Search

In this paper, in order to reduce the indentation rolling resistance of a belt conveyor and improve its operation efficiency, the indentation rolling resistance of a belt conveyor is studied. Firstly, the theoretical calculation of the indentation rolling resistance caused by the contact between a conveyor belt and an idler is studied. Additionally, the expression of the indentation rolling resistance including the multi-element Maxwell relaxation modulus is simplified and deduced using the assumption of small deformation, and the steps of iterative calculation of the indentation rolling resistance through setting the initial values are designed. Then, the multi-component Maxwell relaxation modulus function of the conveyor belt tested in the previous work of the authors is substituted into COMSOL 5.6 finite element software, and the stress distribution caused by the contact between the conveyor belt and the idler under different working conditions is analyzed. Also, a series of measures to reduce the indentation rolling resistance are found through the laws presented by the simulation results. Finally, the experimental study of the indentation rolling resistance is carried out using the indentation rolling resistance testing device from our research group. By comparing the experimental results for the indentation rolling resistance under different working conditions with the theoretical calculation results for the indentation rolling resistance, it was found that the relative error was less than 13%, which proved the feasibility of the indentation rolling resistance and relaxation modulus testing method, as well as the theoretical calculation method for indentation rolling resistance. [ABSTRACT FROM AUTHOR]

Viscoelastic materials are applied in several fields, and their relaxation characteristics are intricately related to the failure mechanism of sealing components and the generation of indentation rolling resistance in belt conveyors. Therefore, it is imperative to explore the relaxation characteristics of viscoelastic materials using characterization models. This article focuses on exploring these characterization models and the indentation rolling resistance of viscoelastic materials. The research comprises the following aspects: (1) A 2N + 2 element generalized Maxwell constitutive model is proposed for the relaxation behavior of viscoelastic materials to address the limitations of conventional relaxation models. (2) We conducted numerical calculations based on the relaxation modulus to solve the relaxation spectrum using several relaxation spectrum models. The findings showed that the model parameters were dependent on the testing time range. (3) The relationship between the indentation rolling resistance and relaxation model parameters was evaluated based on the theoretical foundation of the indentation rolling resistance calculation. [ABSTRACT FROM AUTHOR]

Due to high cost and difficulty to research remote control system for shearer on actual working face, the paper proposed a design scheme of networked remote control testing system for shearer, researched internal control structure of shearer met testing requirements, and introduced design of on-board controller and wireless transceiver controller of shearer, control softwares for ground host and underground host. The system adopts a remote/local control mode to build a network of the remote control system for shearer, and transmits control signal by Ethernet, fiber, RS485 bus and wireless network, realizes remote/local control of shearer action on ground host and underground host. In addition, the testing system also provides an experimental platform for further research of remote control for shearer.

A formula based on Winkler foundation and generalized viscoelastic Maxwell model of belt backing material has been given by Thomas J Rudolphi to determine the indentation rolling resistance. However, this formula must be solved by the iteration. As a result, the influence of some common working conditions can be reflected indirectly on this formula that results in the formula not being useful practically. On the other hand, the formula which is developed by Jonkers can reflect firstly the effect of working condition directly except for belt speed, but this formula has an inherent deficiency where Jonkers assumes that the indentation depth is independent of the belt speed. However, if the vertical load is assumed to be constant then the indentation depth and the contact will decrease with increasing belt speed in nature. Therefore, it offers an advantageous reference for simplifying the Rudolphi’s formula to get an analytic formula which can exhibit the influence of working condition on the rolling resistance. In this paper, author analyzes the effect of common working conditions on rolling resistance with the help of Rudolphi’s formula firstly. Then, in the premise of satisfying the suitable precision, author simplifies the Rudolphi’s formula to get an analytic formula. Finally, a verification example based on experiment is given to validate the rationality of analytic formula which may be of interest to belt-conveyor designers. [ABSTRACT FROM AUTHOR]

A novel near-infrared fluorescent probe TM2 based on a rhodamine-bearing framework was disclosed with a large Stokes shift (100 nm). TM2 exhibits highly selective recognition for Cu 2+ in EtOH/H 2 O (1 : 1, v/v) solution with a low detection limit (2.3 μM) and a wide detection range (0-50 μM). Detection of Cu 2+ is undisturbed at physiological pH levels of 5-9. This recognition mechanism is attributed to the formation of a 1 : 1 complex between TM2 and Cu 2+ , validated by Job's plot, 1 H NMR titration, and LC-MS experiments. Moreover, the successful fluorescence imaging of Cu 2+ both in vitro and in vivo was also accomplished.