Material Loading Research Articles

Clarifying the limiting factor of material utilization in thick electrodes of lithium-ion batteries

Improving the energy density of lithium-ion batteries is a goal pursued in state-of-the-art batteries, and the use of thick electrodes with high active material loading densities is one of the most effective and direct methods. Most studies indicate that the hindrance to the practical application of thick electrodes is mainly attributed to the slow charge kinetics, resulting in very low utilization of active materials. Here, this work shows that the thermodynamic properties of the electrode material also have a significant impact on the electrode reaction behavior. When the equilibrium potential of the electrode material has a strong dependence on the state of charge, it promotes the uniform reaction of the electrode active material. By simulating the full battery under low and high load conditions, the reaction behavior of the thin electrodes is dominated by the equilibrium potential curve. However, the reaction behavior of thick electrodes is regulated by both kinetics and thermodynamics and depends on the strength of the relationship between these two properties. Meanwhile, the graphite anode limits the release of the full battery capacity to a greater extent. This work points out a new direction for the practical development and application of thick electrodes.

Development Of Digital-Based Classroom Learning E-Learning Web Interface Study Bumigora University Project Case

Bumigora University has been trusted as a campus that can develop interactive learning models based on free open source software for all teaching and learning activities related to computers at Bumigora University. One of the obstacles that arises is doing full-day learning (8 hours) there is limited time and the material load is quite dense so a breakthrough learning model is needed that gives rise to acceleration and ease of transferring knowledge from learning sources (lecturers, textbooks, and other learning resources) to student. Therefore, Bumigora University designed an application in the form of a website where in this application admins and teachers can carry out management processes on student data and can convey information and materials or assignments to students. Students can see information about teaching and learning activities and can see subjects, materials, and grades. You can also download materials. From the results of testing using the Black Box Testing method that has been carried out, it can be concluded that the Bumigora University E-Learning System has fulfilled the research objectives to be used properly, as evidenced by the functioning of the functions in the application properly.

Implementation of Legendre wavelet method for the size dependent bending analysis of nano beam resonator under nonlocal strain gradient theory

The bending analysis due to thermoelastic loading in nanoscale materials is primarily determined by the physical aspect of the material and the modeling of structures. This paper examines the prediction of bending characteristics of the Euler-Bernoulli beam using Moore-Gibson-Thompson (MGT) thermoelasticity theory in conjunction with nonlocal strain gradient theory (NSGT). The coupled equations for dimensionless deflection and temperature change with ramp-type heating boundary conditions are formulated and solved using the Laplace transform method and the wavelet approximation method. The stiffness softening and hardening effects due to nonlocal and length-scale parameters are assessed, and their discrepancies are discussed. Findings further reveal that the impact of the thermal relaxation parameter on deflection and temperature is negligible. Moreover, the different aspect ratios of the beam's structure depict the prominently behavior of structural simulations in bending.

Direct spatio-temporal stress field determination combining full-field deformation measurements and explicit finite element method: Concept verification

High strain rate loading of materials with spatially heterogeneous properties produces non-homogeneous and transient stress-strain states. Such stress-strain states are atypical of classical split Hopkinson pressure bar (SHPB) analysis that assumes homogeneous deformation and dynamic force equilibrium. To determine spatio-temporal stress fields in heterogeneous materials, a novel concept combining digital image correlation (DIC) full-field deformation measurements and explicit dynamic finite element method (EFEM) is described in this paper. The concept utilizes measured boundary forces and DIC measurements including both displacements and accelerations as input. The measured input is used to calculate internal forces, and hence the stress fields, within each continuum finite element by solving the governing equations of motion using the framework of EFEM. The DIC+EFEM concept procedure is verified using simulated synthetic data considering one-dimensional stress wave propagation in a bar. The reconstructed axial stress fields match identically with the exact EFEM solution for both homogeneous and heterogeneous materials that are elastic or elastic-plastic. The influence of DIC measurement noise on the reconstructed stresses is also studied.

Simultaneous nitrate and phosphorus removal in novel steel slag biofilters: Optimization and mechanism study

The simultaneous nitrate (NO3−-N) and phosphorus (P) removal systems are considered to be an effective wastewater treatment technology. However, so far, there are few studies on system optimization to improve NO3−-N and P removal. In this study, nine simultaneous NO3−-N and P removal biofilters (SNPBs) were constructed to treat simulated wastewater. In order to optimize the NO3−-N and P removal, different material loading positions were set: (1) red soil, steel slag, and rice straw (RSR), (2) steel slag, red soil, and rice straw (SRR), and (3) red soil, rice straw, and steel slag (RRS). Results showed that the above three treatments had mean removal efficiencies of 58%–91% for NO3−-N and 55%–81% for TP, with the best N and P removal occurring in the SRR. The TN mass balance indicated that microbial removal was responsible for 78.2% of the influent TN in the SRR biofilter. The key microorganisms were Enterobacter, Klebsiella, Pseudomonas, Diaphorobacter, and unclassified_f_Enterobacteriaceae, which accounted for 61.9% of the total microorganisms. The main P-removal mechanism was the formation of Al–P, Fe–P, and Ca–P in red soil or steel slag layer. In addition, the decrease of SRR effluent pH from 11.86 in 1–7 days to 7.75 in 8–50 days indicated that red soil and rice straw had a synergistic effect on water pH reduction. These results suggest that a reasonable combination of steel slag with red soil and rice straw not only simultaneously removes NO3−-N and P but also additionally solves the problem of high pH caused by steel slag.

Three-Phase Transformer Optimization Based on the Multi-Objective Particle Swarm Optimization and Non-Dominated Sorting Genetic Algorithm-3 Hybrid Algorithm

The performance of transformers directly determines the reliability, stability, and economy of the power system. The methodologies of minimizing the transformer manufacturing cost under the premise of ensuring performance is of great significance. This paper presented an innovative multi-objective optimization model to analyze the relationship between design parameters and transformer indicators. In addition, the sensitive analysis is conducted to exploit the interaction relationships between design parameters and targets. The reliability of the model was demonstrated in 50 MVA/110 kV and 63 MVA/110 kV prototypes, compared with the actual material usage, short-circuit impedance, and load loss, and the maximum error is less than 7%. Due to this problem having many optimization objectives and the high dimension of variables, a two-stage algorithm called MOPSO-NSGA3 (multi-objective particle swarm optimization and non-dominated sorting genetic algorithm-3) is presented. MOPSO is used to find non-domain solutions within the search space in the first stage, and the solution will be used as prior knowledge to initialize the population in NSGA3. The result shows that this algorithm can be effectively used in multi-objective optimization tasks and best meets the requirements of transformer designs that minimize the short-circuit deviation, operating loss, and manufacturing costs.

Nonlinear two-dimensional transient thermoelastic analysis of functionally graded composite plates subjected to localised cooling loads

In this study, for the first time, localized thermal cooling is considered for the transient thermoelastic response of an axisymmetric plate, addressing the underexplored area of localized low-temperature thermoelasticity. Functionally graded composite plates are analyzed which consist of a mixture of stainless steel (SUS304) and low-carbon steel (AISI1020). A two-dimensional transient heat conduction equation is employed to capture localized cooling effects, featuring various adaptive time-dependent thermal boundary conditions which mirror both loading and unloading scenarios, effectively simulating real-world phenomena. Novel parameters are introduced to facilitate a comprehensive understanding of various aspects of thermal load handling and their impact on thermoelastic responses. The heat conduction equations are solved using the Generalized Differential Quadrature Method (GDQM) and the Crank-Nicolson scheme. The nonlinear governing equations, incorporating geometrical nonlinearity through the von Kármán assumption within the First Shear Deformation Theory (FSDT) framework, are solved using the GDQM and the Picard's technique. The model is validated using Finite Element Method (FEM) through Abaqus. A comprehensive analysis is provided that considers influence of the ratio of thermally affected and unaffected plate surface, thermal load magnitude, rapidity of thermal loading and unloading, duration of the cooling load, geometrical nonlinearity, and temperature dependence of material. The study shows that the maximum von Mises stress within the structure remains consistent regardless of the duration of the cooling load, as long as the rate at which the cooling load is applied stays the same. Additionally, the findings reveal that even minor localized thermal loads can produce substantial stress, especially at the intersection of thermally affected and non-affected zones on the exposed surface in some situations.

Self‐Assembled Lithiophilic Interface with Abundant Nickel‐Bis(Dithiolene) Sites Enabling Highly Durable and Dendrite‐Free Lithium Metal Batteries

AbstractDespite its ultrahigh theoretical capacity and ultralow redox electrochemical potential, the practical application of lithium metal anodes is still hampered by severe dendrite growth and unstable solid electrolyte interphase (SEI). Herein, a self‐assembled lithiophilic interface (SALI) for regulating Li electroplating behavior is constructed by introducing a meticulously synthesized Ni‐bis(dithiolene)‐based molecule (NiS4‐COOH) into a hybrid fluorinated ester‐ether electrolyte. The NiS4‐COOH molecules with carboxyl functional groups can spontaneously anchor on the Li metal surface to form a SALI, whose abundant Ni‐bis(dithiolene) sites can effectively reduce the initial Li deposition overpotential and guide the subsequent uniform Li electrodeposition. Moreover, due to the interaction between the coordination unsaturated Ni atom and the negatively charged PF6−, the NiS4‐COOH additive can significantly change the ionic coordination environment in the electrolyte, which is greatly conducive to suppressing PF6− decomposition, optimizing SEI composition and accelerating Li‐ion transfer. Consequently, the NiS4‐COOH‐modified electrolyte leads to impressive electrochemical performance of Li||LiFePO4 and Li||LiNi0.8Co0.1Mn0.1O2 batteries, delivering ultrahigh Coulombic efficiencies, considerable capacity retention, and good rate performance even at high areal active material loadings. This study presents the great potential of SALIs derived from multifunctional metal‐organic hybrid electrolyte additives toward high‐specific‐energy Li metal batteries.

In situ measurement of damage evolution in shocked magnesium as a function of microstructure

Accurate modeling and prediction of damage induced by dynamic loading in materials have long proved to be a difficult task. Examination of postmortem recovered samples cannot capture the time-dependent evolution of void nucleation and growth, and attempts at analytical models are hindered by the necessity to make simplifying assumptions, because of the lack of high-resolution, in situ, time-resolved experimental data. We use absorption contrast imaging to directly image the time evolution of spall damage in metals at ∼1.6-μm spatial resolution. We observe a dependence of void distribution and size on time and microstructure. The insights gained from these data can be used to validate and improve dynamic damage prediction models, which have the potential to lead to the design of superior damage-resistant materials.

Machine learning-based probabilistic fatigue assessment of turbine bladed disks under multisource uncertainties

PurposeThe multisource uncertainties, including material dispersion, load fluctuation and geometrical tolerance, have crucial effects on fatigue performance of turbine bladed disks. In view of the aim of this paper, it is essential to develop an advanced approach to efficiently quantify their influences and evaluate the fatigue life of turbine bladed disks.Design/methodology/approachIn this study, a novel combined machine learning strategy is performed to fatigue assessment of turbine bladed disks. Proposed model consists of two modeling phases in terms of response surface method (RSM) and support vector regression (SVR), namely RSM-SVR. Two different input sets obtained from basic variables were used as the inputs of RSM, then the predicted results by RSM in first phase is used as inputs of SVR model by using a group data-handling strategy. By this way, the nonlinear flexibility of SVR inputs is improved and RSM-SVR model presents the high-tendency and efficiency characteristics.FindingsThe accuracy and tendency of the RSM-SVR model, applied to the fatigue life estimation of turbine bladed disks, are validated. The results indicate that the proposed model is capable of accurately simulating the nonlinear response of turbine bladed disks under multisource uncertainties, and SVR-RSM model provides an accurate prediction strategy compared to RSM and SVR for fatigue analysis of complex structures.Originality/valueThe results indicate that the proposed model is capable of accurately simulate the nonlinear response of turbine bladed disks under multisource uncertainties, and SVR-RSM model provides an accurate prediction compared to RSM and SVRE for fatigue analysis of turbine bladed disk.

Equivalent in-plane elastic moduli of honeycomb materials under hypergravity conditions

Honeycomb materials frequently encounter hypergravity conditions in both aerospace and biological contexts during phases such as launch, reentry or under centrifugal motion. The significant body force engendered by hypergravity induces alterations in the microstructure of honeycomb materials, which in turn, influences their macroscopic mechanical behaviour. Leveraging the stiffness of the beam element as a pivotal variable, we successfully derived the equivalent moduli of the honeycomb material under hypergravity conditions. We further proposed the concept of a ‘hypergravity factor’, elucidating that the density of the base material, the dimensions of honeycomb cells and the magnitude of the hypergravity contribute to amplifying hypergravity effects. The results, numerically validated through finite-element simulations, could be reduced to the case that neglects body force. The critical buckling load of the honeycomb material under hypergravity can be assessed by setting the derived moduli to zero. In the presence of hypergravity, a honeycomb material undergoes a transition into a gradient material along the hypergravity direction, thereby exacerbating anisotropy. This phenomenon is theoretically expected to occur in virtually all porous materials. The analytical framework adopted, which employs beam stiffness as an intermediary variable, facilitates the extension of these results to honeycomb materials which encompass beam elements with functional gradients or varying cross-sectional morphologies.

Fabrication of a 3D structure MnO2 electrode with high MnO2 mass loading as the cathode for high-performance aqueous zinc-ion batteries

Benefiting from the remarkable advantages (eco-friendly, cost-effective, and high safety) of rechargeable aqueous zinc-ion batteries (AZIBs), AZIBs are regarded as viable alternatives to traditional Lithium-ion batteries (LIBs). However, in prevailing research, the excellent electrochemical performance usually achieved by ultra-low active material loadings (e.g., <1 mg/cm²), which is far from the active material mass loading of commercial electrodes in practical (≥10 mg/cm²). Balancing superior properties with high mass loading has posed a challenge. To surmount this, an innovative method combined ultrasonic processing, freeze-drying, and 3D printing technologies is used to engineer a high MnO2 mass loading cathode for AZIBs (3D cathode). Notably, the grid structure of 3D cathode substantially augmenting the surface area for redox reactions during charge/discharge processes, which greatly enhanced the pseudo-capacitance process of cathode. Additionally, the uniform and stable microstructure exhibited the dual capability of expediting ion/electron transfer and sustaining the structural integrity throughout charge/discharge cycles. Consequently, the 3D cathode demonstrated superior comprehensive electrochemical properties at the MnO2 high mass loading of 10 mg/cm2 (138.7 mAh/g at 1 A/g, 87.4 mAh/g after 500 cycles, 82 % energy efficiency) and 15 mg/cm2 (113.3 mAh/g at 1 A/g, 56.3 mAh/g after 400 cycles, 81 % energy efficiency).

Eugenol-Based Polymeric Materials-Antibacterial Activity and Applications.

Eugenol (4-Allyl-2-methoxy phenol) (EUG) is a plant-derived allyl chain-substituted guaiacol, widely known for its antimicrobial and anesthetic properties, as well as the ability to scavenge reactive oxygen species. It is typically used as a mixture with zinc oxide (ZOE) for the preparation of restorative tooth fillings and treatment of root canal infections. However, the high volatility of this insoluble-in-water component of natural essential oils can be an obstacle to its wider application. Moreover, molecular eugenol can be allergenic and even toxic if taken orally in high doses for long periods of time. Therefore, a growing interest in eugenol loading in polymeric materials (including the encapsulation of molecular eugenol and polymerization of EUG-derived monomers) has been noted recently. Such active macromolecular systems enhance the stability of eugenol action and potentially provide prolonged contact with pathogens without the undesired side effects of free EUG. In this review, we present an overview of methods leading to the formation of macromolecular derivatives of eugenol as well as the latest developments and further perspectives in their pharmacological and antimicrobial applications.

Dynamics of Spinning Viscoelastic Tapered Shafts with Axial Motion

In this paper, the vibration and stability of spinning viscoelastic tapered shafts with axial motion are investigated. The model of the shaft system is developed by incorporating the spinning motion, axial motion, axial load, viscoelasticity, and geometric properties. The coupled governing equations of motion of the spinning shaft system are obtained by applying Hamilton’s principle. By employing the Laplace transform and Galerkin discretization method, the natural frequency and modal damping are computed. Also, the critical divergence axial and spinning velocities, as well as the flutter axial velocity, are determined. As a result, the divergence and flutter instability conditions of the system are examined. The effects of the main parameters, such as taper ratio, axial load, and viscoelasticity of material, on the vibration behavior of the shaft system are evaluated. The results show that compared to the homogeneous spinning shaft system with uniform cross-section, the vibration and stability of the viscoelastic tapered shaft system undergo an essential evolution. It is further demonstrated that the axial load and viscoelasticity are also the key parameters governing the stability of the system.

NiCo2O4 on monolithic 3DGF/CNT for high performance hybrid zinc batteries

Hybrid Zn-Air and Zn-MX (MX refers to metal species with cation redox properties) batteries that combine the merits of both types are attracting increasing interest. However, the low areal capacity of the Zn-MX segment hinders their applications toward power resilience. Increasing the electrochemically active material loading is critical to achieving sufficient capacity but poses a challenge for conventional electrodes to maintain fast gas diffusion, which is necessary for the Zn-air function. Herein, we report an advanced, monolithic, carbon-based current collector by growing carbon nanotubes (CNT) onto a 3D graphene network (3DGF). The porous and highly conductive current collector readily accommodates more electrochemically active material, NiCo2O4 (NCO), thereby improving the Zn-NCO segment’s capacity without sacrificing the Zn-air segment’s performance. The 3DGF/CNT/NCO electrode was fabricated into a hybrid Zn battery which achieved a superior areal specific capacity of 2.87 mAh cm−2 at 5 mA cm−2, almost threefold of previously reported values, and an impressive rate capability and cycling stability with 98% of original capacity retained after 1000 cycles at 20 mA cm−2 charging/discharging current density. This work showcases 3DGF/CNT as an advanced current collector architecture for new and novel batteries.

Modeling of a screw extruder 3D printer using pellets or crushed polymer waste as the raw material

In this article, the process of moving polymer material in the screw extruder of a 3D printer, which uses granules or crushed polymer waste as raw materials, is chosen as the object of mathematical modeling. It is noted that the modeling of screw extruders is a highly relevant task, as it is an essential tool for optimizing production processes in the polymer industry and other industries where they are used. It allows you to study and optimize the material cylinder's processes thoroughly. It is noted that the modeling of screw extruders for 3D printers, which use granules or shredded plastic waste, is a critical factor in supporting innovation, increasing production efficiency, improving product quality, and developing new technological solutions in various industries. It was noted that during the movement of the material along the channel of the extruder screw, several of its states continuously changed from a solid at the entrance of the channel to a viscous liquid at the exit. In the feed zone, the polymer is solid and moves along the material cylinder due to friction. A physical model was used in the simulation, in which compacted polymer particles do not move relative to each other during movement through the channel. This is because the internal friction forces in the polymer greatly outweigh the friction of the polymer on the steel, and the particles move as a single elastic compressible medium due to the balance of dry friction between the cylinder wall and the screw. The geometrical parameters of the extruder in the feed zone are shown. A diagram of the expanded extruder channel for calculating productivity is given. A diagram of the movement of material in it was drawn up to determine the productivity of the extruder feed zone. A mathematical model of productivity was obtained depending on the diameter of the screw, the frequency of rotation, the depth of the screw channel, and the angle of elevation of the screw line of the screw cutting. The pressure in the extruder channel was calculated. A scheme for calculating the forces acting on the material in the feeding zone is given. A formula was obtained for determining the pressure in the material loading zone from the hopper, which connects the characteristics of the polymer material and the geometric parameters of the loading hopper. Keywords: 3D printer, screw extruder, modeling; polymer material; loading area; bunker; productivity; pressure.

Rational Integration of SnMOF/SnO2 Hybrid on TiO2 Nanotube Arrays: An Effective Strategy for Accelerating Formaldehyde Sensing Performance at Room Temperature.

Formaldehyde is ubiquitously found in the environment, meaning that real-time monitoring of formaldehyde, particularly indoors, can have a significant impact on human health. However, the performance of commercially available interdigital electrode-based sensors is a compromise between active material loading and steric hindrance. In this work, a spaced TiO2 nanotube array (NTA) was exploited as a scaffold and electron collector in a formaldehyde sensor for the first time. A Sn-based metal-organic framework was successfully decorated on the inside and outside of TiO2 nanotube walls by a facile solvothermal decoration strategy. This was followed by regulated calcination, which successfully integrated the preconcentration effect of a porous Sn-based metal-organic framework (SnMOF) structure and highly active SnO2 nanocrystals into the spaced TiO2 NTA to form a Schottky heterojunction-type gas sensor. This SnMOF/SnO2@TiO2 NTA sensor achieved a high room-temperature formaldehyde response (1.7 at 6 ppm) with a fast response (4.0 s) and recovery (2.5 s) times. This work provides a new platform for preparing alternatives to interdigital electrode-based sensors and offers an effective strategy for achieving target preconcentrations for gas sensing processes. The as-prepared SnMOF/SnO2@TiO2 NTA sensor demonstrated excellent sensitivity, stability, reproducibility, flexibility, and convenience, showing excellent potential as a miniaturized device for medical diagnosis, environmental monitoring, and other intelligent sensing systems.

Investigation of Material Loading on an Evolved Antecedent Hexagonal CSRR-Loaded Electrically Small Antenna.

Recent advances in embedded antenna and sensor technologies for 5G communications have galvanized a response toward the investigation of their electromagnetic performance for urban contexts and civil engineering applications. This article quantitatively investigates the effects of material loading on an evolved antecedent hexagonal complementary split-ring resonator (CSRR)-loaded antenna design through simulation and experimentation. Optimization of the narrowband antenna system was first performed in a simulation environment to achieve resonance at 3.50 GHz, featuring an impedance bandwidth of 1.57% with maximum return loss and theoretical gain values of 20.0 dB and 1.80 dBi, respectively. As a proof-of-concept, a physical prototype is fabricated on a printed circuit board followed by a simulation-based parametric study involving antenna prototypes embedded into Ordinary Portland Cement pastes with varying weight percentages of iron(III) oxide inclusions. Simulation-derived and experimental results are mutually verified, achieving a systemic downward shift in resonant frequency and corresponding variations in impedance matching induced by changes in loading reactance. Finally, an inversion modeling procedure is employed using perturbation theory to extrapolate the relative permittivity of the dielectric loaded materials. Our proposed analysis contributes to optimizing concrete-embedded 5G antenna sensor designs and establishes a foundational framework for estimating unknown dielectric parameters of cementitious composites.

Teachers' Efforts to Overcome Barriers to Integrated Social Studies Learning at Junior High School

Purpose of the study: The purpose of this research is to find out what obstacles there are in Integrated Social Studies learning and to find out what efforts have been made by teachers to overcome barriers to learning Integrated Social Sciences.&#x0D; Methodology: The methodology used in this research is a qualitative method. The sampling technique used was purposive sampling, taking Integrated Social Sciences teachers and class 8A students at junior high school as data sources. Data was collected through passive observation by researchers and in-depth interviews.&#x0D; Main Findings: Research findings show that Integrated Social Studies learning at junior high school is considered boring by students because of the load of material presented by teachers and the lack of facilities and infrastructure, especially in terms of electronic media.&#x0D; Novelty/Originality of this study: This research contributes to the understanding of the obstacles and efforts made in Integrated Social Sciences learning. The results of this research can be a reference for related parties, such as schools and teachers, to overcome the problems faced in Integrated Social Sciences learning and improve the quality of learning.

A semi-analytical solution for the in-plane stress fields in isotropic convex finite solids with circular holes reinforced with cylindrically orthotropic rings

In this paper a semi-analytical solution for the stress distribution in a finite convex plate with a reinforced hole and subjected to a general loading condition is presented. The method described accounts for the geometrical parameters of the plate, as well as material properties and loading conditions, which can be applied internally to the hole boundary and externally to the outside boundaries of the plate. An extensive validation of the proposed solution is carried out comparing the theoretical predictions with results from various finite element analyses, showing an excellent agreement.