Biochips and microchemical systems utilize micromixers to mix various reactants in microscale environments effectively. The innovative microfluidic device is described. This study aims to enhance the Mixing Index (MI) by changing geometric parameters and inlet velocity. This micromixer consists of two unbalanced U-shaped channels connected by a chevron obstacle within a hexagonal mixing chamber, which promotes efficient fluid interaction. Numerical simulations are performed using the finite element-based COMSOL Multiphysics software, and the results are used to optimize the micromixer performance using response surface Methodology (RSM). It is found that the inlet velocity greatly affects the MI and pressure drop (Δp), whereas the angle between the inlets does not affect either of these parameters. For instance, MI increases from 80.85% to 94.52% when Uin is raised from 0.01 m/s to 1 m/s. In general, the suggested micromixer exhibits an MI higher than 80% for all ranges of the considered independent variables. Furthermore, two correlations for MI and Δp are provided by the RSM that can be used to maximize this micromixer's performance.

In this article, crashworthiness performance and crushing behavior of tapered structures with four internal reinforcing plates under axial and oblique dynamic loadings is investigated. These structures have a tapered form with five cross-sections of square, hexagonal, octagonal, decagon and circular shapes. In the first step, finite element simulations performed in LS-DYNA are validated by comparing with experimental data. The code generated in LS-DYNA is then used to investigate the energy absorption behavior of the tapered structures. response surface methodology and historical data design technique are employed to optimize the cross section perimeter (or tapered angle) of the tapered structures by considering two conflicting crashworthiness criteria including energy absorptionand peak crushing force. The optimization results show that the optimal tapered angle is enhanced by increasing the number of cross-section sides (or the number of corners). Then, the optimized tapered structures with different cross-sections are compared with each other using a ranking method called TOPSIS to introduce the most efficient energy absorber. The decagonal structure is finally found to be the best energy absorber.

response surface is an e ective method for robust parameter design. Previous response surface methodologies assume that independent variables are measured without errors. However, this assumption might be violated due to the low capability of the measurement system. The present study employs the response surface method for robust parameter design with measurement errors in variables. In addition, an unbiased estimator is presented in the presence of some measurement errors and an optimal setting which is determined to minimize the expected quadratic loss. An example is then illustrated to verify the e ectiveness of the proposed approach. The results showed that the proposed method could achieve better operating conditions, despite measurement errors, than the conventional method.

Background: Toxic heavy metals, such as lead, are widely used in industry and may cause serious health problems and ecological hazards for living organisms. Objectives: The current study aimed to investigate the removal efficiency of lead by Lactobacillus strains using a methodological approach. Methods: After selecting the bacteria with the maximum metals removal ability, experiments were conducted according to (i) the Plackett-Burman design (Minitab18 program) to screen several significant process factors and (ii) Central Composite design (design-Expert 11. 1. 2. 0 program) to find out the optimum process conditions for the maximum capacity of metal removal efficiency. Results: The optimum pH, metal, and bacterial concentration were 6. 76, 391 mg. L-1, and 4. 60 g. L-1 for lead removal ability of L. acidophilus ATCC4356. A quadratic model was developed to correlate the variables with removal efficiency. According to the results, this model was not statistically significant (P > 0. 05). Conclusions: The experimental removal efficiencies at the optimum condition for lead by L. acidophilus ATCC4356 (73. 9%) were consistent with the predicted values. Consequently, due to their appreciate efficiency and the lower cost of the lead removal ability, these two bacteria may be a candidate as good biosorbents. The results also confirmed that the response surface Methodology is an appropriate methodology for modeling of removal efficiency.

Inertial Particle Separator (IPS) is widely used as an important inlet protection device for turbo-shaft aero engine to protect the core engine in seriously polluted environment. In order to improve the separation efficiency of the IPS, an investigation was conducted to study the influence of critical geometrical and aerodynamic parameters on IPS performance, and response surface Method（ RSM） was applied to explore the interaction between different parameters and obtain the response of the IPS performance on different parameters. Results show the separation of the sand particle in the IPS is achieved by the inertial accumulation of the sand particle, the trajectories of particles with small size are dominated by flow direction while paths of particles with larger size are dominated by the individual particle inertia and bounce characteristics from the IPS walls. The separation efficiency of the IPS is not only affected by the single geometrical parameters or aerodynamic parameter, but also apparently influenced by the interaction effects between different parameters. The most conspicuous influencing factor for the IPS separation efficiency on the AC-Coarse dust is Math and the interaction effects between Ro1 and Math. IPS separation efficiency on the AC-Coarse dust is improved by 3. 8% by multi-factors optimization based on RSM, and the sand particle with size larger than 8 micron can be completely separated.

In this study, three-component nanoparticles of iron, nickel and lithium were synthesized with two methods of combined technique (co-precipitation, hydrothermal) and pechini sol-gel. The optimum conditions for producing MNPs by co-precipitation method were found to be at pH=13 with constant stirring rate of 1000 rpm and at temperature of 72 ˚ C under nitrogen atmosphere. The situation for preparing nanoparticles by pechini sol-gel method including dissolving nitrate salt of three metals in water then adding citric acid and ethylene glycol respectively in temperatures 60 and 80 0 C with pH=7 and placing sample in temperatures 190 and 500 0 C for 720 and 60 minutes respectively. In the comparison of two methods, morphology and size of produced magnetic nanoparticles with combined method of co-precipitation-hydrothermal was more suitable. response surface methodology was used to verify the best synthesized nanoparticles in size. Silica and amine groups in the coated nanoparticles were loaded to target drugs.

Missing observations occur in experimental designs as a result of insufficient sampling, machine breakdown, high cost, and errors in the measurements. In nanomanufacturing, missing observations often appear in designs because the combination of factors or molecular structures selected by a designer cannot be experimented successfully. In the current paper, Box-Behnken and face-centered composite designs were studied and eight robustness criteria including D-efficiency, tmax, tmax (1-a), and their related sub-criteria were considered to evaluate the robustness of the aforementioned designs. Finally, the integrated TOPSIS-AHP methodology was employed to select the most suitable robust design, and a numerical example was also presented to assess the applicability of the proposed approach.