scholarly journals Transfer coupler reciprocity method for the absolute low‐frequency calibration of field hydrophones under full environmental conditions

1995 ◽  
Vol 98 (5) ◽  
pp. 2980-2980
Author(s):  
Joseph F. Zalesak
Keyword(s):  
Environmental Conditions ◽  
Low Frequency ◽  
Reciprocity Method ◽  
The Absolute ◽  
Frequency Calibration

Low-frequency calibration of a multidimensional acoustic intensity probe for application to rocket noise

2011 ◽  
Vol 130 (4) ◽  
pp. 2512-2512
Author(s):  
Jarom H. Giraud ◽  
Kent L. Gee ◽  
Scott D. Sommerfeldt ◽  
R. Troy Taylor ◽  
Jonathan D. Blotter
Keyword(s):  
Low Frequency ◽  
Acoustic Intensity ◽  
Frequency Calibration

A modified electro-acoustical reciprocity method for measuring low-frequency sound source in arbitrary surroundings

2017 ◽  
Vol 116 ◽  
pp. 1-8 ◽  
Author(s):  
Ling Lu ◽  
Hongling Sun ◽  
Ming Wu ◽  
Qiaoxi Zhu ◽  
Jun Yang
Keyword(s):  
Sound Source ◽  
Low Frequency ◽  
Frequency Sound ◽  
Reciprocity Method

scholarly journals Read Range Optimization of Low Frequency RFID System in Hostile Environmental Conditions by Using RSM Approach

Evergreen ◽  
2020 ◽  
Vol 7 (3) ◽  
pp. 396-403
Author(s):  
Shilpa Choudhary ◽  
Abhishek Sharma ◽  
Kashish Srivastava ◽  
Hemant Purohit ◽  
Mudita Vats
Keyword(s):  
Environmental Conditions ◽  
Low Frequency ◽  
Rfid System ◽  
Read Range

scholarly journals Environmental Conditions Modulating Tropical Cyclone Formation over the Bay of Bengal during the Pre-Monsoon Transition Period

2019 ◽  
Vol 32 (14) ◽  
pp. 4387-4394
Author(s):  
Zhi Li ◽  
Weidong Yu ◽  
Kuiping Li ◽  
Huiwu Wang ◽  
Yanliang Liu
Keyword(s):  
Bay Of Bengal ◽  
Environmental Conditions ◽  
Transition Period ◽  
Formation Rate ◽  
Low Frequency ◽  
Vertical Wind Shear ◽  
Specific Humidity ◽  
Positive Contribution ◽  
Air Temperatures ◽  
Significant Difference

Abstract Globally, the highest formation rate of super tropical cyclones (TCs) occurs over the Bay of Bengal (BoB) during the premonsoon transition period (PMT), but TC genesis has a low frequency here. TCs have occurred over the BoB in only 20 of the past 36 years of PMTs (1981–2016). This study investigates which environmental conditions modulate TC formation during the PMT over the BoB by conducting a quantitative analysis based on the genesis potential parameter, vorticity tendency equation, and specific humidity budget equation. The results show that there is a cyclonic anomaly in the TC genesis group compared to the non-TC genesis group, which is mainly due to the divergence term. A significant difference in vorticity contributes to TC formation over the BoB during the PMT. Furthermore, anomalous cyclonic flow enhances ascending motion, transporting moisture to the midlevel atmosphere. A change in specific humidity (SH) causes an increase in relative humidity, which contributes positively to TC formation. The vertical wind shear also makes a small positive contribution. In contrast to the previous three terms, the contribution from the instability term associated with 500- and 850-hPa air temperatures is negative and almost negligible. In addition, the synoptic-scale disturbance energy is more powerful in the TC genesis group than in the non-TC genesis group, which is favorable for TC breeding. Together, these conditions determine whether TCs are generated over the BoB during the PMT.

Low Frequency Calibration of Measurement Microphones

Noise Notes ◽  
2010 ◽  
Vol 9 (2) ◽  
pp. 55-60
Author(s):  
Gunnar Rasmussen ◽  
Kim Nielson
Keyword(s):  
Low Frequency ◽  
Frequency Calibration

High-precision and low-cost vibration generator for low-frequency calibration system

2018 ◽  
Vol 29 (3) ◽  
pp. 034008 ◽  
Author(s):  
Rui-Jun Li ◽  
Ying-Jun Lei ◽  
Lian-Sheng Zhang ◽  
Zhen-Xin Chang ◽  
Kuang-Chao Fan ◽  
...  
Keyword(s):  
High Precision ◽  
Low Cost ◽  
Low Frequency ◽  
Calibration System ◽  
Frequency Calibration

Low Frequency Calibration of Measurement Microphones

2009 ◽  
Vol 28 (3) ◽  
pp. 223-228 ◽  
Author(s):  
Gunnar Rasmussen ◽  
Kim M. Nielson
Keyword(s):  
Frequency Response ◽  
Sound Pressure ◽  
Low Frequency ◽  
Constant Force ◽  
Low Frequencies ◽  
Proportional Relation ◽  
Frequency Calibration ◽  
Large Piston

The calibration of measurement microphones below 100 Hz is not very well covered by the present IEC standards. The uncertainty increases rapidly and for very low frequencies it goes toward infinity. This paper approaches this issue and presents a unique way to verifying and calibrating the low-frequency response of measurement microphones. Using a small isolated calibration volume and applying a constant force to a large piston inside this volume, you obtain a direct proportional relation between force and sound pressure, allowing calibration of measurement microphones down to 0.01 Hz.

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