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1

Wpływ ultradźwięków na parametry cieczy węglowodorowych

Bieszczak Hanna, Halat Zbigniew, Szpilman Sylwia, Kowalaszek Anna, Gramatyka Grażyna

Nafta-Gaz

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2024

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R. 80, nr 6

335--342

PL

W niniejszym artykule przedstawiono wyniki prac prowadzonych w ramach projektu pt. Innowacyjna technologia monitoringu sejsmoakustycznego oraz sejsmostymulacji (M2S), nr POIR.01.01.01-00-0015/17-00. Opisano wpływ ultradźwięków na parametry fizykochemiczne dwóch różnych cieczy węglowodorowych – ropy naftowej i oleju transformatorowego. Na każdą badaną próbkę cieczy działano falami ultradźwiękowymi o gęstości mocy akustycznej w zakresie 4–15 W/cm2 , po czym analizowano gęstość i lepkość kinematyczną. W ramach prowadzonych badań pomiary gęstości wykonywano za pomocą szklanych areometrów, natomiast badania lepkości kinematycznej przeprowadzono z wykorzystaniem automatycznego lepkościomierza HVM 472. Badania parametrów fizykochemicznych wykazały zmienność właściwości ropy naftowej i oleju transformatorowego po zastosowaniu ultradźwięków. Pod wpływem działania ultradźwięków nastąpiło zmniejszenie gęstości i lepkości kinematycznej badanych cieczy węglowodorowych. Dzięki tym badaniom ustalono charakterystykę fali ultradźwiękowej, która może najlepiej wpływać na parametry ropy naftowej w przypadku jej wydobycia ze złoża. Charakteryzująca falę ultradźwiękową gęstość mocy akustycznej na poziomie 12 W/cm2 najkorzystniej wpływa na zmniejszenie lepkości oleju transformatorowego. W przypadku ropy naftowej najkorzystniejszą gęstością mocy akustycznej pozwalającą na największe obniżenie lepkości jest 11 W/cm2 . Takie parametry fali akustycznej okazały się najbardziej optymalne ze względu na maksymalny spadek lepkości badanych cieczy przy najbardziej ekonomicznych nastawach symulatora rozkładu faz. Zarówno w badaniach oleju transformatorowego, jak i ropy naftowej stopniowe zwiększanie gęstość mocy akustycznej ultradźwięków nie powodowało przegrzania układu w badanym przedziale czasowym.

EN

This article presents the results of work carried out within the framework of the Innovative seismoacoustic monitoring and seismostimulation (M2S) technology, project, No. POIR.01.01.01-00-0015/17-00. The effect of ultrasound on the physicochemical parameters of two different hydrocarbon liquids – crude oil and transformer oil – is described. Ultrasonic waves with acoustic power density in the range of 4–15 W/cm2 were applied to each test sample, after which the density and kinematic viscosity were analysed. As part of the research, density measurements were carried out using glass areometers, while kinematic viscosity tests were carried out using an automatic viscosity meter HVM 472. The study of physicochemical parameters showed the variation in the properties of crude oil and transformer oil after application of ultrasound. Under the influence of ultrasound, the density and kinematic viscosity of the hydrocarbon liquids studied decreased. Thanks to these studies, the characteristics of the ultrasonic wave that best affects the parameters of crude oil, conducive to its extraction from the reservoirs, were established. The acoustic power density of 12 W/cm2 , which characterizes the ultrasonic wave, has the most favourable effect on reducing the viscosity of transformer oil. For crude oil, the most favourable acoustic power density allowing the greatest viscosity reduction is 11 W/cm2 . Such acoustic wave parameters proved to be the most optimal due to the maximum viscosity reduction of the studied fluids at the most economical settings of the phase distribution simulator. In both transformer oil and crude oil tests, the gradual increase of the acoustic power density of ultrasound did not cause overheating of the system in the studied time interval.

2

Wpływ włókien szklanych na wybrane właściwości autoklawizowanych materiałów wapienno-piaskowych

Jasińska Iga, Dachowski Ryszard, Jaworska-Wędzińska Monika

Materiały Budowlane

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2024

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nr 9

17--20

PL

Celem badań było określenie wpływu zawartości włókien szklanych z powłoką cyrkonową (AR) o długości 24 mm, na wybrane właściwości autoklawizowanych próbek wapienno-piaskowych, tj. gęstość, absorpcja wody i wytrzymałość na ściskanie, wykonanych na bazie mieszanki wapienno-piaskowej. Dokonano również obserwacji mikrostruktury za pomocą SEM. Badania przeprowadzono z użyciem włókien, których udział w masie wynosił od 1 do 5%. Otrzymane wyniki badań dały podstawę do stwierdzenia, że próbki zawierające w masie 1 – 3% włókien szklanych z powłoką cyrkonową wykazują wyższą wytrzymałość na ściskanie w odniesieniu do próbek referencyjnych, oraz wskazują kierunek dalszych badań.

EN

The aim of the study was to determine the effect of zirconia-coated (AR) glass fibers, with a length of 24 mm, on selected properties of autoclaved lime-sand samples, such as density, water absorption, and compressive strength. Microstructure observations were also conducted using SEM. The research was carried out using fibers with a mass content ranging from 1% to 5%. The obtained results provided the basis for concluding that samples containing 1 – 3% zirconia-coated glass fibers by mass exhibit higher compressive strength compared to the reference samples, and they indicate the direction for further research.

3

Influence of Melt Properties on the Dendritic Structure of Steel Castings

Aftandiliants Y., Gnyloskurenko Svyatoslav, Meniailo H., Khrychikov V.

Archives of Foundry Engineering

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2024

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Vol. 24, iss. 1

5--13

EN

The paper presents the experimental results on the determination of melt parameters such as the energy of the boundary, contact angle, density and kinematic viscosity of low and medium alloy steels at different temperatures, as well as the dispersion of their dendritic structure in solidified castings. The analysis of the data obtained allowed revealing using mathematical models the influence of the chemical composition and temperature of melts on their properties and the dendritic structure of castings. It was established the variation of the melt parameters depending on the particular chemical elements of steels as C, Si, Mn, O, P, V, Cr. The established analytical dependences shown that increasing density and viscosity contributes to the dispersion of the dendritic structure and viscosity is of the major effect. The derived quantitative patterns allows to evaluate structure formation of cast structural low and medium alloy steels.

4

Evaluation of Permeability Models for Foundry Molds and Cores in Sand Casting Processes

Sundaram Dinesh, Matsushita Taishi, Belov I., Diószegi Attila

Archives of Foundry Engineering

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2024

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Vol. 24, iss. 1

94--106

EN

Predicting the permeability of different regions of foundry cores and molds with complex geometries will help control the regional out gassing, enabling better defect prediction in castings. In this work, foundry cores prepared with different bulk properties were characterized using X-ray microtomography, and the obtained images were analyzed to study all relevant grain and pore parameters, including but not limited to the specific surface area, specific internal volume, and tortuosity. The obtained microstructural parameters were incorporated into prevalent models used to predict the fluid flow through porous media, and their accuracy is compared with respect to experimentally measured permeability. The original Kozeny model was identified as the most suitable model to predict the permeability of sand molds. Although the model predicts permeability well, the input parameters are laborious to measure. Hence, a methodology for replacing the pore diameter and tortuosity with simple process parameters is proposed. This modified version of the original Kozeny model helps predict permeability of foundry molds and cores at different regions resulting in better defect prediction and eventual scrap reduction.

5

Physical properties of plant extracts with biostimulant potential produced using cold plasma and low-pressure microwave discharge

Krawczuk Anna, Ogrodniczek Jacek, Bohata Andrea, Bartos Petr, Olšan Pavel, Findura Pavol, Kocira Sławomir

Agricultural Engineering

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2024

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Vol. 28, No. 1

277--285

EN

The changing climate, causing more frequent abiotic stresses, has generated interest in products that can mitigate the negative impacts of these changes. One such group of preparations includes plant extracts with biostimulant potential, produced using various methods and techniques, including cold plasma and low-pressure microwave discharge. However, there is limited research on how production methods and techniques affect the physical properties of biostimulants, such as density, viscosity, and surface tension. This study aimed to evaluate the impact of the manufacturing process on these properties. The biostimulant was produced via hot water extraction using either cold plasma or low-pressure microwave discharge. Results showed that neither method reduced the surface tension of the biostimulants, but they significantly influenced the viscosity and density. Given these changes in physical properties, further research on droplet spectrum and plant coverage during application is necessary to determine the optimal technical parameters for effective spraying.

PL

Zmieniający się klimat powodujący coraz częściej występowanie stresów abiotycznych wpłyną na zwiększenie zainteresowania preparatami mogącymi niwelować negatywne skutki tych zmian. Jednymi z takich preparatów są ekstrakty roślinne o potencjale biostymulującym wytwarzane rożnymi metodami i technikami z wykorzystaniem m.in. zimnej plazmy czy niskociśnieniowego wyładowania mikrofalowego. Jest jednak niewiele doniesień dotyczących wpływu metody czy techniki wytwarzania biostymulatorów na ich właściwości fizyczne takie jak gęstość, lepkość i napięcie powierzchniowe. Dlatego też w pracy podjęto się oceny wpływu procesu wytwarzania biostymulatora na ww. cechy. Biostymulator wytwarzano metodą ekstrakcji wodnej na gorąco z zastosowaniem zimnej plazmy lub niskociśnieniowego wyładowania mikrofalowego. Badania wykazały, że zastosowanie w procesie wytwarzania zimnej plazmy lub niskociśnieniowego wyładowania mikrofalowego nie wpłynęło na zmniejszenie napięcia powierzchniowego biostymulatorów, ale wpłynęło istotnie na lepkość oraz gęstość wytwarzanych biostymulatorów. W związku ze zmianą właściwości fizycznych takich jak lepkość i gęstość w wyniku zastosowania zimnej plazmy lub niskociśnieniowego wyładowania mikrofalowego należy przeprowadzić dalsze badania dotyczące spektrum kropel oraz stopnia pokrycia roślin podczas zabiegu w celu doboru odpowiednich parametrów technicznych warunkujących jak najlepsze wykonanie oprysku.

6

Evaluation of some thermophysical properties of sn500 lubrication oil blended with SIO2, AL2O3 and TIO2 nano-additives, using fuzzy logic

Sankar E., Duraivelu K.

Acta Mechanica et Automatica

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2024

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Vol. 18, no. 2

352--360

EN

Nano-additives are generally blended with the base lubricant oil, to enhance the lubricant characteristics such as wear, coefficient of friction (CoF), thermal conductivity, density, and flash and fire points of the lubricant. In this research, nano-additives of SiO2, Al2O3 and TiO2 are blended with the base SN500 oil with different proportions of mixture. When these three nanoparticles are used together in base oil, they enhance most of the desirable properties of a lubricant; 27 samples with three different levels of a mixture of nano-additives are identified using factorial design of experiments. The experimental outcomes for the selected three characteristics of interest of density, flash point and fire point are determined. Conducting experiments for ‘n’ number of samples with different proportions of mixture of nano-additives is a cumbersome, expensive and time-consuming process, in order to determine the optimum mix of nano-additives for the desirable level of characteristics of interest. In this research, attempt has been made to apply fuzzy logic to simulate a greater number of samples with different proportions of a mixture of three nano-additives with the respective outcomes of characteristics of three thermophysical properties. Out of the numerous samples simulated using fuzzy logic, the sample with the optimum mix of three nano-additives of SiO2, Al2O3 and TiO2 blended with the base oil is identified for the desirable level of characteristics of interest of density, flash point and fire point. The values of the identified sample are found to be at the desirable level of 0.9008 gm/ml, 231°C and 252°C, respectively.

7

The influence of carbide reinforcement on the properties of sintered aluminium alloy matrix composites

Szewczyk-Nykiel Aneta

Technical Transactions

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2023

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Vol. 120, iss. 1

art. no. e2023005

EN

Based on the commercial aluminium alloy powder blend (Alumix 431D) metal matrix composites reinforced with particles of SiC as well as TiC were produced by conventional powder metallurgy technology and the effect of the type and amounts of reinforced particles on the selected properties and microstructure of sintered composites were investigated. In particular, the densification behaviour, the wear resistance and the corrosion resistance in 3.5% NaCl solution were identified. It was stated that both the type and the weight fraction of carbide used as particulate reinforcement have a great impact on the properties of aluminium alloy matrix composites. It was shown that the introduction of titanium carbide has a more favourable effect on the properties of sintered Alumix 431D matrix composites in comparison to silicon carbide and the optimum content of TiC in composite is 4 wt. % due to the highest hardness, wear resistance (wear rate of 2.865·10 ̄ ³ mm³/m) and simultaneously the best corrosion resistance (corrosion rate of 0.005 mm/year).

8

Proekologiczne kruszywo z odpadów tworzyw sztucznych jako alternatywa kruszywa naturalnego do betonów lekkich

Prusiel Jolanta Anna, Bujnarowski Kevin

Przegląd Budowlany

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2023

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R. 94, nr 11-12

144--148

PL

W artykule opisano możliwość wykorzystania w budownictwie poprodukcyjnych odpadów plastikowych, takich jak folia zwykła i termokurczliwa. Wykorzystując specjalistyczną technologię, wytworzono kruszywo łamane o uziarnieniu do 8 mm z mieszanki materiałów syntetycznych PET/PVC/OPS (PPO). Materiały te pochodziły z odpadów generowanych podczas produkcji etykiet foliowych. W artykule przedstawiono wyniki badania właściwości kruszywa z recyklingu tworzyw sztucznych, takich jak gęstość nasypowa i ziaren, nasiąkliwość oraz parametry mechaniczne betonu. Przedstawiono również zdjęcia z mikroskopu skaningowego dla kruszywa z odpadów tworzyw sztucznych oraz dla betonu z jego zawartością. Zastosowanie ekologicznego kruszywa do betonu lekkiego wpłynie pozytywnie na ochronę środowiska naturalnego.

EN

The article describes the possibility of using post-production plastic waste, such as ordinary and shrink film, in construction. Using specialized technology, a crushed aggregate with a grain size of up to 8 mm was produced from a mixture of PET/PVC/OPS (PPO) synthetic materials. These materials were derived from waste generated during the production of film labels. In the article the results of testing the properties of the recycled plastic aggregate, such as bulk and grain density, absorbability and mechanical parameters of concrete, were presented. Scanning microscope images for aggregate made from plastic waste and for concrete with its content were also presented. The use of pro-ecological aggregate for lightweight concrete will have a positive impact on protection of natural environment.

9

Perspektywy zastosowania betonu hydraulicznego w budownictwie pozaziemskim ze względu na konsystencję mieszanki

Mrozek Magdalena, Mrozek Dawid

Przegląd Budowlany

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2023

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R. 94, nr 9-10

73--76

PL

Jednym z istotnych problemów przy projektowaniu bazy pozaziemskiej jest dobór odpowiedniego materiału konstrukcyjnego. Autorzy niniejszego artykułu przygotowują się do serii badań materiałów, których podstawą byłby symulant regolitu. Są one jednak kosztowne i wymagają dobrego przygotowania. Pierwszym etapem jest przeprowadzenie badań materiału znanego i łatwo dostępnego, jakim jest beton, w warunkach obniżonego ciśnienia. Artykuł prezentuje wyniki testów odpowiadających na pytanie, w jaki sposób konsystencja mieszanki betonowej dojrzewającej w próżni wpływa na parametry stwardniałego betonu, takie jak gęstość oraz wytrzymałość na ściskanie.

EN

One of the significant problems in the design of an extraterrestrial habitat is the selection of a suitable structural material. The authors of this paper are preparing for a series of material tests based on a regolith simulant. However, these are expensive and require good preparation. The first step is to test a material that is known and readily available, such as concrete, under reduced pressure. This article presents the results of experiments answering the question: how does the consistency of a concrete mixture matured in a vacuum affect the parameters of the hardened concrete, such as density and compressive strength.

10

Influence of the non-equilibrium state of real gases on their properties

Aliyev Vasif I., Aslanov Jamaladdin N., Nabiev Nadir I., Rahimova Mahluqa S.

Nafta-Gaz

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2023

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R. 79, nr 2

84--95

EN

This scientific work presents a study of areas of application and improvement for the Clapeyron–Mendeleev equation to determine the technological parameters of natural and associated petroleum gas under field conditions. As a result of scientific and practical research and laboratory work, the authors, based on the molecular kinetic theory of gases, developed and improved the Clapeyron– Mendeleev equations of state of real gases by adding some genuine parameters for natural and associated petroleum gases produced from oil and gas condensate fields. In this regard, two additional parameters are introduced in the Clapeyron–Mendeleev equation-relative density and relative velocity of gas: and this, as a new scientific result, helps determine any parameter from the seven included in the equation of state of natural and associated petroleum gases developed by the authors. Continuous technological process according to the system of “production, collection, preparation and transportation of products (oil + gas)”, including, separately in non-equilibrium conditions of “collection, preparation and transportation of gas” due to internal energy, causes a natural change in a wide range of basic technological parameters that contribute to frequent changes in the physical and chemical state of the gas. Therefore, this work establishes that one of the main tasks is to show the composition of natural and associated petroleum gas as a result of irreversible transformations of hydrocarbon and acidic components of its internal energy, as a result of which the gas is characterised by a number of patterns in the composition and distribution of components of various hydrocarbon and heterogeneous compositions (i.e., physically and chemically heterogeneous). In these conditions, a practical calculation of gas facilities (gas treatment point, selection of gas separators, field gas pipelines, compressor stations) is carried out to determine process parameters using the Clapeyron–Mendeleev equation of state for real gases, and the results show large errors. This proves once again that many authors have developed equations of state for real gases based on the results of laboratory studies with single-atomic and laboratory gases (hydrogen, nitrogen, oxygen, carbon dioxide, etc.). However, the authors here carried out laboratory studies with products and associated petroleum gas. According to the results of laboratory studies, the authors recommend an improvement of the equation of state of natural and associated petroleum gases.

PL

W pracy przedstawiono studium obszarów zastosowania i doskonalenia równania Clapeyrona–Mendelejewa do wyznaczania parametrów technologicznych gazu ziemnego i towarzyszącego gazu ropopochodnego w warunkach złożowych. W wyniku badań naukowych i praktycznych oraz prac laboratoryjnych autorzy, w oparciu o molekularną teorię kinetyczną gazów, opracowali i udoskonalili równania stanu gazów rzeczywistych Clapeyrona–Mendeleeva poprzez dodanie niektórych parametrów rzeczywistych dla gazu ziemnego i towarzyszących gazów ropopochodnych wydobywanych ze złóż ropnych i kondensatowych. W związku z tym do równania Clapeyrona– Mendeleeva wprowadzono dwa dodatkowe parametry – gęstość względną i prędkość względną gazu, co, jako nowy wynik naukowy, pozwala na wyznaczenie dowolnego parametru z siedmiu parametrów zawartych w opracowanym przez autorów równaniu stanu gazu ziemnego i towarzyszącego gazu ropopochodnego. Ciągły proces technologiczny zgodnie z systemem „produkcji, odbioru, przygotowania i transportu produktów (ropa + gaz)”, w tym osobno w warunkach nierównowagi „odbioru, przygotowania i transportu gazu”, ze względu na energię wewnętrzną powoduje naturalną zmianę w szerokim zakresie podstawowych parametrów technologicznych, które przyczyniają się do częstych zmian stanu fizykochemicznego gazu. Dlatego też przedmiotowa praca jako jedno z głównych zadań stawia przedstawienie składu gazu ziemnego i towarzyszącego mu gazu ropopochodnego powstałego w wyniku nieodwracalnych przemian węglowodorowych i kwasowych składników jego energii wewnętrznej, w wyniku czego gaz ten charakteryzuje się szeregiem prawidłowości pod względem składu i rozprzestrzenienia poszczególnych składników węglowodorowych (o niejednorodnym składzie pod względem fizycznym i chemicznym). W tych warunkach przeprowadzono praktyczne obliczenia dla instalacji gazowych (punkt uzdatniania gazu, dobór separatorów gazu, gazociągi terenowe, tłocznie) w celu określenia parametrów technologicznych z wykorzystaniem równania stanu Clapeyrona–Mendelejewa dla gazów rzeczywistych. Wyniki wykazują duże błędy. Dowodzi to po raz kolejny, że wielu autorów opracowało równania stanu dla gazów rzeczywistych na podstawie wyników badań laboratoryjnych z gazami jednoatomowymi i laboratoryjnymi (wodór, azot, tlen, dwutlenek węgla itp.). Natomiast obecnie autorzy przeprowadzili badania laboratoryjne z udziałem eksploatowanych węglowodorów i towarzyszącego im gazu ropopochodnego. Na podstawie wyników badań laboratoryjnych autorzy zalecili korektę równania stanu dla gazu ziemnego i towarzyszących mu gazów ropopochodnych.

11

Manufacture of Clay Aggregate Doped with Pozzolan Destined for Lightweight Concrete

Mesrar Hamza, Mesrar Laila, Touache Abdelhamid, Jabrane Raouf

Journal of Ecological Engineering

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2023

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Vol. 24, nr 1

349--359

EN

In this work, marl clay was used because these materials have a very important industrial potentiality in several fields, namely ceramics. The objective was manufacturing expanded clay aggregate (ECA), with two main ingredients of marl and pozzolan at different percentages in order to integrate them into the concrete as aggregate. The physicochemical parameters of the mixture marl / Pozzolan was discussed and the results of the analyses, allowed deducing that the sample with 15% pozzolan has the most expansion rate of 16.8%, and its density of 1232 kg/m3 is in accordance with the international standard of expanded aggregates. The density of the concrete decreases with the quantity of ECA added and reaches its minimum with 1671 kg/m3 according to concrete with 50% of the expanded aggregate. The bending tests show the increase of the mechanical strength as a function of the quantities of aggregate added. The results show a very important potential with the addition of clay aggregates, density and water absorption decrease with the increase of the mechanical resistance.

12

The impact of layout and concentration of defects on the electromechanical constraints in the MV cables insulation

Medoukali Hemza, Zegnini Boubakeur

Diagnostyka

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2023

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Vol. 24, No. 2

art. no. 2023206

EN

The problem of the dense presence of voids in the solid insulation of cables remains a concern for researchers in terms of diagnosis and maintenance. The focus of this paper is to investigate the influence of both the layout and density of microcavities on the electrical and electromechanical constraints in the XLPE insulation of MV cables using numerical simulation. The simulation is based on the resolution of Laplace’s equation by the finite element method (FEM) using MATLAB. The electrostatic pressure and the elongation of the microcavities are estimated. This elongation leads to the formation of microchannels and then develops due to partial discharges to arborescence and in the end, the cable becomes out of service. This process takes a long time, so we use simulations to deepen the understanding of this phenomenon in a very short time. The electromechanical constraints are determined for different layouts and densities of microcavities.

13

Effect of sintering temperature and isostatic pressure on selected properties of selected electrical contact materials manufactured by hot isostatic pressing

Kołacz Dariusz, Kulasa Joanna, Krukowski Karol, Hury Anna, Muzia Grzegorz, Osadnik Małgorzata, Kalabis Jarosław

Composites Theory and Practice

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2023

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R. 23, nr 2

67--75

EN

This paper presents the results of studies on the consolidation of metallic and composite powders by the hot isostaticpressing (HIP) process intended for electrical contact materials. Ag, Cu metallic powders, as well as AgW48Re2, AgRe1 and CuW47Re3 composite powders were used in the investigations. Green compacts for consolidation and hot sintering under pressure were prepared by double-sided axial pressing in steel dies. The density, electrical conductivity, and hardness were measured on the obtained sinters after the HIP process, and the microstructure was examined on selected ones. The research indicates that applying this technology allows good quality electrical material to be obtained, intended for electrical contact material.

14

Analytical versus experimental investigation of physical and mechanical characteristics of stir cast hybrid aluminium nanocomposite

Kumar Dinesh, Singh Satnam, Angra Surjit

Composites Theory and Practice

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2023

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R. 23, nr 3

136--144

EN

Aluminium alloys have good mechanical and physical properties and are lightweight, easy to cast, and simple to machine. Aluminium alloys are widely used in the aviation industry, auto sector, defence sector, and structural industries because of their promising abilities. The fundamental aim of this study was to investigate the mechanical properties and physical characteristics of a stir cast hybrid aluminium nanocomposite reinforced with 1-3 wt.% cerium oxide (CeO2) and graphene nanoplatelets (GNPs). Utilizing SEM, microstructural analysis was carried out. The existence of the elements of the reinforcement in the manufactured nanocomposite specimens was verified using EDAX. With an increase in the reinforcement wt.%, improvements in the mechanical and physical properties were seen. In the hybrid nanocomposites reinforced with 3 wt.% GNPs and 3 wt.% CeO2, a low porosity of 1.06% was observed. The best results for tensile strength, yield strength, and microhardness were 398 MPa, 247 MPa, and 119.6 HV, respectively. The SEM micrographs of the studied materials showed that the reinforcement particles were uniformly dispersed and refined into ultrafine grains.

15

Evaluation of the antiwear properties of timely changed engine oils

Skonieczna Daria, Vrublevskyi Oleksandr, Szczyglak Piotr

Combustion Engines

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2023

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R. 62, nr 4

116--122

EN

The article presents the results of tests, replaced according to the vehicle manufacturer's recommendations, of engine oils. The sample of engine oils in service came from spark-ignition and compression-ignition vehicles used in urban or mixed mode. During their collection, the type of drive unit, the mileage of the car and the number of kilometers the oil was used for were recorded for each sample (this was the main criterion for differentiating samples). In addition, a control group of samples consisting of fresh oils of the same viscosity grade and distributed by the same producer was set up to observe changes in the parameters of individual lubricants after the operating period. The first part of the empirical study consisted of determining the physico-chemical properties of the lubricants, i.e.: kinematic viscosity, density and water content. The second part involved anti-wear tests using a T-02U tribometer. The use of the tribometer made it possible to record the anti-wear parameter, i.e. moment of friction, and also the load imposed on the friction node, as a result of which it was possible to calculate the friction force and friction coefficient. The research was complemented by an analysis of worn surfaces of the friction node on a microscope. The tests carried out can be used for predictive purposes, in terms of assessing the condition of a lubricant subjected to an operating process in an internal combustion engine.

16

Analysis of Standard Methods for Determining the Properties of Explosive Materials in Ukraine

Zakusylo Roman, Zakusylo Daryna, Sałaciński Tomasz

Central European Journal of Energetic Materials

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2023

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Vol. 20, no. 1

75--91

EN

Standardized methods for determining the basic properties of energysaturated materials in Ukraine are considered. The optimal directions for the use and development of explosives testing methodology in Ukraine are presented. All of the methods considered can be applied under certain conditions, depending on the initial requirements for the test explosive.

17

Influence of Sintering Temperature on the Pore Structure of an Alkali-Activated Kaolin Based Geopolymer

Ramli Mohd Izrul Izwan, Salleh Mohd Arif Anuar Mohd, Aziz Ikmal Hakem, Zaimi Nur Syahirah Mohamad, Amli Siti Farahnabilah Muhd, Abdullah Mohd Mustafa Al Bakri

Archives of Metallurgy and Materials

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2023

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Vol. 68, iss. 3

987-989

EN

Kaolin-based geopolymers are alternatives for producing high-strength ceramics for construction materials. Creating high-performing kaolin ceramics utilizing the regular technique requires a high handling temperature (higher than 1200°C). Thus, the structure and properties such as pore size and distribution are affected at higher sintering temperatures. Along these lines, information with respect to the sintering system and related pore structure is essential for advancing the properties of the previously mentioned materials. This study investigated the microstructure and the density of a kaolin-based geopolymer at various sintering temperatures. The unsintered sample has the highest density of 1610 kg/cm3 , while the samples sintered at 1100°C haves the lowest density of 1203 kg/cm3 . The result also shows that increasing the sintering temperature to 1100°C resulted in increasing the water absorption of the kaolin-based geopolymer ceramic.

18

Densification and Magnetic Properties of Fe Powder Compacts According to Heat-Treatment Conditions

Yoo Hyo-Sang, Kim Yong-Ho, Kim Cheol-Woo, Son Hyeon-Taek

Archives of Metallurgy and Materials

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2023

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Vol. 68, iss. 1

47--50

EN

In this study, the effects of heat-treatment conditions of Fe powder compacts on densification, microstructure, strength and magnetic properties were investigated. The prepared Fe powder was compressed in a mold of diameter 20 mm at a pressure of 800 MPa for 30 sec. This Fe powder compact was heat-treated under different atmospheres (air and 90% Ar + 10% H2 and heat-treatment temperatures (300 and 700℃). The Fe powder compacts heat-treated in an Ar+H2 mixed gas atmosphere showed a denser microstructure and higher density than the Fe powder compacts heat-treated in an air atmosphere. Oxygen content in the heat-treatment conditions played a signiﬁcant role in the improvement of the densiﬁcation and magnetic properties.

19

Selective Laser Melting Process Parameter Optimization on Density and Corrosion Resistance of 17-4PH Stainless Steel

Sahadevan Priya, Pon Selvan Chithirai, Manjunath Patel G. C., Bhaumik Amiya

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 4

105--116

EN

The 17-4 PH Stainless Steel material is known for its higher strength and, therefore, extensively used to build structures for aerospace, automotive, biomedical, and energy applications. The parts must operate satisfactorily in different environmental conditions to widen the diverse application. The selective laser melting (SLM) technique build parts cost-effectively, ensuring near-net shape manufacturability. Laser power, scan speed, and hatch distance operating at different conditions were used to develop parts and optimize for higher density in printed parts. Laser power, scan speed, and hatch distance resulted in the percent contribution towards density equal to 73.74%, 24.48%, and 1.78%. The optimized conditions resulted in higher density and relative density equal to 7.76 g/cm3 and 99.48%. Printed parts' corrosion rate and wear loss showed more stability in NaCl corrosive medium even at 75°C than 1M of HCL corrosive medium. Less pitting corrosion was observed on the samples treated in NaCl solution at 25°C and 75°C at 72 Hrs than in HCL solution. Therefore, 17-4 PH SS parts are best suited even in marine applications.

20

Greener, greater and… safer? How COVID-19 pandemic verified New York’s planning strategies

Jasiński Artur, Oktawiec Wojciech

Teka Komisji Urbanistyki i Architektury Oddział PAN w Krakowie

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2022

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T. 50

109--129

EN

The COVID-19 pandemic has exposed a specific paradox of contemporary urban planning. Cities that since the dawn of civilization have been considered the safest and most attractive human habitats turn into traps in a pandemic. For example New York, the most densely populated city in the United States, became the world’s epicentre of the pandemic in April 2020. Since 1992, successive teams governing the city stimulated proecological planning strategies. From a neglected city, threatened with crime and plagued by terrorism, they turned it into a green metropolis, a symbol of a city of the 21st century. One of the most important planning and urban achievements was the successful revitalization of the post-industrial waterfront piers of Brooklyn and Queens. The rapid growth of bicycle transport stimulated by the planning authorities and supported by the construction of a network of bicycle routes along the main streets and coastal promenades should be noted as well. The aim of this study is to investigate the effects of the planning transformations in New York on the course of the COVID-19 pandemic, and to answer the question whether they made the city more resilient and safer.

PL

Pandemia COVID-19 obnażyła swoisty paradoks współczesnej urbanistyki. Miasta, które od zarania cywilizacji były uważane za najbardziej bezpieczne i atrakcyjne siedliska ludzkie, podczas pandemii zmieniły się w pułapki. Nowy Jork, najgęściej zaludnione miasto USA, w kwietniu 2020 roku stał się światowym epicentrum pandemii. Specyfika Nowego Jorku wynika m.in. z faktu, że począwszy od 1992 roku władze prowadziły w miarę spójną politykę przestrzenną, co przyczyniło się do całkowitej zmiany wizerunku tej metropolii. Z miasta zaniedbanego, zagrożonego przestępczością działania te uczyniły zieloną metropolię, symbol miasta XXI wieku. Jednym z najważniejszych osiągnięć planistycznych i urbanistycznych była udana rewitalizacja poprzemysłowych nadbrzeży Manhattanu i sąsiadujących z nim nadbrzeży dzielnic Brooklyn i Queens. Odnotować należy także stymulowany przez planistów szybki rozwój komunikacji rowerowej. Celem niniejszej pracy jest zbadanie, jakie skutki dla przebiegu pandemii COVID-19 miały rezultaty tych przekształceń planistycznych dokonanych w Nowym Jorku w ciągu ostatniego trzydziestolecia, a także odpowiedź na pytanie, czy dzięki nim miasto stało się bezpieczniejsze i bardziej odporne.