Stratigraphic Relationships of the Brentwood and Woolsey Members, Bloyd Formation (Type Morrowan), Northwest Arkansas

The Brentwood Member of the Bloyd Formation conformably overlies the Prairie Grove Member, Hale Formation in the type Morrowan succession of northwestern Arkansas. At its type locality, the Brentwood is separated from the underlying Prairie Grove Member by nearly 6 m of dark shale. Away from this area, the shale thins rapidly and the Hale-Bloyd boundary may be placed with difficulty. At some localities east of type section, the boundary is thought to be erosional rather than the more typical gradational contact. The Brentwood consists of discrete carbonate bodies separated by dark shales. The carbonates consist principally of open shelf deposits, such as crinozoan biosparites and oolites. All carbonate lithologies contain varying amounts of fine to medium grained, rounded, quartz sand. Regionally, the Brentwood Member becomes more shaly to the west of its type locality and loses the quartz sand content in its carbonate lithologies. To the east, the Brentwood shales become less prominent and quartz sandstone intervals characterize the succession. The Woolsey Member overlies the Brentwood Member and consists of light to dark, argillaceous shales with occasional sandstones, carbonates, and a thin coal. The coal is confined essentially to Washington and northern Crawford counties and never exceeds 45.7 cm. The shales are thought to be of terrestrial origin, but marine fossils and thin limestones in the lower part of typical Woolsey strata indicate a transitional change within the member rather than at its base. In contrast, the detrital fraction of the upper Brentwood carbonates seem to decrease rather than increase towards the Woolsey contact. To the west of the type area, the Woolsey gives rise to marine shales and carbonates. To the east, the Woolsey is equivalent to a thick, quartz pebble-bearing sandstone of fluvial origin. The top of the Woolsey Member is a regional unconformity with the overlying Dye Shale Member, Bloyd Formation

Nucleation and crystallisation of hafnium compounds and thin films

Hafnia and hafnium silicate are leading high-κ materials to replace SiO2 in CMOS devices. In this thesis the results of a study of bulk powders and thin films of these materials are reported. Bulk powders were investigated to provide a greater understanding of the crystallisation process by which HfO2 and HfSiO4 are formed. Investigation using thermal analysis, xray diffraction and electron microscopy techniques revealed that starting materials, heating conditions and atmosphere significantly affected the crystallisation pathway. In particular three mechanisms for tetragonal hafnia (t-HfO2) stabilisation were identified: (1) oxygen vacancies; (2) the critical particle size effect; and (3) the surface energy effect. Electron energy-loss spectroscopy (EELS) was used to try to obtain a standard O K edge for t-HfO2 from the powders and to better understand experimental EELS spectra obtained from thin films. A standard t-HfO2 edge was not found and many of the spectra obtained did not match existing standard edge shapes. The local atomic environment has a large effect on the edge shape in these samples, leading to the conclusion that a ‘standard’ edge shape may be impossible to obtain. Combining the EELS spectra from bulk and thin film samples, with modelled data it was found that the atoms within ~6Å from the excited atom had the largest effect on the edge shape. Consequently EELS spectra taken at a distance from an interface greater than ~6Å will give a bulk-like signal. 20nm HfxSi1-xO2 thin films were also investigated using TEM having been subjected to different thermal anneals and deposition conditions. It was found that the electron beam caused significant growth of SiO2 layers due to oxygen diffusion, and crystallisation within the high-κ layer. Furthermore, the higher the SiO2 content in the sample the more crystallisation was inhibited, though segregation into HfO2 and SiO2 rich regions occurred in all samples.

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Darla walked down High Street, her heels clicking a rapid beat, her normally pleasant face marred by a frown

1863-06-23 Major P. McGilvery of the Mounted Artillery recommends Lieutenant William H. Gallison for a position in the 1st Maine Heavy Artillery

https://digitalmaine.com/cw_me_1st_heavy_corr/1085/thumbnail.jp

1864-03-20 William McGilvery and other citizens of Waldo County request promotion of Llewellyn Lincoln

https://digitalmaine.com/cw_me_4th_regiment_corr/1492/thumbnail.jp

A Prograding Margin during Global Sea-Level Maxima: An Example from Mahajanga Basin, Northwest Madagascar

The Mesozoic shelf margin in the Mahajanga Basin, northwest Madagascar, provides an example where inherited palaeobathymetry, coupled with sea-level changes, high sediment supply and fluctuations in accommodation influenced the stacking patterns and geometry of clinoforms that accreted onto a passive rifted margin. Two-dimensional (2D) seismic profiles are integrated with existing field data and geological maps to study the evolution of the margin. The basin contains complete records of transgression, highstand, regression and lowstand phases that took place from Jurassic to Cretaceous. Of particular interest is the Cretaceous, Albian to Turonian (ca. 113-93 Ma), siliciclastic shelf margin that prograded above a drowned Middle Jurassic carbonate platform. The siliciclastic phase of the shelf margin advanced ca. 70 km within ca. 20 My, and contains 10 distinct clinoforms mapped along a 2D seismic reflection data set. The clinoforms show a progressive decrease in height and slope length, and a fairly constant slope gradient through time. The successive shelf edges begin with a persistent flat to slightly downward-directed shelf-edge trajectory that changes to an ascending trajectory at the end of clinoform progradation. The progressive decrease in clinoform height and slope length is attributed to a decrease in accommodation. The prograding margin is interpreted to have formed when siliciclastic input increased as eastern Madagascar was uplifted. This work highlights the importance of sediment supply and inherited palaeobathymetry as controls on the evolution of shelf margins and it provides a new understanding of the evolution of the Mahajanga Basin during the Mesozoic

Advanced nanoanalysis of a Hf-based high-<i>k</i> dielectric stack prior to activation

Analytical electron microscopy techniques are used to investigate elemental distributions across a high-&lt;i&gt;k&lt;/i&gt; dielectric stack with a metal gate. Electron energy-loss spectroscopy results from a Si(100)/SiO2/HfO2/TiN/a-Si gate stack confirm the presence of an oxide interfacial phase at the TiN/a-Si interface prior to activation of the stack

A Compact 3H(p,gamma)4He 19.8-MeV Gamma-Ray Source for Energy Calibration at the Sudbury Neutrino Observatory

The Sudbury Neutrino Observatory (SNO) is a new 1000-tonne D2O Cerenkov solar neutrino detector. A high energy gamma-ray source is needed to calibrate SNO beyond the 8B solar neutrino endpoint of 15 MeV. This paper describes the design and construction of a source that generates 19.8-MeV gamma rays using the 3H(p,gamma)4He reaction (``pt''), and demonstrates that the source meets all the physical, operational and lifetime requirements for calibrating SNO. An ion source was built into this unit to generate and to accelerate protons up to 30 keV, and a high purity scandium tritide target with a scandium-tritium atomic ratio of 1:2.0+/-0.2 was included. This pt source is the first self-contained, compact, and portable high energy gamma-ray source (E>10 MeV).Comment: 33 pages (including 2 table, 12 figures) This is the revised manuscript, accepted for publication in NIM A. This revision relfects minor editorial changes from the previous versio

Effect of proofreading on mechanics and structure of writing--grades four, five, six

Thesis (M.A.)--Boston Universit