Search Results (242)

In the context of advancing sustainable energy solutions, this paper provides a detailed modelling study of the process integration of biomass gasification to produce syngas and subsequent methanation for methane production. The process is assumed to take place in a circulating fluidised bed and three adiabatic fixed-bed reactors. To address the low H₂/CO ratio of syngas produced from biomass gasification using air, three pre-methanation scenarios were evaluated: water gas shift reaction (scenario 1), H₂ addition through Power-to-Gas (scenario 2), and splitting syngas into pure H₂ and CO and then recombining them in a 3:1 ratio (scenario 3). The findings reveal that each scenario presents a unique balance of efficiency, decarbonisation potential, and technological integration. Scenario 2 achieves the highest overall efficiency at 62%, highlighting the importance of integrating renewable electricity into the methane industry. Scenario 1, which incorporates WGS and CO₂ capture, offers an environmentally friendly solution with an overall efficiency of 59%. In contrast, Scenario 3, involving H₂/CO separation and recombination, achieves only 44.4% efficiency due to energy losses during separation, despite its operational simplicity. Methane yields were highest in Scenario 1, while Scenario 2 offers the most significant potential for integration with decarbonised power systems. The model was validated using published data and feedstock characteristics from experimental work and industrial projects. The results showed good agreement and supported the accuracy of the simulation in reflecting realistic biomass processing for methane production. Full article

Critical metals such as rare earth elements (REEs) are primarily associated with silicates and aluminosilicates in coal fly ash, resulting in poor REE recovery. Silicate bacteria can decompose silicate minerals and release silicon, but their impact on REE extraction remains unclear. In this study, two coal fly ash samples with different origins and combustion methods were bioleached by Paenibacillus mucilaginosus, and the effects of bio-desilication on REE leaching were examined. First, the optimal bio-desilication conditions were determined as a pulp density of 1%, an initial pH of 7.0 and an initial cell concentration OD₆₀₀ = 0.2. Compared to circulating fluidized bed (CFB) coal fly ash, silicon in pulverized coal furnace (PCF) coal fly ash was more difficult to dissolve by P. mucilaginosus. After bio-desilication, the acid leaching rate of REEs improved by 8–15% for CFB coal fly ash but only 4–5% for the PCF sample. Further investigation found that the surface turned rough and the specific surface area of coal fly ash increased after bio-desilication, which are conducive to REE extraction. Additionally, there was more quartz and mullite in PCF coal fly ash, which are more resistant to biological corrosion than amorphous silicate. The results demonstrate that bio-desilication can improve REE recovery, providing new perspectives for the low-cost green utilization of coal fly ash. Full article

This study investigates the potential of using downgraded chestnuts, which are unsuitable for commercial sale, from five distinct Greek regions to produce chestnut flour and formulate gluten-free biscuits. Chestnuts were dried and milled into flour, which was then used as the sole flour ingredient in the biscuit formulation, in order to assess its nutritional and functional contribution. The moisture, lipid, protein, and ash contents were analyzed in chestnut flour samples, which showed significant regional differences. Chestnut flour biscuits (CFB) were compared to wheat flour biscuits (WFB). CFB exhibited significantly higher ash content (3.01% compared to 0.94% in WFB) and greater antioxidant capacity, with DPPH scavenging activity reaching 70.83%, as opposed to 61.67% in WFB, while maintaining similar moisture and lipid levels. Although CFB showed slightly lower protein content, the elevated mineral and phenolic compound levels contributed to its functional value. These findings indicate that downgraded chestnuts can be upcycled into gluten-free bakery products with improved functional characteristics. Given their antioxidant activity and mineral content, chestnut flour biscuits may serve as a valuable option for gluten-free diets, supporting circular economy principles and reducing food waste. Full article

Over recent decades, phase-change materials (PCMs) have gained prominence as latent-heat thermal energy storage systems in building envelopes because of their high energy density. However, only PCMs that complete a full daily charge–discharge cycle can deliver meaningful energy and carbon-emission savings. This simulation study introduces a methodology that simultaneously optimizes PCM integration for storage efficiency, indoor thermal comfort, and energy savings. Two new indicators are proposed: overall storage efficiency (EC_n), which consolidates heating and cooling-efficiency ratios into a single value, and the performance factor (PF), which quantifies the PCM’s effectiveness in maintaining thermal comfort. Using EnergyPlus v8.9 coupled with DesignBuilder, a residential ASHRAE 90.1 mid-rise apartment was modeled in six warm-temperate (Cfb) European cities for the summer period from June 1 to August 31. Four paraffin PCMs (RT-22/25/28/31 HC, 20 mm thickness) were tested under natural and controlled ventilation strategies, with windows opening 50% when outdoor air was at least 2 °C cooler than indoors. Simulation outputs were validated against experimental cubicle data, yielding a mean absolute indoor temperature error ≤ 4.5%, well within the ±5% tolerance commonly accepted for building thermal simulations. The optimum configuration—RT-25 HC with temperature-controlled ventilation—achieved PF = 1.0 (100% comfort compliance) in all six cities and delivered summer cooling-energy savings of up to 3376 kWh in Paris, the highest among the locations studied. Carbon-emission reductions reached 2254 kg CO₂-e year⁻¹, and static payback periods remained below the assumed 50-year building life at a per kg PCM cost of USD 1. The EC_n–PF framework, therefore, provides a transparent basis for selecting cost-effective, energy-efficient, and low-carbon PCM solutions in warm-temperate buildings. Full article

A novel modified oyster shell (MOS-800) was developed to enhance phosphorus sequestration and recovery from wastewater. Approximately 33.3% of phosphate was eliminated by the MOS-800, which also exhibited excellent pH regulation capabilities. In semicontinuous tests, a synergistic phosphorus separation was achieved through the coupling process of CaCl₂/MOS-800 and a circulating fluidized bed (CFB), resulting in an 86.5% phosphate separation. In continuous flow experiments, phosphorus elimination reached 98.2%. Material characterization revealed that hydroxyapatite (HAP) was the primary component of the crystallized products. Additionally, MOS-800 released 506.5–572.2 mg/g Ca²⁺ and 98.1 mg/g OH⁻. A four-stage heterogeneous crystallization mechanism was proposed for the coupling process. In the first stage, Ca²⁺ quickly reacted with phosphate to form Ca-P ion clusters, etc. In the second stage, these clusters packed randomly to form spherical amorphous calcium phosphate (ACP). In the third stage, the ACP spheres were transformed and rearranged into sheet-like HAP crystallites, Finally, in the fourth stage, the HAP crystallites aggregated on the surface of crystal seeds, also with the addition of crystal seeds and undissolved MOS-800, potentially catalyzing the heterogeneous crystallization. These findings suggest that the CaCl₂/MOS-800/CFB system is a promising technique for phosphate recovery from wastewater. Full article

Based on the low-carbon transition needs of coal-fired boilers, this study conducted industrial trials of direct biomass co-firing on a 620 t/h high-temperature, high-pressure circulating fluidized bed (CFB) boiler, gradually increasing the co-firing ratio. It used compressed biomass pellets, achieving stable 20 wt% (weight percent) operation. By analyzing boiler parameters and post-shutdown samples, the comprehensive impact of biomass co-firing on the boiler system was assessed. The results indicate that biomass pellets were blended with coal at the last conveyor belt section before the furnace, successfully ensuring operational continuity during co-firing. Further, co-firing biomass up rates of to 20 wt% do not significantly impact the fuel combustion efficiency (gaseous and solid phases) or boiler thermal efficiency and also have positive effects in reducing the bottom ash and SO_x and NO_x emissions and lowering the risk of low-temperature corrosion. The biomass co-firing slightly increases the combustion share in the dense phase zone and raises the bed temperature. The strong ash adhesion characteristics of the biomass were observed, which were overcome by increasing the ash blowing frequency. Under 20 wt% co-firing, the annual CO₂ emissions reductions can reach 130,000 tons. This study provides technical references and practical experience for the engineering application of direct biomass co-firing in industrial-scale CFB boilers. Full article

Sinusoidal Obstruction Syndrome/Veno-Occlusive Disease (SOS/VOD) is a severe complication of hematopoietic cell transplantation (HCT). Furthermore, emerging evidence suggests the potential role of complement activation and endothelial injury in SOS/VOD pathogenesis. In this study, we aimed to identify potential distinct pathogenic genetic variants between SOS/VOD and other endothelial injury syndromes following HCT, such as transplant-associated thrombotic microangiopathy (TA-TMA). For this aim, genomic DNA from 30 SOS/VOD patients and 30 controls with TA-TMA was analyzed. Using Next-Generation Sequencing (NGS), variants in complement-related genes (CFH, CFI, CFB, CFD, C3, CD55, C5, CD46, and thrombomodulin/THBD) and ADAMTS13 were examined. Out of 426 detected variants, 20 were classified as pathogenic. In SOS/VOD patients, variants were identified in ADAMTS13 (4), CFH (3), C3 (2), and CFB (1) genes. One of the variants has been recognized as the strongest genetic predictor of ADAMTS13 activity. Controls exhibited more variants in complement-related genes, particularly CFH, CFI, and C3. The genetic differences between SOS/VOD and TA-TMA highlight different pathogenic mechanisms, offering the potential for targeted risk assessment and therapy in HCT recipients. Full article

This study investigated the production, purification, and evaluation of a microbial metabolite with herbicidal activity produced by Fusarium fujikuroi via submerged fermentation. The purified compound (PC) was obtained through organic solvent extraction and chromatographic purification, and assessed in bioassays using Raphanus sativus and Triticum aestivum as bioindicator plants. A concentration of 23 mg mL⁻¹ completely inhibited seed germination in 96-well plate assays, while the crude extract (EXT) and cell-free broth (CFB) allowed radicle protrusion but resulted in abnormal seedlings with chlorosis and reduced growth. Mathematical models estimated that concentrations of 16.0 mg mL⁻¹ for radish and 0.9 mg mL⁻¹ for wheat were sufficient to suppress germination with the PC. In substrate experiments, the PC at 6.4 and 64.0 mg mL⁻¹ did not inhibit germination but caused anomalies in radish and significantly reduced wheat seedling growth. In naturally infested soil, the PC maintained phytotoxicity symptoms for 21 days, and after 28 days, a concentration of 64.0 mg mL⁻¹ significantly reduced radish seedling growth. The results highlight the potential of the compound as a bioherbicide. Full article

Background: Cervical foraminal bony stenosis (CFBS) is a common degenerative spinal condition that causes radicular pain and functional impairment in the upper extremities. Accurate and objective diagnosis of CFBS remains challenging due to the absence of standardized morphometric criteria. This study aimed to determine an optimal cut-off value for the cervical foraminal cross-sectional area (CFCSA) at the C5/6 level as a diagnostic indicator of CFBS. Methods: We conducted a retrospective case-control study including 154 patients aged 50 years or older with clinically and radiologically confirmed CFBS and 150 age-matched asymptomatic controls. Cervical spine magnetic resonance imaging (MRI) was performed in all subjects and CFCSA measurements were obtained from sagittal T2-weighted images using a standardized protocol. Group differences were analyzed using t-tests and diagnostic performance was assessed using receiver operating characteristic (ROC) curve analysis. Results: The mean CFCSA was significantly lower in the CFBS group (25.65 ± 7.19 mm²) compared to the control group (43.00 ± 8.38 mm²; p < 0.001). ROC analysis identified a CFCSA threshold of 33.02 mm² as the optimal cut-off point for predicting CFBS, yielding a sensitivity of 86.4%, a specificity of 86.7%, and an area under the curve (AUC) of 0.94 (95% CI: 0.91–0.96). Conclusions: These findings suggest that CFCSA is a robust and reproducible morphological parameter for evaluating foraminal stenosis. The proposed cut-off may enhance diagnostic accuracy and aid in clinical decision-making for patients presenting with C6 radiculopathy. However, given this study’s retrospective, single-center design, further validation through multicenter, prospective studies across multiple cervical levels is warranted. Full article

With the increasing global focus on sustainable development, circulating fluidized bed (CFB) boilers, as highly efficient and low-pollution combustion equipment, play an important role in energy production and environmental protection. However, the combustion efficiency and emission control of CFB boilers still face challenges, and there is an urgent need for multi-objective optimization through advanced technologies to support the goal of sustainable development. This study proposes an intelligent framework integrating Bidirectional Temporal Convolutional Network (BiTCN) and Hybrid Dung Beetle Optimizer (HDBO) for multi-objective optimization of combustion efficiency and NOx/SO₂ emissions in CFB boilers. The BiTCN model captures bidirectional temporal dependencies between dynamic parameters (e.g., air-coal ratio, bed temperature) and target variables through operational data analysis. Three key improvements are implemented in DBO: (1) Chaotic initialization via sequential pattern mining (SPM) enhances population diversity and spatial coverage; (2) The osprey optimization algorithm (OOA) hunting mechanism replaces the original rolling update strategy, improving global exploration; (3) t-Distribution perturbation is applied to foraging beetles in later iterations, leveraging its “sharp peak and thick tail” characteristics to dynamically balance exploitation and exploration. Experimental results demonstrate 0.5–1% combustion efficiency improvement and 15.1%/30% reductions in NOx/SO₂ emissions for a typical CFB boiler. Full article

Background: The patient-reported outcomes (PROs) of sacituzumab govitecan (SG) were compared with chemotherapy using two phase 3 trials (TROPiCS-02, EVER-132-002) involving patients with HR+/HER2− locally recurrent inoperable or metastatic breast cancer. Methods: A meta-analysis was performed to compare change from baseline (CFB) scores and time-to-deterioration (TTD) between SG and chemotherapy using EORTC QLQ-C30 and EQ-5D-5L VAS in the overall, prior CDK4/6i-treated, and fast-progressor populations. Results of CFB and TTD analyses were summarized using hazard ratio (HR) and mean difference measures. Results: Statistically significant improvement (p < 0.05) in CFB scores was observed with SG over chemotherapy in five EORTC QLQ-C30 domains: physical (mean difference: 2.64), role functioning (mean difference: 2.70), fatigue (mean difference: −2.51), pain (mean difference: −3.25) and dyspnea (mean difference: −3.27), and EQ-5D-5L VAS (mean difference: 1.58). In the overall population, longer TTD (p < 0.05) was observed with SG versus chemotherapy on six domains of EORTC QLQ-C30: GHS/QoL (HR: 0.76), physical (HR: 0.72), emotional functioning (HR: 0.73), fatigue (HR: 0.80), pain (HR: 0.82), and dyspnea (HR: 0.71). Results from EORTC QLQ-C30 domains were mostly consistent among the overall, prior CDK4/6i treated and fast-progressor populations. SG demonstrated longer TTD (p < 0.05) over chemotherapy for EQ-5D-5L-VAS across all studied populations (HR range: 0.63–0.69). PROs significantly worsened with SG in the domains of diarrhea and nausea and vomiting (commonly reported adverse events of SG, manageable by following established guidelines). Conclusions: SG significantly improved PROs versus chemotherapy for several subdomains of EORTC QLQ-C30 and EQ-5D-5L-VAS. The consistency of these results in the overall population and subgroups supports the generalizability of the meta-analytic evidence and reinforces the PRO benefits associated with SG versus chemotherapy. Full article

Biomass fluidized bed gasification technology has attracted significant attention due to its high efficiency and clean energy conversion capabilities. However, its industrial application has been limited by insufficient technological maturity. This paper systematically reviews the research progress on biomass fluidized bed gasification characteristics; compares the applicability of bubbling fluidized beds (BFBs), circulating fluidized beds (CFBs), and dual fluidized beds (DFBs); and highlights the comprehensive advantages of CFBs in large-scale production and tar control. The gas–solid flow characteristics within CFB reactors are highly complex, with factors such as fluidization velocity, gas–solid mixing homogeneity, gas residence time, and particle size distribution directly affecting syngas composition. However, experimental studies have predominantly focused on small-scale setups, failing to characterize the impact of flow dynamics on gasification reactions. Therefore, numerical simulation has become essential for in-depth exploration. Additionally, this study analyzes the influence of different gasification agents (air, oxygen-enriched, oxygen–steam, etc.) on syngas quality. The results demonstrate that oxygen–steam gasification eliminates nitrogen dilution, optimizes reaction kinetics, and significantly enhances syngas quality and hydrogen yield, providing favorable conditions for downstream processes such as green methanol synthesis. Based on the current research landscape, this paper employs numerical simulation to investigate oxygen–steam CFB gasification at a pilot scale (500 kg/h biomass throughput). The results reveal that under conditions of O₂/H₂O = 0.25 and 800 °C, the syngas H₂ volume fraction reaches 43.7%, with a carbon conversion rate exceeding 90%. These findings provide theoretical support for the industrial application of oxygen–steam CFB gasification technology. Full article

The climate of the Hungarian lowland (Central European region, Pannonian Plain area) can be characterized by Köppen’s Cfb climate formula (C—warm temperate, f—no seasonality in the annual course of precipitation, b—warm summer). This characterization does not provide information about the human thermal load and thermal perception. The aim of this work is to fill this gap. We focused on the morning, clear-sky periods of the day, when the heat supply provided by the weather is the lowest. The human thermal load of clear-sky mornings was estimated using the new clothing thermal resistance–operative temperature (r_cl–T_o) model. In contrast to IREQ-type (Required Clothing Insulation) models, this model parametrizes the total metabolic heat flux density (M) as a function of anthropometric data (body mass, height, sex, age). In the simulations, the selected persons walk (M values range between 135 and 170 W m⁻²) or stand (M values range between 84 and 96 W m⁻²), while their body mass index (BMI) varies between 25 and 37 kg m⁻². The following main results should be highlighted: (1) Human activity has a significant impact on r_cl; it ranges between 0 and 3.5 clo during walking and between 0 and 6.7 clo during standing. (2) The interpersonal variability of r_cl increases with increasing heat deficit accordingly; in the case of a walking person, it is around 1 clo in the largest heat deficits and around 0 clo in the smallest heat deficits. Since, in general, anticyclones increase the heat deficit while cyclones reduce it, extreme thermal loads are associated with anticyclones. It should be mentioned that the interpersonal variability of the human thermal load cannot be analyzed without databases containing people’s anthropometric data. Full article

The exponential growth of interconnected devices in the Internet of Things (IoT) has raised significant concerns about data security, especially when transmitting sensitive information over wireless channels. Traditional encryption techniques often fail to meet the energy and processing constraints of resource-limited IoT devices. This paper proposes a novel hybrid security framework that integrates chaotic encryption and steganography to enhance confidentiality, integrity, and resilience in audio communication. Chaotic systems generate unpredictable keys for strong encryption, while steganography conceals the existence of sensitive data within audio signals, adding a covert layer of protection. The proposed approach is evaluated within an Orthogonal Frequency Division Multiplexing (OFDM)-based wireless communication system, widely recognized for its robustness against interference and channel impairments. By combining secure encryption with a practical transmission scheme, this work demonstrates the effectiveness of the proposed hybrid method in realistic IoT environments, achieving high performance in terms of signal integrity, security, and resistance to noise. Simulation results indicate that the OFDM system incorporating chaotic algorithm modes alongside steganography outperforms the chaotic algorithm alone, particularly at higher Eb/No values. Notably, with DCT-OFDM, the chaotic-CFB based on steganography algorithm achieves a performance gain of approximately 30 dB compared to FFT-OFDM and DWT-based systems at Eb/No = 8 dB. These findings suggest that steganography plays a crucial role in enhancing secure transmission, offering greater signal deviation, reduced correlation, a more uniform histogram, and increased resistance to noise, especially in high BER scenarios. This highlights the potential of hybrid cryptographic-steganographic methods in safeguarding sensitive audio information within IoT networks and provides a foundation for future advancements in secure IoT communication systems. Full article

The post-combustion technology of circulating fluidized beds (CFBs) can largely reduce the emission of nitrogen oxides (NO_x) in the process of combustion, significantly reducing the removal cost of NO_x. To explore the potential of the combined removal of NO_x and SO₂ emissions under post-combustion technology, experiments were conducted on a 0.1 MWth circulating fluidized bed test platform. This paper focuses on the effect of temperature in CFB with limestone addition on NO_x and SO₂ emissions under post-combustion technology combined with sorbent injection into the furnace. The low-cost combined removal of NO_x and SO₂ can be realized by denitrification in the furnace and through secondary desulfurization in the furnace and post-combustion chamber. In the optimized experimental condition, with combustion temperatures at 845 °C and sorbent addition in the furnace under post-combustion, the emission of NO_x can be reduced to 47.10 mg/Nm³(@6%O₂), and meanwhile, the emission of SO₂ can be reduced to 92.09 mg/Nm³. Sulfur removal efficiency is higher under lower temperatures in a weakly reducing atmosphere. The reaction of sulfur fixation occurred in the post-combustion chamber and caused the particle size of fly ashes at the tail flue to become bigger and the sulfur content in the fly ash at the tail flue to increase. At 845–905 °C, the combustion temperature had a bigger effect on the SO₂ emission than the NO_x with sorbent addition in the furnace under post-combustion. Full article