Search Results (997)

To improve the effectiveness of sulfonated polyacrylamide soft microgels (SMGs) in deep profile control, this study investigated a surfactant-assisted regulation strategy based on surfactant uptake and surfactant–microgel association. The uptake behavior of a hydroxysulfobetaine surfactant by SMGs was characterized, and the resulting changes in swelling, frequency-dependent elastic response, electrostatic stabilization, shear resistance, and long-distance transport were evaluated. The surfactant uptake process was well described by pseudo-second-order kinetics and a Langmuir-type saturation model, while FTIR and XPS analyses provided spectroscopic evidence for surfactant association with SMGs, especially at the particle surface. Compared with the SMG system, surfactant addition mildly reduced the swollen median size (D₅₀) at 15 d from 15.72 to 14.90 μm, and the corresponding swelling ratio decreased slightly but remained above 6.45. The S/SMG system also showed a larger magnitude of negative zeta potential, maintaining a value of −38.5 mV after 60 d compared with −32.1 mV for the SMG system, and generally better shear resistance, with particle size retention 0.8–3.8 percentage points higher over 0–7 d of swelling. Serial core-flooding experiments showed improved deep transport behavior. Although the SMG system produced slightly higher injection pressure below 2.4 m, the S/SMG system maintained a slightly higher pressure response beyond this distance. These results demonstrate that surfactant uptake and surface/network association regulate SMG physicochemical properties, thereby improving their transport and deep profile-control performance. Full article

Large-scale disasters can result in chronic pollution of coastal environments with unanticipated and poorly quantified impacts, such as the reshaping of marine connectivity. A recent example is the collapse of the Fundão tailings dam in 2015, which released about 50 million m³ of mine waste into the Doce River, affecting one of Brazil’s largest estuarine–mangrove systems. Here, we combine a high-resolution CROCO hydrodynamic simulation with an individual-based Lagrangian model (Ichthyop) to track the dispersal of mangrove crab (Ucides cordatus) larvae from four estuaries along the southeastern Brazilian margin between 2022 and 2024. Trajectories crossing seasonal msPAF fields derived from in situ water-quality measurements were used to quantify larval exposure to contaminants from mine waste. These fields were based on measured concentrations of As, Ba, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, V, Zn, and Al. Results show that surface shelf flow and mesoscale activity in the vicinity of the Doce River mouth contribute to offshore export of larvae, while the reef-dominated Abrolhos shelf promotes retention. Interannual variability alternates between long-distance export and local retention, associated with regional climate variability. Larval mortality rates caused by offshore advection and lethal temperature are high (65–75%). In addition to these modeled mortality sources, surviving cohorts frequently crossed areas with elevated msPAF values during transport, indicating potential exposure to metal(loid) mixtures. This suggests that the regional connectivity of U. cordatus is under chronic stress that likely compromises the integrity and resilience of coastal populations, since southern estuaries depend strongly on northern larval sources. The integration of Lagrangian simulations with in situ contaminant monitoring and spatially explicit exposure metrics demonstrates that transport pathways regulate not only connectivity among estuaries but also the duration and intensity of larval exposure to pollutants. Full article

Offshore oil and gas exploitation is one of the riskiest businesses to invest in and is dominated by various uncertainties: high deepwater pressure, low temperatures, remote operation, long-distance tiebacks and transportation, as well as environmental factors such as wind, waves and ocean currents. Serving as a profitability threshold, the minimum economic field size is defined as the economic recoverable reserve level that an oilfield must exceed to achieve economic returns. This paper develops an approach for determining the minimum economic field size of offshore oil and gas reservoirs. It categorizes the capital expenditure into four major components: drilling and completion costs, platform costs, pipeline costs, and subsea production system costs. The regression models of drilling costs and subsea production costs are developed respectively, with water depth and recoverable reserves as key influencing factors. The pipeline costs are estimated using the unit pipeline cost per mile and pipeline length. A profit model for the offshore field is established under the constraints of the contract, which allocates the oilfield’s production profits between the contractor and the government according to the contractual fiscal terms. Finally, taking the Lucius oilfield in the Gulf of Mexico as a case study, the paper simulates its investment, operating costs, and oilfield revenues. The minimum economic field size is calculated, accompanied by the derivation of the sensitivity boundaries for the primary parameters. Full article

Carbon capture and storage (CCS) is widely recognized as a key technology for reducing carbon dioxide (CO₂) emissions from large industrial sources. Among the stages of the CCS chain, CO₂ transportation plays a decisive role in determining overall system safety, reliability, and economic viability. CO₂ transportation through pipelines is generally preferred for large-scale, long-distance applications and is commonly operated under dense or supercritical conditions to maximize efficiency. However, internal corrosion of pipeline steels remains a major integrity concern, with corrosion accounting for approximately 45% of reported CO₂ pipeline failures. This review provides a comprehensive assessment of internal uniform and localized corrosion phenomena in CO₂ pipelines operating under supercritical CO₂ environments. The influence of key CO₂ stream impurities, including H₂O, O₂, H₂S, SO_x, and NO₂, is examined, considering their individual and synergistic effects on corrosion mechanisms, corrosion morphology, corrosion products, and severity ranking. In addition, an in-depth analysis of operating parameters such as temperature, pressure, flow conditions, and exposure time is presented alongside material-related factors, including steel grade, internal surface roughness, and welded regions. Corrosion mitigation approaches are also reviewed, with particular emphasis on organic, inorganic, and composite corrosion inhibitors. The review concludes by identifying key knowledge gaps and outlining future perspectives for improving corrosion control in CO₂ transport systems supporting large-scale CCS deployment. Full article

This study focuses on a large rubber-tired gantry crane (RTGC) operating in a nomadic prefabricated beam yard and develops a Digital Twin-driven dynamic feasible route planning method for the path planning problem under the combined effects of a discrete topological road network, dynamic road occupation, time-window constraints, and right-of-way priority rules. By integrating the existing digitalized yard management system with field-acquired data, an operational-stage updating mechanism for dynamic topology and time windows is established. On this basis, long-vehicle occupancy, time-window constraints, and right-of-way priority rules are embedded into the A* search and rolling replanning process, forming a Digital Twin-based dynamic A* (TD-A*) feasible route planning algorithm under evolving operational constraints. Results from a representative operational case show that, under long-path conditions with significant dynamic constraints, TD-A* reduces transportation distance by 16.8% and operation time by 18.9%. For the full-process results, the transportation distance is reduced by 16.4%, the operation time by 12.8%, and the number of turning maneuvers by 50.0%. The results demonstrate that the proposed method can improve the adaptability of feasible route planning to dynamic road occupation and traffic conflicts in a real nomadic beam yard with a single RTGC, and demonstrate the engineering feasibility of embedding Digital Twin-driven dynamic constraints into the route planning process. Full article

The imbalance between water supply and demand is intensified by population growth and economic development. While water diversion projects are capable of mitigating water shortages, multiple ecological and environmental risks, such as accidental pollution and impairment of ecosystem structure, are introduced by their long-distance water transport and complex corridor environments. The reduction in potential losses hinges on the accurate assessment of these risks. This study integrates the Driving Force–Pressure–State–Impact–Response (DPSIR) model with a projection pursuit model optimized by an improved Sparrow Search Algorithm (SSA) based on seagull optimization and whale optimization operators. A comprehensive risk assessment model was constructed and validated using data from the Chuhe Main Canal for the period 2015 to 2024 as a case study. The results indicate that “water resource utilization rate”, “biodiversity index”, and “public satisfaction” are key factors; project risks have gradually escalated from “relatively low risk” to “relatively high risk”. By this model, the key risk factors and evolutionary patterns of ecological and environmental risks in water diversion projects are able to be scientifically identified, thereby providing a quantitative basis for risk early warning and differentiated management strategies, as well as serving as a reference for the ecological risk assessment of similar inter-basin water diversion projects. Full article

Maglev transportation has emerged as a new option for long-distance travel between cities with the rapid development of transportation infrastructure. The fatigue issues of the maglev train–track–bridge coupling system, induced by increased train speeds, have garnered considerable attention. This study focuses on the continuous girder bridge of low-to-medium-speed maglev dedicated lines. A multi-vehicle coupling model and a refined vehicle–track–bridge system were constructed. These were based on the maglev equivalent stiffness-damping theory. Dynamic stress is solved using the modal superposition method. Fatigue performance under multiple working conditions is then evaluated. This evaluation uses the rainflow counting method and Miner’s linear damage theory. Dynamic stress is solved using the modal superposition method, and fatigue performance under multiple working conditions is evaluated based on the rainflow counting method and Miner’s linear damage theory. Key findings include the following: Dynamic stress peaks in the track structure reach 29.4 MPa at high-strength bolts and 20.1 MPa at bridge fasteners, significantly exceeding those in the bridge, identifying these as fatigue-sensitive zones. During a single train passage, the stress amplitudes are mainly concentrated in the low-stress amplitude range, yet annual accumulated damage at the critical node track tie and bridge fastener junction reaches 4.99 × 10⁻⁴. Increasing the train speed to 160 km/h amplifies total damage at the track tie and bridge fastener junction by 365%, with nonlinear growth in fastener damage. This research provides theoretical insights for optimizing speed-up strategies and maintenance protocols in low-to-medium-speed maglev systems. Full article

Research increasingly identifies wild birds, particularly long-distance migratory species, as epidemiologically relevant hosts and vectors for tick-borne Borrelia species that pose risks to both avian and human health. This review contextualizes avian-associated Borrelia research historically and microbiologically, showing the role of avian hosts in the ecology of agents causing relapsing fever and Lyme borreliosis. We identify key publications that trace the evolution of Borrelia research—from early microscopic observations of spirochetes to the modern molecular and serological evidence. The review collects literature on the process by which Borrelia gained early scientific attention due to its characteristic morphology and elevated bloodstream concentrations during septicemic phases, which enabled early etiological links between the microbe and disease. It follows the recognition of avian spirochetosis caused by Borrelia anserina and charts the shift in focus after the discovery of Borrelia burgdorferi sensu lato (Subgen. novum recomm. Borreliella, Lyme-group Borrelia). Publications listed show that birds can transport infected human-parasitic ticks over long distances and, in certain bird species, selectively amplify Lyme-group Borrelia species, especially Borrelia garinii, which has the highest temperature tolerance and is thus potentially viable in avian hosts. The literature supports the role of birds in maintaining and disseminating Borrelia infections and infected ticks across continents. Full article

The growing demand for long-distance green methanol transportation highlights the critical need to evaluate the safety and reliability of pipeline sealing materials. This study investigates the swelling mechanisms of fluorocarbon rubber (FKM), nitrile butadiene rubber (NBR), and polytetrafluoroethylene (PTFE) under simulated methanol pipeline conditions. Static immersion tests were conducted under simulated pipeline conditions with water contents of 0–20% and temperatures of 25–55 °C, supplemented by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and gas chromatography–mass spectrometry (GC–MS). FKM exhibited severe physical swelling, with the volume increase reaching up to 80% in pure methanol. Notably, the addition of 5% water markedly suppressed this swelling, reducing the volume change of FKM sealing rings to approximately 3% and the mass change to 1%. Conversely, NBR experienced volume shrinkage and mass loss due to the extraction of the plasticizer Bis(2-ethylhexyl) phthalate by methanol, a process also inhibited by water. PTFE demonstrated exceptional chemical stability and negligible dimensional changes owing to its high crystallinity and rigid structure. Consequently, PTFE is recommended as the optimal sealing material for pure methanol pipelines. When utilizing FKM or NBR, strict control over the fluid’s water content and operating temperature is essential to prevent degradation and ensure long-term pipeline integrity. Full article

Atmospheric sea spray aerosol (SSA) undergoes chemical aging during long-distance transport, leading to significant alterations in its climate effects. However, the aging mechanisms of SSA driven by oxygenated volatile organic compounds (OVOCs) remain unclear. Hence, the aging processes of NaCl particles driven by glyoxal (GL), a representative OVOC, are systematically investigated using molecular dynamics (MD) simulations and density functional theory (DFT) calculations. MD simulations with high GL coverage show that GL readily mixes with NaCl and preferentially orients its carbonyl groups toward the NaCl surface. The adsorption of GL on the NaCl surface is dominated by the interaction between the O atom of GL (O_GL) and the Na atom of the surface. DFT calculations with single GL coverage further reveal the formation of the O_GL–Na bond between GL and NaCl. The mixing process of GL and NaCl is regulated by both the number of aldehyde groups engaging in the interfacial coordination and the corresponding lengths of O_GL–Na bonds. The subsequent heterogeneous oxidation of GL by an OH radical proceeds mainly via a barrierless H-abstraction pathway to form HC(O)CO radicals, which may further react with methylamine/ammonia and contribute to brown carbon formation. Our results reveal the importance of incorporating such aging mechanisms into atmospheric models to improve climate predictions. Full article

This study examines the economics of blue and green hydrogen as feedstock for large industrial facilities in Southeast Asia. To understand how industries can adopt low-emission and renewable hydrogen, the levelised costs of blue and green hydrogen are calculated. Four pathways are examined, including a large-scale carbon capture and sequestration facility located a distance away from an existing steam methane reforming hydrogen plant, a gigawatt-scale electrolysis facility adjacent to a large industrial site fed by an adjacent solar photovoltaic electricity source, as well as two pathways with either remote electrolyser and solar photovoltaic, necessitating hydrogen transport and storage, or a remote solar photovoltaic source with a dedicated power transmission line. The region’s transition to green hydrogen must overcome the challenges of high renewable electricity costs, the need for large land banks for solar photovoltaic farms and efficient long-distance hydrogen transport solutions or power transmission lines. Moreover, the region must improve its inconsistent track record in implementing billion-dollar public–private projects within budget and on time. Full article

The particle size distribution of backfill aggregate is a key factor affecting the performance of the -long-distance pipeline transport of backfill slurry. However, the understanding of its impact on slurry flow behavior, transportation resistance, and particle distribution mechanisms remains incomplete and calls for further investigation. This study first obtained the rheological parameters of slurry and their variation laws under the influence of particle size distribution through rheological experiments. Subsequently, CFD numerical simulations are used to investigate the flow characteristics of slurry under long-distance transportation conditions. The findings demonstrate that a reduction in the mixed aggregate particle size leads to a significant increase in both the yield stress and plastic viscosity of the backfill slurry. The conveying distance shows a positive correlation with the slurry transportation resistance. Furthermore, the slurry exhibits plug flow behavior in both the horizontal and vertical pipe sections, whereas this plug flow pattern is no longer observed in the bend section. The tailings particles exhibit a distinct stratified distribution within the pipeline. In the horizontal pipe section, the graded tailings predominantly settle at the bottom, whereas the fine tailings remain suspended near the top. In contrast, in the vertical pipe section, the graded tailings tend to accumulate in the central zone of the pipe, while the fine tailings are dispersed along the pipe wall. As the content of graded tailings increases from 30% to 50%, both the zones with increased and decreased particle volume fractions expand, while the steady flow zone correspondingly shrinks. Meanwhile, the volume fraction of graded tailings at the bottom of the pipe rises significantly from 0.12 to 0.61. This research provides important theoretical support for the optimized matching and rational application of tailings particle size distribution in the design of long-distance pipeline transportation systems for mine backfill. Full article

With the advancement of the “dual carbon” goals, the electric vehicle market has experienced explosive growth, and user review mining has become key data support for industrial quality improvement and low-carbon transportation transition. Addressing the limitations of existing sentiment classification methods in long-distance feature capture, cross-sentence semantic association, and emotional feature focus, this study proposes a BERT-Bi-xLSTM-Attention fusion model: BERT pre-trained semantic representation extracts deep contextual information, Bi-xLSTM models long-range dependency relationships, and the Attention mechanism locates sentiment-critical markers. Based on multi-platform review data from Chinese Autohome, Yiche, and China Quality Inspection Network, experiments show that the model achieves Accuracy, Recall, Precision, and F1 values of 0.9323, 0.9326, 0.9321, and 0.9328, significantly outperforming baseline models. A “sentiment-topic” fusion analysis framework is constructed, identifying five positive themes and four negative themes, revealing the dual emotional characteristics of range, driving experience, and smart features. Temporal analysis finds that negative attention to intelligent system reliability has continued to rise from 2021 to 2024, becoming an emerging user pain point. Combined with the above findings, it is recommended that consumers comprehensively evaluate multi-attribute experiences when purchasing; manufacturers prioritize optimizing user-concerned attributes; and policymakers improve industrial standards and regulatory mechanisms. This promotes high-quality development of electric vehicles, contributes to the realization of carbon neutrality goals in the transportation sector, and facilitates sustainable transportation development. Full article

Maintaining asphalt pavements requires substantial quantities of materials and energy, which significantly contribute to greenhouse gas emissions in the road infrastructure sector. This study quantified the carbon dioxide equivalent (CO₂e) emissions associated with a maintenance and rehabilitation plan for an asphalt pavement using a simplified life-cycle perspective integrated with the Highway Development and Management Model (HDM-4). The methodology combined HDM-4 to define a 35-year intervention plan (2022–2057) with CO₂e emission factors for three quantified components: material production, transportation, and construction machinery operation. The approach was applied to a 7.8 km section of the Mexicali–San Felipe highway in Baja California, Mexico. The results indicate that the intervention plan generated approximately 2483.9 t CO₂e over the 35-year analysis period. Reconstruction was the most carbon-intensive activity, accounting for 1890 t CO₂e, while milling and overlay generated 292.15 t CO₂e per direction. Material extraction and production were the dominant sources of emissions, contributing about 70% of the total emissions in milling and overlay and 60% in reconstruction; in the latter case, transportation also represented a substantial share (35%) due to long haul distances. These findings show that the proposed approach can identify the most emission-intensive activities and processes within pavement maintenance plans and provide quantitative environmental criteria to support more sustainable road management decisions. Full article

Background: Tuberculosis (TB) remains a major public health challenge globally, particularly in high-burden countries such as South Africa. Treatment interruption is a critical barrier to effective TB control, contributing to poor treatment outcomes, increased risk of multidrug-resistant tuberculosis (MDR-TB), and continued community transmission. Understanding the determinants of treatment interruption in rural healthcare settings is essential for strengthening TB programme implementation. Methods: This qualitative study explored the factors influencing TB treatment interruption from the perspectives of professional nurses working in primary healthcare facilities in the Nyandeni Subdistrict, Eastern Cape, South Africa. Semi-structured interviews were conducted with nurses involved in TB programme implementation. Data were analysed using thematic analysis following the six-phase approach described by Braun and Clarke. Descriptive statistical analyses were also used to summarize participant characteristics, including age and years of nursing experience. Conceptual frameworks were developed to illustrate the multilevel determinants of TB treatment interruption. Results: Participants had a mean age of 40.6 years and an average of 14.2 years of nursing experience, reflecting a workforce with substantial clinical exposure to TB management. Thematic analysis identified multiple interconnected determinants of treatment interruption. Key barriers included poverty, food insecurity, transport costs, long distances to healthcare facilities, limited family support, and challenges related to patient tracing. These factors interact across structural, community, health system, and interpersonal levels to influence patient adherence behaviour. Conceptual models developed from the findings illustrate the complex pathways through which these determinants contribute to treatment interruption and programme-level consequences such as reduced treatment success and increased risk of MDR-TB. Conclusions: TB treatment interruption in rural settings is driven by multilevel socioeconomic and health system determinants rather than individual patient behaviour alone. Strengthening community health worker programmes, improving patient tracing systems, addressing socioeconomic barriers, and enhancing community-based support mechanisms are essential for improving treatment adherence. Integrated, multisectoral interventions are required to strengthen TB programme outcomes in rural high-burden settings. Full article