Analysis of clustering phenomena in ab initio approaches

An approach for explicit consideration of cluster effects in nuclear systems and accurate ab initio calculations of cluster characteristics of nuclei is devised. The essential block of the approach is a construction of a basis which incorporates both conventional No-Core Shell Model wave functions and translationally-invariant wave functions of various cluster channels. The results of computations of the total binding energies of 8Be nucleus as well as the spectroscopic factors of cluster channels (amount of clustering) are presented. An unexpected fresh result of the rigorous study is that the contribution of "non-clustered" components of the basis to the total binding energy is great even in the typical cluster systems such as the discussed nucleus

Distribution of Maximum Earthquake Magnitudes in Future Time Intervals, Application to the Seismicity of Japan (1923-2007)

We modify the new method for the statistical estimation of the tail distribution of earthquake seismic moments introduced by Pisarenko et al. [2009] and apply it to the earthquake catalog of Japan (1923-2007). The method is based on the two main limit theorems of the theory of extreme values and on the derived duality between the Generalized Pareto Distribution (GPD) and Generalized Extreme Value distribution (GEV). We obtain the distribution of maximum earthquake magnitudes in future time intervals of arbitrary duration tau. This distribution can be characterized by its quantile Qq(tau) at any desirable statistical level q. The quantile Qq(tau) provides a much more stable and robust characteristic than the traditional absolute maximum magnitude Mmax (Mmax can be obtained as the limit of Qq(tau) as q tends to 1, and tau tends to infinity). The best estimates of the parameters governing the distribution of Qq(tay) for Japan (1923-2007) are the following: Form parameter for GEV = -0.1901 +- 0.0717; position parameter GEV(tau=200)= 6.3387 +- 0.0380; spread parameter for GEV(tau=200)= 0.5995 +- 0.0223; Q_0.90,GEV(tau=10)= 8.34 +- 0.32. We also estimate Qq(tau) for a set of q-values and future time periods in the range for tau between 1 and 50 years from 2007. For comparison, the absolute maximum estimate Mmax from GEV, which is equal to 9.57 +- 0.86, has a scatter more than twice that of the 90 percent quantile Q_{0.90,GEV}(tau=10) of the maximum magnitude over the next 10 years counted from 2007.Comment: 15 pages + 10 figure

Multifractal Scaling of Thermally-Activated Rupture Processes

We propose a ``multifractal stress activation'' model combining thermally activated rupture and long memory stress relaxation, which predicts that seismic decay rates after mainshocks follow the Omori law $\sim 1/t^p$ with exponents $p$ linearly increasing with the magnitude $M_L$ of the mainshock and the inverse temperature. We carefully test this prediction on earthquake sequences in the Southern California Earthquake catalog: we find power law relaxations of seismic sequences triggered by mainshocks with exponents $p$ increasing with the mainshock magnitude by approximately $0.1-0.15$ for each magnitude unit increase, from $p(M_L=3) \approx 0.6$ to $p(M_L=7) \approx 1.1$, in good agreement with the prediction of the multifractal model.Comment: four pages and 2 figure

The chronostratigraphy of Late Pleistocene glacial and periglacial aeolian activity in the Tuktoyaktuk Coastlands, NWT, Canada

Aeolian periglacial sand deposits are common in the Tuktoyaktuk Coastlands of Western Arctic Canada. Regionally extensive and thick aeolian sand-sheet deposits have been observed in two major stratigraphic settings: within a sand unit characterized by large aeolian dune deposits; and interbedded with glaciofluvial outwash from the Laurentide Ice Sheet (LIS). Small, localized sand sheets have also been observed along the tops of sandy bluffs, within sequences of drained thermokarst lakes deposits and as an involuted veneer above buried basal ice of the LIS. On the basis of radiocarbon and optically stimulated luminescence (OSL) dates from preserved periglacial aeolian sand sheets and dunes a regional chronostratigraphy is presented which indicates that both extensive dunes and sand sheets accumulated mainly between ca 30 and 13 ka. A switch to dominantly sand-sheet aggradation at ca 14–13 ka, with sand sheets forming widely until ca 8 ka, is attributed to (a) surface armouring by glacial deposits associated with the advance of the LIS; and (b) amelioration of the climate from cold aridity. An absence of OSL dates between ca 8 and 1 ka suggests that sand sheets stabilized during much of the Holocene. Local sand-sheet aggradation during recent centuries has occurred near sandy bluffs and on the floors of drained thermokarst lakes. The OSL dates constrain the maximum extent of the LIS in the Tuktoyaktuk Coastlands to Marine Isotope Stage 2

New Approach to the Characterization of Mmax and of the Tail of the Distribution of Earthquake Magnitudes

We develop a new method for the statistical esitmation of the tail of the distribution of earthquake sizes recorded in the Worldwide Harvard catalog of seismic moments converted to mW-magnitudes (1977-2004 and 1977-2006). We show that using the set of maximum magnitudes (the set of T-maxima) in windows of duration T days provides a significant improvement over existing methods, in particular (i) by minimizing the negative impact of time-clustering of foreshock / main shock /aftershock sequences in the estimation of the tail of the magnitude distribution, and (ii) by providing via a simulation method reliable estimates of the biases in the Moment estimation procedure (which turns out to be more efficient than the Maximum Likelihood estimation). Using a simulation method, we have determined the optimal window size of the T-maxima to be T=500 days. We have estimated the following quantiles of the distribution of T-maxima of earthquake magnitudes for the whole period 1977-2006: Q_{0.16}(Mmax)=9.3, Q_{0.5}(Mmax)=9.7 and Q_{0.84}(Mmax)=10.3. Finally, we suggest two more stable statistical characterristics of the tail of the distribution of earthquake magnitudes: the quantile QT(q) of a high probability level q for the T-maxima, and the probability of exceedence for a high threshold magnitude. We obtained the following sample estimates for the global Harvard catalog: QT(q=0.98)=8.6 +- 0.2 and a probability for the T-maxima to exceed magnitude 8 equal to 0.13-0.20. The comparison between our estimates for the two periods 1977-2004 and 1977-2006, where the later period includes the great Sumatra earthquake, 24.12.2004, mW=9.0, confirms the instability of the estimation of the parameter Mmax and the stability of the two other estimates.Comment: 40 pages including 16 figures and 7 table

Use of power method for identification of nonlinearity parameters

Procedure of calculation of nonlinearity parameters by power method based on equations of balance of the source and consumer instantaneous powers components according to each separate harmonic is proposed. It is demonstrated that such an approach makes it possible to obtain the required number of equations for determination of the nonlinearity parameters. The method is verified using the example of calculation of parameters of a simple electric circuit with a nonlinear inductance.Предложена методика расчета параметров нелинейностей энергетическим методом, в основе которого лежат уравнения баланса составляющих мгновенной мощности источника и потребителя по каждой отдельной гармонике. Показано, что такой подход позволяет получить необходимое количество уравнений для определения параметров нелинейностей. Методика проверена на примере расчета параметров простейшей электрической цепи с нелинейной индуктивностью.Запропоновано методику розрахунку параметрів нелінійностей енергетичним методом, в основі якого лежать рівняння балансу складових миттєвої потужності джерела і споживача за кожною окремою гармонікою. Показано, що такий підхід дозволяє отримати необхідну кількість рівнянь для визначення параметрів нелінійностей. Методика перевірена на прикладі розрахунку параметрів найпростішого електричного кола з нелінійною індуктивністю

АЛЬТЕРНАТИВНІ ПОКАЗНИКИ ПОТУЖНОСТІ ЕЛЕКТРИЧНОЇ ЕНЕРГІЇ В ОДНОФАЗНОМУ КОЛІ З ПОЛІГАРМОНІЙНИМИ СТРУМОМ І НАПРУГОЮ

Introduction. Many electrical engineering issues use a power balance. It is compiled from averaged power values, and equivalent power is used to characterize power of transient processes. To account electricity, both mono- and polyharmonic currents and voltages use active and reactive power, the quality of electricity is not taken into account. Problem. A number of works are declared a certain number of power components that reflect indicators of quantity and quality of electrical energy. These components of power are subject to criticism. The order of determining power components requires algorithmization, as well the task of determining indicators that will reflect poor quality of energy. Goal. Development of a technique for determining the components of power in single-phase circuits with polyharmonic current and voltage, for definition electrical energy transmission indicators. Methodology. Based on analysis of power components determined in known papers and order of their calculation, the features of taking sign of sine and cosine orthogonal components are marked, depending on combination of numbers a current and voltage harmonics. Using Fourier theory of series and elements of the logic algebra, an algorithm for determining components of electric power energy is developed. Results. Highlighting active and reactive powers of the fundamental harmonic of current and voltage; active and reactive power; canonical power components; non-canonical power components, and proposed indicators of quality of transmission of electrical energy. Originality. Based on analysis of power represented by trigonometric Fourier series, the specific calculation of canonical and non-canonical components with use of a number of indicators of electric energy transmission is proposed that reflect its quality. Practical value. The proposed power components of transmission of electrical energy can be used in technical accounting systems.Мета. Розробка методики визначення компонент потужності, в однофазних колах з полігармонійними струмом та напругою, для формування показників передачі електричної енергії. Методика. Використовуючи теорію рядів Фур’є та елементи алгебри логіки, відмічені особливості винесення знаку ортогональних компонент потужності в залежності від комбінації номеру гармонік струму та напруги. Результати. Відокремлюючи активну та реактивну потужності основної гармоніки струму та напруги; активну та реактивну потужності; канонічні компоненти потужності; неканонічні компоненти потужності, запропоновано показники якості передачі електричної енергії. Наукова новизна. Потужність, представлена тригонометричним рядом Фур’є, містить канонічні та неканонічні компоненти, які відбивають якість електричної енергії. Практична значимість. Компоненти потужності, та показники передачі електричної енергії можуть бути використаними в системах технічного обліку для вимірювання обсягів якісної та неякісної енергії