1,721,085 research outputs found
Digital Twin-Based Real-Time Monitoring System for Safety of Multiple Laptops in Working Environment
No full textOverheating is a significant issue for laptops, especially in working environments where multiple laptops are utilized to launch heavy programs without the user's presence frequently. The proposed monitoring method is based on a digital twin (DT) system in a workstation that monitors the heat power loss of the battery, relying on the measurements of the battery current, the central processing units (CPUs) temperatures, and graphics processing units (GPUs) temperatures. Other personal computer (PC) laptops deliver their data via transmission control protocol (TCP)/Internet protocol (IP). The workstation sends a query message, allowing each PC to transfer the necessary information. The virtual system handles the received data to proceed with the alert system for warning if these parameters overcome the concerned threshold. The DT system is implemented into a Dell workstation based on MATLAB-Simulink to manage the data from ten other PCs in the experiment. Power loss is calculated in the DT Simulink system based on the electrical circuit of the PC in plugged-in mode and discharge mode. Together with other factors, the system successfully monitors and detects the current situation with a specific alert function. The monitored parameters can be observed for each setting-up period, which allows the manager to comprehend the condition state during a specific time
Power GaN FET boards thermal and electromagnetic optimization by FE modeling
Full text linkThis work deals with optimization of boards with commercial discrete power GaN FETs in applications where natural air convection is a strict constraint. In these cases, both thermal and electromagnetic behaviours are critical reliability issues for the board design, and they are modeled by Finite Element (FE) analysis, starting from literature description of the device structure, and measurements on a simple test circuit. For improved accuracy and more realistic modeling, verification and validation simulation steps are introduced, in order to evaluate the relevant error parameters for different FEM solutions. The results obtained demonstrate a good fitting with experimental and make it possible to improve board thermal characteristic. The electromagnetic simulations allow the evaluation, and possibly the reduction, of parasitic inductances for different layouts. Then, the proposed approach enables thermal and electromagnetic optimization of the layout design by simple FEM simulations, without any preliminary prototype, with time and cost saving
A Novel PIFA Antennas Design With Capacitive Load for Glacier Monitoring Applications
No full textIn glaciology, Ground Penetrating Radar (GPR) are frequently used to characterize electrical and physical properties of glaciers and snow coverages. An application is the estimation of the snow water equivalent of glaciers, coming from the knowledge of internal features of the glacier itself, such as its depth and density. For glacier monitoring, the usual frequencies space from few MHz to hundreds of MHz. Depending on the compromise between the penetration depth and the spatial resolution, the working frequency was determined. In this work, we designed, developed and measured a 300 MHz antenna used for this purpose. The shape and size were modeled in order to be used in portable systems; therefore, it was important to have light and small radiators. For this reason, we implement a novel planar inverted-F antenna (PIFA) design with capacitive load, reaching small dimensions compared to the wavelength
A wave-2-wire experimental investigation of the new "Seabreath" wave energy converter: The hydraulic response
No full textIn view of a potential design of a 2 kW small scale prototype of a wave energy converter named Seabreath, the dimensioning of the power take off, generator and relative electrical equipment is under investigation. This note presents an innovative research focusing on a holistic description of the behaviour of this device. Within a Marinet application (FP7 Research Infrastructure Action) named "Multi-chamber oscillating water column device for harvesting Ocean Renewable Energy" (MORE), electrical experiments have been carried out in the "hardware in the loop" test bench in Tecnalia laboratory, Bilbao, in order to test different control strategies. For these experiments, the Electrical and hydrodynamic response need to be fully coupled. The note describes how the available hydrodynamic model of the Seabreath has been modified to be coupled to the new electric experiments. Since the electrical tests are being used to calibrate an electrical numerical model, the procedure depicts an innovative and complete type of wave-2-wire model of a wave energy converter
Investigating failure mode and mechanism of copper ribbon interconnections in operating photovoltaic modules
No full textPhotovoltaic (PV) systems have to be designed to produce power over a long and predictable service lifetime.
This paper aims to understand what caused a PV plant’s production collapse after only two-and-a-half years of
service. An experimental examination has been carried out paying attention to the PV modules of the system.
These were found to be faulty, providing a zero voltage even in conditions of good solar irradiation. Considering the type of failure encountered, this work can be considered interesting both for the methodology applied to identify the failure mechanism and for the type of failure which is not among the most presented and discussed in the literature
Substrate Integrated Waveguide (SIW) Cavity Resonators: a Review of Technologies and Applications
No full textThis paper presents an overview of recent advances in substrate integrated waveguide (SIW) technology, with particular emphasis on different topologies and applications of SIW cavity resonators. While cavity resonators are the basic element of several RF and microwave components, SIW cavities can be implemented in a variety of ways, to optimize a given performance. This work outlines miniaturized cavities aiming at the footprint reduction, partially air-filled cavities for the implementation of SIW filters with additional transmission zeros, SIW cavities used as resonant coupling elements in the design of filters, and finally SIW cavities adopted for sensing purposes. For all these structures, a brief description of the operation principle is provided, along with the experimental verification
An electrical resistivity tomography system for imaging at laboratory scale
No full textOver the past century, there has been an increase in the use of electrical resistivity tomography in environmental research for subsurface characterization. Although commercial devices emphasize robustness and measurement quality, their lack of flexibility and high cost make them unsuitable for budget-constrained applications like research and educational purposes. This paper presents a low-cost DC resistivity meter that provides an adaptable tool for small-scale research in both laboratory and field environments. The proposed device is built around an Arduino Due board integrated with a four-channel 16-bit analog-to-digital converter. In addition, two custom shields are incorporated for signal conditioning and multiplexing. The firmware system allows users to configure key parameters, including array sequences, the number of repetitions, reverse measurements, acquisition frequency, and delays between measurements. Repetitive and reverse measurements contribute significantly to the accurate characterization of measurement errors. Its compact, cost-effective, and fully customizable design makes it particularly innovative in overcoming the limitations of current commercial alternatives. Laboratory tests validated the efficacy and reliability of the proposed device. Comparative analysis with a commercial resistivity meter (Iris Syscal R1) further reinforced these findings, revealing an excellent agreement (R2 = 0.999) between measurements acquired by the two instruments. These results highlight the system's optimal performance and the remarkable consistency of its measurements
Substrate Integrated Coaxial Line based Branch Line Coupler with Broad Out of Band Rejection
No full textThis paper reports the design and development of a miniaturized substrate integrated coaxial line (SICL) based branch line coupler operating at 5 GHz with broad out of band rejection. The proposed coupler employs a pair of center tapped unequal length open stubs to reduce the lateral footprint as well as introduce transmission zeros in the out of band region. Equations derived analytically from even and odd mode analysis aid in determining the size reduction factor as well as the position of transmission zeroes in the out of band region. A prototype of the proposed SICL based branch line coupler is fabricated and experimentally verified. The measurement results indicate low amplitude and phase imbalance less than +/- 0.5 dB and +/- 3 degrees in the range of 4.6 GHz to 5.3 GHz, contributing to a fractional bandwidth of 14.14% centered at 5 GHz. Also the proposed fully shielded and self-packaged SICL coupler features out of band rejection up to 4f(o)
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