海城仙人洞遗址出土钻器的实验研究

本文运用实验考古学方法，在模拟制作和使用脉石英钻器的基础上，记述了用脉石英钻器钻孔所产生的使用微痕的特点，并讨论了制作疤与使用微痕的区别，进而对海城仙人洞遗址出土的从形态上鉴定为钻器的标本做微痕观察和分析，结果表明它们中的一部分所见使用微痕基本具有钻孔形成的特点，因而这部分石器的功能应该是钻，是名符其实的钻器．

密集多头钻器的设计开发

介绍了密集型多轴头钻器的设计开发，实现了在改装的普通机床上就可达到专机加工的生产效率，以较少的投入达到了较好的效果。

液压抵钻器在使用过程中存在的问题及对策

在联接钻机跑车的液压操作阀的液压油管上串入三通和闸阀,再与液压抵钻器进行联接,当钻机矛头退尺时,利用液压抵钻器抵住钻杆能够防止钻杆因自重而下滑,能够实现钻机矛头安全退尺,防止损坏水笼头,提高钻孔施工效率。

Optimization Design and Finite Element Analysis of Core Cutter

The hydro-hammer sampler is a new type of sampler compared with traditional ones. An important part of this new offshore sampler is that the structure of the core cutter has a significant effect on penetration and core recovery. In our experiments, a commercial finite element code with a capability of simulating large-strain frictional contact between two or more solid bodies is used to simulate the core cutter-soil interaction. The effects of the cutting edge shape, the diameter and the edge angle on penetration are analyzed by non-liner transient dynamic analysis using a finite element method （FEM）. Simulation results show that the cutter shape clearly has an effect on the penetration and core recovery. In addition, the penetration of the sampler increases with an increase in the inside diameter of the cutter, but decreases with an increase in the cutting angle. Based on these analyses, an optimum structure of the core cutter is designed and tested in the north margin of the Dalian gulf. Experiment results show that the penetration rate is about 16.5 m/h in silty clay and 15.4 m/h in cohesive clay, while the recovery is 68% and 83.3% resoectively.

Drillhole high-pressure packer permeability test for underground powerhouse in Pushihe pumped storage hydro-plant

Usually the water head of the pumped storage hydro-plant is high, generally up to 400-500 m, therefore the rock mass under the high-pressure bifurcation pipe have to bear as high as millions Pascal water pressure, in according with the requirements of high water head pumped storage hydro-plant should be 1.2 times of the water head special high-pressure packer permeability test compared with normal to test the permeability of rock and rock cleavage pressure value. The test results on the choice of design options often play a decisive role. Based on the engineering practice, the authors studied the drillhole high-pressure packer permeability test in the pumped storage hydro-plant's underground powerhouse, by the analysis of test results, this article offers a demonstration of the deformation of rock fracture witch under building in the condition of high-pressure water head, it provides a more detailed engineering geological background.

Application and development of numerical simulation for under- ground horizontal directional drilling

In coalmines of China, horizontal directional drilling （HDD） is an increasingly popular method for underground in-seam gas drainage. Numerical simulation, especially finite element analysis, is often used as an effective method to improve HDD operation. These improvements focus on rock-breaking efficiency, directional precision, stability of the borehole wall, and reliability of the drill equipment. On the basis of underground drilling characteristics, typical numerical simulation exam- ples in drilling techniques and equipment are summarized and analyzed. In the end, the future development trends of numerical simulation in underground in-seam drilling are proposed.

Development of experimental apparatus about reverse circulation bit

A set of experimental apparatus on reverse circulation bit are developed, in order to lucubrate the mechanism of the new type reverse circulation bits, and the structure of the bits influencing the ability of taking core and carrying powder.Both the major structure of the equipment and the procession of experiment are described.

Research on experiment and calculation of foam bursting device

This research presents experimental data on mechanical foam bursting device,based on the high speed of air fluid impinging insidethe foam bursting device,foam bubbles disrupted as a consequence of pressures changed very quickly as shear force and their impact forces.Experimental data on foam-bursting capacity have been presented.Designed device can provide effective foam bursting on collapse foam.

Application on drilling parameter monitor in drilling engineering monitoring

The drilling parameter monitor is an important tool in drilling engineering applied to monitoring drilling process,carrying out scientific analysis and decision--making.Based on discussing the present development situation of the domestic and foreign drilling machine parameter monitors,the metering scheme for vehicle--loaded drilling parameter monitor was designed.By using detection system for MSP430 single--chip microcomputer(SCM) in combination with peripheral circuit such as sensors,the drilling--rig control system was obtained to detect,and for every parameter in real--time display in order to keep operating the drilling rig status.The experiment shows that the drilling parameter monitor reaches design requirements and can be applied to drilling engineering monitoring,which has characters such as simple structure,high credibility and low cost.

ASME Section Ⅲ Stress Analysis of a Heat Exchanger Tubesheet with a Misdrilled Hole and Irregular or Thin Ligaments

A stress analysis is described for a nuclear steam generator tubesheet with a thin, or irregular ligament, associated with a mis-drilled hole using the rules of ASME （American Society of Mechanical Engineers） B ＆ PV Section Ⅲ and non-mandatory Appendix A, Article A-8000 for stresses in perforated flat plates. The analysis demonstrates the proper application of the NB-3200 rules for this special application, with discussion of the differences between an actual tube hole deviation and what is assumed in ASME Appendix A. This is a companion paper to ＂Technical Justification Supporting Operation with a Tube Installed in a Mis-Drilled Hole of a Steam Generator Tubesheet＂.

Cutting Characteristics of CFRP Boards Using Electroplated Diamond Wire Tools

CFRP （carbon fiber reinforced plastic）, which is composed of carbon fibers in a resin matrix, is an extremely strong and light composite material that has found use in the aerospace and automotive industries. CFRP boards are very difficult to machine using common machining processes. Various machining artifacts, such as burrs and delamination, occur frequently when machining CFRP. Adequate techniques for machining CFRP have not yet been established. Recently, electroplated diamond wire machining technology has found use in cutting hard, brittle materials such as silicon and sapphire. In this study, we used an electroplated diamond wire saw to cut a CFRP workpiece. We quantified the cutting forces imposed on the workpiece and observed the surface state of the workpiece after cutting. We demonstrated that an electroplated diamond wire tool is suitable for the high-quality machining of CFRP boards.

A Numerical Model of a U-Tube Vertical Ground Heat Exchanger Used as an Evaporator

The paper presents a general distributed model of a vertical U-tube direct expansion heat exchanger coupled with the ground. This model is developed for studying the dynamic thermal behavior of a buried heat exchanger which is an integral part of a so-called direct expansion heat pump. The transient conservative equations of mass, momentum and energy considering single and two-phase flow of refrigerant are derived and presented. The diffusive heat exchange with the ground is treated using an analytical approach to treat short-time scale response of vertical boreholes based on an imposed temperature. The thermal interference between the two pipes of the heat exchanger is also considered. The mathematical equations of the model are numerically presented using a control volume formulation and the solution of the system of equations is obtained by successive iterations. The dynamic behavior of the evaporator is simulated and the numerical results are analyzed regarding spatial parameters distribution and thermal interference influence.

Development of a six drillhead roof bolting machine

In underground mining, machine design is predominantly dictated by mine conditions and individual customer desires. In partnership with Foresight Energy, J. H. Fletcher & Company was tasked to design and manufacture a new roof bolting machine with six independent drilling apparatus on board capable of drilling and bolting the roof and ribs with material handling. The objective was to produce a machine capable of drilling and installing six bolts simultaneously with a limited number of operators. The goal of the mine is to decrease the time to bolt a cut to improve the safety level of the current roof bolting method, improve efficiency and to improve the bottom line cost of entry development. The customer wanted four drills at the front of the machine dedicated to installing roof bolts and then another two drills behind them dedicated to rib bolts. This dictated the requirement of latched controls, which would allow the operator to start drilling one hole and then latch the controls to be able to move on to the next.The result of the design is a machine with a single platform and six independent masts with drillheads:four masts strictly for drilling and installing roof bolts on the front of the platform and two masts on the back of the platform for rib bolts. The controls at each operator's station include a latch control for drilling. The six-head roof bolter allows fewer operators to drill and install roof and rib bolts, which in turn lowers the miners' roof exposure per cut. This design reduces the operator's exposure from the inherent pinch points and rotary hazards once he has engaged the latch drilling. Therefore, the machine will help to decrease the time to bolt a cut, improving productivity while enhancing the ability to operate the machine safely.

Experimental and Parametric Design of Petroleum Back-pressured Hydraulic Impactor

Percussive-rotary drilling technology was considered many years ago as one of the best approaches for hard rock drilling. It is a key for popularizing this technology on a large scale to design and make an impactor with excellent performance. This paper presents a suit of method to design the percussive parameters for the oil or gas field by introducing the working principle of back-pressurod impactor, dividing the working periods of impaetor into three phases and establishing the computer emuiational model of percussive parameters. It draws a comparison between the results of model calenlation and experiment on the basis of analyzing the experiment results of impactor. The conclude provides credible foundation for designing and further ameliorating the impactor.

CAx Process Chain for Automated Laser Drilling of Tool Molds

Rotation sintering, also known as slush molding, is used to manufacture molded skins, such as dashboards or door interior panels for cars. At present, approximately 80% of such molded skins are manufactured using electroforms to achieve the complex free-form surfaces, and surface structures, such as leather graining that the industry demands. The manufacture of these electroforms is, however, time-consuming and expensive. This project aims to replace conventional electroforms with laser-drilled molds. Holes in tool molds should be drilled by using laser radiation as part of an automated process. The system consists of a robot with a fiber-laser beam source. A CAx （computer-aided x） process chain has been developed for this purpose in which the CAD （computer-aided design） data of the tool molds are processed, drill hole fields generated, and a machine-specific RC （robot control） program created. Process-specific fundamentals, such as suitable process windows and process control, have been devised to manufacture holes using fiber laser radiation The advantages of the new laser-drilled tool molds may result in substituting them for conventional electroforms, allowing old markets to be re-entered or additional markets to be created and targeted through new molds or lower costs.

Improvements of drilling fluid processing for cable-suspended electromechanical drills

Deep ice drilling in Polar Regions plays a key role in paleo-climate, microbiological and glaciological researches. For deep ice and subglacial coring the special purpose-built electromechanical cable-suspended drills with bottom-hole circulation are designed and explored. Used at present drilling fluid circulation systems are specified by very high fluid wastes during processing. Measurements in deep drilling projects in Antarctic and Greenland ice sheets showed that 25%-40% of the drilling fluid, pumped into the hole, is retrieved to the surface with cable and drill, and up to 45% of retrieved fluid goes to waste. This leads not only to increasing of the fluid consumption and cost of the project in general but also to severe contamination of air, surface and near-surface snow-firn layers at the drilling site. In order to reduce wastes and environmental impact, it is proposed to modify drilling fluid processing system by avoiding of evaporation and leakages of fluid as far as practicable. Drilling fluid is prepared and pumped into the hole according to predetermined program on semiautomatic mode, and volume and density of blended and pumped into the hole drilling fluid are measured continuously. Components of the drilling fluid are stored and mixed in the special closed containers equipped by pressure relief valves. Separation of drilling fluid from ice cuttings is carried out by two steps: firstly, fluid is separated with hydro extractor and then with thermal separator. To reduce the amount of removed drilling fluid with cable special squeezing collar is installed on the borehole mouth. All these arrangements are able to decrease drilling fluid wastes in many times.

Design of Hybrid Compensators for Power Quality Improvement of Oilfield Drilling Electrical System

With large-scale use of kinds of motors, oilfield drilling electrical system always accompanied by serious power quality problem, including reactive current, harmonics current and grid voltage distortion, which would greatly threaten the safety and proper working of the whole system. This paper focuses on a power quality improvement project to solve these problems. A hybrid compensating scheme, including an active compensator and a passive compensator, is carried out. Because of the specificity of oilfield drilling electrical system, compensators are redesigned against features of this application background. And then the current detection point arrangement of this hybrid system is also taken into consideration to build the whole system much more effective and reliable. Now the improvement project is already implemented in application field, and the power quality of the system is greatly improved.

A novel method of removal of a broken drill bit in the femoral medullary canal during internal fixation of a type C distal femoral fracture： a case report

Breakage of surgical instruments and implants during operative procedures is not uncommon in any surgical discipline. The need for removal and the out come of leaving the broken instruments and implants in the surgical area have not been described in detail. Few studies have suggested removal if they are lying loosely in the tis sues or joint, close to neurovascular structures. Challenges and the amount of time spent in the retrieval of broken instruments and implants are well most choose to leave them in known among surgeons, so situ. We reported a novel method of retrieval of a broken drill bit in the femoral medul lary canal during internal fixation of a type C distal femoral fracture.