Initial Temperature Research Articles

A comparative study of machine learning approaches for predicting viscosity in Sacran/CNF solutions

This study explores the predictive capabilities of machine learning algorithms for Sacran/CNF solution viscosity. Leveraging data on initial CNF amount, shear rate, shear stress, speed, torque, and temperature, decision tree (DT) and random forest (RF) models were employed. Both models demonstrated strong alignment with experimental results, achieving a coefficient of determination (R2) of 0.99. The main features of those models established that 60 % of the importance is attributed to speed or shear rate, while 31 % is attributed to the ratio of CNF content in the solutions. This research underscores the potential of machine learning in effectively analyzing viscosity datasets.

Influence of char‐forming lignin in combination with aluminium phosphinate on thermal stability and combustion properties of polyamide 11 blends

AbstractPolyamide 11 (PA) blends based on char‐forming industrial lignin and aluminum phosphinate (AlP) were prepared to improve flame retardant (FR) properties using a green and eco‐friendly approach. This study investigates the thermal degradation and combustion behavior of PA blends prepared by using AlP in combination with two different types of industrial lignins (i.e., kraft lignin (DL) and lignosulphonate lignin (LL). Thermogravimetric (TG) analysis showed that ternary blends containing LL and AlP developed higher char residue up to 10.7 wt% upon decomposition in inert atmospheres. The combination of lignin and AlP increases the thermal stability by shifting the initial decomposition temperature (T5%) and temperature at maximum decomposition (Tmax) to a higher temperature range, attributed to the stabilization of decomposition products. Furthermore, combustion behavior studied by cone calorimeter (forced combustion) and pyrolysis combustion flow calorimeter (PCFC) tests presented a significant reduction in the peak of heat release rate (PHRR) and total heat release (THR). It was found that LL and AlP‐containing blends more effectively decreased fire parameters like PHRR and THR than that of DL and AlP‐containing blends. The best interaction with reduced fire‐retardant properties was obtained when 10 wt% loading of lignin (DL/LL) and AlP was used. The reduction in heat release parameters was mainly ascribed to the condensed phase mechanism by forming an efficient protective char layer, which acts as a barrier against heat and mass transfer between the condensed and the gas phases. Raman spectroscopy analysis also confirmed the formation of the protective graphitic layer in the condensed phase.

Multi-objective optimization design and sensitivity analysis of proton exchange membrane electrolytic cell

Proton exchange membrane electrolytic cells (PEMECs) are considered cleaner energy-conversion devices with potential commercial applications in hydrogen production. However, the heat- and mass-transfer characteristics inside the cell remain unclear, and its performance should be optimized to achieve future commercial applications. A three-dimensional multi-physical field-coupling model is developed for the PEMEC. Subsequently, a multi-objective optimization design is used to optimize the structural and operational parameters of the cell based on a neural-network regression model. The results of the sensitivity and response-surface analyses indicate that the initial working temperature has the most significant impact on the reaction temperature, the current density is increased by up to 65.22% under the coupling effects of temperature and flow rate. The cell performance is also enhanced by the increased channel width and depth, although this is accompanied by limitations. Under the combined effects of increasing the working temperature and channel width or height, the current density can be increased by a maximum of 65.22% and 38.61%, respectively. The improvement in cell performance requires a trade-off between improved mass and heat transfer and larger pressure drop, and the optimal design achieves this trade-off. In optimal design, the current density is improved by up to 16.56%, the oxygen mass fraction of the catalytic layer is reduced by 40.90% compared with the original design, accompanied by a reasonable pressure drop and uniform temperature distribution. This study provides a novel perspective for the optimization of the PEMEC to promote its commercial application, offering a reference for further advanced optimization of cell performance and reducing trial-and-error costs. It is also expected to have practical applications in energy conservation and sustainable development.

Evaluation of thermal, antimicrobial, antioxidant, anticancer, and wound healing properties of GO-Ag containing nanocomposites based on CS- PPFOEMA blend

The new methacrylate-based polymer, poly (pentafluorophenyl)methyl 2-methylprop-2-enoate (PPFOEMA), was blended with CS biopolymer by in situ/hydrothermal method. The nanohybrid filler containing commercial graphene oxide (GO) and biosynthesized silver nanoparticles (AgNP) was incorporated into the CS-PPFOEMA mixture by hydrothermal treatment. PFOEMA and PPFOEMA were characterized by FTIR and NMR techniques, while the nanocomposites were characterized by FT-IR, XRD, SEM, and EDX analysis. The thermal properties of the materials were determined by TGA and DSC techniques. According to TGA data, PPFOEMA caused a decrease in the thermal stability of CS. However, the thermal stability increased after the incorporation of GO-AgNPs into the blend by hydrothermal method. The initial degradation temperature of the CS-PPFOEMA blend, which was 240 °C, increased to 260 °C after adding 7 % GO-Ag. The glass transition temperature (Tg) of CS decreased after blending and after the incorporation of GO-AgNPs into the blend. The antioxidant capacity (TAC) of the GO-AgNPs mixture was close to that of CS-PPFOEMA, but TAC levels increased with the inclusion of GO-AgNPs in the CS-PPFOEMA blend. While the cytotoxicity of CS in A549 cells was 100 μg/mL, it became 100 μg/mL after blending. Additionally, when GO-Ag was added to the CS-PPFOEMA mixture at different rates, toxic effects were observed starting from 100 μg/mL concentration. The nanocomposite containing 3 % GO-Ag was highly influential in wound healing. The results are promising for using nanocomposites formed by blending CS with synthetic PPFOEMA and adding GO-Ag NPs as safe biomaterials.

The mechanism and behavior of cesium adsorption from aqueous solutions onto carbonated cement slurry powder

In this study, microstructural differences and changes in the adsorption capacity of cesium between cement and carbonated cement were investigated. Cement blocks were ground to powder for rapid carbonation, and microscopic variations were characterized by XRF, XRD, FT-IR, SEM, BET, and TGA. The characterization results show that the conversion of Ca(OH)2 and calcium silicate hydrate (C–S–H) gel to CaCO3 in cement after carbonation. And the component of Ca(OH)2 in the powder sample disappeared after three days of rapid carbonation. Batch experiments were used to investigate adsorption under the influence of time, initial cesium concentration, temperature, and ion coexistence. Pseudo-second-order kinetic and Langmuir isothermal model fitting could better describe the adsorption process and the results show that the maximum adsorption capacity of cement after carbonation surges from 29.6 μg‧g−1 to 1.58–5.89 mg‧g−1. (Different carbonating times lead to varying adsorption capacity.) The adsorption capacity decreases with increasing temperature. At temperatures of 293 K and 333 K, the calculated Gibbs free energy change values of cement with different carbonated degrees adsorbing cesium are −10.3 ∼ −14.9 kJ‧mol−1 and -8.03 ∼ −12.4 kJ‧mol−1. And the calculated values of enthalpy change and entropy change are −18.8 ∼ −23.8 kJ‧mol−1 and –27.9 ∼ –37.1 J‧mol−1‧K−1. Combining the characterization and adsorption results, the huge increase in cesium adsorption capacity is closely related to the conversion of Ca(OH)2 to CaCO3, which will provide a new perspective on the adsorption mechanism of cesium in cement.

Investigation of gradient band gap in Cu2ZnSnS4 thin films with residual strain

This study investigates the change in the band gap of Cu2ZnSnS4 (CZTS) thin films under a gradual change in the residual strain of the thin films. Two CZTS thin film samples are fabricated at different initial substrate temperatures before annealing. X-ray diffraction results are obtained at various incidence angles, and the residual strains at the incidence angles are obtained from the Williamson–Hall plot. The larger the mean residual strain of the CZTS thin films, the greater are the redshift and full width at half maximum of the main Raman peak position. Results of Tauc plot analysis show that the CZTS thin film samples exhibit a gradient band gap. The sample with a wider distribution of the residual strain shows a greater band gap variation.

Estimation and testing of single-step oxidation reactions for hydrogen and methane in low-oxygen, elevated pressure conditions

Advanced combustion concepts, such as moderate or intense low-oxygen dilution (MILD) combustion, offer a reduction in NOx emissions and increased thermal efficiency. MILD is characterised by low-oxygen, high-temperature conditions, where finite-rate chemistry effects are significant. Modelling this regime using reduced or single-step chemistry remains a challenge in part due to the finite-rate chemistry. This work proposes a generalised method for assigning Arrhenius coefficients of a single-step reaction using the outputs of a detailed mechanism. Assigning the typical chemical conservation equation to a progress variable, activation energy and pre-exponential factor for an Arrhenius kinetics global reaction are determined for hydrogen and methane across a number of conditions, with the proposed method extended to n-heptane as well. The temperature exponent in the modified Arrhenius equation is determined by minimising the ignition delay error between detailed and single-step simulations. Functional forms of each coefficient are calculated from a multivariate regression, dependent on initial temperature, pressure, and oxidant mole fraction. The predicted mechanisms are compared against the detailed kinetics in closed homogeneous batch reactors, with comparisons for hydrogen extended to both laminar opposed flow diffusion flames, and computational fluid dynamics (CFD) simulations. Ignition delay and equilibrium temperature are both well predicted for all three fuels in the batch reactors. Notably, the negative temperature coefficient behaviour of n-heptane is successfully recreated with the single-step mechanism. Temperature and heat release of hydrogen flames are well captured in both opposed flow laminar flames, and in turbulent CFD simulations. The computational time was also significantly reduced through the single-step mechanisms, resulting in ∼100 times reduction in compute time for CFD simulations. The function form of the Arrhenius coefficients shows promise for extension outside of the ranges and fuels analysed herein, and presents interesting phenomena for exploring how initial reactant temperature and pressure influence the effective activation energy of an oxidation process.

Modeling strain-induced martensitic transformation in austenitic stainless steels subjected to cryogenic temperatures using incremental mean-field homogenization schemes

Austenitic stainless steels are commonly used as structural materials in high-field superconducting magnet systems because they retain high strength, ductility, and toughness at very low temperatures, and they are paramagnetic or antiferromagnetic under the Néel temperature in their fully austenitic state. However, they are susceptible to strain-induced martensitic transformation, especially at cryogenic temperatures, which modifies the material properties, induces volume changes and additional strain hardening, and leads to ferromagnetic behavior. Thus, accurate predictions of the structural performance of these materials at very low temperatures are of great interest for the conception and design of these cryo-magnetic systems. In this paper, we propose an adequate constitutive model for the evolving bi-phase material—austenite and martensite—based on a Hill-type incremental formulation. Two different versions of the model are proposed based on the linear mean-field homogenization scheme: Mori-Tanaka and Self-Consistent. Moreover, a rate-independent nonlinear mixed kinematic-isotropic hardening law is used for each phase, and the martensitic transformation is described by the nonlinear kinetic law proposed by Olson and Cohen (1975). The constitutive model is implemented in ABAQUS/Standard through a UMAT user subroutine, for which a return mapping algorithm based on the implicit backward Euler integration scheme is used and a closed-form expression of the consistent Jacobian tensor is provided. The Mori-Tanaka and Self-Consistent approaches are evaluated in terms of their ability to describe the mechanical behavior of the bi-phase aggregate by comparing the predictions of the homogenization schemes with unit-cell finite element calculations with an explicit description of the martensite inclusions and the austenite matrix. The comparison is carried out for different stress states with controlled triaxiality and Lode parameter under monotonic and cycling loading, paying special attention to the evolution of the mechanical fields in each phase. The unit-cell calculations are performed for both constant and evolving martensite volume fractions. In addition, numerical simulations of tensile tests on samples subjected to different initial temperatures are carried out for the transforming bi-phase material and the results are compared to experimental data for AISI 304L and AISI 316LN steels.

Study of the influence of external heat and mass exchange on the features of combustion and extinction of gas suspensions of carbon particles

In the work, the regularities of the influence of heat and mass exchange of gas suspensions of carbon particles with the external gas environment on the processes of ignition, burning and quenching at different mass concentrations of carbon fuel are studied. A monodisperse gas suspension of carbon particles located in a gas heated to a high temperature, which contains an oxidant, is considered. As a result of the conducted physical and mathematical modeling, the following characteristics of high-temperature processes were determined: induction period, burning time and time of complete transformation of particles, critical parameters of ignition and extinction of particles. The influence on these characteristics of the initial particle diameter, mass concentration and temperature of the surrounding gas was analyzed. It was found that the external heat and mass exchange has a slight effect on the induction period and critical parameters of the ignition of gas suspensions, but it has a sufficiently strong effect on the characteristics of the combustion and extinguishing processes. The existence of an upper limit for fuel concentrations and particle diameters at which complete combustion of gas suspensions is not observed in the absence of external mass transfer is proved. Ranges of mass concentrations were found for which complete conversion of carbon fuel burning in the form of gas suspensions is carried out. It is shown that for open gas suspensions, the range of mass concentrations, where complete transformation of particles is observed, expands to the side of large values. The diameters of the particles characterizing the quenching of gas suspensions, taking into account the external mass transfer, are smaller, as a result of a greater supply of oxygen to the volume of the gas suspension.

An Amphiphilic Multiblock Polymer as a High-Temperature Gelling Agent for Oil-Based Drilling Fluids and Its Mechanism of Action.

Oil-based drilling fluids are widely used in challenging wells such as those with large displacements, deepwater and ultra-deepwater wells, deep wells, and ultra-deep wells due to their excellent temperature resistance, inhibition properties, and lubrication. However, there is a challenging issue of rheological deterioration of drilling fluids under high-temperature conditions. In this study, a dual-amphiphilic segmented high-temperature-resistant gelling agent (HTR-GA) was synthesized using poly fatty acids and polyether amines as raw materials. Experimental results showed that the initial decomposition temperature of HTR-GA was 374 °C, indicating good thermal stability. After adding HTR-GA, the emulsion coalescence voltage increased for emulsions with different oil-to-water ratios. HTR-GA could construct a weak gel structure in oil-based drilling fluids, significantly enhancing the shear-thinning and thixotropic properties of oil-based drilling fluids under high-temperature conditions. Using HTR-GA as the core, a set of oil-based drilling fluid systems with good rheological properties, a density of 2.2 g/cm3, and temperature resistance up to 220 °C were constructed. After aging for 24 h at 220 °C, the dynamic shear force exceeded 10 Pa, and G' exceeded 7 Pa, while after aging for 96 h at 220 °C, the dynamic shear force exceeded 4 Pa, and G″ reached 7 Pa. The synthesized compound HTR-GA has been empirically validated to significantly augment the rheological properties of oil-based drilling fluids, particularly under high-temperature conditions, showcasing impressive thermal stability with a resistance threshold of up to 220 °C. This notable enhancement provides critical technical reinforcement for progressive exploration endeavors in deep and ultra-deep well formations, specifically employing oil-based drilling fluids.

Objective characterisation of reinforced concrete with progressive corrosion defects through clustering and thresholding of infrared images

The research in this paper focuses on detection and quantification of subsurface damage in reinforced concrete (RC) structures by the analysis of infrared images. Experimental investigations were performed on RC slabs with embedded reinforcing bars (rebars). The corrosion mechanism in rebars was accelerated using an electrical circuit setup. The initial temperature of the slabs was adjusted in the environmental chamber and IR images were taken at regular intervals while they were exchanging heat to laboratory air through convection. Records of IR images were post-processed using an objective thresholding method proposed based on unsupervised k-means clustering. The results were discussed in context and with respect to the ASTM D 4788–03 recommendation for minimum detectable thermal contrast (0.5 °C) from delamination in bridge concrete by infrared thermography (IRT). The conclusions lead to recommendations for improved practical implementation of IRT that contribute to the broader prospects of structural health monitoring (SHM).

Improving the combustion efficiency and agglomeration of aluminum-water propellants via n-Al/CuO metastable intermolecular composites

In this work, we investigated the combustion and agglomeration characteristics of aluminum-water propellants by replacing the original Al with binary n-Al/CuO metastable intermolecular composites (MICs). Through laser ignition tests and thermogravimetric-differential scanning calorimetry, we evaluated the oxidation reactivity, ignition delay, burning rate, agglomeration properties, and condensed combustion products of aluminum-water propellants containing different CuO loadings. Compared with conventional aluminum-water propellants, the introduction of binary MICs is found to lower the initial temperature of Al and improve its oxidation activity. Both the burning and heating rates scale linearly with the CuO loading, increasing by a factor of 5 and 6, respectively, when the CuO loading reaches 5 wt.%. The combustion efficiency of the modified propellants is found to improve by 5−12 %. The mean size of the condensed combustion products drops from over 400 μm to around 200 μm due to MICs addition, indicating weakened agglomeration. The ignition delay time is slightly shortened, and the combustion intensity first increases but then decreases as the CuO loading increases. In summary, this work indicates that replacing Al with binary Al/CuO-MICs can significantly alter the combustion and agglomeration properties of aluminum-water propellants. The experimental data and insight from this work could help guide the development of advanced aluminum-water propellants for various propulsion and energy applications.

Role of boiling for the formation of vertical metal zoning and bonanza zone in low-sulfidation epithermal gold‑silver deposits: A geochemical modeling approach

Boiling and mixing are thought to be the most important processes for mineralization in the low-sulfidation epithermal gold‑silver deposits. Some low-sulfidation epithermal gold‑silver deposits show vertical zoning of metals including gold, silver, copper, lead, and zinc, but effect of boiling and mixing for the vertical zoning of metals through mineralization has been scarcely debated. Therefore, we applied geochemical modeling for an open-isenthalpic boiling system, with a hydrothermal fluid with different initial temperatures, carbon dioxide contents, salinities, and total sulfur contents to numerically evaluate the effect of boiling phenomenon for the vertical zoning in low-sulfidation epithermal gold‑silver deposits. Geochemical modeling of boiling phenomenon suggests that boiling is effective for depositing gold, silver, copper, lead, and zinc and that it could form a bonanza zone enriched in gold and silver in the shallow zone above the lead and zinc-rich zone. Temperature, carbon dioxide content, salinity, and hydrogen sulfide content affect the deposited amount of metals, vertical extent, depth of mineralization, and gold/silver ratio of the ore zone, although other factors such as permeability, gangue mineralogy, duration of mineralization, kinetics of mineral precipitation, change in porosity, thermal conductivity, and fractures of host rocks could affect mineralization as well. Our modeling of boiling phenomenon demonstrates similar characteristics with natural low-sulfidation epithermal gold‑silver deposits, suggesting that boiling is an important mechanism to cause vertical metal zoning in the low-sulfidation epithermal gold‑silver deposits, even though mixing could also be important to precipitate metals in some deposits.

Research on Splash Lubrication Characteristics of a Spiral Bevel Gearbox Based on the MPS Method

In order to accurately and efficiently analyze the distribution law and motion status of lubricating oil in the spiral bevel gearbox of the electric multiple unit (EMU), a high-fidelity 3D CFD model of the spiral bevel gearbox of the EMU was established for the first time. The moving particle semi-implicit method was used to visualize the lubricating-oil flow field distribution characteristics of the gearbox. The distribution characteristics of lubricating oil in the gearbox with varying gear rotation speeds, initial lubricating-oil volume levels and oil temperatures were analyzed. It was found that the initial lubricating-oil volume is the factor with the largest influence, while the influences of gear rotation speed and oil temperature are relatively small. By analyzing the churning loss under various simulation conditions, it was found that the churning loss is positively correlated with the gear rotation speed and initial oil volume, and is more affected by the initial oil volume. The churning loss is negatively correlated with the oil temperature, and both are nonlinear relationships. The proportion of churning loss related to the driven gear is higher compared to that of the driving gear. These results can provide a theoretical basis for the subsequent optimization of the gearbox.

Poly(methyl methacrylate)/hyperbranched polysiloxane hybrid prepared by gamma‐radiation polymerization: Thermal stability, optical transparence, and UV shielding

AbstractIt is challenging to endow poly(methyl methacrylate) (PMMA) with good dielectric properties and UV absorption capacity while simultaneously overcoming its poor heat resistance. Herein, we report for the first time a novel organic–inorganic hybrid (PMMA‐HBPSi) derived from methyl methacrylate (MMA) and hyperbranched polysiloxane (HBPSi) fabricated via γ‐radiation curing. The typical properties (thermal stability, optical characteristics, and dielectric properties) of the hybrids were systematically investigated and discussed. The results demonstrated that the incorporation of HBPSi into the PMMA resin not only increased the thermal resistance, dimensional stability, and dielectric properties but also remarkably reduced the UV transmittance. Specifically, in comparison with pure PMMA, the initial degradation temperature (Tdi) of PMMA‐HBPSi increased by 31°C, with no phase transition occurred in a temperature range of 60–230°C, thus illustrating a significant improvement in the glass‐transition temperature. Moreover, the thermal expansion coefficient decreased by 86.9% at temperatures exceeding 118°C. The UV transmittance of PMMA was also found to decrease by 80% at 295 nm after the introduction of HBPSi. These attractive features of PMMA‐HBPSi demonstrate that the new approach proposed here is suitable for developing high‐performance organic glasses for optical, aviation, and electronic applications.

Исследование влияния морозного пучения на появление дефектов дорожных асфальтобетонных покрытий тепловизионным методом

The article presents the results of calculations for frost resistance according to the standard methodology and the methodology of ROSDORNII with their comparison, the results of a study of defects in road surfaces over time for frost heaving using a thermal imager. During the experiment, temperature profiles were compiled for the existing coating under the initial temperature conditions of St. Petersburg, and the results of a study of the occurrence of frost heaving were presented.

Oleaster (Elaeagnus Angustifolia L.) low-fibrous extract to powder: Drying kinetics analysis

Oleaster's emerging applications in the food and pharmaceutical industries are due to its anti-cancer and pain-relieving properties. Green extraction methods are crucial to ensure drug compatibility to eliminate unwanted substances. This study focuses on the single droplet drying method to simply mimic a spray dryer, investigating how the drying medium controls droplet evolution into particles. Experiments were conducted with low-fibrous oleaster extract at various initial solid concentrations and ambient temperatures (100 °C, 150 °C, and 200 °C). This paper also delves into the influence of temperature on droplet morphology evolution, impacting the final particle's characteristics. The droplet diameter exhibits intricate behavior, involving normal evaporation, abrupt shape, and size changes, and concluding in a sticky solid state. Moreover, the drying process duration extends with higher initial droplet concentrations. The findings recommend using 150 °C and 200 °C as favorable drying temperatures, resulting in raspberry-like particles at high temperatures and shedding light on the oleaster extract drying.

Cationic and anionic dyes adsorption from wastewater by clay-chitosan composite: An integrated experimental and modeling study

Water contamination with organic dyes is a significant environmental concern because it results in serious problems that threaten public health. In this study, a clay-based composite from Safi City, coated with chitosan (Cs), was used as an adsorbent (SRC/Cs) to remove co-existing dyes (methylene blue (MB) and congo red (CR)) from aqueous solution. Characterization methods such as Fourier infrared transform spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with EDX, and zero charge point determination were performed to understand the adsorption mechanisms of the co-pollutants in the adsorbent’s surface. The effects of pertinent parameters, such as initial dye concentration, adsorbent's dose, reaction time, pH, and temperature, were optimized to maximize the adsorption of both anionic and cationic dyes. The Langmuir, Freundlich, and Temkin isotherm models were applied to simulate experimental data. The DFT method was used to identify the key mechanism for MB and CR adsorption. It was found that the composite with 30% (w/w) CS and 70% (w/w) clay showed a complete removal of the target dye with an initial dye concentration of 20 mg/L at optimized pH 2 (CR) and pH 4 (MB), 60 min of reaction time, and 600 rpm of agitation speed. The Langmuir model was suitable for modeling the MB dye adsorption, while the Temkin isotherm was representative to describe CR adsorption. The adsorption capacities of both MB and CR dyes were 97.08 mg/g and 80.9 mg/g, respectively. The kinetic study showed that their adsorption process followed the pseudo-second-order. Thermodynamic parameters such as ΔH0, ΔG0, and ΔS0 imply that the adsorption reaction was spontaneous and endothermic. Overall, this study implies the potential of the composite as a novel adsorbent for removing MB and CR in single and binary systems.

Influence of Polar Modifiers on the Anionic Solution 1,3-Butadiene Polymerization

Abstract The present work addresses the critical technological challenge of producing butadiene-based synthetic rubbers with the required skid resistance through anionic polymerizations at positive temperatures. Here, the effects of adding different polar modifiers (bis[2-(N,N-dimethylamino)ethyl] ether, BDMAE; ditetrahydrofurylpropane, DTHFP; tetramethylethylenediamine, TMEDA; sodium stearate, SS; sodium palmitate, SP; sodium tert-amilate, ST) into the monomer feed in anionic solution polymerizations of 1,3-butadiene are investigated. Different feed concentrations and combinations of polar modifiers were tested in order to achieve high yields and vinyl contents with initial temperature of 40 °C. The reactions were evaluated according to the obtained temperature and pressure profiles and physico-chemical characterizations of the obtained polymer, with help of statistical analyses. The results clearly showed the positive effects of using polar modifiers in the feed. Particularly, the combination of BDMAE and sodium salts provided products with high vinyl contents (> 50 %mol) with high yields (> 80 wt%), leading to high temperature peaks (> 90 °C), as desired to enhance the skid resistance. Moreover, the performed statistical analyses and proposed mathematical modeling revealed the existence of multivariate and complex correlations among the analyzed process variables. The findings from this investigation can be pivotal for advancing industrial applications in the production of skid-resistant synthetic rubber.

Effect of Ti0.9Zr0.1Mn1.5V0.3 alloy catalyst on hydrogen storage kinetics and cycling stability of magnesium hydride

As a high-capacity hydrogen storage material, MgH2 still has the problem of high operating temperature and slow reaction kinetics. In this work, an TiMn2-based Laves phase alloy (Ti0.9Zr0.1Mn1.5V0.3, denoted as Ti–Mn) was first synthesized by arc melting and then employed to regulate the hydrogen storage properties of MgH2, with the carbon nanotubes (CNTs) as an aid agent to facilitate the hydrogen diffusion and heat transfer. It was shown that the introduction of Ti–Mn/CNTs can remarkably improve the hydrogen storage properties of MgH2. The MgH2 + 10 wt% Ti–Mn + 1 wt% CNTs composite has an initial dehydrogenation temperature of 195 °C and can absorb hydrogen at room temperature. As for the kinetics, it can release 6.1 wt% H2 in 5 min at 300 °C, and absorb 4.8 wt% H2 in 10 min at 150 °C. It still has a reversible capacity of 6.2 wt% after 100 cycles. Combination of Ti–Mn alloy and CNTs is more effective than Ti–Mn alloy or CNTs alone for regulating MgH2. Ti–Mn/CNTs does not alter the overall thermodynamics of MgH2. However, local destabilization of Mg–H bonds induced by the MgH2/Ti–Mn interfaces was observed experimentally and confirmed theoretically, which partially contributes to the enhanced hydrogen storage of MgH2. In addition, the active transition metals contained in the alloy was believed to accelerate the hydrogen dissociation and delivery during the hydrogen storage process. This work not only achieves the synergistic improvement of hydrogen storage of MgH2 by combination of Ti–Mn alloy and CNTs, but also presents the local destabilization mechanism to explain the improved hydrogen storage of MgH2 by Ti–Mn alloy experimentally and theoretically.