Kinetic resolution of racemic {alpha}-olefins with ansa-zirconocene polymerization catalysts: Enantiomorphic site vs. chain end control

Copolymerization of racemic {alpha}-olefins with ethylene and propylene was carried out in the presence of enantiopure C1-symmetric ansa metallocene, {1,2-(SiMe2)2({eta}5-C5H-3,5-(CHMe2)2)({eta}5-C5H3)}ZrCl2 to probe the effect of the polymer chain end on enantioselection for the R- or S-{alpha}-olefin during the kinetic resolution by polymerization catalysis. Copolymerizations with ethylene revealed that the polymer chain end is an important factor in the enantioselection of the reaction and that for homopolymerization, chain end control generally works cooperatively with enantiomorphic site control. Results from propylene copolymerizations suggested that chain end control arising from a methyl group at the beta carbon along the main chain can drastically affect selectivity, but its importance as a stereo-directing element depends on the identity of the olefin

Sputtering Holes with Ion Beamlets

Ion beamlets of predetermined configurations are formed by shaped apertures in the screen grid of an ion thruster having a double grid accelerator system. A plate is placed downstream from the screen grid holes and attached to the accelerator grid. When the ion thruster is operated holes having the configuration of the beamlets formed by the screen grid are sputtered through the plate at the accelerator grid

Preliminary design of graphite composite wing panels for commercial transport aircraft

Subjectively assessed practical and producible graphite/epoxy designs were subjected to a multilevel screening procedure which considered structural functions, efficiency, manufacturing and producibility, costs, maintainability, and inspectability. As each progressive screening level was reviewed, more definitive information on the structural efficiency (weight), manufacturing, and inspection procedures was established to support the design selection. The configuration features that enhance producibility of the final selected design can be used as a generic base for application to other wing panel designs. The selected panel design showed a weight saving of 25 percent over a conventional aluminum design meeting the same design requirements. The estimated cost reduction in manufacturing was 20 percent, based on 200 aircraft and projected 1985 automated composites manufacturing capability. The panel design background information developed will be used in the follow-on tasks to ensure that future panel development represents practical and producible design approaches to graphite/epoxy wing surface panels

Habit, aggregation and long memory: evidence from television audience data

Many economic outcomes appear to be influenced by habit or commitment, giving rise to persistence. In cases where the decision is binary and persistent, the aggregation of individual time series can result in a fractionally integrated process for the aggregate data. Certain television programmes appear to engender commitment on the part of viewers and the decision to watch or not is clearly binary. We report an empirical analysis of television audience data and show that these series can be modelled as I(d) processes. We also investigate the proposition that temporal aggregation of a fractionally-integrated series leaves the value of d unchanged.

Changes in Imja Tsho in the Mount Everest Region of Nepal

Imja Tsho, located in the Sagarmatha ( Everest) National Park of Nepal, is one of the most studied and rapidly growing lakes in the Himalayan range. Compared with previous studies, the results of our sonar bathymetric survey conducted in September of 2012 suggest that its maximum depth has increased from 90.5 to 116.3 +/- 5.2 m since 2002, and that its estimated volume has grown from 35.8 +/- 0.7 to 61.7 +/- 3.7 million m(3). Most of the expansion of the lake in recent years has taken place in the glacier terminus-lake interface on the eastern end of the lake, with the glacier receding at about 52 m yr(-1) and the lake expanding in area by 0.04 km(2) yr(-1). A ground penetrating radar survey of the Imja-Lhotse Shar glacier just behind the glacier terminus shows that the ice is over 200 m thick in the center of the glacier. The volume of water that could be released from the lake in the event of a breach in the damming moraine on the western end of the lake has increased to 34.1 +/- 1.08 million m(3) from the 21 million m(3) estimated in 2002.USAID Climate Change Resilient Development (CCRD) projectFulbright FoundationNational Geographic SocietyCenter for Research in Water Resource

Vol. 1 Ch. 7 The Collective Burial Locale Site A Critical Archaeological Feature in the Ohio Middle Woodland Period

https://ideaexchange.uakron.edu/encountering_hopewell/1006/thumbnail.jp

Homogenous Learning Styles Among Airport Management Professionals

Research on the career paths of airport management professionals included an assessment of learning styles to better understand the psychological profile of those in this career field. The Kolb Learning Styles Inventory, Version 3 (LSI-3) was used for the study for participants to self-assess their preferences for learning. General research on the validity and reliability of the (LSI-3) indicates that a roughly equal number of the general population categorize themselves in one out of four categories (Accommodators, Assimilators, Convergers, or Divergers). In the research involving airport management professionals, more than two-thirds of the respondents categorized themselves as Divergers. Another 22% categorized themselves as Accommodators. With almost 90% of the sample population represented within two of the four LSI groups, the evidence strongly suggests that airport management professionals prefer to learn by carefully evaluating definitive outcomes in a social environmental as opposed to action-based experimentation. Curiously, these results are diametrically opposite of similar research for another aviation related career path - military pilots, most of whom (44.2%) categorized themselves as Convergers (Kanske, 1999). This research may have implications in aviation education, particularly for recognizing that some students in collegiate aviation programs may have learning styles that are aligned with airport management professionals as opposed to other technically oriented aviation careers (e.g., commercial pilot). This understanding may be helpful in counseling students, particularly those struggling to find an aviation career path that better fits their preferred learning environment

From Cahokia to Larson to Moundville: Death, World Renewal, and the Sacred in the Mississippian Social World of the Late Prehistoric Eastern Woodlands

https://trace.tennessee.edu/utk_newfound-ebooks/1001/thumbnail.jp