Search Results (11,897)

In the present study, the potential applications of Cu thin films and Ag/Cu bilayer thin films obtained by the pulsed laser deposition (PLD) technique are investigated in terms of the physicochemical effects resulting from their interaction with an aqueous solution containing Reactive Blue 21 (RB21) dye and sodium bicarbonate (NaHCO₃). The thin-film deposition process was carried out using a Q-switched Nd:YAG laser system operating at a wavelength of λ = 532 nm, with a pulse duration of τ = 10 ns, a repetition rate of ν = 10 Hz, a pulse energy of E = 180 mJ, a laser spot diameter of d = 336 μm, and an angle of incidence of α = 45°. Two types of thin films were prepared: a Cu thin film and an Ag/Cu bilayer thin film. The thermal effects induced by the interaction of the laser beam with the target materials were investigated by numerical simulations performed in COMSOL, allowing the evaluation of melt-phase formation for each material separately and providing a better understanding of the morphology and topography of the deposited thin films. The simulation results were validated through scanning electron microscopy (SEM) observations and surface roughness analyses. The two thin films were subsequently treated with an aqueous solution containing 10 g/L RB21 dye and 10 g/L NaHCO₃. Physicochemical analyses performed after treatment, including scanning electron microscopy (SEM), optical microscopy (OM), profilometry, Fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDS), X-ray Photoelectron Spectroscopy (XPS) and UV–Vis spectroscopy, revealed significant degradation of the RB21 dye accompanied by corrosion of the thin films, with the corrosion process being more pronounced in the case of the Cu thin film. The obtained results indicate that the method analyzed in this study may represent an alternative approach for the decomposition of recalcitrant organic dyes using thin Cu films, without relying on conventional photocatalytic processes. Equally important are the potential applications of the RB21/NaHCO₃ solution as an etching and patterning medium for thin Cu layers, while the Ag overlayer may provide a protective effect during such processes. These findings may contribute to the development of novel fabrication techniques for optoelectronic components, including solar cells, photovoltaic windows, and other industrial and laboratory applications. Full article

Small modular reactors (SMRs) offer firm low-carbon heat and power, and data centers concentrate large, continuous electrical and cooling loads. Transparent tools for screening their thermal integration are scarce. To the authors’ knowledge, this paper develops the first steady-state thermodynamic framework that couples SMR steam extraction, solar thermal input, and recovered data-center liquid-cooling heat through a single mixing-tank thermal bus serving both an absorption chiller and an organic Rankine cycle (ORC). The framework’s novelty is in its focus on the structural level rather than the component level. Two consistency requirements are built into its equations. First, the data-center control volume closes exactly, so that recovered heat reduces the residual cooling demand and heat removal equals IT dissipation. Second, delivered cooling is credited identically in every configuration compared, so that apparent gains cannot arise from asymmetric accounting. The framework identifies the governing mechanism of the architecture: a small 120 °C extraction stream (1.01% of core thermal power at the activation bound) unlocks the larger 70 °C recovered stream, which cannot drive the chiller alone. At the margin-constrained design point (2.93% extraction), direct liquid recovery removes 20.9 MW_th, absorption cooling serves the remaining 16.2 MW_th, and net electricity is 5.8 MW_e above the all-electric reference. An itemized estimate places the integration-specific parasitic loads at 0.6–1.5 MW_e (central value 1.0 MW_e), which reduces the increment over the liquid-cooled non-integrated reference from $+0.5$ MW_e (gross) to approximately $-0.5$ MW_e (net). A 20,000-sample Monte Carlo analysis across seven uncertain parameters shows the net-of-parasitics gain over the all-electric reference is positive with 92% probability (median $+4.1$ MW_e), while the increment over the non-integrated reference is positive with only 29% probability. A compact exergy inventory attributes 7.1 MW of destruction to the recovery train (process heat exchanger 2.0, mixing 1.2, ORC 2.0, chiller 2.0). The architecture’s robust value therefore lies in thermally driven cooling and the productive use of recovered heat, not in net energy. The framework is a screening tool rather than a validated plant model; a companion study populates it with published plant, climate, and equipment data. Full article

Reliable rooftop photovoltaic planning requires design-stage energy predictions to be verified against actual system performance. The novelty of this study is the integration of a multi-year assessment of agreement with PV*SOL design estimates with an independent assessment of normalized productivity, interannual variability, seasonality, and meteorological effects for several rooftop systems operating under the same regional conditions. PV*SOL, a commercial photovoltaic simulation software used to estimate system energy production during the design stage, was evaluated using three years (2023–2025) of monitored data from three rooftop photovoltaic (PV) systems (17.60–75.40 kWp) in Rzeszów, south-eastern Poland. The analysis comprised 108 installation-month observations and included final yield, capacity factor, annual prediction errors, seasonal variability, Pearson correlations, and hierarchical regression. Mean annual final yield ranged from 907.4 to 966.2 kWh/kWp, while annual deviations from PV*SOL design estimates ranged from −0.80% to +7.41%. Monthly final yield was strongly associated with solar irradiation, and the final hierarchical regression model explained 96.4% of its variability. The results indicate that PV*SOL provides a useful annual design reference, but operational monitoring and local benchmark data remain essential for reliable performance assessment. The study supports United Nations Sustainable Development Goal 7 (Affordable and Clean Energy) by improving the evidence base for rooftop photovoltaic planning and monitoring. Full article

As renewable energy penetration increases, renewable energy curtailment has become a critical challenge in power systems with high shares of solar and wind generation. This study develops a mixed-integer linear programming (MILP) model for the day-ahead scheduling of battery energy storage systems (ESS) to minimize renewable energy curtailment on Jeju Island, South Korea. Simulation results based on 2024 operational data show that ESS effectively reduces curtailment by shifting surplus renewable energy over time; however, its benefits diminish as storage capacity increases because additional charging is no longer possible once the ESS reaches its capacity limit. Under a scenario in which renewable energy capacity doubles relative to 2024 levels, large-scale ESS deployment alone could not eliminate seasonal curtailment. In contrast, integrating ESS with a 15% increase in electricity demand substantially reduced curtailment, highlighting the critical role of demand growth in absorbing surplus renewable generation. These findings demonstrate that battery storage alone is insufficient for high-renewable island power systems. Instead, an integrated flexibility strategy combining ESS with demand-side management, sector coupling (e.g., Power-to-Gas), and enhanced transmission interconnections is required to maximize renewable energy utilization while maintaining system reliability. Full article

This work offers a reliability framework for a five-subsystem hybrid series-parallel system representing smart factory monitoring infrastructure under heat and vibration stressors. A central programmable logic controller (1-out-of-1), pressure and temperature sensors (2-out-of-5), wireless communication units (2-out-of-4), solar power modules (3-out-of-6), and a cold standby database server (1-out-of-2) are connected in series. Unit failures are modeled using exponential distributions with component-specific failure rates and two environmental failure rates for thermal stress (${\alpha }_6$) and vibration stress (${\alpha }_7$) which go beyond the single-parameter models used in prior research. Repair of degraded states is governed by general distributions. The Gumbel–Hougaard copula family deals with total failure states, permitting positive repair time dependence due to common maintenance resources and environmental recovery. The state probabilities are obtained in closed form by using Laplace transforms and the supplementary variable method. Those state probabilities are used to find system availability, reliability, $MTTF$, sensitivity, indices and profit for three cases: copula-based repair, general distribution repair and a reduction technique with parameter $\rho$. Numerical analysis reveals steady state availability of 96.80%when using copula repair, and 99.35% when using the reduction technique ($\rho$ = 0.2). Sensitivity analysis reveals that the solar power module subsystem is the main cause of $MTTF$ degradation, however cost analysis reveals that proactive quality enhancement is more profitable than reactive repair options at all maintenance expenditure levels. Full article

Background: The optical losses in the form of reflections, parasitic absorption, and scattering limit photovoltaic efficiency. This review examines plasma-assisted surface engineering as an effective tool for improving light management in solar cells. Plasma-based methods, including etching, oxidation, deposition, and texturing, enable precise control of surface morphology and chemistry, lowering reflectance, enhancing light trapping, and passivating defects. Methods: In contrast to wet-chemical or high-temperature processes, plasma processes are dry, low-temperature, scalable, and can be used with silicon, perovskite, thin-film, and organic solar cells, as well as tandem structures. The fundamentals of optical losses are described, along with the principles of radio-frequency (RF), inductively coupled plasma (ICP), microwave, and atmospheric plasma systems and their distinctive advantages for controlling ion and reactive-species generation. Key applications reviewed include black-silicon texturing by ICP reactive-ion etching (ICP-RIE), anti-reflective/passivation coatings by plasma-enhanced chemical vapor deposition (PECVD), and interface activation by atmospheric plasma. Results: Among performance improvements are a reflectance of less than 2%, a photocurrent increase of 10–20%, and longer carrier lifetime. Conclusions: The advantages of plasma compared to lithography and sol–gel processes are in the precision and affordability of the method. The difficulties include damage caused by the processing, uniformity over extensive areas, and environmental stress resistance. Future directions rely on low-temperature plasmas for flexible PV, machine-learning-guided process optimization, and hybrid plasma–laser systems. This synthesis of otherwise fragmented studies is intended to support the implementation of plasma-based methods in next-generation, high-efficiency, and sustainable solar production. Full article

Inverter-interfaced distributed generation (DG) can provide voltage support in unbalanced distribution feeders; however, sequential, phase-selective siting and sizing under local interconnection constraints have received limited attention. This study proposes a constructive Volt/VAR planning method that allocates DG according to the apparent demand and voltage-deficient phases at each candidate bus. A descending reactive power feasibility test rejects solutions that cause non-convergence, overvoltage, or deterioration of the minimum system voltage. The method was implemented through automated unbalanced three-phase power-flow simulations and tested on the IEEE 13-node feeder and the real 3849-bus CHIRIPA medium-voltage network in Honduras, using active power allocation factors of 0.7 and 0.9. The selected configurations were evaluated over 24 h profiles for representative sunny and rainy days, annualized, and assessed economically over a 25-year horizon. Annual energy losses decreased by 25.8% and 26.4% in the IEEE feeder, although local capacity constraints prevented all phase voltages from reaching the 0.95–1.05 p.u. range. In CHIRIPA, all medium-voltage bus-phase voltages satisfied this range at maximum demand, although this improvement persisted only during solar hours; annual losses fell by 15.1% and 18.7%. The economic feasibility threshold in CHIRIPA depended primarily on installed capacity (approximately 6.5–6.6 MW), rather than unit count. These results provide a reproducible framework for prioritizing phase-specific DG investments under technical and economic constraints. Full article

Carbon dioxide (CO₂) enrichment is an important means of increasing crop productivity in protected cultivation. However, local canopy CO₂ concentration in Chinese solar greenhouses is jointly affected by gas release, pipeline transport, and ventilation disturbances, making fixed-parameter proportional–integral–derivative (PID) control unable to simultaneously achieve rapid tracking, low overshoot, and fast disturbance recovery. This study developed a CO₂ enrichment system comprising controlled thermal decomposition of ammonium bicarbonate, condensation and water scrubbing, near-canopy delivery, and programmable logic controller (PLC)-based closed-loop control, and proposed a dynamic-target fuzzy PID (DT-FPID) strategy. Step-response tests were used to establish a first-order-plus-dead-time model linking heater duty cycle to local canopy CO₂ concentration, followed by fixed-target tracking, rule-based dynamic-target execution, and short-term ventilation-disturbance recovery tests in a local validation zone of a Chinese solar greenhouse. Relative to fixed-parameter PID, DT-FPID showed approximately 68–79% lower maximum overshoot and approximately 35–70% shorter ±20 ppm precision settling time (T₂₀) in simulation. At 600 ppm, the ±5% settling time was approximately 71% shorter, whereas at 800 and 1000 ppm it was broadly comparable to PID. In the greenhouse experiments, each controller–target combination included three independent runs. Based on descriptive comparisons of group means, DT-FPID showed approximately 47–49% lower mean maximum overshoot, approximately 36–40% shorter mean settling time, and approximately 77–80% shorter mean ventilation-disturbance recovery time; its mean maximum overshoot and settling time were also lower than those of conventional fuzzy PID. All three dynamic-target field runs completed the prescribed switches among the 600, 800, and 1000 ppm target levels. These results support control performance only under the short-term local validation conditions of this study; they are not used to determine physiologically or economically optimal CO₂ concentrations or to extrapolate whole-greenhouse uniformity or long-term production effects. Full article

Building facades and construction materials are continuously exposed to airborne particulate matter, organic pollutants, and microbial colonization, which cause progressive soiling, aesthetic degradation, and structural deterioration while imposing high maintenance and energy burdens. Photocatalytic titanium dioxide (TiO₂) has emerged as the most widely studied material for imparting self-cleaning functionality to building surfaces, owing to its ability to mineralize adsorbed contaminants under solar irradiation and to modulate surface wettability. This narrative review provides a structured account of TiO₂-based self-cleaning coatings for building materials, organized around three complementary themes: surface mechanisms, performance metrics, and outdoor durability. We first rationalize the two intertwined self-cleaning mechanisms—photocatalytic oxidative degradation and photoinduced superhydrophilicity—and their combination with physically repellent (superhydrophobic/superamphiphobic) wetting states. We then survey the principal coating-design strategies, including morphology and facet engineering, SiO₂-TiO₂ composites, metal/non-metal doping and heterojunction construction for visible-light activation, and dual-functional photocatalytic–superhydrophobic systems, and their integration into cementitious substrates, natural stone and cultural heritage, and transparent glass/photovoltaic surfaces. The quantitative metrics used to benchmark self-cleaning performance—water contact angle, dye photodegradation, NO_x and VOC abatement, and antimicrobial activity—are critically discussed together with the limitations of standardized laboratory tests. Finally, we analyze the weathering-induced deactivation pathways (photocatalyst leaching, surface contamination by soluble salts, and UV aging of organic matrices) and the emerging strategies for durable coatings, including inorganic binders, light-driven hydration, and defect- and heterojunction-engineered photocatalysts. The review concludes with an outlook on the open challenges that must be addressed to translate these coatings from laboratory demonstrations to long-lived, large-scale building applications. Full article

The increasing integration of distributed energy resources and flexible loads has transformed university campuses into complex energy systems that require coordinated operational strategies capable of managing renewable uncertainty while maintaining economic and environmental performance. This paper proposes a two-stage stochastic mixed-integer linear programming (MILP) framework for the optimal day-ahead energy management of a smart university campus. The proposed model jointly coordinates photovoltaic generation, battery energy storage systems, electric vehicle charging, HVAC operation, and demand response under uncertainties associated with solar generation, electricity demand, energy prices, and ambient temperature. Unlike previous campus energy management approaches, the proposed framework explicitly distinguishes first-stage scheduling decisions from second-stage recourse actions, enabling adaptive operation while preserving decision consistency across uncertainty scenarios. A realistic case study based on the operational characteristics of the Universidad Politécnica Salesiana campus in Ecuador is used to evaluate the proposed methodology. The results demonstrate that the coordinated stochastic scheduling strategy reduces daily operating costs by 36.37%, decreases CO₂ emissions by 42.81%, and lowers peak grid demand by 37.99% compared with conventional operation. In addition, photovoltaic self-consumption reaches 91.7%, while renewable energy utilization increases to 93.4% without compromising occupant thermal comfort. The proposed framework provides a scalable pathway toward low-carbon, resilient, and energy-efficient smart campus operation. Full article

Drawing on ERA5 reanalysis data for 2005–2025, this study examines long-term environmental change across China’s eight major deserts and on this basis develops a data-informed framework for integrating geoscientific evidence into geographical fieldwork education. Temperature change, surface radiation and vertical soil moisture profiles are used to construct inquiry tasks on regional warming, land–atmosphere interactions and dryland hydrology. A four-dimensional resource assessment integrating solar resource abundance, thermal stability, soil moisture support and wind exposure stability is then applied using multi-criteria decision analysis (MCDA) to compare relative resource characteristics and ecological constraints across desert regions. The contrasting resource profiles of the Taklimakan, Tengger, and Kubuqi Deserts provide the basis for a scenario-based decision-making activity incorporating equal-weight, energy-priority, and ecology-priority perspectives on renewable energy development and ecological protection. Rather than treating deserts as static landscapes, the proposed framework positions them as dynamic coupled human–environment systems and is designed to engage students in interpreting long-term datasets, comparing regional processes and evaluating sustainability trade-offs. The study illustrates how environmental datasets can be organised into fieldwork questions, analytical tasks and decision scenarios, offering an adaptable framework in which quantitative reasoning, systems thinking and evidence-based sustainability learning are specified as intended educational outcomes in higher geographical education. Full article

In the context of global energy transition and climate change, exogenous energy shocks (such as energy price volatility, renewable energy uncertainty, and increasing power demand) pose growing challenges to power system carbon neutrality. However, existing studies mainly focus on optimizing emission-reduction pathways while neglecting system resilience under energy shocks. This study applies a coupled LEAP-NEMO model for Guangdong Province, integrating demand growth, generation evolution, dispatch optimization, system costs, and carbon constraints. Five scenarios (BAS, COM, COM_ES1, COM_ES2, and COM_ES3) are established to assess the impacts of exogenous energy shocks on carbon-neutral transition pathways. The results show that under COM scenario, Guangdong’s power system’s carbon emissions will peak by 2030 and reach net-zero by 2055. Different energy shocks produce substantially different effects on the carbon-neutral transition. Fossil fuel price shocks (COM_ES1) have limited impacts, with cumulative emissions changing by only 2.1% relative to COM. Renewable energy volatility (COM_ES2) reduces wind and solar generation and raises cumulative emissions by 73.7%, preventing carbon neutrality by 2060. Demand growth (COM_ES3) poses the most severe challenge, with cumulative emissions reaching 2.04 times those of the COM scenario. Resilience analysis further shows that renewable energy volatility causes the largest deterioration in reserve margin performance, while demand growth has the strongest effects on emissions and cost performance. These results identify renewable generation uncertainty and electricity demand growth as the key risks to a smooth carbon-neutral transition, highlighting the need for coordinated deployment of energy storage, nuclear power, flexible resources, and demand-side management. Full article

This paper proposes a parametric modeling and multi-objective optimization method based on optomechanical coupling analysis to address the design optimization of large-aperture primary mirrors in space-based solar extreme ultraviolet (EUV) imaging instruments. By establishing a parametric model of the primary mirror and combining topology optimization with dimensional optimization, the influence of key parameters—including mirror thickness, rib width, and lightweight hole dimensions—on the mirror surface shape accuracy (RMS) and structural fundamental frequency is systematically analyzed. The study employs finite element simulation and optomechanical coupling data processing algorithms to extract the rigid-body displacement and surface shape error of the primary mirror under gravitational loading and identifies high-impact parameters through sensitivity analysis. After optimization, the RMS values of the mirror’s surface shape in all three directions under a 1 g gravitational load are all better than 4.5 nm, meeting the requirements for spaceborne payloads. Experimental validation shows that the surface shape RMS of the assembled primary mirror is only 0.022λ (with λ = 632.8 nm), and the system wavefront error is less than 0.08λ, significantly surpassing the design specification requirement of 0.1λ. Full article

Driven by China’s carbon peaking and carbon neutrality goals and the low-carbon transition of offshore oil and gas operations, the integration of offshore oil and gas with wind, solar, marine, and hydrogen energy is emerging as an important pathway for balancing energy security, emission reduction, and operational efficiency. Focusing on system boundaries and positions along the energy chain, this paper classifies offshore oil and gas–renewable energy integration into four representative pathways: shore power electrification, platform microgrid integration, hydrogen production and export, and energy islands or regional hubs. This study provides a structured narrative review of the key technologies, major constraints, and feasible implementation approaches associated with these pathways from the perspectives of offshore microgrid architecture, energy storage and backup, energy management, and offshore engineering installation, operation, and maintenance. The results indicate that the coordinated use of multiple energy sources and microgrid-based integration is particularly relevant to single-platform and small-cluster scenarios requiring local power balancing and progressive electrification. However, wider deployment remains constrained by resource intermittency, the safety and lifetime of energy storage systems, cross-system coordinated control, offshore engineering reliability, and the lack of a comprehensive standards system. This study provides a reference for offshore platform electrification retrofits in China, the comparison and selection of integration schemes, and the planning of demonstration projects. Full article

Cement production generates approximately 7% of global CO₂ emissions; Jordan’s kilns run on petroleum coke, coal, and olive residue with no demonstrated solar thermal integration for pre-heating. This paper addresses that gap and presents the first plant-data-backed techno-economic and environmental assessment of a hybrid dual-stage concentrating solar thermal system integrated into the pre-heater tower of a cement plant in Ma’an, Jordan (30.2° N, direct normal irradiance (DNI) = 2749 kWh/m²/yr). The study objectives are to (i) characterize Stage 5 and Stage 6 thermal loads from real plant operating data; (ii) size and simulate a 6000 m² parabolic trough collector (PTC) field with molten-salt thermal energy storage (TES) targeting Stage 5 (380 °C, 3200 kW) and an 8000 m² Linear Fresnel Reflector (LFR) field with rock/PCM TES targeting Stage 6 (300 °C, 2200 kW); (iii) quantify the combined solar fraction, fuel savings, and CO₂ avoidance; (iv) conduct a Jordan-specific cost analysis benchmarked against NREL 2015 solar heat for industrial process (SHIP) data under three CAPEX scenarios; and (v) evaluate net present value (NPV) at two discount rates with and without carbon credits. The PTC field achieves a Stage 5 solar fraction of 35.5%, and the LFR field achieves 50.0% at Stage 6, yielding a combined annual solar fraction of 41.4% and displacing 59,384 GJ/yr (4163 t CO₂/yr). Under Jordan base-case CAPEX of $3.89 M, 6% concessional finance, and a $50/t CO₂ carbon credit, NPV reaches +$1.11 M with a breakeven carbon credit of $29/t CO₂. These results confirm commercial viability under accessible green finance and carbon pricing, providing a replicable model for cement kiln pre-heater decarbonization in high-DNI Middle East and North Africa (MENA) countries. Full article