bluuebunny/crossref_metadata_2025 huggingface dataset:
On a system of independent arguments for constitutive tensor functions on the growing surface in micropolar continuum
Authors: Murashkin E V
Published: April 2022

The present study is devoted to the boundary value problems statements for the growing materials with microstructural features. The general form of tensor relations on the propagating growing surface is derived as a consequence of the conservation laws of momentum and angular momentum. The necessary system of independent arguments of constitutive differential constraints on the growing surface in micropolar continuum is determined. A complete set of joint rational invariants of the system of tensors and vectors that determine the thermodynamics of the production process of a woven 3D material is given and discussed. An invariant-complete formulation of the constitutive relations on the growing surface is obtained.
Residual stresses calculation in a thermoelastoplastic torus after cooling
Authors: Dats E P , Kovalev V A , Murashkin E V
Published: April 2022

The present study deals with the boundary value problems under toroidal symmetry conditions. The residual stresses after cooling (unloading) in an elasto-plastic material are calculated. Throughout the paper the conventional Prandtl-Reuss model is generalised and used. The solution to the problem of hollow torus cooling under a temperature gradient is obtained and discussed. Analytical solutions, as an approximation of complete boundary value problem, describing residual deformations and stresses under conditions of toroidal symmetry are constructed and discussed.
Exact and beam solutions for a narrow clamped rectangle
Authors: Kovalenko M D , Menshova I V , Kerzhaev A P , Shulyakovskaya T D
Published: April 2022

The paper presents formulas describing an exact solution to the boundary value problem of the theory of elasticity in a rectangle in which the horizontal sides are rigidly clamped, and normal and tangential stresses are given on the vertical ones. Only an odd-symmetric deformation of the rectangle with respect to the horizontal axis of symmetry and an even-symmetric deformation of the rectangle with respect to the vertical axis of symmetry are considered. The paper is based on the previously obtained solutions for a free half-strip and a free rectangle.
Development of a mathematical model of a force actuator for the opening of a space structure with transformable configuration
Authors: Zimin V N , Krylov A V , Kuvyrkin G N , Shakhverdov A O
Published: April 2022

The prospects for the development of radio astronomy, solar energy, space communications, exploration of the Earth’s surface and other planets from space are currently associated with the creation of fundamentally new large-sized space structures. The inevitable complication of the design schemes of promising large-sized systems due to the increase in their operational functionality requires the development of mathematical models that adequately describe the mechanical properties of structures. When designing large-sized systems, the scheme of which allows for automatic configuration change of the structure, it is necessary to take into account shock loads. They inevitably arise when the working state of the structure fixes in orbit upon completion of the process of its opening. To ensure smooth, reliable and shock-free opening of large-sized space structures, it is proposed to use force actuators with active elements made of titanium nickelide material with a shape memory effect. During the tests of the active elements, the main parameters of the force actuator were determined: the generated force, the actuation time and the length of the working stroke. The length of the working stroke was determined by the change in the relative elongation of the active element of the force actuator during its heating. The conducted experimental and theoretical studies are aimed at developing a mathematical model of the functioning of an active element made of titanium nickelide with a shape memory effect for the opening of a space structure with transformable configuration.
Thermodynamic simulation of radioactive graphite combustion in water vapor
Authors: Barbin N M , Kobelev A M , Terent’ev D I , Alexeev S G , Titov S A
Published: April 2022

The paper analyzes the gas phase, the behavior uranium, the calculation of thermophysical properties during heating of nuclear reactor graphite containing various actinides. The study was carried out by thermodynamic modeling using the TERRA software package in the range from 423 to 2123 K at a constant pressure of 0.1 MPa. Up to a temperature of 623 K, the main components of the gas phase are water vapor, carbon dioxide, methane and hydrogen. Above 1023 K, the gas phase contains predominantly carbon dioxide and monoxide. It was revealed that in the range of 423-923 K uranium is present in the form of condensed compounds - uranium dioxide and uranyl chloride. Up to a temperature of 1623 K, uranium is present in the form of condensed uranium dioxide and calcium uranate. At temperatures above 2023 K, condensed uranium compounds are converted into gaseous and ionized compounds of uranium trioxide and dioxide. The thermophysical characteristics change unevenly up to a temperature of 923 K.
Numerical study of the effect of superheated steam supply during the combustion of liquid fuel in a burner on the reduction of harmful emissions
Authors: Kuznetsov V A , Dekterev Ar A , Anufriev I S , Minakov A V
Published: April 2022

In this work, the process of combustion of hydrocarbon fuel in the original burner of the evaporative type with the supply of superheated water vapor to the reaction zone is investigated using numerical modeling. N-heptane was used as a model fuel. The turbulent flow of gases was modeled on the basis of the RANS (Reynolds-averaged Navier–Stokes) approach. The combustion was simulated with the EDC (Eddy Dissipation Concept) model using a reduced chemical reaction mechanism. Calculation studies of the effect of steam on the processes occurring in the combustion chamber were carried out. Comparative analysis of the calculation results with experimental data showed good agreement in terms of the main integral parameters. The positive effect of the influence of steam injection into the active combustion zone of hydrocarbon fuel on the reduction of harmful emissions is shown.
Energy distribution and bremsstrahlung spectra of energetic electrons escaping from the ECR plasma with high energy input
Authors: Kiseleva E.M. , Izotov I. V. , Skalyga V.A. , Vybin S.S , Lapin R.L.
Published: April 2022

Electron energy distribution function (EEDF) is an important characteristic that defines the processes of plasma confinement and ionization. Understanding such processes is crucial for the proper tuning of ion sources. In the ECR plasma, the EEDF is significantly non-Maxwellian, and the exact shape remains still unknown. As the initial step towards the EEDF resolving, the energy distribution of the electrons lost from the magnetic mirror trap was directly measured in a wide range of neutral gas pressures and gyrotron powers along with bremsstrahlung spectra. A series of experiments were performed on the newly constructed Gasdynamic Ion Source for Multipurpose Operation (GISMO) facility allowing record-breaking specific energy input into the plasma. Obtained distributions showed unconventional behavior as the function of source parameters. The EEDF shape and the bremsstrahlung spectra showed a threshold qualitative change with the gyrotron power presumably as a result of the development of kinetic instabilities.
Experimental study on dynamic effects of H- and D- negative ions in an ECR-plasma source
Authors: Mitrou M , Svarnas P , Béchu S
Published: April 2022

The electrostatic probe-based photo-detachment technique with one or two laser beams can provide insight on the negative ion absolute densities and dynamics, respectively, in electronegative plasmas. In this work, this diagnostic is installed in the ECR-driven (2.45 GHz) negative ion source “Prometheus I” and details of the setup design along with main underlying physics are discussed. Potential origins of signal distortions and thus erroneous employment of this technique are demonstrated. Based on these observations, H- and D- negative ion densities and temperatures are measured in a reliable manner. The experiments are carried out for variable microwave power (2.45 GHz), at 1.33 Pa, unveiling two distinct kinetic equilibriums of the negative ions, in both gases, and an isotope effect.
H- and D- production efficiency in a multi-dipole ECR-plasma source as a function of gas pressure
Authors: Mitrou M , Svarnas P , Béchu S
Published: April 2022

The electron cyclotron resonance (ECR) negative ion source “Prometheus I” is operated either with high purity H2 (> 99.999%) or D2 (> 99.8%) to probe H- and D- ions, respectively, and examine the isotope effect within a wide range of gas pressure. These ions are predominantly formed in the bulk plasma by dissociative attachment (DA) of low-energy (cold) electrons to highly ro-vibrationally excited molecules. The latter result mainly from the radiative decay and excitation (EV) process sustained by high-energy (hot) electrons heated in the ECR zones. Langmuir probe and laser photo-detachment measurements are realized within the pressure range 0.27 to 2.67 Pa under constant microwave power (0.9 kW). It is revealed that: (i) the plasma potential, cold electron temperature, and cold electron density tend to be higher in deuterium; (ii) no pronounced difference in the hot electron density and temperature is found between the two plasmas; and (iii) overall a similar H- and D- negative ion yield (up to 6×109 cm-3; under the present conditions) is achieved. However, for equal plasma densities an isotope effect is exhibited showing higher H- density over the entire pressure range. Finally, the nH- / n ratio is constantly higher than the nD- / ne one and they both peak around 1.33 Pa.
Development and status of the FRIB 28 GHz SC ECRIS
Authors: Ren Haitao , Machicoane Guillaume , Bultman Nathan , Rao Xing , Morrison Phil , Omelayenko Mykola , Tobos Larry , Fogleman Jesse , Felice Helene , Hafalia Ray , Pan Heng , Prestemon Soren
Published: April 2022

T o meet a beam power requirement of 400 kW for heavy ions, a high intensity 28 GHz superconducting Electron Cyclotron Resonance (ECR) ion source is under development at the Facility for Rare Isotope Beams (FRIB) in collaboration with Lawrence Berkeley National Laboratory (LBNL). The magnet was built and tested at LBNL and integrated into the ion source cryostat on the FRIB high voltage platform. Magnet cooldown to 4.2K was completed successfully in December of 2020. The static heat load at 4.2K has been measured to be around 1.2 W, in good agreement with the design value. The heat load is managed through 2 Gifford-McMahon/Joule-Thomson (GM-JT) cryocoolers that have been in operation for several months. Magnet energization is scheduled in November of 2021. Warm components preparation and assembly test are ongoing in parallel. The ion source commissioning with 18 GHz Klystron shall start in December of 2021. Details of the ion source development, status, and commissioning plan will be presented in the paper.
A few ECRIS developments at LBNL
Authors: Xie D , Benitez J , Todd D
Published: April 2022

In addition to the ongoing investigation of bremsstrahlung radiation produced by energetic electrons in the superconducting Electron Cyclotron Resonance (ECR) ion source VENUS, the LBNL ion source group has pursued several other research topics since 2015 to explore potential advancements of ECR ion sources. Three of these activities are investigations into the benefits of non-cylindrical plasma chambers, the development of new high-temperature ovens that will efficiently produce the intense, metallic ion beams necessary for super heavy element production at the 88-Inch Cyclotron facility, and the finalization of the conceptual and engineering design of the superconducting NbTi magnet structure for the 4th generation, 45 GHz ECR ion source MARS-D. This article summarizes and briefly discusses the highlights of these ECRIS developments.
Low Z gas mixing effects of Ar and Xe multicharged ions in electron cyclotron resonance ion source
Authors: Tsuda K , Kubo W , Harisaki S , Anan M , Sato K , Owada I , Maenaka T , Kato Y
Published: April 2022

An electron cyclotron resonance (ECR) ion source (ECRIS) has wide applications such as cancer therapy and material synthesis. We have constructed a single ECRIS capable of producing various ions with low to high mass/charge ratio, and have been conducting various experiments. We focus on the efficient production of multicharged ions and aim to increase the yield of multicharged ions by new effects of electromagnetic waves in ECRIS. We investigated the possibility of selective heating to low Z ions under low Z gas mixing. Therefore, as a preliminary step of these experiments, the low Z gas mixing effect with rare gases are investigated. The optimum mixing ratio of the main gas Ar and the low Z gas He was investigated by varying the mixing ratio. The Ar multicharged ion beam current, impurity fraction and plasma parameters were measured. As a result, it was confirmed that the Ar multicharged ion yield was sufficient reproducibly increased by mixing He gas into Ar plasma. In addition, this from the measured plasma parameters is not an effect of the plasma parameters, but maybe a cooling effect.
High Performance 18 GHz ECR Ion Sources Development
Authors: Qian C , Sun L T , Lu W , Jia Z H , Yang T J , Zhu L , Zheng S J , Wang X D , Fang X , Li L B , Guo J W , Ma J D , Wang H , Feng Y C , Zhang X Z , Zhao H W
Published: April 2022

At present, ECR ion sources are developing towards higher frequency, higher magnetic field technology. However, 18 GHz is the highest optimal operation microwave frequency for room temperature ECR ion sources, which can meet the needs of most of the existing heavy ion facilities. After the success of the 18 GHz ECR ion source LECR4, we developed the upgraded version source LECR5 aiming for higher beam intensity and higher charge state ions. With a higher radial field, bigger plasma chamber volume, longer mirror length, and flexible Bmm field, promising results have been made at the power level of ∼2.1 kW@18 GHz, for instance, 81 eμA Bi32+, and 22 eμA Bi41+. This ion source has been recently used for the heavy ion facility SESRI (Space Environment Simulation Research Infrastructure) as the pre-injector ion source. High beam intensities and reasonable beam qualities have been demonstrated during the test platform. Inspired by this outcome, a hybrid 18 GHz ion source called HECRAL has been proposed aiming for the similar performance of SECRAL at 18 GHz. This paper will present the recent update of the LECR5 ion source commissioning. The design and preliminary results of the HECRAL ion source will be described.
Predictive fluid model for self-consistent description of inductive RF coupling in powerful negative hydrogen ion sources
Authors: Zielke D , Briefi S , Lishev S , Fantz U
Published: April 2022

RF-driven negative hydrogen ion sources are typically operated at low frequencies around 1 MHz, gas pressures around or below 1 Pa and large power densities up to 10 Wcm-3. Owing to these conditions as well as the current discharge geometries and antenna layouts, the RF power coupling is far from optimized, i.e. only a fraction η of the power delivered by the generator is absorbed by the plasma. This considerably limits the performance and reliability of RF-driven ion sources. To study the bidirectional RF power coupling a self-consistent fluid model is introduced. Taking into account the interplay between the nonlinear RF Lorentz force and the electron viscosity (usually neglected in state-of-the-art fluid models) a steady state solution is obtained, where the trends reflect the experimental data. Solutions calculated in hydrogen but with increased ion masses indicate that the latter are responsible for the systematically increased η, which is observed experimentally when deuterium instead of hydrogen is used as feed gas.
Ion source developments at IPP: On the road towards achieving the ITER-NBI targets and preparing concepts for DEMO
Authors: Fantz U , Briefi S , Fröschle M , den Harder N , Heiler A , Heinemann B , Hurlbatt A , Hopf C , Lindqvist M , Merk F , Mimo A , Nocentini R , Orozco G , Riedl R , Starnella G , Wimmer C , Wünderlich D , Yordanov D , Zielke D
Published: April 2022

The large ion source of ITER’s neutral beam injection (NBI) systems (0.9 m×1.9 m) with 1280 apertures has to deliver 57 A D- for 3600 s (286 A/m2) and 66 A H- for 1000 s (329 A/m2). The RF ion source test facilities ELISE and BUG at IPP are aimed to demonstrate the ion source parameters, the homogeneity of large beams (up to 1 m×1 m) and to perform beam optic studies. While the ITER parameters could be demonstrated in hydrogen, the achievement in deuterium for long pulses is still pending due to the large fraction of co-extracted electrons, their temporal dynamics, and inhomogeneity in vertical direction, limiting the ion source performance. Biasing of the bias plate in the vicinity of the plasma grid improves the symmetry of the co-extracted electrons and contributes to its stabilzation being thus a promising alternative to potential rods formerly used to achive high performance. With the replacement of the high-voltage power supply at ELISE first 100 s steady state extraction is demonstrated increasing the relevance of the test facility for ITER and DEMO studies. For the latter, the IPP contributions focus on improvement of the RF coupling, the caesium management and conceptual studies of a beam driven plasma neutraliser as alternative to the gas neutraliser system.
Overview of recent and upcoming activities at the BATMAN Upgrade test facility
Authors: Wimmer C. , Briefi S. , Fröschle M. , Heinemann B. , den Harder N. , Hurlbatt A. , Mimo A. , Nocentini R. , Orozco G. , Fantz U.
Published: April 2022

The BATMAN Upgrade (BUG) test facility at IPP is contributing to the development of RF-driven H- sources towards the ITER neutral beam injection and beyond. BUG is equipped with an 1/8 size of the ITER NBI ion source and thus is highly flexible for setup changes or diagnostic access. The present strategy for BUG is aligned along two paths: (i) BUG is continuing to be upgraded upgrading for long pulse operation (up to 1 hour, both in H and D) to identify measures for the stabilization of long pulses. For pulses > 100 s a cooling of the plasma grid (first grid of the extraction system) is required in order to avoid the dominance of thermal Cs desorption. A Cs evaporation concept with evaporation close to the extraction system is being tested, showing a stabilization of co-extracted electrons in 100 s H pulses, (ii) BUG is used for investigations of whole beam and beamlet optics for which the beam diagnostics have been massively upgraded. The beam diagnostics have been used to characterize a newly installed MITICA-like extraction system including asymmetric deflection compensation magnets.
Difference of co-extracted electron current and beam acceleration in a negative ion source with hydrogen-isotope ions
Authors: Ikeda K. , Tsumori K. , Nakano H. , Nagaoka K. , Takeiri Y. , Masaki S. , Rattanawongnara E. , Osakabe M.
Published: April 2022

Improvement of the performance on a hydrogen/deuterium negative ion source for a nuclear fusion device is reported. In particular, the suppression of the co-extracted electron current, Ie, is an important issue to ensure the stable beam acceleration. Improvement of the Ie
has been confirmed by optimizing the magnetic field of the electron deflection magnet in the extraction grid. Two other new methods for reduction of the Ie
were validated. The first was an electron fence whose rods were set between the rows of apertures on a plasma grid. The electron and negative ion current ratio, approximately Ie/I
acc, was greatly improved from 0.7 to 0.25 in deuterium. The second was an outer iron yoke which enhanced the magnetic flux density 19% inside the arc discharge chamber. The Ie/Iacc
using the outer yoke decreased by 0.1 compared with using a normal magnetic filter in a deuterium operation. These attempts have improved the total deuterium injection beam power of 8.4 MW by three negative ion based NBIs.
Optimization of ion transport in a combined RFQ Cooler with axial magnetic field
Authors: Cavenago M. , Romé M. , Maero G. , Bellan L. , Cavaliere F. , Comunian M. , Galatà A. , Maggiore M. , Panzeri N. , Pisent A. , Pranovi L. , Sattin M.
Published: April 2022

The accurate mass spectrometry (with resolution goal 1:20000) of exotic ions requests beams with low energy spread (goal is about 0.5 eVrms or lower) and low transverse emittance, so it is necessary to cool ions produced by a fission source. In a radiofrequency (rf) quadrupole cooler (RFQC), collisions decrease ion kinetic energy, while rf and DC voltages confine and reaccelerate ions towards the extraction, where the cold ion beam is formed. Operation is based on carefully chosen tunings of voltages and of gas pressure p
g, which requires an adequate pumping system; efficient simulations of extraction systems, which critically depend on residual speed of ions, are also important. Progresses in the experimental setup are described. Indications from simple ray tracing and ‘ray+collision’ tracing are compared. Results are applied to a simple triode extraction system, and more flexible configurations are considered.
Production of C-14 and stable ion beams at the Argonne Tandem Linac Accelerator System with the ECR3 ion source
Authors: Scott R H , McLain J , Vondrasek R C
Published: April 2022

The Argonne Tandem Linac Accelerator System (ATLAS) at Argonne National Laboratory (ANL) paused production of carbon-14 ion beams with the removal of the Tandem Van de Graaff in 2013. Installation of ECR3, an Electron Cyclotron Resonance Ion Source, returned that production capability to ATLAS, with the first C-14 beam delivered in December 2020. Information is presented on C-14 beam current, gas consumption and N-14 filtering techniques using stripping foils at different sections of ATLAS. ECR3 also fulfilled the operational goal of adding flexibility to ATLAS stable beam production capabilities. Beneficial impacts to ATLAS operation, beam development and experimental programs are discussed.
Anomalous Ionization Regime in a Forced Electron Beam Induced Arc Discharge Ion Source for Singly Charged Radioactive Ion Beam Production
Authors: Maldonado Millan F , Babcock C , Day Goodacre T , Gottberg A
Published: April 2022

At TRIUMF’s ISAC facility, 1+ Radioactive Ion Beams (RIBs) of noble gases, halogens, and molecules are created using a Forced Electron Beam Induced Arc Discharge (FEBIAD) ion source. Reported ionization efficiencies for FEBIADs range from 10% to 25% for 40Ar+, while TRIUMF-FEBIAD ionization efficiency seems to be < 1% with a 90% emittance <15 μm. As RIB ion sources aim for a high ionization efficiency, an experimental and numerical campaign was conducted to investigate the comparably low efficiencies observed. The experimental results for 40Ar+ indicate that up to a 10% ionization efficiency is possible by operating the source at different parameters. The measurements agree with theoretical estimations; however, certain combinations of parameters produce an anomalously high electron current which enhances the ionization efficiency threefold. Present investigations aim to characterize and model the anomalous electron current because, if proven reliable, the argon ionization efficiency could reach 30% with no significant impact on beam emittance.
Simulations of a new electron gun for the TITAN EBIT
Authors: Cardona J D , Dietrich K , Mukul I , Dilling J , Gwinner G , Kester O , Kwiatkowski A A
Published: April 2022

Penning trap mass spectrometry is the tool of choice for mass measurements to test the Standard Model or lay the nuclear-physics foundation of neutrino physics due to the high precisions achievable. This precision can be further boosted by higher charge states (Ettenauer et al 2011). For this purpose, an electron beam ion trap (EBIT) provides radioactive HCIs at the TITAN facility at TRIUMF. To improve the electron beam properties and its control, a new electron gun is under development. The electron gun within its TITAN EBIT environment was simulated using Field Precision’s TRAK software. A new electrode geometry was chosen and optimized to extract up to 5A, 66 keV electron beams. Due to the strong fringe field of the unshielded 6T magnet, options for the passive and active shielding of the gun were explored to compress the electron beam. During the design process, careful attention was paid to safety and mechanical considerations. Simulations and the status of the new electron gun will be presented.
Analysis of electron behaviour around a spring-shape filament inside a low-energy electron gun
Authors: Matsumoto Y , Nakano H , Kisaki M , Shinto K , Sasao M , Wada M
Published: April 2022

Electron behaviour inside a low-energy electron gun based on a spring-shape filament were studied with experiment and Particle-In-Cell simulation. The energy range of the electron beam which we expected was from 1 to 20 eV. The analysis told that smaller size of filament is more useful to improve electron density in front of an extraction hole in the gun to enhance beam current. Relation between a space potential distribution in the gun and electron transport was also studied. A heater voltage to drive a filament for thermionic electron emissions has another role to form a spatial potential distribution in the gun. The potential guides electrons, which are at a distant area from the beam extraction hole, toward the hole. It can be a significant help to realize efficient electron extraction by a beam extraction electric field induced near the hole.
A Low Energy Beam Transport to Match a Multicusp Ion Source to an RFQ
Authors: Waites Loyd , Conrad Janet , Winklehner Daniel
Published: April 2022

The RadioFrequency Quadrupole Direct Injection Project (RFQ-DIP) uses a filament-driven multicusp ion source to produce

H
2
+

. A Low Energy Beam Transport (LEBT) injects the beam from the ion source into the RFQ. The LEBT shapes the beam to the optimum input Twiss parameters for transmission through the RFQ while minimizing the emittance. The LEBT system has been designed using the accelerator codes IBSimu and Warp. To ensure the accuracy of the simulations, a series of diagnostic tools to assess the beam quality have been integrated into the LEBT design. The LEBT also integrates a beam chopper for machine protection and duty factor control, as well as steering capability to compensate for small misalignments. Presented here are the beam dynamics simulations and the design of the LEBT and matching to the RFQ.
Concept design of new compact electron cyclotron resonance ion source with permanent magnets for multi-ion radiotherapy
Authors: Muramatsu Masayuki , Ouchi Fumihisa , Suzuki Taku , Takahashi Katsuyuki , Sasano Toshinobu , Shiraishi Tadahiro , Nomura Shinji , Takahashi Nobuaki , Kato Yushi , Katagiri Ken , Mizushima Kota , Iwata Yoshiyuki , Inaniwa Taku , Kitagawa Atsushi
Published: April 2022

The multi-ion radiotherapy with dose distribution and Liner Energy Transfer optimization is being studied at QST. Helium, carbon, oxygen and neon ions are considered as ion species for multi-ion therapy. A basic experiment using these ion beams has been carried out at the HIMAC. For heavy-ion radiotherapy facility, it is desirable to operate with only one ECR ion source with permanent magnets from the viewpoint of cost and maintenance. We considered the operating method with only one ion source for multi-ion radiotherapy. Ionization gases were helium, methane, oxygen, and neon to produce He2+, C4+, O6+ and Ne7+ ions. Requirement values of beam current were 940 μA correspond to He2+, 290 μA to C4+, 330 μA to O6+, and 245 μA to Ne7+, respectively. This value was obtained from the number of particles required for the cancer treatment and the transmission efficiency of the accelerator in the HIMAC. We performed some beam tests for design of a new compact ion source with the existing 18 GHz ECR ion source (NIRS-HEC). From the results of the beam tests, we estimate the mirror magnetic field of NIRS-HEC by using POISSON/SUPERFISH code. Then, the structure of the permanent magnets for new ECR ion source is determined so that they reproduce the values of the upstream mirror peak (Binj), B minimum (Bmin) and the downstream mirror peak (Bext) at the NIRS-HEC. The magnetic field of Binj, Bmin and Bext at NIRS-HEC were 1.14 T, 0.475 T and 0.9 T, respectively.
Dynamics and reactivity of thermalized ions in a radiofrequency quadrupole gas-reaction cell used for the production of radioactive molecular ions
Authors: Alary J-F , Cousins L M , Javahery R , Kieser W E , Flannigan E L , Charles C
Published: April 2022

Two-dimensional radiofrequency quadrupole (RFQ) ion guides are versatile tools that are used over a wide range of ion energies. Properly tuned, they can provide an ideal environment for ion-molecule chemistry to proceed by allowing thermalized ions to react on-line with gaseous reactants. We exploit this capability in the Ion Reaction Cell (IRC), an RFQ-based system designed to form radioactive molecules (RM) from radioactive ion beams (RIB). Functionally, the IRC accepts RIB produced upstream by the isotope separation on-line (ISOL) method, decelerates it to eV energies for production of the RM and then re-accelerates RM to their incident energy. This system promises to form a highly versatile source of complex inorganic or organic RM that can be used in fundamental symmetry studies or as precursors to new radiopharmaceuticals. We discuss the challenges of transferring ions from a RIB into a gas cell at room temperature while constraining ions within the RFQ energy well, and of reforming a beam from synthesized RM. Various factors influencing ion dynamics and reactivity in thermal and non-thermal zones inside the IRC are considered, using results obtained recently with the Isobar Separator for Anions, an analogous RFQ technique used in Accelerator Mass Spectrometry, to illustrate key points.
Research on collaborative planning of distributed resources and energy storage in regional integrated energy system
Authors: Ma Zhoujun , Zhang Yong
Published: April 2022

Aiming at the problem of high operation cost caused by low energy utilization of users in the region, a collaborative planning method of distributed resources and energy storage of regional integrated energy system is proposed. We designed the operation framework of the regional integrated energy system, and described the operation state of the equipment and the energy coupling relationship. According to the relationship between cooling, heating and power supply, the objective function is established with the lowest total operating cost, the highest reliability and the highest system emission reduction rate, and the control constraints are established for the total load in the system. We have established a collaborative ownership model for distributed resources and energy storage, and distributed energy supply and energy storage equipment in the system. It enables each energy supply and energy storage device to adjust the operating mode according to its own needs. So as to realize the reasonable supply of energy and the economical and optimal operation of all users. Taking three typical users in a park as an example, the results show that the operating costs of the three users are reduced by 15532.92 yuan, 5906.63 yuan and 24495.62 yuan respectively. The planning method can not only ensure the stable operation of the energy system, but also reduce the operation cost of users.
Numerical simulation of liquid-liquid heat pipe heat exchanger applied as sampling cooler in nuclear power
Authors: Liu Mengmeng , Tao Hanzhong
Published: April 2022

Monitoring and control of the temperature and pressure of water sample are critical issues in the nuclear power engineering for the efficient and safe operation. In this paper, through the thermal and fluid dynamical simulations, we demonstrated the improvement in heat transfer performance of the heat pipes used in the sampling cooler by changing the heat pipe diameters and the fin types. Heat pipes with helical fins show a 30.9% enhancement in heat transfer j factor compared to the smooth heat pipes. Additionally, the numerical results also show that the sampling cooler has an optimal helical fin pitch, which is 140mm.
Multi-objective Control Optimization of Pumped Storage Units under Successive Load Rejections
Authors: Lai Xinjie , Huang Huimin , Zheng Bo , Wu Yuechao , Luo Yuanlin
Published: April 2022

Pumped hydropower is one of the most important renewable energy in a power grid, which is converted into electricity through pumped storage hydropower systems (PSHS). However, the energy conversion process of a PSHS may be greatly threatened by extreme working conditions, especially successive load rejections (SLR). In order to obtain the optimal control scheme for SLR, this paper aims to study the control optimization strategies so as to achieve safe and stable operation of PSHS. Firstly, a refined nonlinear PSHS model for SLR is constructed and validated by field data. Then, a novel optimization strategy incorporating multiple objectives, multiple guide vane control law (GVCL) schemes and multiple engineering constraints are proposed. The result shows that the proposed optimization strategy is effective for solving the control problem of PSHS under SLR, the optimal GVCL for SLR can be obtained by only one optimization.
Manufacturing process optimization and quality grading method of insulating paperboard for converter transformer
Authors: Zhang Shuqi , Yu Xinru , Wu Chao , Jia Pengfei , Deng Junyu , Cheng Huanchao
Published: April 2022

Oil paper insulation is the main form of transformer internal insulation. Different from the conventional transformer, the insulating paperboard bears a higher electric field component in the interior of the converter transformer. Therefore, the performance of insulating paperboard plays a vital role in the reliability of converter operation. Many insulation faults have occurred in the operation of UHV converter transformer. The production process and detection standard of conventional transformer insulating paperboard can not meet the operation requirements of UHV converter transformer under high field strength. In this study, the performance of insulating paperboard for UHV converter transformer was tested and compared. Combined with the series tests of micro properties, physical and chemical properties and electrical properties in the manufacturing process of insulating paperboard, the key manufacturing process of insulating paperboard is studied, and the process measures suitable for UHV converter transformer insulating paperboard are put forward. In addition, the comparison between the current test standard of insulating paperboard and the actual operation requirements is carried out, and the key performance test indexes of insulating paperboard applicable to converter transformer that are not covered in IEC standard are analyzed. The quality classification of insulating paperboard of UHV converter transformer and conventional transformer is carried out, and the selection scheme is provided. Insulating paperboard of class A is selected to be suitable for the design and manufacture of UHV converter transformer. The research results provide support for improving the performance of insulating paperboard of UHV converter transformer and ensuring the operation reliability of transformer.
An Optimal Design of a Fire Pump with Protection Function
Authors: Peng Ziyu , Duan Yitong , He Kun
Published: April 2022

At present, the existing power mechanical gasoline engine fire pump is prone to large vibration during operation. Due to the lack of protection structure, long-term vibration will shorten the service life of the fire pump. Meanwhile, the upper end of the fire pump body is usually not set up with a protective structure, which is easily damaged by the extrusion and impact of objects. Therefore, a new type of protection device is designed in this paper, which plays a protective role by setting a relevant absorber at the lower end of the fire pump body, and at the same time, a buffer pad is arranged at the upper end of the cover to have the effect of buffering and shock absorption. To this end, this device has the function of reducing the damage to the fire pump body caused by the impact of heavy objects, improving the performance of the existing fire pump, and prolonging its service life.
Study of the adsorptive removal of (Fe+2) and (Ni+2) from water by synthesized magnetite/corn cobs magnetic nanocomposite
Authors: Sanad Mohamed N , El-Dek S I , Eldemerdash Usama , ElFaham Mohamed M
Published: April 2022

Heavy metals are principal concomitant pollutants in industrial wastewaters, posing a serious threat to public health and the environment. Herein, we develop a novel strategy to produce a new nanocomposite formed from corn cobs (CCs) and magnetite as a nanomaterial for the simultaneous removal of Fe+2 and Ni+2. The as-prepared nanocomposite was systematically characterized by x-ray diffraction, field emission scanning electron microscopy, mapping, energy-dispersive x-ray spectroscopy, high-resolution transmission electron microscopy, selected area electron diffraction, zeta size, and zeta potential. Compared to the CCs and Fe3O4, the nanocomposite showed better adsorption performance. The maximum adsorption efficiency of the CC, Fe3O4, and the nanocomposite was calculated by atomic analysis to be around 91.84%, 91.28%, and 98.51%, respectively, under the same conditions. This study indicates that the nanocomposite could be a favorable biomass-derived adsorbent for the simultaneous removal of heavy metals.
The inductive McKay–Navarro conditions for the prime 2 and some groups of Lie type
Authors: Ruhstorfer L. , Schaeffer Fry A.
Published: April 2022

For a prime

ℓ
\ell

, the McKay conjecture suggests a bijection between the set of irreducible characters of a finite group with

ℓ
′

\ell ’

-degree and the corresponding set for the normalizer of a Sylow

ℓ
\ell

-subgroup. Navarro’s refinement suggests that the values of the characters on either side of this bijection should also be related, proposing that the bijection commutes with certain Galois automorphisms. Recently, Navarro–Späth–Vallejo have reduced the McKay–Navarro conjecture to certain “inductive” conditions on finite simple groups. We prove that these inductive McKay–Navarro (also called the inductive Galois–McKay) conditions hold for the prime

ℓ
=
2

\ell =2

for several groups of Lie type, namely the untwisted groups without non-trivial graph automorphisms.
An Algorithmic Approach to Managing Parotid Duct Injury Following Buccal Fat Pad Removal
Authors: Weissler Jason M , Mohamed Omar , Gryskiewicz Joseph M , Chopra Karan
Published: April 2022

The principles of achieving an aesthetically pleasing and harmonious facial appearance are influenced by our evolving understanding of the three-dimensional topography of the face coupled with novel approaches to midface volumization and contouring. In parallel with the evolving landscape of facial aesthetic surgery, an increasing number of publications have emerged focusing on the role of intraoral buccal fat pad removal (BFPR) for the purposes of aesthetic midface contouring. The authors sought to emphasize an underreported and potentially preventable and untoward complication involving iatrogenic parotid duct injury following BFPR. The purpose of this publication is 3-fold: (1) to review the relevant anatomy and literature on intraoral BFPR, (2) to present a case example of this complication, and (3) to discuss treatment options as part of a proposed management algorithm. The authors detail the surgical indications for performing BFPR and review the relevant anatomic considerations. Complication prevention strategies are outlined, and details regarding avoidance of parotid duct injury are reviewed. The diagnostic criteria and clinical presentation of parotid duct injuries following BFPR are comprehensively outlined. The authors present a clinically actionable algorithm for managing a suspected or diagnosed parotid duct injury following BFPR. A clinical case example is discussed to highlight this complication, the diagnostic criteria, and the systematic and algorithmic approach to management. Intraoral BFPR is an incredibly valuable and powerful procedure that can improve facial contour in patients with buccal lipodystrophy or buccal fat pad pseudoherniation. The authors propose a proper diagnostic approach and treatment algorithm to manage this untoward complication.

Level of Evidence: 5
Benchmarking of long-read sequencing, assemblers and polishers for yeast genome
Authors: Zhang Xue , Liu Chen-Guang , Yang Shi-Hui , Wang Xia , Bai Feng-Wu , Wang Zhuo
Published: April 2022

Background

The long reads of the third-generation sequencing significantly benefit the quality of the de novo genome assembly. However, its relatively high single-base error rate has been criticized. Currently, sequencing accuracy and throughput continue to improve, and many advanced tools are constantly emerging. PacBio HiFi sequencing and Oxford Nanopore Technologies (ONT) PromethION are two up-to-date platforms with low error rates and ultralong high-throughput reads. Therefore, it is urgently needed to select the appropriate sequencing platforms, depths and genome assembly tools for high-quality genomes in the era of explosive data production.

Methods

We performed 455 (7 assemblers with 4 polishing pipelines or without polishing on 13 subsets with different depths) and 88 (4 assemblers with or without polishing on 11 subsets with different depths) de novo assemblies of Yeast S288C on high-coverage ONT and HiFi datasets, respectively. The assembly quality was evaluated by Quality Assessment Tool (QUAST), Benchmarking Universal Single-Copy Orthologs (BUSCO) and the newly proposed Comprehensive_score (C_score). In addition, we applied four preferable pipelines to assemble the genome of nonreference yeast strains.

Results

The assembler plays an essential role in genome construction, especially for low-depth datasets. For ONT datasets, Flye is superior to other tools through C_score evaluation. Polishing by Pilon and Medaka improve accuracy and continuity of the preassemblies, respectively, and their combination pipeline worked well in most quality metrics. For HiFi datasets, Flye and NextDenovo performed better than other tools, and polishing is also necessary. Enough data depth is required for high-quality genome construction by ONT (>80X) and HiFi (>20X) datasets.
circRIP: an accurate tool for identifying circRNA–RBP interactions
Authors: Dong Xin , Chen Ke , Chen Wenbo , Wang Jun , Chang Liuping , Deng Jin , Wei Lei , Han Leng , Huang Chunhua , He Chunjiang
Published: April 2022

Circular ribonucleic acids (RNAs) (circRNAs) are formed by covalently linking the downstream splice donor and the upstream splice acceptor. One of the most important functions of circRNAs is mainly exerted through binding RNA-binding proteins (RBPs). However, there is no efficient algorithm for identifying genome-wide circRNA–RBP interactions. Here, we developed a unique algorithm, circRIP, for identifying circRNA–RBP interactions from RNA immunoprecipitation sequencing (RIP-Seq) data. A simulation test demonstrated the sensitivity and specificity of circRIP. By applying circRIP, we identified 95 IGF2BP3-binding circRNAs based on the IGF2BP3 RIP-Seq dataset. We further identified 2823 and 1333 circRNAs binding to >100 RBPs in K562 and HepG2 cell lines, respectively, based on enhanced cross-linking immunoprecipitation (eCLIP) data, demonstrating the significance to survey the potential interactions between circRNAs and RBPs. In this study, we provide an accurate and sensitive tool, circRIP (https://github.com/bioinfolabwhu/circRIP), to systematically identify RBP and circRNA interactions from RIP-Seq and eCLIP data, which can significantly benefit the research community for the functional exploration of circRNAs.
TRamWAy: mapping physical properties of individual biomolecule random motion in large-scale single-particle tracking experiments
Authors: Laurent François , Verdier Hippolyte , Duval Maxime , Serov Alexander , Vestergaard Christian L , Masson Jean-Baptiste
Published: April 2022

Motivation

Single-molecule localization microscopy allows studying the dynamics of biomolecules in cells and resolving the biophysical properties of the molecules and their environment underlying cellular function. With the continuously growing amount of data produced by individual experiments, the computational cost of quantifying these properties is increasingly becoming the bottleneck of single-molecule analysis. Mining these data requires an integrated and efficient analysis toolbox.

Results

We introduce TRamWAy, a modular Python library that features: (i) a conservative tracking procedure for localization data, (ii) a range of sampling techniques for meshing the spatio-temporal support of the data, (iii) computationally efficient solvers for inverse models, with the option of plugging in user-defined functions and (iv) a collection of analysis tools and a simple web-based interface.

Availability and implementation

TRamWAy is a Python library and can be installed with pip and conda. The source code is available at https://github.com/DecBayComp/TRamWAy.
SpatialExperiment: infrastructure for spatially-resolved transcriptomics data in R using Bioconductor
Authors: Righelli Dario , Weber Lukas M , Crowell Helena L , Pardo Brenda , Collado-Torres Leonardo , Ghazanfar Shila , Lun Aaron T L , Hicks Stephanie C , Risso Davide
Published: April 2022

SpatialExperiment is a new data infrastructure for storing and accessing spatially-resolved transcriptomics data, implemented within the R/Bioconductor framework, which provides advantages of modularity, interoperability, standardized operations and comprehensive documentation. Here, we demonstrate the structure and user interface with examples from the 10x Genomics Visium and seqFISH platforms, and provide access to example datasets and visualization tools in the STexampleData, TENxVisiumData and ggspavis packages.

Availability and implementation

The SpatialExperiment, STexampleData, TENxVisiumData and ggspavis packages are available from Bioconductor. The package versions described in this manuscript are available in Bioconductor version 3.15 onwards.

Supplementary information

Supplementary data are available at Bioinformatics online.
GEInfo: an R package for gene–environment interaction analysis incorporating prior information
Authors: Wang Xiaoyan , Liu Hongduo , Ma Shuangge
Published: April 2022

Gene–environment (G–E) interactions have important implications for many complex diseases. With higher dimensionality and weaker signals, G–E interaction analysis is more challenged than the analysis of main G (and E) effects. The accumulation of published literature makes it possible to borrow strength from prior information and improve analysis. In a recent study, a ‘quasi-likelihood + penalization’ approach was developed to effectively incorporate prior information. Here, we first extend it to linear, logistic and Poisson regressions. Such models are much more popular in practice. More importantly, we develop the R package GEInfo, which realizes this approach in a user-friendly manner. To facilitate direct comparison and routine data analysis, the package also includes functions for alternative methods and visualization.

Availability and implementation

The package is available at https://CRAN.R-project.org/package=GEInfo.

Supplementary information

Supplementary materials are available at Bioinformatics online.