Nauka – Technika – Technologia : seria wydawnicza AGH. Tom 8

AGH Space Systems stands as a student-driven organization situated within the AGH University of Krakow, Cracow, Poland. At present, the team is fully engrossed in the development of Poland’s first bi-liquid propellant rocket. Named the “Turbulence” rocket, its propulsion is entrusted to the one-of-a-kind Z4000 engine, utilizing ethanol and nitrous oxide as its propellants. Drawing from their adeptness in hybrid rocket technology, the team ingeniously devised the Z4000 propulsion system, distinguished by its $N_{2}O$ self-pressurization cycle, elegantly embodied through a piston-dependent pressure vessel solution. Additionally, the team incorporated a composite combustion chamber into the system’s architecture. These pioneering elements, among others, firmly position this nitrous oxide-powered demonstrator as a standout contender for prospective applications within the space industry.

Book Chapter

Open Access

Frequency estimation in electric power system measurements

(Wydawnictwa AGH, 2023) Duda, Krzysztof; Barczentewicz, Szymon; Burza, Rafał; Borkowski, Dariusz; Bień, Andrzej; Gawędzki, Wacław; Marszałek, Zbigniew; Nabielec, Jerzy; Turcza, Paweł; Wetula, Andrzej; Zieliński, Tomasz

The paper investigates the performance of recently proposed frequency estimation methods in the presence of typical power system measurements disturbances, i.e. sinusoids and additive noise. The tests are conducted for the polyphase Prony method, the polyphase smart DFT, and the discrete-time frequency-gain transducer. Considered methods are capable of unbiased one-cycle frequency estimation. The robustness against disturbances is obtained by the application of the proposed prefilter. Consider methods with the initially filtered measurement signal perform significantly better than the standard PMU (phasor measurement unit) P class and M class signal processing models.

Book Chapter

Open Access

Analiza anizotropii właściwości mechanicznych stopu magnezu typu WE43

(Wydawnictwa AGH, 2023) Dudziński, Michał; Waląg, Michał; Kula, Anna

The article presents experimental work on the anisotropy aspects of the mechanical properties of WE43 alloy and technically pure magnesium (99.95%) obtained by hot extrusion. The experimental work includes structural and phase characterisation of as-extruded materials and uniaxial compression tests conducted parallel and perpendicular to the extrusion direction. Complementary studies of the macrotexture of materials before and after plastic deformation were carried out. Based on received results the degree of anisotropy of the mechanical properties of the tested materials was determined. The texture was identified as an important factor determining the activation of particular deformation mode of the materials after extrusion. Keywords: WE43 alloy, anisotropy, texture, compression test, microstructure

Book Chapter

Open Access

Badanie bezpieczeństwa rurociągu ze względu na uderzenie hydrauliczne

(Wydawnictwa AGH, 2023) Fąfara, Zbigniew

The paper presents the results of a study of the effect of hydraulic hammer on the sudden increase in internal pressure in the “Druzhba” trunk pipeline transporting crude oil. The subject of the investigation is a path of one section of the pipelines with a length of 103.5 km. During the analysis, nine selected events were taken into account, during which one of the pump stations was completely stopped. Practice shows that the effects of hydraulic hammer occurring in pipeline systems transporting liquid media are the cause of their failure in more than 80% of cases. The results of direct measurements of pressure changes inside the pipeline accompanying a complete stoppage of the flow of crude oil indicate an up to three-fold increase in the pressure of the transported medium at the entrance of the stopped pump station, which is particularly dangerous and may result in leakage of the “Druzhba” pipeline. Despite the recent changes in the market for crude oil supplies to Europe and the reduction of its import from Russia due to the aggression against Ukraine, the trunk pipeline “Druzhba” is currently still the primary installation supplying oil to Ukraine, Slovakia, the Czech Republic and Hungary, while in Poland its part is used to transport oil to refineries located in the eastern part of Germany. The main pipeline “Druzhba” was built 60–70 years ago and currently its technical condition may leave much to be desired, so its safety is a very important issue.

Book Chapter

Open Access

Aerial SLAM algorithm with global alignment using satellite imagery

(Wydawnictwa AGH, 2023) Karbowski, Jakub; Bartoszewski, Bartosz; Kokot, Daria; Kwiecień, Michał Jan; Turlej, Tymoteusz

Simultaneous localization and mapping (SLAM) algorithms can be used in aerial vehicles with a down-facing camera for navigation and terrain mapping. However, they suffer from an incremental position error. Each neighbouring image pair match introduces an alignment error which accumulates to a global position error proportional to the map size. By using a reference satellite image map this error can be reduced to a constant factor. This work proposes a novel image alignment algorithm called Embed Match which can be applied to any SLAM algorithm. Embed Match uses a neural network to represent a map region as a field of embedding vectors which are a semantic representation of the area. By comparing the embedding fields of a satellite image and the camera image, an alignment function is defined. Maximising this function leads to image alignment. The proposed algorithm shows a radically different approach from keypoint-based alignment methods which usually struggle with matching drastically different images, such as satellite and real camera images.

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Rights: AGH Licence (University Press)

Licencja AGH (University Press) - Fair use of copyrighted works

URI

https://repo.agh.edu.pl/handle/AGH/106471

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