Bioelectronics effectively bridges the gap between the biochemical and the electrical domains, integrating aspects of biology, electronics, physics, and material science to foster innovative solutions and impact the trajectory of human health and environmental science, by translating biological responses into electrical signals for advanced analysis. Despite its transformative potential, current bioelectronic systems face limitations in terms of scalability, sensitivity, and ease of integration. This thesis claims that co-designing Complementary Metal-Oxide-Semiconductor (CMOS) integrated circuits with highly specific and sensitive genetically engineered biosensors is pivotal in bioelectronics evolution, offering high accuracy, reliability, miniaturization, and multiplexed sensing capabilities essential for addressing challenges in healthcare, environmental monitoring, sustainable manufacturing, and beyond. To support this claim, this dissertation highlights two key contributions: a low-power ingestible sensor for gastrointestinal tract monitoring and a hybrid platform technology combining droplet microfluidics and CMOS electronics for impedance spectroscopy and luminescence sensing for rapid screening and optimization of biosensors under different environmental conditions. The first contribution details an ingestible capsule that could transform healthcare diagnostics through a novel threshold-crossing-based detector and CMOS-integrated photodiodes. This innovation exemplifies how hybrid bioelectronic systems can significantly improve the precision and non-invasiveness of real-time health monitoring. Moving beyond the traditional scope of bioelectronics and the sole purpose of health monitoring, the second contribution extends its application by integrating droplet microfluidics with CMOS chips, facilitating high-throughput droplet screening to optimize biosensor performance for application deployment. To achieve this goal, this platform is equipped with a low-noise, high-resolution CMOS impedance spectroscopy chip and a high-resolution CMOS luminescence detector chip. In highlighting these contributions, the thesis reinforces the assertion that hybrid bioelectronic systems are key to addressing a wide range of societal challenges. Moreover, the integration of synthetic biology and microfluidics with CMOS technology, as demonstrated in this work, not only overcomes existing barriers, such as achieving miniaturization, high sensitivity, rapid data processing, and energy efficiency, but also paves the way for future innovations with extensive potential in personalized medicine and environmental sustainability. / 2026-01-17T00:00:00Z

No description available.

This thesis presents an experimental study on how to track zero gaps between metal sheets to be joined by laser beam butt welding. Automated laser beam welding is gaining interest due to its ability to produce narrow and deep welds giving limited heat input and therefore less distortions compared to other processes, such as arc-welding. The automated laser beam welding process is however sensitive to how the high power laser is positioned with regards to the joint position. Deviations from the joint position may occur due to inaccuracies of the welding robot and fixturing, changes in joint geometry, process induced distortions, etc. Welding with an offset from the joint position can result inlack of sidewall fusion, a serious defect that is hard to detect. This work develops and evaluates three monitoring systems to be used during welding in order to be able to later control the laser beam spot position. (i) A monitoring systemis developed for three different photo diodes, one for the visual spectrum of the process emissions, one for the infrared spectrum, and one for the reflected highpower laser light. The correlation between the signals from the photodiodes and the welding position relative to the joint is analysed using a change detection algorithm. In this way an indication of a path deviation is given. (ii) A visual camera with matching illumination and optical filters is integrated into the laser beam welding tool in order to obtain images of the area in front of the melt pool. This gives a relatively clear view of the joint position even during intense spectral disturbances emitted from the process, and by applying animage processing algorithm and a model based filtering method the joint positionis estimated with an accuracy of 0.1 mm. (iii) By monitoring the spectral emissions from the laser induced plasma plume using a high speed and high resolution spectrometer, the plasma electron temperature can be estimated from the intensities of two selected spectral lines and this is correlated to the welding position and can be used for finding the joint position.

Our motivation for this work is based on the need to monitor the cure and inservice health of composite materials. We describe the continuation of an effort to design a multi-functional fiber optic sensor which can be embedded in polymeric composite laminates for monitoring the degree of cure during its fabrication, as well as internal composite strains occurring post-cure.3 In short, this dual-purpose sensor combines the characteristics of a Fresnel reflectometer with those of the extrinsic Fabry-Perot interferometer. For monitoring cure, a broadband source is used so the output intensity of the sensor is amplitude-modulated as the refractive index of the composite is increased during the polymerization process. Post-cure, a coherent light source is implemented so a. sinusoidal variation of the output signal occurs when strains within the composite cause the sensor output to be phase-modulated. We demonstrate the measurement of refractive index with the Fresnel reflectometer/EFPL and test it as an embedded refractive index monitor. Our experimental results demonstrate that the refractive index of 5-minute epoxy increases by approximately 2 % during the cure process. In addition, the sensor can be used as an interferometer to measure internal composite strains, where the phase difference between consecutive fringe peaks is one-half the wavelength of the source. / Master of Science

The examination of the application and accuracy of optical sensors for the purpose of determining rail lubricity of top-of-rail friction modifier is investigated in this research. A literature review of optical sensors as they relate to detecting thin layers is presented, as well as a literature review of the significant aspect of surface roughness on optical signature. Both commercially available optical sensors and optical devices, such as independent lasers and detectors, are examined in a comprehensive parametric study to determine the most suitable configuration for a prototype with adequate third-body detection. A prototype is constructed considering parameters such as sunlight contamination, vibrations, and angle of detection. The prototype is evaluated in a series of laboratory tests with known lubricity conditions for its accuracy of measurements and susceptibility to environmental conditions, in preparation for field testing. Upon field testing the prototype, the data indicates that it is capable of providing subjective measurements that can help with determining whether a rail is highly lubricated or unlubricated, or it is moderately lubricated. It is anticipated that the device could be used to provide a rail lubricity index. The investigation of the optical response of a rail in various conditions, including top-of-rail friction modifier presence and underlying surface roughness, reveals the behavior of friction modifying material on rail/wheel interactions. It is determined that surface roughness is imperative for distinguishing between scattering due to surface condition and scattering due to third-body layers. Additionally it is revealed that friction modifying materials become entrapped within the surface roughness of the rail, effectively causing a "seasoning" effect instead of a simple third body layer. This provides some explanation on the inadequacy of determining lubricity conditions using contacting methods since they cannot detect the entrapped material that are revealed only when the top of rail undergoes a micro deformation due to a passing wheel. Furthermore, the fluorescent signature of flange grease can be utilized to detect any flange grease contamination on top of rail. The results of the study indicate that it is possible to have practical optical sensors for top-of-rail third body layer detection and any contamination that may exist, initially through spot checking the rail and eventually through in-motion surveying. / Master of Science

Ion-selective polymeric optical sensors – ion optodes – are a promising alternative to ion-selective electrodes and fluorescent dyes for analytical and biological applications, e.g. extra- and intracellular measurements. They are non-toxic, highly selective robust probes for ionic fluxes monitoring. A large-scale fabrication of ion optodes using a solvent displacement method is introduced. This method is a single-batch process that does not require any additional steps. The influence of numerous parameters, e.g. surfactant concentration, solvent nature and membrane concentration, on the average size of the synthesized optodes was studied. The solvent displacement method allows control of the particle size in 200 nm to 30 μm range. Ion optodes selective for sodium, potassium, and calcium cations were prepared and calibrated for hydrogen (pH), sodium, potassium, and calcium. Fabricated sensors demonstrated excellent selectivity, low drift, high stability and reproducibility. Further studies of ion-optodes of different sizes but the same chemical composition revealed a significant shift in their response function. This bias is clearly seen for all fabricated optodes. A strong correlation between a calculated specific surface area and the apparent ion-exchange constant was observed. Considering this, it may be hypothesized that the surface phenomena are contributing to the overall optode response resulting in the observed effect. As a consequence, the response models, developed for the macroscopic ion optodes, cannot be easily applied to the probes at micron- and nano-scale. A primary concern for continuous sensing application of optical sensors is photobleaching of lipophilic fluorescent dye which prevents quantitative fluorescence measurements. Quantum dots, known for their high photostability, brightness and broad excitation spectra with narrow emission bands, were incorporated into polymeric matrix. They excited a fluorophore indirectly, thus, reducing its photobleaching and increasing sensors life-time. We created a composite, quantum dots doped, polymeric sensor that can be integrated into high-throughput detection platforms, such as flow cytometry, chip-based micro-total analysis system technologies, or bundled optical fiber arrays. Ultimately, a fabricated ion-optode was introduced into a Boolean logic gate serving as a reporting microparticle. It responded to the pH changes generated in situ by the enzyme logic system. The present work aimed scaling down the size of biocomputing functional units which might reach the information processing by single molecules associated with signal-transducing single nanoparticles. / Graduation date: 2012

Siekiant taupiai naudoti degalus, trąšas, sėklas, augalų apsaugos produktus, gerinti gaminamų produktų kokybę ir konkurencingumą Lietuvos ūkininkų ūkiuose pradedamos diegti tiksliojo ūkininkavimo (TŪ) priemonės. Tikslusis ūkininkavimas prasideda atskiro lauko derlingumo, maisto medžiagų ir dirvožemio tipo skirtumų nustatymu. Šių duomenų pagrindu galima tikslingai planuoti technologines operacijas ir analizuoti biomasės derliaus įvairovės priežastis. Šiame darbe pateikiami žieminių ir vasarinių kviečių tręšimo mineralinėmis trąšomis, panaudojant augalų optinės analizės jutiklius OptRx, tyrimai. Tirta tiksliojo tręšimo įtaka kviečių biometriniams rodikliams, grūdų kokybei ir užaugintos biomasės kiekiui. Tręšiant skystomis mineralinėmis trąšomis (karbamido tirpalu) ir trąšų normos parinkimui naudojant augalų optinės analizės jutiklius, vasarinių kviečių Tybalt grūdų kokybė buvo šiek tiek geresnė, negu tręšiant įprastai (vienoda trąšų norma). Įprastai tręštų vasarinių kviečių grūduose baltymų kiekis buvo 12,18 ± 0,12%, o tręštų naudojant augalų optinės analizės jutiklius OptRx – 12,79 ± 0,09%. Grūdų glitimas, atitinkamai, buvo: 31,08 ± 0,37% ir 31,9 ± 0,12%, grūdų kritimo skaičius – 338,33 ± 2,52 s ir 381 ± 3,61 s, o užaugintos biomasės (šiaudų) derlius – 7,07 ± 0,26 t/ha ir 7,46 ± 0,35 t/ha. / In order to sustainably use fuel, fertilizers, seeds, and crop protection products and improve quality and competitiveness of Lithuanian products, Lithuanian farms are introducing precision farming tools. Precision farming starts from the identification of the productivity of an individual field, the differences in its nutrient materials and soil types. Such data can be used for purposeful planning of technological operations and the analysis of the reasons of differences in biomass yield. This paper represents the research of winter and spring wheat fertilization in mineral fertilizers using optical sensors OptRx of crop analysis. The research comprises the influence of precision fertilization on wheat biometric parameters, grain quality, and biomass yield. Fertilizing in liquid mineral fertilizers (urea solution) using optical sensors OptRx, the quality of spring wheat Tybalt grains was a little bit better than usually (the same rate of fertilizers in the entire field). Grain protein content of conventionally fertilized spring wheat was 12.18 ± 0.12%, the same measure in plants fertilized using optical sensors OptRx was 12.79 ± 0.09%. Grain gluten was 31.08 ± 0.37% and 31.9 ± 0.12%, the falling number of grain was 338.33 ± 2.52 and 381.00 ± 3.61 s, and biomass (straw) yield was 7.07 ± 0.26 t/ha and 7.46 ± 0.35 t/ha, respectively.

Ce travail porte sur la conception de nouveaux composés π-conjugués, potentiellement utilisable en électronique organique en tant que matériaux actifs dans des dispositifs tels que les OLEDs, les cellules photovoltaïques et les capteurs optiques. Dans ce but, nous avons exploité le motif silacyclopentadiène appelé également silole, possédant un bon rendement quantique de fluorescence à l'état solide et une excellente conduction des électrons. Dans un premier temps, l'introduction de groupements structurants (triptycène, stilbènes..) sur le silacyclopentadiène a permis de moduler l'arrangement moléculaire dans la couche active et par conséquent, les propriétés d'électroluminescence. Des diodes possédant des performances très encourageantes furent ainsi obtenues. Dans un deuxième temps, des dérivés siloles présentant une structure tridimensionnelle et une architecture spirosilole (accepteur)-bithiophène (donneur) furent synthétisées. Une cellule photovoltaïque basée sur ces édifices présentant des performances encourageantes fut ensuite mis au point. Enfin, l'étude des mécanismes de transfert d'énergie entre un film de polymère fonctionnalisé par un groupement sensible silole et des composés nitroaromatiques nous a permis de réaliser un nouveau type de capteur optique hautement sensible pour la détection d'explosifs. / This work concerns the design of new π-conjugated compounds, potentially useful in organic electronics as active materials in devices such as OLEDs, photovoltaic cells and optical sensors. To this end, silacyclopentadiene, alias silole, groups were used exhibiting high fluorescence quantum yields in the solid state and excellent electron conductivities. Firstly, the introduction of structurizing groups (triptycene, stilbenes etc.) at the silacyclopentadiene allowed tuning of the molecular arrangement in the active layer and, consequently, the electroluminescence properties. Diodes showing very encouraging activities were thus obtained. Secondly, silole derivatives possessing a three-dimensional structure and a spirosilole (acceptor) - bithiophene (donor) architecture were synthesized. A photovoltaic cell based on these molecules was then developed exhibiting encouraging activity. Finally, a study of the mechanisms of energy transfer between a polymer film functionalized by a sensitive silole group and nitroaromatic compounds enabled the development of a new type of highly sensitive optical sensor for the detection of explosives.

O interesse no uso de técnicas de aquisição de dados 3D em vídeos interativos e sistemas de videoconferência imersiva aumentou significativamente nos últimos anos. A disponibilidade de sensores de profundidade baseados em luz estruturada no varejo apresenta uma série de novas oportunidades em sistemas de teleconferência, entretenimento e e-learning. No entanto, problemas de oclusão frequentemente ocorrem quando é utilizado um único sensor ou técnicas de reconstrução 2,5D. Outras técnicas de interação e aplicações de teleconferências podem exigir uma reconstrução mais completa do usuário. Uma possível solução para isso implica na utilização de múltiplos dispositivos simultaneamente, o que traz novos desafios relacionados ao processo de calibração de câmaras e a aferição do aumento da superfície capturada quando é adicionado um novo sensor. Neste trabalho é apresentada a proposta VMD (Video-avatar from Multiple Depth maps), uma arquitetura de sistema que trata esses dois problemas. Com a finalidade de validar a viabilidade dessa proposta, três experimentos foram feitos resultando em uma análise qualitativa e quantitativa a fim de encontrar uma configuração adequada de múltiplos sensores de profundidade. / The interest in the use of 3D data acquisition techniques in video based interaction and immersive videoconferencing systems has noticeably increased in recent years. The availability of structured light 3D sensors as off-the-shelf hardware presents a series of new opportunities in teleconferences, entertainment and e-learning. However, occlusion issues often occur when it is used a single sensor or 2,5D reconstruction techniques. Other interaction techniques and teleconferencing applications may require a more complete reconstruction of the user. One possible solution to this involves the use of multiple devices simultaneously, which may bring new challenges related to the calibration process of cameras and measurement of the increase in covered area when it is added a new sensor. In this work we present VMD (Video-avatar from Multiple Depth maps), a system architecture that addresses this two issues. In order to validate the feasibility of this proposal, three experiments were performed resulting in a qualitative and quantitative analysis with the purpose of finding a suitable setup with multiple depth sensors.

Neste trabalho foram produzidos Interferômetros Mach-Zehnder (IMZ) a partir de guias de onda do tipo pedestal com filmes finos de Bi₂O₃-WO₃-TeO₂ (BWT) como camada de núcleo para aplicações em sensores ópticos integrados. A influência dos parâmetros e dos materiais utilizados nas etapas de processo foi verificada. Os valores de índice de refração efetivo e coeficiente de absorção em função do comprimento de onda foram obtidos para os filmes finos BWT. Os guias de onda pedestais foram caracterizados por Microscopia Eletrônica de Varredura, medidas de perda por propagação e perfis de campo próximo em 633 nm e 1050 nm. Os valores mínimos obtidos nas perdas por propagação foram de ~1,5 dB/cm em 633 nm e 3,0 dB/cm em 1050 nm. As medidas de perfis de campo próximo mostraram que guias de onda com larguras superiores a 7 m apresentaram comportamento multimodo. Foram obtidos IMZs que apresentaram guiamento de luz por toda a estrutura, com comportamento multimodo. Sensores ópticos de pressão e temperatura foram produzidos. A fabricação de diafragmas através do processo de corrosão úmida do silício é apresentada no sensor de pressão. Sensores ópticos de temperatura foram produzidos com filamentos metálicos. As cavidades ópticas não foram obtidas nesse sensor. A potência de luz na saída dos sensores de temperatura foi medida em função da diferença de potencial aplicada no filamento metálico. Os resultados apresentados mostram que guias de onda do tipo pedestal produzidos com núcleo de BWT são promissores para aplicações em sensores ópticos integrados. / In this work Mach-Zehnder Interferometers (MZI) were produced from the pedestal-type waveguides with Bi₂O₃-WO₃-TeO₂ (BWT) thin films as the core layer for applications in integrated optical sensors. The influence of the parameters and materials used in the process steps was verified. The values of the effective refractive index and absorption coefficient as a function of wavelength were obtained for the BWT thin films. The pedestal waveguides were characterized by Scanning Electron Microscopy, by propagation loss measurements and near-field profiles at 633 nm and 1050 nm. The minimum values obtained by propagation losses were ~ 1.5 dB/cm at 633 nm and 3.0 dB/cm at 1050 nm. The measures of near-field profiles showed that waveguides with widths larger than 7 m presented multimode behavior. The MZIs obtained presented guiding light through the structure, with multimode behavior. Optical pressure sensors and temperature sensors were produced. The production of diaphragms using the wet etching process of silicon is presented on the pressure sensor. Optical temperature sensors were made with metallic filaments. Optical cavities were not obtained in this sensor. The light power in the output of the temperature sensors was measured as the voltage applied to the metal filament. The results show that the waveguides produced with pedestal-type and BWT thin films as core layer are promising for applications in integrated optical sensors.