1,721,692 research outputs found
Dataset of EVE: Explainable Vector Based Embedding Technique Using Wikipedia
No full textDataset used in research contribution EVE: Explainable Vector Based Embedding Technique Using Wikipedia </i
Dataset of EVE: Explainable Vector Based Embedding Technique Using Wikipedia
No full textDataset used in research contribution EVE: Explainable Vector Based Embedding Technique Using Wikipedia </i
A Novel Adaptive Algorithm for the Modeling and Regulation of Power Converters for Grid Applications
Full text linkL'abstract è presente nell'allegato / the abstract is in the attachmen
Sensorless position control of solenoid actuators for soft landing using super-twisting sliding mode control
No full text This article presents an open-loop control methodology to achieve lower seating velocities (i.e. soft-landing) for solenoid-based injector systems which are widely used in automotive as fuel injection valves or gas exchange valves of internal combustion engines to spray various fluids. Physical sensors are not preferred to be used in injectors in order to increase reliability and reduce cost. As a result, it becomes impossible to control the motion of the moving parts within injectors in closed-loop. This study offers a novel sensorless position tracking approach with which impact noise can be reduced and mechanical wear and tear can be minimized. Using the Hammerstein-Wiener modeling method and a super-twisting sliding mode controller this new approach replicates the dynamics of the injector and tracks specially designed position reference signals to achieve soft landing. The effectiveness of this approach is based on the observed negligible position and velocity errors between the estimated and actual measurements. This study also offers a new way to optimize the settling time of the injector systems, while ensuring soft landing. Using the proposed approach here, the closing profiles of the reference signals were refined according to the admittance time of the solenoid actuator and the optimal closing profile signals were selected based on performance comparisons with the baseline. The results of the experiments are presented and the promising effectiveness of the proposed approach is discussed. </jats:p
Sliding mode control of an electromechanical solenoid actuator for soft landing
No full textElectromechanical solenoid actuators are widely used in industrial applications that require fast and linear motion. High velocities can be achieved in small stroke lengths; in turn the motion results with high-velocity impacts, which may cause excessive noise and create mechanical damage to the parts. In this paper, three distinct position reference profiles are tested using Proportional Integral Derivative (PID) control and Sliding Mode Control (SMC) in a closed loop to achieve the soft landing of the actuators plunger. The experimental results reveal that the SMC is robust and can be used to reduce the impact of the fast motion.TÜBİTA
Mass flow rate control of solenoid-based injectors
No full textThis paper presents a mass flow rate control method for solenoid-based injectors in open-loop, i.e. without physical
sensor feedback. Measuring the mass flow rate in injectors is important because the performance of the injector
determines fuel consumption and emissions. While it is possible to perform this control using different types of sensors,
this would increase the cost and reduce the reliability. With this study, it was aimed to control the mass flow rate
of solenoid-based injectors using continuous switching control to regulate the injector’s needle displacement without
using sensors. For this purpose, a solenoid-actuated injector prototype was created. Model-based estimators were
used to determine the states of the injector, while a super-twisting sliding mode controller was used to track the desired
mass flow rate references. The results of the experiments showed that tracking for sinusoidal, triangular, and square
trajectories yielded a mass flow rate percent error of less than 1.06. The proposed open-loop control algorithm can be
used to track different mass flow rate references in internal combustion engines.Post prin
Phase Equilibria of Bio-Oil Compounds
No full textThermodynamic information related to bio-oil is very important for the design and development of biorefining and upgrading processes. In this study, the thermodynamic properties of selected bio-oil compounds and their mixtures were measured and modelled at various temperatures and pressures. These data were acquired using various type of phase equilibrium apparatus, mostly designed and developed in house.
In particular, limiting activity coefficients of bio-oil compounds in water, solubility of CO and H2 in bio-oil compounds, mutual solubility of bio-oil compounds and water and excess properties of aqueous solutions of bio-oil compounds at infinite dilution were measured. Rapid Inert gas stripping equipment was designed by Prof. Dominique Richon. Butanol-water mixture was used as a reference system for equipment validation. The equipment was further used for the determination of limiting activity coefficients of bio-oil compounds in water. Limiting activity coefficients of five bio-oil compounds in water were also measured using classical inert gas stripping technique (glass apparatus) at UCT Prague during a research visit. The solubility of CO in bio-oil compounds at different temperatures and pressures was measured using static-analytic VLE technique employing ROLSI™ samplers while the solubility of hydrogen in bio-oil compounds was measured using a continuous flow apparatus at different temperatures and pressures. The partial molar excess thermodynamic properties at infinite dilution were measured using a tandem calo-densimetry technique employing a calorimeter and a vibrating tube densimeter in tandem arrangement. VLLE measurements of bio-oil compounds and water at different conditions were carried out in a high pressure and high temperature static analytic VLLE apparatus, equipped with novel high temperature Pneumatic capillary sampler, designed and developed by Prof. Dominique Richon and D.Sc. (Tech.) Petri Uusi-Kyyny.
Both classical (cubic EoS and local composition liquid activity coefficient) and modern (PC-SAFT EoS) thermodynamic modelling approaches were used in this work. The solubility of CO in bio-oil compounds was modelled with SRK, PR and PC-SAFT EoS. A comparison of these models was made. Hydrogen solubility in bio-oil compounds was modelled with Peng Robinson EoS. The mutual solubilities of bio-oil compounds and water at high temperatures and pressures were modelled using UNIQUAC and NRTL liquid activity coefficient models. Furthermore, Hayden O' Connell and Tsonopoulos correlations were used for the vapor phase corrections in the determination of limiting activity coefficients
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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