Mechanical Tapping Research Articles

Development of flexible, lead-free electrospun fibers comprising PVDF and NiFe2O4 for harvesting mechanical and stray magnetic fields

This research focuses on crafting highly flexible and efficient mechanical and magneto-mechano-electrical (MME) nanogenerators using electrospun poly (vinylidene fluoride)-nickel ferrite (PVDF-NiFe2O4) composite fibers, tailored for self-powered and wireless sensor networks. Nickel ferrite nanoparticles, averaging 40 nm in crystallite size, were synthesized through the autocombustion method and integrated as fillers within the PVDF matrix. Analysis via XRD and FTIR confirmed a greater presence of the ferroelectric β-phase in the PVDF electrospun fibers, accentuated by the incorporation of NiFe2O4. Notably, the mat containing 5 wt% of NiFe2O4 boasted an estimated 86 % β-phase. SEM micrographs depicted the formation of uniform bead-free fiber with a diameter of 900 nm. VSM analysis verified the ferrimagnetic properties of the composite fiber mats, registering a maximum saturation magnetization of 4.6 emu/cm3. Under mechanical tapping, the nanogenerator yielded an output voltage of 16.5 V and a power of 0.8 μW. The study also compared the performance of two MME nanogenerator geometries (rectangular and truncated) under an AC magnetic field of 10 Oe. Remarkably, the MME nanogenerator with a truncated geometry exhibited superior performance, generating 6.2 V, a 50 % increase over the rectangular counterpart.

An Optimization Study on a Novel Mechanical Rubber Tree Tapping Mechanism and Technology

All-natural rubber is harvested from rubber trees (Hevea brasiliensis Muell. Arg.) by traditional tapping knives, so rubber tapping still heavily relies on labor. Therefore, this study explored a novel, hand-held mechanical rubber tapping machine for rubber tree harvesting. In this study, a mechanical tapping cutter with a vertical blade and adjustable guide was first described. The response surface method was applied to evaluate factors affecting the tapping effect. The experimental values were in close agreement with the predicted value. Machine-tapped latex was comparable in quality to hand-tapped latex. Based on the single-factor results, the response surface method (RSM) and the center combined rotation design (CCRD) optimization method were adopted to explore the influence of three factors influencing vertical blade height (A), cutting force (B), and spiral angle (C) on the tapping effect. Regarding the cutting rate of the old rubber line (Y1), cutting time (Y2), latex flow rate (Y3), and average cutting current (Y4) as evaluation indexes of the tapping effect, an optimization scheme was determined. The quadratic model fits for all the responses. The test results showed that the main factors affecting Y1, Y2, Y3, and Y4 were A and B, B, A and C, and B, respectively. Under optimal conditions, the influencing factors of A, B, and C were 10.24 mm, 51.67 N, and 24.77°, respectively, when the evaluation index values of Y1, Y2, Y3, and Y4 were 98%, 8.65 mL/5 min, 9.00 s, and 1.16 A. The range of the relative error between the experimental and predicted results was from −11.11% to 11.11%. According to the optimized treatment scheme, a comparison test was designed between mechanical and manual rubber tapping tools. To verify the availability and effect of the mechanical tapping method preliminarily, the important rubber tapping evaluation indexes included bark thickness, bark excision, latex flow time, cutting time, ash content, and cutting depth, which were selected to serve as a comparison test. There was no significant difference between hand and mechanical methods, except ash content (p < 0.05) and cutting time (p < 0.01). The mechanical tapping machine proposed in this study is meaningful to improve cutting efficiency, practicality, and operability. Furthermore, it provides crucial theoretical references for the development of intelligent tapping machines.

Controllable Friction on Graphene via Adjustable Interfacial Contact Quality.

Despite the numerous unique properties revealed through tribology research on graphene, the development of applications that utilize its rich tribological properties remains a long-sought goal. In this article, a novel approach for reversible patterning of graphene's frictional properties using out-of-plane mechanical tapping is presented. The friction force between the atomic force microscopy (AFM) tip and the graphene film is increased by up to a factor of two, which can be attributed to variations in the interfacial binding strength between the graphene and substrate through the tapping process. The reversible and repeatable frictional properties of graphene make it a promising material for information storage applications with a high storage capacity of ≈1600 GB inch-2 , allowing for direct writing and erasing of information, akin to a blackboard. These findings highlight the potential for friction tuning in lamellar materials and emphasize the significance of understanding nanoscale friction on graphene surfaces.

Edge-Site-Enriched Ti3C2Tx MXene/MoS2 Nanosheet Heterostructures for Self-Powered Breath and Environmental Monitoring

The architecture of an ammonia (NH3) monitoring system that serves as a versatile tool for real-time breath sampling and environmental gas sensing is proposed herein. By means of first-principles density functional theory (DFT) simulations, an edge-site-enriched MXene/MoS2 nanosheet heterostructure is systematically investigated and used both as a sensing material and an active layer of a hybrid tribo-/piezonanogenerator (H-TPNG). This allows combining the potential of gas sensing and energy harvesting into a single device, with benefits of self-powered monitoring of NH3. The high selectivity, reversibility, and sensitivity (47%@10 ppm) of the prepared sensor to target NH3 gas are revealed, resulting from the increased adsorption sites and improved charge transfer at the edge sites observed from DFT studies. On the other hand, the mechanical tapping and bending motions of the H-TPNG effectively stimulate the instantaneous triboelectric and piezoelectric power densities of 1604.44 and 15.62 mW/cm2, respectively. Additionally, the nanofibrous morphology of the H-TPNG introduced by the electrospinning technique provides great flexibility and conformability to the device for large-area integration of body parts. Finally, a self-powered NH3 monitoring system is assembled which demonstrates the autonomous operation of a sensor for breath analysis and environmental monitoring and could pave the way for the advancement of wearable monitors for healthcare applications.

Experimental Test of the Edwards Volume Ensemble for Tapped Granular Packings.

Using x-ray tomography, we experimentally investigate granular packings subject to mechanical tapping for three types of beads with different friction coefficients. We validate the Edwards volume ensemble in these three-dimensional granular systems and establish a granular version of thermodynamic zeroth law. Within the Edwards framework, we also explicitly clarify how friction influences granular statistical mechanics by modifying the density of states, which allows us to determine the entropy as a function of packing fraction and friction. Additionally, we obtain a granular jamming phase diagram based on geometric coordination number and packing fraction.

The Theoretical Research on Technical Advance and Innovation Integration of Tapping Machinery

Mechanical tapping becomes an important issue to be resolved in urgent need at present, which is one hot problems of the technology research at present. This paper introduces the progress and frontier of tapping technology, and analyses and summarizes the research on semi-automatic tapping machinery and automatic tapping machinery. The development of mechanical tapping is still at the exploration stage, and the fundamental theory research is insufficient. The technology needs to move from prototype stage to more mainstream use for quite some time. The type 4GXJ-I of cordless brushless tapping knife designed by our team and automatic tapping machinery designed by Zhenkun Xu in China, have presented obvious advantage in the study of mechanical tapping machine. Application of mechanical tapping machines has a very important significance to sustainable development of natural rubber industrial economy.

Y3+ doped 0.64PMN-0.36PT ceramic for energy scavenging applications: Excellent piezo-/ferro-response with the investigations of true-remanent polarization and resistive leakage

In this work, the detailed ferroelectric properties of pure and yttrium doped 0.64 Pb(Mg1/3Nb2/3)O3-0.36PbTiO3 (Y-doped PMN-PT) ceramics including determination of true remanent polarization and study of resistive leakage were investigated. In dielectric study, the transition temperature (Tm) for the pure and Y-doped ceramic was found to be 205 °C and 165 °C, respectively. Displacement vs. Voltage (D-V) butterfly loops were traced from which a high value of the piezoelectric coefficient for Y-doped PMN-PT (d33 = 604 pm/V) was revealed which was fairly greater than the observed value for pure PMN-PT (d33 = 547 pm/V). The Y-doped PMN-PT ceramic displayed excellent saturated ferroelectric hysteresis loops with higher values of coercive field (Ec), spontaneous (Ps) and remanent (Pr) polarizations, and pyroelectric coefficient (p) compared to the pure PMN-PT ceramic. Also, the Y-doped PMN-PT ceramic displayed good fatigue resistant characteristic indicating its high ferroelectric quality. The relative values of true remanent polarization i.e. Ptr/Pr (in %) were found to be ∼82.86% and 89.60% for pure and Y-doped PMN-PT, respectively using the “Remanent Hysteresis” Task. Also, the resistive-leakage characteristic of both pure and doped ceramics was analyzed using Time-dependent compensated (TDC) hysteresis task. Finally, both pure and Y-doped PMN-PT ceramics have been used for building piezoelectric energy harvesting devices (PEHDs). The Y-doped PMN-PT ceramic based PEHD showed enhanced performance by generating an output voltage around 60 V under periodic mechanical tapping (∼2.0 kgf @ 5 hz) and thus finds application in powering various self-powered devices.

FlashPack: Fast and Simple Preparation of Ultrahigh-performance Capillary Columns for LC-MS*

Capillary ultrahigh-pressure liquid chromatography (cUHPLC) is essential for in-depth characterization of complex biomolecule mixtures by LC-MS. We developed a simple and fast method called FlashPack for custom packing of capillary columns of 50-100 cm length with sub- 2 μm sorbent particles. FlashPack uses high sorbent concentrations of 500-1,000 mg/ml for packing at relatively low pressure of 100 bar. Column blocking by sorbent aggregation is avoided during the packing by gentle mechanical tapping of the capillary proximal end by a slowly rotating magnet bar. Utilizing a standard 100-bar pressure bomb, Flashpack allows for production of 15-25 cm cUHPLC columns within a few minutes and of 50 cm cUHPLC columns in less than an hour. Columns exhibit excellent reproducibility of back-pressure, retention time, and resolution (CV 8.7%). FlashPack cUHPLC columns are inexpensive, robust and deliver performance comparable to commercially available cUHPLC columns. The FlashPack method is versatile and enables production of cUHPLC columns using a variety of sorbent materials.

Transparent-flexible-multimodal triboelectric nanogenerators for mechanical energy harvesting and self-powered sensor applications

Triboelectric nanogenerators (TENGs) harvest and convert mechanical energy to electrical energy. TENGs that are transparent and flexible can be applied to various (opto-)electronic devices supporting finger- or pen-based touchscreen inputs. This paper presents a transparent, flexible TENG that harvests mechanical tapping energy (typically discarded) by simple placement on touchscreen devices. The developed TENG consists of flexible and transparent conducting electrodes (FTCE) with high transmittance (> 93%) and low sheet resistance (18.5 Ω/sq), and transparent 3D-hierarchical polydimethylsiloxane (PDMS) with porous pyramid-patterns. In this study, the developed TENG directly powered eight light-emitting diodes (LEDs) by harvesting the mechanical energy produced by tapping with a touch pen while playing a smartphone game. We also used the transparent TENG as a transparent single-electrode-based, self-powered raindrop detection sensor on a window for a smart home. Our results indicate that the proposed TENG can be used not only as an effective mechanical energy harvester for transparent, flexible, and next-generation optoelectronics devices but also as a self-powered sensor for future Internet-of-Things applications.

Non-standard uses of the mechanical tapping machine in field measurements

The mechanical tapping machine creates a continuous series of floor impacts which generate a steady-state sound field when measured indoors. Because each individual hammer has the same weight and free-falls from the same distance, the machine creates a calibrated and steady impulsive force into the floor structure. This presentation will illustrate potential future test methods for assessing sound transmission in buildings with examples to evaluate structure-borne sound transmission into structurally isolated anechoic and reverberation rooms.

The Hillary Climber trumps manual testing: an automatic system for studying Drosophila climbing

Climbing or negative geotaxis is an innate behavior of the fruit fly Drosophila melanogaster. There has been considerable interest in using this simple behavior to gain insights into the changes in brain function associated with aging, influence of drugs, mutated genes, and human neurological disorders. At present, most climbing tests are conducted manually and there is a lack of a simple and automatic device for repeatable and quantitative analysis of fly climbing behavior. Here we present an automatic fly climbing system, named the Hillary Climber (after Sir Edmund Hillary), that can replace the human manual tapping of vials with a mechanical tapping mechanism to provide more consistent force and reduce variability between the users and trials. Following tapping the HC records fly climbing, tracks the fly climbing path, and analyzes the velocity of individual flies and the percentage of successful climbers. The system is relatively simple to build, easy to operate, and efficient and reliable for climbing tests.

American Society of Testing Materials draft standard for rating in-room floor impact noise

In 2010 an ASTM subcommittee was formed to assess the possibility of rating the noisiness of different floor surfaces from impacts such as footfalls and dropped objects. Since that time the subcommittee has been meeting biannually to discuss potential impact noise sources and measurement techniques that could be used in a future standard. Different impact sources were evaluated including footfalls with different shoe types, golf balls, and the standard mechanical tapping machine. Both field and laboratory measurements were considered. This paper presents some of the preliminary test results that were obtained and the current status of the proposed laboratory standard.

Timbre maps to characterize the sound quality of the Japanese koto

The Japanese koto and related zithers in East Asia are known for their distinctive sound quality (timbre), but the precise origins of the characteristics remain elusive. In an attempt to extend the knowledge of these characteristics, a finite element model of the Japanese koto(13 string plucked zither) was constructed using Comsol Multiphysics 5.1 based on a koto of known provenance and parameters. A series of experiments to identify the acoustical properties of the instrument were compared against results of the model. The results were then collated into a series of timbre maps to establish patterns of responses. This included overlaying eigenfrequencies, individual peaks from the spectra of the thirteen strings for the standard (hirajōshi) tuning, hidden peaks identified by the fourth derivative frequency scans and spectra from mechanical tapping of the reference instrument. The study shows that the anisotropy of the paulownia wood of the koto plays an important role in the vibration modes and frequency response spectrum. The timbre maps then identifies characteristics of the non harmonic responses that contribute to the koto’s distinctive sound and provide a template for the study of sound quality associated with culturally specific timbral preferences for East Asian zithers.

Newly Identified Characteristic of Taste Avoidance Conditioning with High Voltage as an Unconditional Stimulus in <i>Lymnaea Stagnalis</i>

Based on the newly established taste avoidance conditioning paradigm, Lymnaea can learn the temporal sequence of sucrose application and subsequent applied high voltage with small current resulting in significant suppression of feeding response to sucrose. The most efficient condition to acquire the long-term memory (LTM) is obtained by 15 paired presentations of a conditional stimulus (CS) and an unconditional stimulus (US). This repetition number for LTM acquisition is different among the taste avoidance conditioning employed as US, such as KCl, mechanical tapping and electrical high voltage, however the behavioral modification is thought to activate the same neuronal circuit via RPeD11 which is the inter neuron to control the whole-body withdrawal response. All of these USs are thought to be recognized as a noxious stimulus sensing at RPeD11.

Measurement of the tap density of metal powders

The paper deals with one of the technological properties of metal powders, such as tap density. The objective is to analyze the state standard in force for determining the density of metal powders after tapping, taking into account operational experience in the field of powder metallurgy. It is established that the methods identified in the standard for determining the density of metal powders have contradictions and discrepancies. A simple and reliable device is proposed and manufactured for mechanical tapping of powders.

Potential Damage to Bone–Implant Interface When Measuring Initial Implant Stability

An electronically controlled mechanical tapping device (MTD) to measure implant stability has been studied extensively for its ability to measure initial stability at the time of surgical placement and predict an implant's survival prognosis, with few reported complications. Initial stability data, measured repeatedly with a resonance frequency analysis device and the MTD, for seven of 28 implants placed in jawbones of four fresh human cadavers and the histologic images of bone-implant interfaces are presented as evidence for potential damage to the bone-implant interface using these techniques. A progressive increase in mobility from stable (-1) to less stable (4) and eventually to visibly mobile (999) was observed after three measurements with the MTD. Corresponding histologic images revealed that the buccal threads in the coronal half of the implants were displaced lingually and apically from the bony indentations that were created during insertion of the self-threading implants, subsequent to repeated MTD measurements in the buccal and axial directions. The histologic images and changes in MTD values indicated that repeated MTD measurements at the time of implant placement surgery may damage the bone-implant interface, and a stable or borderline implant may become mobile after repeated MTD measurements. Histologic images showed potential damage to the bone-implant interface during repeated initial implant-stability measurements using the MTD. Initial implant-stability measurements using the MTD should be performed with caution, and they may be contraindicated for implants placed in low-quality bone.

Initial stability measurement of dental implants placed in different anatomical regions of fresh human cadaver jawbone

Initial implant stability has been used as an indicator for future osseointegration and whether an immediate/early loading protocol should be applied. However, differences in initial stability in relation to anatomical regions of jawbone have not been studied extensively because of the risks involved with stability measurements. The purpose of this study was to determine whether initial implant stability varies with anatomical regions of the jawbone. Four pairs of edentulous maxillae and mandibles were retrieved from fresh human cadavers. Six implants (Biomet 3i) per pair were placed in different anatomical regions (maxillary anterior, right and left maxillary posterior, mandibular anterior, right and left mandibular posterior). Immediately after implant placement, initial implant stability was measured with a custom-made resonance frequency analyzer, a commercial resonance frequency analysis device (Osstell), and a mechanical tapping device (Periotest). All implant surgeries and initial stability measurements were performed within 72 hours of death to simulate a clinical setting. Repeated measures ANOVA (alpha=.05) and univariate correlation analyses were used to analyze the data. Mandibular implants had significantly higher initial stability than maxillary implants. Posterior maxillary implants were least stable. Stability was less buccolingually than mesiodistally. The measurements from 3 stability measuring devices were strongly associated with each other. Initial implant stability varied among anatomical regions of jawbone. Rank of Periotest value and implant stability quotient (Osstell) had the highest correlation (r=-0.852).

Hierarchy of Habituation Induced by Mechanical Stimuli in Caenorhabditis elegans

C. elegans becomes habituated to repetitive mechanical stimuli. We compared the habituated states induced by three types of mechanical stimuli: touch on the head (head-touch), touch on the anterior body (body-touch), and mechanical tapping of the Petri dish, all of which evoke backward movement. The habituation patterns were similar, but differed in retention period and/or the rate of recovery. We found a hierarchy between the habituated states induced by the three types of mechanical stimuli in the decreasing order of head-touch, body-touch, and tap stimulus. Evidence is presented that the hierarchy is brought out by the magnitude of stimuli rather than by independent neural pathways.

Statistical mechanics of vibration-induced compaction of powders

We propose a theory which describes the density relaxation of loosely packed, cohesionless granular material under mechanical tapping. Using the compactivity concept we develope a formalism of statistical mechanics which allows us to calculate the density of a powder as a function of time and compactivity. A simple fluctuation-dissipation relation which relates compactivity to the amplitude and frequency of a tapping is proposed. Experimental data of E.R.Nowak et al. [{\it Powder Technology} 94, 79 (1997) ] show how density of initially deposited in a fluffy state powder evolves under carefully controlled tapping towards a random close packing (RCP) density. Ramping the vibration amplitude repeatedly up and back down again reveals the existence of reversible and irreversible branches in the response. In the framework of our approach the reversible branch (along which the RCP density is obtained) corresponds to the steady state solution of the Fokker-Planck equation whereas the irreversible one is represented by a superposition of "excited states" eigenfunctions. These two regimes of response are analyzed theoretically and a qualitative explanation of the hysteresis curve is offered.

A muscle fatigue index based on the relationship between preceding background activity and myotatic reflex response (MRR).

A new index of muscular fatigue was developed using the myotatic reflex response (MRR). The MRR of masseter muscles is evoked by periodical mechanical chin tapping during clenching. The MRR waveform is composed of somewhat synchronized action potentials of muscle fibers. We estimate the change of the MRR waveform due to fatigue using the instantaneous frequency pattern (IFP) with the Hilbert transform. As a result, the features of IFP were different from the monotonic changes that have been observed by the conventional fatigue indices. That is, a plateau IFP was observed ahead of considerable fatigue, whereas the IFP showed a monopeak pattern during other phase of an exercise. Also, the relationship between the preceding background mean power frequency and the instantaneous frequency around the first part of the MRR waveform was nonlinear during the whole process of fatigue. These features may allow us to estimate the degree of fatigue at each time instant. Although the details have not yet been solved, by using the computer simulations one of them seemed to be the alteration of the dominant frequency components. The dominant frequency components may be related to the active muscle fiber types.