4,341 research outputs found

    The Earth as a living planet: human-type diseases in the earthquake preparation process

    Get PDF
    The new field of complex systems supports the view that a number of systems arising from disciplines as diverse as physics, biology, engineering, and economics may have certain quantitative features that are intriguingly similar. The earth is a living planet where many complex systems run perfectly without stopping at all. The earthquake generation is a fundamental sign that the earth is a living planet. Recently, analyses have shown that human-brain-type disease appears during the earthquake generation process. Herein, we show that human-heart-type disease appears during the earthquake preparation of the earthquake process. The investigation is mainly attempted by means of critical phenomena, which have been proposed as the likely paradigm to explain the origins of both heart electric fluctuations and fracture induced electromagnetic fluctuations. We show that a time window of the damage evolution within the heterogeneous Earth's crust and the healthy heart's electrical action present the characteristic features of the critical point of a thermal second order phase transition. A dramatic breakdown of critical characteristics appears in the tail of the fracture process of heterogeneous system and the injury heart's electrical action. Analyses by means of Hurst exponent and wavelet decomposition further support the hypothesis that a dynamical analogy exists between the geological and biological systems under study

    Fraktalna analiza seizmoakustičnih signala u sedimentnim stijenama blizu površine na Kamčatki

    Get PDF
    We studied, by the mono- and multifractal detrended fluctuation analysis (DFA), time fluctuations in the dynamics of seismoacoustic data, recorded in Karymshina site, which is located in a seismic area of Kamchatka. We took a series of seismoacoustic responses to the regional seismic events with the mag-nitudes M > 4 for the period 2017–2018. The series was divided into three groups (high, medium and low) based on the amplitude of recorded seismoacoustic re-sponse. Background noise segments of the signals demonstrated monofractal behavior similar to white noise by almost constant values of generalized Hurst exponent Hq≈0.5 and very small width of the multifractal spectrum Δa ≈ 0.1. Analysis of the high amplitude seismoacoustic signals with clear P-, S- and coda waves showed that P- and S-waves demonstrate wider multifractal spectrum (ΔaP = 0.37, ΔaS = 0.35) and range of generalized Hurst exponents Hq in com-parison with coda wave, characterized by almost constant Hq and minimal width of multifractal spectrum (ΔaCODA = 0.13). We showed that the properties of the multifractal spectrum could be used in detection of seismic wave arrival, estima-tion its duration and separation of P-, S- and coda waves. Application of the monofractal DFA in a sliding window showed that the acoustic signal transits from monofractal and uncorrelated background noise (Hurst exponent equals to 0.5) into the long-range dependent state during seismic waves arrival, that is helpful in analysis of the signals, particularly in case of low amplitude acous-tic responses, usually demonstrating an unclear waveform. Difference in mul-tifractal spectrum width between the original low amplitude signal and its sur-rogates, obtained by random shuffling showed that the multifractality in the signal is dominantly due to long-range correlations.U ovom smo radu mono- i multifraktalnom detrendiranom fluktuacijskom analizom (DFA) proučavali vremenske fluktuacije u dinamici seizmoakustičnih podataka zabilježe-nih na postaji Karymshina, koja je smještena u seizmički aktivnom području Kamčatke. U analizi smo koristili niz seizmoakustičnih odziva prilagođenih na regionalne potrese s magnitudama M > 4 za razdoblje 2017.–2018. Niz smo podijelili u tri grupe (visoka, sred-nja i niska) na temelju amplitude zabilježenog seizmoakustičnog odziva. Dio mikroseiz-mičkog nemira prisutnog unutar signala iskazuje monofraktalnu strukturu sličnu bijelom šumu s gotovo konstantnim vrijednostima generaliziranog Hurstovog eksponenta Hq ≈ 0,5 i vrlo malom širinom multifraktalnog spektra Δa ≈ 0,1. Analiza seizmoakustičnog signa-la visoke amplitude s jasnim P-, S- i koda valovima pokazala je da P- i S-valovi pokazuju širi multifraktalni spektar (ΔaP = 0,37, ΔaS = 0,35) i raspon generaliziranih Hurstovih eksponenata Hq u usporedbi s koda valovima, koje karakterizira gotovo konstantan Hq i minimalna širina multifraktalnog spektra (ΔaCODA = 0,13). Pokazali smo da se svojstva multifraktalnog spektra mogu upotrijebiti za otkrivanje nailaska seizmičkih valova, pro-cjenu nihovog trajanja i razdvajanje P-, S- i koda valova. Primjena monofraktalne DFA metode na zapise u kliznom prozoru pokazala je da akustički signal prelazi iz monofrak-talnog i nekoreliranog mikroseizmičkog nemira (Hurstov eksponent jednak 0,5) u stanje dugog dometa tijekom dolaska seizmičkih valova, što je korisno u analizi signala, poseb-no u slučaju akustičnih odziva niske amplitude s nejasnim valnim oblikom. Razlika u širini multifraktalnog spektra između izvornog signala niske amplitude i njegovih zam-jenskih oblika, dobivenih nasumičnim odabirom, ukazuje da multifraktalnost u signalu dominantno ovisi o dalekosežnim korelacijama

    A review on IGBT module failure modes and lifetime testing

    Get PDF

    A sequential Bayesian approach to online power quality anomaly segmentation

    Get PDF
    Increased observability on power distribution networks can reveal signs of incipient faults which can develop into costly and unexpected plant failures. While low-cost sensing and communications infrastructure is facilitating this, it is also highlighting the complex nature of fault signals, a challenge which entails precisely extracting anomalous regions from continuous data streams before classifying the underlying fault signature. Doing this incorrectly will result in capture of uninformative data. Extraction processes can be confounded by operational noise on the network including harmonics produced by embedded generation. In this paper, an online model is proposed. Our Bayesian Changepoint Power Quality anomaly Segmentation allows automated segmentation of anomalies from continuous current waveforms, irrespective of noise. Demonstration of the effectiveness of the proposed technique is carried out with operational field data as well as a challenging simulated network, highlighting the ability to accommodate noise from typical network penetration levels of power electronic devices

    Effect of stress-strain conditions on physical precursors and failure stages development in rock samples

    Get PDF
    Precursory stages of failure development in large rock samples were studied and simultaneous observations of the space-time variation of several physical fields were carried out under different stress-strain states. The failure process was studied in detail. A hierarchical structure of discreet rock medium was obtained after loading. It was found that the moisture reduced the rock strength, increased the microcrack distribution and influenced the shape of the failure physical precursors. The rise in temperature up to 400 °C affected the physical precursors at the intermediate and final stages of the failure. Significant variations were detected in the acoustic and electromagnetic emissions. The coalescence criterion was slightly depending on the rock moisture and temperature effect. The possibility of identifying the precursory stage of failure at different strain conditions by means of a complex parameter derived from the convolution of physical recorded data is shown. The obtained results point out the efficiency of the laboratory modelling of seismic processe

    Field Detection of Microcracks to Define the Nucleation Stage of Earthquake Occurrence

    Get PDF
    Main shocks of natural earthquakes are known to be accompanied by preshocks which evolve following the modified Ohmori’s law in average over many samples. Individual preshock activity, however, is far less systematic for predictive purposes. On the other hand, the microcracks in laboratory rock experiments are always preceded to final rupture. And, previous investigations of field acoustic emissions showed that the activity increases prominently before and after the main shock. But there is no detection of any phenomena to identify the nucleation stage. Here we show that a special underground electric field measurement could detect microcracks. Pulse-like variations were classified into three groups (A, B, C) by frequency. The B-type is suggested to define the nucleation period: activity increases sharply following the modified Omori’s law before the main shock and there is no activity afterward. The B-type is subgrouped into three types possibly corresponding to crack-rupture modes. The variations are supposed to be induced by crack occurrence through electrokinetic effects in the elastic-porous medium. The detection distance is suggested to be several orders larger than that of the acoustic emission due to the effective smallness of dissipation rate, and the waveform can be used to infer the rupture mode
    corecore