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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.
41

Reliable On Board Data Processing System for the ICEYE- 1 satellite

Korczyk, Jakub January 2016 (has links)
Recent development in electronics for mobile devices has led to the decrease in sizes and cost of autonomous complex embedded systems such as satellites. It is now possible to build a satellite quicker and only for a fraction of previous costs by using Commercial Off The Shelf (COTS) components. Yet, there are some obstacles that need to be overcome before a successful small satellite can be designed. Among these are the radiation environment, thermal issues, the overall system complexity and tight schedules. This thesis addresses these issues and proposes an overall approach for designing small satellites’ electronics. This approach can be summarised in 6 recommendations: Keep it simple Use fast hardware iterations Do not use space grade components Use a single string design on the system level (no redundancy) Design with limited trust in the software Use simple, accessible and easy updatable documentation With respect to those recommendations an on board data processing system, the Processing Board, has been designed for the ICEYE-1 satellite. The ICEYE-1 satellite is a fully commercial Synthetic Aperture Radar (SAR) satellite that will be launched in December 2017. The designed board has been manufactured and verified during airborne test campaigns. / Nya elektronikutvecklingar för mobiltelefoner har lett till en minskning av storlek och kostnader för andra autonoma komplexa inbyggda system som t.ex. satelliter. Så kallade småsatelliter kan numera byggas snabbare och för endast en bråkdel av tidigare kostnader med hjälp av Commercial Off The Shelf (COTS) komponenter. Det finns dock vissa hinder som måste övervinnas om man vill designa en pålitligt fungerande småsatellit. Till dessa kan räknas strålningsmiljön, väl fungerande värmeledning, det totala systemets komplexitet samt snäva tidtabeller. Detta examensarbete behandlar dessa frågor och föreslår en övergripande strategi för att designa elektronik för småsatelliter. Detta tillvägagångssätt kan sammanfattas i 6 rekommendationer: Håll det enkelt Implementera snabba hårdvaruiterationer Använd inte rymdklassade komponenter Använd ingen redundans på systemnivå Designa med en begränsad tilltro på mjukvaran Dokumentera på ett enkelt, tillgängligt och lätt uppdateringsbart sätt Dessa rekommendationer har använts till att utveckla ett databehandlingssystem, kallat "Processing Board", till småsatelliten ICEYE-1. ICEYE-1 är en kommersiell Synthetic Aperture Radar (SAR) satellit som kommer att skjutas i omloppsbana i december 2017. Databehandlingssystemet i fråga har utvecklats och verifierats i samband med flygplansburna testkampanjer.
42

Application of Lamb waves using piezoelectric technique for structure health monitoring / Tillämpning av Lambvågor med hjälp av piezoelektrisk teknik för strukturhälsoövervakning

Mauritz, Simon January 2023 (has links)
Structural health monitoring (SHM) is damage detection strategy for aerospace, civiland mechanical infrastructure. This project tries to show that Lamb waves, that are being generated and sensed with piezoelectric transducers, can be used for damage detection in a SHM system. For these piezoelectric transducers to work, filtering and amplification circuits needs to be connected to them. This report include the design,simulation, assembly and testing of these circuits. Due to lack of time, it was not possible to generate and sense actual Lamb waves. The result of the thesis is thatsimulations and tests show that it is possible to generate and sense Lamb waves for damage detection in a SHM system / Structural health monitoring (SHM) är en skadedetekteringsstrategi för flyg-,civil- och mekanisk infrastruktur. Detta projekt försöker visa att Lambvågor, som genereras och avkänns med piezoelektriska givare, kan användas för skadedetektering i ett SHM-system. För att dessa piezoelektriska givare ska fungera krävs att filtrerings- och förstärkningskretsar är anslutna till dem. Denna rapport inkluderar design, simulering, montering och testning av dessa kretsar. På grund av tidsbrist var det inte möjligt att generera eller avkänna Lambvågor. Resultatet av examensarbetet är att simuleringar och tester visar att det är möjligt att generera och avkänna Lambvågor för skadedetektering i ett SHM-system.
43

Design of a channel board used in an electronic warfare target simulator

Andersson, Peter January 2006 (has links)
<p>A channel board was designed for a DRFM circuit. The DRFM is implemented in a Virtex-4 FPGA from Xilinx. In the future a similar channel board is intended to be used for target echo generation in ELSI which is an electronic warfare simulator at Saab Bofors Dynamics in Linköping.</p><p>Besides the DRFM circuit the channel board consists of analog-to-digital converters, digital-to-analog converters, Ethernet plug-in board with a microcontroller, voltage regulators, FPGA configuration memory, voltage amplifiers, current amplifiers, oscillator, buffers/drivers and bus transceivers. The sample rate is 200 MHz and LVDS signalling standard is used between the DRFM circuit and the converters.</p><p>The channel board has a JTAG interface which enables in-system programming of the FPGA. This implies that the DRFM can easily be redesigned. An external computer can manage the channel board via Ethernet. Software was developed for the microcontroller on the channel board and for the external computer. The function of the channel board is heavily dependent on the DRFM circuit.</p><p>The channel board design resulted in the assembly of a prototype circuit board. Measurements were performed in a lab and the channel board was approved to be integrated in ELSI for further tests.</p>
44

Design of a Highly Constrained Test System for a 12-bit, 16-channel Wilkinson ADC

Pannell, Zachary William 01 December 2009 (has links)
Outer space is a very harsh environment that can cause electronics to not operate as they were originally intended. Aside from the extreme amount of radiation found in space, temperatures can also change very dramatically in a relatively small time frame. In order to test electronics that will be used in this environment, they first need to be tested on Earth under replicated conditions. Vanderbilt University designed a dewar that allows devices to be tested at these extreme temperatures while being radiated. For this thesis, a test setup that met all of the dewar's constraints was designed that would allow a 12-bit, 16-channel analog-to-digital converter to be tested while inside.
45

Heterogeneous Technologies for Microfluidic Systems

Sharma, Gunjana January 2010 (has links)
In this thesis, conventional and unconventional technologies have been studied and combined in order to make heterogeneous microfluidics with potential advantages, especially in biological applications. Many conventional materials, like silicon, glass, thermoplastic polymers, polyimide and polydimethylsiloxane (PDMS) have been combined in building heterogeneous microfluidic devices or demonstrators. Aside from these materials, unconventional materials for microfluidics such as stainless steel and the fluoroelastomer Viton have been explored. The advantages of the heterogeneous technologies presented were demonstrated in several examples: (1) For instance, in cell biology, surface properties play an important role. Different functions were achieved by combining microengineering and surface modification. Two examples were made by depositing a Teflon-like film: a) a non-textured surface was made hydrophobic to allow higher pressures for cell migration studies and b) a surface textured by ion track technology was even made super-hydrophobic. (2) In microfluidics, microactuators used for fluid handling are important, e.g. in valves and pumps. Here, microactuators that can handle high-pressures were presented, which may allow miniaturization of high performance bioanalyses that until now have been restricted to larger instruments. (3) In some applications the elastomer PDMS cannot be used due to its high permeability and poor solvent resistivity. Viton can be a good replacement when elasticity is needed, like in the demonstrated paraffin actuated membrane.(4) Sensing of bio-molecules in aquatic solutions has potential in diagnostics on-site. A proof-of-principle demonstration of a potentially highly sensitive biosensor was made by integrating a robust solidly mounted resonator in a PDMS based microfluidic system. It is concluded that heterogeneous technologies are important for microfluidic systems like micro total analysis systems (µTAS) and lab-on-chip (LOC) devices.
46

Design of a channel board used in an electronic warfare target simulator

Andersson, Peter January 2006 (has links)
A channel board was designed for a DRFM circuit. The DRFM is implemented in a Virtex-4 FPGA from Xilinx. In the future a similar channel board is intended to be used for target echo generation in ELSI which is an electronic warfare simulator at Saab Bofors Dynamics in Linköping. Besides the DRFM circuit the channel board consists of analog-to-digital converters, digital-to-analog converters, Ethernet plug-in board with a microcontroller, voltage regulators, FPGA configuration memory, voltage amplifiers, current amplifiers, oscillator, buffers/drivers and bus transceivers. The sample rate is 200 MHz and LVDS signalling standard is used between the DRFM circuit and the converters. The channel board has a JTAG interface which enables in-system programming of the FPGA. This implies that the DRFM can easily be redesigned. An external computer can manage the channel board via Ethernet. Software was developed for the microcontroller on the channel board and for the external computer. The function of the channel board is heavily dependent on the DRFM circuit. The channel board design resulted in the assembly of a prototype circuit board. Measurements were performed in a lab and the channel board was approved to be integrated in ELSI for further tests.
47

The Information Architecture Model Supporting Global Logistics Strategy : A Case Study on the Printed Circuit Board Industry of Taiwan

Su, Sheng-I 10 August 2006 (has links)
Under the competitive situation of globalization, the competition and challenges that the enterprises are confronting now are more rigorous than in the past. The PCB industries in Taiwan had ever ranked the third biggest in the world. However, on account of the shifting of the manufacturing bases in the worldwide, in 2002 the PCB output value in China had taken the place of Taiwan and become the third biggest in the world. And in the course of PCB industry development in China, the PCB enterprises from Taiwan had also participated in it early or late. The main inducing reasons were because of the undeveloped markets, low labor and land cost. When the arising of new and developing markets has made the scale of the enterprises expand from the arrangement of single area (Taiwan) into regional areas (Asia), the management range of the enterprise has also expanded at the same time and the management and cost problems it derived and the related problems caused by the management risks due to obscure information will be coming up. Therefore, how to connect the nerve center of the enterprise with each subsidiary, logistic warehouses, customers and suppliers of the group and integrate and set up the information network of upper and lower reaching customers and manufacturers and subsidiary and establish a set of mode suitable for the implement of information plans of the group and for the organization management so as to achieve the goals of fast information obtaining, policy making and real-time reaction and enable the overall arrangement of globalization to elaborate multiple effects, which is the purpose of the study. The study has analyzed the management of supply chain, the global planning and management mode and the application and development of information technology and also proceeded extensive analysis and research from the industrial structure, characteristics of PCB and its future competition superiority. Under the information goal of enhancing enterprise¡¦s competition superiority, the study has proposed related suggestions from the organization and management dimensions and information technology and application support dimension. 1. On the organization dimension and the plan of organization functions, achieve centralized planning so as to conform to the company¡¦s overall biggest profits; to maintain and implement of the subsidiary in each area to conform to the effects of localization and discrepancy; to avoid excessive centralized management which will cause the ineffectiveness of operation in each subsidiary or the excessive independence of the area which will cause the difficulties of the overall information establishment standardization and integration. Therefore, in addition to the original vertical framework, it has increased the planning of investigation organization functions (horizontal organization) so as to assist to help with the management and operation among between multi-site companies. 2. On the management dimension, it has developed modes from information system according to five stages of work: (1) the system planning stage (2) the system analysis stage (3) the system development stage (4) the conduction stage of system duplication and (5) system maintenance stage to scheme discussion topics like multi-area resources integration, multi-area coordinated collaboration system and multi-area rights and duties of labor division to be developed into an information construction management mode. 3. On the dimension of information technology and application support, according to the trade object and trade conduct of the enterprise, it has advanced the framework o f enterprise¡¦s information operation strategy and logistics management. Besides, it has conferred the framework of the information integration according to the aspect of resources sharing among the group¡¦s subsidiary so as to achieve the goals of supporting enterprise¡¦s strategy development and management optimization. Eventually it has proposed the blueprint of PCB industry system construction, the steps of system construction, and the constructional labor division mode of information among regional subsidiary of the group to be offered for the trade to refer to this framework under such global operation strategy and logistics management to develop the information system of supporting the enterprise¡¦s core competition superiority.
48

Catalytic Wet Air Oxidation of the High-concentration (COD) Wastewater Generated from the Printed Circuit Board Industry

Lin, Shyh-Liang 21 July 2000 (has links)
In this study, the wastewater generated from etching process of the Printed Circuit Board (PCB) was treated by a process including both acidification and coagulation/sedimentation and then followed by the catalytic wet air oxidation (CWAO) over different catalysts (either Pt/SiO2¡PAl2O3 or Pt¡PX/£^-Al2O3) process in series. Although the initial chemical oxygen demand (COD) concentration of the wastewater is as high as 7740-12700 mg/L, the effluent of the pretreatment process was measured to have COD value in ranges of 3050-4260 mg/L. Several re-action parameters, such as reaction temperatures (200-260¢J), oxygen partial pressures (0-3 MPa), and two kinds of catalysts were performed experimentally to investigate the COD reduction of the wastewater during the CWAO process. Both reaction temperature and variety of catalyst are found most effectively on the COD reduction. However, the effect of oxygen partial pressure on the COD reduction is just in little. Results showed that the COD reduction during the CWAO over the Pt¡PX/£^-Al2O3 catalyst process is the most significant, which with a tow-step re-action and both the two reactions do obey first-order reaction kinetics. A change from a higher reaction activity of the CWAO reaction to a slower one implies a decrease of the reaction rate. On basis of our experiments data, the effective operating conditions of CWAO for the COD reduction was observed to be at temperature of 260¢J under oxygen partial pressure of 2.0 MPa and at a retention time period of 60 min. The COD conversion was calculated as high as 75%; however, it could be enhanced up to 78% and 91%, respectively, when the CWAO was conducted in presence of the Pt/SiO2¡PAl2O3 and Pt¡PX/£^-Al2O3 catalysts, respectively. It can be seen that the organic compound of the wastewater was mineralized most completely (with a COD/TOC ratio of 3.7¡Ó0.2) after the CWAO over the Pt¡PX/£^-Al2O3 catalyst process. Furthermore, a higher COD/TOC ratio of 3.9¡Ó0.3 was achieved when the Pt/SiO2¡PAl2O3 catalyst was in presence of the CWAO process, and the primitive WAO process had the highest COD/TOC ratio of 4.8¡Ó0.4. The experimental data showed that both a higher reaction temperature (¡Ù260¢J) and an application of catalyst are more important factors for the min-eralization of the organic compound of the wastewater during the CWAO process. In our investigation, BOD5/COD ratio has been used to assess if the WAO and/or the CWAO process treatment yield products more amenable to biodegradation. The BOD5/COD ratio was 0.68-0.93 when the reaction temperature was above 220¢J and the retention time was as long as 60 min. Unfortunately, the BOD5/COD ratio of the effluent from the CWAO process came out a lower value (0.45-0.65) though it was under the same reaction conditions. It is probable that the biodegradable portion of the organic compounds of the wastewater were decomposed easier during the CWAO process than during the WAO process. In addition, it was found that the products of the wastewater was decomposed partially into CO2 and into some low molecular weigh acids, such as formic acid, acetic acid, propionic acid, etc. The activation energy with respect to COD was calculated to be 38.42 kJ/mole and 83 kJ/mole, respectively, for the first-step reaction and for the second-step reaction, respectively, of the WAO process. It was al-so calculated that the first-step reaction of the CWAO over the Pt/SiO2¡PAl2O3 catalyst process has activation energy of 18.25 kJ/mole and 25.76 kJ/mole is for the second-step reaction. However, 16.05 kJ/mole and 49.61 kJ/mole are calculated for the first-step and the sec-ond-step reactions, respectively, of the CWAO over the Pt¡PX/£^-Al2O3 catalyst process. It can be seen that the application of both the Pt/SiO2¡PAl2O3 and the Pt¡PX/£^-Al2O3 catalysts has a significant effect on reducing the activation energy of the WAO. It was observed that the total COD conversion of the wastewater is as high as 96% and the BOD5/COD ratio of the effluent has been en-hanced up to more than 0.6. The combination of both the CWAO over the Pt¡PX/£^-Al2O3 catalyst and the biological treatment is a promising tech-nique for the PCB¡¦s wastewater treatment to fit the wastewater control regulation in Taiwan, which requests the COD value of the wastewater discharged should be less than 120 mg/L.
49

Design of a Highly Constrained Test System for a 12-bit, 16-channel Wilkinson ADC

Pannell, Zachary William 01 December 2009 (has links)
Outer space is a very harsh environment that can cause electronics to not operate as they were originally intended. Aside from the extreme amount of radiation found in space, temperatures can also change very dramatically in a relatively small time frame. In order to test electronics that will be used in this environment, they first need to be tested on Earth under replicated conditions. Vanderbilt University designed a dewar that allows devices to be tested at these extreme temperatures while being radiated. For this thesis, a test setup that met all of the dewar's constraints was designed that would allow a 12-bit, 16-channel analog-to-digital converter to be tested while inside.
50

Materials Selection and Processing Techniques for Small Spacecraft Solar Cell Arrays

Torabi, Naseem M. 01 January 2013 (has links)
Body mounted germanium substrate solar cell arrays form the faces of many small satellite designs to provide the primary power source on orbit. High efficiency solar cells are made affordable for university satellite programs as triangular devices trimmed from wafer scale solar cells. The smaller cells allow array designs to pack tightly around antenna mounts and payload instruments, giving the board design flexibility. One objective of this work is to investigate the reliability of solar cells attached to FR-4 printed circuit boards. FR-4 circuit boards have significantly higher thermal expansion coefficients and lower thermal conductivities than germanium. This thermal expansion coefficient mismatch between the FR-4 board and the components causes concern for the power system in terms of failures seen by the solar cells. These failures are most likely to occur with a longer orbital lifetime and an extended exposure to harsh environments. This work compares various methods of attaching solar cells to printed circuit boards, using solder paste alone and with a silicone adhesive, and considering the application of these adhesives by comparing the solder joints when printed by screen versus a stencil. An environmental test plan was used to compare the survivability and performance of the solar arrays.

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