Search Results (2,017)

Photovoltaic–thermal (PVT) collectors coupled to thermochemical energy storage (TCES) can turn intermittent low-grade solar heat into a dispatchable service, but solar intermittency poses a closed-loop control problem. A companion study established the feedback-only lower bound: a 937 kJ accumulated exergy-delivery-deficit benchmark under optimally tuned proportional–integral–derivative (PID) flow control. The corresponding upper bound is quantified here by means of a deliberately idealised search-based predictive controller that, at each 10 s step, enumerates 51 candidate pump rates, predicts the reactor-inlet temperature by a single forward-Euler step, and is granted perfect future irradiance. On the experimentally validated shared plant (matched to the companion baseline), against an optimally tuned PID, the perfect-foresight advantage is marginal: +0.96% daily exergy on synthetic days and +0.07–0.24% on two measured Walailak University monsoon days, all controllers tracking within 6–13 K on the measured days. Under tropical-monsoon irradiance, the 95 °C desorption setpoint is rarely sustained, so the delivered exergy is nearly controller-independent: the perfect-foresight upper bound lies just above the feedback-only lower bound, and together the two results bracket the exergy envelope available to any flow-rate controller of this system. A horizon sweep localises the bottleneck to internal-model fidelity, not anticipation depth. The eight-node plant is validated against measured module temperature (root-mean-square error 3.5 °C, coefficient of determination R² = 0.89) and a copper-tube PVT prototype (1.5 °C; peak hot water up to 79 °C). The central contribution is therefore a rigorously defined, experimentally grounded upper bound showing that, at this scale and latitude, deployability rather than anticipation is the effective design lever. Full article

This study reports the synthesis and comprehensive characterization of a novel 5% cadmium-doped cerium oxide/reduced graphene oxide (5% Cd-CeO₂/rGO) nanocomposite for the enhanced visible-light-driven photocatalytic degradation of methyl orange (MO). The nanocomposite was prepared using a simple co-precipitation method followed by thermal reduction, which integrates the excellent electron-transport properties of reduced graphene oxide (rGO) with the oxygen-vacancy-rich characteristics of Cd-doped CeO₂, resulting in improved photocatalytic performance. The successful synthesis of the nanocomposite and the direct interaction between the rGO sheets and ultrafine CeO₂ nanoparticles were verified through structural and morphological analyses using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, Transmission Electron Microscopy (TEM), and Scanning Electron Microscopy (SEM). XPS results indicated an increase in the Ce³⁺ concentration and oxygen vacancy density after Cd doping and rGO incorporation, both of which play a crucial role in enhancing photocatalytic activity. Under visible-light irradiation, the 5% Cd-CeO₂/rGO nanocomposite exhibited substantially higher photocatalytic activity and methyl orange (MO) degradation efficiency than pristine CeO₂ and reduced graphene oxide (rGO). The improved photocatalytic performance demonstrates the beneficial role of combining metal-ion doping with conductive carbon supports to facilitate charge separation and electron transport in semiconductor photocatalysts. The developed nanocomposite also shows promising potential for the design of next-generation semiconductor-based materials for photocatalytic, energy conversion, and optoelectronic applications. Full article

Five studies are frequently cited as experimental evidence that photobiomodulation (PBM) may stimulate tumour growth or produce phototoxicity, contributing to a documented barrier to clinical adoption in oncology. We reappraise these studies against their own reported dosimetry. None characterised the spatial power distribution of its beam. Each was assessed for arithmetic consistency, beam profile, device category, and biological-model appropriateness, and re-examined against the Arrhenius framework for thermal damage. In four of the five, the exposures delivered lay outside the therapeutic photobiological window on the authors’ own stated parameters: surface temperatures of 55 °C and, in places, 71 °C, with injury the original authors describe as coagulation and necrosis extending to paralysis and death; irradiances approximately 25 times those used clinically; and, in one case, parameters the authors themselves describe as high. The fifth, a xenograft study, used a dose within the therapeutic range, but its immunodeficient host cannot express the immune-mediated response at issue. A sixth study, from the same group and using the same device as one of the five but operated at a therapeutic irradiance, is included as an internal control and reported therapeutic benefit. Injury in these regimes is best understood as oxygen-dependent, with temperature acting as a sensitising variable and as a marker of the regime rather than as the proximate cause, a reading supported by the original authors’ own helium-substitution, cooling and heated-probe controls. We outline a two-tier mechanistic framework, in which correctly dosed PBM may engage systemic anti-tumour immunity, as a hypothesis for prospective testing rather than as a finding of this analysis. None of these studies provides dosimetrically secure evidence of a hazard from therapeutic-range PBM; equally, the absence of such evidence is not a demonstration of safety. Beam-profile reporting should become standard in PBM oncology research. Full article

Accurately predicting high-energy laser propagation toward fast-moving aerial targets is not straightforward, since the slant range, elevation angle, atmospheric path, accumulated turbulence, and thermal blooming all change along with target motion. Because of this coupled evolution, fixed-path or quasi-static models can hardly describe, in a complete way, the time-varying loss of beam transmission and the weakening of energy concentration. To address this problem, this paper builds on established wave-optics propagation methods to develop a dynamic multi-physics framework for high-speed moving-target engagements. The central idea is to rebuild the propagation environment at every time step according to the instantaneous target position so that the optical path can be linked with height-dependent extinction, refractive-index structure, and absorption profiles; meanwhile, relative motion is represented as an effective transverse sweeping velocity, which helps reduce the accumulation effect of thermal blooming. Based on a unified split-step Fourier method, the model combines Beer–Lambert path attenuation, Kolmogorov-spectrum multilayer phase screens, and thermal-blooming phase modulation, yielding time-resolved indicators such as transmittance, received power, peak irradiance, Strehl ratio, scintillation index, pointing error, and beam-quality factor. Simulation results show that, in a 500 m static horizontal path, the attenuation module reduces to the Beer–Lambert solution, with the maximum relative error kept below ${10}^{-14}$; the turbulence phase-screen implementation is validated against the absolute Kolmogorov prediction. Over the resolved inertial interval, the ensemble-averaged structure function yields a fitted exponent $p_{\mathrm{f}\mathrm{i}\mathrm{t}}=1.671$ (theoretical: $5/3=1.667$) and a relative normalization error of $2.5\mathrm{\%}$, confirming that the generated screens reproduce both the Kolmogorov scaling and the prescribed turbulence strength. For a 1.064 μm, 2 kW Gaussian beam propagating over a 50 s trajectory of about 8 km, when the target speed increases from 0 to 300 m/s, the thermal-blooming-related beam-quality factor decreases from roughly 1.8 to 1.2, which indicates that dynamic geometry, turbulence, attenuation, and thermal blooming need to be considered together when evaluating laser propagation performance. Full article

The selection of georeferenced meteorological databases is a critical technical and financial factor in photovoltaic (PV) system sizing. This study evaluates how database choice affects PV generation estimates and economic feasibility by combining bibliometric screening, technical validation, financial indicators, and multicriteria analysis. A bibliometric review of 5658 documents indexed in Scopus and Web of Science supports the selection of seven databases, compared across ten Brazilian locations. PV generation is estimated using both a simplified sizing approach and a higher-temporal-resolution model based on hourly irradiance, ambient temperature, and module thermal coefficients, enabling comparison with measured generation in a three-year case study in João Pessoa. Performance is assessed using MAE, MAPE, RMSE, $R^2$, NPV, payback and the Analytic Hierarchy Process. Under the adopted PV model and AHP weighting structure, NASA POWER shows the strongest overall multicriteria performance in the analyzed Brazilian sample, ranking first in seven locations. Database choice causes variations of up to 4.70 years in payback and BRL 105,709.36 in NPV, equivalent to USD 21,082.84 at the 22 May 2026 exchange rate. The simplified CRESESB-based method overestimates annual generation by 6.79–12.64%, whereas NASA POWER reaches a best annual deviation of $-1.66\%$ in 2024. Full article

A homogeneous photocatalyst on a stable substrate is required for photocatalytic reactors in wastewater treatment. ZnO films were synthesized on stainless steel prepared by the spray pyrolysis technique at different deposition temperatures (350 to 500 °C in steps of 50 °C). Scanning electron microscopy showed microflowers formed by nanopetals with an average size of 2 μm. The ZnO wurtzite structure and its defects were studied by Raman spectroscopy, X-ray diffraction, diffuse reflectance, and photoluminescence spectroscopy. A deposition temperature of 400 °C was chosen due to the presence of a higher number of vibrational modes, better distribution of microflowers, smaller crystallite size and a higher number of defects than the other options. Lanthanides were incorporated into ZnO by solution spraying, and then thermal treatment was performed at 600 °C. The photocatalytic evaluation of ZnO showed the best photocatalytic activity under UV light at 365 nm with a 69.34% degradation efficiency at 120 min. Photocatalytic activity toward methylene blue degradation was enhanced in ZnO:Ce³⁺ (2 and 4 atom%) and ZnO:Nd³⁺ (0.05 and 2 atom%) samples, achieving degradation efficiencies above 90% within 30 min of UV–visible light irradiation. Full article

Long-term sugarcane monoculture triggers severe continuous cropping obstacles accompanied by notable soil microecological degradation, including nutrient immobilization, soil acidification, salinization and microbial community imbalance. Physical soil remediation via industrial microwave irradiation represents a promising approach to alleviate soil degradation. Nevertheless, the interactive variations in soil structure, fertility and microbial communities under gradient 915 MHz industrial microwave irradiation remain poorly understood. This study aimed to clarify the correlations among physicochemical properties, microbial structure and functional genes of sugarcane continuous cropping soil under microwave thermal regulation. A continuous 915 MHz microwave device with power gradients (0, 2, 4, 6, 8 kW) and a fixed irradiation duration of 10 min was adopted. Soil samples were incubated for 0, 15 and 30 weeks for comprehensive parameter determination. The results demonstrated that appropriate microwave power exerted positive regulatory effects on soil thermal intensity, aggregate disruption and microbial succession. Soil organic matter (SOM) and pH were key factors modulating the distribution of beneficial and pathogenic microorganisms. The 4 kW treatment disintegrated compact soil aggregates, activated mineral-bound nutrients, relieved soil acidification and salinization, and upregulated genes responsible for nutrient mineralization and antifungal metabolism to sustain high abundances of partial biocontrol fungi. In contrast, high-power treatments (6 kW and 8 kW) induced substantial early-stage SOM loss, reduced soil pH and aggravated salinization in the late incubation stage, thereby inhibiting symbiotic beneficial fungi. Collectively, 4 kW was the optimal microwave parameter in this study to coordinate soil structural, nutritional and microecological balance. This study provides a theoretical basis and technical guidance for the green remediation of soil plagued by sugarcane continuous cropping obstacles. Full article

As survival for cancer patients improves, the incidence of brain metastases has risen. This is likely due to improved systemic disease control, increased diligence in surveillance imaging in high-risk pathologies, improved neuro-imaging techniques and increased systemic screening for clinical trial enrollment. While there are well-established treatments for brain metastases, many patients will experience recurrence after definitive treatment. The management of these recurrent lesions is not well established and often varies on a per-patient basis, owing to the clinical complexity and variety of these patients. Patients with recurrent brain metastases have surgical procedural options to achieve local tumor control, including laser interstitial thermal therapy (LITT) repeat open surgical resection with or without placement of intracavity brachytherapy. Repeat resection can offer rapid improvement in neurological symptoms, performance status, and potentially survival. LITT is less invasive than a standard craniotomy but offers a chance at directed local treatment while still obtaining tissue for diagnostic purposes and achieving acceptable survival outcomes. Further study is needed to determine the role of LITT for recurrent brain metastases, but it is a useful tool, particularly for patients with deep-seated lesions who may not tolerate a large surgery. Intracavitary brachytherapy allows for the immediate delivery of highly conformal radiation to the surgical bed with excellent local control and low rates of radiation necrosis, even in previously irradiated patients. The decision regarding which of the above to employ for recurrent brain metastases will vary on a case-by-case basis, and further studies are needed to standardize their use for this growing problem. Full article

Water hyacinth leaves (WHL) are an inexpensive renewable fuel resource that can be employed for energy creation through hydrolysis of simple fermentable reducing sugars. In this work, a hybrid microwave irradiation (MWI)–ternary deep eutectic solvent (TNDES) system involving choline chloride (ChCl) as a hydrogen bond acceptor (HBA), triethanolamine (TEOA) as an amine-based hydrogen bond donor (HBD), monoethylene glycol (MEG), diethylene glycol (DEG), or triethylene glycol (TEG) as polyol-based HBD components was employed as an efficient and green material for pretreatment of WHL for further transformation of the polysaccharide portion. The results showed that hybrid MWI/TNDES (ChCl-TEOA-MEG, ChCl-TEOA-DEG, and ChCl-TEOA-TEG) pretreatments were very efficient for lignin removal from WHL, with efficacy ranging from 80.4 ± 3.2 to 87.7 ± 3.8% compared with pretreatment using hybrid MWI/binary NDES (ChCl-TEOA) (75.6 ± 2.4%). The higher efficacy of the hybrid MWI/TNDES pretreatment was attributed to the impacts of MWI on extracting biological materials and the lower viscosity, higher pH, and lower density associated with the TNDESs. The results indicate that WHL pretreated using hybrid MWI and ChCl-TEOA-MEG, ChCl-TEOA-DEG, and ChCl-TEOA-TEG resulted in significantly boosting cellulose digestibility (4–5 times that of pristine WHL and 1.5 times that of hybrid MWI/ChCl-TEOA-treated WHL). The effect of MWI/TNDES pretreatment was confirmed by scanning electron microscope (SEM) pictures, and lignin and hemicellulose elimination were clearly observed in Fourier transform infrared (FTIR) spectra. The lignin-rich material separated by the hybrid MWI/TNDES pretreatment was analyzed using thermogravimetric analysis (TGA) to obtain the thermal behaviors of this hybrid, pretreated WHL material. In our experimentation with hybrid MWI/TNDES, under optimum circumstances of MWI time of 6 min, MWI power of 300 W, and a temperature of 90 °C, 43–49 g/L TRS yield was achieved by acid-catalyzed hydrolysis employing WHL substrate after being optimized by the single-factor experiments (SFE) approach, while the optimized TRS for untreated WHL and hybrid MWI/binary ChCl-TEOA were estimated to be 12 g/L and 32 g/L, respectively. The hybrid MWI/ChCl-TEOA-TEG pretreated WHL resulted in a high ethanol yield (ca. 22.3 g/L) by Saccharomyces cerevisiae after 72 h of fermentation. This work demonstrates the potential of WHL as a sustainable bioenergy feedstock for bioethanol production in industrial biorefineries. The research establishes effective and green solvent pre-treatment materials and methods (based on hybrid MWI/TNDES) for the efficient removal of lignin and hemicellulose from WHL and cellulose recovery. In general, the research contributes to the development of environmentally friendly and cost-effective hybrid MWI/TNDES processes for WHL biomass conversion and offers strong evidence that hybrid MWI/TNDES processes represent a high-potential method for managing WHL infestations while generating useful products. Future studies should further investigate ways to enhance the efficacy of acid-catalyzed hydrolysis processes and assess the scalability of the technology for industrial applications. Full article

Solar-driven interfacial evaporation (SDIE) represents a highly promising technology for decentralized desalination and wastewater treatment, yet its practical industrial deployment is severely constrained by the intrinsic intermittency of natural solar irradiance and nocturnal salt crystallization. To smooth energy fluctuations and achieve all-weather, continuous freshwater output, integrating solid–liquid phase change materials (SLPCMs) into SDIE has evolved into a system-level paradigm shift driven by advanced spatiotemporal thermal-mass management. This review systematically summarizes recent breakthroughs in micro-to-macro structural engineering for phase-change-coupled SDIE systems. Spatially, advanced microscopic encapsulation strategies such as 3D matrices, core–shell architectures, and solid–solid transitions eradicate molten PCM leakage and reconstruct heat transfer networks, while macroscopic configurations involving sandwich structures and 3D directional channels realize functional zoning to maximize thermal localization. Temporally, the controlled nocturnal release of stored latent heat establishes a cross-timeline energy relay, sustaining dark evaporation and activating interfacial hydrodynamics via Marangoni convection and thermophoretic diffusion to prevent salt clogging under extreme conditions. Furthermore, cross-disciplinary integrations for water-electricity co-generation, targeted resource recovery, and environmental remediation are comprehensively discussed. Finally, critical engineering challenges regarding scalability, cost-effectiveness, and condensation system integration are addressed, offering forward-looking perspectives on coupling thermal storage with physical catalysis to transcend classical thermodynamic limits. Full article

This study presents a short-term outdoor comparison of mirror-glass and AISI 304 stainless-steel reflectors in parabolic trough collectors equipped with identical helical copper absorbers. Both configurations were operated simultaneously using the same collector geometry, fixed inclination angle, water-supply arrangement, measurement schedule, and instrumentation. Solar irradiance, inlet and outlet water temperatures, absorber temperature, and reflector temperature were recorded over three consecutive experimental days, namely 24–26 October 2025. The results were evaluated using temperature rise and time-dependent temperature output because the gravity-assisted system was not equipped with a flow meter or active flow-control device, preventing reliable calculation of useful heat gain and thermal efficiency. The descriptive results showed that the mirror-glass configuration produced a modestly higher overall temperature response and lower variation among the three daily mean values, although it did not outperform stainless steel at every measurement time or in every daily average. The observed difference is interpreted primarily in terms of the expected higher specular reflectivity and lower optical scattering of mirror glass, which can increase the solar radiation intercepted by the absorber. However, the conclusions are limited by the three-day testing period, absence of verified mass-flow data, lack of direct reflectivity measurements, and unquantified cosine losses associated with fixed operation without automatic tracking. The findings therefore provide configuration-specific guidance for reflector selection rather than a generalized ranking of collector performance. Full article

Decarbonizing the process heat required for chemical recycling would improve the environmental performance of plastic-waste valorization. This study presents an evaluation of the use of concentrated solar thermal energy as the reaction heat source for the hydrothermal depolymerization of post-consumer polyethylene terephthalate (PET). The solar-driven hydrothermal process (HTP-S) maintained an internal reactor temperature of approximately 200 °C for 4 h under favorable irradiance conditions. During the single experimental run, the system received 14.95 MJ of incident solar energy, whereas the conventional hydrothermal process (HTP-C) consumed 47.52 MJ of electricity per run. Starting from 1.2 g of PET, HTP-C and HTP-S produced 0.862 and 0.895 g of dry recovered solid, corresponding to recovered-solid yields of 71.7% and 74.5%, respectively. Fourier-transform infrared (FT-IR) spectroscopy, thermogravimetric analysis and derivative thermogravimetry (TGA/DTG), transmission electron microscopy (TEM), and X-ray diffraction (XRD) showed that the recovered solids exhibit physicochemical characteristics consistent with the formation of a crystalline terephthalic acid (TPA)-rich product. A cradle-to-gate life cycle assessment normalized to 1 kg of treated PET showed that cumulative energy demand decreased from 44,383.7 MJ for HTP-C to 7342.5 MJ for HTP-S, while global warming impacts decreased from 9717 to 1607 kg CO₂-eq. These results demonstrate the technical feasibility of coupling concentrated solar heating with hydrothermal PET depolymerization and identify reaction heating as the principal opportunity for reducing external electricity demand. These outcomes indicate that solar-powered hydrothermal processing provides a feasible pathway for PET recycling, reducing the environmental footprint. Full article

In silicone polymers, more than 90% of the main chain skeletons are linked by Si-O-Si bonds, with organic groups attached to the side chains and terminal groups. These polymers possess both organic and inorganic properties, exhibiting excellent resistance to high and low temperatures, good insulation, and weather resistance. They are widely used in aerospace, biomedical, electrical, transportation sectors and so on. Traditional methods for synthesizing silicones, such as carbon thermal reduction, have led to a sharp increase in global CO₂ emissions. Consequently, developing technologies for the efficient degradation and recycling of small siloxane molecules from waste silicone polymers has become a research hotspot in the silicone industry. This paper explores the technical selection and research progress of physical recycling methods such as mechanical grinding, ultrasonication, and irradiation, as well as chemical recycling methods including pyrolysis and acid–base catalysis, in the field of silicone recycling. This holds significant practical implications for achieving a closed-loop cycle for silicones and reducing carbon emissions in the industry. Full article

Green hydrogen (H₂) production is a pivotal element of Saudi Arabia’s Vision 2030. This study presents a comprehensive feasibility assessment of a high-efficiency H₂ production system integrating a photovoltaic (PV) array and a high-concentration photovoltaic (HCPV) system with a Proton Exchange Membrane (PEM) electrolyzer, specifically designed for harsh climatic conditions. To evaluate the system’s viability, a comprehensive simulation model was developed based on rigorously validated mathematical formulations. First, the performance of the PEM electrolyzer and the effectiveness of the cooling system were modeled using established electrochemical and thermal correlations derived from the peer-reviewed literature. Second, this model was applied to evaluate the system’s long-term energy yield and economic performance. Key economic metrics, including the levelized cost of H₂ (LCOH) and discounted payback period (DPBP), were calculated based on local solar irradiance data, followed by a sensitivity analysis to assess the economic robustness under varying market conditions. The results demonstrate that the proposed configuration is not only technically feasible—maintaining high efficiency despite harsh environmental conditions—but also economically viable, offering a competitive LCOH and attractive DPBP that align with the strategic objectives of Saudi Vision 2030. Full article

Semiconductor-based photocatalytic water splitting is a promising pathway for sustainable hydrogen production; however, the reported performance depends not only on the intrinsic properties of the photocatalyst but also on reactor configuration and operating conditions. This systematic technical review examines the interplay between nanostructured semiconductor photocatalysts and the principal engineering variables governing photocatalytic hydrogen evolution. Particular attention is given to particle size, morphology, surface area, defect density, heterojunction design, cocatalyst incorporation, aggregation, and catalyst immobilization, as well as their interaction with reactor geometry, optical path length, photon distribution, catalyst loading, working volume, pH, sacrificial agents, mixing, thermal control, gas purging, and product quantification. The reviewed evidence indicates that these material and reactor parameters jointly determine light absorption, charge-carrier separation and transfer, suspension turbidity, mass transport, catalyst recovery, stability, and the measured hydrogen evolution rate. Batch slurry reactors remain the most widely used laboratory configuration, whereas annular, flat-panel, microreactor, fixed-bed, continuous-flow, and photofluidized systems offer specific advantages for photon utilization, catalyst reuse, product removal, and scale-up. The review also emphasizes the need to distinguish overall water splitting from sacrificial-agent-assisted hydrogen evolution. Standardized reporting of photocatalyst properties, irradiance, spectral distribution, illuminated area, reactor dimensions, reaction atmosphere, and gas-analysis procedures is essential to improve reproducibility and enable reliable comparisons among nanostructured photocatalytic systems. Full article