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1

Numerical investigation on the nanofluids heat transfer inside a porous inclined cavity with wavy boundary

Karimi B., Pirmohammadi M., Salehi-Shabestari A.

Archives of Mechanics

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2020

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Vol. 72, nr 6

511--524

EN

In the present work, a numerical study on the free-convective heat transfer in a porous media cavity with a wavy boundary was carried out. The validation was done by comparing the results with the experimental data. The cavity inclination angle, material of nanofluid, nanoparticles volume fraction, the Rayleigh number, and porosity of the medium are the parameters which are investigated in this study. Results suggested that, due to the thermophysical properties of Cu particles in water, the heat transfer rate was increased for Cu-Water nanofluid in comparison to Al2O3-Water nanofluid, while the heat transfer rate decreased by increasing the volume fraction of nanoparticles. Numerical results showed that the Rayleigh number has significant effect on the heat transfer rate so that increase in the Rayleigh number from 100 to 10 000 increased the averaged Nusselt number between 2 to 3 times. The effect of porosity on heat transfer proved that the convective heat transfer rate increased with increasing the porosity of the porous medium. The effect of inclination angle of cavity on the heat transfer rate suggested that the optimum angle of cavity causing the highest heat transfer rate from wavy wall is 45°.

2

A novel approach for automatic detection and classification of suspicious lesions in breast ultrasound images

Karimi B., Krzyżak A.

Journal of Artificial Intelligence and Soft Computing Research

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2013

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Vol. 3, No. 4

265--276

EN

In this research, a new method for automatic detection and classification of suspected breast cancer lesions using ultrasound images is proposed. In this fully automated method, de-noising using fuzzy logic and correlation among ultrasound images taken from different angles is used. Feature selection using combination of sequential backward search, sequential forward search and distance-based methods is obtained. A new segmentation method based on automatic selection of seed points and region growing is proposed and classification of lesions into two malignant and benign classes using combination of AdaBoost, Artificial Neural Network and Fuzzy Support Vector Machine classifiers and majority voting is implemented.

3

Optimal open pit mining equipment selection using fuzzy multiple attribute decision making approach

Bazzazi A. A., Osanloo M., Karimi B.

Archives of Mining Sciences

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2009

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Vol. 54, no 2

301-320

EN

Equipment selection in mining engineering is one of the most important decision that is affected the mine design, production planning and economic parameters in open pit mining. Mine planning engineers generally use of their intuition and experiences in decision making even though equipment selection is a complex multi criteria decision problem. In real-world situation, because of incomplete or non-obtainable information, the data (attributes) are often not so deterministic; therefore they usually are fuzzy-imprecise. Combination of Analytical Hierarchy process (AHP) and entropy method applied to calculate global weights of the attributes. The weights then passed to the Technique for Order Preference Similarity to Ideal Solution (TOPSIS) method that the most efficient mining equipment alternative(s) could be appointed through distance measurement so that the best alternative has the nearest (distance) to the ideal solution and farthest from the negative-ideal solution in fuzzy environment. This approach is applied to select optimal loading-haulage equipment in Sungun open pit mine of Iran.

PL

Odpowiedni dobór urządzeń górniczych jest jedną z najważniejszych decyzji przy projektowaniu kopalń, planowaniu produkcji i przy analizie parametrów ekonomicznych funkcjonowania kopalni odkrywkowej. Inżynierowie odpowiedzialni za projektowanie kopalń przy podejmowaniu decyzji zazwyczaj bazują na własnej intuicji i doświadczeniu, mimo że dobór wyposażenia jest złożonym zagadnieniem wielokryterialnym. W rzeczywistych sytuacjach, z uwagi na brak wszelkich niezbędnych informacji, dane (cechy) nie zawsze są jasno określone, niejednokrotnie są one nieprecyzyjne, rozmyte. Metoda zwana AHP (Analytical Hierarchy Process) w połączeniu z metodą entropii wykorzystana została do obliczenia współczynników wagi poszczególnych atrybutów (cech). Następnie wagi te zastosowano w metodzie TOPSIS, oznaczającej poszukiwanie podobieństwa do idealnego rozwiązania i alternatywne opcje najbardziej wydajnego sprzętu górniczego ustalono na podstawie pomiarów odległości od rozwiązania idealnego przy zastosowaniu procedury rozmytej. Podejście takie jest wykorzystywane przy doborze optymalnych urządzeń do załadunku i transportu urobku w kopalni odkrywkowej Sungun w Iranie.