Kinetic Energy Parameters Research Articles

Longitudinal Changes in Left Ventricular Blood Flow Kinetic Energy After Myocardial Infarction: Predictive Relevance for Cardiac Remodeling.

Four-dimensional (4D) flow cardiac magnetic resonance (cardiac MR) imaging provides quantification of intracavity left ventricular (LV) flow kinetic energy (KE) parameters in three dimensions. ST-elevation myocardial infarction (STEMI) patients have been shown to have altered intracardiac blood flow compared to controls; however, how 4D flow parameters change over time has not been explored previously. Measure longitudinal changes in intraventricular flow post-STEMI and ascertain its predictive relevance of long-term cardiac remodeling. Prospective. Thirty-five STEMI patients (M:F = 26:9, aged 56 ± 9 years). A 3 T/3D EPI-based, fast field echo (FFE) free-breathing 4D-flow sequence with retrospective cardiac gating. Serial imaging at 3-7 days (V1), 3-months (V2), and 12-months (V3) post-STEMI, including the following protocol: functional imaging for measuring volumes and 4D-flow for calculating parameters including systolic and peakE-wave LVKE, normalized to end-diastolic volume (iEDV) and stroke volume (iSV). Data were analyzed by H.B. (3 years experience). Patients were categorized into two groups: preserved ejection fraction (pEF, if EF > 50%) and reduced EF (rEF, if EF < 50%). Independent sample t-tests were used to detect the statistical significance between any two cohorts. P < 0.05 was considered statistically significant. Across the cohort, systolic KEisv was highest at V1 (28.0 ± 4.4μJ/mL). Patients with rEF retained significantly higher systolic KEisv than patients with pEF at V2 (18.2 ± 3.4μJ/mL vs. 6.9 ± 0.6μJ/mL, P < 0.001) and V3 (21.6 ± 5.1μJ/mL vs. 7.4 ± 0.9μJ/mL, P < 0.001). Patients with pEF had significantly higher peakE-wave KEiEDV than rEF patients throughout the study (V1: 25.4 ± 11.6μJ/mL vs. 18.1 ± 9.9μJ/mL, P < 0.03, V2: 24.0 ± 10.2μJ/mL vs. 17.2 ± 12.2μJ/mL, P < 0.05, V3: 27.7 ± 14.8μJ/mL vs. 15.8 ± 7.6μJ/mL, P < 0.04). Systolic KE increased acutely following MI; in patients with pEF, this decreased over 12months, while patients with rEF, this remained raised. Compared to patients with pEF, persistently lower peakE-wave KE in rEF patients is suggestive of early and fixed impairment in diastolic function. 1 TECHNICAL EFFICACY: Stage 3.

Ab Initio Study of the Large Amplitude Motions of Various Monosubstituted Isotopologues of Methylamine (CH3-NH2)

CCSD(T)-F12 theory is applied to determine electronic ground state spectroscopic parameters of various isotopologues of methylamine (CH3-NH2) containing cosmological abundant elements, such as D, 13C and 15N. Special attention is given to the far infrared region. The studied isotopologues can be classified in the G12, G6 and G4 molecular symmetry groups. The rotational and centrifugal distortion constants and the anharmonic fundamentals are determined using second order perturbation theory. Fermi displacements of the vibrational bands are predicted. The low vibrational energy levels corresponding to the large amplitude motions are determine variationally using a flexible three-dimensional model depending on the NH2 bending and wagging and the CH3 torsional coordinates. The model has been defined assuming that, in the amine group, the bending and the wagging modes interact strongly. The vibrational levels split into six components corresponding to the six minima of the potential energy surface. The accuracy of the kinetic energy parameters has an important effect on the energies. Strong interactions among the large amplitude motions are observed. Isotopic effects are relevant for the deuterated species.

Development a novel hexagonal airlift flat plate photobioreactor for the improvement of microalgae growth that simultaneously enhance CO2 bio-fixation and wastewater treatment

A novel hexagonal airlift flat plate (HAFP) photobioreactor was designed to improve microalgae growth rate and compared with traditional flat plate (TFP) photobioreactor. The computational fluid dynamics (CFD) simulation was used to determine hydrodynamic parameters and optimal aeration rate in the photobioreactors. Additionally, the capability of the HAFP photobioreactor to enhance microalgae based CO2 bio-fixation and wastewater treatment were investigated. The results of CFD simulation indicated that the HAFP photobioreactor could improve hydrodynamic parameters of turbulence kinetic energy (TKE), average fluid velocity, dead zone (DZ), and water shear stress (WSS) up to 78 %, 41 %, 44 % and 40 %, respectively, under optimal aeration rate of 0.6 vvm. The proposed HAFP photobioreactor showed a drastic improvement in microalgae growth (up to 61 %). The maximum CO2 removal of 53.8 % and bio-fixation of 0.85 g L−1 d−1 were achieved in the HAFP photobioreactor which were approximately 70 % more than that in the TFP photobioreactor. The results suggested that the HAFP photobioreactor could accelerate nutrients removal and achieve remarkably higher efficiencies of 91 %, 99 %, 97 % and 93 % of ammonia (NH3), nitrate (NO3−), phosphate (PO43−) and chemical oxygen demand (COD) within seven days of cultivation.

Impact of age, sex and ethnicity on intra-cardiac flow components and left ventricular kinetic energy derived from 4D flow CMR

BackgroundFour-dimensional flow cardiovascular magnetic resonance (4D flow CMR) allows quantification of left ventricular (LV) blood flow. We aimed to 1) establish reference ranges for 4D flow CMR-derived LV relative flow components and kinetic energy parameters indexed to end-diastolic volume (KEiEDV) among healthy Asian subjects, 2) assess effects of age and sex on these parameters, and 3) compare these parameters between Asian and Caucasian subjects. Methods74 healthy Asian subjects underwent cine and 4D flow CMR. Relative flow components (direct flow, retained inflow, delayed ejection flow, residual volume) and multiple phasic KEiEDV (LV global, peak systolic, systolic, diastolic, peak E-wave, peak A-wave) were analyzed. Sex- and age-specific reference ranges were reported. ResultsRelative flow components and systolic phase KEiEDV did not vary with age. Women had higher retained inflow and peak E-wave KEiEDV, lower residual volume, peak systolic and systolic KEiEDV than men. Peak A-wave KEiEDV increased significantly (r = 0.474) whereas peak E-wave KEiEDV (r = −0.458) and E-wave/A-wave ratio (r = −0.528) decreased with age. A sub-population (n = 44) was compared with 44 sex- and age-matched Caucasian subjects: no significant group differences were observed for all 4D flow CMR parameters. ConclusionAsian sex- and age-specific 4D flow CMR reference ranges were established. Sex differences in retained inflow, residual volume, peak systolic, systolic KEiEDV and peak E-wave KEiEDV were observed. Ageing influenced diastolic KEiEDV but not systolic phase KEiEDV or relative flow components. All studied parameters were similar between sex- and age-matched Asian and Caucasian subjects, implying generalizability of the ranges.

Left ventricular blood flow kinetic energy is associated with the six-minute walk test and left ventricular remodelling post valvular intervention in aortic stenosis.

Left ventricular (LV) kinetic energy (KE) assessment by four-dimensional flow cardiovascular magnetic resonance (4D flow CMR) may offer incremental value over routine assessment in aortic stenosis (AS). The main objective of this study is to investigate the LV KE in patients with AS before and after the valve intervention. In addition, this study aimed to investigate if LV KE offers incremental value for its association to the six-minute walk test (6MWT) or LV remodelling post-intervention. We recruited 18 patients with severe AS. All patients underwent transthoracic echocardiography for mean pressure gradient (mPG), CMR including 4D flow and 6MWT. Patients were invited for post-valve intervention follow-up CMR at 3 months and twelve patients returned for follow-up CMR. KE assessment of LV blood flow and the components (direct, delayed, retained and residual) were carried out for all cases. LV KE parameters were normalised to LV end-diastolic volume (LVEDV). For LV blood flow KE assessment, the metrics including time delay (TD) for peak E-wave from base to mid-ventricle (14±48 vs. 2.5±9.75 ms, P=0.04), direct (4.91±5.07 vs. 1.86±1.72 µJ, P=0.01) and delayed (2.46±3.13 vs. 1.38±1.15 µJ, P=0.03) components of LV blood flow demonstrated a significant change between pre- and post-valve intervention. Only LV KEiEDV (r=-0.53, P<0.01), diastolic KEiEDV (r=-0.53, P<0.01) and Ewave KEiEDV (r=-0.38, P=0.04) demonstrated association to the 6MWT. However, Pre-operative LV KEiEDV (r=0.67, P=0.02) demonstrated association to LV remodelling post valve intervention. LV blood flow KE is associated with 6MWT and LV remodelling in patients with AS. LV KE assessment provides incremental value over routine LV function and pressure gradient (PG) assessment in AS.

Quantification of Cardiac Kinetic Energy and Its Changes During Transmural Myocardial Infarction Assessed by Multi-Dimensional Seismocardiography.

Introduction: Seismocardiography (SCG) records cardiac and blood-induced motions transmitted to the chest surface as vibratory phenomena. Evidences demonstrate that acute myocardial ischemia (AMI) profoundly affects the SCG signals. Multidimensional SCG records cardiac vibrations in linear and rotational dimensions, and scalar parameters of kinetic energy can be computed. We speculate that AMI and revascularization profoundly modify cardiac kinetic energy as recorded by SCG.Methods: Under general anesthesia, 21 swine underwent 90 min of myocardial ischemia induced by percutaneous sub-occlusion of the proximal left anterior descending (LAD) coronary artery and subsequent revascularization. Invasive hemodynamic parameters were continuously recorded. SCG was recorded during baseline, immediately and 80 min after LAD sub-occlusion, and immediately and 60 min after LAD reperfusion. iK was automatically computed for each cardiac cycle (iKCC) in linear (iKLin) and rotational (iKRot) dimensions. iK was calculated as well during systole and diastole (iKSys and iKDia, respectively). Echocardiography was performed at baseline and after revascularization, and the left ventricle ejection fraction (LVEF) along with regional left ventricle (LV) wall abnormalities were evaluated.Results: Upon LAD sub-occlusion, 77% of STEMI and 24% of NSTEMI were observed. Compared to baseline, troponins increased from 13.0 (6.5; 21.3) ng/dl to 170.5 (102.5; 475.0) ng/dl, and LVEF dropped from 65.0 ± 0.0 to 30.6 ± 5.7% at the end of revascularization (both p < 0.0001). Regional LV wall abnormalities were observed as follows: anterior MI, 17.6% (three out of 17); septal MI, 5.8% (one out of 17); antero-septal MI, 47.1% (eight out of 17); and infero-septal MI, 29.4% (five out of 17). In the linear dimension, , , and dropped by 43, 52, and 53%, respectively (p < 0.0001, p < 0.0001, and p = 0.03, respectively) from baseline to the end of reperfusion. In the rotational dimension, and dropped by 30 and 36%, respectively (p = 0.0006 and p < 0.0001, respectively), but did not change (p = 0.41). All the hemodynamic parameters, except the pulmonary artery pulse pressure, were significantly correlated with the parameters of iK, except for the diastolic component.Conclusions: In this very context of experimental AMI with acute LV regional dysfunction and no concomitant AMI-related heart valve disease, linear and rotational iK parameters, in particular, systolic ones, provide reliable information on LV contractile dysfunction and its effects on the downstream circulation. Multidimensional SCG may provide information on the cardiac contractile status expressed in terms of iK during AMI and reperfusion. This automatic system may empower health care providers and patients to remotely monitor cardiovascular status in the near future.

Longitudinal change in left ventricular 4D flow kinetic energy after myocardial infarction

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): British Heart Foundation HRUK Background. Four-dimensional flow (4D flow) cardiovascular magnetic resonance (CMR) imaging provides quantification of intra-cavity left ventricular (LV) flow kinetic energy (KE) parameters in three dimensions. Myocardial infarction (MI) is known to cause acute alterations in intra-cardiac blood flow but assessments of longitudinal changes are lacking. Purpose. Assess longitudinal changes in LV flow post ST-elevation myocardial infarction (STEMI). Method. Twenty acutely reperfused STEMI patients (13 men, 7 women, mean age 54 ± 9 years) underwent 3T CMR acutely (within 5-7 days) and 3 months post-MI. CMR protocol included functional imaging, late gadolinium enhancement and 4D flow. Using Q-MASS, LV KE parameters were derived and indexed to LV end-diastolic volume (LVKEiEDV). Based on acute ejection fraction (EF), patients were grouped as follows: preserved (pEF) EF &amp;gt;50%, reduced (rEF) EF &amp;lt;50% including mild (rEF= 40-49%), moderate to severe (EF &amp;lt;40%) impairment. Results. Out of 20 patients, 13 had rEF acutely (7 mild rEF, 6 moderate to severe rEF). Acute LVKEiEDV parameters varied significantly between pEF and rEF (Table). At 3 months, pEF and mild rEF patients showed a significant (P &amp;lt; 0.05) reduction in average, systolic and peak-A wave LVKEiEDV. Mild rEF patients also had significant (P &amp;lt; 0.05) reduction in minimal and peak-E wave LVKEiEDV. However in patients with moderate to severe rEF in the acute scan, there were no significant change by 3 months (Figure). Conclusion. Following MI, 4D flow LVKE derived biomarkers significantly decreased over time in pEF and mild rEF groups but not in moderate to severe rEF group. 4D flow assessment might provide incremental prognostic value beyond EF assessment alone. Table pEF (n = 7) rEF (n = 13) V1 V2 P-value V1 V2 P-value EF(%) 56 ± 5 55 ± 4 0.40 41 ± 7 47 ± 9 0.01 Infarct Size(%) 31 ± 20 15 ± 9 0.04 18 ± 13† 16 ± 11 0.41 LV KEiEDV parameters Average(µJ/ml) 9 ± 2 7 ± 2 0.02 10 ± 3† 8 ± 3 0.01 Minimal(µJ/ml) 1 ± 0.6 1 ± 0.5 0.46 1.3 ± 0.5 1 ± 0.6 0.03 Systolic(µJ/ml) 10 ± 4 7 ± 2 &amp;lt;0.01 12 ± 4† 7 ± 3 &amp;lt;0.01 Diastolic(µJ/ml) 8 ± 3 7 ± 2 0.13 9 ± 3 8 ± 3 0.09 Peak-E wave(µJ/ml) 22 ± 9 23 ± 8 0.44 20 ± 7 18 ± 10 0.23 Peak-A wave(µJ/ml) 18 ± 10 11 ± 4 0.04 17 ± 9 14 ± 7 0.02 †P &amp;lt; 0.05 V1 comparison between pEF and rEF Abstract Figure

Human Locomotion Strategies Under Changed Bodyweight Support.

INTRODUCTION: The aim of this study was the analysis of human musculoskeletal system energy costs of normal walking and walking under reduced weight loading.METHODS: There were 15 subjects who participated in the study. We analyzed the biomechanical parameters of walking under different musculoskeletal system loads. The subjects walked on a treadmill at a pace of 90 steps/min under various loading conditions: 1) 100% bodyweight loading, corresponding to the terrestrial surface; 2) 38% bodyweight loading, corresponding to the surface of Mars; and 3) 17% bodyweight loading, corresponding to the surface of the Moon. Joint angles and angular velocities were recorded from the hip, knee, and ankle.RESULTS: We analyzed changes in joint phase trajectories and the ratio of kinetic extension energy to kinetic flexion energy in the joints. We observed changes in kinetic energy parameters associated with both flexion and extension motions in the joints of the feet while walking under various loads. In terrestrial conditions (walking under 100% bodyweight), flexion kinetic energy in the hip joint prevailed over extension kinetic energy by 90%, with a small variation equal to 22%. If weight loading decreased up to 17% (lunar conditions), the difference between flexion and extension kinetic energies diminished, and eventually reached only 9%. The ratio of flexion energy and extension energy in the ankle joint equalized under lower loading conditions. Thus, 38% bodyweight loading was sufficient for approximation of flexion and extension energy values.DISCUSSION: Our results revealed that phase trajectories shifted toward smaller joint angles and a decreased ratio between extension kinetic energy and flexion kinetic energy in the knee joint of all subjects. However, significant differences in the ratio of flexion and extension kinetic energy in the knee joint under bodyweight support were not found. The methods used for musculoskeletal system assessments that were proposed in our work can be used in clinical practice to evaluate the effectiveness of rehabilitation measures in a patients musculoskeletal system disorders.Shpakov AV, Artamonov AA, Voronov AV, Plotnikov EV, Puchkova AA, Orlov DO. Human locomotion strategies under changed bodyweight support. Aerosp Med Hum Perform. 2021; 92(1):410.

Indian summer monsoon features in the NCEP analysis and forecast system

The diagnosis of the summer monsoon features over India are investigated using global analysis and forecast system (GFS) of the National Center for Environmental Prediction (NCEP). In addition, the performance of the NCEP GFS model in capturing the observed rainfall variability of the summer monsoon features over India through diagnostic parameters. We delineate the variability between two normal monsoon seasons with basic meteorological fields and significant parameters of kinetic energy, heat and moisture budgets. The 1200 UTC operational analyses and forecasts (day1 through day5) data for summer monsoon seasons of June, July, August and September (JJAS) of 2010 and 2011 are considered. Although both are normal monsoon seasons with seasonal rainfall (JJAS) departure of about −3.1% and 2.1% respectively, during 2010 and 2011, some differences are observed in the spatial distribution of rainfall. The diagnostic fields reasonably reproduced the variations in analyses and forecast fields of up to 5 days. The model forecasts of day1 delineated that the Indian summer monsoon features are well captured, whereas in day3 and day5, forecast depicts some differences. Overall the NCEP analysis and forecast fields not only produces mean monsoonal flow, but also captures seasonal variability realistically. This is evident from the large-scale balances represented by the analyses and model forecasts.

Improved analytical energy balance model for evaluating agglomeration from a binary collision of identical wet particles

Particle agglomeration is a common phenomenon in a large number of industries. The presence of a liquid bridge between colliding wet particles is the principal source of agglomeration in such processes as wet granulation and thermal conversion of fuels in a high temperature gas–solid fluidized bed reactor. A comprehensive agglomeration model for wet particles must incorporate both liquid capillary and viscous contributions, as well as the liquid bridge volume effect. Darabi et al. (Chem. Eng. Sci. 64 (2009) 1868–1876) developed a coalescence model for a binary collision of identical wet particles. The model provides reasonable results for wet particles with a low viscosity liquid layer, i.e., under capillary limiting conditions. However, application of this model for collisions of particles coated with a high viscosity liquid layer, i.e., under viscous limiting conditions, results in unreliable outcomes. The current study presents an improved version of Darabi et al.’s model, which (i) corrects viscous energy loss equations in the original model, thus providing reasonable outcomes under both capillary and viscous limiting conditions with highly wetting systems, (ii) accounts for the contribution of capillary force in the approach stage when estimating the initial particle speed for the separation stage, (iii) accounts for the collision of particles having different initial speeds with respect to the laboratory reference frame, (iv) employs a more reliable correlation to estimate the liquid bridge rupture distance, and (v) evaluates the collision outcome in three steps based on the values of kinetic energy parameters. We compared experimental particle-plate collision data with the predictions from agglomeration models and it showed that considering the liquid bridge volume effect and the liquid bridge rupture distance can be essential for the accurate prediction of collision outcomes. The results of sensitivity analyses with the improved agglomeration model revealed that the agglomeration outcome under capillary limiting conditions is most sensitive to the thickness of the coating layer, particle inertia, liquid surface tension, and dry restitution coefficient. Under viscous limiting conditions, proper measurement or estimation of the thickness of the coating layer, liquid viscosity, asperity height, and particle inertia are critical for evaluating the particle collision outcome.

The change of rainfall kinetic energy content with altitude

Erosion is the process of land degradation due to rainfall and other environmental factors, and it can be described by indices such as the kinetic energy of rainfall (KE). Microphysical data from disdrometers have been used to determine the relationship between kinetic energy content (KEmm, in J m−2 mm−1) and rainfall intensity (R, in mm h−1). Optical disdrometer (PWS100) measurements were gathered between 2014 and 2018 at five sampling sites across Mexico, and the data analyzed to study the characteristics of KEmm–R relationships with altitude. A PWS100 unit at each of the sampling sites was collocated a few meters from a tipping-bucket rain gauge to record R simultaneously. Individual raindrops fall speeds measured with the disdrometers were found to agree well with theoretical estimations using the environmental conditions at each sampling site. The mean fall velocities indicated that raindrops detected at the continental sampling sites (medium and high altitudes) have greater speeds than those near coastal areas (low altitudes). Comparisons of the estimated KEmm for rainy periods with comparable R show greater values as the altitude increases. This result is attributed to the increase of raindrop fall speed due to the air density decrement with altitude. Exponential relations between KEmm and R based on one-minute sampling periods were fitted for each sampling site, producing high values of coefficients of determination and suggesting a good response. Finally, the maximum kinetic energy parameter, KEmax, in the empirical KEmm–R equations was found to increase with altitude. These findings indicate that the detachment of soil particles by individual drops are magnified at higher altitude locations.

Impact of airflow on the heat transfer conditions inside an oven cavity, characterized using particle imaging velocimetry

The complex airflow in convection ovens directly influences the heat transferred to the product placed inside, thereby affecting product quality. Characterization of related airflow profiles can provide scientific understanding for improvement of oven designs as well as important parameters for simulation of involved thermal processes. In this study, the particle-imaging velocimetry (PIV) technique was applied to visualize airflow inside a household convection oven with samples placed at three different locations on a baking tray. The oven cavity was modified for optical access, and airflow was measured at room temperature. A 30 mW green laser was used for illuminating tracer particles in a laser sheet that were generated using incense sticks. The flow patterns were captured using a high-speed camera at 1000 fps. The vorticity and turbulent kinetic energy parameters derived from velocity fields reflected adequate mixing of air inside the cavity. The computed heat transfer coefficient distribution from the boundary layer flow fields to the sample surface ranged between 2.0 and 18.3 W m−2 K−1. The results showed separation of the laminar boundary layer from the object surface at angles of 85°–90°. The PIV-algorithms and boundary layer flow derived parameters developed in this study can be used for refined characterization of complex air or gas flows and related heat transfer characteristics in closed cavity convection ovens and the like arrangements.

Investigations of the kinetic energy parameters of irradiated (La)-doped phosphate glass.

The current study characterizes and analyzes glow curves obtained from phosphate glass doped with different concentrations of lanthanum. Kinetic parameters of the glow curves obtained from beta-irradiated phosphate glass samples doped with lanthanum were determined using a newly designed deconvoluted software. The obtained results from the analyses indicated that the glow curves of the phosphate glass samples were composed of five overlapping peaks. The activation energies of the five electron traps were located between 0.622 and 1.133eV. The obtained kinetic parameters were evaluated using the designed software and another two methods and all revealed good agreement. The first three traps displayed non-first-order behaviour, while the two deep traps obeyed nearly first-order kinetics.

Anomaly detection in group activities based on fuzzy lattices using Schrödinger equation

This paper proposes a new method to detect abnormality in a video captured for surveillance applications in real-time and also overcome the problem of the curse of dimensionality. To extract features related to any change in the video, nonlinear Gaussian fuzzy lattice functions have been applied on each frame of the video which results in the formation of fuzzy lattices. These fuzzy lattices have been expressed in the form of Schrodinger equation to find the kinetic energy involved corresponding to any change in the video. A number of the fuzzy lattice has been used as a dimension of the feature. It reduces the dimensionality significantly as compared to other state-of-the-art methods. Finally, the kinetic energy parameter is classified into normal and abnormal activities with the help of SVM-based classifier.

Evaluating and modelling splash detachment capacity based on laboratory experiments

Splash erosion is recognized as an important process of water erosion on agricultural land, but evaluating and modelling splash detachment capacity on steep slopes using loessial soil were not fully studied. The objectives of this study are: (1) to evaluate the effects of slope gradient (S) and rainfall intensity (I) on splash detachment capacity (SDr), (2) to select the key rainfall physical parameters and hydraulic parameters affecting splash detachment capacity, (3) to establish new and more accurate experimental models between splash detachment capacity (SDr) and these key parameters on steep slopes for loess regions. The experiment was conducted at slopes of 12.23%, 17.63%, 26.8%, 36.4%, 40.4% and 46.63% under rainfall intensities of 48, 60, 90, 120, 138 and 150 mm h−1, respectively, using simulated rainfall. Results showed that the equation between splash detachment capacity (SDr) with both parameters of rainfall intensity (I) and slope gradient (S) (i.e. SDr = 0.000126 ln (0.36S−0.3I1.3 − 14)) could predict SDr well with R2 = 0.85 and Nash–Sutcliffe model efficiency (NSE) = 0.71. SDr was more sensitive to rainfall intensity than to slope gradient. The rainfall kinetic energy (KE) was the key rainfall physical parameter and the mean flow depth (h) was the key hydraulic parameter affecting SDr. The equation between SDr with both parameters of KE and h (i.e. SDr = 0.000164 ln (0.0031KE1.13h−0.3 − 4.5)) could satisfactorily predict SDr with R2 = 0.85 and Nash–Sutcliffe model efficiency (NSE) = 0.81. The new equations (i.e. SDr = 0.000126 ln (0.36S−0.3I1.3 − 14) and SDr = 0.000164 ln (0.0031KE1.13h−0.3 − 4.5)) could help in controlling water erosion in the loess region of China.

Impact of Age and Diastolic Function on Novel, 4D flow CMR Biomarkers of Left Ventricular Blood Flow Kinetic Energy

Two-dimensional (2D) methods of assessing mitral inflow velocities are pre-load dependent, limiting their reliability for evaluating diastolic function. Left ventricular (LV) blood flow kinetic energy (KE) derived from four-dimensional flow cardiovascular magnetic resonance imaging (4D flow CMR) may offer improvements. It remains unclear whether 4D LV blood flow KE parameters are associated with physiological factors, such as age when compared to 2D mitral inflow velocities. Fifty-three healthy volunteers underwent standard CMR, plus 4D flow acquisition. LV blood flow KE parameters demonstrated good reproducibility with mean coefficient of variation of 6 ± 2% and an accuracy of 99% with a precision of 97%. The LV blood flow KEiEDV E/A ratio demonstrated good association to the 2D mitral inflow E/A ratio (r = 0.77, P < 0.01), with both decreasing progressively with advancing age (P < 0.01). Furthermore, peak E-wave KEiEDV and A-wave KEiEDV displayed a stronger association to age than the corresponding 2D metrics, peak E-wave and A-wave velocity (r = −0.51 vs −0.17 and r = 0.65 vs 0.46). Peak E-wave KEiEDV decreases whilst peak A-wave KEiEDV increases with advancing age. This study presents values for various LV blood flow KE parameters in health, as well as demonstrating that they show stronger and independent correlations to age than standard diastolic metrics.

Left ventricular blood flow kinetic energy after myocardial infarction - insights from 4D flow cardiovascular magnetic resonance

BackgroundMyocardial infarction (MI) leads to complex changes in left ventricular (LV) haemodynamics that are linked to clinical outcomes. We hypothesize that LV blood flow kinetic energy (KE) is altered in MI and is associated with LV function and infarct characteristics. This study aimed to investigate the intra-cavity LV blood flow KE in controls and MI patients, using cardiovascular magnetic resonance (CMR) four-dimensional (4D) flow assessment.MethodsForty-eight patients with MI (acute-22; chronic-26) and 20 age/gender-matched healthy controls underwent CMR which included cines and whole-heart 4D flow. Patients also received late gadolinium enhancement imaging for infarct assessment. LV blood flow KE parameters were indexed to LV end-diastolic volume and include: averaged LV, minimal, systolic, diastolic, peak E-wave and peak A-wave KEiEDV. In addition, we investigated the in-plane proportion of LV KE (%) and the time difference (TD) to peak E-wave KE propagation from base to mid-ventricle was computed. Association of LV blood flow KE parameters to LV function and infarct size were investigated in all groups.ResultsLV KEiEDV was higher in controls than in MI patients (8.5 ± 3 μJ/ml versus 6.5 ± 3 μJ/ml, P = 0.02). Additionally, systolic, minimal and diastolic peak E-wave KEiEDV were lower in MI (P < 0.05). In logistic-regression analysis, systolic KEiEDV (Beta = − 0.24, P < 0.01) demonstrated the strongest association with the presence of MI. In multiple-regression analysis, infarct size was most strongly associated with in-plane KE (r = 0.5, Beta = 1.1, P < 0.01). In patients with preserved LV ejection fraction (EF), minimal and in-plane KEiEDV were reduced (P < 0.05) and time difference to peak E-wave KE propagation during diastole increased (P < 0.05) when compared to controls with normal EF.ConclusionsReduction in LV systolic function results in reduction in systolic flow KEiEDV. Infarct size is independently associated with the proportion of in-plane LV KE. Degree of LV impairment is associated with TD of peak E-wave KE. In patient with preserved EF post MI, LV blood flow KE mapping demonstrated significant changes in the in-plane KE, the minimal KEiEDV and the TD. These three blood flow KE parameters may offer novel methods to identify and describe this patient population.

Kullback–Leibler and relative Fisher information as descriptors of locality

AbstractKullback–Leibler and relative Fisher information functionals are applied in studying deviation from local density approximation. The reduced density gradient s and the local kinetic energy parameter α are key ingredients of these new locality descriptors. The relative Kullback–Leibler information density contains extra knowledge as it is negative where the given probability density is smaller than the reference density. The relative Fisher information incorporates the highest order deviations from the uniform electron gas approximation.

Performance Measurement Methodologies and Metrics for Vibration Energy Scavengers

This paper deals with measurement methodologies for establishing indicators and metrics in order to assess the performance of vibration energy scavengers. The measurement method proposed here is based on the analysis of the flow of energy through several sections of the harvester, which sometime can include complex architectures and nonlinear phenomena. It is worth noting that the proposed solution is applicable not only to linear transducers in presence of periodic vibration source, as mainly proposed in the literature, but also to nonlinear harvester with its conditioning architectures/circuits and in presence of both stochastic and periodic sources. In this context, all the features have been studied from a generalized point of view which can be applied to study a wide range of Lead Zirconate Titanate-based architectures also exploring the effect of parameters variation, transducer architecture, and its consequence in terms of output performance as function of the kinetic input energy parameters. In particular, we outline a new metric addressing the limits of current solutions which the focus on a specific prototype composed of a single transduction element. This paper develops, from theory, a metric for analyzing the implementation of a performance measurement strategy and, in order to experimentally validate this methodology, considers four case studies, which represent the most popular architectures of scavengers proposed in the literature. The metric is first introduced, than the principle of the transducers under analysis is presented, analytical models have been developed, then, numerical analyses have been performed and the obtained behaviors have been validated from an experimental point of view, including characterization and performance evaluation; a comparison as respect the current figure of merits, applied in a specific device, has also been accomplished highlighting the suitability of the proposed methodology.

Cavitating flow characteristics, cavity potential and kinetic energy, void fraction and geometrical parameters – Analytical and theoretical study validated by experimental investigations

Analytical and theoretical discussions validated by experimental investigations are presented to comprehensively study the relation between the geometrical parameters, such as the dimensionless standoff distance and nozzle geometry, and the cavity potential energy, and void fraction to improve the performance of submerged cavitating water jets. The force generated by the collapse of cavitation clouds was employed to initiate cavitation erosion in copper test samples under various hydrodynamic and geometrical conditions. The nozzle diameter and the separation distance between the nozzle and the specimen were varied in order to determine the optimal geometrical configuration, which leads to maximal erosion rate. The damaged specimens were investigated using optical and scanning electron microscopy (SEM). The obtained results – along with selected, previously published works from the literature – verify the analytically derived formulas, which emphasize the connection between the dimensionless standoff distance, and the cavitation intensity, potential energy, void fraction, and indicate the existence of an optimal dimensionless standoff distance for maximal erosion rate. Formulas to conveniently compare the efficiency of a cavitating jet based on energy consumption and dimensionless standoff distance are also presented and demonstrated. The influence of nozzle diameter and standoff distance on the kinetic energy and the specific energy consumption was clearly observed.