Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 20

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last
Wyniki wyszukiwania
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
1
Content available remote Estimation of the durations of breaks in deposition – Speleothem case study
EN
Speleothems provide one of the most continuous terrestrial archives. However, due to changing conditions in temperature/humidity or the chemistry of percolating water, sedimentation breaks (hiatuses) and erosional events are possible and are commonly recorded in speleothems. Sedimentation breaks with durations longer than the resolution of the studied record should be considered in potential speleothem age-depth models. The most classic and reliable solution to the problem is the independent construction of age-depth models for the parts of speleothems separated by the hiatuses. However, in some cases, it is not possible to obtain a sufficient number of dating results for reliable age-depth model estimation. In such cases, the problem can be solved by the application of other sources of chronological information. Here, based on a few speleothem examples, an alternative approach – oxygen isotopic stratigraphy – is used to estimate the chronology for the parts of speleothems where there is not enough chronological information for classic age-depth models. As a result, the deposition break duration can be estimated.
EN
Mobile robots are becoming increasingly popular, finding a great deal of applications, especially in situations where conventional mobility systems, such as wheels or tracks, prove ineffective. Exploration of an unknown environment or a place, in which Man is incapable of staying, for example exploring remote planets in the Solar System, is often linked with operating a device in a rough terrain. This requires an adjustment of the robot locomotion system to the ground. The problem of high mobility in diverse surroundings is still a major challenge. Therefore, the concept of mobile robots is extremely popular and is still being developed. Using this type of propulsion carries several advantages, namely the possibility of applicability of this type of solutions in an environment, which is not easily accessible to wheeled vehicles (sandy, mountainous terrain, etc.). There is still a large interest of constructors and scientists in unconventional drive systems, adapted directly from nature, which often offers very efficient solutions. Quite frequently, designers copy the construction of animal locomotion system, attempting at implementing them in their designs. The aim of this article is to present an original construction, known as the Rhex-type robot in the available literature. In addition, it presents a number of conducted investigations, which describe the platform’s mobility in various terrains, such as sands, rocks and rubbles, as well as the possibility to overcome the terrain obstacles. It ends with conclusions and potential application areas of this type of a design.
EN
The quality of paleoenvironmental reconstruction based on speleothem records depends on the accuracy of the used proxies and the chronology of the studied record. As far as the dating method is concerned, in most cases, the best solution is the use of the U-series method to obtain a precise chronology. However, for older periods (i.e., over 0.5 Ma), dating has become a serious challenge. Theoretically, older materials could be dated with the U-Pb dating method. However, that method requires a relatively high uranium content (minimum of several ppm), whereas typical speleothems from Poland (and all of Central Europe) have uranium concentrations below 0.1 ppm. Because the materials in Polish caves are problematic, we applied oxygen isotope stratigraphy (OIS) as a tool for speleothem dating. By using OIS as an alternative tool to create a chronology of our flowstone, it was found that the studied flowstone crystallized from 975 to 470 ka with three major discontinuities, so obtained isotopic record can be correlated with oxygen isotopic stages from MIS 24 to MIS 12. The observed isotopic variability was also consistent and confirmed with the petrographic observations of the flowstone.
EN
The Niedźwiedzia Cave system is composed of 3 horizontal levels of passages and chambers. Changes in the drip rate of water from the upper level stalactites correlate well with changes in precipitation intensity. The transition time between the surface and the upper level of the cave was estimated to 14 days. Drip sites in the middle and lower levels of the cave exhibited two types of recharge: some did not correlate with precipitation intensity, whereas others correlated well with rain events. The transition times for the latter sites were estimated to be greater than 6 months. This estimate was confirmed by the calculation of the transition time based on tritium activity. The oldest water in the entire karst system was observed in a karst spring. The mean tritium age for this water during winter was estimated to be 3.9 ± 0.6 yr. More precise calculations of the tritium age of karst water require longer precipitation activity datasets.
PL
Kluczem do piękna i czystości zbiornika wodnego jest jego właściwe zaprojektowanie oraz pielęgnacja. Do tego celu warto wybrać techniki opierające się na zasadach ekologii.
PL
By projektować, budować, pielęgnować lub renaturyzować zbiorniki wodne, należy zdać sobie sprawę z ekologicznych uwarunkowań funkcjonowania tego typu obiektów. Niestety, rażące błędy konstrukcyjne, występujące nagminnie w obiektach tego typu, są regułą.
PL
Stawy kąpielowe to sztuczne systemy akwatyczne, w których wykorzystywane są naturalne procesy samooczyszczania się wód. Dlatego kąpieliska, gdzie nie stosuje się obróbki chemicznej wody są, atrakcyjną alternatywą dla konwencjonalnych basenów. Kąpiele odbywały się kiedyś wyłącznie w wodach naturalnych. Wraz z narastającym ich zanieczyszczeniem oraz rozwijającą się świadomością znaczenia higieny tworzono sztuczne baseny, w których woda była uzdatniana przy pomocy chemikaliów.
PL
Ostatnio coraz częsciej stosuje się filtry bagienne w środowisku miejskim, gdzie stają się integralną częścią zieleni, która wraz z założeniami wodnymi wywiera korzystny wpływ na mikroklimat obecny w przestrzeni publicznej.
EN
Lodowa Cave in Ciemniak, which belongs to the dynamic ice cave type, contains the biggest perennial block of cave-ice in the Tatra Mountains. The ice represents congelation type, since it originates from freezing of water which infiltrates the cave. Two generations of ice have been recognized in this cave. They are divided by the distinct unconformity. The ice building both generations is layered. Two moths which were found in the younger generations were sampled and dated by 14C method yielding 195 ± 30 and 125 ± 30 years. Bearing in mind the position in the section and the fact that the cave ice has waned since the 20s of the last century, the age is 1720-1820 AD and 1660-1790 AD respectively. It proves that the ice was formed during the Little Ice Age. Hence, the erosion boundary which underlies this generation records the degradation of ice before the Little Ice Age most probably during the Medieval Warm Period. The ice volume in the cave was substantially smaller before the Little Ice Age than it is today, despite the clear tendency to melting, which has been recognized since 20s of the last century. The older generation of ice is supposed to have its origins in a cold stage between the Atlantic period and the Medieval Warm Period.
10
Content available remote Deposition rate of lake sediments under different alternative stable states
EN
Sediments of five shallow lakes in Polesie Lubelskie region (Eastern Poland), representing a wide range of nutrient concentration, were dated by Pb-210 method and reliable age-depth models were constructed. These models were a base for studies of relationship between status of lake biocenoses and rate of sedimentation in the lakes. The sedimentation rate does not depend on ecological status of studied lakes. The highest mean sedimentation rate was found in phytoplankton-dominated (Lake Syczyńskie) and phytoplanktonmacrophyte- dominated (Lake Sumin) lakes. Macrophyte-dominated lakes represented intermediate values of deposition rate. Lake depth, area and hydrology are more important factors controlling sedimentation rate. The sedimentation rate was rather stable or changed over the time, depending on human management in the lakes’ drainage basins.
EN
Analysis of cladoceran remains was done on two cores from fossil lakes located near the Neolithic settlement site at Osłonki (Kujawy region, Poland). The cores provide records started from the Allerod and the Younger Dryas, respectively. The cladoceran remains were used to reconstruct natural and anthropogenic eutrophication and changes in water ecosystems. Both water bodies were shallow and clear-water lakes during the Late Glacial period. Since the beginning of the Holocene, climatic and biotic changes induced natural, slow and gradual eutrophication. The evidence of intensive eutrophication started with the first occurrences the pollen antl spores of crops and weeds. Human settlement caused significant changes in cladoceran species composition. The first occurrence of crop pollen was coincident with decline of plant-associated species and increase of euplanktonic taxa tolerant to high nutrient concentration.
EN
Sediments of two short cores collected from two basins of Kruklin Lake were studied by means of 210Pb and Cladocera analyses. The 210Pb allowed to date sediments and was helpful to obtain changes of sedimentation rate during the last two centuries. The CRS model was applied to calculate sediments age. Sedimentation rate differed strongly (from 0.55 cm/yr to 6.25 cm/yr) not only in time, but also between each basin. An accurate chronology of sediments was the basis for tracking of palaeolimnological changes with Cladocera analysis. Cladoceran planktonic:littoral ratio reflects event of artificial drop of lake water-level in the middle of nineteenth century. However, this event was recorded only in sediments of the southern, shallower basin and we suggest, that cladoceran planktonic:littoral ratio is better representative in shallow lakes. Changes of Cladocera assemblage composition suggest also strong eutrophication of lake water during the last century.
EN
Sediments of three oxbow lakes located in Vistula valley near Warsaw (Poland) were analysed for activity of 210Pb. The sediment age was calculated applying the CRS model. The sedimentation rate was determined for each lake based on the sediment age and thickness under the assumption of constant deposition between dated layers. Sedimentation rate varies in time and between lakes. The major changes of sedimentation rate were correlated with flood events and construction of flood dams that isolate the lakes from the river. The recent differences between the lakes seem to be related to different trophy state and productivity.
PL
W Unii Europejskiej od ponad dziesięciu lat funkcjonuje dobrowolny system rejestracji i ochrony produktów regionalnych. Produkty te swoją wyjątkowość zawdzięczają określonemu pochodzeniu geograficznemu i tradycyjnej metodzie wytwarzania. Podstawową i bezpośrednią przyczyną stworzenia w unijnym prawie odrębnych regulacji dla produktów regionalnych była chęć zapewnienia im ochrony, która uniemożliwiałaby fałszywe używanie nazw produktów oraz podrabianie tych unikalnych wyrobów.
EN
In this study we compared chydorid cladoceran (Chydoridae) taxa and assemblages from sediments of 6 Polish and 6 Finnish lakes and investigated if the difference in climate of these two countries can be detected in the cladoceran data. The data were analysed in terms of 1) average relative proportions of chydorid taxa during the history of each lake and by 2) redundancy analysis (RDA) to explain the present effect of environmental variables (altitude, area, maximum depth, mean annual temperature, mean summer temperature and length of the growing season) on species abundances. The redundancy analysis (RDA) enabled us to distinguih groups of taxa 1) with a high thermal preference 2) associated with small, cold-water lakes and 3) associated with shallow lakes. There are clear differences in the dominant chydorid taxa and in the relative proportions of many other chydorid taxa between the two countries since the end of the last glaciation. Although these differences first of all appear to reflect the climatic difference, the influence of many other environmental factors, controlling the living conditions of particular chydorids have been raised and considered. Further studies with larger data are needed before the role of climate can be reliably separated from other elements of environment.
16
Content available remote Wykorzystanie programu PRODAS do analizy balistyki pocisku
PL
W artykule przedstawiono proces symulacji numerycznej 122 mm pocisku OF-462 na podstawie wybranych modułów oprogramowania PRODAS. Uzyskane zbiory wyników obliczeń numerycznych na podstawie symulacji komputerowej dla rozpatrywanego pocisku artyleryjskiego zostały przedstawione zgodnie ze strukturą plików obliczeniowych.
EN
The numerical simulation process of the 122 mm OF-462 round made on the base of selected PRODAS program modules is presented. The sets of numerical calculation results received on the base of computer simulation for considered artillery round are presented in compliance with calculation file structure.
EN
Cladocera are a group of water animals, which are strongly dependent on environmental conditions. The ratio of planktonic to littoral Cladocera species is a widely used tool in palaeohydrological reconstruction of lakes' water level changes. Interpretation of this ratio is still unclear and requires further evidence. The simplest indicator of water level, which can be used in tracing lake-peat bog transitions, is the presence or absence of Cladocera and the character of its disappearance. In general, two models of Cladocera decline are observed. The first model is characterized by a very abrupt disappearance of all species, whereas the second one, with an intermediate stage, is characterized by domination of specific species. These two models are related to different types of terminal history of the water body. Even after a total disappearance of water in the peat bogs, there were episodes of some pioneer cladoceran species presence, correlated with periods of humid climate.
PL
Przedstawiony artykuł zawiera metodykę opracowania podstaw teoretycznych baz danych dla Systemów Kierowania Ogniem (SKO) pododdziałów artylerii naziemnej i zestawiania tabel strzelniczych w oparciu o teoretyczne procedury symulacji numerycznej ruchu pocisków na torze. Na podstawie opracowanej metodyki modelowania matematycznego i fizycznego ruchu przestrzennego pocisków w warunkach nominalnych i rzeczywistych został opracowany algorytm obliczeniowy oraz program do tworzenia baz danych oraz symulacji komputerowej z przeznaczeniem zgodnym z tematem artykułu.
EN
Introduced article contains methodic of elaboration of bases theoretical given bases for Systems Control with fire artillery over ground and of taking down of shooting - tables basing on theoretical procedures of simulation movement bullets on track. On base worked out methodic of fashioning mathematical and of physical movement of spatial bullets in circumstances nominał and real became worked out algorithm computational and programmer to creations of bases given and of coniDuter simulation with peaceable destination with theme this article.
EN
Lacustrine chalk is very common in post-glacial lakes of northern Poland. In the deposit of Lake Kruklin (NE Poland) carbonates occur as a layer 2-3 m thick. Samples for laboratory studies were collected from three profiles in SW part of the deposit. Mineral composition of the sediments was determined using differential thermal analysis (DTA) and thermogravimetry analysis (TGA), while the age was determined on the basis of pollen analysis. The sediment profiles represent an age of early Holocene. Calcite is the major component of lacustrine chalk. It forms small crystals (<10 ?m), sometimes grouped in aggregates, or present as bioclasts. Calcium carbonate precipitated from lake water. Chemical weathering of glacial and fluvioglacial material of the lake catchment is the main source of ions, transported to the lake mainly by groundwater. Formation of the Kruklin lacustrine chalk deposit must have required 300-350 kg of dry weight calcium carbonate to be carried away from each square meter of the lake catchment. If only top one-meter layer of glacial sediments had been decalcified, it should have contained 13-22 percent of calcium carbonate. The results of petrographic analysis show this value to be possible.
20
Content available Stawy kąpielowe - formy bliskie naturze
EN
Water in a swimming pond is purified through natural processes of self-cleaning so there is no need to use chemicals necessary to maintain traditional swimming pools. It is safe for humans and the environment, combining the benefits of a swimming pool and a garden pond. It may be used in private gardens and public recreational facilities. Its construction and maintenance is usually much cheaper and it blends harmoniously into the natural landscape. In this context, the authors discuss the basics of construction and maintenance of swimming ponds, selection of water plants, and relevant legal aspects.
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.