Secondary Beam Research Articles

Nanoscopic subcellular imaging enabled by ion beam tomography

Multiplexed ion beam imaging (MIBI) has been previously used to profile multiple parameters in two dimensions in single cells within tissue slices. Here, a mathematical and technical framework for three-dimensional (3D) subcellular MIBI is presented. Ion-beam tomography (IBT) compiles ion beam images that are acquired iteratively across successive, multiple scans, and later assembled into a 3D format without loss of depth resolution. Algorithmic deconvolution, tailored for ion beams, is then applied to the transformed ion image series, yielding 4-fold enhanced ion beam data cubes. To further generate 3D sub-ion-beam-width precision visuals, isolated ion molecules are localized in the raw ion beam images, creating an approach coined as SILM, secondary ion beam localization microscopy, providing sub-25 nm accuracy in original ion images. Using deep learning, a parameter-free reconstruction method for ion beam tomograms with high accuracy is developed for low-density targets. In cultured cancer cells and tissues, IBT enables accessible visualization of 3D volumetric distributions of genomic regions, RNA transcripts, and protein factors with 5 nm axial resolution using isotope-enrichments and label-free elemental analyses. Multiparameter imaging of subcellular features at near macromolecular resolution is implemented by the IBT tools as a general biocomputation pipeline for imaging mass spectrometry.

Research on Mechanical Performance of the Connection of Fabricated Primary and Secondary Steel Beam

Due to many advantages, prefabricated buildings are the trend of future development. In order to study the mechanical properties of the steel structure beam-beam connection node, referring to related materials, this paper designs a bolted connection node between main and secondary steel beams. By changing the key parameters such as the thickness of the supporting plate and the diameter of the bolt, the finite element software ABAQUS is used to simulate the primary and secondary beam nodes. Based on the finite element results, the force mechanism, failure mode, flexural bearing capacity and rotational stiffness of the nodes are analyzed, and some parameter design suggestions are proposed: the thickness of the supporting plate should not be less than 8mm, and the bolt diameter should not be less than 20mm.

New Crystal Devices for Use at the U-70 Accelerator

In view of the successful experience in the generation of pion and kaon secondary beams using a focusing crystal, it has been proposed to build at the U-70 accelerator a new-type channel of secondary particles that does not consume electric power. It has been shown experimentally that an extraction septum magnet can be protected from radiation by applying a multistrip crystal device through current septum shadowing by the crystal that involves the bulk reflection regime for the deflection of particles. The listed applications of crystals are novel in the world practice with accelerators.

A human heartbeat frequencies based 2-DOF piezoelectric energy harvester for pacemaker application

Abstract In the last decade, piezoelectric energy harvesters have received a significant attention from the scientific community. This comes along with the need of developing self-powered devices such as medical implant to reduce the cost and risk of surgery. This paper investigates a two degree of freedom (2-DOF) piezoelectric energy harvester device to be integrated into a pacemaker. The 2-DOF is designed as a cut-out beam with a secondary beam cut into a primary one. The system is developed to operate in the frequency range of 0–2 Hz, with an acceleration of 1 g (9.8 m/s2) to match the heartbeat frequencies (1–1.67 Hz). The system uses a Lead Zirconate Titanate (PZT) and a Poly Methyl Methacrylate (PMMA) as lead beam to compensate the brittleness of PZT. COMSOL Multiphysics software is used to model and analyze the resonant frequencies of the system, and the stress in the piezoelectric beam. The proposed device has a compact volume of 26 × 11.58 × 0.41 mm, which can fit perfectly in a pacemaker whose battery volume has been reduced by 50%. The output voltage and power are determined through analytical calculus using Matlab. Typical pacemakers require 1 μW to operate. Thus, with a peak power of 30.97 μW at 1.5 Hz and an average output power of 11.05 μW observed from 0.9 to 1.7 Hz, the harvester can power a pacemaker. It is assumed that the energy harvester could extend its life time for 5–10 more years. Furthermore, the harvester operates at extremely low frequency and produces reasonable power, making it suitable for biomedical devices.

Local Multimodal Electro‐Chemical‐Structural Characterization of Solid‐Electrolyte Grain Boundaries

AbstractTypical models of polycrystalline ionic materials treat the grain boundary properties as single valued, without consideration of the full range of values that define the macroscopically measured average. Here a unique experimental platform suitable for local multimodal characterization of individual grain boundaries in bicrystal fibers is reported. A variation of three orders of magnitude in the grain boundary conductivity of ceria is observed, as measured across six individual bicrystals by both alternating current impedance spectroscopy and direct current (D.C.) linear sweep voltammetry. Nonlinear behavior of the D.C. measurements is consistent with resistance due to a space charge effect. Time‐of‐flight secondary ion beam spectroscopy reveals a correlation between grain boundary resistance and the concentration of impurities Si, Al, and Ca segregated at the grain boundaries, although the bulk concentrations of these impurities are negligible. Electron backscatter diffraction analysis of the crystal orientations suggests a correlation between the misorientation across the grain boundaries and grain boundary resistance. These correlations point towards a grain boundary resistance that arises from impurity‐generated space charge effects and variations in impurity concentration and hence resistivity driven by the energetics of impurity segregation to grain boundaries of differing surface energies.

COMPARATIVE STRUCTURAL STUDY OF INNOVATIVE STRENGTHENING PROPOSALS OF TIMBER BEAMS IN HISTORICAL BUILDINGS IN CAIRO USING TWO-LAYERED COMPOSITE SYSTEM

Traditional restoration and rehabilitation work of flat timber ceilings at historical Islamic buildings in Cairo generally require the dismantling of most of their timber parts (i.e. timber planks, secondary beams, etc.) to expose the timber main beams and conduct the work. Hence, these parts are liable to damage and lose during the dismantling that requires time, money and effort to achieve. Hence, the author conducted this study to overcome the dismantling work and propose effective strengthening techniques for the timber beams utilizing two-layered composite system. This paper reported the limited application of the layered system in the construction of the historical timber beams in Cairo. It studied a number of innovative strengthening proposals of the timber beams from their upper-side merely while leaving the exposed bottom surface intact, apart from its indispensable shoring. Hence, a small experimental and a wide comparative analytical investigation of the strengthening proposals utilizing two-layered composite system are conducted. Several 2D Finite Element numerical models using well-known software were conducted. The modelling techniques of various interfacial conditions of the two-layered beams are established and evaluation of the strengthening proposals is conducted. Finally, conclusions and recommendations are derived.

Behaviour of Flat Slab, Waffle Slab, Ribbed & Secondary Beam in a multistorey Building under Seismic Response: A Review

Behaviour of Flat Slab, Waffle Slab, Ribbed & Secondary Beam in a multistorey Building under Seismic Response: A Review

Influence of the Secondary Ion Beam Source on the Laser Damage Mechanism and Stress Evolution of IBS Hafnia Layers

Ion beam sputtered hafnia is a preferred high index coating material for laser applications. It exhibits a mostly amorphous structure and an adequate laser-induced damage (LIDT) threshold. In this work, we investigated the influence of an assisting ion source on the film stress as well as the LIDT of the sputtered hafnia layers. The stress increases with an increasing ion energy of the assisting ion beam. We identified a maximum compressive stress of 3–3.5 GPa before the film cracks, blisters, and delaminates. Different states of stress lead to different laser-induced damage thresholds and damage morphologies.

Neutron pick-up reactions in 18O (10 MeV/nucleon) + Ta

The availability of new radioactive ion beams has broadened the study of nuclear reactions and nuclear structure. The main mechanism to produce the secondary beams is the fragmentation of the projectile. An alternative method for the production of the exotic nuclei is the multinucleon transfer. We measured production cross section for the B, C, N and O isotopes in the reaction 18O + Ta and the beam energy at 10 MeV/nucleon. The cross-sections were obtained by integrating the momentum distributions of the isotopes. It was shown that in deep inelastic processes the production yields of different isotopes could be well described using statistical models and could also be explained by the Qgg-systematic.

Bound-free pair production from nuclear collisions and the steady-state quench limit of the main dipole magnets of the CERN Large Hadron Collider

During its Run 2 (2015-2018), the Large Hadron Collider (LHC) operated at almost twice higher energy, and provided Pb-Pb collisions with an order of magnitude higher luminosity, than in the previous Run 1. In consequence, the power of the secondary beams emitted from the interaction points by the bound-free pair production (BFPP) process increased by a factor ~20, while the propensity of the bending magnets to quench increased with the higher magnetic field. This beam power is about 35 times greater than that contained in the luminosity debris from hadronic interactions and is focused on specific locations that fall naturally inside superconducting magnets. The risk of quenching these magnets has long been recognized as severe and there are operational limitations due to the dynamic heat load that must be evacuated by the cryogenic system. High-luminosity operation was nevertheless possible thanks to orbit bumps that were introduced in the dispersion suppressors around the ATLAS and CMS experiments to prevent quenches by displacing and spreading out these beam losses. Further, in 2015, the BFPP beams were manipulated to induce a controlled quench, thus providing the first direct measurement of the steady-state quench level of an LHC dipole magnet. The same experiment demonstrated the need for new collimators that are being installed around the ALICE experiment to intercept the secondary beams in the future. This paper discusses the experience with BFPP at luminosities very close to the future High Luminosity LHC (HL-LHC) target, gives results on the risk reduction by orbit bumps and presents a detailed analysis of the controlled quench experiment.

Influence of the seismic shear proportioning factor on steel MRFs seismic performances

The work herein present has the purpose of investigating the influence of the shear proportioning factor for the design of Moment Resisting Frames where the most severe condition for the design of dissipative zones is the seismic action. This situation often happens when the frames are arranged parallel to the warping of secondary beams, i.e. when vertical loads are not relevant for the dimensioning of the beam sections. The shear proportioning factor is used to distribute the base shear among all the storeys of steel moment-resisting frames to design the beam sections according to the required storey seismic action. To this scope, reference is made to several MR-Frame structures designed by Theory of Plastic Mechanism Control design approach and Eurocode 8 where shear proportioning factors variable along with the structure height and equal to 1 are assumed. A shear proportioning factor variable has the scope of promoting the simultaneous activation of dissipative zones in plastic range while the constant one should time-spread the yielding of dissipative zones. The seismic performances of these frames are investigated using both push-over and dynamic non-linear analyses.

Numerical Analysis of Steel-Concrete Composite Beam with Blind Bolt under Simultaneous Flexural and Torsional Loading

This paper investigates the composite beam with bolt shear connectors. Composite beams are usually used as secondary beam in buildings. It is clear that studying the torsion in side beams in buildings such as balconies is of great importance. The composite beam was loaded under three different loading conditions including a pure flexural loading, and simultaneous flexural loading with two alternative torsional loading modes. The obtained results from the analysis were compared with each other by three-dimensional non-linear finite element model using ABAQUS. The obtained results, including the mid span deflection, the rotation and slip of composite beams under different loading conditions were investigated. The effect of the type and number of shear connectors on slip of composite beam was studied, too. The results indicated that the slip between the steel beam and the concrete slab along the composite beam increased due to flexure loading, but the torsional loading had a slight effect on the slip.

Performance of the OEDO beamline

The OEDO (Optimized Energy Degrading Optics for RI beam) beamline has been developed to obtain low-energy (10 – 50 MeV/u) RI beams by slowing down the secondary beams at RIBF, RIKEN. Such beams are useful probes to investigate nuclear structure by means of nucleon transfer and Coulomb excitation reactions. The beamline is designed to produce a well-focused beam of small energy spread with the help of the angle-tuneable wedge degrader and the radio-frequency deflector. The commissioning and first physics experiments using the OEDO beamline were carried out in 2017. OEDO successfully provided the energy-degraded beams of Se, Zr, and Pd. Its performance including the optics and transmission was evaluated using those experimental data and it functions properly as designed. We expect that our novel beamline shed a light on the experimental approaches involving nuclear reactions at several tens of MeV/u to expand our knowledge of nuclei far beyond the line of stability.

Test Beams of the LPI Accelerating Complex Pakhra

In this paper, we report the characteristics of the generated beams, the extracted electron beam and the beam of secondary electrons/positrons, of the LPI accelerator complex Pakhra as of November 2019 for testing and calibrating detectors used in large accelerator and astrophysical experiments. At energies of 250–500 MeV of the electron beam ejected into Hall 1 from the S-25R synchrotron, its energy resolution is δ ~ 1% and the intensity can be changed by collimators in the range of 103–1010 s–1. The quasi-monochromatic beam of secondary electrons produced in Hall 2 typically has an energy in the range of 50–300 MeV, a corresponding energy resolution of δ = 14–2%, and an intensity of ~ 102 s–1. The performed simulation of the characteristics of the secondary positron beam allowed selecting the optimal geometry of the setup and showed good agreement with the experimental data obtained later.

Application of time and motion study to increase the productivity and efficiency

The productivity and efficiency in any construction is always a challenge. Due to various factors the efficiency of men and machine gets reduced hampering the productivity. The purpose of this study is to highlight the benefits of time and motion study employed in construction sector. Time and motion study and work sampling has been employed to measure the productivity of the various construction activities and the paper discusses its application to the various phases of erection of steel structure such as installation of purlins, installation of primary beams and installation of secondary beams on the arrival slab of an airport. The parameters such as efficiency, productivity, tool time, support time and idle times are observed. Motion corrections and time corrections are applied. It is expected that employing lean concepts to construction will help in increasing productivity and reduce risks. After first week of observation and then employing time and motion study corrections, an increase of 37.95% is observed in terms of efficiency, an increase of 218.03% is observed in terms of productivity and an increase of 93.25% is observed in terms of tool time. The idle time showed a decrease of 40.24%.The results are highly promising and hence the management of construction industry need to consider the application of time and motion study not only from the point of view of enhancing efficiency and resource usage, but should also discuss the soft side of employee psychology.

Paneled Composite Beams (Dept.C)

Recently, composite members had been widely used in construction, where the use of appropriate materials arranged in an optimum geometric configuration providing the required compressive and tensile strength, achieve greater stiffness, material saving, less own weight and better vibration resistance. Unfortunately, the behavior of continuous composite beams supported on other beams is unpredictable and such system requires a more complicated design. Most of the current design codes do not mention the behavior of this system due to the lack of both experimental data and practical experience. Therefore the designer usually ignores the real behavior of such system which acts as a paneled beam system, and considers the secondary beams as simply supported composite beams, or as continuous steel beams leading to either unsafe results or over conservative results, due to the lack of adequate code guidance, Thus, this paper explains the behavior of such system using linear finite element analysis, together with the most important factors affecting it.

A new analytical formulation for the stiffness and resistance of the additional plate in bending in beam-to-beam steel joints

This paper focuses on the stiffness and resistance of the additional plate in bending. This is a component which appears in beam-to-beam bolted steel joints, when a secondary beam with a flush end plate is attached orthogonally to the primary beam by an additional plate welded between its flanges. In this work, six experimental tests have been carried out to calibrate a finite element model which has been used to develop a wide parametric study. Thus, a new formulation for stiffness and resistance based on an equivalent frame is proposed.

Energy spread estimation of radioactive oxygen ion beams using optical imaging

Radioactive ion (RI) beams combined with in-beam positron emission tomography enable accurate in situ beam range verification in heavy ion therapy. However, the energy spread of the radioactive beams generated as secondary beams is wider than that of conventional stable heavy ion beams which causes Bragg peak region and distal falloff region broadening. Therefore, the energy spread of the RI beams should be measured carefully for their quality control. Here, we proposed an optical imaging technique for the energy spread estimation of radioactive oxygen ion beams. A polymethyl methacrylate phantom (10.0 × 10.0 × 9.9 cm3) was irradiated with an 15O beam (mean energy = 247.7 MeV u−1, standard deviation = 6.8 MeV u−1) in the Heavy Ion Medical Accelerator in Chiba. Three different momentum acceptances of 1%, 2% and 4% were used to get energy spreads of 1.9 MeV u−1, 3.4 MeV u−1 and 5.5 MeV u−1, respectively. The in-beam luminescence light and offline beam Cerenkov light images were acquired with an optical system consisting of a lens and a cooled charge-coupled device camera. To estimate the energy spread of the 15O ion beams, we proposed three optical parameters: (1) distal-50% falloff length of the prompt luminescence signals; (2) full-width at half maximum of the Cerenkov light signals in the beam direction; and (3) positional difference between the peaks of the Cerenkov light and the luminescence signals. These parameters estimated the energy spread with the respective mean squared errors of 2.52 × 10−3 MeV u−1, 5.91 × 10−3 MeV u−1, and 0.182 MeV u−1. The distal-50% falloff length of the luminescence signals provided the lowest mean squared error among the optical parameters. From the findings, we concluded optical imaging using luminescence and Cerenkov light signals offers an accurate energy spread estimation of 15O ion beams. In the future, the proposed optical parameters will be used for energy spread estimation of other RI beams as well as stable ion beams.

Structural investigation of the collapse of the 16‐story Plasco building due to fire

SummaryOn January 19, 2017, the 16‐story Plasco tower located in Tehran, the capital city of Iran, collapsed in several stages, due to a fire lasting 3.5 h. This paper presents the results of numerical investigations on how the structure behaved during that incident. In this regard, initially, a part of floor system including main truss girders, secondary truss beams, tie beams, and reinforced concrete slab is simulated to study its deformed shape and collapse modes. Then 2D and 3D models of the building are developed to evaluate the global behavior of the structure under fire. The results show that at elevated temperatures, deflection of the floor system, main trusses, and out‐of‐plane bending of the beam‐to‐column gusset plates become excessive, leading to partial collapse of floor, in the location of fire initiation. Also, 2D models show that thermal expansion and catenary action of heated truss induce large lateral displacement and bending moment in perimeter column that cause failure of this column at about 650°C. Finally, 3D models indicate that general collapse of the building is initiated by buckling of the external columns located in the southern perimeter of the building. This result is in good agreement with videos and photos showing actual collapse of the structure.

Single-nucleon knockout cross sections for reactions producing resonance states at or beyond the drip line

Single-nucleon knockout cross sections from fast secondary beams of the proton-drip-line nuclei $^{9}\mathrm{C}$, $^{13}\mathrm{O}$, and $^{17}\mathrm{Ne}$ on a $^{9}\mathrm{Be}$ target have been studied with emphasis on the production of resonance states. These states were identified by their invariant mass, and resonances with two-, three-, and five-body exit channels were examined. The measured cross sections for these states were compared with eikonal-model predictions using shell-model or variational Monte Carlo spectroscopic factors. The experimental yields were found to be suppressed relative to the model predictions, especially when a well-bound neutron or proton is removed. This suppression exceeds that found systematically in measured inclusive cross sections to particle-bound final states. In neutron knockout from $^{9}\mathrm{C}$ and $^{13}\mathrm{O}$ projectiles, this suppression of the unbound ground-state residuals yield is a factor of two to three times larger than that found in the bound final-state studies. Modifications to the structure of these systems due to coupling of the shell-model configurations to the continuum is expected to contribute to this extra suppression, especially when the final state is a near-threshold resonance. However, other considerations including the role of nuclear dynamics may be required to explain all the observed trends.