Numerical Study of the Wake Flow of a Wind Turbine with Consideration of the Inflow Turbulence

Considering the fact that wind turbines operate at the bottom of the atmospheric boundary layer (ABL) where the turbulence is at a high level, and the difficulty of mesh generation in the fully modeled numerical simulation, it is necessary to carry out researches to study the wake flow of wind turbines with consideration of the inflow turbulence. Therefore, a numerical method generating turbulence was proposed and the results show good agreement with those in experiments, based on which the flow fields in the wake of a wind turbine at two tip speed ratios are examined in detail through three actuator methods, namely, ADM, ADM-R and ALM. The performances of these methods were studied and the error sources for each method are clarified. Moreover, the computational efficiency were revealed and the influencing factor for the efficiency is concluded. Besides, the equilibrium relation of the N-S equation in the wake is revealed, which provides a theoretical basis for the optimal arrangement of the wind turbine. It shows that the mean velocity and fluctuating velocity vary greatly near the wind turbine, and become stable gradually away from the wind turbine. The results of ALM method shows the best agreement with the experiment. At near wake region, the turbulent stress term, pressure gradient term and convection term mainly contribute to the equation equilibrium, and convection term is in equilibrium with the turbulent stress term at the far wake

Extensive Crosstalk between O-GlcNAcylation and Phosphorylation Regulates Akt Signaling

O-linked N-acetylglucosamine glycosylations (O-GlcNAc) and O-linked phosphorylations (O-phosphate), as two important types of post-translational modifications, often occur on the same protein and bear a reciprocal relationship. In addition to the well documented phosphorylations that control Akt activity, Akt also undergoes O-GlcNAcylation, but the interplay between these two modifications and the biological significance remain unclear, largely due to the technique challenges. Here, we applied a two-step analytic approach composed of the O-GlcNAc immunoenrichment and subsequent O-phosphate immunodetection. Such an easy method enabled us to visualize endogenous glycosylated and phosphorylated Akt subpopulations in parallel and observed the inhibitory effect of Akt O-GlcNAcylations on its phosphorylation. Further studies utilizing mass spectrometry and mutagenesis approaches showed that O-GlcNAcylations at Thr 305 and Thr 312 inhibited Akt phosphorylation at Thr 308 via disrupting the interaction between Akt and PDK1. The impaired Akt activation in turn resulted in the compromised biological functions of Akt, as evidenced by suppressed cell proliferation and migration capabilities. Together, this study revealed an extensive crosstalk between O-GlcNAcylations and phosphorylations of Akt and demonstrated O-GlcNAcylation as a new regulatory modification for Akt signaling

A Reliability Optimization Algorithm for Wireless Sensor Network

Aiming at the reliability optimization algorithm based on wireless sensor network, a data fusion algorithm based on extreme learning machine for wireless sensor network was proposed according to the temporal spatial correlation in data collection process. After analyzing the principles, design ideas and implementation steps of extreme learning machine algorithm, the performance and results were compared with traditional BP algorithm, LEACH algorithm and RBF algorithm in simulation environment. The simulation results showed that the data fusion optimization algorithm based on the limit learning machine for wireless sensor network was reliable. It improved the efficiency of fusion and the comprehensive reliability of the network. Thus, it can prolong the life cycle and reduce the total energy consumption of the network

map-numa: access patterns used to characterize the numa memory access optimization techniques and algorithms

Some typical memory access patterns are provided and programmed in C, which can be used as benchmark to characterize the various techniques and algorithms aim to improve the performance of NUMA memory access. These access patterns, called MAP-numa (Memory Access Patterns for NUMA), currently include three classes, whose working data sets are corresponding to 1-dimension array, 2-dimension matrix and 3-dimension cube. It is dedicated for NUMA memory access optimization other than measuring the memory bandwidth and latency. MAP-numa is an alternative to those exist benchmarks such as STREAM, pChase, etc. It is used to verify the optimizations' (made automatically/manually to source code/executive binary) capacities by investigating what locality leakage can be remedied. Some experiment results are shown, which give an example of using MAP-numa to evaluate some optimizations based on Oprofile sampling. © IFIP International Federation for Information Processing 2012.Some typical memory access patterns are provided and programmed in C, which can be used as benchmark to characterize the various techniques and algorithms aim to improve the performance of NUMA memory access. These access patterns, called MAP-numa (Memory Access Patterns for NUMA), currently include three classes, whose working data sets are corresponding to 1-dimension array, 2-dimension matrix and 3-dimension cube. It is dedicated for NUMA memory access optimization other than measuring the memory bandwidth and latency. MAP-numa is an alternative to those exist benchmarks such as STREAM, pChase, etc. It is used to verify the optimizations' (made automatically/manually to source code/executive binary) capacities by investigating what locality leakage can be remedied. Some experiment results are shown, which give an example of using MAP-numa to evaluate some optimizations based on Oprofile sampling. © IFIP International Federation for Information Processing 2012

MAP-numa: Access Patterns Used to Characterize the NUMA Memory Access Optimization Techniques and Algorithms

Part 5: Performance Modeling, Prediction, and TuningInternational audienceSome typical memory access patterns are provided and programmed in C, which can be used as benchmark to characterize the various techniques and algorithms aim to improve the performance of NUMA memory access. These access patterns, called MAP-numa (Memory Access Patterns for NUMA), currently include three classes, whose working data sets are corresponding to 1-dimension array, 2-dimension matrix and 3-dimension cube. It is dedicated for NUMA memory access optimization other than measuring the memory bandwidth and latency. MAP-numa is an alternative to those exist benchmarks such as STREAM, pChase, etc. It is used to verify the optimizations’ (made automatically/manually to source code/executive binary) capacities by investigating what locality leakage can be remedied. Some experiment results are shown, which give an example of using MAP-numa to evaluate some optimizations based on Oprofile sampling

Throughput Capacity of Selfish Wireless Ad Hoc Networks with General Node Density

In this paper, we study the throughput capacity of wireless networks considering the selfish feature of interaction between nodes. In our proposed network model, each node has a probability of cooperating to relay transmission. According to the extent of selfishness, we, by the application of percolation theory, construct a series of highways crossing the network. The transmission strategy is then divided into three consecutive phases. Comparing the rate in each phase, we find the bottleneck of rate is always in the highway phase. Finally, the result reveals that the node’s selfishness degrades the throughput with a factor of square root of the cooperative probability, whereas the node density has trivial impact on the throughput

Association between induced abortion and suicidal ideation among unmarried female migrant workers in three metropolitan cities in China: a cross-sectional study

Abstract Background Despite reports of mental health issues, suicidality has not been closely examined among the migrant population. The association between induced abortion and suicidal ideation is unknown among unmarried female migrant workers of reproductive age in China. This study aims to examine induced abortion and suicidality among the Chinese migrant population. Methods We recruited 5115 unmarried female migrant workers during 2015 to 2016 from Shanghai, Beijing and Guangzhou, and collected demographic, psychosocial, reproductive and mental health information using structured questionnaires. We used logistic regression models to examine the association between lifetime induced abortion and suicidal ideation during the past year among the subjects. Results Overall, 8.2% of the subjects had suicidal ideation during the past year, and 15.5% of the subjects experienced induced abortion. Induced abortion was associated with nearly twice the odds of having past-year suicidal ideation (Odds ratio, OR = 1.89; 95% confidence interval, CI: 1.46, 2.44) after adjusting for age, education, years in the working place, tobacco use, alcohol consumption, daily internet use, attitude towards premarital pregnancy, multiple induced abortion, self-esteem, loneliness, depression, and anxiety disorders. The association was stronger in those aged > 25 (OR = 3.37, 95% CI = 2.16, 5.28), with > 5 years of stay in the working place (OR = 2.98, 95% CI = 2.02, 4.39), the non-anxiety group (OR = 2.28, 95% CI = 1.74, 3.00), and the non-depression group (OR = 2.94, 95% CI = 2.08, 4.15). Conclusions Induced abortion was associated with increased odds for suicidal ideation among the unmarried female migrant workers in urban cities in China. More attention should be paid to the mental health of the population

Temperature Dependence of the Pore Structure in Polyvinylidene Fluoride (PVDF)/Graphene Composite Membrane Probed by Electrochemical Impedance Spectroscopy

In this paper, graphene was introduced in the PVDF to improve the thermal stability of the pore structure, which is the key feature for the membrane applied for the thermo-osmotic energy conversion (TOEC) process. The PVDF/graphene composite membranes were characterized by a scanning electron microscopy (SEM), a water contact angle measurement, and electrochemical impedance spectroscopy (EIS). It was found that the composite membranes exhibited improved surface hydrophobicity. Moreover, the pores in pure PVDF membrane would expand during the heat process while the existence of graphene in PVDF clearly suppressed the expansion, which implied better thermal stability of the pores in the composite membrane. According to the pore deformation time, the heat conductivities of the membranes were calculated and compared with each other. It confirmed that the composite membrane with higher graphene content exhibited enhanced heat conductivity. EIS can be used to monitor the temperature dependence of the pore structure in aqueous environments

QT dispersion failed to estimate the global dispersion of ventricular repolarization measured using monophasic action potential mapping technique in swine and patients

The aim of this study was to evaluate whether the QT dispersion measured from 12-lead electrocardiogram (ECG) can estimate the global dispersion of ventricular repolarization (DVR) measured using a monophasic action potential (MAP) mapping technique. Monophasic action potentials were recorded from 75 +/- 12 left ventricular sites in 10 pigs and from 48 +/- 16 left or right ventricular sites in 15 patients using the CARTO mapping system. The maximum DVRs in both end-of-repolarization and MAP duration among all the mapped sites were calculated and termed as global DVR for each measurement. QT intervals, QT(peak) and QT(end), were measured from the 12-lead ECG, and QT dispersions; namely the differences between the maximum and the minimum of the QTpeak and QT(end) were calculated. We found that QT dispersions were significantly smaller than (P < .05) and poorly correlated with the global DVRs both in pigs and patients. Bland-Altman agreement analysis demonstrated a marked variation of the differences and an obvious lack of agreement between the results obtained using the ECG and the MAP methods. In our patients, the global DVR increased markedly during ventricular tachycardia as compared with that during sinus rhythm (P < .05), whereas there was no significant difference in QT dispersion between these 2 subgroups. In conclusion, QT dispersion on the surface ECG could not estimate the global DVR measured using the MAP mapping technique. These findings are not consistent with some previously reported observations, suggesting the need for reappraisal of the electrophysiological implications of QT dispersion