Uniform Behavior Research Articles

Trends in null hypothesis significance testing: Still going strong

Null hypothesis significance testing (NHST) is among the most prominent and widely used methods for analyzing data. At the same time, NHST has been criticized since many years because of misuses and misconceptions that can be found extensively in the scholarly literature. Furthermore, in recent years, NHST has been identified as one reason for the replication crisis because many studies place too much emphasis on statistical significance for drawing conclusions. As a response to those problems, calls for actions have been raised, among others by the American Statistical Association (ASA), to rectify these issues, for instance, by modifying or even abandoning NHST. In this paper, we study the reaction of the community on these discussions. Specifically, we conduct a scientometric analysis of bibliographic records to investigate the publication behavior about the usage of NHST. We conduct a trend analysis for the general community, for specific subject areas and for individual journals. Furthermore, we conduct a change-point analysis to investigate if there are continued movements or actual changes. As a result, we find that for the general community NHST is more popular than ever, however, for particular subject-areas and journals there is a clear heterogeneity and no uniform publication behavior is observable.

Drying temperature effect on the characteristics of cationically polymerized kraft lignin

In this work, the effect of drying temperature (55–130 °C) on the properties of kraft lignin (KL) polymerized with [2-(methacryloyloxy)ethyl] trimethyl ammonium chloride, as a sustainable polymer (KLM) was investigated. KLM exhibited a 3-fold drop in charge density and a 10 % reduction in water solubility. These alterations were found to be associated with both chemical and physical changes determined by NMR and XPS analyses. At 55 °C, chain interactions were predominant due to electrostatic interactions amongst the pMETAC chains with the electronegative atoms present in KL. At 80, 105, and 130 °C drying temperatures, hydrolysis reactions predominated. The KLM polymer possessed, comparatively, a lesser resistance to thermal degradation than KL, and the KLM polymer had a more uniform thermal degradation behavior across the drying temperatures. Glass transition temperature, Tg, was shown to be comparable for KL across the various drying temperatures. KLM, however, showed an increasing trend as drying temperature increased, up to 130 °C, at which point Tg dropped due to KL degradation. Therefore, the drying temperature has a significant impact on the properties of kraft lignin and its cationic polymerized derivative, and it should be carefully selected to minimize the undesired changes in lignin properties.

Uniform boundedness and asymptotic behavior of solutions in a chemotaxis model for alopecia areata

Uniform boundedness and asymptotic behavior of solutions in a chemotaxis model for alopecia areata

Effect of SiCN thin film interlayer for ZnO-based RRAM.

This study investigates the effect of silicon carbon nitride (SiCN) as an interlayer for ZnO-based resistive random access memory (RRAM). SiCN was deposited using plasma-enhanced chemical vapor deposition (PECVD) with controlled carbon content, achieved by varying the partial pressure of tetramethylsilane (4MS). Our results indicate that increasing the carbon concentration enhances the endurance of RRAM devices but reduces the on/off ratio. Devices with SiCN exhibited lower operating voltages and more uniform resistive switching behavior. Oxygen migration from ZnO to SiCN is examined by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses, promoting the formation of conductive filaments (CFs) and lowering set voltages. Additionally, we examined the impact of top electrode oxidation on RRAM performance. The oxidation of the Ti top electrode was found to reduce endurance and increase low resistive state (LRS) resistance, potentially leading to device failure through the formation of an insulating layer between the electrode and resistive switching material. The oxygen storage capability of SiCN was further confirmed through high-temperature stress tests, demonstrating its potential as an oxygen reservoir. Devices with a 20 nm SiCN interlayer showed significantly improved endurance, with over 500 switching cycles, compared to 62 cycles in those with a 5 nm SiCN layer. However, the thicker SiCN layer resulted in a notably lower on/off ratio due to reduced capacitance. These findings suggest that SiCN interlayers can effectively enhance the performance and endurance of ZnO-based RRAM devices by acting as an oxygen reservoir and mitigating the top electrode oxidation effect.

DFT based investigations on inherent CO2 adsorption and direct dissociation capability of Ti2C and Nb2C mxenes

Transition metal carbide MXenes, specifically Ti2C and Nb2C, have been investigated for their ability to efficiently adsorb and dissociate CO2 using First Principles Calculations based on Density Functional Theory (FPS-DFT). Pure Ti2C and Nb2C sheets were studied with the adsorption of 1 to 4 CO2 molecules, and the results were analyzed for each case. For 4 CO2 molecules adsorbed on Ti2C and Nb2C sheets, the weight percentage (wt%) ratio was found to be 21.39% and 14.33%, respectively. The Density of States (DOS) analysis revealed that, upon CO2 adsorption, the CO2 molecule dissociates into CO and O atoms on the MXene surface. The CO molecule showed no significant hybridization with the host sheet atoms, whereas the O atom exhibited strong hybridization with the MXene surface. Transition State (TS) profiles illustrated the dissociation steps on both Ti2C and Nb2C surfaces. Phonon calculations confirmed the dynamic stability of both pure and CO2 adsorbed MXenes. Molecular Dynamics (MD) simulations conducted at 900 K indicated uniform temperature and Mean Square displacement (MSD) profiles, suggesting the stability of both pure and CO2 adsorbed MXenes at elevated temperatures, as well as uniform CO2 adsorption behavior. The adsorption energies for Ti2C and Nb2C sheets were calculated to be in the range of -1.89 to -2.77eV, suggesting that the adsorption process is favorable, spontaneous, and predominantly involves chemisorption. These findings indicate that Ti2C and Nb2C MXenes, in their intrinsic forms, are promising candidates for CO2 adsorption and dissociation technologies.

Comparative studies of the long-term corrosion behavior of Zr-Sn-Fe-Cr-Ni alloys in pure water at 360°C/18.6 MPa with high and low dissolved oxygen content

This study compared the uniform corrosion behavior of Zr-Sn-Fe-Cr-Ni alloys in deionized water at 360°C/18.6 MPa with high and low concentration of dissolved oxygen (DO). It was found that high concentration of DO accelerated the corrosion rate of the Zr-Sn-Fe-Cr-Ni alloys and led to an earlier corrosion transition. Increased DO concentration resulted in a higher content of t-ZrO2 near the metal-oxide interface, which induced greater in-plane compressive stress in the oxide film and a high-level phase transformation from t-ZrO2 to m-ZrO2. This, in turn, led to an earlier occurrence of corrosion transition.

Optimization design and performance study of magnesium alloy vascular clamp

Purpose: This study investigates the effects of varying inner diameter of a vascular clamp made from an Mg–Nd–Zn–Zr alloy on its functional performance. The primary objectives are to optimize the clamp’s structure, assess its performance across different inner diameters, and ultimately determine the optimal configuration. Methods: We developed a V-shaped vascular clamp equipped with a locking mechanism and transverse teeth. The study involved comparing vascular clamps with various inner diameters (0.35 mm, 0.4 mm, 0.5 mm and 0.6 mm, denoted as R0.35, R0.4, R0.5 and R0.6, respectively), achieved by modifying the clamp design. Finite element analysis simulated the closure process of these clamps, both with and without blood vessels, to analyze stress and strain distribution. Subsequently, we manufactured a clamp with the optimized design and conducted performance evaluations, including a closing strength test and an in vitro immersion test. Results: Among the tested vascular clamps, the R0.5 clamp demonstrated the lowest strain (0.50798) and minimal stress on blood vessels (0.7629 MPa). Notably, the R0.5 clamp remained intact during clamping fracture experiments and demonstrated a maximum closing force of 334.98±15.4 mmHg. Regarding corrosion resistance, the clamped position showed a higher corrosion rate (0.179±0.00551 mg.cm-2.day-1) compared to the open clamp (0.161±0.00306 mg.cm-2.day-1). Conclusion: The R0.5 clamp demonstrated superior performance in finite element analysis, showing effective vascular closure, strong clamping force, and uniform corrosion behavior. Overall, these results highlight its potential as an effective tool for vascular closure.

Micromechanical insights for enhancing the rebound resilience of sealing materials based on TPV

Thermoplastic vulcanizate (TPV) with fascinating high elasticity has been received the ongoing research attention in the application of sealing system for the engineering machine. However, there still exists one factor, the plastic strain of plastic matrix adjacent to rubber particles in equatorial direction, which has greatly inhibited the resilience improvement of TPV. Traditional in-situ online experiments could not accurately obtain and quantify the stress-strain evolution behavior of heterogeneous rubber-plastic materials, crucial for resilience. Herein, one kind of TPV based on polyamide thermoplastic elastomer (TPAE) and ethylene-propylene-diene monomer (EPDM) with outstanding rebound resilience has been fabricated via introducing the interfacial compatibilization reaction and reinforcing particles during the melt-reactive blending. One three-dimensional representative volume element (3D-RVE) model has been established to analyze the deformation mechanism of such designed TPV in this work compared with that for TPV based on polypropylene (PP) and EPDM. By analyzing the forces on the RVE mesh units, it could reveal that the TPAE matrix exhibited more uniform stress transfer behavior at the thin ligament, and the recovery behavior of TPV matrix mainly occurred at the thin ligament. This work would provide important value for the preparation of new high elastic TPV materials from a microscopic level.

The interpretation of null and overt subject pronouns in Spanish compared to Greek and Italian

In recent years, several studies have suggested that Null Subject Languages (NSLs) do not exhibit uniform behaviour in all respects. This paper aims to determine whether the interpretation of null and overt subject pronouns in Spanish differs from that in two other NSLs: Italian and Greek. To this end, we replicated the sentence interpretation experiment conducted by Torregrossa et al. (2020) on Greek and Italian to obtain a fully comparable set of data.The results indicate that Spanish differs significantly from both Italian and Greek in the interpretation of null and overt pronouns. Spanish participants accept null subjects referring to both subject and object antecedents to the same extent. The same pattern is observed for overt subject pronouns. To explain the observed differences, we propose that two properties of its grammar influence the interpretation of null subjects and overt pronouns in Spanish: i) a flexible word order, allowing for SVO, VSO, and VOS; and ii) the existence of differential object marking (DOM). We hypothesise that these two factors may affect antecedent selection, thereby partially accounting for the differences observed among the languages under consideration.

Covalent Triazine Based Frameworks with Donor‐Donor‐π‐Acceptor Structures for Dendrite‐Free Lithium Metal Batteries

AbstractThe appearance of disordered lithium dendrites and fragile solid electrolyte interfaces (SEI) significantly hinder the serviceability of lithium metal batteries. Herein, guided by theoretical predictions, a multi‐component covalent triazine framework with partially electronegative channels (4C‐TA0.5TF0.5‐CTF) is incorporated as a protective layer to modulate the interface stability of the lithium metal batteries. Notably, the 4C‐TA0.5TF0.5‐CTF with optimized electronic structure at the molecular level by fine‐tuning the local acceptor‐donor functionalities not only enhances the intermolecular interaction thereby providing larger dipole moment and improved crystallinity and mechanical stress, but also facilitates the beneficial effect of lithiophilic sites (C−F bonds, triazine cores, C=N linkages and aromatic rings) to further regulate the migration of Li+ and achieve a uniform lithium deposition behavior as determined by various in‐depth in/ex situ characterizations. Due to the synergistic effect of multi‐component organic functionalities, the 4C‐TA0.5TF0.5‐CTF modified full cells perform significantly better than the common two/three‐component 2C‐TA‐CTF and 3C‐TF‐CTF electrodes, delivering an excellent capacity of 116.3 mAh g−1 (capacity retention ratio: 86.8 %) after 1000 cycles at 5 C and improved rate capability. This work lays a platform for the prospective molecular design of improved organic framework relative artificial SEI for highly stable lithium metal batteries.

Uniform Stabilization and Asymptotic Behavior with a Lower Bound of the Maximal Existence Time of a Coupled System’s Semi-Linear Pseudo-Parabolic Equations

Uniform Stabilization and Asymptotic Behavior with a Lower Bound of the Maximal Existence Time of a Coupled System’s Semi-Linear Pseudo-Parabolic Equations

Organic heterojunction memristors with enhanced tunable resistive states for artificial synapses

Tunable and uniform evolution of conductance is the key performance metric for neuromorphic computing leveraging memristors. Nonetheless, the stochastic conductance update associated with limited material composition and uncontrollable filament distribution has restricted the tunability that can be customized for targeted synaptic properties. Here, we introduce organic heterojunction memristors utilizing the C60/P3HT bilayer, demonstrating analog switching characteristics with multilevel conductance states. We demonstrate that both conventional bipolar and unipolar voltages can achieve synaptic plasticity modulation for potentiation and depression, offering enhanced tunability. Through in situ Raman spectroscopy and impedance spectroscopy, we directly observe the dynamic alterations within the active layers during switching processes. The reversible migration of ions diminishes the barrier within the polymer layer, leading to highly uniform resistive switching behavior. The C60 layer functions as a confined transport medium, mitigating critical current variability issues. Moreover, we introduce a shunt resistor approach, furnishing analog memristors with selectively adjustable uniformity, enhanced linearity, and expanded dynamic conductance range, providing a general solution adaptable to various memristive hardware architectures.

Synthesis, structure, supramolecular assembly inspection by Hirshfeld surface analysis, DFT study and molecular docking inspection of 4,5-bis(2-chlorophenyl)-8a-phenylhexahydropyrimido[4,5-d]pyrimidine-2,7(1H,3H)-dithione

We studied the three-component condensation of 2-chloraldehyde, acetophenone, and thiourea in conjunction with HCl, resulting in the formation of a new compound: 4,5-bis(2-chlorophenyl)-8a-phenylhexahydropyrimido[4,5-d]pyrimidine-2,7(1H,3H)-dithione (CPPD). The compound's structure was affirmed via X-ray diffraction study. The asymmetric unit contained two molecules that were independent relative to crystallography and an ethanol solvent. The difference between independent molecules was explored by dihedral angles between similar rings in both molecular. The difference between molecules was further explored by molecular overlay plot. The supramolecular assembly was supported via diverse intermolecular interactions which were studied through the use of Hirshfeld surface analysis. Electronic structure computations were carried out at the ωb97xd/tzvp level. Natural bonding orbital (NBO), and FMO study reveal reactivity and charge transfer mechanisms within the compound. Furthermore, the nature of bonding in the present molecule is characterized through quantum theory of atoms in molecules (QTAIM), ELF, and LOL studies. Ab-initio molecular dynamic (AIMD) revealed the kinetic and thermodynamic stability at 300 K. The DFT results have excellent correlation with experimental data. The molecular docking and molecular dynamics simulation further revealed the compound to get deep access in the active pocket of type 2 anti-diabetes GLUT4 protein. This was validated by the stable dynamics as demonstrated by the uniform behavior of the root mean square deviation (RMSD) plot. The root mean square fluctuation (RMSF) also showed stable interactions with amino acids in the presence of the compound. Further, simulation trajectories on the basis of binding free energies indicate the significant role of van der Waals force in the formation of the intermolecular docked complex. This concluded the compound might be a potent structure for the development of anti-diabetic compounds.

Pre-structural patterning approach for enhancing flow characteristics of B-stage film-type epoxy molding compound

Epoxy molding compound (EMC) compositions of silica powder and epoxy matrix have been utilized as encapsulation for semiconductor packaging over the past decades. Among various forms of EMC, film-type EMC offers untapped potential. Utilizing EMC film as an encapsulation material allows larger and more uniform encapsulation behavior especially for panel-level and wafer-level packaging applications. In material aspects, as increases silica contents in EMC film, it can encounter a trade-off relationship between the coefficient of thermal expansion (CTE) and the material's viscosity. As silica content increases, the CTE tends to decrease, which enhances warpage behavior. However, viscosity also tends to increase, which reduces flowability. To overcome these tradeoff relationships, in our study, we have demonstrated a pre-structural patterning approach to enhance flowability of B-stage EMC film without changing the raw compositions of material. By doing that, we can suppose increased flowability of film while having similar thermomechanical properties. For patterning while maintaining B-stage, patterned protection film was fabricated using a brass-based metallic mold and a PDMS/PUA-based soft mold. Subsequently, pre-structural patterned EMC was fabricated by transferring the patterned protection film onto a B-stage EMC film using a laminator. The effectiveness of patterning on EMC film was investigated in both numerical and experimental molding analysis according to rheological, chemical, and thermomechanical characterization. The pre-structural patterning approach demonstrated enhanced flow characteristics via a shortened flow path despite the increased viscosity caused by higher silica content.

Design and development of the additively manufactured Zn-Li scaffolds for posterolateral lumbar fusion

Spinal fusion is a commonly used technique to treat acute and chronic spinal diseases by fusion of the adjacent vertebrae, aiming at achieving stability and eliminating the mobility of the objective segment. While bone autografts and allografts have been conventionally used for spinal fusion, limitations persist in achieving optimization of both good osteoinductive capacity and mechanical stability. In this study, additively manufactured Zn-Li scaffolds were developed and evaluated for their potential in spinal fusion. First, three scaffold structures (BCC, Diamond, and Gyroid) were designed and verified in vitro. Due to the smooth transition surfaces and uniform degradation behavior, the Gyroid Zn-Li scaffold demonstrated mechanical integrity during degradation and enhanced cellular proliferation compared to the other two scaffolds. Subsequently, Zn-Li scaffolds (Gyroid) were selected for posterolateral lumbar fusion (L4/L5) in rabbits. Following 12 weeks of implantation, the Zn-Li scaffolds demonstrated a moderate biodegradation rate and satisfactory biocompatibility. Compared to bone allografts, the Zn-Li scaffolds significantly improved osseointegration adjacent to the transverse processes, which led to enhanced segmental stability of the fused vertebrae post posterolateral lumbar fusion. Overall, the results show that the biodegradable Zn-Li scaffold holds substantial potential as the next-generation graft for spinal fusion.

Covalent Triazine Based Frameworks with Donor-Donor-π-Acceptor Structures for Dendrite-Free Lithium Metal Batteries.

The appearance of disordered lithium dendrites and fragile solid electrolyte interfaces (SEI) significantly hinder the serviceability of lithium metal batteries. Herein, guided by theoretical predictions, a multi-component covalent triazine framework with partially electronegative channels (4C-TA0.5TF0.5-CTF) is incorporated as a protective layer to modulate the interface stability of the lithium metal batteries. Notably, the 4C-TA0.5TF0.5-CTF with optimized electronic structure at the molecular level by fine-tuning the local acceptor-donor functionalities not only enhances the intermolecular interaction thereby providing larger dipole moment and improved crystallinity and mechanical stress, but also facilitates the beneficial effect of lithiophilic sites (C-F bonds, triazine cores, C=N linkages and aromatic rings) to further regulate the migration of Li+ and achieve a uniform lithium deposition behavior as determined by various in-depth in/ex situ characterizations. Due to the synergistic effect of multi-component organic functionalities, the 4C-TA0.5TF0.5-CTF modified full cells perform significantly better than the common two/three-component 2C-TA-CTF and 3C-TF-CTF electrodes, delivering an excellent capacity of 116.3 mAh g-1 (capacity retention ratio: 86.8 %) after 1000 cycles at 5 C and improved rate capability. This work lays a platform for the prospective molecular design of improved organic framework relative artificial SEI for highly stable lithium metal batteries.

Secondary voltage regulation based on full-state feedback — performance assessment with Dyna[formula omitted]o

This paper discusses the performance assessment of new secondary voltage regulators currently under study in France to address challenges posed by the energy transition. With renewable integration and increasing cross-border interconnections, power flow variations surge across the network. Coupled with the historical SVRs’ relatively slow response, operational since the late 1970s, recent observations show higher voltage volatility. Prior research has already highlighted the potential of two novel regulators: the Average Q-SVR and the LQ-SVR, in mitigating these issues. Our focus here centres on the latter and begins by discussing the implications of control design hypotheses on closed-loop system performance. These include linearisation, neglecting communication delays, and assuming uniform dynamic behaviour across all resources. We then propose a two-step control design, leveraging Linear Quadratic Regulator (LQR) and eigenstructure placement methods and demonstrate that this approach surpasses the LQR method alone in terms of transient reactive power tracking.

Biocompatibility and osteoinductivity of biodegradable Zn-Li-Ca ternary alloys for bone regeneration: In vitro and in vivo studies

Bone defects caused by trauma, fracture-related infection, congenital malformations, and tumor resection remain significant challenges to human health. Biodegradable Zn-based alloys have been acknowledged for their outstanding comprehensive properties in addressing bone defects, offering adequate mechanical support, mild degradation rate, and satisfactory biosafety. In this study, Zn–0.8Li-0.1Ca alloy was fabricated and comprehensively evaluated both in vitro and in vivo for their properties. The Zn-0.8Li-0.1Ca alloy demonstrated an ultimate tensile strength of 251.07 ± 9.59 MPa and an elongation of 18.89 ± 1.26 %. Electrochemical and in vitro degradation tests showed that there was a mild degradation rate (21.94 ± 2.26 μm/year) and uniform degradation behavior in the Zn-0.8Li-0.1Ca alloy. Real-time PCR analysis revealed that the Zn-0.8Li-0.1Ca alloy effectively upregulated the expression levels of osteogenesis-related genes (ALP, COL-1, OCN, and RUNX-2). Micro-CT and histological evaluations demonstrated that bone regeneration within the Zn-0.8Li-0.1Ca alloy scaffold was significantly superior to that of pure Ti in repairing rat femoral condyle defects. Therefore, the biodegradable Zn-0.8Li-0.1Ca ternary alloy displayed satisfactory mechanical properties, degradation behavior, biocompatibility, and osteogenic activity, positioning it as a promising candidate for bone repair treatment.

Promoting Li2S Nucleation/Dissolution Kinetics via Multiple Active Sites over TiVCrMoC3Tx Interface.

Lithium-sulfur batteries (LSBs) are still limited by some issues such as polysulfides shuttle and lithium dendrites. Recently, the concept "high-entropy" has been considered as the research hotspot and international frontier. Herein, a high entropy MXene (TiVCrMoC3Tx, HE-MXene) doped graphene is designed as the modified coating on commercial separators for LSBs. The HE-MXene affords multiple metal active sites, fast Li+ diffusion rate, and efficient adsorption toward polysulfide intermediates. Furthermore, strong lithophilic property is favorable for uniform Li+ deposition. The combination of in situ characterizations confirms TiVCrMoC3Tx effectively promotes the Li2S nucleation/dissolution kinetics, reduces the Li+ diffusion barrier, and exhibits favorable lithium uniform deposition behavior. This TiVCrMoC3Tx/G@PP provides a high-capacity retention rate after 1000 cycles at 1 C and 2 C, with a capacity decay rate of merely 0.021% and 0.022% per cycle. Surprisingly, the cell operates at a low potential of 48mV while maintaining at 5mA cm-2/5 mAh cm-2 for 4000h. Furthermore, it still maintains a high-capacity retention rate under a high sulfur loading of 4.8/6.4mg cm-2 and a low E/S ratio of 8.6/7.5µgmL-1. This work reveals a technical roadmap for simultaneously addressing the cathode and anode challenge, thus achieving potential commercially viable LSBs.

Accuracy of hygro-expansive curl predictions for paper sheets based on homogenised 2D and 3D network representations

Paper, a porous-fibrous network, is made up of hydrophilic fibres, which are notably susceptible to deformations due to variations in moisture content. The response of paper sheets to full or partial wetting, based on the water-induced fibre swelling, has mostly been predicted in the past using highly idealised two-dimensional network geometries. The purpose of the present paper is to establish how precisely the two-stage process of determining effective hygro-expansivity under uniform wetting by a two-dimensional model followed by bending analysis using a continuum model predicts the curl of a fully three-dimensional network. In the present multi-scale modelling work, the moisture-induced homogenised sheet scale curl, derived from hygro-elastic deformations using non-uniform moisture profiles, is analysed based on an idealised non-woven three-dimensional fibrous network finite element model. First, the effective paper sheet swelling properties, derived computationally for the uniform wetting condition, are compared with analytically homogenised hygro-elastic properties. Whereas the analytically predicted elastic modulus has an inaccuracy of only ∼5%, the hygro-expansivity coefficient is over-predicted by roughly a third for a network with straight fibres. The difference is smaller if waviness of the fibres and wrap-around in the fibre bonds are taken into account. Fibre alignment turns out to have little influence. Subsequently, paper sheet curl predictions made by the analytical model are compared with that computed from the three-dimensional network model. The inaccuracy of the fully analytical model, based on the two-dimensional network description, relative to the fully detailed three-dimensional computational model with straight fibres is on the order of 40%–50%. The fidelity of the simple model is primarily constrained by the inaccuracy of the effective hygro-expansion coefficient. If the expansivity extracted from the three-dimensional simulations under uniform wetting is inserted, the inaccuracy drops to less than 10%. The continuum bending description hence performs adequately, provided it is based on a reliable estimation of the uniform expansion behaviour of the material.