Similar Materials Research Articles

Geotechnical Model Testing with High-Strength Gypsum Similar Materials: A Case Study on Quartzite-Like Formulations

This paper explores the formulation and optimization of high-strength gypsum-based similar materials for geomechanical model tests, with a specific focus on their application in simulating conditions analogous to quartzite. Employing an orthogonal experimental design, key factors such as quartz sand-to-gypsum ratio, cement-to-gypsum ratio, and barite content were systematically varied. Through a series of indoor experiments, comprehensive assessments of physical and mechanical properties, including density and compressive strength, were conducted for diverse material ratios. The results reveal a broad spectrum of physical and mechanical indicators, aligning with the requisites for model tests across varying similarity ratios. Notably, a high-strength gypsum formulation yielding a uniaxial compressive strength within the precise range of 10~20 MPa was identified, providing valuable insights for researchers engaged in hard rock model tests using similar materials. The study underscores the influential roles of barite content, quartz sand-to-gypsum ratio, and cement-to-gypsum ratio on the density and compressive strength of similar materials. This research contributes essential data for the application of high-strength gypsum in geotechnical model testing, particularly in replicating the mechanical behavior of quartzite.

Comparative study on liquid versus gas phase hydrochloric acid hydrolysis for microcrystalline cellulose isolation from sugarcane bagasse

Microcrystalline cellulose (MCC) was successfully synthesized from sugarcane bagasse using a rapid, low-temperature hydrochloric acid (HCl) gas treatment. The primary aim was to develop an energy-efficient “green” cellulose extraction process. Response surface methodology optimized the liquid-phase hydrolysis conditions to 3.3 % HCl at 117 °C for 127 min to obtain MCC with 350 degree of polymerization. An alternative gas-phase approach utilizing gaseous HCl diluted in hot 40 °C air was proposed to accelerate MCC production. The cellulose pulp was moistened to 15–18 % moisture content and then exposed to HCl gas, which was absorbed by the moisture in the cellulose fibers to generate a highly concentrated acidic solution that hydrolyzed the cellulose. The cellulose pulp was isolated from depithed bagasse through soda pulping, multistage bleaching and cold alkali purification. Hydrolysis was conducted by saturating the moist cellulose fibers with gaseous HCl mixed with hot air. Extensive analytical characterization using FT-IR, XRD, SEM, TGA, DSC, particle size, and porosity analyses verified comparable physicochemical attributes between MCC samples prepared via liquid and gas phase methods. The gas-produced MCC revealed 85% crystallinity, 71 Å crystallite dimensions, and thermally stable rod-shaped morphology with an average diameter below 200 μm. The similar material properties validate the proposed gas-based technique as an equally effective yet more energy-efficient alternative to conventional aqueous acid hydrolysis for fabricating highly pure MCC powders from lignocellulose. This sustainable approach enables the value-addition of sugarcane bagasse agro-industrial residue into cellulosic nanomaterials for wide-ranging industrial applications. In summary, the key achievements of this work are rapid MCC production under mild temperatures using HCl gas, optimization of liquid phase hydrolysis, successful demonstration of gas phase method, and extensive characterization verifying equivalence between both protocols. The gas methodology offers a greener cellulose extraction process from biomass.

Composition dependence of oxidation resistance in high entropy ultra-high temperature ceramics

High entropy ultra-high temperature ceramics (HE-UHTCs) have garnered intense research interest due to the potential for optimized oxidation and mechanical properties for extreme environment applications. HE-UHTCs are expected to oxidize according to the thermodynamic favorability of their respective oxidation reactions, which varies according to the periodic grouping. Based on this, the oxidation resistance of equimolar (metals-basis) group IV + V (HfZrTiTaNb), group IV + V + VI (HfZrTiTaMo) and group IV + VI (HfZrTiMoW) carbides and borides were evaluated at 1700°C in 1 mol% O2 for 5 min and compared. Group IV elements oxidized preferentially in all three compositions. Group V element-containing carbides exhibited the lowest oxidation resistance, attributed to the formation of intergranular liquid oxides. (HfZrTiMoW)C exhibited the best resistance among the carbides. The diborides exhibited similar material consumption, reinforcing the hypothesis that the oxidation behavior under these conditions is controlled by the presence of boria. These findings provide direction for HE-UHTC composition design for oxidation resistance.

Influence of Ni and PWHT on microstructure evolution and mechanical properties of GTA-welded duplex stainless steel and super duplex stainless steel joints: A comparative investigation

In the present investigation, a new endeavor has been made to analyze the impact of the secondary process (post-weld heat treatment (PWHT)) as well as Ni addition on the microstructure and mechanical characteristics of welds. Welds between similar joining materials from duplex stainless steels (DSS), as well as super DSS (SDSS), were made by the gas tungsten arc welding (GTAW) process. For DSS, after PWHT with the addition of Ni element, the amount of austenite rises and becomes more uniformly distributed with curved boundaries, while for SDSS, the microstructure mainly consists of intergranular and Widmanstätten austenite. According to the comparison of phase percentages obtained based on both ASTM E1245 and ASTM E562, a good balance between ferrite and austenite phases of joint materials was achieved. X-ray diffraction analyses on both joints revealed that phases are mainly ferrite and austenite with different lattice parameters without evidence of unwanted intermetallic phases. The addition of Ni increases the hardness values of DSS weld metal compared to the base metal due to an increased amount of Widmanstätten austenite and ferrite in the microstructure. The lowest ductility was obtained for the SDSS weld sample with the addition of Ni and PWHT because of the existence of secondary austenite in the weld metal and the Widmanstätten morphology of the austenite. The effect of PWHT on the development of microstructure and mechanical behaviors was more than the effect of nickel powder on weld samples.

Survey and preliminary assessment of a baroque vault for refurbishment planning

Abstract Designing the modification of buildings for a new use is a costly and time-consuming process, before which it is often necessary to conduct a preliminary assessment of the feasibility of the intended project. The article discusses the procedure for such a preliminary cost-effective assessment using the example of a historic building with vaulted ceilings. For older historical buildings, archival documents specifying their geometry, construction details and material characteristics are typically not available. For the preliminary design, it is possible to obtain information about the dimensions of the load-bearing elements non-destructively. However, the knowledge of the exact material properties of the masonry exceeds the possibilities of an inexpensive assessment, which must take advantage of the data available in the literature for similar structures. This article presents a methodology and an example of the measurement and assessment of the mechanical response of the Baroque vault to static loading. It shows the process of obtaining data on the geometric shape of the structure by means of geodetic surveying and geometric radar measurements of the thickness of vaults whose upper faces are not accessible. Two models are used to calculate the internal forces in the structure. The first planar model considers a simplified barrel vault strip according to the focused geometry with respect to geometric nonlinearity and without tension, the second model is a linear spatial model of the entire vault. The calculation was performed in ANSYS 17.2, the input parameters of the material are taken from the literature. The calculated stresses in the vault are compared with the values of the design strength of brick masonry, taking into account the characteristic compressive strength of the masonry based on published known data obtained during tests of similar historical materials. The results are then used to decide on the feasibility of the intention to adapt the building for a new use.

QUALITY ASSESSMENT OF SILYBUM MARIANUM FRUITS GROWN IN THE REPUBLIC OF BURYATIA

Introduction. Medicines of plant origin are widely used in the complex therapy of various diseases. Among the medicines of plant origin used for the treatment of chronic liver diseases, the most popular are preparations based on Silybum marianum (L.) Gaertn.). The aim of this work was to Silybum marianum fruits to evaluate the possibility of obtaining raw materials of pharmacopoeial quality in the dry-steppe zone of the Republic of Buryatia. Material and methods. The object of the study was Silybum marianum fruits of the varieties Debut and Start, obtained from experimental fields in Ivolginsky district of the Republic of Buryatia, as well as samples of Silybum marianum fruits received for analysis at the Testing Center of FGBNU VILAR from different regions of the Russian Federation. Results. As a result of the research it was found that climatic and geographical conditions of the dry-steppe zone of the Republic of Buryatia allow successful cultivation of Silybum marianum and obtaining raw materials (fruits) of pharmacopoeial quality. Conclusion. Silybum marianum fruits obtained from plants of the Start variety are not inferior to similar raw materials harvested in other regions of the Russian Federation in the content of the sum of flavolignans.

Deep learning-based data processing method for transient thermoreflectance measurements

Pump–probe thermoreflectance has been commonly applied for characterizing the thermal properties of materials. Generally, a reliable and efficient non-linear fitting process is often implemented to extract unknown thermal parameters during the pump–probe thermoreflectance characterizations. However, when it comes to processing large amounts of data acquired from similar structural samples, non-linear fitting process appears to be very time-consuming and labor-intensive to search for the best fitting for every testing curve. Herein, we propose to apply deep learning (DL) approach to nanosecond transient thermoreflectance technique for high-throughput experimental data processing. We first investigated the effect of training set parameters (density and bounds) on the predictive performance of the DL model, providing a guidance to optimize the DL model. Then, the DL model is further verified in the measurement of the bulk sapphire, SiC, diamond samples, and GaN-based multilayer structures, demonstrating its capability of analyzing the results with high accuracy. Compared to the conventional non-linear fitting method (such as Global Optimization), the computation time of the new model is 1000 times lower. Such a data-driven DL model enables the faster inference and stronger fitting capabilities and is particularly efficient and effective in processing data acquired from wafer-level measurements with similar material structures.

Tunable and stable micro-ring resonator based on thin-film lithium tantalate

As ferroelectric materials, lithium tantalate and lithium niobate share similar material characteristics, such as a high Pockels effect and nonlinear optical coefficients. When compared to lithium niobate, lithium tantalate offers a higher optical damage threshold, a broader transparent window, and lower birefringence, making it a promising candidate for high-performance electro-optical photonic integrated devices. In this study, we design and successfully fabricate micro-ring resonators on an acoustic-grade lithium-tantalate-on-insulator wafer, demonstrating their tunability and dynamic modulation capabilities. Experimental results indicate that the achieved thin-film lithium tantalate based micro-ring resonator exhibits an intrinsic Q-factor of 8.4 × 105, corresponding to a waveguide propagation loss of 0.47 dB/cm and a tuning efficiency of 1.94 pm/V. More importantly, as compared to those based on thin-film lithium niobate, a much weaker photorefractive effect and drift phenomenon around the 1550 nm wavelength under a direct-current drive are observed in the present fabricated thin-film lithium tantalate micro-rings with a silicon oxide over-cladding and a tuning electrode on top.

Slow dynamics and the role of moisture

The elastic behavior of rocks and other composite materials cannot be entirely captured by the traditional theory of nonlinear elasticity, where the stress field is related to powers of the strain field. Rather, these materials display non-classical nonlinear elastic behavior, such as hysteresis, end-point memory, fast dynamics, and slow dynamics. Slow dynamics (SD) is characterized by a drop in material stiffness due to a minor mechanical conditioning, followed by a slow recovery back to the original macroscopic elastic state. SD has drawn particular attention because the recovery, often logarithmic in time, has been observed in a wide variety of materials, on lengths scales from the laboratory to the seismic, and on time scales from milliseconds to years. The universal character suggests a simple, fundamental mechanism for the SD recovery. This talk will present recent experiments that seek to test proposed SD mechanisms. In particular, the role of moisture will be investigated. The main experimental venue is the simplified structure introduced in previous work—a single bead confined between two slabs of a similar material. The main benefit of this structure over more commonly studied SD materials (sandstones and concrete) is the ability to control the environment around the contact points.

Electrical and structural engineering of nanoflower-like NiMn-layered double hydroxide by V modulation for high-performance hybrid supercapacitors

This work produced V-doped NiMn-layered double hydroxide(V-NiMnLDH) composite positive electrode material directly on nickel foam using a simple one-step hydrothermal synthesis process. The composite's 3D nanoflower-like design increased spatial utilization, surface area, and active sites for Faradaic redox reactions. The composite material has a specific capacitance of 1551 F g−1 at 1 A g−1 and 85.6 % capacitance retention at 10 A g−1, demonstrating exceptional cycle stability. In addition, we combined V-NiMnLDH with commercial activated carbon to create an asymmetric supercapacitor (ASC) with 63.5 Wh kg−1 energy density and 975 W kg−1 power density. After 5000 charge-discharge cycles, the gadget preserved 89.7 % of its specific capacitance. This material outperforms similar electrode materials in certain performance evaluations. We also used density functional theory (DFT) computations to analyze each element in the V-NiMnLDH composite and explain their electronic density of states contributions. This theoretical framework explains how V doping improves capacitance. Band structure simulations also showed V-NiMnLDH's higher charge transfer and conductivity compared to intermediate products, explaining its extraordinary capacitance performance. Our work combines theoretical and experimental data to advance catalyst design and high-performance energy storage materials.

Cementation breaking and grit separation characteristics of weakly cemented natural gas hydrate by a new structure hydrocyclone

Solid fluidization exploitation technology is one of the most promising methods for the safe exploitation of shallow natural gas hydrates (NGH) in the deep sea. However, after primary jet breaking in the solid fluidization exploitation, the hydrate and argillaceous silt particles are in a state of weak cementation and agglomeration. When the argillaceous silt particles enter the offshore drilling platform with the drilling fluid, it causes substantial sand production, high energy consumption, and pipeline blockage, considerably affecting the development process of the NGH test. Therefore, in-situ desanding has become one of the key technologies of solid fluidization exploitation. In this study, a coupling method of hydrocyclone cementation breaking and hydrocyclone desanding was proposed, and a new structure of cementation breaking and grit separation hydrocyclone was designed. In a lab-designed cementation breaking and grit separation hydrocyclone system, the cementation breaking and grit separation characteristics of weakly cemented NGH similar materials in the swirl flow field were studied. The experimental results under the operating conditions studied show that the swirl flow field exhibits good cementation breaking and grit separation performance for weakly cemented NGH similar materials. For weakly cemented NGH similar materials with a compressive strength of 0.06–0.42 MPa, the cementation breaking efficiency of the cementation breaking and grit separation hydrocyclone is in the range of 27.17–99.61%. After the cementation breaking, the mixture of hydrate similar materials (hydrophilic polyethylene powder) and quartz sand was separated in the hydrocyclone. The separation efficiency of hydrate similar materials is 27.59–99.64%, and the desanding efficiency is 87.66–99.98%. The cementation breaking and grit separation of weakly cemented NGH similar materials were successfully realized. Based on the experimental data, a multiple regression model for the cementation strength of similar materials and the swirl flow field strength was established using the least squares method. This method is expected to provide new technical support for in-situ desanding and safe exploitation of the deep-sea shallow NGH production process.

Review on Laser Welding Technology on Aluminum and Copper Dissimilar Materials for Secondary Batteries Assembly

Electric vehicles have recently taken center stage, driven by growing environmental concerns, with a key focus on ensuring the reliability of their batteries. The materials used in the electrical connections of secondary batteries predominantly consist of Al and Cu alloys, necessitating the joining of both similar and dissimilar materials. This paper presents a technical review on laser welding technology applied to the challenging Al/Cu dissimilar metal combination. The complexity arises from the formation of brittle phases in intermetallic compounds and the low absorption of laser beams by the base materials. The characteristics of various laser welding modes and their effective monitoring through deep learning are explained in detail. The development of real-time laser welding monitoring technology is crucial to increase productivity and enable the mass production of reliable electric vehicle battery systems.

Применение Chat GPT для создания учебных материалов по английскому языку для детей младшего школьного возраста

Nowadays there is a tendency of implementing artificial intelligence in various fields, including education. Lan-guage models, including Chat GPT, are mainly used for working with such monotonous tasks as checking homework, writing and assessment tasks. The implementation of AI has certain advantages (finding individual approach, fast and detailed feedback, etc.) and disadvantages (overdependence on the technology, academic cheating, etc.). This article examines the use of the above language system for generating English grammar exercises in order to introduce them into the educational process when working with primary school students in comparison with the use of similar material from traditional grammar books. The study revealed the absence of significant differences between exercises from grammar books and those created by the artificial intelligence.

Water vapour permeability of inorganic construction materials

Water vapour permeability (WVP) data on brick, stone, plaster and cement-based materials from some seventy publications are reviewed and assessed. Almost all sources use standard cup-test methods or close variants. Comparisons of WVP values from different sources on similar materials confirm that reproducibility between different laboratories is poor. Some deficiencies of cup-test methods are discussed, including uncertainties arising from the use of saturated-salt humidistats and desiccants. There is evidence that the water vapour resistance factor decreases as volume-fraction porosity increases, and data support a simple porosity–tortuosity relation. Data also show that the resistance factor decreases with increasing mean relative humidity across the test specimen, with the wet-cup value consistently lower than the dry-cup values for a given material. The contribution of liquid film flow to mass transfer is discussed. It is shown how film thickness and film-flow permeability may be estimated from the water-vapour sorption isotherm; and a related regression equation is developed It is concluded that available data are inadequate to establish the fundamental physics of WVP; vapour-only permeability data for engineering purposes should be obtained in dry-cup tests at low humidity; and research studies should aim to integrate the WVP into the framework of unsaturated flow theory.

Modelling photoperiod in enhancing hydrogen production from Chlorella vulgaris sp. while bioremediating ammonium and organic pollutants in municipal wastewater

Municipal wastewater is ubiquitously laden with myriad pollutants discharged primarily from a combination of domestic and industrial activities. These heterogeneous pollutants are threating the natural environments when the traditional activated sludge system fails sporadically to reduce the pollutants' toxicities. Besides, the activated sludge system is very energy intensive, bringing conundrums for decarbonization. This research endeavoured to employ Chlorella vulgaris sp. In converting pollutants from municipal wastewater into hydrogen via alternate light and dark fermentative process. The microalgae in attached form onto 1 cm3 of polyurethane foam cubes were adopted in optimizing light intensity and photoperiod during the light exposure duration. The highest hydrogen production was recorded at 52 mL amidst the synergistic light intensity and photoperiod of 200 μmolm−2s−1 and 12:12 h (light:dark h), respectively. At this lighting condition, the removals of chemical oxygen demand (COD) and ammoniacal nitrogen were both achieved at about 80%. The sustainability of microalgal fermentative performances was verified in recyclability study using similar immobilization support material. There were negligible diminishments of hydrogen production as well as both COD and ammoniacal nitrogen removals after five cycles, heralding inconsequential microalgal cells’ washout from the polyurethane support when replacing the municipal wastewater medium at each cycle. The collected dataset was finally modelled into enhanced Monod equation aided by Python software tool of machine learning. The derived model was capable to predict the performances of microalgae to execute the fermentative process in producing hydrogen while subsisting municipal wastewater at arbitrary photoperiod. The enhanced model had a best fitting of R2 of 0.9857 as validated using an independent dataset. Concisely, the outcomes had contributed towards the advancement of municipal wastewater treatment via microalgal fermentative process in producing green hydrogen as a clean energy source to decarbonize the wastewater treatment facilities.

Feasibility Study of Material Deformation and Similarity of Spatial Characteristics of Standard Coal Rocks

The comparison between similar materials and original coal rock is the basis for similar simulation experiments in coal mines. The differences in mechanical properties, acoustic characteristics, and damage laws between similar materials and the original coal rock are of great significance for similar simulation research, to reveal objective laws. First, materials similar to coal rock with similar theoretical ratios were taken as the object of research, and the sand–cement ratio, the carbon paste ratio, and the water content were determined by multivariate linear regression to accurately match the ratios. Second, by using acoustic emission and digital scattering technology to explore the acoustic law, deformation characteristics, and spatial feature similarities of the materials similar to coal rock, the acoustic emission evolution law of the original rock was found to be the same as that of the similar materials. Digital scattering was able to describe the localization of strain in the similar materials, and the correlation between the overall deformation and the local deformation was explored. This indicates that materials similar to coal rock can effectively simulate the deformation of actual coal rocks. Lastly, these materials were found to allow effectively simulating the deformation characteristics and spatial properties of actual coal rock, which provides an important experimental means and method for similar research in the field of coal rock engineering.

Research on the ratio of similar materials in water-absorbent mudstone based on fuzzy mathematics.

To determine the suitability and credibility of similar water-absorbent mudstone materials in model experiments, the prototype mudstone parameter similarity index was determined based on the similarity theory. Similar materials use cement and Plaster as binders and quartz sand as aggregate. The sensitivity of similar indicators of similar materials to control factors was analyzed through range statistics. Multiple regression analysis was used to establish the quantitative relationship between each control factor and similar indicators. Finally, the optimal matching scheme was refined through the combination of fuzzy mathematics and analytic hierarchy process. The results show that the physical and mechanical property indicators of similar materials with different proportions have a wide distribution range, and under certain similar conditions, they can meet the requirements of rock model tests with different properties. The aggregate-binder ratio is a direct indicator of material density, elastic modulus, and compressive strength. The main controlling factors, material density, elastic modulus, and compressive strength all increase with the decrease in aggregate-binder ratio. The cement-plaster ratio is the main control factor of material water absorption, and the water absorption gradually decreases with the increase of the cement-plaster ratio. The formula obtained through linear analysis can better represent the changing trend and distribution characteristics of various parameters of similar materials with the aggregate-binder ratio and cement-plaster ratio, and initially optimize the proportioning scheme of similar materials. Use fuzzy mathematics to evaluate the membership degree of each parameter index of similar materials, and the optimal ratio scheme was further determined to improve the credibility of later model experiments.

Platform visibility and the making of an issue: Vernaculars of hereditary cancer on Facebook, Instagram, TikTok and Twitter

We investigate the relationship between platform visibility and meaning making. Drawing on a quanti-quali investigation of hashtag practices in a cross-platform dataset, we explore how hereditary cancer is constructed, as an issue, on social media. Our findings provide strong evidence of significant variations across Instagram, TikTok and Twitter, with hashtag practices on these platforms tapping into platform-specific understandings of hereditary cancer: a pink ribbon issue on Instagram, the opportunity for non-normative exposures of bodies, pain and acceptance on TikTok and a scientific matter on Twitter. Platforms do not dictate choice, but their encounter with user interpretations, given similar material constraints (hashtag technology), lead to very different affordances. These affordances shape practices and, ultimately, meaning making. While raising concerns on the impact platform visibility might have on experiences and understandings of hereditary cancer, our work suggests broader implications for how we imagine and respond to the issues we care about.

Smith–Watson–Topper Parameter in Partial Slip Bimodal Oscillations of Axisymmetric Elastic Contacts of Similar Materials: Influence of Load Protocol and Profile Geometry

Based on a very fast numerical procedure for the determination of the subsurface stress field beneath frictional contacts of axisymmetric elastic bodies under arbitrary 2D oblique loading, the contact mechanical influences of loading parameters and contact profile geometry on the Smith–Watson–Topper (SWT) fatigue crack initiation parameter in elastic fretting contacts with superimposed normal and tangential oscillations are studied in detail. The efficiency of the stress calculation allows for a comprehensive physical analysis of the multi-dimensional parameter space of influencing variables. It is found that a superimposed normal oscillation of the contact can significantly increase or decrease the SWT parameter, depending on the initial phase difference and frequency ratio between the normal and tangential oscillation. Written in proper non-dimensional variables, the rounded flat punch always exhibits smaller values of the SWT parameter, compared to a full paraboloid with the same curvature, while the truncated paraboloid exhibits larger values. A small superimposed profile waviness also significantly increased or decreased the SWT parameter, depending on the amplitude and wave length of the waviness. While both the load protocol and the profile geometry can significantly alter the SWT parameter, the coupling between both influencing factors is weak.

Influence of the confinement effect by a sandwiched subnanoreactor on the electrocatalytic performance for the nitrogen reduction reaction

Nanoconfinement effect allows precise tuning of catalyst performance by providing a spatially confined (sub)nanoscale environment for reaction systems. For the confined catalysts constructed from two-dimensional materials and transition metals, it can be achieved experimentally by wrapping metal nanoparticles in layers of carbon or other similar materials. Here, we propose a new type of confined catalyst composed of iron clusters sandwiched between graphitic carbon nitride and black phosphorus monolayers, and investigate its performance in the nitrogen reduction reaction by first-principles simulations. It is found that the overpotential at the Fe active site exhibits a significant decrease from 0.82 V to 0.49 V after the formation of the confined interfacial microenvironment, which is attributed to the spatial confinement by the two-dimensional monolayers and the change in binding patterns between the adsorbed species and the iron cluster. The corresponding selectivity in competition with the hydrogen evolution reaction is also improved to a certain extent. Moreover, the appearance of electronic states of the black phosphorus overlayer at the Fermi level further promotes the carrier transport in the electrochemical processes. Our work demonstrates the role of the nanoconfinement effect in enhancing the electrocatalytic performance and may shed new light on the rational design of electrocatalysts.