Advanced control concepts

The selection of a trim solution that provides the space shuttle with the highest level of performance and dynamic control in the presense of wind disturbances and bias torques due to misalignment of rocket engines is described. It was determined that engine gimballing is insufficient to provide control to trim the vehicle for headwind and sidewind disturbances, and that it is necessary to use aerodynamic surfaces in conjunction with engine gimballing to achieve trim. The algebraic equations for computing the trim solution were derived from the differential equations describing the motion of the vehicle by substituting the desired trim conditions. The general problem of showing how the trim equations are derived from the equations of motion and the mathematical forms of the performance criterion is discussed in detail, along with the general equations for studying the dynamic response of the trim solution

To assess the value of satellite photographs in resource evaluation on a national scale

The author has identified the following significant results. The limit of resolution on ERTS imagery is normally acknowledged to be about 60 miles although very long features such as roads and railways which are often less than 10 miles long are easily detectable. An example is the north-south road and railway from Lobatse to Francistown. Vegetation growth from winter to summer is readily monitored on false color imagery. The limits of government ranches and special farming areas can be quite accurately ascertained from ERTS imagery. Another aspect to which ERTS imagery lends itself is the location and demarcation of bush fires, many of which were seen on the first imagery which was acquired at the end of the cold, dry season. As a whole, MSS 7 offers maximum reflectance contrast among black and white imagery and is the wavelength used most for interpretation

Quasi-optimum design of a six degree of freedom moving base simulator control system

The design of a washout control system for a moving base simulator is treated by a quasi-optimum control technique. The broad objective of the design is to reproduce the sensed motion of a six degree of freedom simulator as accurately as possible without causing the simulator excursions to exceed specified limits. A performance criterion is established that weights magnitude and direction errors in specific force and in angular velocity and attempts to maintain the excursion within set limits by penalizing excessive excursions. A FORTRAN routine for relizing the washout law was developed and typical time histories using the washout routine were simulated for a range of parameters in the penalty- and weighting-functions. These time histories and the listing of the routine are included in the report

Entanglement Generation in the Scattering of One-Dimensional Particles

This article provides a convenient framework for quantitative evaluation of the entanglement generated when two structureless, distinguishable particles scatter non-relativistically in one dimension. It explores how three factors determine the amount of entanglement generated: the momentum distributions of the incoming particles, their masses, and the interaction potential. Two important scales emerge, one set by the kinematics and one set by the dynamics. This method also provides two approximate analytic formulas useful for numerical evaluation of entanglement and reveals an interesting connection between purity, linear coordinate transformations, and momentum uncertainties.Comment: 11 pages, submitted to PR

Third sector organizations and earthquake recovery planning in Christchurch, New Zealand

On September 4, 2010, an earthquake struck rural Canterbury and the most deadly of over 2,000 aftershocks devastated the Christchurch Central Business District on February 22, 2011 (Ardagh et al. 2012). Questions have arisen regarding population dynamics (Love 2011), marginalized groups, health and social care, and overall recovery efforts. Addressing some of these concerns are various non-profit, non-governmental, and faith based groups, collectively referred to as Third Sector Organizations (TSOs). By providing an alternative to and back-stopping government and private health and social services, TSOs are able to build resiliency following a natural disaster, and are especially able to identify and address unmet needs within their target audiences and maintain a sense of community within their operating areas. The nature of community recovery, also changes the role of TSOs in formal and grassroots efforts over time. In New Zealand, TSOs have shared community health burdens with government and private practices since the 1990s (Larner and Craig 2005) and have championed healthcare policy measures for ethnic minorities (Came 2014). Nevertheless, the earthquakes have presented challenges to TSOs. An inventory of 92 TSOs four months after the earthquakes, 106 one year after, and 454 two years after by Carlton and Vallance (2013) shows that although many TSOs have emerged to address earthquake related issues, other TSOs may have been unable to re-establish themselves outside areas with earthquake damage found to be too severe to inhabit by the Canterbury Earthquake Recovery Authority (CERA). Others reported “burn-out” and 52 were inactive or closed because of shifting needs during recovery. This research identifies shared experiences across the third sector in Canterbury to illuminate shifting roles in mid to long-term earthquake recovery