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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.
211

Design av mönsterkort för kraftenhet / Design of PCB for power unit

Machuca Pilblad, Simón January 2020 (has links)
Denna rapport utreder möjligheten till en mönsterkortslösning för en kabelbaserad kraftenhet. Denna kraftenhet är en låda som består av flera komponenter som exempelvis kraftenheter för 24V, 100V, filter och motorstyrkort för två axlar samt kraftfördelning. Kablarna i enheten är tidskrävande och dessutom kostsamma. Därför har enheten idag både hög produktionskostnad och produktionstid. Kablarna tillför, utöver höga kostnader, risk för störningar och p.g.a. mängden kablar ökar svårigheten att felsöka enheten. Simuleringar har genomförts med LT-Spice för olika RC-filter för styrsignalerna i kraftenheten. Vidare har ett kretsschema konstruerats baserat på ritningen av lådan och alla kablar som ska reduceras och hanteras av mönsterkortet. Med kretsschemat skapades en layout för mönsterkortet. Denna layout representerar alla komponenter och hur kopparledningarna ska placeras. Det ledde till att mönsterkortet utvecklades som en möjlig lösning till kraftenheten. / This report investigates the possibility for a PCB (Printed circuit board) solution for a cable-based power unit. This power unit is a box which contains multiple components as for example power units for 24v, 100v, filter and motor control boards fort wo shafts and power supply. The cables in the unit are complicated and hard to construct and also expensive. Therefore, the unit has a high production cost and high production time. Besides high costs the cables also add risks for interference and because of the amount of cables it also raises the difficulty to debug the unit. Simulations have been done with LT-Spice for constructions of different RC-filters for the steering signals in the power unit. Furthermore, a circuit diagram has been drawn based on the drawing of the power unit and all the cables that are to be reduced and handled by the circuit board. The circuit board layout was designed based on the circuit diagram. Which led to a circuit board being developed as a possible solution for the power unit.
212

Organic Field Effect Transistor Semiconductor Blends for Advanced Electronic Devices Including UV Phototransistors and Single Walled Carbon Nanotube Enhanced Devices / OFET Semiconductor Blends for Advanced Electronic Devices

Smithson, Chad 11 1900 (has links)
Two major projects involving the use of solution processed blended semiconductors for organic field effect transistors (OFET) were explored. The first incorporated unsorted single walled carbon nanotubes (SWCNTs) into a diketopyrrolopyrrole-quarterthiophene (DPP-QT) semiconductor to enhance the mobility of the OFET. 2 wt % SWCNT was found to be the optimal blend ratio, nearly doubling the device mobility (0.6 to 0.98 cm^2/V·s). Beyond this ratio, the metallic content of the SWCNT’s dropped the on/off ratio below acceptable levels. When source drain metals who’s work function poorly matched that of the DPP-QT semiconductors highest occupied molecular orbital (HOMO) were used, the SWCNT could dramatically reduce the charge injection ratio with best results achieved for Al, dropping the contact resistance from 10^5 to 45 MΩ. The second project explored the addition of small molecule additives into a UV-sensitive semiconductor 2,7-dipentyl[1]benzothieno[3,2-b][1] benzothiophene (C5-BTBT) mixed with a polymethyl methacrylate (PMMA) polymer binder. We generated a C5-BTBT based phototransistor sensitive to UV-A light. The HOMO and lowest unoccupied molecular orbital (LUMO) of C5-BTBT and the various additives were measured and discovered to play a critical role in how the device operates. We discovered if an additive has a LUMO lower in energy than C5-BTBT, it can act as a charge trap for a photogenerated electron. Electron deficient additives were found to retain a trapped electron for an extended period of time, allowing the device to remain in a high current state for an extended period of time (>1 hour). This provides an opportunity for the device to be used as an optical memory system or photoswitch. The best system could detect UV-A with a Pill > 10^5 and a photoresponsivity of 40 A/W at a Pinc of 0.0427 mW/cm^2. / Thesis / Doctor of Philosophy (PhD) / An emerging field of electronics is the use of organic materials that can be solution processed, to reduce manufacturing costs and make new and interesting products. Here we used unsorted carbon nanotubes blended into the semiconductor layer of a transistor, providing a bridge for the energy mismatch between the electrodes and the semiconductor. This allowed us the freedom to choose different metals to act as our electrodes when making electronic devices. Additionally through the correct choice of semiconductor, we added device functionality, making it responsive to UV-A light. This produced a device that could act as a UV-A sensor, logic switch or memory device. These devices are air stable and solution processable, a necessity if they are to be used in real world applications.
213

Design of Autonomous Underwater Vehicle’s (AUV) Antenna System

Zhou, Chengzhuang January 2021 (has links)
The ocean symbolizes mystery, passion, and power. However, most of the ocean, about 80 %, is unknown to humans. AUVs (Autonomous Underwater Vehicles) provide a platform where terrain mapping, the biodiversity, and the resource survey of the ocean become accessible. Unlike ROVs (Remotely Operated Vehicle), AUVs operate according to their preset program which specifies the instructions required in different environments. One design aspects of AUVs that must be considered is that the data it acquire needs to be transmitted to a ground station (typically a ship). Although underwater acoustic communication is available nowadays, the low transmission rate and narrow bandwidth makes it unsuitable for large data transmission. For large sets of data, transmission with electromagnetic waves is more suitable. LoLo is an AUV which is designed and assembled at KTH Royal Institute of Technology, Sweden. Its wireless communication system consists of five components: RC (radio communication, 2.4 GHz), RF (radio frequency, 868 MHz), WIFI (wireless fidelity, 2.4 GHz), 4G (4th generation, 800 MHz, 1.8 GHz and 2.6 GHz) and GPS (global positioning system, 1.575 GHz). The goal of this project is to design an antenna board where the five subsystems are integrated. Importantly, due to the influence of seawater and waves, the resonant frequency of the antenna will fluctuate to a certain extent. Therefore, we need a robust, and preferably broadband, antenna system. In this project, we integrated printed dipole and monopole antennas on a single circuit board. The printed dipole antennas operate over a reasonable bandwidth and their radiation pattern is omnidirectional. The monopole antenna is designed to have multiple resonant frequencies which can cover BAND 20 (800 MHz) and BAND 3 (1.8 GHz) of the 4G service in Sweden. The 4G antenna shows good omnidirectional characteristics in the lower frequency band (band 20) and broadband characteristic in the higher frequency band. The upper 4G band is to be used to transmit large sets of data if a signal can be detected. The lower 4G band is added to provide redundancy. The antenna board is manufactured and measured. The results show the consistency with the simulation results and meets the requirement of the project. / Havet symboliserar mysterium, passion och kraft. Men det mesta av havet, cirka 80 %, är okänt för människor. AUVs (Autonomous Underwater Vehicles) är en plattform där terrängkartläggning, biologisk mångfald och resursundersökning blir tillgänglig. Till skillnad från ROVs (Remotely Operated Vehicles) fungerar AUVs enligt sitt förinställda program som specificerar de instruktioner som krävs i olika miljöer. Den data som den förvärvade måste överföras till en markstation (oftast en båt). Även om akustiska kommunikationen under vatten är möjlig idag gör den låga överföringshastigheten och den smala bandbredden den olämplig för stora dataöverföringar. I dessa fall är det bättre att överföra data med hjälp av elektromagnetiska vågor. LoLo är en AUV som är designad på KTH Royal Institute of Technology, Sverige. Dess trådlösa kommunikationssystem består av fem delsystem: RC (radiokommunikation, 2.4 GHz), RF (radiofrekvens, 868 GHz), WIFI (trådlös fidelity, 2.4 GHz), 4G (4 generationen av mobilnätverket, 800 MHz och 1.8 GHz) och GPS (global positioning system, 1.575 GHz). Målet med detta projekt är att designa antennerna för dessa fem delsystem. Viktigt att notera är antennernas resonansfrrekvens påverkas till viss del av havsvatten och vågor. Därför behövs vi ett robust, bredbandsantennsystem. I detta projekt integrerade vi dipolantenner och en monopolantenn på ett kretskort. Dipolantennerna har rimlig bandbredd och är omnidirektionella. Monopolantennen ger oss flera resonansfrekvenser som kan täcka Band 20 (800 MHz) och Band 3 (1.8 GHz) av 4Gspektrumet i Sverige. 4Gantennen visar omnidirektionella strålningsegenskaper i det lägre band et (band 20) och har vred bandbredd i det högre band et. Det högre bandet kommer användas för att skicka mycket data om en signal kan säkras. Det lägre bandet ger redundans. Antennen tillverkas och mäts i ett ekofritt rum. Mätresultaten stämmer överens med simuleringsresultaten och uppfyller projektets krav.
214

Metodologia de simulação numérica do comportamento térmico em equipamentos eletroeletrônicos /

Sousa, Reginaldo Ribeiro de. January 2015 (has links)
Orientador: Ailton Akira Shinoda / Banca: Amarildo Tabone Paschoalini / Banca: Marcio Antonio Bazani / Banca: Thiago Antonini Alves / Banca: Valtemir Emerencio do Nascimento / Resumo: Quando equipamentos e dispositivos eletrônicos são desenvolvidos, o conhecimento de todas as características do projeto é imprescindível. Certos circuitos eletrônicos apresentam componentes com elevada dissipação térmica devido à potência, podendo acarretar problemas no produto desenvolvido. Os componentes eletrônicos, em sua maioria, apresentam um limite em relação à temperatura, tal propriedade é denominada temperatura de junção, temperatura na qual o die do componente eletrônico se encontra. Se a temperatura de junção for excedida, o componente eletrônico poderá apresentar um comportamento inadequado ou até mesmo a parada total de suas atividades. O ideal é que o projeto elétrico e térmico avancem concomitantemente no desenvolvimento do equipamento, de modo a se obter um produto otimizado. Uma maneira eficiente de avaliar o comportamento térmico dos equipamentos eletrônicos é através de simulações computacionais em softwares de Computational Fluid Dynamics (CFD). O emprego dessa ferramenta não é trivial pela dificuldade da elaboração do modelo numérico. Além disso, alguns valores dos parâmetros necessários do modelo numérico, muitas vezes, não são conhecidos. Um exemplo típico é a potência térmica dissipada dos componentes eletrônicos, não dos elementos passivos como resistores ou capacitores, mas dos circuitos integrados (CIs). Os CIs possuem uma estrutura interna complexa contendo milhares ou até milhões de transistores. Outro exemplo é a placa de circuito impresso (PCI) com vários componentes eletrônicos no seu interior. Neste contexto, esta tese propõe uma metodologia para a obtenção de um modelo numérico correlacionado que pode ser extrapolado para um cenário desejado e a partir deste conhecer o campo de temperatura e de velocidade do equipamento. A metodologia é baseada em uma correlação entre o modelo numérico simplificado e teste... / Abstract: When electronic equipment and devices are developed, the knowledge of all the features of this project is essential. Some electronic circuits have components with high thermal power dissipation, which can cause problems to the product developed. The electronic components have a limit on the temperature, such property is called junction temperature. If the junction temperature is exceeded, the electronic components will display inappropriate behavior or even a complete stop their activities. Ideally, the electrical design and thermal design concurrently advance in the development of the equipment in order to obtain an optimum product. A efficient way to meet the thermal performance of electronic equipment is through computer simulations in Computational Fluid Dynamics (CFD) software. However make use of this tool can be difficult. The difficulty is creating the numerical model. For this procedure is necessary to know some variables that are unknown. The thermal power dissipation of electronic components, not resistors or capacitors, but integrated circuits that has in its interior a very complex structure containing thousands or millions of transistors is an example. The complex structures of the geometries to be modeled that are inside electronic components and PCBs are other examples. In this context, this thesis proposes a methodology based on numerical correlations and experimental tests in order to know the device's temperature range designed running in a desired situation. The methodology is based on a correlation between the simplified numerical model and experimental test. The thermal simulation methodology presented in this thesis brings contributions to the thermal management in the design of electronic equipment. The approach allows doing numerical simulations of equipment for a desired scene and the results assist in project analysis, particularly in reliability and lifetime of electronic ... / Doutor
215

Experimental investigation of a printed circuit heat exchanger using supercritical carbon dioxide and water as heat transfer media

Van Meter, Josh January 1900 (has links)
Master of Science / Department of Mechanical and Nuclear Engineering / Akira T. Tokuhiro / The Secure Transportable Autonomous Reactor – Liquid Metal system combines a Generation IV nuclear reactor with an advanced Supercritical Carbon Dioxide (S-CO[subscript]2) Brayton power conversion cycle. The Brayton cycle was selected as the power conversion cycle due to its high efficiency, small turbomachinery size, and competitive cost due to reduced complexity as compared to a traditional Rankine cycle. Overall system thermal efficiency is closely tied to the performance of the precooler and recuperators. The Printed Circuit Heat Exchanger (PCHE) manufactured by Heatric is being considered for use as both the precooler and recuperator in the STAR-LM system due to its high effectiveness, wide temperature and pressure operating range, small size, and low cost. PCHEs have been used primarily in the hydrocarbon processing industry to date, and are relatively new in being considered for nuclear applications. In this study, a PCHE is investigated using S-CO[subscript]2 and water as the heat transfer media in conditions relevant to the precooler in the STAR-LM system. Experiments conducted with small temperature differences across the PCHE revealed that the heat transfer coefficient is strongly correlated with the temperature-dependent specific heat near the pseudocritical point. The STAR-LM precooler outlet temperature is near the pseudocritical point, making this region of interest to this work. Testing was conducted to determine the effect of property variation near the precooler outlet in conditions with large temperature differences in the PCHE. These tests revealed that maintaining the precooler outlet temperature near the pseudocritical point does not have a significant effect on heat transfer coefficients in the PCHE under large temperature difference test conditions. Computational Fluid Dynamics (CFD) models were developed to simulate fluid flow and heat transfer in the PCHE. A 2D, 4-channel, zig-zag model was found to reproduce the outlet temperatures to within approximately 15% relative error. The 3D straight channel model reproduced the experimental data to within 3% relative error for the cases simulated. Both of these models predicted the water side outlet temperatures to within 20% relative error.
216

CAN BUS USED FOR DATA ACQUISITION SYSTEM CONTROLS (AUTOMOTIVE SOLUTION FOR AIRCRAFT PROBLEM)

Johnson, Bruce, Smith, John 10 1900 (has links)
ITC/USA 2005 Conference Proceedings / The Forty-First Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2005 / Riviera Hotel & Convention Center, Las Vegas, Nevada / This paper discusses using the CAN (Control Area Network) Bus protocol for control and status of flight test data acquisition systems. The application of the CAN (Control Area Network) on an F/A-18 aircraft will be discussed in detail.
217

Inkjet etching of micro-via holes in thin polymer layers

Zhang, Yan January 2014 (has links)
Facilitated by the development of various direct-write techniques and functional polymeric materials including polymer based conductors and semiconductors, printed electronics are flourishing both commercially and as a research topic. This is not only because of their simpler manufacturing routes and lower cost, but also as a result of lower processing temperatures and better compatibility with flexible substrates, compared with conventional electronics. The development of conventional electronics has been guided by Moore s Law, the driver for which lies in the demand for electronic devices with better performance and portability at lower prices. Therefore, one can expect a similar trend for printed electronics to guide its development. Multi-layered printing can be adopted in printed electronics to achieve higher density integration, so that this development trend can be maintained. In such circumstances, creation of electrical connections between multiple layers emerges as an important issue for printed electronics. Inkjet-etched via holes are one potential solution to providing such electrical interconnections, and which can provide good integration with other inkjet-printed features simply by switching nozzles. This thesis aims to elicit a better understanding of the physics involved in inkjet etching and investigate the capability of the inkjet etching technique. In the thesis, the factors that can affect the size of via holes produced by inkjet etching are evaluated, which is significant for evaluating the capability of this technique to deliver industrially relevant features. Identified factors include droplet ejection frequency, droplet diameter, solvent properties and substrate temperature. Droplet ejection frequency, i.e. the reciprocal of the time interval between drops, determines the extent of evaporation of the solvent between two consecutive drop impacts. Droplet diameter determines the radius of the wetted area after the droplet I impacts on the surface and spreads into a sessile drop. Solvents with different evaporation properties result in different size evolution with the number of drops dispensed, as does droplet ejection frequency. Higher substrate temperatures can reduce the drop diameter during flight and decrease the evaporation time on polymer surfaces, which can shrink the size of via holes. Another important issue is achieving complete polymer penetration as residual polymer creates an electrical conduction barrier after such holes are subsequently filled with conductive materials or act as a barrier to filling by electroplating. Experiments have been carried out to test the effect of outer diameter and polymer thickness on polymer penetration. Electroplating is utilised to test the completeness of via hole penetration. A mechanism using the Marangoni effect to explain the protrusion drying pattern other than a hole in the polymer layer is proposed.
218

An overview of chemical waste management of printed circuit board manufacturing in Hong Kong

Kwok, Hon-chiu., 郭漢超. January 1996 (has links)
published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management
219

Development of Test Equipment for Analysis of Camera Vision Systems Used in Car Industry : Printed Ciruit Board Design and Power Distribution Network Stability

Johansson, Jimmy, Odén, Martin January 2015 (has links)
The main purpose of this thesis was to develop a printed circuit board for Autoliv Electronics AB. This circuit board should be placed in their test equipment to support some of their camera vision systems used in cars. The main task was to combine the existing hardware into one module. To be able to achieve this, the most important factors in designing a printed circuit board was considered. A satisfying power distribution network is the most crucial one. This was accomplished by using decoupling capacitors to achieve low enough impedance for all circuits. Calculations and simulations were executed for all integrated circuits to find the correct size and numbers of capacitors. The impedance of the circuit board was tested with a network analyzer to confirm that the impedance were low enough, which was the case. System functionality was never tested completely, due to delivery problems with some external equipment.
220

Chemically Programmed  Memory Card and PC Connected Memory Card Reader

Vadakke Kunninmel, Gokuldev January 2013 (has links)
Inkjet-printed memory cards have been developed previously by re-searchers at Mid Sweden University but, these did possess some limita-tions, as each resistive memory cell required one physical contact and the resistances were designed to be electrically programmed.This work overcomes the above limitations by developing chemically programmed printed memory cards and a PC connected memory card reader. Printed memory cards are inexpensive and are developed by inkjet printing the nano-silver ink onto the photo paper substrate. A matrix readout method is used to increase the num-ber of memory cells and, by using a chemical solvent, the resistances were programmed to the desired resistance values and, for which, each resistance value represents data on the cards, called, write once read many (WORM) memories. The memory card reader was developed to access the data (resistance value) of the memory card and also to trans-mit the data to a LabVIEW graphical user interface for displaying the resistance values. By using multiple resistance steps, in which each step represents a different state, it is possible to create a number of possible selectable combinations which can be programmed at a later stage for developing applications.

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