Relevant bibliographies by topics / Neurophysiology; Amplitude variation; Noise

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  1. Journal articles
  2. Dissertations / Theses
  3. Conference papers

Academic literature on the topic 'Neurophysiology; Amplitude variation; Noise'

Author: Grafiati
Published: 4 June 2021
Last updated: 3 February 2022

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Journal articles on the topic "Neurophysiology; Amplitude variation; Noise"

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Eberhard, Monika J. B., Jan-Hendrik Schleimer, Susanne Schreiber, and Bernhard Ronacher. "A temperature rise reduces trial-to-trial variability of locust auditory neuron responses." Journal of Neurophysiology 114, no. 3 (September 2015): 1424–37. http://dx.doi.org/10.1152/jn.00980.2014.

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The neurophysiology of ectothermic animals, such as insects, is affected by environmental temperature, as their body temperature fluctuates with ambient conditions. Changes in temperature alter properties of neurons and, consequently, have an impact on the processing of information. Nevertheless, nervous system function is often maintained over a broad temperature range, exhibiting a surprising robustness to variations in temperature. A special problem arises for acoustically communicating insects, as in these animals mate recognition and mate localization typically rely on the decoding of fast amplitude modulations in calling and courtship songs. In the auditory periphery, however, temporal resolution is constrained by intrinsic neuronal noise. Such noise predominantly arises from the stochasticity of ion channel gating and potentially impairs the processing of sensory signals. On the basis of intracellular recordings of locust auditory neurons, we show that intrinsic neuronal variability on the level of spikes is reduced with increasing temperature. We use a detailed mathematical model including stochastic ion channel gating to shed light on the underlying biophysical mechanisms in auditory receptor neurons: because of a redistribution of channel-induced current noise toward higher frequencies and specifics of the temperature dependence of the membrane impedance, membrane potential noise is indeed reduced at higher temperatures. This finding holds under generic conditions and physiologically plausible assumptions on the temperature dependence of the channels' kinetics and peak conductances. We demonstrate that the identified mechanism also can explain the experimentally observed reduction of spike timing variability at higher temperatures.
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Yu, Gary. "Offset‐amplitude variation and controlled‐amplitude processing." GEOPHYSICS 50, no. 12 (December 1985): 2697–708. http://dx.doi.org/10.1190/1.1441890.

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The partition of plane seismic waves at plane interfaces introduces changes in seismic amplitude which vary with angle of incidence. These amplitude variations are a function of the elastic parameters of rocks on either side of the interface. Controlled‐amplitude processing is designed to obtain the true amplitude information which is geologic in origin. The offset‐amplitude information may be successfully used to predict the fluid type in reservoir sands. Various tests were carried out on a seismic profile from the Gulf Coast. The processing comparison emphasized the effects and pitfalls of trace equalization, coherent noise, offset, and surface‐related problems. Two wells drilled at amplitude anomaly locations confirmed the prediction of hydrocarbons from offset‐amplitude analysis. Furthermore, controlled‐amplitude processing provided clues in evaluating reservoir quality, which was not evident on the conventional relative amplitude data.
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Wilson, Hamish, and Lutz Gross. "Amplitude variation with offset-friendly bootstrapped differential semblance." GEOPHYSICS 82, no. 5 (September 1, 2017): V297—V309. http://dx.doi.org/10.1190/geo2016-0395.1.

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Spectral noise, low resolution, and attenuation of semblance peaks due to amplitude variation with offset (AVO) anomalies hamper the reliability of velocity analysis in the semblance spectrum for seismic data processing. Increasing resolution and reducing noise while accounting for AVO has posed a challenge in various semblance schemes due to a trade-off in resolution and AVO detectability. A new semblance scheme is introduced that aims to remove this trade-off. The new scheme uses the concepts of bootstrapped differential semblance with trend-based AB semblance. Results indicate that the new scheme indeed increases spectral resolution, reduces noise, and accounts for AVO anomalies. These improvements facilitate velocity control for automatic and manual picking methods and, hence, provide a means for more reliable apparent velocity models.
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Cooper, Steven. "Wind Farm Noise—Modulation of the Amplitude." Acoustics 3, no. 2 (June 1, 2021): 364–90. http://dx.doi.org/10.3390/acoustics3020025.

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The operation of a wind turbine results in a series of pulses where there is a significant instantaneous increase in the amplitude of the pressure signal, dependent upon the wind speed at the turbine blades. The variations in the amplitude of the sound being emitted can be significant at receiver locations both as an audible and inaudible sound. The modulation of the A-weighted amplitude of the acoustic signature for wind turbines is often referred to as “amplitude modulation”. Criteria have been proposed in the UK to define “excessive amplitude modulation”. In a technical sense, the general descriptor for wind turbine amplitude modulation is incorrect. The correct term for the variation of the A-weighted level is modulation of the amplitude. The rate of the modulation of the dB(A) level occurs at the blade pass frequency, which is in the infrasound region. Turbines can exhibit amplitude modulation in the low frequency region. The differences between amplitude modulation and modulation of the amplitude occurring at an infrasound rate are discussed in the context for an environmental assessment of a wind farm with respect to permit conditions and a simplified method of assessment with respect to the Modulation Index.
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Chen, Yangkang, Weilin Huang, Yatong Zhou, Wei Liu, and Dong Zhang. "Plane-wave orthogonal polynomial transform for amplitude-preserving noise attenuation." Geophysical Journal International 222, no. 3 (June 20, 2020): 1789–804. http://dx.doi.org/10.1093/gji/ggaa188.

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SUMMARY Amplitude-preserving data processing is an important and challenging topic in many scientific fields. The amplitude-variation details in seismic data are especially important because the amplitude variation is directly related with the subsurface wave impedance and fluid characteristics. We propose a novel seismic noise attenuation approach that is based on local plane-wave assumption of seismic events and the amplitude preserving capability of the orthogonal polynomial transform (OPT). The OPT is a way for representing spatially correlative seismic data as a superposition of polynomial basis functions, by which the random noise is distinguished from the useful energy by the high orthogonal polynomial coefficients. The seismic energy is the most correlative along the structural direction and thus the OPT is optimally performed in a flattened gather. We introduce in detail the flattening operator for creating the flattened dimension, where the OPT can be applied subsequently. The flattening operator is created by deriving a plane-wave trace continuation relation following the plane-wave equation. We demonstrate that both plane-wave trace continuation and OPT can well preserve the strong amplitude variation existing in seismic data. In order to obtain a robust slope estimation performance in the presence of noise, a robust slope estimation approach is introduced to substitute the traditional method. A group of synthetic, pre-stack and post-stack field seismic data are used to demonstrate the potential of the proposed framework in realistic applications.
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Kim, Hack-Yoon. "Speech Enhancement Using Robust MAP Amplitude Spectral Estimator for Arbitrary Noise Variation." Journal of Korean Institute of Information Technology 14, no. 2 (February 29, 2016): 37. http://dx.doi.org/10.14801/jkiit.2016.14.2.37.

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Ojima, Hirotaka, Kazutaka Nonomura, Li Bo Zhou, Jun Shimizu, and Teppei Onuki. "Design of Digital Filters for Si Wafer Surface Profile Measurement - Denoising by Total Variation." Key Engineering Materials 516 (June 2012): 332–36. http://dx.doi.org/10.4028/www.scientific.net/kem.516.332.

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In the semiconductor industry, high resolution and high accuracy measurement is needed for the geometric evaluation of Si wafers. The flatness parameters are important to evaluate the wafer profile and are required to be the same level as the design rule of IC, and the tolerance for flatness is very tight. According to SEMI (Semiconductor Equipment and Materials International) standards, the required wafer flatness will be 22 nanometres by the year 2016. However, to obtain a higher resolution for sensors, the uncertainty becomes very large compared to the resolution and influences the measured data when the noise is increased. High resolution instruments always incorporate a certain degree of noise. In the presence of noise, form parameters are normally biased. Correction and compensation need a large population of measurements to analytically estimate both bias and uncertainty. The estimation is still far from perfect because of the nature of noise. Another approach is to extract a true profile by filtering noise from the measured data. For the purpose of noise reduction, low-pass filters by Gaussian smoothing and Fourier transform are often used. The noise is normally considered to be a component of small deviation (amplitude) with high frequency which also takes a normal distribution around zero. However these conventional filters can remove the noise in the spatial frequency domain only. So, it is essential to design a filter capable of removing the noise both in the spatial frequency domain and the amplitude component. Thus, we have designed and developed new type of digital filter for denoising. We introduce two new digital filters. One is wavelet transform capable of denoising in the spatial frequency domain and amplitude component, and the other is total variation that can be applied to discontinuous signals without introducing artificial Gibbs Effects.
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Nykaza, Edward T., and Dan Valente. "Community and individual variation in response to noise from high amplitude impulsive sounds." Journal of the Acoustical Society of America 132, no. 3 (September 2012): 2086. http://dx.doi.org/10.1121/1.4755703.

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Rutherford, Steven R. "Noise‐discriminating, statistical‐amplitude compensation for AVO analysis." GEOPHYSICS 58, no. 12 (December 1993): 1831–39. http://dx.doi.org/10.1190/1.1443398.

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Statistical amplitude balancing/compensation techniques are widely used in the industry to prepare seismic data for amplitude variation with offset (AVO) processing and analysis. The intent of such statistical techniques is to compensate the data for the average signal decay with offset such that reflectors that are anomalous with respect to this average decay can be detected and analyzed. Statistical amplitude compensation techniques, however, suffer from a serious flaw when applied to data sets having low signal‐to‐noise ratios (S/N) that vary with offset. An artifact of this flaw is often a suppression of the AVO effects one is trying to detect. When S/N is low and decreases with offset, as is usually the case, the rms amplitude measurements that statistical techniques are based upon become increasingly dominated by noise as offset increases. This can lead to a suppression of the far offsets by the balancing scalars responding to a noise level that is increasing with offset. A noise‐discriminating, statistical‐amplitude compensation technique can be designed that counteracts the detrimental effects of noise. This technique is based on the premise that a common‐midpoint (CMP) ensemble average of crosscorrelations of like offset data is proportional to the average signal amplitude corresponding to that offset. The average signal decay with offset can be estimated with this technique and used to amplitude compensate a data set for AVO analysis. The noise‐discriminating statistical technique performs extremely well on synthetic data. When applied to a Gulf of Mexico data set having poor S/N characteristics, the technique also performs well and offers encouragement that it will be useful in actual practice.
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ZHANG, Y. X., C. C. BOON, and K. S. YEO. "DESIGN AND ANALYSIS OF A 2.4 GHz HYBRID TYPE AUTOMATIC AMPLITUDE CONTROL VCO WITH FORWARD NOISE REDUCTION." Journal of Circuits, Systems and Computers 23, no. 04 (April 2014): 1450048. http://dx.doi.org/10.1142/s0218126614500480.

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This paper presents a voltage-controlled oscillator (VCO) with automatic amplitude control (AAC) loop. The proposed AAC VCO employs a hybrid type AAC loop and targets the Industrial, Scientific and Medical (ISM) band applications. The proposed AAC loop can also prevent the AAC from generating extra noise to the VCO and avoid stability problem which is common for conventional AAC loop. Detail transient analysis of this AAC VCO is derived. Based on this analysis, design steps applicable for such type of AAC loop is obtained. Measurement result shows the peak amplitude variation over the operation range of 2.25–2.54 GHz is less than 9 mV (without the AAC loop, amplitude variation can be as large as 40 mV, or 22.2% for 180 mV amplitude). Power consumption of the proposed AAC VCO is 4.5 mW while the power consumed by the loop is 0.8 mW and phase noise is -105 dBc/Hz at 100 kHz offset frequency. Worst case settling time is less than 10.5 μs.
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Dissertations / Theses on the topic "Neurophysiology; Amplitude variation; Noise"

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Wahl, Linda Marie. "Sources of quantal variance in synaptic transmission." Thesis, University of Oxford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318451.

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Conference papers on the topic "Neurophysiology; Amplitude variation; Noise"

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Holl, Alexandre Faraco, and Alex Cardoso Santos. "Determination of the amplitude of the friction forces variation inherent to a coastdown test (typical noise amplitude), comparing it with the aerodynamic drag force and raise the sensitive of the coastdown test to the variation of the vehicle coefficient of drag (Cd)." In 2018 SAE Brasil Congress & Exhibition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2018. http://dx.doi.org/10.4271/2018-36-0187.

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Park, Kwangkun, Hanshin Seol, and Soogab Lee. "Numerical Analysis of Tip Vortex Cavitation Behavior and Noise on Hydrofoil." In ASME 2006 2nd Joint U.S.-European Fluids Engineering Summer Meeting Collocated With the 14th International Conference on Nuclear Engineering. ASMEDC, 2006. http://dx.doi.org/10.1115/fedsm2006-98510.

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In this study, tip vortex cavitation behavior and noise are numerically analyzed. Eulerian-Lagrangian approach is used to simulate the tip vortex cavitation on the hydrofoil. In this approach, the flow field and cavitation behavior are computed by Eulerian and Lagrangian point of view, respectively. The vortex flow field is simulated by combining Moore and Saffman’s vortex core radius variation equation with Sculley vortex model. The tip vortex cavitation behavior is analyzed by coupled Rayleigh-Plesset equation and trajectory equation based on Newton’s 2nd law. Kamiirisa’s experimental nuclei data are adopted to produce computational cavitation nuclei population and the nuclei are released in the vortex flow field. The tip vortex cavitation trajectories and radius variations of the nuclei are calculated according to the initial sizes of the nuclei. Noise is analyzed using time dependent cavitation bubble position and radius variation data. When the acting pressure on the nucleus goes down below the vapor pressure, the nucleus grows into a cavitation bubble. And, the cavitation bubble emits very high amplitude noise during collapse stage. This study may become a foundation of the vortex cavitation study.
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Ryan, Teresa J., John A. Judge, and Joseph F. Vignola. "Identification of Mass Distribution of Nominally Identical Microresonator Arrays in the Presence of Measurement Noise." In ASME 2011 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/detc2011-48562.

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The use of micro- and nanoscale mechanical resonators for mass detection is a maturing concept. Recently, researchers have begun to consider coupled arrays of resonators and the notion of examining system eigenmodes as well as resonant frequencies to extract information about the system. This paper describes a method for the use of measured eigenmodes of a linear chain of nominally identical oscillators to identify the masses of the individual oscillators. This allows characterization of initial mass variation as well as changes due to the presence of one or more target analytes. This work uses numerical simulation to explore the sensitivity of this method to measurement noise. Mass identification is shown to be more accurate on oscillators with significant vibration amplitude in a given eigenmode. We discuss various averaging techniques for combining results from multiple eigenmodes to reduce sensitivity to noise.
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Mori, Hideo, Kyohei Maeda, Masato Furukawa, and Masao Akiyoshi. "Measurement Technique for Unsteady Low-Speed Flow Fields Using Poly(TMSP)-Based Pressure Sensitive Paint." In ASME/JSME/KSME 2015 Joint Fluids Engineering Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/ajkfluids2015-20700.

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Nonstationary analysis of flow field is required to detect the source of aerodynamic noise, in order to accomplish the reduction of aerodynamic noise in life environment, including low-frequency noise, which may be harmful for human health. Pressure sensitive paint (PSP) is a quantitative pressure visualization technique on solid surfaces based on oxygen quenching of luminescent molecule. Polymer-type PSP composed of PtTFPP, a luminescent molecule with high oxygen quenching probability, and poly(TMSP), a glassy polymer with high oxygen permeability, has high pressure sensitivity for low-speed flow field. However, the pressure sensitivity of the polymer-type PSP for nonstationary pressure change has not been examined enough. In this study, we investigate the time response of the poly(TMSP)-based PSP, to evaluate the feasibility of the polymer-type PSP as a measurement tool for nonstationary low-speed flows, when the frequency of pressure fluctuation is relatively low. Because response time of polymer-type PSP is proportional to the square of the thickness of the PSP layer, we prepare thinner-layer PSP to increase the response speed by reducing the amount of polymer. The polymer-type PSP is applied to measurement of nonstationary pressure distribution around a circular cylinder in low-speed flow, and compare the amplitude spectra of PSP and that of pressure probe, which are obtained by FFT analysis. As a result it is clarified that the sensitivity of the PSP for pressure variation lower than 100Hz is as high as that for stationary pressure. For pressure variation higher than 100Hz the sensitivity decreases as the frequency of pressure variation increases, but pressure variation with the amplitude of about 300Pa can be detected by the poly(TMSP)-based PSP even if the frequency is as high as 850Hz. Furthermore we have visualized the distribution of the integrated intensity of the PSP amplitude spectrum around the peak, to visualize the area with large pressure variation on the cylinder surface.
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Lu, Jian-Ming, Chun-Yi Wu, Cheng-Shiu Hung, Wen-Tung Chien, Wang-Long Li, Chi-Chuan Hwang, and Yun-Che Wang. "Dynamical Behavior of Water Inside a Capped Single-Walled Carbon Nanotube." In ASME 2008 First International Conference on Micro/Nanoscale Heat Transfer. ASMEDC, 2008. http://dx.doi.org/10.1115/mnht2008-52227.

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Dynamical behavior of water confined inside a capped single-walled carbon nanotube (SWCNT) is investigated at different temperatures via the Molecular Dynamics (MD) Simulation method. Water in a SWCNT behaves in the fashion of random walk and increases amplitudes with temperature. Moreover, the SWCNT’s tip vibrates more significantly as temperature increases. The water molecules embedded nanotubes exhibit less thermal noise amplitude, indicating increases in effective stiffness in the water-nanotube composite. Further, the vibrational amplitude of a water-embedded SWCNT’s tip is more noticeable during the initial transient state at the beginning of our MD simulations, and gradually decays, and reaches a steady state, as MD simulation time increases. The variation of vibrating amplitude of the SWCNT’s tip increases linearly as temperature increases when no water is present inside. The tip vibration exhibits the largest amplitude when temperature is at the boiling point of water. Moreover, the tip vibration increases monotonically as temperature increases, providing information to estimate the effective Young’s modulus of the water-nanotube composite. The diffusion pathways of water inside a SWCNT are also studied in terms of temperature changes.
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Bozak, Richard F. "Measurements of Multiple Pure Tone Propagation From a High Bypass Turbofan Rotor in an Internal Flow Facility." In ASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-14161.

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Abstract An important noise source in modern high bypass ratio turbofans is from multiple pure tones produced by the fan during takeoff. An experiment conducted on a 1.5 pressure ratio fan in an internal flow facility provided dynamic pressure measurements to investigate multiple pure tone generation and propagation. Since multiple pure tones are generated by blade shock variation primarily due to the fan’s blade stagger angle differences, the blade stagger angles were measured with an array of over-the-rotor dynamic pressure transducers. Multiple pure tone measurements were made with 30 wall-mounted dynamic pressure transducers from 0.4 to 1.1 diameters upstream of the rotor. Measured blade stagger angle differences correspond to the the shock amplitude variation measured upstream. The acoustic field was extracted from the dynamic pressure signals using principal component analysis as well as duct mode beamforming. Shocks traveling out the inlet were found to couple to duct modes propagating at similar angles. Over-the-rotor acoustic liners appear to reduce rotor shock variation resulting in a reduction of sub-harmonic multiple pure tone sound pressure levels by 3–4 dB.
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Madadnia, Jafar, Mustafa Shekeb, and Thimantha Ulluwishewa. "Experimental Study of Aerodynamic Noise From the Trailing Edge and Leading Edge of Blades in a Coaxial-Double Shaft Fan." In ASME 2013 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/fedsm2013-16429.

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Proactive acoustic noise control technologies in wind turbines and blowers have in recent years been the focus of intensive research to integrate wind turbines in residential building and to address public concerns on noise pollution. However efforts to understand the mechanics has been inconclusive, mainly due to the complexity and commercial confidentiality of the topic. The paper reports on the experimental investigation on two methods in controlling aerodynamic noise. A counter-rotating-double-row-turbine with variable gap/spacing (s) was designed, built and tested. Serrations were designed and attached on the leading edge and the trailing edge of the blades to proactively control aerodynamic noise. The model was operated in fan-mode and air velocity, shaft-revolution; electric-fan-power, acoustic noise amplitude (dB) and Centre frequency (CF in Hz) were measured for a number of spacing and serrations. Coefficients of Performance (COP), dB, CF were plotted against tip speed (TS). It was noticed that: • The double-shaft-fan has operated quieter than the single shaft fan especially as TS decreases. Acoustic noise (dB) dropped 20% at TS = 4m/s to less than 2% at TS = 10m/s. Efficiency and CF increased in the double-shaft fan as TS increased. Spacing variation between blade-rows had insignificant effect on the dB, Cf, and efficiency. • Serrations on single-shaft fan have also reduced dB (up to 10%), increased efficiency and CF with more positive effects with the serrations on the leading edge than the trailing edge. Serrations are more effective at higher TS range. • Serrations on a double-shaft fan with an optimum spacing, reduced acoustic noise (dB) only allow speeds [at TS <4m/s]. However minor improvement was noticed in efficiency or noise frequency.
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Biedermann, Till M., F. Kameier, and C. O. Paschereit. "Optimised Test Rig for Measurements of Aerodynamic and Aeroacoustic Performance of Leading Edge Serrations in Low-Speed Fan Application." In ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/gt2018-75369.

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With the aim of analysing the efficiency of leading edge serrations under realistic conditions, an experimental rig was developed where a ducted low-speed fan is installed that allows to gather data of both, aerodynamic and aeroacoustic nature. Turbulent inflow conditions were generated via biplane-square grids, resulting in turbulence intensities of different magnitude and of high isotropic character that were quantified by use of hotwire measurements. The fan blades were designed according to the NACA65(12)-10 profile with interchangeable features and an independently adjustable angle of attack. Altogether, five different parameters can be analysed, namely the serration amplitude and wavelength, the angle of attack, the inflow turbulence and the rotational speed. In addition, the blade design allows for a variation of the blade skew, sweep and dihedral as well. The presented work focusses on validating and optimising the test rig as well as a detailed quantification of the turbulent inflow conditions. Furthermore, first aerodynamic and aeroacoustic results of fan blades with straight leading edges are compared to those of serrated leading edges. The aerodynamic performance was found to be mainly affected by the serrations as a function of the serration amplitude. Aeroacoustically, a clear sensitivity towards different incoming turbulence intensities and serration parameters was detected, showing significant broadband noise reduction below 2 kHz with an overall noise reduction of ΔOASPL = 3.4 dB at maximum serration amplitudes and minimum wavelengths.
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Kim, J. H., G. P. Lee, C. H. Lim, and S. Lee. "Design and Verification of Cooling Fans for Engine Rooms of Mobile Hydraulics Vehicles." In ASME-JSME-KSME 2019 8th Joint Fluids Engineering Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/ajkfluids2019-5607.

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Abstract To provide an engine room of mobile hydraulic vehicle with an effective cooling for the combination set of a radiator, a charge air cooler, and an oil cooler, a 500mm-diameter, axial fan is designed to have a 8,800 m3/hr at a resistance of 20mm Aq static pressure with a sound power level less than 86 LwA. The design parameters of sweep angle amplitude, wavelength of sweep angle change, airfoil type, and stagger angle are examined in terms of fan performance and its sound power generation. The surface curvatures generated by the sinusoidal sweep angle variation in the radial direction are proved to result in quite different flow patterns, thereby different types of specific sound power characteristics at the same flowrate. The acoustic noise sources are examined and discussed by using an acoustic imaging technique.
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Wilson, Mark J., Mehmet Imregun, and Abdulnaser I. Sayma. "The Effect of Stagger Variability in Gas Turbine Fan Assemblies." In ASME Turbo Expo 2006: Power for Land, Sea, and Air. ASMEDC, 2006. http://dx.doi.org/10.1115/gt2006-90434.

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Fan blades of high bypass ratio gas turbine engines are subject to substantial aerodynamic and centrifugal loads, producing the well-known phenomenon of fan blade untwist. The accurate prediction of the running geometry, as opposed to the cold geometry at rest, is crucial in the assessment of aerodynamic performance, vibratory response and noise production of the fan. The situation is further complicated by the fact that some geometric variation is inevitable even for the state-of-the-art manufacturing processes used. The aim of this paper is to investigate the effect of static stagger variability on the dynamic untwist behaviour of fan assemblies. An aeroelastic model was used to show that under certain conditions the stagger pattern changes significantly, both in form and amplitude, relative to the static configuration. At other conditions, a strong correlation between the running and static patterns is demonstrated.
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