Evaluation of wind tunnel performance testings of an advanced 45 deg swept 8-bladed propeller at Mach numbers from 0.45 to 0.85

The increased emphasis of fuel conservation in the world and the rapid increase in the cost of jet fuel has stimulated a series of studies of both conventional and unconventional propulsion systems for commercial aircraft. The results of these studies indicate that a fuel saving of 15 to 30 percent may be realized by the use of an advanced high-speed turboprop (Prop-Fan) compared to aircraft equipped with high bypass turbofan engines of equivalent technology. The Prop-Fan propulsion system is being investigated as part of the NASA Aircraft Energy Efficient Program. This effort includes the wind tunnel testing of a series of 8 and 10-blade Prop-Fan models incorporate swept blades. Test results indicate efficiency levels near the goal of 80 percent at Mach 0.8 cruise and an altitude of 10.67 km (35,000 ft). Each successive swept model has shown improved efficiency relative to the straight blade model. The fourth model, with 45 deg swept blades reported herein, shows a net efficiency of 78.2 at the design point with a power loading of 301 kW/sq meter and a tip speed of 243.8 m/sec (800 ft/sec.)

Seed policy in Mozambique

Sorghum and Millet Improvement Program (SMIP) recently completed a review of seed policies in Mozambique in collaboration with the national Ministerio da Agricultura e Desenvolvimento Rural and Michigan State University. This study estimates Mozambique is annually losing up to US $77 million in productivity gains from the failure of the national seed system to disseminate new varieties of grain and grain legume crops currently identified on the national registration list. This includes an annual loss of US$14 million resulting from the failure to disseminate improved varieties of sorghum and pearl millet. Substantially larger sums are being lost if one considers the complementary costs of continuing food insecurity and poverty

Socioeconomics in SMIP: Research Highlights, Impacts, and Implications

This review of some of the major products of the SADC/ICRISAT Sorghum and Millet Improvement Program's (SMIP) economics research looks at: the economics research mandate; grain market research; evaluating industry demand; rural markets; the impact of sorghum and pearl millet dehullers; adoption and impact studies; crop breeding programmes; seed market analysis; regional seed policies; fertility management research; and human resource development. Implications for future research are discussed

Sorghum and pearl millet production in southern Africa

Sorghum and pearl millet are SADC's second and third most important cereal grains in terms of production area. Farmers in southern Africa annually sow over 1.9 million ha of sorghum and 0.9 million ha of pearl millet (Table 1). This compares with an aggregate production area of 12 million ha of maize. The area sown to sorghum and pearl millet in SADC has generally been increasing with the growth of smallholder farming populations

Development Options for Local Seed Systems in Mozambique. Working Paper Series no. 5

Large quantities of free or subsidized seed have been distributed to small-scale farmers in Mozambique under postwar resettlement and drought/flood relief programs. A joint study by ICRISAT and World Vision assessed the impact of relief seed distribution, the adoption of new varieties distributed through relief programs, and the performance of local seed systems. While there was undoubtedly a need for well-targeted emergency assistance, seed losses associated with war, drought, and floods appear to have been overestimated. Village seed systems are remarkably efficient in meeting seed requirements and maintaining varietal diversity, even under drought or flood conditions. However, there remains scope for improving household seed selection and storage practices. In addition, sustainable seed supply systems (both community-level and commercial) are needed to improve the access of small-scale farmers to new varieties. Despite the massive demand for seed for public distribution efforts, domestic production capabilities remain small, and most seed is still imported. The problems include shortages of breeder seed, poor market infrastructure, high marketing costs, uncertainty about levels of commercial seed demand, and farmer dependence on free seed. Specific recommendations are offered for strengthening both local and commercial seed supply systems in Mozambique

Single microtubules and small networks become significantly stiffer on short time-scales upon mechanical stimulation

The transfer of mechanical signals through cells is a complex phenomenon. To uncover a new mechanotransduction pathway, we study the frequency-dependent transport of mechanical stimuli by single microtubules and small networks in a bottom-up approach using optically trapped beads as anchor points. We interconnected microtubules to linear and triangular geometries to perform micro-rheology by defined oscillations of the beads relative to each other. We found a substantial stiffening of single filaments above a characteristic transition frequency of 1-30 Hz depending on the filament's molecular composition. Below this frequency, filament elasticity only depends on its contour and persistence length. Interestingly, this elastic behavior is transferable to small networks, where we found the surprising effect that linear two filament connections act as transistor-like, angle dependent momentum filters, whereas triangular networks act as stabilizing elements. These observations implicate that cells can tune mechanical signals by temporal and spatial filtering stronger and more flexibly than expected

Policies for African seed enterprise development

The commercial seed sector has been slow to develop in sub-Saharan Africa. The paper examines the major impediments and identifies areas in which seed policies can be strengthened. Seed enterprise development has been hampered by regulatory frameworks that favor parastatal enterprises and that inhibit commercial innovation. In addition, government and donor projects provide large amounts of free or subsidized seed that further discourages seed enterprise development. In addition to regulatory reform and the curtailment of many seed distribution projects, there are other policy changes that need to be implemented. National agricultural research institutes need to invest more resources in promoting their varieties and helping to stimulate commercial seed production. Greater emphasis is required on regional strategies for public plant breeding and private seed marketing. National policies need to strengthen input marketing capacity and infrastructure. Finally, donors, governments and NGOs should shift from trying to encourage village-level commercial seed production and instead strengthen farmers’ capacities to assess new varieties and to be effective consumers of commercial input