Condenser Tube Examination Using Acoustic Pulse Reflectometry

Author(s):  
N. Amir ◽  
O. Barzelay ◽  
A. Yefet ◽  
T. Pechter

Acoustic pulse reflectometry (APR) has been applied extensively to tubular systems in research laboratories for purposes of measuring input impedance, bore reconstruction, and fault detection. Industrial applications have been mentioned in the literature, though they have not been widely implemented. Academic APR systems are extremely bulky, often employing source tubes of 6 m in length, which limits their industrial use severely. Furthermore, leak detection methods described in the literature are based on indirect methods, by carrying out bore reconstruction and finding discrepancies between the expected and reconstructed bore. In this paper we describe an APR system designed specifically for detecting faults commonly found in industrial tube systems: leaks, increases in internal diameter caused by wall thinning, and constrictions. The system employs extremely short source tubes, in the order of 20 cm, making it extremely portable, but creating a large degree of overlap between forward and backward propagating waves in the system. A series of algorithmic innovations enable the system to perform the wave separation mathematically, and then identify the above faults automatically with a measurement time on the order of 10 s per tube. We present several case studies of condenser tube inspection, showing how different faults are identified and reported.

Author(s):  
Noam Amir ◽  
Oded Barzelay ◽  
Amir Yefet ◽  
Tal Pechter

Acoustic Pulse Reflectometry (APR) has been applied extensively to tubular systems in research laboratories, for purposes of measuring input impedance, bore reconstruction, and fault detection. Industrial applications have been mentioned in the literature, though they have not been widely implemented. Academic APR systems are extremely bulky, often employing source tubes of six meters in length, which limits their industrial use severely. Furthermore, leak detection methods described in the literature are based on indirect methods, by carrying out bore reconstruction and finding discrepancies between the expected and reconstructed bore. In this paper we describe an APR system designed specifically for detecting faults commonly found in industrial tube systems: leaks, increases in internal diameter caused by wall thinning, and constrictions. The system employs extremely short source tubes, on the order of 20cm, making it extremely portable, but creating a large degree of overlap between forward and backward propagating waves in the system. A series of algorithmic innovations enable the system to perform the wave separation mathematically, and then identify the above faults automatically, with a measurement time on the order of 10 seconds per tube. We present several case studies of condenser tube inspection, showing how different faults are identified and reported.


2020 ◽  
Vol 21 (13) ◽  
pp. 4574
Author(s):  
Elena Rosini ◽  
Paola D’Antona ◽  
Loredano Pollegioni

D-enantiomers of amino acids (D-AAs) are only present in low amounts in nature, frequently at trace levels, and for this reason, their biological function was undervalued for a long time. In the past 25 years, the improvements in analytical methods, such as gas chromatography, HPLC, and capillary electrophoresis, allowed to detect D-AAs in foodstuffs and biological samples and to attribute them specific biological functions in mammals. These methods are time-consuming, expensive, and not suitable for online application; however, life science investigations and industrial applications require rapid and selective determination of D-AAs, as only biosensors can offer. In the present review, we provide a status update concerning biosensors for detecting and quantifying D-AAs and their applications for safety and quality of foods, human health, and neurological research. The review reports the main challenges in the field, such as selectivity, in order to distinguish the different D-AAs present in a solution, the simultaneous assay of both L- and D-AAs, the production of implantable devices, and surface-scanning biosensors. These innovative tools will push future research aimed at investigating the neurological role of D-AAs, a vibrant field that is growing at an accelerating pace.


2014 ◽  
Vol 602-605 ◽  
pp. 1594-1597
Author(s):  
Han Xin Chen ◽  
Shi Qi Yang

This paper investigated the ultrasonic mechanism of Time of Flight Diffraction (TOFD) by finite element analysis for the better applications of ultrasonic TOFD (Time of Flight Diffraction) detection technology. The welding steel plate with the artificial defects is used in the finite element analysis model. The experimental A-scan signal with higher noise is filtered by the wavelet transform, which can clearly show defective diffracted wave. The software simulation of ultrasound is used to present the propagation process of ultrasonic signal inside the sample. Simulation results are compared with the experimental results, which shows valid basis for the practical TOFD ultrasonic detection methods in industrial applications.


Machines ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 10 ◽  
Author(s):  
Alessandro Palmieri ◽  
Renato Procopio ◽  
Andrea Bonfiglio ◽  
Massimo Brignone ◽  
Marco Invernizzi ◽  
...  

Model-based control techniques have been gaining more and more interest these days. These complex control systems are mostly based on theories, such as feedback linearization, model predictive control, adaptive and robust control. In this paper the latter approach is investigated, in particular, sliding mode (SM) control is analyzed. While several works on the description and application of SM control on single-input single-output systems can easily be found, its application on multi-input multi-output systems is not examined in depth at the same level. Hence, this work aims at formalizing some theoretical complements about the necessary conditions for the feasibility of the SM control for multi-input-multi-output systems. Furthermore, in order to obtain the desired performance from the control system, a method for parameter tuning is proposed in the particular case in which the relative degree of the controlled channels is equal to one. Finally, a simple control problem example is shown with the aim of stressing the benefits derived from the application of the theoretical complements described here.


2020 ◽  
Author(s):  
Miguel Angel Cabrera ◽  
Gustavo Pinzón

<p>The granular column collapse is a simplified system of the complex dynamics observed in gravity-driven natural mass-movements (i.e., landslides, debris flows, rock avalanches) and industrial applications (i.e., pharmaceutics, concrete, and food industry). In this system, a granular column is built with an initial height and initial width and then is allowed to collapse by self-weight onto a horizontal plane, while observing the variation in runout as a function of its initial geometry. Despite its wide use in the study of mass-movements mobility, either dry or with a liquid, little is known on the internal physics during collapse and its variation when immersed in an ambient fluid. This work presents a planar setup that allows the study of fully and partially immersed granular columns, with little disturbance at release [1]. The use of a planar configuration allows the monitoring of the moving mass and its deformation patterns, providing a unique insight into the particle-fluid interactions at release and during collapse that were not possible before. These observations are of great importance for the understanding of particle-fluid interactions at a mesoscale and can shed light into larger processes like a submarine and subaerial landslides. This work addresses these interactions by varying the geometry and measuring the mobility in dry and immersed conditions. The associated deformation patterns are observed both at the column-scale and at the particle-scale, reflecting in the velocity scaling of a deformable and moving granular mass and the occasional ejection of particles at its surface. We observed that the area of the released portion decreases during collapse and converges toward an equivalent portion of surface particles with little influence by the initial column geometry. These observations validate the planar setup for the study of granular columns, provides a novel interpretation in the momentum transfer in particle-fluid systems, and sets a validation case for future numerical simulations.</p><p>[1] Pinzon & Cabrera, Planar collapse of a submerged granular column. Physics of fluids, v31, 2019.</p>


Author(s):  
SAEID BELKASIM ◽  
XIANYU HONG ◽  
O. BASIR

Image retrieval plays an important role in a broad spectrum of applications. Contentbased retrieval (CBR) is one of the popular choices in many biomedical and industrial applications. Discrete image transforms have been widely studied and suggested for many image retrieval applications. The Discrete Wavelet Transform (DWT) is one of the most popular transforms recently applied to many image processing applications. The Daubechies wavelet can be used to form the basis for extracting features in retrieving images based on the description of a particular object within the scene. This wavelet is widely used for image compression. In this paper we highlight the common features between compression and retrieval. Several examples are used to test the DWT retrieval system. A comparison between DWT and Discrete Cosine Transform (DCT) is also made. The retrieval system using DWT requires preprocessing and normalization of images, which might slow down the retrieval process. The accuracy of the retrieval using DWT has been significantly improved by incorporating efficient K-Neighbor Nearest Distance (KNND) measure in our system.


2015 ◽  
Vol 36 (3) ◽  
pp. 49-59 ◽  
Author(s):  
Rafał Laskowski ◽  
Artur Rusowicz ◽  
Andrzej Grzebielec

Abstract The internal diameter of a tube in a ‘church window’ condenser was estimated using an entropy generation minimization approach. The adopted model took into account the entropy generation due to heat transfer and flow resistance from the cooling-water side. Calculations were performed considering two equations for the flow resistance coefficient for four different roughness values of a condenser tube. Following the analysis, the internal diameter of the tube was obtained in the range of 17.5 mm to 20 mm (the current internal diameter of the condenser tube is 22 mm). The calculated diameter depends on and is positively related to the roughness assumed in the model.


2019 ◽  
Author(s):  
Michael J. Capeness ◽  
Lisa Imrie ◽  
Lukas F. Mühlbauer ◽  
Thierry Le Bihan ◽  
Louise E. Horsfall

AbstractPlatinum and palladium are much sought-after metals of global critical importance in terms of abundance and availability. At the nano-scale these metals are of even higher value due to their catalytic abilities for industrial applications.Desulfovibrio alaskensisis able to capture ionic forms of both of these metals, reduce them, and synthesize elemental nanoparticles. Despite this ability very little is known about the biological pathways involved in the formation of these nanoparticles. Proteomic analysis ofD. alaskensisin response to platinum and palladium has highlighted those proteins involved in both the reductive pathways and the wider stress-response system. A core set of 13 proteins was found in both treatments and consisted of proteins involved in metal transport and reduction. There were also 7 proteins specific to either platinum or palladium. Over-expression of one of these platinum-specific genes, a NiFe hydrogenase small subunit (Dde_2137), resulted in the formation of larger nanoparticles. This study improves our understanding of the pathways involved in the metal resistance mechanism ofDesulfovibrioand informs how we can tailor the bacterium for nanoparticle production, enhancing its application as a bioremediation tool and as way to capture contaminant metals from the environment.ImportanceBacteria, in particularlyD. alaskensis, represent a biological and greener way to capture high value metals such as platinum group metals from environmental and industrial waste streams. The recovery of these metals in nanoparticle forms adds extra value to this process as they can be used in a variety of different industrial applications as they have exceptional catalytic capabilities.D. alaskensisability to do this, has been widely reported, though very little is understood about the underlying protein and genetic components. It is by understanding the biological basis of this capability that we can further improve and adapt this bacterium to be better at bioremediation and to control its ability to do so.


2019 ◽  
Vol 8 (4) ◽  
pp. 3841-3845 ◽  

Electro-hydraulic systems (EHS) are widely used in industrial applications due to the high-power density and accuracy. However, EHS are highly nonlinear which makes its modelling and control aspects a complex process. In this paper, we present the modelling and position control for an electro-hydraulic system (EHS). The mathematical modelling is carried out considering the non-linearities like friction, discharge coefficient and load mass present in the system. A back-stepping control scheme is developed for maintaining the accuracy in the position control. The closed-loop stability of the proposed control system is analyzed with Lyapunov’s theory. The performance of the control system under the effect of bounded external uncertainties is validated with simulation study. The study indicates that the proposed controller gives an effective motion control in presence of the system uncertainties.


Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5928
Author(s):  
Abbas Hasani ◽  
Claus Leth Bak ◽  
Filipe Miguel Faria da Silva

Loss of excitation (LOE) relay is one of the most essential protection elements for synchronous generators in power plants. During the last few decades, several LOE detection methods have been proposed, while limited schemes such as admittance- and impedance-based ones have been adopted for industrial applications. This study investigates and compares the behavior of some practical LOE detection schemes through extensive simulation scenarios, and from the reliability, speed, and security points of view. The simulation scenarios are accomplished by using the real-time-digital-simulator, where the phase domain model of the synchronous generator is used to develop a realistic and typical power generation system. Employing such a system, different types of complete and partial LOE incidents can be applied according to IEEE Standard C37.102-2006, while the performance of any scheme can be assessed through accurate and realistic LOE scenarios.


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