Kinetic Energy Index Research Articles

Directly measuring the power-law exponent and kinetic energy of atmospheric turbulence using coherent Doppler wind lidar

Abstract. Atmospheric turbulence parameters, such as turbulent kinetic energy and dissipation rate, are of great significance in weather prediction, meteorological disasters, and forecasting. Due to the lack of ideal direct detection methods, traditional structure function methods are mainly based on Kolmogorov's assumption of local isotropic turbulence and the well-known -5/3 power law within the inertial subrange, which limits their application. Here, we propose a method for directly measuring atmospheric turbulence parameters using coherent Doppler wind lidar, which can directly obtain atmospheric turbulence parameters and vertical structural features, breaking the limitations of traditional methods. The first published spatiotemporal distribution map of the power-law exponent of the inertial subrange is provided in this study, which indicates the heterogeneity of atmospheric turbulence at different altitudes and also indicates that the power-law exponent at high altitudes does not fully comply with the -5/3 power law, proving the superiority of our method. We analyze the results under different weather conditions, indicating that the method still holds. The turbulent kinetic energy and power-law index obtained by this method are continuously compared with the results obtained with an ultrasonic anemometer for a month-long period. The results of the two have high consistency and correlation, verifying the accuracy and applicability of the proposed method. The proposed method has great significance in studying the vertical structural characteristics of atmospheric turbulence.

In vitro and in silico assessment of flow modulation after deploying the Contour Neurovascular System in intracranial aneurysm models

BackgroundThe novel Contour Neurovascular System (Contour) has been reported to be efficient and safe for the treatment of intracranial, wide-necked bifurcation aneurysms. Flow in the aneurysm and posterior cerebral arteries...

The impact of the COVID-19 pandemic on new and old kinetic energy of industry from the perspective of high-frequency electricity consumption: Evidence from Henan Province

With the normalization of the epidemic situation, China’s economy often disturbed by the pandemic. Both the old and new growth drivers have been affected by the epidemic, and their development trend has dropped significantly. However, the new growth drivers have shown good capacity for industrial recovery, driving the rapid and steady growth of the economy. Therefore, an effective, intelligent, precise, and adaptable monitoring method to new and old industry kinetic energy should be taken, which not only improve the level of macroeconomic analysis, but also supply solid support for enterprises and governments to make reasonable decisions. This research uses weekly electricity consumption statistics to monitor the impact of the COVID-19 pandemic on new and old kinetic energy of industry in Henan Province in 2020. To make the statistics of different weeks comparable, this research uses exponential smoothing and Multiple-seasonal decomposition of time series by locally weighted scatterplot smoothing (MSTL) to correct and decompose the statistics. The new kinetic energy index, the old kinetic energy index and the industry kinetic energy index of major industries are calculated based on the corrected and decomposed statistics. The results show that the new kinetic energy has rapidly adjusted the industry development model based on its own industry characteristics to promote economic recovery.

The effect of special exercises according to the relative speed in the development of some physical abilities and the achievement of men's 400-meter run

The aim of the researcher, through his research, is to: Prepare exercises especially according to The kinetic energy index in the effectiveness of the men's 400-meter run And identify the effect of special exercises according to Kinetic energy in developing some special physical abilities and achieving 400- meter running for men The researcher assumed that there are statistically significant differences between the pre and post-tests and in favour of the post-test for the experimental research sample. The researcher identified the research sample as runners in athletics for men, as the research sample included (8) runners. They were distributed randomly by drawing lots into two control and experimental groups, each group consisting of (4) runners, as the experimental group implemented Special exercises Prepared by the researcher, either the control group The same traditional approach was adopted and the researcher concluded that speed endurance training at various distances had a positive effect on the experimental group compared to the control group. He came out with recommendations from it that it is preferable to adopt the standardized exercises prepared by the researcher in training runners for all groups to develop the ability to withstand the particular speed in the 400 m event.

The impact of Tabata-style workouts on young runners' ability to sprint 200 meters with strength and speed, as measured by the kinetic energy index

The importance of the research is reflected in studying the effect of Tabata-style exercises for performance stages in the strength characteristic of speed and the achievement of 200 meters for runners under 20 years old. As for the research problem: by following up and informing the researchers of the exercises of runners under 20 years old, they noticed the large number of trainers’ reliance on commonly applied training methods and methods and their lack of use of modern training methods, including the Tabata method, which is one of the modern training methods that have occurred recently, in which high-intensity training is used and in a short time , and this is commensurate with the nature and characteristics of the game and thus improving performance under the conditions of extreme work and raising the physical and skill level of the runners, as it works to increase the excitement and suspense of the runners, and through the foregoing, the research problem can be summarized in the following question: Does the use of Tabata-style exercises for the performance stages have a positive effect on the strength characteristic of speed and the achievement of 200 meters for runners under 20 years old. The research aimed at: preparing Tabata-style exercises according to the kinetic energy index, as well as identifying the effect of Tabata-style exercises for performance stages on strength, speed, and completion of 200 meters for runners under 20 years old. The researchers used the experimental method in a one-group style to solve the research problem, and for the research community, the research community was identified with the runners of the 200-meter race under 20 years for the 2020-2021 sports season, numbering (6) players, and then processing the data using appropriate statistical means.

The impact of Gibala-style workouts on runners under 20 years old's 200-meter performance and speed endurance according to energy index

The importance of the research is reflected in the study of the effect of exercises in the Jibala style according to the kinetic energy index of the performance stages in endurance of speed and achievement of 200 meters for runners under 20 years. As for the research problem: by following up and informing the researchers of the exercises of runners under 20 years old, they noticed that most of the trainers rely on commonly applied training methods and methods and their lack of use of modern training methods, including the Jebala method, which is one of the modern training methods that have occurred recently and which uses training in a short time. This is consistent with the nature and characteristics of the game, thus improving performance under the conditions of extreme work and raising the physical level of the runners. It also increases the excitement and suspense of the runners. Through the above, the research problem can be summarized in the following question:Does the use of Gibala-style exercises according to the kinetic energy index of the performance stages have a positive effect on endurance of speed and achievement of 200 meters for runners under 20 years? The research aimed at: Preparing Gibala-style exercises according to the kinetic energy index for the 200-meter performance stages, as well as identifying the effect of Gibala-style exercises for the performance stages on the endurance of speed and completion of 200 meters for runners under 20 years.

Impacts of the Tropical Pacific–Indian Ocean Associated Mode on Madden–Julian Oscillation over the Maritime Continent in Boreal Winter

Based on the observation and reanalysis data, the relationship between the Madden–Julian Oscillation (MJO) over the Maritime Continent (MC) and the tropical Pacific–Indian Ocean associated mode was analyzed. The results showed that the MJO over the MC region (95°–150° E, 10° S–10° N) (referred to as the MC–MJO) possesses prominent interannual and interdecadal variations and seasonally “phase-locked” features. MC–MJO is strongest in the boreal winter and weakest in the boreal summer. Winter MC–MJO kinetic energy variation has significant relationships with the El Niño–Southern Oscillation (ENSO) in winter and the Indian Ocean Dipole (IOD) in autumn, but it correlates better with the tropical Pacific–Indian Ocean associated mode (PIOAM). The correlation coefficient between the winter MC–MJO kinetic energy index and the autumn PIOAM index is as high as −0.5. This means that when the positive (negative) autumn PIOAM anomaly strengthens, the MJO kinetic energy over the winter MC region weakens (strengthens). However, the correlation between the MC–MJO convection and PIOAM in winter is significantly weaker. The propagation of MJO over the Maritime Continent differs significantly in the contrast phases of PIOAM. During the positive phase of the PIOAM, the eastward propagation of the winter MJO kinetic energy always fails to move across the MC region and cannot enter the western Pacific. However, during the negative phase of the PIOAM, the anomalies of MJO kinetic energy over the MC is not significantly weakened, and MJO can propagate farther eastward and enter the western Pacific. It should be noted that MJO convection is more likely to extend to the western Pacific in the positive phases of PIOAM than in the negative phases. This is significant different with the propagation of the MJO kinetic energy.

Heat transfer augmentation in retrofitted corrugated plate heat exchanger

Corrugated plate heat exchangers (CPHEs) have been extensively adopted especially for systems that require high thermal efficiencies such as aerospace and gas turbine power plants. According to several factors (i.e. required heat duty), CPHEs can be optimized to meet the application requirements. However, the number of the required thermal plates (Np) could be very large (Np>40) which in turn would cause several disadvantages (i.e. sever flow maldistribution). Therefore, the present study aims to introduce an innovative modification that can boost the thermal performance of the basic CPHE which in turn would reduce the number of required plates for the same heat duty. The thermal performance of the modified CPHE has been numerically investigated by using Computational Fluid dynamics (CFD) software. The numerical data have been validated with experimental measurement from the literature. The impact of the new modification has been studied on Nusselt number (Nu), fanning friction factor (f), Stanton number (St), Turbulence kinetic energy (TKE), flow maldistribution, j factor, and quality index factor (JF). The result has been compared with previously reported data of the basic corrugated and flat PHEs. At the same mass flow rate, Nu, f, and TKE of the modified CPHE are respectively 1.3, 1.7, and 3.5 times greater than those of the basic CPHE. Moreover, JF data of the modified CPHE are 1.4, and 64 times greater than those of the basic corrugated and flat PHEs, respectively. In addition to the superior thermal performance, the present modification offers larger contact area between the plates which could boost the overall mechanical integrity of the heat exchanger. Thus, this modification could pave the way for CPHEs to be incorporated in new applications that require more compact and durable HEs. The heat transfer correlations of the modified CPHE have been developed.

Automated mitral valve vortex ring extraction from 4D-flow MRI.

PurposeTo present and validate a method for automated extraction and analysis of the temporal evolution of the mitral valve (MV) vortex ring from MR 4D‐flow data.MethodsThe proposed algorithm uses the divergence‐free part of the velocity vector field for Q criterion‐based identification and tracking of MV vortex ring core and region within the left ventricle (LV). The 4D‐flow data of 20 subjects (10 healthy controls, 10 patients with ischemic heart disease) were used to validate the algorithm against visual analysis as well as to assess the method’s sensitivity to manual LV segmentation. Quantitative MV vortex ring parameters were analyzed with respect to both their differences between healthy subjects and patients and their correlation with transmitral peak velocities.ResultsThe algorithm successfully extracted MV vortex rings throughout the entire cardiac cycle, which agreed substantially with visual analysis (Cohen’s kappa = 0.77). Furthermore, vortex cores and regions were robustly detected even if a static end‐diastolic LV segmentation mask was applied to all frames (Dice coefficients 0.82 ± 0.08 and 0.94 ± 0.02 for core and region, respectively). Early diastolic MV vortex ring vorticity, kinetic energy and circularity index differed significantly between healthy controls and patients. In contrast to vortex shape parameters, vorticity and kinetic energy correlated strongly with transmitral peak velocities.ConclusionAn automated method for temporal MV vortex ring extraction demonstrating robustness with respect to LV segmentation strategies is introduced. Quantitative vortex parameter analysis indicates importance of the MV vortex ring for LV diastolic (dys)function.

Analysis of Electricity Consumption and Kinetic Energy Index in Fujian

The growth situation of emerging industries and new kinetic energy can be reflected by improving the statistical system of the “three new” industries. New ideas for the study of the “three new” industries are provided by the statistical analysis based on power big data. This paper studied the power big data of 2,084 “new industry” enterprises in Fujian province from 2014 to 2018. The research is divided into “new industry” electricity consumption analysis and “new industry” kinetic energy index research. First, the analysis is made for development trend, proportion, seasonal trend, different region and industry’s electricity characteristics of the electricity consumption in new industries. Second, the indicator system of “new industry” in Fujian is constructed. The results showed that,” new industries” are booming in Fujian province, but the momentum for development has weakened in 2018.

A homogeneous payload specific performance index for robot manipulators based on the kinetic energy

Performance indices are extensively used in the optimization of robot structures. However, in the case of manipulators with mixed translational and rotational DOFs, traditional indices are not readily applicable due to the non-homogeneity of the Jacobian matrix. In this paper, special cases of generalized inertia ellipsoid, GIE, [1] and rms velocity norm [2] are used to define a payload specific performance index based on the transferred kinetic energy to the payload. The proposed kinetic energy index, KEI, is dimensionally homogeneous and is independent from the units. Moreover, this index is scale invariant and simultaneously considers both of the translational and rotational motions. A unit KEI indicates that a uniform kinetic energy is transferred to the payload for all the feasible joint velocities. For better representations, kinetic energy ellipsoids are drawn using a new vector form definition of the kinetic energy. A two-link manipulator and a 3-RRR robot are considered as case studies for evaluation of the proposed index. The kinetic energy ellipsoids and contours of KEI value are plotted over the entire workspace of the two robots. For a given payload with specified dynamic characteristics, KEI can be used to design an optimal structure of the manipulator such that a uniform kinetic energy is transferred to the payload.

Quantifying the influence of oscillatory flow disturbances on blood flow

Pulsatile blood flow is renowned for inducing localised flow disturbances that are characterised by significant oscillations. These flow disturbances are recognised to have a physiologic significance within the cardiovascular system, particularly with respect to their proatherogenic expression on endothelial cells. Flow disturbances also impart significant influence on the mechanics of cardiovascular flow and are formally shown in the present study to be coupled to the period-average behaviour of a pulsatile flow field, causing it to be misrepresented by its steady-equivalent; which is often used in models of atherogenesis and hence limits their reliability. It is demonstrated that a measure of the localised influence of flow disturbances on the period-average flow can be realised by the relative significance of their kinetic energy, which is quantified by the introduced Oscillatory Kinetic Energy Index (OKEI). A specific measure of direction-reversing oscillations is also developed with the introduction of the Oscillatory Flow Index (OFI), which is an extension of the wall-bound Oscillatory Shear Index (OSI) onto flow and wall spaces. A case study of a human carotid artery is made; wherein pulsatile flow is studied relative to its steady-equivalent state. The introduced indices are demonstrated to collectively identify oscillatory flow disturbances within the flow; quantifying their spatial distribution and influence on the flow field.

Vector flow mapping analysis of left ventricular energetic performance in healthy adult volunteers

BackgroundVector flow mapping, a novel flow visualization echocardiographic technology, is increasing in popularity. Energy loss reference values for children have been established using vector flow mapping, but those for adults have not yet been provided. We aimed to establish reference values in healthy adults for energy loss, kinetic energy in the left ventricular outflow tract, and the energetic performance index (defined as the ratio of kinetic energy to energy loss over one cardiac cycle).MethodsTransthoracic echocardiography was performed in fifty healthy volunteers, and the stored images were analyzed to calculate energy loss, kinetic energy, and energetic performance index and obtain ranges of reference values for these.ResultsMean energy loss over one cardiac cycle ranged from 10.1 to 59.1 mW/m (mean ± SD, 27.53 ± 13.46 mW/m), with a reference range of 10.32 ~ 58.63 mW/m. Mean systolic energy loss ranged from 8.5 to 80.1 (23.52 ± 14.53) mW/m, with a reference range of 8.86 ~ 77.30 mW/m. Mean diastolic energy loss ranged from 7.9 to 86 (30.41 ± 16.93) mW/m, with a reference range of 8.31 ~ 80.36 mW/m. Mean kinetic energy in the left ventricular outflow tract over one cardiac cycle ranged from 200 to 851.6 (449.74 ± 177.51) mW/m with a reference range of 203.16 ~ 833.15 mW/m. The energetic performance index ranged from 5.3 to 37.6 (18.48 ± 7.74), with a reference range of 5.80 ~ 36.67.ConclusionsEnergy loss, kinetic energy, and energetic performance index reference values were defined using vector flow mapping. These reference values enable the assessment of various cardiac conditions in any clinical situation.

Characterisation of pattern formation in constrained multiblock assembly subjected to horizontal harmonic excitation

Pattern formation for a constrained one-dimensional assembly comprising a number of blocks undergoing external harmonic excitation of the basin boundary is investigated. The importance of the relationship between the excitation amplitude and the basin size which leads to repeatable response patterns of the single and multiple blocks is established, considering in addition the role of the energy dissipation due to inter block collisions and collisions with the moving boundary. Experimental results for the four- and eight-block assembly control problems, exposed to a range of amplitudes and frequencies, are included and compared with the two sets of computational simulation frameworks, the explicit discrete element method and the non-smooth contact dynamics. In the characterisation of the dynamic sensitivity response of the multiblock assemblies, several attributes and indices (kinetic energy index, block assembly mass centroid and mass inertia index, presented through time histories and phase planes) are extracted from both the experimental and computational simulation results and successfully compared.

Effects of turbulence enhancement on combustion process using a double injection strategy in direct-injection spark-ignition (DISI) gasoline engines

Direct-injection spark-ignition (DISI) gasoline engines have been spotlighted due to their high thermal efficiency. Increase in the compression ratio that result from the heat absorption effect of fuel vaporization induces higher thermal efficiency than found in port fuel injection (PFI) engines. Since fuel is injected at the cylinder directly, various fuel injection strategies can be used. In this study, turbulent intensity was improved by a double injection strategy while maintaining mixture homogeneity. To analyze the turbulence enhancement effects using the double injection strategy, a side fuel injected, homogeneous-charge-type DISI gasoline engine with a multi-hole-type injector was utilized. The spray model was evaluated using experimental data for various injection pressures and the combustion model was evaluated for varied ignition timing. First and second injection timing was swept by 20degree interval. The turbulent kinetic energy and mixture inhomogeneity index were mapped. First injection at the middle of the intake stroke and second injection early in the compression stroke showed improved turbulent characteristics that did not significantly decrease with mixture homogeneity. A double injection case that showed improved turbulent intensity while maintaining an adequate level of mixture homogeneity and another double injection case that showed significantly improved turbulent intensity with a remarkable decrease in mixture homogeneity were considered for combustion simulation. We found that the improved turbulent intensity increased the flame propagation speed. Also, the mixture homogeneity affected the pressure rise rate.

Calculation of Cardiac Kinetic Energy Index from PET images.

Cardiac function can be assessed from displacement measurements in imaging modalities from nuclear medicine Using positron emission tomography (PET) image sequences with Rubidium-82, we propose and estimate the total Kinetic Energy Index (KEf) obtained from the velocity field, which was calculated using 3D optical flow(OF) methods applied over the temporal image sequence. However, it was found that the brightness of the image varied unexpectedly between frames, violating the constant brightness assumption of the OF method and causing large errors in estimating the velocity field. Therefore total brightness was equalized across image frames and the adjusted configuration tested with rest perfusion images acquired from individuals with normal (n=30) and low (n=33) cardiac function. For these images KEf was calculated as 0.5731±0.0899 and 0.3812±0.1146 for individuals with normal and low cardiac function respectively. The ability of KEf to properly classify patients into the two groups was tested with a ROC analysis, with area under the curve estimated as 0.906. To our knowledge this is the first time that KEf has been applied to PET images.

Diastolic suction in heart failure: Impact of left ventricular geometry, untwist, and flow mechanics

AimsVector flow mapping (VFM) can be used to assess intraventricular hemodynamics quantitatively. This study assessed the magnitude of the suction flow kinetic energy with VFM and investigated the relation between left ventricular (LV) function and geometry in patients with an estimated elevated LV filling pressure. Materials and methodsWe studied 24 subjects with an elevated LV filling pressure (EFP group) and 36 normal subjects (normal group). Suction was defined as flow directed toward the apex during the period from soon after systolic ejection to before mitral inflow. The flow kinetic energy index was quantified as the sum of the product of the blood mass and velocity vector and its magnitude to the peak value was measured. Key findingsSuction flow was observed in 12 (50%) EFP-group patients and 36 (100%) normal-group subjects. The magnitude of the suction kinetic energy index was significantly smaller in EFP versus normal group (2.7±3.8 vs. 5.7±4.4g/s/cm2, P<0.01). The EFP-group patients with suction had a smaller LV end-systolic volume (ESV) (P<0.01), greater ellipsoidal geometry (P<0.05) and untwisting rate (P<0.01) than the EFP-group patients without suction. A regression analysis indicated a significant linear relation between the suction kinetic energy index and LVEF (r=0.43, P=0.04), ESV (r=−0.40, P=0.05), eccentricity index (r=0.44, P=0.04), and untwisting rate (r=0.51, P=0.04). SignificanceThe magnitude of the suction flow kinetic energy index derived from VFM may allow the quantitative assessment of the suction flow, which correlates with LV systolic function, geometry, and untwisting mechanics.

Deriving electromagnetic radial diffusion coefficients of radiation belt equatorial particles for different levels of magnetic activity based on magnetic field measurements at geostationary orbit

In this paper, we show that the correlation that exists between magnetic variations and induced electric fields through Faraday's law is of prime importance for adequately characterizing electromagnetic radial diffusion. Accordingly, we present an approach to derive electromagnetic radial diffusion coefficients based on magnetic field measurements at geostationary orbit. It consists of setting a very simple theoretical electromagnetic field model, considering the magnetic field as a background dipolar field on which two small time disturbances are superimposed: a symmetric disturbance and an asymmetric disturbance. Within this framework, electromagnetic radial diffusion is quantified analytically, taking into account both induced electric and magnetic contributions. The role played by the time variations of the field asymmetry is highlighted. From this, we deduce instantaneous field asymmetries from measurements of the magnetic field at the same time in two different places of the geostationary orbit. Then, we perform a statistical analysis of the time variations of this signal based on more than 7 years of data from the NOAA‐GOES 8, NOAA‐GOES 10, and NOAA‐GOES 12 spacecraft, working with time resolutions of 1 and 5 min. We show that the asymmetry signal is not stationary, having time‐dependent statistical properties, and we question accordingly the standard formulation of the electromagnetic radial diffusion coefficient and the role of drift‐resonant interactions. Finally, we provide new electromagnetic radial diffusion coefficients at geostationary orbit as a function of electron kinetic energy and Kp index from 0 to 4.

Abnormal early diastolic intraventricular flow 'kinetic energy index' assessed by vector flow mapping in patients with elevated filling pressure

Recently developed vector flow mapping (VFM) enables evaluation of local flow dynamics without angle dependency. This study used VFM to evaluate quantitatively the index of intraventricular haemodynamic kinetic energy in patients with left ventricular (LV) diastolic dysfunction and to compare those with normal subjects. We studied 25 patients with estimated high left atrial (LA) pressure (pseudonormal: PN group) and 36 normal subjects (control group). Left ventricle was divided into basal, mid, and apical segments. Intraventricular haemodynamic energy was evaluated in the dimension of speed, and it was defined as the kinetic energy index. We calculated this index and created time-energy index curves. The time interval from electrocardiogram (ECG) R wave to peak index was measured, and time differences of the peak index between basal and other segments were defined as ΔT-mid and ΔT-apex. In both groups, early diastolic peak kinetic energy index in mid and apical segments was significantly lower than that in the basal segment. Time to peak index did not differ in apex, mid, and basal segments in the control group but was significantly longer in the apex than that in the basal segment in the PN group. ΔT-mid and ΔT-apex were significantly larger in the PN group than the control group. Multiple regression analysis showed sphericity index, E/E' to be significant independent variables determining ΔT apex. Retarded apical kinetic energy fluid dynamics were detected using VFM and were closely associated with LV spherical remodelling in patients with high LA pressure.

Statistical analysis of pitch angle distribution of radiation belt energetic electrons near the geostationary orbit: CRRES observations

[1] A statistical analysis of energetic radiation belt electron pitch angle distributions (PADs) at the radial distances of 6 RE and 6.6 RE is performed on the basis of the pitch angle resolved flux observations from the Medium Electrons A (MEA) instrument onboard the Combined Release and Radiation Effects Satellite (CRRES). While previous studies of Vampola (1998) and Gannon et al. (2007) have used CRRES MEA data to investigate the general variations in electron PAD at particular energies, in this study we present a detailed statistical analysis of electron PADs including the dependence on electron kinetic energy, magnetic local time (MLT), and the level of geomagnetic activity. By fitting the measured PADs with a power law function of sine of local pitch angle, the power law index n that relates to the category of radiation belt electron PAD is quantified in detail as a function of electron kinetic energy, MLT interval, and geomagnetic index Kp. Statistical averaged n values vary considerably with respect to MLT, ranging from n ∼ 0 within 0000–0400 MLT to n ∼ 1.5 within 1200–1600 MLT, because of the MLT dependence of wave scattering and the effects associated with drift shell splitting and magnetopause shadowing. Drift shell splitting and magnetopause shadowing result in often observed negative values of n. At lower energies of a few hundred keV the pitch angle distributions are more flat than at MeV energies, which is consistent with faster pitch angle scattering at low energies by chorus waves. These quantitative results of radiation belt electron PAD, consistent with the previous studies by Vampola (1998) and Gannon et al. (2007), provide further insight into the global dynamics of energetic radiation belt electrons near the geostationary orbit and also are useful for inferring electron phase space densities and assimilating their radial profiles using omnidirectional electron flux measurements.