Calculation Of Velocity Research Articles

How to assess pulse wave velocity during transthoracic echocardiography? Comparison of femoral, carotid and radial time to flow

Abstract Background Pulse Wave Velocity (PWV) is a key parameter for arterial stiffness assessment, which provides significant prognostic information in a wide range of patients. However, the access to the dedicated devices, additional time and logistics needed during the separate study limit significantly the feasibility of this important variable. Purpose Our aim was to elaborate the simplest and timesaving method for routine TTE assessment, noninvasive and in maximal way patient and user friendly. We tested pulsed wave velocity calculation with TTE (ePWV) which however includes the measurement of the distance between carotid and femoral artery and its simplification by using as a proxy time to the onset of blood flow in femoral artery (TF) with possible indexing to patient’s height for further standardization and inter-patient comparisons. In the second step we compared the utility of time to flow measured with linear probe in radial artery (TR) which my further simplify the procedure by easier access to radial artery. Methods We included 56 patients with wide age-range from 20 to 94 years(mean age 55 years; 65% female), who underwent TTE with Doppler examination of flow in left and right carotid (TC), femoral(TF) and radial arteries (TR) using respectively cardiac probe for carotid and femoral (for simplification and minimizing the time of the examination) and linear probe for radial arteries. Pulsed wave Doppler spectra were registered and times from R wave of ECG to onset of flow were measured as well as the distance between respective points of measurements. ePWV was calculated as the distance divided by estimated pulse wave transit time, see Figure 1. Results We found very good to good significant correlations, with p<0.0001, between parameters measured in respective left and right arteries (with r= 0.92 for femorals, 0.82 for carotids and 0.73 for radials respectively). Similarly, median times to flow did not differ significantly between left and right-sided arteries although numerically the right-sided values were a few miliseconds longer e.g. 139 (118-154) vs 133 (116 – 155) ms in respective femorals, p=ns. Calculated ePWV correlated significantly with time to flow in femoral artery (TF), underscoring its potential as a fast proxy parameter, r= -0.67, p<0.0001. Moreover, TF correlated well with TC, age and intima media thickness (IMT), whereas TR did not show significant relationships with those parameters, see Figure 2, compare left and right panels. Conclusions The assessment of ePWV by TTE is safe, fast and feasible with the possibility of further simplification while using time to flow in left or right femoral artery (TF). However analogous parameter obtained from radial artery did not show correlations neither with age nor with IMT as exponents of cardiovascular burden so could not be use in place of femoral examination. Time to flow measurements. Comparison of TF and TR correlations.

Effect of Lithospheric Thickness and Radial Mantle Viscosity Profile on Glacial Isostatic Adjustment Crustal Motions in North America

North America is experiencing vertical and horizontal crustal motion due to glacial isostatic adjustment (GIA). To explore these motions across central and eastern North America, GIA modelling was carried out employing the ICE-6G_C surface loading model. The Earth model response was determined for 500 3-layered mantle viscosity profiles at nine different lithospheric thicknesses, assuming a constrained density and elastic structure. The predictions were compared to observed velocities downloaded from the Nevada Geodetic Laboratory for selected Global Navigation Satellite System (GNSS) sites and were corrected for hydrological loading and current global ice change. The fit is assessed through a Root Mean Square (RMS) calculation of the residual velocities. Scanning across lithospheric thicknesses and viscosity profiles, the preferred models were compiled to assess the overall best fit for vertical, horizontal, and combined crustal motions. The horizontal and combined responses exhibit two optimal viscosity profile ranges dependent on the lithospheric thickness. The viscosity profile for thinner lithospheres (<120 km) is akin to other published profiles but inferred mantle viscosities shift by an order of magnitude at thicker lithospheres (≥120 km). The optimal viscosity for the vertical velocities is similar to published profiles with a preferred lithosphere thickness of 100 km. Tests with a different loading model (ICE-7G) and without hydrological corrections give similar results. Despite the exhaustive exploration of a constrained parameter space, the significant remaining horizontal residuals (RMS of the preferred model is 0.56 mm/yr, RMS of horizontal observations is 1.24 mm/yr) suggests the need for more complex Earth models.

APPROXIMATE METHODS OF RECOVERING THE ANGULAR VELOCITY OF PROJECTILE ROTATION ACCORDING TO DATA OF REFERENCE POINTS

A promising direction for determining individual aerodynamic force coefficients (moments) of a projectile is an approach based on solving the inverse problem of projectile motion dynamics based on experimental data of ballistic firing. In a number of works, the author obtained expressions for calculating the aerodynamic coefficients of the projectile, which functionally depends on the parameters obtained from external trajectory measurements and the angular velocity of the projectile. In addition, the accuracy of determining the aerodynamic coefficients is significantly affected by the change in the angular velocity of the projectile along its entire flight path. In the article, to obtain values of the angular velocity of rotation of the projectile, it is proposed to use a set of reference (pre-reference) points corresponding to the moment of departure from the barrel of the gun at different initial velocities of its flight. Numerical modeling was carried out and the accuracy of the calculation of the angular velocity of rotation of the projectile at reference (pre-reference) points was evaluated using the example of the 155-mm high- explosive fragmentation projectile Assegai M2000. It has been proven that with a relatively small number of shots at different initial speeds of the projectile flight, it is possible to obtain the value of its angular velocity of rotation at reference (pre- reference) points with the average value of the relative error, which is within -(0.01-0.03)%. Procedures for approximating the angular velocity of projectile rotation based on reference (pre-reference) points, as well as procedures for minimizing the error of their approximation, have been developed. It is shown that the obtained approximation functions ensure the passage of their curve through the given extreme reference (pre-reference) points and allow to minimize the errors in the calculation of the angular speed of rotation of the projectile, over the entire trajectory of its flight, in the range of - (0.08-0.3)%.

Three-dimensional flow structures modelling based on a depth-integrated method in a sharply curved open channel over topography

In this study, we introduce the bottom velocity calculation (BVC) technique, a depth-integrated approach for modeling three-dimensional flow systems in the two-dimensional (2D) river management model framework. The method has been expanded to a general coordinate system and its applicability to flow in bends and meanders for the applications to rivers. The method was validated to a laboratory experiment conducted in a sharply curved channel over topography. The pattern of water surface elevation and vertical velocity distribution can be replicated by the BVC method’s models, which also show strong qualitative agreement with the experimental dataset and 3D model. The benefit of using the BVC technique instead of the 2D model is verified; the 2D model is unable to replicate the profile since it does not take into account three-dimensional flow structures. As seen above, the BVC method is helpful in evaluating the river environment because it can account for the complicated material transports caused by three-dimensional flows in the meandering sections of the river channel.

Research on an effective method to improve the accuracy of sound velocity calculation in oil well casing

Research on an effective method to improve the accuracy of sound velocity calculation in oil well casing

Theoretical Foundations of the Physical-Mathematical Model of the Non-Stationary Combustion Process of Solid Fuel and Derivation of Methods for the Calculation of Non-Stationary Velocity

Theoretical Foundations of the Physical-Mathematical Model of the Non-Stationary Combustion Process of Solid Fuel and Derivation of Methods for the Calculation of Non-Stationary Velocity

A Comparative Performance Evaluation of Mainstream Multiphase Models for Aerated Flow on Stepped Spillways

A systematic comparative evaluation of mainstream multiphase models for specific hydraulic structures is essential to investigate aerated flow characteristics and promote the models’ application. However, such evaluations remain scarce. In this paper, four multiphase models, namely the VOF, Mixture, and Eulerian models in Ansys Fluent and the aerated flow model in FLOW-3D (AFM-F3D), were comparatively introduced and tested for the aerated flow over stepped spillways. Simulation results, including water surface profiles, inception points of aeration, air concentrations, velocities, and turbulent kinetic energies from four models, are compared with each other and with available experimental data. It is discovered that both the VOF and Mixture models fail to reproduce the self-aeration and subsequent downward transport phenomenon. In contrast, AFM-F3D and the Eulerian models predict reliable aerated water surface profiles. AFM-F3D and the Eulerian model demonstrate superior performance in velocity and air concentration calculations, respectively. Based on overall performance, the Eulerian model is recommended for simulating aerated stepped spillway flows. These insights provide valuable guidance for selecting appropriate multiphase models based on specific engineering requirements.

Research on the Construction of Coal Powder Settling Final Velocity Model for Coalbed Methane Wells in Panhe Block

ABSTRACTIn response to the severe problem of coal powder production in the Panhe block coalbed methane wells in the southern Qinshui Basin, the characteristics of coal powder production in the study area were identified through sample testing, indoor experiments, and theoretical calculations. The settling velocity of coal powder with different mesh sizes was clarified, and a correction factor α was proposed for the experimental and theoretical results of settling velocity. The research results indicate that the coal powder concentration in the Panhe block ranges from 0.03 to 7.14 g/L, with an average of 1.26 g/L. The particle size of the coal powder produced was 4.10–237.64 μm, with an average of 35.82 μm. The settling velocity of coal powder particles with a mesh size of 40–400 is between 0.0041 and 0.029 m/s. The larger the particle size of coal powder particles, the higher the settling velocity of coal powder; the correction coefficient ranges from 2.3 to 13.67. A corrected settling velocity calculation model was obtained by fitting the coal powder particle size data to the correction coefficient. The research results provide a theoretical basis for developing production conditions, coal powder prevention, and control measures for coalbed methane wells in the Panhe area.

Algorithm for predicting water quality indicators in water bodies using a neural network

Clean and safe drinking water is a fundamental necessity for human health and well-being and a critical component in sustainable ecosystem development. In recent decades, water quality issues have become even more urgent due to population growth, industrial expansion and climate change. A series of works by foreign researchers report results obtained by applying neural networks. There are studies confirming results of water quality prediction generated by neural networks to be quite valid. In this research, we used Google Earth Pro, Microsoft Excel, water flow sensor based on Arduino UNO board with author's modification (tail feathering and built-in plugin for calculation of flow velocity), Python, Tensorflows keras2.2.0, Scikit-learn, Pandas libraries for machine learning and development of neural network architecture. In this study, two ANNs were combined to build a hybrid neural network model for predicting water quality indicators. Neural network models offer unique opportunities to improve water resources management at various levels, ranging from local to global one. A key advantage of such models is a possibility to adapt them to specific conditions and requirements, which provides more accurate prediction and timely decision making under uncertainty. The relevance of the work is determined by application of neural networks for water quality prediction. This can improve systems for early warning about pollution, help optimize operational processes at water treatment plants and develop effective water management strategies. In this research, an innovative hybrid neural network model has been developed for predicting water quality indicators. It is based on integrating deep convolutional neural network and bidirectional recurrent neural network, which consists of three functional parts.

Визначення критичної швидкості пробиття мішеней зі сплавів алюмінію та магнію

The motion of a non-deformable kinetic projectile of cylindrical shape in a continuous homogeneous semi-infinite medium is considered based on the well-known Alekseevsky-Tate model. As a result of solving the differential equation of motion of the impactor, the dependence of its speed on the penetration depth was obtained. The boundary conditions are: before penetrating the target, the speed of the impactor is equal to the critical penetration speed, and after penetrating the thickness of the target, the speed of the impactor is equal to zero. A simple formula for calculating the critical velocity of target penetration Vcr is obtained based on this dependence. This formula does not contain empirical coefficients. Therefore, the calculation of Vcr requires a minimum of information about both the material of the projectile and the target. An improved equation for calculating the resistance of the target material is also proposed. For targets from aluminum and magnesium alloys, critical penetration rates depending on their thickness were theoretically calculated and penetration curves were plotted. Also, the critical penetration velocity for targets from these alloys was determined experimentally during ballistic tests the results of the authors' own research and taken from the literature. A good agreement between the experimental data and theoretical calculations of the critical penetration velocity is observed, with the calculation error not exceeding 4%. With regard to the assessment of the critical thickness of the target, the maximum error will be about 5%, the average – 2,5%. It is assumed that in order to provide the reliable guaranteed protection against a known projectile, it is necessary to overestimate by 4% the calculated value of the critical penetration velocity while designing the protective element. Keywords: equation of motion, impactor, target, critical velocity, aluminum alloys, magnesium alloys.

Strategy for Calculating the Speed of Trans Media Small Targets Using Stereo Vision Fusion Object Detection

Abstract The velocity calculation of the projectile entering water involves fluid dynamics, shock wave propagation and other aspects of the problem. Traditional photoelectric, radar and laser velocimeters suffer from reduced accuracy due to trans-media effects. At the same time, the projectile entering the water will create a large splash, which affects the parameter measurement of the projectile entering water. In order to address the above problems, a trans-media projectile entry system is constructed, a binocular high-speed camera is used to capture the dynamic process of the projectile entering the water, and a deep learning model is trained for the detection of the projectile target, which assists in the computation of the projectile’s three-dimensional coordinates and then. calculates the speed of the projectile at the moment it enters the water. The experimental results show that the binocular camera provides a better reconstruction of the 3D coordinates of the projectile, and the target detection combined with edge detection makes it easier to obtain the contour information as well as the pixel coordinates of the projectile. The mAP0.5 of the target detection model is 95.43%. Using this target detection model to extract useful images of projectile water entry frames from the video stream saves more than 90% of the time compared with manual extraction, providing an efficient calculation for calculating the velocity of trans media small targets.

Initial velocity circumferential distribution model of Multi-layer spherical premade fragments

Abstract To calculate the force field of multi-layer spherical premade fragment warheads, a calculation model for the initial velocity of multi-layer spherical fragments is constructed. Based on the scattering process of multi-layered spherical fragments under explosive loading, the fragment driving process is divided into three stages: common motion, filler penetration, and fragment delamination. A multi-layer spherical fragment circumferential initial velocity calculation model was constructed by combining the Stanovich model and Gurney model, using the momentum theorem and energy conservation law. Conducting numerical simulations and pulse X-ray verification experiments on the explosive loading of fragment warheads under different levels of fragment layers, the numerical simulation and experimental results show that when the number of fragment layers is less than 4, the average velocity of each layer calculated by the model has an average error of less than 15% compared to the simulation and experiment, which can basically achieve prediction of the initial velocity and distribution of premade fragments scattered along the circumferential direction in each layer.

Modeling Acoustic Attenuation, Sound Velocity and Wave Propagation in Lithium‐Ion Batteries via a Transfer Matrix

AbstractA simple 1D transfer matrix model of a battery is introduced and parametrized using harvested individual cell components at 0 % and 100 % SoC. This model allows for the calculation of group velocity and attenuation. The results of the model show good agreement with measured values, highlighting increased attenuation and group velocity at the resonances. This emphasizes the importance of selecting a suitable interrogation frequency for ultrasound investigations in lithium‐ion batteries. The model accurately replicates the observed weakening of resonances with increasing SoC. Additionally, it provides the basis to fit US spectroscopy data in the future, enabling immediate determination of component thickness and the Young's modulus of individual components, along with aiding in the identification aging effects of the anode and cathode materials. The model can visualize wave propagation within the battery. At certain frequencies, standing waves form which could be used in high‐intensity ultrasound applications targeted at individual cell components.

MODVORTEx: computer vision-driven automation for magnetic domain wall velocity analysis

Abstract This paper presents Magneto Optic Domain Velocity Observation and Real-Time Extraction (MODVORTEx), a comprehensive software solution for automating domain wall (DW) velocity measurements in magnetic materials using magneto-optic Kerr effect microscopy. Building upon our previous work on bubble domain structures, we introduce a versatile graphical user interface (GUI) that accommodates arbitrary domain shapes and employs advanced computer vision techniques. The software provides different methods for DW detection and velocity calculation, catering to various domain structures of arbitrary shape. Our approach significantly reduces the time and effort required for data extraction, transforming a process that previously took days of manual work into a task completable within minutes. We provide the details of the algorithmic implementation which is organized into pre-processing, DW detection, displacement measurement, and velocity extraction. This tool is applicable to a wide range of scenarios, including bubble domain dynamics, Dzyaloshinskii–Moriya interaction studies in perpendicular magnetic anisotropy systems, current-driven DW motion in patterned strips etc. By providing both GUI and Application Programing Interface, our software offers flexibility for integration into existing measurement systems and adaptability for specific research needs. This automation promises to accelerate research in spintronics and magnetic materials, enabling more comprehensive and accurate studies of DW dynamics.

Optimal configuration design and attitude measurement method of redundant accelerometer for steering drilling tools

Abstract In order to improve the accuracy and reliability of attitude parameters measurement of the rotary steerable drilling tool, a slanting configuration method and measurement method of double accelerometer were proposed. The measurement equation of the redundant accelerometer in the drill coordinate system is established. According to the installation position of the accelerometer and sensitive direction, the trouble-free and uniaxial failure in both cases, in order to improve the component of gravity and angular velocity calculation precision as the objective, design measure performance evaluation indexes, the optimal configuration determines the redundant accelerometer. It uses the stability equation constraints gravity no trace adaptive Kalman filter algorithm, Accurate angular velocity measurement, the tool face Angle, and healthy inclination. Simulation and experimental results show that the optimal configuration of the redundant accelerometer is reasonable, and the attitude estimation algorithm is effective.

Analysis of the third class mechanism using the modeling method in the Mathcad software environment

Purpose. To carry out a kinematic analysis of a flat twelve-link hinged mechanism with three leading links, the basis of which is a structural group of links of the third class of the fourth order with rotational kinematic pairs, which is used in technological equipment. Methodology. The kinematic study of a flat complex mechanism of the third class with three leading links was performed using the mathematical modeling method in the Mathcad software environment. Findings. Using the method of mathematical modeling, the mechanism was presented in the form of free vectors built on its links, for which, taking into account the presence of three leading links, three vector contours were selected, which made it possible to draw up a system of vector equations of their closedness with further solving by a numerical method in the Mathcad software environment. The functions of the rotation angles of the mechanism links, their angular velocities and accelerations were obtained in analytical and graphical form depending on the rotation angle of the first driving crank of the mechanism, the calculation of the angular velocities and accelerations of all the driven links of the mechanism was performed. Originality. A sequence was developed and a kinematic study of a complex planar mechanism of the third class with three leading links was done, the basis of which is a structural group of links of the third class of the fourth order. Schematic modeling of the mechanism with three leading links was performed, a visualization schedule of its kinematic scheme was built, and a valid version of its assembly was obtained from many possible ones, for which the values of kinematic parameters of all its links were determined. Practical value. An analysis of the effect of the kinematic parameters of the three leading links of the third-class mechanism on the movement of the working body of the technological equipment was carried out. From the analysis of the obtained research results for the cycle of the mechanism the reason was found for the incomplete technological stoppage of the link, which should provide the working body of the machine for the required period of time. Recommendations of the elimination were made to identify the deficiency and proposals for the need to improve the drive of this equipment.

Laboratory work in physics "The study of uniformly accelerated motion without initial velocity" using a robotic kit LEGO MINDSTORMS EDUCATION EV3

The article presents an example of using a robotic kit at physics and informatics lessons — a laboratory work "The study of uniformly accelerated motion without initial velocity" using the LEGO MINDSTORMS EDUCATION EV3 kit. This work is intended for students in 9–10th grades when studying uniformly accelerated motion in a physics course. During the laboratory work, it is necessary to: assemble an experimental setup and create a program for the EV3 control module, which should record the time of movement of a ball along an inclined chute with output to the EV3 module screen; enter the obtained measurement results into a calculation table compiled in an electronic spreadsheet, into which formulas for automatic calculation of acceleration and instantaneous velocity of the ball are preliminarily entered. The laboratory work can be carried out both in a physics and an informatics lessons, and in an optional lesson, you can also conduct an integrated physics and informatics lesson. The use of robotic modeling introduces students to the modern process of conducting physical research (experiments), helps to increase students' interest in experimental work, develop their skills in using robots in research and motivation for engineering and technical creativity.

Role of Humic Substances in the (Bio)Degradation of Synthetic Polymers under Environmental Conditions

Information on the detection of the presence and potential for degradation of synthetic polymers (SPs) under various environmental conditions is of increasing interest and concern to a wide range of specialists. At this stage, there is a need to understand the relationship between the main participants in the processes of (bio)degradation of SPs in various ecosystems (reservoirs with fresh and sea water, soils, etc.), namely the polymers themselves, the cells of microorganisms (MOs) participating in their degradation, and humic substances (HSs). HSs constitute a macrocomponent of natural non-living organic matter of aquatic and soil ecosystems, formed and transformed in the processes of mineralization of bio-organic substances in environmental conditions. Analysis of the main mechanisms of their influence on each other and the effects produced that accelerate or inhibit polymer degradation can create the basis for scientifically based approaches to the most effective solution to the problem of degradation of SPs, including in the form of microplastics. This review is aimed at comparing various aspects of interactions of SPs, MOs, and HSs in laboratory experiments (in vitro) and environmental investigations (in situ) aimed at the biodegradation of polymers, as well as pollutants (antibiotics and pesticides) that they absorb. Comparative calculations of the degradation velocity of different SPs in different environments are presented. A special place in the analysis is given to the elemental chemical composition of HSs, which are most successfully involved in the biodegradation of SPs. In addition, the role of photo-oxidation and photoaging of polymers under the influence of the ultraviolet spectrum of solar radiation under environmental conditions on the (bio)degradation of SPs in the presence of HSs is discussed.

Improving the Spectral Resolution and Wavelength Scale of SDO/EVE MEGS-A Flare Observations

The Extreme ultraviolet Variability Experiment (EVE) is one of three instruments onboard the Solar Dynamics Observatory (SDO). This paper focuses on using the “A” channel on the Multiple EUV Grating Spectrographs (MEGS-A) on EVE, which measures wavelengths of 5 – 37 nm, to improve the wavelength scale accuracy and spectral resolution during solar flares. EVE’s least processed (Level 0B) data product is used to create updated wavelength scales that are shown, through this analysis, to make more precise spectral measurements compared to EVE Level 2 data. An X2.2 class flare that occurred on 15 February 2011, SOL2011-02-15T0156, was used to derive the pixel-to-wavelength scales. An improvement range of 5.21% to 11.35% was found in the emission line widths. In the future, these measurements can be used for improved Doppler velocity calculations of the accelerated plasma of various temperatures during solar flares.

Laboratory systems for detonation research

Decarbonizing global energy systems is among the most pertinent challenges in the climate crisis. Tightly tied to the economic prosperity of a nation and responsible for more than 75% of global emissions, decarbonization of the energy sector will require well-developed solutions. The emergence of detonation engines can reduce emissions in aviation and gas-fired power generation, with theoretical efficiencies 40% lower than conventional engines. These efficiencies have yet to be realized in practice, due to our lack of understanding of detonation propagation and its instabilities. This project aimed to develop the laboratory systems required to study detonations. To this end, a long rectangular channel was manufactured and outfitted with a gas handling system to inject a mixture, an ignition system, pressure transducers to capture the propagation characteristics, and an optical system enabling Schlieren photography. The gas handling system uses sonic nozzles, thus flow rate is a linear function of upstream line pressure. Each line contains a pressure transducer, microcontroller to process signals, LCD for pressure readout, and a regulator for adjustment of the line pressure. The ignition system uses an ignition box that steps up a 12 V supply to 400 V, an ignition coil raising the voltage to 15-40 kV, and a spark plug to ignite the mixture. Ignition, pressure transducer signal acquisition, and Schlieren photography are all synchronized using a NI-6356 DAQ with LabVIEW. The DAQs analog input ports receive readings from the pressure transducers along the channel, the timing of which and known distance between transducers allows for velocity calculations. The schlieren system utilizes the digital output channels to synchronize camera shutter with an LED driver, and parabolic mirrors, positioned to optimize schlieren imaging. The LED driver requires greater current than produced by the DAQ thus a current amplifier circuit is used to bridge the DAQ and driver.