A Modified Triaxial Apparatus for Soils under High-Frequency, Low-Amplitude Vibrations

This study investigated the endocrine background of follicle size changes during post-weaning altrenogest treatment. altrenogest-treated sows received a 20-mg dosage daily at 8.00 a.m. from Day –1 to Day 14 after weaning. On Day –1, only 3/13 altrenogest-treated sows showed LH pulses compared with 8/8 control sows (P = 0.001). On Day 0, control sows showed a typical high frequency–low amplitude LH pattern, indicative for recruitment of oestrogenic follicles. In altrenogest-treated animals on Day 0, half of the sows showed high frequency–high amplitude pulses from 4–5 h after weaning. In altrenogest-treated sows, average follicle size increased from 3.1 ± 0.5 mm on Day 0 to 4.4 ± 0.6 mm on Day 5, then decreased to 3.7 ± 0.5 mm on Day 7 and stabilised thereafter. FSH and oestradiol (E2) concentrations showed a distinct diurnal pattern; high at 7.00 a.m. and low at 3.00 p.m. E2 concentrations (7.00 a.m.) showed a 2.5-fold increase from Day –1 to Day 2, and subsequently a 2-fold decline to reach a plateau at Day 8. FSH concentrations reached maximum levels by Day 5 and slowly declined afterwards. In conclusion, once-daily administration of altrenogest starting one day before weaning delays the weaning-induced increase in LH pulses. Although FSH and follicle size increase until Day 5 after weaning, follicle E2 production already decreased from Day 2 after weaning. Post-weaning altrenogest treatment thus results in a follicular wave of follicles that lose oestrogenic competence at Day 2 after weaning, presumably related to the changed LH dynamics during altrenogest treatment.

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Influence of low amplitude/high frequency relative sea-level changes in a wave-dominated estuary (Miocene), São Luis Basin, northern Brazil

Sedimentary Geology ◽

10.1016/s0037-0738(00)00046-4 ◽

2000 ◽

Vol 133 (3-4) ◽

pp. 295-324 ◽

Cited By ~ 27

Author(s):

D de Fátima Rossetti

Keyword(s):

Sea Level ◽

High Frequency ◽

Sea Level Changes ◽

Relative Sea Level ◽

Northern Brazil ◽

Low Amplitude

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Upward shallowing platform cycles: A response to 2.2 billion years of low-amplitude, high-frequency (Milankovitch band) sea level oscillations

Paleoceanography ◽

10.1029/pa001i004p00403 ◽

1986 ◽

Vol 1 (4) ◽

pp. 403-416 ◽

Cited By ~ 31

Author(s):

J. P. Grotzinger

Keyword(s):

Sea Level ◽

High Frequency ◽

Sea Level Oscillations ◽

Low Amplitude

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Vibrational Fatigue Analysis of a Strain Loading Using the Frequency and Wavelet Filtering Methods

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.462-463.124 ◽

2011 ◽

Vol 462-463 ◽

pp. 124-129

Author(s):

Shahrum Abdullah ◽

Edisah Putra Teuku ◽

Zaki Nuawi Mohd. ◽

Mohd. Nopiah Zulkifli

Keyword(s):

High Frequency ◽

Filter Design ◽

High Amplitude ◽

Morlet Wavelet ◽

Wavelet Filtering ◽

Pass Filter ◽

Low Pass Filter ◽

Automotive Components ◽

Low Pass ◽

Low Amplitude

This paper presents a comparison work between the filtering methods of fatigue strain loadings using the frequency spectrum and the wavelet transform (WT), in which a raw loading signal can be simplified for purpose of simulation. For this reason, the Fast Fourier Transform (FFT) and the Morlet wavelet algorithms were used in order to transform the vibrational fatigue time series into the frequency domain signal, leading to the observation of the frequency characteristics of the signal. To retain high amplitude cycles in the FFT algorithm, a low pass filter technique was applied to remove the high frequency signals with small amplitude that are non-damaging. The departure of high frequency information smoothed the low amplitude cycles at high frequency events in the fatigue signal. The Butterworth filter was selected as the most efficient filter design as it retained most of the fatigue damage and also had the capability to remove 30 % of the original low amplitude cycles. On the other hand, the Morlet wavelet managed to remove 64 % of the original 59 second signal. This wavelet filtering method removed 34 % more than the similar procedure applied through the FFT approach. Hence, this fatigue data summarising algorithm can be used for studying the durability characteristics of automotive components.

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

Transactions of the ASABE ◽

10.13031/trans.14143 ◽

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.

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