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This work examines theoretical and experimental aspects concerning the thermal characteristics of components fabricated via the fused deposition modeling (FDM) technique utilizing conductive ABS and PLA polymers. It use inverse problems to accomplish this. An infrared thermographic camera assessed the temperature and facilitated heat flow between the plates to acquire experimental data. We developed the mathematical model for addressing the direct problem based on transient heat conduction and formulated the inverse problem to ascertain a set of optimal parameters utilizing stochastic approaches. We devised a computer algorithm to ascertain the specific heat capacity and thermal conductivity of diverse infill patterns, then corroborated the method utilizing materials with established attributes. The wiggle infill design produced the highest specific heat capacity values for ABS-graphene, whereas the grid infill pattern was excellent for PLA-graphene. The triangular infill pattern for ABS-graphene and the rectilinear infill pattern for PLA-graphene produced the optimal thermal conductivity values. This work emphasizes the significance of comprehending and employing inverse problem techniques in the thermal characterization of anisotropic materials, including the conductive polymers utilized in the FDM process. [ABSTRACT FROM AUTHOR]

Fiber-reinforced polymers are crucial for insulating electrical equipment, necessitating accurate thermal property data for an effective thermal analysis. This case study uses a cost-effective method to thermally characterize a glass fiber-reinforced epoxy resin used in air-core reactor insulation. The approach simultaneously estimates temperature-dependent thermal conductivity (k) and specific heat (cp) for class H/180 insulation. By analyzing transient heat conduction in a 3D composite sample under vacuum and at various temperatures, the method optimizes sensor placement, enabling accurate property estimation with a single thermocouple. The estimated through-thickness thermal conductivity at room temperature deviates by less than 6% from standard guarded hot plate measurements. The method's reliability is confirmed by accurately retrieving the applied heat flux using the estimated properties and measured temperature data. The results are valuable for designing accurate simulation models to predict and manage the thermal behavior of air-core reactors, as implemented by GE Grid Solutions in Itajubá, Brazil. [ABSTRACT FROM AUTHOR]

Inverse problems are commonly used in many fields as they enable the estimation of parameters that cannot be experimentally measured. However, the complex nature of inverse problems requires a strong background in data and signal processing. Moreover, ill-posed problems yield parameters that have a strong linear dependence on the problem. The ill-posed nature of these problems lead to many errors in numerical computations that can make parameter identification nearly impossible. In this paper, a new data processing tool is proposed to maximize the sensitivity of the model to the parameters of interest, while reducing the correlation between them. The effectiveness of the toll is demonstrated through a given inverse problem example using Periodically Pulsed Photothermal Radiometry (PPTR). [ABSTRACT FROM AUTHOR]

Plaited jersey fabrics are always engineered to enhance the thermal conductivity characteristics, providing thermal equilibrium among the wearer and clothing during hot weather. These can also be architected with higher thermal resistance/heat insulation characteristics and is a crucial area of interest; however there isn't any significant literature reporting this. The study focuses on developing plaited jersey gloves using Thermolite®, acrylic, and wool yarns in alternative main and plaiting configurations for winterwear. Thermal characterizations were conducted to ascertain heat and mass transfer properties, such as fluid transmission and thermal resistance. Infrared (IR) imaging visualized heat retention in terms of temperature gradients. Mechanical characteristics, such as pilling and bursting, were assessed to determine the gloves durability to physical abrasions and stresses. Thermolite® knitted gloves possessed superior heat and mass transfer properties with improved fluid transmission and thermal resistance. Infrared imaging revealed highest body temperature rise of 34.43oC for Thermolite®, and mechanical properties were also found adequate. Fluid transfer (air permeability) was acquired highest for wool samples (1770 mm/sec); however, Thermolite® exhibited 28% lower air permeability than wool, validating its heat retention. Thermolite® knits with the lowest areal density of 226 g/m2 and the smoothest Thermolite® surface had the highest OMMC (overall moisture management capacity) index of 0.46 due to generated capillaries. The statistical analysis of the characterization data indicated the significance (p -value <0.05) of the main and plating yarns, proving the plaiting a solution to achieve desired heat and mass transfer characteristics. [ABSTRACT FROM AUTHOR]

New nitrobenzyl-pyridyl ether ligands were synthesized by reacting nitrobenzyl bromide (2-, 3- and 4-nitro) and halogen-substituted hydroxy pyridine (2-chloro-3-hydroxy-pyridine, 2-bromo-3-hydroxy-pyridine) compounds in DMF. By interacting the obtained ligands (L1, L3, L4 and L6) with silver (I) nitrate, transition metal complexes were prepared (AgL1, AgL3, AgL4 and AgL6). The structures of the synthesized ligands and complexes were characterized using FTIR, HRMS, 1H-NMR and 13C-NMR spectroscopic techniques. In addition, fluorescence spectra of the ligands (L1-L6) were detected in the presence of different metal cations (Li+, Na+, Mg2+, Al3+, K+, Ca2+, Cr3+, Fe3+, Co2+, Ni2+, Cu2+, Zn2+ and Ag+). In addition, the thermal behavior of all compounds were examined by TGA-DTA methods and the data of silver complexes and ligands were compared. Within the scope of the study, the antibacterial activities of all compounds were investigated against 4 pathogens, 2 of which were plant-borne (Xanthomonas vesicotoria, Clavibacter michiganensis subsp. Michiganensis) and 2 were food-borne (Escherichia coli, Listeria monocytogenes). [ABSTRACT FROM AUTHOR]

The demand for materials with specific properties continues to grow in modern industry, necessitating a deeper understanding of metal solidification processes. This study investigates the thermal and microstructural characteristics of a novel multicomponent alloy, Al33wt%Cu1wt%Ni-1.2wt%Ta, which has not been previously reported in the literature. This alloy, comprising aluminum, copper, nickel and tantalum, exhibits superior mechanical strength, thermal stability and corrosion resistance compared to conventional alloys, making it suitable for various applications. Utilizing transient heat flow techniques, thermal characterization and microstructural analysis were performed on the alloy after solidification. Thermal mapping revealed variable growth and cooling rates along the ingot, influencing macrostructural transitions from columnar to equiaxed grains. Microstructural examination uncovered a complex evolution, with refined dendritic spacings initially, followed by the formation of intermetallic phases such as Al3Ta, α-Al and Al2Cu. The study also proposed a hypothesis on the formation of diamond-shaped intermetallics like Ni3Ta and Ta(Cu,Al)2, which were consumed to form Al7Cu4Ni at the edges. Secondary dendritic spacing analysis supported this hypothesis, showing correlation with growth laws. The findings provide valuable insights into solidification behavior and microstructural evolution, aiding in parameter optimization and enhancing the alloy's properties for specific applications. However, limitations include the need for further research to explore mechanical and thermal properties and validate industrial potential. [ABSTRACT FROM AUTHOR]

Dielectric barrier discharge plasma actuators have recently become desirable devices for simultaneous flow control and ice mitigation applications, with particular interest in wind turbines operating in cold climates. Considering the potential of plasma actuators for these specific applications, it is necessary to deeply understand the thermal effects generated by the plasma-induced flow to proceed with further optimizations. However, due to the local high electric field and high electromagnetic interference generated, there is a lack of experimental studies on the topic. The current work implements an in-house experimental technique based on the background-oriented schlieren principle for plasma-induced flow thermal characterization. Since this technique is based on optical measurements, it is not affected by the electromagnetic interference issues caused by the plasma discharge. A detailed experimental analysis is performed on a conventional Kapton actuator exploiting the relation between the actuator surface temperature and the induced thermal flow. The influence of the input voltage and the transient plasma-induced flow thermal behavior is analyzed. The results demonstrate that plasma actuators are fast response time devices that can heat the adjacent medium in less than a second after starting the operation. [ABSTRACT FROM AUTHOR]

Shape-memory polymers (SMPs) possess unique properties that respond to external stimuli. The current review discusses types of SMPs, fabrication methods, and the characterization of their mechanical, thermal, and shape recovery properties. Research suggests that SMP composites, when infused with fillers, demonstrate enhanced mechanical and thermal characteristics. On the other hand, blends, particularly incorporating polylactic acid (PLA), exhibit the most efficient shape recovery. Furthermore, the crosslinking density in polymer blends impacts the shape recovery force, showcasing a correlation between energy storage capacity and shape recovery force in SMP networks. Overall, SMP blends show promising mechanical, thermal, and shape recovery features, rendering them advantageous for applications of artificial muscles, soft actuators, and biomedical devices. This review also discusses the future prospectives of SMP for robust applications. [ABSTRACT FROM AUTHOR]

Wool is a popular natural animal fiber that has been used for many years and contributes significantly to the economies of various producing countries and manufacturers. In recent years, the share of wool continues to decline from a source of income for farmers to a waste product, as a result of different production challenges and livestock issues. The main aim of this article is to investigate the physicochemical properties of the various types of Moroccan wool before and after degreasing process in order to initiate the development of ecological and technical textile products. For this purpose, different types of Moroccan wool were collected, studied, characterized, and compared in terms of thermophysical properties using a range of techniques including infrared spectroscopy (FTIR), microscopic analysis, thermogravimetric analysis, and differential scanning calorimetry. In addition, diameter, color and crimp rate, moisture, and fat content were measured and discussed. The morphological and structural characterization ensured that the studied fibers were almost identical with a difference in diameter ranging from 8.02 to 19.48 μm; the removal of fat and impurities improved the quality of the wool surface by making the functional groups of keratin more exposed and reactive. The thermal results showed that the thermal behavior is directly influenced by the physical properties of the wool fiber such as fat and moisture content. The degreased fibers exhibit a slight shift related to the action of the chemical compound; moreover, the transition related to the denaturation process of the keratin chain is more significant. The results also showed that the degreasing treatment causes a significant color change in the wool fibers by increasing the brightness coordinates and negatively influences the crimp rate and moisture content. The findings of the study revealed that the different breeds available in Morocco retain their importance for use in various technical textiles. [ABSTRACT FROM AUTHOR]

Sodium alginate (SA) hydrogels with an addition of graphene oxide (GO) and hydroxyapatite (HAp) crosslinked by calcium chloride solution were investigated as potential materials for osteochondral tissue regeneration. The influence of various ratios of the nanoadditives in the natural derived polymer matrix on the thermal, physiochemical and biological properties was studied. Two thermal characterization methods (DSC and TGA) were employed to examine the thermal properties of the materials and provide information regarding the different types of water within the hydrogel structure. These parameters are crucial for the assessing and understanding of the adsorption/desorption processes in hydrogels and also impact their biocompatibility. The effect of GO and HAp addition on thermal characteristics of alginate hydrogel is reported, as well as the nanoadditives polymer chains interaction, as evidenced by FTIR results. The compression test confirmed that the nanoadditives, uniformly dispersed in the polymer matrix, improved the mechanical properties of the hydrogels, but only up to a certain content of additives. The composite hydrogels exhibited a very low friction coefficient. Both GO and HAp also enhanced chemical stability of alginate hydrogels under in vitro conditions. Biological assays demonstrated that most of the tested hydrogel extracts were not cytotoxic to hUC-MSCs, but they can affect the proliferation rate of the cells. Developed materials may present an intriguing alternative for osteochondral tissue regeneration. [ABSTRACT FROM AUTHOR]

Animal droppings are a source of severe environmental and health problems if not well managed. The goal of this study is to evaluate the energy potential of animal droppings from the Adamawa region of Cameroon and to predict suitable thermal conversion technologies. Structural, proximate analyses, and higher heating value (HHV) were determined experimentally, while ultimate analysis, higher heating value and flue gases were modeled from structural and proximate analyses. This study reveals that animal droppings are estimated at 3,292 972 tons of dry bone per year with cattle droppings being the most dominant. Their theoretical energy potential ranges from 48GJ/year to 58GJ/year against 46GJ/year for the experimental energy potential of combustion energy. The average absolute errors (AAE) are 4% and 6% for energy potential from ultimate and proximate analyses, respectively. These AAE are negligible and can justify the reliability of theoretical estimation of energy potential from proximate and ultimate analyses. Results also showed that flue gas released does not have a negative impact on the environment as the values are within admissible limits, and the pollutant emissions are below the regulated threshold values. The animal droppings properties studied show that they can be efficiently used in thermal conversion processes such as pyrolysis, gasification, and biogas as well as catalysts in the thermal conversion technologies. This could produce 7.81 × 108 Nm3/year and 7.70 × 105 m3/year, for annual syngas and methane, respectively. Nevertheless, the levels of S and N could be taken into account in the design of a gasification plant to control the emission of NO2 and SOx-derived pollutants as their values are more than 0.2% and 0.6%, respectively. These droppings can be used as alternative energy sources as they are highly available and can improve environmental sustainability. [ABSTRACT FROM AUTHOR]

In the present work, glass samples in the (100 − x)B2O3–xLi2O binary system, with x varying from 30 to 50 mol%, were prepared using the conventional melting and moulding method, with the main objective of evaluating the thermoluminescence response when exposing these materials to ultraviolet (UV) radiation. Complementary analysis based on density, optical absorption on the UV–visible region (UV–vis absorbance), Fourier transform infrared spectroscopy on the medium region, X‐ray diffraction, and differential thermal analysis measurements were performed. Thermoluminescence measurements of vitreous samples showed glow curves with at least one peak with a maximum temperature of ~170°C after exposure to UV radiation in the temperature range 50–250°C. Samples were also exposed to beta radiation in the temperature range 25–275°C, also showing single peaks with a maximum temperature of ~150°C. [ABSTRACT FROM AUTHOR]

Condom industry waste mainly consists of light magnesium carbonate (LMC), which is extensively used as a finishing powder during the final stages of condom production. This LMC waste (LW) is usually disposed of as a landfill, causing an increase in the hardness of water. LW generated in HLL Lifecare Limited, India, was procured, characterized by analytical techniques, and reutilized in natural rubber (NR) as a reinforcing filler. The prepared composites were subjected to rheological, mechanical, thermal and sorption characterizations. In comparison to NR neat, the composite with 3 phr (parts per hundred of rubber) LW showed a rise in tensile strength, tear strength, and modulus at 300% elongation by 22%, 20%, and 28%, respectively. A remarkable decrease in abrasion loss is also evidenced. The activation energy (Ea) for degradation, calculated by the Coats-Redfern (CR) method, showed 10 kJmol-1 increase for composite with 3 phr LW, proving its better thermal stability. It also exhibited higher solvent uptake resistance, as established by sorption experiments. The superior properties of this composite have been attributed to the uniform LW distribution and ameliorated NR-LW interaction. Hence, the prepared composites find considerable potential in manufacturing industrial NR components accomplishing a circular economy. [ABSTRACT FROM AUTHOR]

Thermal energy storage (TES) systems use solar energy despite its irregular availability and day-night temperature difference. Current work reports the thermal characterizations of solar salt-based phase change composites in the presence of graphene nanoplatelets (GNP). Solar salt (60:40 of NaNO3:KNO3) possessing phase transition temperature and melting enthalpy of 221.01°C and 134.58 kJ/kg is proposed as a phase change material (PCM) for high-temperature solar-based energy storage applications. Thermal conductivity must be improved to make them suitable for widespread applications and to close the gap between the system needs where they are employed. GNP is added at weight concentrations of 0.1%, 0.3%, and 0.5% with solar salt using the ball milling method to boost its thermal conductivity. Morphological studies indicated the formation of a uniform surface of GNP on solar salt. FTIR spectrum peaks identified the physical interaction between salt and GNP. Thermal characterization of the composites, such as thermal conductivity, DSC and TGA was carried out for the samples earlier and later 300 thermal cycles. 0.5% of GNP has improved the thermal conductivity of salt by 129.67% and after thermal cycling, the enhancement reduced to 125.21% indicating that thermal cycling has a minor impact on thermal conductivity. Phase change temperature decreased by around 2.32% in the presence of 0.5% GNP and the latent heat reduced by 4.34% after thermal cycling. TGA thermograms depicted the composites initiated the weight loss at around 550°C after which it was rapid. After thermal cycling, the weight loss initiated at ∼40°C lower compared to pure salt, which was found to be a minor change. Thermal characterization of solar salt and GNP-based solar salt composites revealed that the composites can be used for enhanced heat transfer in high-temperature solar-based heat transfer and energy storage applications. [ABSTRACT FROM AUTHOR]

The present study focuses on correlations between three parameters: (1) graphite particle size, (2) the ratio of graphite to oxidizing agent (KMnO4), and (3) the ratio of graphite to acid (H2SO4 and H3PO4), with the reaction yield, structure, and properties of graphene oxide (GO). The correlations are a challenge, as these three parameters can hardly be separated from each other due to the variations in the viscosity of the system. The larger the graphite particles, the higher the viscosity of GO. Decreasing the ratio of graphite to KMnO4 from 1:4 to 1:6 generally leads to a higher degree of oxidation and a higher reaction yield. However, the differences are very small. Increasing the graphite-to-acid-volume ratio from 1 g/60 mL to 1 g/80 mL, except for the smallest particles, reduced the degree of oxidation and slightly reduced the reaction yield. However, the reaction yield mainly depends on the extent of purification of GO by water, not on the reaction conditions. The large differences in the thermal decomposition of GO are mainly due to the bulk particle size and less to other parameters. [ABSTRACT FROM AUTHOR]

In this research work, the suitability of short carbon fibre-reinforced polyamide 6 in pellet form for printing an aeronautical mould preform with specific thermomechanical requirements is investigated. This research study is based on an extensive experimental characterization campaign, in which the principal mechanical properties of the printed material are determined. Furthermore, the temperature dependency of the material properties is characterized by testing samples at different temperatures for bead printing and stacking directions. Additionally, the thermal properties of the material are characterized, including the coefficient of thermal expansion. Moreover, the influence of printing machine parameters is evaluated by comparing the obtained tensile moduli and strengths of several manufactured samples at room temperature. The results show that the moduli and strengths can vary from 78% to 112% and from 55% to 87%, respectively. Based on a real case study of its aeronautical use and on the experimental data from the characterization stage, a new mould design is iteratively developed with multiphysics computational guidance, considering 3D printing features and limitations. Specific design drivers are identified from the observed material's thermomechanical performance. The designed mould, whose mass is reduced around 90% in comparison to that of the original invar design, is numerically proven to fulfil thermal and mechanical requirements with a high performance. [ABSTRACT FROM AUTHOR]

Abstract This paper investigates evidence regarding the influence of a CaSt2 residual additive in the optical properties of a commercial polystyrene. This work proposes an in-line optical detector operating by illuminating the polymer with a red monochromatic light in order to evaluate its thermal behavior during a heat cycling. The detection system was bench validated by measuring the light absorption of aqueous solutions of organic acid dyes. The system showed great sensitivity in detecting the contamination’s effect on the polymer, as a great impact on the polymer’s behavior was observed due to the presence of the additive during different thermal cycles. The detector system showed that the salt’s presence elevates absorbance by five times when the temperature is higher than its fusion temperature. The in-line optical detector has proved to be suitable to quantify the presence of additives that affects the polymer’s optical properties.

Phase-change materials (PCMs) can be used to develop thermal energy storage systems as they absorb large amount of latent heat nearly at a constant temperature when changing phase from a solid to a liquid. To prevent leakage when in a liquid state, PCM is shape stabilized in a polymer matrix of high-density polyethylene (HDPE). The present research explores the injection-molded mechanical and thermal properties of different PCM/HDPE composite ratios. The tensile strength and modulus of elasticity at room temperature and with the PCM fully melted within the composite are measured. Additionally, the hardness, latent heat of fusion, phase-change temperature, and thermal conductivity are investigated. An analysis of microstructures of the composite is used to support the findings. The PCM within the PCM/HDPE composite gives it the benefit of thermal storage but causes a decrease in mechanical properties. [ABSTRACT FROM AUTHOR]

This study is devoted to characterization of the Glycyrrhiza glabra (licorice root) fibers (GGFs) that have different uses in industrial areas, globally. For this purpose, several properties of GGFs were investigated to determine their suitability for natural fiber-reinforced composite production. Such properties include; physical, chemical, thermal, morphological, X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy, as well. As a result of these analyses, it was found that the GGFs are composed of cellulose (40.46%), hemicellulose (15.94%), lignin (12%), waxes (1.3%), moisture (9.93%), and others. The density of GGFs was measured as 1.43 g/cm3. Additionally, the existence of cellulose with a 35.86% crystal index, was also verified by the XRD characterization results of these fibers. The thermogravimetric analysis (TGA) results showed that GGFs are thermally stable within the polymerization process temperature of 354.09°C. As a result, it was determined that GGFs have characteristics with significant potential as cellulose-based reinforcement fiber for industrial applications. [ABSTRACT FROM AUTHOR]

Natural fiber reinforced polymeric composites perform poor in mechanical and thermal properties at elevated temperatures due to the cellulose and hemicellulose contents of natural fiber start degrading at elevated temperature. In this research work, flame retardancy and thermal stability of treated and untreated kenaf fiber reinforced epoxy composites have been experimentally investigated and reported. Two composite laminates, one with 6 % NaOH Alkali treated and another with untreated woven kenaf mats, were fabricated by hand lay-up technique followed by compression molding with 40 % fiber weight fractions. Flame retardancy test and various thermal characteristics studies such as thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), heat deflection temperature (HDT), and morphological analysis via scanning electron microscopy (SEM) tests were carried out. The results showed that alkali treated kenaf fiber composite achieved V0 fire retardancy grade. The major weight losses, 86 % and 75.5 % for untreated and treated composites respectively were recorded between 300 °C and 450 °C. 13.6 % increase in HDT was noted for treated composite with 0.25 mm deflection at 0.45 MPa pressure condition. Thus the composite laminate with 6 % NaOH alkali-treated kenaf fiber achieved the best thermal stability with less degradation which is more suitable for automobile and aerospace applications. [ABSTRACT FROM AUTHOR]

An engineering approach for thermal characterization of an interior permanent magnet electric motor (EM) with a specific aim to identify the interdependency between its mean coil temperature and the maximum component temperatures at the conditions with constant and variable loads/speeds is proposed. For specifying the convective thermal boundary condition between stator and rotor that spins at variable speeds/directions, an experimental study aimed at devising the empirical heat transfer correlation for the Taylor-Couette airflow with varying rotating speed/direction is performed. It is firstly revealed that the responsive air-gap heat convection to angular acceleration follows the characteristic of a single-degree-of-freedom (SDOF) dynamic system. Along with the heat transfer correlation for the unsteady Taylor-Couette airflow, the nonhomogeneous thermal conductivity model that considers the orthogonality effect of the bent coiled winding at its two axial ends is integrated with an iteration scheme for calculating the air bulk temperature in an entrapped air chamber. The favorable experimental validation with the maximum discrepancies between predicted and measured component temperatures less than 7 % in steady and unsteady running conditions affirms the accuracy of the proposed simulation model. At a rotating speed of 4800 rev/min and power output of 1688 W, the maximum-to-mean temperature differences of stator winding, magnetic stripe, and steel sheet of stator reach respectively 6.75 °C, 3.21 °C, and 6.94 °C. Particularly, all the maximum component temperatures are well correlative with the mean temperature of the stator winding at the various steady/unsteady operating conditions. This finding extends the application of lumped thermal network analysis that predicts the averaged components’ temperatures; and enables the on-line monitoring for the maximum component temperatures using a mean stator-winding temperature as the controlling factor.

A novel semi-organic crystal has been grown using slow evaporation technique by doping organic compound L-asparagine monohydrate (C4H8N2O3·H2O) with inorganic material Magnesium sulphate heptahydrate (MgSO4·7H2O). The crystallographic parameters like strain, dislocation density and crystallite size were calculated by powder X-ray diffraction method. Functional groups were identified and bond length, force constants were calculated from FT-IR spectroscopy. Energy dispersive X-ray (EDX) analysis was used to identify the constituent elements of the crystal. Kinetic and thermodynamic parameters, such as, activation energy Ea, change in Gibb's free energy (ΔG) and change in enthalpy (ΔH) have been determined by thermogravimetric analysis (TGA) analysis. Ea, ΔH and ΔG show positive values and change in entropy (ΔS) shows negative ones. The thermal degradation behavior of the crystals has been analyzed by differential scanning calorimetry (DSC) analysis. Various optical constants such as optical band gap, lattice dielectric constant, absorbance, extinction coefficient, the ratio of free charge carrier concentration to the effective mass, Urbach energy, optical and electrical conductivities were estimated from UV–vis transmittance data. High optical conductivity (1010 s−1) justifies the good photo response nature of the semi-organic crystal.

Bio-based epoxy thermoset resins have been developed from epoxidized soybean oil (ESO) cured with tannic acid (TA). These two substances of vegetable origin have been gathering attention due to their accessibility, favorable economic conditions, and convenient chemical functionalization. TA's suitable high phenolic functionalization has been used to crosslink ESO by adjusting the −OH (from TA):epoxy (from ESO) molar ratio from 0.5:1 to 2.5:1. By means of Fourier-transform infrared spectroscopy, resulting in thermosets that evidenced optimal curing properties under moderate conditions (150–160 °C). The thermogravimetric analysis of the cured resins showed thermal stability up to 261 °C, with modulable mechanical and thermal properties determined by differential scanning calorimetry, dynamical mechanical thermal analysis, and tensile testing. Water contact angle measurements (83–87°) and water absorption tests (0.6–4.5 initial weight% intake) were performed to assess the suitability of the resins as waterproof coatings. Electrochemical impedance spectroscopy measurements were performed to characterize the anti-corrosive capability of these coatings on carbon steel substrates. Excellent barrier properties have been demonstrated due to the high electrical isolation and water impermeability of these oil-based coatings, without signs of deterioration over 6 months of immersion in a 3.5 wt.% NaCl solution. These results demonstrate the suitability of the developed materials as anti-corrosion coatings for specific applications. [ABSTRACT FROM AUTHOR]

In recent years, there has been a growing interest in effectively managing agro-industrial waste. One promising approach that has gained attention is exploring this waste to develop new composite materials, especially polymeric materials, with diverse applications across various industries. This study focuses on comprehending the physical and thermal properties of fibrous residues derived from achira (Canna edulis Ker). To achieve this, several analyses, including thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and Fourier transform infrared spectrometry (FTIR), have been conducted. Additionally, parameters such as moisture percentage, moisture absorption, bulk density, and lignin percentage have been calculated. The results indicate similarities between achira fibers and other characterized fibers, such as bamboo and other natural fibers studied in scientific research. Based on these findings, it is evident that integrating achira fibers into polymeric matrices is a feasible option. The results of this research offer an opportunity to utilize these materials and contribute to the advancement and strengthening of the recycled raw materials market, promoting sustainability and the circular economy. [ABSTRACT FROM AUTHOR]

The paper presents the synthesis and thermal behavior of novel epoxy resins prepared from epoxidized castor oil in the presence of or without trimethylolpropane triglycidyl ether (TMP) crosslinked with 3-hexahydro-4-methylphtalic anhydride (MHHPA) and their comparison with a petroleum-based epoxy resin (MHHPA and TMP). Epoxidized castor oil (ECO) was obtained via in situ epoxidation of castor oil with peroxyacetic acid. The chemical structures of castor oil (CO), ECO, and epoxy matrix were confirmed using FT-IR and 1H-NMR spectroscopy. The morphological and thermal behavior of the resulting products have been investigated. Compared to petroleum-based resins, castor oil-based ones have a lower Tg. Anyway, the introduction of TMP increases the Tg of the resins containing ECO. The morphological behavior is not significantly influenced by using ECO or by adding TMP in the synthesis of resins. The dielectric properties of epoxy resins have been analyzed as a function of frequency (1 kHz–1 MHz) and temperature (−50 to 200 °C). The water absorption test showed that as Tg increased, the percent mass of water ingress decreased. [ABSTRACT FROM AUTHOR]

Nickel-based superalloys are widely employed to manufacture aero-engine turbines due to their high mechanical strength and resistance to corrosion and creep. Vacuum Induction Melting (VIM) is a suitable manufacturing technology because of the reactive nature of the alloying elements; however, the melting process is time-consuming and energy-demanding. This research focuses on increasing the overall efficiency of the process in two ways. Initially, studying the influence of metal-containing crucible composition and thermal properties on the melting. In a semi-industrial VIM facility, 2 kg of Inconel 718 alloy was melted employing Al2O3, ZrO2, MgO, and Al6Si4O13-based crucibles. The Al6Si4O13 and ZrO2-based crucibles reduced energy consumption by 28% and 23%, respectively, compared to the reference crucible of Al2O3. Subsequently, an optimized melting procedure is proposed to reduce the process cycle time and energy demand, saving 10%–20% for all crucibles compared to the standard melting procedure. In addition, the ZrO2 and Al6Si4O13 crucibles reduced total cycle time by 13% and 21%, respectively. During melting, intense dross formation was detected for all crucibles, dissipating faster for Al6Si4O13 and MgO crucibles. Therefore, the metal-crucible interface product was analyzed to understand these mechanisms better, and the four crucibles' chemical reactivity was examined.

The stem bark of Acacia caesia, or Senegalia caesia, richly available in the Western Ghats of Tamilnadu and Kerala, India, does potentially offer a ligno-cellulosic fiber, which was characterized in this work, studying its chemical composition, morphology, and thermal degradation. The as-received fibers, which were extracted as technical fibers with diameters ranging between 100 and 150 µm, had a density of 1200 kg/m3. Their composition included 37% cellulose, 20% hemicellulose and 18% lignin, not very dissimilar, among other fibers, from alfa esparto and particularly coir. Their thermal degradation onset was at 308°C, which suggested a potential in composite application with traditional oil-based matrices and possibly also in the long run on bio-based ones. However, their high roughness and easy splitting of the fibers suggested that possible use as the filler for composites would require fiber treatment, namely, to remove undesired loose parts, hence regularizing their geometry. This would also serve to reduce the likeliness of longitudinal splitting, which is a widely recognized occurrence during stripping of bark fibers.

In this investigation, an automotive component made of nylon as a structural element was studied by several characterization techniques to identify material properties. Firstly, a Fourier transform infrared spectroscopy (FTIR) was carried out to obtain information about composition, then, differential scanning calorimetry (DSC) was used to extract useful information on sample thermal behavior. The humidity and volatile materials percentage could be assessed by thermogravimetry analysis (TGA). Morphology and topography were carried out by optical microscopy, moreover, X-ray Tomography allows it to display the sample's inner part. Characterization shows that the component could have been contaminated or exposed to conditions that promote degradation after the manufacturing process. Finally, computerized X-ray tomography displayed that both samples showed a difference in porosity in a fractured sample and a healthy sample. All the above implies a change in the mechanical integrity of the fractured material but might not omit the fact that it could have been subjected to any type of impact or mechanical effort. [ABSTRACT FROM AUTHOR]

Poly(p-xylylene) derivatives, widely known as Parylenes, have been considerably adopted by the scientific community for several applications, ranging from simple passive coatings to active device components. Here, we explore the thermal, structural, and electrical properties of Parylene C, and further present a variety of electronic devices featuring this polymer: transistors, capacitors, and digital microfluidic (DMF) devices. We evaluate transistors produced with Parylene C as a dielectric, substrate, and encapsulation layer, either semitransparent or fully transparent. Such transistors exhibit steep transfer curves and subthreshold slopes of 0.26 V/dec, negligible gate leak currents, and fair mobilities. Furthermore, we characterize MIM (metal–insulator–metal) structures with Parylene C as a dielectric and demonstrate the functionality of the polymer deposited in single and double layers under temperature and AC signal stimuli, mimicking the DMF stimuli. Applying temperature generally leads to a decrease in the capacitance of the dielectric layer, whereas applying an AC signal leads to an increase in said capacitance for double-layered Parylene C only. By applying the two stimuli, the capacitance seems to suffer from a balanced influence of both the separated stimuli. Lastly, we demonstrate that DMF devices with double-layered Parylene C allow for faster droplet motion and enable long nucleic acid amplification reactions. [ABSTRACT FROM AUTHOR]

In this research work, the suitability of short carbon fibre-reinforced polyamide 6 in pellet form for printing an aeronautical mould preform with specific thermomechanical requirements is investigated. This research study is based on an extensive experimental characterization campaign, in which the principal mechanical properties of the printed material are determined. Furthermore, the temperature dependency of the material properties is characterized by testing samples at different temperatures for bead printing and stacking directions. Additionally, the thermal properties of the material are characterized, including the coefficient of thermal expansion. Moreover, the influence of printing machine parameters is evaluated by comparing the obtained tensile moduli and strengths of several manufactured samples at room temperature. The results show that the moduli and strengths can vary from 78% to 112% and from 55% to 87%, respectively. Based on a real case study of its aeronautical use and on the experimental data from the characterization stage, a new mould design is iteratively developed with multiphysics computational guidance, considering 3D printing features and limitations. Specific design drivers are identified from the observed material’s thermomechanical performance. The designed mould, whose mass is reduced around 90% in comparison to that of the original invar design, is numerically proven to fulfil thermal and mechanical requirements with a high performance.

The paper aims to compare different methods able to estimate the specific loss power (SLP) generated by three different types of magnetic nanoparticles, MNPs, dispersed in a suspension fluid, e.g., octane or water. The nanoparticles were characterized morphologically in terms of shape and size, chemically for composition and their physical properties like magnetization and SLP were studied. We evidenced the differences in SLP evaluation due to the applied method, particularly in the presence of thermally induced phenomena such as aggregation or precipitation of MNPs that can affect the heating curve of the samples. Then, the SLP determination methods less sensible to this phenomenon appear to be the ones that use the initial slope when the sample is in quasi-adiabatic condition. Finally, we propose a comparison of those methods based on the pros and cons of their use for the SLP determination of magnetic nanofluids. In particular, the analysis of the behavior of the heating curve is useful to evaluate the useful amplitude of the interval analysis for the initial slope methods. [ABSTRACT FROM AUTHOR]

Type-1 diabetes is one of the most prevalent metabolic disorders worldwide. It results in a significant lack of insulin production by the pancreas and the ensuing hyperglycemia, which needs to be regulated through a tailored administration of insulin throughout the day. Recent studies have shown great advancements in developing an implantable artificial pancreas. However, some improvements are still required, including the optimal biomaterials and technologies to produce the implantable insulin reservoir. Here, we discuss the employment of two types of cyclic olefin copolymers (Topas 5013L-10 and Topas 8007S-04) for an insulin reservoir fabrication. After a preliminary thermomechanical analysis, Topas 8007S-04 was selected as the best material to fabricate a 3D-printed insulin reservoir due to its higher strength and lower glass transition temperature (Tg). Fiber deposition modeling was used to manufacture a reservoir-like structure, which was employed to assess the ability of the material to prevent insulin aggregation. Although the surface texture presents a localized roughness, the ultraviolet analysis did not detect any significant insulin aggregation over a timeframe of 14 days. These interesting results make Topas 8007S-04 cyclic olefin copolymer a potential candidate biomaterial for fabricating structural components in an implantable artificial pancreas. [ABSTRACT FROM AUTHOR]

A computational methodology based on supervised machine learning (ML) is described for characterizing and designing anisotropic refractory composite alloys with desired thermal conductivities (TCs). The structural design variables are parameters of our fast computational microstructure generator, which were linked to the physical properties. Based on the Sobol sequence, a sufficiently large dataset of artificial microstructures with a fixed volume fraction (VF) was created. The TCs were calculated using our previously developed fast Fourier transform (FFT) homogenization approach. The resulting dataset was used to train our optimal autoencoder, establishing the intricate links between the material's structure and properties. Specifically, the trained ML model's inverse design of tungsten-30% (VF) copper with desired TCs was investigated. According to our case studies, our computational model accurately predicts TCs based on two perpendicular cut-section images of the experimental microstructures. The approach can be expanded to the robust inverse design of other material systems based on the target TCs. [ABSTRACT FROM AUTHOR]

The characterization of the thermal properties of polymers represents a fundamental step in improving materials for energy harvesting processes. Thermal conductivity, for example, is measured by measuring heat flux and temperature difference. This study seeks to design and fabricate an experimental set‐up to measure the thermal conductivity of low‐thickness polymers at room temperature. It is unique in that it is an affordable and lightweight instrument developed using electrical resistance as a heater and a limited number of components. Error analysis and reproducibility analysis were carried out for the thermal conductivity. The instrument was found to be reliable in making thermal conductivity measurements with an average of ±7%. [ABSTRACT FROM AUTHOR]

This study investigated the effects of ultrasonic and three chemical individual and dual modification treatments on corn starch's physicochemical, thermal, and rheological properties. Ultrasonication and the three chemical treatments disrupted the starch granules with a decrease in particle size and a significant increase in the ζ-potential. The hydrophilicity of ultrasonic-oxidized dual-modified starch (U-O-CS) was the highest, at 0.854 g/g. The lipophilicity of ultrasonic-esterified dual-modified starch (U- E -CS) was the highest, at 1.485 g/g. The gelatinization temperature of ultrasonic, oxidation, and cross-linking modified starches increased significantly, with cross-linking starches being the largest. Oxidative treatment significantly decreased the starch's G' and G" and weakened the textural properties. The rheological properties of U-O-CS were further weakened. The G' of the starch decreased after the esterification treatment, while the G" increased, and the textural properties were cut. The maximum rheological and textural properties were obtained for crosslinked modification, with a hardness value of 284.70 g. [Display omitted] • Ultrasound has a synergistic effect on the properties of chemically treated starch. • Ultrasonic oxidation dual modified starch has the highest hydrophilicity. • Cross-linking starch has the best thermal stability and rheological properties. [ABSTRACT FROM AUTHOR]

Cold climate regions have great potential for wind power generation. The available wind energy in these regions is about 10% higher than in other regions due to higher wind speeds and increased air density. However, these regions usually have favorable icing conditions that lead to ice accumulation on the wind turbine blades, which in turn increases the weight of the blades and disrupts local airflow, resulting in a reduction in wind turbine performance. Considering this problem, plasma actuators have been proposed as devices for simultaneous flow control and deicing. These devices transfer momentum to the local airflow, improving the aerodynamic performances of the turbine blades while producing significant thermal effects that can be used to prevent ice formation. Considering the potential application of plasma actuators for simultaneous flow control and deicing, it is very important to investigate the thermal effects induced by these devices. However, due to the significant electromagnetic interference generated by the operation of these devices, there is a lack of experimental techniques that can be used to analyze them. In the current work, a background-oriented Schlieren system was developed and is presented as a new experimental technique for the thermal characterization of the plasma-induced flow. For the first time, the induced flow temperatures are characterized for plasma actuators with different dielectric materials and different dielectric thicknesses. The results demonstrate that, due to the plasma discharge, the temperature of the plasma-induced flow increases with the increase of the applied voltage and may achieve temperatures five times higher than the room temperature, which proves the potential of plasma actuators for deicing applications. The results are presented and discussed with respect to the potential application of plasma actuators for simultaneous flow control and deicing of wind turbine blades. [ABSTRACT FROM AUTHOR]

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Effective cooling technology is intensely demanded to cool the electronic devices within small space under high heat flux. Mini-grooved flat heat pipe (FHP) with simple structure, close contact with heat source, uniform temperature and high thermal conductivity can satisfy the demand of transferring the great heat rapidly and weakening the hot spot of electronic devices. As fine wick feature and distribution played a critical part in improving the performance of mini-grooved FHP, a thermal experiment was established to explore the heat transfer characterization of mini-grooved FHP with different wick structures and distributions. And a mathematical model in one dimension was set up to investigate the fluid flow and heat transmission performance of FHP with V-type or rectangle-type grooves, expecting to assist the experiment in understanding the operating mechanisms of mini-grooved FHP further. Effects of input heat, inclined angle, working temperature and wick structure were examined. It is found that among the V-type, rectangle-type and block-type mini-grooved FHPs, V-type FHP presents better heat transfer rate, while block-type FHP displays larger maximum heat transfer amount. V2 sloped convex gradient mini-grooved FHP owns the optimum overall performance. It possesses the merits of narrower grooves at the evaporation section, wider grooves at the condensation section and larger vapor chamber space, which can optimize the liquid and vapor circulation processes inside the FHP. Its thermal resistance and maximum temperature reduce by almost 9.7% and 3.4% separately in comparison with those of V1 straight mini-grooved FHP, which is beneficial to guarantee the reliability and stability of electronic devices. [ABSTRACT FROM AUTHOR]

In the framework of ISOL (isotope separation on-line) facilities, porous carbides are among the most employed target materials for the production of radioactive ion beams for research. As foreseen by the ISOL technique, a production target is impinged by an energetic particle beam, inducing nuclear reactions from such an interaction. The resulting radionuclides are subsequently released, thanks to the high target working temperature (1600–2000 °C); ionized; and extracted into a beam. Since the target microstructure and porosity play a fundamental role in the radionuclide release efficiency, custom-made target materials are often specifically produced, resulting in unknown thermal and structural properties. Considering that such targets might undergo intense thermal stresses during operation, a thermal and structural characterization is necessary to avoid target failure under irradiation. In the presented work, a custom-made porous titanium carbide that was specifically designed for application as an ISOL target was produced and characterized. The thermal characterization was focused on the evaluation of the material emissivity and thermal conductivity in the 600–1400 °C temperature range. For the estimation of a reference material tensile stress limit, the virtual thermoelastic parameter approach was adopted. In particular, for the aforementioned temperature range, an emissivity between 0.7 and 0.8 was measured, whereas a thermal conductivity between 8 and 10 W/mK was estimated. [ABSTRACT FROM AUTHOR]

Lithium-ion batteries are known for their high efficiency for storing electrical energy, especially for hybrid vehicles. In this research, the development of mixture composites in the cathode electrode of LIBs has been discussed and designed based on ternary solid solutions. We have given a novel synthesis and method preparation of cathode electrode materials to reduce costs while increasing the efficiency and simultaneity for the future of these technologies. The major problem in the LIBs is related to LiCoO2 as a popular cathode material that, although it has a high efficiency, is expensive and very toxic. Therefore, the usage of a lower weight of cobalt compared to the LiCoO2 cathode material is economically advantageous for this research. Several samples of the (1-x-y) LiCo1/3Ti1/3Fe1/3PO4 xLi2MnPO4 and yLiFePO4 system were synthesized via sol–gel experiments. Various stoichiometric amounts of the LiNO3, Li2MnPO4, Mn (Ac)2. 4H2O, Co (Ac)2.4H2O, Ti(NO3)2.6H2O and LiFePO4 have been used for several compositions of chrome, manganese, cobalt and titanium in 28 samples of (1-x-y) LiCo1/3Ti1/3Fe1/3PO4. By using thermal characterization, five samples have been selected due to their conditions in viewpoints of capacity and cyclability as well as activation energy, which is one of the major factors. These composites exhibited fairly consistent charge/discharge curves during the electrochemical testing. From the viewpoint of the physical and chemical properties, among these samples, the Li1.501Co0.389Ti0.055Fe0.055Mn0.501PO4 structure has a high efficiency compared to other compositions. [ABSTRACT FROM AUTHOR]

The development of bamboo fibre (BF) reinforced poly lactic acid (PLA) BF-PLA composites has been growing fast among the natural fibre reinforced composites (NFRCs) over the past few years. BF-PLA composites have gained significant interest as sustainable alternative materials for the engineering and industrial sectors. BF-PLA composites are getting popular due to their remarkable features such as eco-friendliness, biodegradability, recyclability, low cost, low specific weight, and improved mechanical and thermal properties. In this paper, a schematic review of the BF-PLA composites was conducted in terms of mechanical properties (i.e., tensile properties, flexural properties, and impact strength), thermal characteristics with and without chemical treatment, and creep behaviour. Moreover, the sustainability aspects, including biodegradability and recyclability of BF-PLA composites, have been discussed based on various manufacturing methods. In addition, the utilization of BF-PLA composites in the additive manufacturing industry, sustainable packaging, structural, dielectric, and automotive applications are also described to make elevations toward future research and industrial implementations or commercialization. Furthermore, the effects of 3D printing parameters on the mechanical and physical properties of printed BF-PLA objects have been summarized. Significantly, this paper highlights the limitations and future perspectives of the BF-PLA composites. [ABSTRACT FROM AUTHOR]