Influence Of Material Composition Research Articles

Effect of four-component binder on characteristics of self-compacting and fibre-reinforced self-compacting mortars

AbstractThe hydration heat of a four-component binder consisting of Portland cement (CEM I 42.5 R), blast-furnace slag (BFS), metakaolin (MK), and silica fume (SF) was investigated using a conduction calorimeter and thermal analytical method to optimize the material composition of self-compacting mortar (SCM). Then, the influence of material composition with different substitution levels (0, 25, 30, and 35% labelled as SCM100, SCM75, SCM70, and SCM65) on physical and mechanical properties of the mortars with two volumetric binder sand ratios of 1:1 and 1:2 (cement: sand) was evaluated. Furthermore, two mortar compositions comprising SCM75 and sand at 1:1 and 1:2 ratios were used to prepare fibre-reinforced self-compacting mortars in five combinations (0, 0.25, 0.5, 0.75, and 1%) of two fibres (polypropylene-PPF and basalt-BF) at a constant content of 1.00 vol%. The properties of the prepared samples were investigated with respect to the characteristics of self-compactibility and mechanical properties of fresh and hardened states, respectively. The rheology characteristics expressed by slump flow, V-funnel, and T20 were found following the EFNARC guidance. The partial replacement of cement by supplementary cementitious materials has enhanced the performances (compressive and flexural strengths, dynamic modulus of elasticity) of self-compacting mortars from the 7th day through pozzolanic activity. Furthermore, adding fibres has enhanced the DME and microstructure of the self-compacting mortars.

Free vibration characteristics of elastic foundation-supported porous functionally graded nanoplates using Rayleigh-Ritz approach

PurposeThe purpose is to explore the free vibration behaviour of elastic foundation-supported porous functionally graded nanoplates using the Rayleigh-Ritz approach. The goal of this study is to gain a better knowledge of the dynamic response of nanoscale structures made of functionally graded materials and porous features. The Rayleigh-Ritz approach is used in this study to generate realistic mathematical models that take elastic foundation support into account. This research can contribute to the design and optimization of advanced nanomaterials with potential applications in engineering and technology by providing insights into the influence of material composition, porosity and foundation support on the vibrational properties of nanoplates.Design/methodology/approachA systematic methodology is proposed to evaluate the free vibration characteristics of elastic foundation-supported porous functionally graded nanoplates using the Rayleigh-Ritz approach. The study began by developing the mathematical model, adding material properties and establishing governing equations using the Rayleigh-Ritz approach. Numerical approaches to solve the problem are used, using finite element methods. The results are compared to current solutions or experimental data to validate the process. The results are also analysed, keeping the influence of factors on vibration characteristics in mind. The findings are summarized and avenues for future research are suggested, ensuring a robust investigation within the constraints.FindingsThe Rayleigh-Ritz technique is used to investigate the free vibration properties of elastic foundation-supported porous functionally graded nanoplates. The findings show that differences in material composition, porosity and foundation support have a significant impact on the vibrational behaviour of nanoplates. The Rayleigh-Ritz approach is good at modelling and predicting these properties. Furthermore, the study emphasizes the possibility of customizing nanoplate qualities to optimize certain vibrational responses, providing useful insights for engineering applications. These findings expand understanding of dynamic behaviours in nanoscale structures, making it easier to build innovative materials with specific features for a wide range of industrial applications.Originality/valueThe novel aspect of this research is the incorporation of elastic foundation support, porous structures and functionally graded materials into the setting of nanoplate free vibrations, utilizing the Rayleigh-Ritz technique. Few research have looked into this complex combo. By tackling complicated interactions, the research pushes boundaries, providing a unique insight into the dynamic behaviour of nanoscale objects. This novel approach allows for a better understanding of the interconnected effects of material composition, porosity and foundation support on free vibrations, paving the way for the development of tailored nanomaterials with specific vibrational properties for advanced engineering and technology applications.

Linking the Intrinsic Electrical Response of Ferroelectric Devices to Material Properties by Means of Impedance Spectroscopy

Ferroelectric devices have gained attention in recent years as a potential solution for ultra-low power computing due to their ability to act as memory units and synaptic weights in brain-inspired architectures. One way to study the behavior of these devices under different conditions, particularly the influence of material composition and charge trapping on ferroelectric switching, is through impedance spectroscopy. However, the parasitic impedance of the metal lines that contact the electrodes of the device can affect the measured response and interpretation of the results. In this study, we examined the frequency response of ferroelectric tunnel junctions (FTJs) with a metal-dielectric-ferroelectric-metal (MDFM) stack at various voltages, starting from the analysis of single layer capacitors (MFM and MDM) to better interpret FTJs results. To accurately assess the intrinsic response of the device, we developed a method that estimates and removes the parasitic access impedance contribution, which was validated by means of physics-based simulations. This method allows quantifying the intrinsic device-level variability of FTJs and, for the first time, to investigate the relation between the thickness of the dielectric layer, the equivalent phase composition of the ferroelectric material, and the magnitude of the peak in the frequency response, often assumed to be related to charge trapping only.

Influence of material composition on post-failure behavior of overburden dumps in opencast coal mines

Influence of material composition on post-failure behavior of overburden dumps in opencast coal mines

Electric Field‐Driven Dielectrophoretic Elastomer Actuators

AbstractDielectrophoresis is the electro‐mechanical phenomenon where a force is generated on a dielectric material when exposed to a non‐uniform electric field. It has potential to be exploited in smart materials for robotic manipulation and locomotion, but to date it has been sparsely studied in this area. Herein, a new type of dielectrophoretic actuator exploiting a novel electroactive polymer is described, termed as dielectrophoretic elastomer (DPE), which undergoes electric field‐driven actuation through dielectrophoresis. Unique deflection and morphing behavior of the elastomer induced by controlling the dielectrophoretic phenomenon, such as out‐of‐plane deformation and independence of electric field polarity, are illustrated. The dielectric and mechanical properties of the DPE are studied to gain insight into the influence of materials composition on deformation. Actuation performance using different electrode parameters is experimentally investigated with supplementary analysis through finite element simulation, revealing the relationship between electric field inhomogeneity and deflection. The applications of DPE actuators in a range of robotic devices is demonstrated, including a pump, an adjustable optical lens, and a walking robot. This diverse range of applications illustrates the wide potential of these new soft‐and‐smart electric field‐driven materials for use in soft robotics and soft compliant devices.

An integrated microscopical study of surface properties and surface effects in superprotonic (K1-x(NH4)x)3H(SO4)2 crystals

Surface properties of superprotonic (K1-х(NH4)x)3H(SO4)2 (x ≥ 0.57) single crystals and their evolution under humidity were studied by optical polarization microscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDXS). Traditional method of atomic force microscopy (AFM) and sophisticated methods such as Kelvin probe force microscopy (KPFM) and scanning capacitance force microscopy (SCFM) were also used. Fresh and aged cleavage surfaces perpendicular and parallel to the c axis of the trigonal superprotonic phase were examined. The effect of air humidity on the surface morphology, surface conductivity, surface potential and surface capacitance was studied. The influence of material composition and surface orientation was considered. During ageing for 430 h, the (001) sample surfaces, initially stepped, were smoothened, surface electric potential changed from negative greater than a hundred of millivolts in absolute value to positive of about 80 mV, and a modified layer containing new crystal phases was formed.

Mathematical Approach for Mechanical Behaviour Analysis of FGM Plates on Elastic Foundation

This paper presents the flexural analysis of functionally graded plates resting on elastic foundations using new two-dimensional (2D) and quasi-three-dimensional (quasi-3D) higher order shear deformation theories. The main interesting feature of this theory is that it proposes a new displacement field with undetermined integral variables which involves only five unknown functions, unlike other shear and normal deformation theories, hence making it easier to use. A parabolic transverse shear deformation shape function satisfying the zero shear stress conditions on the plate outer surfaces is considered. The elastic foundation follows the Pasternak mathematical model. The material properties change continuously across the thickness of the FG plate using different distributions: power law, exponential, and Mori–Tanaka models. The governing equations of FG plates subjected to sinusoidal and uniformly distributed loads are established through the principle of virtual works and then solved via Navier’s procedure. In this work, a detailed discussion on the influence of material composition, geometric parameters, stretching effect, and foundation parameters on the deflection, axial displacements, and stresses is given, and the obtained results are compared with those published in previous works to demonstrate the accuracy and the simplicity of the present formulations. The different obtained results were found to be in good agreement with the available solutions of other higher-order theories. The proposed model is able to represent the cross section warping in the deformed shape and to demonstrate the validity and efficiency of the approach, the findings reported herein prove that this theory is capable of predicting displacements and stresses more accurately than other theories, as its results are closer when compared to numerical methods reported in other literatures.

Influence of material composition on the morphology and engineering properties of waste plastic binder composite for construction purposes

Ways of mitigating the menace caused by the abundance of waste plastic generated have been a global concern. Efforts are geared towards intensification of the recycling culture for circular economy. Recent studies combined waste plastic and sand to make Waste Plastic Binder (WPB) composite materials. However, sand mining operation has been associated with environmental and ecological issues. This study explores the engineering properties of waste plastic and quarry dust composite for sustainable infrastructural development. The polyethylene terephthalate type of plastic (PET) was employed, and which was melted and mixed with QD at different compositions of 1:0, 1:1, 1:2, and 1:3 respectively. The influence of the varying compositions on the morphological and engineering properties of resulting WPB composite was investigated. The scanning electron microscopy image showed that WPB composite with higher percentage of QD possess lesser pore space, and which influenced the high strength values. The findings showed P&QD 1:3 have highest compressive strength value of 20.1MPa, and which meets up with the American Concrete Institute and South African standard minimum requirement of 17MPa for structural lightweight concrete applicable for walkways, walling and water retaining structures constructions.

Constitutive and fracture behavior of ultra-strong supercrystalline nanocomposites

Supercrystalline nanocomposites are a new class of hybrid and nanostructured materials that can reach exceptional mechanical strength and can be fabricated at low temperatures. Hierarchically arranged, they bridge the gap from the nano- to the macro-scale. Even though their mechanical properties are starting to be characterized, their constitutive behavior is still largely unexplored. Here, the mechanical behavior of supercrystalline nanocomposites of iron oxide nanoparticles, surface-functionalized with oleic acid and oleyl phosphate ligands, is investigated in both bending and compression, with loading–unloading tests. A new bar geometry is implemented to better detect deformation prior to unstable crack propagation, and notched bending bars are tested to evaluate fracture toughness. Micro-mechanical tests result in the values of strength and elastic modulus that are extremely high for supercrystals, reaching record-high numbers in the oleic acid-based nanocomposites, which also show a significant tension–compression asymmetry. The constitutive behavior of both materials is predominantly linear elastic, with some more marked nonlinearities arising in the oleyl phosphate-based nanocomposites. The fracture toughness of both types of nanocomposites, ∼0.3 MPa√m, suggests that extrinsic toughening, associated with both material composition and nanostructure, plays an important role. Fractographic observations reveal analogies with shear and cleavage in atomic crystals. The influence of material composition, nanostructure, and processing method on the mechanical behavior of the nanocomposites is analyzed.

Mechanical properties of a mortar with melted plastic waste as the only binder: Influence of material composition and curing regime, and application in Bamako

In recent years, serious environmental problems induced by plastic wastes have drawn considerable attention across the world and new initiatives have been adopted to recycle plastic wastes into construction materials. One of the promising initiatives is the use of plastic waste as the only binding phase to make concrete/mortar-like construction materials. However, how key engineering properties of concrete/mortar-like materials with melted plastic as the only binder change with material composition and curing conditions are not well known. This paper aims to investigate the effect of curing conditions and granular material size on the mechanical properties (compressive and splitting tensile strengths) of a mortar with melted plastic waste (high density polyethylene (HDPE) and low density polyethylene (LDPE)) as the only binder (MPB: mortar with melted plastic waste binder). Moreover, it presents a study conducted in the city of Bamako (Mali) to evaluate the use of MPB to make interlocking paving blocks for use on non-traffic areas in residential or municipal construction projects. Two curing conditions, namely, air dry at ambient temperature and water curing were used for this research. Moreover, the size of the granular materials (sand and gravel) was varied in order to assess its impact on the properties of the corresponding MPB sample formulations with given plastic content and HDPE/LDPE (H/L) ratio. Granular material size and curing conditions were found to have significant impact on the mechanical strengths of the MPB materials. Regardless of age and H/L ratio, the MPB samples cured in water showed lower strength (compressive and tensile) than the specimens cured at ambient temperature under controlled laboratory conditions, while adding coarse granular materials helped to improve these strength properties. Furthermore, the mechanical performance of the proposed MPB-interlocking paver is superior to that of the interlocking Portland cement-based pavers that are commercially available on the Bamako’s market. Moreover, the cost of the Portland cement-less MPB-paver will be substantially lower than that of the Bamako’s commercial Portland cement-paver. The obtained results place this MPB material as a promising candidate for making interlocking pavers or other products, while reducing the amount of plastic waste to be managed and the cost of interlocking pavers.

Time-dependent behavior of porous curved nanobeam

This work provides a comparative analysis of the effect of nanovoids distribution associated with trigonometric functions on forced mechanical characteristics of functionally graded curved nanobeams. A geometrically exact model is developed for the simply-supported beam utilizing a higher-order beam theory including thickness stretching effect. In order to capture the small-scale effects, the governing motion equations are integrated with the general strain gradient theory. The virtual work statement of Hamilton principle is adopted to gain the governing equation as well as boundary conditions. Then, Navier solving procedure-based Fourier series is exerted for stating the reference surface displacements of the nanobeam. The numerical examples are expanded to know the behave of transverse deflection, axial, normal, and shear stresses which are highlighted by time under the influence of material composition, porosity coefficient and its distribution patterns, small-scale coefficients as well as geometrical parameters. It is manifested that in a periodic domain, the oscillation amplitudes grow smaller extremely by raising the excitation frequency, while the repetition of them increases.

A Review on Ceo2‐Based Electrocatalyst and Photocatalyst in Energy Conversion

The activation and conversion of small molecules (H2, O2, H2O, CO2, N2, CH3OH, and C2H5OH) in energy‐related systems has attracted researchers’ attentions around the world. The conversion of these molecules plays a key role in renewable energy storage and conversion systems, and for that, the electrocatalysis and photocatalysis processes are considered as clean and efficient strategies. Numerous materials are designed to promote the conversion process to satisfy the different requirements for efficiency and selectivity. Due to the flexible switching between Ce3+ and Ce4+ with rich oxygen defects, CeO2‐based materials display excellent performance in all the related reaction processes. Herein, the CeO2‐based electro(photo)catalysts according to different reactions are summarized. Specifically, the influence of material compositions, morphologies, and structures on catalytic performance is discussed, and the significant role of CeO2 is emphasized. Finally, several approaches are advocated to promote the development of CeO2‐based electro(photo)catalysis and accelerate their industrial application.

Material and Geometric Aspects of SB4 Spring Clips Affecting Their Performance

The article describes the requirements for SB4-type rail spring clips applied for railways before the spring clips are officially approved for use. Two basic aspects of spring clips are discussed: i.e. the material aspect (chemical composition, heat treatment, microstructure, and decarburization) and the aspect of geometric shape. Both of these aspects have a major impact on the performance of the end product. The article features examples of measurement results concerning selected dimensions of a batch of spring clips that did not meet the applicable requirements. It is an introduction to a series of publications presenting research on the influence of material composition and geometry of a product on its clamping force, stiff ness, elasticity curve, and assembly strength. Keywords: rail fastening, spring clip, dimensional measurements, hardness tests

Research on in-situ observation system of seabed boundary layer based on self-potential measurement

The submarine boundary layer is a dynamically changing strip located near the seabed interface. The dynamic change process involves the resuspension and redeposition of sediments, which has an important impact on the transportation of seafloor sediments and the transport of offshore chemical substances. Based on the self-developed self-potential monitoring device, the stability of the device and the characteristics of the seabed and the bottom layer of the sea floor with different textures were tested through laboratory experiments. The results show that the self-developed self-potential monitoring probe has high corrosion resistance, good electrode stability, and guaranteed measurement accuracy. The self-potential measurement can clearly identify the position of the seabed interface, and can judge seabed sediments by positive and negative anomalies. Nature, the sandy seabed is negative anomaly (about -8 mv), the clayey seabed is positive anomaly (about 10 mv). The concentration of solid suspended particles in the seawater and the self-potential difference between the seawater and the seabed appear relatively good linear relationship, the smaller the difference, the greater the concentration of solid suspended particles. The re-deposited sediment changes its self-potential under the influence of material composition and pore structure, but this effect gradually decreases as the consolidation time increases. Therefore, the spontaneous potential measurement can better reflect the dynamic changes of the seafloor sediments, and effectively monitor the dynamic changes of the seafloor boundary layer. It provides a new method for the in-situ observation of the dynamic changes of the submarine boundary layer.

Modeling and simulating the effects of a general imperfect interface in fibrous piezoelectric composites

Interfacial behavior within fibrous piezoelectric composites (PZCs) may dramatically degrade the overall electromechanical performance and simultaneously vary the effective coupling moduli of these intelligent materials. In the present paper, we first recapitulate a physics-based general interfacial relation, which is rigorously derived from an ideal three-phase configuration and thus owns explicit physical meaning, to characterize this behavior between two different piezoelectric media. Afterwards, the explicit strong and weak governing equations of fibrous PZC boundary value problems (BVPs) are constructed, and a computational approach is then developed with the help of the extended finite element method (XFEM) to account for the discontinuities within both the primary (i.e., the electric potential and displacement fields) and the secondary fields (i.e., the normal electric displacement and normal traction fields). To achieve a benchmark problem with analytical exact solution, a simplified general interfacial relation is introduced, and a fibrous PZC BVP involving a cylindrical simplified general interface is designated and analytically solved. Hereafter, the convergence performance and validity of the elaborated computational approach are tested in detail. Eventually, discussions are further made on the influence of material composition and inhomogeneity shapes on the electroelastic coupling behavior of PZCs, and a few concluding remarks are drawn.

Influence of material composition on buckling response of FG plates using a simple plate integral model

In this study, a simple two-dimensional deformation model is employed for buckling analysis of functionally graded (FG) plates. The proposed theory has a kinematic with integral terms which considers the influence of deformation without using shear correction factors. The impact of varying material properties and volume fraction of the constituent on buckling response of the FG plate is examined and discussed. The benefit of this theory over other contributions is that a number of variables is reduced. The basic equations that consider the influence of transverse stresses are derived from the principle of virtual displacements. The analytical solutions are obtained utilizing the Navier method. The accuracy of the proposed theory is proved by comparisons with the different solutions found in the literature.

Influence of Material Composition on Structure, Surface Properties and Biological Activity of Nanocrystalline Coatings Based on Cu and Ti

In this paper, the influence of material composition on structure and surface properties of bioactive coatings based on Cu and Ti is described. Nanocrystalline coatings were prepared by innovative pulsed DC magnetron sputtering. For their preparation, a multi-magnetron system was used in order to obtain films with various copper content. The main goal of our work was the complex analysis of biological activity of Cu-Ti films in comparison with their material composition and surface state. Antimicrobial activity (for E. coli and S. aureus), as well as the impact on cell viability (L929 line), were investigated. The physicochemical properties were examined with the aid of X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and atomic absorption spectroscopy. It was found that all prepared films were nanocrystalline and bactericidal, but their cytotoxicity was related to the Cu-content in the film. Complex analysis of the bioactivity was developed in relation to the copper ion migration process. Moreover, manufacturing of antibacterial films with stimulating action on L929 cell line was possible.

Carbonate Apatite Micro-Honeycombed Blocks Generate Bone Marrow-Like Tissues as well as Bone.

Hematopoietic stem cells form blood cells in bone marrow and reside in niches. Artificial environments that conserve these niches may generate bone marrow. Osteogenesis, angiogenesis, and material resorption must be regulated to create these environments. These processes are controlled by material composition and macro- and microporous structures. Here, three blocks with different micropore structures are fabricated. Carbonate apatite has nearly the same composition as natural human bone and their honeycomb structure facilitates cell penetration and survival. In samples with high microporosity, endosteum-like tissues such as sinusoids form in areas of material resorption and high local calcium concentration. These conditions resemble environments conducive to niche maintenance. Bone marrow-like tissues and megakaryocytes are successfully generated in this environment. Micropore structure is the most critical factor in bone marrow formation; however, the influences of material composition and macropore structure must also be considered. The results of this study may help develop treatments for bone marrow-related diseases and elucidate the components and functions of the hematopoietic stem cell niche.

Tailoring optical and electrical properties of thin-film coatings based on mixed Hf and Ti oxides for optoelectronic application

In this work multi-magnetron sputtering stand was used for the deposition of the mixed oxides thin films based on HfO2 and TiO2. In order to obtain various material composition the power released to each magnetron (containing metallic hafnium and titanium targets) was precisely selected. Structural, surface, optical, electrical and mechanical properties of as-deposited coatings were analyzed. Depending on the hafnium content in the deposited thin films various types of the microstructure was obtained, i.e. HfO2-monoclinic, amorphous and TiO2-rutile. Increase of Ti content above 28at. % in the as-prepared mixed oxides coatings caused their amorphization. It was found that with an increase of Ti content in prepared coatings their surface roughness and simultaneously water contact angle decreased. Performed measurements of electrical properties revealed that the lowest leakage current density in the range of 10−7–10−8A/cm2 was obtained for amorphous coatings. Moreover, the tailoring of the dielectric constant was possible by a proper selection of material composition and microstructure of the deposited thin films. Average transparency in the visible wavelength region was in the range of ca. 79–86%. The influence of material composition and structure on shifting of the fundamental absorption edge and optical band gap energy was also observed. The refractive index increased with an increase of Ti content, while extinction coefficient was the lowest for amorphous coatings. Additionally, hardness values were dependent on the material composition and optical packing density and were in the range from 7.6GPa to 10.1GPa.

The impact of reaction conditions and material composition on the stepwise methane to methanol conversion over Cu-MOR: An operando XAS study

The direct methane to methanol (DMTM) conversion is often referred to as a ‘dream reaction’ with enormous potential to alter energy sector and chemical industry. After O2-activation, Cu-exchanged zeolites form CuxOy species that activate CH4 and release it in the form of CH3OH upon interaction with H2O. Despite extensive research efforts in the last years, several questions concerning the influence of materials composition and process parameters on the reaction mechanism remain open. Herein, we characterize Cu-MOR zeolites with different composition by operando X-ray absorption spectroscopy (XAS), monitoring their spectroscopic response under two characteristic DMTM reaction protocols varied in the duration of the key reaction steps. Linear Combination Fit (LCF) analysis of the time-resolved X-ray absorption near edge structure (XANES) spectra collected during CH4-loading and steam-assisted CH3OH extraction enabled to quantify the abundance of different Cu species during these two steps. Data analysis revealed a positive linear correlation between the methanol yield generated per incorporated copper and the Cu(I) component formed during the CH4-loading step. Cu(I) development during CH4-loading is accompanied by modifications in the extended X-ray absorption fine structure (EXAFS) spectra suggesting substantial rearrangement in the active site structure. The obtained results provide new mechanistic insights for the DMTM over Cu-MOR.