Piezoelectric and optical setup to measure an electrical field: Application to the longitudinal near-field generated by a tapered coax

ABSTRACTWe propose multi-layer near-field recording with using inner focus mode. The restricted conditions for multi-layer near-field recording are discussed from the viewpoint of both media structure and optical setup. One solution is presented for dual layer recording with a numerical aperture (NA) of 1.5 and a wavelength of 405 nm as a light source of GaN laser diode.In the proposed layer structure, a Nb2O5 material has been adopted as the intermediate layer because of its high refractive index, n = 2.4, in order to prevent the decrease of beam propagation that corresponds to NA>1. Almost the same signal characteristics can be obtained from both recording layers at the air gap of 40 nm. The adjustment of focusing position and the compensation of spherical aberrations have been implemented by the combination of an expander lens unit and a liquid crystal (LC) panel in the optical setup.

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1-Dimensional quantitative micro-architecture mapping of multiple scattering media using backscattering of ultrasound in the near-field: Application to nodule imaging in the lungs

Applied Physics Letters ◽

10.1063/1.5038005 ◽

2018 ◽

Vol 113 (3) ◽

pp. 033704 ◽

Cited By ~ 5

Author(s):

Kaustav Mohanty ◽

John Blackwell ◽

S. Behrooz Masuodi ◽

Mir Hasnain Ali ◽

Thomas Egan ◽

...

Keyword(s):

Multiple Scattering ◽

Near Field ◽

Field Application ◽

Scattering Media

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Radiation properties of the semi-infinite vortex sheet

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1972.0139 ◽

1972 ◽

Vol 330 (1581) ◽

pp. 185-198 ◽

Cited By ~ 19

Keyword(s):

Acoustic Radiation ◽

Near Field ◽

Infinite Plate ◽

Sound Field ◽

Vortex Sheet ◽

Field Application ◽

Kutta Condition ◽

Radiation Properties ◽

Loading Effects ◽

Dependent Flow

An exact calculation is given of the acoustic radiation from a time dependent flow coupled to an inhomogeneous solid surface. Specifically, the flow consists of a vortex sheet leaving a semi-infinite plate and undergoing a two-dimensional spatial Kelvin-Helmholtz instability. In the absence of the plate, such an instability mode of the vortex sheet generates no sound. In the presence of a rigid plate, it is found that the intensity-directivity law is I ~ U 4 sin 2 1/2 θ , with θ measured from the downstream direction. If the plate is compliant and fluid loading effects high, the radiation is weaker, with I ~ U 5 sin 2 θ . These results agree completely with those predicted from general theories of the scattering of the near-field of point quadrupoles by large wedge-shaped surfaces (Ffowcs Williams & Hall 1970; Crighton & Leppington 1970, 1971). Imposition of the ‘rectified’ Kutta condition of Orszag & Crow (1970) does not modify the sound field. Application of the ‘full’ Kutta condition, that the sheet leaves the plate at zero gradient, results in an enormous increase in the radiation, with I ~ U 2 cosec 2 1/2 θ .

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Role of a corona field application in the physicochemical properties of stored strawberries

Research in Agricultural Engineering ◽

10.17221/50/2020-rae ◽

2021 ◽

Author(s):

Ali Esehaghbeygi ◽

Arash Hajisadeghian ◽

Masih Nasri Nasrabadi

Keyword(s):

Electric Field ◽

Botrytis Cinerea ◽

Colour Change ◽

Titratable Acidity ◽

Field Application ◽

Soluble Solids ◽

Postharvest Disease ◽

Lower Mass ◽

Electrical Field ◽

Mean Values

Grey mould disease caused by the fungus Botrytis cinerea Pers is widely distributed on strawberries as the dominant postharvest disease. Therefore, fruits have been treated using a pin-to-plate corona electrical field at a high voltage electric field (HVEF) intensity of 3.61, 4.56, and 5.13 kV·cm–1 for 60 minutes. The result revealed that the corona discharge demolished the B. cinerea growth using 20 kV·cm–1 for 10 min in the Petri dishes. In addition, the treated strawberries at 4.56 kV·cm–1 had an average infection rate of 23.33% compared with non-treated samples rate of 45.33%. The HVEF-treated samples showed significantly lower mass losses. The analysis of variance showed that the HVEF did not significantly affect the total soluble solids content, pH, titratable acidity, and softness; however, the lower acidity affected the Botrytis cinerea growth. No significant differences were observed among the mean values in the colour change parameters and colour difference for 4.56 kV·cm–1 compared with the control, while the lightness was significantly higher. The result show that the corona electrical field was able to demolish the B. cinerea growth, and an electric field intensity at 4.56 kV·cm–1 was found to extend the strawberries' cold storage and to lead to a lower mass loss.

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