Clarifying the correlations between hydraulic indicators evaluating the hydraulic performance of free water surface constructed wetlands.

Previous studies have shown a strong linear correlation between the common hydraulic indicators of free water surface constructed wetlands (FWS CWs), which results in the waste of computing resources and confusion in evaluating the hydraulic performance of FWS CWs. There is an urgent need to define a relatively independent and authoritative hydraulic indicator. In this study, based on three years' data, the correlations among five representative hydraulic indicators, that is, short-circuit index (φ10), Morrill dispersion index (MDI), effective volume ratio (e), moment index (MI), and hydraulic efficiency (λe), were analyzed by combining a variety of methods. The results of the correlation analysis and principal component analysis clearly showed the positive correlations among φ10, e, MI, and λe (p < 0.01), and the strong negative correlations between MDI and the remaining four indexes, which were further confirmed by redundancy analysis (RDA). Most importantly, the significant correlations between MI vs e and φ10 vs e were proved through rigorous mathematical reasoning for the first time. Besides, the results of RDA indicated that the studied design parameters, namely, water depth, hydraulic loading rate, plant spacing, aspect ratio, layout of inlet and outlet, and plant species, could generally explain the variation in hydraulic indicators. The layout of inlet and outlet displayed positive effects on hydraulic performance, and the water depth exhibited negative effects. Combining the clarity of physical meaning, convenience of calculation, and universality of reflecting both hydraulic and treatment performances, e was recommended as the most authoritative hydraulic indicator to evaluate hydraulic performance. The clustering results based on e were highly consistent with those based on the comprehensive principal component score. Wetlands with a combination of lower water depth and better layout of inlet and outlet usually have better hydraulic performance. This study successfully revealed the significant correlations among hydraulic indicators and their sources, and recommended a unique hydraulic indicator to authoritatively evaluate the hydraulic performance of FWS CWs.

Design and Mixing Analysis of a Passive Micromixer Based on Curly Baffles.

A novel passive micromixer based on curly baffles is proposed and optimized through the signal-to-noise analysis of various design parameters. The mixing performance of the proposed design was evaluated across a wide Reynolds number range, from 0.1 to 80. Through the analysis, the most influential parameter was identified, and its value was found to be constant regardless of the mixing mechanism. The optimized design, refined using the signal-to-noise analysis, demonstrated a significant enhancement of mixing performance, particularly in the low Reynolds number range (Re< 10). The design set obtained at the diffusion dominance range shows the highest degree of mixing (DOM) in the low Reynolds number range of Re< 10, while the design set optimized for the convection dominance range exhibited the least pressure drop across the entire Reynolds number spectrum (Re< 80). The present design approach proved to be a practical tool for identifying the most influential design parameter and achieving excellent mixing and pressure drop characteristics. The enhancement is mainly due to the curvature of the most influential design parameter.

Calculation method for the static carrying curve of double-row different-diameter ball slewing bearings.

A method for calculating the static carrying curve of a double-row different-diameter ball slewing bearing was proposed. The relationship between the internal maximum rolling element load of each row and the combined external axial load and tilting moment load of the slewing bearing was established using the deformation compatibility and force equilibrium conditions. The rolling element load distribution range parameters of the main and auxiliary raceways of the double-row different-diameter ball slewing bearing were used as input invariables, and the corresponding external load combinations of the axial and tilting moment loads of the slewing bearing were obtained. These external load combinations were plotted in the coordinate system to obtain the static carrying curve of the slewing bearing. The obtained static carrying curve was compared with that calculated using the finite element method for verification. Finally, the influences of detailed design parameters such as the raceway groove radius coefficient, raceway contact angle, and rolling element diameter on the carrying capacity of the double-row different-diameter ball slewing bearing were analyzed based on the carrying curves. As the groove radius coefficient increases from 0.515 to 0.530, or the contact angle increases from 50° to 65°, the carrying capacity of the slewing bearing decreases. As the rolling element diameter increases from 0.90 times the initial diameter to 1.05 times the initial diameter, the carrying capacity of the slewing bearing increases.

Quantitative prediction of the hydraulic performance of free water surface constructed wetlands by integrating numerical simulation and machine learning.

Quantitative prediction of the design parameter-influenced hydraulic performance is significant for optimizing free water surface constructed wetlands (FWS CWs) to reduce point and non-point source pollution and improve land utilization. However, owing to limitations of the test conditions and data scale, a quantitative prediction model of the hydraulic performance under multiple design parameters has not yet been established. In this study, we integrated field test data, mechanism model, statistical regression, and machine learning (ML) to construct such quantitative prediction models. A FWS CW numerical model was established by integrating 13 groups of trace data from field tests. Subsequently, training, test and extension datasets comprising 125 (5^3), 25 (L25(56)) and 16 (L16(44)) data points, respectively, were generated via numerical simulation of multi-level value combination of three quantitative design parameters, namely, water depth, hydraulic loading rate (HLR), and aspect ratio. The short circuit index (φ10), Morrill dispersion index (MDI), hydraulic efficiency (λ) and moment index (MI) were used as representative hydraulic performance indicators. Training set with large samples were analyzed to determine the variation rules of different hydraulic indicators. Based on the control variable method, φ10, λ, and MI grew exponentially with increasing aspect ratio whereas MDI showed a decreasing trend; with increasing water depth, φ10, λ, and MI showed polynomial decreases whereas MDI increased; with increasing HLR, φ10, λ, and MI slowly increased linearly whereas MDI showed the opposite trend. Finally, we constructed models based on multivariate nonlinear regression (MNLR) and ML (random forest (RF), multilayer perceptron (MLP), and support vector regression. The coefficients of determination (R2) of the MNLR and ML models fitting the training and test sets were all greater than 0.9; however, the generalization abilities of different models in the extension set were different. The most robust MLP, MNLR without interaction term, and RF models were recommended as the preferred models to hydraulic performance prediction. The extreme importance of aspect ratio in hydraulic performance was revealed. Thus, gaps in the current understanding of multivariate quantitative prediction of the hydraulic performance of FWS CWs are addressed while providing an avenue for researching FWS CWs in different regions according to local conditions.

Sustainable Packaging Design for Molded Expanded Polystyrene Cushion.

A molded expanded polystyrene (EPS) cushion is a flexible, closed-cell foam that can be molded to fit any packing application and is effective at absorbing shock. However, the packaging waste of EPS cushions causes pollution to landfills and the environment. Despite being known to cause pollution, this sustainable packaging actually has the potential to reduce this environmental pollution because of its reusability. Therefore, the objective of this study is to identify the accurate design parameter that can be emphasized in producing a sustainable design of EPS cushion packaging. An experimental method of drop testing and design simulation analysis was conducted. The effectiveness of the design parameters was also verified. Based on the results, there are four main elements that necessitate careful consideration: rib positioning, EPS cushion thickness, package layout, and packing size. These parameter findings make a significant contribution to sustainable design, where these elements were integrated directly to reduce and reuse packaging material. Thus, it has been concluded that 48 percent of the development cost of the cushion was decreased, 25 percent of mold modification time was significantly saved, and 27 percent of carbon dioxide (CO2) reduction was identified. The findings also aided in the development of productive packaging design, in which these design elements were beneficial to reduce environmental impact. These findings had a significant impact on the manufacturing industry in terms of the economics and time of the molded expanded polystyrene packaging development.

Design and Compressive Fatigue Properties of Irregular Porous Scaffolds for Orthopedics Fabricated Using Selective Laser Melting.

An irregular porous structure plays a major role in bone tissue engineering, and it is more suitable for bone tissue growth than a regular porous structure. The response surface method was used to establish a relationship between the average pore size and the design parameters. The technology of selective laser melting was utilized to fabricate the porous Ti-6Al-4V scaffolds with an irregularity of (0.4) and porosities of (70, 80, and 90%) designed using the Voronoi-tessellation method. Compression tests of porous scaffolds showed an elastic modulus range of 0.84-1.97 GPa and an ultimate strength ranging within 21.0-99.1 MPa. The elastic modulus was mainly influenced by the porosity and heat-treatment process. Furthermore, the fatigue test results suggested that the number of cycles (9 × 104 to 1.8 × 106) was greatly influenced by the porosity and heat-treatment process. The heat treatment of annealing greatly improved the fatigue performance of porous scaffolds. The irregular porous scaffolds with lower porosity and after full annealing exhibited the best fatigue behavior.

Response of solute transport model parameters to the combination of multiple design parameters and their quantitative expression with hydraulic indicators of FWS-constructed wetlands.

Solute transport models and hydraulic indicators are commonly used to assess the flow pattern of free water surface-constructed wetlands (FWS CWs). However, the relationship between solute transport models and hydraulic performance remains poorly understood. The hybrid model comprised of plug flow with dispersion and continuous stirred tank reactors (PFD + CSTRs) was applied in this study. The variation rules of model parameters, namely the flow ratio of the mixed zone f, volume ratio of the mixed zone z, dispersion number D, and number of mixed tanks N, were obtained by fitting of the normalized tracer data of orthogonal tests. The coefficients of determination (R2) exceeded 0.7 and the correlation coefficient (r) surpassed 0.8. The results demonstrated satisfactory hydraulic performance and purification effect, with high hydraulic and water quality indicators. Water depth was the principal design parameter negatively affecting f and z, whereas the layout of in- and outlet positively influenced D and N. The R2 of the model parameters f, z, and D on most hydraulic indicators were above 0.5. Significantly positive correlations existed between the model parameters f, z, and D and the hydraulic indicators including the short-circuit index φ10, effective volume ratio e, and moment index MI. The quantitative links between model parameters and hydraulic indicators were established. Based on the significant correlations between design parameters, hydraulic indicators, and model parameters, it would be more convenient to evaluate the hydraulic performance of FWS CWs corresponding to specific design parameters. Graphical abstract.

Designing an electronic blood-borne virus risk alert to improve uptake of testing.

The primary aim of the current study was to test the effect of the presentation design of a test alert system on healthcare workers' (HCWs') decision-making regarding blood-borne virus (BBV) testing. The secondary aim was to determine HCWs' acceptance of the system. An online survey used a within-subjects research design with four design factors as independent variables. The dependent variable was clinical decision. Ten realistic descriptions of hypothetical patients were presented to participants who were asked to decide whether to request BBV testing. The effect of a pre-set course of action to request BBV testing was significant when additional information (cost-effectiveness, date of last BBV test or risk assessment) was not presented, with a 16% increase from 30 to 46% accept decisions. When risk assessment information was presented without a pre-set course of action, the effects of cost-effectiveness (27% increase) and last test date (23% decrease) were significant. The main reason for declining to test was insufficient risk. HCWs' acceptance of the test alert system was high and resistance was low. We make recommendations from the results for the design of a subsequent real-world trial of the test alert system.

Performance of Different Urban Design Parameters in Improving Outdoor Thermal Comfort and Health in a Pedestrianized Zone.

Global climate change and urban heat islands have generated heat stress in summer, which does harm to people's health. The outdoor public commercial pedestrianized zone has an important role in people's daily lives, and the utilization of this space is evaluated by their outdoor thermal comfort and health. Using microclimatic monitoring and numerical simulation in a commercial pedestrianized zone in Tai Zhou, China, this study investigates people's outdoor thermal comfort in extreme summer heat. The final results provide a comprehensive system for assessing how to improve outdoor human thermal health. Under the guidance of this system, local managers can select the most effective strategy to improve the outdoor thermal environment.

Finite element analysis of archwire parameters and activation forces on the M/F ratio of vertical, L- and T-loops.

BACKGROUND: The ability of a loop to generate a certain moment/force ratio (M/F ratio) can achieve the desired tooth movement in orthodontics. The present study aimed to investigate the effects of elastic modulus, cross-sectional dimensions, loop configuration geometry dimensions, and activation force on the generated M/F ratio of vertical, L- and T-loops. METHODS: A total of 120 three-dimensional loop models were constructed with the Solidworks 2017 software and used for simulating loop activation with the Abaqus 6.14 software. Six vertical loop variations, 9 L-loop variations, and 9 T-loop variations were evaluated. In each group, only one parameter was variable [loop height, ring radius, leg length, leg step distance, legs distance, upper length, different archwire materials (elastic modulus), cross-sectional dimension, and activation force]. RESULTS: The simulation results of the displacement and von Mises stress of each loop were investigated. The maximum displacement in the height direction was recorded to calculate the M/F ratio. The quantitative change trends in the generated M/F ratio of the loops with respect to various variables were established. CONCLUSIONS: Increasing the loop height can increase the M/F ratio of the loop. This increasing trend is, especially, much more significant in T-loops compared with vertical loops and L-loops. In vertical loops, increasing the ring radius is much more effective than increasing the loop height to increase the M/F ratio of the loop. Compared with SS, TMA archwire loops can generate a higher M/F ratio due to its lower elastic modulus. Loops with a small cross-sectional area and high activation force can generate a high M/F ratio. The introduction of a leg step to loops does not increase the M/F ratio of loops.

Development of Mixed Flow Fans with Bio-Inspired Grooves.

Mixed flow fan is a kind of widely used turbomachine, which has faced problems of further performance improvement in traditional design methods in recent decades. Inspired by the microgrooves such as riblets and denticles on bird feathers and shark skins, we here propose biomimetic designs of various blades with the bio-inspired grooves, aiming at the improvement of the aeroacoustic performance. Based on a systematic study with computational fluid dynamic analyses, we found that these designs had the potential in noise suppression even with macroscopic grooves. Our best design can suppress turbulence kinetic energy by approximately 38% at the blade leading edge with aerodynamic efficiency loss of only 0.3 percentage points. This improvement is achieved by passive flow control. The vortical structures are changed in a favorable way at the leading edge due to the grooves. We believe that these biomimetic designs could provide a promising future of enhancing the performance of mixed flow fans by making grooves of ideal flow passages on the suction faces of blades in accord with the theory of pump design.

Improved test to determine design parameters for optimization of free surface flow constructed wetlands.

Orthogonal tests were performed to assess the effect of design parameters on hydraulic and treatment performances of constructed wetlands. The results showed that water depth, layout of in- and outlet, flow rate, and aspect ratio mainly affected hydraulic performance, and water depth, plant spacing, and layout of in- and outlet mainly affected treatment performance. Optimal integrated performance was achieved with combination of 20-30 cm water depth, five evenly distributed inlets and one middle outlet, a flow rate of 0.4-0.55 m3/h, 20-cm plant spacing, a 1.125:1 aspect ratio, and planted with Scripus tabernaemontani. The average treatment performances of 27.2%, 16.3%, and 30.7% removal rates were received for total nitrogen, total phosphorus, and total suspended solid, respectively. The design parameters that significantly influenced hydraulic performance did not significantly influence treatment performance. Various hydraulic and purification indicators displayed extremely significant correlations. There was a significant correlation between hydraulic performance and mass removal capacity.

Finite element model predicts the biomechanical performance of cervical disc replacement and fusion hybrid surgery with various geometry of ball-and-socket artificial disc.

PURPOSE: Few finite element studies have investigated changes in cervical biomechanics with various prosthesis design parameters using hybrid surgery (HS), and none have investigated those combined different HS strategies. The aim of our study was to investigate the effect of ball-and-socket prosthesis geometry on the biomechanical performance of the cervical spine combined with two HS constructs. METHODS: Two HS strategies were conducted: (1) ACDF at C4-C5 and anterior cervical disc replacement (ACDR) at C5-C6 (ACDF/ACDR), and (2) ACDR/ACDF. Three different prostheses were used for each HS strategy: prosthesis with the core located at the center of the inferior endplate with a radius of 5 mm (BS-5) or 6 mm (BS-6), or with a 5 mm radius core located 1 mm posterior to the center of the inferior endplate (PBS-5). Flexion and extension motions were simulated under displacement control. RESULTS: The flexion motions in supra- and infra-adjacent levels increased in all cases. The corresponding extension motions increased with all prostheses in ACDR/ACDF group. The stiffness in flexion and extension increased with all HS models, except for the extension stiffness with ACDF/ACDR. The facet stresses between the index and infra-adjacent level in ACDR/ACDF were significantly greater than those in the intact model . The stresses on the BS-5 UHMWPE core were greater than the yield stress. CONCLUSION: The core radii and position did not significantly affect the moments, ROM, and facet stress in extension. However, the moments and ROM in flexion were easily affected by the position. The results implied that the large core radii and posterior core position in ACDR designs may reduce the risk of subsidence and wear in the long term as they showed relative low stress . The ACDF/ACDR surgery at C4-C6 level may be an optimal treatment for avoiding accelerating the degeneration of adjacent segments.

Test study of the optimal design for hydraulic performance and treatment performance of free water surface flow constructed wetland.

Orthogonal tests with mixed levels of design parameters of a free water surface flow constructed wetland were performed to assess their effect on hydraulic and treatment performance, and discover the relationship between the design parameters and the two performances. The results showed that water depth, plant spacing, and layout of in- and outlet mainly affected the two performances. Under 40cm depth, central pass of in- and outlet, 1.8m3/h flow rate, 20cm plant spacing, 2:1 aspect ratio, and Scripus tabernaemontani as the plant species, treatment performance of 5.3% TN, 6.1% TP and 15.6% TSS removal efficiencies and a high hydraulic performance of 0.854e, 0.602MI were achieved. There was no significant correlation between the design parameters and the two performances. The relationship among various hydraulic indicators and that among the purification indicators displayed extremely significant correlation. However, there was no significant correlation between hydraulic and treatment performance.