bluuebunny/crossref_metadata_2025 huggingface dataset:
Review of Electrorheological Fluids (ERFs) as Smart Material
Authors: Shahinpoor Mohsen
Published: January 2023

Chapter 9 reviews electrorheological fluids (ERFs) as smart materials. ERFs belong to a class of smart materials capable of changing from a liquid phase to a much more viscous liquid and then to an almost solid phase in the presence of an electric field. They are essentially colloidal suspensions of highly polarizable particles in a nonpolarizable solvent. The solid phase of an ERF typically has mechanical properties similar to a solid like a gel and can perform the phase change from liquid to thick liquid like honey and then solid or in reverse from a solid transform to a thick liquid and then a thin liquid in a matter of few milliseconds. The effect is called the “Winslow effect” after its discoverer Willis M. Winslow, who obtained a US patent on the effect in 1947 and published an article on it in 1949. Note that the change is not just a change in fluid viscosity but also the emerging solid-like properties and hence these fluids are now known as ERFs, rather than by the older term electro-viscous fluids (EVFs). The effect is better described as an electric field dependent shear yield stress such as what occurs in a Bingham plastic (a type of viscoelastic material like thick honey or wax), with a shear stress yield point dependent on the electric field strength. The ERF once in a yield shear mode behaves like a Newtonian fluid when there is no yield shear stress and stress is directly proportional to the shear rate γ.
Versatile fabrication of metal sulfide supraparticles by an in situ decomposition–assembly strategy
Authors: Wang Menglei , Jia Fulin , Gong Jianxiao , Xia Yunsheng
Published: January 2023

Herein, an in situ decomposition–assembly strategy for the versatile fabrication of metal sulfide SPs is developed. In addition to homogeneous Cu2S, CdS, and ZnS products, the proposed system can even be extended to fabricate hybrid Cu2S/Fe2O3 SPs.
Improved symmetric flipped nested array for mixed near‐field and far‐field non‐circular sources localization
Authors: Wang Yinsheng , Cui WeiJia , Ba Bin , Du Bo , Yang Youzhen
Published: January 2023

At present, there are few sparse arrays used in the mixed near‐field (NF) and far‐field (FF) localization based on non‐circular (NC) signals. Inspired by the symmetric flipped nested array (SFNA) used in the existing mixed NF and FF NC source, in order to further improve the parameter estimation accuracy of the mixed NF and FF NC signal, an improved symmetric flipped nested array (ISFNA) for mixed NF and FF NC sources localization was developed. First, the uniform subarrays in the SFNA are rearranged, elements are extracted from the uniform subarrays and rearranged into ISFNA. ISFNA is more sparse, the array aperture is larger, and the array degree of freedom (DOF) is higher; second, the formula of the maximum consecutive lags of ISFNA is given; third, a special fourth‐order cumulant is used to eliminate the range parameter and then use a one‐dimensional (1‐D) spectral peak search to obtain all Directions of Arrival (DOAs). By defining the range search, the range can be obtained by bringing in estimated DOAs. Finally, the superiority of the proposed array is proved by simulation.
Research on voltage regulation ability of four‐level nested clamp converter based on virtual space vector modulation
Authors: Hu Liangdeng , Xiao Fei , Xin Ziyue
Published: January 2023

The four‐level nested neutral point clamped (4L‐NNPC) converter is a new multi‐level converter with a simple topology, which is suitable for the medium‐voltage application. But it has voltage balancing problems under the low output frequency condition. A space virtual vector modulation (SVVM) algorithm is introduced in this paper, and the dwell time formulas are given. It uses the synthesis between vectors to optimize the dwell time of each level in the virtual vector, in order to balance the flying capacitor voltage in the carrier period. In order to explore the boundary of the voltage regulation ability of the 4L‐NNPC converter, this paper analyses the mechanism of the voltage fluctuation of the flying capacitors and derives the voltage fluctuation formulas. The voltage regulation ability is calculated in different sectors, and the influence of the modulation ratio and power factor is explored. Finally, the voltage regulation ability under the sudden load and the flying capacitor voltage deviating from the rated value were investigated through simulation and experiments, which verified the correctness of the proposed theory.
Fault ride‐through control based on voltage prioritization for grid‐forming converters
Authors: Dadjo Tavakoli Saman , Prieto‐Araujo Eduardo , Gomis‐Bellmunt Oriol , Galceran‐Arellano Samuel
Published: January 2023

This paper discusses that the existing grid codes on the fault ride‐through (FRT) operation have certain complications to be implemented in the grid‐forming (GFM) converters. In particular, they do not provide a clear guidelines on the suitable prioritization of the positive‐ and negative‐sequence currents needed for a desired voltage profile during FRT operation. To address this challenge, two FRT controls which are based on (i) voltage balancing priority, and (ii) voltage magnitude priority are investigated for GFM converters. The former gives priority to the elimination of negative‐sequence voltage, while the remaining converter's capacity is used to increase the positive‐sequence voltage. On the contrary, the latter prioritizes the increase of positive‐sequence voltage, while it tries to reduce negative‐sequence voltage by using the remaining converter's capacity. The dynamic performances of these two FRT controls are thoroughly discussed, and the simulation results show that depending on the desired voltage profile during fault, one of them can be implemented.
Corrigendum: ‘Adaptive dynamic surface control of a two‐axis gimbal system’
Authors: Fathi Mohammad , Bolandi Hossein
Published: January 2023

An adaptive Dynamic Surface Controller (DSC) is designed for a two‐axis gimbal system with actuator dynamics in the presence of parametric uncertainties in [1]. A Lyapunov stability analysis is used to guarantee the convergence of the tracking error to the origin and boundedness of all closed‐loop signals. The main objective of this corrigendum is to point out several errors that occurred throughout the paper, resulting in the inaccuracy of the used dynamic model and ineffectiveness of the proposed controller. It should be noted that taking into account the corrections stated in this corrigendum, the main result of the original paper is still valid.
To see or not to see a z ∼ 13 galaxy, that is the question
Authors: Kaasinen M. , van Marrewijk J. , Popping G. , Ginolfi M. , Di Mascolo L. , Mroczkowski T. , Concas A. , Di Cesare C. , Killi M. , Langan I.
Published: January 2023

Context. Determining when the first galaxies formed remains an outstanding goal of modern observational astronomy. Theory and current stellar population models imply that the first galaxies formed at least at z = 14 − 15. But to date, only one galaxy at z > 13 (GS-z13-0) has been spectroscopically confirmed.

Aims. The galaxy ‘HD1’ was recently proposed to be a z ∼ 13.27 galaxy based on its potential Lyman break and tentative [O III] 88 μm detection with ALMA. We hereby aim to test this scenario with new ALMA Band 4 observations of what would be the [C II] 158 μm emission if HD1 is at z ∼ 13.27.

Methods. We carefully analyse the new ALMA Band 4 observations and re-analyse the existing ALMA Band 6 data on the source to determine the proposed redshift.

Results. We find a tentative 4σ feature in the Band 4 data that is spatially offset by 1.​​″7 and spectrally offset by 190 km s−1 from the previously reported 3.8σ ‘[O III] 88 μm’ feature. Through various statistical tests, we demonstrate that these tentative features are fully consistent with both being random noise features.

Conclusions. We conclude that we are more likely to be recovering noise features than both [O III] 88 μm and [C II] 158 μm emission from a source at z ∼ 13.27. Although we find no credible evidence of a z ∼ 13.27 galaxy, we cannot entirely rule out this scenario. Non-detections are also possible for a z ∼ 13 source with a low interstellar gas-phase metallicity or ionisation parameter and/or high gas density. Moreover, the new continuum and line upper limits provide no strong evidence for or against a lower-redshift scenario. Determining where and exactly what type of galaxy HD1 is, will now likely require JWST/NIRSpec spectroscopy.
Modeling the dynamics of speech behavior in the pragmatics of the language
Authors: Matveeva Galina , Shuraeva Fotina , Nesterova Anastasiya , Myasischeva Marina
Published: January 2023

The research is devoted to the study of the author's behavior in the texts of personal correspondence. The research is based on the material of letters of writers of the early twentieth century. The subject of the study was a corpus of texts by six writers. Collectively, the study of (linguistic-rhetorical) works. The analysis was carried out from the position of studying the author's strategy of influencing the reader in order to study the formation of a certain attitude. The use of pragmalinguistic methods of studying the speaker's speech portrait in the context of diachronic personality development allows us to identify personal speech preferences that characterize the speaker and determine the dynamics of his personality development based on his speech preferences. The conducted experiments show the possibility of speech diagnostics of the speaker's personality and reconstruct his speech portrait based on the materials of the monuments of writing.
Identification and Development of the Organisation Risk-Forming Factors Register
Authors: Kvitkina Marina , Pushenko Sergey , Staseva Elena
Published: January 2023

Official statistics show that labor activity is accompanied by the presence of various kinds of hazards and harmful working conditions, which are risk factors for injury and the development of occupational diseases of workers. Risk assessment is one of the necessary procedures of the occupational health and safety management system and includes the following stages: identification of all risk-forming factors characteristic of the organisation, compilation of a unified register of hazards, calculation of occupational risks and development of measures to reduce their impact in the workplace. With all the diversity of hazards, there is no unified approach to the development of the organisation's register, and this is an urgent problem, the solution of which will allow a qualitative approach to the issue of calculating and assessing professional risks. The article offers an accessible and practical-oriented method for identifying and developing a unified register of hazards of an organisation, which allows setting the uncertainty parameter of the register, which is an additional coefficient when calculating occupational risk in the workplace.
Feed additive for fishdiet with antioxidant and immunostimulating effect
Authors: Ponomarev Sergey , Levina Olga , Fedorovykh Yulia , Akhmedzhanova Aliya , Nikiforov-Nikishin Alexey , Klimov Victor
Published: January 2023

The increase in the production of aquaculture products confirms the relevance of the development of feed production in order to provide the industry with high-quality compound feeds and feed additives that meet modern requirements and biological needs of cultivated fish. Therefore, the development of aquaculture requires special attention to the feeding process and the use of full-fledged and environmentally safe feeds for all types of aquacultures. Antioxidants of natural origin are increasingly used in feed production. In the course of the work, the positive properties of antioxidant complexes containing the bioflavonoid dihydroquercetin in combination with vitamin E were studied when enriching the diet of a tilapia hybrid (Oreochromis mossambicus × Oreochromis niloticus). As a result of the research, it was found that the inclusion of dihydroquercetin in the composition of production feeds significantly improved productivity indicators and the main criteria for the formation of muscle mass in fish. The use of bioflavonoid dihydroquercetin allowed to increase productivity by 30.0%. The positive effect of the feed additive on morphological and biochemical parameters of blood was noted, which indicates an increase in natural resistance. The study of feed quality indicators confirmed the inhibition of oxidation processes in feed with the addition of dihydroquercetin. During the period of storage of feed in the experimental batch of feed, the level of peroxide number decreased by 3 times, and the acid number decreased by 28.4%. Taking into account the positive properties of bioflavonoid, it is recommended to further study the effectiveness of this biologically active additive in order to introduce it more widely into the practice of feed production.
Modern forms of foreign language distance learning in aquaculture
Authors: Boiko Anna , Laskina Evgeniya , Moisova Olga , Marchenko Svetlana
Published: January 2023

This article is devoted to a rather relevant topic of the 21st century. The subject of the analysis of the article is distance learning. The object of this article is a comparative analysis of distance learning in different countries. In recent years, the use of modern technical means has become a popular phenomenon in education all over the world. Information educational technologies have been intensively developed and increasingly used in the daily educational process along with traditional forms of education in many countries of the world. In this article, we consider the use of distance education in different countries, which helps to expand access to education and training for everyone. The choice of the topic is due to the relevance and the need to study distance education as an innovative form of education from various points of view. The authors analyze the use of distance learning sampled in various countries. The theoretical significance of the study lies in the fact that the data obtained can contribute to the deepened study of distance learning. The practical significance lies in the fact that the data obtained can be used in the course of modern pedagogy and methodology, in special courses on the problems of modern education.
Ways of increasing the milk productivity of cows, improving the quality and safety of live-stock products
Authors: Kuzminova Elena , Abramov Andrey , Koshaev Andrey , Semenenko Marina , Miroshnichenko Petr
Published: January 2023

The article presents the results of studies of the dependence of cows’ milk productivity on the level of lipid peroxidation and antioxidant defense in their body. For the experiment two groups of lactating cows were formed, 10 animals each: group 1 – livestock with a high concentration of lipid peroxidation products in the blood and a low level of antioxidants; group 2 – livestock with the values of these indicators within the reference interval. The results of the research indicate that in animals of the group 1 the average daily milk yield was lower by 9.9% relative to the values of the group 2. According to the quality characteristics and safety fac-tors of milk in cows with an imbalance in the LPO-AOD system relative to the group of animals with normal data, a decrease in the concentration of protein and fat was recorded with an increase in the concentration of somatic cells. Taking it into account, it seems relevant to use antioxidant substances for highly productive dairy cattle in order to increase milk productivity, improve the quality and safety of livestock products.
Prevention of air pollution swimming pool in the area of elevator construction using aspiration equipment
Authors: Efimov Denis , Krotova Olga , Tupolskikh Tatiana , Gucheva Natalia , Gordeeva Nadezhda
Published: January 2023

The purpose was to study the efficiency of the use of aspiration equipment of the BC type and its efficiency of use today in comparison with the advanced achievements of aspiration technology in the elevator industry for the process of creating air dilution and removing grain dust during the operation of equipment using the example of a modern silo elevator with a capacity of 20,000 tons, in grain production, including acceptance and storage of air-conditioned grains. In order to achieve the purpose of the study and answer the research questions about the effectiveness of the installations of battery cyclones of the BC type, a calculation was made on the amount of grain dust emitted for a period of 365 days of elevator operation in 3 shifts according to the "Temporary method of calculating planned indicators for the protection of atmospheric air of grain processing enterprises and elevators", in accordance with the "Calculation Method aspiration installations and explosion-discharge devices", series 14, issue 1 "Industrial safety of explosive grain storage and processing facilities".
The feasibility of using a probiotic to increase the egg productivity of chickens
Authors: Krotova Olga , Sangadzhieva Olga , Kedeeva Olga , Khalgaeva Kermen , Manzhikova Amulanga
Published: January 2023

The authors conducted a scientific and economic experience in LLC "Alyona". For research on the principle of analogues from chickens of the Rhodonite-2 cross, 2 groups (400 heads each) were formed from the daily age, taking into account gender, body weight and physiological condition. The duration of rearing of the repair young was 17 weeks, after which the bird was transferred to the laying hens workshop. The planting density, light mode, and feeding front of birds of all groups were the same and corresponded to the norms of VNITIP. Feeding was carried out with the same full-fledged compound feed, balanced in all nutrients and metabolic energy, with the inclusion of a probiotic SUB-PRO in the feed mixture of the experimental group. The introduction of a probiotic into the diet when raising chickens up to 13 weeks of age ensured a higher safety of young animals in the experimental group. The addition of a probiotic reduced feed costs. During the growing period of 1-13 weeks, feed costs per 1 kg of growth were lower in the experimental group, by 3.3% for 14-21 weeks and by 3.9% during the experiment period.
Corrective effect of probiotics on the work of the fish body in industrial aquaculture
Authors: Romanova Elena , Romanov Vasily , Lyubomirova Vaselina , Shadyeva Ludmila , Shlenkina Tatyana , Turaeva Elena , Vasiliev Alexander
Published: January 2023

Abstract. The world community associates the solution of the problem of food security with the development of aquaculture. The search for means of intensifying the production of a complete and easily digestible food protein in aquaculture is an important and urgent problem. Recently, probiotics, which have long been in demand in medicine, have been used in aquaculture to improve health, accelerate growth and improve the quality of fish in aquaculture. However, the correct choice of a probiotic for aquaculture is not an easy task, since in the modern world a wide range of probiotic preparations is produced in various forms, the dosage of which for aquaculture needs has not been developed, as well as the dosage and duration of their use have not been developed. Meanwhile, the use of probiotics in aquaculture can be expected to increase the production of marketable fish of improved quality. Probiotics for aquaculture should be resistant to gastric juice, able to colonize the intestines of fish, interact with the normobiota of the intestine and suppress pathogens. These properties are possessed by the probiotic "Sporotermin". It consists of freeze-dried spores of the bacteria Bacillus subtilis and Bacillus licheniformis. The content of viable spores in the preparation is not less than 3x10/9 CFU/g. The research results showed that the use of the probiotic "Sportermin" in aquaculture has a healing effect on fish, normalizes the structure of intestinal and liver tissues, affects the leukogram, activates the immune response system, reduces the level of oxidative stress, activating antioxidant defense enzymes and reducing the level of malondialdehyde. The research was carried out on the instructions of the Ministry of Agriculture of the Russian Federation.
Natural resources as an assessment factor in alternative GDP dynamics
Authors: Ushakov Denis
Published: January 2023

GDP is a key macroeconomic indicator which often serves as the basis for various classifications of the countries and also as a basis for the development of national and regional socioeconomic programs. The core methodology of GDP calculation is directly related to the US dollar, even under the current conditions of the extremely high international demand for this currency. However, in modern conditions, the importance of natural capital as a factor, that determines the level of economic development, is significantly increasing, the limited and rational use of natural resources should also be taken into account in economic progress of the countries assessing. For this very reason, the article offers an author’s own methodology of measuring GDP on the basis of world prices for natural resources (gold and also for the group of core food commodities). The paper tests the suggested methodology while analyzing the economic dynamics in the selected countries, from 2000 to 2019. Conclusions cover the issues of qualitative growth within the selected macroeconomic systems and also provide recommendations as to prospective directions for further application of the suggested methodology in statistical, analytical and forecasting practices around the world.
The use of informational technology for sustainable development: implications for students with different levels of life meaningfulness
Authors: Grishina Anastasia , Dyakova Elena , Pronenko Evgeny , Ismailov Ismail
Published: January 2023

The article is devoted to the study of the relationship between the fact of violation of psychological boundaries, as a consequence of active using of informational technologies in everyday life, the level of meaningfulness of life and coping strategies of students. The authors indicated the relevance of the study, analyzed theoretical approaches to the phenomenon of violation of psychological boundaries, as a consequence of the active use of informational technologies in the context of meaningful life and coping strategies. The article describes the procedure of empirical research. It has been shown that students with medium and high levels of meaningfulness of life have a tendency to expand the boundaries in the process of communication in the informational space. It was revealed that the leading behavioral strategy of students who are prone to psychological dependence on informational technologies, expressed in the impossibility of refusing them, as well as in their subjective significance, are the strategies of escape and avoidance of problem situations in real life. The study of the relationship between coping strategies and violation of psychological boundaries has shown that non-adaptive strategies of behavior and response, expressed in ignoring real problems, have a strong positive relationship with the active escape of students into the informational space, as well as an average positive relationship with expanding the boundaries of communication on the Internet.
Practice of rural settlement development in foreign countries
Authors: Yarisheva Tatyana , Vlasenko Irina
Published: January 2023

The article discusses the main approaches to the development of rural areas, that are used abroad. One of the strategic directions of most countries of the world is the revitalization of rural areas. The problems of rural areas, as a rule, are the same: the small number and aging of the population, underdeveloped or complete lack of infrastructure, the lack of, for example, a store, the minimum necessary services, Internet connection, stable work and, accordingly, wages have led to the fact that young people leave the village. At the same time, rural areas play a significant role in the development of the country, as they primarily ensure the country's food security, which is an integral part of national security, the preservation of historical and cultural heritage, the improvement of the demographic situation in rural settlements, the development of infrastructure, and the cultivation of environmentally friendly products. That is why, in modern conditions, foreign experience in solving problems of the popularization and development of rural settlements is of great interest.
Integrated workflow for rotary sidewall cores orientation: best practices and examples from planning to execution
Authors: Volonté Giorgio , Bersani Antonella , Berto Roberto , Cerri Riccardo , Pinelli Fabio
Published: January 2023

Over the last five years, the acquisition of rotary sidewall cores has become increasingly important in the O&G business. It is a matter of fact that the current tendency is to prefer them as a replacement to bottom hole cores, essentially for rig time related cost saving. This fact leads to force their use also for those types of characterisation usually reserved to larger size samples so, by consequence, some specific issues associated to their small size and to the lack of knowledge of in situ orientation have to be faced. For several applications such as geomechanics (whose experimental analysis require vertical plugs), petrophysics (permeability anisotropy, natural fracture orientation) and sedimentology, the original orientation, or its a posteriori identification, is mandatory in order to correctly measure properties relevant for reservoir management and studies. The full orientation of rotary sidewall cores requires to acquire or compute three couples of spatial information: high-side and low-side, wellbore end and formation end, trend and plunge of the samples. A dedicated workflow to a posteriori reconstruction of the orientation of large size rotary sidewall cores has been developed by means of the integration of multiple scale imaging techniques: images from logs and sidewall core are integrated through commercial software usually adopted for dip analysis. This approach has been successfully applied to several sidewall cores gathered in different geological environments. Currently, new coring and conveyance technologies allowing a predetermined sidewall cores orientation are emerging, increasing the reliability of the orientation workflow. Therefore, different scenarios of log planning strategy, operational solutions and post-coring analysis can be expected, depending on the confidence in the geological-structural interpretation and on the complexity of the technical environment. In all cases, it is extremely important to plan specific data acquisition and handling operations from wellsite to laboratory; including formalized minimum requirements and dedicated procedures, in order to maximize the quality of the subsequent laboratory analyses.
Effect of specimen size and shape on the mechanical properties measured on plugs subsampled from sidewall cores
Authors: Volonté Giorgio , Stenebraten Jørn , Papamichos Euripides
Published: January 2023

For several disciplines, the increasing acquisition of rotary sidewall cores (RSWC) in the oil and gas industry gives the opportunity for more extensive experimental rock characterization but, on the other hand, the limited amount of recovered material, their shape and orientation are not optimal for geomechanical experiments in the triaxial cell. These drawbacks can be overcome by performing experiments on properly shaped and oriented small diameter plugs subsampled from the RSWCs. These plugs are smaller than conventional ones, so the effects of both specimen shape (i.e., length over diameter L/D ratio) and size (i.e., diameter) on strength, stiffness (i.e., Young’s modulus), and dilation (i.e., Poisson’s ratio) must be carefully considered. In this work, an experimental study on specimen shape and size effects on rock mechanical properties has been tailored to materials and testing conditions generally encountered in petroleum related geomechanics. Triaxial compression experiments at three confining pressures have been performed on outcrop analogues of typical reservoir rock lithologies, i.e., two sandstones and two limestones, and within a range of shapes and sizes relevant for specimens prepared from RSWCs with emphasis on 10 mm diameter specimens. The strength, stiffness and dilation results were analysed and compared with relevant data and relations available in the literature. Then, analytical equations, useful for the practice of geomechanical experimental studies on RSWCs, have been derived to correlate mechanical properties measured on specimens of any shape or size to the ones obtainable on reference specimens.
Extensions of Active Flux to arbitrary order of accuracy
Authors: Abgrall Remi , Barsukow Wasilij
Published: January 2023

Active Flux is a recently developed numerical method for hyperbolic conservation laws. Its classical degrees of freedom are cell averages and point values at cell interfaces. These latter are shared between adjacent cells, leading to a globally continuous reconstruction. The update of the point values includes upwinding, but without solving a Riemann Problem. The update of the cell average requires a flux at the cell interface, which can be immediately obtained using the point values. This paper explores different extensions of Active Flux to arbitrarily high order of accuracy, while maintaining the idea of global continuity. We propose to either increase the stencil while keeping the same degrees of freedom, or to increase the number of point values, or to include higher moments as new degrees of freedom. These extensions have different properties, and reflect different views upon the relation of Active Flux to the families of Finite Volume, Finite Difference and Finite Element methods.
On the Magnus effect of a rotating porous circular cylinder in uniform flow: A lattice Boltzmann study
Authors: Imani Gholamreza , Mozafari-Shamsi Mohsen
Published: January 2023

In this paper, a multiple-relaxation-time–lattice Boltzmann method is used to simulate the steady fluid flow through and around a rotating porous circular cylinder in uniform flow. This study aims at investigating the effect of Darcy number (10−6≤Da≤10−2), velocity ratio (0≤VR≤2), and Reynolds number (Re = 20 and 40) on the Magnus lift as well as on the flow pattern and pressure coefficient inside and around the rotating porous cylinder. The results reveal that besides the enveloping and detached wakes reported in the literature for rotating solid cylinders, in this study, a new type of the wake called confined wake is observed within the rotating porous cylinders at high Darcy numbers and velocity ratios of less than one. It is seen that the Magnus lift increases almost linearly with the velocity ratio for Da≤10−3; however, through curve-fitting, the rate of increase is shown to decrease with Darcy number in a non-linear manner. For Darcy numbers higher than 10−3, the Magnus lift varies non-linearly with both the velocity ratio and Darcy number in such a way that, interestingly, for Re=40 and very high Darcy numbers of 7.5×10−3 and 10−2, the Magnus lift becomes negative showing a behavior called the inverse Magnus effect.
Non-Newtonian droplet breakup in a T-junction microdevice containing constriction induced asymmetric parallel branches
Authors: Kumari Pooja , Atta Arnab
Published: January 2023

Here, we describe the breakup and post-breakup dynamics of a non-Newtonian droplet of xanthan gum aqueous solution in asymmetric parallel branch microdevices. Our experimental results reveal that the droplet breakup regimes, namely, obstruction, tunnel, combined, non-breakup, and parallel, are the functions of xanthan gum concentration and the continuous phase flow rate. We examined the influence of fluid properties on droplet breakup stages by varying the xanthan gum concentration in an aqueous solution that exhibited increasing shear-thinning and elastic properties with its concentration. Four sequential stages (squeezing, transition, pinch-off, and filament thinning) are identified during the droplet breakup process. We found that upstream pressure controlled the squeezing stage, and fluid properties mainly steered the filament rupture stage. A complex interaction between elastic, capillary, and inertial forces further divided the final stage into the stretching and fluid-drainage stages. The Hencky strain characterized the formation of a persistent cylindrical filament in the stretching stage that decayed exponentially in the fluid-drainage stage. Eventually, this study highlights the significance of parallel branches with asymmetric geometric confinements on droplet splitting. Enhanced asymmetry is observed for the elongated filament, emphasizing the dominance of feedback from the downstream confinement.
Magnetohydrodynamics streamwise and cross flow of hybrid nanofluid along the viscous dissipation effect: Duality and stability
Authors: Lund Liaquat Ali , Yashkun Ubaidullah , Shah Nehad Ali
Published: January 2023

One of the most pressing issues in contemporary applied mathematics is the regulation of energy transfer via the application of external forces. The processes of heat transfer are affected by magnetic force, which has many practical uses in industry, engineering, and medicine. This research explores the magnetohydrodynamics (MHD) three-dimensional stable axisymmetric boundary layer over a permeable moving plate, which consists of water as a base liquid and binary distinct nanoparticles to generate a hybrid nanofluid. In all of these, flow beyond the boundary layer area might be calculated by a small crosswise velocity. As a result of its high thermal conductivity, a pair of distinct kinds of nanoparticles have been considered, namely alumina and copper, which are integrated into the base water. The mathematical model is built within a boundary of specified geometry and then converted into a set of ordinary differential equations (ODEs). Resultant ODEs are solved numerically using the technique of three-stage Lobatto IIIa in bvp4c solver in 2017, MATLAB software. Results revealed that two branches exist in certain ranges of moving parameter. The impacts of an increasing physical parameter on profiles of velocities and temperature with skin friction as well as with heat transfer rate are represented in graphs. Furthermore, as the volume fraction of copper increases, so does the skin friction coefficient in the positive direction of λ. The effect of viscous dissipation on the temperature profile in the z-direction has the same rising results as observed in the x-direction. According to the results of the temporal stability analysis, the upper branch is realizable and stable.
Numerical investigation on flow and heat transfer mechanism of corrugated cooling channel in turbine blades
Authors: Wu Chenhan , Yang Xiaoquan , Tang Xiaolong , Ding Jue , Weng Peifen
Published: January 2023

Aiming at the key scientific problems of strengthening cooling and heat dissipation of turbine blades, a new type of corrugated channel cooling structure was proposed in this work. Refined numerical simulation was carried out in six different corrugated channels, and the physical mechanism of flow and heat transfer was analyzed in detail. The results show that the corrugated channel has smaller flow resistance than the ribbed channel. Among the corrugated channels, the heat transfer effects of sinusoidal, triangular, and sawtooth2 corrugated channels are stronger than rib corrugated channel at the high Reynolds number, and these effects are distributed evenly. Within the six kinds of corrugated channels, the sinusoidal corrugated channel has the best comprehensive heat transfer effect. The blades with sinusoidal corrugated channels have better cooling effect due to the significant increase in heat transfer coefficient on the inner channel surface, and the channel contraction area plays a decisive role in the enhancement of the cooling effect. The heat transfer capacity of the sinusoidal corrugated channel is closely related to the shape of the corrugation, and the heat transfer effect reaches for the best near the waveform H/L =  0.115. The physical mechanism of heat transfer enhancement of the corrugated channel is revealed in this paper, which can provide a reference for the design of the cooling structure of aeroengine blades in the future.
Spreading dynamics of the viscous droplet impacting on a spherical particle
Authors: Fan Zhiheng , Liu Daoyin , Pan Suyang , Ma Jiliang , Chen Xiaoping
Published: January 2023

The dynamic behavior of droplets in the impingement process with particles has attracted extensive interest due to its widespread industrial applications. In this study, collision experimentation was carried out to investigate the spatial and temporal variation of droplets on a target particle surface by utilizing high-speed photography. Energy conversion and force analysis were conducted through theoretical analysis. Moreover, we captured the microscopic and evolutionary features of droplets in detail by image processing. The dimensionless liquid film thickness in the maximum spreading state is primarily determined by its spreading area. The Weber number can be used to calculate the maximum spreading area of droplets for liquids with a specific viscosity and droplet-to-particle size ratio. The time-evolved liquid film morphology and spreading area of a highly viscous liquid show a different trend compared to that of the low-viscous liquid. When the liquid film is not broken, the maximum dimensionless spreading area is linearly related to the Weber number. At low Weber numbers and high Reynolds numbers, droplets exhibit more pronounced oscillation characteristics. The oscillation period of the collision is related to the droplet-to-particle size. The liquid film thickness decreases as the Weber and Reynolds numbers rise. As for the low-viscous liquid, a low Weber number leads to a periodic change in the dynamic contact angle. A decrease in the Reynolds number for the highly viscous droplets generates a greater dynamic contact angle. The recoiling of the liquid film results in a more significant reduction in the dynamic contact angle.
The modulation instability of shallow wake flows based on the higher-order generalized cubic-quintic complex Ginzburg–Landau equation
Authors: Fu Lei , Han Xiaofeng , Dong Huanhe , Yang Hongwei
Published: January 2023

In the context of the parallel flow hypothesis, we derive a higher-order generalized cubic-quintic complex Ginzburg–Landau (GCQ-CGL) equation to describe the amplitude evolution of shallow wake flow from the dimensionless shallow water equations by using multi-scale analysis, perturbation expansion, and weak nonlinear theory. The evolution model includes not only the slowly changing envelope approximation but also the influence of higher-order dissipation, dispersion, and cubic and quintic nonlinear effects. We give the analytical solution of the higher-order GCQ-CGL equation based on the ansatz and coordinate transformation methods, and we discuss the influence of the higher-order dissipation coefficient on the amplitude and frequency of the wake flow by means of three-dimensional diagrams, contour maps, and plane graphs. The subsequent linear stability analysis gives a theoretical basis for the modulation instability (MI) of plane waves, and the linear theory predicts the instability of any amplitude of the main waves. Finally, we focus on the MI of shallow wake flows. Results show that the MI gain function is internally related to the background wave number, disturbance wave number, background amplitude, disturbance expansion parameter, and dissipation coefficient. The area of the MI decreases as the higher-order dissipation coefficient decreases.
On the effects of fluid elasticity and gas holdup on Taylor bubble rising dynamics in viscoelastic media
Authors: Ba Qixin , Yuan Wenjun , Mei Mei
Published: January 2023

In this work, the rise of Taylor bubbles in a vertical tube filled with viscoelastic media is investigated by means of volume-of-fluid-based direct numerical simulations. The rheological behaviors of the nonlinear viscoelastic liquids are described by the exponential Phan-Thien–Tanner constitutive model. The applicability of our simulations to capture the liquid film around a Taylor bubble has been validated by comparisons with numerical and experimental data in the literature. The effects of fluid elasticity [indicated by the Weissenberg (Wi) number] and gas holdup are mainly discussed in respect of Taylor bubble dynamics (e.g., rising velocity, flow field, stress field, liquid film, and so on). Our results show that the Taylor bubble steady rise velocity is logarithmically correlated with Wi and the slope is nearly constant at low Wi numbers. When the fluid elasticity is moderate, the viscoelastic stress in the liquid film is large, and the rising bubble is stretched to form a thin filament tail with a negative wake. Moreover, the fluid elasticity has negligible effects on the steady bubble rising velocities and the liquid film thickness for large Wi numbers. With increasing fluid elasticity and gas holdup, the long Taylor bubble fluctuates due to the surrounding liquid pulling deformation and gas pressure. The viscoelastic stress profiles exhibit a major non-monotonic dependence on the distance to the walls, which seems to be squeezed as the liquid film gets thinner under high elasticity. The dynamical Taylor bubble is found to be significantly affected by the surrounding fluid viscoelasticity and partially independent of the gas holdup, which will guide the design of microreactors in chemical applications.
Investigation of hypersonic cone boundary layer stability regulation with plasma actuation
Authors: Yang Hesen , Liang Hua , Zhang Chuanbiao , Wu Yun , Zong Haohua , Su Zhi , Kong Yakang , Zhang Dongsheng , Li Yinghong
Published: January 2023

Boundary layer transition has always been a frontier in the field of fluid mechanics, and hypersonic boundary layer stability experiments can help reveal the physical mechanisms behind such transitions. In particular, the regulation of unstable waves in boundary layers is critical for transition prediction and control. Plasma actuation is a popular flow control method that has made progress in moderating the stability of supersonic boundary layer. However, there have been few studies on regulating the stability of hypersonic boundary layers with plasma actuation. In this paper, wind tunnel experiments are carried out under Mach 6 flow to study the stability regulation of a hypersonic sharp cone boundary layer with nanosecond pulsed plasma actuation. First, the typical characteristic structure of the rope-like structure is captured by the high-speed schlieren method. Then, combining the sensor results and theoretical analysis, the rope-like structure and the dominant instability wave resolved by the schlieren power spectrum density method are determined to correspond to the second-mode wave. The characteristic unstable quasi-ordered structure of the boundary layer under actuation is then extracted, and the impact effect and modulation effect of this structure on the second-mode wave are analyzed. Finally, the mechanism by which actuation influences the boundary layer instability is studied using proper orthogonal decomposition. The results show that actuation can enhance boundary layer pulsation, and the coupling effect between the actuation and boundary layer can produce regular unstable quasi-ordered structures. The intrinsic mechanism works by impinging on and modulating the second-mode waves, and there are characteristic modes of the rope-like structure and the unstable structures distributed over the whole flow-direction range. This verifies the ability of plasma actuation to stimulate the instability of hypersonic cone boundary layers and provides technical support for the further development of transition control methods.
Slope effect on junction fire with two non-symmetric fire fronts
Authors: Ribeiro Carlos , Xavier Viegas Domingos , Raposo Jorge , Reis Luís , Sharples Jason
Published: January 2023

Background In Pedrógão Grande on 17 June 2017, two fire fronts merged and the propagation of the fire was influenced by the interaction of these non-symmetric fire fronts. Aims This wildfire motivated us to study a junction fire with two non-symmetrical fire fronts. The analysis of the movement of the intersection point and the angle (γ) between the bisector of the fire lines and the maximum rate of spread (ROS) direction is of particular relevance. Methods The study was carried out at Forest Fire Laboratory of the University of Coimbra in Lousã (Portugal) with laboratory experiments. Key results We found that, for small rotation angles (δ), the non-dimensional ROS of the intersection point depends on the slope angle (α) and the initial angle between fire fronts. Conclusions For high α, the non-dimensional ROS was highly influenced by the convection process and γ where the maximum ROS occurred, increased when δ increased. However, the radiation process was more relevant for lower α and influenced the non-dimensional ROS. For these cases, the maximum spread direction was close to that of the fire line bisector. Implications The present work aimed to explain fire behaviour during the Pedrógão Grande wildfire.
Seroconversion following Heplisav-B, hepatitis B vaccine (recombinant), adjuvanted, in patients with end-stage renal disease at an urban safety net hospital
Authors: Walsh Connor , McDaniel Kathryn , Lindsey Lindsey , Johnson Sarah , Walton Ted
Published: January 2023

Purpose

Heplisav-B is a novel recombinant adjuvanted vaccine for hepatitis B virus (HBV) that has been approved as a 2-dose regimen and shown to have similar seroconversion rates in healthy adults as single-antigen HBV vaccines. More data are needed to determine whether similarly high rates of seroconversion and immunity are observed in immunocompromised patient populations such as in patients with end-stage renal disease (ESRD) on hemodialysis.

Methods

Patients with ESRD who presented for emergency-only hemodialysis and either were HBV vaccine naive or had a hepatitis B surface antibody (anti-HBs) titer of less than 10 IU/mL received 3 standard 20-μg doses of Heplisav-B at week 0, week 4 (±2 weeks), and week 24 (±2 weeks), with anti-HBs titer measured at week 28 (±2 weeks).

Results

Thirty-two patients received at least one dose in the study timeframe, with 24 patients completing the vaccine series and measurement of anti-HBs titer. The mean age of the patients was 46 years, and 58% of patients were male. Of the 24 patients who completed the vaccine series, 20 (83%) seroconverted after the third dose. Three of the 4 patients who did not seroconvert after 3 doses were revaccinated with an additional 20-μg dose, and 2 of the 3 patients had an anti-HBs titer of greater than 10 IU/mL 4 weeks after this dose.

Conclusion

Patients with ESRD who received three 20-μg doses of recombinant HBV vaccine had a seroconversion rate of 83%, representing a similar seroconversion rate and fewer doses of vaccine as compared to the standard HBV vaccine regimen for patients with ESRD.