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Laboratory Experiments
Published in Francis S. Tse, Ivan E. Morse, Measurement and Instrumentation in Engineering, 2018
The current I2 ≃ 0, because the op-amp has a high input impedance. Since V+ is at ground potential and V+ ≃ V−, Va is a “virtual” ground (i.e., node a is almost at the ground potential but is not connected to ground). From Eq. E7-9 we get the basic op-amp equation () Vi−0R1=0−VoRforVoVi=−RfR1
Continuous Overcast Daylight Autonomy (DAo.con): A New Dynamic Metric for Sensor-Less Lighting Smart Controls
Published in LEUKOS, 2023
Ignacio Acosta, Miguel Ángel Campano, Samuel Domínguez-Amarillo, Jaime Navarro Casas
The ability of the cloud layer to transmit the luminous flux of the Sun can be expressed through the relationship between diffuse and extraterrestrial illuminance (DV/EV). This quotient is not easy to quantify, since it depends on many factors, such as the luminous turbidity and the thickness of the cloud layer (Kittler and Darula 2001). Extraterrestrial illuminance depends on a constant value of 133.8 klx and the amount on the Earth’s surface varies according to solar elevation. However, the diffuse sky illuminance can only be determined through statistical measurements. As concluded by Kittler et al. (Kittler and Darula 2017) after a five-year campaign, the most probable ratio between diffuse and extraterrestrial illuminance converges to 0.1 for sky type 1, that is to say, under ideal overcast conditions and even while the range is approximately between 0.05 and 0.2. Accordingly, the lower the diffuse to extraterrestrial ratio of illuminance, the more conservative the calculation process. For a practical approach, locations with an average overcast sky with a low or medium thickness of the cloud layer can correspond to a DV/EV equal to 0.15, while locations with an average cloudy sky with a thick cloud layer can correspond to a DV/EV equivalent to 0.05.
Linear stability analysis of a high-speed rail vehicle concerning suspension parameters variation and active control
Published in Vehicle System Dynamics, 2022
Huailong Shi, Jing Zeng, Sheng Qu
In the sky-hook damping control algorithm, the control force on the bogie can be calculated through F = −csky·vbx, in which csky refers to the damping coefficient, and vbx represents the longitudinal velocity resulting from the yaw motion of the bogie. In this section, we take kpx = 17.5 MN/m concerning the possibility of bogie hunting occurring. As in Figure 19, the modal frequency of the carbody suspension modes remains unchanged, but the frequency of the hunting mode drops a bit with csky. In addition, the damping ratio of the lower- and upper-centre roll modes remains 15% and 10% respectively. Whereas the modal damping of yaw mode drops from around 30% to 20% with csky at a speed below 300 km/h. However, csky can significantly rise the modal damping of the hunting mode, and a minimum of 400 kN·s/m is suggested in both small and large conicity cases to keep the damping ratio above 5% at a running speed up to 600 km/h. Unlike the effect of the passive yaw damper illustrated in Figure 16 and Figure 18, a large damping coefficient of AYD would not decrease the linear critical speed.
Millimeter-Wave in the Face of 5G Communication Potential Applications
Published in IETE Journal of Research, 2022
Nazih Khaddaj Mallat, Madeeha Ishtiaq, Ateeq Ur Rehman, Amjad Iqbal
The Federal Communication Commission (FCC) has allocated an unlicensed 60-GHz band also called v band, which allows the researchers to utilize the spectrum band (5 GHz). Following that, energy propagation has unique characteristics that ensure many other advantages such as excellent immunity to interference, high security, and the possibility of frequency-reuse [36–38]. The V-band mmWave spectrum exploits an attractive resource for the wireless industry (high-speed indoor communications and short distance high-resolution radar sensor) because of its high atmospheric oxygen losses. The atmospheric losses of 10–15 dB/km make the band inconvenience for long-range (> 2 km) and suitable for short-range (< 1 km) communications. Some of the most important applications provided by the V-band include; high-definition video transmission, file transfer at gigabits per second, wireless gigabit Ethernet, and short communications between building, within an office and home (indoor).