Reply to “Generation and propagation of transient nonlinear waves in a wave flume Wojciech Sulisz and Maciej Paprota 55:4 (2008) 277–287” [Coastal Engineering 56 (2009) 895–896]     

Wojciech Sulisz  Maciej Paprota 《Coastal Engineering》2010

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Small-scale trench in the north polar region of Mars: Evolution of surface frost and ground ice concentration     

Konrad J. Kossacki  Wojciech J. Markiewicz 《Icarus》2009,199(1):75-85

In this paper we attempt to answer the question, how formation of a small-scale trench in the martian regolith affects local distribution of the subsurface ice. We are especially interested in the consequences of digging a trench to search for buried ice, as has been done during the Phoenix Mars Lander mission. However, the results may be also applicable for natural troughs, or cracks. We present results of simulations of diurnal exchange of water between the regolith and the atmosphere. Our model includes the heat and vapor migration in the regolith surrounding the trench, as well as formation of diurnal frost. We take into account scattering of light in the atmosphere and on the trench facets, as well as changes of atmospheric humidity on diurnal and seasonal time scales. Our calculations show, that the measurements of ice content in a sample obtained within one, or two days from the beginning of digging should not be affected. However, on somewhat longer time scale at the south facing site of the trench the regolith can be significantly depleted from ice. This effect should be taken into account if the excavation and taking samples from different depths will be performed in stages separated in time by a month, or more.  相似文献   

Simple lattice model of macroevolution     

Wojciech Borkowski 《Planetary and Space Science》2009,57(4):498-507

In future astrobiology, like in modern astrophysics, the numerical simulations can be a very important tool for proving theories. In this paper, I propose a simple lattice model of a multi-species ecosystem suitable for the study of emergent properties of macroevolution. Unlike the majority of ecological models, the number of species is not fixed—they emerge by “mutation” of existing species, then survive or go extinct depending on the balance between local ecological interactions. The Monte-Carlo numerical simulations show that this model is able to qualitatively reproduce phenomena that have been empirically observed, like the dependence between size of the isolated area and the number of species inhabiting there, primary production and species-diversity. The model allows also studying the causes of mass extinctions and more generally, repeatability, and the role of pure chance in macroevolution.  相似文献   

A New Species Group in the Genus Tanytarsus van der Wulp(Diptera:Chironomidae)Based on a Fossil Record from Baltic Amber   总被引：1，自引：1，他引：0  

Wojciech GI?KA 《《地质学报》英文版》2010,84(4):714-719

<正>A new fossil chironomid,Tanytarsus serafini,found in Baltic amber is described and illustrated based on adult males.The new species and similar extant species of the genus Tanytarsus van der Wulp are compared. Due to several distinct characters of wing,legs and hypopygium,a new species group for Tanytarsus serafini is proposed,and its diagnostic features are evaluated.  相似文献   

Crustal structure of northern Spitsbergen along the deep seismic transect between the Molloy Deep and Nordaustlandet   总被引：1，自引：0，他引：1  

Wojciech Czuba  Oliver Ritzmann  Yuichi Nishimura  Marek Grad  Rolf Mjelde  Aleksander Guterch  Wilfried Jokat 《Geophysical Journal International》2005,161(2):347-364

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Unconfined linear flow to a horizontal well     

Wojciech Kawecki M  Al-Subaikhy HN 《Ground water》2005,43(4):606-610

The validity of a previously proposed but untested modification to equations for flow to a horizontal well is assessed using a specially developed finite-difference model. This modification extends confined flow equations to allow the head in the well and the saturated depth at the well to be estimated in unconfined conditions. The study is limited to the case of two-dimensional flow with no flow in the direction parallel to the line of the well. The results show that the modified equations for both a finite unconfined aquifer and, by inference, an infinite unconfined aquifer are adequately accurate for practical application.  相似文献   

Three-dimensional seismic modelling of crustal structure in the TESZ region based on POLONAISE''97 data     

Piotr roda  Wojciech Czuba  Marek Grad  Aleksander Guterch  Edward Gaczy ski  POLONAISE Working Group 《Tectonophysics》2002,360(1-4):169-185

This paper reports the results of 3-D tomographic modelling of crustal structure in the Trans European Suture Zone region (TESZ) of Poland, eastern Germany and Lithuania. The data are the product of a large-scale seismic experiment POLONAISE'97, which was carried out in 1997. This experiment was designed to provide some 3-D coverage. The TESZ forms the boundary between the Precambrian crustal terranes of the East European Craton (EEC) and the younger Phanerozoic terranes to the southwest. The 3-D results generally confirm the earth models derived by earlier 2-D analyses, but also add some important details as well as a 3-D perspective on the structure. The velocity model obtained shows substantial horizontal variations of crustal structure across the study area. Seismic modelling shows low (<6.1 km/s) velocities suggesting the presence of sedimentary rocks down to a depth of about 20 km in the Polish basin. The shape of the basin in the vicinity of the profile P4 shows significant asymmetry. Three-dimensional modelling also allowed tracing of horizontal irregularities of the basin shape as well as variations of the Moho depth not only along profiles, but also between them. The slice between P2 and P4 profiles shows about 10-km variations of the Moho over a 100-km interval. The crustal thickness varies from about 30 km in SW, beneath the Palaeozoic platform, to about 42 km beneath East European Craton in NE. High seismic velocities of about 6.6 km/s were found in the depth range 2–10 km, which coincides with K trzyn anorthosite massif. The results of this 3-D seismic modelling of the POLONAISE'97 data will ultimately be supplemented by inversion of seismic data from previous experiments.  相似文献   

The Annual Regime of Shallow Ground-Water Levels in Poland     

Wojciech Chelmicki 《Ground water》1993,31(3):383-388

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Wojciech Krzemi&#;ski 《Journal of Geodesy》1981,55(2):I

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Random vibrations of the baltic drilling platform subjected to wind loads and water waves     

Wojciech Jesie&#x; 《地震工程与结构动力学》1987,15(5):595-617

This paper presents random vibrations of the Baltic drilling platform subjected to water waves and wind loads. The platform structure is discretized by the finite element method. Linear beam or truss elements can be used. The structure parameters (i.e. mass, damping and stiffness) are assumed as deterministic. Soil is modelled as an elastic half-space that possesses deterministic or random parameters. Soil–structure interaction is idealized as a system of spring–dashpot elements connecting the structure and subsoil. The parameters of these elements can be random or deterministic. The sea surface is described by the one-dimensional wave spectrum that was proposed by Striekalov and Massel²⁴ for inland seas. It is suitable for the Baltic Sea. The wind velocity is described by the well-known Davenport spectrum. The water and wind loads are treated as stationary ergodic processes. Gaussian distributions and zero means of these processes are assumed. In addition to this, waves and wind loads are considered as independent. Such an assumption corresponds to the situation when the storm sea is fully developed. A frequency-domain random-vibration approach is utilized to obtain the dynamic response of the platform. The equations of motion of the problem were solved using modal reduction. The numerical calculations were made with a specially written computer program. From the results obtained, it is concluded that the wind influence on the response of the platform can be neglected. If random parameters are assumed for the subsoil, then the response of the system describes in a more realistic way the dynamic behaviour of the platform. The velocity coupling due to soil and hydrodynamical damping is negligible. This paper is a condensation of the author's Ph.D. thesis presented at the Technical University of Gdańsk in July 1985.  相似文献