Tomography MCMC method exploration software package

Statistical methods such as Monte Carlo Markov Chain (MCMC) coupled with Bayesian approach proved its usefulness to the Electrical Capacitance Tomography (ECT) inverse problem solution. However, this methodology is very sensitive to the values of method parameters. The dedicated tool for investigation of this statistical method and for algorithm adjusting, testing, verification and optimization is proposed in the paper

SYMULACJA PRZEPŁYWU GRAWITACYJNEGO I ESTYMACJA JEGO PARAMETRÓW PRZY UŻYCIU ELEKTRYCZNEJ TOMOGRAFII POJEMNOŚCIOWEJ I SZTUCZNYCH SIECI NEURONOWYCH

The paper presents a new approach to monitoring changes of characteristic parameters of gravitational solids flow. Electrical Capacitance Tomography (ECT) is applied for non-invasive process monitoring. Artificial Neural Networks (ANN) are used to estimate important flow parameters knowing the measured capacitances. The proposed approach solves the ECT inverse problem in a direct manner and provides a rapid parameterization of the funnel flow. The simulation of the silo discharging process is performed relying on real flow behaviour obtained from the authors’ previous work. The simulated data are used to new approach testing and verification. The obtained results proved that proposed ANN-based method will allow for on-line gravitational solids flow monitoring.W artykule opisano nowe podejście do monitorowania zmian charakterystycznych parametrów przepływu grawitacyjnego. Do nieinwazyjnego monitorowania procesu stosowana jest Elektryczna Tomografia Pojemnościowa (ECT). Sztuczne Sieci Neuronowe wykorzystywane są do estymacji ważnych parametrów przepływu na podstawie mierzonych pojemności. Zaproponowane podejście pozwala na rozwiązanie problemu odwrotnego w ECT w sposób bezpośredni i umożliwia natychmiastową parametryzację przepływu kominowego. Symulacja procesu rozładowania silosu została wykonana na podstawie wyników wcześniejszych badań eksperymentalnych przeprowadzonych na rzeczywistym obiekcie. Dane symulacyjne wykorzystano do testowania i weryfikacji nowego podejścia. Uzyskane wyniki wykazały, iż zaproponowana metoda wykorzystująca Sztuczne Sieci Neuronowe pozwoli na monitorowanie on-line parametrów przepływu grawitacyjnego

METODY PARAMETRYCZNE W ROZWIĄZYWANIU PROBLEMU ODWROTNEGO DLA MONITOROWANIA PRZEPŁYWÓW MATERIAŁÓW SYPKICH

The article presents the parametrisation-based methods of monitoring of the process of gravitational silo discharging with aid of capacitance tomography techniques. Proposed methods cover probabilistic Bayes’ modelling, including spatial and temporal analysis and Markov chain Monte Carlo methods as well as process parametrisation with artificial neural networks. In contrast to classical image reconstruction-based methods, parametric modelling allows to omit this stage as well as abandon the associated reconstruction errors. Parametric modelling enables the direct analysis of significant parameters of investigated process that in turn results in easier incorporation into the control feedback loop. Presented examples are given for the gravitational flow of bulk solids in silos.Niniejszy artykuł przedstawia parametryczne metody rozwiązywania problemu odwrotnego w tomografii pojemnościowej na przykładzie monitorowania procesu przepływu materiałów sypkich przy użyciu tomografii pojemnościowej. Wybrane metody obejmują modelowanie probabilistyczne Bayesa, w tym przestrzenne i czasowe oraz metody Monte Carlo łańcuchów Markowa, a także parametryzację procesu z użyciem sztucznych sieci neuronowych. W odróżnieniu od klasycznych metod opartych na algorytmach rekonstrukcji obrazu parametryzacja pozwala na pominięcie tego etapu, a co za tym idzie brak dodatkowych błędów związanych z rekonstrukcją. Parametryzacja pozwala na bezpośrednią analizę istotnych parametrów badanego procesu, przez co łatwiejsze jest użycie tych wyników w pętli sprzężenia zwrotnego sterowania. Przykłady rozpatrywane w tekście są opisane dla procesu grawitacyjnego opróżniania materiałów sypkich przechowywanych w silosach

Measurement of dynamic pulsations in bulk solid during silo discharging using ECT method

Paper will focus on the results of tests with the slender cylindrical silo emptied both gravitationally and in controlled manner. The influence of the initial density, wall roughness, height and velocity on the emptying process will be presented. During tests values of the vertical and horizontal accelerations on the silo wall were measured, the effect of the outlet velocity and level of the dynamic effects were compared. Results will be presented in the form of continuous graphs, which allow to analyse the entire process in simpler way comparing to tomographic images form. It is a better form of presentation in order to work out settings for process control, as well

WYZNACZANIE PRĘDKOŚCI PRZEPŁYWY KORKOWEGO W TRANSPORCIE PNEUMATYCZNYM MATERIAŁU SYPKIEGO W OPARCIU O TECHNIKI PRZETWARZANIA OBRAZÓW

The article presents the use of fast cameras and image processing and analysis methods to determine the velocity of pneumatic transport of bulk material. The presented solution is dedicated to the analysis of dense flow in the form of slugs moving in a horizontal section of the pipeline. The developed image-processing algorithm is based on the estimation of the bulk solid material level in the pipeline in particular moments of the process. The acquisition of an image containing the area of two separate sections of the pipeline allows to determine the shift-time of material between two pre-defined pipeline regions. The obtained results indicate the proper action of the developed systemW artykule przedstawiono zastosowanie szybkich kamer oraz metod przetwarzania i analizy obrazów do wyznaczenia prędkości transportu pneumatycznego materiału sypkiego. Przedstawione rozwiązanie dedykowane jest analizie zmian prędkości przepływu gęstego w formie korków przemieszczających się w poziomym odcinku rurociągu. Opracowany algorytmy przetwarzania obrazów opiera się na wyznaczeniu poziomu wypełnienia rurociągu materiałem sypkim w poszczególnych chwilach trwania procesu. Akwizycja obrazu zawierającego obszar dwóch oddzielnych sekcji rurociągu pozwoliła na określenie czasu przejścia materiału między oboma, pre-definiowanymi, obszarami rurociągu. Uzyskane wyniki wskazują na poprawne działanie opracowanego systemu

Longitudinal assessment of renal size and function in extremely low birth weight children at 7 and 11 years of age

BACKGROUND: There are a lack of studies describing a longitudinal association between preterm delivery and renal complications later in life. We assessed renal size and function in preterm infants born with extremely low birth weight (ELBW) during 4 years of follow-up, comparing these parameters to age-matched children born full term (term controls). METHODS: The results of selected renal laboratory tests [levels of cystatin C, creatinine, blood urea nitrogen (BUN)] and of renal ultrasound evaluations were compared between the ELBW group and the term control group at age 7 and 11 years. RESULTS: The study population consisted of 64 children born with ELBW (ELBW children) who had been recruited at birth and 36 children born at term (term children) who took part in both follow-up assessments. Renal ultrasound examination revealed a significantly smaller renal volume in the 7- and 11-year-old ELBW children compared to the term controls [right kidney volume: 50.8 vs. 61.2 ml/m(2), respectively, at 7 years (p <0.01) and 51.4 vs. 58.2 ml/m(2), respectively, at 11 years (p <0.01); left kidney volume: 51.4 vs. 60.3 ml/m(2), respectively, at 7 years (p <0.01) and 55.2 vs. 60.7 ml/m(2), respectively, at 11 years (p = 0.02)]. Renal function in ELBW children was also affected. Serum cystatin C levels were significantly higher in ELBW children than in the controls at 7 years of age, and this difference remained statistically significant at 11 years of age [0.63 vs. 0.59 mg/l, respectively, at 7 years (p = 0.02) and 0.72 vs. 0.61 mg/l, respectively, at 11 years (p = 0.01)]. Six ELBW children also had elevated cystatin C levels (0.97–1.11 mg/l) at 11 years of age. Cystatin C levels were within normal range in the ELBW children at age 7 years and in term children in both follow-up studies. BUN levels were higher in ELBW children at the age of 11 years (4.49 vs. 4.15 mmol/l; p = 0.028). CONCLUSION: Continued follow-up of these patients will reveal whether the observed worsening in renal function will persist into adulthood

Blood pressure profile in the 7th and 11th year of life in children born prematurely

BACKGROUND: Several research trials have analyzed the impact of prematurity on the prevalence of hypertension (HT). However, prospective long-term studies are lacking. OBJECTIVES: The aim of this study was to evaluate the prevalence of HT at the age of 7 and 11 years in a regional cohort of preterm infants with a birth weight of ≤ 1000 g. PATIENTS AND METHODS: This study included 67 children with a birth weight of ≤ 1000 g who were born in Malopolska between September 2002 and August 2004. The control group consisted of 38 children born at term, matched for age. Each child underwent 24-h ambulatory blood pressure measurement (ABPM) twice, once at the age of 7 and again at 11 years. The presence of HT was estimated according to the mean arterial pressure (MAP) and a number of individual measurements. RESULTS: At aged 7 years, preterm infants had a significantly higher incidence of HT, defined on the basis of MAP (15% vs. 0%; P < 0.02) and on the percent of individual measurements (56% vs. 33%, P < 0.036). After taking into account the group of patients who received anti-HT treatment after the first part of the study, the incidence of HT at the age of 11 years based on MAP was 19% vs. 10%. Based on the individual measurements, it was 36.5% in the preterm infants vs. 24% in the control group. The differences were not statistically significant. At both time points, the preterm group had a higher mean heart rate (HR) than the control group. CONCLUSIONS: Children born prematurely are predisposed to HT in later life, in addition to the persistence of an increased HR

Monitoring of solids behaviour during gravitional flow in rectangular silo

This paper is focused on the application of Electrical Capacitance Tomography (ECT) to gravitational flow of bulk solid in rectangular silo investigation. In order to measure the materials distribution inside a vessel, a dedicated, spatial 16 electrode sensor is designed. Reconstructed images are presented in 3D domain space. The investigated silo model consists of rectangular bin and a cone-like hopper section. The flow behaviour of material (friable sand) is studied for two silo model configurations having different lower section slopes. The slope angle is a silo geometrical parameter affecting the type of the flow regime - mass or funnel type