• Geomechanics and Engineering
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• v.31 no.6
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• pp.599-614
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• 2022

One of the methods of stabilizing retaining walls, embankments, and deep excavations is the implementation of plate anchors (like the Geolock wall anchor systems). Back-to-back Mechanically Stabilized Earth (BBMSE) walls are common stabilized earth structures that can be used for bridge ramps. But so far, the analysis of the interactive behavior of two back-to-back anchored walls (BBAW) by double-plates anchors (constructed closely from each other and subjected to the limited-breadth vertical loading) including interference of their failure and sliding surfaces has not been the subject of comprehensive studies. Indeed, in this compound system, the interaction of sliding wedges of these two back-to-back walls considering the shear failure wedge of the foundation, significantly impresses on the foundation bearing capacity, adjacent walls displacements and deformations, and their stability. In this study, the effect of horizontal distance between two walls (W), breadth of loading plate (B), and position of vertical loading was investigated experimentally. In addition, the comparison of using single and equivalent double-plate anchors was evaluated. The loading plate bearing capacity and displacements, and deformations of BBAW were measured and the results are presented. To evaluate the shape, form, and how the critical failure surfaces of the soil behind the walls and beneath the foundation intersect with one another, the Particle Image Velocimetry (PIV) technique was applied. The experimental tests results showed that in this composite system (two adjacent-loaded BBAW) the effective distance of walls is about W = 2.5*H (H: height of walls) and the foundation effective breadth is about B = H, concerning foundation bearing capacity, walls horizontal displacements and their deformations. For more amounts of W and B, the foundation and walls can be designed and analyzed individually. Besides, in this compound system, the foundation bearing capacity is an exponential function of the System Geometry Variable (SGV) whereas walls displacements are a quadratic function of it. Finally, as an important achievement, doubling the plates of anchors can facilitate using concrete walls, which have limitations in tolerating curvature.

• The Korean Journal of Rheology
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• v.10 no.4
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• pp.195-201
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• 1998

We have studied the rheological and electrical properties of two types of electrorheological (ER) fluids based on semi-conductive polymers (poly(p-phenylene) and polyaniline). These semi-conductive polymer-based suspensions showed a dramatic increase in viscosity on the application of the static electric field due to the large value of conductivity ratio between particle and medium. The dynamic yield stresses of these ER suspensions exhibited a quadratic dependence on electric field strength at low electric fields and a linear one for high fields. They showed a maximum and then decreased with increasing bulk conductivity of particles. These yield stress behaviors under the static electric field were found to be closely related to the dielectric properties, which is in accord with Maxwell-Wagner interfacial polarization induced by the conductivity effects. In order to achieve better understanding of interfacial polarization effect on ER response and to improve the stability of ER suspension, different kinds of surfactants were employed for controlling the ER activity as well as for enhancing the colloidal stability of suspensions.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1883-1886
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• 2005

In this paper, a decoupled dual servo (DDS) stage for ultra-precision scanning system with large working range is introduced. In general, dual servo systems consist of a fine stage for short range and a coarse stage for long range. The proposed DDS also consists of a $XY\theta$ fine stage for handling and carrying workpieces and one axis coarse stage. Its coarse stage consists of air bearing guide system and a coreless linear motor with force ripple. The fine has four voice coil motors(VCM) as its actuator. According to a VCM's nature, there are no mechanical connections between coils and magnetic circuits. Moreover, VCM doesn't have force ripples due to imperfections of commutation components of linear motor systems - currents and flux densities. However, due to the VCM's mechanical constraints the working range of the fine is about $25mm^2$. To break that hurdle, the coarse stage with linear motors is used to move the fine about 500mm. Because of the above reasons, the proposed DDS can achieve higher precision scanning than other stages with only one servo. With MATLAB's Sequential Quadratic Programming (SQP), the VCMs are optimally designed for the highest force under conditions and constraints such as thermal dissipations due to its coil, its size, and so on. And for their movements without any frictions, guide systems of the DDS are composed of air bearings. To get precisely their positions, a linear scale with 5nm resolution are used for the coarse stage's motion and three plane mirror laser interferometers with 5nm for the fine's $XY\theta$ motions. With them, on scanning the two stages have same trajectories. The control algorithm is named Parallel method. The embodied ultra-precision scanning system has sub 100nm following error and in-positioning stability.

• Animal Bioscience
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• v.37 no.6
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• pp.1053-1064
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• 2024

Objective: This study aims to investigate the interactive effect of a glycine equivalent (Gly_equi) and standardized ileal digestible threonine (SID Thr) levels in low crude protein diets on performance, blood biochemistry, pectoral muscular creatine content and oxidative stability of meat in broiler chickens from 21 to 42 days. Methods: A total of 1,500, twenty-one-day-old Cobb-Vantress male broiler chickens were distributed in a completely randomized 5×3 factorial arrangement of Gly_equi×SID Thr with five replicates of 20 birds each. Fifteen dietary treatments of 16.5% CP were formulated to contain five levels of total Gly_equi (1.16%, 1.26%, 1.36%, 1.46%, and 1.56%) and three levels of SID Thr (0.58%; 0.68% and 0.78%). Results: Interaction effects (p<0.05) of Gly_equi and SID Thr levels were observed for weight gain, carcass yield, pectoral muscular creatine content and serum uric acid. Higher levels of Gly_equi increased (p = 0.040) weight gain in 0.58% and 0.68% SID Thr diets compare to the 0.78% SID Thr diet. The SID Thr level at 0.68% improved (p = 0.040) feed conversion compared to other SID Thr diets. Levels of Gly_equi equal to or above 1.26% in diets with 0.78% SID Thr resulted in birds with higher (p = 0.033) pectoral muscular creatine content. The breast meat yield observed in the 0.68% SID Thr diet was higher (p = 0.05) compared to the 0.58% SID Thr diet. There was a quadratic effect of Gly_equi levels for pectoral pectoral muscular creatine content (p = 0.008), breast meat yield (p = 0.030), and serum total protein concentrations (p = 0.040), and the optimal levels were estimated to be 1.47%, 1.35%, and 1.40% Gly_equi, respectively. The lowest (p = 0.050) concentration of malondialdehyde in the breast meat was found in 0.68% SID Thr diets at 1.36% Gly_equi. Conclusion: The minimum dietary level of Gly_equi needed to improve performance in low crude protein diets is 1.26% with adequate SID Thr levels for broiler chickens.