Search Results (307)

Based on experimental studies, a model of the control effect on the plastic deformation process under boundary asymmetric loading conditions has been developed. The regulating factor of plastic deformation unevenness δ, which determines the stress–strain state of the entire deformation zone and the boundary conditions, is presented. The boundary conditions, determined by additional compressive and tensile stresses along the height, generate shear stresses and specific loading regimes at the edges and within the deformation zone itself. The confirmed reduction in interaction, which coincides with the effect of plastic deformation occurring under conditions of force unevenness, is one of the criteria for the controlling effect. A distinctive feature of this approach is the recognition and proof of the existence of a controlling additional effect under conditions of complex force and deformation loading. Theoretical and experimental studies have revealed such effects under various loading conditions. Based on a closed-form problem in plasticity theory and the method of argument functions of a complex variable, a mathematical model of the control process exerted by the metal’s plastic flow zone has been developed. A key feature of the solution to this theoretical problem was the consideration of the interaction between zones under different force loads, represented by a finite-difference scheme in the mathematical model. The decisive influence of deformation unevenness from the working rolls on the force and deformation parameters of the process was demonstrated, with the deformation unevenness factor δ serving as a quantitative measure of this influence. The result obtained through theoretical justification was confirmed by numerical simulation and a comparison of calculated data with experimental data, ensuring the reliability of the result. Full article

This paper develops a unified Lorentzian framework for persistent rigid motions generated by slant helices in three-dimensional Minkowski space and investigates their geometric and kinematic properties. Persistence is characterized by the constancy of the pitch of the instantaneous twist associated with a one-parameter rigid motion in the Poincaré group $\mathrm{ISO}(2,1)$. Interpreting curves in the motion group as trajectories of rigid motions, we study Frenet–Serret and adapted frame motions determined by slant helices under different causal characters. Necessary and sufficient conditions are established for these frame motions to generate persistent Lorentzian motions. An explicit intrinsic relationship between the pitches of Frenet–Serret and adapted frame motions is obtained in terms of the geodesic curvature of the spherical image of the principal normal indicatrix, showing that persistence is governed by intrinsic curve invariants and is independent of the chosen moving frame. The geometric structure of persistent motions is further clarified through associated ruled surfaces. In particular, the pitch of a persistent motion is shown to coincide with the distribution parameter of the ruled surface associated with the corresponding frame motion. Illustrative examples are presented for different causal configurations. These results extend classical Euclidean theory of persistent rigid motions to the Lorentzian setting and provide a unified framework connecting curve theory, frame geometry, ruled surfaces, and Lorentzian kinematics. Full article

Nighttime destinations, characterized by distinctive lighting, atmosphere, and activities, provide rich cognitive stimuli for university students. However, university students’ cognition regarding authenticity within such settings remains underexplored. Grounded in psychological empowerment theory, and the cognition–affect–conation framework, this study investigates how university students’ perceptions of objective and existential authenticity (i.e., intrapersonal and interpersonal) in a nighttime destination coincide with the meaning of nighttime destination and subsequent critical reflection. It further investigates the moderating role of nocturnal escapism between the meaning of nighttime destination and critical reflection. Using survey data from 764 university students at the “City of Sleepless in the Song Dynasty,” this research employs Partial Least Squares Structural Equation Modeling (PLS-SEM) and fuzzy-set Qualitative Comparative Analysis (fsQCA). The results indicate that intrapersonal authenticity shows the strongest association with the meaning of nighttime destination and critical reflection. The fsQCA reveals four distinct configurations consistently associated with high critical reflection, highlighting configurational complexity. This study offers insights into university students’ cognition of nighttime destination authenticity and discusses perceived experiential qualities that may coincide with critical reflection. Full article

The final stage of urban logistics does not end at the building entrance but continues within complex, vertically structured indoor environments, where conventional ground-based delivery systems face limitations in efficiency, flexibility, and scalability. This study introduces the concept of last-meter delivery, defined as unmanned aerial vehicle (UAV)-enabled transport from the building envelope to the recipient within global navigation satellite system (GNSS)-denied, building-regulated indoor space, and systematically reviews the literature from two traditionally separate domains: indoor-UAV operation in GNSS-denied spaces, and outdoor-UAV-based logistics. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, 297 studies are synthesized through a two-stream thematic synthesis. The review makes three contributions. First, a unified analytical framework is developed across four dimensions (spatial mobility, logistical capability, social acceptance, and operational coordination) through which the two bodies of literature are shown to be largely complementary, with the gaps in one stream coinciding with the strengths of the other. Second, indoor aerial delivery is found to be subject to a distinct set of operational constraints, including micro-scale navigation accuracy, strict geometric safety envelopes, close human–UAV interaction, and privacy sensitivity, implying that indoor transport-UAVs cannot be realized through simple miniaturization of outdoor platforms but require precision-oriented, human-centric, and building-aware design. Third, the four dimensions are translated into a building-management-oriented indicator framework covering spatial compliance, handover standardization, building information modeling (BIM) integration, occupant consent, and liability allocation, reframing last-meter requirements in terms that are actionable for building planners and facility managers. By framing these challenges within the last-meter perspective, this review identifies the gap between current last-mile theories and emerging in-building aerial logistics and provides a structured foundation for future research. Full article

The 1950s witnessed the emergence of the concept of the ‘everyday’ in architecture, theory and art as a critique of the Modern Movement, environmental change, and the mass housing of the post-war boom years. This period coincided with the global embrace of modern architecture. This article focuses on the concept of the everyday, providing a historical context from the 1950s to the 1980s, and discusses the key figures who shaped the term ‘everyday architecture’ in architectural and urban theory and design. Furthermore, this article explores the relevance of the concept of the everyday in relation to current climate change challenges and demonstrates how the everyday can still inform trajectories for (ecologically) just architecture and urban planning. Full article

This paper investigates explicit coefficient-based estimates for a class of fractional Hermite functions defined through finite power series with Gamma-function coefficients. These functions may be viewed as a fractional Hermite-type family associated with the Caputo fractional derivative of order $\alpha \in (0,1]$. An explicit representation of the fractional derivative is obtained as a finite sum of monomials with computable Gamma coefficients. This representation is used to derive a preliminary uniform estimate on bounded intervals $[0,R]$ with an explicit constant depending on $\alpha$, n, and R. Consistency with the integer-order setting is established by showing that, when $\alpha =1$, the construction reduces to a Hermite-type polynomial family and the Caputo derivative coincides with the ordinary derivative. Explicit asymptotic formulas are obtained for the associated coefficient envelope as $R\to 0^{+}$ and $R\to \infty$. Numerical experiments up to degree $n=7$ show that the ratio between the coefficient envelope and the computed supremum norm remains below approximately $1.45$ for the tested parameter range. In addition, a weighted $L^2$ estimate is derived with respect to a fractional Gaussian-type weight, yielding an explicit coefficient-based bound. The estimates obtained in this work are preliminary in nature, being based on coefficient-wise majorization, and are not claimed to be optimal. Determining sharp constants and establishing genuine norm-comparison inequalities remain open problems. The results presented here provide a rigorous starting point for the study of explicit coefficient-based estimates for fractional Hermite functions and suggest several directions for future research in fractional approximation theory. Full article

In this paper, a non-autonomous enterprise cluster model with feedback controls is investigated. Some new criteria for analyzing the existence and local stability of positive almost periodic solutions are proposed. Methods including coincidence degree theory, Lyapunov method and inequality techniques are used in the present paper. In particular, by means of coincidence degree theory, we obtain some sufficient conditions for the existence of positive almost periodic solutions of the system. Based on Lyapunov stability theory, local stability of positive almost periodic solutions is obtained. To illustrate the applicability and validity of Theorems 1 and 2, a numerical example is presented. It is interesting that almost periodic solutions possess a certain degree of symmetry. Full article

Based on vector wave aberration theory, this paper analyzes the relative positions of the third-order coma node and astigmatism nodes under pupil decenter and proposes an initial structure selection criterion in which the coma node coincides with the geometric midpoint of the two astigmatism nodes. Using this criterion, an F/6 off-axis catadioptric telephoto optical system with a focal length of 900 mm and an entrance pupil diameter of 150 mm was designed. The measured on-axis RMS wavefront error was better than 0.025λ at 632.8 nm. The results demonstrate that the system meets the requirements for high-resolution long-focal-length imaging. Full article

We present a dynamical-system approach to linear inverse problems based on a newly introduced discrepancy measure called the mutual power divergence (MPD). The MPD evaluates the mutual consistency between the measurement and the prediction and serves as a Lyapunov function for constructing a continuous-time dynamical system associated with the inverse problem. The equilibrium points of the system coincide with solutions of the linear model, and their stability is established using Lyapunov theory and LaSalle’s invariance principle. By discretizing the continuous-time dynamics with a multiplicative Euler scheme, we obtain an iterative reconstruction algorithm with multiplicative updates. The resulting iteration constitutes a two-parameter extension of the simultaneous multiplicative algebraic reconstruction technique. Numerical experiments on tomographic reconstruction problems demonstrate that the proposed algorithm achieves improved reconstruction accuracy over existing multiplicative methods. Full article

To investigate the failure characteristics of 3D-printed concrete utility tunnels under loading, a 1:25 scaled model was designed using similarity theory. Vertical loading tests were conducted under soil lateral confinement, and the load–displacement curves, discrete-point strain responses, and crack evolution process were obtained. The test results show that the structure successfully undergoes an elastic stage, a crack development stage, and a plastic failure stage. The incorporated polypropylene fibers exert a bridging effect, enabling the component to retain a certain load-bearing capacity after cracking. Crack distribution was highly heterogeneous: cracks were densest on the top slab, widest on the side walls, and multi-directional on the inner wall. A clear correspondence exists between strain response and crack distribution, with tensile strain zones highly coinciding with crack opening zones. The failure mode generally agrees with the “top slab compression–side wall tensile cracking” characteristic of traditional closed-frame structures. However, the wall thickness deviations induced by the 3D printing process are amplified during internal force redistribution in the statically indeterminate structure, resulting in markedly asymmetric failure of the left and right side walls. Full article

Ongoing global climate change and intensified human activities have increased the frequency and intensity of droughts, posing a serious threat to global ecosystems and agricultural sustainability. However, the seasonally differentiated effects of droughts on cropland phenology and productivity, especially in Northeast China, remain insufficiently understood, limiting the assessment of agro-ecosystem vulnerability and the development of effective adaptation strategies. In this study, the standardized precipitation evapotranspiration index (SPEI) was used to assess the frequency and severity of extreme drought in Northeast China based on run theory. Cropland phenology parameters and productivity were derived from time-series MODIS normalized difference vegetation index (NDVI), and gross primary productivity (GPP) products, which were smoothed using a Savitzky–Golay (S–G) filter. Correlation analyses were conducted to examine regional associations between SPEI-defined drought conditions and cropland phenology and productivity. Results show that: (1) Drought events occurred frequently in the central and southern parts of Northeast China, particularly in the Songnen Plain (5.22 events per decade) and the Liaohe Plain (4.89 events per decade); (2) the Songnen Plain showed significant increases (Sen’s slope > 0, p < 0.05) across all drought metrics over 2001–2020, which coincided with LOS shortening (−0.18 d a⁻¹) and GPP decline (−9.12 g C m⁻² a⁻¹); in contrast, the Sanjiang Plain exhibited slight declines (Sen’s slope, p > 0.05) in drought metrics, resulting in LOS lengthening (0.06 d a⁻¹) and GPP increases (7.84 g C m⁻² a⁻¹); and (3) drought impacts were strongly season-dependent, with autumn droughts showing a stronger association with reductions in crop productivity in local areas of Northeast China. These findings highlight the need to account for crop responses to drought events, which is essential for developing measures to cope with drought and protecting regional food security. Full article

We study a class of wrapping operators acting on the space of formal languages over a fixed finite alphabet. The underlying space is equipped with a length-based ultrametric, in which two languages are close whenever they coincide on all sufficiently short words. We prove that every wrapping operator generated by a finite family of guards with positive total guard length is a contraction. As a consequence, Banach’s contraction principle yields existence and uniqueness of a fixed point for the corresponding recursive language equation, together with convergence of the Picard iteration from an arbitrary initial language. We also obtain an explicit quantitative estimate for the rate of convergence. This makes it possible to determine how many iterations are sufficient to recover the fixed point correctly on all words up to a prescribed length. Several examples illustrate the theory, including operators with different guard lengths and a case showing that convergence in the length-based ultrametric does not coincide with set-theoretic convergence. An application to recursive structures and document validation is also presented, including recursive data formats, abstract syntax trees, and a restricted fragment of JSON schemas. The results provide a formal foundation for validation together with explicit bounds for correctness on inputs of bounded length. Full article

Neuronal excitability manifests itself mainly in the form of non-linear, self-regenerative waves of electricity moving along the surface of neuronal axons. These waves are commonly known as action potentials (APs). Theoretical and experimental investigations of the physical and functional characteristics of APs have broadly followed along the lines of the ionic hypothesis and the associated mathematical model introduced by Hodgkin and Huxley (HH). In the current form of this bioelectrical framework, adopted in mainstream physiology and other biological sciences, the axonal membrane is conceptualized as an electronic circuit where electric current is generated and propelled as a result of the time-dependent opening and closure of voltage-operated ion channel proteins, allowing passive flow of specific ions across and along the membrane, powered by their respective electrochemical gradients. Although representing mainstream research, the bioelectric perspective has been criticized for its narrow focus on the electrical characteristics of APs, whilst ignoring other physical manifestations of the nerve signal, particularly mechanical and thermal changes coinciding with AP propagation. As an alternative, a macroscopic thermodynamics-based acoustic theory has been outlined, in which all electric and non-electric manifestations of the nerve signal are considered as a result of a single density pulse in the axonal membrane carried by a reversible lipid membrane phase transition and momentum conservation. Representing a minority view, however, this unified, acoustic perspective on the physical nature of neuronal excitability is largely ignored by representatives of the bioelectric perspective. Here, we draw special attention to the philosophical dimension of the communication failure between the two communities of scientists. We argue that adherents of the bioelectric perspective favor a mechanist type of explanation, whilst supporters of the acoustic perspective are committed to so-called covering-law types of explanation. We conclude that it is this thus far unrecognized philosophical rift, rather than specific scientific differences in opinion, that blocks fruitful interdisciplinary cooperation necessary for building a comprehensive, fully integrated notion of the physical nature of neuronal excitability. Suggestions of how to bridge this conceptual gap are formulated. Full article

We derive a systematic treatment of one-loop effective potentials for interacting scalar fields in curved spacetimes, providing a general formula valid in arbitrary geometries and explicit results for de Sitter and anti-de Sitter backgrounds. We then compute the effective potential for a scalar $O\left(N\right)$ theory on a de Sitter space in any integer dimension. In $d=3$ and dimensional regularization, we extend the calculation up to two-loops and compute the $\beta$-function and the anomalous mass dimension. They coincide exactly with flat-space results, despite dramatic curvature modifications to physical masses/couplings. The flat limit $R\to \infty$ recovers Coleman–Weinberg, confirming consistency. Working in $d=3$ dimension, we repeat the calculation for $Ad{S}_3$ by using point-splitting regularization, obtaining analogue results for the $\beta$-function and anomalous mass dimension (Dedicated to Jean Pierre Gazeau on his 80th Birthday). Full article

Background/Objective: This study examines how after-hours service demands (AHSD) are associated with dentists’ overall work experience (OWE) through the mediating role of compassion satisfaction (CS) and the moderating role of perceived organizational support (POS). Grounded in the Job Demands–Resources (JD-R) and Conservation of Resources (COR) theories, the study investigates how job demands, emotional resources, and organizational support jointly relate to dentists’ psychological well-being. Methods: Data were collected from 450 dentists across seven major Libyan cities—Tripoli, Benghazi, Misrata, Sabha, Al Bayda, Zawiya, and Derna—using a structured online questionnaire administered between May and August 2025. Results: Partial least squares structural equation modeling (PLS-SEM) results indicated that AHSD were positively associated with both CS and OWE, suggesting that demanding work conditions may, under certain conditions, coincide with more positive professional experiences when perceived as meaningful and supported. CS partially mediated the AHSD–OWE relationship, highlighting its role as a key emotional resource linked to more favorable work experiences. In addition, POS moderated the relationships between AHSD and CS, and between AHSD and OWE, although the effects were relatively modest, indicating that organizational support may provide incremental support in how dentists experience demanding work conditions rather than fundamentally altering these relationships. The moderated mediation analysis further suggested that the indirect association between AHSD and OWE via CS was stronger at higher levels of POS. Conclusions: Overall, the findings refine JD-R and COR perspectives by indicating that job demands, emotional resources, and organizational support are jointly associated with dentists’ work-related well-being in a high-demand healthcare context. Full article