Development of single-cell protectors for sealed silver-zinc cells

Three design approaches to cell-level protection were developed, fabricated, and tested. These systems are referred to as the single-cell protector (SCP), multiplexed-cell protector(MCP). To evaluate the systems 18-cell battery packs without cell level control were subjected to cycle life test. A total of five batteries were subjected to simulate synchronous orbit cycling at 40% depth of discharge at 22C. Batteries without cell-level protection failed between 345 and 255 cycles. Cell failure in the cell level protected batteries occurred between 412 and 540. It was determined that the cell-level monitoring and protection is necessary to attain the long cycle life of a AgZn battery. The best method of providing control and protection of the AgZn cells depends on the specific application and capability of the user

Characterization of silicon dioxide for a capacitance-type meteoroid penetration detector

Fabrication and testing of large area metal oxide silicon capacitors for micrometeoroid counting in spac

The Value of the Civil Reserve Air Fleet: How Much Could the DoD Spend on Incentives?

This study evaluated the value of the Civil Reserve Air Fleet (CRAF) program to the DoD and explored the amount that could be spent to remove potential obstacles to participation with aviation insurance and lost market share. In comparing the value of the CRAF and the cost of current incentives, it was determined that up to $1.4 million could be spent on additional incentives, annually. For multiple aircraft losses and liability claims, the Air Force would need to tap into the Defense Business Operating Fund. Therefore, a sensitivity analysis was conducted and found that for low valued aircraft, such as the DC8, the cost due to loss would exceed the cost of commercial insurance at relatively low incident rates. Thus, it may be appropriate for the DoD to absorb the cost of commercial war risk insurance for certain missions, thereby eliminating the expense resulting from a large claim. The cost due to lost market share was measured by the minimum cost required to re-enter a city pair market. At highly desirable airports, this cost is approximately$51,200 per month. However, this research found no conclusive evidence that would warrant additional monetary incentives to reduce the risk of lost market share

Space station propulsion analysis study

This paper summarizes the impacts on the weight, volume and power usage of a manned space station and its 90-day resupply for three integrated, auxiliary propulsion subsystems. The study was performed in coordination with activities of the Space Staton Concept Development Group (CDG). The study focused on three space station propulsion high-low thrust options that make use of fluids that will be available on the manned space station. Specific uses of carbon dioxide, water and cryogen boiloff were considered. For each of the options the increase in station hardware mass and volume to accommodate the dual thrust option is offset by the resupply savings, relative to the reference hydrazine system, after one to several resupplies. Over the life of the station the savings in cost of logistics could be substantial. The three options are examples of alternative technology paths that, because of the opportunity they provide for integration with the environmental control life support system (ECLSS) and OTV propellant storage systems, may reduce the scarring which is required on the early station to meet the increasing propulsion requirements of the growth station

Square Integer Heffter Arrays with Empty Cells

A Heffter array $H(m,n;s,t)$ is an $m \times n$ matrix with nonzero entries from $\mathbb{Z}_{2ms+1}$ such that $i)$ each row contains $s$ filled cells and each column contains $t$ filled cells, $ii)$ every row and column sum to 0, and $iii)$ no element from $\{x,-x\}$ appears twice. Heffter arrays are useful in embedding the complete graph $K_{2nm+1}$ on an orientable surface where the embedding has the property that each edge borders exactly one $s-$cycle and one $t-$cycle. Archdeacon, Boothby and Dinitz proved that these arrays can be constructed in the case when $s=m$, i.e. every cell is filled. In this paper we concentrate on square arrays with empty cells where every row sum and every column sum is $0$ in $\mathbb{Z}$. We solve most of the instances of this case.Comment: 20 pages, including 2 figure

Using Empirical Information in the Era of HIV/AIDS to Inform Mitigation and Rural Development Strategies: Selected Results from African Country Studies

Community/Rural/Urban Development, Health Economics and Policy, Downloads July 2008-March 2009: 7,