scholarly journals AC characteristics of low-ohmic foil shunts influenced by eddy currents in the mounting body

2019 ◽  
Vol 8 (2) ◽  
pp. 329-333
Author(s):  
Mario Schönecker-Baußmann
Keyword(s):  
High Frequency ◽  
Eddy Currents ◽  
Industrial Applications ◽  
Calibration Standard ◽  
Current Sensing ◽  
Switch Mode ◽  
Mode Converters ◽  
Load Stability ◽  
Further Development ◽  
Shunt Impedance

Abstract. The requirements for precision current-sensing shunts are getting more sophisticated due to further development of fast switch-mode converters and other high-frequency applications. Good AC characteristics are important both for industrial applications and for calibration standard purposes. Low-ohmic foil shunts show excellent DC behavior, but the AC characteristics could be improved. The optimization of foil shunts towards better temperature independency and load stability in the range of a few parts per million per kelvin can lead to significant weaker AC performance. In this work, eddy currents in the mounting body are identified as a cause of the increasing real part of the shunt impedance at higher frequencies by means of a numerical field simulation.

Integrated Current Sensing Technique Suitable for Step-Down Switch-Mode Power Converters

2009 ◽  
Vol E92-C (10) ◽  
pp. 1299-1303
Author(s):  
Xiaojuan XIA ◽  
Liang XIE ◽  
Weifeng SUN ◽  
Longxing SHI
Keyword(s):  
Power Converters ◽  
Current Sensing ◽  
Switch Mode ◽  
Step Down

An Isolated Capacitor-Compensated Current Sensing Method for High-Frequency Resonant Converters

2019 ◽  
Vol 34 (7) ◽  
pp. 6009-6013
Author(s):  
Kangping Wang ◽  
Hongchang Li ◽  
Zheyuan Yu ◽  
Laili Wang ◽  
Xu Yang ◽  
...  
Keyword(s):  
High Frequency ◽  
Resonant Converters ◽  
Current Sensing

scholarly journals Advancing the Ultra High Frequency RFID in Industrial Applications: A Review

2021 ◽  
Vol 44 (1) ◽  
pp. 40-52
Author(s):  
Tracy Aleong ◽  
Kit Fai Pun
Keyword(s):  
Radio Frequency Identification ◽  
High Frequency ◽  
Measurement Data ◽  
Industrial Applications ◽  
Automatic Identification ◽  
Rfid Technology ◽  
Uhf Rfid ◽  
Privacy And Security ◽  
Ultra High Frequency ◽  
The Past

Radio Frequency Identification (RFID) technology transmits data wirelessly and falls under the broad classification of Automatic Identification and Data Capture (AIDC). The advances in RFID technology continue to be accepted worldwide for various tracking and monitoring type applications. This paper reviews the principle of RFID system operation using an extensive search of relevant articles from technology management and related journals, over the past two decades. It explores 1) the RFID tags operating in the ultra-high frequency (UHF) band, 2) analyses some of the major advancements of this technology in the field of sensor tagging solutions in the past two decades, and 3) discusses industry-based applications utilising UHF RFID sensor tagging solutions for process measurement data acquisition. The main challenges identified are privacy and security concerns on their applications in industry. The paper contributes to amalgamating a list of UHF RFID industry-based applications. It is expected that the findings from this review exercise would shed light on critical areas of the UHF RFID Technology.

Paper 14: Acoustic Detection of Cavitation

1966 ◽  
Vol 181 (1) ◽  
pp. 1-8 ◽  
Author(s):  
I. S. Pearsall
Keyword(s):  
High Frequency ◽  
Critical Frequency ◽  
Low Frequency ◽  
Francis Turbine ◽  
Frequency Noise ◽  
Performance Tests ◽  
Acoustic Detection ◽  
Cavitation Noise ◽  
Further Development ◽  
Onset Of Cavitation

The onset of cavitation in a hydraulic machine can be determined visually and its effect on performance by performance tests. It would be convenient to have an alternative method that required neither transparent sections nor expensive tests. Initial tests have been made measuring noise over a frequency range of 20 c/s-20 kc/s in one-third octave bands, on a number of pumps and turbines. An accelerometer attached to the casing was used. The tests indicated that, generally, the onset of cavitation was accompanied by a rise in the high-frequency noise, whilst the low-frequency noise increased as the cavitation developed. A maximum of cavitation noise was reached before the efficiency and load fell off. In some cases difficulty was experienced because blade cavitation was drowned by noise caused by other cavitation, such as the vortex in a Francis turbine. It also appears that the noise following the onset of cavitation is at the frequency which is used as a critical frequency in accelerated erosion tests. Further development of techniques is required, but the initial tests are encouraging.

scholarly journals Customizable Ceramic Nanocomposites Using Carbon Nanotubes

Molecules ◽  
2019 ◽  
Vol 24 (17) ◽  
pp. 3176
Author(s):  
Chinyere Okolo ◽  
Rafaila Rafique ◽  
Sadia Sagar Iqbal ◽  
Tayyab Subhani ◽  
Mohd Shahneel Saharudin ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Substantial Reduction ◽  
Industrial Applications ◽  
Plasma Sintering ◽  
Electrical Conductivities ◽  
Spark Plasma ◽  
Novel Strategy ◽  
Further Development ◽  
Ceramic Matrices ◽  
Ceramic Nanocomposites

A novel tweakable nanocomposite was prepared by spark plasma sintering followed by systematic oxidation of carbon nanotube (CNT) molecules to produce alumina/carbon nanotube nanocomposites with surface porosities. The mechanical properties (flexural strength and fracture toughness), surface area, and electrical conductivities were characterized and compared. The nanocomposites were extensively analyzed by field emission scanning electron microscopy (FE-SEM) for 2D qualitative surface morphological analysis. Adding CNTs in ceramic matrices and then systematically oxidizing them, without substantial reduction in densification, induces significant capability to achieve desirable/application oriented balance between mechanical, electrical, and catalytic properties of these ceramic nanocomposites. This novel strategy, upon further development, opens new level of opportunities for real-world/industrial applications of these relatively novel engineering materials.

scholarly journals Intravaginal Devices and GNSS Collars with Satellite Communication to Detect Calving Events in Extensive Beef Production in Northern Australia

2020 ◽  
Vol 12 (23) ◽  
pp. 3963
Author(s):  
Christie Pearson ◽  
Lucy Lush ◽  
Luciano A. González
Keyword(s):  
High Frequency ◽  
Satellite Communication ◽  
Satellite System ◽  
Behavioral Changes ◽  
Very High Frequency ◽  
Average Activity ◽  
Newborn Calves ◽  
Global Navigation Satellite ◽  
Further Development ◽  
Very High

Observing calves at birth may help to identify risk factors for, and reduce, calf loss in extensive beef systems. The objectives of this study were to: (1) evaluate two commercial satellite birth alert systems to enable the observation of newborn calves and (2) assess behavioral changes of cows around calving. Vaginal Implant Transmitters (VIT) paired with Global Navigation Satellite System (GNSS) collars were worn by 20 cows in Trial 1 and 10 cows in Trial 2 to identify birthing events. The VIT and GNSS collars contained a temperature sensor, accelerometer, and very high frequency (VHF) to communicate with a handheld tracker, and ultra-high frequency (UHF) for communication between the VIT and GNSS collar, which had two-way communication using Iridium satellites. A change (Brand 1) or drop (Brand 2) in temperature of more than 3 °C and inactivity triggered the VIT to communicate an expelled alert to the collar, which transmitted the birth alert information via Iridium (device ID, date, time and geolocation of the GNSS collar at expulsion). Cows and calves were tracked in the paddock following a birth alert to assess their health and status. Overall, true birth alerts occurred in only 27.6% of devices. Cows remained active on the day of calving travelling 5.54 ± 4.11 and 5.00 ± 2.80 km/day compared to 6.45 ± 2.79 and 6.12 ± 2.30 km/d on days when calving did not occur for Trial 1 and 2, respectively (mean ± SD). Average activity of the accelerometer X- and Y-axis on calving day was reduced by 15%–20% compared to other days in Trial 1 (p < 0.05) but not in Trial 2 (p > 0.05). Results suggest that these two birth alert systems are not suitable for use in extensive systems and the further development of the technology is required. Cows in the current trials remained active on the day of, and after, calving, indicating that a faster, real-time alert system and communication protocol would be required to achieve the aim of finding newborn calves.

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