Search Results (3,543)

Seasonal permafrost areas undergo long-term freeze–thaw cycles, severely compromising the strength of foundation soils. Consequently, deformation and settlement under long-term cyclic traffic loads are greater than in normal temperature areas, leading to potential safety hazards. This study focuses on soft clay soils in seasonal permafrost areas. Remoulded soft clay is subjected to freeze–thaw cycles, followed by a series of long-term cyclic traffic load tests using the GDS dynamic triaxial testing system and pore size analyses using the nuclear magnetic resonance (NMR) technology. The study aims to investigate the effects of varying freeze–thaw cycles, compaction coefficients, and types of curing agents on the cumulative plastic strain of soft clay. The findings indicate that under identical freeze–thaw conditions, both the presence of curing agents and the increase of the soil’s compaction coefficient significantly restrain the deformation of freeze–thawed soils. In the micro perspective, freeze–thaw cycles cause irreversible fracturing of the soil’s internal framework, while the addition of curing agents effectively mitigates the pore enlargement effect. The resulting pore size distribution differs by about 4% from the original distribution, which is consistent with the patterns observed in dynamic triaxial tests. Full article

Background/Objectives: Osteoporosis and osteoarthritis are age-related musculoskeletal disorders with a high socio-health burden, affecting both healthcare systems and individuals’ quality of life. Both conditions are generally accompanied by a concomitant decline in muscle mass and strength, referred to as sarcopenia. In this context, tensiomyography emerges as a novel, non-invasive potential diagnostic strategy for assessing muscle quality, as this parameter influences the progression of both conditions. Methods: Histomorphometric and immunohistochemical analyses were performed on vastus lateralis muscle tissue obtained from patients undergoing surgery for femoral fracture affected by osteoporosis or osteopenia, patients operated for hip osteoarthritis, and patients undergoing hip arthroplasty for osteoarthritis, concomitantly affected by osteoporosis or osteopenia. In addition, muscle function was assessed in these patients using tensiomyographic analysis. Results: In osteoarthritic, osteoporotic, and osteopenic patients, a reduction in muscle quality and function was observed compared with the other two experimental groups, indicating an unfavorable effect of the coexistence of the two conditions on the muscular component. Furthermore, contraction time (Tc) measured by tensiomyography was negatively correlated with lumbar spine bone mineral density values and positively correlated with the percentage of type II muscle fibers. Conclusions: This study highlights how tensiomyography may represent a valuable non-invasive diagnostic strategy for assessing muscle status in osteoporotic and osteoarthritic patients, as it is able to detect muscle alterations that parallel the worsening of bone status and that cannot be inferred from simple biopsy analysis. Thus, tensiomyography could be considered a practical adjunct tool in the clinical assessment of musculoskeletal frailty. Full article

Background: Interpersonal violence is one of the most common causes of maxillofacial injuries. These injuries can range from minor soft-tissue injuries to serious, life-threatening conditions. This is particularly important when injuries occur in an exposed and vulnerable area of the body, such as the facial area. This study aimed to analyse the types of maxillofacial injuries, assess a profile of a typical victim of violence and determine the circumstances of the injury. Methods: A retrospective review was performed on the clinical data of patients managed for maxillofacial trauma resulting from interpersonal violence at the Department of Maxillofacial Surgery, University Clinical Hospital, Poznan, spanning the period from 2021 to 2025. Results: The study group included 510 patients, of which 95.41% were males, and the median age in the study group was 34 years. Furthermore, 14.71% of patients were under the influence of alcohol at the time of the violent incident. Most injuries occurred in 2022 (25.88%). Regarding months, June had the highest reported incidents (10.59%), while Saturday was the most injury-prone day (25.10%). The median days of hospitalisation in the study group was five. The mandible was the most frequently affected area. The most common types of fractures were single mandible fractures (30.59%) and double mandible fractures (27.25%). Most injuries were treated surgically (96.67%). In 10.20% of cases, the intervention of other specialists was needed. Conclusions: It is important to effectively prepare medical staff to receive patients with a history of interpersonal violence to diagnose and treat these types of injuries properly. Full article

Carbon-fiber-reinforced polymer (CFRP) cables have emerged as promising alternatives to conventional prestressing tendons because of their high tensile strength, excellent corrosion resistance, and low self-weight. Their use is particularly advantageous in infrastructure exposed to aggressive environments, such as chloride-induced corrosion, where improved durability and reduced maintenance are critically required. In this study, a 10 mm diameter round-bar-type CFRP cable was developed using a pultrusion process, and its applicability to structural systems was comprehensively evaluated through material testing and field implementation. Mechanical performance was assessed through tensile, relaxation, and fatigue tests. The developed CFRP cable exhibited an average tensile strength of 3019 MPa and an elastic modulus of 176.9 GPa, demonstrating mechanical properties comparable to or better than those of conventional prestressing tendons. The final relaxation ratio was measured as 2.25%, satisfying the low-relaxation criterion specified in KS D 7002. In the fatigue test, the cable sustained 2,000,000 loading cycles under a stress range corresponding to 60–66% of the ultimate tensile strength without fracture or significant stiffness degradation, confirming its excellent fatigue durability. In addition, the developed CFRP cable was implemented in a cable-net structure to verify its constructability and structural applicability in practice. The field application confirmed that the lightweight CFRP cable enabled convenient transportation and installation, while stable prestress introduction was achieved using the same tensioning procedure as that for conventional steel cable systems. The results demonstrate the integrated feasibility of the developed CFRP cable in terms of both material performance and practical structural application. This study provides experimental evidence supporting the structural use of CFRP tendons and offers a technical basis for the future development of design provisions and broader infrastructure applications. Full article

Tight oil reservoirs developed by volume fracturing commonly suffer from insufficient energy replenishment and rapid production decline. Although CO₂ huff-n-puff can enhance oil recovery, it is prone to early gas channeling through fracture-dominated high-permeability channels, and its effectiveness decreases with successive cycles. To clarify the coupled effects of fracture morphology and foam on CO₂ huff-n-puff performance, comparative experiments of multi-cycle CO₂ huff-n-puff and foam-assisted CO₂ huff-n-puff were conducted on fractured tight cores from the Xinjiang Mahu reservoir, combined with offline low-field NMR T₂ analysis. The results show a clear first-cycle dominant effect, and better reservoir properties lead to higher initial recovery and slower decline in subsequent cycles. Cross fractures increase the final oil recovery by 81.1%, 83.4%, and 73.2% for the three reservoir types, respectively, whereas excessively large fracture apertures reduce recovery because of intensified gas channeling. Foam further improves oil recovery, with 0.6% giving the optimum performance and increasing final recovery by 20.11%, 14.79%, and 8.36% in Type-I, Type-II, and Type-III reservoirs, respectively. NMR results indicate that foam mainly enhances the mobilization of remaining oil in medium and large pore–throat systems by blocking preferential flow channels and enlarging the effective swept volume. This study provides an experimental basis for parameter optimization and mechanistic understanding of foam-assisted CO2 huff-n-puff in fractured tight reservoirs. Full article

To investigate the mechanisms of coal seam reservoir modification and the efficient development of surface coalbed methane (CBM), the coal with different structural formations in the 13-1 coal seam of Huainan Mining Area was selected as the research object. Fracturing numerical simulation technology was employed to analyze the effect of hydraulic fracturing on tectonic coal reservoirs and explore the mechanism of fracturing-induced gas production. The results show that fragmented coal contains well-developed face and butt cleats, and distinct fracture models were constructed for the three tectonic coal types. Granulated and mylonitic structural coals exhibit larger total pore volumes and higher proportions of pores larger than 10 nm than fragmented coal. Both tectonic coal types exhibit a high proportion of methane flow space, with rapid methane desorption and diffusion under high pressure and stable behavior under low pressure. Pore volume compressibility calculations indicate that tectonic coal exhibits poor compressibility. Numerical simulations indicate that direct horizontal well fracturing produces short, wide fractures, whereas roof-strata horizontal well fracturing generates longer, more effective fractures, primarily due to large-scale depressurization and induced fracturing associated with horizontal well drilling and staged fracturing. Full article

The study systematically investigates the effect of molybdenum (Mo) content (0.70–1.57 wt.%) on the microstructure and mechanical properties of quenched and tempered martensitic steel for ultra-high-strength and -toughness oil well pipes. The results demonstrate that increasing the Mo content substantially enhances the strength of the steel. The yield strength (YS) increases from 1135 MPa to 1233 MPa, the ultimate tensile strength (UTS) rises from 1176 MPa to 1285 MPa, and the elongation after fracture is marginally improved to 19%. However, the low-temperature impact energy (AKV₂) of the steel at −20 °C exhibits a pronounced decrease, from 117 J to 36 J. Mo refines the multi-scale martensitic microstructure, increases the fraction of high-angle grain boundaries (HAGBs) and dislocation density, and promotes the precipitation of three types of carbides. Quantitative analysis indicates that grain refinement strengthening is the predominant factor contributing to the enhancement of steel strength. The decline in the steel’s resistance to low temperatures is attributed to the separation of coarse, blocky M₃C-type carbides at the grain boundaries. This results in the accumulation of stress at these boundaries, leading to a transformation in the steel’s fracture mode from ductile to brittle. Full article

This study investigates the effect of microstructure on water-induced embrittlement of dual-phase austempered ductile iron (ADI). Dual-phase ADI materials were produced by austenitization at 780, 800, 820, and 840 °C followed by austempering at 400 °C/1 h, resulting in microstructures composed of varying fractions of free ferrite and ausferrite. Tensile properties were evaluated under dry conditions and in distilled water. The embrittlement zones were observed in all samples investigated; however, they were not critical in all cases. The results indicate that free ferrite is less sensitive to water-induced embrittlement, whereas increasing ausferrite content promotes the formation and growth of the embrittlement zone. Elongation was identified as the most sensitive mechanical parameter, showing statistically significant reductions of up to ~80% for microstructures containing more than ~65% ausferrite, while proof strength remained largely unaffected. Fracture surface analysis revealed fatigue-like striation features within the embrittlement zone, indicating cyclic crack initiation and propagation. Based on correlations between tensile behavior, fracture morphology, and microstructural features, a water-induced embrittlement mechanism involving cyclic local chemisorption and surface-initiated crack growth is proposed. These findings highlight the critical roles of phase type, volume fraction, and spatial distribution in controlling the resistance of dual-phase ADI to embrittlement in aqueous environments. Full article

To overcome the drawbacks of conventional wedge cut blasting—high peak particle velocity (PPV), low blasthole utilization, and a high proportion of large fragments—this paper proposes a delayed blasting method for wedge cut blasting. By integrating the rock-fracturing process of wedge cut blasting, the mechanisms of rock breaking and vibration reduction are investigated and confirm the method through field tests. The results indicate that the rock breaking process can be divided into two stages, the stage of fracture propagation and the stage of cavity ejection, and a rock breaking criterion for wedge cut delayed blasting is established. Considering differences in the vibration waveforms generated by different types of cut holes, a vibration waveform fitting method for wedge cut delayed blasting is proposed. Furthermore, the generation time of the blast-induced free surface during the rock breaking process is calculated, and a calculation Equation for the optimal delayed time is derived. Field tests in the Qi Jiazhuang tunnel show that, compared with conventional blasting, the proposed delayed blasting method increases blasthole utilization by 23.8%, reduces the large fragment rate by 67.4%, lowers PPV by 53.7%, and increases the dominant vibration frequency by 42.0%. These results significantly improve the wedge cut blasting performance and construction safety. Full article

Plasma-facing materials (PFMs) for future fusion reactors require advanced mechanical and thermal properties to withstand the extreme challenges of high heat flux, plasma exposure, and neutron irradiation. Tungsten is one of the most suitable materials for use as a PFM in the divertor region. However, considering the high thermal loading/thermal stress combining plasma exposure and neutron irradiation/embrittlement, one of the major concerns for tungsten in PFMs is its intrinsic brittleness. To avoid cracking and components failure, tungsten toughening has been widely investigated, including the development of tungsten fiber-reinforced tungsten composites (W_f/W) using an extrinsic toughening mechanism, which could provide damage resilience against neutron embrittlement. Recently, a type of aligned long-fiber W_f/W (L-W_f/W) based on a powder metallurgical fabrication process was developed, demonstrating advanced fracture toughness while retaining other application-relevant properties. For L-W_f/W, the relatively easy production process suggests the feasibility and basis of industrialization. This work reports on the initial progress in industrializing L-W_f/W, with a focus on adapting the lab sintering process to a sintering process with industrial partner (Dr. Fritsch Sondermaschinen GmbH) and optimizing the process parameters. To improve the sinterability of tungsten and achieve higher density, various tungsten powders were explored, including commercial W powders, bimodal mixtures of different particle sizes, and granulated W powders. At the dedicated yttria interface, the thickness of yttria coating on the fibers was also optimized to ensure effective separation between the fibers and the matrix. Series of samples were produced with different dimensions up to 100 mm × 100 mm × 4 mm. After optimization, samples with 93% density and desired pseudo-ductility were prepared. Similarly to production in the lab, a major challenge in this work involved balancing the densification of the tungsten matrix with controlling fiber recrystallization and mitigating damage to the yttria interface. Full article

Glucocorticoids (GCs) are widely used for their potent anti-inflammatory and immunosuppressive effects, but their use is strongly associated with negative impacts on bone health. Rapid bone loss and an increased risk of fragility fractures are characteristics of glucocorticoid-induced osteoporosis (GIOP), the most common type of secondary osteoporosis. While oral GCs are a well-known cause of GIOP, growing evidence suggests that non-oral routes of administration may also negatively affect the skeleton. This review summarizes current knowledge on the pathophysiology of GIOP, highlighting the complex relationship between direct and indirect mechanisms. It examines the effects of various routes of GC administration—oral, intravenous, inhaled, topical, and epidural—on bone mineral density, microarchitecture, and fracture. While parenteral GCs may have fewer systemic effects than oral therapy, long-term exposure or high cumulative doses may still cause clinically significant skeletal deterioration. This review also discusses current methods for assessing, preventing, and treating the fracture risk associated with GIOP. These strategies include lifestyle modifications, calcium and vitamin D supplements, and medications such as denosumab, bisphosphonates, and anabolic agents. Reducing the incidence of glucocorticoid-associated fractures and improving prevention and treatment requires an understanding of how GCs impact bone. Full article

To achieve efficient development of medium-depth and shallow high-rank coalbed methane in the Qinshui Basin of Shanxi Province, the authors focused on the microscopic methane release mechanism. Through scanning electron microscopy, nuclear magnetic resonance, and isothermal adsorption experiments, the pore structure, distribution patterns, and influence of hydration effects in this type of coal were revealed. It was clarified that the ineffective utilization of “bound-state” methane within nanopores is the key factor leading to low productivity and efficiency in coalbed methane development. Further, based on molecular simulations, the competitive adsorption characteristics between water and methane molecules were quantified, indicating that about 78% of the methane in the internal pores of 4 nm coal molecular clusters cannot be desorbed through pressure reduction. Meanwhile, the production enhancement mechanism of hydraulic fracturing on coal seam depressurization, permeability enhancement, reduction in low-speed diffusion distance, and enhancement of high-speed linear flow was clarified. Through large-scale pad water injection and stepwise slow production increase, the coal seam can be fully communicated, the reservoir effectively stimulated, and the adsorbed methane sufficiently released. This paper establishes a “channeled” fracturing concept and its supporting technological system for medium-depth and shallow high-rank coal, which has been successfully applied in field operations. The pilot well group achieved stable daily production exceeding 50,000 cubic meters per day, laying a solid foundation for the continuous and stable production increase in medium-depth and shallow high-rank coalbed methane in the Qinshui Basin. Full article

Background: Calcaneal fractures are complex injuries frequently associated with significant soft tissue damage and a high risk of post-operative complications, particularly infection. Despite advances in surgical techniques, infectious complications remain a major cause of morbidity and can severely compromise functional outcomes. The aim of this systematic review was to analyze the incidence, management strategies, and clinical impact of infectious complications following surgical treatment of calcaneal fractures. Methods: A systematic literature search was conducted in MEDLINE, Scopus, and Web of Science in accordance with PRISMA guidelines, including studies published up to May 2025. Randomized controlled trials and prospective and retrospective cohort studies involving adult patients surgically treated for calcaneal fractures and reporting post-operative infectious outcomes were included. Data extraction focused on patient demographics, fracture characteristics, surgical techniques, infection rates, microbiological findings, management strategies, complications, and functional outcomes. Methodological quality and risk of bias were assessed using the MINORS score. Due to substantial heterogeneity, results were synthesized descriptively. Results: Forty studies met the inclusion criteria, encompassing 5343 patients and 4638 surgically treated calcaneal fractures. Displaced intra-articular fractures predominated, with Sanders type II and III accounting for 79.8% of classified fractures, while Sanders type IV fractures represented 20.2% and were associated with higher complication rates. The overall post-operative infection rate was 9.4%, including 6.3% superficial surgical site infections and 3.0% deep infections. Open fractures accounted for 7.5% of reported cases and demonstrated markedly higher infection rates than closed injuries. Deep infections frequently required implant removal (62%), prolonged intravenous antibiotic therapy (100%), and additional surgical procedures (71%). Staphylococcus aureus, including methicillin-resistant strains, was the most commonly isolated pathogen. Functional outcomes were consistently worse in patients who developed infections. Conclusions: Infectious complications remain a clinically significant problem following surgical treatment of calcaneal fractures, particularly in severe fracture patterns, open injuries, and patients with relevant comorbidities. Deep infections are associated with substantial morbidity and inferior functional outcomes. Optimization of patient-related risk factors, careful surgical planning, and the selective use of minimally invasive approaches may help reduce infection risk. Further high-quality prospective studies with standardized outcome measures are needed to define optimal management strategies. Full article

With the expansion of global oil and gas resource exploration and development into deep and ultra deep layers, the efficient development of deep carbonate rock fracture cave reservoirs has become the key to ensuring energy security. However, this type of reservoir commonly faces high temperatures, high salinity, and extremely strong heterogeneity, leading to increasingly severe water content spikes caused by dominant water flow channels. Although the existing traditional inorganic plugging agent has good temperature resistance, it has the defects of great brittleness and easy cracking, while the organic polymer gel is prone to degradation failure under high temperature and high salt environments. In order to solve the above problems, a new biochar-enhanced inorganic composite gel system was constructed by using biochar prepared from agricultural and forestry waste pyrolysis as a functional enhancement component. Through rheological testing, high-temperature and high-pressure mechanical experiments, long-term thermal stability evaluation, and dynamic sealing experiments of fractured rock cores, the reinforcement and toughening laws and rheological control mechanisms of biochar on inorganic matrices were systematically studied. Research has found that a biochar content of 0.5 wt% can significantly improve the micro pore structure of the matrix. By utilizing its micro aggregate filling effect and interfacial chemical bonding, the compressive strength of the solidified body can be increased to over 2 MPa, and there is no significant decline in strength after aging at 130 °C for 30 days. More importantly, the unique “adsorption slow-release” mechanism of biochar effectively stabilizes the hydration reaction kinetics at high temperatures, extending the solidification time of the system to 15 h and solving the problem of flash condensation in deep well pumping. This system exhibits excellent shear thinning characteristics and crack sealing ability, and presents a unique “yield reconstruction” toughness sealing feature. This study elucidates the multidimensional strengthening mechanism of biochar in inorganic cementitious materials, providing technical reference for stable oil and water control in deep fractured reservoirs. Full article

Produced-water (PW) management in the Permian Basin faces tightening injection constraints, induced seismicity concerns, and volatile saltwater disposal (SWD) costs. At the same time, chemistry-rich PW contains dissolved constituents (e.g., Li, B, and Sr) that may be valorized if SWD recovery performance and market conditions support favorable techno-economics. Here, we develop an integrated decision-support framework that couples (i) chemistry-informed surrogate models for unit process performance (recovery, effluent quality, and energy/chemical intensity) with (ii) a network-based allocation model that routes PW from sources through pretreatment, optional treatment and mineral-recovery modules (e.g., desalination and direct lithium extraction), and end-use nodes (beneficial reuse, hydraulic fracturing reuse, mineral recovery/valorization, or Class II disposal). This is a screening-level demonstration using publicly available chemistry percentiles and representative pilot-reported performance windows; it is not a site-specific facility design or a bankable TEA for a particular operator. The optimization is posed as a tri-objective problem—to maximize expected net present value, minimize SWD, and minimize an injection-risk indicator R—subject to mass balance, capacity, quality, and regulatory constraints. Uncertainty in commodity prices, recovery fractions, and operating costs is propagated via Monte Carlo scenario sampling, yielding PARETO-efficient portfolios that quantify trade-offs between profitability and risk mitigation. Using the PW chemistry percentiles reported by the Texas Produced Water Consortium for the Delaware and Midland Basins, we derive screening-level break-even lithium concentrations and illustrate how lithium-carbonate-equivalent price and recovery govern the extent to which mineral revenue can offset SWD expenditures. Comparative brine benchmarks (Smackover Formation and Salton Sea geothermal systems) contextualize the Permian’s generally lower-Li PW and highlight transferability of the workflow across brine types. The proposed framework provides a transparent, extensible basis for design matrix planning under evolving injection limits, enabling risk-aware PW management strategies that reduce disposal dependence while improving water resilience. Full article