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Shale gas has a permeability of <0.1 mD and a porosity of around 2% - 8% to produce gas that rises to the surface through hydraulic fracturing and horizontal drilling. Geomechanics is one of the important factors that influence the success of a hydraulic fracturing job. Technology in fractures makes geomechanics a clear factor in predicting the success or failure of rocks in deformation and knowing the properties that will be faced by fracture fluids which will later be used to see the effectiveness of fracture fluids in resisting fractures. High operational costs need to be studied further to determine the parameters that affect hydraulic fracturing work, especially from the geomechanical aspect to minimize production failures and work safety. The research conducted this time focuses on the sensitivity of geomechanical parameters by using CMG (GEM) reservoir simulations for reservoir models and conducting Response Surface Methodology (RSM) in selection and ease when applied in the field prior to the hydraulic fracturing process. In this sensitivity study carried out on 5 parameters namely stress, Poisson's ratio, Young's modulus, biot coefficient, and pore pressure. The geomechanical parameter that has the most influence on hydraulic fracturing work based on the sensitivity results carried out through 500 data sets using the Analysis of Variance obtained R2 = 0.99 with the results based on the importance value of the pore pressure variable of 3.8. Then Young's modulus is 0.28, stress is 0.12, Poisson's ratio is 0.08, and biot coefficient is 0.04.

Shale gas has a permeability of <0.1 mD and a porosity of around 2% - 8% to produce gas that rises to the surface through hydraulic fracturing and horizontal drilling. Geomechanics is one of the important factors that influence the success of a hydraulic fracturing job. Technology in fractures makes geomechanics a clear factor in predicting the success or failure of rocks in deformation and knowing the properties that will be faced by fracture fluids which will later be used to see the effectiveness of fracture fluids in resisting fractures. High operational costs need to be studied further to determine the parameters that affect hydraulic fracturing work, especially from the geomechanical aspect to minimize production failures and work safety. The research conducted this time focuses on the sensitivity of geomechanical parameters by using CMG (GEM) reservoir simulations for reservoir models and conducting Response Surface Methodology (RSM) in selection and ease when applied in the field prior to the hydraulic fracturing process. In this sensitivity study carried out on 5 parameters namely stress, Poisson's ratio, Young's modulus, biot coefficient, and pore pressure. The geomechanical parameter that has the most influence on hydraulic fracturing work based on the sensitivity results carried out through 500 data sets using the Analysis of Variance obtained R2 = 0.99 with the results based on the importance value of the pore pressure variable of 3.8. Then Young's modulus is 0.28, stress is 0.12, Poisson's ratio is 0.08, and biot coefficient is 0.04.

This project aims to investigate and develop a methodology for encapsulating olive oil spheres using an alginate-based hydrogel, without altering the main physico-chemical and organoleptic properties of the oil. The rapid advancements in high-end culinary techniques claim to provide innovative ways of presenting olive oil while preserving traditions and cultural values. To achieve this objective, an extensive research effort has been dedicated to the field of olive oil and encapsulation. Existing literature confirms that current processes for oil encapsulation of- ten compromise the integrity of the encapsulated oil due to the use of high temperatures and/or emulsification. In this project, a series of tests were conducted to explore feasible methods of encapsulating oil without harming its properties. The designed methodology involves freezing olive oil within a calcium lactate solution and subsequently immersing it in a low-temperature alginate bath. To gain a deeper understanding of the encapsulation process and identify areas for improve- ment, a statistical study utilizing Response Surface Methodology (RSM) was performed. The study involved varying the concentrations of calcium lactate and alginate, the main factors in- fluencing the process. Multiple responses, including the percentage of formation, sphericity index, and rupture strength of the spheres, were evaluated to determine the optimal conditions for encapsulation. The second phase of the project focused on verifying that the encapsulation methodology had no adverse impact on the quality of the olive oil. This verification was accomplished through two means: chemical analysis and organoleptic analysis. The chemical analysis involved as- sessing the oxidative state of the olive oil before and after encapsulation by measuring pa- rameters such as the peroxide value, K232, K270, and ∆K values. The organoleptic analysis was carried out by a group of expert tasters, the "Panell de Tast Oficial d’olis Verges, Aquest projecte té com a objectiu investigar i desenvolupar una metodologia per encapsular esferes d’oli d’oliva d’alginat, sense alterar les propietats fisicoquímiques i organolèptiques de l’oli. Els ràpids avenços en les tècniques culinàries d’alta gamma pretenen oferir formes innovadores de presentar l’oli d’oliva preservant les tradicions i els valors culturals. Per això, s’ha realitzat una extensa recerca bibliogràfica amb l’oli d’oliva i l’encapsulació com a paraules clau. La bibliografia existent confirma que els processos actuals d’encapsulació de l’oli sovint afecten les propietats les seves propietats a causa de l’ús d’altes temperatures i/o de l’emulsionament. En aquest projecte, s’han realitzat una sèrie de proves per explorar mètodes viables per encapsular l’oli sense danyar-lo. La metodologia dissenyada consisteix a congelar l’oli d’oliva envoltat d’una solució de lactat de calci i la seva posterior immersió en un bany d’alginat a baixa temperatura. Per aprofundir en el coneixement del procés d’encapsulació i identificar àrees de millora, s’ha realitzat un estudi estadístic utilitzant la Metodologia de Superfície de Resposta (RSM). L’estudi ha consistit a variar les concentracions de lactat de calci i alginat, els principals factors que in- flueixen en el procés. S’han obtingut múltiples respostes, com ara el percentatge de formació, l’índex d’esfericitat i la resistència a la ruptura de la massa, per determinar les condicions òptimes d’encapsulació. La segona fase del projecte s’ha centrat a verificar que la metodologia d’encapsulació no tenia influència en la qualitat de l’oli d’oliva. Aquesta comprovació s’ha dut a terme per dos mitjans: l’anàlisi químic i l’anàlisi organolèptic. L’anàlisi químic ha consistit a avaluar l’estat oxidatiu de l’oli d’oliva abans i després de l’encapsulació mitjançant la mesura de paràmetres com ara l’índex de peròxid, els valors K232, K270 i ∆K. L’anàlisi organolèptic ha estat realitzat per un panel de tast, el "Panell, Este proyecto tiene como objetivo investigar y desarrollar una metodología para encapsular es- feras de aceite de oliva de alginato, sin alterar las propiedades fisicoquímicas y organolépticas del aceite. Los rápidos avances en las técnicas culinarias de alta gama pretenden ofrecer formas innovadoras de presentar el aceite de oliva preservando las tradiciones y los valores culturales. Para ello, se ha realizado una extensa búsqueda bibliográfica con el aceite de oliva y la encap- sulación como palabras clave. La bibliografía existente confirma que los procesos actuales de encapsulación del aceite a menudo afectan a las propiedades del aceite encapsulado debido al uso de altas temperaturas y/o a la emulsificación. En este proyecto, se han realizado una serie de pruebas para explorar métodos viables de encapsular aceite sin dañarlo. La metodología diseñada consiste en congelar aceite de oliva rodeado de una solución de lactato de calcio y su posterior inmersión en un baño de alginato a baja temperatura. Para profundizar en el conocimiento del proceso de encapsulación e identificar áreas de mejora, se ha realizado un estudio estadístico utilizando la Metodología de Superficie de Respuesta (RSM). El estudio ha consistido en variar las concentraciones de lactato de calcio y alginato, los principales factores que influyen en el proceso. Se han obtenido múltiples respuestas, como el porcentaje de formación, el índice de esfericidad y la resistencia a la rotura de la masa para determinar las condiciones óptimas de encapsulación. La segunda fase del proyecto se ha centrado en verificar que la metodología de encapsulación no tenía influencia en la calidad del aceite de oliva. Esta comprobación se ha llevado a cabo por dos medios: el análisis químico y el análisis organoléptico. El análisis químico ha con- sistido en evaluar el estado oxidativo del aceite de oliva antes y después de la encapsulación midiendo parámetros como el índice de peróxido, los valores K232, K270 y ∆K. E

Purpose This study aims to present a novel methodology for the evaluation of tribological properties of new nanocomposites with the A356 alloy matrix reinforced with aluminium oxide (Al2O3) nanoparticles. Design/methodology/approach Metal matrix nanocomposites (MMnCs) with varying amounts and sizes of Al2O3 particles were produced using a compocasting process. The influence of four factors, with different levels, on the wear rate, was analysed with the help of the design of experiments (DoE). A regression model was developed by using the response surface methodology (RSM) to establish a relationship between the observed factors and the wear rate. An artificial neural network was also applied to predict the value of wear rate. Adequacy of models was compared with experimental values. The extreme values of wear rate were determined with a genetic algorithm and particle swarm optimization using the RSM model. Findings The combination of optimization methods determined the values of the factors which provide the highest wear resistance, namely, reinforcement content of 0.44 wt.% Al2O3, sliding speed of 1 m/s, normal load of 100 N and particle size of 100 nm. Used methods proved as effective tools for modelling and predicting of the behaviour of aluminium matrix nanocomposites. Originality/value The specific combinations of the optimization methods has not been applied up to now in the investigation of MMnCs. In addition, using of small content of ceramic nanoparticles as reinforcement has been poorly investigated. It can be stated that the presented approach for testing and prediction of the wear rate of nanocomposites is a very good base for their future research.

Abrasive water jet machining (AWJM) of aircraft material is a difficult process using conventional machines. Machined parts of Inconel 718, a nickel-based alloy (aircraft material) are widely used in the aerospace industries. However, these alloys are expensive and difficult to machine. The objective of this article is to optimize AWJM process parameters. Response Surface Methodology (RSM) is planned with travel speed, abrasive flow rate, and stand-off distance as inputs. The response models of surface finish and cone angle show the correlation coefficient `R2` of 96.94% and 96.67%, respectively. 3D surface plot with analysis of variance (ANOVA) is presented to distinguish significant AWJM parameters. The work revealed that travel speed is a significant factor for surface finish and cone angle. Multi-response optimization results in the best optimal values of traverse speed; abrasive flow rate and standoff distance are 200 mm/min, 460 g/min, and 4 mm respectively. This research outcome showed more than 90 % of accuracy for both the responses. This article is helpful to the AWJM centers to select optimal machining parameters for achieving the desirability in the machining of Inconel 718. The obtained novel results confirmed that such a technique can be implemented to identify optimal parameters in the machining of different materials.

Abrasive water jet machining (AWJM) of aircraft material is a difficult process using conventional machines. Machined parts of Inconel 718, a nickel-based alloy (aircraft material) are widely used in the aerospace industries. However, these alloys are expensive and difficult to machine. The objective of this article is to optimize AWJM process parameters. Response Surface Methodology (RSM) is planned with travel speed, abrasive flow rate, and stand-off distance as inputs. The response models of surface finish and cone angle show the correlation coefficient `R2` of 96.94% and 96.67%, respectively. 3D surface plot with analysis of variance (ANOVA) is presented to distinguish significant AWJM parameters. The work revealed that travel speed is a significant factor for surface finish and cone angle. Multi-response optimization results in the best optimal values of traverse speed; abrasive flow rate and standoff distance are 200 mm/min, 460 g/min, and 4 mm respectively. This research outcome showed more than 90 % of accuracy for both the responses. This article is helpful to the AWJM centers to select optimal machining parameters for achieving the desirability in the machining of Inconel 718. The obtained novel results confirmed that such a technique can be implemented to identify optimal parameters in the machining of different materials.

This study has developed an improved and fast microwave-assisted procedure for extraction of high yields of natural antioxidants from artichoke leaves dust. The material is derived as an abundant residue remained after processing for the industrial tea blends preparation, having no commercial value. A key factors for optimization of the total polyphenolic (TPC) and flavonoid content (TFC) and antioxidant activities have been determined by using single factor experiments along with a response surface methodology. The optimal conditions for maximizing the combination of TPC/TFC and antioxidant activity were obtained as follows: ethanol concentration 67.81%, extraction time 50 s, liquid/solid ratio 41.78 mL/g, microwave power 180 W, whereas the corresponding responses resulted in: TPC - 205.59 +/- 7.30 mg GAE/g dw, TFC - 79.75 +/- 1.12 mg QE/g dw, and FRAP -1008.14 +/- 37.15 mmolFe2+/g dw. Only 14.7 mu g/mL of the extract concentration is required to inhibit 50% of DPPH free radicals. A comparative study confirmed that the proposed procedure yielded higher TPC, TFC and antioxidant activities than available extraction methods. It highlights a several fold reduced extraction time, caring an ecofriendly principle for obtaining of antioxidants from industrial, medicinal crop residues, which would be further easily valorized in food and pharmaceutical industry.

This study has developed an improved and fast microwave-assisted procedure for extraction of high yields of natural antioxidants from artichoke leaves dust. The material is derived as an abundant residue remained after processing for the industrial tea blends preparation, having no commercial value. A key factors for optimization of the total polyphenolic (TPC) and flavonoid content (TFC) and antioxidant activities have been determined by using single factor experiments along with a response surface methodology. The optimal conditions for maximizing the combination of TPC/TFC and antioxidant activity were obtained as follows: ethanol concentration 67.81%, extraction time 50 s, liquid/solid ratio 41.78 mL/g, microwave power 180 W, whereas the corresponding responses resulted in: TPC − 205.59 ± 7.30 mg GAE/g dw, TFC − 79.75 ± 1.12 mg QE/g dw, and FRAP −1008.14 ± 37.15 mmolFe2+/g dw. Only 14.7 µg/mL of the extract concentration is required to inhibit 50% of DPPH free radicals. A comparative study confirmed that the proposed procedure yielded higher TPC, TFC and antioxidant activities than available extraction methods. It highlights a several fold reduced extraction time, caring an eco-friendly principle for obtaining of antioxidants from industrial, medicinal crop residues, which would be further easily valorized in food and pharmaceutical industry.

This study has developed an improved and fast microwave-assisted procedure for extraction of high yields of natural antioxidants from artichoke leaves dust. The material is derived as an abundant residue remained after processing for the industrial tea blends preparation, having no commercial value. A key factors for optimization of the total polyphenolic (TPC) and flavonoid content (TFC) and antioxidant activities have been determined by using single factor experiments along with a response surface methodology. The optimal conditions for maximizing the combination of TPC/TFC and antioxidant activity were obtained as follows: ethanol concentration 67.81%, extraction time 50 s, liquid/solid ratio 41.78 mL/g, microwave power 180 W, whereas the corresponding responses resulted in: TPC - 205.59 +/- 7.30 mg GAE/g dw, TFC - 79.75 +/- 1.12 mg QE/g dw, and FRAP -1008.14 +/- 37.15 mmolFe2+/g dw. Only 14.7 mu g/mL of the extract concentration is required to inhibit 50% of DPPH free radicals. A comparative study confirmed that the proposed procedure yielded higher TPC, TFC and antioxidant activities than available extraction methods. It highlights a several fold reduced extraction time, caring an ecofriendly principle for obtaining of antioxidants from industrial, medicinal crop residues, which would be further easily valorized in food and pharmaceutical industry.

Developing more energy-efficient and environmentally friendly transportation technologies, that can enable to use significantly less petroleum and to reduce regulated emissions while meeting or exceeding drivers’ performance expectations, has always been one of the main challenges in automotive technology. Therefore, based on an experimental dataset, metamodels were generated using design of computer experiments and central composite design technique in order to accurately predict carbon monoxide (CO), oxides of nitrogen (NO x), hydrocarbon (HC) and carbon dioxide (CO 2) emissions, mean effective pressure and exergy destruction due to heat transfer and combustion process. Combustion metamodels was evaluated varying air–fuel ratio, ignition timing [(°CAD) Crank Angle Degrees], compression ratio, and combustion duration (°) on the performance of a Spark Ignition (SI) engine at constant speed of 750 rpm. Because SI gasoline engines always encounter the decreased thermal efficiency and increased toxic emissions at idle (Jurgen in Automotive electronics handbook, McGraw-Hill, New York, 1995). The Akaike information criterion was applied to automatically select the best metamodel for each case. © 2019, Springer-Verlag France SAS, part of Springer Nature.

Developing more energy-efficient and environmentally friendly transportation technologies, that can enable to use significantly less petroleum and to reduce regulated emissions while meeting or exceeding drivers’ performance expectations, has always been one of the main challenges in automotive technology. Therefore, based on an experimental dataset, metamodels were generated using design of computer experiments and central composite design technique in order to accurately predict carbon monoxide (CO), oxides of nitrogen (NO x), hydrocarbon (HC) and carbon dioxide (CO 2) emissions, mean effective pressure and exergy destruction due to heat transfer and combustion process. Combustion metamodels was evaluated varying air–fuel ratio, ignition timing [(°CAD) Crank Angle Degrees], compression ratio, and combustion duration (°) on the performance of a Spark Ignition (SI) engine at constant speed of 750 rpm. Because SI gasoline engines always encounter the decreased thermal efficiency and increased toxic emissions at idle (Jurgen in Automotive electronics handbook, McGraw-Hill, New York, 1995). The Akaike information criterion was applied to automatically select the best metamodel for each case. © 2019, Springer-Verlag France SAS, part of Springer Nature.

The feasibility of using intermittent cycle extended aeration system (ICEAS) sludge as a lipid feedstock for biodiesel production was investigated. The main effects of in situ transesterification parameters, reaction temperature (30–70 °C), reaction time (4–24 h), catalyst concentration (1–5% v/v), and proportion of methanol to dry sludge (5–25 ml/g) at five-levels as well as their simultaneous interactions were evaluated to develop an empirical model. Optimized conditions were obtained at 60 °C, 4.65% (v/v) H2SO4, 17.84 h reaction time, and 5:1 methanol to dry sludge proportion (ml/g), leading to a maximum of 18.58% (w/w) biodiesel yield with 94.23% fatty acid methyl ester content. This result was higher in comparison with yields derived from conventional activated sludge, membrane bioreactor and anaerobic-anoxic-oxic processes. The ICEAS technology advantages are owned to its different configurations leading to production of one blended sludge, shorter hydraulic retention time and higher chemical oxygen demand to nitrogen ratios. The predominance of fatty acid methyl esters such as palmitic, oleic, palmitoleic, stearic, linoleic and myristic acid methyl ester, in the obtained biodiesel, indicated suitability of ICEAS sludge as feedstock for biodiesel production.

This work demonstrates the usefulness of SilA laccase from Streptomyces ipomoeae to functionalize Kraft lignin to be used as a thickener in the preparation of biodegradable oleogels for lubricating purposes. First, conditions for the enzymatic reaction were optimized by determining the polymerization degree of lignin along the incubation time. Next, using rheological characteristics as a response function, the Kraft lignin amount and incubation time were optimized to get the best characteristics of functionalized Kraft lignin to be used as a thickener in castor oil oleogels. In both cases, response surface methodology (RSM) with a factorial design 23 was applied. The results obtained demonstrated that Kraft lignin was oxidized by recombinant laccase from S. ipomoeae (SilA) increasing its reactivity and, as consequence, the molecular weight average. It was estimated that the highest polymerization occurred with a Kraft lignin concentration of 1.25 g/L and an incubation time of 24.0 min. Moreover, the maximum values of the "plateau modulus"for the oleogels within the limits of the studied region were reached with 66.6 g/L of Kraft lignin and a reaction time of 1.98 h. In conclusion, eco-friendly oleogels obtained in this work fulfil the industrial requirements concerning their rheological properties to be considered as an efficient and biodegradable alternative to traditional lubricants containing lithium as the thickener.

This study has developed an improved and fast microwave-assisted procedure for extraction of high yields of natural antioxidants from artichoke leaves dust. The material is derived as an abundant residue remained after processing for the industrial tea blends preparation, having no commercial value. A key factors for optimization of the total polyphenolic (TPC) and flavonoid content (TFC) and antioxidant activities have been determined by using single factor experiments along with a response surface methodology. The optimal conditions for maximizing the combination of TPC/TFC and antioxidant activity were obtained as follows: ethanol concentration 67.81%, extraction time 50 s, liquid/solid ratio 41.78 mL/g, microwave power 180 W, whereas the corresponding responses resulted in: TPC − 205.59 ± 7.30 mg GAE/g dw, TFC − 79.75 ± 1.12 mg QE/g dw, and FRAP −1008.14 ± 37.15 mmolFe2+/g dw. Only 14.7 µg/mL of the extract concentration is required to inhibit 50% of DPPH free radicals. A comparative study confirmed that the proposed procedure yielded higher TPC, TFC and antioxidant activities than available extraction methods. It highlights a several fold reduced extraction time, caring an eco-friendly principle for obtaining of antioxidants from industrial, medicinal crop residues, which would be further easily valorized in food and pharmaceutical industry.

In this research, a numerical investigation is done on the effect of employing the new combined vortex generators, the twisted tape turbulator and Al2O3-H2O nanofluid as the involved base fluid. Such study is carried out on the behavior of the heat transfer rate and the pressure drop of a double pipe heat exchanger. Accordingly, the response surface methodology (RSM) grounded on the central composite design (CCD) is used for acquiring the optimized geometry of the combined vortex generator and twisted tape turbulator. In order to have the maximum Nusselt number and minimum friction factor, twenty cases with different pitches ratio Pil=0.09-0.18, angles (θ=0-30°) and Reynolds numbers (Re = 5000-20000) are examined. The Results show that the pitch ratio has a predominant effect on the Nusselt number and the friction factor, which causes an efficiency increase up to five times compared to the original one. In addition, by decreasing the angle of the vortex generators in the new combined turbulator, both Nusselt number and the friction factor are increased., QC 20200617

Recently, a series of new photocatalysts have been developed for to combat diverse bio-recalcitrant contaminants and the inactivation of bacteria. Modeling photocatalytic processes is important to assess these materials, and to understand and optimize their performance. In this study, the recent literature is critically reviewed and analyzed to identify and compare methods of modeling photocatalytic performance. The Langmuir–Hinshelwood model (L-H) has been used in many studies to rationalize the degradation kinetics of single contaminants because it is the simplest model including both the adsorption equilibrium and degradation rates. Other studies report the development of more sophisticated variants of the L-H model that include the rates of catalyst excitation, recombination of electron-hole pairs, production of reactive oxygen species (ROS), and formation of by-products. Modified Chick-Watson (C[sbnd]W) and Hom models have been used by many researchers to include lag phases of bacteria in the description of disinfection kinetics. Artificial neural networks (ANNs) have been used to analyze the effects of operational conditions on photocatalyst performance. Moreover, response surface methodology (RSM) has been employed for experimental design, and optimization of operational conditions. We have reviewed and analyzed all available articles that model photocatalytic activity towards water pollution, summarized and put them in context, and recommended future research directions.

Mechanical features of the Cu coatings produced by the pulsating current (PC) regime on Si(111) substrate have been investigated. The Cu coatings were electrodeposited by varying duty cycle (15-50 %) and keeping the current density amplitude constant (100 mA cm(-2)), and by keeping duty cycle constant (50 %) but varying the current density amplitude value (80-120 mA cm(-2)). The scanning electron microscopy (SEM) and optical microscopy (OM) techniques showed that morphology of the coatings changed with increasing the duty cycle from those with large and well defined grains to uniform and compact fine-grained coatings. The Vickers microindentation technique was used for an examination of hardness applying the Chen-Gao (C-G) composite hardness model and indentation creep features of the Cu coatings. The obtained values of hardness for the Cu coatings on Si(111) in the 0.9069-1.5079 GPa range indicated the successful implementation of the C-G model for this "soft film on hard substrate" composite system. The obtained stress exponents ranging from 2.79 to 5.29 indicated that creep mechanism changed from grain boundary sliding to both dislocation climbs and dislocation creep with decreasing duty cycle values. The maximum hardness and minimum stress exponent was obtained for the fine-grained Cu coating produced with a duty cycle of 50 % and the current density amplitude of 100 mA cm(-2), indicating that its plastic deformation during microindentation was primarily caused by grain boundary sliding. Optimization of process formation and mechanical features of the Cu coatings was made using Response Surface Methodology (RSM), and error of 3.2 % showed a good agreement between predicted and measured values.

In this work, the optimization of synthesis of terpolymer monolith based on glycidyl methacrylate (GMA), ethylene glycol dimethacrylate (EGDMA) and additional cross-linkers: trimethylolpropanetriacrylate (TMPTA) or triethylene glycol dimethacrylate (TEGDMA) was performed. Moreover, novel vinyl functionalized cross-linkable polymers: ethanolamine (EA)/methacryloyl (MAC) modified poly (methyl methacrylate) (PMMA), and hydrolyzed poly (ethylene-co-vinyl acetate) copolymer (EVOH) modified with MAC either directly or via ethyl malonyl chloride/EA bridging group (m-EVA) were used as cross-linkable polymer to improve mechanical/elastic properties of the obtained monoliths. Optimization procedure, performed applying response surface methodology (RSM), was focused on the production of materials with improved dimensional stability/integrity and porosity with abundance of epoxide groups capable for immobilization of lipase from Candida rugosa (CRL). Structural characterization of the synthesized monoliths was determined using FTIR, Raman and H-1 NMR spectroscopies, while morphology/porosity was determined by SEM technique and image analysis; and mechanical properties by diametral compression testing. The most potential monolith containing m-EVA polymeric cross-linker, i.e. GMA/EGDMA/TEGDMA/m-EVA monolith, was used as CRL carrier in a two-step immobilization process. Enzyme loading and the activity of obtained preparations for various initial enzyme concentrations were monitored after 4 and 48 h of immobilization. The resulting catalysts show high potency in biocatalytic reactions with the highest percentage of retained initial lipase activity of 64.5%.

Mechanical features of the Cu coatings produced by the pulsating current (PC) regime on Si(111) substrate have been investigated. The Cu coatings were electrodeposited by varying duty cycle (15-50 %) and keeping the current density amplitude constant (100 mA cm(-2)), and by keeping duty cycle constant (50 %) but varying the current density amplitude value (80-120 mA cm(-2)). The scanning electron microscopy (SEM) and optical microscopy (OM) techniques showed that morphology of the coatings changed with increasing the duty cycle from those with large and well defined grains to uniform and compact fine-grained coatings. The Vickers microindentation technique was used for an examination of hardness applying the Chen-Gao (C-G) composite hardness model and indentation creep features of the Cu coatings. The obtained values of hardness for the Cu coatings on Si(111) in the 0.9069-1.5079 GPa range indicated the successful implementation of the C-G model for this "soft film on hard substrate" composite system. The obtained stress exponents ranging from 2.79 to 5.29 indicated that creep mechanism changed from grain boundary sliding to both dislocation climbs and dislocation creep with decreasing duty cycle values. The maximum hardness and minimum stress exponent was obtained for the fine-grained Cu coating produced with a duty cycle of 50 % and the current density amplitude of 100 mA cm(-2), indicating that its plastic deformation during microindentation was primarily caused by grain boundary sliding. Optimization of process formation and mechanical features of the Cu coatings was made using Response Surface Methodology (RSM), and error of 3.2 % showed a good agreement between predicted and measured values.

Mechanical features of the Cu coatings produced by the pulsating current (PC) regime on Si(111) substrate have been investigated. The Cu coatings were electrodeposited by varying duty cycle (15−50 %) and keeping the current density amplitude constant (100 mA cm−2), and by keeping duty cycle constant (50 %) but varying the current density amplitude value (80−120 mA cm−2). The scanning electron microscopy (SEM) and optical microscopy (OM) techniques showed that morphology of the coatings changed with increasing the duty cycle from those with large and well defined grains to uniform and compact fine-grained coatings. The Vickers microindentation technique was used for an examination of hardness applying the Chen-Gao (C-G) composite hardness model and indentation creep features of the Cu coatings. The obtained values of hardness for the Cu coatings on Si(111) in the 0.9069−1.5079 GPa range indicated the successful implementation of the C-G model for this "soft film on hard substrate" composite system. The obtained stress exponents ranging from 2.79 to 5.29 indicated that creep mechanism changed from grain boundary sliding to both dislocation climbs and dislocation creep with decreasing duty cycle values. The maximum hardness and minimum stress exponent was obtained for the fine-grained Cu coating produced with a duty cycle of 50 % and the current density amplitude of 100 mA cm-2, indicating that its plastic deformation during microindentation was primarily caused by grain boundary sliding. Optimization of process formation and mechanical features of the Cu coatings was made using Response Surface Methodology (RSM), and error of 3.2 % showed a good agreement between predicted and measured values.

Perennial plant Gentiana lutea L. is used worldwide for the preparation of pharmaceutical and food products. Health benefits of G. lutea roots are associated with the presence of major bitter-tasting secoiridoid gentiopicroside and xanthone isogentisin. The aim was to optimize the heat-assisted extraction of gentipicroside (GP), isogentisin (ISG) and total phenolics (TP) from G. lutea roots and develop models with high accuracy and prediction capacity by response surface methodology (RSM) and artificial neural networks (ANN). Extracts were prepared according to central composite design. Significant independent variables which were previously identified by Plackett-Burman screening design were varied at five levels - temperature (20−80 °C), time (8−180 min), solid-to-solvent ratio (1:10−1:50) and ethanol concentration (10–70 %). Contents of GP, ISG (by HPLC-DAD) and TP (by Folin–Ciocalteu method) were analyzed. The optimal conditions for the extraction were temperature of 65 °C, time of 129.08 min, solid-to-solvent ratio of 1:40, and ethanol concentration 49.33 %. Under these conditions, experimentally obtained results for GP (18.03 mg/g dw), ISG (8.15 mg/g dw) and TP (17.46 mg of gallic acid equivalents/g dw) content were in agreement with the values predicted by RSM and ANN. Comparison of models through the coefficient of determination (R2) and the root mean square error (RMSE) showed that ANN approach was superior to RSM in predicting and modelling GP, ISG and TP content, simultaneously. Effective heat-assisted extraction method for the extraction of GP, ISG and TP from the roots of G. lutea was designed, and models with high accuracy and good prediction capacity were developed.

Recently, a series of new photocatalysts have been developed for to combat diverse bio-recalcitrant contaminants and the inactivation of bacteria. Modeling photocatalytic processes is important to assess these materials, and to understand and optimize their performance. In this study, the recent literature is critically reviewed and analyzed to identify and compare methods of modeling photocatalytic performance. The Langmuir–Hinshelwood model (L-H) has been used in many studies to rationalize the degradation kinetics of single contaminants because it is the simplest model including both the adsorption equilibrium and degradation rates. Other studies report the development of more sophisticated variants of the L-H model that include the rates of catalyst excitation, recombination of electron-hole pairs, production of reactive oxygen species (ROS), and formation of by-products. Modified Chick-Watson (C[sbnd]W) and Hom models have been used by many researchers to include lag phases of bacteria in the description of disinfection kinetics. Artificial neural networks (ANNs) have been used to analyze the effects of operational conditions on photocatalyst performance. Moreover, response surface methodology (RSM) has been employed for experimental design, and optimization of operational conditions. We have reviewed and analyzed all available articles that model photocatalytic activity towards water pollution, summarized and put them in context, and recommended future research directions.

Mechanical features of the Cu coatings produced by the pulsating current (PC) regime on Si(111) substrate have been investigated. The Cu coatings were electrodeposited by varying duty cycle (15-50 %) and keeping the current density amplitude constant (100 mA cm(-2)), and by keeping duty cycle constant (50 %) but varying the current density amplitude value (80-120 mA cm(-2)). The scanning electron microscopy (SEM) and optical microscopy (OM) techniques showed that morphology of the coatings changed with increasing the duty cycle from those with large and well defined grains to uniform and compact fine-grained coatings. The Vickers microindentation technique was used for an examination of hardness applying the Chen-Gao (C-G) composite hardness model and indentation creep features of the Cu coatings. The obtained values of hardness for the Cu coatings on Si(111) in the 0.9069-1.5079 GPa range indicated the successful implementation of the C-G model for this "soft film on hard substrate" composite system. The obtained stress exponents ranging from 2.79 to 5.29 indicated that creep mechanism changed from grain boundary sliding to both dislocation climbs and dislocation creep with decreasing duty cycle values. The maximum hardness and minimum stress exponent was obtained for the fine-grained Cu coating produced with a duty cycle of 50 % and the current density amplitude of 100 mA cm(-2), indicating that its plastic deformation during microindentation was primarily caused by grain boundary sliding. Optimization of process formation and mechanical features of the Cu coatings was made using Response Surface Methodology (RSM), and error of 3.2 % showed a good agreement between predicted and measured values.

In this work, the optimization of synthesis of terpolymer monolith based on glycidyl methacrylate (GMA), ethylene glycol dimethacrylate (EGDMA) and additional cross-linkers: trimethylolpropanetriacrylate (TMPTA) or triethylene glycol dimethacrylate (TEGDMA) was performed. Moreover, novel vinyl functionalized cross-linkable polymers: ethanolamine (EA)/methacryloyl (MAC) modified poly (methyl methacrylate) (PMMA), and hydrolyzed poly (ethylene-co-vinyl acetate) copolymer (EVOH) modified with MAC either directly or via ethyl malonyl chloride/EA bridging group (m-EVA) were used as cross-linkable polymer to improve mechanical/elastic properties of the obtained monoliths. Optimization procedure, performed applying response surface methodology (RSM), was focused on the production of materials with improved dimensional stability/integrity and porosity with abundance of epoxide groups capable for immobilization of lipase from Candida rugosa (CRL). Structural characterization of the synthesized monoliths was determined using FTIR, Raman and H-1 NMR spectroscopies, while morphology/porosity was determined by SEM technique and image analysis; and mechanical properties by diametral compression testing. The most potential monolith containing m-EVA polymeric cross-linker, i.e. GMA/EGDMA/TEGDMA/m-EVA monolith, was used as CRL carrier in a two-step immobilization process. Enzyme loading and the activity of obtained preparations for various initial enzyme concentrations were monitored after 4 and 48 h of immobilization. The resulting catalysts show high potency in biocatalytic reactions with the highest percentage of retained initial lipase activity of 64.5%.

Mechanical features of the Cu coatings produced by the pulsating current (PC) regime on Si(111) substrate have been investigated. The Cu coatings were electrodeposited by varying duty cycle (15-50 %) and keeping the current density amplitude constant (100 mA cm(-2)), and by keeping duty cycle constant (50 %) but varying the current density amplitude value (80-120 mA cm(-2)). The scanning electron microscopy (SEM) and optical microscopy (OM) techniques showed that morphology of the coatings changed with increasing the duty cycle from those with large and well defined grains to uniform and compact fine-grained coatings. The Vickers microindentation technique was used for an examination of hardness applying the Chen-Gao (C-G) composite hardness model and indentation creep features of the Cu coatings. The obtained values of hardness for the Cu coatings on Si(111) in the 0.9069-1.5079 GPa range indicated the successful implementation of the C-G model for this "soft film on hard substrate" composite system. The obtained stress exponents ranging from 2.79 to 5.29 indicated that creep mechanism changed from grain boundary sliding to both dislocation climbs and dislocation creep with decreasing duty cycle values. The maximum hardness and minimum stress exponent was obtained for the fine-grained Cu coating produced with a duty cycle of 50 % and the current density amplitude of 100 mA cm(-2), indicating that its plastic deformation during microindentation was primarily caused by grain boundary sliding. Optimization of process formation and mechanical features of the Cu coatings was made using Response Surface Methodology (RSM), and error of 3.2 % showed a good agreement between predicted and measured values.

Mechanical features of the Cu coatings produced by the pulsating current (PC) regime on Si(111) substrate have been investigated. The Cu coatings were electrodeposited by varying duty cycle (15−50 %) and keeping the current density amplitude constant (100 mA cm−2), and by keeping duty cycle constant (50 %) but varying the current density amplitude value (80−120 mA cm−2). The scanning electron microscopy (SEM) and optical microscopy (OM) techniques showed that morphology of the coatings changed with increasing the duty cycle from those with large and well defined grains to uniform and compact fine-grained coatings. The Vickers microindentation technique was used for an examination of hardness applying the Chen-Gao (C-G) composite hardness model and indentation creep features of the Cu coatings. The obtained values of hardness for the Cu coatings on Si(111) in the 0.9069−1.5079 GPa range indicated the successful implementation of the C-G model for this "soft film on hard substrate" composite system. The obtained stress exponents ranging from 2.79 to 5.29 indicated that creep mechanism changed from grain boundary sliding to both dislocation climbs and dislocation creep with decreasing duty cycle values. The maximum hardness and minimum stress exponent was obtained for the fine-grained Cu coating produced with a duty cycle of 50 % and the current density amplitude of 100 mA cm-2, indicating that its plastic deformation during microindentation was primarily caused by grain boundary sliding. Optimization of process formation and mechanical features of the Cu coatings was made using Response Surface Methodology (RSM), and error of 3.2 % showed a good agreement between predicted and measured values.

BACKGROUND Some liquid industrial wastes are rich in sulfur (S), nitrogen (N) and organic matter, causing eutrophication of lakes and rivers. These wastes also are highly toxic to aquatic organisms and pose serious health problems. Biological N removal is performed by denitrification. Heterotrophic denitrifiers oxidize organic matter to CO2 gas and reduce nitrate (NO3−) to N2 gas, whereas autotrophic denitrifiers oxidize reduced S compounds by reducing nitrate. Thus, a simultaneous denitrification process will allow for the removal of all these elements. RESULTS A response surface methodology (RSM) was used to analyze the effects of the ratios heterotrophic:autotrophic bacteria (H:A, 0.2–1.9), the molar Ac−(Acetate):NO3− (0.2–1.05) and thiosulfate (S2O32−):NO3− (0.15–1.1) on the denitrification process. The highest concentrations of sulfate were obtained with H:A = 0.2; Ac−: NO3− = 1.05 and S2O32−:NO3− = 0.91. CONCLUSION High NO3− (average 95.0 ± 3.3%) removals were obtained in all experiments, the optimal values predicted by the RSM were obtained at H:A = 0.54, Ac−:NO3− = 1.05 and S2O32−:NO3− = 0.41. When analyzing the removal of Ac−, the recommended optimal operating values were: Ac−:NO3− = 1.05; H:A = 0.37 and S2O32−:NO3− = 0.8–0.9. © 2019 Society of Chemical Industry

In this work, the optimization of synthesis of terpolymer monolith based on glycidyl methacrylate (GMA), ethylene glycol dimethacrylate (EGDMA) and additional cross-linkers: trimethylolpropanetriacrylate (TMPTA) or triethylene glycol dimethacrylate (TEGDMA) was performed. Moreover, novel vinyl functionalized cross-linkable polymers: ethanolamine (EA)/methacryloyl (MAC) modified poly (methyl methacrylate) (PMMA), and hydrolyzed poly (ethylene-co-vinyl acetate) copolymer (EVOH) modified with MAC either directly or via ethyl malonyl chloride/EA bridging group (m-EVA) were used as cross-linkable polymer to improve mechanical/elastic properties of the obtained monoliths. Optimization procedure, performed applying response surface methodology (RSM), was focused on the production of materials with improved dimensional stability/integrity and porosity with abundance of epoxide groups capable for immobilization of lipase from Candida rugosa (CRL). Structural characterization of the synthesized monoliths was determined using FTIR, Raman and H-1 NMR spectroscopies, while morphology/porosity was determined by SEM technique and image analysis; and mechanical properties by diametral compression testing. The most potential monolith containing m-EVA polymeric cross-linker, i.e. GMA/EGDMA/TEGDMA/m-EVA monolith, was used as CRL carrier in a two-step immobilization process. Enzyme loading and the activity of obtained preparations for various initial enzyme concentrations were monitored after 4 and 48 h of immobilization. The resulting catalysts show high potency in biocatalytic reactions with the highest percentage of retained initial lipase activity of 64.5%.

[EN] Ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE) of bioactive compounds, peels from Opuntia engelmannii cultivar (cv.) Valencia were optimized by response surface methodology. Randomized extraction runs were performed for each of the technologies employed in order to build effective models with maximum (bioactive molecules content and yield) and minimum (antioxidant activity) responses. A 5-level, 4-factor central composite design was used to obtain target responses as a function of extraction time (t), solid to liquid ratio (S/L), methanol concentration (metOH), and temperature (T). Specific response optimization for each technology was analyzed, discussed, and general optimization from all the responses together was also gather. The optimum values for each factor were: t = 2.5 and 1.4 min, S/L = 5 and 5 g/L, metOH = 34.6 and 0% of methanol and T = 30 and 36.6 °C, achieving maximum responses of 201.6 and 132.9 mg of betalains/g, 13.9 and 8.0 mg of phenolic acids/g, 2.4 and 1.5 mg of flavonoids/g, 71.8% and 79.1% of extractable solid and IC50 values for the antioxidant activity of 2.9 and 3.6, for UAE and MAE, respectively. The present study suggested UAE as the best extraction system, in order to maximize recovery of bioactive compounds with a high antioxidant activity.

[EN] Ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE) of bioactive compounds, peels from Opuntia engelmannii cultivar (cv.) Valencia were optimized by response surface methodology. Randomized extraction runs were performed for each of the technologies employed in order to build effective models with maximum (bioactive molecules content and yield) and minimum (antioxidant activity) responses. A 5-level, 4-factor central composite design was used to obtain target responses as a function of extraction time (t), solid to liquid ratio (S/L), methanol concentration (metOH), and temperature (T). Specific response optimization for each technology was analyzed, discussed, and general optimization from all the responses together was also gather. The optimum values for each factor were: t = 2.5 and 1.4 min, S/L = 5 and 5 g/L, metOH = 34.6 and 0% of methanol and T = 30 and 36.6 °C, achieving maximum responses of 201.6 and 132.9 mg of betalains/g, 13.9 and 8.0 mg of phenolic acids/g, 2.4 and 1.5 mg of flavonoids/g, 71.8% and 79.1% of extractable solid and IC50 values for the antioxidant activity of 2.9 and 3.6, for UAE and MAE, respectively. The present study suggested UAE as the best extraction system, in order to maximize recovery of bioactive compounds with a high antioxidant activity.

The use of the microwave-activated sugar beet pulp as an alternative adsorbent material in combination with biological processes has been applied for the colored wastewater treatment. The maximum adsorption capacity of the crystal violet dye has been achieved relatively fast, during 315 s, with no dependence of the pH, when the adsorbent mass was 15 and 0.2 g/L of the initial dye concentration. The adsorption equilibrium data fully complied with the Temkin isotherm. The afterward biological decontamination of the adsorbed dye was related to the biodegradable potential of Streptomyces microflavus CKS6 cells. The microorganism revealed strong affinity toward the dye and minimal nutritional requirements for the metabolic activity expressions. Total dye decomposition occurred after 9 h, whereby lignin peroxidase enzyme has been recognized to be mainly involved in the process. According to the phytotoxicity analysis, no harmful residues were found in the decolorized working medium.

A neural network model of key process parameters and forming quality is developed based on training samples which are obtained from the orthogonal experiment and the finite element numerical simulation. Optimization of the process parameters is conducted using the genetic algorithm (GA). The experimental results have shown that a surface model of the neural network can describe the nonlinear implicit relationship between the parameters of the power spinning process: the wall margin and amount of expansion. It has been found that the process of determining spinning technological parameters can be accelerated using the optimization method developed based on the BP neural network and the genetic algorithm used for the process parameters of power spinning formation. It is undoubtedly beneficial towards engineering applications.

The use of the microwave-activated sugar beet pulp as an alternative adsorbent material in combination with biological processes has been applied for the colored wastewater treatment. The maximum adsorption capacity of the crystal violet dye has been achieved relatively fast, during 315 s, with no dependence of the pH, when the adsorbent mass was 15 and 0.2 g/L of the initial dye concentration. The adsorption equilibrium data fully complied with the Temkin isotherm. The afterward biological decontamination of the adsorbed dye was related to the biodegradable potential of Streptomyces microflavus CKS6 cells. The microorganism revealed strong affinity toward the dye and minimal nutritional requirements for the metabolic activity expressions. Total dye decomposition occurred after 9 h, whereby lignin peroxidase enzyme has been recognized to be mainly involved in the process. According to the phytotoxicity analysis, no harmful residues were found in the decolorized working medium.

The present study compares the performances of the regression models developed by the response surface methodology combined with the full factorial, Box-Behnken or face central composite designs applied for the ultrasound-assisted KOH-catalyzed methanolysis of sunflower oil. While all models led to similar optimal reaction conditions, the models based on the simpler designs had the smaller corrected Akaike information criterion values, the insignificant lack of fit and the more favorable statistical criteria than the model based on the full factorial design. Including fewer experiments, the Box-Behnken design can be recommended for the optimization of ultrasound-assisted biodiesel production processes., U radu se porede performanse regresionih modela razvijenih na osnovu kombinovanja metodologije površine odziva sa punim faktorijelnim, Boks-Benken-ovim ili centralnim kompozitnim planom kada se primene na ultrazvukom podržanu bazno-katalizovanu metanolizu suncokretovog ulja. Iako su svi modeli dali slične optimalne uslove reakcije, modeli zasnovani na jednostavnijim planovima imali su manje vrednosti Akaike-ovog informacionog kriterijuma, neznačajnu vrednost odstupanja od modela i povoljnije statističke kriterijume u odnosu na model zasnovan na punom faktorijelnim planu. Boks-Benken-ov plan, koji zahteva manji broj eksperimenata, može da se preporuči za optimizaciju proizvodnje biodizela u ultrazvučnom reaktoru.

This research focused on obtaining eicosapentaenoic acid (EPA, 20:5 n-3) and docosahexaenoic acid (DHA, 22:6 n-3) (EPA+DHA) concentrates from refined commercial salmon oil (RCSO). Independent variables of the complexation process were optimized by means of the application of response surface methodology (RSM) in order to obtain the maximum content of such fatty acids (FAs). As a result of employing the optimized conditions for all the variables (6.0, urea:FA content ratio; −18.0 °C, crystallization temperature; 14.80 h, crystallization time; 500 rpm, stirring speed), high contents of EPA and DHA could be obtained from RCSO, achieving increases of 4.1 and 7.9 times in the concentrate, with values of 31.20 and 49.31 g/100 g total FA, respectively. Furthermore, a 5.8-time increase was observed for the EPA + DHA content, which increased from 13.78 to 80.51 g/100 g total FA. It is concluded that RCSO can be transformed into a profitable source of EPA and DHA (EPA+DHA), thus leading to a product with higher commercial value.

In the present study, the microstructural and mechanical properties of laser beam-welded thin sheet twinning-induced plasticity (TWIP) steel were investigated. The pulsed neodymium: yttrium-aluminum-garnet (Nd: YAG) laser beam welding process parameters were modeled and optimized based on experimental data and statistical analysis using response surface methodology (RSM) technique. Process parameters range, i.e. the power input (2000–3000 W), welding speed (0.2–1 mm/min), and spot size (0.3–0.7 mm) were selected properly in order to obtain the desired mechanical properties. Main effects of each factor along with interaction effect with other factors were determined quantitatively. The predicted and actual values of the mechanical properties compared using analysis of variance (ANOVA) in order to verify the adequacy of the developed model. Optimal laser beam welding parameters were identified as the power input, welding speed and spot size of 2586 W, 0.53 mm/min, and 0.48 mm, respectively. Using parameters in the optimal conditions, a welding joint with tensile load of 2001 N (% 94 strength of the base metal) was obtained. In addition, the welding zone with an average grain size coarser than the one for the base metal and a random texture was identified., PP-check JTH 2019 embargo 24 / EE

Haloferax mediterranei produces C50 carotenoids that have strong antioxidant properties. The response surface methodology (RSM) tool helps to accurately analyze the most suitable conditions to maximize C50 carotenoids production by haloarchaea. The effects of temperature (15–50 °C), pH (4−10), and salinity (5–28% NaCl (w/v)) on the growth and carotenoid content of H. mediterranei were analyzed using the RSM approach. Growth was determined by measuring the turbidity at 600 nm. To determine the carotenoid content, harvested cells were lysed by freeze/thawing, then re-suspended in acetone and the total carotenoid content determined by measuring the absorbance at 494 nm. The analysis of carotenoids was performed by an HPLC system coupled with mass spectrometry. The results indicated the theoretical optimal conditions of 36.51 or 36.81 °C, pH of 8.20 or 8.96, and 15.01% or 12.03% (w/v) salinity for the growth of haloarchaea (OD600 = 12.5 ± 0.64) and production of total carotenoids (3.34 ± 0.29 mg/L), respectively. These conditions were validated experimentally for growth (OD600 = 13.72 ± 0.98) and carotenoid production (3.74 ± 0.20 mg/L). The carotenoid profile showed four isomers of bacterioruberin (89.13%). Our findings suggest that the RSM approach is highly useful for determining optimal conditions for large-scale production of bacterioruberin by haloarchaea.

Haloferax mediterranei produces C50 carotenoids that have strong antioxidant properties. The response surface methodology (RSM) tool helps to accurately analyze the most suitable conditions to maximize C50 carotenoids production by haloarchaea. The effects of temperature (15–50 °C), pH (4−10), and salinity (5–28% NaCl (w/v)) on the growth and carotenoid content of H. mediterranei were analyzed using the RSM approach. Growth was determined by measuring the turbidity at 600 nm. To determine the carotenoid content, harvested cells were lysed by freeze/thawing, then re-suspended in acetone and the total carotenoid content determined by measuring the absorbance at 494 nm. The analysis of carotenoids was performed by an HPLC system coupled with mass spectrometry. The results indicated the theoretical optimal conditions of 36.51 or 36.81 °C, pH of 8.20 or 8.96, and 15.01% or 12.03% (w/v) salinity for the growth of haloarchaea (OD600 = 12.5 ± 0.64) and production of total carotenoids (3.34 ± 0.29 mg/L), respectively. These conditions were validated experimentally for growth (OD600 = 13.72 ± 0.98) and carotenoid production (3.74 ± 0.20 mg/L). The carotenoid profile showed four isomers of bacterioruberin (89.13%). Our findings suggest that the RSM approach is highly useful for determining optimal conditions for large-scale production of bacterioruberin by haloarchaea.

The aim of this study was to develop dextran-based edible films plasticized by sorbitol. In order to optimise the film-forming formulation, response surface methodology was used. The influence of dextran and sorbitol concentration on the mechanical and water vapour barrier properties of obtained films was investigated. The results showed that both parameters exhibited significant effect on the water vapour permeability of a film. Both dextran and sorbitol concentration had significant influence on tensile strength and elongation at break, whereas only sorbitol concentration had significant effect on Young's modulus. After optimisation by desirability approach, it was found that a film made of 3.40 wt% of dextran and 20.43 wt% of sorbitol showed the lowest water vapour permeability and the highest tensile strength and elasticity.

Haloferax mediterranei produces C50 carotenoids that have strong antioxidant properties. The response surface methodology (RSM) tool helps to accurately analyze the most suitable conditions to maximize C50 carotenoids production by haloarchaea. The effects of temperature (15–50 °C), pH (4−10), and salinity (5–28% NaCl (w/v)) on the growth and carotenoid content of H. mediterranei were analyzed using the RSM approach. Growth was determined by measuring the turbidity at 600 nm. To determine the carotenoid content, harvested cells were lysed by freeze/thawing, then re-suspended in acetone and the total carotenoid content determined by measuring the absorbance at 494 nm. The analysis of carotenoids was performed by an HPLC system coupled with mass spectrometry. The results indicated the theoretical optimal conditions of 36.51 or 36.81 °C, pH of 8.20 or 8.96, and 15.01% or 12.03% (w/v) salinity for the growth of haloarchaea (OD600 = 12.5 ± 0.64) and production of total carotenoids (3.34 ± 0.29 mg/L), respectively. These conditions were validated experimentally for growth (OD600 = 13.72 ± 0.98) and carotenoid production (3.74 ± 0.20 mg/L). The carotenoid profile showed four isomers of bacterioruberin (89.13%). Our findings suggest that the RSM approach is highly useful for determining optimal conditions for large-scale production of bacterioruberin by haloarchaea.

The production of a desired product needs an effective use of the experimental model. The present study proposes an extreme learning machine (ELM) and a support vector machine (SVM) integrated with the response surface methodology (RSM) to solve the complexity in optimization and prediction of the ethyl ester and methyl ester production process. The novel hybrid models of ELM-RSM and ELM-SVM are further used as a case study to estimate the yield of methyl and ethyl esters through a trans-esterification process from waste cooking oil (WCO) based on American Society for Testing and Materials (ASTM) standards. The results of the prediction phase were also compared with artificial neural networks (ANNs) and adaptive neuro-fuzzy inference system (ANFIS), which were recently developed by the second author of this study. Based on the results, an ELM with a correlation coefficient of 0.9815 and 0.9863 for methyl and ethyl esters, respectively, had a high estimation capability compared with that for SVM, ANNs, and ANFIS. Accordingly, the maximum production yield was obtained in the case of using ELM-RSM of 96.86% for ethyl ester at a temperature of 68.48 °C, a catalyst value of 1.15 wt. %, mixing intensity of 650.07 rpm, and an alcohol to oil molar ratio (A/O) of 5.77; for methyl ester, the production yield was 98.46% at a temperature of 67.62 °C, a catalyst value of 1.1 wt. %, mixing intensity of 709.42 rpm, and an A/O of 6.09. Therefore, ELM-RSM increased the production yield by 3.6% for ethyl ester and 3.1% for methyl ester, compared with those for the experimental data.

Haloferax mediterranei produces C50 carotenoids that have strong antioxidant properties. The response surface methodology (RSM) tool helps to accurately analyze the most suitable conditions to maximize C50 carotenoids production by haloarchaea. The effects of temperature (15–50 °C), pH (4−10), and salinity (5–28% NaCl (w/v)) on the growth and carotenoid content of H. mediterranei were analyzed using the RSM approach. Growth was determined by measuring the turbidity at 600 nm. To determine the carotenoid content, harvested cells were lysed by freeze/thawing, then re-suspended in acetone and the total carotenoid content determined by measuring the absorbance at 494 nm. The analysis of carotenoids was performed by an HPLC system coupled with mass spectrometry. The results indicated the theoretical optimal conditions of 36.51 or 36.81 °C, pH of 8.20 or 8.96, and 15.01% or 12.03% (w/v) salinity for the growth of haloarchaea (OD600 = 12.5 ± 0.64) and production of total carotenoids (3.34 ± 0.29 mg/L), respectively. These conditions were validated experimentally for growth (OD600 = 13.72 ± 0.98) and carotenoid production (3.74 ± 0.20 mg/L). The carotenoid profile showed four isomers of bacterioruberin (89.13%). Our findings suggest that the RSM approach is highly useful for determining optimal conditions for large-scale production of bacterioruberin by haloarchaea.

Haloferax mediterranei produces C50 carotenoids that have strong antioxidant properties. The response surface methodology (RSM) tool helps to accurately analyze the most suitable conditions to maximize C50 carotenoids production by haloarchaea. The effects of temperature (15–50 °C), pH (4−10), and salinity (5–28% NaCl (w/v)) on the growth and carotenoid content of H. mediterranei were analyzed using the RSM approach. Growth was determined by measuring the turbidity at 600 nm. To determine the carotenoid content, harvested cells were lysed by freeze/thawing, then re-suspended in acetone and the total carotenoid content determined by measuring the absorbance at 494 nm. The analysis of carotenoids was performed by an HPLC system coupled with mass spectrometry. The results indicated the theoretical optimal conditions of 36.51 or 36.81 °C, pH of 8.20 or 8.96, and 15.01% or 12.03% (w/v) salinity for the growth of haloarchaea (OD600 = 12.5 ± 0.64) and production of total carotenoids (3.34 ± 0.29 mg/L), respectively. These conditions were validated experimentally for growth (OD600 = 13.72 ± 0.98) and carotenoid production (3.74 ± 0.20 mg/L). The carotenoid profile showed four isomers of bacterioruberin (89.13%). Our findings suggest that the RSM approach is highly useful for determining optimal conditions for large-scale production of bacterioruberin by haloarchaea.

© 2018. This version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0, Fly ash-based geopolymer binders have been identified as one of the alternatives to the Ordinary Portland Cement (OPC), which qualify the criteria of green construction material. In the process of enhancement of the properties of geopolymer; engineered geopolymer composite (EGC) is a recent development that is classified as the high-performance fiber reinforced geopolymer matrix. The philosophy of the development of EGC is to achieve high compressive strength and ductility. In this paper, statistical models are developed to predict the mechanical and post-cracking properties of EGC using Response Surface Methodology (RSM). In this regard, effects of three principal variables; molarity of sodium hydroxide, sodium silicate to sodium hydroxide ratio, and curing temperature on the properties of fresh and hardened EGC (setting time, compressive strength, elastic modulus, flexural strength, flexural toughness, ductility index, tensile strength, tensile first crack strength and tensile strain capacity) were investigated. All models are found significant because, and the difference between predicted R2 and adjustable R2 was found less than 0.2. The optimized mixture proportion was assessed using multi-objective optimization technique as discussed in the RSM literature. Finally, an experimental program was performed to validate the optimized mixture proportion. The predicted and experimental results were found in a close agreement because the variation between the predicted and the experimental results was obtained less than 5%. The proposed method can be performed for any objective value of the EGC property with desirability almost equal to one, improving the yield, the reliability of the product and the processes., Peer Reviewed, Postprint (author's final draft)

Haloferax mediterranei produces C50 carotenoids that have strong antioxidant properties. The response surface methodology (RSM) tool helps to accurately analyze the most suitable conditions to maximize C50 carotenoids production by haloarchaea. The effects of temperature (15–50 °C), pH (4−10), and salinity (5–28% NaCl (w/v)) on the growth and carotenoid content of H. mediterranei were analyzed using the RSM approach. Growth was determined by measuring the turbidity at 600 nm. To determine the carotenoid content, harvested cells were lysed by freeze/thawing, then re-suspended in acetone and the total carotenoid content determined by measuring the absorbance at 494 nm. The analysis of carotenoids was performed by an HPLC system coupled with mass spectrometry. The results indicated the theoretical optimal conditions of 36.51 or 36.81 °C, pH of 8.20 or 8.96, and 15.01% or 12.03% (w/v) salinity for the growth of haloarchaea (OD600 = 12.5 ± 0.64) and production of total carotenoids (3.34 ± 0.29 mg/L), respectively. These conditions were validated experimentally for growth (OD600 = 13.72 ± 0.98) and carotenoid production (3.74 ± 0.20 mg/L). The carotenoid profile showed four isomers of bacterioruberin (89.13%). Our findings suggest that the RSM approach is highly useful for determining optimal conditions for large-scale production of bacterioruberin by haloarchaea.

Haloferax mediterranei produces C50 carotenoids that have strong antioxidant properties. The response surface methodology (RSM) tool helps to accurately analyze the most suitable conditions to maximize C50 carotenoids production by haloarchaea. The effects of temperature (15–50 °C), pH (4−10), and salinity (5–28% NaCl (w/v)) on the growth and carotenoid content of H. mediterranei were analyzed using the RSM approach. Growth was determined by measuring the turbidity at 600 nm. To determine the carotenoid content, harvested cells were lysed by freeze/thawing, then re-suspended in acetone and the total carotenoid content determined by measuring the absorbance at 494 nm. The analysis of carotenoids was performed by an HPLC system coupled with mass spectrometry. The results indicated the theoretical optimal conditions of 36.51 or 36.81 °C, pH of 8.20 or 8.96, and 15.01% or 12.03% (w/v) salinity for the growth of haloarchaea (OD600 = 12.5 ± 0.64) and production of total carotenoids (3.34 ± 0.29 mg/L), respectively. These conditions were validated experimentally for growth (OD600 = 13.72 ± 0.98) and carotenoid production (3.74 ± 0.20 mg/L). The carotenoid profile showed four isomers of bacterioruberin (89.13%). Our findings suggest that the RSM approach is highly useful for determining optimal conditions for large-scale production of bacterioruberin by haloarchaea.

Haloferax mediterranei produces C50 carotenoids that have strong antioxidant properties. The response surface methodology (RSM) tool helps to accurately analyze the most suitable conditions to maximize C50 carotenoids production by haloarchaea. The effects of temperature (15–50 °C), pH (4−10), and salinity (5–28% NaCl (w/v)) on the growth and carotenoid content of H. mediterranei were analyzed using the RSM approach. Growth was determined by measuring the turbidity at 600 nm. To determine the carotenoid content, harvested cells were lysed by freeze/thawing, then re-suspended in acetone and the total carotenoid content determined by measuring the absorbance at 494 nm. The analysis of carotenoids was performed by an HPLC system coupled with mass spectrometry. The results indicated the theoretical optimal conditions of 36.51 or 36.81 °C, pH of 8.20 or 8.96, and 15.01% or 12.03% (w/v) salinity for the growth of haloarchaea (OD600 = 12.5 ± 0.64) and production of total carotenoids (3.34 ± 0.29 mg/L), respectively. These conditions were validated experimentally for growth (OD600 = 13.72 ± 0.98) and carotenoid production (3.74 ± 0.20 mg/L). The carotenoid profile showed four isomers of bacterioruberin (89.13%). Our findings suggest that the RSM approach is highly useful for determining optimal conditions for large-scale production of bacterioruberin by haloarchaea.

Haloferax mediterranei produces C50 carotenoids that have strong antioxidant properties. The response surface methodology (RSM) tool helps to accurately analyze the most suitable conditions to maximize C50 carotenoids production by haloarchaea. The effects of temperature (15–50 °C), pH (4−10), and salinity (5–28% NaCl (w/v)) on the growth and carotenoid content of H. mediterranei were analyzed using the RSM approach. Growth was determined by measuring the turbidity at 600 nm. To determine the carotenoid content, harvested cells were lysed by freeze/thawing, then re-suspended in acetone and the total carotenoid content determined by measuring the absorbance at 494 nm. The analysis of carotenoids was performed by an HPLC system coupled with mass spectrometry. The results indicated the theoretical optimal conditions of 36.51 or 36.81 °C, pH of 8.20 or 8.96, and 15.01% or 12.03% (w/v) salinity for the growth of haloarchaea (OD600 = 12.5 ± 0.64) and production of total carotenoids (3.34 ± 0.29 mg/L), respectively. These conditions were validated experimentally for growth (OD600 = 13.72 ± 0.98) and carotenoid production (3.74 ± 0.20 mg/L). The carotenoid profile showed four isomers of bacterioruberin (89.13%). Our findings suggest that the RSM approach is highly useful for determining optimal conditions for large-scale production of bacterioruberin by haloarchaea.

The aim of this study was to develop dextran-based edible films plasticized by sorbitol. In order to optimise the film-forming formulation, response surface methodology was used. The influence of dextran and sorbitol concentration on the mechanical and water vapour barrier properties of obtained films was investigated. The results showed that both parameters exhibited significant effect on the water vapour permeability of a film. Both dextran and sorbitol concentration had significant influence on tensile strength and elongation at break, whereas only sorbitol concentration had significant effect on Young's modulus. After optimisation by desirability approach, it was found that a film made of 3.40 wt% of dextran and 20.43 wt% of sorbitol showed the lowest water vapour permeability and the highest tensile strength and elasticity.