Composition Of Mixture Research Articles

Optimizing printability and mechanical properties of poly(3-hydroxybutyrate) (P3HB) biocomposite blends and their biological response to Saos-2 cells

Bone tissue engineering requires scaffolds with three-dimensional structures that facilitate vascularization and new tissue growth. 3D printing, especially through fused deposition modeling (FDM), has emerged as an effective method for creating complex structures with high reproducibility. Early research in this area demonstrated the potential of poly(ε-caprolactone) (PCL) and poly(L-lactide) (PLLA) scaffolds for bone regeneration. Recently, polylactide (PLA) and polyhydroxyalkanoates (PHAs) have garnered attention for their biocompatibility and ability to support cell proliferation. Among PHAs, poly(3-hydroxybutyrate) (P3HB) shows promise due to its intrinsic biocompatibility and resorbability, making it a candidate for FDM-based scaffold fabrication. In the presented study, we aim to develop and optimize a biocompatible P3HB-based composite material for bone tissue engineering, incorporating PLA, hydroxyapatite (HA), and the plasticizer Syncroflex3114 (SN) to enhance mechanical properties and printability. This composite was processed into filaments for 3D printing and characterized through thermal, mechanical, and biological evaluations. Using a design of experiment (DoE) approach, we investigated factors such as temperature performance, warping, degradation, and strength to determine the optimal composition for use in tissue engineering. Four optimal mixture compositions fulfilling the optimization criteria of having the most suitable properties for bone tissue engineering, namely the best printability and maximum mechanical properties,  were obtained. The mixtures were optimized specifically for minimum warping coefficient (0.5); maximum flexural strength (66.9 MPa); maximum compression modulus (2.4 GPa); and maximum compression modulus (2.3 GPa) with a warping coefficient of no more than one at the same time. In conclusion, the study shows a new possible way to effectively develop and test 3D printed P3HB-based scaffolds with specifically optimized material properties.

Mixing small proteins with lipids and cholesterol.

Many ternary mixtures composed of saturated and unsaturated lipids with cholesterol (Chol) exhibit a region of coexistence between liquid-disordered (Ld) and liquid-ordered (Lo) domains, bearing some similarities to lipid rafts in biological membranes. However, biological rafts also contain many proteins that interact with the lipids and modify the distribution of lipids. Here, we extend a previously published lattice model of ternary DPPC/DOPC/Chol mixtures by introducing a small amount of small proteins (peptides). We use Monte Carlo simulations to explore the mixing phase behavior of the components as a function of the interaction parameter representing the affinity between the proteins and the saturated DPPC chains and for different mixture compositions. At moderate fractions of DPPC, the system is in a two-phase Ld + Lo coexistence, and the proteins exhibit a simple partition behavior between the phases that depends on the protein-lipid affinity parameter. At low DPPC compositions, the mixture is in Ld phase with local nanoscopic ordered domains. The addition of proteins with sufficiently strong attraction to the saturated lipids can induce the separation of a distinct Lo large domain with tightly packed gel-like clusters of proteins and saturated lipids. Consistent with the theory of phase transitions, we observe that the domain sizes grow when the mixture composition is in the vicinity of the critical point. Our simulations show that the addition of a small amount of proteins to such mixtures can cause their size to grow even further and lead to the formation of metastable dynamic Lo domains with sizes comparable to biological rafts.

Miniaturized distillation device for detection of hydrocarbons using distillation curve principle

Abstract The objective of this study is to miniaturize the distillation apparatus to detect and analyze the composition of hydrocarbon mixtures. To achieve this, a micrometric chip measuring 150×100×6 mm3 was fabricated using a CO2 laser engraving machine. The chip, made of poly-methylmethacrylate, consists of a mini heater, condenser, and column. Its purpose is to separate hydrocarbons and determine the distillation curve of the mixtures. To assess its performance, three hydrocarbons (iso-pentane, 1-pentene, and n-hexane) were injected into the chip in different percentages ranging from 0 to 100%. These hydrocarbons were selected to represent pure, binary, and ternary compounds. The chip then analyzed the samples, and the distillation curves were obtained by plotting the boiling temperature against the percentage of condensed volume. The results of the experiments revealed that each distillation test lasted about 15 minutes. Despite the close boiling temperatures of iso-pentane and 1-pentene (27.8 and 30 °C, respectively), the chip could accurately identify the composition of different mixtures in the analyzed materials. The repeatability test demonstrated that the average standard deviation for the examined binary mixtures ranged from 1-2%, indicating the reliable reproducibility of the results. In conclusion, the miniaturized distillation chip that was fabricated can effectively analyze hydrocarbon mixtures and determine their purity.

ИСПОЛЬЗОВАНИЕ ТЕХНОЛОГИИ ГАЗОПЛАМЕННОГО НАПЫЛЕНИЯ ПРИ ИЗГОТОВЛЕНИИ ИНСТРУМЕНТОВ С АБРАЗИВСОДЕРЖАЩИМ ПОЛИМЕРНЫМ ПОКРЫТИЕМ

The possibility of forming abrasive-containing coatings based on ultra-high molecular weight polyethylene by flame spraying has been studied. Using the method of differential scanning calorimetry, it is shown that in the process of gas-flame spraying, particles do not reach the temperature range of thermal-oxidative destruction, and the basic structure of UHMWPE is preserved. The dependence of the adhesion strength of abrasive-containing coatings on their cooling rate and the composition of the propane-air mixture has been determined. Spraying modes have been determined for coatings containing abrasive particles from 0.3 to 1.2 mm, and coatings with abrasive from 10 to 100 μm. It is advisable to use the resulting coatings in the manufacture of various abrasive tools. It has been established that the introduction of a nanosized filler in the form of powdered diamond-containing charge ShA-A into the sprayed abrasive-polymer mixture makes it possible to increase the mechanical characteristics of coatings.

Temperature control and energy-saving efficiency evaluation of low-energy warm-mix asphalt mixtures with composite additives

Traditional warm-mix asphalt (WMA) faces challenges in reducing mixing temperatures to achieve lower energy consumption. To address this challenge and meet global environmental goals, this study designs various composite warm-mix additives using commonly used additives and their optimal dosages. The viscosity reduction mechanisms of asphalt and asphalt mixtures are examined using viscosity–temperature and air voids-temperature curves. Regression equations for viscosity and voids as a function of temperature are developed to determine the optimal mixing temperature of WMA. The study integrates thermodynamic equilibrium equations with field data to quantify the energy consumption in producing composite WMA mixtures. The results reveal that WMA significantly reduces mixing temperatures, making it suitable for low-energy asphalt mixtures. The use of various composite additives enhances the mechanical properties of asphalt pavements. Optimal mixing temperatures are set as 60–100 °C for WMA in warm-paving applications, and 20–60 °C for WMA in cold-paving applications. Viscosity ranges from 0.17 to 0.28 Pa⋅s, with air voids varying from 6%–7% for WMA in warm-paving applications and 8%–9% for WMA in cold-paving applications. Controlling the mixing temperature improves energy-saving efficiency, achieving reductions from 47.1% to 97.6%. The study recommends the use of WMA (Sasobit/Evotherm/DAT) for warm-paving applications and WMA (Sasobit/Diesel oil) for cold-paving applications. This study provides valuable insights for developing energy-efficient and high-performance asphalt pavements.

Numerical investigation of the influence of thermal runaway modelling on car park fire hazard and application to a Lithium-ion Manganese Oxide battery

This article presents numerical simulations of a Nissan LEAF 2011 electric car fire inside a concrete parking facility. Variations in the thermo-chemical properties of thermal runaway are analysed, and the way they affect the heat received by the concrete structure and a nearby parked vehicle is evaluated. Three key parameters are identified: the composition of the gas flowing through the pressure vent, the associated flow rate, and the peak heat release rate. These parameters are established independently, and the model is closed by adjusting the stoichiometry of the combustion reaction of the vented gas. Four simulations are conducted to capture the uncertainty. The net heat flux and surface temperature on the concrete and on a neighbouring parked car are monitored during each simulation. The study includes a sensitivity analysis of the impact of input variables on the net heat fluxes and surface temperatures, and investigations are carried out to understand the role of internal heat release. Variations in the gaseous mixture composition, heat release rate, and internal heat release have little impact on the resulting thermal conditions around the burning car because the combustion of the polymers in the passenger cabin drives the total heat release rate.

A detailed kinetic submechanism for OH* chemiluminescence in hydrocarbon combustion

Here, we propose a new physically consistent modeling scheme, JIHT-OHex(CxHy), that accurately predicts the formation and consumption of electronically excited chemiluminescent OH∗ molecules in hydrocarbon flames over a wide range of temperatures, pressures, and mixture compositions. It incorporates (unchanged) our recent well-founded JIHT-OHex(H2) reaction submodel (Sharipov et al., 2024, Combust. Flame, 263, 113417), aimed at describing the OH∗ evolution in hydrogen oxidation, and contains a necessary set of elementary processes involving OH∗ and carbon-containing species with the rate constants that are based either on a critical review of known, sometimes conflicting literature data on the elementary reaction kinetics of OH∗ or, where necessary and appropriate, on semiempirical estimates. To improve the JIHT-OHex(CxHy) performance against a representative data set for the observed OH(A2Σ+→X2Π) chemiluminescent emission (near 309 nm) accompanying high-temperature oxidation of various (from C1 to C10) hydrocarbon-based mixtures that we aggregated at the preparatory stage of the work, the rate coefficients of reaction and quenching processes that the overall OH∗ kinetics is most sensitive to (or for which there is a particular scatter in the available kinetic data, if any) were jointly optimized within their theoretical expectations and experimental uncertainties. It is shown that our universal detailed OH∗ submechanism, which includes a much larger pool of elementary processes (32 reactions and 36 quenching partners) than previous essentially global models (consisting of only a few processes and tailored to specific mixtures and combustion conditions), clearly outperforms the competitors in terms of integral accuracy (when tested against the multitude of the collected OH∗ emission measurements). Accordingly, there is reason to believe, as exemplified for the conditions of the laminar premixed methane-air flame, that our detailed OH∗ submodel with physically realistic (to the extent possible) rate constants will perform adequately over a wider range of burning conditions and flow parameters than that for which it was validated and tuned.Novelty and significance statementAlthough it is widely accepted that UV chemiluminescent OH(A2Σ+−X2Π) emission as an optical signature of the combustion process as a whole and of the underlying chemistry offers unique diagnostic capabilities, in recent years, definitely insufficient attention has been paid to the development of the detailed reaction mechanisms for quantitative interpretation of the OH∗ chemiluminescence measurements in various burning environments. This is especially true for the oxidation of hydrocarbons. Indeed, the pertinent OH∗ models known to date are essentially global, meaning that they all contain a surprisingly small number of processes (in most cases, only a couple of OH∗-forming reactions are involved alongside the quenching processes) and their rate constants are adjusted to specific hydrocarbon-based mixtures and burning conditions. Accordingly, a revision of the current understanding of the OH∗ kinetics in the presence of hydrocarbons is highly desired; therefore, our detailed physically-based reaction mechanism, which comprises dozens of plausible pathways of OH∗ formation and depletion with realistic rate coefficients and thus is capable of simulating the OH∗ emission in hydrocarbon flames more accurately than previous models, is in itself a fundamentally significant and novel contribution to the practice of chemiluminescence modeling. No less importantly, the rate constant fits, recommended here, are also of independent interest in the context of excited-state chemistry.

Consistent growth responses of silver fir (Abies alba Mill.) and European beech (Fagus sylvatica L.) to drought in mixed and monospecific forests: Insights from Central European forests

Ongoing climate change, characterized by an increased frequency of extreme weather events, including severe droughts, negatively impacts forest ecosystems. However, tree responses differ across tree species and stand composition (mixtures vs. pure stands), which may serve as an important management strategy for forest adaptation to climate change. To investigate the effect of stand composition on drought resilience, we conducted research on forest ecosystems in the Polish Outer Carpathians at the eastern edge of the distribution range of two important European tree species, silver fir (Abies alba) and European beech (Fagus sylvatica). The aim of our study was to identify climatic factors influencing the growth of these species and to examine their drought sensitivity and productivity. For this purpose, we sampled 100 fir and 100 beech trees from both mixed and monospecific stands. We applied a dendroclimatological approach to determine temporal stability of climate–growth relationships. Lloret’s resilience indices were used to quantify the response of tree growth to episodic drought stress, while to derive differences in productivity, we applied the generalized additive mixed models (GAMMs). Our results showed species specific climate sensitivity which remain consistent regardless of mixture only for fir. Fir responded positively to higher temperatures, especially during spring, but required more precipitation, particularly in summer. Beech exhibited lower sensitivity to climate in mixed than in monospecific stands and exhibited higher resistance than fir. Importantly, species responses to droughts were driven by the duration of specific drought event and the timing in which it occurred. Furthermore, our results revealed that mixed stands were more resistant to extreme drought events. Fir showed higher resistance to extreme drought events in mixed stands than in pure stands. Overall, silver fir exhibited higher productivity than European beech. Especially in younger cohorts, it was higher for pure stands, but fir from mixed stands exhibited increasing productivity with age and delayed culmination. Our findings indicate that both species can form resilient stands in the studied region, making them viable for forest management in the face of climate change. Mixtures of fir and beech are particularly valid option to promote forest sustainability and productivity in mountain regions. Managed mixed stands of Abies alba and Fagus sylvatica demonstrated advantages in productivity and stability under extreme drought conditions. However, varying intensities of management interventions and structural differences between stands and among studies complicate direct comparisons, highlighting the need for more standardized approaches to analyzing species responses and management strategies in the future.

Comparative study of physical and mechanical properties of a light plaster mortar based on the "SPADAR" foam ceramic granules and similar light fillers

Introduction. Plasters are still one of the most popular materials for finishing of facades of buildings. Modern plasters are produced mainly in the form of ready-to-use dry mixes. Manufacturers set themselves the task of obtaining not only plaster mixtures meeting standards, but also having hydrophobicity, low density, thermal conductivity and other features that determine the functionality of the plaster coating. In this regard, there is a need to develop and implement plaster mixtures based on new types of light aggregates. Aim. To conduct comparative studies of the physical and mechanical properties of a light plaster mortar using the "SPADAR" foam ceramic granules and plaster mortars with similar fillers as a light filler. Materials and methods. The research was carried out on light plaster mortars using as light fillers: "SPADAR" and foam ceramic granules from another manufacturer ("KERWOOD"), foam glass granules, expanded perlite sand. The parameters of density, strength under axial compression, water absorption during capillary suction and thermal conductivity of a light plaster mortar in a dry state were studied. The tests were carried out according to standard methods. Results. The comparative technical characteristics of the studied plaster compositions are determined. During the analysis of the data obtained, the advantages of plaster compositions using foam ceramic granules as a light filler were revealed. Based on the data obtained, the composition of a light plaster mortar with a density of up to 700 kg/m3 using the "SPADAR" foam ceramic granules was developed. Conclusions. The composition of the plaster based on the "SPADAR" foam ceramic granules turned out to be the most effective by the obtained values of the studied characteristics in total. In many ways, the obtained values of the technical characteristics of this plaster studied in this work are provided precisely by the "SPADAR" foam ceramic granules. Based on the results obtained, it is necessary to investigate other properties of the developed compositions of light plaster mixtures (adhesion, vapor permeability, moisture-proof properties with respect to the mineral base, frost resistance, etc.).

In-situ thermite combustion of micro magnesium fuel and lunar regolith simulant nanoparticles

Significant heat generation will be required for humans and equipment to the lunar night. In this work, we investigate the use of a sustainable in-situ thermite material as a fuel to provide the thermal energy required to keep components in working conditions. Magnesium is used as a reactive metal fuel, with lunar regolith simulant ball milled to sub-micron sizes as a solid oxidizer producing exothermic reactions. Enhanced combustion is achieved by controlling particle size and composition of the thermite mixture. Simulant particles ranging from hundreds of nanometers to tens of microns in diameter are tested, as well as the magnesium fuel compositions of 20% to 40% by weight. Small pellets of 3 mm in diameter and 3 mm in height are ignited by laser in both air and vacuum to quantify the combustion properties in different environments. High speed video, infrared camera and pyrometry techniques are taken to quantify the sample combustion properties. These pellets demonstrate the burning rates between 2.3 and 5.9 mm/s and temperatures ranging from 1100 to 1480 °C in vacuum and in air conditions, respectively. The samples composed of 20% magnesium and 80% regolith simulant release around 400 J/g, and sustain elevated temperatures for 15 s after combustion, making them suitable for in-situ lunar heating. Novel 2D temperature mapping allows greater understanding of the simulant thermite combustion. Based on the results, we discuss the design considerations that would need to be made in the creation of an in-situ metal fuel heating lunar system.

Groundwater potential in mining regions for drinking water supply: A case study of the Żelatowa intake (Chrzanów, Poland)

Sustainable development of groundwater resources in regions affected by mining activity requires a comprehensive view of the problem from both a hydrogeological and hydrogeochemical perspective. As groundwater serves as a main source of drinking water in many regions of the world, it is necessary to recognise the potential of mine waters and their real influence on its quality. This study analyses the long-term dynamics of changes in drinking water quality from deep wells S1, S2, and S3 comprising the Żelatowa intake (Chrzanów, Poland), which is located in an area of intensive mining activity. Analysis of the data showed that mining operations are affecting water quality, as observed by upward trends for electrical conductivity, total hardness, and concentrations of certain ions between 2016 and 2021, and downward trends from 2022 onwards. The greatest adverse changes in water quality were observed in well S2 (Fe2+, Mn2+, SO42− concentrations and total hardness do not meet the requirements of Directive 2020/2184), the water requiring mixing with water from other wells to ensure that it is of suitable quality for drinking purposes. The PHREEQC software was successfully used to predict the chemical composition of the final mixture, which meets the requirements of appropriate regulations. The water from the Żelatowa intake can have an adverse effect on the water supply system, which has been proven by several scaling and corrosion indices. Continuous monitoring of the physicochemical parameters of these waters is essential to ensure the safety of the drinking water supply for the surrounding population.

Thermodynamic Fluorescence Behavior of a Fluorenone Derivative through Solvent‐ and Temperature‐Controlled Hydrogen Bonding

A fluorenone derivative with an extended conjugated structure emitting visible light was examined as a functional fluorescent dye that responds to solvent and heat stimuli in a precisely controlled manner. Intermolecular hydrogen bonds between the fluorenone dye and solvent, which cause fluorescence (FL) quenching due to vibronic coupling, were broken and regenerated by adjusting the hydrogen bond acidity and basicity of solvent mixtures in various combinations or by varying the temperature. The fluorenone dye exhibited a unique heat‐induced FL emission enhancement during heating and returned to the quenched state during cooling. Thus, this FL change was highly reversible and repeatable. Moreover, through thermodynamic consideration based on the spectroscopic analysis, the Gibbs energy change was calculated for each solvent mixture composition to predict the thermodynamic preference for FL enhancement.

Evidence from In Situ Bioassays and Suspect Analysis Revealed the Region-Specific Aquatic Risk across Socioeconomic Gradients in China.

Various contaminants are present in aquatic environment and pose potential threats to pelagic and benthic organisms, calling for effective risk assessment. Traditional risk assessments based on target analysis are useful when the principal contaminants responsible for ecological risk are known; however, these approaches become challenging when dealing with chemical mixtures. In addition, the compositions of chemical mixtures often differ in regions with different levels of socioeconomic development, requiring risk assessment methods that are applicable under different pollution scenarios. Herein, in situ bioassays were conducted with two native species, Chinese rare minnows (Gobiocypris rarus) and Asian clams (Corbicula fluminea), in economically developed watersheds in China (Pearl River Basin (PRB) and Taihu Lake Basin (THB)) and agriculture-dominated Poyang Lake Basin (PYB). Significant lethal and sublethal effects (e.g., neurotoxicity, reproductive toxicity, and metabolic and oxidative stress) were observed in fish and clams irrespective of economic gradients. Notably, ecological effects differed significantly between water and sediment phases within the same region. Target (98 contaminants) and suspect screening (942 contaminants) revealed regional-specific characteristics. Ecological risk assessments using a weight of evidence approach demonstrated that both water and sediment in the PRB were at moderate to high risk, as was the sediment in the less developed PYB. However, the characteristics of mixture pollution varied greatly among regions. Suspect screening identified many pollutants that are not regularly monitored but are present at high environmental concentrations and are linked to local industrial production. These distinct mixture risk characteristics across different basins suggest that mitigating aquatic pollution requires region-specific management measures.

Experimental Analysis of Long-Term Fuel Trim Performance in a Gasoline Engine Under Various Operating Conditions

This paper analyzes the effect of operating conditions on the enrichment of the fuel-air mixture in a car engine due to a decrease in air mass with increasing altitude above sea level. This study focuses on fuel trim, particularly long-term fuel trim, in optimizing the composition of the fuel-air mixture before it enters the engine's combustion chamber. Experimental studies were conducted on the Bishkek–Osh highway in the Kyrgyz Republic, a road characterized by flat, mountainous, and high-altitude sections with complex terrain. Based on the research objectives, experimental results were obtained, and graphs of long-term fuel trim as a percentage of terrain altitude were constructed and analyzed for flat, mountainous, and high-altitude sections of the Bishkek–Osh highway. The study established that fuel trim indicators can be used to analyze changes in the air-fuel mixture's air excess coefficient (λ = 1, stoichiometric ratio). The reduction in long-term fuel trim was observed in flat, mountainous, and high-altitude sections as air density and pressure decreased with increasing altitude above sea level. The results show that with a reduction in long-term fuel trim to -6.25% to -7.81% at altitudes between 1500 and 3000 meters above sea level, the air excess coefficient (λ) drops to 0.92–0.94. At an altitude of 770 meters (flat terrain), λ was measured at 0.97. The difference in λ (0.03–0.05) indicates that an increase in altitude significantly affects the air-fuel ratio (AFR), impacting mixture formation during vehicle operation in mountainous and high-altitude conditions.

CALCULATION AND EXPERIMENTAL DEPENDENCIES OF INITIAL CARBONATION OF CONCRETE COMPRESSIVE STRENGTH CLASSES C12/15...C50/60

The article substantiates the need to study the preliminary carbonization of concrete. Based on laboratory studies of concrete samples of compressive strength classes С12/15…С50/60, mixture compositions of workability grades P1 (OK = 4 cm), a system of calculated and experimental dependencies of initial carbonization КС0 = f(Ц) was obtained. The dependencies were checked using mathematical statistics methods, which showed the adequacy of the obtained dependencies. Obtained depending on the preliminary carbonization КС0 = f(fG c,cube) on the guaranteed compressive strength of concrete for mixtures of workability grade P1. By mathematical processing of the dependence coefficients derived from the dependence of the initial carbonization КС0 = f(Цр) and КС0 = f(fG c,cube) for classes of concrete in terms of compressive strength С12/15…С50/60, mixture compositions of workability grades G1 (8 s) and G2 (15 s).

Flame Speed Measurements of Ammonia–Hydrogen Mixtures for Gas-Turbines

Abstract Recent findings from the U.S. Energy Information Administration project an increase in domestic fossil fuel consumption (e.g., petroleum and natural gas) and global greenhouse gas emissions through 2050 (Nalley, S., 2021, “International Energy Outlook 2021 (IEO2021),” IEO2021 Release, CSIS, Center for Strategic and International Studies, Washington, DC, Technical Presentation, pp. 2–12). Consequently, advanced combustion research aims to identify fuels to mitigate fossil fuel consumption while minimizing exhaust emissions. Ammonia (NH3) is one of these candidates, as it has historically been shown to provide high energy potential and zero-carbon emission (CO and CO2) (Hayakawa, A., Goto, T., Mimoto, R., Arakawa, Y., Kudo, T., and Kobayashi, H., 2015, “Laminar Burning Velocity and Markstein Length of Ammonia/Air Premixed Flames at Various Pressures,” Fuel, 159, pp. 98–106). As a hydrogen (H2) carrier, NH3 serves as a possible solution to the U.S. Department of Energy's Hydrogen Program Plan by providing efficient H2 storage and conservation capabilities (U.S. Department of Energy, 2020, “Department of Energy Hydrogen Program Plan,” U.S. Department of Energy, Washington, DC, Report No. DOE/EE-2128). As a result, applied turbine-combustion research of NH3 and H2 fuel has been conducted to identify combustion performance parameters that aid in the design of sustainable turbomachinery (Chiong, M.-C., Chong, C., Ng, J., Mashruk, S., Chong, W., Samiran, N., Mong, G., and Medina, A., 2021, “Advancements of Combustion Technologies in the Ammonia-Fuelled Engines,” Energy Convers. Manage., 244, p. 114460). One of these key combustion parameters is the laminar burning speed (LBS). While abundant literature exists on the combustion of NH3 and H2 fuels, there is not sufficient evidence in high-pressure environments to provide a comprehensive understanding of NH3 and H2 combustion phenomena in turbine-combustor settings. To advance the state of the knowledge, NH3 and H2 mixtures were ignited in a spherical chamber across a range of equivalence ratios at 296 K and 5 atm to understand their flame characteristics and LBS which was determined using a multizone constant volume method. The experimental conditions were selected according to primary turbine-combustor conditions, as much research is needed to support NH3–H2 applicability in turbomachinery for power generation. The effect of H2 addition to NH3 fuel was observed by comparing the LBS for various NH3–H2 mixture compositions. Experimental results revealed increased LBS values for H2 enriched NH3, with the maximum LBS occurring at stoichiometry. The experimental data were accurately predicted by the University of Central Florida (UCF) NH3–H2 mechanism developed for this investigation, while NUI 1.1 simulations overestimated recorded LBS data by a significant margin. This study demonstrates and quantifies the enhancing effect of H2 addition to NH3 fuels via LBS and strengthens the literature surrounding NH3–H2 combustion reactions for future work.

Assessment of cationic amphiphile-biopolymer interactions: Effects of organic compounds and temperature on association phenomena

The present study reveals the micellization nature of cetyltrimethylammonium bromide (CTAB) in aqueous solutions of sodium alginate (SA) with short-chain alcohols (containing 1–3 carbon number) and glycerol using the conductometric method at temperatures from 305.55 to 325.55 K with 5 K interval. The aggregation property has been characterized by assessing critical micelle concentration (CMC) from conductivity (κ) versus surfactant concentration plots. The micellar variables such as CMC and the extent of counterion binding (β) demonstrate the dependency on the variation in solvent categories, composition of the solvent mixture, and working temperatures. For the CTAB + SA (0.01 %, w/w) mixed system at 310.55 K, the increased CMC values were acquired with increasing quantity of alcohols and glycerol introduced. The CMC values showed a rising trend with the escalation of working temperature. The negative Gibbs free energy (ΔGm0) values were attained for the CTAB + SA system in all investigating solvents, which stated the spontaneous occurrence of aggregation of the employed system. In aqueous alcohols media, the enthalpy changes (∆Hmo) were attained as positive and negative at lower and elevated investigated temperatures respectively; while in aqueous glycerol environment, the ∆Hmo values were acquired to be all negative at inspected temperatures. The entropy changes (∆Smo) were realized to be positive for the investigated cases. The compensation temperature (Tc) values have been achieved to be in the series of 241.91 K to 318.75 K which showed a good analogy to the literature stated data for the micellization of amphiphiles. The attained knowledge from the present investigation might help in improving the formulations in industries including pharmaceuticals, foods, and cosmetics.

Micellar solubility and co-solubilization of fragrance raw materials in sodium dodecyl sulfate and polysorbate 20 surfactant systems.

The aim of this work was to investigate the solubility and co-solubilization of fragrance raw materials (FRMs) in sodium dodecyl sulfate (SDS) and polysorbate 20 (P20) surfactant micellar systems, which can advance our knowledge of multi-solute micellar solubilization and fragrance olfactory performance from product matrices containing the surfactants. The transfer of individual FRMs and binary FRM mixtures into micellar phases was quantified by UV-VIS differential spectroscopy and evaluated in terms of the standard Gibbs free energy change and micelle-water partition coefficient. Co-solubilization effects were further evaluated by the deviation ratio. Anionic SDS was found overall to be a more efficient solubilizer than nonionic P20. On an individual basis, micellar solubilization generally increased with solute lipophilicity but was additionally impacted by solute rigidity and steric effects. Micellar solubilization was favoured for more rigid structures and less favoured for FRMs that exhibited larger molecular rotation and steric hindrance. For multi-solute systems, three co-solubilization effects were observed: (i) inhibitive effect in which micellar partitioning of both solutes decreased, (ii) an inverse effect where partitioning of one solute increased while the other decreased and (iii) synergistic effect in which partitioning of both solutes increased. During co-solubilization in P20 micelles, many FRMs competed for solubilization between the polyoxyethylene chains in the outer layer of the micelle, thereby resulting in an inhibitory effect for both solutes. Co-solubilization of FRM binary mixtures in SDS micelles often resulted in a synergistic increase in micellar solubility, possibly due to micellar swelling, thereby facilitating partitioning of additional solutes into the micelle. An inverse effect in which the micellar solubility of one solute increased, while the other decreased was observed in both surfactant systems with varying degrees of partitioning depending on the composition of the FRM mixture. The results of this study provide valuable insights into the impact of FRM composition on multi-solute partitioning behaviour and the impact of surfactant type on co-solubilization in micellar solutions.

Thermal Runaway of Na‐Ion Batteries with Na3V2O2(PO4)2F Cathodes

AbstractThe metal‐ion battery manufacturing growth rates increase attention to the safety issues. For promising sodium‐ion batteries, this topic has been studied in much less detail than for the lithium‐ion ones. Here, we explored the thermal runaway process of Na‐ion pouch cells with the Na3V2O2(PO4)2F (NVOPF)‐based cathode. The thermal runaway onset temperature for such cells is noticeably higher than that for the NMC‐based LIBs. We show that thermal runaway is triggered by the anode and the separator decomposition rather than by the processes at the cathode. The composition of the gas mixture released during thermal runaway process is similar to that for Li‐ion batteries. The results suggest that sodium‐ion batteries based on polyanionic cathodes can pave the way to safer metal‐ion energy storage technologies.

Ensuring the stability of spectrophotometric measurement results during analysis of mixtures composition

Spectrophotometric methods for studying the composition of mixtures are considered. The need to increase the stability and accuracy of the results of spectrophotometric measurements when analyzing substances with low absorption coefficients or a low concentration of the determined substance is shown. A spectrophotometric complex with a thermostated cell is described, which enables to study gaseous and liquid mixtures. Results of study at this complex of absorption spectra of isomers of liquid xylene and their mixtures are given. Methods of increasing the stability of spectrophotometric measurement results, hardware and data processing methods necessary for this are considered. It has been shown that thermostating of not only vaporous, but also liquid samples is one of the necessary conditions for ensuring the stability of measurement results. The procedure for performing experiments and processing the results of spectrophotometric measurements is presented. A differential method has been developed to reduce the impact of spectrophotometer signal instabilities on the accuracy of determining the composition of mixtures. The method consists in using as input data for multiple linear regression not the absorption spectrum, but its wavelength derivative. An analysis of the composition of mixtures of two xylene isomers showed that the use of this method can reduce RMS of determining the composition of mixtures by about 1.6 times. It is noted that additional filtering (smoothing) of the measured absorption spectrum derivative may be required to reduce errors in determining the composition of mixtures. The developed method of reducing the influence of the spectrophotometer signal instabilities on the results of the mixture composition analysis is of the greatest interest for the analysis of substances with low absorption coefficients or in the case of low concentrations of the studied substances and can be used to solve environmental monitoring problems, for example, when determining hydrocarbon contaminants in the atmosphere.