Search Results (3,305)

Achieving keyhole-free joints is critical in Friction Stir Spot Welding (FSSW). This study presents a new approach to eliminate this volumetric defect in AA6082-T6 FSSW sheet joints using a continuous multi-layer Friction Stir Deposition (CMFSD) technique, employing a newly designed AA6082-T6 consumable tool. FSSW was performed at various rotational speeds (350, 550, 750 and 950 rpm) with a 5 s dwell time. Comprehensive macro- and micro-scale evaluations, along with mechanical properties (hardness and tensile-shear load) of the produced joints, were conducted. Additionally, microstructures were examined using Optical Microscopy (OM), while fracture surfaces were analyzed via Scanning Electron Microscopy (SEM). Optimal FSSW conditions were identified at 550 rpm, yielding a stir zone (SZ) hardness of 94.6 ± 1.4 HV and a maximum tensile-shear load of 4.73 ± 0.27 kN. The keyhole was successfully refilled using AA6082-T6 rod material via CMFSD, resulting in a defect-free joint of the same base alloy. Electron Backscattered Diffraction (EBSD) technique was also used to examine the microstructural features. A comparative analysis revealed significant enhancements: the refilled FSSW joints exhibited a 46.5% increase in maximum tensile-shear load and a 66.66% improvement in elongation to failure compared to the highest-FSSW joint performance with the keyhole defect. Full article

Existing CO₂ leakage risk assessment frameworks for CO₂ capture, geological storage and utilization (CCUS) projects face limitations due to subjective biases and poor adaptability to long-term scale sequestration. This study proposed a dynamic risk assessment method for CO₂ leakage based on a timeliness analysis of different leakage paths and accurate time-dependent numerical simulations, and it was applied to the first CO₂ enhanced gas recovery (CCUS-EGR) pilot project of China in the Maokou carbonate gas reservoir in the Wolonghe gas field. A 3D geological model of the Maokou gas reservoir was first developed and validated. The CO₂ leakage risk under different scenarios including wellbore failure, caprock fracturing, and new fracture activation were evaluated. The dynamic CO₂ leakage risk of the CCUS-EGR project was then quantified using the developed method and numerical simulations. The results revealed that the CO₂ leakage risk was observed to be the most pronounced when the caprock integrity was damaged by faults or geologic activities. This was followed by leakage caused by wellbore failures. However, fracture activation in the reservoir plays a neglected role in CO₂ leakage. The CO₂ leakage risk and critical risk factors dynamically change with time. In the short term (at 5 years), the project has a low risk of CO₂ leakage, and well stability and existing faults are the major risk factors. In the long term (at 30 years), special attention should be paid to the high permeable area due to its high CO₂ leakage risk. Factors affecting the spatial distribution of CO₂, such as the reservoir permeability and porosity, alternately dominate the leakage risk. This study established a method bridging gaps in the ability to accurately predict long-term CO₂ leakage risks and provides a valuable reference for the security implementation of other similar CCUS-EGR projects. Full article

Currently, there is a lack of methods for detecting the mechanism of gas explosion propagation within flameproof enclosures and the dynamic behavior of flameproof enclosures under explosion impact. Therefore, this paper studies a method for detecting the vibration characteristics of coal mine explosion-proof equipment under internal gas explosions using laser Doppler. First, a model of gas explosion propagation and explosion transmission response in flameproof enclosures is established to reveal the mechanism of gas explosion transmission inside coal mine flameproof enclosures. Second, a laser Doppler measurement method for coal mine flameproof enclosures is proposed, along with a step-by-step progressive vibration characteristic analysis method. This begins with a single-frequency dimension analysis using the Fourier transform (FFT), extends to time–frequency joint analysis using the short-time Fourier transform (STFT) to incorporate a time scale, and then advances to a three-dimensional linkage of scale, time, and frequency using the wavelet transform (DWT) to solve the limitation of the fixed window length of the STFT, thereby achieving a dynamic characterization of the detonation response characteristics. Finally, a non-symmetric Gaussian impact load inversion model is constructed to validate the overall scheme. The experimental results show that the FFT analysis identified a 2000 Hz main frequency, along with the global frequency components of the flameproof enclosure vibration signal, the STFT analysis revealed the dynamic evolution of the 2000 Hz main frequency and global frequency over time, and the wavelet transform achieved higher accuracy positioning of the frequency amplitude in the time domain, with better time resolution. Finally, the experimental platform showed an error of less than 5% compared with the actual measured impact load, and the error between the inverted impact load and the actual load was less than 15%. The experimental platform is feasible, and the inversion model has good accuracy. The laser Doppler measurement method has significant advantages over traditional coal mine flameproof equipment measurement and analysis methods and can provide further failure analysis and prevention, design optimization, and safety performance evaluation of flameproof enclosures in the future. Full article

Most of the failures during the actual operation of equipment are caused by improper human operation, tools, spare parts, and environmental factors. These faults are routine. Conventional faults have been validated during equipment development, testing, identification, and maintenance processes, with clear definitions and clear fault tree analysis (FTA) conclusions. Digital twins can offer rapid and interactive diagnostic capabilities for routine equipment failures. To enhance the efficiency of routine fault diagnosis and the interactive experience of the diagnosis process, this paper proposes a digital twin-based equipment routine fault diagnosis model. On this basis, considering the excellent interactivity of the Interactive Electronic Technical Manual (IETM), a conventional equipment fault diagnosis scheme based on twin data and IETM is designed. This scheme converts the equipment fault tree into an IETM fault data model (DM), which is structured and stored in a database to form a fault database. Using real-time twin data of equipment as input, the FTA method is adopted to perform step-by-step fault diagnosis and isolation guidance operation through the IETM process DM combined with fault, while providing maintenance operation guidance. When the real-time twin data of the equipment is not completely consistent with the fault information in the fault library, the case analysis method is used to calculate the similarity between the real-time twin data of the equipment and the clearly defined fault symptom information in the fault library. Based on the set similarity threshold, IETM pushes fault DMs above the threshold for corresponding fault diagnosis isolation guidance. Full article

Introduction: Tertiary hyperparathyroidism following kidney transplantation is a well-recognized complication in patients with pre-existing mineral imbalances due to chronic renal failure. Parathyroidectomy remains the only definitively curative option for tertiary hyperparathyroidism. The optimal timing of parathyroidectomy, before or after transplantation, is debated in the literature. This study aims to assess whether parathyroidectomy timing affects the successful resolution of tertiary hyperparathyroidism in patients with a functional kidney transplant. Methods: We conducted a systematic review and meta-analysis of the available literature collating the effect of pre- versus post-transplantation parathyroidectomy on the resolution of tertiary hyperparathyroidism. We compared the follow-up parathyroid hormone and calcium levels of patients subjected to either of these two approaches. Results: Three studies were identified, encompassing a total of 223 patients. The meta-analysis of available data yielded no statistically significant difference between pre- and post-kidney transplantation parathyroidectomy in terms of serum parathyroid hormone (SMD −0.19, 95% CI −0.92 to 0.55, p = 0.62) and calcium levels (SMD −0.75, 95% CI −2.30 to 0.80, p = 0.35). Conclusions: We demonstrated no significant difference between pre- and post-transplantation parathyroidectomy when it comes to the treatment of tertiary hyperparathyroidism. This meta-analysis is limited by the small number of studies included, reducing its statistical power. Therefore, additional studies are required to identify the optimal timing of intervention for the effective management of tertiary hyperparathyroidism in kidney transplant recipients. Full article

The coupled factors of high temperature, high humidity, and high salinity in tropical marine atmospheres severely threaten the long-term service performance of power transmission and transformation infrastructure. This paper establishes an accelerated cyclic testing protocol (salt spray → drying → damp heat → drying) to evaluate performance and elucidate the dynamic corrosion failure mechanisms of the organic Zn14Al1.4 composite coating. By integrating multiphysical characterization techniques (SEM, EDS, XPS) with electrochemical analysis, this study for the first time elucidates the dynamic transformation of corrosion products: initially dominated by Zn(OH)₂, progressing to complex passive phases such as Zn₅(OH)₈Cl₂·H₂O, Zn₅(OH)₆(CO₃)₂, and Zn₆Al₂(OH)₁₆CO₃ in the mid-term, and ultimately dominated by Fe-based products (FeO, Fe₂O₃, Fe₃O₄, FeOOH) that drive interfacial failure. And a four-stage corrosion evolution model was defined: incubation period, accelerated degradation phase, substrate nucleation stage, and catastrophic failure phase. The investigation reveals a shift in the coating/substrate interface failure mechanism from purely physical barrier effects to electrochemical synergy, providing a theoretical framework for the optimized design and service-life prediction of anticorrosive coatings for transmission and transformation equipment in tropical environments. Full article

Background: Multi-organ failure (MOF) is a common complication of advanced heart failure (HF), significantly influencing patient prognosis. This study aimed to assess and compare the impact of orthotopic heart transplantation (HTx) and left ventricular assist device (LVAD) implantation on the severity of MOF, as measured by the model for end-stage liver disease excluding INR (MELD-XI) score. Methods: Data from 1 month before to 1 year after HTx or LVAD implantation were analysed. The MELD-XI score was calculated using average bilirubin and creatinine values. Comparative assessments of MELD-XI scores were performed within the HTx and LVAD groups at various time points pre- and post-procedure. Results: The analysis included 107 HTx patients and 30 LVAD patients. The median MELD-XI score 1 month pre-procedure was 11.7 (9.4–16.7) in all patients. There were no significant differences in MELD-XI scores between the groups at 3-, 6-, and 12-month follow-ups. However, a significant difference was observed 1 month post-procedure [HTx: 14.8 (9.4–17.7) vs. LVAD: 11.2 (7.3–14.9), p = 0.02]. In the LVAD group, a significant decrease in MELD-XI score was noted for 3 months post-procedure compared to 1 month pre-procedure (p < 0.001), whereas at 6- and 12-month follow-ups the score did not differ from pre-procedural scores. In the HTx group, significant decreases in MELD-XI scores were observed from 3 months, 6 months, and 1 year post-procedure compared to 1 month pre-procedure (p < 0.002). Conclusions: The MELD-XI scale reveals different MOF trajectories between HTx and LVAD recipients. Both interventions lead to early improvements in liver and kidney function, with sustained benefits in HTx patients, highlighting the distinct impacts on organ function. Full article

This review investigates how process parameters and material choices influence the mechanical performance of parts produced by material extrusion additive manufacturing, with a particular focus on Material Extrusion (ME). Through a systematic bibliometric analysis of literature between 2015 and 2025, the study identifies key factors affecting mechanical strength, anisotropy, and structural reliability, including printing temperature, speed, orientation, layer thickness, and interlayer bonding. Emphasis is placed on emerging techniques such as 4D printing, fiber-reinforced composites, and novel monitoring methods like real-time vibration sensing and thermal imaging, which offer promising pathways to improve part performance and process stability. Three research questions guide the analysis: (1) how printing parameters affect micro- to macrostructure and failure behavior, (2) how optimization strategies enhance part quality, and (3) how material and process selection aligns with functional requirements. The review highlights both advances and persistent limitations in process control, material compatibility, and anisotropic strength. It concludes with a call for further integration of predictive modeling, hybrid material systems, and closed-loop process monitoring to unlock the full potential of additive manufacturing in high-performance engineering applications. Full article

For reliable electronics, it is important to have an understanding of solder joint failure mechanisms. However, because of difficulties in real-time atomistic scale analysis during deformation, we still do not fully understand these mechanisms. Here, we report on the development of an innovative in situ method of observing the response of the microstructure to tensile strain at room temperature using high-voltage transmission electron microscopy (HV-TEM). This technique was used to observe events including dislocation formation and movement, grain boundary formation and separation, and crack initiation and propagation in a Sn-3 wt.%Ag-0.5 wt.%Cu (SAC305) alloy joint formed between copper substrates. Full article

Amyotrophic lateral sclerosis (ALS) is still a heterogeneous neurodegenerative disorder that can be identified clinically and biologically, without a strong set of biomarkers that can adequately measure its fast rate of progression and molecular heterogeneity. In this review, we intend to consolidate the most relevant and timely advances in ALS biomarker discovery, in order to begin to bring molecular, imaging, genetic, and digital areas together for potential integration into a precision medicine approach to ALS. Our goal is to begin to display how several biomarkers in development (e.g., neurofilament light chain (NfL), phosphorylated neurofilament heavy chain (pNfH), TDP-43 aggregates, mitochondrial stress markers, inflammatory markers, etc.) are changing our understanding of ALS and ALS dynamics. We will attempt to provide a framework for thinking about biomarkers in a systematic way where our candidates are not signals alone but part of a tethered pathophysiological cascade. We are particularly interested in the fast progressor phenotype, a devastating and under-characterized subset of ALS due to a rapid axonal degeneration, early respiratory failure, and very short life span. We will try to highlight the salient molecular features of this ALS subtype, including SOD1 A5V toxicity, C9orf72 repeats, FUS variants, mitochondrial collapse, and impaired autophagy mechanisms, and relate these features to measurable blood and CSF (biomarkers) and imaging platforms. We will elaborate on several interesting tools, for example, single-cell transcriptomics, CSF exosomal cargo analysis, MRI techniques, and wearable sensor outputs that are developing into high-resolution windows of disease progression and onset. Instead of providing a static catalog, we plan on providing a conceptual roadmap to integrate biomarker panels that will allow for earlier diagnosis, real-time disease monitoring, and adaptive therapeutic trial design. We hope this synthesis will make a meaningful contribution to the shift from observational neurology to proactive biologically informed clinical care in ALS. Although there are still considerable obstacles to overcome, the intersection of a precise molecular or genetic association approach, digital phenotyping, and systems-level understandings may ultimately redefine how we monitor, care for, and treat this challenging neurodegenerative disease. Full article

This paper investigates the utilization of artificial neural networks (ANNs) for the proactive identification of gearbox failures in wind turbines, boosting the use of operational SCADA data for predictive analysis. Avoiding gearbox failures, which can strongly impact the functioning of wind turbines, is crucial for ensuring high reliability and efficiency within wind farms. Early detection can be achieved though the development of a normal behavior model based on ANNs, which are trained with data from healthy conditions derived from selected SCADA variables that are closely associated with gearbox operations. The objective of this model is to forecast deviations in the gear bearing temperature, which serve as an early warning alert for potential failures. The research employs extensive SCADA data collected from January 2018 to February 2022 from a wind farm with multiple turbines. The study guarantees the robustness of the model through a thorough data cleaning process, normalization, and splitting into training, validation, and testing sets. The findings reveal that the model is able to effectively identify anomalies in gear bearing temperatures several months prior to failure, outperforming simple data processing methods, thereby offering a significant lead time for maintenance actions. This early detection capability is highlighted by a case study involving a gearbox failure in one of the turbines, where the proposed ANN model detected the issue months ahead of the actual failure. The present paper is an extended version of the work presented at the 5th International Conference of IFToMM ITALY 2024. Full article

This study investigates the mechanical performance and failure mechanisms of large-span, cast-in situ hollow-core floor slabs with square-box core molds under vertical loading. A combination of in situ tests and refined numerical simulations was used to investigate the slab’s behavior. An 8 m × 8 m hollow slab from the Xinluzhou Industrial Park in Hefei, China, was subjected to five-stage cyclic loading up to 9.0 kN/m² using a distributed water tank system. Real-time strain monitoring showed that the slab remained within the elastic range, exhibiting a linear strain-load relationship and bidirectional bending stiffness, with less than 5% deviation between the X and Y directions. Finite element analysis, incorporating a concrete plastic damage model and a bilinear steel model, replicated the experimental stress distribution, with errors of less than 6.9% for reinforcement and 8.8% for concrete. The simulation predicted an ultimate load-bearing capacity of 27.2 kN/m², with initial failure indicated by diagonal cracks at the column capital edges, followed by flexural cracks at the slab mid-span. These findings clarify the bidirectional bending behavior and stress redistribution, characterized by “banded gradient” and “island-shaped” stress zones. This study provides valuable insights and design optimization strategies to improve the structural performance and safety of hollow-core floor slabs in high-rise buildings. Full article

Butyric acid is one of the main volatile fatty acids (VFAs) in Maotai-flavor liquor wastewater (MFLW), and its degradation process exhibits a positive Gibbs free energy, making it prone to accumulation during high-load anaerobic digestion (AD), which can lead to system instability or even failure. In this study, hydrochar (HTC) was prepared from rice husk obtained from distiller’s grains, and butyrate-degrading microbiomes were selectively enriched under acidic conditions with butyric acid as the sole carbon source. Through co-incubation, the butyrate-degrading microbiomes were successfully pre-coupled with HTC, forming a “hydrochar–microbe” composite, which was then applied to the AD of MFLW. The experimental results demonstrated that this composite enhanced system performance. The hydrochar–butyrate pre-coupling group (HBA-C) showed a 15.48% increase in methane yield compared to the control group (CK), with a soluble chemical oxygen demand (sCOD) removal rate of 75.02%, effectively mitigating VFA accumulation. Microbial community analysis indicated higher bacterial and archaeal diversity indices in the HBA-C group. qPCR results showed that the bacterial and archaeal copy numbers in the HBA-C group were 22.06-times and 13.80-times higher than those in the CK group, respectively. Moreover, the relative abundance of the genes for the key enzymes methylmalonyl-CoA carboxyltransferase (EC: 2.1.3.1) and succinate dehydrogenase (EC: 1.3.5.1) was significantly increased, indicating that the “hydrochar–microbe” coupling enhanced carbon flow distribution efficiency and energy metabolism by optimizing metabolic pathways. This study provides an innovative strategy for MFLW treatment and offers practical value for anaerobic digestion optimization and high-strength wastewater management. Full article

Standard Operating Procedures (SOPs) serve a critical role in complex systems operations, guiding operator response during normal and emergency scenarios. This study compares 29 SOPs (517 steps) across three domains with varying operator selection rigor: airline operations, Habitable Airlock (HAL) operations, and semi-autonomous vehicles. Using the extended Procedure Representation Language (e-PRL) framework, each step was decomposed into perceptual, cognitive, and motor components, enabling quantitative analysis of step types, memory demands, and training requirements. Monte Carlo simulations compared Time on Procedure against the Allowable Operational Time Window to predict failure rates. The analysis revealed three universal vulnerabilities: verification steps missing following waiting requirements (70% in airline operations, 58% in HAL operations, and 25% in autonomous vehicle procedures), ambiguous perceptual cues (15–48% of steps), and excessive memory demands (highest in HAL procedures at 71% average recall score). Procedure failure probabilities varied significantly (5.72% to 63.47% across domains), with autonomous vehicle procedures showing the greatest variability despite minimal operator selection. Counterintuitively, Habitable Airlock procedures requiring the most selective operators had the highest memory demands, suggesting that rigorous operator selection may compensate for procedure design deficiencies. These findings establish that procedure design approaches vary by domain based on assumptions about operator capabilities rather than universal human factors principles. Full article

Sports teams increasingly use nostalgia-based marketing to spark fan engagement and boost merchandise sales. Yet these efforts can also provoke backlash, especially when they resurrect contested imagery. This article examines how one such campaign—the New York Islanders’ 2015 revival of their controversial fisherman logo—was framed across team broadcasts and interpreted by fans on social media. Drawing on a qualitative textual analysis of television and radio coverage alongside a quantitative content analysis of 563 tweets, the study reveals a divide between institutional messaging and grassroots reaction. While team broadcasts emphasized charity and sentimental appeal, fan discourse was notably more critical, mocking the jersey’s design and recalling past failures. By positioning nostalgia not only as a branding asset but as a reputational risk, the article contributes a novel perspective to debates about commercialization, mediatization, and fan co-production in sports. It also demonstrates the value of mixed methods for analyzing how branding narratives are negotiated in real time. Full article