An alternative scheme for effective range corrections in pionless EFT

We discuss an alternative scheme for including effective range corrections in pionless effective field theory. The standard approach treats range terms as perturbative insertions in the T-matrix. In a finite volume this scheme can lead to singular behavior close to the unperturbed energies. We consider an alternative scheme that resums the effective range but expands the spurious pole of the T-matrix created by this resummation. We test this alternative expansion for several model potentials and observe good convergence.

Elastic Scattering of Slow Electrons by Noble Gases—The Effective Range Theory and the Rigid Sphere Model

We report on an extensive semi-empirical analysis of scattering cross-sections for electron elastic collision with noble gases via the Markov Chain Monte Carlo-Modified Effective Range Theory (MCMC−MERT). In this approach, the contribution of the long-range polarization potential (∼r−4) to the scattering phase shifts is precisely expressed, while the effect of the complex short-range interaction is modeled by simple quadratic expression (the so-called effective range expansion with several adjustable parameters). Additionally, we test a simple potential model of a rigid sphere combined with r−4 interaction. Both models, the MERT and the rigid sphere are based on the analytical properties of Mathieu functions, i.e., the solutions of radial Schrödinger equation with pure polarization potential. However, in contrast to MERT, the rigid sphere model depends entirely upon one adjustable parameter—the radius of a hard-core. The model’s validity is assessed by a comparative study against numerous experimental cross-sections and theoretical phase shifts. We show that this simple approach can successfully describe the electron elastic collisions with helium and neon for energies below 1 eV. The purpose of the present analysis is to give insight into the relations between the parameters of both models (that translate into the cross-sections in the very low energy range) and some “macroscopic” features of atoms such as the polarizability and atomic “radii”.

How a ball free to orbit in a circular track mitigates the galloping of a square prism

Transverse galloping is a type of flow-induced vibration (FIV) that leads to critical design considerations for engineering structures. A purely nonlinear energy sink (NES) composed of a ball free to rotate in a circular track experimentally mitigated the galloping of a square in a previous study. The current study introduces a model for simulating the dynamics of the square prism coupled with a ball-in-track (BIT) NES and predicting the system behaviour at high flow speeds beyond the limits of the previously presented experiments. Numerical simulations employ the fitting of experimental data as inputs to define parameters. Wind tunnel static experiments provide the galloping force coefficient [[EQUATION]] relative to the prism angle of attack. Additionally, free rotation tests allow evaluating the ball damping coefficient [[EQUATION]] as a function of its mass and the NES track radius. The result of the rotation tests provides a critical angular speed beyond which the ball damping increases non-linearly. We point out the damping variation as an advantage of the BIT-NES; less damping at low angular velocities helps the ball start its rotation, while relatively large damping at higher speeds dissipates more energy from the vibrating system. Numerical results exhibit four response modes for the NES; oscillatory at low flow speeds, intermittent within a small range of higher flow speeds, rotational at higher flow speeds, and ineffective regime at flow speeds out of the NES effective range. Modelling the primary mass as a parametric excitation source for the NES provides an analytical estimation of the boundary between the oscillatory and intermittent regimes. Furthermore, we advance an analytical analysis of the power flow across the integrated prism-NES system to explain the NES behaviour and predict the limit of its effective range.

Acrylic Oligomer Based on Butadiene Dimer for Anti-Corrosion Surfacing

Постановка задачи. В задачу работы входила оценка эффективности модифицирующего влияния соолигомера 4-винилциклогексена с метилметакрилатом (ОБММА-50) на свойства антикоррозионного покрытия на основе сополимера КОРС, полученного с использованием кубовых остатков ректификации стирола для повышения технологических и эксплуатационных физико-механических характеристик исходного покрытия. Результаты. Установлены функциональные, структурные и конформационные особенности исходного сополимера и олигомерного модификатора, которые обеспечивают их совместимость при формировании антикоррозионного покрытия. Выявлен оптимальный рецептурный состав и эффективный интервал содержания акрилового олигомера, где наблюдается повышение технологических и физико-механических показателей исходного антикоррозионного покрытия от 15 до 100 %. Выводы. Показаны те особенности в структуре и составе исходного полимера и акрилового модификатора, которые обеспечивают существенное повышение физико-механических показателей покрытия, содержащего в своем составе оптимальную концентрацию акрилового олигомера. Statement of the problem. The objective of the work was to assess the effectiveness of the modifying effect of the 4-vinylcyclohexene co-oligomer with methyl methacrylate (OBMMA-50) on the properties of an anticorrosion coating based on KORS copolymer obtained using styrene rectification residues to increase the technological and operational physical and mechanical characteristics of the initial coating. Results. The functional, structural and conformational features of the initial copolymer and oligomeric modifier are established, which ensure their compatibility in the formation of an anti-corrosion surfacing. The optimal prescription composition and effective range of the acrylic oligomer content were revealed, where there is an increase in technological and physico-mechanical parameters of the initial anti-corrosion surfacing from 15 to 100 %. Conclusions. The features in the structure and composition of the starting polymer and acrylic modifier are shown that provide a significant increase in the physical and mechanical parameters of the coating containing the optimal concentration of acrylic oligomer in its composition.

Method of estimating the effective zone induced by rapid impact compaction

This paper proposes a method for estimating the effective zone, including effective depth and effective range of compaction degree, from rapid impact compaction (RIC) on sand layer whose fines content is less than 10%. The proposed method utilizes a string of microelectromechanical system accelerometers to monitor the acceleration at various depths and propagation distances during compaction. To interpret and extract useful information from monitored data, peak-over-threshold (POT) processing and normal distribution function were used to analyze the recorded acceleration. The mean and standard deviation of the threshold peak acceleration were used to evaluate the effective depth and the effective range of compaction degree during RIC compaction. Moreover, spatial contours were used to determine the correlation of the threshold peak acceleration against depth and propagation distance from the RIC impact point. These contours help indicating the distribution of the effect zone after compaction. Lastly, a proposed method is suggested for frequent use in trial tests to quickly determine RIC’s required depth and impact spacing.

Development of Motion Graphic as Education Material for Promoting Shipping Industry Using EPIC Model Testing

Education related to problems in the shipping industry to the general public who have no background in the shipping industry and activities when ships dock at the port becomes a challenge to conduct research. This research develops multimedia motion graphics to combine graphic design, animation, text, and sound in visualizing materials and activities in the shipping industry. Stages of making multimedia start from ideas, narration, storyboard, tracing, editing, rendering, and testing. The research uses the EPIC Model testing by paying attention to aspects of empathy, persuasion, impact, and communication. The results of testing the effectiveness of the EPIC model obtained an EPIC rate of 4.15, which means that the resulting motion graph falls within the effective range criteria. Index terms— multimedia; motion graphic; EPIC model; effectiveness

TO STUDY THE POSSIBILITIES OF USING THE SEISMOLOGICAL NETWORK OF THE ALTAI-SAYAN REGION FOR REGIME VIBRO-SEISMIC OBSERVATIONS

The results of experiments on the study of the radiation characteristics of powerful vibrators and reception conditions at a number of seismic stations in the Altai-Sayan region in the range of distances of 50-450 kilometers in the problem of selecting points for active vibro-seismic monitoring are presented. It is shown that the real effective range of the CV-40 vibrator can be significantly increased by using multiple and semi-multiple harmonics. A method for assessing the applicability of stations for vibration monitoring using special programs for assessing the seismic background and seismic resonances within the boundaries of the location of seismic stations is proposed and tested.

New perspective on the powers and limitations of potentiometric redox measurements, a possible game changer

<p>The redox potential (Eh) is a master variable affecting speciation and fate of nutrients and pollutants in aqueous environments. To date, direct potentiometric measurements using redox electrodes are the only viable means of monitoring Eh in-situ and continuously. While some scholars indicated the quantitative value of this direct Eh measurement, many have argued that because there are often discrepancies between the measured Eh and the measured speciation of redox active species in solution, the electrode measurements can be regarded as qualitative at best. The ambiguity regarding the quantitative power of potentiometric Eh measurements has led many to disregard this important analytical tool. The question is raised – are there environments in which redox electrodes give a more reliable representation of the redox state than others? We investigated this question in a simplified system of solubilized Fe in different concentrations and various ratios of FeCl<sub>3</sub> to FeSO<sub>4</sub>. HCl and KCl were added to achieve different pH value (in the range of 2-4) and ionic strength levels (10-100 mM). The solutions were maintained stirred and were monitored continuously and simulatenously using 7 permanently installed redox electrodes with a data logger. The electrode readings were compared with the Eh calculated by external measurement of Fe speciation and the known solution inputs. In the initial solution, where only the ferrous iron form was added, a standard deviation of ~10mV was found between the electrodes used in this study; additions of Ferric iron to these solutions led to a decrease in standard deviation between electrodes down to ~2mV and concurrently to a convergence between electrode readings and the Nernst-based calculated Eh. The increased deviation in low ferric iron concentrations occurred regardless of the measuring device or if an external reference electrode was used. These findings suggest that potentiometric measurements have an effective range for which they can be used, which has been widely overlooked in the literature.  We examined different indices to define the effective range. Using the standard deviation as the index of the effective range, it was determined that in the tested solutions deviations increased when Fe<sup>+3 </sup>molar activity was <20 nM at an ionic strength of 10-20mM; but the rise occurred at a lower value (<5nM) in solutions with ionic strength ~100mM. The increased effective range at higher ionic strength points towards electron shuttling as a possible effector of the electrode range; if so, it is postulated that in natural systems, electron shuttling by organic matter may greatly increase electrode effective range. We believe that once the understanding that potentiometric redox measurements have an effective range is further established and explored it may be a game changer which will promote both the development of methods to define the effective range and technical improvements to increase electrode effective range so that potentiometric redox measurements can be more widely utilized as a quantitative tool.</p>