Дисертації з теми "Magnetic shields"
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BAVASTRO, DAVIDE. "Modeling and design of magnetic shields for electrical Installations." Doctoral thesis, Politecnico di Torino, 2014. http://hdl.handle.net/11583/2538889.
Повний текст джерелаMANCA, MICHELE. "Active shield for low-frequency magnetic fields." Doctoral thesis, Politecnico di Torino, 2015. http://hdl.handle.net/11583/2596361.
Повний текст джерелаНіколенко, Богдан Миколайович. "Електромагнітні екрани для надвисокочастотних полів". Master's thesis, Київ, 2018. https://ela.kpi.ua/handle/123456789/25889.
Повний текст джерелаRelevance of the topic: Shielding of ultrahigh frequency electromagnetic interference fields is an important task of physical protection and electromagnetic compatibility improvement in radio electronic devices. Research purpose: the defining of materials the best to use in electromagnetic shields for ultrahigh frequency interferences rejecting. Object of research: electromagnetic shields. Subject of research: shielding efficiency with shielding factor estimation. Scientific novelty: scientific novelty lies in improving the efficiency of equipment shielding from electromagnetic ultrahigh frequency interferences. It is doing by constructing the shields as three layers of different types of metals (magnetic and nonmagnetic), when the intermediate layer is magnetic and the boundary layers are nonmagnetic. Furthermore, the three-layer shield greatly increases the shielding factor by raising the mechanism of efficiency by reflection of the electromagnetic wave from layer boundaries. Publications: Ніколенко Б. М. Електромагнітні екрани для надвисокочастотних полів / Комп'ютерне моделювання та оптимізація складних систем (КМОСС-2018): матеріали IV Міжнародної науково-технічної конференції / ДВНЗ "УДХТУ". - Дніпро: Баланс-клуб, 2018. - с. 91 - 93.
Ткаченко, Олександр Олегович. "Магнітне поле високовольтних кабельних ліній при двосторонньому заземленні екранів кабелів". Thesis, Інститут технічних проблем магнетизму Національної академії наук України, 2018. http://repository.kpi.kharkov.ua/handle/KhPI-Press/40754.
Повний текст джерелаThesis for scientific degree of candidate of technical sciences (Ph.D.), specialty 05.09.05 – theoretical electrical engineering. – National Technical University "Kharkiv Polytechnic Institute", Kharkiv, 2019. The thesis is devoted to the advancement of methods of physico-mathematical simulation and calculation of the magnetic field created by the high-voltage three-phase cable lines consisting of single-core cables with two-point bonded cable shields. The current tendency of the development of city electric networks implies an increasingly widespread use of three-phase high-voltage cable lines performed by ingleconductor cables with cross-linked polyethylene insulation. However, the cable line magnetic field can exceed the reference level for the population (0.5 μT for living space and 10 μT for an urban area). Therefore, when designing cable lines it is mandatory to calculate accurately their magnetic field using existing regulation documents and analytical solutions based on known methods. At the same time, in the case of two-point bonding, the cable shields form closed loops in which longitudinal currents are induced. These currents create an additional magnetic field that substantially changes the initial cable line magnetic field, that must be taken into account. The problem of simulation of the magnetic field of the cable line with two-point bonded cable shields can be solved numerically. However, analytical methods are more affordable for cable line designers. Also, these methods produce results with a transparent physical interpretation. However, the analytical methods of solving these problems are insufficiently studied. This is due to the lack of theoretically based methods for determining the complex amplitude of currents in the shields of three-phase cable lines and the methods of magnetic field simulating at any arrangement of phase cables. In the thesis, the features of a three-phase cable line with two-point bonded shields as the source of the magnetic field are investigated. It is shown that correct methods of calculating the magnetic field of cable lines can be created only if the currents in cable shields, which are inductively connected with the currents in cable cores, are determined. The analysis of electromagnetic processes in a three-phase cable line with two-point bonded shields based on the method of complex amplitudes is carried out. A generalized physico-mathematical model of the magnetic field of cable lines is developed. It allows to calculate the electric currents induced in shields of cables and to determine the magnetic field distribution for the arbitrary arrangement of cables. The exact expression for the magnetic field shielding factor for the trefoil cable line with two-point bonded shields is obtained. Using the Clark transformation, a simplistic expression for the magnetic field shielding factor is received for the flat cable line with twopoint bonded shields. Its error is within 5%. The possibility of the magnetic field shielding factor 2-4 times increase by ferromagnetic cores installed on cables is justified theoretically and experimentally. In this case the shielding factor depends on parameters of ferromagnetic cores, parameters of cables and their arrangement. The respective expressions for the shielding factor are obtained for trefoil and flat cable lines. The verification of the proposed physico-mathematical model and analytical expressions is performed by numerical simulation and experimentally. Methodologies of the magnetic field and root-mean-square shield currents calculating for the cable line with two-point bonded cable shields are developed.
Ткаченко, Олександр Олегович. "Магнітне поле високовольтних кабельних ліній при двосторонньому заземленні екранів кабелів". Thesis, Національний технічний університет "Харківський політехнічний інститут", 2019. http://repository.kpi.kharkov.ua/handle/KhPI-Press/40753.
Повний текст джерелаThesis for scientific degree of candidate of technical sciences (Ph.D.), specialty 05.09.05 – theoretical electrical engineering. – National Technical University "Kharkiv Polytechnic Institute", Kharkiv, 2019. The thesis is devoted to the advancement of methods of physico-mathematical simulation and calculation of the magnetic field created by the high-voltage three-phase cable lines consisting of single-core cables with two-point bonded cable shields. The current tendency of the development of city electric networks implies an increasingly widespread use of three-phase high-voltage cable lines performed by ingleconductor cables with cross-linked polyethylene insulation. However, the cable line magnetic field can exceed the reference level for the population (0.5 μT for living space and 10 μT for an urban area). Therefore, when designing cable lines it is mandatory to calculate accurately their magnetic field using existing regulation documents and analytical solutions based on known methods. At the same time, in the case of two-point bonding, the cable shields form closed loops in which longitudinal currents are induced. These currents create an additional magnetic field that substantially changes the initial cable line magnetic field, that must be taken into account. The problem of simulation of the magnetic field of the cable line with two-point bonded cable shields can be solved numerically. However, analytical methods are more affordable for cable line designers. Also, these methods produce results with a transparent physical interpretation. However, the analytical methods of solving these problems are insufficiently studied. This is due to the lack of theoretically based methods for determining the complex amplitude of currents in the shields of three-phase cable lines and the methods of magnetic field simulating at any arrangement of phase cables. In the thesis, the features of a three-phase cable line with two-point bonded shields as the source of the magnetic field are investigated. It is shown that correct methods of calculating the magnetic field of cable lines can be created only if the currents in cable shields, which are inductively connected with the currents in cable cores, are determined. The analysis of electromagnetic processes in a three-phase cable line with two-point bonded shields based on the method of complex amplitudes is carried out. A generalized physico-mathematical model of the magnetic field of cable lines is developed. It allows to calculate the electric currents induced in shields of cables and to determine the magnetic field distribution for the arbitrary arrangement of cables. The exact expression for the magnetic field shielding factor for the trefoil cable line with two-point bonded shields is obtained. Using the Clark transformation, a simplistic expression for the magnetic field shielding factor is received for the flat cable line with twopoint bonded shields. Its error is within 5%. The possibility of the magnetic field shielding factor 2-4 times increase by ferromagnetic cores installed on cables is justified theoretically and experimentally. In this case the shielding factor depends on parameters of ferromagnetic cores, parameters of cables and their arrangement. The respective expressions for the shielding factor are obtained for trefoil and flat cable lines. The verification of the proposed physico-mathematical model and analytical expressions is performed by numerical simulation and experimentally. Methodologies of the magnetic field and root-mean-square shield currents calculating for the cable line with two-point bonded cable shields are developed.
Mattsson, Håkan Johannes. "Magnetic anisotropy and paleomagnetism of precambrian rocks in the Fennoscandian shield /." Luleå, 2001. http://epubl.luth.se/1402-1544/2001/32/index.html.
Повний текст джерелаChoi, Tin Chau. "An ultra-wideband magnetic-electric dipole antenna and a shielded slot antenna." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ38622.pdf.
Повний текст джерелаMohammad, Mostak. "Optimization of Inductive Wireless Charging Systems for Electric Vehicles: Minimizing Magnetic Losses and Limiting Electromagnetic Field Emissions." University of Akron / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron1564756659521461.
Повний текст джерелаLu, Ming. "Synergetic Attenuation of Stray Magnetic Field in Inductive Power Transfer." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/78621.
Повний текст джерелаPh. D.
McGrail, Scott Alan. "Hollow Plume Mitigation of a High-Efficiency Multistage Plasma Thruster." DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/1133.
Повний текст джерелаXavier, Rogério Ferreira. "Desenvolvimento e construção de bobinas de gradiente com blindagem ativa (Active Shielding) com aplicação em imagens por RMN." Universidade de São Paulo, 2000. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-06122013-164129/.
Повний текст джерелаActively shielded coils are designed to improve the performance of a gradient coil set by canceling the magnetic field in the region outside the body of the coil, avoiding degradation of the field in its interior due to eddy currents induced in the electric vicinity. The present work resulted on the construction of a shielded gradient coil set (Gx, Gy e Gz) with cylindrical geometry and axial access, with volume diameter of 1 O cm (imaging FOV) and gradient field intensity of 8.0 Gauss/cm in r=0. The maximum gradient distortion aim was 5% inside that volume, along with an effective cancellation of the field close to the inner metallic parts of the OXFORD 2.0 Tesla 31 cm bore horizontal magnet. Preliminary results were obtained with a prototype, which included only one transverse channel, and a miniature set with the same geometry was specially designed to perform micro imaging experiments using pulsed Electron Paramagnetic Resonance. Coils were designed using the current density technique, which is based on the target field approach and simulated annealing for optimization. The gradient systems described here present also a low inductance necessary to perform fast switching (~0.1 ms). For the analysis of the performance of the gradients we used the method of phase reference, confirming the efficiency of the current density technique used on the design of the gradient sets
Дудич, Іван Федорович, та Ivan Dudych. "Обґрунтування параметрів технологічного процесу наплавлення тонких плоских деталей з використанням енергоощадних джерел і режимів нагрівання". Master's thesis, Тернопільський національний технічний університет імені Івана Пулюя, 2020. http://elartu.tntu.edu.ua/handle/lib/33591.
Повний текст джерелаКваліфікаційна робота магістра присвячена питанням обґрунтування параметрів технологічного процесу наплавлення тонких плоских деталей в тому числі відрізного дискового ножа з використанням енергоощадних джерел і режимів нагрівання. Запропоновано та обґрунтовано застосування теплового та електромагнітного екранів для одночасного наплавлення по всій робочій поверхні, що дозволить досягти економії електроенергії на 0,047 кВт при наплавленні однієї деталі, скорочує час наплавлення на 10 с та підвищує стабільність товщини шару наплавленого металу на 12% в порівнянні із традиційною технологією індукційного наплавлення. Крім того для реалізації технологічного процесу вдосконалено конструкцію автоматичної лінії з врахуванням теплового та електромагнітного екранів. В роботі розглянуті питання з охорони праці та безпеки в надзвичайних ситуаціях. Обгрунтовано техніко-економічну ефективність від застосування запропонованих нововедень.
The master's qualification work is devoted to the optimization of parameters of the technological process of surfacing thin flat parts including the disk knife with the use of energy-saving sources and heating modes. The use of thermal and electromagnetic shields for one-step deposition over the entire working surface was suggested and grounded. This enables to save energy on 0.047 kW per a part, to short the surfacing time on 10 seconds and to increase the stability of the weld metal layer thickness on 12% compared to the traditional induction surfacing technology. In addition, to implement the technological process, the design of the automated line with thermal and electromagnetic screens was improved. The work considers the issues of occupational safety and security in emergency situations. The technical and economic efficiency of the suggested innovations is substantiated.
ВСТУП ...6 1 АНАЛІТИЧНА ЧАСТИНА ...7 1.1 Опис конструкції виробу та умов його роботи ...7 1.2 Аналіз технологій виготовлення відрізних дискових ножів ...9 2 ТЕХНОЛОГІЧНА ЧАСТИНА ...13 2.1 Технічне обґрунтування способу наплавлення ...13 2.2 Опис технологічного процесу виготовлення відрізного дискового ножа...18 3 ДОСЛІДНИЦЬКА ЧАСТИНА ...22 3.1 Дослідження процесу індукційного наплавлення із застосуванням теплового та електромагнітного екранів при форсуючому режимі наплавлення ...22 3.2. Металографічні дослідження наплавленого металу ...25 3.3. Дослідження відносної зносостійкості та товщини наплавлюваного металу ...28 4 КОНСТРУКТОРСЬКА ЧАСТИНА ...32 4.1 Механізована лінія для індукційного наплавлення із застосуванням теплового та електромагнітного екранів ...32 4.2 Принцип роботи автоматичної лінії ...38 4.3 Розрахунок прямозубої передачі обертання поворотних планшайб ...40 4.4 Економічна ефективність індукційного наплавлення ...46 5 ОХОРОНА ПРАЦІ ТА БЕЗПЕКА В НАДЗВИЧАЙНИХ СИТУАЦІЯХ ...50 5.1 Розрахунок захисного заземлюючого пристрою для спроектованого цеху (дільниці) ...50 5.2 Заходи для захисту від ураження електричним струмом ...52 5.3 Вимоги до стійкості функціонування промислового підприємства ...55 ВИСНОВКИ ...57 ПЕРЕЛІК ПОСИЛАНЬ ...58 ДОДАТКИ ...61
Frikha, Amin. "Contribution à l'étude du blindage magnétique basse fréquence de boîtiers dédiés aux véhicules électriques et hybrides." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112395/document.
Повний текст джерелаThe electrification of transport means, in recent years leads to an increase of the use of the power electronics and the power involved in electric or hybrid vehicles (HEV). With the integration of electronic devices in more compact environments, appear problems of the electromagnetic compatibility (EMC) and the electromagnetic field exposure. To reduce the effects of electromagnetic fields, electromagnetic shielding is one of the possible solutions.This thesis focus mainly on the magnetic shielding at low frequency in near field of enclosures containing power electronics. Usually, the enclosures are equipped with openings and slots which results in degraded performance of the magnetic shield. We develop models for predicting the magnetic shielding taking into account the effects of diffusion, openings and slots.These models will allow designers to control the magnetic shielding constraints of embedded electronic devices in vehicles. The ability or capability of numerical methods to solve the problems of the magnetic fields diffusion in thin sheets in the presence and absence of openings is presented. In the case of enclosures with slots of small dimensions's, magnetic moments approaches are developed for the prediction of magnetic shielding effectiveness. Test benches are developed to validate these models. In the general case, so-called “hybrid” approaches combining the analytical and numerical methods are developed and experimentally validated. The developed approaches are also applied in the framework of an industrial application
"Testing And Evaluation Of Magnetic Shields For Use In A Prosthetics Application." Tulane University, 2015.
Знайти повний текст джерелаChin, Mo-chu, and 秦孟祖. "AGIS anti-microbe shield modified magnetite for Hyaluronic Acid purification." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/u9tt83.
Повний текст джерела國立臺灣科技大學
化學工程系
94
Hyaluronic acid ( HA ) can be produced through microbial fermentation by using Group A and C streptococci. Traditionally, it is recovered and purified from the fermentation broth by adding Cetylpyridinium chloride (CPC) to form complex with HA. The complex forming effect between CPC and HA involve the hydrophobic and attractive electrostatic interaction. However, the HA recovered by the CPC complexing method may be contaminated with the fermentation media that lowers its purity. Besides, centrifugation or filtration has to be employed to recover the precipitated complex. Silica coated magnetite can be easily modified with a chemical 3-trimethoxy silyl propyl dimethyl octadecyl ammonium choloride (AGIS) which has very similar structure as CPC to become M-AGIS and employed to purify HA from fermentation broth.. By applying magnetic field of enough strength, M-AGIS can be totally recovered. The adsorption isotherm of HA to M-AGIS at pH 4, 37 0C can be described by Langmuir adsorption model with maximum adsorption capacity Qmax of 7.72 mg/g and dissociation constant Kd of 0.0165. Higher temperature favors the adsorption. HA can be eluted from the adsorbent M-AGIS with about 80 % yield by employing 1 M NaCl. By employing M-AGIS, the recovery and purification of HA directly from HA producing cells suspension has been demonstrated.
Bourlon, Évelise. "Analysis of gravity and magnetic fields in the Canadian Shield using standard and wavelet-based methods = Analyse des champs de gravité et magnétique dans le Bouclier canadien à l'aide de méthodes traditionnelles et basées sur la transformée en ondelettes." Thèse, 2004. http://constellation.uqac.ca/699/1/18040901.pdf.
Повний текст джерела