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Li Daolun¹, Lu Detang¹, Liu Cong¹
Structural Longevity, Vol.10, No.2, pp. 71-84, 2013, DOI:10.3970/sl.2013.010.071
Abstract CO2 or acidic material injection into oil reservoirs or Alkaline-surfactantpolymer (ASP) flooding induces reactivity between CO2, acid, ASP, pore-waters and minerals, which results in modification of porosities and permeabilities. We use dilation operation to simulate the modification of the porosities and study the variation of permeabilities. Firstly we get digital images from CT experiment of a real rock core. Secondly the pore space of digital cores is expanded by dilation operation which is one of basic mathematical morphologies. Thirdly, the distribution of pore bodies and pore throats are obtained from the pore network modeling extracted by maximal ball method. Finally,… More >

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Boyun Guo¹, Yin Feng²
Structural Longevity, Vol.10, No.2, pp. 85-94, 2013, DOI:10.3970/sl.2013.010.085
Abstract A new numerical procedure, called Semi-Alternating Direction Implicit (SADI), was developed for solving the Diffusivity Equation (DE) using the Finite Difference Method (FDM) in this study. The SADI procedure was compared with the Simultaneous Sweep (SS) procedure and the Alternating Direction Implicit (ADI) procedure in terms of numerical stability and computing speed in a 3-dimensional oil reservoir simulator. Results from the model-testing indicate that, due to different degrees of numerical dispersion, the function values generated by the SADI procedure are slightly greater than that by the SS procedure and the ADI procedure. The SADI procedure is as stable as the… More >

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Dǎnu¸t Receanu¹
Structural Longevity, Vol.10, No.2, pp. 95-106, 2013, DOI:10.3970/sl.2013.010.095
Abstract The paper presents a conceptually simple nonlinear controller, commonly called computer torque controller, which can fully compensate the nonlinear forces: Coriolis and centripetal forces (natural and continuous nonlinearities) and at the same time the program in Simulink can fully compensate the natural and discontinuous nonlinearities (hard nonlinearities): friction and backlash utilizing the intentional nonlinearities artificially introduced in system and lead to high accuracy control for a very large range of robot speeds and a large workspace. More >

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Salah Amer¹, Wonchang Choi², Miguel Picornell³, Sameer Hamoush³
Structural Longevity, Vol.10, No.2, pp. 107-118, 2013, DOI:10.3970/sl.2013.010.107
Abstract The World War Memorial Stadium located at 510 Yanceyville St. Greensboro, North Carolina was built in 1926 at the. Currently, the stadium is used as a baseball field for NC A&T State University and University of NC at Greensboro. The stadium was designed by the architect, White, Leonard, Jr. and Barton Harry with architectural style modern classicism. The stadium is maintained by The Parks and Recreation Department of the City of Greensboro who invited the Department of Civil Engineering, College of Engineering at NC A&T State University to assess and evaluate the structural conditions of the stadium. The outcome of… More >

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Wang Changhong¹, Xu Yiyan¹, Zhu Hehua²
Structural Longevity, Vol.10, No.2, pp. 119-133, 2013, DOI:10.3970/sl.2013.010.119
Abstract In order to generate 3-dimensional (3D) strata, a stratum data model of tri-prism based on borehole data is first presented, which is applicable in geological engineering and geotechnical engineering. Due to the local variance and spatial structure among attributes of boreholes, the geological properties at unknown location have to be estimated or interpolated by some special methods. However, classic statistical methods could not resolve such problem which includes selection of sample points, spatial estimation and comparison of bilateral data. A distanceweighted interpolation method for scattered borehole data points is proposed in this paper, which exploits the Kriging method in global… More >

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