Interior noise levels of two propeller-driven light aircraft

The relationships between aircraft operating conditions and interior noise and the degree to which ground testing can be used in lieu of flight testing for performing interior noise research were studied. The results show that the noise inside light aircraft is strongly influenced by the rotational speed of the engine and propeller. Both the overall noise and low frequency spectra levels were observed to decrease with increasing high speed rpm operations during flight. This phenomenon and its significance is not presently understood. Comparison of spectra obtained in flight with spectra obtained on the ground suggests that identification of frequency components and relative amplitude of propeller and engine noise sources may be evaluated on stationary aircraft

Experimental forced vibration responses of test houses during the Edwards Air Force Base phase of the national sonic boom test program

Experimental vibration studies were conducted on two houses to determine some of the dynamic response characteristics, resulting from sonic boom. The primary objectives of the vibration tests were to identify the mode shapes associated with the various frequencies determined from the sonic boom response data, and to obtain some basic information about the vibration behavior of buildings in general. The results are presented of forced sinusoidal vibration studies of some components of the test structures. Included are acceleration response data on selected walls, wall surface modal patterns, and vibration induced noise measurements at various locations in the test structures

Review of subjective measures of human response to aircraft noise

The development of aircraft noise rating scales and indexes is reviewed up to the present time. Single event scales, multiple event indexes, and their interrelation with each other, are considered. Research requirements for further refinement and development of aircraft noise rating quantification factors are discussed

Description of Langley low-frequency noise facility and study of human response to noise frequencies below 50 cps

Test facility for determining human performance in very low frequency noise environment - physiological and psychological response

Description and research capabilities of the Langley Low Frequency Noise Facility

Description and research capabilities of low frequency noise facilit

Representation of Dormant and Active Microbial Dynamics for Ecosystem Modeling

Dormancy is an essential strategy for microorganisms to cope with environmental stress. However, global ecosystem models typically ignore microbial dormancy, resulting in major model uncertainties. To facilitate the consideration of dormancy in these large-scale models, we propose a new microbial physiology component that works for a wide range of substrate availabilities. This new model is based on microbial physiological states and is majorly parameterized with the maximum specific growth and maintenance rates of active microbes and the ratio of dormant to active maintenance rates. A major improvement of our model over extant models is that it can explain the low active microbial fractions commonly observed in undisturbed soils. Our new model shows that the exponentially-increasing respiration from substrate-induced respiration experiments can only be used to determine the maximum specific growth rate and initial active microbial biomass, while the respiration data representing both exponentially-increasing and non-exponentially-increasing phases can robustly determine a range of key parameters including the initial total live biomass, initial active fraction, the maximum specific growth and maintenance rates, and the half-saturation constant. Our new model can be incorporated into existing ecosystem models to account for dormancy in microbially-mediated processes and to provide improved estimates of microbial activities.Comment: 38 pages, 2 Tables, 4 Figure

Effects of aircraft noise on flight and ground structures

Acoustic loads measured on jet-powered STOL configurations are presented for externally blown and upper surface blown flap models ranging in size from a small laboratory model up to a full-scale aircraft model. The implications of the measured loads for potential acoustic fatigue and cabin noise are discussed. Noise transmission characteristics of light aircraft structures are presented. The relative importance of noise transmission paths, such as fuselage sidewall and primary structure, is estimated. Acceleration responses of a historic building and a residential home are presented for flyover noise from subsonic and supersonic aircraft. Possible effects on occupant comfort are assessed. The results from these three examples show that aircraft noise can induce structural responses that are large enough to require consideration in the design or operation of the aircraft

Exact 1-D Model for Coherent Synchrotron Radiation with Shielding and Bunch Compression

Coherent Synchrotron Radiation has been studied effectively using a 1-dimensional model for the charge distribution in the realm of small angle approximations and high energies. Here we use Jefimenko's form of Maxwell's equations, without such approximations, to calculate the exact wake-fields due to this effect in multiple bends and drifts. It has been shown before that the influence of a drift can propagate well into a subsequent bend. We show, for reasonable parameters, that the influence of a previous bend can also propagate well into a subsequent bend, and that this is especially important at the beginning of a bend. Shielding by conducting parallel plates is simulated using the image charge method. We extend the formalism to situations with compressing and decompressing distributions, and conclude that simpler approximations to bunch compression usually overestimates the effect. Additionally, an exact formula for the coherent power radiated by a Gaussian bunch is derived by considering the coherent synchrotron radiation spectrum, and is used to check the accuracy of wake-field calculations

Clarifying the costs of conflicts of interest

Over the past two decades, a deep suspicion has emerged in the healthcare community about the influence of private industry – particularly the pharmaceutical industry – over doctors, researchers, regulators and policymakers [1, 2]. In response to the perceived threats posed by conflicts of interest (COI), there have been calls for a range of measures including stricter disclosure statements, more transparency, and tighter regulation of medical and industry interactions [3]. Not surprisingly, such demands tend to be resisted by the pharmaceutical industry, and by a subset of clinicians and researchers who believe that claims of adverse industry influence are overblown [4]. One such example is the recent article by Barton, Stossel and Stell in the International Journal of Clinical Practice [5]. Barton et al. argue that concerns about COI are exaggerated and unsupported by empirical evidence, and that demands for regulation and transparency distract medical professionals, researchers and policymakers from their primary task – improving patient outcomes. Furthermore, they suggest that if there is no evidence that patient outcomes are negatively affected by COI, then there is no cause for concern. They claim that the ‘conflict of interest movement has failed to substantiate its central claim that interactions between physicians, researchers and the medical products industry cause physicians to make clinical decisions that are adverse to the best interests of their patients.’ The medical community and bioethicists in particular, should therefore stop worrying about COI.NHMRC Project Grant (APP1059732

Students face deep conflict in reporting harassment

Coopes describes steps to change the culture of bullying and harassment in Australia’s medical profession.1 We applaud the Royal Australasian College of Surgeons for its action plan to tackle such harassment,2 but the problem goes much deeper than surgeons behaving badly. In 2015 we conducted a study in New South Wales about conflicts of interest in medicine. Participants were medical students, medical educators, and other clinicians. Students and junior doctors felt conflicted between reporting others’ inappropriate behaviour and protecting their own jobs or opportunities. These behaviours included bullying and harassment,1 as well as corner cutting that compromised patient safety. In both scenarios participants admitted that they would be unlikely to report a senior colleague. This reluctance stemmed from a deep conflict: students are taught that their responsibility is to patients, but they know that reporting a more senior doctor is very likely to harm their career. We suggest that the hierarchy of Australia’s medical training means that the “silent bystanding” that Coopes mentions is entrenched from the outset of medical education. Culture change needs to recognise that students are currently made acutely aware of existing hierarchies and their vulnerable career positions from their first years of medicine. It also needs to tackle the gender imbalance in senior roles. Numbers of female medical graduates have been similar to or greater than those of male students since 1994 in Australia,3 but, more than 20 years later, representation of women in senior medical roles remains very low. The burden for change cannot rest solely on female doctors and students. This kind of culture change requires strong political commitment from senior male allies, who benefit from the current system, and solidarity from male medical students, who are likely to occupy senior positions in the future