scholarly journals A Novel Servovalve Pilot Stage Actuated by a Piezo-electric Ring Bender: A Numerical and Experimental Analysis

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 671 ◽  
Author(s):  
Paolo Tamburrano ◽  
Andrew R. Plummer ◽  
Pietro De Palma ◽  
Elia Distaso ◽  
Riccardo Amirante
Keyword(s):  
Power Consumption ◽  
Motion Control ◽  
Response Speed ◽  
High Accuracy ◽  
Main Stage ◽  
Speed Of Response ◽  
Opening And Closing ◽  
The Cost ◽  
Very High ◽  
Piezo Electric

Electrohydraulic servovalves are widely used for precise motion control in aerospace and other industries due to their high accuracy and speed of response. However, commercial two-stage servovalves have several undesirable characteristics, such as the power consumption caused by the quiescent flow (internal leakage) in the pilot stage, and the complexity and high number of parts of the torque motor assembly, which affect the cost and the speed of manufacture. The solution to these problems can help to reduce costs, weight and power consumption, and enhance the reliability and reproducibility as well as the performance of these valves. For these reasons, this paper proposes a novel configuration for the pilot stage: it is composed of two normally closed two-way two-position (2/2) valves actuated by two piezo-electric ring benders; the opening and closing of the two piezo-valves can generate a differential pressure to be used to control the displacement of the main spool. In this way, there is negligible quiescent flow when the main stage is at rest; in addition, the torque motor and all its components are removed. To assess the performance of this novel pilot stage concept, a prototype of the piezo-valve has been constructed and tested. The experimental results indicate that the response speed of the new piezo-valve is very high. Furthermore, a numerical model is employed to show that, by adjusting specific parameters, the performance of the piezo-valve can be further improved, so that the valve can be fully opened or closed in less than 5 ms.

scholarly journals Analysis of Three Different Kalman Filter Implementations for Agricultural Vehicle Positioning

2009 ◽  
Vol 3 (1) ◽  
pp. 13-19 ◽  
Author(s):  
M. Rodríguez ◽  
J. Gómez
Keyword(s):  
Kalman Filter ◽  
Kinematic Model ◽  
High Accuracy ◽  
Vehicle Model ◽  
Gps Receivers ◽  
Autonomous Guidance ◽  
Agricultural Vehicle ◽  
Vehicle Positioning ◽  
The Cost ◽  
Very High

Conventional positioning techniques based on GPS receivers are not accurate enough to be used with autonomous guidance systems. High accuracy GPS receivers can be employed, but the cost of the system would be very high. The alternative solution presented in this article is to combine the data provided by different positioning sensors using a Kalman filter. The described procedure also uses an odometric estimation of the mobile position, based on the kinematic model of the agricultural vehicle. Three different implementations of the Kalman filter are described, using different sensor combinations but based on the same vehicle model.

scholarly journals Decrease of Power Consumption Utilizing IOT

2019 ◽  
Vol 9 (1) ◽  
pp. 5316-5319
Keyword(s):  
Internet Of Things ◽  
Power Consumption ◽  
Smart Cities ◽  
Electricity Consumption ◽  
Cost Of Electricity ◽  
Future Consumption ◽  
The Cost ◽  
Very High ◽  
New System ◽  
Made In

As electricity consumption is very high so using IOT ,reduction of electricity consumption is tried company nowadays but the use of it in extreme levels results as a damage to environment and personal financial conditions.Involving fields of application and Internet of things sensors are made. In this paper an architecture is introduced, that helps the smart cities to save resources for future. Consumption of electricity in a way is destroying the environment so this paper helps in saving the cost of electricity as well as saving the environment using wireless connections. Finally a new system is proposed keeping in mind the old one and its challenges. This system overcomes all the challenges and difficulties faced by the old one. To implement the framework electrical appliances such as lights, fans, ac etc are incorporated within the proposed system of reduction of electricity consumption

scholarly journals Multilevel Monte Carlo methods

Acta Numerica ◽  
2015 ◽  
Vol 24 ◽  
pp. 259-328 ◽  
Author(s):  
Michael B. Giles
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Methods ◽  
Low Cost ◽  
Computational Cost ◽  
High Accuracy ◽  
Stochastic Pdes ◽  
Multilevel Monte Carlo ◽  
The Cost ◽  
Multilevel Monte Carlo Method ◽  
Very High

Monte Carlo methods are a very general and useful approach for the estimation of expectations arising from stochastic simulation. However, they can be computationally expensive, particularly when the cost of generating individual stochastic samples is very high, as in the case of stochastic PDEs. Multilevel Monte Carlo is a recently developed approach which greatly reduces the computational cost by performing most simulations with low accuracy at a correspondingly low cost, with relatively few simulations being performed at high accuracy and a high cost.In this article, we review the ideas behind the multilevel Monte Carlo method, and various recent generalizations and extensions, and discuss a number of applications which illustrate the flexibility and generality of the approach and the challenges in developing more efficient implementations with a faster rate of convergence of the multilevel correction variance.

scholarly journals A new form of interferometer

1922 ◽  
Vol 100 (705) ◽  
pp. 419-423 ◽  
Keyword(s):  
Free Surface ◽  
Parallel Plate ◽  
High Accuracy ◽  
Resolving Power ◽  
Plane Parallel Plate ◽  
Transparent Liquid ◽  
Series Of Experiments ◽  
New Form ◽  
The Cost ◽  
Very High

The Lummer and Gehrke interferometer consists of a thin plate of glass with its two surfaces worked optically true and paralled to one another. High accuracy is required in the plane parallelism, and the flatness of surface and the difficulty of working such long plates for high resolving powers, and the cost- involved, sets a limit to our achievement in this direction. Such plates, even when finished, furnish results which have given rise to a considerable amount of discussion and raise doubt as to whether the appearances are trustworthy at such high resolving powers and whether they are not partly due to ghosts formed by the defects in the glass. Hence the present attempt to devise a parallel plate that would meet these objections and serve as an instrument of resolving power and precision sufficient to extend our knowledge of the constitution of spectrum lines, and a variety of other phenomena requiring the aid of very high resolving power. The late Lord Rayleigh used the free surface of a sheet of water as a true optical flat for testing plane surfaces, and describes the results of observations of interference with large differences of path between two interfering beams in a thick slab of water floating on mercury. The optical flatness of the surface of a liquid at rest suggests that, by floating a layer of water or other transparent liquid over another, like mercury, with which it does not mix, we can get an optically perfect plane parallel plate, of any length and thickness, which may be used as a parallel-plate interferometer. The following is a brief account of the results of a series of experiments, conducted under great experimental difficulties during 1918-1919, to test the practicability of this idea.

Consistency of Cognitive and Motor Performance Measures over Two Years in Reading Retarded Children

1980 ◽  
Vol 50 (3_suppl) ◽  
pp. 1059-1065 ◽  
Author(s):  
M. G. Aman ◽  
J. M. Mayhew
Keyword(s):  
Response Time ◽  
Response Speed ◽  
Cognitive Testing ◽  
Initial Contact ◽  
Temporal Dimension ◽  
Speed Of Response ◽  
Reliability Estimates ◽  
High Consistency ◽  
Moderate Range ◽  
Very High

Children identified for specific reading retardation were tested at initial contact and after 2 yr. on a variety of measures including seat activity, and cognitive and motor steadiness tasks. Developmentally there were few improvements on the accuracy and response time measures, whereas response speed and motor steadiness improved substantially with maturation. Consistency of performance over the 2 yr. showed the following pattern. Correlations for accuracy and response time were generally around chance levels, whereas the predictive validity for seat movement was in the low to moderate range. Speed of response and motor steadiness showed moderate to very high consistency over the 2 yr. Reliability estimates at each test interval were generally high for all variables except accuracy. These results suggest that there may be an advantage in adopting speed measures in preference to response time, and they also highlight the importance of the temporal dimension in cognitive testing.

scholarly journals Stellar magnetic imaging from spectropolarimetric data

1996 ◽  
Vol 176 ◽  
pp. 53-60 ◽  
Author(s):  
J.-F. Donati
Keyword(s):  
Small Amplitude ◽  
High Accuracy ◽  
Spectral Lines ◽  
New Method ◽  
Doppler Imaging ◽  
Magnetic Imaging ◽  
Active Stars ◽  
Surface Fields ◽  
Very High

In this paper, I will review the capabilities of magnetic imaging (also called Zeeman-Doppler imaging) to reconstruct spot distributions of surface fields from sets of rotationnally modulated Zeeman signatures in circularly polarised spectral lines. I will then outline a new method to measure small amplitude magnetic signals (typically 0.1% for cool active stars) with very high accuracy. Finally, I will present and comment new magnetic images reconstructed from data collected in 1993 December at the Anglo-Australian Telescope (AAT).

scholarly journals CFD Simulation of a Hyperloop Capsule Inside a Low-Pressure Environment Using an Aerodynamic Compressor as Propulsion and Drag Reduction Method

2021 ◽  
Vol 11 (9) ◽  
pp. 3934
Author(s):  
Federico Lluesma-Rodríguez ◽  
Temoatzin González ◽  
Sergio Hoyas
Keyword(s):  
Shock Waves ◽  
Power Consumption ◽  
High Speed ◽  
Cfd Simulation ◽  
Aerodynamic Drag ◽  
Flow Behavior ◽  
Critical Conditions ◽  
Vehicle Speed ◽  
Blockage Ratio ◽  
The Cost

One of the most restrictive conditions in ground transportation at high speeds is aerodynamic drag. This is even more problematic when running inside a tunnel, where compressible phenomena such as wave propagation, shock waves, or flow blocking can happen. Considering Evacuated-Tube Trains (ETTs) or hyperloops, these effects appear during the whole route, as they always operate in a closed environment. Then, one of the concerns is the size of the tunnel, as it directly affects the cost of the infrastructure. When the tube size decreases with a constant section of the vehicle, the power consumption increases exponentially, as the Kantrowitz limit is surpassed. This can be mitigated when adding a compressor to the vehicle as a means of propulsion. The turbomachinery increases the pressure of part of the air faced by the vehicle, thus delaying the critical conditions on surrounding flow. With tunnels using a blockage ratio of 0.5 or higher, the reported reduction in the power consumption is 70%. Additionally, the induced pressure in front of the capsule became a negligible effect. The analysis of the flow shows that the compressor can remove the shock waves downstream and thus allows operation above the Kantrowitz limit. Actually, for a vehicle speed of 700 km/h, the case without a compressor reaches critical conditions at a blockage ratio of 0.18, which is a tunnel even smaller than those used for High-Speed Rails (0.23). When aerodynamic propulsion is used, sonic Mach numbers are reached above a blockage ratio of 0.5. A direct effect is that cases with turbomachinery can operate in tunnels with blockage ratios even 2.8 times higher than the non-compressor cases, enabling a considerable reduction in the size of the tunnel without affecting the performance. This work, after conducting bibliographic research, presents the geometry, mesh, and setup. Later, results for the flow without compressor are shown. Finally, it is discussed how the addition of the compressor improves the flow behavior and power consumption of the case.

scholarly journals Cost per DALY averted in low, middle- and high-income countries: evidence from the global burden of disease study to estimate the cost-effectiveness thresholds

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Rajabali Daroudi ◽  
Ali Akbari Sari ◽  
Azin Nahvijou ◽  
Ahmad Faramarzi
Keyword(s):  
Cost Effectiveness ◽  
Inverse Correlation ◽  
Gdp Per Capita ◽  
Middle Income ◽  
Capita Health Expenditure ◽  
Per Capita ◽  
Healthcare Interventions ◽  
Disease Study ◽  
The Cost ◽  
Very High

Abstract Background Determining the cost-effectiveness thresholds for healthcare interventions has been a severe challenge for policymakers, especially in low- and middle-income countries. This study aimed to estimate the cost per disability-adjusted life-year (DALY) averted for countries with different levels of Human Development Index (HDI) and Gross Domestic Product (GDP). Methods The data about DALYs, per capita health expenditure (HE), HDI, and GDP per capita were extracted for 176 countries during the years 2000 to 2016. Then we examined the trends on these variables. Panel regression analysis was performed to explore the correlation between DALY and HE per capita. The results of the regression models were used to calculate the cost per DALY averted for each country. Results Age-standardized rate (ASR) DALY (DALY per 100,000 population) had a nonlinear inverse correlation with HE per capita and a linear inverse correlation with HDI. One percent increase in HE per capita was associated with an average of 0.28, 0.24, 0.18, and 0.27% decrease on the ASR DALY in low HDI, medium HDI, high HDI, and very high HDI countries, respectively. The estimated cost per DALY averted was $998, $6522, $23,782, and $69,499 in low HDI, medium HDI, high HDI, and very high HDI countries. On average, the cost per DALY averted was 0.34 times the GDP per capita in low HDI countries. While in medium HDI, high HDI, and very high HDI countries, it was 0.67, 1.22, and 1.46 times the GDP per capita, respectively. Conclusions This study suggests that the cost-effectiveness thresholds might be less than a GDP per capita in low and medium HDI countries and between one and two GDP per capita in high and very high HDI countries.

scholarly journals A High-Accuracy and Power-Efficient Self-Optimizing Wireless Water Level Monitoring IoT Device for Smart City

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 1936
Author(s):  
Tsun-Kuang Chi ◽  
Hsiao-Chi Chen ◽  
Shih-Lun Chen ◽  
Patricia Angela R. Abu
Keyword(s):  
Power Consumption ◽  
Water Level ◽  
Smart City ◽  
High Accuracy ◽  
Control Device ◽  
Power Efficient ◽  
Sensor Module ◽  
Monitoring Applications ◽  
Level Monitoring ◽  
Water Level Monitoring

In this paper, a novel self-optimizing water level monitoring methodology is proposed for smart city applications. Considering system maintenance, the efficiency of power consumption and accuracy will be important for Internet of Things (IoT) devices and systems. A multi-step measurement mechanism and power self-charging process are proposed in this study for improving the efficiency of a device for water level monitoring applications. The proposed methodology improved accuracy by 0.16–0.39% by moving the sensor to estimate the distance relative to different locations. Additional power is generated by executing a multi-step measurement while the power self-optimizing process used dynamically adjusts the settings to balance the current of charging and discharging. The battery level can efficiently go over 50% in a stable charging simulation. These methodologies were successfully implemented using an embedded control device, an ultrasonic sensor module, a LORA transmission module, and a stepper motor. According to the experimental results, the proposed multi-step methodology has the benefits of high accuracy and efficient power consumption for water level monitoring applications.

scholarly journals The Application of Electromagnetic Sensors for Determination of Cherenkov Cone Inside and in the Vicinity of the Detector Volume in Any Environment Known

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 992
Author(s):  
Valeriu Savu ◽  
Mădălin Ion Rusu ◽  
Dan Savastru
Keyword(s):  
Energy Levels ◽  
Cherenkov Detector ◽  
Electromagnetic Sensors ◽  
The Cost ◽  
Information Errors ◽  
The Universe ◽  
Large Frequency ◽  
Very High ◽  
Detector Volume

The neutrinos of cosmic radiation, due to interaction with any known medium in which the Cherenkov detector is used, produce energy radiation phenomena in the form of a Cherenkov cone, in very large frequency spectrum. These neutrinos carry with them the information about the phenomena that produced them and by detecting the electromagnetic energies generated by the Cherenkov cone, we can find information about the phenomena that formed in the universe, at a much greater distance, than possibility of actually detection with current technologies. At present, a very high number of sensors for detection electromagnetic energy is required. Thus, some sensors may detect very low energy levels, which can lead to the erroneous determination of the Cherenkov cone, thus leading to information errors. As a novelty, we propose, to use these sensors for determination of the dielectrically permittivity of any known medium in which the Cherenkov detector is used, by preliminary measurements, the subsequent simulation of the data and the reconstruction of the Cherenkov cone, leading to a significant reduction of problems and minimizing the number of sensors, implicitly the cost reductions. At the same time, we offer the possibility of reconstructing the Cherenkov cone outside the detector volume.

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