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1

Improving grinding ball lifespan and efficiency through hardenability modelling and optimization

Aissat Sahraoui, Safa Ali

Advances in Materials Science

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2023

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Vol. 23, nr 3(77)

5--20

EN

Grinding balls are spherical or cylindrical components used in grinding and milling operations to reduce the size of particles and achieve a finer product. They are made of high chromium white cast iron (HCWCI) and used in a variety of industrial processes. The efficiency of the grinding process is heavily influenced by the properties of the grinding balls, including their composition, size, and hardness. As such, there is ongoing research and development to improve the performance and durability of grinding balls, with the aim of countering the extreme conditions of wear and impact that cause a reduction in their lifespan. This study involved austenitizing balls with diameters of 50 mm and 70 mm at temperatures of 950°C and 1050°C, followed by quenching using both oil and compressed air. By exploiting the experimental HRC hardness results obtained in this work, the study aims to find a mathematical model relating the response (hardenability) to the main effects (austenitization temperature, quenching medium, and diameter balls) and their interactions. Analysis of variance (ANOVA) was used to establish the statistical significance parameters and an optimization of response by the best sub-models method and by the desirability function is realized in the second part of this work. It seems that the austenitization temperature and the size of the balls have a stronger impact on the hardenability of the balls than the cooling rate (quenching medium) by reducing the hardness difference between the surface and the medium of the ball to minimal values.

2

Modeling and parametric optimization of friction stir welding of aluminium alloy AA7068-T6 using response surface methodology and desirability function analysis

Bindu M. D., Tide P. S., Bhasi A. B., Ramachandran K. K.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2021

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Vol. 69, nr 4

art. no. e137936

EN

In this investigation, high specific strength precipitation hardenable alloy AA7068-T6 was joined using friction stir welding. Experiments were carried out using the three factor-three level central composite face-centered design of response surface methodology. Regression models were developed to assess the influence of tool rotational speed, welding speed, and axial force on ultimate tensile strength and elongation of the fabricated joints. The validity of the developed models was tested using the analysis of variance (ANOVA), actual and adjusted values of the regression coefficients, and experimental trials. The analysis of the developed models together with microstructural studies of typical cases showed that the tool rotational speed and welding speed have a significant interaction effect on the tensile strength and elongation of the joints. However, the axial force has a relatively low interaction effect with tool rotational speed and welding speed on the strength and elongation of the joints. The process variables were optimized using the desirability function analysis. The optimized values of joint tensile strength and elongation – 516 MPa and 21.57%, respectively were obtained at a tool rotational speed of 1218 rpm, welding speed of 47 mm/ min, and an axial force of 5.3 kN.

3

Analytical quality by design approach for the control of potentially counterfeit chloroquine with some NSAIDS using HPLC with fluorescence detection in pharmaceutical preparation and breast milk

Hassan Said A., Ibrahim Noha, Elzanfaly Eman S., El Gendy Ahmed E.

Acta Chromatographica

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2021

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Vol. 33, no. 3

234--244

EN

Chloroquine phosphate (CQ) the antimalarial drug and suggested to treat the pandemic disease coronavirus (COVID-19) is often adulterated with some of the non-steroidal anti-inflammatory drugs (NSAIDs) such as paracetamol, aspirin (ASP), or both. The purpose of this study is to detect such counterfeited drugs, using a reversed phase high pressure liquid chromatography (RP-HPLC) method with fluorescence detection. Analysis was divided into three phases. In the first phase, a Plackett-Burman design (PBD) was used to screen five independent factors, namely, buffer pH, buffer concentration (mM), acetonitrile content (%), flow rate (mL/min) and triethylamine (TEA) content in the buffer preparation (%). The selected dependent variables were (resolution, symmetry of peaks and run time). The objective of the second phase was to optimize the method performance using Box-Behnken design (BBD) and desirability function for multiple response optimization to obtain the best chromatographic performance with the shortest run time. Optimal chromatographic separation was achieved on a YMC-pack pro C18 ODS-A column (15 cm × 4.6 mm, 5 µm) at room temperature The optimum mobile phase consisted of acetonitrile and 5 mM sodium dihydrogen phosphate buffer containing 0.5% triethyamine (30:70, v/v) with the pH adjusted to 3.5 using an orthophosphoric acid solution. The flow rate was maintained at 1 mL/min, and the detection was performed with a fluorescence detector fixed at 380 nm(λemission) after excitation at 335 nm(λexcitation). The third phase was method validation according to ICH guidelines, providing to be specific, precise, accurate, and robust. The method is linear over a range of 0.4–8 µg/mL for chloroquine and ASP, while for paracetamol it is linear over 16–48 µg/mL. The developed RP-HPLC method was used for quantitation of the three drugs in chloroquine dosage form samples. The method shows a great tendency in the classification between the genuine chloroquine and the adulterated ones in pharmaceutical preparations and breast milk.

4

A new direction in design and manufacture of co-sensitized dye solar cells : toward concurrent optimization of power conversion efficiency and durability

Hosseinnezhad M., Shadman A., Saeb M. R., Mohammadi Y.

Opto-Electronics Review

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2017

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Vol. 25, No. 3

229--237

EN

A novel methodology was implemented in the present study to concurrently control power conversion efficiency (η) and durability (D) of co-sensitized dye solar cells. Applying response surface methodology (RSM) and Desirability Function (DF), the main influential assembling (dye volume ratio and anti-aggregation agent concentration) and operational (performance temperature) parameters were systematically changed to probe their main and interactive effects on the η and D responses. Individual optimization based on RSM elucidated that D can be solely controlled by changing the ratio of vat-based organic photosensitizers, whereas η takes both effects of dye volume ratio and anti-aggregation concentration into account. Among the studied factors, the performance temperature played the most vital role in η and D regulation. In particular, however, multi-objective optimization by DF explored the degree to which one should be careful about manipulation of assembling and operational parameters in the way maximization of performance of a co-sensitized dye solar cell.

5

An improvement of the ant algorithm for the maximum clique problem

Schiff K.

Czasopismo Techniczne. Elektrotechnika

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2015

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Y. 112, iss. 2-E

225--233

EN

The maximum clique problem is a very well-known NP-complete problem and for such a problem, meta-heuristic algorithms have been developed which ant algorithms belongs to. There are many algorithms including ant algorithms that have been elaborated for this problem. In this paper, a new dynamic function of selecting with a new improvement procedure in order to get a larger size of clique for the ant algorithm is presented and this search for the maximum clique in graph is compared to the best ant algorithms that are already known.

PL

Problem kliki maksymalnej przynależy do klasy problemów NP-zupełnych i dla takich problemów opracowuje się obecnie algorytmy metaheurystyczne, do których zaliczają się algorytmy mrówkowe. W niniejszym artykule prezentowany jest algorytm mrówkowy z dynamiczną funkcją wyboru wierzchołków włączanych do tworzonej kliki przez każdą mrówkę wraz z procedurą poprawy wymiaru otrzymanej kliki poprzez wymianę wierzchołków, a otrzymany algorytm został porównany z innymi już dotychczas opublikowanymi.

6

Simulation and optimization of heavy-duty semitrailer dynamic model

Korta J., Martowicz A., Gallina A., Uhl T.

Journal of KONBiN

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2011

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No. 4 (20)

85--106

EN

This paper presents an optimization of a multibody truck semitrailer model; its purpose was to find the best values of suspension parameters in order to minimize the disadvantageous influence of force distribution in the high risk areas. A number of simulations with different parameters and under different load cases have been carried out, combined with a parametric and structural sensitivity analysis, and in this way individual factors influencing particular forces have been estimated. The stiffness and damping coefficients of the construction suspension system have been adjusted by applying metamodeling techniques, using two different approaches: Kriging and polynomial regression. Finally, using a desirability function, the most optimal solution has been found.

PL

Artykuł przedstawia proces optymalizacji systemu zawieszenia wirtualnego modelu dynamicznego naczepy samochodowej, przeznaczonej dla pojazdów transportu ciężkiego. Celem podjętych prób było znalezienie wartości charakteryzujących odpowiedź układu na wymuszenia dynamiczne, minimalizujących ich niekorzystny wpływ na punkty konstrukcyjne, będące narażone na nadmierne obciążenia. Przeprowadzono szereg symulacji numerycznych, w oparciu o wyniki których określono wrażliwość systemu na zmieniające się parametry konstrukcyjne oraz użytkowe. Optymalne wartości współczynników tłumienia oraz sztywności badanego systemu obliczono z wykorzystaniem konwersji zagadnienia na monokryterialny problem decyzyjny, w oparciu o skonstruowane dwiema metodami (tj. Kriging i regresją wielomianową) powierzchnie odpowiedzi.

7

A comparative quality optimisation between ring spun and slub yarns by using desirability function

Souid H., Babay A., Sahnoun M., Cheikrouhou M.

Autex Research Journal

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2008

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Vol. 8, no. 3

72--76

EN

The present study was conducted to develop a credible approach to determine the quality of ring spun and slub yarns by virtue of criteria incorporating combinations of the fundamental fiber characteristics. Critical yarn parameters are to be investigated. The values of these tested properties were introduced into a database that ranked the quality of the yarn against industry standards. The paper investigates the possibilities of using the global optimization superimposed diagram response surface methodology in order to identify the spinner feasibility conditions across the customer yarn quality requirements. The spinner approach consists of optimizing the yarn count and twist. We have also studied the customer approach to optimize the yarn responses simultaneously by the use of the desirability functions. The response optimizer searches for a combination of input variables that jointly optimize the set of the responses by satisfying the customer requirements for each response in the set.