Real-time sound speed correction using golden section search to enhance ultrasound imaging quality

2013 ◽  
Author(s):  
Chong Ook Yoon ◽  
Changhan Yoon ◽  
Yangmo Yoo ◽  
Tai-Kyong Song ◽  
Jin Ho Chang
2020 ◽  
Vol 142 (11) ◽  
Author(s):  
Julie K. Bothell ◽  
Timothy B. Morgan ◽  
Theodore J. Heindel

Abstract Optimization of jet engine sprays has the potential to improve efficiency and reduce environmental impact. Sprays can be continually optimized in multivariate scenarios using real-time feedback control, but a method of controlling the sprays based on physical properties must first be established. In this study, a spray controller was developed to optimize the spray angle obtained from shadowgraphs, with the assumption that the largest angle is desired. The spray angle was used as an example, as it is a physically important parameter which is easily found through shadowgraph imaging. Varying ratios of swirled air to straight air, determined by the image-based feedback controller were introduced into the air portion of a coaxial airblast nozzle while keeping the total air flow rate constant. A golden section search converged on the swirled air ratio that provided the largest angle and was validated from the distribution of spray angle versus swirled air ratio. The ratio that produced a spray with the greatest angle of 25.8 ± 2 deg was found at a swirled air ratio of 0.66 ± 0.03 for a spray with a momentum ratio of 6. The successful design and implementation of this image-based feedback controller is intended to provide a foundation for developing real-time active feedback controllers for sprays.


Author(s):  
Sagnik Pal ◽  
Ranjan Das

The present paper introduces an accurate numerical procedure to assess the internal thermal energy generation in an annular porous-finned heat sink from the sole assessment of surface temperature profile using the golden section search technique. All possible heat transfer modes and temperature dependence of all thermal parameters are accounted for in the present nonlinear model. At first, the direct problem is numerically solved using the Runge–Kutta method, whereas for predicting the prevailing heat generation within a given generalized fin domain an inverse method is used with the aid of the golden section search technique. After simplifications, the proposed scheme is credibly verified with other methodologies reported in the existing literature. Numerical predictions are performed under different levels of Gaussian noise from which accurate reconstructions are observed for measurement error up to 20%. The sensitivity study deciphers that the surface temperature field in itself is a strong function of the surface porosity, and the same is controlled through a joint trade-off among heat generation and other thermo-geometrical parameters. The present results acquired from the golden section search technique-assisted inverse method are proposed to be suitable for designing effective and robust porous fin heat sinks in order to deliver safe and enhanced heat transfer along with significant weight reduction with respect to the conventionally used systems. The present inverse estimation technique is proposed to be robust as it can be easily tailored to analyse all possible geometries manufactured from any material in a more accurate manner by taking into account all feasible heat transfer modes.


Ultrasonics ◽  
2015 ◽  
Vol 60 ◽  
pp. 6-10 ◽  
Author(s):  
Shiyue Sun ◽  
Dawei Wu ◽  
Benpeng Zhu ◽  
Yue Zhang ◽  
Shi Chen ◽  
...  

2015 ◽  
Vol 19 (2) ◽  
pp. 135-139 ◽  
Author(s):  
Antonio Corvino ◽  
Orlando Catalano ◽  
Fabio Corvino ◽  
Antonella Petrillo

2016 ◽  
Vol 63 (8) ◽  
pp. 1687-1698 ◽  
Author(s):  
Nima Akhlaghi ◽  
Clayton A. Baker ◽  
Mohamed Lahlou ◽  
Hozaifah Zafar ◽  
Karthik G. Murthy ◽  
...  

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