Search Results (25,136)

We propose a lattice structure and space group symmetry, Pmmm (No. 47), for the QCD condensate ground state, whose Wyckoff positions are occupied by the four light quarks and antiquarks $u$, $d$, $\tilde{u}$, $\tilde{d}$. These serve as the fundamental building blocks of both the condensate lattice ground state and the baryonic and leptonic particle excitations embedded within it as topological defects of the nominal Wyckoff occupation, offering a more structured alternative to the QCD instanton liquid picture. Building on Bloch quark wave solutions of a tight-binding Hamiltonian defined on this lattice, we propose a generalization of Einstein’s Equivalence Principle: composite particles embedded in the lattice and propagating by tunnelling cannot distinguish acceleration by gravity, the strong, weak, or electromagnetic forces, or curvature of the lattice itself, arising from local variation in unit cell shape. We derive an eight-by-eight tight-binding Hamiltonian that decouples into two four-by-four blocks separating the quark and antiquark sectors. Electrons, positrons, protons, neutrons, deuterons, and α-particles are embedded in the lattice as defect-induced deviations from the nominal Wyckoff occupation, with their spin and helicity emerging structurally from this picture. We further propose that the lattice’s unit cells carry a small nonzero rest mass, whose collective gravitational effect across a galactic halo may account for the discrepancy between visible mass and rotation curves, identifying the Pmmm condensate as a dark matter candidate. Finally, we outline a mechanism near black hole horizons by which local melting of the condensate lattice followed by quark reactions that conserve the number and flavor of the quarks could yield a new route to baryon asymmetry. We propose a framework that goes several steps beyond the Standard Model by introducing a Pmmm space group unit cell for the QCD condensate ground state, built from the four light quarks and antiquarks $u$, $d$, $\tilde{u}$, $\tilde{d}$. We further propose that topological defects of the Pmmm condensate lattice are the geometric origin of particle excitations. Full article

To investigate the nonlinear dynamic characteristics of magnetic suspended dual-rotor systems, this study examines periodic and quasi-periodic responses induced by bearing nonlinearities, including flux leakage and magnetic saturation effects. A nonlinear dynamic model is established using the finite element method, incorporating unbalance excitation and nonlinear bearing forces. A comprehensive parametric analysis is conducted to evaluate the effects of rotational speed, initial stiffness, and initial damping on the system’s dynamic responses and bifurcation behavior. The results reveal the occurrence of period-5 and quasi-periodic vibrations under nonlinear bearing conditions. In the quasi-periodic regime, low-frequency components dominate, and the force–current characteristics of the magnetic bearings spread over a wider band, reflecting a multi-valued force–current relationship. Furthermore, decreasing initial stiffness and increasing damping advance the onset of quasi-periodic responses and reduce the corresponding critical rotational speed. Notably, through real-time control adjustment, quasi-periodic motion can be converted into periodic motion, thereby distinguishing the system from conventional mechanically supported rotor systems. Experimental results obtained from a magnetic suspended dual-rotor test rig validate both the bearing-force model and the dynamic model, and further reveal periodic variations in system response under different speed ratios. Full article

Pulsar detection holds significant value in spacecraft autonomous navigation, space-based time reference establishment, and space science research. The X-ray telescope is a crucial instrument for pulsar detection, and its focusing mirror—the most critical component—exhibits detection performance directly influenced by the film thickness uniformity. This paper proposes an off-axis biaxial rotation coating method and derives, for the first time, a theoretical model of film thickness distribution on a cylindrical substrate based on classical thin-film deposition theory. Using this model, we systematically analyze the influence of key coating parameters—namely the distances a and b from the evaporation source to the vertical rotation axis and to the horizontal rotation axis, respectively—on thickness uniformity. By optimizing the coating process parameters, the thickness uniformity on the cylindrical substrate is significantly improved. When parameters a and b are within certain ranges and satisfy a specific relationship, a film with thickness uniformity better than 1% can be obtained. Coating experiments are carried out on a mandrel cylinder, and the measured film thickness distribution shows good agreement with theoretical predictions, with a maximum deviation of only 1.2%, thereby validating the accuracy of the proposed model. This work provides a rapid, non-iterative approach for determining coating parameters, significantly improving efficiency and reducing costs. Full article

Introduction: We investigated the effect of transverse maxillary constriction on nasal septal deviation (NSD) and nasal floor slanting. Methods: 60 growing Wistar rats (21 days old) were divided into four groups: (1) Experimental Group 1 received active constriction force (100cN), (2) Experimental Group 2 received active expansion force (100cN), (3) Sham received the same spring as Experimental Groups without receiving any active force, and (4) Control group did not receive any appliance. Samples were collected after 28 days for microcomputed tomography (μCT) analysis. Results: Experimental Group 1 demonstrated maxillary constriction (both skeletal and dental), accompanied by mandibular shift on closure, clockwise mandibular rotation, and increased mandibular plane angle and facial height. Constriction was also associated with severe nasal floor slanting in the molar area that extended posteriorly. Nasal floor canting was accompanied by a slanted vomer and a C-shaped NSD. The direction of nasal floor canting and mandibular shift was always similar. Experimental Group 2, on the other hand, was not associated with nasal deviation, and a slight slanting of the nasal floor was observed only when there was a mandibular shift. Conclusions: Our study suggests that the constricting transverse forces applied to the maxilla can be associated with nasal septal deviation. One possible mechanism by which constriction contributes to nasal septal deviation is by promoting mandibular shift. Mandibular shift, in turn, dictates the direction of slanting of the nasal floor and, consequently, the vomer, which may, in turn, lead to nasal septal deviation. Full article

Cryptocurrency market infrastructure—public blockchains and cross-chain bridges supporting tens of billions in liquidity—is monitored as a systemic-risk surface by the Financial Stability Board and equivalent bodies, with defensive posture calibrated against human-level adversaries. Anthropic’s April 2026 release of Claude Mythos Preview has prompted institutional response across financial regulation but no blockchain-specific analytical framework. This paper develops one by defining Mythos-class as a vendor-neutral capability profile: a set of frontier autonomous offensive capabilities specified independently of any single model or vendor (defined by five constituent capability primitives). The central analytical claim is friction inversion: the patch primitives, segmentation, vendor-coordinated disclosure, and credential rotation that constrain Mythos-class capability in conventional IT environments are structurally absent on-chain. This makes blockchain exposure positioned differently in kind, not degree, from enterprise IT. The paper instantiates this finding against Bitcoin and Ethereum/L2 architectures through analysis of four major bridge exploits totaling over $1.74 billion in losses. Vendor-neutral defensive and governance frameworks defined against the capability profile rather than any specific model release are the correct unit of analysis. On this basis the paper offers general recommendations for protocol governance, audit and verification cadence, and regulatory posture, developed as an analytical framework rather than as empirically validated risk estimates. Full article

Quadruped robots can extend their utility beyond locomotion by using a leg as a non-prehensile end-effector to push objects, but this requires combining global planning with adaptive contact control. We present a hybrid framework that couples Rapidly exploring Random Trees (RRT) for global motion planning with Proximal Policy Optimization (PPO) for local leg-pushing control, evaluated in a CoppeliaSim simulation of a Spot-like quadruped pushing a box to a goal pose. The PPO action consists of Bézier control-point parameters and a leg-selection index, and the reward combines positional error, angular error, and a stability penalty. The agent learns straight-line pushing. Without retraining, a fixed asymmetric Bézier action induces a consistent rotation at $\omega \approx 4–5\times {10}^{-4}$ rad/s, and the resulting circular arcs are composed—in the spirit of Dubins paths—to follow curved trajectories. For box masses from $0.1$ kg to $0.9$ kg (up to eight times the training mass), angular and position errors grew approximately linearly from $0.59°$ to $6.32°$ and $0.18$ m to $0.64$ m, respectively, with no abrupt divergence. A single learned pushing primitive, combined with sampling-based planning and a deterministic composition rule, generates both straight-line and curved manipulation. Full article

The rotational error motion of precision aerostatic rotary stages substantially affects the accuracy of machining and measuring equipment. A comprehensive and flexible error modeling method is absent. This paper develops an analytical model for the error motion of an aerostatic rotary stage bearing, utilizing linear superposition and spatial force equilibrium principles. The error motion of an orifice-restricted rotary stage is computed using this approach. The impact of bearing manufacturing inaccuracies (e.g., journal roundness, thrust plate profile) and micro-vibrations caused by internal turbulence is analyzed. Finally, the model was validated experimentally using the reversal method. The results indicate that bearing manufacturing errors positively correlate with error motion, and micro-vibration considerably influences errors at the sub-100 nm level. The relative error between the predicted and measured values is less than 15%, confirming the validity and applicability of this modeling and analytical approach. This research enhances error motion analysis methods and offers a novel constructive reference for predicting and optimizing error motion in precision aerostatic rotary stages. Full article

High-speed electric machines enhance power density and eliminate the need for a gearbox in waste heat recovery microturbine systems. However, existing designs often suffer from high manufacturing costs and complex cooling requirements. This study presents the development, experimental validation, and comparative analysis of three high-speed machine designs. First, a lower-speed induction machine prototype, constructed using standardized components, was tested at an operating speed of 13,000 rpm. This prototype enabled experimental validation of the numerical model used for loss calculations. Experimental results showed total losses of 7.89 kW, closely matching the simulated value of 7.75 kW at an output power of 93.1 kW, i.e., an efficiency of 92.19%. Building on these findings, two smaller machine prototypes were developed: one featuring an induction squirrel-cage rotor and the other employing a surface-mounted permanent magnet rotor topology. Both machines were designed and evaluated using finite element analysis and conjugate heat transfer simulations. Their performance was analyzed under both sinusoidal and pulse-width-modulated voltage supply conditions. At an operating speed of 14,000 rpm, the permanent magnet machine outperformed the induction machine, achieving 63.2 kW of mechanical power and an efficiency of 96.21%, while operating at lower temperatures. In comparison, the induction machine delivered 52.4 kW of mechanical power with an efficiency of 94.64%. The primary novelty and contribution of this work lie in the implementation of a two-pole machine architecture capable of achieving an output power of 100 kW at operating speeds between 20,000 and 25,000 rpm. Compared with similar solutions reported in the literature, the proposed machines feature a simplified bearing arrangement and a more straightforward liquid-cooling system. These characteristics have the potential to reduce manufacturing costs and simplify maintenance during operation. Full article

Periodic abnormal vibration in large pressurized water reactor (PWR) nuclear steam turbine generator units is difficult to diagnose because the parameter-level link among three-pad tilting-pad journal bearings, oil-film thermal asymmetry, and possible Morton-effect susceptibility remains insufficiently quantified. This study investigates an ARABELLE-type unit and establishes a finite-difference bearing rotor model by solving the oil-film thickness equation, Reynolds pressure equation, two-dimensional energy equation, pad moment balance, and linearized stiffness and damping coefficients. The bearing load, radial clearance, rotational speed, and inlet oil temperature are examined as controllable variables, while only the calculated pad temperature rises are directly validated against field measurements from eight support bearings. The calculated temperature rise deviations range from −7% to 8%, with a root-mean-square deviation of approximately 0.32 °C and a mean absolute percentage error of approximately 4.2%. The model results suggest that the load and speed mainly intensify the total oil-film heating, whereas the radial clearance and inlet oil temperature more directly govern the circumferential temperature difference, used here as an indirect indicator of the Morton effect risk. For the investigated Bearing 3, a radial clearance near 0.52 mm and an inlet oil temperature of 48–52 °C are suggested as bearing-specific operating windows for reducing thermal imbalance while maintaining engineering stability. The main contribution is a traceable engineering chain from field abnormal vibration to three-pad bearing thermal asymmetry, cautious Morton-effect risk interpretation, and operational adjustment for large nuclear rotating machinery. Full article

Shapelet-based classifiers offer structural interpretability: discriminative subsequences form an inspectable vibration-pattern vocabulary and a shallow decision-tree ensemble produces traceable fault-type predictions. We impose explicit interpretability constraints on the model and apply Bayesian optimisation within this bounded region; the primary experimental question is whether these constraints carry a performance penalty relative to an unconstrained baseline. Evaluation uses recording-level cross-validation on CWRU (Case Western Reserve University) and MFPT (Machinery Failure Prevention Technology) bearing datasets with Hilbert envelope demodulation. The central finding is that the constraints impose no systematic performance penalty: the shapelet classifier matches ROCKET, a non-interpretable baseline, on both datasets, with cross-validated mean F1 differences smaller than the fold-to-fold standard deviation. To further characterise the selected models under the controlled laboratory conditions studied here, we assess probability calibration and conformal prediction coverage as secondary analyses. Raw probability estimates are well-calibrated, but Platt scaling degrades under cross-severity distribution shift; split conformal prediction yields valid coverage on CWRU but fails on MFPT due to class-proportion mismatch across recording-level splits. Together, these results show that structural constraints supporting interpretability are compatible with competitive performance, and identify the conditions under which reliability tools succeed and fail in this setting. Full article

In planetary radar observations, accurately scaled inverse synthetic aperture radar (ISAR) images are essential for near-Earth asteroid (NEA) shape reconstruction, rotational-state estimation, and impact risk assessment. However, conventional ISAR cross-range scaling methods typically rely on time–frequency analysis or multidimensional parameter searches, resulting in high computational complexity and limited robustness under the low signal-to-noise ratio (SNR) conditions commonly encountered in NEA observations. To address this challenge, this paper proposes a joint ISAR phase autofocus and cross-range scaling framework based on adaptive phase tracking (APT). The method employs a multi-scale Laplacian of Gaussian (LoG) detector to extract isolated scatterers and reformulates Doppler chirp-rate estimation as a recursive state estimation problem. By adaptively tracking the cross-range Doppler phase of these scatterers, the target’s effective rotation velocity is directly estimated without exhaustive parameter searches. A unified phase compensation function is then constructed to simultaneously achieve range-dependent autofocus and cross-range scaling. Simulation results based on a three-dimensional NEA model with realistic planetary radar imaging parameters demonstrate the effectiveness of the proposed method in near-Earth asteroid imaging scenarios. Experimental results from a UAV turntable setup further verify its capability for cross-range scaling and phase autofocus in a controlled near-field ISAR imaging scenario. These results show that the proposed framework achieves high estimation accuracy and robustness with reduced computational cost, making it an efficient and reliable solution for practical ISAR imaging in challenging radar environments. Full article

We investigate the effects of Lorentz invariance violation (LIV) on the resonance structure of the Z boson in high-energy collider experiments. Building on previous work where resonance line-shape distortions were established, we extend the analysis to include spacelike and lightlike orientations of the LIV vector. The modified dispersion relation induces rapidity-dependent distortions of the resonance profile, with effects growing strongly at large rapidities. In anisotropic scenarios, the signal exhibits characteristic sidereal-time modulation due to the rotation of the Earth relative to the preferred LIV direction. We show that, while global analyses dilute the effect, dedicated studies focusing on high-rapidity bins and sidereal-time dependence can significantly enhance sensitivity. The resulting shifts in reconstructed resonance parameters can reach or exceed current experimental precision for LIV scales as low as ${\delta }_{LIV}\sim {10}^{-8}$. These results demonstrate that collider measurements of unstable gauge bosons provide a complementary and competitive probe of Lorentz violation. Full article

A hypothesis was proposed that continuous dual-circuit mixing can be achieved by equipping a feed mixer-distributor with two leveling–mixing finger shafts, which, after lifting the feed mass to a certain height, collect it in the central part of the hopper and divide it into two flows directed toward the end walls of the hopper. In this case, continuous dual-circuit mixing is performed during each rotation of the leveling–mixing shaft. A structural and technological scheme, engineering documentation, and an experimental prototype of the feed mixer-distributor were developed. The machine consists of a 3.0 m³ hopper, two horizontal augers, two leveling–mixing finger shafts, a loading conveyor, and a drive mechanism. Theoretical investigations were carried out, and analytical expressions were obtained to determine the circumferential velocity of the fingers of the leveling–mixing device. This velocity must ensure the movement of the feed mixture without scattering and guarantee the release of the feed mass from the finger surface when the finger rotation angle exceeds 20°. Calculations based on the obtained analytical expressions showed that the critical circumferential velocity of the fingers is 0.866 m/s, while the calculated minimum rotational speed of the finger shaft is 20.7 min⁻¹. Therefore, a rotational speed of approximately 20 min⁻¹ was adopted for the experimental investigations. Experimental studies conducted at different rotational speeds of the leveling–mixing device showed that the optimal rotational speed of the finger shaft is 20 min⁻¹. At this rotational speed, the mixture uniformity exceeded 90%. An analytical expression was also derived to determine the velocity of feed mixture movement along the finger surface. Calculations showed that the optimal velocity ranged from 0.5 to 0.94 m/s. This value corresponds to the rational velocity of feed mixture transportation toward the end walls of the hopper. Laboratory experiments were carried out using the feed mixer-distributor at a leveling–mixing finger shaft rotational speed of n = 20 min⁻¹. The optimal mixing time required to achieve the target mixture uniformity was 5.5 min under the tested operating conditions. Comparative experiments also showed that operation of the feed mixer-distributor without the leveling–mixing device resulted in a 34% higher power consumption than operation with the leveling–mixing device. Full article

We propose a systematic way to construct trigonometric-like functions beyond the classical sine–cosine pair by factorising rational expressions in the umbral operator and then evaluating their action on the vacuum. The guiding idea is simple: the usual trigonometric functions may be viewed as cyclic components arising from a finite factorisation, and the same principle can be extended to an n-fold decomposition of rational umbral expressions. For each integer $n\ge 2$, the construction produces n functions which play the role of higher-order trigonometric-like components: their sum reconstructs the corresponding umbral function, while the individual components isolate the different cyclic sectors of its expansion. The construction is developed first in the formal umbral setting. The quadratic case $n=2$ gives the Gaussian-trigonometric functions, in which the cosine-like component is a Gaussian and the sine-like component is its natural umbral companion. The cubic case $n=3$ yields a three-component cyclic system and shows how the same idea extends beyond the usual even–odd decomposition. These examples suggest that trigonometric factorisation is not restricted to ordinary rotations, but belongs to a broader cyclic principle in umbral calculus. We then reinterpret the same formal identities through the recently developed analytic umbral framework. In this second step, the cyclic components are realised by Mellin–Barnes pairings, and the root-of-unity decomposition is related to the splitting of the corresponding spectral kernel. This analytic formulation provides contour representations and local expansions for the functions obtained formally, while also fixing the branch and residue conventions needed for their analytic continuation. Finally, we indicate how the same cyclic kernels act as deformations of the Fourier transform. The resulting framework presents higher-order umbral trigonometric functions as natural cyclic components of factorised rational or exponential umbral operators. Full article

Eco-anxiety has emerged as an important construct in environmental psychology. The Hogg Eco-Anxiety Scale (HEAS-13), which consists of 13 items, is a multidimensional instrument designed to assess affective symptoms, rumination, behavioral responses, and anxiety related to environmental issues. This study examined the psychometric properties of the HEAS-13 in a general population sample from Czechia. The study assessed the scale’s validity in relation to generalized anxiety and self-reported housing damage associated with adverse weather-related events. Data were collected by conducting face-to-face interviews with a population-based sample in Czechia (n = 1027), with respondents selected using address-based sampling. The psychometric evaluation included descriptive statistics, an internal consistency analysis, inter-item correlations, an exploratory factor analysis (EFA) based on principal axis factoring with oblimin rotation, a confirmatory factor analysis (CFA) using a Weighted Least Squares Mean and Variance (WLSMV) estimator appropriate for ordinal indicators, and convergent, discriminant, and known-groups validity testing. The HEAS-13 demonstrated high internal consistency (Cronbach’s alpha = 0.962; McDonald’s omega = 0.958 for the total scale). EFA supported the original four-factor structure and CFA showed a good fit of the original model. Score distributions were positively skewed, and substantial floor effects indicated generally low levels of eco-anxiety symptom endorsement in the general population. The HEAS-13 total score was strongly correlated with the GAD-7 (rho = 0.839) supporting convergence with generalized anxiety, but also indicating possible construct overlap. Known-groups validity was supported by higher HEAS-13 scores among respondents reporting hazard-related home damage. Measurement invariance was examined across sex and age groups. The HEAS-13 appears to be a reliable and structurally well-fitted instrument for assessing multidimensional eco-anxiety in population-based research. The results provide evidence that the construct is meaningfully associated with generalized anxiety and experience of environmentally disruptive events. The HEAS-13 may serve as a useful tool for future research on environmental distress and climate- and environment-related mental health. It may also be useful for studies examining risk perception as an explanatory, associated, or contextual variable. Full article