Electrical Resistive Spiking of Fungi

2021 ◽  
pp. 1-7 ◽  
Author(s):  
Andrew Adamatzky ◽  
Alessandro Chiolerio ◽  
Georgios Sirakoulis
Keyword(s):  
Electrical Resistance ◽  
Electronic Devices ◽  
Low Frequency ◽  
High Amplitude ◽  
Average Amplitude ◽  
Average Width ◽  
C 23 ◽  
C 30 ◽  
Low Amplitude

We study long-term electrical resistance dynamics in mycelium and fruit bodies of oyster fungi P. ostreatus. A nearly homogeneous sheet of mycelium on the surface of a growth substrate exhibits trains of resistance spikes. The average width of spikes is c. 23[Formula: see text]min and the average amplitude is c. 1[Formula: see text]k[Formula: see text]. The distance between neighboring spikes in a train of spikes is c. 30[Formula: see text]min. Typically, there are 4–6 spikes in a train of spikes. Two types of electrical resistance spikes trains are found in fruit bodies: low frequency and high amplitude (28[Formula: see text]min spike width, 1.6[Formula: see text]k[Formula: see text] amplitude, 57[Formula: see text]min distance between spikes) and high frequency and low amplitude (10[Formula: see text]min width, 0.6[Formula: see text]k[Formula: see text] amplitude, 44[Formula: see text]min distance between spikes). The findings could be applied in monitoring of physiological states of fungi and future development of living electronic devices and sensors.

Frequency Response Analysis of Piecewise Nonlinear Vibration Isolator

2005 ◽  
Author(s):  
Patrick Stahl ◽  
G. Nakhaie Jazar
Keyword(s):  
Low Frequency ◽  
High Amplitude ◽  
Relative Displacement ◽  
Response Analysis ◽  
Frequency Response Analysis ◽  
State Behavior ◽  
Vibration Isolators ◽  
Short Period ◽  
Secondary Suspension ◽  
Low Amplitude

Non-smooth piecewise functional isolators are smart passive vibration isolators that can provide effective isolation for high frequency/low amplitude excitation by introducing a soft primary suspension, and by preventing a high relative displacement in low frequency/high amplitude excitation by introducing a relatively damped secondary suspension. In this investigation a linear secondary suspension is attached to a nonlinear primary suspension. The primary is assumed to be nonlinear to model the inherent nonlinearities involved in real suspensions. However, the secondary suspension comes into action only during a short period of time, and in mall domain around resonance. Therefore, a linear assumption for the secondary suspension is reasonable. The dynamic behavior of the system subject to a harmonic base excitation has been analyzed utilizing the analytic results derived by applying the averaging method. The analytic results match very well in the transition between the two suspensions. A sensitivity analysis has shown the effect of varying dynamic parameters in the steady state behavior of the system.

Oxygen Consumption by the Sea Anemone Calliactis Parasitica (Couch)

1980 ◽  
Vol 88 (1) ◽  
pp. 367-374
Author(s):  
A. E. BRAFIELD
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Concentration ◽  
Low Frequency ◽  
High Amplitude ◽  
Total Oxygen ◽  
Strip Chart ◽  
Calliactis Parasitica ◽  
Cycle Lengths ◽  
Mean Cycle ◽  
Low Amplitude

Oxygen consumption by Calliactis parasitica, measured in a continuousflow polarographic respirometer, yielded a slope of 0·92 when plotted against body weight on log scales. This high value is discussed in terms of the sea anemone's basically laminate nature. Strip-chart records of the oxygen concentration of water which had just passed a specimen of Calliactis commonly showed rhythmic fluctuations, either of low amplitude and high frequency or high amplitude and low frequency (mean cycle lengths 11 and 34 min respectively). The fluctuations are explained in terms of rhythmic muscular contractions which irrigate the enteron for respiratory purposes. Analysis of the slow fluctuations indicates that the endoderm is responsible for about 18% of the total oxygen consumption. The oxygen concentration of water in the enteron, measured and recorded continuously, was 4–27% of the air-saturation level. These strip chart records also frequently showed rhythmic fluctuations (mean cycle length 12 min), apparently resulting from the muscular contractions.

scholarly journals Primary Observational Distributions of δ Scuti Variables

2002 ◽  
Vol 185 ◽  
pp. 324-325
Author(s):  
E. Rodríguez ◽  
M. Breger
Keyword(s):  
High Amplitude ◽  
Visual Magnitude ◽  
Long Term Monitoring ◽  
Low Amplitude ◽  
Term Monitoring

The distribution of the known δ Scuti-type variables (R00 catalogue, Rodríguez et al., 2000) is analysed on the basis of some primary observational properties such as visual amplitude, period, visual magnitude and rotational velocities. The present distributions are also compared with those resulting from the earlier catalogue by Rodríguez et al. (1994, R94). The contributions from the Hipparcos, OGLE and MACHO long-term monitoring projects are also discussed. These contributions are quite different in the N-ΔV and N-V diagrams, in the sense that the variables discovered by the Hipparcos satellite are much brighter and with shorter periods than those discovered by the OGLE and MACHO projects.Concerning the N-ΔV diagram, we find that the gap, which was evident in the R94 catalogue for variables with visual amplitudes between 0.m1 to 0.m3, has disappeared. Thus, it seems that there is not a strict separation in two groups relative to the amplitude (low amplitude for variables with ΔV<0.m1 and high amplitude for variables with ΔV>0.m3) for the δ Scuti-type pulsatore.

The Motion of Strawberry Leaves in an Air-Assisted Spray Field and its Influence on Droplet Deposition

2021 ◽  
Vol 64 (1) ◽  
pp. 83-93
Author(s):  
Shuo Wu ◽  
Jizhan Liu ◽  
Jiangshan Wang ◽  
Dianhe Hao ◽  
Rongkai Wang
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
High Amplitude ◽  
Azimuth Angle ◽  
List Type ◽  
Droplet Deposition ◽  
Inclination Angles ◽  
Turbulence Effect ◽  
Spray Field ◽  
Low Amplitude

HighlightsA visualization method for the motion of strawberry leaves in an air-assisted spray field is proposed.Strawberry leaves showed two motion states in different critical velocity ranges of the sprayer airflow.The airflow instability and the turbulence effect are considered important factors for the leaf vibrations.A strawberry leaf azimuth angle in the range of 90° to 270° can provide good deposition with smaller droplets.Abstract. The reasonable motion of crop plants in an air-assisted spray field can improve droplet deposition. Therefore, this study focuses on the motion of strawberry leaves and the droplet deposition mechanism in an air-assisted spray field. First, this study proposes a descriptive method for strawberry leaf motion in an air-assisted spray field and clarifies the important influence of strawberry leaf motion on droplet deposition. Second, an experiment was performed on the motion and droplet capture of single strawberry leaves in multi-position postures in an air-assisted spray field. The results showed that the leaves had two motion states (i.e., low amplitude with low frequency and high amplitude with high frequency) at different airflow velocities and inclination angles, and the critical airflow velocity corresponding to the two motion states was determined to be 8.7 m s-1. When the azimuth angle of the strawberry leaves is in the range of 90° to 270°, a reasonable inclination angle of the airflow and the high frequency and high amplitude vibration state of the leaves driven by the airflow will provide good deposition and canopy penetration of droplets with smaller diameters. Keywords: Air-assisted spray field, Droplet deposition, Motion, Spray, Strawberry leaves.

scholarly journals Mechanistic Characteristics of Double Dominant Frequencies of Acoustic Emission Signals in the Entire Fracture Process of Fine Sandstone

Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3959 ◽  
Author(s):  
Chuangye Wang ◽  
Xinke Chang ◽  
Yilin Liu ◽  
Shijiang Chen
Keyword(s):  
Frequency Band ◽  
High Frequency ◽  
Fracture Process ◽  
Low Frequency ◽  
High Amplitude ◽  
Dominant Frequency ◽  
Band Energy ◽  
Ae Signal ◽  
Low Amplitude ◽  
Frequency Band Energy

To determine the intrinsic relationship between the acoustic emission (AE) phenomenon and the fracture pattern pertaining to the entire fracture process of rock, the present paper proposed a multi-dimensional spectral analysis of the AE signal released during the entire process. Some uniaxial compression AE tests were carried out on the fine sandstone specimens, and the axial compression stress–strain curves and AE signal released during the entire fracture process were obtained. In order to deal with tens of thousands of AE data efficiently, a subroutine was programmed in MATLAB. All AE waveforms of the tests were denoised by wavelet threshold firstly. The fast Fourier transform (FFT) and wavelet packet transform (WPT) were applied to the denoised waveforms to obtain the dominant frequency, amplitude, fractal, and frequency band energy ratio distribution. The results showed that the AE signal in the entire fracture process of fine sandstone had a double dominant frequency band of the low and high-frequency bands, which can be subdivided into low-frequency low-amplitude, high-frequency low-amplitude, high-frequency high-amplitude, and low-frequency high-amplitude signals, according to the magnitude. The low-frequency amplitude relevant fractal dimension and the high-frequency amplitude relevant fractal dimension each had turning points that corresponded to significant decreases in the middle and end stages of loading, respectively. The frequency band energy was mainly concentrated in the range of 0–187.5 kHz, and the energy ratios of some bands had different turning points, which appeared before the complete failure of the rock. It is suggested that the multi-dimensional spectral analysis may understand the failure mechanism of rock better.

Bradygastrias and Mixed Dysrhythmias

2003 ◽  
Keyword(s):  
Contractile Activity ◽  
Low Frequency ◽  
High Amplitude ◽  
Intraluminal Pressure ◽  
Pressure Sensing ◽  
Recording Channel ◽  
Low Amplitude ◽  
Peristaltic Contractions ◽  
The Relationship ◽  
Exact Origin

Bradygastrias are low-frequency electrogastrogram (EGG) waves that range from approximately 1.0 to 2.5 cycles per minute (cpm) . Some bradygastria waves are high amplitude and occupy the full scale of the EGG recording channel; others are very low amplitude and appear to be almost flatline. Bradygastrias have been recorded in patients with functional dyspepsia, diabetic and idiopathic gastropathy, and nausea of pregnancy. These patients have symptoms of abdominal discomfort, fullness, nausea, and vomiting. In this chapter, the causes of bradygastria patterns are reviewed and examples of bradygastrias are shown. EGGs also may have increased bradygastria and tachygastria waves, a pattern termed a mixed dysrhythmia. The exact origin of bradygastrias has been difficult to determine. In certain circumstances, the antrum contracts at 1.5 to 1.8 contractions per minute rather than the more recognized 3-per-minute contractions. Figure 8.1 indicates the relationship between EGG waves and low-frequency antral peristaltic contractions recorded from an intraluminal pressure sensing device during fasting and after infusion of erythromycin in healthy individuals. The antral contractions were recorded 3 and 1.5 cm from the pylorus. During fasting, 2-cpm EGG waves were present and correlated with 2-per-minute antral contractions. Each of these low-frequency contractions was associated with a low-frequency EGG wave (a negative deflection followed by a positive deflection). Irregular antral attractions also occur during fasting and may be reflected in the EGG as 1- to 2-cpm EGG waves. After erythromycin infusion, the EGG waves occurred at 1.0 to 1.5cpm and correlated with stronger antral contractions that occurred at the same frequency: 1.0 to 1.5 per minute. Thus, the bradygastria EGG frequencies correlated with the low-frequency antral contractions during fasting and after infusion of erythromycin. These studies indicate that, under certain conditions, bradygastria waves reflect low-frequency antral contractions. The fundus of the stomach normally contracts slowly at a rate from 0.5 to 1 contraction per minute.15 Thus, the low-frequency contractile activity of the fundus may also be reflected in the low frequency EGG signals in certain situations.

Recovery of Signals Distorted by Sensor Nonlinearity

2004 ◽  
Vol 126 (4) ◽  
pp. 848-859 ◽  
Author(s):  
Sugathevan Suranthiran ◽  
Suhada Jayasuriya
Keyword(s):  
Model Identification ◽  
Low Frequency ◽  
High Amplitude ◽  
Signal Recovery ◽  
Nonlinear Characteristics ◽  
Sensor Model ◽  
Physical Sensor ◽  
Low Amplitude ◽  
Unique Signal ◽  
Original Information

Considered in this paper is a framework for addressing sensor issues that are related to nonlinearity. When a signal is picked up by a nonlinear sensor, it is often the case that the high amplitude part of the signal is distorted by nonlinearity and the low amplitude part is indistinguishable from noise. The distorted output or sensed signal may no longer represent the original input signal due to the presence of high and low frequency foreign spikes in its frequency spectrum. This situation poses a challenging problem: Would it be possible to uniquely extract the original information from the distorted output? A treatment of this problem is given and it is shown that unique signal recovery is possible when the nonlinear characteristics of the sensor satisfy certain requirements. Based on the analysis, an algorithm is developed to recover finite length signals and its validity and efficiency are demonstrated by simulation results. When the sensor model is not available, it is shown how a model identification scheme may be incorporated into the developed scheme. Experiments performed on a physical sensor support the proposed recovery scheme.

scholarly journals Development of Piezoelectric Ultrasonic Thrombolysis Device for Blood Clot Emulsification

2012 ◽  
Vol 2012 ◽  
pp. 1-6
Author(s):  
Tao Li ◽  
Jan Ma ◽  
S. Dinesh Kumar ◽  
Adrian F. Low
Keyword(s):  
Blood Vessel ◽  
High Power ◽  
Vibration Mode ◽  
Pressure Field ◽  
Blood Clot ◽  
Low Frequency ◽  
High Amplitude ◽  
Field Pattern ◽  
Cavitation Effect ◽  
Low Amplitude

Ultrasonic thrombolysis is an effective method to treat blood clot thrombus in a blood vessel. This paper reports an OD 5 mm and an OD 10 mm piezoelectric thrombolysis transducers that vibrate longitudinally and generate a pressure field at the distal vibration tip. Studies of vibration mode, pressure field pattern, and cavitation effect were carried out. The transducers were also tested for blood clot emulsification. The results indicate both transducers are effective. The OD 10 mm transducer with a long transmission wire has shown to provide a strong cavitation effect and work effectively at low frequency, high amplitude, and high power conditions. The OD 5 mm transducer was found to operate effectively under higher frequency, low amplitude, and lower power conditions. The cavitation effect is moderate, which facilitates precision and controls over obtaining a more uniform emulsification result.

Managing Nonrandomly Varying Fisheries

1989 ◽  
Vol 46 (8) ◽  
pp. 1302-1308 ◽  
Author(s):  
J. Anthony Koslow
Keyword(s):  
Environmental Variability ◽  
Low Frequency ◽  
High Amplitude ◽  
Fish Population ◽  
Environmental Forcing ◽  
Fish Yield ◽  
Recruitment Variability ◽  
Age Structured ◽  
Constant Escapement

Theoretical studies indicate that constant effort or constant escapement harvest strategies are viable long-term management policies for fisheries influenced by random environmental variability. But the marine environment and fishery recruitment do not characteristically vary randomly: their time series tend to be autocorrelated. I examined the response of a model of an age-structured fish population to these harvest strategies, if recruitment is influenced by periodic variability. Variance in fish yield and the incidence of low stock size increased with both increasing amplitude and period length of environmental forcing. Sensitivity to environmental fluctuations increased sharply at periodicities between one and several times the generation length. Low-risk fisheries, which are subject to little nonrandom recruitment variability, may be satisfactorily managed by either management strategy, although constant effort harvesting provided greater stability to industry with little risk to the fish population. Neither strategy maintained stability in high-risk fisheries with high-amplitude, low-frequency recruitment variability, but a constant escapement policy minimized risk of stock collapse.

scholarly journals On the Procedure of Draught Rate Assessment in Indoor Spaces

2020 ◽  
Vol 10 (15) ◽  
pp. 5036
Author(s):  
Detelin Markov ◽  
Nikolay Ivanov ◽  
George Pichurov ◽  
Marina Zasimova ◽  
Peter Stankov ◽  
...  
Keyword(s):  
Thermal Environment ◽  
Low Frequency ◽  
High Amplitude ◽  
Time Interval ◽  
Cfd Simulations ◽  
Reliable Assessment ◽  
Unsteady Rans ◽  
Computational Fluid Dynamics Cfd ◽  
Indoor Spaces

The objective of the paper is to demonstrate the importance of the unsteady Computational Fluid Dynamics (CFD) simulations and long-term measurements for the reliable assessment of thermal comfort indoors, for proper categorization of the indoor thermal environment and for identifying the reasons for complaints due to draught discomfort. Numerical simulations and experimental measurements were applied in combination to study ventilation in a field laboratory, a university classroom with a controlled indoor environment. Strong unsteadiness of the airflow was registered both in the unsteady RANS results and the real-scale long-term velocity data measured with thermo anemometer. Low-frequency high-amplitude velocity fluctuations observed lead to substantial time variation of the draught rate. In case of categorization of a thermal environment, the point measurements or steady-state RANS computations would lead to wrong conclusions as well as they cannot be used for identification of the reasons for people’s complaints due to draught discomfort if strong unsteadiness of the airflow exists. It is demonstrated that the length of the time interval for draught rate (DR) assessment may not be universal if low-frequency high-amplitude pulsations are present in the room airflow.

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