Amounts of mineral N obtained by a calculation procedure and measurement in fallow plots were compared during two cropping seasons and annually with eight Oklahoma soils. The calculation procedure involved adjusting the N mineralization potentials for varying soil temperature and water content. The field N measurements involved the use of soil in plastic bags and glass filter tubes. Cropping season and annual field amounts for the eight soils, on the average, ranged from 54 to 78 ppm N. In general, the calculated amounts compared favorably to the field amounts, differences frequently being <10 ppm N. Calculated amounts correlated as well or better with the field amounts than a variety of other N availability indexes.

The need for new innovative technologies to support humanitarian action is evident today. Efficient and economic technologies properly deployed and integrated should mitigate some of the potential negative social effects of poor refugee camp infrastructure engineering. The body of the paper identifies off-grid solar Photovoltaic (PV) and solar PV hybrid packaged systems that are applicable to emergency relief activities, refugee camp activities and micro-grid development. The paper's concentration on offgrid power, the description of these engineered systems by humanitarian activity and the identification of the different engineered packaged solutions is aimed at stimulating a discussion to help scale more appropriate technologies for humanitarian action. The paper concludes with a discussion of present and future private sector business strategies to support scalability of this new and growing market.

A new space power concept incorporating earth -to-satellite microwave power beams coupled to onboard regenerative electrochemical energy storage is proposed for energizing defensive satellite constellations. The system addresses housekeeping, orbital maneuvering and burst mode power requirements, and offers an attractive alternative to the nuclear and solar space power systems currently envisioned for this application. This energy-conversion system incorporates six steps:(1) generate primary DC power at surface stations along the satellite ground-track, (2) convert to microwave (RF) frequencies, (3) transmit in a narrow beam to spacecraft using phased -array antennas which track and lock -on to satellite receivers as they pass in range during a fraction of their orbit, (4) receive the energy and convert to DC in space using lightweight and inexpensive rectennas; (5) store the energy onboard as chemical energy by electrolysis of water to oxygen and hydrogen and (6) recover free energy onboard the spacecraft during the balance of the orbit continuously or on demand as pulsed power with a high power-density fuel cell. Component and overall systems considerations of this scheme are discussed in comparison with alternatives, outstanding research problems are defined and preliminary analyses are described. These include orbital mechanics and ground tracks of satellites, accessibility of orbiters to microwave beams, transmission efficiencies, electronic and mechanical designs of the transmitter and rectenna, regenerative fuel cell energy storage, power conditioning and thermal management. The development of readily space -deployable rectennae, their supporting structures, and high specific power solid oxide monolithic fuels cells are the main pacing technologies leading to a wholly non -nuclear space power system capable of supporting all defensive satellite power requirements.

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