Types Of Motion Research Articles

EARTHQUAKES FELT in the NORTH CAUCASUS in 2020: VERKHNE-FIAGDON EARTHQUAKE on JANUARY 26, 2020 with KR=11.2, I0=5 and JEYRAKH EARTHQUAKE on MAY 24, 2020 with KR=10.6, I0=4

In 2020, two significant earthquakes were registered in the south of the Republics of North Ossetia-Alania and Ingushetia: on January 26 with KR=11.2 and on May 24 with KR=10.6. The earthquakes occurred in different seismotectonic conditions. The source of the first event was formed within the Adaykom Kazbek fault, and the source of the second event – within the Karmadon zone of occurrence of earthquake sources. The January 26 earthquake, named the Verkhne-Fiagdon, became the strongest instrumentally recorded earthquake in North Ossetia since the beginning of seismological observations on this territory. It was felt in 19 settlements with the intensity from 2 to 4–5. The calculated intensity in the epicenter is estimated as I0=5. According to the focal mechanism solution, the Verkhne-Fiagdon earthquake occurred under the influence of prevailing compres sive stress. The type of movement in the focus is reverse fault with significant strike-slip component. The earth quake on May 24, named the Jeyrakh earthquake, was felt in 12 settlements with intensity from 2 to 4. Tensile stresses oriented in a south-west direction prevailed in the focus. The type of movement is a normal fault on both planes, with minor strike-slip components. Information on historical seismicity in the focal zones of both earth quakes is given for the last 150 years.

CHERNOGORSKOE-I EARTHQUAKE on DECEMBER 12, 2020 with KR=12.9, Mw=4.8 (GCMT), I0=5–6 in the CHECHEN REPUBLIC

On December 12, 2020 at 21h29m GMT, a significant event with KR=12.9, Mw=4.8 occurred on the territory of the Urus-Martan district of the Chechen Republic. Its epicenter belongs to the area of junction of the southern side of the Terek-Caspian foredeep with the structures of the northern slope of the Greater Caucasus and is associated with the Chernogorskaya zone of Possible Earthquake Sources (Mmax=6.5) of the Terek-Sunzha seismogenic region. The earthquake of December 12, called Chernogorsk-I, was felt in 57 settlements with an intensity from 2 to 5–6 by MSK-64. Based on the results of macroseismic surveys, the maps of shaking intensity in populated areas and isoseisms of 5, 4 and 3 points were constructed. The calculated intensity at the epicenter coincides with the observed one in nearest settlements and amounts to I0=5–6 points. The source was dominated by compressive stresses oriented submeridionally. The type of movement in the source is a reverse fault along both planes of sublatitudinal strike. The closeness of orientation of the nodal planes to the Chernogorsky fault orientation allows us to draw a conclusion about movement along this fault at Chernogorskoe-I earthquake.

Wavy mathematical modeling of dynamically reactive shear thinning materials under the influence of gravity and wavy structures amplitude

PurposeResultant leading equations are formed with non-linear partial differential equations by adopting a low Reynolds theory approximation. For a better and easier understanding of the role of physical features of the main problem, the equations are reduced to non-dimensional ordinary differential equations by incorporating the locally similar and non-similar dimensionless variables. In light of practical importance, all the significant findings are approximated by solving the equations with the assistance of a modified bvp4c built-in package. The effective speed, temperature and volume fraction of the same materials are displayed to address the behaviors of different controlling influences.Design/methodology/approachThis work is inaugurated to investigate thermal cycling, thermal striping and thermal stratification, which cause thermally induced damage during the wavy confined flow domains. Such physical constraints are imposed on the wavy surface while considering the wavy dynamics of shear thinning materials. The impact of gravity is assumed on the vertical wavy surface, which is observed as the main source for the wavy flow occurrence. The surface’s amplitude plays a critical role in generating a high temperature difference. The same phenomenon is further extended with the applications of thermal radiation, mixed convection and dynamical homogeneous/heterogeneous reactions.FindingsFor instance, the higher stratification factor causes a reduction in the liquid wavy speed and temperature, and the rising chemically reactive rate factor declines the volume fraction during the typical wavy motion of the materials. Moreover, the larger amplitude and mixed convective factor reduced and uplifted the speed of the materials, respectively. The surface resistive forces are monitored with the graphical visualization of local similar skin friction and are determined larger by varying the Weissenberg and mixed convective factors. The affective liquid speed, temperature and volume fraction are plotted to address the behaviors of different controlling factors. These impacts are listed, i.e. with higher stratification factors, a reduction is noticed in the liquid velocity and temperature. On the other hand, an opposite depict is noticed for higher heat generation factors. The reduction in volume fraction is reported with variation in the reaction factor and Schmidt number.Originality/valueAfter carefully assessing the previously referenced work, it is evident that the literature has yet to incorporate thermally stratified Williamson fluid. Meanwhile, the motion of the materials is noticed due to the gravitationally affected wavy surface. Such physical phenomenon is further approximated by testing a dynamical reaction during its motion. An effective presentation of all the outcomes is portrayed via graphs and approximated numerical results.

Type synthesis, analysis, and prototyping of 4R1H mechanisms

Abstract The article introduces a novel class of 4R1H mechanisms, where 4R indicates four revolute joints and 1H indicates one helical joint. The paper starts with the type synthesis of these mechanisms, which involves combining two kinematic chains with planar and cylindrical motion types into a single closed-loop kinematic chain. If we fix any link in such a chain, we get a workable mechanism. The synthesis procedure considers two options for the relative arrangement of these two kinematic chains. Adding an H joint to the kinematic chain allows us to design mechanisms whose output link performs spatial motion. Using the proposed synthesis procedure, we develop a family of 4R1H mechanisms. Next, we choose one mechanism as a representative example and consider its mobility, singularity, kinematic, and dynamic analysis. Using screw theory, we confirm the mechanism has one degree of freedom and determine its singular configurations. Kinematic analysis provides closed-form expressions to calculate displacements, velocities, and accelerations of all the mechanism links. Dynamic analysis uses these results to compute the motor torque required for one motion cycle. To verify the suggested analytical algorithms and obtained results, we use computer-aided design tools, which allow us to develop virtual and physical prototypes.

Same Same but Different: Why Both Sport-Specific Cutting Tasks and Generic Change-Of-Direction Tasks Might Need to Be Considered to Prevent ACL Injury

OBJECTIVE: To compare knee abduction moment (KAM) magnitudes between a generic 180° pivot turn (modified 505 change-of-direction test; m505) and a handball-specific sidestep cut, and to assess ranking consistency. Additionally, to examine the resultant ground reaction force (GRF) and its frontal plane moment arm to the knee to comprehend their contributions to KAM. STUDY DESIGN: Observational laboratory study. METHODS: High-level female handball players (n = 45) performed the m505 and handball-specific sidestep cut. Resultant GRF, its frontal plane moment arm to the knee, and KAM were obtained and subsequently compared between the tasks. Rank correlation coefficients were employed to assess if variables of both tasks are related. RESULTS: Peak KAM was similar for the m505 and the sidestep cut (1.79 (0.95 – 3.53) Nm/kg vs. 1.64 (0.34 – 3.60) Nm/kg; rB = .25; p = .14). The ranking of the players' peak KAM differed substantially ( rS = 0.26, p = .084), suggesting that different tasks could classify the same player with different injury risk. The m505 generated lower resultant GRF (24 ± 4 N/kg, 95% CI [23, 24] vs. 33 ± 9 N/kg, 95% CI [31, 35]; d = 1.30; p < .001) but longer frontal plane moment arms (7.8 ± 1.8 cm, 95% CI [7.3, 8.4] vs. 5.4 ± 1.5 cm, 95% CI: [5.0, 5.8]; d = 1.36; p < .001) than the sidestep cut. CONCLUSION: A difference in individual ACL injury risk assessment depending on movement type was revealed. While KAM magnitudes were similar across direction-change tasks, player rankings differed. The contributions of resultant GRF and frontal plane moment arms to peak KAM varied between tasks, underscoring the importance of task-specific and individualized injury prevention.

Differences in the force exerted during wrist movements are explained by a general mathematical model

The goal of previous efforts has been to create hand prostheses with natural movements. Researchers have used tools to identify patterns in muscle signals associated with different hand movements. While many studies have successfully classified types of hand movements, it's important to analyze speed and strength to ensure that the resulting movements are natural. In this study, 16 healthy subjects were evaluated for (two) different forces and (six) hand movements using surface electromyographic (sEMG) records. A mixed effects model was used to examine the relationship between force and forearm sEMG signals. The results showed high R2 values (median 0.9) and significant random effects, indicating that sEMG signals can explain variations in force signals during different hand movements by introducing the type of movement as part of the random effects of the model.

Enhancing actuation control in monolithic liquid crystal elastomer films with dual heat and light responsiveness

This study presents a dual heat and light-responsive monolithic liquid crystal elastomers (LCEs) film designed to enhance actuation control. The LCE films were capable of various motion types, including curvature reversal, oscillation, and sustainable flipping. By incorporating an azobenzene compound, the films exhibited additional functionalities such as enhanced curvature reversal, accelerated oscillation, and the ability to lock continuous flipping motion upon light stimulation. Furthermore, by adjusting the aspect ratio (AR) of a single film, different thermal motion states were realized, demonstrating the flexibility of this approach. Observations using an NIR camera confirmed temperature fluctuations corresponding to thermal exchange, and the influence of UV light on motion regulation was quantitatively analyzed. The ability to regulate motion through dual stimuli paves the way for improved dynamic motion control and thermal management in advanced robotic applications.

Creation of two-dimensional circular motion of charge qubit

We suggest a nanoelectromechanical setup which generates a particular type of motion—the circular motion of mesoscopic superconducting grain, where motion is described by entangled nanomechanical coherent states. The setup is based on mesoscopic terminal utilizing the ac Josephson effect between the superconducting electrodes and the grain, operating in the regime of the Cooper pair box controlled by the gate voltage. The grain is placed on the free end of the suspended cantilever, performing controlled two-dimensional mechanical vibrations. Required functionality is achieved by operating two external parameters, bias voltage between the superconducting electrodes and voltage between gate electrodes, by which the nanomechanical coherent states are formed and organized in a pair of entangled cat-states in two perpendicular spatial directions, which evolve in time in the way to provide a circular motion.

Waves and non-propagating mode in stratified and rotating magnetohydrodynamic turbulence

In this study, we consider a freely decaying, stably stratified, and rotating homogeneous magneto-hydrodynamic (MHD) turbulent plasma with a vertical background magnetic field (B0=B0ẑ), aligned with the density gradient (with a constant Brunt–Váisálá frequency N) viewed in a frame rotating uniformly around the vertical axis (Ω0=Ω0ẑ). Quasi-linear theory is used to analyze the flow dynamics for an inviscid and non-diffusive Boussinesq fluid. We perform a normal mode decomposition emphasizing three types of motions: a non-propagating (NP) mode, which is no longer a vortex mode, and slow and fast magneto-inertia-gravity waves. The total energy as well as the L2 norm, say Γ, of the magnetic induction potential scalar (MIPS), which remains similar to the potential enstrophy for non-magnetized rotating and stratified flows, are inviscid invariants. In contrast with the potential vorticity for non-magnetized rotating and stratified flows, the MIPS is not affected by system rotation in the quasi-linear limit, and this is the effect of rotation which presumes an inverse cascade of energy in the equilibrium statistical mechanics. We characterized the system setting up our investigation from the point of view of equilibrium statistical mechanics in the limit of small Froude number and small Alfvén–Mach number. In this limit, the non-propagating quantity Γ can be approximated by its quadratic part that explicitly depends only on the vertical component of the fluctuating magnetic field and the density fluctuations. We demonstrate that the partition function restricted to the non-propagating manifold does not indicate an inverse cascade of energy.

Dynamic response of three different floating platform (OC4, BSS, GVA) using multi-segment mooring system

The design of mooring lines for floating platforms is an essential task to guarantee structure survivability and its components under different metocean conditions. This paper focuses on the application and comparison of the MSM-BMW system across various types of semisubmersible platforms, including the OC4-DeepCwind, the braceless semi-submersible (BSS) with three catenary mooring lines, and the drilling rig GVA 4000 with eight mooring lines. The performance of the BMW mooring system for these three platforms is compared under operational and survival conditions. The hybrid mooring concept is a multi-segment mooring (MSM) arrangement of the catenary and taut, including single buoy and multi-clump weight (BMW), generally named MSM-BMW. Hydrodynamic responses and mooring forces are compared between original and hybrid systems under regular and irregular wave conditions. The dynamic response of the platform is performed utilizing both Morrison theory and three-dimensional radiation/diffraction theory based on the boundary element method (BEM) in ANSYS-AQWA software. The results show that using BMW on the three floating platforms significantly reduces platform motion at low frequencies, with minimal effect on wave-frequency resonance. However, the BMW system increases mooring force at wave frequency, while having a smaller effect at low frequencies. The effectiveness of the BMW system varies across platforms and motion types. The BSS platform shows significant improvement in surge motion, while the GVA platform has the smallest ratio in heave motion. Additionally, the BSS platform demonstrates the least response in pitch motion.

A voxel-based 3D indoor model to support 3D pedestrian evacuation simulations

Three-dimensional (3D) indoor models enable realistic simulation of pedestrian evacuations in 3D space. However, existing indoor models do not fully identify navigable spaces located above/below physical components (e.g., chairs, stairs, desks), and the connections between these spaces and their navigable surfaces remain underexplored. These limitations hinder the accurate modelling of 3D pedestrian motions during evacuations. To address the shortcomings, we present novel automatic approaches to create a voxel-based 3D indoor model. First, based on different types of 3D motions, indoor spaces are automatically identified as freely navigable spaces, navigable spaces under conditions and non-navigable spaces. Then, navigable surfaces are identified to simulate moving above/below in 3D space. Vertical links are identified to connect the spaces and surfaces at different heights. A 3D pathfinding approach is subsequently developed to validate the model’s effectiveness. Finally, we evaluate the created model’s accuracy, robustness and efficiency across different voxel sizes. The primary findings are: 1) as voxel size increases, accuracy decreases, robustness changes and efficiency improves; 2) with very small voxel sizes, identification becomes challenging, while larger voxel sizes prevent some spaces and vertical links from being identified; and 3) indoor spaces with complex geometries require more time for identification. Our key contributions are: 1) an approach for automatically identifying indoor spaces for 3D motions; 2) two approaches for automatically identifying navigable surfaces and vertical links; and 3) a 3D pathfinding approach considering distinct 3D motion costs. This work advances 3D modelling to facilitate more realistic evacuation simulations.

Self-adaptive weighted physics-informed neural networks for inferring bubble motion in two-phase flow

Modeling complex fluid flow using machine learning is increasingly recognized as a valuable approach for revealing multiphase fluid phenomena. Bubble dynamics represent a classical two-phase flow problem that plays a crucial role in various engineering domains. In this paper, physics-informed neural networks (PINNs) are applied to facilitate incompressible two-phase bubble motion modeling by integrating governing equations and interface evolution equations. The loss function of PINNs consists of multiple loss terms, including initial and boundary conditions constraints, partial differential equations residuals, and volume fraction constraints. The performance of PINNs is influenced by the competing effects of these loss terms. Therefore, we introduce a heuristic adaptive weights approach to automatically adjust loss weights for each training point, avoiding manual tuning and improving the accuracy of PINNs. We investigate typical bubble motion cases, specifically focusing on bubble rising and breakup, to showcase the capabilities of the proposed method. We explore the impact of weights and present the results in comparison to the baselines. Through the bubble breakup case, we illustrate that our model shows superior performance even with more complex scenarios. Then we further discuss the generalization and robustness of our model, showing their indispensability over traditional solvers in gas–liquid two-phase systems. Specifically, we accelerate computation speed in transfer learning without the need to modify the original model. We also show that our method effectively solves ill-posed problems, such as those without initial data or with incomplete or noisy boundary conditions.

Zonal flow instability induced by nonlinear inertial waves in a librating cylinder with sloping ends

This paper compares the nonlinear dynamics of two key types of motion observed in a rotating liquid-filled cavity subject to external forcing: an inertial wave attractor and resonant inertial oscillations (inertial modes). Experiments are performed with a cavity having a specific shape of a truncated circular cylinder delimited by plane-parallel end walls inclined with respect to the cylinder base. The cavity rotation axis coincides with the axis of the cylindrical surface. Libration-type forcing is introduced by harmonic modulation of the background rotation frequency. The sloping end walls break the axial symmetry of the liquid domain: the shape of the axial-radial cross sections varies from parallelogram to rectangle depending on the azimuthal angle. It is found that, regardless of the liquid response type (wave attractor or inertial modes), the transition from linear to nonlinear dynamics follows the scenario of triadic resonance instability. However, the time-averaged zonal flow responds differently to the primary wave instability. Inertial-mode instability generates a system of azimuthally periodic averaged vortices, whose frequency coincides with the subharmonic frequency of the triadic resonance. At high libration amplitudes, a low-frequency component appears in the azimuthal velocity spectrum, being associated with excitation of the retrograde system of vortices. The development of the weakly nonlinear regime of the wave attractor is accompanied by the instability of the viscous boundary layers—fine-scale pattern formation occurs close to the reflection zones of the attractor branches at the cylindrical sidewall. In the strongly nonlinear wave regime, coherent vortex structures are excited, performing azimuthal and radial drifts.

Sieve element traits differ in pulvini and petioles of Mimosa (Leguminosae, Caesalpinioideae) with different types of leaf movement

The vascular system, particularly the phloem, has been considered a key issue in driving the pulvini functioning. Studies comparing phloem in different leaf regions and in plants with different leaf movement types can help clarifying the aspects involved in the pulvini functioning. Here, we investigated the morphological traits of the sieve tube elements in a comparative way between pulvini and petioles of Mimosa pudica (a legume with fast leaf movements) and M. caesalpiniifolia (a legume with slow leaf movements). Pulvini and petioles were analyzed under light and transmission electron microscopy. Sieve elements in pulvini had thicker walls than those of petioles, especially in M. pudica. Nacreous walls occurred in the sieve elements of M. pudica pulvini. Dispersive and non-dispersive P-proteins and P-plastids occurred in the pulvini and petioles of both species. The marked differences in the lumen area and cell wall features of the sieve elements between pulvini and petiole indicate the specialization of the phloem in the pulvinus functioning.

Effects of Soil–Structure Interaction on the Seismic Response of RC Frame–Shear Wall Building Structures Under Far-Field Long-Period Ground Motions

This paper focuses on the effect of soil–structure interaction (SSI) on the seismic response of high-rise RC frame–shear wall structures under far-field long-period ground motions. Elastic–plastic time–history analyses were performed using ABAQUS. The effects of the ground motion type, soil type, and structural frequency on the seismic response are analyzed and quantitatively evaluated. On this basis, the influence mechanism of SSI on the seismic response under far-field long-period ground motions is discussed and revealed through a ground motion spectrum analysis. The results show that the consideration of the SSI effect leads to an increase in the displacement response and a decrease in the shear response. The SSI coefficient of the base shear is all less than 1, ranging from 0.5 to 1. The SSI effect under far-field long-period ground motions is more pronounced than that under ordinary ground motions. The shear force reduction in the current code may not be applicable to the structural design considering the SSI effect under far-field long-period ground motions. The displacement response amplification of the SSI effect on loess soil (Site 2) is more remarkable than that on sand soil (Site 1). The SSI effect can reduce the structural frequency, especially for the structures with fewer floors on the softer soil site. The “bimodal characteristic” of the acceleration response spectrum for far-field long-period ground motions may lead to shear force amplification when SSI is considered.

Numerical simulation of cathode-spot crater and droplet formation with linear and circular motion process

Abstract In this paper, a three-dimensional cathode spot erosion model is proposed to study the development of cathode spot motion 
process on the surface of copper cathode. The formation and development process of cathode spots motion without external 
magnetic field is studied. In this model, energy flux density, pressure, and current value are considered as external parameters. 
The simulation results compared the cathode spot ablation trajectories and temperature distribution under different motion 
forms and motion velocities. The results indicated that during the spots expansion process, the flow of liquid metal will form a 
convex structure on the surface of the cathode and a hollow structure inside the cathode. Comparing different motion types, the 
annular motion significantly increased the roughness of the cathode surface. With the increase of the speed of spots movement, 
the interaction between the craters is significantly weakened, which will reduce the temperature and the roughness of the 
cathode surface. The simulation results are consistent with the experimental results.

A new approach to historical migratory movements based on surnames: the case of Spain

A data mining technique called Self-Organized Maps (SOM) was used to select the surnames with populational information (monophyletic) to be used in the reconstruction of past demographic processes, in order to show the historical population migrations that have generated the current structure of the Spanish population. The technique made possible to identify groups of surnames with the same origin. Once the origin of each surname has been established, we can assume that each surname found outside its origin would have moved, at some point in the past, out of that original area, which allows to study historical movements. The observed movements reveal the existence of two main migratory arcs. Both migrations have moved along the coast; the first following the Mediterranean and the second following the Cantabrian Sea. It appears that these two arcs are those that have provided the backbone of the Spanish population, dividing it into two halves that would reach the limits of areas of influence of these arcs. Several types of movement have taken place (Isolation due to distance, Short-distance movements, Medium-distance movements, Long-distance movements). Those of short-medium distance have been the most frequent and most determinant in the current structure.

Detectability of multi-dimensional movement and behaviour in cattle using sensor data and machine learning algorithms: Study on a Charolais bull

The development of motion sensors for monitoring cattle behaviour has enabled farmers to predict the state of their cattle's welfare more efficiently. While most studies work with one dimensional output with disjunct behaviour categories, more accurate prediction can still be achieved by including complex movements and enriching the sensor algorithm to detect multi-dimensional movements, i.e., more than one movement occurring simultaneously. This paper presents such a machine-learning method for analysing overlapping independent movements. The output of the method consists of automatically recognized complex behaviour patterns that can be used for measuring animal welfare, predicting calving, or detecting early signs of diseases. This study combines automated motion sensors (i.e., halter and pedometer) for ruminants known as RumiWatch mounted on a Charolais fattening bull and camera observation. Fourteen types of complex movements were identified, i.e., defecating-urinating, eating, drinking, getting up, head movement, licking, lying down, lying, playing-aggression, rubbing, ruminating, sleeping, standing, and stepping. As multiple parallel binary classificators were used, the system was able to recognize parallel behavioural patterns with high fidelity. Two types of machine learning, i.e., Support Vector Classification (SVC) and RandomForest were used to recognize different general and non-general forms of movement. Results from these two supervised learning systems were compared. A continuous forty-eight hours of video were annotated to train the systems and validate their predictions. The success rate of both classifiers in recognizing special movements from both sensors or separately in different settings (i.e., window and padding) was examined. Although the two classifiers produced different results, the ideal settings showed that all forms of movement in the subject animal were successfully recognized with high accuracy. More studies using more individual animals and different ruminants would increase our knowledge on enhancing the system's performance and accuracy.

Aging and the visual perception of rigid and nonrigid motion

Nonrigid forms of motion are commonplace in everyday life. Given previously documented age-related deteriorations in various tasks involving motion (discriminating speed, identifying motion direction, etc.), an experiment was conducted to evaluate the potential effect of age upon the visual ability to detect rigid and nonrigid object motion. Thirty younger and older observers participated in the experiment (mean ages were 19.9 and 75.8 years, respectively). As has been done multiple times in the past, the individual motions of object vertices were manipulated to simulate either rigid motion (rotation in depth, with or without precession) or two different types of nonrigid motion (also rotation in depth with or without precession, but with added object deformation). In confirmation of previous research, there were large effects of nonrigid motion type and precession upon the ability to differentiate between rigid and nonrigid object motion. There was also a large effect of age, such that the discrimination performance of the younger observers was 49.6% higher than that exhibited by the older observers. In this first ever study of aging and nonrigid object motion perception, we thus find that aging is associated with a substantial impairment in the ability to visually perceive object nonrigidity.

Slow global motions in biosolids studied by the deuteron stimulated echo NMR experiment.

Recent 15N R1ρ-relaxation studies have shown that proteins in the solid state undergo slow, low amplitude global motion in the sub-millisecond time range. This range is at the edge of the time window for R1ρ experiments and, therefore, the motional parameters obtained by this method are not precise or reliable. In this paper, we present a 2H stimulated echo study of this type of molecular dynamics. The 2H stimulated echo experiments on a static sample allow for direct measurement of the correlation function in the time range of 10-6-10-1s, making them well suited to study this type of molecular mobility. We have conducted a detailed analytical and numerical comparison of the correlation functions obtained from the relaxation and stimulated echo experiments, which are generally different. We have identified conditions and algorithms that enable a direct comparison of the relaxation and stimulated echo experimental results. Using the protein GB1 in the form of a lyophilized powder, we have demonstrated that 15N R1ρ-relaxation and 2H stimulated echo experiments yield essentially the same slow-motion correlation function. Surprisingly, this type of motion is observed not only in the protein sample but also in the tripeptide and single amino acid solid samples. The comparison of data measured in these three samples at different temperatures led us to conclude that this slow motion is, in fact, ultrasonic phonons, which seem to be inherent to all rigid biological solids.