Charging of dust grains in ionized media

Katedra fyziky povrchů a plazmatuDepartment of Surface and Plasma ScienceFaculty of Mathematics and PhysicsMatematicko-fyzikální fakult

Loops of Interactions

Text pojednává o problematice interaktivních uměleckých děl, ve kterých tvůrci chtějí, aby významy, které si recipienti odnáší, vznikaly právě skrz interaktivitu. Pomocí rozboru uměleckých děl z různých médií (literatura, videohry, stolní vyprávěcí hry a malba) a s využitím teorie herního designu autor popisuje, jak může vznikat význam pomocí interaktivity a kde mohou vzniknout překážky při snaze o významotvornou interaktivitu. Dále autor přibližuje, jak mohou tvůrci nepřímo kontrolovat chování recipientů v rámci interaktivity, aniž by narušili pocit jejich svobody, a jak mohou být akce a reakce recipientů součástí dramaturgie. Na základě tohoto všeho se pak autor snaží definovat obecné dramaturgické principy, které by mohly pomoct tvůrcům k preciznější dramaturgii interaktivních děl

Dust observations with antenna measurements and its prospects for observations with Parker Solar Probe and Solar Orbiter

The electric and magnetic field instrument suite FIELDS on board the NASA Parker Solar Probe and the radio and plasma waves instrument RPW on the ESA Solar Orbiter mission that explore the inner heliosphere are sensitive to signals generated by dust impacts. Dust impacts have been observed using electric field antennas on spacecraft since the 1980s and the method was recently used with a number of space missions to derive dust fluxes. Here, we consider the details of dust impacts, subsequent development of the impact generated plasma and how it produces the measured signals. We describe empirical approaches to characterise the signals and compare these in a qualitative discussion of laboratory simulations to predict signal shapes for spacecraft measurements in the inner solar system. While the amount of charge production from a dust impact will be higher near the Sun than observed in the interplanetary medium before, the amplitude of pulses is determined by the recovery behaviour that is different near the Sun since it varies with the plasma environment

The Comet Interceptor Mission

Here we describe the novel, multi-point Comet Interceptor mission. It is dedicated to the exploration of a little-processed long-period comet, possibly entering the inner Solar System for the first time, or to encounter an interstellar object originating at another star. The objectives of the mission are to address the following questions: What are the surface composition, shape, morphology, and structure of the target object? What is the composition of the gas and dust in the coma, its connection to the nucleus, and the nature of its interaction with the solar wind? The mission was proposed to the European Space Agency in 2018, and formally adopted by the agency in June 2022, for launch in 2029 together with the Ariel mission. Comet Interceptor will take advantage of the opportunity presented by ESA's F-Class call for fast, flexible, low-cost missions to which it was proposed. The call required a launch to a halo orbit around the Sun-Earth L2 point. The mission can take advantage of this placement to wait for the discovery of a suitable comet reachable with its minimum ΔV capability of 600 ms-1. Comet Interceptor will be unique in encountering and studying, at a nominal closest approach distance of 1000 km, a comet that represents a near-pristine sample of material from the formation of the Solar System. It will also add a capability that no previous cometary mission has had, which is to deploy two sub-probes - B1, provided by the Japanese space agency, JAXA, and B2 - that will follow different trajectories through the coma. While the main probe passes at a nominal 1000 km distance, probes B1 and B2 will follow different chords through the coma at distances of 850 km and 400 km, respectively. The result will be unique, simultaneous, spatially resolved information of the 3-dimensional properties of the target comet and its interaction with the space environment. We present the mission's science background leading to these objectives, as well as an overview of the scientific instruments, mission design, and schedule

Moonraker — Enceladus Multiple Flyby Mission

Enceladus, an icy moon of Saturn, possesses an internal water ocean and jets expelling ocean material into space. Cassini investigations indicated that the subsurface ocean could be a habitable environment having a complex interaction with the rocky core. Further investigation of the composition of the plume formed by the jets is necessary to fully understand the ocean, its potential habitability, and what it tells us about Enceladus's origin. Moonraker has been proposed as an ESA M-class mission designed to orbit Saturn and perform multiple flybys of Enceladus, focusing on traversals of the plume. The proposed Moonraker mission consists of an ESA-provided platform with strong heritage from JUICE and Mars Sample Return and carrying a suite of instruments dedicated to plume and surface analysis. The nominal Moonraker mission has a duration of ∼13.5 yr. It includes a 23-flyby segment with 189 days allocated for the science phase and can be expanded with additional segments if resources allow. The mission concept consists of investigating (i) the habitability conditions of present-day Enceladus and its internal ocean, (ii) the mechanisms at play for the communication between the internal ocean and the surface of the South Polar Terrain, and (iii) the formation conditions of the moon. Moonraker, thanks to state-of-the-art instruments representing a significant improvement over Cassini's payload, would quantify the abundance of key species in the plume, isotopic ratios, and the physical parameters of the plume and the surface. Such a mission would pave the way for a possible future landed mission

The Comet Interceptor Mission

Here we describe the novel, multi-point Comet Interceptor mission. It is dedicated to the exploration of a little-processed long-period comet, possibly entering the inner Solar System for the first time, or to encounter an interstellar object originating at another star. The objectives of the mission are to address the following questions: What are the surface composition, shape, morphology, and structure of the target object? What is the composition of the gas and dust in the coma, its connection to the nucleus, and the nature of its interaction with the solar wind? The mission was proposed to the European Space Agency in 2018, and formally adopted by the agency in June 2022, for launch in 2029 together with the Ariel mission. Comet Interceptor will take advantage of the opportunity presented by ESA’s F-Class call for fast, flexible, low-cost missions to which it was proposed. The call required a launch to a halo orbit around the Sun-Earth L2 point. The mission can take advantage of this placement to wait for the discovery of a suitable comet reachable with its minimum ΔV capability of 600 ms−1. Comet Interceptor will be unique in encountering and studying, at a nominal closest approach distance of 1000 km, a comet that represents a near-pristine sample of material from the formation of the Solar System. It will also add a capability that no previous cometary mission has had, which is to deploy two sub-probes – B1, provided by the Japanese space agency, JAXA, and B2 – that will follow different trajectories through the coma. While the main probe passes at a nominal 1000 km distance, probes B1 and B2 will follow different chords through the coma at distances of 850 km and 400 km, respectively. The result will be unique, simultaneous, spatially resolved information of the 3-dimensional properties of the target comet and its interaction with the space environment. We present the mission’s science background leading to these objectives, as well as an overview of the scientific instruments, mission design, and schedule

Charging of dust grains in ionized media

Katedra fyziky povrchů a plazmatuDepartment of Surface and Plasma ScienceFaculty of Mathematics and PhysicsMatematicko-fyzikální fakult

E-learning

This bachelor thesis describes new way of learning, which is used as an extension for the common learning and it is called e-learning. There is described evolution of this new way, it's participants, who manage to organize this type of learning. Also we can see in this thesis individual learning theories, which are cores for the new electronic materials. At the end of the theoretical part we have e-learning standards and principles. In the practical part are described most used electronic materials and also via multicriterial analysis we can see which one of them is best to use. At the end we have two conlusions, the first one is developer conlusion and the second one is user conlusion. Next we can see modern trends of learning and their prediction. At the end of the bachelor thesis is described proposal how to make and implement electronic material

Properties and application of ferrofluids

Ferokapaliny jsou látky, jejichž vlastnosti je možné měnit za pomoci vnějšího magnetického pole. V teoretické části této bakalářské práce je popsána jejich struktura, vlastnosti a možnosti výroby těchto kapalin. V další kapitole jsou uvedeny i praktické příklady využití ferokapalin a kam může směřovat aktuální výzkum. Hlavním cílem experimentální části je změření a vyhodnocení povrchového napětí dvou různých vzorků ferokapalin na bázi kerosinu.Ferrofluids are substances that can change their properties through an external magnetic field. The theoretical part of this bachelor thesis explains the nature and properties of these liquids, and how they are made. The next chapter provides concrete examples of ferrofluid use, and where it is possible to direct current research. The principal objective of the experimental part is to measure and evaluate the surface tension of two different samples of kerosene-based ferrofluids.

CFD simulation of the hydrokinetic energy converter using flow-induced vibrations

Vibrace indukované prouděním na tělesech o různých tvarech jsou zkoumány pomocí CFD simulací. Zjišťován je vliv hmotnosti tělesa, tuhosti pružiny a hodnoty přidaného tlumení na dynamické chování soustavy. K rozpohybování tělesa v proudu kapaliny je využita funkce 6DOF v kombinaci s dynamickou výpočetní sítí. Výstupem je vyhodnocení působících sil na těleso, dráha pohybu a případný výkon, který by těleso svým pohybem mohlo vygenerovat.Flow-induced vibrations on bodies of different shapes are investigated by CFD simulations. The influence of the mass of the body, the spring stiffness and the value of the added damping on the dynamic behaviour of the system is evaluated. A combination of the 6DOF function and a dynamic computational mesh is used to move the body around the y-axis solely by fluid flow. The output is an evaluation of the forces acting on the body, the trajectory of the body and the possible power that the body could generate by its motion.