Analyses of sedimentology, ichnology and depositional environments of Langhian–Tortonian siliciclastic deposits in the southern Tebessa Basin (eastern Algeria) have revealed a tidally dominated deltaic setting with a high concentration of vertical burrows. From south to north, two depositional environments are here distinguished in the Tebessa Basin: a subaerial lower delta plain in the Oum Ali region with the trace fossils Ophiomorpha and Skolithos linearis, and a proximal delta front with numerous Skolithos, situated in the Hjer Essefra area. The occurrence of Skolithos pipe rock in this Miocene subtidal domain is unusual. Pipe rocks have been commonly reported from shallow and well-oxygenated environments, especially from Cambrian strata; their number decreased significantly during the Ordovician, coupled with an increase in biodiversity. Here different deltaic subenvironments and tidal signals that are exceptionally well preserved in outcrops are analysed and interpreted. Different ichnotaxa are briefly described, and the uncommon density and size of Skolithos pipe-rock in these Miocene strata are discussed.
Although deltas and subaqueous fans are both formed in the same near-shore zones of basins, the hydraulic conditions for their formation, development and sedimentary records are different. The present review discusses the results of previously published studies of fan deltas (Gilbert-type deltas) and subaqueous fans of lacustrine and glaciolacustrine environments. The depositional mechanisms of deltas and subaqueous fans, textural and structural features of the lithofacies associations and their typical lithofacies are presented. The characteristics of subaqueous fans, which are still relatively poorly understood and are often overlooked in sedimentological interpretations of lacustrine sedimentary successions, receive particular attention. The palaeoenvironmental and lithological differences between deltas and subaqueous fans are highlighted.
This study used repeat satellite imagery and Geographic Information System analysis to assess the planform dynamics along the length of the lower Niger River Valley from Onitsha city to the coast between 1985 and 2015. The aim is to understand the altered dynamics and its plausible causes in this data-poor region. Analyses revealed that the Niger River has undergone change corresponding to enhanced instability in terms of an increased rate of erosion. In the study area, a change was observed from 3.7% of deposition in the first 10 years (1985–1995) to 3.9% of erosion in the next 10 years (1995–2005) and 4.7% of erosion in the last 10 years (2005–2015). Total erosion over the 30-year period (1985–2015) in the delta was calculated on 4.8%. The river channel has migrated toward the east in the upper and lower reaches while the mid-section of the channel is migrating towards the west. The east river bank is observed to be more unstable compared to west bank line through the study period. The maximum shifts identified were 3.35 km of deposition in 10 years (1985–1995), 3.31 km of erosion in the next 10 years (1995–2005), and another substantial erosional shift of 3.35 km in the next 10 years (2005–2015). Avulsion rates gradually moved from −42.1 m ∙ year−1 (1985–2005, segment F) to 100.2 m ∙ year−1 (1985–1995, segment D), large deposition in the first 10 years. Total avulsion rates of the delta in the last 30 years (1985–2015) has pointed on erosion (−2.2 m ∙ year−1). The altered dynamics observed would likely threaten the future of the fragile lower river system environment and raise concerns for operators with infrastructure within the Niger Delta.
The Suchedniów water reservoir is located in the central section of the River Kamionka in the northern part of the Holy Cross Mountains of central Poland. This area once belonged to the Old Polish Industrial District that, during the Middle Ages, was very intensively developed by iron metallurgy. Many forges and mills along the rivers used water power, which led to the construction of an anthropogenic, small-scale water retention system. At the beginning of the twentieth century many of these reservoirs were drained after the collapse of metallurgical activities. The present-day reservoir was built in 1974 and drained in 2017. Research into the drained basin has documented various forms and sediments, some of which record present-day depositional processes (fire proof clay layer, inland fan delta), while others represent the historical period (lacustrine sediments of older reservoirs). Traces of catastrophic events have been preserved as well; an assemblage of megaripples marks the sudden drainage caused by a dam break in 1974.
Artykuł dotyczy projektu silnika z magnesami trwałymi małej mocy. W przypadku napędów małej mocy pracujących w sposób ciągły, sprawność ogólna układu napędowego odrywa istotną rolę. Na przykładzie klasycznego rozwiązania 12/8 przeprowadzono analizę wpływu konfiguracji uzwojeń (gwiazda, trójkąt) oraz sposobu sterowania pracą (BLDCM, PMSM) na właściwości maszyny. Wskazano rozwiązanie zapewniające maksymalną sprawność.
EN
This article refers to the low power permanent-magnet motor project. In the case of low power drives operating in a continuous mode, overall efficiency of the electric drive system plays an important role. On the example of the classic 12/8 solution, conducted an analysis of influence of winding configurations (star, delta) and drive technics (BLDC, PMSM) on the machine properties. Solution providing maximum efficiency was pointed out.
W artykule przedstawiono wyniki badań symulacyjnych i eksperymentalnych wielobiegunowego bezszczotkowego silnika prądu stałego z magnesami trwałymi. Rozpatrywano dwie konfiguracje uzwojeń silnika, tj. połączenie w gwiazdę i trójkąt przy założeniu stałych danych nawojowych. Na bazie obliczeń numerycznych wyznaczono momentowe charakterystyki statyczne silnika oraz ruchowe w pełnym zakresie zmiany prędkości obrotowej. W warunkach laboratoryjnych dokonano weryfikacji obliczeń numerycznych.
EN
In the paper, results of simulation and laboratory tests of a multi-pole brushless DC motor with permanent magnets were presented. Studies were carried out for two cases (i.e. wye winding configuration and delta winding configuration) on the assumption that winding parameters are constant. The static torque characteristic and the torque-speed characteristic over full speed range were determined based on numerical calculations. Simulation results were validated by a comparison with the laboratory test results.
Ancient deltaic facies are difficult to differentiate from tidally influenced shallow-marine facies. The Wagad Sandstone Formation of the Wagad Highland (eastern Kachchh Basin) is typified by offshore and deltaic facies with sedimentary characteristics that represent different conditions of hydrodynamics and related depositional processes. The study area, the Adhoi Anticline, constitutes a ~154-m-thick, shale-dominated sequence with progressive upward intercalations of bioturbated micritic sandstone and quartz arenite. Two thick Astarte beds (sandy allochemic limestone), with an erosional base and gravel blanketing, illustrate tidal amplification and high-energy stochastic events such as storms. Sedimentological characteristics document three depositional facies: an offshore, shale-dominated sequence prograding to proximal prodeltaic micritic sandstone and quartz arenite with sandy allochemic limestones, further prograding to mouth bars and abandoned channel deposits. The Wagad Sandstone Formation displays depositional environmental conditions that are dissimilar from those of coeval deposits in Kachchh sub-basins as well as on regional and global scales. This is attributed to a reactivation of the Kachchh Mainland and South Wagad faults which resulted in detachment and uplift of the Wagad block which then experienced prograding deltaic conditions.
Przedstawiono powody dla których budowa zbiorników wody słodkiej powoduje destrukcję delt i spowolnienie tworzenia fiordów. Podano przykłady problemów w utrzymaniu stanu posiadania lądu w warunkach załamania transportu osadu rzekami do morza.
EN
Some mechanisms of destructing deltas and speeding down creation of fiords by constructing large fresh water reservoirs have been described. The material has been illustrated by examples of problems with keeping the sea shore area the same as previously in the case of collapse of the sediment transportation by rivers to the sea.
This paper presents past and recent water management in the area called the Vistula Delta Fens (Żuławy Fens). This area (56 x 56 km) is located at the outlet of the Vistula River to the Baltic Sea, at the shore of the Gulf of Gdańsk. A large part of the area (30%) is located below sea level as potentially submerged depressions. A multitude of rivers, channels, ditches and pumping stations have been constructed here over several centuries. The area is characterized by highly productive alluvial soils, surface water with a high potential for fish-farming and fishery, and attractive tourist areas at the banks of the rivers and channels. Historically, floods have occurred repeatedly as a result of: (i) – breaks in the dams along big rivers, e.g. after heavy rains and high water levels (in summer); (ii) – dam breaks caused by accumulation of ice-cakes in winter or during spring times; (iii) – dam breaks after storms on the sea with increasing sea water levels at the river outlets (mainly in winter); (iv) – overflow of water into flat land after heavy rains followed by slow drainage of water from the fields, ditches, channels and pumping stations (in summer); (v) – overflow of water into depressions and swamps below sea level after interruptions of, or decreases in, the pump operations at the pumping stations. The EU directive on flood control advises that the member countries should: (i) – produce maps of the areas vulnerable to floods to facilitate communication and planning; (ii) – develop management plans for flooding events; (iii) – exchange experience and codes of good practice during flood; (iv) – facilitate a close cooperation between the scientific community and politicians in the field of flood protection; (v) – raise the level of knowledge, communication and awareness among local societies living in areas prone to flooding.
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The article presents the results of studies concerning the delta forms that arise as a result of the sedimentation of the debris fed to water bodies by watercourses. The study covered several dozen anthropogenic water bodies in the Upper Silesia region, which is well known for its high degree of urbanisation and industrialisation. Basic research work included morphometric measurements of deltas, analyses of the mechanical and chemical composition of delta sediments and analyses of the chemical composition of the common reed growing on the deltas. The research has demonstrated that the deltas exhibit certain characteristics typical of anthropogenic forms that result from the pollutants found in watercourses. In delta sediments, grains of sand usually dominate, but in many cases the share of the < 0.02 mm fraction is as high as ca. 30%. Sediments often contain fine coal and other organic pollutants, which is reflected by high weight loss on ignition. The content of trace elements in delta sediments is usually many times higher than the geochemical background for all types of sedimentary rocks. Deltas are an environment where pollutants accumulate and some of them are assimilated by plants. The content of macro elements in common reed tissues from different deltas does not vary widely while the content of trace elements often results from their content in the sediments. The material that forms deltas can be extracted and in some cases even used as fuel.
PL
Przedstawiono wyniki badań form deltowych, powstających w wyniku sedymentacji rumowiska wnoszonego przez cieki do zbiorników wodnych. Badaniami objęto kilkadziesiąt zbiorników antropogenicznych w regionie górnośląskim, wyróżniającym się silną urbanizacją i uprzemysłowieniem. Podstawowe prace badawcze obejmowały: pomiary morfometryczne delt, analizy składu mechanicznego oraz chemicznego osadów deltowych, analizy składu chemicznego trzciny porastającej delty. Prace badawcze wykazały, że delty mają cechy form antropogenicznych, wynikające z zanieczyszczenia cieków. W osadach delt dominują zwykle ziarna piasku, lecz w wielu przypadkach frakcja < 0,02 mm stanowi nawet około 30%. Osady nierzadko zawierają miał węglowy i inne zanieczyszczenia organiczne, co wyrażają wysokie wartości strat wagowych po prażeniu. Zawartość pierwiastków śladowych w osadach deltowych najczęściej wielokrotnie przekracza tło geochemiczne wszystkich rodzajów skał osadowych. Delty są środowiskiem akumulacji zanieczyszczeń. Część z nich jest asymilowana przez roślinność. Zawartość makropierwiastków w tkankach trzciny z różnych delt jest mało zróżnicowana, natomiast zawartość mikropierwiastków często jest pochodną zawartości w materiale osadowym. Materiał tworzący delty może być wydobywany - w niektórych przypadkach posiada nawet cechy opałowe.
The Adriatic Sea is an epicontinental, closed sea, part of the Mediterranean. It formed in the Late Miocene, and ended structurally during the Pliocene and Quaternary, when most of its sediments were deposited. The larger Pliocene and Quaternary depressions occur mostly by the western coast, where the deposits are several thousand metres thick, and were sourced from the Alps and the Apennines. The east coast is characterised by the large and elongated Dinarides Mts., that have continental drainage extremely close to the shoreline and a very small erosional rate. Consequently, eastern inflows were and are very short, including strongly tidal estuaries that erode only small volumes of mostly carbonate detritus, adjacent to frontal islands or mountains, with restricted depositional areas. The Neretva River deposits make up part of the largest contemporary delta system on the eastern Adriatic coast, and have been analysed in this study using three seismic sections and one exploration well. These deposits are recognized inside the Neretva and Korčula channels, assuming that processes operating during Quaternary glacial phases shifted the delta tens of kilometres to the west in the past on several occasions.
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Archaeological studies in the upper and lower part of the Ganga-Bhaghrathi-Hugli delta were taken up to understand the nature of site formation and human adaptation in a dynamic fluvial zone. This aspect has been neglected in Indian archaeology. However archaeological dating using ty-pological information, has an error margin of a couple of centuries and hence, is of limited use. We suggest that high resolution chronology using Optically Stimulated Luminescence (OSL) and radio-carbon dating can be quite effective in the study of archaeology and human environment relationship in the Ganga-Brahmaputra Delta (GBD).
Przy wykorzystaniu map dawnych, a także badań i obserwacji terenowych autorzy dokonali oceny stopnia przekształcenia rzeźby dna doliny Słupi w jej środkowym biegu, na odcinku, na którym w latach 20. XX w. wybudowano szereg urządzeń hydrotechnicznych, w tym dwie elektrownie wodne i towarzyszące im zbiorniki dolinne. Badania wykazały, że dno doliny Słupi w ciągu ponad 80 lat przekształciło się w zróżnicowanym stopniu, a tempo i zasięg współczesnych procesów formo- i osadotwórczych są niewielkie, z wyjątkiem górnych części zbiorników i odcinka koryta Słupi położonego poniżej elektrowni Krzynia.
EN
The subject of the study is the channel and valley floor of the Słupia river along its >10 km length reach south of Słupsk. In the early 20th century this reach of the valley was heavily altered through channelization and drainage, followed by extensive hydro-engineering works in the 1920s. The aim of this study is to recognize the magnitude of geomorphic change in the channel and the valley floor consequent to these human-induced perturbations. In 2001–2007 monitoring of selected processes and sites was carried out and involved mapping and repeated surveying of shorelines of reservoirs, bathymetric measurements, assessment of shoreline landforms, and repeated photography. Shoreline erosion, delta progradation and wave behaviour were among the monitored processes. Hydropower stations have been working continuously since their opening, whereas the reservoirs have never been flushed or dredged. The most important consequence is the dominant role of sedimentation in re-shaping of the Słupia valley floor, whose pattern is the following: – in the shallowest part of the reservoirs (10–30 cm) an older floodplain has been quickly and completely covered by deposits and vegetation succession proceeds, – in the middle sections, where reservoirs widen out, delta progradation takes place, – fine material is deposited in near-dam widening and in local coves, most intensively if water depth is less than 1 m, with the contributing role of aquatic plants. The course of fluvial processes below the Krzynia power station is different. The channel is modelled by scour and lateral erosion, which develop because of local scouring. In the effect of scour, the floodplain has been extensively drained over many kilometers, resulting in drying-up of oxbows cut off during the early 20th century straightening, desiccation of pool floors. At the same time, meanders migrate at the rate of 0.4–0.8 m per year.
This paper presents past and recent water management in the area called the Vistula Delta Fens (Zulawy Fens). This area (56 x 56 km) is located at the outlet of the Vistula River to the Baltic Sea, at the shore of the Gulf of Gdansk. A large part of the area (30%) is located below sea level as potentially submerged depressions. A multitude of rivers, channels, ditches and pumping stations have been constructed here during several centuries. The area is characterized by highly productive alluvial soils, surface water with a high potential for fish-farming and fishery, and attractive tourist areas at the banks of the rivers and channels. Historically, floods have occurred repeatedly as a result of: i - breaks in the dams along of big rivers, e.g. after heavy rains and high water levels (in summer); ii - dam breaks caused by accumulation of ice-cakes in winter or during spring times; iii - dam breaks after storms on the sea with increasing sea water levels at the river outlets (mainly in winter); iv - overflow of water into flat land after heavy rains followed by slow drainage of water from the fields, ditches, channels and pumping stations (in summer); v - overflow of water into depressions and swamps below sea level after interruptions of, or decreases in, the pump operations at the pumping stations. The EU directive on flood control advises that the member countries should: i - produce maps of the areas vulnerable to floods to facilitate communication and planning; ii - develop management plans for flooding events; iii - exchange experience and codes of good practice during flood; iv - facilitate a close cooperation between the scientific society and politicians in the field of flood protection; v - rise the level of knowledge, communication and awareness among local societies living in areas prone to flooding.
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The paper presents a comparative analysis of two different river mouths from two different geographical zones (subtropical and temperate climatic regions). One is the multi-branch and multi-spit mouth of the Red River on the Gulf of Tonkin (Vietnam), the other is the smaller delta of the river Vistula on a bay of the Baltic Sea (Poland). The analysis focuses on the similarities and differences in the hydrodynamics between these estuaries and the adjacent coastal zones, the features of sediment transport, and the long-term morphodynamics of the river outlets. Salinity and water level are also discussed, the latter also in the context of the anticipated global effect of accelerated sea level rise. The analysis shows that the climatic and environmental conditions associated with geographical zones give rise to fundamental differences in the generation and dynamic evolution of the river mouths.
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The water regime, location and origin are the features which make Lake Druzno an example of a unique water reservoir in every aspect. From the hydrographic point of view, it undergoes both natural (gravitational) and forced (polder) drainage. The authors believe that Lake Druzno did not use to be initially part of the Vistula Lagoon, and its origin is related to the formation of an end depression of a glacier lobe. Due to its situation, morphometric features and character of the bed, Lake Druzno is an environment of rich resources of organic life, which emphasises its unique character still more. The history of the development and present hydrological structure of Lake Druzno are crucial for an evaluation of the abiotic conditions influencing the state of the ecosystem.
PL
Jezioro Druzno ze względu na reżim wodny, położenie i genezę stanowi przykład zbiornika wodnego o wielu cechach znamionujących jego unikatowy charakter. Pod względem hydrograficznym jest ono włączone zarówno w naturalny (grawitacyjny) sposób odwadniania, jak i wymuszony - polderowy. Wielu autorów uważa, że jezioro Druzno nie stanowiło początkowo części Zalewu Wiślanego a jego powstanie wiążą z wytworzeniem się depresji końcowej lobu lodowcowego. Z uwagi na położenie, cechy morfometryczne, charakter podłoża - jezioro Druzno stanowi środowisko o bogatych zasobach życia organicznego, co dodatkowo podkreśla jego unikatowy charakter. Historia rozwoju i współczesna struktura hydrologiczna jeziora Druzno mają istotne znaczenie dla oceny abiotycznych uwarunkowań, wpływających na stan ekosystemu. Niniejsza praca ma zatem na celu określenie abiotycznych uwarunkowań ekosystemu, wpływających na reżim hydrologiczny zlewni jeziora Druzno przy uwzględnieniu specyficznych cech tego zbiornika. Pod pojęciem uwarunkowań abiotycznych należy rozumieć uwarunkowania pozabiologiczne, tj. naturalne czynniki środowiska nieorganicznego, które oddziałują na układy biologiczne o różnym poziomie organizacji. Natomiast ekosystem należy traktować jako podstawową jednostkę funkcjonowania w przyrodzie, w której zachodzi obieg materii i energii tzn. przyrodę nieożywioną i żywą wraz z florą i fauną, które są współzależne. Obiekt badań jakim jest jezioro Druzno stanowi szczególny przypadek śródlądowego zbiornika wodnego, którego funkcjonowanie jest konsekwencją istniejących powiązań czynników naturalnych i antropogenicznych. Unikatowy charakter jeziora, poza wskazaną wyżej współzależnością, przejawia się w wielu innych aspektach funkcjonowania, szeroko rozumianego środowiska geograficznego, włączając weń także aspekt kulturowy. Z uwagi na dodatni bilans materii i energii misy jeziornej, ze szczególnym uwzględnieniem materii organicznej, jezioro Druzno i jego najbliższe otoczenie charakteryzuje się wyjątkowym bogactwem fauny i flory zarówno pod względem gatunkowym jak i populacyjnym. Jezioro Druzno stanowi także ważne ogniwo w układzie transportowym, jakim jest Kanał Elbląski. Kanał ten poza funkcją transportową stanowi przykład osiągnięć technicznych podporządkowanych wykorzystaniu systemu wodnego do celów użytkowych. Przedstawione wyżej uwarunkowania podkreślające funkcje jeziora Druzno wskazują, że należy dołożyć wszelkich starań w celu utrzymania istniejącego stanu i zabezpieczenia dalszego funkcjonowania tego unikalnego ze wszech miar systemu hydrograficznego, który dodatkowo przekłada się na inne elementy środowiska.
The 2-level fingerprint identification method is presented. The method starts with the extraction of structural features (minutiae points) which is based on the computed ridge orientation flow, and is composed of: division of an input image into blocks, computing directional image, smoothing directions, foreground/backround segmentation, directional filtering, binarization, thinning, minutiae detection and postprocessing. Classification (the 1-st level) is based on the number and locations of singular points (corel/delta points), witch are found based on Poincare index.At the 2-nd level, the matching between two sets of the minutiae points is performed: an unknown pattern, and those in the database.
PL
W artykule przedstawiono 2-stopniową metodę identyfikacji linii papilarnych. Zaproponowano nową metodę ekstrakcji cech (tzw. minutiae points), czyli punktów rozgałęzień linii oraz punktów końcowych, opartą na orientacji w blokach, wygładzanie kierunków w blokach, segmentacja, kierunkowa filtracja, binaryzacja, ścienianie, detekcja punktów charakterystycznych, przetwarzanie końcowe. Klasyfikacja (1-szy stopień) wykorzystuje liczbę oraz położenie tzw. punktów core i delta, które wyznacza się na podstawie indeksu Poincare. Identyfikacja na 2-gim stopniu polega na porównaniu dwóch zbiorów punktów charakterystycznych: nieznanej próbki oraz próbki wzorcowej.
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Na podstawie danych wiertniczych i sejsmicznych omówiono pokredową ewolucję geologiczną przedgórza Karpat. Wykazano zgodność przebiegu dolin rzek Wyżyny Małopolskiej z systemem paleodolin w podłożu miocenu. Przedstawiono zjawisko środkowobadeńskiej podmorskiej erozji na szelfie małopolskim i pogłębienia paleodolin o kilkaset metrów. Podano przypuszczalną przyczynę tego procesu. W zachodniej części przedgórza Karpat rozpoznano dolnosarmacką deltę zbudowaną z materiału skalnego pochodzącego z masywu świętokrzyskiego i dostarczanego dorzeczem Pra-Nidy neogeńskiej. Dokonano rekonstrukcji zachodniej części dolnosarmackiego basenu sedymentacyjnego
EN
The Palaeogene and Neogene geological evolution of the Carpathian Foreland is presented on the basis of boreholes and seismic data. The conformity of recent rivers flowing down from the Małopolska Upland with palaeovalleys on the Miocene basement is visible. The Middle Badenian submarine erosion of deposits on the area of palaeovalleys on the Carpathian Foreland is coused by sea-bottom streams of high energy. The palaovalleys were incissed several hundred meters. The Lower Sarmatian delta has occured in the western part of the Carpathian Foreland. Rock material has originated in the Holy-Cross Palaeozoic Massif. The palaeovalley of the Neogene Nida River has been a way of transport of clastics. The reconstruction of the western part of the Lower Sarmatian sedimentary basin is demonstrated
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