bluuebunny/crossref_metadata_2025 huggingface dataset:
The search for treatment springs is the basis of their protection
Authors: Tashpulatova S.A. , Mamarakhimov O.M. , Tursunova Sh.A. , Makhmudova M.M. , Yulchiyeva M.T.
Published: December 2023

Chemical analysis of 31 spring waters of Gallaorol in Jizzakh region of Uzbekistan was analyzed. Instead of the local names of the springs, they were specially numbered to facilitate the research process and not to confuse the spring waters. The purpose of the study is to check whether the springs located in the area have healing properties. The research was focused on checking indicators such as general mineralization of the spring water sample, carbon dioxide, hydrogen sulfide, silicon (IV) oxide, silicic acid, carbon content (organic), iodine, bromine, boron, and ferrum. The results of chemical analysis were compared with the mineral water requirements of the Republic of Uzbekistan. According to the results, it was found that all 31 spring waters do not meet the requirements of mineral medical water.
Estimation of greenhouse gas emissions during the cultivation of industrial hemp (Cannabis sativa L.) in different temperature regimes
Authors: Danilova Natalia , Gordeev Aleksandr , Gilmutdinova Ilsina , Kuryntseva Polina , Selivanovskaya Svetlana
Published: December 2023

The emission of carbon dioxide from the soil is an urgent problem, as it not only contributes to climate change, but also affects the reduction of the carbon pool in the soil, which negatively affects its fertility. Cultivation of crops with fast growth, high biomass and atmospheric carbon fixation capacity is effective in terms of reducing soil carbon dioxide emissions and organic carbon storage. The purpose of this work was to evaluate greenhouse gas emissions from the cultivation of industrial hemp (Cannabis sativa L., 1753) in different temperature regimes – 15ºС, 20ºС and 30ºС. Soil without plants was used as a control. The respiration activity of the soil microbial community was assessed on the 1st, 7th, 14th, 28th, 42nd, 56th, 70th, 84th and 98th days of incubation. Biomass of plants was measured on the 98th day. It was established that there were no differences in the respiration activity of the control soil and the soil under industrial hemp (Cannabis sativa L., 1753) at the beginning of the experiment, however, from the 14th day, the respiration activity was significantly lower in the soil without plants. The influence of the temperature regime on respiration activity was established after 56 days of the experiment. The influence of the temperature regime of vegetation on the morphometric parameters of hemp has been established: the largest biomass of plants was found at a colder incubation temperature (15ºС). It has been established that the emission of greenhouse gases from the soil during the cultivation of industrial hemp (Cannabis sativa L., 1753) is higher compared to pure soil and depends on the temperature regime.
Experimental analysis of microges installation for existing water flows in industrial plants
Authors: Zokhidov O.U. , Khoshimov O.O. , Khalilov Sh.Sh.
Published: December 2023

Calculation and analysis of the existing potential of low-pressure water flow at the engineering facilities of JSC “NGMK” (Joint Stock Company, Navoi Mining and Metallurgical Combine) is carried out, nomogram for determining the power of water flow based on the head and flow rate is created. The impeller design was analyzed by means of CAD (Computer Aided Design System) SOLIDWORKS software package, the optimal number of water impeller blades was revealed.
Productivity of binary vetch-and-grass mixtures in the conditions of a plain agricultural landscape of the western Ciscaucasia
Authors: Skamarokhova Alexandra , Kravchenko Roman , Yurin Denis , Svistunov Andrey , Gneush Anna
Published: December 2023

The purpose of this study is to establish the most suitable components in terms of productivity and quality for the effective cultivation of a binary vetch-and-grass mixture for the purpose of further harvesting haylage from it. The studies were carried out on winter crops: vetch + wheat and vetch + triticale; the soils are represented by leached, low-humus, powerful chernozems, located in the conditions of the alluvial-loess plain agricultural landscape of the Western Ciscaucasia (Krasnodar Territory) with plowed steppes. The subjects of the study were: Triticum aestivum L. variety of Tanya; Triticosecale Wittm. ex A. Camus variety of Khleborob; Vicia pannonica Granz varieties of Chernomorskaya and Orlan; Vicia vilossa op Roth varieties of Lugovskaya-2 and Glinkovskaya. Two cuttings were studied in different phenological phases. According to the results of the study, when mowing in the first ten days of May, the most productive grass mixtures are winter wheat of Tanya + Hungarian vetch of Orlan (green material – 102.6 c/ha, dry weight – 19.7 c/ha) and winter triticale of Khleborob + downy vetch of Glinkovskaya (100.2 c/ha of green material and 20.0 c/ha of dry mass). According to the results of laboratory studies, the most nutritious grass mixture was based on winter triticale and downy vetch.
The influence of surfactants of different classes on the toxicity of diesel fuel forSaccharomycetes
Authors: Zhdanova Galina , Cherkasov Danila , Vyatchina Olga , Yampolskaya Tatyana , Zhou Qixing , Stom Devard
Published: December 2023

The effect on the survival of the yeastS. cerevisiaeof mixtures of diesel fuel (summer variety) with four representatives of different classes of surfactants – cationic (cetyltrimethylammonium bromide), anionic (sodium dodecyl sulfate), nonionic (Tween-80) and polymeric (polyvinyl alcohol) – was studied. It was shown that diesel fuel and two representatives of the classes of anionic and cationic surfactants (sodium dodecyl sulfate and cetyltrimethylammonium bromide) in the mixture exhibited higher toxicity than when exposed individually. At the same time, the toxicity of diesel fuel mixed with a nonionic surfactant (Tween- 80) and a polymer surfactant (polyvinyl alcohol) was comparable to their individual toxicity.
ESG ratings of rural areas as a tool for sustainable development of agriculture in the region
Authors: Anzilevich Daniil , Balashova Natalya , Kolpakova Ekaterina , Nemchenko Alexander , Korobeinikov Dmitry
Published: December 2023

The goal and result of the study was the development of a new methodology for creating an ESG rating of rural areas, built on the basis of a hierarchical system of private, summary and integral indicators characterizing the environmental, social and corporate components of sustainable development. The proposed approach to constructing an ESG rating is distinguished by a combination of methods of comparative static and trend analysis, differentiation of rural areas into developed, depressed, developing and crisis, which will allow standardizing measures of state support for the sustainable development of agriculture and rural areas in the context of selected types of regions.
Ore-magmatic concentres in Uzbekistan
Authors: Sidorova I.P. , Saxobidinov R.I. , Golovko E.A.
Published: December 2023

This paper presents a study of ore-magmatic concentres in Uzbekistan. New data of integrated geological and geophysical investigations of Central-Kyzylkum, Nurata, Chatkal-Kurama, Baisun, Sultanuvais ore-magmatic concentres are presented.
Increasing the efficiency of rocks distribution tools in air-assisted well drilling
Authors: Mustafayev O.B. , Sobirov Sh.B.
Published: December 2023

One of the main ways to ensure the normal temperature regimes of the rock crushing tool is to cool the temperature of the cleaning compressed air delivered to the well, that is, to eliminate the heat spread in the rock crushing tool by transferring the cooled air. However, the experience of drilling wells with compressed air shows that in order to effectively regulate the temperature regimes of the rock-breaking tool, it is necessary to provide optimal drilling regimes together with the cooling of the compressed air temperature.
Estimation of the reliability of NPP auxiliary needs reservation using the phase change accumulator
Authors: Yurin Valeriy
Published: December 2023

The installation of a phase transition accumulator at NPP will ensure their effective participation in covering the uneven daily schedule of electrical loads. The heat stored in the accumulator can be used to generate steam for an additional turbine, which, when the NPP is blackout, is able to remove the residual heat from the reactors using the removed energy of the core, the excess of which can be stored in the accumulator and used if necessary. The authors studied the reliability of plants own needs redundancy based on the developed systems for a range of fundamental factors. The results showed that the installation of developed thermal storage systems with an additional turbine at NPPs will significantly improve the safety level of plants.
Analysis of modern nuclear energy technologies in Russia and their comparative analysis with other types of electricity generation in Russia and the world
Authors: Bobrova E.O. , Berkov N.A. , Morozova Т.А. , Makovetsky M.Y. , Markov S.N.
Published: December 2023

In the modern world, the issue of energy consumption is very acute. The non-renewability of resources such as oil, gas, coal, one should think about using alternative sources of electricity, such as wind, solar radiation, and the heat of the earth’s interior. However, climatic and geographical conditions do not allow their use everywhere, and the technologies necessary for this have not yet been developed. The study proposes scientific approaches related to the development of modern technologies for the use of various types of energy.
Validation of the two-fluid model of interaction of a water jet with a melt
Authors: Melikhov O.I. , Melikhov V.I. , Yakush S.E. , Finoshkina D.V.
Published: December 2023

The model of interaction of a water jet with a melt was validated using experimental data from experiments in which a water jet was injected into a vessel filled with a melt of a eutectic alloy of lead and bismuth. The model is based on the VOF method for immiscible liquids. In the experiments, the experimental data of which were used to validate the model, high-speed X-ray photography was carried out to trace the evolution of the shape of a water jet after its injection into a vessel with a melt. The configurations of the water jet that disintegrates in the melt volume obtained in the calculations were compared with photographs taken during the experiment. Good qualitative agreement between calculations and experiment was obtained. A quantitative comparison of the jet propagation in the melt showed that the jet propagation speed in the calculations is overestimated relative to the experiments at a high water injection rate. This is due to the fact that the model does not take into account the boiling of water on the surface of a hot melt, which is planned to be done in future activity.
Ex-vivo-Mikro-CT in der Augenheilkunde: Probenbehandlung und -kontrastierung für die 3D-Darstellung
Authors: Keiler Jonas , Stahnke Thomas , Guthoff Rudolf F. , Wree Andreas , Runge Jens
Published: December 2023

Die röntgenbasierte Mikrocomputertomografie (Mikro-CT) bietet ein weitgehend zerstörungsfreies Bildgebungsverfahren zur Visualisierung und Analyse interner Strukturen im Ex-vivo-Auge mit
hohen Auflösungen. Im Gegensatz zu anderen hochauflösenden Imaging-Verfahren ermöglicht die Mikro-CT die räumliche Erfassung größerer und komplexerer Gewebestrukturen wie der vorderen
Augenkammer. Spezielle Kontrastierungsmethoden helfen, die Absorptionseigenschaften von ansonsten nur schwach röntgenopaken Weichteilgeweben zu verstärken. Die vor allem in der
Rasterelektronenmikroskopie verwendete Kritisch-Punkt-Trocknung (KPT) bietet ein zusätzliches Werkzeug zur Verbesserung der differenziellen Kontrasteigenschaften im Weichteilgewebe. Bei der
Darstellung intraossärer Weichteilgewebe, wie den ableitenden Tränenwegen, liefert die Probenbehandlung durch Entkalkung mit Ethylendiamintetraessigsäure und anschließender KPT gute
Ergebnisse für die Mikro-CT. Die Mikro-CT kann für verschiedenste Fragestellungen in 1. Grundlagenforschung, 2. anwendungsbezogenen Studien in der Augenheilkunde (z. B. Evaluierung der
präklinischen Applikation von Microstents zur Glaukombehandlung oder Analyse der Positionierung von Intraokularlinsen), aber auch 3. als Ergänzung für die ophthalmologische Histopathologie
eingesetzt werden.
Chromatic Swept-Source Laser Scanning – Konzept für eine zellauflösende konfokale Laserspaltlampe?
Authors: Sperlich Karsten , Bohn Sebastian , Reichert Klaus-Martin , Stolz Heinrich , Guthoff Rudolf F. , Stachs Oliver , Allgeier Stephan
Published: December 2023

Hintergrund Die In-vivo-Charakterisierung der Morphologie des Epithelgewebes der Kornea ist von erheblicher Bedeutung für die Diagnostik, die Krankheitsprognose und die Entwicklung
einer Behandlungsstrategie bei Oberflächenerkrankungen des Auges. Im Gegensatz zu vielen alternativen Methoden bietet die In-vivo-Konfokalmikroskopie der Kornea (CCM) nicht nur eine
makroskopische Beschreibung des kornealen Gewebes, sondern ermöglicht dessen Darstellung mit zellulärer Auflösung. Die Translation der CCM von der Forschung in die klinische Praxis ist
jedoch durch die komplexe und bisher weitgehend manuelle Bedienung der verfügbaren CCM-Systeme erheblich eingeschränkt. Für Tiefenschnittbilder, analog zur konventionellen
Spaltlampenmikroskopie, müssen außerdem aufgrund der frontalen Orientierung des Bildfeldes bei der CCM in aufwendigen Tiefenscans Volumenaufnahmen erzeugt werden, aus denen sich anschließend
Tiefenschnitte berechnen lassen. Bereits die reine Aufnahmedauer liegt hierbei im Bereich von Sekunden, zusätzlich müssen Bewegungsartefakte aufwendig korrigiert werden.

Material und Methoden Dieser Beitrag stellt das Konzept und die Optiksimulation eines neuen Bildgebungsverfahrens auf Basis eines Swept-Source-Lasers in Verbindung mit einer
speziellen chromatischen Optik vor. Hierbei verändert der Laser periodisch seine Wellenlänge und wird aufgrund der wellenlängenabhängigen Aberration der chromatischen Optik in
unterschiedlichen Tiefen fokussiert.

Ergebnisse Die Ergebnisse der Optiksimulation versprechen eine gute optische Auflösung bei einer Abbildungstiefe von insgesamt 145 µm.

Schlussfolgerung Das langfristige Ziel ist die konfokalmikroskopische zellauflösende In-vivo-Bildgebung der Kornea in Echtzeit mit verschieden orientierten Schnittrichtungen.
Hydrogen Sulfate-Templated Synthesis of a Bis-Ferrocene Macrocycle
Authors: Beeren Sophie R.
Published: December 2023

A bis-ferrocene macrocycle was synthesized by reversible acylhydrazone formation under thermodynamic control, starting from a ferrocene functionalized with hydrazide and protected aldehyde moieties. A hydrogen sulfate anion acts as a template to direct the synthesis specifically toward the macrocyclic dimer, due to a weak but selective binding interaction. This work highlights the utility of dynamic combinatorial chemistry as an approach to macrocycle synthesis.
Selection of Quality Indicators to Evaluate Quality of Care for Patients with Esophageal Atresia Using a Delphi Method
Authors: Teunissen Nadine M. , Brendel Julia , Heurn L.W. Ernest van , Ure Benno , Wijnen Rene , Eaton Simon ,   on behalf of the EPSA|ERNICA Registry Group,   the EA Quality of Care Initiative
Published: December 2023

Objective Survival of neonates with esophageal atresia (EA) is relatively high and stable, resulting in increased attention to optimizing care and longer-term morbidity. This study aimed to reach consensus on a quality indicator set for benchmarking EA care between hospitals, regions, or countries in a European clinical audit.

Methods Using an online Delphi method, a panel of EA health care professionals and patient representatives rated potential outcome, structure, and process indicators for EA care identified through systematic literature and guideline review on a nine-point Likert scale in three questionnaires. Items were included based on predefined criteria. In rounds 2 and 3, participants were asked to select the five to ten most essential of the included indicators.

Results An international panel of 14 patient representatives and 71 multidisciplinary health care professionals representing 41 European hospitals completed all questionnaires (response rate: 81%), eventually including 22 baseline characteristics and 32 indicators. After ranking, 10 indicators were prioritized by both stakeholder groups. In addition, each stakeholder group highly prioritized one additional indicator. Following an additional online vote by the other group, these were both added to the final set.

Conclusion This study established a core indicator set of twenty-two baseline characteristics, eight outcome indicators, one structure indicator, and three process indicators for evaluating (quality of) EA care in Europe. These indicators, covering various aspects of EA care, will be implemented in the European Pediatric Surgical Audit to enable recognition of practice variation and focus EA care improvement initiatives.
On non-local electrical transport in anisotropic metals
Authors: Baker Graham , Valentinis Davide , Mackenzie Andrew P.
Published: December 2023

We discuss various aspects of nonlocal electrical transport in anisotropic metals. For a metal with circular Fermi surface, the scattering rates entering the local conductivity and viscosity tensors are well-defined, corresponding to eigenfrequencies of the linearized collision operator. For anisotropic metals, we provide generalized formulas for these scattering rates and use a variational approximation to show how they relate to microscopic transition probabilities. We develop a simple model of a collision operator for a metal of arbitrary Fermi surface with finite number of quasi-conserved quantities, and derive expressions for the wavevector-dependent conductivity σ(q) and the spatially-varying conductivity σ(x) for a long, narrow channel. We apply this to the case of different rates for momentum-conserving and momentum-relaxing scattering, deriving closed-form expressions for σ(q) and σ(x) — beyond generalizing from circular to arbitrary Fermi surface geometry, this represents an improvement over existing methods which solve the relevant differential equation numerically rather than in closed form. For the specific case of a diamond Fermi surface, we show that, if transport signatures were interpreted via a model for a circular Fermi surface, the diagnosis of the underlying transport regime would differ based on experimental orientation and based on whether σ(q) or σ(x) was considered. Finally, we discuss the bulk conductivity. While the common lore is that “momentum”-conserving scattering does not affect bulk resistivity, we show that crystal momentum-conserving scattering — such as normal electron-electron scattering — can affect the bulk resistivity for an anisotropic Fermi surface. We derive a simple formula for this contribution.
Transport signatures of plasmon fluctuations in electron hydrodynamics
Authors: Zverevich Dmitry , Levchenko Alex
Published: December 2023

In two-dimensional electron systems, plasmons are gapless and long-lived collective excitations of propagating charge density oscillations. We study the fluctuation mechanism of plasmon-assisted transport in the regime of electron hydrodynamics. We consider pristine electron liquids where charge fluctuations are thermally induced by viscous stresses and intrinsic currents, while attenuation of plasmons is determined by the Maxwell mechanism of charge relaxation. It is shown that, while the contribution of plasmons to the shear viscosity and thermal conductivity of a Fermi liquid is small, plasmon resonances in the bilayer devices enhance the drag resistance. In systems without Galilean invariance, fluctuation-driven contributions to dissipative coefficients can be described only in terms of hydrodynamic quantities: intrinsic conductivity, viscosity, and plasmon dispersion relation.
Adenine’s band strength at cryogenic temperatures
Authors: Rego V. P. , Oliveira P. R. B. , da Silveira E. F.
Published: December 2023

Infrared observations of the interstellar medium have unveiled the existence of numerous solid-phase molecules. The recent detection of uracil within the (162173) Ryugu asteroid has opened new prospects for the discovery of additional compounds, including nitrogenous bases, in the near future. To facilitate the comprehension, identification, and observation of these substances within astrophysical environments, precise measurements of their infrared band strengths are crucial. In this study, we present the outcomes of laboratory experiments conducted to investigate the behavior of adenine at various temperatures. The measured band strength from 3600 to 1970 cm−1 was determined to be 3.21⋅10−16 cm molecule−1. Additionally, as the temperature decreased, its behavior exhibited a well-fitted second-degree polynomial function. Notably, the experiments indicated no permanent phase changes or hysteresis during the cool-down and warm-up processes, further elucidating the thermal properties of adenine.
Analysis and mitigation of an oscillating background on hybrid complementary metal-oxide semiconductor (hCMOS) imaging sensors at the National Ignition Facility
Authors: Hassard B. R. , Dayton M. S. , Trosseille C. , Benedetti L. R. , Chen H. , Döppner T. , Durand C. E. , Hall G. N. , Morioka S. B. , Nyholm P. R. , Ping Y. , Sharp A. , Carpenter A. C. , Nagel S. R.
Published: December 2023

Nanosecond-gated hybrid complementary metal-oxide semiconductor imaging sensors are a powerful tool for temporally gated and spatially resolved measurements in high energy density science, including inertial confinement fusion, and in laser diagnostics. However, a significant oscillating background excited by photocurrent has been observed in image sequences during testing and in experiments at the National Ignition Facility (NIF). Characterization measurements and simulation results are used to explain the oscillations as the convolution of the pixel-level sensor response with a sensor-wide RLC circuit ringing. Data correction techniques are discussed for NIF diagnostics, and for diagnostics where these techniques cannot be used, a proof-of-principle image correction algorithm is presented.
Time-dependent clay gels: Stepdown shear rate behavior, microstructure, ageing, and phase state ambiguity
Authors: Leong Y. K. , Clode P. L.
Published: December 2023

To study the time-dependent properties of clay gels in the structural rejuvenation mode, a combination of the stepdown shear rate method and an ageing test is advocated. In this mode, the structural development process at two different initial equilibrium states during the low stepdown shear rate and the rest period of the ageing test were followed. The roles played by the electric double layer (EDL) repulsive force in this structural development process with and without shear, for platelet sodium montmorillonite or NaMnt, hectorite and Laponite gels, and fibrous sepiolite gels were assessed. The response of the stepdown shear stress and ageing yield stress reflects the action of these forces on the structural rejuvenation kinetics and the type of structure formed. The platelet clay gels with their strong EDL repulsive particle interaction commenced the structural development process immediately and formed an open network structure. This process is short in shear and takes years when without. The fibrous sepiolite gel with its weak EDL repulsive interaction did not display structural rejuvenation in shear and only showed a significant yield stress increase after the first few hours of ageing. An additional issue concerning the stability of the isotropic liquid (IL) phase state of dilute Laponite dispersions was addressed. These dispersions aged for >9 years, displaying that yield stress and network structure confirmed that the IL phase is unstable. A low energy path available for Laponite particles to aggregate was discussed. A new method for determining the flocculate phase state was also presented.
Acoustic real second-order nodal-loop semimetal and non-Hermitian modulation
Authors: Yue Zichong , Zhang Zhiwang , Cheng Ying , Liu Xiaojun , Christensen Johan
Published: December 2023

The unique features of spinless time-reversal symmetry and tunable ℤ2 gauge fields in artificial systems facilitate the emergence of topological properties in the landscape, such as the recently explored Möbius-twisted phase and real second-order nodal-loop semimetals. However, these properties have predominantly been proposed only in theoretical frameworks. In this study, we present a cunningly designed blueprint for realizing an acoustic real second-order nodal-loop semimetal through the incorporation of projective translation symmetry into a three-dimensional stacked acoustic graphitic lattice. Additionally, we introduce non-Hermitian modulation to the topologically protected propagation of degenerate drumhead surface and hinge states, which depend on the specific on-site gain and loss textures. It should be emphasized that this demonstration can be extended to other classical wave systems, thereby potentially opening up opportunities for the design of functional topological devices.
Research on passive deformation and hydrodynamic performance of a biomimetic cownose ray in gliding motion through fluid-structure interaction analysis
Authors: Xu Tongshi , Luo Yang , Hou Zhexing , Huang Qiaogao , Cao Yong , Pan Guang
Published: December 2023

This work explores the impact of passive deformation on the hydrodynamic performance of cownose rays gliding at various angles of attack (AoA) and pectoral fin stiffness. We employ a partitioned fluid-structure coupling scheme to resolve the dynamic interaction between the fluid and structure. Specifically, the incompressible Navier–Stokes equations are solved through the finite volume method, while structural deformation is addressed via the finite element method. A co-simulation engine is utilized for communication and coordination between the fluid and structural solver. Furthermore, an implicit coupling scheme is implemented to ensure numerical stability. Our results demonstrate that passive deformation of the pectoral fin would stabilize the gliding motion with increased drag and lift but reduced pitching moment. The lift-to-drag ratio is improved slightly at any angle of attack, with the maximum increase reached at an AoA of ±7.5°. Pectoral fin stiffness can influence passive deformation significantly, and the minimal stiffness leads to the most evident impact on gliding lift enhancement and pitching moment reduction under the parameters considered in this work. This study may provide insight into the control strategy of optimal gliding angle of attack and the selection of material properties of flexible fins in the design of high-performance biomimetic underwater gliders.
Optimization of the collective Thomson scattering diagnostic for the GDT open magnetic trap
Authors: Shalashov A. G. , Gospodchikov E. D. , Khusainov T. A. , Solomakhin A. L.
Published: December 2023

The collective Thomson scattering of high-power millimeter-wave radiation on plasma density fluctuations (CTS) is widely used for diagnosing the velocity distribution function of energetic ions in fusion plasma. In this paper, we discuss a non-standard scheme of CTS measurements, which exploits strong refraction of probing and scattered microwave beams when reflecting from the cut-off layer in dense plasma. The scheme may be realized with the existing CTS diagnostic system at the Gas-Dynamic Trap (GDT) facility, a large open magnetic trap operating at Budker Institute (Novosibirsk, Russia). This requires a minor upgrade of the available hardware and essentially increases the range of plasma densities allowed for CTS measurements, as well as its sensitivity and spatial resolution. A detailed study of CTS efficiency for different geometries and plasma conditions at GDT is performed by means of an advanced numerical model that allows for an accurate description of non-Gaussian beam scattering in inhomogeneous plasma. To perform this task, we develop a quasi-optical theory of scattering, which itself may be of general interest.
Optimization of ultrasonic levitation bearing load characteristics based on rotor surface microstructure
Authors: Chen Guoda , Zhang Wei , Chen Zhaoshou , Tang Shenghao
Published: December 2023

Ultrasonic levitation bearings have lower load capacity and stiffness than other non-contact bearings, which restricts their practical use. This study proposes a method to improve the load characteristics of the bearings by adding microstructure on the rotor surface. The effects of different microstructure shapes, sizes, and quantities on the bearing load capacity and stiffness were investigated, and the mechanism of how the microstructures and their parameters affect the bearing static performance was revealed by analyzing the air film pressure field analysis of the bearing. Using the groove microstructure as an example, an optimization design was carried out to maximize the load capacity and stiffness of the ultrasonic levitation bearing, and the validity of this optimization was verified by the experiment.
Circle packing in arbitrary domains
Authors: Amore Paolo , de la Cruz Damian , Hernandez Valeria , Rincon Ian , Zarate Ulises
Published: December 2023

We describe an algorithm that allows one to find dense packing configurations of a number of congruent disks in arbitrary domains in two or more dimensions. We have applied it to a large class of two dimensional domains such as rectangles, ellipses, crosses, multiply connected domains and even to the cardioid. For some of the cases that we have studied, no previous result was available. The fundamental idea in our approach is the introduction of “image” disks, which allows one to work with a fixed container, thus lifting the limitations of the packing algorithms of Nurmela and Östergärd [Discrete Comput. Geom. 18(1), 111–120 (1997)], Amore and Morales [Discrete Comput. Geom. 70, 249–267 (2022)], and Amore [Phys. Fluids 35(2), 027130 (2023)]. We believe that the extension of our algorithm to three (or higher) dimensional containers (not considered here) can be done straightforwardly.
A minimization principle for incompressible fluid mechanics
Authors: Taha Haithem , Gonzalez Cody , Shorbagy Mohamed
Published: December 2023

Most variational principles in classical mechanics are based on the principle of least action, which is only a stationary principle. In contrast, Gauss' principle of least constraint is a true minimum principle. In this paper, we apply Gauss' principle to the mechanics of incompressible flows, thereby discovering the fundamental quantity that Nature minimizes in most flows encountered in everyday life. We show that the magnitude of the pressure gradient over the domain is minimum at every instant of time. We call it the principle of minimum pressure gradient (PMPG). It turns a fluid mechanics problem into a minimization one. We demonstrate this intriguing property by solving four classical problems in fluid mechanics using the PMPG without resorting to Navier–Stokes' equation. In some cases, the PMPG minimization approach is not any more efficient than solving Navier–Stokes'. However, in other cases, it is more insightful and efficient. In fact, the inviscid version of the PMPG allowed solving the long-standing problem of the aerohydrodynamic lift over smooth cylindrical shapes where Euler's equation fails to provide a unique answer. The PMPG transcends Navier–Stokes' equations in its applicability to non-Newtonian fluids with arbitrary constitutive relations and fluids subject to arbitrary forcing (e.g., electromagnetic).
Microfluidic viscometer using capillary pressure sensing
Authors: Kang Yang Jun
Published: December 2023

Blood viscosity is considered as a vital determinant of the efficiency of blood flow in blood-vessel networks. The coflowing method is considered as a promising technique for measuring blood viscosity. However, it requires two precise syringe pumps to supply two fluids (i.e., the reference fluid and blood), calibration in advance, and long waiting time for securing steady blood flow. To solve these problems, a single syringe pump is adopted to supply blood into a microfluidic device without requiring a reference fluid. Two key parameters—fluidic resistance and compliance coefficient—are suggested and obtained by analyzing the fluid velocities in a microfluidic channel and calculating the air pressure in the air compliance unit. Using a discrete fluidic circuit model, the pressure difference is analytically derived and utilized as the nonlinear regression formula. The two key parameters are then obtained through nonlinear regression analysis. According to experimental results, the air cavity and flow rate contribute to increasing the compliance coefficient. The fluidic resistance increases significantly at higher concentrations of glycerin solution ranging from 20% to 50%. The proposed method underestimates the values by approximately 27.5% compared with the previous method. Finally, the proposed method is adopted to detect the effects of hematocrit and red blood cell sedimentation in the driving syringe based on two vital parameters. Regarding the fluidic resistance, the normalized difference between the proposed and previous methods is less than 10%. Therefore, two key parameters can be considered as effective for quantitatively monitoring the hematocrit variation in blood flow. In conclusion, from a biomechanical perspective, the proposed method is highly promising for quantifying blood flow in a microfluidic channel.
Numerical investigation of the tip-vortex-induced ventilation formation mechanism for a surface-piercing hydrofoil
Authors: Zhi Yuchang , Huang Renfang , Qiu Rundi , Wang Yiwei , Sun Qun , Cai Shuting
Published: December 2023

Recent experiments have demonstrated that tip vortices can trigger the ventilation formation around a surface-piercing hydrofoil. However, the influence of this ventilation on transient flow structures and vortex evolution remains unresolved. This paper numerically investigates the tip-vortex-induced ventilation formation for a surface-piercing hydrofoil at a stalled yaw angle. The predicted unsteady ventilated cavities with tip vortices and pressure-side spray are in reasonable agreement with experimental observations. The ventilation formation process can be divided into three stages: base ventilation, tip-vortex ventilation, and suction-side ventilation. It is indicated that ventilation has a greater impact on the lift coefficient than the drag coefficient. The lift coefficient increases during the base ventilation and tip-vortex ventilation stages due to the expansion of the low-pressure stalled flow, but decreases in the suction-side ventilation stage because of the gradual replacement of this low-pressure region by an aerated cavity. Tip-leakage and tip-separation vortices initially exist independently at the hydrofoil tip, then expand and merge through air ventilation, ultimately forming a strongly stable tip vortex. Furthermore, ventilation promotes vortex generation, with the major contributors being the vortex stretching and baroclinic torque terms.
Topological antichiral edge states and one-way bulk states in patterned ferromagnetic thin films
Authors: Ke Shasha , Lou Wen-Kai , Li Yun-Mei , Chang Kai
Published: December 2023

The interfacial Dzyaloshinskii–Moriya interactions (iDMIs), occurring at the interfaces of the heavy metal and thin film, are anticipated to yield topologically nontrivial magnon modes, characterized by the Chern number. Based on the heterostructure consisting of a topologically trivial domain sandwiched between two nontrivial domains containing two distinct heavy metal dot arrays with opposite iDMI parameters, we present a theoretical proposal for the emergence of topological antichiral edge states and one-way bulk states, which possess remarkable immunity to backscattering and robustness against disorders. The features result in the generation of copropagating spin currents traveling at opposite edges, compensated by the counterpropagating spin currents confined within a large bulk area. Leveraging the greater tunability, flexibility, and extended transport areas associated with the one-way states, it becomes possible to design magnonic collimation devices. Our work offers us a way for observing intriguing physical phenomena and constructing low-dissipation magnonic devices.
Multi-scale analysis of seepage and erosion on collapse accumulation slope
Authors: Zhao Xiaoyi , Pei Xiangjun , Zhang Xiaochao , Huang Tiao , Zhu Jinyu
Published: December 2023

This study focused on the slope surface of debris deposits during the Luwei Sea landslide. Through seepage erosion tests, nuclear magnetic resonance and the coupling of computational fluid dynamics with the discrete element method, the seepage erosion of four representative areas on the slope surface was systematically studied at the macroscopic, mesoscopic and microscopic levels. The results showed that the particle size distribution has a significant impact on the seepage erosion characteristics. When the ratio of soil to rock was higher, soil–rock mixture showed stronger resistance to infiltration and soil protection during seepage erosion. The applied osmotic pressure also affected seepage erosion. However, when the osmotic pressure exceeded a certain critical value, pore blockage became the main mechanism of seepage erosion. Furthermore, a vegetation-based soil stabilization method involving geotechnical reconstruction and material soil stabilization in unvegetated areas was proposed, thereby promoting vegetation growth and enhancing slope stability. Our findings provided effective measures and a strategic theoretical basis for the rehabilitation of mudslide accumulation sites.
A numerical investigation into thermo-fluid characteristics of pulsating jet impingement on a dimpled surface
Authors: Mirikar Dnyanesh , Arumuru Venugopal , Yadav Harekrishna
Published: December 2023

A two-dimensional axisymmetric numerical model is employed to study the flow and heat transfer attributes of the pulsating air jet impingement on a dimpled surface. The results are compared with the steady jet impingement. The results are examined at a fixed Reynolds number of 5000, over a Strouhal number range of 0.1–0.5, and pulsation amplitude of 15% and 25% for three different nozzle-to-surface separations (z/d = 2, 6, and 10). The pulsation amplitude of 15% has a minor effect on heat transfer from the dimpled surface. However, at 25% pulsation amplitude, significant improvements in the heat transfer rates are obtained in many combinations of jet Strouhal number and jet surface spacing. The value of the optimum Strouhal number provides conditions for the maximum heat transfer rate, which varied with nozzle-to-surface separation distances. Combinations of higher separations and lower Strouhal numbers (and vice versa) produced optimum heat transfer among the cases considered in the present study. The maximum improvement (17.41%) in the average heat transfer over the steady jet was found at z/d = 10 for pulsation at St = 0.1, while at z/d = 6, St = 0.2 provides the highest heat transfer rate. It is urged that the vortices formed in pulse jet close to the natural frequency of vortex formation provide a conducive environment for the vortex growth and their existence, significantly affecting the jet entrainment, mixing, and jet spread, which eventually play the decisive factor in determining the overall heat transfer rates on the dimpled surface.
A perspective on nonlinear, microwave, and quantum photonics with Kerr microcombs
Authors: Chembo Yanne K. , Heidari Elham , Menyuk Curtis R.
Published: December 2023

Microresonator Kerr optical frequency combs currently constitute a well-established research area in integrated, nonlinear, and quantum photonics. These systems have found a plethora of technological applications, while serving as an excellent platform to investigate fundamental scientific topics such as light–matter interactions, pattern formation in driven-dissipative systems, or entangled twin-photon generation. We here provide a brief overview of the topic, highlight some of the most recent advances, and discuss a few of the main challenges ahead in this field.
The enrolment gap and the COVID-19 pandemic: an exploration of routinely collected primary care enrolment data from 2016 to 2023 in Aotearoa New Zealand
Authors: Pledger Megan , Mohan Nisa , Silwal Pushkar , Irurzun-Lopez Maite
Published: December 2023

Introduction For many countries, primary health care (PHC) serves as the gateway for individuals to access healthcare services. It has been shown to not only improve health but also health equity. To maximise this benefit, a substantial proportion of the population needs to be connected with PHC. The aim here was to assess the degree and evolution of enrolment in light of the coronavirus disease 2019 (COVID-19) pandemic in Aotearoa New Zealand. Methods We examined data on the enrolment of people in PHC organisations between 2016 and 2023. This analysis included breakdowns by sex, age groups, ethnicity, and socioeconomic deprivation levels. Poisson regression models were used to explore whether enrolment changed because of the COVID-19 pandemic. Results In 2016, Māori, young people and the most deprived had lower enrolment rates relative to their peers. Although young people’s enrolment rate increased over time, especially during the COVID-19 pandemic, the Māori enrolment rate declined, as did the rate for Pacific people, and those who were the most deprived. The groups who had increases in enrolment rates were those with the lowest levels of socioeconomic deprivation and those in the ‘Other’ ethnic category, predominantly made up of European New Zealanders. Conclusion Enrolment statistics reveal disparities across sociodemographic lines. The COVID-19 pandemic was associated with changed patterns of enrolment that appear to have consequences for population health.
Plasticity of intragraft alloreactive T cell clones in human gut correlates with transplant outcomes
Authors: Fu Jianing , Wang Zicheng , Martinez Mercedes , Obradovic Aleksandar , Jiao Wenyu , Frangaj Kristjana , Jones Rebecca , Guo Xinzheng V. , Zhang Ya , Kuo Wan-I , Ko Huaibin M. , Iuga Alina , Bay Muntnich Constanza , Prada Rey Adriana , Rogers Kortney , Zuber Julien , Ma Wenji , Miron Michelle , Farber Donna L. , Weiner Joshua , Kato Tomoaki , Shen Yufeng , Sykes Megan
Published: December 2023

The site of transition between tissue-resident memory (TRM) and circulating phenotypes of T cells is unknown. We integrated clonotype, alloreactivity, and gene expression profiles of graft-repopulating recipient T cells in the intestinal mucosa at the single-cell level after human intestinal transplantation. Host-versus-graft (HvG)–reactive T cells were mainly distributed to TRM, effector T (Teff)/TRM, and T follicular helper compartments. RNA velocity analysis demonstrated a trajectory from TRM to Teff/TRM clusters in association with rejection. By integrating pre- and post-transplantation (Tx) mixed lymphocyte reaction–determined alloreactive repertoires, we observed that pre-existing HvG-reactive T cells that demonstrated tolerance in the circulation were dominated by TRM profiles in quiescent allografts. Putative de novo HvG-reactive clones showed a transcriptional profile skewed to cytotoxic effectors in rejecting grafts. Inferred protein regulon network analysis revealed upstream regulators that accounted for the effector and tolerant T cell states. We demonstrate Teff/TRM interchangeability for individual T cell clones with known (allo)recognition in the human gut, providing novel insight into TRM biology.
Mass formulas for individual black holes in merging binaries
Authors: Ozkarsligil Zeynep Tugce , Tekin Bayram
Published: December 2023

We give formulas for individual black hole masses in a merger, by using Newtonian physics, in terms of the three measured quantities in the detector: the initial wave frequency f
1, the maximum detected frequency (chirp frequency) f
2, and the time elapse τ between these two frequencies. Newtonian gravity provides an excellent pedagogical tool to understand the basic features of gravitational wave observations, but it must be augmented with the assumption of gravitational radiation from General Relativity for accelerating masses as there is no gravitational wave Newtonian gravity. The simplest approach would be to consider a binary system of two non-spinning masses (two black holes) circling their common center of mass. All the computations can be done within Newtonian physics, but the General Relativistic formula for the power carried by gravitational waves is required in this scheme. It turns out there is a subtle point: for the consistency of this simple, yet pedagogical computation, taking the lowest order power formula from General Relativity leads to complex individual masses. Here we remedy this problem and suggest a way to write down an average power formula coming from perturbative General Relativity.
Surrogate-driven respiratory motion model for projection-resolved motion estimation and motion compensated cone-beam CT reconstruction from unsorted projection data
Authors: Huang Yuliang , Thielemans Kris , Price Gareth , McClelland Jamie R
Published: December 2023

Objective. As the most common solution to motion artefact for cone-beam CT (CBCT) in radiotherapy, 4DCBCT suffers from long acquisition time and phase sorting error. This issue could be addressed if the motion at each projection could be known, which is a severely ill-posed problem. This study aims to obtain the motion at each time point and motion-free image simultaneously from unsorted projection data of a standard 3DCBCT scan. Approach. Respiration surrogate signals were extracted by the Intensity Analysis method. A general framework was then deployed to fit a surrogate-driven motion model that characterized the relation between the motion and surrogate signals at each time point. Motion model fitting and motion compensated reconstruction were alternatively and iteratively performed. Stochastic subset gradient based method was used to significantly reduce the computation time. The performance of our method was comprehensively evaluated through digital phantom simulation and also validated on clinical scans from six patients. Results. For digital phantom experiments, motion models fitted with ground-truth or extracted surrogate signals both achieved a much lower motion estimation error and higher image quality, compared with non motion-compensated results.For the public SPARE Challenge datasets, more clear lung tissues and less blurry diaphragm could be seen in the motion compensated reconstruction, comparable to the benchmark 4DCBCT images but with a higher temporal resolution. Similar results were observed for two real clinical 3DCBCT scans. Significance. The motion compensated reconstructions and motion models produced by our method will have direct clinical benefit by providing more accurate estimates of the delivered dose and ultimately facilitating more accurate radiotherapy treatments for lung cancer patients.