La construction de nouvelles architectures d'aimant moléculaire basé sur l'approche métal-radical repose sur la conception de nouvelles molécules radicalaires. Dans cette optique, notre stratégie s'est concentrée sur la synthèse de porphyrins incorporant des composés radicaux libres. En effet, les porphyrines sont des composés π conjugués qui devraient favoriser la délocalisation de spin et la transmission des interactions magnétiques sur l'entier macrocycle et de plus sur l'ensemble du composé obtenu. A cause de leur excellente stabilité dans une grande diversité d'environnements chimiques et leur capacité à coordonner avec des métaux de transitions, notre choix s'est porté sur les radicaux nitroxides. Dans cette thèse, une série de porphyrines contenant des tBUNO, nitronyl and imino nitroxide directement liés sur le squelette de la molécule ont été synthétisées. Les macrocycles obtenus ont été caractérisés par UV-Vis, Masse et RPE spectroscopie. De plus, durant ce travail, des intermédiaires réactionnaires intéressant ont été obtenus et caractérisés pour la première fois. Ce fut le cas pour la meso-tetrakis(4-formylphenyl)porphyrin et ses équivalents métallés pa le Cu(II) et le Mn(II). Ainsi que pour quelques précurseurs prometteurs de macrocycle tetrapyrroliques comme 2-(3,4-dicyanophenyl)-4,4,5,5-tetramethylimidazoline-3-oxide-1oxyl, 2-(3,4-dicyanophenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl and 2-(4-benzaldehyde)-4,4,5,5-tetramethylimidazoline-1-oxyl. D'après ce que nous savons, ces composés représentent le premier exemple de porphyrines substituées par des nitronyl et imino nitroxide radical, ayant été caractérisées sans ambiguïté par des méthodes spectroscopiques / The preparation of Molecule-Based Magnets is based on the assembling carriers of magnetic moment. These may be the metal ions only with diamagnetic linkers or the metal ions connected through open-shell organic molecule. The building of novel Molecule-Based Magnets architectures following the metal-radical approach relies on the design of innovative open-shell organic molecular blocks. In this regard, we focus our strategy on the synthesis of porphyrins incorporating free radicals. Indeed, porphyrins compounds are π-conjugated systems which should favor spin delocalization and the transmission of the magnetic interactions on the overall macrocycle and further over the all architecture. Due to their excellent stability in a wide variety of chemical environments, and their abilities to coordinate with transition metal we focus our attention on nitroxide radicals. In this dissertation a series of porpyrin macrocycles were synthesized, bearing tBuNO, nitronyl and imino nitroxide covalently linked to the skeleton. Characterization was done by UV-Vis, Mass and EPR spectroscopy. Moreover during this work some interesting synthetic intermediates were obtained with good yield and characterize for the first time. This was the case for meso-tetrakis(4-formylphenyl)porphyrin and its corresponding metallated derivatives by Cu(II) and Mn(II). Some novel promising tetrapyrrolic macrocycle precursors bearing nitronyl and imino nitroxides free radicals as 2-(3,4- dicyanophenyl)-4,4,5,5-tetramethylimidazoline-3-oxide-1-oxyl, 2-(3,4- dicyanophenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl and 2-(4-benzaldehyde)-4, 4, 5, 5-tetramethylimidazoline-1-oxyl. To the best of our knowledge, these compounds represent the first example of nitronyl and imino nitroxide substituted porphyrin derivatives that have been unambiguously characterized by spectroscopic techniques

The master thesis is focused on a remanent magnetism of electromagnets of DC contactors. In the first part of the thesis deals with the formation of a magnetic field in different kinds of materials, description of their magnetization and sorting. The next part is focused on the principle and history of an electromagnet. Negative effects and remanent induction of the contactor are described in the end of the theoretical part. The second part is a practical part. First, the reaction times were measured on a pair of DC contactors. Using the obtained data, an electronic circuit was designed to minimize the difference in switching times of the given DC contactors.

No description available.

[pt] Instrumentos de varredura magnética em estruturas, componentes e materiais têm sido objeto de pesquisa científica e são potenciais protótipos para uso na indústria, sobretudo em inspeção não destrutiva, para identificar defeitos em estruturas metálicas sujeitas a condições extremas como altas temperaturas, pressão e forte tensão. Essas condições podem levar à falhas dessas estruturas comprometendo sua operação, acarretando prejuízos e possíveis acidentes. Nesse sentido, construímos um instrumento para varredura da resposta magnética em placas de aço com defeitos utilizando dois sistemas de medição. No primeiro sistema utilizamos um equipamento comercial: Gaussímetro da marca F.W. BELL (modelo 9950), com três sensores de efeito Hall perpendiculares entre si. No segundo, um gradiômetro construído no Laboratório de Instrumentação do Departamento de Física da PUC-Rio composto de dois sensores de efeito Hall da marca Melexis (modelo 90215). Para a varredura de ambos os sistemas de medição foram utilizados dois atuadores lineares da marca Zaber (modelo T-LLS260C). Com o instrumento construído foi possível identificar defeitos manufaturados por eletroerosão em placas de aço SAE 1020. O segundo sistema de medição se mostrou mais eficiente em detectar defeitos com diâmetros da ordem de 0,90 mm e 10 μm de profundidade. Também construímos um sistema de filtros em uma placa de circuito impresso para atenuar o ruído presente. A partir da análise de sinal-ruído notou-se que o circuito foi eficaz e permitiu uma melhor identificação dos defeitos. Para reforçar a aplicação desse equipamento na pesquisa científica e na indústria, desenvolvemos uma rotina em MATLAB para estimar a profundidade dos defeitos e obtivemos resultados com erro de 3,54 por cento. / [en] Magnetic scanning instruments in structures, components, and materials have been the object of scientific research and are potential prototypes to be used in the industry, especially in non-destructive inspection to identify defects in metal structures subject to extreme conditions, such as high temperatures, pressure, and high tension. These conditions may lead to the failure of these structures, affecting their operation and resulting in losses and possible accidents. In this sense, we developed an instrument for scanning the magnetic response in defective steel plates using two measurement systems. In the first system, we used commercial equipment: Gaussmeter (F.W.BELL, model 9950), with three Hall-effect sensors perpendicular to each other, and in the second one, a gradiometer, composed of two Hall-effect sensors (Melexis, model 90215), developed at the Instrumentation Laboratory of the Physics Department of the PUC-Rio. For scanning both measurement systems, two linear actuators (Zaber, model T-LLS260C) were used. The instrument allows us to identify defects caused by electrical discharge machining on SAE 1020 steel plates. The second measurement system proved to be more efficient in detecting defects with diameters in the order of 0.90 mm and 10 μm in depth. A filter system was also built on a printed circuit board to attenuate noise. The signal-noise analysis showed that the circuit was effective and made possible a better identification of the defects. To reinforce the application of this instrument in scientific research and industry, a routine in MATLAB was developed to estimate the depth of the defects, resulting in an error of 3.54 per cent.

Artificial magnetic materials (AMMs) are a type of metamaterials which are engineered to exhibit desirable magnetic properties not found in nature. AMMs are realized by embedding electrically small metallic resonators aligned in parallel planes in a host dielectric medium. In the presence of a magnetic field, an electric current is induced on the inclusions leading to the emergence of an enhanced magnetic response inside the medium at the resonance frequency of the inclusions. AMMs with negative permeability are used to develop single negative, or double negative metamaterials. AMMs with enhanced positive permeability are used to provide magneto-dielectric materials at microwave or optical frequencies where the natural magnetic materials fail to work efficiently. Artificial magnetic materials have proliferating applications in microwave and optical frequency region. Such applications include inversely refracting the light beam, invisibility cloaking, ultra miniaturizing and frequency bandwidth enhancing low profile antennas, planar superlensing, super-sensitive sensing, decoupling proximal high profile antennas, and enhancing solar cells efficiency, among others. AMMs have unique enabling features that allow for these important applications. Fundamental limitations on the performance of artificial magnetic materials have been derived. The first limitation which depends on the generic model of permeability functions expresses that the frequency dispersion in an AMM is limited by the desired operational bandwidth. The other constraints are derived based on the geometrical limitations of inclusions. These limitations are calculated based on a circuit model. Therefore, a formulation for permeability and magnetic susceptibility of the media based on a circuit model is developed. The formulation is in terms of a geometrical parameter that represents the geometrical characteristics of the inclusions such as area, perimeter and curvature, and a physical parameter that represents the physical, structural and fabrication characteristics of the medium. The effect of the newly introduced parameters on the effective permeability of the medium and the magnetic loss tangent are studied. In addition, the constraints and relations are used to methodically design artificial magnetic material meeting specific operational requirements. A novel design methodology based on an introduced analytical formulation for artificial magnetic material with desired properties is implemented. The synthesis methodology is performed in an iterative four-step algorithm. In the first step, the feasibility of the design is tested to meet the fundamental constraints. In consecutive steps, the geometrical and physical factors which are attributed to the area and perimeter of the inclusion are synthesized and calculated. An updated range of the inclusion's area and perimeter is obtained through consecutive iterations. Finally, the outcome of the iterative procedure is checked for geometrical realizability. The strategy behind the design methodology is generic and can be applied to any adopted circuit based model for AMMs. Several generic geometries are introduced to realize any combination of geometrically realizable area and perimeter (s,l) pairs. A realizable geometry is referred to a contour that satisfies Dido's inequality. The generic geometries introduced here can be used to fabricate feasible AMMs. The novel generic geometries not only can be used to enhance magnetic properties, but also they can be configured to provide specific permeability with desired dispersion function over a certain frequency bandwidth with a maximum magnetic loss tangent. The proposed generic geometries are parametric contours with uncorrelated perimeter and area function. Geometries are configured by tuning parameters in order to possess specified perimeter and surface area. The produced contour is considered as the inclusion's shape. The inclusions are accordingly termed Rose curve resonators (RCRs), Corrugated rectangular resonators (CRRs) and Sine oval resonators (SORs). Moreover, the detailed characteristics of the RCR are studied. The RCRs are used as complementary resonators in design of the ground plane in a microstrip stop-band filter, and as the substrate in design of a miniaturized patch antenna. The performance of new designs is compared with the counterpart devices, and the advantages are discussed.

Artificial magnetic materials (AMMs) are a type of metamaterials which are engineered to exhibit desirable magnetic properties not found in nature. AMMs are realized by embedding electrically small metallic resonators aligned in parallel planes in a host dielectric medium. In the presence of a magnetic field, an electric current is induced on the inclusions leading to the emergence of an enhanced magnetic response inside the medium at the resonance frequency of the inclusions. AMMs with negative permeability are used to develop single negative, or double negative metamaterials. AMMs with enhanced positive permeability are used to provide magneto-dielectric materials at microwave or optical frequencies where the natural magnetic materials fail to work efficiently. Artificial magnetic materials have proliferating applications in microwave and optical frequency region. Such applications include inversely refracting the light beam, invisibility cloaking, ultra miniaturizing and frequency bandwidth enhancing low profile antennas, planar superlensing, super-sensitive sensing, decoupling proximal high profile antennas, and enhancing solar cells efficiency, among others. AMMs have unique enabling features that allow for these important applications. Fundamental limitations on the performance of artificial magnetic materials have been derived. The first limitation which depends on the generic model of permeability functions expresses that the frequency dispersion in an AMM is limited by the desired operational bandwidth. The other constraints are derived based on the geometrical limitations of inclusions. These limitations are calculated based on a circuit model. Therefore, a formulation for permeability and magnetic susceptibility of the media based on a circuit model is developed. The formulation is in terms of a geometrical parameter that represents the geometrical characteristics of the inclusions such as area, perimeter and curvature, and a physical parameter that represents the physical, structural and fabrication characteristics of the medium. The effect of the newly introduced parameters on the effective permeability of the medium and the magnetic loss tangent are studied. In addition, the constraints and relations are used to methodically design artificial magnetic material meeting specific operational requirements. A novel design methodology based on an introduced analytical formulation for artificial magnetic material with desired properties is implemented. The synthesis methodology is performed in an iterative four-step algorithm. In the first step, the feasibility of the design is tested to meet the fundamental constraints. In consecutive steps, the geometrical and physical factors which are attributed to the area and perimeter of the inclusion are synthesized and calculated. An updated range of the inclusion's area and perimeter is obtained through consecutive iterations. Finally, the outcome of the iterative procedure is checked for geometrical realizability. The strategy behind the design methodology is generic and can be applied to any adopted circuit based model for AMMs. Several generic geometries are introduced to realize any combination of geometrically realizable area and perimeter (s,l) pairs. A realizable geometry is referred to a contour that satisfies Dido's inequality. The generic geometries introduced here can be used to fabricate feasible AMMs. The novel generic geometries not only can be used to enhance magnetic properties, but also they can be configured to provide specific permeability with desired dispersion function over a certain frequency bandwidth with a maximum magnetic loss tangent. The proposed generic geometries are parametric contours with uncorrelated perimeter and area function. Geometries are configured by tuning parameters in order to possess specified perimeter and surface area. The produced contour is considered as the inclusion's shape. The inclusions are accordingly termed Rose curve resonators (RCRs), Corrugated rectangular resonators (CRRs) and Sine oval resonators (SORs). Moreover, the detailed characteristics of the RCR are studied. The RCRs are used as complementary resonators in design of the ground plane in a microstrip stop-band filter, and as the substrate in design of a miniaturized patch antenna. The performance of new designs is compared with the counterpart devices, and the advantages are discussed.

Ce travail de thèse concerne la miniaturisation et l’intégration de composants magnétiques comme les inductances utilisées dans les convertisseurs DC-DC et les circuits haute fréquence. Cette thèse a pour objectifs : - de développer une méthodologie d’étude des inductances à couches magnétiques - de montrer la faisabilité de tels composants utilisant des couches épaisses de ferrite (50 à 500µm). Le contenu de notre document s’articule ainsi autour de trois axes : la simulation, la réalisation et la caractérisation. En simulation, le logiciel HFSS, nous a permis de concevoir, de prédire le comportement du composant et d'étudier l’influence des différents entrefers et épaisseurs du matériau magnétique. La réalisation fait appel aux différentes et nombreuses étapes micro technologiques qui sont décrites en détail. Ces étapes concernent les techniques de dépôt sous vide, les procédés de photolithographie, les techniques de dépôt électrolytique, les techniques de sciage et de collage. Enfin, la caractérisation des inductances réalisées a été effectuée en basses, moyennes et hautes fréquences respectivement au LCR mètre (20Hz à 1MHz), à l’impédance mètre (40Hz à 110MHz) et à l’analyseur vectoriel de réseaux (10MHz à 67GHz) / This thesis concerns the miniaturization and integration of magnetic components such as inductors used in DC-DC converters and high frequency circuits. This thesis aims to: - to develop a methodology for the study of magnetic layers inductors; - to show the feasibility of such components using thick layers of ferrite (50 to 500µm). The content of our document is structured around three axes: simulation, realization and characterization. In simulation, HFSS software allowed us to design, predict the behavior of the component and to study the influence of different air gaps and layers of magnetic material. The realization involves numerous and different micro technology steps which are described in detail. These steps are technical of vacuum deposition, photolithography processes, electroplating deposition techniques, techniques of sawing and sticking. Finally, the characterization of inductors achieved was done in low, medium and high frequencies respectively with a LCR meter (20Hz to 1MHz), an impedance meter (40Hz to 110MHz) and a vector network analyzer (10MHz to 67GHz)

The eciency of electrical machines is of major concern due to their widespread usage and the globally increasing awareness of energy consumption issues. Iron losses have a signicant impact on the total and thus researchers and manufacturers of electrical machines are developing dierent strategies in order to reduce them. The iron losses are highly dependent on the magnetic material that is used and thus it is necessary to identify its relevant characteristics. In this work, the development of a control system for inducing a pure sinusoidal magnetic ux density in the magnetic material is described. This is necessary in order to perform characterisation of the magnetic material. The main diculty is the highly non-linear and hysteretic relationship between the magnetic eld strength and the magnetic ux density. In order to mitigate the eect of the hysteresis, a mathematical inverse model was used in the control system. To nd a suitable model, an extensive study of literature was performed and discussed in this work. The Preisach model and its dynamic extension was chosen as the most suitable approach. A detailed description of both theory and implementation details is provided in this work. Furthermore, the model is validated by comparing simulation against measurement data for two dierent materials. In the last part of this work, the inverse model is combined with a controller to form a feedback control system. Two dierent control schemes are investigated: a simpler PI controller and a more elaborate disturbance observer (DOB) based control scheme. The DOB is used to observe the hysteresis inversion error and the observation is used to correct for the error. The controller's ability to produce a pure sinusoidal magnetic ux density was assessed by simulations with dierent magnetic materials at varying frequencies. / Verkningsgraden for elmotorer ar av okande intresse pa grund av deras omfattande anvandning och vaxande oro for globala energiforbrukningsfragor. Jarnforluster har ett stort inytande i de totala forlusterna och ar darfor ett viktigt omrade for forskare och tillverkare av elektriska motorer. Jarnforlusterna beror till stor del av det magnetiska materialet som anvands i konstruktion av elmotorer och det ar darfor nodvandigt att identiera materialets egenskaper. I det har arbetet beskrivs utvecklingen av ett reglersystem for att inducera en ren sinusformat magnetisk odestathet i ett magnetiskt material. Detta ar nodvandigt for att kunna bestamma det magnetiska materialets egenskaper under kontrollerade forhallanden. Huvudsvarigheten ar det icke-linjara sambandet mellan magnetiska faltstyrkan och odest atheten. Sambandet formar en hysteres och for att eliminera dess inytande anvandes en matematisk invers model. For att hitta en lamplig model genomfordes en literaturstudie och Preisach modellen och dess dynamiska utokning valdes. I detta arbete nns en detaljerad beskrivning av bade teorin bakom modellen och dess implementering. Modellen utvarderades genom att jamfora matvarden med simulationsresultat for olika magnetiska material. I sista delen av detta arbete kombineras inversmodellen med ett reglerssystem for att kunna uppna en sinusformat odestathet i det magnetiska materialet. Tva olika regleralgoritmer utvarderas, en enklare PI-regulator och en regulator som inkluderar en sa kallat "Disturbance Observer" (DOB). DOB:n anvandes for att observera felet som uppstar vid invertering av hysteresen och for att korrigera felet. De bada regulatorernas formaga attaterskapa en ren sinusformat magnetisk odestathet testas genom att genomfora simulationer for olika magnetiska material vid varierande frekvenser.

Submitted by Caroline Falcao (caroline.rfalcao@ufpe.br) on 2017-05-22T17:45:56Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) TESE FINAL Carlos Geraldo-PPGO.pdf: 10438439 bytes, checksum: 846645d0ef9edecba48513889f2c3692 (MD5) / Made available in DSpace on 2017-05-22T17:45:56Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) TESE FINAL Carlos Geraldo-PPGO.pdf: 10438439 bytes, checksum: 846645d0ef9edecba48513889f2c3692 (MD5) Previous issue date: 2014-09-29 / O campo magnético é uma fonte acessível de informação direcional passível de ser utilizada pelos seres vivos para orientação e navegação. Animais como mamíferos, aves, peixes, répteis marinhos, anfíbios, moluscos, insetos e crustáceos são sensíveis ao campo geomagnético. O presente estudo enfocou uma avaliação do efeito do campo magnético sobre peixes e crustáceos marinhos em condições naturais (área costeira) e sobre camarões Litopennaeus vannamei em condições controladas (laboratório). Os experimentos com peixes e crustáceos em condições naturais consistiram de sete a oito pescarias independentes, empregando-se armadilhas tipo covo distribuídos em cinco grupos de três a quatro unidades. Magnetos permanentes de 2000 Gauss em um raio de 2m foram fixados próximos à abertura de seis dos dezesete covos empregados. Ao final de cada pescaria os peixes e crustáceos capturados em cada covo foram identificados e contabilizados. Os níveis de capturas de peixes e crustáceos foram significativamente mais elevados nos covos com magneto. Dezessete espécies de crustáceos estiveram presentes nas capturas com os covos, dentre as quais as duas espécies mais frequentes foram Coryrhynchus riisei e Stenorhynchus seticornis. Trinta e duas espécies de peixes ocorreram nas capturas com os covos, com a espécie Haemulon aurolineatum (Xira branca) apresentando uma frequência de ocorrência uma a duas ordens de magnitude superior as demais espécies capturadas, principalmente nos covos com magneto. Ante este resultado, otólitos e tecidos da linha lateral, mancha ocelar, narina e área abdominal (controle) foram extraídos de cinco indivíduos jovens e de cinco indivíduos adultos de H. aurolineatum para investigar a presença de material magnético nessas estruturas. As amostras foram coletadas de indivíduos recém-capturados, secas em estufa e submetidas a medidas de ressonância ferromagnética (RFM) com uso de um espectrômetro Bruker ESP300E. Os espectros obtidos indicaram presença de material magnético nos otólitos, narinas e mancha ocelar e ausência de material magnético nos tecidos da área abdominal de todos os espécimes analisados. Nas amostras da linha lateral, a presença de material magnético pareceu estar relacionada ao desenvolvimento ontogenético, tendo sido detectado principalmente em espécimes adultos. Os experimentos em condições controladas foram realizados com camarões Litopenaeus vannamei considerando-se sexos e fases do seu ciclo ontogenético (machos e fêmeas adultos; machos e fêmeas juvenis e pós-larvas). Um par de bobinas circulares na configuração de Helmholtz, conectada a uma fonte regulável, foi empregado para a geração de diferentes intensidades (0, 25, 30, 35 e 40 μT) de campo magnético artificial uniforme. Os testes foram realizados de forma acumulativa e não acumulativa. No primeiro caso, um mesmo grupo de 15 camarões foi sequencialmente submetido aos cinco níveis de intensidade de campo magnético, com um intervalo de 24h entre exposições. No segundo caso, empregando- se novos grupos de 15 camarões para cada nível de exposição. Todos os testes foram realizados em triplicata. Os resultados evidenciaram a redução da atividade do L. vannamei quando expostos a campos de 35μT e 40 μT e sua paralisia total a campo de 40μT, assim como a preferência na ocupação do polo sul por fêmeas e machos adultos e juvenis e do polo norte por pós-larvas. / The magnetic field is a handy source of directional information that can be used by living things for orientation and navigation. Animals such as mammals, birds, fishes, marine reptiles, amphibians, molluscs, insects and crustaceans are sensitive to the geomagnetic field. The present study focused on an evaluation of the response of marine fishes and shellfishes subjected to an artificial magnetic field under natural conditions (coastal area) and under controlled conditions (laboratory). The experiments with fishes and crustaceans in natural conditions consisted of seven to eight independent fisheries employing creels traps distributed into five groups of three to four units. Permanent magnets of 2000 Gauss in a 2m radius were tied next to the opening of six of the seventeen creels employees. At the end of each fishery, fish and crustaceans caught in each trap were identified and accounted for. The levels of catches of fish and crustaceans were significantly higher in creels with magnet. Seventeen species of crustaceans were present in the catches with the creels, among which the two species most frequently were Coryrhynchus riisei and Stenorhynchus seticorni. Thirty-two species of fish were present in the catchs with the creels. The frequence of occurrence of the speciie Haemulon aurolineatum (Tomtate grunt) was one to two orders of magnitude higher than the other species caught, mainly in creels with magneto. Given this results, Otoliths and tissues of the lateral line, ocelar spot, nostril and abdomen (control) were extracted from five young individuals and five adult individuals of H. aurolineatum to investigate the presence of magnetic material in these structures. The samples were collected from newly captured individuals, oven-dried and subjected to measures of ferromagnetic resonance (RFM) using a Bruker ESP300E spectrometer. The spectra obtained indicated presence of magnetic material in otoliths, nostrils and ocelar spot and absence of magnetic material in the tissues of the abdominal area of all specimens examined. In the samples of the lateral line, the presence of magnetic material seems to be related to the ontogenetic development, having been detected mainly among adult specimens. The experiments under controlled conditions were performed with the shrimp Litopenaeus vannamei considering different sexes and stages of their ontogenetic cycle (adult males and females; juvenils males and females and post-larvae). A pair of circular coils in Helmholtz configuration, connected to an adjustable power source was used to generate different intensities (0, 25, 30, 35 and 40 μT) of uniform artificial magnetic field. The tests were carried out in accumulative and non accumulative manners. In the first case, a group of 15 shrimps was sequentially exposed to the five levels of magnetic field intensity, with a 24 hours interval between exposures. In the second case, using new groups of 15 shrimps for each level of exposure. All tests were performed in triplicate. The results showed a reduction in activity of L. vannamei when exposed to fields of 35 μT and higher and their total paralysis to levels of 40 μT, as well as the preference in the occupation of the South Pole by females and males juvenils and adults and of the North Pole by post-lavae.

Conventional resistance spot welds are not visible from the outside. Therefore, it is not straightforward to evaluate the joint quality non-destructively. The pulse-echo method of manual ultrasonic is widely used for non-destructive testing. Another option is the passive magnetic flux density testing, which is being developed at Technische Universität Dresden, Germany. The spot weld is magnetized in the normal direction and the residual magnetic flux density is measured on top of the surface of the joint. This method is suitable for spot welds on typical car body steels. Previous investigations show that the magnetic properties of the materials influence the test result. In order to develop this new non-destructive testing method further, it is necessary to know the magnetic properties of the different microstructure regions of a spot weld. This article focuses on methods to measure and evaluate the magnetic properties of these regions, especially of the base material and the weld. Different measuring methods and approaches are presented and compared with each other. Based on the results, recommendations for future measurements for magnetic characterizations are given.