本論文主要在研究多層膜之垂直異向性結構組成及其介面特質，本實驗多層膜選取的材料為鐵磁性的鈷(Co)以及貴重金屬的鉑(Pt)，並利用濺鍍(Sputtering)系統來製作(鈷/鉑)多層膜樣品，最初的實驗為尋找(鈷/鉑)多層膜結構組成最佳垂直易性發生之條件，所以分別變化鐵磁層鈷之厚度、一般金屬層鉑之厚度、(鈷/鉑)雙層層數及緩衝buffer layer層鉑之厚度，並利用震動樣品磁度儀(VSM)及超導量子干涉儀(SQUIDE)分別量測垂直及平行磁場方向之磁化強度M對磁場field H的關係，再由M-H圖進行判別其垂直異向性的程度。 在最初的實驗部分可了解如何得到最佳(鈷/鉑)垂直異向性多層膜之結構，並從中可得不同緩衝層鉑之厚度、(鈷/鉑)雙層層數及雙層內鉑之厚度的矯頑場有一趨勢存在，於第二部分的實驗即利用這些矯頑場之趨勢來製作一系列產生巨磁效應之三層膜結構，其中的鐵磁層由(鈷/鉑)垂直異向性多層膜取代，並對此結構做一系列量測，利用震動樣品磁度儀(VSM)量測其磁化強度對磁場的關係、利用LR700系統及物理低溫量測系統(PPMS)量測其異常Hall effect霍爾效應(EHE)現象和電阻對磁場的關係，再將這一系列的量測結果分析其中被一般金屬層鉑所隔開的上下(鈷/鉑)垂直異向性多層膜之間耦合程度。 / The topic of this thesis is about the property of the interface and structure in the multilayers with perpendicular anisotropy. The materials of this multilayers are ferromagnetic cobalt and platinum. We use sputtering system to fabricate cobalt/platinum multilayer with various thicknesses. The initial experiment is to search for the optimum condition that develop cobalt/platinum multilayer with perpendicular anisotropy. Then, the influenceof the buffer layer of platinum is studied. We use Vibrating sample magnetometer (VSM) and superconducting quantum interference device (SQUID) magnetometer to measure the magnetization vs. magnetic field relation by applied magnetic fields in both out of plane and in plane directions to distinguishe the degree of perpendicular anisotropy from the M-H figures. From the initial experiments we can understand how to get the optimum structure of cobalt/platinum perpendicular anisotrpy multilayer. There is a tendency exists in the coercivity depending on different thicknesses of the ferromagnetic layer cobalt, the normal noble platinum, the number of bilayers of cobalt/platinum, and the buffer layer of platinum. In the second part of this experiment we used the difference of coercivities to fabricate a series of trilayers structures that produce giant magnetoresistance effect. The individual ferromagnetic layer was cobalt/platinum perpendicular anisotropy multilayer. The structures was measured by VSM to study magnetization vs. field relation. A LR700 resistance bridge and a physical properties measurement system (PPMS) were used to measure the Anomalous Hall Effect (AHE) and resistant vs. field relation.

Made available in DSpace on 2014-12-17T14:48:17Z (GMT). No. of bitstreams: 1 GilvanBSJ_DISSERT.pdf: 3763149 bytes, checksum: 74cfc52e8eaadf3e1722a2a37d52aca9 (MD5) Previous issue date: 2014-03-07 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Usually masonry structures has low tension strength, hence the design to flexural efforts can results in high reinforcement ratio, specification of high unit and prism strength, structural members with larger section dimensions and modification in structural arrangement to be possible to use masonry members. The main objective of this study is to evaluate the stiffness, the efforts distribution and the effect of horizontal elements (girders) and vertical elements (counterforts) distribution on the behavior of masonry blocks retaining walls. For this purpose, numerical modeling was performed on typical retaining wall arrangements by varying the amount and placement of horizontal and vertical elements, beyond includes elements simulating the reactions of the soil supporting the foundation of the wall. The numerical modeling also include the macro modeling strategy in which the units, mortar and grout are discretized by a standard volume that represents the masonry elastic behavior. Also, numerical model results were compared with those ones of simplified models usually adopted in bending design of masonry elements. The results show horizontal displacements, principal and shear stresses distribution, and bending moments diagrams. From the analysis it was concluded that quantity and manner of distribution of the girders are both important factors to the panel flexural behavior, the inclusion of the foundation changed significantly the behavior of the wall, especially the horizontal displacements, and has been proposed a new way of considering the flanges section of the counterforts / As estruturas de alvenaria solicitadas por elevados esfor?os de flex?o podem necessitar, dada a baixa resist?ncia ? tra??o, de elevadas taxas de armadura; de maior resist?ncia ? compress?o da alvenaria; de elementos estruturais com maiores dimens?es ou mesmo um rearranjo desses elementos para possibilitar o emprego da alvenaria. O estudo ora apresentado tem por objetivo avaliar a rigidez, a distribui??o de esfor?os e o efeito da distribui??o de cintas e de elementos verticais (contrafortes) no caso de muros de arrimo de alvenaria estrutural de blocos. Para tanto, foram realizadas modelagens num?ricas de arranjos t?picos de muro, variando a quantidade e o posicionamento de cintas horizontais, o espa?amento entre os contrafortes, al?m de incluir elementos simulando as rea??es do solo de apoio na funda??o do muro. A modelagem num?rica realizada empregou a estrat?gia de macromodelagem em que os blocos, a argamassa e o graute s?o discretizados pelo volume padr?o representativo do comportamento el?stico da alvenaria. Alternativamente, os resultados do modelo num?rico foram comparados com os de modelos simplificados comumente adotados nos projetos desse tipo de elemento estrutural. A an?lise dos resultados consistiu na verifica??o dos deslocamentos transversais, na distribui??o das tens?es principais (para balizar um futuro modelo de bielas e tirantes e os modos de ruptura), na distribui??o das tens?es de cisalhamento, e na obten??o de diagramas de momento fletor. A partir das an?lises foi poss?vel concluir que n?o apenas a quantidade, mas tamb?m a forma de distribui??o das cintas ? um fator relevante para a distribui??o dos esfor?os no painel fletido (pano de alvenaria), a inclus?o dos elementos de funda??o alterou significativamente o comportamento do muro, principalmente os deslocamentos transversais, al?m de ter sido proposta uma nova forma de considera??o de flanges na se??o resistente do contraforte

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In this work the behavior of the magnetoimpedance (MI) in ferromagnetic multilayered (Ni81Fe19/Cu) produced by magnetron sputtering was studied. In all measurements, the probe current was applied perpendicularly to the film surface. The MI measurements were performed in the frequency range 100kHz - 1.8GHz with an HP-4396B impedance analyzer and a specially designed sample holder. Magnetoimpedance ratios of 150% were obtained in some of the studied samples. / Neste trabalho foi estudado o comportamento da magnetoimpedância (MI) em amostras ferromagnéticas (Ni81Fe19) estruturadas em camadas intercaladas com metal normal (Cu) produzidas por magnetron sputtering com a corrente de sonda sendo aplicada perpendicularmente ao plano do filme. A faixa de freqüência usada neste trabalho foi de 100kHz a 1.8GHz num analisador de impedância modelo HP-4396B. Deste modo conseguiuse variações percentuais na MI da ordem de 150%.

Magnetic materials have many applications in technology. The magnetic properties of materials are therefore important to catalogue for future use. In this project, the magnetic properties of thin films of permalloy are investigated. Specifically, the goal is to find the perpendicular magnetic anisotropy energy (PMAE) of thin film geometries of permalloy of varying film thickness. The PMAE is computed with powerful parallel computers using density functional theory (DFT) as implemented in the open-source DFT package OpenMX. The project consists of two parts: Computations on the bulk system and computations on six thin film systems of varying thickness. The thin films are periodic in the basal plane (the permalloy has a tetragonal crystal structure). The easy axis of magnetization was found to be along the c-axis of the tetragonal structure, both for bulk and thin film geometries. For the thin film geometries, this corresponds to an out-of-plane easy axis. The PMAE of the thinnest thin film geometries (4-5 atomic layers) were several times greater than that of the bulk system. Thin films with one more layer of Fe than Ni have especially great PMAE. When comparing the results to another study, the magnetocrystalline anisotropy as computed in this project turned out to be more than two orders of magnitude greater than in the previous study. It is hypothesised that this is because of the differing crystal structure of permalloy used in the study.

<p>This dissertation is the first architectural history devoted to Beverley Minster, a large and ambitious Gothic church located in the East Riding of Yorkshire. Beverley is one of the most important medieval buildings in England, but it has been almost entirely ignored in the literature. The church is composed of three parts: choir and transepts (c. 1225-1260), nave (c. 1308-c. 1370), and west façade (c. 1380-1420). </p><p>The thesis begins with a description of the destroyed buildings that occupied the site during the Saxon and Romanesque periods. The remainder of the dissertation focuses on the work completed at the Minster during the fourteenth century, in the so-called Decorated style. First, the nave is analyzed and its construction is assigned to six campaigns between the years c. 1308-c. 1370. Much discussion is devoted to the "historicism" of the nave's conservative design, which is a subtly modernized version of the east end that preceded it. Contemporary documents also permit discussion of the financial contributions of the laity, canons, and municipal leaders who paid for the nave to be built. </p><p>Finally, a detailed analysis is offered for the furnishings made at Beverley between 1292 and c. 1340: the reredos (high altar screen), sedilia (seating for priests), and the destroyed shrine which once contained the relics of St. John of Beverley. Like the nave, they are all neglected masterpieces of the Decorated style.</p> / Dissertation

Este trabalho apresenta um estudo teórico e experimental a respeito da solicitação de compressão normal às fibras da madeira, para a qual não é previsto ensaio para caracterização, atualmente, na NBR-6230 (Ensaios físicos e mecânicos de madeiras). Foram abordados aspectos referentes à geometria do corpo-de-prova, velocidade de aplicação de carga, direção do carregamento em relação aos anéis de crescimento e condições de umidade. Com base nos resultados obtidos, é proposto método de ensaio para caracterização da madeira solicitada por compressão normal às fibras. / This work presents an experimental study about compression perpendicular to the grain in wood, for which characterization test is not indicated by NBR-6230 (Physical and mechanical test in wood). Several points were discussed: specimen geometry, speed of testing, direction of loading referred to the growth rings and moisture conditions. Based on the experimental data, a testing procedure is proposed in order to be employed in wood characterization in compression perpendicular to the grain.

Este trabalho apresenta um estudo teórico e experimental a respeito da solicitação de compressão normal às fibras da madeira, para a qual não é previsto ensaio para caracterização, atualmente, na NBR-6230 (Ensaios físicos e mecânicos de madeiras). Foram abordados aspectos referentes à geometria do corpo-de-prova, velocidade de aplicação de carga, direção do carregamento em relação aos anéis de crescimento e condições de umidade. Com base nos resultados obtidos, é proposto método de ensaio para caracterização da madeira solicitada por compressão normal às fibras. / This work presents an experimental study about compression perpendicular to the grain in wood, for which characterization test is not indicated by NBR-6230 (Physical and mechanical test in wood). Several points were discussed: specimen geometry, speed of testing, direction of loading referred to the growth rings and moisture conditions. Based on the experimental data, a testing procedure is proposed in order to be employed in wood characterization in compression perpendicular to the grain.

När Eurokod 5, standarden för dimensionering av träkonstruktioner, infördes i Sverige sågjordes det även en sänkning av hållfasthetsvärden för trä vid tryck vinkelrätt fibrerna.Tidigare kapacitet på 8 MPa för limträklass L40 var nu för högt, och den av SverigesTekniska Forskningsinstitut (SP) reviderade CE L40c fick en kapacitet på 2,7 MPa. Ettproblem i och med detta blev att byggnader som är konstruerade och uppförda enligtBoverkets föreskrifter inte längre kan utformas på samma sätt sedan Eurokodernasinförande. Syftet med arbetet blev därför att:• Ta reda på varför sänkningen skedde• Ta fram några räkneexempel på hur man kan åtgärda för låg kapacitet vid tryckvinkelrätt fibrernaLitteraturstudien som ligger till grund för arbetet visar på att sänkningen skedde på grund avatt Eurokodernas provmetod för bestämning av hållfastheten skiljer sig från den metod somBoverket använt. Den stora skillnaden ligger i att Eurokoderna inte utnyttjar lastspridning iträ, där lasten kan spridas från en träfiber till en annan intilliggande och på så vis öka denfaktiska kapaciteten. Det kan också nämnas att själva dimensioneringsprocessen inte har likastor betydelse som hållfasthetsklassningen.De beräkningar som gjordes i enlighet med arbetets andra syfte visar lämpligaförstärkningsåtgärder vid upplaget. De tre förstärkningsåtgärder som har undersökts är:• Stålplåt som läggs mellan pelare och balk för att på så vis utöka upplagslängd ochdärmed sprida upplagstrycket• Stålskruvar som skruvas in vid upplaget, tvärs fibrerna i balken• Trästavar som limmas in vid upplaget, tvärs fibrerna i balkenAlla beräkningar utfördes med 100 kN last, balktvärsnitt på 215x630 mm, pelartvärsnitt på215x150 mm och upplagslängd 150 mm.• Då stålplåtens bredd var 215 mm och med stålkvalitet s235 erhölls enligt beräkningaren plåttjocklek på15 mm och en plåtlängd på 270 mm för att klara avdimensionerande last.• För 6 st stålskruvar M12 4.6 och penetrationsdjup 400 mm erhölls enligt beräkningaren ny karakteristisk kapacitet på 5,6 MPa.• För 6 st trästavar av björk, 19 mm diameter och penetrationsdjup 400 mm erhöllsenligt beräkningar en ny karakteristisk kapacitet på 5,07 MPa. / When Eurocode 5, design rules for timber structures, was introduced in Sweden there wasalso a reduction in strength values for structural timber, and especially when it comes tocompression perpendicular to the grain. Earlier on, before Eurocode 5, the capacity ofScandinavian glulam L40 was 8 MPa which now was to be revised by the Technical ResearchInstitute of Sweden (SP). The new value was set to 2.7 MPa and the new revised glulam wasnamed CE L40c. A problem now arose, namely so that existing structures (which aredesigned after the old Swedish standard BKR) no longer can be designed in the same way.The purpose of this thesis was to:• Find out why the reduction in capacity for compression perpendicular to the grainoccurred• Make a few examples through calculations on how to fix this problemThe studies of literature which this thesis is based upon indicates that the reduction incapacity was due to the very nature of how the Eurocodes determines the strength classes,and how it is different from BKR. The big difference is that in the Eurocodes there is noutilization of the physical phenomenon where the loaded wood fibres distributes the load to anearby unloaded fibre. This phenomenon greatly increases the capacity at compressionperpendicular to the grain. It should be mentioned that this work also indicates that thedesign process does not have the same impact on the design of structures as the grading ofstrength classes has.According to the second purpose of this thesis, a set of calculations were made whichindicates appropriate methods of reinforcement of a wooden beam. The three methods are:• A steel plate which is placed between a column and a beam to increase the supportlength and therefore spread the support stress over a larger area of the beam• Steel screws which are screwed into the beam at the support, perpendicular to thegrain• Wooden rods which are glued in place inside the beam at the support, perpendicularto the grainAll calculations were made with a load of 100 kN, cross section of the beam is 215x630 mm,cross section of the column is 215x150 mm and support length is 150 mm.• When the width of the steel plate is 215 mm and steel grade s235 is used, the steelplate dimensions required are, according to calculations, thickness of 15 mm andlength of 270 mm.• With 6 steel screws, M12 4.6 and a penetration depth of 400 mm, a new characteristiccapacity of 5.6 MPa was obtained.• With 6 wooden rods made out of birch, 19 mm diameter and a penetration depth of400 mm, a new characteristic capacity of 5.07 MPa was obtained.

The compressive strength perpendicular to grain of cross laminated timber (CLT) was studied experimentally. The problem was also theoretically analyzed and a finite element model was created and solved using a commercial finite element software package. The experiments were carried out with three layer CLT specimens of dimensions 200x200x120 mm and 300x300x120 mm. In some of the experiments a contact free deformation measurement system was used to analyze the strain field during loading. Different ways to apply the load were used: over the whole surface of the specimens and by a 50 mm wide steel bar. The position of the steel bar in relation to the specimen edge and its orientation relative the surface grain direction was varied. It was found that the compression strength of the cross laminated timber depended on the way in which the load was applied. The compression strength perpendicular to grain was found vary from 2.9 N/mm2 for specimens loaded by a line load at the edge of the specimen and parallel to the surface grain direction to 5.8 N/mm2 for specimens loaded by a line load at the specimen centre and perpendicular to the surface fiber direction. / Tryckhållfastheten vinkelrät fiberriktningen i korslimmade massivträskivor (CLT) bestämdes experimentellt. Även teoretiska studier genomfördes med hjälp av ett kommersiellt finita elementprogram. Provningarna genomfördes på treskiktsskivor med måtten 200x200x120 mm samt 300x300x120 mm. I vissa av försöken användes dessutom ett mätsystem för beröringsfri deformationsmätning för att bestämma töjningsfälten. Olika sätt att belasta provbitarna undersöktes: genom att belasta hela provytan eller genom att belasta provet med en 50 mm bred stålstav. Stålstavens läge i förhållande till provbitens kant och dess orientering i förhållande till ytskiktets fiberriktning varierades. De experimentella resultaten visade att hållfastheten beror på hur provbitarna belastas. Tryckhållfastheten varierade mellan 2.9 N/mm2 för fallet med en linjelast vid provbitens kant och orienterad parallellt med ytskiktets fiberriktning och 5.8 N/mm2 för fallet med en linjelast mitt på provbiten och orienterad vinkelrät mot ytskiktets fiberriktning.

<p> </p><p>The compressive strength perpendicular to grain of cross laminated timber (CLT) was studied experimentally. The problem was also theoretically analyzed and a finite element model was created and solved using a commercial finite element software package. The experiments were carried out with three layer CLT specimens of dimensions 200x200x120 mm and 300x300x120 mm. In some of the experiments a contact free deformation measurement system was used to analyze the strain field during loading. Different ways to apply the load were used: over the whole surface of the specimens and by a 50 mm wide steel bar. The position of the steel bar in relation to the specimen edge and its orientation relative the surface grain direction was varied. It was found that the compression strength of the cross laminated timber depended on the way in which the load was applied. The compression strength perpendicular to grain was found vary from 2.9 N/mm² for specimens loaded by a line load at the edge of the specimen and parallel to the surface grain direction to 5.8 N/mm² for specimens loaded by a line load at the specimen centre and perpendicular to the surface fiber direction.</p><p><strong> </strong></p> / <p> </p><p>Tryckhållfastheten vinkelrät fiberriktningen i korslimmade massivträskivor (CLT) bestämdes experimentellt. Även teoretiska studier genomfördes med hjälp av ett kommersiellt finita elementprogram. Provningarna genomfördes på treskiktsskivor med måtten 200x200x120 mm samt 300x300x120 mm. I vissa av försöken användes dessutom ett mätsystem för beröringsfri deformationsmätning för att bestämma töjningsfälten. Olika sätt att belasta provbitarna undersöktes: genom att belasta hela provytan eller genom att belasta provet med en 50 mm bred stålstav. Stålstavens läge i förhållande till provbitens kant och dess orientering i förhållande till ytskiktets fiberriktning varierades. De experimentella resultaten visade att hållfastheten beror på hur provbitarna belastas. Tryckhållfastheten varierade mellan 2.9 N/mm² för fallet med en linjelast vid provbitens kant och orienterad parallellt med ytskiktets fiberriktning och 5.8 N/mm² för fallet med en linjelast mitt på provbiten och orienterad vinkelrät mot ytskiktets fiberriktning.</p><p><strong> </strong></p>