MM and subMM molecular line observations of the southwest lobe of L1551: Evidence of a shell structure

Observations have been made of the southwest outflow lobe of L1551 in several millimeter and submillimeter molecular lines. Maps have been made in the J=3-2 and J=2-1 transitions of CO over areas of 7.5 by 2.5 arc minutes and 5 by 5 arc minutes respectively at UKIRT. More detailed maps have also been made in the J=2-1 CO transition over an area of about 6 by 3.5 arc minutes at the NRAO 12m telescope. Additional observations of the J=4-3 transitions of HCN, HCO(+) abd H(13)CO(+) were made at selected positions. The HC(+) J=4-3 transition was detected at several positions along the outflow axis and at the position of IRS 5. Similarly the HCN J=4-3 transition was detected at the position of IRS 5 and also at a position close to HH29. However, the J=4-3 transition of H(13)CO(+) was bit detected at the position of IRS 5 even through it was observed at the position close to HH29 with a peak corrected antenna temperature of 0.23K at a V(LSR) of 1 km s(-1). The detection of the J=4-3 transitions of both HCO(+) and H(13)CO(+) close to the position of HH29 suggest the presence of very dense gas in this region. LVG analysis of the various molecular lines observed give a kinetic temperature between 10 and 15K and a density from 10(5) to 10(6) cm(-3) at the position of IRS 5 at the ambient cloud velocity. At the position close to HH29 LVG analysis of the CO observations gives a density between 10(3) and 10(4) cm(-3) at a kinetic temperature of 25k for a V(LSR) of 0 km s(-1). To the southwest of HH29 there is a large decrease in both the linewidth and intensity of CO emission. This may be due to the interaction between the outflow and a dense clump of gas which gives rise to HH29. The maps of the CO J=3-2 and CO J=2-1 emission integrated in 3.25 km s intervals show the shell structure postulated by Snell and Schloerb (1985)

Development of an Engineering Diagram for Additively Manufactured Austenitic Stainless Steel Alloys

Austenitic stainless steels are the most widely applied types of stainless steels, due to their good weldability and high corrosion resistance. A number of engineering diagrams exist for the purpose of providing insight into the behavior of these steels. Examples of these diagrams are constitution diagrams (aka Schaeffler Diagrams) which are used to approximate the solidification path of the alloy and the amount of retained ferrite in the solidified matrix. Other diagrams are the Suutala diagram, which approximates cracking susceptibility, and microstructural maps, which predict the solidification path by varying a processing parameter, such as cooling rate. By combining these diagrams, a much more concrete conclusion can be made as to the behavior of a particular steel. This approach could be used to determine differences in behaviors between two different compositions. The developed diagram would be intended for use with rapid solidification phenomena as observed in the selective laser melting process

M dwarf stars in the light of (future) exoplanet searches

We present a brief overview of a splinter session on M dwarf stars as planet hosts that was organized as part of the Cool Stars 17 conference. The session was devoted to reviewing our current knowledge of M dwarf stars and exoplanets in order to prepare for current and future exoplanet searches focusing in low mass stars. We review the observational and theoretical challenges to characterize M dwarf stars and the importance of accurate fundamental parameters for the proper characterization of their exoplanets and our understanding on planet formation.Comment: 4 pages, 1 figure. Summary of the splinter session "M dwarf stars in the light of (future) exoplanet searches" held at the 17th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun, June 28th 2012, Barcelona, Spain. Submitted for publication in Astronomische Nachrichten - Astronomical Notes (AN) 334, Issue 1-2, Eds Klaus Strassmeier and Mercedes L\'opez-Morale

The Mississippi River System Shallow Draft Barge Market – Perfectly Competitive or Oligopolistic?

Most transportation textbooks and articles on inland waterway navigation assume a perfectly competitive Mississippi River system barge industry. One study found the 1972 and 1977 grain barge industry to be oligopolistic. A second study of the U.S. barge industry found "intra industry competition for the barge industry on a day-to-day basis with easy entry and exit." Using the concentration ratio and the Herfindahl Index, this study found the Mississippi River barge industry to be oligopolistic. These results suggest that Mississippi River navigation infrastructure studies should not use long run marginal barge costs as a proxy for barge rates

Cost-savings achieved in two semesters through the adoption of open educational resources

Textbooks represent a significant portion of the overall cost of higher education in the United States. The burden of these costs is typically shouldered by students, those who support them, and the taxpayers who fund the grants and student loans which pay for textbooks. Open educational resources (OER) provide students a way to receive high-quality learning materials at little or no cost to students. We report on the cost savings achieved by students at eight colleges when these colleges began utilizing OER in place of traditional commercial textbooks

Millimetre and submillimetre molecular line observations of the southwest lobe of L 1551 - evidence of a shell structure

Observations have been made of the southwest outflow lobe of L 1551 in several millimetre and submillimetre molecular lines. Maps have been made in the J = 3-2 and J = 2-1 transitions of CO over areas of 7.5 by 2.5 arcmin and 5 by 5 arcmin respectively, using the 3.8 m United Kingdom Infrared Telescope (UKIRT). Higher angular resolution maps have also been made in the J = 2-1 CO transition over an area of about 6 by 3.5 arcmin with the NRAO 12 m telescope, and additional observations of the J = 4-3 transitions of HCN, HCO+, and H13CO+ were obtained towards selected positions. The observations, showing a shell structure, an accelerating outflow and possible rotation of the outflowing gas, suggest that the Sweeping-Magnetic-Twist model of Uchida and Shibata is the most appropriate of currently available models of bipolar sources, to explain the L 1551 bipolar outflow