Possibilities of ultrasound methods in the diagnosis of decompression sickness

Aim of the work: to conduct a comparative analysis of methods of ultrasound examination of the right heart with audio and visual indication of intravascular decompression gas formation in divers after diving.Materials and methods. An examination of the right heart in divers after 152 man-descents was carried out. Intravascular decompression gas production was assessed by ultrasound using sound location based on the Doppler effect and transthoracic two-dimensional echocardiography.Results and discussion. Both methods make it possible to determine intravascular decompression gas formation after a diving descent, correlate with the clinical picture of acute decompression sickness and should be used in the medical support of diving descents. At the same time, the method of ultrasound examination based on transthoracic two-dimensional echocardiography turned out to be more sensitive in determining gas bubbles in the right heart as compared to auditory location with the Doppler effect.

Model of Signal Mark Detection in a Passive Sonar System

Modeling of broadband and narrowband signal mark detection is widely used for sonar and radar systems. In this work, the problem is considered in relation to hydroacoustics. The paper describes the formation of a stream of correctly detected and false signal marks and calculation of estimates of their parameters, taking into account the antenna characteristics as well as the processing parameters of the system being simulated. Also considered are the realistic distribution of false signal marks by heading angles and the influence of the Doppler effect on the estimation of the mark parameters. The resulting model can be used in simulation systems, in the formation of a stream of detected signal marks, and the development of tracking algorithms. The model can be also used for predictive calculations that determine the probability of detecting signal sources and their characteristics

Multi-HAPS Network Implementation within 3GPP’s NTN framework for 5G and beyond

High Altitude Platform Station (HAPS) is part of the 3GPP defined non-terrestrial network (NTN) infrastructure for 5G networks. Various technical studies by 3GPP have addressed NTN-based implementations and have significantly studied satellite-based scenarios. However, the study does not sufficiently address HAPS or multi-HAPS based scenarios specifically. Though HAPS, is captured under Unmanned Aerial Systems (UAS), it has unique operational realities that set it apart from other NTN platforms. For instance, HAPS come in different variants of fixed-wing, balloons and airships. This paper highlights the need for expanded studies specifically aimed at HAPS for more seamless integration. The work also analyses the Doppler effect associated with fixed-wing HAPS systems to further demonstrate how operational scenarios may differ for these platforms and the need for targeted studies. HAPS is expected to contribute significantly to the NTN-based implementations and may require more specialised considerations within the 3GPP NTN technical specification process, especially for 5G and beyond 5G (B5G) networks.

The misunderstood Sagnac effect

The Sagnac effect of first order (in one-way light) is shown to explain the aberration observed in the very long base interferometry tests. This fact is also consistent with Sagnac’s results and with the observed stellar aberration. The Sagnac effect of second order (in two-way light) is shown to be real, but not observable, in the experiments that were done by Michelson and Morley. However, it is also shown that the same second order effect is observable in the Pioneer anomaly. The Doppler effect of second order is also demonstrated to explain the cosmic red shift, due to a radial ether wind.

Lorentz, Poincare, Einstein, and Minkowski failed—and modern physics is still failing—to know the time Doppler effect

We know that the Doppler effect (DE) is the difference between the frequency at which signals (or particles) leave a source and that at which they reach an observer, caused by relative motion. We also know that, based on the relationship of the frequency with wavelength, energy, and period, one can express the DE through these quantities. But, it is also very well-known relationship between frequency and time. Then, why modern physics fails to express the “time DE,” i.e., the DE through time)?

Several conjectures about the existence of the ether

The "zero result" of Michelson Morley's experiment was not enough to deny the existence of a fifth element---ether, as conceived by Aristotle. Hubble's explanation of the Doppler effect of the systematic cosmic the red shift was incomplete and needed to be introduced into the ether.The physical significance of universal gravitation constant reveals the possibility of the existence of ether. After much thought and logical reasoning, there is good reason to think that the ether is negative energy, stream of consciousness, and space itself, it combines with photons to build elementary particles, elementary elements, everything in the universe, including ourselves. In addition, it is feasible to explain the causes of gravitation, electromagnetic force, strong force and weak force from the perspective of the ether, which seems to be easier for us to understand. The most tragic conclusion is that the universe was created out of nothing and will eventually return to nothing.

Doppler estimation and compensation method for underwater target active detection based on communication signal

The integration of underwater detection and communication uses communication signals to detect a target actively, but the Doppler effect deteriorates the parameter estimation performance of the integrated system. To eliminate the influence of the Doppler effect, a joint Doppler estimation and compensation method based on spectrum zooming and correction is proposed. Firstly, the synchronization signal is used to obtain the signal receiving delay and intercept the single-frequency signal segment in the received signal. Then, the discrete Fourier transform is used to find the frequency that corresponds to the maximum amplitude of the single-frequency signal segment. Finally, the frequency spectrum is refined and corrected within the range near the frequency. The Doppler factor is estimated and the received signal is compensated by the Doppler estimation value. The simulation results show that the proposed method improves Doppler factor estimation accuracy, increases the cross-correlation processing gain and improves DOA (direction of arrival) estimation performance, thus being robust to different Doppler effects.