Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 94 for “"Pulsation"”.
-
Hot subluminous stars: Time-series analysis and pulsation mode identification
Contains fulltext : 322902.pdf (Publisher’s version ) (Open Access)
-
Peripher induzierte Pulsation eines fovealen Nachbildes: Nachweis eines weitreichenden neuronalen Effektes
… durch meine Versuche aus, dass die Nachbildpulsation allein durch einen lokalen Einfluss, wie Pupillenänderung, Simultankontrast oder Streulicht verursacht ist. Daraus folgere ich, dass die beobachtete Nachbildpulsation auf einem weitreichenden, neuronalen Signal aus dem Umfeld beruht. …
-
Amplitude modulation and energy conservation of pulsation modes in delta Scuti stars
The pulsations in δ Sct stars are excited by a heat engine driving mechanism caused by in-creased opacity in their surface layers, and have pulsation periods of order a few hours. Space based observations in the last decade have revealed a diverse range of pulsational be-haviour in these stars, …
-
Investigation of velocity gradient as driving force of flow pulsation in fuel assemblies
The presence of quasi-periodic flow pulsations in fuel assemblies has been observed since the 1960's but is still not fully understood. Current design and licensing practices for nuclear reactor fuel mostly rely on 1-dimensional subchannel simulation tools, which might not accurately predict the …
-
A combined modeling and experimental study assessing the impact of fluid pulsation and operating schemes on charge and energy efficiency in capacitive deionization
Cell-cycling performance in capacitive deionization (CDI) can suffer from various charge-efficiency loss mechanisms. In conventional CDI, we show that salt residue within electrodes introduces a temporal lag between charge and desalination stages of a CDI cycle. Without accounting for this effect …
-
Local instantaneous convective heat transfer characteristics from mechanical and supply pulsed radial reattaching nozzles
… flow guide height (0.8 and 1.16), mechanical pulsation rate (5 and 10 Hz), supply pulsation rate (10, 20, 30, and 40 Hz), phase angle (0° and 180°), and Reynolds number (1683 and 2366). Air was forced through a supply pulsation mechanism and then through a pulsated nozzle diverter apparatus. …
-
Studies of non-adiabatic pulsations in the atmospheres of the roAp stars
… photometry of roAp stars shows that their pulsation amplitudes decrease more rapidly with increasing wavelength compared to other classically pulsating stars (e.g. Medupe & Kurtz 1998). In addition, this thesis shows that the pulsation phase can vary by up to 80° from Johnson U to V …
-
An analysis of beta cephei stars in NGC 3293 and the effects of stellar rotation
… the identification of many formerly unknown pulsation frequencies in these stars, by means of Fourier periodogram analysis. All of the stars are found to be multiperiodic, with up to five frequencies identified for individual stars. Physical parameters of the stars are determined from …
-
Dynamic response of small turbine flowmeters in pulsating liquid flows
… for predicted values of the amplitude of the pulsations (amplitude attenuation). This behaviour is due to the fundamental asymmetry between flows with increasing and decreasing angle of attack relative to the meter blades, throughout a pulsation cycle. This qualitative behaviour was confirmed …
-
LES of pulsatile flow in the models of arterial stenosis and aneurysm
… obtained by the additive and non-additive pulsation. Secondly, the physiological pulsatile flow in the same model stenosis is investigated, where the physiological pulsation is generated at the inlet using the first four harmonics of the Fourier series of pressure pulse. A comparison …
-
Transition to turbulence and relaminarization of pulsatile pipe flows
… to set up a water flow system and provide the pulsation characteristics. Time-resolved particle image velocimetry data were acquired in a refractive index matching setup by using a continuous wave laser and a high-frame-rate digital camera. The position of the piston was continuously recorded …
-
Characterisation Of The Blazhko Effect In RR Lyrae Stars Using SuperWASP Data
… structure and evolution models. The stellar pulsation mechanism and modulation are introduced before comparing the WASP project to other wide-field surveys. The aim of this research is to identify correlations between the basic pulsation and Blazhko effect characteristics that may provide …
-
Heat transfer enhancement phenomena and pressure drop characteristics in two-phase pulsating flow using R-134A
… saturation temperature 15 oC (59 oF); flow pulsation period (2-24 sec). The temporal pressure drop data was recorded and used as the basis of a newly proposed close-form model for predicting the heat transfer and pressure drop for pulsating two-phase flow based on the quasi-steady state …
-
Pulsations in the white dwarf primary of a cataclysmic variable star
… GW Librae during 1997 and 1998. The power in the pulsation spectrum concentrates principally in regions near 376s and 650s. GW Librae has a pulsation spectrum that shows dramatic changes on a monthly basis, typical of the pulsating DA white dwarfs.
-
Reentrainment of Submicron Solid Particles
… study the effects of particle size, flow rate, pulsation, particle/substrate material, and temperature on the short-term reentrainment of submicron particles. The particles tested are in the size range of 10-900 nm and are deposited by wetting the inside of capillary tubes with a liquid …
-
Investigating the A-type stars using Kepler data
… targets for detailed investigation with Kepler. Pulsation is a common phenomenon in A stars. The δ Sct stars receive wide attention but the fraction of stars that pulsate at the 50 μmag level is shown to be only 56 per cent. The non-δ Sct stars in the δ Sct instability strip receive far less …
-
A study of unstable axisymmetric separation in high speed flows
… flow were observed namely, oscillation and pulsation. Both modes showed the non-dimensional frequency to decrease as t/D was i~creased independent of Φ<sub>D</sub>, Re<sub>D</sub>, and M. The amplitude, Δp was found to be a strong function of l/D, Φ<sub>D</sub> , Re<sub>D</sub> and M. …
-
A spectroscopic study of the rapidly oscillating peculiar A star HD 134214
… spectroscopic observations did discover a 21 mm pulsation in HD 116114 and as a result further investigations were confined to spectroscopy. In addition a theoretical model of the atmosphere of an roAp star was developed involving a standing wave with a running wave component. This model appears …
Page 1 of 5