bluuebunny/crossref_metadata_2025 huggingface dataset:
Searching for Hα-emitting sources in the gaps of five transitional disks
Authors: Huélamo N. , Chauvin G. , Mendigutía I. , Whelan E. , Alcalá J. M. , Cugno G. , Schmid H. M. , de Gregorio-Monsalvo I. , Zurlo A. , Barrado D. , Benisty M. , Quanz S. P. , Bouy H. , Montesinos B. , Beletsky Y. , Szulagyi J.
Published: October 2022

Context. (Pre-)Transitional disks show gaps and cavities that can be related to ongoing planet formation. According to theory, young embedded planets can accrete material from the circumplanetary and circumstellar disks and can be detected using accretion tracers, such as the Hα emission line.

Aims. We aim to detect accreting protoplanets within the cavities of five (pre-)transitional disks through adaptive-optics(AO)-assisted spectral angular differential imaging in the optical regime.

Methods. We performed simultaneous AO observations in the Hα line and the adjacent continuum using the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) with the Zurich Imaging Polarimeter (ZIMPOL) at the Very Large Telescope (VLT). We combined spectral and angular differential imaging techniques to increase the contrast in the innermost regions close to the star and search for the signature of young accreting protoplanets.

Results. The reduced images show no clear Hα point source around any of the targets. We report the presence of faint Hα emission around TW Hya and HD163296: while the former is most probably an artifact related to a spike, the nature of the latter remains unclear. The spectral and angular differential images yield contrasts of 6–8 magnitudes at ~100 mas from the central stars, except in the case of LkCa15, with values of ~3 mag. We used the contrast curves to estimate average upper limits to the Hα line luminosity of LHα ~ 5 × 10-6 L⊙ at separations ≥200 mas for TW Hya, RXJ1615, and T Cha, while for HD163296 and LkCa15 we derive values of ~3 × 10−5 L⊙. We estimated upper limits to the accretion luminosity of potential protoplanets, obtaining that planetary models provide an average value of Lacc ~ 10−4 L⊙ at 200 mas, which is about two orders of magnitude higher than the Lacc estimated from the extrapolation of the LHα - Lacc stellar relationship.

Conclusions. When considering all the objects observed with SPHERE/ZIMPOL in the Hα line, 5 in this work and 13 from the literature, we can explain the lack of protoplanet detections by a combination of factors, such as a majority of low-mass, low-accreting planets; potential episodic accretion; significant extinction from the circumstellar and circumplanetary disks; and the fact that the contrast is less favorable at separations of smaller than 100 mas, where giant planets are more likely to form.
A systematic study of super-Eddington layers in the envelopes of massive stars
Authors: Agrawal Poojan , Stevenson Simon , Szécsi Dorottya , Hurley Jarrod
Published: October 2022

Context. The proximity to the Eddington luminosity has been attributed as the cause of several observed effects in massive stars. Computationally, if the luminosity carried through radiation exceeds the local Eddington luminosity in the low-density envelopes of massive stars, it can result in numerical difficulties, inhibiting further computation of stellar models. This problem is exacerbated by the fact that very few massive stars are observed beyond the Humphreys-Davidson limit, the same region in the Hertzsprung-Russell diagram where the aforementioned numerical issues relating to the Eddington luminosity occur in stellar models.

Aims. One-dimensional stellar evolution codes have to use pragmatic solutions to evolve massive stars through this computationally difficult phase. In this work, we quantify the impact of these solutions on the evolutionary properties of massive stars.

Methods. We used the stellar evolution code MESA with commonly used input parameters for massive stellar models to compute the evolution of stars in the initial mass range of 10–110 M⊙ at one-tenth of solar metallicity.

Results. We find that numerical difficulties in stellar models with initial masses greater than or equal to 30 M⊙ cause these models to fail before the end of core helium burning. Recomputing these models using the same physical inputs but three different pragmatic solutions to treat the numerical instability, we find that the maximum radial expansion achieved by stars can vary by up to 2000 R⊙, while the remnant mass of the stars can vary by up to 14 M⊙ between the sets. These differences can have implications on studies such as binary population synthesis.
On the Machining of Joint Implant UHMWPE Inserts
Authors: Piska Miroslav , Urbancova Katerina
Published: October 2022

The modern orthopaedic implants for applications in hips, knees, shoulders, and spines are composed of hard metal alloys or ceramics. The tribo-logical sub-component is composed of soft materials with good tribological properties – e.g. UHMWPE (Ultra High Molecule Weight Polyethylene). The UHMWPE implants need to be machined into their final shape after the polymerization and consolidation into a blank profile or near-net shaped implant.

So machining is a crucial technology that can generate an accurate and precise shape of the implant that should comply with the joints’ function. However, the machining technology can affect the topography and integrity of the surface, and its resistance to wear. The technology, cutting tools, and cutting conditions can impact the physical and mechanical properties of the entire implant, limiting its life span and creating a need to be replaced.

The basic machining technologies are turning and milling (each can be used as roughing or finishing). There are many ways to machine these surfaces. Many problems such as low rigidity of the product, poor thermal properties of the material, high melt viscosities, and sticking of the material to the cutting edge (production of built-up edges) have been solved. UHMWPE can be damaged by excessive heat, feed rate, cutting force, and tool micro-geometry. The shapes and dimensions for the customized implants vary broadly for the humans this complicates the machining technology. No standard programs can be used repeatedly so each joint must be designed and produced individually. However, it results in the longer implant life and a better comfort of patients.
Getting started procedure of a NC machine simplified by the use of a mixed-reality training scenario
Authors: Seitier Philippe , Gilles Patrick , Boudier Valérie , Galaup Michel , Lagarrigue Pierre
Published: October 2022

To allow increased manufacturing quality and integration in Industry 4.0, machines have become increasingly complex, resulting in increasingly difficult operating procedures and therefore a longer and more expensive operatortraining period. Moreover, to be competitive in a global market where competition is sometimes distorted by local aid, European companies must be innovative and flexible. They must therefore be able to count on competent and responsive staff capable of adapting to the various workstations. The initial and continuous training of personnel is therefore a crucial need today. The arrival on the market of AR and VR technologies makes it possible to imagine new training models generally taking into account the technical possibilities, without rethinking the educational scenarios. The work carried out in this study consists of offering novice users a set of educational scenarios and an augmented reality device for handling a 3D printer. A first work carried out on a small group of students tests the autonomy of the users with this new material. A second experiment carried out on 80 first-year engineering school students made it possible to quantify usability using a standardized SUS questionnaire. The results show that the level of usability varies from good to excellent, regardless of whether the user has used a VR headset before. They also validate the transmission of technical skills. To obtain this result, the observed criterion is the effective printing of a part in an autonomous manner. The global work in progress aims at providing relevant training scenarios for the use of machine tools.
Anästhesie bei Kindern und Jugendlichen mit Behinderung
Authors: Laschat Michael , Kaufmann Jost , Wappler Frank
Published: October 2022

Die sichere anästhesiologische Versorgung von Kindern und Jugendlichen mit körperlichen oder geistigen Behinderungen ist zumeist zeitaufwendig und anspruchsvoll. In diesem Beitrag wollen
wir auf Besonderheiten in der perioperativen Versorgung von behinderten Kindern und Jugendlichen hinweisen. Auf die Probleme bei der Anästhesie von Kindern mit Autismus-Spektrum-Störung,
infantiler Zerebralparese und Trisomie 21 gehen wir im Anschluss näher ein.
Den ethischen Kompass im Blick – Werteaspekte in der Digitalisierung
Authors: Kemper Claudia
Published: October 2022

Digitale Interventionen bieten viele Chancen, können aber auch einen ethischen Schaden mit sich bringen, indem sie zum Beispiel die Selbstbestimmung einschränken oder Ungerechtigkeiten in der Versorgung verstärken. Daher ist der Umgang mit Wertefragen unumgänglich, möchte man den ethischen Kompass in der Gesundheitsversorgung nicht aus dem Blick verlieren.
Die richtige Dosis finden – Motiviert trainieren trotz Schmerzen
Authors: Pfeiffer Fabian
Published: October 2022

Wenn Menschen mit chronischen Schmerzen therapeutische Ratschläge ignorieren und körperlich inaktiv bleiben, kann das ganz unterschiedliche Gründe haben. Erst die Evaluation der individuellen Schmerzsituation entlarvt die tatsächlichen Hindernisse für ein Training. Eine patientenzentrierte Zielsetzung, das Berücksichtigen von Präferenzen und eine individuelle Übungsauswahl motivieren die Patient*innen und ebnen so den Weg zu einem aktiveren Lebensstil.
Lewis Acid Promoted Homodimerization of Styrene Diols: An Efficient Approach toward 2-Phenylnaphthalenes
Authors: Hazra Chinmoy Kumar , Mahato Rina , Khan Jabir , Tyagi Aparna
Published: October 2022

We report a straightforward, metal-free, efficient protocol for the synthesis of 2-phenylnaphthalenes from 1-phenylethane-1,2-diols under mild conditions. In this strategy, 1,1,1,3,3,3-hexafluoro-2-propanol is used as a solvent that stabilizes the reaction intermediate. An in situ IR experiment revealed that the reaction proceeds through the formation of phenylacetaldehyde followed by a [4+2] Diels–Alder reaction. Several control experiments were performed to gain mechanistic insights into the reaction.
Antihypertensive Medication Use before and during Pregnancy and the Risk of Severe Maternal Morbidity in Individuals with Prepregnancy Hypertension
Authors: Bane Shalmali , Wall-Wieler Elizabeth , Druzin Maurice L. , Carmichael Suzan L.
Published: October 2022

Objective Our objective is to examine severe maternal morbidity (SMM) and patterns of antihypertensive medication use before and during pregnancy among individuals with chronic hypertension.

Study Design We examined 11,759 pregnancies resulting in a live birth or stillbirth to individuals with chronic hypertension and one or more antihypertensive prescription 6 months before pregnancy (Optum, 2007–17). We examined whether study outcomes were associated with the use of medication as compared to no use during pregnancy. In addition, patterns of medication use based on the Food and Drug Administration guidance and literature were evaluated. Medication use was divided into prepregnancy and during pregnancy use and classified as pregnancy recommended (PR) or not pregnancy recommended (nPR) or no medication use. SMM was defined per the Centers for Disease Control and Prevention definition of 21 indicators. Risk ratios (RR) reflecting the association of SMM with the use of antihypertensive medications were computed using modified Poisson regression with robust standard errors and adjusted for maternal age, education, and birth year.

Results Overall, 83% of individuals filled an antihypertensive prescription during pregnancy and 6.3% experienced SMM. The majority of individuals with a prescription prior to pregnancy had a prescription for the same medication in pregnancy. Individuals with any versus no medication use in pregnancy had increased adjusted RR (aRR) of SMM (1.18, 95% confidence interval [CI]: 0.96–1.44). Compared to the use of PR medications before and during pregnancy, aRRs were 1.42 (95% CI: 1.18–1.69, 12.4% of sample) for nPR use before and during pregnancy, 1.52 (1.23–1.86; 12.4%) for nPR (before) and PR (during) use, and 2.67 (1.73–4.15) for PR and nPR use. Patterns with no medication use during pregnancy were not statistically significant.

Conclusion Pattern of antihypertensive medication use before and during pregnancy may be associated with an elevated risk of SMM. Further research is required to elucidate whether this association is related to the severity of hypertension, medication effectiveness, or suboptimal quality of care.

Key Points
Effect of phase change in the layered VSx nanosheets for investigation of dielectric function and optical properties at the wavelength range of 10–20 μm
Authors: Parishani Marziyeh , Nadafan Marzieh , Malekfar Rasoul
Published: October 2022

In this study, we synthesized VSx transition metal chalcogenides by the hydrothermal method and changed some parameters (reaction time, synthesis temperature, and adding surfactant) in the synthesis process. In this work, the structure of samples has been analyzed (by x-ray diffraction, ultraviolet–visible, Fourier-transform infrared, field-emission scanning electron microscopy). The vanadium sulfide structure phase altered from VS4 to VS2 by increasing the time and temperature of the reaction. Based on Kramers–Kronig equations, the effect of changing synthesis parameters and sheet dimensions on optical and dielectric parameters was investigated. Different components of the complex refractive index and complex dielectric function are increased by decreasing sheet dimensions. Also, the position of transversal and longitudinal optical modes is shifted to lower wavenumbers by increasing sheet dimensions. Moreover, the real part of the dielectric function alters from negative to positive by sheet dimension’s alteration. This study demonstrates the great potential of vanadium sulfide compounds for optoelectronics applications.
Reprogrammable control of electromagnetic spectra based on time-coding plasmonic metamaterials
Authors: Zhang Le Peng , Zhang Hao Chi , Zhang Jingjing , Niu Ling Yun , He Pei Hang , Wei Cunyue , Tang Wenxuan , Cui Tie Jun
Published: October 2022

Programming electromagnetic spectra have become key technology affecting the development of the information industry, arousing widespread interest of researchers. Here, we propose a route to realize a programmable spectrum based on time-coding spoof surface plasmon polaritons (SSPPs) to implement the customized harmonic generations and amplitude manipulations. The proposed time-coding SSPPs are experimentally demonstrated to flexibly control both frequencies and amplitudes of the harmonics, providing the possibility of reprogrammable outputs of different spectra. In addition, two kinds of improved time-coding SSPP structures are presented, which can be applied to realize reprogrammable spectra without the fundamental component and with customized asymmetric spectra.
Macroscopic quantum electrodynamics approach to multichromophoric excitation energy transfer. I. Formalism
Authors: Wang Siwei , Chuang Yi-Ting , Hsu Liang-Yan
Published: October 2022

In this study, we develop a theory of multichromophoric excitation energy transfer (MC-EET) in the framework of macroscopic quantum electrodynamics. The theory we present is general for studying the interplay between energy transfer and fluorescence in the presence of arbitrary inhomogeneous, dispersive, and absorbing media. The dynamical equations of MC-EET, including energy-transfer kernels and fluorescence kernels, allow us to describe the combined effects of molecular vibrations and photonic environments on excitation energy transfer. To demonstrate the universality of the MC-EET theory, we show that under specific conditions, the MC-EET theory can be converted to three representative theories. First, under the Markov approximation, we derive an explicit Förster-type expression for plasmon-coupled resonance energy transfer [Hsu et al., J. Phys. Chem. Lett. 8, 2357 (2017)] from the MC-EET theory. In addition, the MC-EET theory also provides a parameter-free formula to estimate transition dipole–dipole interactions mediated by photonic environments. Second, we generalize the theory of multichromophoric Förster resonance energy transfer [Jang et al., Phys. Rev. Lett. 92, 218301 (2004)] to include the effects of retardation and dielectric environments. Third, for molecules weakly coupled with photonic modes, the MC-EET theory recovers the previous main result in Chance–Prock–Silbey classical fluorescence theory [Chance et al., J. Chem. Phys. 60, 2744 (1974)]. This study opens a promising direction for exploring light–matter interactions in multichromophoric systems with possible applications in the exciton migration in metal–organic framework materials and organic photovoltaic devices.
Anomalous resistivity upturn in the van der Waals ferromagnet Fe5GeTe2
Authors: Huang Yalei , Yao Xinyu , Qi Fangyi , Shen Weihao , Cao Guixin
Published: October 2022

FenGeTe2 (n = 3, 4, and 5) has recently attracted increasing attention due to its two-dimensional van der Waals characteristic and high temperature ferromagnetism, which makes promises for spintronic devices. A Fe(1) split site is an important structural characteristic of Fe5GeTe2, which makes it very different from other FenGeTe2 (n = 3 and 4) systems. The local atomic disorder and short-range order can be induced by the split site. In this work, high-quality van der Waals ferromagnet Fe5GeTe2 single crystals were grown to study low-temperature transport properties. We found a resistivity upturn below 10 K. The temperature and magnetic field dependence of the resistivity are in good agreement with a combination of the theory of disorder-enhanced three-dimensional electron–electron and single-channel Kondo effect. The Kondo effect exists only at low magnetic fields B<3 T, while electron–electron interaction dominates the appearance for the low-temperature resistivity upturn. We believe that the enhanced three-dimensional electron–electron interaction in this system is induced by the local atomic structural disorder due to the split site of Fe(1). Our results indicate that the split site of Fe plays an important role for the exceptional transport properties.
Thermodynamic limits of atmospheric water harvesting with temperature-dependent adsorption
Authors: Li Adela Chenyang , Zhang Lenan , Zhong Yang , Li Xiangyu , El Fil Bachir , Fulvio Pasquale F. , Walton Krista S. , Wang Evelyn N.
Published: October 2022

Adsorption-based atmospheric water harvesting (AWH) has vast potential for addressing global water shortage. Despite innovations in adsorbent materials, fundamental understanding of the physical processes involved in the AWH cycle and how material properties impact the theoretical limits of AWH is lacking. Here, we develop a generalized thermodynamic framework to elucidate the interplay between adsorbent properties and operating conditions for optimal AWH performance. Our analysis considers the temperature dependence of adsorption, which is critical but has largely been overlooked in past work. Using metal-organic framework (MOF) as an example, we show that the peak energy efficiencies of single-stage and dual-stage AWH devices, after considering temperature-dependent adsorption, increased by 30% and 100%, respectively, compared with previous studies. Moreover, in contrast to common understanding, we show that the adsorption enthalpy of MOFs can also be optimized to further improve the peak energy efficiency by 40%. This work bridges an important knowledge gap between adsorbent materials development and device design, providing insight toward high-performance adsorption-based AWH technologies.
Flow-induced vibration of a circular cylinder with an attached elastic plate of high aspect ratio
Authors: Manjunathan Sujyesh Aanandh , Borazjani Iman
Published: October 2022

The flow-induced transverse vibration of a cylinder (diameter D*) with an attached flexible and elastic plate of high aspect ratio to its leeward side is investigated numerically at a low Reynolds number of 150 for a range of reduced velocities (Ur) using an in-house developed fluid solver based on curvilinear immersed boundary method strongly coupled with an open-source finite element-based structural solver. It was observed that an attached elastic plate of width B=B*/D*=0.1 and length L=L*/D*=1 suppresses large vibrations of the cylinder, but one with length L = 2, contrary to previous studies, amplifies vibrations up to five times of an isolated cylinder. Three regimes were observed: vortex-induced vibration (VIV), suppression, and galloping. In VIV regime for 3≤Ur≤7, lock-in was observed where the vortex shedding frequency from the plate-cylinder system was seen to slightly increase relative to that of static cylinder–plate system to match with the natural frequency of the cylinder and the plate. In this regime, the deformations of the elastic plate were large (max. 91% of L) and in high modes (up to fifth mode), leading to new vortex patterns. The transverse displacement of the cylinder–plate system was found to reach nearly twice of an isolated cylinder in this regime. For 7<Ur≤9, the cylinder–plate system was pushed into suppression regime, wherein its displacement was nullified because of lack of vorticity interaction and out-of-phase deformation. Beyond Ur = 9, the cylinder–plate system vibrated in the galloping regime, wherein it shed and generated forces as an asymmetric body creating an angle of attack with the incoming flow. The primary mode of deformation of the elastic plate progressively increased from second mode to third mode in galloping regime, and the transverse displacement of cylinder showed a linear increase with the increase in reduced velocity until Ur = 18. The vibration amplitude of the cylinder was higher in the galloping regime, but the vibrations of the plate were more intense (higher amplitude and mode) in the VIV regime. New vortex patterns were observed in the VIV and galloping regimes ranging from 2S mode till 2T mode including all the vortex pattern between them like 2S, 2P, 2Q, and P + T modes, which are reported for the first time.
An asymptotic expansion method vs a self-similar solution for convective heat transfer in rotating cone-disk systems
Authors: Shevchuk Igor V.
Published: October 2022

This paper compares an asymptotic expansion method and a self-similar solution for modeling Couette flow and convective heat transfer in a conical gap at small conicity angles up to 4°. The cases of rotation of a cone with a stationary disk and rotation of a disk with a stationary cone are considered. The self-similar system of equations provides the best agreement with experiments compared to the asymptotic expansion method. In any case, both methods are applicable only to conicity taper angles up to 4°, while at large conicity angles, the calculation results become significantly inaccurate. Calculations also showed that, at small conicity angles, convective heat transfer can be modeled using the self-similar energy equation in the boundary-layer approximation without considering radial heat conduction. In this study, analytical solutions were also obtained for limiting cases of a stationary fluid in a gap at small conicity angles without and with allowance for radial heat conduction.
Two-dimensional Darcy–Bénard convection evolving in Fourier space
Authors: Tyvand Peder A. , Molstad Lars
Published: October 2022

Nonlinear transient convection in a porous rectangle heated from below is studied by an analytically based method. Fourier series for the temperature and streamfunction are applied, where each Fourier coefficient evolves in time according to a coupled set of ordinary differential equations. The mathematical method can be considered as a recursive nonlinear mapping in Fourier space from a given state at a time t to an updated state at time t + dt, with an infinitesimal time increment. This nonlinear evolution in Fourier space requires normal-mode compatible boundary conditions along the entire boundary. Each Fourier coefficient gets three contributions during its updating in time: (i) one decay term due to thermal diffusion, governed by linear theory; (ii) one growth term due to buoyancy, governed by linear theory; and (iii) quadratic nonlinearities from the convection term in the heat equation, involving all pairwise interactions between the Fourier modes. We present numerical computations with a standard Runge–Kutta method, with Rayleigh numbers up to ten times the well-known critical value 4π2. Our plots are produced with Fourier series truncated to include 15 normal modes in both the horizontal and vertical directions. For validation of our method, we present tables for the Nusselt number of steady convection, with a higher number (up to 20) of normal modes included in the truncated system of equations. Our computations of transient nonlinear convection lead to steady states. A final steady state is not unique for a given geometry, but depends on the initial state and the Rayleigh number. This ambiguity of steady states is depicted by a hysteresis loop. The Malkus hypothesis of maximal heat transfer is put into perspective. This hypothesis does not pick a preferred cell width, but it nevertheless constrains the hysteresis loop.
A new design for energy-saving volutes in centrifugal pumps
Authors: Wang Tao , Yu He , Fang Yujian , Xiang Ru , Kan Nengqi , Yan Jing
Published: October 2022

Geometrical structures and operating performance of volutes used in centrifugal pumps are assessed in cross sections. By a volute, we mean the wetted part surrounding the impeller in a pump that converts the kinetic energy of water into potential energy. It is important to develop improved design principles and approaches for volutes to reduce hydraulic loss and increase the efficiency of pumps. However, when designing volutes, pump designers often neglect a key factor related to pump efficiency, namely, the energy loss due to the friction at the volute sidewall is directly proportional to the wetted perimeter of the cross section. In this paper, we show that the length of the wetted perimeter of the cross section is mathematically proportional to the friction loss in the volute. In addition, we present the design principles and calculation process to minimize the wetted perimeters of two kinds of cross section based on the velocity coefficient method using the same statistical data. The structures and shapes of the new cross sections are completely different from those of traditional volutes. Moreover, two different volutes with different cross sections are numerically investigated using a verified computational fluid dynamics technique. Both the head and the efficiency of the pump with the new volute are higher than those of a conventional pump under all working conditions. This paper provides a new design approach for the energy-saving volutes of centrifugal pumps.
Lagrangian wavelet analysis of turbulence modulation in particle–liquid mixing flows
Authors: Savari Chiya , Barigou Mostafa
Published: October 2022

A new experimental–theoretical framework has been developed to investigate turbulence and turbulence modulation in a two-phase multicomponent particle–liquid flow in a mechanically agitated vessel. A discrete wavelet transform is used to decompose long-term three-dimensional Lagrangian trajectories of flow phases, acquired by a technique of positron emission particle tracking, into their deterministic and stochastic sub-trajectories. The sub-trajectories are then used to construct the different-scale local velocity and turbulent kinetic energy (TKE) fields of the two-phase flow. The effects of the particle size and size distribution mode (mono, binary, and polydisperse), particle concentration, impeller agitation speed, and pumping mode on turbulence intensity are investigated. Amongst these factors, the particle size, impeller pumping mode, and particle size distribution mode have a significant impact on liquid turbulence. The presence of large particles enhances liquid turbulence and broadens the region in the vessel characterized by high local TKE values. Results also show that a down-pumping pitched-blade turbine generates significantly greater local maxima in the TKE field, which tend to be more localized in the impeller discharge stream. In addition, binary or polydisperse suspensions containing higher fractions of larger particles produce higher turbulence intensities in the carrier phase. The detailed information obtained on the turbulence intensity is crucial for better understanding of the dynamics of particle–liquid flows inside mixing vessels to aid the rational design of these units.
Rumen microbial genomics: from cells to genes (and back to cells)
Authors: Popova Milka , Fakih Ibrahim , Forano Evelyne , Siegel Anne , Muñoz-Tamayo Rafael , Morgavi Diego P.
Published: October 2022

The rumen harbours countless bacteria, archaea, ciliated protozoa, fungi and viruses: various microorganisms that have established multiplicity of relationships to efficiently digest complex plant fibres and polysaccharides to produce volatile fatty acids (VFAs), microbial proteins and vitamins, essentials for the host’s health, growth and performances. Recent studies using omics-based techniques have revealed that changes in rumen microbiota are associated with changes in ruminants’ production and health parameters such as feed efficiency, methane yield, milk composition and ruminal acidity. However, traditionally, rumen microbes were unveiled using anaerobic culture-based techniques, which are at the origin of most of the basic concepts and understanding of the rumen functioning. Isolating and culturing microbes is frequently more difficult and time-consuming and requires more training than molecular techniques, which explains why culture seems to be abandoned in favour of sequencing. Microbial cultures enable the study of substrate preferences and product output, essential growth requirements, biocide production and susceptibilities; obtaining a pure culture also enables genome sequencing of these strains. We propose here, after a brief report of published rumen isolates, a comprehensive review of current advances in molecular methods to identify novel rumen microbes and discuss how culturing and mathematics could enhance our understanding of rumen microbiology.
Nutritional and therapeutic significance of non-bovine milk for human health applications
Authors: Verma Mahima , Rout Pramod Kumar
Published: October 2022

Non-bovine milk(s) and their dairy products are showing a rise in market demand as they are gaining consumers’ attention. Non-bovine milk serves as an important source of nutrition and sustenance for populations in difficult climatic and geographical regions. Milk from different non-bovine species is known to have several nutritional and therapeutic values. Thus, it becomes important to study the composition and constituents of non-bovine milk(s) and their products with respect to microbial load and post-translational modifications of proteins in human health applications. The cheeses and fermented milk products produced from non-bovine milk are widely distributed across a large variety of climatic and geographical areas. Non-bovine milk proteomics is being analysed to know the role of milk proteins and peptides in metabolism, immune regulation and disease pathways for application in nutraceutical and drug development. Therapeutic proteins for human use are being produced in the “goat model” as a bio-reactor. The biological potential of milk is manifold as it is transformed into various products with specific nutritive and health-promoting values. Therefore, the purpose of this article is to review different aspects of non-bovine milk(s) in nutrition, traditional dairy product, milk proteome, bioactive peptides, microbiota and antimicrobial resistance due to intensive production for diverse applications and better economic impact in different regions.
Magnetic energy in quasistatic systems
Authors: Redinz José Arnaldo
Published: October 2022

Magnetic energy is often presented solely as an energy stored by an inductor or in a magnetic field, in contrast to electrostatic energy which is introduced through the concepts of electric interaction between point-charges. Quasistatics, with its many applications in everyday life and important pedagogical appeal, has many similarities to statics and can allow a discussion of magnetic energy in terms which reinforces the parallel between magnetostatics and electrostatics. With this goal in mind, we consider two simple examples in textbooks involving a parallel plate capacitor and a flattened solenoid, to discuss the interplay between the work of external forces, the work of the electric interaction forces between the charges and currents and the electric and magnetic energies stored in these devices.
Wet bulk micromachining characteristics of Si{110} in NaOH-based solution
Authors: Purohit S , Swarnalatha V , Pandey A K , Sharma R K , Pal P
Published: October 2022

Silicon wet bulk micromachining is an extensively used technique in microelectromechanical systems (MEMS) to fabricate variety of microstructures. It utilizes low-cost etchants and suitable for batch process that made it popular for industrial production. The etch rate and the undercutting at convex corner significantly affect the productivity. In wet anisotropic etching-based micromachining, Si{110} wafer is employed to fabricate unique shape geometries such as the microstructures with vertical sidewalls. In this research, we have investigated the etching characteristics of Si{110} in 10 M sodium hydroxide without and with addition of hydroxylamine (NH2OH). The main objective of the present work is to improve the etch rate and the undercutting at convex corners. Average surface roughness (R
a), etch depth, and undercutting length are measured using a 3D scanning laser microscope. Surface morphology of the etched Si{110} surface is examined using a scanning electron microscope. The incorporation of NH2OH significantly improves the etch rate and the corner undercutting, which are useful to enhance the productivity. Additionally, the effect of etchant age on the etch rate and other etching characteristics are investigated. The etch rate of silicon and the undercutting at convex corners decrease with etchant aging. The results presented in this paper are very useful to scientists and engineers who use silicon wet anisotropic etching to fabricate MEMS structures using bulk micromachining. Moreover, it has great potential to promote the application of wet etching in MEMS.
MNBr (M = Mo, Cr, V) monolayer: two-dimensional ferromagnetic half-metallic materials with high Curie temperature
Authors: Li Fei , Wan Wenhui , Liu Yong , Ge Yanfeng
Published: October 2022

Two-dimensional (2D) intrinsic magnetic materials with a high Curie temperature (T

C
) and 100% spin-polarization are highly desirable for creating spintronic devices. In this work, the electronic structure and intrinsic magnetism of MNBr (M = Mo, Cr, V) monolayers are predicted by using first-principles calculations. The results show that MNBr (M = Mo, Cr, V) monolayers with GGA + U functionals are intrinsic ferromagnetic (FM) half-metals with wide half-metallic gaps. Monte Carlo simulations based on the Heisenberg model are used to estimate the T

C
of MoNBr, CrNBr and VNBr, which are 402 K, 673 K, and 120 K, respectively. The magnetic performances are significantly modulated by strain and carrier doping. Our results show that the intrinsic half-metals with a high T

C
and controllable magnetic properties make MNBr (M = Mo, Cr, V) monolayers potential for spintronic applications.
Method for extracting the equivalent admittance from time-varying metasurfaces and its application to self-tuned spatiotemporal wave manipulation
Authors: Aminulloh Fathnan Ashif , Homma Haruki , Sugiura Shinya , Wakatsuchi Hiroki
Published: October 2022

With their self-tuned time-varying responses, waveform-selective metasurfaces embedded with nonlinear electronics have shown fascinating applications, including distinguishing different electromagnetic waves depending on the pulse width (PW). However, thus far they have only been realized with a spatially homogeneous scattering profile. Here, by modeling a metasurface as time-varying admittance sheets, we provide an analytical calculation method to predict the metasurface time-domain responses. This allows derivation of design specifications in the form of equivalent sheet admittance, which is useful in synthesizing a metasurface with spatiotemporal control, such as to realize a metasurface with prescribed time-dependent diffraction characteristics. As an example, based on the proposed equivalent admittance sheet modeling, we synthesize a waveform-selective Fresnel zone plate with variable focal length depending on the incoming PW. The proposed synthesis method for PW-dependent metasurfaces may be extended to designing metasurfaces with more complex spatiotemporal wave manipulation, benefiting applications such as sensing, wireless communications and signal processing.
Impact of deposition temperature on crystalline quality, oxygen vacancy, defect modulations and hetero-interfacial properties of RF sputtered deposited Ga2O3 thin films on Si substrate
Authors: Saha Rajib , Bhowmick Sangita , Mishra Madhuri , Sengupta Ankita , Chattopadhyay Sanatan , Chakrabarti Subhananda
Published: October 2022

In the current work, thin film (∼55 nm) of n-type Ga2O3 (n-Ga2O3) is deposited on silicon (p-Si) substrate by using radio-frequency (RF) sputtering technique with systematic substrate temperature variations (room temperature to 700 °C). The structural, optical properties and chemical states of elements of the deposited films are observed to depend significantly on the deposition temperatures. The chemical composition and oxidation states, optical properties, defect states and structural quality of the deposited films are investigated in detail by employing x-ray photoelectron spectroscopy, energy dispersive x-ray, spectroscopic ellipsometry, Raman, photoluminescence and atomic force microscopy images. X-ray diffraction result reveals a polycrystalline nature of monoclinic β-phase of Ga2O3 with (403) dominant plane. The work functions are calculated from the ultraviolet photo-electron spectroscopy for all the deposited films and Ga2O3/Si heterojunction properties are investigated by using current–voltage (I–V) and capacitance–voltage (C–V) measurements. Among all the fabricated heterojunctions, 600 °C deposited Ga2O3 film exhibits superior performance in terms of energy bandgap, work function, refractive index, barrier height, rectification ratio and effective carrier concentrations. The current transport mechanism is analysed using the appropriate energy band diagram of Ga2O3 and Si. Therefore, the study suggests that 600 °C deposition temperatures is the optimum temperature for developing a high quality Ga2O3 thin film on Si by using RF sputtering technique and corresponding Ga2O3 thin film/Si heterojunction can be a potential candidate for developing several electronic and optoelectronic devices.
Localization of light in 2D photonic Moiré superlattices
Authors: Yang He , Zhai Jianing , Huo Shuang , Wang Zhan , Chen Deli , Sun Xiaohong
Published: October 2022

In this paper, monolayer photonic Moiré superlattices (PMSs) are constructed by superposing two periodic sublattices with square primitive cells and tunable twist angles. The sublattices are designed by interfering four umbrella-like beams. Light localization properties and physical flat-band effects of PMSs are studied by solving the Schrödinger equation in the periodic potentials. We have investigated the influence of interference angle and twist angle of sublattices on the localization of light and physical flat bands, and demonstrated that PMSs have physical flat bands and strong light localization properties when the twist angle is less than 5°, while the interference angle does not affect the flat-bands and localization properties. Our work provides a new research idea for manipulating spatial light fields and processing light information.
Affecting the structure of skyrmions using ferromagnetic nanodisks with inhomogeneous properties: switching skyrmion helicity and polarity
Authors: Silva R L , Silva R C , Pereira A R
Published: October 2022

The topological stability of skyrmions is an important element for using these objects in new technologies such as skyrmionics, spintronics, and so on. Indeed, this kind of stability keeps a skyrmion’s structure as unbending, shielding the information that, by chance, it could carry. On the other hand, a controlled manipulation of skyrmion configuration could be an extra ingredient for technological applications. It is not an easy task and, particularly, the control of skyrmion polarity and chirality (for Bloch-type) and helicity (for Néel-type) may be important in this direction. Here, we investigate the skyrmion oscillatory motion in a hybrid nanodisk by using atomistic spin dynamics simulations. If a skyrmion is made to oscillate in a disk formed by two different materials with opposite Dzyaloshinskii–Moriya interactions (

D

1

=
−

D

2

), then its helicity experiences an inversion. Nonetheless, if the skyrmion oscillations occur in a homogeneous disk submitted to opposite magnetic fields in distinct regions (for instance, semi-disks 1 and 2), the skyrmion polarity and helicity suffer an inversion. Such skyrmionic-oscillators could provide a dynamical degree of freedom, yielding new functionalities to skyrmion-based logic devices.
Prediction for high superconducting ternary hydrides below megabar pressure
Authors: Sun Yao , Sun Shuai , Zhong Xin , Liu Hanyu
Published: October 2022

The recent findings of high-temperature hydrides ushered a new era of superconductivity research under high pressure. However, the stable pressure for these remarkable hydrides remains extremely high. In this work, we performed the extensive simulations on a series of hydrides with the prototype structure of UH8 and UH7. Our results indicate several compounds possess superconducting critical temperature (T
c) above liquid nitrogen temperature below 100 GPa, such as CeBeH8 and ThBeH8 that are dynamical stable with a T
c of 201 K at 30 GPa and a T
c of 98 K at 10 GPa, respectively. Further formation enthalpy calculations suggest that thermodynamical stable pressure of CeBeH8 and ThBeH8 compounds is above 50 GPa and 88 GPa with respect to binary compounds and solid elements. Moreover, we also found that ThBeH7 could be dynamically stable down to 20 GPa with a T
c of 70 K. Our further simulations suggested this newly predicted ThBeH7 is thermodynamically stable above pressure of 33 GPa with respect to binary compounds and solid elements. The present results shed light on future design and discovery of high-temperature superconductor at moderate pressure.
Topological magnons in the honeycomb-kagome lattice
Authors: Li Kangkang
Published: October 2022

Materials with magnon Hall effect have potential applications in the field of spintronics and magnonics. The experimental observations of the magnon Hall effect in three-dimensional pyrochlore ferromagnets and two-dimensional kagome ferromagnets inspired the search for topological magnons in various lattice structures. The honeycomb-kagome (HK) lattice (also known as the edge-centered honeycomb lattice) can be seen as the combination of the honeycomb and kagome lattices. Hence, the Dzyaloshinskii–Moriya (DM) interaction is allowed and topological magnons are expected in the HK lattice, as the cases in the honeycomb and the kagome lattices alone. Here, we study the topological magnons in the HK lattice by calculating its band structure, Chern number, edge states and thermal Hall conductivity. It is shown that there are rich topological phases and phase transitions with the tuning of the model parameters. The finite thermal Hall conductivity induced by the DM interaction also has interesting behaviors, which are related to the topological phase transitions.
New magnetorheological engine mount with controllable stiffness characteristics towards improved driving stability and ride comfort
Authors: Yang Jian , Sun Shuaishuai , Ezani Saeid , Gong Ning , Deng Lei , Zhang Shiwu , Li Weihua
Published: October 2022

Engine mount is an important subassembly installed between the chassis and the engine. Its importance is mainly reflected by its capability of protecting the car body from the engine-induced vibrations. The current semi-active engine mount works to mitigate the vibration by changing its damping, while the property of variable stiffness can further suppress the vibrations by reducing the vibration transmissibility. Therefore, this paper developed a new magnetorheological engine mount which can change its stiffness to shift the natural frequency of the mounting system away from the excitation frequency so that resonance can be avoided when the engine is starting. The stiffness controllability also meets the stiffness design conflict between vibration isolation requirement and engine stability requirement when the cars drive on rough roads. The characterization test has verified its field-dependent properties that the effective stiffness has increased by 80.65% and the equivalent damping coefficient has increased by 26.85% as the applied current increases from 0 A to 1.5 A. Then a vibration isolation test was performed to evaluate the mounting system’s vibration reduction performance using a commercial internal combustion engine. The test results verified that the new magnetorheological engine mount under the semi-active control algorithm named Short Time Fourier Transformation is much better at suppressing the engine-induced vibrations than under passive control. And finally, a stability test was conducted and it verified that the new magnetorheological engine mount under Short Time Fourier Transformation control algorithm (semi-active control) performed better stability than the passive control. These experimental results indicate that this new magnetorheological engine mount is highly effective in isolating the engine-induced vibrations and keeping the driving stability.
The jetting process and spreading characteristics of the power-law fluids for material jetting process
Authors: Sun Chaochao , Chu Xiangcheng , Chen Jiaqi , Chen Di , Ren Jingzhi , Yuan Songmei
Published: October 2022

Materials jetting, known as one of the 3D printing technologies, is widely applied in microelectronics packaging, biology and ceramic 3D printing due to its ability to print multi-materials by drop-on-demand. However, most of the materials are power-law fluids in 3D printing applications, the generation of satellites during the jetting process and droplet spreading characteristics are unclear and they have a great effect on the quality of the printout. In this paper, a common electromechanical and fluid-solid coupling model of the jet dispenser and observation platform of the jetting process are established. This modeling method is also suitable for other needle-driven jet dispensers. A commercial UV resin is adopted to study the jetting process of power-law fluid. To reveal the mechanism of satellite generation, the effects of input signals (rising time and falling time) on the dynamic characteristics of the needle and the jetting process are analyzed. On the basis thereof, the effectiveness of the optimal control parameters is demonstrated to eliminate satellites. In addition, the simulation and experimental results show that the falling time and fluid pressure can be controlled to adjust the spreading diameter and height of the droplet. Subsequently, the minimum line width of 0.276 mm is successfully printed with a nozzle of 0.07 mm.