Influence of reflected waves at the bonded boundary in double-layered thickness-shear resonator using α-quartz

The influence of the reflected waves at the bonding boundary on the resonance waveform and temperature characteristics was investigated using α-quartz (QZ). The double-layered resonator specimen was fabricated using 129.55°Y- and 0°Y-cut QZ substrates with the thickness ratio x=0.520. The temperature characteristic at the range from 100°C to 300°C was deviated from the calculated values estimated by the equations considering thickness and electric flux density ratio proposed in the previous work, and the resonant waveform of the specimen was deteriorated as compared with that of single-layer resonators. In order to clarify these phenomena, the phase matching conditions and total amplitude in the specimen were examined. As a result, it was clarified that increase of the amplitude in the layer with lower acoustic impedance was affected to the temperature characteristic, and acoustic losses due to reflection / transmission at the bonding boundary was affected to the total amplitude of resonance.

Acoustic wave response to groove arrays in model ears

Many mammals and some owls have parallel grooved structures associated with auditory structures that may be exploiting acoustic products generated by groove arrays. To test the hypothesis that morphological structures in the ear can manipulate acoustic information, we expose a series of similar-sized models with and without groove arrays to different sounds in identical conditions and compare their amplitude and frequency responses. We demonstrate how two different acoustic signals are uniquely influenced by the models. Depending on multiple factors (i.e., array characteristics, acoustic signal used, and distance from source) the presence of an array can increase the signal strength of select spectral components when compared to a model with no array. With few exceptions, the models with arrays increased the total amplitude of acoustic signals over that of the smooth model at all distances we tested up to 160 centimeters. We conclude that the ability to uniquely alter the signal based on an array’s characteristics is evolutionarily beneficial and supports the concept that different species have different array configurations associated with their biological needs.

Global mapping of the nonstationary M2 internal tide using Argo data

<p>Data from Argo floats equipped with Iridium communications are used to obtain a global map of the total amplitude (or variance) of the M<sub>2</sub> internal tide. The results are confirmed by a comparison with the High Resolution Empirical Tide (HRET) model, based on satellite altimetry. While HRET only contains the stationary component, with a fixed phase difference to the astronomical tide, the present results capture the total amplitude, including the nonstationary component. The time scale over which the nonstationary component is decorrelated is also obtained. We estimate the global average ratio of total to stationary semidiurnal internal tide variance to be more than 10. In terms of the ratio of nonstationary to total semidiurnal internal tide variance, the semidiurnal nonstationary variance fraction (SNVF), this translates into a global average ratio of about 90%. The Argo <em>in situ</em> observations provide a valuable ground-truth for the geographical variability of the internal tides. The latter is key to predicting the magnitude and distribution of the mixing that ultimately results from the tides.</p>

International observational campaign of the 2014 eclipse of EE Cephei

Context. EE Cep is one of few eclipsing binary systems with a dark, dusty disc around an invisible object similar to ε Aur. The system is characterised by grey and asymmetric eclipses every 5.6 yr that have significant variations in their photometric depth, ranging from ∼0.m5 to ∼2.m0. Aims. The main aim of the observational campaign of the EE Cep eclipse in 2014 was to test the model of disc precession. We expected that this eclipse would be one of the deepest with a depth of ∼2.m0. Methods. We collected multicoloured observations from almost 30 instruments located in Europe and North America. These photometric data cover 243 nights during and around the eclipse. We also analyzed low- and high-resolution spectra from several instruments. Results. The eclipse was shallow with a depth of 0.m71 in the V band. The multicoloured photometry illustrates small colour changes during the eclipse with a total amplitude of order ∼+0.m15 in the B − I colour index. We updated the linear ephemeris for this system by including new times of minima, measured from the three most recent eclipses at epochs E = 9, 10, and 11. We acquired new spectroscopic observations, covering orbital phases around the eclipse, which were not observed in the past and increased the data sample, filling some gaps and giving better insight into the evolution of the Hα and Na I spectral line profiles during the primary eclipse. Conclusions. The eclipse of EE Cep in 2014 was shallower than expected, measuring 0.m71 instead of ∼2.m0. This means that our model of disc precession needs revision.

The precession of Mercury’s orbit

Within the framework of classical mechanics the influence of the planets in the solar system to the precession of the orbit of Mercury is investigated. It is shown that the average offset of the perihelion of mercurys orbit computed within the flat limited tasks is 556,5 angular seconds per century and coincides with the observation data with relative accuracy of 2,5%. Incomplete overlap between the computed average offset and observations can be explained by the presence in observations offset oscillatory components with a total amplitude up to 20 angular seconds and periods from several years to several decades.

Influence of the elastic deformations on the form factor of polyhedral nanocrystals: the illustrative example of the pseudomorphic inclusion

Using an analytically tractable example, the pseudomorphic inclusion, this article examines the influence of elastic deformations on the form factor of polyhedral nanocrystals. A control parameter, the total amplitude of the variation of the complex density phase, is identified and it is shown that for low enough deformations the characteristic asymptotic behaviours as a function of the scattering vector associated with the polyhedral crystal shape are preserved, leading to a strong contrast in the dependence of the form factor on orientation. Using the sections method, it is explained why these results can be generalized to more realistic elastic situations.

a0(980)–f0(980) mixing in χc1 decay

We investigate the isospin breaking in the ${\chi _{c1}} \to {\pi ^0}{\pi ^ + }{\pi ^ - }$ and ${\chi _{c1}} \to {\pi ^0}{\pi ^0}\eta $ decays and its relation to the a0(980) – f0(980) mixing, which was measured by the BESIII Collaboration. The isospin violation is introduced through the use of different masses for the charged and neutral kaons, either in the propagators of pairs of mesons created in the χc1 decay, or in the propagators inside the T matrix. We find that the most important effect in the total amplitude is the isospin breaking inside the T matrix which is essential to get a good agreement with the experimental measurement of the mixing.

High Potential of Magnet on the Performance of Dual Piezoelectric Fans in Electronics Cooling System

Recently, piezoelectric fan has gained attention as potential active cooling method for electronics devices. Even though the piezoelectric requires high voltage, there are findings to overcome the shortcomings. Adding on a magnet at the tip of the piezoelectric fan to activate other magnetic passive fans is one of the methods to increase the total amplitude generated by the fans. This paper will discuss on the performance of integrated piezoelectric fan with passive fans (later refer to magnetic fans) to enhance the heat transfer in cooling system. A repulsive force produced by the magnets will cause the magnetic blades to oscillate together with the piezoelectric fan. The paper will focus on the optimization parameters of the magnets for selected dimension of piezoelectric fan. The parameters under investigation are the position of the magnet on the piezoelectric fan, number of magnets on each blades and orientation of blades with respect to adjacent blade. Results show that the magnet at middle location of extensive blade with double magnets generate the largest amplitude, 80% better than fan without magnet and for dual integrated piezoelectric fan with magnetic fan, radial orientation gives better result by 25%. By increasing the total amplitude using magnetic force, power consumption can be reduced while the heat transfer performance can be enhanced. it shows a good agreement for positive heat transfer and thermal resistance improvement compared to natural convection.

Possibilities of Instrumental Recording of Quantitative Characteristics of the Cranial Rhythm

Introduction. The cranial rhythm is represented by the rhythmic movement of the skull bones associated with the cyclic changes in production and pressure of the cerebrospinal fluid. The existing methods of instrumental recording of the quantitative characteristics of the cranial rhythm are either invasive, either contact, or very complex. Objective. To evaluate the EHF-bioradiolocation method as a method of recording of the quantitative characte-ristics of the cranial rhythm. Methods. Twenty volunteers were examined. At the first stage of the study, we determined the optimal conditions for registering the cranial rhythm with the help of the EHF bioradiolocator. At the second stage, the volonteers’ cranial rhythm was registered with the use of an EHF-bioradiolator. Then the volonteers were subjected to osteopathic diagnostics and correction. After that the cranial rhythm was recorded again. Results. For the first time we registered the cranial rhythm with the help of the EHF-bioradiolocator. In most cases, the frequency of the cranial rhythm recorded by the device coincided with the frequency determined by an osteopath. After the osteopathic treatment, the total amplitude of the oscillations increased in all the patients. Assessment of changes in the frequency of the cranial rhythm was difficult due to the presence of several harmonics. Conclusion. With the help of the EHF-bioradiolocator, it is possible to register the quantitative characteristics of the cranial rhythm - frequency and amplitude. The methodology we developed is safe and relatively simple. It is non-contact, and can be used both for diagnostic purposes, and for monitoring and evaluation of the treatment results.

Fourier Descriptors for Improved Analysis of Distortion Transfer and Generation

For fan/compressor design, quantifying distortion transfer and generation bladerow by bladerow through a fan/compressor is important to understand the flow physics and predict performance. What is needed are descriptors capable of describing distortion profiles with both high and low distortion content and account for the reshaping of distortion profiles. Four key parameters were identified as desirable to quantitatively capture distortion transfer, generation and effects on performance: distortion magnitude, shape, severity and phase. A set of distortion descriptors based on Fourier analysis are shown to quantitatively capture distortion magnitude, shape and phase change across bladerows. These Fourier descriptors are modal amplitude, total amplitude, and phase shift. When used together, these Fourier descriptors can be used to qualitatively describe any conceivable profile shape for any parameter.