In this dissertation we provide a comprehensive theory for the formation of a moire pattern in a sampled halftone image. We explore techniques for restoring a sampled halftone image with a moire pattern and techniques for preventing a moire pattern when a halftone picture is scanned. Specifically, we study the frequency, phase, and spatial geometry of a moire pattern. We observe and explain the half period phase reversal phenomenon that a moire pattern may exhibit. As a case study, we examine the moire patterns generated by a commercial scanner. We propose three restoration methods, including a notch filtering method, a simulation method, and a relaxation method. We also describe a moire prevention method, the partial inverse Fourier transform method. Finally, we propose a research agenda for further investigation. / Ph. D.

Before Moire patterns are discovered in graphene, graphene was assumed to be found in only the rhombohedral form in nature. After transfer of graphene layer over another substrate was achieved by Andre Geim and Konstantin Novoselov, studies on graphene gained momentum. Following this, moire paterns were observed by scanning tunelling microscopy (STM) and high resolution transmision electron microscopy (HR-TEM). However, stability of these structures are still unknown. In this thesis, for the first time in literature, molecular dynamics of double layer graphene based Moire patterns are investigated as a result of the rotation of two graphene layers with LAMMPS (Large-scale Atomic/Molecular Massively Parallel Simulator) which has a GNU general public license. To model the two graphene layers, hexagonal graphene layers are generated by home writen Octave code. Then, periodicity condition for the Moire patterns are derived in chapter 2 according to rotation of graphene layers around their central axis, perpendicular to the layers. Then these layers with different angles or temperature or size are simulated by LAMMPS. There are 4 kind of molecular dynamics simulations studied according to modeled flakes. These are grouped under the name of &rsquo / Experiment #&rsquo / according to the modeling structure. Experiment-1 simulates double layer hexagonal flakes of graphene at a temperature of 0.1K. Experiment-2 simulates periodic moire patterns under periodic boundary conditions and represents the infinitely large graphene layers at 10K. Experiment 3 is dierent version of the experiment 1 but at higher temperature (10K). Finally, experiment 4 is modeled to show the behaviour of the graphene flake on a growth or attached region. The atoms around the flakes are modeled as a rigid body and constructs some stress on the graphene flakes.

An experimental technique has been presented to probe the mechanical behavior of thin film materials. The method is capable of tensile testing thin films on substrate and free-standing thin film specimens. A mechanical gripper was designed to address the current challenges in gripping thin film specimens. In order to measure the strain field across the gage section, the moire interferometry technique was used and the respective optical setup was designed. A versatile microfabrication process has been developed to fabricate free-standing dog-bone specimens. Aluminum was used as the model material; however, any other metallization material can be integrated in the process. Thin film specimens have been characterized using SEM, AFM, and TEM. A process has been developed to fabrication diffraction gratings on the specimen by FIB milling. Different grating geometries were fabricated and the diffraction efficiency of the gratings was characterized. The structural damage induced by the Ga+ ions during the FIB milling of the specimens was partially characterized using STEM and EDS. In order to extract the strain field information from the moire interferogram data, a numerical postprocessing technique was developed based on continuous wavelet transforms (CWT). The method was applied on simulated uniform and nonuniform strain fields and the wavelet parameters were tuned to achieve the best spatial localization and strain accuracy.

An experimental technique has been presented to probe the mechanical behavior of thin film materials. The method is capable of tensile testing thin films on substrate and free-standing thin film specimens. A mechanical gripper was designed to address the current challenges in gripping thin film specimens. In order to measure the strain field across the gage section, the moire interferometry technique was used and the respective optical setup was designed. A versatile microfabrication process has been developed to fabricate free-standing dog-bone specimens. Aluminum was used as the model material; however, any other metallization material can be integrated in the process. Thin film specimens have been characterized using SEM, AFM, and TEM. A process has been developed to fabrication diffraction gratings on the specimen by FIB milling. Different grating geometries were fabricated and the diffraction efficiency of the gratings was characterized. The structural damage induced by the Ga+ ions during the FIB milling of the specimens was partially characterized using STEM and EDS. In order to extract the strain field information from the moire interferogram data, a numerical postprocessing technique was developed based on continuous wavelet transforms (CWT). The method was applied on simulated uniform and nonuniform strain fields and the wavelet parameters were tuned to achieve the best spatial localization and strain accuracy.

Šiame darbe analizuojamos optinės judesio iliuzijos galimybės ir formos, vykstant dinamiškai žiūrovo ir kūrinio sąveikai. Vienas iš būdų judesio iliuzijai suformuoti – optinės iliuzijos kuriamas realiai neegzistuojantis vaizdas, atsirandantis dėl mūsų regos ir suvokimo specifikos. Judesio iliuzija naudojam optiniame bei kinetiniame mene, animacijoje. Analizuojamas Muaro efektas, tarnaujantis priemone žiūrovo ir meno kūrinio sąveikai skatinti. Aptariami kūriniai, kurių meninei idėjai atskleisti kūrinio ir žiūrovo kontakto metu vienas iš jų turi būti judėjimo būsenoje. Gvildenamas ekonomiškumo animacijoje klausimas: analizuojami pavyzdžiai kuomet judesio iliuzija kuriama minimaliomis priemonėmis, išnaudojant žmogaus aplinkos suvokimo galimybes. Analizuojant Analizuojant optinę iliuziją naudojusių kūrėjų darbus darytina išvada, kad ji, dinamiškoje sąveikoje veikdama pojūčius ir sąmonę, kūriniui suteikia įtaigumo o kūrėjui papildomų galimybių manipuliuoti žiūrovu. Kūrybinė dalis - muaro animacijos principu sukurta instaliacija „Motus Animus“. Jos idėjinis-meninis pagrindas – minčių, idėjų, stereotipų kopijavimas, dalijimasis bei plagijavimas vartotojiškoje industrinėje visuomenėje. / This paper concentrates on analyzing the potential and forms of optical illusion in relation to dynamic interaction between the art work and the viewer. Illusion of motion is an image that is created by optical illusion that does not exist in reality, but is registered in the mind because of our visual and cognitive specifications. Optical illusion of motion is used in optical and kinetic art and animation. This paper analyzes Moire effect that is a measure to encourage interaction between a creation and a viewer. This paper discusses art works that in order to reveal their artistic idea, the art work or viewer must move. Also this paper disputes the economy in animation: the cases are analyzed, when optical illusion of motion is achieved by using minimal means and exhausting the possibilities of man’s cognition. The analysis of the works of arts’ of artists that used optical illusion, the conclusion is made that optical illusion in dynamic interaction affects senses and consciousness and therefore delivers suggestibility to the work of art and more possibilities to manipulate the viewer to the artist. The creative project of thesis is an installation “Motus Animus” created by using Moire animation. The ideological and artistic background constitutes of copying, sharing and plagiarizing thoughts, ideas and stereotypes in consumption industrial society.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.

Made available in DSpace on 2014-12-17T14:20:24Z (GMT). No. of bitstreams: 1 KarlaiIABSA_ate_cap3.pdf: 927989 bytes, checksum: fc6d88444c1be35eda7ebdf11832d9d3 (MD5) Previous issue date: 2005-11-04 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Dans ce travail, nous ?tudions la construction narrative du pass? de la ville de Nova Cruz, dans l?agreste potiguar. Les r?cits soulignent l?existence d?un corpus narratif homog?ne qui fait r?f?rence ? l?occupation du lieu et ? l??vangelisation de ses habitants. Ainsi, les images des saints et des missionaires civilisateurs de l?espace qui domestiquent les manifestations d?un esprit autochtone sauvage, habitants du milieu naturel, sont recurrentes dans la description des personnages du pass?. Observant la continuit? s?mantique des diff?rentes versions de l?histoire de la ville, nous nous proposons d?analyser d?une mani?re conjointe les textes de l?historiographie locale et les t?moignages oraux collect?s. Comme il a ?t? possible de le constater, les chemins de l??crit et de l?oral se croisent en plusieurs occasions, ob?issant ? des logiques locales de repr?sentations du pass?. Ainsi, notre ?tude porte sur des champs communs ? l?Anthropologie, ? l?Histoire e ? la Litt?rature. Les reconstructions narratives du pass? local sont aussi activ?es par des faits plus r?cents, des "marques de la m?moire" comme le march?, le train, la croix et le r?servoir, symboles d?une ?poque d?abondance qui suit l?action civilisatrice des personnages ancestraux / Neste estudo, investigamos a constru??o narrativa do passado da cidade de Nova Cruz, no Agreste Potiguar. Os relatos apontam para um corpus narrativo homog?neo que referencia a ocupa??o do local e a evangeliza??o dos seus moradores. Dessa forma, na descri??o dos personagens do passado s?o recorrentes as imagens dos santos e mission?rios civilizadores do espa?o que domesticam as manifesta??es de um esp?rito aut?ctone selvagem, habitante do lugar natural. Observando a continuidade sem?ntica das diferentes vers?es da hist?ria da cidade, propomos analisar conjuntamente os textos da historiografia local e os testemunhos orais coletados nas entrevistas. Como foi poss?vel constatar, os caminhos do escrito e do oral se cruzam em v?rios momentos, obedecendo a l?gicas locais de representa??es do passado. Assim, ancoramos nosso estudo em campos comuns ? Antropologia, ? Hist?ria e ? Literatura. As reconstru??es narrativas do passado local s?o tamb?m acionadas para os eventos mais recentes, nos marcos da mem?ria , como a feira, o trem, o cruzeiro e o silo, s?mbolos da era da abund?ncia que sucede a a??o civilizadora dos personagens ancestrais

Orientador: Inacio Maria Dal Fabbro / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-13T07:26:08Z (GMT). No. of bitstreams: 1 Lino_AntonioCarlosLoureiro_D.pdf: 9389634 bytes, checksum: bc9ff1785fef02812b4b909de86bd347 (MD5) Previous issue date: 2008 / Resumo: A reconstituição do contorno topográfico com geometria simétrica ou assimétrica é uma necessidade fundamental para a ciência e para o desenvolvimento tecnológico. A aplicação do levantamento da topografia dos objetos é refletida em vários campos da ciência como biologia, ortopedia, próteses e órteses humanas, diagnósticos médicos, predição de resultados cirúrgicos, medicina veterinária, controle de qualidade e inspeção industrial, engenharia reversa, modelagem matemática, mecânica dos sólidos, composites, projetos estruturais, elementos de máquinas, robótica e visão de máquina. Este trabalho devota especial atenção a problemas de Engenharia Agrícola tais como definição dos contornos topográficos de animais e produtos vegetais, projetos de elementos de máquinas agrícolas, arquitetura de plantas, interações maquina-solo e maquina-planta, contato pneu-solo, seleção e classificação de produtos agrícolas, determinação de propriedades mecânicas de solo e vegetais, estudos sobre práticas de preparo do solo projetos de embalagens para produtos agrícolas e outros. Entre os métodos perfilométricos mostrados na literatura as técnicas de moiré são consideradas as mais rápidas, de baixo custo, de fácil aplicação e exeqüíveis. A técnica denominada moiré de projeção com deslocamento de fase, devido aos constantes desenvolvimentos, é a que tem aplicabilidade quando comparada às outras técnicas de moiré do gênero. Este trabalho inclui vários exemplos práticos da sua aplicação em vários problemas em Engenharia Agrícola. Determinação da topografia de objetos simétricos, determinação de injurias mecânicas e modelos com coordenadas 3D, são igualmente apresentados. Aplicação de software" tais como ImageJ, Rising Sun Moiré, SCILAB/SIP, Excell e rotinas são apresentadas e igualmente discutidas. As conclusões mostram a exeqüibilidade do método proposto na ciência da Engenharia Agrícola. / Abstract: Shape definition of bodies exhibiting symmetric, non symmetric or irregular geometry is of fundamental necessity for science and technology developments. Applications of objects shape survey is reflected on several science fields as biology, human prosthesis and orthesis, medical diagnosis, prediction of surgical results, orthopedics, veterinary medicine, industrial quality control, reverse engineering, mathematical modeling, solid mechanics, composites, structural design and inspection, machine elements, static and dynamic problems, machine vision and robotics. This research work devotes special attention to agricultural engineering problems as the shape definition of animal as well as vegetable agricultural products, design of farm machinery elements, plant architecture, plant and soil - machine mechanical interactions, soil - tire contact area determination, products selection and sorting, soil and vegetable mechanical properties determination, soil tillage and agricultural practices studies, product packing design and so forth. Amongst the shape survey methods exhibited by the pertinent literature, the moiré methods are here considered feasible, of low cost, of easy application and speedy. Projection moiré with phase shifting technique has been selected to be considered a developed procedure when compared with remaining moiré methods, presenting also recent developments. This research work includes a variety of practical examples on several agricultural engineering subjects. Shape determination of symmetric bodies, determination of mechanical injuries proportions on agricultural products and three dimensional coordinates model are presented as well. Employed softwares included ImageJ, RisingSun Moiré, SCILAB/SIP, Excell and routines. The conclusions refer to the feasibility of the proposed method to the agricultural engineering science. / Doutorado / Maquinas Agricolas / Doutor em Engenharia Agrícola

Orientadores: Inacio Maria Dal Fabbro, Oscar Antonio Braunbeck / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-03T21:58:19Z (GMT). No. of bitstreams: 1 MazzetiFilho_Vitor_M.pdf: 4024694 bytes, checksum: aceb4c0b582fa6307a29aa2a1f92ca5e (MD5) Previous issue date: 2004 / Resumo: Na Engenharia Agrícola muitos problemas envolvem a detenninação de deformações, movimentos ou posições relativas de elementos de máquinas em regime dinâmico. Ensaios dinâmicos utilizando-se métodos convencionais de instrumentação e análise de sinais para coleta e análise dos dados são particularmente complexos, pois exigem o contato da superficie do corpo analisado e o instrumento apropriado à medição da grandeza em estudo. No caso de peças rotativas, o problema se agrava uma vez que para transmitir os sinais dos sensores é necessário o uso anéis coletores e escovas, o que produz ruído nos sinais. Métodos numéricos por sua vez, possuem o inconveniente de ser pouco didáticos e não apresentar relação visível com o fenômeno fisico em estudo, possibilitando que pequenos erros ou inconsistências nas propriedades dos materiais ou nas condições de contorno, levem a resultados completamente equivocados. Existem métodos óticos que permitem a medição de deformações, movimentos e posições relativas de elementos de máquinas em ensaios dinâmicos, dentre eles, o método de Moiré que constitui-se uma ferramenta científica capaz de determinar deslocamentos de 0,5J.!m. Utilizando-se dos métodos convencionais e numéricos, muitas pesquisas têm sido desenvolvidas com o objetivo de determinar a posição relativa das lâminas de cortadores basais de plantas durante as operações de corte, visando reduzir perdas e contaminação de matéria prima, particularmente no caso colheita mecanizada da cana-de-açúcar. A cana-de-açúcar ocupa as primeiras colocações entre as espécies mais cultivadas no Brasil, maior produtor mundial, tendo seu cultivo intimamente dependente das operações de corte. No corte mecanizado, os mecanismos evoluíram pouco desde o início da década de 1970 e o cortador de discos duplos utilizado no corte basal apresenta um desempenho de varredura insatisfatório, fazendo com que o ajuste da altura de corte seja uma opção entre as perdas ou a contaminação da matéria prima. Pesquisas nessa área estão divididas em uma linha direcionada à quantificação e redução da energia consumida no corte e outra na determinação e controle dos parâmetros dos dispositivos de corte, visando o acompanhamento do perfil do solo a fim de reduzir perdas e contaminação da matéria prima minimizando enormes prejuízos do setor sucroalcooleiro. Tendo em vista a complexidade dos métodos convencionais e numéricos para determinar posições relativas de elementos de máquinas e também a necessidade de se concentrar esforços na pesquisa de mecanismos alternativos que evitem a captação de impurezas durante a operação de corte mecanizado de cana-de-açúcar, o presente trabalho considera as hipóteses de que é possível utilizar as Técnicas de Moiré de Sombra para determinar as posições relativas de um disco giratório flexível ao acompanhar um dado perfil que simule a ação do solo nas operações de corte basal de plantas e também que os discos flexíveis apresentam elevado desempenho de varredura motivo pelo qual podem constituir-se em uma nova e grande opção na pesquisa de dispositivos para o corte basal de plantas. Através de um sistema que utiliza uma fonte de luz comum para iluminação do disco em movimento, retículos ou grades obtidas através de técnicas comercialmente disponíveis e uma câmera fotográfica digital, as imagens de um disco flexível em movimento sobre um perfil que simula a ação do solo foram registradas e processadas em aplicativos computacionais, fornecendo informações relativas às deformações provocadas pelo movimento e ação do perfil. A análise dessas informações indicou viabilidade e elevada precisão da Técnica de Moiré de Sombra para determinar as posições relativas de um disco giratório flexível ao acompanhar um dado perfil que simule a ação do solo nas operações de corte basal de plantas e um excelente desempenho de varredura do perfil pelo disco nas velocidades e inclinações usualmente empregadas no corte mecanizado de cana-de-açúcar / Abstract: Problems involving strain, motion or reIative position of farm machine elements determinations under dynamic conditions is of quite common occurrence. Dynamic tests envolving traditional procedure and signal analysis would require instrument contact with body surface, which, quite frequently, generate complicated situations. Numerical methods as the Finite Element, Boundary Integral and others, are not so didatic and does'nt exihbit a visible relantionship between the physical parameters envolved generating few inconsistencies or errors related to boundary conditions and material mechanical properties bringing unreliable results. Altemative optic methods to measure strain, motion and reIative position are frequently reported, under th generic name of photoelasticity which includes speckle, holograms, the photoelastic particular methods and the Moiré family methods. The Moiré methods termed TM is a strong scientific tool capable of measurements in the order of O,5~m. This reseach work reports a reIative position study of a rubber disc idealized as a sugar cane base cutter. The sugarcane is one of the most cultivated crops in Brazil, considered the major world producer which faces particular harvesting problems. Harvesting operation is straight dependent on stalk cutting. Mechanized sugarcane harvesting involves base cutters which did not experience significant design development during the last three decades. In particular the double disc base cutter does not present good performance in following ground surface. In this sense, the height of stalk cut represents a choice between dirt contamination and non harvested cane or cane losses. The research in this area of study is divided in two main lines, being one directed in reducing the amount of energy expended in the cut operation and the a second one directed in determining and controlling the cutting device operational parameters aiming in following ground profile avoiding cane contamination and material losses as well as improving mills performance. By considering the difficulties in determining machine elements relative positions by traditional and the numerical methods and the necessity in concentrating efforts in searching for alternative devices to avoid dirt contamination and cane losses during cut proeedure, this researeh work eonsider two hypothesis. The first one eonsider feasible to employa Shadow Moiré Teehnique in detennining a flexible dise relative positions during a simulated base eutting operation following the ground profile. The seeond hypothesis eonsiders a flexible dise eutter being inedited and great option in plants base eutting deviee researeh due to its high performanee and eapaeity in following ground profile. The experimental proeedure employs a rotating rubber dise being deformed by a deviee whieh simulates the ground profile and a relatively simple and inexpensive optieal setup including a eommon white light souree to illuminate the rubber dise, gratings obtained by eommereial teehniques and a digital eamera. Pietures of the flexible dise were taken and proeessed in a eomputer by eommereial programs generating information on the dise reiative positions as well as its eapaeity in following ground profile. The analysis of these information indieates a high aeeuraey of the Shadow Moiré Teehniques in determining maehine moving parts relative positions and a high perfonnanee and eapaeity of the flexible dise in following a profile as the ground surfaee by employing the usual meehanized sugareane harvesting operational parameters / Mestrado / Maquinas Agricolas / Mestre em Engenharia Agrícola

The deformation on cylindrical surfaces of holes in tensile loaded laminated composite specimens was measured using new moire interferometry techniques. These new techniques were developed and evaluated using a 7075-T6 aluminum control specimen. Grating replication techniques were developed for replicating high quality diffraction gratings onto the cylindrical surfaces of holes. Replicas of the cylindrical specimen gratings (undeformed and deformed) were fabricated onto circular steel sectors. Narrow angular regions of these sector gratings were directly evaluated in a moire interferometer. This moire interferometry approach eliminated potential sources of error associated with other moire interferometry approaches. Two composite tensile specimens, fabricated from IM7/5250-4 pre-preg with ply layups of [0₄/90₄]_3s and [+30₂/-30₂/90₄]_3s, were examined using the newly developed moire interferometry techniques. Circumferential and thickness direction displacement fringe patterns (each 3 degrees wide) were assembled into 90 degrees wide mosaics around the hole periphery for both composite specimens. Distributions of strain were calculated with high confidence on a sub-ply basis at select angular locations. Measured strain behavior was complex and displayed ply-by-ply trends. Large ply related variations in the circumferential strain were observed at certain angular locations around the periphery of the holes in both composites. Extremely large ply-by-ply variations of the shear strain were also documented in both composites. Peak values of shear strain approached 30 times the applied far-field axial strain. Post-loaded viscoelastic shearing strains were recorded that were associated with the regions of large load-induced shearing strains. Large ply-grouping related variations in the thickness direction strain were observed in the [+30₂/-30₂/90₄]_3s specimen. An important large-scale trend was observed where the thickness direction strain tended to be more tensile near the outside faces of the laminate than near the mid-ply region. The measured strains were compared with the three-dimensional analysis technique known as Spline Variational Elastic Laminate Technology (SVELT), resulting in a very close match and corroborating the usefulness of SVELT. / Ph. D.