154 research outputs found
A Paleomagnetic Analysis of the Deformation and Hydrothermal Alteration in the Killarney Igneous Complex, Ontario
No full textTitle: A Paleomagnetic Analysis of the Deformation and Hydrothermal Alteration in the Killarney Igneous Complex, Ontario, Author: Andrew Wiacek, Location: ThodeThe Killarney Igneous Complex lies along the Grenville
Front, forming a wedge between the Grenville and Southern
Provinces of the Canadian Shield. The complex consists of a
granitic pluton and associated felsic volcanic rocks that
have been subjected to both mid-Proterozoic and Grenvillian
tectonism. This study sought paleomagnetic confirmation of
pre-Grenville deformation by carrying out AF and thermal
demagnetization experiments on 226 samples representing both
the massive and foliated parts of the complex. This was
accompanied by an analysis of polished thin-sections to
attempt to determine a paragenesis for the remanence
carrying minerals. Sixty-four specimens of foliated and veined, hematiteenriched
porphyry carry a stable southwesterly magnetization
(Declination= 242.4°, Inclination= -26.4°, K = 17.5, A95 =
11.2°) or its antipole. The paleomagnetic pole implied by
this magnetization (Longitude= 19.3°E, Latitude= 29.1°, dp
= 9.6°, dm = 10.9°) is consistent with an age of somewhat
less than 1100 Ma. This magnetization is a CRM that was
acquired during the hydrothermal alteration of the porphyry.
As a consistent magnetization is carried by highly sheared
rocks as well as the hematite-enriched porphyry, it is concluded that the shearing must have occurred prior to the
hydrothermal event. Thus, the onset of Grenville tectonism
in the Killarney region began before 1100 Ma. Sufficient
paleomagnetic evidence was not obtained to determine the
timing of pre-Grenville tectonism.ThesisMaster of Science (MS
À lire / À voir / À suivre
No full textHistoire de l’armée polonaise en France. L’alliance blessée 1939‑1940 Jacques Wiacek, Histoire de l’armée polonaise en France. L’alliance blessée 1939-1940, Louviers, YSEC, 2022, 448 p. Jacques Wiacek, “Histoire de l’armée polonaise en France” Après l’écrasement de la Pologne en 1939 par les troupes allemandes et russes, la France focalise tous les espoirs des Polonais. Un gouvernement en exil émerge à Paris, renouvelant une longue alliance entre les deux pays. Entre les mois d’octobre 1939 ..
Omega-3 fatty acids supplementation affects tryptophan metabolism during a 12-week endurance training in amateur runners – a randomized controlled trial
No full textThe effects of long-term omega-3 fatty acid (n-3 PUFAs) supplementation during endurance training on tryptophan (Trp) metabolism and mental state of healthy individuals have not been evaluated so far. Concentrations of plasma Trp, its metabolites and IL-6 were assessed in 26 male runners before and after a 12-week training combined with supplementation of n-3 PUFAs (O-3 + TRAIN group) or medium chain triglycerides (MCTs; TRAIN group). Mood and stress tests were also performed. The effects of the same supplementation protocol were evaluated also in 14 inactive subjects (O-3 + SEDEN group). Concentrations of 3-hydroxykynurenine (3-HK) and picolinic acid (PA) significantly increased only in the O-3 + TRAIN group (p = 0.01; η_p^2 = 0.22 and p = 0.01; η_(p )^2= 0.26). Favorable, but not statistically significant changes in the kynurenic acid (KYNA) (p = 0.06; η_(p )^2= 0.14), xanthurenic acid (XA) (p = 0.07; η_(p )^2= 0.13) and 3-hydroxyanthranilic acid (3-HAA) (p = 0.06; η_(p )^2= 0.15) and ratio of neurotoxic to neuroprotective metabolites was seen also only in the O-3 + TRAIN group. No changes in results of mental state tests and IL-6 concentrations were observed in either group. Supplementation with n-3 PUFAs during endurance training has beneficial effects on Trp's neuroprotective metabolites.<br/
Land- and water-only Level 3 products from MOPITT TIR-NIR Version 8 CO retrievals
No full textThis dataset contains alternative products to the official Level 3 (L3) product from Measurements of Pollution in the Troposphere (MOPITT) joint thermal infrared (TIR) – near infrared (NIR) Version 8 Carbon Monoxide (CO) retrievals (available here: https://doi.org/10.5067/TERRA/MOPITT/MOP03J_L3.008). The products are described and analysed in a paper in the journal Atmospheric Measurement Techniques by Ian Ashpole and Aldona Wiacek (2022, https://doi.org/10.5194/amt-2022-90).
In short, whereas the official MOPITT L3 product is based on retrievals performed over both land AND water surface types, the products here are created separately from retrievals performed ONLY over land (“L3L”) OR water (“L3W”). The code for creating L3L and L3W is available here: https://github.com/ianashpole/MOPITT_L3L_L3W
The version naming is consistent with the official MOPITT product version, although note that version 8 is the first version that these alternatives are produced for (i.e. although MOPITT product versions 1-7 exist, L3L and L3W do not). However, it is intended that L3L and L3W are created for MOPITT product versions after version 8.
The dataset stored here consists of two main .zip archives:
“MOPITT_v8.L3L.20010901_20190228.zip”
“MOPITT_v8.L3W.20010901_20190228.zip”
When unzipped, each archive contains 6057 individual NetCDF (".nc") files that correspond to the daily L3L and L3W data products for the period 2001-09-01 to 2019-02-28, inclusive. Daily files represent the satellite instrument measurements for a single day. Users are referred to the "README.txt" file for a full description of the individual file contents. Note that when unzipped, the products require ~22.5 GB of data storage each (45 GB total for both L3L and L3W). Because of this, a single file from each product has been uploaded separately (file date = “20020801”; see below for naming convention) to facilitate user experimentation before unpacking the full L3L/L3W products.
Individual L3L/L3W NetCDF files are ~3.4 MB in size.
The individual NetCDF files are named as follows:
MOPITT_v8.L3L.from_MOPO2J.selected_variables.YYYYMMDD.nc
(replace “L3L” with “L3W” in the filename for the corresponding L3W product.)
The date corresponds to the YYYYMMDD that the retrievals were made. E.g. the file “MOPITT_v8.L3L.from_MOPO2J.selected_variables.20020801.nc” corresponds to the L3L product for MOPITT retrievals made on August 1st 2002.
Variables contained within the file are described in detail in the "README.txt" file.
NetCDF is a common format for gridded geoscientific data, easily readable by all widely used scientific programming languages (e.g. Python, R, Matlab, IDL…), as well as dedicated command line tools (e.g. cdo, gdal). Panoply (https://www.giss.nasa.gov/tools/panoply/) is an alternative application for quickly plotting these data without the requirement of coding experience. Most GIS packages can also handle NetCDF data.
An example python code for reading and plotting data from a single L3L file is available here: https://github.com/ianashpole/MOPITT_L3L_L3W/blob/main/example_read_and_plot_MOPITT_L3L.ipynb</p
Development and optimisation of supercritical fluid deposition of semiconductor films
No full textThis thesis is concerned with the deposition, and characterisation, of semiconductor thin films and microstructures deposited from a supercritical fluid. Thin films of CdS, GaP, InP, InAs, and Ge were deposited using supercritical CO2 and CO2-solvent mixtures. Ge was deposited into macropores etched into crystalline silicon substrates. A variety of reactors were designed in order to achieve the successful deposition of the materials. The surface morphology and crystallinity of the films were characterised by scanning electron microscopy and X-ray diffraction. The chemical composition of the films was analysed by energy or wavelength dispersive X-ray spectroscopy, secondary ion mass spectroscopy, Auger electron spectroscopy, and X-ray photoelectron spectroscopy. The optoelectronic quality of the CdS and InP films was analysed by photoluminescence spectroscopy and mapping. The CdS films deposited were confirmed to be of hexagonal phase by X-ray diffraction and exhibited band edge luminescence. The InP and InAs films were determined to be of cubic structure and the InP films were found to exhibit weak band edge luminescence. The fabrication of macroporous silicon templates by photoelectrochemical etching is also discussed. Pores with diameters of between 60 nm and 2 µm were fabricated, having aspect ratios of up to 100:1. Ge was successfully deposited into macropores etched into these crystalline silicon templates with near conformal coverage
Energy resolution of a silicon detector with the RX64 ASIC designed for X-ray imaging
No full textResults from a silicon microstrip detector coupled to the RX64 ASIC are presented. The system is capable of single photon counting in digital X-ray imaging, with foreseen applications to dual energy mammography and angiography. The main features of the detecting system are low noise (operation with threshold as low as E4 keV is possible), good spatial resolution (a pixel of 100 mm 300 mm when oriented edge-on) and good counting rate capability (up to one million counts per channel with a maximum rate of about 200 kHz per channel). The energy resolution of the system, as obtained with several fluorescence X-ray lines, is described
Controls on the production of ground level ozone in Halifax, Nova Scotia
No full text1 online resource (96 p.) : colour illustrations, colour mapsIncludes abstract and appendices.Includes bibliographical references (p. 80-88).Atmospheric ozone (O3) is a secondary pollutant produced via complex chemical reactions involving precursors like nitrogen oxides (NOx), Volatile Organic Compounds (VOC) and carbon monoxide (CO). The key to reducing ozone concentrations is to regulate the precursors. Using data from the National Air Pollutant Surveillance (NAPS) program, possible controls on ozone production are examined for Halifax and other regions across Nova Scotia, including meteorological and chemical variables.Long-term trends of ozone and its precursors in Nova Scotia were analyzed to see the effect of emissions regulations across North America. Diurnal and monthly averages were also examined to show short-term patterns in Halifax. It was found that 1-hour average ozone levels are relatively steady in Halifax under decreasing NOx emissions, due to a reduction of the strong NOx titration effect on O3; however, Total Ozone (TO), comprised of O3 and NO2, is decreasing, along with maximum 1-hr ozone. Additionally, it was found that there are no strong signatures of biogenic VOC influence on ozone levels in Halifax (as opposed to anthropogenic VOC), although more frequent measurements of VOC are needed to better study VOC-sensitivity. There is indication from the high NOx levels that ozone production is on the whole VOC-sensitive in Halifax.Lastly, long-range transport was examined during an event of maximum elevated O3 at the background air Aylesford NAPS station in 2016. The high O3 levels were correlated with high values in Halifax and transport to both locations was consistent with pollutant import from the the northeast U.S. Flow to Halifax vs. Aylesford is in general more complicated because there is no obvious correlation between ozone in Halifax and at the Aylesford NAPS station, which requires further study.All of the above findings are policy-relevant in the regulation of ozone precursors
Bonner Sphere Spectrometry: main achievements from the “CONRAD Computational Dosimetry Study"
No full textComparison of first Saint Mary’s University Open-Path Fourier Transform Infrared (OP-FTIR) spectrometer measurement results with National Air Pollution Surveillance (NAPS) air quality measurements in Halifax
No full text1 online resource (171 p.) : ill. (chiefly col.), col. mapsIncludes bibliographical references (p. 167-171).Includes abstract and appendices.The atmosphere is very complex and it involves many chemical and physical processes that affect the air people breathe. This is why it is important to characterize the air in the atmosphere in order to determine what people are exposed to every day. Carbon monoxide (CO), a toxic air pollutant emitted primarily as a result of incomplete combustion and oxidation of hydrocarbons, was measured in Halifax, Nova Scotia using an Open-Path Fourier Transform Infrared (OP-FTIR) spectrometer and compared to National Air Pollution Surveillance (NAPS) CO measurements as a verification step in the characterization of this new instrument.
Measured NAPS data was compared to OP-FTIR spectrometer results for three different measurement campaigns: Robie Street (at Inglis for 2 hours), Rice Building (at SMU for ~1 week), and Lake Major (in Dartmouth for ~1 week). For each campaign, spectra were recorded and a concentration of CO was retrieved for each spectrum (one per minute) by the program MALT. The retrieved CO concentrations were plotted in a time series for each campaign and compared to NAPS CO concentration measurements obtained on Barrington Street at the same time.
Data quality of the OP-FTIR spectrometer was assessed in detail, with the majority of spectral fit residuals and their RMS values below 0.01 (1%), indicating a reasonable fit between the measured spectra and the fitted spectra simulated by MALT. The technique’s accuracy was previously conservatively estimated to be no worse than 10%; however, for all three campaigns, there was a clear systematic bias of up to 0.35 ppm (a factor of ~3) between the OP-FTIR spectrometer and NAPS measurements, along with unexplained enhancements in CO concentration at times and locations with minimal vehicle activity.
Further studies are suggested in order to fully explain the reason for the systematic bias and unusual enhancements in CO concentration observed
Recommended from our members
The use of bulky ligands for the stabilization of group 15 radicals and cations
No full texttextA variety of bulky ligands have been utilized for the stabilization of group
15 radicals and cations. The molecular structures of the stable phosphinyl and
arsinyl radicals, •
PnR2 (Pn = P, As; R = CH(SiMe3)2), have been determined by
gas-phase electron diffraction (GED) in conjunction with ab initio molecular
orbital calculations. The X-ray crystal structures of the corresponding dipnictines,
the "dimers", R2PnPnR2, and the corresponding chloro derivatives R2PnCl have
also been determined. Collectively, these gas-phase and solid-state structural
investigations demonstrate that large distortions of the ligands attached to
phosphorous and arsenic occur when the pnictinyl radicals unite to form the
corresponding dipnictine dimers. Theoretical studies indicate that in the process
of pnictinyl radical dimerization, the molecules accumulate substantial amounts of
potential energy and are thus primed to spring apart upon release from the solid
state by melting, dissolution, or evaporation.
The first example of group 15-containing “constrained geometry”
complexes, [Me2Si(η-C5Me4)(N-t-Bu)]PnCl (Pn = P, As, Sb), have been prepared
and isolated. In the case of the chlorophosphine, [Me2Si(η-C5Me4)(N-t-Bu)]PCl,
an unprecedented shift of the µ-SiMe2 group from the ipso to the α-position on the
Me4C5 ring occurs. Treatment of [Me2Si(η-C5Me4)(N-t-Bu)]PnCl (Pn = P, Sb)
with AlCl3 results in chloride ion abstraction and formation of the pnictocenium
salt, {[Me2Si(η-C5Me4)(N-t-Bu)]Pn}{AlCl4}. The structures of these salts were
established by X-ray crystallography.
The chloropnictines (η-C5Me5)2PnCl (Pn = As, Sb, Bi) have been
synthesized and structurally characterized, and exhibit the expected periodic trend
toward increased multihapto bonding with increasing atomic number. The
arsenocenium and stibocenium tetrachloroaluminates salts were prepared by
chloride anion abstraction from the precursor chlorides and the structures of the
cations in these salts were found to be different than those in previously reported
examples.Chemistry and Biochemistr
- …
