bluuebunny/crossref_metadata_2025 huggingface dataset:
Discovery of a hot post-AGB star in Galactic globular cluster E3
Authors: Kumar R. , Moharana A. , Piridi S. , Pradhan A. C. , Hełminiak K. G. , Ikonnikova N. , Dodin A. , Szczerba R. , Giersz M. , Ojha D. K. , Samal M. R.
Published: April 2024

We report a new hot post-asymptotic giant branch (PAGB) star in the Galactic globular cluster (GC) E3, which is one of the first of the identified PAGB stars in a GC to show a binary signature. The star stands out as the brightest source in E3 in the Astrosat/UVIT images. We confirmed its membership with the cluster E3 using Gaia DR3 kinematics and parallax measurements. We supplemented the photometric observations with radial velocities (RVs) from high-resolution spectroscopic observations at two epochs and with ground- and space-based photometric observations from 0.13 μm to 22 μm. We find that the RVs vary over ∼6 km s−1 between the two epochs. This is an indication of the star being in a binary orbit. A simulation of possible binary systems with the observed RVs suggests a binary period of either 39.12 days or 17.83 days with mass ratio q ≥ 1.0. The [Fe/H] derived using the high-resolution spectra is ∼−0.7 dex, which closely matches the cluster metallicity. The spectroscopic and photometric measurements suggest Teff and logg of the star as 17 500 ± 1000 K and 2.37 ± 0.20 dex, respectively. Various PAGB evolutionary tracks on the Hertzsprung–Russell (H–R) diagram suggest a current mass of the star in the range 0.51–0.55 M⊙. The star is enriched with C and O abundances, showing similar CNO abundances compared to the other PAGB stars in GCs with the evidence of the third dredge-up on the AGB phase.
Parsec-scale cosmic-ray ionisation rate in Orion
Authors: Socci A. , Sabatini G. , Padovani M. , Bovino S. , Hacar A.
Published: April 2024

Context. Cosmic rays are a key component of the interstellar medium because they regulate the dynamics and chemical processes in the densest and coldest regions of molecular clouds. Still, the cosmic-ray ionisation rate of H2 (ζH2ion) is one of the most debated parameters characterising molecular clouds because of the uncertainties in the adopted chemical networks and analysis techniques.

Aims. This work aims to homogeneously estimate the ζH2ion at parsec scales towards the Orion Molecular Clouds OMC-2 and OMC-3. We explore the change in ζH2ion across a whole star-forming region by probing a range of column densities that has never been explored before. The significant increase in statistics obtained by studying an entire region allows us to place stronger constraints on the range of ζH2ion values and exploit its connection with the physical properties of the interstellar medium.

Methods. The most recent ζH2ion estimates are based on o-H2D+, which is a direct product of the interaction between cosmic rays and H2 in cold clouds. Since observations of o-H2D+ are challenging, we proxy its abundance through CO depletion by employing C18O (2–1) observations towards OMC-2 and OMC-3, taking advantage of the existing correlation between the two parameters. Using additional observations of HCO+ (1–0) and DCO+ (3–2), we determine the deuteration fraction, and we finally derive the map of ζH2ion in these two regions.

Results. The C18O depletion correlates with both the total column density of H2 and the N2H+ emission across OMC-2 and OMC-3. The obtained depletion factors and deuteration fractions are consistent with previous values obtained in low- and high-mass star-forming regions. These two parameters additionally show a positive correlation in the coldest fields of our maps. We derive cosmic-ray ionisation rates of ζH2ion ~ 5 × 10-18-10-16s-1. These values agree well with previous estimates based on o-H2D+ observations. The ζH2ion also shows a functional dependence on the column density of H2 across a full order of magnitude (~1022–1023 cm−2). The estimated values of ζH2ion decrease overall for increasing N(H2), as predicted by theoretical models.

Conclusions. The results delivered by our approach are comparable with theoretical predictions and previous independent studies. This confirms the robustness of the analytical framework and promotes CO depletion as a viable proxy of o-H2D+. We also explore the main limitations of the method by varying the physical size of the gas crossed by the cosmic rays (i.e. the path length). By employing a path length obtained from low-resolution observations, we recover values of the ζH2ion that are well below any existing theoretical and observational prediction. This discrepancy highlights the need for interferometric observations in order to reliably constrain the ζH2ion at parsec scales as well.
Extended high-ionization [Mg IV] emission tracing widespread shocks in starbursts seen by JWST/NIRSpec
Authors: Pereira-Santaella Miguel , García-Bernete Ismael , González-Alfonso Eduardo , Alonso-Herrero Almudena , Colina Luis , García-Burillo Santiago , Rigopoulou Dimitra , Arribas Santiago , Perna Michele
Published: April 2024

We report the detection of extended (> 0.5–1 kpc) high-ionization [Mg IV] 4.487 μm (80 eV) emission in four local luminous infrared galaxies observed with JWST/NIRSpec. Excluding the nucleus and outflow of the Type 1 active galactic nucleus (AGN) in the sample, we find that the [Mg IV] luminosity is well correlated with that of H recombination lines, which mainly trace star-forming clumps in these objects, and that the [Ar VI] 4.530 μm (75 eV), usually seen in AGN, is undetected. On 100–400 pc scales, the [Mg IV] line profiles are broader (σ([Mg IV]) = 90 ± 25 km s−1) and shifted (Δv up to ±50 km s−1) compared to those of the H recombination lines and lower ionization transitions (e.g., σ(Hu-12) = 57 ± 15 km s−1). The [Mg IV] kinematics follow the large-scale rotating velocity field of these galaxies, and the broad [Mg IV] profiles are compatible with the broad wings detected in the H recombination lines. Based on these observational results, extended highly ionized gas more turbulent than the ambient interstellar medium, possibly a result of ionizing shocks associated with star formation, is the most likely origin of the [Mg IV] emission. We also computed new grids of photoionization and shock models to investigate where the [Mg IV] line originates. Shocks with velocities of 100–130 km s−1 reproduce the observed line ratios and the [Mg IV] luminosity agrees with that expected from the mechanical energy released by supernove (SNe) in these regions. Therefore, these models support shocks induced by SNe as the origin of the [Mg IV] line. Future studies on the stellar feedback from SNe will benefit from the [Mg IV] line that is little affected by obscuration and, in the absence of an AGN, can only be produced by shocks due to its high ionization-potential.
The use of differentials to increase the efficiency of orienting robotic devices of agricultural equipment
Authors: Litiuga Nickita , Podchasov Evgeniy
Published: April 2024

Robots are used in modern agricultural equipment. There are several types of robot designs: articulated robots, delta robots, sсara robots and others. Almost every robot has in its design an orienting device, designed to orient the tool, used by the robot in space. Orienting devices differ from each other by different structural diagrams of transmission mechanisms and types of links, functioning in the mechanisms. All orienting devices are united by a design feature, which consists in the fact, that in order to rotate the tool around the axis of any kinematic pair, which is the degree of mobility of the orienting device, it is necessary to rotate several electric drives. If you rotate with one electric drive, the tool will make a spherical movement. The reason for this effect is that the kinematic chains, through which rotation is transmitted from the electric drive to the tool, intersect with each other. The use of differentials in the design will allow the tool to rotate around one axis by one electric drive, which gives some advantages in motion control. The article describes the design features and the principle of operation of the orienting device with differentials.
Unmanned aerial systems for biological plant protection based on UAV type CE-20
Authors: Kovalev Igor , Kovalev Dmitry , Podoplelova Valeria , Borovinsky Dmitry
Published: April 2024

The article presents an analysis of the use of UAVs of the CE-20 type as part of unmanned aerial systems for biological plant protection. The relevance of the study is determined by the intensive development of modern unmanned technologies used to combat insect pests and plant diseases. The proposed analysis of modern practice of using UAVs of the CE-20 type for biological plant protection will reveal the relationship of technical characteristics with agrotechnological methods. This will provide effective technical support for unmanned aerial systems applications in precision agriculture. It is important to consider that the characteristics of the UAVs used significantly influence the process of spraying fertilizers and pesticides. The article analyzes the previously obtained results of test flights of the CE- 20 of the Chinese company Wuxi Hanhe Aviation Technology. Testing was carried out taking into account a given field cultivation strip, on which the effective spray width of fertilizers and pesticides was determined and studied. The obtained droplet deposition coefficients of variation showed good deposition uniformity and penetration rate. It is shown that optimization of UAV parameters must be combined with agronomic requirements based on the choice of crop types, growth period, pest and disease characteristics, and environmental conditions.
Raising calves using cold methods at an early age
Authors: Sattarov Narmurod , Shavazov Kadirjon , Yunusov Rustem , Suvanov Anvar , Yangiboev Abdimalik , Kholbutaev Ilyosjon , Atanasov Atanas
Published: April 2024

The article discusses the results of scientific and economic experience carried out in the winter - in the spring period, which showed that when raising newborns and calves in dispensary houses in the open air, it is necessary to strictly comply with a number of favorable conditions; calving of cows should take place in stalls: newborn calves in must be kept in a place with their mothers for 24 hours; Calves should be provided with more careful care and their own - temporary feeding, daily addition of dry straw bedding. Young animals raised in the open air, subject to all these specified conditions, are significantly less susceptible to gastrointestinal diseases, grow better and use high-quality roughage more.
Results of theoretical and experimental researches about determination the corn seed separator sieve parameters of the corn-thresher machine
Authors: Fozilov Golibjon , Islam Rafiq , Akhmedov Alisher , Nulloev Ulugbek , Shodmonov Shakhboz , Alimova Zebo , Yuldoshev Sharofiddin
Published: April 2024

For use in Uzbek fields, a novel sort of corn-thresher machine was created and tested. To separate the cornhusks from the pods, the peeler bars were positioned symmetrically on the cornthresher machine’s rotor surface. However, around 4-5 percent grain was going out from machine’s outlet for pith and husk when the corn thresher was tested experimentally. It was decided to create the sieve in order to save losing grain from outlet. We observed the sieve theoretically to determine the optimal parameters for the corn thresher. The corn thresher machine was equipped with specific grain separator sieve in front of outlet. Some experimental researches were carried out to define optimal parameters of the sieve for developed corn-thresher machine. Minimal amount of grain and impurities in the grain that coming from outlet is ensured during the technological process of the machine. The corn-thresher machine uses the least amount of metal and energy while functioning qualitatively. The corn-thresher machine weighs 400 kg, uses 5 KW of power, and can process 4600 kg of grain per hour in pure time.
The current state of soybean production and its size-mass indicators in the conditions of Uzbekistan
Authors: Umirov Abdigappar , Kodirova Mukaddas , Karshieva Bogdagul , Turayev Khumoyidin , Mukumova Feruza , Kodirov Bakhtiyor , Eshchanova Guzal
Published: April 2024

Soybeans are a valuable crop, yet in Uzbekistan, the cultivation area is small, covering approximately 150,000 hectares. The main reasons are the lack of suitable soybean varieties for the local climate, water scarcity, and competition for land with other crops. Harvesting is a critical process, and in Uzbekistan, combine harvesters are commonly used. To prevent damage during harvesting, it is essential to understand the size-mass indicators of soybeans grown in Uzbekistan. Experiments have shown that the height of soybeans during harvesting varies from an average of 63 to 99 cm, depending on the variety and cultivation methods. The average lower stem diameter ranges from 4.1 to 7.1 mm, and the pod height varies from 15 cm for the Oyjamol and Amigo varieties to 6 cm for the Selekta variety. The height of the plant is 21.0 to 29.8 pods per bush, and the grain-to-stem ratio is 1:1.1 to 1:1.8. These indicators are crucial for adjusting the working parts of harvesters to optimal operating modes, minimizing damage during harvesting. The lack of suitable soybean varieties for the local climate and water scarcity are significant challenges that must be addressed to increase the cultivation area of soybeans in Uzbekistan.
Green infrastructure development as a factor of Moscow metropolis sustainable development
Authors: Gurieva Lira , Kurnosova Tatyana
Published: April 2024

The research is aimed at improving the sustainable development of cities, which focuses on the systemic goal setting of environmental development tasks, social policy and economic responsibility. The development of green infrastructure has been among the sustainable development goals of many cities around the world since the early 2000s. The study showed that the modern understanding of green infrastructure in Russia is still not widespread, which creates problems for the sustainable development of Russian cities in the future, since the implemented greening programs generally reflect a more simplified and fragmented meaning of the city’s green infrastructure. It has been established that the situation in Russia has begun to change over the past few years: new scientific, methodological and practical approaches to the development of green infrastructure in Russian cities have been developed, leading state and public institutions presented ratings reflecting the ideology of the development of green infrastructure in cities within the framework of the principles of sustainable development. Based on the method of comparative and statistical analysis, the article identifies the features of the development of green infrastructure in Moscow, shows its advantages and problems, and suggests directions for its sustainable development based on innovative approaches to vertical gardening.
The evolution of a negotiated territorial development approach
Authors: Groppo Paolo , Mora Hernan , Ravera Federica , Bicchieri Marianna , Carranza Francisco , de Gaetano Marco , Tarrason David , d’Errico Marco
Published: April 2024

The need for further discussion on territoriality in the context of rural development, driven by the political forces of globalization and the economic and social transformations within nations, comes as no surprise. It arises from the necessity to adapt methodologies, instruments, and activities to meet the new demands imposed by these changes and their unintended consequences. Ultimately, it fosters a fresh perspective on territorial issues, actively involving rural populations in the formulation of novel development outlooks. This article retraces a journey embarked upon over two decades ago by a group of individuals operating under the auspices of the FAO Rural Development Division. Their aim was to transition from traditional rural development approaches towards an evolving paradigm centered on dialogue, negotiation, and territorial collaboration. A multitude of factors converged to lay the foundation for the initial discussions surrounding the concept of territory. This included a consideration of ecological and gender dimensions, which placed heightened emphasis on power dynamics and prompted a reflective analysis of the conventional role of “experts." This shift redirected focus away from being mere proponents of technical solutions and toward embracing a new role as facilitators of social processes. Ultimately, the critical question at hand revolves around the very concept of “development", originally formulated and imposed by the Western world at the conclusion of the Second World War. According to the authors, it necessitates a profound revaluation.
Non-equilibrium orbital angular momentum for orbitronics
Authors: Go Dongwook , Mokrousov Yuriy , Kläui Mathias
Published: April 2024

Efficient manipulation of magnetization by electrical current is a key aim in spintronics. The state-of-the-art theories and experiments in spintronics show that harnessing non-equilibrium orbital angular momentum can significantly enhance the efficiency due to novel torques. Devices are based on environment-friendly materials, which has been difficult to achieve by the mechanisms based on spin only, and this has also kickstarted a new emerging field of research: orbitronics.
Weak error expansion of a numerical scheme with rejection for singular Langevin process
Authors: Journel Lucas
Published: April 2024

We show expansion à la Talay–Tubaro of a numerical scheme with rejection for the Langevin process in the case of a singular potential. In order to achieve this, we provide estimates on the associated semi-group of the process. The class of admissible potentials includes the Lennard-Jones interaction with confinement, which is an important potential in molecular dynamics and served as the primary motivation for this study.
Retrospective Analysis of Bicanalicular Lacrimal Silicone Tube Intubation in Patients with Congenital Nasolacrimal Duct Obstruction: A Long-term Follow-up Study
Authors: Lahme Larissa , Eter Nicole , Zimmermann Julian Alexander , Storp Jens Julian , Merté Ralph-Laurent
Published: April 2024

Congenital nasolacrimal duct obstruction (CNLDO) is the most common cause of epiphora in the first year of life. In addition to conservative therapy, there are several invasive methods available. The aim of this retrospective study was to conduct a long-term follow-up of bicanalicular lacrimal duct intubation as the primary intervention in a large cohort of patients with CNLDO. The electronic medical records of 487 patients with CNLDO who underwent bicanalicular tube intubation were reviewed. To determine the long-term outcomes, a telephone interview was conducted. A total of 328 eyes of 235 patients were included in the study. The median average follow-up period was 6.67 (5.58 – 8.67) years. At the time of the survey, 218 patients (92.8%) were symptom free. Mean patient satisfaction with surgical outcome was 10/10. To our knowledge, this study provides the longest follow-up of the largest patient cohort in the literature consisting of patients who underwent probing with
bicanalicular lacrimal silicone tube intubation as a primary intervention for CNLDO. This study showed a high long-term postoperative success rate, with high postoperative satisfaction, few complications, and a low need for reintervention.
Effects of Exercise-Induced Changes in Myokine Expression on the
Tumor Microenvironment
Authors: Gunasekara Nadira , Clauss Dorothea , Bloch Wilhelm
Published: April 2024

In this narrative review, we summarize the direct and indirect effects that
myokines have on the tumor microenvironment. We took studies of various cancer
types and species into account. Systematic reviews and meta-analyses that
matched the search terms were also considered. We searched databases for six
months. As a narrative approach was chosen, no data was analyzed or reanalyzed.
The goal of this narrative review is to create an overview on the topic to
identify research gaps and answer the questions as to whether myokine expression
may be relevant in cancer research in regard to the tumor microenvironment. Six
commonly known myokines were chosen. We found strong links between the influence
exercise has on interleukin-6, oncostatin M, secreted protein acidic and rich in
cysteine, and irisin in the context of tumor progression and inhibition via
interactions with the tumor microenvironment. It became clear that the effects
of myokines on the tumor microenvironment can vary and contribute to disease
progression or regression. Interactions among myokines and immune cells must
also be considered and require further investigation. To date, no study has
shown a clear connection, while multiple studies suggest further investigation
of the topic, similar to the effects of exercise on myokine expression.
Vade Mecum in ERCP, a roadmap to success: Tips from experts for excelling in ERCP
Authors: Teles de Campos Sara , Arvanitaki Marianna , Boskoski Ivo , Deviere Jacques
Published: April 2024

Background and study aims Training in endoscopic retrograde cholangiopancreatography (ERCP) is operator-dependent and traditionally, the apprenticeship model, in which experts are considered to be role models, has been adopted for it. The aim of this study was to develop a practical guide compiling tips from experts to help guide trainees to succeed in ERCP.

Methods A web-based survey was created to understand the professional development of ERCP experts, the investments they made, the obstacles they overcame, and the quotes that guided their professional life. ERCP experts worldwide were invited to participate.

Results Fifty-three experts (of 71; 74.6%) from 24 countries answered the survey. Experts started ERCP training early (average age 31 years; range, 24–52 years) and it often was combined with training for endoscopic ultrasound. A long training period (average 21 months; range, 3–120 months) was needed to achieve competence, frequently in another department, and it was commonly complemented with research in the field (76.5%). “Time and practice” were the most worthwhile investments they made to achieve success. “Sports” were an area outside endoscopy frequently considered to be important to acquire the skills necessary to excel in ERCP. “Lack of dedicated time for training” and “peer competition” were the biggest obstacles the experts faced. Several pieces of advice were given to the experts, such as to be resilient, careful, patient, responsible, and hard-working. “Personal life” was mentioned as an undeniably crucial factor for achieving long-term success that should not be forgotten.

Conclusions This survey is the first to provide insight regarding the professional trajectory of renowned ERCP experts worldwide, providing valuable recommendations to help trainees excel in ERCP.
Photocatalytic Annulation of Enaminones with Thioureas for the Synthesis of 2-Aminothiazoles via Tandem C–S and C–N Bond Formation
Authors: Wan Changfeng , Wan Jie-Ping , Huang Qihui
Published: April 2024

Visible-light photocatalytic reactions between enaminones and thioureas leading to thiazole products have been achieved. The annulation process consists of tandem C–S and C–N bond formation by running reactions under air atmosphere at ambient temperature. Broad substrate tolerance of the sustainable protocol has been verified by the practical synthesis of divergent thiazoles with both monocyclic and fused cyclic structures.
Partial Sacrectomy in the Management of Sacral Chordoma: Case Report and Literature Review
Authors: Santos Nicoly Augusta da Silva Quezada dos , Maximiano Mariana Letícia de Bastos , Cortez Paulo Rogério
Published: April 2024

Chordomas are rare neoplasms of low to intermediate grades, which arise from ectopic remnants of notochordal tissue, presenting a slow growth pattern and locally aggressive behavior. Due to their insidious course, the diagnosis is late, requiring immediate therapeutic intervention. The main prognostic factor is total surgical resection with wide margins. This therapeutic objective is only achieved in 40% to 55.6% of the cases, since chordoma tends to present an aggressive behavior, invading adjacent tissues and neurovascular structures. Currently, the main challenge of sacrectomy is to balance a wide resection with the preservation of the neurological function of the patient. Despite cases of successful gross total resection, local recurrence is an inevitable reality, and the overall survival is relatively low. The indication of adjuvant therapies is not well stablished in the literature, since the response to radiotherapy is not satisfactory for these tumors. The aim of the present study is to present a report the case of a patient with sacral chordoma (SC) who underwent partial sacrectomy and to carry out a brief review of the literature on sacrococcygeal chordomas.
Clinical Assessment of a Lateral Epicondylar Anatomical Plate for the Stabilization of Humeral Condylar Fractures in Dogs
Authors: Jones Rebecca L. , Tomlinson Andrew W. , Barnes Duncan M. , Hood Rebecca S. , McClement Jamie P. , Ogden Daniel M. , Owen Mark A. , Onyett Jeremy R. , Walton Myles B.
Published: April 2024

Objective To report the use of a Lateral Epicondylar Anatomical Plate for the management of humeral condylar fractures (HCF) in dogs.

Study Design Medical records of dogs with HCF stabilized using the Lateral Epicondylar Anatomical Plate at six UK veterinary referral centres between April 2018 and February 2021 were reviewed. Long-term follow-up (>6 months) was obtained via owner questionnaire, which incorporated the Liverpool Osteoarthritis in Dogs clinical metrology instrument.

Results Sixty-two HCF were treated in 61 dogs (44 lateral condylar fractures [LCF] and 18 intracondylar (T/Y) fractures [ICF]). Fifty-one dogs were Spaniels or Spaniel crossbreeds. Intraoperative contouring of the plate was required for one dog—a French Bulldog. Postoperative complications occurred in 14/42 LCF and 6/18 ICF; overall there were 14 minor, 8 major, and 2 catastrophic complications. On final follow-up imaging, there was evidence of partial or complete osseous continuity of the condylar part of the fracture 32/53 HCF (24/39 LCF and 8/14 ICF) and lateral epicondylar part of the fracture in 53/53 HCF (39/39 LCF and 14/14 ICF). At final reexamination, 20/28 dogs with LCF and 5/13 dogs with ICF were not lame and the remaining dogs demonstrated mild lameness. According to the owner questionnaire, 17/17 dogs with LCF and 8/10 dogs with ICF returned to full limb use and median Liverpool Osteoarthritis in Dogs scores were 2/52 for LCF and 6.5/52 for ICF.

Conclusion The Lateral Epicondylar Anatomical Plate can be used successfully for the surgical stabilization of HCF in dogs.
Perpetrators in multimodal media discourse: a case study of personalization in images from The Telegraph
Authors: Shurma Svitlana
Published: April 2024

The article deals with the visual and linguistic representation of alleged perpetrators through personalization in news reporting from The Telegraph’s online media platform. The analysis shows how visual message, along with verbal labelling in the text, represent different groups of alleged perpetrators as more or less ‘dangerous’ in news reports. Agency is analyzed through a focus on the lens range and its influence on perceived social distance, the angle of the shot and its role in the understanding of social relations, as well as the direction of an alleged perpetrator’s gaze in images as a way of social interaction with the viewer. The photos of alleged perpetrators appear in The Telegraph with the aim of informing the public about the danger these individuals pose, as well as legitimizing the actions of law enforcement institutions. It appears that verbal and visual identification of these individuals is done with the intention of ‘excluding’ the most dangerous social actors, such as ‘murderers’, from ingroups.
Self-consistent charge transport model with ionization for the alphie plasma thruster
Authors: Gonzalez J. , Conde L. , Donoso J. M.
Published: April 2024

The Alternative Low-Power Hybrid Ion Engine (alphie) is a new technology for space propulsion based on plasma. Its distinct characteristic is the counterflow of charges (ions and electrons) passing through its two-grid system. This means that electrons coming from an external cathode are accelerated toward the ionization chamber, in which a neutral gas (typically Ar) is injected. The strong magnetic field therein confines these electrons, which ionize and exchange energy with the propellant gas. Thus, the operation of alphie is strongly affected by the electrons coming from the external cathode and their collisions with the neutral atoms. This work studies the counterflow employing a particle-in-cell simulation of ions and electrons passing through a single hole as a function of the electron cathode currents (Ice) and potential drops between grids (VAC). Transparency of the grid system to ions and electrons and the ion current extracted by the grid system are studied under sweeps of these two parameters. The number of ionization events by each high-energy electron entering the ionization chamber is evaluated using a physical model based on the gas density and the cross section for ionization. These new ions are then extracted by the same electric field that accelerates the electrons inward. Thus, simulations are self-consistent, since the ionizing electron flow from the external cathode drives the ion outflow at the exit section of the two-grid system. The electrical transparency of the two-grid system to ions and electrons, related to the axial charge currents, is also studied under sweeps of aforementioned operation parameters. This new way to deal with ionizations can be useful to study other plasma thrusters in which electrons for ionization come from an external cathode without modeling the complex structure of the ionization chamber.
Elastic and inelastic phonon scattering effects on thermal conductance across Au/graphene/Au interface
Authors: Chen Weiyu , Zhou Quan , Han Quan , Liu Chenhan , Jiang Xinchi , Gu Yunfeng , Wu Gensheng , Zhang Yan , Wei Zhiyong , Chen Yunfei
Published: April 2024

Heat dissipation from graphene devices is predominantly limited by heat conduction across the metal contacts with complex phonon scattering. In this work, the effects of elastic and inelastic phonon scattering on the interfacial thermal conductance (ITC) across the Au/graphene/Au interface are studied using both atomistic Green's function (AGF) and reverse non-equilibrium molecular dynamics methods. The results show that the contribution of inelastic phonon scattering to the ITC increases with the enhancement of interfacial bonding strength. Moreover, the overlap of the vibrational density of states across the interface shows that the coupling between the Au layer (adjacent to the Au/graphene interface) and graphene's out-of-plane modes plays the dominant role in ITC across the Au/graphene interface. By comparing the transmission functions calculated with AGF and spectral heat current decomposition methods, the inelastic phonon scattering process facilitates phonon transmission in the lower and higher frequency range but hinders phonon transmission in the intermediate frequency range. It is expected that this study can contribute to a better understanding of the thermal conduction mechanism across the metal/graphene interface, providing guidance for thermal management and heat conduction optimization of graphene in microelectronic devices.
A high temperature engine materials test facility
Authors: Shelton Prabha H. , Wadley Haydn N. G.
Published: April 2024

Gas turbine engines subject materials to extreme conditions. Their high temperature materials and co-developed coatings must survive combustion gas temperatures currently approaching 1800 °C, large thermal gradients, severe thermal shock, and static and fatigue inducing applied stresses, all the while operating in highly reactive, high-pressure, high-speed combustion gas flows containing significant partial pressures of water vapor, oxygen, and other reactive species for many tens of thousands of hours. We describe the design and development of a test facility for the study of materials under individual and combinations of test parameters similar to those experienced within legacy and future engines. A hydraulic load frame capable of applying static or cyclic tension-compression stresses up to 400 MPa to flat-dog bone-shaped test specimens is integrated within an environmental test chamber capable of sustaining gas pressures from 0.1 to 1.2 MPa (1–12 atm). An adjustable 0.1–2 kW power CO2 laser whose 10.6 µm wavelength radiation is strongly absorbed by ceramic coating materials is used to heat sample surfaces to temperatures of 1800 °C and above, while rear surface air jet cooling establishes through-thickness thermal gradients. Rapid laser heating in conjunction with transiently applied front and/or rear-side air cooling is used to create hot or cold thermal shock effects. This is accompanied by the impingement of a high pressure (up to 1.3 MPa) reactive gas jet upon the sample with speeds up to 300 m/s by preheating dry air, mixing it with steam to the desired humidity, heating to 850 °C, and then expanding it through a converging nozzle. Thermal imaging pyrometers measure specimen front and back surface temperature fields, while environmental test chamber view ports permit digital image correlation and strain mapping.
On the enhancement and suppression of turbulent wall pressure by the Large Eddy BreakUp devices
Authors: Chong T. P. , Muhammad C.
Published: April 2024

An experimental study is presented on the application of Large Eddy BreakUp (LEBU) on a flat plate as an aeroacoustics noise source-targeting device to perturb the wall pressure fluctuations of a turbulent boundary layer. When interacting with a LEBU wake, the wall pressure spectra can establish a self-similar behavior against s′, which is a normalized separation distance between the LEBU's trailing edge and the targeted location for aeroacoustics noise source mitigation. It is found that s′>3 is needed to achieve an overall reduction in the wall pressure fluctuations. The fundamental mechanism by which the LEBU can reduce the wall pressure fluctuation is investigated by studying the spatio-temporal evolution of turbulent spots. When the emanated LEBU wake is interacted with the outer part of turbulent spot, the shielding effect can always inhibit the turbulent fluids ejection from the spot's leading edge. However, incursion of the high momentum fluids wall-sweeping event at the spot's trailing edge can only be effectively prevented when s′>3.
Resonant decay of kinetic Alfvén waves and implication on spectral cascading
Authors: Shen Kexun , Cheng Zhiwen , Qiu Zhiyong
Published: April 2024

A general equation describing the resonant nonlinear mode-coupling among kinetic Alfvén waves (KAWs) is derived using nonlinear gyrokinetic theory, which can be applied to study the potentially strong spectral energy transfer of KAWs. As a first application, the parametric decay of a pump KAW into two sideband KAWs is studied, with particular emphasis on cascading in the perpendicular wavenumber. It is found that, for the “co-propagating” cases with all three KAWs propagating in the same direction along the equilibrium magnetic field line, it exhibits a dual cascading character in the perpendicular wavenumber space; while for the “counter-propagating” cases with one sideband propagating in the opposite direction with respect to the pump wave, it instead, can exhibit both dual and inverse cascading behaviors. Furthermore, the implications of these findings on shear Alfvén waves regarding instability, nonlinear saturation, and charged particle transport in fusion plasmas are also discussed.
Development of a platform for experimental and computational studies of magnetic and radiative effects on astrophysically relevant jets at OMEGA
Authors: Rigon G. , Stoeckl C. , Johnson T. M. , Katz J. , Peebles J. , Li C. K.
Published: April 2024

Accurate modeling of astrophysical jets is critical for understanding accretion systems and their impact on the interstellar medium. While astronomical observations can validate models, they have limitations. Controlled laboratory experiments offer a complementary approach for qualitative and quantitative demonstration. Laser experiments offer a complementary approach. This article introduces a new platform on the OMEGA laser facility for high-velocity (1500 kms−1), high-aspect-ratio (∼36) jet creation with strong cylindrical symmetry. This platform's capabilities bridge observational gaps, enabling controlled initial conditions and direct measurements of plasma characteristics, crucial for refining astrophysical jet dynamics and improving the models accuracy.
First-principles design of heavy-atom-free singlet oxygen photosensitizers for photodynamic therapy
Authors: Pal Arun K. , Datta Ayan
Published: April 2024

In photodynamic therapy (PDT) treatment, heavy-atom-free photosensitizers (PSs) are a great source of singlet oxygen photosensitizer. Reactive oxygen species (ROS) are produced by an energy transfer from the lowest energy triplet excited state to the molecular oxygen of cancer cells. To clarify the photophysical characteristics in the excited states of a few experimentally identified thionated (>C=S) molecules and their oxygenated congeners (>C=O), a quantum chemical study is conducted. This study illustrates the properties of the excited states in oxygen congeners that render them unsuitable for PDT treatment. Concurrently, a hierarchy is presented based on the utility of the lowest-energy triplet excitons of thionated compounds. Their non-radiative decay rates are calculated for reverse-ISC and inter-system crossover (ISC) processes. In addition, the vibronic importance of C=O and C=S bonds is clarified by the computation of the Huang–Rhys factor, effective vibrational mode, and reorganization energy inside the Marcus–Levich–Jörtner system. ROS generation in thionated PSs exceeds their oxygen congeners as kf ≪ kISC, where radiative decay rate is designated as kf. As a result, the current work offers a calculated strategy for analyzing the effectiveness of thionated photosensitizers in PDT.
Perfect vortex beams with periodic coherence properties
Authors: Liu Xianlong , Wu Yilin , Zhu Kaiqi , Li Xiaofei , Cai Yangjian , Gao Yaru
Published: April 2024

Partially coherent perfect vortex beams with periodic coherence properties, namely, optical coherence perfect vortex lattices (OCPVLs), are proposed in this letter. Rhombus-, spiral-, and circle-shaped OCPVLs were investigated in detail both theoretically and experimentally through the manipulation of the coherent structures. Manipulating the coherence width yielded unique advantages, such as maintaining uniformity over a longer distance, more efficient optical trapping, and high-capacity free-space optical communications. OCPVLs with such advantages hold outstanding potential for applications in multi-particle trapping and manipulation.
Dependence of oxygen impurity concentration in AlN on the surface roughness during growth
Authors: Zhang Yuheng , Yang Jing , Liang Feng , Liu Zongshun , Hou Yufei , Liu Bing , Zheng Fu , Liu Xuefeng , Zhao Degang
Published: April 2024

In the cathode luminescence spectroscopic study of AlN thin films grown on c-plane sapphire, we found that the luminescence of 3–4 eV is correlated with O impurities, and it is first enhanced and then weakened with the increase in the temperature. The results of an SIMS test show that the concentration of O impurities in the samples is weakly correlated with the growth conditions but strongly correlated with the surface roughness of the samples at the time of growth. The rougher surface exposes more crystalline plane to the growth environment and different crystalline planes have different absorption capacities for O impurities, leading to an inhomogeneous distribution of O impurities in AlN. This inhomogeneous distribution results in a specific variation in the luminescence intensity of O impurities with temperature.
Study on spray characteristics of a compact pressure swirl nozzle integrating tangential inlet flow channel and swirl chamber
Authors: Yan Jin-Dong , Zheng Lei , Chen Hua , Cheng Wen-Long
Published: April 2024

Pressure swirl nozzles are widely applied in various heat and mass transfer applications due to advantages of reliable performance, simple structure, and easy processing. However, the complex design of the nozzle structure makes it difficult to miniaturize the pressure swirl nozzle, which restricts its use in limited spaces. In this study, a compact pressure swirl nozzle is proposed by merging a swirl chamber with the tangential inlet flow channel, addressing the issue of liquid atomization in limited spaces. The key geometric parameters are determined based on the internal flow properties by swirl chamber simulation. A spray test bench utilizing a phase Doppler particle analyzer and a high-speed camera was built to study the effect of pressure drop, geometric size, and nozzle inlet shape on spray characteristics. The simulation results show that the nozzle diameter and inlet shape are the main factors affecting flow in the swirl chamber. The experimental results further demonstrate that increasing nozzle diameter increases flow rate and spray cone angle, causing the droplets to move to the spray edge. The spray characteristics are affected by the inlet shape of the nozzle hole: radial velocity and particle size show a wider range of change with a funnel-shaped inlet. Axial velocity and pressure drop are obviously affected by a cylindrical-shaped inlet. This study provided a new design approach for pressure swirl nozzles and achieved flow rate of 5–35 l/h and Sauter mean diameter below 40 μm with an overall weight of 12 g. This compact nozzle construction is a reference for the design of atomizing nozzles in limited spaces.
Electrical control of the switching layer in perpendicular magnetic tunnel junctions with atomically thin Ir dusting
Authors: Lyu Deyuan , Khanal Pravin , Jia Qi , Guo Silu , Lv Yang , Zink Brandon R. , Zhang Yu , Yun Hwanhui , Zhou Bowei , Mkhoyan K. Andre , Wang Wei-Gang , Wang Jian-Ping
Published: April 2024

The use of magnetic tunnel junction (MTJ)-based devices constitutes an important basis of modern spintronics. However, the switching layer of an MTJ is widely believed to be an unmodifiable setup, instead of a user-defined option, posing a restriction to the function of spintronic devices. In this study, we realized a reliable electrical control of the switching layer in perpendicular MTJs with 0.1 nm Ir dusting. Specifically, a voltage pulse with a higher amplitude drives the magnetization switching of the MTJ's bottom electrode, while a lower voltage amplitude switches its top electrode. We discussed the origin of this controllability and excluded the possibility of back-hopping. Given the established studies on enhancing the voltage-controlled magnetic anisotropy effect by adopting Ir, we attribute this switching behavior to the significant diffusion of Ir atoms into the top electrode, which is supported by scanning transmission electron microscopy with atomic resolution.
Plasma–liquid interactions in the presence of organic matter—A perspective
Authors: Stapelmann Katharina , Gershman Sophia , Miller Vandana
Published: April 2024

As investigations in the biomedical applications of plasma advance, a demand for describing safe and efficacious delivery of plasma is emerging. It is quite clear that not all plasmas are “equal” for all applications. This Perspective discusses limitations of the existing parameters used to define plasma in context of the need for the “right plasma” at the “right dose” for each “disease system.” The validity of results extrapolated from in vitro studies to preclinical and clinical applications is discussed. We make a case for studying the whole system as a single unit, in situ. Furthermore, we argue that while plasma-generated chemical species are the proposed key effectors in biological systems, the contribution of physical effectors (electric fields, surface charging, dielectric properties of target, changes in gap electric fields, etc.) must not be ignored.
Low-temperature magnetoresistance hysteresis in vanadium-doped Bi2−xTe2.4Se0.6 bulk topological insulators
Authors: Düzel Birkan , Riha Christian , Graser Karl , Chiatti Olivio , Fischer Saskia F.
Published: April 2024

Bi2−xTe2.4Se0.6 single crystals show gapless topological surface states, and doping (x) with vanadium allows to shift the chemical potential in the bulk bandgap. Accordingly, the resistivity, carrier density, and mobility are constant below 10 K, and the magnetoresistance shows weak antilocalization as expected for low-temperature transport properties dominated by gapless surface states of so-called three-dimensional topological insulators. However, the magnetoresistance also shows a hysteresis depending on the sweep rate and the magnetic field direction. Here, we provide evidence that such magnetoresistance hysteresis is enhanced if both three-dimensional bulk states and quasi-two-dimensional topological states contribute to the transport (x = 0 and 0.03), and it is mostly suppressed if the topological states govern transport (x = 0.015). It is proposed that the hysteresis in the magnetoresistance results from different spin-dependent scattering rates of the topological surface and bulk states. Generally, this observation is of relevance to the studies of topologically insulating materials in which both topological surface and bulk states exist.
Numerical simulations of thermal capillary migration of a droplet on a temperature gradient wall with smoothed particle hydrodynamics method
Authors: Long Ting , Qin Yu , Wan Junjie
Published: April 2024

Thermal capillary migration is a phenomenon due to the Marangoni effect, which refers to the spontaneous motion of a liquid on a non-isothermal surface. Numerical simulation of thermal capillary migration of a droplet is extremely difficult due to the multi-physics field coupling and the violent motion of the droplet surface. In this paper, an improved smooth particle hydrodynamics (SPH) method is developed for simulating thermal capillary migration of a droplet driven by thermal gradient. In improved SPH model, an improved continuous surface force model is proposed to enhance the accuracy and stability of surface tension force calculation by introducing an improved surface tangential force. The contact angle model is utilized to model the surface wettability. The SPH method for simulating the thermal fluid flow is developed based on the continuum, momentum, and energy equations. In addition, kernel gradient correction and particle shifting technique are utilized to improve the accuracy and stability of the SPH method. The correctness and effectiveness of the improved SPH method are verified by numerical examples. Moreover, the motions of a droplet driven by thermal gradient under different conditions are investigated. Comparing with the results obtained by experiments and other resources, we can conclude that the improved SPH model is effective in modeling the thermal capillary migration of a droplet.
Radio frequency pulse marking of nuclear magnetization for magnetic flow metering: The impact of the flow profile
Authors: Schmieder Leonhard , Koss Peter A. , Kühnemann Frank , Bock Michael
Published: April 2024

This study explores how magnetization manipulation occurs in a flowing medium over a pipe geometry using nuclear magnetic resonance methods. In particular, the experimental conditions on radio frequency pulsing and the signal detection are studied in an ultra-low frequency regime of a few kilohertz. An analytical model of the magnetization preparation is presented, which calculates the magnetization distribution of an excited flowing segment. The effective flip angle distribution is mapped to simulate the temporal development of the magnetization in the segment. The simulation results are compared to the experimental data from a flow metering setup. As a result, the quantitative impact of the flow profile on the magnetic signal is shown.