Magneto-Mechanical Coupling in Magneto-Active Elastomers.

In the present work, the magneto-mechanical coupling in magneto-active elastomers is investigated from two different modeling perspectives: a micro-continuum and a particle-interaction approach. Since both strategies differ significantly in their basic assumptions and the resolution of the problem under investigation, they are introduced in a concise manner and their capabilities are illustrated by means of representative examples. To motivate the application of these strategies within a hybrid multiscale framework for magneto-active elastomers, their interchangeability is then examined in a systematic comparison of the model predictions with regard to the magneto-deformation of chain-like helical structures in an elastomer surrounding.

Determination of the Entire Stent Surface Area by a New Analytical Method.

Stenting is a widely used treatment procedure for coronary artery disease around the world. Stents have a complex geometry, which makes the characterization of their corrosion difficult due to the absence of a mathematical model to calculate the entire stent surface area (ESSA). Therefore, corrosion experiments with stents are mostly based on qualitative analysis.

Enhanced Digital Gradient Sensing Using Backlight Digital Speckle Target.

Digital gradient sensing (DGS) is a non-contact and full-field optical measurement technique, which assesses mechanical behaviors of transparent materials or specular structures by measuring angular deflections of light rays. However, owing to the poor light-gathering capability of its imaging system, the dynamic performance of DGS is heavily restricted. Here, a method of enhancing the dynamic performance of DGS by improving its speckle target is proposed.

High-throughput measurement of coefficient of thermal expansion using a high-resolution digital single-lens reflex camera and digital image correlation.

High-throughput measurement of thermal deformation and determination of coefficient of thermal expansion (CTE) using a high-resolution digital single lens reflex (DSLR) camera and digital image correlation (DIC) is described. To mitigate the mosaic effect caused by the Bayer filter of DSLR cameras, a color image pre-processing method, which adjusts the brightness and equalizes the color channels of the raw image, is carried out. In addition, a Gaussian pre-filtering step is adopted for denoising the images captured with DSLR cameras to enhance the subpixel registration accuracy.

Three-dimensional architecture of rabbit M. soleus during growth.

Muscle architecture has a significant influence on the mechanical properties of skeletal muscles. Important parameters include the fascicle length, the angle of pennation, the physiological cross-sectional area (PCSA) as well as aponeurosis and tendon dimensions. During growth, skeletal muscles have to react to an increasing body mass and size demanding adaptations in muscle dimensions.

3D finite element models from serial section histology of skeletal muscle tissue - The role of micro-architecture on mechanical behaviour.

In this contribution we create three-dimensional (3D) finite element models from a series of histological sections of porcine skeletal muscle tissue. Image registration is performed on the stained sections by affinely aligning them using auxiliary markers, followed by image segmentation to determine muscle fibres and the extracellular matrix in each section, with particular regard to the continuity of the fibres through the stack. With this information, 3D virtual tissue samples are reconstructed, discretised, and associated with appropriate non-linear elastic anisotropic material models.

Bio-heat response of skin tissue based on three-phase-lag model.

In this article, the thermal response of skin tissue is investigated based on three-phase-lag (TPL) model of heat conduction. The governing equation of bio-heat conduction is established by introducing both the TPL model of heat conduction and a modified energy conservation equation. The analytical solution is obtained by adopting the method of separation of variables and a parametric study on temperature responses in TPL model is carried out.

Consideration of stiffness of wall layers is decisive for patient-specific analysis of carotid artery with atheroma.

The paper deals with the impact of chosen geometric and material factors on maximal stresses in carotid atherosclerotic plaque calculated using patient-specific finite element models. These stresses are believed to be decisive for the plaque vulnerability but all applied models suffer from inaccuracy of input data, especially when obtained in vivo only. One hundred computational models based on ex vivo MRI are used to investigate the impact of wall thickness, MRI slice thickness, lipid core and fibrous tissue stiffness, and media anisotropy on the calculated peak plaque and peak cap stresses.

Vibration Analysis of Post-Buckled Thin Film on Compliant Substrates.

Buckling stability of thin films on compliant substrates is universal and essential in stretchable electronics. The dynamic behaviors of this special system are unavoidable when the stretchable electronics are in real applications. In this paper, an analytical model is established to investigate the vibration of post-buckled thin films on a compliant substrate by accounting for the substrate as an elastic foundation.

Revealing the Plastic Mode of Time-Dependent Deformation of a LiTaO Single Crystal by Nanoindentation.

Recently, instrumental nanoindentation has been widely applied to detect time-dependent plastic deformation or creep behavior in numerous materials, particularly thin films and heterogeneous materials. However, deformation mechanism at nanoindentation holding stage has not been well revealed hitherto. In the current work, nanoindentation holding tests with high loads were performed on a brittle LiTaO single crystal.

Mechano-geometrical skeletal muscle fibre characterisation under cyclic and relaxation loading.

In the present work, mechano-geometrical characterisations of skeletal muscle fibres in two different deformation states, namely, axial tension and axial compression, were realised. In both cases, cyclic and relaxation tests were performed. Additionally, the changes in the volume of the fibres during deformation were recorded to obtain more detailed information about the muscle fibre load transfer mechanisms.

In vivo panoramic human skin shape and deformation measurement using mirror-assisted multi-view digital image correlation.

Panoramic shape and deformation measurements of human skin in vivo may provide important information for biomechanical analysis, exercise guidance and medical diagnosis. This work proposes the application of an advanced mirror-assisted multi-view digital image correlation (DIC) method for dynamic measurements of 360-deg shape and deformation of human body parts in vivo. The main advantage of this method consists in its capabilities to perform full-panoramic non-contact measurements with a single pair of synchronized cameras and two planar mirrors thus representing a lean yet effective alternative to conventional multi-camera DIC systems in 'surrounding' configuration.

Stiffness distribution in natural insect cuticle reveals an impact resistance strategy.

In nature, many insects have evolved hard cuticles to shelter their soft body, which is thought to be the "body-armour" for insects to protect against predators' sharp teeth or dynamic load damage caused by harsh environments. In recent years, researchers have found that the "body-armour" is composed of multi-layer materials with different elastic modulus from inside to outside. The gradient change rule of the formed material modulus reflects the evolutionary history of insect cuticle's adaptation to external changes.

Efficiency of Plasticity Correction in the Hole-Drilling Residual Stress Measurement.

This paper focuses on the analysis of the plasticity effect in the measurement of the residual stress by the hole-drilling method. Relaxed strains were evaluated by the computational simulation of the hole-drilling experiment using the finite element method. Errors induced by the yielding were estimated for uniaxial tension, plane shear stress state and equi-biaxial stress state at various magnitudes of residual stress uniformly distributed along the depth.

Mechanical Terahertz Modulation by Skin-Like Ultrathin Stretchable Metasurface.

The modulation of terahertz plays a key role in realizing the tunable terahertz devices. The concept of flexible and stretchable electronics provides the possibility to dynamically modulate the terahertz with mechanical strain rather than additional electrical components. Here, the mechanical modulation of the terahertz transmission with a freestanding, skin-like, and highly stretchable metasurface is experimentally illustrated.

Strong structural occupation ratio effect on mechanical properties of silicon carbide nanowires.

Materials' mechanical properties highly depend on their internal structures. Designing novel structure is an effective route to improve materials' performance. One-dimensional disordered (ODD) structure is a kind of particular structure in silicon carbide (SiC), which highly affects its mechanical properties.

Advanced Intelligent Control through Versatile Intelligent Portable Platforms.

Deep research and communicating new trends in the design, control and applications of the real time control of intelligent sensors systems using advanced intelligent control methods and techniques is the main purpose of this research. The innovative multi-sensor fusion techniques, integrated through the Versatile Intelligent Portable (VIP) platforms are developed, combined with computer vision, virtual and augmented reality (VR&AR) and intelligent communication, including remote control, adaptive sensor networks, human-robot (H2R) interaction systems and machine-to-machine (M2M) interfaces. Intelligent decision support systems (IDSS), including remote sensing, and their integration with DSS, GA-based DSS, fuzzy sets DSS, rough sets-based DSS, intelligent agent-assisted DSS, process mining integration into decision support, adaptive DSS, computer vision based DSS, sensory and robotic DSS, are highlighted in the field of advanced intelligent control.

The optimal controller design framework for PID-based vibration active control systems via non-probabilistic time-dependent reliability measure.

Vibration control is a significant problem in practical engineering. Because of the uncertainties in practical engineering, the controllers designed according to the deterministic systems have the possibility of failure when applied to practical systems. Taking the widely-used PID control as an example, a framework for designing PID controllers considering the time-dependent reliability (TDR for short) of practical systems with interval uncertainties is proposed in this paper.

Hierarchically structured diamond composite with exceptional toughness.

The well known trade-off between hardness and toughness (resistance to fracture) makes simultaneous improvement of both properties challenging, especially in diamond. The hardness of diamond can be increased through nanostructuring strategies, among which the formation of high-density nanoscale twins - crystalline regions related by symmetry - also toughens diamond. In materials other than diamond, there are several other promising approaches to enhancing toughness in addition to nanotwinning, such as bio-inspired laminated composite toughening, transformation toughening and dual-phase toughening, but there has been little research into such approaches in diamond.

Shell-Forming Stimulus-Active Hydrogel Composite Membranes: Concept and Modeling.

The swelling of active hydrogels combined with passive layers allows the design of shell-forming structures. A shell-like structure offers different properties than a flat structure, e.g.

Exhaustion of Skeletal Muscle Fibers Within Seconds: Incorporating Phosphate Kinetics Into a Hill-Type Model.

Initiated by neural impulses and subsequent calcium release, skeletal muscle fibers contract (actively generate force) as a result of repetitive power strokes of acto-myosin cross-bridges. The energy required for performing these cross-bridge cycles is provided by the hydrolysis of adenosine triphosphate (ATP). The reaction products, adenosine diphosphate (ADP) and inorganic phosphate (P ), are then used-among other reactants, such as creatine phosphate-to refuel the ATP energy storage.

Detection of Anomalous Behavior in Modern Smartphones Using Software Sensor-Based Data.

This paper describes the steps involved in obtaining a set of relevant data sources and the accompanying method using software-based sensors to detect anomalous behavior in modern smartphones based on machine-learning classifiers. Three classes of models are investigated for classification: logistic regressions, shallow neural nets, and support vector machines. The paper details the design, implementation, and comparative evaluation of all three classes.

Microcompression Method for Determining the Size-Dependent Elastic Properties of PMMA Microcapsules Containing -Octadecane.

Accurate evaluation of the shell elastic modulus of microcapsules is of great significance to understanding their performance during production, processing, and applications. In this work, microcompression was employed to investigate the elastic behaviors of a single microcapsule. It was modeled as a microsphere with a core-shell structure compressed between two rigid plates.

Facial Expressions Recognition for Human-Robot Interaction Using Deep Convolutional Neural Networks with Rectified Adam Optimizer.

The interaction between humans and an NAO robot using deep convolutional neural networks (CNN) is presented in this paper based on an innovative end-to-end pipeline method that applies two optimized CNNs, one for face recognition (FR) and another one for the facial expression recognition (FER) in order to obtain real-time inference speed for the entire process. Two different models for FR are considered, one known to be very accurate, but has low inference speed (faster region-based convolutional neural network), and one that is not as accurate but has high inference speed (single shot detector convolutional neural network). For emotion recognition transfer learning and fine-tuning of three CNN models (VGG, Inception V3 and ResNet) has been used.

Impact of Decreased Transmural Conduction Velocity on the Function of the Human Left Ventricle: A Simulation Study.

This study investigates the impact of reduced transmural conduction velocity (TCV) on output parameters of the human heart. In a healthy heart, the TCV contributes to synchronization of the onset of contraction in individual layers of the left ventricle (LV). However, it is unclear whether the clinically observed decrease of TCV contributes significantly to a reduction of LV contractility.