Effect Size Research Articles

Detecting overfitting by examining residuals in autoregressive models

The aim of this study is to see how overfitting can be detected using non-rigorous analysis of residuals. The well-known statistical packages was used to simulate data from stationary autoregressive models with Gaussian white noise with mean 0 and variance one. In order to see the effect of realization size on our findings, the sample size 50 was used as an example of small realization and the sample size 500 was used as an example of large realization. The method of maximum likelihood was used in the fitting of autoregressive models to the simulated data which is available in the statistical package R. Interesting and promising results were obtained. Our study seems to suggest that comparing estimates with their standard errors is the only reliable criterion in spotting or detecting overfitting. To make sure that the defect in the behavior of the residuals is due only to the over, we used only the same class of models in the simulation and the fitting.

The effect of transformer sizing and load variability on harmonics generated in a Nigerian university

This study investigates the impact of transformer sizing and load variability on the generation of harmonics in the distribution network of the Federal University of Technology, Akure (FUTA), Nigeria. The analysis focuses on Total Harmonic Distortion Voltage (THDv) at various Points of Common Coupling (PCCs) connected to different transformer capacities. Results indicate that PCCs linked to 500 kVA transformers exhibit THDv values ranging from 0.9% to 21.05%, generally falling within acceptable limits, albeit with some outliers. In contrast, PCCs associated with 200 kVA transformers display a broader and more concerning THDv range, from 0.65% to 65%. Additionally, the study reveals a significant increase in THDv at night compared to daytime, attributed to the higher prevalence of non-linear loads during off-peak hours. These findings highlight the critical role of transformer sizing and load patterns in managing harmonic distortion, underscoring the need for effective power quality management strategies within university distribution networks.

Review of Electrical Steels with their Properties and Recent Trends for Improvement

Objectives: This review study provides a thorough analysis of the magnetic behavior and characteristics of electrical steels, including established and novel materials (3%wt Silicon). Methods: We investigate how composition, microstructure, and processing methods affect the magnetic performance of these steels as well as the basic principles guiding their behavior. Thermomechanical processing can be observed for its impact on the material’s microstructure and magnetic properties. This review discusses testing over samples for conventional processes for different % of cold worked or strain hardening and annealing at higher temperatures i.e., 1200°C. For uncertainties regarding the impact of impurities or inclusions on their magnetic properties, the study was carried out to know the effect of cerium addition on the material’s magnetic properties of the material. Findings: It was observed that rolling temperature has significant effect over magnetic properties of the material. A notable improvement in the magnetic permeability of the material and its critical performance metric for soft magnetic materials is indicated by the increase in “Gamma max”. Similarly, the effects of compressive stresses, doping effect, grain size, annealing, and other manufacturing processes were studied, and observed their impact on magnetic properties. This review discusses the literature on future scope with the latest trends. This helps clarify the trade-offs associated with maximizing electrical steels for certain uses. Novelty: This study presents a novel approach towards electrical steel and its magnetic properties by incorporating different alloying elements and optimizing rolling & annealing parameters. A key innovation is the application of machine learning and neural network to predict and optimize material behavior, core loss and provide methods to improve magnetic properties of electrical steels. Significance: Electrical steels are crucial in transformers and electric motors, enhancing efficiency by minimizing energy losses and improving magnetic performance. This can be achieved by changing manufacturing parameters and operating conditions with the help of latest trends. Keywords: Electrical steel, Magnetic properties, Machine learning, Composition, Microstructure, Core loss

Microstructure Evolution and Cryogenic Impact Toughness Changes in Ce‐Containing Novel Cryogenic High‐Mn Austenitic Steel Weld Metals under Different Heat Inputs

The Ce‐containing novel cryogenic high‐Mn austenitic steel weld metals under different heat inputs are prepared by submerged‐arc welding to provide a satisfactory welding parameter scheme and further optimize its cryogenic impact toughness. The effect of heat input on microstructure, inclusion, and cryogenic impact toughness of weld metals are investigated via optical, scanning electron microscopy, electron backscatter diffraction, electronic probe microanalyzer, and cryogenic impact test. The results show that the dendrite arm spacing, segregation ratio of Mn, Si, and C elements and average effective grain size of the weld metals gradually increase, and the proportion of high‐angle grain boundaries decrease with the heat input increase from 11.91 to 20.24 kJ cm−1. The type of inclusions of weld metal with different heat inputs are all Ce2O3 and Ce2O2S. The number density of inclusions decreases monotonically from 5976 to 4912 mm−2, while the average size increases from 0.32 to 0.45 μm with the heat input increased. The increase in heat inputs consistently decreases the mean cryogenic impact toughness of weld metals from 123 to 102 J. The higher proportion of high‐angle grain boundaries and finer inclusions at lower heat input play the critical role in improving the cryogenic impact toughness.

Ring Size Effects on the Structures of Sandwich Compounds with a Stoichiometry of C12H12M (M = Ti–Ni)

Ring Size Effects on the Structures of Sandwich Compounds with a Stoichiometry of C₁₂H₁₂M (M = Ti–Ni)

Field experimental mode-pairing quantum key distribution with intensity fluctuations

The mode-pairing quantum key distribution (MP-QKD) protocol, which can achieve high key rates over long distances without phase locking, is a potential candidate for implementing intercity QKD. However, achieving precise control of the light source intensity in a field MP-QKD experiment is an exceedingly challenging task. In this Letter, we study the decoy-state MP-QKD protocol with light source intensity fluctuations. Furthermore, we propose a statistical analysis method based on the T-distribution to calculate confidence intervals of intensity fluctuations. Finally, in the field MP-QKD experiments, considering intensity fluctuations and the finite size effect, we obtain secure key rates of 1.03 × 10−6 bit/pair and 3.64 × 10−6 bit/pair for the symmetric (195.8 km) and asymmetric (127.7 km) cases, respectively.

The size of the size effect. The impact of splits of municipalities on the performance of local governments in Bulgaria, Croatia and Poland

The size of the size effect. The impact of splits of municipalities on the performance of local governments in Bulgaria, Croatia and Poland

Effect of Body Size on Plasma and Tissue Pharmacokinetics of Danofloxacin in Rainbow Trout (Oncorhynchus mykiss)

Danofloxacin is a fluoroquinolone antibiotic approved for use in fish. It can be used for bacterial infections in fish of all body sizes. However, physiological differences in fish depending on size may change the pharmacokinetics of danofloxacin and therefore its therapeutic efficacy. In this study, the change in the pharmacokinetics of danofloxacin in rainbow trout of various body sizes was revealed for the first time. The objective of this investigation was to compare the plasma and tissue pharmacokinetics of danofloxacin in rainbow trout of different body sizes. The study was conducted at 14 ± 0.5 °C in fish of small, medium, and large body size and danofloxacin was administered orally at a dose of 10 mg/kg. Concentrations of this antimicrobial in tissues and plasma were quantified by high performance liquid chromatography with ultraviolet detector. The plasma elimination half-life (t1/2ʎz), volume of distribution (Vdarea/F), total clearance (CL/F), peak concentration (Cmax), and area under the plasma concentration–time curve (AUC0–last) were 27.42 h, 4.65 L/kg, 0.12 L/h/kg, 2.53 µg/mL, and 82.46 h·µg/mL, respectively. Plasma t1/2ʎz, AUC0–last and Cmax increased concomitantly with trout growth, whereas CL/F and Vdarea/F decreased. Concentrations in liver, kidney, and muscle tissues were higher than in plasma. Cmax and AUC0–last were significantly higher in large sizes compared to small and medium sizes in all tissues. The scaling factor in small, medium, and large fish was 1.0 for bacteria with MIC thresholds of 0.57, 0.79, and 1.01 µg/mL, respectively. These results show that therapeutic efficacy increases with body size. However, since increases in danofloxacin concentration in tissues of large fish may affect withdrawal time, attention should be paid to the risk of tissue residue.

Effects of Thickness and Grain Size on Harmonic Generation in Thin AlN Films

High-harmonic generation from solid films is an attractive method for converting infrared laser pulses to ultraviolet and vacuum ultraviolet wavelengths and for examining the films using the generation process. In this work, AlN thin films grown on a sapphire substrate are studied. Below-band-gap third harmonics and above-band-gap fifth harmonics were generated using a Ti:sapphire oscillator running at 800 nm. A strong enhancement of the fifth-harmonic signal in the forward direction was observed from thicker 39 nm and 100 nm films compared to thinner 8 nm and 17 nm films. For the fifth harmonic generated in the backward direction, and also for the third harmonic in both the forward and backward directions, only a weak dependence of the harmonic signal on the film thickness was measured. Using both X-ray diffraction and dependence of the fifth harmonic on the laser polarization measurements, these behaviors are attributed to the crystallization and the grain size of the films, promising fifth-harmonic generation as a suitable tool to study AlN film properties.

Investigation of the effect of crystal size on the piezoelectric features of lead-free barium titanate ceramic using molecular dynamics simulation.

This study investigated the piezoelectric properties of BaTiO3 ceramics with different sizes through molecular dynamics simulations. The results show that all samples reached thermal equilibrium at 300K and equilibrium in potential energy within 10ns, confirming effective equilibration. As the size of the ceramics increased, the mean square displacement and diffusion coefficients decreased from 0.217 and 0.0034 to 0.1934 Å2 and 0.003 Å2/ns, attributed to a more uniform microstructure with fewer defects, resulting in reduced ion mobility. Furthermore, saturation polarization, residual polarization, and coercive field values increased from 0.35, 0.1, and 0.175 to 0.42 C/m2, 0.16 C/m2, and 0.282 MV/m, respectively, with increasing sample size, highlighting enhanced polarization responses due to a greater volume of ferroelectric material. Larger barium titanate (BaTiO3) crystals can have better polarization due to more domains aligning, but they may not deform as much (lower strain) because the walls among those domains can't move freely. While improved domain alignment contributed to higher polarization, the increased stress can restrict the mobility of the domain walls. These findings provided valuable insights into the size-dependent behavior of BaTiO3 ceramics, essential for optimizing their applications in electronic devices and sensors. The study underscored the importance of understanding microstructural effects on material properties for future advancements in ferroelectric technology.

Reverse Size Effect of the Unconfined Compressive Strength of Crystalline Rock: A Grain-Scale Perspective

Reverse Size Effect of the Unconfined Compressive Strength of Crystalline Rock: A Grain-Scale Perspective

The Effect of Microplastics with Different Types, Particle Sizes, and Concentrations on the Germination of Non-Heading Chinese Cabbage Seed

Microplastics (MPs) are a new type of pollutant widely distributed in the environment. The ecological risks caused by MPs are becoming increasingly serious, especially in cultivated land where pollution is more likely to accumulate. In this paper, the effects of different types, particle sizes, and concentrations of MPs on the seed germination of non-heading Chinese cabbage were analyzed to reveal their potential mechanisms. Five types of MPs, polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), polyethylene terephthalate (PET), and polystyrene (PS), were used for correlation analysis. The results showed that the effect of PVC and PET on seed germination was greater than that of PP, PS, and PE. PVC and PP promoted the growth of germinated seeds, while PET and PS showed a certain degree of inhibition. The effect of MPs with a particle size of 6.5–150 μm on seed germination was obvious. Low-concentration MPs (<1 g/L) had a weak inhibitory effect on seed germination. When the concentration was 1 g/L, 75 μm-PP, 75 μm-PVC, and 150 μm-PS promoted the growth of germinated seeds, while 48 μm PET showed inhibition. At high concentration, PP and PS inhibited amylase activity. In general, MPs’ effects showed significant differences according to different types, particle sizes, and concentrations.

Electrospinning of LaB6/PEDOT:PSS/PEO Fiber Composites of Unique Morphologies.

We present a direct electrospinning fabrication technique for the manufacture of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)/poly(ethylene oxide) (PEDOT:PSS/PEO) polymer fibers containing embedded cubic lanthanum hexaboride (LaB6) particles. We focus on the impact of relative humidity on the formation of uniform polymer fibers and show that a relative humidity of 5% is optimal, resulting in an average fiber thickness of 266 ± 88 nm. As the relative humidity is increased, the fibers contain beads as a consequence of Rayleigh instabilities. The addition of lanthanum hexaboride cubic particles to the polymer solution before electrospinning results in the encapsulation of the LaB6 particles inside the fibers. We investigate the effect of LaB6 particle size on morphology and observe that particles of ∼500 nm yield a fiber-cube-fiber morphology, while 2 μm particles result in fewer embedded cubes along the length of the polymer fibers. This phenomenon likely arises from electrodynamic interactions between the LaB6 particles in the polymer solution and the electric field lines generated during electrospinning between the spinneret and the collector. Our results display the versatility of the electrospinning technique in the fabrication of unique polymer/hexaboride composite fibers.

Filtration Behaviour of Ostrea edulis: Diurnal Rhythmicity Influenced by Light Cycles, Body Size and Water Temperature

AbstractDespite the existing studies on oyster physiology, it is a concern that, by ignoring the diurnal rhythmicity of feeding activities, the current knowledge on oyster filtration might be unrepresentative of their real filtration capacity. In the present study, the diurnal and nocturnal fluctuations of Ostrea edulis clearance rate were investigated for the first time under laboratory conditions, also considering the combined effects of water temperature and oyster size. A positive correlation was found between the mean clearance rate (CRm) and body size for both length and wet weight, with an average of 0.5 L h−1 and 0.1 L h−1 of water filtered by large and small adult oysters respectively during the 24-h experiment. A positive significant correlation between mean clearance rate and water temperature was found only for large oysters, suggesting further studies utilising temperature ranges closer to O. edulis thermal optimum are required to clarify the influence of temperature on oyster filtration activities across different size classes. The results of this study also showed a discontinuous ingestion of food by O. edulis throughout 24-h intervals, with higher values of clearance rate observed during hours of darkness at most temperatures for both size classes. This suggests photoperiod may have a potential influence on O. edulis filtration. Providing a better understanding of O. edulis filtration behaviour, these findings have implications for ecological restoration, aquaculture, and comparative studies on oyster bioenergetics and physiology, with direct applications to the development of predictive models and the assessment of ecosystem services provided by O. edulis habitat.

The recombination landscape of the barn owl, from families to populations.

Homologous recombination is a meiotic process that generates diversity along the genome and interacts with all evolutionary forces. Despite its importance, studies of recombination landscapes are lacking due to methodological limitations and limited data. Frequently used approaches include linkage mapping based on familial data that provides sex-specific broad-scale estimates of realized recombination and inferences based on population LD that reveal a more fine scale resolution of the recombination landscape, albeit dependent on the effective population size and the selective forces acting on the population. In this study, we use a combination of these two methods to elucidate the recombination landscape for the Afro-European barn owl (Tyto alba). We find subtle differences in crossover placement between sexes that leads to differential effective shuffling of alleles. LD based estimates of recombination are concordant with family-based estimates and identify large variation in recombination rates within and among linkage groups. Larger chromosomes show variation in recombination rates, while smaller chromosomes have a universally high rate which shapes the diversity landscape. We find that recombination rates are correlated with gene content, genetic diversity and GC content. We find no conclusive differences in the recombination landscapes between populations. Overall, this comprehensive analysis enhances our understanding of recombination dynamics, genomic architecture, and sex-specific variation in the barn owl, contributing valuable insights to the broader field of avian genomics.

A computational study of the size effect of SiO2 spherical nanoparticles in water solvent.

This study comprehensively describes the interaction between SiO2 spherical nanoparticles and water molecules as a solvent medium. Our goal is to provide valuable insights into the significance of nanoparticle size in understanding their behavior and the resulting changes in the physical properties of materials. Our results indicate that SiO2 nanoparticles exhibit a strong affinity for water, which increases with the nanoparticle size. Our investigation can be relevant for the design of new composite materials with applications ranging from medical prostheses to quantum electronics, optoelectronic devices, catalysis, and photoluminescence. We have concentrated on the study of the amorphous, where size effects seem to be more pronounced. A computational study was carried out within the molecular dynamics simulations framework available in the GROMACS-v2019.2 software, with force fields consistent with DFTand the CHARMM36 utilized in the molecular description of the systems. The water model used was the TIP3P implemented in CHARMM36 force fields. A comprehensive analysis of molecular interactions of various system configurations was performed, including radial distribution function (RDF), mean square displacement (RMSD), hydrogen bonding analysis,interfacial analysis, andstudying system size'seffect on mechanical properties.

Effect of Post Sizes and Citric Acid Treatment on the Bond Strength of Fiber Posts Using Self-Etch Resin Cement in Calcium Silicate–Based Sealer Treated Teeth

Abstract Objectives This study evaluated the effects of different post sizes and citric acid (CA) treatment on the bond strength of fiber posts cemented with self-etch resin cement in teeth obturated with calcium silicate–based sealer. Materials and Methods Seventy mandibular premolars were collected and randomly distributed to either a control group (no sealer) or experimental groups obturated with calcium silicate–based sealer (iRoot SP). The experimental groups were classified by post sizes—1.25 mm (no. 1), 1.375 mm (no. 2), and 1.50 mm (no. 3)—and the irrigants used (distilled water [DW] or CA). Prefabricated fiber posts were fixed using NX3 self-etch resin cement. Push-out bond strength was tested in the coronal and middle sections of the roots. Statistical Analysis The data were analyzed using a one-way analysis of variance (ANOVA), followed by a post hoc Duncan test. Results In the coronal section, post size no. 1 with DW showed significantly lower bond strength compared to the other experimental groups (p < 0.05). In the middle section, the larger post sizes (nos. 2 and 3) with CA treatment resulted in a significant increase in bond strength compared to the control group (p < 0.05). Conclusions iRoot SP negatively affected bond strength in the middle section of the canal. However, using larger post sizes (nos. 2 and 3) with CA treatment improved bond strength in the middle section.

Corporate governance and SME performance: Is technological capability a missing link?

Purpose This paper aims to examine the role of technological capability in the relationship between corporate governance and small and medium-sized enterprise (SME) performance. Design/methodology/approach Using panel data comprising 1,357 European SMEs from 2014 to 2020, this paper examines how technological capability acts as a mediator and moderator within the governance-performance nexus. Findings The results show a positive and significant link between corporate governance mechanisms and SME performance, as well as between technological capability and SME performance. In addition, this paper show that technological capability plays a crucial role in moderating and mediating the governance-performance relationship. Specifically, technological capability accentuates the positive effects of board size, the presence of outside directors and concentrated ownership on SME performance. Conversely, it attenuates the positive impacts of CEO duality and board gender diversity on SME performance. These results highlight corporate governance mechanisms and technological capability’s crucial role in significantly influencing SME performance. Practical implications The results suggest that SMEs should prioritize not only the implementation of effective corporate governance mechanisms but also the strategic utilization of technological innovations to boost performance. European policymakers are encouraged to enact supportive policies on technological innovation to strengthen the governance-performance dynamic. Originality/value This study contributes to the governance-performance literature by offering new insights into the critical role of technological capability, which has been previously explored in partial and fragmented ways.

A FEM-based model for failure initiation in the microstructure of gray cast iron under uniaxial compression

PurposeThe purpose of this study was to validate the feasibility of the proposed microstructure-based model by comparing the simulation results with experimental data. The study also aimed to investigate the relationship between the orientation of graphite flakes and the failure behavior of the material under compressive loads as well as the effect of image size on the accuracy of stress–strain behavior predictions.Design/methodology/approachThis paper presents a microstructure-based model that utilizes the finite element method (FEM) combined with representative volume elements (RVE) to simulate the hardening and failure behavior of ferrite-pearlite matrix gray cast iron under uniaxial loading conditions. The material was first analyzed using optical microscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) to identify the different phases and their characteristics. High-resolution SEM images of the undeformed material microstructure were then converted into finite element meshes using OOF2 software. The Johnson–Cook (J–C) model, along with a damage model, was employed in Abaqus FEA software to estimate the elastic and elastoplastic behavior under assumed plane stress conditions.FindingsThe findings indicate that crack initiation and propagation in gray cast iron begin at the interface between graphite particles and the pearlitic matrix, with microcrack networks extending into the metal matrix, eventually coalescing to cause material failure. The ferritic phase within the material contributes some ductility, thereby delaying crack initiation.Originality/valueThis study introduces a novel approach by integrating microstructural analysis with FEM and RVE techniques to accurately model the hardening and failure behavior of gray cast iron under uniaxial loading. The incorporation of high-resolution SEM images into finite element meshes, combined with the J–C model and damage assessment in Abaqus, provides a comprehensive method for predicting material performance. This approach enhances the understanding of the microstructural influences on crack initiation and propagation, offering valuable insights for improving the design and durability of gray cast iron components.

Effects of grain size and Al-Mn phase on the corrosion performance of hot-rolled AZ31 magnesium alloy

Effects of grain size and Al-Mn phase on the corrosion performance of hot-rolled AZ31 magnesium alloy