Sökning: "fysik v"

Visar resultat 1 - 5 av 137 uppsatser innehållade orden fysik v.

  1. 1. Gravitational Collapse of a Massless Scalar Field in a Theory of Minimally Modified Gravity

    Master-uppsats, KTH/Fysik

    Författare :Atabak Fathe Jalali; [2024]
    Nyckelord :Theoretical physics; astrophysics; modified gravity; minimally modified gravity; gravitational collapse; VCDM; scalar collapse; apparent horizon; numerical relativity; Teoretisk fysik; astrofysik; modifierad gravitation; minimalt modifierad gravitation; gravitationskollaps; VCDM; skalär kollaps; uppenbar horisont; numerisk relativitet;

    Sammanfattning : This thesis explores the spherically symmetric gravitational collapse of a massless scalar field in a minimally modified gravity theory denoted VCDM (V replaces $\Lambda$ in the $\Lambda$CDM abbreviation), a class of theories propagating the same degrees of freedom as general relativity at the expense of broken 4D diffeomorphism invariance. Numerical evolution of the equations of motion reveals that for small initial scalar profile amplitudes, no black hole forms from the collapse. LÄS MER

  3. 2. Juice/JDC ion measurement perturbations caused by spacecraft charging in the solar wind and Earth’s magnetosheath

    Master-uppsats, Uppsala universitet/Institutionen för fysik och astronomi

    Författare :Derek van Winden; [2024]
    Nyckelord :Juice; Jupiter Icy Moons Explorer; JDC; Jovian plasma Dynamics and Composition analyzer; Particle Environment Package; PEP; Jupiter; Ganymede; Callisto; Europa; solar wind; magnetosheath; spacecraft charging; Spacecraft Plasma Interaction Software; SPIS; charging; plasma; measurement perturbations; perturbation; distortion; particle detector; Institutet för Rymdfysik; IRF; Dublin Institute for Advanced Studies; DIAS; European Space Agency; ESA;

    Sammanfattning :  In July 2031, a new chapter in the exploration of the Jovian system will begin with the arrival of the Jupiter Icy Moons Explorer (Juice) at Jupiter. Launched on April 14 2024 as part of ESA’s Cosmic Vision programme, the mission aims to study Jupiter and its icy Galilean moons Callisto, Europa, and Ganymede. LÄS MER

  4. 3. Fitting a photospheric prompt emission model to GRB data: The Kompaneets RMS approximation (KRA)

    Master-uppsats, KTH/Fysik

    Författare :Oscar Wistemar; [2023]
    Nyckelord :Gamma-Ray Bursts; Astrophysics; Engineering Physics; Gamma-Blixtar; Astrofysik; Teknisk Fysik;

    Sammanfattning : Gamma-ray bursts (GRBs) are some of the most energetic events in the universe. Shocks occurring below the photosphere are likely radiation mediated shocks (RMSs) and are suspected to shape the spectra. Due to computational costs of simulating RMSs, models had not been fitted to data and a faster model was needed. LÄS MER

  5. 4. Superconducting gates for InP HEMTs

    Master-uppsats, KTH/Tillämpad fysik

    Författare :Sebastian Alveteg; [2023]
    Nyckelord :Cryogenic electronics; HEMT; Superconductors; Applied Physics; Kryogenisk elektronik; HEMT; Supraledare; Tillämpad fysik;

    Sammanfattning : The thesis examines the prospects of using the superconductor NbN as the gatemetal for an InP HEMT. A HEMT or High Electron Mobility Transistor is aheterostructure transistor engineered to reach very high electron mobility. InPHEMTs are used as cryogenic Low Noise Amplifiers (LNAs), which have increasedin demand as quantum computing is scaling up. LÄS MER

  7. 5. Design av en hydraulisk bandspännare

    Uppsats för yrkesexamina på grundnivå, Umeå universitet/Institutionen för tillämpad fysik och elektronik

    Författare :Nils Forsman; [2023]
    Nyckelord :skogsmaskinsband; skogsmaskin; hydraulik;

    Sammanfattning : Olofsfors AB tillverkar bland annat boggiband för skogsmaskiner. Dessa band kräver en extern spännare vid montering som i dagsläget finns i manuellt och skruvdragardrivet utförande. LÄS MER