Cycle Solutions Research Articles

A novel process for simultaneously improving the strength and plasticity of 18Ni(350) maraging steel

A novel process involving cold deformation, cyclic solution, and two-step aging is developed for simultaneously improving the strength and plasticity of 18Ni(350) maraging steel. The strengthening and toughening mechanisms are elucidated by microstructural characterization and tensile property measurements. Cold deformation and cyclic solution refine the final martensite grains. In addition, two-step aging ensures the formation of numerous fine precipitates and a small amount of fine reversed austenite. Ultra-high strength is achieved by a combination of solid-solution, grain refinement, dislocation, and precipitation strengthening, with the latter having the largest contribution. Compared with the traditional process, the UTS and elongation are increased by 9.13% and 22.83%, respectively, to 2511 MPa and 5.81%, demonstrating the effectiveness of this novel process.

A Computer Simulation Study on Deposition Patterns of Cyclic Diblock Copolymer Solution Nanodroplets: Influence of Polymer Length and Concentration

A Computer Simulation Study on Deposition Patterns of Cyclic Diblock Copolymer Solution Nanodroplets: Influence of Polymer Length and Concentration

Use of Electropolishing in Orthodontic Appliances: An Option to Reduce the Risk of Metal Hypersensitivity.

Electropolishing is a common treatment in the industry; however, how it behaves in the mouth and what benefits it can bring over metal dental attachments have not yet been established. Thus, the aim of this study was to determine the levels of corrosion, the released metal ions, and the changes in structural composition in metallic orthodontic appliances following electropolishing treatment. This study included 56 orthodontic brackets and 28 archwires. The samples were subjected to a pH cycle to simulate an oral environment. Using UV-Vis spectrophotometry, the release of metallic particles was evaluated, and using scanning electron microscopy, the structural and composition changes were evaluated. Groups were compared using Student's t-tests with a value of p ≤ 0.05. The cyclical pH solutions showed variations between groups and days (1, 3, 5, 7 and 15), reaching the highest acidification in the self-ligating brackets; the absorbance between solutions did not differ significantly. As seen from the SEM results, the experimental group showed minor irregularities compared with the control groups. The experimental brackets decreased in iron and increased in chromium after electropolishing, while for the NiTi archwires, they decreased in nickel. Therefore, electropolishing treatments in metallic orthodontic attachments improve their surface structure and corrosion resistance could reduce the risk of metal hypersensitivity, mainly from nickel.

Semiclassical dynamics of a superconducting circuit: chaotic dynamics and fractal attractors

We study here the semiclassical dynamics of a superconducting circuit constituted by two Josephson junctions in series, in the presence of a voltage bias. We derive the equations of motion for the circuit through a Hamiltonian description of the problem, considering the voltage sources as semi-holonomic constraints. We find that the dynamics of the system corresponds to that of a planar rotor with an oscillating pivot. We show that the system exhibits a rich dynamical behaviour with chaotic properties and we present a topological classification of the cyclic solutions, providing insight into the fractal nature of the dynamical attractors.

Deposition Patterns Induced by the Evaporation of the Cyclic Diblock Copolymer Solution Droplet

Deposition Patterns Induced by the Evaporation of the Cyclic Diblock Copolymer Solution Droplet

Dirac exciton-polariton condensates in photonic crystal gratings.

Bound states in the continuum have recently been utilized in photonic crystal gratings to achieve strong coupling and ultralow threshold condensation of exciton-polariton quasiparticles with atypical Dirac-like features in their dispersion relation. Here, we develop the single- and many-body theory of these new effective relativistic polaritonic modes and describe their mean-field condensation dynamics facilitated by the interplay between protection from the radiative continuum and negative-mass optical trapping. Our theory accounts for tunable grating parameters giving full control over the diffractive coupling properties between guided polaritons and the radiative continuum, unexplored for polariton condensates. In particular, we discover stable cyclical condensate solutions mimicking a driven-dissipative analog of the zitterbewegung effect characterized by coherent superposition of ballistic and trapped polariton waves. We clarify important distinctions between the polariton nearfield and farfield explaining recent experiments on the emission characteristics of these long lived nonlinear Dirac polaritons.

A Natural Approach to Solving the Traveling Salesman Problem

Introduction. The traveling salesman problem is a transport-type problem. It is natural to use a method based on the technology for solving transport problems to solve it. The cyclicity and degeneracy of the solution to the traveling salesman problem requires significant modification of the corresponding stages of solving the transport problem (drawing up an initial feasible solution; checking the plan for optimality; obtaining a new feasible solution). Purpose. Development of a natural approach to solving the traveling salesman problem. Description of the structure of a set of traveling salesman problems that have a predetermined optimal solution. Algorithmic formation of such problems for the purpose of conducting mass computing experiments. Results. The paper presents new results and computational experiments with a developed natural algorithm for solving the traveling salesman problem, based on the technology for solving transport problems, including a new effective method for generating an initial cyclic solution, an algorithm for transitioning from the initial cyclic to another, also cyclic, solution. An algorithm has been developed for constructing the traveling salesman problem with an optimal solution given in advance, which allows for a better understanding of the structure of traveling salesman problems. Conclusions. The results of computational experiments show that the use of potentials method technology for solving the traveling salesman problem, as a special transport problem, is a promising direction for searching for a high-quality solution. The developed algorithms and programs expand the possibilities of solving the traveling salesman problem. The time it takes to solve a problem depends significantly on the size of the problem. In this regard, it is essential to automatically generate the traveling salesman problem with a given optimal solution, which allows you to conduct mass experiments and draw conclusions. Keywords: travelling salesman problem, method of potentials, optimality criterion, cyclic substitution, route, algorithm.

Phase transition in von Neumann entropy from replica symmetry breaking

We study the entanglement transition in monitored Brownian SYK chains in the large-N limit. Without measurement the steady state n-th Rényi entropy is obtained by summing over a class of solutions, and is found to saturate to the Page value in the n → 1 limit. In the presence of measurements, the analytical continuation n → 1 is performed using the cyclic symmetric solution. The result shows that as the monitoring rate increases, a continuous von Neumann entanglement entropy transition from volume-law to area-law occurs at the point of replica symmetry unbreaking.

On the Z5.8‐dependence of viscosity of polymer rings over the range 15 < Zw ≤ 300 of the entanglement number

AbstractDynamic moduli G* and zero‐shear viscosity ηo,ring data in both melt and solution states were reported for putative cyclic poly(3,6‐dioxa‐1,8‐octanedithiol) (RDODT) with molecular weights ranging from 43 to 556 kg/mol. Measurements over wide temperature ranges provide up to 18 decades of reduced frequency to characterize RDODT melts and solutions with Zw = Mw/Me,lin from 23 to 300, where Mw is the weight average molecular weight and Me,lin ≈ 1850 g/mol is the entanglement molecular weight of the linear counterparts (LDODT). The G* of all the seven RDODT melts and eight of their solutions with Zw > 15 all have a rubbery plateau with the plateau moduli about same as GNo of the corresponding LDODT. The value Zw ≈ 15 marks the threshold for the change in scaling of ηo,ring from the Rouse‐like ηo,ring ∼ Zw1.0 to a much stronger dependence of ηo,ring ∼ Zw5.8 for Zw up to 300. Such a Zw5.8‐dependence has not been seen before in cyclic polymers and cannot be accounted for by current theoretical models for cyclic polymers. The Coupling Model had been used before to explain the Mw3.4 ‐dependence of linear entangled polymers and the stronger Mw ‐dependence of multi‐arm star branched polymers. It is applied to cyclic RDODT melts and solutions and the results provide an explanation of the observed Zw5.8‐dependence of ηo,ring.

Silica-Based Stationary Phase with Surface Bound N-Acetyl-glucosamine for Hydrophilic Interaction Liquid Chromatography.

A hydrophilic silica-based stationary phase with surface bound N-acetylglucosamine (GlcNAc-silica) was prepared in house and characterized physically via Fourier transform infrared (FTIR) analysis and thermogravimetric analysis (TGA) and chromatographically over a wide range of mobile phase compositions. While both FTIR and TGA confirmed the attachment of the GlcNAc ligands to the silica surface, the chromatographic evaluation of GlcNAc-silica with polar and slightly polar standard solutes (e.g., sugars, nucleic acid fragments, phenolic, and benzoic acid derivatives) yielded the typical hydrophilic interaction liquid chromatography (HILIC) behaviors in the sense that retention increased with increases in solute polarity and the organic content (i.e., acetonitrile) of the hydro-organic mobile phase (i.e., ACN-rich mobile phase). Sugars derivatized with 1-naphthylamine (1-NA) and 2-aminoanthrcene (2-AA) such as xylose, glucose, and short chains maltooligosaccharides constituted the most polar species for HILIC retention evaluation, and in addition, the maltooligosaccharides offered a polar homologous series for gauging the hydrophilicity of GlcNAc-silica in analogy with alkylbenzene homologous series and other nonpolar homologues for evaluating the hydrophobicity of non-polar stationary phases. On the other hand, the benzoic acid and phenolic acid derivatives were the probe solutes for evaluating the HILIC retention dependence of ionizable solutes on the pH of the mobile phase. Similarly, the nucleobase and nucleoside weak basic solutes as well as some typical cyclic nucleotide acidic solutes allowed for the examination of the dependence of solute retention on the pH of the mobile as well as the polarity of the species.

Algorithm for Constructing the Traveling Salesman Problem with a Given Optimal Solution

Issues related to the solution of the traveling salesman problem are considered. An algorithm for constructing the traveling salesman problem with a predetermined optimal cyclic solution has been developed. The algorithm can be used to evaluate the effectiveness of methods for solving the traveling salesman problem, to determine the optimality of a feasible solution found in some way, and also to understand the structure of problems with a given cyclic optimal solution.

Resource saving based dwell time allocation and detection threshold optimization in an asynchronous distributed phased array radar network

The resource optimization plays an important role in an asynchronous Phased Array Radar Network (PARN) tracking multiple targets with Measurement Origin Uncertainty (MOU), i.e., considering the false alarms and missed detections. A Joint Dwell Time Allocation and Detection Threshold Optimization (JDTADTO) strategy is proposed for resource saving in this case. The Predicted Conditional Cramér-Rao Lower Bound (PC-CRLB) with Bayesian Detector and Amplitude Information (BD-AI) is derived and adopted as the tracking performance metric. The optimization model is formulated as minimizing the difference between the PC-CRLBs and the tracking precision thresholds under the constraints of upper and lower bounds of dwell time and false alarm ratio. It is shown that the objective function is nonconvex due to the Information Reduction Factor (IRF) brought by the MOU. A cyclic minimizer-based solution is proposed for problem solving. Simulation results confirm the flexibility and robustness of the JDTADTO strategy in both sufficient and insufficient resource scenarios. The results also reveal the effectiveness of the proposed strategy compared with the strategies adopting the BD without detection threshold optimization and amplitude information.

Dynamics of a linearly perturbed May-Leonard competition model.

The May-Leonard model was introduced to examine the behavior of three competing populations where rich dynamics, such as limit cycles and nonperiodic cyclic solutions, arise. In this work, we perturb the system by adding the capability of global mutations, allowing one species to evolve to the other two in a linear manner. We find that for small mutation rates, the perturbed system not only retains some of the dynamics seen in the classical model, such as the three-species equal-population equilibrium bifurcating to a limit cycle, but also exhibits new behavior. For instance, we capture curves of fold bifurcations where pairs of equilibria emerge and then coalesce. As a result, we uncover parameter regimes with new types of stable fixed points that are distinct from the single- and dual-population equilibria characteristic of the original model. On the contrary, the linearly perturbed system fails to maintain heteroclinic connections that exist in the original system. In short, a linear perturbation proves to be significant enough to substantially influence the dynamics, even with small mutation rates.

Modelling solution structures of cyclic peptides - How good are we?

Cyclic peptides (CPs) are macrocycles made from amino acids that can bind to classically undruggable drug targets. Controlling pharmacokinetic properties of these macrocyclic peptides is an open question, limited by having precise knowledge of the underlying solution structures. CP solution dynamics are complex: individual structures are often separated by large energy barriers; the presence of conformers is environment dependent and solution conformers can be different from bioactive structures. Specialised simulation methods for CPs have previously been designed to reproduce available x-ray structures, but it is often unknown how well solution structures are reproduced. Here, we report the largest cyclic peptide solution NMR dataset “MacroConf”, which we built from existing literature. We use a range of molecular dynamics methods and specialised cheminformatics methods to model the solution structures of over 30 cyclic peptides from this dataset. We explore (a) how different methods perform relative to one another and to the experimental reference structures and (b) whether computationally cheaper methods can reach the accuracy of gold-standard accelerated molecular dynamics simulations to allow for fast prediction of solution ensembles. By providing automated computational workflows, this work is easily extendable, fully reproducible, and is built as a reference point to guide development of future conformer generators for cyclic peptides.

Observing Nonpreferential Absorption of Linear and Cyclic Carbonate on the Silicon Electrode.

Silicon is reported to be a promising anode material due to its high storage capacity and excellent energy conversion rate. Molecular-level insight into the interaction between silicon electrodes and electrolyte solutions is essential for understanding the formation of a stable solid electrolyte interphase (SEI), but it is yet to be explored. In this study, we apply femtosecond sum frequency generation vibrational spectroscopy to investigate the initial adsorption of various pure and mixed electrolyte molecules on the silicon anode surface by monitoring the SFG signals from the carbonyl group of electrolyte molecules. When the silicon comes in contact with a pure carbonate solution, the linear carbonates of diethyl carbonate and ethyl methyl carbonate adopt two conformations with opposite C═O orientations on the silicon interface while the cyclic carbonates of ethylene carbonate and propylene carbonate almost adopt one conformation with C═O bonds pointing toward the silicon electrode. When the silicon comes in contact with the mixed linear and cyclic carbonate solutions, the total SFG intensity from the mixed solutions is approximately 2∼5 times weaker than those of pure cyclic carbonates. The C═O bonds of cyclic carbonates point toward the silicon electrode, while the C═O bonds of linear carbonates face toward the bulk solution at the silicon/mixed solution interface. No preferential absorption behaviors of the linear and cyclic carbonate electrolytes on the silicon electrode are observed. Such findings may help to understand the mechanism by which the SEI formed on the silicon anode is unstable.

Cyclic Solution and Optimal Approximation of the Quaternion Stein Equation

Cyclic Solution and Optimal Approximation of the Quaternion Stein Equation

MacroConf – dataset & workflows to assess cyclic peptide solution structures

We introduce the MacroConf dataset, a collection of cyclic peptide solution structures. The dataset was used to benchmark the performance of molecular dynamics and cheminformatics-based conformer generators.

BTEXS Removal From Aqueous Phase by MCM-41 Green Synthesis Using Rice Husk Silica

Large volumes of contaminated industrial wastewater have caused growing concern among researchers and environmentalists. Benzene, toluene, ethylbenzene, xylene, and styrene (BTEXS) cyclic hydrocarbons in industrial effluents are often completely stable to biodegradation and must be treated before disposal. In this context, using adsorption processes is a potential alternative for treating a wide range of organic pollutants, especially aromatic compounds in industrial wastewater. This study investigated the preparation of MCM-41 from silica; extracted from rice husk ash; MCM-41 was green synthesized to evaluate the effect of mesoporous used in BTEXS removal of an aqueous medium using the Taguchi method. The aqueous solution contains cyclic hydrocarbons was synthetically prepred based on real industrial effluent in concentrations of 50, 100, and 150 mg/l using MCM-41 catalysts, in doses of 0.1, 0.5, and 1g, at different pH values. In the present study, the optimum results obtained by Taguchi method analysis were pH =11, for duration of 60 minutes, the concentration of cyclic hydrocarbon solution BTEXS 100 mg/l, and nanoparticle dose of 0.5 g. The maximum BTEXS removal of 77.36% was achieved by the use of hydrogen peroxide.

Nonlocal de Sitter gravity and its exact cosmological solutions

This paper is devoted to a simple nonlocal de Sitter gravity model and its exact vacuum cosmological solutions. In the Einstein-Hilbert action with Λ term, we introduce nonlocality by the following way: R-2Lambda =sqrt{R-2Lambda}kern1em sqrt{R-2Lambda}to sqrt{R-2Lambda}kern1em Fleft(square right)kern1em sqrt{R-2Lambda} , where Fleft(square right)=1+{sum}_{n=1}^{+infty}left({f}_n{square}^n+{f}_{-n}{square}^{-n}right) is an analytic function of the d’Alembert-Beltrami operator □ and its inverse □−1. By this way, R and Λ enter with the same form into nonlocal version as they are in the local one, and nonlocal operator F(□) is dimensionless. The corresponding equations of motion for gravitational field gμν are presented. The first step in finding some exact cosmological solutions is solving the equation square sqrt{R-2Lambda}=qsqrt{R-2Lambda} , where q = ζΛ (ζ ∈ R) is an eigenvalue and sqrt{R-2Lambda} is an eigenfunction of the operator □. We presented and discussed several exact cosmological solutions for homogeneous and isotropic universe. One of these solutions mimics effects that are usually assigned to dark matter and dark energy. Some other solutions are examples of the nonsingular bounce ones in flat, closed and open universe. There are also singular and cyclic solutions. All these cosmological solutions are a result of nonlocality and do not exist in the local de Sitter case.

Exploring sparse graphs with advice

Graph exploration is a theoretical model of the crucial task of moving an agent through an unknown environment. Here, an algorithm has to guide an explorer through a network with n vertices and m edges, visiting every vertex at least once. We consider the fixed-graph scenario by Kalyanasundaram and Pruhs (ICALP, 1993), where the explorer sees all vertices reachable in one step, their unique names and their distance from the current position.The algorithm only learns the structure of the graph during computation. Therefore, we are interested in the amount of crucial a-priori information (the advice complexity) needed to solve the problem optimally.We look at graph exploration on directed graphs and focus on cyclic solutions. It is known that O(nlog⁡n) bits of advice are necessary and sufficient to compute an optimal solution for general graphs. We present algorithms with O(m) advice, thus improving the bound for sparse graphs.