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”Den här är trä och den här är med trä, då kan den bara åka så där!” : Att tillämpa ett undersökande arbetssätt för förskolebarns lärande om fysikaliska fenomen utifrån det lutande planet / “This one is made of wood and this one is also made of wood, so it can only roll like that!” : Applying an investigative approach to preschool children's learning about physical phenomena based on the inclined planeBergqvist, Emily January 2024 (has links)
The purpose of the study is to contribute with knowledge of how an investigative approach can assist children of different ages in acquiring new knowledge and reinforcing existing knowledge about the falling motion of various artifacts based on an inclined plane. Eight children participated in the study, from three different age-divided departments. The starting point of the activity was inspired by the Reggio Emilia philosophy's thoughts on the unfinished material, where the children were asked to examine the fall movement of four different artefacts along an inclined plane. The observation is based on Predict, observe, explain scientific methodology. In the initial discussions, the children were asked to formulate hypotheses about the various artefacts’ motion along the incline, and then test and observe the phenomenon. The activity ended with reflections on their experiences about the practical elements. The study studied how the children in different ages acted and expressed themselves during the activity. The analysis is based on Piaget's stage theory and Vygotsky's view of learning about how children mediate knowledge. The results show that the children have a good ability to express themselves to try to explain and understand different physical phenomena such as friction, force and speed based on their own conditions. However, the ability to reflect differs between the different ages. The children aged 5–6 years show not only the ability to formulate hypotheses but also to explain their hypotheses, where they link their explanations to the shape of the object. At the same time, the younger children thought outside the box and explored the phenomenon of friction thoroughly. A crucial role is how the educator formulates his or her questions to develop the children's lifelong learning. / Syftet med studien är att bidra med kunskap om hur det undersökande arbetssättet kan hjälpa barn i olika åldrar att erövra nya kunskaper och förstärka befintlig kunskap kring olika artefakters fallrörelse utifrån ett lutande plan. I studien deltog åtta barn i åldern 2–6 år som delades in utifrån tre olika grupper baserat på förskolans åldersindelade avdelningar. Aktivitetens utgångspunkt var inspirerad av Reggio Emilia filosofins tankar om det ofärdiga materialet där barnen, med hjälp av ett lutande plan och fyra olika artefakter, fick undersöka fallrörelsen. Observationerna bygger på Predict, observe, explain naturvetenskapliga metodik. Barnen fick i de inledande diskussionerna formulera hypoteser om de olika artefakternas rörelse utmed planet, för att sedan pröva och observera fenomenet. Aktiviteten avslutades med reflektioner om deras upplevelser. I studien undersöktes hur barnen i olika åldrar agerade och uttryckte sig under aktiviteten. Analysen baseras på Piaget stadieteori och Vygotskijs syn på lärande om hur barn medierar kunskap. Resultatet visar att barnen har en god förmåga att uttrycka sig för att försöka förklara och förstå olika fysikaliska fenomen som friktion, kraft och hastighet, utifrån sina egna förutsättningar. Däremot skiljer sig barnens reflektionsförmåga beroende på ålder. Barnen i åldrarna 5–6 år visar inte bara förmågan att formulera hypoteser utan också att ge en förklaring till sina hypoteser, där de kopplar sina förklaringar till föremålets form. Samtidigt som de yngre barnen tänker utanför boxen och utforskar fenomenet friktion grundligt. En avgörande roll är hur pedagogen formulerar sina frågor för att utveckla barnens livslånga lärande.
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Dynamic Simulations of Compact Gearbox for RobotsUrasim, Muhammad January 2024 (has links)
This thesis project is conducted in collaboration with Swepart Transmission AB, aimed to dynamically simulate the compact gearbox design with planetary gears meant to be used in robots. The primary objective of this project is to analyze operational principles of planetary gears and their suitability for mitigating lost motion (backlash). Simulations have been carried out using MSC Adams software where the input speed is 1400 rpm on the pinion gear, which is equal to 1100 deg/s when applied to the sun gear. An adjustment gear is mounted atop sun gear, which is used to adjust the position of the planet gears and it is locked with different variations of 0, 5 and 10 degrees of angular displacement to adjust the planet gears. Additionally, one of the planet gears is selected and the position of teeth in that planet gear is deviated by 10, 20, 30 and 40 micrometers and these new gears are then placed in position of the existing planet gear one by one. These models are then simulated to study the variations and effects of angular velocity on the ring gears, angular velocity of the adjustment gear, displacement in radial direction of the planet gear after it is adjusted, force and torque generated on contact between the planet gear and the ring gear over a period of 5 seconds using 1000 time steps.
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Design and analysis of terrain adapting wheeled mobile robot for Mars explorationGajjar, Bhargav Ishwarlal 01 October 2002 (has links)
No description available.
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A geophysical study of the earth's crust in central Virginia with implications for lower crustal reflections and Appalachian crustal structurePratt, Thomas L. January 1986 (has links)
Reprocessing of the United States Geological Survey's seismic reflection profile along Interstate 64 (I64) across Virginia with a data extension to 14-sec two-way travel time has provided a stacked section suitable for an integrated interpretation of refraction, earthquake, and blast analyses done by previous workers as well as gravity modelling done in this study. The seismic reflection profile shows a highly reflective upper crust which is consistent with an allochthonous Blue Ridge Province, possibly with underlying thrust sheets, and a basal decollement at about 9 km (3 sec) depth. Immediately east of the Blue Ridge province, the Appalachian structures plunge to up to 12 km (4 sec) depth where their interpretation on the section becomes ambiguous. The Evington Group, Hardware Terrane, and Chopawamsic metavolcanic rocks exposed in the Piedmont Province correspond to numerous reflections which appear to overlie a shallowly (10° to 15°) west-dipping, highly reflective zone dipping from 1.5 sec beneath the Goochland Terrane to 5 sec beneath the Evington Group rocks. Some of the overlying reflections apparently root in this zone which is therefore interpreted to include decollement surfaces along which the overlying rocks were transported. Grenville basement rocks are interpreted to underlie this zone and form autochthonous basement beneath the entire western portion of the profile because relatively few reflections originate from within this region. The Goochland granulite terrane is interpreted as a nappe structure which has overridden a portion of the Chopawamsic metavolcanic rocks. The Goochland terrane is bounded on the east' on the section by a broad zone of east-dipping (20° to 45°) reflections which may penetrate to Moho depths and are possibly correlative with similar events seen on other Appalachian lines.
The 164 section contains a layered sequence of reflections at about 9 to 12 sec extending about 70 km west from Richmond, Virginia whose base coincides almost exactly with the Mohorovicic Discontinuity (Moho) interpreted from earlier refraction work. The deep reflections are thus believed to be lower crustal layering forming a 5 to 10 km thick Moho transition zone which is believed to persist across the state. The density contrast of 0.25 gm/cm³ between the lower crust and upper mantle derived from gravity modelling, the seismic transition zone, and the presence of intrusive rocks of lower crust-upper mantle origin at the surface are consistent with partial melting and contamination of the lower crust with upper mantle material.
The refraction data and gravity modelling are consistent with a crust which thins from about 52 km beneath the Appalachian mountains to about 35 km beneath Richmond, Virginia, and rethickens by up to 10 km beneath the zone of east-dipping events east of Richmond. The pervasiveness of the zone of east-dipping events on other seismic reflection lines and the continuity of the adjacent Piedmont gravity high suggest that a similar crustal profile occurs along the length of the Appalachians. / Ph. D.
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Spectroscopic characterization of transiting exoplanets : A study of the possibility to detect atmospheres around exoplanets using SIMPLEWaldén, Pierre, Aronson, Erik January 2011 (has links)
This report describes simulations of observations with the near-infrared high-resolution spectrometer SIMPLE that is proposed to the ESO telescope E-ELT. We simulate M4 and G2 stars with transiting Earth-like planets and the goal is to distinguish spectral features originating from the atmosphere of the exoplanet. Noise levels of different magnitudes are added to the simulations and the minimal signal-to-noise required for detection of the atmosphere is estimated. Our conclusion is that detection of atmospheric features looks promising using this setup.
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Returbiljett till apornas planet : En studie om primär och sekundär adaptionKivimäki, Tomi January 2012 (has links)
The purpose of this essay is to study two film adaptations of the original Planet of the Apes novel and see what kind of relationship the two adaptations have with each other. The main question is if the secondary film adaptation is restricted by the primary and if the relationships between these two are as two separate adaptations or as a remake of an adaptation. What the results of the study show is that the secondary adaptation can not be seen as a remake even though it gets some of its inspiration from both the original story as well as the primary adaptation. The secondary adaptation is, however, restricted in what it can adapt due to the primary adaptation having the first pick, at least if the secondary adaptation wishes to be a whole new adaptation and not a remake of the primary. The study shows also that the fidelity in the secondary adaptation is not necessarily to either the original or the primary but to the knowledge the audience has about the Planet of the Apes universe which they have gathered from all of the important versions of the story. The essay also states that there is yet much to learn about the relationship between secondary and primary film adaptations which means that the field is still in need of exploration.
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Un nouveau regard sur la Structure interne et l'évolution des planètes géantes solaires et extrasolaires / A new vision on (Extrasolar) Giant Planets Internal Structure and EvolutionLeconte, Jérémy 05 October 2011 (has links)
La détection et la caractérisation d'exoplanètes apparaissent clairement comme des thèmes centraux de l'observation astronomique pour les années à venir. Les projets spatiaux ou au sol sont nombreux (HARPS, CoRoT, Kepler, JWST, SPHERE...), mais les études théoriques visant à l'analyse et à la compréhension des données recueillies et à venir sont nécessaires. Durant cette thèse j'ai étudié divers processus physiques affectant la structure interne et l'évolution des planètes géantes, aussi bien au sein, qu'à l'extérieur de notre système solaire. J'ai notamment modélisé en détail: -L'impact de l'irradiation intense émise par l'étoile sur l'atmosphère d'une planète à faible distance orbitale, et l'effet induit sur l'évolution interne de cette planète. -Le couplage par dissipation de marée de l'évolution orbitale et thermique d'une planète interagissant avec sa proche étoile parente. -L'effet de la déformation due aux marées sur les paramètres observables d'une planète en transit grâce au suivi photométrique de son passage devant l'étoile. -L'incidence sur la structure et l'évolution d'une diminution de l'efficacité du transport de chaleur par convection due à un gradient d'éléments lourd dans l'enveloppe gazeuse d'une planète géante, conduisant au phénomène de convection double-diffusive. A travers l'étude des ces divers processus, j'ai développé différents modèles analytiques et codes numériques qui sont à la fois flexibles et robustes, et qui permettent maintenant d'étudier certaines propriétés des nouveaux objets substellaires détectés à mesure qu'ils sont découverts. / The detection and characterization of extrasolar planets clearly appears as one of the main goals of observational astronomy for the coming years. Space and ground project are numerous, but theoretical studies aimed at analyzing and understanding available and future data are needed. During this thesis, I study various physical processes affecting the internal structure and evolution of both solar, and extrasolar giant planets. In particular I investigate : -the impact of the intense stellar irradiation received by a close in planet on its subsequent internal evolution. This allows me to quantify the radius anomaly of bloated Hot Jupiters and to constrain their internal composition. -the tidal and centrifugal distortion of a fluid planet. By using both analytical and numerical models, I show how non-sphericity of the planet affects transit measurements, yielding an underestimation of its radius. -how the presence of double-diffusive convection caused by a heavy elements gradient in the gaseous envelope of a planet can decrease the efficiency of its internal heat transport, and affect its structure and evolution. -the coupling between the orbital and the thermal evolution of a planet arising from the strong star-planet tidal interaction. Subsequently, I find that tidal heating alone is not a viable explanation for the observed radius anomaly of transiting planets. Through these different studies, I developed various analytical models and numerical codes that are both flexible and robust, and which now allow one to study the properties of new extrasolar planets and brown dwarfs as they are discovered.
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The formation of Earth’s early felsic continental crust by water-present eclogite meltingLaurie, Angelique 03 1900 (has links)
Thesis (PhD)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: The sodic and leucocratic Tonalite, Trondhjemite and Granodiorite (TTG) granitoid series of
rocks characterise Paleo- to Meso- Archaean felsic continental crust, yet are uncommon in the
post-Archaean rock record. Consequently, petrogenetic studies on these rocks provide
valuable insight into the creation and evolution of Earth’s early continental crust. The highpressure
(HP)-type of Archaean TTG magmas are particularly important in this regard as their
geochemistry requires that they are formed by high-pressure melting of a garnet-rich eclogitic
source. This has been interpreted as evidence for the formation of these magmas by anatexis
of the upper portions of slabs within Archaean subduction zones. In general, TTG magmas
have been assumed to arise through fluid-absent partial melting of metamafic source rocks.
Therefore, very little experimental data on fluid-present eclogite melting to produce Archaean
TTG exist, despite the fact that water drives magmatism in modern arcs. Consequently, this
study experimentally investigates the role of fluid-present partial melting of eclogite-facies
metabasaltic rock in the production of Paleo- to Meso-Archaean HP-type TTG melts.
Experiments are conducted between 1.6 GPa and 3.0 GPa and 700 ºC and 900 ºC using
natural and synthetic eclogite, and gel starting materials of low-K2O basaltic composition.
Partial melting of the natural and synthetic eclogite occurred between 850 ºC and 870 ºC at
pressures above 1.8 GPa, and the melting reaction is characterised by the breakdown of sodic
clinopyroxene, quartz and water: Qtz + Cpx1 + H2O ± Grt1 = Melt + Cpx2 ± Grt2. The
experimental melts have the compositions of sodic peraluminous trondhjemites and have
compositions that are similar to the major, trace and rare earth element composition of HPtype
Archaean TTG. This study suggests that fluid-present eclogite melting is a viable petrogenetic model for this component of Paleo- to Meso-Archaean TTG crust. The nature of
the wet low-K2O eclogite-facies metamafic rock solidus has been experimentally defined and
inflects towards higher temperatures at the position of the plagioclase-out reaction. Therefore,
the results indicate that a crystalline starting material is necessary to define this solidus to
avoid metastable melting beyond temperatures of the Pl + H2O + Qtz solidus at pressures
above plagioclase stability. Furthermore, this study uses numerical and metamorphic models
to demonstrate that for reasonable Archaean mantle wedge temperatures within a potential
Archaean subduction zone, the bulk of the water produced by metamorphic reactions within
the slabs is captured by an anatectic zone near the slab surface. Therefore, this geodynamic
model may account for HP-type Archaean TTG production and additionally provides
constraints for likely Archaean subduction. The shape of the relevant fluid-present solidus is
similar to the shape of the pressure-temperature paths followed by upper levels of the
proposed Archaean subducting slab, which makes water-fluxed slab anatexis is very
dependant on the temperature in the mantle wedge. I propose that cooling of the upper mantle
by only a small amount during the late Archaean ended fluid-present melting of the slab. This
allowed slab water to migrate into the wedge and produce intermediate composition
magmatism which has since been associated with subduction zones. / AFRIKAANSE OPSOMMING: Die reeks natruimhoudende en leukokraties Tonaliet, Trondhjemiet en Granodioriet (TTG)
felsiese stollingsgesteentes is kenmerkend in die Paleo- tot Meso-Argeïkum felsiese
kontinentale kors, maar is ongewoon in die post-Argeïese rots rekord. Gevolglik,
petrogenetiese studies op hierdie rotse verskaf waardevolle insig in die skepping en evolusie
van die aarde se vroeë kontinentale kors. Die hoë-druk (HD)-tipe van die Argeïkum TTG
magmas is veral belangrik in hierdie verband as hulle geochemie vereis dat hulle gevorm
word deur hoë druk smelting van 'n granaat-ryk eklogitiese bron. Dit word interpreteer as
bewys vir die vorming van hierdie magmas deur smelting van die boonste gedeeltes van die
blaaie in Argeïese subduksie sones. TTG magmas in die algemeen, is veronderstel om op te
staan deur middel van water-afwesig gedeeltelike smelting van metamafiese bron rotse.
Daarom bestaan baie min eksperimentele data op water-teenwoordig eklogiet smelting om
Argeïkum TTG te produseer, ten spyte van die feit dat water magmatisme dryf in moderne
boë. Gevolglik is hierdie studie ‘n eksperimentele ondersoek in die rol van water-teenwoordig
gedeeltelike smelting van eklogiet-fasies metamafiese rots in die produksie van Paleo- tot
Meso-Argeïkum HD-tipe TTG smelte. Eksperimente word uitgevoer tussen 1.6 GPa en 3.0
GPa en 700 ºC en 900 ºC met behulp van natuurlike en sintetiese eklogiet, en gel begin
materiaal van lae-K2O basaltiese samestelling. Gedeeltelike smelting van die natuurlike en
sintetiese eklogiet het plaasgevind tussen 850 ºC en 870 ºC te druk bo 1.8 GPa, en die
smeltings reaksie is gekenmerk deur die afbreek van natruimhoudende klinopirokseen, kwarts
en water: Qtz + Cpx1 + H2O ± Grt1 = Smelt + Cpx2 ± Grt2. Die eksperimentele smelte het die
komposisies van natruimhoudende trondhjemites en is soortgelyk aan die hoof-, spoor- en seldsame aard element samestelling van HD-tipe Argeïkum TTG. Hierdie studie dui daarop
dat water-teenwoordig eklogiet smelting 'n lewensvatbare petrogenetiese model is vir hierdie
komponent van Paleo- tot Meso-Argeïkum TTG kors. Die aard van die nat lae-K2O eklogietfasies
metamafiese rock solidus is eksperimenteel gedefinieër en beweeg na hoër temperature
by die posisie van die plagioklaas-out reaksie. Daarom dui die resultate daarop dat 'n
kristallyne materiaal nodig is om hierdie solidus te definieër en metastabiele smelting buite
temperature van die Pl + H2O + Qtz solidus druk bo plagioklaas stabiliteit te vermy. Verder
maak hierdie studie gebruik van numeriese en metamorfiese modelle om aan te dui dat die
grootste deel van die water geproduseer deur metamorfiese reaksies binne die blaaie bestaan
vir redelike Argeïkum mantel wig temperature binne 'n potensiële Argeïkum subduksie sone,
en word opgevang deur 'n smelting sone naby die blad oppervlak. Daarom kan hierdie
geodinamies model rekenskap gee vir HD-tipe Argeïkum TTG produksie en dit bied ook die
beperkinge vir waarskynlik Argeïese subduksie. Die vorm van die betrokke waterteenwoordig
solidus is soortgelyk aan die vorm van die druk-temperatuur paaie gevolg deur
die boonste vlakke van die voorgestelde Argeïkum subderende blad, wat water-vloeiing blad
smeltingbaie afhanklik maak van die temperatuur in die mantel wig. Ons stel voor dat
afkoeling van die boonste mantel met slegs 'n klein hoeveelheid gedurende die laat Argeïese,
die water-vloeiing smelting van die blad beëindig. Dit het toegelaat dat die blad water in die
wig migreer en intermediêre samestelling magmatisme produseer wat sedert geassosieer
word met subduksie sones.
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Exoplanets in Open Clusters and Binaries: New Constraints on Planetary MigrationQuinn, Samuel N 12 August 2016 (has links)
In this dissertation, we present three complementary studies of the processes that drive planetary migration. The first is a radial-velocity survey in search of giant planets in adolescent (<1 >Gyr) open clusters. While several different mechanisms may act to drive giant planets inward, only some mechanisms will excite high eccentricities while doing so. Measuring the eccentricities of young hot Jupiters in these clusters (at a time before the orbits have had a chance to circularize due to tidal friction with their host stars) will allow us to identify which mechanisms are most important. Through this survey, we detect the first 3 hot Jupiters in open clusters (and at least 4 long-period planets), and we measure the occurrence rate of hot Jupiters in clusters to be similar to that of the field (~1%). We determine via analyses of hot Jupiter eccentricities and outer companions in these systems that high eccentricity migration mechanisms (those requiring the presence of a third body) are important for migration. The second project, an adaptive optics imaging survey for stellar companions to known hot Jupiter hosts, aims to determine the role that stellar companions in particular play in giant planet migration. Through a preliminary analysis, we derive a lower limit on the binary frequency of 45% (greater than that of the typical field star), and we find that the presence of a companion is correlated with misalignment of the spin-orbit angle of the planetary system, as would be expected for stellar Kozai-Lidov migration: at least 74% of misaligned systems reside in binaries. We thus conclude that among high eccentricity migration mechanisms, those requiring a stellar companion play a significant role. Finally, we describe simulations of measurements of the planet population expected to be discovered by TESS, and use these to demonstrate that a strong constraint on the obliquity distribution of small planets can be derived using only TESS photometry, Gaia astrometry, and vsin(i) measurements of the host stars. This obliquity distribution will be a key piece of evidence to help detemine the likely formation and migration histories of small planets, and can contribute to the assessment of the potential for Earth-like planets to harbor life.
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Analytical and numerical studies of several fluid mechanical problemsKong, Dali January 2012 (has links)
In this thesis, three parts, each with several chapters, are respectively devoted to hydrostatic, viscous and inertial fluids theories and applications. In the hydrostatics part, the classical Maclaurin spheroids theory is generalized, for the first time, to a more realistic multi-layer model, which enables the studies of some gravity problems and direct numerical simulations of flows in fast rotating spheroidal cavities. As an application of the figure theory, the zonal flow in the deep atmosphere of Jupiter is investigated for a better understanding of the Jovian gravity field. High viscosity flows, for example Stokes flows, occur in a lot of processes involving low-speed motions in fluids. Microorganism swimming is such typical a case. A fully three dimensional analytic solution of incompressible Stokes equation is derived in the exterior domain of an arbitrarily translating and rotating prolate spheroid, which models a large family of microorganisms such as cocci bacteria. The solution is then applied to the magnetotactic bacteria swimming problem and good consistency has been found between theoretical predictions and laboratory observations of the moving patterns of such bacteria under magnetic fields. In the analysis of dynamics of planetary fluid systems, which are featured by fast rotation and very small viscosity effects, three dimensional fully nonlinear numerical simulations of Navier-Stokes equations play important roles. A precession driven flow in a rotating channel is studied by the combination of asymptotic analyses and fully numerical simulations. Various results of laminar and turbulent flows are thereby presented. Computational fluid dynamics requires massive computing capability. To make full use of the power of modern high performance computing facilities, a C++ finite-element analysis code is under development based on PETSc platform. The code and data structures will be elaborated, along with the presentations of some preliminary results.
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