Round Beam Research Articles

C-phycocyanin shows neuroprotective effect against rotenone-induced Parkinson’s disease in mice

Objective: To investigate the neuroprotective effect of C-phycocyanin in a mouse model of rotenone-induced Parkinson’s disease. Methods: C-phycocyanin (50 mg/kg, i.p., daily) was administered to rotenone (30 mg/kg, p.o., daily) treated mice for 28 days. Behavioral studies (Y-maze, rotarod, round beam walk, and wire-hang tests) were carried out to assess neurobehavioral deficits. Glutathione and malondialdehyde were determined in both serum and striatal tissue. Molecular proteins (AKT, AMPK, NF-κB, BDNF, and alpha-synuclein) in the striatum were estimated using ELISA. Histopathological analyses (hematoxylin and eosin stainning as well as Nissl staining) were carried out to assess structural abnormalities in the striatum. Results: C-phycocyanin significantly increased BDNF levels and decreased alpha-synuclein levels. It also slightly upregulated AMPK and AKT levels without significant difference compared with the rotenone group. Additionally, rotenone-induced elevated oxidative stress and structural abnormalities in the striatum were markedly mitigated by C-phycocyanin. Conclusions: C-phycocyanin might have potential neuroprotective effects against Parkinson’s disease. Further studies are warranted to verify its efficacy and to understand the molecular mechanisms behind the neuroprotective effects of C-phycocyanin in Parkinson’s disease.

Dedicated beam position monitor pair for model-independent lattice characterization at NSLS-II

This paper reports recent lattice characterization results obtained at the National Synchrotron Light Source II (NSLS-II) storage ring, conducted without reliance on a lattice model. A pair of beam position monitors (BPMs) with bunch-by-bunch (B×B) resolution, were recently installed in a section of the storage ring free of magnetic fields. The new BPM pair measured the beam, or bunch’s transverse Poincaré map precisely after the beam was excited. Linear one-turn-matrices (OTM) were then derived, and from these, the 4-dimensional coupled Twiss parameters were extracted at the locations of the BPM pair. By normalizing beam oscillation amplitudes with the Twiss parameters, the global action-variables were obtained. These action-variables facilitated the measurement of the local Twiss parameters observed by other BPMs independent on lattice model. This method is general, and particularly useful in certain scenarios such as a round beam mode in a diffraction-limited light source ring. We applied it to assess both weakly and strongly coupled lattices at the NSLS-II ring. Through analysis of the strongly coupled lattice, the quadrupole tilt errors were estimated to be less than 400 μrad. Utilizing the BPMs’ B×B resolution, for the first time we observed the variations of the linear lattice along a long bunch-train.

Square beams for optimal tiling in transmission electron microscopy

Imaging large fields of view at a high magnification requires tiling. Transmission electron microscopes typically have round beam profiles; therefore, tiling across a large area is either imperfect or results in uneven exposures, a problem for dose-sensitive samples. Here, we introduce a square electron beam that can easily be retrofitted in existing microscopes, and demonstrate its application, showing that it can tile nearly perfectly and deliver cryo-electron microscopy imaging with a resolution comparable to conventional set-ups.

A modified round to flat beam transformation lattice for angular dispersion induced microbunching technique

The angular dispersion induced microbunching (ADM) technique has been proposed to generate high brightness coherent radiation in storage rings by taking advantage of it’s very low vertical emittance. To apply a similar scheme in the linac, it is necessary to reduce the vertical emittance of the electron beam. Generally, angular-momentum-dominated round beams can be generated by immersing the cathode into the axial solenoid magnetic field. The angular momentum can be then removed by skew quadrupoles downstream of the solenoid, resulting in a flat beam with low vertical emittance. In this paper, we propose a possible scheme that holds the possibility to improve the performance of round to flat beam transformation technique by chromatic correction. In this scheme, a chicane is used to introduce the transverse dispersion and sextupoles are employed to correct the chromatic effect. Three-dimensional numerical simulations have been carried out and the results show that a flat beam with transverse emittance ratio of ∼840 can be generated for a bunch charge of 0.5 nC.

Parametric Study of the Effect of Diameter-to-Thickness Ratio Against Bending and Shear Load on the Behavior of Round Hollow Structural Section Beam

The steel-constructed buildings in Indonesia are on the rise, indicating a growing preference for their durability and versatility in construction projects. This led to the general application of Round Hollow Structural Section (Round HSS) as column and beam elements. Therefore, this study aimed to conduct parametric analysis of the effect of Diameter-to-Thickness Ratio (D t-1) on the three-point and four-point flexural analysis of Round HSS beam using MSC Marc/Mentat software. Nonlinear materials and geometries were employed, along with the application of contact analysis, with contacted and contacting bodies. Moreover, the load and boundary condition were set to be similar to the experiment. The results showed that a greater D t-1 led to the possibility of withholding a smaller load and causing smaller displacement in Group A with fixed diameter and different thickness values. Meanwhile, in Group B with fixed thickness but different diameters, a greater D t-1 led to the potential of restraining more load and experiencing smaller displacement. All specimens from both groups were observed to have failed due to a combination of global and local buckling at the right location under the load applied. AISC bending moment calculated was found to be greater than the values obtained from the finite element analysis for all sections under three-point loads. It was also discovered in the four-point flexural analysis that the bending moment of noncompact section was greater than for AISC while those for the compact section were lower. Furthermore, shear strength (Vn) calculated was observed to be greater thanshear force from finite element analysis (Pmax/2).

Applications of vertical damping wigglers in an X-ray diffraction limited storage ring

This study presents a lattice design for an X-ray diffraction limited storage ring (DLSR) light source with a circumference of 864 m and achieving an ultralow natural emittance of 25.6 pm·rad (N-IBS). However, the ultra-low emittance and long damping times lead to significant intra-beam scattering (IBS) effects. To address this issue, the study explores the implementation of vertical damping wigglers (VDWs) to decrease damping times, reduce beam horizontal emittance, and generate vertical emittance to achieve a “round beam” in the 864mDLSR. Through theoretical analysis and accelerator toolbox (AT) simulations, the impacts of VDWs with varied parameters were investigated, and the optimal period length, peak field, and total length were determined. Additionally, the twelve quadrupole magnets in both the front and rear cells of the VDWs were employed to correct linear optics. The findings demonstrate that VDWs could significantly reduce the beam's equilibrium emittance and damping times of the 864mDLSR. Furthermore, a comparison between the spectral brightness and flux of the 864mDLSR with and without VDWs revealed that the 864mDLSR employing VDWs yielded higher brightness and flux.

Concurrent operation of round beam and flat beam in a low-emittance storage ring

In 4th-generation storage rings, whether to operate the beam as round or flat is a critical question. A round beam has equal horizontal and vertical emittances, and is an efficient solution to reduce strong intra-beam scattering effects and lengthen the Touschek lifetimes, but a flat beam produces a brighter photon beam than a round beam. To provide both beams concurrently rather than bifurcating the beam time, this paper presents the exploitation of beam dynamics and the cutting-edge fast pulser that supports concurrent operation of round beam and flat beam.

One-dimensional longitudinal space charge calculation based on integrated green function approach

For fast longitudinal electron beam dynamics study or optimization in an x-ray free electron laser (FEL) linear accelerator, the one-dimensional longitudinal space charge (1D LSC) impedance, assuming a round cylinder beam with uniform transverse distribution is extensively used in both analytical analysis and numerical simulation. In this paper, instead of employing the impedance model in the frequency domain, we directly calculate the longitudinal electric field by convolving the longitudinal beam density with the slice green function, i.e., the longitudinal electric field generated by a slice beam. For high-energy electron beam, the slice green function rapidly diminishes to zero within a distance significantly smaller than the bunch length. In order to resolve the sharp variation, we report on a fast and high-precision method by applying the integrated green function (IGF) approach to compute the 1D LSC field numerically with few grid points, therefore, providing us with an alternative approach to the impedance model.

Compact E-Band Sheet Beam Folded Waveguide Traveling Wave Tube for High Data Rate Communication

The design of a compact <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\textit{E}$</tex-math> </inline-formula> -band (71–76 GHz) sheet beam (SB) folded waveguide (FWG) traveling wave tube (TWT) for high data rate communications is presented in this article. The round beam tunnel for a pencil FWG slow wave structure (SWS) has been redesigned with a rectangular beam tunnel to be suitable for the SB with increased beam current. A novel periodic permanent magnet (PPM)–periodic quadrupolar magnet (PQM) focusing system has been developed to reduce the beam ripple and improve the transmission ratio. A multistep side-out coupler is designed to import and extract the RF power from the SWSs and be compatible with the planar periodic magnetic focusing system. Particle-in-cell (PIC) simulations are employed to evaluate the performance of the high-frequency circuit. Driven by a 1 W signal, the 30-period circuit is estimated to produce more than 100 W power and achieve a 21 dB gain with a less than 0.4 dB variation over 71–76 GHz. Moreover, phase and linearity analysis show a less than 6 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\circ}$</tex-math> </inline-formula> in-band phase distortion and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim$</tex-math> </inline-formula> 30 dB third-order intermodulation distortion (C/3IM) at 30 W of output power, meeting the requirements of a communications-focused TWT. Over 5% circuit efficiency and 40% overall efficiency when equipped with a single-stage collector can be achieved by the compact TWT over the target band.

Improved Spread Spectrum Aloha Protocol and Beam-Hopping Approach for Return Channel in Satellite Internet of Things.

This paper examines potential performances of the Spread Spectrum-based random access technique and proposes an Improved Spread Spectrum Aloha (ISSA) protocol for the return channel in satellite Internet of Things (IoT) based on the beam-hopping technique. The key design driver and detailed solution of ISSA protocol are presented in this work and it is shown that the proposed protocol achieves high throughput and low collision probability. To match user/traffic distribution, delay requirement and channel condition with beam allocation better, a low-complexity heuristic beam scheduling algorithm and a more effective Maximum-Weighted Clique (MWC) algorithm have been proposed. The heuristic algorithm considers the user/traffic distribution, inter-beam interference, and fairness primarily. However, the MWC algorithm gives considerations not only on above factors, but also on delay requirement and channel condition (path loss and rain attenuation) to maximize system capacity. The beam angle and interference avoidance threshold are proposed to measure the inter-beam interference, and the link propagation loss and rain attenuation are considered meanwhile in the channel condition. In the MWC algorithm, we construct an auxiliary graph to find the maximum-weighted clique and derive the weighting approach to be applied in different application scenarios. The performance evaluation of our ISSA protocol compared with the SSA protocol is presented, which achieves a gain of 16.7%. The simulation of the ISSA protocol combined with round robin, heuristic, and MWC beam scheduling for the return link in beam-hopping satellite IoTs is also provided. The results indicate that the throughput in nonuniform user distribution is much lower than in the uniform case without the beam scheduling algorithm. Through the application of the scheduling algorithm, the throughput performance can approach the uniform distribution. Finally, the degree of user satisfaction with different scheduling approaches is presented, which validates the effectiveness of heuristic and MWC algorithms.

Optimization of dynamic aperture by using non-dominated sorting genetic algorithm-II in a diffraction-limited storage ring with solenoids for generating round beam

Optimization of dynamic aperture by using non-dominated sorting genetic algorithm-II in a diffraction-limited storage ring with solenoids for generating round beam

TRANSVERSE SHEAR DEFORMATIONS FOR DEFLECTIONS OF THIN-WALLED BEAMS

The Euler-Bernoulli theory (classical theory) is mainly used when beam deflections are determined. Classical theory takes into account only pure bending while transverse shear deformations are neglected. The paper examines statically determined thin-walled beams (I-beam and thin circular ring): simply supported beams and cantilevers. The load is uniformly distributed along the length of the beam and cantilever and a concentrated force applied at the center of the simply supported beam and at the edge of the cantilever. For the specified cases, as well as for round and rectangular beams, formulas for the correction coefficient were derived. The coefficient takes into account the deformation of the transverse shear. It is shown at what relative length of the thin-wallde beams, the specified deflection exceeds the classical one by more than 5%.

Assessment of the stress state of round and annular cross-section beams made with different tensile and compressive properties materials

At present, there is great interest in carbon-based materials. They have high thermomechanical properties and mass characteristics, are quite technologically advanced. Such materials are widely used in aviation and space technology, for example, for the manufacture of load-bearing elements, beams, frames, as well as aircraft and rocket skin elements. The article considers the stress state of bent beams of circular and annular section made of carbon fiber reinforced plastics. When tested in tension and compression, such materials, called multi-modulus, exhibit different properties. Therefore, for strength calculations, it is necessary to use special strength models. A method is proposed for calculating the bending of beams of circular and annular cross-section made of M46 and IMS-65 carbon fiber reinforced plastics. Their tensile and compressive moduli and corresponding strengths were determined by testing on a ZDM-10 machine with an accuracy of ±1,25%. The examples show that in the calculations it is necessary to take into account the difference in tensile and compression properties, as well as the real position of the neutral axis of the bent beam section.

Behavioral and molecular effects of Ubtf knockout and knockdown in mice

The UBTF E210K neuroregression syndrome is caused by de novo dominant mutations in UBTF (NM_014233.3:c.628G > A, p.Glu210Lys). In humans, onset is typically at 2.5 to 3 years and characterized by slow progression of global motor, cognitive and behavioral dysfunction. Other potentially pathogenic UBTF variants have been reported in humans with severe neurological disease and it remains undetermined if the UBTF E210K mutation operates via gain- and/or loss-of-function. Here we examine the behavioral, cognitive, motor, and molecular effects of Ubtf knockout and knockdown in mice as a means of gauging the role of loss-of-function in humans. Ubtf+/− mice show progression of behavioral (dominance tube), cognitive (cross maze), and mild motor abnormalities from 3 to 18 months. At 18 months, Ubtf+/− mice had more slips on a raised 9-mm round beam task, shorter latencies to fall on the accelerated rotarod, reduced open field vertical and jump counts, and significant deficits in spatial learning and memory. Via crosses to Nestin-Cre (NesCre) mice we found that homozygous Ubtf deletion limited to the central nervous system was embryonic lethal. Tamoxifen-induced homozygous knockdown of Ubtf in adult mice with the Cre-ERT2 system was associated with precipitous deterioration in neurological functioning. At the molecular level, 18-month-old Ubtf+/− mice showed mild increases in cerebellar 53BP1 immunoreactivity. These findings show that UBTF is essential for embryogenesis and survival in adults, and the deleterious effects of UBTF haploinsufficiency progress with age. Loss-of-function mechanisms may contribute, in part, to the human UBTF E210K neuroregression syndrome.

Designing linear lattices for round beam in electron storage rings using the solution by linear matrices analysis

For some synchrotron light source beamline applications, a round beam is preferable to a flat one. A conventional method of obtaining round beam in an electron storage ring is to shift its tune close to a linear difference resonance. The linearly coupled beam dynamics is analyzed with perturbation theories, which have certain limitations. In this paper, we adopt the Solution by LInear Matrices (SLIM) analysis to calculate exact beam sizes to design round beam lattices. The SLIM analysis can deal with a generally linearly coupled accelerator lattice. The effects of various coupling sources on beam emittances and sizes can be studied within a self-consistent frame. Both the on- and off-resonance schemes to obtain round beams are explained with examples. The SLIM formalism for two widely used magnet models: combined-function bending magnets, and planar wigglers and undulators, is also derived.

High-quality micro-shape fabrication of monocrystalline diamond by nanosecond pulsed laser and acid cleaning

The flat plane of small surface roughness below 0.1 µm average roughness was obtained for monocrystalline diamond by nanosecond pulsed laser irradiation of 1060 nm and post-process acid cleaning, at a laser fluence around the material removal threshold value. The glossy and flat plane at the bottom of the micro-groove was parallel to the top surface of the specimen, although the round beam of Gaussian mode was irradiated in the direction perpendicular to the top surface of specimen. The square beam of top-hat mode produced a shallower micro-groove with a wider, flatter bottom compared with the round beam in Gaussian mode. The creation method of the flat plane with small surface roughness was discussed in the arrangement strategy of linear micro-grooving by the square beam of top-hat mode. Normal side-by-side repetition of linear micro-grooving did not create a flat plane with constant depth. Therefore, a two-step scanning method was proposed in order to overcome the problem in the normal side-by-side repetition of liner micro-grooving. Non-removal areas were partly retained between the processing lines in the first step, and the laser scanning was conducted on the retained area in the second step. The newly proposed two-step scanning method was practical and useful to create a widely flat plane with small surface roughness, and the two-step scanning method provided superior control over the micro-groove depth. This proposed method can reduce the surface roughness in addition to the shape creation of monocrystalline diamond, and it can be used as a high-quality micro-shape fabrication method of monocrystalline diamond.

Experimental study on the flexural behaviour of timber beams strengthened with high ductility and low cost hybrid fibre sheets

Timbers with defects are often used in historical buildings. However, the existing fibre sheet reinforcing technology for the timber beams is difficult to balance the strength, ductility and cost. This paper aims to develop novel high ductility hybrid fibre sheets for strengthening timber beams at a lower cost than available methods. First, four types of unidirectional and two types of bidirectional fibre reinforced polymer (FRP) sheets were designed and evaluated using scanning electron microscopy (SEM) and tensile tests. Then, the FRP sheets were used to make 68 timber beams with square and round cross sections for bending tests. Finally, parameter analysis was conducted to evaluate the enhancement law of specimens with different sheet layers, fibre types, reinforcement angles and interlaminar hybrid modes. The results show that the reinforcement angle of a round timber beam has a great influence on its ultimate bearing capacity, for which the recommended value range is 45°∼60°. Unidirectional fibre sheets with a fibre ratio of carbon fibre:aramid fibre:glass fibre = 2:1:1 have a positive hybrid effect on bearing capacity and can improve the ultimate deflection of timber beams by 69.2–115.4% with one layer. These research results can contribute to state-of-the-art knowledge about round and square section timber beams strengthened with hybrid fibre sheets and the conservation of timber structures.

The energy of ions bombarding the vacuum chamber walls. Elliptic beams

In high intensity positively charged beam machined the beam intensity could be limited by the ion induced pressure instability. This is a phenomenon occurs when residual gas molecules can be ionised and accelerated towards beam chamber walls causing ion stimulated gas desorption and residual gas density increase. Under certain conditions residual gas density can increase to such values when the beam loss rate becomes unacceptable. To mitigate this phenomenon, a vacuum system should be properly designed to provide sufficient pumping at correct locations, this includes an accurate gas dynamics modelling of beam vacuum chamber. This model requires a number of input parameters, among whose the energy of the ions bombarding vacuum chamber walls is the most critical one. In the previous paper the energy of ions bombarding the vacuum chamber walls was studied for round beams. This paper is reporting on how the elliptic shape of beams affects these results.

Round Colliding Beams: Successful Operation Experience

Round Colliding Beams: Successful Operation Experience

Element-Free Galerkin Method Modeling of Thermo-Elastic-Plastic Behavior for Continuous Casting Round Billet

When solving the coupled thermal-mechanical problem of the metal solidification, the mesh-based numerical methods suffer from the inconsistency of mesh lines and curved boundaries. Furthermore, the mesh should be continually reconstructed to comply with the interface when dealing with the moving boundary such as phase transition, which brings great difficulties to the numerical calculation. Based on the plane stress assumption, the present work establishes a two-dimensional thermo-elastic-plastic calculation model for continuous casting round billets using the Element-Free Galerkin method, and the correction scheme of elastoplastic transition region has been explored. The results show that the correction scheme has a slight effect on magnitude of the equivalent stress and no impact on the subsequent plastic deformation zone. The elastoplastic transition region of shell surface appears in the range of 100 to 200 mm below the meniscus, and the averaged plastic stress is about 2.27 times of the elastic stress at the mold outlet. Near the interface region of liquid–solid phase exhibits an elastic deformation behavior, while far from the interface region appears plastic deformation in which the elastic stress remains invariable. The Element-Free Galerkin method is discretized by a series of arbitrary nodes, which exhibits high accuracy and great flexibility in dealing with moving interface problems. It provides a powerful approach to calculate and analyze the heat transfer/mechanical behavior with complex geometric boundaries such as round billet, chamfered billet, and beam blank.