Search Results (100)

Stylolites, common dissolution surfaces in carbonate rocks, form due to localized stress-induced pressure-solution during burial compaction or tectonic contraction. Their morphology and growth are influenced by dissolution kinetics, rock heterogeneity, clay content, burial depth, stress evolution, diagenesis, and pore fluid availability. This study applies the stylolite roughness inversion technique (SRIT), a proven paleopizometer that quantifies the principal vertical stress (σ_v = σ₁) prevailing in strata in the last moments of bedding-parallel stylolites (BPS) formation, to the Late Cretaceous Bagh Group carbonates in the Narmada Basin, India, to estimate their burial paleo-depth. Using the Fourier Power Spectrum (FPS), we obtained 18 σ₁ values from a collection of 30 samples, enabling us to estimate paleo-burial depths for the Bagh Group ranging from 660 to 1320 m. As the Bagh Group burial history is unknown, but as there is no subsequent sedimentary deposition above it, we relate this ca. 1.3 km burial depth to the now eroded thickness of the deposits related to Deccan volcanism at the end of the Cretaceous time, implying a quasi-instantaneous development of the BPS population in the strata. This research highlights the robustness of SRIT for reconstructing burial histories in carbonate sequences and that it can be a reliable way to reconstruct the thickness of eroded deposits in well-constrained geological history. Full article

This study addresses a critical deficiency in real estate management by examining how contractual arrangements between property owners and facility managers (FMs) can mitigate reputational damage arising from third-party liability incidents. While Spanish regulations impose comprehensive conservation and maintenance duties on property owners, current contractual frameworks inadequately protect owners from reputational risks when damages occur due to FMs’ negligence or operational failures. This conceptual study employs a systematic analysis of 16 Spanish regulations governing real estate conservation and maintenance duties, complemented by an examination of the statutory contract law and a Strengths, Weaknesses, Opportunities, and Threats (SWOT) analysis to evaluate the proposed solutions. The analysis reveals four distinct liability attribution blocks, ranging from quasi-objective owner liability to full objective installation holder liability. Current service contracts between owners and FMs provide insufficient reputational protection, as civil liability remains with the property owners regardless of the FMs’ performance. This study identifies specific contractual mechanisms—combining statutory work contracts with representative mandates and installation ownership transfers—that effectively redirect tort liability from owners to FMs. While this study focuses on Spanish regulatory frameworks as a methodologically necessary foundation for theoretical development, the conceptual framework provides transferable mechanisms for adaptation to other civil law jurisdictions. This study constitutes the first comprehensive analysis bridging legal architecture and facility management to propose novel liability transfer mechanisms within established frameworks. Full article

Methane (CH₄) emissions from dairy farming represent a substantial yet under-quantified share of agricultural greenhouse gas emissions. This study provides an in-depth, satellite-based fingerprinting analysis of methane emissions from Canada’s dairy sector, using Sentinel-5P/TROPOMI data. We utilized a robust quasi-experimental design, pairing 14 dairy-intensive zones with eight non-dairy reference regions, to analyze methane emissions from 2019 to 2024. A dynamic, region-specific baseline approach was implemented to remove temporal non-stationarity and isolate dairy-specific methane signals. Dairy regions exhibited consistently higher methane concentrations than reference areas, with an average methane anomaly of 17.4 ppb. However, this concentration gap between dairy and non-dairy regions notably narrowed by 57.23% (from 24.42 ppb in 2019 to 10.44 ppb in 2024), driven primarily by accelerated methane increases in non-dairy landscapes and a pronounced one-year contraction during 2022–2023 (−39.29%). Nationally, atmospheric methane levels rose by 3.83%, revealing significant spatial heterogeneity across provinces. Notably, an inverse relationship between the initial methane concentrations in 2019 and subsequent growth rates emerged, indicating spatial convergence. The seasonal analysis uncovered consistent spring minima and fall–winter maxima across regions, reflecting the combined effects of seasonal livestock management practices, atmospheric transport dynamics, and biogeochemical processes. The diminishing dairy methane anomaly suggests complex interplay of intensifying background methane emissions from climate-driven wetland fluxes, increasing fossil fuel extraction activities, and diffuse agricultural emissions. These findings underscore the emerging challenges in attributing sector-specific methane emissions accurately from satellite observations, highlighting both the capabilities and limitations of current satellite monitoring approaches. Full article

Fire extinguisher inspectors face ergonomic risk factors and are exposed to several musculoskeletal disorders (MSDs). The aim of this study was to design and evaluate a mobile lift device to reduce the risk of musculoskeletal injuries among fire extinguisher inspectors. This was followed by a quasi-experimental trial among 28 workers, using surface electromyography (EMG), in which muscle activity with percentage of maximum voluntary contraction (MVC), postural analysis using the Rapid Entire Body Assessment (REBA), perceived exertion, and perceived ease of use among workers were evaluated during the fire extinguisher inspection process employing a manual fire extinguisher and using a mobile lift device. The results of the EMG measurement of the muscle activity in the biceps brachii, triceps brachii, middle deltoid, and upper trapezius were obtained using the MVC parameter. The MVC parameter was employed to normalize the EMG signals, allowing for a standardized comparison of muscle activation levels across different tasks and conditions. The results showed a significant positive effect on the muscle activity of the middle deltoid and biceps brachii; the posture risk level and rating for perceived exertion with the mobile lift device were generally lower than those of manual lifting (p < 0.001). With the mobile lift device, there was significant reduction in the muscle activity of the triceps brachii and upper trapezius (p < 0.05). Accordingly, mobile lift devices were found to be useful due to the reduced muscle effort, and postural risks were reduced when using the mobile lift device. Further studies are needed for modifications to the lift assist device based on ergonomic measures of muscle activity and user tests by adjusting the task to suit the capabilities of workers. Full article

This numerical study addressed the multi-objective optimization of a rocket-type Pulse Detonation Engine nozzle. The Pulse Detonation Engine consisted of a constant length, constant diameter cylindrical section plus a nozzle that could be either convergent, divergent, or convergent–divergent. The space of five design variables contained: equivalence ratio of the H2-Air mixture, convergent contraction ratio, divergent expansion ratio, dimensionless nozzle length, and convergent to divergent length ratio. The unsteady Euler-type numerical solver was quasi-one-dimensional with variable cross-sectional area. Chemistry was simulated by means of a one-step global reaction. The solver was used to generate three coarse five-dimensional data tensors that contained: specific impulse based on fuel, total impulse, and nozzle surface area, for each configuration. The tensors were decomposed using the High Order singular Value Decomposition technique. The eigenvectors of the decompositions were used to generate continuous descriptions of the data tensors. A genetic algorithm plus a Gradient Method optimization algorithm acted on the densified data tensors. Five different objective functions were considered that involved specific impulse based on fuel, total impulse, and nozzle surface area either separately or in doublets/triplets. The results obtained were discussed, both qualitatively and quantitatively, in terms of the different objective functions. Design guidelines were provided that could be of interest in the growing area of Pulse Detonation Engine engineering applications. Full article

Involving w-distances and hybrid contractions that combine conditions of the Ćirić type and Samet et al. type, we obtain some general fixed-point results for quasi-metric spaces from which powerful and significant fixed-point theorems on partial metric spaces are deduced as special cases. We present examples showing that our results are real generalizations of those corresponding to the partial metric case and we give an application to the study of recursive equations where the usual Baire partial metric on a domain of words is replaced with a suitable w-distance. Our approach is inspired on the nice fact, stated by Matthews, that every partial metric induces a weighted quasi-metric. Then, we define the notion of a strong w-distance and deduce that every partial metric is a symmetric strong w-distance for its induced weighted quasi-metric space. Full article

In this paper, we introduce several new concepts: generalized neutrosophic rectangular b-metric-like spaces (GNRBMLSs), generalized intuitionistic rectangular b-metric-like spaces (GIRBMLSs), and generalized fuzzy rectangular b-metric-like spaces (GFRBMLSs). These innovative spaces can expand various topological spaces, including neutrosophic rectangular extended b-metric-like spaces, intuitionistic fuzzy rectangular extended b-metric-like spaces, and fuzzy rectangular extended b-metric-like spaces. Moreover, we establish Banach’s fixed point theorem and Ćirić’s quasi-contraction theorem with respect to these spaces, and we explore an application regarding the existence and uniqueness of solutions for fuzzy fractional delay integro-differential equations, as derived from our main results. Full article

In this study, the effects of applied pressure (0, 90, 120, and 150 MPa) during solidification on the microstructure, mechanical properties, and impact–abrasive wear resistance of Cr-Mn-Mo steel prepared by squeeze casting were systematically investigated. The results demonstrated that the materials produced under pressure showed smaller grains compared to those of the samples fabricated without pressure. Compared to the unpressurized sample, the grain diameter of the sample prepared at 120 MPa decreased by 37.7%, the length of the primary arm shortened by 40.7%, and the spacing of the secondary arm contracted by 14.1%. Furthermore, the impact toughness results indicated that the samples prepared without pressure exhibited brittle fracture characteristics, whereas quasi-destructive fractures predominated in the samples prepared at 120 MPa. Simultaneously, three-point bending strength exhibited a gradual increase with increasing pressure, reaching a maximum value of 855.5 MPa when prepared under 150 MPa. Additionally, the impact–abrasive wear resistance of Cr-Mn-Mo alloyed steel produced by squeeze casting was significantly enhanced compared to the samples produced without pressure. The samples without external pressure exhibited a combination of abrasive and adhesive wear, whereas the wear characteristics of the samples prepared under pressure includes grooves, cutting marks, flaking pits, and accumulating ridges. Full article

We consider the concept of fuzzy $\mathcal{H}$-quasi-contraction ($\mathcal{F}\mathcal{H}$-$\mathcal{Q}\mathcal{C}$ for short) initiated by Ćirić in tripled fuzzy metric spaces ($\mathcal{T}$-$\mathcal{F}\mathcal{M}\mathcal{S}$s for short) and present a new fixed point theorem ($\mathcal{F}\mathcal{P}\mathcal{T}$ for short) for $\mathcal{F}\mathcal{H}$-$\mathcal{Q}\mathcal{C}$ in complete $\mathcal{T}$-$\mathcal{F}\mathcal{M}\mathcal{S}$s. As an application, we prove the corresponding results of the previous literature in setting fuzzy metric spaces ($\mathcal{F}\mathcal{M}\mathcal{S}$s for short). Moreover, we obtain theorems of sufficient and necessary conditions which can be used to demonstrate the existence of fixed points. In addition, we construct relevant examples to illustrate the corresponding results. Finally, we show the existence and uniqueness of solutions for integral equations by applying our new results. Full article

In this work, we introduce a new type of multivalued fuzzy proximal quasi-contraction. These are generalized contractions which are a hybrid of $\mathcal{H}$-contractive mappings and quasi-contractions. Furthermore, we establish the best proximity point results for newly introduced fuzzy contractions in the context of fuzzy b-metric spaces. Fuzzy b-metric spaces are more general than fuzzy metric spaces and are linked with the cosine distance, which is used in various contexts of artificial intelligence to measure the similarity between elements of a vector space. Full article

In this paper, a large class of contractions is studied that contains Banach and Matkowski maps as particular cases. Sufficient conditions for the existence of fixed points are proposed in the framework of b-metric spaces. The convergence and stability of the Picard iterations are analyzed, giving error estimates for the fixed-point approximation. Afterwards, the iteration proposed by Kirk in 1971 is considered, studying its convergence, stability, and error estimates in the context of a quasi-normed space. The properties proved can be applied to other types of contractions, since the self-maps defined contain many others as particular cases. For instance, if the underlying set is a metric space, the contractions of type Kannan, Chatterjea, Zamfirescu, Ćirić, and Reich are included in the class of contractivities studied in this paper. These findings are applied to the construction of fractal surfaces on Banach algebras, and the definition of two-variable frames composed of fractal mappings with values in abstract Hilbert spaces. Full article

Picard iteration is on the basis of a great number of numerical methods and applications of mathematics. However, it has been known since the 1950s that this method of fixed-point approximation may not converge in the case of nonexpansive mappings. In this paper, an extension of the concept of nonexpansiveness is presented in the first place. Unlike the classical case, the new maps may be discontinuous, adding an element of generality to the model. Some properties of the set of fixed points of the new maps are studied. Afterwards, two iterative methods of fixed-point approximation are analyzed, in the frameworks of b-metric and Hilbert spaces. In the latter case, it is proved that the symmetrically averaged iterative procedures perform well in the sense of convergence with the least number of operations at each step. As an application, the second part of the article is devoted to the study of fractal mappings on Hilbert spaces defined by means of nonexpansive operators. The paper considers fractal mappings coming from $\phi$-contractions as well. In particular, the new operators are useful for the definition of an extension of the concept of $\alpha$-fractal function, enlarging its scope to more abstract spaces and procedures. The fractal maps studied here have quasi-symmetry, in the sense that their graphs are composed of transformed copies of itself. Full article

Since the topological properties of a b-metric space (which generalizes the concept of a metric space) seem sometimes counterintuitive due to the fact that the “open” balls may not be open sets, we review some aspects of these spaces concerning compactness, metrizability, continuity and fixed points. After doing so, we introduce new types of contractivities that extend the concept of Banach contraction. We study some of their properties, giving sufficient conditions for the existence of fixed points and common fixed points. Afterwards, we consider some iterative schemes in quasi-normed spaces for the approximation of these critical points, analyzing their convergence and stability. We apply these concepts to the resolution of a model of integral equation of Urysohn type. In the last part of the paper, we refine some results about partial contractivities in the case where the underlying set is a strong b-metric space, and we establish some relations between mutual weak contractions and quasi-contractions and the new type of contractivity. Full article

In this paper, we introduce and examine the notion of a protected quasi-metric. In particular, we give some of its properties and present several examples of distinguished topological spaces that admit a compatible protected quasi-metric, such as the Alexandroff spaces, the Sorgenfrey line, the Michael line, and the Khalimsky line, among others. Our motivation is due, in part, to the fact that a successful improvement of the classical Banach fixed-point theorem obtained by Suzuki does not admit a natural and full quasi-metric extension, as we have noted in a recent article. Thus, and with the help of this new structure, we obtained a fixed-point theorem in the framework of Smyth-complete quasi-metric spaces that generalizes Suzuki’s theorem. Combining right completeness with partial ordering properties, we also obtained a variant of Suzuki’s theorem, which was applied to discuss types of difference equations and recurrence equations. Full article