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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.
51

Virtuální měřicí systém pro nestandardní bezodrazové komory / Virtual Measurement System for the Anechoic Chambers

Váško, Ondřej January 2013 (has links)
Master thesis examines a selected part of electromagnetic compatibility. In this work, there is theoretically discussed how electromagnetic interference appears and how is spread through free space environment. To eliminate ambient interference signals, the measurements have been performed in anechoic chamber where the undesirable interference signals were suppressed. In the thesis, there are also described parameters of EMI receivers and limits of electromagnetic interference. The description of calculations of the antenna height for finding maximum intensity of electric field strength for standard measurement distance has been made. For proposed transformed measurement distance, calculations of intensity electric field with addition of parameters measuring antenna and object under test were performed. Correction curves for conversion intensity electric field have been obtained as the result.
52

Measurement System Analysis : For Battery Production Using DMAIC at Northvolt AB

Nguyen, Phuc, Sahlberg, Adam January 2020 (has links)
As battery manufacturing is enclosed with multiple quality and safety requirements, the batteryindustry needs adequate Measurement Systems (MS) to provide high product quality and ensure a safe working environment. The study purpose was to improve the performance of an MS for battery production by utilizing MSA and Six Sigma methodology, and to make appropriate recommendations for improvement and future control. The study included 28 measurement instruments which were evaluated by the utilization of a framework consisting of five different errors identified in the literature, namely bias, linearity, stability, reproducibility and repeatability. This framework is considered as the theoretical contribution of this study. The improvement methodology DMAIC (Define-Measure-Analyze-Improve-Control) was used to perform the case study. The results indicate an overall improved MS and generated improvement suggestions of three recurrent scenarios that arose in the analysis. Moreover, a company adopted control plan with an intention to serve as a basis for future work within MSA is presented and concerns the practical contribution of this work. The results provide helpful support as well as establish a foundation of how to maintain a well-performing MS for Northvolt. By implementing the suggested recommendations, the potential saving was estimated to 395 000 SEK annually. / En mätsystemanalys genomfördes hos batteritillverkaren Northvolt. Då batteriproduktionomgärdas av flera kvalitets- och säkerhetskrav behöver batteriindustrin tillförlitliga mätsystem för att generera hög produktkvalitet samt upprätthålla en säkerhet för användare. Studien syftade till att förbättra prestandan hos ett mätsystem inom batteriproduktion genom användandet av mätsystemanalys och Sex Sigma-metodik, samt att ge lämpliga rekommendationer för förbättringar och framtida kontroll. Studien inkluderade 28 mätinstrument som utvärderades genom användningen av ett ramverk bestående av fem olika mätsystemfel identifierade i litteraturen, nämligen bias, linearity, stability, reproducibility och repeatability. Detta ramverk betraktas som det teoretiska bidraget från denna studie. Förbättringmetodiken DMAIC (Define-Measure-Analyze-Improve-Control) användes för att utföra fallstudien. Resultaten visar på ett övergripande förbättrat mätsystem och genererade förbättringsförslag på tre återkommande scenarier som uppstod i analysen. Dessutom presenteras en företagsanpassad kontrollplan med avsikt att utgöra en grund för framtida arbete inom mätsystemanalys och ses det praktiska bidraget från denna studie. Resultaten förblir ett användbartstöd samt skapar en grund för hur Northvolt upprätthåller ett högpresterande mätsystem. Genom att säkerställa prestandan av mätsystemet uppskattades den potentiella besparingen till 395 000 SEK årligen.
53

Capacitive Structures for Gas and Biological Sensing

Sapsanis, Christos 04 1900 (has links)
The semiconductor industry was benefited by the advances in technology in the last decades. This fact has an impact on the sensors field, where the simple transducer was evolved into smart miniaturized multi-functional microsystems. However, commercially available gas and biological sensors are mostly bulky, expensive, and power-hungry, which act as obstacles to mass use. The aim of this work is gas and biological sensing using capacitive structures. Capacitive sensors were selected due to its design simplicity, low fabrication cost, and no DC power consumption. In the first part, the dominant structure among interdigitated electrodes (IDEs), fractal curves (Peano and Hilbert) and Archimedean spiral was investigated from capacitance density perspective. The investigation consists of geometrical formula calculations, COMSOL Multiphysics simulations and cleanroom fabrication of the capacitors on a silicon substrate. Moreover, low-cost fabrication on flexible plastic PET substrate was conducted outside cleanroom with rapid prototyping using a maskless laser etching. The second part contains the humidity, Volatile Organic compounds (VOCs) and Ammonia sensing of polymers, Polyimide and Nafion, and metal-organic framework (MOF), Cu(bdc)2.xH2O using IDEs and tested in an automated gas setup for experiment control and data extraction. The last part includes the biological sensing of C - reactive protein (CRP) quantification, which is considered as a biomarker of being prone to cardiac diseases and Bovine serum albumin (BSA) protein quantification, which is used as a reference for quantifying unknown proteins.
54

Wide Area Measurement Applications for Improvement of Power System Protection

Tania, Mutmainna 21 January 2013 (has links)
The increasing demand for electricity over the last few decades has not been followed by adequate growth in electric infrastructure. As a result, the reliability and safety of the electric grids are facing tremendously growing pressure. Large blackouts in the recent past indicate that sustaining system reliability and integrity turns out to be more and more difficult due to reduced transmission capacity margins and increased stress on the system. Due to the heavy loading conditions that occur when the system is under stress, the protection systems are susceptible to mis-operation. It is under such severe situations that the network cannot afford to lose its critical elements like the main generation units and transmission corridors. In addition to the slow but steady variations in the network structure over a long term, the grid also experiences drastic changes during the occurrence of a disturbance. One of the main reasons why protection relays mis-operate is due to the inability of the relays to adjust to the evolving network scenario. Such failures greatly compound the severity of the disturbance, while diminishing network integrity leading to catastrophic system-wide outages. With the advancement of Wide Area Measurement Systems (WAMS), it is now possible to redesign network protection schemes to make them more adaptive and thus improve the security of the system. Often flagged for exacerbating the events leading to a blackout, the back-up distance protection relay scheme for transmission line protection and the loss-of-field relay scheme for generator unit protection can be greatly improved from an adaptability-oriented redesign. Protection schemes in general would benefit from a power re-distribution technique that helps predict generator outputs immediately after the occurrence of a contingency. / Ph. D.
55

Development of a Novel Tool for Assessing Deformation and Hardness of Real Organs: Pressure Measuring Grasper (PMEG) / 生体臓器において力と変形量の関係を測定するための新しい機器:Pressure Measuring Grasper (PMEG) の開発

Sawada, Atsuro 24 November 2016 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第20050号 / 医博第4158号 / 新制||医||1018(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 坂井 義治, 教授 松田 秀一, 教授 安達 泰治 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM
56

Development, Evaluation, and Validation of a High-Resolution Directivity Measurement System for Played Musical Instruments

Bodon, K Joshua 01 March 2016 (has links) (PDF)
A high-resolution directivity measurement system at Brigham Young University has been renovated and upgraded. Acoustical treatments have been installed on the microphone array, professional-grade audio hardware and cabling have been utilized, and user-friendly MATLAB processing and plotting codes have been developed. The directivities of 16 played musical instruments and several loudspeakers have been measured by the system, processed, and plotted. Using loudspeakers as simulated musicians, a comprehensive analysis was completed to validate the system and understand its error bounds. A comparison and evaluation of repeated-capture to single-capture spherical systems was made to demonstrate the high level of detail provided by the 5 degree resolution system. Analysis is undertaken to determine how nonanechoic effects in anechoic chambers influence results. An overview of directivity measurement systems from the literature is provided as well as a dedicated discussion of the directivity measurement system at Brigham Young University.
57

Methods for Validation of a Turbomachinery Rotor Blade Tip Timing System

Pickering, Todd Michael 21 April 2014 (has links)
This research developed two innovative test methods that were used to experimentally evaluate the performance of a novel blade tip timing (BTT) system from Prime Photonics, LC. The research focused on creating known blade tip offsets and tip vibrations so that the results from a BTT system can be validated. The topic of validation is important to the BTT field as the results between many commercial systems still are not consistent. While the system that was tested is still in development and final validation is not complete, the blade tip offset and vibration frequency validation results show that this BTT system will be a valuable addition to turbomachinery research and development programs once completed. For the first test method custom rotors were created with specified blade tip offsets. For the blade tip offset alternate measurement, the rotors were optically scanned and analyzed in CAD software with a tip location uncertainty of 0.1 mm. The BTT system agreed with the scanned results to within 0.13 mm. Tests were also conducted to ensure that the BTT system identified and indexed the blades properly. The second developed test method used an instrumented piezoelectric blade to create known dynamic deflections. The active vibration rotor was able to create measureable deflection over a range of frequencies centered on the first bending mode of the blade. The results for the 110 Hz, 150 Hz, 180 Hz first bending resonance, 200 Hz, and 1036 Hz second bending resonance cases are presented. A strain gage and piezoelectric sensor were attached to the active blade during the dynamic deflection tests to provide an alternate method for determining blade vibration frequency. The BTT system correctly identified the active blade excitation frequencies as well as a 120 Hz frequency from the drive motor. This thesis also explored applying BTT methods and testing to more realistic blade geometry and vibration. Blade vibrations are usually classified by their frequency relative to the rotation speed. Synchronous vibrations are integer multiples of the rotational speed and are often excited by struts or vanes fixed to the engine case. For this reason, special probe placement algorithms were explored that use sine curve fitting to optimize the probe placement. Knowing how the blade will vibrate at operation before testing is critical as well. In preparation for future research, ANSYS Mechanical was used to predict the first three modes of a PT6A-28 first stage rotor blade at 1,966, 5,539, and 7,144 Hz. These frequencies were validated to within 4% using scanning laser vibrometry. The simulation was repeated at speed to produce a Campbell Diagram to highlight synchronous excitation crossings. / Master of Science
58

Performance measurement system for a manufacturing environment: KB/GAP/AHP approach

Wibisono, D., Khan, M. Khurshid 27 December 2015 (has links)
Yes / Designing and implementing Performance Measurement System (PMS) is an integral part of management control systems. This paper presents an original and novel approach to designing and benchmarking of PMSs for a manufacturing environment through a hybrid framework which overcomes the shortcomings of earlier models. A detailed review was taken of previous models and their limitations were identified. The present hybrid PMS model seeks to improve the earlier research models by the following novel approach: implementation of a Knowledge Based (KB) expert system, Gauging Absences of Pre-requisite (GAP) analysis and Analytic Hierarchy Process (AHP) methodology in an integrated KBPMS. The paper has shown that the present hybrid (KB-AHP-GAP) approach to developing a KBPMS model is a realistic methodology. The combination of the KB-AHP-GAP approach allows detailed benchmarking of the PMS existing within a manufacturing organisation. Furthermore, this approach can assist in identifying and prioritising the key decisions that need to be actioned to overcome the existing PMS shortcomings.
59

Experimental and theoretical analysis of the buried corrugated plastic pipe

Liu, Xuegang January 1993 (has links)
No description available.
60

Exploring the Impact of Top-Management Teams over Management Control System Design and Use / マネジメント・コントロール・システムの設計と利用方法に対してトップマネジメント・チームが与える影響の探索

Mohamed, Mahmoud Mohamed Ahmed 24 September 2021 (has links)
京都大学 / 新制・課程博士 / 博士(経済学) / 甲第23446号 / 経博第644号 / 新制||経||299(附属図書館) / 京都大学大学院経済学研究科経済学専攻 / (主査)教授 澤邉 紀生, 教授 草野 真樹 講師 鈴木 寛之 / 学位規則第4条第1項該当 / Doctor of Economics / Kyoto University / DGAM

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