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In this study, a novel magnetorheological (MR) polishing device under a compound magnetic field is designed to achieve microlevel polishing of the titanium tubes. The polishing process is realized by combining the rotation motion of the tube and the reciprocating linear motion of the polishing head. Two types of excitation equipment for generating an appropriate compound magnetic field are outlined. A series of experiments are conducted to systematically investigate the effect of compound magnetic field strength, rotation speed, and type and concentration of abrasive particles on the polishing performance delivered by the designed device. The experiments were carried out through controlling variables. Before and after the experiment, the surface roughness in the polished area of the workpiece is measured, and the influence of the independent variable on the polishing effect is judged by a changing rule of surface roughness so as to obtain a better parameter about compound magnetic field strength, concentration of abrasive particles, etc. It is shown from experimental results that diamond abrasive particles are appropriate for fine finishing the internal surface of the titanium-alloy tube. It is also identified that the polishing performance is excellent at high magnetic field strength, fast rotation speed, and high abrasive-particle concentration.

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This study investigates friction and wear properties of rod seals used to prevent leakage of base oil in magnetorheological (MR) dampers. As the first step, a non-piston MR damper (MRD) model is considered for the analysis of both the frictional force and three-body abrasive wear of seals in MRD. Three different seals; O-ring, step ring, and glyd ring seals are adopted for the analysis and experimental tests. In order to conduct the friction and wear testing, a new type of in-house experimental apparatus consisting of an electrical cylinder, pressure sensor and gravity sensor is established. Subsequently, the friction coefficients and wear losses of the seals are evaluated as a function of operation time to validate the feasibility of the derived friction and wear models. To investigate the variation of the seals within MR fluid domain, morphological scanning electron microscopy images such as contacting and worn surfaces are observed and discussed. In addition, the energy-dispersive spectroscopy images are investigated after wearing the seal to observe the changes in size and shape of iron particles which are randomly distributed in MR fluid.

Processing tomato (Lycopersicon esculentum Mill.) is a very important horticultural product all over the world. Soluble solid content (SSC) as a key quality assessment parameter of processing tomato directly affects quality and cost of processing tomato products such as tomato paste. This study proposes an analytical method for quantitatively assessment of SSC in processing tomatoes by using the visible and near-infrared (Vis-NIR) hyperspectral transmittance imaging technique and multiparameter compensation models. Monte-Carlo outlier detection method was applied to optimize sample set. The competitive adaptive reweighted sampling (CARS) algorithm was used to identify the optimal wavelengths from transmittance spectra. Two characteristic parameters including area (size) and weight of samples were measured and different models including conventional PLS/LS-SVM models and multiparameter compensation PLS/LS-SVM models were established, respectively. The results obtained by comparing all the established models showed that the multiparameter (spectrum, area, and weight) compensation CARS-LS-SVM model with 47 important wavelengths had the best assessment ability of SSC in processing tomatoes. The prediction accuracies of the optimal model are r cal = 0.95 and RMSEC = 0.16 for calibration set, and r pre = 0.94, RMSEP = 0.17 and RPD = 2.94 for prediction set, respectively. Research results indicated that the newly proposed Vis-NIR hyperspectral transmittance imaging combining with multi-parameter compensation LS-SVM model would be potential as a noninvasive technique to quantitatively evaluate the SSC in processing tomatoes. the acquisition capability of effective spectral information from the tested object.This work was valuable for setting up the fast multispectral inspection system that can be used for SSC measurement of processing tomatoes in practical on-line grading applications.