Recent Advances in Multifunctional Wearable Sensors and Systems: Design, Fabrication, and Applications.

Multifunctional wearable sensors and systems are of growing interest over the past decades because of real-time health monitoring and disease diagnosis capability. Owing to the tremendous efforts of scientists, wearable sensors and systems with attractive advantages such as flexibility, comfort, and long-term stability have been developed, which are widely used in temperature monitoring, pulse wave detection, gait pattern analysis, etc. Due to the complexity of human physiological signals, it is necessary to measure multiple physiological information simultaneously to evaluate human health comprehensively.

A two-stage dimension-reduced dynamic reliability evaluation (TD-DRE) method for vibration control structures based on interval collocation and narrow bounds theories.

Due to the uncertainties from modeling, manufacturing, and working environments, many vibration active control systems usually show dynamic uncertain properties. Hence structural reliability estimation benchmarking to full-cycle vibratory responses is vitally important. In this study, a novel two-stage dimension-reduced dynamic reliability evaluation (TD-DRE) method for linear quadratic regulator (LQR) controlled structures is developed.

sEMG-Based Gain-Tuned Compliance Control for the Lower Limb Rehabilitation Robot during Passive Training.

The lower limb rehabilitation robot is a typical man-machine coupling system. Aiming at the problems of insufficient physiological information and unsatisfactory safety performance in the compliance control strategy for the lower limb rehabilitation robot during passive training, this study developed a surface electromyography-based gain-tuned compliance control (EGCC) strategy for the lower limb rehabilitation robot. First, the mapping function relationship between the normalized surface electromyography (sEMG) signal and the gain parameter was established and an overall EGCC strategy proposed.

Human-Robot Cooperative Strength Training Based on Robust Admittance Control Strategy.

A stroke is a common disease that can easily lead to lower limb motor dysfunction in the elderly. Stroke survivors can effectively train muscle strength through leg flexion and extension training. However, available lower limb rehabilitation robots ignore the knee soft tissue protection of the elderly in training.

Tribological Aspects Concerning the Study of Overhead Crane Brakes.

The aim of the study is the tribological analysis of the crane drum brakes. A theoretical analysis of the wear processes for brake lining was performed and the coefficient of friction under tribological conditions was determined experimentally simulating the operating conditions for three types of brakes. The theoretical study of the wear was oriented towards of determining the lifetime of the brake lining.

A finite element analysis on the biomechanical performance of implant-retained finger prostheses designed for Asians.

This study aims to explore the biomechanical performance of implant-retained finger prostheses of different lengths and diameters designed specifically for Asians under external loads from different directions by the finite element method. According to the metacarpophalangeal stumps (length: 4, 7, 10 mm, diameter: 3.5, 4.

Mathematical Model for Skin Pain Sensation under Local Distributed Mechanical Compression for Electronic Skin Applications.

Skin pain resulting from mechanical compression is one of the most common pains in daily life and the indispensable information for electronic skin to perceive external signals. The external mechanical stimuli are transduced into impulses and transmitted via nerve fiber, and finally, the sensation is perceived via the procession of the nerve system. However, the mathematical mechanism for pain sensation due to mechanical stimuli remains unclear.

Multifield Modeling and Simulation of Nutrient Transport in Mechanically Stressed Meniscus Tissue.

Insights into the transport mechanisms of nutrients are essential for understanding the pathophysiology of menisci. In the present work, we focus on the modeling and numerical simulation of the transport of glucose molecules in mechanically stressed meniscus tissue. Therefore, a multifield model based on the theory of porous media is created.

Transient Heat Conduction in the Orthotropic Model with Rectangular Heat Source.

Epidermal electronic systems (EESs) are a representative achievement for utilizing the full advantages of ultra-thin, stretchable and conformal attachment of flexible electronics, and are extremely suitable for integration with human physiological systems, especially in medical hyperthermia. The stretchable heater with stable electrical characteristics and a uniform temperature field is an irreplaceable core component. The inorganic stretchable heater has the advantage of maintaining stable electrical characteristics under tensile deformation.

A Wearable Flexible Acceleration Sensor for Monitoring Human Motion.

Skin-inspired flexible wearable acceleration sensors attract much attention due to their advantages of portability, personalized and comfortable experience, and potential application in healthcare monitoring, human-machine interfaces, artificial intelligence, and physical sports performance evaluation. This paper presents a flexible wearable acceleration sensor for monitoring human motion by introducing the island-bridge configuration and serpentine interconnects. Compared with traditional wearable accelerometers, the flexible accelerometer proposed in this paper improves the wearing comfort while reducing the cost of the device.

An Analytic Orthotropic Heat Conduction Model for the Stretchable Network Heaters.

Compared with other physiotherapy devices, epidermal electronic systems (EES) used in medical applications such as hyperthermia have obvious advantages of conformal attachment, lightness and high efficiency. The stretchable flexible electrode is an indispensable component. The structurally designed flexible inorganic stretchable electrode has the advantage of stable electrical properties under tensile deformation and has received enough attention.

Moisture-resistant, stretchable NO gas sensors based on laser-induced graphene for environmental monitoring and breath analysis.

The accurate, continuous analysis of healthcare-relevant gases such as nitrogen oxides (NO) in a humid environment remains elusive for low-cost, stretchable gas sensing devices. This study presents the design and demonstration of a moisture-resistant, stretchable NO gas sensor based on laser-induced graphene (LIG). Sandwiched between a soft elastomeric substrate and a moisture-resistant semipermeable encapsulant, the LIG sensing and electrode layer is first optimized by tuning laser processing parameters such as power, image density, and defocus distance.

Does a Moderately Warming Climate Compensate for the Negative Effects of UV-B Radiation on Amphibians at High Altitudes? A Test of Living on the Qinghai-Tibetan Plateau.

Both the warming climate and ultraviolet-B radiation (UVBR) are considered to be notable environmental factors affecting amphibian population decline, with particular effects on tadpole development. However, the phenotypes of tadpoles living at high altitudes may be improved by moderately warming temperatures, reducing or eliminating the negative effects of oxidative damage caused by cool temperatures or strong UVBR at high altitudes. To verify this hypothesis, tadpoles, which live at high altitudes, were used to test the effect of the interaction of temperature and UVBR on their development and antioxidant systems in a fully factorial design.

Multi-functional topology optimization of veins.

The growth and development of biological tissues and organs strongly depend on the requirements of their multiple functions. Plant veins yield efficient nutrient transport and withstand various external loads. , a tropical species of the Nymphaeaceae family of water lilies, has evolved a network of three-dimensional and rugged veins, which yields a superior load-bearing capacity.

Modeling and simulation of diffusion and reaction processes during the staining of tissue sections on slides.

Histological slides are an important tool in the diagnosis of tumors as well as of other diseases that affect cell shapes and distributions. Until now, the research concerning an optimal staining time has been mainly done empirically. In experimental investigations, it is often not possible to stain an already-stained slide with another stain to receive further information.

The Hybrid Position/Force Walking Robot Control Using Extenics Theory and Neutrosophic Logic Decision.

This paper presents a hybrid force/position control. We developed it for a hexapod walking robot that combines multiple bipedal robots to increase its load. The control method integrated Extenics theory with neutrosophic logic to obtain a two-stage decision-making algorithm.

Panoramic/Dual-Surface Digital Image Correlation Measurement Using a Single Camera.

We propose a cost-effective and simple-to-implement mirror-assisted single-camera panoramic digital image correlation (DIC) method for panoramic/dual-surface profile and deformation measurement. Specifically, two planar mirrors and a single camera attached with a four-mirror adapter are used to capture stereo images of the front and rear surfaces of a test object. These stereo images can be processed by regular stereo-DIC to retrieve shape and kinematics fields of each surface.

Biomechanical analysis of all-polyethylene total knee arthroplasty on periprosthetic tibia using the finite element method.

Background And Objective: Total knee arthroplasty (TKA) with modern all-polyethylene tibial (APT) components has shown high long-term survival rates and comparable results to those with metal-backed tibial components. Nevertheless, APT components are primarily recommended for older and low-demand patients. There are no evidence-based biomechanical guidelines for orthopaedic surgeons to determine the appropriate lower age limit for implantation of APT components.

Ultra-high temperature video extensometer: System development and experimental validation.

The video extensometer has been widely advocated for tensile/compressive strain measurement in high-temperature material testing due to its advantages of non-contact measurement, wider measuring range, and larger applicable temperature over traditional clip-on mechanical extensometers. However, existing video extensometers, despite the adoption of active imaging devices, cannot adapt to the rapidly changing thermal radiation from the heated sample and surrounding heating elements during the high-temperature tests. This is because due to the significantly intensified thermal radiation, the decorrelated images degrade the measuring accuracy or even destroy the analysis.

Thermal Management of Serpentine Flexible Heater Based on the Orthotropic Heat Conduction Model.

Flexible heaters can perfectly fit with undevelopable surfaces for heating in many practical applications such as thermotherapy, defogging/deicing systems and warming garments. Considering the requirement for stretchability in a flexible heater, certain spacing needs to be retained between serpentine heat sources for deformation which will inevitably bring critical challenges to the thermal uniformity. In order to reconcile these two conflicting aspects, a novel method is proposed by embedding the serpentine heat source in orthotropic layers to achieve comprehensive performance in stretchability and uniform heating.

Poisson's ratio and compressibility of arterial wall - Improved experimental data reject auxetic behaviour.

Poisson's ratio of fibrous soft tissue is analyzed in this paper on the basis of direct experimental measurements of porcine arterial wall layer under uniaxial tension and immersed in tempered saline bath. The current study follows the previously published testing methodology but with a new totally redesigned testing apparatus allowing more credible and precise evaluation of arterial wall behaviour. The new results confirm most of previous findings focused on positivity/negativity of Poisson's ratio playing a crucial role in (in)validation aspects of some constitutive models widely used in recent computational vascular mechanics.

Intrinsically Breathable and Flexible NO Gas Sensors Produced by Laser Direct Writing of Self-Assembled Block Copolymers.

The surge in air pollution and respiratory diseases across the globe has spurred significant interest in the development of flexible gas sensors prepared by low-cost and scalable fabrication methods. However, the limited breathability in the commonly used substrate materials reduces the exchange of air and moisture to result in irritation and a low level of comfort. This study presents the design and demonstration of a breathable, flexible, and highly sensitive NO gas sensor based on the silver (Ag)-decorated laser-induced graphene (LIG) foam.

Island Effect in Stretchable Inorganic Electronics.

Island-bridge architectures represent a widely used structural design in stretchable inorganic electronics, where deformable interconnects that form the bridge provide system stretchability, and functional components that reside on the islands undergo negligible deformations. These device systems usually experience a common strain concentration phenomenon, i.e.

Improvement of Schottky Contacts of Gallium Oxide (GaO) Nanowires for UV Applications.

Interest in the synthesis and fabrication of gallium oxide (GaO) nanostructures as wide bandgap semiconductor-based ultraviolet (UV) photodetectors has recently increased due to their importance in cases of deep-UV photodetectors operating in high power/temperature conditions. Due to their unique properties, i.e.

Triboelectric Response of Electrospun Stratified PVDF and PA Structures.

Utilizing the triboelectric effect of the fibrous structure, a very low cost and straightforward sensor or an energy harvester can be obtained. A device of this kind can be flexible and, moreover, it can exhibit a better output performance than a device based on the piezoelectric effect. This study is concerned with comparing the properties of triboelectric devices prepared from polyvinylidene fluoride (PVDF) fibers, polyamide 6 (PA) fibers, and fibrous structures consisting of a combination of these two materials.