Investigation and Control of Backflow Ahead of a Shrouded Inducer

1998 ◽  
Vol 120 (3) ◽  
pp. 549-555
Author(s):  
C. Offtinger Brissaud ◽  
C. Henry ◽  
R. Morel ◽  
F. Spettel
Keyword(s):  
Adverse Effects ◽  
Experimental Results ◽  
Pressure Pulsations ◽  
Pump Performance ◽  
Part Load ◽  
Simple Geometry ◽  
And Control

Incorporating a backflow recirculator is a way to reduce part load instabilities of inducers. Experimental results demonstrate that two devices with simple geometry considerably soften pressure pulsations in suction and discharge pipes associated with part load instabilities, even at low NPSH conditions and low flowrates. This is accomplished with negligible adverse effects on pump performance.

Nature and Origin of Micropollutants

1982 ◽  
Vol 14 (12) ◽  
pp. 5-14 ◽  
Author(s):  
D Mackay
Keyword(s):  
Adverse Effects ◽  
Toxicity Data ◽  
Low Level ◽  
Environmental Models ◽  
Toxic Event ◽  
And Control

The origins of “micropollutants” are discussed and classified. It is suggested that assessing the risk and ensuring an acceptably low level of adverse effects from these substances requires information or control of three factors (exposure, toxicity and characteristics of the victim or organism) which combine to generate the toxic event. Methods of estimating exposure are discussed, especially environmental models. Ultimately, it should be possible to couple these models to toxicity data in a rational, rigorous manner to elucidate the extent of risk and control it to acceptable levels.

EXPERIMENTAL RESULTS ON COMMAND AND CONTROL OF UNMANNED AIR VEHICLE SYSTEMS

2007 ◽  
Vol 40 (15) ◽  
pp. 239-244 ◽  
Author(s):  
Pedro Almeida ◽  
Ricardo Bencatel ◽  
Gil M. Gonçalves ◽  
JoãTo Borges Sousa ◽  
Christoph Ruetz
Keyword(s):  
Command And Control ◽  
Experimental Results ◽  
Unmanned Air Vehicle ◽  
Air Vehicle ◽  
Vehicle Systems ◽  
And Control

Damping of Self-Excited Pressure Pulsations in Petrodiesel Pipeline

2014 ◽  
Vol 630 ◽  
pp. 375-382 ◽  
Author(s):  
Daniel Himr ◽  
Vladimir Haban
Keyword(s):  
Hydraulic System ◽  
Check Valve ◽  
Control Valve ◽  
Sampling Frequency ◽  
Pressure Pulsations ◽  
One Dimensional ◽  
Fuel Storage ◽  
Excited Oscillation ◽  
Subsequent Measurement ◽  
And Control

A pumping station in a fuel storage suffered from pressure pulsations in a petrodiesel pipeline. Check valves protecting the station against back flow made a big noise when disc hit a seat. Due to employees complaints we were asked to solve the problem, which could lead to serious mechanical problems. Pressure measurement in the pipeline showed great pulsations, which were caused by self-excited oscillation of control valves at the downstream end of pipeline. The operating measurement did not catch it because of too low sampling frequency. One dimensional numerical model of the whole hydraulic system was carried out. The model consisted of check valve, pipeline and control valve, which could oscillate, so it was possible to simulate the unsteady flow. When the model was validated, a vessel with nitrogen was added to attenuate pressure pulsations. According to the results of numerical simulation, the vessel was installed on the location. Subsequent measurement proved noticeably lower pulsations and almost no noise.

Effect of Ultrasound on the Fetus

1987 ◽  
Vol 8 (8) ◽  
pp. 228-253
Keyword(s):  
Adverse Effects ◽  
Human Fetus ◽  
Matched Control ◽  
Subsequent Development ◽  
Childhood Malignancy ◽  
Ultrasonic Examination ◽  
The United Kingdom ◽  
Dna Alterations ◽  
And Control

The question of adverse effects of ultrasonic examination upon the human fetus continues to be explored. The impetus for these investigations comes from animal or in vitro cellular studies showing a reduction of weight and size and DNA alterations in mice litters exposed to ultrasound. Human studies to date have failed to reveal any comparable results. These two articles explore whether there is a positive correlation between fetal ultrasonic examination and/or monitoring and subsequent development of childhood malignancy. The first study reports comparison of histories from 1,731 children who died of cancer in the United Kingdom between 1972 and 1981 with age-matched control children for exposure. Six percent of both case and control children had had ultrasonic exposure.

Modeling, parameter identification, guidance and control of an unmanned surface vehicle with experimental results

2021 ◽  
Vol 241 ◽  
pp. 110038
Author(s):  
Helmi Abrougui ◽  
Samir Nejim ◽  
Saber Hachicha ◽  
Chiheb Zaoui ◽  
Habib Dallagi
Keyword(s):  
Parameter Identification ◽  
Experimental Results ◽  
Unmanned Surface Vehicle ◽  
Guidance And Control ◽  
And Control

Analysis and Design of Hardware Architectures and Control Algorithms for an EPAC

2010 ◽  
Author(s):  
Simone Formentin ◽  
Giovanni Alli ◽  
Sergio M. Savaresi ◽  
Francesco Castelli Dezza
Keyword(s):  
Health Service ◽  
Energy Cost ◽  
Optimal Choice ◽  
Experimental Results ◽  
Control Algorithms ◽  
Analysis And Design ◽  
Electric Bicycle ◽  
Hardware Architectures ◽  
And Control

EPACs (Electric Pedal Assisted Cycles) represent a very efficient and fashionable mean of non-polluting transport. They are useful for bringing education, for health service and they guarantee the lowest energy cost per distance traveled. In this paper, a power kit has been designed and implemented on a real electric bicycle. In particular, hardware architectures and control algorithms are developed together, taking in account shared needs. An optimal choice of the components and an innovative overboost strategy characterize the provided system. Experimental results and comparison with a benchmark product available in the market demonstrate the efficiency of the whole system.

scholarly journals A Time Domain Passivity Control Scheme for Bilateral Teleoperation

Electronics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 325 ◽  
Author(s):  
Long Sheng ◽  
Usman Ahmad ◽  
Yongqiang Ye ◽  
Ya-Jun Pan
Keyword(s):  
Time Domain ◽  
Parametric Design ◽  
Switching Time ◽  
Experimental Results ◽  
Division Problem ◽  
Bilateral Teleoperation ◽  
Safe Operation ◽  
Guaranteed Stability ◽  
Control Scheme ◽  
And Control

Conventional time domain passivity control inevitably embodies division. Zero division can occur under a tiny force or velocity, which may be inevitable, and will be the cause of control crash. To avoid the zero division problem and control crash, we propose a switching dissipation controller for guaranteed stability. The parametric design of the proposed approach is discussed. The switching time domain passivity control is then applied to teleoperation and safe operation is achieved. Simulation and experimental results are demonstrated to validate the effectiveness of the proposed control scheme.

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