Motion Energy Research Articles

Scaling between volume and runout of rock avalanches explained by a modified Voellmy rheology

Abstract. Rock avalanches reach considerably greater runout lengths than predicted by Coulomb friction. While it has been known for a long time that runout length increases with volume, explaining the increase qualitatively is still a challenge. In this study, the widely used Voellmy rheology is reinterpreted and modified. Instead of adding a Coulomb friction term and a velocity-dependent term, the modified rheology assigns the two terms to different regimes of velocity. While assuming a transition between Coulomb friction and flow at a given velocity is the simplest approach, a reinterpretation of an existing model for the kinetic energy of random particle motion predicts a dependence of the crossover velocity on the thickness of the rock avalanche. Analytical solutions for a lumped mass on a simple 1D topography reveal the existence of a slope-dominated and a height-dominated regime within the regime of flow. In the slope-dominated regime, the kinetic energy at the foot of the slope depends mainly on the slope angle, while the absolute height relative to the valley floor has little effect, and vice versa. Both regimes can be distinguished by the ratio of a length scale derived from the rheology and the length scale of the topography. Long runout occurs in the height-dominated regime. In combination with empirical relations between volume, thickness, and height, the approach based on the random kinetic energy model reproduces the scaling of runout length with volume observed in nature very well.

Low-frequency human motion energy scavenging with wearable tumbler-inspired electromagnetic energy harvesters

Harvesting energy from human motion to power portable electronic devices has attracted widespread attention. However, human motion energy is primarily concentrated in low-frequency range below 5 Hz, which makes it hard to capture with traditional approaches. In this work, a tumbler-inspired electromagnetic energy harvester (T-EMH) is designed to harvest human motion energy. The magnet is placed on the top of the tumbler structure, allowing for easy conversion of irregular human motion into electricity through the tumbler mechanism. A theoretical model is established to predict the energy harvesting performance of T-EMH. Both simulations and experiments were conducted to verify the low-frequency characteristics of T-EMH. The harvested maximum peak voltage is 0.6 V and the maximum average output power can reach 0.55 mW by adjusting the external load. Additionally, human motion tests substantiate T-EMH's capacity to generate a peak power output of 0.86 mW at a running speed of 12 km/h. These results emphasize the promising potential of T-EMH as an effective approach for capturing energy from human motion.

A self-powered intracardiac pacemaker in swine model

Harvesting biomechanical energy from cardiac motion is an attractive power source for implantable bioelectronic devices. Here, we report a battery-free, transcatheter, self-powered intracardiac pacemaker based on the coupled effect of triboelectrification and electrostatic induction for the treatment of arrhythmia in large animal models. We show that the capsule-shaped device (1.75 g, 1.52 cc) can be integrated with a delivery catheter for implanting in the right ventricle of a swine through the intravenous route, which effectively converts cardiac motion energy to electricity and maintains endocardial pacing function during the three-week follow-up period. We measure in vivo open circuit voltage and short circuit current of the self-powered intracardiac pacemaker of about 6.0 V and 0.2 μA, respectively. This approach exhibits up-to-date progress in self-powered medical devices and it may overcome the inherent energy shortcomings of implantable pacemakers and other bioelectronic devices for therapy and sensing.

Joint torque prediction of industrial robots based on PSO-LSTM deep learning

PurposeBecause of the key role of joint torque in industrial robots (IRs) motion performance control and energy consumption calculation and efficiency optimization, the purpose of this paper is to propose a deep learning torque prediction method based on long short-term memory (LSTM) recurrent neural networks optimized by particle swarm optimization (PSO), which can accurately predict the the joint torque.Design/methodology/approachThe proposed model optimized the LSTM with PSO algorithm to accurately predict the IRs joint torque. The authors design an excitation trajectory for ABB 1600–10/145 experimental robot and collect its relative dynamic data. The LSTM model was trained with the experimental data, and PSO was used to find optimal number of LSTM nodes and learning rate, then a torque prediction model is established based on PSO-LSTM deep learning method. The novel model is used to predict the robot’s six joint torque and the root mean error squares of the predicted data together with least squares (LS) method were comparably studied.FindingsThe predicted joint torque value by PSO-LSTM deep learning approach is highly overlapped with those from real experiment robot, and the error is quite small. The average square error between the predicted joint torque data and experiment data is 2.31 N.m smaller than that with the LS method. The accuracy of the novel PSO-LSTM learning method for joint torque prediction of IR is proved.Originality/valuePSO and LSTM model are deeply integrated for the first time to predict the joint torque of IR and the prediction accuracy is verified.

An Integrated Charge Excitation Alternative Current Dielectric Elastomer Generator for Joint Motion Energy Harvesting

AbstractJoint movement is a plentiful source of energy in living organisms; however, it is challenging to harvest due to its multidirectional nature, and effective technologies for harnessing this energy are lacking. In this study, a novel approach is presented to harvest joint motion energy by combining an alternating current dielectric elastomer generator (AC‐DEG) with an electret nanogenerator (ENG). The ACENG‐DEG, utilizing ion hydrogel electrodes and ENG, exhibits remarkable stretchability (860%) and efficiently converts mechanical energy into electrical energy through a stretch‐based mechanism. With only 37 cycles, the device reaches a saturation voltage of 1.18 kV and generates an output charge of 1.96 µC per cycle. Notably, the charge output response speed is approximately four times faster than that of traditional AC‐DEGs. The proposed strategy for harvesting human mechanical energy in this study represents a promising pathway for developing high‐performance energy harvesting devices and self‐powered systems.

On tidal energy in Newtonian two-body motion with infinite initial separation

On tidal energy in Newtonian two-body motion with infinite initial separation

X-Ray Polarization of the Eastern Lobe of SS 433

How astrophysical systems translate the kinetic energy of bulk motion into the acceleration of particles to very high energies is a pressing question. SS 433 is a microquasar that emits TeV γ-rays indicating the presence of high-energy particles. A region of hard X-ray emission in the eastern lobe of SS 433 was recently identified as an acceleration site. We observed this region with the Imaging X-ray Polarimetry Explorer and measured a polarization degree in the range 38%–77%. The high polarization degree indicates the magnetic field has a well-ordered component if the X-rays are due to synchrotron emission. The polarization angle is in the range −12° to +10° (east of north), which indicates that the magnetic field is parallel to the jet. Magnetic fields parallel to the bulk flow have also been found in supernova remnants and the jets of powerful radio galaxies. This may be caused by interaction of the flow with the ambient medium.

Quasi Time-Fuel Optimal Control Strategy for Dynamic Target Tracking

Time and fuel balance is an important topic in the dynamic tracking problem of unmanned systems. In this paper, we propose a quasi time-fuel optimal control strategy (QTFOC) to solve the dynamic tracking problem of a double integrator system, which is capable of multi-target switching tracking tasks, such as the multi-target strike of weapons and the rapid multi-target grabbing of robots on industrial assembly lines. Compared with the previous optimal control algorithms, the proposed controller retains the time-fuel optimal characteristic when switching among multiple dynamic targets, and overcomes the high-frequency oscillation problem by incorporating local linear control region and two nonlinear buffer areas. That is, when switching among multiple dynamic targets, the proposed control strategy enables the corresponding system to achieve desired transient performance and satisfactory steady-state performance simultaneously. In addition, the asymmetry of friction load is further explored, which affects the dynamic performance of the actual system. Extensive experiments based on the visual tracking turntable demonstrate the superiority and feasibility of the proposed method. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Note to Practitioners</i> —This paper was motivated by the problem of multi-target switching tracking, such as the multi-target strike of weapons with vision sensors and the rapid multi-target grabbing of robots on industrial assembly lines. In recent years, various algorithms have been developed for trajectory planning and tracking. However, it is still challenging for unmanned servo system to capture dynamic targets quickly due to the constrains of motion performance, energy, and computational power. In order to reduce the computational burden and obtain ideal response under various physical constraints, a quasi time-fuel optimal control strategy (QTFOC) with analytical solutions is proposed in this paper. First, the static target is extended to the dynamic target by further investigating the traditional time-fuel optimal control theory for double integrator system. Second, to deal with the oscillation problem caused by system disturbances, we incorporate buffer areas and local linear control region into the control algorithm, which makes the system more robust. Third, the system performance is further improved by analyzing the frictional load asymmetry. This algorithm requires small computational resources and can be implemented directly on microcontrollers such as STM32. The experimental results demonstrate the superiority of our proposed method in handling the multi-target switching tracking problem, which can also adjust the response speed weight, making the unmanned system perform better under different operating conditions. Furthermore, the proposed QTFOC can be extended to other unmanned systems, such as trajectory planning and motion control for unmanned vehicles and bionic robots.

Convective boundary layer flow of MHD tangent hyperbolic nanofluid over stratified sheet with chemical reaction

&lt;abstract&gt; &lt;p&gt;We investigated the combined impact of convective boundary conditions, thermal conductivity, and magnetohydrodynamic on the flow of a tangent hyperbolic nanofluid across the stratified surface. Furthermore, the ramifications of Brownian motion, thermophoresis, and activation energy were considered. Heat generation, chemical reactions, mixed convection, thermal conductivity, and other elements were considered when analyzing heat transfer phenomena. The governing equations were converted via similarity transformations into non-dimensional ordinary differential equations in order to analyze the system. Using the shooting method, the problem's solution was determined. We showed the mathematical significance of the temperature, concentration profiles, and velocity of each fluid parameter. These profiles were thoroughly described and shown graphically. The findings demonstrated that as the Weissenberg number and magnetic number increased, the fluid velocity profile decreased. Higher heat generation and thermophoresis parameters resulted in an increase in the temperature profile. Higher Brownian motion and Schmidt parameter values resulted in a drop in the concentration profile. Tables were used to discuss the numerical values of skin friction ($ {C}_{fx} $), Nusselt number ($ {Nu}_{x} $), and Sherwood number ($ S{h}_{x} $). For the greater values of Weissenberg number and mixed convection parameters, skin friction numerical values fell while Nusselt numbers rose.&lt;/p&gt; &lt;/abstract&gt;

Chemical magnetism - surface force to move motors.

If redox reactions occur on the surface of a motor and a current loop arises, then in a non-uniform magnetic field, in addition to the usual magnetic force, such a motor will also be affected by a chemical magnetic force. The chemical magnetic force belongs to the class of surface forces. Here we analyze for the first time the properties of chemical magnets, which consist of three dissimilar metals, as well as the magnetic field generated by a chemical magnet using paramagnetic nanoparticles. The results of the study show that the chemical magnetic force depends on the concentration and type of electrolyte, the pH of the solution, the temperature, and the structure of the chemical magnet. The results obtained can contribute to the creation of devices where chemical energy is directly converted into kinetic energy of motion.

Global existence of weak solutions to a class of higher-order nonlinear evolution equations

&lt;p&gt;This paper deals with the initial boundary value problem for a class of &lt;italic&gt;n&lt;/italic&gt;-dimensional higher-order nonlinear evolution equations that come from the viscoelastic mechanics and have no positive definite energy. Through the analysis of functionals containing higher-order energy of motion, a modified potential well with positive depth is constructed. Then, using the potential well method, and Galerkin method, it has been shown that when the initial data starts from the stable set, there exists a global weak solution to such an evolution problem.&lt;/p&gt;

Evidence of mutual non-verbal synchrony in learners with severe learning disability and autism, and their support workers: a motion energy analysis study.

Some research indicates that neurodivergent people are less likely than "neurotypical" people to adapt their movements to a partner's movements to facilitate interpersonal motor synchrony. Researchers therefore suggest synchrony deficits underlie the social differences associated with autism and other neurodivergences. Intensive Interaction (II) is a client-led approach, where Learning Support Workers (LSW) follow the lead of learners to create balanced and reciprocal interactions. We aimed to examine the balance of synchrony in learners with autism and Severe Learning Disabilities and their LSWs in a special education college where learners had prior experience with II. Using Motion Energy Analysis, we assessed the degree to which each partner acted as a leader, and hence which partner acted as a follower, during moments of close synchrony. Overall, learners and LSWs showed higher than chance synchrony. There were no differences in the degree to which each partner led the moments of synchrony, or the amount pairs synchronized with zero-lag, where there was no delay between each partners' movements. The equal balance of leading and following in the learner and LSW pairs demonstrates that both partners consistently adapted their movements to their partner's movements to facilitate synchrony. The findings tentatively challenge the notion of a synchrony deficit in autism and suggest synchrony can be present in cross-neurotype pairs in comfortable and engaging conditions. We discuss the potential for client-led, movement-based approaches to support smooth interactions across neurotypes.

Prototype Design and Construction of 450 VA Permanent Magnetic Sync Generator for Vertical Axis Wind Power Generator House Scale with Low Wind Speed

Permanent magnet synchronous generator (PMSG) is a mechanical electrical machine that can convert motion energy into electrical energy which has two main parts, namely a rotor using permanent magnets and a stator without an iron core which the machine uses for low and low rotations. load torque used as a generator. The driving force for Wind Power Plants (PLTB) which we know is alternative and renewable power plants, the energy source is wind which continues to exist and is easily available, another reason for the need to develop permanent magnet generators for PLTB is the reduction of petroleum, other fossil energy, subsidies continue to cut materials fuel oil for power generation which increases the price of electricity per KWH as well as a global commitment to reduce greenhouse gas emissions. the need for electricity for the community and the high price of electricity as well as the difficulty of installing electricity with a capacity of 450 VA, this study aims to make a prototype of a laboratory-scale permanent magnet generator for wind power plants for residential homes that allows it to be placed close to the ground, no need to be directed towards the wind. blowing, can generate electricity with wind speed from 2.5 m/s, easy operation and low cost. The research method in this study is to conduct a literature study, conduct a wind source mapping survey from several sources to obtain wind speed data nationally, design a prototype and design a permanent magnet generator prototype and finally simulation with calculation capacity of the prototype. The design of the permanent magnet generator prototype for the Wind Power Plant has 12 poles with a rotor speed of 500 rpm (revolution per minute) with capacity of 450 VA.

基于CFD-DEM耦合中小型气吸红枣捡拾机物料输送仿真试验与验证

To improve the quality of air suction jujube picker, the CFD-DEM coupled method is used to numerically simulate the conveying process of jujube particles and explore the motion state, particle collision and energy loss of jujube particles in the pipeline. The erosion rate is selected as an evaluation index to discuss the influence of wind velocity, bending angle and diameter on the conveying process. The simulation results show that the collisions between jujubes, as well as the collisions between jujubes and pipe wall have an impact on the conveying performance, and the latter is more significant. The erosion rate is positively correlated with the wind velocity, negatively correlated with the pipe diameter, and the bending angle first decreases and then increases. The influence degree of factors on the erosion rate is: wind velocity &gt; bending angle &gt; pipeline diameter. The optimal parameter combination is a wind velocity of 28 m•s-1, a bending angle of 105 °, and a pipe diameter of 130 mm. At this time, the value of erosion rate is the lowest and the number of collisions and energy loss between jujube particles are reduced by 37.3 % and 13.87 % year-on-year, and those between jujube particles and pipe wall are reduced by 17.45 % and 17.61 % year-on-year, respectively. The test results show that the conveying pipe with optimized structural parameters can reduce the jujube skin damage rate by 2.06 %. The results of this study can provide a reference for the design and optimization of the air suction jujube picker.

Anxiety as a Predictor of Movement During a Math Task in Elementary School Children

Anxiety can come in various forms; general anxiety is characterized by feelings of excessive anxiety impacting multiple domains of everyday life, whereas anxiety may also manifest within a single domain (i.e., math anxiety). Those that present with anxiety who also have Autism Spectrum Disorder often exhibit ritualized movement as a coping mechanism for their anxiety. However, the relationship between anxiety and movement has not yet been explored within typically developing children. It is also unclear if the form of anxiety impacts the degree to which children move. In this study, we used Motion Energy Analysis to quantify the relationship between both general and math anxiety and movement during a math flashcards task. Multivariate linear regression analysis was used to determine possible relationships between anxiety and movement. General anxiety significantly contributed to models predicting movement during the math flashcards task, while math anxiety did not. Our results suggest that movement could be an indicator of general anxiety in elementary aged children. KEYWORDS: General Anxiety; Math Anxiety; Elementary; Academics; Motion Energy Analysis; Movement; Ritualized Movement; Mathematics

POTENSI PEMBANGKIT LISTRIK TENAGA MIKROHIDRO DENGAN TURBIN KAPLAN PADA SUNGAI MAMBAL

The Kaplan turbine is a type of reaction turbine that utilizes potential energy to generate motion energy. The Kaplan turbine is very suitable for use in places where the head is low but requires a large discharge. Currently Kaplan turbines are still very little used in Indonesia, especially in Bali. So that it is difficult to obtain specification data relating to Kaplan turbines. Many prototypes are made on a laboratory scale to get maximum results. This study discusses the results of the output voltage, current, power, and efficiency that can be produced by a PLTMH prototype using a Kaplan turbine. This study also discusses the analytical study of the existing hydropower potential, namely, the water flow rate and the height of the water fall (head) of the Mambal River water flow. This prototype test uses a water flow rate of 6 L or 0.006 m^3/s with a guide vane angle of 30 º and a total of 5 runner blades. In the no-load test, the average turbine rotation before being coupled to the generator was 556 rpm, the average turbine rotation after being coupled was 353 rpm. The average result of the largest turbine rotation is 303 rpm, the largest generator rotation result is 499 rpm, the largest generator voltage average result is 5.60 volts, the largest average generator current result is 0.61 Ampere, the result the largest average generator powerKey Words : Prototype of PLTMH, Kaplan Turbine, Water Discharge, Output producedis 1.93 Watt, the largest torque is 0.14 Nm, the largest PLTMH efficiency is 5.1%.

Continuous Melt Spinning of Adaptable Covalently Cross-Linked Self-Healing Ionogel Fibers for Multi-Functional Ionotronics.

Stretchable conductive fibers play key roles in electronic textiles, which have substantial improvements in terms of flexibility, breathability, and comfort. Compared to most existing electron-conductive fibers, ion-conductive fibers are usually soft, stretchable, and transparent, leading to increasing attention. However, the integration of desirable functions including high transparency, stretchability, conductivity, solvent resistance, self-healing ability, processability, and recyclability remains a challenge to be addressed. Herein, a new molecular strategy based on dynamic covalent cross-linking networks is developed to enable continuous melt spinning of the ionogel fiber with the aforementioned properties. As a proof of concept, adaptable covalently cross-linked ionogel fibers based on dimethylglyoximeurethane (DOU) groups (DOU-IG fiber) are prepared. The resultant DOU-IG fiber exhibited high transparency (>93%), tensile strength (0.76MPa), stretchability (784%), and solvent resistance. Owing to the dynamic of DOU groups, the DOU-IG fiber shows high healing performance using near-infrared light. Taking advantage of DOU-IG fibers, multifunctional ionotronics with the integration of several desirable functionalities including sensor, triboelectric nanogenerator, and electroluminescent display are fabricated and used for motion monitoring, energy harvesting, and human-machine interaction. It is believed that these DOU-IG fibers are promising for fabricating the next generation of electronic textiles and other wearable electronics.

Quasi-Zero Stiffness Vibration Sensing and Energy Harvesting Integration Based on Buckled Piezoelectric Euler Beam.

This paper presents a novel quasi-zero stiffness vibration sensing and energy harvesting integration system for absolute displacement measurements based on a buckled piezoelectric Euler beam (BPEB) with quasi-zero stiffness (QZS) characteristics. On one hand, BPEB provides negative stiffness to the system, thus creating a vibration-free point within the system and transforming the absolute displacement measurement problem into a relative motion sensing problem. On the other hand, during the measurement process, the BPEB collects the vibration energy from the system, which can provide electrical energy for low-power relative motion sensing devices and remarkably suppress the frequency range of the jump phenomenon, thereby further expanding the frequency domain measurement range of the sensing system. The research results have shown that this system can measure the absolute motion signal of the tested object in low-frequency vibration with small excitation. By adjusting parameters such as the force-electric coupling coefficient and damping ratio, the measurement accuracy of the sensing system can be improved. Furthermore, the system can convert the mechanical energy of vibrations into electrical energy to power the surrounding low-power sensors or provide partial power. This could potentially achieve self-powering integrated quasi-zero stiffness vibration sensing, offering another approach and possibility for the automation development in wireless sensing systems and the Internet of Things field.

Boosting Sensing Performance of Flexible Piezoelectric Pressure Sensors by Sb Nanosheets and BaTiO3 Nanoparticles Co‐Doping in P(VDF‐TrFE) Nanofibers Mat

AbstractFlexible piezoelectric pressure sensors (FPPS) received a lot of attention because of their prominent performance in body motion detection and energy recovery. However, it has faced a huge challenge in manufacturing FPPS with high sensitivity, low cost, and high flexibility. Herein, a ternary flexible nanofiber composite with Sb nanosheets and BaTiO3 nanoparticles as the fillers of P(VDF‐TrFE) is prepared by electrospinning. An impressive open‐circuit voltage of 17.1 V and short‐circuit current of 4.4 µA is obtained based on the composite nanofiber mat at a pressure of 128 kPa with 2 Hz frequency. The FPPS not only exhibit a high sensitivity of 96 mV kPa−1 but also an ultrafast response time of 2 ms. Excellent flexibility and reliability are demonstrated by the unchanged open‐circuit voltage after 2400 cycles. The enhanced FPPS performance is owed to the interfacial polarization effect at the inorganic filler‐organic matrix interface, which also enhances the ferroelectric and dielectric properties. The present FPPS is further confirmed to be a real‐time motion monitor and voice recognizer, which can distinguish various actions and sounds according to distinct output voltage signals and is expected to be used in virtual reality devices, robotic electronic skin, haptic simulation, artificial throat, etc.

Magnetostrictive wires-epoxy resin composite structures for human motion energy harvesting

Encapsulation of magnetostrictive alloy wires in epoxy resin has great potential for energy harvesting and can be applied to energy harvesting in human motion. In this work, a magnetostrictive wire-epoxy resin arch composite structure was proposed for harvesting energy generated by foot motion. A prestress was introduced during the resin curing process, and the relationship between the output voltage and material properties was derived based on the Villari effect. Three kinds of Fe-based magnetostrictive wires were prepared and their magnetic properties were measured, then a prototype single-layer arch composite structure was fabricated and an experimental platform was built for testing, and the amplitude of the output open-circuit voltage could reach 936 mV under an impact pressure of 750 N, which proved that the Fe–Ga alloy composite structure was superior to Fe–Co and Fe–Ni alloys in energy harvesting. The double-layer arch-shaped Fe–Ga composite structures energy harvesting prototype outputs a maximum voltage of up to 940 mV in foot energy harvesting experiments, and collected a maximum power of up to 2.45 mW at a step frequency of 3.5 Hz. Consequently, this work emphasized the feasibility of magnetostrictive alloy-epoxy composite structures for energy harvesting in human motion and the potential for developing new ways of energy harvesting.