Thermal Characterization Research Articles

Structured illumination with infrared imaging for measuring thermal conductivity

With developments in advanced manufacturing and materials by design comes the need for high-throughput thermal characterization and inspection. Towards this end, Structured Illumination with Thermal Imaging (SITI) is an all-optical pump-probe thermal characterization technique recently developed by our group. In the first generation [Zheng et al., Appl. Phys. Rev. 9, 021411 (2022)] SITI uses an LED with a digital micromirror device (DMD) to “structurally illuminate” and heat the sample with dynamic patterns, a visible light camera for thermoreflectance based “thermal imaging” [leveraging a Microsanj MTIR120], and the resultant temperature response was fit with a thermal model to characterize the sample’s thermal properties. This represents a novel approach to dynamic and flexible spatial mapping of thermal properties by virtue of being a non-contact technique and having a simpler scanning means (computer control only) than conventional pump-probe laser methods. SITI also can tolerate rough samples with diffuse reflections. This talk presents the second generation of SITI. The pumping is now based on a lower cost off-the-shelf digital projector. The thermometry is now performed using an infrared (IR) camera, which we find is a more flexible and accessible hardware approach compared to the thermoreflectance microscopy used previously. With these updates the setup can deliver higher heating power and a broader range of frequencies, allowing an extended range of samples that can be studied. We have demonstrated SITI’s ability to measure the thermal conductivity of a microscope glass slide.

Advancing thermochemical storage: synthesis and characterization of cement-based composite materials

Thermal Energy Storage (TES) is crucial for sustainability of the energy sector, yet the development of cost-effective, robust materials remains a significant challenge. This study aims at exploring the synthesis and thermal characterization of cement-based composites for seasonal thermochemical energy storage, with the goal to harness the high energy density of hygroscopic salts while mitigating their limitations. We investigate composites with several cement matrices to improve salt-cement compatibility. Furthermore, we investigate the possible incorporation of porous low-cost compounds to enhance porosity and improve economic aspects. As far as the characterization aspects are concerned, we show experimental adsorption isotherms at different temperatures to estimate key material properties like isosteric heat and water uptake, along with the relevant figures of merit such as energy density. Our research leverages on adjustable porosity and affordability of cement as a host matrix for the ‘active phase’. We studied two synthesis approaches: traditional dry impregnation and an in-situ technique suitable for cements. The in-situ method, being straightforward and reproducible, permits greater control over salt content. Preliminary cost analysis positions these composites competitively in the market. Although we are still at sub-optimal stage, potential cost reduction of some less popular cement matrices suggests an opportunity for improvement.

Glass–Carbon–Kevlar fiber reinforced hybrid polymer composite (HPC): Part (A) mechanical and thermal characterization for high GSM laminates

The quest for light weight hybrid polymer composites (HPC) has resulted into multiple materials and structural configurations for achieving high performance in automotive and aerospace applications. Incidentally, the past reported work has (in general) involved variable GSM while investigating reinforced fiber layers. The variable GSM may lead to a random response of each layer to the applied forces and thermal degradation, due to which attributing the role of various layers to results/properties is difficult to ascertain. This research employs a uniform/consistent approach with high GSM (400) based HPC with multiple stacking sequences of glass (G), carbon (C), and Kevlar (K) to investigate thermo-mechanical properties. The research first focuses on fabrication of eleven stacking sequences of hybrid combinations, followed by identification of an optimal sequence based on mechanical (tensile strength, flexural strength, charpy impact resistance) and thermogravimetric analysis (TGA) characterization. Additionally, scanning electron microscopy (SEM) for fracture mechanisms of hybrid composites showing fiber pull out, matrix crack, and delamination. Results show that the tertiary combination having 2 Glass, 5 Carbon and 5 Kevlar layers (G2C5K5) named H9 herein provides a good balance of tensile, flexural, impact resistance and thermal properties; its deviation from the best of each category is within approximately 5, 13.5, 9.9 and 10.9 % (for tensile, flexural, impact, TGA) respectively. The range of properties evaluated in this study is deemed suitable for lightweight aircraft structures.

Development and characterization of a composite material with geopolymer matrix obtained by incorporation of microparticles from plastic bottles

The composite material with a geopolymer matrix of 7 M molarity, obtained by incorporating microparticles from plastic bottles is developed and characterized in the present paper. To do this, we made cylindrical specimens whose the diameters are the half of their heights and stored them at a temperature of (31±2°C). The compression test using a hydraulic press is carried out, as well as the thermal characterization test using a device respecting the experimental method of the asymmetric hot plane, which was used to determine the thermal conductivity, the volumetric heat capacity, the effusivity and the diffusivity. Then optical characterization tests on hardened samples were carried out, namely chemical analyses of the composition of the kaolin, and particle size characterization of the raw microscopic imaging of the specimens. The results found showed that as the amount of polyethylene terephthalate increases, the compressive strength decreases by 33.65 % for 10%polyethylene terephthalate and 67.77 % for 20 % polyethylene terephthalate. According to the thermal conductivity, it improves with the percentage of polyethylene terephthalate added as: at 10% it is 1.19Wm−1K−1 and at 20%, one has 0.595Wm−1K−1; similarly for effusivity where we obtained 1376.05 JK−1m−2s−1/2 and 560.81 JK−1m−2s−1/2 for 0 and 20% respectively. According to these results, the use of polyethylene terephthalate aggregates as a partial substitute of aluminosilicate raw material for the development of a composite can be a good alternative for recycling plastic bottle waste. The composite obtained could be used for the manufacture of ceiling lights and brick facings, and therefore would significantly reduce the amount of waste plastic produced every day in environment.

Morphological and Thermal Characterization of Low-Cost Graphene Produced by Electrochemical Exfoliation Method

The low-cost and mass production of graphene has gained importance in recent years. The electrochemical exfoliation method, one of the graphene production methods, is an efficient technique used to obtain low-cost-effective and large quantities of graphene nanosheets. Exfoliation parameters affect the properties of exfoliated graphene nanosheets. In this study, graphene production is fabricated by the method of exfoliation using electrolyte and voltage parameters. For this, a pen tip was used instead of pure platinum, which is very expensive, at the cathode. The structural research was done by X-ray diffraction spectroscopy (XRD), Raman spectroscopy and Fourier Transform Infrared Spectrometer (F-TIR). Morphological analyses were carried out by Scanning Electron Microscopy (SEM). The number of layers and crystallite of graphene layers were estimated. The obtained results were compared with the results of the other similar studies. Analysis results show that low-cost multilayer graphene can be produced by the electrochemical exfoliation method with the electrical parameters.

HERCCULES: A university balloon-borne experiment for BEXUS 32 to characterize the thermal environment in the stratosphere using COTS

The thermal analysis of stratospheric balloon payloads is still a complex task due to the variable thermal environment during the flight phases as well as due to the convective effects during the ascent. An experiment named HERCCULES has been successfully launched from Esrange Space Centre (Kiruna, Sweden) in September 2023 as part of the REXUS/BEXUS programme. This experiment aimed of serving as a heat transfer and thermal environment characterization platform that allow to validate previously developed methodologies for the worst-case thermal environmental conditions’ selection and the thermal analysis of these platforms. The experiment has been developed in an academic environment and the design, manufacturing, integration and test activities were mainly performed by Bachelor, Master and Ph.D. students with the mentorship of the European Space Agency. A low-cost design was achieved by using Commercial Off-the-Shelf (COTS) without compromising its performance capabilities. The obtained measurements show a colder behavior of the external elements with regard to the worst-case analysis during the first part of the ascent phase. In addition, radiative fluxes measured during the flight show a deviation in the infrared downward flux of about -50Wm−2 at 5km of altitude and a maximum fluctuation of about the 20% in the solar fluxes measurements. Significant advancements have been made for similar missions in terms of mechanical standardization, the use of COTS sensors and electronic components, the improvement of the reliability of the thermal analysis and the development of a software design adhered to standards and recommendations for critical systems.

Effect of Ag Nanoparticle on PLA/PEG Blend: A Study of Physical, Thermal Characterization, Shape Memory Assessment and Antimicrobial Properties

Effect of Ag Nanoparticle on PLA/PEG Blend: A Study of Physical, Thermal Characterization, Shape Memory Assessment and Antimicrobial Properties

Analysis of structural, optical, mechanical properties and evaluation of radiation shielding effectiveness of strontium borate glasses doped with ZnO nanoparticles

This research meticulously explores the synthesis, structural, thermal and optical characterization of zinc oxide nanoparticles (NPs) infused strontium borate glasses (termed SZ glasses) and their applicability as radiation shielding. The glasses have been produced using the melt quenching process in the composition series of (60-x)B2O3: xZnO: 10SrO: 10Na2O: 10CaO: 10BaO, where x varied from 0 to 20 % mol. In order to dope ZnO into glasses, its structural and morphological characteristics were investigated after it was synthesized by solution combustion method. It was found that the inclusion of ZnO significantly impacted the glasses' density, molar volume, hardness, yield stress, and thermal stability. The optical properties of the produced glasses, such as transmittance, reflection, transparency, opacity and band gap energies, were examined and the effect of ZnO on the optical properties of the glasses was investigated. Crucially, the SZ glasses exhibited notable efficiency in shielding against gamma photons and fast neutrons. This is evidenced by the favourable change in the mass attenuation coefficients with increasing ZnO concentration. Parameters like the half-value layer, effective atomic number, and energy absorption buildup factors were calculated to gauge the radiation attenuation proficiency of the SZ glasses, demonstrating their potential utility in radiation protection. In conclusion, the developed SZ glasses display advantageous structural, thermal, and optical qualities, along with robust shielding capabilities against gamma photons and fast neutrons. This study contributes significant knowledge to the field of novel glass materials, paving the way for their application in various industrial and medical contexts requiring radiation shielding.

Analysis of Adaptability and Application Potential of Supercritical Multi-Source Multi-Component Thermal Fluid Technology for Offshore Heavy Oil in China

Supercritical multi-source, multi-component thermal fluid is a heavy oil thermal recovery method independently developed by China National Offshore Oil Co., Ltd (Beijing, China). It uses waste liquid at the production end of the production well as the water source, the injection medium temperature exceeds 374 °C, 22.1 MPa, and all the produced flue gas is re-injected. Compared with steam huff and puff technology, supercritical technology has the advantages of high enthalpy value, high heat utilization rate, good oil displacement effect, and being green and pollution-free. In addition, its oil–water treatment cost is low, it can realize the reuse of organic matter, it has a good cost advantage of water treatment under the background of low carbon, and it is a thermal recovery method with great application potential for offshore heavy oil. Therefore, it is necessary to carry out research on the adaptability and application potential of supercritical multi-source, multi-heat flow thermal recovery technology in the sea. Based on the laboratory one-dimensional displacement experiment, this paper reveals the mechanism of heavy oil supercritical multi-source multi-component thermal fluid displacement and the contribution of supercritical components to the displacement effect, and establishes the supercritical multi-source, multi-component thermal fluid numerical simulation characterization method. Combined with the characteristics of offshore heavy oil reserves, the main control factors affecting supercritical multi-source, multi-component thermal fluid development were established by numerical simulation and orthogonal test methods, and the adaptive screening method of offshore supercritical technology was established. The application potential of 670 million tons of offshore heavy oil reserves was evaluated and sorted, and KL 10-2 oilfield was selected as the pilot test oilfield. The results show that supercritical technology has great advantages in oil displacement and water treatment cost reduction, and the results play an important guiding significance for the development of offshore heavy oil technology system and the iteration of new technology.

Tris(2-hydroxyethyl)ammonium-Based Protic "Ionic Liquids": Synthesis and Characterization.

The proton transfer associated with the synthesis of protic ionic liquids (PILs) is often incomplete, meaning that the parent compounds may coexist with the ionic species. However, PILs are proposed for many applications as pure compounds without analysis of their ionicity. This work focuses on tris(2-hydroxyethyl)ammonium-based PILs with lactate, hydrogen succinate, hydrogen malate, and dihydrogen citrate anions. The interest of these anions lies in their low toxicity and capacity to disrupt the hydrogen-bonding network inherent to biopolymers. To improve current synthesis methods of this kind of PILs, which frequently lead to impurities derived from decomposition of reactants, working in the absence of solvents and at moderate temperatures is proposed. Through NMR studies, the ionicity of these systems was found to be low, from 20% to 86%, so the widely used term "ionic liquid" is not rigorous and must be used with caution. The un-ionized acid and base species coexist with the corresponding ionic forms, and this has to be considered in the studies involving these chemicals. The thermal characterization of the PILs was carried out. The influence of the anion on the thermal stability was found to be low. Isothermal thermogravimetric analysis showed that mass loss of these PILs starts at temperatures close to 350 K.

Multiple Stress Creep Recovery of High-Polymer Modified Binders: Consideration of Temperature and Stress Sensitivity for Quality Assurance/Quality Control Policy Development

High polymer-modified binders (HiPMBs) have recently been introduced in the Gulf region, where pavement structures are commonly subjected to severe climate conditions and heavy traffic loads because there is no enforcement of weight limits. Local agencies are currently modifying quality assurance/quality control (QA/QC) policies to accommodate such technology. In this study, HiPMBs produced by different refineries were subjected to physicochemical and thermal characterizations to investigate the compositional variability of industrial HiPMBs. Their thermal and stress susceptivity was then assessed through multiple stress creep recovery (MSCR) tests. The validation of the MSCR-based hierarchy was performed by assessing nine hot mix asphalts (HMAs) through repeated load permanent deformation tests and performing mechanistic-based structural analysis. Results showed that styrene-butadiene-styrene (SBS) is not the only modifier added to the bitumen, as commonly done in laboratory settings. These undisclosed modifiers disrupt the correlation between MSCR results and SBS concentration typically observed in laboratory-prepared HiPMBs, highlighting the importance of investigating plant-produced binders. Moreover, higher temperatures and stress levels returned different MSCR performance hierarchies among binders, questioning the effectiveness of the current MSCR test protocol for HiPMBs. Additionally, findings confirmed that the current MSCR testing protocol does not correctly assess the bitumen response in HMAs. A higher MSCR stress level shall be prescribed in the local QA/QC specifications to ensure the correct selection of HiPMBs in the region. This study can be used as a framework for other countries actively engaged in the implementation of HiPMBs and novel bituminous materials.

Thermal structural damage and thermal decomposition characterization of GAP propellants with nitrate ester plasticizers

AbstractGAP and nitrate ester compounds are introduced into the solid propellant formulation as energetic binders and energetic plasticizing agents, respectively, to further enhance the energy level of solid propellants. However, under abnormal thermal conditions, various components within GAP propellants, especially nitrate ester plasticizers, can collectively result in the generation of a large number of voids within the propellant due to factors such as thermal stress and slow component decomposition. This phenomenon can impact the safety of solid rocket engines, necessitating research into their thermal decomposition processes and thermal damage structures. In this study, the thermal decomposition characteristics and gas products of GAP propellants with different nitrate ester plasticizer formulations were investigated using DSC‐TG and FT‐IR. The damage structure of GAP propellants heated under unignited conditions was studied through Micro‐CT, examining the influence of heating conditions and nitrate ester plasticizers on the thermal damage structure of GAP propellants. During heating, the thermal damage structure of GAP propellants was found to include voids generated within the GAP binder and cracks at the interface between the GAP binder and particles, with nitroglycerin as a plasticizer exacerbating the thermal damage of GAP propellants (about 2.2–2.9 times).

The growth aspects and experimental techniques for the characterization of amino acid L-histidine hybrid crystals for nonlinear optical device applications

The development of crystal growth and measurement methods opens new possibilities for studying materials with remarkable nonlinear optical features. The development of bulk crystals is a constant concern to be beneficial for device applications. This study focuses on the development of nonlinear optical crystals of l-histidine complexes, characterization approaches, and prospective applications. The solution growth approach, a straightforward, inexpensive, and low-temperature growth technique, was adopted broadly. Recent studies show that l-histidine derivatives have potential optical, SHG, thermal, dielectric, and mechanical properties, making them an excellent choice for nonlinear optical devices. In this work, structural, spectroscopic, chemical composition, linear and nonlinear optical analyses, thermal, and dielectric characterizations of l-histidine derivatives were conducted. Most of the l-histidine complexes were found to be crystallized in orthorhombic and monoclinic crystal systems with P212121 and P21 space groups. The crystalline perfections of the samples were analyzed by the HR-XRD method. The energy-dispersive X-ray (EDX) spectroscopic technique was applied to evaluate the chemical content of the compounds. FT-IR and FT-Raman techniques were used to recognize the molecular vibrations and functional groups of the l-histidine derivatives. The UV-visible and photoconductivity studies were done to examine the optical behaviors of the developed crystals. Most of the crystals were found to have excellent optical transparency and wide bandgaps. It has been observed that l-histidine hydro-fluoride dehydrate and l-histidine tetrafluoroborate are found to have the highest second harmonic generation (SHG) efficiencies. The dielectric analyses were utilized to study the dielectric constant and dielectric loss variations with the applied frequency. According to the thermal analyses, most of the crystals were found to have substantial thermal stabilities suitable for device applications.

Characterization of Biodegradable Polymers for Porous Structure: Further Steps toward Sustainable Plastics.

Plastic pollution poses a significant environmental challenge, necessitating the investigation of bioplastics with reduced end-of-life impact. This study systematically characterizes four promising bioplastics-polybutylene adipate terephthalate (PBAT), polybutylene succinate (PBS), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), and polylactic acid (PLA). Through a comprehensive analysis of their chemical, thermal, and mechanical properties, we elucidate their structural intricacies, processing behaviors, and potential morphologies. Employing an environmentally friendly process utilizing supercritical carbon dioxide, we successfully produced porous materials with microcellular structures. PBAT, PBS, and PLA exhibit closed-cell morphologies, while PHBV presents open cells, reflecting their distinct overall properties. Notably, PBAT foam demonstrated an average porous area of 1030.86 μm2, PBS showed an average porous area of 673 μm2, PHBV displayed open pores with an average area of 116.6 μm2, and PLA exhibited an average porous area of 620 μm2. Despite the intricacies involved in correlating morphology with material properties, the observed variations in pore area sizes align with the findings from chemical, thermal, and mechanical characterization. This alignment enhances our understanding of the morphological characteristics of each sample. Therefore, here, we report an advancement and comprehensive research in bioplastics, offering deeper insights into their properties and potential morphologies with an easy sustainable foaming process. The alignment of the process with sustainability principles, coupled with the unique features of each polymer, positions them as environmentally conscious and versatile materials for a range of applications.

Thermal Characterization and Preclinical Feasibility Verification of an Accessible, Carbon Dioxide-Based Cryotherapy System.

To investigate the potential of an affordable cryotherapy device for the accessible treatment of breast cancer, the performance of a novel carbon dioxide-based device was evaluated through both benchtop testing and an in vivo canine model. This novel device was quantitatively compared to a commercial device that utilizes argon gas as the cryogen. The thermal behavior of each device was characterized through calorimetry and by measuring the temperature profiles of iceballs generated in tissue phantoms. A 45 min treatment in a tissue phantom from the carbon dioxide device produced a 1.67 ± 0.06 cm diameter lethal isotherm that was equivalent to a 7 min treatment from the commercial argon-based device, which produced a 1.53 ± 0.15 cm diameter lethal isotherm. An in vivo treatment was performed with the carbon dioxide-based device in one spontaneously occurring canine mammary mass with two standard 10 min freezes. Following cryotherapy, this mass was surgically resected and analyzed for necrosis margins via histopathology. The histopathology margin of necrosis from the in vivo treatment with the carbon dioxide device at 14 days post-cryoablation was 1.57 cm. While carbon dioxide gas has historically been considered an impractical cryogen due to its low working pressure and high boiling point, this study shows that carbon dioxide-based cryotherapy may be equivalent to conventional argon-based cryotherapy in size of the ablation zone in a standard treatment time. The feasibility of the carbon dioxide device demonstrated in this study is an important step towards bringing accessible breast cancer treatment to women in low-resource settings.

Li-Ion Battery Thermal Characterization for Thermal Management Design

Battery design efforts often prioritize enhancing the energy density of the active materials and their utilization. However, optimizing thermal management systems at both the cell and pack levels is also key to achieving mission-relevant battery design. Battery thermal management systems, responsible for managing the thermal profile of battery cells, are crucial for balancing the trade-offs between battery performance and lifetime. Designing such systems requires accounting for the multitude of heat sources within battery cells and packs. This paper provides a summary of heat generation characterizations observed in several commercial Li-ion battery cells using isothermal battery calorimetry. The primary focus is on assessing the impact of temperatures, C-rates, and formation cycles. Moreover, a module-level characterization demonstrated the significant additional heat generated by module interconnects. Characterizing heat signatures at each level helps inform manufacturing at the design, production, and characterization phases that might otherwise go unaccounted for at the full pack level. Further testing of a 5 kWh battery pack revealed that a considerable temperature non-uniformity may arise due to inefficient cooling arrangements. To mitigate this type of challenge, a combined thermal characterization and multi-domain modeling approach is proposed, offering a solution without the need for constructing a costly module prototype.

Analysis of the thermal performances of uninsulated and bio-based insulated compressed earth blocks walls: from the material to the wall scale

The lively international debate on the future of the built environment has placed emphasis on the possibilities offered by bio and geo-based building materials. Among these, raw earth-based materials offer several advantages associated to their reusability and low embodied energy.Nowadays, several companies are basing their production lines on prefabricated raw earth products, as is the case of compressed earth blocks (from now on CEBs). CEBs are commercialized for the construction of massive vertical envelopes, characterized by a high thermal inertia. Nevertheless, in order to compete with conventional building materials, it is also necessary to guarantee a high thermal resistance.In this work, this issue was solved by the design and testing of full-scale uninsulated and bio-based thermal insulated CEB walls. In this way, the thermal performance of CEB walls can be increased to meet the high energy requirements currently adopted in European Countries. Furthermore, the choice of bio-based insulations represents the main novelty of the study, aimed at finding hygrothermal compatible solutions at a low environmental cost.More in detail, this work reports the results of the thermal and physical material characterization of CEBs and of two innovative bio-based thermal insulations (lime hemp and sugarcane bagasse panels), and compare them with measurements made on full-scale uninsulated and insulated CEB walls. For this purpose, the walls are tested inside a double-room climatic chamber where they are subjected to variable temperatures on their two faces, reproducing typical indoor and outdoor conditions during summer and winter conditions in a continental climate.Results show the enhancement of thermal performances of compressed earth blocks walls when thin layers of bio-based thermal insulations are added. The thermal resistance of weakly bio-based insulated CEB walls is found to be nine times (for the sugarcane bagasse insulated CEB wall) and four times (for the lime hemp insulated CEB wall) higher than that of uninsulated CEB walls. Moreover, the addition of the insulation layers enhances the time lag and the decrement factor values of CEBs walls.

Industrial byproducts as adhesive allies: Unraveling the role of proteins and isocyanates in polyurethane wood bonding

Wooden structures are becoming increasingly popular in the construction world. However, these structures often rely on synthetic adhesives, raising concerns about the environmental risks associated with their chemical composition. In response to these concerns, this study aims to explore sustainable alternatives, particularly focusing on polyurethane adhesives that incorporate proteins from industrial byproducts. The investigation involved three protein sources: soybean meal, shrimp shells, and skim milk, modified under mild alkaline conditions to obtain protein concentrates. These concentrates were then incorporated into the adhesives at varying protein contents: 5%, 10%, and 15%. Additionally, two isocyanate systems were examined, one being petrochemical-based and the other a partially bio-based blend. Chemical, thermal, optical, and mechanical characterizations were conducted to evaluate the adhesive performance. This study demonstrates that the adhesives’ thermal properties remain unaffected by both the protein content and the isocyanate system. However, these factors influence the adhesive penetration into the wood substrate. Ultimately, the results suggest that higher protein content offers superior retention of mechanical strength in adhesives compared to the petrochemical reference when subjected to humid conditions. Overall, this research demonstrates the potential of proteins from industrial byproducts as sustainable adhesive allies, providing valuable insights into their interactions with different isocyanates.

Exploring the antifungal potential of Annona muricata leaf extract-loaded hydrogel in treating vulvovaginal candidiasis

Vulvovaginal candidiasis, mostly caused by Candida albicans, remains a prevalent concern in women's health. Annona muricata L. (Annonaceae), a plant native from Brazil, is well-known for its therapeutic potential, including antitumor, anti-inflammatory, and antimicrobial properties. This study presents an innovative hydrogel formulation containing the ethanolic extract from A. muricata leaves designed to control C. albicans in an in vivo model of vulvovaginal candidiasis. Here, we report the development, thermal, physicochemical and rheological characterization of a Carbopol®-based hydrogel containing A. muricata extract. Furthermore, we evaluated its activity in a vulvovaginal candidiasis in vivo model. Thermal analyses indicated that the addition of the extract increased the polymer-polymer and polymer-solvent interactions.Rheological analysis showed a decrease in the viscosity and elasticity of the formulation as the A. muricata extract concentration increased, suggesting a liquid-like behavior. After treatment with the Carbopol®-based hydrogel with A. muricata, our in vivo results showed a significant reduction in vulvovaginal fungal burden and infection, as well as a reduction in mucosal inflammation. The current research opens up possibilities for the application of the Carbopol®-based hydrogel with A. muricata as a natural therapeutic option for the treatment of vulvovaginal candidiasis.

Olive stone as a filler for recycled high-density polyethylene: A promising valorization of solid wastes from olive oil industry

The valorization of solid residues generated from olive oil production is a challenging issue for olive oil-producing countries such as Greece, Italy, Spain, etc. Olive stone waste is a type of lignocellulosic biomass with potential use as a natural additive in polymeric composites. In the present study, olive stone waste was compounded with recycled high-density polyethylene (rHDPE) via melt mixing in 5 %, 10 %, and 20 % wt. Additionally, the effect of Joncryl (JC) and polyethylene-grafted maleic anhydride (PE-g-MA) as compatibilizers on the properties of the green composites was also investigated. It is worth mentioning that JC was employed for the first time as a compatibilizer for polyolefin composites with olive stone. The materials underwent structural, thermal, and mechanical characterization using multiple complementary techniques. Scanning electron microscopy showed good dispersion of the filler for all composites, while in the compatibilized samples a markedly better adhesion was observed. Tensile tests revealed an increase in the elastic modulus for the composite with 10 % wt. olive stone. Furthermore, all materials demonstrated a strong antioxidant activity, rendering them interesting for active packaging applications. Overall, the solid residue from olive processing can enhance the properties of rHDPE, paving the way to promote circular economy.