Comparison of wind tunnel and flight test afterbody and nozzle pressures for a twin-jet fighter aircraft at transonic speeds

Afterbody and nozzle pressures measured on a 1/12-scale model and in flight on a twin-jet fighter aircraft were compared as Mach number varied from 0.6 to 1.2, Reynolds number from 17.5 million to 302.5 million, and angle of attack from 1 to 7 deg. At Mach 0.6 and 0.8, nozzle pressure coefficient distributions and nozzle axial force coefficients agreed and showed good recompression. At Mach 0.9 and 1.2, flow complexity caused a loss in recompression for both flight and wind tunnel nozzle data. The flight data exhibited less negative values of pressure coefficient and lower axial force coefficients than did the wind tunnel data. Reynolds number effects were noted only at these Mach numbers. Jet temperature and mass flux ratio did not affect the comparisons of nozzle axial flow coefficient. At subsonic speeds, the levels of pressure coefficient distributions on the upper fuselage and lower nacelle surfaces for flight were less negative than those for the model. The model boundary layer thickness at the aft rake station exceeded that for the forward rake station and increased with increasing angle of attack. The flight boundary layer thickness at the aft rake station was less than that for the forward rake station and decreased with increasing angle of attack

Estimating the Supply Curve for Nutria Pelts From Coastal Louisiana and the Impacts Associated with Declining Prices

Nutria harvests vary with price. As pelt prices declined, nutria populations - and wetland degradation have risen. This paper develops a nutria supply model to predict harvests at various prices which are incorporated into a wetland loss model to determine how alternative incentive programs affect changes in wetland degradation.Resource /Energy Economics and Policy,

THE ROLE OF INFORMATION TECHNOLOGY IN ORGANIZATION DESIGN

This paper introduces a set of information technology variables which can be used in designing organizations. We first look at traditional design variables and then present a series of options enabled by modern information technology. We use these IT design variables to describe four prototypical organizations which are beginning to appear in the workplace: virtual, negotiated, traditional and vertically integrated. It is argued that an organization designer must also consider how structure and technology influence job tasks and people in order to be successful. The paper discusses potential implementation difficulties, particularly in motivating traditional organizations to take advantage of IT design variables. The paper concludes that the design of information technology and the design of organizations is largely becoming the same task.Information Systems Working Papers Serie

A Pedagogical Exercise in Concept Integration: Or Relaxing Assumptions and Moving Toward the Real World

This article suggests to the educator an example of combining conceptual notions that should be familiar to students of business. In addition the example, which combines the notions of economic lot size and the learning curve, serves as a means for dealing with those critical of the many assumptions that often precede model building. This exercise or ones similar to it should give critics and/or students some appreciation of the complexities which are unveiled as we attempt to model closer to real-world applications

Combining the Learning Curve Concept with Economic Lot Sizing

Simple concepts familiar to most operations management students are frequently not integrated as a result of the complexity generated by their combination. This expository note demonstrates a method for combining the economic lot size concept with the learning curve and using a simple computer algorithm for solution purposes. It avoids the traditional trade-off of reality and accuracy for expediency

Serologic Evidence of \u3cem\u3eBrucella\u3c/em\u3e and Pseudorabies in Mississippi Feral Swine

Feral swine (Sus scrofa) are an ever-increasing problem across the United States. Besides physical environmental damage that they cause, they may harbor and transmit a number of pathogens to humans, livestock, and other domestic animals. We sampled feral swine across the state of Mississippi for titers to several diseases. Antibodies against Brucella were found in 16 of 499 (3.2%) feral swine, and antibodies against pseudorabies (porcine herpes virus, type 1; Herpesveridae sp.) virus were identified in 37 of 499 (7.4%) feral swine from across the state of Mississippi. Evidence of classical swine fever, African swine fever, swine influenza, and foot-and-mouth disease were not identified in any of the feral swine examined