Utilization of ramon seeds (Brosimum alicastrum swarts) as a new source material for thermoplastic starch production

The development and characterization of biodegradable polymers deriving from renewable natural sources has attracted much attention. The aim of this work was to partially characterize a thermoplastic starch obtained from the starch of seeds from the ramon tree (TPS‐RS) as an option to substitute thermoplastic starch from corn (TPS‐CS), in some of its applications. At 55% of relative humidity (RH), TPS‐RS had higher tensile strength and deformation than TPS‐CS. X‐ray diffraction analysis showed similar values in residual crystallinity (percentage of crystallinity that remains after plasticization process) in both TPS. The SEM micrographs showed a few remnant granular structures in the TPS‐RS. The FTIR showed a greater intensity in band at 1016 cm^?1 in the TPS‐CS and TPS‐RS in comparison with their corresponding native starch, indicating an increase in the amorphous region after plasticization. The TGA analysis showed greater thermal stability in TPS‐CS (340 °C) compared with TPS‐RS (327 °C). In addition, the glass transition temperature in both TPS was 24 °C. The results obtained represent a starting point to potentialize the use of TPS‐RS instead of TPS‐CS for the development of new biodegradable materials for practical applications in different areas. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44235.     

Application of response surface methodology and central composite rotatable design for modeling and optimization of a multi-gravity separator for chromite concentration

In this study, the application of response surface methodology (RSM) and central composite rotatable design (CCRD) for modeling and optimization of the influence of some operating variables on the performance of a multi-gravity separator (MGS) for chromite concentration is discussed. Three MGS operating variables, namely drum speed, tilt angle, and wash water flow rate were changed during the concentration tests based on CCRD. The range of values of the MGS variables used in the design were a drum speed of 133-217 rpm, tilt angle of 1.6°-8.4°, and wash water flow rate of 1.3-4.7 lpm. A total of 20 concentration tests were conducted using MGS on chromite ore obtained from Kangal/Eskikoy—Turkey.In order to optimize chromite concentration with MGS, mathematical model equations were derived by computer simulation programming applying least squares method using MATLAB 7.1. These equations that are second-order response functions representing concentrate grade and recovery were expressed as functions of three operating parameters of MGS. Predicted values were found to be in good agreement with experimental values (R² values of 0.96 and 0.98 for concentrate grade and recovery, respectively). In order to gain a better understanding of the three variables for optimal MGS performance, the models were presented as 3-D response surface graphs. This study has shown that the RSM and CCRD could efficiently be applied for the modeling of MGS for chromite concentration and it is an economical way of obtaining the maximum amount of information in a short period of time and with the fewest number of experiments.     

Modeling and optimization of the sandwich beam specimen in three-point bending for adhesive bond characterization

Standard tests for adhesive bond characterization suffer for several deficiencies. The simplest specimens to make and test are lap joint geometries (e.g. single, double, symmetric, etc.) that generate complex stress distributions with irregularities and even singularities of the stress state. Those with the stress state closer to pure shear (e.g. napkin ring or Arcan) are difficult to make and require special test fixtures. This paper examines the stress state in the adhesive of a simple beam specimen obtained by bonding two flat plates one upon the other and loading the final sandwich in three-point bending. An elementary theory is used to optimize the specimen for in-situ measurements of either shear strength or shear modulus of the adhesive. The accuracy of the model is validated with finite element analyses, showing good agreement between the analytical and finite element model and also providing suggestions for the best geometry to be adopted for practical implementation of the test.     

Application of response surface methodology to extract yields from stinging nettle under supercritical ethanol conditions

Response surface methodology was employed using a central composite design of experiments to optimize experimental conditions for stinging nettle extract yields under supercritical ethanol conditions. The following independent variables were investigated: extraction temperature, extraction time and plant concentration. The most significant factor was found to be the extraction temperature. A correlation coefficient was estimated to be 0.94, which demonstrates the effectiveness of the model. The values of the parameters in optimized conditions for the stinging nettle extract yield included an extraction temperature of 335 °C, an extraction time of 87 min, and a plant concentration of 9.A subsequent validation experiment was carried out at the optimal conditions. The validation experiment showed that the actual and predicted values for the stinging nettle extract yields were 45.3 and 42.7 wt%, respectively. The stinging nettle extracts consisted of a collection of compounds including fatty acid esters (FAE), phenols, indoles, and nitrogen containing compounds.     

中心组合设计优化铁垫片的化学镀镍磷工艺

采用中心组合设计法研究了化学镀镍过程中的三个作用因子:表面活性剂十二烷基二甲基甜菜碱(BS-12)用量、施镀温度、光亮剂辛基酚聚氧乙烯基醚(OP-10)对镍磷沉积速率的影响,得到了三因子与沉积速率的回归方程以及三因素之间相互作用的响应面图。用电子扫描电镜与X-射线衍射仪分析了表征了镀层形貌与晶型结构。优化结果表明,表面活性剂的用量为4.8 mL,施镀温度为52.8 oC,光亮剂的用量为6.6 mL时,镀速为13.56μm/h,比基础镀液的镀速高13%,且镀层光亮致密。所用的光亮剂与表面活性剂不仅影响镀层的沉积速率,而且改变镀层的相结构与性能。     

Correlation between Physical Properties and Shear Adhesion Strength of Enzymatically Modified Soy Protein-Based Adhesives

This work was to correlate physical properties with adhesion properties of soy protein‐based adhesives. By building such a correlation, the adhesion properties can be predicted by measuring physical properties of soy protein‐based adhesives. In this context, three important physical properties, viscosity, tacky force, and water resistance, were selected to correlate with adhesion strength of enzymatically modified soy protein‐based adhesives (ESP). Response surface methodology, specifically central composite design, was used with three independent variables to prepare ESP: trypsin concentration (X₁), incubation time (X₂), and glutaraldehyde (GA) concentration (X₃). The three physical properties measured were all greatly affected by our three independent variables with significance at the 95 % confidence level. The responses were then correlated with the adhesion properties of ESP. In conclusion, viscosity can be used to predict the dry adhesion strength of ESP based on the coefficient of determination (R²) of 0.8558. In addition, tacky force and water resistance can be used to represent wet adhesion strength of ESP based on R² of 0.7082 and 0.6930, respectively (P < 0.05). This work preliminarily identified the significant physical properties that can predict the adhesion strength of the ESP system crosslinked with GA, but the results need to be further confirmed by another protein modification system to give a generic conclusion.     

Growth of ZnO nanowires on carbon fibers for photocatalytic degradation of methylene blue aqueous solutions: An investigation on the optimization of processing parameters through response surface methodology/central composite design

In this work, effects of hydrothermal (HT) synthesis method parameters, temperature, concentration and growth time, on the formation of zinc oxide nanowire structures on carbon fibers (ZnO NWs/CFs) were evaluated. Morphological, structural, photocatalytic properties were determined through scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV–Visible spectrophotometer. In addition, response surface methodology (RSM) and central composite design (CCD) were applied to optimize the hydrothermal synthesis parameters. The results pointed out that, the change in hydrothermal solution concentration (from 3.2 to 37 mM ZnNO_3·6H₂O) and process time (from 2.6 to 9.2 h) lead to the increase in thickness and decrease in aspect ratio of zinc oxide nanowires. Whereas, the temperature increases from 80 to 130 °C had a minute effect on the structure. ZnO nanowires with zincite structure were obtained for all processing conditions. Finally, photocatalytic activity of ZnO NWs/CFs on the degradation of aqueous methylene blue solution (MB) were recorded comparatively. ZnO NWs/CFs structure exhibited photocatalytic activity in the degradation of methylene blue (MB). The most effective structure was obtained at 120 °C, 30 mM Zn(NO₃)_2·6H₂O and 4 h HT synthesis parameters.     

Design of experiments for statistical modeling and multi-response optimization of nickel electroplating process

The central composite experimental design and response surface methodology have been employed for statistical modeling and analysis of the results dealing with nickel electroplating process. The empirical models developed in terms of design variables (current density J (A/dm²), temperature T (°C) and pH) have been found statistically adequate to describe the process responses, i.e. cathode efficiency Y (%), coating thickness U (μm), brightness V (%) and hardness W (HV). The graphical representations consisted of 2D contour plots and 3D surface plots have been used for exploring and analysis of response surfaces in order to identify the main, quadratic and interaction effects. The multi-response optimization of nickel electroplating process has been carried out by means of desirability function approach. To this end, a genetic algorithm has been used for mathematical optimization of the multi-response problem. The optimization algorithm has conducted to a set of equivalent solutions named Pareto optimal set. The confirmation runs have been employed in order to make a decision about the optimal solution approved by experiment. Thus, the optimum conditions of nickel electroplating has been defined in this work as J* = 5.35 (A/dm²), T* = 33.44 (°C) and pH* = 6.22 and respectively the responses confirmed by experiment were Y = 79.12 ± 0.18 (%), U = 52.77 ± 0.48 (μm), V = 26.12 ± 0.45 (%) and W = 371.6 ± 1.77 (HV). In such conditions the quality of nickel electroplating deposit was the best one in accordance with experimental results.     

Optimum conditions for testing N-nitrosamine formation potential (FP) through ozonation in wastewater samples

N-nitrosamines are potential carcinogens that are formed during disinfection by chlorination/chloramination or ozonation. In this study, the main objective was to optimize ozonation experimental conditions (pH and temperature) for the production of N-nitrosamines by using the CCD method in wastewater matrices. As the results, maximum NDMA FP_O3 (formation potential by ozonation) occurred at pH 8.96 and a temperature of 20.0 °C. Furthermore, attempts to reduce the concentrations of eight N-nitrosamines revealed that none was removed or reduced in concentration by ozonation using Milli-Q water for 2 h.     

Preparation and optimization of matrix metalloproteinase-1-loaded poly(lactide-co-glycolide-co-caprolactone) nanoparticles with rotatable central composite design and response surface methodology

Matrix metalloproteases are key regulatory molecules in the breakdown of extracellular matrix and in inflammatory processes. Matrix metalloproteinase-1 (MMP-1) can significantly enhance muscle regeneration by promoting the formation of myofibers and degenerating the fibrous tissue. Herein, we prepared novel MMP-1-loaded poly(lactide-co-glycolide-co-caprolactone) (PLGA-PCL) nanoparticles (NPs) capable of sustained release of MMP-1. We established quadratic equations as mathematical models and employed rotatable central composite design and response surface methodology to optimize the preparation procedure of the NPs. Then, characterization of the optimized NPs with respect to particle size distribution, particle morphology, drug encapsulation efficiency, MMP-1 activity assay and in vitro release of MMP-1 from NPs was carried out. The results of mathematical modeling show that the optimal conditions for the preparation of MMP-1-loaded NPs were as follows: 7 min for the duration time of homogenization, 4.5 krpm for the agitation speed of homogenization and 0.4 for the volume ratio of organic solvent phase to external aqueous phase. The entrapment efficiency and the average particle size of the NPs were 38.75 ± 4.74% and 322.7 ± 18.1 nm, respectively. Further scanning electron microscopy image shows that the NPs have a smooth and spherical surface, with mean particle size around 300 nm. The MMP-1 activity assay and in vitro drug release profile of NPs indicated that the bioactivity of the enzyme can be reserved where the encapsulation allows prolonged release of MMP-1 over 60 days. Taken together, we reported here novel PLGA-PCL NPs for sustained release of MMP-1, which may provide an ideal MMP-1 delivery approach for tissue reconstruction therapy.     

Optimization of Osmo-convective Dehydration Process for the Development of Honey-ginger Candy Using Response Surface Methodology

Osmotic dehydration of ginger with honey is an interesting alternative for the development of confectionary-based functional food with extended shelf life. Response surface methodology (RSM) was used to investigate the effects of process variables on solid gain, water loss, and overall acceptability of honey-ginger candy. The process variables included blanching time (6–10 min), osmotic solution temperature (30–50°C), immersion time (90–150 min), and convective drying temperature (50–70°C). The honey to ginger ratio was 4:1 (w/w) during all the experiments. Ginger cubes were blanched before osmotic dehydration to increase the permeability of the outer cellular layer of tissue. After osmotic concentration of ginger with honey, convective dehydration was done to final moisture content of 3–5% (w.b.) to make it a shelf-stable product. Finally, osmo-convectively dried ginger was coated with sucrose for candy preparation. The optimum osmo-convective process conditions for maximum solid gain, water loss, and overall acceptability of honey-ginger candy were 7.07 min blanching time, 50°C solution temperature, 150 min immersion time, and 60°C convective drying temperature.     

Application of experimental design for removal of sunset yellow by copper sulfide nanoparticles loaded on activated carbon

In this study, copper sulfide nanoparticles loaded on activated carbon (CuS-NP-AC) was synthesized by novel, low cost and green approach and characterized using different techniques such as SEM, and BET. This material was used for the removal of sunset yellow (SY) from aqueous solutions was investigated. The dependency of removal percentages to variables such as pH, initial SY concentration, adsorbent dosage and sonication time were studied by central composite design (CCD) coupled with response surface methodology (RSM) by considering the desirability function (DF). The accuracy and ability of method at optimum values predicted by this model was studied by conduction of similar experiments at the same previously optimized conditions. A good agreement between experimental and predicted data was achieved that efficiency of this model for prediction of real optimum point. Among the well known previously isotherm models, the experimental equilibrium data efficiently can be represented by the Langmuir model, while the rate of adsorption. Kinetic data efficiently can be interpreted by combination of pseudo-second order as well as intraparticle diffusion models. The small amount of this adsorbent (0.016 g) is applicable for removal of high amount of SY (>90%) in reasonable time (17 min).     

Ionic liquid based periodic mesoporous organosilica: An efficient support for removal of sunset yellow from aqueous solutions under ultrasonic conditions

The efficiency of an ionic liquid based periodic mesoporous organosilica (PMO-IL) in the removal of sunset yellow from aqueous solutions using ultrasonic assisted adsorption method was investigated. The PMO-IL was first characterized by nitrogen sorption and TEM techniques. The optimized conditions (0.013 g of adsorbent, 32 mg L⁻¹ of sunset yellow at 2 min of sonication time and pH 7) were obtained by central composite design (CCD). Fitting the equilibrium data show the suitability of the Langmuir model with second-order equation to control the kinetic of the adsorption process and good reusability (5 cycles) of PMO-IL for adsorption of dye.     

Synergistic Effect of Pd/C and Novozyme 435 on the Dynamic Kinetic Resolution of 1,1,1-trifluoroisopropylamine

Response surface methodology (RSM) was successfully applied to study the synergistic effect of Pd/C and Novozyme 435 on the dynamic kinetic resolution of 1,1,1-trifluoroisopropylamine (TFPA). The variables taken into consideration were reaction temperature, substrate concentration, the Pd/C amount, and the Novozyme 435 amount. A statistical model was used to evaluate the influence of the variables on the conversion and enantiomeric excess (ee). It was found that the interaction between the Novozyme 435 and Pd/C was a significant parameter that affected TFPA conversion. The optimum conditions for RSM were: reaction temperature of 35°C, substrate (±) ? 1 concentration of 0.4 mol/L, 60 g/L of Novozyme 435, and 42.4 g/L of Pd/C (3 wt% of Pd on active carbon). The actual experimental conversion was 95.6% under optimum conditions, which was comparable to the maximum predicted value of 95.7%.     

Multifactorial Approach to Biosurfactant Production by Adaptive Strain Candida tropicalis MTCC 230 in the Presence of Hydrocarbons

In this study, Candida tropicalis MTCC 230 was used to adapted in hydrocarbon along with glucose for biosurfactant production, showing diauxic growth during the production. Biosurfactant was characterized through TLC and FTIR analysis as surfactin, a lipopeptide. Process parameters were optimized one factor at a time, showing the highest emulsification index (%E₂₄) at 54 %. The production of biosurfactant was enhanced by using biostatistically based experimental design with the interactive effect of different parameters. On the basis of Placket–Burman design, four factors, hydrocarbon, ammonium chloride, microelements and temperature are found to be significant (P < 0.05) for the production of biosurfactant. A second order polynomial regression model in central composite design estimated the maximum biosurfactant production in terms of the emulsification index (%E₂₄). The optimum combination of different parameters for the biosurfactant production, obtained for hydrocarbon, ammonium chloride, microelements and temperature are 81.41 %, 1.63 (g/l), 1.69 (g/l) and 35.25 °C, respectively. The biosurfactant production was increased twofold after optimization and selection of interactive parameters by response surface methodology.     

OPTIMIZATION OF PROCESS CONDITIONS USING RESPONSE SURFACE METHODOLOGY (RSM) FOR ETHANOL PRODUCTION FROM WASTE CASHEW APPLE JUICE BY ZYMOMONAS MOBILIS

Ethanol has been known for a long time, being perhaps the oldest product obtained through traditional biotechnology. It is an attractive, sustainable energy source for fuel additives. Based on a four-level central composite design (CCD) involving the variables substrate composition (20–100%) X₁, pH (4.5–6.5) X₂, incubation temperature (28°–36°C) X₃, and fermentation time (12–60 h) X₄, a response surface methodology (RSM) for the production of ethanol using waste cashew apple juice as substrate by Zymomonas mobilis MTCC 090 was standardized. The design contains a total of 31 experimental trials with the first 16 organized in a fractional factorial design and 25 to 31 involving the replications of the central points. Data obtained from RSM on ethanol production were subjected to the analysis of variance (ANOVA) and analyzed using a second-order polynomial equation, which resulted in the optimized process conditions of 62% (v/v) as substrate concentration, pH of 5.5, temperature of 32°C, and fermentation time of 37 h. Maximum ethanol concentration (12.64 g/L) was obtained at the optimized conditions in an anaerobic batch fermentation.     

Optimization of Mechanical Characteristics of Short Glass Fiber and Polytetrafluoroethylene Reinforced Polycarbonate Composites via D-Optimal Mixture Design

This paper deals with the application D-optimal mixture design (DMD) integrating response surface methodology (RSM) to discuss variation of mechanical characteristics depending on injection molding during production of short glass fiber (SGF) and polytetrafluoroethylene (PTFE) reinforced polycarbonate (PC) composites. Planning of experiments was based on a D-optimal mixture design (DMD). By applying RSM analysis, a mathematical predictive model of the tensile strength and flexural strength properties was developed in terms of the mixture ratio of PC, SGF, and PTFE. In addition, analysis of variance (ANOVA) and response surface graphs were applied to identify the effect of mixture ratio of SGF and PTFE reinforced PC composites for the tensile strength and flexural strength.     

Optimization and modeling of UV-TiO2 mediated photocatalytic degradation of golden yellow dye through response surface methodology

In this article, heterogeneous photocatalysis of golden yellow (GY) dye by Evonik p25 titanium dioxide (PTD) and UV radiations was optimized by using central composite design of response surface methodology. The GY dye photocatalysis was expressed as the function of amount of PTD loading (X₁), GY dye initial concentration (X₂), and UV irradiance intensity (X₃). The optimization of degradation conditions was done by measuring two different responses, that is, color removal (Y₁) and chemical oxygen demand removal (Y₂). The effect of X₁, X₂, and X₃ were studied in the range 0.5–1.5?g/L, 15–35?W/m², and 10–30?mg/L, respectively. The quadratic model was suggested for Y₁ and Y₂. The numerical optimization of results was done via Design Expert software. The predictive results obtained were verified by performing actual experiments. The photodegradation kinetics, total organic carbon disappearance, effect of inorganic salts, and H₂O₂ concentration on GY dye photodegradation were also studied.     

Modeling and optimization of process parameters for supercritical CO2 extraction of Argemone mexicana (L.) seed oil

This research article deals with the determination of optimal conditions of extraction parameters (e.g. temperature (60–100?°C), pressure (200–350?bar), particle size (0.5–1.0?mm), flow rate-CO₂ (5–15?g/min), and the % of co-solvent (0.0–10% of flow rate-CO₂) resulting to the optimal cumulative extraction yield during the supercritical fluid extraction of Argemone mexicana (L.) seed oil with and without a modifier (ethanol) using a supercritical carbon dioxide as solvent. A “five-factors-three-levels” Box-Behnken design under the response surface methodology was used to show independent and interactive effects of extraction parameters. A mathematical regression model was expressed properly by a quadratic second-order polynomial equation. The maximum oil yield (42.86%) from A. mexicana seeds was obtained with the optimal conditions (85?°C, 305?bar, 0.75?mm, 11?g/min, and 9% of flow rate-CO₂) of extraction parameters. The fatty acids analysis of the seed oil was done using gas chromatography and found its suitability as bio-fuel.     

Experiment research on mix design and early mechanical performance of alkali-activated slag using response surface methodology (RSM)

To enhance the quality of alkali-activated slag (AAS) materials, scientific and efficient mix design method is preferred. This paper presents an optimization of AAS materials using Response Surface Methodology (RSM). Three factors related to early strength such as modulus (n), concentration of alkali activator (CAA) and liquid–solid ratio (LSR) were investigated. Specimens with different mix ratios were prepared based on RSM design. The early mechanical performance was assessed, after 2 or 3 h of curing. Then response surface models were established and the effect law of each factor was systemically analyzed. The result shows that both n and CAA have a significant effect on the early strength, while LSR affects slightly. By adjusting the mix design parameters, the early performance of AAS can be effectively improved. This study verifies that RSM is efficient in the preparation of AAS and it can control the early strength of AAS accurately.