Tapping Cycle Research Articles

Enhancing the piezoelectric coefficient of SrTiO3 nanocubes and PVDF film deposited by supersonic spraying for energy-harvesting nanogenerators

Many perovskites and their piezoelectric composites have been investigated for harvesting ambient mechanical energy over the past two decades; however, the prospects for their commercialization appear remote because of several practical challenges. Therefore, highly scalable supersonic cold-spraying technology was used to fabricate flexible piezoelectric films of poly(vinylidene fluoride) (PVDF) and a novel perovskite SrTiO3 (ST). Substantial shear stress was exerted on PVDF during cold spraying owing to the hydrothermally synthesized SrTiO3 nanocubes and supersonic velocity, and the resulting film delivered an effective piezoelectric coefficient (69.6 pm·V−1) as confirmed by piezo-response force microscopy. As a result, the piezoelectric nanogenerator yields a maximum power of 130 µW at a load resistance of 0.9 MΩ. The composite film exhibited durability for 21,000 tapping cycles with 20 N applied force and 7 Hz frequency. The flexibility endurance was confirmed from 3000 bending cycles. PENG attached to knee delivered 1 and 2.3 V on bending to 45 and 90°, respectively. After electrical poling, the PENG was subjected to a 20 N tapping force that yielded a piezopotential of 31 V. To the best of our knowledge, this is the first time piezoelectricity was obtained using an ST/PVDF composite via mechanical energy harvesting. The flexible PENG film deposited by cold-spraying shows good potential for wearable self-powered devices.

Printed and Stretchable Triboelectric Energy Harvester Based on P(VDF‐TrFE) Porous Aerogel

AbstractDeveloping energy harvesting devices is crucial to mitigate the dependence on conventional and rigid batteries in wearable electronics, ensuring their autonomous operation. Nanogenerators offer a cost‐effective solution for enabling continuous operation of wearable electronics. Herein, this study proposes a novel strategy that combines freeze‐casting, freeze‐drying, and printing technologies to fabricate a fully printed triboelectric nanogenerator (TENG) based on polyvinylidene fluorid‐etrifluoroethylene P(VDF‐TrFE) porous aerogel. First, the effects of porosity and poling on the stretchability and energy harvesting capabilities of P(VDF‐TrFE) are investigated, conducting a comprehensive analysis of this porous structure's impact on the mechanical, ferroelectric, and triboelectric properties compared to solid P(VDF‐TrFE) films. The results demonstrate that structural modification of P(VDF‐TrFE) significantly enhances stretchability increasing it from 7.7% (solid) to 66.4% (porous). This modification enhances output voltage by 66% and generated charges by 48% for non‐poled P(VDF‐TrFE) porous aerogel films compared to their non‐poled solid counterparts. Then, a fully printed TENG is demonstrated using stretchable materials, exhibiting a peak power of 62.8 mW m−2and an average power of 9.9 mW m−2over 100 tapping cycles at 0.75 Hz. It can illuminate light‐emitting diodes (LEDs) through the harvesting of mechanical energy from human motion. This study provides a significant advance in the development of energy harvesting devices.

Supersonically Sprayed Cobalt Titanate and PVDF for Flexible Piezoelectric Nanogenerators

Piezoelectric nanogenerators (PENGs) are the core components of self-powered devices used in sensors, ecofriendly wearable gadgets, and biomedical implants. This study introduces and demonstrates a flexible PENG with supersonically cold-sprayed films of cobalt titanate (CTO) and polyvinylidene fluoride (PVDF). An electrically poled PENG produces a maximum output voltage of 34.8 V under a tapping force of 20 N, whereas a CTO/PVDF-based PENG exhibits 25.4 V across a loading resistance ( R L ) of 50 MΩ and generates a short-circuit current of 30 μA at 0.1 MΩ. Furthermore, the maximum power density is 25 μW·cm-2 at R L = 0.6 MΩ. Cyclic tapping and bending test results show that open-circuit voltages (Voc) of 25.4 and 5.8 V are produced under the tapping cycle of N tap = 4200 and bending cycle of N bend = 750 , respectively, confirming the mechanical durability of the PENG. Thus, the potential of CTO/PVDF films for use in PENGs with various functionalities can be confirmed based on the V oc values generated from bending, mobile tapping, walking, and lifting movements.

Beta-phase transformation of polyvinylidene fluoride with supersonically sprayed ZnSnO3 cuboids for flexible piezoelectric nanogenerators

Flexible self-powered electromechanical devices, such as piezoelectric nanogenerators (PENGs), which are used in wearable and implantable devices, are emerging as state-of-the-art clean energy sources. In this study, a scalable supersonic spraying technique was used to prepare flexible piezocomposite films of polyvinylidene fluoride (PVDF) and hydrothermally synthesized ZnSnO3 (ZSO) cubes for PENGs. Raman spectra confirmed that the transformation of the α-phase of PVDF to its β-phase was induced by the shear stress generated between the ZSO particles and PVDF polymer during supersonic spraying. The optimized sample comprising 0.43 g of ZSO cubes and 1 g of PVDF produced a maximum piezopotential of 41.5 V and a short-circuit current, Isc, of 52.5 μA. A maximum power density of 50.6 μW cm−2 was obtained at a loading resistance of 0.4 MΩ, which matched the impedance of the PENG. Long-term tapping and bending cycles of Ntap = 4200 and Nbend = 600 yielded piezopotentials of 40.5 and 1.7 V, respectively. In addition, electrical poling for 2 h increased the piezopotential to 52 V owing to the alignment of the ferroelectric dipoles in the PVDF.

Analysis of the impact of carbon dissolution and energy transport on the flow in the hearth of an ironmaking blast furnace by transient CFD simulations

In the ironmaking blast furnace, layers of coke, ferrous burden (sinter, pellets, lump ore) and additions are heated by an uprising gas flow. While the layers are descending, the iron ore is reduced and begins to melt. The liquid products slag and hot metal trickle downwards into the hearth, where they prevail as two immiscible phases filling the voids within the coke bed and with the slag floating on top of the hot metal. As the hearth is lined with carbon blocks, which are eroded by the passing hot metal flow, this region has a major impact on the campaign length of the blast furnace. The blast furnace hearth is drained intermittently by opening the taphole and closing it to end the tap. Hence, the fluid phases in the hearth are in a transient state with the liquid levels constantly varying and the flow conditions being determined by the tapping/non-tapping state. In addition, dissolution of carbon into the hot metal and cooling applied to the refractory affect the local hot metal flow. This work presents a CFD-model, which is capable to calculate the multiphase flow in a 3-dimensional hearth at an industrial scale. The tool allows for modelling of the transient transport processes, including multiple tapping cycles by utilizing new approaches for the transition between tapping/non-tapping and the inflow of liquids into the hearth. Furthermore, the dissolution of carbon, energy transport in the liquids and the locally varying density of hot metal depending on temperature and carbon content are included. With this approach, thermal stratification and circulation effects induced by buoyancy can be described over a period of nearly 8 h, thus covering 4 tapping cycles. In addition to an analysis of energy, carbon content and velocity fields, the transient evolution of tapped hot metal properties (temperature, carbon) are obtained and compared to available plant data.

Motor cortex excitability is reduced during freezing of upper limb movement in Parkinson’s disease

Whilst involvement of the motor cortex in the phenomenon of freezing in Parkinson’s disease has been previously suggested, few empiric studies have been conducted to date. We investigated motor cortex (M1) excitability in eleven right-handed Parkinson’s disease patients (aged 69.7 ± 9.6 years, disease duration 11.2 ± 3.9 years, akinesia-rigidity type) with verified gait freezing using a single-pulse transcranial magnetic stimulation (TMS) repetitive finger tapping paradigm. We delivered single TMS pulses at 120% of the active motor threshold at the ‘ascending (contraction)’ and ‘descending (relaxation)’ slope of the tap cycle during i) regular tapping, ii) the transition period of the three taps prior to a freeze and iii) during freezing of upper limb movement. M1 excitability was modulated along the tap cycle with greater motor evoked potentials (MEPs) during ‘ascending’ than ‘descending’. Furthermore, MEPs during the ‘ascending’ phase of regular tapping, but not during the transition period, were greater compared to the MEPs recorded throughout a freeze. Neither force nor EMG activity 10–110 s before the stimulus predicted MEP size. This piloting study suggests that M1 excitability is reduced during freezing and the transition period preceding a freeze. This supports that M1 excitability is critical to freezing in Parkinson’s disease.

A new screening test for idiopathic normal pressure hydrocephalus using bimanual coordination: A preliminary study.

The clinical spectrum of idiopathic normal pressure hydrocephalus (iNPH) comprises the triad of gait disturbance, cognitive impairment, and urinary incontinence. However, motor abnormalities involving the upper extremities in iNPH patients have few quantitative studies. The present study was designed to quantitatively assess bimanual tapping tasks in iNPH patients and to compare with the control groups. The subjects were divided into three groups: iNPH patients, older healthy group, and younger healthy group. The tasks were three synchronization finger-to-thumb tapping tasks with the auditory stimuli specified at 1 Hz by metronome: unilateral, bimanual simultaneous, and bimanual alternate. Two-way ANOVA was used to compare the outcomes of the three errors (absolute error: AE, variable error: VE, and constant error: CE) for tapping cycles. In the iNPH group, the absolute and variable errors increased in bimanual alternate tapping task with statistical significance (AE: p < 0.05 and VE: p < 0.05). There were no significant differences in errors between the older and young healthy groups (AE: p = 0.62, CE: p = 1.00 and VE: p = 0.31). We could quantitatively evaluate the bimanual coordination on iNPH patients using the bimanual alternate tapping task, potentially useful for evaluating patients unable to walk.

Variability in Ferroalloy Furnace Tapping – Insights from Modelling

During tapping of pyrometallurgical smelters, molten products from the furnace operation are periodically removed from the vessel. Variations in the quantities of alloy and slag obtained from each tap are undesirable and can cause disruption to upstream and downstream operations, resulting in economic losses and safety risks to plant personnel. In the present work an integrated reduced-order model of a ferroalloy furnace tapping system was used to assess the sensitivity of the process to various operating parameters, and describe the statistical impact of random changes in the system over a large number of tapping cycles. The effect of implementing simple control measures to determine the best point to stop a tap is also presented.

Effects of Stimulus Intensity and Frequency on the Force and Timing of Sensorimotor Synchronisation

Abstract We report an experiment to investigate possible vestibular effects on finger tapping to an auditory anapaest rhythm. In a sample of 10 subjects, index finger acceleration and tapping force were recorded along with extensor/flexor activity and the associated electroencephalographic activity measured at central and cerebellar surface electrodes. In a prior session with a standard short air-conducted 500-Hz pip, vestibular evoked myogenic potential thresholds were measured and subsequently used to set the acoustic intensity. During the main experiment subjects were asked to synchronise tapping to the pips arranged in the anapaest at two different frequencies, 500 Hz vs 5 kHz, so that only the low-frequency high-intensity condition was a vestibular, as well as an auditory stimulus. We hypothesised that a vestibular effect would manifest in an interaction between the frequency and intensity factors for a range of dependent measures of tapping performance. No clear evidence was found for vestibular effects, but this was likely due to the confounding effects of an independent effect of intensity and the relative weakness of the acoustic vestibular stimulus. However, the data did show novel evidence for two distinct timing processes for the flexion and extension stages of a tap cycle and two distinct timing strategies, which we refer to as ‘staccato’ and ‘legato’, characterised by different profiles of force and extension.

One-Dimensional Model of a Compact DHW Heat Pump with Experimental Validation

The current work presents a computationally cost-effective numerical model that successfully simulates a heat pump water heater (HPWH) under typical working conditions of dwellings. The model’s main components are a stratified tank and the heat-pump unit. Both systems are coupled, since a good prediction of water temperature is needed to accurately predict the heat-pump performance. Ten thermocouples measured the tank wall temperature. Measurements and simulations were performed under challenging conditions of a heavy stratification. The 190 L tank stratification was successfully modeled employing a 1D model, experimentally adjusted by three tapping cycles, with 6 × 22, 6 × 33, and 3 × 33 L consumptions, covering flowrates of 4 and 6 L/min. Water temperature is obtained with an uncertainty of 2.6 °C while the heat-pump was ON. A black box model has been used to obtain the heat-pump performance out of the external and condenser temperatures. For the analyzed days, the COP estimation presents an uncertainty of only 5.1%. Finally, an application example is included. It was used to simulate six tapping cycles of the European standard for heat pump water heaters testing (EN 16147). The results show the possibilities for heat-pump manufacturers of applying this calibrated model to predict the performance of HPWHs under different conditions.

Optimized synthesis condition and mechanism for novel spherical cobalt-free 0.6Li2MnO3·0.4Li[Fe1/3Ni1/3Mn1/3]O2 cathode

The spheroidization of cathode is extremely important for improving tap density and cycle stability. However, the spherical cobalt-free Li-rich and Mn-based cathode of xLi2MnO3·(1-x)LiMO2 (M = Fe, Ni, Mn, LFNMO) have not been successfully synthesized so far. For the first time, a spherical cobalt-free 0.6Li2MnO3·0.4Li [Fe1/3Ni1/3Mn1/3]O2 cathode is synthesized via co-precipitation approach in this work. It exhibits small Brunauer-Emmett-Teller (BET) specific surface area (2.56 m2 g−1) and high tap density (2.11 g cm−3). Meanwhile, an excellent cycle stability is also achieved, which delivers a high reversible capacity of 208 mAh g−1 at C/10 after 100 cycles. Further investigation demonstrates that the optimized sodium carbonate (Na2CO3) precipitant and suitable pH could adjust the solubility product (Ksp) of the precipitate and make the Fe2+, Ni2+ and Mn2+ precipitate simultaneously according to the designed stoichiometric ratio to form the spherical precursor, which is the key to forming the spherical LFNMO. The spherical LFNMO could reduce the side reactions between cathode and electrolyte, form thin cathode electrolyte interphase (CEI) and suppress the electrolyte corrosion to cathode, hence improving electrochemical performance. This work expatiates the synthesis condition and mechanism to prepare spherical LFNMO via co-precipitation, which might greatly advance the designing and development of cathode materials.

Transitions between repetitive tapping and upper limb freezing show impaired movement-related beta band modulation

ObjectiveFreezing phenomena in idiopathic Parkinson’s disease (PD) constitute an important unaddressed therapeutic need. Changes in cortical neurophysiological signatures may precede a single freezing episode and indicate the evolution of abnormal motor network processes. Here, we hypothesize that the movement-related power modulation in the beta-band observed during regular finger tapping, deteriorates in the transition period before upper limb freezing (ULF). MethodsWe analyzed a 36-channel EEG of 13 patients with PD during self-paced repetitive tapping of the right index finger. In offline analysis, we compared the transition period immediately before ULF (‘transition’) with regular tapping regarding movement-related power modulation and interregional phase synchronization. ResultsFrom time-frequency analyses, we observed that the tap cycle related beta-band power modulation over the left sensorimotor area was diminished in the transition period before ULF. Furthermore, increased beta-band power was observed in the transition period compared to regular tapping centered over the left centro-parietal and right frontal areas. Phase synchronization between the left fronto-parietal areas and the left sensorimotor area was elevated during transition compared to regular tapping. ConclusionTogether, these results indicate that diminished beta band power modulation and increased phase synchronization precede ULF. SignificanceWe demonstrate that pathological cortical motor processing is present in the transition phase from regular tapping to an ULF episode.

Thread Quality Control in High-Speed Tapping Cycles

Thread quality control is becoming a widespread necessity in manufacturing to guarantee the geometry of the resulting screws on the workpiece due to the high industrial costs. Besides, the industrial inspection is manual provoking high rates of manufacturing delays. Therefore, the aim of this paper consists of developing a statistical quality control approach acquiring the data (torque signal) coming from the spindle drive for assessing thread quality using different coatings. The system shows a red light when the tap wear is critical before machining in unacceptable screw threads. Therefore, the application could reduce these high industrial costs because it can work self-governance.

Optimization of Metal Tapping Cycle Operation at INALUM

PT Indonesia Asahan Aluminium (Persero) “INALUM” as a Holding State-Owned Mining Industry since November 27, 2017 has passed through long journey until now. As Holding Company, INALUM must maintain and improve competitiveness and the culture of continuous improvement. One of the improvements continuously maintained since joint venture Company between Indonesian Goverment and Japan Consortium is Optimization of Metal Tapping (MT) cycle Operation. The objective of the improvement is to minimize equipment utilization such as Anode Changing Crane (ACC), Ladle and Molten Transport Car (MTC), Minimize man hour, Hidrogen Flouride (HF) gas Emission and improve safety condition. By doing Site observation and direct measurement to understand existing system, analized the data, design new system and take into account of new system to calculate cost benefit analysis and implemented the new system. INALUM has managed to get some benefits from production optimization through motion and time study for lean manufacturing. And the benefits are; optimization of MT cycle operation has successfully reduced ladle utilization for MT until 14 Ladles/day, ACC operation hour 20.5 %, MTC operation hour for ladle transportation 10.5%, Man hour 20.5% for MT work and 10.5 % for ladle transportation, HF Emission gas 20.5 % that caused by MT Operation, balancing operation work and improve safety condition.

Experimental and numerical study of the domestic hot water production with PV panels and a heat pump

This article presents an experimental and modelling work which uses a compact domestic hot water heat pump (DHW-HP) that is simultaneously powered from photovoltaic panels (PV) and from the grid. Results from more than 240 days of experimental works have been used in order to develop and to validate the computer model of the system. The program, implemented in MATLAB, is computationally ‘light’ enough to allow mid-term simulations yet also detailed enough to accurately and coherently portray stratification within thermal storage tanks. Finally, as an example of the model capabilities, it has been used to simulate a domestic hot water tapping cycle from the European Standard EN 16147.

Drainage rate and hearth liquid level estimation in absence of direct measurements in blast furnace

ABSTRACTThe present work deals with the development of a mathematical model to provide the real-time information about important stages of the tapping operation of the iron making blast furnace. In the present work, an attempt is made to derive a generic equation for hot metal and slag drainage rate based upon the empirical approach that makes the liquid level estimation independent of the inter-dependability of the field sensors. This approach is particularly useful where direct measurements are not available. The liquid level model tracks the levels of molten iron and slag inside the hearth based on a continuous analysis of hot metal production and tapped liquid quantities, further certain assumptions are considered such as internal state of the hearth, including its geometry and the stationary state of the coke bed. Because of inaccuracies in the model and in the measurements from the process, an optimal filtering method is applied to provide the reasonable liquid level estimates. The model has been found to provide valuable information about the crucial steps in the tap cycle and is validated with the relevant process parameters with a confidence of ∼95% accuracy.

Flexible nanoenergy harvester using piezo-tribo functional polymer and carbon fibre as electrodes

Micro-energy harvesting has gained immense interest among the research community due to the requirement for self-powering of sensor units in unapproachable environments. Use of simple, low cost, flexible energy harvester aids generation of energy from ambient environments. The present work proposes two devices under test(DUT) with different electrodes namely copper(DUT1) and carbon fibre(DUT2), polymers Polyvinylidene fluoride (PVDF), Polydimethylsiloxane (PDMS) as a functional charge generating materials. The piezoelectric and triboelectric characterisation of polymer films is performed using Dynamic contact mode electrostatic force microscopy(DC-EFM). The proposed DUT1 and DUT2 generates an 8 Vpp and 9 Vpp during human finger tapping. The qualitative and quantitative analysis of DUT1 and DUT2 generated an output voltage of (8.5 V, 12.35 V) (high pressure),(13.5 V, 14.1 V) (285 rpm) respectively. The carbon fibre electrode based flexible device generated an output voltage of 9 V, 10 V and 2.275 V when subjected to biomechanical operations such as finger assisted tapping, press and release as well as bending operations. The device with copper electrode generated 0.32 nJ of energy and power density per unit area of 2.37 pW cm−2 in a single tap cycle. The DUT2 generated thrice the energy and power density than that of DUT1. The DUT2 thus promises to be an efficient, low-cost, flexible energy harvester with PVDF as well as PDMS polymers as a functional layer.

Nanoscale simultaneous chemical and mechanical imaging via peak force infrared microscopy.

Nondestructive chemical and mechanical measurements of materials with ~10-nm spatial resolution together with topography provide rich information on the compositions and organizations of heterogeneous materials and nanoscale objects. However, multimodal nanoscale correlations are difficult to achieve because of the limitation on spatial resolution of optical microscopy and constraints from instrumental complexities. We report a novel noninvasive spectroscopic scanning probe microscopy method-peak force infrared (PFIR) microscopy-that allows chemical imaging, collection of broadband infrared spectra, and mechanical mapping at a spatial resolution of 10 nm. In our technique, chemical absorption information is directly encoded in the withdraw curve of the peak force tapping cycle after illumination with synchronized infrared laser pulses in a simple apparatus. Nanoscale phase separation in block copolymers and inhomogeneity in CH3NH3PbBr3 perovskite crystals are studied with correlative infrared/mechanical nanoimaging. Furthermore, we show that the PFIR method is sensitive to the presence of surface phonon polaritons in boron nitride nanotubes. PFIR microscopy will provide a powerful analytical tool for explorations at the nanoscale across wide disciplines.

The efficiency of the heat pump water heater, during DHW tapping cycle

This paper discusses one of the most effective systems for domestic hot water (DHW) production based on air-source heat pump with an integrated tank. The operating principle of the heat pump is described in detail. Moreover, there is an account of experimental set-up and results of the measurements. In the experimental part, measurements were conducted with the aim of determining the energy parameters and measures of the economic efficiency related to the presented solution. The measurements that were conducted are based on the tapping cycle that is similar to the recommended one in EN-16147 standard. The efficiency of the air source heat pump during the duration of the experiment was 2.43. In the end of paper, authors conducted a simplified ecological analysis in order to determine the influence of operation of air-source heat pump with integrated tank on the environment. Moreover the compression with the different source of energy (gas boiler with closed combustion chamber and boiler fired by the coal) was conducted. The heat pump is the ecological friendly source of the energy.

A Direct-Learning Approach to Acquiring a Bimanual Tapping Skill

ABSTRACTThe theory of direct learning (D. M. Jacobs & C. F. Michaels, 2007) has proven useful in understanding improvement in perception and exploratory action. Here the authors assess its usefulness for understanding the learning of a motor skill, bimanual tapping at a difficult phase relation. Twenty participants attempted to learn to tap with 2 index fingers at 2 Hz with a phase lag of 90° (i.e., with a right-right period of 500 ms and a right-left period of 125 ms). There were 30 trials, each with 50 tapping cycles. Computer-screen feedback informed of errors in both period and phase for each pair of taps. Participants differed dramatically in their success. Learning was assessed by identifying the succession of attractors capturing tapping over the experiment. A few participants’ attractors migrated from antiphase to 90° with an appropriate period; others became attracted to a fixed right-left interval, rather than phase, with or without attraction to period. Changes in attractor loci were explained with mixed success by direct learning, inviting elaboration of the theory. The transition to interval attractors was understood as a change in intention, and was remarkable for its indifference to typical bimanual interactions.