Results 81 to 90 of about 2,675 (308)

Characterization of a 100-kW Class Nested-Channel Hall Thruster

, 2018
The next generation of electric propulsion consists of systems in excess of 300 kW of power. These systems enable a wide variety of missions, including crewed missions to near-Earth asteroids and Mars.
Hall, Scott James
core  

A detailed redescription of a skeletally immature ‘Redondasaurus’ suggests ontogenetic transformations in the taxon mirror phytosaurian morphological evolution

The Anatomical Record, EarlyView.
Abstract The study of morphological evolution is fundamentally tied to ontogeny, yet studies of these heterochronic processes in the fossil record are rare. Fossils belonging to an ontogenetic series are difficult to assign to an ontogenetic stage due to inconsistent proxies for skeletal ages, challenging to taxonomically assign due to morphological ...
Erika R. Goldsmith, Michelle R. Stocker
wiley   +1 more source

NASA's 2004 Hall Thruster Program

, 2004
An overview of NASA's Hall thruster research and development tasks conducted during fiscal year 2004 is presented. These tasks focus on: raising the technology readiness level of high power Hall thrusters, developing a moderate-power/ moderate specific ...
Jacobson, David T., Peterson, Peter Y., Manzella, David H., Hofer, Richard R.   +3 more
core  

Altered by Gold: A Comparative Zooarchaeological Analysis of 19th to 20th Century Chinese and British Migrants in Ravenswood, a Northern Queensland Gold Mining Town

Archaeology in Oceania, EarlyView.
ABSTRACT Gold discoveries transformed the 19th century British colony of Queensland, Australia, driving migration, a second wave of pastoral expansion northwards, and an increasingly diverse population. This study presents a comparative and contextual zooarchaeological analysis of British and southern Chinese food waste—globally significant migrant ...
Marc Cheeseman
wiley   +1 more source

Study on inversion method of wall erosion information of on-orbit Hall thruster based on low-frequency oscillation signals and neural networks. [PDF]

Heliyon, 2022
Han K, Xie F, Wang Y, Zhang L, Yu M, Wang J, Wang Y, Wan J.   +7 more
europepmc   +1 more source

Challenges and Opportunities in Multi‐Method Integrated Geophysical Prospection of Buried Building Remains at the Sanctuary of Olympia

Archaeological Prospection, EarlyView.
ABSTRACT Ancient Olympia was one of the most important sanctuaries and the venue for the Olympic Games in Greek and Roman times. Its remains are located in the Olympia Terrace (Peloponnese, Greece) at the present‐day confluence of the rivers Alpheios and Kladeos at the base of Mount Kronos.
Sarah Bäumler, Dennis Wilken, Peter Fischer, Lena Slabon, Timo Willershäuser, Birgitta Eder, Hans‐Joachim Gehrke, Erofili‐Iris Kolia, Franziska Lang, Oliver Pilz, Andreas Vött   +10 more
wiley   +1 more source

Growth of Rayleigh instability in a Hall thruster channel having dust in exit region

AIP Advances, 2019
In a Hall thruster, the axial movement of ions towards the exit of the chamber and the divergence of ion beam sputter the wall and thus the maximum erosion of wall of the exit region takes place.
Hitendra K. Malik, Jasvendra Tyagi, Dimple Sharma   +2 more
doaj   +1 more source

Research on Thrust Noise Characteristic of 1.35kW Hall Thruster [PDF]

EPJ Web of Conferences
The rapid advancement of contemporary global satellite communication and navigation has led to a growing significance for accurate orbit prediction and real-time orbit control capabilities.
Keyuan Huang, Wei Mao, Yanming Wei, Xiufeng Zhong, Qi Liu, Nan Wu, Yanlin Hu   +6 more
doaj   +1 more source

Characterization of a 100-kW Class Nested-Channel Hall Thruster [PDF]

The next generation of electric propulsion consists of systems in excess of 300 kW of power. These systems enable a wide variety of missions, including crewed missions to near-Earth asteroids and Mars.
Hall, Scott
core  

Learning to ‘be’ an activist: Exploring the relationship between activism and informal education in a youth activism group case study

British Educational Research Journal, EarlyView.
Abstract Young people in the United States (and beyond) access spaces for activism in varied ways, including the out‐of‐school time sector, where youth activism (YA) groups draw on informal learning pedagogies to engage young people in collective action.
Laura Weiner
wiley   +1 more source