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The mechanization, greening and intelligent construction technology of the patio has become the main trend of technological development. This is also one of the key tasks to promote the high-quality development of metal mines. The mining of metal mines is gradually moving towards deeper areas, and the complexity of geological conditions such as high ground pressure, high ground temperature, and high-water pressure, as well as the uncertainty of the operating environment, are becoming increasingly prominent. These bring great difficulties and challenges to the construction of various raiserockhole projects serving mine production. The types of raiserockholes were comprehensively reviewed in metal mining, and the existing mechanical rock-breaking drilling processes for vertical raiserockhole, inclined raiserockhole, and cutting groove (blind raiserockhole) were analyzed. By analyzing the status and challenges faced by existing cutting groove drilling rigs and raise boring machine, the key technologies for intelligent drilling of cutting groove drilling rigs and raise boring machine have been analyzed from the aspects of efficient drilling, intelligent control, surrounding rock control, and intelligent equipment. In response to the insufficient one-time drilling capacity of existing raise boring machines for large diameter and high to medium section shafts, as well as the high deformation of fractured and weak surrounding rocks, which can easily lead to instability and collapse of the raiserockhole. A new construction technology for the integration of drilling and support with large diameter raise boring machines in poor strata has been proposed. Focusing on key technologies such as mechanical rock breaking and positive boring, full-section equipment intelligent boring, equipment matching and safe suspension, and the starting and dismantling of the raiserockhole boring machine, the research and development direction of the raiserockhole boring machine drilling technology has been analyzed. The aim is to provide a reference for the development of safe, efficient, green and intelligent construction technology for metal mine mining. [ABSTRACT FROM AUTHOR]

In view of the underwater single wall steel pile cutting operation requirement, the underwater hydraulic drilling and milling cutting machine was designed and manufactured. The end milling cutter was used as the cutting tool, and the hydraulic cylinder feeding, hydraulic motor driving milling cutter drilling and milling and rotary cutting were used. The design basis and components of the equipment were described in detail. The parameters selection of drilling and milling cutter, drive motor and transmission system was analyzed, and a prototype was made according to the design scheme. Through the offshore and workshop tests of the underwater hydraulic drilling and milling cutting prototype, the reliability of the equipment was verified, and the cutting efficiency and milling cutter consumption parameters of the prototype were obtained. The actual test shows that the equipment is reliable, and the equipment has low processing, use and maintenance costs, which is suitable for underwater single wall steel pile cutting promotion. [ABSTRACT FROM AUTHOR]

Copyright of Tunnel Construction / Suidao Jianshe (Zhong-Yingwen Ban) is the property of Tunnel Construction Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Uranium Geology is the property of Uranium Geology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Railway Investigation & Surveying is the property of Railway Investigation & Surveying Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Hangzhou Bay Sea-Crossing Bridge for the Nantong-Suzhou-Jiaxing-Ningbo Railway will be the longest seacrossing high-speed railway bridge with the highest construction standards in the world after its completion. The construction conditions in this area are harsh, and the borehole depth is great, demanding higher verticality. In order to ensure the engineering quality, the "dynamic to static" coupling dual platform independently developed by CCCC Third Harbor Consultants Co.,Ltd. is adopted, and it can effectively reduce the impact of surge waves on the stability of the exploration platform and the deviation of the opening of boreholes. SH-G3 borehole trajectory detector is used to detect the verticality of the boreholes. By comparing the testing results of borehole verticality by different drilling techniques, the influencing factors on drilling verticality in offshore exploration are analyzed. The results showed that, regardless of the geological factors, when a drilling rig adopts integrated drilling technique such as medium-speed gear drilling, ø50 mm drilling rods and longer coring sampler, the drilling deflection may be greatly reduced and the borehole verticality may be much improved in offshore exploration, providing more accurate survey results for engineering construction projects. [ABSTRACT FROM AUTHOR]

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Copyright of Journal of China University of Petroleum is the property of China University of Petroleum and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Copyright of Journal of China University of Petroleum is the property of China University of Petroleum and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Copyright of Wool Textile Journal is the property of National Wool Textile Science & Technology Information Center and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Throwing device is an important factor that directly affects the performance of chaff cutter. For the problem of low throwing efficiency and residue blockage of disc knife chaff cutter, scholars at home and abroad have done a lot of research, but most of the previous research is based on simulation and experimental research. For the movement of materials, theoretical analysis studies are rarely performed. Most scholars only analyze the movement of material in the throwing device separately, and ignore the influence of the front-end device and airflow on the material. Therefore, this study aims to establish a more complete theoretical analysis model to provide a theoretical basis for the design of the whole machine of the chaff cutter. A kinetic analysis method was proposed to reveal the laws of material throwing motion of the disc knife maize. Material movement process were divided into seven stages in the whole throwing process, according to the matching between the throwing device and the front-end device, and the influence of airflow on the material. The movement and force of the material were analyzed in each stage. The kinetic model of the material movement along the throwing blade, along the throwing straight and elbow, and after throwing out of the outlet was established, using the initial and final velocity of each stage to connect adjacent stages. Based on the dynamic model, the throwing distance of the material was taken as index value, and a numerical calculation model was established using MATLAB software. The parameters related to the maize straw material involved in the simulation and calculation process, including moisture content, mass and diameter, were measured by physical tests. The airflow velocities in the throwing tube at different working conditions were measured using a TSI9565 anemometer, and the average value (0.203) of the coefficient of friction between the maize straw material and the tube wall was obtained using a CNY-1 inclinometer. The parameters of simulation model were determined according to the actual structural parameters of the 9Z-6A disc knife chaff cutter and the test data related to the maize straw material, and the influence of the spindle speed and blade inclination angle on the throwing performance was analyzed. The results showed that the throwing distance increased approximately linearly with the increase of the spindle speed during the test range. The throwing distance first increased and then decreased, with the blade inclination angle increased. The maximum throwing distance was obtained when the length of the shredded material was 12 mm, the blade inclination angle is 7° and the spindle speed was 700 r/min. The results obtained from the throwing distance test were consistent with the trend of the theoretical simulation results, with a maximum relative error of 6.6%, which verified the accuracy of the dynamic model. The findings can provide a theoretical basis for the structural design, parameter optimization, and matching of the chaff cutter. [ABSTRACT FROM AUTHOR]

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Tunnel Construction / Suidao Jianshe (Zhong-Yingwen Ban) is the property of Tunnel Construction Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

For the problems of the well deflection, hole enlargement, bit whirl and vibration, and the bit early failures caused by the unbalanced forces on PDC bits during the drilling processes, the optimal design model of cutter-layout of global force balanced PDC bits and bending moment model were constructed based on the existing PDC bit cutting mechanics, and the corresponding solution method was proposed. Results of a cutter layout design example show that the global force balance cutter layout design method may keep the global force balanced status of PDC bits in different footages. In particular, the force balance state of PDC bit is greatly improved at small footage(<1 mm). The drilling stably of PDC bits is improved. The results are of great significance to amend the forces on drill bits, which may extend the service life of the drill bits and improve the drilling efficiency. [ABSTRACT FROM AUTHOR]

In order to solve the problems that the surface unevenness leads to the tilt of the seed feeding device of centralized metering device in rapeseed mechanized seeding, which causes insufficient seeding stability, the seed feeding device of centralized metering device was taken as the research object, the working process of the seed feeding device was analysied and the mechanical models between rapeseed and the type hole of the seed feeding device were built at different lateral tilt angle during the seed filling, seed carrying and seed dropping process. The effects of lateral tilt angle perpendicular to work direction and rotating speed of seed feeding device on seeds quantity in type hole and seeds migration trajectory during seeding process were analyzed by EDEM simulation. The simulation results showed that with the increase of the tilt angle within 0°-5°, the average increase of seed quantity in type hole of the tilt side relative to the no tilt increased within 0-36.55%, and the average decrease of seed quantity in type hole on the other side relative to the no tilt decreased within 0-26.68% during seed filling and seed carrying process. The ratio ranged from 1.02 to 2.70 between the highest seed quantity of type hole 1 and the lowest seed quantity of type hole 4. During the process of seed dropping, when the rotating speed of seed feeding device was fixed, with the increase of lateral tilt angle ranged from 0° to 5°, relative to the no tilt state, the average seed quantity increase of seed dropping port I was 0-86.82% and the average seed quantity decrease of seed dropping port II was 0-75.65%, respectively As the rotating speed of the seed feeding device was 20 r/min and 40 r/min, the ratio of seed quantity of seed dropping port I to that of seed dropping port II was 14.4 and 5.29, respectively. The intelligent test platform of planting machines was used to test the effects of different lateral tilt and swing on seeding performance of the seed feeding device. The experimental results indicated that the average error of seed quantity between the bench test and simulation test was 3.86%, which showed that the simulation results were reasonable and credible. With the increase of the absolute value of the lateral tilt angle, the increase of the total seeding rate was 0.76%-8.72% compared with the total seeding rate without tilt. With the increase of the absolute value of the lateral swing angle, the change of the seeding rate of the seed dropping port I and II was 0-55.61% compared with the no tilt state, and the increase of the total seeding rate was 0.65%-4.23%. With the increase of lateral reciprocating swing, the increase of total seeding rate was 1.12%-9.02% compared with that of no tilt state. The test results showed that lateral tilt, lateral swing and lateral reciprocating swing had significant influence on seeding stability. The effects of lateral tilt and swing on seeding performance could be reduced by increasing the rotating speed of the seed feeding device. The results can provide reference for promoting the structure improvement and performance improvement of the seed feeding device. [ABSTRACT FROM AUTHOR]

Combineding with the ridge planting mode of carrot in Shandong and other places, this research developed a air-suction precision carrot seeder which integrated the functions of ridging, ditching, precision sowing, covering soil and pressing was developed. The machine was mainly composed of air-suction precision metering device, ridging and shaping device, ditching and seed dividing device, soil covering device, frame and transmission system. According to the analysis of the force and movement of seeds in the process of seed suction and seeding, the critical value of vacuum degree in the air chamber of seed metering device was obtained, and the main influencing factors of seeding position and plant spacing uniformity were determined. A seed-metering plate with double-ring type hole was designed, the radius of the inner and outer circle holes of the seed-metering plate was 87.5 and 95.0 mm respectively, and the number of holes in each circle was 30. According to the requirements of seed cleaning and working space, the upper scraper removed the excess seeds adsorbed on the upper side of the inner and outer ring type holes, the zigzag structure was adopted. The lower scraper removed the excess seeds adsorbed on the lower side of the inner and outer ring type holes, and the eccentric structure was used. According to planting agronomic requirements, the FL-2.5 fan was determined to meet the requirements of different sowing air volume. Three double-wing ridging plows were used to ridge, and the ridge shape was trimmed by a shaping device to complete 2 trapezoidal ridges at one time. According to the requirements of double narrow row, shallow ditching and less covering soil, the structure of ditching and the parameters of overburden were determined. According to the analysis of the seed feeding process, the low-level seed feeding mode was adopted, and the seed metering the overall height of the ditching and seed separation device was about 100 mm. Taking the type hole diameter of the seed-metering plate, the rotating speed of seed-metering plate and the negative pressure of the air chamber as the test factors, and taking the eligible rae of seed spacing, the missing rate and the multiple rate as the test evaluation indexes, three-factor and five-level orthogonal experiment was carried out. The best working parameter combination for seed-metering device was abtained: the type hole diameter was 1.6 mm, the rotating speed of seed-metering plate was 18 r/min, and the negative pressure of the air chamber was 4.4 kPa. The field sowing experiments were carried out at working speeds of 3, 4 and 5 km/h respectively. The experiment results showed that with the increase of working speed, the eligible rate changed little, the multiple rate decreased, and the missing rate increased, but the overall scope of change was not large, the eligible rate was more than 94%, the missing rate was less than 5%, and the multiple rate was less than 4%, the working performance of the machine met the national standard and the requirements of carrot planting agronomy. The study can provide reference for the design of precision seeder for small seed vegetables such as carrot. [ABSTRACT FROM AUTHOR]

Copyright of Journal of China University of Petroleum is the property of China University of Petroleum and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Aiming to solve the problem of abnormal missing holes occurred in 3D reconstruction mesh models frequently, this paper proposed a novel method that hole-defect identification automatically and detail-preserving surface repair around the hole. Firstly, in order to determine whether the hole was a real defective hole, it detected the context irregularity and contour irregularity of the missing region. After that, it detected and matched the feature lines around the hole, which were to form the fundamental surface of the hole area, and then it introduced unconstrained triangulation for basal surface. Finally, it made use of the anisotropy of mesh to refine and adjust morphologically to improve the topological and geometric properties of the mesh. The experimental results show that the proposed method can identify the defective hole and restore the hole area' s detail features of triangular mesh models effectively. [ABSTRACT FROM AUTHOR]

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Natural Gas Industry is the property of Natural Gas Industry Journal Agency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Experimental Technology & Management is the property of Experimental Technology & Management Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper, supercritical carbon dioxide was used as an extracting agent to recovery the oil from the oil-based drilling cuttings. By setting the residual oil contents as the main evaluation index, the effect of several factors including extracting pressure, extracting temperature, and extracting time were investigated. The results showed that the residual oil content was 0.748% when the extracting pressure was 25 MPa, the extracting temperature was 50°C, and the extracting time was 100 min. This extraction technology shows a favorable treatment efficiency. [ABSTRACT FROM AUTHOR]

High-strength carbon fiber reinforced polymer (CFRP) with unidirectional laminate structure has gradually developed into major material in load-bearing components in aerospace, and the cutting demand of CFRP is increasing. Because of the significant anisotropy, CFRP laminates highly tend to produce defects and are typical difficult-to-machine materials. Orthogonal cutting experiments on T800 high-strength CFRP unidirectional laminates are conducted to study the variation of cutting force, torque and cutting temperature with different fiber orientations. Based on the drilling experiments with brad point drill and multifacet drill, the effects of cutting force, torque and cutting temperature on defect forming process are discussed, and SEM topography of hole wall surface with typical defects is given. Through analyzing the wall surface of drilling holes, defect formation mechanism under different drilling processes is given. [ABSTRACT FROM AUTHOR]

The powder of persimmon peel was used as water-based drilling fluid addictive, and he performance of it was evaluated. The results showed that persimmon peel performed a great effect of reducing fluid loss, and with the treatment temperature increasing, apparent viscosity and plastic viscosity was firstly increased, then reduced, and finally increased, the filtration reduction weakened and invalided above 150 °C. The results of linear bentonite swelling experiment and mud ball experiment presented that water extract of persimmon peel can inhibit hydration and swelling of clay along with the concentration, excelled to that of 4%(wt) KCl solution. The results of compatibility with common drilling fluid additives showed that the viscosity and filtration reduction increase along with the treatment temperature increasing companying with modified starch, while the compatibility with polyacrylamide is poor, especially, the viscosity drops suddenly (from 30. 0 mPa • s to 4. 0 mPa • s) at 120 °C and filtration reduction is invalid. [ABSTRACT FROM AUTHOR]

Combining with the engineering geological conditions and water-inrush features of auxiliary shaft in Niaos-han Coal Mine, comprehensive treatment scheme for water-inrush control and side wall restoration was put forward under the principle of "grouting to target and control after locating". As the precondition of water-inrush control that the source and passage of water-inrush were ascertained by SYT and mine transient electromagnetic method, and controllable draining was accomplished first in order to ensure the safety of shaft lining and grouting, then replacement grouting on working face was put into effect after backwall grouting achieved sectionally, diffusion region of which was umbrella distribution. The scheme studies and confirms the arrangement of grouting holes, slurry matching and construction technology that conforms to the principle of "grouting after reinforcement and moderately leak when grouting" to ensure the success of backwall grouting, after that, according to the stress characteristics, a late-model grouting pad under water that consists of under filtering layer and upper concrete layers was put forward to maintain shaft lining and displace sludge. The techniques that dredging and water plugging on the working face in shaft combine with backwall grouting have remarkable technical and economic benefit, and are practical experiences for the rapid and safety construction of deep vertical shaft. [ABSTRACT FROM AUTHOR]

In order to study the compositional change of residual gas during different desorption stages, refined desorption experiments of nine freshly anthracite samples, collected from the drilling wells and coal mines in Zhina, Guizhou, were carried out, and the gas compositions were determined by gas chromatography(model SP-3400). It was found that the desorbed gas volume is largest at crushed desorption stages, indicating that most of the residual gas is trapped in closed coal pores. Methane, carbon monoxide, carbon dioxide and ethane concentrations show a V-type change and are lowest at crushed desorption stage, whereas nitrogen concentration gives anti-V type trend and is highest. A remarkable compositional fractionation of each component occurs during heated desorption after crushing, showing the progressive enrichment of carbon monoxide, carbon dioxide and ethane, and relatively depletion of methane and nitrogen. It was suggested that the fractionation effect is derived from the differences of adsorption temperature and adsorption capacity, resulting in more retention of the gas components with higher adsorption capacity in micropores after desorption at the room temperature, and then desorption at the higer temperature 90-95 °C of water bath heating. [ABSTRACT FROM AUTHOR]

Hydraulic cutting seams pre-extracted technique used in coal seam is an effective means to prevent and control coal and methane outburst which is the dominating dynamic disaster in coal mine. However, transient process appeared in transition of drilling to cutting in hydraulic cutting seams system may sensitively cause coal and methane outburst occurrence. Depending on transient process pressure and discharge control problem of hydraulic cutting seams system, experimental methodology was employed to systematically investigate transient characteristics of independent designed and manufactured key device of hydraulic cutting seams and the key structure influence of cutting device was analyzed. Experimental results show that there is little effect on transient pressure by diameter and number of nozzle and is stabilized on about 1.1 MPa, linear trend of net discharge which could predict transient pressure is fitted, 9.3% is the prediction maximum errors; various kinds of valve element parameters impact transient pressure are different and not uniform, parameter of up-orifice diameter is the primary discharge manipulative constant while transient pressure do not vary with valve element area. [ABSTRACT FROM AUTHOR]

On account of the coal mine gas drainage holes can not be precise and quick orientation before drilling, a new method using the fiber optic gyroscope(FOG) inertial navigation technology was proposed to achieve accurate and fast orientation of drilling machine. According to the motion characteristics of drilling rig attitude adjusting process and measurement requirements, the drilling directional instrument measuring overall scheme was designed, using information of velocity and position to restrain the measurement error which was drifted by time. The Kalman fiter (KF) was designed to realize the measurement precision for long time. The principle prototype was realized by designing hardware and software of the system. The correctness of the method was verified through the designed prototype testing. The experimental results show that north finding time, accuracy, system precision of dynamic and static long time measurement meet the using requirement. FOG-based Directional Instrument provide a new idea for positioning and orientation instruments developed in the coal field. [ABSTRACT FROM AUTHOR]

In the abstracting and exploitation process of coalmine gas (coalbed methane), the drilling fluid should maintain the borehole stability and lower the damage to coal reservoir simultaneously. Using original coal rock(simulating compact coal rock) and man made coal rock (simulating incompact coal rock or coal rock with big crack), authors appraised the temporally plugging and unplugging performances of degradable drilling fluid to coal rock during the sequent stages such as the initial stage, polluted stage, unplugging stage by enzyme and unplugging stage by low concentration HCl. The onsite implement technology was also discussed. The results show that firstly degradable drilling fluid can maintain borehole stability during coal drilling. Then, the technologies of soaking enzyme and low concentration HC1 successively can remove the damage caused by polymers and carbonate rocks. Furthermore, absence of enzyme or HCl will lead a lower unplugging performance. Thirdly, the concentration of carbonate rocks in the coal rock and degradable drilling fluid determines the unplugging performance of low concentration HCl. Fourthly, the gas permeability of coal rock can be improved by heat treatment. Finally, the onsite implement technology is feasible and field trial should be carried out in coalbed methane drilling. [ABSTRACT FROM AUTHOR]