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14 pages, 4225 KiB  
Article
DFT Investigation into Adsorption–Desorption Properties of Mg/Ni-Doped Calcium-Based Materials
by Wei Shi, Renwei Li, Xin Bao, Haifeng Yang and Dehao Kong
Crystals 2025, 15(8), 711; https://doi.org/10.3390/cryst15080711 - 3 Aug 2025
Viewed by 54
Abstract
Although concentrated solar power (CSP) coupled with calcium looping (CaL) offers a promising avenue for efficient thermal chemical energy storage, calcium-based sorbents suffer from accelerated structural degradation and decreased CO2 capture capacity during multiple cycles. This study used Density Functional Theory (DFT) [...] Read more.
Although concentrated solar power (CSP) coupled with calcium looping (CaL) offers a promising avenue for efficient thermal chemical energy storage, calcium-based sorbents suffer from accelerated structural degradation and decreased CO2 capture capacity during multiple cycles. This study used Density Functional Theory (DFT) calculations to investigate the mechanism by which Mg and Ni doping improves the adsorption/desorption performance of CaO. The DFT results indicate that Mg and Ni doping can effectively reduce the formation energy of oxygen vacancies on the CaO surface. Mg–Ni co-doping exhibits a significant synergistic effect, with the formation energy of oxygen vacancies reduced to 5.072 eV. Meanwhile, the O2− diffusion energy barrier in the co-doped system was reduced to 2.692 eV, significantly improving the ion transport efficiency. In terms of CO2 adsorption, Mg and Ni co-doping enhances the interaction between surface O atoms and CO2, increasing the adsorption energy to −1.703 eV and forming a more stable CO32− structure. For the desorption process, Mg and Ni co-doping restructured the CaCO3 surface structure, reducing the CO2 desorption energy barrier to 3.922 eV and significantly promoting carbonate decomposition. This work reveals, at the molecular level, how Mg and Ni doping optimizes adsorption–desorption in calcium-based materials, providing theoretical guidance for designing high-performance sorbents. Full article
(This article belongs to the Special Issue Performance and Processing of Metal Materials)
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18 pages, 5178 KiB  
Article
Quantification of Suspended Sediment Concentration Using Laboratory Experimental Data and Machine Learning Model
by Sathvik Reddy Nookala, Jennifer G. Duan, Kun Qi, Jason Pacheco and Sen He
Water 2025, 17(15), 2301; https://doi.org/10.3390/w17152301 - 2 Aug 2025
Viewed by 207
Abstract
Monitoring sediment concentration in water bodies is crucial for assessing water quality, ecosystems, and environmental health. However, physical sampling and sensor-based approaches are labor-intensive and unsuitable for large-scale, continuous monitoring. This study employs machine learning models to estimate suspended sediment concentration using images [...] Read more.
Monitoring sediment concentration in water bodies is crucial for assessing water quality, ecosystems, and environmental health. However, physical sampling and sensor-based approaches are labor-intensive and unsuitable for large-scale, continuous monitoring. This study employs machine learning models to estimate suspended sediment concentration using images captured in natural light, named RGB, and near-infrared (NIR) conditions. A controlled dataset of approximately 1300 images with SSC values ranging from 1000 mg/L to 150,000 mg/L was developed, incorporating temperature, time of image capture, and solar irradiance as additional features. Random forest regression and gradient boosting regression were trained on mean RGB values, red reflectance, time of captured, and temperature for natural light images, achieving up to 72.96% accuracy within a 30% relative error. In contrast, NIR images leveraged gray-level co-occurrence matrix texture features and temperature, reaching 83.08% accuracy. Comparative analysis showed that ensemble models outperformed deep learning models like Convolutional Neural Networks and Multi-Layer Perceptrons, which struggled with high-dimensional feature extraction. These findings suggest that using machine learning models and RGB and NIR imagery offers a scalable, non-invasive, and cost-effective way of sediment monitoring in support of water quality assessment and environmental management. Full article
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17 pages, 1522 KiB  
Article
Characterization of Solid Particulates to Be Used as Storage as Well as Heat Transfer Medium in Concentrated Solar Power Systems
by Rageh Saeed, Syed Noman Danish, Shaker Alaqel, Nader S. Saleh, Eldwin Djajadiwinata, Hany Al-Ansary, Abdelrahman El-Leathy, Abdulelah Alswaiyd, Zeyad Al-Suhaibani, Zeyad Almutairi and Sheldon Jeter
Appl. Sci. 2025, 15(15), 8566; https://doi.org/10.3390/app15158566 (registering DOI) - 1 Aug 2025
Viewed by 113
Abstract
Using solid particulates as a heat transfer medium for concentrated solar power (CSP) systems has many advantages, positioning them as a superior option compared with conventional heat transfer media such as steam, oil, air, and molten salt. However, a critical imperative lies in [...] Read more.
Using solid particulates as a heat transfer medium for concentrated solar power (CSP) systems has many advantages, positioning them as a superior option compared with conventional heat transfer media such as steam, oil, air, and molten salt. However, a critical imperative lies in the comprehensive evaluation of the properties of potential solid particulates intended for utilization under such extreme thermal conditions. This paper undertakes an exhaustive examination of both ambient and high-temperature thermophysical properties of four naturally occurring particulate materials, Riyadh white sand, Riyadh red sand, Saudi olivine sand, and US olivine sand, and one well-known engineered particulate material. The parameters under scrutiny encompass loose bulk density, tapped bulk density, real density, sintering temperature, and thermal conductivity. The results reveal that the theoretical density decreases with the increase in temperature. The bulk density of solid particulates depends strongly on the particulate size distribution, as well as on the compaction. The tapped bulk density was found to be larger than the loose density for all particulates, as expected. The sintering test proved that Riyadh white sand is sintered at the highest temperature and pressure, 1300 °C and 50 MPa, respectively. US olivine sand was solidified at 800 °C and melted at higher temperatures. This proves that US olivine sand is not suitable to be used as a thermal energy storage and heat transfer medium in high-temperature particle-based CSP systems. The experimental results of thermal diffusivity/conductivity reveal that, for all particulates, both properties decrease with the increase in temperature, and results up to 475.5 °C are reported. Full article
(This article belongs to the Section Applied Thermal Engineering)
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15 pages, 2314 KiB  
Article
Effect of the Nematic Liquid Crystal on the Dye Sensitized Solar Cell Performance
by Paweł Szubert and Stanisław A. Różański
Crystals 2025, 15(8), 705; https://doi.org/10.3390/cryst15080705 (registering DOI) - 31 Jul 2025
Viewed by 100
Abstract
The motivation for increasing the efficiency of renewable energy sources is the basic problem of ongoing research. Currently, intensive research is underway in technology based on the use of dye-sensitized solar cells (DSSCs). The aim of this work is to investigate the effect [...] Read more.
The motivation for increasing the efficiency of renewable energy sources is the basic problem of ongoing research. Currently, intensive research is underway in technology based on the use of dye-sensitized solar cells (DSSCs). The aim of this work is to investigate the effect of modifying the iodide electrolyte with liquid crystals (LCs) known for the self-organization of molecules into specific mesophases. The current–voltage (I-V) and power–voltage (P-V) characteristics were determined for the ruthenium-based dyes N3, Z907, and N719 to investigate the influence of their structure and concentration on the efficiency of DSSCs. The addition of a nematic LC of 4-n-pentyl-4-cyanobiphenyl (5CB) to the iodide electrolyte influences the I-V and P-V characteristics. A modification of the I-V characteristics was found, especially a change in the values of short circuit current (ISC) and open circuit voltage (VOC). The conversion efficiency for cells with modified electrolyte shows a complex dependence that first increases and then decreases with increasing LC concentration. It may be caused by the orientational interaction of LC molecules with the titanium dioxide (TiO2) layer on the photoanode. A too high concentration of LC may lead to a reduction in total ionic conductivity due to the insulating effect of the elongated polar molecules. Full article
(This article belongs to the Collection Liquid Crystals and Their Applications)
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11 pages, 2025 KiB  
Communication
Iodide Salt Surface Etching Reduces Energy Loss in CdTe Nanocrystal Solar Cells
by Jielin Huang, Xuyang Wang, Yilin Chen, Zhenyu Chen, Qiaochu Lin, Qichuan Huang and Donghuan Qin
Nanomaterials 2025, 15(15), 1180; https://doi.org/10.3390/nano15151180 - 31 Jul 2025
Viewed by 142
Abstract
CdTe nanocrystals (NCs) have emerged as a promising active layer for efficient thin-film solar cells due to their outstanding optical properties and simple processing techniques. However, the low hole concentration and high resistance in the CdTe NC active layer lead to high carrier [...] Read more.
CdTe nanocrystals (NCs) have emerged as a promising active layer for efficient thin-film solar cells due to their outstanding optical properties and simple processing techniques. However, the low hole concentration and high resistance in the CdTe NC active layer lead to high carrier recombination in the back contact. Herein, we developed a novel 2-iodothiophene as a wet etching solution to treat the surface of CdTe NC. We found that surface treatment using 2-iodothiophene leads to reduced interface defects and improves carrier mobility simultaneously. The surface properties of CdTe NC thin films after iodide salt treatment are revealed through surface element analysis, space charge limited current (SCLC) studies, and energy level investigations. The CdTe NC solar cells with 2-iodothiophene treatment achieved power conversion efficiency (PCE) of 4.31% coupled with a higher voltage than in controlled devices (with NH4I-treated ones, 3.08% PCE). Full article
(This article belongs to the Special Issue Nano-Based Advanced Thermoelectric Design: 2nd Edition)
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17 pages, 11742 KiB  
Article
The Environmental and Grid Impact of Boda Boda Electrification in Nairobi, Kenya
by Halloran Stratford and Marthinus Johannes Booysen
World Electr. Veh. J. 2025, 16(8), 427; https://doi.org/10.3390/wevj16080427 - 31 Jul 2025
Viewed by 206
Abstract
Boda boda motorbike taxis are a primary mode of transport in Nairobi, Kenya, and a major source of urban air pollution. This study investigates the environmental and electrical grid impacts of electrifying Nairobi’s boda boda fleet. Using real-world tracking data from 118 motorbikes, [...] Read more.
Boda boda motorbike taxis are a primary mode of transport in Nairobi, Kenya, and a major source of urban air pollution. This study investigates the environmental and electrical grid impacts of electrifying Nairobi’s boda boda fleet. Using real-world tracking data from 118 motorbikes, we simulated the effects of a full-scale transition from internal combustion engine (ICE) vehicles to electric motorbikes. We analysed various scenarios, including different battery charging strategies (swapping and home charging), motor efficiencies, battery capacities, charging rates, and the potential for solar power offsetting. The results indicate that electrification could reduce daily CO2 emissions by approximately 85% and eliminate tailpipe particulate matter emissions. However, transitioning the entire country’s fleet would increase the national daily energy demand by up to 6.85 GWh and could introduce peak grid loads as high as 2.40 GW, depending on the charging approach and vehicle efficiency. Battery swapping was found to distribute the grid load more evenly and better complement solar power integration compared to home charging, which concentrates demand in the evening. This research provides a scalable, data-driven framework for policymakers to assess the impacts of transport electrification in similar urban contexts, highlighting the critical trade-offs between environmental benefits and grid infrastructure requirements. Full article
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14 pages, 2075 KiB  
Article
Quantifying Polar Mesospheric Clouds Thermal Impact on Mesopause
by Arseniy Sokolov, Elena Savenkova, Andrey Koval, Nikolai Gavrilov, Karina Kravtsova, Kseniia Didenko and Tatiana Ermakova
Atmosphere 2025, 16(8), 922; https://doi.org/10.3390/atmos16080922 - 30 Jul 2025
Viewed by 196
Abstract
The article is focused on the quantitative assessment of the thermal impact of polar mesospheric clouds (PMCs) on the mesopause caused by the emission of absorbed solar and terrestrial infrared (IR) radiation by cloud particles. For this purpose, a parameterization of mesopause heating [...] Read more.
The article is focused on the quantitative assessment of the thermal impact of polar mesospheric clouds (PMCs) on the mesopause caused by the emission of absorbed solar and terrestrial infrared (IR) radiation by cloud particles. For this purpose, a parameterization of mesopause heating by PMC crystals has been developed, the main feature of which is to incorporate the thermal properties of ice and the interaction of cloud particles with the environment. Parametrization is based on PMCs zero-dimensional (0-D) model and uses temperature, pressure, and water vapor data in the 80–90 km altitude range retrieved from Solar Occultation for Ice Experiment (SOFIE) measurements. The calculations are made for 14 PMC seasons in both hemispheres with the summer solstice as the central date. The obtained results show that PMCs can make a significant contribution to the heat balance of the upper atmosphere, comparable to the heating caused, for example, by the dissipation of atmospheric gravity waves (GWs). The interhemispheric differences in heating are manifested mainly in the altitude structure: in the Southern Hemisphere (SH), the area of maximum heating values is 1–2 km higher than in the Northern Hemisphere (NH), while quantitatively they are of the same order. The most intensive heating is observed at the lower boundary of the minimum temperature layer (below 150 K) and gradually weakens with altitude. The NH heating median value is 5.86 K/day, while in the SH it is 5.24 K/day. The lowest values of heating are located above the maximum of cloud ice concentration in both hemispheres. The calculated heating rates are also examined in the context of the various factors of temperature variation in the observed atmospheric layers. It is shown in particular that the thermal impact of PMC is commensurate with the influence of dissipating gravity waves at heights of the mesosphere and lower thermosphere (MLT), which parameterizations are included in all modern numerical models of atmospheric circulation. Hence, the developed parameterization can be used in global atmospheric circulation models for further study of the peculiarities of the thermodynamic regime of the MLT. Full article
(This article belongs to the Special Issue Observations and Analysis of Upper Atmosphere (2nd Edition))
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10 pages, 1309 KiB  
Proceeding Paper
A Sustainable Approach to Cooking: Design and Evaluation of a Sun-Tracking Concentrated Solar Stove
by Hasan Ali Khan, Malik Hassan Nawaz, Main Omair Gul and Mazhar Javed
Mater. Proc. 2025, 23(1), 4; https://doi.org/10.3390/materproc2025023004 - 29 Jul 2025
Viewed by 132
Abstract
Access to clean cooking remains a major challenge in rural and off-grid areas where traditional fuels are costly, harmful, or scarce. Solar cooking offers a sustainable solution, but many existing systems suffer from fixed positioning and low efficiency. This study presents a low-cost, [...] Read more.
Access to clean cooking remains a major challenge in rural and off-grid areas where traditional fuels are costly, harmful, or scarce. Solar cooking offers a sustainable solution, but many existing systems suffer from fixed positioning and low efficiency. This study presents a low-cost, dual-axis solar tracking parabolic dish cooker designed for such regions, featuring adjustable pot holder height and portability for ease of use. The system uses an Arduino UNO, LDR sensors, and a DC gear motor to automate sun tracking, ensuring optimal alignment throughout the day. A 0.61 m parabolic dish with ≥97% reflective silver-coated mirrors concentrates sunlight to temperatures exceeding 300 °C. Performance tests in April, June, and November showed boiling times as low as 3.37 min in high-irradiance conditions (7.66 kWh/m2/day) and 6.63 min under lower-irradiance conditions (3.86 kWh/m2/day). Compared to fixed or single-axis systems, this design achieved higher thermal efficiency and reliability, even under partially cloudy skies. Built with locally available materials, the system offers an affordable, clean, and effective cooking solution that supports energy access, health, and sustainability in underserved communities. Full article
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13 pages, 2134 KiB  
Article
Optimising Tubular Solar Still Performance with Gamma Aluminium Nanocoatings: Experimental Insights on Yield, Efficiency, and Economic Viability
by Ajay Kumar Kaviti, Niharika Mudavath and Vineet Singh Sikarwar
Processes 2025, 13(8), 2413; https://doi.org/10.3390/pr13082413 - 29 Jul 2025
Viewed by 292
Abstract
This study evaluates the performance of tubular solar stills coated with gamma aluminium nanocoatings at concentrations of 5%, 10%, and 15%, compared to a conventional tubular solar still. This is the first experimental study to apply gamma aluminium nanocoatings on tubular solar stills [...] Read more.
This study evaluates the performance of tubular solar stills coated with gamma aluminium nanocoatings at concentrations of 5%, 10%, and 15%, compared to a conventional tubular solar still. This is the first experimental study to apply gamma aluminium nanocoatings on tubular solar stills (TSS). The stills were tested for three days, from 9:00 a.m. to 5:00 p.m., under consistent conditions with varying water depths of 1 cm, 2 cm, and 3 cm. The results indicated that the 5% nanocoating achieved the highest water yield, producing 2.571 L/m2 with a 1 cm water depth. The 10% coating produced 2.514 L/m2, while the conventional solar still generated 2.286 L/m2. Thermal efficiency was highest on Day 1 for the 5% concentration, reaching 60.9%, followed by 10% concentration at 59.1%, while the 15% concentration showed the lowest efficiency at 33.8%. In terms of cost-effectiveness, the 5% concentration was the most economical, with the lowest cost per litre (CPL) of USD 0.10 and a payback period of 3.03 months. The 10% concentration had a CPL of USD 0.11 and a payback period of 3.33 months, while the 15% concentration had the highest CPL at USD 0.19 and the longest payback period of 5.63 months. Overall, the 5% concentration offered the best balance of water yield, efficiency, and cost-effectiveness. This research highlights γ-Al2O3 as an innovative, cost-effective material for solar distillation, paving the way for sustainable freshwater production. Full article
(This article belongs to the Section Chemical Processes and Systems)
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22 pages, 2795 KiB  
Article
Environmental Stressors Modulating Seasonal and Daily Carbon Dioxide Assimilation and Productivity in Lessonia spicata
by Macarena Troncoso, Zoë L. Fleming, Félix L. Figueroa, Nathalie Korbee, Ronald Durán, Camilo Navarrete, Cecilia Rivera and Paula S. M. Celis-Plá
Plants 2025, 14(15), 2341; https://doi.org/10.3390/plants14152341 - 29 Jul 2025
Viewed by 293
Abstract
Carbon dioxide (CO2) emissions due to human activities are responsible for approximately 80% of the drivers of global warming, resulting in a 1.1 °C increase above pre-industrial temperatures. This study quantified the CO2 assimilation and productivity of the brown macroalgae [...] Read more.
Carbon dioxide (CO2) emissions due to human activities are responsible for approximately 80% of the drivers of global warming, resulting in a 1.1 °C increase above pre-industrial temperatures. This study quantified the CO2 assimilation and productivity of the brown macroalgae Lessonia spicata in the central Pacific coast of Chile, across seasonal and daily cycles, under different environmental stressors, such as temperature and solar irradiance. Measurements were performed using an infra-red gas analysis (IRGA) instrument which had a chamber allowing for precise quantification of CO2 concentrations; additional photophysiological and biochemical responses were also measured. CO2 assimilation, along with the productivity and biosynthesis of proteins and lipids, increased during the spring, coinciding with moderate temperatures (~14 °C) and high photosynthetically active radiation (PAR). Furthermore, the increased production of photoprotective and antioxidant compounds, including phenolic compounds, and carotenoids, along with the enhancement of non-photochemical quenching (NPQ), contribute to the effective photoacclimation strategies of L. spicata. Principal component analysis (PCA) revealed seasonal associations between productivity, reactive oxygen species (ROSs), and biochemical indicators, particularly during the spring and summer. These associations, further supported by Pearson correlation analyses, suggest a high but seasonally constrained photoacclimation capacity. In contrast, the reduced productivity and photoprotection observed in the summer suggest increased physiological vulnerability to heat and light stress. Overall, our findings position L. spicata as a promising nature-based solution for climate change mitigation. Full article
(This article belongs to the Special Issue Marine Macrophytes Responses to Global Change)
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33 pages, 16026 KiB  
Article
Spatiotemporal Analysis of BTEX and PM Using Me-DOAS and GIS in Busan’s Industrial Complexes
by Min-Kyeong Kim, Jaeseok Heo, Joonsig Jung, Dong Keun Lee, Jonghee Jang and Duckshin Park
Toxics 2025, 13(8), 638; https://doi.org/10.3390/toxics13080638 - 29 Jul 2025
Viewed by 232
Abstract
Rapid industrialization and urbanization have progressed in Korea, yet public attention to hazardous pollutants emitted from industrial complexes remains limited. With the increasing coexistence of industrial and residential areas, there is a growing need for real-time monitoring and management plans that account for [...] Read more.
Rapid industrialization and urbanization have progressed in Korea, yet public attention to hazardous pollutants emitted from industrial complexes remains limited. With the increasing coexistence of industrial and residential areas, there is a growing need for real-time monitoring and management plans that account for the rapid dispersion of hazardous air pollutants (HAPs). In this study, we conducted spatiotemporal data collection and analysis for the first time in Korea using real-time measurements obtained through mobile extractive differential optical absorption spectroscopy (Me-DOAS) mounted on a solar occultation flux (SOF) vehicle. The measurements were conducted in the Saha Sinpyeong–Janglim Industrial Complex in Busan, which comprises the Sasang Industrial Complex and the Sinpyeong–Janglim Industrial Complex. BTEX compounds were selected as target volatile organic compounds (VOCs), and real-time measurements of both BTEX and fine particulate matter (PM) were conducted simultaneously. Correlation analysis revealed a strong relationship between PM10 and PM2.5 (r = 0.848–0.894), indicating shared sources. In Sasang, BTEX levels were associated with traffic and localized facilities, while in Saha Sinpyeong–Janglim, the concentrations were more influenced by industrial zoning and wind patterns. Notably, inter-compound correlations such as benzene–m-xylene and p-xylene–toluene suggested possible co-emission sources. This study proposes a GIS-based, three-dimensional air quality management approach that integrates variables such as traffic volume, wind direction, and speed through real-time measurements. The findings are expected to inform effective pollution control strategies and future environmental management plans for industrial complexes. Full article
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13 pages, 1895 KiB  
Article
Class-Dependent Solar Flare Effects on Mars’ Upper Atmosphere: MAVEN NGIMS Observations of X8.2 and M6.0 from September 2017
by Junaid Haleem and Shican Qiu
Universe 2025, 11(8), 245; https://doi.org/10.3390/universe11080245 - 25 Jul 2025
Viewed by 226
Abstract
Transient increments of X-ray radiation and extreme ultraviolet (EUV) during solar flares are strong drivers of thermospheric dynamics on Mars, yet their class-dependent impacts remain poorly measured. This work provides the first direct, side-by-side study of Martian thermospheric reactions to flares X8.2 on [...] Read more.
Transient increments of X-ray radiation and extreme ultraviolet (EUV) during solar flares are strong drivers of thermospheric dynamics on Mars, yet their class-dependent impacts remain poorly measured. This work provides the first direct, side-by-side study of Martian thermospheric reactions to flares X8.2 on 10 September 2017 and M6.0 on 17 September 2017. This study shows nonlinear, class-dependent effects, compositional changes, and recovery processes not recorded in previous investigations. Species-specific responses deviated significantly from irradiance proportionality, even though the soft X-ray flux in the X8.2 flare was 13 times greater. Argon (Ar) concentrations rose 3.28× (compared to 1.13× for M6.0), and radiative cooling led CO2 heating to approach a halt at ΔT = +40 K (X8.2) against +19 K (M6.0) at exobase altitudes (196–259 km). N2 showed the largest class difference, where temperatures rose by +126 K (X8.2) instead of +19 K (M6.0), therefore displaying flare-magnitude dependent thermal sensitivity. The 1.95× increase in O concentrations during X8.2 and the subsequent decrease following M6.0 (−39 K cooling) illustrate the contradiction between photochemical production and radiative loss. The O/CO2 ratio at 225 km dropped 46% during X8.2, revealing compositional gradients boosted by flares. Recovery timeframes varied by class; CO2 quickly re-equilibrated because of effective cooling, whereas inert species (Ar, N2) stabilized within 1–2 orbits after M6.0 but needed >10 orbits of the MAVEN satellite after the X8.2 flare. The observations of the X8.2 flare came from the western limb of the Sun, but the M6.0 flare happened on the far side. The CME shock was the primary driver of Mars’ EUV reaction. These findings provide additional information on atmospheric loss and planetary habitability by indicating that Mars’ thermosphere has a saturation threshold where strong flares induce nonlinear energy partitioning that encourages the departure of lighter species. Full article
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13 pages, 2944 KiB  
Article
Enhancing the Performance of Si/Ga2O3 Heterojunction Solar-Blind Photodetectors for Underwater Applications
by Nuoya Li, Zhixuan Liao, Linying Peng, Difei Xue, Kai Peng and Peiwen Lv
Nanomaterials 2025, 15(14), 1137; https://doi.org/10.3390/nano15141137 - 21 Jul 2025
Viewed by 357
Abstract
Epitaxial growth of β-Ga2O3 nanowires on silicon substrates was realized by the low-pressure chemical vapor deposition (LPCVD) method. The as-grown Si/Ga2O3 heterojunctions were employed in the Underwater DUV detection. It is found that the carrier type as [...] Read more.
Epitaxial growth of β-Ga2O3 nanowires on silicon substrates was realized by the low-pressure chemical vapor deposition (LPCVD) method. The as-grown Si/Ga2O3 heterojunctions were employed in the Underwater DUV detection. It is found that the carrier type as well as the carrier concentration of the silicon substrate significantly affect the performance of the Si/Ga2O3 heterojunction. The p-Si/β-Ga2O3 (2.68 × 1015 cm−3) devices exhibit a responsivity of up to 205.1 mA/W, which is twice the performance of the devices on the n-type substrate (responsivity of 93.69 mA/W). Moreover, the devices’ performance is enhanced with the increase in the carrier concentration of the p-type silicon substrates; the corresponding device on the high carrier concentration substrate (6.48 × 1017 cm−3) achieves a superior responsivity of 845.3 mA/W. The performance enhancement is mainly attributed to the built-in electric field at the p-Si/n-Ga2O3 heterojunction and the reduction in the Schottky barrier under high carrier concentration. These findings would provide a strategy for optimizing carrier transport and interface engineering in solar-blind UV photodetectors, advancing the practical use of high-performance solar-blind photodetectors for underwater application. Full article
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9 pages, 4992 KiB  
Communication
Corrosion Behavior of 347H Stainless Steel in NaCl-KCl-MgCl2 Molten Salt: Vapor, Liquid, and Interface Comparison
by Zhiwen Liu, Huigai Li, Yang Wang, Yanjie Peng, Luyan Sun and Jianping Liang
Materials 2025, 18(14), 3412; https://doi.org/10.3390/ma18143412 - 21 Jul 2025
Viewed by 241
Abstract
The suitability of 347H stainless steel (SS347H) for chloride salt environments is critical in selecting materials for next-generation concentrated solar power (CSP) systems. This study investigated the corrosion behavior of SS347H in a ton-scale purification system with continuously flowing chloride salt under three [...] Read more.
The suitability of 347H stainless steel (SS347H) for chloride salt environments is critical in selecting materials for next-generation concentrated solar power (CSP) systems. This study investigated the corrosion behavior of SS347H in a ton-scale purification system with continuously flowing chloride salt under three conditions: exposure to NaCl-KCl-MgCl2 molten salt vapor, immersion in molten salt, and at the molten salt surface interface. Results revealed that corrosion was most severe in the molten salt vapor, where HCl steam facilitated Cl reactions with Fe and Cr in the metal, causing dissolution and forming deep corrosion pits. At the interface, liquid Mg triggered displacement reactions with Fe2+/Cr2+ ions in the salt, depositing Fe and Cr onto the surface, which reduced corrosion intensity. Within the molten salt, Mg’s purification effect minimized impurity-induced corrosion, resulting in the least damage. In all cases, the primary corrosion mechanism involves the dissolution of Fe and Cr, with the formation of minor MgO. These insights provide valuable guidance for applying 347H stainless steel in chloride salt environments. Full article
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21 pages, 5122 KiB  
Article
Comparative Life Cycle Assessment of Solar Thermal, Solar PV, and Biogas Energy Systems: Insights from Case Studies
by Somil Thakur, Deepak Singh, Umair Najeeb Mughal, Vishal Kumar and Rajnish Kaur Calay
Appl. Sci. 2025, 15(14), 8082; https://doi.org/10.3390/app15148082 - 21 Jul 2025
Viewed by 881
Abstract
The growing imperative to mitigate climate change and accelerate the shift toward energy sustainability has called for a critical evaluation of heat and electricity generation methods. This article presents a comparative life cycle assessment (LCA) of solar and biogas energy systems on a [...] Read more.
The growing imperative to mitigate climate change and accelerate the shift toward energy sustainability has called for a critical evaluation of heat and electricity generation methods. This article presents a comparative life cycle assessment (LCA) of solar and biogas energy systems on a common basis of 1 kWh of useful energy using SimaPro, the ReCiPe 2016 methodology (both midpoint and endpoint indicators), and cumulative energy demand (CED) analysis. This study is the first to evaluate co-located solar PV, solar thermal compound parabolic concentrator (CPC) and biogas combined heat and power (CHP) systems with in situ data collected under identical climatic and operational conditions. The project costs yield levelized costs of electricity (LCOE) of INR 2.4/kWh for PV, 3.3/kWh for the solar thermal dish and 4.1/kWh for biogas. However, the collaborated findings indicate that neither solar-based systems nor biogas technology uniformly outperform the others; rather, their effectiveness hinges on contextual factors, including resource availability and local policy incentives. These insights will prove critical for policymakers, industry stakeholders, and local communities seeking to develop effective, context-sensitive strategies for sustainable energy deployment, emissions reduction, and robust resource management. Full article
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