Ultrasonic techniques in industrial cleaning

1956 ◽  
Vol 35 (10) ◽  
pp. 619
Author(s):  
W. McCracken
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Muhammad Bilal ◽  
Hamna Arshad ◽  
Muhammad Ramzan ◽  
Zahir Shah ◽  
Poom Kumam

AbstractThe key objective of the present research is to examine the hybrid magnetohydrodynamics (MHD) nanofluid (Carbon-nanotubes and ferrous oxide–water) CNT–Fe3O4/H2 flow into a horizontal parallel channel with thermal radiation through squeezing and dilating porous walls. The parting motion is triggered by the porous walls of the channel. The fluid flow is time-dependent and laminar. The channel is asymmetric and the upper and lower walls are distinct in temperature and are porous. With the combination of nanoparticles of Fe3O4 and single and multi-wall carbon nanotubes, the hybrid nanofluid principle is exploited. By using the similarity transformation, the set of partial differential equations (PDEs) of this mathematical model, governed by momentum and energy equations, is reduced to corresponding ordinary differential equations (ODEs). A very simple numerical approach called the Runge–Kutta system of order four along with the shooting technique is used to achieve the solutions for regulating ODEs. MATLAB computing software is used to create temperature and velocity profile graphs for various emerging parameters. At the end of the manuscript, the main conclusions are summarized. Through different graphs, it is observed that hybrid-nanofluid has more prominent thermal enhancement than simple nanofluid. Further, the single-wall nanotubes have dominated impact on temperature than the multi-wall carbon nanotubes. From the calculations, it is also noted that Fe2O3–MWCNT–water has an average of 4.84% more rate of heat transfer than the Fe2O3–SWCNT–water. On the other hand, 8.27% more heat flow observed in Fe2O3–SWCNT–water than the simple nanofluid. Such study is very important in coolant circulation, inter-body fluid transportation, aerospace engineering, and industrial cleaning procedures, etc.


Mathematics ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 850
Author(s):  
Pietro Burrascano ◽  
Matteo Ciuffetti

Ultrasonic techniques are widely used for the detection of defects in solid structures. They are mainly based on estimating the impulse response of the system and most often refer to linear models. High-stress conditions of the structures may reveal non-linear aspects of their behavior caused by even small defects due to ageing or previous severe loading: consequently, models suitable to identify the existence of a non-linear input-output characteristic of the system allow to improve the sensitivity of the detection procedure, making it possible to observe the onset of fatigue-induced cracks and/or defects by highlighting the early stages of their formation. This paper starts from an analysis of the characteristics of a damage index that has proved effective for the early detection of defects based on their non-linear behavior: it is based on the Hammerstein model of the non-linear physical system. The availability of this mathematical model makes it possible to derive from it a number of different global parameters, all of which are suitable for highlighting the onset of defects in the structure under examination, but whose characteristics can be very different from each other. In this work, an original damage index based on the same Hammerstein model is proposed. We report the results of several experiments showing that our proposed damage index has a much higher sensitivity even for small defects. Moreover, extensive tests conducted in the presence of different levels of additive noise show that the new proposed estimator adds to this sensitivity feature a better estimation stability in the presence of additive noise.


Systems ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 6
Author(s):  
Khaled Medini ◽  
Sophie Peillon ◽  
Martha Orellano ◽  
Stefan Wiesner ◽  
Ang Liu

The evolution towards more customer-centric operations within manufacturing and service industries gave rise to novel ways of value creation and delivery such as Product–Service Systems (PSS). PSS integrate tangible and intangible elements to create new values for both customers and providers. Therefore, a close collaboration is required among various actors in a value network to co-create values towards win–win gains. For companies to keep up with this pace, new decision support tools are needed to accompany PSS engineering and to adjust business models. This need is confronted with the scarcity of PSS-oriented economic assessment models and methods. This paper presents a comprehensive framework for the economic assessment of PSS. The framework relies on a novel combination of system modelling and analysis approaches to enable cost and revenue attribution to different actors in a value network. The applicability and relevance of the framework are demonstrated through a case study in the industrial cleaning sector.


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