A Cost-Effective Method for Power Factor ‎Metering Systems ‎

The power factor (PF) is an important measurement in an AC electrical system that indicates how much power ‎is utilized to accomplish productive work by a load and how much power is consumed. As a result, it\u27s one of ‎the primary causes of excessive energy costs and power outages. This paper aims to present a simple, cost-‎effective, and accurate PF metering and monitoring system implemented using an Arduino microcontroller with ‎a novel methodology different from other papers. The proposed method is to design the software code instead ‎of using external components of Zero-Crossing Detectors (Z-CDs) for both voltage (V) and current (I) signals, and ‎instead of using Exclusive-OR (X-OR) gates also. Determining the phase-angle and PF in an efficient manner ‎can be useful in many approaches to electrical systems: 1-for synchronization of parallel connections of ‎alternators; 2-for directional protection systems; 3-for PF correction and load management; and 4-for designing ‎watt/energy meters. Using the Proteus 8 Professional (ISIS program), the proposed designed circuit was ‎simulated for more verification. The simulation and experimental findings are presented to validate the ‎proposed metering system\u27s effectiveness.

Limitation in thin-film detection with transmission-mode terahertz time-domain spectroscopy

In transmission-mode terahertz time-domain spectroscopy (THz-TDS), the thickness of a sample is a critical factor that determines an amount of the interaction between terahertz waves and bulk material. If the interaction length is too small, a change in the transmitted signal is overwhelmed by fluctuations and noise in the system. In this case, the sample can no longer be detected. This article presents a criterion to determine the lower thickness boundary of a free-standing film that can still be detectable by free-space transmission-mode THz-TDS. The rigorous analysis yields a simple proportional relation between the sample optical length and the system SNR. The proposed criterion can help to decide whether an alternative terahertz thin-film sensing modality is necessary.Comment: 5 pages, 1 figur

Terahertz Faraday rotation in a magnetic liquid: High magneto-optical figure of merit and broadband operation in a ferrofluid

We report on the demonstration of a high figure of merit (FOM) Faraday rotation in a liquid in the terahertz (THz) regime. Using a ferrofluid, a high broadband rotation (11 mrad/mm) is experimentally demonstrated in the frequency range of 0.2–0.9 THz at room temperature. Given the low absorption of the liquid, a high magneto-optical figure of merit (5-16 rad.cm/T) is obtained