Melting Enthalpy Research Articles

Incorporation of myrtle essential oil into hydrolyzed ethyl cellulose films for enhanced antimicrobial packaging applications

This research delved into examining the impact of hydrolysis and incorporation of Myrtle essential oil (MEO) on the film-forming and antimicrobial characteristics of ethyl cellulose polymer (EC). Three plasticizers (glycerol, mono ethylene glycol, and oleic acid) were evaluated for film-forming ability. The composite biofilms' structure was assessed through SEM, XRD, FT-IR, and DSC. Eventually, the combination of hydrolyzed EC with oleic acid yielded a flexible film with optimal thickness. Utilizing GC-MS analysis, α-pinene was identified as the predominant compound within MEO, conferring both antioxidant and antibacterial attributes. FTIR spectroscopy confirmed MEO's participation in the film-forming matrix through hydrogen bonding. By incorporating the MEO into the matrix, the WVP decreased significantly to 6.15*10–12 gmm/hmm2Pa considering that the hydrophobic feature of MEO can block the diffusion of water and decrease the WVP. The melting point and enthalpy of the polymer matrix containing MEO decreased that could be attributable to the EOs plasticizing impact, which increases the polymer chain mobility, and thereby hinders the strong interactions between polymer molecules. From the morphological finding, even at higher concentrations, MEO did not form agglomerations in the film matrix, highlighting its excellent compatibility with the microstructure of the resulting films. The film containing MEO showed the acceptable antioxidant activity. Furthermore, films containing MEO substantially decreased S. aureus biofilm development at 24 and 48 h, compared to P. aeruginosa and E. coli. These findings suggest potential applications of the developed film in packaging and preservation.

Influence of Mg Content on Microstructure Coarsening, Molten Pool Size, and Hardness of Laser Remelted Al(-x)-Mg-Sc Alloys.

Investigations leading to high-quality surfaces and optimized properties in laser remelted Al-Mg-Sc alloys remain scarce. Laser surface remelting (LSR) has been used for the final treatment of these alloys processed through additive manufacturing. However, the direct microstructure responses of the treated cast surfaces have not yet been investigated. In the present research, Al-3, 5, and 10 wt %-Mg-0.1 wt %-Sc alloys plates were processed using LSR to study the effects of local melting and rapid solidification. The morphology of the α-Al phase, microstructure coarsening, and hardness were mapped from the bottom to the top of the molten pools, varying with local Mg content and laser heat input (2.5 J/mm, 5 J/mm, and 10 J/mm). This study aimed to create a comprehensive map of the microstructures, hardness, and molten pool sizes under various conditions. The findings may help to optimize these alloys through understanding laser processing parameters. Methods used included CALPHAD computations, optical microscopy, SEM, EDS, image analysis, hardness tests, and heat flow models. The results obtained showed α-Al cell growth with bands in all alloys with hardness changes correlating with cell spacing and heat input. Higher Mg content resulted in more refined cells and a higher fraction of bands. Increased Mg content decreased the thermal diffusivity and enthalpy of melting, enlarging the molten pool size. Hardness increased with decreasing heat input and higher Mg content in the tested alloys, especially in the Al-10 wt %-Mg-0.1 wt %-Sc alloy as the heat input was varied.

Chiral liquid crystal dimers with smectic phases for stabilization of anticlinic state in surface-stabilised geometry

The growing demand for enhanced optical quality and faster electro-optical response in liquid crystal (LC) photonic devices has expanded the search for advanced materials capable of improving the properties of LCs beyond conventional ones. Among these compounds are LC dimers with ferroelectric and antiferroelectric properties which can be incorporated into LC mixtures to enhance performance. However, existing dimers often feature high melting temperatures, enthalpies, and other physicochemical characteristics that render them unsuitable as dopants in antiferroelectric liquid crystal (AFLC) mixtures targeted to modern photonic devices. Here, we show the design and physicochemical properties of novel dimers which are characterized by low melting points, high tilt angles and spontaneous polarizations, temperature-stable helical structures, and reasonably broad temperature ranges of ferroelectric or antiferroelectric phases. These features have facilitated the effective use of one dimer as a dopant in AFLCs. This eliminates the primary drawback of the electro-optical effect based on the surface-stabilised geometry of AFLCs by strongly promoting the anticlinic state in this effect. Importantly, for the first time, the above can be achieved without affecting any other physicochemical or optical properties of AFLCs. Thus, the obtained results represent a pivotal link between the longstanding concept of developing AFLCs that meet the stringent requirements for electro-optical effects based on surface-stabilised geometry and the realization of novel photonic devices demonstrating all the benefits of this effect.

Cellulose-reinforced foam-based phase change composites for multi-source driven energy storage and EMI shielding

To address the increasingly serious environmental pollution and energy crisis, there is an urgent need to develop multi-source-driven energy storage materials, the field of new energy sources, such as solar thermal power generation, but electromagnetic pollution has become a primary problem that needs urgent resolution. Therefore, the development of multifunctional phase change composites (CPCMs) with multi-source drive capabilities and excellent electromagnetic shielding integration is crucial. In this study, polypyrrole (PPy)-coated conductive fibers were crosslinked with polyvinyl alcohol (PVA) to form a three-dimensional network, which was then combined with metal foam to prepare Ni–F/PPy@CNF-PVA (PCN) dual-network carriers with high electrical conductivity by vacuum-assisted adsorption and freeze-drying methods. Polyethylene glycol (PEG) was subsequently encapsulated via vacuum impregnation to get the shape-stable PEG/Ni–F/PPy@CNF-PVA (PPCN) phase change composites. The PPCN exhibited good stability and high energy storage density (melt enthalpy up to 126.18 J/g, relative enthalpy efficiency over 99 %). Benefiting from its outstanding electrical conductivity (186680 S/m for PPCN-3), light-absorbing properties, and magnetism, the PPCN also exhibits highly efficient photothermal, electrothermal, and magnetothermal conversion capabilities. The electromagnetic interference shielding efficiency reaches up to 110.37 dB within the X-band frequency range (8.2–12.4 GHz). In conclusion, PPCNs are significant for multi-source-driven energy storage and electromagnetic shielding.

Development of a sustainable polymer composite: enhancing properties of waste plastic with ground tire rubber reinforcement

The growing interest in utilizing waste for composite development has prompted investigations across social, economic, and environmental domains. This study focuses on utilizing recyclable waste plastic materials and micro-sized ground tire rubber (GTR) of varying sizes (600 μm, 300 μm, and 150 μm) to create a polymer matrix composite (PMC). Employing a thermal blending technique, the manufacturing process adjusts the composition ratios of polymer and GTR from 90:10 to 50:50. Subsequently, Energy Dispersive Spectroscopy (EDS) is utilized to analyze the PMC composition, while Fourier-transform infrared spectroscopy confirms functional group and chemical structure. The study demonstrates significant improvements in various properties upon adding GTR to High-Density Polyethylene (HDPE) and Low-Density Polyethylene (LDPE) composite materials. For HDPE-GTR composites, the melting temperature (Tm) ranged from 120.29 °C to 138.53 °C, crystallization temperature (Tc) from 102.84 °C to 127.14 °C, and enthalpy of melting (ΔHm) from 70.96 to 139.67 J g−1. Crystallinity (Xc) varied from 48.43% to 52.96%. In LDPE-GTR composites, Tm ranged from 106.08 °C to 129.57 °C, Tc from 90.27 °C to 112.20 °C, ΔHm from 75.59 to 142.53 J g−1, and Xc from 51.59% to 54.05%. Moreover, mechanical properties such as tensile strength, flexural modulus, and impact strength exhibited enhancements with GTR addition to the polymer matrix. These findings underscore the potential of sustainable waste utilization, advancing environmentally friendly and resource-efficient composite materials.

Microfluidic fabrication of compound microfibers encapsulating nano-enhanced phase change material (PCM) for thermal regulation

This study presents a microfluidic approach for fabrication of compound phase change fibers (CPCFs) encapsulating nano-enhanced phase change material (PCM), RT25, for thermal regulation. The produced fibers are flexible and have strong compatibility and durable stability, with their size and the proportion of PCM can be precisely controlled by the microfluidic approach. Especially, a hydroxy surface modification method was used to uniformly disperse SiO2 nanoparticles into the RT25, aiming to enhance the thermal regulation performance of the CPCFs. Thermal performance test was conducted and it indicated that, compared with the compound phase change fiber (CPCF) with pure RT25, the CPCF incorporated with 2 wt% SiO2 nanoparticles presented a notable increase in thermal conductivity by 46.52 % and 45.51 % for solid-state and liquid-state enclosed PCM with a limited reduction in both melting and solidification enthalpies by 9.21 % and 10.1 %, respectively. Moreover, an experiment simulating the heat dissipation scenario of the electronic cabinet under intermittent running with short operation and long rest was conducted by using the CPCFs. It showed that adding SiO2 nanoparticles can improve the heat absorption process (solid-to-liquid phase) via the CPCFs with a smaller temperature increase (i.e., the maximum temperature of simulated inner electronic device in the cabinet for the repeated intermittent running) and it is also able to make the CPCFs renew (liquid-to-solid phase) more quickly and ready for heat absorption process in the next cycle. These CPCFs offer a promising alternative for more efficient and sustainable thermal management of the electrical/electronic equipment.

Solid-State Reaction of Alkylamines with CO2 in Ambient Air.

This paper explores possible procedures to accelerate CO2 capture from ambient air by a crystalline alkylamine surfactant (octadecylamine), leading to the corresponding crystalline ammonium-carbamate. Conversion of the amine to the carbamate, in different conditions, is studied by four different techniques: WAXD, FTIR, TGA, and DSC. The WAXD study also gives relevant information on the crystal structures of both amine and derived carbamate. Kinetics of reactions of the crystalline amine are mainly studied by DSC scans, by evaluating melting enthalpies of residual amine. The kinetics of conversion of the amine in ambient CO2 is strongly accelerated by ball milling with full conversion achieved after only 4 h, while the reaction kinetics of amine powder simply exposed to ambient CO2 is complete only after nearly 103 h. A substantial increase in kinetics of the solid-state amine reaction with ambient CO2 can be also achieved by increasing the temperature up to 50 °C, i. e. at a temperature slightly lower than amine melting. However, the time for full conversion remains much higher than for room-temperature ball-milled amine (roughly 102 h vs 4 h). Hence, suitable ball-milling procedures can lead to complete and relatively fast conversion of the crystalline amine to the crystalline ammonium-carbamate, even with ambient CO2.

Novel differential scanning calorimetry (DSC) application to select polyhydroxyalkanoate (PHA) producers correlating 3-hydroxyhexanoate (3-HHx) monomer with melting enthalpy.

Polyhydroxyalkanoate (PHA) is an environmental alternative to petroleum-based plastics because of its biodegradability. The polymer properties of PHA have been improved by the incorporation of different monomers. Traditionally, the monomer composition of PHA has been analyzed using gas chromatography (GC) and nuclear magnetic resonance (NMR), providing accurate monomer composition. However, sequential analysis of the thermal properties of PHA using differential scanning calorimetry (DSC) remains necessary, providing crucial insights into its thermal characteristics. To shorten the monomer composition and thermal property analysis, we directly applied DSC to the analysis of the obtained PHA film and observed a high correlation (r2 = 0.98) between melting enthalpy and the 3-hydroxyhexanoate (3-HHx) mole fraction in the polymer. A higher 3-HHx fraction resulted in a lower melting enthalpy as 3-HHx provided the polymer with higher flexibility. Based on this, we selected the poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P(3HB-co-3HHx)) producing strain from Cupriavidus strains that newly screened and transformed with vectors containing P(3HB-co-3HHx) biosynthetic genes, achieving an average error rate below 1.8% between GC and DSC results. Cupriavidus sp. BK2 showed a high 3-HHx mole fraction, up to 10.38mol%, with Tm(℃) = 171.5 and ΔH of Tm (J/g) = 48.0, simultaneously detected via DSC. This study is an example of the expansion of DSC for PHA analysis from polymer science to microbial engineering.

Silk Fabrics Modified with Photothermal Phase Change Microcapsules for Personal Thermal Management.

With the development of technology, personal heat management has become a focus of attention. Phase change fabrics, as intelligent materials, are expected to be widely used in multiple fields, bringing comfortable, intelligent and convenient living experience. In this study, miniature phase change microcapsules (MPCM) with n-octadecane as core and poly(methyl methacrylate) as shell were successfully prepared. Using the in-situ reduction property of polydopamine, gold nanoparticles were deposited on the surface of the microcapsules, which retained the heat storage function and imparted photothermal and antibacterial properties. The MPCM with photothermal conversion function was modified on the surface of silk fabric using aqueous polyurethane after verified by comprehensive material characterisation techniques. Under the near infrared light of 808 nm wavelength and 0.134 W/cm² irradiation intensity, the MPCM@PDA@Au modified silk fabrics showed excellent photothermal conversion performance, which could be increased from 25°C to 60°C in 50s. After the light source was cut off, the fabrics showed good heat release ability, with melting enthalpy and crystallisation enthalpy reaching 41.58 J/g and 43.3 J/g, respectively, which were not changed after repeated cycles. After the light source is cut off, the fabric has good heat release ability, and the enthalpy of melting and crystallisation reaches 41.58 J/g and 43.3 J/g, respectively, and the photothermal efficiency remains unchanged after many cycles of use, which proves that it has excellent durability and stability. The antimicrobial test shows that the fabric has significant antibacterial effect on Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). MPCM@PDA@Au silk fabrics bring new possibilities for the future of personal thermal management and antimicrobial protection in the field of medical health, outdoor sports and other areas of broad application prospects, heralding the birth of a series of innovative applications and solutions.

Effect of Different Types of Emulsifiers on the Physical Characteristics and Fat Bloom Stability of Dark Chocolate with Cocoa Butter Alternatives

An emulsifier is incorporated to delay the fat bloom formation and improve the overall quality of dark chocolate. This study aims to investigate the effects of different emulsifiers on the physical properties and stability of fat bloom in dark chocolate with cocoa butter alternatives (CBAs). Dark chocolate formulations were prepared containing different emulsifiers like lecithin, glycerol monostearate and a combination of both with CBAs like cocoa butter substitute (CBS) and cocoa butter replacer (CBR). Physical property analyses included hardness, snap texture, melting behaviour, pH, and water activity. The whiteness index was used to measure fat maturity. The results showed that the addition of lecithin, CBS, and CBR decreased the hardness value. Meanwhile, samples of chocolate formulation with the addition of glycerol monostearate (CB+GMS), and chocolate formulation with the addition of lecithin and glycerol monostearate (CB+2E), increased the hardness and snap texture. Besides, CBR increased the peak temperature, and emulsifiers increased the peak temperature in samples with CB and CBR while decreasing the melting enthalpy. Furthermore, the addition of CBA and emulsifiers improved the stability of the fat bloom. Therefore, mixed emulsifiers, which have favourable physical properties and higher fat bloom stability, are ideal for use in chocolate production. CBAs have the potential for practical application in chocolate production to improve fat bloom stability.

Phase change composite based on lignin carbon aerogel/nickel foam dual-network for multisource energy harvesting and superb EMI shielding

With the increasingly rapid pace of updates and iterations in electronic devices, electronic equipment/systems are becoming progressively intricate, aiming to achieve swift responsiveness through higher packaging density, which leads to electromagnetic interference and brings along with it heat accumulation, the creation of new composite phase change materials with efficient thermal management capabilities integrated with excellent electromagnetic interference shielding capabilities is imminent. In this study, nickel foam/lignin/rGO dual network scaffolds (LGN) with high electrical conductivity were prepared by vacuum-assisted adsorption, freeze-drying, and thermal annealing, and then PEG was encapsulated in LGN by vacuum impregnation to obtain shape-stabilized PEG/NiF/LN-rGO (PLGN) composite phase change material. The results demonstrate that the prepared PLGNs exhibit robust stability, exceptional thermal management capabilities, and commendable electromagnetic interference (EMI) shielding effectiveness (SE). Among these composites, PLGN-3 stands out with a notably high energy storage density, featuring a melting enthalpy of 140.95 J/g and a relative enthalpy efficiency of 98.72%. Benefiting from its outstanding electrical conductivity (1597.5 S/cm for PLGN-3) and superior light absorption, the PLGN composite phase change material also demonstrates highly effective photothermal and electrothermal conversion capabilities. In addition, the EMI shielding effectiveness reaches up to 69.9 dB at 8.2–12.4 GHz. In conclusion, the synthesized PLGN composite phase change material demonstrates considerable promise for mitigating electromagnetic interference and facilitating thermal energy management in electronic devices.

Experimental investigation of tailoring functionalized carbon-based nano additives infused phase change material for enhanced thermal energy storage

The advancement of phase change materials (PCMs) as potential thermal energy storage (TES) materials for building envelopes holds promise for efficient energy utilization. However, the PCMs have a major drawback during energy storage, which is lower thermal conductivity, leading to inadequate heat transfer performance and energy storage density. The foremost objective is to formulate a nanocomposite by dispersing functionalized multi-walled carbon nanotubes in salt hydrate PCM with the presence of surfactant. A two-step technique is employed to formulate the nanocomposites with different weight concentrations (0.2, 0.4, 0.6 and 0.8 %) of carbon-based nanoparticles and these nanocomposites are thoroughly characterized to explore the thermophysical properties. Resulting the nanocomposite demonstrates a significant improvement in thermal conductivity, increasing by 91.45 %, which can be attributed to the well-developed thermal networks with the PCM matrix. The nanocomposite samples exhibit extreme thermal stability up to 477 °C with a slight enhancement of 4.6 %. Optical investigations further confirmed that the transmissibility of PCM decreased to 8.3 % from 62.8 %, indicating an enhanced absorption capability due to the dark color nature of the nanoparticles. Moreover, the formulated nanocomposite demonstrated both chemical and thermal stability, with negligible changes in melting enthalpy even after 300 cycles of heating and cooling operations. Additionally, a numerical simulation analysis of 2D heat transfer was performed using Energy 2D software to demonstrate the efficacy of thermal conductivity in heat transfer. The thermally energized nanocomposite is suitable for medium-temperature TES applications such as photovoltaic thermal systems, building applications, textiles, electronic cooling, and desalination systems.

Graphene nanoplatelets-infused binary eutectic phase change materials for enhanced thermal energy storage

Energy depletion for the thermal regulation of buildings is a major global concern. Herein, we develop a binary eutectic phase change material (EPCM) consisting of sodium sulphate decahydrate (SSD) and sodium phosphate dibasic dodecahydrate (SPDD) that were modified using borax, carboxymethyl cellulose (CMC), and graphene nanoplatelets (GNP). In the EPCM, SSD, and SPDD were blended at a proportion of 62:38 to obtain a eutectic point of 27.8 °C with a melting enthalpy of 202 J/g. Borax was a nucleating additive to lessen the issue of supercooling, CMC was a thickening agent to ensure phase stability, and GNP was added as a nanomaterial to enhance the thermal behavior of EPCM. Microtopography, chemical stability, optical transmissibility and absorptivity, phase transition characteristic, thermal conductivity, energy storage potential, degree of supercooling, and thermal stability over 200 thermal cycles were tested and determined. Using scanning electron microscopy, the GNP microstructure and its interaction with EPCM are visualized to present the dispersion and formation of the thermal network. The nanocomposite EPCM also has chemical stability, which is aided by a 571% increase in optical absorbance and an 83.8% decrease in transmissibility. With GNP as a nanomaterial, owing to the well-developed thermal network, we achieve a 106% increment in thermal conductance from 0.464 W/m⋅K to 0.956 W/m⋅K; likewise, GNP acts as a conducting binder and enhances the intermolecular interaction leading to an increase in melting enthalpy from 202.4 J/g to 226 J/g. Finally, a numerical simulation of EPCM heating a thermic fluid flowing within a concentric tube with focus on the temperature contour is conducted for elaborating the potential of PCM towards TES systems.

Synthesis and characterization of biobased copolyesters based on pentanediol: (2) Poly(pentylene adipate‐co‐terephthalate)

AbstractTraditionally, most flexible food packaging is made of linear low‐density polyethylene (LLDPE) which cannot easily be recycled, nor will it degrade in a reasonable timescale. In this work, a biobased biodegradable polyester alternative was investigated as a possible replacement for LLDPE. High molecular weight poly (pentylene adipate‐co‐terephthalate) with a 40/60 adipic acid/terephthalic acid mole ratio was synthesized using direct esterification and polycondensation. Glycerol and hexane‐1,2,5,6‐tetrol were added as branching agents to better match the structure of the LLDPE which in turn might help the ability of these materials in film‐blowing. Thermal, mechanical, and rheological properties of the copolyesters were thoroughly investigated. All copolyesters had a weight‐average molecular weight of over 140,000 g/mol, which is necessary for proper rheology, and were thermally stable up to 350°C. The addition of branching agents led to a slight decrease in crystallinity, d‐spacing, melting temperature, enthalpy of melting, stress at break, and elongation at break. However, an increase in Young's modulus and complex viscosity at high frequency were observed compared to PPeAT60 without branching agent added. Although the improved crystallinity and mechanical properties of the copolyesters made them viable for film‐blowing, the slow crystallization rate creates a major challenge.Highlights Linear and branched poly(pentylene adipate‐co‐terephthalate) (PPeAT) synthesized. Properties compared to commercial poly(butylene adipate‐co‐terephthalate) (PBAT). Glass and melting temperatures comparable to commercial PBAT. Extensional and shear viscosity comparable to commercial PBAT. PPeAT stiffness is factor of 2 higher than PBAT; ultimate properties similar.

Polymorphism in 5-methylsalicylic acid: Insights into relative thermal behavior, luminescent properties, crystal structure, and Hirshfeld surface analysis

Polymorphs play an important role in mediating the physical and chemical properties of compounds. Three polymorphs were obtained from different solvents used in crystallization. A new polymorph of 5-methylsalicylic acid (γ-MSA) were obtained from acetic acid. The polymorphs α-MSA and β-MSA crystallized from water, and the mixed solvent containing methanol and water, respectively. The novel morphology of γ-MSA has been characterized by single–crystal X–ray diffraction, IR spectroscopy data, and powder X-ray diffraction. Single-crystal X-ray diffraction analysis shows that γ-MSA belongs to the monoclinic system with the P21/c space group. The parameters are listed as the following: a = 7.2795(5) Å, b = 15.2560(7) Å, c = 6.7170(4) Å, β=100.834(7)°, V = 762.83(8) Å3. In the novel polymorphic structure, classical hydrogen bonds of O–H···O can be obviously observed, through which a supramolecular architecture will be generated. Apart from the classical hydrogen bonds, the weak hydrogen bonds of C–H⋯O can be only found in form γ-MSA. The luminescent maximal are 394, 398 and 406 nm for α-MSA,β-MSA and γ-MSA, respectively. The order of the luminescent maximal peaks is listed as the following: α<β<γ. Single-crystal X-ray diffraction analysis results reveal that the order of the stacking interactions and the dihedral angles occurred between the carboxylic group and phenyl ring presents the following: α<β<γ. The Hirshfeld analysis further confirms that there exists the same sequence of the C···H intercontacts in α-, β- and γ-polymorphs. The contribution of the H···O/O···H close contacts in γ-MSA is the largest among these polymorphs, being confirmed by differential scanning calorimeter (DSC) data, which is in a good agreement with that of melting point. On the basis of analysis of DSC data and the fusion rules, the enthalpies (ΔH) and entropies (ΔS) can be estimated to be 29.5 kJ mol-1 and 69.4 J K-1 mol-1 for α; 31.1 kJ mol-1 and 72.8 J K-1 mol-1 for β, and 35.4 kJ mol-1 and 74.5 J K-1 mol-1 for γ), and these polymorphs are monotropically related. The sequences of melting point, enthalpies and entropies can be proposed: α<β<γ.

Experimental investigations and thermodynamic modelling of the ternary system Pb-Mo-O

A combined experimental and modelling study into the Pb-Mo-O system has been conducted in view of the safety analysis for lead-cooled nuclear systems. The thermal expansion and low-temperature heat capacity of the ternary compounds PbMoO4 and Pb2MoO5 have been determined experimentally, as well as the melting enthalpy of PbMoO4. Moreover, XANES measurements have confirmed the hexavalent oxidation state of Mo in PbMoO4 and Pb2MoO5.A thermodynamic model of the ternary system including the ternary phases PbMoO4, Pb2MoO5 and Pb5MoO8 has also been developed in this work based on the CALPHAD methodology. For the first time, an ionic two-sublattice model is used for the liquid phase, while the compound energy formalism is used for the solid phases.

Surface structure-based model to calculate thermal and optical properties in nanoscale and quantum dot semiconductors

Surface combination structure was used to design the construction of nano and quantum films, particles, and dots. The created model was applied to tetrahedral semiconductor nanoparticles and quantum dots with a successful performance. It works better than reported experimental data across the whole size range, from the bulk state to the critical size of quantum dots. The model helps to figure out the melting point that changes with the nanosize scale as applied on Si and Sn, which are simple tetrahedral semiconductors, and for CdS and CdSe, which are among II-VI group compounds. It was also used to calculate melting-related parameters such as cohesive energy, Debye temperature, vibrational entropy, and melting enthalpy. The nanosize dependence of the lattice volume and the atom's ionization energy describes the solid surface structure. From the model, an equation was obtained to calculate the energy gaps in Si, CdS, and CdSe particles that are nano- and quantum-dot-sized, and the results are compared to the experimental data that goes with these particles.

Hydrogel encapsulation facilitates a low-concentration cryoprotectant for cryopreservation of mouse testicular tissue

Cryopreserved testicular tissue offers a promising method to restore fertility in male infertility patients. Current protocols rely on high concentrations of penetrating cryoprotectants (pCPAs), such as dimethyl sulfoxide (DMSO), which necessitating complex washing procedures and posing risks of toxicity. Hydrogel encapsulation presents a non-toxic alternative for cellular cryopreservation. This study investigates the effects of various types, concentrations, and thicknesses of hydrogel encapsulation on the cryopreservation of mouse testicular tissue. Testicular tissues loaded with varying concentrations of DMSO were encapsulated in alginate or gelatin-methacryloyl (GelMA) hydrogels. We evaluated hydrogels as potential CPAs to reduce pCPA concentrations and determine optimal combinations for cryopreservation. Post-cryopreservation, tissues were cultured using organ culture methods to assess spermatogenesis progression. Cryomicroscopy and differential scanning calorimetry (DSC) were used to examine ice crystal formation, melting enthalpy, and non-freezing water content in different hydrogels during cooling. Results indicate that 3 % alginate or 5 % GelMA hydrogel with thin encapsulation optimally preserves mouse testicular tissue. Using 20 % DMSO in 5 % GelMA thin encapsulation showed comparable apoptosis rates, improved morphology, higher mitochondrial activity, and enhanced antioxidant capacity compared to conventional 30 % DMSO without encapsulation. This suggests that hydrogel encapsulation reduces pCPA concentration by 10 %, thereby mitigating toxic damage. Hydrogel encapsulation can reduce basement membrane shrinkage of testicular tissue during cryopreservation. Moreover, frozen tissues remained viable with preserved germ cells after being cultured for one week on alginate methacryloyl (AlgMA) hydrogel using the gas-liquid interphase method. Cryomicroscopy and DSC studies confirmed the hydrogel's ability to inhibit ice crystal growth. In conclusion, this study introduces novel strategies for male fertility preservation and advances cryopreservation technology for clinical applications in assisted reproduction.

Binary eutectic phase change materials application in cooling asphalt: An assessment for thermal stability and durability

Organic eutectic phase change materials (PCM) show great promise as thermal storage agents for regulating the temperature of asphalt pavements. Assessing their aging characteristics and durability when integrated into asphalt is crucial and necessitates further in-depth research. This study evaluates the impact of aging on binders with acid/palmitic acid binary eutectic PCM (SA/PA-PCM). Aging was simulated using the rolling thin film oven (RTFO) and pressure aging vessel (PAV) devices. The current study leads to the conclusion that the use of SA/PA-PCM is promising. Specifically, the incorporation of SA/PA-PCM significantly improves the aging resistance, showcasing notable enhancements in thermal stability, fatigue performance, anti-cracking ability, and thermal regulation of asphalt. Only a 5 % decrease occurred in the melting enthalpy of the binder with 15 % SA/PA-PCM after 60 h of long-term aging (from 32.17 to 25.87 J/g), showing a stable thermal storage ability. The maximum temperature difference and lag is 9.3 °C and 46 min. respectively. To sum up, Asphalt with 15 % SA/PA-PCM surpasses other binders, displaying higher melting latent heat, reduced sulfoxide index, increased long-term aging resistance, and superior stress relaxation capabilities. This research confirms the potential of SA/PA-PCM in asphalt applications, providing a new path for durable and environmentally friendly road infrastructure.

Folic acid in carboxymethylcellulose/polyethylene oxide electrospun nanofibers: preparation, release and stability.

Folic acid (FA), a synthetically produced compound analogous to vitamin B9, also referred to as vitamin folate, is an essential compound in human health and faces challenges in stability during food processing. This study explores the incorporation of FA into carboxymethylcellulose (CMC) nanofibers using electrospinning to enhance its stability. In this study, optimization of both electrospinning and solution parameters facilitated the fabrication of nanofibers. Furthermore, incorporating FA into CMC/polyethylene oxide (PEO) nanofibers resulted in thinner fibers, with an average diameter of 88 nm, characterized by a flat shape and smooth surface. Fourier transform infrared spectroscopic analysis demonstrated substantial hydrogen bonding interactions between FA and the polar groups present in CMC. This interaction contributed to an encapsulation efficiency of 94.5%, with a yield exceeding 87%. Thermal analysis highlighted mutual interference between CMC and PEO, with FA enhancing the thermal stability and reducing the melting temperatures and enthalpies of PEO, while also increasing the reaction heats of CMC. The encapsulated FA remained stable in acidic conditions, with only 6% degradation over 30 days, demonstrating the efficacy of CMC/PEO nanofibers in safeguarding FA against acidic environments. Moreover, the nanofibers provided a protective barrier against UV radiation, thereby preserving the stability of FA. This study emphasizes the efficacy of CMC/PEO nanofibers as a protective matrix against FA degradation. The findings indicate that this innovative approach could significantly diversify the applications of FA in food fortification, addressing concerns regarding its vulnerability to temperature and hydrolysis reactions during food processing. © 2024 Society of Chemical Industry.