In the paper is presented methodology of the X-ray image processing application to investigate gravitational flow in rectangular silo model. The proposed normalization procedure of X-ray data allows to visualize the changes of the volume fraction of sand during silo discharging process. The applied procedure of image processing, in contrast to the previously author works, allows to obtained more accurate information about the changes of material distribution level during process. The conducted image analysis simplifies the investigation of mass flow in various area of silo. The obtained results show the different particle behaviour in centre and at silo wall area. The experiments were conducted for different initially level of sand densities and roughness of the silo wall. Visualization of dissimilarity in interaction between the particles and particles, and between particles and the silo walls, even for smooth wall, was the main result of the Xray image analysis, especially for shear zone visualization.
Selam Waktola, Krzysztof Grudzien and Laurent Babout
The paper presents an automatic point set extraction method for reconstructing 3D tomography images of funnel flow boundary. The method clearly shows the boundary between the funnel flow and stagnant zone during silo discharging process. After adjusting the contrast of the original X-ray CT image and applying filter function, the intensity profile of the image shows a high jump corresponding to the local flow boundary position at a specific height of the silo model. By extracting and connecting those jump points gave us a boundary line of the funnel flow from the stagnant. The outcome of segmented image opens a door for analysing further about funnel flow in 3D images.
Selam Waktola, Laurent Babout and Krzysztof Grudzien
The paper presents an automatic method for segmenting 3D tomography images of a funnel flow area, during silo emptying process. For generating 3D images the silo model was scanned using X-ray Computed Tomography (CT) system. The method has been applied for a chosen single slice from 3D image. The image segmentation is based on the variance of pixels calculation in defined interrogation window (or kernel). The analysis of Signalto- Noise-Ratio (SNR) of the given image allows to improve the contrast in the image and facilitate the detection the boundary between funnel area and stagnant zone. The obtained results of image segmentation show a high potential in the silo flow investigation using in-situ experiment using X-ray visualization. Additionally, the study indicates that, the separation of the silo area into the funnel and stagnant zone parts is a very challenging task especially for the top and bottom area of silo where the contrast is the smallest.
Przemysław Kucharski, Andrzej Romanowski, Krzysztof Grudzień, Laurent Babout and Paweł Woźniak
We present TomoTable—a research prototype of a position sensing device hidden inside an ordinary table. While the Human-Computer Interaction (HCI) field has extensively explored possibilities for spatially-aware multi-device interactions, the sensing methods that would enable such systems are still complex and hard to deploy in the wild. TomoTable presents a possibility of easily deployable invisible positional sensing that uses electrical capacitance tomography (ECT). Electrodes are embedded inside the table structure and provide accurate imaging of what is placed on the table. The entire system is invisible to the user. Objects can be identified based on their electrical properties. Our work creates opportunities for in-the-wild studies using multi-device systems. In this paper, we share the technical concept of TomoTable, preliminary insights on its use and perspectives for future studies.
Agnieszka Leszczyńska, Aleksandra Kowalska, Krzysztof Grudzień, Andrzej Romanowski and Dominik Sankowski
The control of dense phase pneumatic convening process is not a trivial task. The control of bulk solids flow phenomena requires detailed knowledge about the temporal and spatial changes of material concentration during flow. This paper describes application of electrical capacitance tomography for the characterization of the pneumatic conveying of solids. The level of concentration changes obtained with the aid of tomography imaging and calculated flow velocity allows monitoring flow behaviour during the granular material transport process. The cross-correlation technique applied for image processing as well as the calculated pixels-based flow velocity profile together with the proposed visualisation method of tomography images sequence provide information about flow conditions. The study of flow characterization, based on ECT data, was conducted for measurements gathered with different flow conditions, including flow blockage.
Krzysztof Grudzień and Manuel Hernandez De La Torre Gonzalez
This paper presents a method for the investigations of the gravity flow of granular materials based on the analysis of CT images. The system of X-ray tomography allows to visualize the distribution of bulk material inside the silo model. The images of the distribution of the concentration of the material, both in the form of 3D tomography images and 2D radiographic images, allow to track the behaviour of the material during the silo discharging process. Application of image processing and analysis provides an in-depth tool for investigation of the flow. The proposed, in the paper, methodology of the tracer particles allow to track the particles position changes during the gravitational flow in silo. The determination of tracer particles position is based on the vision information stored in volumetric computed tomography images and two-dimensional radiography.
Andrzej Romanowski, Robert Nowotniak, Kacper Kawecki, Tomasz Jaworski, Zbigniew Chaniecki and Krzysztof Grudzień
This paper contain study of three algorithms for optimisation of use of materials for cutting process. Cutting Stock Problem (CSP) and one dimensional guillotine cat variant of the CSP is introduced. Afterwards three different way of solving the problem are presented. For each of theme one algorithm is proposed. First is creating all the possible solutions and choosing the best one. Second is trying to recreate a human thinking process by using a heuristic search. Third one is inspired by an evolution process in the nature. Design and implementation of each of them is presented. Proposed algorithms are tested and compared to each other and also to the other known solutions.
Zbigniew Chaniecki, Krzysztof Grudzień, Tomasz Jaworski, Grzegorz Rybak, Andrzej Romanowski and Dominik Sankowski
The paper presents results of the scale-up silo flow investigation in based on accelerometer signal analysis and Wi-Fi transmission, performed in distributed laboratory environment. Prepared, by the authors, a set of 8 accelerometers allows to measure a three-dimensional acceleration vector. The accelerometers were located outside silo, on its perimeter. The accelerometers signal changes allowed to analyze dynamic behavior of solid (vibrations/pulsations) at silo wall during discharging process. These dynamic effects are caused by stick-slip friction between the wall and the granular material. Information about the material pulsations and vibrations is crucial for monitoring the interaction between silo construction and particle during flow. Additionally such spatial position of accelerometers sensor allowed to collect information about nonsymmetrical flow inside silo.
Selam Waktola, Andre Bieberle, Frank Barthel, Martina Bieberle, Uwe Hampel, Krzysztof Grudzień and Laurent Babout
This paper presents an application of an ultrafast electron beam X-ray CT scanner for investigating the gravitational flow behavior of granulates through cylindrical silo model. The CT scanner allows obtaining crosssectional images of the granular material distribution with a spatial resolution of approximately 1 mm and a time resolution of 2 kHz. In order to conduct a deep analysis of the granular flow concentration changes, two image processing algorithm steps were applied. The first step deals with preprocessing and re-centering stacks of raw images. The second step divides the preprocessed image into several concentric rings and calculates the mean value to study radial concentration changes. Independent analysis of granular concentration in each ring provides useful knowledge to study the silo discharging during mass flow and funnel flow.
Krzysztof Grudzień, Zbigniew Chaniecki, Bartosz Matusiak, Andrzej Romanowski, Grzegorz Rybak and Dominik Sankowski
Measuring changes of bulk materials concentration during gravitational flow, a silo emptying is essential information for the assessment of the behaviour and condition of the material during the emptying of the silo. Parameters obtained during this process are important both in terms of process economics and safety, are the basis for monitoring and diagnostics of the process. Affect the current process, but primarily are the result of their filling the silo, and the process of storing the material. Previous studies, conducted by a team of authors, the laboratory-scale silos and numerical calculations and simulations of its increase, helped build the ECT sensor on a large scale. Results related to the change of scale of the sensor and the actual measurements will be discussed in the article. Proposed by the authors of the paper, the method of visualization, performed in the measuring process, helps to ask about the process and suggests a methodology for dealing with the material stored in the silo.