Search results for "Speed"
showing 10 items of 876 documents
Impact of wind speed on ventilation performance within a container installed with photovoltaic inverter
2017
Abstract PV inverter needs proper ventilation for reducing the heat dissipation of the electronic components. In this work, a container installed with PV inverter is considered with different configurations of cooling channels within the container for ventilation analysis. Typically, high capacity PV inverters are installed inside the container and therefore inverters, are not experiencing external wind effects and it depends on the configuration of cooling channels. In this work, the main cooling channel is located at the top of the inverter; inlet and outlet ventilation holes are located on the side of cross ventilation. They help in analyzing the cooling design, dependent on site specifi…
Analysis of the maximization of wind turbine energy yield using a continuously variable transmission system
2017
Abstract In this paper, an analytic study of the subject of mechanical power transmission in HAWT wind turbine has been carried out. For the most part, the study analyzes the use of continuously variable transmission (CVT) in order to allow the turbine and the electric generator to couple, allowing in turn, an unremitting transmission ratio adjustment. In low-wind sites, the design criteria suggest an oversizing of the wind turbine in order to generate adequate electrical power even at low wind speed. The proposed solution enhances the space of operating points since it allows the electric generator to release the rotational speed from the turbine one (limited due to structural integrity). …
On the assessment of power consumption and critical impeller speed in vortexing unbaffled stirred tanks
2017
Abstract Unbaffled stirred tanks are increasingly recognized as a viable alternative to common baffled tanks for a number of processes and bio-processes where the presence of baffles is undesirable. Notwithstanding the increasing industrial interest towards unbaffled tanks, available experimental information on their behaviour is still very poor, even for important parameters such as mechanical power drawn and critical impeller speed (Ncr) at which the transition between non-aerated (sub-critical regime) and aerated (super-critical regime) conditions occurs. In this work the influence of Reynolds and Froude numbers on power consumption characteristics of unbaffled stirred tanks is presented…
Hybrid Procedure for Automated Detection of Cracking with 3D Pavement Data
2016
Pavement cracks are considered a major indicator of pavement performance. Because traditional manual crack surveys are dangerous, time consuming, and expensive, technologies have been developed to collect high-speed pavement images, and numerous algorithms have been proposed to detect cracks on pavement surface. The latest PaveVision3D Ultra system (3D Ultra) has been implemented to achieve 30-kHz three-dimensional (3D) scanning rate for 1-mm resolution pavement surface data at highway speed up to 100 km/h (60 mi/h). This paper presents the application of a hybrid procedure for automated crack detection on 3D pavement data collected using 3D Ultra. The procedure combines three different me…
A Bayesian Network Model for Fire Assessment and Prediction
2015
Smartphones and other wearable computers with modern sensor technologies are becoming more advanced and widespread. This paper proposes exploiting those devices to help the firefighting operation. It introduces a Bayesian network model that infers the state of the fire and predicts its future development based on smartphone sensor data gathered within the fire area. The model provides a prediction accuracy of 84.79i¾?% and an area under the curve of 0.83. This solution had also been tested in the context of a fire drill and proved to help firefighters assess the fire situation and speed up their work.
Interior permanent magnet synchronous motors: Impact of the variability of the parameters on their efficiency
2016
In the scientific literature, various authors presented different control strategies aimed to increase the efficiency of the interior permanent magnet synchronous motors. These strategies, starting from a well-known mathematical model of the dynamic behaviour of the motor, are able to reduce the power losses acting on the magnetizing component of the stator current. However, none of the proposed approaches takes into account that, varying the working conditions of the motor, also the values of the parameters, which have an impact on the power losses, can vary. In this paper, therefore, starting from an accurate measurement of the motor characteristics for various values of speed and load, w…
Visual scale factor for speed perception
2011
Speed perception is an important task depending mainly on optic flow that the driver must perform continuously to control his/her vehicle. Unfortunately, it appears that in some driving simulators speed perception is under estimated, leading into speed production higher than in real conditions. Perceptual validity is then not good enough to study driver’s behavior. To solve this problem, a technique has recently seen the light, which consists of modifying the geometric field of view (GFOV) while keeping the real field of view (FOV) constant. We define our visual scale factor as the ratio between the GFOV and the FOV. The present study has been carried out on the SAAM dynamic driving simulat…
Experimental study on efficiency enhancement in Interior Permanent Magnet Synchronous machines
2015
This paper presents an experimental study on the efficiency variation occurring in an IPMSM (Interior Permanent Magnet Synchronous Motor) with respect to the direct axis current component and for several working conditions. Such investigation is the starting point for the arrangement of a speed control drive system equipped with a real-time power losses minimization algorithm. More in detail, a test bench is set up to carry out the measurements needed for the final power loss identification. The experimental investigation is developed by performing tests at different speed, magnetization and load conditions. From the obtained results, it can be stated that the IPMSM efficiency can be maximi…
Experimental characterization of a wind generator prototype for sustainable small wind farms
2016
This paper presents the experimental characterization of a wind turbine prototype used for micro wind farms. The proposed prototype, whose advantages can be summarized in versatility of application, low noise and compactness, can generate 1 kW of rated power for a wind speed equal to 4 m/s. The tests here reported and carried out by means of an experimental test bench confirm that the prototype is well designed and adequate for the purpose of its application.
Speed Stochastic Processes and Freeway Reliability Estimation: Evidence from the A22 Freeway, Italy
2013
In this paper, a criterion for predicting the reliability of freeway traffic flow is presented. The idea is based on an analysis of spot speed time series divided into sequences of events of random and homogeneous traffic processes. For each process, the flow rate and density were calculated; then the relationships between parameters of spot speed processes and vehicular density were obtained. Using these relationships and a simulation procedure for the spot speed process, a formulation for predicting the reliability of traffic flow moving along the offside lane on the freeway roadway was derived. Through this formulation and the measurements of flow rate and speed, the probability of insta…