Honggui Di, Shihao Huang, Longlong Fu and Binglong Wang
The paper aims to predict longitudinal deformation of a tunnel caused by grouting under the tunnel bottom in advance according to the grouting parameters, which can ensure the…
Abstract
Purpose
The paper aims to predict longitudinal deformation of a tunnel caused by grouting under the tunnel bottom in advance according to the grouting parameters, which can ensure the safety of the tunnel structure during the grouting process and also help to design the grouting parameters.
Design/methodology/approach
The paper adopted the analytical approach for calculating the longitudinal deformation of a shield tunnel caused by grouting under a tunnel, including usage of the Mindlin’s solution, the minimum potential energy principle and case validation.
Findings
The paper provides a variational method for calculating the longitudinal deformation of a shield tunnel in soft soil caused by grouting under the tunnel, which has high computational efficiency and accuracy.
Originality/value
This paper fulfils an identified need to study how the longitudinal deformation of a shield tunnel in soft soil caused by grouting under the tunnel can be calculated.
Details
Keywords
Shan Peng, Ranran Yang, Binglong Lei, Yun Gao, Renhua Chen, Xiaohong Xia and Kevin P. Homewood
This paper aims to systematically demonstrate a methodology to determine the relative and absolute encapsulation efficiencies (αRe and αAb) for thermally- and chemically-robust…
Abstract
Purpose
This paper aims to systematically demonstrate a methodology to determine the relative and absolute encapsulation efficiencies (αRe and αAb) for thermally- and chemically-robust inorganic pigments, typically like ZrSiO4-based pigments, thereby enhancing their coloring performance.
Design/methodology/approach
The authors designed a route, surplus alkali-decomposition and subsequently strong-acid dissolution (SAD2) to completely decompose three classic zircon pigments (Pr–ZrSiO4, Fe2O3@ZrSiO4 and CdS@ZrSiO4) into clear solutions and preferably used inductively coupled plasma-optical emission spectrometry (ICP-OES) to determine the concentrations of host elements and chromophores, thereby deriving the numeric data and interrelation of αRe and αAb.
Findings
Zircon pigments can be thoroughly decomposed into some dissoluble zirconate–silicate resultants by SAD2 at a ratio of the fluxing agent to pigment over 6. ICP-OES is proved more suitable than some other quantification techniques in deriving the compositional concentrations, thereby the values of αRe and αAb, and their transformation coefficient KRA, which maintains stably within 0.8–0.9 in Fe2O3@ZrSiO4 and CdS@ZrSiO4 and is slightly reduced to 0.67–0.85 in Pr–ZrSiO4.
Practical implications
The SAD2 method and encapsulation efficiencies are well applicable for both zircon pigments and the other pigmental or non-pigmental inhomogeneous systems in characterizing their accurate composition.
Originality/value
The authors herein first proposed strict definitions for the relative and absolute encapsulation efficiencies for inorganic pigments, developed a relatively stringent methodology to determine their accurate values and interrelation.
Details
Keywords
Nailong Liu, Xiaodong Zhou, Zhaoming Liu, Hongwei Wang and Long Cui
This paper aims to enable the robot to obtain human-like compliant manipulation skills for the peg-in-hole (PiH) assembly task by learning from demonstration.
Abstract
Purpose
This paper aims to enable the robot to obtain human-like compliant manipulation skills for the peg-in-hole (PiH) assembly task by learning from demonstration.
Design/methodology/approach
A modified dynamic movement primitives (DMPs) model with a novel hybrid force/position feedback in Cartesian space for the robotic PiH problem is proposed by learning from demonstration. To ensure a compliant interaction during the PiH insertion process, a Cartesian impedance control approach is used to track the trajectory generated by the modified DMPs.
Findings
The modified DMPs allow the robot to imitate the trajectory of demonstration efficiently and to generate a smoother trajectory. By taking advantage of force feedback, the robot shows compliant behavior and could adjust its pose actively to avoid a jam. This feedback mechanism significantly improves the dynamic performance of the interactive process. Both the simulation and the PiH experimental results show the feasibility and effectiveness of the proposed model.
Originality/value
The trajectory and the compliant manipulation skill of the human operator can be learned simultaneously by the new model. This method adopted a modified DMPs model in Cartesian space to generate a trajectory with a lower speed at the beginning of the motion, which can reduce the magnitude of the contact force.