English Polski
Akademia Morska w Szczecinie

DSpace Home

DSpace/Manakin Repository

Browsing by Title:

  • Trojanowski, Piotr (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    The constant development of transport systems and the extensive activities related to the safety of its users necessitate the development of methods for assessing the impact of road infrastructure expansion/modernization on road safety. The objective of this paper is to elaborate the concept of such an assessment, which will form part of the author’s activities aimed at creating a methodology for a comprehensive analysis of the operational reliability of transport systems. The concept of assessing the impact of road infrastructure development on road safety presented in this paper refers to the GAMAB and Road Safety Impact Assessment methods from the subject literature. Our method is based on a comparative analysis of the condition of road infrastructure before and following its expansion/modernization, based on commonly available data, which constitutes the main advantage of the concept presented in this paper. Furthermore, the coefficients for occurrence of adverse road events were determined, and then conclusions drawn on this basis. The acquired results constitute an argument for the correctness of the presented concept.
  • Galliková, Jana; Grenčík, Juraj; Barta, Dalibor; Barlok, Matej (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    This study investigates FMECA analysis and its potential use in improving the reliability and maintenance of the thermal deburring machine in a manufacturing company located in Slovakia. In the beginning, an overview of the FMEA/FMECA methods and their utilization for increased reliability are discussed. As a practical solution, the deburring machine EXTRUDE HONE TEM P-350 was chosen. Functions of its systems and components, thermal deburring process, its characteristics and in practice application are described. Maintenance policy in the company and the current state of maintenance of the machine are also presented. In addition, the study includes failure analysis which evaluates the riskiest systems of the machine. One element, hydraulic unit, is a subject for the FMECA analysis which envisions the assessment of the current failure modes using risk priority number (RPN) and proposals of prevention and detection action reducing the level of RPN. The final section focuses on influencing and improving maintenance and summarizing the potential benefits of FMECA Analysis for company and machine operation.
  • Załoga, Elżbieta; Stępień, Grzegorz (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    Digitisation of transport is a tool for achieving the European Union’s political goals included in the Digital Single Market Strategy for Europe. For rail transport, digital innovation is required to increase its competitiveness. One of the tools of the digital transformation of railways is 5G networks, the fifth generation of wireless communication systems. The purpose of this article is to present the benefits of implementing 5G network for railway operators. Focus was placed on its innovative features, such as ultra-fast access to Internet services, very high connection reliability, and extremely low data transmission delays. Examples of new services for railway operators based on the capabilities of 5G networks were presented. This article describes the unique functions of the 5G network in which resources can be flexibly allocated depending on current traffic needs thanks to the network slicing function, e.g., for services of key importance to rail traffic and commercial services for other market segments. Roadmap proposals for transforming the current rail communication network infrastructure towards the target FRMCS system are presented. The analysis was based on source materials from Nokia Corporation, available literature, EU documents and regulations, as well as institutional studies of the railway sector.
  • Tepe, Resul; Kayiran, Burhan; Açik, Abdullah (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    One of the most important factors affecting international trade is exchange rate fluctuations. To date, studies that have analyzed the effect of exchange rates have shown that the effect can vary from sector to sector and from country to country. The fact that this relationship has not been extensively studied in the fisheries industry is the motivation for this study. In this regard, the aim of this study is to determine whether changes in the real exchange rates of countries affect their fisheries production levels. Accordingly, we used the causality test developed by Emirmahmutoglu and Kose (2011), which takes into account both cross-sectional dependencies and heterogeneity. The data set used in this study consisted of 27 annual observations from 38 countries from 1990–2016. The results revealed that changes in the real exchange rate affected fisheries production. This situation shows that changes in exchange rates may affect the international demand for fisheries and serve as a source of motivation for producers.
  • German-Galkin, Sergey (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    Analytical research methods to determine the power characteristics of generator sets with vector control in an asynchronous squirrel-cage machine were developed and used to calculate the energy characteristics of generator sets with the field-oriented control (FOC) and direct torque control (DTC). The analytical calculations showed that a generator set with direct torque control had slightly better energy characteristics. Confirmation of the analytical calculation results was carried out using simulation models developed in the MATLAB-Simulink package with an environment Simscape Power System.
  • Starczewska, Weronika; Uhl, Tadeus (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    In today’s production and service systems, the management process plays a primary role. Analysis of the management process allows the detection of weaknesses and strengths in analyzed systems. This paper analyses production line management processes. For one literature example, a queuing model of a selected production line was built, and its performance and reliability were analyzed. The modelling attempt undertaken here was designed to determine whether queuing theory is suitable for modelling production line processes. Confirmation of this thesis would be a novelty in this field.
  • Ziętek, Ryszard; Woźniak, Marcin (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    In this paper, a mini-crane control system using an exoskeleton based on programmable logic technology is presented. The first stage was to identify the parameters of the mini-crane and exoskeleton sub-assemblies. Then, individual crane and exoskeleton control subsystems were designed based on cascade regulation. The final stage was to connect these subsystems into the master-slave control system using the manipulator’s kinematics equations. Parallel processing was used to minimize delays in the control system. Analysis of the results showed that the difference between the set and measured crane position was small.
  • Pluskota, Przemysław (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    The development of any region is a complex phenomenon that depends on various factors, including a financial infrastructure that supports enterprises and other business entities. Issues related to the impact of financial institutions on economic development are often addressed in the academic literature. Some researchers claim that the development of financial institutions and instruments leads to the development of the entire country, indicating a close correlation between them. Others confirm this interdependence; however, they argue that it is non-linear and it depends on other factors, such as the country’s level of economic development, as well as how advanced its financial infrastructure is. Few studies have addressed the impact of regional financial institutions on regional development, and although macroscale studies have been implemented on the micro-level, they don’t necessarily reflect any interdependencies. Regional financial infrastructure plays an important role in regional development, and the Regional Development Funds (RDFs) that have recently appeared in some voivodeships confirm this interdependency. These institutions are likely to become integrators and stimulators of regional financial markets, and RDFs can become entities that manage capital that can be appreciated in many banks and exert a tangible effect on regional financial policies. At the same time, they will level any market flaws in terms of access to capital by micro-, small, and medium enterprises, as well as running growth-promoting policies tailored to the specific regional needs.
  • Magryta, Beata; Kołowrocki, Krzysztof (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    A method for reliability optimization, which is relevant for critical infrastructure activity governed by operational processes, is presented and applied to a port oil terminal. The optimal values for the reliability and resilience indicators related to the operation, are determined for this critical type of infrastructure. Simple suggestions regarding optimized infrastructural operation strategies are formulated and implemented towards reorganizing the port oil terminal processes in order to maximize its lifetime in defined reliability states.
  • Kotkowska, Diana (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    This article presents the capabilities of a SAR module during rescue operation planning and control. The Navi- Harbour SAR module was used during an exercise, which enabled an operator to plan and monitor the rescue operations of selected water areas. To present the basic capabilities of this module, we prepared a case for the SAR action for a man overboard in the Baltic Sea using actual available SAR resources in this area. For the basic assumptions of the scenario, a research plan was developed that included an assessment of the most probable position of a threatened unit, taking into account the weather conditions in this area.
  • Wójcik, Łukasz; Bulzak, Tomasz; Winiarski, Grzegorz; Szala, Mirosław (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    This article presents the results of computer simulations used to investigate the forming of a hollow coldworked forging with an outer flange. Numerical simulations were performed in Deform 2D/3D using a calculation module for axial-symmetric cases. A ϕ57×12.5 mm tube-shaped billet from 42CrMo4 grade steel was used. The forming process involved two and three stages, consisting of extrusion the shaft portion and forging the flange. The objective of this research was to determine the accuracy of the forming process used to produce the hollow part. This technology was analyzed using the effective strain distributions, the Cockcroft-Latham fracture criterion values, and the forming force progression. The results showed that it was possible to use this three-stage process to forge elements from a tube-shaped billet.
  • Szelangiewicz, Tadeusz; Żelazny, Katarzyna (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    In this paper, an experimental model has been developed to study an unmanned ship. Two aft azimuthal propellers and two bow tunnel thrusters were used to propel the ship. In order to develop algorithms and a computer program to control the model, it is necessary to determine the hydrodynamic characteristics of the propellers installed in the model. The propellers are very small; therefore it is impossible to use approximate methods of calculating the thrust of the ship’s propellers. The characteristics of the thrust of the propellers installed in the model were measured experimentally. This paper has given a description of the test stand and the results of the measurement of the thrust forces of the propellers installed in the model of an unmanned ship.
  • Sakaki, Abdollah; Kerdabadi, Mohsen Sadeghian (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    Computational fluid dynamics (CFD) has progressed rapidly in the past fifty years and is now used in many industrial fields, such as air, space, and marine engineering. CFD has an irreplaceable role in marine design and scientific research, and its applications within this field continue to grow with the development of computers. CFD is used to quickly and inexpensively simulate fluid behaviour using the Reynolds Averaged Navier–Stokes (RANS) equations to calculate hydrodynamic coefficients, which are needed in manoeuvrability studies of underwater vehicles (UWV). Here, these computations are performed for six geometrical shapes that represent typical autonomous underwater vehicles (AUVs) currently in use. Resistance test simulations at up to 20o drift angles were conducted for AUVs with different length-to-diameter ratios. The results were compared with the experimental data and current quasi-experimental relationships, which suggested that the CFD predictions were adequately precise and accurate. These predictions indicated that there was a non-linear relationship between forces and moments and the lateral speed. Moreover, both linear and non-linear hydrodynamic coefficients were calculated.
  • Nazemian, Amin; Ghadimi, Parviz (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    This paper investigates improving the leading-edge of a hydrofoil with sinusoidal protuberances based on its hydrodynamic performance. The original hydrofoil geometry was inspired by the leading edge of the flipper of a humpback whale. A multi-step optimization process was performed for a 634-021 hydrofoil. The free-form deformation technique defined the shape parameters as a variable design, and these parameters included the amplitude of the leading-edge protuberances, which ranged from 0 to 20% of the chord length, and the corrugate span, with 3 and 4 crests. The flow characteristics of a parametric hydrofoil were examined using a CFD solver, and the lift, drag, and lift-to-drag ratio (L/D) were computed as responses to the optimization cycle. To accomplish this, two design study methods were sequentially applied at different angles of attack. A full factorial design sweep tool was applied that went through all parameter value combinations, and an RBF-based surrogate model was constructed to investigate the system behavior. The results indicated the existence of an optimum design point, and the highest L/D ratio was determined to be 10.726 at a 12° angle of attack.
  • Motallebi, Mohammad; Ghafari, Hamidreza; Ghassemi, Hassan; Shokouhian, Mehdi (Scientific Journals Maritime University of Szczecin, Zeszyty Naukowe Akademia Morska w Szczecinie, )
    In this paper, the second-order hydrodynamic force on fixed and floating tandem cylinders has been calculated and different parameters have been taken into consideration. An incident wave is diffracted by the fixed cylinder, and as a result low-frequency waves radiate toward the floating cylinder and cause low-frequency second-order hydrodynamic forces to act on the surface of the floating cylinder. The interactions between the fixed and floating cylinders have been investigated by changing the distance between them, as well as the draft and radius of the floating cylinder. By employing perturbation series analysis over the wetted surface, the second-order wave excitation force has been calculated. The maximum force applied on the floating cylinder becomes non-dimensional when considering it with and without the fixed cylinder. The results showed the effect that the existence of the fixed cylinder had on the increase in the second-order forces is quite evident where, for a significant parameter of the floating cylinder, the force in the heave direction was enhanced by up to 1.55 times.

Search repository

Advanced Search


My Account

RSS Feeds