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Search results for: environmental protection engineering
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How to guide photocatalytic applications of titanium dioxide co-doped with nitrogen and carbon by modulating the production of reactive oxygen species
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PROBLEMS OF COLLISIONS BETWEEN ADJACENT STEEL STRUCTURES UNDER EARTHQUAKE EXCITATION
PublicationNowadays, the high level of urbanization forces the engineers to design closely-separated structures and to take into account many factors influencing their response, including collisions between them due to insufficient separation distance during moderate to strong ground motions. Recent observations as well as experimental and numerical investigations have confirmed that interactions...
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Strength parameters of masonry walls in modelling historic constructions
PublicationThe paper presents the determination of the basic material properties of a historic brickwork. Experimental studies were used to identify the basic material properties of bricks. The mechanical properties of the masonry, as an orthotropic homogenized material, were calculated. Then, numerical simulations using the Finite Element Method (FEM) were performed to verify the experimental outcomes. Macromodels with element sizes of 40,...
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SORPTION OF SELECTED CHLORINATED SOLVENTS ON PLANT DEBRIS COLLECTED IN A CITY PARK
PublicationDebris from deciduous trees in the form of park green waste was investigated as a potential biosorbent for the removal of chlorinated solvents from water. The sorption properties of beech leaves and cupules, oak leaves and acorns, birch leaves and lime leaves (all tree species common for a moderate climate) in a non-modified form were investigated with regard to the removal of perchloroethylene, 1,1,2-trichloroethane and 1,1,1,2-tetrachlorothane....
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Temperature Impact of Nitrogen Transformation in Technological System: Vertical Flow Constructed Wetland and Polishing Pond
PublicationThe article describes the results of the research, purpose of which was to evaluate influence of the temperature on the effectiveness of nitrification and denitrification in the sewage treatment system consisting of vertical flow constructed wetland and polishing pond. During the analysed period, the efficiency of removing total nitrogen was low and amounted to 12.7%. In the polishing pond in the summer period, content of total...
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The effect of nonlinear restraint on torsional buckling and post-buckling behaviour of a thin-walled column
PublicationW pracy rozważa się wyboczenie skrętne i zachowanie pokrytyczne osiowo ściskanego swobodnie podpartego pręta cienkosciennego o przekroju otwartym ze sprężytą nieliniową podporą w środku rozpietości. Rozwiązanie problemu wyznaczono za pomocą metody małego parametru. W przykładzie numerycznym wyznaczono siłę krytyczną i ścieżkę początkowego zachowania pokrytycznego dwuteowego pręta z podporą sprężystą o charakterystyce składającej...
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Removal of Pharmaceutically Active Compounds in Sequencing Batch Reactor
PublicationIn recent years, considerable attention was paid to the presence of organic micro-pollutants such as Active Pharmaceutical Ingredients (API) in the aquatic environment due to their negative impact on public health and aquatic ecosystems. Numerous papers have pointed out API presence as common constituents of effluents from Wastewater Treatment Plants (WWTPs). This is the result of various efficiencies of API removal by conventional...
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VIBRATION PROBLEMS OF AN EXAMPLE OF TEMPORARY STEEL GRANDSTAND UNDER HUMAN-INDUCED EXCITATION
PublicationLighter and slender structural members of a typical grandstand leads to a significant reduction in the frequencies, that is why such structures are more easily induced to vibrations. The aim of the present paper is to show the results of our experimental studies and the numerical analyses, focused on the behaviour of a part of a typical temporary steel grandstand under dynamic loads. The peak values of accelerations of a steel...
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Experimental Study on Steel Tank Model Using Shaking Table/ Badania Eksperymentalne Modelu Zbiornika Stalowego Na Stole Sejsmicznym
PublicationStalowe zbiorniki walcowe są bardzo popularnymi konstrukcjami używanymi do magazynowania produktów przemysłu chemicznego i naftowego. Ich bezpieczeństwo i niezawodność są kluczowe, ponieważ każde uszkodzenie może nieść za sobą bardzo poważne konsekwencje. Trzęsienia ziemi są najbardziej niebezpiecznymi, a zarazem najbardziej nieprzewidywalnymi obciążeniami dynamicznymi, które mogą oddziaływać na tego typu konstrukcje. Z drugiej...
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Construction solutions for historical object foundations in the context of changing their functional use
PublicationProperly executed renovation and adaptation of a grade listed property not only ensures its constructional safety, but may also highlight the object’s historical value. Taking into consideration various factors, such as divergence of interests, or technical and legal determinants, it is safe to say that the renovation and adaptation of grade listed properties for new purposes is a complex process. The authors of the paper wish...
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Thermally activated natural chalcopyrite for Fenton-like degradation of Rhodamine B: Catalyst characterization, performance evaluation, and catalytic mechanism
PublicationIn this work, catalytic activity of natural chalcopyrite (CuFeS2) was improved by thermal activation. The modified chalcopyrite was used as efficient catalyst for degradation of organic dye Rhodamine B (RhB) through advanced oxidation process (AOP). Effects of catalyst dosage, H2O2 concentration, reaction temperature, solution pH, anions, and natural organic matter on the degradation efficiency of RhB were investigated. This study...
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Carbon nitride exfoliation for photocatalysis and photocatalytic ozonation over emerging contaminants abatement
PublicationThe production of graphitic carbon nitride was studied with the addition of a following exfoliation step using ultrasounds, at different times. The treatment produced catalysts with much higher surface areas, from 2.18 m2 g 1 with no treatment to 28.34 m2 g 1 after 36 h of exfoliation. During exfoliation, melem was also produced, and may further enhance the photoluminescence and photocatalytic properties. The photocatalytic reaction...
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Removal of phenolic inhibitor compounds from hydrolysates and post-fermentation broths by using a Hydrophobic Magnetic Deep Eutectic Solvent
PublicationHydroxymethylfurfural (HMF), furfural (FF), hydroquinone (HQ), and vanillin (VAN) are among the main inhibitors generated during most of biomass pre-treatments prior to fermentation processes. They are recognized as toxic to several fermentative microorganisms and therefore cause a decrease in biohydrogen or biofuel production (after hydrolysis). Moreover, if they are released into aqueous solutions (after fermentation), they can...
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Comparison of Average Energy Slope Estimation Formulas for One-dimensional Steady Gradually Varied Flow
PublicationTo find the steady flow water surface profile, it is possible to use Bernoulli’s equation, which is a discrete form of the differential energy equation. Such an approach requires the average energy slope between cross-sections to be estimated. In the literature, many methods are proposed for estimating the average energy slope in this case, such as the arithmetic mean, resulting in the standard step method, the harmonic mean and...
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Impact of Urbanization on Stormwater Runoff from a Small Urban Catchment: Gdańsk Małomiejska Basin Case Study
PublicationThis paper deals with the impact of different forms of urbanization on the basin outflow. The influence of changes in land cover/use, drainage system development, reservoirs, and alternative ways of stormwater management (green roofs, permeable pavements) on basin runoff was presented in the case of a small urban basin in Gdańsk (Poland. Seven variants of area development (in the period of 2000-2012) – three historical and four...
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Evaluation of antimicrobial activities of powdered cuttlebone against Klebsiella oxytoca, Staphylococcus aureus, and Aspergillus flavus
PublicationBackground: The presence of medicines in the environment is considered as a serious threat to the human health. The entrance of these substances into the water sources causes soil pollution, which eventually leads to the environmental pollution and it creates some problems for the public health. Also, increasing antibiotic resistant bacteria has attracted the attention of researchers to the use of natural resources such as marine...
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Estimation of Stresses in a Dry Sand Layer Tested on Shaking Table
PublicationTheoretical analysis of shaking table experiments, simulating earthquake response of a dry sand layer, is presented. The aim of such experiments is to study seismic-induced compaction of soil and resulting settlements. In order to determine the soil compaction, the cyclic stresses and strains should be calculated first. These stresses are caused by the cyclic horizontal acceleration at the base of soil layer, so it is important...
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Lax-Wendroff and McCormack Schemes for Numerical Simulation of Unsteady Gradually and Rapidly Varied Open Channel Flow
PublicationTwo explicit schemes of the finite difference method are presented and analyzed in the paper. The applicability of the Lax-Wendroff and McCormack schemes for modeling unsteady rapidly and gradually varied open channel flow is investigated. For simulation of the transcritical flow the original and improved McCormack scheme is used. The schemes are used for numerical solution of one dimensional Saint-Venant equations describing free...
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Impact of Energy Slope Averaging Methods on Numerical Solution of 1D Steady Gradually Varied Flow
PublicationIn this paper, energy slope averaging in the one-dimensional steady gradually varied flow model is considered. For this purpose, different methods of averaging the energy slope between cross-sections are used. The most popular are arithmetic, geometric, harmonic and hydraulic means. However, from the formal viewpoint, the application of different averaging formulas results in different numerical integration formulas. This study...
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Modal Analysis of a Steel Radial Gate Exposed to Different Water Levels
PublicationWith the increase in water retention needs and planned river regulation, it might be important to investigate the dynamic resistance of vulnerable elements of hydroelectric power plants, including steel water locks. The most frequent dynamic loads affecting hydroengineering structures in Poland include vibrations caused by heavy road and railway traffic, piling works and mining tremors. More destructive dynamic loads, including...
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Simplified probabilistic analysis of settlement of cyclically loaded soil stratum using point estimate method
PublicationThe paper deals with the probabilistic analysis of settlement of a non-cohesive soil layer subjected to cyclic loading. Originally, the settlement assessment is based on deterministic compaction model which requires integration of a set of differential equations. However, making use of the Bessel functions the settlement of the soil stratum can be calculated by means of simplified algorithm. The compaction model parameters were...
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A RECONNAISSANCE-SCALE GIS-BASED MULTICRITERIA DECISION ANALYSIS TO SUPPORT SUSTAINABLE BIOCHAR USE: POLAND AS A CASE STUDY
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Experimental Verification of Storm Sewer Transient Flow Simulation
PublicationThe paper focuses mainly on laboratory investigations of transient and transcritical flow in a single pipe of a sewer system. The aim of this paper is to present a comparison between pressure values calculated by an improved McCormack scheme and those measured at the hydraulic laboratory of the Gdansk University of Technology, which were observed inside a pipe in an experiment for water flow with pressurization. The analysis proves...
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Experimental Determination of Limit Adhesive Shear Strtess between Solid Wall and Liquid
PublicationTheoretically slip of a fluid with respect to the solid wall should occur even at a very low velocity of motion. However theoretical analysisand some empirical data suggest that there must be a limit value of shear stress, below which the slip does not appear. A simple metyhod of this stress determination was proposed in the paper.
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Modelling of FloodWave Propagation with Wet-dry Front by One-dimensional Diffusive Wave Equation
PublicationA full dynamic model in the form of the shallow water equations (SWE) is often useful for reproducing the unsteady flow in open channels, as well as over a floodplain. However, most of the numerical algorithms applied to the solution of the SWE fail when flood wave propagation over an initially dry area is simulated. The main problems are related to the very small or negative values of water depths occurring in the vicinity of...
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Problem of Clogging in Drainage Systems in the Examples of the Zur and Podgaje Dams
PublicationDrainage plays an extremely important role in hydraulic structures, such as earth dams. Observations of drainage in hydraulic structures under various soil conditions indicate that the phenomenon of clogging can lead to a radical reduction in the efficiency of drainage, making it non-functional within a few years after construction. This article describes the problems of drainage clogging by iron oxide in the examples of the Zur...
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Numerical Simulations and Tracer Studies as a Tool to Support Water Circulation Modeling in Breeding Reservoirs
PublicationThe article presents a proposal of a method for computer-aided design and analysis of breeding reservoirs in zoos and aquariums. The method applied involves the use of computer simulations of water circulation in breeding pools. A mathematical model of a pool was developed, and a tracer study was carried out. A simplified model of two-dimensional flow in the form of a biharmonic equation for the stream function (converted into...
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Outlet Flow Velocity In Circular Culvert
PublicationThe outlet flow velocity in the end section of the culvert barrel depends in most cases on the culvert geometry, including the barrel slope, as well as on upstream and downstream channel parameters. Flowing water can create pressure flow or free surface flow in the culvert barrel. In the case of an unsubmerged barrel outlet, the free-surface flow is more frequent than the full flow. Increased velocities can cause channel bed scour...
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Velocity Field Characteristics at the Inlet to a Pipe Culvert
PublicationA poorly designed culvert inlet structure causes scouring, which can lead to the collapse of the culvert and significant damage to the neighboring land. A set of laboratory tests was evaluated to examine velocity distribution at the culvert inlet. A three-dimensional acoustic Doppler velocimeterwas used to measure instantaneous flowvelocity upstream of the culvert. The analysis of mean velocities, turbulence strength, and Reynolds...
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Whirling system of water exchangein breeding pools
PublicationTo secure the proper conditions of life for sea mammals existing in closed systems one has to maintain the character of the breeding basins (i.e. shape, dimensions, facing of walls and bottom, quality and motion of water) as natural as possible. An appropriate system of water exchange plays a very important role here. A full renewal of water is time-consuming, expensive and troublesome, so can be made only periodically, and should...
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Microplastics in atmospheric dust samples of Sistan: sources and distribution
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Penetration resistance of Lubiatowo sand in calibration chamber tests
PublicationAnaliza oporu na wciskanie na stożku sondy statycznej wciskanej na podstawie badań modelowych w komorze kalibracyjnej z kontrolą naprężeń bocznych. Przeprowadzono badania z zastosowaniem standardowej końcówki CPT, dylatometru DMT, mini-stożka CPT oraz pali modelowych o różnej średnicy. Badania wykonano na piasku modelowym z plaży w Lubiatowie w stanie średnio zagęszczonym i zagęszczonym w szerokim zakresie składowej pionowej naprężenia....
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Viscoelastic model of waterhammer in single pipeline - problems and questions
PublicationW artykule dokonano analizy zastosowania lepkosprężystego modelu uderzenia hydraulicznego w pojedynczym przewodzie. Przedstawiono teoretyczne podstawy lepkosprężystego zachowania się materiału przewodu oraz matematyczny opis modelu uderzenia hydraulicznego w rurociągu z tworzywa sztucznego. Przedyskutowano główne problemy pojawiające się przy aplikacji takiego modelu. Nacisk położono na identyfikację parametrów modelu. Przeanalizowano...
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Characteristics of tyre chips-sand mixtures from triaxial tests
PublicationAnaliza parametrów wytrzymałościowych i odkształcalności mieszanek piasku i kawałków zużytych opon. Powtórne użycie tego materiału, odpowiednio przetworzonego na skrawki i elementy o kształcie kołowym pozwala po odpowiednim zmieszaniu z gruntem niespoistym na uzyskanie materiału o zwiększonej wytrzymałości na ścinanie zachowywanej również przy dużych odkształceniach. Analizowano mieszanki o różnej zawartości opon przy naprężeniach...
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The influence of changes of soil parameters due to consolidation on the interaction of piles and soft soil layer
PublicationZaprezentowano problem wyznaczania bocznego parcia gruntu o małej wytrzymałości na pale. Opisano przypadki występowania bocznego obciążenia pali. Scharakteryzowano właściwości i zachowanie gruntów słabych stanowiących warstwę podłoża o małej wytrzymałości. Zaprezentowano propozycje obliczania bocznego parcia według różnych autorów. Przedstawiono wpływ konsolidacji na zmianę wytrzymałości gruntów słabych w czasie oraz na obliczanie...
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Size effect in centrifuge cone penetration tests
PublicationOkreślenie efektu skali w badaniu wciskania stożka w zagęszczonych piaskach kwarcowych na podstawie badań modelowych w wirówce geotechnicznej. Badania przeprowadzono na dwóch piaskach kwarcowych przy przyśpieszeniach od 30g do 100g. Analizowano efekt skali związany ze stosunkiem średnicy modelu (mini-stożka) do średniej średnicy ziaren oraz wpływem poziomu naprężenia na opór stożka. Wpływ poziomu naprężenia powoduje powstanie geometrycznego...
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Comprehensive circumscribing of non-linearity cases of a water supply system with smooth flow control
PublicationW artykule opisano formalnie poprawne metody opisu matematycznego pracy pomp o płynnie regulowanych wydatkach oraz reduktorów ciśnienia i reduktorów przepływu w modelowaniu przepływów ustalonych zachodzących w systemach wodociągowych. Opisano metodę opartą o dynamiczną analizę wrażliwości systemu oraz metodę wykorzystującą charakterystyki hydrauliczne systemu wodociągowego. Przedstawiono wyniki symulacji wykorzystującej ww. metody...
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Hydraulic loss coefficients in 1D Flows
PublicationWyniki pomiarów pokazują, że współczynniki strat energii mechanicznej dla przepływów niejednostajnych i nieustalonych przyjmują wartości zdecydowanie większe, niż tradycyjnie przyjmowane dla ruchu jednostajnego. W pracy przedstawiono ananizę możliwych przypadków ruchu oraz wyniki obserwacji laboratoryjnych.Wykazano, że wzrost wartości współczynników jest uzasadniony fizykalnie.Zaproponowano robocza metodą ich korygowania.
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Influence of dissolved organic matter in natural and simulated water on the photochemical decomposition of butylparaben
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Effect of water infiltration through concrete block spillways on the slope stability of earth overflow dams
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Hydraulic transients analysis in pipe networks by the method of characteristics (MOC)
PublicationW pracy przedstawiono wyniki badań eksperymentalnych i analizy numerycznej zjawiska przepływów nieustalonych w przewodach pojedynczych oraz symulacji numerycznych w sieci pierścieniowej. Model matematyczny stanowi układ dwóch równań różniczkowych cząstkowych typu hiperbolicznego, które rozwiązano za pomocą metody charakterystyk. Badania eksperymentalne przeprowadzono na modelu w skali laboratoryjnej. Uzyskano dobrą zgodność obliczeń...
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Two-dimensional vertical Reynolds-averaged naviers-stokes equations versus one-dimensional Saint-Venant model for rapidly varied open channel water flow modelling
PublicationPrzedstawiono dwa modele przepływu wody ze swobodną powierzchnią -płaski pionowy model Reynoldsa i model de Saint-Venanta.Do rozwiązania równań pierwszego modelu zastosowano schemat SIMPLE oraz wykorzystano metodę cząstek znaczonych MAC do wyznaczania swobodnej powierzchni wody. Równania Saint-Venanta rozwiązano metodą objętości skończonych. Obydwa modele zastosowano do symulacj zjawiska typu katastrofa zapory. Porównano wyniki...
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Flood Routing by the Non-Linear Muskingum Model: Conservation of Mass and Momentum
PublicationIn this paper, the conservative properties of the Muskingum equation, commonly applied to solve river flood routing, are analysed. The aim of this analysis is to explain the causes ofthe mass balance error, which is observed in the numerical solutions of its non-linear form. The linear Muskingum model has been considered as a semi-discrete form of the kinematic wave equation and therefore it was possible to derive its two non-linear...
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Representation of a built-up area in the numerical simulation of urban flash flooding
PublicationPrzedstawiono wyniki modelowania powodzi miejskiej przy pomocy dwuwymiarowych równań de Saint-Venanta. Równania rozwiązano metodą objętości skończonych. Zaprezentowano dwie techniki reprezentacji obszarów zabudowanych w numerycznej symulacji powodzi - bezpośrednie wykluczenie budynków z siatki numerycznej oraz zastąpienie grup budynków terenami o znacznie zwiększonej szortkości powierzchni. W celu oceny wykorzystanych metod wykonano...
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Comparison of sono-direct and sono-alternate current electro-coagulation processes for removal of color and turbidity from domestic wastewater
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An integrated approach to optimization of fermentation conditions for bioethanol production from local leftover Injera waste using central composite design
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Optimization and evaluation of the process variable’s effect on color and turbidity removal from coffee processing wastewater: Using a photoelectrochemical oxidation process
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Numerical Analysis of Turbulent Flow over a Backward-facing Step in an Open Channel
PublicationComputational examinations of the flow field in an open channel having a single Backward--Facing Step (BFS) with a constant water depth of 1.5 m were performed. The effects of the expansion ratio, and the flow velocity along the reattachment length, were investigated by employing two different expansion ratios of 1.5 and 2, and eight various flow velocities of 0.5, 1, 2, 3, 4, 5, 7.5 and 10 m/sec in the Computational Fluid Dynamic...
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Negative impact of constant RPM control strategy on ship NOx emission in waves
PublicationIn severe wave conditions, the ship propulsion system is loaded with high fluctuations due to external disturbances. The highly fluctuating loads enforce radical changes in the main engine torque, which in turn demands variation of the fuel rate injected into the cylinders if a constant rotational speed strategy is applied. Therefore, the temperature of gases varies to a large extent during the combustion process in the cylinders....
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Synthesis, characteristics, and photocatalytic activity of zinc oxide nanoparticles stabilized on the stone surface for degradation of metronidazole from aqueous solution
PublicationAbstract Background: The presence of antibiotics such as metronidazole in wastewater even at low concentrations requires searching for a suitable process such as advanced oxidation process (AOP) to reduce the level of pollutants to a standard level in water. Methods: In this study, zinc oxide (ZnO) nanoparticles were synthesized by thermal method using zinc sulfate (ZnSO4) as a precursor, then, stabilized on stone and was used...