Fatigue life prediction of steel components with local surface damage using ultrasonic imaging and critical distance theory.

Quantitative assessment of notch fatigue behavior in Mg-RE alloys via zero-point critical distance theory

Notch and size effects significantly influence the fatigue performance of engineering components, which is crucial for ensuring structural integrity. A novel probabilistic fatigue life prediction Kt-V-L model considering both the size and the notch effect, based on the theory of critical distance L (TCD) and the improved highly stressed volume V (HSV) method, is proposed in this study. The new definition more accurately characterizes fatigue damage and accumulation, overcoming the underestimation issues of traditional HSV methods under high-stress or low cycle fatigue (LCF) conditions. Specifically, the Weibull distribution is also proposed to characterize the material fatigue failure probability. The experimental data of 26Cr2Ni4MoV, En3B, and TC4 materials with varying notched sizes are utilized for the model validation and comparison. In addition, the predictive ability of the point method (Kt-V-L-PM) and line method (Kt-V-L-LM) under the novel proposed model was explored and evaluated. The predicted lives of 26Cr2Ni4MoV specimens fall within the ±2 scatter band of the Kt-V-L-LM, while the Kt-V-L-PM shows increasing deviation with larger notches due to its limited ability to capture stress gradients. For En3B and TC4, the predicted lives are within ± 2 life factors, verifying the model’s reliability and accuracy. Furthermore, fracture morphology analysis reveals the influence of notches on fatigue performance and elucidates the fracture failure mechanisms.

This article offers a linguistic analysis of Sandra Silberstein’s War of Words: Language, Politics and 9/11 (2002) through the lens of discourse theory, metaphor and other literary devices analysis. It argues that the political rhetoric following 9/11 transformed language into a literary system of myth-making, metaphor, and narrative framing. From the Kosovo-Albanian scholarly perspective, grounded in the recognition of the United States as a principal supporter of Kosovo’s independence and a decisive actor in the cessation of the conflict through its political and military interventions, the primary aim is to conduct a nuanced analysis of the metaphors embedded in post-crisis language. This analysis is undertaken with both cultural affinity and critical analytical distance, refraining from judgment or normative critique, and focusing instead on how such metaphors operate as both articulations of trauma and as frameworks for collective memory and sociopolitical action. Using Critical Discourse Analysis and Cognitive Metaphor Theory, the study investigates how Silberstein conceptualizes language as a semiotic resource that constructs and negotiates national identity and rationalizes foreign policy through metaphorical mappings and discourse structuring mechanisms and the way it resonates with the post-war situation in Kosovo.

When forming a platoon, trucks equipped with connectivity and autonomous driving capabilities can reduce the fuel consumption of the following trucks while minimizing road space usage. This improves transportation efficiency, conserves energy, and lowers the risk of traffic accidents. Beyond fuel consumption, time cost is a crucial factor in freight transportation and significantly influences platooning strategies. This paper focuses on trucks operating on freeways and develops separate models for fuel consumption and time costs based on truck dynamics and transport economics. A comprehensive cost function integrates these models to construct a truck platooning spatial domain model. To solve this model, we introduce a platooning spatial domain model using the platooning discriminant coefficient, enabling the calculation of the critical distance threshold between trucks and suitable platoons. Additionally, we propose the concept of platooning incentive factors to quantify the benefits of platooning driving compared with individual driving. Furthermore, we provide a decision-making basis when multiple platoons are available. A case study on the route from Changchun to Shenyang in China investigates the effects of four key parameters on the critical platooning threshold and its benefits: 1) initial speed when deciding to join, 2) truck catch-up speed, 3) platoon speed, and 4) variation in air drag within the platoon. Results demonstrate that, within a speed range of 80–100 km/h, the platooning discriminant coefficient consistently remains greater than 0, meaning trucks benefit by joining the platoon within the critical threshold of the spatial domain. Furthermore, the platooning incentive factor exhibits an inverse relationship with the distance between trucks and platoons. Therefore, when it can join multiple platoons, a truck should join the nearest platoon for maximum platooning benefits.

PurposeTo evaluate the clinical performance of a novel multifocal toric contact lens design combining a pupil-optimized multifocal design with a blink stabilized toric design featuring a single cylinder power and a choice of 3 add powers in a group of presbyopic patients with low to moderate astigmatism.Patients and MethodsA total of 171 subjects (105 myopic and 66 hyperopic) with refractive astigmatism of −1.00 diopter (D) to −1.75D with axes 90±15 or 180±15 degrees were fit with the study lenses in a two-week, multi-site prospective open-label clinical trial. The test lens was a multifocal toric soft contact lens with sphere powers of −1.00D to −4.00D and +1.00D to +4.50D, and a single cylinder power of −1.00D with axes 90±10 and 180±10 degrees. Outcome measures included logMAR Visual Acuity, subjective assessments of vision, comfort and handling, and fit metrics including orientation, rotational stability and fit success.ResultsOver 96% of subjects were fit in the optimized lens power with 2 pairs of lenses or less. After 2-weeks of lens wear, the mean binocular high luminance high contrast (HLHC) logMAR visual acuities were −0.085, −0.023, and 0.083, for distance (4m), intermediate (64cm), and near (40cm), respectively. Subjective vision, comfort and handling scores established statistically higher scores for both hyperopes and myopes compared to the pre-defined margin. The percentage of eyes with absolute lens orientation error ≤10° was over 94% and rotational stability ≤5° was over 98%.ConclusionThe multifocal toric contact lens design provided clear and consistent vision for a variety of critical distance, intermediate and near tasks across varying lighting conditions and had a high rate of lens fit success.

Abstract Elastic interaction of pressurized spherical cavities embedded in a three-dimensional hyperelastic medium is computationally analyzed. Using finite element analysis across several positive and negative pressure scenarios, we calculate the system’s potential energy and configurational driving force for neo-Hookean, Mooney–Rivlin, and Arruda–Boyce material models. Our results show that while the interaction is always attractive for negative pressures, a nonmonotonic energy landscape emerges for positive pressures above a critical value. In this regime, cavities attract at close range and repel when further apart. The critical separation distance for this transition is shown to be dependent on the material’s strain-stiffening parameters. These findings are consolidated into phase diagrams, providing a clear map of interaction behaviors.

Judd-Ofelt analysis and photoluminescence behavior of Tb3+-activated K7SrY2(B5O10)3 phosphors modified with alkali co-dopants for solid-state lighting applications.

Abstract Nanoscale gouge particles are common products during both rock friction experiments and natural fault slip. However, the frictional wear mechanisms of nanoscale gouge particles and their role in the evolution of fault shear strength remain poorly understood. Therefore, we employed the molecular dynamics method to simulate a series of nanoscale single‐particle wear processes in α ‐quartz sandwiched by two rough surfaces composed of spherical asperities. We explored the effects of asperity interval, particle size, contact configuration and the normal force on the wear damage and wear volume of gouge particles, as well as the influence of particle wear damage mode on the friction coefficient. We observed that higher normal forces could induce particle breakage over shorter loading distances, and the particles underwent three wear stages: stable, sub‐stable, and fracture stages. At stable stage, the wear volume increased linearly with loading distance. Sub‐stable stage was characterized by superliner wear volume growth. The wear volume in both stable and sub‐stable wear stages could be predicted by tangential shear work, as the shear work scaled well with the wear volume. Finally, we measured the critical loading distance until particle fracture. The particle size, normal force and contact configuration could significantly influence the lifetime of α ‐quartz gouge particles, and particle fracture could lead to an immediate increase in friction coefficient rather than a decrease. These findings could provide useful insights into the nanoscale friction and wear mechanisms of gouge particles, which will contribute to the understanding of the microscopic fault frictional behavior.

With the recent emergence of Generative Artificial Intelligence (Gen-AI) tools in the translation field, the longstanding notion that machines are limited to translating generic content has been overturned. There is considerable potential to explore the use of Gen-AI tools to translate literary and poetic texts, such as Cantonese opera libretti, which exhibit nuanced expression, rich poetic resonance, and cultural references rooted in traditional Chinese history and folk traditions, into English, with particular attention to satisfactorily translate linguistic intricacies and cultural depth. The successful translation of such texts typically demands bilingual fluency, bicultural awareness, and a high degree of sensitivity to cultural subtleties. The key task in this context is to investigate how human translators could be trained to navigate and post-edit AI-translated texts. It is recommended that translators learn to harness AI’s capabilities while maintaining a critical distance to ensure that the translated output is not overly dominated by certain stylistic tendencies. A partnership between AI and professional human translators could help preserve artistic integrity, deepen cultural insights, and enhance professional accuracy in the translation process. Such a partnership would not only yield more refined and cohesive translations but also increase the engagement of target audiences with the cultural allusions and subtexts embedded in the original scripts.

The demand for work safety protection in Human-Robot Interaction (HRI) work cells is rapidly increasing, driven by the projected 34.3% Compound Annual Growth Rate (CAGR) of the global Collaborative Robot (Cobot) market from 2020 to 2030 [1]. According to IRF-World Robotics 2023, it is reported that there are nearly 4 million industrial robots in operation worldwide, with approximately 10% of them being cobot [2]. A NIOSH report highlighted 61 robot-related fatalities between 1992 and 2015, with an expectation of further rising due to the increasing use of industrial robots and cobots in the US work environment [3]. A recent study in [4] delved into 355 robot accidents documented by KOSHA between 2009 and 2019, revealing that 95% occurred in manufacturing businesses. Pinch and crush incidents accounted for 52% of the accidents, while impacts and collisions accounted for 36%, and the remaining 12% involved falls, flying objects, trips/slips, cuts, burns, etc. These findings align with US data reported in [5].The rising integration of cobot units among major manufacturers emphasizes the critical need for enhancing cobot safety in manufacturing. Owing to safety considerations and regulatory requirements, existing cobots frequently operate at significantly reduced speeds and are restricted from undertaking complex interaction tasks in shared workspace. This limitation has curtailed the full potential utilization and productivity of cobots in manufacturing. This paper introduces a novel 3D sensing framework designed to address these limitations by enabling safety assurance in workspaces requiring close human-robot interaction. The framework generates 3D human pose information and relays it to the robot for real-time safety monitoring. Our methodology begins with data collection from a single RGB-D camera capturing human-robot interactions in a manufacturing environment. Human shape and pose are predicted using deep neural networks, which then incorporate depth information and undergo 3D geometric transformations to deduce size, shape, and translation. This process produces a reconstructed 3D avatar with pose, size, and location. Following 3D human posture estimation, this data is then integrated into a virtual environment with a real robot for real-time monitoring. Results demonstrate successful reconstruction of 3D human geometry within human-robot collaboration settings. By integrating both the reconstructed mesh and real-time robot state into a unified virtual environment, we achieved real-time, offline, continuous monitoring of the critical distance between robot and human throughout operation. These distance measurements provide crucial data for developing collision detection, prediction, and avoidance capabilities when incorporated into the robot control feedback loop.

In devices based on two-dimensional electron gases (2DEGs), gate electrodes can be used to tune the electronic properties by controlling the electron density. Despite the prevalence of such gated systems, the properties of 2DEGs in these environments remain poorly understood quantitatively. To address this, we have studied the 2DEG in a dual-gate geometry using quantum MonteCarlo simulations alongside simpler approximate methods, and we have mapped out the phase diagram of the gated 2DEG as a function of electron density and gate distance. We find that the Wigner crystal is unstable at all densities when the gates are sufficiently close to the 2DEG, and we identify the critical gate distance at which the Wigner crystal phase appears. For larger gate separations, we determine the phase boundary for the reentrant crystal to liquid transition that occurs with decreasing density. Our Letter is particularly relevant to Wigner crystal phases recently observed in a variety of gated two-dimensional materials.

Abstract Laser -hybrid welded butt joints are increasingly used in structural applications due to their high productivity. However, the complex interaction between the laser beam and arc process often leads to weld imperfections. These weld imperfections can significantly influence the development of stress concentrations on the weld surface, which can affect the mechanical properties and fatigue performance of the joints. Therefore, accurately identifying and assessing these imperfections is crucial for ensuring weld quality and structural safety. In this study, a method is proposed to assess the weld quality and numerically determine stress concentrations in laser-hybrid welded butt joints with severe imperfections using 3D scans. For this purpose, a total of 76 specimens were scanned using a high-resolution 3D laser scanner to capture the weld geometry. The scan results were then used to assess the weld quality according to the ISO 12932 standard and to generate numerical models by using the reverse engineering method for 3D finite element (FE) analysis. Additionally, fatigue tests were performed to observe the failure location for each specimen and compare it with the predicted failure location from the FE analysis. While the FE predictions could effectively highlight the critical high-stress regions, they did not consistently match the actual crack initiation sites due to the complexity and variability of weld imperfections. However, considering the micro-support effect through the theory of critical distances improved the accuracy of failure location and fatigue life predictions by accounting for the influence of local stress gradients.

ObjectivesIatrogenic injury to the circumflex artery (CX) during mitral valve (MV) surgery occurs in 0.3%-1.8% of cases. This study analysed the CX’s anatomical relationship to the mitral annulus using advanced imaging to predict peri-operative risk in patients undergoing endoscopic MV surgery.MethodsA CT analysis using 3mensio software was performed in 315 patients (2019-2023) undergoing minimally invasive MV surgery. A prediction index (PI) for CX injury was calculated to identify at-risk individuals.ResultsCX anatomy was assessable in all patients (n = 315). The mean age was 62.84 ± 11.34 years; median annulus area was 12.97 ± 5.69 cm2. The mean distance between the left CX and mitral annulus was 6.97 ± 3.85 mm. A critical distance <4 mm was observed in 23.5% (74/315), among whom circumflex obstruction occurred in 2.71% (2/74), compared to 0% in those with ≥4 mm distance (P = .05). Percutaneous coronary intervention was required in 0.32% (1/315). A low injury PI (≤0.2) was found in 27.31% (86/315), correlating with male sex, larger annular dimensions, and elevated injury risk.ConclusionsPreoperative CT-based measurement of the CX’s distance from the mitral annulus is feasible and may identify patients at elevated risk for iatrogenic injury. A distance ≤4 mm or injury PI ≤0.2 indicates increased risk. Routine CT imaging, combined with coronary angiography, is recommended for risk stratification before MV surgery.

Abstract The article critically examines how a comparatist’s positionality and purpose shape the design and outcomes of comparative legal research. Amid ongoing debates in comparative law – pitting functionalist against cultural approaches, or sameness-seeking projects against difference-embracing ones – this article shifts the focus toward a more foundational concern: the motivations behind comparison and the discursive contexts in which it occurs. While questions of “how to compare” dominate methodological discourse, this article insists that we must first confront “why we compare” and “to whom we are speaking.” These inquiries are not peripheral but central to the integrity and potential of comparative legal scholarship. The article argues that every comparatist operates from a particular legal and cultural position, and with a specific communicative aim: their positioned purpose. This purpose not only motivates the comparative endeavor but also determines how domestic and foreign legal systems are selected, interpreted, and related to each other. By ignoring their own motivations and situated perspectives, comparatists risk designing methods that are ill-suited to their actual goals and miss out on the critical potential that comparison uniquely offers. In reclaiming a central insight of critical comparative scholarship, the article rejects the illusion of methodological neutrality or objectivity. However, it also challenges some prevailing assumptions within the critical camp, particularly the tendency to conflate the positionality problem solely with ethnocentrism, and to treat a turn to cultural difference as an automatic corrective. Positionality manifests in more nuanced and varied ways, depending on whether one is speaking from or to the Global North or Global South, for example. The same methodological risks (ethnocentrism and status quo bias) play out differently across contexts, making positionality a dynamic rather than monolithic concern. The article is structured in three parts. Part 1 introduces the problem of positionality and explores how its neglect leads to recurring fallacies in comparative research. Part 2 presents the idea of comparative projects as purposeful constructions, shaped by the comparatist’s discursive and institutional location. Part 3 examines how the specific contours of ethnocentrism and status quo bias vary with the comparatist’s positioned purpose, demonstrating why there can be no universal fix or one-size-fits-all critique for methodological flaws in comparative law. Ultimately, the article argues that positionality should be neither denied nor lamented, but embraced as a source of methodological strength. Comparative law, because of its relational nature and critical distance from doctrinal orthodoxy, is especially well suited to turn positionality into a productive resource. Rather than impeding meaningful comparison, a reflexive understanding of one’s position and purpose enables more contextually attuned, critically engaged, and methodologically sound comparative work.

Shockwaves from air bubbles within pits induced by nearby cavitation bubbles

The article is devoted to the life and scientific views of the Polish historian of Russian philosophical and social thought Andrzej Walicki. It describes the conditions for the for­mation of the philosopher’s views, examines the reasons why, despite the widespread negative attitude towards Russia in Poland, he developed a fairly objective view of Rus­sian history and philosophy. In this regard, the article refers to a number of significant facts of Valicky’s intellectual biography. The personal motivation of his position is shown, which partly comes from his family and largely from family friends. The author, in particular, draws special attention to the fact that Valicky sincerely confessed a kind of intellectual attachment to Russia. It is noted that in his writings the Polish historian of Russian thought raises fundamental questions concerning its place in the general process of development of European philosophy. However, as shown in the article, the Polish scientist managed to maintain objective restraint and critical distance. In his re­search, he was guided by the Spinoza principle of “not to ridicule, not to be upset, not to curse, but to understand.” The article examines the features of the methodology of A. Valicky, based on the sociological ideas of K. Mannheim. The generally justified nature of the conclusion of the Polish thinker about the belonging of Russian philosophy to the intellectual space of Europe is emphasized, which (conclusion) is combined with the recognition of a certain originality of Russian philosophical thought arising from the conditions of its development and national specifics. The author of the article considers the priority of Russian thinkers noted by A. Valitsky in distinguishing between different types of sociality, which anticipated the distinction introduced by Tönnis between Ge­meinschaft and Gesellschaft. At the same time, the author of the article expresses his dis­agreement with Valitsky’s thesis, which states that the philosophical position of the Sla­vophiles was only a kind of pan-European conservative romanticism of the 19th century and draws attention to its relevance in modern intellectual discussions.

ABSTRACT Conducting voice research in non-acoustically optimized spaces, such as clinics or classrooms, presents significant challenges. These environments introduce acoustic variables that can distort the accurate representation of the sound source. To ensure recordings faithfully reflect the original voice, it is crucial to implement standardized procedures, select appropriate equipment, and understand the acoustics of the recording space. The literature identifies three key parameters for guaranteeing the reliability of voice recordings: background noise level, reverberation, and critical distance. However, detailed methods for assessing these parameters are often lacking or scattered across various sources. This study draws on standards from the International Electrotechnical Commission (IEC), the International Organization for Standardization (ISO), and published acoustic protocols to offer a practical guide for measuring the acoustic suitability of non-treated recording spaces. It provides step-by-step procedures, equipment recommendations, and guidance on analysis software to assess the three parameters. A case study is used to illustrate best practices for data presentation and interpretation. This article offers a comprehensive and cost-effective framework to assess acoustic conditions in everyday voice research settings. It supports researchers working in untreated spaces and promotes methodological rigor despite the limitations of real-world environments, encouraging high-quality data collection where acoustically treated rooms are not available.

The presence of sound in cinema shares and assumes entirely the narrative power typically associated with visual imagery. A sound-based cinematic aesthetic not only shapes the viewer’s perception but also enhances the emotional and conceptual depth of the narrative. The delicate aesthetic balance of sound design plays a crucial role in shaping storytelling, as cinema draws upon both visual and auditory elements in harmony, often referencing real-life experiences. This study offers an original analysis of the aesthetic use of sound in cinema through the lens of Bertolt Brecht’s theory of alienation, focusing specifically on film Memoria (2021), directed by Apichatpong Weerasethakul. Memoria becomes the subject of this inquiry due to its unique sound design, which leads the audience and its protagonist on a journey through abstract concepts such as identity, space, and memory, guided by an undefined sound. Brecht’s alienation effect, originally developed for the theatre, lends itself to reinterpretation within multilayered narrative forms like cinema, where visual design and sound aesthetics can together foster critical distance. Brecht’s alienation theory promotes a theatrical aesthetic in which the audience remains detached from the dramatic flow, maintaining a reflective and critical stance toward the narrative an approach that also translates meaningfully to the cinematic medium. Weerasethakul’s Memoria, with its unconventional use of sound, constructs a cinematic atmosphere that not only tells a story but also challenges the perception of time, memory, and space anchoring these themes deeply in a quasi-realist framework. Simultaneously, this study investigates how Brecht’s alienation theory can provoke critical engagement with fictional worlds through sound, by exploring the phenomenon of estrangement using Michel Chion’s key concepts: acousmêtre, anempathetic sound, sound bridge, and vococentrism. These theoretical tools enable a deeper reflection on how sound in cinema may disrupt narrative realism and generate estrangement in the audience. Thus, while analyzing the film's distinct sonic narrative, this study assumes that these concepts will also illuminate and enrich the broader discussion.

ABSTRACTIn response to the issue that existing deep soft high‐gas coal seam floor blasting permeability enhancement techniques neglect the influence of in situ stress, a bidirectional loading gas‐solid coupling blasting simulation system was established in the laboratory to achieve multidimensional damage characterization. Comparative simulation experiments were conducted under different burial depths. The results indicate that in situ stress significantly inhibits the propagation of blasting‐induced cracks, with the inhibitory effect intensifying with increasing in situ stress levels. As the burial depth H increases from 0 to 1000 m, the damage reduction in the S3 profile of the coal mass at the distal end of the test block becomes more pronounced, demonstrating that in situ stress exerts a stronger inhibitory effect on crack propagation in low‐strength media at greater distances. In situ stress attenuates the propagation intensity of blasting stress waves, with low‐strength media showing greater sensitivity to the attenuation effect of blasting waves under in situ stress. Numerical simulations using ANSYS/LS‐DYNA software revealed that the damage induced by floor blasting is primarily concentrated at the interface between the floor and coal‐rock, with in situ stress limiting the extent of the crack zone while having minimal impact on the crushed zone. A predictive model based on fractal dimension D and damage quantity w was developed, effectively assessing the degree of blasting damage in coal and rock under different in situ stress conditions. The influence of in situ stress on blasting stress wave propagation exhibits a critical distance. These research findings provide valuable insights for the safe and efficient extraction of deep, soft, high‐gas coal seams.