Search Results (833)

To advance a hydrogen-based energy society, the development of efficient hydrogen storage materials is essential. In particular, such materials are expected to be lightweight and chemically stable. Moreover, they must allow for easy storage and release of hydrogen. In this study, we theoretically designed hydrogen storage and release devices based on graphene (GR)—a lightweight and chemically stable material—using a direct ab initio molecular dynamics (AIMD) approach. The target reaction in this study is the hydrogen abstraction from hydrogenated graphene, H-(GR)-H, by hydrogen atom, resulting in molecular hydrogen formation: H-(GR)-H + H → GR-H + H₂. Hydrogen atom (H) can be readily generated through the discharge of H₂ gas. The calculated activation energy was −0.3 kcal/mol. The direct AIMD calculations showed that the hydrogen abstraction reaction proceeds without the activation barrier, and H₂ is easily formed by the collision of H atom with the H-(GR)-H surface. For comparison, the addition reaction of hydrogen atom to the graphene surface was investigated: GR + H → GR–H. The activation energies were calculated to be 5–7 kcal/mol. These energetic profiles indicate that both hydrogen storage and release proceed with low and negative activation energies, respectively. On the basis of these calculations, H₂-storage/release device was theoretically designed. Full article

Anti-apoptotic Bcl-2 family proteins (Bcl-2, Bcl-xL, and Mcl-1), are often overexpressed in cancer, which aids tumor growth and treatment resistance. As a result, these proteins are excellent candidates for novel anticancer drugs. Within this study a virtual library of betuline derivatives was built and screened for possible Bcl-2, Bcl-XL, and Mcl-1 inhibitors. For every target, molecular docking simulations were performed using two different engines (AutoDock Vina and Glide). The ligands that most frequently appeared among the top candidates were shortlisted after comparing the top-20 hits from both docking scoring functions. To assess binding stability, five of these promising compounds were chosen and run through 100 ns molecular dynamics (MD) simulations in complex with every target protein. Key persistent intermolecular contacts were identified from MD contact frequency histograms, and stability was evaluated using root-mean-square deviation (RMSD) profiles of protein–ligand complexes following equilibration. Additionally, Prime MM-GBSA binding energies (ΔG_bind) for the 15 docked complexes were computed, and ligand efficiency was reported. Two substances, BOxNaf1 and BT3, stood out among the screened derivatives as the most stable binders to all three Bcl-2 family targets according to the dual docking and MD analysis approach. When the MM-GBSA and RMSF/rGyr data are considered alongside docking and MD stability, BOxNaf1 and BOxPhCl1 emerge as the most compelling dual/multi-target candidates, whereas BT3, though MD stable, shows weaker MM-GBSA energetics and is retained as a lower-priority backup chemotype. Full article

Density functional theory calculations are performed to examine the reactivity of the coordinatively unsaturated (NH₃)₄RhO²⁺, (NH₃)₄CoO²⁺, and (NH₃)₄FeO⁺ species with methane and methanol. The ground low-spin state of rhodium oxide provides ideal energetics for the efficient and selective conversion of methane to methanol. The small activation energy barriers for all three steps (H₃C-H activation, CH₃-OH recombination, oxygen reload) promise fast conversion, while the larger activation barrier for the C-H activation of methanol provides the means to kinetically hinder further oxidation to the thermodynamically more favorable formaldehyde. The key finding was that rhodium prefers the 2 + 2 (as opposed to radical) activation mechanism of methane. To maintain the “ideal” electronic structure observed for (NH₃)₄RhO²⁺, we first replaced rhodium with its first-row lower cost counterpart cobalt. The cobalt complex favors a quartet state, which prefers a radical mechanism leading to the formation of methyl radical. This undesired effect vanishes, switching from Co⁴⁺ to Fe³⁺. Possible explanations for the observed trends are provided in terms of electronic structure features of the three metals. The production of methanol from methane has been a topic of intense interest over the past decades and we believe that this work offers new insights for tackling this challenging problem. Full article

Adverse climate events have recently highlighted an increasing need to deploy sustainable energetic infrastructures. The existing electric conversion circuits for solar energy provide high efficiency; however, gaps in sustainability and robustness can be identified by considering their operation during intense perturbations, potentially occurring for interplanetary energy transfer. Additionally, charging characteristics for energy storage units influence differently the operation life of battery arrays, with increased stability providing favorable operating conditions. Therefore, the present study develops an alternative controller for managing solar energy as well as a prototype for tracking the maximum power point, both constrained by robustness and renewability studies. For the presented design, stability analyses and simulations validated the management of electric energy from solar panels and the developed configuration resulted in improving current peak integral transient characteristics by using an alternative control method, demonstrating stability for an indefinite number of energy storage units. Furthermore, the estimation for VLSI (Very-Large-Scale Integration) of this constrained design has been concluded to potentially provide a solution with adequate performance, comparable to state-of-the-art computational circuits. However, certain limitations could arise when substituting the main computation parts with analyzed solutions and proceeding with integration-based manufacturing. Full article

Integrating phase change materials (PCMs) into building envelopes offers a powerful method for enhancing thermal mass and reducing heating, ventilation, and air conditioning energy demand. This study provides a comprehensive analysis of combining PCMs with various roof designs (flat, gable, and domed) and shading strategies in a Mediterranean climate to optimize residential building performance. Through a 3E (energetic, environmental, and economic) assessment and computational fluid dynamics (CFD) modeling, we determined that the use of PCM23 significantly enhances occupant comfort, improving the predicted mean vote by 17% and enhancing overall thermal comfort by 14%. The most effective configuration, a gable roof with integrated PCMs, outperformed a flat roof by reducing annual energy consumption by 20% (1103 kWh). This optimal design also yielded substantial economic and environmental benefits, including a 16.2 TD/m² reduction in annual energy costs, a short investment payback period, and a 4% decrease in operational CO₂ emissions. These results highlight the significant potential of pairing PCMs with passive architectural features to create more energy-efficient, cost-effective, and comfortable living environments. Full article

Incineration is a widely adopted method for the disposal of waste energetic materials (SP). Nevertheless, this approach is associated with considerable thermal energy loss and significant environmental pollution. To address these limitations, this study proposes a co-pyrolysis process incorporating pine sawdust (SD) with SP. This technique utilizes the exothermic decomposition of energetic substances and the endothermic pyrolysis of biomass. Through this synergistic thermal interaction, the process enables efficient energy recovery and facilitates the resource valorization of SP. The pyrolysis kinetics and thermodynamics of SP, SD, and their blends were investigated. Synchronous thermal analysis examined the co-pyrolysis reaction heat at varying blend ratios, while the temperature’s effects on the gas–liquid–solid product distribution were explored. The results indicate that the apparent activation energy (E_a) required for co-pyrolysis of the SP and SD exhibits an initial increase followed by a decrease in both Stage 1 and Stage 2. Furthermore, the mean apparent activation energy (E_avg) during Stage 1 (FWO: 101.87 kJ/mol; KAS: 94.02 kJ/mol) is lower than that in Stage 2 (FWO: 110.44 kJ/mol; KAS: 100.86 kJ/mol). Co-pyrolysis reaction heat calculations indicated that SD addition significantly mitigates the exothermic intensity, shifts decomposition to higher temperatures (the primary exothermic zone shifted from 180–245 °C to 265–400 °C), and moderates heat release. Elevated temperatures increase the gas yield (CO and H₂ are dominant). High temperatures promote aromatic bond cleavage and organic component release; the char’s calorific value correlates positively with the carbon content. Higher co-pyrolysis temperatures increase the nitrogenous compounds in the oil, while the aldehyde content peaks then declines. This work proposes a resource recovery pathway for SP, providing fundamental data for co-pyrolysis valorization or the development of catalytic conversion precursors. Full article

The current study experimentally investigates the performance of a novel pumpless Rankine cycle (PRC) configuration utilizing low-temperature heat sources. Precisely, a 1 kW_e PRC configuration using R245fa refrigerant is tested under different heat source and heat sink temperature levels. The energetic and exergetic performance indexes are calculated using validated simulation models developed in MATLAB incorporating the CoolProp library. The derived efficiency results are compared with the corresponding indexes of a conventional ORC system used as the baseline. The findings show that for a hot water heat source temperature of 90 °C and a cold water heat sink temperature of 10 °C as the working conditions, the time-averaged thermal efficiency maximizes at 4.5%, while the corresponding time-averaged exergy efficiency is calculated at 31%. Additionally, the innovative PRC topology shows higher efficiency rates compared to the conventional ORC solution for all the working scenarios tested. For a heat sink of 40 °C and a heat source of 90 °C, the thermal efficiency and the exergy efficiency calculated for the PRC are 7.7% and 7.5% higher, respectively, than the baseline ORC system, showing improved exploitation potential. Full article

Resonant acoustic technology utilizes low-frequency vertical harmonic vibrations to induce full-field mixing effects in processed materials, and it is regarded as a “disruptive technology in the field of energetic materials”. Although numerous scholars have investigated the mechanisms of resonant acoustic mixing, there remains a lack of parameter selection methods for improving product quality and production efficiency in engineering practice. To address this issue, this study employs phase-field modeling and fluid–structure coupling methods to numerically simulate the transport process of glycerol during resonant acoustic mixing. The research reveals the mass transfer mechanism within the flow field, establishes a liquid-phase distribution index for quantitatively characterizing mixing effectiveness, and clarifies the enhancement effect of fluid transport on solid particle mixing through particle tracking methods. Furthermore, parameter studies on vibration frequency and amplitude were conducted, yielding a critical curve for guiding parameter selection in engineering applications. The results demonstrate that Faraday instability first occurs at the fluid surface, generating Faraday waves that drive large-scale vortices for global mass transfer, followed by localized mixing through small-scale vortices. The transport process of glycerol during resonant acoustic mixing comprises three distinct stages: stable Faraday wave oscillation, rapid mass transfer during flow field destabilization, and localized mixing upon stabilization. Additionally, increasing either vibration frequency or amplitude effectively enhances both the rate and effectiveness of mass transfer. These findings offer theoretical guidance for optimizing process parameters in resonant acoustic mixing applications. Full article

The low water solubility of sulfamethazine (SMT) limits its clinical efficacy, making it crucial to study techniques such as cosolvency to optimize pharmaceutical formulations. This study aimed to thermodynamically evaluate the solubility of SMT in {acetonitrile (MeCN) + ethanol (EtOH)} cosolvent mixtures over a temperature range of 278.15 to 318.15 K in order to understand the molecular interactions that govern this process. SMT solubility in the mixtures was measured using a flask-shaking method. The solid phases were analyzed using differential scanning calorimetry (DSC) to rule out polymorphisms. Using the Gibbs–van’t Hoff–Krug model, we calculated the apparent thermodynamic functions of the solution and mixture from the obtained data. The results showed that solubility increased almost linearly with MeCN fraction and temperature, indicating that MeCN is a more efficient solvent and that the process is endothermic. Thermodynamic analysis revealed that dissolution is an endothermic process with favorable entropy for all compositions. The higher solubility in MeCN is attributed to the lower energetic cost required to form the solute cavity compared to the high energy needed to disrupt the hydrogen bond network of ethanol. This behavior can be explained by an enthalpy–entropy compensation phenomenon. This phenomenon provides an essential physicochemical basis for designing pharmaceutical processes. Full article

The development and implementation of scientifically substantiated solutions for the improvement and modernization of electromechanical devices, systems, and complexes, including electric drives, is an urgent theoretical and applied task for energetics, industry, transport, and other key areas, both in global and national contexts. The aim of this paper is to identify a rational model of an induction motor that balances computational simplicity and control system performance based on predictive approaches while ensuring maximum energy efficiency and reference tracking during the operation in dynamic modes. Five main mathematical models of an induction machine with different levels of detail have been selected. Three predictive control models have been implemented using GRAMPC (v 2.2), Matlab MPC Toolbox (v 24.1), and fmincon (R2024a) (from Matlab Optimization Toolbox). It has been established that in the dynamic mode of operation, the equivalent induction motor circuit with parameters $R_{fe} =const$, $L_{\mu }=f\left(I_{1d}\right)$, and $T_F=f\left({\omega }_{Rm}\right)$ is the most appropriate in terms of the following criteria: accuracy of control action generation, computation speed, and calculation of energy consumption. Full article

The hydroesterification of olefins provides a highly efficient way to produce high value-added ester products from simple and abundant olefin feedstocks. In this work, DFT calculation was performed to investigate the detailed reaction mechanism of propene hydroesterification over Rh(II)/Silicalite-2 catalysts. Three possible mechanistic pathways were systematically explored and compared in terms of their adsorption configurations, reaction energies, and transition-state barriers. Among them, the Carbonylation-First pathway exhibited the most favorable energy profile with the lowest overall kinetic barriers, indicating it to be the most likely way for ester formation. A comparison of methyl butyrate and methyl isobutyrate formation revealed that the linear product is energetically more favorable, particularly along the Carbonylation-First pathway. Moreover, the Rh(II) center demonstrates a different catalytic effect over conventional Rh(I) species by significantly lowering the energy barrier for CO insertion, a key step in both hydroformylation and hydroesterification. These findings provide fundamental insight into the role of Rh(II)/zeolite systems in carbonylation reactions and offer theoretical guidance for the design of catalysts. Full article

The paper investigates the potential of co-electrolysis as a viable pathway for hydrogen production and industrial decarbonization, expanding on previous studies on water electrolysis. The analysis adopts a general and critical perspective, aiming to assess the realistic scope of this technology with regard to current energy and environmental needs. Although co-electrolysis theoretically offers improved efficiency by simultaneously converting H₂O and CO₂ into syngas, the practical advantages are difficult to consolidate. The study highlights that the energetic margins of the process remain relatively narrow and that several key aspects, including system irreversibility and the limited availability of CO₂ in many contexts, significantly constrain its applicability. Despite the growing interest and promising technological developments, co-electrolysis still faces substantial challenges before it can be implemented on a larger scale. The findings suggest that its success will depend on targeted integration strategies, advanced thermal management, and favorable boundary conditions rather than on the intrinsic efficiency of the process alone. However, there are specific sectors where assessing the implementation potential of co-electrolysis could be of interest, a perspective this paper aims to explore. Full article

This study resolves the long-standing question of the origin of bilinear Low Cycle Fatigue (LCF) behavior in Ti-6Al-4V using a high-fidelity CPFEM-XFEM framework. We identify that the fundamental origin lies in a fundamental shift in the efficiency of converting macroscopic energy dissipation into microscopic damage. This energetic efficiency is directly governed by the evolution of plastic strain heterogeneity (quantified by the Coefficient of Variation, CV). At low strain amplitudes, high strain localization (high CV) creates a highly efficient “energy funnel,” concentrating dissipated energy into a few critical grains. This manifests physically as a single-crack failure mode, where the crack initiation phase is prolonged, consuming ~80% of the total fatigue life. Conversely, at high strain amplitudes, deformation homogenization (low CV) leads to inefficient, diffuse energy dissipation across many grains. The material must therefore activate a more drastic failure mechanism—multi-site crack initiation and coalescence—to accumulate sufficient damage, reducing the initiation phase to just ~45% of the total life. Therefore, the bilinear C-M curve is the macroscopic signature of this transition from an energetically efficient, localized damage mode to an inefficient, distributed one. This work provides a quantitative, mechanism-based framework for understanding and predicting the complex fatigue behavior of advanced metallic materials. Full article

Aluminum powder has the advantages of high calorific value, high density and convenient source, and is a commonly used metal fuel in the explosives and propellants industry. Nanometer aluminum powder (nAl) has higher reactivity and higher reaction completeness than micron aluminum powder (μAl), which can improve the energy performance of mixed explosives and the burning rate of propellant. However, nAl has some disadvantages, such as easy oxidation and deterioration of the preparation process, which seriously affect its application efficiency. In order to improve these shortcomings, suitable surface coating treatment is needed. The effects of surface coating on the characteristics of nAl and on the energy and safety of explosives are summarized in this paper. The results show that surface coating of nAl can not only improve the compatibility between nAl and energetic materials, reduce the hygroscopicity of energetic composites, mitigate the easy oxidation of nAl, and protect the preparation process, but also improve the energy performance of explosives and the burning rate of propellant, increase the reaction characteristics of energetic mixtures, and reduce the mechanical sensitivity of those mixtures. In addition, the surface coating modification of nAl can obviously reduce the agglomeration of condensed-phase combustion products, thus reducing the loss of propulsion efficiency caused by agglomeration. This study is expected to provide reference for the surface coating of nAl and its application in explosives. Full article

This study aimed to determine the net energy (NE) values of common energy-supplying nutrients, including starch, protein, and fat, to investigate their influence on energetic efficiency and NE partition patterns in growing pigs, and to develop prediction equations for the protein deposition (PD) and lipid deposition (LD) based on nutrient characteristics of ingredients. Two experiments were conducted. In Experiment 1, 36 growing barrows (Duroc × Landrace × Yorkshire, initial body weight = 28.1 ± 0.8 kg) were randomly allotted to six treatments, with six replicated pigs per treatment. The diets were formulated as follows: a corn–soybean meal basal diet (T1), and five experimental diets containing of 27% corn starch (T2), 27% tapioca starch (T3), 27% pea starch (T4), 5% soybean oil (T5), and 11.8% casein (T6), respectively. In Experiment 2, PD and LD data of 47 ingredients were collected. Subsequently, the nutrient characteristics of ingredients were used as input variables, and PD and LD were used as output variables to establish the prediction equations. Results exhibited that pigs fed the T2, T3, and T4 diets showed increased digestibility of gross energy (GE) and organic matter (OM) compared to those fed the T1 diet (p < 0.01). For various kind of starches, a greater efficiency of using metabolizable energy (ME) for net energy not deposited as protein (PD-free NE, efficiency denoted as kj) was observed when pigs were fed the T2 or T3 diets compared to the T4 diet. Moreover, the kj of soybean oil was 11% and 27% greater than that of starch and casein, respectively, while casein demonstrated 46% and 39% greater efficiency of using ME for PD (efficiency denoted as pj) compared to starch and soybean oil, respectively. Finally, the best-fitted prediction equations for PD and LD were PD = 364.36 − 18.44 × GE + 29.10 × CP − 3.79 × EE − 21.37 × ADF (R² = 0.96; RMSE = 105.15) and LD = −1503.50 + 21.58 × CP + 51.98 × EE + 26.30 × Starch + 26.81 × NDF − 23.87 × ADF (R² = 0.98; RMSE = 172.85), respectively. In summary, there are considerable differences in energetic efficiency and NE partition patterns among various nutrients. In addition, PD and LD can be predicted through nutrient characteristics of ingredients, presenting an innovative approach and methodological framework for the precision nutrition of pigs. Full article