Effect Size Research Articles

Exploring multi-deformation mechanism and control of arc thin-walled structures during supercritical CO2 assisted micro milling

Titanium alloys are extensively utilized due to their exceptional corrosion resistance, high specific strength, temperature resilience, and biocompatibility. However, the challenges such as poor thermal conductivity, pronounced micro-machining size effects, and the sensitivity of micro-thin wall structures to residual stress complicate the machining of titanium alloy micro-thin walls. This paper investigates the use of supercritical CO2 to assist in arc micro-thin wall milling experiments of titanium alloys, aiming to elucidate the influence of various process parameters on micro-milling performance. The mesoscale prediction model developed in this study shows that the time-varying and static deflection deformations of micro-thin walls cooled by supercritical CO2 are approximately half of those observed under dry cutting conditions. To compare and optimize micro-milling performance metrics, an RVEA-entropy weight TOPSIS optimization scheme was developed, and combined with several high-dimensional multi-objective optimization algorithms. Integrating this with micro-milling finite element model, an iterative optimization and reverification strategy was proposed. The optimized parameters combination achieved through this method reduced micro-milling force, top deformation, and side deformation by 32.5 %, 24.6 %, and 24.3 %, respectively. The research approach and optimization strategy presented in this paper offer valuable insights for enhancing the machining precision of mesoscale titanium alloy micro-thin-wall structures.

Anisotropic Plastic Deformation Mechanism and Indentation Size Effect During Berkovich Nanoindentation Process of ZnSe Crystals in Micro-nanoscale

Anisotropic Plastic Deformation Mechanism and Indentation Size Effect During Berkovich Nanoindentation Process of ZnSe Crystals in Micro-nanoscale

Treating waste with waste: Treatment of textile wastewater using upcycled food waste as a pore-forming agent in the fabrication of ceramic membranes employing DOE/FFD design

This study investigates a novel method for food waste management by using it as a sustainable replacement for conventional pore-forming agents in ceramic membrane production. The membranes were analyzed using various techniques, including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and a universal testing machine. The morphologies of the membranes were observed using scan electron microscopy (SEM). The effects of particle size (45–125 μm), pore-forming agent (5–20 wt%), and sintering temperature (900–1150 °C) on the porosity and mechanical strength of the membranes were investigated using the Design of Experiments (DoE) and Response Surface Methodology (RSM). The optimized membrane was evaluated for its performance in filtering industrial textile wastewater. It achieved impressive results, with approximately 98.4 % removal of turbidity and 71.3 % removal of chemical oxygen demand. This research paves the way for optimizing ceramic membrane fabrication using upcycled food waste, promoting sustainability and offering potential solutions for both food waste management and industrial wastewater treatment challenges.

Host-guest mediated recognition and rapid extraction of Fusarium mycotoxins in cereals by nickel ferrite magnetic calix[4]arene-derived covalent organic framework fabricated in room-temperature

Fusarium mycotoxins are toxic secondary fungal metabolites and widely distributed in cereals. Herein, a nickel ferrite magnetic calix[4]arene-derived covalent organic framework (NiFe2O4@CX4-COF) was meticulously designed and synthesized using a room-temperature method for the enrichment of mycotoxins. The CX4-COF exhibited a porous crystalline network with an eclipsed AA-stacking configuration. The ingenious integration of NiFe2O4, supramolecular calix[4]arene and COF contributed to host-guest mediated recognition, size-selectivity and high adsorption capacity, rapidly reaching adsorption equilibrium within only 3 min. Simulation calculations revealed that the host-guest interaction, size effect and abundant binding sites facilitated synergistically recognize and capture mycotoxins. NiFe2O4@CX4-COF has successfully applied for simultaneous extraction and analysis of mycotoxins in cereals, achieving negligible matrix effects (−14% to 13%), high sensitivity (LODs of 0.003–0.014 μg/L) and satisfactory recoveries (74.4%–116%). This work provides a prospective platform for constructing tailored macrocycle-based COFs under mild conditions for precise recognition and accurate analysis of trace hazardous substances in food.

The response of public education spending to changes in student cohort sizes

ABSTRACT In this paper, we study the elasticity of educational spending with respect to changing student numbers, in a system where educational spending is autonomously determined at a regional level. While many studies focus on the potential effect of an ageing society on educational spending, only a few explicitly analyse the direct effect of changing cohort sizes. We find that education expenditures respond rather loosely to changing student numbers and that the elasticity strongly depends on regional and institutional settings. In rural areas, for instance, educational spending tends to be completely inelastic, which raises questions regarding both, efficiency and equity concerns.

Changes in the ideal body shape associated with adolescent rowing-ergometry performance following a 6-week training intervention: New scaling insights using three-dimensional allometry.

Scaling, to remove the effects of body size, is an important methodological approach for enabling an equitable comparison of performance differences between individuals who vary in anthropometric characteristics. Many previous studies using scaling in sport have done so based on only one or two anthropometric characteristics, with only one study to date adopting a three-dimensional approach. To apply a three-dimensional allometric model to rowing ergometer performance (REP) in adolescents, and to detect whether key 'scaling' parameters remain stable when scaling REP both before and after a 6-week training intervention. Novel three-dimensional allometric models were used, incorporating body mass, stature and waist circumference (WC) to detect the most appropriate body size dimension(s) and scaling parameters associated with REP before and after a 6-week training intervention. Using this more flexible and sensitive three-dimensional allometry demonstrated that, following 6-weeks of training, there was a change in the ideal body shape associated with REP. Before training, taller, but not heavier, adolescents performed better. After 6-weeks of training, older participants with a greater body mass but smaller WC performed better. Scaling approaches are important for evaluating performance differences between individuals of differing body size. The findings from the current study (using a novel three-dimensional allometry approach) emphasise that relatively subtle changes in individuals' behavioural characteristics, such as changes in their training/fitness status, can result in quite dramatic changes in the body dimension characteristics and scaling parameters deemed to be key for performance in activities such as REP.

Nanoparticle size: A critical role in enhancing oil recovery

In recent years, nanomaterials have shown great potential in the enhanced oil recovery (EOR) process due to their superior properties. However, the influence of particle size on EOR is not clear and hinders the application. Therefore, it is vitally important to investigate the effect of the particle size on the EOR performance. In this work, Fe3O4 nanoparticles with different sizes, including 20 nm, 100 nm, 200 nm, and 300 nm, were controllably synthesized and used to innovatively clarify the critical role of nanoparticles size in enhancing oil recovery. The effects of sizes on the recovery were investigated by combining the experimental results of interfacial tension, wetting angle, and spontaneous imbibition. The results revealed that Fe3O4 nanoparticles with smaller size, which have the stronger ability to reduce the interfacial tension and change the wetting angle, exhibit a favorable capacity to enhance oil recovery. Compared with the spontaneous imbibition oil recovery (24.36 %) of standard brine, the nanofluid containing 0.1 wt% Fe3O4 with the size of 20 nm can increase the recovery to 30.87 %. Based on the results of nuclear magnetic resonance, the spontaneous imbibition mechanism was proposed and the effect of size on recovery was analyzed. In addition, the superparamagnetism of Fe3O4 was utilized for recycling, avoiding the issue of significant losses of nanofluids in the existing research after injection. The secondary spontaneous imbibition was carried out, showing good environmental friendliness.

The critical role of size effect on internal damage and mechanical properties of flax fiber reinforced composites

The effect of the size on the strength of laminated artificial fiber reinforced composites has been extensive discussed during the design of large composites structure. With the trial as the structures in aerospace, civil engineering, automobile industry, the scaling of the properties of plant fiber reinforced composite should be studied. In this paper, the size effect and failure mechanism of tensile and impact properties of flax fiber reinforced composites were valuated. The effects of different area, thickness and volume on the tensile properties of composites were explored. Additionally, the failure mechanism of size effect on tensile specimens was proposed through the damage morphologies of composites. It is found that the twist of fiber bundle plays an important role in the size effect of composite thickness. Besides, the relationship between impact properties and size effect of composites was conducted, including the size of hammer, different impact energy and sample size. The curves of different types of impact samples were normalized to verify the linear rule in response stage. The crack length after impact was measured and the size effect of crack length was discussed. The size effect of crack area was studied by calculating the crack area with ultrasonic C-scan. Different “size effects” between flax fibers and artificial fibers were explored. The results are expected to provide a theoretical basis for the structural design of plant fiber reinforced composites.

Size effect of typical hygrothermal properties test values for building insulation materials

Thermal and moisture properties of building insulation materials are crucial input parameters for analyzing thermal and moisture transfer phenomena in building environments. Accurate determination of these parameters under different conditions is essential for the correct application and assessment of materials and envelope structures. However, numerous factors influence thermal and moisture properties, and while extensive research has been conducted on this topic, the effects of specimen size on typical thermal and moisture property test values remain unclear. To address the issue of unreliable data caused by random specimen sizes in thermal and moisture property testing of building insulation materials, this study selects three materials—expanded polystyrene (EPS), extruded polystyrene (XPS), and foamed cement—as test subjects to explore the size effects on typical thermal and moisture property test values. The results indicate that specimen size significantly affects the test values for typical thermal and moisture properties, with only a few experiments showing negligible size effects for certain materials. For foamed cement, recommended specimen sizes for thermal conductivity testing using the guarded hot plate method and the transient plane source method are 300 × 300 × 30 mm and 50 × 50 × 30 mm, respectively. Except for equilibrium moisture absorption experiments, the weight of other moisture property tests is generally represented by thickness > planar dimensions.

Deep insight into the effect of smithsonite particle size on surface heterogeneity and adsorption behavior: A case of fatty acid system

The studies for microfine mineral flotation have focused on the two main directions of increasing the apparent mineral particle size and reducing the bubble size, while little research has been reported on the special surface properties and adsorption mechanisms of mineral particles of different sizes. In this study, sodium oleate was chosen as a typical surfactant. The mechanism of the effect of smithsonite particle size on the heterogeneity and adsorption behavior of the mineral surface was explored in depth. Through microflotation experiments, BET area tests, Washburn contact angle tests, particle agglomeration tests, adsorption tests and inorganic carbon analysis, it was pointed out that the smaller the size of the particles, the greater the surface wettability, and the smaller the density and thickness of adsorbed oleate on the surface. The difficulty of encapsulating the mineral surface with a hydrophobic layer of oleate hydrocarbon chains, as well as suboptimal particle aggregation sizes, are key reasons for the poor flotation behavior of fine smithsonite. Furthermore, the inhomogeneity of active sites and charge distribution of surface components of smithsonite with different sizes was revealed from a microscopic point of view by DRIFT spectroscopic analysis, XPS analysis and zeta potential measurements. As the particle size of smithsonite decreases, the positive charge density on the surface is higher and the hydration tendency is more intense, hindering the adsorption of oleate. This work is expected to guide the full particle size recovery of minerals in the flotation from a novel microscopic point of view.

Enhanced chemiluminescence with sub-1 nanometer CuO-PMA nanosheets for the sensitive detection of quercetin

BackgroundChemiluminescence (CL) analysis, characterized by its simple instrumentation, high signal-to-noise ratio, wide linear range, and minimal background interference, has garnered increasing attention from researchers. Nanomaterials (NMs) have been explored to enhance CL intensity. Notably, sub-1 nanometer scale NMs are considered to hold significant untapped potential due to their size effects. The application of these sub-1 nanometer NMs in enhancing CL is anticipated to yield favorable results. Additionally, the low water solubility and bioavailability of quercetin glycosides lead to their presence in bodily fluids at only trace levels, highlighting the urgent need for efficient and rapid detection methods. ResultsIn this work, phosphomolybdic acid (PMA) was incorporated into CuO to synthesize sub-1 nanometer CuO-PMA nanosheets (SNSs) using a cluster-core co-assembly strategy. Conformational and structural characterization confirmed the successful synthesis of these nanosheets. The CuO-PMA SNSs were employed to enhance the CL emission of the luminol-H2O2 system, resulting in an increase of over 1000 times. The catalytic properties of CuO-PMA SNSs significantly facilitated the decomposition of H2O2, leading to an enhanced production of reactive oxygen species, which in turn induced the CL enhancement. Given that the antioxidant effect of quercetin would consume the reactive oxygen species generated during the catalysis, a decrease in CL intensity was anticipated. A CL sensor for quercetin detection was developed based on the CuO-PMA SNSs-luminol-H2O2 system, demonstrating a strong linear relationship (R2 = 0.9969) and a low detection limit of 0.31 nM. SignificanceThis research provides a strategy to enhance the CL intensity of the luminol-H2O2 system by using CuO-PMA SNSs, offering a highly sensitive assay for detecting quercetin concentrations. The method is characterized as a simple and cost-effective analytical strategy making CL analysis very attractive for chemical analysts.

Experimental study on multiscale strain localisation based on soil cell element model

The granular and natural characteristics of soil introduce size effects to its deformation and strength properties. Therefore, investigating the phenomenon of strain localisation in soil requires a multi-scale characterisation. This study examined the intrinsic scale patterns in samples with different sizes of reinforcing particles through triaxial compression tests. Additionally, the formation mechanism of microscopic shear bands was investigated using numerical simulation methods. Drawing from the soil cell model theory, the average strain energy release coefficient was introduced to validate the transformation of the overall strain energy of the specimen after reaching the peak stress. This reflects the progressive initiation and competitive process of multiple bands. The results indicate that samples with different sizes and types of reinforcing particles exhibit various failure patterns, including single-type, ‘x’-shaped, ‘v’-shaped, parallel and others. The soil exhibits size effects, with the ratio of intrinsic scale to particle size decreasing as the size of reinforcing particles increases. Prior to the stress peak, non-elastic dissipation energy begins to increase, indicating the initiation of plastic deformation in the soil. Localised strain zones are activated, and after the peak, there is a sharp increase in stress within the shear bands, accompanied by rebound outside the band.

Size Effects on the Magnetic Properties of a System of ε-Fe2O3 Nanoparticles Embedded in a SiO2 Xerogel Matrix

A representative series of samples consisting of fine ε-Fe2O3 nanoparticles uniformly distributed over the SiO2 xerogel matrix with an iron oxide content of 5‒33 wt % has been synthesized and studied by mutually complementary physical methods. It has been shown by the X-ray diffractometry and high-resolution electron microscopy examination that, with increasing iron oxide concentration, the average particle size <d> increases from 4 to 11 nm. According to the X-ray diffractometry and Mӧssbauer spectroscopy data, the samples with an iron oxide content of 5–20 wt % are single-phase, while at the highest Fe2O3 concentration (33 wt %), the β-Fe2O3 and α-Fe2O3 phases arise. As the average particle size <d> increases, a monotonic increase in coercivity HC and remanent magnetization MR of the synthesized systems at room temperature is observed, which is indicative of their magnetic hysteresis. The magnetic transition known to occur in the ε–Fe2O3 oxide manifests itself in all the investigated samples as a drastic change in the HC and MR values at 150–75 K. At the same time, a thorough analysis of the temperature dependence of the real part of the ac magnetic susceptibility χ′ has shown that the particles with a size smaller than a critical value of dC ∼ 6.5 nm do not undergo the magnetic transition and have a much lower magnetic anisotropy constant as compared with coarser particles (d >dC). It has been found that, in the low-temperature region, the magnetic moments of these fine particles experience superparamagnetic blocking. It has been established that the size effects that arise in ultra-fine ε–Fe2O3 particles has a serious impact on the macroscopic magnetic properties of the highly dispersed systems based on them.

Tensile properties and constitutive modeling of Kevlar29 fibers: from filaments to bundles

This paper experimentally investigates the tensile properties of Kevlar29 filaments and fiber bundles, revealing the size and strain rate effects on the mechanical properties of fiber bundles. The fracture modes and mechanisms of the fibers were analyzed, and viscoelastic constitutive models at the fiber bundle scale and constitutive models for filaments-bundles based on the Weibull distribution were established. The results show that Kevlar29 fiber bundles exhibit significant strain rate effects: as the strain rate increases, tensile strength and modulus increase, while fracture strain and toughness decrease. Under quasi-static loading, the fracture modes of the fibers are mainly fibrillation or shear flow, but as the strain rate increases, the failure modes shift towards brittle fracture. Both constitutive models can accurately predict the tensile properties of fiber bundles at different strain rates. The accuracy and applicability of the filament-to-bundle constitutive model were verified through numerical simulations, demonstrating that the model better describes the size effect of fibers and quantifies the damage to the fiber bundles.

Design of Enzyme Immobilized Zwitterionic Copolymer Nanogels and its Size Effect on Electrochemical Reaction

Design of Enzyme Immobilized Zwitterionic Copolymer Nanogels and its Size Effect on Electrochemical Reaction

Size effect on texture of multiscale Cu in Cu Nb nanocomposite wires

Size effect on texture of multiscale Cu in Cu Nb nanocomposite wires

Investigation of the effect of mineral composition and size on particle separation in Wet low and high intensities magnetic separators: An industrial case

Magnetic separation is used in ore processing to separate the minerals according to their magnetic susceptibility. Particle size also plays a role in the separation although few industrial results are presented in the literature to discuss this matter. Results from sampling industrial Wet Low Intensity Magnetic Separators (WLIMS) and Wet High Intensity Magnetic Separators (WHIMS) for processing an iron ore show that except for the strongly paramagnetic magnetite (Fe3O4), the recovery of minerals decreases with increasing particle size for both WLIMS and WHIMS. The examination of polished sections of the coarse size fractions from the reject streams of the WHIMS does not provide ground to suspect liberation to be responsible for the reduced recovery of coarse particles. Results also show that it is difficult to establish clear relationships between the mineral recoveries and their reported magnetic susceptibilities for WLIMS while for WHIMS a weak trend is observable.

Comprehensive CFD Analysis of Base Pressure Control Using Quarter Ribs in Sudden Expansion Duct at Sonic Mach Numbers

This study aims to assess the effect of rib size, shape, and location in a suddenly expanded flow at sonic Mach number. Flow from a converging nozzle is exhausted into a larger area of duct diameter of 18 mm. The geometric parameters considered are the area ratio, duct length, rib radius, and inertia parameters, which are considered the level of expansion at critical Mach number. In the present study, duct lengths were from 1D to 6D, rib radii considered were 1 mm to 3 mm, and rib locations were 0.5D, 1D, 1.5D, 2D, and 3D. Results show that when the ribs are placed near the reattachment point with a 3 mm radius, they are efficient and capable of reducing the suction in the recirculation zone and the base pressure, which was lower than the ambient pressure in the absence of ribs, is assorted larger than the back pressure. If the requirement is to equate the pressure at the base to ambient pressure, then a 2 mm radius is the right choice. Furthermore, the 1 mm rib cannot reduce the suction in the base region, and base pressure remains sub-atmospheric for the entire range of rib locations, as well as the NPRs of the present study. When the orientation of the ribs is changed, and the flow interacts with the flat surface instead of the curved surface, there is a marginal change in the flow pattern, and there is no significant change in the base pressure values.

Low-Temperature Rapid Drying of Viscous Sludge Via Non-Phase Change Based on Particle High-Speed Self-Rotation and Medium Dispersion in Cyclone

Drying operations are of grave importance to realize the reduction and utilization of sewage sludge resources, but the conventional thermal evaporation drying (TED) technology faces challenges due to the need for a large amount of thermal energy to conquer the phase-change latent heat of moisture. Herein, we report a non-phase change technology based on particle high-speed self-rotation in a cyclone for fast, low-temperature drying of viscous sludge with high moisture contents. Dispersed phase medium (DPM) is introduced into the cyclone self-rotation drying (CSRD) reactor to enhance the dispersion of the viscous sludge. The effects of carrier gas temperature, feeding rate, size, and proportion of DPM particles in the drying process are systematically examined. Under optimal operating conditions, the weighted content of moisture in the viscous sludge could be reduced from 80% to 15.01% in less than 5 s, achieving a high drying efficiency of 95.79%. Theoretical calculations also reveal that 89.26% of the moisture is removed through a phase change pathway, contributing to a 522-fold increase in the drying rate of CSRD compared to TED technology. This investigation presents a sustainable effective approach for high moisture viscous sludge treatment with low energy consumption and carbon emissions.

Deep water characteristics of electrodynamic transducers based on distributed-parameter equivalent circuit of acoustic cavity

The source level of the electrodynamic transducer with a passive pressure compensation airbag in ultra-low frequencies (bands below 100 Hz) decreases sharply with the increase in working depth. A theoretical model with a distributed-parameter equivalent circuit of the acoustic cavity was proposed to explore the mechanism of this phenomenon and find a way to improve the ultra-low frequency source level in deep water (over 200 m). The results indicate that the decrease in acoustic compliance of the cavity in deep water leads to an increase in resonant frequency, resulting in a decrease in source level in the ultra-low frequency band. The resonance frequency in deep water shows differences based on distributed and lumped parameter models. The resonance frequency test results of the prototype show that the theoretical results based on a distributed-parameter model proposed in this study are more consistent with the test values. The effects of the acoustic cavity's structural size, the acoustic parameters of the gas in the cavity, and the active pressure compensation method on the source level at different depths were analyzed. Results reveal that the acoustic performance in ultra-low frequency bands at large depths can be markedly improved using the active pressure compensation method.