Average Amplitude Research Articles

Properties of Flapping Current Sheet of the Martian Magnetotail

AbstractKnowing the properties of the Martian magnetotail flapping waves is critical to understand the dynamics of the Martian induced magnetosphere. Based on the measurements by Mars Atmosphere and Volatile EvolutioN and a newly developed method, we provide the first quantitative study of Martian magnetotail flapping waves in comparison with Earth's magnetotail flapping waves. We found that the period of Martian magnetotail flapping waves ranges from ∼50 to ∼250 s. The estimated average wave amplitude is ∼380 km, and the wavelength is ∼1,100 km. The estimated propagation speed ranges from ∼3 to ∼30 km/s, which is about a third of that of Earth's magnetotail flapping waves, and the speed declines with the increase of the current sheet thickness. Intriguingly, we found that the flapping waves with shorter periods, or lower wavelengths, can propagate faster, showing similar dispersive signatures as that found in the Earth's magnetotail. Our results demonstrate that the fluctuated field energy carried by flapping waves within unit time along unit magnetotail length is one order higher than that of Earth's flapping waves, as normalized by the magnetic energy of planetary magnetotail. Thus, in comparison with Earth's magnetotail, the flapping waves of Martian induced magnetotail would play a more important role in affecting the magnetotail dynamics.

Detection of millihertz quasi-periodic oscillations in the low-mass X-ray binary 4U 1730–22 with NICER

ABSTRACT We report the discovery of millihertz quasi-periodic oscillations (mHz QPOs) from the neutron star (NS) low-mass X-ray binary 4U 1730–22 using the Neutron Star Interior Composition Explorer (NICER). After being inactive for almost 50 years, 4U 1730–22 went into outburst twice between June and August 2021, and between February and July 2022. We analyse all the NICER observations of this source, and detect mHz QPOs with a significance > 4 σ in 35 observations. The QPO frequency of the full data set ranged between ∼ 4.5 and ∼ 8.1 mHz with an average fractional rms amplitude of the order of ∼2 per cent. The X-ray colour analysis strongly suggests that 4U 1730–22 was in a soft spectral state during the QPO detections. Our findings are consistent with those reported for other sources where the mHz QPOs have been interpreted as the result of a special mode of He burning on the NS surface called marginally stable nuclear burning (MSNB). We conclude that the mHz QPOs reported in this work are also associated with the MSNB, making 4U 1730–22 the eighth source that shows this phenomenology. We discuss our findings in the context of the heat flux from the NS crust.

The effect of quercetin on absence epilepsy in WAG/Rij rats

ABSTRACT Aim In the present study, the effect of quercetin, a powerful antioxidant flavonoid, on genetic absence epilepsy was studied in WAG/Rij rats. Material and Method Tripolar electrodes were implanted into WAG/Rij rats. Basal electrocorticography (ECoG) was recorded following a recovery period. After basal ECoG recording, different doses of quercetin (QRC) (25, 50 and 100 mg/kg) were injected intraperitoneally (i.p.) for 30 days. ECoG recording was continued for 31 days, three hours a day. After recording, the rats were anesthetized and euthanized through cervical dislocation and their brains were excised. Biochemically, TNF-alpha, IL-6 and NO were studied in whole rat brains. Results In WAG/Rij rats, low-dose quercetin (25 mg/kg) reduced the number and duration of spike-wave discharges (SWDs) compared to the control group. However, 50 and 100 mg/kg quercetin doses increased SWDs. Duration of SWDs was prolonged only with 100 mg/kg dose. None of the quercetin doses had any effect on average amplitude of SWDs. In addition, it was observed in biochemical analyses that 25 mg/kg quercetin reduced TNF-alpha, IL-6 and NO levels compared to the control group. While TNF-alpha and IL-6 levels in rat brains were not affected by 50 or 100 mg/kg doses, both doses were found to increase NO levels in rat brains. Conclusion Based on the results of the present study, 25 mg/kg low-dose quercetin may have reduced absence seizures by reducing proinflammatory cytokines and NO, but high-dose quercetin may have increased absence seizures through increasing the NO level. This contrasting effect of quercetin on absence seizures needs to be investigated by advanced mechanisms.

Inversion of reclaimed soil water content based on a combination of multi-attributes of ground penetrating radar signals

Rapid, accurate, and non-destructive acquisition of the distribution of reclaimed soil moisture information can provide data for the rapid monitoring of reclaimed soil in areas experiencing coal mining subsidence. However, the water content inversion methods based on ground penetrating radar (GPR) are mostly single-attribute analysis methods, which are easily affected by the soil structure. This paper proposes a multi-attribute joint analysis method, which can reduce the influence of complex soil structure on the prediction results. Surveys and soil sampling using GPR were performed on a subsided reclamation area in Huaibei City, Anhui Province, China. Correlation analysis of GPR attribute information and volumetric water content (VWC) showed that frequency peak (FP), average envelope amplitude (AEA), energy, instantaneous amplitude area, instantaneous frequency area, and average instantaneous frequency values were significantly related to the VWC of reclaimed soil. The applicability of different single-attribute analysis methods under the condition of reclaimed soil was compared. Results showed that the predictive effects of FP and AEA attributes were better than other attributes. Generally, the single-attribute analysis method was greatly affected by the structure of reclaimed soil, so the accuracy and reliability of this method need to be further optimized. The prediction results of the single- and multi-attribute joint analysis methods in the structure of reclaimed soil were compared and analyzed. This showed that the prediction accuracy and model reliability of the multi-attribute method are both higher than those of the single-attribute method. The multi-attribute method can overcome the problem of insufficient accuracy of water content detection of ground-seeking radar in soil with a complex structure. Finally, the multi-attribute method was used to obtain the water distribution information in the reclamation area. Results of this study provide new methods and ideas for the prediction of water content by GPR in soils with complex structure.

Effect of Liquid Cooling Structure of Confluence Channel on Thermal Performance of Lithium-Ion Batteries

AbstractIn this study, based on the liquid cooling method, a confluence channel structure is proposed, and the heat generation model in the discharge process of three-dimensional battery module is established. The effects of channel structure, inlet mass flowrate, and coolant flow direction on the heat generation of the battery module were studied by control variable method. Simulation results show that the confluence channel structure (e) shows good cooling effect on the battery temperature when controlling the 5 C discharge of the battery module. In addition, compared with the straight channel under the same working condition. In the discharge process of battery module, average temperature amplitude in battery module decreased by 17.3%, the inlet and outlet pressure is reduced by 16.47%, and the maximum temperature amplitude is reduced by 20.3%. Effectively improve temperature uniformity and reduce pressure drop. The problem of uneven temperature distribution caused by uneven velocity distribution of coolant in traditional straight channel is improved. At the same time, the design of the confluence structure accelerates the heat transfer of the channel plate and provides a new idea for the design of the cooling channel.

Single-Layered Phase-Change Metasurfaces Achieving Polarization- and Crystallinity-Dependent Wavefront Manipulation

As a promising platform for versatile electromagnetic (EM) manipulations, metasurfaces have drawn wide interest in recent years due to their unique EM properties and small footprints. However, although great efforts have been made to achieve multifunctionalities, the design of tunable metasurfaces with high compactness is still challenging. Here, a simple yet powerful design methodology for single-layered reconfigurable metasurfaces composed of nonvolatile phase-change material Ge2Sb2Se4Te1 (GSST) is proposed with average working amplitudes of 72.6% and 53% at different crystallization levels. The proposed metasurfaces could not only enable independent phase control at different crystallization levels but also introduced another polarization degree of freedom. As a proof of concept, we numerically demonstrate three kinds of metadevices in the infrared region achieving a multi-focus metalens with tunable foci, multistate vortex beam generator with adjustable topological charges and multi-channel meta-hologram with three independent information channels. It is believed that these multifunctional metasurfaces with both tunability and compactness are promising for various applications including information encryption, chiroptical spectroscopy, chiral imaging and wireless communication.

Insertable cardiac monitor with a long sensing vector: Impact of obesity on sensing quality and safety.

Fat layers in obese patients can impair R-wave detection and diagnostic performance of a subcutaneous insertable cardiac monitor (ICM). We compared safety and ICM sensing quality between obese patients [body mass index (BMI) ≥ 30 kg/m2] and normal-weight controls (BMI <30 kg/m2) in terms of R-wave amplitude and time in noise mode (noise burden) detected by a long-sensing-vector ICM. Patients from two multicentre, non-randomized clinical registries are included in the present analysis on January 31, 2022 (data freeze), if the follow-up period was at least 90 days after ICM insertion, including daily remote monitoring. The R-wave amplitudes and daily noise burden averaged intraindividually for days 61-90 and days 1-90, respectively, were compared between obese patients (n = 104) and unmatched (n = 268) and a nearest-neighbour propensity score (PS) matched (n = 69) normal-weight controls. The average R-wave amplitude was significantly lower in obese (median 0.46 mV) than in normal-weight unmatched (0.70 mV, P < 0.0001) or PS-matched (0.60 mV, P = 0.003) patients. The median noise burden was 1.0% in obese patients, which was not significantly higher than in unmatched (0.7%; P = 0.056) or PS-matched (0.8%; P = 0.133) controls. The rate of adverse device effects during the first 90 days did not differ significantly between groups. Although increased BMI was associated with reduced signal amplitude, also in obese patients the median R-wave amplitude was >0.3 mV, a value which is generally accepted as the minimum level for adequate R-wave detection. The noise burden and adverse event rates did not differ significantly between obese and normal-weight patients.Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT04075084 and NCT04198220.

Enhancing the Performance of Global Optimization of Platinum Cluster Structures by Transfer Learning in a Deep Neural Network.

The global optimization of metal cluster structures is an important research field. The traditional deep neural network (T-DNN) global optimization method is a good way to find out the global minimum (GM) of metal cluster structures, but a large number of samples are required. We developed a new global optimization method which is the combination of the DNN and transfer learning (DNN-TL). The DNN-TL method transfers the DNN parameters of the small-sized cluster to the DNN of the large-sized cluster to greatly reduce the number of samples. For the global optimization of Pt9 and Pt13 clusters in this research, the T-DNN method requires about 3-10 times more samples than the DNN-TL method, and the DNN-TL method saves about 70-80% of time. We also found that the average amplitude of parameter changes in the T-DNN training is about 2 times larger than that in the DNN-TL training, which rationalizes the effectiveness of transfer learning. The average fitting errors of the DNN trained by the DNN-TL method can be even smaller than those by the T-DNN method because of the reliability of transfer learning. Finally, we successfully obtained the GM structures of Ptn (n = 8-14) clusters by the DNN-TL method.

Seasonal variations and controlling factors of speleothem multi-proxy in southeastern China: Implications for the reconstruction of precipitation seasonality

Precipitation in southeastern China exhibits strong seasonal variability, which significantly impacts local agricultural production and social development. However, the reconstruction of precipitation seasonality has been limited by the lack of precisely dated high-resolution paleoclimatic records. This study presents seasonal-scale multi-proxy records (trace elements: Mg/Ca, Sr/Ca Ba/Ca and stable isotopes: δ18O and δ13C) of a modern (1810–2009 AD) annually laminated stalagmite (EM1) from E’Mei Cave, Jiangxi Province in southeastern China. Comparative analysis of observation data with meteorological and simulation data shows that the seasonal variation of EM1 δ18O, derived from precipitation δ18O, is mainly controlled by the large-scale circulation and precipitation seasonality on an interannual timescale. The seasonal EM1 δ18O variation is controlled by the seasonal precipitation δ18O, however, the most negative values of EM1 δ18O are higher than those of simulated calcite δ18O and the average amplitude of the seasonal variation of EM1 δ18O (∼1.93‰) is much smaller than that of simulated calcite δ18O (∼9.72‰) because of evaporation and mixing of waters in the epikarst system. On the decadal timescales, variations of δ13C, Mg/Ca, Sr/Ca, and Ba/Ca were found to be strongly correlated, consistent with the variation of the local dry/flood index, indicating a common influencing factor of local hydroclimate change. However, their seasonal phase relationships vary between strong and weak summer monsoon conditions. We find a strong covariation between Mg/Ca and δ13C with Sr/Ca and Ba/Ca during the strong monsoon period (1951–1976), and they are in antiphase with seasonal δ18O variation. However, the seasonal variations of Sr/Ca and Ba/Ca transformed to dominantly antiphase with Mg/Ca and δ13C during the weak monsoon period (1977–1991 AD). Therefore, we suggest that Mg/Ca and δ13C are dominantly controlled by the local hydroclimate changes on seasonal timescales but Sr/Ca and Ba/Ca might have been affected by complex processes in the epikarst under different hydrothermal configuration conditions. The findings indicate the potential of the variation of the seasonal phase relationships between multi-proxy records in reconstructing precipitation seasonality changes under different hydrothermal backgrounds.

Falling Estimation Based on PoseNet Using Camera with Difference Absolute Standard Deviation Value and Average Amplitude Change on Key-Joint

Elderly people need special attention and some of them need to be monitored continuously and in real-time. Fall detection is one of the systems used to monitor the daily life of the elderly. Various devices and methods were developed to monitor the condition of the elderly on daily activity. The system that has been proposed in previous studies uses a number of sensors that are placed on the body. However, this system tends to be high cost, complex installation, and inconvenient to use. Therefore, an alternative system is needed to overcome this problem. The purpose of this study is to developed a fall detection method using PoseNet with pose calculations based on key joins. Testing on larger data sets is needed to verify the proposed method's performance further. The use of cameras can be a solution to monitoring the activities of the elderly. With the image processing method, it is possible to estimate the activities of the elderly. The purpose of this study is to developed a fall detection method using PoseNet with pose calculations based on key joins. This study developed a fall detection method using PoseNet with pose calculations based on key joins. The key-join used is Left and Right Shoulder and is only measured at the y-coordinate. We calculated the difference absolute standard deviation value (DASDV) and average amplitude change (AAC) on the Y-coordinate. From 10 falling and non-falling conditions trials, we obtained 85% and 80% accuracy for AAC and DASDV. The result of this research can be used as a source or comparison for future research.

Experimental study on positive corona discharge characteristics in plane-single/double earthed rods air gaps under negative DC voltage

In order to analyze the corona discharge characteristics at the grounding object tip under the thundercloud electric field environment, scaled simulation test has been conducted on corona discharge in the plane-single/double earthed rods air gap. Five gap configurations with three different grounding rods were built during experiments. Factors as rod tip curvature, voltage and gap configuration have been considered in detail. Corona voltage, corona current and the number of ultraviolet photons were all recorded. The grounding rod tip curvature radius can affect corona discharge processes at grounding rod tip. With increasing applied negative DC voltage, five typical corona processes of dark discharge, burst streamer corona, periodic streamer corona, glow corona and brush discharge occurred at conical and spherical grounding rod tip (r=0.75cm), but under d=5cm and d=10cm no glow corona and brush corona appeared at spherical grounding rod tip (r=1.25cm). It is much easier for grounding rod tip with smaller curvature to form glow corona phenomenon. The mean value Iav of periodic streamer corona current pulse amplitude decreases with grounding rod tip curvature radius, while the mean corona current pulse width and pulse interval increases. For grounding rod with conical tip, there is little difference of average current pulse amplitude between periodic streamer corona and brush corona; for grounding rod with spherical tip (r=0.75cm), the mean value Iav of brush corona pulse amplitude increases to 3595.8 μA which has increased by a factor of about 36. The photon number at conical grounding rod tip is larger than that at spherical grounding rod tip at low voltage but the relation reverses as the applied voltage exceeds a critical value. The shielding effect of two grounding rods in plane-double rods air gaps increased with spherical grounding rod curvature radius and decreases with the lateral gap distance between two grounding rods.

Methane Emission and Metabolic Status in Peak Lactating Dairy Cows and Their Assessment Via Methane Concentration Profile

Abstract Ruminant husbandry contributes to global methane (CH4) emissions and beside its negative impact on the environment, enteric CH4 emissions cause a loss of gross energy intake in cows. The study is aimed to estimate CH4 emission and metabolic status in dairy cows via the methane concentration profile as a tool for analyzing the CH4 production pattern. The study included eighteen cows whose enteric CH4 emission was measured during three consecutive days in three periods: 2 hours before (P1), 2–4 hours (P2) and 6–8 hours (P3) after the morning feeding. Based on CH4 enteric emissions, cows were divided into two groups (n=6, respectively): HM (average CH4 concentration: 5430.08 ± 365.92 ppm) and LM (average CH4 concentration: 1351.85 ± 205.20 ppm). Following CH4 measurement, on day 3, venous blood was sampled to determine the indicators of the metabolic status. HM cows had significantly higher average CH4 concentrations, maximum and average CH4 peak amplitude than LM cows in all measuring periods (P1-P3), while the number of CH4 peaks tended to be higher in HM than in LM cows in P2. There were no differences in the maximum and average CH4 peak width and average distance among two CH4 peaks between examined groups of cows. HM cows had significantly higher total protein concentrations and significantly lower total bilirubin and NEFA concentrations than LM cows. In conclusion, HM cows have a greater number of eructations and release more CH4 per eructation than LM cows, hence the differences in metabolic status are most likely related to the differences in their liver function.

The Sun at millimeter wavelengths

Aims. We used solar observations of a plage-enhanced network with the Atacama Large Millimeter/sub-millimeter Array (ALMA) in Band 3 and Band 6, together with synthetic continuum maps from numerical simulations with Bifrost in the same bands, to carry out a detailed study of bright small-scale magnetic features. Methods. We made use of an algorithm to automatically identify and trace bright features within the field of view (FoV) of the ALMA observations and the simulation. In particular, the algorithm recovers information of the time evolution of the shape, motion of the centre of gravity, temperature, and size for each feature. These quantities are used to determine the oscillatory properties of each feature utilising wavelets analysis. Results. We found 193 and 293 features in the Bands 3 and 6 observations, respectively. In the degraded simulation, the total number of features were 24 for Band 3 and 204 for Band 6. In the original simulation, the total number of features were 36 for Band 3 and 392 for Band 6. Based on the simulation, we confirm the magnetic nature of the features. We have obtained average oscillation periods of 30–99 s for the temperature, 37–92 s for size, and 37–78 s for horizontal velocity. There are indications for the possible presence of transverse (kink) waves with average amplitude velocities of 2.1–5.0 km s−1. We find a predominant anti-phase behaviour between temperature and size oscillations suggesting that the variations of the bright features are caused by compressible fast-sausage magnetohydrodynamics (MHD) modes. For the first time to our knowledge, we estimated the flux of energy of the fast-sausage waves at the chromospheric heights sampled by ALMA as 453–1838 W m−2 for Band 3 and 3640–5485 W m−2 for Band 6. Conclusions. We have identified MHD waves, both transverse (kink) and compressible sausage modes, in small-scale (magnetic) structures, independently, in both ALMA Band 3 and Band 6 observations, along with their corresponding synthetic images from simulations. The decrease of wave energy-flux with height (from Band 6 to Band 3) could possibly suggest energy dissipation at chromospheric heights, namely, wave heating, with the assumptions that the identified small-scale waves are typical at each band and they propagate upward through the chromosphere.

Numerical Investigation of Vibration Suppression for the Combined Device of Non-Newtonian Fluids Coupled Elastic Baffle

Tuned liquid dampers (TLDs) have been broadly applied to suppress structural vibrations. In the present study, a novel vibration mitigation device consisting of non-Newtonian fluids coupled with an elastic baffle is proposed. The fluid-structure interaction is studied numerically. To optimize the system, different fluids, including the Bingham fluid, the Pseudoplastic fluid, and the Dilatant fluid are used as the damping fluids and the vibration suppression ability of each fluid is studied. Moreover, the energy dissipation mechanisms of different liquids are obtained. The results show that the optimal vibration suppression in the container without a baffle can be achieved by using the Bingham fluid. In this case, the average amplitude decay rate of the container is 12.662% with about 0.199% improvement in the damping ratio when compared to water. In the container with an elastic baffle, however, both the Pseudoplastic fluid and the Dilatant fluid outperform water in the damping capacity. The average amplitude decay rates of these fluids are 50.960% and 43.794%, respectively. Moreover, their damping ratios are 0.035% and 0.019% higher than that of water, respectively.

Effects of Different Culture Densities on the Acoustic Characteristics of Micropterus salmoide Feeding

The intensity and frequency of the acoustic signals generated by different behaviors of largemouth bass (Micropterus salmoides) have different characteristics. The acoustic signals generated during feeding can be used to analyze the characteristic patterns of their used behavior, which can provide a theoretical basis for applications such as automatic feeding based on acoustic signals. We used passive acoustics combined with video to study the feeding acoustic signals of largemouth bass in a recirculating water culture system (4, 8, 12, and 16 fish/m3). The result of the time–frequency and power spectrum analysis of the feeding sound signals showed that the short-time average amplitude of the feeding signal was well distinguished from the background noise, both the swallowing and the chewing sounds were positively correlated with the culture density, and the correlation between the swallowing sound and number of fish was stronger; at different culture densities, the short-time average zero-crossing in the swallowing phase of the largemouth bass suddenly dropped to about 500 and rose to about 1000 in the chewing process. Therefore, both the chewing and the swallowing sounds can be used as parameters to automatically identify the largemouth bass feeding process signal. The spectrum entropy in the feeding process of the largemouth bass was maintained at about 4–6 for different culture densities. In the power spectrum, the main feeding sounding frequencies of the largemouth bass at different farming densities and the distinguishable spectral range of the background noised ranged from 1 to 20 kHz, the main peak frequency of the feeding sound was within the range of 1.2 to 3.0 kHz, and the main power value of the power spectrum was positively correlated with farming density.

Determination of periodic deformation from InSAR results using the FFT time series analysis method in Gediz Graben.

Permanent Scatterers (PS) point velocities obtained by the interferometric synthetic aperture radar (InSAR) method are generally determined using the linear regression model, which ignores periodic and seasonal effects. In this study, software was developed that can detect periodic effects by applying fast Fourier transformation (FFT) time series analysis to InSAR results. Using the FFT time series analysis, the periodic components of the surface movements at the PS points were determined, and then the annual velocity values free from periodic effects were obtained. The study area was chosen as the Gediz Graben, a tectonically active region where aseismic surface deformations have been observed in recent years. As a result, using the developed method, seasonal effects were successfully determined with the InSAR method at the PS points in the study area with a period of 384days and an average amplitude of 19mm. In addition, groundwater level changes of a water well in the region were modeled, and 0.93 correlation coefficient values were calculated between seasonal InSAR displacement values and water level changes. Thus, using the developed methodology, the relationship between the tectonic movement in the Gediz Graben in Turkey and the seasonal movements and the change in the groundwater level was determined.

The role of single trial variability in event related potentials in children with attention deficit hyperactivity disorder

ObjectiveChildren with attention deficit hyperactivity disorder (ADHD) show attenuated mean P3 component amplitudes compared to typically developing (TD) children. This finding may be the result of individual differences in P3 amplitudes, P3 latencies, and/or greater single trial variability (STV) in amplitude or latency, suggesting neural “noise.” MethodsEvent related potentials (ERPs) from 75 children with ADHD and 29 TD children were recorded with electroencephalography (EEG). Caregivers provided ratings on child ADHD symptoms. Single-trial ERP amplitudes and latencies were extracted from the P3 component time window during a visual oddball task. Additionally, we computed individual-centered and trial-centered P3 amplitudes to account for inter-individual and inter-trial variability in the timing of the P3 peak. ResultsIn line with prior research, greater ADHD symptom severity was associated with reduced mean P3 amplitude. This correlation was no longer significant after correcting for inter-trial differences in P3 latency. In contrast, greater ADHD symptom severity was associated with reduced STV in P3 amplitude. ConclusionsOur results suggest that attenuated average P3 amplitude in ADHD samples is due to a consistent reduction in strength of the neurophysiological signal at the single trial level, as well as increased inter-trial variability in the timing of P3 peak amplitudes. The traditional method of extracting P3 amplitudes based on a single time window for all trials may not adequately capture variability in P3 latencies associated with ADHD. SignificanceInter- and intra-individual differences in brain signatures should be considered in models of neurobiological differences in neurodevelopmental samples.

Profiling the low-beta characteristics of the subthalamic nucleus in early- and late-onset Parkinson's disease.

Low-beta oscillation (13-20 Hz) has rarely been studied in patients with early-onset Parkinson's disease (EOPD, age of onset ≤50 years). We aimed to explore the characteristics of low-beta oscillation in the subthalamic nucleus (STN) of patients with EOPD and investigate the differences between EOPD and late-onset Parkinson's disease (LOPD). We enrolled 31 EOPD and 31 LOPD patients, who were matched using propensity score matching. Patients underwent bilateral STN deep brain stimulation (DBS). Local field potentials were recorded using intraoperative microelectrode recording. We analyzed the low-beta band parameters, including aperiodic/periodic components, beta burst, and phase-amplitude coupling. We compared low-beta band activity between EOPD and LOPD. Correlation analyses were performed between the low-beta parameters and clinical assessment results for each group. We found that the EOPD group had lower aperiodic parameters, including offset (p = 0.010) and exponent (p = 0.047). Low-beta burst analysis showed that EOPD patients had significantly higher average burst amplitude (p = 0.016) and longer average burst duration (p = 0.011). Furthermore, EOPD had higher proportion of long burst (500-650 ms, p = 0.008), while LOPD had higher proportion of short burst (200-350 ms, p = 0.007). There was a significant difference in phase-amplitude coupling values between low-beta phase and fast high frequency oscillation (300-460 Hz) amplitude (p = 0.019). We found that low-beta activity in the STN of patients with EOPD had characteristics that varied when compared with LOPD, and provided electrophysiological evidence for different pathological mechanisms between the two types of PD. These differences need to be considered when applying adaptive DBS on patients of different ages.

Numerical investigation of oxygen bubble condensation in subcooled quiescent liquid oxygen based on height function method

Bubble condensation is a fundamental issue in the direct contact condensation (DCC) process, which is extremely hard to predict due to the intense mass transfer and flow instability. Aiming at the cryogenic oxygen bubble evolution and pressure oscillation, a modified energy balance mass transfer model is adopted based on the height function method. The height function method is used to calculate the real-time interfacial curvature, modifying the mass transfer rate that emerged in CFD simulation. The modified model is validated to be convincing and accurate by a steam bubble condensation simulation. The results indicate that the cryogenic bubbles condense faster with a more intense mass transfer process, compared with the near-room-temperature mediums. The corresponding amplitude of pressure oscillation for the cryogenic mediums is approximately 3 ∼ 4 times as larger as that for near-room-temperature mediums. It is found that both the condensation rate and the frequency of pressure oscillation are repressed with the increase of bubble volume. That means that a big bubble condensation might produce a low-frequency pressure oscillation. In addition, both the condensation rate and the intensity of the pressure oscillation increase with the increase of subcooling. The average amplitude of pressure oscillation has a power function law with subcooling. These conclusions provide a theoretical basis for a deep understanding of the cryogenic DCC process.

Condition Monitoring of Horizontal Sieving Screens—A Case Study of Inertial Vibrator Bearing Failure in Calcium Carbonate Production Plant

Predictive maintenance is increasingly popular in many branches, as well as in the mining industry; however, there is a lack of spectacular examples of its practice efficiency. Close collaboration between Omya Group and Wroclaw University of Science and Technology allowed investigation of the failure of the inertial vibrator's bearing. The signals of vibration are captured from the sieving screen just before bearing failure and right after repair, when it was visually inspected after replacement. The additional complication was introduced by the loss of stable attachment of the vibrator's shield, which produced great periodical excitation in each place of measurement on the machine. Such anomalies in the signals, in addition to falling pieces of material, made impossible the diagnostics by standard methods. However, the implementation of advanced signal processing techniques such as time-frequency diagrams, envelope spectrum, cyclic spectral coherence, orbits analysis, and phase space plots allowed to undermine defects (pitting on the inner ring). After repair, the amplitudes of vibration from the damaged bearing side were reduced by five times, while sound pressure was only two times lower. The quantitative parameters of vibrations showed significant changes: time series RMS (-68%) median energy of spectrograms (89%), frequencies ratio of cyclic spectral coherence (-85%), and average amplitude of harmonics in envelope spectrum (-80%). The orbits demonstrated changes in inclination angle (16%) and sizes (-48, … -96%), as well as phase space plots sizes (-28, … -67%). Directions of further research are considered.