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Effects of submerged flexible vegetation and solid structure bars on channel bed scour

International Journal of Sediment Research 2012年第3期27卷 323-334+336+335页

作者： Su-chin CHEN Yi-ming KUO Hsiao-chia YEN Dept.of Soil and Water Conservation National Chung Hsing Univ. Dept.of Design for Sustainable Environment Ming Dao Univ. Soil and Water Conservation Bureau Council of Agriculture

The effects of different submerged obstacle longitudinal bars with different arrangement densities on the flow profile and morphology of a scour hole were investigated under clear water conditions. Acoustic Doppler velocimetry(ADV) data were applied to plot the vertical distributions of three-dimensional velocities and turbulent *** experimental results indicate that arrangement density(also can represent porosity),structural material(flexible or solid),and the sidewall effect are the main factors impacting turbulent kinetic energy and the morphology of scour *** flexible vegetation,the maximum turbulent kinetic energy near the bed surface increased with the arrangement *** the same structure,the depth and the magnitude of the lateral expansion of the scour hole also increased with the arrangement *** flexible vegetation reduced the depth of the scour hole because of deflection and arrangement *** larger volumes of scour found in the upstream and middle sections of solid structures compare well to those in flexible *** deflection of porous flexible vegetation transported the turbulent kinetic energy downstream,reduced the turbulent kinetic energy near the sediment bed,and increased the stability of the *** vegetation bars are able to protect the bank and the bed of a river under normal conditions,making them a good alternative design in the management and restoration of rivers.

关键词： Flexible vegetation solid structure Local scour Longitudinal bar Turbulent kinetic energy

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Ensuring the possibility of using thorium as a fuel in a pressurized water reactor(PWR)

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Nuclear Science and Techniques 2021年第12期32卷 37-52页

作者： Mohamed Y.M.Mohsen Mohamed A.E.Abdel-Rahman AAbdelghafar Galahom Nuclear Engineering Department Military Technical CollegeKobry ElkobbahCairoEgypt Higher Technological Institute 10th of Ramadan CityEgypt

The possibility of utilizing thorium as a fuel in a pressurized water reactor(PWR)has been proven from the neutronic perspective in our previously published work without assessing the thermal hydraulic(TH)and solid structure ***,the TH and solid structure performances must be studied to confirm these results and ensure the possibility of using a thorium-based fuel as an excellent accident-tolerant *** TH and solid structure performances of thorium-based fuels were investigated and compared with those of UO_(2).The radial and axial power peaking factors(PPFs)for UO_(2),(^(232)Th,^(235)U)O_(2),and(^(232)Th,^(233)U)O_(2)were examined with a PWR assembly to determine the total PPF of each *** Gd_(2)O_(3)and Er_(2)O_(3)were tested as burnable absorbers(BAs)to manage the excess reactivity at the beginning of the fuel cycle(BOC)and reduce the total ***_(2)O_(3)resulted in a more significant reduction to the total PPF and,therefore,a greater reduction to the temperature distribution compared to Gd_(2)O_(3).Given these results,we analyzed the effects of adding Er_(2)O_(3)to thorium-based fuels on their TH and solid structure performances.

关键词： Thermal hydraulic(TH) solid structure Thorium-based fuel Gd2O3 Er_(2)O_(3)

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Research and Implementation of a New Orientation ＆ Incline Instrument Used in Oil and Gas Wells

Research and Implementation of a New Orientation ＆ Incline ...

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2009 9th International Conference on Electronic Measurement & Instruments（ICEMI’2009）

作者： Chunhua Ren 1 Yingjun Pan 1 Tong He 2 Ninxiang Xiong 1 (1.Key Lab.Of Opto-Electronic Technology & System Ministry Of Education ChongQing University 400044 China) (2.ChongQing New Centrury Areospace Inc. 400037 China)

A new type of oil and gas wells’ orientation ＆ incline system which is constituted of fiber optic gyroscope and MEMS accelerometer has been introduced. And the system scheme methods of dynamic north-seeking and algorithm have been given. By the introduction of low-speed continuous rotation, the adoption of dynamic rotation mode and the using of inertial system’s own output signal , the low- frequency random drift error of fiber-optic gyro is decreased, and ultimately this instrument can achieve the oil and gas wells’ geographic north ＆ Incline angle of probe quickly and accurately. The experimental results show that: the system’s orientation precise is within r1 q, and the level precise is within ***, the system has the advantage of having solid structure,stand high temperature, high shock above 100g , more than 3000h of MTBF, more than 10 years of life expectancy. It is suitable for all-weather field environment, and is the ideal next-generation oil and gas wells’ orientation ＆ Incline measurement instrument.

关键词： oil and gas wells orientation & Incline dynamic north-seeking solid structure

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