Optimization of the preparation process of Spirulina blended liquor and Spirulina fermented wine, analysis of volatile components and in vitro antioxidant study.

The optimal conditions were explored for the preparation of Spirulina blended liquor (SBL) and Spirulina fermented wine (SFW), respectively. The parameters obtaining highest alga polysaccharide were calculated by response surface methodology. The optimal conditions for SBL preparation were base liquor of 42% vol, ultrasonication time of 37-min and ultrasonic power of 80 W with polysaccharide content (PC) and alcohol content (AC) of 0.2181 g/L and 39.7% vol, respectively. In the case of SFW, optimum fermentation occurred at 22°C, with a 4% inoculum and 6-day period with PC and AC of 8.533 g/L and 11.2% vol, respectively. Headspace solid-phase microextraction-gas chromatography-mass spectrometry was used to quantitatively analyze the volatile components of SBL and SFW. There were 32 and 40 main aroma compounds in SBL and SFW, respectively. Volatile organic compounds, including α-ionone and ß-ionone, produced by Spirulina were detected in both SBL and SFW. Comparative evaluation of scavenging activity and total reducing power revealed the antioxidant capacity of SFW significantly outperformed that of SBL.

Optimized pyrolytic synthesis and physicochemical characterization of date palm seed biochar: unveiling a sustainable adsorbent for environmental remediation applications.

This study focuses on the optimization and comprehensive characterization of biochar synthesized from date palm seeds (DPS), a prevalent agricultural waste in arid regions. Using response surface methodology (RSM) with a central composite design (CCD), we optimized the pyrolysis process by investigating the effects of time (1-3 h) and temperature (600-900 °C) on critical properties such as specific surface area, pore volume, and yield. The optimized biochar, produced at 828 °C for 1.7 h, demonstrated a high specific surface area of 654.8 m2/g and well-developed microporosity. Characterization techniques, including XRD, FTIR, SEM-EDS, and BET analyses, revealed an amorphous carbon structure with graphitic domains, diverse surface functionalities, and a heterogeneous porous microstructure. The biochar's point of zero charge at pH 7.58 indicates its potential for selective adsorption of charged contaminants. The close agreement between RSM-predicted and experimental values for specific surface area (652.1 m2/g vs. 654.8 m2/g) and micropore volume (0.191 cm3/g vs. 0.190 cm3/g) validates the effectiveness of the model in optimizing biochar properties. This research highlights the potential of DPS-derived biochar as a sustainable adsorbent for environmental remediation, opening avenues for valorizing agricultural wastes and contributing to circular economy principles.

Magnetic chitosan supported copper particles as a heterogeneous catalyst for benzaldehyde glycol acetal reaction.

In this work, a series of magnetic chitosan (CS) supported-metal catalysts were successfully prepared for the acetalization of benzaldehyde (BzH) with ethylene glycol (EG). The structural properties of the catalysts were characterized by TEM, FT-IR, XRD, XPS, TGA-DTG, SEM-EDX and VSM. The results showed that Fe3O4-CS-Cu(20 %) catalyst possessed the best catalytic efficiency in all prepared catalysts due to its suitable acidity and excellent stability when they were utilized in the acetalization reaction to generate benzaldehyde glycol acetal. The response surface methodology based on Box-Behnken design was applied to optimize acetalization reaction conditions with the optimal yield of 96.26 % obtained via 3D surface diagram. The attractive feature of prepared catalysts was easy separation from solutions via an external magnetic field application. This work sheds light on the design of novel chitosan-supported metal catalysts which could be widely applied in acetalization industry.

Preparation and characterization of novel natural pigment-indicating film: Application in kiwifruit freshness monitoring.

The marketability of natural pigment-based indicator films is impeded by their weaker color rendering and stability compared with synthetic pigments. Here, we developed novel colorimetric indicators by blending polyvinyl alcohol (PVA) with carboxymethyl cellulose (CMC) and combining alizarin and curcumin. Compared with the individual materials, the PVA and CMC composite films demonstrated superior thermal stability and water resistance. The manufacturing process of these colorimetric indicators was optimized using response surface methodology. The optimum conditions were as follows: PVA at 3.92 g/100 mL; plate pour amount, 48.6 mL; pigment content, 5.8 g/100 mL; pigment ratio, 0.76. The optimized film showed a robust response to CO2 (a color difference of 65.06 ± 2.43). The color difference of the optimized film improved by 98.5 % and 16.86 % for kiwifruit stored at room and low temperatures, respectively. This substantial color change aids in identifying the optimal consumption window for kiwifruit, boosting indicator precision and kiwifruit freshness accuracy.

Monomer production from supercritical ethanol depolymerization of PET plastic waste using Ni-ZnO/Al2O3 catalyst.

Plastic waste poses a serious threat to the global environment, with recycled polyethylene terephthalate (PET) plastic accounting for a considerable portion. The application of supercritical ethanol depolymerization technology presents an effective method for recycling PET waste. This study investigated using Ni as an additive to enhance the catalytic activity of ZnO/Al2O3 catalyst for PET waste depolymerization. The effects of different catalysts, catalyst dosage, reaction temperature, and reaction time on PET waste depolymerization were studied using the single-factor controlled variable method. The results showed that the 3Ni-ZnO/Al2O3 was the optimal catalyst, and under the optimal conditions with catalyst dosage of 4 %, reaction temperature of 260 °C, and reaction time of 60 min, the depolymerization efficiency of PET waste could reach 100 %, with the highest yields of diethyl terephthalate (DET) and ethylene glycol (EG) of 93.6 % and 90.2 %, respectively. Response surface methodology (RSM) was used to optimize the operating conditions to obtain the highest monomer yields. The predicted optimal parameters from RSM were as follows: reaction temperature = 262.8 °C, reaction time = 63.2 min, catalyst dosage = 3.8 wt%, with the predicted highest DET and EG yields of 95.9 % and 90.7 %, respectively. The analysis of variance (ANOVA) results for DET and EG possessed the R2 values of 0.9921 and 0.9885, respectively, with p-values < 0.0001, indicating a good fit for the models. Furthermore, after five times reuse, the 3Ni-ZnO/Al2O3 catalyst still exhibited good catalytic activity and stability. In conclusion, this study offers a clean, green, and sustainable alternative to recycling plastic waste.

Optimizing oxytetracycline removal from aqueous solutions using activated carbon from barley lignocellulosic wastes with isotherms and thermodynamic studies.

The excessive presence of antibiotics such as Oxytetracycline (OTC) in the wastewater has increased health problems due to their toxic impact on the aquatic ecosystem. Therefore, their removal has become an important topic. This study aims to produce high surface area-activated carbon derived from low-cost and environmentally friendly barley lignocellulosic wastes to remove OTC from aqueous solutions. The synthesized barley wastes-activated carbon (BW-AC) was characterized using Fourier-Transform Infrared spectroscopy, Thermal Gravimetric Analysis, X-ray diffraction analysis, N2 adsorption/desorption isotherms, and Scanning Electron Microscopy. A Central Composite Design under the Response Surface Methodology (CCD-RSM) was applied to optimize the operational parameters (adsorbent dosage, pH, OTC initial concentration, and contact time) affecting the adsorption capacity as the response factor. The optimum condition of OTC adsorption by BW-AC was the adsorbent dosage of 16.25 mg, pH of 8.25, initial concentration of 62.50 mg/L, and contact time of 23.46 min. An analysis of variance (ANOVA) was performed to investigate the significance of the designed quadratic model and evaluate the parameters interactions. The linear regression coefficient (R2) of 0.975 shows a good correlation between predicted and actual results. The adsorption isotherms were used to determine the contaminant distribution over the adsorbent surface, and the equilibrium data was best described by the Freundlich isotherm due to the R2 value of 0.99 compared to other isotherms and ß parameter of 0.23 in Redlich-Peterson equation. Moreover, the n value of 1.25 in Freundlich equation and E value of 0.31 in Dubinin-Radushkevich equation indicates a physical nature of adsorption process. According to the equations results, the maximum adsorption capacity of BW-AC for OTC removal was 500 mg/g, based on the Langmuir isotherm equation. In addition, the thermodynamic studies indicated an endothermic process based on the 0.31 value of ΔH° and spontaneous nature due to the negative amount of ΔG° within the temperature range of 288-318 K. Consequently, the prepared BW-AC can be deemed as a highly effective adsorbent with a large surface area, resulting in significant capacity for removing OTC. This synthesized BW-AC can serve as an environmentally friendly adsorbent for affordable wastewater treatment and is poised to make valuable contributions to future research in this field.

Extradyadic stress as a barrier to sexual activity in couples? A dyadic response surface analysis.

Sexuality is integral to most romantic relationships. Through stress spillover, however, factors such as individually experienced stress outside of the relationship (i.e., extradyadic stress) can negatively impact sexuality. In this study, we explored how a possible (mis)matching of both partners' levels of extradyadic stress is related to sexual activity and tested for gender differences. Analyzing 316 mixed-gender couples from Switzerland, we employed Dyadic Response Surface Analysis to assess how extradyadic stress is associated with sexual activity. Our results showed that extradyadic stress was positively linked to sexual activity for women (in general) and men (in the case of matching stress levels). As this result was surprising, we conducted additional exploratory analyses and split the measure of sexual activity into (1) exchange of affection and (2) eroticism (petting, oral sex, and intercourse) and controlled for age. Results from this second set of analyses showed that for women, matching stress levels were associated with higher exchange of affection, whereas men's exchange of affection was higher if men reported higher stress levels than women. Notably, after accounting for age, the link between stress and eroticism dissipated. Our findings suggest that exchange of affection may serve as a coping mechanism for stress, with gender influencing this dynamic. However, future research investigating stress and sexual activity should consider additional factors such as age, relationship satisfaction, stressor type, and stress severity.

Establishment of a Generalizable Industrial Crop Model for Microwave Extraction of Unsaturated Fatty Acids.

To explore the relationship between unsaturated fatty acid (UFA) content and parameters for microwave extraction, multimaterial and multiparameter testing was conducted in which five kinds of materials with different UFA contents (potato, wheat, corn, soybean, and peanut) were selected for the experiment. Four factors, namely, extraction temperature (X 1), extraction time (X 2), proportional volume of acetone (X 3), and liquid-to-solid ratio (X 4), were screened for their significant effects by using Prob > |T| values from the Plackett-Burman experiment. A microwave extraction orthogonal experiment with four factors and five levels was designed separately using Design-Expert 8.05 software and them concentrated. Microwave-accelerated methyl esterification was then performed, and the UFA content was determined via gas chromatography (flame ionization detector). The optimal extraction conditions (X 1, X 2, X 3, X 4) and the optimal UFA content of potato were 80.68°C, 10.74 min, 0.80, 3.25 mL × g-1, 1.08%; wheat: 80.81°C, 10.54 min, 0.80, 20.91 mL × g-1, 2.26%; corn: 81.18°C, 9.93 min, 0.80, 50.94 mL × g-1, 6.89%; soybean: 82.07°C, 9.07 min, 0.80, 93.87 mL × g-1, 15.81%; and peanut: 83.12°C, 8.11 min, 0.80, 168.70 mL × g-1, 33.07%. Then, the optimization results for the five kinds of materials were synthesized by Origin 8.0 software, the fitting degree of the cubic model with the four extraction factors was the highest, the determination coefficients were 0.9984, 0.9991, 0.8953, and 0.9989, the residual sums of squares were 0.2888, 0.1587, 0.8265, and 0.1864, and the correlation coefficients are ideal. The stability and accuracy of the model were verified by the orthogonal experiment of UFA extraction from rice, and the correlation coefficient between the predicted value and the actual value of the orthogonal experiment was 0.9998. This study systematically collates the optimal parameters for microwave extraction of UFA content in different crops from the perspective of multimaterial and multiparameter, which can provide a large amount of detailed basic data for microwave extraction technology.

How the designed processing parameters affect the liquid mixture density and viscosity of the tretinoin-loaded niosomes at different temperatures?

The current study was conducted to present novel thermophysical data on tretinoin-loaded niosomes paired with a combination of span 60 and tween 80. Measurements were carried out to analyze the liquid mixture density and viscosity of the mentioned multilayered structures for the first time, with consideration given to the diverse molecular weights of surfactants and various stabilizers at different temperatures. Through the application of equations of state, this study has the ability to set the stage for thermodynamic modeling of solutions that involve niosomes, presenting a promising avenue for further research. So, tretinoin-loaded formulations were prepared by investigating the effects of different co-surfactants, including cholesterol or dodecanol, as well as the impact of surfactant molecular weight limited to 650.525-1090.175 g mol-1. This novel investigation was conducted to assess the superior stabilizing capabilities of dodecanol in comparison to cholesterol, with a specific emphasis on optimized vesicle size, highest incorporation efficiency, and lowest zeta potential. In particulars, the response surface methodology (RSM) was applied to optimize the operative factors and the number of experiments. The experimental evidence clearly indicates that the use of dodecanol in the manufacturing process significantly improves the stability of niosomes, while the inclusion of cholesterol leads to higher liquid mixture density and viscosity in the prepared niosomes.

Optimization of ventilation efficiency in tunnel-type underground spaces using response surface methodology: a case study of Yunlong Mountain civil defense in Xuzhou.

Civil defense projects, designed as wartime underground spaces, often lack effective natural ventilation and have considerable depth, which complicates their use as public spaces in peacetime. However, the application of passive ventilation technologies can create effective airflow channels within these structures, significantly enhancing ventilation efficiency and thus improving the overall thermal comfort level. For this study, air age, along with average wind speed, temperature, and relative humidity as stipulated by the "Requirements for Environmental Sanitation of Civil Air Defense Works during Peacetime Use" (GBT 17216-2012), were selected as evaluation metrics. This paper compares the ventilation effectiveness between single ventilation shafts and multiple ventilation shafts under positive and negative pressure conditions in underground civil defense structures. The results indicate that negative pressure ventilation in multiple shaft configurations performs optimally across various ventilation approaches. Subsequently, the Response Surface Methodology (RSM) was utilized to further optimize the positioning of multiple ventilation shafts. The study examined the impact of three ventilation shaft locations on average wind speed, temperature, relative humidity, and air age, leading to an optimized design. Specifically, the optimal positions are 54.76 m for Shaft A, 51.45 m for Shaft B, and 79.85 m for Shaft C, achieving an average wind speed of 0.222 m/s, a temperature of 26 °C, a relative humidity reduction to 85.47%, and an average air age of 10.57 s. This research provides practical insights for the optimization of ventilation in underground civil defense facilities.

Electrokinetic remediation of cadmium-contaminated soil using polarity reversal method: Optimization analysis and mechanism exploration.

Electrokinetic remediation (EKR) has been applied for in-situ removal of Cd from contaminated soil, and the EKR enhanced with polarity reversal has achieved a higher Cd removal efficiency. However, the migration and accumulation mechanisms of Cd in the EKR process have not been investigated. In this paper, the cross-impacts of the voltage gradient, citric acid concentration in the electrolyte, and polarity reversal frequency on the removal efficiency by EKR of Cd and the optimization conditions were investigated. The migration and accumulation mechanisms of Cd were explored by analyzing the changes in electrokinetic process parameters, experimental phenomena, and X-ray diffraction (XRD) analysis. The results showed that the maximum removal efficiency of Cd reached 82.26%. The optimal conditions were determined by fitting the RSM model using the BBD design. In the EKR experiment with polarity reversal, Cd accumulated mainly in the middle part of the soil, attributed to the formation of chemical precipitation focusing area caused by soil pH transition, ion-induced potential gradient well trapping effect (IIPGWTE), or soil compaction induced by water loss. In conclusion, the various parameters have cross-impacts on the EKR of Cd-contaminated soil, and efficient in-situ removal of Cd from the contaminated soil can be achieved by adjusting the parameter conditions.

Maximizing polyphenol yield: ultrasound-assisted extraction and antimicrobial potential of mango peel.

This study investigated the ultrasound-assisted extraction (UAE) techniques used to enhance the polyphenols and antioxidants of mango peel extract (MPE). Additionally, it explored the bacteriostatic activity of MPE against various microorganisms. The UAE method was optimized using response surface methodology (RSM) at different times, temperatures, and ratios, with optimal conditions found to be 35 minutes, 45 °C, and a 1:35 ratio. The optimized yield results for total polyphenol content (TPC) were 17.33 ± 1.57 mg GAE/g, total flavonoid content (TFC) was 12.14 ± 0.29 mg QE/g, and radical scavenging activity (RSA) was 72.11 ± 2.19%. These response models were extremely significant with p-values less than 0.05. MPE showed selective effectiveness against Bacillus cereus, Geobacillus stearothermophilus, and Escherichia coli (E. coli). The results highlight the potential of mango peel as a sustainable source of bioactive compounds, contributing to waste reduction in the food industry and the development of natural antimicrobial agents. This study contributes to further research on the application of MPE in processed foods.

Mitigating psychological distress in the workplace: The role of perceived insider status in leader-follower cognitive style congruence.

This study examines the impact of leader-follower cognitive style congruence on employee psychological distress, with a specific emphasis on the mediating role of perceived insider status. Using data from a major financial institution in China, the findings reveal that higher cognitive style alignment between leaders and followers is associated with a significant reduction in employee psychological distress. Grounded in Conservation of Resources (COR) theory, the study demonstrates that cognitive style congruence enhances predictability and facilitates the conservation of psychological resources, effectively mitigating psychological distress. Notably, employees led by intuitive leaders report lower distress levels compared to those led by analytic leaders. These results underscore the critical importance of cognitive style congruence in fostering employee well-being and offer actionable insights for enhancing organizational practices.

Performance analysis, statistical modeling, and multiple response optimization of a novel fixed-bed quartz reactor packed with Ba-Pt@γ-AL2O3 using response surface methodology.

In the present study, a novel fixed-bed continuous reactor with a preheating chamber was designed to be utilized for the practical application of removal studies of dangerous pollutants, especially NOX removal by NOX Storage Reduction (NSR) catalysts on a laboratory scale. The reactor's design and operational parameters, including outer wall temperature (50-600 °C), volumetric flow rate (0.3-3 L/min), wall temperature time (0.16-10 min), and granule surface area inside the preheating chamber (0-270 cm2), were statistically modeled and optimized using Response Surface Methodology (RSM). For more logical and effective parameter optimization, the ratio of gas and catalyst temperatures and pressure drop to the reactor outer wall temperature (GT/ROWT, CT/ROWT, and PD/ROWT) were also included in the optimization process. Experimental results showed that gas temperature, catalyst temperature, and pressure drop ranged from 31 to 177 °C, 51-585 °C, and 7-153 Pa, respectively. Optimal conditions were determined to be an outer wall temperature of 230 °C, a volumetric flow rate of 3 L/min, a wall temperature time of 0.16 min, and a granule surface area of 67.3 cm2. The results demonstrated that outer wall temperature, flow rate, time, and surface area of granules have significant and interaction effects on the responses and should be considered when researchers assess the removal efficiency of thermal catalysts.

Enhanced reducing leachate pollution index through electrocoagulation using response surface methodology.

Addressing the urgent need to effectively manage landfill leachate as a harmful flow for human health and the environment, this research investigates how electrocoagulation (EC) processes could alleviate the pollution potential of leachate. So far, no experimental study has been carried out on reducing the leachate pollution index (LPI) under the EC process. For this purpose, in this novel research, the LPI was utilized as a key metric to evaluate the efficiency of the treatment process. Central Composite Design (CCD) as a subset of Response Surface Methodology (RSM) was applied to enhance the LPI parameters decreasing percentage. The data were analyzed by analysis of variance and multivariate regression and 3D plots assessed variable interactions. Under optimal conditions, it showed removal of 97.48 % for COD, 91.42 % for BOD5, 98.52 % for N-NH3, and 91.6 % for TDS. Significant reductions were observed in 94.81 % TKN, 87.20 %, 82.80 %, 96.66 %, and 99.28 %, 99.18 %, and 96.56 % for TKN, Cl-, CN-, As, Cr, Zn, and Ni, respectively. Moreover, the kinetics of COD removal indicated that it follows a first-order model. Thus, based on experimental results, the LPI of raw leachate decreased from 38.06 to 7.22 (81 % decrease) under the EC treatment method. The study indicated that the EC treatment method successfully reduced leachate pollution and met the leachate discharge standard.

Blended natural and synthetic coagulants for the COD and BOD removal from surface water; optimization by response surface methodology: The case of Gibe river.

A novel wastewater treatment method is presented in this study. It combines natural coagulants derived from watermelon seeds with the commonly used synthetic coagulant alum. This research demonstrates a remarkable synergy between these two coagulants in removing nutrients from Gibe River wastewater. Combining natural and chemical coagulants often improves water treatment by enhancing particle destabilization, accelerating floc formation, and broadening the range of removable contaminants, resulting in lower chemical dosage requirements. The optimal mixing ratio, found to be 1 part watermelon seed coagulant to 3 parts alum, leads to improved treatment efficiency. At this ratio, the process achieves impressive removal rates: 98.26 % for total dissolved solids (TDS), 96.10 % for biochemical oxygen demand (BOD), and 95.26 % for chemical oxygen demand (COD). These findings not only validate the use of watermelon seeds as a coagulant but also highlight the combined approach's environmental and economic benefits. This integrated method offers a more sustainable and cost-effective solution for wastewater treatment.

Numerical investigation of MHD mixed convection in an octagonal heat exchanger containing hybrid nanofluid.

Nowadays, the advancement of heat transmission for the heat exchanger device is an important field of research for many researchers. In this work, a numerical study has been conducted to investigate the thermal performance of a mixed convective flow through the octagonal heat exchanger covered by hybrid nanofluid (Cu-TiO2-H2O). A magnetic field has been introduced inside the cavity to investigate the mixed convective hydrodynamics heat flow characteristics. The nanofluid cores absorb/release energy to manage heat transmission by increasing or decreasing inside the cavity domain as the host fluid and dispersed hybrid nanofluid circulate within the cavity. After transforming the governing equations into a generalized, non-dimensional formulation, the finite element approach is utilized to solve the associated equations. Additionally, response surface methodology is also applied to test the responses of the associated factors. Heat transport was examined in relation to the effects of nanofluids fusion temperature, boundary wall properties, Reynolds number, Hartmann number and nanoparticle volume fractions. The outcomes of this study are analysed by measuring streamline profiles, isotherms, average Nusselt number, velocity profile, and 2D and 3D response surfaces of the computational domain. The underlying flow controlling parameters for instance Reynolds number (10 ≤ Re ≤ 200), Hartmann number (0 ≤ Ha ≤100), and nanoparticle volume fractions (0 ≤ Ï• ≤ 0.1), the influences have been considered. The findings also reveal that the thermal performance is being boosted due to augmentation of Re and ϕ, but reverse behavior is noticed for Ha. Furthermore, the response surfaces obtained from response surfaces methodology express that the Re and ϕ have shown positive influence, and Ha has shown negative influence on Nuav. Utilizing a hybrid nanofluid of Cu-TiO2-H2O increases the heat transfer capacity of water to 25.75 %. Moreover, the findings could guide to design of a mixed convective heat exchanger for industrial purposes.

Omnidirectional soft pneumatic actuators: a design and optimization framework.

Introduction: Soft pneumatic actuators (SPAs) play a pivotal role in soft robotics due to their unique characteristics of compliance, flexibility, and adaptability. There are plenty of approaches that examine the modeling parameters of SPAs, aiming to optimize their design and, thus, achieve the most advantageous responses. Current optimization methods applied to SPAs are usually performed individually for each design parameter without considering the simultaneous effect all parameters can have on the output performance. This modeling shortcoming is essential to be addressed since customized SPAs are used in a variety of applications, each with different output requirements. Methods: This study provides a generalized design optimization framework for modeling the SPA performance for their motion profiles, the produced strain energy while being deformed, and their stiffness characteristics. Utilizing experimentally validated finite element methods, all geometrical and material parameters of the models are investigated in response surface methodology optimization using the central composite design approach. Results: The results showcase the entire design space of omnidirectional SPAs, along with their output performance, providing guidelines to the end user for design optimization. Discussion: The offering of this modeling process for SPAs can be adapted to the demands of any potential application and ensure the best performance with respect to the required output responses.

Investigating the Influence of Additive Manufacturing and Ultrasonic Coating Parameters on Biopolymeric Scaffold Performance Using Response Surface Methodology.

Triply periodic minimal surface (TPMS) scaffolds have gained attention in additive manufacturing due to their unique porous structures, which are useful in biomedical applications. Unlike metallic implants that can cause stress shielding, polymeric scaffolds offer a safer alternative. This study is focused on enhancing the compressive strength of additive-manufactured polylactic acid (PLA) scaffolds with a diamond structure. The response surface methodology (RSM)-based experimental design was developed to study the influence of printing parameters. The fused deposition modeling (FDM) process parameters were optimized, achieving a compressive strength of 56.2 MPa. Subsequently, the scaffolds were fabricated at optimized parameters and underwent ultrasonic-assisted polydopamine coating. With the utilization of the RSM approach, the study examined the effects of ultrasonic vibration power, coating solution concentration, and submersion time on compressive strength. The optimal coating conditions led to a maximum compressive strength of 92.77 MPa-a 65.1% improvement over the uncoated scaffold. This enhancement is attributed to the scaffold's porous structure, which enables uniform coating deposition. Energy-dispersive x-ray spectroscopy confirmed the successful polydopamine coating, with 10.64 wt% nitrogen content. These findings demonstrate the potential of ultrasonic-assisted coating in improving the mechanical properties of PLA scaffolds, making them suitable for biomedical applications.

Impact of Toolpath Pitch Distance on Cutting Tool Nose Radius Deviation and Surface Quality of AISI D3 Steel Using Precision Measurement Techniques.

The selection of the right tool path trajectory and the corresponding machining parameters for end milling is a challenge in mold and die industries. Subsequently, the selection of appropriate tool path parameters can reduce overall machining time, improve the surface finish of the workpiece, extend tool life, reduce overall cost, and improve productivity. This work aims to establish the performance of end milling process parameters and the impact of trochoidal toolpath parameters on the surface finish of AISI D3 steel. It especially focuses on the effect of the tool tip nose radius deviation on the surface quality using precision measurement techniques. The experimental design was carried out in a systematic manner using a face-centered central composite design (FCCD) within the framework of response surface methodology (RSM). Twenty different experiment trials were conducted by changing the independent variables, such as cutting speed, feed rate, and trochoidal pitch distance. The main effects and the interactions of these parameters were determined using analysis of variance (ANOVA). The optimal conditions were identified using a multiple objective optimization method based on desirability function analysis (DFA). The developed empirical models showed statistical significance with the best process parameters, which include a feed rate of 0.05 m/tooth, a trochoidal pitch distance of 1.8 mm, and a cutting speed of 78 m/min. Further, as the trochoidal pitch distance increased, variations in the tool tip cutting edge were observed on the machined surface due to peeling off of the coating layer. The flaws on the tool tip, which alter the edge micro-geometry after machining, resulted in up to 33.83% variation in the initial nose radius. Deviations of 4.25% and 5.31% were noted between actual and predicted values of surface roughness and the nose radius, respectively.