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Boehm, Kevin (Kevin W. ). "An improved visualization of diesel particulate filter/." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/69502.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (p. 39).<br>The prevalence of diesel particulate filters (DPF) is increasing as emissions standards worldwide evolve to match current technologies. Since the first application of DPFs in the 1980's, PM trapping effectiveness has increased by orders of magnitude. During the filter's use phase, it is subject to multiple cycles of particulate matter trapping and regeneration. The soot particles are combusted in the high temperatures; however, metal additives referred to as ash, primarily from lubricants, remain behind and restrict exhaust flow. Further ash accumulation causes a pressure drop across the filter and necessitates replacement in order to maintain fuel economy and engine performance. Research into more efficient DPF designs and geometries examines current limitations with the goal of emitting cleaning emissions and extending DPF use. In order to gain a better understanding of PM trapping and regeneration and acquire real-time feedback, an improved visualization method of DPF is required. For that method, powder glass frit was applied between the filter and glass window and heated to form a bond. After the heating process, the bond strength was measured to determine optimal heating cycles and surface conditions for the glass seal. The experimental results were examined to measure the success of the bonding method relative to previous research using alternative methods. The ability to test and observe ash accumulation in different DPF designs will contribute to the understanding of PM trapping.<br>by Kevin Boehm.<br>S.B.
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Stancil, Byron Miguel 1976. "Design of a programmable filter for macromolecules." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/89371.
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Lipson, Ariel. "A tunable micro-electro-mechanical optical filter in silicon." Thesis, Imperial College London, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.441291.
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Walter, Sandra L. "Optimizing the efficiency and filter area of the SurgiBox Environmental System by redistributing effective media area across filter length." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/127866.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, May, 2020<br>Cataloged from the official PDF of thesis.<br>Includes bibliographical references (page 46).<br>Across the globe, billions of people lack access to safe surgery. SurgiBox is working to lower that number by creating a portable surgical environment for patients in need. To do this, they are working to improve their air filtration system by better utilizing filter media to create a more efficient system. To help SurgiBox achieve this goal, Solidworks Flow Simulation Models were created and analysed to determine what parameters would be necessary to achieve a goal of a uniform velocity profile while meeting volumetric flow rate specifications. These models show that it is possible to achieve a uniform velocity distribution by using filters with varied resistances to air flow. It was found that, neglecting edge effects, the pressure drops (at a defined velocity) of the filter follow a linear trend across the length of the filter. However, these models also show that edge effects lead to significant air flow inconsistencies revealing that if these edge effects are not addressed, the system may quickly fall out of specification. Numerically generated "ideal" system centerline velocity and pressure curves were created to be used as comparative tools while conducting experiments on the SurgiBox system. These, in combination with the SolidWorks models will inform design changes to the SurgiBox system and help the SurgiBox team quantitativly assess the quality of their designs.<br>by Sandra L. Walter.<br>S.B.<br>S.B. Massachusetts Institute of Technology, Department of Mechanical Engineering
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Custer, Nicholas C. "Ash impacts on gasoline particulate filter performance and service life." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/100142.
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Thesis: S.M. in Mechanical Engineering, and S.M in Naval Architecture and Marine Engineering, Massachusetts Institute of Technology, Department of Mechanical Engineering, 2015.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 71-74).<br>New regulations in the United States and Europe, designed to address climate change concerns by reducing greenhouse gas emissions, are causing increased use of gasoline direct-injection (GDI) engines in light-duty vehicles (LDV). Separate new regulations that aim to reduce particulate emissions to address air pollution concerns are taking effect concurrent with greenhouse gas limitations in both jurisdictions. GDI engines are proven to create more particulate emissions than previously utilized port-injection technology. Increasing particulate emissions rates combined with falling regulatory particulate emissions limits requires new strategies to reduce these emissions from gasoline powered LDVs. Particulate filters have been successfully implemented to reduce particulate emissions from diesel engine exhaust for over a decade. Diesel particulate filters have a demonstrated filtration efficiency of 95% or greater and have reduced diesel particulate mass (PM) emissions by one to two orders of magnitude. GDI engines require no more than one order of magnitude reduction in particulate emissions to meet new regulations. Existing particulate filter technology in use in diesel vehicles is capable of reducing GDI engine emissions to new regulatory levels; however, it is proposed that these reduction may be achievable through means other than gasoline particulate filters (GPF). A GPF will create an additional back-pressure in the engine exhaust system that will reduce engine power and efficiency. This backpressure will increase as PM is trapped in the filter and decrease as combustible PM removed. A buildup of incombustible ash present in engine-out PM will increase the baseline backpressure of the filter during the course of its service life. It is important to understand the impact of ash on the filter pressure drop performance before implementing GPF to meet new emissions regulations. This study builds on existing diesel particulate filter technology and demonstrates through experimental results the mechanisms by which ash increases GPF pressure drop. Ash deposits are also shown to increase the light-off temperature of three-way catalyst coatings in GPF.<br>by Nicholas C. Custer.<br>S.M. in Mechanical Engineering, and S.M in Naval Architecture and Marine Engineering
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Wang, Qiang. "FILTER PERFORMANCE UNDER SIMULATED REAL-WORLD CONDITIONS." VCU Scholars Compass, 2016. http://scholarscompass.vcu.edu/etd/4464.
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Evaluating the performance of filter media for filtration applications is essential to assure design engineers and users that filter device will deliver promised performance for specific applications under the environmental stress. The study of particle loading characteristics of filter media in the laboratory setting is typically performed under the steady flow conditions, i.e., at the constant particle concentration and flow rate. In reality, filtration products are operated under the situations that the flow rate and mass concentration of particles are varied in time. The success of translating the laboratory data to estimate the performance of filter media in the fields is thus limited. It is necessary to investigate the performance of filter media under the real-world conditions, i.e., unsteady flow rate and mass concentration to bridge the gap.
The overall goals of this research are (1) to study the performance of filter medium under unsteady conditions (i.e., the performance of respirator filter media under simulated breathing conditions); and (2) to investigate the issue of non-uniform particle deposition on HVAC filter panels. A new experimental setup was developed to accomplish the former goal. Numerical modeling tool, Computational fluid dynamics (CFD), was applied to achieve the latter objective……
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Beatty, Reinhard. "Notch filter control of magnetic bearings to improve rotor synchronous response." Thesis, Massachusetts Institute of Technology, 1988. http://hdl.handle.net/1721.1/37485.
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Monahan, Gregory James. "Characterizing ash properties and effects on Diesel Particulate Filter flow resistance." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/104140.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.<br>This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.<br>Cataloged from student-submitted PDF version of thesis.<br>Includes bibliographical references (pages 98-99).<br>As a result of increasingly stringent emissions regulations, Diesel Particulate Filters (DPF) have become a widespread method of reducing particulate emissions in both on and off highway diesel engine use. This particular aftertreatment system is chosen for its high filtration efficiency and relative simplicity. The porous ceramic substrate captures the particulate matter which is comprised of combustible soot and inorganic metallic ash. While the soot can be cleared from the filter through high temperature oxidation, the small amount of ash remains in the filter. The presence of these soot and ash particles creates an increase in the flow resistance of the filter which creates more backpressure on the engine and results in a decrease in fuel economy. Over the life of the filter, the ash particles become a significant portion of particulate matter in the filter and the resulting flow resistance. While the effects of ash and soot on filter performance have been extensively studied, the underlying deposition mechanisms and effects of various ash properties are not well understood. The focus of this research is to investigate the effects of ash properties such as packing density and chemistry on the flow resistance of both the ash cake layer and the filter substrate. The results of this and other research can support the optimization of operating conditions, regeneration strategies, and lubricant additive formulations for decreased system backpressure. Additionally, this research seeks to develop and improve advanced diagnostic tools in order to bridge the gap between macro scale quantifiable flow resistance and micro scale deposition characteristics. Using both high resolution X-Ray CT imaging and flow simulation tools, a method is tested by which values for ash and filter permeability can be calculated to investigate local micro scale filter phenomena or various lab and field samples.<br>by Gregory James Monahan.<br>S.M.
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Kassakian, Peter William. "Audio denoising using wavelet filter banks aimed at real-time application." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/80508.
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Fowler, William Mark. "Experimental validation of the inverse structural filter force estimation technique." Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/17264.
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Wang, Guanxiong. "Multi-level filter based on H shaped channels." Thesis, University of Birmingham, 2016. http://etheses.bham.ac.uk//id/eprint/7053/.
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Micro and nano filtration is a crucial fundamental process in biological, biomedical and chemical engineering fields. This project aims to establish a multilevel filter for separation and purification complex bio-components mixtures by size in both micro and nano scales; generalize the design methodology of this multi level filter; optimise traditional nanofilter and eventually develop a multi level filter for rapid micro volume sample filtration. During the study and improvement of traditional filter, a new type of multi level filter for sequential separation based on H shaped channels were put forward in this thesis. The methodology of designing this type multi level filter was built and verified with simulations. A general path for multi level filter chip design was established and demonstrates with examples and experiments. A new fabrication process for multi depths channel on the same surface was put forward during the examples design. The fabrication experiments demonstrated the feasibility of this fabrication process and the recipes of these three fabrication processes were given by the experiments. Simulations on both 2D and 3D filters were described and discussed. The angle effect of angular H shaped channels was studied with COMSOL Multiphysics® Modeling Software.
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Sousounis, Marios Charilaos. "Electro-mechanical modelling of tidal arrays." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/31089.
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The aim of this study is to present, compare and improve the options of power transmission for tidal current arrays. The potential to generate low or zero carbon power from the world’s tides is increasing as technology moves forward. The technically available tidal current energy resource, the resource that can be captured using existing technology, in the United Kingdom can supply a significant amount of the UK electricity demand. Even though tidal current devices have similarities to offshore wind turbines in many aspects, a number of characteristics differentiate the approach needed regarding power transmission and drive-train design. Some of these characteristics are: predictable direction and speed of the tidal current, predetermined available area in a tidal channel, less swept area due higher density of water, continuous underwater operation and smaller distances to shore. This thesis is based on the hypothesis that tidal current energy can be harnessed using today’s technology in an efficient manner. Technology progression never stops and as new materials and methods become available the cost of utilising tidal current energy will drop in the years to come. However, the research question that has to be asked is whether using today’s technology tidal arrays can be an alternative source of electrical power. In order to respond to this research question electromechanical models of tidal current devices have been developed in detail, from resource to the grid connection, using mathematical linear and non-linear programming in MATLAB/Simulink. The tidal models developed include the tidal resource, the tidal turbine with pitch control, geared induction and synchronous generators, the power electronics with the generator controller, the grid side controller, the cables for power transmission, the filters and the grid connection. All the modelling aspects of this study are presented in Chapter 3. Single tidal current devices were compared using different generator technologies, squirrel cage induction generator or permanent magnet synchronous generator, and different location of the power converters, in the nacelle near the generator or many kilometres apart from the generator. Regarding the generator technology, results showed that even though differences are minor, the permanent magnet synchronous generators are more efficient. Regarding the location of the power converters results showed that positioning the power converters in the nacelle always yields fewer electrical losses but component accessibility is minimised due to the underwater operation of the tidal current device. A key focus aspect of the study is the power transmission option with onshore converters which is presented in detail. Using this concept it is possible to generate electricity from tidal current devices but at the same time keep the highest possible system reliability despite the continuous underwater operation. This concept has been used in the first demonstration tidal current arrays developed by Andritz Hydro Hammerfest. What is more, data provided by Andritz Hydro Hammerfest were utilised in order to validate the simulation models. In this study a step forward is taken regarding the concept of keeping the converter dry and controlling the tidal current generator from afar. An algorithm is developed to design power harmonic filters for systems that use long distance controls. Power harmonic filters allow the long distance control system to operate reliably under all conditions but generate significant electrical losses. The power harmonic filter design algorithm presented in this thesis estimates the exact filter parameters so that the filter ensures maximum system reliability and generate minimum possible losses. In addition tidal array topologies using this concept are developed. The final part of this thesis compares a number of different tidal array topologies based on resource to grid efficiency and component accessibility for maintenance. Results showed that when tidal current devices are clustered per four turbines on offshore platforms it is efficient to use as many clusters as possible connected to a single cable whose both ends are connected to the grid. Locating the power converters in the nacelle yields fewer electrical losses compared to locating the power converters on the offshore platform. However, the difference is minimised because the distance between the tidal current device and the offshore platform is the least possible. Having the power converters on an offshore platform is beneficial in terms of accessibility for maintenance and operation because they are not underwater. The results and the methodology from this thesis can be extended to other offshore renewable energy systems such as the wind and wave. In addition, this study can be used as a stepping stone for decision making by tidal current developers.
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Bahr, Michael J. Nav E. (Michael James) Massachusetts Institute of Technology. "Passive regeneration : long-term effects on ash characteristics and diesel particulate filter performance." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/81583.
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Thesis (Nav. E. and S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2013.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (p. 87-90).<br>Diesel particulate filters (DPF) have seen widespread growth as an effective means for meeting increasingly rigorous particle emissions regulations. There is growing interest to exploit passive regeneration of DPFs to reduce fuel consumption accompanying traditional active regeneration. Incombustible material or ash, mainly derived from metallic additives in the engine lubricant, accumulates in the DPF over time. This ash accumulation increases flow restriction and rise in pressure drop across the DPF. The growth of pressure drop adversely impacts engine performance and fuel economy. This study built upon previous research to evaluate the different effects of regeneration strategy on ash packing and distribution within DPFs. Since passive regeneration relies on a catalyzed reaction, the interactions of ash with the catalyst will play an important role. Passive regeneration is specifically dependent on exhaust feed gas composition, exhaust conditions including temperature and flow rate, catalyst type and configuration, and the state of DPF loading during prior to passive regeneration. The goal of the study is to address the long-term effects of regeneration parameters on ash accumulations and the resulting impact of ash on the DPF catalyst performance. Experiments were conducted that focused on pressure drop measurements over the lifetime of diesel particulate filters with different regeneration methods coupled with post mortem ash characterization. These experiments provide insight to how these regeneration methods impact the DPF performance. These results, among few fundamental data of this kind, correlate changes in diesel particulate filter performance with exhaust conditions, regeneration strategy, and ash morphological characteristics. Outcomes are useful in optimizing the design of the combined engine-aftertreatment- lubricant system for future diesel engines, balancing the necessities of additives for adequate engine protection with the requirements for robust aftertreatment systems.<br>by Michael J. Bahr.<br>Nav.E.and S.M.
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Adjorlolo, Eric (Eric James Kofi), and Silpa Kaza. "Design of fuel efficient brick kiln for ceramic water filter firing in Ghana." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/40404.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.<br>"June 2007."<br>Includes bibliographical references (p. 104-105).<br>Ceramic water filters are currently produced in Ghana in order to provide a household solution to contaminated water. These filters, locally branded with the name Kosim filter by originating from Potters for Peace-Nicaragua, are heated using a generic kiln that is not attuned to the filters' current characteristics. The need for water filters is currently greatest in Northern Ghana, where more than one million people do not have access to safe water, but filter production occurs in Southern Ghana. A custom kiln will strengthen the filters, increase the filter's survival rate, and eliminate the need to transport the filters. Additionally, the traditional fuel source, wood, is extremely scarce, thus indicating the need for a more fuel efficient method of firing the kiln. Our thesis focuses on evaluating prior kilns built in developing countries and designing a fuel efficient kiln for Northern Ghana, where a kiln does not currently exist and fuel is scarce.<br>by Eric Adjorlolo and Silpa Kaza.<br>S.B.
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Beauboeuf, Daniel P. "Microscopy investigations of ash and particulate matter accumulation in diesel particulate filter surface pores." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/59894.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2010.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (p. 60).<br>There has been increased focus on the environmental impact of automobile emissions in recent years. These environmental concerns have resulted in the creation of more stringent particulate matter emissions regulations in the United States and European Union. These limits have forced diesel engine manufacturers to reduce particulate matter (PM) emissions by an order of magnitude beginning in 2007. Diesel particulate filters (DPF) provide the most effective means of reducing PM emissions from diesel exhaust. DPFs can reduce over 99% of PM in the exhaust. DPF effectiveness is limited by the accumulation of ash. Ash is comprised of incombustible material from engine lubricants. Engine oil additives based on P, Zn, S, Ca, and Mg are responsible for the majority of ash. Ash accumulation in DPFs reduces their useful life by plugging the filter's inlet channels. Ash deposition leads to increased pressure drop across the DPF, which reduces the engine's performance and negatively impacts fuel economy. The process of ash accumulation in DPF channels is not well understood. This research is focused on exploring the ash interactions with DPF walls, pores, and the catalyst washcoat. Based on scanning electron microscopy analysis of ash loaded DPFs from the field and from filters loaded with ash in the laboratory, a mechanism for ash accumulation is presented.<br>by Daniel P. Beauboeuf.<br>S.B.
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Johnson, Hyrum David 1972. "Real-time identification for ground vehicle trajectory estimation using extended Kalman filter residual analysis." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/80015.
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Wang, Yujun Ph D. Massachusetts Institute of Technology. "Modeling and interpreting the observed effects of ash on diesel particulate filter performance and regeneration." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/87985.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2014.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 123-130).<br>Diesel particulate filters (DPF) are devices that physically capture diesel particulates to prevent their release to the atmosphere. Diesel particulate filters have seen widespread use in on- and off-road applications as an effective means for meeting increasingly stringent particle emissions regulations. Although the soot deposit can be removed by regeneration, the incombustible material - ash, primarily derived from metallic additives in the engine lubricant, accumulates in the DPF channels with the increasing vehicle mileage or equivalent running hours. Ash accumulation inside filter increases the flow restriction and reduces the filter soot storage capacity, which results in higher filter regeneration frequencies and larger engine fuel penalty. Combined with experimental observations, DPF models are built to investigate the fundamental mechanisms of DPF aging process. The DPF soot and ash loading model, based on porous media filtration theory, is applied to understand the soot deposition across the substrate wall with soot and ash cake layer formation. DPF models are also used to investigate the process of ash transport and catalyst deactivation with increasing ash load level. DPF ash aging is found to have negative effect on passive regeneration due to the catalyst deactivation and diffusion resistance of ash cake layer. Besides, at given amount of ash load, the effects of ash spatial distribution on DPF performance are studied via simulation. It is found that the ash end plug has significant influences on DPF pressure drop while ash radial and axial distributions have minor effects. At known ash and substrate property, DPF performance can be optimized according the sensitivity map developed from this study. DPF model is beneficial to interpret the experimental observations and it is applied to predict the effects of certain factors, like flow rate and deposit level, on DPF performance. At the same time, modeling results are useful in optimizing the design of the combined engine-aftertreatment-lubricant system for future diesel engines and in understanding the requirements for robust aftertreatment systems.<br>by Yujun Wang.<br>Ph. D.
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Getachew, Julian (Julian B. ). "Analysis and sourcing of the mechanical equipment required for a ceramic pot filter production facility." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/68839.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (p. 118).<br>Research was done into identifying and sourcing the mechanical equipment required for manufacturing ceramic pot filters, specifically for use in the Pure Home Water factory in Northern Ghana. The pieces of equipment identified were a hammer mill, a mixer, a pug mill, and a mechanical press with molds for pressing the filters. Evaluative criteria for each machine were developed, and machines available from manufacturers and machines produced locally were evaluated based on these criteria. Several machines fit the evaluative criteria and were recommended for the Pure Home Water facility. The Meadows Model 5 hammer mill was recommended for purchase from the manufacturer. Of the mixers researched, the mixer made by RDI-C, the Bluebird 24S mixer, and the mixer designed by Prof. Manny Hernandez all satisfy the requirements of Pure Home Water. The pug mill recommended for Pure Home Water was the Venco 75mm pug mill. The Mani Press and the paraboloid molds were also recommended for the Pure Home Water facility.<br>by Julian Getachew.<br>S.B.
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Yap, Kwee Chye. "Incorporating target mensuration system for target motion estimation along a road using asynchronous filter." Thesis, Monterey, Calif. : Naval Postgraduate School, 2006. http://bosun.nps.edu/uhtbin/hyperion.exe/06Dec%5FYap.pdf.
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Thesis (M.S. in Engineering Science (Mechanical Engineering))--Naval Postgraduate School, December 2006.<br>Thesis Advisor(s): Isaac I. Kaminer "December 2006." Includes bibliographical references (p. 41). Also available in print.
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Al-Shohani, Wisam A. M. "Development and performance of concentrated optical water filter for photovoltaic applications." Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8213/.
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New Concentrated Optical Water Filter (COWF) for Photovoltaic (PV) applications is investigated. The COWF is placed in front of the PV module in order to reduce the thermal load on the PV. The COWF acts as a spectrum splitter to absorb the unwanted radiation and convert it to heat, and allow the useful radiation to reach the PV. The COWF consists of two parts; Optical Water Filter (OWF) and V-trough Solar Concentrator (VTSC). The OWF consists of two glass panels with specific gab filled with water which flows carrying away the heat and preventing it from reaching the PV. However, the disadvantage of using the OWF with PV is some reduction in the electrical power output of the PV due to optical losses. Therefore, VTSCs are developed to be integrated with OWF to overcome the optical losses. The VTSC consists of two reflectors placed as a (V) letter in front of the OWF in order to increase the solar radiation received by the PV to overcome the optical losses by the OWF. Overall, it can be concluded that COWF can enhance the electrical performance of the PV and reduce the PV temperature simultaneously relative to the PV module without COWF.
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Rautenbach, Jeremy Brian. "Improving production yields in bio-pharmaceutical filter media." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/111937.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, in conjunction with the Leaders for Global Operations Program at MIT, 2017.<br>Thesis: M.B.A., Massachusetts Institute of Technology, Sloan School of Management, in conjunction with the Leaders for Global Operations Program at MIT, 2017.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 89-91).<br>This thesis presents methods to identify sources of variation in rolled goods manufacturing by defining the critical input process parameters, and the application of statistical process control. Sources of variation are prioritized according to a process control hierarchy, and reduced or eliminated through iterative cycles of rapid experimentation. This work emphasizes the value of team work, breaking down the organizational barriers between departments, knowledge sharing and the importance of a scientific approach to problem solving. FilterCo manufactures and assembles filter media catering to the ultrafiltration market growing at ~12% over the next five years. In a high growth scenario, production yield variability presents on-time delivery complications while below target yields drive significant scrap value. As FilterCo seeks to improve product lead time for its customers, while reducing WIP inventory, it must seek to maximize OEE with respect to product yield, equipment performance and availability. The variation identification, reduction and process control methodologies presented in this thesis are demonstrated to advance the goal of reducing production yield variation. The impact of the work has been verified on three filter media grades and have shown ~40% reduction in production yield variation, and rolled throughput yield improvements of ~30%. These improvements on the three membrane grades alone have resulted in an annualized saving equivalent to 60% of the total 2015 scrapped membrane value.<br>by Jeremy Brian Rautenbach.<br>S.M.<br>M.B.A.
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Hohreiter, Luke A. (Luke Alfred) 1979. "The effects of mechanical coupling on the electrical impedance of MEMS resonators for UHF filter applications." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/27080.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.<br>Includes bibliographical references (p. 137-138).<br>(cont.) This thesis presents finite elements based simulations of electromechanical transfer functions for resonator and filter geometries. These Finite Element Analysis (FEA) simulations are performed using the ANSYS software and demonstrate the significance of mechanical coupling between MEMS longitudinal-mode bar (L-Bar) resonators. An analytical model and equivalent circuit are derived for a single L-Bar resonator. The analytical derivation is validated with an FEA model having the same material parameters and boundary conditions. The center frequency and resonant impedance produced by the FEA model are within 1% of the analytical values. A boundary condition study is undertaken to determine the sensitivity of the L-Bar resonator model to changes in the peripheral geometry and displacement constraints. A comparison of FEA results indicates that a simple resonator model with only tether supports yields impedance and center frequency values comparable to those of more complex geometries. When compared to initial experimental results from an actual resonator, the simulated electrical output corresponds well to the actual transfer function. This study also introduces a method for calculating the parameters of the resonator's equivalent circuit model from simulated (or measured) transfer function data. The method is tested on simulation data for which a mechanical Quality factor is designated. Comparing the prescribed mechanical Q to the extracted circuit Q provides a consistency check for the technique. The parameter extraction technique is a useful first attempt to devise a comprehensive method for determining circuit parameters that will reliably reproduce the transfer function of an actual resonator. Finally, a new resonator topology<br>(cont.) is presented that employs mechanical coupling between L-Bar resonators to improve upon the output of a single bar and create alternative configurations for filter design at Draper. The new coupled bar geometry can be configured as either a single-port resonator or a multi-port filter. The benefits of mechanical coupling are investigated for both configurations. In discussion of future work, optimized filter parameters are presented, along with suggestions for achieving these values.<br>by Luke A. Hohreiter.<br>S.M.
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Servi, Amelia Tepper. "An experimental and analytical exploration of the effects of manufacturing parameters on ceramic pot filter performance." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/81808.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2013.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (p. 163-165).<br>Ceramic pot filters (CPF) are a promising low-cost option for household water treatment, providing a barrier of protection against-microbiological contaminants for households with or without reliable piped water supplies. The goal of this thesis is to provide CPF manufacturers with tools to increase their ability to reach performance objectives for CPF flow rate, bacteria removal and strength. This is achieved by experimentally determining relationships between these three aspects of performance and three manufacturing values: percentage rice husk, rice husk size and wall thickness. These relationships are used to run a series of optimizations that result in design recommendations including the recommendation to increase wall thickness to improve bacteria removal and to tightly control rice husk size to maintain consistent flow rates. In addition to the experimental relationships, this author seeks a theoretical explanation of filter performance. Through this process, the author determined that hydraulic head can be increased without decreasing bacteria removal and that incomplete combustion should not be of primary concern to manufacturers. While the results in this study are preliminary, the systematic approach to the CPF design shown here can be used in future studies to further analyze and improve the CPF design.<br>by Amelia Tepper Servi.<br>S.M.
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Morrow, Ryan (Ryan Michael). "Investigations of ash layer characteristics and ash distribution in a diesel particulate filter using novel lubricant additive tracers." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/59949.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2010.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (p. 59, 62).<br>Diesel particulate filters (DPF) are currently widely used in various applications as a means of collecting particulate matter in order to meet increasingly stringent particle emissions regulations. Over time, the DPF slowly accumulates incombustible material or ash, mostly from the metallic additives present in the engine lubricant. This build up of accumulated ash leads to an increase in flow restriction and therefore an increase in pressure drop along the DPF. The increased pressure drop negatively impacts engine performance and fuel economy, and it also requires eventual filter removal for ash cleaning. While the major effects of ash accumulation on DPF performance are known, the fundamental underlying mechanisms are not. This work is focused on understanding key mechanisms, such as the soot deposition and the ash formation, accumulation, and distribution processes, which play a major role in determining the magnitude of the ash effect on DPF pressure drop. More specifically, it explores the location of ash deposit accumulation inside the DPF channels, whether in a layer along the filter walls or packed in a plug at the rear of the channels, which is one of the key factors controlling DPF pressure drop. A specialized experiment was set up by running three different lubricants, each with its own unique additive tracer, sequentially through a diesel burner system. Scanning electron microscopy (SEM) was used to analyze the evolution of the ash deposits in the DPF samples in order to explain the specific mechanisms and processes controlling ash properties and their effect on DPF pressure drop. The experimental results were compared and correlated with previous DPF test data and theoretical models, providing additional insight to optimize diesel particulate filter performance. The results are useful in optimizing the design of the engine, aftertreatment, and lubricant systems for future diesel engines, balancing the requirements of additives for adequate engine protection with the requirements for robust after treatment systems.<br>by Ryan Morrow.<br>S.B.
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Munnis, Sean (Sean Andrew). "Synergistic effects of lubricant additive chemistry on ash properties impacting diesel particulate filter flow resistance and catalyst performance." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/67798.
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Thesis (S.M. in Mechanical Engineering and S.M. in Naval Architecture and Marine Engineering)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (p. 147-152).<br>Diesel particulate filters (DPF) have seen widespread use in recent years in both on- and offroad applications as an effective means for meeting the increasingly stringent particulate emission regulations. Overtime, engine-out particulate matter composed of soot and incombustible ash accumulate within the DPF. Although soot can be removed by oxidation, ash remains within the filter and substantially accumulates over time leading to increased flow restriction thus a pressure drop across the filter. An increased pressure drop negatively affects the engine performance & fuel economy leading to the need for filter removal and cleaning. The adverse effects of ash accumulation on DPF performance have been extensively studied in the past and are well know yet the underlying mechanisms for their presence are still not well understood. The ash which accumulates within a DPF is a product of a number of factors including engine wear and corrosion as well as trace metals in diesel fuel, but the majority of the engine out ash is derived from specific metallic additives placed within the diesel lubricant. This work examines the properties of ash derived from specific single lubricant additives, as well as simple combinations, and their adverse effect on DPF performance. Specific ash properties are examined such as porosity, permeability, deposit thicknesses and packing densities along the filter channel walls as a cake layer as well as the resultant end plugs in the rear of the filter channels. Through a combined approach of experiments and theoretical models, the link between the material properties and characteristics of ash derived from single additives as well as combinations can be made to their respective impact on DPF performance. The results of this research are among a few of its kind and aim to help optimize the design of advanced diesel aftertreatment systems as well as lubricant formulations to satisfy the additive requirements for engine protection while mitigating the negative effects on DPF performance.<br>by Sean Munnis.<br>S.M.in Mechanical Engineering and S.M.in Naval Architecture and Marine Engineering
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Taylor, Michael Eric 1970. "System identification and control of an Arleigh Burke Class Destroyer using an extended Kalman filter." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/91716.
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Thesis (Nav.E.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2000.<br>Includes bibliographical references (leaves 88-92).<br>by Michael Eric Taylor.<br>Nav.E.<br>S.M.
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Moosavi, Seyed Mahmoud. "DERIVATIVE-FREE KALMAN FILTER-BASED CONTROL OF NONLINEAR SYSTEMS WITH APPLICATION TO TRANSFEMORAL PROSTHESES." Cleveland State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=csu1502481884476173.
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Malmborg, Petter. "Engine air filter requirements : How different running conditions affect service life." Thesis, Karlstads universitet, Institutionen för ingenjörsvetenskap och fysik (from 2013), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-74614.
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The internal combustion engine requires clean air in order to operate without problems the entire service life. The air filter acts as a barrier between the ambient air ridden with particulate matter, and the sensitive interior of the engine. Several factors affect the air filter performance, such as pressure drop, efficiency, and dust holding capacity. Many external factors affect the air filter too, such as driving style, engine type, if the car is equipped with hybrid propulsion et cetera. The scope for this thesis work aims to extend the knowledge of air filtration for the customer, in this case, Volvo Cars. A comprehensive literature study along with benchmarking of competitors acts as a foundational approach. Regarding air filter service life, three parameters are identified as the most significant: dust holding capacity, efficiency and pressure drop over the filter element. Reverse engineering shows some competitor design decisions. A model of estimating air consumption is developed using a data-driven approach with real-world driving data as a basis. The model shows how much the actual air consumption varies between different markets and various engines. As a result, the service lifetime of air filters in certain cars with certain engines may be extended or allow for a smaller filter size for the same service lifetime.
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Gautam, Ishwor. "Quaternion based attitude estimation technique involving the extended Kalman filter." University of Akron / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron1556196539847396.
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Isaac, Benson. "Inverse Kinematics and Extended Kalman Filter based Motion Tracking of Human Limb." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1406809906.
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Hasan, Mohammed. "The filtration and oxidation characteristics of a diesel oxidation catalyst and a catalyzed particulate filter : development of a 1-D 2-layer model /." Available online. Click here, 2005. http://sunshine.lib.mtu.edu/ETD/THESIS/hasanm/Thesis.pdf.
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Zhang, Yi 1973. "Cuff-less continuous monitoring of beat-to-beat blood pressure using a Kalman filter and sensor fusion." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/88860.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2000.<br>Includes bibliographical references (leaves 59-60).<br>by Yi Zhang.<br>S.M.
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Bergström, Sara. "Bergets mekaniska hållfasthet i Aitikgruvan." Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-105060.
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Throughout the years the mining company Boliden Mineral AB have had difficulties producing a working fine filter for their tailing pond at the Aitik copper mine. The problem with the fine filter occurs when it gets placed on the tailing pond wall. Coarse grains break down into fine grains and the entire composition of the fine filter is changed. The material that is used to produce the fine filter comes from the mine’s own waste rock supply. The primary waste rock in Aitik comprises of heterogeneous gneiss and pegmatite. To determine why the waste rock isn’t holding together well enough the mechanical strength of the rock is investigated. Huge differences for the mechanical strength both exist between the different rock types, but also in the different kinds of the gneiss. The effect of the explosions, used to mine the ore, and the crushing machine also impacts on the mechanical strength of the rock. Good mechanical strength is found in rock that has a high amount of secondary transformation like epidote and bad mechanical strength from foliated rock. To get the best mechanical properties it is suggested to exploit epidote transformed rock found in deformation zones, adjacent to the ore deposit or the pegmatite intrusions. It is also recommended to use less powerful charge when blasting rock material that will be used for production of the fine filter.
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Cannon, Brandon Jeffrey. "Fault Detection for Unmanned Aerial Vehicles with Non-Redundant Sensors." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/5308.
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To operate, autonomous systems of necessity employ a variety of sensors to perceive their environment. Many small unmanned aerial vehicles (UAV) are unable to carry redundant sensors due to size, weight, and power (SWaP) constraints. Faults in these sensors can cause undesired behavior, including system instability. Thus, detection of faults in these non-redundant sensors is of paramount importance.The problem of detecting sensor faults in non-redundant sensors on board autonomous aircraft is non-trivial. Factors that make development of a solution difficult include both an inability to perfectly characterize systems and sensors as well as the SWaP constraints inherent with small UAV. An additional challenge is the ability of a fault-detection method to strike a balance between false-alarm rate and detection rate.This thesis explores two model-based methods of fault-detection for non-redundant sensors, a Kalman filter based method and a particle filter based method. The Kalman filter based method employs tests of mean and covariance on the normalized innovation sequence to detect faults, while the particle filter based method uses a function of the average particle weights.The Kalman filter based approach was implemented in real time on board an autonomous rotorcraft using an extended Kalman Filter (EKF). Faults tested included varied levels of bias, drift, and increased noise. Metrics included false-alarm rate, detection rate, and delay to detection. The particle filter based approach was implemented on a simulated system. This was then compared with an implementation of the EKF based approach for the same system. The same fault types and metrics were also used for these tests.The EKF based method of fault-detection performed well onboard the autonomous rotorcraft and should be generalizable to other systems for which an EKF or Kalman filter can be implemented. The theory indicates that the particle filter based algorithm should have performed better, though the simulations showed poor detection characteristics in comparison to the Kalman filter based method. Future work should be performed to explore improvements to the particle filter based method.
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Yearsley, Jonathan D. "Product Family Design Using Smart Pareto Filters." BYU ScholarsArchive, 2008. https://scholarsarchive.byu.edu/etd/1664.
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Product families are frequently used to provide consumers with a variety of appealing products and to help maintain reasonably low production costs for manufacturers. Three common objectives in the design of product families are used to balance the interests of both consumers and manufacturers. These objectives are to maximize (i) product performance, (ii) product distinctiveness as perceived by the consumer, and (iii) product commonality as seen by the manufacturer. In this thesis, three methods are introduced that use multiobjective optimization and Smart Pareto filtering to satisfy the three objectives of product family design. The methods are progressive in nature and begin with the selection of product family members using Smart filtering and develop through the establishment of scale- based product platforms to the design of combined scale- based and module-based product platforms. Each of the methods is demonstrated using a well-know universal electric motor example problem. The results of each method are then compared to a benchmark electric motor product family that was previously defined in the literature. Additionally, a pressure vessel example problem is used to further demonstrate the first of the three methods.
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Kirimlioglu, Serdar. "Multisensor Dead Reckoning Navigation On A Tracked Vehicle Using Kalman Filter." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614939/index.pdf.
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The aim of this thesis is to write a multisensor navigation algorithm and to design a test setup. After doing these, test the algorithm by using the test setup. In navigation, dead reckoning is a procedure to calculate the position from initial position with some measured inputs. These measurements do not include absolute position data. Using only an inertial measurement unit is an example for dead reckoning navigation. Calculating position and velocity with the inertial measurement unit is highly erroneous because, this calculation requires integration of acceleration data. Integration means accumulation of errors as time goes. For example, a constant acceleration error of 0.1 m/s^2 on 1 m/s^2 of acceleration will lead to 10% of position error in only 5 seconds. In addition to this, wrong calculation of attitude is going to blow the accumulated position errors. However, solving the navigation equations while knowing the initial position and the IMU readings is possible, the IMU is not used solely in practice. In literature, there are studies about this topic and in these studies<br>some other sensors aid the navigation calculations. The aiding or fusion of sensors is accomplished via Kalman filter.
In this thesis, a navigation algorithm and a sensor fusion algorithm were written. The sensor fusion algorithm is based on estimation of IMU errors by use of a Kalman filter. The design of Kalman filter is possible after deriving the mathematical model of error propagation of mechanization equations.
For the sensor fusion, an IMU, two incremental encoders and a digital compass were utilized. The digital compass outputs the orientation data directly (without integration). In order to find the position, encoder data is calculated in dead reckoning sense. The sensor triplet aids the IMU which calculates position data by integrations. In order to mount these four sensors, an unmanned tracked vehicle prototype was manufactured. For data acquisition, an xPC&ndash<br>Target system was set.
After planning the test procedure, the tests were performed. In the tests, different paths for different sensor fusion algorithms were experimented. The results were recorded in a computer and a number of figures were plotted in order to analyze the results. The results illustrate the benefit of sensor fusion and how much feedback sensor fusion is better than feed forward sensor fusion.
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Bruton, Jared Thomas. "Packing Sheet Materials Into Cylinders and Prisms Using Origami-based Approaches." BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/5998.
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Packing sheet materials into cylinders and prisms using Origami-based approaches (Soft Origami or traditional Origami) is of interest in fields where sheet materials need folded into cylinders or prisms. Fully-dense packing has application in fields where a sheet material is to be folded with minimal gaps into a cylinder or prism. Partially-dense packing is applicable to fields where gaps are required between packed surfaces or where hollow volumes are to be filled, such as in fluid filter design. Soft Origami is explored as a method for folding soft-sheet materials into fully-dense cylinders. Two fold patterns, the "flasher'' and the "inverted-cone fold,'' are explored for packing soft-sheet materials into cylindricals. An application to driver's side automobile airbags is successfully performed, and deployment tests are completed to compare the influence of packing method and origami pattern on deployment performance. In total, two origami patterns and six packing methods are examined for folding soft-sheet materials into fully-dense cylindrical prisms, and it is shown that modifying the packing method impacts deployment performance. A special case of the Miura-ori, the ninety-degree case, is briefly explored as a traditional Origami method for packing arbitrary-shaped sheet materials into fully-dense arbitrary prisms. Examples are shown and it is concluded that this pattern can be used to configure a large number of fully-dense packed prisms with configurable characteristics.Finally, patterns that fold into partially-dense cylindrical prisms are examined using traditional Origami approaches and their efficiency compared. Efficiency is defined as the ratio of the surface area of a pattern compared to an idealized high-surface-area model. Patterns include traditional (non-Origami-based) fluid filter patterns (the Basic Pleat and M-pleat) and cylindrical Origami patterns (the Accordion and Kresling). An offset crease method is used to modify the Accordion and Kresling Origami patterns so the comparison is objective. Results are presented that determine which individual pattern variations have the highest efficiency at different outside-to-inside diameter ratios. Ranges over which each pattern is most efficient are presented. It is concluded that based purely on geometry, the M-pleat provides the highest overall efficiency, but depending on other factors each pattern is viable for different purposes.
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Blanchard, Emmanuel. "Polynomial Chaos Approaches to Parameter Estimation and Control Design for Mechanical Systems with Uncertain Parameters." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/26727.
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Mechanical systems operate under parametric and external excitation uncertainties. The polynomial chaos approach has been shown to be more efficient than Monte Carlo approaches for quantifying the effects of such uncertainties on the system response. This work uses the polynomial chaos framework to develop new methodologies for the simulation, parameter estimation, and control of mechanical systems with uncertainty.
This study has led to new computational approaches for parameter estimation in nonlinear mechanical systems. The first approach is a polynomial-chaos based Bayesian approach in which maximum likelihood estimates are obtained by minimizing a cost function derived from the Bayesian theorem. The second approach is based on the Extended Kalman Filter (EKF). The error covariances needed for the EKF approach are computed from polynomial chaos expansions, and the EKF is used to update the polynomial chaos representation of the uncertain states and the uncertain parameters. The advantages and drawbacks of each method have been investigated.
This study has demonstrated the effectiveness of the polynomial chaos approach for control systems analysis. For control system design the study has focused on the LQR problem when dealing with parametric uncertainties. The LQR problem was written as an optimality problem using Lagrange multipliers in an extended form associated with the polynomial chaos framework. The solution to the Hâ problem as well as the H2 problem can be seen as extensions of the LQR problem. This method might therefore have the potential of being a first step towards the development of computationally efficient numerical methods for Hâ design with parametric uncertainties.
I would like to gratefully acknowledge the support provided for this work under NASA Grant NNL05AA18A.<br>Ph. D.
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VALTERSSON, Magnus. "Methods for On-Chip Spectroscopy." Thesis, KTH, Mekatronik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-244973.
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Technology is rapidly becoming more compact and engineers are investigating new applications that are possible with this compact technology. For example photography has recently become an obvious part in our lives due to the shrinking of cameras. If there was a way to implement a light spectrum sensor into our phones there are a lot of applications this could be used for. For example the visual light spectrum can be used to detect the difference between materials in ways that our eyes can not. It could also be used to detect the amount of UV-light when outdoors or be used as an infrared camera. In order for this to be possible the spectrum sensor can’t be too big which makes the common spectrometer a bad choice for the application. This thesis compares two methods of detecting visual light spectrum suitable for On-Chip applications. One method utilize well-defined optical filters while the other works by incorporating an algorithm that boosts the performance of less well-defined optical filters. A simulation was created to assess the performance of the methods and one of these spectrometers were then designed into a circuit board to test the performance in real environments. The results concluded that the algorithmic method currently has better performance to the same price but that the purely optically filtered method is set to be stronger in the future.<br>Dagens teknik blir snabbt mer kompakt och ingenjörer undersöker nya tillämpningar som är möjliga med den här kompakta tekniken. Till exempel fotografi har nyligen fått en självklar plats i våra liv när kameratekniken blivit mindre. Om det fanns ett sätt att implementera en ljusspektrumsensor i våra telefoner så hade det funnits en mängd applikationer för detta. Till exempel så kan ljusspektrumet användas för att märka skillnad på material som våra ögon inte kan. Det kan också användas för att mäta mängden UV-ljus när man är ute, eller användas som en infraröd kamera. För att det här ska vara möjligt så kan inte spektrumsensorn vara alltför stor vilket gör en traditionell spektrometer blir olämplig. Den här avhandlingen jämför två metoder för att mäta det synliga ljusspektrumet som är passande för att placeras direkt på ett kretskort. En metod använder specifika optiska filter medan den andra metoden använder en algoritm för att förbättra utslaget hos mindre specifika optiska filter. En simulation skapades för att bedöma de två metoderna och ett kretskort designades sedan för att implementera en av spektrometrarna på och testa beteendet i verkliga miljöer. Resultaten visade att den algoritmiska metoden just nu har bättre prestanda men att den rent optiskt filtrerade metoden troligtvis kommer vara starkare i framtiden.
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Saleh, Ahmed M. "MICRO- AND MACRO-SCALE MODELING OF FILTER AGING: EFFECTS OF PARTICLE POLY-DISPERSITY AND FIBER CROSS-SECTIONAL SHAPE." VCU Scholars Compass, 2015. http://scholarscompass.vcu.edu/etd/3987.
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The goal of this study is to further advance the state of the art in developing self-sufficient methods to predict the performance of an aerosol filter. The simulation methods developed in this study are based on first principles and consequently, they do not rely on empirical correction factors. These simulation methods can be used to predict the instantaneous collection efficiency and pressure drop of a filter under dust-loading conditions. In the current study, 3-D micro- and macroscale CFD models are developed to simulate the service life of flat-sheet and pleated filters. These CFD micro- and macroscale models are also used to quantify the effects of a fiber’s cross-sectional shape on the performance of the resulting filter. As fiber manufacturing methods are rapidly advancing, these fibers are becoming more accessible. The filtration performance of trilobal fibers is compared with their circular counterparts under dust-loading conditions. Our results show that trilobal fibers do not outperform circular ones except in very limited conditions, revealing no advantage over circular fibers.
In addition, a fast but approximate 2-D model is developed to predict the filtration performance of flat and circular pleated filters. The predictions of the model are compared with predictions from the more sophisticated CFD models, as well as with experimental work in the literature. Our 2-D model developed in this study is aimed at providing the aerosol filtration industry with a fast but fairly accurate method of designing pleated filters. With a CPU-time of practically zero, the developed model allows one to conduct a broad parameter study, altering the parameters that affect the filtration performance of pleated filters. Using this model, predictive correlations for dust-loaded pleated filters are presented. These correlations allow one to estimate the instantaneous pressure drop and collection efficiency of pleated filters effectively.
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Asmatulu, Ramazan. "Advanced Chemical-Mechanical Dewatering of Fine Particles." Diss., Virginia Tech, 2001. http://hdl.handle.net/10919/26604.
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In the present work, novel dewatering aids and a novel centrifuge configuration were developed and applied for the purpose of dewatering fine particles. Three different types dewatering reagents were tested in different filtration and centrifugation units. These chemicals included low-HLB surfactants, naturally occurring lipids, and modified lipids. Most of these reagents are insoluble in water; therefore, they were used in solutions of appropriate solvents, such as light hydrocarbon oils and short-chain alcohols. The role of these reagents was to increase the hydrophobicity of the coal and selected mineral particles (chalcopyrite, sphalerite, galena, talc, clay, phosphate, PCC and silica) for the dewatering. In the presence of these reagents, the water contact angles on the coal samples were increased up to 90o. According to the Laplace equation, an increase in contact angle with the surfactant addition should decrease the capillary pressure in a filter cake, which should in turn increase the rate of dewatering and help reduce the cake moisture. The use of the novel dewatering aids causes a decrease in the surface tension of water and an increase in the porosity of the cake, both of which also contribute to improved dewatering.
A series of batch-scale dewatering tests were conducted on a variety of the coal and mineral samples using the novel dewatering aids. The results obtained with a Buchner funnel and air pressure filters showed that cake moistures could be reduced substantially, the extent of which depends on the particle size, cake thickness, drying time, reagent dosage, conditioning time, reagent type, sample aging, water chemistry, etc. It was determined that use of the novel dewatering aids could reduce the cake formation time by a significant degree due to the increased kinetics of dewatering. At the same time, the use of the dewatering aids reduced the cake moistures by allowing the water trapped in smaller capillaries of the filter cake. It was found that final cake moistures could be reduced by 50% of what can be normally achieved without using the reagents. However, the moisture reduction becomes difficult with increasing cake thickness. This problem can be minimized by applying a mechanical vibration to the cake, spraying a short-chain alcohol on the cake and by adding a small amount of an appropriate coagulant, such as alum and CaCl2 to the coal and mineral slurries.
The novel dewatering aids were also tested using several different continuous filters, including a drum filter, disc filter and horizontal belt filter (HBF). The results obtained with these continuous filtration devices were consistent with those obtained from the batch filters. Depending on the coal and mineral samples and the type of the reagent, 40 to 60% reductions in moisture were readily achieved.
When using vacuum disc filters, the cake thickness increased substantially in the presence of the novel dewatering aids, which could be attributed to the increased kinetics of dewatering. A dual vacuum system was developed in the present work in order to be able to control the cake thickness, which was necessary to achieve lower cake moistures. It was based on using a lower vacuum pressure during the cake formation time, while a full vacuum pressure was used during the drying cycle time. Thus, use of the dual vacuum system allowed the disc filter to be used in conjunction with the novel dewatering aids. Its performance was similar to that of HBF, which is designed to control cake thickness and cake formation time independently.
The effectiveness of using the novel dewatering aids were also tested in a full-continuous pilot plant, in which coal samples were cleaned by a flotation column before the flotation product was subjected to the disc filter. The tests were conducted with and without using novel dewatering aids. These results were consistent with those obtained from the laboratory and batch-scale tests.
The novel centrifuge developed in the present work was a unit, which combined a gravity force and air pressure. The new centrifuge was based on increasing the pressure drop across the filter cake formed on the surface of the medium (centrifuge wall). This provision made it possible to take advantage of Darcy s law and improve the removal of capillary water, which should help lower the cake moisture. A series of tests were conducted on several fine coal and mineral particles and obtained more than 50% moisture reduction even at very fine particle size (2 mm x 0).
Based on the test results obtained in the present work, two proof-of-concept (POC) plants have been designed. The first was for the recovery of cyclone overflows that are currently being discarded in Virginia, and the other was for the recovery of fines from a pond in southern West Virginia. The former was designed based on the results of the plant tests conducted in the present work. Cost vs. benefit analyses were conducted on the two POC plants. The results showed very favorable internal rates of return when using the novel dewatering aids.
Surface chemistry studies were conducted on the coal samples based on the results obtained in the present investigation. These consisted mainly of the surface characterization of the coal samples (surface mineral composition, surface area, zeta potential, x-ray photoelectron microscopy (XPS)), acid-base interactions of the solids and liquids, dewatering kinetic tests, contact angle measurements of the coal samples and surface force measurements using AFM. In addition, carbon coating on a silica plate using palsed laser deposition (PLD) and Langmuir-Blodgett (LB) film deposition tests were conducted on the sample to better understand the surfactant adsorption and dewatering processes. The test results showed that the moisture reductions on the fine particles agree well with the surface chemistry results.<br>Ph. D.
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Cerit, Ersen Recep. "Investigation Of The Effect Of Oxidation Filters On The Particulate Emissions Of Diesel Engines." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12607561/index.pdf.
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Oxidation filters are used to decrease particulate emissions commonly. In this study, design of a particulate trap to produce an alternative, low cost filter has been aimed. An experimental setup has been installed according to standards to carry out tests of these designed filters. Electronic measurement and control systems have been attached to this setup to increase efficiency of experiments.
Two filter designs have been used in the experiments. First design consists of aluminum wire cloth. Second design is sheet metal structure, which includes three longitudinal cells. Metal chip is used as filter material. Empty filter tests have been performed firstly, and then experiments have been repeated with aluminum, iron, and copper chip addition in filter.
Copper chip test results are better than other metal chip for first experiments. Afterwards, experiments have been repeated with varying copper chip amount. Suitable copper chip amount was determined based on fuel consumption rate of the engine.
As a result, designed filter reduce the particulate emissions with high efficiency. Although, carbon monoxide, and carbon dioxide gaseous emissions increase with designed filter, hydro carbon emissions decrease.
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Wells, James Z. "Application of Path Prediction Techniques for Unmanned Aerial System Operations in the National Airspace." University of Cincinnati / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ucin161710909594714.
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Herbert, Robert. "Perforation of Inferior Vena Cava Filters." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1492694912566491.
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Beach, Jason M. "Development of Tailsitter Hover Estimation and Control." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/3820.
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UAVs have become an essential tool in many market segments, particularly the military where critical intelligence can be gathered by them. A tailsitter aircraft is a platform whose purpose is to efficiently merge the range and endurance of fixed-wing aircraft with the VTOL capabilities of rotorcraft and is of significant value in applications where launch and recovery area is limited or the use of launch and recovery equipment is not desirable. Developing autopilot software for a tailsitter UAV is unique in that the aircraft must be autonomously controlled over a much wider range of attitudes than conventional UAVs. Assumptions made in conventional estimation and control algorithms are not valid for tailsitter aircraft because of routine operation around gimbal lock. Quaternions are generally employed to overcome the limitations Euler angles; however, adapting the attitude representation to work at a full range of attitudes is only part of the solution. Kalman filter measurement updates and control algorithms must also work at any orientation. This research presents several methods of incorporating a magnetometer measurement into an extended Kalman filter. One method combines magnetometer and accelerometer sensor data using the solution to Wahba's problem to calculate an overall attitude measurement. Other methods correct only heading error and include using two sets of Euler angles to update the estimate, using quaternions to determine heading error and Euler angles to update the estimate, and using only quaternions to update the estimate. Quaternion feedback attitude control is widely used in tailsitter aircraft. This research also shows that in spite of its effective use in spacecraft, using the attitude error calculated via quaternions to drive flight control surfaces may not be optimal for tailsitters. It is shown that during hover when heading error is present, quaternion feedback can cause undesired behavior, particularly when the heading error is large. An alternative method for calculating attitude error called resolved tilt-twist is validated, improved, and shown to perform better than quaternion feedback. Algorithms are implemented on a commercially available autopilot and validation is performed using hardware in loop simulation. A custom interface is used to receive autopilot commands and send the autopilot simulated sensor information. The final topic covered deals with the tailsitter hovering in wind. As the tailsitter hovers, wind can cause the tailsitter to turn such that the wind is perpendicular to the wings. Wind tunnel data is taken and analyzed to explain this behavior.
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Gillis, Robert W. "Low-Thrust Assited Angles-Only Navigation." DigitalCommons@USU, 2011. https://digitalcommons.usu.edu/etd/1001.
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Tradition spacecraft proximity operations require large and expensive on-board sensors and significant ground support. Relative angle measurements can be obtained from small, simple, and inexpensive on-board sensors, but have not traditionally been used for proximity operation because of difficulty generating rang information. In this thesis it is shown that useful relative range data can be generated provided that the spacecraft is experiencing a small continuous thrust such as would be provided by a low-thrust propulsion system.
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Christensen, Randall S. "Linear Covariance Analysis For Gimbaled Pointing Systems." DigitalCommons@USU, 2013. https://digitalcommons.usu.edu/etd/1766.
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Linear covariance analysis has been utilized in a wide variety of applications. Historically, the theory has made significant contributions to navigation system design and analysis. More recently, the theory has been extended to capture the combined effect of navigation errors and closed-loop control on the performance of the system. These advancements have made possible rapid analysis and comprehensive trade studies of complicated systems ranging from autonomous rendezvous to vehicle ascent trajectory analysis. Comprehensive trade studies are also needed in the area of gimbaled pointing systems where the information needs are different from previous applications. It is therefore the objective of this research to extend the capabilities of linear covariance theory to analyze the closed-loop navigation and control of a gimbaled pointing system. The extensions developed in this research include modifying the linear covariance equations to accommodate a wider variety of controllers. This enables the analysis of controllers common to gimbaled pointing systems, with internal states and associated dynamics as well as actuator command filtering and auxiliary controller measurements. The second extension is the extraction of power spectral density estimates from information available in linear covariance analysis. This information is especially important to gimbaled pointing systems where not just the variance but also the spectrum of the pointing error impacts the performance. The extended theory is applied to a model of a gimbaled pointing system which includes both flexible and rigid body elements as well as input disturbances, sensor errors, and actuator errors. The results of the analysis are validated by direct comparison to a Monte Carlo-based analysis approach. Once the developed linear covariance theory is validated, analysis techniques that are often prohibitory with Monte Carlo analysis are used to gain further insight into the system. These include the creation of conventional error budgets through sensitivity analysis and a new analysis approach that combines sensitivity analysis with power spectral density estimation. This new approach resolves not only the contribution of a particular error source, but also the spectrum of its contribution to the total error. In summary, the objective of this dissertation is to increase the utility of linear covariance analysis for systems with a wide variety of controllers and for whom the spectrum of the errors is critical to performance.
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Shivaprasad, Shreyas. "Model Based Investigation of Lean Gasoline PM and NOx Control." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1408970125.
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Zagorski, Scott B. "Modeling, Control and State Estimation of a Roll Simulator." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1349900540.
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Long, Guo. "Subband Adaptive Filtering for Active Broadband Noise Control with Application to Road Noise inside Vehicles." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1595846098921553.
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