Mixing Index Research Articles

Feed Resources for Livestock and Improved Forage Production Status in Enor Woreda, Gurage Zone of Ethiopia

This study was conducted with the objective of assessing feed resources for livestock and improved forage production status in Enor woreda. Three kebeles were selected purposively based on livestock potential, 90 forage producer farmers, 30 from each kebele were selected using systematic random sampling from forage participant lists. SPSS (version 20) were used for analyzing the data. Mean land holdings of the area were 2.98 (SD=0.2), 2.86 (SD=0.19) and 2.93 (SD=0.21) in enset, cereal and mixed based farming system, respectively. Cereal dominate system has higher TLU than other two farming system. Feed shortage was the primary challenge in enset-based (Index=0.26), cereal-based (Index=0.32) and mixed (Index=0.32) farming system followed by water shortage problem in both enset and cerealbased system. Natural pasture (28%), crop residues (straw) (23%), hay (17%), improved forages (13%) enset (12%) and by-products from industries (7%) were observed to be the major feed resources in the area. In all the three agro-ecologies, Desho grass (Pennisetum pedicellatum) and Elephant grass (Pennisetum purpureum) were the dominant forage species, whereas Sesbania (Sesbaina sesban) was the dominant in cereal-based system adopted in the area.

Improvement of mixing performance in laminar micromixers utilizing vortex-induced vibration of two circular cylinders

Micromixers have found extensive applications in various fields such as engineering, biomedicine, medical and chemistry. The utilization of vortex-induced vibration (VIV) of bluff bodies can greatly enhance fluid mixing in micromixers. This study focuses on numerically investigating the interaction between vortex-induced vibration of two cylinders, labeled Cyl-S (stationary cylinder) and Cyl-V (vibrating cylinder), and the mixing performance of micromixers. Specifically, the study examines the effects of spacing ratio (S/D) and vibration system configurations (Cyls-S+S, Cyls-S+V, and Cyls-V+V) on vibration response, near-wake structure, mixing concentration, and mixing index. The results indicate that the spacing ratio directly influences the vibration response of the cylinders, thereby significantly impacting the mixing performance. For the Cyls-V+V configuration, the downstream cylinder exhibits a considerably higher vibration amplitude compared to the upstream cylinder. Increasing the S/D ratio substantially improves the mixing effect in the Cyls-S+S configuration. For the Cyls-S+V and Cyls-V+V configurations, the enhancement of mixing due to VIV is particularly noticeable when S/D ratios of 2 and 3 are employed. The mixing index for Cyls-V+V is higher than that for Cyls-S+V within the range of 3 ≤ U⁎ ≤ 5 (where U* represents the reduced velocity). At a reduced velocity of U⁎ = 4 for Cyls-V+V, the optimal mixing indexs are found to be 0.77 (S/D = 2), 0.76 (S/D = 3), 0.78 (S/D = 4), and 0.77 (S/D = 5), respectively. However, when U⁎ = 6–10, the mixing index decreases due to the vibration of the cylinder is suppressed. Additionally, the Cyls-V+V configuration exhibits a significantly higher pressure drop within the flow channel compared to the Cyls-S+V configuration.

A novel micromixer based on coastal fractal for manufacturing controllable size liposome

The traditional lipid preparation methods are complex, time-consuming, and consume a large amount of reagents, increasing costs and difficulties. Although microfluidic technology is considered a promising solution, achieving controllable liposome production with a simple and inexpensive microfluidic mixing device remains an important problem. This paper presents a wall-type micro-mixer based on coastal zone fractals. Four parameters related to the geometric shape of the coastline fractal in the microchannel are used as design variables, and the mixing index is the objective function. Single-objective optimization numerical analysis of the primary wall-type fractal baffle micromixer under four Reynolds numbers conditions yields the optimal structural configuration. Visualization experiments verify the correctness and accuracy of the numerical simulation, and the optimized mixer is used to produce liposomes. The results show that the micro-mixer with the optimal double-sidewall cross arrangement enhances chaotic convection and improves mixing efficiency. At Re = 0.1 and Re = 100, the mixing efficiency reaches 99%, 50.44% higher than the reference design. By changing the relative flow rates of lipid and aqueous solutions, microfluidic blank liposomes with a particle size of 165.12 ± 11.6 nm and a polydispersity index of 0.35± are obtained. This wall-type fractal micro-mixer has broad application prospects due to its high mixing efficiency.

Investigation of Cross‐Sectional Characteristics of Internal Meshing Screw Mixing Flow Field for Dough Paste

ABSTRACTThe internal meshing screw mixer, driven by extensional rheology, demonstrates excellent mixing efficiency for high‐viscosity materials while minimizing fiber damage. This study developed a computational model for the mixing process of high‐viscosity fluids based on the motion equations of the internal meshing screw. The model was validated through experiments involving the mixing of corn syrup, flour and water. The results reveal the flow field's cross‐sectional streamlines and confirm the presence of chaotic mixing states at the system interface through horseshoe mapping and the existence of hyperbolic points. By comparing the extensional and shear rates, as well as analyzing the distribution of mixing indices, this paper establishes that the primary mixing mechanism within the cross‐section is extensional force, highlighting the role of the internal meshing screw as a mixer dominated by extensional flow fields. We investigate the variations in fluid velocity, velocity uniformity index, extensional rate, shear rate, and mixing index over time under different conditions of eccentricity, rotor radius, and rotational speed. The findings indicate that while eccentricity has a limited impact on average velocity, it significantly enhances velocity disturbances and increases the ratio of extensional effects within the fluid domain. In contrast, rotor radius and speed lead to a linear increase in average velocity but have little effect on velocity disturbances and the extensional effects in the fluid domain. This study provides valuable insights into how various cross‐sectional parameters influence the flow field of the internal meshing screw mixing process, offering crucial support for its application in mixing high‐viscosity non‐Newtonian fluids within the food industry.

Commercial inpatient hospital price growth driven by system affiliation and nonprofit-status hospitals.

As policymakers continue to grapple with rising health care costs and prices, understanding trends and variations in inpatient prices among hospital characteristics is an important benchmark to allow policymakers to craft targeted policies. In this study, we provide descriptive trends on variation in inpatient prices paid by commercial health plans stratified by hospital characteristics using data from Health Care Cost Institute's employer-sponsored insured claims data. Our analyses found evidence of considerable variation among inpatient price levels and growth among system affiliation and profitability. Prices among system-affiliated hospitals grew from $14 281.74 in 2012 to $20 731.95 in 2021, corresponding to a 45.2% increase during this period. On the other hand, prices among independent hospitals grew more slowly, from $13 460.50 in 2012 to $18 196.90 in 2021, corresponding to a 35.2% increase. We did not observe a similar trend in growth rates among case mix index by hospital characteristics, implying that differential inpatient price growth is not driven by changes in case mix by hospital characteristics. Heterogeneity in hospital prices and price growth by type of hospital suggests that public and private policymakers aiming to rein in health spending should consider policies that address this variation.

Digital image analysis of gas bypassing and mixing in gas‐fluidized bed: Effect of particle shape

AbstractThe study investigates effect of particle shape on gas bypassing and mixing of gas‐fluidized Geldart A particles. A shallow fluidized bed (FB), configured at benchscale, was used with digital image analysis (DIA) for the investigation. The extent of scatter of tracer particles throughout the bed was assessed from DIA images of defluidized powder. A novel method employing Jupyter notebook software, was used to directly determine Mixing Index from digital images. Remarkably, platelet‐shaped China clay powder displayed the best mixing characteristics (Mixing Index: 0.79) with no significant bypassing. Angular shaped Quartz displayed moderate mixing (Mixing Index: 0.67), but high bypassing (Bypassing Index: 0.75). Contrary to conventional assumptions, spherical‐shaped diatomite exhibited poor mixing (Mixing Index: 0.61) with the highest bypassing (Bypassing Index: 0.82). Platelet particles performed well even with fines removal. Most likely, particle shape significantly influenced the number of available particle contact points, tracer migration, and traceronparticle binding.

Analysis of the Dispersive and Distributive Mixing Effect of Screw Elements on the Co-Rotating Twin-Screw Extruder with Particle Tracking.

Compounding is an important step in processing base polymers and is used to incorporate various additives into a polymer. For this purpose, different screw elements are used for dispersive and distributive mixing on a co-rotating twin-screw extruder. Optimising the screw configuration requires precise knowledge of the screw elements' mixing properties, which have not been thoroughly investigated. This study analyses the mixing behaviour of individual screw elements regarding dispersive and distributive mixing using 3D CFD flow simulations with subsequent particle tracking. For distributive mixing, the particle distribution behind the screw elements in the XY plane is analysed and the mixing index MQ, which relates the standard deviation and the mean value of the triangular areas between the particles, is calculated. For dispersive mixing, the maximum shear stress on the particle path and the integral of the shear stress over the residence time of each individual particle are determined. The results show that screw element geometry and rotation speed have a significant influence on dispersive and distributive mixing. In addition, better dispersive mixing is achievable with highly viscous materials. These findings enable the optimisation of the mixing zone of a co-rotating twin-screw extruder for the efficient mixing of mineral fillers.

Operational efficiency effect on nursing workload of tertiary hospital wards in China: A prospective observational study.

To investigate the effect of ward operational efficiency on nursing workload and identify the factors that influence nursing workload. It remains unclear how and to what extent ward operational efficiency can influence nursing workload. A prospective observational study was conducted from July 1, 2022 to June 30, 2023, in one tertiary general hospital in China. Purposive and convenience sampling was used, and 266 470 patients from 66 wards and 52 nurses from 13 wards were recruited. The relationships between operational efficiency and nursing workload and the predictors of nursing workload were analyzed. The STROBE guidelines were followed. The operational characteristics vary by the type of wards. Nursing workloads were positively correlated with case mix index (CMI), rate of level 4 surgery, the number of patients transferred in and out, the number of deaths, total bed days, and the number of emergency admissions and critical illnesses (γs: 0.35-0.56, p<0.05). And the CMI, rate of level 4 surgery, average bed occupancy rate, number of critically ill patients, and total bed days were the predictors of nursing workload (R2=57.3%, p<0.05). This study is the first to discuss the relationship between operational efficiency and nursing workload on the ward level and offers valuable insights into the nursing workload. The operational efficiency of wards affects the nursing workload and needs to be considered both in the measurement of nursing activities and in the sizing of the nursing staff. The study findings provide a full understanding of the relationship between ward operation and nurse staffing, which is helpful for nursing managers to formulate scientific nurse staffing policies.

Indices of vector fields for mixed functions

A mixed function is a real analytic map f:Cn→C\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$f:\\mathbb {C}^n\\rightarrow \\mathbb {C}$$\\end{document} in the complex variables z1,⋯,zn\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$z_1,\\dots ,z_n$$\\end{document} and their conjugates z¯1,⋯,z¯n\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\bar{z}_1,\\dots ,\\bar{z}_n$$\\end{document}. In this article, we define an integer valued index for vector fields v with isolated singularity at 0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ extbf{0}$$\\end{document} on real analytic varieties Vf:=f-1(0)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$V_f:=f^{-1}(0)$$\\end{document} defined by mixed functions f with isolated critical point at 0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ extbf{0}$$\\end{document}. We call this index the mixed GSV index and it generalizes the classical GSV index defined by Gomez-Mont, Seade and Verjovsky in (Math Ann 291(4):737–751, 1991), i.e., if the function f is holomorphic, then the mixed GSV index coincides with the GSV index. Furthermore, the mixed GSV index is a lifting to Z\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\mathbb {Z}$$\\end{document} of the Z2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\mathbb {Z}_2$$\\end{document}-valued real GSV index defined by Aguilar, Seade and Verjovsky in Aguilar et al. (J Reine Angew Math 504:159–176, 1998). As applications, we prove that the mixed GSV index is equal to the Poincaré–Hopf index of v on a Milnor fiber. If f also satisfies the strong Milnor condition, i. e., for every ϵ>0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\epsilon >0$$\\end{document} (small enough), the map f‖f‖:Sϵ\\Lf→S1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\frac{f}{\\Vert f\\Vert }:\\mathbb {S}_\\epsilon {\\setminus } L_f \\rightarrow \\mathbb {S}^1$$\\end{document} is a fiber bundle, we prove that the mixed GSV index is equal to the curvatura integra of f defined by Cisneros-Molina, Grulha and Seade in (Int J Math 25(7): 1450069, 2014) based on the curvatura integra defined by Kervaire in (Courbure integrale generalisee et homotopie., Mathematische Annalen, pp. 219–252, 1956).

Numerical study of two equal-sized miscible drops undergoing head-on collision

The numerical analysis focuses on investigating head-on collisions between two miscible drops composed of distinct fluids, specifically ethanol and water. The simulations are performed using a coupled level set and volume of fluid approach with different Weber numbers to study the effect of drop inertia. The code is validated against experimental and numerical results from earlier investigations. Additionally, a comparative study involving both water drops and ethanol–water drops is conducted to explore the impact of varying surface tension ratios on collision outcomes. Results show that when miscible drops collide, the merged liquid drop exhibits asymmetric behavior, such as an asymmetric combined drop shape in cases of permanent coalescence or an asymmetric end droplet breakup in cases of reflexive separation. The collision outcome undergoes significant variation as the Weber number changes. At lower Weber numbers, permanent coalescence is observed, while at medium Weber numbers, reflexive separation occurs without the formation of a secondary drop. For medium to large Weber numbers, reflexive separation with the generation of one secondary drop becomes prominent, and in the case of very large Weber numbers, multiple satellite drops form. The maximum vertical elongation of the merged drop and corresponding surface energy increase as the surface tension ratio rises, irrespective of the Weber number. However, for a fixed surface tension ratio, the maximum vertical elongation and associated surface energy vary with an increase in the Weber number. The findings also shed light on the enhanced internal mixing arising from the mismatched surface tension of the colliding drops as the Weber number increases. Furthermore, the study explores the effect of drop inertia on various aspects, including asymmetric collision behavior, energy budget, and mixing index.

Numerical and experimental investigation of Tesla micromixers with different three-dimensional herringbone structures

Laminar flow within channels at the micro- or nano-scale of the microfluidic device restricts the rapid mixing of different fluids, leading to reduced reaction velocity. In this study, different three-dimensional herringbone structures were designed to the Tesla micromixers to enhance transverse flow and vortex flow in the channels. Computational fluid dynamics (CFD) simulation results indicated that the sunken herringbone structure provided the most significant enhancement in mixing. The raised herringbone structure exhibited the best energy performance. When Reynolds number (Re) exceeded 60, the mixing indexes (MI) of the Tesla micromixers were over 90%. The improvement in mixing efficiency by both herringbone structures compensated for the weak mixing performance of the Tesla structure at lower Reynolds numbers (Re=0.2-30). Additionally, the mixing experimental results verified the accuracy of the simulation results. This study could provide guidance for improving the mixing performance of micromixers over a wide range of Reynolds numbers (Re=0-100).

Advancing aquifer vulnerability mapping through integrated deep learning approaches

Groundwater vulnerability maps are crucial for safeguarding groundwater quality. A research gap exists in using advanced data fusion techniques to identify areas subject to seawater intrusion. To address this gap, this research enhances the GALDIT method and applies diverse deep learning models, combined with machine learning techniques, to improve the precision of aquifer vulnerability mapping. The new GALDITMW model incorporates the seawater mixing index and the parameters related to the production well density and aquifer porous medium. For the first time, supervised and unsupervised deep learning models, such as deep neural networks, deep belief networks, deep stacked autoencoders, and convolutional neural networks, are used for vulnerability mapping. In the second stage, the results of various machine learning models are fused to improve performance. The models' effectiveness is evaluated using a vulnerability index based on total dissolved solids (TDS) in an aquifer hydraulically connected with Salt Lake in central Iran, which faces groundwater depletion and salinization. The evaluation of the models based on performance metrics and the confusion matrix demonstrates that initial deep-learning models perform well. Significant improvements were observed in the second stage involving machine learning models, confirming their strong correlation (R2 > 0.985) with observed chloride values. The GPR model achieved an F1 score of 86.92%, an NSE of 0.911, and an RMSE reduction of 0.026 mg/L compared to the first-stage models. The proposed method offers a novel and accurate method for identifying vulnerable areas and provides helpful information for groundwater resource management.

Configuration optimization of a biomass chemical looping gasification (CLG) system combined with CO2 absorption

Biomass chemical looping gasification (CLG) combined with CO2 absorption in a dual circulating fluidized bed (DCFB) has emerged as an advanced technology for clean and efficient biomass utilization, yet the reactor design for achieving higher gasification performance and the in-depth understanding of physical-thermal-chemical characteristics is still lacking. This study presents an optimized design aimed at enhancing hydrogen production and carbon reduction in the biomass CLG process with a DCFB reactor by employing the multiphase particle-in-cell (MP-PIC) method integrated with thermochemical sub-models. The proposed reactor is comprehensively compared with the original reactor from the experimental setup in terms of particle mixing, heat transfer, and gasification behaviors. The results indicate that compared to the original setups, the proposed CLG system demonstrates: (i) an improved gas-solid mixing, as evidenced by the particle mixing index rising from 0.23 to 0.34; (ii) an enhanced particle heat transfer coefficient, which boosts heat and mass transfer process; (iii) a 10.11 % increase in H2 concentration alongside a 23.71 % decrease in CO2 concentration; (iv) a particle distribution characterized by higher concentration at the bottom and lower concentration at the top, along with intensified particle back-mixing. The pressure drop inside the combustor is higher than that in the gasifier. A smaller absorbent mean particle diameter and lower-positioned biomass feeding port contribute to the improvement of the CLG performance.

Improvement of mixing efficiency in twisted micromixers: The impact of cross-sectional shape and eccentricity ratio

Microfluidic mixers with twisted geometries show promise for high mixing efficiency, especially at elevated flow rates. However, there is a lack of understanding regarding the optimal geometrical parameters to enhance mixing across various Reynolds numbers. This study aimed to explore the influence of pitch number, cross-section geometry, and eccentricity ratio on the performance of the twisted micromixer. The flow field in these micromixers was solved numerically and the mixing index and pressure drop were calculated for Reynolds numbers of 1 to 400. Twisted micromixers with rectangular cross-sections and aspect ratios of 0.5 and 2 outperformed those with square cross-sections by up to 34% in mixing efficiency, exceeding 90% efficiency for Reynolds numbers from 1 to 400. Moreover, the eccentricity ratio (ER) was studied for the first time in twisted micromixers in this study and demonstrated a critical role in improving the mixing performance. For low to intermediate Reynolds numbers, the highest ER of 0.75 showed the best performance, while for high Reynolds numbers, an ER of 0.5 was optimal. These insights offer valuable direction for designing high-performance micromixers for advanced microfluidic systems.

Analyzing Homogeneity of Highly Viscous Polymer Suspensions in Change Can Mixers.

The mixing of highly viscous non-Newtonian suspensions is a critical process in various industrial applications. This computational fluid dynamics (CFD) study presents an in-depth analysis of non-isothermal mixing performance in change can mixers. The aim of the study was to identify parameters that significantly influence both distributive and dispersive mixing in these mixers, which are essential for optimizing industrial mixing processes. The study employed a numerical design of experiments (DOE) approach to identify the parameters that most significantly influence both distributive and dispersive mixing, as measured by the Kramer mixing index (MKramer) and the Ica Manas-Zloczower mixing index λMZ¯. The investigated parameters included mixing time, number of arms, arm size ratio, revolutions per minute (RPM), z-axis rotation, z-axis movement, and initial and mixing temperatures. The methodology involved employing the bootstrap forest algorithm for predicting the mixing indices, achieving an R2 of 0.949 for MKramer and an R2 of 0.836 for λMZ¯. The results indicate that the z-axis rotation has the greatest impact on both distributive and dispersive mixing. An increased number of arms negatively impacted λMZ, but had a small positive effect on MKramer. Surprisingly, in this study, neither the initial temperature of the material nor the mixing temperature significantly impacted the mixing performance. These findings highlight the relative importance of operational parameters over traditional temperature factors and provide a new perspective on mixing science.

Comparative experimental and numerical study of mixing efficiency in 3D-printed microfluidic droplet generators: T junction, cross junction, and asymmetric junctions with varying angles

In droplet-based microfluidics, rapid mixing during droplet formation enhances reaction uniformity, eliminating the need for micromixers. In this research, we conducted a comprehensive study by first employing a series of two-dimensional (2D) numerical simulations, followed by experimental investigations using 3D-printed microfluidic chips. We compared the mixing efficiency, droplet diameter, and droplet eccentricity of three different types of droplet generators: T junction, cross junction, and asymmetric droplet generators with various angles. Regarding mixing efficiency, we observed that the asymmetric droplet generators outperformed the cross junction by 30 % but fell slightly short of the mixing efficiency achieved by the T junction (1 %). Additionally, while the mixing index in the asymmetric generators closely matched that of the T junction, these asymmetric generators produced smaller droplets by 72 %. Increasing the angle in asymmetric droplet generators resulted in enhanced mixing efficiencies and an increase in droplet diameters. The asymmetric junction with a 30° angle could achieve a mixing efficiency of up to 80 %. Additionally, an analysis of the dispersed phase flow rate revealed that higher flow rates lead to larger droplet sizes and reduced mixing efficiencies. The asymmetric droplet generators improve mixing efficiency facilitating rapid reagent mixing, all while maintaining a small droplet diameter.

CFD–DEM modeling of particle segregation behavior in a simulated flash smelting furnace

Particle behavior plays a crucial role in flash smelting furnaces, but limited understanding is hindering further development of this modern pyrometallurgical process. This study presents a two-way coupled CFD–DEM approach to investigate particle distribution, collision, and segregation behaviors within a furnace. The simulation results are validated against experimental data, demonstrating good agreement. The effects of the particle mass–flow rate and size distribution are then analyzed. The results indicate that small particles are carried by airflows to the center of the particle-dense region, whereas large particles remain at the outer part, worsening segregation. Increasing the mass–flow rate significantly increases the particle number density and number of particle collisions but barely influences size-induced segregation. In contrast, enlarging the size of fed particles reduces particle number density and broadens dense distribution within a safe range. This ensures the necessary space and high mixing index of the particles, which benefits high-rate smelting processes.

Length of stay and cost of care differences between postoperative patients who board in PACU and those that proceed directly to inpatient bed

BackgroundBottlenecks in PACU throughput are frequently encountered challenges that OR managers must face. This study seeks to examine the impact of extended PACU stay (e.g. boarding) on both total hospital length of stay and overall cost of care. MethodsA total of 4,740 patients were studied having same-day admit surgeries for seven procedure types including: arthroplasty total knee, arthroplasty total hip, fusion spine transforaminal interbody lumbar, revision arthroplasty total knee, revision arthroplasty total hip, posterior cervical fusion, and anterior cervical fusion. 4,471 were identified as non-PACU boarders and 269 as PACU boarders (>6 h in PACU). Included in the analysis were demographics, date of admission, surgical procedure, PACU and hospital length of stay (HLOS), hospital direct costs, case mix index (CMI), and ASA status. ResultsThe median (IQR) PACU times in minutes were 57.00 (80) and 488.00 (453.50) minutes for PACU non-boarders and boarders (p < 0.001). HLOS was significantly (p < 0.001) more elevated in PACU Boarders compared to PACU Non-boarders: median (IQR) 2.00 (2.00) and 2.00 (3.00), (mean HLOS 3.16±2.83 vs 2.60±2.71 days). Median direct costs were ≈14.36% higher (p = 0.008) for the PACU boarders compared to Non-boarders. Direct costs were also not significantly different when using a 4-hour criteria for PACU boarders (14.39% higher median direct costs, p = 0.004). ConclusionsPACU boarding (>4 h) is associated with a statistically significant increased length of stay as well as direct costs compared with non-boarders across a variety of elective orthopedic and spine procedures. Thus, when frequent PACU boarding occurs, OR managers should consider the potential impact to patient care and hospital margins.

Data-driven approach for design and optimization of rotor–stator mixers for miscible fluids with different viscosities

Rotor–stator mixers (RSMs) are essential equipment used in the food, pharmaceutical, and cosmetic industries. The performance of RSMs is conventionally analyzed using three approaches based on empirical correlations and experimental and numerical analyses. This paper introduces a new approach based on a multifidelity data-driven framework for designing and optimizing RSMs that systematically combines elements of experimental and high-resolution computational fluid dynamics (CFD) models to train a machine learning model to predict RSM performance. It was subsequently coupled to an optimization solver based on a genetic algorithm. The developed framework was applied to a small-scale RSM with variable rotor blade radius, rotor speed, stator mesh width, and mass flow rate that is operated to mix two miscible fluids with different viscosities. The RSM was optimized at two regimes of low and high viscosities to achieve the best performance in terms of shaft power and mixing indices. The results demonstrate the successful application of the developed frameworks. The optimization of the mixing of high-viscosity fluids yielded a higher improvement than that for low-viscosity fluids. A decrease in shaft power of approximately 50% was obtained for the high-viscosity fluids, whereas the mixing indices increased up to 20% by the optimization of the geometrical input design parameters. The proposed framework can be advantageous for designers and operators at the industrial scale.

Comparison of Externally Transferred and Self-Recruited Patients with Hip and Knee Revision Arthroplasty at a Certified Maximum-Care Arthroplasty Center (ACmax).

According to the guidelines of the EndoCert initiative, certified maximum-care arthroplasty centers (ACmax) are obliged to admit patients from certified arthroplasty centers (AC) if these patients need to be transferred to the more specialized ACmax due to difficult replacement and revision procedures as well as after complications in primary care that are beyond the expertise of the smaller centers. This study investigated whether the cohort of transferred patients differed from the patients directly recruited at the ACmax for factors such as severity of diagnosis, comorbidities or outcome. The aim was to determine whether transferred patients increased the resource requirements for the ACmax. A total of 136 patients were included in the retrospective study and analyzed in terms of case severity, length of hospital stays (LOS), Diagnosis-Related Group charges, readmission rate and concomitant diseases. All patients were followed for up to 12 months after the initial hospital stay. There were significant differences between the groups of transferred and self-recruited patients. For example, transferred patients had a higher Patient Clinical Complexity Level (PCCL). Similarly, the increased Case Mix Index (CMI) of transferred patients indicated more intensive care during the inpatient stay. The higher values for the comorbidity indices also supported these results. This had an impact on the LOS and overall costs, too. The differences between the groups were also reflected by adverse events during the one-year follow-up. The higher percentage of patients with septic revisions, whose treatment is especially demanding, among transferred patients aggravated the differences even further. Thus, transferred patients were associated with increased resource requirements for the ACmax. While it serves patients' safety to transfer them to an ACmax with specialized expertise and greater structural quality, the care of transferred patients ties up considerable resources at the ACmax that might only be insufficiently reimbursed by the generalized tariffs.