Search Results (1,880)

We report a low-temperature plasma–liquid synthesis of crystalline β-Ga₂O₃ nanoparticles directly from aqueous solution. Pulsed discharge plasma bubbles generate reactive species that drive in situ dehydration and crystallization, bypassing the high-temperature calcination required by conventional methods. By varying the carrier gas, we tune morphology from uniform nanorice structures (He, Ar, and N₂) to amorphous microspheres (O₂ and air), revealing how plasma composition governs interfacial hydroxyl radical chemistry and growth kinetics. This approach demonstrates that localized plasma heating and reactive-species flux can achieve phase-selective oxide crystallization under ambient conditions, establishing plasma bubble reactors as a broadly applicable, low-temperature route for direct aqueous synthesis of crystalline wide-bandgap oxides that bridge solution chemistry and plasma nanomaterials design. Full article

In this work, plasmonic photoconductive antenna (PCA) structures with different grating-width and gap configurations were numerically investigated to evaluate their influence on transient-current generation and terahertz (THz) emission performance. Two geometrical scaling strategies were considered: a fixed-gap configuration with a constant 100 nm photoconductive gap and a proportional-gap configuration in which the gap size was equal to the grating width. Three-dimensional finite element method (FEM) simulations were performed to analyze transient carrier dynamics, THz pulse electric-field behavior, and frequency-domain spectral response under 800 nm optical excitation. The results demonstrate that reducing the inter-grating gap enhances plasmonic near-field confinement and carrier localization near the metal–semiconductor interface, leading to stronger transient-current responses and enhanced THz characteristics. Spatial field and carrier-distribution analyses further confirmed improved electric-field localization and carrier confinement for the fixed-gap structures. In addition, voltage-dependent investigations showed that increasing the applied bias voltage strengthens carrier acceleration and enhances the simulated THz response within the investigated operating range. The results further demonstrate that the observed enhancement is governed not only by grating periodicity but also by the grating-width/gap-size ratio, highlighting the importance of geometrical fill-factor optimization. Polarization-dependent simulations confirmed the plasmonic origin of the enhanced transient-current generation and THz emission. These findings demonstrate that optimal THz performance arises from a balanced interplay between plasmonic field localization, optical absorption, and carrier-transport dynamics, providing design guidelines for the optimization of plasmonic THz PCAs. Full article

Ammonia is a promising zero-carbon energy carrier for maritime decarbonisation, but its deployment is limited by safety risks that are not adequately addressed by conventional marine fuel safety frameworks. This study critically reviews safety assessment, risk management and control strategies for ammonia storage and handling in maritime applications using a PRISMA-informed literature synthesis. Evidence is analysed across hazard characterisation, storage configurations, transfer operations, risk assessment methods, mitigation barriers and regulatory frameworks. The review shows that ammonia safety is governed by coupled release–exposure–barrier interactions shaped by storage condition, tank configuration, pressure–temperature behaviour, material compatibility, transfer mode, ventilation, ship geometry and human intervention. Existing methods, including HAZID, HAZOP, risk matrices and QRA, support hazard screening and prioritisation, but remain limited in representing flashing two-phase releases, dense gas dispersion, confined-space accumulation, exposure duration, ventilation effectiveness and safeguard timing under maritime conditions. CFD, FTA, Bayesian approaches and Monte Carlo analysis offer higher analytical resolution, but their reliability is constrained by limited validation data, uncertain leak-frequency inputs and simplified assumptions for human exposure and emergency response. Effective risk control therefore requires a toxicity-centred barrier strategy linking containment integrity, ammonia-compatible materials, gas and process monitoring, emergency shutdown, ventilation, water-based mitigation, PPE, competency-based training and emergency planning. Current regulatory and classification guidance provides an essential foundation but remains fragmented and insufficiently aligned with ammonia-specific requirements for exposure modelling, safety-zone definition and approval pathways. This review contributes a maritime-specific synthesis of ammonia storage and handling safety by connecting hazard behaviour, storage design, transfer operations, risk assessment limitations, control-barrier logic and regulatory approval needs. The findings highlight the need for validated source-term models, full-scale release and dispersion data, exposure-based safety criteria and harmonised regulatory pathways to support the safe and scalable use of ammonia in maritime decarbonisation. Full article

Natural gas transportation and distribution networks are becoming increasingly heterogeneous due to the injection of biomethane, regasified LNG, and hydrogen-enriched natural gas, requiring distributed and continuous gas-quality monitoring. This work presents an industrial Raman-based instrument for in-line measurement of natural gas and hydrogen-enriched natural gas composition and related thermodynamic properties. The system employs a 450 nm broadband laser diode, a high-throughput custom spectrometer, and a pressure-rated gas cell integrated in an ATEX-certified enclosure. Gas composition is retrieved through calibration spectra and non-linear least-squares fitting, while higher heating value is calculated according to ISO 6976. The instrument was validated over pressures from 1.5 to 17 bara and temperatures from −20 °C to 55 °C using certified representative gas mixtures. The system achieved compliance with OIML R 140 Class A requirements, with HHV errors below ±0.5% and repeatability within 0.1%, while operating without carrier gases or sample manipulation. Long-term field operations in pressure-reduction stations confirmed stable performance over twelve months. The results demonstrate that Raman spectroscopy can provide a robust, low-maintenance solution for continuous natural-gas-quality monitoring and controlled hydrogen-blending applications. Full article

Hydrogen (H₂), produced from syngas and the Water–Gas Shift reaction, plays a vital role as both an energy carrier and an essential industrial feedstock. This preliminary study examines the effect of incorporating ionic liquids into PLA membranes for the separation of hydrogen (H₂) from carbon dioxide (CO₂), aiming to provide a more energy-efficient alternative to the conventional Pressure Swing Adsorption process. Specifically, neat PLA and composite membranes containing cholinium-based ionic liquids at concentrations of 3% and 10% were fabricated. Their thermal properties and microstructural characteristics were systematically analyzed, alongside their gas separation performance. The most promising membrane was further evaluated under humid conditions to assess the impact of water presence. The PLA membrane incorporating 3% cholinium glycinate ionic liquid demonstrated the best performance, achieving a hydrogen permeability of 111 Barrer and an H₂/CO₂ selectivity of 8.2, surpassing the Robeson Upper Bound reported in 2008. However, the presence of water led to a decline in separation performance, indicating that effective water removal is necessary prior to membrane application in hydrogen purification. Full article

Green hydrogen is increasingly discussed as an energy carrier that can link electricity, gas, heat, and transport sectors. However, many existing reviews address this topic from separate viewpoints, such as hydrogen production technologies, Artificial Intelligence (AI) applications, or system integration, with less attention to how policy and market conditions affect deployment. This review brings these related aspects together in one structured discussion. The paper first reviews the hydrogen supply chain, including production, storage, transport, and utilization. It then discusses an integrated multi-energy architecture in which hydrogen interacts with electricity, natural gas, heat, and cooling networks. Policy instruments in five major economies, including the European Union, the United States, China, Japan, and India, are compared. The review also summarizes the main barriers to large-scale deployment, including high production costs, limited infrastructure, technological challenges, regulatory uncertainty, and supply-chain constraints. In addition, the current market structure and selected large-scale hydrogen projects planned in the United States are reviewed. The paper also examines the role of artificial intelligence in green hydrogen systems. AI applications are grouped into four main stages of the hydrogen value chain: forecasting renewable energy generation, improving electrolyzer design and operation, optimizing storage and distribution, and supporting system-level techno-economic assessment. Recent Machine Learning (ML) studies are compared based on their methods and their contributions to operation and planning. Overall, this review highlights the role of AI in enabling green hydrogen integration within multi-energy systems. Full article

Background/Objectives: Arthrochalasia Ehlers–Danlos syndrome (aEDS) is a rare connective tissue disorder characterized by severe joint hypermobility, congenital hip dislocation, skin hyperextensibility, and muscle hypotonia. It is typically caused by heterozygous splice-site variants in COL1A1 or COL1A2, leading to exon 6 skipping. Autosomal recessive forms are extremely rare and have been reported predominantly in families from Saudi Arabia carrying the homozygous COL1A1 missense variant c.2050G>A, p.(Glu684Lys), with clinical presentations ranging from severe to mild. Methods: Clinical and molecular genetic evaluation of the patient was performed. Whole-exome sequencing was carried out, followed by confirmatory Sanger sequencing in the proband and both parents. Results: A 10-month-old boy presented with severe congenital hypotonia, bilateral hip dislocation, generalized joint hypermobility, skin hyperextensibility and craniofacial dysmorphism. A homozygous likely pathogenic variant NM_000088.4:c.2050G>A, p.(Glu684Lys) was identified in exon 31 of COL1A1; both healthy parents were confirmed to be heterozygous carriers of this variant. To our knowledge this is the first reported case in the Russian population and one of the few cases described worldwide of an autosomal recessive arthrochalasia-like EDS phenotype. Conclusions: This case further refines the phenotypic characterization associated with the recurrent homozygous COL1A1 p.(Glu684Lys) variant, demonstrating an arthrochalasia-like EDS phenotype of intermediate severity between the severe neonatal form with respiratory distress and recurrent fractures and the classical EDS. It further highlights the importance of considering collagenopathies in the differential diagnosis of congenital hypotonia, particularly in cases initially suggestive of neuromuscular disorders. Full article

Addressing the critical limitation of high operating temperatures plaguing conventional resistive gas sensors, this work reports the synthesis of Zn-doped SnS gas-sensing materials with doping concentrations of 0%, 2%, and 4% via a one-step hydrothermal route—an approach that enables precise regulation of dopant distribution and material microstructure. Systematic gas-sensing tests demonstrate that all as-prepared sensors exhibit remarkable responsiveness to methanol at a reduced optimal operating temperature of 240 °C, with the response values increasing significantly with Zn doping content: 22.1% for pristine SnS, 48.9% for 2% Zn-doped SnS, and 65.2% for 4% Zn-doped SnS when exposed to 50 ppm methanol. Beyond enhanced response, the Zn-doped SnS sensors maintain excellent methanol selectivity against interfering gases (e.g., ethanol, formaldehyde, acetone) and achieve a low detection limit of 5 ppm, which meets the practical requirements for trace methanol monitoring. The superior performance of 4% Zn-doped SnS—exhibiting a 195% response enhancement compared to pristine SnS—originates from the synergistic effects of Zn-induced defect engineering and improved charge carrier mobility, as supported by structural and electrical characterizations. This study not only provides a facile strategy for developing low-temperature-operating methanol sensors but also highlights the potential of Zn-doped SnS as a promising candidate for high-performance gas-sensing applications in environmental monitoring, industrial safety, and biomedical detection. Full article

Low-temperature photoluminescence (PL) has been studied under hydrostatic pressure and varying excitation powers in three samples of single In_0.17Ga_0.83N quantum wells with different widths: 2.6 nm, 5.2 nm, and 10.4 nm. Transitions involving ground states were strong in the 2.6 nm well, weak in the 5.2 nm well, and absent in the 10.4 nm well. Pressure coefficients of PL lines have been used to estimate the electric field in the wells. In the widest well, the field seems to be fully screened (at high excitation powers). Simulations involving Poisson and Schrödinger equations allowed us to identify the experimental PL lines. Pressure evolution of the PL spectra agreed with the simulation. We present diagrams showing the dependence of the field in the well on pressure and on carrier concentration. In wide wells, these diagrams illustrate the transition from a 2D-like system to a 3D-like system. Full article

Colloidal quantum dots (CQDs) are ideal for room-temperature gas sensors due to their high surface area, abundant dangling bonds, and excellent film-forming properties. However, the underlying conduction mechanism remains unclear, lacking in-depth analysis of gas–solid charge transfer and carrier transport, which hinders the rational design of high-performance gas sensors. To address this, we fabricated a PbS colloidal quantum dot thin-film transistor (TFT) gas sensor that enables in situ analysis of carrier concentration and mobility via gate voltage modulation. We systematically measured the variations in conductivity, carrier concentration, and mobility with NO₂ concentration and established a normalized weight variation model. The results show that the conductivity increase upon NO₂ exposure is primarily due to the rise in carrier concentration induced by gas adsorption. At low concentrations (below 0.5 ppm), the response is dominated by mobility variation. This work provides a physically meaningful theoretical framework for understanding the conduction mechanism. Full article

Lithium-ion batteries have become crucial energy carriers in multiple core fields owing to their excellent comprehensive performance. Nevertheless, as battery energy and power densities continue to rise and operating conditions grow increasingly complex, thermal safety issues have become increasingly prominent. Immersion liquid cooling technology has attracted widespread attention in academic and engineering fields for its outstanding heat transfer and temperature uniformity performance. As a core component of this technology, the selection of liquid coolants is of vital importance. Various coolants investigated in existing studies generally suffer from limitations to varying degrees. Against this backdrop, intrinsically safe fluorocarbon C₇H₄F₁₂O (3F-135) serves as an ideal liquid cooling medium for lithium-ion batteries, thanks to its high thermal stability, superior electrical insulation and environmental friendliness (zero ODP, extremely low GWP). However, its decomposition mechanism and reaction pathways under extreme thermal runaway conditions of batteries remain unclear. In this study, a tube furnace was adopted to simulate high-temperature environments induced by thermal runaway, and gas chromatography–mass spectrometry (GC-MS) was employed to analyze decomposition products and decomposition ratios of 3F-135. Subsequently, density functional theory (DFT) calculations were utilized to construct the pyrolysis reaction network of 3F-135. Ultimately, the dominant pyrolysis pathways in different temperature ranges were clarified, providing theoretical support for the application and selection of intrinsically safe liquid coolants. Full article

CO₂ gas-line absorption is emerging as a major L-band impairment in low-loss hollow-core fiber (HCF) links. We compare two transponder-side mitigation strategies—spectral pre-emphasis and spectral avoidance—over span lengths of 100–300 km and transmission reach of up to 3000 km. The preferred strategy depends on reach, launch power, span length, and the stability of the live-link absorption comb. Pre-emphasis is favored at short reach and for short spans, whereas spectral avoidance is superior at moderate to long reach, with a peak capacity gain of about 4 Tb/s. Pre-emphasis is also more sensitive to mismatch between the design-time and live-link absorption combs: increasing the live absorption peak from 0.10 to 0.35 dB/km reduces capacity by up to 8.5 Tb/s, while tripling the CO₂ absorption linewidth reduces capacity by up to 10.3 Tb/s. We further review implementation options for both methods: DGFF-based pre-emphasis at the WSS sites, and DSP-based avoidance via digital subcarrier multiplexing (DSCM) or entropy-loaded orthogonal frequency-division multiplexing (OFDM). These results provide a concise framework for selecting mitigation strategy under realistic operating conditions. Full article

Two-dimensional molybdenum disulfide (MoS₂) has emerged as a promising candidate for next-generation electronics and optoelectronics; however, its scalable synthesis with precise control over domain size and film continuity remains challenging. Herein, we report a physical vapor deposition (PVD)-assisted chemical vapor deposition (CVD) strategy for the controllable growth of high-quality monolayer MoS₂. By thermally evaporating an ultrathin (3 nm) MoO₃ precursor film, spontaneous post-deposition dewetting yields a porous honeycomb morphology that significantly enhances vapor–solid reaction kinetics during subsequent sulfurization. Crucially, by modulating the argon carrier gas flow rate to regulate the local sulfur chemical potential, we achieve distinct growth regimes: a high flow rate (70 sccm) suppresses nucleation density, enabling isolated triangular and hexagonal single crystals with lateral dimensions up to 500 μm, whereas a reduced flow rate (50 sccm) promotes high-density nucleation and coalescence into continuous centimeter-scale polycrystalline films. Comprehensive structural and optical characterizations, including atomic force microscopy, Raman spectroscopy, photoluminescence, and X-ray photoelectron spectroscopy, confirm that the synthesized MoS₂ exhibits prototypical monolayer thickness (~0.7 nm), well-defined local crystallinity and a direct bandgap emission at 1.84 eV. This work establishes a robust, scalable, and highly tunable route for synthesizing large-area 2D TMDs tailored for advanced device integration. Full article

This work presents the thermodynamic design and performance assessment of an integrated process line for the separation, liquefaction, storage, and valorization of carbon dioxide (CO₂) and nitrogen (N₂) from flue gas streams. The proposed system aims to combine carbon capture with cryogenic energy storage by exploiting the thermophysical properties of the main flue gas constituents. A representative flue gas derived from complete methane combustion (9.5% CO₂, 71.5% N₂, and 19% H₂O by volume) is considered as the feed stream. The process is developed and simulated in DWSIM v9.0.5, adopting a steady-state mass and energy balance framework coupled with rigorous thermodynamic modeling of phase equilibria and unit operations. The plant configuration is based on sequential cooling, compression, and expansion stages, enabling the selective condensation of H₂O, CO₂, and N₂ at different temperature levels. The system integrates heat exchangers, compressors, pumps, turboexpanders, phase separators, and cryogenic storage tanks, while a portion of the liquefied CO₂ is reused as an energy carrier through vaporization and expansion in a dedicated turbine. The results demonstrate that the process achieves a CO₂ capture ratio of 81.7%, with a specific electric consumption (SEC) of 10.44 kWh/kg_CO2 and 1.71 kWh/kg_N2. The overall net electric demand is 1.29 kWh/kg of treated flue gas, while the round-trip efficiency (η_RT,CO2) is 18.6%. A significant amount of energy can further be recovered from the “waste” exhaust water stream (12.94 kg_L-H2O/kg_flue-gas, at 91 °C and 1.2 bar) up to 800 Wh/kg_flue-gas, improving the performance of the entire process (SEC_CO2: 3.86 kWh/kg_CO2, η_RT,CO2: 69.8%). The study confirms the thermodynamic feasibility of the proposed configuration and identifies nitrogen liquefaction as the dominant energy-intensive step. Future optimization efforts should therefore focus on reducing exergy destruction in the deep cryogenic section through improved heat integration, enhanced cold-energy recovery, optimized compression–expansion staging, and reduced pressure losses. Full article

This study systematically investigates the intrinsic vertical breakdown characteristics of 8-inch GaN-on-Si high-electron-mobility transistor (HEMT) buffer layers (extending up to the GaN channel layer) using a vertical electrode configuration. By comparing samples with different carbon doping doses, AlN insertion layers, and superlattice cycle numbers (buffer layer thickness), combined with Technology Computer-Aided Design (TCAD) simulations, the relevant mechanisms are revealed. The results show that buffer layer thickness is a critical factor determining the vertical breakdown voltage. Its increase effectively reduces the longitudinal average electric field, widens the depletion region, and increases the breakdown voltage by approximately 50%. Carbon doping compensates for carriers and suppresses leakage through deep-level acceptor traps. Inserting thin AlN layers into the superlattice has a limited effect on improving breakdown voltage. This research provides clear experimental guidance for the optimal design of high-voltage GaN HEMT buffer layers from both material and physical perspectives. Full article