Inclined chute flow of rod-like particles using the discrete element method

An inclined chute flow of rod-like particles is investigated both experimentally and analytically. The behavior of the particles is solved by the discrete element method (DEM). The rod-like particle model consists of a cylinder, capped at both ends by hemispheres whose radii are the same as the radius of the cylinder. The rod-like particles have three translational degrees of freedom, their rotational motion being described through quaternions, and the interparticle contact is described by a force that accounts for the elastic and dissipative interactions. The contact patterns for the rod-like particles are classified into six types. In the experiment, brass and acrylic resin cylinders of uniform size were used. The validity of the theory was confirmed by comparing the experimental and analytical results. In addition, the effect of the particle material on the flow pattern was examined

Particle damping for vibration suppression of a clamped plate

In this paper, analytical and experimental studies of the vibration suppression of a square plate with a particle damper are discussed. The primary objective of this paper is to construct an analytical model to simulate the transient impact response of a plate with a particle damper. In the experimental approach, an acrylic resin plate with all sides clamped was used. The transient vibration of the plate caused by the impact of a steel ball was measured with a laser displacement sensor. The effects of the mass ratio, particle material and cavity shape on the damping efficiency were investigated. To capture the behavior of the entire system in detail, an analytical model based on coupling between the finite element method and the discrete element method was constructed. Rayleigh damping was used to approximate the damping behavior of the plate without granular materials. Comparison between the experimental and analytical results showed that accurate estimates of the response of a plate can be obtained

Separation behaviour of small foreign objects in dry foods

It is difficult to detect small foreign objects such as hair and soft plastics in dry foods. In our laboratory, an electrostatic separator of small foreign objects in dry foods was developed. The separator consists of a grounded inclined rotating drum, a cylindrical electrode fixed at the centre of the drum, and a suction device. The principle of the separation is based on the difference in the charge per unit mass of the dry food and foreign objects. Although it was found that it is possible to obtain a high purity and a high recovery rate of foods using this separator, the understanding of the separation mechanism is still limited. In this study, we numerically investigated the separation behaviours of foreign objects and dry foods in the inclined rotating drum. The behaviours of the foreign objects and dry foods were calculated, considering the electrostatic force. The electric field strength was calculated by the finite difference method. The effect of the inclination angle of the rotating drum on the trajectory of the particles to be separated was investigated. To examine the validity of the calculation method, the experimental result was compared with the calculated result

Development of Friction-Damping Vibration Control Device for Low-Rise Buildings

Damage to buildings in Japan during large earthquakes is seen mostly in low-rise buildings which tends to resonate with the earthquake ground motion. In this paper, a novel vibration control device that utilizes frictional forces is presented aimed towards appliction in low-rise buildings. Figure 1 shows a diagram of the installed damping device. The proposed ibration control device, as shown in the detailed drawing in Figure 2, has a structure in which contact with the beam occurs through the action of spring force alone, such that when the building is deformed in an earthquake, damping occurs through the action of frictional forces. In order to evaluate the device, vibration experiments were carried out on a miniature model, as shown in Figure 3. The investigation aimed to: 1) ascertain the appropriate rigidity for the parts on which the damping device is to be installed, 2) analyze the suitable spring tensions and frictional forces, and 3) evaluate the damping effects and construct a vibration model. The results confirmed that the vibration control device confers significant damping in the natural period range of low-rise buildings. In addition, in operation of the device, there is no obvious resonance point in the natural period range

Assessment of Lower-limb Vascular Endothelial Function Based on Enclosed Zone Flow-mediated Dilation

This paper proposes a novel non-invasive method for assessing the vascular endothelial function of lower-limb arteries based on the dilation rate of air-cuff plethysmograms measured using the oscillometric approach. The principle of evaluating vascular endothelial function involves flow-mediated dilation. In the study conducted, blood flow in the dorsal pedis artery was first monitored while lower-limb cuff pressure was applied using the proposed system. The results showed blood flow was interrupted when the level of pressure was at least 50 mmHg higher than the subject’s lower-limb systolic arterial pressure and that blood flow velocity increased after cuff release. Next, values of the proposed index, %ezFMDL, for assessing the vascular endothelial function of lower-limb arteries were determined from 327 adult subjects: 87 healthy subjects, 150 subjects at high risk of arteriosclerosis and 90 patients with cardiovascular disease (CAD). The mean values and standard deviations calculated using %ezFMDL were 30.5 ± 12.0% for the healthy subjects, 23.6 ± 12.7% for subjects at high risk of arteriosclerosis and 14.5 ± 15.4% for patients with CAD. The %ezFMDL values for the subjects at high risk of arteriosclerosis and the patients with CAD were significantly lower than those for the healthy subjects (p < 0.01). The proposed method may have potential for clinical application.This work was supported by JSPS KAKENHI Grant Number 16K21076

Inclined chute flow of rod-like particles using the discrete element method

An inclined chute flow of rod-like particles is investigated both experimentally and analytically. The behavior of the particles is solved by the discrete element method (DEM). The rod-like particle model consists of a cylinder, capped at both ends by hemispheres whose radii are the same as the radius of the cylinder. The rod-like particles have three translational degrees of freedom, their rotational motion being described through quaternions, and the interparticle contact is described by a force that accounts for the elastic and dissipative interactions. The contact patterns for the rod-like particles are classified into six types. In the experiment, brass and acrylic resin cylinders of uniform size were used. The validity of the theory was confirmed by comparing the experimental and analytical results. In addition, the effect of the particle material on the flow pattern was examined