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B M Oliver

Publications and source records attributed to B M Oliver.

5 recordsLinked to original sources
PubMed1990

A review of interstellar rocketry fundamentals.

To reach even the nearest stars in a human lifetime requires a ship speed that is a substantial fraction of the speed of light. This means an enormous kinetic energy investment in the ship and suggests that maximizing the efficiency may be more important than minimizing the mass ratio. This paper develops the pertinent relativistic rocket equations and finds the conditions for high kinematic efficiency. Using the limiting efficiency of 100%, the minimum energy needed for one-way and for round trip voyages, and to explore all "good" suns out to a given distance, using pre-fueled rockets, is determined. Savings due to refueling the rocket (and reloading propellant) at the destination and in flight are both somewhat greater than 2:1.

Mathematics↗
PubMed1982

The influence of lip thickness and strain on upper lip response to incisor retraction.

Placement of teeth according to accepted cephalometric criteria does not necessarily ensure that overlying soft tissue will drape in a harmonious manner. The purpose of this research was to investigate the influence of maxillary lip thickness and lip strain on the relationship between dental and integumental tissue changes in orthodontically treated patients. Data were derived from pretreatment and retention lateral cephalometric head films of forty Caucasian subjects with Class II, Division 1 malocclusions. All patients were treated with edgewise appliances. Percentile groups were created for males and females according to the magnitude of maxillary lip thickness and lip strain. It was found that there was significant correlation between osseous changes and soft-tissue changes in both males (r= 0.83, p less than 0.01) and females (r = 0.85, p less than 0.01). Strong correlations were found between osseous changes and soft-tissue changes in subjects with thin lips (males, r equal to 0.92, p less than 0.01; females, r = 0.98, p less than 0.01), whereas no significant correlations were found in subjects with thick lips. Significant correlations were found between incisor changes and vermillion border changes in males (r = 0.61, p less than 0.01) and females (r = 0.51, p less than 0.05). Correlations were strong between incisor changes and vermilion border changes in subjects with high lip strain (males, r equal 0.92, p less than 0.01; females, r = 0.82, p less than 0.05) but were significant in subjects with low lip strain.

Adolescent↗
PubMedDate not supplied

The windows of SETI--frequency and time in the search for extraterrestrial intelligence.

On Earth intelligent life evolved as a natural consequence of the events set in motion when the planet formed over 4 billion years ago. Since chemical evolution and solar-system formation appear to be occurring throughout the universe, we theorize that our universe may be rich with planets populated by intelligent beings who, like us, can search for evidence of other technological civilizations. Terrestrial civilization now has this capability. But if we do not begin the search soon, we'll lose the opportunity to do it from Earth as interfering signals of Earthly origin rapidly close the microwave window.

Astronomical Phenomena↗