Research on Non-destructive test of porous ceramic insulation material for spacecraft based on Terahertz continuous wave imaging technology

Plane Wave Imaging (PWI) has been recently proposed for fast ultrasound inspections in the Non-Destructive-Testing (NDT) field. By using a single (or a reduced number) of plane wave emissions and parallel beamforming in reception, frame rates of hundreds to thousands of images per second can be achieved without significant image quality losses with regard to the Total Focusing Method (TFM) or Phased Array (PA). This work addresses the problem of applying PWI in the presence of arbitrarily shaped interfaces, which is a common problem in NDT. First, the mathematical formulation for generating a plane wave inside a component of arbitrary geometry is given, and the characteristics of the resultant acoustic field are analyzed by simulation, showing plane wavefronts with non-uniform amplitude. Then, an imaging strategy is proposed, accounting for this amplitude effect. Finally, the proposed method is experimentally validated, and its application limits are discussed.

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Micro Non-Uniform Linear Array (MNULA) for Ultrasound Plane Wave Imaging

Sensors ◽

10.3390/s21020640 ◽

2021 ◽

Vol 21 (2) ◽

pp. 640

Author(s):

Yujia Tang ◽

Zhangjian Li ◽

Yaoyao Cui ◽

Chen Yang ◽

Jiabing Lv ◽

...

Keyword(s):

Plane Wave ◽

Linear Array ◽

Near Field ◽

Uniform Linear Array ◽

Imaging Technology ◽

Linear Arrays ◽

Imaging Quality ◽

Imaging Results ◽

Wave Imaging ◽

Laboratory Technology

Ultrasound plane wave imaging technology has been applied to more clinical situations than ever before because of its rapid imaging speed and stable imaging quality. Most transducers used in plane wave imaging are linear arrays, but their structures limit the application of plane wave imaging technology in some special clinical situations, especially in the endoscopic environment. In the endoscopic environment, the size of the linear array transducer is strictly miniaturized, and the imaging range is also limited to the near field. Meanwhile, the near field of a micro linear array has serious mutual interferences between elements, which is against the imaging quality of near field. Therefore, we propose a new structure of a micro ultrasound linear array for plane wave imaging. In this paper, a theoretical comparison is given through sound field and imaging simulations. On the basis of primary work and laboratory technology, micro uniform and non-uniform linear arrays were made and experimented with the phantom setting. We selected appropriate evaluation parameters to verify the imaging results. Finally, we concluded that the micro non-uniform linear array eliminated the artifacts better than the micro uniform linear array without the additional use of signal processing methods, especially for target points in the near-field. We believe this study provides a possible solution for plane wave imaging in cramped environments like endoscopy.

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Experimental mix design approach of reactive powder concrete to recognize compressive strength through non-destructive test

Journal of Physics Conference Series ◽

10.1088/1742-6596/1913/1/012149 ◽

2021 ◽

Vol 1913 (1) ◽

pp. 012149

Author(s):

Hemantkumar G Sonkusare ◽

Prashant Y Pawade ◽

Hardik P Pujara

Keyword(s):

Compressive Strength ◽

Design Approach ◽

Mix Design ◽

Reactive Powder Concrete ◽

Destructive Test ◽

Reactive Powder ◽

Non Destructive

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Roadmap of Terahertz Imaging 2021

Sensors ◽

10.3390/s21124092 ◽

2021 ◽

Vol 21 (12) ◽

pp. 4092

Author(s):

Gintaras Valušis ◽

Alvydas Lisauskas ◽

Hui Yuan ◽

Wojciech Knap ◽

Hartmut G. Roskos

Keyword(s):

Room Temperature ◽

Continuous Wave ◽

Computational Imaging ◽

Imaging Systems ◽

Thz Imaging ◽

Operational Conditions ◽

Frequency Combs ◽

Wave Imaging ◽

On Chip ◽

Nano Imaging

In this roadmap article, we have focused on the most recent advances in terahertz (THz) imaging with particular attention paid to the optimization and miniaturization of the THz imaging systems. Such systems entail enhanced functionality, reduced power consumption, and increased convenience, thus being geared toward the implementation of THz imaging systems in real operational conditions. The article will touch upon the advanced solid-state-based THz imaging systems, including room temperature THz sensors and arrays, as well as their on-chip integration with diffractive THz optical components. We will cover the current-state of compact room temperature THz emission sources, both optolectronic and electrically driven; particular emphasis is attributed to the beam-forming role in THz imaging, THz holography and spatial filtering, THz nano-imaging, and computational imaging. A number of advanced THz techniques, such as light-field THz imaging, homodyne spectroscopy, and phase sensitive spectrometry, THz modulated continuous wave imaging, room temperature THz frequency combs, and passive THz imaging, as well as the use of artificial intelligence in THz data processing and optics development, will be reviewed. This roadmap presents a structured snapshot of current advances in THz imaging as of 2021 and provides an opinion on contemporary scientific and technological challenges in this field, as well as extrapolations of possible further evolution in THz imaging.

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