Flight, Wind Tunnel, and Numerical Experiments with a Slender Cone at Incidence

The three-dimensional leeward separation about a 5-deg semi-angle cone of 11 deg angle of incidence was Investigated in night, in the wind tunnel, and by numerical computations. The test conditions were Mach numbers of 0.6, 1.5, and 1.8 at Reynolds numbers between 7 and 10 million based on freestream conditions and a 76.2-cm (30-in.) length of surface. The surface pressure conditions measured included those of fluctuating and mean static, as well as recovery pressures generated by obstacle blocks to provide skin friction and separation-line locations. The mean static pressures from flight and wind tunnel were in reasonably good agreement. The computed results gave the same distributions, but were slightly more positive in magnitude. The experimentally measured primary and secondary separation line locations compared closely with computed results. There were substantial differences In level between the surface root-mean-square pressure fluctuations obtained in night and in the wind tunnel, due, It Is thought, to a relatively high acoustic disturbance level in the tunnel compared with the quiescent atmospheric conditions in night

Communications Biophysics

Contains reports on two research projects

Bio-inspired canopies for the reduction of roughness noise

This work takes inspiration from the structure of the down covering the flight feathers of larger species of owls, which contributes to their ability to fly almost silently at frequencies above 1.6 kHz. Microscope photographs of the down show that it consists of hairs that form a structure similar to that of a forest. The hairs initially rise almost perpendicular to the feather surface but then bend over in the flow direction to form a canopy with an open area ratio of about 70 percent. Experiments have been performed to examine the noise radiated by a large open area ratio canopy suspended above a surface. The canopy is found to dramatically reduce pressure fluctuations on the underlying surface. While the canopy can produce its own sound, particularly at high frequencies, the reduction in surface pressure fluctuations can reduce the noise scattered from an underlying rough surface at lower frequencies. A theoretical model is developed which characterizes the mechanism of surface pressure reduction as a result of the mixing layer instability of flow over forest canopies.Office of Naval Research (Grant IDs: N00014-13-1-0244, N00014-14-1-0242

A study of the social and physical environment in catering kitchens and the role of the chef in promoting positive health and safety behaviour

This is the account of a mixed method study of chefs and their kitchens in order to identify the nature of their workplace and how this affects their ability to manage health and safety in the kitchen. It included extended periods of observation, monitoring of physical parameters, analysis of records of reported accidents, and a series of reflexive interviews. The findings were integrated and then fed back in a smaller number of second interviews in order to test whether the findings fitted in with the chefs' understanding of their world. Major factors identified included survival in a market environment, the status of the chef (and the kitchen) within organisations, marked autocracy of chefs, and an increasing tempo building up to service time with commensurate heat, noise, and activity. In particular during the crescendo, a threshold shift in risk tolerance was identified. The factors, their interplay, and their implications for health and safety in the catering kitchen are discussed

An unusual cause of severe metabolic acidosis ; in reply

The document attached has been archived with permission from the editor of the Medical Journal of Australia. An external link to the publisher’s copy is included. See page 4 of PDF for this item.John V Peters, Natasha Rogers and Sandra L Peak

Presidential influence over the systemic agenda

Abstract One of the most widely accepted sources of presidential power is agenda setting. Being able to affect the media's agenda on key issues-influencing the systemic agenda and "expanding the scope of conflict"-has enormous consequences for the president's ability to govern effectively. Yet the literature to date has not conclusively determined the extent to which presidents consistently set agendas, especially over the media, because it has not explicitly considered variation in agenda-setting influence by policy type. For these reasons, we test whether presidential public statements have increased the media's attention to three policy areas. Using Vector Autoregression (VAR) analysis, we demonstrate that presidents have some influence over the systemic agenda, at least in the short term, with policy type being an important predictor of presidential influence. Understanding when and why presidents may or may not be successful agenda setters is crucial to explaining the varying legislative impacts of presidential speech making. Agenda setting has long been viewed as a vital source of power in American politics. Whoever controls the agenda affects which issues are debated, how they are framed, and who may participate. Much work on agenda setting holds unequivocally that presidents have this power, and that they are uniquely situated to affect the national agenda. John Kingdon (1984, 25), in his seminal study on Washington agenda setting, maintained that "no other single actor in the political system has quite the capability of the president to set agendas." Baumgartner and Jones (1993, 241) surmised, "no single actor can focus attention as clearly, or change the motivations of such a great number of other actors, as the president." After all, these scholars assert that Congress, the public, and the news media regularly look to presidents for leadership on the nation's most pressing issues. Presidential influence over agenda setting arguably increases the president's ability to govern effectively. If the president dictates the issues that Congress debates each legislative session, he is more likely to succeed on his top legislative prioritie

Communications Biophysics

Contains reports on three research projects.United States Air Force (Contract AF19(602)-4112

Where Does Blood Flow Restriction Fit in the Toolbox of Athletic Development? A Narrative Review of the Proposed Mechanisms and Potential Applications

Blood flow-restricted exercise is currently used as a low-intensity time-efficient approach to reap many of the benefits of typical high-intensity training. Evidence continues to lend support to the notion that even highly trained individuals, such as athletes, still benefit from this mode of training. Both resistance and endurance exercise may be combined with blood flow restriction to provide a spectrum of adaptations in skeletal muscle, spanning from myofibrillar to mitochondrial adjustments. Such diverse adaptations would benefit both muscular strength and endurance qualities concurrently, which are demanded in athletic performance, most notably in team sports. Moreover, recent work indicates that when traditional high-load resistance training is supplemented with low-load, blood flow-restricted exercise, either in the same session or as a separate training block in a periodised programme, a synergistic and complementary effect on training adaptations may occur. Transient reductions in mechanical loading of tissues afforded by low-load, blood flow-restricted exercise may also serve a purpose during de-loading, tapering or rehabilitation of musculoskeletal injury. This narrative review aims to expand on the current scientific and practical understanding of how blood flow restriction methods may be applied by coaches and practitioners to enhance current athletic development models.publishedVersionPaid open acces