rf PUMPED SQUID WITH LARGE OUTPUT SIGNAL

1991 ◽  
Vol 05 (05) ◽  
pp. 365-373 ◽  
Author(s):  
G.S. KRIVOY ◽  
V.A. KOMASHKO
Keyword(s):  
Output Signal ◽  
Weak Link ◽  
Operating Mode ◽  
Experimental Investigations ◽  
Tank Circuit ◽  
Noise Spectral Density ◽  
New Device ◽  
Rf Squids ◽  
Rf Squid ◽  
Large Output

The dc SQUID had been presented for use in the rf SQUID instead of a weak link. The new device, referred to as “double SQUID”, possesses a large output signal (hundreds of microvolts) in operating in a hysteretic mode. For making an operating mode a double SQUID is coupled to a circuit traditional for rf SQUIDs containing a tank circuit and an rf current pumping generator. The magnetic flux being measured is recognized by the dc SQUID quantization loop which results in changing its critical current. As a result the height of the flat part of the tank circuit I–V characteristics coupled to a double SQUID is modulated. It is this modulation that is the SQUID output signal. The experimental investigations of the double SQUID showed the validity of the assumptions under consideration. Output signals up to 690 μV, noise spectral density ≈2×10−5ϕ0/ Hz 1/2 (ϕ0 is the flux quantum) and energy resolution ≈1.4×10−29 J/Hz have been obtained.

scholarly journals Experimental Evaluation of Airlift Performance for Vertical Pumping of Water in Underground Mines

2021 ◽  
Author(s):  
Parviz Enany ◽  
Oleksandr Shevchenko ◽  
Carsten Drebenstedt
Keyword(s):  
Water Flow ◽  
High Efficiency ◽  
Experimental Studies ◽  
Theoretical Models ◽  
Injection System ◽  
Experimental Investigations ◽  
Flow Mode ◽  
New Device ◽  
Riser Pipe ◽  
Airlift Pump

AbstractThis paper presents experimental studies on the optimization of air–water flow in an airlift pump. Airlift pumps use compressed gas to verticall transport liquids and slurries. Due to the lack of theoretical equations for designing and predicting flow regimes, experimental investigations must be carried out to find the best condition to operate an airlift pump at high efficiency. We used a new air injection system and different submergence ratios to evaluate the output of a simple pump for vertical displacement of water in an underground mine. The tests were carried out in a new device with 5.64 m height and 10.2 cm circular riser pipe. Three air-jacket pipes, at different gas flows in the range of 0.002–0.09 m3/s were investigated with eight submergence ratios. It was found that with the same air flow rate, the most efficient flow of water was achieved when an air jacket with 3 mm diameter holes was used with a submergence ratio between 0.6 and 0.75. In addition, a comparison of practical results with two theoretical models proposed by other investigators showed that neither was able to accurately predict airlift performance in air–water flow mode.

Influence of Material and Geometry of the Dielectric on the Characteristics of the Tank Circuit Resonators for High-Tc RF-SQUID-Based System

2016 ◽  
Vol 26 (3) ◽  
pp. 1-5 ◽  
Author(s):  
Nafise Kalantari ◽  
Faezeh Shanehsazzadeh ◽  
Farrokh Sarreshtedari ◽  
Mehdi Fardmanesh
Keyword(s):  
Tank Circuit ◽  
High Tc ◽  
Rf Squid

CMOS Active Inductor/Resonator Based Voltage Controlled Oscillator

2019 ◽  
Vol 12 (6) ◽  
pp. 500-506 ◽  
Author(s):  
Dhara P. Patel ◽  
Shruti Oza-Rahurkar
Keyword(s):  
Phase Noise ◽  
Output Power ◽  
Output Signal ◽  
Active Inductor ◽  
Voltage Controlled Oscillator ◽  
High Output Power ◽  
Tank Circuit ◽  
Chip Area ◽  
Lc Resonator ◽  
High Output

Background: A tunable CMOS active inductor/resonator based Voltage Controlled Oscillator (VCO) has been presented. In the design of LC-VCO, LC resonator (tank) circuit has been substituted with gyrator based CMOS active inductor/resonator. The purity of VCO output signal is defined by the phase noise parameter. Methods: For good spectral purity of VCO output signal, the phase noise should be minimum. Moreover, the quality factor of LC resonator is inversely proportional to the phase noise of VCO output signal. In the presented work, a high-quality active inductor/resonator circuit has been used to design VCO which minimizes the phase noise and chip area as well. Further, other VCO characterization factors are measured. Results: The designed circuit has been implemented in 0.18µm CMOS technology. Conclusion: The design of the proposed AI based voltage controlled oscillator shows better phase noise, less chip area and high output power. The high output power is achieved at the cost of limited tuning range of 1.14 GHz ~ 2.1 GHz. The presented active inductor based voltage controlled oscillator can be used for RF applications from 1.14GHz ~ 2.1GHz.

scholarly journals Deep ocean wave energy systems (DOWES): experimental investigations

2014 ◽  
Vol 11 (2) ◽  
pp. 139-146 ◽  
Author(s):  
Srinivasan Chandrasekaran ◽  
Deepak C Raphel ◽  
Sai Shree
Keyword(s):  
Wave Energy ◽  
Energy Systems ◽  
Deep Ocean ◽  
Ocean Waves ◽  
Offshore Structures ◽  
Green Energy ◽  
Experimental Investigations ◽  
Energy Devices ◽  
New Device ◽  
Operational Energy

Deep water offshore structures have access to very powerful ocean waves by virtue of their location and site condition. Should the energy possessed by these waves be harnessed, it can be one of the popular green energy systems. Present study aims at the design and development of a new device that can be fitted on an offshore semisubmersible platform and can produce electricity to meet their operational energy demands partially. Few wave energy devices are developed in the recent past; Common idea in all such devices is that they harness heave, or surge energy of the wave. In the present study, heave energy of the buoy is converted to mechanical work by deploying hydraulic cylinders and a motor. The generated power from the waves shall be primarily utilized in the semi-submersible platform for deep sea mining application.DOI: http://dx.doi.org/10.3329/jname.v11i2.18420

scholarly journals Close-to-Application Test Methodology Validated by a Baseline Study for Novel Bearing Developments in Aircraft Turbines

Lubricants ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 7
Author(s):  
Philipp Renhart ◽  
Florian Summer ◽  
Florian Grün ◽  
Andreas Eder
Keyword(s):  
Journal Bearings ◽  
Ex Situ ◽  
Experimental Investigations ◽  
Operational Conditions ◽  
New Device ◽  
New Methods ◽  
Test Methodology ◽  
Test Strategies ◽  
Aircraft Application

The main objective of the present paper is the validation of new methods concerning experimental investigations of journal bearings under ordinary and extraordinary operational conditions. Derived results should facilitate the determination of damage mechanisms and a qualitative ranking for a prospective coating development. Prior investigated scenarios like start/stop and emergency running behavior were extended by starved and unlubricated experiments for an aircraft application. Focusing on thermal stability and reproducibility, two new subscale test strategies were developed derived from generalized operational conditions of journal bearings. For an improved ex-situ wear measurement of bearing shells, a new device was developed successfully. The results showed that the newly designed test methodologies are suitable to investigate unlubricated coatings leading to conclusive and repetitive results.

scholarly journals Transformer Coupling and Its Modelling for the Flux-Ramp Modulation of rf-SQUIDs

Instruments ◽  
2018 ◽  
Vol 3 (1) ◽  
pp. 3 ◽  
Author(s):  
Paolo Carniti ◽  
Lorenzo Cassina ◽  
Marco Faverzani ◽  
Elena Ferri ◽  
Andrea Giachero ◽  
...  
Keyword(s):  
Electromagnetic Interference ◽  
Quantum Interference ◽  
Signal Reconstruction ◽  
Transition Edge Sensors ◽  
Open Loop ◽  
Inductively Coupled ◽  
Transition Edge ◽  
Rf Squids ◽  
Rf Squid

Microwave SQUID (Superconducting QUantum Interference Device) multiplexing is a suitable technique for reading a large number of detector channels, using only a few connecting lines. In the HOLMESexperiment, this is based on inductively coupled rf-SQUIDs fed by TES (Transition Edge Sensors). Operation of the whole rf-SQUID chain is achieved with a single transmission line, by means of the recently introduced flux-ramp modulation technique—a sawtooth signal which allows signal reconstruction while operating the rf-SQUIDs in an open loop condition. Due to the crucial role of the sawtooth signal, it is very important that it does not suffer from ground-loop disturbances and electromagnetic interference (EMI). Introducing a transformer between the sawtooth source and the SQUID is very effective in suppressing disturbances. The sawtooth signal has both slow and fast components, and the frequency can vary between a few kHz up to a MHz, depending on the TES signal and SQUID characteristics. A transformer able to handle such a broad range of conditions must have very stringent characteristics and needs to be custom designed. Our solution exploits standard commercial and inexpensive transformers for LAN networks, stacked in a user-selectable number, to better fit the bandwidth requirements. A model that allows handling of the low- and high-frequency operating range has been developed.

Integrated Monolayer Planar Flux Transformer and Resonator Tank Circuit for High- $T_{c}$ RF-SQUID Magnetometer

2017 ◽  
Vol 27 (4) ◽  
pp. 1-4 ◽  
Author(s):  
Faezeh Shanehsazzadeh ◽  
Tahereh Jabbari ◽  
Fatemeh Qaderi ◽  
Mehdi Fardmanesh
Keyword(s):  
Squid Magnetometer ◽  
Tank Circuit ◽  
Rf Squid

scholarly journals Performance of a 2048 × 2048 Pixel Three-Side-Buttable CCD Designed for Large Focal Planes in Astronomy

1995 ◽  
Vol 167 ◽  
pp. 295-296
Author(s):  
J. A. Cortiula
Keyword(s):  
Conversion Factor ◽  
Event Rate ◽  
Operating Mode ◽  
Packaging Material ◽  
Low Noise ◽  
Low Power Consumption ◽  
New Device ◽  
On Chip ◽  
Specific Care ◽  
Better Than

TH78997M is a 2048 × 2048 pixel full-frame CCD sensor featuring 15 × 15 micron pixels, MPP operating mode, four parallel outputs and buttability on three sides. This new device makes it possible to build very large focal plane detectors for telescopes (two × n butted CCDs) with less than a 25 dead pixel zone between adjacent sensors. Other features are high full-well capacity (typically 180 Ke−) and very low dark current thanks to four phase MPP clocking which allows a very long exposure time together with a high S/N ratio.The readout of a complete frame is achieved through four parallel outputs running at frequencies ranging from ten KHz up to five MHz per output. The four on-chip amplifiers have been designed to be completely user controlled and to meet most of terrestrial and spaceborne astronomy requirements: very low noise (less than 4e− at 50 KHz, −40 degrees C), very low power consumption (150 micro-W/amplifier at 10 KHz/output), linearity better than 0.5% together with high conversion factor (4.2 micro-V/e−) over 2.5 V output range. The packaging of the device is compatible with the good flatness of the chip and with the low parasitic “cosmic event” rate thanks to specific care in selecting the packaging material.

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