,发现该结构可有效解决瓦斯管路积水问题,并显著提高瓦斯抽采效果,使抽采总管路瓦斯抽采浓度由15%提高到25%以上,提高了近1倍;平均单孔瓦斯抽采浓度达到55%以上,矿井年瓦斯抽采量达到近700万m~3,瓦斯抽采率达到40%以上,为消除瓦斯事故,实现矿井的安全生产提供了保证。     

基于Fluent采空区瓦斯抽采仿真模拟在寺河矿的应用研究

为了提高晋煤寺河矿采空区瓦斯抽采效率低的现状,结合寺河矿采空区瓦斯抽采模式,通过分析寺河矿煤层特性,采空区抽采方法,建立瓦斯抽采模型,应用仿真模拟软件对不同瓦斯抽采方案的瓦斯运移规律进行仿真模拟,对模拟结果进行对比分析最后制定和改善了具体的采空区瓦斯抽采实施方案。     

被保护煤层底板穿层抽采钻孔合理布置方式研究

为了保障穿层抽采钻孔施工安全和提高被保护层卸压瓦斯抽采效果,通过上保护层开采邻近煤层瓦斯涌出情况的分析和上保护层开采底板煤岩体卸压特征的数值模拟分析,对不同层间距被保护层穿层抽采钻孔的合理布孔方式进行了研究。现场试验表明：下伏不同层间距被保护层底板穿层抽采钻孔不同的布置方式能保障钻孔的安全施工和被保护层卸压瓦斯高效抽粟。     

大兴矿N2-203开采保护层卸压瓦斯抽采研究

针对开采保护层时瓦斯容易超限的问题,分析了开采煤层过程中,保护层在采动应力作用下卸压增流效应及卸压瓦斯运移规律,采用了对被保护层瓦斯卸压抽采和分源治理的技术措施,以大兴矿瓦斯治理为例,通过实施"封堵漏风口、浅埋大管路、短抽上隅角"等开采保护层和钻孔抽采瓦斯等关键性治理技术,解决了开采高瓦斯煤层群过程中综采面大面积悬顶上隅角空间和回风流中浓度超限的问题,实现瓦斯资源的回收再利用。     

高位抽采下近距离煤层采空区复合致灾数值模拟研究

从煤矿井下安全生产的角度出发,以西铭矿近距离煤层采空区的特点为例,建立了一种高位巷抽采下近距离煤层采空区三维模型。通过Ansys Fluent对采空区气体流动控制方程和非均匀瓦斯释放源项、浮煤耗氧源项进行三维稳态解算发现,随着高位巷抽采流量的不断增大,抽采瓦斯总量逐渐升高,抽采浓度和抽采效率逐渐降低,在抽采流量升至30 m3/min后,所有变化趋势变缓。上部邻近煤层高氧浓度富集区不断增大,下部遗煤处无明显变化。研究表明,采用抽采流量都为20 m3/min的高位巷与上隅角埋管相结合的瓦斯抽采方法能有效控制采空区复合致灾隐患。     

瓦斯抽采钻孔“两堵一注”带压封孔技术及装置研究

针对瓦斯抽采过程中存在瓦斯抽采浓度低、抽采量小等问题,提出了"两堵一注"带压封孔技术,并根据封孔过程中存在的问题,自主研制了气动增压封孔装置。阐述了"两堵一注"带压封孔技术及装置的工作原理及工艺流程,并进行了现场工业试验,结果表明:"两堵一注"带压封孔技术及装置的应用实现了封孔工艺由手动封孔向机械化封孔转变,能够实现在指定深度封孔,提高了封孔质量,使单孔瓦斯抽采负压由8 k Pa提高到18 k Pa以上;单孔瓦斯抽采浓度由35%提高到65%以上;单孔瓦斯抽采量由0.04~0.05 m3/min左右提高到0.11 m3/min左右,为快速实现瓦斯抽采达标和矿井安全高效生产提供了保证。     

Permeability tracers and serum proteins

Zusammenfassung Es wird gezeigt, dass die Permeabilität der Gefässwand durch an Serumeiweissfraktionen gebundene Markierungssubstanzen geprüft werden kann.     

Permeability barrier or ion pump?

Zusammenfassung An einem einfachen Modell wird die durch Temperatur beeinflusste Aktivität des Natrium-Transportes in biologischen Membranen erklärt. Daraus kann der Schluss gezogen werden, dass der Natrium-Transport in der isolierten Krötenblase normalerweise durch die Ausdehnungsmöglichkeit der mukosalen Zone begrenzt ist und dass Aldosteron in der Lage ist, diese Ausdehnung zu fördern.     

Permeability of rat heart myocytes to cytochrome c

Rat heart myocytes undergoing progressive damage demonstrate morphological changes of shortening and swelling followed by the formation of intracellular vacuoles and plasma membrane blebbing. The damaged myocytes displayed impaired N,N'-tetramethyl-p-phenyldiamine (TMPD) ascorbate-stimulated respiratory activity which was restored by the addition of reduced cytochrome c to the cell culture medium. To clarify the role played by cytochrome c in the impairment of cell respiration, polarographic, spectrophotometric and fluorescence as well as electron microscopy imaging experiments were performed. TMPD/ascorbate-stimulated respiratory activity returned to control levels, at approximately 20 microM cytochrome c, establishing the threshold below which the turnover rate by cytochrome c oxidase in the cell depends on cytochrome concentration. Mildly damaged cardiac myocytes, as indicated by cell shortening, retention of visible striations and free-fluorescein exclusion, together with the absence of lactate dehydrogenase leakage and exclusion of trypan blue, were able to oxidize exogenous cytochrome c and were permeable to fluorescein-conjugated cytochrome c. The results, while consistent with an early cytochrome c release observed at the beginning of cell death, elucidate the role played by cytochrome c in the kinetic control of mitochondrial electron transfer under pathological conditions, particularly those involving the terminal part of the respiratory chain. These data are the first to demonstrate that the sarcolemma of cardiac myocytes, damaged but still viable, is permeable to cytochrome c.     

Permeability of cellophane membranes to parotid during dialysis.

Pooled paratoid saliva was dialyzed in cellophane membranes against water for periods of up to 1 week and loss of proteins was monitored by acrylamide gel-electrophoresis. A gradual loss of cationic proteins was observed whereas anionic proteins were not appreciably affected. Loss of the cationic proteins could be greatly reduced by performing dialyses against dilute electrolyte solutions rather than water. These effects were attributed primarily to electrostatic changes associated with the dialysis membranes.     

Permeability of cellophane membranes to parotid proteins during dialysis

Summary Pooled parotid saliva was dialyzed in cellophane membranes against water for periods of up to 1 week and loss of proteins was monitored by acrylamide gel-electrophoresis. A gradual loss of cationic proteins was observed whereas anionic proteins were not appreciably affected. Loss of the cationic proteins could be greatly reduced by performing dialyses against dilute electrolyte solutions rather than water. These effects were attributed primarily to electrostatic charges associated with the dialysis membranes.The assistance of Mr E. Pederson and Dr G. Clark is gratefully acknowledged. Supported by Naval Medical Research and Development Command Project MR005.19 6048, Bethesda, Maryland. The opinions expressed herein are those of the authors and are not be construed as reflecting the views of the Navy Department or the Naval Service at large. The use of commercially available products does not imply endorsement of these products or preference to other similar products on the market.Deceased.     

Permeability coefficients of the egg-case membrane ofScyliorhinus canicula L.

Summary The cleidoic egg-case of the dogfish appears to have a highly porous and permeable outer membrane, the pore radius being computed to be 13.6 Å. It does not present any physiological barrier to small molecules and therefore constitutes an open ionic and osmotic system for the embryo. Being a porous protein membrane it may be of value as a model for molecular transport mechanisms.     

Permeability coefficients of the egg-case membrane of Scyliorhinus canicula L

The cleidoic egg-case of the dogfish appears to have a highly porous and permeable outer membrane, the pore radius being computed to be 13.6 A. It does not present any physiological barrier to small molecules and therefore constitutes an open ionic and osmotic system for the embryo. Being a porous protein membrane it may be of value as a model for molecular transport mechanisms.     

Permeability of the isolated human amniotic membrane to divalent cations]

Membrane potential and resistance recordings, in vitro, show that Mg++ does not pass through the amnion from the inside of the amniotic compartment to the outside of the amniotic membrane. Mg++ may become fixed on the surface or in the midst of the amniotic membrane. However, Mg++ diffuses in the opposite direction. Ca++, Ba++, Sr++ diffuse in both directions across the amniotic membrane.     

Permeability of the golden hamster placenta to inorganic lead: Radioautographic evidence

Zusammenfassung Trächtigen Goldhamstern wurde am 7. und 8. Tag²¹⁰Pb intravenös verabericht. Von den Placentamembranen und vom Embryo wurde radioaktives Metallion stark aufgenommen und die Einglagerung autoradiographisch verfolgt.     

Permeability of Ehrlich ascites cells and spectrophotometric assay of the sub-cellular enzymes

Summary A permeabilization method which allows the assay of intracellular enzymes of the Ehrlich ascites cells is described. The developmental changes in the activity of lactic dehydrogenase and glucose-6-phosphate dehydrogenase of toluene-treated Ehrlich ascites cells were studied.Acknowledgment. M.D. is grateful to CSIR for the award of Junior fellowship.