Power Measurement

The presence of liquid refrigerant in the compressor cylinder during operation, or liquid slugging, is one of the most common causes of failure in reciprocating compressors. We propose to detect this fault by analyzing the electrical current flowing into the compressor and identifying the chan ge in the load on the motor caused by the presence of liquid in the compressor cylinder. Two different types of liquid slugging are examined in this paper. In the first, small volumes of liquid are ingested during the steady-state operation of the compressor; in the second, small volumes of liquid are present at the suction port of the compressor immediately prior to the compressor start. Experimental data from a 1-ton split air conditioning system is used to demonstrate methods for identifying these faults.

Abstract. The microwave thermal thruster heats propellant via a heat-exchanger then expands it through a rocket nozzle to produce thrust. The heat-exchanger is simply a microwave-absorbent structure through which propellant flows in small channels. Nuclear thermal thrusters are based on an analogous principle, using neutrons rather than microwaves, and have experimentally demonstrated specific impulses exceeding 850 seconds. A microwave equivalent will likely have a similar specific impulse, since both nuclear and microwave thermal thrusters are ultimately constrained by material thermal limits, rather than the energy-density limits of chemical propellants. We present the microwave thermal thruster concept by characterizing a novel variation for beamed-energy launch. In reducing the thruster concept to practice, the enabling physical process is microwave absorption by refractory materials, and we examine semiconductor and susceptor-based approaches to achieving this absorption withi...

Power Quality is the Major Concern in modern Electrical Distribution System. Supplying Un Interrupted Power to the customers is the first priority of distribution companies. In recent days, raise of un balanced loads the voltage levels are deviated, further causing many power quality issues. There is a constant need of monitoring the voltage, current levels of the distribution system. To achieve this, these parameters like voltage, current and power are continuously measured. Decomposed Signals are more effective than the Original Signals to analysis the Signal for detecting Power Quality disturbances. So, Signal Processing techniques are affective techniques to measure the voltage, current and Power. In this Paper, dual tree complex wavelets transform (DTCWT) is used to decompose the signal. A formula is proposed measure the power in distribution system using dual tree complex wavelet transform. The Proposed formula Validated by taking different cases and it is carried out in MATLAB Software.

This study investigated differences in cognitive processes related to problem complexity. It was assumed that these differences would be reflected in respondents' EEG activity--spectral power and coherence. A second issue of the study was to compare differences between the lower (alpha(1) = 7.9-10.0 Hz), and upper alpha band (alpha(2) = 10.1-12.9 Hz). In the first experiment two well-defined problems with two levels of complexity were used. Only minor differences in EEG power and coherence measures related to problem complexity were observed. In the second experiment divergent production problems resembling tasks on creativity tests were compared with dialectic problems calling for creative solutions. Differences in EEG power measures were mainly related to the form of problem presentation (figural/verbal). In contrast, coherence was related to the level of creativity needed to solve a problem. Noticeable increased intra- and interhemispheric cooperation between mainly the far distant brain regions was observed in the EEG activity of respondents while solving the dialectic problems. These results are explained by the more intense involvement of the long cortico-cortical fiber system in creative thinking. Differences between the lower and upper alpha band were significant for the power and coherence measures. In Experiment 2, fewer differences were observed in power measures in the upper alpha band than in the lower alpha band. A reverse pattern was observed for the coherence measures. These results hint to a functional independence of the two alpha bands, however, they do not allow to draw firm conclusions about their functional meanings. The study showed that it is unlikely that individuals solve well- and ill-defined problems by employing similar cognitive strategies.

Several interesting experiments in the advanced laboratory require an accurate measurement of a slowly varying, extremely small voltage. Lock-in detection is a powerful technique to recover such a signal, even in the presence of broadband noise whose magnitude is several times greater than the signal itself. We have implemented a versatile, low-cost digital lock-in analyzer completely in software. No specialized

Instrumen memegang peranan yang sangat penting dalam menentukan mutu suatu penelitian. Instrumen yang digunakan mempunyai kualitas yang memadai dalam arti valid dan reliabel maka data yang diperoleh akan sesuai dengan fakta atau keadaan sesungguhnya di lapangan[1]. Pada pengukuran besaran listrik, hal ini penting terutama pada pembangkitan kelistrikan karena mempengaruhi keselamatan baik disisi produsen maupun konsumen sistem tenaga listrik itu sendiri. Terdapat beberapa jenis alat ukur kelistrikan dengan keuntungan dan kekurangan masing-masing, Paper ini akan membahas lebih dalam mengenai alat ukur listrik Analog dengan prinsip kerja yaitu Moving Iron (Besi yang bergerak akibat gaya dari luar) dan Moving Coil (Kumparan yang bergerak akibat gaya dari luar) dan keuntungan maupun kerugian masing-masing metodenya. Dengan harapan pembaca paper ini dapat memahami dan memilih prinsip kerja yang cocok untuk melakukan pengukuran besaran listrik.

... Differences in Cognitive Processes Between Gifted, Intelligent, Creative, and Average Individuals While Solving Complex Problems: An EEG Study. Norbert Jau ovec Corresponding Author Contact Information , E-mail The Corresponding Author. ... In contrast, Marosi et al. ...

The associations among personality and psychopathology scores and individually adjusted EEG spectral power measures were investigated in 195 Ss aged 7 to 37 years. Personality was assessed in Ss older than 11 years by questionnaires based on Eysenck's and Gray's ...

In this paper, the authors present a PC-based instrument for the measurement of electrical-power quantities defined in IEEE Std. 1459. The instrument is based on a time-domain technique for the detection of the fundamental and harmonic components of voltages and currents. The time-domain strategy was originally developed by the authors for three-phase, three-wire systems. In that paper, the strategy had

In this paper, the comparison between several frequency estimation algorithms for power quality frequency assessment is shown. These include spectral, adaptive filtering, mixed time and frequency domain, least-squares and eigenvector decomposition algorithms. The different algorithms’ results are compared for three typical power measurement situations that include harmonics and noise. The main objective is to select the most promising algorithms for

The problem of Non-Instrusive Load Monitoring (NILM) is usually formulated as a single-channel blind source separation task, whose successful solution enable fast and convenient load identification and energy disaggregation. When applied at test time, NILM algorithms aim to identify the operating characteristics of individual appliances from an aggregate power measurement of the entire house. Recent advances in deep learning gave rise to many methods that mostly focus on learning a direct mapping from aggregate measurement to individual appliance power. However, these methods are not only computationally expensive, but they often suffer from overfitting and don't generalize very well. In this paper, we propose a novel NILM method that leverages advances in statistical learning that haven't been properly applied in this domain before. The proposed method consists of three stages: a) a Bayesian non-parametric learning-based approach for appliance state extraction; b) synthetic minority oversampling technique (SMOTE) for data augmentation and mitigating the heavy imbalance in switching events; and c) appliance-specific lightweight long short-term memory (LSTM) networks for status classification for each appliance. We adopt a “differential” input (the difference before and after the switching event) to reduce the complexity of network training and make the proposed method robust to multi-appliance switching events. Experiments are conducted to demonstrate the effectiveness of the proposed method, achieving superior performance when compared to recent methods. An ablation study is conducted to demonstrate the effectiveness of each module of our method. Finally, we investigate the quality of generated synthetic samples.

The purpose of this study was to determine if three minutes of petrissage and tapotement forms of massage would influence plantar flexors' flexibility, and muscle power. Nineteen participants were randomly subjected to three conditions (control and two massages) before performing two power tests. Prior to the intervention, subjects completed ankle joint flexibility assessments. The conditions were; (1) control, where subjects lay prone and had a therapist's hands resting, (2) vigorous petrissage, and (3) tapotement applied at a rate of 4Hz; all on the triceps surae. Following completion of the intervention, subjects immediately completed a post- ankle joint flexibility test, followed by a drop-jump and concentric calf raise. The power measures were; concentric peak force, rate of force development, and drop-jump height / contact time. The data showed a significant increase (p < 0.05) in ankle joint angle on the right leg and a corresponding tendency on the left. No signif...

Abstract: The wide use of wind energy in Germany results in a lot of new power system operation problems corresponding especially to the stochastic character of the wind speed and to the not controllable production of energy. The significant amount of installed wind power in the ...