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.
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Showing 1 to 20 of 27 for “"Line profiles"”.
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Modelling the balmer line profiles in the spectra of symbiotic stars
The Balmer emission lines in the spectra of symbiotic stars are often seen to have a double-peaked morphology when observed at high resolution. In this respect, they bear striking similarities to the Balmer line profiles in the spectra of cataclysmic variables, (Cv's) where their origin is ascribed …
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Excitation processes in the positive column of electrical discharges in inert gases
… current i, of the intensity, I, of neon spectral lines emitted from low pressure positive column discharges has been studied as part of an investigation of excitation processes in these discharges. The results indicate that two-step excitation is important for many neon lines. Measurements of …
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The Inner Gaseous Disks Of Herbig Be Stars
… reasonable matches were found for all emission line profiles considered individually; however, for each star, no disk density model based on a single power law for the equatorial density was able to simultaneously fit all of the observed emission lines in the spectrum. For BD+65 1637, the …
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A simulation model for stress measurements in notched test specimens by x-ray diffraction
… of the stress state in the form of x-ray line profiles; this is useful in the understanding and measurement of effects due to such stress states obtained in actual experiments. The theoretical relationship between the stress gradient and the depth of penetration of the x-ray beam at the …
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High resolution spectroscopy of photospheric bright points
… of the speckle deconvolution on spectral line profiles. In this thesis, the results of such an analysis are presented, followed by a conclusion that speckle-reconstructed spectral line profiles can be used for quantitative spectroscopy. <br> <br> The data set presented in this thesis …
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Probing giant-planet forming zones around Solar-like stars with CO
… of constraining turbulent velocities with CO line profiles in Chapter 4. Peak-to-trough ratios of CO rotational lines have been proposed as a robust probe for turbulent velocity. However we show that the peak-to-trough ratio could vary by $25\%$ due uncertainties in effects of CO depletion. …
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Ultrafast Dynamics and Nonlinear Interactions in Alkali Atoms and Diatomics
… dimer and to study atomic wavepackets and nonlinear effects in Rubidium and Potassium. Two color, pump-probe techniques have been used to probe the time evolution of wavepackets in the B, C, and D rovibrational levels of Cs$\sb2$. The temporal history of the wavepacket is inferred from the …
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Lyα emission as a sensitive probe of galactic mergers and reionization
… scattering produces extended red wings in the line profiles, which enhance transmission through the neutral intergalactic medium (IGM). Our simulations successfully reproduce several JWST observations with the assumption of minimal interstellar dust content. • How can we interpret the detection …
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Displacement of Fluid Droplets From Solid Surfaces
… In earlier studies, the treatment of the contact line has been simplified by assuming fixed geometrical shapes such as circles or ellipses. In our study, we model the true physics by solving for the actual contour of the contact line as determined by the contact angle hysteresis thetaA -- thetaR. …
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The impact of environment on the evolution of protoplanetary discs
… can be probed by spatially resolved $^{12}$CO line profiles. The two most relevant environmental mechanisms affecting protoplanetary discs are star-disc encounters, and external photoevaporation. In this thesis, I show that sub-mm observations of the RW Aur system are well described by an …
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The Importance of Photoevaporation in the Evolution of Protoplanetary Discs
… in observations of atomic forbidden emission lines and so how both line profiles and spatially resolved emission may be used to constrain the wind's nature; c) by including photoevaporation in models of disc evolution on secular timescales that predict its interplay with other processes - and …
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An analysis of beta cephei stars in NGC 3293 and the effects of stellar rotation
… parameters as well. Thermally broadened spectral line profiles are calculated for the same model, for modes with l = 0 to 4 and equatorial rotation velocities up to 400 km/s. Neglect of rotational distortion is shown to lead to underestimation of true equatorial rotation velocities by as much as …
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Error Estimations in the Design of a Terrain Measurement System
… surfaces, most of them historically single line profiles, with more modern equipment capable of capturing three dimensional measurements of the terrain surface. �These more modern systems are often constructed using a combination of various sensors which allow the system to measure the …
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Spectroscopic Measurements of Magnetic Field and Electron Density on Wire Array and Laser Plasmas
… limitations when plasma conditions are such that line broadening due to the high plasma density and temperature surpasses the Zeeman splitting. The Zeeman broadening technique provides a solution to this field measurement problem by making simultaneous measurements of the widths of multiplet …
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DNA microarray image processing based on advanced pattern recognition techniques
… wavelet transform (CWT) was performed. Line profiles of x and y axis were calculated, resulting to 2 different signals. These signals were independently processed by means of CWT at 15 different levels, using daubechies 4 mother wavelet. A summation, point by point, was performed on the …
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A multi-molecular line study of an entire giant molecular cloud
… here are the results of multi-molecular lines mapping of the entire giant molecular cloud G333, comprised sites of low- and high-mass star forming regions in various evolution stages of star formation. The result shows the spatial distribution of CS, HCO+, HCN and HNC are similar on large …
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The Lunar Exosphere: Spatial and Temporal Variations of Sodium and Potassium Emissions from November 2013 to May 2014
… by measuring sodium and potassium spectral line profiles to determine spatial and temporal variations in exospheric effective temperatures and velocities. Observations were made from the National Solar Observatory (MMP) at Kitt Peak, Arizona from November 2013 to May 2014, with the exception …
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Bright Z ~ 3 Lyman Break Galaxies in Deep Wide Field Surveys
… broader Lyα emission and ISM absorption line profiles, and more prominent CIV P-Cygni profile. This profile may imply a top-heavy IMF in these ULBGs. The ULBGs have larger stellar mass and SFR, but smaller dust extinction than the typical L* LBGs at z ~ 2 - 3. We proposed two evolutionary …
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Simulation studies on X-ray imaging of brain parenchyma and tumors
… were used and it was decided to use a non-linear decomposition dual energy technique for blending the images from different energies. The DE algorithm truly managed to produce contrast between brain parenchyma tissues in all a cases used even in real data. Due to the great number of images …
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A multi-frequency study of symbiotic stars
… the maximum possible range of diagnostic tools - line ratios, profiles and intensities and continuum flux densities. This then is the general theme of the work presented in this thesis. The results of a low dispersion, optical spectroscopic survey of northern sky symbiotics are presented and …
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