Laser diagnostics for microgravity droplet studies

Rapid advances have recently been made in numerical simulation of droplet combustion under microgravity conditions, while experimental capabilities remain relatively primitive. Calculations can now provide detailed information on mass and energy transport, complex gas-phase chemistry, multi-component molecular diffusion, surface evaporation and heterogeneous reaction, which provides a clearer picture of both quasi-steady as well as dynamic behavior of droplet combustion. Experiments concerning these phenomena typically result in pictures of the burning droplets, and the data therefrom describe droplet surface regression along with flame and soot shell position. With much more precise, detailed, experimental diagnostics, significant gains could be made on the dynamics and flame structural changes which occur during droplet combustion. Since microgravity experiments become increasingly more expensive as they progress from drop towers and flights to spaceborne experiments, there is a great need to maximize the information content from these experiments. Sophisticated measurements using laser diagnostics on individual droplets and combustion phenomena are now possible. These include measuring flow patterns and temperature fields within droplets, vaporization rates and vaporization enhancement, radical species profiling in flames and gas-phase flow-tagging velocimetry. Although these measurements are sophisticated, they have undergone maturation to the degree where with some development, they are applicable to studies of microgravity droplet combustion. This program beginning in September of 1992, will include a series of measurements in the NASA Learjet, KC-135 and Drop Tower facilities for investigating the range of applicability of these diagnostics while generating and providing fundamental data to ongoing NASA research programs in this area. This program is being conducted in collaboration with other microgravity investigators and is aimed toward supplementing their experimental efforts

Agricultural Tenure in England and Wales 2007

The report presents a repeat of a 1989-90 postal survey to explore the land tenurial changes in England and Wales that have resulted from legislative and structural change. Clearly, since 1990, the introduction of Farm Business Tenancies means that the two sets of results, while not directly comparable, allows the occupancy of land under unconventional forms of tenancy to be explored and contrasted. Furthermore, many factors influence the occupancy of land including taxation, inheritance laws, the profitability of farming, and structural and policy changes within the industry. Therefore, the occupancy of agricultural land in 2007 should be set against this backcloth of socio-political changes that impact upon the industry. Finally, this report is split into two sections, the first focuses on the occupation of land in England and Wales using weighted sample data, while the second explores some of the dynamics behind land tenure using the unweighted sample data.Land Tenure, Farm Business Tenancies, Agricultural Occupancy, Informal Tenure Agreements, Agricultural and Food Policy, Farm Management, Land Economics/Use,

The political geography of EU agricultural policy adjustment

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