Optimization Of Different Factors Research Articles

Effect of different devulcanization agents on the mechano-chemical devulcanization process of waste tires

Herein, the effects of two devulcanization agents, i.e., disulfide oil (DSO) and tetramethyl thiuram disulfide (TMTD), byproducts of gas refineries, on the mechano-chemical devulcanization process of waste tires were investigated. The response surface methodology (RSM) involving Box-Behnken Design (BBD) was utilized for the optimization of different factors, i.e., reaction temperature, reaction time, and the content of devulcanization aids. Samples were prepared in a Brabender mixer at a temperature of 100°C, and a rotor speed of 80 RPM for 15 min, and the devulcanization percentage of the samples was determined using swelling test, Mooney viscosity, and Horikx’s theory. The results demonstrated that when 5 phr devulcanization agents were used, the devulcanization percentages for samples containing DSO and TMTD were 73 and 80%, respectively. In addition, the effect of reaction temperature, reaction time, and the content of devulcanization agents on the crosslink scission was also investigated. It was found that by increasing these three parameters, the crosslink density decreased while the devulcanization percentage increased. All in all, the results indicated that the performance of TMTD as devulcanization agent was better than that of DSO. We believe that our presented research study will open new avenues for effective recycling of waste rubbers.

Green synthesis of chitosan nanoparticles, optimization, characterization and antibacterial efficacy against multi drug resistant biofilm-forming Acinetobacterbaumannii

Chitosan nanoparticles (CNPs) are promising versatile cationic polymeric nanoparticles, which have received growing interest over last few decades. The biocompatibility, biodegradability, environmental safety and non-toxicity of the chitosan nanoparticles makes it preferred for a wide range of biological applications including agriculture, medical and pharmaceutical fields. In this study, CNPs were biosynthesized by aqueous extract of Eucalyptusglobulus Labill fresh leaves as bio-reductant. Box–Behnken design in 29 experimental runs was used for optimization of different factors affecting the production of CNPs. The maximum yield of CNPs was 9.91 mg/mL at pH of 4.5, chitosan concentration of 1%, incubation time of 60 min and temperature of 50 °C. The crystallinity, particle size and morphology of the biosynthesized CNPs were characterized. The CNPs possess a positively charged surface of 31.1 mV. The SEM images of the CNPs confirms the formation of spherical form with smooth surface. The TEM images show CNPs were spherical in shape and their size range was between 6.92 and 10.10 nm. X-ray diffraction indicates the high degree of CNPs crystallinity. FTIR analysis revealed various functional groups of organic compounds including NH, NH2, C–H, C−O, C–N, O–H, C–C, C–OH and C–O–C. The thermogravimetric analysis results revealed that CNPs are thermally stable. The antibacterial activity of CNPs was determined against pathogenic multidrug-resistant bacteria, Acinetobacterbaumannii. The diameters of the inhibition zones were 12, 16 and 30 mm using the concentrations of 12.5, 25 and 50 mg/mL; respectively. When compared to previous studies, the biosynthesized CNPs produced using an aqueous extract of fresh Eucalyptusglobulus Labill leaves have the smallest particle sizes (with a size range between 6.92 and 10.10 nm). Consequently, it is a promising candidate for a diverse range of medical applications and pharmaceutical industries.

Application of Molecularly Imprinted Poly-Itaconic/Multiwalled Carbon Nanotubes for Selective and Sensitive Electrochemical Detection of Linagliptin

In this work, we report the first molecularly imprinted polymer (MIP) based electrochemical sensor for the determination of the antidiabetic drug Linagliptin (LNG) in pure sample, tablets, and spiked human urine and serum samples. Using a graphite electrode, differential pulse voltammetry (DPV) was applied to study the electrochemical behavior of LNG in a Britton Robinson (BR) universal buffer of pH 8 with Ag/AgCl electrode and Pt wire. The sensor is based on the modification of the traditional carbon paste sensor with Itaconic acid (IA) as monomer, which cross-linked using ethylene glycol dimethacrylate (EGDMA) and multiwalled carbon nanotubes (MWCNTs) as a modifier. The different factors were optimized, such as ratio of MIP components, percentage of multiwalled carbon nanotubes (MWCNT), pH, accumulation time, accumulation potential and scan rate. The proposed sensor was characterized morphologically using: Scanning electron Microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR) and Brunauer–Emmett–Teller (BET) and electrochemically applying electrochemical impedance spectroscopy (EIS)and cyclic voltammetry (CV). DPV was applied to obtain the calibration curve and optimization of different factors, the proposed sensor shows a wide linear range of 1 × 10−12M (0.47 ng l−1) to 1 × 10−7M (47.26 μg l−1) and limit of detection (LOD)1 × 10−13M (0.05 ng l−1) while the limit of quantification (LOQ)was found to be 3.3 × 10−13M (0.16 ng l−1) in addition to good reproducibility and selectivity.

Optimization of Different Factors for Initiation of Somatic Embryogenesis in Suspension Cultures in Sandalwood (Santalum album L.)

Santalum album (L.) is a prized tropical tree species of high therapeutic and industrial importance. The wood of these naturally grown plants is extensively harvested to acquire therapeutically important metabolite santalol and be used for additional functions such as in wood statuette industries. Due to high demand, it is crucial to maintain a sufficient plant population. An easy protocol for establishing cell suspension culture initiated from the loose embryogenic callus mass of sandalwood was realized by shifting 6–8-week-old morphogenic calli acquired from the mature embryonic axis and cotyledon explant cultures in fluid media. The asynchronous embryogenic cultures were sloughed with clumps of flourishing cell clumps and embryos of various progressive phases along with diffident non-embryogenic tissues. The frequency of embryo proliferation was evidenced to determinethe expansion pace of embryogenic masses under diverse conditions. The intonation of initiation and creation of cell suspension was under the directive of the influence of exogenous plant growth regulators amended in the nutrient medium at different concentrations and combinations. Maximum relative growth rate (386%) and clumps/embryoids in elevated integers (321.44) were accomplished on MS nutrient medium fortified with 2.0 mg L−1 2,4-D in association with 0.5 mg L−1 BA and 30.0 g L−1 sucrose raised from mature embryonic axis-derived calli. Plantlet regeneration in higher frequency (84.43%) was evidenced on MS medium amended with 1.0 mg L−1 each of TDZ and GA3 in conjunction with 0.5 mg L−1 NAA and 20.0 g L−1 sucrose. Mature embryonic axis-derived calli were found to be constantly better than mature cotyledon-derived calli for raising profitable and reproducible cell suspension cultures. Regenerants displayed normal growth and morphology and were founded successfully in the external environment after hardening.

Graphene quantum dots based on maltose as a high yield photocatalyst for efficient photodegradation of imipramine in wastewater samples.

In this work, for the first time, graphene quantum dots (GQDs) based on maltose were fabricated as a new photocatalytic material to the photodegradation of imipramine (as a persistence organic pollutant) under light irradiation. The synthesized GQDs were characterized by different instrumentation approaches such as X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), nitrogen adsorption/desorption, and transmission electron microscopy (TEM). A Box-Behnken design (BBD) and the response surface methodology (RSM) were applied for the optimization of different factors that affect the overall photocatalytic yield. Under the optimized conditions (pH of the sample solution: 2.0; photocatalyst dosage: 0.1mgmL-1; UV exposure time: 80min), the highest achievable reduction efficiency was obtained about 80%. The stability and reusability of the synthesized photocatalytic material were investigated in four reaction cycles (80min), which showed only a 15% photo-activity loss after the fourth photocatalytic runs. The proposed method was successfully applied to degrade the mentioned drug in the real wastewater samples by about 70%. Regarding the mentioned advantages by the proposed method, this new kind of photocatalytic material possesses a strong potential for photodegradation of pollutants in industrial wastewater samples. Photodegradation of imipramine using graphene quantum dots based on maltose.

Establishing the Order of Importance Factor Based on Optimization of Conditions in PAHs Biodegradation

In environmental study, optimization of different factors is crucial to obtain high removal of specific pollutants. The sequence of important factors that were considered in optimization studies is less concerned, and this part is crucial before proceeding to full-scale bioremediation study. This study focuses on bioremediation of polycyclic aromatic hydrocarbons (PAHs) contaminated soil with the potential bacteria, Corynebacterium urealyticum which is isolated from municipal sludge. The bacterial strain has evaluated the effectiveness of PAHs degradation at various factors on soil pH, soil temperature, initial PAHs concentration, initial bacteria number, and heavy metals concentration. The optimum condition for phenanthrene biodegradation was pH 7, 30 °C, 500 mg/kg of phenanthrene concentration, 109 cells/g soil, and without the addition of Zn. In establishing the ranking, we attempt to use a simple method based on the analysis of p values. Based on the analysis of degradation rates, the initial phenanthrene concentration shows the lowest p value, which means that it shows the highest ranking; the most significant factor to achieve highest degradation. In vice versa, the soil pH shows the highest ranking based on the analysis of bacteria growth rates, which is a very limited study that focuses on growth rates in the optimization study. The establishment of these rankings may reduce time, energy and cost in pilot or field study and at the same time achieve highest degradation in bioremediation work. Thus, it is highly recommended to develop the ranking before proceeding to design work in pilot and field study.

Optimization of process variables for enhanced production of urease by indigenous Aspergillus niger strains through response surface methodology

Abstract Urease is one of the important enzymes secreted by microorganisms in the soil, but can also be produced by microbial fermentation. The present study aimed to explore optimum conditions for maximum urease enzyme production from wheat straw by applying a statistical approach, response surface methodology (RSM), under the solid-state fermentation process. Eight different local strains of Aspergillus niger were screened for the production of urease enzyme. Fermentation profile revealed that all the strains showed activity but two strains BMB-02 NSJ and BMB-05 G displayed the higher activity as compared to the other strains. Therefore, two strains explicitly BMB-02 NSJ and BMB-05 G were shortlisted for further optimization studies. Different process parameters including incubation time, temperature, and pH were optimized for urease production. The result showed that both strains of A. niger (BMB0-02 NSJ and BMB-05 G) displayed maximum enzyme activity at 144 h (6 days), 35 °C, and pH 9.0, respectively. Moreover, RSM was employed to optimize the different parameters such as biomass, inoculum size, nitrogen content and moisture for both strains. Optimal enzyme conditions for BMB-02 NSJ were biomass, inoculum size, nitrogen, and moisture of 10 g, 5 mL, 0.5 g and 250% ratio to biomass, respectively, whereas biomass, inoculum size, nitrogen and moisture content of 6 g, 3 mL, 150% ratio to biomass without the addition of any nitrogen were found for BMB-05 G. The findings revealed that optimization of different factors have a significant effect on urease production, and RSM-based optimization is a promising and time-saving technique.

Synergistic Effect of the Electronic Structure and Defect Formation Enhances Photocatalytic Efficiency of Gallium Tin Oxide Nanocrystals

The design of photocatalysts with enhanced efficiency is pivotal to sustainable environmental remediation and renewable energy technologies. Simultaneous optimization of different factors affecting the performance of a photocatalyst, including the density of active surface sites, charge carrier separation, and valence and conduction band redox potentials, remains challenging. Here, we report the synthesis of ternary gallium tin oxide (GTO) nanocrystals (NCs) with variable composition and investigate the role of Ga3+ dopants in altering the electronic structure of rutile-type SnO2 NC lattice using steady-state and time-resolved photoluminescence spectroscopies. Substitutional incorporation of Ga3+ increases the band gap of SnO2 NCs, imparting the reducing power to the conduction band electrons, and causes the formation of acceptor states, which, in conjunction with electron trapping by donors (oxygen vacancies), leads to stabilization of the photoexcited carriers. Combination of a decrease in the charge re...

Smart Home System for Energy Saving using Genetic- Fuzzy-Neural Networks Approach

Home energy saving is very important to realize sustainable improvement. This can be achieved by designing a smart home system that provides a productive and cost-effective environment through optimization of different factors that will be explained in this paper. In this paper, an adaptive smart home system for optimal utilization of power will be designed. The system is based on genetic-fuzzy-neural networks technique, which can capture a human behavior patterns and use it to predict the user's mood. This technique will improve the intelligence of the smart home control to minimize the power losses.

Preparation of a New Solid‐Phase Microextraction Fiber by Coating Silylated Nanoporous Silica on a Copper Wire

AbstractLUS‐1 typed nanoporous silica particles were synthesized and silylated with hexamethyldisilazane and investigated as a highly porous fiber coating for solid‐phase microextraction (SPME). The pore size distribution of the prepared Sil‐LUS‐1 was still typical of MCM‐41 and centered at 3 nm with a specific surface area of 720 m2g−1. The SPME fiber was prepared by liming the material on a copper wire. The extraction efficiency of the new fiber was compared with a commercial PDMS fiber for headspace extraction and GC‐MS analysis of phenol, 4‐nitrophenol, 2,4‐dichlorophenol and 4‐chlorophenol in water samples. Due to the high porosity of the prepared fiber it showed a higher sensitivity and better selectivity for the extraction of the target compounds. For optimization of different factors affecting the extraction efficiency, a simplex optimization method was used. The relative standard deviation for the measurements by one fiber was better than 7% for five replicates and the fiber‐to‐fiber reproducibility was about 10% for five fabricated fibers. Detection limits in the range of 0.002 to 0.026 μg mL−1 were obtained for the phenolic compounds. The fiber was successfully applied for the determination of phenolic compounds in natural water samples.

Isolation of biosurfactant-producing Pseudomonas aeruginosa RS29 from oil-contaminated soil and evaluation of different nitrogen sources in biosurfactant production

An efficient biosurfactant-producing native Pseudomonas aeruginosa RS29 has been isolated from crude oil contaminated soil. Isolation was followed by optimization of different factors to achieve maximum production of biosurfactant in terms of surface tension reduction (STR) and emulsification index (E24). The isolated strain produced highest biosurfactant in the presence of glycerol after 48 h of incubation at 37.5°C, with pH range of 7–8 and at salinity <0.8% (w/v). The extent of STR and the E24 of medium with different nitrogen sources were investigated and found to be maximal for sodium nitrate (26.3 mN/m, E24 = 80%) and potassium nitrate (26.4 mN/m, E24 = 79%). The production of biomass by the designated strain was found to be maximal in ammonium-nitrate-containing medium as compared to the other nitrogen sources. A kinetic study revealed that biosurfactant production is positively correlated with growth of P. aeruginosa, and highest STR was achieved (27.0 mN/m) after 44 h of growth. The biosurfactant was produced as a primary metabolite and 6 g/L crude biosurfactant was extracted by chloroform:methanol (2:1). The critical micelle concentration of the biosurfactant was 90 mg/L. The absorption bands of the FTIR spectra confirmed the rhamnolipid nature of the biosurfactant. The biosurfactant was thermostable (up to 121°C for 15 min) and could withstand a wide range of pH (2–10) and NaCl concentration (2%–10% w/v). The extracted biosurfactant had good foaming and emulsifying activities and was of satisfactory quality in terms of stability (temperature, pH and salinity) and foaming activity.

Optimization of different factors for efficient protoplast release from entomopathogenic fungusMetarhizium anisopliae

Optimization of different factors for efficient protoplast release fromMetarhizium anisopliae was investigated. Factors like culture media, age of the mycelium, incubation time, different enzymatic combinations and osmotic stabilizer were studied. Mycelium harvested at 40th h in Sabouraud Dextrose broth showed the best protoplast yield over the other media and age of mycelium tested. An incubation time of 3 h and Lysing enzyme at a concentration of 10 mg/ml was the best among the different enzymatic concentrations and combinations tested and yielded a protoplast release of 7.3×108 protoplasts/ml. The most suitable osmotic stabilizer for efficient protoplast release was 0.7M KCl.