Search Results (81)

Identifying sustainable and efficient methods for the degradation of plastic waste in landfills is critical for the implementation of the Saudi Green Initiative, the European Union’s Strategic Plan, and the 2030 United Nations Action Plan, all of which are aimed at achieving a sustainable environment. This study assesses the influence of palm fronds (PFR) on the thermal degradation of polypropylene plastic (PP) using TGA/FTIR experimental measurements, thermo-kinetics, and machine learning convolutional deep learning neural networks (CDNN). Thermal degradation operations were conducted on pure materials (PFR and PP) as well as mixed (blended) materials containing 25% and 50% PFR, across degradation temperatures ranging from 25 to 600 °C and heating rates of 10, 20, and 40 °C·min⁻¹. The TGA data indicated a synergistic interaction between the agricultural waste (PFR) and PP plastic, with decreased thermal stability at temperatures below 500 °C, attributed to the hemicellulose and cellulose present in the PFR biomass. In contrast, at temperatures exceeding 500 °C, the presence of lignin retards the degradation of the PFR biomass and blends. Activation energy values between 81.92 and 299.34 kJ·mol⁻¹ were obtained through the application of the Flynn–Wall–Ozawa (FWO) and Kissinger–Akahira–Sunose (KAS) model-free methods. The application of CDNN facilitated the extraction of significant features and labels, which were crucial for enhancing modeling accuracy and convergence. This modeling and simulation approach reduced the overall cost function from 41.68 to 0.27, utilizing seven hidden neurons, and 673,910 epochs in 13.28 h. This method effectively bridged the gap between modeling and experimental data, achieving an R² value of approximately 0.992, and identified sample composition as the most critical parameter influencing the thermolysis process. It is hoped that such findings may facilitate an energy-efficient pathway necessary for the thermal decomposition of plastic materials in landfills. Full article

This work aimed to conduct a kinetic study of cotton stalks (CSs) through TGA to examine the impact of reaction conditions on bio-oil yield derived from CS slow pyrolysis using a tube furnace lab-scale reactor, as well as a characterization of bio-oil and biochar products. The iso-conversional approaches of Kissinger–Akahira–Sunose (KAS) and Flynn–Wall–Ozawa (FWO) were applied to estimate kinetic parameter activation energy (E_a) for the range of conversion degrees (α = 0.1–0.9). The kinetic results demonstrated that the average values of E_a for secondary pyrolysis were lower compared to those of primary pyrolysis; this could be explained by the fact that mainly cellulose degrades during primary pyrolysis, which requires more energy to be degraded. The pyrolysis findings indicated that the highest yield of bio-oil was 38.5%, which occurred at conditions of 500 °C and 0.5–1 mm size, while retention time showed an insignificant effect on pyrolysis oil. GC–MS analysis demonstrated that bio-oil is dominated by phenol compounds, which account for more than 40% of its components. SEM and XRD analyses emphasized that biochar is porous and has an amorphous shape, respectively. It can be concluded that these outcomes confirm that CSs have the potential to be a good candidate for a feedstock material for bioenergy production via the pyrolysis process. Full article

This study presents a comprehensive kinetic and thermodynamic investigation of dried orange peel (OP) combustion, employing thermogravimetric analysis (TGA) and differential thermogravimetry (DTG) at high heating rates (20–80 K min⁻¹). This gap in high heating rate analysis motivates the novelty of present study, by investigating OP combustion at 20, 40, 60, and 80 K min⁻¹ using TGA, to closely simulate rapid thermal conditions typical of industrial combustion processes. Thermal decomposition occurred in three distinct stages corresponding sequentially to the dehydration, degradation of hemicellulose, cellulose, and lignin. Activation energy (E_a) was calculated using six model-free methods—Friedman (FR), Flynn–Wall–Ozawa (FWO), Kissinger–Akahira–Sunose (KAS), Starink (STK), Kissinger (K), and Vyazovkin (VY)—yielding values between 64 and 309 kJ mol⁻¹. The E_a increased progressively from the initial to final degradation stages, reflecting the thermal stability differences among biomass constituents. Further kinetic analysis using the Coats–Redfern (CR) model-fitting method identified that first-order (F1), second-order (F2), and diffusion-based mechanisms (D1, D2, D3) effectively describe OP combustion. Calculated thermodynamic parameters—including enthalpy (ΔH), Gibbs free energy (ΔG), and entropy (ΔS)—indicated the endothermic and increasingly non-spontaneous nature of the reactions at higher conversions. These findings demonstrate the potential of OP, an abundant agricultural waste product, as a viable bioenergy resource, contributing valuable insights into sustainable combustion processes. Full article

Background: Distal humerus physeal separation (DHPS) presents a rare injury type in young children often associated with misdiagnosis and delayed treatment. The aim of this study was to summarize all the available current evidence regarding the management and outcome of DHPS and determine the incidence of complications and particularly the cubitus varus deformity and avascular necrosis of the trochlea. Methods: A systematic review was conducted under the PRISMA guidelines. Medline/Pubmed, Scopus, Web of Science, and Cochrane were searched for studies dealing with children suffering from traumatic DHPS. Results: Twelve studies with a total of 257 children with DHPS were included for analysis. The mean age was 16.8 months (range: 0.1–46 months) with a mean follow-up of 37 months (range: 0.5–516 months). Non-accidental trauma was reported in 17.2% and misdiagnosis at initial assessment in 7.8%. Closed reduction and percutaneous pinning (CRPP) was the treatment of choice in 54.4%, open reduction and percutaneous pinning (ORPP) in 26.5%, closed reduction and cast immobilization (CR+cast) in 10.9%, and cast immobilization without reduction in 8.2%. The average range of extension–flexion arc was 2.1° to 127.8° (range: −10–140°). The mean Bauman’s angle was 72.4° (range: 66–79°), the mean shaft–condylar angle was 43.8° (range: 25–59°), the mean humeral length was 21.9 cm (range: 15.5–25.8 cm), and the mean carrying angle was 5.1° (range: 16° varus–19° valgus). According to Flynn’s criteria, 85.2% of cases were classified as excellent or good. The ORPP technique was associated with excellent results, while the CR+cast treatment combination was correlated with the poorest outcome (p = 0.001). Cubitus varus occurred in 18.9% (34 cases) and was highly correlated with CR+cast or cast immobilization alone without fracture reduction (p = 0.014). Avascular necrosis of the trochlea was found in 3.9% (7 cases) and was mainly apparent after cast immobilization without reduction (p < 0.001). Conclusions: Post-traumatic cubitus varus deformity may be encountered in approximately one-fifth of young children with DHPS. Surgical intervention with either CRPP or ORPP is the most effective treatment approach, leading to superior functional outcome and a lower complication rate. Full article

The buildup of abandoned plastics in the environment and the need to optimize agricultural waste utilization have garnered scrutiny from environmental organizations and policymakers globally. This study presents an assessment of the thermal decomposition of date seeds (DS), polypropylene homopolymer (PP), and their composites (DS/PP) through experimental measurements, machine learning convolutional deep neural networks (CDNN), and kinetic and thermodynamic analyses. The experimental measurements involved the pyrolysis and co-pyrolysis of these materials in a nitrogen-filled thermogravimetric analyzer (TGA), investigating degradation temperatures between 25 and 600 °C with heating rates of 10, 20, and 40 °C.min⁻¹. These measurements revealed a two-stage process for the bio-composites and a decrease in the thermal stability of pure PP due to the moisture, hemicellulose, and cellulose content of the DS material. By utilizing machine learning CDNN, algorithms and frameworks were developed, providing responses that closely matched ($R^2~0.942$) the experimental data. After various modelling modifications, adjustments, and regularization techniques, a framework comprising four hidden neurons was determined to be most effective. Furthermore, the analysis revealed that temperature was the most influential parameter affecting the thermal decomposition process. Kinetic and thermodynamic analyses were performed using the Coats–Redfern and general Arrhenius model-fitting methods, as well as the Flynn–Wall–Ozawa and Kissinger–Akahira–Sunose model-free approaches. The first-order reaction mechanism was identified as the most appropriate compared to the second and third order F-Series solid-state reaction mechanisms. The overall activation energy values were estimated at 51.471, 51.221, 156.080, and 153.767 kJ·mol⁻¹ for the respective kinetic models. Additionally, the kinetic compensation effect showed an exponential increase in the pre-exponential factor with increasing activation energy values, and the estimated thermodynamic parameters indicated that the process is endothermic, non-spontaneous, and less disordered. Full article

Branch wood, as a renewable biomass resource, presents certain challenges due to its high volume, complex physical properties, difficulty in handling, and relatively high production costs. Potassium chloride (KCl) treatments were applied to ash branch wood (ABW) using solutions with concentrations of 5%, 10%, and 15% via immersion. Pyrolysis tests were performed at different pyrolysis temperatures (450 °C, 600 °C, 750 °C) and different pyrolysis times (2 h, 3 h, 4 h). The thermal degradation behavior was meticulously examined through Thermogravimetric Analysis (TGA). Furthermore, the pyrolysis kinetics were assessed using the Flynn–Wall–Ozawa (FWO) model, which allowed for the determination of the kinetic parameters and the exploration of the catalytic influence of KCl on the pyrolysis process. The morphology and adsorption properties of the biochar were evaluated employing SEM-EDS and BET characterization methods, respectively. The results show that the higher the impregnation concentration of ABW, the greater the shift in the TG and DTG curves, and the lower the initial temperature and maximum weight loss temperature in the devolatilization stage. The calculation of pyrolysis kinetic parameters indicates that adding a higher concentration of KCl to ABW results in a lower initial temperature and activation energy for the volatile phase of ABW. At the same time, a higher KCl concentration leads to an increased biochar yield; under single-factor conditions, a biochar yield of up to 35.81% can be achieved with an impregnation concentration of 15%. A lower KCl is more conducive to the pyrolysis reaction, with a lower activation energy throughout the devolatilization stage compared to raw ABW. Additionally, ABW treated with a low concentration of KCl results in a higher specific surface area and pore volume of the biochar. The maximum values are achieved when the KCl solution concentration is 5%, with a specific surface area of 4.2 m²/g and a pore volume of 0.00914 cm³/g. Based on these results, this paper explores the catalytic pyrolysis patterns of KCl on branch waste, providing theoretical guidance for the effective utilization of branch wood and the preparation process of biochar. Full article

After almost a century of global generational IQ test score gains, the Flynn effect has, in the past decades, been observed to show stagnation and reversals in several countries. Tentative evidence from academic achievement data has suggested that these trajectory changes may be rooted in a decreasing strength of the positive manifold of intelligence due to increasing ability differentiation and specialization in the general population. Here, we provide direct evidence for generational IQ test score and positive manifold strength changes based on IQ test standardization data from 1392 Austrian residents between 2005 and 2018. Our analyses revealed positive Flynn effects across all domains of the IQ test (Cohen’s d from 0.21 to 0.91) but a trend toward decreasing strength in the positive manifold of intelligence (R² from .908 to .892), though these changes were not statistically significant. Our results are consistent with the idea that increasingly inconsistent Flynn effect trajectories may be attributed to increasing ability differentiation and specialization in the general population over time. Full article

To effectively utilize industrial lignin, a large amount of waste produced by the pulp and paper industry, this paper primarily explores its potential as a substitute for coal-based reducing agents in the reduction of iron oxides. The weight change, phase change, and activation energy change during the reduction of iron oxide by industrial lignin were characterized using detection methods such as TG-DTG-DSC, XRD, and SEM. The results show that the maximum weight loss rate of industrial lignin reducing iron oxide is (4.52%·min⁻¹) > Lu’an anthracite (2.01%·min⁻¹) > Shenmu bituminous coal (1.57%·min⁻¹). The activation energy variation range during the reduction of Fe₂O₃ by industrial lignin, calculated using the Flynn–Wall–Ozawa (FWO) method, is 241.91~463.51 kJ·mol⁻¹, and the activation energy first decreased, then increased, then decreased slightly with the increase of conversion fraction. There is a coupling effect in the reduction of Fe₂O₃ by industrial lignin. Full article

Angiotensin II receptor antagonists are tetrazole derivatives used in the treatment of high blood pressure, and are also indicated for the treatment of heart failure (NYHA class II-IV). They are used alone or in combination with other classes of antihypertensives or diuretics for the effective management of high blood pressure. In this study, we aim to evaluate the thermal stability and degradation kinetics for the principal compounds used in therapy from this class, namely telmisartan, valsartan, olmesartan medoxomil, and losartan potassium. To obtain the thermoanalytical data for the kinetic investigations, the TG and DTG curves were registered at five different heating rates (β = 2, 4, 6, 8, and 10 °C min⁻¹). The kinetic methods used were a preliminary ASTM E698 method and two isoconversional methods: Flynn–Wall–Ozawa and Friedman. For each molecule, the results showed complex decomposition processes consisting of complex reaction sequences. Full article

The recent release of the WAIS-5, a decade and a half after its predecessor, the WAIS-IV, raises immediate questions about the Flynn effect (FE). Does the traditional FE of points per decade in the U.S. for children and adults, identified for the Full Scale IQs of all Wechsler scales and for other global IQ scores as well, persist into the 2020s? The WAIS-5 Technical and Interpretive Manual provides two counterbalanced validity studies that address the Flynn effect directly—N = 186 adolescents and adults (16–90 years, mean age = 47.8) tested on the WAIS-IV and WAIS-5; and N = 98 16-year-olds tested on the WISC-V and WAIS-5. The FE is incorporated into the diagnostic criteria for intellectual disabilities by the American Association on Intellectual and Developmental Disabilities (AAIDD), by DSM-5-TR, and in capital punishment cases. The unexpected result of the two counterbalanced studies was a reduction in the Flynn effect from the expected value of 3 IQ points to 1.2 points. These findings raise interesting questions regarding whether the three point adjustment to FSIQs should be continued for intellectual disability diagnosis and whether the federal courts should rethink its guidelines for capital punishment cases and other instances of high stakes decision-making. Limitations include a lack of generalization to children, the impact of the practice effects, and a small sample size. Full article

Emerging pharmaceutical pollutants like ciprofloxacin (CIP) and ibuprofen (IBU) are frequently detected in aquatic environments, posing risks to ecosystems and human health. Since pollutants rarely exist alone in the environment, understanding the thermal stability and degradation kinetics of these compounds, especially in mixtures, is crucial for developing effective removal strategies. This study therefore investigates the thermal stability and degradation kinetics of CIP and IBU, under different heating rates. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) were employed to examine the thermal behavior of these compounds individually and in mixture (CIP + IBU) at heating rates of 10, 20, and 30 °C/min. The kinetics of thermal degradation were analyzed using both model-fitting (Coats–Redfern (CR)) and model-free (Kissinger–Akahira–Sunose (KAS), Flynn–Wall–Ozawa (FWO), and Friedman (FR)) methods. The results showed distinct degradation patterns, with CIP decomposing between 280 and 550 °C and IBU between 152 and 350 °C, while the mixture exhibited multistep decomposition in the 157–500 °C range. The CR model indicated first-order kinetics as a better fit for the degradation (except for IBU). Furthermore, CIP exhibits higher thermal stability and activation energy compared to IBU, with the KAS model yielding activation energies of 58.09 kJ/mol for CIP, 11.37 kJ/mol for IBU, and 41.09 kJ/mol for CIP + IBU mixture. The CIP + IBU mixture generally showed intermediate thermal properties, suggesting synergistic and antagonistic interactions between the compounds. Thermodynamic parameters (ΔH°, ΔG°, ΔS°) were calculated, revealing non-spontaneous, endothermic processes for all samples (except in the FWO method) with a decrease in molecular disorder and positive ΔG° values across all models and heating rates. The study found that higher heating rates led to less thermodynamically favorable conditions for degradation. These findings provide important information concerning the thermal behavior of these pharmaceutical pollutants, which can inform strategies for their removal from the environment and the development of more effective waste-treatment processes. Full article

Thermogravimetric Analysis (TGA) serves a pivotal technique for evaluating the thermal behavior of Polyvinyl alcohol (PVA), a polymer extensively utilized in the production of fibers, films, and membranes. This paper targets the kinetics of PVA thermal degradation using high three heating rate range 20, 30, and 40 K min⁻¹. The kinetic study was performed using six model-free methods: Freidman (FR), Flynn-Wall-Qzawa (FWO), Kissinger-Akahira-Sunose (KAS), Starink (STK), Kissinger (K), and Vyazovkin (VY) for the determination of the activation energy (E_a). TGA showed two reaction stages: the main one at 550–750 K and the second with 700–810 K. But only the first step has been considered in calculating E_a. The average activation energy values for the conversion range (0.1–0.7) are between minimum 104 kJ mol⁻¹ by VY to maximum 199 kJ mol⁻¹ by FR. Model-fitting has been applied by combing Coats–Redfern (CR) with the master plot (Criado’s) to identify the most convenient reaction mechanism. E_a values gained by the above six models were very similar with the average value of (126 kJ mol⁻¹) by CR. The reaction order models-Second order (F2) was recommended as the best mechanism reaction for PVA pyrolysis. Mechanisms were confirmed by the compensation effect. Finally, (∆H, ∆G, and ∆S) parameters were presented and proved that the reaction is endothermic. Full article

Generational IQ test scores in the general population were observed to increase over time (i.e., the Flynn effect) across most of the 1900s. However, according to more recent reports, Flynn effect patterns have seemingly become less consistent. So far, most available evidence on this phenomenon has been categorized by drawing on the classic fluid vs. crystallized intelligence taxonomy. However, recent evidence suggests that subdomain-specific trajectories of IQ change may well be more complex. Here, we present evidence for cross-temporal changes in measurement-invariant figural reasoning tasks in three large-scale, population-representative samples of German secondary school students (total N = 19,474). Analyses revealed a consistent pattern of significant and meaningful declines in performance from 2012 to 2022. Results indicate a decrease in figural reasoning of 4.68 to 5.17 IQ points per decade (corresponding to small-to-medium effects, Cohen ds from 0.34 to 0.38). These findings may be interpreted as tentative evidence for a decreasing strength of the positive manifold of intelligence as a potential cause of the increasing number of recent reports about inconsistent IQ change trajectories. Full article

In this study, we have focused on studying the heterogenous degradation kinetics regarding the decomposition of the emergency contraceptive agent levonorgestrel (LNG), which is a second-generation synthetic progestogen that is the active component of the racemic mixture of norgestrel. The degradation processes of the active pharmaceutical ingredient (API) were compared with the ones obtained from a model system containing the API along with the excipients that are found in a commercialized pharmaceutical formulation in a mass ratio of 1:1 (LNGMIX), in order to observe if the excipients have a stabilizing or destabilizing effect on the degradation of this progestogen. To achieve this, the following investigational methods were used: FTIR (Fourier transform infrared) spectroscopy and thermal analysis (TG/DTG/DSC analysis). For the kinetic analysis, the data obtained from two main decomposition processes observed on the DTG curves were used and processed with a preliminary method, namely ASTM E698, and two isoconversional methods: Friedman and Flynn–Wall–Ozawa. The isoconversional study revealed that the decomposition mechanisms of both LNG and LNGMIX are complex, and the excipients have a stabilizing effect on the decomposition of the API in tablet. Full article

The coupled combustion of biomass and organic solid wastes including oil sludge has attracted much attention. Although the optimal mixing ratio of different coal types and biomass has been extensively studied, little attention has been paid to oil sludge that has undergone co-combustion. In this study, the combustion characteristics of blended fuel for coal, biomass and oil sludge under different mixing ratios are studied via a thermogravimetric test and differential thermal analysis. Kinetic analysis of tri-fuel is performed using the Flynn–Wall–Ozawa (FWO) and Dolye methods. The results show that the bituminous coal combustion process mainly involves the combustion of fixed carbon (236.0–382.0 °C). Wood pellet combustion (383.0–610.0 °C) has two processes involving the combustion of compound carbon and fixed carbon. Blending wood pellets effectively enhances combustion efficiency. Wood pellets from Korla (KOL) have the most obvious effect on reducing the ignition temperature. The blending combustion of bituminous coal (SC), wood pellets from Hutubi (HTB) and oil sludge (OS) have significant synergistic effects. As the OS mixing ratio increases from 10% to 20% with 45% HTB, T_i and T_h decrease from 354.9 and 514.3 °C to 269.8 and 452.7 °C, respectively. In addition, f(α) is [−ln(1 − α)]² for tri-fuel in most mixing ratios when α < 0.5, while f(α) becomes [−ln(1 − α)]³ at α > 0.5. At a high-HTB-level mixing ratio, increasing the OS content causes a decrease in activation energy to 35.87 kJ mol⁻¹. The moderate blending of oil sludge improves the pre-finger factor and the combustion performance. Full article