Coupled aerodynamic and acoustical predictions for turboprops

To predict the noise fields for proposed turboprop airplanes, an existing turboprop noise code by Farassat has been modified to accept blade pressure inputs from a three-dimensional aerodynamic code. A Euler-type code can handle the nonlinear transonic flow of these high-speed, highly swept blades. This turbofan code was modified to allow the calculation mesh to extend to about twice the blade radius and to apply circumferential periodicity rather than solid-wall boundary conditions on the blade in the region between the blade tip and the outer shroud. Outputs were added for input to the noise prediction program and for color contour plots of various flow variables. The Farassat input subroutines were modified to read files of blade coordinates and predicted surface pressures. Aerodynamic and acoustic results are shown for the SR-3 model blade. Comparison of the acoustic predicted results with measured data show good agreement

Martian glaciation and the flow of solid CO2

The flow law determined experimentally for solid CO2 establishes that a hypothesis of glacial flow of CO2 at the Martian poles is not physically unrealistic. Compression experiments carried out under 1 atm pressure and constant strain rate demonstrate that the strength of CO2 near its sublimation point is considerably less than the strength of water ice near its melting point. The data fit a power law "creep" equation of the form , where is compressive strain rate (sec-1), [sigma] is compressive stress (bars), R is the gas constant in calories per mole, and T is absolute temperature. The exponent of [sigma] of 3.9 contrasts with a value near 3.1 for water ice, and indicates that the strain rate is somewhat more sensitive to stress for CO2 than for water. Likewise, the low activation energy for creep, 12 200 cal mole-1, illustrates that CO2 is not highly sensitive to temperature and is thus likely to flow over a broad range of temperatures below its melting point. Strength values for CO2 are of the order of one-tenth to one-third the strength of ice under equivalent conditions.A plausible glacial model for the Martian polar caps can be constructed and is helpful in explaining the unique character of the polar regions. CO2-rich layers deposited near the pole would have flowed outward laterally to relieve high internal shear stresses. The topography of the polar caps, the uniform layering of the layered deposits, and the general extent of the polar "sediments" could all be explained using this model. Flow of CO2 rather than water ice greatly reduces the problems with Martian glaciation. Nevertheless, problems do remain, in particular the large amounts of CO2 necessary, the need to increase vapor pressure and temperature with depth in the polar deposits, and the lack of good observational evidence of flor features. Within the limits of the present knowledge of surface conditions of Mars, CO2 glaciation appears to be a realistic alternate working hypothesis for the origin of the polar features.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/21831/1/0000234.pd

Jet Noise Modeling for Suppressed and Unsuppressed Aircraft in Simulated Flight

This document describes the development of further extensions and improvements to the jet noise model developed by Modern Technologies Corporation (MTC) for the National Aeronautics and Space Administration (NASA). The noise component extraction and correlation approach, first used successfully by MTC in developing a noise prediction model for two-dimensional mixer ejector (2DME) nozzles under the High Speed Research (HSR) Program, has been applied to dual-stream nozzles, then extended and improved in earlier tasks under this contract. Under Task 6, the coannular jet noise model was formulated and calibrated with limited scale model data, mainly at high bypass ratio, including a limited-range prediction of the effects of mixing-enhancement nozzle-exit chevrons on jet noise. Under Task 9 this model was extended to a wider range of conditions, particularly those appropriate for a Supersonic Business Jet, with an improvement in simulated flight effects modeling and generalization of the suppressor model. In the present task further comparisons are made over a still wider range of conditions from more test facilities. The model is also further generalized to cover single-stream nozzles of otherwise similar configuration. So the evolution of this prediction/analysis/correlation approach has been in a sense backward, from the complex to the simple; but from this approach a very robust capability is emerging. Also from these studies, some observations emerge relative to theoretical considerations. The purpose of this task is to develop an analytical, semi-empirical jet noise prediction method applicable to takeoff, sideline and approach noise of subsonic and supersonic cruise aircraft over a wide size range. The product of this task is an even more consistent and robust model for the Footprint/Radius (FOOTPR) code than even the Task 9 model. The model is validated for a wider range of cases and statistically quantified for the various reference facilities. The possible role of facility effects will thus be documented. Although the comparisons that can be accomplished within the limited resources of this task are not comprehensive, they provide a broad enough sampling to enable NASA to make an informed decision on how much further effort should be expended on such comparisons. The improved finalized model is incorporated into the FOOTPR code. MTC has also supported the adaptation of this code for incorporation in NASA s Aircraft Noise Prediction Program (ANOPP)

Legitimacy in conflict: concepts, practices, challenges

The study of legitimacy in situations of conflict and peacebuilding has increased in recent years. However, current work on the topic adopts many assumptions, definitions, and understandings from classical legitimacy theory, which centers on the relationship between the nation-state and its citizens. In this introduction, we provide a detailed critical overview of current theories of legitimacy and legitimation and demonstrate why they have only limited applicability in conflict and post-conflict contexts, focusing on the three main areas that the articles included in this special issue examine: audiences for legitimacy, sources of legitimacy, and legitimation. In particular, we show how conflict and post-conflict contexts are marked by the fragmentation and personalization of power; the proliferation and fragmentation of legitimacy audiences; and ambiguity surrounding legitimation strategies

Incentive-based approaches to sustainable fisheries

The failures of traditional target-species management have led many to propose an ecosystem approach to fisheries to promote sustainability. The ecosystem approach is necessary, especially to account for fishery-ecosystem interactions, but by itself is not sufficient to address two important factors contributing to unsustainable fisheries — inappropriate incentives bearing on fishers, and the ineffective governance that frequently exists in commercial, developed fisheries managed primarily by total harvest limits and input-controls. We contend that much greater emphasis must be placed on fisher motivation when managing fisheries. Using evidence from more than a dozen ‘natural experiments’ in commercial fisheries, we argue that incentive-based approaches that better specify community, individual harvest, or territorial rights and also price ecosystem services — coupled with public research, monitoring and effective oversight — promote sustainable fisheries.incentives, sustainability, rights, fisheries management

Incentive-based approaches to sustainable fisheries (now replaced by EEN0508)

Using examples from more than a dozen fisheries, we highlight the failures of ‘command control’ management and show that approaches that empower fishers with the incentives and the mandate to be co-custodians of the marine environment can promote sustainability. Evidence is provided that where harvesters share well-defined management responsibilities over fish, and experience both the pain of overexploitation and the gains from conservation, they are much more likely to protect fish stocks and habitat. The key insight is that to maintain marine ecosystems for present and future generations, fishing incentives must be compatible with long-term goals of sustainability.incentives, sustainability, rights, fisheries management

Differential impact of two risk communications on antipsychotic prescribing to people with dementia in Scotland: segmented regression time series analysis 2001-2011

The two risk communications were associated with reductions in antipsychotic use, in ways which were compatible with marked differences in their content and dissemination. Further research is needed to ensure that the content and dissemination of regulatory risk communications is optimal, and to track their impact on intended and unintended outcomes. Although rates are falling, antipsychotic prescribing in dementia in Scotland remains unacceptably hig

Estimating Residual Solids Volume In Underground Storage Tanks

The Savannah River Site liquid waste system consists of multiple facilities to safely receive and store legacy radioactive waste, treat, and permanently dispose waste. The large underground storage tanks and associated equipment, known as the 'tank farms', include a complex interconnected transfer system which includes underground transfer pipelines and ancillary equipment to direct the flow of waste. The waste in the tanks is present in three forms: supernatant, sludge, and salt. The supernatant is a multi-component aqueous mixture, while sludge is a gel-like substance which consists of insoluble solids and entrapped supernatant. The waste from these tanks is retrieved and treated as sludge or salt. The high level (radioactive) fraction of the waste is vitrified into a glass waste form, while the low-level waste is immobilized in a cementitious grout waste form called saltstone. Once the waste is retrieved and processed, the tanks are closed via removing the bulk of the waste, chemical cleaning, heel removal, stabilizing remaining residuals with tailored grout formulations and severing/sealing external penetrations. The comprehensive liquid waste disposition system, currently managed by Savannah River Remediation, consists of 1) safe storage and retrieval of the waste as it is prepared for permanent disposition; (2) definition of the waste processing techniques utilized to separate the high-level waste fraction/low-level waste fraction; (3) disposition of LLW in saltstone; (4) disposition of the HLW in glass; and (5) closure state of the facilities, including tanks. This paper focuses on determining the effectiveness of waste removal campaigns through monitoring the volume of residual solids in the waste tanks. Volume estimates of the residual solids are performed by creating a map of the residual solids on the waste tank bottom using video and still digital images. The map is then used to calculate the volume of solids remaining in the waste tank. The ability to accurately determine a volume is a function of the quantity and quality of the waste tank images. Currently, mapping is performed remotely with closed circuit video cameras and still photograph cameras due to the hazardous environment. There are two methods that can be used to create a solids volume map. These methods are: liquid transfer mapping / post transfer mapping and final residual solids mapping. The task is performed during a transfer because the liquid level (which is a known value determined by a level measurement device) is used as a landmark to indicate solids accumulation heights. The post transfer method is primarily utilized after the majority of waste has been removed. This method relies on video and still digital images of the waste tank after the liquid transfer is complete to obtain the relative height of solids across a waste tank in relation to known and usable landmarks within the waste tank (cooling coils, column base plates, etc.). In order to accurately monitor solids over time across various cleaning campaigns, and provide a technical basis to support final waste tank closure, a consistent methodology for volume determination has been developed and implemented at SRS