Cyclic Phenomena Research Articles

Singular secular Kuznets-like period realized amid industrial transformation in US FDA medical devices: a perspective on growth from 1976 to 2020

ABSTRACT Introduction Since inception, the United States (US) Food and Drug Administration (FDA) has kept a robust record of regulated medical devices (MDs). Based on these data, can we gain insight into the innovation dynamics of the industry, including the potential for industrial transformation?. Areas Covered Using premarket notifications (PMNs) and approvals (PMAs) data, it is shown that from 1976 to 2020 the total composite (PMN+PMA) metric follows a single secular period: 20.5 years (applications – peak-to-peak: 1992–2012; trough: 2002) and 26.5 years (registrations – peak-to-peak: 1992–2019; trough: 2003), with a peak-to-trough relative percentage difference of 24% and 28%, respectively. Importantly, PMNs and PMAs independently present as an inverse structure. Expert Opinion The evidence suggests that MD innovation is driven by a singular secular Kuznets-like cyclic phenomenon (independent of economic crises) derived from a fundamental shift from simple (PMNs) to complex (PMAs) MDs. Portentously, while the COVID-19 crisis may not affect the overriding dynamic, the anticipated yet significant (~25%) MD innovation drop may be potentially attenuated with attentive measures by MD stakeholders. Limitations of this approach and further thoughts complete this perspective.

Relation of nonlinear oscillator design based on phase reduction method and fractional derivative

SummaryFor wide application of the synchronization properties of nonlinear oscillators in control and signal processing engineering field, a common design method for nonlinear oscillator models is required. The output response of a nonlinear oscillator excited by a periodic signal implicitly includes information on both the instantaneous phase and the amplitude of the input signal. The design of a nonlinear oscillator model that can synchronize with an arbitrary cyclic phenomenon can be enabled by explicitly expressing the dynamics of both phase and amplitude with the phase reduction method and organizing them by the number of events in one period. Assuming the cyclic phenomenon to be a single periodic signal, the properties of the generalized nonlinear oscillator model depend on the phase resolution of the signal, which is associated with the phase‐shift of fractional calculus. Thus, this study verifies the validity of fractional calculus through the input‐output characteristic of the generalized nonlinear oscillator model. Numerical simulation using a fractional differentiator with backward‐difference demonstrated that increasing the phase resolution of a single periodic signal improves the estimation accuracy of the phase and amplitude of the signal by employing a generalized nonlinear oscillator model.

Cyclic response of fibre reinforced dense sand

Fibre reinforcement has proven to be an adequate technical solution for soil improvement where its applications include slopes, railways, highways and, more recently, wind turbines foundations or any structure subjected to the effect of cyclic loads. A few studies have investigated the cyclic behaviour of fibre reinforced soils, and they mostly focus on loose materials and liquefaction. In this sense, this study investigated the cyclic behaviour of a fibre reinforced dense sand under undrained triaxial conditions. Drained and undrained monotonic and undrained cyclic triaxial tests were performed with varying initial effective stresses (20 to 200 kPa) and cyclic stress ratios (0.1 to 0.5). The soil, a uniform fine sand, was reinforced with 50 mm long polypropylene fibres and compacted to a dense state (Dr = 90%). Fibres contribution, as expected, improved sand monotonic behaviour under compression with material’s strength parameters shifting from ϕ = 39.8° and c’ = 0 kPa to ϕ = 53.5° and c’ = 0 kPa, under drained conditions, and from ϕ = 37.2° and c’ = 0 kPa to ϕ = 43.9° and c’ = 41.6 kPa, under undrained conditions. Accordingly, under cyclic loading conditions fibres also enhanced mixtures strength which is depicted by the increase of cycles until failure and a meaningful reduction of both cyclic and permanent pore water pressures development. Also, in spite of reinforcement inclusion or not, dense specimens experienced the cyclic mobility phenomena at failure, namely, samples were able to withstand loading cycles even after great mean effective stress reduction. Fibres inclusion turned dense sand specimens stiffer than the unreinforced ones when subjected to cyclic loads. Finally, the application of a constitutive model was investigated to predict the fibre-reinforced dense material behaviour. The applied model was not capable of predicting the behaviour of the investigated fibre-reinforced dense sand under the whole range of studied variables. The response for higher CSR values was better captured by the model.

Modelling Study of Cycle-To-Cycle Variations (CCV) in Spark Ignition (SI)-Controlled Auto-Ignition (CAI) Hybrid Combustion Engine by Using Reynolds-Averaged Navier–Stokes (RANS) and Large Eddy Simulation (LES)

The spark ignition (SI)-controlled auto-ignition (CAI) hybrid combustion is characterized by early flame propagation combustion and subsequent auto-ignition combustion. The application of combined SI–CAI hybrid combustion can be used to effectively extend the operating range of CAI combustion and achieve smooth transitions between SI and CAI combustion modes. However, SI–CAI hybrid combustion can produce significant cycle-to-cycle variations (CCV). In order to better understand the sources of CCV and minimize its occurrence, the large eddy simulation (LES) and Reynolds-averaged Navier–Stokes (RANS) approaches were employed in this study to model and understand the cyclic phenomenon of SI–CAI hybrid combustion. Both the multi-cycle LES and RANS simulations were analyzed against the experimental measurements in a single cylinder engine at 1500 rpm and a 5.43 bar average indicated the mean effective pressure (IMEP). The detailed analysis of the in-cylinder pressure traces, IMEP, in-cylinder peak pressure (PP), peak pressure rise rate (PPRR) and the crank angles with fuel mass burned fraction at 10%, 50%, 90% and mode transition was performed. The results indicate that overall, the adopted LES simulations could effectively predict the cyclic variations in the hybrid combustion observed in the experiments, while the RANS simulations failed to reproduce the cyclic characteristics at the chosen engine operating conditions. Based on the LES results, the correlation and visualization studies indicate that the cyclic variations in the local velocity around the spark plug lead to the variations in the early flame propagation, which in turn produce temperature fluctuations among the cycles and result in greater variations in the subsequent auto-ignition combustion events.

Epsilon-Diskcyclic Operators

<p style="text-align: justify;">In this paper, we will introduce a new concept of cyclic phenomena that is called "-diskcyclic operator and construct <p style="text-align: justify;">examples to show the relationship between other types. In particular, for each " in (0, 1), we will construct an "-diskcyclic <p style="text-align: justify;">operator that is not diskcyclic. These examples illustrate the main differences between the new definition and other types.

Nonlinear oscillator design based on phase reduction method for closed‐loop system

SummaryTo widely utilize the synchronization properties of nonlinear oscillators in the control and signal processing engineering field, a common design method for a nonlinear oscillator model would be helpful. The output response of a nonlinear oscillator excited by a periodic signal implicitly includes the information of both the instantaneous phase and the amplitude of the input signal. Explicitly expressing the dynamics of both phase and amplitude with the phase reduction method, and organizing them by the number of events in one period, could enable the design of a nonlinear oscillator model in the same manner that can synchronize with an arbitrary cyclic phenomenon in a broad sense. Assuming the cyclic phenomenon is a single periodic signal, the property of the generalized nonlinear oscillator model has the role as a common‐dimensional observer to attain the pseudo‐property of both iso‐damping and flat‐gain. Thus, this article determines the essential role of the nonlinear oscillator inserted in the closed‐loop system through investigating the input–output characteristic of the generalized nonlinear oscillator model. As a result of the numerical simulation using a simple vibration excitation and suppression system, it was found that using the generalized nonlinear oscillator model enables us to easily build the closed‐loop system including the pseudo‐property of both iso‐damping and flat‐gain.

A feedback mechanism between crystals and bubbles in a RuO2-bearing melt

Crystals are known to affect bubble behavior in natural and industrial melts. In volcanology, high crystal contents (ϕc > 30 vol.%) may drastically increase the suspension viscosity, altering bubble dynamics severely enough to modify eruptive style. During industrial glass production, crystals can affect the process and the final product. In this work, we investigate how a small crystallinity of nano-sized RuO2 (ϕc ∼ 2 vol.%) modifies bubble behavior in a melt, generating a cyclic gas-release phenomenon. We conduct a series of experiments on a three-phase system composed of a borosilicate melt, bubbles, and RuO2 crystals. Optical microscopic investigation is performed on the products of thermal treatment at 1000°C for different durations. Based on viscosity measurements, contact angle measurements, and numerical simulations, we propose a mechanism of entrainment of bubbles carrying crystals to the upper surface accompanied by crystal aggregation, and followed by an increase in viscosity to explain the observed phenomenon.

A study of pain perception by cold pressure test in young females during the different phases of menstrual cycle

Background: Menstruation is a cyclic physiological phenomenon showing fluctuations of various Gonadal hormones. Gonadal hormones (estrogen and progesterone) influences pain sensitivity, the former strongly influences nociceptive actions; whereas the latter prevents neuropathic pain some previous study has shown changes in pain sensitivity during menstruation. However, there is only little evidence present on effect of Gonadal hormones on experimental pain Sensitivity. Aims and Objectives: The aim of the present study is to differentiate in Sensation of pain stimulus in terms of - pain threshold, pain tolerance, pain intensity, pain unpleasantness in females with normal menstruation during different phases through using cold presser test. Materials and Methods: A total of 55 normal healthy females were enrolled in the study as per the eligibility criteria. Cold presser test was used as a pain stimulus source. The participants were instructed to hold their least dominant hand in the water bath as long as possible and were requested to inform the first sensation of pain which denoted the participants’ pain threshold. Time from pain threshold to the point where participants could no longer cope with pain and indicate stop, was recorded as pain tolerance. At this point, participants were directed to note pain intensity and unpleasantness on the visual analogue scale. Results: The results showed that high significant pain intensity, pain unpleasantness, and pain tolerance level were highly significant during follicular phase than luteal phase. Conclusion: In our study, we concluded pain perception difference across during different phase of menstruation in the form of high significant pain intensity, pain unpleasantness, and pain tolerance during follicular phase due to the hormonal fluctuation and the differences in autonomic nervous system reactivity these would be the underlying mechanism for these findings.

Refined Catalan and Narayana cyclic sieving

We prove several new instances of the cyclic sieving phenomenon (CSP) on Catalan objects of type \(A\) and type \(B\). Moreover, we refine many of the known instances of the CSP on Catalan objects. For example, we consider triangulations refined by the number of "ears", non-crossing matchings with a fixed number of short edges, and non-crossing configurations with a fixed number of loops and edges.Keywords: Dyck paths, cyclic sieving, Narayana numbers, major index, q-analog.Mathematics Subject Classifications: 05E18, 05A19, 05A30

Macdonald polynomials and cyclic sieving

The Garsia–Haiman module is a bigraded Sn-module whose Frobenius image is a Macdonald polynomial. The method of orbit harmonics promotes an Sn-set X to a graded polynomial ring. The orbit harmonics can be applied to prove cyclic sieving phenomena which is a notion that encapsulates the fixed-point structure of finite cyclic group action on a finite set. By applying this idea to the Garsia–Haiman module, we provide cyclic sieving results regarding the enumeration of matrices that are invariant under certain cyclic row and column rotation and translation of entries.

850℃ 고온에서 Alloy 800H 모재와 용접재의 저사이클 피로 거동

Alloy 800H is one of the candidate materials for key structural components such as control rod systems, hot gas duct, core barrels, core supports and shut-down cooling systems for the very high temperature reactor (VHTR) system. The aim of this paper is to compare the low-cycle fatigue behaviors of the alloy 800H base metal and weldments at a high temperature of 850℃. Low cycle fatigue tests were carried out for four different total strain ranges of 0.6, 0.9, 1.2 and 1.5% under constant strain rate of 10-3/s. In all test conditions, the fatigue life of base metal and weldments decreased inversely proportional to the total strain range. The cyclic stress response behavior showed cyclic softening phenomenon for both materials. The low cycle fatigue life for base metal and weldments were predicted by the Coffin-Manson-Basquin law. The results showed that transition life of the weldments is shorter than that of the base metal.

Dihedral sieving on cluster complexes

The cyclic sieving phenomenon of Reiner, Stanton, and White characterizes the stabilizers of cyclic group actions on finite sets using q-analogue polynomials. Eu and Fu demonstrated a cyclic sieving phenomenon on generalized cluster complexes of every type using the q-Catalan numbers. In this paper, we exhibit the dihedral sieving phenomenon, introduced for odd n by Rao and Suk, on clusters of every type. In the type A case, we show that the Raney numbers count both reflection-symmetric k-angulations of an n-gon and a particular evaluation of the (q,t)-Fuss--Catalan numbers. We also introduce a sieving phenomenon for the symmetric group, and discuss possibilities for dihedral sieving for even n.

Cyclic behaviour of certain operators on the disc algebra

We present results concerning the cyclic behaviour of weighted shifts and composition operators on the disc algebra. Most of our proofs use the representations of the dual space of the disc algebra as Banach spaces of analytic functions on the unit disc. Taking into account that no composition operator on the disc algebra can be hypercyclic, the results we obtain show that the composition operators induced by linear fractional maps with an interior fixed points have the same cyclic behaviour on the disc algebra as they do on the Hardy space , as described in Bourdon and Shapiro [Cyclic phenomena for composition operators. Mem Am Math Soc. 1997;125(596)], while the operators induced by linear fractional maps with boundary fixed points have the same cyclic behaviour on the disc algebra as they do on the Dirichlet space, as described in Gallardo-Gutiérrez and Montes-Rodríguez [The role of the spectrum in the cyclic behavior of composition operators. Mem Am Math Soc. 2004;167(791)].

The Relationship between Cyclic Multi-Scale Self-Organized Processes and Wear-Induced Surface Phenomena under Severe Tribological Conditions Associated with Buildup Edge Formation

This paper presents experimental investigations of various interrelated multi-scale cyclic and temporal processes that occur on the frictional surface under severe tribological conditions during cutting with buildup edge formation. The results of the finite element modeling of the stress/temperature profiles on the friction surface are laid out. This study was performed on a multilayer coating with the top alumina ceramic layer deposited by CVD (chemical vapor deposition) on a WC/Co carbide substrate. A detailed analysis of the wear process was conducted by 3D wear evaluation, scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS) and electron backscattered diffraction (EBSD), as well as X-ray photoelectron spectroscopy (XPS) methods. The following cyclic phenomena were observed on the surface of the tribo-system during the experiments: a repetitive formation and breakage of buildups (a self-organized critical process) and a periodical increase and decrease in the amount of thermal barrier tribo-films with a sapphire structure (which is a self-organization process). These two processes are interrelated with the accompanying progression of cratering, eventually resulting in the catastrophic failure of the entire tribo-system.

Micromechanical crystal plasticity back stress evolution within FCC dislocation substructure

Experiments and theories have suggested the evolution of intragranular back stress is primarily dependent on the characteristics and development of dislocation substructure in face-centered cubic (FCC) metals and alloys. Despite this, continuum modeling of complex cyclic loading phenomena such as inelastic ratchet strain accumulation typically appeals to one of several phenomenological back stress forms with weak connections to physical mechanisms. In the current work, a micromechanically-based back stress evolution law is derived and implemented in a crystal plasticity framework for FCC metals that directly considers the evolution of dislocation substructure. The model is used in a case study of stainless steel 316L (SS316L), and good agreement is found with experiments on single- and poly-crystalline specimens subjected to monotonic, fully-reversed cyclic loading, and stress-controlled cyclic loading with mean stress. Ratcheting is attributed to dislocation substructure formation, dissolution, and stabilization within this physically-based framework.

Cyclic sieving and orbit harmonics

Orbit harmonics is a tool in combinatorial representation theory which promotes the (ungraded) action of a linear group G on a finite set X to a graded action of G on a polynomial ring quotient by viewing X as a G-stable point locus in \({\mathbb {C}}^n\). The cyclic sieving phenomenon is a notion in enumerative combinatorics which encapsulates the fixed-point structure of the action of a finite cyclic group C on a finite set X in terms of root-of-unity evaluations of an auxiliary polynomial X(q). We apply orbit harmonics to prove cyclic sieving results.

Formula omitted]-dimensions of highest weight crystals and cyclic sieving phenomenon

In this paper, we compute explicitly the q-dimensions of highest weight crystals modulo qn−1 for a quantum group of arbitrary finite type under certain assumption, and interpret the modulo computations in terms of the cyclic sieving phenomenon. This interpretation gives an affirmative answer to the conjecture by Alexandersson and Amini. As an application, under the assumption that λ is a partition of length <m and there exists a fixed point in SSTm(λ) under the action c arising from the crystal structure, we show that the triple (SSTm(λ),〈c〉,sλ(1,q,q2,…,qm−1)) exhibits the cycle sieving phenomenon if and only if λ is of the form ((am)b), where either b=1 or m−1. Moreover, in this case, we give an explicit formula to compute the number of all orbits of size d for each divisor d of n.

Development of a novel method for the in-situ dechlorination of immovable iron elements: optimization of Cl\u2212 extraction yield through experimental design

The conservation of iron objects exposed to marine aerosol is threatened by the formation of akaganeite, a highly unstable Cl-bearing corrosion phase. As akaganeite formation is responsible of the exfoliation of the rust layer, chlorides trigger a cyclic alteration phenomenon that often ends with the total consumption of the iron core. To prevent this degradation process, movable iron elements (e.g. archaeometallurgical artefacts) are generally immersed in alkaline dechlorination baths. Aiming to transfer this successful method to the treatment of immovable iron objects, we propose the in-situ application of alkaline solutions through the use of highly absorbent wraps. As first step of this novel research line, the present work defines the best desalination solution to be used and optimizes its extraction yield. After literature review, a screening experimental design was performed to understand the single and synergic effects of common additives used for NaOH baths. Once the most effective variables were selected, an optimization design was carried out to determine the optimal conditions to be set during treatment. According to the experimental work here presented, the use of 0.7 M NaOH solutions applied at high temperatures (above 50 °C) is recommended. Indeed, these conditions enhance chloride extraction and iron leaching inhibition, while promoting corrosion stabilization.

Cyclic Sieving for cyclic codes

Prompted by a question of Jim Propp, this paper examines the cyclic sieving phenomenon (CSP) in certain cyclic codes. For example, it is shown that, among dual Hamming codes over Fq, the generating function for codedwords according to the major index statistic (resp. the inversion statistic) gives rise to a CSP when q=2 or q=3 (resp. when q=2). A byproduct is a curious characterization of the irreducible polynomials in F2[x] and F3[x] that are primitive.

Cyclic softening behavior of structural steel with strain range dependence

In seismic analysis, the cyclic performance of structural steel members is closely related to the strain range dependence effect. The strain range dependence effect has been extensively investigated from the perspective of hardening during the range expansion. However, the research on the cyclic softening behavior induced by the shrinkage of the loading range is insufficient, which corresponds to the scenario of the descending-magnitude long tail after the peak value in seismic analysis. In this study, eight cyclic coupon tests of Q345B structural steel are conducted to comprehensively investigate the strain range dependence effect experimentally at first. The test results indicate that the stress amplitudes experience loop-wise softening when the strain range drops to a lower level and gradually converge to a stabilized magnitude higher than the reference value obtained from constant-amplitude cases. Moreover, the cyclic softening is only influenced by the historical maximal loading range regardless of the intermediate loading history. For describing the experimental observations, a sophisticated constitutive model for general structural steel is proposed wherein a novel concept of incomplete collapse effect, which possesses a clear geometric interpretation, is specially designed to characterize the cyclic softening phenomena. Considering the future demand in multi-scale analysis, the constitutive model is implemented by inverse-P norm algorithm applicable to all spatial dimensions. A semi-automatic and efficient calibration method is developed to elude manually calibrating numerous entangled material parameters. Finally, the accuracy of the proposed constitutive model is validated by two batches of material-level coupon tests and a member-level experiment of two shear damper specimens, which demonstrates the capabilities of the proposed constitutive model in reasonably predicting the cyclic softening behavior with the strain range dependence as well as other hysteretic properties.