586 research outputs found
The growth of paracoccus halodenitrificans in a defined medium
A synthetic medium, consisting of inorganic salts and any of a number of carbon sources, supported the aerobic growth of Paracoccus halodenitrificans when supplemented with thiamine. The same medium plus a nitrogenous oxide supported anaerobic growth when additionally supplemented with methionine. The observation that vitamin B12 or betaine replaced methionine suggested that P. halodenitrificans had a defect in the cobalamin dependent pathway for methionine biosynthesis, as well as the inability to synthesize betaine when growing anaerobically
Modeling of pulsed propellant reorientation
Optimization of the propellant reorientation process can provide increased payload capability and extend the service life of spacecraft. The use of pulsed propellant reorientation to optimize the reorientation process is proposed. The ECLIPSE code was validated for modeling the reorientation process and is used to study pulsed reorientation in small-scale and full-scale propellant tanks. A dimensional analysis of the process is performed and the resulting dimensionless groups are used to present and correlate the computational predictions for reorientation performance
The effect of sterilization on biological, organic geochemical and morphological information in natural samples
The loss of biological, organic geochemical, and morphological science information that may occur should a Mars surface sample be sterilized prior to return to earth is examined. Results of experimental studies are summarized
STS-1 operational flight profile. Volume 5: Descent, cycle 3
The trajectory data presented are to be used for orbiter systems and subsystems evalation, flight and mission control center software verification, flight techniques and timeline development, crew training, and evaluation of operational mission suitability. The entry profile is very similar to cycle 2, however, elevon and body flap temperature margins have increased and the elevon schedule was changed. The terminal area energy management (TAEM) profile was completely reshaped to conform with new angle of attack constraints and left hand turn around the heading alignment cylinder. Also, the entry/TAEM interface was adjusted to minimize guidance induced angle of attack transients across the interface. The approach and landing phase was reshaped for a 20 deg glideslope and reduced velocity at touchdown. The definition of the runway threshold was standardized for all landing sites. This results in a shift at Edwards Air Force Base in aim points and touchdown relative to the threshold of 1000 feet. The rollout remains essentially unchanged with the exception of the speedbrake, which is now deployed to 50 percent at touchdown
Is the customer king?
Sales and service staff need to consider and influence a portfolio of relationships, not only customers, write Willy Bolander, Christopher R. Plouffe, Joseph A. Cote and Bryan Hochstei
Earthquake Monitoring and Response from Space: The TREMOR Concept
Earthquakes and their after-effects claim thousands of lives and cause enormous property damage each year. Early warning of impending seismological events has the potential to reduce human suffering and physical damage resulting from these natural disasters. Reliable earthquake precursors have yet to be identified, but some research is currently being performed into phenomena that could be observable from space. Satellites have been unquestionably beneficial in the response to earthquakes, providing essential communication and remote sensing support. The Technological Resources for Earthquake MOnitoring and Response (TREMOR) concept was initially developed as a team project at the 2007 International Space University Summer Session Program. It recommends the establishment of an international non-governmental organization that can more efficiently co-ordinate space-based and ground-based resources for the protection of human lives and property. The TREMOR concept is explored further here, concentrating on its use of space technology to minimize the economic and human impact of earthquakes. Updated cost estimates for TREMOR satellite mission concepts are also presented
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Unsteady flow phenomena in human undulatory swimming: a numerical approach
The undulatory underwater sequence is one of the most important phases in competitive swimming. An understanding of the recurrent vortex dynamics around the human body and their generation could therefore be used to improve swimming techniques. In order to produce a dynamic model, we applied human joint kinematics to three-dimensional (3D) body scans of a female swimmer. The flow around this dynamic model was then calculated using computational fluid dynamics with the aid of moving 3D meshes. Evaluation of the numerical results delivered by the various motion cycles identified characteristic vortex structures for each of the cycles, which exhibited increasing intensity and drag influence. At maximum thrust, drag forces appear to be 12 times higher than those of a passive gliding swimmer. As far as we know, this is the first disclosure of vortex rings merging into vortex tubes in the wake after vortex recapturing. All unsteady structures were visualized using a modified Q-criterion also incorporated into our methods. At the very least, our approach is likely to be suited to further studies examining swimmers engaging in undulatory swimming during training or competition
Improved earthquake response via simulation and integrated space- and ground-based technologies: the TREMOR proposal
Earthquakes occurring around the world each year cause thousands of
deaths, millions of dollars in damage to infrastructure, and incalculable
human suffering. In recent years, satellite technology has been a
significant boon to response efforts following an earthquake and its
after-effects by providing mobile communications between response teams
and remote sensing of damaged areas to disaster management organizations.
In 2007, an international team of students and professionals assembled
during the
International Space University’s Summer Session Program in Beijing, China
to examine how satellite and ground-based technology could be better
integrated to provide an optimised response in the event of an earthquake.
The resulting Technology Resources for Earthquake MOnitoring and Response
(TREMOR) proposal describes an integrative prototype response system that
will implement mobile satellite communication hubs providing telephone and
data links between response teams, onsite telemedicine consultation for
emergency first-responders, and satellite navigation systems that will
locate and track emergency vehicles and guide search-and-rescue crews. A
prototype earthquake simulation system is also proposed, integrating
historical data, earthquake precursor data, and local geomatics and
infrastructure information to predict the damage that could occur in the
event of an earthquake. The backbone of these proposals is a comprehensive
education and training program to help individuals, communities and
governments prepare in advance. The TREMOR team recommends the
coordination of these efforts through a centralised, non-governmental
organization
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