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1

Effect of an acetonized pyrolysis oil recycled from spent-car tires on coal flotation performance

Hasanizadeh Iman, Khoshdast Hamid, Rahmanian Ahmad, Asgari Kaveh, Hassanzadeh Ahmad

Physicochemical Problems of Mineral Processing

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2023

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Vol. 59, iss. 2

art. no. 163109

EN

In this paper, an extended Historical Data (HD) design was applied for evaluating the effect of an acetonized pyrolysis oil (PO) produced by pyrolysis of spent-car tires in coal. Experimental and statistical analyses were applied for examining the influence of some operating variables such as concentration of diesel oil (0, 10, and 20 L/t), pine oil (0.55, 0.1, and 1 L/t), and the pyrolysis oil (0, 10, and 20 L/t) as well as solid content of pulp (5, 10, and 15% (w/w)) on the yield and ash content of final concentrate. Fourier Transform Infrared Spectroscopy (FTIR) measurements showed that PO contained hydroxyl, aldehyde, aliphatic, and aromatic compounds. Based on the results of Analysis of Variance (ANOVA), the main effect of all variables, except concentration of pine oil, on the flotation responses were found significant. Batch flotation experimental results indicated that using pyrolysis oil resulted in a 2% increase in ash content and a 35% decrease of the yield, through a nonlinear trend. The curved behavior of flotation measures was due to the possible competitive adsorption between PO and diesel oil and nonselective interaction between pyrolysis oil and other reagents. The negative effect of PO on coal flotation efficiency was also ascribed to the interaction between hydrophilic groups in PO structure and the oxide nature of non-combustible materials of coal particles.

2

Study to Determine the Effect of Blade Distance and Chain Speed on the Productivity of Trench Excavators Using Taguchi Method

Giang Duong Truong

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no 4

139--149

EN

Chain trench excavators are widely used in the world for trenching in agriculture, laying underground cables, digging trenches. In this study, the research object is a small chain-type trench excavator. The purpose of the study is to evaluate and select the parameters of the chain loader to the machine productivity and evaluate the results of the experimental machine theory calculation. Experimental measurement parameters include machine speed when working, chain speed, blade distance adjustment on the chain. Research method is to conduct experiments using Taguchi method to design experiments and Minitab software to analyze data. Experimental results and numerical analysis determined that the optimal set of parameters was the distance of 2 cutting edges on the chain, the active sprocket rotation speed for the highest productivity. Compared with the results from the theory using the design, the deviation of the optimal parameters is less than 5%. Experimental process design and parameter influence analysis by Taguchi method, ANOVA analysis have identified reasonable parameters, highest productivity target.

3

Modeling and optimization of friction stir stitching of AISI 201 stainless steel via Box-Behnken design methodology

Ojo Olatunji Oladimeji, Obasha Isaac Ojo

Production Engineering Archives

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2022

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Vol. 28, Iss. 2

132--140

EN

The paper investigates the modelling and optimization of the notch-repaired/friction stir stitched AISI 201 stainless steel welds via the use of a non-consumable tool-based repair process. The repair process employs a sequential hopping-stitching approach. This approach involves the application of two intercepted and completely overlapped plunging actions of a probe-less titanium carbide tool to create an effective refilling and repair of the notched zone. Box-Behnken design (BBD) was employed for the experimental planning, modelling, and optimization of the notch-repair process. Tool rotational speed, penetration depth and dwell time of the tool were the studied process parameters while tensile strength was the response variable. A quadratic model was identified as the best model for the notch-repaired welds based on the combination of a low sequential P-value of 0.008216, a high lack of fit P-value of 0.931366, and a close to unity adjusted and predicted R-square values. The process parameter and their interaction effects on the tensile strength of the repaired notch were identified via the ANOVA analysis. Plunge depth (main effect) and interaction effect of tool rotational speed and dwell time had significant influences on the notch-repair process and the resultant tensile strength of the AISI 201 stainless steel. The visual representations of these effects were shown through the 2D elliptical contour and 3D response surface plots. The optimized process parameters were identified as 1215.9795 rpm, 0.40262212 mm, and 5.98706376 s while the resultant notch-repaired joint yielded a tensile strength of 886 MPa, which is close to the predicted value.

4

Optimisation of the Sublimation Textile Printing Process Using the Taguchi Method

Kumar Jeyaraman Anandha, Kumar M. Senthil

Fibres & Textiles in Eastern Europe

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2021

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Vol. 29, no. 1 (145)

75--79

EN

In this paper, printing parameters for the sublimation printing of polyester fabrics like the number of strokes, the sublimation paper weight in grams per square metre, the fusing temperature and time were optimised using the Tauguchi experimental design technique. In the evaluations the signal-to-noise ratio was used. Sixteen experiments were performed with respect to the L 16 Orthogonal array design for the Tauguchi approach. The results show a considerable improvement in the signal-to-noise ratio as compared to the initial conditions. Through this study, not only can optimum printing conditions for sublimation printed polyester fabr ics be obtained but also the significant factors that affect water vapour resistance.

PL

W pracy zoptymalizowano, przy użyciu eksperymentalnej techniki projektowania Tauguchi, parametry druku sublimacyjnego tkanin poliestrowych, takie jak: liczba pociągnięć, gramatura papieru sublimacyjnego w gramach na metr kwadratowy, temperatura i czas stapiania. W ocenach wykorzystano stosunek sygnału do szumu. Przeprowadzono 16 eksperymentów w odniesieniu do projektu macierzy ortogonalnej L 16 dla podejścia Tauguchi. Wyniki wskazały na znaczną poprawę stosunku sygnału do szumu w porównaniu z warunkami początkowymi. Dzięki zaprezentowanym badaniom można nie tylko uzyskać optymalne warunki drukowania na tkaninach poliestrowych drukowanych sublimacyjnie, ale także uwypuklić istotne czynniki wpływające na odporność na parę wodną.

5

Studies on separation of oil and peptides from saline wastewaters with the use of ceramic membranes

Ćwirko Konrad, Tomczak Elwira, Szaniawska Daniela

Proceedings of ECOpole

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2019

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Vol. 13, No. 1-2

9--16

EN

The work evaluates the effect of main process parameters, i.e. transmembrane pressure, TMP and cross-flow velocity, CFV on oil and protein rejection ri and permeate flux JVi using 22 experimental design. The ultrafiltration experiments were carried out using pilot installation with tubular ceramic 300 kDa membrane and model oil-in-water and BSA - water solutions. Ultrafiltration data obtained using experimental design technique was used to determine the regression coefficients of polynomial equations. These equations give information on non-conjugated as well as conjugated effects of two operating parameters on ultrafiltration process of model oil and BSA water solutions. Moreover, these equations helped to determine optimal conditions for ultrafiltration process from the point of view of membrane permeability and selectivity. Furthermore they can be useful while assessing the experimental conditions of ultrafiltration in real complex systems such as oily wastewaters produced by petroleum industry or marine transport and waste brines produced by fish industry.

PL

W pracy dokonano oceny wpływu parametrów procesowych, takich jak ciśnienie transmembranowe TMP oraz prędkość przepływu nadawy nad powierzchnią membrany CFV, na stopień odzysku oleju i białka ri oraz strumień permeatu Jvi z zastosowaniem planu czynnikowego dwupoziomowego. Doświadczenia prowadzono za pomocą pilotowej instalacji membranowej z ceramiczną membraną rurową o granicy rozdziału 300 kDa oraz modelowych roztworów oleju w wodzie oraz białka BSA w wodzie. Dane doświadczalne z przeprowadzonych procesów ultrafiltracji z zastosowaniem techniki planowanego eksperymentu zostały wykorzystane do określenia współczynników regresji równań wielomianowych. Równania te dostarczają informacji zarówno o niezwiązanym, jak i sprzężonym wpływie dwóch parametrów operacyjnych na proces ultrafiltracji modelowych roztworów wód zaolejonych oraz roztworów białka BSA w wodzie. Umożliwiają także określenie optymalnych warunków procesu ultrafiltracji z punktu widzenia przepuszczalności i selektywności membrany. Ponadto mogą być przydatne przy ocenie eksperymentalnych warunków tego procesu w układach rzeczywistych, takich jak ścieki zaolejone produkowane przez przemysł naftowy lub transport morski i solanki odpadowe produkowane przez przemysł rybny.

6

Coupled fuzzy logic and experimental design application for simulation of a coal classifier in an industrial environment

Khoshdast Hamid, Soflaeian Ali, Shojaei Vahideh

Physicochemical Problems of Mineral Processing

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2019

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Vol. 55, iss. 2

504--515

EN

Design of experiments (DOE) is an effective method providing useful information about the interaction of operating variables and the way the total system works by using statistical analyses. However, its industrial application is limited because it is almost difficult to maintain variables in DOE matrix at desired constant levels in industrial environment. Thus, this paper aims to present a new mixed modeling method which is a combination of fuzzy logic and design of experiments methods to overcome such practical limitations. The method first uses a fuzzy model which is trained by practical data gathered from industry to predict DOE response corresponding to each run in DOE matrix. Then, a statistical parametric model is constructed for the prediction of process response to any change of operating parameters under real industrial conditions. The proposed mixed method was successfully validated by using data obtained from a coal hydraulic classifier at Zarand Coal Washing Plant (Kerman, Iran). The method also seems to be a promising tool for modeling all devices and processes in real industrial environment and allows researchers to benefit from all the advantages of experimental design and fuzzy logic methods simultaneously.

7

Synthesis and characterization of binary and ternary nanocomposites based on TiO2, SiO2 and ZnO with PVA based template-free gel combustion method

Fakoori Elham, Karami Hassan, Nezhadali Azizollah

Materials Science Poland

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2019

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Vol. 37, No. 3

426--436

EN

Binary and ternary nanocomposites based on TiO2, SiO2 and ZnO were synthesized by PVA-based template-free gel combustion method. The morphology and the particles sizes of the synthesized samples depended on some parameters including the initial concentrations of metal salts and PVA amount in the sol, solvent composition and solution pH. Effects of these parameters were investigated and optimized by using the Taguchi method. In the experimental design, the Taguchi L25 array was used to investigate six factors at five levels. The samples were characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) specific surface areas, scanning electron microscopy (SEM). The obtained results showed that the present method can be used to synthesize TiO2/SiO2/ZnO ternary nanocomposite with an effective surface area of 0.3 m2 · g−1 and ZnO/TiO2, TiO2/SiO2, ZnO/SiO2 binary nanocomposites with an effective surface area of 234 m2 · g-1, 6 m2 · g-1 and 0.5 m2 · g-1, respectively. The ZnO/TiO2 nanocomposite which was synthesized under the following experimental conditions: 2.5 wt.% Zn salt, 2.5 wt.% Ti salt, 2.0 wt.% PVA, pH = 1 and ethanol:water ratio 30:70 was selected by the Taguchi method as an optimum sample with the smallest particles (average diameter = 50 nm).

8

Advanced Treatment of Pre-treated Commercial Laundry Wastewater by Adsorption Process: Experimental Design and Cost Evaluation

Veli Sevil, Arslan Ayla, Gülümser Çisil, Topkaya Eylem, Kurtkulak Hatice, Zeybek Şehriban, Dimoglo Anatoli, İşgören Melike

Journal of Ecological Engineering

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2019

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Vol. 20, nr 10

165--171

EN

In Turkey, the commercial laundry wastewater is usually discharged to the receiving water bodies and its reuse potential is ignored. This wastewater is grouped into the greywater due to their content of organic and inorganic pollutants. In recent years, the sequential processes have become more preferable in greywater treatment and reuse. In this study, a batch adsorption process was applied for further treatment of commercial laundry wastewater which is also pre-treated by means of the electrocoagulation process. In adsorption, two different composites of waste hazelnut shell derived activated carbons, which are supported with polyaniline (PAn/HS) and polypyrrole (PPy/HS), were used as adsorbents. The efficiency of the process was evaluated by means of an experimental design, and the response surface methodology was applied for this purpose. In the experiment with PAn/HS, the chemical oxygen demand (COD) 75% removal efficiency was accomplished with adsorbent dosage of 0.9 g, at pH 8, with 125 rpm mixing rate and for 77.5 min reaction time. For PPy/HS under the same experimental conditions, the COD removal efficiency was obtained as 20%. The utilization of waste hazelnut shell derived composites as adsorbents for commercial laundry wastewater treatment is a good alternative. The production costs of adsorbents were estimated as 0.70 USD/g and 3.21 USD/g for PAn/HS and PPy/HS, respectively. In terms of the production cost, the PAn/HS composite is approved more agreeable as adsorbents for commercial laundry wastewater treatment.

9

Statistical Analyses of Productivity Model Parameters for Process Improvement

Hussain Zahid

Advances in Science and Technology. Research Journal

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2019

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Vol. 13, no 2

157--167

EN

Productivity modeling and validation is the assessment of data to establish scientific indications that a process is stable. The aim of this paper is to present a novel approach using statistical analyses for process improvement. This study highlights the process behavior of three different lathe machines unit with the intention to replace one of them. The research methodology has illustrated by producing a steel rod of 3.175 millimeter diameter based on 180 samples collected from each machine. For statistical data value analysis, MS Excel 2016 and Minitab 18 were utilized. The results showed that lathe machine 1 and 2 had an equivalent inconsistency, but significantly different data spreads. Similarly, the throughput for machine 2 was higher with greater variability as compared to machine 1 while machine 3 encountered a low rate of throughput. On the basis of the fallouts of the analysis, the research team has officially suggested to substitute lathe machine 3.

10

Distributed scheduling of measurements in a sensor network for parameter estimation of spatio-temporal systems

Patan M., Kowalów D.

International Journal of Applied Mathematics and Computer Science

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2018

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Vol. 28, no. 1

39--54

EN

The main aim of the paper is to develop a distributed algorithm for optimal node activation in a sensor network whose measurements are used for parameter estimation of the underlying distributed parameter system. Given a fixed partition of the observation horizon into a finite number of consecutive intervals, the problem under consideration is to optimize the percentage of the total number of observations spent at given sensor nodes in such a way as to maximize the accuracy of system parameter estimates. To achieve this, the determinant of the Fisher information matrix related to the covariance matrix of the parameter estimates is used as the qualitative design criterion (the so-called D-optimality). The proposed approach converts the measurement scheduling problem to a convex optimization one, in which the sensor locations are given a priori and the aim is to determine the associated weights, which quantify the contributions of individual gaged sites to the total measurement plan. Then, adopting a pairwise communication scheme, a fully distributed procedure for calculating the percentage of observations spent at given sensor locations is developed, which is a major novelty here. Another significant contribution of this work consists in derivation of necessary and sufficient conditions for the optimality of solutions. As a result, a simple and effective computational scheme is obtained which can be implemented without resorting to sophisticated numerical software. The delineated approach is illustrated by simulation examples of a sensor network design for a two-dimensional convective diffusion process.

11

Dispersive liquid–liquid microextraction for the simultaneous determination of parent and nitrated polycyclic aromatic hydrocarbons in water samples

Borges B., Melo A., Ferreira I., Mansilha C.

Acta Chromatographica

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2018

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Vol. 30, no. 2

119--126

EN

A new method for simultaneous extraction and quantification of 6 nitrated polycyclic aromatic hydrocarbons (nitro-PAHs) and 16 parent polycyclic aromatic hydrocarbons (PAHs) in water matrices was optimized and validated. The extraction procedure was based on dispersive liquid-liquid microextraction technique, followed by gas chromatography-mass detection. The optimum conditions of extraction (volume of the extraction solvent, dispersive solvents and amount of salt) were selected using central composite design. The best results were found by using 200 μL of acetonitrile as dispersive solvent, 60 μL of chloroform as extraction solvent, and 10% (w/v) NaCl. Excellent linearity was observed in the range of 10–150 ng L−1 with correlation coefficients (r2) ranging between 0.9996 and 0.9999 for nitro-PAHs and in the range of 5–150 ng L−1 with r2 ranging from 0.9998 to 1.000 for PAHs. The limits of detection for the nitro-PAHs studied ranged from 0.82 to 3.37 ng L−1, whereas for PAHs ranged from 0.62 to 3.48 ng L−1. The intra- and inter-day precisions for nitro-PAHs were in the range of 0.45 to 19.54% and 0.43 to 19.62%, respectively, and for PAHs ranged between 0.45 to 17.42% and 0.38 to 18.97%, respectively. The proposed method was successfully applied in analyses of groundwater, sea, rain water and river water, being appropriate for routine analyses.

12

A study of the effect of operating parameters in column flotation using experimental design

Bedekovic G.

Physicochemical Problems of Mineral Processing

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2016

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Vol. 52, iss. 2

523--535

EN

The effect of air flow rate, pulp density and particle size was studied using central composite design for coal samples from the Lazy mine. Evaluation of column flotation tests was based on two dependant variables such as ash content and combustible matter recovery in the concentrate. The ash content in the concentrate was from 4.61 to 9.62% with the recovery of combustible matter from 17.43 to 81.98%. The ANOVA statistical analysis showed that the main effect of air flow rate has a significant impact on the combustible matter recovery and ash content in the concentrate. The main effect of pulp density on the combustible matter recovery is significant, whereas for the ash content it is not seen. There is a strong effect of the particle size on the ash content and combustible matter recovery in the concentrate. The interaction of the effect of the pulp density and particle size has a significant impact on the ash content in the concentrate.

13

Metodyka wyznaczenia korelacji wybranych wielkości eksploatacyjnych z parametrami złożowymi dla odwiertów udostepniających formacje łupkowe

Szott W., Miłek K.

Nafta-Gaz

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2016

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R. 72, nr 10

805--813

PL

W pracy przedstawiono metodykę wyznaczania korelacji wybranych wielkości eksploatacyjnych z parametrami złożowymi dla odwiertów udostępniających formacje łupkowe. Opiera się ona na statystycznej analizie dużego zbioru wariantów symulacyjnych, traktowanego jako schemat eksperymentów numerycznych, zgodnej z koncepcją tzw. experimental design. Uzyskane korelacje mogą być wykorzystane do znalezienia efektywnego rozwiązania problemu odwrotnego w procesie kalibracji złożowych modeli formacji łupkowych.

EN

The paper presents a method to determine effective correlations between production data and formation parameters of shale gas formations produced by horizontal, stimulated wells. The method is based upon the statistical analysis of a large collection of simulation models treated as a scheme of numerical experiments and using the so-called experimental design approach. The resultant correlations may be used to effectively solve the inverse problem of formation model calibration.

14

An analysis of factors influencing the determination of refractory materials’ compression strength

Gerle A., Czechowski J., Podwórny J., Dahlem E.

Materiały Ceramiczne

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2015

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T. 67, nr 3

324--332

EN

Cold crushing strength (CCS) testing is one of the basic tests conducted in order to characterize a refractory product. Compression strength is frequently a condition that must be fulfilled by a product to be technically accepted, and the result obtained in the test strongly depends on measuring conditions. For this reason, the applied measuring procedures must guarantee the repeatability and reproducibility of the obtained results. The standards in force specify CCS testing methods depending on the density of a product (dense and insulating products) and its form (shaped and unshaped products). These standards specify the requirements to be fulfilled by the dimensions of CCS test samples, their perpendicularity and parallelism, the requirements to be met by the machine used for CCS testing, the number of test samples as well as the sample loading rate during the test. However, not all standards sufficiently define all the requirements. Imprecise testing procedures and difficult to test inhomogeneous materials, such as refractories are, make it difficult to obtain repeatable and reproducible results and to compare them by different laboratories. The presented investigations are an initial part of international project ReStaR, aimed at specifying the factors which significantly influence among others the result of CCS testing. The investigations were based on experimental design methods and variance analysis, which allowed minimizing the number of experiments necessary to identify factors that have a considerable influence on CCS testing of refractory materials: dense shaped, insulating and unshaped products. It has been proved that the obtained result of CCS testing is significantly influenced by the quality of sample preparation and sample dimensions. In the case of insulating and unshaped products, an important factor turned out to be the rate of loading the sample during the test. In the case of all the types of materials subjected to testing, the use of a cardboard washer had a negative impact on the test result, reducing the value of strength and the repeatability of the obtained results.

PL

Badanie wytrzymałości na ściskanie w temperaturze otoczenia (CCS) jest jednym z podstawowych badań wykonywanych w celu scharakteryzowania wyrobu ogniotrwałego. Wytrzymałość na ściskanie jest często warunkiem odbioru technicznego wyrobu, a wynik uzyskany w trakcie badania silnie zależy od warunków pomiarowych. Sprawia to, że stosowane procedury pomiarowe muszą gwarantować powtarzalność i odtwarzalność uzyskiwanych wyników. Obowiązujące normy precyzują metody badania CCS w zależności od gęstości wyrobu (wyroby zwarte i izolacyjne) oraz od postaci wyrobu (wyroby formowane i nieformowane). Normy te określają wymagania dotyczące wymiarów próbek do badania CCS, ich prostopadłości i równoległości, wymagań, które musi spełniać maszyna stosowana do oznaczania CCS, ilości badanych prób oraz szybkości obciążania próbki w trakcie badania. Jednak nie wszystkie normy definiują wszystkie wymagania w wystarczającym stopniu. Nieprecyzyjne procedury badawcze w połączeniu z trudnym do badań, niejednorodnym materiałem, jakim jest materiał ogniotrwały, utrudnia otrzymywanie powtarzalnych i odtwarzalnych wyników oraz ich porównywanie między laboratoriami. Prezentowane badania stanowią początkową część międzynarodowego projektu ReStaR, mającą na celu wskazanie czynników istotnie wpływających między innymi na wynik badania CCS. W badaniach wykorzystano metody planowania eksperymentów i analizy wariancji, co pozwoliło na zminimalizowanie ilości eksperymentów niezbędnych do zidentyfikowania czynników istotnie wpływających na wynik badania CCS ogniotrwałych wyrobów zwartych formowanych, izolacyjnych i nieformowanych. Wykazano, że istotny wpływ na uzyskiwany wynik badania CCS ma jakość przygotowania próbki oraz jej wymiary. W przypadku wyrobów izolacyjnych i nieformowanych istotna okazała się szybkość obciążania próbki w trakcie badania. W przypadku wszystkich trzech badanych rodzajów materiałów stosowanie tekturowej podkładki negatywnie wpływało na wynik badania, obniżając wartość wytrzymałości i zmniejszając powtarzalność uzyskanych rezultatów.

15

Improvement of ductility for Twin Roll Cast and rolled AZ31 strips by use of Taguchi method

Ullmann M., Saleh H., Schmitdchen M., Kawalla R., Vogt H. P.

Archives of Civil and Mechanical Engineering

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2013

|

Vol. 13, no. 1

1--6

EN

Magnesium alloys have great potential in the area of lightweight production especially in the automotive industry due to their favorable combination of mechanical properties and low density. The effects of various rolling parameters on ductility were investigated using the Taguchi method. The optimum combination of process parameters has been found through analysis of main effects of ductility and signal-to-noise ratio, and the significant parameter were identified depending on analysis of variance. The results demonstrate that reduction is the most important factor for improving the ductility of the final strips, followed by rolling temperature and rolling speed. The optimal levels for the controllable factors were rolling temperature of 375 °C, rolling speed of 175 m/min and reduction of 70% for higher ductility.

16

Effect of laser cutting parameters on surface quality of low carbon steel (S235)

Zaied M, Bayraktar E., Katundi D., Boujelbene M., Miraoui I

Journal of Achievements in Materials and Manufacturing Engineering

|

2012

|

Vol. 54, nr 1

128--134

EN

Purpose: This work analysis surface roughness parameters as a function of Laser power and cutting speed. The surface roughness parameters are determined after statistical analysis (ANOVA) and propose a simple mathematical model. Design/methodology/approach: Machining were carried out by Laser cutting (CO2) of sheet metal (low carbon steel, S235) produces different surface quality. The statistical processing of the experimental results enabled development of a mathematical model to calculate the cut surface quality according to the cutting parameters used in the present work. Findings: The prediction of surface roughness values according to the mathematical model are very precisely analysis and determining of surface roughness values is a very practical tool by the experimental design method. It enables a high quality range in analysing experiments and achieving optimal exact values. A rather small experimental data are required to generate useful information and thus develop the predictive equations for surface roughness values as Ra, Rt and Rz. Depending on the surface roughness data provided by the experimental design, a first-order predicting equation has been developed in this paper. Practical implications: A simple and practical tool was proposed with the experimental design for predicting the surface roughness values as a function of variables of Laser power and cutting speed for a low carbon steel (S235). This type of analysis gives detailed information on the effect of Laser cutting parameters on the surface roughness. Originality/value: Experimental data was compared with modelling data to verify the adequacy of the model prediction. As shown in this work, the factor of cutting speed the most important influence on the surface roughness.

17

Regression Model for the Bagging Fatigue of Knitted Fabrics Produced from Viscose/Polyester Blended Rotor Yarns

Hasani H., Hassan Zadeh S.

Fibres & Textiles in Eastern Europe

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2012

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Vol. 20, no. 4 (93)

67--71

EN

The aim of this work was to predict the bagging fatigue percentage of knitted fabrics produced from viscose/polyester blended rotor yarns using blend ratios and structural cell stitch lengths as predictor variables. A simplex lattice design was used to determine the combinations of blend ratios of the fibre types. Knitted fabrics with three different structures were produced from viscose/polyester blended rotor yarns. Mixture-process crossed regression models with two mixture components and one process variable (structural cell stitch lengths, blend ratio) were built to predict the bagging fatigue percentage. All statistical analysis steps were implemented using Design-Expert statistical software. The correlation coefficient between the bagging fatigue percentage predicted and the bagging fatigue percentage observed was 0.983, indicating the strong predictive capability of the regression model built.

PL

Badano wypychanie dzianin wykonanych z wiskozowo-poliestrowych mieszankowych przędz rotorowych. Jako wielkości wejściowe przyjęto procentowy udział włókien w mieszankach splotu. Zastosowano konstrukcję sympleksu dla określenia kombinacji stosunku składników przędzy mieszankowej. Wyprodukowano trzy rodzaje dzianin przy użyciu rożnych mieszanek przędz, utworzono model regresji zawierający dwa składniki mieszanki i jedną zmienną procesu - długość splotu dziewiarskiego. Przeprowadzono analizę statystyczną przy wykorzystaniu programu Design-Expert. Uzyskano bardzo dobrą zgodność pomiędzy wartościami przewidywanymi i pomierzonymi, współczynnik korelacji wynosił 0.983.

18

Technical assistance to the decision for the choice of a physical configuration

Benmoussa R.

Polish Journal of Management Studies

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2011

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Vol. 3

44-60

EN

In this paper a technique for decision support for selecting a physical configuration are presented. This technique is useful during the redesign of a proposed restructuring of production processes resulted in a BPR approach. Based on the use of simulation and from the traditional experimental designs. It involves assessing the ability of the said configuration to cope with external and internal changes it faced. Our evaluation process is essentially based on the criterion of flexibility, this perverse concept and the ability of the configuration to accommodate the possible future directions for the installation of one or more measures of progress. Our work is illustrated by a case study.

PL

W artykule przedstawiono techniki wspomagania decyzji wyboru fizycznej konfiguracji. Przedstawiona technika jest przydatna w trakcie przebudowy planowanej restrukturyzacji procesów produkcyjnych co odzwierciedla podejście BPR, opierające się na korzystaniu z symulacji i tradycyjnych wzorów doświadczalnych. Technika polega ona ocenie zdolności tej konfiguracji do radzenia sobie z wewnętrznymi i zewnętrznymi zmianami. Proces oceny opiera się głównie na kryterium elastyczności, koncepcja ta jest przewrotna i daje możliwości konfiguracji w celu uwzględnienia możliwych przyszłych kierunków w zakresie instalacji jednego lub więcej środków postępu. Praca ilustruje studium przypadku.

19

Prediction of surface roughness by experimental design methodology in Electrical Discharge Machining (EDM)

Ben Salem S., Tebni W., Bayraktar E.

Journal of Achievements in Materials and Manufacturing Engineering

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2011

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Vol. 49, nr 2

150--157

EN

Purpose: This work models the Ra parameter as a function of current intensity (I), the electrode material and the work material. The surface is directly related to the average intensity (I) during machining. If the intensity is increased to 25 A, the roughness of the room rises dramatically to 15 microns. Design/methodology/approach: Machining with a copper tool produces a better surface than can be achieved by a graphite tool. Copper tool machining has been performed in an efficient way, eliminating the necessity of a large number of experiments. The statistical processing of the results enabled development of a mathematical model to calculate the machined surface quality according to the parameters of the cut used. Findings: The mathematical model, which precisely determines surface roughness, is a tool for cutting parameters and has been obtained by the experimental design method. It enables a high quality range in analysing experiments and achieving optimal exact values. A relatively small number of designed experiments are required to generate useful information and thus develop the predictive equations for surface roughness. Depending on the surface roughness data provided by the experimental design, a first-order predicting equation has been developed. Practical implications: The experimental design was proposed for predicting the relative importance of various factors (composition of the steels and electrical discharge machining (EDM) processing conditions) to obtain efficient pieces. This model gives detailed information on the effect of parameters of cut on the surface roughness. Originality/value: Experimental data was compared with modelling data to verify the adequacy of the model prediction. As shown in this work, the factor of intensity has the most important influence on the surface roughness.

20

Enantioselective separation and determination of citalopram enantiomers in pharmaceutical dosage form and bulk drug using experimental design approach on Chiralcel® OC as a chiral stationary phase

Semreen M. H, Aboul-Enein H. Y.

Acta Chromatographica

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2011

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Vol. 23, no. 3

389--401

EN

An enantioselective HPLC method was developed and validated for the separation and the estimation of citalopram (CIT) enantiomers in bulk drug and pharmaceutical preparations. The method was validated for its linearity (correlation coefficient = 0.9994 and 0.996 for S-(+)-enantiomer and R-(−)-enantiomer, respectively), accuracy, robustness, and intermediate precision. Experimental design was applied during intermediate precision (full factorial 2 3 design) and robustness testing (Box Benken as a factorial design), for robustness test three factors were considered: percentage of organic modifier, flow rate, and temperature. The separation was achieved on cellulose tris(phenylcarbamate) known as Chiralcel® OC (25 cm, 4.6 mm i.d.) derivatized cellulose (phenyl carbamate), with UV detection at 245 nm using n-hexane-isopropanoldiethylamine (85:15:0.2, υ/υ/υ) as mobile phase at flow rate 0.7 mL min−1. A decrease in the flow rate results in decreasing the selectivity factor (α), while varying the percentage of n-hexane and the temperature have no effect on selectivity factor (α). For intermediate precision, the variables considered were analyst, equipment, and day. The RSD% value (0.73%, n = 24) indicates a good precision for the analytical procedure. The method was found to be suitable for determination of enantiomeric purity of CIT in bulk drugs and pharmaceutical formulations.