A near-earth optical communications terminal with a corevolving planetary sun shield

The umbra of a planet may serve as a sun shield for a space based optical communications terminal or for a space based astronomical observatory. An orbit that keeps the terminal or observatory within the umbra is desirable. There is a corevolution point behind every planet. A small body stabilized at the planet corevolution point will revolve about the sun at the same angular velocity as the planet, always keeping the planet between itself and the sun. This corevolution point is within the umbra of Mars but beyond the end of the umbra for Mercury, Venus, and earth. The Mars corevolution point is an ideal location for an astronomical observatory. There Mars obstruct less than 0.00024 percent of the sky at any time, and it shades the observatory completely from the sun. At the earth corevolution point, between 51 and 84 percent of the solar disk area is blocked, as is up to 92 percent of the sunlight. This provides a reduction from 3 dB to 11 dB in sunlight that could interfere with optical communications if scattered directly into the detectors. The variations is caused by revolution of the earth about the earth-moon barycenter

Fraunhofer filters to reduce solar background for optical communications

A wavelength that lies within a spectral interval of reduced solar emission (a Fraunhofer line) can carry optical communications with reduced interference from direct or reflected background sunlight. Suitable Fraunhofer lines are located within the tuning range of good candidate lasers. The laser should be tunable dynamically to track Doppler shifts in the sunlight incident on any solar system body that may appear in the background as viewed by the receiver. A Fraunhofer filter used with a direct-detection receiver should be tuned to match the Doppler shifts of the source and background. The required tuning calculated here for various situations is also required if, instead, one uses a heterodyne receiver with limited post-detection bandwidth

Developing an inter-university partnership: The importance of relationally-connected leaders

We have been involved in an inter-university partnership that supports, contributes to, and influences our own and others’ thinking and actions. As we have collaborated on teaching, learning, and research in the field of educational leadership, we recognise that we have developed our own leadership practice and created opportunities for others to do so. The partnership in which academics and students from the University of Central Oklahoma and the University of Waikato have been participating has evolved as a flexible and innovative endeavor over an eighteen month period. In this relatively brief time, we have discovered there are considerable possibilities for the partnership to be developed in a number of ways that will benefit academics, students, and our respective institutions. In this paper, we examine and discuss the findings generated by our initial inquiry as we seek to make sense of our inter university partnership in order to sustain and progress it. Our leadership during the initial phases of the partnership appears to have been a key element in its success. We have found that the presence of a relational connectedness has influenced and enhanced our own leadership practice and subsequently the quality of the partnership. It has enabled us to facilitate the growth of a community of practice and generate academic collaboration

Challenging US Country of Origin Labelling at the World Trade Organization: The Law, The Issues and The Evidence

Canada and Mexico are formally challenging US country of origin (COOL) legislation at the World Trade Organization. The industries most affected by COOL are beef and pork. The effect of COOL on North American cross border supply chains is outlined. The areas of international trade law upon which a challenge could be mounted are explained and the key issues that a disputes panel would have to determine indicated. The nature of the evidence that may be required to bolster Canada’s case is outlined.country of origin, marks of origin, protectionism, Technical Barriers to Trade, supply chains, WTO, Agribusiness, Agricultural and Food Policy, Demand and Price Analysis, International Relations/Trade, Marketing,

Challenging US Country of Origin Labelling at the WTO: The Law, the Issues and the Evidence

COOL, WTO, labelling, despite, Agricultural and Food Policy, International Relations/Trade,

Shutters and slats for the integral sunshade of an optical reception antenna

Optical reception antennas used at a small Sun-Earth-probe angle (small solar elongation E) require sunshading to prevent intolerable scattering of light from the surface of the primary mirror. An integral sunshade consisting of hexagonal tubes aligned with the segmentation of a large mirror was proposed for use down to E = 12 degrees. For smaller angles, asterisk-shaped vanes inserted into the length of the hexagonal tubes would allow operation down to about 6 degrees with a fixed obscuration of 3.6 percent. Two alternative methods are investigated to extend the usefulness of the integral sunshade to smaller angles by adding either variable-area shutters to block the tube corners that admit off-axis sunlight or by inserting slats (partial vanes) down the full length of some tubes. Slats are effective for most operations down to 6 degrees, and obscure only 1.2 percent. For E between 10.75 and 12 degrees, shutters cause even less obscuration