Thermal Degradation and Corrosion of Amines for CO2 Capture

This report examines the thermal degradation and corrosion of various amine solvents as they apply to amine scrubbing for CO2 capture. Amines were placed in stainless steel cylinders and heated in convective ovens to simulate the stripping conditions inside a scrubbing unit. Samples were measured for remaining amine concentration, to test for degradation, and metals concentration, to estimate corrosion of the cylinder. The maximum stripping temperature of a particular compound, a measure of resistance to thermal degradation, strongly correlated with amine chain length. The linear amines studied had the following max temperatures: EDA (116 °C), PDA (124 °C), DAB (126 °C), BAE (130 °C), HMDA (140 °C), MEA (116 °C), MPA (129 °C), and DGA® (134 °C). The SHA/PZ blends had the following weighted max temperatures: AMP (143 °C), AMPD (135 °C), TRIS (130 °C), tBuAE (150 °C), PM (97 °C), and PE (129 °C). The linear amines follow initial first-order degradation curves, consistent with literature mechanisms. EDA, PDA, BAE, and AMP degraded significantly more slowly under acid conditions, suggesting that the degradation mechanisms do not incorporate CO2. Acid loaded DAB degraded at a similar rate to CO2-loaded conditions. MEA corroded 15 times faster than MPA; MAE corroded 3 times faster than EAE; DMAE-PZ corroded qualitatively faster than DMAP-PZ. These three pairs support the hypothesis that two-carbon chains corrode more than three-carbon chains. EDA corroded 40 to 80 times more than PDA according to older studies, seen in Figure 38, but more recent tests show similar corrosion rates where EDA is only 1.2 times faster (Figures 32 and 33). Corrosion and amine concentration correlate strongly; corrosion does not correlate strongly with temperature or CO2-loading. Corrosion and formate generation appear to correlate, supporting corrosion mechanisms proposed in literature.Chemical Engineerin

Star formation in Perseus. IV. Mass dependent evolution of dense cores

In our SCUBA survey of Perseus, we find that the fraction of protostellar cores increases towards higher masses and the most massive cores are all protostellar. In this paper we consider the possible explanations of this apparent mass dependence in the evolutionary status of these cores, and the implications for protostellar evolution and the mapping of the embedded core mass function (CMF) onto the stellar IMF. We consider the following potential causes: dust temperature; selection effects in the submillimetre and in the mid-infrared observations used for pre/protostellar classification; confusion and multiplicity; transient cores; and varying evolutionary timescales. We develop Core Mass Evolution Diagrams (CMEDs) to investigate how the mass evolution of individual cores maps onto the observed CMF. Two physical mechanisms -- short timescales for the evolution of massive cores, and continuing accumulation of mass onto protostellar cores -- best explain the relative excess of protostars in high mass cores and the rarity of massive starless cores. In addition, confusion both increases the likelihood that a protostar is identified within a core, and increases mass assigned to a core. The observed pre/protostellar mass distributions are consistent with faster evolution and a shorter lifetime for higher-mass prestellar cores. We rule out longer timescales for higher-mass prestellar cores. The differences in the prestellar and protostellar mass distributions imply that the prestellar CMF (and possibly the combined pre+protostellar CMF) should be steeper than the IMF. A steeper prestellar CMF can be reconciled with the observed similarity of the CMF and the IMF in some regions if a second opposing effect is present, such as the fragmentation of massive cores into multiple systems.Comment: 11 pages, 5 figures. Accepted by A&

Star formation in Perseus: III. Outflows

We present a search for outflows towards 51 submillimetre cores in Perseus. With consistently derived outflow properties from a large homogeneous dataset within one molecular cloud we can investigate further the mass dependence and time evolution of protostellar mass loss. Of the 51 cores, 37 show broad linewings indicative of molecular outflows. In 13 cases, the linewings could be due to confusion with neighbouring flows but 9 of those sources also have near-infrared detections confirming their protostellar nature. The total fraction of protostars in our sample is 65%. All but four outflow detections are confirmed as protostellar by Spitzer IR detections and only one Spitzer source has no outflow, showing that outflow maps at this sensitivity are equally good at identifying protostars as Spitzer. Outflow momentum flux correlates both with source luminosity and with core mass but there is considerable scatter even within this one cloud despite the homogeneous dataset. We fail to confirm the result of Bontemps et al. (1996) that Class I sources show lower momentum fluxes on average than Class 0 sources, with a KS test showing a significant probability that the momentum fluxes for both Class 0s and Class Is are drawn from the same distribution. We find that outflow power may not show a simple decline between the Class 0 to Class I stages. Our sample includes low momentum flux, low-luminosity Class 0 sources, possibly at a very early evolutionary stage. If the only mass loss from the core were due to outflows, cores would last for 10^5-10^8 years, longer than current estimates of 1.5-4 x 10^5 years for the mean lifetime for the embedded phase. Additional mechanisms for removing mass from protostellar cores may be necessary.Comment: 26 pages, 21 figures. Version with full colour figures from http://www.astro.ex.ac.uk/people/hatchell/RecentPapers/hatchell07_outflows.pd

Molecular line contamination in the SCUBA-2 450 {\mu}m and 850 {\mu}m continuum data

Observations of the dust emission using millimetre/submillimetre bolometer arrays can be contaminated by molecular line flux, such as flux from 12CO. As the brightest molecular line in the submillimetre, it is important to quantify the contribution of CO flux to the dust continuum bands. Conversion factors were used to convert molecular line integrated intensities to flux detected by bolometer arrays in mJy per beam. These factors were calculated for 12CO line integrated intensities to the SCUBA-2 850 {\mu}m and 450 {\mu}m bands. The conversion factors were then applied to HARP 12CO 3-2 maps of NGC 1333 in the Perseus complex and NGC 2071 and NGC 2024 in the Orion B molecular cloud complex to quantify the respective 12CO flux contribution to the 850 {\mu}m dust continuum emission. Sources with high molecular line contamination were analysed in further detail for molecular outflows and heating by nearby stars to determine the cause of the 12CO contribution. The majority of sources had a 12CO 3-2 flux contribution under 20 per cent. However, in regions of molecular outflows, the 12CO can dominate the source dust continuum (up to 79 per cent contamination) with 12CO fluxes reaching \sim 68 mJy per beam.Comment: Accepted 2012 April 19 for publication in MNRAS. 21 pages, 13 figures, 3 table

Closing The Gaps In United States Law And Implementing The rome Statute: A Comparative Approach

This paper provides a comparative framework to analyze the extent to which five major democracies Canada, United Kingdom, Australia, Germany, and France-incorporated the subject matter jurisdiction Articles of the Rome Statute of the International Criminal Court ( Rome Statute ) through their domestic legislative processes while ratifying the Rome Statute, and what, if anything, the United States can interpret from the five distinct approaches

The Training of our Recruits

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Sci-fi TV in the Great White North : the development of Vancouver as a science fiction media capital

Over the past three decades, Vancouver has emerged as a favorable destination for Hollywood television productions. Many academics have noted this trend as a result of industrial shifts within Hollywood, favorable economic conditions in Canadian locales, and a cultural proximity between the United States and Canada. Concurrently, Vancouver has also become a destination for many of Hollywood’s science fiction television productions. This thesis explores how the multi-channel transition of the Hollywood television industry cultivated a high-demand for content production and ultimately led to a wave of science fiction, horror, and supernatural productions in Vancouver. Through historical accounts of the television industry and discourse analysis of the industry’s trade press, this study tracks major industrial milestones that led to the rise of science fiction television production in the 1990s and early 2000s. Due to the strategies employed by three key distribution outlets—Fox, The WB, and Sci Fi—and the studios partnered with them, the rise in production of science fiction television in Vancouver points to the industrial significance in Hollywood’s development of the Canadian city into a genre-inflected media capital.Radio-Television-Fil