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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
341

Additively Manufactured Conformal Microwave Sensors for Applications in Oil Industry

Karimi, Muhammad Akram 11 1900 (has links)
Depleting oil reserves and fluctuating oil prices have necessitated to increase the efficiency of oil production process. This thesis is focused on developing low-cost sensors, which can increase oil production efficiency through real-time monitoring of oil wells and help in safe transport of oil products from the wells to the refineries. Produced fluid from an oil well is a complex mixture of oil, water and gases, which needs to be quantified for various strategic and operational decisions. For many years, test separators have been used to separate oil, water and gases into three separate streams and then to analyse them individually. However, test separators are being replaced by multiphase flow meters (MPFM) which can analyse the complex mixture of oil, water and gas without separating it. However, existing MPFMs are either intrusive or require fluid mixing before the sensing stage. In contrast to existing techniques, first part of this thesis presents a microwave sensor, which can measure water fraction in oil in a non-intrusive way without requiring it to be mixed. Gas fraction sensing can also be performed using the same microwave sensor, which is an on-going work. The sensor operates on dielectric measurement principles and comprises a microstrip T-resonator that has been optimized for a 3D pipe surface. Certain locations on an oil field have limited available space, for which we have also presented a compact version of the microwave water-fraction sensor in this thesis. In this version, metallic housing of the sensor has been used to function as a ground plane for the coaxially located spiral resonator. This housing also protects the sensor from environmental effects. In addition to the efficient production of oil, its safe transport is also a concern for the industry. It is physically impossible to inspect a network of thousands of kilometres of pipelines manually. The existing leak detectors suffer from low sensitivity, high false alarms and dependence on environmental effects. In the last part of this thesis, we present a flexible ringresonator based leak detector, which can be clamped at vulnerable locations along the pipeline for early leak detection.
342

Characterization of Flexible Hybrid Electronics Using Stretchable Silver Ink and Ultra-Thin Silicon Die

Ledgerwood, Joshua A. 01 June 2017 (has links)
Flexible Hybrid Electronics (FHEs) offer many advantages to the future of wearable technology. By combining the dynamic performance of conductive inks, and the functionality of ultra-thinned, traditional IC technology, new FHE devices allow for development of applications previously excluded by relying on a specific type of electronics technology. The characterization and reliability analysis of stretchable conductive inks paired with ultra-thin silicon die in theµm range was conducted. A silver based ink designed to be stretchable was screen printed on a TPU substrate and cured using box oven, conveyor convection oven, and photonic curing processes. Reliability tests were conducted including a tape test, crease test, wash test, and abrasion test. Optimization of each curing process resulted in all three methods’ ability to achieve the ink sheet resistance specification of <75mΩ/square/25µm. Reliability tests on the printing concluded that, if fully cured, all samples achieve similar reliability performance. Additionally, a series of 10 mm x 10 mm ultra-thin die were characterized using stylus profilometry and optical measurement in order to test the die quality and readiness for assembly. The die had been thinned from an initial thickness down of 600 µm to a target of 50 µm. A direct inverse relationship was shown between die thickness and die warpage, likely due to high levels of internal stress caused by the dicing and thinning process. Finally, an innovate pairing of serpentine copper clad traces on TPU was tested for reliability performance using traditional solder for die attachment.
343

Konstrukce GPS přístroje / Construction of The GPS Devices

Hort, Marek January 2010 (has links)
Aim of this Diploma thesis was to create a device capable of receiving navigational data from GPS. These data are subsequently stored in fixed memory and after connection with the PC are displayed it on the satellite map. The device was realized by using FPGA and GPS module LEA-5s. Description was created in the VHDL language, which was implemented into the circuit. The part of VHDL design was description of PICOBLAZE processor that controls whole system. For displaying and archiving data stored in device was created PC application GPS TRACER. It is able to display stored trace on the satellite map by using Google maps server. For created device were designed and manufactured PCBs, which were manually fitted.
344

Řídicí obvody výukového laboratorního standu / Control board for educational laboratory stand

Cejpek, Miroslav January 2013 (has links)
This work deals with the design scheme and printed circuit boards for drives teaching laboratory Stand, for teaching at the Department of Power Electrical and Electronic VUT Brno.
345

Elektrochemický biosenzor pro detekci glukózy / Electrochemical biosensor for glucose detection

Matula, Tomáš January 2016 (has links)
This thesis pays attention to electrochemical sensors for the detection of glucose. The theoretical part deals with the technology of thick film, their application and firing. It is further described electrochemistry, electrodes used in electrochemistry and analytical methods based on electrochemical reaction. End of theoretical part deals with electrochemical biosensors for detection glucose using special electrodes based on enzyme glucose oxidase. In the experimental part is processed amperometric measure for detection glucose using screenprinted sensors S10 and S8 with immobilized enzyme glucose oxidase. Next was studied effect of plasma, dissolved potassium chloride, storage, ascorbic acid and the reproducibility of the sensors.
346

Design of a Robotic Cannula for Robotic Lumbar Discectomy

Yang Ding (6866906) 16 December 2020 (has links)
<div>In this thesis, the design of the robotic cannula for minimally invasive robotic lumbar discectomy is presented. Lumbar discectomy is the surgery to remove the herniated disc material that is pressing on a nerve root or spinal cord. </div><div><br></div><div>Recently, a robotic approach to performing this procedure has been proposed that utilizes multiple teleoperated articulated instruments inserted into the surgical workspace using a single cannula. In this paper, a new robotic cannula system to work in conjunction with this new procedure is presented. It allows for the independent teleoperated control of the axial position and rotation of up to three surgical instruments at the same time. The mechanical design, modeling, controller design, and the performance of the prototype of the new system are presented in this paper demonstrating a fully functioning device for this application. A novel worm gear and rack system allow for the instrument translation while and embedded gear trains produce the rotational movement. Steady-state errors of less than 10 microns for translation and less than 0.5 degree for rotation motion are achieved in position tracking; steady-state errors of less than 100 micron per second of translation and less than 0.5 degree per second for rotation motion are obtained in speed tracking. </div>
347

Diffusion Kinetics and Microstructure of Eutectic and Composite Solder/Copper Joints

Wu, Yujing 05 1900 (has links)
Sn/Pb solders are widely used by the electronics industry to provide both mechanical and electrical interconnections between electronic components and printed circuit boards. Solders with enhanced mechanical properties are required for high reliability for Surface Mount Technology (SMT) applications. One approach to improve the mechanical properties of solder is to add metallic or intermetallic particles to eutectic 63Sn/37Pb solder to form composite solders. Cu6Sn5 and Cu3Sn form and grow at the solder/copper substrate interface. The formation and growth of these intermetallics have been proposed as controlling mechanisms for solderability and reliability of solder/copper joints. The goal of this study was to investigate the diffusion kinetics and microstructures of six types of composite solder/copper joints.
348

PCB design of Power Distributor Unit (PDU)

Machuca, Julían, Tuvesson, Thomas January 2020 (has links)
The project idea was created from the demand of a renewal for a Power Distributor Unit also known as a PDU. The current product had successively turned in to a cable mess because of short term solutions. This made the product non user friendly, inconvenient and non-agile to handle troubleshooting. To develop this project, a PCB design was created by simplifying and improving circuit diagrams until satisfied. Once the final circuit diagram was obtained, a PCB layout design was created. The result of the project, due to limited time, was only theoretical. The finished product was not tested as there was no time allowing this.
349

Outdoor Stability Testing of Printed Organic Solar Cells for Indoor Applications / Stabilitetstester Utomhus av Printade Organiska Solceller Optimerade för Inomhusbruk

Hekkala, Cathrine January 2020 (has links)
Renewable energy is required for a sustainable future and one way to meet this is with organic solar cells (OSCs). The OSC can be easily manufactured at a low cost, be lightweight and be used on flexible surfaces. If the efficiency in high illumination intensities and stability in harsh environments increase for OSCs, they can com- pete with the other technologies even in outdoor conditions. Another advantage of OSCs is their good performance under low-light and indoor conditions. This is utilized by Epishine, a Swedish company based in Linköping working with small, thin and flexible organic printed solar cells optimized for indoor applications. The goal of this thesis is to determine how Epishine’s solar cells for low-light indoor usage work in more challenging conditions and to identify which are the factors that are detrimental for the lifetime of the cells. The result showed that all modules had a similar initial electrical performance which indicates that the modules have high reproducibility and degradation in darkness is negligible (since the initial measurements were made at different times). The tests showed that the temperature affected the modules. The test in the oven showed a little less than half the degradation compared to tests under the solar simulator, although both tests were subjected to the same temperature. The hu- midity test and the test exposed to LED-light showed almost no degradation. For the levels exposed to the sun or simulated sunlight, the decrease of the short circuit current density shows a burn-in time, which is typical for organic solar cells. After the first couple of hours, the decrease slows down to a more linear behaviour. All modules that were exposed to bright light also showed some recovery effect for short circuit current density and efficiency after they have been kept in the dark. It would be interesting to investigate the behaviour of the modules after even more exposure and look into how the recovery effect works.
350

Zero-Energy Tuning of Silicon Microring Resonators Using 3D Printed Microfluidics and Two-Photon Absorption Induced Photoelectrochemical Etching of Silicon

Larson, Kevin Eugene 17 June 2021 (has links)
This thesis presents a novel method of modulating silicon photonic circuits using 3D printed microfluidic devices. The fluids that pass through the microfluidic device interact directly with the silicon waveguides. This method changes the refractive index of the waveguide cladding, thus changing the effective index of the system. Through using this technique we demonstrate the shift in resonant wavelength by a full free spectral range (FSR) by increasing the concentration of the salt water in the microfluidic device from 0% to 10%. On a 60 μm microring resonator, this equals a resonant wavelength shift of 1.514 nm when the index of the cladding changes by 0.017 refractive index units (RIU), or at a rate of 89.05 nm/RIU. These results are confirmed by simulations that use both analytical and numerical methods. This thesis also outlines the development of a process that uses two-photon absorption(TPA) in silicon to produce a photoelectrochemical (PEC) etching effect. TPA induces free carriers in silicon that then interact with the Hydroflouric Acid (HF) solution that the wafer is submerged in. This interaction removes silicon away from the wafer, which is the etching observed in our experiments. Non-line-of-sight PEC etching is demonstrated. The optical assemblies used in these experiments are presented, as are several of the results of the etching experiments.

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