Equivalent Size Research Articles

Effects of learning analytics-based feedback on students’ self-regulated learning and academic achievement in a blended EFL course

This study explores the impact of learning analytics (LA)-based feedback on students' self-regulated learning (SRL) and academic achievement in a blended English-as-a-foreign-language (EFL) course. Employing a quasi-experimental research design, this study utilized propensity score matching (PSM) to form a treatment group (N = 160) from the 2023 undergraduate student cohort, receiving LA-based feedback, and matched it with a comparison group of equivalent size from the 2021 and 2022 cohorts without such feedback. Guided by Winne and Hadwin's COPES model (1998), SRL was operationalized at a coarse level with students' online log data and course assessment scores representing their SRL operations and products of SRL in the course, respectively. Results of mixed ANOVAs and chi-square tests of independence showed that the LA-based feedback enhanced students' completion rate of online learning activities and their study regularity. The treatment group exhibited superior performance in the final examination compared to the comparison group, providing evidence of the positive impact of LA-based feedback on students' course performance. The study represents an initial effort to utilize LA-based feedback to support students' SRL operations and course performance in an EFL context.

Experimental study on seismic performance of spatial and planar hoop-head mortise and tenon timber joints in historical architecture

This paper aims to present an experimental study investigating the seismic behaviour of spatial and planar hoop-head mortise and tenon (MT) timber joints in traditional Guangfu Ancestral Halls. The unique design of the external hoop head provides additional restraints for the tenon and mortise in these joints, endowing them with enhanced pull-out resistance and increased structural integrity compared to other types of MT connections commonly used in traditional timber-framed structures. The research commenced with material testing to determine the mechanical properties of Merbau wood used in this timber frame construction. Reversed cyclic loading tests were then performed on two planar and two spatial hoop-head MT timber joints. The experimental results demonstrated the favourable seismic performance of the hoop-head MT joints. All specimens failed within the MT joint area, exhibiting different failure modes based on varying connection configurations and tenon sizes. Furthermore, the spatial MT joints showed lower stiffness and bearing capacities compared to the planar MT joints of equivalent size. Their hysteresis curves, envelope curves, and cyclic stiffness degradation curves displayed greater asymmetry. These discrepancies can be attributed to the reduction in tenon sections necessary to accommodate the overlapping beams within the spatial joint core area.

Prediction of cavity inception speed and underwater radiated noise of a full-scale marine propeller based on a cavitation tunnel model test

Propeller cavitation is a dominant source of underwater radiated noise (URN) from shipping, and the appropriate evaluation of propeller noise mitigation measures is important for ecological ship design. In this study, a model test procedure and scaling method to predict the full-scale URN level from hydrodynamic noise sources were introduced. The cavity size based on the empirical vortex model was considered in the proposed scaling method for a quiet cruise condition with isolated tip vortex cavitation. This relation provides information on the equivalent cavitation number for the model test to have the same relative radius as that of the full-scale tip vortex cavitation. The alternative test cavitation number can also be chosen as close as possible to the point that gives the equivalent tip vortex cavity size if sheet cavitation exists in the condition for the equivalent cavity size. In this case, additional noise scaling should be performed using the ratio of the tip vortex cavity radii. The new scaling exponent introduced in this study varies according to the distance from the cavitation inception condition and shows a decreasing trend from the value at the inception condition as the equivalent cavitation number for the model test decreases. The scaled URN levels based on the proposed method showed reasonable agreement with the measurement results of a full-scale ship. Finally, the noise reduction effect of the specially designed wake control fin and propeller was investigated through a comparative model test following the proposed scaling strategy, and significant noise reductions were observed with changes in the design configuration.

Biomechanical properties of non-flight vibrations produced by bees.

Bees use thoracic vibrations produced by their indirect flight muscles for powering wingbeats in flight, but also during mating, pollination, defence and nest building. Previous work on non-flight vibrations has mostly focused on acoustic (airborne vibrations) and spectral properties (frequency domain). However, mechanical properties such as the vibration's acceleration amplitude are important in some behaviours, e.g. during buzz pollination, where higher amplitude vibrations remove more pollen from flowers. Bee vibrations have been studied in only a handful of species and we know very little about how they vary among species. In this study, we conducted the largest survey to date of the biomechanical properties of non-flight bee buzzes. We focused on defence buzzes as they can be induced experimentally and provide a common currency to compare among taxa. We analysed 15,000 buzzes produced by 306 individuals in 65 species and six families from Mexico, Scotland and Australia. We found a strong association between body size and the acceleration amplitude of bee buzzes. Comparison of genera that buzz-pollinate and those that do not suggests that buzz-pollinating bees produce vibrations with higher acceleration amplitude. We found no relationship between bee size and the fundamental frequency of defence buzzes. Although our results suggest that body size is a major determinant of the amplitude of non-flight vibrations, we also observed considerable variation in vibration properties among bees of equivalent size and even within individuals. Both morphology and behaviour thus affect the biomechanical properties of non-flight buzzes.

Accommodating and Extending Various Models for Special Effects Within the Generalized Partially Confirmatory Factor Analysis Framework.

Special measurement effects including the method and testlet effects are common issues in educational and psychological measurement. They are typically covered by various bifactor models or models for the multiple traits multiple methods (MTMM) structure for continuous data and by various testlet effect models for categorical data. However, existing models have some limitations in accommodating different type of effects. With slight modification, the generalized partially confirmatory factor analysis (GPCFA) framework can flexibly accommodate special effects for continuous and categorical cases with added benefits. Various bifactor, MTMM and testlet effect models can be linked to different variants of the revised GPCFA model. Compared to existing approaches, GPCFA offers multidimensionality for both the general and effect factors (or traits) and can address local dependence, mixed-type formats, and missingness jointly. Moreover, the partially confirmatory approach allows for regularization of the loading patterns, resulting in a simpler structure in both the general and special parts. We also provide a subroutine to compute the equivalent effect size. Simulation studies and real-data examples are used to demonstrate the performance and usefulness of the proposed approach under different situations.

Analysis of low temperature flexural creep properties of mineral powder reinforced asphalt MPRA through combined experimentation and finite element simulation

The low temperature flexural creep properties of Mineral Powder Reinforced Asphalts (MPRAs) are systematically studied using both experimentations and finite element (FE) simulations. First, a new method to obtain the viscoelastic parameters of the pure asphalt is introduced. A digital twin for MPRA is then generated using Matlab, and a reliable simplification of the geometric dimension is adopted and verified. Second, a novel concept of equivalent particle size (EPS) is introduced in the FE models to represent the agglomeration effect of mineral powder in an asphalt. Four different basic EPSs are adopted to simulate the MPRAs with different powder-cement ratios. Third, the exponential function between EPS and simulated creep stiffness is fitted, and a reliable EPS for a specific sample is deduced using the fitted exponential function and experimental result, and it is verified using FE simulations. Finally, the digital twin for the MPRA proposed in this study is further verified by predicting the flexural creep properties at another temperature. The results show that the novel method to obtain the pure asphalt viscoelastic parameters and the digital twin for MPRA are reliable. EPS proposed in this paper could suitably characterize the agglomeration effect of mineral powder in FE simulations. The stress and strain inside the asphalt matrix decrease with smaller EPS. An accurate EPS for a specific MPRA can be deduced using experimental results and the exponential function fitted using different EPSs and simulated creep stiffness. Creep stiffness is larger under bigger powder-cement ratios, whereas the creep rate shows an opposite trend. Mineral powder tends to agglomerate more under bigger powder-cement ratios because the accurate EPS is bigger for MPRA having a bigger powder-cement ratio. The reliable digital twin for MPRA so obtained could be used to consistently predict the flexural creep properties at a different temperature.

Dynamics and capability of along orbit debris self-collecting with rotating constant magnets

Orbital debris with equivalent size of 1∼10 cm is hard to be detected and its number is huge, which is the most harmful to on-orbit spacecraft while there is still no effective removal means. Inspired by vacuum cleaner, applying the conductive property of orbital debris and the physical law that variable magnetic flux would induce eddy current on the surface of a conductive material, this paper put forward a novel approach of ‘along orbit debris self-collecting with rotating constant magnetic dipole array’. Based on dynamic modeling, self-collecting feasibility and control capability analysis, evolution law of relative orbital motion with induced magnetic force derivation, and on-orbit debris magnetic collecting numerical simulation, this novel approach has been verified and the corresponding requirements of magnetic collector are put forward. In addition, this paper also gave how to use several key parameters to adjust the region of along orbit debris self-collecting, and pointed out several problems needing to be researched in-depth for actual application.

Additively manufactured Ti-5Al-5V-5Mo-3Cr: Understanding defect-fatigue relationships

Ti-5Al-5Mo-5V-3Cr (Ti-5553), a near-β Ti alloy, possesses an excellent combination of strength, toughness, and strength-to-weight ratio, and due to its poor machinability characteristic, it is poised to be additively manufactured for key structural applications. This study examines the micro-/defect-structure and mechanical behavior, including both tensile and fatigue, of laser powder bed fused Ti-5553. The tensile and fatigue specimens are fabricated in two locations on the build plate with respect to the powder feed direction, i.e., west (away from powder reservoir) and east (near powder reservoir), to examine the location dependence of the mechanical properties. In addition, fatigue specimens are furnished in both un-machined and machined surface conditions. It is found that the volumetric defect content is higher for the west specimens than the ones in the east; however, tensile and fatigue properties are not affected by part location. The insensitivity of fatigue lives to the part location can be ascribed to specimens having statistically equivalent defect size distribution near the surface, as fatigue failures are primarily initiated by critical defects on or in the vicinity of the surface in un-machined and machined specimens.

TOBE-Costas arrays for fast high-resolution 3D power Doppler imaging.

2D sparse arrays and row-column arrays are both alternatives to 2D fully-addressed arrays with lower channel counts. Row-column arrays have recently demonstrated fast 3D structural and flow imaging but commonly suffer from high grating lobes or require multiplexing to achieve better quality. 2D sparse arrays enable full-volume acquisitions for each to transmit event, but plane-wave transmissions with them usually lack quality in terms of uniformity of wavefronts. Here, we propose a novel architecture that combines both types of these arrays in one aperture, enabling imaging using row-column or sparse arrays alone or a hybrid imaging scheme where the row-column array is used in transmission and a 2D sparse array in reception. This hybrid imaging scheme can potentially solve the shortcomings of each of these approaches. The sparse array layout chosen is a Costas array, characterized by having only one element per row and column, facilitating its integration with row-column (TOBE) arrays. We simulate images acquired with TOBE-Costas arrays using the hybrid imaging scheme and compare them to row-column and sparse spiral arrays of equivalent aperture size (128λ×128λ at 7.5 MHz) in ultrafast plane-wave imaging of point targets and 3D power Doppler imaging of synthetic flow phantoms. Our simulation results show that TOBE-Costas arrays exhibit superior resolution and lower side lobe levels compared to plane-wave compounding with row-column arrays. Compared to density-tapered spiral arrays, they provide a larger field of view and finer resolution.

Complete series method (CSM): a convenient method to reduce daily heterogeneity when evaluating the regeneration time (RT) of insecticide-treated nets (ITNs)

Background“Regeneration time” (RT) denotes the time required to obtain a stable mortality rate for mosquitoes exposed to insecticide-treated nets (ITNs) after three consecutive washes of a net in a day. The RT informs the wash interval used to artificially age ITNs to simulate their lifetime performance under user conditions (20 washes). RT was estimated following World Health Organization (WHO) longitudinal method (LM) procedures. Longitudinal evaluation may introduce heterogeneity due to mosquito batch variability, complicating RT determination. To overcome this, nets at each stage of regeneration (i.e., 1, 2, 3, 5 and 7 days post wash) were prepared in advance and refrigerated; then, a complete regeneration series was tested with a single mosquito batch on 1 testing day, completing four series over 4 days. This study compared the complete series method (CSM) against the LM.MethodsThe overall heterogeneity in the methods for estimating RT of one incorporated alpha-cypermethrin and piperonyl butoxide (PBO) and one incorporated permethrin with PBO ITNs was determined using laboratory-reared resistant Anopheles arabiensis under standard laboratory conditions. LM methods and CSM were compared in two experiments with refrigerated nets acclimated for (i) 2 h (test 1) and (ii) 3 h (test 2). Four regeneration replicates per day were tested per ITN product with 50 mosquitoes exposed per replicate (equivalent sample size to LM). The heterogeneity from these methods was compared descriptively.ResultsThe intra-method variability for unwashed pieces was minimal, with variance of 1.26 for CSM and 1.18 for LM. For unwashed nets, LM had substantially greater variance and ratio of LM:CSM was 2.66 in test 1 and 2.49 in test 2. The magnitude of mortality measured in bioassays depended on sample acclimation after refrigeration.ConclusionsThe CSM is a convenient method for determining the regeneration times. ITNs are prepared in advance, reducing pressure to prepare all samples to start on a single day. A complete regeneration series of samples is removed from the refrigerator, defrosted and evaluated on a single day with one mosquito batch reducing the influence of mosquito batch heterogeneity on results. Replicates can be conducted over several days but do not have to be conducted on consecutive days, allowing easy facility scheduling.Graphical

Ability to pay and catastrophic health expenditure of urban and rural deceased households over the past decade (2009-2018).

Examining the equity of health care and financial burden in households of deceased individuals in urban and rural areas is crucial for understanding the risks to both national and individual household finances. However, there is a lack of research on catastrophic health expenditure (CHE) in these households, specifically in urban and rural contexts. This study aims to identify the ability to pay and equity of CHE for both households of deceased individuals in urban and in rural areas. This study analysed data from the Korea Health Panel for 10 years (2009-2018) and targeted 869 deceased individuals and their households in the Republic of Korea (South Korea). Annual household income and living costs were adjusted based on equivalent household size, and the difference between these values represented the household's ability to pay. Out-of-pocket (OOP) expenditure included copayments and uninsured healthcare expenses for emergency room visits, inpatient care, outpatient treatments and prescription medications. CHE was defined as OOP expenditure reaching or exceeding 40% of the household's ability to pay. ANCOVA was performed to control for confounding variables, and the equity of CHE prevalence between urban and rural area was assessed using χ2 analysis. Compared to urban households, the rural households of deceased individuals had, respectively, fewer members (2.7 v 2.4, p=0.03), a higher rate of presence of a spouse (63.8% v 70.7%, p=0.04) and a higher economic activity rate (12.7% v 20.5%, p=0.002). The mean number of comordities before death was 3.7 in both urban and rural areas, and there was no difference in the experience of using over-the-counter medicines for more than 3 months, emergency room, hospitalisation, and outpatient treatment. In addition, annual household OOP expenditures in urban and rural areas were US$3020.20 and US$2812.20, respectively, showing no statistical difference (p=0.341). This can be evaluated as a positive effect of various policies and practices aimed at alleviating urban-rural health equity. However, the financial characteristics of the household of the deceased in the year of death differed decisively between urban and rural areas. Compared to urban households, the annual income of rural households (US$15,673.80 v US$12,794.80, respectively, p≤0.002) and the annual ability to pay of rural households (US$14,734.10 v US$12,069.30, respectively, p=0.03) were lower. As a result, the prevalence of CHE was higher in rural areas than in urban areas (68.3% v 77.6%, p=0.003). The findings of this study highlight the higher risk of CHE in rural areas due to the lower income level and ability to pay of the household of the deceased. It is evident that addressing the issue of CHE requires broader social development and policy efforts rather than individual-level interventions focused solely on improving health access and controlling healthcare costs. The findings of this study contribute to the growing evidence that income plays a crucial role in rural health outcomes.

Experimental Study on the Clogging Performance of Waste Slag

The fine particles around a mining area are easy to transport under the climatic and hydrological actions such as rainfall, that causes the change in the permeability of accumulated slag and increases the hazard probability of slag debris flow. In this study, eight experiments were designed to discuss the influence of fine particle migration on the permeability characteristics and clogging of slag accumulation in different graded particles and different dry densities. The results of experiments with coarse slags of five different particle sizes show that the ratio ranging from four to six in the coarse slag size and fine size caused a significant clogging phenomenon. It is confirmed that the shape of the particles is one of the factors affecting the clogging of coarse soil besides the coarse and fine particle size, and the clogging assessment criterion for slag and the corresponding clogging patterns based on the slag shape characteristics are given. And through three kinds of different dry density-graded slag, three clogging experiments were completed to verify the clogging standard and clogging particle size. The experimental results show that the clogging particle size obtained by the clogging criteria can effectively reduce the permeability of slag accumulation, and it is considered that the equivalent particle size and particle shape characteristics are the main factors affecting the clogging performance of accumulation, while the dry density of deposits has no significant influence on it.

Assessment of Roughness Characterization Methods for Data-Driven Predictions

A comparative analysis is undertaken to explore the impact of various roughness characterization methods as input variables on the performance of data-driven predictive models for estimating the roughness equivalent sand-grain size ks\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$k_s$$\\end{document}. The first type of model, denoted as ENNPS\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ ext {ENN}_\ ext {PS}$$\\end{document}, incorporates the roughness height probability density function (p.d.f.) and power spectrum (PS), while the second type of model, ENNPA\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ ext {ENN}_\ ext {PA}$$\\end{document}, utilizes a finite set of 17 roughness statistical parameters as input variables. Furthermore, a simplified parameter-based model, denoted as ENNPAM\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ ext {ENN}_\ ext {PAM}$$\\end{document}, is considered, which features only 6 input roughness parameters. The models are trained based on identical databases and evaluated using roughness samples similar to the training databases as well as an external testing database based on literature. While the predictions based on p.d.f. and PS achieves a stable error level of around 10% among all considered testing samples, a notable deterioration in performance is observed for the parameter-based models for the external testing database, indicating a lower extrapolating capability to diverse roughness types. Finally, the sensitivity analysis on different types of roughness confirms an effective identification of distinct roughness effects by ENNPAM\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ ext {ENN}_\ ext {PAM}$$\\end{document}, which is not observed for ENNPA\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ ext {ENN}_\ ext {PA}$$\\end{document}. We hypothesize that the successful training of ENNPAM\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ ext {ENN}_\ ext {PAM}$$\\end{document} is attributed to the enhanced training efficiency linked to the lower input dimensionality.

Durability analysis of large and medium-sized unmanned aerial vehicles based on load spectrum and probabilistic fracture mechanics

The analysis of unmanned aerial vehicle (UAV) durability is crucial for cost-effective repair and maintenance. Assessing the degree of damage and predicting the economic lifespan of a UAV is a critical component of its design and use. To evaluate the durability of large and medium-sized UAVs, data is gathered, and simulations are performed under real-world working conditions. The analysis includes creating a crack growth model for small cracks and determining the distribution of crack sizes, estimating the distribution of Time to Crack Initiation (TTCI), and calculating the general Equivalent Initial Flaw Size (EIFS) distribution. The results obtained from these analyses meet the UAV’s flight hour requirements and help to predict its economic life. This prediction is also beneficial for managing and maintaining the UAV’s life cycle.

Surface integrity and corrosion resistance of 18CrNiMo7-6 gear steel subjected to combined carburized treatment and wet shot peening

Typically, a cost-effective and versatile carburizing process is used to improve the surface integrity of high-value-added gear components. In this study, carburized treatment and wet shot peening (WSP) were applied to increase the corrosion resistance of 18CrNiMo7-6 gear steel. The surface integrity and corrosion resistance after carburizing and combined treatment (carburized treatment + WSP) were analyzed. The results indicated that the combined treatment converted the retained austenite surface layer within approximately 45 μm from the surface into the martensitic phase, with a 13.9 % reduction in equivalent grain size and a 23.6 % increase in dislocation density compared with carburizing. Furthermore, electrochemical experiments in a 3.5 wt% NaCl solution indicated that the combined treatment process increased the corrosion resistance compared with carburizing (55.4 % lower corrosion current density and a higher Fe2+/Fe3+ ratio). Despite the high surface roughness obtained with combined treatment, the improved corrosion resistance is primarily ascribed to the high compressive residual stress and dislocation density. This study provides insights into the surface strengthening design of 18CrNiMo7-6 gear steel for corrosive environments—particularly the synergistic strengthening effect of carburizing and WSP.

Replacing nitrogen in mineral fertilizers with nitrogen in maize straw increases soil water-holding capacity

Soil water-holding capacity decreases due to long-term mineral fertilizer application. The objective of this study was to determine how replacing mineral fertilizer with maize straw affected the soil water retention curve, soil water content, soil water availability, and soil equivalent pore size. Replacement treatments in which 25% (S25), 50% (S50), 75% (S75), and 100% (S100) of 225 kg ha−1 nitrogen from mineral fertilizer (CK) was replaced with equivalent nitrogen from maize straw were conducted for five years in the Loess Plateau of China. The Gardner model was used to fit the soil water retention curve and calculate the soil water constant and equivalent pore size distribution. The results indicated that the Gardner model fitted well. Replacing nitrogen from mineral fertilizer with nitrogen from straw increased soil specific water capacity, soil readily available water, soil delayed available water, soil available water, soil capillary porosity, and soil available water porosity over time. S25 increased field capacity and wilting point from the fourth fertilization year. S50 enhanced soil readily available water, soil delayed available water, soil available water, and soil available water porosity from the fifth fertilization year, whereas S25 and S75 increased these from the third fertilization year or earlier. Soil specific water capacity, soil readily available water, soil delayed available water, soil available water, soil capillary porosity, and soil available water porosity could better reflect soil water-holding capacity and soil water supply capacity compared with field capacity and wilting point.

Fatigue life estimation of nickel-based single crystal superalloy with different inclined film cooling holes: Initial damage quantification and coupling of damage-fracture mechanics models

Quantitative assessment of the initial damage state of a structure and fatigue life prediction on this basis, especially when it is sensitive to manufacturing quality, is crucial for both engineering application and material science. Traditional solutions based on fracture or damage mechanics either require precise constitutive relationships and cumbersome physical mechanism models or simply ignore the initial damage state. This study developed a novel equivalent initial flaw size (EIFS) quantitative evaluation method for film cooling holes in Nickel-based single crystal superalloy turbine blades to address the strong correlation between the initial damage in and fatigue life of the material. The temperature and stress field differences at the edges of holes with different inclination angles were simulated using a solid-liquid-gas three-phase level-set model and considered to represent the same initial damage. Next, the coupled damage–fracture mechanics model was used to achieve equivalent crack insertion, crack propagation, and fatigue life prediction based on the EIFS. The results indicate that this method can provide a highly robust EIFS distribution interval and that the crack geometry correction factor and EIFS distribution range are weakly correlated with the loading conditions (with an error within 2 %). The EIFS-based fatigue life predictions demonstrated a notable degree of accuracy, with the majority of the predicted and experimental fatigue lives falling within a three-fold dispersion band and all predictions remaining confined within a five-fold dispersion band of the actual lifetime. These results represent a substantial advancement in accuracy compared to traditional damage mechanics predictions. Therefore, this study provides a powerful approach for evaluating the fatigue life of turbine blades considering the initial damage state and can be widely applied to guide drilling process optimization and blade fatigue analysis.

A Refined Thin-Film Model for Drug Dissolution Considering Radial Diffusion - Simulating Powder Dissolution.

We aim to present a refined thin-film model describing the drug particle dissolution considering radial diffusion in spherical boundary layer, and to demonstrate the ability of the model to describe the dissolution behavior of bulk drug powders. The dissolution model introduced in this study was refined from a radial diffusion-based model previously published by our laboratory (So et al. in Pharm Res. 39:907-17, 2022). The refined model was created to simulate the dissolution of bulk powders, and to account for the evolution of particle size and diffusion layer thickness during dissolution. In vitro dissolution testing, using fractionated hydrochlorothiazide powders, was employed to assess the performance of the model. Overall, there was a good agreement between the experimental dissolution data and the predicted dissolution profiles using the proposed model across all size fractions of hydrochlorothiazide. The model over-predicted the dissolution rate when the particles became smaller. Notably, the classic Nernst-Brunner formalism led to an under-estimation of the dissolution rate. Additionally, calculation based on the equivalent particle size derived from the specific surface area substantially over-predicted the dissolution rate. The study demonstrated the potential of the radial diffusion-based model to describe dissolution of drug powders. In contrast, the classic Nernst-Brunner equation could under-estimate drug dissolution rate, largely due to the underlying assumption of translational diffusion. Moreover, the study indicated that not all surfaces on a drug particle contribute to dissolution. Therefore, relying on the experimentally-determined specific surface area for predicting drug dissolution is not advisable.

One-Dimensional Modeling of the Pressure Loss in Concrete Pumping and Experimental Verification

An accurate formula for calculating the pressure loss in concrete pumping plays a significant guiding role in the design and service process of pump trucks. Based on the flow characteristics of concrete pumping, a straight pipe one-dimensional model for the pressure loss is developed, in which both the viscous force of the mortar in the lubrication layer and the blocking effect of coarse aggregate particles are considered. First, the complex geometrical shapes of the aggregate particles are geometrically reconstructed by using a HandySCAN noncontact scanner and the reverse modeling software Geomagic Design X (v.19.0.2). Then, the equivalent spherical size of nonspherical aggregate particles is calculated according to the equal hydraulic radius principle. The blocking effect of the aggregate particles is converted into the wall roughness. Finally, an explicit expression for the pressure loss in concrete pumping is deduced by using Modi’s equation, Bernoulli’s equation, and Darcy’s formula, and the calculated value is compared with the measured value at a corresponding experimental site. The results indicate that the pressure loss values calculated with the one-dimensional flow model are closer to the actual pumping pressure loss values. The relative error between the results and the actual pumping pressure loss value is about 20.2%.

Formation design for interplanetary shock imaging interferometric array

Continuous monitoring of interplanetary coronal mass ejections (CMEs) plays a vital role in modelling of CME heliospheric propagation and improving space weather prediction, which remains a significant challenge due to the lack of effective observations. The type II radio bursts produced by CME-driven interplanetary shocks provide an opportunity for us to imaging the CMEs and their shocks through interferometry technology. This paper proposes a concept for the program of CME/shock imaging through low-frequency radio interferometry based on satellite formation. The formation consists of one mother satellite and seven daughter satellites, forming an interferometric array with the equivalent aperture size of 100 km to conduct three-dimensional tomography of CME/shock at 0.1 MHz ∼ 30 MHz. Two types of satellite formations, including a linear formation and a coplanar formation, are designed to provide different options of baseline distributions. Then, the fuel budgets for formation deployment and maintenance are analyzed. Besides, GNSS (Global Navigation Satellite System) differential positioning is discussed for relative measurement between the mother and daughter satellites. Finally, imaging simulations are performed to demonstrate the imaging performances of the interferometric array. The proposed interferometric formation will furnish essential insights into the Earth-directed CME propagation and provide critical and unprecedented observation data for space weather forecasting.