Search results for "Arti"
showing 10 items of 43777 documents
Design and experimental validation of a magnetic device for stem cell culture.
2020
Cell culture of bone and tendon tissues requires mechanical stimulation of the cells in order to mimic their physiological state. In the present work, a device has been conceived and developed to generate a controlled magnetic field with a homogeneous gradient in the working space. The design requirement was to maximize the magnetic flux gradient, assuring a minimum magnetizing value in a 15 mm × 15 mm working area, which highly increases the normal operating range of this sort of devices. The objective is to use the machine for two types of biological tests: magnetic irradiation of biological samples and force generation on paramagnetic particles embedded in scaffolds for cell culture. The…
Sensorless control of induction motors using an extended Kalman filter and linear quadratic tracking
2017
Induction motors are the most commonly used prime-movers in industrial applications. Many induction motors supplied by frequency converters are coupled with a physical angular rotor position/velocity sensor which makes the drive complex and require maintenance. This paper presents a sensorless control structure to avoid using a physical angular rotor position/velocity sensor. The proposed method estimates and control the angular rotor velocity using optimal control theory. The optimal controller used in this paper is based on linear quadratic tracking and the states of the machine are estimated using an extended Kalman filter. Both the controller and the estimator utilize the same internal …
Polarization and acoustic properties of barium-modified lead-free potassium–sodium niobate ceramics
2017
The publication costs of this article were covered by the Estonian Academy of Sciences and the University of Tartu.
Field effect in the viscosity of magnetic colloids studied by multi-particle collision dynamics
2019
Abstract Colloidal solutions of magnetic nanoparticles are usually employed when the fluidity and magnetic properties are required at the same time, either in technical or biomedical applications. However, when the magnetic size of the nanoparticles is large enough (>12–15 nm) the colloid may form an equilibrium structure with or without the external magnetic field, which can significantly influence its rheology. Using multi-particle collision dynamics we study the internal structure and viscosity of the magnetic colloids at varying magnitudes of the externally applied field. We show a generalized structural behavior across all studied regimes and an appreciable increase of flow resistance …
PD characteristics at Square Shaped Voltages Applying Two Different Detecting Techniques
2016
Nowadays power electronic converters are widely used and the fast switching voltage fronts results in an increased stress on the insulation material and may cause a reduction of the HV systems reliability. Nonsinusoidal voltage waveform have influence on the partial discharges (PD) characteristics in insulating systems due to the increased harmonic content which causes problems mainly in electrical PD measurement setups. In fact, impulse voltages cause strong switching disturbances, which make it much more difficult to distinguish PD signals from noise. This work investigates the influence of repetitive steep pulses on different types of test objects exposed to square wave voltages applying…
Partial discharges at different voltage waveshapes: Comparison between two different acquisition systems
2018
In modern HV apparatuses the wide use of electronic converters, increase the stress on the involved insulation systems and thus affect the reliability of the whole power grid. Additionally, such non-sinusoidal voltage shapes contain high gradient flanks that create problems in the detection of partial discharge (PD) activity. The aim of this paper is to discuss the methodology on how to suitably approach PD detection in insulation systems exposed to various voltage waveshapes in general by comparing two different measuring systems. The first one, equipped with a resonant PD decoupler, designed specifically for detection at typical power electronic waveshapes and the other one, based on an a…
Multi-application Based Fault-Tolerant Network-on-Chip Design for Mesh Topology Using Reconfigurable Architecture
2019
In this paper, we propose a two-step fault-tolerant approach to address the faults occurred in cores. In the first stage, a Particle Swarm Optimization (PSO) based approach has been proposed for the fault-tolerant mapping of multiple applications on to the mesh based reconfigurable architecture by introducing spare cores and a heuristic has been proposed for the reconfiguration in the second stage. The proposed approach has been experimented by taking several benchmark applications into consideration. Communication cost comparisons have been carried out by taking the failed cores as user input and the experimental results show that our approach could get improvements in terms of communicati…
Computational volumetric reconstruction of integral imaging with improved depth resolution considering continuously non-uniform shifting pixels
2018
Abstract In this paper, we propose a new computational volumetric reconstruction technique of three-dimensional (3D) integral imaging for depth resolution enhancement by using non-uniform and integer-valued shifting pixels. In a typical integral imaging system, 3D images can be recorded and visualized using a lenslet array. In previous studies, many computational reconstruction techniques such as computational volumetric reconstruction and pixel of elemental images rearrangement technique (PERT) have been reported. However, a computational volumetric reconstruction technique has low visual quality and depth resolution because low-resolution elemental images and uniformly distributed shiftin…
Integral-Imaging display from stereo-Kinect capture
2017
In this paper, we propose a new approach in order to improve the quality of microimages and display them onto an integral imaging monitor. Our main proposal is based on the stereo-hybrid 3D camera system. Originally, hybrid camera system has dissimilarity itself. We interpret our method in order to equalize the hybrid sensor's characteristics and 3D data modification strategy. We generate integral image by using synthetic back-projection mapping method. Finally, we project the integral image onto our proposed display system. We illustrate this procedure with some imaging experiments in order to prove an advantage of our approach.
Ionization efficiency studies with charge breeder and conventional electron cyclotron resonance ion source
2013
Radioactive Ion Beams play an increasingly important role in several European research facility programs such as SPES, SPIRAL1 Upgrade, and SPIRAL2, but even more for those such as EURISOL. Although remarkable advances of ECRIS charge breeders (CBs) have been achieved, further studies are needed to gain insight on the physics of the charge breeding process. The fundamental plasma processes of charge breeders are studied in the frame of the European collaboration project, EMILIE, for optimizing the charge breeding. Important information on the charge breeding can be obtained by conducting similar experiments using the gas mixing and 2-frequency heating techniques with a conventional JYFL 14 …