Reduction of JT8D powered aircraft noise by engine refanning

The technical feasibility is described of substantially reducing the noise levels of existing JT8D powered aircraft by retrofitting the existing fleet with quieter refan engines and new acoustically treated nacelles. No major technical problems exist that preclude the development and installation of refanned engines on aircraft currently powered by the JT8D engine. The refan concept is technically feasible and provides calculated noise reductions of from 7 to 8 EPNdb for the B727-200 aircraft and from 10 to 12 EPNdb for the DC-9-32 aircraft at the FAR Part 36 measuring stations. These noise levels are lower than both the FAR Part 36 noise standards and the noise levels of the wide-body DC-10-10. Corresponding reductions in the 90 EPNdb footprint area are estimated to vary from about 70 percent for the DC-9 to about 80 percent for the B727

Introduction: A handbook on territorial impact assessment (TIA)

Territorial Impact Assessment (TIA) is a relatively ‘new kid on the block’ of policy evaluation. Resting upon the holistic notion of territory, which encompasses multiple analytic dimensions (economy, society, environment, governance, spatial planning), TIA is the most complex, yet with the policy evaluation procedure with the largest potential to assess projects, programmes and policies. Indeed, policy evaluation procedures are now deeply rooted in sub-national, national and transnational territorial development strategies and processes. However, unlike the plethora of published books on Environmental Impact Assessment (EIA) and other Impact Assessment (IA) methodologies, presently no TIA handbook has been published by any major international publisher. As such, this one intends to add a substantial contribution to available literature by presenting to the interested reader the most relevant TIA methodologies that have been produced so far. Furthermore, all the chapters, written by the authors of each TIA methodology presented, provide a detailed, updated and scientifically accurate explanation of their particular purpose and methodological operation. In the end, the reader is presented with a complete set of TIA methodologies to select from based on their advantages/disadvantages for a particular case-study. For a better understanding of how all the presented TIA methodologies work, concrete examples are presented in each chapter.info:eu-repo/semantics/acceptedVersio

Effect of Various Blade Modifications on Performance of A16-Stage Axial-Flow Compressor. V - Effect on Over-All Performance Characteristics of a 20-Percent Reduction in Solidity of the Fourteenth Through Sixteenth Stage Rotors

The performance of a 16-stage axial-flow compressor, in which the mean-radius solidity was reduced from 1.28 to 1.02 in the fourteenth through sixteenth stage rotors was determined. The performance of this modification was compared with that of the compressor with original rotors. The reduced solidity resulted in slightly improved performance

Dualization of non-Abelian BF model

We show that dualization of BF models to Stueckelberg-like massive gauge theories allows a non-Abelian extension. We obtain local Lagrangians which are straightforward extensions of the Abelian results.Comment: 6 pages, ReVTeX, no figures, to be publ. on Phys.Lett.

Effect of Various Blade Modifications on Performance of a 16-Stage Axial-Flow Compressor. III - Effect on Over-All Performance Characteristics on Increasing Stator-Blade Angles in Inlet Stages

The stator-blade angles in the first four stages of a 16-stage axial-flow compressor were increased in order to decrease the angles of attack of these stages, and thereby to improve part-speed performance. The performance of this modified compressor was compared with that of the same compressor with original blade angles