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EN
The paper presents a synthetic characterization of modern methods of manufacturing or regenerating machine elements. Considered methods are machining and additive methods, in particular 3D printing in the FDM/FFF technique. For the study, the authors made samples of the holder bracket using selected methods. Samples made by machining operations, 3D printing with various filling were tested. The paper contains a technical and economic analysis of the production of a holder bracket using the discussed methods. The dynamics of steel and FDM/FFF printed samples were also assessed by determining their resonance curves. The vibration magnification fac-tors were analyzed - the quotient of the vibration amplitudes in the resonance to the static deformations that occurred under the influence of the constant force and the location of the vibration resonances - the natural frequencies for individual vibration modes. The study's main objective is to assess the possibility of emergency changing the manufacturing technology of selected machine components. The authors were interested in partially replacing costly and not environmentally friendly milling with 3D printing. Machine elements can be manufactured by printing in classical machine building and emergency conditions to replace a damaged component temporarily (e.g., on a ship, for the time of arrival at a port or shipyard). The main assumption guiding the authors during the preparation of this publication was the analysis of the possibility of using the production of "ad hoc" prepared spare parts and their use in the event of a lack of access to parts made of the intended materials.
EN
There are numerous non-destructive methods in welded joints investigation, but the most promising, especially in applications with steady monitoring of the structure, is the vibro-diagnostic approach. In the course of the research work, the responses were obtained and detected by accelerometers, providing valuable diagnostic information, which later was mathematically processed in the field of time or frequency. The mathematical processing aimed to distinguish significant characteristics embedded in the processes typical of the investigated joints and allow an assessment of how they were made. For this purpose, two methods were proposed, based on determining the logarithmic decrement as a function of time. Due to the complicated course of the impact responses, the method of calculating the logarithmic decrement has been suggested, involving the approximation of responses with various functions. According to the research, the analysis of changes in the logarithmic decrement as a function of time applied to welded plates was proposed, as it enables the initial assessment of joint quality.
EN
The article shows the results of the preparatory steps taken to create the artificial intelligence used in the automatic recognition of defects in ship thin-walled structures. The above steps are used to create a university private cloud and a computer system maintaining a dataset of vibration signal samples. In the article, a prototype of the private cloud was designed and developed, a model of the vibration sample was prepared, and a microservice was designed aimed at sharing the obtained data. The article demonstrates the results of the completed development.
PL
W artykule przedstawiono wyniki przeprowadzonych działań przygotowawczych do stworzenia sztucznej inteligencji wykorzystywanej w automatycznym rozpoznawaniu defektów okrętowych konstrukcji cienkościennych. Przeprowadzone kroki służą stworzeniu uczelnianej chmury prywatnej oraz systemu informatycznego utrzymującego zbiór danych próbek sygnałów drganiowych. W ramach artykułu zaprojektowano oraz stworzono prototyp chmury prywatnej, przygotowano model próbki drganiowej oraz zaprojektowano mikroserwis służący udostępnianiu uzyskanych danych. Artykuł przedstawia wyniki wykonanej pracy.
EN
The article presents results of vibration tests of thin-walled plates used in shipbuilding for plating hulls of vessels. The conducted tests were aimed at determining the possibility of using measurements of vibration acceleration recorded on the tested objects as parameters enabling the detection of damages in the performed welded joints. Seven plates were compared, six of which had joints in different technical conditions, and one was a board without a weld. The quality of the welds was verified using X-ray methods. The adopted research methodology and the obtained results were presented.
PL
W artykule przedstawiono wyniki badań drganiowych płyt cienkościennych wykorzystywanych w okrętownictwie jako poszycie kadłubów jednostek pływających. Przeprowadzone badania miały na celu określenie możliwości stosowania pomiarów przyspieszeń drgań rejestrowanych na badanych obiektach jako parametrów umożliwiających wykrycie uszkodzeń w wykonanych połączeniach spawanych. Porównano siedem płyt, z czego sześć miało spoiny w różnym stanie technicznym, a jedna była bez spawu. Jakość spoin zweryfikowana została metodami RTG. Przedstawiono przyjętą metodykę badawczą oraz uzyskane wyniki.
EN
This paper presents a method of lowering the processor’s voltage and temperature in which the computer operates by performing an operation called undervolting. By using undervolting it is possible to reduce electricity consumption and the amount of heat generated by computer workstations by up to 30%. This problem is particularly relevant for institutions that use a large number of computers. The more the computers are subjected to the higher computational load, the more effective the mechanism of undervolting is. Undervolting the processor does not reduce its performance, but lowers its operating temperature, has a positive impact on its life span and power consumption. Maintaining a low temperature of operation for computer hardware is essential to reduce operating and repair costs. The paper also presents the results of environmental research aimed at assessing the validity and effectiveness of undervolting.
PL
W pracy przedstawiono metodę obniżania napięcia procesora i temperatury pracy komputera poprzez wykonanie operacji zwanej undervoltingiem. Przez zastosowanie undervoltingu można obniżyć nawet o 30% zużycie energii elektrycznej i ilość wydzielanego ciepła przez stanowiska komputerowe. Problem ten jest szczególnie istotny w przypadku instytucji, które korzystają z dużej liczby komputerów. Skuteczność mechanizmu jest tym większa im komputery poddane undervoltingowi są bardziej obciążone obliczeniowo. Wykorzystywanie undervoltingu w konfiguracji procesora nie zmniejsza jego wydajności, a obniża jego temperaturę pracy, wpływa pozytywnie na jego żywotność i zużycie energii elektrycznej. Utrzymanie dobrej kultury pracy sprzętu komputerowego jest kluczowe, by obniżyć koszty eksploatacji oraz napraw. W pracy przedstawiono również wyniki badań środowiskowych, których celem była ocena zasadność i efektywności stosowania undervoltingu.
EN
Increasingly popular remote work requires the use of modern network technologies to provide employees in a remote location with access to the company’s IT resources. The answer to the needs of remote access to files and server services can be the use of clouds and VPS. However, this involves high costs and requires entrusting the enterprise’s data to the providers of these services. Both for reasons of data security and too high costs, enterprises sometimes cannot use these technologies. The solution to the problem may be the use of encrypted VPN tunneling, which allows the device to be connected at a remote location to the company’s local network and use its resources as if it was connected to the local network with physical transmission medium.
EN
Creating the required IT infrastructure to enable the ability for comfortable remote working is not an easy task. Improper configuration can create the possibility of taking over the whole bandwidth of the link by one device. Increasing bandwidth introduces extra costs and does not completely eliminate the problem – it will be more difficult to take over the whole bandwidth, but it is still possible. The solution to the problem may be the use of clouds and VPS, but it is associated with high costs and the need to entrust company data to providers of these services. Due to security and too high costs, this may not be an optimal solution. An alternative solution may be to use QoS along with PCQ. This mechanism allows to ensure equal division of the bandwidth between the devices under its control. With an appropriate configuration, QoS can eliminate the problem of taking over the whole bandwidth and ensure equal access to resources.
8
Content available Containerization of Server Services
EN
Businesses are increasingly confronted with server-related problems. More and more, businesses are enabling remote working and need to rely on network services. The provision of network services requires rebuilding the network infrastructure and the way employees are provided with data. Web applications and server services use common dependencies and require a specific network configuration. This often involves collisions between network ports and common dependencies’ configuration. This problem can be solved by separating the conflicting applications into different servers, but this involves the cost of maintaining several servers. Another solution may be to isolate applications with virtual machines, but this involves a significant overhead on server resources, as each virtual machine must be equipped with an operating system. An alternative to virtual machines can be application containerization, which is growing in popularity. Containerization also allows to isolate applications, but operates on the server’s native operating system. This means eliminating the overhead on server resources present in virtual machines. This article presents an example of web application containerization.
PL
W pracy przedstawiono metodę konfiguracji sieci lokalnej na potrzeby laboratoriów komputerowych. Zastosowano QoS (ang. Quality of Service) z PCQ (ang. Per Connection Queueing) w celu zapewnienia studentom dostępu o równej przepustowości do serwerów laboratoryjnych. Metoda ta umożliwia zarówno priorytetyzację konkretnego ruchu sieciowego, ograniczanie przepustowości do konkretnych, z góry ustalonych wartości, jak i gwarantowanie prędkości transferu na poziomie przepływności pozostałych użytkowników. Metoda ta jest skalowalna i możliwa do zastosowania w większości routerów programowalnych.
EN
The paper presents a method of configuring the computers laboratiories’ local network. The QOS with PCQ was used in order to guarantee an equal bandwith for students connecting to laboratories’ servers. This method allows both prioritizing specific type of network traffic, limiting bandwith to pre-established values and guarantiing the same bandwith for every user. This metod is scalable and can be applied by using most of programmable routers. A basic configuration of QoS with PCQ that made clients get equal bandwith was presented in the second chapter. This configuration consisted of one parent query that created a structure in which sub-queries configured with PCQ were placed. The third chapter showed a configuration that pioritized traffic on specific port (port 22) above other taffic. This configuration was also configured with PCQ to share the bandwith equaly for every client that made prioritized traffic. In order to create the configuration, firewall mangle rules were created to mark connections (upload and download) and to mark packets (packets send or received on port 22 and packets not send or received on this port). The marks were used to allow QoS to select the packets that were ment to be prioritized and give them the highest priority. In collaboration with PCQ the configuration prioritized port 22 traffic while splitting the bandwith equaly amongst clients.
PL
W pracy przedstawiono metodę tworzenia infrastruktury laboratoryjnej pozwalającej, za pośrednictwem serwera, na sieciowe uruchamianie (ang. network booting) różnych programów na stanowiskach laboratoryjnych. Prezentowana metoda wykorzystuje oprogramowanie PiNet do stworzenia instancji systemu operacyjnego Raspbian na serwerze. Metoda ta wykorzystuje także odpowiednio przygotowane jednostki startowe (ang. boot file) umieszczane na kartach pamięci w komputerach typu Raspberry Pi. Dzięki tej konfiguracji, zaraz przy uruchomieniu, urządzenia te łączą się z serwerem i użytkują serwerową instancję Raspbiana. Dla każdego użytkownika pracującego na urządzeniach przygotowywane jest osobne konto, co pozwala na jednoczesną pracę wielu użytkowników w trybie multi-user-mode.
EN
The paper presents a metod of creating laboratory infrastructure that allows network booting from a laboratory server. This method uses PiNet software to create a single Raspbian OS instance on the server. By putting network boot files on Raspberry Pis memory cards, it allows Raspberry Pis to use the single Raspbian OS instance that was placed on the server. For every user working on the Raspberry devices there is a user account created. This metod allows multiple users to be logged in at the same time in spite of having only one instance of Raspbian OS. Having only one instance of Raspbian OS makes configuring the laboratory infrastructure easier. The Raspbian placed on the server can be chrooted at any moment to install additional applications, execute bash scripts or edit configuration files. Properly configured Raspbian can be used |to teach programming, networking and managing databases. Moreover Raspbian can be used as a terminal that uses SSH to work on a server ex. to execute queries on PostgreSQL server.
EN
The article presents methods for the location of leakages in heating pipelines. The advantages and disadvantages of each of the described methods are presented. The exploitation and modernization of the actual heating network in the city of up to 30,000 inhabitants over the space of 10 years have been characterized. The examined heating network was analyzed for the degree and categories of malfunctions occurring in the examined time space in the network and impact on the natural environment was determined. The article also examines the impact of various factors, such as the amount of make-up water, the amount of heat required to heat the supplementary carrier, the total cost of heat to replenish the carrier, networks total disruption and the amount of water exchange in the system and its impact on the natural environment. At the same time, an assessment of the impact of the modernization of the heating network combined with its munition to reduce the impact of these factors on environmental protection was made.
PL
W artykule przedstawiono metody lokalizacji nieszczelności rurociągów ciepłowniczych. Przedstawiono wady i zalety każdej z opisanych metod. Scharakteryzowano eksploatację i modernizację rzeczywistej sieci ciepłowniczej w mieście do 30 tysięcy mieszkańców na przestrzeni 10 lat. W badanej sieci ciepłowniczej przeanalizowano stopień i kategorie awarii występujących w badanej przestrzeni czasu w sieci oraz określono ich wpływ na środowisko naturalne. W artykule zbadano również oddziaływanie rożnych czynników, takich jak: ilość wody uzupełniającej, ilość ciepła do podgrzania nośnika na uzupełnienie, koszt łączny ciepła przeznaczony do uzupełnienia nośnika, zład łączny sieci oraz ilość wymian wody w systemie i jej wpływ na środowisko naturalne. Równolegle, podjęto ocenę wpływu modernizacji sieci ciepłowniczej, połączonej z jej uzbrojeniem, na zmniejszenie oddziaływania wymienionych czynników na ochronę środowiska.
EN
Among structural health monitoring (SHM) methods of thin-walled structures, a vibrodiagnostic method is one of the most promising. The accelerometer recorded responses provide diagnostic information that requires mathematical processing to extract the essential dynamic characteristics. The authors have been looking for new parameters - diagnostic benchmarks which can be applied to non-destructive, automatic testing of thin-walled marine structures (especially their welded joints) like ship hulls. All characteristics have been based on recorded data generated during the vibration tests of welded joints with and without failures. For this purpose, the authors proposed method based on: FFT windowing analysis, benchmark with using 2D or 3D time – frequency dynamic characteristics and the determination of damping decrement in function of time. The work presents the algorithm and exemplary results obtained from the application of proposed method to several selected sample plates with different type of welds.
EN
Thin-walled structures are very popular in industries, especially in the field of shipbuilding. There are many types of equipment and structures of ships, which are made up of thin-walled structures such as hull, deck and superstructure. Therefore, the analysis and understanding of the static and dynamic characteristics of a thin-walled structure are very important. In this article, we focus on vibration analysis of a typical thin-walled structurerectangular plate, a basic structure of the hull. Vibration analysis of a rectangular thin plate is conducted by two methods: numerical modelling method of the finite element on Patran-Nastran software platform and experimental method implemented in the laboratory of Gdynia Maritime University. Thin rectangular plate is fixed one end by four clamping plates and is modelled with finite elements and different meshing densities. The numerical model of thin rectangular plate is divided into four cases. Case 1, thin rectangular plate, and clamping plates are modelled with two-dimensional elements. Case 2, the rectangular thin plate is modelled with two-dimensional elements; the clamping plates are modelled with three-dimensional elements. Case 3, both the rectangular thin plate and clamping plates are modelled with three-dimensional elements. Case 4, the rectangular thin plate, and clamping plates are modelled with three-dimensional elements with larger mesh density to increase the accuracy of the calculation results. After that, the results of vibration analysis according to the numerical modelling method on Patran-Nastran software platform for these cases were compared with the measurement results. From there, assess the accuracy of analysis results of selected numerical model methods and the ability to widely apply this numerical model method to other marine structures
EN
The article presents a methodology of non-destructive diagnostic vibratory tests of welded plates with geometrical parameters that classify them into a group of thin-walled panels. On the basis of such plates, most ship constructions are created. In previous works, the authors dealt with the study of welded joints in plates with significant thicknesses and developed for them a number of methods for assessing the quality of welded joints. Vibrodiagnostics is a NDT method that allows the use of a variety of techniques and tools. It enables measurements to be made in both a contact and non-contact way depending on the requirements of the structure and the environment. Vibrodiagnostic method is one of the most modern NDT methods, which uses modern measurement tools and computer analysis of data. On the basis of the developed methods, the authors intend to verify their application to plates from real welded constructions, which will be performed in typical shipyard conditions by welders. Such tests are important due to their use for the construction of a real SHM ship construction monitoring system. These methods allow for the examination of the condition of ships’ structural plates and can detect defects in welded joints that prevent ships from operating under severe sea conditions. The article presents the laboratory stand, the sensor layout, results, and their initial analysis.
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