Tension Sensor Research Articles

Study on the Practical Application of Surface Acoustic Wave Yarn Tension Sensor

Nowadays, the commonly used yarn tension sensors cannot meet the requirement well in the textile manufacturing process. So surface acoustic wave (SAW) yarn tension sensor is a good selection to adapt to today's textile manufacturing and improve the production efficiency. First, two key problems of SAW yarn tension sensor in practical application are proposed in this article, one is the construction of the sensor measurement system, the other is the temperature compensation. Then, the integrated design of measurement circuit and measurement structure is implemented and introduced in this article, which improves the accuracy, reliability, and sensitivity of SAW yarn tension sensor. Finally, binary regression analysis method and least squares support vector machine (LSSVM) algorithm optimized by particle swarm optimization (PSO-LSSVM) method are applied to the temperature compensation of SAW yarn tension sensor, which both achieve satisfactory compensation effect. By comparison, PSO-LSSVM method is more convenient and flexible, and still has a large space for improvement. Through those research contents, it can be concluded that the design and implementation of the measurement system lay a foundation for the practical application of SAW yarn tension sensor, the research of temperature compensation is of great significance to the wide application of the sensor.

Sensitivity Optimization of Surface Acoustic Wave Yarn Tension Sensor Based on Elastic Beam Theory

The measurement of yarn tension has a direct impact on the product quality and production efficiency in the textile manufacturing process, and the surface acoustic wave (SAW) yarn tension sensor is a good option for detecting the yarn tension. For SAW yarn tension sensors, sensitivity is an important indicator to assess their performance. In this paper, a new type of SAW yarn tension sensor based on a simply supported beam structure is studied to improve the sensitivity of the fixed beam SAW yarn tension sensor. The sensitivity analysis method based on elastic beam theory is proposed to illustrate the sensitivity optimization. According to the analysis results, the sensitivity of the SAW yarn tension sensor can be greatly improved by using a simply supported beam structure compared to the s fixed beam structure. Moreover, from the calibration experiment, the sensitivity of the simply supported beam SAW yarn tension sensor is 2.5 times higher than that of the fixed beam sensor.

Soft Multifunctional Porous Sponge Sensor for Pressure and Strain Using Liquid Metal/Polydimethylsiloxane with Silver-Nanowire-Coated Composite.

Compression and tension sensors with a porous structure have attracted attention recently. Porous sponge sensors have the advantage of a wide deformation range owing to their structural characteristics. In this study, a porous sponge structure was prepared by absorbing polydimethylsiloxane (PDMS) into the matrix of porous commercial sugar cubes. A conductive network was formed by coating the outside of the sponge skeleton with silver nanowires (AgNWs), which have a high aspect ratio. In addition, a liquid metal (LM), which does not directly form an electrical network but changes from zero-dimensional to one-dimensional under an external force was introduced into this porous sponge structure. The effects of the LM on the sensor sensitivity to pressure and strain were analyzed by comparing the electrical resistance changes of PDMS/AgNW and LM/PDMS/AgNW sponge sensors under tension and pressure. This study shows that the use of a porous structure and an LM may be useful for future wearable sensor design.

Vinculin transmits high-level integrin tensions that are dispensable for focal adhesion formation

Focal adhesions (FAs) transmit force and mediate mechanotransduction between cells and the matrix. Previous studies revealed that integrin-transmitted force is critical to regulate FA formation. As vinculin is a prominent FA protein implicated in integrin tension transmission, this work studies the relation among integrin tensions (force), vinculin (protein), and FA formation (structure) by integrin tension manipulation, force visualization and vinculin knockout (KO). Two DNA-based integrin tension tools are adopted: tension gauge tether (TGT) and integrative tension sensor (ITS), with TGT restricting integrin tensions under a designed Ttol (tension tolerance) value and ITS visualizing integrin tensions above the Ttol value by fluorescence. Results show that large FAs (area >1 μm2) were formed on the TGT surface with Ttol of 54 pN but not on those with lower Ttol values. Time-series analysis of FA formation shows that focal complexes (area <0.5 μm2) appeared on all TGT surfaces 20 min after cell plating, but only matured to large FAs on TGT with Ttol of 54 pN. Next, we tested FA formation in vinculin KO cells on TGT surfaces. Surprisingly, the Ttol value of TGT required for large FA formation is drastically decreased to 23 pN. To explore the cause, we visualized integrin tensions in both wild-type and vinculin KO cells using ITS. The results showed that integrin tensions in FAs of wild-type cells frequently activate ITS with Ttol of 54 pN. With vinculin KO, however, integrin tensions in FAs became lower and unable to activate 54 pN ITS. Force signal intensities of integrin tensions reported by 33 and 43 pN ITS were also significantly reduced with vinculin KO, suggesting that vinculin is essential to transmit high-level integrin tensions and involved in transmitting intermediate-level integrin tensions in FAs. However, the high-level integrin tensions transmitted by vinculin are not required by FA formation.

Transgenic force sensors and software to measure force transmission across the mammalian nuclear envelope in vivo.

Nuclear mechanotransduction is a growing field with exciting implications for the regulation of gene expression and cellular function. Mechanical signals may be transduced to the nuclear interior biochemically or physically through connections between the cell surface and chromatin. To define mechanical stresses upon the nucleus in physiological settings, we generated transgenic mouse strains that harbour FRET-based tension sensors or control constructs in the outer and inner aspects of the nuclear envelope. We knocked-in a published esprin-2G sensor to measure tensions across the LINC complex and generated a new sensor that links the inner nuclear membrane to chromatin. To mitigate challenges inherent to fluorescence lifetime analysis in vivo, we developed software (FLIMvivo) that markedly improves the fitting of fluorescence decay curves. In the mouse embryo, the sensors responded to cytoskeletal relaxation and stretch applied by micro-aspiration. They reported organ-specific differences and a spatiotemporal tension gradient along the proximodistal axis of the limb bud, raising the possibility that mechanical mechanisms coregulate pattern formation. These mouse strains and software are potentially valuable tools for testing and refining mechanotransduction hypotheses in vivo.

Measurement of axial motion yarn tension based on transverse vibration frequency

In the process of textile production, the detection of yarn tension is very important to ensure product quality. In order to detect yarn tension efficiently and conveniently, a non-contact detection method based on transverse frequency was established. Firstly, the governing equation of yarn motion was derived by using the Hamilton principle and solved by the Galerkin truncation method. Then, the natural frequencies of yarns with different linear density were calculated according to the yarn characteristic equation. Finally, the fitting formulas of tension, speed, and frequency of yarn axial motion were derived. By measuring the natural frequency of yarn, the yarn tension could be calculated conveniently and quickly. A high-speed camera was used to measure the transverse vibration displacement of yarn and detect the free vibration frequency of yarn. Through experiments, the results of tension sensor and yarn tension detection based on vibration frequency were compared, and the results show that the error was within 5%, which verifies the effectiveness and accuracy of this method.

Filopodial adhesive force in discrete nodes revealed by integrin molecular tension imaging

Filopodia are narrow cell extensions involved in various physiological processes. Integrins mediate filopodia adhesion and likely transmit adhesive force to regulate filopodia formation and functions, but the force is extremely weak to study and remains poorly understood. Using integrative tension sensor (ITS), we imaged filopodia adhesive force at the single molecular tension level and investigated the force dynamics and sources. Results show that filopodia integrin tension (FIT) is generated in discrete foci (force nodes) along single filopodia with a spacing of ∼1μm. Inhibitions of actin polymerization or myosin II activity markedly reduced FIT signals in force nodes at filopodia tips and at filopodia bases, respectively, suggesting differential force sources of FIT in the distal force nodes and proximal ones in filopodia. Using two ITS constructs with different force thresholds for activation, we showed that the molecular force level of FIT is greater at filopodia bases than that at filopodia tips. We also tested the role of vinculin and myosin X in the FIT transmission. With vinculin knockout in cells, filopodia and associated force nodes were still formed normally, suggesting that vinculin is dispensable for the formation of filopodia and force nodes. However, vinculin is indeed required for the transmission of strong FIT (capable of rupturing DNA in a shear conformation), as the strong FIT vanished in filopodia with vinculin knockout. Co-imaging of FIT and myosin X shows no apparent co-localization, demonstrating that myosin X is not directly responsible for generating FIT, despite its prominent role in filopodium elongation.

The Biomechanical Screening Game between Visitor Power and Staminode Operative Strength of Delphinium caeruleum (Ranunculaceae).

During the evolution of angiosperm flowers, some floral traits may undergo certain changes in order to participate in screening. The stamens and pistils of Delphinium caeruleum are covered by two “door-like” staminodes, the evolutionary function of which, however, is quite unknown. In this study, we investigated whether D. caeruleum staminodes acted as visitor filters by assessing the respective strengths of staminodes and visitor insects (six bee species). We measured the operative strength required to open the staminodes and the strength that insects were capable of exerting using a biological tension sensor. Furthermore, we compared the strength required to open staminodes at different phases of the flowering period (male and female phases) and the strength of different visitors (visitors and non-visitors of D. caeruleum). The results showed that the strength needed to open staminodes in the male phase was significantly higher than that in the female phase. There was no significant difference between the strength exerted by visitors and required by staminodes of D. caeruleum in the male phase, but the visitor strength was significantly higher than that required to open staminodes in the female phase flowers. The strength of non-visitors was significantly lower than that required to open staminodes in the male phase. Furthermore, there was a significant positive association between the strength and the body weight of the bees. These results highlighted the observation that only strong visitors could press the two staminodes to access the sex organs and achieve successful pollination. Furthermore, these results revealed the function of pollinator screening by the staminodes of D. caeruleum. The biomechanical approach to the study of flowers allowed us to address relevant ecological and evolutionary questions of the plant–pollinator interaction and explore the functional modules within the flower structure in other plant species.

Facile detection of mechanical forces across proteins in cells with STReTCh

SummaryNumerous proteins experience and respond to mechanical forces as an integral part of their cellular functions, but measuring these forces remains a practical challenge. Here, we present a compact, 11-kDa molecular tension sensor termed STReTCh (sensing tension by reactive tag characterization). Unlike existing genetically encoded tension sensors, STReTCh does not rely on experimentally demanding measurements based on Förster resonance energy transfer and is compatible with typical fix-and-stain protocols. Using a magnetic tweezers assay, we calibrate the STReTCh module and show that it responds to physiologically relevant, piconewton forces. As proof of concept, we use an extracellular STReTCh-based sensor to visualize cell-generated forces at integrin-based adhesion complexes. In addition, we incorporate STReTCh into vinculin, a cytoskeletal adaptor protein, and show that STReTCh reports on forces transmitted between the cytoskeleton and cellular adhesion complexes. These data illustrate the utility of STReTCh as a tool for visualizing molecular-scale forces in biological systems.

Flexible unimodal strain sensors for human motion detection and differentiation

Multiple strain sensors are required to identify individual forces/stresses on human joints and recognize how they work together in order to determine the motion’s direction and trajectory. However, current sensors cannot detect and differentiate the individual forces/stresses and their contributions to the motion from the sensors’ electrical signals. To address this critical issue, we propose a concept of unimodal tension, bend, shear, and twist strain sensors with piezoelectric poly L-lactic acid films. We then construct an integrated unimodal sensor (i-US) using the unimodal sensors and prove that the i-US can detect and differentiate individual strain modes, such as tensioning, bending, shearing, and twisting in complex motion. To demonstrate the potential impact of unimodal sensors, we design a sleeve and a glove with the i-US that can capture wrist motions and finger movements. Therefore, we expect unimodal strain sensors to provide a turning point in developing motion recognition and control systems.

A Decrease in the Staminode-Mediated Visitor Screening Mechanism in Response to Nectar Robbers Positively Affects Reproduction in Delphinium caeruleum Jacq. ex Camb. (Ranunculaceae).

Simple SummaryNectar robbers frequently have direct or indirect negative effects on plant reproductive success. However, nectar robbers can also indirectly contribute to the reproductive success of plants in some cases. The negative effects of nectar robbing on plant reproductive success have been widely reported, but the reasons for possible positive effects demand further investigation. Hence, our study was designed to assess the effects of nectar robbers on the reproductive success of Delphinium caeruleum. This will facilitate an understanding of the mutualism between plants and their visitors.Nectar-robbing insects, which are frequently described as cheaters in plant–pollinator mutualisms, may affect plant reproductive fitness by obtaining nectar rewards without providing pollination services. The negative effects of nectar robbing on plant reproductive success have been widely reported, but the reasons for possible positive effects demand further investigation. The goal of the study was to evaluate the effects of nectar robbing on the reproductive success of Delphinium caeruleum. Two staminodes cover the stamens and pistils in the flowers of D. caeruleum, forming a “double door” type of structure that compels pollinators to physically manipulate the staminodes to access the sex organs. In order to explore whether the operative strength required to open the staminodes is affected by actions associated with nectar robbing, we set up five different treatment groups: no nectar robbing, natural nectar robbing, artificial nectar robbing, hole making, and nectar removal. A biological tension sensor was used to measure the operative strength required to open the staminodes in the flowers. We also assessed the effect of nectar robbing on the flower-visiting behavior of pollinators and the effect of nectar robbing on reproductive fitness by the flower. The results showed that the operative strength needed to open staminodes was reduced by nectar robbers but not by artificial nectar robbing, hole making, or nectar removal. The flowers’ continuous visitation rate and visitation frequency by pollinators decreased significantly in robbed flowers. Both the pollen export and pollen deposition in naturally robbed flowers were significantly higher than those in nonrobbed flowers. Our results demonstrate that nectar robbers play an indirect positive role in the reproductive fitness of D. caeruleum flowers by reducing the operative strength of staminodes to promote pollen transfer. The reduction in operative strength of staminodes might be an adaptive mechanism that responds to nectar robbing.

Workflow to develop 3D designed personalized neonatal CPAP masks using iPhone structured light facial scanning

BackgroundContinuous positive airway pressure (CPAP) is a common mode of respiratory support used in neonatal intensive care units. In preterm infants, nasal CPAP (nCPAP) therapy is often delivered via soft, biocompatible nasal mask suitable for long-term direct skin contact and held firmly against the face. Limited sizes of nCPAP mask contribute to mal-fitting related complications and adverse outcomes in this fragile population. We hypothesized that custom-fit nCPAP masks will improve the fit with less skin pressure and strap tension improving efficacy and reducing complications associated with nCPAP therapy in neonates.MethodsAfter IRB approval and informed consent, we evaluated several methods to develop 3D facial models to test custom 3D nCPAP masks. These methods included camera-based photogrammetry, laser scanning and structured light scanning using a Bellus3D Face Camera Pro and iPhone X running either Bellus3D FaceApp for iPhone, or Heges application. This data was used to provide accurate 3D neonatal facial models. Using CAD software nCPAP inserts were designed to be placed between proprietary nCPAP mask and the model infant’s face. The resulted 3D designed nCPAP mask was form fitted to the model face. Subsequently, nCPAP masks were connected to a ventilator to provide CPAP and calibrated pressure sensors and co-linear tension sensors were placed to measures skin pressure and nCPAP mask strap tension.ResultsPhotogrammetry and laser scanning were not suited to the neonatal face. However, structured light scanning techniques produced accurate 3D neonatal facial models. Individualized nCPAP mask inserts manufactured using 3D printed molds and silicon injection were effective at decreasing surface pressure and mask strap pressure in some cases by more than 50% compared to CPAP masks without inserts.ConclusionsWe found that readily available structured light scanning devices such as the iPhone X are a low cost, safe, rapid, and accurate tool to develop accurate models of preterm infant facial topography. Structured light scanning developed 3D nCPAP inserts applied to commercially available CPAP masks significantly reduced skin pressure and strap tension at clinically relevant CPAP pressures when utilized on model neonatal faces. This workflow maybe useful at producing individualized nCPAP masks for neonates reducing complications due to misfit.

Improving inkjet printed flexible angle sensor performance by compression–tension sensor pair compensation

This paper introduces a new method for improved integrated angle sensing in the foldable robot joints (hinges), using low-cost inkjet printed sensors and a novel physical intelligence based compensation approach. Silver nanoparticle angle sensors are inkjet printed on a flexible PET substrate as a hinge material and implemented as pairs of compression and tension side folding individuals into a rigid experimental setup. Resulting combined signals improved the individual sensor responses due to their compensating physical characteristics, and gave the far best performances in the existing literature in terms of linearity, sensor life-time, static and cyclic drift, hysteresis and dynamic dependency. Proposed approach is promising for eliminating the major limitations on the printed sensor use in flexible hinges and paving the way to reliable, fully soft and easy-to-fabricate all-integrated foldable robots.

Tether-Based Localization for Cooperative Ground and Aerial Vehicles

Considering a multi-robot system composed of a ground vehicle and a multi-copter connected each other with a tether, it is crucial for them to know their relative positions in order to carry out any operating task. Localization is usually accomplished by using GPS in outdoor environments. However, such a system does not work in indoor and more generally in so-called GPS denied environments. We investigated a solution which exploits the catenary configuration assumed by tether and does not require any computationally demanding resource or complex cable tension sensors. Different approaches have been experimentally tested, compared and validated with classical localization systems in both indoor and outdoor environments.

Cooperative Multilift Slung Load Transportation Using Haptic Admittance Control Guidance

This paper presents the first haptically guided cooperative small unmanned aircraft system payload transport system with experimental validation. A team of five quadrotors is connected with individual tethers to an instrumented payload. A user issues haptic guidance commands by applying force on the slung payload. The system estimates user-applied force and direction from inline tension sensors in real time. This force updates the virtual dynamics of an admittance controller to execute the desired trajectory of the payload in the direction of the applied force. A centralized payload controller commands quadrotor trajectories to track the admittance controller trajectory. Custom open-source autopilot software tracks user commands by translating each quadrotor to pull on the tethers in a manner that collectively moves the payload according to user input force. Simulation and experimental flight-test results in a netted facility validate the system with a user applying force directly on the slung payload to guide it.

A comparison of precision and conventional irrigation in corn production in Southeast Alabama

Adoption of water-conservation irrigation practices could potentially reduce water and energy use and increase profitability, as well as protect the environment. Precision irrigation consisting of soil sensors (SS) for irrigation scheduling and variable rate irrigation (VRI) was compared with conventional uniform irrigation (URI). The study was conducted in South Alabama during the 2018 and 2019 corn growing seasons. The SS-VRI and URI treatments spanned the length of the field and were compared across five different management zones (MZ) that exhibited soil and terrain differences. Soil water tension sensors were installed on each MZ-treatment area to monitor hourly soil water changes. Results showed that on the two zones covering 55% of the study field, MZ 1 and MZ 2, the SS-VRI treatment, on a two-year average, resulted in 26% less irrigation water applied compared to the URI treatment; however, there were no statistical differences between yields or yield variability among treatments. Even though in MZ 4, there was not a substantial difference in irrigation water applied among treatments, soil sensors increased the precision of irrigation rate determination during the peak of high crop water demand. Findings from this study showed that as rainfall amount and distribution change over a crop growing period, soil sensor-based irrigation scheduling could be used to prevent over- or under irrigation. With proper management, the combination of soil sensors and VRI provides farmers with the opportunity to reduce water use, while increasing or maintaining yields; however, farmers must consider the investment and operating costs relative to the benefits.

Methods of solving in‐band ripples and out‐of‐band suppression for yarn tension sensor based on surface acoustic wave

The two key problems of the in-band ripples and out-of-band suppression are proposed in the design of the SAW yarn tension sensor and the methods of decreasing them are achieved. The unbalanced split-electrode interdigital transducers (IDT) are designed so that the total phase of the regenerated reflection wave and mass load feedback is close to 180°, leading to an effective reduction of the in-band ripples effect characterised by the sensor frequency response. The engraved bi-directional slots on the back of the substrate can block the propagation path of the bulk acoustic wave (BAW) to a certain extent, reducing the influence of BAW propagation and suppressing the out-of-band suppression of the frequency response. The experimental results show that the SAW yarn tension sensor with the unbalanced split-electrode IDT can reduce the in-band ripples from 23.34 to 0.93 dB, and the engraved bi-directional slots can suppress the out-of-band suppression from 28.03 to 7.71 dB.

Dystrophin missense mutations alter focal adhesion tension and mechanotransduction

Dystrophin is an essential muscle protein that contributes to cell membrane stability by mechanically linking the actin cytoskeleton to the extracellular matrix via an adhesion complex called the dystrophin-glycoprotein complex. The absence or impaired function of dystrophin causes muscular dystrophy. Focal adhesions (FAs) are also mechanosensitive adhesion complexes that connect the cytoskeleton to the extracellular matrix. However, the interplay between dystrophin and FA force transmission has not been investigated. Using a vinculin-based bioluminescent tension sensor, we measured FA tension in transgenic C2C12 myoblasts expressing wild-type (WT) dystrophin, a nonpathogenic single nucleotide polymorphism (SNP) (I232M), or two missense mutations associated with Duchenne (L54R), or Becker muscular dystrophy (L172H). Our data revealed cross talk between dystrophin and FAs, as the expression of WT or I232M dystrophin increased FA tension compared to dystrophin-less nontransgenic myoblasts. In contrast, the expression of L54R or L172H did not increase FA tension, indicating that these disease-causing mutations compromise the mechanical function of dystrophin as an FA allosteric regulator. Decreased FA tension caused by these mutations manifests as defective migration, as well as decreased Yes-associated protein 1 (YAP) activation, possibly by the disruption of the ability of FAs to transmit forces between the extracellular matrix and cytoskeleton. Our results indicate that dystrophin influences FA tension and suggest that dystrophin disease-causing missense mutations may disrupt a cellular tension-sensing pathway in dystrophic skeletal muscle.

Förster resonance energy transfer efficiency of the vinculin tension sensor in cultured primary cortical neuronal growth cones.

.Significance: Interaction of neurons with their extracellular environment and the mechanical forces at focal adhesions and synaptic junctions play important roles in neuronal development.Aim: To advance studies of mechanotransduction, we demonstrate the use of the vinculin tension sensor (VinTS) in primary cultures of cortical neurons. VinTS consists of TS module (TSMod), a Förster resonance energy transfer (FRET)-based tension sensor, inserted between vinculin’s head and tail. FRET efficiency decreases with increased tension across vinculin.Approach: Primary cortical neurons cultured on glass coverslips coated with poly-d-lysine and laminin were transfected with plasmids encoding untargeted TSMod, VinTS, or tail-less vinculinTS (VinTL) lacking the actin-binding domain. The neurons were imaged between day in vitro (DIV) 5 to 8. We detail the image processing steps for calculation of FRET efficiency and use this system to investigate the expression and FRET efficiency of VinTS in growth cones.Results: The distribution of fluorescent constructs was similar within growth cones at DIV 5 to 8. The mean FRET efficiency of TSMod () in growth cones was higher than the mean FRET efficiency of VinTS () and VinTL () (). While small, the difference between the FRET efficiency of VinTS and VinTL was statistically significant (), suggesting that vinculin is under low tension in growth cones. Two-hour treatment with the Rho-associated kinase inhibitor Y-27632 did not affect the mean FRET efficiency. Growth cones exhibited dynamic changes in morphology as observed by time-lapse imaging. VinTS FRET efficiency showed greater variance than TSMod FRET efficiency as a function of time, suggesting a greater dependence of VinTS FRET efficiency on growth cone dynamics compared with TSMod.Conclusions: The results demonstrate the feasibility of using VinTS to probe the function of vinculin in neuronal growth cones and provide a foundation for studies of mechanotransduction in neurons using this tension probe.

Antibacterial easy adjustable woven compression bandage for venous leg ulcers

The proposed study aims in first part to discuss the structure and behavior of short-stretch cotton woven compression bandage (WCB), and in second part the production and properties of multifunctional WCB. The bandage includes an integrated tension sensor, which causes a change in the spacing of colored threads during its deformation. The motivation of this research was to investigate the optimum techniques for compression therapy using a modified construction of cotton WCB as a tensiometer. The aim of second part is focused on an industrial product which has the easy adjustable compression and antibacterial properties. Multifunctional WCB can be produced by two methods, the first was using highly twisted warp yarns (ply twist 1800 to 2200 twist/m) and the weft yarns will be treated with silver Nano-particles (NPs). The second method was post-treatment of the WCB with three concentrations of zinc oxide NPs 1–3 % in powder form with 15 g/L acrylic binder. Silver NPs coated yarns showed a comparable antibacterial activity on both tested bacterial strains ( Escherichia coli and Staphylococcus aureus) using quantitative and qualitative test methods. The WCB tested samples achieved 95–99% bacteria reduction, the nanoparticles size and its distribution were confirmed by the Zetasizer Nano, the scanning electron microscopy (SEM), and the energy dispersive X-ray spectroscopy (EDXS). The practical bandage pressure by PicoPress showed significant deviations compared with theoretical pressure calculated by Laplace’s equation ranges ±0.68 to ±15.64% especially at the highest extension levels.