Fast Roll Research Articles

Unveiling the nonlinear dynamics of a rolling axion during inflation

A spectator axion-gauge sector, minimally coupled to the inflaton, with the axion experiencing a momentary stage of fast roll during cosmological inflation, can generate unique signatures in primordial density fluctuations and the gravitational wave background. We present the first lattice simulation of this system using a novel hybrid numerical scheme. This approach solves the fully nonlinear dynamics of the axion-gauge sector while treating the gravitational interaction between the axion and inflaton linearly. Initially, we test the validity of the WKB approximation in the linear regime. We then investigate strong backreaction dynamics within the axion-gauge sector. Our findings reveal that backreaction significantly suppresses the growth of the gauge field and the amplitude of scalar perturbations. The simulation also allows us to analyze the non-Gaussianity of scalar fluctuations, including higher-order statistics. We show that, although non-Gaussianity is suppressed by strong backreaction, it remains higher than in the minimal model where the axion coincides with the inflaton. Our results highlight the need for simulations to make robust predictions to test against data from gravitational wave interferometers and large-scale structure surveys.

Primordial Black Holes Generated by Fast-roll Mechanism in Noncanonical Natural Inflation

In this work, a new fast-roll (FR) mechanism to generate primordial black holes (PBHs) and gravitational waves (GWs) in generalized noncanonical natural inflation is introduced. In this model, choosing a suitable function for noncanonical mass scale parameter M(ϕ) gives rise to produce a cliff-like region in the field evolution path. When inflaton rolls down the steep cliff, its kinetic energy during an FR stage increases in comparison with a slow-roll stage. Hence, seeds of PBH production are born in this transient FR stage. Depending on the position of the cliff, appropriate cases of PBHs for explaining total dark matter, microlensing effects, LIGO–Virgo events, and NANOGrav 15 yr data can be formed. The density spectrum of GWs related to one case of the model lies in the NANOGrav 15 yr domain and behaves like ΩGW0∼f5−γ . The spectral index γ = 3.42 for this case satisfies the NANOGrav 15 yr constraint. Moreover, regarding reheating considerations, it is demonstrated that PBHs are born in the radiation-dominated era. Furthermore, viability of the model in light of theoretical swampland criteria and observational constraints on cosmic microwave background scales are illustrated.

Effects of Roller Milling Parameters on Wheat-Flour Damaged Starch: A Comprehensive Passage Analysis and Response-Surface Methodology Optimization.

Damaged starch typically arises from mechanical damage caused by the action of the roller mills during the wheat flour milling process. The content of resulting damaged starch in the flour significantly influences its characteristics, emphasizing the importance of understanding and controlling the formation of damaged starch for the production of specialized flours. A detailed passage analysis from three different commercial mills revealed that starch damage control is primarily achievable at front passages of the sizing and reduction system, which generate the majority of the flour release in the mill. Also, it revealed that damaged starch content increases progressively from the initial to the final passages during milling in the break, sizing and reduction system. To investigate the effects of milling parameters on damaged starch, flour yield, and energy consumption, a three-level and three-variable Box-Behnken experimental design with response surface methodology was applied. As independent variables roll gap (0.05-0.35 mm), feed rate (0.15-0.35 kg/cm min), and fast roll speed (400-800 rpm) were employed. The obtained models were utilized to optimize milling conditions for producing flours with special characteristics.

Effect of heat treatment before fast multiple rotation rolling on friction surfaced Al–Si–Cu alloy

In this study the effect of combination of heat treatment of consumable rod and solid solution heat treatment before fast multiple rotation rolling (FMRR) processing on microstructure, mechanical property and wear resistance of Al–Si–Cu alloy friction surfaced on commercial pure aluminum alloy were investigated. Results show that after the FMRR process, there is a significant reduction (99% reduction) in the friction surfaced coating surface roughness. The surface roughness after FMRR processing in the coatings created by homogenized and solid solution treated consumable rod is 0.74 ± 0.12, and 0.56 ± 0.08 μm, respectively. In the coating created by homogenized rod the minimum grain size (1.7 ± 0.2 μm) formed in the FMRR processed layer. Using homogenized consumable rod and FMRR processing by rotational speed of 3000 rpm and traverse speed of 140 mm/min, the maximum hardness (9.8 ± 0.3 GPa) and minimum wear rate (4.6 ± 0.1 μg/m) created at processed layer. FMRR processing by rotational speed of 3000 rpm and traverse speed of 140 mm/min, result in 27 and 24 % increasing in hardness at friction surfaced coating created by homogenized and solid solution treated consumable rods, respectively.

Enhancing performance: Pre-processing heat treatment's influence on fast multiple rotation rolling of friction-surfaced Al-16Si-4Cu alloy

This study investigated the influence of pre-processing heat treatment on the fast-multiple rotation rolling (FMRR) of Al-16Si-4Cu alloy friction-surfaced onto the AA1050 aluminum substrate. Results showed that applying solid solution treatment before both the friction surfacing and FMRR processes yielded the thinnest coating thickness (1.4 ± 0.2 mm). Moreover, using a solid solution-treated Al-16Si-4Cu alloy rod resulted in the smallest average size of Si particles (4.2 ± 0.1 μm) in the FMRR-treated layer. Additionally, the most uniform distribution and smallest size of Al2Cu precipitates in the FMRR-treated layer were achieved by subjecting the alloy to solid solution treatment prior to both FMRR and friction surfacing. Notably, solid solution treatment preceding both FMRR and friction surfacing processes produced maximum nano-hardness (10.42 ± 0.54 GPa), shear strength (174.32 ± 9.21 MPa), and elastic modulus (221.03 ± 0.54 GPa) in the clad layer. Furthermore, pre-processing with solid solution heat treatment led to the lowest wear rate of the clad layer, exhibiting a reduction of 74.47 % compared to the AA1050 substrate.

Effect of fast multiple rotation rolling on friction surfaced Al[sbnd]Si[sbnd]Cu alloy

In this study, the impact of four linear speeds (75, 95, 115, and 135 mm/min) during fast-multiple rotation rolling (FMRR) on the A390 coating applied via friction surfacing (FS) on the AA1050 substrate was investigated. The microstructure, mechanical properties, and wear resistance were examined using optical microscopy, scanning electron microscopy, electron backscatter diffraction (EBSD), transmission electron microscopy (TEM), nanoindentation tests, microhardness tests, and pin-on-disc tests. Results showed that as the linear speed increased to 135 mm/min, the FMRR-treated layer became 48.6 % thinner. At a linear speed of 135 mm/min, the grain size reduced to 1.24 ± 0.15 μm, and the sizes of Al2Cu and Si particles decreased to 0.51 ± 0.02 μm and 3.45 ± 0.11 μm, respectively. The nano-hardness and Young's modulus increased to 9.11 GPa and 218.9 GPa, respectively. Moreover, the wear rate decreased by 43.53 % compared to the consumable rod and by 65.96 % compared to the AA1050 substrate at a linear speed of 135 mm/min. EBSD results indicated the presence of recrystallization and shear texture components in the FMRR-treated layer. TEM analysis confirmed the presence of nanometer-sized Si particles (<10 nm) and grains (100–500 nm) in the FMRR-processed layer.

Efficient routing in robotic movable fulfillment systems with integer programming: A rolling horizon and heuristic approach

This paper addresses an integrated rack assignment and robot routing problem arising in robotic movable fulfillment systems (RMFS). This NP-hard planning task goes beyond current literature by simultaneously optimizing movable rack selection and multi-agent collision-free path finding, rather than decomposing them. A mixed integer programming (MIP) model with a new level-space-time network representation is proposed, jointly considering reusable racks, robot-rack pairings, storage repositioning, and collision avoidance. To improve computational efficiency, a fast rolling horizon heuristic and greedy algorithm are developed. Extensive experiments demonstrate that the integrated method's solutions can improve by 30 % upon conventional decomposed approaches. Intriguing test cases reveal the model, suggesting non-intuitive robot carryover policies that are unfound by separate selection and routing methods. This indicates potential optimization benefits from explicitly coordinating task assignment, scheduling, and routing decisions in complex automated warehousing systems. The rolling horizon heuristic solutions approach optimality with much greater efficiency than directly solving one large MIP, validating its practical value. This research provides useful integrated modeling insights, efficient solution algorithms, and decision support for efficiently controlling next-generation robotic movable fulfillment systems.

CMB spectral distortions from enhanced primordial perturbations: the role of spectator axions

Primordial scalar and tensor modes can induce Cosmic Microwave Background spectral distortions during horizon re-entry. We investigate a specific mechanism proposed for this purpose, characterized by the coupling of an SU(2) gauge field to an axion undergoing a momentary stage of rapid evolution during inflation. Examining in details the perturbations produced by this model, we find that spectral distortions from the scalar modes significantly dominate those arising from the tensors. This holds true also for an earlier version of the model based on a U(1) gauge field. The scalar-induced distortions might be observed in future experiments, and the current COBE/FIRAS constraints already limit the parameter space of these models. Additionally, we find that delaying the onset of fast roll in the SU(2) scenario (to enhance the modes at the scales relevant for spectral distortions, while respecting the CMB constraints at larger scales) poses a greater challenge compared to the U(1) case. We propose a way to control the axion speed by varying the size of its coupling to the gauge fields.

Surface Property Enhancement of Al–Si–Cu Alloy Coating by Fast Multiple Rotation Rolling

Herein, the effect of high rotational speed fast multiple rotations rolling (FMRR) on the microstructure, mechanical properties, and wear resistance of an Al–Si–Cu alloy coating friction surfaced on AA1050 aluminum alloy is investigated. The FMRR process is performed at a rotational speed of 3000 rpm with traverse speeds of 50, 80, 110, and 140 mm min−1. The microstructure, mechanical properties, and wear resistance are examined by optical microscope, scanning electron microscope, electron backscatter diffraction, transmission electron microscope, nanoindentation test, microhardness test, and pin‐on‐disc wear test. The results show that as the traverse speed increases from 50 to 140 mm min−1, surface roughness decreases from 6.3 ± 0.3 to 3.2 ± 0.2 μm. Additionally, with the increase in traverse speed, the coating height increases from 3.8 ± 0.3 to 4.7 ± 0.4 mm, while the coating width decreases from 37.1 ± 1.1 to 25.4 ± 1.3 mm. Furthermore, as the traverse speed increases from 50 to 140 mm min−1, the average hardness of the FMRR‐processed layer increases from 5.6 ± 0.6 to 10.2 ± 0.6 GPa. At a traverse speed of 140 mm min−1, the wear resistance of the FMRR‐processed layer increases by 20% compared to the Al–Si–Cu alloy consumable rod.

Ca2+ transients on the T cell surface trigger rapid integrin activation in a timescale of seconds

One question in lymphocyte homing is how integrins are rapidly activated to enable immediate arrest of fast rolling lymphocytes upon encountering chemokines at target vascular beds given the slow chemokine-induced integrin inside-out activation. Herein we demonstrate that chemokine CCL25-triggered Ca2+ influx induces T cell membrane-proximal external Ca2+ concentration ([Ca2+]ex) drop in 6 s from physiological concentration 1.2 mM to 0.3 mM, a critical extracellular Ca2+ threshold for inducing αLβ2 activation, triggering rapid αLβ2 activation and T cell arrest before occurrence of αLβ2 inside-out activation. Talin knockdown inhibits the slow inside-out activation of αLβ2 but not [Ca2+]ex drop-triggered αLβ2 quick activation. Blocking Ca2+ influx significantly suppresses T cell rolling-to-arrest transition and homing to skin lesions in a mouse psoriasis model, thus alleviating skin inflammation. [Ca2+]ex decrease-triggered rapid integrin activation bridges the gap between initial chemokine stimulation and slow integrin inside-out activation, ensuring immediate lymphocyte arrest and subsequent diapedesis on the right location.

Joint prediction method for strip thickness and flatness in hot strip rolling process: A combined multi-indicator Transformer with embedded sliding window

Thickness and flatness are important quality indicators for strip. It is important that the rapid and accurate prediction of the exit thickness and flatness for the optimal control of the hot strip rolling process. Due to the fast and long rolling process, there are time delays, non-linearity and strong coupling among the variables, which cause difficulties in the establishment of prediction models. In this paper, the variables related to thickness and flatness are selected by analyzing the rolling process mechanism and data. Based on the data related to the rolling quality, a rolling exit thickness and flatness joint prediction model combined multi-indicator Transformer with embedded sliding window (SW-MTrans) is proposed. First, a sliding window is embedded into the input layer of the model in order to address the effect of the time delay among variables. Then a Transformer network is improved to achieve accurate prediction of thickness and flatness simultaneously. It is verified that the proposed method can predict the thickness and flatness at the same time with higher prediction accuracy and generalization ability compared with other methods through actual production data. The mean absolute error (MAE) for thickness prediction was reduced by 19.37% and MAE for flatness prediction was reduced by 14.03% compared to the existing prediction model.

Rolling contact fatigue analysis of the soft zone for the main bearing in a tunnel boring machine

A hierarchical finite element modeling method is proposed to study the problem of fatigue spalling easily due to low hardness in the soft zone for the main bearing of a tunnel boring machine. Quasi-static analyses of the main bearing are performed based on the global symmetric model and verified by relative displacement tests of the rings. The invariant contact pressure is replaced by the rolling contact of the rollers in the local sub-model. The contact load is used as an input to solve the stress field, and then the effects of soft zone and hardened depth on the contact characteristics and fatigue lifetime of the sub-model are investigated. The results show there are stress peaks at the junction of the hardened and soft zones. The effect of hardened depth on the stress distribution and fatigue lifetime is relatively small. However, the optimum hardened depth is influenced by the contact load and the permissible stress of the material. The minimum lifetime of the raceway during rolling occurs in the soft zone. This paper achieves a fast and effective rolling contact fatigue analysis of the main bearing, which provides a theoretical basis for optimizing the main bearing design.

Cxcl1 monomer-dimer equilibrium controls neutrophil extravasation.

The chemokine Cxcl1 plays a crucial role in recruiting neutrophils in response to infection. The early events in chemokine-mediated neutrophil extravasation involve a sequence of highly orchestrated steps including rolling, adhesion, arrest, and diapedesis. Cxcl1 function is determined by its properties of reversible monomer-dimer equilibrium and binding to Cxcr2 and glycosaminoglycans. Here, we characterized how these properties orchestrate extravasation using intravital microscopy of the cremaster. Compared to WT Cxcl1, which exists as both a monomer and a dimer, the trapped dimer caused faster rolling, less adhesion, and less extravasation. Whole-mount immunofluorescence of the cremaster and arrest assays confirmed these data. Moreover, the Cxcl1 dimer showed impaired LFA-1-mediated neutrophil arrest that could be attributed to impaired Cxcr2-mediated ERK signaling. We conclude that Cxcl1 monomer-dimer equilibrium and potent Cxcr2 activity of the monomer together coordinate the early events in neutrophil recruitment.

From Material Requirements to the Rolling Schedule - Fast Material-Oriented Roll Pass Design for Long Products with the Open Source Framework PyRolL

From Material Requirements to the Rolling Schedule - Fast Material-Oriented Roll Pass Design for Long Products with the Open Source Framework PyRolL

Flattening aluminum plates with tuning asymmetric rolling parameters

The asymmetric rolling (ASR) process can introduce shear strains inside the plate, resulting in the improvements of microstructures and mechanical properties. Its industrial application for rolling the (mid-)thick plates is impeded by the uncontrollable bending behavior. In this study, the influences of rolling parameters on the bending behavior of the rolled AA 7050 aluminum alloy plates were investigated. It is found that the plate will bend towards the slower roll with larger speed ratios and initial plate thickness as well as lower thickness reduction. A flat plate can be obtained by choosing appropriate rolling parameters. The equivalent plastic strain rate distribution is considered to be critical to the plate bending, the downward bending (towards faster roll) would be associated with an obvious increase of the equivalent plastic strain rate at the top surface of the plate near the end of the deformation zone. Multi-pass asymmetric rolling routes considering bending optimization were proposed and verified through rolling trials. As the speed ratio increased from 1.1 to 1.2, the through-thickness plastic strain became more homogeneous and the total rolling pass numbers decreased by 33 % (from 9 passes to 6 passes).

Fast Rolling Shutter Correction in the Wild.

This paper addresses the problem of rolling shutter correction (RSC) in uncalibrated videos. Existing works remove rolling shutter (RS) distortion by explicitly computing the camera motion and depth as intermediate products, followed by motion compensation. In contrast, we first show that each distorted pixel can be implicitly rectified back to the corresponding global shutter (GS) projection by rescaling its optical flow. Such a point-wise RSC is feasible with both perspective and non-perspective cases without the pre-knowledge of the camera used. Besides, it allows a pixel-wise varying direct RS correction (DRSC) framework that handles locally varying distortion caused by various sources, such as camera motion, moving objects, and even highly varying depth scenes. More importantly, our approach is an efficient CPU-based solution that enables undistorting RS videos in real-time (40fps for 480p). We evaluate our approach across a broad range of cameras and video sequences, including fast motion, dynamic scenes, and non-perspective lenses, demonstrating the superiority of our proposed approach over state-of-the-art methods in both effectiveness and efficiency. We also evaluated the ability of the RSC results to serve for downstream 3D analysis, such as visual odometry and structure-from-motion, which verifies preference for the output of our algorithm over other existing RSC methods.

Can golfers choose low-risk routes in steep putting based on visual feedback of ball trajectory?

This study aims to clarify why the aiming method in golf putting in risky situations differs based on skill level. This study set up a difficult challenge (steep slopes and fast ball rolling greens), which required even professional golfers to change their aim. A total of 12 tour professionals and 12 intermediate amateurs were asked to perform a steep-slope task with no visual feedback of outcomes (no FB) followed by a task with visual feedback (with FB). The aim of the task was for the ball to enter the hole in one shot. Additionally, the participants were told that if the ball did not enter the hole, it was to at least stop as close to it as possible. The participant's aim (as an angle) and the kinematics of the putter head and ball were measured. The results indicated that professionals' highest ball trajectory points were significantly higher than that of amateurs, especially with FB. Additionally, professionals had higher ball-launch angles (the direction of the ball when the line connecting the ball and the center of the hole is 0 degrees) and lower peak putter head velocities than amateurs. Furthermore, the aim angle, indicating the golfer's decision-making, was higher for professionals under both conditions. However, even with FB, the amateurs' aim angles were lower and the difference between trials was smaller than that of professionals. Therefore, this study confirmed that the professionals made more drastic changes to their aim to find low-risk routes than the amateurs and that the amateurs' ability to adjust their aim was lower than that of professionals. The results suggest that the reason for the amateurs' inability to find low-risk routes lies in their decision-making. The professionals found better routes; however, there were individual differences in their routes.

Heat rolling as a post-treatment technique to enhance the integrity of electrospun nanofibrous membranes

Membranes fabricated based on electrospinning inherently allow for high porosity and large effective surface area but are physically weak and unstable. In this study, heat rolling was performed with different speed and various temperatures to improve the mechanical properties of electrospun nanofibrous membranes (ENMs). Although nanofibers did not fuse with each other tightly like those seen after other heat-based post-treatments, the ENMs after heat rolling were suitable to be used as filters for water treatment because of enhanced tensile strength and integrity. While the tensile strength of ENM without heat rolling was 0.95 MPa, the mechanical strength of ENMs increased from 1.57 MPa to 2.21 MPa depending on temperature at a fast heat rolling of 4.3 cm/s. As for a slow heat rolling of 1.25 cm/s, the mechanical properties were further improved and showed a value of 2.51 MPa at the temperature of 150 °C. Moreover, the foulants on the surface of the ENMs were detached by physical cleaning compared to commercial membranes based on the phase-inversion method.

Understanding the bending behavior and through-thickness strain distribution during asymmetrical rolling of high-strength aluminium alloy plates

The asymmetric rolling (ASR) process is highly desired to improve the through-thickness deformation/strain uniformity by introducing additional shear strains for uniform through-thickness microstructures and mechanical properties of metallic/alloy plates. In this study, the bending behavior and mechanism during the ASR processing of high-strength AA7050 aluminium alloy plates were simulated along with rolling trials. It shows that the plate will bend upward (toward slower roll) at larger speed ratios and smaller thickness reductions but downward (toward faster roll) at smaller speed ratios and larger thickness reductions. The ASR processing can increase the central equivalent plastic strains and decrease the surface-to-center strain gradient compared with that caused by the conventional symmetric rolling. The high strain rate bands (HSRBs) as key plastic strain accumulation regions are intimately connected with the post-rolling equivalent plastic strain distribution and the outgoing curvature. Especially, when the HSRB approaches the plate upper surface near the end of the deformation zone, normally at larger thickness reductions, a downward bending occurs despite that the lower roll rotates faster, and vice versa. The through-thickness HSRB induced by the ASR processing is considered to mainly enhancing the equivalent plastic strain homogeneity. The formation and interactive mechanisms of the HSRBs and their connection with the bending behavior during the ASR processing were discussed.

Simple and Fast Rolling Circle Amplification-Based Detection of Topoisomerase 1 Activity in Crude Biological Samples.

Isothermal amplification-based techniques such as the rolling circle amplification have been successfully employed for the detection of nucleic acids, protein amounts, or other relevant molecules. These methods have shown to be substantial alternatives to PCR or ELISA for clinical and research applications. Moreover, the detection of protein amount (by Western blot or immunohistochemistry) is often insufficient to provide information for cancer diagnosis, whereas the measurement of enzyme activity represents a valuable biomarker. Measurement of enzyme activity also allows for the diagnosis and potential treatment of pathogen-borne diseases. In all eukaryotes, topoisomerases are the key DNA-binding enzymes involved in the control of the DNA topological state during important cellular processes and are among the important biomarkers for cancer prognosis and treatment. Over the years, topoisomerases have been substantially investigated as a potential target of antiparasitic and anticancer drugs with libraries of natural and synthetic small-molecule compounds that are investigated every year. Here, the rolling circle amplification method, termed rolling circle enhanced enzyme activity detection (REEAD) assay that allows for the quantitative measurement of topoisomerase 1 (TOP1) activity in a simple, fast, and gel-free manner is presented.By cleaving and ligating a specially designed DNA substrate, TOP1 converts a DNA oligonucleotide into a closed circle, which becomes the template for rolling circle amplification, yielding ~103 tandem repeat rolling circle products. Depending on the nucleotide incorporation during the amplification, there is the possibility of different readout methods, from fluorescence to chemiluminescence to colorimetric. As each TOP1-mediated cleavage-ligation generates one closed DNA circle, the assay is highly sensitive and directly quantitative.