Dissertations / Theses on the topic 'Inertia'
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1
Townsend, William A. "Inertia-gravity waves beyond the inertial latitude." Thesis, Keele University, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.534319.
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Norman, Thomas. "Evolution under inertia." Thesis, University of Oxford, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.275759.
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Carvalho, André Roncaglia de. "The conceptual evolution of inflation inertia in Brazil." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/12/12140/tde-30092015-161420/.
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This work aims to contribute to the wider body of research in history of economics in Brazil by focusing on the conceptual evolution of inflation inertia. Its motivation lies in the conceptual gap that appeared, following disinflation in 1994, between the stabilization debates carried out in the 1980s and the way economists in Brazil began to describe downwardly rigid inflation patterns from the 1990s onwards. More precisely, we explore the \"inertial inflation episode\" as a chapter in a longer tradition of adaptations, to country-specific realities, of theoretical influences coming from the economics profession at the international level, in the late 1970s, when the inertial inflation hypothesis was brought to the fore. Our narrative reveals that this stubborn inflationary phenomenon had been previously dealt with in the debates in Latin America about growth and inflation back in the 1950s and 1960s, where a host of contributions sprung from various traditions, which were gradually synthesized by the saw-tooth model of real wages, also known as Simonsen-Pazos mechanism. We analyze the recurrent opposition between a monetarist- and a heterodox structuralist-type of thinking in their two rounds, in the 1950s and again in the 1980s. The connection between these two opposing schools is operated by the contributions by Mario Henrique Simonsen and the self-declared neo-structuralist economists at PUC-Rio. Based on a careful and detailed analysis of the latter\'s modeling strategies and conclusions, we show that, along the 1980s, these economists gradually shift towards a more ecumenical approach, inviting monetarist elements into their analyses while downplaying the relevance of the inertial component. Finally, when the 1990s came, the rise of a macroeconomic consensus began to conceptualize \"inflation inertia\" as the time delay between a real or monetary shock and the response by price level changes, leaving the concept of \"inflation persistence\" to account for the deviations of inflation away from its equilibrium value, a view that undergirds how most Brazilian economists now understand this phenomenon. We assess how \"inflation inertia\" has been understood in the aftermath of the monetary reform in Brazil in 1994, by analyzing the backstage papers that circulated within the economic team in charge of the Real Plan. We conclude that there are elements of continuity between the two rounds as regards the concept of inertia, but that they are now stripped of their previous dense historical and institutional substance.O presente trabalho busca contribuir para a literatura de história do pensamento econômico brasileiro, ao estudar a transformação do conceito de inércia inflacionária no Brasil desde os debates sobre estabilização na década de 1980 até o período pós-Real, mudança essa que permanece inexplicada pela literatura. Mais precisamente, o trabalho busca verificar a hipótese de que a inflação inercial não passou de um episódio de uma longa tradição de adaptações teóricas de influências oriundas de economistas estrangeiros, em especial na década de 1970, quando a hipótese de uma inflação inercial foi levantada. Nossa narrativa revela que o fenômeno da rigidez inflacionária já havia sido previamente compreendido e teorizado nos debates na América Latina, nas décadas de 1950 e 1960, quando inúmeras contribuições foram eventualmente sintentizadas no modelo de rendas contratuais sob inflação no formato de \"dente-de-serra\", ou o assim chamado mecanismo Simonsen-Pazos. A narrativa adota a controvérsia entre monetaristas e estruturalistas em seus dois momentos como eixo da análise, para mostrar como o desaparecimento dessa oposição coincide com a emergência do consenso macroeconômico em escala internacional. Baseando-se em uma análise cuidadosa e detalhada das contribuições dos economistas neo-estruturalistas da PUC-Rio e da onipresente influência de Simonsen como um sintetizador das contenciosas escolas, o trabalho apresenta evidências documentais de uma transformação estruturalista da segunda geração. Ao longo dos anos 1980, esses economistas gradualmente convergiram para uma abordagem mais ecumênica com relação aos monetaristas, reduzindo a importância do componente inercial da inflação e ampliando a relevância de aspectos usualmente associados à ortodoxia econômica. Finalmente, no período pós-Real, passa a predominar no país um conceito de inércia inflacionária que constrasta com a visão anterior dos economistas atuando no referido plano de estabilização. Esse novo conceito está associado à emergência da \"nova síntese neoclássica\", na qual a inércia é compreendida como o atraso na resposta dos níveis de preço a choques monetários ou reais, enquanto o conceito de persistência inflacionária representa desvios duradouros da inflação com relação ao seu nível de equilíbrio. Para compreender se essa mudança pode ser considerada uma ruptura com relação ao passado, analisam-se os artigos que circularam nos bastidores do Plano Real dentro da equipe econômica. Nosso trabalho conclui que há elementos de continuidade entre os dois momentos no que se refere ao conceito de inércia, os quais aparecem agora com uma representação analítica desprovida da substância histórica e institucional que o conceito outrora abarcava.
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Kinderknecht, Kelsy. "Sleep Inertia in Children." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1366335599.
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McGarry, Joshua Elwood. "Small parts inertia tester." The Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=osu1413447952.
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LAZOR, DANIEL R. Jr. "CONSIDERATIONS FOR USING THE DYNAMIC INERTIA METHOD IN ESTIMATING RIGID BODY INERTIA PROPERTY." University of Cincinnati / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1093047356.
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Knox, Eleanor. "Geometry, inertia and spacetime structure." Thesis, University of Oxford, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.527342.
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Kutluay, Emir. "Identification Of Inertia Tensor Of Vehicles." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/3/12608796/index.pdf.
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The aim of this thesis is to develop a methodology for obtaining mass properties of a vehicle using specific test rig. Investigated mass properties are the mass, location of center of gravity and the inertia tensor. Accurate measurement of mass properties of vehicles is crucial for vehicle dynamics research. The test rig consists of a frame on which the vehicle is fixed and which is suspended from the ceiling of the laboratory using steel cables. Mass and location of center of gravity are measured using the data from the test rig in equilibrium position and basic static equations. Inertia tensor is measured using the data from
dynamical response of the system. For this purpose an identification routine which employs prediction error method is developed using the built&ndashin functions from the System Identification Toolbox of MATLAB®
. The experiment was also simulated using Simmechanics Toolbox of MATLAB®
. Identification code is verified using the results of the experiment simulations for various cases.
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Flitton, Jonathan C. "Inertia dominated spreading of thin films." Thesis, University of Nottingham, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369039.
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Hameury, Stéphane. "The hygrothermal inertia of massive timber connstructions." Doctoral thesis, KTH, Byggvetenskap, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4200.
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The work presented in this Doctoral dissertation concerns the ability of heavy timber structures to passively reduce the fluctuations of the indoor temperature and of the indoor relative humidity, through the dynamic process of heat and moisture storage in wood. We make the hypothesis that the potential offered by the hygrothermal inertia of heavy timber structures is significant, and that it could provide a passive way of regulating the indoor climate. This ultimately could results in a decrease of the energy demand from the Heating, Ventilating and Air Conditioning systems. In this Thesis, the author tries to characterise and quantify the significance of the hygrothermal inertia providing by the heavy timber constructions. The experimental studies contain an in-situ measurement campaign carried out at the Vetenskapsstaden building located in Stockholm and erected in 2001. The results from the test campaign show that a heavy timber construction may contribute to buffer the indoor temperature. A direct quantification of the moisture stored in the wood structure is measured regarding the year-to-year indoor humidity fluctuations. It was however hardly possible to directly quantify the moisture storage potential offered by the structure regarding the day-to-day indoor relative humidity fluctuations because of the low sensitivity of the measuring technique used. In regard to the limitations noticed during the in-situ measurements, laboratory measurements were launched to develop new methods to determine the day-to-day hygric performances of wood exposed indoor. A new method based on the Magnetic Resonance Imaging technology was developed and is intended to provide information about the Moisture Buffer Value measured according to a NORDTEST protocol, and about the moisture distribution in wood with high spatial resolution. The Moisture Buffer Value of untreated Scots pine measured with this method is in accordance with the gravimetric method provided by the NORDTEST protocol. The Moisture Buffer Value of coated Scots pine was also investigated and it is normally assumed that any coatings will decrease the Moisture Buffering Capacity of the structure. The results show however that for specific coating such as waterborne alkali silicate coating, the Moisture Buffering Capacity of the structure may on the contrary be improved. At last, numerical simulations were carried out. They were based upon the extension of a modular simulation environment IDA ICE 3.0, with the implementation of a specific model for heat and moisture transport in a wood. The results obtained pinpoint the highly synergetic effects between the indoor moisture loads, the ventilation rate, the outdoor climate and the moisture interactions with the structure. The outcomes also show that the Moisture Buffering Capacity of a heavy timber structure is appreciable. The structure is able to even out substantially the day-to-day indoor relative humidity fluctuations for a certain range of ventilation rate.QC 20100825
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Hameury, Stéphane. "The hygrothermal inertia of massive timber constructions /." Stockholm : Division of building materials, Royal Institute of Technology, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4200.
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Putzig, Nathaniel E. "Thermal inertia and surface heterogeneity on Mars." Diss., Connect to online resource, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3239385.
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Bennetts, Christopher Dean. "Chassis dynamometer software, inertia determination and recalibration." Thesis, University of Canterbury. Mechanical Engineering, 2002. http://hdl.handle.net/10092/6594.
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The University of Canterbury chassis dynamometer exists to enable specific and
repeatable motor vehicle testing to be carried out in the University’s Department of
Mechanical Engineering. Dynamometer testing is invaluable in the development of
new vehicle technologies, such as electric and hybrid configurations, and the
assessment of existing vehicles’ performance. This thesis includes a description of
the dynamometer, and of the recalibration and software work that has been carried
out to enable computer-controlled vehicle testing of a flexible and reliable nature.
In order to exert a known force at the wheels of a vehicle on the chassis
dynamometer, the appropriate equations of motion must be applied to the known
inertial mass and frictional characteristics of the dynamometer system. These
equations of motion are discussed in terms of the chassis dynamometer and their
application in the simulation of realistic on-road vehicle forces. Several techniques
have been proposed to determine the system friction and inertia, and the most
appropriate method was chosen on the basis of repeatability and equipment
limitations.
Dynamometer control and data acquisition software has been written in the C++
programming language, which includes automated routines for the calibration of the
chassis dynamometer as well as several vehicle testing regimes. Analysis software
has been created to enable graphical display of test data and the calculation of useful
parameters such as energy consumption and efficiency.
Several tests were conducted on a motor vehicle owned by the University of
Canterbury, with a view to determining the effectiveness of the testing procedures,
and the accuracy of the dynamometer instrumentation. In light of these test results
and observations made during the dynamometer development, a number of potential
improvements to the system have been proposed.
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Aspden, Jonathan Maclean. "Inertia-gravity wave generation : a WKB approach." Thesis, University of Edinburgh, 2011. http://hdl.handle.net/1842/33317.
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The dynamics of the atmosphere and ocean are dominated by slowly evolving, large-scale motions. However, fast, small-scale motions in the form of inertia-gravity waves are ubiquitous. These waves are of great importance for the circulation of the atmosphere and oceans, mainly because of the momentum and energy they transport and because of the mixing they create upon breaking. So far the study of inertia-gravity waves has answered a number of questions about their propagation and dissipation, but many aspects of their generation remain poorly understood. The interactions that take place between the slow motion, termed balanced or vortical motion, and the fast inertia-gravity wave modes provide mechanisms for inertia-gravity wave generation. One of these is the instability of balanced flows to gravity-wave-like perturbations; another is the so-called spontaneous generation in which a slowly evolving solution has a small gravity-wave component intrinsically coupled to it. In this thesis, we derive and study a simple model of inertia-gravity wave generation which considers the evolution of a small-scale, small amplitude perturbation superimposed on a large-scale, possibly time-dependent °ow. The assumed spatial-scale separation makes it possible to apply a WKB approach which models the perturbation to the flow as a wavepacket. The evolution of this wavepacket is governed by a set of ordinary differential equations for its position, wavevector and its three amplitudes. In the case of a uniform flow (and only in this case) the three amplitudes can be identifed with the amplitudes of the vortical mode and the two inertia-gravity wave modes. The approach makes no assumption on the Rossby number, which measures the time-scale separation between the balanced motion and the inertia-gravity waves. The model that we derive is first used to examine simple time-independent flows, then flows that are generated by point vortices, including a point-vortex dipole and more complicated flows generated by several point vortices. Particular attention is also paid to a flow with uniform vorticity and elliptical streamlines which is the standard model of elliptic instability. In this case, the amplitude of the perturbation obeys a Hill equation. We solve the corresponding Floquet problem asymptotically in the limit of small Rossby number and conclude that the inertia-gravity wave perturbation grows with a growth rate that is exponentially small in the Rossby number. Finally, we apply the WKB approach to a flow obtained in a baroclinic lifecycle simulation. The analysis highlights the importance of the Lagrangian time dependence for inertia-gravity wave generation: rapid changes in the strain field experienced along wavepacket trajectories (which coincide with fluid-particle trajectories in our model) are shown to lead to substantial wave generation.
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Stevens, Peter Alastair. "Shear zone properties of inertia friction welds." Thesis, University of Birmingham, 2015. http://etheses.bham.ac.uk//id/eprint/5770/.
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Inertia weld process variables arc characterised using empirical relations that arc functions of the weld input parameters, allowing the variables to be predicted for any future production welds. The techniques for establishing the empirical relations can be applied to future alloy system for inertia welding by using significantly refined test matrices, reducing the development costs of new welds. Power loss in the bearings for two inertia welding machines is characterised by using hydrostatic bearing theory and several experimental techniques. This allows energy-based empirical relations for new alloy systems to be developed using sub-scale welds only, reducing the cost of implementing future production welds. Average temperature and now stress of the plasticised zone of welds is used to characterise the average shear zone thickness. Two separate models arc developed and arc found to correlate well with each other and with experimental observations. This work helps to improve the mechanistic understanding of inertia weld interfaces and can be used in computational fluid dynamics models to characterise the bond-line cleaning mechanism.
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Kitaguchi, Hiroto. "Inertia friction welded RR1000 and Inconel718 microstructure." Thesis, University of Birmingham, 2011. http://etheses.bham.ac.uk//id/eprint/819/.
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Precipitation hardening Ni based superalloys have been widely used in gas turbine engine components owing to their stable microstructure at high temperature. To assemble these components, joining technology is necessary and friction welding is used for the joints which are suitable for large component welding, taking advantage of its superior mechanical properties compared to fusion welding. Inertia friction welded RR1000 and Inconel718 microstructure was studied. In this study, grain boundaries were intensively characterized to rationalize the intergranular susceptible area from the microstructure point of view.
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Fregelius, Martin. "An experimental approach on linear synthetic inertia." Licentiate thesis, Uppsala universitet, Elektricitetslära, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-437982.
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The interest in renewable energy has significantly increased in the last decades which has led to an increased amount of renewable energy sources in the grid. In the Nordic grid, the major contribution to renewable energy is hydro power and wind power and an increase in the amount of wind power is expected in the future. The increase in wind power and decommissioning of nuclear power is expected to decrease the mechanical inertia in the system which helps to stabilise the electrical grid frequency. The inertia is expected to decrease by a factor of two within 20 years and other solutions for frequency stability must be implemented to assure a stable power system. At Uppsala University several projects are investigating how grid-connected energy storages can increase the frequency stability with a high penetration of intermittent renewable energy sources. In this thesis, a linear synthetic inertia control algorithm is implemented on a national Instruments FPGA for controlling the power flow from a supercapacitor energy storage via a two-level three-phase inverter. The control strategy is evaluated both via simulations and experimental tests in a nano grid. The results of the simulations and experimental work are presented and show that it is possible to calculate the frequency derivative in real time to reduce the frequency ROCOF and nadir. The results of the increased frequency stability are presented.
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Hartin, Travis L. "REPRESENTATIONAL INERTIA IN PRESCHOOLERS’ OBJECT LABEL LEARNING." Kent State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=kent1322573040.
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Foster, Christina. "Effect of Maximizing Tendency on Inaction Inertia." Xavier University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=xavier1409922837.
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Fleitas, Perla Sebastian, and Perla Sebastian Fleitas. "Essays on Inertia, Dynamics and Market Competition." Diss., The University of Arizona, 2017. http://hdl.handle.net/10150/625583.
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The central goal of my dissertation is to answer important questions about market design in health care when consumers have inertia, using modern industrial organization tools. The presence of consumer inertia in several markets has been well established in the literature, although we still know very little about how inertia affects the way markets work. In my dissertation, I shed light on these issues in the context of different institutional settings of health care sectors in different countries. Health care markets are extremely relevant because of their huge impacts on the quality of life and on mortality of individuals. In times when the expenditure on health care is increasingly high in modern economies, a better understanding of how these markets work is needed in order to decrease costs and improve their performance. The first chapter disentangles the effects of reductions in switching costs and in the length of contracts (lock-in) on consumer welfare, using quasi-experimental variation in the length of contracts in the Uruguayan health care system. In the second chapter, I study the effect of supply-side firm responses in terms of pricing and offering of new products, on consumer welfare in Medicare Part D in the U.S. Finally, the third chapter studies the effects of increased competition induced by reductions of consumer inertia, on quality and returns to skills for physicians, using uniquely detailed data from the Uruguayan health care sector. The use of tools from the field of industrial organization allows me to combine a solid theoretical background with clearly identified reduced-form and structural models, to analyze the welfare implications of equilibrium behavior in these markets, and to evaluate policy interventions and regulations aimed at improving welfare.
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Guzman, Christopher Abraham. "Counting Threshold Graphs and Finding Inertia Sets." BYU ScholarsArchive, 2013. https://scholarsarchive.byu.edu/etd/3847.
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This thesis is separated into two parts: threshold graphs and inertia sets. First we present an algorithmic approach to finding the minimum rank of threshold graphs and then progress to counting the number of threshold graphs with a specific minimum rank. Second, we find an algorithmic and more automated way of determining the inertia set of graphs with seven or fewer vertices using theorems and lemmata found in previous papers. Inertia sets are a relaxation of the inverse eigenvalue problem. Instead of determining all the possible eigenvalues that can be obtained by matrices with a specific zero/nonzero pattern we restrict to counting the number of positive and negative eigenvalues.
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Duckwitz, Daniel [Verfasser]. "Power System Inertia : Derivation of Requirements and Comparison of Inertia Emulation Methods for Converter-based Power Plants / Daniel Duckwitz." Kassel : Universitätsbibliothek Kassel, 2019. http://d-nb.info/1190050145/34.
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Pagulayan, Ralindo M. "Determining the human ability to judge inertia during a dynamic pushing task." Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-07212009-040421/.
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Ciornei, Mihaela-Cristina. "Role of magnetic inertia in damped macrospin dynamics." Phd thesis, Palaiseau, Ecole polytechnique, 2010. http://pastel.archives-ouvertes.fr/pastel-00006013/en/.
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Tabatabaei, Seyed Mahmood. "Improvement of inertia effects in slender-body theory." Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=23379.
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This research develops an analytical method for predicting the hydrodynamic force experienced by a long slender solid body of arbitrary cross-sectional shape and body centreline configuration, subjected to an unbounded uniform fluid flow. It is assumed the slenderness parameter, K (the ratio of the body cross-sectional length scale the body length) is small ($ ll 1$), the body centreline radius of curvature is everywhere large (of order body length), the cross-sectional shape varies slowly alone the body length, and the Reynolds number $R sb{e}$, based on the body length is of order unity.The inner flow solution for an arbitrary cross-section is illustrated by applying the complex variable method for a body with an elliptical cross-section, which is extendable to any cross-sectional shape.
The novelty of this research is the improvement of the approximation of the force per unit length in slender body theory when inertia effects are not negligibly small. (Abstract shortened by UMI.)
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Bennett, Christopher J. "Inertia friction welding of high strength aerospace alloys." Thesis, University of Nottingham, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.576153.
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Inertia friction welding is an important industrial joining technique for the production of axisymmetric components. Two parts, one rotating and the other stationary, are brought together under axial load and rotational kinetic energy stored in a flywheel is transformed into thermal energy and plastic deformation through friction at the interface between the work pieces. The process is quick and repeatable and generates good quality welds with a small heat affected zone (HAZ) One of the main objectives of this research was to produce a modelling tool that can be used to represent the welding of high strength aerospace alloys with particular reference to shaft applications. The commercial software DEFORM-2D was used as it contains a 2.5D modelling capability suitable for this application and can be easily used by industry. The aim of the process modelling tool is to reduce development time and cost by the use of a process modelling tool which would mean fewer development welds are required for new material combinations and geometries. Initial models created were based on the nickel-based superalloy, Inconel 718 and the capability was then extended to the high strength steels, AerMet 100 and S/CMV, which are suitable for aero-engine shaft applications. Material data required to run weld models was defined and a test programme commissioned in order to obtain the properties for the high-strength steels. Microstructural investigations, including continuous cooling and isothermal tests were also carried to determine phase transformation information that was relevant to the welding process. This included the presence of the "bainite nose", and the volume change associated with the martensite transformation on cooling. The latter was shown to have a significant effect on the residual stresses developed in as-welded components. The volume changes are shown to act as a stress relief of up to 1000MPa in the HAZ of the weld. Experimental testing, which included thermal imaging and thermocouple measurements, was carried out in order to gain more insight into the inertia friction welding of the high strength steels. This testing also included some tests using novel welding techniques to attempt to reduce the post-weld cooling rate and the effects of these techniques on the cooling rate are presented. These tests also provided data for validation of the weld model. The research concludes that DEFORM-2D can be used to model the IFW process between high-strength aerospace materials for aero-engine shaft applications and typical results show an error of ±15% with respect to the final upset value.
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Hughes, Jason Peter. "Fluid inertia and end effects in rheometer flows." Thesis, University of Plymouth, 1998. http://hdl.handle.net/10026.1/1889.
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This thesis is concerned with the characterisation of the flow behaviour of inelastic and viscoelastic fluids in steady shear and oscillatory shear flows on commercially available rheometers. The first part of this thesis is concerned with a linear viscoelastic theory to describe the oscillatory shear flow behaviour of fluids on a Weissenberg rheogoniometer. A fluid inertia perturbation analysis is used to produce analytical formulae for correcting complex viscosity data for first and second order fluid inertia effects. In order to validate the perturbation theory we perform a simulation of the oscillatory shear flow behaviour of Newtonian and single element Maxwell fluids on a Weissenberg rheogoniometer. A theoretical prediction of end effects and fluid inertia effects on steady shear viscosity measurements of Newtonian fluids in a recessed concentric cylinder geometry is developed for a GSR controlled stress rheometer and a Weissenberg rheogoniometer. The relevant equations are solved using a perturbation analysis which is valid for low Reynolds number flows. From this theory correction formulae are produced to compensate for end effects and second order fluid inertia effects in steady shear flows on these instruments. End effects and fluid inertia effects are also investigated for power law shear thinning fluids. The final part of the thesis is concerned with a theoretical prediction of the end effect of a recessed concentric cylinder geometry on complex viscosity measurements of a generalised linear viscoelastic fluid. The linear viscoelastic theory is carried out for oscillatory shear flows on a CSR controlled stress rheometer and a Weissenberg rheogoniometer. A fluid inertia perturbation analysis is used to produce analytical formulae to correct complex viscosity data for end effects and second order fluid inertia effects. Numerically simulated oscillatory shear data is used to establish the limitations of the second order fluid inertia correction formulae which include end effects.
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Kaipio, Tero. "Control of machine drives for varying inertia systems." Thesis, University of Wolverhampton, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325980.
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Manasseh, Richard. "Inertia wave breakdown : experiments in a precessing cylinder." Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387150.
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Yang, Libin. "Modelling of the inertia welding of Inconel 718." Thesis, University of Birmingham, 2010. http://etheses.bham.ac.uk//id/eprint/760/.
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In this study, the inertia welding process was studied by both an FEM model and three analytical models. The thermal analysis shows that there is a steep temperature gradient near the mating surface, which is the cause for the existence of a band of high hydrostatic stress near the weld line. The holding effect of this high static stress is the reason for the presence of the very soft material at the welding interface. The models were used to predict the displacement of the weld line (upset) with a lambda model to describe the constitutive relation of IN718 at high temperature. The results from the different models are in broad agreement. The shear stress induced by friction at the interface is found to enlarge the upset value; its effect must be taken into account if the upset is to be predicted accurately. The extrusion of the burr during the last second of the welding is a direct result of the quick stop of the rotating part due to the balance of the momentum, which is clearly explained by the analytical mechanical model put forward in this work.
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Oluwasegun, Kunle Michael. "Microstructural characterisation of inertia friction welded RR1000 superalloy." Thesis, University of Birmingham, 2012. http://etheses.bham.ac.uk//id/eprint/3496/.
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The need for jet engines to burn fuel more effectively at higher temperatures requires the development of nickel-based superalloys containing increasing amounts of the main strengthening, stable, ordered L1\(_2\) intermetallic (Ni\(_3\)(Al, Ti)) \( \gamma\)' phase, with RR1000 being a candidate. Welding of this alloy by conventional methods has been found difficult due to a high susceptibility to heat affected zone (HAZ) liquation cracking. In order to produce welds with good joint integrity, inertia friction welding (IFW), a nominally solid state welding process, has been used to join gas turbine parts made from this alloy, based on the premise that the joining occurs below the melting point of the bulk material. The failure rate, however, is not zero. Detailed microstructural characterisation of the actual weld and of a thermo-mechanically simulated HAZ has revealed for the first time that non-equilibrium constitutional liquation of some strengthening precipitates occurs at the grain boundaries and within the grains of this alloy during IFW, with attendant formation of liquation microvoids within the HAZ. The temperature gradient across the HAZ is predicted to be 1150 \(^o\)C-1286 \(^o\)C. Hafnium-rich oxides were also found to coalesce and become smeared by friction along the weld interface, forming brittle hafnium oxide flakes. However, IFW has been found to be more effective than conventional welding techniques, always producing liquation crack-free welds within 150 \( \mu\)m of the bond line (not common in conventionally welded alloys). Micro tensile testing was used to characterise the local strength within the weld and to rationalise it with the microstructure.
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Pogson, Corrie E. "Identity and Inertia: Can Fairness Heuristics Be Changed?" University of Akron / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=akron1153169961.
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Jacoby, Thomas Norman Llyn. "Inertia-gravity wave generation by boundary layer instabilities." Thesis, University of Oxford, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.558384.
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Waves with periods shorter than the inertial period exist in the atmosphere (as inertia- gravity waves) and in the oceans (as Poincare and internal gravity waves). Such waves owe their origin to various mechanisms, but of particular interest are those arising either from local secondary instabilities or spontaneous emission due to loss of balance. Previous researchers have studied these phenomena in the laboratory, both in the mechanically-forced and the thermally-forced rotating annulus. Their generation mechanisms, especially in the latter system, have not yet been fully understood. This project aims to change that. Firstly, we present a laboratory investigation using the two layer mechanically-forced annulus. We perform a new series of experiments in which we combine an existing polarised light altimetry technique with particle imaging velocimetry. This necessi- tated a substantial rebuild of the apparatus. The new vessel enables us to measure the flow in one of the layers directly, and thus investigate the validity of a torque bal- ance calculation used by previous experimenters that was hitherto unverified. We use these results to discuss the possibility that the inertia-gravity waves seen in the two layer annulus might have been generated by a shear instability; either that of Holm- boe, or an Ekman layer instability. Our investigation suggests that whilst Holmboe's instability is unlikely to be the cause, a localised Ekman layer instability is a possible generation mechanism for the short waves seen in earlier experiments. Secondly, we perform a numerical investigation using a fully nonlinear, finite-difference, 3D Boussinesq N avier-Stokes model of the rotating thermal annulus. The model pre- dicts the generation of short waves from 'wavemaker' regions determined by strong shear and downwelling near the inner cylinder. These then propagate into the geo- strophic interior of the fluid as inertia-gravity waves, where they have been detected in previous laboratory experiments. We then show how these wavemakers are con- sistent with being due to a localised thermal boundary layer instability, which has a number of similarities to the Ekman layer instability of the two-layer annulus. Such a mechanism also has many similarities with those responsible for launching small- and meso-scale inertia-gravity waves in the atmosphere from fronts and local convection.
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Zhao, Zhiheng. "Thermal Inertia In Residential Buildings For Demand Response." Thesis, The University of Sydney, 2016. http://hdl.handle.net/2123/16018.
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A smart home energy management system has been used to reshape the electricity demand of the residential buildings widely. It normally requires understanding the capability of residential buildings’ thermal mass which revisits to the temperature flatirons and providing enough energy buffers. In this project, phase change material (PCM) was used as the virtual thermal energy storage. Basically, two parts were included: thermal modelling of residential building with PCM layer. Secondly thermal behaviour of models under different conditions (heating, ventilation and air conditioning system, fenestration, solar radiation) is discussed. Some numerical methods for thermal modelling with EnergyPlus are also presented. A conduction finite difference algorithm in EnergyPlus are applied to calculate heat transfer between ambient and zone. The results indicate that PCM layers shift and decreased the indoor temperature during peak period. Also, solar radiation and fenestration can influence its performance. A model that is easily scalable in one thermal zone and convex as a function of the control inputs is derived based on energy balance equations. The indoor temperatures are treated as control inputs together with the cooling energy exchange with the virtual thermal storage. This simplifies the enforcement of comfort, which can be imposed through appropriate constraints on the control inputs. A convex constrained optimization program was formulated to address the optimal energy management, in order to minimize the electricity cost caused by Heating, Ventilation and Air Conditioning unit.
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Abdelhakim, Boukar. "Pilotage des usinages tridimensionnels." Phd thesis, Université de Grenoble, 2014. http://tel.archives-ouvertes.fr/tel-00947691.
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Dans la plupart des entreprises de fabrication mécanique, le réglage des machines-outils est une tâche déléguée au régleur qui cherche à garantir les tolérances. Cela a pour conséquence d'augmenter le temps de réglage pour une qualité qui n'est pas au niveau souhaité. Au cours de ces six dernières années, le laboratoire SYMME a élaboré des méthodes de pilotage (Copilot-Pro®et Pilotage inertiel) pour résoudre le problème de réglage des machines-outils. Fondés sur ces deux méthodes, les travaux présentés en font une synthèse et présentent des nouvelles avancées dans le pilotage de commande numériques afin d'obtenir la meilleure qualité possible quelle que soit la complexité de la pièce. L'apport de ce travail est présenté en cinq chapitres. Le premier chapitre présente le contexte général des travaux de recherche et fait un état de l'art des travaux existants, d'une part sur le pilotage et d'autre part sur la conformité. Le pilotage consiste à réduire la variabilité autour de la cible des produits et la conformité consiste à s'assurer que la dispersion d'une caractéristique est contenue dans l'intervalle de tolérance de celle-ci. Le second chapitre revient sur les méthodes de pilotage qui consistent à établir les relations entre les caractéristiques de la pièce et les correcteurs et propose dessolutions pour améliorer le calcul de la correction en tenant compte à la fois des tolérances et des nombres de points palpés sur les surfaces de la pièce. Le troisième chapitre présente les stratégies de pilotage et met en évidence les limites des méthodes classiques de détection des situations hors contrôle qui sont la carte de contrôle de Shewhart et la carte T² de Hotelling. Le quatrième chapitre fait une synthèse des méthodologies pour faciliter le déploiement des méthodes dans l'industrie. Le cinquième chapitre présente une application expérimentale du pilotage inertiel et un témoignage de l'utilisation du pilotage matriciel dans une entreprise d'horlogerie. Une conclusion rappelle les principaux apports de ce travail.
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Ronagh, Pooya. "The inertia operator and Hall algebra of algebraic stacks." Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/58120.
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We view the inertia construction of algebraic stacks as an operator on the Grothendieck groups of various categories of algebraic stacks. We are interested in showing that the inertia operator is (locally finite and) diagonalizable over for instance the field of rational functions of the motivic class of the affine line q = [A¹]. This is proved for the Grothendieck group of Deligne-Mumford stacks and the category of quasi-split Artin stacks. Motivated by the quasi-splitness condition we then develop a theory of linear algebraic stacks and algebroids, and define a space of stack functions over a linear algebraic stack. We prove diagonalization of the semisimple inertia for the space of stack functions. A different family of operators is then defined that are closely related to the semisimple inertia. These operators are diagonalizable on the Grothendieck ring itself (i.e. without inverting polynomials in q) and their corresponding eigenvalue decompositions are used to define a graded structure on the Grothendieck ring. We then define the structure of a Hall algebra on the space of stack functions. The commutative and non-commutative products of the Hall algebra respect the graded structure defined above. Moreover, the two multiplications coincide on the associated graded algebra. This result provides a geometric way of defining a Lie subalgebra of virtually indecomposables. Finally, for any algebroid, an ε-element is defined and shown to be contained in the space of virtually indecomposables. This is a new approach to the theory of generalized Donaldson-Thomas invariants.Science, Faculty of
Mathematics, Department of
Graduate
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Ingram, Gregory O. "Experimental characterization of the effect of inertia on ductility." Thesis, Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/16087.
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Dubois, Fabien. "Tribological and vibratory approaches for amplified piezoelectric inertia motors." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSEI087.
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Les SPA sont des moteurs piézoélectriques inertiels amplifiés. Ils fonctionnent en convertissant des vibrations asymétriques en μ-déplacements par frottement, grâce au phénomène d’adhérence-glissement. Ces vibrations et ce frottement soulèvent des problématiques liées à l’usure et au bruit. Pour y répondre, ces travaux étudient les comportements tribologique et vibratoire de ces moteurs. Dans un premier temps, un tribomètre pion-plan, actionné par un SPA, a été développé. Il a permis d’observer, in-situ et en fonctionnement, les débits solides interfaciaux: le 3ème corps. Ces observations directes, couplées à des analyses post-mortem ont permis de décrypter les sollicitations tribologiques et de multiplier par dix la durée de vie des moteurs. Dans un second temps, des analyses numérique et expérimentale ont été proposées afin de mieux appréhender le comportement vibratoire des SPA. Le modèle existant, à constantes localisées, a été modifié en une version hybride, constantes localisées-FEM, plus versatile. Les tests expérimentaux ont permis de déterminer le principal contributeur acoustique et de réduire le niveau de bruit de seize dBA. Finalement, la double approche tribologie/mécanique vibratoire a permis de mieux saisir les subtilités des SPA. Elle a notamment mené au développement de structures innovantes tels qu’un moteur à trois degrés de liberté et deux moteurs rotatifsSPA are amplified piezoelectric inertia motors. They operate by converting asymmetrical vibrations into μ-displacements by means of friction through stick-slip. These vibrations and this friction raise issues related to wear and noise. So, the present work investigates both the tribological and vibratory behaviours of these motors. First, a pin-on-pad tribometer, actuated by a SPA, was developed. It led us to observe, in-situ and in operation, interfacial solid flows: the 3rd body. These direct observations carried out in conjunction with post-mortem analyses resulted in decrypting the tribological solicitations and in increasing by ten the lifetime of the motors. Second, numerical and experimental considerations have been proposed to better grasp the vibratory behaviour of SPA. The existing lumped model was modified to a more versatile hybrid lumped-FEM model. The experimental tests made it possible to determine the main acoustic contributor and to reduce the noise level by sixteen dBA. Finally, this dual - tribology/vibratory - approach provided a better understanding of the SPA intricacies. In particular, it led to develop innovative structures such as a motor with three degrees of freedom and two rotary motors
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Flores, Torres Santiago. "Characterisation of weld-features in RR1000 inertia friction welds." Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8389/.
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This thesis is an investigation into a family of features that can form during the inertia friction welding of the nickel-based superalloy RR1000. A thorough characterisation of the weld features using scanning-electron microscopy has been carried out, yielding information about their composition, microstructure, morphology and their distribution within the weld zone.
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Ting, Fang, and Huang Yiweihua. "Exploring the relation between stakeholder inertia and product requirements." Thesis, Blekinge Tekniska Högskola, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-20615.
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User inertia is a real innovation adoption problem that cannot be seen or grasped. How to overcome user inertia while introducing innovation has become a key factor in today's society. Based on the background of requirements engineering, the goal of this thesis is to study and understand the relationship between user inertia and innovation adoption, including whether the type of innovation has an impact on user adoption and how to use strategies to reduce this impact. Through an online survey of 60 users and a systematic literature review of a series of articles, we have concluded the following points: RI has a greater impact on user inertia, while II has almost no impact; neither RI nor II has a significant impact on user satisfaction. Not only that, but through literature review, we have also concluded a comprehensive strategy to deal with the adoption problem caused by user inertia.
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Amin-Javaheri, Masoud. "Parallel algorithms and architectures for the manipulator inertia matrix /." The Ohio State University, 1989. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487599963592857.
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Durisek, Nicholas J. "Conceptual design for a vehicle inertia measurement facility (VIMF)." Connect to resource, 1993. http://rave.ohiolink.edu/etdc/view.cgi?acc%5Fnum=osu1249497423.
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Qureshi, Fassahat Ullah. "Fast frequency response services for low inertia power systems." Thesis, The University of Sydney, 2019. http://hdl.handle.net/2123/20764.
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Power systems in the world are undergoing a major transformation due to the displacement of conventional synchronous generators (SGs) and increasing penetration of non-synchronous renewable energy sources (NS-RES) in the electricity grids. A computationally efficient analytical tool incorporating FFR services to determine the frequency performance of a low synchronous inertia power system is a major contribution of this thesis. First, we study the impact of high penetration of NS-RES on the frequency stability of the electricity grids. Second, we study the impact of reduced synchronous inertia on the power system stability of the electricity grid. Third, we study the frequency stability of a low inertia power system by means of the time domain simulations. We considered the impact of different grid topologies on the frequency performance of the system because frequency dynamics are also affected by grid topology in a power system. Furthermore, we developed a wind-based FFR service and used that service to improve the frequency stability of a low inertia power system. Finally, we developed a computationally efficient analytical tool incorporating FFR services to improve the frequency stability of a low inertia power system by avoiding computationally expensive simulations. The tool identifies the locations in a low inertia power system that are highly sensitive to the disturbance by computing rate of change of frequency (RoCoF) sensitivities with respect to synchronous inertia for the placement of FFR services in those locations. Hence in this thesis, we have presented both simulation-based and system-theoretic approaches to improve the frequency stability of the FGs by using FFR services that will help policymakers to determine and improve the frequency performance of a low inertia power system.
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Nilsson, Fanny, Felicia Schützler, and Jennifer Sturedahl. "Preventing Inertia: Levaraging the Usage of Facebook as a Dynamic Capability." Thesis, Högskolan i Jönköping, Internationella Handelshögskolan, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-43950.
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Background – Inertia describes a state whereby companies develop slower relative the pace of change experienced by their environment, something most organizations experience at least once in their lifetime. Being in the state of inertia and consequently failing to adapt to change cause new businesses to replace old ones. Therefore, it is important for firms to be dynamic, which enables them to quickly recognize opportunities and threats. A way for companies to answer to these changes is to possess dynamic capabilities, which is found to be a solution for inertia. Digital innovation has played a key role in the evolution of dynamic environments. In order for companies to adapt to changing environments, the need for digital adaptation is becoming increasingly crucial. As a result, digital and social platforms have rapidly emerged throughout society, forcing companies to act to avoid stagnating in their development. Purpose - This thesis aims to analyze how the utilization of Facebook as a dynamic capability can prevent inertia through the microscope of the Dynamic Capability Framework. Method - Empirical data was collected through an interview study with employees at strategy and digital media consultancy firms. The participants possess extensive knowledge in the field of strategic implementation of social media. Primary data was gathered through semi-structured interviews and was analyzed in relation to the reviewed theory within inertia, dynamic capabilities, and digital innovation, by a thematic analysis. Findings - The findings of this thesis indicate that by dynamically utilizing Facebook, companies can extensively explore markets. This allows companies to continuously align existing resources by adapting and acting on identified trends within markets. Since these are actions within the Dynamic Capability Framework, a conclusion can be drawn that the usage of Facebook can be a dynamic capability. The usage of Facebook can therefore prevent organizations from entering the state of inertia. The findings further show that in order for the utilization of Facebook to be a dynamic capability, companies must possess extensive user skills and competencies. This research adds to the existing theory of digital media and business development by examining the usage of the social media platform, Facebook, through the lens of the Dynamic Capability Framework.
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El-Bordany, Refaat. "In orbit calibration of satellite inertia matrix and thruster coefficients." Thesis, University of Surrey, 2001. http://epubs.surrey.ac.uk/842840/.
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In this research study, several new in-orbit algorithms are proposed to improve the performance of Attitude Determination and Control System (ADCS) by estimating the inertia matrix and calibrating the cold gas thruster system of the UoSAT-12 spacecraft. Computer-based simulation models will be constructed using MATLAB and SIMULINK in order to evaluate the expected performance. The first focus is on the identification of the satellite inertia matrix. A new algorithm based on a Recursive Least Square (RLS) estimation technique is proposed for in-orbit use to estimate the inertia matrix (moments and products of inertia parameters) of a satellite. To facilitate this, one attitude axis is disturbed using a reaction wheel whilst the other two axes are controlled to keep their respective angular" rates small. Within a fraction of an orbit three components of the inertia matrix can be accurately determined. This procedure is then repeated for the other two axes to obtain all nine elements of the inertia matrix. The procedure is designed to prevent the build up of momentum in the reaction wheels, whilst keeping the attitude disturbance to the satellite within acceptable limits. It can also overcome potential errors introduced by unmodeled external disturbance torques and attitude sensor noise. The second focus is on a new algorithm for in-orbit use to calibrate thruster coefficients for thrust level and alignment, using three reaction wheel actuators. These algorithms will ensure robustness against modeling errors. The algorithms assume no prior knowledge of the thruster parameters and only an initial guess of the inertia matrix. It is proposed that this calibration can be used during normal mission conditions when the satellite is stabilised. The final goal of this research study was to apply the proposed algorithms in real-time. Firstly, the thruster calibration algorithm was tested on an air-bearing table. Finally, both thruster calibration and moment of inertia algorithms were tested using data generated by UoSAT-12 while in orbit. The practical estimation results proved the feasibility of proposed algorithms.
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Petkov, Vesselin P. "Fundamental issues in general relativity, inertia, gravitation and electromagnetic mass." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0004/NQ40303.pdf.
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Leontitsis, Vasileios. "Decentralisation reforms in Greece (1981-2008) : exploring inertia and change." Thesis, University of Sheffield, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.531173.
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Steinhardt, Emma Marie. "Energy methods for analyzing drag and inertia in cycling kinematics." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/105669.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2016.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 53-54).
A model was developed for measuring the drag and effects of inertia for a cyclist during a race. Professional cyclist data from the Tour de France was acquired for several athletes. The data contained elevation, distance, velocity, and power as a function of time. Rolling resistance, drag, inertial energy, and potential energy were then evaluated. An integral energy equation relating these terms to input power was developed. This is much more stable numerically than differential equations in the power and force equations. This formula gave excellent agreement with the theoretical assumption that inertial effects are negligible. Additionally, the measured drag agreed with wind tunnel results. This work is the first to extract drag data from a cyclist during actual race conditions. In the future, this evaluation of drag variation coupled with energy equations could lead to optimizing cycling strategy.
by Emma Marie Steinhardt.
S.B.
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Sun, Earl S. "Implementation of low thermal inertia injection molds using conformal passages." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/10728.
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Warmoth, Francis James. "Floor Vibrations: Girder Effective Moment of Inertia and Cost Study." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/41005.
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Studies on the effective moment of inertia of girders that support concrete slabs using joist seats as the horizontal shear connections, and a cost efficiency analysis comparing composite and non-composite floor systems that meet vibrations design standards, were conducted.
The first study was undertaken because over-prediction of girder effective moment of inertia was the suspected cause of several recent vibration problems in floors supported by widely spaced LH-series joists. Eight purpose-built floors of the type in question were subjected to experimental tests of girder effective moment of inertia and girder frequency. Frequencies were tested for two live loading cases. Three separate test configurations were made with each floor by changing the seat-to-girder connections between bolted, welded, and reinforced. In the study, 1) the accuracy of the current design practice is assessed, 2) a new relationship was proposed, and 3) suggestions for finite element modeling are made.
In recent years, composite construction has been used to improve cost efficiency by reducing structural weight and in some cases by reducing story height. However, vibration problems are a design consideration in composite floors because lighter floors tend to be more lively. It is not clear if cost savings can be made with composite construction if vibrations are considered in the design. To compare the cost of composite and non-composite floors that satisfy AISC/CISC Design Guide criterion for walking excitation, four typical size bays were analyzed using commercial design software that finds the least expensive member configuration for a given bay size. All acceptable bay configurations of member sizes and spacing were evaluated for least non-composite and composite costs, then these results were compared. The findings show that composite construction can be more economical when initial dead load deflections do not control the design.Master of Science