Letteratura scientifica selezionata sul tema "Non linear device"
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Articoli di riviste sul tema "Non linear device"
1
Richards, Jeffrey. "Non-linear vibration device". Journal of the Acoustical Society of America 102, n. 6 (1997): 3247. http://dx.doi.org/10.1121/1.420159.
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Sheng, Cao P. "Non‐linear electromagnetic vibration device". Journal of the Acoustical Society of America 85, n. 4 (aprile 1989): 1808. http://dx.doi.org/10.1121/1.397903.
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3
Negre, Christian F. A., Pablo A. Gallay e Cristián G. Sánchez. "Model non-linear nano-electronic device". Chemical Physics Letters 460, n. 1-3 (luglio 2008): 220–24. http://dx.doi.org/10.1016/j.cplett.2008.06.006.
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Kalibjian, Ralph. "Non-linear optical crystal vibration sensing device". Journal of the Acoustical Society of America 99, n. 3 (1996): 1279. http://dx.doi.org/10.1121/1.414752.
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5
Babaei, Mohammadreza, Lütfiye Durak-Ata e Ümit Aygölü. "Performance Analysis of Dual-Hop AF Relaying with Non-Linear/Linear Energy Harvesting". Sensors 22, n. 16 (10 agosto 2022): 5987. http://dx.doi.org/10.3390/s22165987.
Testo completoAbstract (sommario):
Massive device-to-device communication nodes and Internet of Things (IoT) devices are expected to be crucial components in next-generation wireless networks. However, the energy constraint of these nodes presents a challenge since the energy of the batteries is limited. Motivated by this, radio frequency energy harvesting (EH) has been developed as an efficient strategy to overcome the energy constraint of IoT devices and sensor networks. In this paper, a wireless-powered dual-hop amplify-and-forward relaying system, in the absence of a direct link between the source (S) and the destination (D), is considered. It is assumed that a dedicated power beacon (PB) transmits an energy-bearing signal from which the power-constrained S and relay (R) harvest energy. Theoretical derivations of bit error probability, outage probability, and throughput expressions are performed for both linear and non-linear energy harvesting models. Moreover, the theoretical results provided for different system parameters are validated via Monte Carlo simulations. The obtained results reveal the difference between the realistic non-linear EH model and the conventional linear EH model, which overestimates the system performance at high levels of harvested energy. Thus, it leads to misunderstanding the real performance of the EH systems. However, at low levels of harvested energy, both models behave similarly and provide realistic results.
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Low, P. S., R. Ramlan, H. A. Ghani e N. S. Muhammad. "Experimental Analysis on the Transduction Coefficient of a Non-Linear Electromagnetic Energy Harvesting Device with Softening Stiffness". International Journal of Automotive and Mechanical Engineering 17, n. 2 (3 luglio 2020): 7816–31. http://dx.doi.org/10.15282/ijame.17.2.2020.01.0582.
Testo completoAbstract (sommario):
Nonlinear energy harvesting devices in the form of stiffness nonlinearity have emerged as among the effective solutions to overcome the performance limit of linear energy harvesting devices. However, up to now, researches on the nonlinear devices are only focusing on the ability to widen the bandwidth while the limit of employing linear transduction coefficient in a nonlinear system has yet to be heavily discussed. This paper investigates on the transduction coefficient for both linear and nonlinear systems of an electromagnetic energy harvesting device as a function of the excitation frequency. It is proven that the transduction coefficient of the nonlinear device is larger than its equivalent linear device, especially in the multi-stable solutions region. In common practice, the nonlinearity in the nonlinear system is considered weak, and its transduction coefficient is assumed to converge to the one produced by the linear system. The limits to which the transduction coefficient of a linear system can be employed on the nonlinear system were drawn based on the experimental analysis conducted on the proposed device. The device was designed to perform as a linear or nonlinear system, where the degree of nonlinearity was changed by varying the gap between the magnets. The limit of the transduction coefficient was determined from the analysis of the harmonic ratio. The results show that the linear transduction coefficient is valid to be employed to the nonlinear system when the harmonic ratio is less than five per cent at the multi-stable solutions region.
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Liu, Dan Dan, e Chun Rui Tang. "The Variable Non-Linear Flow Channel Method and Device". Advanced Materials Research 136 (ottobre 2010): 158–61. http://dx.doi.org/10.4028/www.scientific.net/amr.136.158.
Testo completoAbstract (sommario):
In order to overcome shortcomings of traditional hydraulic control valve, the variable non-linear flow channel method and device is proposed, which can make magneto-rheological fluid channel in the magnetic gap space variable non-linear. In the magnetic gap space setting separated magnetic pressure tablets make magneto-rheological fluid non-line fluid along the separated magnetic pressure tablets, so the magneto-rheological fluid channel length is lengthen and it can increase the utilization of a limited magnetic line. Under the condition of magnetic gap size fixedness, improving pressure difference size of controllable fluid of magnetic fluids can achieve goals of energy conservation and reducing the size of magneto-rheological valves.
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Jabbar, Hamid, e Taikyeong Jeong. "Ambient Light Energy Harvesting and Numerical Modeling of Non-Linear Phenomena". Applied Sciences 12, n. 4 (16 febbraio 2022): 2068. http://dx.doi.org/10.3390/app12042068.
Testo completoAbstract (sommario):
Ambient light is an energy-harvesting source that can recharge a battery with less human interaction and can be used to prolong the operational time of the Internet of Things, e.g., mobile phones and wearable devices. Available light energy is insufficient for directly charging mobile phones and wearable devices, but it can supplement batteries to power some low-energy-consuming critical functions of the wearable device, especially in low-power consumption wearables. However, in an emergency scenario when the battery’s operational time is not sufficient or a battery charging source is unavailable, a solution is required to extend the limited battery span for mobile and wearable devices. This work presents the bottlenecks and new advancements in the commercialization of photovoltaics for smartphones and wearable technologies based on ambient light energy harvesting. A new technique, in which a smartphone cover is used as a solar concentrator to enhance light energy harvesting associated with algorithms, is experimentally demonstrated. Our research outcomes show that solar concentrators can improve light intensity by approximately 1.85 and 1.43 times at 90° and 71° angles, respectively, thus harvesting more ambient light energy at 2500 lx light intensity in a typical office environment. Type-1 PV and Type-2 PV cells were able to charge the additional battery in 8 h under 2500 lx lighting intensity in an indoor office environment. A system and logic algorithm technique is presented to efficiently transfer harvested light energy to perform low-energy consumption operations in a device, in order to improve the operational time of the device’s battery.
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Nazarov, Maxim A., e Edward V. Semyonov. "Simple behavioral model of a recording device using a second-order non-linear recursive filter". Proceedings of Tomsk State University of Control Systems and Radioelectronics 25, n. 4 (2022): 110–14. http://dx.doi.org/10.21293/1818-0442-2022-25-4-110-114.
Testo completoAbstract (sommario):
A method to analyze the non-linear-inertial properties of devices for recording (analog-to-digital conversion) of signals is considered. The method includes a building of a model of a digitizing device in the form of a nonlinear recursive filter of a limited order (second or third). Two or four non-linear functions in such a model are proposed to be considered as characteristics of the non- linearity of the device. The influence of these characteristics on different parts of the transient response of the device is indicated. For the selected example (digital oscilloscope), it is shown that the nonlinearity of the oscilloscope quantizing unit itself has an unsystematic character, but is small against the background of relatively smooth distortions in the analog path of the oscilloscope.
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Zhai, Xiangping, Xiaoxiao Guan, Jiabin Yuan, Hu Liu e Joel J. P. C. Rodrigues. "Energy-Efficiency Maximization with Non-linear Fractional Programming for Intelligent Device-to-Device Communications". Mobile Networks and Applications 23, n. 2 (16 ottobre 2017): 308–17. http://dx.doi.org/10.1007/s11036-017-0951-5.
Testo completoTesi sul tema "Non linear device"
1
Ghani, M. M. Abdul. "Protection of cross-bonded cable systems using non-linear inductive device". Thesis, University of Southampton, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303097.
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Ramlan, Roszaidi. "Effects of non-linear stiffness on performance of an energy harvesting device". Thesis, University of Southampton, 2009. https://eprints.soton.ac.uk/69588/.
Testo completoAbstract (sommario):
Vibration-based energy harvesting devices have received much attention over the past few years due to the need to power wireless devices in remote or hostile environments. To date, resonant linear generators have been the most common type of generators used in harvesting energy for such devices. Simple tuning and modelling methods make it a more favourable solution theoretically if not practically. This thesis considers the limitations of resonant linear devices and investigates two non-linear generators to see if they can outperform the linear devices in certain situations. So far, in most of the literature, the energy harvester is assumed to be very small dynamically compared to the source so the source is not aected by the presence of the device. This thesis considers how the dynamics of the source is aected by the device if its impedance is signicant compared to the source. A tuning condition for maximum power transfer from the source to the device is derived. This tuning condition converges to the one presented in most of the literature when the impedance of the device is assumed to be very small compared to that of the source i.e. tuned so that the natural frequency of the device equals the excitation frequency. For the case when the impedance of the device has a negligible eect on the source, the performance of the device is only limited to a narrow frequency band and drops o rapidly if mistuned. To accommodate the mistuning limitations, new types of generators are proposed mainly by using a non-linear mechanism. These mechanisms are made up of a non-linear spring connected together with a mass and a linear viscous damper i.e. the energy harvesting component. The analysis of the fundamental performance limit of any non-linear device compared to that of a tuned linear device is carried out using the principal of conservation of energy. The analysis reveals that the performance of a non-linear device in terms of the power harvested is at most 4= greater than that of a tuned linear system and is strongly dependent upon the type of the non-linearity used. Two types of non-linear mechanisms are studied in this thesis. The rst one is a non-linear bi-stable mechanism termed a snap-through mechanism which rapidly moves the mass between two stable states. The aim is to steepen the displacement response curve as a function of time which results in the increase of velocity for a given excitation, thus increasing the amount of power harvested. This study reveals that the performance of the mechanism is better than a linear system when the natural frequency of the system is much higher than the excitation frequency. The study also shows that the power harvested by this mechanism rolls o at a slower rate compared to that of the linear system. Another non-linear mechanism described in this thesis uses a hardening-type spring. The aim of this mechanism is to provide a wider bandwidth over which the power can be harvested. This thesis presents numerical solutions and approximate analytical solutions for the bandwidth and eective viscous damping of a non-linear device employing a hardening-type stiness. Unlike the linear system, in which the bandwidth is only dependent on the damping ratio, it is found that the bandwidth of the nonlinear device depends on both the strength of the nonlinearity and the damping ratio. Experimental results are presented to validate the theoretical results. This thesis also investigates the benets of the non-linear device for a low frequency and high amplitude application using the measured vibration inputs from human motion such as walking and running. The eect of harmonics on the power harvested is also studied. Numerical simulations are carried out using measured input vibrations from human motion to study the best placement of the natural frequency of the device across the range of harmonics.
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Murrell, Jonathan Kenneth Jeffrey. "Non-linear behaviour of a Superconducting Quantum Interference Device coupled to a radio frequency oscillator". Thesis, University of Sussex, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366212.
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Arenas, Joshua A. "Evaluation of a Novel Myoelectric Training Device". VCU Scholars Compass, 2015. http://scholarscompass.vcu.edu/etd/4050.
Testo completoAbstract (sommario):
Recent technological developments have implemented the use of proportional control in prosthetic hands, giving rise to the importance of appropriate myoelectric control. EMG models in the past have assumed a linear proportionality to simplify the EMG-force relationships. However, it has been shown that a non-linear EMG-force relationship may be a more effective model. This study focused on evaluating three different control algorithms for a novel myoelectric training device, consisting of a toy car controlled by EMG signals from the distal muscles in the arm. Sixteen healthy adult subjects (5 male and 11 female) with an average age of 23.6 years (SD = 2.7) were asked to drive the car through a slalom course. Completion times as well as number of errors (wall hits, cone hits, and reversals) were recorded to evaluate performance. The NASA TLX was administered to evaluate psychometrics such as mental demand, physical demand, frustration, and overall workload. The average total errors per trial on the final day of testing using the linear proportional algorithm was found to be statistically significantly (p < 0.05) lower than digital and non-linear proportional. The average course completion time per trial and overall workload using the non-linear proportional algorithm was found to be statistically significantly (p < 0.05) lower than digital and linear proportional. These results suggest that a non-linear algorithm would be most appropriate for myoelectric control in prosthetic hands.
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VADALA', Valeria. "CHARACTERIZATION AND MODELING OF LOW FREQUENCY DISPERSIVE EFFECTS IN III-V ELECTRON DEVICES". Doctoral thesis, Università degli studi di Ferrara, 2010. http://hdl.handle.net/11392/2389167.
Testo completoAbstract (sommario):
In this thesis, three years are enclosed of research activity in the topic of non linear
characterization and modelling of microwave devices. I investigated various issues
related to those topics which are closely related. In fact, to obtain good predictions,
empirical models require accurate measurements. This aspect is particularly
important when we want to predict the behavior of devices in nonlinear regime. More
and more applications take advantage of devices operation in non-linear regime. For
such a reason, non linear characterization is an hot topic and research activities have
focused particular attention on the need of characterize the nonlinear behaviour of
electron devices to obtain more accurate model prediction under actual operating
conditions.
The importance of this theme can be clearly understood by considering how, in
recent years, microwave technologies have become attractive for communication
applications and a number of commercial devices which are largely used in everyday
life (e.g., cell phone, GPS, wireless communication and so on).
In the first chapter the most important properties of devices and technologies used in
microwave electronics circuits will be dealt with. Particular attention is devoted to the
comparison between two III-V semiconductors for the fabrication of these devices:
GaAs, proven technology and used for years, and GaN, a youngest technology still
being tested. After this some of the most interesting issues related to III-V electron
devices, are discussed, such as low frequency dispersion. Finally a brief look will be
given at the non linear models for these devices.
In the second Chapter the most important microwave measurement systems
exploited to characterize the non linear dynamic behaviour of electron devices will be
discussed: pulsed setups, load / source-pull measurement systems, and Large
Signal time domain characterization systems. In particular, for each measurement
technique, it has been described the principle of operation and the application they
are used for.
In chapter III an alternative, technology-independent large-signal measurement setup,
developed during the PhD studies, is proposed for the experimental investigation
on the low frequency dispersion of current/voltage characteristics in micro- and
millimetre-wave electron devices and for their modeling. The proposed measurement
technique will be presented describing its hardware and software implementations
and showing different experimental examples.
In Chapter IV a new modeling approach will be presented accounting for the
nonlinear description of low-frequency dispersive effects (due to thermal phenomena
and traps) affecting electron devices. The model will be identified by exploiting
measurements carried out with the measurement system described in chapter III.
In the last Chapter a new, low-cost technique will be described for drawing “load-pull
contours” which are a powerful tool for power amplifier design. By exploiting the lowfrequency
measurement system described in chapter III and conventional
descriptions of device parasitic elements and nonlinear reactive effects, the proposed
approach allows to obtain the same information gathered by expensive highfrequency
load pull measurement systems.
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Afonja, Adetoso J. "Dynamics of Pitching Wave Energy Converter with Resonant U-Tank Power Extraction Device". Thesis, Virginia Tech, 2020. http://hdl.handle.net/10919/98782.
Testo completoAbstract (sommario):
This research revolves around the concept design and theoretical validation of a new type of wave energy converter (WEC), comprising a pitching floater integrated with a resonant U-tank (RUT) and a Wells turbine as power take-off (PTO). Theoretical formulation of a fully coupled multi-body dynamic system, incorporating the thermodynamic processes of the RUT air chamber, its interaction with the PTO dynamics and their coupling with the floater is presented.
Inaccuracies of the dynamic modeling of RUT based on Lloyd's low order model, which assumes constant hydrodynamic parameters irrespective of the frequency, are demonstrated by a series of high fidelity CFD simulations. These simulations are a systematic series of fully viscous turbulent simulations, using unsteady RANSE solvers, of the water sloshing at different frequencies of oscillation. Calibration of Lloyd’s model with CFD results evidenced that the RUT hydrodynamic parameters are not invariant to frequency.
A numerical model was developed based on Simulink WEC-Sim libraries to solve the non-linear thermo-hydrodynamic equations of the device in time domain. For power assessment, parametric investigations are conducted by varying the main dimensions of the RUT and power RAOs were computed for each iteration.
Performance in irregular sea state are assessed using a statistical approach with the assumption of linear wave theory. By superimposing spectrum energy density from two resource sites with RAO, mean annual energy production (MEAP) are computed. The predicted MEAP favorably compares with other existing devices, confirming the superior efficiency of the new proposed device over a larger range of incident wave frequency.M.S.
This study present results of an investigation into a new type of wave energy converter which can be deployed in ocean and by its pitch response motion, it can harvest wave energy and convert it to electrical energy. This device consist of a floater, a U-tank (resonant U-tank) with sloshing water free to oscillate in response to the floater motion and a pneumatic turbine which produces power as air is forced to travel across it. The pneumatic turbine is used as the power take-off (PTO) device. A medium fidelity approach was taken to carry out this study by applying Lloyd’s model which describes the motion of the sloshing water in a resonant U-tank. Computational fluid dynamics (CFD) studies were carried out to calibrate the hydrodynamic parameters of the resonant U-tank as described by Lloyd and it was discovered that these parameters are frequency dependent, therefore Lloyd’s model was modelled to be frequency dependent. The mathematical formulation coupling the thermodynamic evolution of air in the resonant U-tank chamber, modified Lloyd’s sloshing water equation, floater dynamics and PTO were presented for the integrated system. These set of thermo-hydrodynamic equations were solved with a numerical model developed using MATLAB/Simulink WEC-Sim Libraries in time domain in other to capture the non-linearity arising from the coupled dynamics. To assess the annual energy productivity of the device, wave statistical data from two resource sites, Western Hawaii and Eel River were selected and used to carrying out computations on different iterations of the device by varying the tank’s main dimensions. This results were promising with the most performing device iteration yielding mean annual energy production of 579 MWh for Western Hawaii.
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Kumar, Upkar. "Plasmon logic gates designed by modal engineering of 2-dimensional crystalline metal cavities". Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30170/document.
Testo completoAbstract (sommario):
L'objectif principal de cette thèse est de concevoir, fabriquer et caractériser les dispositifs plasmoniques basés sur les cavités métalliques bidimensionnelles monocristallines pour le transfert d'information et la réalisation d'opérations logiques. Les fonctionnalités ciblées émergent de l'ingénierie spatiale et spectrale de résonances plasmon d'ordre supérieur supportées par ces cavités prismatiques. Les nouveaux éléments étudiés dans cette thèse ouvrent la voie à de nouvelles stratégies de transfert et de traitement de l'information en optique intégrée et miniaturisée. Dans un premier temps, nous caractérisons la réponse optique des nanoplaquettes d'or ultra-fines et de taille submicronique (400 à 900 nm) par spectroscopie en champ sombre. La dispersion des résonances plasmoniques d'ordre supérieur de ces cavités est mesurée et comparée avec un bon accord aux simulations obtenues par la méthode des dyades de Green (GDM). En outre, nous présentons une analyse par décomposition lorentzienne des réponses spectrales de ces nanoprismes déposés sur des minces substrats métalliques. Nous avons, par ailleurs systématiquement étudié les effets qui pourraient modifier les résonances plasmoniques par microscopie de luminescence non-linéaire, qui s'est avérée un outil efficace pour observer la densité d'états locale des plasmons de surface (SPLDOS). En particulier, nous montrons que les caractéristiques spectrale et spatiale des résonances plasmoniques d'ordre supérieur peuvent être modulées par la modification du substrat (diélectrique ou métallique), par l'insertion contrôlée d'un défaut dans la cavité ou par le couplage électromagnétique, même faible, entre les deux cavités. L'ingénierie rationnelle de la répartition spatiale des résonances confinées 2D a été appliquée à la conception de dispositifs à transmittance accordable entre deux cavités connectées. Les géométries particulières sont produites par gravure au faisceau d'ions focalisé sur des plaquettes cristallines d'or. Les dispositifs sont caractérisés par cartographie de luminescence non-linéaire en microscopie confocale et en microscopie de fuites. Cette dernière méthode offre un moyen unique d'observer la propagation du signal plasmon dans la cavité. Nous démontrons la dépendance en polarisation de la transmission plasmonique dans les composants à symétrie et géométrie adéquates. Les résultats sont fidèlement reproduits par notre outil de simulation GDM adapté à la configuration de transmission. Enfin, notre approche est appliquée à la conception et à la fabrication d'une porte logique reconfigurable avec plusieurs entrées et sorties. Nous démontrons que dix des douze portes logiques possibles à 2 entrées et 1 sortie sont activable sur une même structure en choisissant les trois points d'entrée et de sortie et en ajustant le seuil de luminescence non-linéaire pour le signal de sortieThe main objective of this PhD work is to design, fabricate and characterize plasmonic devices based on highly crystalline metallic cavities for the two-dimensional information transfer and logic gate operations. First, we thoroughly characterize the optical response of ultra-thin gold colloidal cavities of sub-micronic size (400 to 900 nm) by dark- field spectroscopy (Fig. 1a). The dispersion of the high order plasmonic resonances of the cavities is measured and compared with a good agreement to simulations obtained with a numerical based on the Green Dyadic Method (GDM). We further extend our experiments to systematically tune the spectral responses of these colloidal nanoprisms in vicinity of metallic thin film substrates. A comprehensive study of these sub-micronic size cavity in bowtie antenna configuration is performed. We show a polarization-dependent field enhancement and a nanoscale field confinement at specific locations in these bowtie antennas. We systematically study the effects that could potentially affect the plasmonic resonances by non-linear photon luminescence microscopy, which has proved to be an efficient tool to observe the surface plasmon local density of states (SPLDOS). Inparticular, we show that an effective spatially and spectrally tuning of the high order plasmonic resonances can be achieved by the modification of the substrate (dielectric or metallic), by the controlled insertion of a defect inside a cavity or by the weak electromagnetic coupling between two adjacent cavities. The rational tailoring of the spatial distribution of the 2D confined resonances was applied to the design of devices with tunable plasmon transmittance between two connected cavities. The specific geometries are produced by focused ion milling crystalline gold platelets. The devices are characterized by non-linear luminescence mapping in confocal and leakage radiation microscopy techniques. The latter offers a unique way to observe propagating SPP signal over a 2D plasmonic cavity. We demonstrate the polarization-dependent mode-mediated transmittance for devices withadequate symmetry. The results are faithfully reproduced with our simulation tool based on Green dyadic method. Finally, we extend our approach to the design and fabrication of a reconfigurable logic gate device with multiple inputs and outputs. We demonstrate that 10 out of the possible 12 2-input 1-output logic gates can be implemented on the same structure by choosing the two input and the one output points. We also demonstrate reconfiguration of the device by changing polarization of the incident beam, set of input locations and threshold of the non-linear luminescence readout signal
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Lu, LingFeng. "Modelling of plasma-antenna coupling and non-linear radio frequency wave-plasma-wall interactions in the magnetized plasma device under ion cyclotron range of frequencies". Thesis, Université de Lorraine, 2016. http://www.theses.fr/2016LORR0173/document.
Testo completoAbstract (sommario):
Le Chauffage Cyclotron Ionique (ICRH) par des ondes dans la gamme 30-80MHz est couramment utilisé dans les plasmas de fusion magnétique. Excitées par par des réseaux phasés de rubans de courant à la périphérie du plasma, ces ondes existent sous deux polarisations. L’onde rapide traverse le bord ténu du plasma par effet tunnel puis se propage à son centre où elle est absorbée. L’onde lente, émise de façon parasite, existe seulement à proximité des antennes. Quelle puissance peut être couplée au centre avec 1A de courant sur les rubans? Comment les champs radiofréquence (RF) proches et lointains émis interagissent-ils avec le plasma de bord par rectification de gaine RF à l’interface plasma-paroi? Pour répondre simultanément à ces deux questions, en géométrie réaliste sur l’échelle spatiale des antennes ICRH, cette thèse a amélioré et testé le code numérique SSWICH (Self-consitent Sheaths and Waves for ICH). SSWICH couple de manière auto-cohérente la propagation des ondes RF et la polarisation continue (DC) du plasma via des conditions aux limites non-linéaires de type gaine (SBC) appliquées à l’interface plasma / paroi. La nouvelle version SSWICH-FW est pleine onde et a été développée en deux dimensions (toroïdale/radiale). De nouvelles SBCs couplant les deux polarisations d’ondes ont été obtenues et mises en œuvre le long de parois courbes inclinées par rapport au champ magnétique de confinement. Avec ce nouvel outil en l'absence de SBCs, nous avons étudié l'impact d'une densité décroissant continûment à l'intérieur de la boîte d'antenne en traversant la résonance hybride basse (LH). Dans les limites mémoire de notre poste de travail, les champs RF au-dessous de la résonance LH ont changé avec la taille de maille. Par contre spectre de puissance couplée n’a que très peu évolué, et n’était que faiblement influencé par la densité à l'intérieur de l'antenne. En présence de SBCs, les simulations SSWICH-FW ont identifié le rôle de l'onde rapide sur l’excitation de gaines RF et reproduit certaines observations expérimentales clés. SSWICH-FW a finalement été adapté pour réaliser les premières simulations 2D électromagnétiques et de gaine-RF de la machine plasma cylindrique magnétisée ALINEIon Cyclotron Resonant Heating (ICRH) by waves in 30-80MHz range is currently used in magnetic fusion plasmas. Excited by phased arrays of current straps at the plasma periphery, these waves exist under two polarizations. The Fast Wave tunnels through the tenuous plasma edge and propagates to its center where it is absorbed. The parasitically emitted Slow Wave only exists close to the launchers. How much power can be coupled to the center with 1A current on the straps? How do the emitted radiofrequency (RF) near and far fields interact parasitically with the edge plasma via RF sheath rectification at plasma-wall interfaces? To address these two issues simultaneously, in realistic geometry over the size of ICRH antennas, this thesis upgraded and tested the Self-consistent Sheaths and Waves for ICH (SSWICH) code. SSWICH couples self-consistently RF wave propagation and Direct Current (DC) plasma biasing via non-linear RF and DC sheath boundary conditions (SBCs) at plasma/wall interfaces. Its upgrade is full wave and was implemented in two dimensions (toroidal/radial). New SBCs coupling the two polarizations were derived and implemented along shaped walls tilted with respect to the confinement magnetic field. Using this new tool in the absence of SBCs, we studied the impact of a density decaying continuously inside the antenna box and across the Lower Hybrid (LH) resonance. Up to the memory limits of our workstation, the RF fields below the LH resonance changed with the grid size. However the coupled power spectrum hardly evolved and was only weakly affected by the density inside the box. In presence of SBCs, SSWICH-FW simulations have identified the role of the fast wave on RF sheath excitation and reproduced some key experimental observations. SSWICH-FW was finally adapted to conduct the first electromagnetic and RF-sheath 2D simulations of the cylindrical magnetized plasma device ALINE
9
Manescu, Léonardo-Géo. "L'étude du régime non-sinusoïdal dans les systèmes électriques". Grenoble INPG, 1998. http://www.theses.fr/1998INPG0063.
Testo completoAbstract (sommario):
Dans le cadre de cette thèse on s'est intéressé à l'étude, par simulation, du fonctionnement des systèmes électriques en régime non-sinusoïdal, ainsi qu'aux effets de la pollution harmonique sur les éléments du système. Nous avons tout d'abord révisé les principaux paramètres du régime non-sinusoïdal (en proposant en complément les facteurs de distorsion intégratifs et dérivatifs) et la théorie de la puissance. Ensuite nous avons étudié la modélisation des principaux types de sources d'harmoniques, en adaptant des modèles existants ou en développant de nouveaux (pour les convertisseurs et les TCRs). Nous avons continué avec les éléments linéaires en choisissant parmi leurs modèles ceux appropriés à l'étude du régime non-sinusoïdal ou en proposant des modèles personnels, comme pour les transformateurs de puissance. On a toujours mis en évidence la caractéristique fréquentielle des paramètres des modèles. Après avoir évalué les principes potentiellement utilisables pour la modélisation du fonctionnement du système en régime non-sinusoïdal, nous avons choisi l'analyse harmonique itérative pour des études localisées, dont nous avons amélioré la convergence. Pour les études portant sur l'ensemble du système, nous avons développé un logiciel reposant sur la méthode dichotomique et la représentation hybride (temporelle et fréquentielle) des éléments non-linéaires. Les résultats des simulations réalisées dans le réseau IEEE 14 noeuds modifié, ont été utilisés dans l'analyse des interactions entre les sources harmoniques (principalement à l'aide de la puissance harmonique active totale). Dans la dernière partie, nous avons étudié les principaux types d'effets de la pollution harmonique et nous les avons détaillé pour différentes composantes du systèmeThis thesis deals with the study, by simulation, of power Systems in non-sinusoidal situations including harmonie pollution effects. First the principal parameters of non-sinusoidal wave shapes and working conditions and some éléments of power theory were reviewed. Novel complementary intégrais and derivatives harmonie distortion factors were proposed as well. Secondly, the modelling of the main types of harmonie sources was studied, either by adapting existing models where possible or by designing new models, such for power converters or TCRs. The linear parts of the System where then treated by the appropriated models or making new proposais (as for power transformers). After evaluating the simulation principles of the power Systems operating in non-sinusoidal conditions, itérative harmonie analysis was selected for localised studies, where its convergence properties were improved. For mil scale system studies, a software program was developed based on the dichotomous method, where the hybrid modelling, in both time and frequency domains, of non-linear éléments is assumed. The results of simulations conducted on the IEEE 14-bus modified test network were used in order to analyse the interactions between the harmonie sources, mainly by using the individual and total harmonie active powers. Finally, the principal types of harmonie pollution effects hâve been studied and detailed for several System constituents
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Gotti, Carlo. "Development and mechanical characterization of a biostable Nylon6.6 electrospun nanofibrous multiscale device for tendon and ligament replacement and simulation". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/15708/.
Testo completoAbstract (sommario):
This thesis aims to investigate electrospun structures by means their production process and morpho-mechanical characterization. Considering the results obtained, the electrospun devices developed, will be useful for tendon and ligament tissue applications.
Libri sul tema "Non linear device"
1
Taleghani, Barmac K. Non-linear finite element modeling of Thunder piezoelectric actuators. Hampton, VA: National Aeronautics and Space Administration, Langley Research Center, 1999.
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2
F, Campbell Joel, e Langley Research Center, a cura di. Non-linear finite element modeling of THUNDER piezoelectric actuators. Hampton, Va: National Aeronautics and Space Administration, Langley Research Center, 1999.
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3
Singh, Rajendra. Non-linear dynamic analysis of geared systems. [Columbus, Ohio]: The Ohio State University, Dept. of Mechanical Engineering, 1990.
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4
Singh, Rajendra. Non-linear dynamic analysis of geared systems. [Columbus, Ohio]: The Ohio State University, Dept. of Mechanical Engineering, 1990.
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5
Teat, Simon John. An investigation of KTiOPO4 and its arsenate analogues for use in non-linear devices. [s.l.]: typescript, 1995.
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6
Ling, Chen, e SpringerLink (Online service), a cura di. Structure-Property Relationships in Non-Linear Optical Crystals II: The IR Region. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012.
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7
Ling, Chen, e SpringerLink (Online service), a cura di. Structure-Property Relationships in Non-Linear Optical Crystals I: The UV-Vis Region. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012.
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8
Marchenko, Aleksey, e Mihail Nemcov. Electronics. ru: INFRA-M Academic Publishing LLC., 2023. http://dx.doi.org/10.12737/1587595.
Testo completoAbstract (sommario):
The material of module 2 "Electronics" is systematically presented in
accordance with the modern university program of the discipline "
Electrical Engineering and Electronics" for non-electrotechnical areas of training
of bachelors and certified specialists. The element base
of semiconductor electronics devices is considered: classification,
voltage and frequency characteristics, features of the use
of electronic devices in various operating modes are given.
The principles of construction and functioning of typical analog,
pulse and digital devices are described in detail. A separate chapter is devoted to the principles
of converting light energy into electrical energy and vice versa,
the design and operation of optoelectronic devices and fiber-
optic lines of information transmission.
Meets the requirements of the federal state
educational standards of higher education of the latest generation.
For students of higher educational institutions studying in non-electro-
technical areas of bachelor's and graduate
training.
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Lippiello, Tiziana. Discorso inaugurale della Magnifica Rettrice Anno accademico 2020/2021. Venice: Fondazione Università Ca’ Foscari, 2021. http://dx.doi.org/10.30687/978-88-6969-519-3.
Testo completoAbstract (sommario):
«È ora tempo di uscire dalla logica dell’emergenza e cogliere il futuro come un’opportunità». A un anno dallo scoppio della pandemia, nel primo discorso inaugurale del suo mandato la rettrice Tiziana Lippiello illustra le scelte politiche fondamentali dell’Ateneo e traccia le linee di sviluppo per un domani mai come in questo momento da ripensare e riprogettare. La ricerca, l’investimento sui giovani e sul merito, l’inclusione, la sostenibilità e il rapporto con il territorio sono i temi principali al centro di questo discorso che, per la sua stessa natura non meno che per le eccezionali circostanze in cui è stato pronunciato, intende gettare le basi per un «nuovo inizio», senza mai perdere di vista il legame con il passato e la storia della nostra università, nella consapevolezza che ogni innovazione, per essere veramente tale, deve sapersi confrontare con quella tradizione dalla quale essa stessa discende.
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Murrell, Jonathan Kenneth Jeffrey. Non-linear behaviour of a superconducting quantum interference device coupled to a radio frequency oscillator. 2001.
Cerca il testo completoCapitoli di libri sul tema "Non linear device"
1
Andò, Bruno, e Salvatore Graziani. "Analog Noise Generation via Non-Linear Device". In Stochastic Resonance, 103–20. Boston, MA: Springer US, 2000. http://dx.doi.org/10.1007/978-1-4615-4391-6_4.
Testo completo
2
Prasad, R. "p-n Junction Diode: A Basic Non-linear Device". In Undergraduate Lecture Notes in Physics, 355–456. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-65129-9_5.
Testo completo
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Sule, Nitesh, Daniel Penarete-Acosta, Derek L. Englert e Arul Jayaraman. "A Static Microfluidic Device for Investigating the Chemotaxis Response to Stable, Non-linear Gradients". In Methods in Molecular Biology, 47–59. New York, NY: Springer New York, 2018. http://dx.doi.org/10.1007/978-1-4939-7577-8_5.
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Shejwal, N. N., S. S. Hussaini, Ramesh B. Kamble, Mohd Anis e M. D. Shirsat. "Studies on the Structural, Thermal, Fluorescence and Linear–Non-linear Optical Properties of Glycine Sodium Acetate Single Crystal for Electro-Optic Device Applications". In Springer Proceedings in Physics, 493–501. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-44890-9_45.
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5
Buckley, A., e J. B. Stamatoff. "Non Linear Optical Polymers for Active Optical Devices". In Nonlinear Optical Effects in Organic Polymers, 327–36. Dordrecht: Springer Netherlands, 1989. http://dx.doi.org/10.1007/978-94-009-2295-2_25.
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Feldberg, Rasmus, Carsten Knudsen, Morten Hindsholm e Erik Mosekilde. "Non-Linear Dynamic Phenomena in Electron Transfer Devices". In Computer-Based Management of Complex Systems, 502–8. Berlin, Heidelberg: Springer Berlin Heidelberg, 1989. http://dx.doi.org/10.1007/978-3-642-74946-9_54.
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Ralph, J. F., T. P. Spiller, T. D. Clark, R. J. Prance, H. Prance, A. J. Clippingdale, D. J. Rathbone e M. E. Brooks. "An Analysis of Non-Linear Behaviour in the Radio Frequency SQUID Magnetometer". In Superconducting Devices and Their Applications, 248–51. Berlin, Heidelberg: Springer Berlin Heidelberg, 1992. http://dx.doi.org/10.1007/978-3-642-77457-7_44.
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Gong, Sanpeng, Sebastian Oberst e Xinwen Wang. "A Non-linear Model of Rubber Shear Springs Validated by Experiments". In Nonlinear Dynamics of Structures, Systems and Devices, 319–28. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-34713-0_32.
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Rieß, Simon, Jonas Wiedemann, Sven Coutandin e Jürgen Fleischer. "Secure Clamping of Parts for Disassembly for Remanufacturing". In Annals of Scientific Society for Assembly, Handling and Industrial Robotics 2021, 79–87. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-74032-0_7.
Testo completoAbstract (sommario):
AbstractRobot based remanufacturing of valuable products is commonly perceived as promising field in future in terms of an efficient and globally competitive economy. Additionally, it plays an important role with regard to resource-efficient manufacturing. The associated processes however, require a reliable non-destructive disassembly. For these disassembly processes, there is special robot periphery essential to enable the tasks physically. Unlike manufacturing, within remanufacturing there are End-of-Life (EoL) products utilized. The specifications and conditions are often uncertain and varying. Consequently the robot system and especially the periphery needs to adapt to the used product, based on an initial examination and classification of the part. State of the art approaches provide limited flexibility and adaptability to the disassembly of electric motors used in automotive industry. Especially the geometrical shape is a limiting factor for using state of the art periphery for remanufacturing. Within this contribution a new kind of flexible clamping device for the disassembly of EoL electrical motors is presented. The robot periphery is systematically developed regarding the requirements stemming from the remanufacturing approach. It consists of three clamping units with moveable pins. Utilizing two linear axes, a two dimensional working space is realized for clamping the parts depending on their conditions and shape.
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Bermejo, F. J., P. García Fernández, P. Colet, S. Balle, R. Toral e M. San Miguel. "Langevin Equations for Squeezing by Means of Non-linear Optical Devices". In Springer Proceedings in Physics, 65–73. Berlin, Heidelberg: Springer Berlin Heidelberg, 1991. http://dx.doi.org/10.1007/978-3-642-76373-1_8.
Testo completoAtti di convegni sul tema "Non linear device"
1
Cuoco, V., M. de Kok, M. P. v. d. Heijden e L. C. N. de Vreede. "Isothermal Non-Linear Device Characterization". In 58th ARFTG Conference Digest. IEEE, 2001. http://dx.doi.org/10.1109/arftg.2001.327493.
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2
Preisler, E., W. Cai, Jie Zheng e M. Racanelli. "Simulations of Non-Uniform, Non-Linear Collector Doping Profiles for SiGe HBTs". In 2006 International SiGe Technology and Device Meeting. IEEE, 2006. http://dx.doi.org/10.1109/istdm.2006.246512.
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Baglioni, Stefano, Claudio Braccesi, Filippo Cianetti, Antonio Ficola e Carmelo Anile. "Design of a Biomedical Device Through Non Linear Analysis". In ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-51765.
Testo completoAbstract (sommario):
The most widely accepted hypothesis to explain normal pressure hydrocephalus (NPH) points at the increase of cerebrospinal fluid (CSF) outflow resistance as the fundamental cause. Some clinical and experimental studies do not agree with this hypothesis and suggest that NPH is related to an alteration of the CSF pulse pressure waveform, while intracranial pressure (ICP) mean value has negligible effects. The current treatment of hydrocephalus is based on the first hypothesis and consists in the implantation of CSF shunts. An improved treatment can be obtained by damping the ICP pressure peaks and keeping unchanged the mean value. The target of this work is to design a special ICP regulator valve, that will be implanted in a human body and that must be characterized by a purely mechanical working principle avoiding any electrical equipment (sensors, actuators...). This device is currently patented [1] and in virtue of that the paper will focus only on the general device working principle and design methodology rather than specific data. Since the device must be implanted inside the patient head, the system must satisfy very restrictive requirements: low weight and dimensions in order to avoid possible patient discomfort or obstacles to the normal life activities, in addition, being the valve application place close to a delicate organ such the brain is, the mechanism must be very simple and must reach very high reliability standards (almost zero maintenance and possible failures). The idea is to realize a device in which the hydraulic flow is governed by a spring with variable stiffness with respect to the applied loads (intracranial pressure: characterized by both a mean constant component and by random oscillatory phenomenon). To maximize the valve effect about pressure peaks reduction, the spring will be designed with a strongly non-linear behavior characterized by bistable working principle. The systems that show this properties are innumerable, but according to the author hypothesis to realize a mechanism as simpler as possible the choice done falls into the thin curved plate (shell) category. In particular, the goal is to obtain a plate behavior called “Buckling Behavior”: under determined load conditions the plate geometric configuration must suddenly switch from an equilibrium position to another. The two target parameters which describe this phenomenon are the buckling critical load that is the applied load value for which the plate change the geometric configuration (valve activation point) and the load application point displacement (evacuation pipe opening). The adopted design method is the non-linear analysis developed in a finite element analysis (F.E.A.) environment, by which it is possible to analyze a component behavior also in case of large displacements. To identify the optimal component geometry the load application point displacement versus the acting load was evaluated as function of the main parameters describing the plate profile: plate semi-length, curvature radius and semi-length of the plate plane portion. This work represents only a preliminary study oriented to demonstrate the feasibility in realizing a biomedical valve for fluids pressure control, adopting a thin curved plate with “Buckling Behavior”. Moreover it provides useful information for the designer who wants to realize curved plate with buckling behavior showing the influence of the main geometric parameters on this phenomenon. Further in depth studies oriented to: the spring stiffness regulation for different patients, best material choice and productive process must be accomplished before the device realization.
4
Schreurs, Dominique. "Systematic Evaluation of Non-Linear Microwave Device and Amplifier Models". In 2006 European Microwave Integrated Circuits Conference. IEEE, 2006. http://dx.doi.org/10.1109/emicc.2006.282802.
Testo completo
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Kaienburg, Pascal, Paula Hartnagel, Bart E. Pieters, David Grabowski, Jiaoxian Yu e Thomas Kirchartz. "Impact of Non-linear Shunts from Pinholes on Device Performance". In 10th International Conference on Hybrid and Organic Photovoltaics. Valencia: Fundació Scito, 2018. http://dx.doi.org/10.29363/nanoge.hopv.2018.112.
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Ferrero, Andrea, e Valeria Teppati. "A complete measurement Test-Set for non-linear device characterization". In 58th ARFTG Conference Digest. IEEE, 2001. http://dx.doi.org/10.1109/arftg.2001.327494.
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Guo, Lei, Wei Chen, Yuxuan Sun e Bo Ai. "Device-Edge Digital Semantic Communication with Trained Non-Linear Quantization". In 2023 IEEE 97th Vehicular Technology Conference (VTC2023-Spring). IEEE, 2023. http://dx.doi.org/10.1109/vtc2023-spring57618.2023.10200355.
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Csaba, Gyorgy, Adam Papp, Wolfgang Porod e Ramazan Yeniceri. "Non-boolean computing based on linear waves and oscillators". In ESSDERC 2015 - 45th European Solid-State Device Research Conference. IEEE, 2015. http://dx.doi.org/10.1109/essderc.2015.7324723.
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Lambkin, P., e K. A. Shore. "Non-linear optical waveguiding in semiconductors". In Optical Bistability. Washington, D.C.: Optica Publishing Group, 1988. http://dx.doi.org/10.1364/obi.1988.fb.4.
Testo completoAbstract (sommario):
Practical device implementations of non-linear waveguides may utilise the defocussing non-linearity associated with the fundamental absorption edge of semiconductors. A suitable slab waveguide structure would involve a non-linear guiding layer bounded by cladding layers which are non-absorbing and hence linear at the operating wavelength. An analysis of TE modes in such a structure is given for the first time in this paper.
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Pungetmongkol, Porpin, Katsuo Mogi e Takatoki Yamamoto. "Conformation dependent non-linear impedance response of DNA in nanofluidic device". In 2015 IEEE 15th International Conference on Nanotechnology (IEEE-NANO). IEEE, 2015. http://dx.doi.org/10.1109/nano.2015.7388832.
Testo completoRapporti di organizzazioni sul tema "Non linear device"
1
Hamlin, Alexandra, Erik Kobylarz, James Lever, Susan Taylor e Laura Ray. Assessing the feasibility of detecting epileptic seizures using non-cerebral sensor. Engineer Research and Development Center (U.S.), dicembre 2021. http://dx.doi.org/10.21079/11681/42562.
Testo completoAbstract (sommario):
This paper investigates the feasibility of using non-cerebral, time-series data to detect epileptic seizures. Data were recorded from fifteen patients (7 male, 5 female, 3 not noted, mean age 36.17 yrs), five of whom had a total of seven seizures. Patients were monitored in an inpatient setting using standard video electroencephalography (vEEG), while also wearing sensors monitoring electrocardiography, electrodermal activity, electromyography, accelerometry, and audio signals (vocalizations). A systematic and detailed study was conducted to identify the sensors and the features derived from the non-cerebral sensors that contribute most significantly to separability of data acquired during seizures from non-seizure data. Post-processing of the data using linear discriminant analysis (LDA) shows that seizure data are strongly separable from non-seizure data based on features derived from the signals recorded. The mean area under the receiver operator characteristic (ROC) curve for each individual patient that experienced a seizure during data collection, calculated using LDA, was 0.9682. The features that contribute most significantly to seizure detection differ for each patient. The results show that a multimodal approach to seizure detection using the specified sensor suite is promising in detecting seizures with both sensitivity and specificity. Moreover, the study provides a means to quantify the contribution of each sensor and feature to separability. Development of a non-electroencephalography (EEG) based seizure detection device would give doctors a more accurate seizure count outside of the clinical setting, improving treatment and the quality of life of epilepsy patients.
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Villamil, Julie, Caique Lara, Anthony Abrahao, Aparna Arvelli, Guilherme Daldegan, Sharif Sarker e Dwayne McDaniel. Development of a Pipe Crawler Inspection Tool for Fossil Energy Power Plants. Florida International University, ottobre 2021. http://dx.doi.org/10.25148/mmeurs.009772.
Testo completoAbstract (sommario):
Fossil fuel power plants are complex systems containing multiple components that create extreme environments for the purpose of extracting usable energy. Failures in the system can lead to increased down time for the plant, reduction of power and significant cost for repairs. In the past, inspections and maintenance of the plant's superheater tubes has been predominantly manual, laborious, and extremely time consuming. This is due to the pipe's small diameter size (between 1.3 and 7.6 cm) and the coiled structure of the tubing. In addition, the tubes are often stacked close to each other, limiting access for external inspection. Detection of pipe degradation, such as increased levels of corrosion, creep, and the formation of micro-cracks is possible using standard non-destructive evaluation (NDE) methods, including ultrasonic, radiography and electromagnetic methods. However, when the access to the sub-systems is limited or the configuration of the structure is prohibitive, alternative methods are needed for deploying the NDE tools. This research effort considers a novel robotic inspection system for the evaluation of small pipes found in typical boiler superheaters that have limited access. The pipe crawler system is an internal inspection device that can potentially navigate through the entire pipe length using linear actuators to grip the walls and inch along the pipe. The modular nature of the system allows it to traverse through straight sections and multiple 90-degree and 180-degree bends. The crawler is also capable of providing visual inspections, ultrasonic thickness measurements, and generating inner diameter surface maps using LiDAR (light detection and ranging). Ultimately, the development of this robotic inspection tool can provide information regarding the structural integrity of key pipeline components in fossil fuel power plants that are not easily accessible
3
Britt, Jack, Miriam Rosenberg, Steven Washburn e Moshe Kaim. Development and Evaluation of a Method of Hormonal Treatment to Increase Fertility in Dairy Cows. United States Department of Agriculture, dicembre 1995. http://dx.doi.org/10.32747/1995.7612833.bard.
Testo completoAbstract (sommario):
The objectives were: 1) to develop a practical method for improving conception rates of dairy cows by administering progesterone during the critical period of the luteal phase prior to first insemination, 2) to determine which cows respond best to such a progesterone treatment, and 3) to determine physiological changes that are associated with this treatment. Experiment 1, conducted in the US and Israel, tested three treatment protocols. Holstein cows: 1) served as controls, 2) received two injections of prostaglanding F2a (PGF) 14 days apart, or 3) received two PGF injections and were inserted with a progesterone releasing intravaginal device (PRID) for 6 days beginning 9 days after the first injection of PGF. Fertility was positively related to plasma progesterone concentations prior to the second PGF injection, but PRID treatment did not improve fertility in cows with low progesterone. Cows in synchronized estrus 2-8 days after the second injection of PGF had higher fertility and better reproductive performance than non-synchronized cows. Experiment 3, conducted in Israel, involved three studies that assessed effect of PRID treatment on: 1) progesterone concentration in ovarian tissue and uterine tissue and fluids, 2) changes in systemic LH and estradiol, and 3) development and function of dominant follicles. Treatment with PRID increased progesterone in uterine tissue and fluid exclusive of effects on systemic concentrations. Low progesterone resulted in persistent follicles that exceeded normal size and produced excessive estrogen. Experiment 4, conducted in the US, evaluated influence of endogenous progesterone on embryo development. Cows were given two injections of PGF 14 days apart and single embryos were recovered 7 days after estrus. Among cyclic cows, there was a linear relationship between progesterone concentration and percentage of cows from which an embryo was recovered. Overall these experiments show that systemic progesterone concentrations affect fertility in high-producing dairy cows through effects on follicular development and embryo survival
4
Davis. L51674 In-Line Inspection Device for Stress Corrosion Cracks. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), dicembre 1992. http://dx.doi.org/10.55274/r0010617.
Testo completoAbstract (sommario):
�Under previous programs for the Pipeline Research Committee, field tested a low frequency eddy current instrument for detecting and characterizing stress corrosion cracks in pipelines was developed. While a significant improvement over conventional magnetic particle inspections in some respects, the eddy current method as it was developed in these programs can only be used with surface breaking defects. Thus, it is limited to use for inspections of pipelines from the outside surface. In this program, we examined the use of a saturating magnetic field to allow increased penetration of the eddy current field into the pipe material, providing the ability to detect and characterize stress corrosion cracks from the interior of the pipeline. Until recently, eddy current inspections of steel were the exception not the norm, primarily because low frequency eddy current instruments were not available. In eddy current testing, the eddy current field grows smaller as it penetrates into the material being tested.
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O'Connell, R. F. Quantum Transport, Noise and Non-Linear Dissipative Effects in One- and Two-Dimensional Systems and Associated Sub-Micron and Nanostructure Devices. Fort Belvoir, VA: Defense Technical Information Center, gennaio 1992. http://dx.doi.org/10.21236/ada250895.
Testo completo
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Ellor, James A., P.E., J. Peter Ault e P.E. PR-543-153601-R01 The Effects of Spray Polyurethane Foam on the Cathodic Protection of Pipelines. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), marzo 2017. http://dx.doi.org/10.55274/r0011022.
Testo completoAbstract (sommario):
The current program examined the use of structural spray polyurethane foams (SPF) used in the pipeline industry as line supports (foam ditch pads) or as erosion-control devices (foam trench breakers). Of concern are requirements that pipelines are protected by �non-shielding� coatings and that cathodic protection design must consider �electrical shielding.� Cathodic protection current may pass through or around the foams depending on the foam properties, surrounding electrolyte conductivity, and foam bonding to the pipeline. The program studied SPF impacts on cathodic protection of simulated under-ground steel pipelines.
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Lovianova, Iryna V., Dmytro Ye Bobyliev e Aleksandr D. Uchitel. Cloud calculations within the optional course Optimization Problems for 10th-11th graders. [б. в.], settembre 2019. http://dx.doi.org/10.31812/123456789/3267.
Testo completoAbstract (sommario):
The article deals with the problem of introducing cloud calculations into 10th-11th graders’ training to solve optimization problems in the context of the STEM-education concept. After analyzing existing programmes of optional courses on optimization problems, the programme of the optional course Optimization Problems has been developed and substantiated implying solution of problems by the cloud environment CoCalc. It is a routine calculating operation and not a mathematical model that is accentuated in the programme. It allows considering more problems which are close to reality without adapting the material while training 10th-11th graders. Besides, the mathematical apparatus of the course which is partially known to students as the knowledge acquired from such mathematics sections as the theory of probability, mathematical statistics, mathematical analysis and linear algebra is enough to master the suggested course. The developed course deals with a whole class of problems of conventional optimization which vary greatly. They can be associated with designing devices and technological processes, distributing limited resources and planning business functioning as well as with everyday problems of people. Devices, processes and situations to which a model of optimization problem is applied are called optimization problems. Optimization methods enable optimal solutions for mathematical models. The developed course is noted for building mathematical models and defining a method to be applied to finding an efficient solution.
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Chauhan e Wood. L52007 Experimental Validation of Methods for Assessing Closely Spaced Corrosion Defects. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), marzo 2005. http://dx.doi.org/10.55274/r0011167.
Testo completoAbstract (sommario):
A full-scale burst test program was devised and agreed with the PRCI Materials Technical Committee Ad Hoc group. The work was undertaken over a two year period, 2003 and 2004. Due to budget constraints, only one pipe diameter and material was chosen for the test program. This was 24� (610 mm) outside diameter (OD) by 7.9 mm wall thickness, welded ERW steel linepipe of material API 5L grade B/X42. The criterion that defects separated by a distance of 6t or less will interact is over conservative. New rules for interaction, derived using non-linear finite element analyses and validated using full scale burst testing, have been derived for closely spaced metal loss interacting defects in pipelines. New, robust interaction rules for assessing corrosion metal loss defects in pipelines have been formulated for use by the pipeline industry.
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Galili, Naftali, Roger P. Rohrbach, Itzhak Shmulevich, Yoram Fuchs e Giora Zauberman. Non-Destructive Quality Sensing of High-Value Agricultural Commodities Through Response Analysis. United States Department of Agriculture, ottobre 1994. http://dx.doi.org/10.32747/1994.7570549.bard.
Testo completoAbstract (sommario):
The objectives of this project were to develop nondestructive methods for detection of internal properties and firmness of fruits and vegetables. One method was based on a soft piezoelectric film transducer developed in the Technion, for analysis of fruit response to low-energy excitation. The second method was a dot-matrix piezoelectric transducer of North Carolina State University, developed for contact-pressure analysis of fruit during impact. Two research teams, one in Israel and the other in North Carolina, coordinated their research effort according to the specific objectives of the project, to develop and apply the two complementary methods for quality control of agricultural commodities. In Israel: An improved firmness testing system was developed and tested with tropical fruits. The new system included an instrumented fruit-bed of three flexible piezoelectric sensors and miniature electromagnetic hammers, which served as fruit support and low-energy excitation device, respectively. Resonant frequencies were detected for determination of firmness index. Two new acoustic parameters were developed for evaluation of fruit firmness and maturity: a dumping-ratio and a centeroid of the frequency response. Experiments were performed with avocado and mango fruits. The internal damping ratio, which may indicate fruit ripeness, increased monotonically with time, while resonant frequencies and firmness indices decreased with time. Fruit samples were tested daily by destructive penetration test. A fairy high correlation was found in tropical fruits between the penetration force and the new acoustic parameters; a lower correlation was found between this parameter and the conventional firmness index. Improved table-top firmness testing units, Firmalon, with data-logging system and on-line data analysis capacity have been built. The new device was used for the full-scale experiments in the next two years, ahead of the original program and BARD timetable. Close cooperation was initiated with local industry for development of both off-line and on-line sorting and quality control of more agricultural commodities. Firmalon units were produced and operated in major packaging houses in Israel, Belgium and Washington State, on mango and avocado, apples, pears, tomatoes, melons and some other fruits, to gain field experience with the new method. The accumulated experimental data from all these activities is still analyzed, to improve firmness sorting criteria and shelf-life predicting curves for the different fruits. The test program in commercial CA storage facilities in Washington State included seven apple varieties: Fuji, Braeburn, Gala, Granny Smith, Jonagold, Red Delicious, Golden Delicious, and D'Anjou pear variety. FI master-curves could be developed for the Braeburn, Gala, Granny Smith and Jonagold apples. These fruits showed a steady ripening process during the test period. Yet, more work should be conducted to reduce scattering of the data and to determine the confidence limits of the method. Nearly constant FI in Red Delicious and the fluctuations of FI in the Fuji apples should be re-examined. Three sets of experiment were performed with Flandria tomatoes. Despite the complex structure of the tomatoes, the acoustic method could be used for firmness evaluation and to follow the ripening evolution with time. Close agreement was achieved between the auction expert evaluation and that of the nondestructive acoustic test, where firmness index of 4.0 and more indicated grade-A tomatoes. More work is performed to refine the sorting algorithm and to develop a general ripening scale for automatic grading of tomatoes for the fresh fruit market. Galia melons were tested in Israel, in simulated export conditions. It was concluded that the Firmalon is capable of detecting the ripening of melons nondestructively, and sorted out the defective fruits from the export shipment. The cooperation with local industry resulted in development of automatic on-line prototype of the acoustic sensor, that may be incorporated with the export quality control system for melons. More interesting is the development of the remote firmness sensing method for sealed CA cool-rooms, where most of the full-year fruit yield in stored for off-season consumption. Hundreds of ripening monitor systems have been installed in major fruit storage facilities, and being evaluated now by the consumers. If successful, the new method may cause a major change in long-term fruit storage technology. More uses of the acoustic test method have been considered, for monitoring fruit maturity and harvest time, testing fruit samples or each individual fruit when entering the storage facilities, packaging house and auction, and in the supermarket. This approach may result in a full line of equipment for nondestructive quality control of fruits and vegetables, from the orchard or the greenhouse, through the entire sorting, grading and storage process, up to the consumer table. The developed technology offers a tool to determine the maturity of the fruits nondestructively by monitoring their acoustic response to mechanical impulse on the tree. A special device was built and preliminary tested in mango fruit. More development is needed to develop a portable, hand operated sensing method for this purpose. In North Carolina: Analysis method based on an Auto-Regressive (AR) model was developed for detecting the first resonance of fruit from their response to mechanical impulse. The algorithm included a routine that detects the first resonant frequency from as many sensors as possible. Experiments on Red Delicious apples were performed and their firmness was determined. The AR method allowed the detection of the first resonance. The method could be fast enough to be utilized in a real time sorting machine. Yet, further study is needed to look for improvement of the search algorithm of the methods. An impact contact-pressure measurement system and Neural Network (NN) identification method were developed to investigate the relationships between surface pressure distributions on selected fruits and their respective internal textural qualities. A piezoelectric dot-matrix pressure transducer was developed for the purpose of acquiring time-sampled pressure profiles during impact. The acquired data was transferred into a personal computer and accurate visualization of animated data were presented. Preliminary test with 10 apples has been performed. Measurement were made by the contact-pressure transducer in two different positions. Complementary measurements were made on the same apples by using the Firmalon and Magness Taylor (MT) testers. Three-layer neural network was designed. 2/3 of the contact-pressure data were used as training input data and corresponding MT data as training target data. The remaining data were used as NN checking data. Six samples randomly chosen from the ten measured samples and their corresponding Firmalon values were used as the NN training and target data, respectively. The remaining four samples' data were input to the NN. The NN results consistent with the Firmness Tester values. So, if more training data would be obtained, the output should be more accurate. In addition, the Firmness Tester values do not consistent with MT firmness tester values. The NN method developed in this study appears to be a useful tool to emulate the MT Firmness test results without destroying the apple samples. To get more accurate estimation of MT firmness a much larger training data set is required. When the larger sensitive area of the pressure sensor being developed in this project becomes available, the entire contact 'shape' will provide additional information and the neural network results would be more accurate. It has been shown that the impact information can be utilized in the determination of internal quality factors of fruit. Until now,
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Ukiwe e McDonnell. L52362 Assessing the Performance of Above Ground Coating Evaluation Surveys. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), novembre 2012. http://dx.doi.org/10.55274/r0010686.
Testo completoAbstract (sommario):
The primary application area for above ground coating evaluation (AGCES) methods is for unpiggable pipelines. For several reasons, however, AGCES methods are not necessarily limited along these narrow lines. For instance, most ILI tools are incapable of identifying external corrosion (which resulted from coating damage overtime) until the wall loss damage has reached the measurable detection threshold of the ILI tool. Thus, even for piggable pipelines, AGCES methods still come in handy for pipeline integrity. In fact, the most proactive approach for pipeline corrosion integrity management for the future will include complementary surveys, such as ECDA and ICDA, all super-imposed and integrated on a common GIS framework for comparative and comprehensive data analysis. Within the pipeline industry there exist divergent views about the AGCES methods, their principles of operation, and limitations. An important defining point about AGCES methods is simple this: they are indirect inspection methods for identifying and classifying external coating damage; they are not - and should not be - tied to the functionalities of any specific proprietary tools or hardware manufactures. The second statement requires further qualification. Confusion is often created among users of AGCES methods when the names of certain coating survey tool are interchanged with the specific survey methods in question. For instance, company A manufactures a device C for detecting coating anomalies. The tendency within the industry is to call the coating survey method such names as "C Survey" or "C Coating Survey". The problem created in this instance is to limit AGCES methods to what device C can capture; the quality of the data become handicapped by that of device C. Industry standards have been created to avoid the fore-going pitfalls. Hence, rather than limit survey methods to the specifications of a given proprietary tool, attempts should be made to manufacture and design tools to meet industry standards. The result will be uniformity of methodology, the only distinctions being speed of data acquisition, methods of data analysis, and possibly, other subtle differences in technological advancements. Included in this distinction is the use of analog versus digital data acquisition methods. Of course, all that has been described so far assumes that the industry standards referenced captures all the details of an effective coating evaluation survey method, including known and even perceived limitations.