5,768 research outputs found
Elis and Leo B. Leonard at U. S. Army reception at the Fort Lewis Officers\u27 Club
No full textPhoto of a U. S. Army reception at the Fort Lewis Officers\u27 Club, attended by Leo and Elis Leonard in 1947 or 1948
The fast debris evolution model
No full textThe ‘Particles-in-a-box’ (PIB) model introduced by Talent (1992) removed the need for computer-intensive Monte Carlo simulation to predict the gross characteristics of an evolving debris environment. The PIB model was described using a differential equation that allows the stability of the low Earth orbit (LEO) environment to be tested by a straightforward analysis of the equation’s coefficients. As part of an ongoing research effort to investigate more efficient approaches to evolutionary modelling and to develop a suite of educational tools, a new PIB model has been developed. The model, entitled Fast Debris Evolution (FADE), employs a first-order differential equation to describe the rate at which new objects ?10 cm are added and removed from the environment. Whilst Talent (1992) based the collision theory for the PIB approach on collisions between gas particles and adopted specific values for the parameters of the model from a number of references, the form and coefficients of the FADE model equations can be inferred from the outputs of future projections produced by high-fidelity models, such as the DAMAGE model. The FADE model has been implemented as a client-side, web-based service using JavaScript embedded within a HTML document. Due to the simple nature of the algorithm, FADE can deliver the results of future projections immediately in a graphical format, with complete user-control over key simulation parameters. Historical and future projections for the ?10 cm low Earth orbit (LEO) debris environment under a variety of different scenarios are possible, including business as usual, no future launches, post-mission disposal and remediation. A selection of results is presented with comparisons with predictions made using the DAMAGE environment model. The results demonstrate that the FADE model is able to capture comparable time-series of collisions and number of objects as predicted by DAMAGE in several scenarios. Further, and perhaps more importantly, its speed and flexibility allows the user to explore and understand the evolution of the space debris environment<br/
Leo Leonard, Fort Lewis, Washington, 1947
No full textPhoto of Leo Leonard standing in front of the Red Shield Inn, officers\u27 quarters and guest house at Fort Lewis, Washington, about 1947. Reverse side of photograph: Ft. Lewis, Washington 194
Captain Leo Leonard in U. S. Army uniform, Ft. Lewis, Washington, 1947
No full textPhoto of Captain Leo Leonard in U. S. Army uniform at Fort Lewis, Washington, 1947. Item from Leo Leonard Scrapbook (black cover), 1935 to 1957
Captain Leo Leonard, Provost Marshal in U. S. Army uniform, Ft. Lewis, Washington
No full textPhoto of Captain Leo Leonard, Provost Marshal, in U. S. Army uniform, Ft. Lewis, Washington, 1947. Reverse side of photograph: Ft. Lewis, Wash 194
Leo Leonard, Provost Marshal in U. S. Army uniform, Ft. Lewis, Washington, 1947
No full textPhoto of Provost Marshal Leo Leonard in U. S. Army uniform, at Fort Lewis, Washington, about 1947. Note on reverse side of photograph: Ft. Lewis, Washington, 194
U. S. Army reception at the Fort Lewis Officers\u27 Club
No full textPhoto of a U. S. Army reception at the Fort Lewis Officers\u27 Club, attended by Leo and Elis Leonard in 1947 or 1948
Captain Leo Leonard, Provost Marshal in U. S. Army uniform, Ft. Lewis, Washington
No full textPhoto of Captain Leo Leonard, Provost Marshal, in U. S. Army uniform, Ft. Lewis, Washington, 1947. Reverse side of photograph: Ft. Lewis, Wash 194
Leo Leonard in U. S. Army uniform, Ft. Lewis, Washington, 1947
No full textPhoto of Leo Leonard in U. S. Army uniform, at Fort Lewis, Washington, about 1947. Note on reverse side of photograph: Ft. Lewis, Washington, 194
Captain Leo Leonard, Provost Marshal in U. S. Army uniform, Ft. Lewis, Washington
No full textPhoto of Captain Leo Leonard, Provost Marshal, in U. S. Army uniform, Ft. Lewis, Washington, 1947
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