Tg Values Research Articles

On the glass transition temperature of TNT

In prior work (N. Shamim, Y. P. Koh, S. L. Simon and G. B. McKenna, "The glass transition of trinitrotoluene (TNT) by Flash DSC," Thermochimica Acta,620, 36–39 (2015)) results for the glass transition temperature Tg of TNT based on measurements using a rapid chip calorimeter were reported. In that work a silver paste was used to contain the liquid TNT on the chip sensor. In the present work we show that there was an interaction between the paste and the TNT that cause the reported Tg to be approximately 10 °C higher than what we find for the material when placed directly on the chip calorimeter sensor. The reasons for the differences in Tg values and similarities in the glassy fragility index m from the different sample preparations are presented and discussed.

The Properties of High-Performance Concrete with Manganese Slag under Salt Action.

Manganese slag (MS) containing a certain amount of active hydration substances may be used as a kind of cementitious material. In the present study, we measured the mass, the relative dynamic modulus of elasticity (RDME), and the flexural and compressive strengths of MS high-performance concrete (MS-HPC) with added basalt fibers exposed to NaCl freeze-thaw cycles (N-FCs), NaCl dry-wet alternations (N-DAs), and Na2SO4 dry-wet alternations (NS-DAs). Scanning electron microscope energy-dispersive spectrometer (SEM-EDS) spectra, thermogravimetric analysis (TG) curves, and X-ray diffraction spectroscopy (XRD) curves were obtained. The mass ratio of MS ranged from 0% to 40%. The volume ratio of basalt fibers varied from 0% to 2%. We found that, as a result of salt action, the mass loss rate (MLR) exhibited linear functions which were inversely correlated with the mass ratio of MS and the volume ratio of basalt fibers. After salt action, MLR increased by rates of 0~56.3%, but this increase was attenuated by the addition of MS and basalt fibers. Corresponding increases in RDME exhibited a linear function which was positively correlated with MS mass ratios in a range of 0~55.1%. The addition of MS and basalt fibers also led to decreased attenuation of mechanical strength, while the addition of MS led to increased levels of flocculent hydration products and the elements Mn, Mg, and Fe. CaClOH and CaSO4 crystals were observed in XRD curves after N-DA and NS-DA actions, respectively. Finally, the addition of MS resulted in increased variation in TG values. However, the opposite result was obtained when dry-wet actions were exerted.

Evaluation of hematological parameters and lipid profile in dyspeptic patient with gastric Helicobacter pylori infection, southern Ethiopia, 2022 GC

IntroductionHelicobacter pylori is gram-negative bacteria that mainly inhabits the human stomach and is one of the causes of dyspepsia. However, it is not confined to gastrointestinal tract and extends its pathogenesis on other system. PurposeTo evaluate lipid profiles and hematologic markers in dyspeptic individuals with and without H. pylori infection. Patients and methodsThe comparative cross-sectional study was conducted at Arba Minch General Hospital, from February 2022 to July 2022, 51 ​H. Pylori positive and 51 ​H. pylori-negative dyspeptic patients were recruited for this study by a non-probability purposive sampling technique. Using a pretested questionnaire, socio-demographic and behavioral variables were gathered. H. pylori antigen was detected in human fecal samples using the H. pylori Ag cassette for infection diagnosis. Blood samples were taken to evaluate lipid profile and hematological markers. SPSS version 21 was used to analyze the data and a P-value of <0.05 was regarded as statistically significant for all variables. ResultsThe study's findings revealed that the H. pylori-positive and H. pylori-negative study groups had different mean deviations for hematological parameters (Hg, RBC, HCT, MCV, MCH, and RDW) and lipid profiles. In the H. Pylori positive group compared to H. pylori-negative patients, the mean value of RDW (13.98 ​± ​0.96 vs. 14.96 ​± ​1.38) increased whereas other hematological profiles declined. When compared to H. pylori-negative dyspeptic individuals, there was a drop in the mean value of HDL (40.92 ​± ​5.64 vs. 37.65 ​± ​5.88) and increased the mean values of TC, TG, and LDL in H. pylori-positive patients. HDL showed a positive significant relationship with Hgb, RBC, and HCT r ​= ​0.39,r ​= ​0.38,r ​= ​0.43, respectively, while other lipid profiles (TC, TG, LDL) showed a negative significant correlation. ConclusionThe findings showed that H. pylori infection is related to altered lipid profiles and hematological markers, and HDL showed significant positive correlation with Hgb, RBC, and HCT.

Isobornyl and Isocamphyl Photostabilizers in Poly(lactic acid)-Based Electrospun Fibers.

In this work, electrospun polylactide fibers with new photostabilizing additives, 4-methyl-2,6-diisobornylphenol (DIBP) and N-isocamphylaniline (NICA), have been tested under the influence of UV-C radiation (254 nm). The changes in the polymers' chemical structure under UV-C radiation were revealed through the increase in absorption in the 3600-3100 cm-1 region in regard to the FTIR spectra. In the samples that were irradiated for 1 h, the stabilizing effect of the photoprotectors became most noticeable as the difference in the content of the hydroxyl groups in stabilized and the pure PLA reached a maximum. The TG-DSC method revealed that the most sensitive indicator of the irradiation effect was the glass transition temperature (Tg), which persisted after 2 h of irradiation when using photostabilizers and their combinations. The PLA/DIBP(1) and PLA/NICA(1) samples showed the best results in protecting PLA from UV-C radiation based on the Tg values; although, the mixture of DIBP and NICA was not as effective. The chemical structure of the photostabilized PLA samples was studied using NMR, GPC, and Py-GC/MS analysis. The electrospun polylactide fibers were mechanically tested and the effects of the electrospun samples on cell viability were studied.

Synthesis and Characterisation of 4D-Printed NVCL-co-DEGDA Resin Using Stereolithography 3D Printing

The design and manufacturing of objects in various industries have been fundamentally altered by the introduction of D-dimensional (3D) and four-dimensional (4D) printing technologies. Four-dimensional printing, a relatively new technique, has emerged as a result of the ongoing development and advancements in 3D printing. In this study, a stimulus-responsive material, N-Vinylcaprolactam-co-DEGDA (NVCL-co-DEGDA) resin, was synthesised by Stereolithography (SLA) 3D printing technique. The N-Vinylcaprolactam-co-DEGDA resins were initiated by the Diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (TPO) photoinitiator. A range of Di(ethylene glycol) diacrylate (DEGDA) concentrations in the NVCL-co-DEGDA resin was explored, ranging from 5 wt% to 40 wt%. The structural properties of the 3D printed objects were investigated by conducting Attenuated Total Reflectance–Fourier Transform Infrared Spectroscopy (ATR-FTIR). Additionally, the 3D printed samples underwent further characterisation through differential scanning calorimetry (DSC) and swelling analysis. The results revealed an inverse relationship between DEGDA concentration and Tg values, indicating that higher concentrations of DEGDA resulted in lower Tg values. Additionally, the pulsatile swelling studies demonstrated that increasing DEGDA concentration prolonged the time required to reach the maximum swelling ratio. These findings highlight the influence of DEGDA concentration on both the thermal properties and swelling behaviour of 3D printed samples.

Applying machine learning and quantum chemistry to predict the glass transition temperatures of polymers

Glass transition temperature (Tg) is important for understanding the physical and mechanical properties of a polymer material because it relates to the thermal energy required to transition between a hard glassy state and a soft rubbery one. Over the years, various models have been developed for predicting this thermal property from molecular structure to aid in designing novel polymers in selected classes. This work builds on those efforts by utilizing both machine learning (ML) and quantum chemistry (QC) techniques to develop models that can predict Tg values from the molecular structure under different data availability scenarios and for a wide variety of polymer types. For the ML model, a graph convolutional network (GCN) was used to map topological polymer features; this model was trained against a dataset of more than 7500 Tg values and resulted in a root mean square error (RMSE) of 38.1 °C. The QC-based regression model was trained on 83 Tg values and produced an RMSE of 34.5 °C. This work demonstrated that while both model techniques produce accurate predictions and are suitable for different data availability scenarios, the QC-based regression model offered a more interpretable model framework with significantly less training data.

Features of the Mechanism of Gas-phase Ignition of Wood Biomass Particles

ABSTRACT Use of woody biomass instead of coal as fuel for thermal power plants (TPP) is considered a promising direction for reducing emissions of anthropogenic substances during the operation of coal-fired thermal power plants. But the process of replacing coal with wood in the thermal power industry is happening very slowly due to objective reasons. The main one is the deposition of particles that have not fully passed the pyrolysis stage (in this case, a layer of substance in a resinous state is retained in the wood particle) on heating surfaces (for example, superheaters) and a decrease in the efficiency of using the heat of combustion of fuel as a result of contamination of the heating surfaces. Therefore, when developing technologies for burning dispersed wood in the furnaces of boiler units, reliable experimental data are required on the characteristic times of ignition and combustion of woody biomass particles, taking into account the time of transition from local (focal) gas-phase ignition to the combustion of volatiles in the entire vicinity of the particle (tsf). The article presents the results of experimental studies of flame propagation processes in the small vicinity of a particle during the ignition period. The experiments made it possible to establish that the flame propagation velocity in the small vicinity of the particle significantly depends on the ambient temperature. It is shown that under conditions of low-temperature heating (air temperature Tg = 873 K), the propagation velocity of the combustion (flame) is minimal. An increase in Tg values (from 873 K to 1273 K) leads to a significant (4–5 times) increase in the time of complete flame coverage of the particle. According to the results of the experiments, two heating modes were identified: high-temperature and low-temperature with a conditional interface Tg = 873 K. At Tg = 873 K, the characteristic particle size of wood biomass has no significant effect on the characteristics and conditions of flame propagation in a small vicinity of the particle. An increase in the ambient temperature (up to 1273 K) leads to an increase in the influence of particle size on the characteristics and conditions of flame propagation. A hypothesis describing the process of flame propagation has been developed.

Transfer learning-driven artificial intelligence model for glass transition temperature estimation of molecular glass formers mixtures

Predicting binary mixtures' glass transition temperature (Tg) is crucial in various fields, particularly for industrial materials affected by this property during production processes and in service-life. On the other hand, from the fundamental point of view, this predictive capability is relevant for understanding the chemical interactions between the two components and how this affects the Tg of the mixture. In this sense, some models provide different approaches for describing the Tg of the mixture. Among them, the Gordon-Taylor approach has been widely used since it only relies on the relationship between the Tg of the pure components, their weight fraction, and only one fitting parameter. Although simple, this approach still requires measurements of Tg of the pure components and at least some intermediated composition for the fitting procedure. In a previous work, our research has focused on neural networks methods for predicting Tg values directly from the chemical structure of monomers and molecules, but the scarcity of experimental data for binary mixtures limits the application of a similar approach. To address this problem, we propose to use in this work a transfer learning method that relays on the previous acquired knowledge of the chemical structure - Tg relationship, for the prediction of the Tg of the binary mixtures. Therefore, pure component characteristics are derived from chemical fingerprints originated in a pre-trained network, and enables a training process focused on their behavior within the mixtures. This approach successfully estimated K with very low deviations, even allowing for the exploration of the embedded chemical structure's relation to previously unknown mixtures.

Effect of counterions on the water sorption and glass transition properties of maltobionate salts

AbstractThe purpose of this study was to clarify the effect of counterions on the water sorption and glass transition properties of maltobionate salts. Sodium maltobionate (NaMb), potassium maltobionate (KMb), and magnesium maltobionate (MgMb2) were employed, and the values for calcium maltobionate (CaMb2) and maltose were taken from the literature. The water sorption isotherm of the samples was characterized using the Guggenheim-Anderson-de Boer model. The glass transition temperature (Tg) and freeze-concentrated glass transition temperature (Tg’) were evaluated by differential scanning calorimetry. The effect of water content on the Tg was analyzed using the Gordon-Taylor model. The order of the anhydrous Tg values of maltobionate salts was: KMb &lt; NaMb &lt; maltose &lt; MgMb2 &lt; CaMb2. The anhydrous Tg of the divalent cation forms (MgMb2 and CaMb2) was much higher than that of the monovalent cation forms (NaMb and KMb). The anhydrous Tg will be affected by the plasticizing effect and electrostatic effect of cations. The Tg depression induced by water plasticizing was greater for KMb than for the other maltobionate salts. The order of Tg’ values of freeze-concentrated maltobionate salts was: KMb &lt; maltose &lt; NaMb &lt; MgMb2 &lt; CaMb2. This trend was almost the same as that seen for anhydrous Tg, but the range of the Tg’ values (242.2–257.8 K) was much lower than that of the anhydrous Tg (346.9–421.3 K). The Tg’ appears to be affected by the strength of ionic interactions and amount of unfrozen water.

Structure, performance, and crystallization behavior of Turkey leonardite and raw kaolin added polylactic acid composite films

Polylactic acid (PLA) film composites filled with two clays, Raw Kaolin (KAO), an inorganic structure, and Leonardite (LEO), an organic structure, as well as KAO/LEO mixtures, were prepared via solvent casting method. The main aim of this research was to investigate both the individual and the synergetic effects of LEO and KAO; they are incorporated together into a PLA matrix. The influence of these fillers content on the morphological and structural characteristics of the composites was investigated by the DSC, TGA, FT-IR, SEM, XRD, color, haze, and opacity analysis. According to the TGA analysis, significant decreases in Tmax2 were observed with the addition of LEO in PLA. It is also seen in films with KAO/LEO that support this result. Utilizing the solvent casting method, two melting points were formed in PLA films. The P0 film has lower Tg, Tcc, and Tm1 values than other films. However, there were small changes in Tg and Tm2 values in all films. Up to 7.5% amount of LEO and KAO, the mechanical properties of the films improved. The 3L film exhibited the best mechanical properties. The filler materials used were mostly homogeneously distributed, according to the SEM analysis, and as the amount increased, agglomerations were observed in the fillings on the surface. The addition of LEO and KAO changed the surface color, visual appearance, and opacity significantly. The haze values of films are near 100. These film composites have been shown to improve many properties of the P0 film.

Dysregulation of miR-335-5p in People with Obesity and its Predictive Value for Metabolic Syndrome.

The epidemic of obesity and metabolic syndrome has become the most serious global public health problem. The part played by microRNA (miRNA) in the onset and progression of obesity and metabolic syndrome has been increasingly focused upon. The goal of this study was to explore miR-335-5p as a potential predictive biomarker or therapeutic target for obesity and metabolic syndrome. The expression level of miR-335-5p was detected by qRT-PCR. The diagnostic value of miR-335-5p was evaluated by ROC curve. The association between serum miR-335-5p levels and various clinical parameters was assessed using the chi-square test. Logistic regression analysis was used to evaluate the risk factors of metabolic syndrome in obese population. The biological processes and molecular mechanisms are studied through GO and KEGG enrichment analysis. The ROC curve analysis revealed that miR-335-5p could serve as a predictive indicator for the development of obesity accompanied by metabolic syndrome. Logistic regression analysis revealed that BMI, TG, FBG, HOMA-IR, and miR-335-5p expression represent independent risk factors of metabolic syndrome occurrence. Chi-square test analysis revealed that patients with higher values of BMI, SBP, DBP, TG, FBG, and HOMA-IR exhibited a more significantly increased expression of miR-335-5p in their serum. In conclusion, miR-335-5p holds predictive and diagnostic value for obesity and metabolic syndrome and has potential to serve as a biomarker for these conditions.

MA'AT Analysis: Unbiased Multi-State Conformational Modeling of Exocyclic Hydroxymethyl Group Conformation in Methyl Aldohexopyranosides.

MA'AT analysis (J. Chem. Inf. Model. 2022, 62, 3135-3141) has been applied to model exocyclic hydroxymethyl group conformation in methyl β-D-glucopyranoside (βGlcOMe), methyl β-D-galactopyranoside (βGalOMe), and methyl β-D-mannopyranoside (βManOMe) in an unbiased manner. Using up to eight NMR J-couplings sensitive to rotation about the C5-C6 bond (torsion angle ω), two-state models of ω were obtained that are qualitatively consistent with the relative populations of the gg, gt, and tg rotamers reported previously. MA'AT analysis gave consistent unbiased gt ⇌ tg models of ω in βGalOMe, with gt more populated than tg and mean values of ω for each population similar to those obtained from aqueous 1-μs MD simulation. Using different combinations of J-couplings had little effect on the βGalOMe model in terms of the mean values of ω and circular standard deviations (CSDs). In contrast, MA'AT analysis of ω in βGlcOMe and βManOMe produced more than one two-state model independent of the ensemble of J-values used in the analyses. These models were characterized by gg ⇌ gt conformer exchange as expected, but the mean values of ω in both conformers varied significantly in the different fits, especially for the gg rotamer. Constrained (biased) MA'AT analyses in which only staggered geometries about ω were allowed gave RMSDs slightly larger than those obtained from the unbiased fits, precluding an assignment of an unbiased model. It is unclear why MA'AT analysis gives consistent and predictable unbiased models of ω in βGalOMe but not in βGlcOMe and βManOMe. One possibility is that the distribution of ω in one or both of the gg and gt conformers in the latter does not conform to a von Mises function (i.e., is not Gaussian-like), but rather to a broad and/or flat distribution that cannot be fit by the current version of MA'AT. Nevertheless, the results of this study provide new evidence of the ability of MA'AT analysis to treat multi-state conformational exchange using only experimental NMR data, extending recent MA'AT applications to furanosyl ring pseudorotation (Biochemistry 2022, 61, 239-251).

Realization of customizable performance castor oil-based waterborne polyurethane antiseptic coatings via arbutin

The utilization of green and sustainable bio-based resources gets more important owing to the increasing shortage of petrochemical resources. Arbutin (AT) was considered to belong to a class of renewable polyhydroxy compounds due to its unique molecular structure. Hence, a molecular structure design strategy was employed to incorporate AT and castor oil into the backbone of anionic waterborne polyurethan (WPU). The effect of the AT content on the characteristics of WPU dispersion and casting film was thoroughly investigated. The result showed that the WPU films had excellent transparency, mechanical (the tensile strength was 28.4 MPa, the toughness was 34.3 MJ/m3), and thermodynamic properties, surpassing most current vegetable oil-based WPU systems. Notably, the WPU-AT20 film could pull target 18722 times its own weight, which could be ascribed to the cooperative effects of abundant rigid rings, H-bonds, and a higher physical crosslink density in systems. The Tg values of the WPU films were adjusted to range from 13.47 °C to 63.40 °C. The maximum value of Tg was, in particular, outstanding at present reported systems. Intriguingly, the WPU films still exhibited prominent anti-corrosion performance towards Q235# iron after severe weather conditions of outdoor storage for 4 months. The objective of this research was to offer simple and feasible strategies for preparing eco-friendly WPU coatings with excellent anti-corrosion performance.

Thermomechanical transitions of meat-analog based fried foods batter coating

This study aimed to characterize the thermomechanical transitions of meat-analog (MA) based coated fried foods. Wheat and rice flour-based batters were used to coat the MA and fried at 180 °C in canola oil for 2, 4 and 6 min. Glass-transition-temperature (Tg) of the coatings were assessed by differential scanning calorimetry, directly after frying or after post-fry holding. Mechanical texture analyzer and X-ray microtomography were employed to assess textural attributes and internal microstructure, respectively. Batter-formulation substantially impacted the Tg of fried foods coating i.e., crust. Tg of fried foods crust were ranged between −20 °C to −24 °C. Tg was positively correlated with frying time and internal microporosity (%), whereas negatively correlated with moisture content. Internal microstructure greatly influenced the textural attributes (hardness, brittleness, crispiness). Post-fry textural stability considerably impacted by Tg. Negative Tg value explains post-fry textural changes (hard-to-soft, brittle-to-ductile, crispy-to-soggy) of MA-based coated products at room-temperature (25 °C) and under IR-heating (65 °C).

Time‐Dependent Information Encryption in Liquid Crystalline Polymer with Programmable Glass Transition Temperature

AbstractTime‐dependent dynamic information encryption technology is a promising approach to enhancing the security and complexity of information transmission. Herein, a time‐dependent information encryption model from a liquid crystalline polymer (LCP) film with a programmable glass transition temperature (Tg) and gradually adjustable fluorescence is demonstrated. The programmable Tg is achieved by adjusting the degree of order of the LC molecules via a configuration interconversion of spiropyran‐based materials (SPBMs), which can convert between a V‐shaped colorless spiro (SP) and a rodlike dark‐colored merocyanine (MC) form. An LCP film obtained by visible light polymerization exhibits a lower Tg than UV light, because the SPBM molecules keep different configurations in the two films. By adjusting the ratio of two isomerization forms of SPBM molecules during the polymerization process, the Tg values of LCP films can change from 11.6 °C to 31.1 °C. Based on the isomerization rate of SPBM in the LCP films with different Tg, time‐dependent information encryption is successfully achieved.

Crosslinked Polyesters as Fully Biobased Coatings with Cutin Monomer from Tomato Peel Wastes.

Cutin, one of the main structural components of tomato peels, is a waxy biopolymer rich in hydroxylated fatty acids. In this study, 10,16-dihydroxyhexadecanoic acid (10,16-diHHDA) was extracted and isolated from tomato peels and exploited to develop fully crosslinked polyesters as potential candidates for replacing fossil-based metal protective coatings. A preliminary screening was conducted to select the base formulation, and then a design of experiments (DoE) was used as a methodology to identify the optimal composition to develop a suitable coating material. Different formulations containing 10,16-diHHDA and other biorefinery monomers, including 2,5-furandicarboxylic acid, were considered. To this end, all polyesters were characterized through differential scanning calorimetry (DSC) and gel content measurements to determine their Tg value and crosslinking efficiency. Compositions exhibiting the best trade-off between Tg value, chemical resistance, and sufficiently high 10,16-diHHDA content between 39 and 48 wt.% were used to prepare model coatings that were characterized for assessing their wettability, scratch hardness, chemical resistance, and adhesion to metal substrates. These polyester coatings showed a Tg in the range of 45-55 °C, a hydrophobic behavior with a water contact angle of around 100°, a good solvent resistance (>100 MEK double rubs), and an adhesion strength to steel higher than 2 MPa. The results obtained confirmed the potential of cutin-based resins as coatings for metal protection, meeting the requirements for ensuring physicochemical properties of the final product, as well as for optimizing the valorization of such an abundant agri-food waste as tomato peels.

Eco-friendly composites with specific functional properties

The development of sustainable hydrophobic composite coatings is of high interest for aircraft applications. Currently, the use of natural derived functionalized microparticles as filler to obtain hydrophobic epoxy-based coatings was not deeply investigated. In this scenario, a novel hydrophobic epoxy-based composite including waste hemp microparticles functionalized with silica layer, 3-aminopropyltriethoxysilane, polypropylene-graft-maleic anhydride and silanes (hexadecyltrimethoxysilane and 1H,1H,2H,2H- Perfluorocotyltriethoxysilane) is presented. The resulting coating was casted on typical aeronautical panel, based on carbon-fiber-reinforced polymers, to achieve an improved hydrophobicity and anti-icing property induced by functionalized hemp microparticles.The wettability and anti-icing property were investigated. Compared to unfilled epoxy resin, the obtained composite coating achieved a greater water contact angle of 30° and doubled increase in icing time. Despite the low content (2 wt.%) of hemp particles, DSC analysis displayed a relevant increase in Tg value, confirming an efficient interaction between the epoxy matrix and the functionalized hemp filler. AFM analysis proved how the presence of hemp filler leads to an increase in roughness due to the hierarchical structure formed by the long chains of silane molecules. The combination of silane activity and rough morphology allows the development of hemp composite coatings with enhanced hydrophobicity, anti-icing behavior and thermal stability for aircraft applications.

Association Between Monocyte-to-High-Density Lipoprotein Ratio and Prediabetes: A Cross-Sectional Study in Chinese Population.

The monocyte-to-high-density lipoprotein cholesterol (MHR) ratio has been linked to metabolic disorders. However, there is limited research on the predisposition to MHR and prediabetes. Hence, we conducted a study to investigate the relationship between MHR and the prevalence of prediabetes. In total, 85,293 participants were included in our cross-sectional observational study. Multivariable regression analysis, subgroup analyses, and interaction testing were used to determine the relationship between MHR and prediabetes. To explore the non-linear association of MHR with prediabetes risk, generalized additive model (GAM) and smoothing splines were applied. The threshold effect analysis of MHR on the risk of prediabetes was further employed to identify the turning point. After controlling for covariates, the results indicated that a positive correlation persisted between MHR and prediabetes (odds ratio (OR) =1.64, 95% confidence interval (CI), 1.48-1.82), and subgroup analyses found a more robust correlation between MHR and prediabetes in individuals with lower age, SBP, DBP, TG, TC and higher values of BMI and LDL-C than in their counterparts. Additionally, the correlation between MHR and the risk of prediabetes was found to be non-linear, with a turning point of -0.4 (Log-Likelihood Ratio, P< 0.001). The impact of variables on the two sides of the turning point were 1.94 (1.72, 2.19) and 0.88 (0.69, 1.14). The positive correlation between MHR and the risk of prediabetes in Chinese participants was observed to be non-linear, and MHR ≤ -0.4 was strongly positively correlated with prediabetes risk.

Analysis of the thermal properties in short sansevieria cylindrica fibre/PLA composites processed by twin screw extruder followed by hot press molding technique

Abstract Short Sansevieria cylindrica fibre/polylactic acid composites (SCFP) were fabricated using a twin screw extruder followed by the hot press technique, with variations in fibre loadings of 10 wt%, 20 wt%, 30 wt% and 40 wt%. The thermal properties of SCFP were assessed through dynamic mechanical analysis (DMA), thermomechanical analysis (TMA), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Notably, the samples loaded with 40 wt% of fibre exhibited an increased storage modulus. In terms of loss modulus, the fibre-loaded samples displayed high values, indicating more heat is released during DMA experiment. Interestingly, the composite trend did not solely rely on increasing fibre loading, highlighting the intricate interplay between reinforcement and matrix crucial for determining viscoelastic properties across various temperatures. The TGA results revealed a decrease in inflection temperature with increasing fibre loadings, accompanied by a proportional rise in residues. The DSC thermograms indicated minimal differences in Tg, Tcc, and Tm values among composites with varying fibre loadings. However, neat PLA showed slightly higher values than the composites. On the other hand, reinforcing SCF into the PLA matrix promoted the crystallization of PLA by 1%–3% with the maximum degree of crystallinity of 25.4% obtained for 30 wt% of SCFP.

Tailoring of physical, optical, and thermal properties of Se50-xTe30Ge20Sbx chalcogenide glasses: Influence of metalloids

The compositional dependence on physical and spectroscopic characteristics of chalcogenide Se50-xTe30Ge20Sbx (x = 5, 10, 15, and 20 at. wt%) bulk glassy systems has been explored in this communication. Numerous physical and optical features are rigorously examined by using the best glass sample among all the prepared samples. The XRD pattern reveals the amorphous character of the synthesized materials. Some of the physical parameters like density, and compactness are gradually increasing with the Sb addition, while the free volume percentage and excess volume follow the decreasing trend. The optical properties have been precisely inspected by UV-Vis spectroscopy in the (200–800) nm spectral range. The optical bandgap (Eopt) values are found to decline from (1.09–0.85) eV with Sb content. The observed refractive index, n values experience a subsequent decline with incident energy. By using the Wemple and DiDomenico (WDD) single oscillator model, the refractive index dispersion curve has been studied, and the dispersion parameters are discussed. The valence band (VB) and conduction band (CB) locations are estimated, and the obtained result reveals the VB potential increases from −15,089 eV to −1.3899 eV, while that of CB decreases from −0.4113 eV to −0.5303 eV with the rise of Sb-concentration. The cohesive energy (CE) values have been estimated by using the chemical bond approach (CBA). Investigation reveals the CE of the system decreases from 45.237 kcal/mole to 44.229 kcal/mole justifying the decrement in obtained band gap energy values of the studied glassy systems. Furthermore, the compositional dependency of various thermal parameters is investigated by using the DSC approach. The glass transition (Tg), and peak crystallization (Tp) were significantly affected by Sb addition. The obtained values of Tg are found to decrease from (337–305 K), while the thermal stability is found to increase with the Sb incorporation.