scholarly journals Optimization of Synthesizing Upright ZnO Rod Arrays with Large Diameters through Response Surface Methodology

Processes ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 655
Author(s):  
Xiaofei Sheng ◽  
Yajuan Cheng ◽  
Yingming Yao ◽  
Zhe Zhao

The deposition parameters involved in chemical bath deposition were optimized by a response surface methodology to synthesize upright ZnO rod arrays with large diameters. The effects of the factors on the preferential orientation, aspect ratio, and diameter were determined systematically and efficiently. The results demonstrated that an increased concentration, elevated reaction temperature, prolonged reaction time, and reduced molar ratio of Zn2+ to tri-sodium citrate could increase the diameter and promote the preferential oriented growth along the [002] direction. With the optimized parameters, the ZnO rods were grown almost perfectly vertically with the texture coefficient of 99.62. In the meanwhile, the largest diameter could reach 1.77 μm. The obtained rods were merged together on this condition, and a dense ZnO thin film was formed.

2015 ◽  
Vol 4 (4) ◽  
Author(s):  
Seyed Mohammad Safieddin Ardebili ◽  
Teymor Tavakoli Hashjin ◽  
Barat Ghobadian ◽  
Gholamhasan Najafi ◽  
Stefano Mantegna ◽  
...  

AbstractThis work investigates the effect of simultaneous ultrasound-microwave irradiation on palm oil transesterification and uncovers optimal operating conditions. Response surface methodology (RSM) has been used to analyze the influence of reaction conditions, including methanol/palm oil molar ratio, catalyst concentration, reaction temperature and irradiation time on biodiesel yield. RSM analyses indicate 136 s and 129 s as the optimal sonication and microwave irradiation times, respectively. Optimized parameters for full conversion (97.53%) are 1.09% catalyst concentration and a 7:3.1 methanol/oil molar ratio at 58.4°C. Simultaneous ultrasound-microwave irradiation dramatically accelerates the palm oil transesterification reaction. Pure biodiesel was obtained after only 2.2 min while the conventional method requires about 1 h.


Author(s):  
Morteza Nazerian ◽  
Seyed Ali Razavi ◽  
Ali Partovinia ◽  
Elham Vatankhah ◽  
Zahra Razmpour

The main aim of this study is usability evaluation of different approaches, including response surface methodoloy, adaptive neuro-fuzzy inference system, and artificial neural network models to predict and evaluate the bonding strength of glued laminated timber (glulam) manufactured using walnut wood layers and a natural adhesive (oxidized starch adhesive), with respect to this fact that using the modified starch can decrease the formaldehyde emission. In this survey, four variables taken as the input data include the molar ratio of formaldehyde to urea (1.12–1.52), nanocellulose content (0%–4%, based on the dry weight of the adhesive), the mass ratio of the oxidized starch adhesive to the urea formaldehyde resin (30:70–70:30), and the press time (4–8 min). In order to find the best predictive performance of each selected evaluation approach, different membership functions were used. The optimal results were obtained when the molar ratio, nanocellulose content, mass ratio of the oxidised starch, and press time were set at 1.22, 3%, 70:30, and 7 min, respectively. Based on the performance criteria including root mean square error (RMSE) and mean absolute percentage error (MAPE) obtained from the modeling of response surface methodology, adaptive neuro-fuzzy inference network, and artificial neural network, it became evident that response surface methodology could offer a better prediction of the response with the lowest level of errors. Beside, artificial neural network and adaptive neuro-fuzzy inference system support the response surface methodology approach to evaluate bonding strength response with high precision as well as to determine the optimal point in fabrication of laminated products.


2019 ◽  
Vol 19 (4) ◽  
pp. 849
Author(s):  
Nurul Atikah Amin Yusof ◽  
Nursyamsyila Mat Hadzir ◽  
Siti Efliza Ashari ◽  
Nor Suhaila Mohamad Hanapi ◽  
Rossuriati Dol Hamid

Optimization of the lipase catalyzed enzymatic synthesis of betulinic acid amide in the presence of immobilized lipase, Novozym 435 from Candida antartica as a biocatalyst was studied. Response surface methodology (RSM) and 5-level-4-factor central-composite rotatable design (CCRD) were employed to evaluate the effects of the synthesis parameters, such as reaction time (20–36 h), reaction temperature (37–45 °C), substrate molar ratio of betulinic acid to butylamine (1:1–1:3), and enzyme amounts (80–120 mg) on the percentage yield of betulinic acid amide by direct amidation reaction. The optimum conditions for synthesis were: reaction time of 28 h 33 min, reaction temperature of 42.92 °C, substrate molar ratio of 1:2.21, and enzyme amount of 97.77 mg. The percentage yield of actual experimental values obtained 65.09% which compared well with the maximum predicted value of 67.23%. The obtained amide was characterized by GC, GCMS and 13C NMR. Betulinic acid amide (BAA) showed a better cytotoxicity compared to betulinic acid as the concentration inhibited 50% of the cell growth (IC50) against MDA-MB-231 cell line (IC50 < 30 µg/mL).


Author(s):  
Enmin Lv ◽  
Shaoxuan Ding ◽  
Jie Lu ◽  
Zhuang Li ◽  
Lixiong Du ◽  
...  

Abstract The integration process of polyethersulphone (PES) ultrafiltration with catalytic hydrolysis of lard was optimized by response surface methodology (RSM). The influences of molar ratio of water to lard, reaction time and transmembrane pressure on the fatty acids (FAs) yield were investigated. Results showed that the maximum FAs yield of 99.52 % was obtained under the optimized conditions of molar ratio of water to lard of 6.0:1.0, reaction time of 10.0 h and transmembrane pressure of 100.0 kPa. Moreover, the membrane cleaning efficiency was studied after four cleanings. Furthermore, the kinetic model of membrane separation process was investigated and the activation energy and pre-exponential factor were determined.


2015 ◽  
Vol 40 (3) ◽  
pp. 923-933 ◽  
Author(s):  
Mahtab Assadian ◽  
Mostafa Rezazadeh Shirdar ◽  
Mohd. Hasbullah Idris ◽  
S. Izman ◽  
Davoud Almasi ◽  
...  

2017 ◽  
Vol 2 (1) ◽  
pp. 1-10 ◽  
Author(s):  
O. S. Aliozo ◽  
L. N. Emembolu ◽  
O. D. Onukwuli

Abstract In this research work, melon oil was used as feedstock for methyl ester production. The research was aimed at optimizing the reaction conditions for methyl ester yield from the oil. Response surface methodology (RSM), based on a five level, four variable central composite designs (CCD)was used to optimize and statistically analyze the interaction effect of the process parameter during the biodiesel production processes. A total of 30 experiments were conducted to study the effect of methanol to oil molar ratio, catalyst weight, temperature and reaction time. The optimal yield of biodiesel from melon oil was found to be 94.9% under the following reaction conditions: catalyst weight - 0.8%, methanol to oil molar ratio - 6:1, temperature - 55°C and reaction time of 60mins. The quality of methyl ester produced at these conditions was within the American Society for Testing and Materials (ASTM D6751) specification.


2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Nichaonn Chumuang ◽  
Vittaya Punsuvon

The present study was performed to optimize a heterogeneous calcium methoxide (Ca(OCH3)2) catalyzed transesterification process assisted with tetrahydrofuran (THF) as a cosolvent for biodiesel production from waste cooking oil. Response surface methodology (RSM) with a 5-level-4-factor central composite design was applied to investigate the effect of experimental factors on the percentage of fatty acid methyl ester (FAME) conversion. A quadratic model with an analysis of variance obtained from the RSM is suggested for the prediction of FAME conversion and reveals that 99.43% of the observed variation is explained by the model. The optimum conditions obtained from the RSM were 2.83 wt% of catalyst concentration, 11.6 : 1 methanol-to-oil molar ratio, 100.14 min of reaction time, and 8.65% v/v of THF in methanol concentration. Under these conditions, the properties of the produced biodiesel satisfied the standard requirement. THF as cosolvent successfully decreased the catalyst concentration, methanol-to-oil molar ratio, and reaction time when compared with biodiesel production without cosolvent. The results are encouraging for the application of Ca(OCH3)2 assisted with THF as a cosolvent for environmentally friendly and sustainable biodiesel production.


2011 ◽  
Vol 233-235 ◽  
pp. 2739-2742
Author(s):  
C.G. Zhang ◽  
Zheng Fang Shi ◽  
J. Miao

There were carried on experiment in zinc sulfate and selenite sodium electrolyte solution. To further studying the influence of the ZnSe films ingredient and the appearance influence of electrochemical formation ZnSe thin films, the deposition parameters, which are the pH, Zn2+/SeO32- molar ratio, complexing agent sodium citrate, bath temperature and current density, are studied by the orthogonal experiment, the influence on Zn of the parameters from strong to weak are attained.


2015 ◽  
Vol 10 (2) ◽  
pp. 123-133 ◽  
Author(s):  
Mohammadreza Sabzimaleki ◽  
Barat Ghobadian ◽  
Mohsen Mazloom Farsibaf ◽  
Gholamhassan Najafi ◽  
Masoud Dehghani Soufi ◽  
...  

Abstract Production of biodiesel from castor oil (CO) using ultrasound-assisted has been investigated in this study. The objective of the present work was therefore to determine the relationship between various important parameters of the alkaline-catalyzed transesterification process to obtain a high reaction yield in a short time. The response surface methodology (RSM) was used to statistically analyze and optimize the operating parameters of the process. A central composite design (CCD) was approved to study the effects of the reaction time, the methanol to oil molar ratio, the ultrasonic cycle and the ultrasonic amplitude on reaction yield. The optimum conditions for alkaline-catalyzed transesterification of CO was found to be a reaction time of 540 s, methanol to oil molar ratio of 8.15:1,ultrasonic cycle of 0.73% and ultrasonic amplitude 64.34%. By exerting the calculated optimum condition in the process, the reaction yield reached 87.0494%. The results from the RSM analysis indicated that the reaction time has the most significant effect on the reaction yield.


2014 ◽  
Vol 20 (1) ◽  
pp. 127-134 ◽  
Author(s):  
Kumar Singh ◽  
Mausumi Mukhopadhyay

In the present work, solvent free olive oil glycerolysis for the monoglycerides (MG) and diglycerides (DG) production with an immobilized Candida rugosa lipase was studied. MG and DG production were optimized using experiment design techniques and response surface methodology (RSM). RSM based on five-level, a five-variable central composite design (CCD) was used to optimize MG and DG production: reaction time, temperature, molar ratio of glycerol to oil, amount of lipase, and water content in glycerol. The reaction time, temperature, and amount of lipase were observed to be the most significant factors on the process response. The immobilized Candida rugosa lipase revealed optimum yield of MG and DG as 38.71 and 40.45 wt% respectively following a 5h reaction time with 0.025 g of lipase and 5% water content in glycerol at 40?C temperature. The yield of MG and DG production can be enhanced 1.5 fold by RSM.


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