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'Rhythmite', Ca29(SiO4)8Cl26, an anthropogenic calcium chloride silicate from the Chelyabinsk coal basin (South Ural, Russia), was investigated using chemical microprobe analysis, in situ single-crystal X-ray diffraction analysis (27–727 °C), and Raman spectroscopy. 'Rhythmite' is orthorhombic, Pnma: a = 17.0749(6), b = 15.1029(5), c = 13.2907(4) Å, and V = 3427.42(18) Å3 (R1 = 0.045). The crystal structure of 'rhythmite' consists of a porous framework formed by Ca-O bonds and SiO4 tetrahedra with additional Ca2+ cations and Cl− anions in the structure interstices. The framework is built up from multinuclear [Ca15(SiO4)4]14+ fundamental building blocks (FBBs) cut from the crystal structure of α-Ca3SiO4Cl2 ('albovite'). The FBBs are linked by sharing common Ca atoms to form a network with an overall pcu topology. The empirical chemical formula was calculated as Ca29.02(Si7.89Al0.05P0.05)Ʃ7.99O32Cl26 (on the basis of Cl + O = 58). 'Rhythmite' is stable up to 627 °C and expands slightly anisotropically (αmax/αmin = 1.40) in the ab and bc planes and almost isotropically in the ac plane (α33/α11 = 1.02) with the following thermal expansion coefficients (×106 °C−1): α11 = 14.6(1), α22 = 20.5(4), α33 = 15.0(3), and αV = 50.1(6) (room temperature). During expansion, the silicate tetrahedra remain relatively rigid with average bond length changes of less than 0.5%. A structural complexity analysis indicates that 'rhythmite' is complex, with IG,total = 920.313 (bits/u.c.), which significantly exceeds the average value of structural complexity for silicates and is caused by the modular framework construction and the presence of a large number of independent positions in the crystal structure. [ABSTRACT FROM AUTHOR]

Abstract In a rapidly changing thermal environment, reptiles are primarily dependent on in situ adaptation because of their limited ability to disperse and the restricted opportunity to shift their ranges. However, the rapid pace of climate change may surpass these adaptation capabilities or elevate energy expenditures. Therefore, understanding the variability in thermal traits at both individual and population scales is crucial, offering insights into reptiles' vulnerability to climate change. We studied the thermal ecology of the endangered Greek meadow viper (Vipera graeca), an endemic venomous snake of fragmented alpine-subalpine meadows above 1600 m of the Pindos mountain range in Greece and Albania, to assess its susceptibility to anticipated changes in the alpine thermal environment. We measured preferred body temperature in artificial thermal gradient, field body temperatures of 74 individuals in five populations encompassing the entire geographic range of the species, and collected data on the available of temperatures for thermoregulation. We found that the preferred body temperature (T p ) differed only between the northernmost and the southernmost populations and increased with female body size but did not depend on sex or the gravidity status of females. T p increased with latitude but was unaffected by the phylogenetic position of the populations. We also found high accuracy of thermoregulation in V. graeca populations and variation in the thermal quality of habitats throughout the range. The overall effectiveness of thermoregulation was high, indicating that V. graeca successfully achieves its target temperatures and exploits the thermal landscape. Current climatic conditions limit the activity period by an estimated 1278 h per year, which is expected to increase considerably under future climate scenarios. Restricted time available for thermoregulation, foraging and reproduction will represent a serious threat to the fitness of individuals and the persistence of populations in addition to habitat loss due to mining, tourism or skiing and habitat degradation due to overgrazing in the shrinking mountaintop habitats of V. graeca.

Zinc oxide-supported magnesium aluminate (ZnO/MgAl2O4) was synthesized by the one-pot fusion method, consuming magnesium nitrate, aluminum nitrate, and citric acid as starting precursors. The samples prepared were annealed at temperatures ranging from 700 to 900°C to study the influence of annealing temperature on thermal behaviour and crystalline properties. The thermal behaviour of ZnO/MgAl2O4 was characterized by thermogravimetric analysis (TGA), while the structural properties and crystalline phase of ZnO/MgAl2O4 were analysed by X-ray diffraction (XRD). The TGA results show that there were three stages of decomposition in the sample. The first stage indicates the removal of water content from the sample; the second stage indicates the decomposition of citric acid; and the third stage represents the crystallization phase formation at a temperature range of 800- 950°C. The percentage of citric acid decomposition increases with increasing annealing temperatures up to 800°C. However, the decomposition rate gradually reduces at annealing temperatures between 850 and 900°C. XRD analysis results suggest that microstructured ZnO/MgAl2O4 with high crystallinity can be obtained at the highest annealing temperature. It can be concluded that the result of thermal behaviour represented by the decomposition stage is corroborated with structural and crystalline properties at increasing annealing temperatures.

Coal fly ash (CFA), a by-product of coal combustion, is a valuable raw material for various applications. However, the heterogeneous nature of the composition and properties of CFA provides challenges to its effective usage and utilisation. This study investigates the thermal behaviour of the fly ashes of lignite (FA1) and brown coal (FA2) and their fractions obtained by dry aerodynamic separation. Thermal analysis techniques, including thermogravimetry (TG), differential scanning calorimetry (DSC), and evolved gas analysis (EGA), were used to characterise the behaviour of the fly ash fractions while heating up to 1250 °C. The results reveal distinct differences in the thermal behaviour between ash types and among their different size fractions. For the FA1 ashes, the concentration of calcium-rich compounds and the level of recrystallisation at 950 °C increased with the decrease in particle size. The most abundant detected newly formed minerals were anhydrite, gehlenite, and anorthite, while coarser fractions were rich in quartz and mullite. For the FA2 ashes, the temperature of the onset of melting and agglomeration decreased with decreasing particle size and was already observed at 995 °C. Coarser fractions mostly remain unchanged, with a slight increase in quartz, mullite, and hematite content. Recrystallisation takes place in less extension compared to the FA1 ashes. The findings demonstrate that the aerodynamic separation of fly ashes into different size fractions can produce materials with varied thermal properties and reactivity, which can be used for specific applications. This study highlights the importance of thermal analysis in characterising fly ash properties and understanding their potential for utilisation in various applications involving thermal treatment or exposure to high-temperature conditions. Further research on advanced separation techniques and the in-depth characterisation of fly ash fractions is necessary to obtain materials with desired thermal properties and identify their most beneficial applications. [ABSTRACT FROM AUTHOR]

More effective use of solar energy in hot water systems is made possible by optimising heat transfer and flow resistance. In light of this, Research has been conducted to enhance convective heat transfer while analysing flow friction characteristics for best performance, resulting in the design of novel inserts known as customised twists, which increase the efficiency of the solar hot water system. A conventional, plain tube heater is used as a baseline for the study on thermal characteristics, heat transportation and flow friction attributes. A thorough analysis and comparison of the thermal behaviour of the system with customised twist inserts that have been modified using rods and spacers of different lengths is performed. As a result of the induced disturbance in the fluid particle flow pattern throughout the length of risers, a significant improvement in the coefficient of convective heat transfer is observed. The study validated the correlations for the convective heat transfer coefficient and the resistance coefficient against previous research findings. The findings indicated that the thermal efficiency of the full-length twist-inserted system is almost three times greater than that of a plain collector while doubling its pressure drop. The findings of this research could be useful in designing low-cost, compact solar water heaters. [ABSTRACT FROM AUTHOR]

This study presents the thermal and thermo-mechanical responses of a pilot energy wall located in Melbourne, Australia, which is believed to be one of the first instrumented energy soldier piled walls in the world. The full-scale field thermal and thermo-mechanical conditions of the wall were monitored during the period of a full-cycle thermal response test (TRT) conducted on a single soldier pile over 2 months. The monitored pile and ground temperature responses reveal the significance of the thermal condition in the excavated space on the thermal performance of such energy geostructures, which increases complexities in design and analysis. Furthermore, this study reports the profiles of axial strains and induced thermal stresses in the tested soldier pile, demonstrating how the applied thermal load from the TRT influenced the mechanical performance of the pile and wall and how the restrictive action of the support elements controlled the induced conditions. Here, we show that soldier pile responds differently from energy piles or borehole heat exchangers; however, residual axial strains were minimal and similar to those reported in energy piles foundations due to a thermo-elastic response to the imposed thermal loads and wall rigidity. Finally, the unique experimental dataset is made available for further studies. [ABSTRACT FROM AUTHOR]

A novel fiber reinforced cementitious composites was developed by incorporating microencapsulated phase change materials (PCMs) and nanographene oxide (NGO) to enhance the composites' thermal properties without compromising the compressive strength. Regarding the thermo-mechanical properties, with the addition of NGO, while mechanical properties improve, thermal mass increases and the heat storage ability of the produced composite material enhances. In this situation; it can be interpreted that it will be possible to benefit more from the energy stored by PCMs, as the energy required to change the temperature of the unit mass of the material will decrease. The environmental impact assessment has also revealed that CO 2 emissions from production increase with the use of PCMs. However, it has been determined that the addition of NGOs will make a positive contribution to the life cycle, as CO 2 emissions resulting from cement will decrease. In conclusion, a novel fiber reinforced composite with enhanced thermal and mechanical properties by combining PCMs and NGO has shown a great potential for environmentally friendly buildings with the integration of structure, energy conservation and long term durability. [ABSTRACT FROM AUTHOR]

This study explores the synthesis and diverse properties of newly synthesised water‐soluble cobalt (II) complexes (1–3). Analysis of the complexes through various methods, including Hirshfeld surface analysis, reveals distinctive intermolecular interactions, particularly robust H‐bonding contributions to crystal packing. 2D fingerprint plots provide quantitative insights into supramolecular interactions, while TGA‐DSC analysis elucidates multi‐step decomposition processes, mainly involving organic moieties. FT‐IR and SCXRD confirm the structures of the complexes. Magnetic susceptibility measurements show paramagnetic behaviour in all complexes. FMO calculations expose HOMO‐LUMO gaps and charge transfer processes, with NBO analysis emphasizing the significance of chloride, nitrogen, and oxygen atoms in coordination. In addition, pkCSM profile was carried out. The biological properties of the complexes reveal potent antibacterial activity for 2 and 3 against Gram‐positive and Gram‐negative bacteria. Despite lower antibacterial efficacy compared to standard antibiotics, their water solubility suggests potential human pharmacological applications. In terms of anti‐inflammatory activity, all three complexes exhibit concentration‐dependent prevention of ovalbumin denaturation, with 2 being the most effective. Compound 3, despite having seven carboxyl groups, exhibits the weakest anti‐inflammatory effect, potentially attributed to complex formation obscuring these groups. Furthermore, all complexes display antioxidant activities; 1 and 2 are greater than BHT in the ferric thiocyanate assay. [ABSTRACT FROM AUTHOR]

In the present review work, it is proposed to carry out a bibliographic analysis about the thermal behaviour of the dolomitic mineral. The state of the art of dolomite currently indicates a growing use as a refractory material due to the cheaper alternative it represents compared to other materials such as magnesium oxide. The importance of dolomite apart from its application in the steel industry lies in the fact that it has expanded to other industrial fields such as the production of catalysts, catalyst supports, and industrial effluent purification materials. In these and other applications, understanding the thermal behaviour of the material is necessary to evaluate the feasibility of application. In this review, the different experimental proposals developed over time in terms of thermal behaviour are studied, emphasizing the reaction mechanisms that have been proposed in different investigations. [ABSTRACT FROM AUTHOR]

AbstractThe present study aimed to investigate the in-vitro antidiabetic activity of collagen hydrolysate (CH) from Asian bullfrog skin and its application as a bioactive compound in dark chocolate bars. Papain (3% [w/w]) was used to obtain CH with a simultaneous conjunction of ultrasound. CH possessed α-amylase inhibitory activity with an IC50 value of 3.60 mg/mL, while results from inhibition reaction kinetics revealed that CH inhibited α-amylase in a non-competitive mode. Different concentrations (0.5, 1.0, and 2.0% [w/w]) of CH were then fortified into dark chocolate bars, and the physicochemical characteristics, breaking strength, and rheological behaviour of the resulting chocolate were investigated and compared with a control (without CH addition). A higher level of CH significantly enhanced antidiabetic activity against α-amylase (p ≤ 0.05) in chocolate bar. Chocolate bar with 2% CH complied with the nutritional claim requirement for ‘source of protein’ with lower fat content and energy value, while sensory evaluation revealed good organoleptic properties.

Fly-ash-based geopolymer pastes with the addition of expanded vermiculite (EV) powder were synthesised and their microstructure, compressive strength, setting time, moisture control, extent of efflorescence and thermal conductivity were studied. It was found that the addition of EV resulted in an increase in the standard-consistency water consumption and setting times. As a consequence, excessive addition of EV resulted in a larger amount of harmful pores, which was detrimental for the compressive strength of the paste. However, geopolymer pastes with an appropriate amount of EV (2–7 wt%) showed a slight increase in compressive strength because of the filler effect. Mg2+ and Fe3+ diffused from the EV interlayers through ion exchange between the EV and the geopolymer, and participated in geopolymerisation. This was reflected by the formation of N-(M)-A-(F)-S-H, as evidenced by scanning electron microscopy with energy dispersive X-ray spectroscopy and Fourier-transform infrared spectroscopy. In addition, Na+/Mg2+ or Na+/Fe3+ ion exchange reduced the mobility of Na+ the ions and therefore decreased the extent of efflorescence. Moreover, EV addition favoured an improvement in moisture content and the thermal conductivity properties of the geopolymer paste. [ABSTRACT FROM AUTHOR]

Drug candidates must undergo thermal evaluation as early as possible in the preclinical phase of drug development because undesirable changes in their structure and physicochemical properties may result in decreased pharmacological activity or enhanced toxicity. Hence, the detailed evaluation of nitrogen-rich heterocyclic esters as potential drug candidates, i.e., imidazolidinoannelated triazinylformic acid ethyl esters 1–3 (where R1 = 4–CH3 or 4–OCH3 or 4–Cl, and R2 = –COOC2H5) and imidazolidinoannelated triazinylacetic acid methyl esters 4–6 (where R1 = 4–CH3 or 4–OCH3 or 4–Cl, and R2 = –CH2COOCH3)—in terms of their melting points, melting enthalpy values, thermal stabilities, pyrolysis, and oxidative decomposition course—has been carried out, using the simultaneous thermal analysis methods (TG/DTG/DSC) coupled with spectroscopic techniques (FTIR and QMS). It was found that the melting process (documented as one sharp peak related to the solid–liquid phase transition) of the investigated esters proceeded without their thermal decomposition. It was confirmed that the melting points of the tested compounds increased in relation to R1 and R2 as follows: 2 (R1 = 4–OCH3; R2 = –COOC2H5) < 6 (R1 = 4–Cl; R2 = –CH2COOCH3) < 5 (R1 = 4–OCH3; R2 = –CH2COOCH3) < 3 (R1 = 4–Cl; R2 = –COOC2H5) < 1 (R1 = 4–CH3; R2 = –COOC2H5) < 4 (R1 = 4–CH3; R2 = –CH2COOCH3). All polynitrogenated heterocyclic esters proved to be thermally stable up to 250 °C in inert and oxidising conditions, although 1–3 were characterised by higher thermal stability compared to 4–6. The results confirmed that both the pyrolysis and the oxidative decomposition of heterocyclic ethyl formates/methyl acetates with para-substitutions at the phenyl moiety proceed according to the radical mechanism. In inert conditions, the pyrolysis process of the studied molecules occurred with the homolytic breaking of the C–C, C–N, and C–O bonds. This led to the emission of alcohol (ethanol in the case of 1–3 or methanol in the case of 4–6), NH3, HCN, HNCO, aldehydes, CO2, CH4, HCl, aromatics, and H2O. In turn, in the presence of air, cleavage of the C–C, C–N, and C–O bonds connected with some oxidation and combustion processes took place. This led to the emission of the corresponding alcohol depending on the analysed class of heterocyclic esters, NH3, HCN, HNCO, aldehydes, N2, NO/NO2, CO, CO2, HCl, aromatics, and H2O. Additionally, after some biological tests, it was proven that all nitrogen-rich heterocyclic esters—as potential drug candidates—are safe for erythrocytes, and some of them are able to protect red blood cells from oxidative stress-induced damage. [ABSTRACT FROM AUTHOR]

The solution cast (SC) prepared polymer nanocomposite (PNC) films, based on poly(vinylidene fluoride) (PVDF) and poly(methyl methacrylate) (PMMA) blend host matrix with varying amounts of barium titanate (BaTiO3) as nanofiller, were thermally treated through standardized hot pressed (HP) procedure at 160 °C under the pressure of 2 tons. The optical characterization including absorbance, reflectance, and percentage transmittance for UV–vis radiations of 200–800 nm, direct and indirect energy band gaps, Urbach energy, refractive index, extinction coefficient, optical range dielectric permittivity and optical conductivity as well as non-linear optical parameters of these solution cast-hot pressed (SC-HP) PNC films are performed and confirmed their dependency on the nanofiller concentrations. These SC-HP processed PNC films showed reduced UV–vis absorbance, direct energy band gap, and the degree of crystallinity of the PVDF crystalline phase whereas the crystallite melting temperature significantly enhanced in comparison to the same composition SC prepared PNC films. The dielectric permittivity and electrical conductivity values, at 27 °C, for these thermally treated PNC films are improved appreciably over the broadband radio frequency range of 1 MHz to 1 GHz. The technologically favoured changes in various optical and dielectric parameters establish the appropriateness of the thermal treatment process for envisaging applications of these PNCs in advances of high-performance flexible-type optoelectronic and radio electronic devices. [ABSTRACT FROM AUTHOR]

This study aims to determine mechanical and thermal properties of Saint-Maximin limestone, similar to the Lutetian stone found in the vaults of the Notre-Dame de Paris cathedral, and their variations after heating–cooling cycles at temperatures up to 800 °C. An extensive experimental campaign, including both destructive and non-destructive testing, was carried out. The results indicate that the samples can be considered to be isotropic, and the effect of temperature on Poisson's ratio, static modulus of elasticity, compressive and tensile strengths were measured. Non-destructive testing revealed that the usual correlation equations between ultrasonic measurements and mechanical properties are not valid for heated stone samples, particularly when estimating Poisson's ratio. An alternative measurement method using impulse modal analysis was proposed to overcome this issue. Uniaxial compressive tests on specimens of different geometries were used for the estimation of shape factors specific to Saint-Maximin stone. Some of these shape factors contradict the current European standard for stone, which seems to overestimate the effect of slenderness. The study also suggests shape factors after heating at 300 °C and 600 °C to account for the effect of heating on the compressive strength. The results demonstrate that, while the correlations established for stones at room temperature remain valid, they are not necessarily accurate after a heating–cooling cycle. This study provides important information for the numerical modelling of this material from mechanical and thermal perspectives. [ABSTRACT FROM AUTHOR]

To overcome the disadvantage of strong moisture absorption of traditional moisturizing agent propylene glycol in heated tobacco products, a new type of moisturizing agent propylene glycol pyrrole ester was prepared, and its thermal behavior and moisture retention effect in reconstituted tobacco leaves were investigated by thermogravimetric- derivative thermogravimetry-differential scanning calorimetry, pyrolysis gas chromatography/ mass spectrometry and low-field nuclear magnetic resonance imaging. The results showed that: the thermal weight loss interval of propylene glycol pyrrole ester was from 149.9 °C to 400. 0°C and the maximum weight loss rate 77.39% reached at 298.7 °C. Propylene glycol pyrrole ester was subjected to thermal cracking at 200 °C, 300 °C and 350 °C, and it mainly could crack and decompose to release pyrrolidic acid and propylene glycol, among which propylene glycol could harmonise and reduce the sense of dryness of the tobacco. The moisture retention ability of reconstituted tobacco leaves added with propylene glycol pyrrole ester in low humidity environment was higher than that of the blank group, but lower than that of the propylene glycol group; The area of bound water inside the reconstituted tobacco leaves in a low humidity environment of propylene glycol group, propylene glycol pyrrole ester group and blank group was 75%, 70%, and 68%, respectively. Propylene glycol pyrrole ester could reduce the strong moisture absorption of reconstituted tobacco leaves while maintaining a certain degree of moisture retention. [ABSTRACT FROM AUTHOR]

Polymer-based nanocomposites combine increased mechanical properties and heat resistance than pure polymer materials. In this article, poly(methyl methacrylate-co-N-vinyl-2-pyridone)/polyethylene glycol/multi-walled carbon nanotube (P(MMA-co-VP)/PEG/MWCNTs) nanocomposites were prepared by radical copolymerization. To improve the dispersion of MWCNTs in P(MMA-co-VP)/PEG, they were functionalized and characterized with Raman, FTIR spectroscopy, and SEM. The effect of functionalized MWCNTs content on the mechanical and thermal properties of nanocomposites was studied. Although MWCNTs had the potential to induce PEG crystallization, no PEG crystals were found in P(MMA-co-VP)/PEG/MWCNTs. At the same time, MWCNTs had obvious effects as enhancers, and with the increase of their content, the mechanical properties, dynamic modulus and thermal stability of nanocomposites were improved compared with P(MMA-co-VP)/PEG. [ABSTRACT FROM AUTHOR]

The possibility of dental pulp damage during dental procedures is well known. According to studies, during finishing and polishing without cooling, temperatures of up to 140 °C or more can be generated. There are many studies that have analysed the influence of the finishing and polishing of fillings on the mechanical parameters, but the analysis of thermal parameters has led to uncertain results due to the difficulty of performing this in vivo. Background: We set out to conduct a study, using the finite element method, to determine the extent to which the type of class II cavity and the volume of the composite filling influence the duration of heat transfer to the pulp during finishing and polishing without cooling. Materials and Methods: A virtual model of an upper primary molar was used, with a caries process located on the distal aspect, in which four types of cavities were digitally prepared: direct access, horizontal slot, vertical slot and occlusal–proximal. All four cavity types were filled using a Filtek Supreme XT nanocomposite. Results: The study showed that the filling volume almost inversely proportionally influences the time at which the dental pulp reaches the critical temperature of irreversible damage. The lowest duration occurred in occlusal–distal restorations and the highest in direct access restorations. Conclusions: based on the results of the study, a working protocol can be issued so that finishing and polishing restorations without cooling are safe for pulpal health. [ABSTRACT FROM AUTHOR]

The current research focuses on the efficiency of energy recovery from non-hazardous organic wastes. It entails the generation of low-chloride refuse-derived fuel (RDF) from municipal solid waste (MSW) through moderate pyrolysis of combustible components. The moderate pyrolysis settings and composition ratio of biogenic/non-biogenic content from MSW combination (food waste, plastic waste, and paper waste) had a significant impact on the thermochemical characteristics and fuel behavior of RDF. Furthermore, pyrolysis with optimal MSW composition was studied to reduce toxic elements (chlorides, sulphides, and nitrides) and enhance the energy value in RDF by utilizing potassium-rich (waste orange peels (OP); banana peels (BP); and maize cob (MC)) and calcium-rich species (waste animal bone meal (ABM); egg shells (ES); and mussel shells (MS)) as natural additives. The results showed that increasing the pyrolysis temperature maximized the carbon concentration with reduced oxygen moieties (low O/C ratio), indicating a high energy value as the oxygenates were eliminated during moderate pyrolysis. The RDF treated at 400 °C (SF4-400) with MSW composition of 55% non-biogenic carbon and 45% biogenic carbon resulted in HHV of 29.22 MJ kg−1, the lowest ash concentration (0.96%), and a densified microstructural surface. The addition of natural maize cob additive into MSW (SF4-400-MC) yielded the maximum HHV (33.07 MJ kg−1) with considerable reductions in chlorides (71.43%), sulphides (87.50%), and insignificant nitrides content, all of which meet ASTM RDF quality criteria Grade I. [ABSTRACT FROM AUTHOR]

Urea complexes of magnesium sulfate have been intensively studied due to their application in many areas of life, including agricultural chemistry, pharmacy, medicine, etc. The aim of this study is to add new knowledge about the trends and consistencies in the preparation procedures of MgSO4·nOC(NH2)2·mH2O phases. A set of analytical methods was used to characterize their structure, thermal and spectroscopic properties. The conditions for obtaining the three complexes in pure form were specified and the crystal structures of MgSO4·OC(NH2)2·2H2O and MgSO4·OC(NH2)2·3H2O were determined. The spectroscopic data of the considered compounds were analysed with respect to their structural and chemical properties. Thermal analyses showed that both the melting point and the urea decomposition temperature depend on the OC(NH2)2: H2O ratio in the octahedral environment of the magnesium ion in the studied structures. [ABSTRACT FROM AUTHOR]

The physicochemical properties, fatty acid profile, and thermal analysis of soybean and sesame oils were evaluated after microwave and conventional heating. The microwave exposure times were 2, 4, 6, 8, 10, and 12 min, correlated with their appropriate temperatures of 96, 150, 183, 210, 225, and 242 °C in conventional heating. The degree of thermal oxidation was measured by determining the peroxide value (PV), p-anisidine value (p-AV), iodine value, acid value (AV), total polar compounds, total phenolic content, and fatty acid content. The microwave-heated samples showed higher PV levels than their conventional heated counterparts. The most intensive peroxide formation for both oils and treatments was found at 210 °C and 8 min, respectively, while decomposition was dominant over this temperature. When samples were heated in a microwave, the p-AV of both oils increased substantially, revealing a higher increase in the level of secondary oxidation products. The degradation of phenolic compounds was more intense under microwave heating than under conventional heating. Unsaturated fatty acids underwent isomerization from cis to trans form due to the heat treatment of oils. Thermal analysis revealed transformations in soybean and sesame oils, thermal effects, mass losses through thermal treatment up to 1000 °C, respectively, the impact of microwave and conventional heating. [ABSTRACT FROM AUTHOR]

The composite fin component is developed with surface fragmentation and molecular deployment, contributing to both molecular areas and surface walls. One of the main benefits of natural contribution is the preservation of good surface conditions and wall temperatures. Composite fins regulate the quality of endurance rate and noise level. The heat flux rate and temperature distribution rate are higher compared to natural controls. Additionally, they facilitate a strong bond between composite fins and radiator pipes. The surface characteristics and heat transfer rate are greater in the fins. While normal fins partially cool the heat rates, the composite fins, with their low heat transfer rate, primarily cool the heat rates from the inlet to the outlet valve. [ABSTRACT FROM AUTHOR]

Purpose: The thermal behaviour of nanoclay can be considered an important factor in obtaining high-performance polymer nanocomposite. Thus, the current study aims to investigate the effect of plasma treatment on the thermal stability of two organically modified nanoclays, Cloisite 30B (C30B) and Nanomer I.34TCN (I.34TCN), compared with pristine NaMMT. Design/methodology/approach: The nanoclays were studied and characterised using Thermogravimetric Analysis (TGA). TGA was used to measure the weight loss of the plasmatreated and untreated nanoclays (C30B, I.34TCN, and NaMMT nanoclays) over a 30-630 C temperature range. Findings: Based on TGA results, the decomposition of all plasma-treated nano clays (C30B, I.34TCN and pristine NaMMT) was shifted to a lower temperature than in the untreated ones at all those stages. Thus, plasma treatment was successfully used as a convenient method to alter the chemical structure and surface morphology of MMT nanoclays for better thermal behaviour and filling distribution. Research limitations/implications: This hypothesis can be corroborated by X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) for a better understanding of the structural and surface changes that occurred due to the plasma action, which can provide an interpretation of the changes in the thermal behaviour of nanoclays. Practical implications: The plasma treatment, therefore, can improve the thermal stabilisation of the nanocomposite powders for the LS fabricated parts and even for the surrounding powder for the recovery process. Plasma-treated nano clay, therefore, can be used to reinforce polymers with an expectation of increasing the thermal stability of the resultant composites. Thus, the plasma-treated composite can be fabricated for laser sintering applications in fields that require high thermal stability. Originality/value: The surface modification of nanoclay powders via plasma treatment can be used as a convenient method to alter the chemical structure and surface morphology for better thermal behaviour and filling distribution. [ABSTRACT FROM AUTHOR]

Two series of chiral liquid crystal compounds were synthesised from benzoic acid containing cholesterol with different carbon-chain lengths and bisphenol monoester containing camphoric acid with different carbon-chain lengths, named BCP-C and DCP-C. The structure of the monomers is characterised by IR, 1H NMR and 13C NMR, which indicate that the synthesised molecule conforms to the molecular design. The textures of monomers were characterised by POM, and their selective reflection was studied. It was found that the synthesised liquid crystal compounds exhibited good liquid crystal and optical properties. The phase transition behaviour was characterised using DSC, and the results were consistent with those observed by POM. TGA showed that they had good thermal stability. [ABSTRACT FROM AUTHOR]

A LaB6 particles decorated Ti48Al2Cr2Nb composite almost free of any cracks has been successfully fabricated by LPBF in this work. To better understand the role of LaB6 inoculant in LPBF-fabricated γ-TiAl alloys, the effects of LaB6 inoculant on the thermal behavior, microstructure evolution and crack sensitivity were investigated by simulation and experimental methods. Based on a single particle model, it was predicted that the addition of LaB6 particle could induce a significant change in temperature gradient G. Due to the LaB6→La2O3 in-situ transformation, the temperature field was severely perturbed, thus causing random G orientations of the matrix surrounding the particle. Furthermore, based on the multi-particle model, predictions indicated that the 0.5 wt% LaB6 inoculant led to a significant decrease of the Gmax from 1.14× 107 °C/m to 6.9 × 106 °C/m but a little influence on solidification rate R at solidified front, therefore contributing to a lower G/R and resultant larger undercooling. In this condition, fine equiaxed grains with random orientations were expected to dominate in the solidified microstructure, which got well verified by the experiments where the maximum texture index dropped from 15.06 to 2.23 and the average grain size decreased from 16.13 ± 8.52 μm to 1.52 ± 1.10 μm due to the addition of LaB6 inoculant. What's more, the LaB6 inoculant also induced an apparent reduce in crack density from 7.02 ± 1.06 mm/mm2 to 0.52 ± 0.12 mm/mm2 and a rise in relative density from 97.65 ± 0.58% to 99.88 ± 0.10%, which could be mainly attributed to grain refinement, grain purification and texture attenuation.

Coal fly ash (CFA), a by-product of coal combustion, is a valuable raw material for various applications. However, the heterogeneous nature of the composition and properties of CFA provides challenges to its effective usage and utilisation. This study investigates the thermal behaviour of the fly ashes of lignite (FA1) and brown coal (FA2) and their fractions obtained by dry aerodynamic separation. Thermal analysis techniques, including thermogravimetry (TG), differential scanning calorimetry (DSC), and evolved gas analysis (EGA), were used to characterise the behaviour of the fly ash fractions while heating up to 1250 °C. The results reveal distinct differences in the thermal behaviour between ash types and among their different size fractions. For the FA1 ashes, the concentration of calcium-rich compounds and the level of recrystallisation at 950 °C increased with the decrease in particle size. The most abundant detected newly formed minerals were anhydrite, gehlenite, and anorthite, while coarser fractions were rich in quartz and mullite. For the FA2 ashes, the temperature of the onset of melting and agglomeration decreased with decreasing particle size and was already observed at 995 °C. Coarser fractions mostly remain unchanged, with a slight increase in quartz, mullite, and hematite content. Recrystallisation takes place in less extension compared to the FA1 ashes. The findings demonstrate that the aerodynamic separation of fly ashes into different size fractions can produce materials with varied thermal properties and reactivity, which can be used for specific applications. This study highlights the importance of thermal analysis in characterising fly ash properties and understanding their potential for utilisation in various applications involving thermal treatment or exposure to high-temperature conditions. Further research on advanced separation techniques and the in-depth characterisation of fly ash fractions is necessary to obtain materials with desired thermal properties and identify their most beneficial applications.

High-entropy fluorite oxides (HEFOs) must be evaluated under various test conditions to be used as advanced thermal barrier coating (TBC) materials. This study investigated the chemical valence, lattice parameters, and thermal expansion coefficient (TEC) of an HEFO (Zr 0.2 Ce 0.2 Hf 0.2 Y 0.2 Al 0.2)O 2-δ heated and cooled between 1200 °C and 1500 °C in air. Thermogravimetry-differential scanning calorimetry (TG-DSC) was used to probe the temperature ranges of the reduction and oxidation reactions, and X-ray photoelectron spectroscopy was used to determine the valence states of the chemical elements. In-situ high-temperature X-ray diffraction was used for examining the crystal phase and calculating the TECs. The results show that chemical valences related to Zr, Hf, Y, and Al oxidation states were maintained during the entire thermal cycle, whereas these for Ce underwent partial valence transitions. In other words, Ce4+ was partially reduced to Ce3+ when heated from (1200–1300) °C, and Ce3+ was partially re-oxidized to Ce4+ as the temperature increased from 1400 °C to 1500 °C. Such chemical reactions correlate well with the TG-DSC results. The TEC values ranged from (9.58–9.28) × 10−6 K−1 and exhibited a weak, nonlinear dependency on temperature, decreasing with an increase in temperature, except when heated from 1200 °C to 1240 °C. The reduction and oxidation reactions had a minor effect on the TEC and the differences due to heating and cooling were appreciable yet subtle when compared to that at the same temperature, with the maximum difference being less than 0.2 × 10−6 K−1. [ABSTRACT FROM AUTHOR]

Geopolymers prepared with class C fly ash (FA) often suffer from a flash geopolymerisation rate, making it difficult to work. Class F FA, however, may have low reactivity, so an admixture must be added to solve this problem. This research highlighted the use of mixed class C and class F FA as a precursor for geopolymer preparation to alleviate such problems. Optimisation of the precursor recipe and the solid-to-liquid ratio (S/L) was assessed. The highest compressive strength (30.54 MPa) and a suitable initial (136 min) and final (240 min) setting times were obtained with S/L = 2.00, and 50 : 50 proportions of class C to class F FA. The fire resistance test on a 10 mm thick geopolymer panel at 1000°C for 180 min showed a maximum temperature of ∼570–580°C on the reverse side without catastrophic failure, suggesting it can be applied for use in fire retardation. [ABSTRACT FROM AUTHOR]

The fire resistance of construction materials is an essential part of safety requirements in the construction industry. In this work, experimental investigations were conducted to understand the thermal behaviour, spalling, transfer characteristics, strength, and microstructures of self-cured high-strength plain (HSGC) and steel-fibre-reinforced geopolymer concrete (S–HSGC) under severe fire scenarios with peak temperatures of 275, 560, and 825 °C; the peak was maintained for a period of 120 min after reaching it. Forty-eight standard cylindrical specimens for each mixture were prepared to test and analyse their time–heat response, gradients, visual appearance, spalling, density change, water absorption, and compressive strength before and after fire exposure. Additionally, Scanning Electron Microscopy (SEM) along with Energy Dispersive X-ray Analysis (EDX) were utilised to analyse the internal structures and phase transformations. The thermal analysis showed that no cases of explosive spalling were recorded during sample exposure to various fires, while the used hook-end steel fibres had an influence on the considered test variables. The sample cores almost reached the target heat, and the thermal saturation degree at the peak ranged from 55 to 97%. The experimental findings also revealed slight surface cracking after exposure to 560 °C fires, while the surface cracking was more obvious for specimens exposed to 825 °C. Moreover, the residual compressive strength of the S–HSGC at various fires was noticeably 10.20% higher than that of the HSGC. Also, state-of-the-art research data were used to discuss the prediction model's performance. The SEM and EDX results showed that the self-cured geopolymerization process was effective and successful in producing gels, in addition to the significant phase transformations in microstructures at different fires. This study presented sophisticated data on the behaviour of HSGC and S–HSGC exposed to fires up to 825 °C. [ABSTRACT FROM AUTHOR]

In this article, for the first time, TG-DSC and TG-FTIR investigations of potential pharmaceutics, i.e., analgesic and anticancer active annelated triazinones (1–9) have been presented. The thermal behaviour of these molecules was established in oxidative and inert conditions. The solid–liquid phase transition for each compound (1–9) was documented by one sharp DSC peak confirming the high purity of each sample studied. All the molecules were characterised in terms of calorimetric changes and mass changes during their heating. They revealed high thermal stability in oxidative and inert conditions. The observed tendency in thermal stability changes in relation to a substituent present at the phenyl moiety was found to be similar in air and nitrogen. It was confirmed that annelated triazinones 1–9 were stable up to a temperature range of 241–296 °C in air, and their decomposition process proceeded in two stages under oxidative conditions. In addition, it was established that their thermal stability in air decreased in the following order of R at the phenyl moiety: 4-Cl > 3,4-Cl2 > H > 3-Cl > 4-CH3 > 2-CH3 > 3-CH3 > 2-Cl > 2-OCH3. The volatile decomposition products of the investigated molecules were proposed by comparing the FTIR spectra collected during their thermogravimetric analysis in nitrogen with the spectra from the database of reference compounds. None of annelated triazinones 1–9 underwent any polymorphic transformation during thermal studies. All the compounds proved to be safe for erythrocytes. In turn, molecules 3, 6, and 9 protected red blood cells from oxidative damage, and therefore may be helpful in the prevention of free radical-mediated diseases. [ABSTRACT FROM AUTHOR]

The granite waste generated from the granite cutting and polishing industries contributes to lot of environmental contamination and health hazards. In the present work, an attempt has been made to assess the method to minimise environmental problems associated with granite dust pollution to the possible extent by converting the granite dust waste into value added high voltage electrical insulator products. Two types of epoxy matrices comprising bisphenol-A diglycidyl ether-phenalkamine (ER-1) and bisphenol-A diglycidyl ether-methyl hexahydrophthalic anhydride (ER-2) separately reinforced with varying weight percentages of (20, 40, 60, 80 and 100 wt%) of granite dust. The matrices and composites obtained were characterized for their structural, morphology, hydrophobic properties, thermal stability, mechanical strength, thermal conductivity, thermal resistivity, electrical resistivity, breakdown voltage and dielectric strength behaviour using appropriate analytical testing methods. Data resulted from different studies, it was inferred that the composites prepared using ER-2 possess better properties than those of ER-1. The composites with 100 wt% of cutting waste granite fly dust reinforced ER-2 possesses the higher values of electrical surface resistivity (5.22 × 1012 Ω), and electrical volume resistivity (5.60 × 1013 Ω) than those of neat ER-2 matrix (surface resistivity 4.82 × 109 Ω and volume resistivity 2.48 × 1013 Ω). The breakdown voltage and dielectric strength of ER-2 matrix were increased from 28 ±1 kV and 14 ± 0.5 kV/mm to 34 ±1 kV and 17 ± 0.5 kV/mm respectively, when reinforced with 100 wt % granite dust. The value of breakdown voltage was increased by 22% for 100 wt% granite dust reinforced composites when compared to that of neat epoxy matrix.

Drug candidates must undergo thermal evaluation as early as possible in the preclinical phase of drug development because undesirable changes in their structure and physicochemical properties may result in decreased pharmacological activity or enhanced toxicity. Hence, the detailed evaluation of nitrogen-rich heterocyclic esters as potential drug candidates, i.e., imidazolidinoannelated triazinylformic acid ethyl esters 1–3 (where R1 = 4–CH3 or 4–OCH3 or 4–Cl, and R2 = –COOC2H5) and imidazolidinoannelated triazinylacetic acid methyl esters 4–6 (where R1 = 4–CH3 or 4–OCH3 or 4–Cl, and R2 = –CH2COOCH3)—in terms of their melting points, melting enthalpy values, thermal stabilities, pyrolysis, and oxidative decomposition course—has been carried out, using the simultaneous thermal analysis methods (TG/DTG/DSC) coupled with spectroscopic techniques (FTIR and QMS). It was found that the melting process (documented as one sharp peak related to the solid–liquid phase transition) of the investigated esters proceeded without their thermal decomposition. It was confirmed that the melting points of the tested compounds increased in relation to R1 and R2 as follows: 2 (R1 = 4–OCH3; R2 = –COOC2H5) < 6 (R1 = 4–Cl; R2 = –CH2COOCH3) < 5 (R1 = 4–OCH3; R2 = –CH2COOCH3) < 3 (R1 = 4–Cl; R2 = –COOC2H5) < 1 (R1 = 4–CH3; R2 = –COOC2H5) < 4 (R1 = 4–CH3; R2 = –CH2COOCH3). All polynitrogenated heterocyclic esters proved to be thermally stable up to 250 °C in inert and oxidising conditions, although 1–3 were characterised by higher thermal stability compared to 4–6. The results confirmed that both the pyrolysis and the oxidative decomposition of heterocyclic ethyl formates/methyl acetates with para-substitutions at the phenyl moiety proceed according to the radical mechanism. In inert conditions, the pyrolysis process of the studied molecules occurred with the homolytic breaking of the C–C, C–N, and C–O bonds. This led to the emission of alcohol (ethanol in the case of 1–3 or methanol in the case of 4–6), NH3, HCN, HNCO, aldehydes, CO2, CH4, HCl, aromatics, and H2O. In turn, in the presence of air, cleavage of the C–C, C–N, and C–O bonds connected with some oxidation and combustion processes took place. This led to the emission of the corresponding alcohol depending on the analysed class of heterocyclic esters, NH3, HCN, HNCO, aldehydes, N2, NO/NO2, CO, CO2, HCl, aromatics, and H2O. Additionally, after some biological tests, it was proven that all nitrogen-rich heterocyclic esters—as potential drug candidates—are safe for erythrocytes, and some of them are able to protect red blood cells from oxidative stress-induced damage.

The possibility of dental pulp damage during dental procedures is well known. According to studies, during finishing and polishing without cooling, temperatures of up to 140 °C or more can be generated. There are many studies that have analysed the influence of the finishing and polishing of fillings on the mechanical parameters, but the analysis of thermal parameters has led to uncertain results due to the difficulty of performing this in vivo. Background: We set out to conduct a study, using the finite element method, to determine the extent to which the type of class II cavity and the volume of the composite filling influence the duration of heat transfer to the pulp during finishing and polishing without cooling. Materials and Methods: A virtual model of an upper primary molar was used, with a caries process located on the distal aspect, in which four types of cavities were digitally prepared: direct access, horizontal slot, vertical slot and occlusal–proximal. All four cavity types were filled using a Filtek Supreme XT nanocomposite. Results: The study showed that the filling volume almost inversely proportionally influences the time at which the dental pulp reaches the critical temperature of irreversible damage. The lowest duration occurred in occlusal–distal restorations and the highest in direct access restorations. Conclusions: based on the results of the study, a working protocol can be issued so that finishing and polishing restorations without cooling are safe for pulpal health.

In this research, the thermal behaviour of two dolostone samples of Argentine origin has been studied. First, a physicochemical characterization of the raw materials was carried out, determining their chemical and mineralogical composition. The thermal response of the materials was evaluated using TGA, DTA, muffle calcination, XRD and FTIR techniques. The thermal tests consisted of calcination schedules at temperatures and times of 750 °C in 1 and 3 h and 950 °C in 1, 3 and 4 h. With all these tests, the mechanism of thermal decomposition was established, taking as principle that a reaction mechanism must be coincident with all the experimental data. The results of the experiments indicate a three-stage reaction mechanism, the first stage being a high entropy process that, according to free energy calculations, this mechanism is more satisfactory than the current decomposition mechanism in calcium and magnesium carbonates separately.

Within the scope of this research, studies on nano-materials used in geopolymer concrete mixtures and their effects on the thermal behavior of geopolymer concrete are reviewed and summarized. Geopolymer is an environmentally friendly, economical and durable material. In recent years, studies on the thermal behavior of geopolymer concrete have been increasing. In these studies, various nano-materials were used in the geopolymer concrete matrix to improve the thermal behavior of geopolymer concrete. In addition, some of these nano-materials are industrial waste materials. Since these materials are used in geopolymer mixtures, it contributes to the solution of the storage problem of materials and environmental problems that may arise from these materials. The type of nano-material used in the geopolymer, its ratio, curing conditions, temperature and exposure time affect the thermal behavior of the geopolymer. In the studies conducted, it has been determined that these nano-materials generally improve the thermal behavior of geopolymer concrete. [ABSTRACT FROM AUTHOR]

Some changes in the starch properties are derived from physical or chemical treatments. Thus, 0.1 mol L−1, 0.5 mol L−1 hydrochloric acid were established and ultrasound (US) applied for 15 and 30 min to modify the native starch. In addition, the double modification was also tested, applying US after the acid modification. The native starch of the taro (with 23.31% amylose content) showed lower tendency to red colour and tended to yellow. Changes were observed after the application of the treatments. Greater thermal stability was displayed for modified starches, mainly due to ultrasound. In addition, the modification resulted in reduction of the temperatures and enthalpy involved in starch gelatinisation. The structure of the starch granules showed an irregular polyhedral shape with a smooth surface, no changes after the modifications, slight variation of the relative crystallinity and A-type diffraction pattern. [ABSTRACT FROM AUTHOR]

This study focuses on the thermo-hydro-mechanical (THM) analysis of the behaviour of a full-scale engineered barriers experiment designed to study the long-term response of a disposal concept for high-level radioactive waste (HLW) and spent fuel (SF). Crucially, the test involved two dismantling operations, a partial one after 5 years of heating and a final one, after 18·3 years of operation, allowing the direct observation of the state of the barrier at two different times. The coupled THM modelling discussed in this paper mainly focuses on the last 13 years of test operation and also on the final dismantling of the barrier system. The numerical model was unchanged from the early stages of the test, so the results presented can be considered as blind predictions. The numerical model predicted reasonably well the state of the barrier and its evolution, especially in terms of the distribution of the bentonite dry density, confirming the predictive capability of the model to capture the transient THM processes. The combination of experimental and numerical investigations, involving one of the most long-lasting full-scale in situ experiments monitoring the behaviour of the barrier components of an HLW/SF repository, has led to a better understanding of the THM behaviour of this complex system. [ABSTRACT FROM AUTHOR]

Structural characteristics of serpierite samples from Zvezdel, Bulgaria, and Lavrion, Greece, are reported. The thermal behaviour of serpierite from Lavrion is discussed. The chemical composition of the studied samples is analysed by energy-dispersive spectroscopy (EDS) and confirmed by single-crystal structure refinements. The obtained chemical formulas correspond well to that of serpierite with Cu:Zn ratio varying between 2.9 and 5.6. The sample from Zvezdel, with composition Ca[Cu3.3Zn0.7(OH)6(SO4)2•3H2O, crystallizes in the monoclinic crystal system, with space group I2 and unit-cell parameters a = 18.418(3), b = 6.220(1), c = 12.091(2) Å, β = 90.78(1)˚, whereas the one from Lavrion Ca[Cu2.8Zn1.2(OH)6(SO4)2]•3H2O, shows similar unit-cell parameters a = 18.394(1), b = 6.256(1), c = 12.097(1) Å, β = 90.92(1)˚, but higher I2/m space-group symmetry. Both studied crystals exhibit serpierite structure topology, but different stacking sequence of the octahedral layers. While in previously studied serpierite of Sabelli and Zanazzi (Acta Cryst B24:1214-1221, 1968) there are two layers per unit cell, in currently studied samples there is only one. As a consequence, their unit-cell volumes are half than that of the first structurally characterized serpierite specimen with SG C2/c and unit-cell parameters a = 22.186(2), b = 6.250(2), c = 21.853(2) Å, β = 113.36(1)˚. Taking into account the structural peculiarities of the studied samples they are considered as serpierite polytypoids. [ABSTRACT FROM AUTHOR]

Urea complexes of magnesium sulfate have been intensively studied due to their application in many areas of life, including agricultural chemistry, pharmacy, medicine, etc. The aim of this study is to add new knowledge about the trends and consistencies in the preparation procedures of MgSO4·nOC(NH2)2·mH2O phases. A set of analytical methods was used to characterize their structure, thermal and spectroscopic properties. The conditions for obtaining the three complexes in pure form were specified and the crystal structures of MgSO4·OC(NH2)2·2H2O and MgSO4·OC(NH2)2·3H2O were determined. The spectroscopic data of the considered compounds were analysed with respect to their structural and chemical properties. Thermal analyses showed that both the melting point and the urea decomposition temperature depend on the OC(NH2)2: H2O ratio in the octahedral environment of the magnesium ion in the studied structures.