Optimum Repair Level Analysis (ORLA) for the Space Transportation System (STS)

A repair level analysis method applied to a space shuttle scenario is presented. A determination of the most cost effective level of repair for reparable hardware, the location for the repair, and a system which will accrue minimum total support costs within operational and technical constraints over the system design are defined. The method includes cost equations for comparison of selected costs to completion for assumed repair alternates

The minimum free-stream wind speed for initiating motion of surface material on Mars

Estimates of the minimum free-stream wind speed that is required for initiating the motion of surficial material on Mars have ranged from 30 to about 200 meters per second. Thus the best value for this quantity is not well established. Graphical comparison of much of the pertinent data taken in the laboratory and in the field on Earth provides a minimum value for the Bagnold coefficient of 0.08 and this in turn provides a minimum value for the threshold friction velocity of 1.3 meters per second for initiating motion of particulate matter on Mars at low elevations where the pressure is 7 millibars. The most appropriate value of the ratio of friction velocity to free-stream velocity for putative unstable condition appears to be 0.026. Thus the minimum free-stream wind speed for initiating motion is obtained as 50 meters per second. If the surface material on Mars, however, is less cohesive than that on earth, the minimum value may be smaller

Flight tests of a direct lift control system during approach and landing

Flight tests of modified aileron direct lift control system during approach and landing of F8-C aircraf

The application of low crude protein wheat-soyabean diets to growing and finishing pigs: 2. The effects on nutrient digestibility, nitrogen excretion, faecal volatile fatty acid concentration and ammonia emission from boars

peer-reviewedThis study received financial support from Telltech Ltd. (Wicklow, Ireland) and Enterprise Ireland (Dublin, Ireland).Diets containing 132, 152, 183 and 206 g/kg crude protein (CP) were fed to growing and finishing boars to evaluate the effect on nutrient digestibility, N balance, faecal volatile fatty acids (VFA) and ammonia-N (NH3–N) emission. Dietary CP concentration was adjusted by altering the ratio of wheat:soyabean meal. Lysine, threonine, tryptophan and total sulphur-containing amino acids were included in all diets at concentrations equivalent to that in the highest CP diet. All diets were formulated to provide 9.7 MJ/kg of net energy. Urine and faeces were collected from 16 boars (4 boars per treatment) housed in metabolism crates. Collections were performed at 72, 80 and 87 kg live weight. NH3–N emission was measured over 10 days using a laboratory scale procedure. Reducing the concentration of dietary CP decreased N intake (linear, P < 0.01), the excretion of urinary N, ammoniacal N and total N (linear, P < 0.001; cubic, P < 0.001) and the emission of NH3–N (linear, P < 0.001; cubic, P < 0.01). Total N excretion and NH3–N emission decreased 8.7% and 10.1% per 10 g/kg reduction in dietary CP concentration between 205.6 and 131.9 g/kg, respectively. There was no interaction between dietary CP concentration and collection period. N balance differed between the collection periods and less NH3–N was emitted at 87 kg than at 72 kg. Decreasing dietary CP reduced faecal VFA concentration (linear, P < 0.05) and the molar proportions of acetic and butyric acids (quadratic, P < 0.01).Enterprise Irelan

Schwarzchild Black Holes in Matrix Theory II

We present a crude Matrix Theory model for Schwarzchild black holes in uncompactified dimension greater than $5$. The model accounts for the size, entropy, and long range state interactions of black holes. The key feature of the model is a Boltzmann gas of D0 branes, a concept which depends on certain qualitative features of Matrix Theory which have not previously been utilized in studies of black holes.Comment: 20 pages,harvmac,big, Some Typos corrected, 1 reference adde

Old model, new problem: when should you update a model and what happens when you do?

This paper is a summary of some of the considerations involved in applying an existing model to a new problem, in particular in deciding whether to update or not, and some of the issues involved in interpreting the output from the new application. Thus where you start from does influence where you end up. Both change in total surplus and to a lesser extent the distribution of this change in total surplus across sectors, depends on the price and quantity data which is used to define the initial equilibrium, even if elasticity values are the same. So careful consideration should be given to whether an existing model should be updated because updating a model does matter. The final point to restate is that consumers of pig meat end up being the winners from either cost saving technology at the farm level or new product development or advertising campaigns at the retail level. Even for new technology implemented at the farm level, producers only receive about 20 per cent of the total benefits. These issues are discussed in detail in Mounter et al. (2005a, 2005b). Therefore in relation to the new problem outlined above, we now have a modelling framework available for the task that has been tested in a number of different ways and that now reflects current industry structure and size. It should be a more appropriate framework than the original that was described in the papers by Mounter et al. (2004, 2005a, 2005b).new model, old model, decision making, change in total surplus, updating a model, new technologies, pork, industry structure, industry size, Agribusiness, Agricultural Finance, Environmental Economics and Policy, Farm Management, Industrial Organization, Institutional and Behavioral Economics, Livestock Production/Industries, Marketing,