Shanxi Conservancy Technical College

Yuncheng, China

Shanxi Conservancy Technical College

Yuncheng, China
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Zhang X.-L.,Taiyuan University of Technology | Sun X.-H.,Taiyuan University of Technology | Sun X.-H.,Shanxi Conservancy Technical College | Li Y.-Y.,Taiyuan University of Technology
Journal of Hydrodynamics | Year: 2015

Concentric annulus flow around a combinational cylindrical body with a special array of cylinders at five high Reynolds numbers is investigated numerically using Fluent 6.3.26 in this paper. The numerical results show a good agreement with the experimental data in regard to the axial velocity of the flow. This study focuses on the flow structure and the hydrodynamic characteristics based on the velocity distribution, the pressure distribution, streamlines and vectors under 1-D, 2-D and 3-D conditions. Meanwhile, some global parameters including the pressure coefficient, the drag coefficient and the lift coefficient are analyzed. Numerical results show that the high velocity region and the reverse wake zone with low velocity exist in some spaces due to the disturbance of the cylindrical body. Negative pressures appear in some regions. Neither a wide area vortex nor the vortex shedding appears in the wall-bounded domain. The drag along the axial direction is the main force acting on the cylindrical body in the pipe domain. The annulus flow around the cylindrical body is analyzed to reveal the hydrodynamic characteristics of the complex turbule- nt concentric annulus flow field due to the multi-effects in the pipeline. © 2015 Publishing House for Journal of Hydrodynamics.


Yang R.,Shijiazhuang Mechanical Engineering College | Kang J.,Shijiazhuang Mechanical Engineering College | Quan Z.,Shanxi Conservancy Technical College
Science and Technology of Nuclear Installations | Year: 2015

Nuclear power plants are highly complex systems and the issues related to their safety are of primary importance. Probabilistic safety assessment is regarded as the most widespread methodology for studying the safety of nuclear power plants. As maintenance is one of the most important factors for affecting the reliability and safety, an enhanced preventive maintenance optimization model based on a three-stage failure process is proposed. Preventive maintenance is still a dominant maintenance policy due to its easy implementation. In order to correspond to the three-color scheme commonly used in practice, the lifetime of system before failure is divided into three stages, namely, normal, minor defective, and severe defective stages. When the minor defective stage is identified, two measures are considered for comparison: one is that halving the inspection interval only when the minor defective stage is identified at the first time; the other one is that if only identifying the minor defective stage, the subsequent inspection interval is halved. Maintenance is implemented immediately once the severe defective stage is identified. Minimizing the expected cost per unit time is our objective function to optimize the inspection interval. Finally, a numerical example is presented to illustrate the effectiveness of the proposed models. © 2015 Ruifeng Yang et al.


Zhang Y.-C.,Key Laboratory of Highway Construction and Maintenance Technology in Loess Region | Zhang Y.-C.,Chinese Research Institute of Highway | Gao L.-L.,Shanxi Conservancy Technical College
Green Building, Materials and Civil Engineering - Proceedings of the 4th International Conference on GreenBuilding, Materials and Civil Engineering, GBMCE 2014 | Year: 2015

The reason of sulfate attack of concrete was analyzed from Aft damage, CaS04·2H2O damage, Mg2+ damage and thaumasite damage. Then the effect of performance of concrete itself, corrosion solution, the environment and working conditions on sulfate corrosion of concrete was determined. © 2015 Taylor & Francis Group, London.


Zhang Y.-C.,Chinese Research Institute of Highway | Gao L.-L.,Shanxi Conservancy Technical College
Applied Mechanics and Materials | Year: 2013

A number of rubber cement dosage specimens that rubber powder dosage different were obtained using same cement, water and fine aggregates, by adjusting the dosage of rubber powder. Then it was used to research the influence of rubber powder dosage on performance of cement mortar by measuring its liquidity, strength and toughness. The results show that: when water-cement ratio was equal and rubber powder replacing the same volume sand, the fluidity of cement mortar almost linear increased with rubber powder dosage increasing. With dosage of rubber powder increasing, compressive strength and flexural strength reduced, but toughness linear growth trend when dosage of rubber powder less 30%. © (2013) Trans Tech Publications, Switzerland.


Zhang Y.-C.,Chinese Research Institute of Highway | Liu S.-W.,Chinese Research Institute of Highway | Gao L.-L.,Shanxi Conservancy Technical College
Advanced Materials Research | Year: 2014

A number of rubber cement concrete specimens that rubber powder dosage different were obtained using same cement, water and fine aggregates, by adjusting the dosage of rubber powder. Then it was used to research the influence of rubber powder dosage on performance of cement concrete by measuring its liquidity, strength and toughness. The results show that: when water-cement ratio was equal and rubber powder replacing the same volume sand, the fluidity of cement concrete almost linear increased with rubber powder dosage increasing. With dosage of rubber powder increasing, compressive strength and flexural strength reduced, but toughness linear growth trend when dosage of rubber powder less 30%. © (2014) Trans Tech Publications, Switzerland.


Zhang Y.-C.,Chinese Research Institute of Highway | Gao L.L.,Shanxi Conservancy Technical College
Advanced Materials Research | Year: 2013

High frequency vibration was brought to two different air-entrained concrete. Pore structure analyzer of hardened concrete quantitatively described the influence of vibration to air content, air spacing coefficient and bubble size distribution. Meanwhile, the relationship between high frequency vibration and the ability of frost resistance was accurately determined through the testing freeze-thaw cycle. The results showed that: long time high frequency vibration would cause decline of frost resistance. © (2013) Trans Tech Publications, Switzerland.


Zhang Y.-C.,Chinese Research Institute of Highway | Zhang Y.-C.,Changsha University of Science and Technology | Gao L.-L.,Shanxi Conservancy Technical College
International Journal of Pavement Research and Technology | Year: 2016

A double-layer structure model of pavements that considered interlayer contact status was established to manage the dowel-bar position deviation problem in rigid pavements. The deviation effect of three-dimensional positions, such as horizontal angle, vertical angle, and embedded depth, on joint load-transfer capacity was analyzed. A load-transfer capacity prediction model that considered dowel bar position deviation was established via ternary nonlinear regression. Load correction factor and its range were also proposed. This prediction model can effectively reflect the joint load-transfer capacity during dowel position deviation after verification via falling weight deflectometer testing. The horizontal angle of the dowel bar minimally affected joint load-transfer coefficient. By contrast, the joint load-transfer coefficient decreased almost linearly as the vertical angle increased. The coefficient reduced by approximately 12% when the vertical angle was 15°. Meanwhile, the load-transfer coefficient was maximized when a dowel bar was embedded in the middle of a surface. The coefficient would decline either upward or downward. The coefficient particularly decreased by 10% when the position was 2 cm downward. © 2016 Chinese Society of Pavement Engineering.


Zhang Y.,Chinese Research Institute of Highway | Gao L.,Shanxi Conservancy Technical College
ICTE 2015 - Proceedings of the 5th International Conference on Transportation Engineering | Year: 2015

For the problem what particle size and dosage of crumb rubber powder is best for road concrete, 24 groups of rubber powder concrete were prepared using four kinds of particle size (60,80,100 and 120 meshes) and 6 kinds of dosage (0%, 10%, 15%, 20%, 25% and 30%). And its pavement performance was measured, such as, strength, toughness, crack resistance, frost resistance and permeability. The results showed that: strength of crumb rubber powder concrete decreased with dosage and fineness degree of rubber powder increasing, and it had a higher sensitivity for dosage. Add crumb rubber powder into concrete has a positive effect to improve toughness, crack resistance and permeability of concrete, and the effect can be more obvious when the dosage increasing. However, the ability of frost resistance increased at first, and then decreased when the dosage increasing. The optimum dosage for 60, 80, 100 and 120 meshes rubber powder was 15%. © ASCE.


Zhang Y.-C.,Chinese Research Institute of Highway | Gao L.-L.,Shanxi Conservancy Technical College | Sili L.,Chinese Research Institute of Highway
Advanced Materials Research | Year: 2014

Three-dimensional structure model on Winkler foundation considering inter layer contact status was established. The effect that base modulus, thickness and inter layer contact status between slab and base to maximum stress of slab bottom and base bottom, shear stress between slab and base, warping of slab was calculated. The results showed that: interlayer contact status had great influence on slab stress and warping. Maximum stress of slab bottom dropped while bonding status decreased and slab warping increased obviously while bonding status weakened. Base modulus was the primary factor for base stress. Maximum stress of base bottom increased while modulus increased, and decreased while bonding status weakened. Interlayer shear stress occurred mainly at slab edge, and decreased while the bonding status weakened, almost had no correlation to base modulus and thickness. © (2014) Trans Tech Publications, Switzerland.


Wang R.-J.,China Institute for Radiation Protection | Duan Y.-Y.,Shanxi Conservancy Technical College
Hedianzixue Yu Tance Jishu/Nuclear Electronics and Detection Technology | Year: 2013

Evaluation of uncertainty is the important content of radioactive measurement. The thesis takes soil sample using HPGe gamma instrument as an example, analyzes the cause of uncertainty from the instrument calibration, sample preparation and measurement process. The uncertainty mainly includes calibration source, background of Instrument, activity of sample, measuring time, difference between sample and calibration source. Through calculation increasing measure time can reduce uncertainty.

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