Dissertationen: „Sprung mass“

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Shimp, Samuel Kline III. „Vehicle Sprung Mass Parameter Estimation Using an Adaptive Polynomial-Chaos Method“. Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/32056.

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The polynomial-chaos expansion (PCE) approach to modeling provides an estimate of the probabilistic response of a dynamic system with uncertainty in the system parameters. A novel adaptive parameter estimation method exploiting the polynomial-chaos representation of a general quarter-car model is presented. Because the uncertainty was assumed to be concentrated in the sprung mass parameter, a novel pseudo mass matrix was developed for generating the state-space PCE model. In order to implement the PCE model in a real-time adaptation routine, a novel technique for representing PCE output equations was also developed. A simple parameter estimation law based on the output error between measured accelerations and PCE acceleration estimates was developed and evaluated through simulation and experiment. Simulation results of the novel adaptation algorithm demonstrate the estimation convergence properties as well as its limitations. The simulation results are further verified by a real-time experimental implementation on a quarter-car test rig. This work presents the first truly real-time implementation of a PCE model. The experimental real-time implementation of the novel adaptive PCE estimation method shows promising results by its ability to converge and maintain a stable estimate of the unknown parameter.
Master of Science

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Jaroš, Petr. „Konstrukce 1/4 modelu vozidla pro testy tlumičů“. Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2021. http://www.nusl.cz/ntk/nusl-442802.

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This thesis deals by the design of 1/4 car model for testing vehicle dampers, which can be used to simulate the real suspension of a vehicle wheel (up to a maximum car weight of 1,970 kg) and the so-called linear wheel suspension. A linear mathematical 1/4 car model with 2 DOF (Degrees Of Freedom) and data from literature search are used to design and derive the basic parameters of the device. The thesis contains a description of the linear mathematical model and its outputs (acceleration of the sprung mass and forces acting on the sprung mass), description of designed device, descriptions of created simulations (static, modal and harmonic analysis in ANSYS Workbench 2020 R2) and conceptual design of the modifications this device for another possible use for testing of bicycles.

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Harwood, Michael J. „Mass-spring modelling of vault springboard contact“. Thesis, Loughborough University, 1999. https://dspace.lboro.ac.uk/2134/7078.

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Vaulting is a discipline in Men's and Women's Artistic Gymnastics. While the springboard contact is not judged, the success of the rest of the vault is underpinned by it. The purpose of this study was to develop an understanding of the mechanics of the springboard contact phase of gymnastic vaulting. An analysis of hopping in place, forward hopping and running jumps on a force platform showed that the force-mass centre displacement relationship during ground contact approximated that of a mass rebounding on a linear spring. Subsequently, two mass-spring models were developed using a symbolic mathematics package. Both models represented the gymnast as a rigid cylinder, with personalized linear and angular inertia characteristics, connected at its mass centre to a linear spring. A one spring model combined the springiness of the gymnast and the springboard in a single linear spring, while a two spring model treated them as separate linear springs. Handspring vaults performed by an elite male gymnast at a range of approach speeds and springboard settings were analysed to provide model inputs. Springboard properties were empirically determined and revealed that the springboard stiffness varied appreciably depending upon feet contact position. Given the touchdown kinematics and takeoff angle of the gymnast, the models estimated spring stiffness and linear and angular takeoff velocities, the spring stiffness and takeoff vertical velocity estimates showing some sensitivity to spring angle at touchdown. Simulations in which the touchdown kinematics and spring stiffnesses were systematically adjusted, identified their influence on takeoff kinematics and provided an insight into the mechanics of springboard. contact. Estimated (leg) spring stiffnesses were consistent with those reported in the literature for other activities and'simulation results showed that simple rebounds accounted for the majority of the takeoff velocities. Spring angle at touchdown was found to be most effective at modifying each of the takeoff variables, however to produce a selective effect on takeoff required a combination of adjustments to the touchdown. In proposing strategies for gymnasts, their ability to control each of the touchdown variables has to be considered.

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Taminato, Rodrigo Luis. „Estudo quimico do Allium tuberosum Rottl. ex Spreng biomonitorado pela avaliação da atividade anti-Candida albicans“. [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/290221.

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Orientadores: Vera Lucia Garcia Rehder, Marta Cristina Teixeira Duarte
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
Made available in DSpace on 2018-08-06T20:58:10Z (GMT). No. of bitstreams: 1 Taminato_RodrigoLuis_M.pdf: 889161 bytes, checksum: 74c08f7f56d17f89884a6856839f1ba1 (MD5) Previous issue date: 2006
Resumo: De uso freqüente na medicina popular, o gênero Allium inclui mais de 600 espécies encontradas em diversas regiões do mundo como Europa, América do Norte, África e Ásia. A maioria das espécies é comestível e possui aroma e odor característicos, sendo também utilizadas como hipocolesterolêmico, antigripal e antimicrobiano. Alguns estudos de determinação das propriedades de Allium spp. como antifúngico e de identificação de seus compostos voláteis foram conduzidos. A maior parte de seus constituintes são compostos sulfurados, embora a composição química seja variável entre os diferentes estudos. Dentre as espécies de Allium spp., o A. tuberosum Rottl. ex Spreng (Liliaceae) pertence a mesma família do alho, cebola e alho-poró, é conhecido também como "Chinese chive", sendo um importante ingrediente na culinária asiática, também utilizado como erva medicinal para muitas disfunções e doenças. Na China é popularmente chamado de "Jiucai" e no Japão de "Nirá". Os óleos essenciais das folhas e bulbos deA. tuberosum obtidos por hidrodestilação em sistema do tipo Clevenger. As fases aquosas ou hidrolatos foram extraídas com diclorometano, obtendo-se o OB (óleo essencial dos bulbos) - 810 mg (0,12%) e o OF (óleo essencial das folhas) -750 mg (0,15%). O extrato dic1orometânico obtido dos bulbos - EB, obtido em sistema Ultra-Turrax, apresentou rendimento 3,28% (497 mg).O OB foi fracionado em coluna seca, utilizando como eluente dic1orometano. Foram obtidas, 8 frações (FI a F8), analisadas por CCD. As frações 3, 4 e 5 foram agrupadas resultando nas frações: FI - 138,6mg (33%), F2 - 15,3mg (3,7%), F3 - 13,6mg (3,3 %), F4 - 51,9 (12,6%), F5 - 34,lmg (8,3%), F6 - 31,2mg (7,6%). Analisados por CG-MS observa-se que a maioria dos compostos identificados nos óleos essenciais das folhas e bulbos e das frações obtidas do OB são compostos organosulfetos (COS). As principais classes de sulfetos identificadas nas diferentes amostras de A. tuberosum, destacam-se os monosulfetos, disulfetos, trisulfetos, tetrassulfetos e sulfinatos. Na avaliação do MIC obtiveram-se atividade do OB de 200ug/mL e das frações mais ativas FI (50ug/mL) e F2 (50ug/mL). Concluii-se que os principais compostos responsáveis pela atividade anti Candida albicans do Allium tuberosum são alil,metil-disulfeto, dimetil-trisulfeto, dialildisulfeto e alil,metil-trisulfeto, presentes no óleo essencial dos bulbos e nas frações FI e F2
Abstract: Frequently used in folk medicine, the genus Allium include more than 600 species founded in several world regions like Europe, North America, Africa and Asia. The most of species is edible and have a aroma and smell characteristics, being algo used as hypocholesterolemic, anticold and antimicrobial. Among theAllium species,A. tuberosum Rottl. ex Spreng (Liliaceae) belongs to the same family of the garlic, anion and poroallium. In the China, is popularly called "Jiucai" and in Japan, "Nirá" and is also know as "Chinese chive", a important ingredient in the Asiatic culinary. Studies aims determine the properties of Allium spp. as antifungical and aim identify their volatile compounds are described in literature. The essential oils from leaves (OF) and bulbs (OB) ofA. tuberosum were obtained by hydrodistillation in a Clevenger system, yielding 0,15% and 0,12%, respectively. The dichloromethanic extract from bulbs (EB), obtained in a Ultra-Turrax system, presented yield of 3,28%. The minimal inhibitory concentration (MIC) from oils against Candida albicans was: OF (>1000ug/mL), OB (200ug/mL) and EB (250ug/mL). The OB was fractionated in dry column by use of dichloromethane as eluent, when were obtairied six fractions: FI (33%), F2 (3,7%), F3 (3,3 %), F4 (12,6%), F5 (8,3%), F6 (7,6%), evaluated to anti-C. albicans activity. The volatile compounds present in the essential oils, extract and fractions of OB were identified by CG-MS. The major,ity compounds present in the OF, OB and in the FI and F2 from OB were organosulphides from disulphides classes, trisulphides, tetrasulphides and sulphinides, to standing out the allyl, methyl-disulphide, dimethyl-trisulphide, diallyl-disulphide and alil, methyl trisulphide. Significant quantities of limonene and sulphinades and low concentration of other sulphides were founded in EB. The MIC evaluation of fractions obtained from OB revealed a significant increase of activity for FI and F2, with MIC value of 50ug/mL, when compared to OB (200ug/mL). These results indicate that the main compounds from A. tuberosum responsible by anti-Candida activity are allyl, methyl-disulphide, dimethyltrisulphide, diallyl-disulphide and diallyl disulphide, present in higher concentration in OB and in the fractions FI e F2
Mestrado
Farmacologia, Anestesiologia e Terapeutica
Mestre em Odontologia

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Langenfeld, Jonathan Wayne. „Wave Propagation and Vibration of Spring-Mass Systems“. OpenSIUC, 2010. https://opensiuc.lib.siu.edu/theses/298.

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AN ABSTRACT OF THE THESIS OF JONATHAN WAYNE LANGENFELD, for the Master of Science degree in Mechanical Engineering and Energy Processes, presented on 28 October 2010, at Southern Illinois University Carbondale. TITLE: WAVE PROPAGATION AND VIBRATION OF SPRING-MASS SYSTEMS MAJOR PROFESSOR: Dr. Serge Abrate The main focus of this research was to study wave propagation and modeling techniques of spring-mass systems. The purpose is to show that by engineering a materials microstructure, the material can have wave filtering capabilities. Numerical solutions were obtained for the steady-state response of a uniform, alternating, and branched spring-mass chain. The spring-mass chains studied were excited by harmonic forces; it is shown how gaps exist in the frequency ranges which can be applied to the chain, to filter wave propagation. The spring-mass chains were modeled as a continuum being governed by the wave equation or higher order models such as Love's rod theory. It was concluded that the best agreement was found between the spring-mass chain and the continuum models when excited by very low frequencies. Transient response problems are addressed for uniform materials, sandwiched materials, laminates, and graded materials. Analytical solutions for the response to these problems are presented along with numerical solutions using the finite element method. Step and impulse loading cases are studied to monitor if and how the initial wave pulse distorts upon propagation through a material. Underwater blast loading cases are studied which model water as a uniform bar transmitting waves into the hull of a sea going vessel. Results are presented for one-dimensional cloaking scenarios. Cloaking models are created from basic two component models and increased to four component models. Analytical and numerical solutions are obtained proving that the magnitude of reflected waves can be reduced by gradually decreasing the wave speed with each added layer. All of the results obtained throughout this research agree that the microstructure of a material can be engineered to control wave propagation.

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Golec, Karolina. „Hybrid 3D Mass Spring System for Soft Tissue Simulation“. Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1004/document.

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La nécessité de simulations de tissus mous, tels que les organes internes, se pose avec le progrès des domaines scientifiques et médicaux. Le but de ma thèse est de développer un nouveau modèle générique, topologique et physique, pour simuler les organes humains. Un tel modèle doit être facile à utiliser, doit pouvoir effectuer des simulations en temps réel avec un niveau de précision permettant l'utilisation à des fins médicales. Cette thèse explore de nouvelles méthodes de simulation et propose des améliorations pour la modélisation de corps déformables. Les méthodes proposées visent à pouvoir effectuer des simulations rapides, robustes et fournissant des résultats physiquement précis. L'intérêt principal de nos solutions réside dans la simulation de tissus mous élastiques a petites et grandes déformations à des fins médicales. Nous montrons que pour les méthodes existantes, la précision pour simuler librement des corps déformables ne va pas de pair avec la performance en temps de calcul. De plus, pour atteindre l'objectif de simulation rapide, de nombreuses approches déplacent certains calculs dans une étape de pré-traitement, ce qui entraîne l'impossibilité d'effectuer des opérations de modification topologiques au cours de la simulation comme la découpe ou le raffinement. Dans cette thèse, le cadre utilisé pour les simulations s'appelle TopoSim. Il est conçu pour simuler des matériaux à l'aide de systèmes masses-ressorts (MSS) avec des paramètres d'entrée spécifiques. En utilisant un MSS, qui est connu pour sa simplicité et sa capacité à effectuer des simulations temps réel, nous présentons plusieurs améliorations basé physiques pour contrôler les fonctionnalités globales du MSS qui jouent un rôle clé dans la simulation de tissus réels. La première partie de ce travail de thèse vise à reproduire une expérience réelle de simulation physique qui a étudié le comportement du tissu porcin à l'aide d'un rhéomètre rotatif. Son objectif était de modéliser un corps viscoélastique non linéaire. A partir de l'ensemble des données acquises, les auteurs de l'expérience ont dérivé une loi de comportement visco-élastique qui a ensuite été utilisée afin de la comparer avec nos résultats de simulation. Nous définissons une formulation des forces viscoélastiques non linéaires inspirée de la loi de comportement physique. La force elle-même introduit une non linéarité dans le système car elle dépend fortement de l'amplitude de l'allongement du ressort et de trois paramètres spécifiques à chaque type de tissu. La seconde partie de la thèse présente notre travail sur les forces de correction de volume permettant de modéliser correctement les changements volumétriques dans un MSS. Ces forces assurent un comportement isotrope des solides élastiques et un comportement correct du volume quel que soit la valeur du coefficient de Poisson utilisé. La méthode nécessite de résoudre deux problèmes: l'instabilité provoquant des plis et les contraintes de Cauchy. Nos solutions à ces limitations impliquent deux étapes. La première consiste à utiliser trois types de ressorts dans un maillage entièrement hexaédrique: les arêtes, les faces diagonales et les diagonales internes. Les raideurs des ressorts dans le système ont été formulées pour obéir aux lois mécaniques de base. La deuxième étape consiste à ajouter des forces de correction linéaires calculées en fonction du changement de volume et des paramètres mécaniques du tissu simulé, à savoir le coefficient de Poisson et le module de Young [etc…]
The need for simulations of soft tissues, like internal organs, arises with the progress of the scientific and medical environments. The goal of my PhD is to develop a novel generic topological and physical model to simulate human organs. Such a model shall be easy to use, perform the simulations in the real time and which accuracy will allow usage for the medical purposes.This thesis explores novel simulation methods and improvement approaches for modeling deformable bodies. The methods aim at fast and robust simulations with physically accurate results. The main interest lies in simulating elastic soft tissues at small and large strains for medical purposes. We show however, that in the existing methods the accuracyto freely simulate deformable bodies and the real-time performance do not go hand in hand. Additionally, to reach the goal of simulating fast, many of the approaches move the necessary calculations to pre-computational part of the simulation, which results in inability to perform topological operations like cutting or refining.The framework used for simulations in this thesis is designed to simulate materials using Mass Spring Systems (MSS) with particular input parameters. Using Mass-Spring System, which is known for its simplicity and ability to perform fast simulations, we present several physically-based improvements to control global features of MSS which play the key role in simulation of real bodies

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Eriksson, Emil. „Simulation of Biological Tissue using Mass-Spring-Damper Models“. Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-27663.

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The goal of this project was to evaluate the viability of a mass-spring-damper based model for modeling of biological tissue. A method for automatically generating such a model from data taken from 3D medical imaging equipment including both the generation of point masses and an algorithm for generating the spring-damper links between these points is presented. Furthermore, an implementation of a simulation of this model running in real-time by utilizing the parallel computational power of modern GPU hardware through OpenCL is described. This implementation uses the fourth order Runge-Kutta method to improve stability over similar implementations. The difficulty of maintaining stability while still providing rigidness to the simulated tissue is thoroughly discussed. Several observations on the influence of the structure of the model on the consistency of the simulated tissue are also presented. This implementation also includes two manipulation tools, a move tool and a cut tool for interaction with the simulation. From the results, it is clear that the mass-springdamper model is a viable model that is possible to simulate in real-time on modern but commoditized hardware. With further development, this can be of great benefit to areas such as medical visualization and surgical simulation.
Målet med detta projekt var att utvärdera huruvida en modell baserad på massa-fjäderdämpare är meningsfull för att modellera biologisk vävnad. En metod för att automatiskt generera en sådan modell utifrån data tagen från medicinsk 3D-skanningsutrustning presenteras. Denna metod inkluderar både generering av punktmassor samt en algoritm för generering av länkar mellan dessa. Vidare beskrivs en implementation av en simulering av denna modell som körs i realtid genom att utnyttja den parallella beräkningskraften hos modern GPU-hårdvara via OpenCL. Denna implementation använder sig av fjärde ordningens Runge-Kutta-metod för förbättrad stabilitet jämfört med liknande implementationer. Svårigheten att bibehålla stabiliteten samtidigt som den simulerade vävnaden ges tillräcklig styvhet diskuteras genomgående. Flera observationer om modellstrukturens inverkan på den simulerade vävnadens konsistens presenteras också. Denna implementation inkluderar två manipuleringsverktyg, ett flytta-verktyg och ett skärverktyg för att interagera med simuleringen. Resultaten visar tydligt att en modell baserad på massa-fjäder-dämpare är en rimlig modell som är möjlig att simulera i realtid på modern men lättillgänglig hårdvara. Med vidareutveckling kan detta bli betydelsefullt för områden så som medicinsk bildvetenskap och kirurgisk simulering.

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Hrudík, Jan. „Přední náprava vysokovýkonného sportovního vozu“. Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-443475.

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Tato diplomová práce byla psána při studentské zahraniční stáži, pod záštitou Evropské Unie – program „ERASMUS Student Mobility for Placement“. Stáž byla absolvována mezi prosincem 2010 a květnem 2011 ve společnosti a.d.Tramontana, mající sídlo v Palau de Santa Eulália, Španělsko. Pro kompletní návrh podvozku a odpružení jakéhokoli vozidla je nezbytná znalost mnoha technických disciplín. Tato diplomová práce se zabývá dvěma z nich – odpružení a řízení. Nejprve je rozebrána teorie, na kterou se může navázat v praktické části práce. Velká pozornost byla věnována srozumitelnosti textu a názornosti obrázků, bez zbytečných detailů, avšak bez vynechání důležitého. Tuto práci je tedy možné užít jako prvního kroku před návrhem podvozku. V další části je popsáno, jak byla probraná teorie využita při návrhu řízení u skutečného vozu, přičemž největší pozornost je věnována Ackermannově teorii řízení a geometrii zabraňující samořízení při propružení. V závěrečných částech je pozornost věnována ukázce některých z každodenních činností v malosériové výrobě automobilů – jde o zjištění maximálně možného pohybu kola při propružení a proces výroby příčných trojúhelníkových ramen včetně návrhu jejich připevnění k šasi.

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Ojima, Hirotaka, Kenji Nagase und Yoshikazu Hayakawa. „Wave-based analysis and wave control of damped mass-spring systems“. IEEE, 2001. http://hdl.handle.net/2237/6856.

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Holt-Phoenix, Marianne S. (Marianne Shue). „Wave propagation in finite element and mass-spring-dashpot lattice models“. Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/35683.

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Thesis (Nav. E. and S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.
Includes bibliographical references (p. 42).
Numerical efficiency comparisons of a four-node finite element model (FEM), a mass-spring lattice model (MSLM), and a mass-spring-dashpot lattice model (MSDLM) are investigated. Specifically, the error in the ultrasonic phase speed with variations in Poisson's ratio and angle of incidence is evaluated in each model of an isotropic elastic solid. With regard to phase speed, materials with constant N grid spaces per P-wavelength having Poisson's ratios between 0.0 and 0.25 are modeled more accurately with the MSLM. Materials with Poisson's ratios between 0.35 and 0.5 and N grid spaces per P-wavelength are more accurately modeled with the FEM. Materials whose Poisson's ratio is between 0.25 and 0.35 are modeled equally accurately. With regard to phase speed, viscoelastic materials modeled with FEM and MSDLM show good agreement with known analytical solutions. The computational expense of all three models is also examined. The number of floating point operations (FLOPS) needed to achieve a specified phase speed accuracy is calculated for each different model. While the FEM and MSLM have nearly the same computation cost, the MSDLM is 5 times more costly than either the FEM or MSLM.
by Marianne S. Holt-Phoenix.
Nav.E.and S.M.

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Adegbola, Oluseyi. „U.S. television reporting of the Arab Spring| A study of ABC, CBS and NBC“. Thesis, University of Nebraska at Omaha, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10139262.

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Reporting of international conflict has implications for understanding, political action, and policy formation. This means media coverage can influence the outcomes of conflict. This study investigated reporting of the Arab Spring conflicts by U.S. television networks (ABC, CBS, and NBC). The study examined the time frame between the onset of the uprising and February 29, 2012 when dictators were unseated in Tunisia, Egypt, Libya, and Yemen. Agenda-setting and media framing theory were used to analyze transcripts (N = 316) for dominant issues, sources used, frames and, social media. Results of the study corroborate existing research regarding conflict reporting. Coverage was mostly episodic and dominated by violence, however, attention was paid to the role of social media in overthrowing regimes, violent acts of regime brutality, and democracy. Core causes of the uprising received only marginal coverage. Ordinary domestic citizens were used most frequently as sources. Other findings applicable to U.S. media coverage are presented.

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Van, Tol Zachary Charles. „Analysis of Urban Heat Island Intensity Through Air Mass Persistence“. Thesis, Virginia Tech, 2021. http://hdl.handle.net/10919/103468.

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The bulk of synoptic weather type research related to urban climate focuses on human health impacts; however, recent studies have begun to quantify urban heat island (UHI) magnitudes by weather type, or air mass classification. This study presents an analysis of UHI intensity through synoptic-scale air mass persistence during the spring season for four UHI-prone United States cities. Historical daily weather types for Birmingham, Alabama; Charlotte, North Carolina; Louisville, Kentucky; and St. Louis, Missouri were extracted from the Spatial Synoptic Classification database for 40 years from 1980 through 2019. Daily minimum surface air temperature data were downloaded from the Global Historical Climate Network to compute UHI. The historical daily weather type data were converted into a record of persistence, or the length of consecutive days that a synoptic weather type was in place at each location. A descriptive climatology of SSC weather types and UHI at each location was constructed before UHI magnitudes were segregated by day of persistence and examined for differences in intensity. Climatologically, the four urban areas experienced an increase in warm weather types at the expense of cool weather types throughout the study period. Specifically, the persistence of moist tropical weather types increased at a statistically significant rate at Birmingham, Charlotte, and Louisville, consistent with the theorized northward migration of the mid-latitude jet stream. Also evident is a statistically significant increase in UHI frequency and intensity at Birmingham, Charlotte, and Louisville during the study period. Results show that the moisture character of a weather type is an important differentiating factor in UHI intensification, as the mean UHI was found to increase with the persistence of dry weather types and decrease with the persistence of moist weather types, presumably reflecting differences in radiational heating and cooling with atmospheric moisture content. The most intense UHIs and the largest UHI magnitude increase by day of persistence are associated with dry weather types, which have become more frequent since 1980. The findings suggest that larger magnitude UHIs may become more common in the future should dry weather type persistence continue to increase. Higher urban temperatures put human health at risk due to a well-linked relationship between heat and mortality and morbidity rates. The effects of heat are cumulative; the more common persistent, oppressive days become, the larger the impact.
Master of Science
Most of the research related to variation in the warmth of an urban area relative to the surrounding rural area, or the urban heat island (UHI) effect, under varying air mass conditions (temperature and humidity) has focused on human health impacts. This study examines UHI intensity through regional-scale air mass persistence during the spring season in four UHI-prone United States cities. Historical daily air mass conditions in the form of weather types for Birmingham, Alabama; Charlotte, North Carolina; Louisville, Kentucky; and St. Louis, Missouri were downloaded from the Spatial Synoptic Classification database for the 40 years from 1980 to 2019. UHI values for each urban location were calculated using daily minimum air temperature data from the Global Historical Climate Network. A descriptive climatology of weather types and UHI magnitude at each of the four urban locations established long-term means and trends before analysis of UHI intensity through varying weather type residence times, or persistence. Time series analyses align with previous indications of an increasing persistence of weather types and an increase in the frequency of warm weather types at the expense of cool weather types during the spring season. An increase in both UHI frequency and intensity occurred through the study period at Birmingham, Charlotte, and Louisville. The mean intensity of the UHI was found to increase with the persistence of weather types of low humidity and to decrease with the persistence of moist weather types. The largest mean UHI and the largest UHI magnitude increase by day of persistence are associated with low humidity weather types, which have become more frequent since 1980. The impacts of heat are cumulative; persistently elevated temperatures are detrimental to human health.

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Deymier, Pierre, und Keith Runge. „One-Dimensional Mass-Spring Chains Supporting Elastic Waves with Non-Conventional Topology“. MDPI AG, 2016. http://hdl.handle.net/10150/615109.

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There are two classes of phononic structures that can support elastic waves with non-conventional topology, namely intrinsic and extrinsic systems. The non-conventional topology of elastic wave results from breaking time reversal symmetry (T-symmetry) of wave propagation. In extrinsic systems, energy is injected into the phononic structure to break T-symmetry. In intrinsic systems symmetry is broken through the medium microstructure that may lead to internal resonances. Mass-spring composite structures are introduced as metaphors for more complex phononic crystals with non-conventional topology. The elastic wave equation of motion of an intrinsic phononic structure composed of two coupled one-dimensional (1D) harmonic chains can be factored into a Dirac-like equation, leading to antisymmetric modes that have spinor character and therefore non-conventional topology in wave number space. The topology of the elastic waves can be further modified by subjecting phononic structures to externally-induced spatio-temporal modulation of their elastic properties. Such modulations can be actuated through photo-elastic effects, magneto-elastic effects, piezo-electric effects or external mechanical effects. We also uncover an analogy between a combined intrinsic-extrinsic systems composed of a simple one-dimensional harmonic chain coupled to a rigid substrate subjected to a spatio-temporal modulation of the side spring stiffness and the Dirac equation in the presence of an electromagnetic field. The modulation is shown to be able to tune the spinor part of the elastic wave function and therefore its topology. This analogy between classical mechanics and quantum phenomena offers new modalities for developing more complex functions of phononic crystals and acoustic metamaterials.

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Shiva, V. A. „Visualization of wave propagation in elastic solids using a mass-spring lattice model“. Thesis, Massachusetts Institute of Technology, 1989. http://hdl.handle.net/1721.1/63194.

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Thesis (M.S.V.S.)--Massachusetts Institute of Technology, Dept. of Architecture, February 1990.
Videocassette is VHS format.
Includes bibliographical references.
by Shiva Ayyadurai.
M.S.V.S.

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Silva, Josildo Pereira da. „A Data-Driven Approach for Mass-Spring Model Parametrization Based on Continuous Models“. Instituto de Matemática, 2015. http://repositorio.ufba.br/ri/handle/ri/22848.

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Nowadays, the behavior simulation of deformable objects plays important roles in several fields such as computer graphics, computer aided design, computer aided surgery And robotics. The two main categories of deformable models are: based on continuum mechanics, like Finite Element Model (FEM) or Isogeometric Analysis (IGA); and using discrete representations, as a Mass - Spring Model (MSM). FEM methods are known for their high computational cost and precision, while MSM methods, although simple and affordable for real-time applications, are di cult to parameterize. There is no general physically based or systematic method in the literature to determine the mesh topology or MSM parameters from a known material. Therefore, in this thesis, we proposea methodology to parametrize the MSM based on continuous models with focus on the simulation of deformable objects in real-time for application in virtual environments. We developed two data-driven approaches to the parametrization of the MSM by using FEM and IGA models as reference of derivation with higher order elements. Based on experimental results, the precision achieved by these new methodologies is higher than other approaches in literature. In particular, our proposal achieves excellent results in the parametrization of the MSM with higher order elements which does not occur with other methodologies
Atualmente, a simula¸c˜ao de objetos deform´aveis desempenha papel importante em v´arios campos ligados `a Ciˆencia da Computa¸c˜ao, como a computa¸c˜ao gr´afica, projeto assistido por computador, cirurgias assistidas por computador e rob´otica. Nesse contexto, a simula¸c˜ao de objetos deform´aveis com acur´acia e em tempo-real ´e uma tarefa extremamente dificil para as aplica¸c˜oes que requerem simula¸c˜oes mecˆanicas interativas como s˜ao os casos dos ambientes virtuais, simuladores cir´urgicos e jogos. Podemos dividir as abordagens que d˜ao suporte ao tratamento de modelos deform´aveis em dois grandes grupos: baseados em mecˆanica do cont´ınuo, como M´etodo de Elementos Finitos (FEM - Finite Element Method) ou An´alise Isogeom´etrica (IGA - Isogeometric Analysis); e usando representa¸c˜oes discretas, como modelo massa-mola (MSM - Mass Spring Model). M´etodos baseados na abordagem cont´ınua s˜ao conhecidos por seu alto custo computacional e acur´acia, enquanto que os m´etodos discretos, embora simples e adequados para simula¸c˜oes mecˆanicas interativas, s˜ao dif´ıceis de parametrizar. A falta de um m´etodo geral baseado em f´ısica ou sistem´atico para determinar a topologia de malha ou os parˆametros do MSM a partir de um material conhecido foi a principal motiva¸c˜ao desse trabalho, no sentido de gerar um modelo de baixo custo computacional, como o MSM, a partir de um modelo de alta precis˜ao como o FEM. Portanto, partindo da premissa de simplicidade e adequa¸c˜ao do MSM para simula¸c˜oes mecˆanicas interativas, nesta tese propomos uma metodologia para parametrizar o MSM baseada em modelos cont´ınuos. Desenvolvemos duas abordagens orientadas `a dados (data-driven) para a parametriza¸c˜ao do MSM usando modelos FEM e IGA, este ´ultimo como referˆencia de deriva¸c˜ao com elementos de ordem superior. Com base nos resultados experimentais, a precis˜ao alcan¸cada por estas novas metodologias ´e mais elevada do que a de outros trabalhos similiares na literatura. Em particular, a nossa proposta alcan¸ca excelentes resultados na parametriza¸c˜ao do MSM com elementos de ordem superior

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Alhujaili, Fahad Abdulrahman. „Semi-Active Control of Air-Suspended Tuned Mass Dampers“. University of Dayton / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1354480214.

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Turner, Kimberly Noel. „EDUCATION BULGES AND MASS PROTEST: HOW HIGHER EDUCATION INFLUENCES PROTEST ONSET AND OUTCOMES“. OpenSIUC, 2021. https://opensiuc.lib.siu.edu/dissertations/1951.

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AN ABSTRACT OF THE DISSERTATION OFKimberly Noel Turner, for the Doctor of Philosophy degree in Political Science, presented on June 9, 2021, at Southern Illinois University Carbondale. TITLE: EDUCATION BULGES AND MASS PROTEST: HOW HIGHER EDUCATION INFLUENCES PROTEST ONSET AND OUTCOMESMAJOR PROFESSOR: Dr. Stephen BloomCan trends in higher education attainment explain protest onset and outcomes? Beneficial state development indicators, such as education attainment, may produce detrimental employment outcomes. Nonviolent protests spread throughout the developing world throughout the 2010s, often in countries previously immune to public agitation. At the forefront of these protests were well-educated professionals, often doctors and lawyers. Why did these protests emerge? Why did middle-class groups initiate and lead these protests? How successful were these protests? The education bulge theory provides a framework for explaining the onset and outcomes of nonviolent mass protests in repressive countries. The education bulge theory captures the formation of skilled labor grievance and the spillover that influence the emergence of nonviolent, large and diverse protests. Chapter Two details the education bulge theory. Education bulges occur when a country undergoes sharp increases in university enrollments exceeding global averages. As university graduates increases, so does the supply of skilled labor. An increasing percentage of the population is then impacted when demand for skilled labor wanes, i.e. skills downgrading. Skills downgrading worsens the relative position of university graduates to other educational attainment groups, increasing tertiary unemployment and underemployment. Skilled labor compensates by downshifting, seeking out and competing for positions within the semi-skilled job market. This increased competition for semi-skilled positions pushes other educational groups down and out of the labor market. The global forces of labor polarization, education bulges, and skills downgrading are examined for their roles in inducing downshifting behavior. The fomentation of grievance amongst skilled labor is detailed, as well as the spillover effects for semi and unskilled labor. Flattening supplies of knowledge-intensive positions within the private sector along with public sector hiring reductions in the post-recession period exacerbates the decline of skilled labor’s relative position. Chapter Three examines objective measures of skilled labor’s relative position to other education attainment groups. Alongside theories of economic development and inequality, the education bulge theory is tested for its relationship to protest onset. Governmental expenditures on education, relative unemployment amongst primary, secondary and tertiary education attainment groups, and average wage growth are evaluated for their relationship with education bulges and protest onset. Bivariate and multivariate regression analysis indicate that skills downgrading is significantly increases the odds of protests emerging in highly repressive countries. Under an education bulge, additional governmental spending on tertiary education is positively correlated to protest onset. Do education bulges contribute to the overall successfulness of protests? In Chapter Four, I develop a new cost-benefit approach to measuring protest success. Canonical binary measurement of protest success fails to capture the relative concessions demonstrators might extract from their regimes. I develop a 21-point scale capturing the dimensions of gains protests might achieve (in the form of regime concessions) and the costs they pay for those concessions (in the form of state reprisals). Using Mokken scale analysis, country success scores pinpoint a protest’s position along a unidimensional continuum of abject failure to transformative changes in the body politic is developed. My measure offers an improved method of capturing regime behavior in the form of ‘ignoring’ and active repression. My measure also captures instances where protests may be misclassified as failures and features a stronger correlation for crowd age diversity. However, the success scores and binary measures often share directionality and strength for key causal factors. Thus, I cannot claim a definitive victory for my measure. However, unlike binary measures, my measure is able to offer more accurate confidence intervals for interactive relationships evaluated in Chapter Five. Chapter Five evaluates the relationship between political contexts and protest features. Entrenched leadership and repressive state structures are traditional deterrents to protest success. Education bulges, leadership tenure, and state repressiveness are evaluated for their influence on protest successfulness. Education bulges are found to increase overall protest successfulness. Education bulges are also found to increase crowd size and crowd diversity. Interactive relationships between education bulges, crowd size, and class diversity are examined. Class diversity and education bulges are individual have a positive and significant influence upon protest success. Education bulges are found to moderate class diversity, shifting class diversity’s effect on protest success from positive to negative. Regime concessions and protest successfulness are also influenced by external factors, such as sanctions, defections, and audience sympathy. External actors are more likely to apply reputational, material or defection costs against regimes when protests occur within education bulges and feature class diversity. These costs act as mediators of regime responsiveness. Under a mediated moderation model, the direct and indirect effect of education bulges, crowd size, class diversity, and regime costs are evaluated for their effect on protest successfulness. Education bulges increase reputational costs for regimes while class diversity increases material costs. Crowd size increased both material costs and defections. Education bulge contexts producing diverse and large crowds are more successful than non-education bulge protests. This study offers an examination of the role of higher education attainment upon the emergence and successfulness of nonviolent mass protests in authoritarian states from 2005-2013. Despite data limitations, robust findings indicate that education bulges increase the odds of a stable repressive regime experiencing protest onset and protest success. Failure of central governments to ensure commiserate employment for their growing pools of skilled labor increases grievance, crowd sizes and diversity, and punitive action against governments seeking to repress demonstrators.

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Ojima, Hirotaka, Kenji Nagase und Yoshikazu Hayakawa. „A study on the impedance matching controller for uniformly varying damped mass-spring systems“. IEEE, 2003. http://hdl.handle.net/2237/6858.

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Parkin, John D. „Microcantilevers : calibration of their spring constants and use as ultrasensitive probes of adsorbed mass“. Thesis, University of St Andrews, 2013. http://hdl.handle.net/10023/3608.

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The dynamic properties of several rectangular and V-shaped microcantilevers were investigated. Particular attention was paid to the higher flexural eigenmodes of oscillation. The potential of the higher flexural modes was demonstrated through the use of cantilevers as standalone sensors for adsorbed mass. The mass adsorbed on the surface of a cantilever was in the form of a homogeneous water layer measured as a function of relative humidity. The minimum detectable water layer thicknesses were 13.7 Å, 3.2 Å, 1.1 Å, and 0.7 Å for the first four modes of a rectangular cantilever, clearly demonstrating enhanced accuracy for the higher eigenmodes of oscillation. These thicknesses correspond to minimum detectable masses of 33.5 pg, 7.8 pg, 2.7 pg and 1.7 pg for the first four modes. For quantitative applications the spring constants of each cantilever must be determined. Many methods exist but only a small number can calibrate the higher flexural eigenmodes. A method was developed to simultaneously calibrate all flexural modes of microcantilever sensors. The method was demonstrated for the first four eigenmodes of several rectangular and V-shaped cantilevers with nominal fundamental spring constants in the range of 0.03 to 1.75 N/m. The spring constants were determined with accuracies of 5-10 %. Spring constants of the fundamental mode were generally in agreement with those determined using the Sader method. The method is compatible with existing AFM systems. It relies on a flow of gas from a microchannel and as such poses no risk of damage to the cantilever beam, its tip, or any coating. A related method was developed for the torsional modes of oscillation. Preliminary results are shown for the fundamental mode of a rectangular cantilever. The method can be easily extended to the higher torsional modes, V-shaped cantilevers, and potentially, the flapping modes of the legs of V-shaped microcantilevers.

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Wu, Albert. „The Theory, Implementation, and Evaluation of Spring Mass Running on ATRIAS, a Bipedal Robot“. Research Showcase @ CMU, 2017. http://repository.cmu.edu/dissertations/926.

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We expect legged robots to be highly mobile. Human walking and running can execute quick changes in speed and direction, even on non-flat ground. Indeed, analysis of simplified models shows that these quantities can be tightly controlled by adjusting the leg placement between steps, and that leg placement can also compensate for disturbances including changes in the ground height. However, to date, legged robots do not exhibit this level of agility or robustness, nor is it well understood what prevents them from attaining this performance. This thesis begins to bridge the gap between the theoretical motions of simplified models and the implementation of agile behaviors on legged robots. The state of the art allows room for improvement at the level of the simplified model, at the level of hardware demonstration, and at the level of theoretical understanding of applying the simplified model to a real system. We make progress on each of these facets of the problem as we work towards leveraging theory from the simplified model to generate effective control for locomotion on robots. In particular, spring mass theory has identified deadbeat stability for planar running, but it must be formulated in 3D to be applicable to a real system. We extend this behavior to 3D, adding deadbeat steering to the tracking of apex height on unobserved terrain. Running robots have yet to demonstrate the agile and robust behavior that the spring mass model describes; existing implementations do not target the deadbeat behavior. We apply state of the art control techniques to map the deadbeat stabilized planar running onto our robot ATRIAS, and we successfully demonstrate tight tracking of commanded velocities and robustness to unobserved changes in ground height. Despite this empirical proof of concept, it remains unclear how exactly the targeted behavior of the simplified model affects the closed loop behavior of the full order system. There are additional degrees of freedom which affect the tracking of original goals and additional layers of control which may offer other sources of stability. Furthermore, the hardware introduces perturbations and uncertainties which detract from the nominal performance of the full order model. To answer these questions, we formulate a framework founded on linear theory, and we use it to examine the contributions of each component of the control and to quantify the expected effects of the disturbances we encounter. This analysis reveals insights for effective control strategies for legged locomotion and presents a tool for scientific iteration between theory-based control design and evidence-based revision of the underlying theory.

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Juma, Hameed W. „Numerical and Experimental Analyses of Actively Controlled Pendulum Tuned Mass Damper“. University of Dayton / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1544528950528469.

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Carvalho, Janaina Tobias de. „Comportamento dinâmico das lajes flutuantes de vias permanentes em sistemas metroferroviários“. Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-21052015-115006/.

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A preocupação com o impacto ambiental decorrente da implantação e operação de novas linhas metroferroviárias faz com que na elaboração dos projetos de via permanente sejam frequentemente adotados sistemas amortecedores de vibrações e ruídos secundários. As vibrações em vias de metrô são causadas principalmente pelo contato roda-trilho e são propagadas pela estrutura do túnel e pelas distintas camadas de solo podendo chegar às edificações lindeiras, onde, dependendo da intensidade, provocam desconforto aos usuários da edificação e mau funcionamento de equipamentos. Uma solução de atenuação largamente empregada atualmente em locais críticos é o \"sistema massa mola\". O sistema \"massa mola\" é composto por lajes de concreto armado, denominadas lajes flutuantes, apoiadas sobre materiais resilientes. De forma geral, quanto menor a frequência natural deste sistema, maior a atenuação das vibrações. No entanto, a utilização de apoios excessivamente flexíveis para obtenção de baixas frequências pode acarretar problemas operacionais em função de deslocamentos e acelerações excessivos das lajes flutuantes. Este projeto tem como objetivo o estudo do comportamento dinâmico das lajes flutuantes de concreto armado utilizadas em sistemas \"massa mola\" principalmente com relação à atenuação de vibrações e nível de vibrações na via permanente durante a passagem dos trens metropolitanos. A avaliação foi realizada utilizando modelos numéricos calibrados com dados experimentais obtidos nas linhas do Metrô de São Paulo.
Deploying and operating subway lines cause growing concern about environmental impact, making necessary in new lines projects the adoption of damping systems for no propagation of noise and vibration arising from traffic from trains. The vibrations in a subway track are mainly caused by wheel-rail contact and are propagated by tunnel structure and soil layers, reaching the neighboring buildings and causing annoyance residents in building. Equipment failures represent a consequence as well. A mitigation solution widely employed in critical locations is the known \"mass spring system\". The \"mass spring system\" system is composed of reinforced concrete slabs, so called floating slabs, resting on resilient materials. In general, greater attenuation of vibrations can be attained with lower natural frequency of system. However, the use of flexible supports for obtaining excessively low frequencies can cause operational problems due to excessive accelerations and displacements of the floating slab. This project aims to study the dynamic behavior of reinforced concrete floating slabs used in systems\' mass spring particularly with respect to mitigating vibrations and level of vibrations during the passage of the commuter trains. The evaluation was performed using numerical models calibrated with experimental data obtained in the lines of the São Paulo Metro.

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Ricks, Colin Rodger. „Quantifying Mass Sediment Movement in Deer Creek Reservoir During Spring Runoff and Potential Water Quality Impacts“. BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2880.

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The accurate prediction of water quality is essential for management of reservoirs used for drinking water supply. Since algae are a major source of taste and odor problems in drinking water, understanding and controlling algal growth and production is an important task. Deer Creek Reservoir supplies drinking water for over one million people in northern Utah and has been highly eutrophic in the past. Despite major reductions in external nutrient loading, including phosphorus, seasonal algal blooms in Deer Creek have not decreased to desired levels. Resuspension of sediment has been suggested as a potential source of internal nutrient loading for water bodies (including reservoirs in the Utah/Wyoming area) and may be responsible for delays in water quality improvement. I investigated sediment deposition and resuspension rates at the upper end of the reservoir and evaluated these sediments as a possible internal source of phosphorus. Sonar and GPS systems were used to make measurements of recently deposited sediment in the submerged Provo River delta of Deer Creek Reservoir during the period of May, June, July, and August 2011. ArcGIS 10 was used to interpolate survey points and calculate sediment volume changes, including areas of deposition and erosion. These data were used to develop approximate sedimentation rates for the soft sediment – which is most susceptible to resuspension during reservoir drawdown. I used previously measured field phosphorous concentrations in the sediment to estimate if these processes could affect reservoir phosphorous concentrations. The study used two survey areas, a small area near the Provo River inlet early in the year, and an extended larger area starting on June 23rd. I found that sediment volume in the smaller study area was increasing at a rate of 27-109 m3/day during the spring season. Data show that rates are slightly correlated with flow and reservoir elevation. Typically by August, Deer Creek reservoir would have been drawn down 2 to 4 m. However, due to a heavy snow pack in 2011, Deer Creek reservoir was not drawn down. When the reservoir is drawn down, the sediments in the upper region of the delta, where the survey was conducted, will be resuspended and deposited lower in the reservoir. These processes will likely result in releasing the phosphates currently bound to the sediment into the water column. Based on previous measurements of readily soluble phosphates bound to the sediment, this resuspension could release between 80 and 230 kg of phosphorus from the study area into the water column during critical times during the warm months–conditions well suited for algal growth. This amount of phosphorus, while an upper bound of what could be expected under actual field conditions, could raise phosphorus concentrations in the survey area by as much as 0.38 mg/L. The potential P (80-230 kg) release could account for 14%-42% of the TMDL. This is a potentially significant amount, especially if released during the critical late-summer period, and warrants more detailed study.

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Santos, Artur Bonezi dos. „Avaliação da estabilidade no exercício long stretch front do pilates“. reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2018. http://hdl.handle.net/10183/184652.

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A estabilidade do tronco é geralmente desafiada nas sessões do método Pilates. A compreensão da estabilidade/instabilidade, desafiada pela alteração de molas e dependente do nível de treinamento dos executantes, possui grande impacto no controle do tronco. Após uma revisão sistemática foi possível verificar que a principal técnica biomecânica empregada para compreender a estabilidade do tronco é a modelagem. Sendo assim, o objetivo deste estudo foi desenvolver e avaliar um modelo biomecânico para quantificar e comparar a estabilidade do tronco em dois diferentes níveis de praticantes de Pilates e em dois diferentes níveis de intensidade do exercício long stretch front do Pilates. O exercício long stretch front, criado para utilizar o powerhouse e desafiar a estabilidade do tronco, é executado no aparelho reformer na posição de prancha e consiste na extensão de ombros. O movimento foi modelado como um sistema massa-mola sendo a rigidez (K) o parâmetro de estabilidade do tronco. Como dados de entrada foram utilizadas informações cinemáticas, de câmeras infra-vermelho, cinéticas, de células de carga acopladas ao equipamento reformer, e informações antropométricas extraídas da literatura. Foram avaliados 15 praticantes avançados de Pilates e 15 iniciantes. Os indivíduos mais experientes foram mais estáveis durante o exercício do que iniciantes, F(1,28)=7,965; η2=0,22; p=0,009. A execução dos exercícios com duas molas apresentou menor rigidez do que com uma única mola, F(1,28)=67,891; η2=0,71; p<0,001. Não houve interação entre os fatores, F(1,28)=0,587; η2=0,02; p=0,450. Quando os grupos foram comparados separadamente para cada um dos níveis de dificuldade, os mais experientes (K = 272 ± 27 Nm/rad) apresentaram maior rigidez que os iniciantes (K = 171 ± 42 Nm/rad) com uma única mola, e também com o uso de duas molas, com K = 196 ± 17 Nm/rad para os executantes experientes e K = 108 ± 21 Nm/rad para os executantes iniciantes. Conclui-se que o modelo proposto, utilizando o coeficiente de rigidez, foi capaz de quantificar a estabilidade durante o exercício longh stretch front do Pilates. O modelo também identificou as diferenças entre indivíduos mais ou menos experientes, bem como quando o exercício é executado com uma ou com duas molas.
Trunk stability is usually challenged during Pilates method ’sessions. The stability/instability, generated by altering springs or by the practitioner’s experience level during a Pilates exercise, has great impact in trunk control. Following a systematic review, it was observed that modelling is the main biomechanical technique applied for understanding trunk stability. Hence, this study aimed to develop and evaluate a biomechanical model for quantifying and compare trunk stability in two different Pilates practitioners levels and two different intensities of the exercise during Pilates’ long stretch front exercise. The long stretch front exercise, created for using the powerhouse and challenging trunk stability, is performed in the reformer apparatus, keeping the trunk in the plunk position while shoulder extension is performed. The movement was modelled as a spring-mass system using stiffness (K) as the parameter to express trunk stability. Model input consisted of kinematics data, obtained from infrared cameras images, kinetic data, from load cells attached to the reformer equipment, and anthropometric data, obtained from literature. Fifteen experienced and 15 beginner Pilates practitioners, who performed ten repetitions of the exercise in two difficulty levels, with one and two springs, were evaluated. Experienced subjects were more stable during the exercise when compared to beginners F(1.28)=7.965; η2=0.22; p=0.009. The exercise performed using two springs presented a lower rigidity level when compared to one spring F(1.28)=67.891; η2=0.71; p<0.001. There was no interaction between the factors , F(1.28)=0.587; η2=0.02; p=0.450. When groups were compared separately for each difficulty level, experienced (K=272 ± 27 Nm.rad-1) presented higher rigidity than beginners (K=171 ± 42 Nm.rad-1) using one spring, and also using two springs with K=196 ± 17 Nm.rad-1 for experienced performers and K=108 ± 21 Nm.rad-1 for beginners. Concludes that the proposed model is capable of quantifying stability during the Pilates long stretch front exercise using rigidity coefficient. In addition model identifies differences between more or less experienced subjects, as well as when the exercise is performed using one or two springs.

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Alajmi, Fawaz M. „FROM "INDEXING" OFFICIALS TO "INDEXING" THE PUBLIC: KUWAITI NEWSPAPERS AGENDA BUILDING, NEWS INDEXING AND TWITTER USE IN KARAMAT WATAN PROTESTS, 2012“. OpenSIUC, 2015. https://opensiuc.lib.siu.edu/dissertations/1024.

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MAJOR PROFESSORS: DR. UCHE ONYEBADI & DR. KATHERINE T. FRITH This dissertation was conducted to determine whom the Kuwaiti newspapers indexed in their news reports during the Karamat Watan protests, and how Twitter influenced the indexing process. This study also examined how and why Twitter affected Kuwaiti journalists' agenda building process during their coverage of the protests. For the purpose of this study, the theoretical framework was the indexing model and the agenda building theory. To answer the research questions and hypothesis in this dissertation the researcher used a mixed method approach, comprising the quantitative content analysis of Kuwaiti newspapers and qualitative in-depth interviews with Kuwaiti journalists. The content analysis results show that Kuwaiti newspapers indexed more public views than official views in their coverage of the Karamat Watan protests and the number of non-official sources is larger than the number of official sources in the coverage of the event- driven news. Also, the analysis shows that during the protests the independent newspapers indexed more public views than the semi- official newspapers in Kuwait. Furthermore, the interviews show that Kuwaiti journalists were not unanimous in their opinions regarding the role of twitter in their agenda building process during the protests. While some of them believed that twitter was a good tool that helped them in their coverage of the protests in particular and other events in general, others said that it was hard to be confident about the credibility of the online sources.

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Knuth, Jordan Marie. „The Effects of Microorganism on Carbonate Precipitation in the Ten Mile Graben Cold Springs, Utah: A Mars Analog“. OpenSIUC, 2018. https://opensiuc.lib.siu.edu/theses/2385.

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Biosignatures have been extensively studied at hot springs sites, such as Yellowstone, because liquid water is fundamental to the existence of life but also owing to the influx of mineral nutrients in these environments. However, some hot springs have upper temperatures exceeding the boundaries capable of sustaining life in all the spring facies, particularly those nearest the vent. Cold springs provide the same nutrient-rich environment with more ambient temperatures potentially capable of sustaining a diverse consortium of microorganisms across the entirety of the system. Ten Mile Graben Cold Springs, located in Southern Utah, is one such site known for its biota and preservation potential. This study aimed to observe the possible effects of the microorganisms on aragonite and calcite precipitation. Scanning electron microscope imagery observed biogenic fabric such as botryoidal aragonite and aragonite microspheres; however, the δ13C enrichment values of +2.80‰ to +7.30‰ imply the springs were dominantly precipitated through CO2 degassing. This discrepancy in the chemical and morphological data has been observed at other astrobiology analog sites such as Yellowstone; therefore, travertine and tufa seemingly do not preserve isotopic chemical biosignatures.

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Hall, Anthony R. „The Pseudo-Rigid-Body Model for Fast, Accurate, Non-Linear Elasticity“. BYU ScholarsArchive, 2013. https://scholarsarchive.byu.edu/etd/3869.

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We introduce to computer graphics the Pseudo-Rigid-Body Mechanism (PRBM) and the chain algorithm from mechanical engineering, with a unified tutorial from disparate source materials. The PRBM has been used successfully to simplify the simulation of non-linearly elastic beams, using deflections of an analogous spring and rigid-body linkage. It offers computational efficiency as well as an automatic parameterization in terms of physically measurable, intuitive inputs which fit naturally into existing animation work flows for character articulation. The chain algorithm is a technique for simulating the deflection of complicated elastic bodies in terms of straight elastic elements, which has recently been extended to incorporate PRBM beam-elements in three dimensions. We present a new, mathematically equivalent optimization of the 3D PRBM chain algorithm, from its former asymptotic complexity of O(n^2) in the number of elements n, to O(n). We also extend an existing PRBM for combined moment-force loads to 3D, where the existing 3D PRBM chain algorithm was limited to 3D PRBM elements for a moment-only load. This optimization and extension are validated by duplicating prior experimental results, but substituting the new optimization and combined-load elements. Finally, a loose road-map is provided with several key considerations for future extension of the techniques to dynamic simulations.

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MARTÍN, DE AZCÁRATE LAURA. „Muscle contributions to body mass center acceleration during the first stance of sprint running“. Thesis, KTH, Mekanik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-250027.

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The best results in a sprint running are based upon covering the distance in the shortest possible time, and therefore performance has to be maximized. To achieve the best performance, the sprinter has to develop the greatest forward acceleration, reach his/her maximal speed, and keep it over the run. The greatest anteroposterior acceleration is generated in the first stance of a sprint due to the greatest propulsive force production. Thus, the first step was selected to study induced accelerations by the main muscles of the lower limb. Since a wider step width was founded out to help with force generation during long foot-ground contacts, an elite sprinter with a wide step width was selected. Ankle plantarflexors were the main contributors to body propulsion and support, while knee extensors decelerated forward propulsion but induced medial accelerations. Hip extensors and hip adductors did not offer a remarkable contribution to body COM acceleration in any direction.

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Ren, Li. „Imagining China in the Era of Global Consumerism and Local Consciousness: Media, Mobility, and the Spring Festival“. Ohio : Ohio University, 2003. http://www.ohiolink.edu/etd/view.cgi?ohiou1057001670.

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Merker, Andreas [Verfasser], Martin [Akademischer Betreuer] Hermann, Andre [Akademischer Betreuer] Seyfarth und Gerhard [Akademischer Betreuer] Zumbusch. „Numerical bifurcation analysis of the asymmetric spring-mass model / Andreas Merker. Gutachter: Martin Hermann ; Andre Seyfarth ; Gerhard Zumbusch“. Jena : Thüringer Universitäts- und Landesbibliothek Jena, 2014. http://d-nb.info/1058858025/34.

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Campos, Ricardo Silva. „Modelagem eletromecânica do coração com autômato celular e sistemas massa-mola“. Universidade Federal de Juiz de Fora, 2016. https://repositorio.ufjf.br/jspui/handle/ufjf/1772.

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CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico
Este trabalho apresenta o simulador FisioPacer, que é um simulador que reproduz a propagação do pulso elétrico pelo tecido cardíaco e a sua deformação mecânica. Foi utilizado um autômato celular acoplado a um sistema massa-mola para que as simulações sejam realizadas rapidamente. Foi também utilizado um algoritmo genético para automaticamente determinar parâmetros do modelo de forma a reproduzir outros experimentos in silico e o comportamento de um ventrículo real. Com intuito de validar o modelo foram feitos setenta e dois experimentos e os resultados foram comparados com outro simulador robusto, baseado em equações diferenciais. As comparações mostraram que o FisioPacer reproduziu satisfatoriamente o comportamento do tecido, sendo até quinze mil vezes mais rápido. Além disto, foram simuladas as funcionalidades eletromecânicas de um ventrículo esquerdo a partir de dados de um paciente, obtidos via ressonância magnética.
This work proposes a computational heart model named FisioPacer, which aims to reproduce the electrical pulse propagation over the cardiac tissue and its mechanical deformation. In order to perform fast simulations, it was used a cellular automaton coupled with a mass-spring system. A genetic algorithm was also used to automatically adjust model parameters, in order to reproduce in silico experiments and a real left ventricle behavior. For the model validation, seventy two experiments were performed and the results were compared to another robust simulator, based on partial differential equations. The comparisons showed that the FisioPacer simulator could reproduce cardiac tissue electromechanics, with up to 15000-fold improvement in computational time. Furthermore, a real patient left ventricle was simulated, with data obtained via MRI.

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Villeger, David. „Restitution d'énergie élastique et locomotion (REEL) : une approche adimensionnelle“. Toulouse 3, 2014. http://thesesups.ups-tlse.fr/4068/.

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L'objectif de ce travail est de développer une approche adimensionnelle de la locomotion humaine, et plus précisément de la marche et de la course. En d'autres termes, le principal enjeu de cette thèse est d'induire des similitudes locomotrices entre des hommes de tailles différentes. Ces similitudes locomotrices attendues entre des individus de différentes tailles sont les mêmes que celles que les physiciens recherchent lors de l'élaboration de prototype à partir de maquette. Dans l'approche que nous tentons de développer tout au long de ce document, nous considérons qu'un individu petit est le modèle réduit d'un plus grand. Notre approche est au croisement des champs de la physique, de la modélisation et de la biomécanique. L'application de l'analyse dimensionnelle aux modèles simples de locomotion permet de mettre en avant l'intérêt des nombres adimensionnels de Froude (vitesse adimensionnelle) et Strouhal (fréquence adimensionnelle) pour étudier la locomotion humaine. Ces modèles simples de locomotion simplifient le corps humain à la masse du corps concentrée au centre de gravité oscillant à l'extrémité d'un ressort. Ils prennent en compte une composante élastique et mettent en avant des transferts se réalisant au centre de gravité entre les énergies cinétique, potentielle de pesanteur et potentielle élastique. Le rapport de ces énergies est appelé Modela. Modela possède deux variantes, une pour la marche et l'autre pour la course, et est dépendant de Froude et Strouhal. Dans un premier temps, les conditions expérimentales de vitesse de déplacement (à partir de Froude) et de fréquence de pas (à partir de Strouhal), toutes deux relatives à l'anthropométrie des individus, ont permis d'engendrer des similitudes locomotrices pour la marche et la course chez des individus de tailles différentes. Ces résultats révèlent tout l'intérêt d'une approche adimensionnelle de la locomotion en montrant qu'exprimés indépendamment de l'anthropométrie des individus, leurs comportements adimensionnels est le même. Utiliser cette approche pour comparer des locomotions au sein même de l'espèce humaine a un grand intérêt pour étudier des comportements déviants d'un comportement standard. Aussi, cette approche peut être un moyen de mettre en avant des organisations du mouvement communes à différentes espèces. Dans un second temps, l'accent est mis sur la comparaison entre le modèle simple et le modèle complexe du corps humain. D'un coté, le modèle simple du corps humain prend en compte une composante élastique et ne s'intéresse qu'au centre de gravité. De l'autre coté, le corps humain peut être modélisé comme un ensemble de segments corporels articulés entre eux. Ici, un lien est fait entre le mouvement global du centre de gravité et les coordinations des segments poly-articulés, lors du mouvement, et tout ce que cela engendre en termes de transfert d'énergie. Le rapprochement des deux modèles explique comment un individu peut se comporter comme une masse bondissante lors de la marche et la course ou comment les expérimentations futures pourront investir le champ de l'élasticité humaine et de l'économie d'énergie
The aim of this paper is to develop a dimensionless approach of the human locomotion, and more specifically of walking and running gaits. In other terms, the main goal of this PhD thesis is to induce locomotor similarity between different-sized humans. These similarities are the same that the physicians look for when they design a prototype from a scale model. Throughout the thesis paper, this approach allows the consideration that a small human is a reduced model of a tall one. Our approach is cross-fielded like Physics, Modelization, and Biomechanics. The dimensional analysis application to the common locomotion models allows to highlight the interest of using the dimensionless numbers of Froude (dimensionless speed) and Strouhal (dimensionless frequency) to study human locomotion. These locomotion models are reduced to the body mass represented at its center of mass oscillating at the end of a massless spring. They take into account an elastic component and enlighten transfers occurring at the center of mass between the kinetic, potential and elastic energies. The ratio of these energies is called Modela. A Modela corresponds to both walking and running, and depends on Froude and Strouhal. First, the experimental conditions such as speed displacement relative to anthropometry (from Froude) and step frequency relative to anthropometry (from Strouhal) allow us to generate locomotor similarity between different-sized subjects for walking and running. These results reveal the interest of the dimensionless approach of the locomotion by showing that the dimensionless behaviors are the same when they are expressed independently of the subject anthropometry. The use of this approach to compare human locomotions is interesting to study behavior different to the gold dimensionless standard. Also, this approach may be a means to highlight a global organization of the movement which is common to many species. Then, the comparison between the simple model and the complex model is investigated. In one hand, the model takes into account an elastic component and only describe the center of mass movement. In the other hand, the human body is represented as a whole of body segment poly-articulated. A link is done between the global movement of the center of mass and the movement of the poly-articular model, and especially regarding for the energy transfers. The link between the models explain how a subject has the same behavior of a spring mass, and how the future works will be able to investigate the fields of the human elasticity and the saving energy mechanisms

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Mahal, Bhopinder Singh. „The application of three-dimensional mass-spring structures in the real-time simulation of sheet materials for computer generated imagery“. Thesis, Heriot-Watt University, 2010. http://hdl.handle.net/10399/2359.

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Despite the resources devoted to computer graphics technology over the last 40 years, there is still a need to increase the realism with which flexible materials are simulated. However, to date reported methods are restricted in their application by their use of two-dimensional structures and implicit integration methods that lend themselves to modelling cloth-like sheets but not stiffer, thicker materials in which bending moments play a significant role. This thesis presents a real-time, computationally efficient environment for simulations of sheet materials. The approach described differs from other techniques principally through its novel use of multilayer sheet structures. In addition to more accurately modelling bending moment effects, it also allows the effects of increased temperature within the environment to be simulated. Limitations of this approach include the increased difficulties of calibrating a realistic and stable simulation compared to implicit based methods. A series of experiments are conducted to establish the effectiveness of the technique, evaluating the suitability of different integration methods, sheet structures, and simulation parameters, before conducting a Human Computer Interaction (HCI) based evaluation to establish the effectiveness with which the technique can produce credible simulations. These results are also compared against a system that utilises an established method for sheet simulation and a hybrid solution that combines the use of 3D (i.e. multilayer) lattice structures with the recognised sheet simulation approach. The results suggest that the use of a three-dimensional structure does provide a level of enhanced realism when simulating stiff laminar materials although the best overall results were achieved through the use of the hybrid model.

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Yamashita, Daichi. „The mechanics of human sideways locomotion“. Kyoto University, 2014. http://hdl.handle.net/2433/188791.

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Kyoto University (京都大学)
0048
新制・課程博士
博士(人間・環境学)
甲第18353号
人博第666号
新制||人||160(附属図書館)
25||人博||666(吉田南総合図書館)
31211
京都大学大学院人間・環境学研究科共生人間学専攻
(主査)准教授神﨑素樹, 教授森谷敏夫, 准教授久代恵介, 教授小田伸午
学位規則第4条第1項該当

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Oliveira, Suzana Matos FranÃa de. „SimulaÃÃo de malha triangular: um estudo sobre a adaptatividade da malha“. Universidade Federal do CearÃ, 2013. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=9839.

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CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior
A animaÃÃo de tecido vem sendo estudada abundantemente nas Ãltimas dÃcadas por haver demanda na indÃstria do entretenimento bem como no comÃrcio eletrÃnico de roupas. Esse tipo de animaÃÃo, na maioria das vezes, Ã feita com base em simulaÃÃo fÃsica, havendo muito gasto computacional. Esse trabalho tenta usufruir de vÃrios modelos para diminuir esse gasto. Ã feito uma modelagem do tecido com uma malha triangular e usa-se um modelo massa-mola-amortecedor para simular as forÃas entre as partÃculas, que sÃo os vÃrtices dessa malha. Dependendo da disposiÃÃo do modelo do tecido e dos objetos da cena, sÃo detectadas colisÃes entre eles. A malha Ã discretizada ou simplificada, levando em consideraÃÃo a compressÃo, a colisÃo e a curvatura das molas, para que seja usada uma malha boa em cada passo ao longo da animaÃÃo. Portanto, o objetivo principal desse trabalho Ã estudar o comportamento do tecido utilizando o modelo de remalhamento para adaptar essa malha.
In the last decades, cloth animation has been the focus of much research, due to demands from the entertainment industry and from e-commerce. That type of animation is most often the result of a physics-based simulation and has a great computational cost. This work investigates how to reduce the computational cost of the simulation, by refining the mesh only in regions that need a fine level of detail. The fabric model consists of a triangular mesh and uses a spring-mass-damper system to compute the forces among the particles, which are located at the meshâs vertices. The collision detection depends on the arrangement of the cloth model and the objects in the scene. The mesh is refined or simplified, taking into account the spring compression, collision and curvature, so the simulation uses a better mesh every time step. Therefore, this workâs main objective is to study the dynamic behavior of cloth, using a remeshing procedure in order to adapt the mesh.

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Stubblefield, Andrew T. „Coupled oscillations the reproduction and analysis of the oscillatory modes of a string/spring/mass pendulum and the derivation of the theoretical equations governing the motion of the mass ; an honors thesis /“. [Jefferson City, Tenn. : Carson-Newman College], 2009. http://library.cn.edu/HonorsPDFs_2009/Stubblefield_Andrew_T.pdf.

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Berggren, Rickard. „Cellulose degradation in pulp fibers studied as changes in molar mass distributions“. Doctoral thesis, KTH, Fibre and Polymer Technology, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3499.

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In this thesis, size-exclusion chromatography (SEC) of woodpolymers dissolved in lithium chloride/N,N-dimethylacetamide(LiCl/DMAc) has been used to characterize the molar massdistributions (MMD) of wood polymers in pulp fibers afterchemical degradation.

Characterization of birch kraft pulps subjected to ozonedegradation and acid hydrolysis, respectively, rendereddifferent changes in the MMD. Ozone degradation resulted inlarge redistributions of the original MMD, observed as thedevelopment of a distinct fraction of cellulose withintermediate molar mass. Acid hydrolysis resulted in minorchanges of the original MMD compared to ozonation. Fiberssubjected to acid hydrolysis were considerably weaker thanozonated fibers. These results indicated that there aredifferences in how the two chemicals degrade the fiber.

The solubility of softwood kraft pulp fibers was enhanced byderivatization of the fiber polymers with ethyl-isocyanateduring simultaneous dissolution in LiCl/DMAc. Thederivatization made it possible to achieve reliable estimationsof the MMD, and hence molar masses, of softwood kraft pulps.The derivatization procedure made it possible to dissolve 90 %of softwood kraft pulps with kappa numbers over 50.

Severe alkaline degradation of birch and Norway spruce woodchips was studied both by varying the pulping time and byvarying the initial alkali concentration. Differences werefound in the MMD of the two fiber types, and the alkalinedegradation was found to affect polymers in the entire MMD.

Multi-angular laser light scattering (MALLS) was used as adetection technique with SEC on cellulosic samples. The MMD andaverage molar masses obtained through directstandardcalibration with commercial standards were compared with MMDand molar masses as obtained by MALLS-detection. Largediscrepancies were found, and two methods of correcting forthese discrepancies were developed.

Theoretical simulations of polymer degradation wereperformed. Random, or homogeneous degradation was used as amodel for alkaline cellulose chain scission, and a resemblancewith experimental data was observed. End-wise depolymerizationof cellulose was also simulated and the results are discussedin the light of experimentally observed MMD.

Keywords:cellulose, kraft pulp, birch, spruce,ozonation, acid hydrolysis, degradation, MMD, sizeexclusionchromatography, light scattering, molar mass, chainscission

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Nilsson, Linus. „Real-time simulation of diaphragm displacement during physiological and mechanical ventilation“. Thesis, Uppsala universitet, Avdelningen för beräkningsvetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-202329.

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This thesis presents a tunable 3D real-time interactive simulator of the geometrical displacement of the thoracic diaphragm during physiological and mechanical ventilation. Particular attention is placed on capturing the heterogeneous tissue composition while maintaining computational efficiency and accuracy. The long term goal is to establish an accurate theoretical model to complement the experimental and clinical studies of the side effects associated with mechanical ventilation and to overcome the ethical difficulties of performing time resolved studies on human patients. The deformations are modelled using a commercial 3D model and a mass-spring model together with distance constraints and Verlet integration. The simulator is easily adjusted in real-time to many different cases of ventilation and validated through inspection and comparison with existing models. More research is needed to validate the model using patient specific data, as well as extending the model to include additional physiological and pathophysiological components. Long term goals includes considering the microscopic aspects of cellular mechanics to capture the underlying causes of ventilator-induced diaphragmatic dysfunction.

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ADIBHATLA, GAGAN. „DESIGN AND IMPLEMENTATION OF A COMPLIANCE CONTROLLER FOR THE PA10-7CE SEVEN DEGREE OF FREEDOM DEXTEROUS ROBOT“. University of Cincinnati / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1195870314.

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Hlaváč, Martin. „Návrh centrálních pružicích jednotek náprav Formule Student“. Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-377462.

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This master’s thesis deals with use of central spring unit at Formula Student car. Thanks to CFD simulations, aerodynamics properties of the car was found out according to different position of suspended mass. Within kinematic design of both axles a parameters of spring unit of both axles were defined as well. Whole design was made to increase overall performance of the car thanks to the aerodynamic forces.

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Alhayek, Katty. „Activism, Communication Technologies, and Syrian Refugees Women's Issues“. Ohio University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1417784369.

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Provazníková, Jana. „Mnichov jako legitimizační prostředek normalizace v ČSSR. Příspěvek k vlivu masových médií v ČSSR v 70. letech 20. století“. Master's thesis, Vysoká škola ekonomická v Praze, 2012. http://www.nusl.cz/ntk/nusl-162601.

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This magister thesis is focused on relationships between mass media, political power and society in Czechoslovakia in the late 60' and in the beginning of 70' in 20th century and desribe the transformation of media atmosphere during the era of political changes in Czechoslovakia, that means the transformation from "liberalized" 60' due to the normalization. I find answers to these questions: What were the most important changes in medial atmosphere in the Czechoslovakia in late 60' and beginning of 70'? Were media and politics connected? How important was the influence of mass media due to the political changes and normalization? Did comunists mass medias have such great power to influence society and persuade people about the rightness of intervention? As a main hypothesis there is the claim, that mass media under the comunists influence wanted to and actually managed to manipulate with people and their opinions. The answers for questions and hypotesis are verified on the basis of a general theory of media history and studies and then specifically analyzed on the concete historical example -- Munich Treaty. Methodologically this work come out of the new political history and discussion that lead to the role of mass media in modern sotieties, and also from the latest scientific literature and archival materials.

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Walinga, Charlotte P. „The Effects of Changing Spring Temperatures on Fuel Use, Mass Loss, Emergence Time, and Chill Coma Recovery in Solitary Mason Bees (Osmia spp.)“. Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/34502.

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Repeated cold exposures and warmer winter temperatures might negatively affect insects by depleting stored fuel reserves. I researched the effects of fluctuating thermal regimes on two species of solitary mason bees (Osmia albiventris and O. lignaria) by quantifying mass loss and reserves of lipids, free sugars, and glycogen after experimental temperature treatments during early spring. In a second season, I quantified mass loss, time to emergence, and time to recover from chill coma after bees had been exposed to one of two spring-time temperature regimes. I found that warmer temperatures in combination with greater temperature variability increases mass loss and the depletion of fuel reserves. Additionally, my results suggest that accelerated bee emergence helps to mitigate mass loss. Overall, these bees appear resilient in the face of changing spring temperatures. Résumé: On sait peu sur la façon dont la variabilité environnementale affecte les abeilles solitaires sauvages. Ma recherche a étudié la façon dont les régimes thermiques fluctuants affectent la vigueur de deux espèces d'abeilles solitaires (Osmia albiventris et O. lignaria) en quantifiant la perte de masse ainsi que les réserves métaboliques (lipides, sucres libres, et glycogène) des abeilles suite à des manipulations expérimentales de la température printanière. Dans une deuxième saison, j’ai quantifié la perte de masse, le temps de l'émergence et le temps pour récupérer du coma froid après que les abeilles avaient été exposées à l'un de deux régimes de températures printanières. Mes résultats indiquent que les températures plus chaudes ont tendance à augmenter la perte de masse et des réserves métaboliques lorsqu'elles sont combinées avec une plus grande variabilité. De plus, mes résultats suggèrent que ces abeilles sont résilientes face aux températures printanières changeantes.

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Andersen, Dale T. „Perennial springs in the Canadian High Arctic“. Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=85116.

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The search for extraterrestrial life begins with understanding how life developed and evolved on our own planet. Earth's polar regions provide a unique setting conducive to developing the methodologies and techniques that will be needed to find new life forms either as living organisms or as some biological signal in a sedimentary record.
The highest latitude perennial spring system in a region of thick, continuous permafrost resides in the Arctic archipelago of northern Canada. At Expedition Fiord on Axel Heiberg Island there are two sets of springs that provide useful analogs to liquid water habitats that may have existed on Mars. The springs occur in a region with a mean annual air temperature of -15.5° C. Spring flow rates and discharge temperatures are constant throughout the year. Filamentous bacteria, biofilms and mineral precipitates occur in association with the emergent, anoxic brine flowing from the springs.
Preliminary data on the microbial composition of the spring water has been obtained by applying the culture-independent approach. The majority (76%) of the fifty-five environtaxa showed high sequence similarity to Thiomicrospira species (sulfur-oxidizing organism). Other sequences show high similarity to sulfate-reducing members of the delta (Desulfocapsa sp.) and epsilon (Sulfurospirillum sp.) proteobacterium groups. A single sequence was found to have 99% sequence similarity to species of the genus Haloanaerobium a group of low G+C Gram positive, anaerobic, halophiles (Rainey et al. 1995).
A combined flow and thermal model of the Axel Heiberg springs has demonstrated how such springs are able to persist throughout the year despite temperatures that fall to below -50°C during the winter darkness. Dissolved gases emanating from the springs provide evidence of the origin of the water for the springs as well as placing constraints upon the residence time. The gas is composed primarily of N2 with relative concentrations of Ar, Kr, and Xe almost identical to air. No O2 is detectable and Ne is 60% of air values. We believe that ~50% of this gas originates from the direct release of air by nearby alpine glaciers and local ice sheets into groundwater that infiltrates sub-ice sedimentary deposits.

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Norberg, Samuelsson Lina. „Isoconversional analysis for the prediction of mass-loss rates during pyrolysis of biomass“. Doctoral thesis, KTH, Energiprocesser, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-187469.

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Biomass is the only renewable carbon source that can compete with fossil energy sources in terms of production of materials, chemicals and fuels. Biomass can be transformed into charcoal, liquid and gas through pyrolysis, i.e. pure thermal decomposition. By changing the pyrolysis conditions either solid, liquid or gaseous fractions can become the main product and pyrolysis is thus a very versatile process. Pyrolysis is also the first step in combustion and gasification, two important thermal processes in our society. The importance of biomass pyrolysis has led to extensive research in this area but due to the complexity of the process there is still no general understanding of how to describe biomass pyrolysis, which is essential in order to optimize thermal processes. The research presented in this thesis thus aims at finding a simple yet accurate way to model the decomposition rate of biomass during pyrolysis. Thermogravimetric analysis, a well known method that is simple to use, was chosen to collect the experimental data used for kinetic evaluation. The reaction kinetics were derived using two different model-free, isoconversional methods, i.e. the non-linear form of the Friedman method and the incremental, integral method ofVyazovkin. By using these two methods and experimental data, complete reactionrate expressions could be derived for commercial cellulose, Norway spruce and seven different samples originating from kraft cooking, the most common process to produce pulp for the paper industry. The derivation of model-free rate expressions have never been performed before for these materials and since the rate expressions are model-free, no assumptions or knowledge about the pyrolysis reactions were required. This is a great advantage compared to the commonly used model-fitting methods that rely on information about these aspects. All therate expressions were successful in predicting mass-loss rates at extrapolated pyrolysis conditions. This is a clear indication of the soundness of the methodologypresented in this thesis.
Biomassa är den enda förnybara kolkällan som kan konkurrera med fossila energikällor när det gäller produktion av material, kemikalier och bränslen. Biomassakan omvandlas till biokol, bioolja och gas med hjälp av pyrolys, dvs termisk nedbrytning. Genom att variera de processförhållanden som råder under pyrolysen kan man få antingen fast, flytande eller gasfasiga ämnen som huvudprodukt, något som gör pyrolys väldigt flexibelt. Utöver detta är pyrolys även betydelsefull vid förbränning och förgasning, två viktiga processer i dagens samhälle. Vikten av biomassapyrolys har resulterat i omfattande forskning inom området men pga biomassas komplexa natur råder det ännu ingen enighet gällande hur biomassapyrolys bör modelleras. Detta försvårar utveckling och optimering av termiska processer matade med biomassa. Forskningen som presenteras i denna avhandling fokuserar således på att finna en enkel men noggrann metod för att beskriva hastigheten med vilken biomassa bryts ned under pyrolys. Termogravimetrisk analys, en vanligt förekommande metod som är enkel att använda, valdes för att samla in experimentell data som kan användas för att undersöka hastigheten för termisk nedbrytning, dvs kinetiken. Två olika metoder som på engelska går under benämningen “model-free” och “isoconversional” har använts, nämligen den icke-linjära formen av Friedmans metod och den stegvisa, integrala metoden som utvecklats av Vyazovkin. Genom att använda dessa två metoder och experimentell data kunde kompletta reaktionshastighetsuttryck tas fram för kommersiell cellulosa, gran och sju olika material framställda genom sulfatprocessen, den idag vanligast förekommande pappersmassaprocessen. Pyrolyskinetiken för dessa material har aldrig tidigare analyserats med dessa två metoder och fördelarna med metoderna gjorde det möjligt att bestämma hastighetsuttryck utan någon kunskap om de pågående reaktionerna. Detta är en viktig fördel jämfört med andra metoder som är beroende av sådan information. Alla framtagna reaktionshatighetsuttryck kunde användas för att framgångsrikt förutsäga minskningen av massa vid extrapolerade pyrolysförhållanden. Detta är en tydlig indikation på att metoden använd i denna avhandling fungerar väl.

QC 20160524

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Larouche, Rémy. „Extraction, caractérisation et biotransformation de la lignine de Klason extraite de l'épinette blanche Picea glauca (Moench) Voss /“. Thèse, Chicoutimi : Université du Québec à Chicoutimi, 1993. http://theses.uqac.ca.

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Trouvain, Guillaume. „Evolution des outils de simulation rapide du procédé de fabrication du pneumatique avant cuisson“. Thesis, Clermont-Ferrand 2, 2015. http://www.theses.fr/2015CLF22546/document.

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Ces travaux de thèse s’intéressent aux outils de simulation rapide de la fabrication d’un pneumatique. L'objectif est de prédire le mouvement et la position des éléments constitutifs du pneumatique, lors de leur mise en conformation, en prenant en compte les déformations induites par les actions mécaniques associées. Ces travaux s’appuient sur la mise en place d’un algorithme visant à modéliser le gonflement d’un outillage et la mise en place d’un modèle de déformation d’un système de formes géométriques aux caractéristiques mécaniques différentes. L'algorithme de gonflement de l’outillage se base sur la théorie des membranes inextensibles et son industrialisation est validée pour des dimensions standards de pneumatiques. La méthode Masse-Ressort est retenue pour réaliser la déformation de formes géométriques afin d’obtenir des résultats de déformation en temps réel. Dans ces travaux, cette méthode est adaptée aux matériaux d’un pneumatique à partir de travaux de caractérisations géométrique et mécanique validés par comparaison aux Éléments Finis. En conclusion, la modélisation développée permet une description à chaque étape du procédé de fabrication
This thesis deals with fast simulation tools used to manufacture of a tire. The goal is to predict the displacement and position of the components of a tire taking into account the deformations induced by the associated mechanical actions. This work is based on the implementation of an algorithm for modeling the inflation of a tool and the development of a deformation model in order to compute the deformation of geometric shapes taking into account different mechanical properties. The algorithm to model the inflation of the tool is based on the theory of inextensible membranes and its industrialization is validated for standard sizes of tires. Mass-Spring method is used to achieve the deformation of geometric shapes in order to compute deformation in real time. In this work, this method is suitable for materials of a tire from geometric and mechanical characterizations validated by comparison with FEM. To conclude, the developed modelization allows a description for each step of the manufacturing process

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Brown, Connie J. „Mapping A Generation: Oral History Research in Sulphur Springs, FL“. Scholar Commons, 2004. http://purl.fcla.edu/fcla/etd/SFE0000295.

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Kalina, Martin. „Modelování tlumících zařízení v interakci s konstrukcí“. Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-226468.

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The aim of my master’s thesis was to create models of the damping device and observing their behavior in interaction with the structure. First was the construction separately modeled with Java application named FyDiK2D like a model with one degree of freedom. Model of construction takes form like a high, thin rod with full circular cross section. The lower part was restrained into the subsoil. The design was to verify the correct functionality of the model by comparing the analytical and numerical solutions. For capturing the precise behavior of the structure was converted to a multi-stage model. Then the pendulum damper was applied on this construction and found amplitude lies in highest point of multi-stage model. He was then replaced by tuned mass damper. By comparing these amplitudes from both dampers was found which kind of damper is efficient for multi-stage model.

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Gangidine, Andrew. „Trace Element Concentrations in Microbial Fossils as a Novel Biosignature for Life on Ancient Earth and Beyond“. University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1584015501312535.

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Dissertationen zum Thema „Sprung mass“

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