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The results of experimental studies of the impact of mode parameters on power characteristics of the generator of plasma of N–O–C–H system and medium enthalpy of plasma, generated by the latter were presented. The studies were conducted in a two-electrode plasmatron with two schematic diagrams – with an automatic gas dynamic arc length stabilization and with a selfsetting arc. It is shown that all the benefi ts of using mixtures of air with a hydrocarbon gas are realized in the case of fi xing the arc length in the arc channel. The use of automatic gas dynamic arc length fi xation practically allows stabilizing the values of effi ciency throughout the whole range of changing generation mode parameters and, at the same time, eliminating the impact of effi ciency on the medium enthalpy of plasma fl ow. The transition to the system N - O (air) reduces the average level of effi ciency by 7…10 % and almost twice the value of medium enthalpy. The arsenal of means of infl uencing the mentioned parameters due to a constant composition of plasma gas reduces. The plasmotron with a self-setting arc on plasma-forming mixtures of the system N-O-C-H has by 15…20 % lower level of effi ciency values than in the case of fi xing the arc length. The medium enthalpy of plasma depends signifi cantly on the fl ow-rate and composition of plasma-forming gas. An increase in the values of medium enthalpy by an increase in the arc current leads to deterioration of power characteristics of the plasma generator. Coordination of own power characteristics of the device and parameters of plasma being generated can only be carried out only on the basis of a compromise. [ABSTRACT FROM AUTHOR]

• Theoretical analysis shows that radial transferred heat flow from pulse tube to regenerator can improve the cooling power. • CFD models with and without radial heat transfer based on a single-stage pulse tube cooler have been conducted. • Simulation results show that after introducing radial thermal conduction, cooling power is reduced by 5.8% as a result of the time-averaged radial heat flow from regenerator to pulse tube. • The influence of thermal conductivity of the coupled wall between outer components and inner components is investigated. A co-axial pulse tube cooler, whose regenerator normally surrounds the pulse tube, has the most compact structure. Internal radial thermal conduction may occur between the regenerator and pulse tube due to the temperature mismatch at the same axial location. Theoretical analysis indicates that radial transferred heat flow from pulse tube to regenerator can increase the cooling power, while the opposite radial heat flow which flows from regenerator to pulse tube would decrease the cooling power. Then CFD models with and without radial thermal conduction based on a practical single-stage pulse tube cooler have been conducted to further analyze the mechanism and effect. Simulation results show that after introducing radial thermal conduction, the maximum temperature difference between the gas in regenerator and pulse tube is reduced from 25 K to below 10 K, and cooling power is reduced by 5.8% as a result of the time-averaged radial heat flow from regenerator to pulse tube. The influence of thermal conductivity of the coupled wall between regenerator and pulse tube is also discussed. This study provides a better understanding on the radial heat thermal conduction in a single stage co-axial pulse tube cooler, which sets the basis for optimizing the geometrical arrangement of co-axial pulse tube coolers. [ABSTRACT FROM AUTHOR]

Introduction: Heart rate variability (HRV) is determined by the variation of consecutive cardiac electrical excitations, usually from RR intervals of an EKG. The sequence of intervals is a time series that yields three HRV parameter categories: time domain, frequency domain, and nonlinear. Parameter estimates are based on widely different EKG sample times: short-term (~5-10 minutes), longer (24 hours), and ultra-short (<5 minutes). Five-minute intervals are useful to evaluate intervention effects that change HRV in a single session by comparing pre-to-post values. This approach relies on knowing the minimal detectible change (MDC) that indicates a real change in clinical and research studies. The specific aims of this pilot study were to (1) evaluate HRV power and its spectral distribution among contiguous five-minute intervals, (2) compare the power distribution in a five-minute interval with a full 45-minute assessment, and (3) provide data to aid estimation of the MDC between pre- and post-interventions during a single session.  Methods: Twelve self-reported healthy young adults participated after signing an approved consent. Participation required subjects who had no history of cardiovascular disease or were taking vasoactive substances. Persons with diabetes were not eligible. While subjects were supine, EKG leads were placed, and EKG was recorded for 45 minutes at 1000 samples/sec. The 45 minutes were divided into nine five-minute contiguous intervals, and the spectral density in each was determined. Total power and spectral percentages within each interval were assessed in the very low (VLF, 0.003-0.04 Hz), low (LF, 0.04-0.15 Hz), and high (HF, 0.15-0.4 Hz) frequency bands. These were compared among intervals and to the full 45-minute sample. The MDC was determined by comparing powers in five-minute intervals separated by 10 minutes. The standard error of the measurement (SEME) for each pair was calculated from the square root of the mean square error (√MSE). MSE was based on a two-factor analysis of variance, and MDC was 2×√2×SEME., Results: Differences in total power and spectral power distribution among intervals were not statistically significant. The total mean power±SD was 4561±1434 ms². The maximum difference in total power was 7.85%. The mean power for the VLF, LF, and HF bands was respectively 1713±1736 ms², 1574±1072 ms², and 1257±1016 ms². The maximum percentage difference in spectral power across all intervals for VLF, LF, and HF was respectively 3.75%, 8.5%, and 7.4%. The percentage of power in the VLF, LF, and HF bands was respectively 37.9%, 36.1%, and 25.9%. The ratios of spectral to total power for VLF, LF, and HF bands were respectively 0.80±0.07, 1.20±0.11, and 1.22±0.10. MDC percentage values were 21.0±4.9% for the HF band, 25.7±1.4% for the LF band, and 30.4±5.5% for the VLF band., Conclusion: Results offer initial estimates of variations in HRV power in the VLF, LF, and HF bands in contiguous five-minute intervals and estimates of the minimum detectible "real" changes between intervals separated by 10 minutes. The pattern of variation and data are useful in experimental planning in which HRV spectral power changes are assessed subsequent to a short-duration intervention during a single session. MDC values (21.0% in the HF band to 30.4% in the VLF band) provide initial estimates useful for estimating the number of participants needed to evaluate the impact of an intervention on spectral components of HRV., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Nova Southeastern University Institutional Review Board issued approval #2019-598-NSU. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Mayrovitz et al.)

The purpose of study was to demonstrate age-related changes during gait initiation (GI). Therefore, displacement, velocity, total power, mean and median frequency of COP trajectories were measured during phases of GI in anteroposterior (AP) and mediolateral (ML) directions. The older group demonstrated the slower and lesser displacement in comparison with the younger group during anticipatory phase in AP direction and during locomotor phase in AP and ML directions. In addition, the median and mean frequency were greater in the older relative to the younger group during anticipatory phase in AP direction, while these were lesser in older than younger group during locomotor phase in AP and ML directions. Moreover, total power was greater among older than younger adults during the anticipatory phase in ML direction and during all phases in AP direction. This study suggests that COP-related parameters extracted from time and frequency domains have the ability to demonstrate age-related changes. [ABSTRACT FROM AUTHOR]

To systematically review the medical literature to determine the utility of heart rate variability in predicting mortality for moderate to severe traumatic brain injury. A search for randomized controlled trials, nonrandomized trials, and prospective and retrospective cohort studies was carried out using PubMed, SCOPUS, Cochrane Central Register of Controlled Trials, MEDLINE, and EMBASE. Reference lists of included studies were also searched to identify potentially eligible studies. Five articles comprising 542 patients met inclusion criteria. Heart rate variability as low-frequency/high-frequency ratio (area under the curve [AUC] receiver operating characteristic [ROC]) for predicting mortality was found to be statistically significant (AUC ROC 0.810, P < 0.001) with high heterogeneity (I 2 = 61.98%, P = 0.032). Meta-analysis of low-frequency/high-frequency ratio, High frequency peak, and total power were statistically significant for predicting mortality. Odd's ratio for predicting mortality for LF/HF ratio, HF peak, and TP were 16.17, 19.09, 22.59 respectively. High-frequency peak in predicting mortality showed an AUC ROC of 0.986 (P ≤ 0.001) with a low level of heterogeneity. Total power (TP) showed an AUC ROC of 0.93 (P < 0.001) in predicting mortality with a high level of heterogeneity (I 2 = 83.16%, P = 0.002). Funnel plot analysis to assess the presence of publication bias for TP showed a high level of heterogeneity and asymmetry among studies. This meta-analysis predicted high mortality based on odds ratio for variables low-frequency/high-frequency ratio, high-frequency peak, and TP. However, the statistical analysis was weakened owing to the high level of heterogeneity in the included studies. Further research is needed to generate high-quality recommendations regarding heart rate variability as a predictor of mortality after traumatic brain injury. [ABSTRACT FROM AUTHOR]

This article presents regression formulas for the preliminary design of tankers, bulk carriers and container vessels, based on the data of ships built from 2000 to 2018. The formulas could have practical application for the estimation of total engine power by using ship’s deadweight or TEU capacity and speed.

Accurate wake model in wind farm layout optimization can help extracting maximum power generation, minimizing cost of energy and prolonging wind turbines' lifetime as well. With the development of different wake models, the wind farm layout optimization results based on the models should be updated. This paper investigates the performances of four wake models in wind farm layout optimization using multi-population genetic algorithm (MPGA) with the wind farm power generation, COST/AEP and wind farm efficiency been reported. Comparison of results between typical wake models' performance shows that Jensen's wake model reported a higher wind farm power generation and efficiency because it underestimates the velocity deficit in the wake, and to the contrary, in the Frandsen wake model, the velocity in the wake is underestimated, resulting in a deceased power generation. The expression of 2D_k model shall be out of work in complicated wind condition. The 2D Jensen–Gaussian wake model performed better in the wind farm layout optimization using the MPGA program which can be promoted in real-world wind farm micrositing. [ABSTRACT FROM AUTHOR]

Sleep is a physiological state that plays important role in the recovery of fatigue. However, the relationship between the physiological status of sleep and subjective fatigue remains unknown. In the present study, we hypothesized that the non-recovery of fatigue at wake time due to non-restorative sleep might be ascribed to changes in specific parameters of electroencephalography (EEG) and heart rate variability (HRV) in poor sleepers. Twenty healthy female shift-working nurses participated in the study. Subjective fatigue was assessed using the visual analog scale (VAS) at bedtime and wake time. During sleep on the night between 2 consecutive day shifts, the EEG powers at the frontal pole, HRV based on electrocardiograms, and distal-proximal gradient of skin temperature were recorded and analyzed. The results indicated that the subjects with high fatigue on the VAS at wake time exhibited (1) a decrease in deep non-rapid eye movement (NREM) (stageN3) sleep duration in the first sleep cycle; (2) a decrease in REM latency; (3) a decrease in ultra-slow and delta EEG powers, particularly from 30 to 65 min after sleep onset; (4) a decrease in the total power of HRV, particularly from 0 to 30 min after sleep onset; (5) an increase in the very low frequency component of HRV; and (6) a smaller increase in the distal-proximal gradient of skin temperature, than those of the subjects with low fatigue levels. The correlational and structural equation modeling analyses of these parameters suggested that an initial decrease in the total power of HRV from 0 to 30 min after sleep onset might inhibit the recovery from fatigue during sleep (i.e., increase the VAS score at wake time) via its effects on the ultra-slow and delta powers from 30 to 65 min after sleep onset, stageN3 duration in the first sleep cycle, REM latency, and distal-proximal gradient of skin temperature. These findings suggest an important role of these physiological factors in recovery from fatigue during sleep, and that interventions to modify these physiological factors might ameliorate fatigue at wake time.

Sleep is a physiological state that plays important role in the recovery of fatigue. However, the relationship between the physiological status of sleep and subjective fatigue remains unknown. In the present study, we hypothesized that the non-recovery of fatigue at wake time due to non-restorative sleep might be ascribed to changes in specific parameters of electroencephalography (EEG) and heart rate variability (HRV) in poor sleepers. Twenty healthy female shift-working nurses participated in the study. Subjective fatigue was assessed using the visual analog scale (VAS) at bedtime and wake time. During sleep on the night between 2 consecutive day shifts, the EEG powers at the frontal pole, HRV based on electrocardiograms, and distal-proximal gradient of skin temperature were recorded and analyzed. The results indicated that the subjects with high fatigue on the VAS at wake time exhibited (1) a decrease in deep non-rapid eye movement (NREM) (stageN3) sleep duration in the first sleep cycle; (2) a decrease in REM latency; (3) a decrease in ultra-slow and delta EEG powers, particularly from 30 to 65 min after sleep onset; (4) a decrease in the total power of HRV, particularly from 0 to 30 min after sleep onset; (5) an increase in the very low frequency component of HRV; and (6) a smaller increase in the distal-proximal gradient of skin temperature, than those of the subjects with low fatigue levels. The correlational and structural equation modeling analyses of these parameters suggested that an initial decrease in the total power of HRV from 0 to 30 min after sleep onset might inhibit the recovery from fatigue during sleep (i.e., increase the VAS score at wake time) via its effects on the ultra-slow and delta powers from 30 to 65 min after sleep onset, stageN3 duration in the first sleep cycle, REM latency, and distal-proximal gradient of skin temperature. These findings suggest an important role of these physiological factors in recovery from fatigue during sleep, and that interventions to modify these physiological factors might ameliorate fatigue at wake time. [ABSTRACT FROM AUTHOR]

The aim of this study was to reveal the correlation between anxiety levels and heart rate variability (HRV) indices in adolescents with type1 diabetes mellitus (T1 DM). Sixty-four subjects were recruited for this study which included 33 patients with a diagnosis of T1 DM and 31 controls. Subjects were invited to the autonomic function testing laboratory (AFT lab), in the department of Physiology, for HRV analysis and anxiety level determination using a simple questionnaire called Hamilton's scale of anxiety. Anxiety levels were negatively correlated with percentage of normal-normal interval pNN 50 (r= -0.380, p<0.05), Standard deviation of normal-normal interval (r= -0.349, p<0.05), square root of the mean squared deviation (r= -0.384, p<0.05), very low frequency (r= -0.586, p< 0.01), low frequency LF (r= -0.048, p<0.01), high frequency HF (r= -0.351, p<0.05), total power (r= -0.468, p<0.01). Anxiety level was positively correlated with LF/HF ratio (r= 0.349, p<0.05) were found as indicated. There was no correlation between anxiety levels and biochemical parameters such as fasting blood glucose and glycated hemoglobin (HbA1c). Since HRV is a marker of parasympathetic activity, a negative correlation of anxiety levels with HRV parameters indicates reduced parasympathetic activity in patients with T1 DM. A positive correlation between anxiety levels and sympathovagal balance (LF/HF ratio) was observed because of reduced parasympathetic activity which is attributed to reduced HF. The outcomes of this preliminary suggest that anxiety appears to play an important role in reducing HRV in patients with T1 DM. [ABSTRACT FROM AUTHOR]

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The solution of some extreme problems for parameters that determine the energy performance of the three-phase power supply system in the sinusoidal unbalanced mode has been proposed: determination of total power and its quadratic components taking into account the ratio of resistances of the four-wire power cable, minimizing power losses and consumed rms current, maximizing the power factor. These results can be used to develop optimal control strategies of the parallel active filter to compensate the inactive components of total power under conditions of dynamic change of load parameters. References 7, figure 1. [ABSTRACT FROM AUTHOR]

When the signal-to-noise ratio (SNR) falls below a certain level, the error of the time-of-flight (ToF) maximum likelihood estimator abruptly increases due to the well-known threshold effect. Nevertheless, operating near and below the threshold SNR value might be necessary for many remote sensing applications due to power-related constraints. These constraints may include a limit on the maximum power of a single source pulse or a limit on the total power used by multiple signals transmitted during a single measurement. For narrow-band signals, the threshold effect emerges mostly due to outliers induced by local maxima of the autocorrelation function of a source signal. Following the previously explored path of biosonar-inspired echo processing, this paper introduces a new method for ToF estimation in the presence of outliers. The proposed method employs a bank of phase-shifted unmatched filters for generating multiple biased but only partially correlated estimators (multiple experts). Using machine learning techniques, the information from the multiple experts is combined together for improving the near-the-threshold ToF estimation from a single echo. [ABSTRACT FROM PUBLISHER]

Abstract: In this paper, we propose an efficient statistical full-chip total power estimation method considering process variations with spatial correlation. Traditionally, dynamic power and leakage power were computed separately as leakage power is more susceptible to process variations. But in the end, it is total power that designers will be concerned with. We propose a new method to compute the statistical total power via circuit level simulation under realistic input testing vectors. To consider the process variations with spatial correlation, we first apply principle factor analysis method (PFA) or its weighted version (wPFA) to transform the correlated variables into uncorrelated ones and meanwhile reduce the number of resulting random variables. Afterwards, Hermite orthogonal polynomials and sparse grid techniques are used to estimate total power distribution in a sampling way. The proposed method has no restrictions on models of statistical distributions for total powers. The method works well when strong spatial correlation exists among random variables in the chip. Experimental results show that the proposed method has 100X times speedup than the Monte Carlo method under fixed input vector and 20X times speedup than the Monte Carlo method considering both random input vectors and process variations with spatial correlation. [Copyright &y& Elsevier]

Quantizing the relationship between finger force and multitendoned extrinsic hand muscles could be useful for understanding the control strategies that underlie the coordination of finger movements and forces. The objective of this study is to explore the relationship of fingertip force production and total power of surface electromyography (sEMG) recorded on extrinsic hand muscles under isometric voluntary contraction. Thirteen healthy volunteers were recruited to participate in this study. In the designed force-tracking tasks, all volunteers were required to produce a certain force with either index finger or middle finger to match the target force for 5 s. Meanwhile, the sEMG signals were acquired from two extrinsic hand muscles: extensor digitorum (ED) and flexor digitorum superficialis (FDS). For each trial, sEMG of the effective force segment was extracted; then, the power spectrum was estimated based on autoregressive (AR) model and from which the corresponding total power of sEMG was computed. The experimental results reveal that the total power of sEMG linearly increases with force level regardless of the task finger and extrinsic hand muscle. It is also found that the total power obtained from index finger is significantly less than that of middle finger for FDS at the same force level (p < 0.05), while this kind of statistical significance cannot be found for ED. However, with respect to the measurement of total power, the type of extrinsic hand muscle has not exhibited significantly different contribution to the task finger under a certain fingertip force level. The findings of this study indicate that the total power of the extrinsic hand muscle's sEMG can be used to characterize finger's activities. [ABSTRACT FROM AUTHOR]

Aims: To analyze the event-related desynchronization/synchronization (ERD/ERS) attended with the mental load arising while solving two cognitive tasks. The features of the presented visual stimulus determined the type of cognitive task that should be solved. Methods: For each experimental task and everybody's subject FFT Analysis module calculated the total power histograms from a fixed frequency band (3-20 Hz or 8-13 Hz) for each 3-second EEG sample with 50 % overlay and all electrodes. From the histograms the software derived two FFT single values - The average Total Power (TP) and Frequency at Maximum Power (FMP). Results: It has been shown that during the solution of cognitive tasks the marked changes of ongoing EEG activity appeared. The short lasting and localized amplitude decrease in rhythmic activity (ERD) and the change of EEG frequency were among the most frequent. The ERD extent was determined by an informational content of processed visual stimuli and by the site of scalp-recording electrode. A higher mental load related to the solution of cognitive tasks shifted the average FM to lower frequencies. Conclusion: The suitability of an analysis of ongoing EEG activity to uncover differences in people's brain activation patterns when engaged in performing cognitively demanding tasks was proved. [ABSTRACT FROM AUTHOR]

In 2002, 2003 and 2004, field trials were carried out in Slovenia in the form of random blocks with five replications. Three potato cultivators/ridgers were used on medium textured soil. The aim was to establish which potato cultivator/ridger was the most suitable for inter-row space cultivation, ridge shaping and achievement of the highest possible potato yield, work-rate and productivity. A drawn cultivator/ridger with spring tines on a parallelogram framework and wing ridge heads attached (STC), was compared with a drawn cultivator/ridger with rigid tines on a parallelogram framework and cogwheel ridge discs attached (RTC) and with a rotary, PTO-driven cultivator/ridger (RC). The latter created the largest cross-sectional area of the ridge and proved to be the most efficient at crushing soil aggregates in the inter-row space and at ridge shaping. It also allowed the lowest cone resistance at the ridge centre and in the central part of the ridge side. A higher number of tubers per plant resulted from ridges made by the PTO-driven cultivator/ridger giving a higher total yield of tubers than with the other two cultivators/ridgers. In comparison with the drawn cultivators/ridgers, the PTO-driven cultivator/ridger shaped ridges with better physical properties on medium textured soil; however both drawn cultivators/ridgers had greater work-rates, and also needed less energy to cultivate a unit of area. [ABSTRACT FROM AUTHOR]

Abstract: In this study we investigated the hypothesis whether P2-related differences tested in a visual priming paradigm are associated with theta phase-locking. We recorded the EEG from 31 electrodes and calculated phase-locking index and total power differences for frequencies between 2 and 20Hz. ERPs (event-related potentials) were analyzed for P1, N1 and P2 components. P2 showed strongest task-related amplitude differences between congruent and incongruent targets. A source analyses was performed for the P2 component using sLoreta that revealed local generators of the P2 in parieto–occipital regions. Phase-locking analyses showed specific effects in the theta range (4–6Hz) appearing in time windows at around the P2 component. We draw the conclusion that phase-locked theta reflect top-down regulation processes mediating information between memory systems and is in part involved in the modulation of the P2 component. [Copyright &y& Elsevier]

: ObjectivesThe aim of this study was to explore the value of noninvasive predictors of death/mode of death in ambulant outpatients with chronic heart failure (HF).: BackgroundMortality in chronic HF remains high, with a significant number of patients dying of progressive disease. Identification of these patients is important.: MethodsWe recruited 553 ambulant outpatients age 63 ± 10 years with symptoms of chronic HF (New York Heart Association functional class, 2.3 ± 0.5) and objective evidence of left ventricular dysfunction (ejection fraction <45%, cardiothoracic ratio >0.55, or pulmonary edema on chest radiograph). After 2,365 patient-years of follow-up, 201 patients had died, with 76 events due to progressive HF.: ResultsIndependent predictors of all-cause mortality assessed with the Cox proportional hazards model were as follows: a low standard deviation of all normal-to-normal RR intervals (SDNN); lower serum sodium and higher creatinine levels; higher cardiothoracic ratio; nonsustained ventricular tachycardia; higher left ventricular end-systolic diameter; left ventricular hypertrophy; and increasing age. Independent predictors of death specific to progressive HF were SDNN, serum sodium and creatinine levels. The hazard ratio of progressive HF death for a 10% decrease in SDNN was 1.06 (95% confidence interval [CI], 1.01 to 1.12); for a 2 mmol/l decrease in serum sodium, 1.22 (95% CI, 1.08 to 1.38); and for a 10 μmol/l increase in serum creatinine, 1.14 (95% CI, 1.09 to 1.19) (all p < 0.01).: ConclusionsIn ambulant outpatients with chronic HF, low serum sodium and SDNN and high serum creatinine identify patients at increased risk of death due to progressive HF. [Copyright &y& Elsevier]

The effects of the zeroth-order diffraction of a phase mask on the creation of Bragg gratings using the mask technique were theoretically and experimentally investigated. Experimental results showed that the zeroth-order diffraction of 1% total power, while in interference with the first-order diffraction of 44% each, dramatically affected the structure of the gratings in a polymer optical preform, including their period. Theoretical analysis by taking the zeroth-order diffraction into account predicted that a very small part of the zeroth-order component (0.1%) would have substantial effects on the gratings, which will be no longer uniform along both the directions of the incident laser beam propagation and the groove array. Theoretical calculation agrees well with the experimental results [ABSTRACT FROM PUBLISHER]