Repozytorium publikacji - Politechnika Gdańska

Ustawienia strony

english
Repozytorium publikacji
Politechniki Gdańskiej

Pokaż publikacje z roku

Publikacje z roku 2022

Pokaż wszystkie
  • Application of the ISE Optimized Proportional Control of the Wave Maker in a Towing Tank
    • Marcin Drzewiecki
    • Jarosław Guziński
    2022 Pełny tekst IEEE Access

    This paper presents the improvement of the wave maker control system. The wave maker is a facility widely used in hydromechanics laboratories to generate waves in towing tanks. It is equipped with an electrohydraulic drive and an actuator submerged into water. The waves are generated to model the environmental conditions for physical experiments, performed on reduced-scale models of maritime objects. The physical experiments allow to predict the behaviour of full-scale objects and prove the results of numerical analyses. The overriding goal of the fluid dynamics experiments is to improve the human safety and survivability of constructions. The reported investigation and application works were vital for the improvement of physical model tests. The optimization of the proportional controllers was performed in terms of the Integral of Squared Error (ISE). The final evaluation was performed in terms of the frequency response characteristic. The results of the proportional control optimization were evaluated versus the previously applied control. The experimental research was conducted in the real towing tank located at the Maritime Advanced Research Centre. The investigation has shown the advantage of the ISE optimized conventional proportional control. It has particularly proven the affordability and swiftness of the optimization process. It also proved a more efficient frequency response of the wave maker obtained within a required and reasonable lead time. The performed investigation has greatly contributed to the development of a new method of physical experiments in white noise waves. The results related to this new more efficient method are presented as well.

  • Application of Traction Supply System for Charging Electric Cars
    • Mikołaj Bartłomiejczyk
    • Leszek Jarzębowicz
    • Roman Hrbáč
    2022 Pełny tekst ENERGIES

    The development of electromobility involves the development of electric cars charging infrastructure. The increase of the number of chargers poses new demands for the AC power grid, especially in regard to its capacity of delivering high peak power. As an alternative for the public AC power grid, urban electrified transportation systems (trams, trolleybuses, and metro) can be used for supplying electric cars chargers. The article discusses four options of integrating electric cars chargers with a traction power supply system. The option of connecting the charger to the traction overhead supply line has been selected due to the spatial availability of the power source and possibility to use regenerative braking energy for charging. A set of criteria has been developed for analysing the capability of the traction supply system to feed electric cars chargers. An exemplary feasibility analysis was carried out for trolleybus traction supply system in Gdynia, Poland. The impact of installing the charging station on specific traction supply parameters has been predicted using present-state recordings of electrical parameters and assumed charging station power. The study shows that every supply section of the considered trolleybus traction system has the capability of installing a fast-charging station, which provides opportunities of expanding the charging stations network in Gdynia.

  • APPLICATION POSSIBILITIES OF THE S960 STEEL IN UNDERWATER WELDED STRUCTURES
    • Jacek Tomków
    • Michał Landowski
    • Grzegorz Rogalski
    2022 Pełny tekst Facta Universitatis-Series Mechanical Engineering

    In this paper, the application possibilities of the ultra-high strength (UHSS). Domex 960 steel in the underwater welded structures are analyzed. In the research, the investigated material has been tested in bead-on-plate wet welding conditions with the usage of different heat input values, namely 0.63 kJ/mm, 0.72 kJ/mm and 0.93 kJ/mm. Specimens were performed by the manual metal arc (MMA) welding method with the usage of rutile covered electrodes. Firstly, the nondestructive visual testing (VT) was carried out. In the next step, the metallographic macro- and microscopic tests were performed. Finally, the hardness of the weld metal and heat-affected zone (HAZ) was measured by the Vickers HV10 method. The performed experiments allow the statement that the Domex 960 steel could be welded in a water environment. It also showed that increasing heat input leads to decreasing the hardness in HAZ by 30 HV10. It may result in decreasing the susceptibility to cold cracking during butt- and filet welding in the water environment.

  • Architectural and Urban Planning Solutions for the Protection of Heritage Buildings in the Context of Terrorist Attacks: Following the Example of Passive Protection Systems
    • Karol Grębowski
    • Aleksandra Wróbel
    2022 Pełny tekst Buildings

    Events in recent years showing numerous terrorist attacks raise awareness regarding the neces-sity of considering the safety of heritage buildings. The analysis of available data allows us to conclude that it is not possible to fully prevent terrorist attacks. On the other hand, it is possible to minimize the impact of such incidents through proper design of Passive Protection System (PPS) components. One possible architectural solution to be deployed as a passive defense system is laminated glass panel walls. The study presented in the article is innovative, considering there are no current standard documents or recommendations to determine the conditions of destruc-tion as well as the methods of testing the strength of glass components used in laminated glass panel walls under vehicle impact. The present work represents the material used in PVB inter-layers using the Mooney-Rivlin constitutive model, which correctly describes the non-linear characteristics of PVB. Based on the obtained results, new parameters of PVB laminated glass ex-posed to vehicle impact were developed. The newly developed parameters underwent quality verification through a comparison of results from experimental studies and digital simulations. Finally, the strength of laminated glass panel wall was subject to evaluation, considering the amount and thickness of individual VSG glass layers and the number of PVB interlayers at ground floor level of a heritage building with high susceptibility to terrorist attacks. The newly developed parameters of laminated glass may be implemented as a premade input .mat file for the material available in the KEYWORD database under the name MAT_32-LAMINATED_GLASS in LS-DYNA software.

  • Architectural Space of Ideas in the Author’s Structures Presented at the Fire Painted Images Art Festival: A Case Study
    • Agnieszka Kurkowska
    2022 Pełny tekst Loci Communes

    The article is aimed to discuss the place of architecture in the space of ideas. The present work discusses a specific place, the Zaspa housing estate in Gdańsk, and refers to a specific person, namely, the author of artistic installations tem- porarily exhibited in the Zaspa housing estate. Also, the wider context of the specific situations in which the exhibitions were displayed is presented. The article attempts to answer the question of the importance of the quality of dwelling in the context of the quality of life of city dwellers. The work focuses on the subjective quality of life, identified most often with the feeling of satisfaction with life in its various aspects and with mental well-being. The quality of living, in turn, may be defined as satisfaction with the structure and functioning of the house and its commonly shared surroundings that constitutes the context of such living. The installations exhibited in the Zaspa estate discussed in the following article represent a potential area for activities with which to change the landscape and/or architectural elements of housing estates that refer to the living space. The essence of the research lies in the analysis of the place architecture occupies in a wider context of the intangible spaces. Homes can be perceived in a phenomenological way. It this case, the spaces of the house are inside us, just as we are inside them (Bachelard, 1994).

  • Architecture Design of a Networked Music Performance Platform for a Chamber Choir
    • Jan Cychnerski
    • Bartłomiej Mróz
    2022 Pełny tekst Communications in Computer and Information Science

    This paper describes an architecture design process for Networked Music Performance (NMP) platform for medium-sized conducted music ensembles, based on remote rehearsals of Academic Choir of Gdańsk University of Technology. The issues of real-time remote communication, in-person music performance, and NMP are described. Three iterative steps defining and extending the architecture of the NMP platform with additional features to enhance its utility in remote rehearsals are presented. The first iteration uses a regular video conferencing platform, the second iteration uses dedicated NMP devices and tools, and the third iteration adds video transmission and utilizes professional low-latency audio and video workstations. For each iteration, the platform architecture is defined and deployed with simultaneous usability tests. Its strengths and weaknesses are identified through qualitative and quantitative measurements – statistical analysis shows a significant improvement in rehearsal quality after each iteration. The final optimal architecture is described and concluded with guidelines for creating NMP systems for said music ensembles.

  • Architektura kościołów dominikańskich w średniowiecznych Prusach
    • Piotr Samól
    2022

    Badania architektoniczne kościołów w Chełmnie, Elblągu, Gdańsku i Tczewie oraz próba rozpoznania danych na temat świątyni predykantów w Toruniu pozwoliły zrekonstruować historię budowlaną pięciu z nich. Poszczególne obiekty nigdy nie były realizowane w całości według z góry założonego planu. Proces ich projektowania i budowy to aż do przełomu XIV i XV wieku ciągłe modyfikacje, wpasowywanie się w kontekst przestrzenny miasta, zmiany potrzeb dominikanów. Jest znamienne, że niesamowicie intensywny pod względem prac budowlanych okres około 150 lat (ok. 1250 r. – ok. 1400 r.) zakończył się w czasie kryzysu gospodarczego i ideologicznego, który pojawił się w Prusach (i w instytucjach z nimi związanych) po przegranej „wielkiej wojnie” (l. 1409–1411) z Polską i Litwą. Skupienie się na niewielkich naprawach w obrębie kościołów i klasztorów w pierwszej połowie XV wieku wskazuje na silny wpływ kondycji gospodarczo-społecznej na życie zakonów żebraczych. Wraz z rozwojem demograficznym miast i wzrostem liczby zakonników dominikanie decydowali się na powiększanie swoich obiektów w części przeznaczonej dla wiernych. Dominikanie w średniowiecznych Prusach, otrzymując parcelę w nowo lokowanym mieście, wznosili swoją pierwszą świątynię w taki sposób, żeby umożliwić dalszą jej rozbudowę. Tak usytuowano kościoły w Chełmnie, Elblągu, Tczewie i Toruniu. Próba syntezowania i usystematyzowania architektury kościołów dominikańskich w Prusach była możliwa dzięki wieloletnim badaniom terenowym połączonym z analizą licznej literatury konfrontowanej z rozpoznanymi źródłami historycznymi i archeologicznymi. Świadomie ograniczono stosowanie metody porównawczej, wychodząc z założenia, że jej użycie jest możliwe dopiero wówczas, gdy znamy historię budowlaną poszczególnych obiektów, popartą materialnymi dowodami. Badania czterech średniowiecznych obiektów zachowanych do dziś i analiza jednego istniejącego jedynie w partii fundamentów pozwoliły zbudować bazę około trzydziestu zrekonstruowanych etapów i faz umiejscowionych chronologicznie. Stanowiła ona podstawę do rozpoznania schematów rozwojowych, którymi kierowali się dominikanie prowadzący prace budowlane przy swoich świątyniach. Takie podejście pozwala lepiej powiązać historię architektury z kontekstem społecznym, gospodarczym i przestrzennym, w jakim działali dominikanie. Ich obecność w miastach związana była wszak już z procesem lokacji, a dzieje świątyń są odbiciem nie tylko rozwoju urbanistycznego, ale i losów całego ośrodka.

  • Architektura proekologiczna: edukacja po dyplomie. Studia podyplomowe na Wydziale Architektury Politechniki Gdańskiej
    • Katarzyna Zielonko-Jung
    • Robert Idem
    2022 Architektura & Biznes

    Artykuł jest zawiera refleksji na temat edukacji architektów w Polsce w zakresie zrównoważonego rozwoju i zagadnień proekologicznych. Analizując program studiów oraz sposób nauczania na wydziałach architektury w Polsce, zauważyć można niedosyt treści programowych związanych z całościowym podejściem do tej problematyki. Brak też wypracowanych, powszechnych wzorców takiego podejścia w praktyce architektonicznych pracowni projektowych. Wiedzy w tym zakresie brak także architektom-urzędnikom opracowującym dokumenty planistyczne, współdecydującym o nowych inwestycjach i przekształceniach zabudowy istniejącej. Celem artykułu jest prezentacja założeń programowych studiów podyplomowych "Architektura proekologiczna" prowadzonych na Wydziale Architektury Politechniki Gdańskiej. Pierwsza edycja studiów uzyskała znaczne dofinansowanie Wojewódzkiego Funduszu Ochrony Środowiska i Gospodarki Wodnej w Gdańsku, który m.in. dzięki doświadczeniu budowy swojej nowej siedziby jako budynku energoaktywnego o wysokich standardach środowiskowych – docenił jak złożonym procesem jest projektowanie takich obiektów i jak wielu nowych kompetencji wymaga od architektów. Dofinansowanie pierwszej edycji studiów podyplomowych pozwoliło na staranne przygotowanie programu i pozyskanie kadry wykładowców z różnych ośrodków z Polski i zagranicy. W artykule zaprezentowano program studiów oraz podsumowano dotychczasowe efekty kształcenia.

  • Architektury klasyfikatorów obrazów
    • Konrad Zawora
    2022

    Klasyfikacja obrazów jest zagadnieniem z dziedziny widzenia komputerowego. Polega na całościowej analizie obrazu i przypisaniu go do jednej lub wielu kategorii (klas). Współczesne rozwiązania tego problemu są w znacznej części realizowane z wykorzystaniem konwolucyjnych głębokich sieci neuronowych (convolutional neural network, CNN). W tym rozdziale opisano przełomowe architektury CNN oraz ewolucję state-of-the-art w klasyfikacji obrazów na przestrzeni lat 2014--2021. Łącznie opisano 28 topologii głębokich konwolucyjnych sieci neuronowych, należących do 7 rodzin: EfficientNet, ResNet, DenseNet, Inception, NasNet, MobileNet oraz VGG.

  • Are Pair Trading Strategies Profitable During COVID-19 Period?
    • Muhammad Khalid Sohail
    • Abdul Raheman
    • Javid Iqbal
    • Muzammal Ilyas Sindhu
    • Abdul Staar
    • Muhammad Mushafiq
    • Humaira Afzal
    2022 Journal of Information & Knowledge Management

    Pair trading strategy is a well-known profitable strategy in stock, forex, and commodity markets. As most of the world stock markets declined during COVID-19 period, therefore this study is going to observe whether this strategy is still profitable after COVID-19 pandemic. One of the powerful algorithms of DBSCAN under the umbrella of unsupervised machine learning is applied and three clusters were formed by using market and accounting data. The formation of these three clusters was based on book value per share, earning per share, classification of sector, market capitalisation and with other factors formed from PCA on the returns of daily data of six months of the 80 sample firms for year 2019–2020. An average of 0:32% average excess monthly return with Sharpe ratio of 0:0012 and Treynor ratio of 0:0231 is to be observed in COVID-19 pandemic period. However, the result of risk-adjusted performance under Jensen's alpha is observed to be insignificant. The policy implication of this study, for different portfolios and fund managers is suggested to use machine learning approach to get positive and higher returns for their clients

  • ARIMA vs LSTM on NASDAQ stock exchange data
    • Dariusz Kobiela
    • Dawid Krefta
    • Weronika Król
    • Paweł Weichbroth
    2022 Pełny tekst Procedia Computer Science

    This study compares the results of two completely different models: statistical one (ARIMA) and deep learning one (LSTM) based on a chosen set of NASDAQ data. Both models are used to predict daily or monthly average prices of chosen companies listed on the NASDAQ stock exchange. Research shows which model performs better in terms of the chosen input data, parameters and number of features. The chosen models were compared using the relative metric mean square error (MSE) and mean absolute percentage error (MAPE). Selected metrics are typically used in regression problems. The performed analysis shows which model achieves better results by comparing the chosen metrics in different models. It is concluded that the ARIMA model performs better than the LSTM model in terms of using just one feature – historical price values – and predicting more than one time period, using the p, q parameters in the range from 0 to 2, Adam optimizer, tanh activation function, and 2xLSTM layer architecture. The longer the data window period, the better ARIMA performs, and the worse LSTM performs. The comparison of the models was made by comparing the values of the MAPE error. When predicting 30 days, ARIMA is about 3.4 times better than LSTM. When predicting an averaged 3 months, ARIMA is about 1.8 times better than LSTM. When predicting an averaged 9 months, ARIMA is about 2.1 times better than LSTM.

  • Artificial neural network based fatigue life assessment of friction stir welding AA2024-T351 aluminum alloy and multi-objective optimization of welding parameters
    • Reza Masoudi Nejad
    • Nima Sina
    • Danial Ghahremani Moghadam
    • Ricardo Branco
    • Wojciech Macek
    • Filippo Berto
    2022 Pełny tekst INTERNATIONAL JOURNAL OF FATIGUE

    In this paper, the fracture behavior and fatigue crack growth rate of the 2024-T351 aluminum alloy has been investigated. At first, the 2024-T351 aluminum alloys have been welded using friction stir welding procedure and the fracture toughness and fatigue crack growth rate of the CT specimens have been studied experimentally based on ASTM standards. After that, in order to predict fatigue crack growth rate and fracture toughness, artificial neural network is used. To obtain the best neuron number in the hidden layer of the artificial neural network, different neuron numbers are tested and the best network based on the performance is selected. Then the fitting method is applied and the fitted surfaces that illustrate the behavior of welding are shown and the results of artificial neural network and fitting method are compared. Also, multi-objective optimization algorithm is used to obtain the best welding parameters and finally sensitivity analysis is applied to measure the effect of rotational and traverse speeds on the fracture toughness and fatigue crack growth rate.

  • Asocjacje – jak gdyby, tak jakby…
    • Krzysztof Wróblewski
    2022

    Krzysztof Wróblewski prezentuje „In Touch / Anonymous”. (Twarz – jako maska, dłoń – jako dotyk i ślad) – dwa obrazy (olej na płótnie, wymiary: 146x228 cm) wraz z komentarzem: „W kuratorskim tekście do wystawy Asocjacje – jak gdyby, tak jakby zainteresował mnie cytat z teorii umysłu: jesteśmy świadomi umysłów innych ludzi i to ma wpływ na nasze poczynania i procesy umysłowe. Sztuka jako jedno z narzędzi komunikacji jest wysyłaniem i odczytywaniem sygnałów, opartym głównie na intuicji i sieci skojarzeń (asocjacji). Idąc tym tropem i odpowiadając na temat wystawy, połączyłem we wspólny sygnał dwa obrazy: „In Touch” oraz „Anonymous”. Obraz „In touch” to chęć zbudowania metafory tego, czego wszyscy doświadczali na początku pierwszego zamknięcia w marcu 2020 roku podczas wybuch pandemii Covid-19. Popularny w języku angielskim zwrot wyrażający bycie w kontakcie zawierał w sobie problematyczny wtedy rzeczownik „dotyk”. Kontakt to dotyk – fizyczny ale też mentalny. (…) Impulsem do namalowania niewielkiego obrazu „Anonymous” były akcje przeprowadzone przez internetowe grupy hakerów, których celem było wspomagania Ukrainy w jej walce przeciwko militarnej agresji Rosji. Anonimowi aktywiści ukrywają twarze pod maską Guya Fawkesa, która rozpowszechniła się po 2006 roku wśród różnych grup protestacyjnych występujących przeciwko rządom, bankom i instytucjom finansowym. Maska chroni nie tylko tożsamość buntowników, ale symbolizuje też ich zjednoczenie we wspólnej sprawie. Aktywiści Anonymous nie są anarchistami lecz rebeliantami, którzy sprzeciwiają się ograniczaniu wolności oraz agresji. Świat tworzą i zmieniają dłonie miliardów ludzi, których twarze przybiera ją wielorakie maski. Skala ich dokonań ma różne rozmiary – od prawie niewidocznych po gigantyczne. Jak powiedział Juhani Pallasmaa: „Dłonie stanowią część indywi dualnej osobowości i charakteru, ale wykonują również swoje niezależne działania, i jako wyposażone we własny język, mają kluczowe znaczenie dla ludzkiej komunikacji”. Łącząc dwa obrazy w jeden przekaz chcę powiedzieć, że potrzebujemy symboli i znaków, które jednoczą często bezimienne działania i losy. Wierzę w myślące oblicze dłoni”. Krzysztof Wróblewski

  • Aspekty formalno-prawne współczesnej gospodarki energetycznej
    • Waldemar Kamrat
    2022

    Przedstawiono najbardziej istotne akty prawne , dyrektywy,zarządzenia rozporządzenia regulujące procesy gospodarowania energią

  • Assessing Roadside Hybrid Energy Absorbers Using the Example of SafeEnd
    • Marcin Budzyński
    • Kazimierz Jamroz
    • Łukasz Jeliński
    • Dawid Bruski
    • Łukasz Pachocki
    • Grzegorz Baginski
    2022 Pełny tekst Materials

    A combination of crash cushion and end-terminal, hybrid energy absorbing devices have been in use worldwide for a few years already. They include SafeEnd, a system Poland has recently introduced. Some road authorities have raised concerns as regards the operating conditions of the devices and how they work together with safety barriers. The objective of this research is to clarify the concerns and answer the following questions: (1) Can SafeEnd devices be used as hybrid devices and combine the roles of end-terminal and crash cushion placed before an obstacle? (2) What should be the rules for installing crash cushions at diverging roads and at the start of an off-ramp? The article presents characteristics of SafeEnd devices, defines the doubts raised by road safety auditors, discusses the results of field and numerical tests of the devices and explains the design principles for interchange ramps where crash cushions are required. The study results have helped to answer the research questions: SafeEnd devices fulfil the role of end-terminal and crash cushion, it is possible to make them more visible and principles have been defined for how the devices should be used at road interchanges. Further research should help to define general principles of deploying road restraint systems such as crashworthy terminals, crash cushions or hybrid devices.

  • Assessment of Adjustment of GNSS Railway Measurements with Parameter-Binding Conditions in a Stationary Scenario
    • Pawel S. Dabrowski
    • Cezary Specht
    • Mariusz Specht
    • Paweł Burdziakowski
    • Oktawia Lewicka
    2022 Pełny tekst Applied Sciences-Basel

    The study aims to assess the applicability of the ordinary least squares method, robust estimation, and conditions-binded adjustment in processing the six synchronous coordinate pairs of global navigation satellite system (GNSS) receivers. The research is part of the research project InnoSatTrack, focused on the enhancement of the determination of geometrical parameters of railway tracks using GNSS, inertial, and other sensors. A fixed frame of installation of six receivers is used in the data processing. Due to the limited availability of railway routes for measurements, the stationary campaign was conducted to gather data for the adjustment procedures tests. Six GNSS receivers in the frame-restricted configuration were set up using the tachymetric method for recording 96,729 synchronous static observations. Post-processed coordinates of the receivers were adjusted according to the geometrical conditions of the survey frame. Analysis showed higher applicability of the conditions-binded method than other estimation methods by obtaining superior results in both the precision and the maintenance of the design conditions factors than in the OLS and robust estimators.

  • Assessment of E-government inclusion policies toward seniors: A framework and case study
    • Magdalena Ciesielska
    • Nina Rizun
    • Jakub Chabik
    2022 Pełny tekst TELECOMMUNICATIONS POLICY

    Digital exclusion of seniors covers both social and technical drivers that affect the magnitude of this phenomenon. It arises from the fear of technology, reduced manual and mental abilities, socio-economic status, and also the mismatch between the technological environment and the needs of the elderly. The consideration of the needs of seniors are mainly implemented through social policies while the provision of government services is achieved through digitization policies and procedures. Our research is addressing two objectives. The first objective is to identify the main determinants affecting the adoption of e-government and its use by seniors. The second objective is to build a research framework for assessing e-government policy for the digital inclusion of the seniors from both social and technical perspectives. This research framework is then validated based on a case study of Poland. Presented framework proves to be a useful tool to evaluate and depict the areas of improvement for a comprehensive e-government policy toward seniors' inclusion.

  • Assessment of Environmental Loads in the Life Cycle of a Retail and Service Building
    • Daniel Tomporowski
    • Robert Kasner
    • Wojciech Franus
    • Krzysztof Doerffer
    2022 Pełny tekst ENERGIES

    In order to achieve the European Union’s climate and energy goals, investments are required, mainly in the areas of energy efficiency, renewable energy sources and infrastructure. Buildings are responsible for almost half of total energy consumption, and nearly 80% of them are energy and ecologically inefficient. The policy of European countries is increasingly more focused on facilities with the highest potential in the areas of energy and matter saving and the possibly circular economy. The aim of the work was to assess the environmental loads occurring in the life cycle of an existing retail and service building. The analysis was performed using the Life Cycle Assessment (LCA) method. By using the IMPACT 2002+ model, it has become possible to assess the impact of the life cycle of the studied facility on human health, environmental quality, climate change and raw material resources. The highest level of negative consequences in the above-mentioned areas was recorded for the life cycle with the disposal in the form of landfill storage. The operational stage was the stage in the life cycle that caused the most harmful impacts on the environment. Therefore, it is necessary to optimize the ecological and energy consumption of resources, for example, by selecting the size and cubature of the facility for its function, maintaining good technical condition, introducing improvements in the usage processes or implementing solutions aimed at reducing media consumption. As a result of the conducted analyses, it can be noticed that in the future, the reduction in energy consumption in the operation of buildings will be of fundamental importance.

  • Assessment of River Water Quality and Pollution Status Using Physicochemical and Biometrics, Awetu River, Ethiopia
    • Dessalegn Geleta Ebsa
    • Worku Firomsa Kabeta
    2022 Pełny tekst GEOFLUIDS

    The surface water is contaminated by a variety of synthetic organic and inorganic compounds, chemicals, and nutrients; due to this reason, the quality of the water resources of Ethiopia is declining at an alarming rate, resulting in severe environmental degradation. The main objective of the study was to recognize the pollution status river for the study area by physicochemical parameters and the extent of microbial environmental matrices. The experiment was conducted using a complete randomized model with three composite replicates in each site, and water samples were collected from six different sampling sites using the American Public Health Association (APHA) technique. Water quality parameters were analyzed by the standard method of examination, whereas same examination was determined on site (in situ) (pH, Temp, Conductivity, and Turbidity), whereas TSS, COD, BOD, nitrate, alkali, and orthophosphate were identified in the laboratory. The relationship between physicochemical and benthos assemblages as bio indicators of ecohydrological river water quality was investigated using Spearman’s median rank correlation. The output of the study reveals that there was a negatively significant difference in effect between the sample and all the sites of the river. Physicochemical results of the river indicate Temp (23.62), EC (101.42), nitrate (2.175), and orthophosphates (0.081) were below the standard guidelines; however, turbidity (8.41), BOD (784.5), and alkali (396.5) were above the standard. Same of the water quality values for this study were ranges within the standard, DO (5.11), and pH (7.66). The benthos assemblage communities of the ecohydrological area were more influenced by the influents,and the macroinvertebrate index of all sample sites indicates the Shannon and Simpson diversity indices; result shows that the river was lightly polluted.

  • Assessment of the application of CEM III with exposed aggregate as an alternative to CEM I for road pavements
    • Marzena Kurpińska
    • Aldona Wcisło
    2022 Pełny tekst Archives of Civil Engineering

    The article presents a results of study on the impact of replacing CEM I SR3/NA by CEMIII/A LH/HSR/NAon the mechanical properties and durability of pavement concrete with exposed aggregate. Was used granite aggregate and washed sand. Water/cement () ratio in the tested concretes constituted 0.35 and 0.4 and part of the cement was replaced with a 5% addition of natural pozzolana – zeolite. Compressive strength tests were performed after 3, 7, 28 and 56 days, tests of tensile strength test by splitting method and flexural strength two-point loading tests. The characteristics of the air pores and the rate of water absorption by concrete surface of the samples cut out from the slabs with exposed aggregate were presented. The resistance of the surface to exfoliation after 56 cycles of freezing-thawing in NaCl solution was tested. Based on the results obtained, it was found that when designing the composition of the concrete intended for the upper layer of the pavement, it is necessary to ensure high tensile strength, appropriate in the XF4 environment and with the decrease in the  Ÿ 0•4, a reduction in capillary porosity of the cement paste is obtained, and the same the durability of concrete is increased due to the improved strength parameters in the contact zone between coarse aggregate grains and cement paste. The research also showed a significant influence of proper cure on the mechanical properties and durability of pavement concrete.