Terms Of Transport Research Articles

Solvability in the sense of sequences for some linear and nonlinear Fredholm operators with the logarithmic Laplacian

We study the solvability of certain linear and nonlinear nonhomogeneous equations in one dimension involving the logarithmic Laplacian and the transport term. In the linear case we show that the convergence in L 2 ( R ) of their right sides yields the existence and the convergence in L 2 ( R ) of the solutions. We generalize the results obtained in the earlier article of Efendiev and Vougalter [Solvability in the sense of sequences for some non-Fredholm operators with the logarithmic Laplacian. Monatsh Math. 2023] in the non-Fredholm case without the drift. In the nonlinear part of the work we demonstrate that, under the reasonable technical assumptions, the convergence in L 1 ( R ) of the integral kernels implies the existence and the convergence in L 2 ( R ) of the solutions.

Classification of cultivars of common peach (Persica vulgaris Mill.)

The existing classifications of peach cultivars are based on the morphological characteristics of vegetative and generative organs, and are of economic importance. The classification by N. I. Ryabov (1939) gained the greatest popularity. The entire cultural assortment of Persica vulgaris Mill. was divided by him into two varieties distinguished by the type of flower. A variety with a rose-shaped flower, P. vulgaris var. rosaeflora Rjab., is divided into 4 groups: 1. American early ripers; 2. Northern Chinese peaches of the ‘Chinese Cling’ type (with cartilage-like flesh texture); 3. cultivars of the Turkestan-Transcaucasian type; 4. South Chinese ‘Honey’ type peaches (honey peaches). A variety with a bell-shaped flower, P. vulgaris var. campanuliflora Rjab., is divided into two groups: 1. Iranian, the ‘Phillips Cling’ type (with cartilage-like flesh texture); 2. Iranian, the ‘Crawford’ type (with a fibrous flesh texture). The work was carried out in the collection orchard of the Research Institute of Plant Genetic Resources of Uzbekistan.Research has shown that the groups do not have a specific geographical area and consist of cultivars from all around the world. Peach cultivars are grouped according to a set of morphological characteristics, therefore, the average values of basic biological properties within a group are very close and the differences are insignificant, which complicates the use of the classification for scientific purposes.The proposed classification of peach cultivars is based on the botanical-geographical principle (Vavilov, 1935). It is proposed to divide all common peach cultivars into groups according to their geographical origin: 1. Chinese; 2. Transcaucasian; 3. European; 4. American; and 5. Central Asian. Each of these groups has its own distribution area. The biological properties of cultivars were formed under the influence of various soil and climatic conditions. Chinese peaches are frost and winter hardy and have a long dormancy period. However, in terms of commercial and taste qualities they are inferior to modern cultivars. They can be used in breeding for creating large-fruited, frostresistant, late flowering varieties. European cultivars were forming under different conditions and they should be used differentially; they are good source material for breeding cultivars with high commercial and taste qualities of fruits. Transcaucasian varieties are superior to other groups in terms of transportability. These are cultivars for canning and high quality processed products. They are relatively resistant to fungous diseases. American cultivars are distinguished by high commercial and taste qualities of fruits. Most cultivars are highly frost-resistant, but they are poorly winterhardy. They can be used for breeding highly productive cultivars with high commercial and taste qualities of fruits, with different ripening periods. Central Asian varieties have a long dormancy period, they are frost-, drought-, and soil salinity resistant. However, they are weakly resistant to fungous diseases. They can be used in breeding according to the indicated characteristics

Structural, morphological, optical, magnetic and impedance spectroscopic properties of Ni0·5Fe2·5O4 nanoparticles synthesized by the self-combustion method

The synthesis of Ni0·5Fe2·5O4 nanoparticles was successfully carried out by the self-combustion method using glycine as fuel. Analysis of the XRD measurements indicates the formation of a cubic spinel monophase with the space group (Fd-3m) and a nanometric crystallite size. According to the optical study, this sample shows strong absorption in the visible range with a gap energy of 3.7 eV, making it a good candidate for optoelectronic and photovoltaic applications. Complex impedance spectroscopy was carried out in the temperature range 300–480 K with the frequency varying between 40 Hz and 5 MHz. The frequency dependence of the dielectric constant was explained in terms of charge carrier transport between Fe2+ and Fe3+, while its temperature dependence indicates dielectric relaxor behavior. The scaling law shows a perfect superposition of impedance and modulus spectrum in the temperature range studied which confirms that the increase of temperature does not bring any change on the mechanism of relaxation. For the electrical properties, the conductivity study shows a semiconducting behavior with a predominance of the Non-Overlapping Small Polaron Tunneling (NSPT) model over the conduction process. The dc conductivity and jump frequency are positively correlated by the extracted activation energies. Summerfield scaling leads to the superposition of the conductance spectra into a single main curve, confirming the validity of this approach. The low value of the dielectric loss and the high value of the permittivity at room temperature and at low frequencies make this sample a potential candidate for energy storage and microwave devices. In addition, the dependence of the magnetisation on the applied magnetic field has been studied in depth by adjusting the hysteresis cycle by different laws of the saturation approach.

Enhancing Polymer Electrolyte Membrane Fuel Cells with Ionic Liquids: A Review.

Polymer electrolyte membrane fuel cells (PEMFCs) represent a promising clean energy solution. However, their widespread adoption faces hurdles related to component optimization. This review explores the pivotal role of ionic liquids (ILs) in enhancing PEMFC performance, focusing on their role in polymer electrolyte membranes, catalyst modification, and other components. By addressing key obstacles, including proton conductivity, catalyst stability, and fuel crossover, ILs provide a pathway towards the widespread commercialization of PEMFCs. In the realm of PEMFC membranes, ILs have shown great potential in improving proton conductivity, mechanical strength, and thermal stability. Additionally, the utilization of ILs as catalyst modifiers has shown promise in enhancing the electrocatalytic activity of electrodes by serving as an effective stabilizer to promote the dispersion of metal nanoparticles, and reduce their agglomeration, thereby augmenting catalytic performance. Furthermore, ILs can be tailored to optimize the catalyst-support interaction, ultimately enhancing the overall fuel cell efficiency. Their unique properties, such as high oxygen solubility and low volatility, offer advantages in terms of reducing mass transport and water management issues. This review not only underscores the promising advancements achieved thus far but also outlines the challenges that must be addressed to unlock the full potential of ILs in PEMFC technology, offering a valuable resource for researchers and engineers working toward the realization of efficient and durable PEMFCs.

Applications of regime-switching in the nonlinear double-diffusivity (D-D) model

The linear double-diffusivity (D-D) model of Aifantis, comprising two coupled Fick-type partial differential equations and a mass exchange term connecting the diffusivities, is a paradigm in modeling mass transport in inhomogeneous media, e.g., fissures or fractures. Uncoupling of these equations led to a higher order partial differential equation that reproduced the non-classical transport terms, analyzed independently through Barenblatt’s pseudoparabolic equation and the Cahn–Hilliard spinodal decomposition equation. In the present article, we study transport in a nonlinearly coupled D-D model and determine the regime-switching of the associated diffusive processes using a revised formulation of the celebrated Lux method that combines forward Fourier transform with a Laplace transform followed by an Inverse Fourier transform of the governing reaction–diffusion (R–D) equations. This new formulation has key application possibilities in a wide range of non-equilibrium biological and financial systems by approximating closed-form analytical solutions of nonlinear models.

Hydrogen assisted cracking using an efficient virtual element scheme

In this paper, a novel virtual element formulation is proposed for phase field modeling of hydrogen assisted cracking (HAC). The multiphysics variational framework is decoupled into three parts which can be solved in a staggered manner, namely, the mechanical, diffusion, and damage sub-problems. The damage and diffusion sub-problems are treated as reaction–diffusion types of equations. The former is subjected to irreversibility constraints while the latter incorporates a transport term to represent the effect of mechanical loading. An efficient super-convergent patch recovery (SPR) scheme is utilized to determine the coefficient of transport term in the hydrogen diffusion equation. Several qualitative and quantitative benchmark problems are considered to validate the proposed framework’s performance. The results show excellent agreement with the corresponding FEM and experimental studies. Meanwhile, without loss of numerical accuracy, the VEM outperforms the FEM with regards to CPU time & memory efficiency and exhibits remarkable versatility in the selection of different element types for simulation. Moreover, this work demonstrates the potential of facilitating the VEM to solve real-scale fracture mechanics problems with multi-physics coupling.

Terminological clarification of the concept of truck overload

The article analyzes the concept of overload in relation to freight vehicles in conditions of weight control of vehicles. Based on the results of the analysis of a number of publications in this area, including scientific ones, it is indicated that the term "overload" used in them is identified with exceeding the normatively established permissible mass and (or) loads on the axles of the vehicle, which, in the reasonable opinion of the author, is incorrect. Based on knowledge in the field of terminology theory and guided by existing dictionary definitions of overload in railway and maritime transport, it is proposed to give the term "overload" in truck transport a similar meaning. Keywords freight vehicles, weight control, standard road loads, overload, vehicle axle loads, transport terms

Juridical Analysis of Eradicating Illegal Narcotics at the Border of the Riau Islands Region (Research Study by the Directorate of Narcotics Research at the Riau Islands Regional Police)

Eradicating illegal narcotics on the borders of the Riau Islands region or maritime areas connected to sea routes has a high prospect for the spread of narcotics crimes across national borders. To tackle the criminal act of smuggling narcotics from abroad into Indonesia via the Riau Islands sea route, the Riau Islands Regional Police's narcotics research directorate is carrying out in-depth prevention efforts through evaluating cross-country narcotics trafficking routes or what are commonly known as rat routes in order to minimize and reduce the level of cross-border narcotics smuggling. in the Riau Islands region. The problem in this research is how to regulate the eradication of illicit narcotics at the borders of the Riau Islands region, what are the implementation, obstacles and solutions for optimizing the eradication of illicit narcotics at the borders of the Riau Islands region, and what are the monitoring efforts carried out in eradicating illicit narcotics at the borders of the Riau Islands region (Research Study at the Directorate Riau Islands Regional Police Narcotics Investigation). The results of the research show that the eradication of illicit narcotics at the borders of the Riau Islands region (research study of the Kepri Police's drug investigation directorate) has been running in accordance with the duties and functions of the detective unit, for the obstacles faced in terms of infrastructure and transportation so it is hoped that the field process will be further improved. running optimally.

A van der Waals p-n heterostructure of GaSe/SnS2: a high thermoelectric figure of merit and strong anisotropy.

In recent years, van der Waals heterostructures (vdWHs) with controllable and peculiar properties have attracted extensive attention in the fields of electronics, optoelectronics, spintronics and electrochemistry. However, vdWHs with good thermoelectric performance are few due to the complex coupling of thermoelectric coefficients. Here, we employ density functional theory and Boltzmann's transport equation to explore the thermoelectric properties of the p-n vdWH of GaSe/SnS2, which has been experimentally observed to exhibit high performance as an optoelectronic device. We reveal that GaSe/SnS2 possesses strong anisotropy in terms of electronic transport resulting from the anisotropic carrier relaxation time. The longer carrier relaxation time in the y-direction for n-type induces a high power factor of 0.084 W m-1 K-2 at 300 K, while it is only 0.0087 W m-1 K-2) in the x-direction. The strong coupling of low-mid frequency phonon branches and the relatively weak Sn-S bond-induced anharmonicity hinder the phonon transport, which results in the lattice thermal conductivity of GaSe/SnS2 (14.61 and 15.43 W m-1 K-1 along the x- and y-directions at 300 K) being much smaller than the average value of GaSe and SnS2 (43.44 W m-1 K-1 at 300 K). The optimal thermoelectric figure of merit at 700 K for GaSe/SnS2 reaches 2.99, which is significantly higher than those of the constituents of GaSe (0.58) and SnS2 (1.04). The present work highlights the potential thermoelectric applications and the understanding of the thermoelectric transport mechanism for the recently synthesized p-n vdWH of GaSe/SnS2 with a high thermoelectric figure of merit and strong anisotropy.

Insights into Bactericera cockerelli and Candidatus Liberibacter solanacearum interaction: a tissue-specific transcriptomic approach.

The tomato-potato psyllid, Bactericera cockerelli (Šulc), belonging to the Hemiptera order, is an insect pest of solanaceous crops and vectors a fastidious bacterium, Candidatus Liberibacter solanacearum (CLso), the presumptive causal agent of zebra chip and vein greening diseases in potatoes and tomatoes, respectively. The genome of B. cockerelli has been sequenced recently, providing new avenues to elucidate mechanistic insights into pathogenesis in vegetable crops. In this study, we performed RNA-sequencing of the critical psyllid organs (salivary glands and ovaries) involved in CLso pathology and transmission to host plants. Transcriptome analysis revealed differentially expressed genes and organ-specific enrichment of gene ontology (GO) terms related to metabolic processes, response to stress/stimulus, phagocytosis, proteolysis, endocytosis, and provided candidate genes encoding transcription factors (TFs). To examine gene regulatory networks across the psyllid organs under CLso(-) and CLso(+) conditions, we performed weighted gene co-expression network analysis (WGCNA), and unique modules differentiating the psyllid organs were identified. A comparative GO analysis of the unique gene modules revealed functional terms enriched in response to stress, gene regulation, and cell division processes in the ovaries. In contrast, respiration, transport, and neuronal transmission-related GO terms were enriched in the salivary glands. Altogether, this study reveals new insights into tissue-specific expression of the psyllid organs in the absence or presence of CLso bacterium. This knowledge can be leveraged to develop new pest and disease management strategies by delineating the regulatory networks involved in the psyllid-CLso interaction.

TRANSPORT POSSIBILITIES OF CENTRAL ASIAN COUNTRIES

At a time when the Silk Road is being restored and international trade is growing, the countries of Central Asia are opening up new opportunities in terms of transport and access to the sea. This region, which was historically at the heart of global trade and cultural exchange, is now poised to reclaim its position as a vital hub in the modern global transportation network. The article "Transport Possibilities of Central Asian Countries" explores the significant role that transportation infrastructure and logistics play in shaping the economic destiny of these nations.

A New Hybrid Mass‐Flux/High‐Order Turbulence Closure for Ocean Vertical Mixing

AbstractWhile various parameterizations of vertical turbulent fluxes at different levels of complexity have been proposed, each has its own limitations. For example, simple first‐order closure schemes such as the K‐Profile Parameterization (KPP) lack energetic constraints; two‐equation models like directly solve an equation for the turbulent kinetic energy but do not account for non‐diffusive fluxes, and high‐order closures that include the high‐order transport terms are computationally expensive. To address these, we extend the Assumed‐Distribution Higher‐Order Closure (ADC) framework originally proposed for the atmospheric boundary layer and apply it to the ocean surface boundary layer. By assuming a probability distribution function relationship between the vertical velocity and tracers, all second‐order and higher‐order moments are exactly constructed and turbulence closure is achieved in the ADC scheme. In addition, this ADC parameterization has full energetic constraints and includes non‐diffusive fluxes without the computational cost of a full higher‐order closure scheme. We have tested the ADC scheme against a combination of large eddy simulation (LES), KPP, and for surface buoyancy‐driven convective mixing and found that the ADC scheme is robust with different vertical resolutions and compares well to the LES results.

Subject matter of crime violation of the procedure for transplantation of human anatomical materials established by law

The article is devoted to highlighting the topical issues related to the subject matter of the crime violation of the procedure for transplantation of human anatomical materials established by law. Based on the analysis of Ukrainian legislation and scientific works of Ukrainian scientists, the author offers own vision of the issue related to the subject matter of the analysed crime, namely: the author considers the maximum permissible terms of transportation and optimal storage periods for such organs as heart, kidneys, liver, left and right lobes of the liver, lung, and homograft. In addition, the author considers the definition of “anatomical materials”, expresses an opinion on the concept of transplantation of human anatomical material and offers own vision on the subject matter of the analysed crime. The author proposes to: 1) to introduce to Part 1 of Article 143 of the Criminal Code of Ukraine a qualifying feature i.e., the prohibition to use human anatomical materials which are not healthy or unsuitable for transplantation with violation of the term of their use; 2) to restate paragraph 1 of Part 1 of Article 299 of the Criminal Code of Ukraine as follows: “Cruel treatment of animals belonging to vertebrates, including homeless animals, violation of animals transportation rules, if such actions resulted in bodily injury, mutilation or death of an animal, illegal removal of organs or tissues from live animals, that belong to the vertebrates, setting animals against each other, committed for hooligan or mercenary motives, as well as propaganda, public calls for actions that have signs of cruelty to animals, distribution of materials calling for such actions – …”. It is also advisable to include DNA and DNA fragments in the list of human anatomical material, and to approve a separate list of human cells allowed for extraction, namely DNA and DNA fragments, in the relevant order of the Ministry of Health of Ukraine. To include DNA and DNA fragments in the list of human anatomical material in the Law of Ukraine “On the Application of Transplantation of Human Anatomical Materials” dated 17 May 2018 No. 2427-VIII and to amend the subject matter of the crime in respect of DNA and DNA fragments.

Role of Ionic Liquids As Modifiers of Ru-Based Catalysts for Water Electrolysis

The generation of hydrogen through electrocatalytic water splitting has attracted tremendous attention in the past years [1,2]. Although water electrolysis has been already established in industrial settings, a large amount of research is still being carried out to further improve the catalytic efficiency and stability to exploit the full potential of this technology. One approach in this endeavor is the utilization of ionic liquids (ILs) as modifiers of electrocatalysts and electrode surfaces [3, 4]. The special physicochemical properties of the IL can affect and ideally improve the characteristics of the electrocatalyst, e.g., in terms of mass and electron transport [3]. Furthermore, the hydrophilic nature of certain ILs can in addition influence gas bubbles removal on the working electrode and improve the stability of the catalysts (e.g., Ru) by acting as a monomer-like binder [4].In this study, we compared the effect of four different ILs that are based on the same cation chain (1-butyl-3-(4-methylphenethyl)-1H-imidazol-3-ium) but different anions (-OAc, -NTf2, -Br, and -MeSO3) on Ru nanoparticles as catalysts for hydrogen and oxygen evolution reactions (HER and OER). To this end, carbon nanotubes were functionalized using different ILs and subsequently decorated with 1-2 nm Ru nanoparticles (Ru NPs) following an established organometallic approach [5]. We analyze how the catalytic activity/stability for HER, as well as OER, is influenced by the metal-ILs combination by established electrochemical methods utilizing a rotational disc electrode setup, with a particular focus on the different hydrophilic natures (depending on the anion) of the four ILs. To obtain a more comprehensive picture of how the different ILs affect Ru dissolution during the reaction, the IL/catalyst systems are additionally investigated by inductively coupled plasma-optical emission spectroscopy (ICP-OES) in a flow cell setup, as well as by electrochemical quartz crystal microbalance (EQCM) measurements.In this work, we discuss the use of ILs as modifiers for catalyst/electrode systems in water-splitting reactions, highlighting the importance of careful IL selection as well as the necessity for more future research in this field to fully explore the potential of IL/NPs-systems in electrochemistry.

Upwind reproducing kernel collocation method for convection-dominated problems

Because of the best approximation property, traditional Bubnov–Galerkin numerical methods have proven immensely successful in modeling self-adjoint problems, such as heat conduction, elasticity, and so on. However, a numerical instability arises in these (and central finite difference) methods for problems with strong convection. In this class of problems, the convective transport term can lead to large spurious oscillations but can be handled by the class of Petrov–Galerkin methods. In particular, the upwind-type schemes and their variational and subgrid descendants have been substantially developed over the years for an effective weak-form Galerkin solution that precludes these instabilities. Nevertheless, the scale of development of upwind methods for strong-form collocation is substantially smaller, where numerical oscillations are also observed when they are straightforwardly applied to convection-dominated problems without special treatment. To this end, this paper presents a new upwind collocation method. First, the connection between the upwind finite difference scheme and the gradient smoothing technique in meshfree methods is established. It is then shown that selecting the collocation points as meshfree nodal points is not optimal; selecting the collocation points according to the flow direction and Péclet number is then studied. The upwind effect is achieved without introducing artificial parameters and is trivial to generalize for multi-dimensional cases. Cross-wind diffusion is also not observed in the solution. An error analysis is presented, and the effectiveness of the proposed methodology is well demonstrated by the steady and unsteady numerical examples.

Schizosaccharomyces pombe as a fundamental model for research on mitochondrial gene expression: Progress, achievements and outlooks.

Schizosaccharomyces pombe (fission yeast) is an attractive model for mitochondrial research. The organism resembles human cells in terms of mitochondrial inheritance, mitochondrial transport, sugar metabolism, mitogenome structure and dependence of viability on the mitogenome (the petite-negative phenotype). Transcriptions of these genomes produce only a few polycistronic transcripts, which then undergo processing as per the tRNA punctuation model. In general, the machinery for mitochondrial gene expression is structurally and functionally conserved between fission yeast and humans. Furthermore, molecular research on S. pombe is supported by a considerable number of experimental techniques and database resources. Owing to these advantages, fission yeast has significantly contributed to biomedical and fundamental research. Here, we review the current state of knowledge regarding S. pombe mitochondrial gene expression, and emphasise the pertinence of fission yeast as both a model and tool, especially for studies on mitochondrial translation.

Economic issue of using artificial neural networks with radial-basis transmission functions for modeling efficiency of management processes

ObjectivesThe paper presents the possibility of using artificial neural networks (ANN) with radial-basis transmission function (RBF) for modeling of economic phenomena and processes.Material and methodsThe basic characteristics and parameters of an ANN with RBF are shown and the advantages of using this type of ANN for modeling economic phenomena and processes are emphasized. Using an ANN with RBF, together with official statistics for 2010-2017, the modeling of the influence caused by work efficiency indicators of the customs authorities of Ukraine on the indicators of economic security of Ukraine was carried out. These eighteen indicators of economic security of Ukraine, which comprehensively characterize the economic status of the country in terms of production, social, financial, food, transport, energy, and foreign economic security, were chosen as the most informative indicators.ResultsThe results of the study showed that Artificial neural networks with Radial-basis transmission function well describe the trend of changing state economic security indicators under the influence of changing performance indicators of customs authorities. This allows us to recommend this type of artificial neural networks for analysis, evaluation and forecasting of economic phenomena and processes.ConclusionsThe results obtained showed good analytical and prognostic properties of an ANN with RBF when modeling the impact of customs authorities' performance on the state's economic security indicators.

Solution-mixed PANI-coated Bi2Si2Te6 nanosheet-based composite film for flexible thermoelectric energy harvesting

This paper introduces a novel approach for flexible thermoelectric energy (TE) harvesting via the synthesis and characterization of polyaniline (PANI)-coated Bi2Si2Te6 nanosheet (NS) composite films. The study focuses on enhancing the TE performance of the Bi2Si2Te6 NSs by coating their surfaces with PANI via a solution-mixing method. Specifically, the process involves exfoliation of Bi2Si2Te6 into nanosheets, followed by coating with camphorsulfonic acid (CSA)-doped PANI. An investigation of the TE power factor of the PANI-coated Bi2Si2Te6 NS is then conducted by analyzing the influence of the PANI coating times, and the results are explained in terms of the charge-carrier transport. Thus, the PANI-coated Bi2Si2Te6 NS composite films obtained using two coating cycles are shown to exhibit a maximum power factor of (∼411 μW/m·K2 at 500 K). Further, the flexibility and bending stability of the composites are revealed by an evaluation of their mechanical properties. Moreover, the as-fabricated PANI-coated Bi2Si2Te6 NS composite films exhibit outstanding durability after 1000 bending cycles. The findings contribute to the advancement of flexible inorganic/organic hybrid TE materials and their practical applications.

Selection of tramcars for sustainable urban transportation by using the modified WASPAS approach based on Heronian operators

The wrong design of rail system vehicle fleets is one of the most critical problems in terms of urban transportation. Light rail system fleets in many large cities, including Istanbul, consist of various types and feature vehicles. It creates significant problems in integrating each rail system vehicle into the system. In addition, while it is necessary to keep an inventory of spare parts for each different type of vehicle, it requires different qualifications for professionals involved in processes such as maintenance and repair, leading to extra costs. In this context, the study's primary purpose is to determine the most suitable light rail vehicles for urban transportation systems and create vehicle fleets accordingly. In that regard, the study aims to provide a reliable and practical decision-making model that can be used as a roadmap for decision-makers when choosing tramcars to solve these problems. The present work proposes a hybrid procedure integrating the Best and Worst Method (BWM) and Power-Heronian Weighted Aggregated Sum Product Assessment (WASPAS'PH) approaches. The most critical implication of the work indicated that the acquisition cost per tramcar set (0.148) is still the most influential factor. The economic lifespan of tramcars (0.037), the number of seats in a vehicle set (0.041), and energy consumption (0.072) have followed the most significant criterion, respectively. Besides, it highlighted that the A14 Brand CR (0.7819) is the most appropriate option for well-structuring the urban light rail system fleet. An extensive validation test to check the suggested model's robustness confirmed the procedure's stability and consistency.

Ozonation using a stainless-steel membrane contactor: Gas-liquid mass transfer and pharmaceuticals removal from secondary-treated municipal wastewater

A tubular porous stainless steel membrane contactor was characterized in terms of ozone-water mass transport, as well as its application in removing 23 pharmaceuticals (PhACs) detected in the secondary-treated municipal wastewater, under continuous mode operation. The volumetric mass transfer coefficient (KLa) was evaluated based on liquid flow rate, gas flow rate, and ozone gas concentration. The KLa values were substantially improved with an increment in liquid flow rate (1.6 times from 30 to 70 dm3 h−1) and gas flow rate (3.6 times from 0.30 to 0.85 Ndm3 min−1) due to the improved mixing in the gas-liquid interface. For the lowest liquid flow rate (30 dm3 h−1), the water phase boundary layer (82%) exhibited the major ozone transfer resistance, but it became almost comparable with membrane resistance for the highest liquid flow rate (70 dm3 h−1). Additionally, the influence of the specific ozone dose (0.39, 0.53, and 0.69 g O3 g DOC−1) and ozone inlet gas concentration (CO3,g,in = 27, 80, and 134 g Nm−3) were investigated in the elimination of 23 PhACs found in secondary-treated municipal wastewater. An ozone dose of 0.69 g O3 g DOC−1 and residence time of 60 s resulted in the removal of 12 out of the 23 compounds over 80%, while 17 compounds were abated above 60%. The elimination of PhACs was strongly correlated with kinetic reaction constants values with ozone and hydroxyl radicals (kO3 and kHO•), leading to a characteristic elimination pattern for each group of contaminants. This study demonstrates the high potential of membrane contactors as an appealing alternative for ozone-driven wastewater treatment.