Search results for: HYDRAULIC ROTARY MOTOR
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Pathways of nitrogen compounds depletion in hybrid constructed wetlands
PublicationHybrid Constructed Wetlands are composed of two or more filters with mixed flow direction of sewage. Apparently in the HCWS the benefits of both types of bed are merged, resulting in better effluent quality (organic and nitrogen componds removal). Such heterogeneous environment creates possibilities for different ways of nitrogen "disappearing". The objective of the present study was to compare the removal of nitrogen with accompanying...
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Channel Blockage and Flow Maldistribution during Unsteady Flow in a Model Microchannel Plate heat Exchanger
PublicationThis paper describes the problem of channel blockage as a result of flow maldistribution between the channels of a model mini channel plate heat exchanger consisting of one pass on each leg. Each leg of the heat exchanger contains 51 parallel and rectangular minichannels of four hydraulic diameters namely 461 μm, 571 μm, 750 μm and 823 μm. In addition, a more complex geometry has been investigated where for the sake of breaking...
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The Application of Granulated Expanded Glass Aggregate with Cement Grout as an Alternative Solution for Sub-Grade and Frost-Protection Sub-Base Layer in Road Construction
PublicationThe purpose of the research was to assess the possibility of using granulated expanded glass aggregate (GEGA) with cement grout as a replacement of a sub-grade and frost-protection layer, made of natural fine aggregates (NATU), stabilized with a hydraulic binder. Instead of traditional parts of the road construction, such as the sub-grade and frost-protection layer with the application of fine aggregate, stabilized with cement,...
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Pressure drop related to flow maldistribution in a model minichannel plate heat exchanger
PublicationThe paper describes the issues related to the pressure drop that accompanies the phenomenon of maldistribution of working fluid between the channels of a model minichannel plate heat exchanger. The research concerns a single exchanger's plate containing 51 (in every geometry) parallel rectangular minichannels of hydraulic diameters 461 µm, 571 µm, 750 µm and 823 µm. In addition, the more complex geometry has been investigated,...
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Analytical chemistry in technical approaches: immobilization of biosorbent waste containing heavy metals in cemented materials
PublicationAn ecologically safe and economically justified method of stabilization of the used biosorbents was developed. Sorbent contaminated with heavy metals has been successfully solidified/stabilized using a hydraulic binder. The test results indicated that up to 1% of the biosorbent residue used could be added without compromising the compressive strength of the mortar. The compressive strength of the modified mortars did not change...
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Automatic Watercraft Recognition and Identification on Water Areas Covered by Video Monitoring as Extension for Sea and River Traffic Supervision Systems
PublicationThe article presents the watercraft recognition and identification system as an extension for the presently used visual water area monitoring systems, such as VTS (Vessel Traffic Service) or RIS (River Information Service). The watercraft identification systems (AIS - Automatic Identification Systems) which are presently used in both sea and inland navigation require purchase and installation of relatively expensive transceivers...
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The Origins of the Concept of Ideology
PublicationThe concept of "ideology" as, firstly, a term that points at non-epistemological conditioning of cognitive processes, and, secondly, as a term which aimed at disclosing the ancillary role of given ideas in regard to specific political interests of certain groups, has long history. Since Francis Bacon's theory of idols modern philosophy endavoured to create a comprehensive classification of systematic cognitive errors which divert...
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Electric shock hazard in circuits with variable-speed drives
PublicationThe conventional approach to electrical safety under fault condition in typical power systems considers earth fault currents of sinusoidal waveform and frequency of 50/60 Hz. However, in circuits with variable-speed drives, there is earth fault current flow with harmonics, and these harmonics influence the threshold of ventricular fibrillation. The paper presents earth fault current waveforms in circuits with variable-speed drives...
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Wpływ błędów parametrów modelu maszyny indukcyjnej na działanie rozszerzonego obserwatora prędkości
PublicationW artykule opisano metodę odtwarzania prędkości wirnika maszyny indukcyjnej przy wykorzystaniu rozszerzonego obserwatora prędkości. Zbadano wpływ błędów parametrów modelu maszyny indukcyjnej na właściwości dynamiczne obserwatora poprzez porównanie macierzy stanu obserwatora obarczonego oraz nieobarczonego błędami parametrów. Zbadany został także wpływ błędów parametrów na jakość odtwarzania zmiennych maszyny w stanie ustalonym.
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Hydro and marine civil engineering (2023-2024)
e-Learning CoursesKurs realizowany na Wydziale Inżynierii Lądowej i Środowiska (WILiŚ) Politechniki Gdańskiej. Studia: II stopnia - magisterskie, stacjonarne Kierunek: Budownictwo Semestr: 1 (letni) Presentation of basic hydro and marine civil engineering structures together with basic computational procedures for determining environmental forces acting on a structure (vertical-wall breakwater, rubble mound breakwater, submarine pipelines...
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Hydro and marine civil engineering (2020-2021)
e-Learning CoursesKurs realizowany na Wydziale Inżynierii Lądowej i Środowiska (WILiŚ) Politechniki Gdańskiej. Studia: II stopnia - magisterskie, stacjonarne Kierunek: Budownictwo Semestr: 1 (letni) Presentation of basic hydro and marine civil engineering structures together with basic computational procedures for determining environmental forces acting on a structure (vertical-wall breakwater, rubble mound breakwater, submarine pipelines...
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Hydro and marine civil engineering (2021-2022)
e-Learning CoursesKurs realizowany na Wydziale Inżynierii Lądowej i Środowiska (WILiŚ) Politechniki Gdańskiej. Studia: II stopnia - magisterskie, stacjonarne Kierunek: Budownictwo Semestr: 1 (letni) Presentation of basic hydro and marine civil engineering structures together with basic computational procedures for determining environmental forces acting on a structure (vertical-wall breakwater, rubble mound breakwater, submarine pipelines...
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Wpływ imperfekcji geometrycznych na bezpieczeństwo montażu i naprawy zbiorników cylindrycznych metoda podbudowy
PublicationW pracy zajęto się wyznaczeniem nośności granicznej zbiorników stalowych o osi pionowej montowanych lub naprawianych z zastosowaniem hydraulicznego systemu podnoszenia konstrukcji. Podniesiony zbiornik jest szczególnie narażony na utratę stateczności, a obciążenie wiatrem utrudnia prowadzenie prac. Jakiekolwiek deformacje blach, szczególnie w pobliżu zamocowań podnośników mogą w znacznym stopniu obniżyć obciążenie krytyczne konstrukcji....
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Wielkogabarytowe hydrodynamiczne łożyska wzdłużne
PublicationW monografii przedstawiono problemy konstrukcyjne i badawcze hydrodynamicznych łożysk wzdłużnych o dużych średnicach. Łożyska takie stanowią istotne i niezwykle odpowiedzialne podzespoły hydrogeneratorów elektrowni wodnych. Z uwagi na rozmiary (średnice przekraczają niekiedy 5 metrów) i złożoność zjawisk łożyska te wymagają specjalnej postaci konstrukcyjnej, a ich dokładna analiza obliczeniowa przysparza wiele problemów. Dodatkowo...
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Katarzyna Staszewska dr inż.
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Liquefaction of alder wood as the source of renewable and sustainable polyols for preparation of polyurethane resins
PublicationLiquefaction of wood-based biomass gives different polyol properties depending on the reagents used. In this article, alder wood sawdust was liquefied with glycerol and poly(ethylene glycol) solvents. Liquefaction reactions were carried out at temperatures of 120, 150 and 170 °C. The obtained bio-polyols were analyzed in order to establish the process efficiency, hydroxyl number, acid value, viscosity and structural characteristics...
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Pathways of Nitrogen Removal in Hybrid Treatment Wetlands
PublicationHybrid Treatment Wetlands (HTWs) are composed of two or more filters with different modes of flow, allowing the benefits of both types of bed to be combined, resulting in better effluent quality (nitrogen and organic compounds removal). Such a heterogeneous environment creates possibilities for different mechanisms of nitrogen removal. The objective of the present study was to investigate the removal of nitrogen versus a range...
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Studies on the influence of technological variants of finishing machining on flow of parts in flexible manufacturing
PublicationIn the article below the problems of influence of variants of finishing processing on flow of machining parts in flexible manufacturing system were presented. The investigations were carried out the technological processes for piston rods and rams of hydraulic cylinders. There were also presented model variants of technological processes for piston rods finished with the burnishing. In these studies the influence of technological...
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Heat transfer intensification by enlarged surface roughness in the plate heat exchanger
PublicationIn the paper an experimental analysis of passive heat transfer intensification technique employed in the case of the plate heat exchanger is presented. The passive intensification was obtained by a modification of the heat transfer surface. The roughness of surface was increased by a use of glass micro-beads. Single-phase convective heat transfer in the water-water system was studied. The experiment was accomplished in two stages....
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Recent advances on the removal of phosphorus in aquatic plant-based systems
PublicationPhosphorus (P) is a vital nutrient for the ecosystems and its excess in wastewater streams leads to some environmental issues such as extensive algae growth (eutrophication). Phytoremediation is a green technology that is based on the combined actions of plants and their associated microbial groups to remove and transfer the toxic compounds in surface water, groundwater and soil. Aquatic plants are widely used for the remediation...
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Freeze-Up Ice Jam Formation in the River Bend, a Case Study on the Inner Mongolia Reach of Yellow River
PublicationConcern has been expressed regarding the impacts of climate change on river ice and ice jam formation in cold regions. Ice jams are easily initiated in bends and narrow channels and cause disasters. In this study, observations and remote sensing monitoring are used to study the freeze-up ice jam formation of bends. Sediment transport and freezing process of the river interact, influencing bed changes profile and sedimentary budget....
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Mobile satellite measurements in designing and exploitation of rail roads
PublicationThe article presents a summary of several years (2009-2015) of studies on the application of mobile satellite Global Navigation Satellite Systems (GNSS) measurements in the field of designing and operation of railways. These studies have been conducted by an interdisciplinary research team from the Gdansk University of Technology and the Gdynia Maritime University. Mobile satellite GNSS measurements are taken during a ride (through...
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Testing sensitivity of A-type residual current devices to earth fault currents with harmonics
PublicationIn many applications, modern current-using equipment utilizes power electronic converters to control the consumed power and to adjust the motor speed. Such equipment is used both in industrial and domestic installations. A characteristic feature of the converters is producing distorted earth fault currents, which contain a wide spectrum of harmonics, including high-order harmonics. Nowadays, protection against electric shock in...
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Experimental Research of an Axial Piston Pump with Displaced Swash Plate Axis of Rotation
PublicationThe article describes the influence of displacement of the swash plate rotation axis on the efficiency of axial piston pumps. The dead space volume was defined as the volume of the working chamber in the extreme position of the piston at the end of the pumping phase and its variability was determined as a function of the position of the axis of rotation of the swash plate and the swing angle of swash plate. The influence of swash...
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Selection of an artificial pre-training neural network for the classification of inland vessels based on their images
PublicationArtificial neural networks (ANN) are the most commonly used algorithms for image classification problems. An image classifier takes an image or video as input and classifies it into one of the possible categories that it was trained to identify. They are applied in various areas such as security, defense, healthcare, biology, forensics, communication, etc. There is no need to create one’s own ANN because there are several pre-trained...
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Timed rolling and rising tests in Duchenne muscular dystrophy ambulant boys: a feasibility study
PublicationBACKGROUND: Functional activities are extensively used in motor assessments of patients with Duchenne muscular dystrophy. The role of timed items has been reported as an early prognostic factor for disease progression. However, there are two functional activities that are not widely assessed in clinical practice among Duchenne muscular dystrophy patients: rolling and bed rising. This study aimed to investigate whether the 360-degree...
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Hydraulics and Pneumatics
e-Learning CoursesThe lecture covers the theoretical basics of hydraulic and pneumatic drive, simple systems encountered in practice and the elements included in these systems. Examples of applications of both types of drive in mechanical engineering are also presented, as well as their advantages and disadvantages compared to other types of drive.
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Rozprzestrzenianie się w podtorzu skutków katastrof kolejowych z udziałem materiałów niebezpiecznych
PublicationDuża część przewozów materiałów niebezpiecznych prowadzona jest koleją. W związku z tym bezpieczeństwo tych przewozów nabiera coraz większego znaczenia. Każda katastrofa z udziałem materiałów niebezpiecznych ma negatywny wpływ na uczestników tego zdarzenia oraz na otaczające środowisko, bowiem jej zasięg na ogół nie jest lokalny. Z tego wynika, że w przypadku zaistnienia katastrofy należy minimalizować jej skutki oraz w dalszych...
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Formowanie wektorów napięcia wyjściowego w pięciofazowych falownikach napięcia
PublicationW falownikach pięciofazowych, załączenie wektorów aktywnych powoduje jednoczesne formowane dwóch, zależnych od siebie wektorów napięcia wyjściowego. Sterowanie pięciofazowymi silnikami indukcyjnymi wymaga, aby wektory te miały ściśle określone długości i położenia. Niezależne formowanie dwóch wektorów napięcia o parametrach określonych w układzie sterowania silnikiem wymaga zastosowania odpowiedniej strategii Modulacji Szerokości...
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Zastosowanie modułu symulacji dynamicznej programu CAD w analizie układu napędowego elektronarzędzia
PublicationW referacie przedstawiono analizę mechanicznego układu przeniesienia napędu elektronarzędzia (wyrzynarki elektrycznej) przy zastosowaniu Modułu Symulacji Dynamicznej (MSD) programu Autodesk Inventor (AI). Opracowano modele 3D poszczególnych części elektronarzędzia i połączono je przy zachowaniu tzw. kinematyki odwrotnej. Przeprowadzono analizę wpływu poszczególnych węzłów kinetycznych na przebieg momentu na wale silnika elektrycznego....
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Charakterystyka tranzystorów z węglika krzemu w wysokosprawnych przekształtnikach
PublicationPółprzewodnikowe przyrządy mocy z węglika krzemu (SiC) osiągnęły poziom technologiczny umożliwiający powszechne stosowanie w układach przekształtnikowych. W artykule omówiono ostatnie osiągnięcia dotyczące układów przekształtnikowych z przyrządami z węglika krzemu oraz wybrane wyniki badań realizowane na Politechnice Gdańskiej. W artykule opisano właściwości statyczne i dynamiczne tranzystorów MOSFET i JFET z węglika krzemu oraz...
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POLDER AND CITY: SUSTAINING WATER LANDSCAPES ON AN URBAN EDGE
PublicationThe question investigated in this paper is how to maintain the environmental quality of the polder landscape encompassing the city in the condition of urban pressure on this landscape. On the basis of theoretical approaches, historical surveys and introductory study models new ideas are tested on the case study of Gdansk, a city located in the Vistula River delta in northern Poland. Research shows that the city was created as a...
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PRELIMINARY RESULTS FROM APPLICATION PHOSLOCK® TO REMOVE PHOSPHORUS COMPOUNDS FROM WASTEWATER
PublicationThe aim of the study is to assess the removal effectiveness of phosphorus compoundsby using lanthanum-modified bentonite. This material was produced by the Australian company Phoslock® Water Solutions Pty Ltd. According to the company, Phoslock® has substantial capacity to bound phosphate anions. The investigation was carried out in steady conditions in laboratory model with beakers. The results of the study are related to the...
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The effects of different aeration modes on ammonia removal from sludge digester liquors in the nitritation–anammox proces
PublicationThe aim of this study was to determine the impact of continuous and intermittent aeration on the rate of ammonia removal in the combined nitritation–anammox process. This process was run in two parallel sequencing batch reactors (SBRs), with a working volume V = 10 L, treating sludge digester liquors from the Gdansk (Poland) wastewater treatment plant (WWTP). The ammonia oxidizing bacteria were cultivated from activated sludge...
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Climate change impact on groundwater resources in sandbar aquifers in southern Baltic coast
PublicationShallow coastal aquifers are vulnerable hydrosystems controlled by many factors, related to climate, seawater‑freshwater interactions and human activity. Given on‑going climate change, sea level rise and increasing human impact, it is especially true for groundwater resources situated in sandbars. We developed numerical models of unsaturated zone water flow for two sandbars in northern Poland: the Vistula Spit and the Hel Spit...
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Zintegrowane sterowanie systemami zaopatrzenia w wodę pitną
PublicationOptymalne ekonomicznie zaspokojenie w miastach bieżącego zapotrzebowania na wodę pitną tak, aby spełnione były wymagania jakości dostaw oraz jakości samej wody jest złożonym zadaniem. Zarówno aspekty aplikacyjne jak i teoretyczne tego problemu są przedmiotem intensywnych prac prowadzanych w sektorach naukowych i przemysłowych na całym świecie. Prace te finansowane są przez przemysł, komitety naukowe oraz Programy Ramowe Unii Europejskiej....
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Porównanie mocy strat energetycznych w pompie wyporowej o zmiennej wydajności określonych bez uwzględnienia bądź z uwzględnieniem mocy ściskania oleju hydraulicznego
PublicationPorównano moce strat energetycznych w pompie wyporowej o zmiennej wydajności, określone bez uwzględnienia bądź z uwzględnieniem mocy ściskania oleju hydraulicznego. Ocena mocy ściskania cieczy w pompie stała się możliwa dzięki zastosowaniu, zaproponowanej przez autora, metody określenia stopnia zapowietrzenia cieczy w pompie. W metodzie określenia stopnia zapowietrzenia cieczy w pompie oraz w ocenie mocy strat objętościowych ściskania...
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Ocena stanu technicznego konstrukcji pras filtracyjnych w Grupowej Oczyszczalni Ścieków „DĘBOGÓRZE” w Gdyni
PublicationPodstawowym celem pracy była rzeczowa ocena z punktu widzenia technicznego stanu trzech pras filtracyjnych, usytuowanych w budynku, położonym w Oczyszczalni Ścieków ‘DEBOGÓRZE w Gdyni. Zakres prac obejmował szczegółowa ocenę trzech układów w każdej prasie a mianowicie: - hydraulicznego, - sterowania i automatyki, - mechanicznego – związanego ze sprawdzeniem stanu konstrukcji nośnej i obudów.. Opis i analiza stanu poszczególnych...
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Analysis of the Possibility of Using New Types of Protective Coatings and Abrasion-Resistant Linings under the Operating Conditions of the Spiral Classifier at KGHM Polska Miedź S.A. Ore Concentration Plant
PublicationA study was carried out to select the appropriate coatings for corrosion protection of the spiral classifier working at KGHM Polska Miedź S.A. Ore Concentration Plant. The abrasion resistance of selected protective coatings and wear-resistant linings was investigated using a DT-523 rotary abrasion tester with Taber CS-10 rubber abrasive discs. The average weight loss of the coatings after a cycle of 2000 revolutions was determined....
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Cycling as a Sustainable Transport Alternative in Polish Cittaslow Towns
PublicationIt is well known that growing motor traffic in urban areas causes air pollution and noise which affects the environment and public health. It is hardly surprising then that cycling should be used as an alternative mode of transport, not just in major cities but also in smaller ones including those that are members of the Cittaslow network. Their approach is based on sustainable development, care for the environment and transport...
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A Simplified SVPWM Technique for Five-leg Inverter with Dual Three-phase Output
PublicationThis article proposes a simplified space vector pulse-width modulation (SVPWM) technique five-leg inverter with dual three-phase output. An idea to fed the dual tree-phase machine by the multiphase voltage source inverters (VSIs) is not new. Dual- and multi-motor drive systems are widely used in the industry applications. The most popular fields are: electric vehicles (EVs) and traction systems. Moreover, the specific characteristic...
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ROAD SAFETY FOR CYCLISTS BASED ON THE CALORIES NEEDED
PublicationCyclists are a vulnerable group of road users, especially when no separate infrastructure for cyclists is provided. Then, road factors such as distance and altitude differences can indirectly affect cyclists' safety. Therefore, the authors proposed a procedure based on the geometric characteristics of the road that can determine riding difficulties for cyclists. The proposed procedure can be used both by the public authorities who...
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Development and test of fex, a fingers extending exoskeleton for rehabilitation and regaining mobility
PublicationThis paper presents the design process of an exoskeleton for executing human fingers' extension movement for the rehabilitation procedures and as an active orthosis purposes, together with its first clinical usability tests of a robotic exoskeleton. Furthermore, the Fingers Extending eXoskeleton (FEX) is a serial, under-actuated mechanism capable of executing fingers' extension. FEX is based on the state-of-art FingerSpine serial...
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Human memory enhancement through electrical stimulation in the temporal cortex
PublicationDirect electrical stimulation of the human brain can elicit sensory and motor perceptions as well as recall of memories. Stimulating higher order association areas of the lateral temporal cortex in particular was reported to activate visual and auditory memory representations of past experiences (Penfield and Perot, 1963). We hypothesized that this effect could be used to modulate memory processing. Recent attempts at memory enhancement...
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An overview of the strategies for the deammonification process start-up and recovery after accidental operational failures
PublicationThe deammonification process has been universally acknowledged as an energy-efficient technology for sewage disposal. In contrast with traditional biological nitrogen removal technology, the deammonification process is able to remove ammonia from wastewater with the simplest nitrogen removal process because of its advantages of lower operating expenses, no organic carbon consumption, lower biomass production, lower carbon dioxide...
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The long-term properties of mineral-cement-emulsion mixtures
PublicationThis publication presents evaluation of long-term behavior of mineral-cement-emulsion (MCE) mixtures. MCE mixtures are among the major products of cold recycling of old asphalt pavements. They are composed by binding of the old materials reclaimed from the pavement and new mineral aggregate using two different binding agents – cement and bituminous emulsion. While bituminous emulsion dissolutes and binds materials quite fast, it...
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Nitrification, denitrification, and dephosphatation capability of activated sludge during co-treatment of intermediate-age landfill leachates with municipal wastewater
PublicationThis study focuses on the possible use and efficacy of the co-treatment of landfill leachate (intermediate-age) with municipal wastewater. The nitrification, denitrification, and dephosphatation capability of activated sludge acclimated with a mixture of raw municipal wastewater (RWW) with gradually increasing amounts of raw landfill leachate (RLL) (from 0.5 to 5% v/v) were tested. Biochemical tests were conducted simultaneously...
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Design and experimental investigations of a cylindrical microjet heat exchanger for waste heat recovery systems
PublicationCompact heat exchangers have more and more applications in many areas, including the HVAC, food and petrochemical industry. This paper describes the development of heat exchanger technology for waste heat recovery (WHR) from a range of processes. Case-study testing shows that the proposed heat exchanger can successfully enhance heat transfer and recover waste heat in a range of applications making them economically, environmentally and...
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Mobile inventory system for hydrotechnical objects using data from multiple sensors operating simultaneously
PublicationThe knowledge of the location, shape and other characteristics of spatial objects in the coastal areas has a significant impact on the functioning of ports, shipyards, and other water-infrastructure facilities, both offshore and inland. Therefore, measurements are taken of the underwater part of the waterside zone, which means the bottom of water and other underwater objects (e.g. breakwaters, docks, etc.), and objects above the...
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Application of subsurface vertical flow constructed wetlands to reject water treatment in dairy wastewater treatment plant
PublicationThe paper presents the effects of applying subsurface vertical flow constructed wetlands (SS VF) for the treatment of reject water generated in the process of aerobic sewage sludge stabilization in the biggest dairy wastewater treatment plant (WWTP) in Poland. Two SS VF beds were built: bed (A) with 0.65 m depth and bed (B) with 1.0 m depth, planted with reeds. Beds were fed with reject water with hydraulic load of 0.1 m d-1 in...