Vertical Tapping Research Articles

Automated Classification of Egg Freshness Using Acoustic Signals and Convolutional Neural Networks

Abstract The acoustic response of eggs has not been fully optimized for quality detection purposes. This research investigates the utilization of acoustic response as input features for classifying fresh and rotten eggs using Convolutional Neural Networks (CNN). Acoustic measurements were conducted using an experimental setup involving a striking rod, microphone, and microcontroller to capture acoustic responses from eggs struck vertically and horizontally. Features such as energy, entropy, zero crossing rate, spectral centroid, and Mel Frequency Cepstral Coefficients (MFCC) were extracted from the recorded acoustic signals. The study utilized a sample set of 200 intact chicken eggs without cracks, equally split between fresh and rotten eggs. Principal Component Analysis (PCA) revealed significant differences in acoustic responses between fresh and rotten eggs, with clear separation observed in horizontal measurements. Three primary classification models—Convolutional Neural Network (CNN), Deep Neural Network (DNN), and Support Vector Machines (SVM)—were evaluated for this classification task. In vertical tapping, CNN and DNN demonstrated stable performance with approximately 85% accuracy, while SVM slightly trailed with around 80% accuracy. However, in horizontal tapping, all three models achieved perfect classification with accuracy, precision, recall, and F1-score reaching 100%. This study demonstrates the effective use of acoustic response as input for Deep Learning models to distinguish between fresh and rotten eggs. The findings highlight the potential application of this technology in the food industry to ensure product quality before consumption, with significant implications for developing reliable automated solutions. Future research could expand validation using larger datasets and optimize sensor usage and data processing techniques to enhance detection consistency and reliability.

Direct Observation of Contact Electrification Effects at Nanoscale Using Scanning Probe Microscopy

AbstractIn the last decade, contact electrification has gained attention for its potential in energy harvesting, addressing fundamental physics. Scanning probe microscopy (SPM) has evolved as a powerful platform, enabling the in situ characterization/manipulation of a sample's tribological/electrical properties at nanoscale. However, although both the sliding and tapping modes are available in the energy harvesting, the lateral sliding using contact mode SPM has predominantly been employed in triboelectric study. In this work, contact electrification on polydimethylsiloxane is investigated, using peak force tapping atomic force microscopy (PF‐AFM). As PF‐AFM quasi‐discretely offers vertical tapping motions of the probe with a regulated force amplitude, resembling a vertical‐type triboelectric nanogenerator, while minimizing lateral forces. The subsequent surface potential measurements reveal that the generated tribocharge is influenced by both the effective work function difference and energy dissipation at the interface. Furthermore, the accumulation of transferred charges is explored by measuring tip‐sample current during the PF‐AFM operation, showing the comparable results with the surface potential measurement. The results can be attributed to the contact potential difference assisted by the energy dissipation at the interface. This study offers an advanced opportunity to understand and study charge generation behavior based on surface properties without damaging the sample.

Segregation of sand-rubber chips mixtures subject to vertical tapping under confinement

Mixtures of rigid sand particles and soft rubber particles (rubber chips) are prepared and submitted to vertical taps in a confined cell to investigate their propensity to segregate. The mixture evolution is characterized by means of image analysis of slices obtained by a gelification technique. We show that, in case of equally sized particles, the rubber particles tend to migrate towards the bottom of the system. Yet, the segregation is not complete and is reduced when the rubber fraction is increased. Also it competes with the size induced segregation if rubber chips are larger than sand particles. A tendency to form horizontal clusters is clearly observed and increases with the number of taps. This horizontal segregation is reduced if the rubber fraction is smaller and is weakly influenced by grain size difference. Both the vertical segregation and the formation of horizontal heterogeneities are prevented by adding a small amount of water.

Effects of aerodynamic pressure tap layout and resolution on estimated response of high-rise structures: A case study

This study examines the influence of pressure tap density and layout on estimated wind effects of a 47-story steel building for which the Database-Assisted Design procedure is used to calculate the base shears, base overturning moments, member Demand-to-Capacity Indexes (DCIs), inter-story drift ratios, and floor accelerations. From an original tap layout (20 rows by 5 columns, total 100 taps per façade), a total 16 tap layout cases were created varying vertical and horizontal tap densities. The influence of the tap density on the estimated wind effects of interest was then investigated. In most cases the calculated structural response is significantly more influenced by the horizontal than by the vertical tap density. The influence of the tap density was found to be strongest on the estimated base torsion, followed by the member DCIs, the base shears, and the base overturning moments. The acceptable pressure tap density depends on the structural response of interest. The results show that the current practice of considering global quantities like the overturning moment and/or the base shear as indicators of the adequacy of tap resolution for structural design can be misleading.

Miura-origami-inspired electret/triboelectric power generator for wearable energy harvesting with water-proof capability

One of the critical issues for electret/triboelectric devices is the poor charge viability and stability in humid environments. Herein, we propose a new origami-inspired “W-tube”-shaped triboelectric nanogenerator (W-TENG) with two thin-film electrets folded based on Miura-origami. The Miura-origami fold is capable of transforming flat materials with large surface areas into reduced and compressed complex 3D structures with parallelogram tessellations. The triboelectric power generation components can thus be hermetically sealed inside the “W-tube” to avoid contact with the external humid environment. Furthermore, the elastic nature of the Miura-origami fold endows the proposed W-TENG device with excellent deformability, flexibility, and stretchability. Therefore, it is capable of harvesting kinetic energy from various directions and forms of movement, including horizontal pressing, vertical tapping, and lateral bending. The compact, light weight, and self-rebounding properties of the origami structure also make it convenient for integration into wearable devices. Various parameters of the W-TENG are intensively investigated, including the number of power generation units, original height of the device, acceleration magnitude, excitation direction, and water-proof capability. Triggered by hand tapping impulse excitation in the horizontal and vertical directions, the instantaneous open-circuit voltages can reach 791 V and 116 V with remarkable optimum powers of 691 μW at 50 MΩ and 220 μW at 35 MΩ, respectively. The outcomes of this work demonstrate the fusion of the ancient art of origami, material science, and energy conversion techniques to realize flexible, multifunctional, and water-proof TENG devices.

Self-powered wearable touchpad composed of all commercial fabrics utilizing a crossline array of triboelectric generators

In the internet of things (IoT) era, electronic textile (E-textile), which combines diverse functional parts on a fabric substrate, has attracted much attention. Among the various components for E-textile, the human-machine interface device is one of the most important. Here, a wearable fabric touchpad based on a triboelectric generator (TEG) is demonstrated. It is created only with inexpensive commercialized fabrics. Long string-shaped fabric TEGs act as the rows and columns of a crossline array, and each cross-point of a unit cell at each row and column constructs a unit pixel. The proposed touchpad accurately traces basic motions such as the vertical tapping and lateral dragging of a polytetrafluoroethylene (PTFE) stylus and generates corresponding output signals. Based on this capability, the proposed touchpad can be utilized for the handwriting of digits and for their recognition as well. Digits from 0 to 9 written on the touchpad are successfully classified by a pre-trained neural network with very high accuracy of 98%. This implies that the proposed wearable touchpad has immediate practicality. Considering its cost-effectiveness, compatibility with the textile industry, and its accurate operation, the proposed touchpad is a strong candidate for use in interface devices in the future E-textile industry.

Effect of combined deficit irrigation and grass competition at plantation on peach tree root distribution

Agroforestry systems success is predicated on the assumption of root spatial separation between the tree and the crop species. Such a feature, where tree roots prospect subsoil horizons whereas intercrop roots prospect top soil horizon is thought to eventually happen as the system ages and trees get older. However, since roots are very plastic, we can hypothesise that it is possible to shape the tree root system when trees are young, i.e. after plantation. In this experiment, we tested the hypothesis that combining a moderate water deficit to change the carbon allocation pattern in favour of root over shoot growth combined with the top soil competition brought about by the intercrop will force tree roots to grow deeper, thus leading to the vertical separation of the trees and the intercrop root systems. To test this hypothesis, a peach tree orchard was established in 2014 with three water regime treatments: (i) a fully irrigated control without intercrop (C), (ii) a moderate water deficit treatment without intercrop (RDI) and (iii) a moderate water deficit treatment intercropped with a grass + legume mixture (RDI + G). Roots were manually excavated at the end of the first and the second growing seasons and root length and biomass per soil horizon and distance to the tree trunk were measured. The juvenile tree root system in all treatments was mainly plagiotropic, reaching 1.5 m from the tree trunk (middle of the inter row) horizontally as opposed to 0.7 m vertically, without difference between treatments. The combination of water deficit and intercrop competition reduced tree root biomass fourfold in 2014 and by 3 in 2015. Tree roots in RDI + G were also excluded from the topsoil horizon (0–10 cm) due to grass + legume competition, but because of the strong reduction in their total biomass, they did not grow in deeper soil horizons than the control tree roots (C). Secondary vertical tap roots were only starting to grow by the end of the second year, suggesting that root growth at depth could not take place the year after plantation especially in grafted scions.

Towards minimal models for realistic granular materials: Tomographic analysis of bidispersed assemblies of ellipsoids

In this paper, we report experimental results on granular compaction in a model system made of mono- and bidisperse ellipsoidal packings as well as sand packings with grain size polydispersity. The packings are subject to vertical tapping of varying duration (number of taps) and their internal three-dimensional structure is obtained using x-ray computed tomography. Particles positions and orientations are reconstructed and the global packing densities are computed. The analysis of the vertical and horizontal local packing fraction profiles reveal a homogeneous densification in the ellipsoidal packings, however, sand packings exhibit radial density gradient, possibly linked to the onset of convection.

Mobile application of finger tapping task assessment for early diagnosis of Parkinson's disease

A mobile application named HLTapper was designed for Android mobile phones to collect and assess real-time alternating finger tapping movement data such as mean tapping speeds, temporal variations of tapping intervals, horizontal tapping variances, and vertical tapping variances, from built-in sensors while a subject performs the finger tapping movement task according to directions given through the application interface. The results of a controlled experiment (40 subjects including nine subjects with Parkinson disease, 11 healthy age-matched subjects, and 20 healthy young subjects) and a discriminant analysis revealed sensitivity of 85.71% and specificity of 91.42%, on an average, which suggests that HLTapper would be useful for early diagnosis and personalised treatment plan adjustments of patients with Parkinson disease.

Sensitivity of Granular Force Chain Orientation to Disorder-Induced Metastable Relaxation.

A two-dimensional system of photoelastic disks subject to vertical tapping against gravity was experimentally monitored from ordered to disordered configurations by varying bidispersity. The packing fraction ϕ, coordination number Z, and an appropriately defined force-chain orientational order parameter S all exhibit as similar sharp transition with a small increase in disorder. A measurable change in S, but not ϕ and Z, was detected under tapping. We find disorder-induced metastability does not show configurational relaxation, but can be detected via force-chain reorientations.

Derivation of stretched exponential tap density equations of granular powders.

The tap density of granular powders was found to be better fitted with the stretched exponential law. In our previous work, the stretched exponential tap density equations were derived with the rate process theory and free volume concept, under the assumption that the particle packing rate during the tapping process obeys the stretched Arrhenius equation, which, however, has an empirical origin. In this article, the above assumption is eliminated and attempts are made to obtain the stretched exponential tap density equations from very fundamental bases. In a vertical tapping process, the probability of particles attaining certain energy states is assumed to obey the Boltzmann distribution and particles traveling from one site to another are assumed to follow a very common memoryless random exponential law. The stretched exponential tap density equations are thus derived and all parameters acquire clear physical meanings. The most important parameter, the stretched exponential, is demonstrated to correlate with the interparticle forces: a small value may indicate a strong adhesive or cohesive interaction. Therefore, the stretched exponential could be a better indicator for powder flowability correlated with particle interactions as well.

Analysis, simulation and visualization of 1D tapping via reduced dynamical models

A low-dimensional center-of-mass dynamical model is devised as a simplified means of approximately predicting some important aspects of the motion of a vertical column comprised of a large number of particles subjected to gravity and periodic vertical tapping. This model is investigated first as a continuous dynamical system using analytical, simulation and visualization techniques. Then, by employing an approach analogous to that used to approximate the dynamics of a bouncing ball on an oscillating flat plate, it is modeled as a discrete dynamical system and analyzed to determine bifurcations and transitions to chaotic motion along with other properties. The predictions of the analysis are then compared–primarily qualitatively–with visualization and simulation results of the reduced continuous model, and ultimately with simulations of the complete system dynamics.

Compaction and arching in tapped pentagon deposits

We simulate the process of compaction under vertical tapping for a two-dimensional system of particles deposited in a rectangular box. The particles consist in regular pentagons and our main objective is to analyze the novel behavior recently found for the packing fraction as a function of the tapping strength applied to the system (Vidales et al. in Phys Rev E 77:051305, 2008). We will relate the behavior of the number and type of arches, mean coordination number and number and type of contacts to the peculiar packing density increase found for increasing tapping strength. Finally, we present results of an annealed tapping on our packings to compare the results to the constant tapping protocol. All our results are compared with the analogous simulations carried out on disks.

Low Loss Vertical Optical Path Conversion Using 45° Mirror for Coupling between Optical Waveguide Devices and Planar Devices

To realize low loss optical interconnects between optical waveguide devices and two dimensional array-type devices, we investigated a novel 45° mirror device buried by index matching epoxy resin and coated with an anti-reflection layer. A groove with an isosceles right triangle cross section was formed using a dicing saw so as to cut into the single-mode optical waveguide, and aluminum thin film was obliquely deposited on the 45° side wall of the groove to increase the reflectance. The groove was filled with a spin-coating of UV-curable epoxy resin to planarize the top surface, and low index polymer (Teflon) was formed on the top surface as the anti-reflection layer. The optimum depth of the groove for reducing shadowing of the deflected beam was analyzed. As a result the insertion loss of the 45° mirror was reduced 1.3 dB compared to the insertion loss of straight waveguide. In addition, a novel optical tap device is proposed and demonstrated using a similar fabrication process to that of the 45° mirror device. The isosceles right triangle-shaped groove was formed on the upper cladding layer so as to almost touch the core layer. After filling it in and finishing it with the epoxy resin and AR coating used in the 45° mirror device, the loss of the through port was reduced 0.5 dB compared to the insertion loss of straight waveguide and -14 dB (4.0%) of the optical power was transmitted to the tap port. Lastly as a model of the coupling between waveguide devices and two-dimensional arrayed devices such as vertical cavity surface emitting lasers (VCSEL's), the vertical port of the 45° mirror device was connected to a single mode fiber with a very small mode field diameter (3.6 µm). This configuration transmitted -11.8 dB (6.6%) of the input power from the input port to the vertical tap port and vice versa.

Pentagon deposits unpack under gentle tapping

We present results from simulations of regular pentagons arranged in a rectangular box. The particles are subjected to vertical tapping. We study the packing fraction, number of contacts, and arch size distribution as a function of the tapping amplitude. Compared with disks, pentagons show peculiar features. As a general rule, pentagons tend to form fewer arches than do disks. Nevertheless, as the tapping amplitude is decreased, the typical size of the pentagon arches grows significantly. As a consequence, a pentagon packing reduces its packing fraction when tapped gently, in contrast with the behavior found in rounded particle deposits.

Granular packs under vertical tapping: Structure evolution, grain motion, and dynamical heterogeneities

The compaction dynamics of a granular media subject to a sequence of vertical taps made of fluid pulses is investigated via molecular dynamics simulations. Our study focuses on three different levels: macroscopic (volume fraction), mesoscopic (Voronoï volumes, force distributions), and microscopic (grain displacements). We show that the compaction process has many characteristics which are reminiscent of the slow dynamics of glass forming systems, as previously suggested. For instance, the mean volume fraction slowly increases in time and approaches a stationary value following a stretched exponential law, and the associated compaction time diverges as the tapping intensity decreases. The study of microscopic quantities also put in evidence the existence of analogies with the dynamics of glass formers, as the existence of dynamical heterogeneities and spatially correlated motion of grains; however, it also shows that there are important qualitative differences, as, for instance, in the role of the cage effect. Correlations between geometry and dynamics of the system at the grain level are put in evidence by comparing a particle Voronoï volume and its displacement in a single tap.

Simulation study of granular compaction dynamics under vertical tapping

We study, by numerical simulation, the compaction dynamics of frictional hard disks in two dimensions, subjected to vertical shaking. Shaking is modeled by a series of vertical expansion of the disk packing, followed by dynamical recompression of the assembly under the action of gravity. The second phase of the shake cycle is based on an efficient event-driven molecular-dynamics algorithm. We analyze the compaction dynamics for various values of friction coefficient and coefficient of normal restitution. We find that the time evolution of the density is described by rho(t)=rho{infinity}-DeltarhoE{alpha}[-(ttau){alpha}], where E{alpha} denotes the Mittag-Leffler function of order 0<alpha<1 . The parameter tau is found to decay with tapping intensity Gamma according to a power law tau proportional, variantGamma{-gamma}, where parameter gamma is almost independent on the material properties of grains. Also, an expression for the grain mobility during the compaction process has been obtained. We characterize the local organization of disks in terms of contact connectivity and distribution of the Delaunay "free" volumes. Our analysis at microscopic scale provides evidence that compaction is mainly due to a decrease of the number of the largest pores. An interpretation of the memory effects observed for a discontinuous shift in tapping intensity Gamma is provided by the analysis of the time evolution of connectivity numbers and volume distribution of pores.

Granular Species Segregation under Vertical Tapping: Effects of Size, Density, Friction, and Shaking Amplitude

We present extensive molecular dynamics simulations on species segregation in a granular mixture subject to vertical taps. We discuss how grain properties, e.g., size, density, friction, as well as shaking properties, e.g., amplitude and frequency, affect such a phenomenon. Both the Brazil nut effect (larger particles on the top, BN) and the reverse Brazil nut effect (larger particles on the bottom, RBN) are found and we derive the system comprehensive "segregation diagram" and the BN to RBN crossover line. We also discuss the role of friction and show that particles which differ only for their frictional properties segregate in states depending on the tapping acceleration and frequency.

Quaternary sandstones, northeast Jordan: Age, depositional environments and climatic implications

OSL dating of weakly consolidated, root-bound, non-calcareous quartz arenites in northeast Jordan, currently assigned to the Plio–Pleistocene Azraq Formation, suggests a Middle Pleistocene (652 ± 47 ka) age. The sandstones are up to 15.5 m thick and overlain by a 2.5 m thick Holocene gypcrete caprock. Facies and textural analyses suggest that the sandstones are predominantly aeolian in origin, mainly derived from Tertiary sediments exposed close to the depositional site. The sands were transported by the prevailing NW winds and deposited in a broad, relatively flat sand sheet environment. Rhizoliths occur throughout the sandstones, mainly as long, downward tapering, vertical tap roots, rarely branched and with few laterals. Microscopic examination of root cores replaced by carbonate reveals the presence of alveolar fabrics, possible needle fibre calcite, calcified organic filaments of fungal, root vessel and root hair origins, characteristic of low magnesium beta calcretes, typical of humid climates. Morphologically the roots resemble modern shrub-like species typical of desert environments where water availability at the surface and in the subsurface was sufficient to support an effective vegetation cover. Plots of stratigraphic variations in root length, root spacing and root frequency reflect temporal variations in the water table level and precipitation during sand deposition. All three parameters show a similar crude cyclicity consistent with fluctuations in the level of the water table with the most moist phase beneath the predominantly waterlain Holocene gypcrete when trees appeared for the first time. The gypcrete signifies a change to temporary wetter conditions and may mark the boundary between the Pleistocene and Holocene in this area. Although pedogenic horizonation is poorly developed, especially in desert sands, the beta calcretes and rhizocretions typically form within active soil zones. Soils do not form where rainfall is < 150 mm per year, and above 350 mm complete leaching of the edaphon occurs. However, above 300 mm per year shrubs are replaced by grassland, hence rainfall is inferred to have been 150–300 mm per year, much higher than the < 50 mm in the area today. The age of the sandstones may correlate with isotopic event 17, dated at 659 ka, when the Pleistocene climate in Jordan was characterised by arid to semi-arid phases interrupted by shorter more humid phases, when the water table was higher and the precipitation/evaporation balance greater than today.

Slow compaction of granular systems

The dynamics of granular compaction under vertical tapping is experimentally andnumerically studied for isotropic and anisotropic grains. It is shown that if convection takesplace in the medium, it has a strong influence on the compaction dynamics. The localbehaviour of the grains during compaction and the consequences for the global propertiesof the medium are investigated.