Search Results (1,890)

Polypropylene (PP) dielectric capacitors are crucial for electronics and electric power systems due to their high power density. However, their relatively low energy density limits their practical application in energy storage devices, presenting a long-standing challenge. Montmorillonite (MMT), a natural phyllosilicate mineral abundantly found on earth, features a two-dimensional nanosheet structure and excellent insulating properties. MMT nanosheets have shown promise in enhancing the breakdown strength and energy storage capability of PP dielectric, but compatibility issues with the PP matrix remain a challenge. In this study, we propose a novel surface modification strategy in which polystyrene (PS)-capped MMT (PCM) nanosheets are synthesized through a polymerization–dissolution process. The modified PCM nanosheets demonstrate improved compatibility and are well dispersed within the PP matrix. Optimal loading of the PCM nanosheets effectively dissipate charge energy and hinder the growth of electric trees in the PP matrix. As a result, the PP nanocomposite with 0.2 wt% PCM nanosheets exhibits an enhanced breakdown strength of 619 MV m⁻¹ and a discharged energy density of 4.23 J cm⁻³, with an energy storage efficiency exceeding 90%. These findings provide a promising strategy for the development of high-energy-density dielectric capacitors in an economical manner. Full article

The low thermal conductivity of phase change material (PCM) critically constrains the cooling performance of PCM-based battery thermal management system (BTMS). To address this limitation, embedding high-thermal-conductivity fins into PCM was recently explored. However, it may increase the overall BTMS mass, degrading vehicle performance. Therefore, a quantitative evaluation of the effects of fin design on cooling performance and system mass is required. In this study, the effects of fin design factors in a PCM–fin structured BTMS on the maximum cell temperature and BTMS mass was analyzed using design of experiments (DoE) and analysis of variance (ANOVA). To characterize BTMS thermal behavior, a numerical model was developed by applying thermal fluid partial differential equations (PDEs) with the enthalpy–porosity method to represent the phase change of the PCM. Fin number, thickness, and angle were selected as design factors; responses were calculated through thermal fluid analysis. The results showed a trade-off between thermal performance and mass across all design factors. The number of fins had the greatest effect on maximum cell temperature (78.27%) but less on mass (28.85%). Fin thickness moderately affected temperature (16.71%) but strongly increased mass (63.93%). Fin angle had minimal impact, 4.10% on temperature and 3.10% on mass. Full article

The significant energy consumption and contribution to greenhouse gas emissions by the construction sector need careful attention to explore innovative sustainable solutions for improving the energy efficiency and thermal comfort of building envelopes. The integration of phase-change materials (PCMs) into building commodities is a favorable technology for minimizing energy consumption and enhancing thermal performance. This review paper covers the impact of PCM incorporation into construction materials, such as walls, roofs, and glazing units. Additionally, it examines different embedding techniques like direct incorporation, immersion, macro and micro-encapsulation, and form and shape-stable PCM. Factors affecting the thermal performance of PCM-integrated buildings, including melting temperature, thickness, position, volumetric change, vapor pressure, density, optical properties, latent heat, thermal conductivity, chemical stability, and climate conditions, are elaborated. Furthermore, the latest experimental and numerical simulations, as well as modeling techniques, evident from case studies, are investigated. Ultimately, the advantages of PCM integration, including energy savings, peak load reduction, improvement in interior comfort, and reduced heating, ventilation, and air-conditioning dependence, are explained alongside the limitations. Finally, the recent progress and future potential of PCM-integrated construction materials are discussed, focusing on innovations in this field, addressing the status of policies in line with the United Nations Sustainable Development Goals, and outlining research potential for the future. Full article

:Solvents represent the quiet majority in biomolecular systems, yet modeling their influence with both speed and ri:gor remains a central challenge. This study maps the state of the art in implicit solvent theory and practice, spanning classical continuum electrostatics (PB/GB; DelPhi, APBS), modern nonpolar and cavity/dispersion treatments, and quantum–continuum models (PCM, COSMO/COSMO-RS, SMx/SMD). We highlight where these methods excel and where they falter, namely, around ion specificity, heterogeneous interfaces, entropic effects, and parameter sensitivity. We then spotlight two fast-moving frontiers that raise both accuracy and throughput: machine learning-augmented approaches that serve as PB-accurate surrogates, learn solvent-averaged potentials for MD, or supply residual corrections to GB/PB baselines, and quantum-centric workflows that couple continuum solvation methods, such as IEF-PCM, to sampling on real quantum hardware, pointing toward realistic solution-phase electronic structures at emerging scales. Applications across protein–ligand binding, nucleic acids, and intrinsically disordered proteins illustrate how implicit models enable rapid hypothesis testing, large design sweeps, and long-time sampling. Our perspective argues for hybridization as a best practice, meaning continuum cores refined by improved physics, such as multipolar water, ML correctors with uncertainty quantification and active learning, and quantum–continuum modules for chemically demanding steps. Full article

This study evaluates the energy performance and efficiency of a low-concentration photovoltaic (CPV) system integrated with a phase change material (PCM), referred to as the CPV–PCM system, which stores and delivers thermal energy for building applications. A paraffin-based PCM with a melting point range of 58–60 °C was selected to align with typical building temperature requirements. The system was tested over three consecutive days in July at Al Ain, United Arab Emirates, under extreme climatic conditions (2100 W/m² solar irradiance, 35–45 °C ambient temperature), and its performance was compared to standard CPV and traditional tracked PV systems. The results demonstrate that PCM integration significantly enhances thermal regulation, reducing CPV peak temperatures by 38 °C (from 123 °C to 85 °C) and average temperatures by 22 °C (from 88 °C to 66 °C). The CPV–PCM system achieved a total energy efficiency of 60%, doubling that of standard CPV (30%) and tracked PV (25%), with cumulative electrical and thermal energy outputs of 370 Wh and 290 Wh, respectively. This dual electrical–thermal output enables the system to meet building heating demands, such as ~200–300 Wh/m² for domestic hot water and ~100–150 Wh/m² for space heating in United Arab Emirates winters, positioning it as a sustainable solution for energy-efficient buildings in arid regions. The findings underscore the advantages of PCM-based thermal control in CPV systems for hot climates, addressing gaps in prior studies focused on moderate conditions. Future research should explore long-term durability, optimized containment techniques, and alternative PCMs to further improve performance. Full article

In low-light optical imaging, the scarcity of incident photons and the inherent limitations of imaging sensors lead to challenges such as low signal-to-noise ratio, limited dynamic range, and degraded contrast, severely compromising image quality and optical information integrity. To address these challenges, we propose a novel low-light image enhancement technique, LightenResDiff, which combines a residual diffusion model with the discrete wavelet transform. The core innovation of LightenResDiff lies in it accurately restoring the low-frequency components of an image through the residual diffusion model, effectively capturing and reconstructing its fundamental structure, contours, and global features. Additionally, the dual cross-coefficients recovery module (DCRM) is designed to process high-frequency components, enhancing fine details and local contrast. Moreover, the perturbation compensation module (PCM) mitigates noise sources specific to low-light optical environments, such as dark current noise and readout noise, significantly improving overall image fidelity. Experimental results across four widely-used benchmark datasets demonstrate that LightenResDiff outperforms existing methods both qualitatively and quantitatively, surpassing the current state-of-the-art techniques. Full article

Consistency indices quantify the degree of transitivity and proportionality violations in a pairwise comparison matrix (PCM), forming a cornerstone of the Analytic Hierarchy Process (AHP) and Analytic Network Process (ANP). Several methods have been proposed to compute consistency, including those based on the maximum eigenvalue, dot product, Jaccard index, and the Bose index. However, these methods often overlook two critical aspects: (i) vector projection or directional alignment, and (ii) the weight or importance of individual elements within a pointwise evaluative structure. The first limitation is particularly impactful. Adjustments made during the consistency improvement process affect the final priority vector disproportionately when heavily weighted elements are involved. Although consistency may improve numerically through such adjustments, the resulting priority vector can deviate significantly, especially when the true vector is known. This indicates that approaches neglecting projection and weighting considerations may yield internally consistent yet externally incompatible vectors, thereby compromising the validity of the analysis. This study builds on the idea that consistency and compatibility are intrinsically related; they are two sides of the same coin and should be considered complementary. To address these limitations, it introduces a novel metric, the Consistency Index G (CI-G) based on the compatibility index G. This measure evaluates how well the columns of a PCM align with its principal eigenvector, using CI-G as a diagnostic component. The proposed approach not only refines consistency measurement but also enhances the accuracy and reliability of derived priorities. Full article

The one-step method in reactor physics has become one of the important research directions in recent two decades. Based on the open-source OpenMOC code, the following work was carried out. Firstly, the global–local resonance method with multi-group and continuous neutron libraries was researched and established. Next, based on the 2D and 3D MOC solver, the 2D/1D and the MOC/DD transport methods were realized in OpenMOC. Finally, verification of the transport and resonance methods was conducted using the C5G7 macro benchmark and the VERA micro benchmark. The numerical results demonstrated that the average eigenvalue deviation was 44 pcm and average maximum pin power distribution deviation was 0.37% in the VERA-2 benchmark, which showed the good accuracy of the resonance method. As for the transport method, the 3DMOC method exhibited better accuracy in strong anisotropic cases, but the computational time was 38 times that of the 2D/1D method. Full article

Low thermal conductivity of phase change materials (PCMs) remains a major limitation in the design of efficient thermal energy storage systems. Enhancing the thermal performance of PCM storage units is therefore a critical design consideration. Fin geometry plays a pivotal role in improving the heat charging and discharging rates by influencing heat transfer mechanisms, particularly natural convection during melting. This study presents a two-dimensional numerical investigation of novel fin geometries aimed at accelerating the melting process of PCM in a double-pipe heat exchanger. Four fin designs are examined: single-step thickness reduction, double-step thickness reduction, stepwise thickness reduction/expansion, and smooth thickness reduction fins. These configurations are specifically developed to promote natural convection currents in the molten PCM regions adjacent to the fin’s surfaces. The enthalpy–porosity method is employed using ANSYS Fluent 19 to simulate the phase change process. The COUPLED algorithm is used for pressure–velocity coupling, with the PRESTO! scheme applied for pressure interpolation and a second-order upwind scheme adopted for the discretization of transport equations. The results demonstrate that the proposed thickness reduction fins significantly enhance the PCM melting rate by intensifying natural convection currents, driven by localized temperature gradients along the fin surfaces. Full article

Solid–liquid phase change materials (PCMs) have attracted significant attention due to their high enthalpy, which enables superior energy storage density. However, it is difficult to maintain their original shapes in a molten state. Therefore, confining PCMs within porous materials is an important method, either through mixing molten polymers and PCMs or confining PCMs in pre-prepared porous materials (e.g., aerogels). The former method is straightforward and easy to execute but its stability is severely limited, and the latter is exactly the opposite. Herein, aerogel-confined functional liquid made via in situ solid–liquid host–guest composite strategy is reported. As a proof of concept, Nylon 66 and 1,6-hexanediol are selected as the solid and liquid phases, respectively. 1,6-hexanediol not only serves as a solvent to dissolve Nylon 66 but also induces sol–gel transition during the cooling process and acts as a PCM to store energy. Unlike aerogel-supported systems requiring multi-step processing, this approach integrates porous host formation and PCM encapsulation in one step. The resulting shape-stabilized PCMs (ss-PCMs) exhibit obscure leakage, high latent heat (160 J/g), mechanical robustness (compressive modulus of 3.6 MPa), and low thermal conductivity (0.081 W/(m·K)) above 75 wt% loading of 1,6-hexanediol. These ss-PCMs enable infrared stealth by delaying thermal detection and passive thermal buffering that suppress temperature fluctuations. The in situ solid–liquid host–guest composite strategy is straightforward, being achievable through a one-pot method involving heating and cooling cycles, with high raw material utilization and minimal waste generation, thus maximizing the conversion rate of raw materials into the final product. By combining the excellent liquid retention capability of aerogels with process simplicity, this methodology opens new avenues for the development of ss-PCMs. Full article

Solid–liquid phase change materials (PCMs), promising for thermal management, face limited application due to leakage and low thermal conductivity. In this work, a shape-stabilized composite PCM was fabricated using a one-pot in situ process by mixing polyethylene glycol (PEG) with the novel metal–organic network called CFK, which was synthesized from carboxylated multi-walled carbon nanotubes (CMWCNTs), FeCl₃, and Kevlar nanofibers (KNFs). The morphology, composition, and thermophysical characteristics of the composite PCM were assessed. Key properties analyzed to validate its performance included leakage rate, thermal conductivity, latent heat, light absorption, photothermal conversion efficiency, and cycling stability. This composite PCM exhibits reduced leakage while maintaining remarkable thermal energy charge/discharge performance. The study establishes that the composite PCM containing 89.9 wt% PEG has a leakage rate of 0.76% since the PEG molecules are deeply embedded in the pores of CFK. The thermal conductivity of this composite PCM was enhanced by 170.5% relative to pure PEG, and the latent heat was measured as 147.9 J·g⁻¹ for fusion and 143.7 J·g⁻¹ for crystallization. Additionally, this composite PCM reveals excellent light absorption capacity, a photothermal conversion efficiency as high as 83.4%, and outstanding stability in photothermal cycling experiments. In short, this work offers a new strategy for both preparing high-performance composite PCMs and applying them in visible light conversion. Full article

An electron optic system (EOS) consisting of a sheet electron beam gun (SEB) and a pole offset periodic cusped magnet (PO-PCM) is reported for 340-GHz frequency. A sheet electron beam with a voltage of 29 kV, beam compression ratio of 16, and a beam waist of size 0.17 mm × 0.044 mm was designed and optimized using computer simulation technology (CST). The EOS was capable of transmitting the beam with a current of 6.9 mA through a beam tunnel of size 0.516 mm × 0.091 mm, having a length of 60 mm with the help of a pole offset periodic cusped magnet. The axial magnetic field generated by the PCM was 0.32 T. The EOS was efficient enough to transmit the beam stably through the beam tunnel with a transmission rate of 100%. Full article

This article systematically reviews biopolymer phase change materials (PCMs) for TES applications. The review was conducted based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using databases from Scopus, Web of Science, and Google Scholar. The biopolymer PCMs are categorized as natural, synthetic, and hybrid (a combination of natural and synthetic). A total of 82 articles were included in the analysis. Several thermal properties, mechanical properties, advancements, and challenges are discussed. This article aims to review biopolymer PCMs and identify research gaps for future development. Natural biopolymer PCMs include lipid, lignin, polysaccharides, proteins, etc. Synthetic biopolymer PCMs include supramolecular, polyethylene glycol, polyurethane, polyrotaxane, polylactic acid, etc. Hybrid biopolymer PCMs combine natural and synthetic polymers with conductive fillers, balancing high latent heat with improved thermal stability and durability, although issues, like leakage and low conductivity, persist. It is found that biopolymers can be used as the core and supporting matrix of PCMs. Several cases and configurations of core, supporting matrix, and fillers in the development of PCM from biopolymers are discussed. This article also demonstrates that several natural, synthetic, and hybrid biopolymer PCMs hold promise for demanding TES applications due to their tunable properties and reliability. Biopolymer PCMs offer a sustainable alternative to petroleum-derived substances by minimizing environmental harm, cutting carbon emissions, and promoting a circular economy. This review also highlights several challenges, such as feedstock selection, purification and encapsulation, system compatibility, and standardization, that future research might address to enable scalable, safe, and cost-effective biopolymer PCM solutions. Full article

Glucosamine (GlcN) is a high-value compound with significant health applications. GlcN is widely used in the food and health industry as a food additive or functional food. The development of a green, efficient, and safe method for GlcN production is of great significance due to the complexity of traditional production methods, environmental pollution, and sensitization of raw materials. In this study, Saccharomyces cerevisiae genes PFK1, PDB1, GNA1, ISR1, and PCM1 were knocked out using the Clustered Regularly Interspaced Short Palindromic Repeats Cas9 (CRISPR-Cas9) method. In addition, three key enzyme genes, glucosamine-6-phosphate deaminase GlmD, glucosamine-6-phosphate phosphatase GlmP, and ammonium transporter AMT1, were introduced to construct engineered strains for GlcN synthesis in the presence of high-concentration inorganic ammonium ions. The results indicated that S. cerevisiae HPG5 with GlmD, GlmP, and AMT1 integration and simultaneous deletion of PFK1, PDB1, GNA1, PCM1, and ISR1 achieved the highest GlcN yield (1.95 ± 0.02 g/L) during fermentation with 10 g/L (NH₄)₂SO₄, which was 2.47-fold higher than the control. The conversion rate of glucose to GlcN in HPG5 was 9.75% in liquid YPD medium containing 20 g/L of glucose and 10 g/L of (NH₄)₂SO₄. Thus, the results indicated that S. cerevisiae HPG5 could effectively produce GlcN in the presence of high-concentration ammonium sulphate. This study provides a promising alternative, S. cerevisiae HPG5, for GlcN production. Full article

Background/Objectives: It is unclear whether enamel margins should be beveled in direct resin-based restorations. This study evaluated the influence of enamel beveling on the marginal quality of mesio-occluso-distal (mod) cavity boxes. Methods: Seventy-five caries-free human molars were divided into three groups. Mod-cavities with the entire margin in the enamel were prepared ± proximal bevel (n = 25). Twenty-five beveled mod-cavities served as control. Each group was restored with five material combinations: micro hybrid composite with etch-and-rinse (ER) or self-etch (SE) adhesive, compomer with ER or SE, and low-shrinkage composite with ER. A complex filling technique was used in the control. After artificial aging (1000 thermal cycles, 5/55 °C), the percentage of continuous margins (PCM) of the proximal boxes was analyzed by scanning electron microscopy using epoxy replicas (×300), and the marginal seal was assessed by light microscopy after dye penetration (×64). Statistical analysis was performed using Kruskal–Wallis and Mann–Whitney U tests (p < 0.05). Results: No significant differences in PCM were found between the restorative systems (p = 0.075). The composite with low shrinkage showed the highest mean PCM of all groups (78.1%). Significant differences in marginal seal were observed between the restoratives after bevel preparation (p < 0.05). Beveling significantly improved the PCM only for the hybrid composite (p < 0.05), whereby the effect on marginal seal was less pronounced. Conclusions: Clinicians should be aware that beveling mod-cavities does not necessarily improve the marginal quality of direct resin-based restorations bonded with well-established adhesives and may be more beneficial for traditional hybrid composites. Full article