Search results for "Bust"
showing 10 items of 1000 documents
Determinación experimental del equilibrio entre fases de sistemas azeotrópicos relacionados con biocombustibles. Selección de entrainers de bajo impa…
2016
El problema del calentamiento global hace indispensable plantear alternativas que permitan llevar a cabo una transición desde el actual sistema energético basado en combustibles fósiles hacia otro en el que tengan mayor presencia las llamas energías “limpias” o renovables. De entre todas ellas, el uso de biocombustibles es una de las opciones más atractivas y con un estado de desarrollo más avanzado. Sin embargo, aún existen una serie de problemas tecnológicos, como por ejemplo la deshidratación de los biocombustibles basados en el bioetanol y biopropanol, pues al tratarse de mezclas azeotrópicas el agua que contienen no puede eliminarse mediante destilación convencional. En este sentido, e…
Movement Detection with Event-Based Cameras: Comparison with Frame-Based Cameras in Robot Object Tracking Using Powerlink Communication
2018
Event-based cameras are not common in industrial applications despite the fact that they can add multiple advantages for applications with moving objects. In comparison with frame-based cameras, the amount of generated data is very low while keeping the main information in the scene. For an industrial environment with interconnected systems, data reduction becomes very important to avoid network congestion and provide faster response time. However, the use of new sensors as event-based cameras is not common since they do not usually provide connectivity to industrial buses. This work develops a network node based on a Field Programmable Gate Array (FPGA), including data acquisition and trac…
Optimization of Delayed-State Kalman-Filter-based Algorithm via Differential Evolution for Sensorless Control of Induction Motors
2010
This paper proposes the employment of the differential evolution (DE) to offline optimize the covariance matrices of a new reduced delayed-state Kalman-filter (DSKF)-based algorithm which estimates the stator-flux linkage components, in the stationary reference frame, to realize sensorless control of induction motors (IMs). The DSKF-based algorithm uses the derivatives of the stator-flux components as mathematical model and the stator-voltage equations as observation model so that only a vector of four variables has to be offline optimized. Numerical results, carried out using a low-speed training test, show that the proposed DE-based approach is very promising and clearly outperforms a cla…
Physical properties of aerosol particles measured from a bubbling fluidized bed boiler
2015
Abstract Increased use of biomass and waste fuels, and the consequent corrosion problem have led to an increased need to study and monitor the combustion processes. This study presents an extensive physical characterization of aerosol particles measured from a bubbling fluidized bed boiler with different fuel mixtures and optional ferric sulfate feeding. The fuel mixtures included bark, sludge, peat and solid recovered fuel. Previously, the characterization of the particles analyzed from a fluidized bed reactor has mainly focused on chemical off-line analysis of collected impactor samples, large coarse mode particles or laboratory-scale reactors. In this study, the focus is in the particle …
Fragmentation du combustible nucléaire UO2 en environnement oxydant : Etude cinétique et phénoménologique
2006
Une des voies envisagées pour apporter de la flexibilité à la gestion du combustible UO2 usé/irradié est son entreposage à sec. Ce mode de gestion pose en particulier la question de la tenue du combustible en cas de scénario accidentel qui entraînerait la mise à l'air des pastilles de UO2. La cinétique d'oxydation et la phénoménologie de la fragmentation de UO2 entre 250 et 330°C ont été étudiées à partir de vieillissements sous O2 et sous air de monocristaux et de fragments de pastilles de combustible non irradiés. En environnement oxydant, l'initiation de la fissuration semble due à la relaxation des contraintes de traction induites par la contraction du réseau cristallin lors de la crois…
Discovering Gender-Specific Knowledge from Finnish Basic Education using PISA Scale Indices
2014
The Programme for International Student Assessment, PISA, is a worldwide study to assess knowledge and skills of 15- year-old students. Results of the latest PISA survey conducted in 2012 were published in December 2013. According to the results, Finland is one of the few countries where girls performed better in mathematics than boys. The purpose of this work is to refine the analysis of this observation by using education data mining techniques. More precisely, as part of standard PISA preprocessing phase certain scale indices are constructed based on information gathered from the background questionnaire of each participating student. The indices describe, e.g., students’ engagement, dri…
Electric Field Impact On The Biomass Gasification And Combustion Dynamics
2015
Experimental investigations of the DC electric field effect on thermal decomposition of biomass, formation of the axial flow of volatiles (CO, H2, CxHy), mixing of volatiles with swirling airflow at low swirl intensity (S ≈ 0.2-0.35), their ignition and on formation of combustion dynamics are carried out with the aim to understand the mechanism of electric field influence on biomass gasification, combustion of volatiles and heat energy production. The DC electric field effect on combustion dynamics was studied by varying the positive bias voltage of the central electrode from 0.6 kV to 3 kV, whereas the ion current was limited to 2 mA. The results of experimental investigations confirm the …
Preliminary Experimental Study on Double Fuel HCCI Combustion
2015
AbstractThis paper regards an experimental study on a particular internal combustion engine process which combines Double Fuel combustion with Homogeneous Charge Compression Ignition (HCCI) using mixtures of natural gas (NG) and gasoline. The tests performed on a CFR engine demonstrate that HCCI combustion can be achieved using NG-gasoline mixtures without knocking occurrence for low to medium engine load varying the proportion between the two fuels. The main advantage of this new combustion process relies on the noticeable higher engine efficiency obtained with respect to conventional spark ignition operation, and on the strong reduction of NOX emissions.
Booms and busts in housing markets: determinants and implications
2009
This study looks at real estate price booms and busts in industrialised countries. It identifies major and persistent deviations from long term trends for 18 countries and estimates the probabilities of their occurrence using a Random Effects Panel Probit model over the period 1980-2007. It finds that 1) most recent housing booms have been very persistent and of a significant magnitude; 2) there appears to be a strong correlation between the persistence and magnitude of booms and subsequent busts; 3) economic costs (in terms of GDP losses during the post-boom phase) depend significantly on the magnitude and duration of the boom and money and credit developments during that period; 4) a numb…
Moving RTS/CTS to the frequency domain: an efficient contention scheme for 802.11ax networks
2019
In this paper, we propose a contention mechanism based on the execution of multiple contention rounds in the frequency domain (ReCHo), which is designed to offer high throughput performance and robustness with respect to imperfect carrier sensing. The main idea is using narrow tones as signalling messages for performing channel access contentions and allowing the Access Point (AP) to echo these signals, in order to extend the sensing capabilities to all the stations associated to the AP. In particular, we refer to the emerging IEEE 802.11ax standard, showing how our scheme can boost performance of random access with respect to the current version of IEEE 802.11ax OFDMA Back-Off (OBO), even …