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Modeling and Verification of Simulation tools for Carburizing and CarbonitridingZhang, Lei 31 May 2017 (has links)
"The CHTE surface hardening simulation tools, CarboNitrideTool© and CarbTool© have been enhanced to improve the accuracy of the simulation and to predict the microstructure and microhardness profiles after the heat treatment process. These tools can be used for the prediction of both gas and low pressure carburizing processes. The steel alloys in the data base include 10XX, 48XX, 51XX, 86XX, 93XX and Pyrowear 53. They have been used by CHTE members to design efficient carburizing cycles to maximum the profit by controlling the cost and time. In the current software, the model has successfully predicted the carbon concentration profiles for gas carburizing process and many low pressure carburizing processes. In some case, the simulation toll may not work well with the low pressure carburizing process, especially with AISI 9310 alloy. In the previous simulation, a constant carbon flux boundary condition was used. However, it has been experimentally proven that the flux is a function of time. The high carbon potential may cause soot and carbides at the outer edge. The soot and carbides will impede the diffusion of carbon during the low pressure carburizing process. The constant carbon flux cannot be appropriately used as the boundary condition. An improved model for the process is proposed. In the modeling, carbon potential and mass transfer coefficient are calculated and used as the boundary condition. CarbonitrideToolⒸ has been developed for the prediction of both carbon and nitrogen profiles for carbonitriding process. The microstructure and hardness profile is also needed by the industry. The nitrogen is an austenite stabilizer which result in high amount of retained austenite (RA). RA plays important role in the hardness. The model has been developed to predict the Martensite start temperature (Ms) which can be used for RA prediction. Mixture rule is used then to predict the hardness profiles. Experiments has been conducted to verify the simulation. The hardness profile is also predicted for tempered carburized alloys. Hollomon-Jaffe equation was used. A matrix of tempering experiments are conducted to study the Hollomon Jaffe parameter for AISI 8620 and AISI 9310 alloy. Constant C value is calculated with a new mathematical method. With the calculation result, the hardness profile can be predicted with input of tempering time and temperature. Case depth and surface hardness are important properties for carburized steel that must be well controlled. The traditional testing is usually destructive. Samples are sectioned and measured by either OES or microhardness tester. It is time consuming and can only be applied on sampled parts. The heat treating industry needs a physics based, verified simulation tool for surface hardening processes to accurately predict concentration profiles, microstructure and microhardness profiles. There is also a need for non-destructive measurement tool to accurately determine the surface hardness and case depth. Magnetic Barkhausen Noise (MBN) is one of the promising way to test the case depth and hardness. MBN measures the pulses generating by the interaction between magnetic domain walls in the ferromagnetic material and the pinning sites such as carbides, impurities and dislocation. These signals are analyzed to evaluate the properties of the carburized steel. "
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The Use of Equalization Filters to Achieve High Common Mode Rejection Ratios in Biopotential Amplifier ArraysXia, Hongfang 12 May 2005 (has links)
Recently, it became possible to detect single motor units (MUs) noninvasively via the use of spatial filtering electrode arrays. With these arrays, weighted combinations of monopolar electrode signals recorded from the skin surface provide spatial selectivity of the underlying electrical activity. Common spatial filters include the bipolar electrode, the longitude double differentiating (LDD) filter and the normal double differentiating (NDD) filter. In general, the spatial filtering is implemented in hardware and the performance of the spatial filtering apparatus is measured by its common mode rejection ratio (CMRR). High precision hardware differential amplifiers are used to perform the channel weighting in order to achieve high CMRR. But, this hardware is expensive and all channel weightings must be predetermined. Hence, only a few spatially filtered channels are typically derived. In this project, a distinct software equalization filter was cascaded with each of the hardware monopolar signal conditioning circuits to achieve accurate weighting and high CMRR. The simplest technique we explored was to design an equalization filter by dividing the frequency response of a“reference" (or“ideal") channel by the measured frequency response of the channel being equalized, producing the desired equalization filter in the frequency domain (conventional technique). Simulation and experimental results showed that the conventional technique is very sensitive to broadband background noise, producing poor CMRR. Thus, a technique for signal denoising that is based on signal mixing was pursued and evaluated both in simulation and laboratory experiments. The purpose of the mixing technique is to eliminate the noise as much as possible prior to equalization filter design. The simulation results show that without software equalization, CMRR is only around 30 dB; with conventional technique CMRR is around 50~60 dB. By using mixing technique, CMRR can be around 70~80 dB.
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Pintura, silêncio e outros ruídos / -Thiago Dall\'Aglio Hattnher 05 October 2018 (has links)
A dissertação Pintura, silêncio e outros ruídos tem como principal mirada reflexiva a produção de dois artistas norte-americanos: John Cage e Cy Twombly. Partindo das proposições de entendimento do conceito de silêncio feitas por John Cage, Pintura, silêncio e outros Ruídos tensiona algumas aproximações entre determinados trabalhos de Cage - produzidos a partir de 4\'33, 1952 - e da produção em pintura e desenho de Twombly, sugerindo algumas relações entre som, desenho, pintura e ruído. As reflexões geradas a partir da aproximação entre os dois artistas são levadas, em seguida, à minha própria produção em pintura, observando a maneira como incidem em minha investigação prática. / The dissertation Painting, silence and other noises has as its main focus of reflection the work of two north-american artist: John Cage and Cy Twombly. Following along the understanding propositions of the concept of silence done by John Cage, Painting, silence and other stresses some similarities between some (specific) work done by Cage - fr 4\'33? and beyond - and both pantings and drawings by Twombly, suggesting some relationship between sound, drawing, painting and noise. The reflections generated from the proximity between the two artists are considered, as follows, in my own production of paintings, noting how they influence my own research.
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New data on noise visibility and its application to image transmissionMalone, Ulick Oliver January 1977 (has links)
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1977. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by Ulick Oliver Malone. / M.S.
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Arctic Ocean ambient noise.Shepard, George Woods January 1979 (has links)
Thesis (Ocean E)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1979. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaves 178-180. / Ocean E
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Piston slap noise in diesel enginesSlack, James W January 1982 (has links)
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by James W. Slack. / Ph.D.
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An experimental study of windturbine noiseMarcus, Edward N January 1982 (has links)
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1982. / Microfiche copy available in Archives and Barker / Includes bibliographical references. / by Edward N. Marcus. / M.S.
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Flow generated noise of acoustical duct liners.Hrubes, James Dana January 1977 (has links)
Thesis. 1977. M.S.--Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND AERO. / Includes bibliographical references. / M.S.
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A low-frequency instability mechanism in a coaxial dump combustorKeklak, John Adam January 1982 (has links)
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by John Adam Keklak. / M.S.
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CMOS RF low noise amplifier with high ESD immunity.January 2004 (has links)
Tang Siu Kei. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 107-111). / Abstracts in English and Chinese. / Acknowledgements --- p.ii / Abstract --- p.iii / List of Figures --- p.xi / List of Tables --- p.xvi / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Overview of Electrostatic Discharge --- p.1 / Chapter 1.1.1 --- Classification of Electrostatic Discharge Models --- p.1 / Chapter 1.2 --- Electrostatic Discharge in CMOS RF Circuits --- p.4 / Chapter 1.3 --- Research Goal and Contribution --- p.6 / Chapter 1.4 --- Thesis Outline --- p.6 / Chapter Chapter 2 --- Performance Parameters of Amplifier --- p.8 / Chapter 2.1 --- Amplifier Gain --- p.8 / Chapter 2.2 --- Noise Factor --- p.9 / Chapter 2.3 --- Linearity --- p.11 / Chapter 2.3.1 --- 1-dB Compression Point --- p.13 / Chapter 2.3.2 --- Third-Order Intercept Point --- p.14 / Chapter 2.4 --- Return Loss --- p.16 / Chapter 2.5 --- Power Consumption --- p.18 / Chapter 2.6 --- HBM ESD Withstand Voltage --- p.19 / Chapter Chapter 3 --- ESD Protection Methodology for Low Noise Amplifier --- p.21 / Chapter 3.1 --- Dual-Diode Circuitry --- p.22 / Chapter 3.1.1 --- Working Principle --- p.22 / Chapter 3.1.2 --- Drawbacks --- p.24 / Chapter 3.2 --- Shunt-Inductor Method --- p.25 / Chapter 3.2.1 --- Working Principle --- p.25 / Chapter 3.2.2 --- Drawbacks --- p.27 / Chapter 3.3 --- Common-Gate Input Stage Method --- p.28 / Chapter 3.3.1 --- Built-in ESD Protecting Mechanism --- p.29 / Chapter 3.3.2 --- Competitiveness --- p.31 / Chapter Chapter 4 --- Design Theory of Low Noise Amplifier --- p.32 / Chapter 4.1 --- Small-Signal Modeling --- p.33 / Chapter 4.2 --- Method of Input Termination --- p.33 / Chapter 4.2.1 --- Resistive Termination --- p.34 / Chapter 4.2.2 --- Shunt-Series Feedback --- p.34 / Chapter 4.2.3 --- l/gm Termination --- p.35 / Chapter 4.2.4 --- Inductive Source Degeneration --- p.36 / Chapter 4.3 --- Method of Gain Enhancement --- p.38 / Chapter 4.3.1 --- Tuned Amplifier --- p.38 / Chapter 4.3.2 --- Multistage Amplifier --- p.40 / Chapter 4.4 --- Improvement of Reverse Isolation --- p.41 / Chapter 4.4.1 --- Common-Gate Amplifier --- p.41 / Chapter 4.4.2 --- Cascoded Amplifier --- p.42 / Chapter Chapter 5 --- Noise Analysis of Low Noise Amplifier --- p.44 / Chapter 5.1 --- Noise Sources of MOS Transistor --- p.44 / Chapter 5.2 --- Noise Calculation using Noisy Two-Port Network --- p.46 / Chapter 5.3 --- Noise Calculation using Small-Signal Model --- p.49 / Chapter 5.3.1 --- Low Noise Amplifier with Inductive Source Degeneration --- p.49 / Chapter 5.3.2 --- Common-Gate Low Noise Amplifier --- p.52 / Chapter Chapter 6 --- Design of an ESD-protected CMOS Low Noise Amplifier --- p.54 / Chapter 6.1 --- Design of DC Biasing Circuitry --- p.55 / Chapter 6.2 --- Design of Two-Stage Architecture --- p.57 / Chapter 8.3.1 --- Design of Common-Gate Input Stage --- p.57 / Chapter 8.3.2 --- Design of Second-Stage Amplifier --- p.59 / Chapter 6.3 --- Stability Consideration --- p.61 / Chapter 6.4 --- Design of Matching Networks --- p.62 / Chapter 6.4.1 --- Design of Inter-Stage Matching Network --- p.64 / Chapter 6.4.2 --- Design of Input and Output Matching Networks --- p.67 / Chapter Chapter 7 --- Layout Considerations --- p.70 / Chapter 7.1 --- MOS Transistor --- p.70 / Chapter 7.2 --- Capacitor --- p.72 / Chapter 7.3 --- Spiral Inductor --- p.74 / Chapter 7.4 --- Layout of the Proposed Low Noise Amplifier --- p.76 / Chapter 7.5 --- Layout of the Common-Source Low Noise Amplifier --- p.79 / Chapter 7.6 --- Comparison between Schematic and Post-Layout Simulation Results --- p.81 / Chapter Chapter 8 --- Measurement Results --- p.82 / Chapter 8.1 --- Experimental Setup --- p.82 / Chapter 8.1.1 --- Testing Circuit Board --- p.83 / Chapter 8.1.2 --- Experimental Setup for s-parameter --- p.84 / Chapter 8.1.3 --- Experimental Setup for Noise Figure --- p.84 / Chapter 8.1.4 --- Experimental Setup for 1-dB Compression Point --- p.85 / Chapter 8.1.5 --- Experimental Setup for Third-Order Intercept Point --- p.86 / Chapter 8.1.6 --- Setup for HBM ESD Test --- p.87 / Chapter 8.2 --- Measurement Results of the Proposed Low Noise Amplifier --- p.89 / Chapter 8.2.1 --- S-parameter Measurement --- p.90 / Chapter 8.2.2 --- Noise Figure Measurement --- p.91 / Chapter 8.2.3 --- Measurement of 1-dB Compression Point --- p.92 / Chapter 8.2.4 --- Measurement of Third-Order Intercept Point --- p.93 / Chapter 8.2.5 --- HBM ESD Test --- p.94 / Chapter 8.2.6 --- Summary of Measurement Results --- p.95 / Chapter 8.3 --- Measurement Results of the Common-Source Low Noise Amplifier --- p.96 / Chapter 8.3.1 --- s-parameter Measurement --- p.97 / Chapter 8.3.2 --- Noise Figure Measurement --- p.98 / Chapter 8.3.3 --- Measurement of 1-dB Compression Point --- p.99 / Chapter 8.3.4 --- Measurement of Third-Order Intercept Point --- p.100 / Chapter 8.3.5 --- HBM ESD Test --- p.101 / Chapter 8.3.6 --- Summary of Measurement Results --- p.102 / Chapter 8.4 --- Performance Comparison between Different Low Noise Amplifier Designs --- p.103 / Chapter Chapter 9 --- Conclusion and Future Work --- p.105 / Chapter 9.1 --- Conclusion --- p.105 / Chapter 9.2 --- Future Work --- p.106 / References --- p.107 / Author's Publications --- p.112
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