Energy fluctuations in recorder pipes during transient sound attacks and steady state sound

2021 ◽  
Vol 263 (3) ◽  
pp. 2949-2960
Author(s):  
Hirofumi Onitsuka ◽  
Tetsuro Shoji ◽  
Katsuya Uchida ◽  
Akira Miki
Keyword(s):  
Steady State ◽  
Sound Field ◽  
The Self ◽  
Sound Power ◽  
Fluid Analysis ◽  
Sustained Oscillations ◽  
Spatial Fluctuations ◽  
Main Factors ◽  
Temporal And Spatial ◽  
Fundamental Mechanism

The evaluation of temporal and spatial fluctuations of energy using compressible fluid analysis is proposed as an effective method to clarify the fundamental mechanism of the self-sustained oscilla-tions in a actual recorder. The main factors of the self-sustained oscillations are investigated in more detail by evaluating not only the steady state of the sound where the flow field and the sound field are completely coupled, but also the characteristics at the attack transient of the sound before the coupling is established. By analyzing the large energy fluctuations that occur just below the edge of the labium in the attack transient, it was shown that this phenomenon may be one of the main causes of the self-sustained oscillations. And the characteristics of the energy fluctuations and sound power generation during the steady state of the sound are discussed. It was also focused on the energy variations in another region that is near the exit of the windway.

scholarly journals Temporal and spatial fluctuations of phytoplankton in a tropical coastal lagoon, southeast Brazil

2007 ◽  
Vol 67 (3) ◽  
pp. 475-483 ◽  
Author(s):  
S. Melo ◽  
RL. Bozelli ◽  
FA. Esteves
Keyword(s):  
Phytoplankton Biomass ◽  
Dominant Species ◽  
Phytoplankton Community ◽  
Domestic Sewage ◽  
Nutrient Concentrations ◽  
Spatial And Temporal Variability ◽  
Spatial Fluctuations ◽  
Main Factors ◽  
Direct Input ◽  
Temporal And Spatial

Spatial and temporal variability of the phytoplankton community in the tropical coastal Imboassica lagoon, an environment naturally isolated from the ocean by a narrow sandbar, was analysed every two weeks for 19 months by sampling three sites. During this study, the lagoon received direct input of marine water three times, resulting in remarkable salinity, nutrient concentrations and phytoplankton biomass variations in both temporal and spatial aspects. The phytoplankton biomass presented relatively low values ranging, on average, from 0.54 mg.L-1 in the station closest to the sea (station 1) to 1.34 mg.L-1 in the station close to a macrophyte bank (station 3). Diatoms and cryptomonads dominated in stations 1 and 2 (located relatively close to station 1, yet receiving the runoff of domestic sewage), and euglenoids, cryptomonads and dinoflagellates at station 3. Stations 1 and 2 usually presented the same dominant species but station 2 presented a higher phytoplankton biomass. On the other hand, station 3 showed more similar results concerning phytoplankton biomass with station 2, however the dominant species were usually different. The high fluctuations of salinity and the reduced nutrient availability are pointed out as the main factors structuring the dynamics of the phytoplankton community at the Imboassica lagoon.

Impinging planar jets: hysteretic behaviour and origin of the self-sustained oscillations

2021 ◽  
Vol 913 ◽  
Author(s):  
Alessandro Bongarzone ◽  
Arnaud Bertsch ◽  
Philippe Renaud ◽  
François Gallaire
Keyword(s):  
The Self ◽  
Hysteretic Behaviour ◽  
Sustained Oscillations

Abstract

Associative Behaviors of a Novel Series of Amphiphilic Statistical Tripolymers

2014 ◽  
Vol 472 ◽  
pp. 603-606
Author(s):  
Xu Wu ◽  
Hong Hua Xiao ◽  
Ji Juan Wang ◽  
Xiao Xuan Xie ◽  
Jia Wei Lin ◽  
...  
Keyword(s):  
Steady State ◽  
Self Assembly ◽  
Sulfonic Acid ◽  
The Self ◽  
Steady State Fluorescence

A novel series of brush-like amphiphilic statistical tripolymers were designed and prepared by polymerization of amphiphilic macromonomer 2-(acrylamido)-dodecane sulfonic acid (AMC12S, 10 to 90 mol %), with hindrance units sodium p-styrenesulfonate (SSS, 0 to 5 mol %), and 2-(acrylamido)- 2-methylpro-panesulfonic acid (AMPS). The self-assembly behaviors of these tripolymers were investigated using steady-state fluorescence, and the increase of amphiphilic units results in a decrease of microdomain polarity and polymer concentrations for assembly, while the increase of hindrance units leads little change of microdomain polarity.

scholarly journals Destabilizing evolutionary and eco-evolutionary feedbacks drive empirical eco-evolutionary cycles

2018 ◽  
Author(s):  
Michael H. Cortez ◽  
Swati Patel ◽  
Sebastian J. Schreiber
Keyword(s):  
Steady State ◽  
Empirical Studies ◽  
System Stability ◽  
Evolutionary Models ◽  
Sustained Oscillations ◽  
Ecological Feedbacks

ABSTRACTWe develop a method to identify how ecological, evolutionary, and eco-evolutionary feedbacks influence system stability. We apply our method to nine empirically-parameterized eco-evolutionary models of exploiter-victim systems from the literature and identify which particular feedbacks cause some systems to converge to a steady state or to exhibit sustained oscillations. We find that ecological feedbacks involving the interactions between all species and evolutionary and eco-evolutionary feedbacks involving only the interactions between exploiter species (predators or pathogens) are typically stabilizing. In contrast, evolutionary and eco-evolutionary feedbacks involving the interactions between victim species (prey or hosts) are destabilizing more often than not. We also find that while eco-evolutionary feedbacks rarely altered system stability from what would be predicted from just ecological and evolutionary feedbacks, eco-evolutionary feedbacks have the potential to alter system stability at faster or slower speeds of evolution. As the number of empirical studies demonstrating eco-evolutionary feedbacks increases, we can continue to apply these methods to determine whether the patterns we observe are common in other empirical communities.

scholarly journals Energy expenditure of trans-tibial amputees during ambulation at self-selected pace

1994 ◽  
Vol 18 (2) ◽  
pp. 84-91 ◽  
Author(s):  
R. S. Gailey ◽  
M. A. Wenger ◽  
M. Raya ◽  
N. Kirk ◽  
K. Erbs ◽  
...  
Keyword(s):  
Heart Rate ◽  
Steady State ◽  
Energy Expenditure ◽  
Energy Cost ◽  
Metabolic Cost ◽  
The Self ◽  
Healthy Male ◽  
Subject Pool

The purpose of this investigation was two-fold: 1) to compare the metabolic cost (VO2), heart rate (HR), and self-selected speed of ambulation of trans-tibial amputees (TTAs) with those of non-amputee subjects; and 2) to determine whether a correlation exists between either stump length or prosthesis mass and the energy cost of ambulation at the self-selected ambulation pace of TTAs. Subjects were thirty-nine healthy male non-vascular TTAs between the ages of 22 and 75 years (mean ± sd = 47 ± 16). All had regularly used their prosthesis for longer than six months and were independent of assistive ambulation devices. Twenty-one healthy non-amputee males aged 27–47 years (31 ± 6) served as controls. Subjects ambulated at a self-selected pace over an indoor course, with steady-state VO2, HR, and ambulation speed averaged across minutes seven, eight and nine of walking. Results showed that HR and VO2 for TTAs were 16% greater, and the ambulation pace 11% slower than the non-amputee controls. Significant correlations were not observed between stump length or prosthesis mass and the energy cost of ambulation. However, when the TTA subject pool was stratified on the basis of long and short stump length, the former sustained significantly lower steady-state VO2 and HR than the latter while walking at comparable pace. These data indicate that stump length may influence the metabolic cost of ambulation in TTAs.

The Dynamic Boundaries of The Self: Serial Dependence In Embodied Sense of Agency

2021 ◽  
Author(s):  
Yoni Stern ◽  
Inbar Ben-Yehuda ◽  
Danny Koren ◽  
ADAM ZAIDEL ◽  
Roy Salomon
Keyword(s):  
The Self ◽  
Sense Of Agency ◽  
Embodied Experience ◽  
Serial Dependence ◽  
Actual Movement ◽  
Spatial Domains ◽  
Temporal And Spatial ◽  
Embodied Self ◽  
External Stimuli ◽  
Over Time

The feeling of control over one’s actions, termed the Sense of Agency (SoA), delineates one’s experience as an embodied self. Although, this embodied experience is typically perceived as stable over time, recent theoretical accounts highlight the experience-dependent and dynamic nature of the embodied self. In this study we examined how recent experiences modulate SoA (i.e., serial dependence), and disambiguated the unique contributions of previous stimuli and choices on subsequent SoA judgments. In addition, we examined whether these effects persist across different domains of perceptual alteration. We analyzed two independent datasets of the Virtual Hand (VH) task (N = 100 participants) in which a sensorimotor conflict is introduced between the presented visual feedback and the actual movement performed. In Dataset 1, which included only temporal alterations, we found that previous stimuli recalibrate current perception, increasing the likelihood of the current choice to be different than the previous choice. Whereas previous choices induce a repetition bias increasing the likelihood to repeat choices across trials. Thus, previous external stimuli and self-generated choices exert opposing influences on SoA. We replicated these findings in Dataset 2, in which the VH task was tested with alterations in both temporal and spatial domains. In addition, we discovered that previous stimuli from a different perceptual domain exert a recalibration effect similar to stimuli from the same domain. Thus, SoA is constantly shaped by our previous subjective choices and objective stimuli experienced even across different perceptual domains. This highlights how SoA may act as unifying construct organizing our experience of the self over time and across perceptual experiences.

scholarly journals Temporal and Spatial Fluctuations in Widths of solar Euv Lines

1980 ◽  
Vol 51 ◽  
pp. 53-53
Author(s):  
R.G. Athay ◽  
O.R. White
Keyword(s):  
Line Width ◽  
Sound Speed ◽  
Large Scale ◽  
Small Cells ◽  
The Sun ◽  
Doppler Shifts ◽  
Spatial Fluctuations ◽  
Local Sound ◽  
Line Widths ◽  
Temporal And Spatial

AbstractAnalyses of some 300 hours of time sequences of solar EUV line profiles obtained with 0S0-8 show large fluctuations in line widths. At a given location on the sun, line widths fluctuate temporally on time scales ranging from less than a minute to over an hour. At any given time, line widths fluctuate spatially on a variety of scales ranging from active region size to arc second size. Temporal and spatial fluctuations are of approximately the same amplitude. Thus, the sun can be characterized by an aggregate of small cells in each of which line widths are fluctuating in time and which have random phases with respect to each other.Spatial fluctuations in line width are correlated with large scale spatial fluctuations in brightness for some lines but not for others. Temporal fluctuations in width are sometimes correlated with either Doppler shifts or intensity fluctuations, but more often such correlations are absent.For a given line, the line width varies through an extreme range of about a factor of two. Nonthermal components of line width vary from approximately the local sound speed to a small fraction of the sound speed.

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