Response Surface Technique Research Articles

Adsorption and removal of Pb (II) via layer double hydroxide encapsulated with chitosan; synthesis, characterization adsorption isotherms, kinetics, thermodynamics, & optimization via Box-Behnken design

The study aimed to enhance the stability and efficiency of removing bivalent Pb(II) by encapsulating AlNi-layered double hydroxide (LDH) in chitosan and itaconic acid to create an adsorbent with chemically active sites. The resulting material, AlNi-LDH/CS, underwent thorough property analysis using XRD, FT-IR, XPS, EDX, N2 adsorption/desorption isotherm, and FESEM to find out what textural characteristics it has. Specifically, nitrogen adsorption/desorption isotherms were utilized to assess the textural properties of AlNi-LDH/CS. The Al/Ni-LDH/CS surface displayed a specific surface area of 71.95 m2/g and an average pore size of 2.537 nm, consistent with the platelets' external surface. The effects of dose, pH, temperature, and starting concentration on the adsorption process were also investigated in this study. The adsorption characteristics have been examined by means of equilibrium and adsorption kinetics. The adsorption process adhered to the pseudo-second-order and Langmuir isotherm models. The predominant adsorption process was found to be chemisorption, which had an adsorption energy of 28.42 kJ·mol−1. An endothermic and spontaneous adsorption process is suggested by the increase in metal absorption at increasing temperatures. The Box-Behnken design software was utilized to establish the optimal adsorption parameters as pH 5, a dosage of 0.2 g of AlNi-LDH/CS per 25 mL, and an adsorption capacity of 453.05 mg/g for the Pb(II) arsenate solution. For the composite sponge to be most effective in adsorbing arsenate and be used in water purification procedures, these factors are essential. The adsorption process was successfully improved with few planned tests by applying the Box-Behnken design and response surface technique aspects of the Design-Expert software. An evaluation of the adsorbent's reusability using six successive cycles of adsorption and desorption confirmed its stability and showed no discernible decrease in removal efficiency. Additionally, it retained its original chemical composition before and after reuse, showcased consistent efficiency, and maintained uniform XRD data.

Evaluating the mechanical and environmental impact of PEF plastic waste incorporated with graphene nano-platelets in concrete

There has been a significant surge in the yearly use of plastics, leading to a notable rise in plastic waste generation. Consequently, the recycling of plastic garbage has emerged as a prominent concern around the world. This research explores the feasibility of using polyethylene furanoate (PEF) plastic waste as a substitute for coarse aggregate (CA) in concrete. Graphene nano-platelets (GNPs) were added to the concrete mix in different quantities to improve its structural reliability. The research study used an experimental research design in conducting its investigation. PEF waste plastic was added in concrete in varying proportions of 0%, 5%, 15%, 20%, and 25% as a supplementary material to gravel, and GNPs were added in different percentages of 0%, 0.03%, 0.05%, 0.08%, and 0.1% by weight of cement. Mechanical tests were conducted, which includes compressive strength (CS), split tensile strength (STS), flexural strength (FS), modulus of elasticity (MoE), and ultrasonic pulse velocity (UPV), and the environmental assessment of concrete was done by assessing carbon in concrete and concrete’s eco efficiency (ESE). It was found that 5% addition of PEF as the substitute to CA and 0.1% of GNPs gives the optimum strength, enhancing CS, STS, and FS by 9.10%, 18.18%, and 4.45%, respectively. Response surface technique (RSM) models were created to provide mathematical equations for predicting the predicted outcomes. All models were optimized using a multi-objective optimization approach and then validated.

Investigation of the hydraulic performance heat improvement in 3D pipe by variable of novel twisted tape configurations based on CFD and DoE analysis methods

Enhancing heat transfer is a key area that is closely related to economically efficient systems in various forms of energy saving. The insert of twisted are regarded as thermal method. Goal of the current study was to thoroughly assess how using several approaches at the same time affected the tube heat exchanger’s thermal flow, and thermal enhancement. Different twisted configurations were used such as twisted width, thickness of twisted, turn numbers, and thickness of inward are the modified geometrical parameters. Design of the experiments approach is used to investigate how different geometrical parameters affect the improvement of heat and hydraulic thermofluid pattern in twisted tube heat exchangers as the output variables. The Response Surface technique was also used to investigate and identify various outcome models. Taguchi analysis was applied to optimize the experimental design by investigating changes and executing orthogonal arrays. Additionally, the experimental study design was the orthogonal array L16. The performance parameter was optimized separately, and then the DoE methodology was combined with Taguchi method (TM) and response surface methodology (RMS) to optimize all parameters. In this work, the ideal twisted tape design is discovered through the application of CFD numerical approach in conjunction with RSM and TM. Compared results to traditional pipe, improvement in heat is roughly 42.81 % and 42.72 % for temperature differentials and heat transfer rate performance, respectively.

Environmental risk evaluation for radionuclide transport through natural barriers of nuclear waste disposal with multi-scale streamline approaches

Natural barriers, encompassing stable geological formations that serve as the final bastion against radionuclide transport, are paramount in mitigating the long-term contamination risks associated with the nuclear waste disposal. Therefore, it is important to simulate and predict the processes and spatial-temporal distributions of radionuclide transport within these barriers. However, accurately predicting radionuclide transport on the field scale is challenging due to uncertainties associated with parameter scaling. This study develops an integrated evaluation framework that combines upscaled parameters, streamline transport models, and response surface techniques to systematically assess environmental risk metrics and parameter uncertainties across different scales. Initially, upscaling methods are established to estimate the prior interval of critical transport parameters at the field scale, and streamline models are derived by considering the radionuclides transport with a variety of physicochemical mechanisms and geological characterizations in natural barriers. To assess uncertainty ranges of the risk metrics related to upscaled parameters, uncertainty quantification is performed on the ground of 5000 Monte Carlo simulations. The results indicate that the upscaled dispersivity of fractured media (αLf) has a relatively high sensitivity ranking on release dose for all nuclides, and upscaled matrix sorption coefficient (Kd) of Pu-242 strongly affects breakthrough time and release dose of Pu-242. Facilitated by robust response surface with the lowest R2 of 0.89, it is shown that the release doses of Pu-242 and Pb-210 increase under conditions of low Kd and αLf, respectively. Furthermore, statistical analysis reveals that employing limited laboratory-scale parameters results in narrower confidence intervals for risk metrics, while upscaling methods better account for the highly heterogeneous properties of large-scale field conditions. The developed risk evaluation framework provides valuable insights for utilizing upscaled parameters and modeling radionuclide transport within natural barriers under various scenarios.

Preparation and evaluation of microencapsulated delivery system of recombinant interferon alpha protein from rainbow trout

Diseases caused by viruses pose a significant risk to the health of aquatic animals, for which there are presently no efficacious remedies. Interferon (IFN) serving as an antiviral agent, is frequently employed in clinical settings. Due to the unique living conditions of aquatic animals, traditional injection of interferon is cumbersome, time-consuming and labor-intensive. This study aimed to prepare IFN microcapsules through emulsion technique by using resistant starch (RS) and carboxymethyl chitosan (CMCS). Optimization was achieved using the Box-Behnken design (BBD) response surface technique, followed by the creation of microcapsules through emulsification. With RS at a concentration of 1.27 %, a water‑oxygen ratio of 3.3:7.4, CaCl2 at 13.67 %, CMCS at 1.04 %, the rate of encapsulation can escalate to 80.92 %. Rainbow trout infected with Infectious hematopoietic necrosis virus (IHNV) and common carp infected with Spring vireemia (SVCV) exhibited a relative survival rate (RPS) of 65 % and 60 % after treated with IFN microcapsules, respectively. Moreover, the microcapsules effectively reduced the serum AST levels and enhanced the expression of IFNα, IRF3, ISG15, MX1, PKR and Viperin in IHNV-infected rainbow trout and SVCV-infected carp. In conclusion, this integrated IFN microcapsule showed potential as an antiviral agent for treatment of viral diseases in aquaculture.

Novel Response Surface Technique for Composite Structure Localization Using Variable Acoustic Emission Velocity.

The time difference of arrival (TDOA) method has traditionally proven effective for locating acoustic emission (AE) sources and detecting structural defects. Nevertheless, its applicability is constrained when applied to anisotropic materials, particularly in the context of fiber-reinforced composite structures. In response, this paper introduces a novel COmposite LOcalization using Response Surface (COLORS) algorithm based on a two-step approach for precise AE source localization suitable for laminated composite structures. Leveraging a response surface developed from critical parameters, including AE velocity profiles, attenuation rates, distances, and orientations, the proposed method offers precise AE source predictions. The incorporation of updated velocity data into the algorithm yields superior localization accuracy compared to the conventional TDOA approach relying on the theoretical AE propagation velocity. The mean absolute error (MAE) for COLORS and TDOA were found to be 6.97 mm and 8.69 mm, respectively. Similarly, the root mean square error (RMSE) for COLORS and TODA methods were found to be 9.24 mm and 12.06 mm, respectively, indicating better performance of the COLORS algorithm in the context of source location accuracy. The finding underscores the significance of AE signal attenuation in minimizing AE wave velocity discrepancies and enhancing AE localization precision. The outcome of this investigation represents a substantial advancement in AE localization within laminated composite structures, holding potential implications for improved damage detection and structural health monitoring of composite structures.

Parameters design optimization of grading ring based on electric field analysis through response surface methodology

This research delves into the primary cause of the ageing of insulated cross-arms in the field, which is attributed to the high electric stress experienced at the end fittings. To address this issue, a novel technique is introduced to meticulously analyse the influence of Grading rings on the electric field (E-field) stress, with the goal of regulating it within the prescribed limits on the surface of the insulated cross-arm. By employing advanced methodologies such as finite element analysis and design of experiment approaches, the impact of various geometrical characteristics of Grading rings on the E-field is comprehensively investigated. Through the application of the analysis of variance, the primary and interaction effects of these factors are carefully examined. Additionally, leveraging the power of the response surface technique, an optimal link between the E-field and the geometrical parameters is modelled and optimized. The results of this comprehensive study unequivocally reveal the profound influence of the geometrical parameters of Grading rings on the E-field. Furthermore, diligent efforts are made to estimate the Grading ring parameters that will effectively regulate the E-field within the suggested maximum threshold based on the derived model. The proposed technique not only significantly reduces the computational analysis time but also serves as an efficient and invaluable tool for investigating the intricate geometry of Grading rings without imposing any additional computing burden.According to the findings, the E-field is most impacted by the factors H, D, and T to optimise the shape of grading rings used in insulated cross-arms. The main objective was achieved by reducing the maximum E-field value by 65% compared to the E-field without a grading ring, which has been accomplished. The suggested technique provides a quick and easy way to analyse and improve the intricate geometry of grading rings. As a result, it lowers the cost and time related to computational analysis without needing an excessive amount of computing work to do this.

Metal-Organic Framework-Derived Solid Catalyst for Biodiesel Production from Jatropha curcas Oil: Kinetic Study and Process Optimization Using Response Surface Methodology

Jatropha curcas oil (JCO) is a promising source for the manufacturing of biodiesel and has gained a lot of attention due to its environmental friendliness and availability in many parts of the world as a result of the rising need for energy. In this study, JCO was converted to biodiesel using a heterogeneous CaO-ZrO2 catalyst made from biomass and MOFs. The central composite design of response surface technique was used to change the transesterification parameters to enhance JCO conversion. After optimization using RSM, the reaction parameters were set to a catalyst loading of 6.34 wt%, a reaction time of 68 minutes, a temperature of 92.9°C, and a methanol-to-oil molar ratio of 18 : 1; then, the yield of biodiesel was found to be 97.12±0.4%. Using various analytical techniques, the chemical composition, texture, and its morphology have been examined by FT-IR, SEM-EDS, XRD, TGA, and BET. Moreover, 1H NMR, 13C NMR, and GC-MS have all been used to describe the biodiesel that has been created. While the catalyst’s activity reduced, it was found that, after being washed with hexane and dried by calcination, it could still be used up to the fifth cycle.

Application of response surface methodology and neural networks in pyramid solar still for seawater desalination: An optimization and prediction strategy

<p>Potable water is essential in various aspects of daily life. Converting brackish water to drinkable water using traditional methods is costly and has environmental impacts. Solar energy is preferred over fossil fuels and other energy sources due to its cost and environmental benefits. Solar stills are increasingly popular due to the growing need for drinkable water, but their performance requires improvement. The study examines the pyramid solar still (PSS) productivity using different operating parameters, such as solar intensity (350-950 W/m2), water inlet temperature (30-50°C), water depth (4-8 cm), and insulation thickness (0.05-0.15m). The response surface technique (RSM) was used to examine the performance of the still under different operating conditions. The RSM approach optimized the process for maximum output and reduced testing time and effort. To verify the optimum response derived from RSM, the artificial neural networks (ANN) model was implemented. The comparative studies of the ANN and RSM models demonstrates a strong correlation with the outcomes achieved in maximizing the productivity of PSS. It found that the ideal values for solar intensity, water intake temperature, water depth, and insulation thickness are 950 W/m2, 50°C, 4 cm, and 0.15 m, respectively. These parameters contribute to the production of 2.585 kg/m2 of distillate.</p>

Treatment of wet coffee processing wastewater using a pulsed-electrocoagulation process: optimization using response surface technique

In this study, the removal efficiency of chemical oxygen demand (COD), color, turbidity, phosphate, and nitrate from wet coffee processing wastewater by pulsed-electrocoagulation process (PECP) was examined with various factors such as pH: 3–11, reaction time: 15–75 min, current: 0.150–0.750 Amp, and electrolyte concentration: 0.25–1.25 g/L. Several operational parameters for the treatment of wet coffee processing wastewater utilizing the PECP have been optimized through the application of the surface response design technique, which is based on the central composite design. A quadratic model helped estimate the percentage removal of COD, color, turbidity, phosphate, and nitrate with power consumption under various situations. It also evaluated the significance and their interaction with independent variables using analysis of variance (ANOVA). Through the use of statistical and mathematical techniques, optimum conditions were determined in order to remove the maximum pollutant and nutrient while using the minimum of power. The results showed that the removal of COD—98.50%, color—99.50%, turbidity—99.00%, phosphate—99%, and nitrate—98.83%, with a power consumption of 0.971 kWh m−3 were achieved at pH-7, NaCl dose of 0.75 g/L, electrolysis duration of 45 min, and current of 0.45 Amp. Therefore, under the different operating conditions, the PECP demonstrated to be a successful technique for pollutant removal from wastewater and industrial effluent.

Dry sliding wear characteristics of Al7075 alloy‐reinforced with SiC and cenosphere particles

AbstractAluminum metal matrix composite (AMMC) is employed in all engineering applications, most notably as a substitute for conventional metals in the fields of defense, automotive, and aerospace. AMMC should have a wide variety of structural, mechanical, thermal, wear, and corrosion qualities that may require mutually exclusive features at an optimal level to achieve this. The current research focuses on the stir casting process for producing SiC and cenosphere reinforced Al7075 alloys. The response surface method's (RSM) face‐centered central composite design (CCD) was used to design the number of experimental trials, and a response surface technique was enforced to forecast the optimum combination of processing variables in the wear process. The SiC reinforcement improved the wear resistance of Al7075‐SiC‐cenosphere composites substantially. Overall, the experiments show that Al7075‐6 wt% SiC‐5 wt% cenosphere has excellent tribological properties. The hybrid Al7075/SiC/Cenosphere composites were shown to be effective, fit, and suitable in the ideal wear process parameters (load of 10 N, sliding distance of 1000 m, and sliding velocity of 1.5 m/s) for lowering wear rate (0.38035 × 10−3 mm3/m) at 6wt% SiC reinforced composite. This suggests that the combination of SiC and cenosphere improves the wear resistance of AMMC.

Optimization and evaluation of the distribution of Fischer-Tropsch products over a cobalt-based catalyst utilising design expert software

Modelling biomass to liquid via the Fischer-Tropsch synthesis (FTS) system allows researchers to investigate the most efficient parameters while running the system under optimal conditions. As part of the design of experiments (DOE) procedure, a special data simulation method based on response surface methodology (RSM) is utilized to thoroughly analyse the impact of operating circumstances. The objective of this study was to examine the factors that affect the production of C1, C2–C4, and C5+ in FTS process, and then optimize the critical factors utilising factorial design and response surface techniques. The parameters evaluated were reaction temperature, reaction pressure and the crystallite size of cobalt. The effects of these factors and their potential for synergy were explored simultaneously using multivariate DOE, with the yield of different hydrocarbon composition selectivity's as the measured responses. In the concept generation phase, optimization was based on the literature consulted, which proved to be an effective method for determining the optimization parameters. The detailed conceptual design included the generation of models using statistical methods and response surface models. Finally, the optimized design was validated using catalysts and parameters obtained during the optimization process, and this were compared to the output recorded in the theoretical modelling. The optimized parameters resulted in performance consistency, with the theoretical model for each group of hydrocarbons being validated by actual experiments. The established models were seen to characterize hydrocarbon distributions accurately and repeatedly over a wide range of reaction conditions (200–270 °C, 5–20 Bar, and 3–26 nm) using a cobalt-based catalyst. According to the detailed quantitative models developed, for higher C5+ production, 220 °C, 10 barg and 11 nm (cobalt crystallite) benchmark parameters were set to produce 19.3 % C1, 11.4 % C2–C4 and 69 % C5+ selectivity's. Comparative analysis showed a 1.9 %, 3.9 % and 0.3 % percentage difference between the theoretical output and the actual output of C1, C2–C4 and C5+, respectively.

Approval of estimating productivity of a versatile plasma bend cutting framework utilizing response surface methodology and desirability function

The goal of the research was to improve the Plasma Curve Cutting (PAC) method on AISI 304 tempered steel by using the response surface methodology (RSM) optimisation approach. The RSM was used to determine the relationship between the input variables (machining settings) and the output variables (quality of cut). The seven cut parameter features that were the focus of the study were material removal rate, surface roughness, chamfer, dross, correct inclination point, kerf width, and intensity of impacted zone. In the study, the machining parameters gas tension, cutting current, cutting velocity, and lockup hole were all considered. The experiment, which included 27 trials on AISI 304 tempered steel, was created using the Box-Behnken Plan (BBD). The results showed that the RSM was significantly influenced by the machining settings, and the optimisation technique was easy to implement and competitively priced. The results were then confirmed using an affirmation test. In conclusion, the study used the response surface technique to optimize the Plasma Curve Cutting process on AISI 304 tempered steel. The findings demonstrated that the cut quality was significantly influenced by the machining parameters, and the optimisation technique was a successful and effective way to improve the process.

Process optimization, antioxidant, antibacterial, and drug adjuvant properties of bioactive keratin microparticles derived from porcupine (Hystrix indica) quills.

A structural protein called keratin is often employed in the medical industry to create medication carriers. Process improvement, antioxidant, antibacterial, and adjuvant drug studies of synthetic bioactive keratin microparticles made from lipids and keratin derived from porcupine (Hystrix indica) quills are the main objectives of this study. After coating the keratin microparticles with lipids which were obtained from the same porcupine quills, the bioactive keratin microparticles were produced. The response surface technique was applied to optimize the conditions for extraction of the keratin protein and sizing of the keratin microparticles. An infrared spectroscopy was used to analyze the chemical shifts in compositions of keratin microparticles while the optical microscopy was used to measure the size of the keratin microparticles. The results of this work revealed that a yield 27.36 to 42.25% of the keratin protein could be obtained from porcupine quills. The keratin microparticles were sized between 60.65 and 118.87 µm. Through response surface optimization, mercaptoethanol and urea were shown to be the main variables which positively affected the yield and the size of the keratin protein. The lipid stacking on the keratin microparticles' surface was confirmed by infrared spectroscopy. The 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulphonate) assay confirmed the keratin microparticle's antioxidant activity of 29.83%. Compared to lipid alone, the antibacterial properties of the keratin microparticles against Escherichia coli-a gram-negative-and Staphylococcus aureus-a gram-positive-bacteria enhanced by up to 55% following the coating of the microparticles with the lipids. The pharmacological action against these bacterial species was further improved by the lipid-loaded erythromycin that was carried on the surface of keratin microparticles. This work has demonstrated the design and uses of the keratin microparticles obtained from porcupine quills for clinical applications.

Functional improvement of synbiotic yogurt enriched with Lacticaseibacillus rhamnosus and aloe vera gel using the response surface method

The response surface technique was applied to produce synbiotic yogurt containing Lacticaseibacillus rhamnosus and aloe vera gel (AVG) with high functionality (antioxidant and antimicrobial characters), superior physicochemical properties, and desirable sensory attributes. The experiments were planned around a central composite design (CCD) with two independent variables: AVG concentration (0–5%, w/w) and storage time (1–28 days). The AVG concentration and storage time significantly improved the viability of L. rhamnosus up to 7.9 cfu/g during the shelf life which is a practical limit for a probiotic. It enhanced the yogurt’s antioxidant and antipathogenic activity, proteolytic content, water-holding capacity, and sensory aspects. High concentrations of AVG reduced the yogurt’s desirable textural aspects (hardness and gumminess) except for firmness and adhesiveness and to some degree the sensory properties as well. The results showed that adding 5% AVG to probiotic yogurt produced a functional food with 68% desirability that retained its beneficial properties for at least 14 days under refrigerated storage.Graphical

African locust bean (Parkia biglobosa) seed coat: A source of phenolic compounds

Parkia biglobosa is a versatile plant species used extensively by local communities in arid Africa. The seeds of this plant are valued for their high polyphenol content, highlighting their therapeutic antioxidant, and anti-inflammatory, antimicrobial, antidiabetic and antihypertensive properties. The aim of this study was to optimize the conditions for the extraction of the polyphenol content of the seed coat of P. biglobosa. Five extraction factors, namely solvent concentration, time, temperature, solid-liquid ratio, and pH, were optimized using the response surface technique. The optimization screening design results showed that temperature, time and solvent concentration were the most important variables with significant effects on polyphenol yield in a two-stage Placket-Burman design (p0.05). Box Behnken and Response Surface Analysis were applied to further investigate the mutual interactions between these variables and determine the ideal values that give the highest possible phenolic yield. The results showed the following ideal extraction conditions: 45 °C temperature, 240 min extraction time and 47.5 % solvent concentration. The TPC value obtained under the ideal extraction conditions was 54.023 ± 2.05 mg GAE /g. The antioxidant activity results of the concentrates showed 72.389 % inhibition of 2, 2-diphenyl-2-picrylhydrazyl hydrate and antioxidant capacity of 80.96 ± 1.16 mg AA /g. The results of the study show that the model is suitable for maximizing polyphenol extraction from the dried seed coat of P. biglobosa, as there is good agreement between the laboratory experiments and the estimated values

Entropy optimization and response surface methodology of blood hybrid nanofluid flow through composite stenosis artery with magnetized nanoparticles (Au-Ta) for drug delivery application

Entropy creation by a blood-hybrid nanofluid flow with gold-tantalum nanoparticles in a tilted cylindrical artery with composite stenosis under the influence of Joule heating, body acceleration, and thermal radiation is the focus of this research. Using the Sisko fluid model, the non-Newtonian behaviour of blood is investigated. The finite difference (FD) approach is used to solve the equations of motion and entropy for a system subject to certain constraints. The optimal heat transfer rate with respect to radiation, Hartmann number, and nanoparticle volume fraction is calculated using a response surface technique and sensitivity analysis. The impacts of significant parameters such as Hartmann number, angle parameter, nanoparticle volume fraction, body acceleration amplitude, radiation, and Reynolds number on the velocity, temperature, entropy generation, flow rate, shear stress of wall, and heat transfer rate are exhibited via the graphs and tables. Present results disclose that the flow rate profile increase by improving the Womersley number and the opposite nature is noticed in nanoparticle volume fraction. The total entropy generation reduces by improving radiation. The Hartmann number expose a positive sensitivity for all level of nanoparticle volume fraction. The sensitivity analysis revealed that the radiation and nanoparticle volume fraction showed a negative sensitivity for all magnetic field levels. It is seen that the presence of hybrid nanoparticles in the bloodstream leads to a more substantial reduction in the axial velocity of blood compared to Sisko blood. An increase in the volume fraction results in a noticeable decrease in the volumetric flow rate in the axial direction, while higher values of infinite shear rate viscosity lead to a significant reduction in the magnitude of the blood flow pattern. The blood temperature exhibits a linear increase with respect to the volume fraction of hybrid nanoparticles. Specifically, utilizing a hybrid nanofluid with a volume fraction of 3% leads to a 2.01316% higher temperature compared to the base fluid (blood). Similarly, a 5% volume fraction corresponds to a temperature increase of 3.45093%.

Parametric, response surface, and adjoint optimizations of the underbody diffuser of a generic ground vehicle

SUMMARYIt is a known fact in the literature that diffusers improve vehicle aerodynamics in terms of lift and drag forces. However, their effectiveness and efficiencies are quite sensitive to the design parameters. In this article, the underbody diffuser of a generic ground vehicle, Ahmed body, was optimized via CFD software of Ansys Fluent, step by step with parametric, response surface, and discrete adjoint techniques, respectively. Three numerical models (parametric, response surface, and adjoint models) have been created considering optimum force output for each optimization method, and qualitative and quantitative assessments were made on these models to compare flow characteristics and force coefficients with the base model. As a result, force coefficients are lower by 48.6, 49.3, and 52.8 counts for CD, 499.6, 547.4, and 528.2 counts for CL at parametric, response surface, and adjoint optimization phases compared with the base model, respectively. It is observed that diffusers help to improve flow transition and relief underbody and reduce the airflow over the upperbody zone by directing it to the underbody. However, detailed quantitative assessments show that it comes out that the contribution of the underbody to total CD may increase due to lower pressure distribution diffuser upsweep caused by higher mass flow beneath the model. These results demonstrate the importance of effective utilization and further controlling of underbody flow when using an underbody diffuser.

Yield evaluation of rocoto pepper (Capsicum pubescens R and P) with application of calcium carbonate in greenhouses

Objective: To evaluate if the application of calcium carbonate on the soil and to the leaf influences the weight and number of fruits in rocoto pepper grown under greenhouse conditions. Design/Methodology/Approach: The study was carried out in the greenhouse of the Facultad de Ciencias Agrotecnológicas, of the Universidad Autónoma de Chihuahua. The Taguchi method was used to develop the 13 treatments, with two factors, five levels per factor, and five repetitions per treatment, using 65 plants under study. Data was analyzed using the quadratic response surface technique, fitting the surface to determine factor levels for optimal response. Results: Reducing soil CaCO3 by 9% and increasing leaf CaCO3 by 100% was necessary to obtain the highest weight in the three harvests (234.8 g). Findings/Conclusions: A rise in the number of rocoto peppers (from 59 to 70, in the three harvest periods) required an increase in the soil and foliar CaCO3 by 8.5% and 100%, respectively.

Robust metamodel-based simulation-optimization approaches for designing hybrid renewable energy systems

We propose two robust metamodel-based approaches for designing stand-alone hybrid renewable energy systems that combine conventional and renewable energy generators with battery storage. Since the cost and reliability functions of the stochastic system do not have closed-form expressions, they can only be estimated via simulation. In the response surface methodology, the simulation input/output data is used first to locally fit first-degree surrogate functions for each supply scenario to perform a stochastic gradient descent, before a second-degree function is fitted and optimized when the gradient becomes small. In contrast, the global response surface technique globally fits a convex quadratic surrogate function on the simulation input/output data, then uses its minimizer to iteratively refine the search space. To account for estimation errors, a distributional ambiguity set based on a linear ϕ-divergence function is constructed around the nominal probability distribution of supply scenarios, and the expected reliability-adjusted cost of the system is computed using the worst-case distribution in this set. The validity of the proposed approaches and the value of considering distributional ambiguity are demonstrated through a realistic case study of a remote community in Northern Ontario.