bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling of Residual Stress Distribution for Components Manufactured by Selective Laser Melting
Authors: Ye Tong , Jiang Xiaohui , Guo Miaoxian , Kuptsov Vladimir , Fedorov Sergey
Published: December 2019

In this paper, the selective laser melting (SLM) simulation analysis of components is carried out. The residual stress distribution of the formed part was predicted, and the influence of process parameters such as exposure time, laser power and laser scanning speed on the residual stress of the SLM formed part was analyzed. It was found that the residual stress concentration of the formed part was in the middle of the upper surface or the bottom surface. In addition, the laser power and the laser scanning speed have a great influence on the residual stress of the formed part. The results of this study lay a theoretical and experimental basis for the optimization of residual stress and quality control of SLM components.
Stability Analysis of Centerless Grinding with Loss of Contact Nonlinearity
Authors: Leonesio Marco , Bianchi Giacomo , Safarzadeh Hossein
Published: December 2019

The paper presents a novel geometrical stability analysis of centerless grinding that takes into account the nonlinearity associated to wheel-workpiece detachment during lobes formation. Even though the rounding mechanism in centerless grinding has been studied since more than fifty years, stability analysis has been carried out applying stability criteria for linear systems (e.g., Nyquist) on a process model that neglects actual removal “clipping” due to wheel-workpiece detachment. This model limitation is usually overcome by considering only an integer number of lobes, supporting the restriction by the claim that a non-integral number of waves is less likely to build up since the waviness must be constantly removed and replaced by a succeeding wave, which is constantly moving around the workpiece. In this work, the nonlinearity entailed by removal clipping is explicitly taken into account and, by harmonic linearization, represented by a double input describing function (DIDF). Applying the Nyquist criterion on the resulting equivalent delayed system, the paramount instability associated to a quasi-integer number of lobes emerges naturally, without requiring additional assumptions. Moreover, it is shown that the nonlinearity due to wheel-workpiece detachment does not produce a limit cycle in a reasonable operation time. The results delivered by the proposed approach are verified by numeric simulations and positively compared to the relevant literature. The proposed formulation can be easily extended to consider also machine structure dynamics, thus increasing, even in this case, the accuracy of the stability analysis provided by the standard approach.
Effects of Milling Parameters on Distribution of Residual Stress During the Milling of Curved Thin-Walled Parts
Authors: Kong Xiangjing , Ding Zishan , Xu Lijun , Zhu Lijian , Zhang Jian , Wu Chongjun , Isaev Alexander
Published: December 2019

With the increasing application of curved thin-walled parts, the evaluation and control of curved surface residual stress in milling are becoming increasingly demanding. However, effects of milling parameters on distribution of residual stress remains a major challenge in the present aerospace research areas. In this paper, , impacts of milling parameters on curved surface residual stress have been investigated in a series of residual stress experiments and simulations. It is found that the residual stress can be lowered by increasing milling speed and tool radius within a reasonable range. The superposition of curved surface residual stress under two machining conditions have been analyzed using the milling simulation model. It has been found that the curved surface residual stress induced by the subsequent cutting will be superimposed on the curved surface residual stress induced by the previous cutting and that the superposition rates of residual stress induced by up milling are larger than down milling.
Influence of Thickness of Multilayer Composite Nano-structured Coatings on Tool Life of Metal-Cutting Tool
Authors: Sotova Catherine , Sitnikov Nikolay , Bublikov Jury , Oganyan Gaik , Batako Andre D.L.
Published: December 2019

The paper is focused on turning of structural steels C45. Cutting tools were represented by carbide cutting inserts without coatings, with reference coating TiAlN, as well as with multilayered composite nano-structured coatings Ti-TiN-(TiCrAl)N and Zr-ZrN-(ZrCrNbAl)N (of different thickness of 3-7 μm). The following studies of the properties of coated tools were carried out: measurement of microhardness and strength of adhesion bonds in the “tool-coating” system and investigation of elemental and phase compositions of coatings. The cutting tests were carried out at the following cutting modes: f = 0.2 mm/rev; аp = 1.0 mm; vc = 200, 250, 300, 350 and 400 m/min.
Simulation System of Technological Support of Automated Complex
Authors: Oleynik A.V. , Kuznetsova L.V. , Nikolaev A.V. , Kuznetsov L.Yu. , Dimitrov M.
Published: December 2019

Mathematical modeling of technical and technological systems and processes occurring in these systems can be interpreted as multi-step processes of solving managerial problems, where the application of classical methods for obtaining numerical results is possible. In particular, it is practical to apply the theory of dynamic programming based on the use of functional equations and the optimality principle to solve the problem of resource allocation. In the formulation and solution of the dynamic programming problem, the process is divided into stages in time, and at each stage decisions at which the goal is achieved are made. In our case, homogeneous stages are considered, and the use of the optimality principle leads to the fact that a decision made at each stage is the best regarding the entire process.
Verification of the Returns to Scale of Production Type for the Russian Federation Regions
Authors: Kirilyuk Igor , Senko Oleg
Published: December 2019

Monte-Carlo methods to asses a statistical validity of the relationship between coefficients of time series regression model were proposed. In economics such a relationship is present in the case when constant return to scale in production functions is assumed. The techniques being discussed here are virtually free from assumptions about underlying probability distributions and may be used in the case, when target variable or regressors are time series with random walk. This is achieved by comparing the regression model built on truly multivariate time series with those built on simulated time series with random walk. It has been shown that for the production functions of most Russian regions, the returns to scale significantly differs from a constant value at p<0.05.
Ein Leben für die Gesundheit der Armen: Laudatio für Prof. Dr. med. Gerhard Trabert anlässlich der Verleihung der Salomon-Neumann-Medaille
Authors: Huber Ellis
Published: December 2019

Die Deutsche Gesellschaft für Sozialmedizin und Prävention (DGSMP) verleiht die Salomon-Neumann-Medaille für besondere Verdienste um die Präventiv- und Sozialmedizin. Die Salomon Neumann-Medaille 2019 wurde an Gerhard Trabert, Gründer und 1. Vorsitzender des Vereins „Armut und Gesundheit in Deutschland“ und Professor für Sozialmedizin und Sozialpsychiatrie an der Hochschule RheinMain in Wiesbaden verliehen. Sie ehrt einen Sozialmediziner, in dessen Person und Wirken als „Armenarzt unserer Zeit“ in besonderer Weise zum 200. Geburtstag des Namensgebers das sozialpolitische Engagement Salomon Neumanns für unsere Zeit aktualisiert sichtbar wird.
Endoscopic ultrasound and fine-needle aspiration for the detection of residual nodal disease after neoadjuvant chemoradiotherapy for esophageal cancer
Authors: van der Bogt Ruben D. , van der Wilk Berend J. , Poley Jan-Werner , Krishnadath Kausilia K. , Schoon Erik J. , Oostenbrug Liekele E. , Siersema Peter D. , Vleggaar Frank P. , Bruno Marco J. , Biermann Katharina , van Lanschot J. Jan B. , Spaander Manon C. W.
Published: December 2019

Background Endoscopic ultrasound (EUS) and fine-needle aspiration (FNA) are potential tools for the detection of residual disease after neoadjuvant chemoradiotherapy (nCRT) for esophageal cancer. This study investigated yield of EUS and FNA for detection of malignant lymph nodes (LNs) after nCRT.

Methods This was a post hoc analysis of the preSANO trial. EUS was performed 10 – 12 weeks after nCRT. 18F-fluorodeoxyglucose positron emission tomography – computed tomography (18F-FDG PET-CT) was used to guide targeting of suspicious LNs. Consecutive FNA sampling was performed for suspicious LNs identified on EUS and/or PET-CT. EUS nodal staging was compared with histopathological examination of the resection specimen. The primary outcome was the proportion of correctly identified patients with malignant LNs by radial EUS.

Results 101 consecutive patients were included: 79 patients had no malignant LNs, of whom 62 were classified correctly by EUS (specificity 78 %); 22 patients had malignant LNs, of whom 11 were identified (sensitivity 50 %). Six of these patients had ≥ 1 suspicious LN not fulfilling EUS criteria (round, hypoechogenic, > 5 mm). Malignant LNs in falsely negative patients were predominantly located at distal LN stations. Specificity and sensitivity of conclusive FNA outcomes were 100 % (7/7) and 75 % (3/4), respectively. FNA outcome was uncertain in eight patients, half of whom appeared to have malignant LNs.

Conclusions EUS only detected 50 % of patients with malignant LNs 10 – 12 weeks after nCRT. To optimize sensitivity and minimize the risk of missing residual disease, FNA of LNs should be performed even in cases of low endosonographic suspicion.
Carotid Body Baroreceptor Preservation and Control of Arterial Pressure in Eversion Carotid Endarterectomy
Authors: Kotsis Thomas , Christoforou Panagitsa , Nastos Konstantinos
Published: December 2019

The technique of the eversion carotid endarterectomy (ECEA), as an alternative to the conventional endarterectomy with primary or patch angioplasty, is an established technique for managing internal carotid artery stenoses and recently its application has been upgraded through the European Society for Vascular Surgery guidelines (Recommendation 55: Class 1, Level A). However, the typical eversion method has been associated with postoperative hypertension due to loss of the baroreceptor reflex; the standard oblique transection at the bulb performed in the eversion endarterectomy interrupts either the baroreceptor sensoring tissue, which is mostly located in the adventitia at the medial portion of the proximal internal carotid artery, or even the proper Hering nerve, a branch of the glossopharyngeal nerve. These actions deregulate the natural negative feedback of the carotid baroreceptor. Guided by the anatomical location of the baroreceptor sensor we have elaborated a slight modification of the classical ECEA to maintain as much as possible of the viable carotid baroreceptor sensoring surface. By extending the oblique incision distal to the carotid bifurcation in the medial part of the internal carotid artery stem, an eyebrow-like part of the proximal internal carotid artery is maintained and the axis from the sensoring tissue to the nerve of Hering is protected and following the endarterectomy, postoperative arterial blood pressure levels are lower than in the classical ECEA due to the maintenance of the efficiency of the baroreceptor reflex. During the period from September 2016 to November 2018, carotid endarterectomy was performed in 57 patients. Twenty-eight of them underwent the typical ECEA and 29 patients had the modified eyebrow eversion carotid endarterectomy (me-ECEA). The changes of blood pressure baseline during the postoperative course in ECEA and me-ECEA group were analyzed and compared. Postoperative hypertension was defined as an elevation of systolic blood pressure (SBP) greater than 140 mm Hg. Patients who underwent typical ECEA had significantly higher postoperative blood pressure values compared with those who underwent me-ECEA. Actually, the mean postoperative SBP was 172.67 ± 24.59 mm Hg in the typical ECEA group compared with 160.86 ± 12.83 mm Hg in the me-ECEA group (p = 0.023). The mean diastolic blood pressure in the ECEA group was 65.42 ± 11.39 mm Hg compared with 58.06 ± 9.06 mm Hg in the me-ECEA group (p = 0.009). Our proposed me-ECEA technique seems to be related to lower rates of postoperative hypertension compared with the typical ECEA, probably due to the sparing of the main mass of the baroreceptor apparatus; this improved modification (me-ECEA) of the typical eversion procedure could represent an alternative ECEA technique with its inherent advantages.
An experimental study of a multi-orifice synthetic jet with application to cooling of compact devices
Authors: Yadav Harekrishna , Joshi Ajinkya , Chaudhari Mangesh , Agrawal Amit
Published: December 2019

In the present work, the flow characteristics of free and impinging synthetic jets formed from a single cavity but with a different number of orifices are investigated using the particle image velocimetry technique. A synthetic jet is a zero-net mass-flux device that formed by periodic ejection and suction of fluid through a small opening. The flow characteristics are used to explain the heat transfer results in the literature. The number of satellite orifices, distance between orifices, and location of the surface from orifices are varied to observe the phenomenon of jet interaction and its influence on flow recirculation. The results show that interaction between adjacent jets causes the diversified flow characteristics of the multiorifice jet with respect to a single orifice jet. The multiorifice jet exhibits significantly higher entrainment and mixing compared to its equivalent diameter of a single orifice jet. Moreover, results from the impinging jet corroborate that the impingement of vortex pairs, their breakdown, and formation of a strong wall jet are responsible for a high heat transfer coefficient for the case of larger surface spacing (z/d ≥ 8; normalized distance between orifice and surface). However, for impingement at small surface spacing (z/d ≤ 2), change in recirculation behavior with different orifice configurations can lead to a variation in the heat transfer coefficient. For the large and medium surface spacing (2 < z/d < 8), the center orifice gets sufficient time to develop, which draws the satellite and impingement jets as a single orifice jet. In the case of large surface spacing, the wall jet vortices are not attracted during the suction stroke. While for medium surface spacing, wall jet vortices are closer to the orifice and easily entrained during the suction stroke and form a recirculating region. In the case of small surface spacing, the center jet does not get sufficient time, and hence both center and satellite jets impinge separately. It was found that the center jet having higher ejection velocity impinges earlier than the satellite jet and the wall jet vortex formed from the center orifice drives along a wall jet. Therefore, recirculation is absent for smaller surface spacing, and fresh fluid is sucked and impinges on the surface in each cycle. This study expands the current knowledge of multiorifice free and impinging jets and establishes a relationship between heat transfer and fluid flow, which eventually facilitates an efficient and effective heat transfer system for compact devices.
Assembly of Three Lanthanide Coordination Polymers from 2-(4-Carboxybenzyloxy) Benzoic Acid Ligand: Synthesis, Structure, and Fluorescent Properties
Authors: Wang Shu-Ju , Jiang Yi-Hui , Wu Han-Lin , You Li-Xin , Xiong Gang , Ding Fu , Sun Ya-Guang
Published: December 2019

Three new coordination polymers, {[Ln(cbb)(Hcbb)(DMF)·H2O]n, Ln=Sm (1), Eu (2), Tb(3), H2cbb=2-(4-carboxybenzyloxy) benzoic acid, DMF=N,N-dimethylformamide}, have been synthesised by a solvothermal reaction and structurally characterised by infrared spectroscopy, elemental analysis, thermogravimetry analysis, and X-ray single-crystal diffraction. The results of single-crystal X-ray diffraction indicate that the coordination polymers 1–3 are isostructural, belong to a triclinic system, space group P-1, and show 1D chain structures through the H2cbb ligands connecting adjacent lanthanide ions. In addition, the fluorescence properties of polymers 1–3 were also investigated.
Lipid remodelling plays an important role in wheat (Triticum aestivum) hypoxia stress
Authors: Xu Le , Pan Rui , Zhou Meixue , Xu Yanhao , Zhang Wenying
Published: December 2019

Membrane lipid remodelling is one of the strategies that plants have developed to combat abiotic stress. In this study, physiological, lipidomic and proteome analyses were conducted to investigate the changes in glycerolipid and phospholipid concentrations in the wheat (Triticum aestivum L.) cultivars CIGM90.863 and Seri M82 under hypoxia treatment. The growth of CIGM90.863 remained unaffected, whereas Seri M82 was significantly stunted after 8 days of hypoxia treatment. The concentrations of all lipids except lysophosphatidylglycerol were significantly higher in the leaves of Seri M82 than in CIGM90.863 under normal growth conditions. The lipid profile changed significantly under hypoxia stress and varied between genotypes for some of the lipids. Phosphatidic acids remained unchanged in Seri M82 but they were gradually induced in CIGM90.863 in response to hypoxia stress because of the higher phospholipase D expression and lower expression of diglycerol kinase and phosphatidate phosphatases. In contrast, digalactosyldiacylglycerol content was highly stable in CIGM90.863 following hypoxia treatment, although it decreased significantly in Seri M82. Phosphatidylglycerol and lipoxygenase showed a stronger and faster response in CIGM90.863 than in Seri M82 under hypoxia stress. Different membrane lipid adjustments in wheat under oxygen deficiency conditions could be partly responsible for the differing tolerance of Seri M82 and CIGM90.863. This study will help us to better understand how wheat tolerates hypoxia stress by regulating lipid remodelling.
Benchmarking PBE+D3 and SCAN+rVV10 methods using potential energy surfaces generated with MP2+ΔCCSD(T) calculation
Authors: Chen Jie , Xie Weiyu , Li Kaihang , Zhang Shengbai , Sun Yi-Yang
Published: December 2019

We develop a benchmark system for van der Waals interactions obtained with MP2+ΔCCSD(T) method at complete basis set limit. With this benchmark, we examine the widely used PBE+D3 method and recently developed SCAN+rVV10 method for density functional theory calculations. Our benchmark is based on two molecules: glycine (or Gly, an amino acid) and uracil (or U, an RNA base). We consider six dimer configurations of the two monomers and their potential energy surfaces as a function of relative distance and rotation angle. The Gly-Gly, Gly-U, and U-U pairs represent London dispersion, hydrogen bonding, and π–π stacking interactions, respectively. Our results show that both PBE+D3 and SCAN+rVV10 methods can yield accuracy better than 1 kcal/mol, except for the cases when the distance between the two monomers is significantly smaller than the equilibrium distance. In such a case, neither of these methods can yield uniformly accurate results for all the configurations. In addition, it is found that the SCAN and SCAN+rVV10 methods can reproduce some subtle features in a rotational potential energy curve, while the PBE, PBE+D3, and the local density approximation fail.
Giant topological Hall effect of ferromagnetic kagome metal Fe3Sn2*
Authors: Wang Qi , Yin Qiangwei , Lei Hechang
Published: December 2019

We present the experiment observation of a giant topological Hall effect (THE) in a frustrated kagome bilayer magnet Fe3Sn2. The negative topologically Hall resistivity appears when the field is below 1.3 T and it increases with increasing temperature up to 300 K. Its maximum absolute value reaches ∼ 2.01 µΩ·cm at 300 K and 0.76 T. The origins of the observed giant THE can be attributed to the coexistence of the field-induced skyrmion state and the non-collinear spin configuration, possibly related to the magnetic frustration interaction in Fe3Sn2.
Machine Protection Experience from Beam Tests with Crab Cavity Prototypes in the CERN SPS
Authors: Lindstrom B , Bartosik H , Bohl T , Butterworth A , Calaga R , Carver L R , Kain V , Levens T E , Papotti G , Secondo R , Uythoven J , Valette M , Vandoni G , Wenninger J , Wollmann D , Zerlauth M
Published: December 2019

Crab cavities (CCs) constitute a key component of the High Luminosity LHC (HL-LHC) project. In case of a failure, they can induce significant transverse beam offsets within tens of microseconds, necessitating a fast removal of the circulating beam to avoid damage to accelerator components due to losses from the displaced beam halo. In preparation for the final design to be employed in the LHC, a series of tests were conducted on prototype crab cavities installed in the Super Proton Synchrotron (SPS) at CERN. This paper summarizes the machine protection requirements and observations during the first tests of crab cavities with proton beams in the SPS. In addition, the machine protection implications for future SPS tests and for the use of such equipment in the HL-LHC are discussed.
Low Emittance Tuning of FCC-ee
Authors: Charles T.K. , Aumon S. , Holzer B. , Oide K. , Zimmermann F.
Published: December 2019

The FCC-ee project studies the design of a future 100 km e+/e circular collider for precision studies and rare decay observations in the range of 90 to 350 GeV center of mass energy with luminosities in the order of 1035 cm–2 s–1. In order to reach these luminosity requirements, strong focusing is needed in the interaction regions. Large maximum beta values (of 7736 m for the Z energy) and the small beta star values, make the FCC-ee lattices particularly susceptible to misalignments and field errors. FCC-ee therefore presents an appreciable challenge for emittance tuning. In this paper, we describe a comprehensive correction strategy used for the low emittance tuning. The strategy includes programs that have been developed to optimise the lattice based on Dispersion Free Steering, linear coupling compensation based on Resonant Driving Terms and beta beat correction utilising response matrices. One hundred misalignment and field error random seeds were introduced in MAD-X simulations and the final corrected lattices are presented.
HOM damping options for the Z-Pole operating scenario of FCC-ee
Authors: Gorgi Zadeh S , Flisgen T , Calaga R , van Rienen U
Published: December 2019

The Z-pole option of FCC-ee is an Ampere class machine with a beam current of 1.39 A. Due to high HOM power and strong HOM damping requirements, the present baseline of FCC-ee considers a single-cell cavity at 400 MHz. In this paper, different HOM damping schemes are compared for the Z-pole operating scenario with the aim of lowering the parasitic longitudinal and transverse impedance. The HOM power for each damping scheme is also calculated.
Preliminary Research of HOM for 100MHz Superconducting Cavity in the Pre-research Project of HALS
Authors: Tang Yungai , Wu Cong-Feng , Wang Lin
Published: December 2019

A 100MHz QWR superconducting cavity is researched in the pre-research project of Hefei Advanced Light Source (HALS). Higher order modes (HOM) damping is a big challenge for synchrotron radiation light source. In this paper, we first apply the novel choke mode structure to the 100MHz QWR (quarter wave resonator) cavity in order to damp the HOM. We identify the main harmful higher order modes. The HOMs in the QWR cavity are suppressed by optimizing the choke dimensions. The broadband HOM impedance spectrum of the cavity was also evaluated by calculating the beam induced wake potential in time domain. The results show that choke mode structure has a good HOM damping effect on the QWR cavity.
Research of coherent edge radiation generated by electron beams oscillating free-electron lasers
Authors: Sei N , Ogawa H , Tanaka T , Hayakawa Y , Sakai T , Sumitomo Y , Takahashi Y , Hayakawa K , Nogami K , Zen H , Ohgaki H
Published: December 2019

We have studied far-infrared coherent radiation with S-band linacs at Laboratory for Electron Beam Re-search and Application (LEBRA) at Nihon University and at Kyoto University Free Electron Laser. We have already developed a couple of terahertz-wave sources based on coherent synchrotron radiation and coherent transition radiation, which have been applied to spectroscopic research. Moreover, we developed coherent edge radiation (CER) at the downstream bending magnets in the FEL sections. Because the edge radiation has an annular shape distribution characterized by the asymmetric first-order Laguerre-Gaussian mode, the CER can be extracted from an optical cavity of the FEL system without a diffraction loss of the FEL beam. The root-mean-squared bunch length of the electron beam was evaluated by measuring the CER spectra, which was about the same level as the FEL micropulse width. Although the infrared FELs at LEBRA had a long slippage length, the FEL energy became higher as the bunch length was shorter. The CER intensity can be a guidepost enhancing the FEL power because of the existence of their correlation.
Vacuum lifetime and surface charge limit investigations concerning high intensity spin-polarized photoinjectors
Authors: Friederich S , Aulenbacher K , Matejcek C
Published: December 2019

The Small Thermalized Electron Source at Mainz (STEAM) is a dc photoemission source. It is designed to operate at up to 200 kV bias voltage with an accelerating field of up to 5MV m−1 at the cathode surface. In several experiments, the properties of GaAs operating under the conditions of spin-polarized photoemission were investigated. Its performance, quantum efficiency lifetime and surface charge limit observations for bulk-GaAs will be discussed.
Emittance Reduction of RF Photoinjector Generated Electron Beams by Transverse Laser Beam Shaping
Authors: Gross M , Qian H J , Boonpornprasert P , Chen Y , Good J D , Huck H , Isaev I , Koschitzki C , Krasilnikov M , Lal S , Li X , Lishilin O , Loisch G , Melkumyan D , Mohanty S K , Niemczyk R , Oppelt A , Shaker H , Shu G , Stephan F , Vashchenko G , Will I
Published: December 2019

Laser pulse shaping is one of the key elements to generate low emittance electron beams with RF photoinjectors. Ultimately high performance can be achieved with ellipsoidal laser pulses, but 3-dimensional shaping is challenging. High beam quality can also be reached by simple transverse pulse shaping, which has demonstrated improved beam emittance compared to a transversely uniform laser in the ‘pancake’ photoemission regime. In this contribution we present the truncation of a Gaussian laser at a radius of approximately one sigma in the intermediate (electron bunch length directly after emission about the same as radius) photoemission regime with high acceleration gradients (up to 60 MV/m). This type of electron bunch is used e.g. at the European XFEL and FLASH free electron lasers at DESY, Hamburg site and is being investigated in detail at the Photoinjector Test facility at DESY in Zeuthen (PITZ). Here we present ray-tracing simulations and experimental data of a laser beamline upgrade enabling variable transverse truncation. Initial projected emittance measurements taken with help of this setup are shown, as well as supporting beam dynamics simulations. Additional simulations show the potential for substantial reduction of slice emittance at PITZ.
The use of an RF undulator in the design of an accelerating structure
Authors: Avreline N V , Polozov S M , Ponomarenko A G
Published: December 2019

The idea of accelerating a beam in the accelerating structures based on an RF undulator poses great ad-vantages in high current proton and ions accelerators. The accelerating structure based on an RF undulator uses a combinational wave that consists of the zeroth and the first harmonics for acceleration and focusing. This paper presents the development of this accelerating structure for acceleration of a beam. In particular, we show that this structure is an H-type resonator composed from five cou-pled sections.
Numerical studies on electron beam quality optimization in a laser-driven plasma accelerator with external injection at SINBAD for ATHENAe
Authors: Svystun E N , Assmann R W , Dorda U , Marchetti B , Martinez de la Ossa A
Published: December 2019

Nowadays the electron beams produced in plasma-based accelerators (PBAs) are of sufficient energy for multi-GeV applications. However, to allow PBAs to be usable for demanding applications such as Free-Electron Lasers, the quality and stability of plasma-accelerated beams have to be improved. We present numerical studies on acceleration of an RF-generated electron beam with a charge of 0.8 pC and initial mean energy of 100 MeV to GeV energies by a laser-plasma accelerator. This acceleration scheme is planned to be tested experimentally within the framework of the ATHENAe (Accelerator Technology HElmholtz iNfrAstructure) project at the SINBAD (Short INnovative Bunches and Accelerators at DESY) facility at DESY, Hamburg. Electron beam injection, acceleration and extraction from the plasma are investigated through start-to-end 3D simulations. The effect of the injection phase on the accelerated beam quality is investigated through tolerance studies on the arrival-time jitter between the electron beam and the external laser.
Decay muon beamline design for EMuS
Authors: Song Y P , Bao Y , Tang J Y , Jing H T , Chen Y K , Meng C
Published: December 2019

The beamline design philosophies and simulation results of the decay muon on Experimental Muon Source (EMuS) are reported in this paper. The trunk of the beamline is mainly composed of solenoids to keep a large acceptance, and has been optimized for 45, 150 and 450 MeV/c decay muons respectively according to the π spectra optimization results from the target station. Three spectrometers are planed for decay muons, corresponding to μSR application, muon imaging and muonic application respectively. Decay muons from 45 to 150 MeV/c with polarization above 75% are designed for μSR applications, and high momentum muons up to 450 MeV/c are designed for muon imaging. Negative decay muons from 45 to 150 MeV/c are designed for muonic applications. The momentum of the decay muons is tuneable between 45 and 450 MeV/c.
Remodeling of 150 Mev Ffag Main Ring At Kurns To Pion Production Ring
Authors: Suga K. , Ishi Y. , Uesugi T. , Kuriyama Y. , Fuwa Y. , Okita H. , Mori Y.
Published: December 2019

A possibility of remodeling main ring of 150 MeV FFAG accelerator at Kyoto University, Institute for Integrated Radiation and Nuclear Science (KURNS) to Pion Production Ring (PPR) for muon transmutation study has been discussed. Design was made on the assumption that 400 MeV proton beams circulate and hit a target in the ring to generate pions. Optimizations of lattice parameters and 3D magnet modeling are reported.
First partially stripped ions in the LHC (208Pb81+)
Authors: Schaumann M , Alemany-Fernandez R , Bartosik H , Bohl T , Bruce R , Hemelsoet G H , Hirlaender S , Jowett J M , Kain V , Krasny M W , Molson J , Papotti G , Solfaroli Camillocci M , Timko H , Wenninger J
Published: December 2019

The Gamma Factory initiative proposes to use partially stripped ion (PSI) beams as drivers of a new type of high intensity photon source. As part of the ongoing Physics Beyond Collider studies, initial beam tests with PSI beams have been executed at CERN. On 25 July 2018 lead ions with one remaining electron (208Pb81+) were injected and accelerated in the LHC for the first time. After establishing the injection and circulation of a few208Pb81+bunches, beam lifetimes of about 50 hours could be established at 6.5 TeV proton equivalent energy. This paper describes the setup of the beam tests and observations made.
Reconstruction of the longitudinal phase portrait for the SC CW heavy ion HELIAC at GSI
Authors: Lauber S. , Aulenbacher K. , Barth W. , Burandt C. , Dziuba F. , Forck P. , Gettmann V. , Heilmann M. , Kürzeder T. , List J. , Miski-Oglu M. , Podlech H. , Rubin A. , Schwarz M. , Sieber T. , Yaramyshev S.
Published: December 2019

At the GSI Helmholtzzentrum für Schwerionenforschung (GSI) in Darmstadt, Germany, the HElmholtz LInear Accelerator (HELIAC) is currently under construction. The HELIAC comprises superconducting multigap Crossbar H-mode (SC CH) cavities. The input beam is delivered by an already existing High Charge Injector (HLI). For the further development of the accelerator a detailed knowledge of the input beam parameters to the SC section is necessary. A method for beam reconstruction is incorporated, which provides for longitudinal beam characteristics using measurements with a beam shape monitor and a particle simulation code. This finalizes the investigations on 6D beam parameters, following previous measurements in transversal phase space. The reconstruction of the longitudinal phase portrait is presented.
The First Replacement of the RF Window of the ACS Cavity
Authors: Tamura Jun , Kondo Yasuhiro , Morishita Takatoshi , Naito Fujio , Otani Masashi , Nemoto Yasuo
Published: December 2019

In 2013, the Annular-ring Coupled Structure (ACS) cavities were installed to the Japan Proton Accelerator Research Complex (J-PARC) linac. Since then, the ACS cavities have been stably running. Although any serious problem induced by the RF window had not yet observed, we decided to replace the RF window of one ACS cavity by the newly manufactured one. The major motivations of the replacement are to check the surface condition of the RF window which have been under operation for nearly five years, to confirm that the new RF window fully meets specifications, and to learn how much time is required for high-power conditioning of the new RF window. By making use of the summer maintenance period of 2018, we carried out the replacement. This was the first experience for us to replace the RF window installed to the ACS cavity in the linac accelerator tunnel. As for the removed RF window, there was no any abnormal warning found with the visual examination. At the resuming of the cavity operation after the maintenance period, we conducted the high-power conditioning in a measured manner. It took around fifty hours so that the targeted peak power was stably input to the cavity through the new RF window. The ACS cavity with the new RF window is now stably operating.
Beam manipulations with barrier buckets in the CERN PS
Authors: Vadai M , Alomainy A , Damerau H , Gilardoni S , Giovannozzi M , Huschauer A
Published: December 2019

A barrier bucket scheme is being considered to reduce losses during the Multi-Turn Extraction from the CERN Proton Synchrotron to the Super Proton Synchrotron for the fixed- target physics programme. For effective loss reduction, the extraction kicker has to be triggered during the gap at the time of the longitudinal barrier. Initial beam studies at injection energy and with low intensity beams allowed to fully qualify an existing wide-band cavity to generate one or multiple beam synchronous pulses per turn. Bunch-length stretching and shortening have been exercised with barriers moving in azimuth with respect to the beam. The encouraging results obtained at injection energy guided the implementation of a de-bunching manipulation at higher energy to move all bunches into a single barrier bucket. Beam measurements at a momentum of 14GeV/c, varying intensity and the width of the barrier, demonstrate that a quasi-constant longitudinal line density and an almost fully depleted gap can be achieved at highest intensities. The contribution summarises the results of the beam studies at high energy together with some observations related to the Multi-Turn Extraction.
Hardware Commissioning of the Refurbished ALPI Linac at INFN-LNL to Serve as SPES Exotic Beam Accelerator
Authors: Bisoffi G , Bellan L , Bellato M , Borille D , Bortolato D , Carletto O , Chiurlotto F , Comunian M , Conte A , Contran T , De Lazzari M , Fagotti E , Giacchini M G , Lollo M , Marcato D , Miglioranza M O , Modanese P , Moisio MF , Montis M , Munaron E , Nigrelli G , Pavinato S , Pengo M , Pisent A , Poggi M , Pranovi L , Roncolato C , Rossignoli M , Scarpa D
Published: December 2019

The ALPI linac at INFN-LNL was substantially refurbished in 2018, especially in view of its use as secondary accelerator for exotic species in the framework of the SPES project. In particular: 10 magnetic triplets were replaced with higher gradient ones; two cryomodules with quarter wave resonator were moved from the PIAVE injector to ALPI, so as to make them available both for exotic and stable beams; the cryogenic plant was renovated; the whole linac, its injector and its beam lines were eventually realigned via LASER tracking (LT). The expected outcome of the refurbishment project is a larger beam transmission (crucial for the efficient transport of the unavoidably low current exotic beams) and improved overall reliability so as to further extend the lifetime of an already 25 years old machine. The hardware commissioning of this new configuration will be reported.
Commissioning Results of the Tertiary Beam Lines for the CERN Neutrino Platform Project
Authors: Booth A. , Charitonidis N. , Chatzidaki P. , Karyotakis Y. , Nowak E. , Ortega Ruiz I. , Rosenthal M. , Sala P.
Published: December 2019

For many decades the CERN North Area facility at the Super Proton Synchrotron (SPS) has delivered secondary beams to various fixed target experiments and test beams. In 2018, two new tertiary extensions of the existing beam lines, designated “H2-VLE” and “H4-VLE”, have been constructed and successfully commissioned. These beam lines have been designed to provide charged particles of both polarities in the momentum range from 0.3GeV/c to 12GeV/c. During the design phase, multiple simulation tools and techniques have been employed to optimize the tertiary beam line layout in terms of particle production, transverse beam dynamics and particle identification on an event-by-event basis. In this paper, a comparison of the simulated performance and the first measurement results obtained during the commissioning phase are presented.
SPIRAL2 RFQ bunch lengths and longitudinal emittance measurements
Authors: Normand G. , Di Giacomo M. , Ferdinand R. , Kamalou O. , Lagniel JM. , Savalle A. , Uriot D.
Published: December 2019

The SPIRAL2 beam commissioning has started and the superconducting linac installation is being finalized. The conditioning of the Radio Frequency Quadrupole (RFQ) [1] begun in 2015, and the beam commissioning soon after. Among the beam parameters checked at the RFQ output, the energy, bunch length and longitudinal emittance have been measured for the 3 referenced particles.
Extraction System of Upgraded AVF Cyclotron of RCNP
Authors: Nakao M , Fukuda M , Hara S , Hara T , Hatanaka K , Kamakura K , Kanda H , Koay H W , Morinobu S , Morita Y , Nagayama K , Saito T , Takeda K , Tamura H , Yasuda Y , Yorita T
Published: December 2019

At the Research Center for Nuclear Physics (RCNP) of Osaka University, the demand for both high-intensity and high-quality beam has been increasing. New injection, acceleration, and extraction system of the AVF cyclotron are under development to meet the demand. Extraction system was designed to increase the extraction efficiency since beam loss at electrodes or apertures makes unacceptable radio activation of apparatus when the beam intensity increased. Simulation study confirmed that 10 MeV protons, 65 MeV protons and 140 MeV 4He2+ particles with emittance of 2 mm × 3 mrad can pass through the newly designed extraction system and the existing beam transport line.
Beam Dynamics And Diagnostics For The High Energy Beam Transport Line of Minerva Project At Sck-Cen
Authors: Kraft H. , Perrot L.
Published: December 2019

MYRRHA will be a research infrastructure highlighted by the first prototype of a sub-critical nuclear reactor driven by a 600 MeV particle accelerator (ADS). This project aims at exploring the transmutation of long-lived nuclear wastes. A first phase is planned to validate the reliability of a 100 MeV/4 mA Protons LINAC carrying the beam toward an ISOL facility, prefiguring the real MYRRHA demonstrator at 600 MeV [1]. This project is called MINERVA [2]. This paper presents the status of the beam dynamic studies for the high energy beam transport lines at 100 MeV. In agreement with the project requirements, we describe the specificities of these beam lines for which it is needed to implement a fast kicker-septum. This system will separate the beam between two main lines: toward the beam dump or the ISOL facility [3]. We also describe the studies on the Beam Position Monitor (BPM) selected for MYRRHA. Part of this work was support by the MYRTE project of the European Union [4].
Residual orbits estimation of the injection painting bumps for CSNS
Authors: Huang Ming-Yang , Wang Sheng , Xu Shou-Yan
Published: December 2019

There are three bumps (one chicane bump and two painting bumps) in the injection system of the China Spallation Neutron Source (CSNS). They are the core parts of the injection system and the important guarantee that the Linac beam injecting into the rapid cycling synchrotron (RCS). During the beam commissioning, to check the effect of the residual orbits of the three bumps in the injection region was an important problem. In this paper, the residual orbits of BH and BV painting bumps were studied and estimated in the beam commissioning. The data analysis results showed that the residual orbits of BH and BV painting bumps were very small and they didn't need to be corrected.
Field-Map And Beam Transport Calculations of The Magnetic Separator At Alto Facility At Orsay
Authors: Perrot L , Ollier R
Published: December 2019

The Institute of Nuclear Physics at Orsay (IPNO) has always been a major player in building accelerators for nuclear physics. The Accelerator Linear Tandem Orsay (ALTO) facility is powered by a 50 MeV/10uA linear electron accelerator dedicated to the production of radioactive beams [1]. The production mode is based on the photo-fission process of a thick UCx target heated up to 2000°C and using the Isotopes Separation On-Line (ISOL) technique [2]. For the ionization of the released fission fragments, three ion source types can be coupled to the target: a Febiad ion source, surface ion source, and laser ion source. The facility can deliver the radioactive ions beams (RIB) to six different experimental setups. The mass of the produced mono-charged Radioactive Ions Beam is selected using a magnetic dipole in order to select a nucleus before its transmission through electrostatic devices up to the experimental setups [3]. This paper is focused on the separator that was built and exploited with success since 43 years. The separator is located closely to the exit of the source of RIB production. We propose to revisit this dipole with a precise field-map calculation and particles transport simulations. These results will be used as a first brick for the understanding and reliability of the transmission along the RIB lines at the ALTO facility.
An algorithm for automated lattice design of transfer lines
Authors: Reimann S , Droba M , Meusel O , Podlech H
Published: December 2019

Since the last 20 years, modern heuristic algorithms and machine learning have been increasingly used for several purposes in accelerator technology and physics. Since computing power has become less and less of a limiting factor, these tools have become part of the physicist community’s standard toolkit [1][2] [3] [4] [5]. This paper describes the construction of an algorithm that can be used to generate an optimised lattice design for transfer lines under the consideration of restrictions that usually limit design options in reality. The developed algorithm has been applied to the existing SIS18 to HADES transfer line in GSI.
Minimising the loss of biodiversity and ecosystem services in an intact landscape under risk of rapid agricultural development
Authors: Williams Brooke A , Grantham Hedley S , Watson James E M , Alvarez Silvia J , Simmonds Jeremy S , Rogéliz Carlos A , Da Silva Mayesse , Forero-Medina Germán , Etter Andrés , Nogales Jonathan , Walschburger Tomas , Hyman Glenn , Beyer Hawthorne L
Published: December 2019

As humanity’s demand for resources continues to rise and productive arable lands become increasingly scarce, many of Earth’s remaining intact regions are at heightened risk of destruction from agricultural development. In situations where agricultural expansion is inevitable, it is important to manage intact landscape transformation so that impacts on environmental values are minimised. Here, we present a novel, spatially explicit, land use planning framework that addresses the decision making needed to account for different, competing economic-environment objectives (agricultural production value, biodiversity conservation, ecosystem service retention) when land use change is inevitable within an intact landscape. We apply our framework to the globally significant savannahs of the Orinoquia (Colombia), which in a post-conflict era is under increased agricultural development pressure. We show that while negative environmental impacts can be reduced through planning, the total area of land converted to agriculture is the unavoidable principal driver of biodiversity and ecosystem service loss. We therefore identify planning solutions that perform well across all objectives simultaneously, despite trade-offs among them. When 15%, 20%, 30% and 40% of the study area is allowed to be converted to agriculture, on average planning can improve species persistence and ecosystem service retention by up to 16%, 15%, 12%, and 9%, respectively, when compared to agricultural-focused solutions. Development in the region so far has had an unnecessarily large impact on environmental objectives due to a lack of effective land use planning, creating an ‘opportunity debt’. Our study provides an evidence base to inform proactive planning and the development of environmentally sensible agricultural development policy and practice in the region. This framework can be used by stakeholders to achieve agriculture expansion goals and maximise economic profit while minimising impacts on the environment in the Orinoquia, or any relatively intact region that is being developed.
Recent advances in modeling organic electrochemical transistors
Authors: Colucci Renan , Barbosa Henrique Frulani de Paula , Günther Florian , Cavassin Priscila , Faria Gregório Couto
Published: December 2019

Organic electrochemical transistors (OECTs) have been successfully used as transducers in applications requiring the conversion of ion fluxes to electronic current. These applications range from regular biosensors to sophisticated devices for neuron recording and stimulation. For the rational optimization and understanding of the fundamentals of OECTs and OECT-based applications, however, it is essential to develop in-depth theoretical predictions of experimental data. Here, we review seminal works on modeling both the steady state and transient behavior of OECTs and discuss their strengths and weaknesses. Given that OECTs have been used and applied by a diverse community with very different backgrounds, our intention is to clarify and to extend most of the theoretical developments established so far. Special attention is given to the early models, while trying to make them accessible for everyone in the field of organic bioelectronics.