No description available.

The purpose of this study is to investigate the rate of natural fermentation of solutions at different temperatures. Whatever microorganisms that chanced to be present in the air and that chanced to fall into the inoculating medium are the ones which brought about fermentation when transferred to the fermentable solution.

Non-migrating tides are understood to be an important coupling mechanism through which lower atmospheric conditions influence the variability of the near-Earth space environment. Tidal variations have been exhaustively characterized in the mesosphere/lower thermosphere and the upper thermosphere, yet it is not quite known to what extent tides appear in the middle thermosphere due to a lack of global-scale systematic observations. This dissertation addresses the middle thermospheric "gap" of tidal observations. Using far ultraviolet (FUV) observations of the Earth, the recent NASA GOLD and ICON missions retrieve thermospheric parameters, the former from geostationary orbit (GEO) and the latter from low Earth orbit. Both missions infer the daytime column O/N2 ratio, while GOLD also retrieves the daytime thermospheric disk temperature. Traditional spectral tidal decomposition cannot be employed on GOLD data due its incomplete longitude/local solar time sampling. The known limitation introduced by ionospheric contamination of emissions at 135.6 nm and the dependence of the GOLD disk temperature on solar zenith angle both serve as additional obstacles. This dissertation proposes a pair of algorithms, based on the local time sum and difference approaches, that retrieves diurnal and semidiurnal tidal parameters for temperature and O/N2 in a single inversion, while constraining the tidal phase differences in temperature and O/N2 using a general circulation model. The first estimates of non-migrating tidal amplitudes and phases in middle thermospheric temperature and O/N2 using a geostationary observational platform are presented. Comparisons to physics-based and empirical models reveal that modeled amplitudes are generally weaker than the amplitudes retrieved from GOLD data, highlighting the need for better representation of tidal dynamics. In addition, this dissertation proposes a universal approach to systematically reduce the ionospheric contamination of O/N2 and thus determine the true thermospheric tidal variations. The approach considers biases between the remote sensing and ionospheric data sets, and due to its universality can be adapted for any retrieval of O/N2 from far ultraviolet emissions. The modified O/N2 shows a wavenumber-3 pattern indicative of the diurnal eastward propagating zonal wavenumber 2 tide (DE2), where it was not present in the original O/N2. This DE2 presence as well as the finding of DE3 and SE2 signatures in wavenumber-4 patterns is consistent with the theory that upward propagating tides influence the longitudinal structure of the thermospheric composition. / Doctor of Philosophy / A remarkable amount of variability in the upper atmosphere is not explained by the state-of-the-art description of the connected Sun-Earth system. Understanding the mechanisms of said variability is instrumental to achieving operational space weather forecasting, a capability that would alleviate the uncertainties faced by space activities such as GPS. Solar atmospheric tides have been studied as a coupling mechanism between terrestrial weather and space weather, and thus believed to be responsible for much of the variability not accounted for. These tides are periodic planetary-scale oscillations of the atmosphere, principally forced by the heating of the atmosphere by solar radiation. A subset of them, called non-migrating tides, do not track the motion of the Sun across the sky. Non-migrating tides in the upper atmosphere are forced in a myriad of ways, including but not limited to large-scale tropical weather systems and the interactions of the migrating tide with other waves. They are known to redistribute the charged particles of the ionosphere, thus influencing radio communications. This dissertation presents novel methods to studying non-migrating tides in a region of the upper atmosphere, the middle thermosphere (around 150 km altitude), where observations of them are sparse. A pair of methods was devised to overcome the limited sampling of temperature and composition from geostationary orbit, where a satellite appears fixed to a ground-based observer. Another method addresses a limitation that has afflicted prior investigations of non-migrating tides in neutral composition based on far ultraviolet observations. These methods use data collected by the NASA GOLD and ICON missions, modern space-based Earth observation missions that make crucial measurements of the middle thermosphere. The successful development of these methods paves the way for better understanding the nature of upper atmospheric variability introduced by tides. Comparison to models indicate that models generally underestimate the tidal amplitudes. Analysis of neutral composition variations is consistent with the theory that upward propagating tides influence the longitudinal structure of thermospheric composition.

We present the dielectric function of a bcc-In2O3 thin film in the wide spectral range from nearinfrared to vacuum-ultraviolet and for temperatures 10 K–300K, determined by spectroscopic ellipsometry. From the temperature dependence of electronic transition energies, we derive electron-phonon coupling properties and found hints that the direct parabolic band-band transitions involve In-d states. Further we discuss possible excitonic contributions to the dielectric function.

It is well-known that the performance of the CS process is enhanced by increasing the process gas stagnation temperature, as this increases the gas velocity, and thus the particle velocity (kinetic energy). However, the influence of the initial substrate, coating, and particle impact temperatures on the CS process performance is still a topic that has barely been studied. This work focuses on establishing in a more systematic way how the initial substrate, coating, and particle impact temperatures affect the CS process performance by decoupling these three variables from the general spray parameters, namely the gas stagnation temperature. This decoupling is of crucial importance if one wants to be able to study the effect of each temperature and this approach has never been reported anywhere so far. In this work, two feedstock powder materials are used: pure aluminum and Inconel 718. The substrate material selected is Ti-6Al-4V. Therefore, the observations provided in this thesis are valid for the deposition of aluminum-on-Ti-6Al-4V and Inconel718-on-Ti-6Al-4V. To increase and control the initial substrate and coating temperatures while ensuring proper decoupling of other spray parameters, an induction heating system is used with the CS process. To control the initial particle temperature, independently from the gas stagnation temperature, powder preheater units are used. The powder is fed in the diverging section of the nozzle to avoid the uncontrollable heating usually observed by feeding the powder in the converging section. Single-particle impact testing and splat adhesion strength testing are carried out to evaluate the effect of the initial substrate temperature on individual particles. This is investigated using pure aluminum as the feedstock powder material. A finite element modeling is also carried out to complement the experimental results. The influence of the initial substrate temperature on the deposition process is quantified by measuring the deposition efficiency and coating porosity values. Micro-hardness testing and adhesion strength testing are used to characterized the as-sprayed coating mechanical properties. To study the influence of the coating temperature on the CS process performance, both powders, pure aluminum and Inconel 718, are used. The role of the coating temperature on the CS process is assessed by measuring the deposition efficiency and coating porosity values for the deposition of both powders. Micro-hardness, adhesion, and tensile strength measurements of the pure aluminum coatings is carried out. For the Inconel 718 coatings, only micro-hardness testing is conducted. To characterize the influence of the particle impact temperature on the CS process, Inconel 718 is used. The particle impact temperature is predicted using a computational fluid dynamics model. Deposition efficiency, coating porosity values, and micro-hardness testing are used to characterize the influence of the particle impact temperature on the CS process. The results in this thesis provide a path to optimize the CS process performance based on the influence of the initial substrate, coating, and particle impact temperatures. This work also demonstrates that other variables, such as particle impact velocity and feedstock powder material hardness, must also be considered to optimize the CS process performance through the use of different temperatures.

No description available.

Daily temperature variations across an area can often be attributed to differences in land use/land cover (LULC). This study focuses on the relationships between the diurnal temperature ranges (DTRs) of 145 weather stations, classified as urban, agriculture, evergreen forests, deciduous forests, pine forests, and mixed forests. Paired samples t-tests were employed to test for significant DTR differences due to LULC type, season, and air mass type. Conflicting with previous research, agricultural areas reported the lowest DTRs, which may be due to the vegetation or to other physiographic variables. The forest types showed very few significant DTR differences. All of the LULC types experienced an annual bimodal DTR pattern, with peaks in April and October. Results of this study show that air mass has the largest influence on DTR (over LULC and season), therefore, the annual variability of air mass occurrence is most likely cause of the bimodal pattern.

No description available.

No description available.

No description available.