基于续流量校正的早期试井分析方法

目前,国内外已有很多有关早期试井资料的分析方法,文中从中优选出了一种能够更简单地解决基于常井筒存储条件下短期资料的分析技术,根据其基本公式,推导其压差、压力形式的直线方程,并求得各种地层参数。利用该校正方法,可以得到直线段出现早的分析图,揭示被井储掩盖的早期油藏动态,从而提高早期数据的利用率,测试时可以较大地缩短关井时间,使试井与生产的矛盾在一定程度上得以缓解。

ASTORIA-PACIFIC 连续流式荧光分析仪的维护保养

目的:探讨ASTORIA-PACIFIC连续流式荧光分析仪维护和保养的方法。方法:对仪器进行检测前、检测中、检测后全程维护,打破传统仪器的每日、每周、每月的维护周期和保养模式,并加强日常保养,缩短保养周期。结果:通过日常精心地维护保养,确保仪器始终处于良好的运行状态,延长仪器及其零部件的使用寿命,及时准确地报告检测结果,节约了试剂,大大提高了工作效率。结论:此方法对仪器的维护和保养适用可行,值得推广。

Thermal analysis for brake disks of SiC/6061 Al alloy co-continuous composite for CRH3 during emergency braking considering airflow cooling

The mass of high-speed trains can be reduced using the brake disk prepared with SiC network ceramic frame reinforced 6061 aluminum alloy composite （SiCn/Al）. The thermal and stress analyses of SiCn/Al brake disk during emergency braking at a speed of 300 km/h considering airflow cooling were investigated using finite element （FE） and computational fluid dynamics （CFD） methods. All three modes of heat transfer （conduction, convection and radiation） were analyzed along with the design features of the brake assembly and their interfaces. The results suggested that the higher convection coefficients achieved with airflow cooling will not only reduce the maximum temperature in the braking but also reduce the thermal gradients, since heat will be removed faster from hotter parts of the disk. Airflow cooling should be effective to reduce the risk of hot spot formation and disc thermal distortion. The highest temperature after emergency braking was 461 °C and 359 °C without and with considering airflow cooling, respectively. The equivalent stress could reach 269 MPa and 164 MPa without and with considering airflow cooling, respectively. However, the maximum surface stress may exceed the material yield strength during an emergency braking, which may cause a plastic damage accumulation in a brake disk without cooling. The simulation results are consistent with the experimental results well.

Simulation and design of a self-heating continuous-flow PCR chip

A novel continuous-flow PCR chip adopting self-heating, passive-cooling mode to realize the DNA fragments amplification was presented. Using the ANSYS finite element analysis, the temperature distribution of the chip is simulated and analyzed.The optimal size of the chip is 30×22 mm2, the roundabout micro-channel is the 90 μm width, 40 μm depth. Two micro-heater with the nickel-chrome alloy material film are formed on the side of silicon belonging to denaturation and renaturation zones needed for PCR reaction, and two adiabatic structures with groove on side of silicon by anisotropy etching. By the mode of heating local zones at single side, three wider constant temperature zones could be formed, which are 60 ℃,72 ℃,95 ℃ and suitable for PCR,and the temperature-difference could be restricted in less than 5 ℃.

Sustainability Assessment and Ranking of Run of the River(RoR) Hydropower Projects Using Analytical Hierarchy Process(AHP):A Study from Western Himalayan Region of India

In the present scenario,tapping the unutilised hydropower potential is one of the highest priorities in developing countries of the world.Special emphasis is being imparted to run of the river(RoR)mode of power generation.However,the governments are now facing the dilemma whether to promote small hydropower projects(SHPs) or encourage large hydropower projects(LHPs).RoR large hydropower projects result into large scale cutting of mountains for constructing tunnels and access roads,generation of huge quantity of muck and large scale impact on flora and fauna due to diversion of rivers/streams.On the other hand,though SHPs are claimed to be greener and more sustainable by a section of researchers and energy planners but,they will be required to be set up in large number to generate equivalent amount of electricity.The aim of this study is to rank the most sustainable installed capacity range of RoR hydropower projects.To achieve this aim,the study proposes the use of quite popular multi-criteria decision making(MCDM)method of Operation Research named Analytical Hierarchy Process.A case study has been presented from Himachal Pradesh,a hydro rich state located in the western Himalayan region.As per sustainability assessment carried out in this study,hydropower projects in the capacity range 1 to 5 MW have been ranked to be the most sustainable.

Is Terzaghi's effective stress a stress variable under seepage conditions?

From the continuum mechanics perspective, an attempt was made to clarify the role of Terzaghi's effective stress in the theoretical analysis of saturated soil subjected to seepage. The necessity of performing a coupled hydromechanical analysis to solve the seepage-deformation interaction problem was illustrated by examining the equations of static equilibrium among the effective stress, seepage force, pore-water pressure and total stress. The conceptual definition of stress variable that satisfies the principles of continuum mechanics is applied in the coupled hydromechanical analysis. It is shown that Terzaghi's effective stress is in fact not a stress variable under seepage conditions, and the seepage force acting on the soil skeleton cannot be viewed as a body force. This offers a clue to the underlying cause of a paradox between the real Pascal's hydrostatic state and the hydrostatic state predicted by a class of continuum hydromechanical theories.