Search Results (24)

To enhance the aerodynamic performance of organic Rankine cycle (ORC) turbines under increasing energy demands, surrogate-based optimization was applied to a 100 kW ORC turbine rotor. Four representative surrogate models—a radial basis neural network (RBNN), Kriging, response surface approximation (RSA), and a PRESS-based weighted (PBW) ensemble—were comparatively evaluated under identical numerical conditions. Independent optimizations of the first- and second-stage rotors enabled an examination of how different design variable space characteristics influenced surrogate predictive behavior. A fractional factorial sampling strategy was used to construct the training dataset, and learning curve analysis was conducted to assess sample size adequacy. Sensitivity estimation revealed distinct response surface characteristics between stages, allowing the interpretation of variations in surrogate stability. In both stages, geometric modifications were primarily concentrated near the outlet blade angle, identified as a dominant variable influencing efficiency. CFD validation confirmed that surrogate-based exploration successfully identified improved rotor geometries. Flow-field analysis indicated reduced entropy generation near the trailing edge region, suggesting the mitigation of aerodynamic losses. The results demonstrate that surrogate-based optimization can reliably improve turbine performance within a bounded design space, while the relative effectiveness of surrogate models depends on the sensitivity structure of the underlying problem. Full article

Drought and soil nutrient deficiency are critical constraints on plant growth and ecological restoration in desert steppes; however, the interactive mechanisms between arbuscular mycorrhizal fungi (AMF) and phosphorus fertilization remain poorly elucidated. To investigate the regulatory mechanisms governing root system architecture (RSA) remodeling and regrowth capability in Agropyron under drought stress, a controlled experiment was conducted using two genotypes: Inner Mongolia (NM) and Xinjiang (XJ). The experimental design comprised three water regimes (70%, 50%, and 30% field capacity [FC]), two P levels (P0, P1), and two inoculation treatments (A0, A1). The results indicated the following: (1) Although drought significantly inhibited Agropyron growth, the combined application of AMF and P (A1P1) induced a highly significant synergistic effect, augmenting total aboveground biomass by 66.08–160.58% compared to the control. This synergy exhibited distinct “environmental dependency,” being most pronounced under moderate drought conditions (50% FC). (2) Mechanistic analysis revealed that A1P1 optimized RSA by significantly increasing total root length, root surface area, and root volume (e.g., total root length increased by 281.4–375.1% under severe stress), thereby enhancing water and nutrient acquisition. (3) The A1P1 treatment significantly mitigated the decline in regrowth potential induced by successive clipping, sustaining a higher tiller number (increasing by up to 1.8-fold in the 3rd clipping). (4) The XJ genotype was characterized by higher basal biomass and root investment “high-yield phenotype”, whereas the NM genotype demonstrated greater sensitivity to AMF-P regulation “highly responsive phenotype”. In conclusion, the synergistic interaction between AMF and P mitigates drought stress by reshaping RSA and enhancing regrowth capability, providing a theoretical basis for the efficient management of arid grasslands. Full article

The adult child–parent relationship is a key source of emotional support across adulthood and older age. This study takes a dyadic, attachment-based perspective to examine how (dis)similarities in attachment orientations between older parents and adult children relate to the emotional support they provide each other. A total of 104 adult child–parent dyads (M parents’ age = 67.85; M adult children’s age = 36.18) participated. Structural Equation Modeling (SEM) and Response Surface Analysis (RSA) were used to assess how dyadic (dis)similarities in attachment anxiety and avoidance are associated with own support provision. Both parents and adult children provided greater emotional support when their attachment insecurity was at low levels. Support also increased when the partner showed higher insecurity but differed across generations: parents offered more support when the child’s anxiety or avoidance exceeded their own, even at own high levels of insecurity, whereas children supported insecure parents only when their own insecurity was relatively low. Attachment-based processes in the adult child–parent bond serve as a source of emotional connection, operating differently across generations: parents can adapt caregiving to meet children’s needs, while children’s support is more constrained by their own attachment insecurity. Full article

This study explains repeat purchase intentions on e-commerce platforms as a problem of fit between what the interface signals (Customer Service Orientation, CSO) and what the system delivers (Internal Service Quality, ISQ). Using survey data from Chinese platform users (N = 605), second-order polynomial models with response-surface analysis (RSA) show that repurchase intention rises when CSO and ISQ increase together, exhibits diminishing returns at high joint levels, and declines as the two diverge. A structural equation model (SEM) provides cross-sectional evidence consistent with mediation via pride in membership; when CSO and ISQ are modeled jointly with pride, CSO shows the larger direct association with repurchase. We also find that trust and security awareness initiatives act as a structural assurance that flattens the CSO–ISQ surface, attenuating both slopes and curvatures. Taken together, the results advance a fit-based account of digital service in which outcomes depend on the alignment of interface signals with executional capability and operate through identity-based pride, with platform-level assurances bounding marginal returns. Managerially, the findings imply prioritizing the closure of CSO–ISQ gaps and reducing execution variance before pursuing further single-dimension upgrades. Full article

Based on the cumulative risk model and cognitive appraisal theory, this study examined the complex relationships between economic pressure, emotional neglect, and anxiety among left-behind children (LBC), focusing on the mediating role of perceived discrimination and nonlinear risk patterns. A cross-sectional survey was conducted with 618 LBC (aged 11–16 years) using standardized scales. Polynomial regression combined with Response Surface Analysis (RSA) was utilized to analyze congruence and incongruence effects. The results revealed that under congruent conditions, the association of economic pressure and emotional neglect with anxiety showed a marginally significant nonlinear accelerating trend, whereas their prediction of perceived discrimination followed a linear trend. Under incongruent conditions, emotional neglect demonstrated a stronger independent predictive effect on anxiety compared to economic pressure. Furthermore, perceived discrimination partially mediated the relationships between these risk factors and anxiety. These findings validate the cumulative risk model within the LBC context, demonstrating that risk factors operate in complex, non-additive ways. This highlights the necessity for differentiated interventions and suggests that reshaping LBC’s subjective cognitive appraisals is key to reducing anxiety. Full article

Cocoa pod husk (CPH) is a potential material to produce value-added products. The objective of this study was to optimize the microwave-assisted hydrothermal pretreatment (MA-HTP) of CPH and CPH hemicellulose (HMC-CPH) using only water as the extraction medium, in combination with response surface analysis (RSA), Box–Behnken design (BBD), and proton nuclear magnetic resonance identification and quantification (¹H NMR Qu) to provide an efficient protocol for the extraction of mono- and disaccharides, as a novel method for which no precedent was found. The methodology consisted of 15 CPH MA-HTPs and 15 HMC-CPH MA-HTPs (triplicate) designed by RSA-BBD; the experimental variables were time, temperature, and power, and the response was the concentration of extraction products. Glucose, sucrose, and fructose were identified as products of the extractions by ¹H NMR. With 95% confidence, higher sucrose content was determined for CPH (45.62%) compared to HMC-CPH (17.34%), high fructose content for both CPH and HMC-CPH (37.88% and 35.37%, respectively), and minimal glucose concentrations were obtained in both CPH and HMC-CPH (4.57% and 0.93%, respectively). Using RSA-BBD, optimal temperature, power, and time points were predicted for glucose CPH: 135.4 °C, 180.6 W, and 5.8 min; sucrose: 154.3 °C, 256.3 W, and 20. 2 min; fructose 129.5 °C, 173.8 W, and 5.27 min. For HMC-CPH, the optimal conditions were as follows: glucose: 142.2 °C, 204.4 W, and 10.5 min; sucrose: 148.8 °C, 215.6 W, and 14.3 min; fructose: 151.6 °C, 231.6 W, and 13 min. Full article

In the process of operating subsoiling implements on sloping red soil in Southwest China, the subsoiler tip faces significant challenges due to strong soil adhesion and severe compaction. By employing engineering bionics, integrating bionic geometric structures and surfaces, this study focuses on the subsoiler tip and designs four types of bionic geometric surface structures: bionic convex hull, bionic micro-spike convex hull, bionic scales, and bionic micro-spike scales. Finite element force analysis and discrete element simulation experiments reveal that bionic surfaces and geometric structures exhibit significant advantages in terms of total deformation, equivalent elastic strain, and stress. These structures are less prone to deformation and fracture under loads, demonstrating a stronger bearing capacity. A discrete element simulation analysis indicates interference phenomena among the subsoilers during multi-subsoiler operations. Based on bionic multi-subsoiler implements, optimized designs were developed through discrete element simulations and soil bin tests. The optimized bionic multi-subsoiler implement features a micro-spike convex hull surface, with micro-spike scale surfaces arranged equidistantly along the edge corners of the shovel face: six on each side wing and three in the middle. The optimal operating parameters were a subsoiling speed of 1.25 m/s, an entry angle of 23.917°, and an entry depth of 280.167 mm. The relative errors between the simulated and experimental values for the soil looseness and soil disturbance coefficients were 19.7% and 18.1%, respectively. The soil bin test results showed soil looseness and soil disturbance coefficients of 19.5% and 17.6%, respectively. At this point, the resistance reduction and wear resistance performance were optimal. This study proposes a bionic design approach for reducing resistance and enhancing wear resistance during the subsoiling process in the viscous red soil of Southwest China, providing a reference for the design and development of new equipment for working in this soil environment. This study is the first to implement a composite biomimetic surface—combining crayfish-like micro-spike convex hulls and sandfish-like micro-scale scales—on multi-shank subsoiler tips, and to validate it using FEA, DEM, and soil tank testing. Under an optimized configuration and operating conditions, the mean particle disturbance velocity increased from 1.52 m/s to 2.399 m/s (+57.8%), and the simulation/experiment relative errors for the soil loosening and disturbance coefficients were approximately 1.03% and 2.84%, respectively. These results demonstrate an engineering-acceptable trade-off between disturbance efficiency and wear resistance and indicate a clear potential for industrial application. Full article

Fermented plant-based beverages represent promising functional foods due to their content of bioactive compounds (polyphenols, prebiotics) and viable probiotic microorganisms. Sprouted buckwheat is a rich source of bioactives and nutrients, which makes it a promising ingredient for the development of synbiotic formulations. This study aimed to optimize the fermentation process of a plant-based beverage composed of germinated buckwheat, honey, inulin, and Lactiplantibacillus plantarum (Lpb. plantarum), using Box–Behnken experimental design (BBD) and Response Surface Methodology (RSM) tools. The influence of three independent variables (inulin, honey, and inoculum concentration) was evaluated on five key response variables: total polyphenol content, flavonoid content, antioxidant activity (RSA%), pH, and starter culture viability. The optimal formulation—comprising 3% inulin, 10% honey, and 6.97 mg/100 mL inoculum—demonstrated functional stability over 21 days of refrigerated storage (4 °C), maintaining high levels of antioxidants and probiotic viability in the fermented beverage. Kinetic analysis of the fermentation process confirmed the intense metabolic activity of Lpb. plantarum, as evidenced by a decrease in pH, active consumption of reducing sugars, and organic acids accumulation. Full article

Internal drainage is crucial for preventing water damage in pavement structures. Pervious concrete is widely used in road projects due to its excellent drainage capacity, scour resistance, and durability. This study optimizes the mix design of pervious concrete by considering gradation (three levels), water-cement ratio (0.3, 0.35, 0.4), and target porosity (15%, 18%, 21%). The 7-day unconfined compressive strength, permeability coefficient, and elastic modulus were selected as evaluation indices. Response Surface Analysis (RSA) and Analysis of Variance (ANOVA) were applied to determine the optimal mix proportion. Scour resistance tests were conducted based on the optimal mix design to analyze the effects of scour time, frequency, and impact force on strength and modulus variation. The results indicate that the optimal mix ratio is Grade I, with a water-cement ratio of 0.35 and a target porosity of 18%. This yielded a 7-day compressive strength of 5.1 MPa, a rebound modulus of 2170.7 MPa, a permeability coefficient of 49 mL/s, and a hydraulic conductivity of 0.0027–0.0054 m²/s. Under standard scour conditions, compressive strength, splitting strength, dynamic rebound modulus, and splitting rebound modulus decreased by 16%, 33%, 40%, and 16%, respectively. Compared to cement-stabilized gravel (53% strength loss), pervious concrete exhibited lower strength loss (16%) due to its interconnected porosity, which mitigates internal water pressure during scouring. Overall, pervious concrete outperforms cement-stabilized gravel in mechanical properties and scour resistance, providing theoretical guidance for engineering applications. Full article

Pretreatment of lignocellulosic biomass remains the primary obstacle to the profitable use of this type of biomass in biorefineries. The challenge lies in the recalcitrance of the lignin-carbohydrate complex to pretreatment, especially the difficulty in removing the lignin to access the carbohydrates (cellulose and hemicellulose). This study had two objectives: (i) to investigate the effect of reactive extrusion on lignocellulosic biomass in terms of delignification percentage and the structural characteristics of the resulting extrudates, and (ii) to propose a novel pretreatment approach involving extrusion technology based on the results of the first objective. Two types of biomasses were used: agricultural residue (corn stover) and forest residue (black spruce chips). By optimizing the extrusion conditions via response surface analysis (RSA), the delignification percentages were significantly improved. For corn stover, the delignification yield increased from 2.3% to 27.4%, while increasing from 1% to 25.3% for black spruce chips. The highest percentages were achieved without the use of sodium hydroxide and for temperatures below 65 °C. Furthermore, the optimized extrudates exhibited important structural changes without any formation of p-cresol, furfural, and 5-hydroxymethylfurfural (HMF) (enzymes and microbial growth-inhibiting compounds). Acetic acid however was detected in corn stover extrudate. The structural changes included the disorganization of the most recalcitrant functional groups, reduction of particle sizes, increase of specific surface areas, and the appearance of microscopic roughness on the particles. Analyzing all the data led to propose a new promising approach to the pretreatment of lignocellulosic biomasses. This approach involves combining extrusion and biodelignification with white rot fungi to improve the enzymatic hydrolysis of carbohydrates. Full article

Due to the genetic diversity between the mother and the fetus, heightened control over the immune system during pregnancy is crucial. Immunological parameters determined by clinicians in women with idiopathic recurrent spontaneous abortion (RSA) include the quantity and activity of Natural Killer (NK) and Natural Killer T (NKT) cells, the quantity of regulatory T lymphocytes, and the ratio of pro-inflammatory cytokines, which indicate imbalances in Th1 and Th2 cell response. The processes are controlled by immune checkpoint proteins (ICPs) expressed on the surface of immune cells. We aim to investigate differences in the expression of ICPs on T cells, T regulatory lymphocytes, NK cells, and NKT cells in peripheral blood samples collected from RSA women, pregnant women, and healthy multiparous women. We aim to discover new insights into the role of ICPs involved in recurrent pregnancy loss. Peripheral blood mononuclear cells (PBMCs) were isolated by gradient centrifugation from blood samples obtained from 10 multiparous women, 20 pregnant women (11–14th week of pregnancy), and 20 RSA women, at maximum of 72 h after miscarriage. The PBMCs were stained for flow cytometry analysis. Standard flow cytometry immunophenotyping of PBMCs was performed using antibodies against classical lymphocyte markers, including CD3, CD4, CD8, CD56, CD25, and CD127. Additionally, ICPs were investigated using antibodies against Programmed Death Protein-1 (PD-1, CD279), T cell immunoglobulin and mucin domain-containing protein 3 (TIM-3, CD366), V-domain Ig suppressor of T cell activation (VISTA), T cell immunoglobulin and ITIM domain (TIGIT), and Lymphocyte activation gene 3 (LAG-3). We observed differences in the surface expression of ICPs in the analyzed subpopulations of lymphocytes between early pregnancy and RSA, after miscarriage, and in women. We noted diminished expression of PD-1 on T lymphocytes (p = 0.0046), T helper cells (CD3CD4 positive cells, p = 0.0165), T cytotoxic cells (CD3CD8 positive cells, p = 0.0046), T regulatory lymphocytes (CD3CD4CD25CD127 low positive cells, p = 0.0106), and NKT cells (CD3CD56/CD16 positive cells, p = 0.0438), as well as LAG-3 on lymphocytes T (p = 0.0225) T helper, p = 0.0426), T cytotoxic cells (p = 0.0458) and Treg (p = 0.0293), and cells from RSA women. Impaired expression of TIM-3 (p = 0.0226) and VISTA (p = 0.0039) on CD8 cytotoxic T and NK (TIM3 p = 0.0482; VISTA p = 0.0118) cells was shown, with an accompanying increased expression of TIGIT (p = 0.0211) on NKT cells. The changes in the expression of surface immune checkpoints indicate their involvement in the regulation of pregnancy. The data might be utilized to develop specific therapies for RSA women based on the modulation of ICP expression. Full article

The implementation of heat sinks in high-power pulse electronic devices within hypersonic aircraft cabins has been facilitated by the emergence of innovative phase change materials (PCMs) characterized by excellent thermal conductivity and high latent heat. In this study, a representative material, layered porous media filled with paraffin wax, was utilized, and a three-dimensional numerical model based on the enthalpy-porosity approach was employed. A thermal response research was conducted on the Phase Change Heat Exchange Unit with Layered Porous Media (PCHEU-LPM) with different cooling methods. The results indicate that water cooling proved to be suitable for the PCHEU-LPM with a heat flux of 50,000 W/m². Additionally, parametric studies were performed to determine the optimal cooling conditions, considering the inlet temperature and velocity of the cooling flow. The results revealed that the most suitable conditions were strongly influenced by the coolant inlet parameters, along with the position of the PCM interface. Finally, the identification of the parameter combination that minimizes temperature fluctuations was achieved through the Response Surface Analysis method (RSA). Subsequent verification through simulation further reinforced the reliability of the proposed optimal parameters. Full article

Unmanned ground vehicles (UGVs) have gained increased attention in different fields of application; therefore, their optimization requires special attention. Lowering the mass of a UGV is especially important to increase its autonomy, agility, and payload capacity and to reduce dynamic forces. This contribution deals with optimizing a UGV unit prototype that, when connected with similar units, forms a moving electric fence for animal grazing. Together, these units form a robotic system that is intended to solve the critical problem of lack of human capacity in herding and grazing. This approach employs topology optimization (TO) and finite element analysis (FEA) to lower the mass of a UGV unit and validate the design of its structural components. To our knowledge, no optimization of this type of UGV has been reported in the literature. Here, we present the results of a case study in which a set of four load cases served as a basis for the optimization of the UGV frame. Response surface analysis (RSA) was used to identify the worst load cases, while substructuring was used to allow for more detailed meshing of the frame portion that was subjected to TO. Thereby, we demonstrate that the prototype of the UGV unit can be built using standard parts and that TO and FEA can be efficiently used to optimize the load-carrying structure of such a specific vehicle. Full article

Studies on antihypertensive chickpea protein hydrolysates have rarely performed in vivo evaluations, limiting the entry of such hydrolysates into functional food development and clinical trials. Thus, our aim was to optimize the hydrolysis conditions to produce an alcalase-based chickpea hydrolysate with a hypotensive effect in vivo at convenient oral doses. The hydrolysis reaction time, temperature, and alcalase/substrate concentration were optimized using a response surface analysis (RSA). ACE-I inhibition was the response variable. The optimized hydrolysis conditions were time = 0.5 h, temperature = 40 °C, and E/S concentration = 0.254 (U/g). The IC₅₀ of the optimized hydrolysate (OCPH) was 0.358 mg/mL. Five hydrolysates from the RSA worksheet (one of them obtained after 5 min of hydrolysis (CPH15)) had an ACE-I inhibitory potential similar to that of OCPH (p > 0.05). At 50 mg/kg doses, OCPH and CPH15 promoted a clinically relevant hypotensive effect in spontaneously hypertensive rats, up to −47.35 mmHg and −28.95 mmHg, respectively (p < 0.05 vs. negative control). Furthermore, the hypotensive effect was sustained for at least 7 h post-supplementation. Overall, OCPH and CPH15 are promising ingredients for functional food development and as test materials for clinical trials. Full article

Conveying and baling are two important links in the mechanized harvesting of ramie, in the face of ramie cutting and baling harvesting technology research gaps, low stalk conveying rate, high breaking rate and other problems. In this paper, according to the technical requirements of ramie harvesting, we designed a conveying and baling device, the hand-held ramie cutter. First, the key mechanism of the conveying and baling device of the equipment was designed. Then, we analyzed the location of stem clogging and the reasons for the breaking problem during the conveying and baling process. The field harvesting experiments were carried out according to the principles of Box–Behnken experimental design. Taking the machine travelling speed, conveying speed and ramie raking frequency as the test factors and using the Design-Expert V8.0.6.1 to process the data, we established a regression model for each experimental factor on the conveying rate and breaking rate. The order of influence of several factors on the breaking rate is: X₂ > X₁ > X₃; and the effects of the three factors on the conveying rate were X₃ > X₂ > X₁. Through response surface analysis (RSA), the effects of the factors on the indicators were explained, as was the impact of the factors on the indicators. Finally, the parameter optimization was carried out with the delivery rate as the core index. The best combination of motion parameters was obtained as follows: the travelling speed was 0.37 m/s, the chain conveying speed was 1.1 m/s, and the raking frequency was 144 times/min. With the combination of parameters under the field test verification, the results show that compared with the original work quality, the stalk delivery rate increased from 85.2% to 93% (an increase of 7.8%), the stalk breaking rate fell from 31.1% to 20.4% (a decrease of 10.7%). The performance of ramie harvesting and baling was greatly improved, and we achieved relatively satisfactory results. Full article