• Transient energy balance model for a PCM coupled single slope solar still (Agadir climate). • Combined influence of basin water (10–30 kg) and PCM mass (8–30 kg) analyzed for four PCMs. • Higher water mass reduces yield; whereas higher PCM mass enhances nocturnal production. • The highest nocturnal yield (∼0.5787 kg. m⁻². night⁻¹) was achieved with 30 kg of STSPH. Solar distillation using solar stills offers a sustainable route for seawater desalination in arid and semi-arid regions affected by freshwater scarcity. This study presents a comparative numerical assessment of a single slope solar still integrated with phase change materials to enhance thermal storage and distillate production. A transient model based on energy balance equations for the main components was developed and solved, and the predictions were validated against published experimental and theoretical results. Simulations were carried out for a representative partly cloudy day in Agadir, Morocco, to examine the combined influence of basin water thickness and PCM mass. Four PCMs were investigated: paraffin wax, stearic acid, sodium thiosulfate pentahydrate (STSPH), and paraffin RT27. The results show that PCM integration enhances nocturnal productivity by releasing stored latent heat after sunset; for paraffin wax, stearic acid, and STSPH, overnight yield increased with PCM mass, confirming the role of storage capacity, while increasing water thickness reduced the thermal response of the still due to higher thermal inertia, delaying temperature rise and distillate generation. Among the tested materials, stearic acid at 8 kg achieved the highest cumulative daily yield of 5.35 kg.m⁻².day⁻¹, outperforming paraffin wax, STSPH, and paraffin RT27 at the same mass. While, STSPH at 30 kg provides the highest nocturnal yield, reaching 0.5787 kg.m⁻².night⁻¹, higher than the conventional solar still by approximately 399.3%. The energy efficiency ranged from 39.17% to 46.59%, with the highest performance obtained using 8 kg of stearic acid and the lowest recorded for 18 kg of RT27.

Experimental investigation of solar desalination systems using low-cost thermal energy storage from waste glass micromaterials in paraffin wax

Thermo-fluid and structural optimization of hybrid air-assisted CPCM battery thermal management for electric vehicles

Influence of varying aspect ratios and flow rates in thermal energy storage tanks using phase change material

CsPbBr3 perovskite semiconductors have emerged as a leading candidate for next-generation radiation detectors because of their exceptional charge transport properties, defect tolerance, and record-breaking sensitivity and energy resolution. Their long-term stability, however, is hindered by electrode-driven electrochemical decomposition, which is accelerated by moisture- and oxygen-assisted ion migration during operation. Here, we investigated organic and inorganic encapsulation strategies as both environmental barriers and means to suppress interfacial degradation pathways. Atomic layer deposition of Al2O3 provided a conformal passivation layer that blocked environmental ingress, suppressed ionic diffusion, reduced leakage current, enhanced energy resolution, and expanded the operational electric-field window beyond 5 kV cm-1. By contrast, organic encapsulants such as paraffin wax and polystyrene slowed moisture diffusion but did not suppress interfacial reactions, with wax extending stability to over 90 days. These results show that ALD-Al2O3 suppresses dominant interfacial degradation pathways, enabling stable, high-field operation and advancing the practical deployment of CsPbBr3 gamma-ray detectors.

Dehydrogenation reactions are thermodynamically constrained by their inherent endothermic nature. The concomitant thermodynamic barriers can be overcome via photochemical strategies that harness light to activate intrinsically strong C═O, C─H, and O─H bonds. This review surveys recent progress and challenges in acceptorless light-driven dehydrogenation reactions, focusing on dehydrogenation of linear sp3-hybridized bonds, dehydrogenative coupling reactions, dehydrogenative cyclizations, and dehydrogenation of cyclic hydrocarbons. We identified distinct trends in the catalysts used for light-driven dehydrogenations, including homogeneous unary photocatalysts in which a single molecule absorbs light and catalyzes both oxidation and hydrogen evolution, cooperative homogeneous systems in which two separate catalysts fulfill these roles, as well as heterogeneous systems including nanostructured semiconductors and hybrid materials. In particular, this work uniquely synthesizes mechanistic knowledge across these classes and introduces a unifying classification framework that clarifies how distinct photochemical mechanisms achieve bond activation and hydrogen evolution without external acceptors. First, homogeneous unary photoactive Rh(I) catalysts promote dehydrogenation of both linear and cyclic sp3-hybridized C-C bonds in hydrocarbon substrates via oxidative C-H addition with subsequent β-hydride elimination. Second, binary homogeneous photocatalytic systems, consisting of a photosensitizer and a transition-metal-based proton reduction catalyst, enable all four types of dehydrogenation reactions via SET. Third, heterogeneous catalysts employed in light-driven dehydrogenation reactions often comprise a semiconductive support material integrated with a transition-metal-based active site, functioning via Mott-Schottky type photoinduced charge separation.

Phenanthridines are a key N-heterocyclic scaffold that is widely found in numerous important functional compounds. Herein, we disclose an aryldiazonium salt-mediated radical alkylation/cyclization reaction of N-arylacrylamides with diverse C(sp3)-H partners including acetonitrile, acetone, alcohols, chlorides, cyclic alkanes, and toluene derivatives. Numerous alkylated phenanthridines are prepared with up to 77% yield without oxidants or transition-metal catalysts, showing good group tolerance. Preliminary mechanistic studies reveal that the generation of alkyl radicals proceeds through hydrogen atom transfer (HAT) between C(sp3)-H bonds and aryl radicals, which are generated in situ from aryldiazonium salts.

We investigated collision processes of droplets of paraffin wax melt with a water surface. We found that when the water temperature is significantly lower than the melting temperature of the wax, a liquid droplet solidifies in the vicinity of the interface between the wax and water, and the solidified wax left on the water surface after collision exhibits diverse morphologies, including irregularly breaking films and petal-like films. Experimental results and rheological measurements indicate that at large falling distances and relatively high water temperatures, the wax deforms as a plastic fluid and expands in the form of a hemispherical sheet along with the water surface, forming a cavity. Under such conditions, a thin solidified film created at the interface gives an effective interfacial tension to the interface and suppresses its expansion. We derived the time evolution equations of the size and the thickness of a solidified film. These equations indicate that the effective interfacial tension is approximately determined by the film thickness and the yield stress of the wax.

Solar-thermal-electrical generators offer a promising route for the conversion of solar energy into electricity. Their reliability can be enhanced by integrating phase change materials (PCMs) to buffer thermal fluctuations and ensure stable operation, yet conventional PCMs often suffer from low thermal conductivity and poor solar capture. Herein, photosensitive Co/C-anchored reduced graphene oxide (rGO) conductive framework was fabricated via metal-organic framework (MOF) pyrolysis-assisted zinc volatilization strategy. This design enables the in situ formation of MOF-derived uniformly dispersed cobalt nanoparticles within rGO framework. After the encapsulation of paraffin wax (PW), the resultant rGO@Co/C-PW composite PCMs demonstrate a remarkable solar-thermal conversion efficiency of 92.5% under 100 mW·cm-2 irradiation, attributed to the synergistic interplay between the broadband absorption and non-radiative relaxation of graphitic carbon and the localized surface plasmon resonance of Co nanoparticles. rGO@Co/C-PW also exhibits enhanced thermal conductivity, high phase change enthalpy, and excellent long-term cycling stability, supported by regulated non-isothermal phase transition kinetics via heterogeneous nucleation and spatial confinement. When integrated into a thermoelectric module, a sustained and stable power output of 8.82mW under 100mW·cm-2 is generated, capable of powering small electronic devices. This study provides valuable insights into developing next-generation PCMs integrating solar-thermal conversion, thermal energy storage, and thermoelectric output.

Carbocation rearrangement is a powerful tool for converting a simple precursor into a complex molecular scaffold. However, controlling the stereoselectivity of a reaction that involves carbocation rearrangement is challenging and remains elusive. In this study, we demonstrate a novel iridium-catalyzed Wagner-Meerwein rearrangement and asymmetric hydrogenation of carbocation precursors (1-(aryl)-1-(1-methylcyclobutyl/cyclopentyl) ethan-1-ol) for the synthesis of various optically active gem-dimethyl cycloalkanes. Hence, enantiopure gem-dimethyl-containing compounds are important motifs found in many natural products, and some are FDA-approved drugs. Our methodology starts with an iridium-catalyzed formal deoxygenation of tertiary alcohols to generate a tertiary carbocation that triggers the Wagner-Meerwein rearrangement via the ring expansion and alkyl migration cascade to furnish a stable tertiary-benzyl carbocation. Sequential olefination and in situ asymmetric hydrogenation provide access to various gem-dimethyl chiral cycloalkanes in excellent yield (> 99%) and enantioselectivity (ee up to > 99%). Otherwise, establishing a high yield and enantioselectivity in a saturated cyclic hydrocarbon next to a sterically hindered gem-dimethyl group would not be possible by conventional methods.

ABSTRACT Recent interest in the use of nano‐enhanced phase change materials (Ne‐PCMs) for thermal energy storage (TES) has increased due to their improved thermophysical properties. A promising method to enhance their thermal conductivity is to incorporate an innovative fin geometry that accelerates melting (MP). Here, we study the thermal performance of six varieties of fins in a latent heat storage unit filled with copper nanoparticle‐enhanced paraffin wax. Three configurations use T‐shaped fins, while the other three incorporate fins tilted at 45°. The melting front and heat transfer (HT) were simulated using a numerical code that solved the enthalpy‐porosity approach. We focus on the evolution of mean temperature, liquid fraction, Bejan (Be) number, and stored thermal energy. Among all configurations, Case 3, which used optimal T‐fins, exhibited the fastest thermal response, with a total melting time reduced by 31.91% compared to the reference design (Case 1). Furthermore, the inclined fins in Cases 4, 5, and 6 were found to delay the MP, increasing the required time by 91.7%, 80%, and 56.25%, respectively, relative to their non‐tilted counterparts. These results highlight the superior performance of Case 3, which is recommended as the optimal fin design for enhancing the efficiency of Ne‐PCM TES systems.

The catalytic electrocyclization of heptatrienes represents an attractive strategy to access seven-membered carbocycles from acyclic precursors, whose medium-size cyclic saturated hydrocarbon counterparts display physicochemical properties of interest for jet-fuel applications. Here we uncover the potential of alkali-metal amides to enable an efficient, high-yielding and multigram-scale electrocyclization of biobased ocimene and related trienes derived from isoprene. Experimental results show that both the nature of alkali metal (Li vs Na) and coordination by PMDETA (N,N,N',N″,N″-pentamethyldiethylenetriamine) play a decisive role in enabling efficient turnovers. Trapping and structural authentication of key metalated intermediates, together with DFT calculations, provide valuable mechanistic insights into the cyclization pathway and the factors governing reactivity. The transformation can proceed catalytically at relatively low loadings in neat conditions, with lithium-based catalysis providing selectively 1,1,4-trimethylcycloheptadienes albeit at higher catalyst loadings of 10 mol%, whereas sodium-based systems can operate at lower loadings of 2 mol% and can promote the isomerization/cyclization of other trienes.

Experimental evaluation of an innovative horizontal solar air heater incorporating thermal energy storage using paraffin wax, graphite, and internal reflector enhancements

A paraffin-wax-based system filled with sub-micrometer alumina particles is developed for use as impregnation of superconducting magnets operating at cryogenic temperatures. The addition of alumina fillers significantly enhances the thermal and cryo-mechanical performance of the wax matrix. Compared with pure wax, the filled system exhibits significant increases in compressive strength, elastic modulus and fracture toughness from room temperature down to its cryogenic service temperature. The filled wax retains a low melt viscosity, ensuring effective impregnation of coils, while the improved match in thermal expansion coefficient with other magnet components reduces the accumulation of local thermal stresses after cooldown. 2D representative volume element (RVE) simulations containing rigid particles embedded in the wax matrix were used to elucidate the mechanisms of damage initiation and stress evolution during thermal contraction and subsequent mechanical loading. The simulation results show good agreement with microscopic fracture observations and provide valuable insights for the design of mechanically robust and thermally compatible next-generation wax-based impregnation systems for superconducting magnets. • Paraffin-wax system filled with alumina developed for superconducting magnets. • 45 vol% alumina halves thermal contraction versus unfilled wax. • Filled wax retains low melt viscosity suitable for coil impregnation. • Tripled stiffness and compressive strength from ambient to cryogenic temperatures. • RVE simulations reveal thermal-mismatch stresses and matrix-particle damage.

• Comprehensive chemical analysis of Curlone and Kepone commercial formulations • Tentative identification of chlorinated compounds from isotopic pattern recognition • Tentative identification of non-halogenated compounds from fold change analysis • Better estimation of the possible overall exposure from use of these formulations Chlordecone (CLD) was widely used in French West Indies (FWI) until 1993 against black banana weevil ( Cosmopolites sordidus ). However, this pesticide was determined to have various adverse effects such as increasing the frequency of prostate cancer and impacting infant’s neurological development. It is thus a highly monitored compound in FWI environmental, food and biological matrices. CLD represents the major organic component (5% by weight) of the commercial formulations used in the past, although some other compounds are expected to be present. This study investigates the overall organic chemical composition of six Curlone formulations and of one sample of technical Kepone to identify compounds other than CLD that can be present in these formulations and still unknown. Chemical analysis was performed using both gas chromatography and liquid chromatography hyphenated with high resolution mass spectrometry, while data processing was conducted using non-target analysis. The overall investigation lead to the detection of 52 chlorinated molecules and 16 non-chlorinated molecules ranging from 1% to 1 part-per-million (ppm) of the CLD intensity. Tentatively identified compounds were some CLD isomers, mirex, chlordecol, monohydro- and/or dihydroCLD, chlorocyclopentadienes, chloronaphthalenes, chlorobutadienes, chloroindanes, chloroindenes and chlorocyclopentenes for chlorinated compounds, and cyclic hydrocarbons, oxygenated hydrocarbons and linear alkanes for non-chlorinated compounds. Even if some compounds were detected at low percentages, the high quantity used for these formulations in the French West Indies makes the overall quantity of these compounds non-negligible, and thus future studies could investigate these compounds in environmental, food and biological matrices.

The increasing adoption of bioplastics is rapidly expanding in food contact materials (FCMs) to minimise environmental impact and improve consumers' acceptance. However, several aspects must be considered throughout their lifecycle, from bioplastic processing to final product application. This study presents an untargeted analytical workflow to characterise volatile compounds of bioplastic FCMs based on GC-Orbitrap HRMS coupled with chemometrics and complemented by GC × GC-TOF-MS. The bio-based FCMs included polylactic acid (PLA), its heat-resistant variant crystallised PLA (cPLA) and no-PLA materials. The approach based on GC-Orbitrap HRMS coupled to supervised PLS-DA and variable importance in projection (VIP) method allowed the identification of differential compounds able to discriminate samples according to material composition and maximum end-use temperature. Chemometric analysis applied to samples classified according to maximum end-use temperature identified cyclic oligomers and hydrocarbons as markers for PLA samples suitable for use up to 40°C. Considering classification by the type of material resistant to moderate temperature (cPLA vs. no-PLA FCM), analysis of the dataset showed almost completely different VIP selection, with some PLA-related molecules (lactic acid, lactate esters, and linear oligomers) characterising cPLA, some hydrocarbons as key variables of the non-PLA class, and two succinate esters present in both the materials suggesting the presence of PLA/polybutylene succinate blends. In addition to polymer-related molecules, plasticisers emerged as chemical additives incorporated into theinvestigated materials during manufacturing. In addition, GC × GC-TOF-MS successfully identified distinct series of PLA oligomers, citric acid esters, and mineral oil saturated hydrocarbons, with regular chromatographic patterns, supporting structural hypotheses and integrating GC-Orbitrap HRMS findings.

Development of antimicrobial egg coatings for extending the shelf life of eggs using cassava starch blended with sodium alginate, liquid paraffin wax, and ZnO nanoparticles.

Performance of a mixed solar dryer integrated with pebbles and paraffin wax for drying lemon

Paraffins are attractive as phase-change materials (PCMs) due to their high latent heat capacity and adjustable phase transition temperatures. However, the individual high-purity paraffins, especially the long-chain ones, are labor-intensive and costly to produce and capable of storing and releasing latent heat only within a limited temperature range. Herein, we demonstrate the feasibility of a high-purity paraffin wax fraction (C13–C49) obtained via the Fischer–Tropsch (FT) process as a versatile latent heat storage additive within a wide range of phase transition temperatures (8.1–98.2 °C). To avoid the leakage, the FT wax was encapsulated via nanoemulsion interfacial polymerization of melamine formaldehyde (MF) shells with various core-to-monomer and melamine/formaldehyde ratios. Differential scanning calorimetry revealed that the latent heat storage capacity of the FT/MF capsules was 104.5–163.4 J/g depending on the FT loading efficiency, with the heat storage and release range of −0.7–100.2 °C and −9.8–85.8 °C, respectively. The capsules were tested as a thermoregulating additive to commercially available gypsum plaster. Unlike employment of the additives based on individual paraffins, the addition of FT/MF capsules led to a smooth reduction in heating/cooling rates of plaster layers in an extended temperature range. This makes FT/MF capsules a promising and versatile additive for a diversity of thermal energy storage applications.

The microwave permeability of composites containing microsized gadolinium powder in paraffin wax was studied as a function of frequency, temperature and gadolinium fraction for a series of composites with a powder volume fraction of 5% to 50%. The constitutive parameters of the composites were measured by the Nicolson–Ross–Weir technique in a standard 7 × 3 mm coaxial line in the frequency range of 0.1 to 10 GHz and the temperature range of 5 to 26 °C. In the indicated ranges, the permittivity was independent of frequency and temperature, and the real part of the permittivity only depended on the gadolinium powder volume fraction. It was found that the peak of the magnetic losses shifts towards lower frequencies with an increase in temperature. The Curie temperature of the composites found from the temperature dependence of the static permeability was close to 15 °C, being practically independent of the gadolinium volume fraction. To retrieve the intrinsic permeability of the filler particles, the Odelevsky mixing rule was used. The measured dependence of the static permittivity on the gadolinium volume fraction was in good agreement with the fitting by the Odelevsky mixing rule. Using the values of the percolation threshold and the depolarization factor obtained as a result of the fitting of the static permittivity, the frequency dependence of the intrinsic permeability of the filler particles was retrieved. The temperature effect on the intrinsic permeability was also analyzed. The obtained results may be useful for designing microwave devices, including temperature-tunable microwave screens and sensors.