Solution Composition Research Articles

Influence of silica on the crystallization of sodium hydroaluminate

To extract aluminium from highly concentrated aluminate solutions of alumina-containing raw materials, decomposition is performed through the crystallization of sodium hydroaluminate. This paper presents the results of a study on the stability of aluminate solutions. To calculate the probable yield of Al2O3 in the solid phase, it is necessary to determine the crystallization rate of sodium hydroaluminate according to the composition of the initial solutions and the conditions of the process. The influences of SiO2 content on the decomposition of aluminate solutions with Na2Ok concentrations of 540 g/dm3 and 590 g/dm3 with and without inoculum were studied. In addition, the influence of silica on the appearance of precipitating crystals of sodium hydroaluminate was considered. A sharp increase in the stability of the aluminate solutions at rest in the presence of silica was observed. Different crystallization conditions for sodium hydroaluminate have been investigated. Silica slows the crystallization process of sodium hydroaluminate, affecting both the nucleation and crystal growth rates. The effect of SiO₂ on the rate of decomposition is similar to the reduction in the degree of supersaturation.

Change of solution composition during it migration through the sedimentary cover in the center of the modern hydrothermal system (Juan de Fuca Ridge, Pacific Ocean, Hole ODP 858B)

Change of solution composition during it migration through the sedimentary cover in the center of the modern hydrothermal system (Juan de Fuca Ridge, Pacific Ocean, Hole ODP 858B)

Ni-B-PTFE Nanocomposite Co-Deposition on the Surface of 2A12 Aluminum Alloy.

The spinning cup, a crucial component of textile equipment, relies heavily on 2A12 aluminum alloy as its primary raw material. Commonly, electroplating and chemical nickel-phosphorus (Ni-P) plating are employed to improve the surface characteristics of the object. Nevertheless, due to the growing expectations for the performance of aluminum alloys, the hardness and wear resistance of Ni-P coatings are no longer sufficient to fulfill industry standards. This study primarily focuses on the synthesis of Ni-B-PTFE nanocomposite chemical plating and its effectiveness when applied to the surface of 2A12 aluminum alloy. We examine the impact of the composition of the plating solution, process parameters, and various other factors on the pace at which the coating is deposited, the hardness of the surface, and other indicators of the coating. The research findings indicate that the composite co-deposited coating achieves its optimal surface morphology when the following conditions are met: a nickel chloride concentration of 30 g/L, an ethylenediamine concentration of 70 mL, a sodium borohydride concentration of 0.6 g/L, a sodium hydroxide concentration of 90 g/L, a lead nitrate concentration of 30 mL, a pH value of 12, a temperature of 90 °C, and a PTFE concentration of 10 mL/L. The coating exhibits consistency, density, a smooth surface, and an absence of noticeable pores or fissures. The composite co-deposited coating exhibits a surface hardness of 1109 HV0.1, which significantly surpasses the substrate's hardness of 232.38 HV0.1. The Ni-B-PTFE composite coating exhibits an average friction coefficient of around 0.12. It has a scratch width of 855.18 μm and a wear mass of 0.05 mg. This coating demonstrates superior wear resistance when compared to Ni-B coatings. The Ni-B-PTFE composite coating specimen exhibits a self-corrosion potential of -6.195 V and a corrosion current density of 7.81 × 10-7 A/cm2, which is the lowest recorded. This enhances its corrosion resistance compared to Ni-B coatings.

Rheology characterization of ionic liquids under high pressure and high temperature

Ionic liquids (ILs) are liquid salts that exist at or below ambient temperatures and are composed of ion pairs. They offer promising alternatives to toxic, hazardous, highly flammable, and volatile solvents in various applications such as solution preparation, dispersion, gel formation, composites, and polymer melts. ILs possess unique and interesting characteristics, including excellent chemical and thermal stability and low vapor pressures. Understanding the rheological properties of ILs is essential to optimizing IL performance. This paper presents a comparative analysis of the rheological properties of two ionic liquids, NHexylpyridinium tetrafluoroborate (HPyBF4) and NHexylpyridinium bromide (HPyBr), under different shear rates, temperatures, and pressures. Rheological measurements were performed under varying controlled pressure and temperature conditions. The experimental investigation covered a pressure range of 689–12,411 kPa [100–1800 psi] and a temperature range from room temperature up to 522 kelvin (K) [480°F]. The primary objective is to explore and compare the flow behavior and viscoelastic characteristics of HPyBF4 and HPyBr under high-pressure and high-temperature conditions. The experimental data showed that HPyBF4 and HPyBr exhibited shear-thinning behavior, and pressure had an insignificant effect on rheology compared to the temperature effect. Under the same testing conditions, HPyBr showed higher shear stress and viscosity than HPyBF4. This research significantly contributes to the improved understanding of the rheological behavior of these specific ionic liquids and their suitability for diverse industrial and scientific applications, particularly in high-pressure and high-temperature environments.

On the role of the porous support membrane in seawater reverse osmosis membrane synthesis, properties and performance

In this study, we explore the role of the polysulfone (PSU) support membrane skin-layer and whole-body pore morphology on the physical-chemical properties and separation performance of hand-cast polyamide-PSU (PA-PSU) composite seawater reverse osmosis (SWRO) membranes. We tailor the support membrane pore morphology by varying the PSU concentration and the coagulation bath temperature. In order to isolate the impacts of the PSU support, all of the porous supports are coated using identical m-phenylene diamine (MPD) and trimesoyl chloride (TMC) solution compositions, reaction conditions, and post-treatments. As PSU concentration increases, PSU support membrane pore size, surface and body porosity, water permeability, MPD mass uptake (by the PSU support), and PA-PSU composite membrane water permeability decrease, while MPD and TMC conversion, PA film mass and thickness, crosslinking degree (XD), and PA-PSU composite membrane NaCl rejection increase. As PSU support membrane coagulation bath temperature increases, support membrane pore size, surface and body porosity, MPD uptake, PA film mass, thickness and XD, MPD and TMC conversion, and NaCl rejection increase, while composite PA-PSU membrane water and NaCl permeability decrease. Composite membrane permeabilities were 70–90 percent of the (theoretical) unsupported PA film permeabilities due to the high XD and low PA coating film thickness. Composite PA-PSU membrane water/salt permeabilities both correlate most strongly with PA coating film mass/thickness and XD, which in turn correlate most strongly with TMC conversion. The key to increasing water permeability is lower PA film mass/thickness and XD with higher support membrane surface pore size and porosity. In contrast, the key to increasing NaCl rejection is higher PA film mass/thickness and XD with lower support membrane surface pore size and porosity.

Exact solution for heat transfer across the Sakiadis boundary layer

We consider the problem of convective heat transfer across the laminar boundary layer induced by an isothermal moving surface in a Newtonian fluid. In a previous work [Barlow et al., “Exact and explicit analytical solution for the Sakiadis boundary layer,” Phys. Fluids 36, 031703 (2024)], an exact power series solution was provided for the hydrodynamic flow, often referred to as the Sakiadis boundary layer. Here, we utilize this expression to develop an exact solution for the associated thermal boundary layer as characterized by the Prandtl number (Pr) and local Reynolds number along the surface. To extract the location-dependent heat transfer coefficient (expressed in dimensionless form as the Nusselt number), the dimensionless temperature gradient at the wall is required; this gradient is solely a function of Pr and is expressed as an integral of the exact boundary layer flow solution. We find that the exact solution for the temperature gradient is computationally unstable at large Pr, and a large Pr expansion for the temperature gradient is obtained using Laplace's method. A composite solution is obtained, which is accurate to O(10−10). Although divergent, the classical power series solution for the Sakiadis boundary layer—expanded about the wall—may be used to obtain all higher-order corrections in the asymptotic expansion. We show that this result is connected to the physics of large Prandtl number flows where the thickness of the hydrodynamic boundary layer is much larger than that of the thermal boundary layer. The present model is valid for all Prandtl numbers and attractive for ease of use.

Composite Iodine-gold Nanoparticles as a Contrast Agent in Computed Tomography.

Solutions of iodine-based compounds, due to their high X-ray attenuation coefficient, are widely used as contrast agents in computed tomography (CT) imaging. This paper investigates the attenuation properties of iodine and gold to develop nanoparticle-based contrast agents, for example, composite nanoparticles (NPs) with layers of iodine and gold or a mixture of NPs of gold and iodine. A theoretical formula is derived that gives the Hounsfield Unit (HU) for different weight-by-weight (w/w) concentrations of a mixture of blood + iodine + gold. The range of compositions for which iodine + gold mixture can give a suitable HU ≥250 upon being mixed with blood, is formulated. These estimates are derived from experiments on the variation of HU values in different compositions of aqueous solutions of iodine and available data for gold. It is seen that for an aqueous solution of iodine, the suitable HU of 250 (hence giving sufficient gray level to the CT image) can be obtained with w/w concentrations of iodine being 0.0044, 0.008, and 0.0097 for observations at 80, 100, and 120 kVp, respectively. The corresponding w/w concentrations of gold NPs would be 0.0103, 0.0131, and 0.0158. With these basic results, compositions of suitable mixtures of iodine and gold are also specified. Aqueous suspensions of gold NPs are suitable as contrast materials for CT imaging and can also be used as a component of a composite contrast material consisting of an iodine and gold mixture.

Local strain heterogeneity associated with Al/Si ordering in anorthite, CaAl2Si2O8, with implications for thermodynamic mixing behavior and trace element partitioning in plagioclase feldspars

Abstract Hard Mode IR powder absorption spectroscopy has been used to characterize local strain relaxation associated with Al/Si ordering in a suite of synthetic anorthite samples with structural states that vary from a high degree of Al/Si order through a metastable incommensurate structure at intermediate states of order to long-range order with I1 symmetry. The dominant feature accompanying the changing structural states is line broadening, which has been quantified by autocorrelation analysis and is attributed to local heterogeneous strain variations on a length scale of at least 1–5 unit cells. The autocorrelation results are consistent with contributions to the line broadening as being due to order parameters for both the C1 → I1 and I1 → P1 transitions, which couple biquadratically, λQod2Qdispl2. Close correlation with enthalpy variations from previously published calorimetric data indicates that the driving force for ordering can be understood in terms of elimination of strain fields arising from accommodating more or less rigid AlO4 and SiO4 tetrahedra in the feldspar framework. The metastable incommensurate structure of anorthite is closely analogous to the stable incommensurate structure that develops at intermediate compositions in the plagioclase solid solution, confirming that the same strain relaxation mechanism dominates the properties and behavior of all structural states across the solid solution. Elimination of strain heterogeneity by ordering on the basis of I1 symmetry determines the form of non-ideal mixing shown by the solid solution at high temperatures, and changes in elastic properties may contribute to a break in the slope of partitioning of trace elements between crystals and melt.

Impact of electrolyte solutions on carbon dioxide fixation in single chamber Al–CO2 battery

Governments and research & development (R&D) organizations are actively initiating various programs and research strategies for CO2 capture, its utilization, and integration with long duration energy storage from renewable sources worldwide. In line with the carbon capture goals, here we report a novel electrochemical Al-CO2 battery cell, that can simultaneously capture CO2 and convert it into value-added products, in addition to long-duration energy generation and storage. This innovative approach employs cost-effective Al metal as an anode and an in-house synthesized Ni–Fe based bimetallic double hydroxide catalyst as the cathode, with meticulously optimized compositions and morphologies. We explore the impact of different aqueous electrolyte solutions compositions on the cell performance, demonstrating up to 10 h of stable long duration energy storage with a stable voltage profile. The cell exhibits low polarization even at high current densities of up to 12 mA cm−2 and maintains stable cycling over 500 h. Through Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray Diffraction and X-ray photoelectron spectroscopy (XPS) analysis, we determined that the discharge product is either NaAlCO3(OH)2 or KAlCO3(OH)2, distinct from the Al2(CO3)3 typically reported in conventional Al–CO2 batteries.

A novel and facile ultraviolet-induced photo-reduction for preparing oxidase-like AuNCs@H2N-ZIF-8 composites in alcohol-water solutions

The composites of H2N-ZIF-8 supported gold nanoclusters (AuNCs@H2N-ZIF-8) were prepared by UV-induced photochemical reduction method in the methanol–water solution. The photochemical reaction was attributed to the generation of free radical as.CH2·–OH, which reduced Au(III) to Au(0) and produced monodisperse AuNCs (<2.5 nm) in the mesoporous of H2N-ZIF-8. The generated AuNCs@H2N-ZIF-8 show oxidase-like properties to catalyze the oxidation of TMB, ABTS and OPD under mild conditions. Besides, the mechanism study by EPR shows that the composites can promote oxygen to generate singlet oxygen (1O2) and superoxide radicals (·O2-), endowing it excellent catalytic activity of oxidation. Further studies revealed that the large number of exposed small AuNCs in the mesoporous pores of H2N-ZIF-8 and the highly active 211 crystalline facets formed at the edges contribute to the ROS generation intrinsically. Therefore, the present study demonstrates the significance of photochemical reduction method to prepare highly efficient oxidase-like materials, opening up a new avenue to construct noble metal materials as ultra-small nanozyme.

Avseed Battery: Environmentally Friendly Battery Innovation as Electrolytes in Dry Batteries

Energy is a fundamental force driving transformative processes across various domains. It is perpetual and adheres to the law of energy conservation, remaining indestructible. However, the challenge lies in the finite nature of conventional energy sources, which convert energy for intended purposes and cater to diverse needs, often escalating the overall cost. Among the commonly employed energy sources, batteries play a pivotal role. This study explores the viability of avocado seeds as potential electrolytes in dry batteries. The objectives are to assess the effectiveness of avocado seeds as electrolytes and to investigate the impact of solution concentration and composition on the generated electrical energy. A dry element battery, known for converting chemical energy into electrical energy through Redox (Reduction-Oxidation) electrochemical reactions, serves as the experimental focus. Using a quantitative approach with laboratory experiments, five treatments were administered, featuring different ratios (1:1, 1:2, 1:3), a negative control with avocado seeds, and a positive control with salt. The bio-battery effectiveness assessment revealed that the P4 composition (negative control with avocado seeds) exhibited the highest initial voltage of 3.4 V and an extended runtime of 156 hours. In summary, this research underscores the potential of avocado seeds as electrolytes in dry batteries, supported by observations of voltage levels and ignition times.

Computational decomposition and composition technique for approximate solution of nonstationary problems

Stable computational algorithms for the approximate solution of the Cauchy problem for nonstationary problems are based on implicit time approximations. Computational costs for boundary value problems for systems of coupled multidimensional equations can be reduced by additive decomposition of the problem operator(s) and composition of the approximate solution using particular explicit–implicit time approximations. Such a technique is currently applied in conditions where the decomposition step is uncomplicated. A general approach is proposed to construct decomposition–composition algorithms for evolution equations in finite-dimensional Hilbert spaces. It is based on two main variants of the decomposition of the unit operator in the corresponding spaces at the decomposition stage and the application of additive operator-difference schemes at the composition stage. The general results are illustrated on the boundary value problem for a second-order parabolic equation by constructing standard splitting schemes on spatial variables and region-additive schemes (domain decomposition schemes).

Efficacy of denture cleansers on Candida albicans adhesion and their effects on the properties of conventional, milled CAD/CAM, and 3D-printed denture bases.

Evaluate the efficacy of denture cleaners on the adhesion of Candida albicans and their effects on the surface, optical, and mechanical properties of resins for conventional, milled, and 3D-printed denture bases. A total of 240 resin samples were made, 120 for testing Candida albicans adhesion, optical stabilities (ΔE00), roughness (Ra), hydrophilicity (°), surface free energy (Owens-Wendt) and 120 samples for testing Candida albicans adhesion, surface microhardness (Knoop), flexural strength and modulus of elasticity in a three-point test, in which they were divided into 3 groups of denture resin (n = 40) and subdivided into 5 cleaners of dentures (n = 8). Data were evaluated by two-way ANOVA and Tukey's test for multiple comparisons (α = 0.05). Denture cleaners with an alkaline solution and dilute acid composition were those that showed the greatest effectiveness in reducing Candida albicans (P < 0.001), however 1% NaOCl significantly affected the properties of the resins (P < 0.05). Denture 3D-printed showed that the surface microhardness was significantly lower for all cleansers (P < 0.05). Listerine demonstrated superior efficacy in reducing Candida albicans with minimal effect on denture properties, whereas 1% NaOCl had a significant negative impact on the properties. The mechanical properties were significantly lower in 3D-printed resin than in other resins for all denture cleansers. Denture base materials are being sold to adapt to the CAD/CAM system, increasing the number of users of dentures manufactured with this system. Despite this, there is little investigation into denture cleaners regarding the adhesion capacity of microorganisms and the optical, surface and mechanical properties of dentures, thus requiring further investigation.

Auto-combustion synthesis and characterization of La2CrMnO6/g-C3N4 nanocomposites in the presence trimesic acid as organic fuel with enhanced photocatalytic activity towards removal of toxic contaminates

Constructing semiconductor materials based on layered graphitic carbon nitride (g-C3N4) and metal oxides can help in extending the lifetime of charge carriers and aid in resolving the low number of active sites on their surface for light-driven processes. Herein, we initially designed La2CrMnO6 nanostructures through trimesic acid-assisted auto-combustion route and subsequently, La2CrMnO6/g-C3N4 nanocomposites were prepared by ultrasonic-assisted co-precipitation method with improved UV-catalytic performance. The shape, size distribution and various properties of nano-sized products were measured via diverse description systems of microscopic and spectroscopic. The photocatalytic performances of the La2CrMnO6 nanoparticles and La2CrMnO6/g-C3N4 nanocomposites were compared by degradation of artificial dyes under the UV-light region. Besides, the impacts of dye type, diverse weight percentages of g-C3N4:La2CrMnO6 in composite, scavenger kind and dye solution concentration were studied on modifying ability of nano-catalyst utility. The outcomes manifested La2CrMnO6/g-C3N4 (80:20) nanocomposites have the greatest efficiency, where the highest MO decomposition of 80.98 % was achieved at 10 ppm within 90 min of irradiation. Moreover, the feasible mechanism of MO elimination by UV catalytic purpose was considered.

Mechanism and experimental investigation on the formation of micro‐triangle stepped jet in composite spinning solution

AbstractIn the field of nanotechnology, rotary jet spinning technology has garnered attention due to its unique advantages in fabricating composite nanofibers. The composite nanofibers prepared using this technology exhibit exceptional purity, uniformity, and consistency, thereby enhancing reliability and controllability in practical applications. During the process of rotary jet spinning, the spinning solution flows into the nozzle and converges at a micro‐triangle under the combined influence of centrifugal force, viscous force, surface tension, and gravity. Stepped jet refers to the flow phenomenon occurring within a channel with a gradually decreasing cross‐sectional area. In this process, an increase in the flow velocity of the composite spinning solution aids in stabilizing stretching at the micro‐triangle which is crucial for forming continuous jets. This article analyzes cone formation mechanisms for composite spinning solutions and stepped jet principles while establishing corresponding models that reflect relationships between solution velocity magnitude and parameters such as rotational speed, concentration, and nozzle diameter. Finally, polyethylene oxide (PEO)/polyvinylpyrrolidone (PVP) composite nanofibers were prepared using a rotary jet spinning device where experimental investigation focused on examining how parameters such as rotational speed, solution concentration, and nozzle diameter impact motion of spinning solution within micro‐triangle.Highlights Preparation of PEO/PVP composite nanofibers by rotary jet spinning. Presentation of cone formation mechanisms for composite solutions. The stepped injection principle was proposed. Modeling of composite solution motion. Rotational speed, solution concentration, and nozzle diameter impact motion.

Development Of A Distance Education Experiment Set That Allows The Ratio Of Chemical Components In Hydroponic Farming Nutrient Liquid To Be Estimated By Artificial Intelligence

With the increase and development of electronic systems, especially with the advancement of artificial intelligence (AI) applications, AI has begun to meet many of humanity's needs. Due to the rapidly increasing human population and the decreasing availability of fertile land, the use of AI has become necessary in rapidly expanding soilless agriculture practices. One of the biggest challenges in soilless agriculture is the inability to accurately determine the chemical content of nutrient solutions in real-time. In this study, the results of inductively coupled plasma optical emission spectrometry (ICP-OES) and electrical conductivity (EC) were obtained for 300 hydroponic agriculture nutrient solutions containing different ratios of Mg, K, and P minerals. The obtained data were evaluated using artificial neural networks in Matlab® software, with ICP-OES results as inputs and EC results as outputs (3 inputs-1 output). The results were uploaded to the cloud system using Firebase, and an EC meter capable of communicating with the cloud was developed. The results of the produced EC meter were compared with the data in the cloud, and attempts were made to determine the element ratios in the nutrient solution content of 300 samples using artificial neural networks. The Pearson Correlation Constant (R) was found to be 0.860 for all data. According to the test results obtained with the produced system, the success rate of the artificial neural network in detecting the chemical composition of the nutrient solution ranged from 53.2% to 87.4% depending on the chemical ratios in the nutrient solution.

Powstawanie polifazowej asamblaży minerałów z grupy platynowców w masywie dunitowo-szonkinitowym Inagli w Aldan Shield na platformie syberyjskiej

The Inagli massif is a concentric-zonal ring massif consisting of a dunite core bordered by a sequential series of peridotites, pyroxenites and shonkinites. In dunites, there are densely disseminated accumulations of chromspinelides, as well as schlieren and veined particles of massive chromitites, to which polyphase growths of platinum-group minerals (PGM) are confined. The Inagli intrusive, like the well-known Konder massif, belongs to an independent "Aldan" type of platinum-bearing deposits. The Aldan type of ring intrusions is a platform analogue of the "Ural-Alaskan" zonal dunite-gabbro massifs of orogenic regions. In placers, dunites and chromitites of the Inagli massif, PGM are mainly represented by isoferroplatinum (Pt3Fe) with an admixture of iridium up to 8 wt %. In isoferroplatinum, symplektitic iridium particles and small inclusions of osmium, laurite, ehrlichmanite, malanite, as well as other sulfides and arsenides of platinum-group elements (PGE) are often observed. The bulk composition of such polymineral aggregates can be calculated based on the volume ratios and chemical composition of individual phases. The results obtained in this way show that the compositions of the initial polycomponent solid solutions vary from Pt-Ir-Fe to Ir-Os-Ru-Rh-Pt-Pd-Fe alloys. Polycomponent homogeneous solid solutions, which composition gradually changes from Ru-Rh-Ir-Os minerals to Fe-Pt alloys, are known in the Witwatersrand placers. A similar series of solid solutions of PGE is identified in the placers of the Guli massif on the Siberian platform. Unlike the placers of the Witwatersrand and Guli massif, where PGM are mainly represented by Os-Ir alloys, Inagli minerals have mainly a Pt-Ir-Fe composition with a low proportion of Os. The structures of most natural polyphase PGM aggregates are similar to those of artificial alloys, therefore, the former are also products of crystallization of multicomponent metal melts and their subsequent solid-phase transformations. The limits of solubility between PGE differ significantly, therefore, depending on the initial composition of metal alloys, both polycomponent solid solutions and polymineral aggregates can be formed. Based on the analysis of combined double and triple diagrams of PGE systems, the author considers possible ways of evolution of phase transformations of alloys of different composition.

Chrononutrition in Critical Illness.

Circadian rhythms in humans are biological rhythms that regulate various physiological processes within a 24-hour time frame. Critical illness can disrupt the circadian rhythm, as can environmental and clinical factors, including altered light exposure, organ replacement therapies, disrupted sleep-wake cycles, noise, continuous enteral feeding, immobility, and therapeutic interventions. Nonpharmacological interventions, controlling the ICU environment, and pharmacological treatments are among the treatment strategies for circadian disruption. Nutrition establishes biological rhythms in metabolically active peripheral tissues and organs through appropriate synchronization with endocrine signals. Therefore, adhering to a feeding schedule based on the biological clock, a concept known as "chrononutrition," appears to be vitally important for regulating peripheral clocks. Chrononutritional approaches, such as intermittent enteral feeding that includes overnight fasting and consideration of macronutrient composition in enteral solutions, could potentially restore circadian health by resetting peripheral clocks. However, due to the lack of evidence, further studies on the effect of chrononutrition on clinical outcomes in critical illness are needed. The purpose of this review was to discuss the role of chrononutrition in regulating biological rhythms in critical illness, and its impact on clinical outcomes.

Tribological Properties of Composites Based on Single-Component Powdered Epoxy Matrix Filled with Graphite.

Composites based on powdered single-component epoxy matrix are an alternative technological solution for composites produced using liquid epoxy resins. This article describes in detail the process of producing graphite-reinforced composites for tribological applications. The advantages and disadvantages of technological processes where the matrix is a single-component epoxy powder were demonstrated, and the properties of the obtained materials were examined. A series of composite materials with the graphite filler with sizes below 10 μm and below 45 μm and weight additions of 5, 10, 20, 30% were produced. Mechanical tests and tribological tests conducted with the pin-on-block method were performed, and the mechanism of tribological wear was described. The conducted research allowed us to conclude that the incorporation of graphite, regardless of particle size, above 10% by weight results in a significant reduction in the friction coefficient (approximately 40-50% lower than in unfilled epoxy resin), which is beneficial in the production of cheap self-lubricating materials.

Evaluation and selection of sustainable hydrogen production technologies with unknown expert weights based on extended MARCOS under hybrid information

The selection of sustainable hydrogen production technologies (HPT) is a paradigm transformation for industrial enterprises to pursue commercial benefits and environmental performance, which has increasingly attracted the attention in academic circles. Therefore, the chief orientation of this research is to construct a novel sustainability-oriented decision-support framework for hydrogen production system. Firstly, an approach is developed to determine expert weights under each criteria in a linguistic environment. Secondly, the Measurement of Alternatives and Ranking according to Composite Solution (MARCOS) method is extended to prioritize sustainable HPT under hybrid information (HMARCOS). Finally, a case study of 5 typical HPT regarding 15 sustainability indicators is conducted. The results display the biomass gasification has the highest sustainability priority for hydrogen production compared with wind turbine electrolysis, photovoltaic electrolysis, steam methane reforming and coal gasification. Furthermore, the reliability and availability of the integrated framework is demonstrated by the comparisons with other approaches.