A key parameter that affects dislocation motion, deformation mechanisms, and the overall mechanical response of face-centered cubic (FCC) metals is stacking fault energy (SFE). The study aims to investigate the effect of stacking faults (SF) on the mechanical properties of copper (Cu) using molecular dynamics (MD) simulations. In this work, the Embedded Atom Method (EAM) interatomic Cu-Cu (Mishin et. al.) potential is employed to model the interactions in Cu, while a combination of tensile testing and the introduction of stacking faults allows for the simultaneous analysis of mechanical behavior and SFE. The results reveal a direct correlation between various parameters like stacking fault, temperature, and system size which subsequently influences the material's ductility, stress-strain response, and failure mechanisms. This study provides insights into the temperature and size dependent mechanical behavior of Cu, with potential implications for understanding deformation in other FCC metals.
INCONEL 600 is extensively employed across various industries due to its remarkable resistance to both corrosion and elevated temperatures. The alloy’s superior high-temperature performance and extended service life are largely attributed to its stable single-phase microstructure, which remains intact up to 1703 K (1430 ℃). In this study, the microstructural evolution of INCONEL Alloy 600 was systematically examined under a range of thermal and thermomechanical treatments. These microstructural analyses were complemented by mechanical property assessments, including tensile and creep tests. Specimens were solutionized at 1200ºC for 1 h, resulting in a microstructure characterized by an average grain size distribution between 45–60 μm. Additionally, primary and secondary carbides rich in Cr, Nb, and Ti were observed within the γ matrix. The alloy was subsequently subjected to cold forging at room temperature, with varying levels of strain ranging from 20
Many critical process parameters affect the fatigue performance of super alloys produced by Selective Laser Melting (SLM). These parameters affect the microstructure, surface roughness, and defect formation and play a significant role on the fatigue life of the super alloys. Optimizing these parameters in combination with appropriate post-processing techniques is crucial to extending fatigue life by decreasing defects. In the present work two set of Inconel718 (IN718) samples were prepared under two different energy densities. According to ASTM E606, a low cycle fatigue test is conducted to assess fatigue performance. Samples with lower energy density showed better fatigue life (Nf) of 858 number of cycles under strain amplitude of 0.8
The hydrogen electric coupling system (HECS) is an indispensable component of next generation power systems, with safety being a prerequisite for its deployment. However, existing studies have conducted limited analysis on the safety of HECS. This study comprehensively investigated the safety risks and accident consequences of HECS. 75 potential failure modes were identified by Failure Mode and Effects Analysis (FMEA), with electrical issues and sealing problems emerging as key contributors to medium and high-risk accidents, respectively. Event Tree Analysis (ETA) were employed to elucidate the main causes and logical chains leading to combustion. Results showed that ignition sources in the environment are the primary triggers, and the hydrogen compression system had a high accident frequency. Numerical simulations of hydrogen leakage and dispersion in confined spaces were conducted, enabling quantitative evaluation of jet fire, flash fire, and explosion consequences. The simulations revealed that hydrogen initially dispersed along the leakage direction, spread laterally upon encountering walls, and finally accumulated near the ceiling. Integrating consequence analysis with risk assessment standards, we found that the greatest injury distance (15.2 m ignition at 5.01 s) caused by the hydrogen storage system explosion, followed by the hydrogen production system (9.5 m ignition at 8.01 s). The maximum injury distances for the compression system and fuel cell system are 7.5 m and 6.7 m, respectively. This research provided critical insights into hazard sources and injury distances in HECS, laying the foundation for safety measure development.
To investigate the mechanism of formation damage induced by clay-free reservoir drilling fluids, a clay-free oil reservoir drilling fluid system was selected as the research object. Core displacement experiments and filter cake mechanical property tests were conducted by regulating the filter cake composition and varying the differential pressure during core displacement. The effects of filter cake composition, filter cake strength, and invasion depth on formation damage were then systematically analyzed. The results show that the filter cake composition has a significant effect on formation damage. In particular, the bridging and plugging structure formed by ultrafine calcium carbonate particles at pore throats is the main cause of formation damage. The influence of different components on formation damage follows the order ASP1250 > XCD > ASR-1. As the polymer effect in the drilling fluid system becomes stronger, the filter cake structure gradually changes from particle packing to a polymer network structure. The maximum load of the filter cake increases from approximately 15 N to more than 25 N, while the filtration volume increases from approximately 11–48 mL, indicating a positive correlation between filter cake strength and filtration volume. As the displacement pressure increases from 500 to 1500 psi, the core damage rate increases from 90.58 to 99.64
This paper firstly investigates the equivalent model of variable-speed pumped storage units and puts forward the corresponding mathematical models and control strategies for these units. With the aid of the Simulink simulation platform, a simulation model of the generator-motor for variable-speed pumped storage units and its supporting AC excitation system is established. On this foundation, a full-process hydro-mechanical-grid dynamic simulation system for variable-speed pumped storage units is constructed. This integrated system is composed of a multi-branch generator-motor, an AC excitation system, a pump-turbine together with its governing system, and an infinite power grid. The paper elaborates on all constituent parts of the dynamic simulation system and clarifies the specific functions and operational roles of each component. Meanwhile, a structural design scheme featuring multi-tap stator and rotor windings is proposed for the multi-branch dynamic simulation test motor. In the final stage, a series of tests targeting internal stator and rotor inter-turn short-circuit faults of the generator are carried out. The test results fully verify the accuracy and practical effectiveness of the developed system. The construction of this simulation system also provides a reliable experimental platform for simulating internal winding short-circuit faults and validating protection strategies of variable-speed pumped storage units.
The load-bearing performance of a pressure hull is one of the key factors controlling the operational depth and safety of deep-submersible vehicles. In this paper, a titanium-alloy spherical-cylindrical pressure hull reinforced with external T-shaped stiffeners was investigated under external hydrostatic pressure. A finite element model was developed in Patran, and both linear eigenvalue buckling analysis and nonlinear post-buckling analysis were carried out with Nastran. The eigenvalue analysis was used to identify the initial buckling characteristics, while the first buckling mode was introduced into the nonlinear model as an initial geometric imperfection. The ultimate critical pressure was then obtained by using the Riks arc-length method. The effects of stiffener size and stiffener number were examined in detail. The results indicate that enlarging the T-section stiffeners can significantly improve the buckling resistance of the hull, but the improvement becomes much smaller after the stiffener dimensions reach a relatively high level. Among the geometric parameters studied, the web height shows the most obvious influence on the ultimate pressure, whereas the flange width has a limited effect. Increasing the number of stiffeners also improves the structural stability, but excessive stiffeners may cause additional weight and manufacturing cost. Considering structural performance and engineering economy together, the pressure hull with four stiffeners is selected as a reasonable configuration. For this design, the nonlinear ultimate critical pressure is 20.29 MPa, which corresponds to an approximate limiting diving depth of 2029 m. The study can provide a reference for the design and assessment of titanium-alloy pressure hulls used in deep-sea vehicles and subsea engineering equipment.
Underground gas storage wells are widely used for large-scale gas storage and high-pressure gas storage at automotive refueling stations. Based on a review of relevant literature on gas storage wells, and incorporating the latest scientific research findings and inspection engineering practices, the current status of major inspection and testing technologies, as well as regulatory standards for gas storage wells are summarized. The technological development of hydrogen storage wells/hydrogen storage facilities, the technical challenges in inspecting and testing for hydrogen storage wells, and feasible testing technologies, and proposes recommendations regarding inspection and testing technologies for hydrogen storage wells are analyzed and discussed also.
Addressing the high-voltage, high-capacity, and compactness requirements of 300 MW-class large variable-speed pumped storage units, this paper systematically investigates key technologies of AC excitation systems, including power branch topology, IGBT voltage balancing, compact design methods, and control device architecture. Through comparative analysis of electrical characteristics and engineering applicability of various topologies such as two-level, NPC three-level, and MMC, the diode-clamped three-level (NPC) topology is selected as the optimal solution. To address the series voltage balancing issue of devices in medium-voltage high-power converters, an active voltage balancing strategy based on collector-emitter voltage integration is proposed, combined with RC passive damping snubber circuits, effectively suppressing voltage imbalance. In terms of compact design, a two-column three-level direct-series module structure and laminated busbar design scheme are proposed, significantly reducing parasitic inductance. Finally, the feasibility and reliability of the proposed solutions are verified through pulse tests, power-frequency back-to-back tests, and low-frequency back-to-back tests. The research results can provide technical support for the engineering application of AC excitation systems for large variable-speed pumped storage units.
In this research, the optical properties and gas sensitivity of the MAxFA1-xPbI3-based perovskite material were used to detect ammonia gas at low concentrations. The resulting optical sensor exhibits relatively strong and stable photoluminescence intensity and extends the luminescence response range for ammonia gas detection. It showed a linear relationship between the fluorescence intensity and ammonia gas concentration in the range of 20 ppm to 100 ppm. The developed optical sensor can be used for ammonia gas detection in a promising manner.
Traditional leak detection methods often suffer from reduced sensitivity and increased false alarm rates in cryogenic environments. This paper investigates and compares multiple leak detection technologies, selecting distributed fiber optic sensing technology to conduct experimental research on its feasibility for LNG pipeline leak monitoring. The results demonstrate that distributed fiber optic sensing technology offers advantages including high positioning accuracy, rapid response, speed, significant monitoring effectiveness, and excellent system stability and anti-interference capabilities, making it suitable for LNG pipeline leak detection. Based on the experimental findings, targeted recommendations are proposed for the application of distributed fiber optic online monitoring technology in LNG cryogenic pipelines, covering design, deployment strategies, and structural optimization.
Due to its high erosion efficiency and energy utilization efficiency, cavitation jet technology demonstrates broad application prospects in energy development fields such as oil and gas well drilling, reservoir stimulation, wellbore cleaning, and rock breaking. Dual-cavitation jet technology significantly enhances cavitation erosion performance by coupling two cavitation-inducing structures within the same nozzle. Based on this technology and considering geometric structural factors, three types of dual-cavitation nozzles are designed in this study: the angular–organ pipe cavitation jet nozzle (AOPCJN), the dual Helmholtz cavitation jet nozzle (DHCJN), and the angular–Helmholtz cavitation jet nozzle (AHCJN). Numerical simulations are conducted to investigate their flow field characteristics, while laboratory experiments are performed to evaluate their rock-breaking performance. The results show that AOPCJN exhibits continuous jet rock-breaking characteristics, whereas DHCJN and AHCJN exhibit pulsating jet characteristics. Under conditions of an injection pressure of 20 MPa, a confining pressure of 0.1 MPa, and a stand-off distance of 10d, AHCJN exhibits the best jet performance, characterized by the longest potential core, a peak wall pulse pressure approaching 20 MPa, a pulse amplitude of 6.88 MPa, and a pulse frequency of 2105 Hz, while its cavitation region can extend directly to the wall surface. In rock-breaking experiments conducted under the same conditions, AHCJN also demonstrates the best performance, producing a hole diameter of 15.03 mm, a depth of 45.58 mm, and an erosion mass of 18.33 g, with a relatively regular hole morphology. The results of this study provide a theoretical basis for the structural optimization of dual-cavitation jet nozzles.
To further investigate the effectiveness and application scope of digital radiography (DR) online inspection for liquefied natural gas (LNG) cryogenic pipelines, this experiment fabricated a series of stainless steel pipe specimens with typical defects, covering sizes below DN50 and ranging from DN600 to DN1000. DR inspection tests were conducted under various operating conditions to study the detection of defects and their impact on image quality under different conditions. The test results show that volume-type defects can be detected under all working conditions, while area-type defects can be detected under specific conditions. It can be seen that the application of DR online inspection for LNG cryogenic pipelines is feasible, but the image quality of LNG pipelines with a diameter of DN300 and above does not meet the standard requirements.
The scalable production of Mn3O4 is critical for sustainable metallurgy, yet the role of process design in its formation remains underexplored. This study examines the synthesis of Mn3O4 from industrial-grade MnCl2·4H2O via wet oxidative precipitation and dry thermal routes, focusing on oxidation mode, oxidant dosage, and additive effects. Wet methods yield phase-pure hausmannite, whereas the dry route introduces minor secondary phases due to nonuniform oxidation. Oxidation mode is identified as the dominant factor controlling particle formation: concurrent in-situ oxidation promotes rapid nucleation, producing ultrafine particles with narrow distribution, higher crystallinity, and lower lattice strain indicative of uniform growth. Additives such as PEG improve dispersion but play a secondary role. BET analysis confirms mesoporous structures with type IV isotherms and H3 hysteresis, arising from aggregation. These findings highlight nucleation-stage control as a key for Mn3O4 tuning, providing a process-oriented framework for its scalable production as a promising precursor for next-generation battery and electrochemical energy applications.
Chloride influences the concrete cover for RC decks in cold regions. This research aims to investigate the probability of chloride-induced corrosion (PCI) versus various chloride concentrations applied to the top part of the RC deck using two methods: the Monte Carlo simulation (MCS) method and the proposed approximate algorithm method (PAAM). The RC deck element used in this research is made of concrete consisting of 50
Monitoring the setting behaviour of geopolymer concrete (GPC) remains challenging due to the lack of reliable, non-destructive techniques capable of capturing its rapid and chemistry-dependent evolution. Existing methods provide limited insight into the dielectric response associated with geopolymerisation, creating a gap in real-time assessment of setting and reaction kinetics. This study proposes the use of a capacitive electrode method as a non-destructive tool to monitor and predict the setting and evolution of GPC. Several GPC mixtures were prepared by varying the alkaline solution–to–fly ash ratio (0.45–0.65) and the sodium silicate–to–alkaline solution ratio (0.65–0.85). Setting time was determined using penetration resistance, while dielectric constant (ε′) and loss factor (ε′′) were measured using a developed capacitive electrode cell. The results show that geopolymer evolution is most effectively monitored within the frequency range of 15–25 MHz, with ε′ and ε′′ providing a high-accuracy estimation of setting time. The dielectric constant (ε′) effectively captures overall geopolymer evolution, whereas the loss factor (ε′′) sensitively distinguishes reaction rates associated with different activator compositions. These findings demonstrate that the capacitive electrode method offers a rapid, accurate, and non-destructive approach for real-time monitoring of geopolymer concrete, supporting improved quality control and optimization of sustainable construction materials.
High entropy alloys (HEAs) are a new class of materials that consist of multiple principal elements in near-equal atomic proportions, exhibiting remarkable characteristics that make them particularly attractive for hydrogen storage. This area is becoming increasingly important as the quest for sustainable and efficient energy solutions continues. However, current hydrogen storage processes and the materials being utilized present significant challenges. Key issues include limited hydrogen absorption capacity, stability under varying operational conditions, and the ability to maintain performance over time. Refractory elements are identified as potential candidates for developing effective materials for hydrogen storage. In this study, density functional theory (DFT) is used to enhance our understanding of HEAs by investigating the structural, electronic and elastic properties of the ZrTiVNbCr and ZrTiVNbMo alloys before hydrogenation. Our investigations revealed that the ZrTiVNbCr and ZrTiVNbMo alloys primarily adopt a body-centered cubic (BCC) crystal structure. These alloys also demonstrated exceptional mechanical properties, including high tensile strength and resilience, which are crucial for ensuring their durability in demanding hydrogen storage applications. Findings highlight the significant potential of refractory HEAs in transforming hydrogen storage technologies. These materials not only promise enhanced storage capabilities but also present an opportunity to develop more efficient and sustainable energy solutions that can meet the growing demands of the global energy landscape.
This paper presents a critical narrative review of carbon emission reduction strategies in the asphalt industry, synthesizing evidence reported in published Life Cycle Assessment (LCA) and Life Cycle Cost Analysis (LCCA) studies. The review examines the environmental and economic implications of adopting eco-materials and alternative technologies, including warm mix asphalt (WMA), reclaimed asphalt pavement (RAP), fly ash, recycled polymers, and bio-based modifiers. Reported literature indicates that high reclaimed asphalt pavement (RAP) contents and warm mix asphalt (WMA) technologies can offer notable life-cycle cost savings and greenhouse gas emission reductions; however, the magnitude of these benefits varies significantly depending on system boundaries, assumptions, and regional contexts. Across the reviewed studies, reductions in asphalt production temperatures and increased utilization of recycled and waste-derived materials are consistently associated with lower energy consumption and reduced greenhouse gas emissions, while also supporting circular economy objectives. In parallel, LCCA-based evidence suggests potential long-term economic advantages through reduced material demand, lower production energy requirements, and enhanced pavement durability, although reported outcomes exhibit substantial variability. This review highlights key methodological trends, identifies limitations and inconsistencies in reported numerical results, and underscores the need for transparent, harmonized LCA/LCCA frameworks. By critically consolidating existing evidence, the paper clarifies both the potential and constraints of current carbon mitigation strategies in asphalt pavements and outlines priority directions for future research and policy-oriented implementation.
For over 15 years, Cameron University has conducted NanoExplorers, a ten-day residential STEM academy designed to introduce high school students to nanotechnology through materials science–centered, hands-on learning. The program emphasizes nanoscale structure–property–performance relationships using experiential learning modules in nanoparticle-based solar cells, superconducting materials, polymer nanocomposites, optical nanomaterials, DNA electrophoresis, and robotics. Students engage in authentic materials processing, device fabrication, and basic characterization while developing scientific communication, problem-solving, and teamwork skills. Program effectiveness was evaluated through participant surveys and longitudinal tracking of academic pathways over a three-year post-academy period. Results show that more than 50
Titanium dioxide (TiO2) is a widely studied semiconductor due to its chemical stability, non-toxicity, and strong photocatalytic activity. However, its wide band gap limits visible-light utilization, motivating efforts to modify its electronic structure through doping and nano structuring. The Pechini method was used to prepare carbon-doped titanium dioxide (C-TiO2). The diffraction peaks of the XRD pattern shows (101), (004) and (200) planes of tetragonal structure of TiO2 anatase. Lattice parameters, crystallite size, and micro-strain were obtained. The crystallite size decreased from 16.53 nm to 7.46 nm. Popa rules model gives anisotropic plot with different crystallite shapes. The absorption and reflectance spectra exhibited a pronounced red shift from the ultraviolet (UV) region toward the visible and near-infrared regions in the carbon-doped samples. This enhances photocatalytic activity by decreasing the band gap, which can be used in water treatment and hydrogen production and other photocatalytic applications. The estimated optical transition energy decreased from 3.13 eV to 1.25 eV. Therefore, this study aims to synthesize carbon-doped TiO2, investigate, and correlate the relation band gap and crystalline size.
