Element Method Analysis Research Articles

Carbon sequestration behavior of magnesium oxychloride cement based on salt lakes magnesium residue and industrial solid waste

With the extensive utilization of lithium-ion battery in the electric vehicle and energy storage field, the consumption of lithium has been sharply increasing. Lithium resource occurrence area were facing increasing environmental pressure, particularly the magnesium residue (MR) produced in the lithium extraction process, and a sustainable exploitation pathway have not been established. In the framework of "net-zero", MRs were onverted to Salt lake magnesium oxide (SL-MgO) which was characterized by various elemental and surface analysis methods. Magnesium oxychloride cement (MOC) was prepared form SL-MgO and two industrial solid wastes [fly ash (FA) and phosphogypsum (PG)], and its carbon sequestration capacity was analyzed and evaluated. If all the MRs produced from the lithium extraction process were used to manufacture MOC materials for CO2 sequestration. When the PG content was 20 %, the CO2 sequestration capacity of the MOC was 0.29 kg/m2, the compressive strength was 85.30 MPa, and the MOC neutralized 220.10 % of the CO2 emissions from the lithium extraction process. In this procedure, evidence was found of the typical metastable carbonate products identifiable. Overall, utilizing MRs and industrial solid waste to manufacture new low-carbon MOCs may become the most direct and effective countermeasures to alleviate environmental pressure in these regions.

A comprehensive finite element framework for modeling of PEX-Al-PEX composite pipes

While PEX-Al-PEX composite pipes are widely used in various applications, suitable tools and models for simulating their performance under different working conditions have not been made available. Therefore, the present study aims to develop a comprehensive finite element model to study the behavior of PEX-AL-PEX pipes at different temperatures and strain-rates. To achieve this, the properties of the pipe layers have been obtained for different temperature and strain-rate values through experimental tests. To assess the accuracy of the developed finite element model, the lateral compression and the split-disc tension tests have been performed under different conditions using both experimental and finite element analysis methods, and their results have been compared. The proposed model can be used to study the behavior of PEX-AL-PEX pipes with different materials and geometries in various conditions and applications, as well as for optimizing the design and manufacturing of these pipes.

Thermal and Luminescent Properties of Multi-Ligand Complexes of Europium(III) with Pyrazine-2-carboxylic Acid

Eu(III) compounds with pyrazine-2-carboxylic acid and nitrogen- and phosphorus-containing neutral ligands were synthesized. Using the methods of chemical elemental and thermal analysis and IR spectroscopy, the composition of the complexes and the method of coordination of carboxylate ions were established. The most thermally stable compounds have been identified. The luminescent characteristics of complex compounds have been studied. It was found that the maximum luminescence intensity is characteristic of europium(III) pyrazinate with triphenylphosphine oxide. The morphological structure and dispersion of the complexes were determined.

Adding More Shape to Nanoscale Reference Materials─LiYF4:Yb,Tm Bipyramids as Standards for Sizing Methods and Particle Number Concentration.

The increasing industrial use of nanomaterials calls for the reliable characterization of their physicochemical key properties like size, size distribution, shape, and surface chemistry, and test and reference materials (RMs) with sizes and shapes, closely matching real-world nonspheric nano-objects. An efficient strategy to minimize efforts in producing nanoscale RMs (nanoRMs) for establishing, validating, and standardizing methods for characterizing nanomaterials are multimethod nanoRMs. Ideal candidates are lanthanide-based, multicolor luminescent, and chemically inert nanoparticles (NPs) like upconversion nanoparticles (UCNPs), which can be prepared in different sizes, shapes, and chemical composition with various surface coatings. This makes UCNPs interesting candidates as standards not only for sizing methods, but also for element-analytical methods like laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS), quantitative bioimaging methods like X-ray fluorescence computed tomography (XFCT), and luminescence methods and correlative measurements. Here, we explore the potential of two monodisperse LiYF4:Yb,Tm bipyramids with peak-to-peak distances of (43 ± 2) nm and (29 ± 2) nm as size standards for small-angle X-ray scattering (SAXS) and tools for establishing and validating the sophisticated simulations required for the analysis of SAXS data derived from dispersions of nonspheric nano-objects. These SAXS studies are supplemented by two-dimensional (2D)-transmission electron microscopy measurements of the UCNP bipyramids. Additionally, the particle number concentration of cyclohexane dispersions of these UCNP bipyramids is determined by absolute SAXS measurements, complemented by gravimetry, thermogravimetric analysis (TGA), and inductively coupled plasma optical emission spectrometry (ICP-OES). This approach enables traceable particle number concentration measurements of ligand-capped nonspheric particles with unknown chemical composition.

Research on Damage Detection of Dual-Rotor Synchronous Excitation Mine Screen Beams Based on Strain Mode Difference Vibration Mode Analysis

The frame beam structure of the mine screen, subjected to various excitations, is a critical component of mining machinery. Its stress is intricate, the operational environment is severe, and damage can lead to catastrophic failures resulting in machinery destruction and fatalities. Based on the characterization of the vibration response of mine screen frame beams with varying degrees of damage at the same location and with the same degree of damage but at different locations, this paper develops a method of strain modal difference vibration pattern analysis and damage feature extraction for the detection of structural damage in beams. This method is based on the sensitivity of the sudden change in vibration strain modal difference to small deformations. This method solves the problem of using the conventional structural finite element analysis or experimental modal analysis methods to obtain the displacement mode, intrinsic frequency, and other characteristics, which make it difficult to effectively identify the actual engineering, with the damage conditions of the damage state and damage location of the mine screen frame beam problems. The feasibility and validity of the engineering application of the concept are demonstrated through instances.

Research on the design and thermal performance of vacuum insulation panel composite insulation materials

This study introduces a novel design methodology for composite insulation material aimed at reducing the operational energy consumption of buildings. Vacuum Insulation Panels (VIPs) are recognized for their excellent insulating properties due to their vacuum-sealed nature that minimizes thermal transmittance. However, VIPs are susceptible to damage from temperature stress and abrasion, which can compromise vacuum integrity and degrade performance over time. To mitigate this, a protective layer of rock wool board is adhered to the exterior of the VIP to create a composite insulation material. The thermal conductivity characteristics of the composite insulation materials are experimentally measured and then corroborated with simulations using ANSYS software to affirm the precision of finite element analysis methods. A composite Insulation wall model is constructed using ANSYS to analyze the impact of varying the thickness of the composite insulation materials and the pressure within the VIP on thermal performance. The findings demonstrate that the thermal transmittance coefficient of the composite insulated wall diminishes with increased insulation material thickness and rises with increased pressure within the VIP. Additionally, rock wool boards significantly enhance the durability of the composite insulation material.

Numerical and analytical study on the punching shear capacity prediction for eccentrically loaded flat slabs with openings

The punching shear behavior of interior flat slab was examined in this study in the absence of shear reinforcement using numerical and analytical techniques. The effect of sensitive parameters was investigated and their influence was examined and reported including the opening existence and location, loading eccentricity, and slab height. The effect of the reinforcement ratio is neglected in most of the literature models and code provisions with the influence of loading eccentricity being addressed inappropriately. Therefore, this study adopted the nonlinear finite element analysis (NLFEA) method for the numerical part where the flat slab punching shear behavior was studied in detail. Results were compared in their behavior at both cracking and ultimate stages, absorbed energy, elastic and plastic stiffnesses, and general trend lines were provided. The effect of the reinforcement ratio was assessed indirectly with slabs of similar reinforcement area and different slab effective depths (65, 95, 125, and 155) mm where a 25 mm concrete cover was used. In addition, the NLFEA punching shear capacity results were compared with three international codes (American Concrete Institute (ACI318-119), EuroCode (EC2), and Model Code (MC2010)) to highlight their potential predictability and weakness points. It was found that the MC2010 has the most conservative prediction, followed by the EC2 and the ACI318-19 predictions. Therefore, two modification parameters were proposed for the ACI318-19 punching shear capacity calculation with R2 value of 0.98. The modified version of the ACI318-19 was validated using experimental data from the literature proving a high prediction capability.

UV ozone‐modified Fe3O4‐PDMS film for solvent‐driven soft actuators with controlled and multi‐stable deformations

AbstractIn recent years, solvent‐driven actuators have been capable of controlling deformations in response to external stimuli. However, a magnetic polydimethylsiloxane (PDMS) composite film with magnetic properties is traditionally developed using the micro‐electro‐mechanical system process. Although it has general actuation deformation, the composite film suffers from the problems of actuation and control. Here, this is done by co‐mixing PDMS and ferrosoferric oxide (Fe3O4) then waiting for curing and then undergoing ultraviolet‐ozone (UVO) surface treatment. By adjusting the time and orientation of the UVO treatment, a series of solvent‐driven actuators with multiform steady‐state structures (e.g., mono/bistable helix) is proposed. In addition, the deformation of the composite film under different geometrical parameters and surface constraints was visually predicted by incorporating finite element analysis methods. In addition, the controlled deformations of the composite film (such as box‐like, folded, and so on) are carried out by self‐morphing design. Finally, four bionic applications are also proposed to demonstrate the practical use of soft actuators based on Fe3O4‐PDMS films in bionic robots. This work provides new strategies for designing and fabricating programmable and controllable soft actuators and lays the foundation for a wide range of smart material applications.

Novel Poly(N‐(1‐cyclohexylethyl)Acrylamide‐co‐Styrene‐co‐Ethyleneglycol Dimethacrylate) Synthesis for Efficient Methylene Blue Adsorption from Aqueous Solutions Synthesis

AbstractSynthesis and evaluation of a new polymeric adsorbent for adsorbing methylene blue (MB) from these economical aqueous solutions were investigated. In the first step of the study, N‐(1‐cyclohexylethyl)acrylamide (CEA) monomer was synthesized using S‐(+)‐1‐cyclohexylethylamine and acryloyl and the obtained CEA was analyzed by FTIR, 1H‐NMR, and 13C‐NMR. Then, a poly(CEA‐co‐Styrene‐co‐EGDMA) copolymer was obtained by cross‐linking CEA monomer, ethylene glycol dimethacrylate (EGDMA) and styrene monomers by subsequent radical polymerization episodes. FTIR, solid‐NMR, and elemental analysis methods were used for the characterization of this copolymer. In the last step of the study, the obtained poly(CEA‐co‐Styrene‐co‐EGDMA) copolymer was used as an adsorbent to adsorb MB from aqueous solutions. In the study, various factors such as adsorption properties, adsorbent dose, contact time, initial concentration, and solution pH were investigated. In the study, the most suitable adsorbent dose was determined as 0.1 g, initial solution concentration as 500 mg/L, contact time as 70 min, and pH as 7. Adsorption capacity was determined as 256.4 mg/g at 25 °C. As a result of the analysis of kinetic data, it was found that the model with the highest regression coefficient and the best fit with the experimental data was the pseudo‐second‐order kinetic model.

Numerical and experimental analysis of Al/GFRP joint for optimization of adhesive bonding strength using response surface method by considering surface patterning of the joints

Nowadays, adhesive bonding of metals and composites is widely used in the aerospace, automotive and military industries. In the present research, the finite element analysis (FEA) and response surface method (RSM) are used to optimize adhesive bonding strength between aluminum (Al) and glass fiber reinforced polymer (GFRP). For this purpose, the influence of the parameters of joint type, groove shape, groove number, and groove angle was investigated on the bonding strength. The joint type includes Al/Al, Al/GFRP and GFRP/GFRP, the groove shape includes V-shape, square and concave, the groove number includes 1, 3 and 5 grooves, and the groove angle includes 0, 45 and 90º. In order to model the crack growth in the simulation of adhesive bonding, the cohesive zone model was applied. Finally, the optimal sample is fabricated to examine its strength in temperature-humidity environmental conditions. The results of simulation and optimization indicated that the bonding strength improved in Al/Al mode with one square groove at 0° groove angle. The stress-strain diagram obtained from the simulation and optimization results was in good agreement with the sample made under optimal conditions. Moreover, the tensile strength of the optimal sample at temperature-humidity conditions was higher than the tensile force of the sample without groove.

Finite element analysis method for the sliding cable analysis: The sliding variable method

A sliding cable structure is typically characterized by uncertainty of sliding and complexity of friction at the cable-strut joints, which makes accurate and efficient analysis difficult. In this study, we have proposed the sliding variable method, to simulate the cable sliding process considering friction equivalently and analyze the internal force and deformation response at the equilibrium state quickly and accurately. The sliding variable method takes the sliding vector of the cable at cable-strut joints as the basic variable, extracts the slippage stiffness matrix and establishes the cable force balance equation to solve the sliding vector, and simulates the change of cable original length and cable force by applying equivalent temperature load. In this paper, first, the basic principles and calculation procedures of the sliding variable method without considering friction, are discussed in detail to simulate frictionless slip of continuous cable, using with roller-type cable-stayed joints. as an example. On this basis, a calculation model incorporating the effects of friction is analyzed, a method to judge the sliding situation and balance relation of cable-forces is revealed, and the calculation principle and steps of the method are further deduced. Meanwhile, choosing a multi-joint cable–pulleys model as an example, the accuracy and rationality of the sliding variable method with and without considering friction are verified respectively. This method requires a conventional finite element calculation and second calculation alternately. Finally, to improve the practicability and computational efficiency of the sliding variable method, a macro document was compiled using the secondary development function of ANSYS parametric programming language (APDL) according to the basic framework of the sliding variable method. The frictional sliding behaviors in two typical engineering cases, a cable girder and a prestressed fish-belly girder on a foundation pit, are analyzed by using the compiled macro document in finite element program. The results show that the compiled macro document can be both accurate and efficient in calculating and analyzing cable sliding problems and can be easily popularized and applied in engineering practices.

Slope stability analysis of unsaturated colluvial slopes based on case studies of rainfall-induced landslides

Landslides in colluvial soils under rainfall have been identified as a significant problem due to their loose, heterogeneous nature and low shear strength. Evaluation of the stability of colluvial slopes under rainfall conditions is challenging. This study investigated two landslide failure case studies of colluvial soils to understand the failure patterns using finite element (FE) and limit equilibrium (LE) slope stability analysis methods under unsaturated conditions. Transient seepage conditions due to rainfall infiltration and failure were analysed using hydromechanical models. Here, a FE fully coupled hydromechanical model and a sequential coupling of a FE hydrological and LE mechanical model were used to evaluate the failure of variably saturated slopes. Results from the case studies revealed that the failure occurred due to the rise in the groundwater table in both cases. It was evident that there can be significant disparities in the pore water pressure profiles with the fully coupled and sequentially coupled analysis. The dynamic capability of the two models can also affect the interplay between the hydrological and mechanical aspects. When the thickness of the colluvium layer is large, the failure could potentially occur as a deep-seated failure along the boundary of overburden and the bedrock surface due to the large driving force. However, when the thickness is small, failure can occur along the colluvium-weathered rock surface. The outcomes from the study will contribute to mitigate the uncertainty of failure prediction of landslides in colluvial soils.

Improving flexural performance of repaired C/C composites through Ti addition: Mechanism analysis

Ti-doped Ni-based solder was used as the repair agent to recover the flexural performance of the damaged carbon/carbon (C/C) composites. The effects of the contents of Ti on the microstructure, chemical compositions, and flexural strength were investigated. The thermal stress distribution and repair mechanism was studied by finite element analysis methods. The addition of an appropriate amount of Ti enhanced the wetting performance of the repair agent on the surface of C/C composites. Besides, the TiC hard particles formed at the interface provided strengthen effect, and form a gradient structure of coefficient of thermal expansion (CTE), thereby enhancing the interface bonding ability and improving the flexural performance of the repaired C/C composites. The flexural strength was the highest with a recovery rate of 92.6 % when the content of Ti was 5 wt%. This work provides a strategy for the engineering application and improving the damage repair of C/C composites.

A Flexible Asymmetric Supercapacitor with High-Performance and Long-Lifetime: Fabrication of Nanoworm-Like-Structured Electrodes Based on Polypyrrole-Thiosemicarbazone Complex.

A thiosemicarbazone-based iron(III) complex is prepared and used in the preparation of a supercapacitor electrode material. This electrode is produced by a solvothermal reaction of polypyrrole and the complex on carbon felt. The characterization of the complex and material is carried out using UV-vis, elemental analysis, FT-IR, XRD, BET, and TGA methods, and the surface morphology is examined using SEM technique. Because the interaction of electrode and electrolyte is of great importance in energy storage systems, as the surface area and pore volume increase, electrode ions at the electrode/electrolyte interface leak to the inner surfaces and interact with the larger surface area, which increases the charge storage performance. The electrode material, nano-worm structure, reached the highest specific capacitance value of 764.6 F g-1 at 5 mV s-1. Compared to the capacitance value of polypyrrole in its pure form, it is observed to exhibit an 187.2% increase. The highest specific capacitance value of the asymmetric supercapacitor (ASC) formed with a graphite electrode is 318.1 F g-1 at the current density of 1 Ag-1. Moreover, ASC reached a wide working potential of 1.8 V in an aqueous electrolyte and exhibited ultra-long cycle life (112%), maintaining its stability after 10000 cycles.

Effects of pyrolysis temperatures on the structural properties of straw biochar and its adsorption of tris-(1-chloro-2-propyl) phosphate

To investigate the effect of pyrolysis temperature on the adsorption behavior of the emerging organic pollutant tris-(1-chloro-2-propyl) phosphate (TCIPP) on biochar, corn stover was used as raw materials to prepare biochars at different pyrolysis temperatures (250, 350, 500, 700 °C) through limited oxygen carbonization. Elemental analysis, Boehm titration, FTIR, XPS, and other analytical methods were used to reveal the effect of pyrolysis temperature on the physicochemical properties of biochar and its mechanism of TCIPP adsorption. The results showed that the pyrolysis temperature had a significant impact on the physicochemical properties of biochar. As the pyrolysis temperature increases, the specific surface area of biochar rises from 3.083 m2/g to 435.573 m2/g, the pH value increases from 6.60 to 10.66, the mass percentage of C increases from 63.10 to 80.58%, and the mass percentage of O decreases from 26.42 to 9.20%. Additionally, the hydrophobicity and aromaticity of biochar also increase with rising pyrolysis temperature, while its polarity decreases. Boehm titration, FTIR, and XPS analysis showed that the total amount of functional groups on the surface of biochar decreased relatively with increasing temperature. Functional groups such as -OH, C = C/C = O, and C-O-C participated in the adsorption of TCIPP on biochar, and ester groups were produced after adsorption. The adsorption process of TCIPP on biochar fits best with the pseudo-second-order equation, indicating that the adsorption process is mainly chemical adsorption, and the main rate-controlling stage is intraparticle diffusion. The isothermal adsorption results were more in line with the Temkin model, indicating that the adsorption process of TCIPP on biochar was mainly surface adsorption. As the pyrolysis temperature increases, the maximum adsorption capacity of biochar increases from 0.8837 mg/g to 2.2574 mg/g. The adsorption process of TCIPP on biochar mainly included pore filling, hydrogen bonding, P-π interaction, hydrophobic interaction, and electrostatic attraction. Among them, pore filling, P-π interaction, and hydrophobic interaction were significantly enhanced with increasing temperature, while hydrogen bonding was relatively weakened. This study will provide a theoretical basis and technical support for the removal of TCIPP from water using biochar adsorption.

Applicability evaluation technology for steel small diameter pipes containing external surface corrosion defects

With the continuous operation of oil and gas stations and petrochemical equipment, it has been found that steel small bore pipelines have different degrees of corrosion defects, which have led to pipeline cracking and medium leakage, and have increasingly attracted great attention of their oil and gas and chemical enterprises. In order to ensure the safe operation of the small diameter pipes with external surface corrosion defects, the influence law of the size of corrosion defects on the bearing capacity of the small diameter pipes were studied by finite element analysis and test simulation method, and the damage mechanism and failure form were analyzed, and the failure pressure prediction formula of the small diameter pipes with defects was fitted. It provides technical guidance for the applicability evaluation of corrosion-containing steel small diameter pipes in oil and gas chemical stations or installations.

Energy Dispersive X-Ray Fluorescence Spectrometry Using a Matrix Corrected Fundamental Parameters Algorithm vs. Acid Digestion with ICP-AES: A Comparison of Two Methods for Soil Elemental Analysis

ABSTRACT Energy dispersive X-ray fluorescence spectrometry (ED-XRF) is evaluated as an alternative to conventional acid-mediated soil digestion methods for analysis of aluminum (Al), calcium (Ca), iron (Fe), potassium (K), magnesium (Mg), manganese (Mn), sodium (Na), phosphorus (P), silicon (Si), strontium (Sr), titanium (Ti), and zirconium (Zr). The Kellogg Soil Survey Laboratory (KSSL) currently uses microwave-assisted digestion with inductively coupled plasma – atomic emission spectrometry (ICP-AES) to measure the 12 elements (Al, Ca, Fe, K, Mg, Mn, Na, P, Si, Sr, Ti, Zr). The equipment needed to conduct the digestion method is expensive, the materials are hazardous, and the method is laborious. The Kellogg Soil Survey Laboratory (KSSL) has observed variable elemental recoveries for certain elements. The objective of the study was to evaluate an ED-XRF method as an alternative to the KSSL digestion method. The literature offers few examples of X-ray fluorescence (XRF) method development and validation. The candidate ED-XRF method offered a more efficient, less expensive, and less hazardous approach for measuring the 12 elements. Relative to the digestion method, the candidate ED-XRF method showed improved precision and accuracy for specific elements.

An improved approach to compensating for cure‐induced deformation to manufacture composite aircraft skin accurately

AbstractThe purpose of this paper is to compensate for the cure‐induced deformation to manufacture composite aircraft skin with variable curvature accurately. Firstly, a finite element analysis (FEA) method appropriate for curing simulation was described. Then, the discrete curvature‐based displacement adjustment (DC‐DA) method for mold surface compensation was proposed. The DC‐DA method utilizes the discrete curvature of the section points to obtain a smooth compensated curve. Finally, a skin part was selected to prove its effectiveness. The experimental results showed that after the mold's surface was modified by the DC‐DA method with the FEA‐predicting deformation as input, the forming shape could meet the requirement of the part accuracy in one cycle. The DC‐DA method was also compared with the displacement adjustment (DA) method and proved to be more efficient for the compensation of composite skin with variable curvature.Highlights The FEA is appropriate for the calculation of the skin's curing deformation. The DC‐DA method is efficient for compensating for the skin's deformation. The shape of the case part could meet the requirement of accuracy in one cycle.

Fatigue Analysis on a Newly Designed Hip Implant with Finite Element Method

This study used Finite Element Analysis (FEA) and Reverse Engineering (RE) methods to assess the fatigue performance of an originally designed cementless hip implant. The implant prototype was initially scanned using 3D scanning technology, and a finite element model was created. The implant was analyzed under dynamic loads for six different biomaterials commonly used, namely Ti-6Al-4V (Grade5), ASTM F3046 (Ti-3Al-2.5V), ASTM F75 (CoCr), ASTM F562(MP35N), ASTM F136(Ti6Al4V ELI), ASTM F67 (Ti Grade 4), and the fatigue life was evaluated. The results showed that the ASTM F75 (CoCr) implant had the highest stress and the ASTM F67 (Ti Grade 4) implant had the lowest stress. Also, Ti6Al4V (Grade 5) implant is more resistant to fatigue than their counterparts made from ASTM F75 (CoCr), ASTM F136 (Ti6Al4V ELI) and ASTM 3046 (Ti-3Al-2.5V).

The Impact of Stress Distribution on The Electrical Performance of Different Silver Stretchable Conductive Ink Pattern Using FEA Simulation

Stretchable conductive ink has been widely investigated to be used in the fabrication of stretchable electrical devices. Experimentation methods to test the mechanical and electrical behaviours of the stretchable conductive ink composite are commonly applied; however, not much of the computational approach has been scrutinized to validate the results further. This paper employs the finite element analysis method to investigate the relationship between the stress and strain distribution of the stretchable conductive ink with the highest strain obtained. This research validates the past experimentation works of different patterns of stretchable conductive ink for its stretchability and electrical performance. The maximum Von Mises stress (VMS) and maximum principal strain of the stretchable conductive ink played a significant role in determining its electrical performance, rather than the localisation of high stress and strain at specific locations within the stretchable conductive ink pattern. Zigzag pattern exhibited the lowest maximum stress and strain concentration at 57.826 MPa and 4.05% while straight pattern suffered the highest respective values at 118.143 MPa and 10.39%. The lower maximum Von-Mises stress and principal strain contributed to a better stretchability which is indicated by a higher strain rate prior to electrical conductivity.