Initial Mixture Research Articles

Experimental Investigation of Ammonia/Oxygen/Argon Combustion: The Role of Equivalence Ratio and Nozzle Shape in a Constant Volume Combustion Chamber with Sub-chamber

The global rise in carbon emissions presents a rising challenge for current and future generations. In the pursuit of zero carbon emissions, ammonia (NH3) has emerged as an attractive alternative energy source. Ammonia offers a carbon-free fuel option with a higher energy density than liquid hydrogen while maintaining ease of transport and storage. However, ammonia still has its drawbacks, such as a high autoignition temperature, slow burning velocity, and low heating value, that demand further investigation of its combustion characteristics. This experiment was done to study the effect of nozzle shape and equivalence ratio (ɸ) on the combustion of an ammonia/oxygen/argon mixture using a constant volume combustor equipped with a sub-chamber. The fuels were premixed for 10 minutes and conditioned to an initial pressure of 0.2 MPa and an initial mixture temperature of 423 K. The results show that the different nozzle shapes each have their advantages in terms of pressure and jet speed. Overall, the lean mixtures (ɸ0.6 and ɸ0.8) consistently performed better compared to the stoichiometric mixtures (ɸ1.0) in all categories investigated in this study. The round nozzle generates higher pressure, while the special shape nozzle enhances jet speed, highlighting trade-offs between the two.

Change in the Chemical State of Phosphorus Sulfide Molecules Inside Single‐Walled Carbon Nanotubes

This article presents the first experiments on filling single‐walled carbon nanotubes (SWCNTs) with the phosphorus sulfides P4S3 and P4S10 using the ampoule method. Transmission electron microscopy examination reveals the encapsulation of phosphorus and sulfur species inside the cavities of SWCNTs without the formation of any regular structures. X‐ray photoelectron spectroscopy observes different oxidation states of P and S atoms, depending on the P/S ratio in the initial mixture used to fill the nanotubes. The Raman signals associated with the encapsulated species are low in intensity, and the vibrational modes are shifted and broadened as compared to those in crystalline P4S3 and P4S10. The proposed models for the arrangement of sulfur and phosphorus inside SWCNTs suggest the formation of 1D amorphous glassy phosphorus sulfides with stoichiometric ratios close to those of elemental phosphorus and sulfur in the initial mixtures.

Numerical simulation of flame propagation characteristics of NH3/Air flames assisted by non-equilibrium plasma discharge

Nanosecond non-equilibrium plasma-assisted combustion technology emerges as a reliable novel approach to enhance the flame propagation speed of NH3. In this study, we developed a zero-dimensional + one-dimensional (0-D+1-D) non-equilibrium plasma-assisted combustion model to investigate the impact of nanosecond pulse discharge on the freely propagating flame speed of NH3/Air mixture. The results reveal that due to the plasma discharge, abundant intermediate species (N2H4, N2H3, NO, H2O2) are formed at the inlet and are subsequently transported downstream, facilitating flame propagation. As a result, the speed of the 1-D freely propagating flame increases, and the flame front is closer to the inlet compared to the non-plasma condition. The transport effect of H2 is also evident, with high concentrations of H2 from the inlet providing the basis for reactions at the flame front that promote combustion. Furthermore, after the initial mixture flows into the flame front, a slight increase in heat release is observed, but this increase occurs within a very limited distance. Notably, in the case of plasma, a stronger heat release is evident at the flame front. Moreover, with plasma, the peaks of OH, H, O, NH2, and HO2 are higher and earlier than those of the non-plasma case due to the transport and kinetic effects of plasma. Pathway flux analyses reflect significant changes in the production and consumption paths of the three components OH, H, and O, which are most important for consuming NH3 due to plasma addition. The higher OH mass fraction promotes the chain reactions that consume NH3, effectively enhancing the flame propagation speed. Novelty and significance statementThis study introduces a novel 0-D+1-D nanosecond non-equilibrium plasma-assisted combustion model to examine the impact of nanosecond pulse discharge on NH3/Air flame propagation. It uniquely analyzes the interaction between species at the inlet and flame front, highlighting the transport effects of plasma-generated intermediates (N2H4, N2H3, NO, H2O2, H2) that enhance flame speed, with a detailed pathway analysis of key species (O, OH, H).

Parallel (competitive) reactions of micelle formation and cyclodextrin–surfactant inclusion complex formation in aqueous solution: A consequence of the Gibbs–Duhem equation—invariance of the mass action law and the possibility of determining the equilibrium constant of the inclusion complex

The Gibbs–Duhem equation results in the independence between the standard Gibbs free energy of micelle formation and the standard Gibbs free energy of monocomponent surfactant’s and cyclodextrin’s (CD’s) inclusion complex formation in aqueous solution. The experimental data show that the surfactant’s critical micellar concentration increases in the presence of CD. At a constant temperature, the standard Gibbs free energy of micelle formation remains constant, irrespective of the presence of parallel competitive processes such as inclusion complex formation. This indicates that the critical micellar concentration remains unchanged at the corresponding concentration scale. As a result, the equilibrium constant for surfactant–CD inclusion complex formation can be determined by changing the critical micellar concentration in the presence and absence of CD. A graphical method for determining the equilibrium constant of the inclusion complex is also presented. An analytical approach for analyzing the influence of the formation of the inclusion complex with CD on the formation of the binary mixed micellar pseudophase is presented. Suppose that different values exist for the equilibrium constants of the formation of the inclusion complex for two surfactants from their binary mixture. In this case, there is a change in the initial mole fraction from the initial mixture of surfactants, which should be considered when applying the regular solution theory protocol when determining the parameters of a binary mixed micelle in the presence of CD.

Molecular Insights into Gas-Particle Partitioning and Viscosity of Atmospheric Brown Carbon.

Biomass burning organic aerosol (BBOA), containing brown carbon chromophores, plays a critical role in atmospheric chemistry and climate forcing. However, the effects of evaporation on BBOA volatility and viscosity under different environmental conditions remain poorly understood. This study focuses on the molecular characterization of laboratory-generated BBOA proxies from wood pyrolysis emissions. The initial mixture, "pyrolysis oil (PO1)", was progressively evaporated to produce more concentrated mixtures (PO1.33, PO2, and PO3) with volume reduction factors of 1.33, 2, and 3, respectively. Chemical speciation and volatility were investigated using temperature-programmed desorption combined with direct analysis in real-time ionization and high-resolution mass spectrometry (TPD-DART-HRMS). This novel approach quantified saturation vapor pressures and enthalpies of individual species, enabling the construction of volatility basis set distributions and the quantification of gas-particle partitioning. Viscosity estimates, validated by poke-flow experiments, showed a significant increase with evaporation, slowing particle-phase diffusion and extending equilibration times. These findings suggest that highly viscous tar ball particles in aged biomass burning emissions form as semivolatile components evaporate. The study highlights the importance of evaporation processes in shaping BBOA properties, underscoring the need to incorporate these factors into atmospheric models for better predictions of BBOA aging and its environmental impact.

Экспериментальные исследования формирования и горения водородно-воздушных смесей при проливах жидкого водорода и при воздействии на горение смесей водяных завес в частично ограниченном пространстве

Experimental studies of processes of liquid hydrogen spill and evaporation and the generation of explosive and fire-hazardous hydrogen-air mixtures in a partially confined space with varying degrees of confinement (varying degrees of leakage of openings) on a stand of 96 m3 volume have been conducted, which involved the ignition of mixtures with delayed and non-delayed inflammation and the measurement of overpressure of explosion; the impact of water screen on these processes have been studied as well. The experiments with duty torches feature rapid combustion of the mixture when the boundary of the generating explosive cloud approaches the area of installed burners, and the volume of the faintly glowing flame of the burning-out mixture rises to a significant height. For all the experiments, the overpressure in the shock wave generated by the flame was approximately the same, equal to 0.8–1.2 kPa. For experiments with delayed ignition, the generation and development of a visible hydrogen-air mixture cloud and its rapid combustion at the activation of burner flares were registered; the visible flame velocities reached 3,050 m/s. At the same time, the delayed ignition within the range of 1–3.2 s did not cause a significant increase of overpressure in the shock wave. Therefore, the specifics of the mixture combustion process in case of liquid hydrogen spills in a confined space are mainly determined by the conditions of mixture generation that significantly differ from the conditions of the generation of hydrogen-air mixture in free space. When hydrogen-air mixtures are exposed to a water screen after the ignition in a confined space, as well as in the air atmosphere, the processes of mixture combustion are activated due to initial combustible mixture flame turbulence. The turbulence of the initial combustible mixture flame is conducted on droplets acting as a periodic volumetric obstacle on the route of the flame front intensifying the flame. At the same time, water screens, with preemptive action, reduce the pressure in the shock wave by the time of the hydrogen spill.

Copolymers of Vinylphosphonic and p‐Methacrylamidobenzoic Acids and their Complexes with Lanthanide Ions

AbstractNew copolymers of vinylphosphonic and p‐methacrylamidobenzoic acids of varying compositions were synthesized via free radical copolymerization. The structure of the obtained polymers was confirmed by NMR and FTIR spectroscopy. As the proportion of vinylphosphonic acid in the initial reaction mixture increased, the yield of the copolymer and its molecular mass both decreased. The synthesized copolymers were found to form stable soluble luminescent complexes in dilute aqueous solutions, with a concentration range of 0.002 to 0.02 mg/ml. An increase in the concentration of vinylphosphonic acid moieties in copolymers was accompanied by a noticeable decrease in the luminescence intensity. The new copolymers’ ability to bind efficiently with lanthanide ions renders them a promising material for the design of polymeric contrast agents, preparations for radioimmunotherapy and photodynamic therapy.

Synthesis and Characterization of Shungite Modified Poly-N-Ninylpyrrolidone-Agarose Composites for Medical Application.

A systematic investigation was conducted to synthesize hybrid composite materials that use synthetic poly-N-vinylpyrrolidone and natural (agar-agar) macromolecules with plasticizers (PEG-400) and mineral filler shungite by means of electron irradiation. The XRD and SEM data showed that the structure of the resulting hybrid composites is an interpenetrating network with distributed particles of mineral component. It has been established that the mechanical properties of hybrid composites are determined mainly by the structural organization of the interpenetrating polymer network formed under electron irradiation of the initial synthetic and natural polymer mixture in the presence of plasticizers, as well as by the conditions for intercalation of polymer segments into the mineral matrix and vice versa. It has been revealed that the degree of swelling of hybrid composites strongly depends on the concentration of a low-molecular plasticizer in the polymeric interpenetrating network, which easily impregnates into the matrix of shungite. Successfully obtained [PVP-AA-PEG] hydrogels with shungite can be applied in regenerative medicine as wound healing dressings.

Self-propagating high-temperature synthesis of AlN–TiC powder composition using sodium azide and C2F4 fluoroplastic

Producing powder compositions using conventional processing technology can lead to the formation of large agglomerates and, therefore, makes it difficult to obtain a uniform microstructure. The production of composites by self-propagating high-temperature synthesis can reduce costs and the number of technological stages, as well as lead to obtaining composites that are more homogeneous. Synthesis by the combustion of mixtures of powder reagents of sodium azide (NaN3), fluoroplastic (C2F4), aluminum and titanium with different ratios of reagents in a nitrogen gas atmosphere at a pressure of 4MPa was used for the production of a highly dispersed powder ceramic AlN–TiC composition. Thermodynamic calculations have confirmed the possibility of synthesis of AlN–TiC compositions of different formulations in combustion mode. The dependences of temperature and combustion rate on the composition of the initial mixtures of reagents were experimentally determined for all stoichiometric reaction equations. The study have shown that the experimentally found dependences of combustion parameters on the ratio of the initial components correspond to the theoretical results of thermodynamic calculations. The formulation of the synthesized composition differs from the theoretical composition by a lower content of target phases and the formation of Al2O3, Na3AlF6 and TiO2 side phases. The powder composition consists of aluminum nitride fibers with a diameter of 100–250nm and ultradisperse particles of predominantly equiaxed and lamellar shapes with a particle size of 200–600nm. As the combustion temperature increases to produce the largest amount of titanium carbide phase, the particle size increases to the micron level.

The Effect of Nickel Content and Mechanical Activation on Combustion in the 5Ti + 3Si + <i>х</i>Ni System

Intermetallic alloys were synthesized in the 5Ti + 3Si + xNi system by the method of self-propagating high-temperature synthesis (SHS) and mechanosynthesis. The influence of nickel content on the morphology, size and yield of composite particles after mechanical activation (MA) of mixtures was studied. The dependences of the maximum temperatures and combustion rates, phase composition, morphology and elongation of synthesis products on the nickel content for the initial and MA mixtures are studied. Under the conditions of the experiments conducted in this work, combustion process was able to realize and at the same time the samples burned completely at a nickel content of 10 to 60 wt.% in the 5Ti + 3Si + xNi system. After MA, the samples from the 5Ti + 3Si mixture burned to the end, and during the activation of the 5Ti + 3Si + 40% Ni mixture, mechanochemical synthesis occurred. With increasing nickel content combustion temperature decreases, and combustion velocity behaves nonmonotonically, increases the size of composite particles and decreases the yield of the mixture after MA. MA practically did not affect the maximum combustion temperatures of mixtures of 5Ti + 3Si + xNi. A multiple (from 0.7 to 2.9 cm/s) increase in the burning rate of samples from MA mixtures with an increase in the Ni content from 20 to 30 wt. % was recorded. An increase in the nickel content leads to an increase in the content of triple phases and the amount of melt in the synthesis products of mixtures of 5Ti + 3Si + xNi. Shrinkage of product samples increases with increasing nickel content in the initial mixtures. After MA, the shrinkage of the product samples is replaced by their growth. Explanations of the observed dependencies are proposed.

Determination of Reactivity Ratios of N-butyl Acrylate/methyl Methacrylate Copolymerization by NMR Spectroscopy

In this study, the reactivity ratios of n-butyl acrylate (BA) and methyl methacrylate (MMA) were investigated. The copolymerization reactions were performed in toluene at 70 oC, using azobisisobutyronitrile as the initiator. The composition of the initial monomer mixture and copolymers was easily determined with the help of proton nuclear magnetic resonance (1H-NMR) spectroscopy. The molar fractions of BA and MMA in the feed were varied to apply the linear methods of Fineman–Ross and Kelen - Tudos. The calculation gave the reactivity ratios and . The computed copolymer composition was relatively close to the real copolymers obtained, with a 5% deviation.

Effect of lactic acid bacteria inoculation on the aflatoxin B1 contamination and the diversity of yeast communities in Aspergillus flavus-contaminated experimental corn silage

AbstractThe present work aimed to study the yeast communities of whole crop corn silages (CS) that were previously contaminated with aflatoxin-producing Aspergillus flavus (CSCA). In addition, the effect of lactic acid bacterium (LAB) inoculation on the aflatoxin B1 (AFB1) content, genotoxicity, yeast load, and diversity of yeast communities were also investigated. In A. flavus contaminated silages, after two months, the AFB1 content was 40% lower with LAB inoculation, also a lower level of genotoxicity was determined. The number of yeasts cultured from the initial mixture of chopped whole crop corn was 4.8 × 107 CFU g−1 wet mass, while only 2.4 × 106 CFU g−1 from the CSCA and 7.1 × 105 CFU g−1 from the LAB-inoculated CSCA could be cultured. Based on 144 randomly isolated strains, the yeast community of the initial mixture consisted of 8 species. In contrast, the yeast community of CSCA consisted only of 4 species determined by 132 randomly selected isolates. LAB-inoculated CSCA consisted also of 4 species based on 158 randomly isolated strains. Saccharomyces cerevisiae and Pichia kudriavzevii proved to be predominant in the CSCA, while S. cerevisiae and Meyerozyma guilliermondii were the most abundant in the LAB-inoculated CSCA. The species richness was also confirmed by alpha diversity values (1.827, 1.188, and 1.123 as Shannon's indices for CS, CSCA, and LAB-inoculated CSCA, respectively). In response to LAB inoculation, the species diversity decreased considerably.

A comparative study on the combustion of lean NH3/H2/air ignited by pre-chamber turbulent jet ignition modes

Internal combustion engines fueled with mixtures of hydrogen (H2) and ammonia (NH3) are potential power devices for reducing carbon emissions. To improve the ignition and combustion performance of NH3/H2, turbulent jet ignition (TJI) can be used. This study aims to investigate NH3/H2/air combustion under TJI modes at low equivalence ratios. Considering that the adoption of the scavenging system is beneficial for improving the reactivity of the pre-chamber, the effect of active TJI with scavenging is also explored. The results show that injecting 1.2 times the initial mixture volume of air is optimal for scavenging, and the scavenging effect becomes significant as the NH3 fraction increases. Using conventional active TJI and active TJI with scavenging effectively improves ignition performance and flame propagation, reducing sensitivity to the equivalence ratio compared to passive TJI mode. Although the adoption of active TJI modes improves the lean flammability limit of NH3/H2, weak flame propagation may occur in the early stage of combustion under ultra-lean conditions. Appropriately increasing the injection of auxiliary H2 can effectively improve this phenomenon.

Optimal formulation and performance evaluation of functional ultra-high performance concrete with barium ferrite

The employment of a core catcher is instrumental in enhancing the safety of nuclear power facilities in the event of severe accidents, with sacrificial materials serving as fundamental constituents. Currently, cement-based sacrificial materials are prevalently utilized due to their straightforward construction methodologies and economical production costs. These materials are designed to withstand significant impact loads arising from the descent of core melt during severe accidents. To augment the impact resilience of sacrificial materials, a novel functional ultra-high performance concrete (FUHPC) incorporating barium ferrite has been developed. Using the Modified Andreasen and Andersen particle packing model to determine the initial mixture of FUHPC, and the impact of barium ferrite on the mechanical and thermal properties of FUHPC was systematically evaluated. Furthermore, the influence of barium ferrite on the FUHPC's microstructure was examined with mercury intrusion porosity and scanning electron microscopy techniques. The findings indicate: (1) Optimal barium ferrite incorporation led to a decrease in the porosity and the threshold pore diameter of FUHPC; (2) The flexural and compressive strengths, as well as the elastic modulus of FUHPC, were found to increase within the ranges of 4.41%–17.50 %, 2.88%–22.91 %, and 5.80%–15.06 %, respectively, as a result of suitable barium ferrite additions; (3) At a barium ferrite concentration of 2 vol%, the chloride migration coefficient of FUHPC was reduced by 21.43 %; (4) The presence of barium ferrite enhanced the impact performance of FUHPC, with a 21.38 % increase in impact resistance noted at a barium ferrite content of 2 vol%; (5) In high-temperature scenarios, the formation of channels from melted polypropylene fibers served to mitigate the spalling of FUHPC; (6) Upon considering the effects of barium ferrite on both room temperature and elevated temperature performance, as well as on microstructural characteristics, the optimal barium ferrite content was determined to be 2 vol%.

Correlations between sewage sludge composting physicochemical parameters and emissions of greenhouse gases and ammonia: A statistical analysis

Mitigating the environmental impact of composting by the reduction of greenhouse gases (N2O, CH4) and ammonia (NH3) emissions is a major challenge. To meet this challenge, the understanding of the relationships between composted substrates initial physicochemical parameters and gas emissions is essential. From a long-term perspective, it will allow to guide the recipe formulation of the initial mixture to be composted, with a view to reducing gas emissions during composting. This study gathered literature data targeting sewage sludge composting and performed statistical correlation analyses between cumulative gas emissions and the following parameters: sewage sludge, bulking agent and composted mixture initial physicochemical parameters (pH, dry matter, total carbon, total nitrogen, C/N), the dry mass ratio of sewage sludge to bulking agent and the duration of composting. The average values of cumulative emissions show a large variability: 1.37 ± 2.71 gC.kg initial mix DM−1, 0.13 ± 0.17 gN.kg initial mix DM−1 and 2.23 ± 2.79 gN.kg initial mix DM−1 for CH4, N2O and NH3 emissions respectively. Although the correlation analysis highlighted some significant interesting correlations between initial physicochemical parameters and gas emissions (p.value < 0.05), reliable multiparametric model could not fit the data, meaning that the actual literature data are not sufficient to explain most part of gas emissions. Among the most interesting relationships, the study showed that the dry matter of the composted mixture is negatively correlated to N2O emissions, while the ratio of sewage sludge to bulking agent and the duration of composting are positively correlated to N2O emissions. It was also shown that the pH of the bulking agent is positively correlated to NH3 emissions. Considering the large part of the emission variability that is not explained and the difficulty to link the correlation with their causality, it will be interesting to improve composting gas emissions knowledge in future research by analyzing free air space, bulking agent adsorption capacity and available and biodegradable organic matter. These parameters are of particular interest in solving the main problems associated with sewage sludge composting, namely porosity and nitrogen retention. This study also highlighted the necessity to extend the duration of the composting studies over 40 days in order to measure possible N2O late release and better identify parameters influencing N2O emissions.

Characterization of ZnWO4, MgWO4, and CaWO4 Ceramics Synthesized in the Field of a Powerful Radiation Flux

This paper presents the results of a study on the morphology, structure, and luminescent properties of ceramics synthesized in the radiation field of MeWO4 compositions (where Me is Mg, Ca, and Zn). The synthesis of ceramics was carried out by the direct action of the electron flux on an initial mixture of powders of the given stoichiometric composition. WO3, ZnO, MgO, and CaO powders with particle sizes in the range of 1–50 microns were used for the synthesis of the samples. It was found that the yield of the radiation synthesis reaction (the ratio of the mass of the sample and the charge used), when treated with an electron flux with an energy of 1.4 MeV and a flux power density of 15–18 kW/cm2, was in the range of 75–99%. The synthesis of all compositions was carried out under the same radiation treatment modes, although the melting temperatures of the starting materials varied significantly and ranged from 1473 °C (WO3) to 2825 °C (MgO). The study of the ceramic structure showed that under the radiation effect of powerful radiation fluxes on the charge, a crystalline phase of the appropriate composition formed, regardless of the synthesis modes. The results of XRD studies show that during the radiation treatment of the charge, ceramics are formed mainly with the crystalline phases ZnWO4, MgWO4, and CaWO4. These resulting MeWO4 ceramics can be used for the same purposes as crystals. Photoluminescence (PL) and cathodoluminescence (CL) were studied under excitation using stationary ultraviolet radiation and nanosecond pulses of electron flux. In general, the PL and CL of synthesized ceramic samples ZnWO4, MgWO4, and CaWO4 showed that their luminescent properties are similar to those of luminescence in corresponding crystalline materials. This indicates the formation of a crystalline phase in synthesized ceramic samples.

Approach to the circular economy through agro-livestock waste composting with heat recovery and agricultural use of the resulting compost

In this work, plant waste and cow manure were co-composted to recover the heat generated during the thermophilic stage of composting by heating water through conducting heat exchangers buried in the pile. The parameters associated with the degradation and humification of organic matter during composting and the agronomic and economic value of the final compost were also determined. Furthermore, the effects of adding the obtained compost on soil agronomic characteristics and alfalfa yield and production profitability were compared with those of mineral fertilisation, cow manure and a control without amendment. The total energy recovered from composting was 14,528W or 0.105 MJ kg−1 dry matter of the initial waste mixture. Extracting heat from composting did not negatively affect the quality of the compost since this material had an adequate level of organic matter stability and maturity, notable nutrient content, low concentrations of potentially toxic elements and an absence of phytotoxicity. Moreover, applying compost to the soil increased its organic matter and nutrient content, contributing to greater alfalfa production. Increased alfalfa production led to a higher net income from using compost as an organic fertiliser (16,488 USD ha−1). Therefore, composting agricultural and livestock wastes is a viable method for managing these wastes, obtaining sustainable thermal energy and producing compost with adequate agricultural quality. This contributes to closing agricultural and livestock production cycles with notable economic benefits within a circular economy framework.

Enhancing the performances of self-consolidating composite mortars with Alfa fibers and slag: A combined Taguchi-ANN optimization

Alfa fiber-reinforced self-compacting mortars (SCMs) offer enhanced workability. Thus, the potential of combining natural Alfa fibers and ground granulated blast furnace slag (GBFS) to optimize the rheological and mechanical properties was ascertained. The effect of fibers and GBFS on the properties of SCMs after treatment with linseed oil and NaOH was also evaluated. Partial substitution of cement by slag (10 % and 30 %.) was achieved. Mini cone spreading, V-funnel flow tests as well as compressive and bending tests at 7 days and 28 days were performed on the prepared mixtures. For optimization and predictive purposes, both Taguchi optimization and Artificial Neural Network modeling were employed. Our results indicated that, according to Taguchi experimental design, the use of 1 % fiber in the initial mixture achieved a good distribution within the paste and improved flexural strength. In addition, the treatment of fibers with NaOH actually improved the structure and bonding surface. Fiber content and GBFS replacements achieved the desired rheological and mechanical characteristics. Prediction of both compressive and flexural strengths was successfully achieved by an accurate application of machine a learning algorithm based on six inputs, one hidden layer and four outputs. The combined ANN-Taguchi approach provided accurate predictions of SCM performances and identified a robust mix-design that was less prone to fluctuations in the initial material properties. Alfa fibers and GBFS promoted both fresh and hardened properties. This study demonstrated the effectiveness ML and statistical optimization in developing high-performance, sustainable-SCMs with superior workability and strengths, making them ideal for various construction applications.

Thermodynamic and Experimental Substantiation of Comprehensive Processing of Zinc Sulfide Ore and Its Concentration Tailings to Extract Non-Ferrous Metals and Produce a Silicon Ferroalloy

This article presents the results of thermodynamic and experimental studies on the joint processing of a mixture of Shalkiya deposit zinc–lead sulfide ore and its concentration tailings in the presence of coke and magnetite. Using the HSC-6.0 software package, it was established by thermodynamic modeling that the silicon-containing products of the SiO2 reduction in the system under consideration are FeSi, Si, Fe3Si, Fe5Si3, FeSi2, FeSi2.33, and SiOg, which, based on the starting reduction temperature, form an increasing series: Fe3Si (1200 °C); Fe5Si3, Si (1400 °C); and SiOg, FeSi2, FeSi2.33 (1500 °C). The smelting of the zinc–lead sulfide ore and concentration tailings mixture in the case of replacing 55% of the iron contained in the magnetite concentrate with steel shavings iron allowed us to produce FeSi45 ferrosilicon (41.9%–42.1% Si), with the extraction of 85% of the silicon in it, and sublimates containing 26.03% zinc and 13.47% lead, with the extraction of 97% of the zinc and 99% of the lead in them. In comparison with the initial ore-tailings mixture, the resulting sublimates are 11.83 times richer in zinc.

Factors affecting conversion of methane-hydrogen mixtures into nanostructured carbon and hydrogen

At the catalytic decomposition of methane, along with hydrogen, it is possible to obtain carbon nanofibers. The addition of hydrogen to the initial reaction mixture makes it possible to increase significantly the efficiency of the overall process by minimizing the contribution of the catalyst deactivation process caused by coking. As found, the maximum yields of hydrogen and nanostructured carbon over the NiO–CuO/Al2O3 catalyst is achieved at an inlet hydrogen concentration of 13 vol%. The accumulated carbon is represented by well-structured carbon nanofibers, which are resistant to the gasification reaction. The original stacked structure is preserved after the treatment of these fibers in a hydrogen medium. Using numerical methods, the hydrogen productivity at 610 °C was found to be 49.3 mL/(mgcat·h) at an optimal value of the residence time of 5 × 10−3 s.