Industrial applications of calcium carbonate (CaCO3), an extensively used inorganic powder, are restricted by its hydrophilicity and lack of affinity for oils. The potential value of calcium carbonate is magnified by surface modification strategies, which lead to better dispersion and stability in organic substrates. In this research, ultrasonication assisted the modification of CaCO3 particles with a synergistic combination of silane coupling agent (KH550) and titanate coupling agent (HY311). The modification's efficacy was gauged using the oil absorption value (OAV), the activation degree (AG), and the sedimentation volume (SV). Compared to KH550, HY311 exhibited a more pronounced effect on the modification of CaCO3, with ultrasonic treatment acting as an ancillary process. Through response surface analysis, the most favorable modification parameters were pinpointed: HY311 at 0.7%, KH550 at 0.7%, and an ultrasonic time of 10 minutes. Modified CaCO3's OAV, AG, and SV, under the given conditions, were determined to be 1665 grams of DOP per 100 grams, 9927 percent, and 065 milliliters per gram, respectively. SEM, FTIR, XRD, and thermal gravimetric analyses provided conclusive evidence of a successful coating of HY311 and KH550 coupling agents on the CaCO3 surface. The modification performance was substantially improved through the optimized dosages of two coupling agents and the duration of ultrasonic treatment.
Multiferroic ceramic composites, a result of combining magnetic and ferroelectric materials, exhibit the electrophysical properties detailed in this work. The composite's ferroelectric components are represented by the chemical formulas PbFe05Nb05O3 (PFN), Pb(Fe0495Nb0495Mn001)O3 (PFNM1), and Pb(Fe049Nb049Mn002)O3 (PFNM2), while the nickel-zinc ferrite (Ni064Zn036Fe2O4, designated as F) constitutes the magnetic component. Measurements of the crystal structure, microstructure, DC electric conductivity, and ferroelectric, dielectric, magnetic, and piezoelectric properties were undertaken on the multiferroic composites. The trials definitively demonstrate the composite specimens' superior dielectric and magnetic qualities at room temperature. The crystal structure of multiferroic ceramic composites is biphasic, consisting of a ferroelectric phase (tetragonal system) and a magnetic phase (spinel structure). No foreign phase is present. Improved functional parameters are observed in composites with manganese admixtures. The addition of manganese to the composite sample leads to a more uniform microstructure, enhanced magnetic characteristics, and a decrease in electrical conductivity. Alternatively, the maximum values of m associated with electric permittivity diminish in tandem with an augmentation of manganese in the ferroelectric component of the composite. Nonetheless, the dielectric dispersion, observed at elevated temperatures (correlated with heightened conductivity), vanishes.
The fabrication of dense SiC-based composite ceramics was achieved using solid-state spark plasma sintering (SPS) and the ex situ addition of TaC. As raw materials, commercially available silicon carbide (SiC) and tantalum carbide (TaC) powders were chosen. The technique of electron backscattered diffraction (EBSD) analysis was used to examine the grain boundary distribution within SiC-TaC composite ceramics. A rise in TaC correlated with a significant reduction in the range of misorientation angles for the -SiC phase. The findings indicated that the external pinning stress from TaC significantly impeded the augmentation of -SiC grain size. Specimen transformability was significantly hampered by the inclusion of 20 volume percent SiC in its composition. TaC (ST-4) implied that newly nucleated -SiC particles embedded in the framework of metastable -SiC grains might have resulted in the increased strength and fracture toughness. Examining the as-sintered silicon carbide material, which includes 20% by volume of SiC. The TaC (ST-4) composite ceramic's properties included a relative density of 980%, a bending strength of 7088.287 MPa, a fracture toughness of 83.08 MPa√m, an elastic modulus of 3849.283 GPa, and a Vickers hardness of 175.04 GPa.
Manufacturing imperfections, such as fiber waviness and voids, are frequently observed in thick composite materials, and can jeopardize structural soundness. A novel approach for imaging fiber waviness in substantial porous composites was devised based on a combination of numerical and experimental methods. The approach hinges on measuring the non-reciprocity of ultrasound propagation along varied wave paths inside a sensing network constructed using two phased array probes. To understand the reason behind ultrasound non-reciprocity in wavy composites, the research team implemented time-frequency analytical procedures. medical worker Employing ultrasound non-reciprocity and a probability-based diagnostic algorithm, the number of elements in the probes and corresponding excitation voltages were subsequently determined for fiber waviness imaging. In thick, corrugated composites, fiber angle variations led to ultrasound non-reciprocity and fiber waviness, yet imaging was achieved with successful visualization regardless of voids. In this study, a new method for ultrasonic imaging of fiber waviness is presented, which is projected to lead to improvements in the processing of thick composite materials, eliminating the prerequisite for prior material anisotropy information.
The study explored the resilience of highway bridge piers reinforced with carbon-fiber-reinforced polymer (CFRP) and polyurea coatings against combined collision-blast loads, evaluating their practicality. LS-DYNA software facilitated the creation of detailed finite element models of CFRP- and polyurea-retrofitted dual-column piers. These models accounted for blast-wave-structure interaction and soil-pile dynamics, and were used to simulate the combined impact of a medium-size truck collision and a close-range blast. Dynamic responses of bare and retrofitted piers under varying demand levels were investigated through numerical simulations. The computational analysis of the numerical data confirmed that the use of CFRP wrapping or polyurea coatings effectively mitigated the combined collision and blast impacts, thereby improving the pier's structural response. To identify the best in-situ retrofit solutions for controlling parameters and designing optimal configurations, parametric analyses were carried out on dual-column piers. AK 7 datasheet The results from the parameters that were tested showed that the retrofitting method implemented at the middle height of both columns' base was identified as the optimal design to improve the bridge's multi-hazard resistance for the pier.
Cement-based materials, capable of modification, have seen graphene's exceptional properties and unique structure extensively investigated. Although this is true, a complete and organized record of the status of numerous experimental findings and related applications is needed. Accordingly, this document analyzes graphene materials that boost the functionalities of cement-based products, considering aspects such as workability, mechanical robustness, and longevity. Concrete's mechanical performance and durability are analyzed in relation to the influence of graphene material properties, mass ratios, and curing times. Graphene is shown to be useful in improving interfacial adhesion, enhancing electrical and thermal conductivity in concrete, absorbing heavy metal ions, and gathering building energy. Concluding the current study, its inherent issues are evaluated, and potential future developments are anticipated.
In the realm of high-quality steel manufacturing, ladle metallurgy stands out as a critical steelmaking technology. In ladle metallurgy, the technique of blowing argon at the bottom of the ladle has been used for a considerable number of decades. Up to this point, the problem of bubble breakage and coalescence has remained largely unsolved. To gain profound understanding of the intricate fluid dynamics in a gas-stirred ladle, the Euler-Euler model and population balance model (PBM) are coupled to analyze the complex flow patterns within the ladle. Utilizing the Euler-Euler model to anticipate two-phase flow, coupled with the PBM method to determine bubble sizes and distributions. The coalescence model, incorporating the effects of turbulent eddy and bubble wake entrainment, determines the evolution path of the bubble size. Calculations reveal that omitting the effect of bubble breakage in the mathematical model results in an incorrect prediction of bubble distribution patterns. Labio y paladar hendido Regarding bubble coalescence in the ladle, turbulent eddy coalescence is the primary process, and wake entrainment coalescence occurs to a lesser extent. Subsequently, the enumeration of the bubble-size category plays a vital role in describing the conduct of bubbles. The size group, number 10, is recommended for accurately predicting the spread of bubble sizes.
The widespread adoption of bolted spherical joints in modern spatial structures is a testament to their installation advantages. Despite the investment in research, the mechanisms behind their flexural fracture behavior remain poorly understood, hindering efforts to prevent catastrophe for the entire structure. This paper's objective is to experimentally investigate the bending resistance of the fractured section, marked by a raised neutral axis and fracture characteristics influenced by differing crack depths in screw threads, given the recent strides in closing the knowledge gap. In a three-point bending framework, two complete bolted spherical joints, each utilizing a different bolt gauge, were investigated. Typical stress fields and resulting fracture modes are initially used to reveal the fracture characteristics of bolted spherical joints. A new and validated theoretical model is presented for calculating the flexural bending capacity of fractured sections having a raised neutral axis. For the estimation of stress amplification and stress intensity factors regarding the crack opening (mode-I) fracture within the screw threads of these joints, a numerical model is developed.