The global structural response model for multi-deck ships in concept design phase

This paper is an attempt to contribute to the improvement of an analysis model within overall structural synthesis procedure for the multi-deck ships. The paper is organized in two parts: modeling principles and model validation. Principles of the proposed generic model formulation on the global and sub-structure levels are given in detail while the load model is briefly summarized. The basic building blocks (macro-elements and gross-elements) for the modeling of ordinary stiffened panels, combining numerical and analytical approaches, are presented and discussed w.r.t. requirements for a multi-deck structure. Different surrogates (sets of elements and ordinary macro-elements) used for equivalent modeling of large side openings are evaluated, since the reduced shear stiffness of superstructure sides has large influence on the hull girder stress distributions along the entire cross section height. The generic ship models developed using outlined principles and the basic building blocks are further validated through complex examples of a large cruise ship and a livestock carrier. On the global level, the accuracy of the generic model w.r.t. the longitudinal stress distribution over ships height is compared with a standard full ship FE model. The results confirmed that the suggested structural modeling principles, based on the generic FE model can be applied for the fast investigation of different structural topological/geometrical concepts as well as for the ordinary scantling/material optimization.     

Impact of an inter‐basin water transfer and reservoir operation on a karst open streamflow hydrological regime: an example from the Dinaric karst (Croatia)

This paper describes the hydrological changes caused by inter‐basin water transfer and the reservoir development on the hydrological regimes of two rivers. The Sabljaki Reservoir in the Zagorska Mre?nica River and the Bukovik Reservoir in the upper Dobra River began operation in 1959. Both are part of the hydroelectric power plant (HEPP) Gojak, whose installed capacity is 50 m³/s. Their water volumes at the spillway altitudes of 320·10 and 320·15 m a. s. l. are 3·3 × 10⁶ and 0·24 × 10⁶ m³ respectively. Both the Dobra and Mre?nica Rivers are losing, sinking and underground karst rivers. A 9376‐m‐long tunnel provides water from the Sabljaki Reservoir to the HEPP Gojak, which was constructed in the Lower Dobra River. The Sabljaki Reservoir is located in the Pla?ki karst polje, while the Bukovik Reservoir is located in the neighbouring Ogulin karst polje. The consequences of the inter‐basin water transfer are strong and have caused abrupt changes in the hydrological regimes of the downstream sections of both rivers. At the same time, the construction and development of both the reservoirs have also caused hydrological changes to the upstream section of the Upper Dobra River. Copyright © 2010 John Wiley & Sons, Ltd.     

An anthropo-ecological approach to landscape use optimization

A method of landscape evaluation based on the anthropo-ecological approach is worked out. The procedure consists of three stages, viz., general, special and optimization. Within the general stage, the structural arrangement of the landscape is evaluated by means of the concept of geo-ecological sites (GES), which are distributed into four zones (A, B, C, D) according to the degrees of their anthropic disturbance. The zoning performed makes it possible to select those geo-ecological sites where eco-critical relationships can be expected to appear; in order to eliminate such situations, transition zones are calculated for the geo-ecological sites concerned. The outcome of this approach is a proposal of a new structural arrangement of the geo-ecological sites, solving eco-critical situations and serving as a basis for the special and optimization stages of the anthropo-ecological method.     

Stick-slip unstable shear failure as a source of high frequency elastic radiation

Summary The results of laboratory measurements on square perspex models with a stress concentrator under uniaxial compression are presented. An attempt was made to interpret these results in order to determine the mutual relations between the mechanical parameters characterizing the treated models, including their focal zones, parameters of model loading, parameters of seismogenic displacement and parameters of radiated elastic pulses. Particular attention was given to the study of slip displacement, slip velocity, rupture velocity, nucleation points of rupture propagation, nucleation points of elastic radiation and to the frequency analysis of radiated pulses. Measurements of the displacement in the focal zone enabled us to determine the source function, to construct theoretical seismograms in a far field and to compare them with the real pulses from ultrasonic transducers located there. This allowed testing theoretical and experimental approaches to the study of how slip displacement, slip velocity and rupture velocity are related to the parameters of radiated pulses.     

Measurement of a freezing nucleus content in a water sample — Evaluation of the method

Summary A drop freezing technique applied in laboratory research to heterogeneous ice nucleation is described. The quality of the obtained experimental data is studied both theoretically and experimentally. Attention is focused on the range of measurable freezing nucleus concentration, the accuracy, the correctness and the reproducibility of the results. Some mechanisms which could influence the correctness of the method are discussed. No mechanism significantly influencing the measurements was found. It is concluded that the present experimental method is an effective method of measuring a freezing nucleus content in a water sample.

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ama na uu m¶rt;a n¶rt;u mauu ¶rt; ¶rt; a ¶rt;. ¶rt;m ama mam n nuu m¶rt;a. uau ua a ¶rt;uana uum mauu ¶rt; ¶rt;, a mm, naum u nmumm mam. umum m uu a naum m¶rt;a, m u u ma.

     

Tidal deformations of viscoelastic body

Summary The tidal deformations of a viscoelastic body are studied using the simple Kelvin-Voigt model. Expressions for the phase lag and amplitude change of the displacement vector are derived. The energy dissipation rate is calculated for the main disturbing bodies and for diurnal and semidiurnal tidal waves.

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am nuu ¶rt;auu n ma ua-ma. ¶rt; au ¶rt; ana¶rt;au a u uu anum¶rt; ma u. aumaa m ¶rt;uunauu uu ¶rt; u a a m u nm .

     

On the gravitation absorption hypothesis

Summary It is recommended that the data from measurements with supraconducting gravity meters be also analysed with regard to verifying the gravitation absorption hypothesis. Based on theoretical data from a3-year period, the spectrum of the assumed effect of shielding the gravitational influence of the Sun by the Earth's body on the value of the acceleration of gravity has been calculated for the tidal station Brussels (Figs 2a–e).

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¶rt;aam aauuam ¶rt;a uu n¶rt;uaumau ma mu u nuunm n¶rt;auaumauu. a mmuu ¶rt;a a mmu nu¶rt; u nm n¶rt;naa ma auauaumau ¶rt;mu a m a uu u u mmu ¶rt; nuu mauu (u. 2a–).

     

The photoelectron spectra of some Tl-Sb sulphosalts

The results of X-ray induced photoelectron spectroscopy (XPS) experiments on several phases of the ternary system Tl-Sb-S are reported. The binding energies of the inner S, Sb and Tl electrons increase with increasing quantities of Sb and decreasing amounts of Tl in these compounds. This is explained by the influences of the proportions of the bonded metals on the effective electron affinity of S. The higher proportions of the more electronegative element bonded to S cause the increase of its effective electron affinity. The results for Tl₂S (carlinite), Tl₃SbS₃, TlSbS₂ (weissbergite), TlAsS₂ (lorandite) and Sb₂S₃ (antimonite) can be interpreted in this way. The results for Tl₄S₃ suggest a predominantly covalent character of bonding for both Tl(III) and Tl(I), which are present in this sulfide. From comparison with Tl₃SbS₄ it could be supposed that Tl(III)-S bond has a more covalent character than Sb(V)-S bond. The results for Tl₃SbS₄ are in agreement with crystal structure data and the results of Moessbauer spectroscopy. For AsS (realgar) the binding energies of the inner electrons of As and S significantly increase, showing that the electrons in molecular orbitals are less strongly bonded to individual atoms, as compared to pure elements. The results for the amorphous TlSb₅S₈ (corresponding in composition to parapierrotite) suggest that in amorphous compound the Tl-S bonding is stronger and the coordination of Tl more regular than in a crystalline one.     

Nonlinear adaptive regression predictors based on singular decomposition

Summary The paper deals with a non-linear regression model, linear in parameters. The least-squares adaptation method has been used to determine the model parameters. The conditionality problem in solving equations, which follows from the dependent predictors, has been suppressed by singular decomposition. This model is especially suitable for treating meteorological problems because non-linear processes, e.g. changes of air masses, changes of circulation patterns, etc., can be treated. The model has been tested in connection with the forecast of daily maximum and minimum temperatures. The RMS error lies in the range of 1–2°C, if the principal PPM is supposed.

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Резюме Оnuсывеamся мamемamuческuŭ annaрam нелuнеŭноŭ ре?rt;рессuонноŭ мо?rt;елu, лuнеŭноŭ оmнос umельно naрaмеmров. Для оnре?rt;еленuя naрaмеmров мо?rt;елu uсnользуеmся меmо?rt; нauменьщuх квa?rt;рamов. Плохaя обусловленносmь сuсmемы нauменьщuх квa?rt;рamов, коmорaя вызвaнa взauмноŭ зaвuсuмосmью nре?rt;uкmоров, всmрaняеmся nрu nомощu сuн?rt;улярноŭ ?rt;екомnозuцuu. Эma мо?rt;ель nо?rt;хо?rt;um ?rt;ля nрuмененuя в меmеороло?rt;uu, maк кaк онa nозволяеm рaбоmamь с нелuнеŭносmямu, кaк нanрuмер uзмененuе воз?rt;ущных мaсс, uзмененuе хaрaкmерa цuркуляцuu u m. n. Мо?rt;ель nроверяеmся нa nро?rt;нозе ?rt;невных мuнuмaльных u мaксuмaльных mемnерamур. Сре?rt;няя квa?rt;рamuческaя ошuбкa нaхо?rt;umся в uнmе?rt;рaле оm 1 ?rt;о 2° (uсnользовaн nрuнцun РРМ).

     

The extreme value distribution of 5-min rainfall data at Belgrade

Summary For practical applications both the parent distribution of rainfall intensities and the distribution of their annual maxima are of interest. The relationship between these two distributions cannot be obtained from classical extreme value theory because of seasonal variation and serial correlation in the data. Mathematical results for the distribution of maxima in m-dependent sequences are presented to illustrate the effect of local dependence on the extreme value distribution. The average number of exceedances in a cluster is an important parameter in the relationship between the parent and the extreme value distribution. For 5-min rainfall data from Belgrade, quantiles of the annual maxima are overestimated by about 10 mm h^–1 if the effect of serial correlation is ignored. This bias can easily be removed by taking the local clustering of large rainfall intensities in a rainy spell into account.With 4 Figures