A multi-disciplinary, high resolution, geophysical investigation of a Scottish Sea loch has facilitated both the reconstruction of a detailed late Quaternary para-stratigraphic model and the critical assessment of the acquisition and analytical methodologies most appropriate for the study of submerged palaeo-glaciomarine environments. Loch Ainort, situated on the eastern coast of the Isle of Skye, has been surveyed using a 192 kHz echosounder, a 400 kHz side scan sonar and a 3.5 kHz sub-bottom profiler. Lithological calibration was provided by the analysis of both in situ core data and extant terrestrial data sets. It is proposed that for the effective reconstruction of these and any other nearshore palaeo-environments a multi-disciplinary geophysical approach is essential. The critical control on success is the adherence, during interpretation, to a single unifying seismo-analytical framework. The seismo-stratigraphical analysis technique has been adapted for high- resolution work in order to provide this rigid framework. Objective descriptive analysis of the seismic traces provides a "seismic para-stratigraphy" which when combined with lithological data is used to construct a "composite para-stratigraphy". This is a process based, litho-stratigraphic interpretation that, by virtue of the detailed spatial extent afforded it by geophysical data, can be placed in a wider environmental context. The composite para-stratigraphy for the Loch Ainort basin is dominated by Loch Lomond Stadial glacial activity. Terminal and readvance limits are identified at several localities within the basin. Variable morphological styles of the glacial sequences show that deglaciation occurred in two distinct, climatically controlled, phases. The first marked by a fluctuating ice margin and the second by uninterrupted retreat and in situ ice stagnation. Sub-aerially induced debris flows occur during the initial paraglacial phase but stabilisation of exposed slopes restricts this input and rapid sedimentation of fines from sediment-rich meltwaters becomes dominant. Modern fjordic sedimentation develops after the disappearance of glacier ice.

Part one (also issued separately)--is S.G. Bergquist's Thesis (Ph. D.) University of Michigan. / "Published as part of the annual report of the Geological Survey Division for 1936." Bibliography: p. [139]-140, 218-219, [255]-256.

Part one (also issued separately)--is S.G. Bergquist's Thesis (Ph. D.) University of Michigan. / "Published as part of the annual report of the Geological Survey Division for 1936." Bibliography: p. [139]-140, 218-219, [255]-256.

Part 1 is Glenn Charles Tague's Thesis (Ph. D.)--University of Michigan; part 2 is James Lewis Calver's thesis (Ph. D.) University of Michigan. / "Published as part of the annual report of the Geological Survey Division for 1946." Includes bibliographical references (p. 80, 68).

Thesis--University of Colorado. / Includes bibliographical references (p. [291]-304).

Thesis (M.S.)--University of Wisconsin--Madison, 1967. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

abstract: The Universe transitioned from a state of neutral hydrogen (HI) shortly after recombination to its present day ionized state, but this transition, the Epoch of Reionization (EoR), has been poorly constrained by observational data. Estimates place the EoR between redshifts 6 < z <13 (330-770 Myr). The interaction of the 21 cm hyperfine ground state emission/absorption-line of HI with the cosmic microwave background (CMB) and the radiation from the first luminous sources in the universe can be used to extract cosmological information about the EoR. Theorists have created global redshifted 21 cm EoR models of this interaction that predict the temperature perturbations to the CMB in the form of a sky-averaged difference temperature, Tb. The difficulty in measuring Tb is that it is predicted to be on the order of 20 to 100 mK, while the sky foreground is dominated by synchrotron radiation that is 105 times brighter. The challenge is to subtract the much brighter foreground radiation without subtracting the Tb signal and can only be done when the data has small error levels. The Experiment to Detect the Global EoR Signature (EDGES) is an effort to measure Tb with a single wide field-of-view well-calibrated antenna. This dissertation focuses on reducing systematic errors by quantifying the impact of the chromatic nature of the antenna’s beam directivity and by measuring the variability of the spectral index of the radio sky foreground. The chromatic beam study quantified the superior qualities of the rectangular blade-shaped antenna and led to its adoption over the previously used fourpoint-shaped antenna and determined that a 5 term polynomial was optimum for removing the foreground. The spectral index, β, of the sky was measured, using 211 nights of data, to be −2.60 > β > −2.62 in lower LST regions, increasing to −2.50 near the Galactic plane. This matched simulated results using the Guzm´an et al. (2011) sky map (∆β < 0.05) and demonstrated the exceptional stability of the EDGES instrument. Lastly, an EoR model by Kaurov & Gnedin (2016) was shown to be inconsistent with measured EDGES data at a significance level of 1.9. / Dissertation/Thesis / Doctoral Dissertation Astrophysics and Astronomy 2017

The Pliocene, a geologic epoch spanning ~2.6-5.3 million years ago (Ma), was a period in Earth’s history where temperatures were several degrees warmer than today and atmospheric CO2 was close to modern levels, making it an analogue for future climate change. Following this interval, the planet’s climate shifted to the familiar glacial-interglacial cycles of the Pleistocene (~0-2.6 Ma), beginning with the development of extensive Northern Hemisphere ice sheets at ~2.7 Ma. In response to these changes through the Plio-Pleistocene, several components of the Earth System, particularly related to East Asia and the North Pacific Ocean, varied both temporally and spatially, further modifying regional and global climate through various feedbacks. In this thesis, I utilize a combination of geochemical proxies derived from North Pacific marine sediments as well as a regional climate model to better understand the evolution of the westerly winds, North Pacific Ocean circulation, and East Asian desert landscapes, across the last five million years. In Chapter 1, I reconstruct Pliocene dust fluxes at two different sites in the North Pacific using the constant flux proxy extraterrestrial 3He (3HeET), the first of such records in the Pliocene. Along with 3HeET-derived export productivity fluxes and sea surface temperatures from the westernmost core, I show that the Northern Hemisphere westerly winds, were shifted poleward and weaker during much of the warm Pliocene. Coinciding with the intensification of Northern Hemisphere Glaciation, the westerlies shifted equatorward and strengthened at ~2.7 Ma, and during subsequent glacial periods thereafter. Combining my dust flux record with others from different ocean basin, I find that these changes in the westerly winds were globally synchronous. Chapter 2, entitled “Pliocene Variability of Active Pacific Meridional Overturning Circulation: Reevaluating North Pacific Productivity and Redox Conditions from ~2.5-6 Ma”, presents additional 3HeET-based export productivity flux data, as well as redox element concentrations, from the central subarctic North Pacific through the Pliocene. The new records suggest elevated North Pacific export production during the interval spanning ~4-5.5 Ma, followed by a decrease in the mid-Pliocene (~3.5-4 Ma). Combining this new data with previously published records and modeling output, I provide additional evidence for an active Pacific meridional overturning circulation during the warmer-than-present Pliocene, and add constraints on its variability under various climatic conditions. In Chapter 3, I bring together two constant flux proxy-derived dust flux datasets from the same core in the western North Pacific Ocean to provide novel insight into Quaternary dust dynamics in East Asia. By utilizing constant flux proxies, and accounting for inputs of volcanic material, I show for the first time that dust input to the North Pacific decreased over the last ~2.7 Myr, particularly during glacial periods. While quite different from other previously published dust datasets, this finding is consistent with our current understanding of East Asian dust production mechanisms, and acts as a strong impetus to perform more comprehensive studies of dust fluxes to the North Pacific and other depositional areas downwind of arid regions. Chapter 4 transitions to a terrestrial setting, in which I investigate the impacts of shifting arid region surface albedo on the atmospheric boundary layer using the Hami Basin, China, as a test location. Combining new simulations from the Weather Research and Forecasting base model and available geologic data, I report a previously undescribed “wind-albedo-wind” feedback process. Specifically, I propose that wind erosion, in conjunction with surficial sediments of various albedos, leads to altered wind speeds, and eventually fluctuations in erosion itself. In Chapter 5, I expand upon the work in the preceding chapter by coupling the Weather Research and Forecasting model with a chemistry component to simulate dust emissions. In addition, along with albedo, I characterize previously interpreted surface changes through time to reflect shifts in erodibility and surface roughness. I conclude that although albedo does ultimately influence near-surface wind speeds and dust emissions as predicted in my earlier study, the effects of variable surface roughness and erodibility dominate. Integrating these results with an updated interpretation of the geologic evolution of the Hami Basin, we find that during various periods of the last ~700 ky, the Hami Basin, and likely the greater stony Gobi Desert, could have been much more important dust sources than today.

abstract: The universe since its formation 13.7 billion years ago has undergone many changes. It began with expanding and cooling down to a temperature low enough for formation of atoms of neutral Hydrogen and Helium gas. Stronger gravitational pull in certain regions caused some regions to be denser and hotter than others. These regions kept getting denser and hotter until they had centers hot enough to burn the hydrogen and form the first stars, which ended the Dark Ages. These stars did not live long and underwent violent explosions. These explosions and the photons from the stars caused the hydrogen gas around them to ionize. This went on until all the hydrogen gas in the universe was ionized. This period is known as Epoch Of Reionization. Studying the Epoch Of Reionization will help understand the formation of these early stars, the timeline of the reionization and the formation of the stars and galaxies as we know them today. Studying the radiations from the 21cm line in neutral hydrogen, redshifted to below 200MHz can help determine details such as velocity, density and temperature of these early stars and the media around them. The EDGES program is one of the many programs that aim to study the Epoch of Reionization. It is a ground-based project deployed in Murchison Radio-Astronomy Observatory in Western Australia. At ground level the Radio Frequency Interference from the ionosphere and various man-made transmitters in the same frequency range as the EDGES receiver make measurements, receiver design and extraction of useful data from received signals difficult. Putting the receiver in space can help majorly escape the RFI. The EDGES In Space is a proposed project that aims at designing a receiver similar to the EDGES receiver but for a cubesat. This thesis aims at designing a prototype receiver that is similar in architecture to the EDGES low band receiver (50-100MHz) but is significantly smaller in size (small enough to fit on a PCB for a cubesat) while keeping in mind different considerations that affect circuit performance in space. / Dissertation/Thesis / Masters Thesis Electrical Engineering 2019

Moon Island, one of 180 drumlins in the Boston, Massachusetts area, is composed of a compact, clayey till with the southeastern slope of the drumlin forming a cliff caused by marine erosion. Samples of pebbles from the cliff-face and drumlin surface show horizontal stratification of till units that are differentiated by pebble size. The stratification is interpreted as evidence that the drumlin was formed in two stages: (1) one or more ice advances or surges which deposited the size-distinctive till layers. Stratigraphic variation of pebble lithologies in the till indicates that the till layers were probably deposited by at least two different ice lobes, and (2) an ice advance which carved the drumlin form without distorting or reshaping the horizontal till layers.Ball State UniversityMuncie, IN 47306