This paper presents a novel magnetorheological (MR) damper with a self-powered capability, which is proposed to have energy harvesting and MR damping technologies integrated into a single device. Vibration energy harvesting mechanisms were adopted, based on ball-screw mechanisms and a rotary permanent magnet dc generator, to convert the external vibration energy into electrical energy to power the MR damping unit. The configuration and operating principles of the proposed self-powered MR damper were presented. Considering the core loss effect on the magnetic field, a theoretical analysis of the proposed MR damper was carried out and a mechanical model was developed. Finally, a prototype with a capacity of 10 kN was fabricated and experimentally investigated in both the direct-supply mode and the supply-withrectifier mode. The results indicated that the proposed configuration is feasible and that both modes can realize good self-adaptability of the MR damping force. However, the direct-supply mode has a sag effect in the force-displacement curve and provides a lower energy-dissipating capacity than the direct-supply mode does under the same conditions.

In this paper, we manufactured a novel sandwich panel that comprised of the foam core and the hybrid facesheets by vacuum-assisted resin infusion process. In the hybrid facesheets, the reinforcing phases are made of woven glass fabric cloth in company with wire nets, while the matrix is epoxy resin. Four categories of specimens with different wire nets contents are designed. To investigate the impact resistance ability of the designed sandwich panel, low-velocity impact tests are performed with respect to the contact load, absorbed energy, and failure mode. Compression-after-impact test is conducted to determine the residual mechanical properties of the postimpact sandwich panels. Digital image correlation technology is adopted to measure the strain distribution in the panels in compression-after-impact test. Results show that wire nets in the facesheet of the sandwich panel could enhance the energy absorb ability as well as the compression-after-impact strength significantly. Fiber/wire nets breaking, delamination, and foam core cracking are the main damage modes formed in the impact event, while the incident energy is mainly absorbed by wire nets breaking. In compression-after-impact test, bucking and delamination are the main damage modes, and the compressive stability is enhanced by the wire nets.

Membrane-type acoustic metamaterials (MAMs) are lightweight and flimsy materials with excellent low-frequency insulation performance, which breaks the limitations of the traditional mass law and provides a new idea for noise reduction in the low-frequency range. To further broaden the sound insulation bandwidth on the premise of lightweight design, a novel MAM with petal-like rings is proposed, and the parametric studies on the structural parameters of split rings are carried out in this paper. By combining the finite element model simulation and impedance tube test, the effectiveness of the proposed structure and the correctness of the numerical simulation are validated. Moreover, the sound transmission loss curves and modal shapes of four different structures are computed and analyzed to clarify the insulation mechanism of the novel structure. Finally, the width, the center angle, the centroid position, and the weight of the split rings in the novel structure are parametrically analyzed to figure out the regulation rules of the sound insulation characteristics.

Objective: Atherosclerosis is an arterial occlusive disease with hypercholesterolemia and hypertension as common risk factors. Advanced-stage stenotic plaque, which features inflammation and necrotic core formation, is the major reason for clinical intervention. Receptor interacting serine/threonine-protein kinase 1 (RIPK1) mediates inflammation and cell death and is expressed in atherosclerotic lesions. The role of RIPK1 in advanced-stage atherosclerosis is unknown.Approach and Results: To investigate the effect of RIPK1 inhibition in advanced atherosclerotic plaque formation, we used ApoESA/SA mice, which exhibit hypercholesterolemia, and develop angiotensin-II mediated hypertension upon administration of doxycycline in drinking water. These mice readily develop severe atherosclerosis, including that in coronary arteries. Eight-week-old ApoESA/SA mice were randomized to orally receive a highly selective RIPK1 inhibitor (RIPK1i, GSK547) mixed with a western diet, or control diet. RIPK1i administration reduced atherosclerotic plaque lesion area at 2 weeks of treatment, consistent with suppressed inflammation (MCP-1, IL-1β, TNF-α) and reduced monocyte infiltration. However, administration of RIPK1i unexpectedly exacerbated atherosclerosis at 4 weeks of treatment, concomitant with increased macrophages and lipid deposition in the plaques. Incubation of isolated macrophages with oxidized LDL resulted in foam cell formation in vitro. RIPK1i treatment promoted such foam cell formation while suppressing the death of these cells. Accordingly, RIPK1i upregulated the expression of lipid metabolism-related genes (Cd36, Ppara, Lxrα, Lxrb, Srebp1c) in macrophage foam cells with ABCA1/ABCG1 unaltered. Furthermore, RIPK1i treatment inhibited ApoA1 synthesis in the liver and reduced plasma HDL levels.Conclusion: RIPK1 modulates the development of atherosclerosis in a stage-dependent manner, implicating both pro-atherosclerotic (monocyte infiltration and inflammation) and anti-atherosclerotic effects (suppressing foam cell accumulation and promoting ApoA1 synthesis). It is critical to identify an optimal therapeutic duration for potential clinical use of RIPK1 inhibitor in atherosclerosis or other related disease indications.

This article presents the development of a novel magnetorheological damper with velocity self-sensing capability. The velocity self-sensing mechanism, based on the optical tracking technology and numerical circuit technology, was adopted. The configuration and work principle of the velocity self-sensing magnetorheological damper were presented. The self-sensing circuits, built with optical mouse sensor and microcontrollers, were integrated into the hollow upper lid. The hollow upper lid provides a suitable place for the self-sensing circuits, can be installed and disassembled easily, and can be maintained efficiently. The velocity self-sensing magnetorheological damper prototype with 10 kN capacity was theoretically analyzed, fabricated, and investigated. Finally, the damping performance, self-sensing performance, and self-sensing control capability were tested and analyzed. The results indicated that self-sensing velocity unit has high accurate monitoring capability over a wide range of working conditions. The velocity self-sensing magnetorheological damper–based control system has sufficient ability to control the magnetorheological damper.