Flight and tunnel test results of the MDC mechanical jet noise suppressor nozzle

The flight and wind tunnel tests to determine the acoustic and performance effects of a mechanical jet noise suppressor nozzle mounted on a Viper engine of an HS-125 airplane are discussed. Flyover noise measurements were made with microphones mounted on top of a 137.5 m bridge tower. Seven nozzle configurations including two references nozzles, two suppressors, and three ejector inlets were tested. The suppressor nozzle of interest for an advanced supersonic transport, the suppressor/treated ejector, achieved a measured noise reduction of 14 EPNdB relative to a conventional conical reference nozzle at the highest pressure ratio tested (approximately 2.5). The unique engine nacelle, flight hardware, and nacelles from the HS-125 flight test program, combined with a simulated HS-125 fuselage were windtunnel tested. Both propulsion and acoustic data were recorded. Preliminary thrust data results from the wind tunnel tests are summarized and compared to other mechanical suppressor test results. The test results indicate that a noise reduction of at least 16 EPNdB would be possible for the suppressor/ejector nozzle scaled to typical AST engine size with a 5% thrust loss at a typical takeoff climb speed

Magnetically asymmetric interfaces in a (LaMnO3_3)/(SrMnO3_3) superlattice due to structural asymmetries

Polarized neutron reflectivity measurements of a ferromagnetic [(LaMnO$_3$)$_{11.8}$/(SrMnO$_3$)$_{4.4}$]$_6$ superlattice reveal a modulated magnetic structure with an enhanced magnetization at the interfaces where LaMnO$_3$ was deposited on SrMnO$_3$ (LMO/SMO). However, the opposite interfaces (SMO/LMO) are found to have a reduced ferromagnetic moment. The magnetic asymmetry arises from the difference in lateral structural roughness of the two interfaces observed via electron microscopy, with strong ferromagnetism present at the interfaces that are atomically smooth over tens of nanometers. This result demonstrates that atomic-scale roughness can destabilize interfacial phases in complex oxide heterostructures.Comment: 5 pages, 4 figure

The Use of Humor in Intercollegiate Varsity Sport

Three separate studies examined the use of humor in intercollegiate varsity sport. The first explored, via focus groups, who, what, where, when, and why humor is used. The second examined, via multilevel modeling, how athletes’ perceptions of cohesion (measured via the Group Environment Questionnaire; Carron et al., 1985) related to the styles of humor (measured via a modified version of the Martin et al. (2003) Humor Styles Questionnaire), used by athletes, teams, and head coaches. The third investigated, via multilevel modeling, how the styles of humor used by athletes and head coaches related to athletes’ liking of the head coach, via select items from the Coach Evaluation Questionnaire (Rushall & Wiznak, 1985). Results showed that humor use was ubiquitous and associated with positive and negative outcomes. The results of Study 1 showed that humor was used to achieve the positive outcomes of enhanced sport relationships, coping, and performance. Within sport relationships, the results from Study 2 and 3 showed that athletes’ and coaches’ use of positive styles of humor (i.e., affiliative and self-enhancing) were generally related to athletes’ increased perceptions of team cohesion and liking of the head coach. With regard to negative outcomes, the results of Study 1 showed that if humor use was excessive, ill-timed, and/or negative (i.e. aggressive or self-defeating), it could result in damaged relationships, distressed individuals, and reduced performance. Studies 2 and 3 also showed that athletes’ use of self-defeating humor was associated with decreased athlete perceptions of task cohesion and liking of the head coach, whereas head coaches’ use of self-defeating humor was associated with decreased athlete perceptions of social cohesion. These results align with Martin’s (2007) conceptualization of humor as a social skill such that its use, when in the right amount, at an ideal time, and with the optimal style, can have numerous potential benefits. This dissertation was also the first to note potential detrimental outcomes associated with the use of humor in intercollegiate varsity sport; thus several recommendations for both coaches and athletes were advanced to maximize the benefits of its use

Suppressed magnetization in La0.7_{0.7}Ca0.3_{0.3}MnO3_3/YBa2_2Cu3_3O7−δ_{7-\delta} superlattices

We studied the magnetic properties of La$_{0.7}$Ca$_{0.3}$MnO$_3$ / YBa$_2$Cu$_3$O$_{7-\delta}$ superlattices. Magnetometry showed that with increasing YBa$_2$Cu$_3$O$_{7-\delta}$ layer thickness the saturation magnetization per La$_{0.7}$Ca$_{0.3}$MnO$_3$ layer decreases. From polarized neutron reflectometry we determined that this magnetization reduction is due to an inhomogenous magnetization depth profile arising from the suppression of magnetization near the La$_{0.7}$Ca$_{0.3}$MnO$_3$ / YBa$_2$Cu$_3$O$_{7-\delta}$ interface. Electron energy loss spectroscopy indicates an increased 3d band occupation of the Mn atoms in the La$_{0.7}$Ca$_{0.3}$MnO$_3$ layers at the interface. Thus, the suppression of ferromagnetic order at the La$_{0.7}$Ca$_{0.3}$MnO$_3$ / YBa$_2$Cu$_3$O$_{7-\delta}$ interface is most likely due to charge transfer between the two materials.Comment: 4 pages, 4 figures, submitted to Phys. Rev.

Magnetic Structure in Fe/Sm-Co Exchange Spring Bilayers with Intermixed Interfaces

The depth profile of the intrinsic magnetic properties in an Fe/Sm-Co bilayer fabricated under nearly optimal spring-magnet conditions was determined by complementary studies of polarized neutron reflectometry and micromagnetic simulations. We found that at the Fe/Sm-Co interface the magnetic properties change gradually at the length scale of 8 nm. In this intermixed interfacial region, the saturation magnetization and magnetic anisotropy are lower and the exchange stiffness is higher than values estimated from the model based on a mixture of Fe and Sm-Co phases. Therefore, the intermixed interface yields superior exchange coupling between the Fe and Sm-Co layers, but at the cost of average magnetization.Comment: 16 pages, 6 figures and 1 tabl

On the full scale and model scale cavitation comparisons of a Deep-V catamaran research vessel

In pushing for greener ships and more sustainable operations, designers and researchers are being challenged to increase vessel performance whilst reducing environmental impact. One topical, and a somewhat challenging aspect of this pursuit, is the reduction in Underwater Radiated Noise (URN). There are several European Collaborative Research Projects currently underway that aim to outline a framework for noise standards, amongst these projects is the Seventh Framework Project (FP7) “Suppression of Underwater Noise Induced by Cavitation” (SONIC) that has been tasked with concentrating on the URN from propeller cavitation; the main contributor to underwater noise generation. As one of the participants of the SONIC project the Newcastle University was involved in the full-scale trials and model-scale propeller testing campaign. The full-scale trial conducted on board Newcastle University’s catamaran research vessel R/V The Princess Royal involved cavitation observations though the dedicated observation windows above each propeller, Propeller Excited Vibration measurements as well as the off-board URN measurements. The model scale tests were made in The Emerson Cavitation Tunnel using a 1:3.5 scale dummy model of the starboard side demi-hull of the vessel. These tests tried to emulate, as best as possible, the full-scale trials in terms of measurement locations and viewing angles

UpLIFTIng PFI: does LIFT improve public-private procurement?

The Private Finance Initiative (PFI) and Local Improvement Finance Trust (LIFT) were both introduced by the UK government as part of a drive to improve public service provision. Both PFI and LIFT focus on leveraging the key strengths of the public and private sectors when developing new facilities. This paper does not seek to question the need for new infrastructure, but rather discusses the difficulties encountered when trying to analyse LIFT as a system and when evaluating whether it can address earlier concerns about the PFI procurement process. Our analysis suggests that it is difficult to predict whether LIFT will be capable of delivering on its promise of providing cost-effective, bespoke Primary Care facilities