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1

Everyone is different, but does it matter? : the role of heterogeneity in empirically grounded agent-based models of alternative fuel vehicles diffusion

Jędrzejewski Arkadiusz, Kowalska-Pyzalska Anna, Pawłowski Jakub, Sznajd-Weron Katarzyna

Operations Research and Decisions

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2025

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Vol. 35, No. 1

45--80

EN

There is a large literature on agent-based models (ABMs) to study the diffusion of alternative fuel vehicles (AFVs). Potentially, ABMs could be used to design policies that effectively promote AFVs. Unfortunately, ABMs have several drawbacks related to their complexity – models that are too simple are unrealistic, and models that are too complicated are difficult to describe, verify, and validate. Here we investigate what level of complexity is needed. We focus on the issue of heterogeneity because it is one of the biggest advantages of ABMs, but also one of the main sources of complexity. We begin with a brief review of ABMs for AFV diffusion. We then generalize an empirically grounded ABM of AFVs to analyze the role of different types of heterogeneity related to individual characteristics and social network structure. We show that most of these heterogeneities do not affect the outcome of the model. To facilitate replication of our results, we describe the model and its calibration to empirical data in detail. We also provide a link to a public GitHub repository where the code files, empirical data, and scripts are uploaded to analyze the results.

2

The formation regularities of aerosols resulting from arc welding of main gas pipelines

Semchuk Jaroslav, Vasyliv Nataliia, Kryvenko Galyna M., Lialiuk-Viter Halyna, Hrytsuliak Halyna Myhaylovna, Kotsyubynsky Andrij, Voloshyn Yurii

Nafta-Gaz

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2025

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R. 81, nr 8

530--537

EN

The oil and gas industry is characterized by the presence and operation of various high-risk facilities, which contribute to occupational injuries and diseases, as well as environmental pollution. Among these, pipeline systems – particularly main gas pipelines – are prominent. The purpose of this research is to study the processes involved in the manual arc welding of main gas pipelines during construction and repair, which adversely affect human health and the environment. Gas pipeline welding during construction and repair is performed both in semi-enclosed spaces and in the open air. In both cases, manual arc welding is predominantly used due to its mobility and ease of implementation. The equipment required for arc welding is much cheaper and simpler than that used for laser, electron beam, or hybrid welding. These advantages have led to the widespread use of arc welding across various industries. However, manual arc welding has a considerable negative impact on human health and the environment due to the emissions of toxic substances in the form of welding aerosols. The regularities of aerosol formation during arc welding and the mechanisms of their distribution in the environment are examined, enabling the planning of welding operations in a way that reduces the risk of occupational diseases. Empirical correlations were obtained to determine the concentrations of harmful substances. It was shown that an aerosol cloud, dispersed by wind, spreads with particles diffusing in all directions, leading to a rapid decrease in concentration. It was found that during the welding of pipes under moderate wind conditions, aerosol smoke from a point source spreads in the air in a conical torch shape, expanding both vertically and horizontally. It is substantiated that the main physical process involved is diffusion combined with heat transfer due to convective airflows. Based on Sutton’s modified mathematical model, it was established that during the welding of above-ground pipelines under laminar wind conditions, aerosol smoke mixes with air solely through molecular diffusion, whereas during underground welding, aerosol dispersion is caused by the physical processes associated with the formation of a welding torch.

PL

Przemysł naftowy i gazowniczy cechuje się obecnością i eksploatacją różnych obiektów wysokiego ryzyka, co wiąże się z występowaniem urazów zawodowych i chorób, a także z zanieczyszczeniem środowiska. Wśród tych obiektów szczególnie istotne są systemy rurociągowe, zwłaszcza główne gazociągi. Celem niniejszych badań jest analiza procesów zachodzących podczas ręcznego spawania łukowego głównych gazociągów w trakcie ich budowy i napraw, które mają istotny wpływ na zdrowie ludzi i stan środowiska naturalnego. Spawanie gazociągów podczas budowy i napraw odbywa się zarówno w przestrzeniach półzamkniętych, jak i na wolnym powietrzu. W obu przypadkach stosuje się głównie ręczne spawanie łukowe ze względu na jego mobilność i łatwość zastosowania. Sprzęt niezbędny do spawania łukowego jest znacznie tańszy i prostszy niż ten wykorzystywany do spawania laserowego, wiązką elektronów czy metodami hybrydowymi. Te zalety sprawiają, że spawanie łukowe jest szeroko stosowane w różnych gałęziach przemysłu. Niemniej jednak, ręczne spawanie łukowe ma znaczący negatywny wpływ na zdrowie człowieka i środowisko ze względu na emisję substancji toksycznych w postaci aerozoli spawalniczych. W pracy omówiono prawidłowości tworzenia się aerozoli podczas spawania łukowego oraz mechanizmy ich rozprzestrzeniania się w środowisku, co pozwala na planowanie prac spawalniczych w sposób ograniczający ryzyko chorób zawodowych. Uzyskano empiryczne zależności umożliwiające określenie stężeń substancji szkodliwych. Wykazano, że chmura aerozolu rozpraszana przez wiatr rozprzestrzenia się z cząstkami dyfundującymi we wszystkich kierunkach, co prowadzi do szybkiego spadku stężeń. Stwierdzono, że podczas spawania rur w warunkach umiarkowanego wiatru, dym aerozolowy ze źródła punktowego rozprzestrzenia się w powietrzu w formie stożkowego strumienia, rozszerzającego się zarówno pionowo, jak i poziomo. Wykazano, że głównym procesem fizycznym jest dyfuzja połączona z przenoszeniem ciepła na skutek konwekcyjnych przepływów powietrza. Na podstawie zmodyfikowanego modelu matematycznego Suttona ustalono, że podczas spawania rurociągów naziemnych w warunkach wiatru laminarnego, dym aerozolowy miesza się z powietrzem wyłącznie poprzez dyfuzję cząsteczkową, natomiast w przypadku spawania podziemnego dyspersja aerozoli jest spowodowana procesami fizycznymi związanymi z formowaniem się łuku spawalniczego.

3

Analysis of the microstructure and microhardness of the Stellite 1-WCL steel joint produced by the Direct Energy Deposition method

Małysza Marcin, Żuczek Robert, Wieliczko Piotr, Zięba Łukasz

Mechanik

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2025

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R. 98, nr 12

32--35

EN

The study presents the results of investigations on the microstructure, chemical composition, and microhardness of the cobalt alloy Stellite 1 joined to WCL tool steel, produced by the Direct Energy Deposition (DED) method. Analyses were conducted using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). Based on EDS results from two layers, the nature of element diffusion was determined, and the joint zones were identified: the deposit, the transition zone, and the heat-affected zone (HAZ). A gradient distribution of elements was observed, indicating an extensive diffusion zone. Microhardness results confirmed the transition from the hard structure of the deposit to the softer substrate. It was found that the joint is characterized by structural continuity.

PL

W pracy przedstawiono wyniki badań mikrostruktury, składu chemicznego oraz mikrotwardości połączenia stopu kobaltu Stellite 1 ze stalą narzędziową WCL, wytworzonego metodą Direct Energy Deposition (DED). Analizy przeprowadzono z wykorzystaniem mikroskopii skaningowej (SEM) oraz mikroanalizy rentgenowskiej (EDS). Na podstawie wyników EDS z dwóch warstw określono charakter dyfuzji pierwiastków oraz zidentyfikowano strefy połączenia: napoinę, strefę przejściową i strefę wpływu ciepła (HAZ). Zarejestrowano gradientowy rozkład pierwiastków, wskazujący na rozległą strefę dyfuzyjną. Wyniki mikrotwardości potwierdziły przejście od twardej struktury napoiny do miększego podłoża. Stwierdzono, że połączenie charakteryzuje się ciągłością strukturalną.

4

Badania szczelności połączeń sieci dystrybucyjnej w aspekcie wykorzystania wodoru.Część 1: Projekt stanowiska i wstępne wyniki

Kroczek Marcin, Kostowski Wojciech, Kulik Kinga

Gaz, Woda i Technika Sanitarna

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2025

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Nr 7-8

12-17

PL

Transport wodoru istniejącymi sieciami dystrybucji gazu ziemnego wiąże się z ryzykiem nieszczelności przez dotychczas szczelne elementy sieci. W artykule przedstawiono projekt dwóch stanowisk badawczych, do badania procesu dyfuzji wodoru przez wybrane elementy sieci, zwłaszcza różnego rodzaju połączenia rozłączne, w warunkach zbliżonych do rzeczywistych. Przedstawiono testowe wyniki badań oraz stwierdzono, że stanowisko II generacji jest gotowe do kontynuacji badań dla szerszego zakresu obiektów i parametrów.

EN

Transporting hydrogen through existing natural gas distribution networks involves the risk of leaks through previously leak-proof network components. The article presents a design for two test rigs for studying the process of hydrogen diffusion through selected network components, especially various types of pipeline connections, under near-real conditions. The first test results are presented and it is concluded that the second-generation test station is ready to continue testing for a wider range of objects and parameters.

5

Influence of Process Parameters on the Microstructural and Mechanical Characteristics of TLP Bonded IN718

Tarai Uttam K., Dwibedi Swagat, Biswal Deepak Ranjan, Biswal Alok R., Behera Madhab, Jhavar Suyog

Archives of Metallurgy and Materials

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2025

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Vol. 70, iss. 2

973--981

EN

Inconel 718 (IN718) superalloy is joined through transient liquid phase bonding using a interlayer material (BNi-2). This study explores the role of process parameters in joining IN718 with the TLP bonding process is explored. Microstructure evolution and mechanical performance of the bond are investigated using scanning electron microscopy, tensile test, and micro-hardness test. The bond metallurgy showed three distinct zones: the base material zone, the diffusion-affected zone containing a large number of boride precipitates, and the isothermal solidification zone. Further investigation reveals that the ISZ contains a few brittle intermetallic particles, which reduce the mechanical properties of the bond. The results demonstrates that higher bonding temperature, time, optimal interlayer thickness, and pressure enhance the mechanical and microstructural properties of the bond. The bond formed at 1423 K bonding temperature, 1.5 h holding time, 80 μm interlayer thickness, and 12.5 kg load demonstrates the highest strength of 625 MPa.

6

Analysis of Tribological Wear of Metallic Membranes After the Hydrogenation Process

Rutkowska-Gorczyca Małgorzata, Winnicki Marcin, Kowalewski Piotr

Tribologia

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2024

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nr 2

95--104

EN

The paper presents the results of tribological tests of copper material subjected to the cyclic hydrogenation process. Tribological tests during friction in reciprocating motion, in contact with a ceramic ball. The measurement was performed for different numbers of hydrogenation cycles, different surface roughness and different times after the machining process. The test material consisted of metallic membranes made of dendritic copper particles using the additive method of low-pressure cold gas spraying (LPCS). The hydrogen charging process was carried out using a BioLogis SP50ze potentiostat/galvanostat. The current waveforms were carried out in an electrolyte with a concentration of 0.5 M H2SO4 . Voltammetry (CV measurement) was performed in a three-electrode system, where the metallic membrane was the working electrode. The hydrogen charging process included two ranges: 25 cycles (1 hour) and 50 cycles (2 hours). The system was cyclically loaded with current between a potential of -0.200 V and -1.4 V, with a scanning rate of 20 mV/s. The tests carried out allowed for obtaining the values of the friction coefficient and the wear depth. For materials with a developed surface (high roughness), a decrease in the value of the friction coefficient and the depth of the wear trace was observed with an increase in the number of hydrogenation cycles. This indicates an increase in the amount of hydrogen in the rubbing surface by expanding the surface. In the case of polished samples, the best results were obtained with 25 hydrogenation cycles.

PL

W pracy przedstawiono wyniki badań tribologicznych materiału miedzianego poddanego procesowi cyklicznego nawodorowywania. Badania tribologiczne podczas tarcia w ruchu posuwisto-zwrotnym w styku z kulką ceramiczną wykonano dla różnych ilości cykli nawodorowywania, różnej chropowatości powierzchni i w różnym czasie od procesu obróbkowego. Materiał do badań stanowiły membrany metaliczne wykonane z dendrytycznych cząstek miedzi metodą przyrostową niskociśnieniowego natrysku zimnym gazem (LPCS). Proces ładowania wodorem przeprowadzono z zastosowaniem potencjostatu/galwanostatu BioLogis SP50ze. Przebiegi prądowe prowadzono w elektrolicie o stężeniu 0,5 M H2SO4. Woltamperometrię (pomiar CV) przeprowadzono w układzie trójelektrodowym, gdzie membrana metaliczna stanowiła elektrodę roboczą. Proces ładowania wodorem obejmował dwa zakresy 25 cykle (1 h) oraz 50 cykli (2 h). Układ był cyklicznie prądowo obciążany między potencjałem o wartości -0,200 V a -1,4 V, z szybkością skanowania 20 mV/s. Przeprowadzone badania pozwoliły na uzyskanie wartości współczynnika tarcia oraz głębokości zużycia. Dla materiałów o rozwiniętej powierzchni (duża chropowatość) zauważono zmniejszanie wartości współczynnika tarcia oraz głębokości śladu zużycia wraz ze zwiększaniem ilości cykli nawodorowywania. Wskazuje to zwiększenie ilości wodoru w powierzchni trącej poprzez rozwinięcie powierzchni. W przypadku próbek wypolerowanych najlepsze wyniki uzyskano przy 25 cyklach nawodorowywania.

7

The “diffusion approximation” approach for describing the oil field development process

Mammadov Aziz V., Sultanova Arzu V., Mammadov Ramil M.

Nafta-Gaz

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2024

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R. 80, nr 5

293--300

EN

Analysis of the interaction of wells in the process of oil field development is based in particular on calculating the correlation coefficient of two adjacent wells. However, due to reservoir heterogeneity, this approach fails to consider the possibility of interactions between wells located at significantly greater distances. The non-equilibrium of the system is attributed to its openness, associated with environmental impacts (flooding process and changes in the stock of existing wells). The oil field development is a complex process, subject to complex works such as well grid compaction, carrying out a wide range of geological and technical operations, etc. From this point of view, the development and exploitation of fields needs a “volumetric” approach, i.e. a diffusion approximation. A crucial aspect of oil production is the timely regulation of both current production rates and water impact on the reservoir system. The oscillatory nature of the time series of measurements of oil, water, and liquid production rates carries information about the state and behavior of the reservoir system. Analysis of the features of oscillatory processes of the technological indicators of well operation across the entire area of the deposit as a whole enables early diagnosis of changes in the state of the system. The approach of the production well stock analysis in terms of the amplitude-frequency characteristics of the dynamics of oil, water, “mobile” water, and flooding, as well as the specific ratios of produced oil to the volume of water injected into the reservoir (an indicator of the effectiveness of water stimulation) allows us to consider the development as a diffusion-like process.

PL

Analiza wzajemnego oddziaływania odwiertów na etapie zagospodarowania złóż ropy naftowej opiera się w szczególności na obliczaniu współczynnika korelacji dwóch sąsiadujących ze sobą odwiertów. Jednak ze względu na niejednorodność złoża, podejście to nie uwzględnia możliwości wzajemnego oddziaływania odwiertów położonych w znacznie większych odległościach od siebie. Brak równowagi systemu wynika z jego drożności, związanej z czynnikami środowiskowymi (proces nawadniania złoża i zmiany w stanie zasobów istniejących odwiertów). Zagospodarowanie złóż ropy naftowej jest złożonym procesem, podlegającym skomplikowanym pracom, takim jak zagęszczanie siatki odwiertów, przeprowadzanie szerokiego zakresu zabiegów geologicznych i technicznych, itp. Z tego punktu widzenia zagospodarowanie i eksploatacja złóż wymagają zastosowania podejścia „wolumetrycznego”, tj. aproksymacji dyfuzyjnej. Kluczowym aspektem procesu eksploatacji ropy naftowej jest terminowa regulacja zarówno bieżącego tempa eksploatacji, jak i wpływu wody na system złożowy. Oscylacyjny charakter serii czasowych pomiarów tempa wydobycia ropy, wody i innych mediów dostarcza informacji o stanie i zachowaniu systemu złożowego. Analiza cech procesów oscylacyjnych wskaźników technologicznych funkcjonowania odwiertów na całym obszarze złoża jako całości umożliwia wczesne diagnozowanie zmian w stanie systemu. Zastosowanie analizy zasobów odwiertu wydobywczego pod względem charakterystyki amplitudowo-częstotliwościowej dynamiki ropy naftowej, wody, wody „mobilnej” i nawadniania złoża, a także określonych proporcji wydobytej ropy naftowej względem objętości wody zatłoczonej do złoża (wskaźnik skuteczności stymulacji odwiertu poprzez wtłaczanie wody) pozwala traktować zagospodarowanie złoża jako proces dyfuzyjny.

8

Investigation of Methane-Hydrogen Mixtures in Vertical Pipelines

Marius Darie, Vlasin Nicolae, Prodan Maria, Burian Sorin, Pupazan Gabriela, Moldovan Lucian

Inżynieria Mineralna

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2024

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Vol. 1, no. 1

63--69

EN

The paper presents an assessment of issues regarding the separation phenomena of methane-hydrogen mixtures in vertical pipelines. In the first part of the paper, the explosion risk is underlined. Thus, the widespread use of methane in both the industrial and domestic sectors is well known. In practice, due to recent trends, the injection of hydrogen into dedicated methane installations, the differences in densities can lead to separation phenomena which have an unfavorable effect on the operating regimes of equipment using this mixture and also, on the risk of explosion. The use of hydrogen in the industry is not new, but the increasing impact in terms of the number of users may involve a higher number of accidents due to the increased field of probability of hazardous situations in terms of explosions. The second part presents the used methods. The diffusion and gravitational separation are presented as phenomena having opposite effects. The used methods are theoretical and simulation approaches. The theoretical model is based on a nondynamic model. Therefore, no time parameter was not involved in the model. A linear dependence with the height of the concentration variation was observed for the range of heights considered. The conducted simulation underlined the same conclusion regarding the magnitude of gravitational separations in the methanehydrogen mixtures. The main conclusion of the approach is that the separation phenomenon effect due to the gas density differences is negligible. The approach also revealed, as expected that the higher level of pipe is exposed to a higher risk of increased hydrogen concentration.

9

Badanie właściwości dyfuzyjnych biopolimeru alginianowego

Kwiatkowska-Marks Sylwia

Inżynieria Materiałowa

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2024

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Vol. 45, nr 6

5--33

PL

Właściwości dyfuzyjne biopolimeru, jakim był alginian wapnia, oceniono poprzez wielkość efektywnego współczynnika dyfuzji (De) wybranych jonów metali ciężkich w granulkach alginianowych. Granulki zawierały 5–10,8% mas. biosorbentu. Zbadano wpływ rodzaju jonu metalu, temperatury procesu, pH roztworu oraz zawartości alginianu w granulkach. Wartość De dla wybranych jonów metali ciężkich malała w kolejności: Cu > Zn > Pb > Cd > Cr. Dyfuzja jonów Cu(II) wewnątrz granulek alginianu wapnia przebiegała tym lepiej, im bardziej kwaśny był odczyn roztworu oraz im wyższa była temperatura procesu, a wzrost zawartości alginianu w granulkach prowadził do obniżenia wielkości De. Uzyskano dobrą zgodność danych doświadczalnych z modelem matematycznym.

EN

The diffusion properties of calcium alginate biopolymer was investigated by determining the effective diffusion coefficient (De) in alginate granules containing 5–10.8% by mass of biosorbent. The influence of the type of sorbed metal ion, process temperature, solution pH and alginate content in the granules was investigated. It turned out that diffusion proceeds better, the more acidic the solution pH and the higher the process temperature. Increasing alginate content in the granules led to a decrease in the De value. For selected heavy metal ions De value decreases in the following order: Cu > Zn > Pb > Cd > Cr. Good agreement of the experimental data with the mathematical model was obtained.

10

Tribological Behaviors of Oxynitride Coating on TC4 Alloy Prepared by Double Glow Technology

Yang Zhengang, Liang Wenping, Hu Linquan, He Wang

Archives of Metallurgy and Materials

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2024

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Vol. 69, iss. 3

851--858

EN

The oxynitride coating was fabricated on the surface of Ti6Al4V alloy via double glow plasma alloy technology to enhance the wear resistance. The protective coating is dense and homogeneous and has a multilayer structure (outermost oxygen-rich layer, middle nitrogen-rich layer, innermost nitrogen diffusion layer). The acoustic emission curve suggests that the critical load is 53.1 N, the bonding strength between oxynitride coating and substrate is adequate to the application due to the diffusion layer. The oxynitride coating has a maximum hardness about 1020 HV, which is significant harder than Ti6Al4V alloy (370 HV). Tribological behaviors of oxynitride coating were investigated at three loads. The results indicated that the friction coefficient of oxynitride coating is lower than that of substrate at the same conditions. The wear mechanism of oxynitride coating is mainly fatigue wear, which converts to adhesive wear and fatigue wear with increasing load. The protective layer can decrease the actual contact areas obviously during the wear tests, which attributed to the higher hardness and stability of oxynitride layer.

11

Effects of Main Alloying Elements on Interface Reaction between Tool Steel and Molten Aluminum

Yoon Young-Ok, Kim Nam-Seok, Ha Seong-Ho, Kim Bong-Hwan, Lim Hyun-Kyu, Kim Shae K.

Archives of Metallurgy and Materials

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2024

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Vol. 69, iss. 2

489--492

EN

Effects of Si and Mg as main elements on interface reaction between tool steel and molten Al alloy at 700°C were investigated. Pure aluminum and Al-10mass%Mg alloy showed relatively simple interfacial layers, whereas thicker, multi-layered reaction bonds were found in the diffusion couple of A380 alloy. The diffusion of a large amount of Fe into Al matrix throughout the interfacial layer led to the formation of Al-Fe based intermetallic particles in the Al base metals. The diffusion couple of Al-10mass%Mg alloy showed a similar intermetallic layer as that of pure Al, indicating that 10mass%Mg in the Al melt rarely affected the formation of Al-Fe intermetallic layers. However, A380 alloy showed much expanded soldering area and increased thickness of intermetallic layers. Based on the phase diagram calculated, the solubility of Fe in liquid Al increased significantly with increasing Si content up to apploximately 5mass%, while, in the case of 10mass%Mg addition, the Fe solubility gradually decreased with increasing Mg content. Al-10mass%Mg alloy also showed the same tendency as that of pure Al in the formation and distribution of intermetallic compounds. However, in the Al-12mass%Si alloy, two types of Al-Fe-Si ternary compounds are present on the Al-rich side.

12

Memory dependent triple-phase-lag thermo-elasticity in thermo-diffusive medium

Yadav Anand Kumar, Singh Aarti, Jurczak Paweł

International Journal of Applied Mechanics and Engineering

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2023

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Vol. 28, no. 4

137--162

EN

The objective of the paper is to look at the propagation and reflection of plane waves in a thermo-diffusion isotropic medium. The reflection of plane waves in a thermo-diffusion medium was investigated in this study with reference to triple phase lag thermo-elasticity. The memory dependent derivative (MDD) is applied for this investigation. The fundamental equations are framed and solved for a particular plane. The four plane waves that are propagating across the medium are, shown namely: longitudinal displacement, P-wave, thermal diffusion T-wave, mass diffusion MD-wave and shear vertical SV-wave. These four plane wave velocities are listed for a specific medium, illustrating the impact of the diffusion coefficient and are graphically represented. Expressions for the reflection coefficient for the incidence plane wave are produced from research on the reflection of plane waves from the stress-free surface. It should be noted that these ratios are graphically represented and shown when diffusion and memory dependent derivative (MDD) factors are in play. The new model is relevant to many different fields, including semiconductors, earth- engineering, and electronics, among others, where thermo-diffusion elasticity is significant. Diffusion is a technique that can be applied to the production of integrated circuits, MOS transistors, doped polysilicon gates for the base and emitter in transistors, as well as for efficient oil extraction from oil reserves. Wave propagation in a thermos-diffusion elastic media provides crucial information about the presence of fresh and enhanced waves in a variety of technical and geophysical contexts. For experimental seismologists, developers of new materials, and researchers, this model might be useful in revising earthquake estimates.

13

The River System Pollutant Migration in the Context of the Sudden One-Time Discharge with Consideration of the Bottom Sediments Influence (Case of Benzene Migration in the Stryi River, Ukraine)

Kuzyk Andriy, Karabyn Vasyl, Shuryhin Vladyslav, Sushko Yulia, Stepova Kateryna, Karabyn Oksana

Ecological Engineering & Environmental Technology

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2023

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Vol. 24, iss. 1

46--54

EN

Basing on the mathematical model developed with the account of influence of bottom sediments, the parameters of benzene migration in the river caused by one-time discharge into the Stryi River were investigated. The mathematical model of migration consists of two equations that describe the movement of pollutants in the river system, taking into account the flow rate, diffusion, sorption and desorption of the pollutant by the bottom sediments of the river. The parameters of benzene distribution in the "water-bottom sediments" system were experimentally determined under laboratory conditions. With the help of computer modeling, the temporal and spatial distributions of benzene in water and bottom sediments were obtained. The regularities of benzene concentration change depending on the composition of the bottom sediments of the river have been established. The dependencies can be extrapolated to other river systems and pollutants.

14

Prediction of Benzene Migration Parameters Resulting from Continuous Flow in a Mountain River

Shuryhin Vladyslav, Karabyn Vasyl, Kuzyk Andriy

Ecological Engineering & Environmental Technology

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2023

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Vol. 24, iss. 8

73--81

EN

Using a mathematical model that includes the influence of bottom sediments, a comprehensive study of the migration of benzene (C6H6) as a result of its continuous release into a mountain river was conducted. The adopted migration model consists of two equations that accurately describe the movement of pollutants within the river system, considering crucial factors such as flow velocity, diffusion, sorption, and desorption by river sediments. Through meticulous laboratory experiments, the distribution parameters that govern the behavior of benzene (C6H6) within the water-sediment system were successfulully determined. Leveraging advanced computer modeling techniques, intricate spatiotemporal profiles illustrating benzene (C6H6) concentrations in both water and sediments were generated. Furthermore, consistent patterns in the fluctuations of benzene (C6H6) concentrations that exhibit strong correlation with the specific composition of river sediments were identified. Importantly, these foundational relationships can be extrapolated to diverse river systems and various categories of pollutants.

15

Investigations of mass transfer in simulated biomedical systems

Adach-Maciejewska Anna, Kopka Klaudia

Chemical and Process Engineering : New Frontiers

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2023

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Vol. 44, nr 4

art. no. e46

EN

The work motivation was to investigate in vitro system simulating drug release from Drug Eluting Stent (DES). The experiments were conducted in a custom designed unit simulating drug release from polymer covering DES in a simplified way. The active substance diffuses from a thin, internal annular layer of hydrogel (imitating “stent”) to the outer cylindrical layer of hydrogel (“artery wall”) and is at once drifted away by coaxially flowing solution (“blood”). The conducted research proved functionality of the experimental unit. The rate of mass transfer depends considerably on the mass driving force and on the affinity of substance-hydrogel. The volumetric flow rate and liquid viscosity did not affect the process significantly. The effective diffusion coefficient was calculated as a process parameter and then used in the other variants. Diffusion in hydrogel is the mechanism limiting the mass transfer in the examined system. For the first attempt, the diffusive model used in literature was employed. The provided calculations are consistent with experimental data and therefore show that despite its simplifications the model allows to estimate the amount of released substance. In conclusion, the relative substance mass, changing over time, was estimated in the respective parts of the unit. The prospect of determining the relative mass of the substance appearing in the subsequent parts of the system over time provides the opportunity to adjust the respective process parameters, which will facilitate control over the rate of mass release.

16

Influence of diffusion on the reaction of sulfuric acid with ilmenites

Jabłoński Maciej, Lubkowski Krzysztof, Wróblewska Elwira

Chemical and Process Engineering : New Frontiers

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2023

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Vol. 44, nr 3

art. no. e23

EN

The reaction of ilmenite raw materials with sulfuric acid has been investigated to find out the influence of diffusion processes on the course of this reaction. Three different laboratory methods were used to initiate the reaction: mixing ilmenite with 83–85% sulfuric acid at a temperature of 80 ◦C, mixing ilmenite with 90% sulfuric acid at temperatures of 20–40 ◦C and adding water, and mixing ilmenite with water and adding 95% sulfuric acid. Changes of thermal power during the process (thermokinetics) were studied with the use of calorimetry. It was found that diffusion processes play an important role when the reaction is initiated by mixing ilmenite with water followed by the addition of sulfuric acid and are less important when the reaction is initiated by mixing ilmenite with concentrated sulfuric acid followed by the addition of water. To explain the influence of diffusion processes on the reaction, the model calculations based on mass and heat balance equations were involved. Model calculations showed that the diffusion and mass transport processes are so fast that the reaction kinetics is mainly influenced by the reaction on the surface of ilmenite particles. The adopted model of calculations showed a very good agreement with experimental results.

17

Interface Diffusion Behavior of Co40Al-X (X = Ni, Cr, Ti) System by Diffusion Multiple

Shang Hang, Gao Qiuzhi, Jiang Yujiao, Ma Qingshuang, Li Huijun, Zhang Hailian

Archives of Metallurgy and Materials

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2023

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Vol. 68, iss. 1

275--286

EN

Diffusion multiple method was applied to investigate the alloying elements distribution and interface diffusion reactions in Co-Al-X system, in order to accelerate the alloy development. The diffusion regions of Co-Al-X system at 1173 K were investigated by scanning electron microscope (SEM) and nanoindentation. SEM images show that phases of Co-Al-Ni diffusion interface consisted of β-CoAl + γ Co, γ Co, γ + γ'-(Co, Ni)3Al and γ Ni, while Co-Al-Cr diffusion interface is shaped with δ + γ + β, γ and σ region. TiNiX diffusion layer with high Ni-content was formed in Co-Al-Ti diffusion interface. The diffusion layers during diffusion multiple play an important role in mechanical properties in these alloying systems. The γ + γ' diffusion layer in Co-Al-Ni diffusion interface presented the best comprehensive performance, while the highest hardness (17.48 GPa) was confirmed in Co-Al-Cr diffusion interface due to a large number of brittle phases. Darken method was applied to determine the interdiffusion coefficients of alloying elements in pseudo-binary phase, accordingly the diffusion capacities of alloying elements can be ordered as Al > Ni > Cr in Co-based alloys.

18

Gas Nitriding of the Near-Beta-Titanium Alloy

Luk’yanenko Alexander G., Pohrelyuk Iryna M., Fedirko Viktor M., Molyar A. G., Trush Vasyl, Kravchyshyn T. M.

Archives of Metallurgy and Materials

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2023

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Vol. 68, iss. 2

431--438

EN

The present research investigates the nitriding kinetics of the near-beta-titanium alloy of Ti-Al-Nb-Fe-Zr-Mo-V system at 750, 800, and 850°C in gaseous nitrogen at 105 Pa for 2, 4, and 8 h. The parabolic coefficient kp of the layer’s growth rate and the nitriding activation energy E are set as the kinetic parameters of the nitrided layer’s growth. The activation energy for the formation of a nitride layer is ~108 kJ/mol. The authors discuss the morphology of the nitride layers as well as their roughness and surface hardness. The study determines the effective diffusion coefficient for the growth of diffusion layers in the temperature range of 750...850°C: Def = D0 × exp (-E/RT), where D0 = 0.0177 m2/s; E = 215.7 kJ/mol. The friction coefficient of the disk from nearbeta-titanium alloy with a bronze block is lowered by significantly more than 10 times after gas nitriding, and the temperature in the friction zone is reduced by 2.5 times.

19

Dynamical properties of a modified chaotic Colpitts oscillator with triangular wave non-linearity

Suresh Rasappan, Sathish Kumar Kumaravel, Regan Murugesan, Niranjan Kumar K. A., Narmada Devi R., Obaid Ahmed J.

Archives of Control Sciences

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2023

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Vol. 33, No. 1

25--53

EN

The purpose of this paper is to introduce a new chaotic oscillator. Although different chaotic systems have been formulated by earlier researchers, only a few chaotic systems exhibit chaotic behaviour. In this work, a new chaotic system with chaotic attractor is introduced for triangular wave non-linearity. It is worth noting that this striking phenomenon rarely occurs in respect of chaotic systems. The system proposed in this paper has been realized with numerical simulation. The results emanating from the numerical simulation indicate the feasibility of the proposed chaotic system. More over, chaos control, stability, diffusion and synchronization of such a system have been dealt with.

20

Use of solar energy in the technology of fruit drying

Korobka Serhiy, Boyarchuk Vitaliy, Syrotiuk Valerii, Syrotyuk Serhiy, Stukalets Igor, Golovko Volodymyr, Syrotyuk Hanna, Jakubowski Tomasz, Giełżecki Jan

Przegląd Elektrotechniczny

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2022

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R. 98, nr 6

37--44

EN

Companies in the agri-food industry of Ukraine are trying to rationally manage all forms of energy (including solar energy) needed to implement the production process. The study investigated the process of drying plant material (fruit) based on the use of solar energy (and the intensification of this process). The present process uses a combination of an air collector and a drying chamber. The measurable effect of the performed tests is the development of diagnostic techniques for heat transfer with alternative diffusion and moisture transfer potentials (the experiment was performed at the temperature of 25-60⁰C, drying time was 50-74 hours). The method is offered to calculate the diffusion and moisture transfer when drying the fruit in a solar dryer. The method enables the diagnosis of heat exchange processes and the analysis of the mathematical model of heat exchange processes [1]. The results of the research (analytical and experimental) indicate the possibility of intensifying the fruit drying process based on the solar dryer. The unit energy consumption during fruit drying in a solar dryer is reduced by 3-3.7 MJ/kg in relation to the currently used convection drying devices.

PL

Firmy z branży rolno-spożywczej Ukrainy starają się racjonalnie gospodarować wszystkimi formami energii (w tym energią słoneczną) potrzebną do realizacji procesu produkcyjnego. W pracy zbadano proces suszenia materiału roślinnego (owoców) w oparciu o wykorzystanie energii słonecznej (i intensyfikację tego procesu). Niniejszy proces wykorzystuje połączenie kolektora powietrznego i komory suszącej. Wymiernym efektem przeprowadzonych badań jest opracowanie technik diagnostycznych wymiany ciepła o alternatywnych potencjałach dyfuzji oraz przenoszenia wilgoci (doświadczenie przeprowadzono w temperaturze 25 ⁰C – 60 ⁰C, czas suszenia 50-74 godz.). Metoda oblicza dyfuzję i transfer wilgoci podczas suszenia owoców w suszarce słonecznej. Metoda umożliwia analizę procesów wymiany ciepła oraz modelu matematycznego procesów wymiany ciepła [1]. Wyniki badań (analitycznych i eksperymentalnych) wskazują na możliwość intensyfikacji procesu suszenia owoców w oparciu o suszarkę słoneczną. Jednostkowe zużycie energii podczas suszenia owoców w suszarni solarnej zmniejsza się o 3 MJ/kg - 3,7 MJ/kg w stosunku do obecnie stosowanych urządzeń do suszenia konwekcyjnego.