bluuebunny/crossref_metadata_2025 huggingface dataset:
Palladium-Catalyzed Synthesis of Heterocyclic Ring Systems by Combination of Regioselective C–C with Twofold C–N Couplings
Authors: Langer Peter
Published: April 2022

The combination of regioselective palladium-catalyzed C–C with twofold C–N couplings allows for the synthesis of a variety of heterocyclic ring systems. Starting materials include thiophenes and benzothiophenes, pyrroles and indoles, furans and benzofurans, pyridines, quinolines and quinoxalines, complex heterocyclic systems and benzophenone derivatives. The products are in many cases complex polyheterocyclic systems, which are not readily available by other methods or, in a number of cases, were not described in the literature before. They are of pharmacological relevance or interesting in the field of material science. Products include thieno[3,2-b:4,5-b′]diindoles, thieno[3,2-b]indoles, thieno[3,4-b]indoles, 5,10-dihydroindolo[3,2-b]indoles, furo[3,2-b:4,5-b′]diindoles, benzo[4,5]furo[3,2-b]indoles, 5,7-dihydropyrido[3,2-b:5,6-b′]diindoles, 5,7-dihydropyrido[2,3-b:6,5-b´]diindoles, α-, β-, γ- and δ-carbolines, indolo[3,2-b]quinolines, indolo[2,3-b]quinolines, indolo[3,2-c]quinolines, indoloquinoxalines, pyrido[2′,1′:2,3]imidazo[4,5-b]indoles, thiadiazolo[2′,3′:2,3]imidazo[4,5-b]indoles, benzo[b]carbazolediones, acridones and thieno[3,2-b]quinolones.

Contents

1 Introduction

2 Thiophenes and Benzothiophenes

3 Pyrroles and Indoles

4 Furans and Benzofurans

5 Pyridines

6 Quinolines and Quinoxalines

7 Complex Heterocyclic Systems

8 2,3-Dibromonaphthoquinone

9 Benzophenone Derivatives

10 Conclusions
Diagnostic Efficacy of COVID-19 Rapid Antigen Detection Card in Diagnosis of SARS-CoV-2
Authors: Selvabai R Alice P. , Koshy Lino V. , Shanmugam Priyadarshini
Published: April 2022

Introduction The rapid surge of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) cases globally makes it essential for rapid diagnosis of coronavirus disease 2019 (COVID-19). Real-time reverse-transcription polymerase chain reaction (rtRT-PCR) remains as the gold standard to detect COVID-19 cases because of its greater sensitivity and specificity. However, because of its prolonged turnaround time and technical expertise, recommendations have been made to employ the use of rapid diagnostic test for rapid diagnosis and to curb the spread of the disease.

Methods This prospective study was performed in a tertiary COVID-19 care hospital located amidst the semi-urban settings. Both nasopharyngeal and throat swabs collected from the COVID 19 suspected study participants were subjected to both COVID 19 rtRT-PCR and rapid antigen testing.

Results Of the total 599 samples tested by rtRT-PCR, 310 (52%) were positive and 289 (48%) tested negative for SARS-CoV-2. Of the 599 samples tested by rapid antigen test (RAT), 230 (38%) were positive and 369 (62%) were negative. The overall sensitivity and specificity of our study kit was found to be 74.19 and 100%, respectively. The sensitivity of the RAT greatly overlaps with the viral load which is determined by the cycle threshold (CT) values of SARS-CoV-2, E gene, and RdRp gene.

Conclusion RAT yields rapid results within a short-turnaround time and found to be cost effective. Therefore, this test can be adopted in areas with rapid surge in SARS-CoV-2 cases which can help to rapidly identify the positive cases and to implement isolation and infection control measures.
Circadian pacemaker neurons display cophasic rhythms in basal calcium level and in fast calcium fluctuations
Authors: Liang Xitong , Holy Timothy E. , Taghert Paul H.
Published: April 2022

Significance

Daily rhythms in the molecular clock, in calcium, and in electrical activity all interact to support the functions of circadian pacemaker neurons. However, the regulatory mechanisms that unify these properties are not defined. Here, we utilize the cellular resolution of the
Drosophila
circadian neural circuit with technological improvements in light-sheet imaging. We report that individual
Drosophila
pacemakers display two cophasic rhythms of daily calcium fluctuations. We previously described the first: slow changes in intracellular calcium. The second involves high-frequency calcium fluctuations that depend on the function of the T-type calcium channel. We propose that the fast rhythms, emerging sequentially across the 24-h day, correspond to spontaneous electrical activity patterns displayed by different pacemaker groups.
Species divergence in gut-restricted bacteria of social bees
Authors: Li Yiyuan , Leonard Sean P. , Powell J. Elijah , Moran Nancy A.
Published: April 2022

Significance

The diversification of host-associated microbial communities depends on barriers to gene flow, imposed by confinement to different hosts or by niche partitioning within single hosts. However, most gut microbiomes are too complex to disentangle the diversification processes. Taking advantage of the simple gut microbiomes of social bees, we demonstrate that bee gut bacteria have diversified both between host species and within single host species through the acquisition of different ecological niches within the same gut. Our study further shows that gut microbiomes differ in spatial distributions within the same host, possibility due to adaptation to specified nutritional niches, such as urea utilization.
Lysosomes are required for early dorsal signaling in the
Xenopus
embryo
Authors: Tejeda-Muñoz Nydia , De Robertis Edward M.
Published: April 2022

Significance

The dorsal axis of the vertebrate
Xenopus
embryo is established by an early Wnt signal generated by a rotation of the cortex of the egg toward the opposite side of the sperm entry point. In this study, we report that lysosomal cathepsin D becomes activated on the dorsal marginal zone of the embryo already at the 64-cell stage, and that this asymmetry is enhanced by increasing Wnt signaling levels. We present experiments showing that lysosome acidification, macropinocytosis, and multivesicular body formation are required for the endogenous dorsal signal provided maternally in the egg. The results indicate that the cell biology of lysosomes plays an essential role in vertebrate development.
Two-dimensional transition metal-based electrocatalyst and their application in water splitting
Authors: Li Shubing , Fei Ben
Published: April 2022

The development and utilization of clean and renewable energy are significantly important to address the problem of environmental pollution and energy shortage. Hydrogen has been regarded as the most promising energy carrier due to its high energy density and environmental friendliness. Electrochemical water splitting provides an eco-friendly and sustainable way to produce hydrogen fuel. Therefore, highly efficient electrocatalysts are needed to be exploited for electrochemical water splitting to improve hydrogen production efficiency. Many transition metal-based electrocatalysts, abundant in nature and low cost, have gradually become the focus of research in recent years. Among them, two-dimensional (2D) transition metal-based electrocatalysts are of particular interest as they have the advantages of fast electron/proton transfer and abundant surface catalytic active sites. In this work, 2D transition metal-based electrocatalysts such as 2D transition metal oxide hydroxide, 2D transition metal phosphide, 2D transition metal carbides, etc., and their applications in water splitting are systematically reviewed.
Carbon dot-based molecular receptor for the colorimetric sensing of Cr(VI) from aqueous solutions
Authors: Daniel Sobhi
Published: April 2022

A novel molecular probe was fabricated by the integration of a smart carbon dot and a Schiff's base viz 4-amino -N-[(2-hydroxyphenyl)methylidene] benzoic acid. The synthesised carbon dot composite was well characterised, and a colorimetric molecular probe derived from ecologically sound carbon dot composite materials was explored for the colorimetric sensing of Cr (VI) in aqueous solutions. The results demonstrated that the developed colorimetric sensor can effectively sense Cr (VI) in aqueous solutions even below the picomolar concentration range. Also, the method's practical applicability was checked by the recovery of Cr(VI) from real tap water samples by the standard addition method and was found to be in the range of 99–109%.

Highlights

Chromium (VI) is considered as a severe environmental pollutant, due to its highly toxic and carcinogenic properties. Low cost, highly sensitive sensors for the determination of Cr(VI) are highly demanded. We have demonstrated a colorimetric molecular probe for detecting Cr(VI) based on the inner filter effect (IFE). This CD-based nano sensor provides obvious advantages of simplicity, convenience, rapid response, high selectivity, and sensitivity, which have potential application for the detection of Cr(VI) in the environmental industry. The developed colorimetric sensor can be effectively adopted for the sensing of Cr(VI) in aqueous solutions even below the picomolar concentration range. Based on the colorimetric observation we can qualitatively determine the presence of Cr(VI) without the aid of any sophisticated analytical instruments.

GRAPHICAL ABSTRACT
Factors affecting the shoulder functional profile in elite judo athletes
Authors: Delorme Julien , Blache Yoann , Degot Matthieu , Rogowski Isabelle
Published: April 2022

The aim was to investigate the effects of sex, age, preferred judo technique, dominance, and injury history on the shoulder functional status of elite judo athletes. Sixty‐one elite judo athletes (38 males, age: 18.1 ± 1.2 years, body mass: 69.3 ± 13.3 kg, body height: 172.2 ± 9.8 cm, brown belt to second‐degree black belt) completed three questionnaires: Western Ontario Shoulder Instability, Western Ontario Rotator Cuff, and Shoulder Instability‐Return to Sport after Injury. They performed four physical tests: the glenohumeral rotator isometric strength test, upper quarter Y‐balance test, unilateral seated shot put test, and modified Closed Kinetic Chain Upper Extremity Stability Test. The results showed that the female athletes had less shoulder functional abilities than the male athletes (p < 0.001 to p = 0.02). The younger athletes had poorer shoulder stability and upper extremity power than the older athletes (p < 0.001 to p = 0.02), but their glenohumeral muscles were stronger in both internal (p = 0.03) and external (p = 0.005) rotations. All the judo athletes had similar bilateral differences in shoulder functional status, except for judokas who preferred throwing techniques (p = 0.01). Injury history affected self‐perceived functional status (p < 0.001), as well as upper extremity muscle capacity and neuromuscular control (p = 0.01 to p = 0.05). This study provides new insight into the shoulder functional status of elite judo athletes, which may aid in the development of sports‐specific injury prevention and return‐to‐sport programmes to reduce the risk of shoulder injury occurrence and recurrence.

Highlights

Normalized levels of upper extremity abilities must be sex‐ and age‐specific in prevention programmes.

Prevention programmes may focus on muscle bilateral and anteroposterior symmetry.

Prevention programmes may include psychological training tailored to the sex of judo athletes.
QUBIC VII: The feedhorn-switch system of the technological demonstrator
Authors: Cavaliere F. , Mennella A. , Zannoni M. , Battaglia P. , Battistelli E.S. , de Bernardis P. , Burke D. , D'Alessandro G. , De Petris M. , Franceschet C. , Grandsire L. , Hamilton J.-Ch. , Maffei B. , Manzan E. , Marnieros S. , Masi S. , O'Sullivan C. , Passerini A. , Pezzotta F. , Piat M. , Tartari A. , Torchinsky S.A. , Viganò D. , Voisin F. , Ade P. , Alberro J.G. , Almela A. , Amico G. , Arnaldi L.H. , Auguste D. , Aumont J. , Azzoni S. , Banfi S. , Baù A. , Bélier B. , Bennett D. , Bergé L. , Bernard J.-Ph. , Bersanelli M. , Bigot-Sazy M.-A. , Bonaparte J. , Bonis J. , Bunn E. , Buzi D. , Chanial P. , Chapron C. , Charlassier R. , Cobos Cerutti A.C. , Columbro F. , Coppolecchia A. , De Gasperis G. , De Leo M. , Dheilly S. , Duca C. , Dumoulin L. , Etchegoyen A. , Fasciszewski A. , Ferreyro L.P. , Fracchia D. , Gamboa Lerena M.M. , Ganga K.M. , García B. , García Redondo M.E. , Gaspard M. , Gayer D. , Gervasi M. , Giard M. , Gilles V. , Giraud-Heraud Y. , Gómez Berisso M. , González M. , Gradziel M. , Hampel M.R. , Harari D. , Henrot-Versillé S. , Incardona F. , Jules E. , Kaplan J. , Kristukat C. , Lamagna L. , Loucatos S. , Louis T. , Marty W. , Mattei A. , May A. , McCulloch M. , Mele L. , Melo D. , Montier L. , Mousset L. , Mundo L.M. , Murphy J.A. , Murphy J.D. , Nati F. , Olivieri E. , Oriol C. , Paiella A. , Pajot F. , Pastoriza H. , Pelosi A. , Perbost C. , Perciballi M. , Piacentini F. , Piccirillo L. , Pisano G. , Platino M. , Polenta G. , Prêle D. , Puddu R. , Rambaud D. , Rasztocky E. , Ringegni P. , Romero G.E. , Salum J.M. , Schillaci A. , Scóccola C.G. , Scully S. , Spinelli S. , Stankowiak G. , Stolpovskiy M. , Supanitsky A.D. , Thermeau J.-P. , Timbie P. , Tomasi M. , Tucker C. , Tucker G. , Vittorio N. , Wicek F. , Wright M. , Zullo A.
Published: April 2022

We present the design, manufacturing and performance of the horn-switch system developed for the technological demonstrator of QUBIC (the Q&U Bolometric Interferometer for Cosmology). This system consists of 64 back-to-back dual-band (150 GHz and 220 GHz) corrugated feed-horns interposed with mechanical switches used to select desired baselines during the instrument self-calibration. We manufactured the horns in aluminum platelets milled by photo-chemical etching and mechanically tightened with screws. The switches are based on steel blades that open and close the waveguide between the back-to-back horns and are operated by miniaturized electromagnets. The measured electromagnetic performance of the feedhorns agrees with simulations. In particular we obtained a return loss around -20 dB up to 230 GHz and beam patterns in agreement with single-mode simulations down to -30 dB. The switches for this prototype were designed and built for the 150 GHz band. In this frequency range we find return and insertion losses consistent with expectations (<-25 dB and ∼-0.1 dB, respectively) and an isolation larger than 70 dB. In this paper we also show the current development status of the feedhorn-switch system for the QUBIC full instrument, based on an array of 400 horn-switch assemblies.
Analyzing the Hubble tension through hidden sector dynamics in the early universe
Authors: Aboubrahim Amin , Klasen Michael , Nath Pran
Published: April 2022

The recent analysis from the SH0ES collaboration has confirmed the existence of a Hubble
tension between measurements at high redshift (z > 1000) and at low redshift (z < 1)
at the 5σ level with the low redshift measurement giving a higher value.
In this work we propose a particle physics model that can help alleviate the Hubble tension
via an out-of-equilibrium hidden sector coupled to the visible sector.
The particles that populate the dark sector consist of a dark fermion, which acts as dark matter,
a dark photon, a massive scalar and a massless pseudo-scalar. Assuming no initial population of
particles in the dark sector, feeble couplings between the visible and the hidden sectors via
kinetic mixing populate
the dark sector even though the number densities of hidden sector particles
never reach their equilibrium distribution and the two sectors remain at different temperatures.
A cosmologically consistent analysis is presented where a correlated evolution of the visible and the hidden sectors with coupled Boltzmann equations involving two temperatures, one for the visible
sector and the other for the hidden sector, is carried out. The relic density of the dark matter constituted of dark fermions
is computed in this two-temperature formalism.
As a consequence, BBN predictions are upheld with a minimal contribution to ΔN
eff. However, the out-of-equilibrium decay of the massive scalar to the massless pseudo-scalar close to the recombination time causes an increase in ΔN
eff that can help weaken the
Hubble tension.
A prototype of quantum von Neumann architecture
Authors: Wang Dong-Sheng
Published: April 2022

A modern computer system, based on the von Neumann architecture, is a complicated system with several interactive modular parts. It requires a thorough understanding of the physics of information storage, processing, protection, readout, etc. Quantum computing, as the most generic usage of quantum information, follows a hybrid architecture so far, namely, quantum algorithms are stored and controlled classically, and mainly the executions of them are quantum, leading to the so-called quantum processing units. Such a quantum–classical hybrid is constrained by its classical ingredients, and cannot reveal the computational power of a fully quantum computer system as conceived from the beginning of the field. Recently, the nature of quantum information has been further recognized, such as the no-programming and no-control theorems, and the unifying understandings of quantum algorithms and computing models. As a result, in this work, we propose a model of a universal quantum computer system, the quantum version of the von Neumann architecture. It uses ebits (i.e. Bell states) as elements of the quantum memory unit, and qubits as elements of the quantum control unit and processing unit. As a digital quantum system, its global configurations can be viewed as tensor-network states. Its universality is proved by the capability to execute quantum algorithms based on a program composition scheme via a universal quantum gate teleportation. It is also protected by the uncertainty principle, the fundamental law of quantum information, making it quantum-secure and distinct from the classical case. In particular, we introduce a few variants of quantum circuits, including the tailed, nested, and topological ones, to characterize the roles of quantum memory and control, which could also be of independent interest in other contexts. In all, our primary study demonstrates the manifold power of quantum information and paves the way for the creation of quantum computer systems in the near future.
Exact and approximate solutions of the system of interrelated equations of the theory of creep and long-term strength
Authors: Arutyunyan A R , Saitova R R
Published: April 2022

The problem of creep and long-term strength of metallic materials and alloys is considered. Under the long action of high temperatures and relatively small stresses, many metallic alloys and pure metals loose plasticity and undergo brittle fracture. This problem in mechanics of materials is known as the phenomenon of thermal brittleness. To solve this problem Kachanov and Rabotnov introduced the concept of damage into the mechanics of materials. Also, they suggested a system of interrelated kinetic equations for creep deformation and damage parameter. In this work, a modified system of interrelated kinetic equations for creep deformation and damage parameter are formulated. In these equations, the mass conservation law is taking into account and the relative changes of material density are considered as a damage parameter. The results of numerous studies on the changes of porosity and density of various metals and alloys due to the formation and development of micropores and microcracks under conditions of high-temperature creep make it possible to consider density as an integral measure of the accumulation of structural microdefects. Different analytical and numerical solutions of the considered system of kinetic equations are obtained. It is shown, that the character of the curves according to different solutions is identical and agrees with the corresponding experimental results. It was shown, that the numerical solution completely coincides with the case of purely brittle fracture and small deformations. The long-term strength criterion is formulated. Comparison of theoretical creep and long-term strength curves with experimental results for 2.25Cr-1Mo steel is given. A good agreement between the corresponding theoretical and experimental results is observed.
Influence of metal texture and loading rate on heat release under quasi-static tension
Authors: Sudienkov Yu V , Smirnov I V , Zimin B A
Published: April 2022

This paper presents a study of the influence of the initial structure of metal materials obtained from plastic deformation methods on the processes of heat generation under quasi-static tension and low cyclic tests. Experimental data on the dependence of changes in the fraction of latent energy during deformation on the anisotropy of the initial structure of polycrystalline specimens of copper M1, duralumin D16, titanium VT6, as well as the grain size of copper M1 and magnesium alloy AZ31B are presented. It is shown that the thermodynamics of the plastic deformation process significantly depends on the anisotropy of the initial structure of the materials, brought about by the material processing used, as well as on the features of the lattice and the development of a meso-defect structure.
On the influence of an elastic film to the attenuation of wave motion between viscous and moving ideal fluid
Authors: Belonozhko D , Ochirov A
Published: April 2022

The regularities of wave motion along the interface of viscous and ideal liquids along which the surfactant is distributed are investigated in theory. The relationship between the decay decrements of capillary–gravitaty waves and the nature of maxima and minima surfactant concentration redistribution is established. The phenomenon has been analized in depend on the film elasticity in the presence of tangential velocity discontinuity at the boundary of the media. Influence of the tangential velocity gap on the relationship is established.
The dependence of the deformation behavior of fiberglass pipes on the initial disorientation of reinforcement subjected to repeated-static internal hydrostatic pressure and axial tension
Authors: Karapetyan K A , Sh Valesyan S , Muradyan N S
Published: April 2022

The problems of influence of the technological reinforcement disorientation on the deformation behavior of composite tubular elements subjected to repeated-static internal hydrostatic pressure and axial tension, as well as the resistance to fracture of these elements subjected to the above-mentioned loading are discussed.

The experimental part of research is carried out applying thin-walled tubular elements manufactured from the fiberglass fabric prepreg based on the modified epoxy resin.

It is established that a possible deviation of the reinforcement angle from 60 to 80 taking place during the processing of material into goods has little effect on the fracture resistance both subjected to the internal hydrostatic pressure and axial tension of fiberglass pipes manufactured so that the directions of reinforcing fiberglass fabric warp and ones axis are coincided.

Meanwhile, the following was stated that the accompanied shearing deformations are arising besides the basic cyclic deformations (noted in the direction of force application) for initially disorientation fiberglass pipes in difference from non-disoriented ones at the condition of pulsating (irregular) loading by the above-mentioned load-bearing factors.

Calculations are proved that the reinforcement disorientation direction in the above-underlined limits is brought to the significant decrease of the energy dissipation coefficient of fiberglass pipes.

The statement aiming the constructional solution of the problem is formulated in a sense of negative influence of the technological reinforcement disorientation on the composite tubular elements functioning at the conditions of cyclic axial tension and internal hydrostatic pressure.
Inhomogeneous transversely isotropic space under influence of concentrated power and temperature sources
Authors: Kryvyi O F , Morozov Yu O
Published: April 2022

The problem of constructing fundamental solutions to the thermoelasticity problem for a piecewise-homogeneous transversely isotropic space is reduced to the matrix Riemann problem in the space of generalized slow growth functions. As a result of the solution of which, were obtained expressions in explicit form for the components of the stress tensor and the displacement vector in plane of connection of transversely isotropic elastic half-spaces containing concentrated stationary heat sources. The temperature distribution is investigated depending on the thermophysical characteristics of the half-space materials.
Finding coefficients in the problem of a cylindrical shell with a circular cutout
Authors: Kashtanova S V , Rzhonsnitskiy A V
Published: April 2022

In the present paper a cylindrical shell with a circular cutout is considered. There have not yet been explicit formulas for the field of stresses and after reviewing some ideas of the derivation of the solution of this problem, the authors can present how this can be done. A new approach is based on the separation of variables in the basis function by Fourier decomposition and on the proof of reducibility of the system. This way has a strict mathematical foundation, and for the boundary condition in the form of axial tension the limit transition leads for the Kirsch problem, as expected. In this work a finding of coefficients for small parameter is illustrated and the limit transition is shown.
On melting temperature of carbon produced in detonation combustion of acetylene
Authors: Prokhorov E S
Published: April 2022

A mathematical model of gas detonation of over-riched hydrocarbon-oxygen mixtures has been formulated. The model implies numerical studying the equilibrium flows of detonation products provided that there is condensation of free carbon. To describe thermodynamic properties of carbon condensate, reference data for graphite have been used. The calculations have been compared with the known results of experimental research, in which the detonation of acetylene-oxygen mixture in a tube with one closed end results in nanoscale particles of carbon material with special properties. We assumed that melting temperature of such a material, which is about 3100 K, is lower than that of graphite. Only such a way of correcting melting temperature yields the best agreement (with accuracy of about 3%) between calculation and experimental dependence of detonation front velocity on molar fraction of acetylene in the mixture.
Investigation of phase and temperature perturbations induced by a candle using Hilbert optics methods
Authors: Arbuzov V A , Arbuzov E V , Dubnishchev Yu N , Zolotukhina O S , Lukashov V V
Published: April 2022

The method of multiwave RGB-optical Hilbert diagnostics of the phase and temperature spatial structure of the flame (in an air flow heated by a candle flame) at a fixed moment of time is discussed. The object of study satisfies the model of axial symmetry of the torch associated with the vertical orientation of the candle. The reliability of the received results is confirmed by comparing the reconstructed radial temperature by experimental hilbertogram with data measured by a thermocouple. The flickering effect of the flame was not taken into account in the work, this is the subject of further research.
Determination of the fire hazard of forest plantations depending on surface fuels under laboratory combustion conditions using thermophysical parameters
Authors: Malenko A A , Chichkarev A S , Kasymov D P , Agafontsev M V , Savin M A
Published: April 2022

The work aims to investigate experimentally the assessment of the combustion parameters of forest vegetation based on received ignition and combustion characteristics according to the presence of surface forest fuels (FF). The research was carried out using the laboratory test facility, which allowed simulating various types of combustion. Using the thermocouple method, as well as the heat flow sensor, made it possible to control the thermal characteristics. The maximum heat fluxes that are characteristic of FF fractions, such as oak bark, Salix acutifolia branches, and oak wood reached 49±3.5 kW/m2. Among grass species, the highest heat fluxes were recorded during the combustion of narrow-leaved bluegrass (47.4±3.21 kW/m2). The amount of stored energy directly depends on the material structure, density, and initial moisture content. It should be taken into account that the fire hazard of a forest area depends on pyrological properties, and especially on the moisture content of the dominant type of fuel bed.
Experimental studies of the combustion of pulverized coal to form the basis for training a neural network
Authors: Butakov E B , Pochtar A S , Vinogradov S V , Burdukov A P
Published: April 2022

In this paper, we considered the solution to the problem of efficient and environmentally friendly combustion of hydrocarbon-containing fuels and the prevention of emergencies in combustion chambers and boiler plants. On the basis of the existing scientific background and the existing instrumental and experimental base, modern technologies for automating the combustion process using machine learning methods have been developed. Automation will reduce energy costs and prevent possible emergencies at thermal power plants and combustion chambers. The approbation of the technology and the formation of a data corpus for training the network was carried out using semi-industrial fire installations with a thermal power of about 5 MW, which make it possible to vary the parameters of fuel combustion in a wide range and, accordingly, to implement various combustion modes.
Study of the processes of joint grinding and ignition of coal with wood raw materials
Authors: Kuznetsov A V
Published: April 2022

The conditions for obtaining composite fuel “coal-pine sawdust” on a semi-industrial roller mill RM-20 were selected: the rotor speed was varied from 10 (300 rpm) to 40 Hz (1200 rpm). The ignition of the obtained samples was studied, and the optimal composition of the composite was determined.
Effect of repetitive irradiation on ion saturation current of laser ablation plasma using 1 kHz repetitive laser
Authors: Igarashi K , Iwasa M , Takahashi K , Sasaki T , Kikuchi T
Published: April 2022

We demonstrated 100 shots of burst laser irradiation with an Al target using a 1 kHz repetitive pulse laser. By using the laser, we generated ablation plasmas with a repetition rate of 1 kHz. The time-evolution of ion saturation current density in the generated ablation plasma was measured using the orifice probe. The result shows that the waveforms on 100 spikes were observed. The ion saturation current density decreased rapidly from the first to the third shot and reached a minimum value at the fourth shot. After the fourth shot, it reached 1 μA/mm2 at the 53rd shot and settled at 0.5 μA/mm2. We extracted the time-evolution of ion saturation current densities of the first, 10th, 50th and 100th shots. The drift velocities were estimated by Time of Flight from the time-evolution of current. The result shows that the drift velocity of the ablation plasma increases with the increase in the number of shots.
Progress of the High-Current EBIS Charge Breeder for the FRIB
Authors: Son Hyock-Jun , Lapierre Alain , Villari Antonio C.C. , Henriques Ana , Supangco Charisse , Knowles Cody , Crisp Daniel , Nash Samuel , Beebe Edward N
Published: April 2022

The ReA post-accelerator of the National Superconducting Cyclotron Laboratory employs an Electron-Beam Ion Trap (EBIT) as a charge breeder to reaccelerate rare-isotope beams to several MeV/u. The Facility for Rare-Isotope Beams (FRIB) is near completion and will provide RIB rates expected to exceed in some cases 1010 particles/s. The ReA EBIT operates with an electron current of 300 – 600 mA, corresponding to an electron current density of 170 – 340 A/cm2 and a maximum trap capacity of 1010 elementary charges, which can be insufficient to handle high FRIB rates. A High-Current Electron-Beam Ion Source (HCEBIS) has been constructed based on the backbones of the TEST EBIS from the Brookhaven National Laboratory. By using a 4-A electron beam, a current density of 298 A/cm2 and a maximum trap capacity of 2.4×10n elementary charges can be achieved. This paper presents the status of the HCEBIS. It also includes results of electron- and ion-beam simulations and discusses electron-beam commissioning plans.
A picosecond laser-based ion source for injection into a high capacity EBIS in both accumulation and single pulsed modes
Authors: Kondrashev S. , Beebe E , Kanesue T. , Okamura M. , Scott R.
Published: April 2022

Ps-lasers have advantages for generation of low charge state ions compared to ns-lasers because the influence of heat conductivity on a solid target is negligible in the case of ps-laser ablation for laser pulse durations shorter than 10 ps. By using a laser with high rep-rate, it is possible to produce quasi continuous 1+ ion beams for periods up to tens of milliseconds, making it possible to take advantage of the ability of the EBIS to trap 1+ ions in accumulation injection mode. We studied the properties of Al, Ti, Cu, Nb, and Ta plasmas generated by a ps-laser with 1.27 mJ energy within an 8 ps pulse to investigate feasibility and specify parameters of a laser ion source for RHIC EBIS using accumulation injection mode. It is shown that a both accumulation and single pulsed injection modes are accessible with a single ion source geometry and single injection line, providing the most attractive option for an ion source for external injection into RHIC EBIS trap based on a ps-laser.
CANREB EBIS commissioning at TRIUMF
Authors: Schultz B.E. , Charles C.R.J. , Cavenaile M. , Kanungo R. , Ames F. , Kester O.
Published: April 2022

The Canadian Rare Isotope facility with Electron Beam ion source (CANREB) is an essential part of the Advanced Rare IsotopE Laboratory (ARIEL) presently under construction at TRIUMF. CANREB was recently commissioned and can accept stable or rare isotope beams from a variety of ion sources, delivering high purity beams of highly charged ions (HCI) to experiments. The injected beams are bunched using a radiofrequency quadrupole cooler-buncher and energy adjusted using a pulsed drift tube for injection into the electron beam ion source (EBIS) charge state breeder. The EBIS is designed for a maximum electron beam current of 500 mA and a maximum magnetic field of 6 T. Ions with energies up to 14 keV can be injected and HCI with mass-to-charge (A/q) ratios 3 ⩽ A/q ⩽ 7 can be charge bred and extracted. The HCI are A/q-selected using a Nier-type spectrometer before being transported to the ISAC linac for post-acceleration. Results from CANREB beam commissioning with focus on the EBIS will be presented.
Beam Formation Studies on the CERN IS03b H Source
Authors: Lettry J , Vnuchenko A , Bertolo S , Mastrostefano C , O’Neil M , di Lorenzo F , Coutron Y , Steyeart D , Riffaud B , Thiboud J , Guida R , Kapusniak K , Charvet C , Teissandier B , Moyret P , Roncarolo F , Bart Pedersen S , Duraffourg M , Vuitton C , Fantz U , Mochalskyy S , Wunderlich D , Lindqvist M , den Harder N , Mimo A , Briefi S , Hurlbatt A , Kalvas T , Minea T , Revel A
Published: April 2022

An H- ion source is being operated at the new 160 MeV linear injector (Linac4) of the CERN accelerator complex. The source’s plasma is of the Radio Frequency Inductively Coupled Plasma type (RF-ICP), without magnetic cusp and runs with Cs-loss compensation [1]. Vertical downward oriented filter- and electron dump-dipolar magnetic fields expand over the plasma chamber, beam-formation, beam-extraction and electron dump regions and generate horizontal asymmetry and beam angular deflection partially compensated by mechanical alignment of the front-end. The H- beam is generated via volume and caesiated plasma surface modes, the latter inducing a radial asymmetry characterized by an increased current density close to the plasma electrode surface [2]. Asymmetries affecting the meniscus shape, or its current density have to be simulated via 3D Particle In Cell Monte Carlo (PIC-MC) solvers, such as the Orsay Negative Ion eXtraction code (ONIX) [3]. Validation of these simulations require dedicated measurements. This contribution describes experimental methods newly implemented at CERN’s ion source test stand and initial results for Optical and Beam Emission Spectroscopy (OES, BES), emittance and beam profile measurements. In a later stage, the gathered data sets can be compared to source plasma parameters and extracted beam parameters from PIC-MC simulations, once coupled to the Ion Beam Simulation (IBSimu) [4] beam transport code. The experimental parameter space includes RF-power, density of neutrals, position of the RF coil and extraction field. Beams of H-, D- and protons were produced; examples of measured data are presented in this contribution.
Application of Thomson scattering system toward direct measurement of extraction surface of the negative ion beam
Authors: Hiratsuka J , Tomita K , Kashiwagi M , Kojima A , Saquilayan G Q , Kaihori T , Ichikawa M , Kisaki M , Tobari H , Watanabe K
Published: April 2022

As a challenge to measure the extraction surface of the negative ion beam, a laser Thomson scattering system with high spatial resolution was applied to a weakly ionized plasma in a negative ion source for the first time. The first target was to measure electron density around extraction region because shape of the extraction surface can be estimated by electron spatial profile. However, stray light by injected laser, filament and plasma was too intense compared to signal from the low density region. To solve this, a triple grating spectroscopy and a multilayer black screen were introduced, and the laser spot size was minimized to reduce slit sizes of the spectroscopy. As a result, electron density was successfully measured accurately in low density region. From an error estimation, measurement of electron density 3 × 1016 m-3 with spatial resolution of 0.5 mm at extraction region can be realized with accumulation of signals from multiple laser shots. This system can contribute to the understanding of the mechanism of formation of the extraction surface, which is a long-term issue in the negative ion source.
ITER-HNB plasma and extraction grids in BUG: Characterization of magnetic deflection correction
Authors: Harder Niek den , Hurlbatt Andrew , Wimmer Christian , Orozco Guillermo , Nocentini Riccardo , Fröschle Markus , Heinemann Bernd , Fantz Ursel
Published: April 2022

The BATMAN Upgrade test facility aims to extract H-/D- at high current densities. The inevitably co-extracted electrons are deflected out of the beamlet by permanent magnets before acceleration. These magnets induce a row-wise zig-zag deflection of the beamlets. In the new MITICA-like extraction system, this deflection is compensated by additional deflection correction magnets. IBSimu modeling studies indicate that the deflection correction system not only acts on the horizontal beamlet deflection, but also causes aberrations to the vertical angular distribution. Dependencies of the beamlet position and size are studied in several parameter scans with the available diagnostic tools (CFC tile calorimetry, Beam Emission Spectroscopy). The horizontal beamlet deflection is robustly compensated within the systematic uncertainty of the experiment. The triangular beamlet shape predicted on basis of the magnetic field structure is visible in the CFC calorimetry.
nuCARIBU : An upgrade for the CARIBU facility at the Argonne Tandem Linac Accelerator System
Authors: McLain J. , Dickerson C. A. , Gott M. , Greene J. , Nolen J. , Savard G. , Song J. , Vondrasek R. C.
Published: April 2022

The Californium Rare Isotope Breeder Upgrade (CARIBU) facility is changing the mechanism for creating neutron-rich fission products. Spontaneous fission from a 252Cf source has provided beams to support the low energy and accelerated-beams ATLAS programs. 252Cf has a 2.65-year half-life, requiring the source to be replaced every three years to maintain high beam intensities. Fabricating an appropriately thin 252Cf source to efficiently release the fission products has been challenging. The solution to these problems is nuCARIBU, a new system that provides neutron-induced fission on actinide foils. The Best Cyclotron B6P System (6-MeV proton beam at 0.5mA) is chosen, utilizing a multi-cusp negative ion source extracting into a cyclotron, which uses carbon foils to strip the H- ions to protons. These protons are delivered to a 7Li target to produce neutrons. The fast neutrons are moderated to thermal energies to induce fission in an actinide foil, providing neutron-rich fission products. These subsystems are described in detail along with comparisons between the current CARIBU facility and the presented nuCARIBU facility.

This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357
Design and thermal simulations towards a high intensity radioactive ion source for ISOL@MYRRHA
Authors: Hurier Sophie , Rijpstra Kim , Creemers Philip , Ramos João Pedro , Popescu Lucia , Cocolios Thomas Elias
Published: April 2022

MYRRHA will be the world’s first large-scale Accelerator Driven System project at power levels scalable to industrial systems. ISOL@MYRRHA will produce Radioactive Ion Beams (RIBs) using the Isotope Separation On-Line (ISOL) technique, with increased isotope production by high intensity primary beams over a long period while maintaining a high-quality RIB. Higher atom flux produced prevalently affects the ISOL ion source. A surface ion source is chosen as a first source because of its reliability and simple design. To understand the hot cavity’s behaviour, finite element thermal-electric simulations were performed. To start, a heating system study with experimental results from the SPES project was reproduced. This concept was then modified by: electrically insulating the source from its support, adding a feedthrough, transforming a passive thermal screen into an active part. With this heating system upgrade, the ion source temperature profile can be adjusted, especially at its exit part where high temperature is expected to play a crucial role in ion production and extraction.
Improvement of the FEBIAD ion source at SPIRAL1
Authors: Bosquet V. , Jardin P. , Chauveau P. , Damoy S. , Delahaye P. , Dubois M. , Hormigos S. , Maunoury L. , Michel C. , Thomas J.C.
Published: April 2022

The behaviour of the Forced Electron Beam Induced Arc Discharge (FEBIAD) ion source used at GANIL within the Target Ion Source System (TISS) of the “Système de Production d’Ions Radioactifs Accélérés en Ligne” (SPIRAL1) has been recently investigated to improve its performances and render them reproducible. Off line systematic studies of the evolution of working parameters (cathode shape, cathode heating, anode current) with time and temperature configuration have clearly shown the origin of issues was mainly related to an excessive temperature of the anode insulators. Modifications of the TISS have allowed the reduction of the anode current drift and an ionisation efficiency of 40Ar of 15%, stable over more than eight days. The system is still under improvement to stabilize its Ar ionization efficiency to 25%, which is the maximum observed during testing.
A Low Energy H- Beamline for the ALPHA Antihydrogen Experiment
Authors: Bertsche W. A. , Faircloth D. , Johnson M. A. , Kalvas T. , Lawrie S. , Tarvainen O.
Published: April 2022

The CERN ALPHA experiment makes precision measurements of antihydrogen atoms, confined in a superconducting magnetic minimum trap. Recent measurements of the antihydrogen spectrum have already provided high-resolution tests of fundamental symmetries, and ALPHA has now embarked on an ambitious upgrade programme aimed at directly comparing hydrogen and antihydrogen within their existing atom trap. One aspect of this upgrade will be the development of a low-energy (50 eV) hydrogen ion source that is compatible with ALPHA’s existing magnetic charged particle beamlines. PELLIS, previously developed at JYFL, is a 5 keV filament-driven source that generates H- beams with low emittances and currents of up to 50 μA. Here, we explore the feasibility of a proposed electrostatic beamline design to transport H- ions from a PELLIS-type ion source into ALPHA’s various particle traps. We present SIMION simulations that were used to develop the beamline, focusing on components such as a quadrupole switchyard and drift tube deceleration stage.
Comparative study on biomass treatment equipment based on dry anaerobic fermentation and direct combustion treatment
Authors: Huang Yixin , Zhang Yan
Published: April 2022

Biomass energy has great application potential, but direct combustion of biomass not only has low utilization rate, but also is easy to produce secondary pollution. In order to make better use of biomass, through the application of biomass fermentation equipment of dry anaerobic fermentation technology, this paper carries out simulated fermentation experiments, compares the results of direct combustion treatment, draws the conclusion that the technical and economic effect of fermentation treatment is more advantageous, and points out that the treatment mode of biomass treatment should be reasonably selected for efficient and convenient treatment in the future
Wind Power System for Grid-connection Based on PMSG and PI Controlling under Variable Wind Speed
Authors: Liu Hengchao
Published: April 2022

Wind power is an important part of sustainable energy development and plays a pivotal role in the background of the ‘Dual Carbon’ goal. In this paper, a wind power grid-connected model based on Permanent Magnetic Synchronous Generator(PMSG) is proposed. The pitch angle of the wind turbine and the waveform of the grid-side currents are controlled by the PI controller in order to realize the tracking of the power frequency and phase of the grid voltages, and eventually achieve the purpose of grid-connection. By utilizing MATLAB/Simulink, the simulation results reveal that the final output currents’ frequency and phase meet the requirements of grid-connection, and the Total Harmonic Distortion(THD) of the current waveform is less than 2%, which represents a high power quality. It can provide reference for efficient and convenient grid-connection of wind power generation.
Application of flow battery energy storage system at the end of rural power grid
Authors: Yang Yang , Zhang Xin , Mei Kuang , Zhang Kejie , Yao Jun , Zhang Aifang , Cai Wei , Du Tao
Published: April 2022

The mobile energy storage power station based on the all vanadium flow battery has many advantages such as flexible layout, adjustable power capacity and high application efficiency. It can achieve effective support for active and reactive power at the end of the rural power grid and voltage and frequency regulation, and comprehensively improve the power supply capacity and quality of the end of the rural power grid. In order to select suitable application demonstration points to verify the above functions, a survey was conducted on the low voltage at the end of the rural power grid. Based on the experience of local staff and the comprehensive geographic factors of local monitoring system data, the end of a certain rural power grid was selected as the pilot area. The capacity of the transformer in the distribution station area was 50kW to supply power to approximately 50 households. The 50kW/100kWh all vanadium redox flow battery was selected as the energy storage system.