1,110 research outputs found
CCDC 1958147: Experimental Crystal Structure Determination
No full textRelated Article: Timothy R. Lex, Maria I. Swasy, Soham Panda, Beau R. Brummel, Lauren N. Giambalvo, Kristopher G. Gross, Colin D. McMillen, Khadijatul Kobra, William T. Pennington, Daniel C. Whitehead|2020|Tetrahedron Lett.|61|151723|doi:10.1016/j.tetlet.2020.15172
CCDC 955135: Experimental Crystal Structure Determination
No full textAn entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.,Related Article: Clyde R. Metz, Jennifer L. Radke, William G. Shuler, Marco Gattoni Celli, Colin D. McMillen, William T. Pennington, Charles F. Beam|2014|J.Chem.Cryst.|44|401|doi:10.1007/s10870-014-0529-
The Indian history of an American institution: Native Americans and Dartmouth
No full textAbout the Book
(from upne.com) Dartmouth College began life as an Indian school, a pretense that has since been abandoned. Still, the institution has a unique, if complicated, relationship with Native Americans and their history. Beginning with Samson Occom’s role as the first “development officer” of the college, Colin G. Calloway tells the entire, complex story of Dartmouth’s historical and ongoing relationship with Native Americans. Calloway recounts the struggles and achievements of Indian attendees and the history of Dartmouth alumni’s involvements with American Indian affairs. He also covers more recent developments, such as the mascot controversies, the emergence of an active Native American student organization, and the partial fulfillment of a promise deferred. This is a fascinating picture of an elite American institution and its troubled relationship— at times compassionate, at times conflicted—with Indians and Native American culture.
About the Author
(from upne.com) Colin G. Calloway is John Kimball Jr. 1943 Professor of History and Professor of Native American Studies at Dartmouth College. He is the author of numerous books, including One Vast Winter Count: The Native American West Before Lewis and Clark (2003), which won six best-book awards.
About the Electronic Publication
This electronic publication of The Indian History of an American Institution was made possible with the permission of the author. The University Press of New England created EPUB and PDF files from a scanned copy of the book.
Rights Information
Creative Commons Attribution-NonCommercial License © Trustees of Dartmouth Collegehttps://digitalcommons.dartmouth.edu/dartmouth_press/1004/thumbnail.jp
CCDC 909504: Experimental Crystal Structure Determination
No full textAn entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.,Related Article: Alton R. Thomas, William G. Shuler, Ellyn A. Smith, Sarah S. Carlisle, Shabree L. Knick, Andrew J. Puciaty, Clyde R. Metz, Donald G. VanDerveer, Colin D. McMillen, William T. Pennington and Charles F. Beam|2013|J.Chem.Cryst.|43|629|doi:10.1007/s10870-013-0458-
CCDC 909505: Experimental Crystal Structure Determination
No full textAn entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.,Related Article: Alton R. Thomas, William G. Shuler, Ellyn A. Smith, Sarah S. Carlisle, Shabree L. Knick, Andrew J. Puciaty, Clyde R. Metz, Donald G. VanDerveer, Colin D. McMillen, William T. Pennington and Charles F. Beam|2013|J.Chem.Cryst.|43|629|doi:10.1007/s10870-013-0458-
CCDC 890764: Experimental Crystal Structure Determination
No full textAn entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.,Related Article: Alton R. Thomas, William G. Shuler, Ellyn A. Smith, Sarah S. Carlisle, Shabree L. Knick, Andrew J. Puciaty, Clyde R. Metz, Donald G. VanDerveer, Colin D. McMillen, William T. Pennington and Charles F. Beam|2013|J.Chem.Cryst.|43|629|doi:10.1007/s10870-013-0458-
Underwater detection, classification and localisation: Improving the capabilities of towed sonar arrays
No full textThe end of the Cold War and the collapse of the Warsaw pact have resulted in a change of operational theatre for the naval forces of the North Atlantic Treaty Organisation (NATO). In particular, the focus of Anti Submarine Warfare forces has shifted from tracking Soviet nuclear ballistic missile submarine in the deep waters of the Atlantic ocean to hunting smaller and quieter Diesel electric submarines in coastal water. In most scenarios, towed array sonars are the best sensor to detect, classify and localise submarines. The long passive towed array sonars used during the Cold war are more difficult to use in coastal waters and are being replaced by most Navies by Low Frequency Active Sonars (LFAS) using a towed source and shorter towed receiving array. These shorter towed arrays can be used in both active and passive modes. In passive mode, their reduced size offer limited performance compared to their longer equivalent. In active mode, they can detect submarines at long ranges in shallow waters but are plagued by false alarms caused by echoes from features of the seafloor. This thesis deals with algorithms improving Detection, Classification and Localisation for towed sonar arrays, with a specific focus on LFAS sonars. In Chapter 2, we derive, analyse and apply to measured data a method for improving detection performance with short passive towed arrays. An important issue in detection of quiet acoustic source with short towed arrays is the improvement in signal-to-noise ratio (SNR) and bearing resolution for targets emitting low frequency signals. One of the techniques believed to improve these characteristics is Synthetic Aperture Sonar (SAS). The method is based on the artificial enlargement of a sonar array by coherently integrating acoustic snapshots at different antenna positions. We first derive theoretical measures of performance of passive SAS and report on its application in combination with other signal-processing algorithms. Its theoretical performance is compared with that of the frequently used incoherent integration. The used passive SAS algorithm is the method known as Extended Towed Array Measurement (ETAM) or the overlap correlator. It is based on the correlation of data snapshots on overlapping hydrophones. Correlation is a key issue in this method and since it is affected by noisy targets, some gain can be expected from noise cancellation. The influence on the performance of ETAM of a method of tow ship noise cancelling at hydrophone level (Inverse Beam Forming, IBF) is analysed. This approach increases ETAM performance by removing a loud and highly correlated noise source, the tow ship, and thus enhancing the other targets in the beam pattern. The results of the algorithms applied to two experimental datasets show that they bring an improvement close to theoretical expectations. Port starboard discrimination and the successful combination of IBF with ETAM make this approach innovative. In Chapter 3, methods for improving the localisation of a source with a short towed array are analysed and applied to data, both simulated and measured at sea. Localisation performance with sonar towed array is related to the array length. The knowledge of the position of a given acoustic source gives a critical tactical advantage to a ship. There are a limited number of ways to estimate the range of a source with a towed passive sonar, most requiring the towing platform to execute a manoeuvre. These manoeuvres are undesirable as they take a lot of time, cause bending of the towed array and can even put the towing platform in harm’s way. We present a number of source position estimation methods for both broadband and narrowband sources suitable for short towed arrays. Recursive methods based on the extended Kalman filter are first examined. A new method based on the integration of time delay of arrival measurements along the sonar path is described. We derive theoretical performance indicators and show that this method gives the possibility to estimate the position and speed of a source without a manoeuvre. In Chapter 4, the Classification performance of a broadband waveform is analysed and measured on data collected at sea. Like any long-range active sonar system, LFAS produces a large amount of unwanted sea bottom echoes or clutter. These echoes give rise to false alarms that increase the computational load of target trackers and jeopardise the correct classification of each echo. The number of false alarms due to clutter can be reduced either through echo classification techniques or through Doppler filtering provided the targets of interest are in motion. Much research has been carried out on waveform investigation for the efficient use of bandwidth capabilities of modern sonar transmitters. Among the quantity of waveforms, Binary Phase Shift Keyed (BPSK) pulses have emerged as exhibiting cross-correlation properties relevant to Doppler filtering while maintaining a range resolution comparable to Frequency Modulated (FM) pulses. We have successfully applied a false alarm reduction technique using contacts obtained with an FM pulse subsequently processed by Doppler filtering with a BPSK pulse. The Doppler classification performance for this pulse is evaluated on an experimental dataset and a few limitations of BPSK are identified.Aircraft Transport and OperationAerospace Engineerin
Orbit design for future SpaceChip swarm missions in a planetary atmosphere
No full textThe effect of solar radiation pressure and atmospheric drag on the orbital dynamics of satellites-on-a-chip (SpaceChips) is exploited to design equatorial long-lived orbits about the oblate Earth. The orbit energy gain due to asymmetric solar radiation pressure, considering the Earth's shadow, is used to balance the energy loss due to atmospheric drag. Future missions for a swarm of SpaceChips are proposed, where a number of small devices are released from a conventional spacecraft to perform spatially distributed measurements of the conditions in the ionosphere and exosphere. It is shown that the orbit lifetime can be extended and indeed selected through solar radiation pressure and the end-of-life re-entry of the swarm can be ensured, by exploiting atmospheric drag
Figure S12 in Supplementary Materials for Precipitation is the main axis of tropical plant phylogenetic turnover across space and time
No full textFigure S12 (lef). Numbers of taxa per alignment.Published as part of Jens J. Ringelberg, Erik J. M. Koenen, Benjamin Sauter, Anahita Aebli, Juliana G. Rando, João R. Iganci, Luciano P. de Queiroz, Daniel J. Murphy, Myriam Gaudeu, Anne Bruneau, Melissa Luckow, Gwilym P. Lewis, Joseph T. Miller, Marcelo F. Simon, Lucas S. B. Jordão, Matías Morales, C. Donovan Bailey, Madhugiri Nageswara-Rao, James A. Nicholls, Oriane Loiseau, R. Toby Pennington, Kyle G. Dexter, Niklaus E. Zimmermann & Colin E. Hughes, 2023, Supplementary Materials for Precipitation is the main axis of tropical plant phylogenetic turnover across space and time, pp. 2-111 in Science Advances (suppl.) 9 on page 64, DOI: 10.5281/zenodo.787182
Figure S6 in Supplementary Materials for Precipitation is the main axis of tropical plant phylogenetic turnover across space and time
No full textFigure S6 (lef). Fractions of duplicated reads per sample.Published as part of Jens J. Ringelberg, Erik J. M. Koenen, Benjamin Sauter, Anahita Aebli, Juliana G. Rando, João R. Iganci, Luciano P. de Queiroz, Daniel J. Murphy, Myriam Gaudeu, Anne Bruneau, Melissa Luckow, Gwilym P. Lewis, Joseph T. Miller, Marcelo F. Simon, Lucas S. B. Jordão, Matías Morales, C. Donovan Bailey, Madhugiri Nageswara-Rao, James A. Nicholls, Oriane Loiseau, R. Toby Pennington, Kyle G. Dexter, Niklaus E. Zimmermann & Colin E. Hughes, 2023, Supplementary Materials for Precipitation is the main axis of tropical plant phylogenetic turnover across space and time, pp. 2-111 in Science Advances (suppl.) 9 on page 62, DOI: 10.5281/zenodo.787182
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