Exotic final states in the $$\varphi ^8$$ multi-kink collisions

We study final states in the scattering of kinks and antikinks of the $$\varphi ^8$$ φ 8 field-theoretic model. We use the initial conditions in the form of two, three or four static or moving kinks. In the numerical experiments we observe a number of different processes such as emergence of static and moving oscillons, change of the kink’s topological sector, scattering of an oscillon by a kink, production of kink–antikink pairs in oscillon–oscillon collisions. In antikink–kink collisions for asymmetric kinks, we found resonance phenomena – escape windows.

Regional Seismic Characterization of Shallow Subsoil of Northern Apulia (Southern Italy)

A first-order seismic characterization of Northern Apulia (Southern Italy) has been provided by considering geological information and outcomes of a low-cost geophysical survey. In particular, 403 single-station ambient vibration measurements (HVSR techniques) distributed within the main settlements of the area have been considered to extract representative patterns deduced by Principal Component Analysis. The joint interpretation of these pieces of information allows the identification of three main domains (Gargano Promontory, Bradanic Through and Southern Apennines Fold and Thrust Belt), each characterized by specific seismic resonance phenomena. In particular, the Bradanic Through is homogeneously characterized by low frequency (<1 Hz) resonance effects associated with relatively deep (>100 m) seismic impedance, which is contrasting corresponding to the buried Apulian carbonate platform and/or sandy horizons located within the Plio-Pleistocene deposits. In the remaining ones, relatively high frequency (>1 Hz) resonance phenomena are ubiquitous due to the presence of shallower impedance contrasts (<100 m), which do not always correspond to the top of the geological bedrock. These general indications may be useful for a preliminary regional characterization of seismic response in the study area, which can be helpful for an effective planning of more detailed studies targeted to engineering purposes.

Variational Solutions for Resonances by a Finite-Difference Grid Method

We demonstrate that the finite difference grid method (FDM) can be simply modified to satisfy the variational principle and enable calculations of both real and complex poles of the scattering matrix. These complex poles are known as resonances and provide the energies and inverse lifetimes of the system under study (e.g., molecules) in metastable states. This approach allows incorporating finite grid methods in the study of resonance phenomena in chemistry. Possible applications include the calculation of electronic autoionization resonances which occur when ionization takes place as the bond lengths of the molecule are varied. Alternatively, the method can be applied to calculate nuclear predissociation resonances which are associated with activated complexes with finite lifetimes.

Harmonic Resonance Identification and Mitigation in Power System Using Modal Analysis

Due to a rising share of power electronic devices in power networks and the consequent rise in harmonic distortion, impedance resonances are an important issue. Nowadays, the frequency scan method is used for resonance phenomena identification and analysis. The main disadvantage of the method is its inability to decouple different resonance phenomena. This means that the method is also unable to provide sufficient information about the effects that the parameters of network elements have on different resonance phenomena. Furthermore, it was also noted that despite the fact that the harmonic resonance mode analysis is well described in the literature, there is a lack of systematic approach to the analysis procedure. Thus the main objective of this paper is to address this disadvantage and to propose a systematic approach to harmonic resonance analysis and mitigation, utilizing modal analysis. In the first part of the paper, dominant network nodes in terms of resonance amplification of harmonics are determined. This is done by analysis of the eigenvalues of the network admittance matrix. Using the eigenvalue analysis results, key parameters of network elements involved in a specific resonance are determined next. This is performed by calculating the critical mode (i.e., the mode that experiences resonance) sensitivity coefficients with respect to network parameters. In the second part of the paper, the procedure for modal resonance frequency shift is presented. The shift is performed by changing the value of a selected parameter so that the modal resonance frequency matches the desired resonance frequency value. The parameter value is calculated with the Newton–Rhapson method. Presented analysis considers both parallel and series resonances. The effectiveness of the proposed method is demonstrated on an actual industrial-network model.

Study of factors determining the amplitude-frequency characteristics of acoustic noise in well logging

The article considers the factors that affect the spectral characteristics of acoustic noise recorded in active horizontal wells during logging. Based on the results of physical experiments performed on well models, the presence of resonance phenomena in the acoustic volume of the wellbore, the influence of the location of sensor and the tool body on the measurement result under identical conditions, the need to calibrate downhole tools for bringing their characteristics to a single scale are shown.

Stochastic resonance of volatility influenced by price periodic information in financial market

General researches show that all kinds of random risk information and periodic information in the financial system are mainly transmitted to the asset price through influencing the volatility, thus impacting the whole market. So can the periodic information and random factors in the price be transmitted to the volatility in reverse and cause volatility changes? Hence, in this paper, we investigate the stochastic resonance of volatility which is influenced by price periodic information in financial market, based on our proposed periodic Brownian Motion model and absolute return volatility. The parameter estimation of the periodic Brownian Motion model is obtained by minimizing the mean square deviation between the theoretical and empirical return distributions for the CSI300 data set. The good agreements of the probability density functions of the price returns, realized volatility (RV) at 5 minutes, RV at 15 minutes and absolute return volatility between theoretical and empirical calculation are found. After simulating the absolute return volatility and signal power amplification (SPA) of volatility via periodic Brownian Motion model, the results indicated that (i) single and double inverse resonance phenomena can be observed in the function of SPA versus random information intensity or economic growth rate; (ii) multiple inverse resonance phenomena can be also observed for SPA versus frequency of periodic information. The results imply that the transmission of stochastic factors and periodic information is not only from the volatility to the price, but also from the price to the volatility.

Proposals for the design of overhead bridge span superstructures in view of the resonance phenomena on the Moscow – Petersburg High-Speed Railway

Objective: To develop proposals for designing the infrastructure of the Moscow – Petersburg High- Speed Railway (HSR) in view of the resonance patterns defined by the design solutions of the overhead bridge span superstructures. Methods: The HSR bridge project designs have been analyzed. Results: Proposals have been developed to account for the resonance patterns of high-speed trains movement along overhead bridge span superstructures designed by Mosgiprotrans JSC. Practical importance: The developed proposals make it possible to prevent the primary resonance during high-speed train movement along the HSR with superstructures designed by Mosgiprotrans JSC.