An analytical transient coal permeability model:Sorption non-equilibrium index-based swelling switch

Long-term permeability experiments have indicated that sorption-induced swelling can switch from internal to bulk depending on the evolutive sorption status.However,this sorption swelling switch mechanism has not been considered in current analytical permeability models.This study introduces a normalized sorption non-equilibrium index(SNEI)to characterize the sorption status,quantify the dynamical variations of matrix swelling accumulation and internal swelling partition,and formulate the sorption swelling switch model.The incorporation of this index into the extended total effective stress concept leads to an analytical transient coal permeability model.Model results show that the sorption swelling switch itself results in the permeability switch under stress-constrained conditions,while the confined bulk swelling suppresses the permeability recovery to the continuous reduction under displacement-constrained conditions.Model verifications show that current experimental observations correspond to the early stages of the transient process,and they could be extended to the whole process with these models.This study demonstrates the importance of the sorption swelling switch in determining permeability evolution using simple boundary conditions.It provides new insights into experimentally revealing the sorption swelling switch in the future,and underscores the requirement of a rigorous model for complex coupled processes in large-scale coal seams.

Co-liquefaction of Coal and Used Tire in Supercritical Water

The co-liquefaction of lignite coal and used tire was performed in a 250-ml batch reactor, in supercritical water under a nitrogen atmosphere to investigate the effects of temperature (380-440℃), water/feedstock ratio (4/1-10/1 (wt./wt.)) and the % used tire content in the feedstock (0-100 wt.%) on the conversion efficiency, liquid yield and oil composition attained. The maximum conversion and oil yield were 67 and 50%, respectively, obtained at 400℃ at 1 min, with water/feedstock ratio of 10/1 and 80% used tire content. The distillation characteristics of the oil products, analyzed by simulated distillation gas chromatography, revealed that the oil composition depended significantly on the reaction temperature. The co-liquefaction of coal and used tire yielded a synergistically increased level of oil production. Moreover, the total conversion level obtained with co-liquefaction alone was almost equal to those obtained in the presence of either Fe2O3 or NiMo as catalysts, under the same conditions. Therefore, supercritical water is a good medium for the dissolution of the volatile matter from a coal and used tire matrix.

Study on land use changes of the coal mining area based on TM image

Based on the two temporal TM images of 1995 and 2001 of one coal mining area,analyzed the variety information of the coal mining area.Relative registration were done with the two images firstly,then cut out the study area for experimental data,classi- fied the coal mining area using supervised classification in ERDAS,the coal mining area will be divided into five categories as water body,agricultural land,construction land,coal mining area and other land.Make land use change matrix,the result shows that in the six years of 1995 to 2001,the change of the utilize of the land is greatly,the main represent is showed as follows: the area of water body,agricultural land and coal mining land had con- tinually increased,on the contrary,construction area and other decreased.The percen- tage speed of the construction land is the biggest,the value reach-1.08%.The main rea- sons is that with the exploitation of the coal mine and the reclaim of the land,the exploita- tion of the coal mining land make the agricultural land and construction area convert into coal mining land,on the other hand with the backfill of the subsided waterlogged land and the reclaim of the subsided land make the coal mining land convert into agricultural land.

Spatial Structure Adjustment Strategies of the Coal Resource-Based Cities during the Mature Period: A Case Study of Pingdingshan

Coal cities are the main part of the resource-based cities in China, and the benign development of coal cities' spatial structure has a direct impact on these cities' future economic and social development, as well as the urban residents' welfare. Land use fragmentation is the most typical morphological characteristic of the coal city's spatial structure development. In this paper, Pingdingshan City of Henan Province in China is taken as an example. Through empirical analysis, the urban spatial structure development processes of a typical coal resource-based city in its mature period are illustrated, and the formation reasons and potential mechanism behind coal city land use fragmentation are explored, and the measurement method of land use fragmentation degree of the coal city is put forward. On the above basis, the appropriate adjustment strategies and methods aimed at the coal city spatial structure are found out and given. This study is a good guideline and reference for the spatial structure planning and land use planning of the coal city during the mature and declining period, which is of great help to the sustainable development and industrial structure transformation of the coal city. It also has certain reference significance for the coal city in the growth period.

The Forming-Mechanism and Role of Creativity Thinking in Dry Coal Beneficiation of Coal with Air-Dense Medium Fluidized Bed

In this paper, the authors point out that the Creativity is an inevitable request in solving engineering and technological problems and that the coal beneficiation technology with air dense medium fluidized bed is a result of reversal thinking, and its forming mechanism is the use of other things for reference and the transplantation.

The Methodology of Melioration and Restoration of the Largest Dumps of the Most Coal Basin

Reclamations of dumps in the Most Basin that is located in the North Bohemia consist of restoration of extremely unfavourable properties of rocks that are poured down onto the dump body. These rocks come from the surface layer and the layer where coal bed is present. Sands, clay sands and kaolin (illitic clays) are the main components that occur in the material. Other components are predominantly organic (coal) mass, siderite and pyrite. This report briefly summarizes the history and present of ore, non-metallic and coal mining in the region and addresses in detail the issue of moderating the consequences of mining, which is one of the principal activities of the Research Institute for Brown Coal, j.s.c. in Most. The concept of landscape reclamation in the largest dumps after mining ends, the technical reclamation methodology and the well considered use of fertilizable soil are main results presented in this article.

Prospect of Clean Coal Technologies to be Used in Fujian Province Power Industry

This paper is based on the existing status and development prediction of Fujian power industry, and describes that the structure of energy sources for generating power which will mainly use coal, will not be changed in the 2010s and 2020s in Fujian Province. In order to meet the requirements of high efficiency and envirofimental protection, the usage of clean coal technologies for power generating will be an inevitable option and the technologies will occupy the important position in Fujian power industry. This paper puts forward the staged targets and measures of developing and utilizing clean coal technologies, suggests that all government depotments related should give support and guarantee in policies and conditions, and welcome technical and economic cooperation at home and abroad, which is good for co-development of both parties.

Are vulnerable farmers more easily influenced?Heterogeneous effects of Internet use on the adoption of integrated pest management

The Internet is believed to bring more technological dividends to vulnerable farmers during the green agriculture transformation.However,this is different from the theory of skill-biased technological change,which emphasizes that individuals with higher levels of human capital and more technological endowments benefit more.This study investigates the effects of Internet use on farmers'adoption of integrated pest management(IPM),theoretically and empirically,based on a dataset containing 1015 farmers in China's Shandong Province.By exploring the perspective of rational inattention,the reasons for the heterogeneity of the effects across farmers with different endowments,i.e.,education and land size,are analyzed.The potential endogeneity issues are addressed using the endogenous switching probit model.The results reveal that:(1)although Internet use significantly positively affects farmers'adoption of IPM,vulnerable farmers do not benefit more from it.Considerable selection bias leads to an overestimation of technological dividends for vulnerable farmers;(2)different sources of technology information lead to the difference in the degree of farmers'rational inattention toward Internet information,which plays a crucial role in the heterogeneous effect of Internet use;and(3)excessive dependence on strong-tie social network information sources entraps vulnerable farmers in information cocoons,hindering their ability to reap the benefits of Internet use fully.Therefore,it is essential to promote services geared towards elderly-oriented Internet agricultural technology information and encourage farmers with strong Internet utilization skills to share technology information with other farmers actively.

A model to determining the remaining useful life of rotating equipment,based on a new approach to determining state of degradation

Condition assessment is one of the most significant techniques of the equipment’s health management.Also,in PHM methodology cycle,which is a developed form of CBM,condition assessment is the most important step of this cycle.In this paper,the remaining useful life of the equipment is calculated using the combination of sensor information,determination of degradation state and forecasting the proposed health index.The combination of sensor information has been carried out using a new approach to determining the probabilities in the Dempster-Shafer combination rules and fuzzy c-means clustering method.Using the simulation and forecasting of extracted vibration-based health index by autoregressive Markov regime switching(ARMRS)method,final health state is determined and the remaining useful life(RUL)is estimated.In order to evaluate the model,sensor data provided by FEMTO-ST Institute have been used.

pH-Controlled DNA Molecular Switch Using Minidumbbell

DNA is an attractive biomaterial for constructing nanomachines and nanomaterials owing to their self-recognition and self-assembly properties.In addition to the well-known double helical structures,DNA molecules can also form a variety of unusual structures like hairpins,triplexes and quadruplexes.These unusual DNAs sometimes have advantages over double helical DNAs in constructing nanomachines such as enhanced thermodynamic stability and higher sensitivity to external stimuli,which made them as promising motifs in recenttwo decades.Regardless of how complicated DNA-based nanomachines are,the fundamental concept in these nanomachines is based on a proper design and usage of DNA molecular switch.Among the reported DNA molecular switches,pH-controlled systems show great potentials in drug delivery and cellular pH sensing.Up to now,most of the reported pH-controlled molecular switches used i-motif or triplex DNAs.However,owing to the relatively long sequence requirement for the formation of i-motif and triplex DNAs,an invading DNA strand needs to be added to activate the molecular switch,and thus DNA wastes will be generated into the system and a full structural conversion will usually take a relatively long time of minutes to hours.To overcome the disadvantages of DNA waste generation and slow kinetics,molecular switches using smaller-size,thermodynamically stable and pH-sensible unusual DNA structures will have the advantages of easier manipulation and faster kinetics.Recently,we discovered a new type of unusual DNA structure called the minidumbbell(MDB)which is formed by a single-strand 8-nucleotide sequence.The MDB is composed of two type II tetraloops in which the first and fourth loop residues form loop-closing base pairs,the second loop residues fold into the minor groove to form base-base stacking or mispairing interactions,and the third loop residues stack on their nearby loop-closing base pairs.In particular,the MDB formed by a sequence containing two CCTG repeats has a relatively low melting temperature(Tm)of^22℃at pH 7.0,whereas its Tm can be significantly increased to^46℃at pH 5.0 due to the formation of a three hydrogen bond hemiprotonated C+·C mispair in the minor groove.This MDB,when combined with its complementary sequence,shows instant and complete structural conversions when the pH switches between 5.0 and 7.0 without using an invading DNA strand,serving as a simple and efficient pH-controlled molecular switch.In order to allow the incorporation of fluorophores to the two termini of the MDB,we aim to design a thermodynamically more stable MDB structure in this study.Through a rational design by introducing hydrophobic interactions to the MDB formed by the sequence containing two CCTG repeats at pH 5.0,we obtained an MDB structure with a record-high Tm of^62℃.Furthermore,this MDB was found to exist stably in the presence of 5’and 3’-overhanging residues,revealing its capability of being attached with fluorophores or other functional groups,and thus making it potentially a versatile pH-controlled molecular switch for designing nanomachines and nanomaterials.

Broad-Band All-Optical Wavelength Conversion of Differential Phase-Shift Keyed Signal Using an SOA-Based Nonlinear Polarization Switch

Broad-band all-optical wavelength conversion of differential phase-shift keyed （DPSK） signal is experimentally demonstrated. This scheme is composed of a one-bit delay interferometer demodulation stage followed by a semiconductor optical amplifier （SOA） based nonlinear polarization switch. A wavelength converter for the 10 G b/s DPSK signal is presented, which has a wide wavelength range of more than 30 nm. The converted signals experience small power penalties less than 1.4 dB compared with the original signal, at a bit error rate of 10-9. Additionally, the optical spectra, the measured waveforms and the open eye diagrams of the converted signals show a high quality wavelength conversion performance.

Vertically Integrated Thermo-Optic Waveguide Switch Using Optical Polymers

We propose and fabricate a vertically integrated thermo-optic waveguide switch. It controls the optical path between two vertically stacked waveguides using the thermo-optic effect of optical polymer. The measured crosstalk is less than -10 dB.

超临界直流锅炉入炉煤快速切换装置研究与应用

为应对日益频繁的机组负荷全天快速调整和缓解煤炭成本压力,笔者公司通过对锅炉原煤仓进行研究,制造和安装了基于原煤仓分仓可大范围燃用非设计煤种和低水份、高热值煤种的新型入炉煤快速切换系统,该系统可以在线快速切换原煤仓分仓中的两种煤质,实现高负荷和快速升负荷条件下燃用低水份、高热值煤种,低负荷和降负荷条件下燃用大范围燃用非设计煤种,解决低负荷磨煤机投运台数少引起炉内燃烧不均问题和燃用高水分低热值煤质导致的升负荷速度慢及高负荷磨出力不足的问题。优化不同负荷条件下大范围燃用非设计煤的掺配位置、比例,得到最佳的掺配方案。

煤矸石土壤调理剂对毛乌素沙地柳枝稷生长的影响

提高毛乌素沙地保水保肥性能,旨在为黄河“几”字弯生态保护与高质量发展提供理论支持。为了探究煤矸石对毛乌素沙地的改良效果,以柳枝稷为指示作物,采用随机区组设计,设置煤矸石土壤调理制剂含量分别为0%(CK)、90%(ST1)、84%(ST2)、78%(ST3)、66%(ST4)、54%(ST5),研究不同煤矸石含量的土壤调理剂对毛乌素沙地土壤性质和柳枝稷农艺指标的影响。结果表明,添加煤矸石土壤调理制剂可有效改善风沙土物理结构。其中,与CK相比,ST1处理含水率提高最多,增加41.36%;ST3处理土壤容重较CK降低最多,降低19.91%;ST4处理对风沙土孔隙度的提升最为显著,相比CK增加5.31%。煤矸石土壤调理制剂促进了沙地柳枝稷生长。与CK相比,施用煤矸石土壤调理制剂能够显著提高柳枝稷株高,其中,ST4处理对柳枝稷的株高增长效果最为显著,较CK增长54.3%;ST2处理则对柳枝稷地上生物量提升效果最为显著,ST3处理对地下生物量提升最显著,相比CK分别增长57.26%、31.47%。主成分分析结果表明,与CK相比,煤矸石土壤调理制剂处理组得分以ST2最佳,得分为0.40。因此,改善毛乌素沙地土壤性质的最佳煤矸石土壤调理制剂含量为84%。

基于工艺引擎的规划放煤控制系统

目前对综放智能化的研究主要聚焦于感知方面,对放煤过程智能化的研究较少,自动放煤控制技术存在自适应性不足、效率较低、放煤质量难以把控等问题。为了提升放煤过程的智能化水平与运行效率,设计了一种基于工艺引擎的规划放煤控制系统。该系统由放煤管控单元和窗口决策单元组成:规划放煤管控单元通过异步递进的放煤调度策略、柔性切换技术及规划放煤工艺编辑引擎,实现采煤机位置弱关联的自动顺序放煤及工艺在线编辑,通过关联后部刮板输送机负载,动态调整工艺启停,保障刮板输送机安全作业;窗口决策单元通过PID控制算法动态调节尾梁角度,实现放煤窗口反馈控制,采用遗传算法优化BP神经网络对放煤窗口大小进行智能决策,以适应不同工况,提高放煤质量。现场应用结果表明:基于异步递进的放煤调度策略与柔性切换技术提升了单刀自动运行效率,无需再手动接管;每一班组自动化运行刀数提升了33.3%;系统关联的后部刮板输送机负载、泵站等设备可动态调整工艺启停,每班后部刮板输送机平均停止次数下降了61.1%,可保障作业安全;工艺编辑引擎能适应多种场景下的应用,工艺调整用时大幅度降低;后部动作与前部动作相互叠加,使得单刀平均用时缩短了9.3%,提升了开采效率;倾角传感关联控制与规划放煤窗口智能决策将每日发热量提升了10.3%,改善了放煤质量。

新型薄煤层蓄电池支架搬运车的研制及应用

针对防爆柴油机支架搬运车难以运输薄煤层液压支架的问题,通过分析支架搬运车在薄煤层综采工作面多通道回撤工艺中的作用,确定了新型薄煤层蓄电池支架搬运车的功能参数,设计了与薄煤层支架相匹配的承载功能结构,分析了车辆轴荷分布特点及驱动模式适应性,设计了开关磁阻电机驱动系统及电回馈制动系统,分析了大容量特殊型铅酸蓄电池的充放电特性,指出了蓄电池的使用维护事项及提升续航里程的方法,介绍了车辆相关智能化配置及采用的先进技术。工业性试验表明,新型薄煤层蓄电池支架搬运车整车性能完全满足使用需求。

煤矿综采工作面本质安全型组合开关控制与仿真研究

为了保障煤矿开采工作顺利进行,设计了一种煤矿综采工作面本质安全型组合开关控制方法。从本质安全型组合开关的特性角度设计开关控制器,该控制器使用传感器收集组合开关工作数据信号,处理并计算这些信号获得组合开关工作现状,根据该现状控制组合开关的动作,根据通讯协议实现本质安全型组合开关远程控制。仿真研究表明,该方法能够降低本质安全型组合开关的谐振频率,确保开关工作电流稳定,保障煤矿综采工作面各机械设备低功耗、稳定运行。

煤矿地面供电系统的优化改造及应用分析

针对煤矿地面供电系统存在稳定性、可靠性相对较低的不足,以监测矿用供电系统所用的10 kV开关柜运行情况为研究对象,基于该种开关柜的运行特点与监测需求,为10 kV开关柜设计了运行监测系统,介绍了该监测系统的总体结构,设计了该系统的硬件部分与软件部分,进行了工业性试验。试验结果表明,应用该监测系统来监测10 kV开关柜运行情况,可精准地记录断路器机械性能与动作情况,有助于进一步了解开关柜运行情况,提升矿井供电系统工作的稳定性、可靠性。

煤矿10 kV高压开关柜智能监测系统设计与应用

针对煤矿10 kV高压开关柜监测系统功能单一、采集精度低、实时性差等问题,设计了一套基于CAN总线的高压开关柜智能监测系统。系统采用多种智能传感器对高压开关柜核心设备的温度、振动、绝缘等参数进行分布式监测,通过远程监控平台进行远程集中监测预警,有效实现对煤矿高压开关柜全方位状态监测,提高设备运行可靠性。

一种适应上升管受热变形的氨水切换装置

捣固焦炉导烟车和顶装焦炉装煤车上配备有氨水切换装置,由于焦炉使用年久后炉顶上升管受热变形,多数焦化厂反馈使用效果不佳,对此,基于氨水切换装置使用现状,设计了一种可以适应上升管变形的氨水切换装置,应用效果显著。