Orthogonal Strip Research Articles

Evaluation of various FRP strengthening configurations for RC beam-column joints

There are several methods for strengthening reinforced concrete joints. Due to the unique properties of FRP (Fiber Reinforced Polymer) composites, the use of FRP laminates is one of the most commonly used techniques. The high cost of preparing concrete surfaces and attaching FRP laminates is a restricting factor for its application in reinforced concrete joint retrofit. Therefore, determining proper configurations that reduce the needed FRP material, as well as the surface preparation required for attaching FRP is an important factor in decreasing the strengthening cost. The proper arrangements of FRP strips can improve their performance in the rehabilitation and retrofit of reinforced concrete joints. To determine the proper configuration of FRP strips, finite element modeling was employed. The connection specimens are modeled in ABAQUS general-purpose finite element software and are classified into 10 general groups. To improve the performance of FRP strip configuration, the determined arrangement is investigated for different thicknesses and different widths of the FRP strips, and their results are compared with those of the connection specimen strengthened with full FRP coverage. The analysis results indicated that the load-bearing capacity of the connection retrofitted by the combined configuration of X-shape and orthogonal strips of FRP is close to that of the specimen with full FRP coverage. In this suitable configuration, the required FRP strips are reduced by about 30%, which decreases the cost and construction works needed for concrete joint rehabilitation.

A Compact Circularly Polarized Crossed Dipole Antenna with Wide Bandwidth using Split Ring Resonator and Parasitic Patches

A new compact broadband circularly polarized (CP) crossed dipole antenna using split ring resonator (SRR) and parasitic patches are presented. The proposed antenna is mainly composed of two orthogonal strip dipoles, two 90∘ phase delay lines, four SRRs, and four parasitic patches. The combination of the orthogonal strip dipoles and the delay lines forms a crossed dipole as the main CP radiator. The well-designed SRR can extend the current path and improve the current distribution of high-frequency without increasing the size of the antenna, thereby reducing the size of the antenna and increasing the axial ratio (AR) bandwidth of the high-frequency. The introduction of parasitic patches can improve the current distribution between the upper and lower cut-off frequency points of the bandwidth, and make up for the defects of the insufficient bandwidth of the crossed dipole and the SRR, thereby realizing broadband CP radiation. To verify the antenna, a physical prototype is fabricated. The measured results show that the impedance bandwidth (IBW) of 69.1% (1.38-2.84 GHz), and a wide AR bandwidth of 57.7% (1.43-2.59 GHz). In addition, the designed antenna achieves a stable gain in the working band and a certain band-edge selectivity. Such a single-fed, simple structure and the wideband CP antenna is an excellent candidate for communication systems such as ISM (2.4 GHz), WiBro (2.3-2.39 GHz)and Inmarsat.

A wideband flexible electro-textiles material linear-to-circular polarizing metasurface for S-band CubeSat

In this paper, a flexible linear-to-circular polarizer FSS-based surface made from a single layer of cloth is introduced. Two orthogonal strips serve as the foundation for the proposed structure's architecture, with a central aperture in the unit cell for the pico-satellites aimed towards the S-Band. A wearable material called Shieldit Super serves as the conducting fabric in the unit cell, while Felt serves as the substrate. For the working center frequency of 2.41 GHz, the unit cell size is 0.32λ × 0.26λ × 0.02λ. It has a 3 dB axial ratio bandwidth (ARBW) of 42.90% and an axial ratio of 0.08 dB at 2.41 GHz, which is very close to zero. In addition, the FSS metasurface provides a bandwidth of up to 56.84% with 90% conversion efficiency. The polarizing surface is then created by multiplying this unit cell by a 6 × 6 array. The proposed structure's performance is proven by placing it in front of a patch antenna operating at 2.41 GHz. In addition to efficiently converting linearly polarized waves into circularly polarized waves, the antenna's performance improved when paired with the polarizing surface, as measured by the realized gain, which went from 3.14 dBi to 7.33 dBi.

Dual-Band Circularly Polarized Annular Ring Patch Antenna for GPS-Aided GEO-Augmented Navigation Receivers

A compact, single- feed, dual band, circularly polarized annular ring patch antenna coupled to a cross slot is proposed in this letter for GPS-aided GEO-augmented navigation (GAGAN) receivers covering L band, centered at 1176.45 MHz (L5) and 1575.42 MHz (L1) frequencies. The antenna consists of two annular rings configured by two small strips, which is coupled to a cross slot in the ground plane for gain enhancement. Circular polarization in both the bands is produced by introducing perturbations in outer annular ring and two orthogonal strips in the center space of inner annular ring. The proposed CP antenna radiates LHCP in both the desired frequencies. Two shorting pins are introduced near the feed to improve impedance matching. The simulated and measured reflection coefficient, gain, circular polarization, and axial ratio are in accord with each other. The measured 10 dB bandwidth is 2.7% (1168–1200 MHz) for the L5 and 2.5% (1560–1600 MHz) for L1. The AR bandwidth below 3 dB for the designed antenna is 1.5% (1156–1174 MHz) for L5 and 1% (1556–1572 MHz) for L1.

60 GHz dual‐polarized magneto‐electric dipole antenna array with hybrid gap waveguide feeding network in low temperature co‐fired ceramic technology

AbstractA 60 GHz 8 × 8 dual‐polarized aperture‐coupled magneto‐electric (ME) dipole antenna array in low temperature co‐fired ceramic (LTCC) technology is proposed. Taking advantage of the LTCC technology of high integration, the antenna array is composed of three parts, including the wideband ME dipole elements, dual‐polarized strip‐line series feeding network and low‐loss gap waveguide (GWG) feeding network. The ME dipole antenna element is fed by aperture coupling with 45° rotation. Two separate orthogonal strip lines are located right below the aperture to realize dual polarization performance. The simulated −10 dB impedance bandwidth of the dual‐polarized antenna element is 50–66.5 GHz with an isolation lower than −20 dB for two input ports. By employing the proposed radiating element, a 4 × 4 wide‐band dual‐polarized antenna subarray is realized by using strip‐line series‐feed technology. A compact hybrid low‐loss feeding network is realized by combing the GWG technology with the strip‐line series feed technology. For demonstration, one prototype was fabricated. The measured impedance bandwidth is 14.2% and 16.7% respectively for dual polarizations with |S11| < −8 dB, and the port isolation is lower than −20 dB over the entire frequency band of interest.

Pulse shape discrimination for GRIT: Beam test of a new integrated charge and current preamplifier coupled with high granularity Silicon detectors

The GRIT (Granularity, Resolution, Identification, Transparency) Silicon array is intended to measure direct reactions. Its design is based on several layers (three layers in the forward direction, two backward) of custom-made trapezoidal and square detectors. The first stage is 500 μm thick and features 128 × 128 orthogonal strips. Pulse shape analysis for particle identification is implemented for this first layer. Given the compacity of this array and the large number of channels involved (>7500), an integrated preamplifier, iPACI, that gives charge and current information has been developed in the AMS 0.35 μm BiCMOS technology. The design specifications and results of the test bench are presented. Considering an energy range of 50 MeV and an energy resolution (FWHM) of 12 keV (FWHM) for the preamplifier, the energy resolution for one strip obtained from alpha source measurement in real conditions is 35 keV. The current output bandwidth is measured at 130 MHz for small signals and the power consumption reaches 40 mW per detector channel. A first beam test was performed coupling a nTD trapezoidal double-sided stripped Silicon detector of GRIT with the iPACI preamplifier and a 64-channel digitizer. Z = 1 particles are discriminated with pulse shape analysis technique down to 2 MeV for protons, 2.5 MeV for deuterons and 3 MeV for tritons. The effect of the strip length due to the trapezoidal shape of the detector is investigated on both the N- and the P-side, showing no significant impact.

Research and development of the back-end electronics for the two-dimensional improved resistive plate chambers in CMS upgrade

To complement and ensure redundancy in the endcap muon system of the Compact Muon Solenoid (CMS) detector and to extend the Resistive Plate Chamber (RPC) system coverage, improved RPCs (iRPCs) with either orthogonal layer strips with one-end electronics or single layer strips with two-end electronics providing more precise time measurement will be installed in the very forward pseudorapidity region of $$|\eta |<2.4$$ . The iRPC readout system needs to support two-dimensional (2D) or two-end readout. In addition, it must combine detector data with Timing, Trigger and fast Control (TTC) and Slow Control (SC) into one data stream over a bi-directional optical link with a line rate of 4.8 Gb/s between the Front-End Electronics (FEE) and the Back-End Electronics (BEE). To fulfill these requirements, a prototype BEE for the iRPC 2D chamber has been researched and designed. A Micro-Telecommunication and Computing Architecture ( $$\mu $$ TCA)-based processing card was designed in this study to establish a prototype system together with a $$\mu $$ TCA crate. The Giga-Bit Transceiver (GBT) protocol is integrated to provide bi-directional communication between the FEE and BEE. A server is connected with the BEE by a Gigabit Ethernet (GbE) link for SC and a 10-GbE link for Data AcQuisition (DAQ). The Bit Error Rate (BER) test of the back-end board and a joint test with the iRPC 2D prototype chamber were performed. A BER of less than $$1.331\times {10^{-16}}$$ was obtained. The time measurement with a resolution of 3.05 ns was successfully realized, and detector efficiencies of 97.7% for longitudinal strips and 96.0% for orthogonal strips were measured. Test results demonstrate the correctness and reliability of the prototype BEE. The BEE prototype satisfies the requirements for the iRPC 2D chamber, and it worked stably and reliably during a long-term joint test run.

Towards a two-dimensional readout of the improved CMS Resistive Plate Chamber with a new front-end electronics

As part of the Compact Muon Solenoid experiment Phase-II upgrade program, new resistive plate chambers will be installed in the region at low angle with respect to the beam collision axis, in order to improve the detection of muons with a low transverse momentum. High background conditions are expected in this region during the high-luminosity phase of the Large Hadron Collider, therefore an improved-RPC design has been proposed with a new front-end electronics to sustain a higher particle rate capability and better time resolution. A new technology is used in the front-end electronics resulting in low achievable signal detection of 1–20 fC. Crucial in the design of the improved-RPC is the capability of a two-dimensional readout in order to improve the spatial resolution, mainly motivated by trigger requirements. In this work, the first performance results towards this two-dimensional readout are presented, based on data taken on a real-size prototype chamber with two embedded readout planes with orthogonal strips.

A comparative study between deflection compatible and strip method of slab analysis

This study aims to overcome the problems of deflection incompatibility that is observed on Hillerborg strip method of slab analysis. The study is started by developing an equation for load sharing capacity coefficient of the uniformly loaded slab in shorter and longer directions. It is done by combining Hillerborg strip method analysis basic assumption with the deflection compatibility at the intersection point of two orthogonal strips. The load function is then approximated to linear function by the principles of list-square curve fitting of a straight line to avoid complex analysis. Finally, span and support coefficients for each type of slab panel is calculated using SAP 2000 software and developed an excel sheet analysis template. The result obtained from the study shows that analysis of slab using Deflection Compatible (DC) method of slab analysis is more economical than that of the strip method of slab analysis. This occurred due to load distribution difference in Hillerborg strip method of analysis and the DC. The study result also shows that the DC method of slab analysis is safer than the coefficient method of slab analysis stated in the Ethiopian Building Code Standard.

Scanning of a Double-Sided Germanium Strip Detector

This work presents the results from the characterization of a Position-Sensitive Planar Germanium (PSPGe) detector. The PSPGe detector is a double-sided orthogonal strip detector consisting of 10x10 electrical segmentation along the horizontal and vertical directions. The characterization was performed using the coincidence setup between the PSPGe detector and the well-characterized scanning system employing the positron annihilation correlation principle. The scanning system consists of a Position Sensitive Detector (PSD) and 22Na positron source. The main objective of this study is to deploy PSPGe detector for future decay experiments at the Facility for Antiproton and Ion Research (FAIR), Germany. The measurements have been performed to find the depth of gamma-ray interaction in the planar segmented detector. The 2-Dimensional image obtained from the PSD has been used to find the depth of gamma-ray interaction in the planar strip detector using pulse shape analysis. In addition, the sensitivity of PSPGe detector has been investigated by calculating the rise-time from pulse shapes for the front and back strips of the detector.

Design and Analysis of Dual-Band Implantable Antennas Based on Effective Relative Permittivity Calculation

This article presents the design and analysis of dual-band implantable antennas based on effective relative permittivity calculation. First, the effective relative permittivity for a microstrip antenna inside lossy tissue is analyzed, helping establish the basis for the design of our proposed dual-band implantable antenna. The antenna operates in 1.4 GHz Wireless Medical Telemetry Service (WMTS) band and 2.45 GHz industrial, scientific, and medical (ISM) band under proper feeding scheme. The lower band with quarter-wavelength resonance is realized by introducing two shorting pins to orthogonal strips. As a disturbance between two arc-shaped tails with open end is introduced, it can achieve circular polarization (CP) radiation property. Meanwhile, the higher band with half-wavelength resonance is realized through the path connecting two asymmetric open-end tails, so as to achieve linear polarization (LP) radiation property. As such, a wide CP bandwidth of 10.38% in WMTS band and a wide impedance bandwidth of 21.3% in ISM band are achieved and in final verified in experiment.

Effect of fiber exclusion in uniaxial tensile tests of soft biological tissues

The effect of the exclusion of the compressed fibers in the identification of material parameters from uniaxial tensile tests on two orthogonal strips is investigated. The micro-structurally based constitutive model with two dispersion parameters developed by Holzapfel and his colleagues is utilized in the study. A new exclusion method, based on the coefficient reflecting the percentage of stretched fibers, is proposed. The material parameters are identified by using experimental data from 30 uniaxial tensile tests (5 donors, 6 strips per donor) and a genetic algorithm code that is capable to find the optimal set of parameters. The contraction of the strip width computed by using the hyperelastic model with the identified material parameters is compared to the experimental data for two human aortas (one from literature and one experiment, specific for this study), in order to show the accuracy of the identified model. The complex behavior of the thickness deformation of the strip is also obtained and compared to the experimental data derived from in-plane measurements and the incompressibility condition. Results show that the in-plane fiber exclusion is appropriate for aortic material characterization with uniaxial tensile tests, reducing very significantly the computational cost. At the same time, thickness growth of strips during uniaxial tests is possible, depending on fiber dispersion and orientation.

A Bandpass Filter–Polarizer Based on a Dielectric Multilayer with Strip Conductor Gratings

A new design of a multilayer bandpass filter is proposed, in which each resonator consists of two identical dielectric layers with parallel strip conductor gratings on their outer surfaces and an orthogonal strip conductor grating between the layers. The filter designed on the basis of crossed gratings works simultaneously as a polarizer transparent in a specified frequency band if the electric field vector of a wave is parallel to the outer strip conductors but reflects waves with an orthogonal polarization. The data from a numerical electrodynamic analysis of a 3D model of the proposed device agree well with the results of the measurements performed on the fifth-order filter–polarizer prototype with a relative bandwidth of 14% and a central frequency of 13.4 GHz. The microwave power loss in the filter passband is ~1.2 dB under parallel polarization of the electromagnetic wave and more than 40 dB under orthogonal polarization.

Effect of foundation shape and properties of the adjacent buildings on the railway-induced vibrations

Controlling the ground-borne vibrations affecting structures by changing the geometry and weight of foundation as an inexpensive and efficient method has rarely been considered by researchers. In this article, the effect of foundation geometry and weight built on different soil types on the induced vibration level in a building at the proximity of the railway track is investigated. To this end, a three-dimensional finite/infinite element model including soil, building and track is developed by considering the elastodynamic aspects. The accuracy of numerical modeling is demonstrated using the field tests. A comprehensive parametric analysis on three soil types (soft, medium and stiff) and specifications of building foundation is conducted. The obtained results unveiled that, contrary to the existing belief, foundation integration or increasing its weight does not necessarily end in the reduction in vibration level in building floors. Also, the transferred level of vibration to the building floors depends on the soil type, foundation properties and roof natural frequency. The findings highlight an orthogonal strip foundation in soft soil and single footing in medium and stiff soils transfer smaller vibration amplitude to floors. Additionally, the strip footing with greater weight on soft soil results in the highest vibration reduction in floors, while the single footing with lower weight on stiff soil has the same effect.

Multiband reciprocal polarization insensitivity electromagnetically induced transparency in metasurfaces

A reciprocal electromagnetically induced transparency (EIT) effect is proposed in the complementary metasurface structure, which is composed of metal orthogonal strips beside a silicon substrate. The EIT effect of reciprocity is obtained whether the incident wave propagates from the positive (+z) or reverse (−z) direction. A multiband EIT window is also obtained in the structure of horizontal strip and substrate silicon as bright mode and vertical strip as dark mode by the finite difference time domain (FDTD) method. The transmission mechanism is interpreted by giving the current surface and electric field distributions at certain frequencies. A polarization insensitive EIT can be realized theoretically due to the structure is symmetrical in the x and y directions. The effective permittivity of the structure was calculated by the method of inversion to reveal the transmission spectra. These results can be applied in many areas, such as multiband slow-light devices, active sensing and bidirectional devices.

3D printing of gaseous radiation detectors

Additive manufacturing techniques such as 3D printing offer unprecedented flexibility in realising intricate geometries. Fused-filament fabrication and high-precision inkjet 3D printing of metals and polymers was used to create functional composite structures, which were operated as radiation detectors. Electron avalanche multiplication in a 3D printed structure was achieved. We present an ionisation chamber and a coarse 2D readout anode with orthogonal strips, which were printed with PLA and graphite-loaded PLA . High-resolution inkjet 3D printing was used to create a Thick Gaseous Electron Multiplier (THGEM) . This represents the first realisation of a fully 3D printed structure achieving electron multiplication. Optical readout was used to quantify the gain factor of the structure and an image under X-ray irradiation was acquired. While the hole geometry of this prototype device inhibited high gain factors, it demonstrates that additive manufacturing is a viable approach for creating detector structures. The conventional manufacturing approach by photolithographic techniques will continue to dominate large size and volume production of MicroPattern Gaseous Detectors (MPGDs) but prototyping and results-driven detector optimisation may greatly benefit from the cost and time-effectiveness of 3D printing.

First application of a high-resolution silicon detector for proton beam Bragg peak detection in a 0.95 T magnetic field.

To report on experimental results of a high spatial resolution silicon-based detector exposed to therapeutic quality proton beams in a 0.95T transverse magnetic field. These experimental results are important for the development of accurate and novel dosimetry methods in future potential real-time MRI-guided proton therapy systems. A permanent magnet device was utilized to generate a 0.95T magnetic field over a 4×20×15cm3 volume. Within this volume, a high-resolution silicon diode array detector was positioned inside a PMMA phantom of 4×15×12cm3 . This detector contains two orthogonal strips containing 505 sensitive volumes spaced at 0.2mm apart. Proton beams collimated to a circle of 10mm diameter with nominal energies of 90MeV, 110MeV, and 125MeV were incident on the detector from an edge-on orientation. This allows for a measurement of the Bragg peak at 0.2mm spatial resolution in both the depth and lateral profile directions. The impact of the magnetic field on the proton beams, that is, a small deflection was also investigated. A Geant4 Monte Carlo simulation was performed of the experimental setup to aid in interpretation of the results. The nominal Bragg peak for each proton energy was successfully observed with a 0.2mm spatial resolution in the 0.95T transverse magnetic field in both a depth and lateral profiles. The proton beam deflection (at 0.95T) was a consistent 2 ±0.5mm at the center of the magnetic volume for each beam energy. However, a pristine Bragg peak was not observed for each energy. This was caused by the detector packaging having small air gaps between layers of the phantom material surrounding the diode array. These air gaps act to degrade the shape of the Bragg peak, and further to this, the nonwater equivalent silicon chip acts to separate the Bragg peak into multiple peaks depending on the proton path taken. Overall, a promising performance of the silicon detector array was observed, however, with a qualitative assessment rather than a robust quantitative dosimetric evaluation at this stage of development. For the first time, a high-resolution silicon-based radiation detector has been used to measure proton beam Bragg peak deflections in a phantom due to a strong magnetic field. Future efforts are required to optimize the detector packaging to strengthen the robustness of the dosimetric quantities obtained from the detector. Such high-resolution silicon diode arrays may be useful in future efforts in MRI-guided proton therapy research.

Novel fused-silica charge detection tile for particle detectors

Develop a novel charge-detecting tile for future large-scale liquid xenon TPC for searching for neutrinoless double-beta decay. Use advanced microelectronic technologies to fabricate small metal pads on a fused-silica wafer. The pads are chained into orthogonal strips, and the strips are isolated at the cross sections. The size of the pads defines the pitch between parallel strips and can be flexibly tuned according to any optimized dimension from future Monte Carlo studies. Such tile also has good potential to suppress the radioactivity and control electronics noise. Furthermore, its modular design allows to easily cover a large size. The design and performance have been demonstrated by a prototype tile, particularly by comprehensive tests in liquid xenon. A new design of charge detection tile and the fabrication technologies have been developed, which would be useful for future noble liquid detectors.

Spatial resolution of triple-GEM detectors

Gas Electron Multiplier (GEM) based detectors are widely used in numerous collider experiments and, in particular, at the Budker Institute of Nuclear Physics (BINP). In order to determine the best possible spatial resolution, the simulation of charged particle registration process is accomplished. The simulation shows that spatial resolution is definitely less than 20 μ m for applied operation configurations. The simulation of electron transport through single GEM and through GEM-cascade shows that an electron cluster is compressed by GEM holes and an effective transverse diffusion is reduced by approximately 15% as maximum. The experimental part of the work is devoted to the operability tests of the designed detector with orthogonal strips readout with a pitch of 250 μ m and the measurements of its characteristics including the dependence of gain on GEM-voltage, the registration efficiency and the spatial resolution. Spatial resolution of the studied detector is measured as 31 . 5 ± 0 . 9 ( s t a t . ) − 7 . 5 + 6 . 9 ( s y s t . ) μ m .

Dual crescent‐shaped slot antenna fed by circular polarisation into dual orthogonal strip lines

In this research, a novel single-layer dual crescent-shaped slot antenna is fed by circular polarisation into dual orthogonal strip lines for worldwide interoperability for microwave access (Wi-Max) and wireless fidelity (Wi-Fi) applications. One phase of the feed strip lines is shifted by 90° to enhance the circular polarisation. The surface current and the effect of changing the dimensions for the parameters are carefully studied to optimise the dimensions of the proposed antenna to satisfy the specifications of the wireless local area network/Wi-Fi standards of (2.4– 2.484)/(5.15–5.825) GHz and Wi-Max standards of (2.5–2.6)/(3.4–3.6)/(5.25–5.85) GHz. Several of the critical design parameters, such as return loss, radiation pattern, polarisation, axial ratio bandwidth, and gain are also investigated.