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Статті в журналах з теми "Short Circuit turn to turn"
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Aubert, Brice, Jérémi Régnier, Stéphane Caux, and Dominique Alejo. "Stator Winding Fault Diagnosis in Permanent Magnet Synchronous Generators Based on Short-Circuited Turns Identification Using Extended Kalman Filter." ACTA IMEKO 3, no. 4 (December 1, 2014): 4. http://dx.doi.org/10.21014/acta_imeko.v3i4.146.
Повний текст джерелаАнотація:
<p class="Abstract">This paper deals with an Extended Kalman Filter based fault detection for inter-turn short-circuit in Permanent Magnet Synchronous Generators. Inter-turn short-circuits are among the most critical faults in the PMSG. Indeed, due to permanent magnets, the short-circuit current is maintained as long as the machine is rotating. Thus, a specific faulty model in d-q frame is developed to estimate the number of short-circuited turns which are used to build a fault indicator. Simulation results demonstrate the sensitivity and the robustness of the proposed fault indicator against various operation points on an electrical network even for a few number of short-circuited turns.</p>
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Nacera, Yassa, Houassine Hamza, Ouadfel Ghania, and Rachek Mhemed. "Multi-Turn Modeling of a Power Transformer under an Inter-Turn Short-Circuit Fault." European Journal of Electrical Engineering 24, no. 2 (April 30, 2022): 89–96. http://dx.doi.org/10.18280/ejee.240203.
Повний текст джерелаАнотація:
This paper presents a new method for modeling the steady-state behavior of the currents transmitted between the windings of a transformer subjected to an inter-turn short-circuit fault (ITSC). ITSC is one of the most frequent and most damaging faults in magnetically coupled circuits, which occur in power transformers. Coupled Electromagnetic Circuit (CEMC) Model modeling the reasoning and relationships describing the operating principle of a power transformer through the electrical and magnetic parameters defined by the self and mutual inductances that influence the voltages and currents transmitted between the transformer windings. The representation of the state variable equations of a proposed model of a three-phase multi-turn transformer in healthy mode (no fault) and in degraded mode (with inter-turn short-circuit faults of 10%, 20% and 30%) has been implemented using a program inserted in MATLAB software. The simulations illustrate the evaluation of the primary and secondary currents as well as the voltage drop across a load, and the accuracy of the state model based on the coupled circuits was validated. The results obtained can provide a basis for the design of the short circuit of the multi-turn transformer.
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Arumugam, Puvan, Tahar Hamiti, and Chris Gerada. "Turn–turn short circuit fault management in permanent magnet machines." IET Electric Power Applications 9, no. 9 (November 2015): 634–41. http://dx.doi.org/10.1049/iet-epa.2015.0020.
Повний текст джерела
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Quan, Yu Sheng, Zong Cheng Zhang, Guang Chen, and Dai Juan Wang. "Study on Method Detecting Turn-to-Turn Short Circuit of Transformer Based on Kalman Filter." Applied Mechanics and Materials 521 (February 2014): 371–74. http://dx.doi.org/10.4028/www.scientific.net/amm.521.371.
Повний текст джерелаАнотація:
Distribution transformer is an important device in the power system, once its failure can cause power outages. According to statistics, 70% -80% of the transformer accident was caused by a short circuit between the transformer turns. In this paper, the ground current of transformer core as the signal source, using Kalman filter techniques to approximate the measured signal, obtained state transition parameters of the prediction signal that most approximate the signal measured , Generated the inter-turn short circuit fault diagnostic parameters, based on the range of parameters to achieve the transformer inter-turn short circuits fault diagnosis. To verify this method, this paper design experiment, the results prove the validity and feasibility of the methods for fault diagnosis.
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Quan, Yu Sheng, Xin Zhao, Guang Chen, and En Ze Zhou. "Study on Methodology Detecting Turn-to-Turn Short Circuit of Transformer." Advanced Materials Research 805-806 (September 2013): 876–79. http://dx.doi.org/10.4028/www.scientific.net/amr.805-806.876.
Повний текст джерелаАнотація:
A novel method for detecting turn-to-turn short circuit is proposed in this paper. This detection makes the transient voltage and current applied in the transformer port as the information source. The transformer model is structured according to its low-frequency characteristics. By comparison the extreme value of the criterion function proposed in this paper, the transformer turn-to-turn short circuit fault can be detected. Based on good results in the simulation, the methodology is proved effective and practical.
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Pietrowski, Wojciech, and Konrad Górny. "Analysis of Torque Ripples of an Induction Motor Taking into Account a Inter-Turn Short-Circuit in a Stator Winding." Energies 13, no. 14 (July 14, 2020): 3626. http://dx.doi.org/10.3390/en13143626.
Повний текст джерелаАнотація:
Despite the increasing popularity of permanent magnet synchronous machines, induction motors (IM) are still the most frequently used electrical machines in commercial applications. Ensuring a failure-free operation of IM motivates research aimed at the development of effective methods of monitoring and diagnostic of electrical machines. The presented paper deals with diagnostics of an IM with failure of an inter-turn short-circuit in a stator winding. As this type of failure commonly does not lead immediately to exclusion of a drive system, an early stage diagnosis of inter-turn short-circuit enables preventive maintenance and reduce the costs of a whole drive system failure. In the proposed approach, the early diagnostics of IM with the inter-turn short-circuit is based on the analysis of an electromagnetic torque waveform. The research is based on an elaborated numerical field–circuit model of IM. In the presented model, the inter-turn short-circuit in the selected winding has been accounted for. As the short-circuit between the turns can occur in different locations in coils of winding, computations were carried out for various quantity of shorted turns in the winding. The performed analysis of impact of inter-turn short-circuit on torque waveforms allowed to find the correlation between the quantity of shorted turns and torque ripple level. This correlation can be used as input into the first layer of an artificial neural network in early and noninvasive diagnostics of drive systems.
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Wu, Yucai, and Guanhua Ma. "Anti-Interference and Location Performance for Turn-to-Turn Short Circuit Detection in Turbo-Generator Rotor Windings." Energies 12, no. 7 (April 10, 2019): 1378. http://dx.doi.org/10.3390/en12071378.
Повний текст джерелаАнотація:
Online and location detection of rotor winding inter-turn short circuits are an important direction in the field of fault diagnosis in turbo-generators. This area is facing many difficulties and challenges. This study is based on the principles associated with the U-shaped detection coil method. Compared with dynamic eccentricity faults, the characteristics of the variations in the main magnetic field after a turn-to-turn short circuit in rotor windings were analyzed and the unique characteristics were extracted. We propose that the degree of a turn-to-turn short circuit can be judged by the difference in the induction voltage of the double U-shaped detection coils mounted on the stator core. Here, the faulty slot position was determined by the local convex point formed by the difference in the induced voltage. Numerical simulation was used here to determine the induced voltage characteristics in the double U-shaped coils caused by the turn-to-turn short circuit fault. We analyzed the dynamic eccentricity fault as well as combined the fault of a turn-to-turn short circuit and dynamic eccentricity. Finally, we demonstrate the positive anti-interference performance associated with this fault detection method. This new online detection method is satisfactory in terms of sensitivity, speed, and positioning, and overall performance is superior to the traditional online detection methods.
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Nedelchev, Nedelcho, and Misho Matsankov. "Increasing the Sensitivity of the Digital Relay Protection Against Turn-to-turn Short Circuits And Asymmetries In Wind Power Generators." E3S Web of Conferences 186 (2020): 03001. http://dx.doi.org/10.1051/e3sconf/202018603001.
Повний текст джерелаАнотація:
The paper describes the implementation of neural networks for increasing the sensitivity of the digital relay protection against turn-to turn short circuits in the stator winding and asymmetric modes in wind power generators. Models have been developed for monitoring two standard and two emergency mode parameters, whose deviation from the set-points is an indication of occurrence of turn-to-turn short circuits and asymmetric modes, or of combinations of these types of failures. An artificial neural network, trained by error back-propagation algorithm has been used. An experiment has been conducted to define the four criteria for studying the problem at different percentage of the short-circuit turns. A comparison between the results from both the experiment and the modeling has been made using artificial neural networks. The proposed approach, realized by means of a digital relay, allows for increasing the sensitivity of the digital relay protection against turn-to-turn short circuits and asymmetric modes for wind power generators.
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AFANAS’YEV, Alexander A. "Equations of a magnetoelectric valve motor for loop closures of the stator winding." Elektrichestvo 11, no. 11 (2020): 47–52. http://dx.doi.org/10.24160/0013-5380-2020-11-47-52.
Повний текст джерелаАнотація:
The article considers the differential equations of a switched permanent magnet motor in which a short-circuit fault occurred in one or more turns in one of parallel stator winding branches. Owing to the occurred asymmetry of the phase quantities, symmetrical line-to-line voltages at the stator winding terminals are assumed. It is shown that turn-to-turn short-circuit faults give rise to non-sinusoidal and imbalanced phase currents and voltages at the nominal load torque on the shaft, and it should be noted that initially, a growth of the frequency and ratios of currents in the phases with an increase in the number of short-circuited turns are observed, after which the phase currents tend to decrease (with a continuing growth in the current through the short-circuited loop), and the rotor stalling occurs. The growth of motor rotation frequency and decrease of its overloading capacity take place due to a growth in the demagnetizing effect of armature reaction caused by the current through the short-circuited stator winding turns.
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Polishchuk, V. I., E. O. Kuleshova, and Yu Z. Vasilyeva. "Turn-to-Turn Short Circuit Diagnostic Improvement Method Based on ANN for Synchronous Generator Excitation Winding." Applied Mechanics and Materials 792 (September 2015): 51–55. http://dx.doi.org/10.4028/www.scientific.net/amm.792.51.
Повний текст джерелаАнотація:
The paper describes the determination method of quasi-reactive power for synchronous generator turn-to-turn short circuit diagnostics. A proposed method allows to determine the relation between the exciting current and quasi-reactive power at the generator leading to a high probability. This relation is the basis of the determination method of turn-to-turn short circuit availability and its severity.
Дисертації з теми "Short Circuit turn to turn"
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Babu, Hareesh. "Finite-element analysis of an induction motor with inter-turn short-circuit faults." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-290082.
Повний текст джерелаАнотація:
Stator inter-turn short circuit (ITSC) faults are one of the common sources for induction machine failure affecting their reliable operation. In this thesis, a finite element (FE) model is developed to study the ITSC fault. The FE model is developed for a prototype induction machine that has the potential to emulate an ITSC fault in the stator. With the developed FE model of the prototype machine, a simulation study is performed to understand the behaviour of various electrical and magnetic quantities in time- and frequency-domain. The investigated quantities are potentially good signatures of the stator winding faults and they are therefore suitable to use in a condition monitoring system. The prototype machine with ITSC faults has been tested in an experimental setup and the results are compared to the simulation and also to analytical results. For the fault current it was found a good agreement between analytical results, FE simulations and experimental results. Moreover, the FE simulation results of the negative-sequence stator current amplitude present a minor mismatch with the analytical and experimental results. The reason for this mismatch is due to an inaccurate knowledge of the prototype machine geometrical parameters.Kortslutning mellan varven i en asynkronmotors statorlindning (ITSC) är en av de vanligaste källorna för fel som påverkar dess drifttillförlitlighet. I detta examensarbete utvecklas en finit-element (FE) modell för att studera ITSC- fel. FE-modellen är utvecklad för en asynkronmotorprototyp som kan emulera ITSC-fel. Med den utvecklade modellen utförs en simuleringsstudie för att förstå beteendet hos olika elektriska och magnetiska egenskaper både i tids- och frekvensdomän. Dessa egenskaper är goda indikatorer av statorlindningsfel och kan därför med fördel användas i ett tillståndsövervakningssystem. Prototypmaskinen har testats experimentellt och de erhållna resultaten jämförs med FE-simuleringen och analysresultaten. Det analytiska resultatet, FEM- simuleringarna och den experimentella utvärderingen uppvisade god överrensstämmelse vad gäller felströmmen. Dock finns det en mindre avvikelse när det gäller amplituden hos statorströmmens negativa fasföljd. Orsaken till denna avvikelse är att prototypmaskinens geometri inte är helt känd.
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Lennartsson, Alexander, and Martina Blomberg. "Fault Detection in Permanent Magnet Synchronous Motors using Machine Learning." Thesis, Luleå tekniska universitet, Institutionen för system- och rymdteknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-84909.
Повний текст джерелаАнотація:
In the aviation industry, safety and robustness are the number one priorities, which is why they use well-tested systems such as hydraulic actuators. However, drawbacks such as high weight and maintenance have pushed the industry toward newer, electrical, actuators that are more efficient and lighter. Electrical actuators, on the other hand, have some reliability issues. In particular, short circuits in the stator windings of Permanent-Magnet SynchronousMotors (PMSMs), referred to as Inter-Turn Short Faults (ITSFs), are the dominating faults, and is the focus of this thesis. ITSFs are usually challenging to detect and often do not become noticeable until the fault has propagated, and the motor is on the verge of being destroyed. This thesis investigates the possibility of detecting ITSFs in a PMSM, at an early stage when only one turn is shorted. The method is limited to finding the faults using ML algorithms. Both an experiential PMSM and a simulated model of the experimental PMSM, with the ability to induce an ITSF, were used to collect the data. Several Machine Learning (ML) models were developed, and then trained and tested with the collected data. The results show that four of the tested ML models, being: Random Forest, Gaussian SVM, KNN, and the CNN, all achieve an accuracy exceeding 95%, and that the fault can be found at an early stage in a PMSM with three coils connected in parallel in each phase. The results also show that the ML models are able to identify the ITSF when the simulated data is downsampled to the same frequency as the experimental data. We conclude that the ML models, provided in this study, can be used to detect an ITSF in a simulated PMSM, at an early stage when only one turn is shorted, and that there is great potential for them to detect ITSFs in a physical motor as well.
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Oliveira, Ãtila GirÃo de. "Neural classifier aplied in stator winding inter-turn short circuit in three-phase induction motors driven by frequency converter." Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=12285.
Повний текст джерелаАнотація:
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel SuperiorThis dissertation reports applications of artificial neural networks to detect stator winding interturn fault of three phase induction motor drived by frequency inverter. The artificial neural networks, like Simple and Multilayer Perceptron, served as off-line classifiers to short-circuit fault condition or healthy condition. In the training of Multilayer Perceptron, two different algorithms are used: the error back-propagation, which is a classic algorithm, and the extreme learning machine, as a relative new alternative for the classic back-propagation. The new one is more worthwhile because of its implementation easiness and higher speed of computation. The database used on the training and validation of the networks is created from an experimental setting, therefore it is composed by true data. The attributes used as failuresâ indicators are selected from certain frequencies of the spectrum, based on some theories of current signature analysis. In the second instance, the technique of principal components analysis is employed. The results obtained for the designed classifiers are shown, and some considerations are made on their use in real time embedded applications, which is the most important projection for future researches.
Este trabalho deriva da aplicaÃÃo de redes neurais artificiais para a detecÃÃo de curto-circuito entre espiras em motor de induÃÃo trifÃsico, acionado por inversor de frequÃncia. As redes neurais artificiais, do tipo Perceptron Simples e Multicamadas, sÃo usadas para detectar falhas de curto-circuito no bobinamento estatÃrico de motores de induÃÃo trifÃsicos de forma off-line. Para treinamento do Perceptron Multicamadas sÃo usados dois algoritmos distintos: o error back-propagation, que figura como o algoritmo clÃssico na literatura especializada, e o extreme learning machine, que à uma alternativa, relativamente recente, ao algoritmo clÃssico. Este algoritmo à uma opÃÃo atraente para o desenvolvimento rÃpido de classificadores. O banco de dados usado para treinamento e validaÃÃo das redes à obtido a partir de experimentaÃÃo laboratorial, portanto composto de dados reais. Os atributos utilizados para a detecÃÃo da falha sÃo componentes de frequÃncia do espectro harmÃnico da corrente estatÃrica do motor. O critÃrio de escolha destas componentes, a priori, à fundamentado em resultados de investigaÃÃes prÃvias da assinatura de corrente e, em segunda instÃncia, à aplicada a tÃcnica de anÃlise de componentes principais. SÃo apresentados os resultados obtidospelos classificadores projetados, e feitas algumas consideraÃÃes quanto à utilizaÃÃo destes em aplicaÃÃo embarcada e em tempo real, que à a principal projeÃÃo de futuros trabalhos a partir do atual.
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Ge, Yuxue. "Energy Management in More Electric Aircraft through PMSM Fault Diagnosis, Adaptive Load Shedding and Efficient Aircraft Design." Doctoral thesis, Universite Libre de Bruxelles, 2019. https://dipot.ulb.ac.be/dspace/bitstream/2013/287798/5/contratYG.pdf.
Повний текст джерелаАнотація:
More electric aircraft is an electrification scheme of aircraft system with high technical feasibility and good economy. It can reduce the weight of aircraft structure, improve maintenance efficiency and reduce fire hazards. However, the electrification of aircraft system will drastically increase the proportion of electrical equipment, the total power demand and the difficulty of fault diagnosis. This paper uses the energy management method to take up the challenge, with focus on fault diagnosis of permanent-magnet synchronous machines (PMSMs), adaptive load shedding and energy efficient aircraft design. A literature review of the concept evolution from all/more-electric aircraft to energy-optimized aircraft is presented. The main issues of the aircraft electrification process are summarized, and followed by an introduction to the current research and methods. The model of the aircraft electrical system is qualitatively and mathematically recalled, including the generator, the battery, the DC motor, the AC motor, and the electric power converter. The accuracy and computation cost of the aircraft model depends on the complexity of the subsystem models that are involved. Therefore, the level of detail that is necessary for a good precision-versus-simulation-time ratio is discussed by taking the electric system of an industrial level hybrid energy quadcoptor UAV as an example. The analysis shows that the bi-directional instruments, i.e. the electric machine, should be modeled in details while other components can be simplified. PMSMs are a group of on-board electric machines with promising future prospects because of high power density and stability. The model of PMSMs is further developed in this work, especially in the inter-turn and phase-to-phase short-circuit conditions. In case of inter-turn short-circuit fault, a winding-function-based and a fault-current-based model are separately developed. The accuracy of both models are verified and compared through experimental results. The fault-current-based modeling method is applied to the phase-to-phase short-circuit fault and experimentally examined and discussed. General condition monitoring methods require the use of a large number of sensors. A fault detection and isolation method that can have low requirement of sensor is recalled and inherited. The description of the fault phase identification index using this method is relatively imprecise, which is not applicable to the inter-turn short-circuit fault. In this work, the analytical expression of the faulty phase identification index is derived based on the fault models. A method to isolate inter-turn and phase-to-phase short-circuit faults is proposed by a combination of the current- and the voltage-signature residuals. This development expands the application scope of the original fault detection and isolation tool and improves its accuracy. The validity of this fault diagnosis method has been verified by experimental results.Load management is developed to guarantee the normal operation of critical loads by shedding some other loads in case of emergency. Generally, binary decisions are made: either something has gone wrong or everything is fine. However, different types of fault influence the working performance of the load and the entire network in different ways. There are multiple states between totally wrong and pure fine, and the load management decision should be adaptive to each state. In this work, fuzzy logic method is used to degrade the load priority according to the instantaneous working state. Combining it with the fault detection and isolation process, a fault-tolerant adaptive load management is achieved. Finally, this work discusses the aircraft design from the energy management point of view, which consists of the energy efficiency analysis and the multidisciplinary energy efficient design of the integrated aircraft system. The first thermodynamic efficiency has been widely used as a common parameter for depicting the energy utilization, i.e. the ratio of output to input power of the system. However, it ignores the irreversible increase of the entropy and cannot reveal the upper limit of the available work of the system.Based on the second thermodynamic law, this work uses the exergy parameters to analyze the energy utilization of a MEA design scheme. Based on the exergy analysis, an energy-efficient aircraft design method is proposed by optimizing the exergy lost of the whole design. The method could provide a global optimization reference for the integrated aircraft design of a MEA.Doctorat en Sciences de l'ingénieur et technologie
info:eu-repo/semantics/nonPublished
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Singh, Bhanu Pratap. "Real-time detection of stator resistance unbalances in three phase drives." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-286813.
Повний текст джерелаАнотація:
An estimated 30% of the faults in Induction Machine (IM) are related to its stator. These faults are mostly in the form of an Inter-Turn Short Circuit (ITSC) fault i.e., when two winding inside the stator of IM are shorted due to insulation failure. However, ITSC fault can be avoided by detecting them in advance and then scheduling the maintenance of the IM. This thesis studies two methods for detecting this incipient ITSC fault in a three-phase IM and then estimating the stator resistance unbalance due to the ITSC fault. The first method is based on the asymmetry caused in the IM by the ITSC fault. As a result of this asymmetry, the negative sequence components of the stator voltages and the stator currents are generated inside the IM. A healthy IM also have these negative sequence components due to the manufacturing process and the supply voltage unbalances. The characteristics and the compensation methods of these negative sequence components in a healthy IM are discussed. The results show that after compensating the negative sequence components in a healthy machine, they can be used for detecting an ITSC fault and then to calculate the fault quantities as well as the stator resistance unbalances. The second method for detecting an ITSC fault is based on analysing the stator resistance unbalances. A three-phase drive is used to inject DC voltage in the stationary reference frame. The DC current generated by this DC voltage is measured and then by applying Ohm’s law stator phase resistances are calculated. In a healthy IM, the phase resistances are balanced. However, in case of ITSC fault in any of the phases, the phase resistance of that phase deviates from those of the other two phases which can be utilized for detecting ITSC fault.Uppskattningsvis 30% av alla fel i induktionsmaskiner (IM) är kopplad till dess stator. Dessa fel är i huvudsak Inter-Turn Short Circuit (ITSC)-fel, dvs. två lindningar inom IM:ens stator blir kortsluta pga. ett isoleringsfel. Emellertid kan man undvika ITSC-fel genom att detektera dem i förhand och planera underhåll. Det här examensarbetet undersöker två metoder för att detektera ett förestående ITSC-fel i en tre-fas IM. Den första metoden är baserad på asymmetrin i IM:er pga. ITSC-felet. Resultatet av den här asymmetrin är att en negativ sekvens genereras i IM:ens statorspänning och statorström. En oskadad IM kan också visa dessa negativa sekvenser pga. tillverksprocessen och statorspänningsobalanser. Egenskaperna och kompensationsmetoderna för dessa negativa sekvenser i en oskadad IM kommer att diskuteras. Resultaten visar att efter kompenseringen av de negativa sekvenserna i en oskadad IM, kan de användas för att detektera ITSC-fel och efteråt för att beräkna felstorheter och även statormotståndobalanser. Den andra metoden för att detektera ITSC-fel är baserad på en undersökning av statormotståndobalanser. Ett tre-fas-drivsystem används för att injektera likspänning i den stationära referensramen. Likströmmen som följer av denna likspänning mäts och statorfasmotstånden beräkna efteråt med Ohms lag. I en oskadad IM är fasmotstånden balanserade. Däremot, när ett ITSC-fel uppstår i en fas, avviker fasmotståndet i den felaktiga fasen från de andra två fasernas, vilket kan användas för att detektera ITSC-fel.
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MacNamara, Liam. "Development of short turn coal spirals." Thesis, University of Nottingham, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243434.
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Ginzarly, Riham. "Contribution à la modélisation et au pronostic des défaillances d'une machine synchrone à aimants permanents." Thesis, Normandie, 2019. http://www.theses.fr/2019NORMR038/document.
Повний текст джерелаАнотація:
L’objectif de ce travail est d’élaborer un modèle performant/précis de la machine électrique permettant de proposer une technique de pronostic. Dans cette thèse, nous commençons par un état de l’art sur les véhicules électriques hybrides (VHE), les différents types de machines électriques utilisées dans les VHE ainsi que les différents types de défauts pouvant survenir dans ces machines électriques. Nous identifions également les indicateurs de défauts appropriés aux différents défauts considérés. Ensuite, une synthèse de techniques de pronostic pouvant être appliquées est proposée. Le modèle à éléments finis électromagnétiques, thermiques et vibratoires (FEM) de la machine à aimants permanents est présenté. Le modèle est élaboré en fonctionnement normal et défaillant. Les types de défauts considérés sont : démagnétisation, court-circuit et excentricité. Une comparaison entre les deux approches analytique et FEM (méthode numérique) pour la modélisation de machines électromagnétiques est effectuée. Les indicateurs de défauts analysés pour l’extraction les plus pertinents utilisent les différents signaux mesurées suivants : le couple, la température ainsi que les signaux vibratoires en états sains et défectueux. L’approche de pronostic adoptée qui est le modèle de Markov caché (HMM) est développée. L'aspect technique de la méthode est présenté et le module du pronostic est formulé. La méthode de HMM est utilisée pour détecter et localiser les défauts à petites amplitudes. Une stratégie systématique a été développée. Le vieillissement de l’équipement de la machine, en particulier des éléments sensibles comme la bobine de stator et l’aimant permanent, est une question très importante pour le calcul du RUL (Remaining Useful Life). Une stratégie d’estimation pour le calcul RUL est présentée et discutée. La configuration en boucle fermée est très importante. Elle est adoptée par tous les systèmes de véhicules disponibles. Par conséquent, les mêmes étapes mentionnées précédemment s'appliquent également à une configuration en boucle fermée. Un modèle global où l’entrée du FEM de la machine provient de l’onduleur modélisé est élaboréThe core of the work is to build an accurate model of the electrical machine where the prognostic technique is applied. In this thesis we started by a literature review on hybrid electric vehicles (HEV), the different types of electrical machine used in HEV’s and the different types of faults that may occur in those electrical machine. We also identify the useful monitoring parameters that are beneficial for those different types of faults. Then, a survey is presented where all the prognostic techniques that can be applied on this application are enumerated. The electromagnetic, thermal and vibration finite element model (FEM) of the permanent magnet machine is presented. The model is built at healthy operation and when a fault is integrated. The considered types of faults are:demagnetization, turn to turn short circuit and eccentricity. A confrontation between analytical and FEM (numerical method) for electromagnetic machine modeling is illustrated. Fault indicators where useful measured parameters forfault identification are recognized and useful features from the measured parameters are extracted; torque, temperature and vibration signal are elaborated for healthy and faulty states. The strategy of the adopted prognostic approach which is Hidden Markov Model (HMM) is explained. The technical aspect of the method is presented and the prognostic model is formulated. HMM is applied to detect and localize small scale fault small scale faults were where a systematic strategy is developed. The aging of the machine’s equipment,specially the sensitive ones that are the stator coil’s and the permanent magnet, is a very important matter for RUL calculation. An estimation strategy for RUL calculation is presented and discussed for those mentioned machine’s components. Closed loop configuration is very important; it is adopted by all available vehicle systems. Hence, the same previously mentioned steps are applied for a closed loop configuration too. A global model where the input of the machine’s FEM comes from the modeled inverter is built
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Leboeuf, Nicolas. "Contribution à l'étude des machines synchrones à aimants permanents en présence de défauts inter-spires : modélisation, détection de défauts inter-spires." Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0364/document.
Повний текст джерелаАнотація:
Les systèmes électriques embarqués dans l'aéronautique doivent satisfaire à des cahiers des charges de plus en plus exigeants portant sur le poids, les performances et la fiabilité, d'où l'utilisation des Machines Synchrones à Aimants Permanents (MSAP). Vu les contraintes imposées, les prototypes sont parfois assez éloignés d'une MSAP classique. La surveillance en ligne de ces systèmes est alors plus délicate mais représente un enjeu considérable vu l'aspect critique des applications (ailerons d'avion, freinage...) et a pour objectif d'éviter un incident majeur en le détectant puis en basculant sur un système identique redondé. Ce document propose un travail de modélisation de MSAP saine et en présence de défaut inter-spires ayant pour objectif de définir des méthodes de détections de défauts inter-spires en ligne, sans capteurs supplémentaires. Deux approches sont présentées pour modéliser les MSAP en présence de défauts inter-spires et sont comparées à des essais expérimentaux réalisés sur un prototype aéronautique. L'une d'entre elles, reposant sur une approche par Réseaux De Perméances (RDP), permet d'obtenir le meilleur compromis. La partie suivante propose de tester deux approches utilisant un indicateur de défaut basé sur un modèle d'Onduleur-MSAP sain et montre l'intérêt de ce type d'approche comparé à des approches plus classiques. L'ensemble des indicateurs développés est ensuite analysé à l'aide d'un outil utilisant la Reconnaissance de Formes (RDF)Embedded electric systems in aircraft applications have to satisfy to specifications including weight, performances and reliability leading to the use of Permanent Magnet Synchronous Machines (PMSM). Due to these constraints, prototypes are often different from classical PMSM. Online monitoring of these systems is challenging but is still important regarding safety applications (electro mechanical airfoil, braking?). The main aim is to detect major incidents in order to use redundant systems. This work concerns modeling of PMSM under both healthy and inter-turn fault cases in order to defined online fault detection methods without additional sensors. Two approaches are presented and compared to experimental tests concerning PMSM under inter-turn fault conditions. One of them is based on Permeance Network (PN) modelling. It can be considered to be the best compromise. The next part deals with two fault indicators methods based on healthy models of Inverter and PMSM and shows improvements brought by these approaches compared to classical methods. The whole indicators are analyzed using Pattern Recognition (PR)
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Deckoff, Anthony Adlai. "The short-turn as a real time transit operating strategy." Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/41774.
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Tseng, King Jet. "Modelling of gate turn-off thyristors for use in circuit simulations." Thesis, University of Cambridge, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308186.
Повний текст джерелаКниги з теми "Short Circuit turn to turn"
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Stan, Haynes, ed. Turn the other stone. Huntingdon: The Journey, 1997.
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The downward turn: Fourteen short stories. Toronto: Natural Heritage/Natural History, 1994.
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Ten minutes to turn the devil. London: Little, Brown, 1999.
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Dundee, University of, ed. Turn back the cover: An anthology of short stories. Dundee: Nethergate Writers, University of Dundee, 2007.
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Henry, James. The turn of the screw, and other short novels. New York: Signet Classic, 1995.
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Henry, James. The Turn of The Screw and Other Short Novels. New York: Penguin Group USA, Inc., 2008.
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Turn up the heat, I'm thinking!: A humor collection. Morgan Hill, CA: Bookstand Publishing, 2013.
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Henry, James. The turn of the screw. London: J.M. Dent, 1993.
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Henry, James. The turn of the screw. Boston: Bedford Books of St. Martin's Press, 1995.
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Henry, James. The turn of the screw. 2nd ed. Boston: Bedford/St. Martin's, 2004.
Знайти повний текст джерелаЧастини книг з теми "Short Circuit turn to turn"
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Li, Junqing, Dong Wang, Ximei Wang, and Lipeng Zhang. "Fault Features Study of Doubly Fed Induction Generators on the Stator Windings Turn-to-Turn Short Circuit." In Proceedings of the Second International Conference on Mechatronics and Automatic Control, 29–38. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-13707-0_4.
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Kharlamov, Viktor, Pavel Shkodun, and Ignat Shestakov. "Improvement of the Methodology for Improvement of the Turn-to-Turn Short Circuit Detection in the Driving Motor Anchor Winding." In International Scientific Conference Energy Management of Municipal Transportation Facilities and Transport EMMFT 2017, 24–30. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-70987-1_3.
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Young-Jin, Goh, and Kim Kyoung-Min. "Diagnosis of Stator Fault by Inter-Turn Short Circuit for Three-Phase Induction Motor." In Advances in Intelligent Systems and Computing, 609–18. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-13-1165-9_56.
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Rajamany, Gayatridevi, and Sekar Srinivasan. "Neural Network Approach for Inter-turn Short-Circuit Detection in Induction Motor Stator Winding." In Advances in Intelligent Systems and Computing, 537–50. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-7868-2_52.
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Shen, Liuyang, Ziyi Fu, and Sumin Han. "A Review of Fault Features for Inter-turn Short Circuit Fault of PM Motor." In Lecture Notes in Electrical Engineering, 442–51. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-8458-9_47.
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Wang, Hui, Wenping Cao, Cungang Hu, and Siliang Lu. "Detection and Identification of the Inter-Turn Short Circuit Fault in a BLDC Motor." In Lecture Notes in Electrical Engineering, 233–43. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-3171-0_20.
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López Cárdenas, Rodrigo, Luis Pastor Sánchez Fernández, Oleksiy Progrebnyak, and Ángel Alberto Costa Montiel. "Inter-turn Short Circuit and Unbalanced Voltage Pattern Recognition for Three-Phase Induction Motors." In Lecture Notes in Computer Science, 470–78. Berlin, Heidelberg: Springer Berlin Heidelberg, 2008. http://dx.doi.org/10.1007/978-3-540-85920-8_58.
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Li, Bingkun, Yaohui Xu, Caixia Gao, and Nan Zhang. "Diagnosis of Inter-Turn Short-Circuit Fault in Direct-Drive Permanent Magnet Synchronous Motor Using Search Coil." In Lecture Notes in Electrical Engineering, 796–805. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-6203-5_79.
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Krim, Youssef, Saber Krim, and Mohamed Faouzi Mimouni. "Effect of Inter-Turn Short-Circuit Fault on a Wind Energy Conversion System Connected to the Grid." In Deregulated Electricity Market, 111–33. New York: Apple Academic Press, 2022. http://dx.doi.org/10.1201/9781003277231-7.
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Li, Junqing, Haibo Yu, and Lipeng Zhang. "Application of Ensemble Empirical Mode Decomposition on Stator Inter-turn Short-Circuit Fault in Doubly Fed Induction Generators." In Proceedings of the Second International Conference on Mechatronics and Automatic Control, 73–83. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-13707-0_9.
Повний текст джерелаТези доповідей конференцій з теми "Short Circuit turn to turn"
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Arumugam, Puvan, Chris Gerada, Tahar Hamiti, Christopher Hill, and Serhiy Bozhko. "A review on turn-turn short circuit fault management." In 2015 International Conference on Electrical Systems for Aircraft, Railway, Ship Propulsion and Road Vehicles (ESARS). IEEE, 2015. http://dx.doi.org/10.1109/esars.2015.7101528.
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Junqing, Li, Tong Zongyi, and Li Zhonghui. "Study on DFIG stator turn-to-turn short circuit considering control strategy." In 2017 20th International Conference on Electrical Machines and Systems (ICEMS). IEEE, 2017. http://dx.doi.org/10.1109/icems.2017.8056005.
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Jun-qing, Li, Ma Li, and Wang De-yan. "Influence of stator turn-to-turn short-circuit on magnetic field of DFIG." In 2011 International Conference on Electrical Machines and Systems (ICEMS). IEEE, 2011. http://dx.doi.org/10.1109/icems.2011.6073523.
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Hao, Li, Emmanuel Schaeffer, and Tang Tianhao. "A Reconfigure Modelling of Double Stator PMSM after Turn-to-Turn Short Circuit." In 16th International Conference on Informatics in Control, Automation and Robotics. SCITEPRESS - Science and Technology Publications, 2019. http://dx.doi.org/10.5220/0007802106090616.
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Tun, Pyae Phyo, Padmanabhan Sampath Kumar, Ryan Arya Pratama, and Liu Shuyong. "Brushless Synchronous Generator Turn-to-Turn Short Circuit Fault Detection Using Multilayer Neural Network." In 2018 Asian Conference on Energy, Power and Transportation Electrification (ACEPT). IEEE, 2018. http://dx.doi.org/10.1109/acept.2018.8610686.
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Ginzarly, Riham, Ghaleb Hoblos, and Nazih Moubayed. "Localizing Turn to Turn Short Circuit in HEV’s Machine Using Thermal Finite Element Model." In 2018 IEEE International Multidisciplinary Conference on Engineering Technology (IMCET). IEEE, 2018. http://dx.doi.org/10.1109/imcet.2018.8603027.
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Sivakumar, Nadarajan, Bicky Bhangu, S. K. Panda, and Amit Kumar Gupta. "Improved Brushless Synchronous Generator model to study the turn-to-turn short circuit fault." In 2014 IEEE Power & Energy Society General Meeting. IEEE, 2014. http://dx.doi.org/10.1109/pesgm.2014.6939442.
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Lavrenov, Eugeniy O., Zoya S. Temlyakova, and Mikhail E. Vilberger. "Estimate of Turn-to-Turn Short Circuit Influence on an Induction Motor Operation Quality." In 2018 XIV International Scientific-Technical Conference on Actual Problems of Electronics Instrument Engineering (APEIE). IEEE, 2018. http://dx.doi.org/10.1109/apeie.2018.8546117.
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Niu, Fangjian, Xiaoming Yue, Jianhua Zhu, and Hui Chen. "Fault Diagnosis of Rotor Turn-to-turn Short Circuit for Doubly-fed Wind Turbine." In 2022 7th International Conference on Power and Renewable Energy (ICPRE). IEEE, 2022. http://dx.doi.org/10.1109/icpre55555.2022.9960477.
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Zhang, Jingnan, Liqin Wu, and Tianhao Zhang. "Fault diagnosis of stator winding turn to turn short circuit of synchronous rectifier generator." In 2016 IEEE International Conference on Mechatronics and Automation. IEEE, 2016. http://dx.doi.org/10.1109/icma.2016.7558873.
Повний текст джерелаЗвіти організацій з теми "Short Circuit turn to turn"
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Hawtree, J. Preparing printed circuit boards for rapid turn-around time on a plotter. Office of Scientific and Technical Information (OSTI), January 1998. http://dx.doi.org/10.2172/573053.
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Durovic, Mateja, and Franciszek Lech. A Consumer Law Perspective on the Commercialization of Data. Universitätsbibliothek J. C. Senckenberg, Frankfurt am Main, 2021. http://dx.doi.org/10.21248/gups.64577.
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Commercialization of consumers’ personal data in the digital economy poses serious, both conceptual and practical, challenges to the traditional approach of European Union (EU) Consumer Law. This article argues that mass-spread, automated, algorithmic decision-making casts doubt on the foundational paradigm of EU consumer law: consent and autonomy. Moreover, it poses threats of discrimination and under- mining of consumer privacy. It is argued that the recent legislative reaction by the EU Commission, in the form of the ‘New Deal for Consumers’, was a step in the right direction, but fell short due to its continued reliance on consent, autonomy and failure to adequately protect consumers from indirect discrimination. It is posited that a focus on creating a contracting landscape where the consumer may be properly informed in material respects is required, which in turn necessitates blending the approaches of competition, consumer protection and data protection laws.
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Pesis, Edna, Elizabeth J. Mitcham, Susan E. Ebeler, and Amnon Lers. Application of Pre-storage Short Anaerobiosis to Alleviate Superficial Scald and Bitter Pit in Granny Smith Apples. United States Department of Agriculture, January 2013. http://dx.doi.org/10.32747/2013.7593394.bard.
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There is increased demand for high quality fruit produced and marketed with reduced chemical inputs to minimize toxic effects on human health and the environment. Granny Smith (GS) apple quality is reduced by two major physiological disorders, superficial scald and bitter pit (BP). These disorders cause great loss to apple growers worldwide. Superficial scald is commonly controlled by chemical treatments, mainly the antioxidant diphenylamine (DPA) and/or the ethylene action inhibitor, 1-methylcyclopropene (1–MCP). Both chemicals are ineffective in controlling bitter pit incidence. We proposed to investigate the beneficial use of non-chemical, abiotic stress with low O2 (LO2) applied for 10d at 20°C on GS apple fruit. During the project we expanded the treatment to more apple cultivars, Golden Delicious (GD) and Starking Delicious (SD) and another pome fruit, the pear. Apple and pear have similar physiological disorders that develop during cold storage and we examined if the LO2 treatment would also be effective on pear. Application of 0.5% LO2 atmosphere for 10d at 20°C or 500ppb 1-MCP at 20°C prior to cold storage at 0°C, was effective in reducing superficial scald in GS apple. Moreover, LO2 pretreatment was also effective in reducing bitter pit (BP) development in California GS and Israeli GD and SD apples The BP symptoms in GS from California were much more prominent, so the effect of LO2 was more dramatic than the effect on the Israeli cvs. GD and SD, nevertheless the LO2 treatment showed the same trend in all cultivars in reducing BP. The LO2 and 1-MCP -treated fruit exhibited lower levels of ethylene, - farnesene and its oxidation product, 6-methyl-5-hepten-2-one (MHO), as determined by SPME/GC-MS analysis. In addition, LO2 pretreatment applied to California Bartlett or Israeli Spadona pears was effective in reducing superficial scald, senescent scald and internal breakdown after 4 m of cold storage at 0°C. For GS apple, low-temperature storage resulted in oxidative stress and chilling injury, caused by increased production of superoxide anions which in turn led to the generation of other dangerous reactive oxygen species (ROS). Using confocal laser-scanning microscopy and H2O2 measurements of apple peel, we observed ROS accumulation in control fruit, while negligible amounts were found in LO2 and 1-MCP treated fruit. Gene-expression levels of ROS-scavenging enzymes were induced by the various pretreatments: catalase was induced by LO2 treatment, whereas Mn superoxide dismutase was induced by 1-MCP treatment. We assume that LO2 and 1-MCP pretreated fruit remained healthier due to reduced production of ethylene and reactive oxygen substances, such as MHO, during cold storage. The LO2-treated apple exhibited greener peel and firmer fruit after 6 m of cold storage, and the fruit had high crispiness leading to high taste preference. In both pear cultivars, the LO2 treatment led to a reduction in internal breakdown and browning around the seed cavity. We tested the LO2 pre-storage treatment on a semi-commercial scale that would be applicable to a small organic grower by sealing the fruit within the plastic field bins. The treatment was most effective with a continuous flow of nitrogen through the bins; however, a single 6 hour flush of nitrogen was also fairly effective. In addition, we determined that it was very important to have the oxygen levels below 0.5% for approximately 10 days to achieve good scald control, not counting the time required to reduce the oxygen concentration. Our LO2 technology has been proven in this project to be effective in reducing several physiological disorders developed in pome fruit during cold storage. We hope that our non-chemical treatment which is friendly to the environment will be used in the near future for the organic apple and pear industry. The next step should be an analysis of the cost-benefits and commercial feasibility.
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Naess, Lars Otto, Jan Selby, and Gabrielle Daoust. Climate Resilience and Social Assistance in Fragile and Conflict-Affected Settings. Institute of Development Studies (IDS), February 2022. http://dx.doi.org/10.19088/basic.2022.002.
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This paper aims to improve our understanding of the nature, causes, and multiple dimensions of how social assistance may address climate vulnerability and resilience within fragile and conflict-affected settings (FCAS), as part of the inception phase of the Better Assistance in Crises (BASIC) Research programme. Over recent years, social assistance, such as cash transfers and voucher programmes, has been seen as a way of reducing the impacts of climate-related shocks and stressors, and of increasing the resilience of recipient households and communities. It has also been seen as a mechanism for delivering adaptation funding, showing promise in tackling short-term shocks as well as longer-term adaptation to climate change. Yet despite FCAS hosting some of the most vulnerable populations in the world, so far there has been little attention to these settings. We examine the linkages between social assistance and climate resilience in FCAS and in turn, implications for BASIC Research. Specifically, we ask what the evidence is on whether existing approaches to social assistance are appropriate to reducing climate vulnerabilities and building climate resilience in FCAS, and, if not, how they might be reformed. We address this through three sub-questions. First, what are the major conceptual discussions on climate resilience and social assistance, and what is the extent of work in FCAS? This is addressed in section 2.1, based on an extensive literature review. Second, to what extent does the literature on social assistance and climate resilience apply to the particular concerns of FCAS? This is covered in section 2.2, based on a framework informed by work in political economy and political ecology. Third, what are possible future research directions? We conclude with reflections on what BASIC Research may contribute in section 3.
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Borrett, Veronica, Melissa Hanham, Gunnar Jeremias, Jonathan Forman, James Revill, John Borrie, Crister Åstot, et al. Science and Technology for WMD Compliance Monitoring and Investigations. The United Nations Institute for Disarmament Research, December 2020. http://dx.doi.org/10.37559/wmd/20/wmdce11.
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The integration of novel technologies for monitoring and investigating compliance can enhance the effectiveness of regimes related to weapons of mass destruction (WMD). This report looks at the potential role of four novel approaches based on recent technological advances – remote sensing tools; open-source satellite data; open-source trade data; and artificial intelligence (AI) – in monitoring and investigating compliance with WMD treaties. The report consists of short essays from leading experts that introduce particular technologies, discuss their applications in WMD regimes, and consider some of the wider economic and political requirements for their adoption. The growing number of space-based sensors is raising confidence in what open-source satellite systems can observe and record. These systems are being combined with local knowledge and technical expertise through social media platforms, resulting in dramatically improved coverage of the Earth’s surface. These open-source tools can complement and augment existing treaty verification and monitoring capabilities in the nuclear regime. Remote sensing tools, such as uncrewed vehicles, can assist investigators by enabling the remote collection of data and chemical samples. In turn, this data can provide valuable indicators, which, in combination with other data, can inform assessments of compliance with the chemical weapons regime. In addition, remote sensing tools can provide inspectors with real time two- or three-dimensional images of a site prior to entry or at the point of inspection. This can facilitate on-site investigations. In the past, trade data has proven valuable in informing assessments of non-compliance with the biological weapons regime. Today, it is possible to analyse trade data through online, public databases. In combination with other methods, open-source trade data could be used to detect anomalies in the biological weapons regime. AI and the digitization of data create new ways to enhance confidence in compliance with WMD regimes. In the context of the chemical weapons regime, the digitization of the chemical industry as part of a wider shift to Industry 4.0 presents possibilities for streamlining declarations under the Chemical Weapons Convention (CWC) and for facilitating CWC regulatory requirements.
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Quak, Evert-jan. The Link Between Demography and Labour Markets in sub-Saharan Africa. Institute of Development Studies (IDS), January 2020. http://dx.doi.org/10.19088/k4d.2021.011.
Повний текст джерелаАнотація:
This rapid review synthesises the literature from academic, policy, and knowledge institution sources on how demography affects labour markets (e.g. entrants, including youth and women) and labour market outcomes (e.g. capital-per-worker, life-cycle labour supply, human capital investments) in the context of sub-Saharan Africa. One of the key findings is that the fast-growing population in sub-Saharan Africa is likely to affect the ability to get productive jobs and in turn economic growth. This normally happens when workers move from traditional (low productivity agriculture and household businesses) sectors into higher productivity sectors in manufacturing and services. In theory the literature shows that lower dependency ratios (share of the non-working age population) should increase output per capita if labour force participation rates among the working age population remain unchanged. If output per worker stays constant, then a decline in dependency ratio would lead to a rise in income per capita. Macro simulation models for sub-Saharan Africa estimate that capital per worker will remain low due to consistently low savings for at least the next decades, even in the low fertility scenario. Sub-Saharan African countries seem too poor for a quick rise in savings. As such, it is unlikely that a lower dependency ratio will initiate a dramatic increase in labour productivity. The literature notes the gender implications on labour markets. Most women combine unpaid care for children with informal and low productive work in agriculture or family enterprises. Large family sizes reduce their productive labour years significantly, estimated at a reduction of 1.9 years of productive participation per woman for each child, that complicates their move into more productive work (if available). If the transition from high fertility to low fertility is permanent and can be established in a relatively short-term period, there are long-run effects on female labour participation, and the gains in income per capita will be permanent. As such from the literature it is clear that the effect of higher female wages on female labour participation works to a large extent through reductions in fertility.
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Redmond, Paul, Seamus McGuinness, and Klavs Ciprikis. A universal basic income for Ireland: Lessons from the international literature. ESRI, December 2022. http://dx.doi.org/10.26504/rs146.
Повний текст джерелаАнотація:
A universal basic income (UBI) is defined as a universal, unconditional cash payment that is made regularly, is sufficient to live on, is not means tested, carries no work requirements and is paid on an individual basis. This study examines the international evidence on universal basic incomes and identifies key issues for consideration in the design of any UBI pilot for Ireland. Despite the mainstream interest in UBI as a potential policy tool, relatively little is known about the associated consequences of such policies. Even the definition of a UBI appears to be poorly understood and is often misused in the public discourse. Several pilot studies have been recently implemented across different countries. However, some pilot studies depart from the accepted definition of UBI. For example, some are not universal, in that they only target a specific subgroup of the population and/or have eligibility restrictions based on earnings. Others provide a relatively low level of payment, which may fall short of what an individual could reasonably be expected to live on. There are a number of potentially positive impacts associated with a UBI. A universal, unconditional payment could eliminate the stigma associated with welfare receipt. If replacing existing welfare payments, a UBI would also involve lower transaction costs, both on the recipient (in terms of the application procedure) and on Government (in terms of administering the payment). Universal, unconditional payments would also avoid situations where people choose not to work in order to retain means-tested benefits. UBI could give individuals the freedom to turn down or leave insecure, exploitative or low-paid work in pursuit of better or improved work opportunities. In addition, it would mean that persons in informal and often unpaid work, such as childcare and eldercare, which is mostly done by women, receive some compensation for their labour. Empirical results from several pilot studies have found evidence of positive health impacts following the implementation of a UBI. In terms of potential disadvantages, a UBI, by definition, may not target those that are most in need, as a large percentage of recipients will be high-earning individuals. Furthermore, the cost of a UBI is likely to be very expensive, even if other existing benefits (such as unemployment benefits) are no longer required. The net impacts of a UBI on labour supply are unclear, with both positive and negative influences on labour market participation potentially arising as a consequence of a UBI. In this study, we undertake some basic calculations relating to four possible UBI approaches, all of which would involve an unconditional payment to every individual aged over 18 in Ireland.
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Downes, Jane, ed. Chalcolithic and Bronze Age Scotland: ScARF Panel Report. Society for Antiquaries of Scotland, September 2012. http://dx.doi.org/10.9750/scarf.09.2012.184.
Повний текст джерелаАнотація:
The main recommendations of the panel report can be summarised under five key headings: Building the Scottish Bronze Age: Narratives should be developed to account for the regional and chronological trends and diversity within Scotland at this time. A chronology Bronze Age Scotland: ScARF Panel Report iv based upon Scottish as well as external evidence, combining absolute dating (and the statistical modelling thereof) with re-examined typologies based on a variety of sources – material cultural, funerary, settlement, and environmental evidence – is required to construct a robust and up to date framework for advancing research. Bronze Age people: How society was structured and demographic questions need to be imaginatively addressed including the degree of mobility (both short and long-distance communication), hierarchy, and the nature of the ‘family’ and the ‘individual’. A range of data and methodologies need to be employed in answering these questions, including harnessing experimental archaeology systematically to inform archaeologists of the practicalities of daily life, work and craft practices. Environmental evidence and climate impact: The opportunity to study the effects of climatic and environmental change on past society is an important feature of this period, as both palaeoenvironmental and archaeological data can be of suitable chronological and spatial resolution to be compared. Palaeoenvironmental work should be more effectively integrated within Bronze Age research, and inter-disciplinary approaches promoted at all stages of research and project design. This should be a two-way process, with environmental science contributing to interpretation of prehistoric societies, and in turn, the value of archaeological data to broader palaeoenvironmental debates emphasised. Through effective collaboration questions such as the nature of settlement and land-use and how people coped with environmental and climate change can be addressed. Artefacts in Context: The Scottish Chalcolithic and Bronze Age provide good evidence for resource exploitation and the use, manufacture and development of technology, with particularly rich evidence for manufacture. Research into these topics requires the application of innovative approaches in combination. This could include biographical approaches to artefacts or places, ethnographic perspectives, and scientific analysis of artefact composition. In order to achieve this there is a need for data collation, robust and sustainable databases and a review of the categories of data. Wider Worlds: Research into the Scottish Bronze Age has a considerable amount to offer other European pasts, with a rich archaeological data set that includes intact settlement deposits, burials and metalwork of every stage of development that has been the subject of a long history of study. Research should operate over different scales of analysis, tracing connections and developments from the local and regional, to the international context. In this way, Scottish Bronze Age studies can contribute to broader questions relating both to the Bronze Age and to human society in general.
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Cohen, Yuval, Christopher A. Cullis, and Uri Lavi. Molecular Analyses of Soma-clonal Variation in Date Palm and Banana for Early Identification and Control of Off-types Generation. United States Department of Agriculture, October 2010. http://dx.doi.org/10.32747/2010.7592124.bard.
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Date palm (Phoenix dactylifera L.) is the major fruit tree grown in arid areas in the Middle East and North Africa. In the last century, dates were introduced to new regions including the USA. Date palms are traditionally propagated through offshoots. Expansion of modern date palm groves led to the development of Tissue Culture propagation methods that generate a large number of homogenous plants, have no seasonal effect on plant source and provide tools to fight the expansion of date pests and diseases. The disadvantage of this procedure is the occurrence of off-type trees which differ from the original cultivar. In the present project we focused on two of the most common date palm off-types: (1) trees with reduced fruit setting, in which most of the flowers turn into three-carpel parthenocarpic fruits. In a severe form, multi-carpel flowers and fruitlets (with up to six or eight carpels instead of the normal three-carpel flowers) are also formed. (2) dwarf trees, having fewer and shorter leaves, very short trunk and are not bearing fruits at their expected age, compared to the normal trees. Similar off-types occur in other crop species propagated by tissue culture, like banana (mainly dwarf plants) or oil palm (with a common 'Mantled' phenotype with reduced fruit setting and occurrence of supernumerary carpels). Some off-types can only be detected several years after planting in the fields. Therefore, efficient methods for prevention of the generation of off-types, as well as methods for their detection and early removal, are required for date palms, as well as for other tissue culture propagated crops. This research is aimed at the understanding of the mechanisms by which off-types are generated, and developing markers for their early identification. Several molecular and genomic approaches were applied. Using Methylation Sensitive AFLP and bisulfite sequencing, we detected changes in DNA methylation patterns occurring in off-types. We isolated and compared the sequence and expression of candidate genes, genes related to vegetative growth and dwarfism and genes related to flower development. While no sequence variation were detected, changes in gene expression, associated with the severity of the "fruit set" phenotype were detected in two genes - PdDEF (Ortholog of rice SPW1, and AP3 B type MADS box gene), and PdDIF (a defensin gene, highly homologous to the oil palm gene EGAD). We applied transcriptomic analyses, using high throughput sequencing, to identify genes differentially expressed in the "palm heart" (the apical meristem and the region of embryonic leaves) of dwarf vs. normal trees. Among the differentially expressed genes we identified genes related to hormonal biosynthesis, perception and regulation, genes related to cell expansion, and genes related to DNA methylation. Using Representation Difference Analyses, we detected changes in the genomes of off-type trees, mainly chloroplast-derived sequences that were incorporated in the nuclear genome and sequences of transposable elements. Sequences previously identified as differing between normal and off-type trees of oil palms or banana, successfully identified variation among date palm off-types, suggesting that these represent highly labile regions of monocot genomes. The data indicate that the date palm genome, similarly to genomes of other monocot crops as oil palm and banana, is quite unstable when cells pass through a cycle of tissue culture and regeneration. Changes in DNA sequences, translocation of DNA fragments and alteration of methylation patterns occur. Consequently, patterns of gene expression are changed, resulting in abnormal phenotypes. The data can be useful for future development of tools for early identification of off-type as well as for better understanding the phenomenon of somaclonal variation during propagation in vitro.
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Financial Stability Report - Second Semester of 2020. Banco de la República de Colombia, March 2021. http://dx.doi.org/10.32468/rept-estab-fin.sem2.eng-2020.
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The Colombian financial system has not suffered major structural disruptions during these months of deep economic contraction and has continued to carry out its basic functions as usual, thus facilitating the economy's response to extreme conditions. This is the result of the soundness of financial institutions at the beginning of the crisis, which was reflected in high liquidity and capital adequacy indicators as well as in the timely response of various authorities. Banco de la República lowered its policy interest rates 250 points to 1.75%, the lowest level since the creation of the new independent bank in 1991, and provided ample temporary and permanent liquidity in both pesos and foreign currency. The Office of the Financial Superintendent of Colombia, in turn, adopted prudential measures to facilitate changes in the conditions for loans in effect and temporary rules for rating and loan-loss provisions. Finally, the national government expanded the transfers as well as the guaranteed credit programs for the economy. The supply of real credit (i.e. discounting inflation) in the economy is 4% higher today than it was 12 months ago with especially marked growth in the housing (5.6%) and commercial (4.7%) loan portfolios (2.3% in consumer and -0.1% in microloans), but there have been significant changes over time. During the first few months of the quarantine, firms increased their demands for liquidity sharply while consumers reduced theirs. Since then, the growth of credit to firms has tended to slow down, while consumer and housing credit has grown. The financial system has responded satisfactorily to the changes in the respective demands of each group or sector and loans may grow at high rates in 2021 if GDP grows at rates close to 4.6% as the technical staff at the Bank expects; but the forecasts are highly uncertain. After the strict quarantine implemented by authorities in Colombia, the turmoil seen in March and early April, which was evident in the sudden reddening of macroeconomic variables on the risk heatmap in Graph A,[1] and the drop in crude oil and coal prices (note the high volatility registered in market risk for the region on Graph A) the local financial markets stabilized relatively quickly. Banco de la República’s credible and sustained policy response played a decisive role in this stabilization in terms of liquidity provision through a sharp expansion of repo operations (and changes in amounts, terms, counterparties, and eligible instruments), the purchases of public and private debt, and the reduction in bank reserve requirements. In this respect, there is now abundant aggregate liquidity and significant improvements in the liquidity position of investment funds. In this context, the main vulnerability factor for financial stability in the short term is still the high degree of uncertainty surrounding loan quality. First, the future trajectory of the number of people infected and deceased by the virus and the possible need for additional health measures is uncertain. For that reason, there is also uncertainty about the path for economic recovery in the short and medium term. Second, the degree to which the current shock will be reflected in loan quality once the risk materializes in banks’ financial statements is uncertain. For the time being, the credit risk heatmap (Graph B) indicates that non-performing and risky loans have not shown major deterioration, but past experience indicates that periods of sharp economic slowdown eventually tend to coincide with rises in non-performing loans: the calculations included in this report suggest that the impact of the recession on credit quality could be significant in the short term. This is particularly worrying since the profitability of credit establishments has been declining in recent months, and this could affect their ability to provide credit to the real sector of the economy. In order to adopt a forward-looking approach to this vulnerability, this Report presents several stress tests that evaluate the resilience of the liquidity and capital adequacy of credit institutions and investment funds in the event of a hypothetical scenario that seeks to simulate an extreme version of current macroeconomic conditions. The results suggest that even though there could be strong impacts on the credit institutions’ volume of credit and profitability under such scenarios, aggregate indicators of total and core capital adequacy will probably remain at levels that are above the regulatory limits over the horizon of a year. At the same time, the exercises highlight the high capacity of the system's liquidity to face adverse scenarios. In compliance with its constitutional objectives and in coordination with the financial system's security network, Banco de la República will continue to closely monitor the outlook for financial stability at this juncture and will make the decisions that are necessary to ensure the proper functioning of the economy, facilitate the flow of sufficient credit and liquidity resources, and further the smooth operation of the payment systems. Juan José Echavarría Governor