Human response to aircraft noise

The human auditory system and the perception of sound are discussed. The major concentration is on the annnoyance response and methods for relating the physical characteristics of sound to those psychosociological attributes associated with human response. Results selected from the extensive laboratory and field research conducted on human response to aircraft noise over the past several decades are presented along with discussions of the methodology commonly used in conducting that research. Finally, some of the more common criteria, regulations, and recommended practices for the control or limitation of aircraft noise are examined in light of the research findings on human response

Health impacts of wind turbines

This report presents the results of a rapid, desk based analysis of peer reviewed UK and international literature from the last four years on the effects of wind turbines on human health. The review covers literature specified by the Scottish government, peer-reviewed original studies and recent peer-reviewed literature reviews. Recent original studies consist mostly of cross-sectional studies and case studies on the effects of wind turbines on local residents. All studies present evidence for annoyance due to wind turbine noise and most concur that there is evidence for sleep disturbance in the presence of wind farms but not necessarily from noise. Both results are in agreement with the effects of noise from other environmental sources. Other health effects are increasingly reported in the presence of wind turbines but the reviewed literature does not provide firm scientific evidence of a causal relationship with wind turbines or even more specifically wind turbine noise. The most widely quoted cross-sectional studies show correlations between annoyance and visual impact, economic benefit and attitude related to wind turbines. Wind turbine sound is reported to be comparatively weakly related to annoyance and inseparable from the other contributing factors. Literature on low frequency noise and infrasound (LFIS) can be categorised as reviews, sound level measurements around windfarms and discussion of mechanisms of perception and response. A Swedish review finds no evidence to support ‘wind turbine syndrome’ while another concludes that further research is required. Regarding noise measurements, there are concerns that a new generation of wind turbines will produce a sound with a spectrum shifted down in frequency. However, a study in Australia concluded that infrasound levels near windfarms were no higher than elsewhere and that higher levels in urban areas were probably due to traffic and other human activity rather than wind turbines. Some other studies found measured sound levels near wind farms to conform with a range of criteria for LFIS. Papers by Salt et al. propose that LFIS may differentially stimulate structures in the human inner ear, and may instigate health effects even when inaudible. The authors seek to build a speculative case utilising experimental data gleaned from guinea pigs and some observations on human experiences with specific pathological conditions. Based upon the documents submitted, the proposal is unproven, and would need clear data from hypothesis driven independent research in humans in order to be credible. A proposal by US consultants that motion sickness-like symptoms reported at one wind farm might be caused by acoustic excitation of the balance organs is not new and has previously been discounted as an explanation for similar reported effects not involving wind turbines. Other evidence on acoustic stimulation of the balance organs has been noted but not reviewed. Health effects from other wind turbine related sources such as shadow flicker have been reported in several studies and guidelines to be less of a problem. Careful wind farm design and operational restrictions are suggested to be sufficient to minimise the impact. The mitigation strategies have been found to vary widely internationally with some countries and federal states using fixed noise limits, others using noise limits relative to existing background levels and many like the UK using a combination of both. Set-back distances are also used internationally but have a number of disadvantages. The relevant UK guideline document ETSU-R-97 aims to provide a reasonable degree of protection to noise sensitive listeners; without unduly restricting the development of wind turbine renewable energy resources. In the international comparison the ETSU-R-97 guidelines tends to result in comparatively low noise limits although direct comparisons between fixed and relative noise limits are difficult. ETSU-R-97 has been criticised for its inconsistent implementation and relative complexity. Good practice guidelines by the Institute of Acoustics which aim to address the implementation issues are due to be published in May

Audio-tactile stimuli to improve health and well-being : a preliminary position paper

From literature and through common experience it is known that stimulation of the tactile (touch) sense or auditory (hearing) sense can be used to improve people's health and well-being. For example, to make people relax, feel better, sleep better or feel comforted. In this position paper we propose the concept of combined auditory-tactile stimulation and argue that it potentially has positive effects on human health and well-being through influencing a user's body and mental state. Such effects have, to date, not yet been fully explored in scientific research. The current relevant state of the art is briefly addressed and its limitations are indicated. Based on this, a vision is presented of how auditory-tactile stimulation could be used in healthcare and various other application domains. Three interesting research challenges in this field are identified: 1) identifying relevant mechanisms of human perception of combined auditory-tactile stimuli; 2) finding methods for automatic conversions between audio and tactile content; 3) using measurement and analysis of human bio-signals and behavior to adapt the stimulation in an optimal way to the user. Ideas and possible routes to address these challenges are presented

Human emotional response to steering wheel vibration in automobiles

This is the post-print (final draft post-refereeing) version of the final published paper that is available from the link below. Copyright @ 2013 Inderscience Enterprises Ltd.This study investigates what form of correlation may exist between measures of the valence and the arousal dimensions of the human emotional response to steering wheel vibration and the vibration intensity metrics obtained by means of the unweighted and the frequency weighted root mean square (rms). A laboratory experiment was performed with 30 participants who were presented 17 acceleration time histories in random order and asked to rate their emotional feelings of valence and arousal using a self-assessment manikin (SAM) scale. The results suggest a highly linear correlation between the unweighted, Wh weighted and Ws weighted vibration intensity metrics and the arousal measures of the human emotional response. The results also suggest that while vibration intensity plays a significant role in eliciting emotional feelings, there are other factors which influence the human emotional response to steering wheel vibration such as the presence of high peaks or high frequency band amplitudes

Facilitating the driver detection of road surface type by selective manipulation of the steering-wheel acceleration signal

Copyright @ 2012 by Institution of Mechanical Engineers.Previous research has investigated the possibility of facilitating the driver detection of road surface type by means of selective manipulation of the steering-wheel acceleration signal. In previous studies a selective increase in acceleration amplitude has been found to facilitate road-surface-type detection, as has selective manipulation of the individual transient events which are present in the signal. The previous research results have been collected into a first guideline for the optimization of the steering-wheel acceleration signal, and the guideline has been tested in the current study. The test stimuli used in the current study were ten steering-wheel acceleration-time histories which were selected from an extensive database of road test measurements performed by the research group. The time histories, which were all from midsized European automobiles and European roads, were selected such that the widest possible operating envelope could be achieved in terms of the r.m.s. value of the steering acceleration, the kurtosis, the power spectral density function, and the number of transient events present in the signal. The time histories were manipulated by means of the mildly non-stationary mission synthesis algorithm in order to increase, by a factor of 2, both the number and the size of the transient events contained within the frequency interval from 20 Hz to 60Hz. The ensemble, composed of both the unmanipulated and the manipulated time histories, was used to perform a laboratory-based detection task with 15 participants, who were presented the individual stimuli in random order. The participants were asked to state, by answering 'yes' or 'no', whether each stimulus was considered to be from the road surface that was displayed in front of them by means of a large photograph on a board. The results suggest that the selectively manipulated steering-wheel acceleration stimuli produced improved detection for eight of the ten road surface types which were tested, with a maximum improvement of 14 per cent in the case of the broken road surface. The selective manipulation did lead, however, to some degradation in detection for the motorway road stimulus and for the noise road stimulus, thus suggesting that the current guideline is not universally optimal for all road surfaces

A stable and accurate control-volume technique based on integrated radial basis function networks for fluid-flow problems

Radial basis function networks (RBFNs) have been widely used in solving partial differential equations as they are able to provide fast convergence. Integrated RBFNs have the ability to avoid the problem of reduced convergence-rate caused by differentiation. This paper is concerned with the use of integrated RBFNs in the context of control-volume discretisations for the simulation of fluid-flow problems. Special attention is given to (i) the development of a stable high-order upwind scheme for the convection term and (ii) the development of a local high-order approximation scheme for the diffusion term. Benchmark problems including the lid-driven triangular-cavity flow are employed to validate the present technique. Accurate results at high values of the Reynolds number are obtained using relatively-coarse grids

Social-ecological soundscapes: examining aircraft-harvester-caribou conflict in Arctic Alaska

Thesis (M.S.) University of Alaska Fairbanks, 2017As human development expands across the Arctic, it is crucial to carefully assess the impacts to remote natural ecosystems and to indigenous communities that rely on wild resources for nutritional and cultural wellbeing. Because indigenous communities and wildlife populations are interdependent, assessing how human activities impact traditional harvest practices can advance our understanding of the human dimensions of wildlife management. Indigenous communities across Arctic Alaska have expressed concern over the last four decades that low-flying aircraft interfere with their traditional harvest practices. For example, communities often have testified that aircraft disturb caribou (Rangifer tarandus) and thereby reduce harvest opportunities. Despite this longstanding concern, little research exists on the extent of aircraft activity in Arctic Alaska and on how aircraft affect the behavior and perceptions of harvesters. Therefore, the overarching goal of my research was to highlight the importance of aircraft-harvester conflict in Arctic Alaska and begin to address the issue using a scientific and community-driven approach. In Chapter 1, I demonstrated that conflict between aircraft and indigenous harvesters in Arctic Alaska is a widespread, understudied, and complex issue. By conducting a meta-analysis of the available literature, I quantified the deficiency of scientific knowledge about the impacts of aircraft on rural communities and traditional harvest practices in the Arctic. My results indicated that no peer-reviewed literature has addressed the conflict between low-flying aircraft and traditional harvesters in Arctic Alaska. I speculated that the scale over which aircraft, rural communities, and wildlife interact limits scientists' ability to determine causal relationships and therefore detracts from their interest in researching the human dimension of this social-ecological system. Innovative research approaches like soundscape ecology could begin to quantify interactions and provide baseline data that may foster mitigation discourses among stakeholders. In Chapter 2, I employed a soundscape-ecology approach to address concerns about aircraft activity expressed by the Alaska Native community of Nuiqsut. Nuiqsut faces the greatest volume of aircraft activity of any community in Arctic Alaska because of its proximity to intensive oil and gas activity. However, information on when and where these aircraft are flying is unavailable to residents, managers, and researchers. I worked closely with Nuiqsut residents to deploy acoustic monitoring systems along important caribou harvest corridors during the peak of caribou harvest, from early June through late August 2016. This method successfully captured aircraft sound and the community embraced my science for addressing local priorities. I found aircraft activity levels near Nuiqsut and surrounding oil developments (12 daily events) to be approximately six times greater than in areas over 30 km from the village (two daily events). Aircraft sound disturbance was 26 times lower in undeveloped areas (Noise Free Interval =13 hrs) than near human development (NFI = 0.5 hrs). My study provided baseline data on aircraft activity and noise levels. My research could be used by stakeholders and managers to develop conflict avoidance agreements and minimize interference with traditional harvest practices. Soundscape methods could be adapted to rural regions across Alaska that may be experiencing conflict with aircraft or other sources of noise that disrupt human-wildlife interactions. By quantifying aircraft activity using a soundscape approach, I demonstrated a novel application of an emerging field in ecology and provided the first scientific data on one dimension of a larger social-ecological system. Future soundscape studies should be integrated with research on both harvester and caribou behaviors to understand how the components within this system are interacting over space and time. Understanding the long-term impacts to traditional harvest practices will require integrated, cross-disciplinary efforts that collaborate with communities and other relevant stakeholders. Finally, my research will likely spark efforts to monitor and mitigate aircraft impacts to wildlife populations and traditional harvest practices across Alaska, helping to inform a decision-making process currently hindered by an absence of objective data

Relation between vibrotactile perception thresholds and reductions in finger blood flow induced by vibration of the hand at frequencies in the range 8–250 Hz

Purpose: this study investigated how the vasoconstriction induced by vibration depends on the frequency of vibration when the vibration magnitude is defined by individual thresholds for perceiving vibration [i.e. sensation levels (SL)].Methods: fourteen healthy subjects attended the laboratory on seven occasions: for six vibration frequencies (8, 16, 31.5, 63, 125, or 250 Hz) and a static control condition. Finger blood flow (FBF) was measured in the middle fingers of both hands at 30-second intervals during five successive periods: (i) no force or vibration, (ii) 2-N force, no vibration, (iii) 2-N force, vibration, (iv) 2-N force, no vibration, (v) no force or vibration. During period (iii), vibration was applied to the right thenar eminence via a 6-mm diameter probe during ten successive 3-min periods as the vibration magnitude increased in ten steps (?10 to +40 dB SL).Results: with vibration at 63, 125, and 250 Hz, there was vasoconstriction on both hands when the vibration magnitude reached 10 dB SL. With vibration at 8, 16, and 31.5 Hz, there was no significant vasoconstriction until the vibration reached 25 dB SL. At all frequencies, there was greater vasoconstriction with greater magnitudes of vibration.Conclusions: it is concluded that at the higher frequencies (63, 125, and 250 Hz), the Pacinian channel mediates vibrotactile sensations near threshold and vasoconstriction occurs when vibration is perceptible. At lower frequencies (8, 16, and 31.5 Hz), the Pacinian channel does not mediate sensations near threshold and vasoconstriction commences at greater magnitudes when the Pacinian channel is activate