2022 - Repozytorium publikacji - Politechnika Gdańska

Pokaż publikacje z roku

Publikacje z roku 2022

Pokaż wszystkie

Combined cold supply system for ship application based on low GWP refrigerants - Thermo-economic and ecological analyses
- Jan Wajs
- Michał Mrózek
- Elzbieta Fornalik-Wajs
2022 Pełny tekst ENERGY CONVERSION AND MANAGEMENT
The withdrawal of popular high-GWP refrigerants will significantly affect maritime industry. Refrigeration and air conditioning systems currently used on ships are not ready to fulfil future limitations. Therefore, there is a need for system, which will operate with low-GWP refrigerants and at the same time will be efficient and reliable in difficult environmental conditions. This paper explains the concept of a cold supply system, in which refrigeration/freezing plant rejects heat not to a seawater but to a chilled water, produced by the air conditioning unit. Configuration of single stage compression with internal heat exchanger and HFO refrigerant was used in the air conditioning system, while in the refrigeration/freezing plant, two-stage compression trans-critical booster with R744 as refrigerant. Comparative thermodynamic analyses of presented concept with other configurations of thermodynamic cycles and refrigerants were performed. They were carried out in wide range of seawater temperature values and incorporated efficiency characteristics of compressors produced by a well-known manufacturers. Results confirmed ability of described system to improve energy efficiency in comparison with separated and currently used on ships cold supply systems, especially in hot climate. Economic and ecological analyses of proposed concept exhibited an additional benefit - positive environmental impact.
Combined numerical and experimental approach to determine numerical model of abdominal scaffold
- Agnieszka Tomaszewska
- Daniil Reznikov
2022 Pełny tekst COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING
A proper junction of the prosthesis and the abdominal wall is important in successful hernia repair. The number of tacks should be balanced to assure appropriate mesh fixation and not to induce post-operative pain. Numerical simulations help to find this balance. The study is aimed at creating a proper numerical model of a knitted surgical mesh subjected to boundary conditions and load occurring in the abdominal cavity. Continuous, anisotropic constitutive relation is considered to reflect the mesh behaviour. Different sets of material law parameters are determined on the basis of different bi-axial tests setups. Force- and displacement-controlled tests with different ratios are considered. Consequently, some numerical model variants are obtained featuring various reaction distributions in the scaffold fixation points. The proper variant is selected based on comparison of the position of maximal reaction force in the numerical model and in the reference physical model of operated hernia. Force-driven tests have shown anisotropic mesh behaviour, while equibiaxial displacement-driven test has demonstrated reduced anisotropic response. Within seven scenarios of constitutive parameters identification (based on single or combined experimental data), the equibiaxial force-controlled test appeared to produce the most relevant model to follow the prosthesis behaviour under pressure. The position of maximal reaction force in such model is similar to obtained in the physical hernia model. The equibiaxial force-driven test provides most suitable data for Gasser-Ogden-Holzapfel constitutive model identification of a considered surgical mesh to be used to model the mesh under pressure
Combined partial denitrification/anammox process for nitrogen removal in wastewater treatment
- Hussein Al-Hazmi
- Dominika Derwis
- Joanna Majtacz
- Aleksandra Ziembińska-Buczyńska
- Jun Zhai
- Jacek Mąkinia
2022 Journal of Environmental Chemical Engineering
Recently, the combined partial denitrification and anammox (PD/anammox) has received special attention as a viable alternative for N removal using organic matter present in municipal wastewater. In comparison with conventional nitrification-denitrification, PD/anammox provides enormous opportunities to achieve sustainable wastewater treatment due to the lack of dissolved oxygen (DO) demand, a smaller amount of organic carbon (C) and less excess sludge production and GHG emissions. The PD/anammox process can be widely carried out in different technical systems, including single- or two-stage systems for side-stream and mainstream wastewater. This review focuses on the latest improvements related to the PD/anammox system and discusses the production/consumption pathways of NO2- as a critical intermediate. The C/N ratio plays a key role in the PD/anammox process; therefore, the concentration of the dosed organic C is important due to its negative influence on the activity of anammox resulting from the overgrowth of denitrifying bacteria in the systems. Understanding microorganism competition in a one-stage PD/anammox is typically the most important key to optimal efficiency of N removal from mainstream wastewater. Therefore, in this review, a comprehensive description of microbial metabolism i.e., autotrophic anammox, denitrifying heterotrophs/autotrophs, DNRA heterotrophs, and the contiguity competition between them in single-stage PD/anammox systems are inclusively explained. The challenge and limitations are described to recognize inhibition mechanisms and performance inhibitors. The combination of PD/anammox with other processes and the development of a self-supporting bacterial system should be the main lines of future research and efficiency development towards further enhancing total nitrogen removal efficiency (TNRE).
COMMON FIRE CAUSES IN INDUSTRIAL SITES
- Mehmet Gökçü
- Mariusz Jaczewski
2022
Chapter presents common causes of fires in industrial places
Communication as a Factor Limiting University-Business Cooperation
- Sylwia Sieracka
- Marek Wirkus
2022 GATR Global Journal of Business and Social Science Review
Objective - Despite the broad extent of the scientific activity dealing with university-business cooperation, Poland has yet to develop a satisfactory cooperation strategy that takes business needs into account. This issue is still relevant due to the need for continuous improvement and resulting benefits aimed at improving enterprise competitiveness. Methodology/Technique - Authors of this article attempt to select an overriding determinant that has an impact on maintaining the balance of cooperation between businesses and universities, constituting the basis for further research on the creation of a cooperation strategy. Finding - Based on the conducted pilot studies, the authors propose the implementation of marketing orientation towards business-university relations, influencing the improvement of communication and selective drawing of ideas from the experiences of other countries. Novelty - The proposed solutions aim to initiate further activities to build global cooperation networks using artificial intelligence tools, i.e. a broker platform. Keywords: Communication, business, university, cooperation, marketing orientation
Compact and Integrated High-Power Pulse Generation and Forming System
- Mikołaj Nowak
- Kazimierz Jakubiuk
- Daniel Kowalak
- Marek Pikoń
- Józef Czucha
- Piotr Jankowski
2022 Pełny tekst ENERGIES
This paper presents comprehensive analytical, numerical and experimental research of the compact and integrated high-power pulse generation and forming system based on the flux compression generator and the electro-explosive forming fuse. The paper includes the analysis of the presented solution, starting from the individual components studies, i.e., the separate flux compression generator tests in field conditions and the forming fuse laboratory test, through the formulation of the extended quasi-empirical components models aimed at enabling their optimal parameters determination at the early design stage and ending with the description of the integrated system studies in field conditions. Based on detailed research, it was possible to achieve very high parameters of the generated pulses, i.e., overvoltages of up to 340 kV with the available source power reaching 25 GW. A very high convergence of the simulation and the results of experimental research has been obtained. The parameters of the presented system have been compared with other literature solutions and the selected topology of the high power pulse generation and forming system has been distinguished against other available ones, e.g., based on Marx generators and forming lines.
Compact Electromagnetic Lens Antennas Using Cascaded Metasurfaces for Gain Enhancement and Beam Steering Applications
- Rao Aziz
- Amit Singh
- Jun-Sung Park
- Seong-Ook Park
- Sławomir Kozieł
2022 INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING
Electromagnetic (EM) lens antenna designs using cascaded metasurfaces for gain enhancement and beam steering applications are proposed. Two different lens aperture designs are proposed and populated with aperiodic unit cells of size 0.2λo × 0.2λo. In lens Design 1, the unit cells of different phases are distributed in concentric circular zones, whereas in lens Design 2, the unit cells of different phases are distributed in vertical linear zones on the aperture of the EM lens. Both lenses are composed of two cascaded metasurfaces with an air gap of 0.047λo (where λo = 51.7 mm at 5.8 GHz). For gain enhancement, the metasurfaces are positioned at an optimum focal distance, f = 0.61λo above source patch antenna (f/D = 0.3). Beam steering is accomplished by phase transformation of the source antenna, which can be realized by mechanically sliding the passive metasurfaces in one direction (i.e., ±x-direction) above the source antenna. The prototype of the two proposed lenses are fabricated and tested. The measured peak boresight gain obtained from Design 1 and 2 are 14.98 dBi and 15.12 dBi, respectively. The experimental results show -25o to +25o and -27o to +27o beam steering range for Design 1 and 2, respectively, with a little gain degradation at other angles.
Compact High Efficiency and Zero-Emission Gas-Fired Power Plant with Oxy-Combustion and Carbon Capture
- Paweł Ziółkowski
- Stanisław Głuch
- Piotr Józef Ziółkowski
- Janusz Badur
2022 Pełny tekst ENERGIES
Reduction of greenhouse gases emissions is a key challenge for the power generation industry, requiring the implementation of new designs and methods of electricity generation. This article presents a design solution for a novel thermodynamic cycle with two new devices—namely, a wet combustion chamber and a spray-ejector condenser. In the proposed cycle, high temperature occurs in the combustion chamber because of fuel combustion by pure oxygen. As a consequence of the chemical reaction and open water cooling, a mixture of H2O and CO2 is produced. The resulting working medium expands in one turbine that combines the advantages of gas turbines (high turbine inlet temperatures) and steam turbines (full expansion to vacuum). Moreover, the main purpose of the spray-ejector condenser is the simultaneous condensation of water vapour and compression of CO2 from condensing pressure to about 1 bar. The efficiency of the proposed cycle has been estimated at 37.78%. COM-GAS software has been used for computational flow mechanics simulations. The calculation considers the drop in efficiency due to air separation unit, carbon capture, and spray-ejector condenser processes. The advantage of the proposed cycle is its compactness that can be achieved by replacing the largest equipment in the steam unit. The authors make reference to a steam generator, a conventional steam condenser, and the steam-gas turbine. Instead of classical heat exchanger equipment, the authors propose non-standard devices, such as a wet combustion chamber and spray-ejector condenser.
Compact, Order Extensible and Wide-Stopband Bandpass Filter Based on SIW Cavity with Rectangular Ring Slot
- Rusan Kumar Barik
- Sławomir Kozieł
2022 IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-EXPRESS BRIEFS
This article introduces novel architectures of bandpass filters (BPFs) using a substrate integrated waveguide (SIW) cavity with a rectangular ring slot (RRS) for compact size, extensible order, and broad stopband responses. Two bandpass filters, which demonstrate a second-and a fourth-order Chebyshev response, respectively, are realized by employing identical cavities with RRS, without increasing the physical size of the circuit. A rectangular ring slot is etched along the perimeter and a metallic via is allocated towards the bottom edge of the cavity to realize the resonances. The resonant frequencies of different modes are controlled by introducing one or three slots, which enable the realization of the second and fourth-order BPFs with wide stopbands, respectively. The working principles of the filters are illustrated by applying the eigen-mode analysis, field distribution, and the coupling matrix. Finally, a second-order BPF centered at 0.87 GHz, and a fourth-order BPF centered at 0.92 GHz are synthesized, fabricated, and experimentally validated. As compared to the earlier works, the proposed fourth-order BPF offers competitive performance with a low insertion-loss of 0.7 dB, compact size of 0.036λ2, and a wide passband of 22.1%. Additionally, the second- and the fourth-order BPFs achieve wide upper stopband responses of 3.86f0 at a level greater than 20dB and 3.98f0 at a level greater than 30dB, respectively.
Comparable analysis of PID controller settings in order to ensure reliable operation of active foil bearings
- Łukasz Witanowski
- Łukasz Breńkacz
- Natalia Szewczuk-Krypa
- Marta Drosińska-Komor
- Bartosz Puchalski
2022 Pełny tekst Eksploatacja i Niezawodność - Maintenance and Reliability
In comparison to the traditional solutions, active bearings offer great operating flexibility, ensure better operating conditions over a wider range of rotational speeds and are safe to use. In order to ensure optimum bearing performance a bearing control system is used that adapts different geometries during device operation. The selection of optimal controller parameters requires the use of modern optimization methods that make it possible to quickly achieve the assumed parameters. This article presents the method that has been employed to select the parameters of a proportional integral derivative (PID) controller, in which both stochastic algorithms and hybrid methods have been compared. The results show that all of the used algorithms were able to reach the global optimum but only the hybrid algorithm was repeatable in all runs within a low value of the standard deviation. The best solution will be proposed in the future to control an active foil bearing. Analysing of this paper would help to prevent failures of active foil bearing used in the designed rotating machine.
Comparative Analysis of Developed Rainfall Intensity–Duration–Frequency Curves for Erbil with Other Iraqi Urban Areas
- Dalshad Ahmed Kareem
- Aumed Rahman M Amen
- Andam Mustafa
- Mehmet Ishak Yüce
- Michał Szydłowski
2022 Pełny tekst Water
Rainfall Intensity–Duration–Frequency (IDF) relationships are widely used in water infrastructure design and construction. IDF curves represent the relationship between rainfall intensity, duration, and frequency, and are obtained by analyzing observed data. These relationships are critical for the safe design of flood protection structures, storm sewers, culverts, bridges, etc. In this study, the IDF curves and empirical IDF formulas for the city of Erbil were developed for the first time by employing the annual maximum rainfall data for a period of 39 years (1980–2018), which is the only available recorded data. Statistical techniques such as Gumbel and Log-Pearson Type III (LPT III) were utilized to determine the IDF curves and empirical equations from daily rainfall data for several standard durations and return periods. The correlation between the rainfall intensities obtained from IDF curves and the empirical formula presented a reliable match, with a coefficient of determination of (R2 = 1). The results were compared to previously developed IDF curves and empirical formulas in Iraqi cities to show their reliability. Moreover, the results can be an initial step for authorities to establish required guidelines in the studied area, and in the design process of the storm water infrastructure of urban basins in the future.
Comparative analysis of mRNA transcripts of HT-29 cell line expressed in identical quantities for pathogenic E. coli strains UM146 and UM147 with control Escherichia coli Nissle 1917
- Roman Kotłowski
2022 Pełny tekst Journal of Genomics
Aim of study was comparative analysis of mRNA transcripts of HT-29 cell line, expressed in identical quantities for the combination of pathogenic and non-pathogenic Escherichia coli strains. HT-29 confluent monolayers infection with two pathogenic E. coli strains UM146 and UM147 resulted in two sets of mRNA transcripts that were identical with RNA transcripts obtained for non-pathogenic one strain E. coli Nissle 1917. In this study genome-wide experiments were conducted using expression microarray-system. Only one common mRNA transcript coding for CCDC65 gene was equally expressed by HT-29 cells after incubation challenge with three different E. coli strains used. This gene and its bacterial analogue are important in the ciliary or flagellar motility, respectively. Altogether, 78 and 81 HT-29 mRNA transcripts for E. coli UM146 and E. coli UM147 had identical RNA quantity in comparison to the response obtained for non-pathogenic E. coli Nissle 1917 interactions with HT-29 monolayers. Specific analysis using REACTOME and agriGO terms enrichment data-mining tools as well as word-cloud analysis allowed for identification the most important processes characteristic during HT-29 cell line infections for each pathogenic E. coli strain used. The importance of results may contribute to recognition of those processes during bacterial infections that are identical with processes arising from human interaction with non-pathogenic strains that belong to the same bacterial species.
Comparative Analysis of Reactive Power Compensation Devices in a Real Electric Substation
- Hanan Tariq
- Stanislaw Czapp
- Sarmad Tariq
- Khalid Mehmood Cheema
- Aqarib Hussain
- Ahmad H. Milyani
- Sultan Alghamdi
- Z. M. Salem Elbarbary
2022 Pełny tekst ENERGIES
A constant worldwide growing load stress over a power system compelled the practice of a reactive power injection to ensure an efficient power network. For this purpose, multiple technologies exist in the knowledge market out of which this paper emphasizes the usage of the flexible alternating current transmission system (FACTS) and presents a comparative study of the static var compensator (SVC) with the static synchronous compensator (STATCOM), inducted in a real electric substation. The aim is to improve the power factor (PF) and power quality and to encounter reliably extreme conditions. A 220 kV electric substation was opted for the analysis, and both the static and dynamic conditions were observed with the help of a power system analysis tool termed PowerFactory-DIgSILENT. Multiple aspects were investigated via software simulations to assess the performance of the aforementioned FACTS devices, such as the voltage profile evaluation via the load flow analysis method (LFA), the harmonic response via the power quality and harmonic analysis tool, and the short-circuit response via the RMS simulation tool. The outcomes were verified and compared with permissible values included in the universal standards, such as IEC and IEEE. The superiority of the STATCOM over the SVC was proven in light of the simulative results.
Comparative analysis of the flow control over a circular cylinder with detached flexible and rigid splitter plates
- Faezeh Eydi
- Afsaneh Mojra
- Rezvan Abdi
2022 Pełny tekst PHYSICS OF FLUIDS
A comparative study is performed on a circular cylinder with both flexible and rigid splitter plates (SPs). This study has the novelty of using single and dual detached SPs located downstream of the cylinder. The dimensionless gap distance between the first splitter plate and the cylinder as well as the distance between the SPs are varied. The strain of flexible SPs can be used for energy harvesting from the flow. Therefore, a parametric study is performed to find the optimal design for placing piezoelectric polymers. The two-dimensional fluid–structure-interaction analysis is performed based on the arbitrary Lagrangian–Eulerian scheme using COMSOL Multiphysics. Flow characteristics quantities, tip amplitude, and strain are evaluated at different arrangements of the SPs. The results reveal that wake control enhances effectively by doubling the number of SPs. Strain assessments indicate that the strain of dual SPs increases by more than 100% compared to the single plate case. In addition, the amplitude of the dual SPs increases by a remarkable ratio of 18.29 compared to the single plate. In the case of rigid and flexible SPs at a certain arrangement, dramatic reductions of 97.8% and 76.35% in the Strouhal number are obtained compared to a bare cylinder. In addition, 18% drag reduction compared to the bare cylinder is recorded for the rigid SPs. The presented passive method can be used as an attractive approach in flow control as well as energy harvesting from ocean waves and sea currents.
Comparative Assessment of Bacteriophage and Antibiotic Activity against Multidrug-Resistant Staphylococcus aureus Biofilms
- Natalia Kaźmierczak
- Bartłomiej Grygorcewicz
- Marta Roszak
- Beata Bochentyn
- Lidia Piechowicz
2022 Pełny tekst INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
Problems connected with biofilm-related infections and antibiotic resistance necessitate the investigation and development of novel treatment strategies. Given their unique characteristics, one of the most promising alternatives to conventional antibiotics are bacteriophages. In the in vitro and in vivo larva model study, we demonstrate that phages vB_SauM-A, vB_SauM-C, and vB_SauM-D are effective antibiofilm agents. The exposure of biofilm to phages vB_SauM-A and vB_SauM-D led to 2–3 log reductions in the colony-forming unit number in most of the multidrug-resistant S. aureus strains. It was found that phage application reduced the formed biofilms independently of the used titer. Moreover, the study demonstrated that bacteriophages are more efficient in biofilm biomass removal and reduction in staphylococci count when compared to the antibiotics used. The scanning electron microscopy analysis results are in line with colony forming unit (CFU) counting but not entirely consistent with crystal violet (CV) staining. Additionally, phages vB_SauM-A, vB_SauM-C, and vB_SauM-D can significantly increase the survival rate and extend the survival time of Galleria mellonella larvae.
Comparative review of piezoelectric biomaterials approach for bone tissue engineering
- Ali Samadi
- Mohammad Amin Salati
- Amin Safari
- Maryam Jouyandeh
- Mahmood Barani
- Narendra Pal Singh Chauhan
- Elias Ghaleh Golab
- Payam Zarrintaj
- Saptarshi Kar
- Farzad Seidi
- Aleksander Hejna
- Mohammad Saeb
2022 JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION
Bone as a minerals’ reservoir and rigid tissue of the body generating red and white blood cells supports various organs. Although the self-regeneration property of bone, it cannot regenerate spontaneously in severe damages and still remains as a challenging issue. Tissue engineering offers several techniques for regenerating damaged bones, where various biomaterials are examined to fabricate scaffolds for bone repair. Piezoelectric characteristic plays a crucial role in repairing and regenerating damaged bone by mimicking the bone niche behavior. Piezoelectric biomaterials show significant potential for bone tissue engineering. Herein we try to have a comparative review on piezoelectric and non-piezoelectric biomaterials used in bone tissue engineering, classified them, and discussed their effects on implanted cells and manufacturing techniques. Especially, Polyvinylidene fluoride (PVDF) and its composites are the most practically used piezoelectric biomaterials for bone regeneration. PVDF and its composites have been summarized and discussed to repair damaged bone tissues.
Comparative study of high‑pressure fluid flow in densely packed granules using a 3D CFD model in a continuous medium and a simplified 2D DEM‑CFD approach. Granular Matter
- Rezvan Abdi
- Marek Krzaczek
- Andrzej Tejchman-Konarzewski
2022 Pełny tekst GRANULAR MATTER
Izotermiczny ściśliwy jednofazowy przepływ cieczy przez niejednorodną masę ziarnistą składającą się z gęsto upakowanych zachodzących na siebie kul imitujących skałę pod wysokim ciśnieniem zbadano numerycznie przy użyciu dwóch różnych podejść. Pierwsze podejście zwane pełnym modelem 3D CFD stosowało metodę skończonych objętości (FVM) do rozwiązania uśrednionego równania Naviera-Stokesa zakładając model naprężeń Reynoldsa (BSL) w osrodku ciągłym pomiędzy granulatami. Model został zweryfikowany na podstawie wyników doświadczalnych i liczbowych z literatury. Drugim podejściem był uproszczone sprzężone podejście DEM-CFD oparte na tzw. modelu sieci przepływu. Głównym celem pracy było opracowanie procedury walidacji uproszczonych sprzężonych modeli DEM-CFD ze względu na brak danych doswiadczalnych dla charakterystyk przepływu płynu w gęsto upakowanych granulatach w warunkach ekstremalnie wysokiego ciśnienia. Najpierw przeprowadzono serię symulacji numerycznych dla osrodka płynu z pełnym modelem 3D CFD. Wyniki tych symulacji zostały następnie wykorzystane do walidacji wyników numerycznych 2D uproszczonego sprzężonego modelu DEM-CFD w odniesieniu do prędkości, ciśnień, gęstości i szybkości przepływu. W obu podejściach uzyskano prawie takie same rozkłady ciśnienia i gęstości oraz natężenia przepływu masowego. Prędkość płynu była jednak inna ze względu na różne objętości płynu w obu ośrodkach. Wyniki symulacji numerycznych stanowią wiarygodny punkt odniesienia dla walidacji innych połączonych modeli 2D/3D DEM-CFD, które wykorzystują modele sieciowe.
Comparison of image pre-processing methods in liver segmentation task
- Kamil Kaczor
- Paweł Nadachowski
- Maksymilian Operlejn
- Artur Piastowski
- Marta Zielonka
- Jan Cychnerski
- Alicja Kwaśniewska
2022
Automatic liver segmentation of Computed Tomography (CT) images is becoming increasingly important. Although there are many publications in this field there is little explanation why certain pre-processing methods were utilised. This paper presents a comparison of the commonly used approach of Hounsfield Units (HU) windowing, histogram equalisation, and a combination of these methods to try to ascertain what are the differences between them and how big the differences are. All experiments were conducted on the LiTS dataset. To achieve comparable and reliable results only one architecture of neural network is used which is U-Net with ResNet34 blocks
Comparison of the characteristics of journal bearings determined according to ISO 7902:2020 and obtained by other methods
- Jan Smykla
- Michel Fillon
- Artur Olszewski
- Tomasz Żochowski
- Lidia Gałda
2022 PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART J-JOURNAL OF ENGINEERING TRIBOLOGY
The article presents selected characteristics of journal bearings calculated with the use of various methods and compared to the results obtained with application of the basic bearing characteristics calculation procedure, as described in the ISO 7902:2020 standard. Additionally, the presented calculation results were compared with the parameters measured during experimental tests of the sliding bearings, working under loads and at sliding velocity, and maintaining other operating conditions, as assumed in theoretical research. The regula falsi iteration method was successfully implemented. The research results have con fi rmed the usefulness of various calculation methods since the values of selected characteristics of the journal bearing obtained were comparable.
Comparison of the Efficiency of Deammonification under Different DO Concentrations in a Laboratory-Scale Sequencing Batch Reactor
- Hussein Al-Hazmi
- Z. Yin
- Dominika Grubba
- Joanna Majtacz
- Jacek Mąkinia
2022 Pełny tekst Water
The efficiency of deammonification depends on the cooperation of ammonium oxidizing bacteria and archaea (AOB/AOA), anaerobic ammonium oxidizing bacteria (AnAOB) and the effective suppression of nitrite oxidizing bacteria (NOB) that compete with AnAOB for nitrite (NO2 -N). One of the effective NOB suppression strategies is intermittent aeration. However, it is important to have a good understanding of the optimum dissolved oxygen (DO) value in the aeration period and optimize the non-aeration time used during the reaction phase. This study comprised the investigation of the effect of different DO set points (0.4, 0.7, 1.0 and 1.5 mg O2/L) under the same aeration length off/on (12/3 min). Moreover, three different intermittent aeration modes (9/3, 6/3, 3/3) under the same DO set point (0.7 mg O2/L) were more investigated. The experiment was conducted for 6 months (180 days) in a laboratory-scale sequencing batch reactor (SBR) with a working volume of 10 L. The results indicated that a high N removal efficiency was achieved 74% at the DO set point = 0.7 mg O2/L during aeration strategy off/on (6/3 min) due to the low nitrate production rate (NPR) 0.9 mg N/g VSS/h and high ammonium utilization rate (AUR) 13 mg N/g VSS/h (NPR/AUR = 0.06). Mathematical modeling results confirmed that the feasible DO set point 0.7 and intermittent aeration mode off/on (6/3 min) were especially suitable for the optimal balance between the NOB suppression and keeping high activities of AOB and anammox in the system.