In this master thesis, the magnetic properties of SiFe laminations after cutting and welding are studied. The permeability and the iron loss density are investigated since they are critical characteristics for the performance of electrical machines. The magnetic measurements are conducted on an Epstein frame for sinusoidal variations of the magnetic ux density at frequencies of 50, 100 and 200 Hz, according to IEC 404-2. Mechanical cutting with guillotine and cutting by means of ber and CO2 laser are performed. The inuence of the ber laser settings is also investigated. Especially the assisting gas pressure and the power, speed and frequency of the laser beam are considered. In order to increase the cutting e ect, the specimens include Epstein strips with 1, 2 and 3 additional cutting edges along their length. It is found that mechanical cutting degrades the magnetic properties of the material less than laser cutting. For 1.8% Si laminations, mechanical cutting causes up to 35% higher iron loss density and 63% lower permeability, compared to standard Epstein strips (30 mm wide). The corresponding degradation for laser cut laminations is 65% iron loss density increase and 65% permeability drop. Material of lower thickness but with the same Si-content shows lower magnetic deterioration. Additionally, laser cutting with high-power/high-speed characteristics leads to the best magnetic characteristics among 15 laser settings. High speed settings have positive impact on productivity, since the cutting time decreases. The inuence of welding is investigated by means of Epstein measurements. The test specimens include strips with 1, 3, 5 and 10 welding points. Experiments show an iron loss increase up to 50% with a corresponding 62% reduction in the permeability. A model that incorporates the cutting e ect is developed and implemented in a FEMbased motor design software. Simulations are made for a reference induction motor. The results indicate a 30% increase in the iron losses compared to a model that does not consider the cutting e ect. In case of laser cut core laminations, this increase reaches 50%. The degradation prole considers also the deteriorated magnetizing properties. This leads to increased nominal current up to 1.7% for mechanically cut laminations and 3.4% for laser cut la / I detta examensarbete studeras hur de magnetiska egenskaperna hos SiFe-plat paverkas av skarning och svetsning. Permeabilitet och jarnforlustdensitet undersoks eftersom de ar kritiska variabler for elektriska maskiners prestanda. De magnetiska matningarna genomfordes pa en Epstein ram med en odesfrekvens pa 50, 100 och 200 Hz, enligt IEC 404-2. E ekterna av mekanisk skarning med giljotin samt skarning med ber- och CO2-laser studerades. Inverkan av olika berlaserinstallningar undersoktes ocksa genom att variera gastrycket, skarhastigheten samt frekvensen och e ekten av laserstralen. For att oka skare ekten inkluderades Epsteinremsor med ytterligare 1, 2 och 3 langsgaende skarsnitt. Det visas att mekanisk skarning har en mindre paverkan pa de magnetiska egenskaperna hos materialet an vad laserskarning har. Matningar pa plat med 1.8% Si visar att da prov med tre extra langsgaende giljotinklipp anvands kan permeabiliteten reduceras med upp till 63% och jarnforlusterna kan oka med upp till 35%. Motsvarande resultat for laserskurna platar visar en permeabilitetsreduktion pa upp till 65% och en jarnforlustokning pa upp till 65%. Ur studien av de tva studerade skarprocesserna framkommer aven att tunnare plat paverkas mindre negativt an tjockare plat. Ett antal olika installningar har provats for att utreda hur olika parametrar paverkar e ekterna av laserskarning. Studien indikerar att skarning med hog e ekt och hog hastighet ger den minsta paverkan pa materialets magnetiska egenskaper. Vilket aven har en positiv inverkan pa produktiviteten vid laserskarning. Epsteinprover har aven utforts for att undersoka vilka e ekter som introduceras da SiFe-plat svetsas. Provstyckena bestod av remsor med en, tre, fem och 10 svetspunkter. Experimenten visar en jarnforlustokning med upp till 50% samt en permeabilitetsreduktion upp till 62% da platarna svetsats samman tva och tva. En modell for att studera e ekterna av de forandrade materialegenskaperna vid skarning pa en induktionsmotor utvecklas och implementeras i en FEM-baserad mjukvara. Resultaten tyder pa en jarnforlustokning med 30% da skare ekten orsakad av giljotin beaktas. Vid simulering av laserskuren plat kan denna okning vara sa stor som 50%. Det framkommer aven att laserskarningen kan reducera e ektfaktorn sa mycket som 2.6%.

A combinação de célula eletroquímica (EC) com a entrada do equipamento de eletroforese capilar (CE), apesar de recente, tem permitido realizar determinação de ânions radicais; pré-concentração eletroquímica de metais pesados, seguida de redissolução, separação e detecção; bem como monitorar produtos carregados formados por oxidação eletrocatalítica de espécies neutras, como álcoois primários e glicerol. Empregando o sistema EC-CE-C4D desenvolvido pelo grupo, a determinação simultânea de cátions, ânions (no contra fluxo) e espécies neutras (detectadas após derivatização eletroquímica) foi demonstrada pela primeira vez, tendo o antisséptico bucal (Listerine® Tartar Control) como amostra real. Embora constante e reprodutível, a conversão dos álcoois primários nos respectivos carboxilatos apresentou rendimento relativamente baixo, ~16%, nas condições anteriormente adotadas, 1,6 V vs. Ag/AgClKCl 3M empregando eletrodo de platina em meio ácido (HNO3 5 mmol L-1 / HCl 1 mmol L-1). Dessa maneira, avaliou-se a oxidação de álcoois primários de cadeia normal (C2 − C5) sobre diferentes materiais de eletrodo (ouro e platina) em diferentes meios (ácido, neutro e alcalino). Os carboxilatos gerados foram monitorados injetando uma alíquota da amostra derivatizada no capilar (50 µm d.i., 45 cm de comprimento e 20 cm efetivo) aplicando 5 kPa durante 5 s, e durante as separações, 30 kV foi aplicado entre as extremidades do capilar preenchido com Tris 30 mmol L-1 / HCl 10 mmol L-1 usado como BGE. Os resultados obtidos com o sistema EC-CE-C4D apontaram maior conversão dos álcoois nos respectivos ácidos carboxílicos em meio ácido, tanto em ouro quanto em platina. Adicionalmente, em eletrodo de ouro a formação dos carboxilatos apresentou certa seletividade não observada sobre platina, favorecendo a conversão dos álcoois de cadeia menor. Noutra vertente, buscando atender as necessidades atuais por metodologias que possibilitem monitorar a eletrooxidação do glicerol em reatores eletroquímicos, desenvolveu-se um método que permitiu determinar simultaneamente o glicerol e alguns de seus possíveis produtos de oxidação neutros, como gliceraldeído e dihidroxiacetona, explorando a formação de complexo carregado com borato (presente no BGE composto por H3BO3 60 mmol L-1 / LiOH 30 mmol L-1), além dos produtos ionizáveis (ácidos carboxílicos) que são comumente analisados por CE. O equipamento de CE utilizado, munido de dois detectores C4D, também permitiu avaliar a interação de alguns ácidos carboxílicos com os modificadores de EOF, Polybrene® e CTAB, empregando MES 30 mmol L-1 / His 30 mmol L-1 como BGE. Seguindo a atual tendência à miniaturização de sistemas analíticos, avaliou-se a possibilidade de construir um sistema EC-CE-C4D miniaturizado. Para isso, um novo método para fabricação de microdispositivos em vidro, baseado em ablação a laser de CO2 assistida por parafina, como alternativa aos dispendiosos métodos de corrosão por via úmida foi desenvolvido. Os dispositivos obtidos por esse método apresentaram canais de perfil semicircular, e as dimensões puderam ser controladas variando a potência e/ou a velocidade de ablação do laser. Contudo, pelos desafios ainda encontrados para se construir um sistema EC-CE-C4D completo em substrato de vidro por ablação a laser de CO2, optou-se por iniciar a miniaturização do sistema EC-CE-C4D com um sistema híbrido em que se aproveita as características mais bem definidas e favoráveis dos tubos capilares de sílica fundida usados em CE convencional. Esse sistema permitiu a determinação quantitativa de metanol na presença de alta concentração de etanol, possibilitando, numa primeira aplicação, realizar o monitoramento da quantidade de metanol e etanol nas frações iniciais coletada durante o processo de destilação fracionada na produção de uísque de milho (moonshine) feito em laboratório. Visto a maior seletividade para conversão dos álcoois de cadeia menor obtidas em eletrodo de ouro e meio ácido, esse foi escolhido para a presente aplicação. As condições que apresentaram melhores resultados no sistema híbrido EC-CE-C4D abrangeram diluição de 100 vezes da amostra em HNO3 2 mmol L-1, eletrooxidação a 1,4 V vs. Ag durante 60 s, injeção eletrocinética no capilar mediante aplicação de 3 kV durante 4 s, e a separação dos carboxilatos realizada aplicando 3 kV entre as extremidades do capilar (50 µm d.i., 15 cm de comprimento com 12 cm efetivo), preenchido com CHES 10 mmol L-1 / NaOH 5 mmol L-1, usado como BGE. A análise das primeiras frações destiladas da \"labmade moonshine\" apresentou um aumento na concentração de etanol (variando de ~80 % a ~100 %) e simultâneo decréscimo da concentração de metanol (variando de 4 % a ~0,1 %). Em suma, avançou-se tanto no leque de aplicações da derivatização eletroquímica hifenizada com a eletroforese capilar como na miniaturização da instrumentação analítica para EC-CE-C4D, favorecendo a disseminação dessa poderosa combinação de três técnicas eletroquímicas. / The direct couple of electrochemical cell (EC) with the inlet of the capillary electrophoresis (CE) equipment, recently demonstrated, has allowed the determination of radical anions; to perform electrochemical preconcentration of traces of heavy metals, followed by stripping, injection, separation and detection; and the generation of charged species by electrochemical oxidation of neutral molecules, e.g. primary alcohols and glycerol. Employing the EC-CE-C4D system developed by our group, the simultaneous determination of cations, anions (in the counter EOF mode) and neutral species (after electrochemical derivatization) was demonstrated for the first time and a mouthwash (Listerine® Tartar Control) was used as a real sample. Although constant and reproducible, the conversion of primary alcohols into carboxylates had a low yield (~16%), under the adopted conditions, 1.6 V vs. Ag/AgClKCl 3M using platinum electrode in acid medium (5 mmol L-1 HNO3 / 1 mmol L-1 HCl). Thus, the yield of carboxylates was studied for the oxidation of alcohols (C2 − C5) on two electrode materials (gold and platinum) in different media (acid, neutral and alkaline). After the electrooxidation step an aliquot of the derivatized sample was automatically injected into the capillary (50 µm i.d., 45 cm in length and 20 cm up to detector) by applying 5 kPa during 5 s. The separation was carried out applying 30 kV between the capillary ends previously filled with 30 mmol L-1 Tris / 10 mmol L-1 HCl BGE. Cyclic voltammograms show higher current density for alcohols oxidation in alkaline medium than in acid one both on gold and platinum electrodes. On the other hand the yields of carboxylic acids were higher in acidic medium. Besides that, only on gold electrode some selectivity for the carboxylate formation was observed favoring the conversion of the short chain alcohols. In order to meet the current needs for methodologies that allow the monitoring of the electrooxidation of glycerol in electrochemical reactors, a method was also developed that allowed the determination of glycerol and some of its possible neutral oxidation products, such as glyceraldehyde and dihydroxyacetone, by exploring the formation of borate complexes (provided in the BGE composed of 60 mmol L-1 H3BO3 / 30 mmol L-1 LiOH), together with ionizable ones like carboxylic acids. The employed CE equipment with two C4D detectors allowed the evaluation of the interaction between some carboxylic acids and the EOF modifiers, Polybrene® and CTAB, using 30 mmol L-1 MES / 30 mmol L-1 His as BGE. Aligned with a current trend of analytical instrumentation, the miniaturized EC-CE-C4D system was attempted. For that, a new method for manufacturing microdevices in glass, based on paraffin-assisted CO2 laser ablation, was developed as an alternative to costly wet-etching methods. The devices obtained by this method presented channels of semicircular profile and the dimensions could be controlled by varying the laser power and/or ablation velocity. Due to remaining challenges in the construction of a complete laser ablated EC-CE-C4D system on glass, a miniaturized system based on a hybrid approach is presented in the thesis, by taking advantage of the more defined and favorable characteristics of the well known fused silica capillary tubes used in CE. This system allowed the quantitative determination of methanol in the presence of high ethanol concentration by taking advantage of the higher yield of short-chain carboxylic acid formation on gold in acidic medium. The first application was the monitoring of the amount of methanol and ethanol in the initial fractions collected during the fractional distillation process in the production of corn whiskey (moonshine) made in the laboratory. The conditions that showed the best results with the hybrid EC-CE-C4D system included a 100-fold dilution of the sample in 2 mmol L-1 HNO3, electrooxidation at 1.4 V vs. Ag for 60 s, electrokinetic injection into the capillary by applying 3 kV for 4 s and separation of the carboxylates carried out under 3 kV between the ends of the capillary (50 µm i.d., 15 cm in length and 12 cm up to detector) previously filled with 10 mmol L-1 CHES / 5 mmol L-1 NaOH, used as BGE. Analysis of the first distilled fractions of labmade moonshine showed an increase in ethanol concentration (ranging from ~ 80% to ~ 100%) and a simultaneous decrease in methanol concentration (ranging from 4% to ~ 0.1%). In short, both the range of applications of electrochemical derivatization hyphenated with capillary electrophoresis as well the miniaturization of analytical instrumentation for EC-CE-C4D were improved, favoring the dissemination of this powerful combination of three electrochemical techniques.

A combinação de célula eletroquímica (EC) com a entrada do equipamento de eletroforese capilar (CE), apesar de recente, tem permitido realizar determinação de ânions radicais; pré-concentração eletroquímica de metais pesados, seguida de redissolução, separação e detecção; bem como monitorar produtos carregados formados por oxidação eletrocatalítica de espécies neutras, como álcoois primários e glicerol. Empregando o sistema EC-CE-C4D desenvolvido pelo grupo, a determinação simultânea de cátions, ânions (no contra fluxo) e espécies neutras (detectadas após derivatização eletroquímica) foi demonstrada pela primeira vez, tendo o antisséptico bucal (Listerine® Tartar Control) como amostra real. Embora constante e reprodutível, a conversão dos álcoois primários nos respectivos carboxilatos apresentou rendimento relativamente baixo, ~16%, nas condições anteriormente adotadas, 1,6 V vs. Ag/AgClKCl 3M empregando eletrodo de platina em meio ácido (HNO3 5 mmol L-1 / HCl 1 mmol L-1). Dessa maneira, avaliou-se a oxidação de álcoois primários de cadeia normal (C2 − C5) sobre diferentes materiais de eletrodo (ouro e platina) em diferentes meios (ácido, neutro e alcalino). Os carboxilatos gerados foram monitorados injetando uma alíquota da amostra derivatizada no capilar (50 µm d.i., 45 cm de comprimento e 20 cm efetivo) aplicando 5 kPa durante 5 s, e durante as separações, 30 kV foi aplicado entre as extremidades do capilar preenchido com Tris 30 mmol L-1 / HCl 10 mmol L-1 usado como BGE. Os resultados obtidos com o sistema EC-CE-C4D apontaram maior conversão dos álcoois nos respectivos ácidos carboxílicos em meio ácido, tanto em ouro quanto em platina. Adicionalmente, em eletrodo de ouro a formação dos carboxilatos apresentou certa seletividade não observada sobre platina, favorecendo a conversão dos álcoois de cadeia menor. Noutra vertente, buscando atender as necessidades atuais por metodologias que possibilitem monitorar a eletrooxidação do glicerol em reatores eletroquímicos, desenvolveu-se um método que permitiu determinar simultaneamente o glicerol e alguns de seus possíveis produtos de oxidação neutros, como gliceraldeído e dihidroxiacetona, explorando a formação de complexo carregado com borato (presente no BGE composto por H3BO3 60 mmol L-1 / LiOH 30 mmol L-1), além dos produtos ionizáveis (ácidos carboxílicos) que são comumente analisados por CE. O equipamento de CE utilizado, munido de dois detectores C4D, também permitiu avaliar a interação de alguns ácidos carboxílicos com os modificadores de EOF, Polybrene® e CTAB, empregando MES 30 mmol L-1 / His 30 mmol L-1 como BGE. Seguindo a atual tendência à miniaturização de sistemas analíticos, avaliou-se a possibilidade de construir um sistema EC-CE-C4D miniaturizado. Para isso, um novo método para fabricação de microdispositivos em vidro, baseado em ablação a laser de CO2 assistida por parafina, como alternativa aos dispendiosos métodos de corrosão por via úmida foi desenvolvido. Os dispositivos obtidos por esse método apresentaram canais de perfil semicircular, e as dimensões puderam ser controladas variando a potência e/ou a velocidade de ablação do laser. Contudo, pelos desafios ainda encontrados para se construir um sistema EC-CE-C4D completo em substrato de vidro por ablação a laser de CO2, optou-se por iniciar a miniaturização do sistema EC-CE-C4D com um sistema híbrido em que se aproveita as características mais bem definidas e favoráveis dos tubos capilares de sílica fundida usados em CE convencional. Esse sistema permitiu a determinação quantitativa de metanol na presença de alta concentração de etanol, possibilitando, numa primeira aplicação, realizar o monitoramento da quantidade de metanol e etanol nas frações iniciais coletada durante o processo de destilação fracionada na produção de uísque de milho (moonshine) feito em laboratório. Visto a maior seletividade para conversão dos álcoois de cadeia menor obtidas em eletrodo de ouro e meio ácido, esse foi escolhido para a presente aplicação. As condições que apresentaram melhores resultados no sistema híbrido EC-CE-C4D abrangeram diluição de 100 vezes da amostra em HNO3 2 mmol L-1, eletrooxidação a 1,4 V vs. Ag durante 60 s, injeção eletrocinética no capilar mediante aplicação de 3 kV durante 4 s, e a separação dos carboxilatos realizada aplicando 3 kV entre as extremidades do capilar (50 µm d.i., 15 cm de comprimento com 12 cm efetivo), preenchido com CHES 10 mmol L-1 / NaOH 5 mmol L-1, usado como BGE. A análise das primeiras frações destiladas da \"labmade moonshine\" apresentou um aumento na concentração de etanol (variando de ~80 % a ~100 %) e simultâneo decréscimo da concentração de metanol (variando de 4 % a ~0,1 %). Em suma, avançou-se tanto no leque de aplicações da derivatização eletroquímica hifenizada com a eletroforese capilar como na miniaturização da instrumentação analítica para EC-CE-C4D, favorecendo a disseminação dessa poderosa combinação de três técnicas eletroquímicas. / The direct couple of electrochemical cell (EC) with the inlet of the capillary electrophoresis (CE) equipment, recently demonstrated, has allowed the determination of radical anions; to perform electrochemical preconcentration of traces of heavy metals, followed by stripping, injection, separation and detection; and the generation of charged species by electrochemical oxidation of neutral molecules, e.g. primary alcohols and glycerol. Employing the EC-CE-C4D system developed by our group, the simultaneous determination of cations, anions (in the counter EOF mode) and neutral species (after electrochemical derivatization) was demonstrated for the first time and a mouthwash (Listerine® Tartar Control) was used as a real sample. Although constant and reproducible, the conversion of primary alcohols into carboxylates had a low yield (~16%), under the adopted conditions, 1.6 V vs. Ag/AgClKCl 3M using platinum electrode in acid medium (5 mmol L-1 HNO3 / 1 mmol L-1 HCl). Thus, the yield of carboxylates was studied for the oxidation of alcohols (C2 − C5) on two electrode materials (gold and platinum) in different media (acid, neutral and alkaline). After the electrooxidation step an aliquot of the derivatized sample was automatically injected into the capillary (50 µm i.d., 45 cm in length and 20 cm up to detector) by applying 5 kPa during 5 s. The separation was carried out applying 30 kV between the capillary ends previously filled with 30 mmol L-1 Tris / 10 mmol L-1 HCl BGE. Cyclic voltammograms show higher current density for alcohols oxidation in alkaline medium than in acid one both on gold and platinum electrodes. On the other hand the yields of carboxylic acids were higher in acidic medium. Besides that, only on gold electrode some selectivity for the carboxylate formation was observed favoring the conversion of the short chain alcohols. In order to meet the current needs for methodologies that allow the monitoring of the electrooxidation of glycerol in electrochemical reactors, a method was also developed that allowed the determination of glycerol and some of its possible neutral oxidation products, such as glyceraldehyde and dihydroxyacetone, by exploring the formation of borate complexes (provided in the BGE composed of 60 mmol L-1 H3BO3 / 30 mmol L-1 LiOH), together with ionizable ones like carboxylic acids. The employed CE equipment with two C4D detectors allowed the evaluation of the interaction between some carboxylic acids and the EOF modifiers, Polybrene® and CTAB, using 30 mmol L-1 MES / 30 mmol L-1 His as BGE. Aligned with a current trend of analytical instrumentation, the miniaturized EC-CE-C4D system was attempted. For that, a new method for manufacturing microdevices in glass, based on paraffin-assisted CO2 laser ablation, was developed as an alternative to costly wet-etching methods. The devices obtained by this method presented channels of semicircular profile and the dimensions could be controlled by varying the laser power and/or ablation velocity. Due to remaining challenges in the construction of a complete laser ablated EC-CE-C4D system on glass, a miniaturized system based on a hybrid approach is presented in the thesis, by taking advantage of the more defined and favorable characteristics of the well known fused silica capillary tubes used in CE. This system allowed the quantitative determination of methanol in the presence of high ethanol concentration by taking advantage of the higher yield of short-chain carboxylic acid formation on gold in acidic medium. The first application was the monitoring of the amount of methanol and ethanol in the initial fractions collected during the fractional distillation process in the production of corn whiskey (moonshine) made in the laboratory. The conditions that showed the best results with the hybrid EC-CE-C4D system included a 100-fold dilution of the sample in 2 mmol L-1 HNO3, electrooxidation at 1.4 V vs. Ag for 60 s, electrokinetic injection into the capillary by applying 3 kV for 4 s and separation of the carboxylates carried out under 3 kV between the ends of the capillary (50 µm i.d., 15 cm in length and 12 cm up to detector) previously filled with 10 mmol L-1 CHES / 5 mmol L-1 NaOH, used as BGE. Analysis of the first distilled fractions of labmade moonshine showed an increase in ethanol concentration (ranging from ~ 80% to ~ 100%) and a simultaneous decrease in methanol concentration (ranging from 4% to ~ 0.1%). In short, both the range of applications of electrochemical derivatization hyphenated with capillary electrophoresis as well the miniaturization of analytical instrumentation for EC-CE-C4D were improved, favoring the dissemination of this powerful combination of three electrochemical techniques.

Microelectromechanical systems (MEMS) based artificial sensory hairs for flow sensing have been widely explored, but the processes involved in their fabrication are lithography intensive, making the process quite expensive and cumbersome. Most of these devices are also based on silicon MEMS, which makes the fabrication of out-of plane 3D flow sensors very challenging. This thesis aims to develop new fabrication technologies based on Polymer MEMS, with minimum dependence on lithography for the fabrication of piezoresistive 3D out-of-plane artificial sensory hairs for sensing of air flow. Moreover, the fabrication of a flexible sensor array is proposed and new materials are also explored for the sensing application. Soft lithography based approaches are first investigated for the fabrication of an all elastomer device that is tested in a bench top wind tunnel. Micromolding technologies allow for the mass fabrication of microstructures using a single, reusable mold master that is fabricated by SU-8 photolithography, reducing the need for repetitive processing. Polydimethylsiloxane (PDMS) is used as the device material and sputter deposited gold is used as both the piezoresistive as well as the electrode material for collection of device response. The fabrication results of PDMS to PDMS metal transfer micromolding (MTM) are shown and the limitations of the process are also discussed. A dissolving mold metal transfer micromolding process is then proposed and developed, which overcomes the limitations of the conventional MTM process pertinent to the present application. Testing results of devices fabricated using the dissolving mold process are discussed with emphasis on the role of micro-cr  acking as one failure mode in elastomeric devices with thin film metal electrodes. Finally, a laser microfabrication based approach using thin film Kapton as the device material and an electrically conductive carbon-black elastomer composite as the piezoresistor is proposed and demonstrated. Laminated sheets of thick and thin Kapton form the flexible substrate on which the conductive elastomer piezoresistors are stencil printed. Excimer laser ablation is used to make the micro-stencil as well as to release the Kapton cantilevers. The fluid-structure interaction is improved by the deposition of a thin film of silicon dioxide, which produces a stress-gradient induced curvature, strongly enhancing the device sensitivity. This new approach also enables the fabrication of backside interconnects, thereby addressing the commonly observed problem of flow intrusion while using conventional interconnection technologies like wire-bonding. Devices with varying dimensions of the sensing element are fabricated and the results presented, with smallest devices having a width of 400 microns and a length of 1.5 mm with flow sensitivities as high as 60 Ohms/m/s. Recommendations are also proposed for further optimization of the device.

<p>Metamaterials are artificially structured materials which attain their unconventional macroscopic properties from their cellular configuration rather than their constituent chemical composition. The judicious design of this cellular structure opens the possibility to program and control the optical, mechanical, acoustic, or thermal responses of metamaterials. This Ph.D. dissertation focuses on scalable design and manufacturing strategies for optical and mechanical metamaterials.<br> <br> </p> <p>The fabrication of optical metamaterials still relies heavily on low-throughput process such as electron beam lithography, which is a serial technique. Thus, there is a growing need for the development of high-throughput, parallel processes to make the fabrication of optical metamaterials more accessible and cost-effective. The first part of this dissertation presents a scalable manufacturing method, termed “roll-to-roll laser induced superplasticity” (R2RLIS), for the production of flexible optical metamaterials, specifically metallic near-perfect absorbers. R2RLIS enables the rapid and inexpensive fabrication of ultra-smooth metallic nanostructures over large areas using conventional CO₂ engravers or inexpensive diode lasers. Using low-cost metal/epoxy nanomolds, the minimum feature size obtained by R2RLIS was <40 nm, facilitating the rapid fabrication of flexible near-perfect absorbers at visible frequencies with the capability to wrap around non-planar surfaces.</p> <p> </p> <p>The existing approaches for designing mechanical metamaterials are mostly <i>ad hoc</i>, and rely heavily on intuition and trial-and-error. A rational and systematic approach to create functional and programmable mechanical metamaterials is therefore desirable to unlock the vast design space of mechanical properties. The second part of this dissertation introduces a systematic, algorithmic design strategy based on Voronoi tessellation to create architected soft machines (ASMs) and twisting mechanical metamaterials (TMMs) with programmable motion and properties. ASMs are a new class of soft machines that benefit from their 3D-architected structure to expand the range of mechanical properties and behaviors achievable by 3D printed soft robots. On tendon-based actuation, ASMs deform according to the topologically encoded buckling of their structure to produce a wide range of motions such as contraction, twisting, bending, and cyclic motion. TMMs are a new class of chiral mechanical metamaterials which exhibit compression-twist coupling, a property absent in isotropic materials. This property manifests macroscopically and is independent of the flexible material chosen to fabricate the TMM. The nature of this compression-twist coupling can be programmed by simply tuning two design parameters, giving access to distinct twisting regimes and tunable onset of auxetic (negative Poisson’s ratio) behavior. Taking a metamaterial approach toward the design of soft machines substantially increases their number of degrees of freedom in deformation, thus blurring the boundary between materials and machines.</p>

This master’s thesis has been elaborated as a part of master’s studies of engineering technology M2I-K, major in M-STM – Engineering technology and industrial management and deals with the problem of a transition to a self-production of previously purchased distance washers. Distance washers were purchased in six different types of similar shape, each type in four different thicknesses. One of these types was chosen as a representative for this master’s thesis. We shall explore the possibilities of self-production with the emphasis on economical validation of the transition. The distance washer is a flat part, the intermediate being sheet metal. Technologies considered for manufacturing the washers correspond to the technical facilities and equipment available at the production hall of the company this project is planned for. The company possesses technology for CO2 laser cutting, cutting by CNC punching machine and cutting in the punching tool. To provide a complex overview we shall also enquire into cooperated technologies such as water jet and plasma cutting, oxy-acetyleny cutting and CNC working. All options are evaluated with regard to the production expenses and lead to a most economically plausible method of manufacturing or, if need be, give reasons for going back to purchasing the part from the current supplier.

Traditional fabrication methods used to manufacture biosensors for physiological, therapeutics, or health monitoring purposes are complex and rely on costly materials, which has hindered their adoption as single-use medical devices. The development of a new kind of wearable and implantable electronics relying on inexpensive materials for their manufacturing will pave the way towards the ubiquitous adoption of sticker-like health tracking devices.<div>One of growing and most promising applications for biosensors is the continuous health monitoring using mechanically soft, stretchable sensors. While these healthcare devices showed an excellent compatibility with human tissues, they still need highly trained personnel to perform multi-step, prolonged fabrication for several functioning layers of the device. In this dissertation, I propose low-cost, scalable, simple, and rapid manufacturing techniques to fabricate multifunctional epidermal and implantable sensors to monitor a range of biosignals including heart, muscle, or eye activity to characterizing of biofuids such as sweat. I have also used these devices as an implant to provide heat therapy for muscle regeneration and optical stimulation of neurons using optogenetics. These devices have also combined with those of triboelectric<br>nanogenerators to realize self-powered sensors for monitoring imperceptible mechanical biosignals such as respiratory and pulse rate.</div><div>Food health and safety has also emerged as another important frontier to develop biosensors and improve the human health and quality of life. The recent progresses on detecting microbial activity inside foods or their packages rely on development of highly functional materials. The existing materials for fabrication of food sensors, however,<br>are often costly and toxic for human health or the environment. In this dissertation, I proposed biocompatible food sensors using protein/PCL microfibers to reinforce the protein microfibrous structure in humid conditions and exploit their excellent hygroscopic properties to sense biogenic gas, as an indicator for early detection of food spoilage. Finally, my battery-free food sensors are capable of monitoring food safety with no need of extra measurement devices. Collectively, this dissertation proposes cost-effective solutions to solve human health issues, enabled by developing low-cost, functional materials and exploiting simple fabrication techniques.<br></div>