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Generally, in reinforced concrete (RC) core wall buildings, the formation of one plastic hinge at the base is preferred; this is called the single plastic hinge (SPH) approach. During a severe earthquake, this approach results in significant moment demand in the upper regions of the wall due to the effect of higher modes of vibration. This study considered RC core walls of 30-, 40- and 50-storey buildings, designed using a response spectrum analysis. The SPH, dual plastic hinge (DPH), triple plastic hinge (TPH) and extended plastic hinge (EPH) approaches were examined using fibre element models and non-linear time history analysis. The DPH and TPH approaches respectively contain one and two plastic hinges at the upper levels of the wall in addition to the base plastic hinge. The effect of the locations of the upper plastic hinges on the seismic response of the core wall was investigated. The results showed that there is not a distinct level for the upper plastic hinge location to minimise the envelope of different demand quantities simultaneously. The curvature demand of the middle plastic hinge in the TPH case was higher than the base curvature demands. Reducing the resistant moment at the wall base by reducing the reinforcement ratio can help to balance curvature demands along the height of the TPH model.

Background: Al is the promising candidate for deep UV and longer wavelength range plasmonic applications. But it is difficult to have the pure aluminium nanostructure as it is easily oxidized, forming a thin layer of Al2O3. In this paper, we have evaluated the field enhancement of oxide layer on metallic shell (Al-Al2O3 and Au-Al2O3) for single and dimer core-shell configuration and showed potential of the oxide layer in SERS. Methods: The Finite Difference Time Domain (FDTD) has been used to evaluate the LSPR and field enhancement of single and dimer Al-Al2O3 and Au- Al2O3 nanostructure. Results: The results exhibit the tunable plasmon resonance on varying the inner and outer radii of the Al2O3 shell. A redshift and decrease in enhancement were observed as shell thickness increases, whereas on increasing the core size, the enhancement increases in the case of Au-Al2O3 and decreases in Al- Al2O3 due to quadrupole contribution. But on comparing the Au-Al2O3 with Al-Al2O3 for the same particle size, Al-Al2O3 shows larger enhancement because Au has to compete with its interband transition. Conclusion: By optimizing the thickness of the shell and core size, it can be concluded that an ultrathin shell of Al2O3 can give higher enhancement. With Al as a core metal, the enhancement increases as compared to Au-Al2O3. Since a single Al-Al2O3 nanoshell has shown a huge enhancement we have considered the multimer configuration of two identical nanoshells. Due to coupling between two nanoshells a huge increase in enhancement factor ~1012 was observed for Al-Al2O3 dimer nanoshell in the UV region.

Core body temperature (CBT) is a basic physiological parameter that reflects the level of human metabolism and is therefore clinically important for the diagnosis of various diseases. The traditional method of CBT evaluation based on heat flux is susceptible to errors caused by horizontal heat flux and the sensor is usually large in size. In this study, a novel miniaturized sandwich-like CBT monitoring sensor (SCBTS) based on negative temperature coefficient (NTC) temperature sensor and heat flux sensor was constructed. The sandwich-like structure minimized the effect of horizontal heat flux and reduced ambient temperature disturbance. In addition, a novel numerical method was explored to predict CBT during unsteady heat flux. Effectiveness of SCBTS was verified by finite element method (FEM) simulation, mock-up experiments and human experiments. The proposed sensor was effective within the range of human body temperature fluctuations (35°C-42°C) with an average error of 0.02°C on the hot plate. In human trials, resting experiments (eight participants for 13 trials) showed 0.02°C average difference with a 95% CI of [-0.16, 0.12]°C. Furthermore, the sensor showed distinct temperature changes in different periods using exercise experiments (6 participants). The proposed SCBTS continuously monitors temperature without causing inconvenience to the subject, therefore, it is highly suitable for application.

Air-cored planar inductors play an important part in enabling high power-density, low weight, and low-profile design of high-frequency switched-mode power applications. However, the absence of ferromagnetic core in these inductors makes the magnetic field distribution in them different from that in the cored inductors and the transformers. Due to this difference, the conventional winding loss calculation models like the one-dimensional Dowells model are not suitable for these inductors. Therefore, in this paper, an improved two-dimensional analytical winding loss model for multi-layered air-cored inductors with a single-turn per layer is proposed based on the fundamental electromagnetic field solution incorporating the two-dimensional boundary values and the edge effect in its formulation. The finite element method (FEM) simulation and experimental results validate the proposed model's high-accuracy and engineering precision over a wide frequency range (up to 10MHz). Furthermore, the results ensure the proposed analytical model to be an efficient, easier, and better substitute for the FEM based calculation approach.

As an essential component in power applications, magnetic cores and their design play an important role in achieving high efficiency and high power density. Accurate measurement of the core loss is important for inductor and power converter optimization. Loss measurement depends on exactly determining the phase angle between the voltage and the current. However, measurement errors can be introduced due to the discrepancies in propagation delays in the voltage and current sensors. In addition, the propagation delay is frequency dependent, but has a large influence in the MHz range and above. Previously, several methods have been proposed to compensate for this discrepancy but they are time consuming and can result in large measurement errors. In this paper, a characterization method for core loss based on a vector network analyzer and an impedance converter is proposed to accurately measure the phase discrepancies between voltage and current sensors. The proposed method is experimentally verified up to 15 MHz with a three-coil test setup.

The composition of Earth's mantle, when compared to experimentally determined partitioning coefficients, can be used to constrain the conditions of equilibration - pressure P, temperature T, and oxygen fugacity fO2 - of the metal and silicates during core-mantle differentiation.This places constraints on the thermal state of the planet during its accretion, and it is tempting to try to use these data to estimate the heat content of the core at the end of accretion. To do so, we develop an analytical model of the thermal evolution of the metal phase during its descent through the solid mantle toward the growing core, taking into account compression heating, viscous dissipation heating, and heat exchange with the surrounding silicates. For each impact, the model takes as initial condition the pressure and temperature at the base of the magma ocean, and gives the temperature of the metal when it reaches the core. The growth of the planet results in additional pressure increase and compression heating of the core. The thermal model is coupled to a Monte-Carlo inversion of the metal/silicates equilibration conditions (P, T, fO2) in the course of accretion from the abundance of Ni, Co, V and Cr in the mantle, and provides an estimate of the core heat content at the end of accretion for each geochemically successful accretion. The core heat content depends on the mean degree of metal-silicates equilibration, on the mode of metal/silicates separation in the mantle (diapirism, percolation, or dyking), but also very significantly on the shape of the equilibration conditions curve (equilibration P and T vs. fraction of Earth accreted). We find that many accretion histories which are successful in reproducing the mantle composition yield a core that is colder than its current state. Imposing that the temperature of the core at the end of accretion is higher than its current values therefore provides strong constraints on the accretion history. In particular, we find that the core heat content depends significantly on the last stages of accretion.

To enhance the inferior energy-absorption performance of a hydraulic support during coal mine rock burst, which leads to failure and damage, a framework including a kind of corrugated laminated energy-absorbing component on the top beam of the hydraulic support is developed. First, triangular, trapezoidal and sinusoidal corrugated core energy-absorbing structures are designed, and their mathematical models are established. Second, three kinds of corrugated core components are optimized to obtain the suitable structural parameters, and based on the findings, the energy-absorption characteristic curves of the three kinds of corrugated core components are obtained through a simulation analysis. The results show that the sinusoidal corrugated core exhibits the best energy-absorption effect among the single-layer corrugated components. Among the two-layer and four-layer corrugated core components, the triangular corrugated core arrangement is the optimal arrangement. The energy absorption of the three kinds of corrugated core components is correlated with the delamination. The results of the experiment and simulation are consistent. This study provides a theoretical basis and experimental reference for the design of energy-absorbing components for an anti-impact hydraulic support.

The space mining market is expected to grow in the future with water, gold, and platinum as just a few of the resources that could be accessible in the Moon or in near-Earth asteroids. To achieve this mining capability, sandwich composites offer an optimum structure for space mining vehicles due to their relatively high strength and stiffness compared to their weight. The challenge of designing such structures is often hampered by the lack of design approaches for practicing engineers in the mining industry usually lacking the composite material expertise or access to significant test capabilities. Expanding the use of sandwich composite materials into this industry requires selection charts that fully define the material system for a design engineer. Currently there is no methodology that systematically allows a design engineer to define a material system that uses carbon fiber reinforced plastics with aluminum honeycomb cores. The purpose of this paper is to introduce novel selection charts that allow an engineer to define the number of plies, stacking sequence, core thickness, and core density of a sandwich composite based off the moment carrying capacity. An example implementation of this approach is conducted using a carbon-fiber/epoxy with an aluminum alloy 5052 core. The selection charts developed with this approach are than validated with experimental analysis in accordance with ASTM D7249 (Standard Test Method for Facing Properties of Sandwich Construction by Long Beam Flexure). Experimental results show strong correlation with the selection charts by predicting the available moment and the mode of failure. Such selection charts will help facilitate wider use of these materials into industries that do not currently use them. Additionally, a novel numerical modeling approach for thick section sandwich composites using 3D finite elements is introduced. This approach shows how sandwich composite facesheets can be modeled with standard 3D elements instead of elements that support layers. Such an approach allows access to a wider variety of elements and is conducive to rapid design iterations when topological changes are occurring such as in a research and development environment. It is shown that numerical results correlate well with experimental data when using a linear-elastic isotropic core model with bilinear isotropic plasticity.

Accurate measurement of electrical currents cannot be done when the core of current transformers (CTs) is saturated. One of the reasons that causes saturation of a CT is the activation of the auto-reclose function for the circuit breaker. When the circuit breaker is switched off, a residual flux will remain in the CT core, and when the circuit breaker is reconnected, this residual flux may cause saturation of the CT core. It is necessary to remove the residual flux in an auto-reclosing scheme. In the auto-reclosing scheme, due to the short time interval between each reclosing shot of the circuit breaker, only methods that have a high-speed operation should be used to mitigate the residual flux to prevent CT core saturation. This paper introduces a fast and complete demagnetization method based on Jiles-Atherton magnetic modeling to mitigate the residual flux in the CT core. The advantages of this method are high-speed performance, independent of the CT characteristics, high accuracy and high reliability against the secondary open circuit. To evaluate the efficacy of the proposed method, software simulations and laboratory experiments are performed on a 63kV, 300A/5A CT. The results are presented and analyzed.

This study aims to analyze the influence of vortex motion in a reverse Stairmand cyclone separator by using LES model. The mathematical analysis indicated that the energy dissipation and the flow characteristics of incompressible fluid are directly related to on the vortex motion. The results of the Q criterion-based iso-vortex surface could well reflect the tendency of the vortex structure, in which the iso-vortex surface exhibited a distorted distribution rather than around the center axis. At the turning point of velocity vector, vortices were formed and developed, and the point was the center of the local vortex core. In addition, the vortex formed an irregular annular region around the wall at the bottom of vortex finder. The vortex structure near the dust hopper presented a strong distortion. Moreover, there were two rotating flow in the opposite direction within the dust hopper. These phenomena would affect the separation performance, which was significance to cyclone separator.

The conducted numerical and physical hypervelocity impact testing illustrated that foam-core sandwich panel can effectively serve as a multifunctional component of the spacecraft, providing weight-...

This paper reports the control method for the core power of the China initiative Accelerator Driven System (CiADS) facility. In the CiADS facility, an intense external neutron source provided by a proton accelerator coupled to a spallation target is used to drive a sub-critical reactor. Without any control rod inside the sub-critical reactor, the core power is controlled by adjusting the proton beam intensity. In order to continuously change the beam intensity, an adjustable aperture is considered to be used at the Low Energy Beam Transport (LEBT) line of the accelerator. The aperture size is adjusted based on the Proportional Integral Derivative (PID) controllers, by comparing either the setting beam intensity or the setting core power with the measured value. To evaluate the proposed control method, a CiADS core model is built based on the point reactor kinetics model with six delayed neutron groups. The simulations based on the CiADS core model have indicated that the core power can be controlled stably by adjusting the aperture size. The response time in the adjustment of the core power depends mainly on the adjustment time of the beam intensity.

Apertures generally exist in the sandwich structures attributing to mechanical connection and lightweight, which might induce failure of such structures. Thus, it is required to realize the impact of aperture on mechanical behaviors of sandwich structures. If transverse shear deformations are unable to be described accurately, the reasonable prediction of dynamic behaviors of the form-core sandwich plates with apertures will meet severe challenges due to a large difference of transverse shear modulus at the adjacent layers. Thereby, such issue is less studied by using the efficient models and experimental testing, so an alternative sinusoidal-type finite element formulation is to be proposed to precisely predict dynamic response of the form-core sandwich structures with apertures. The proposed finite element formulation can meet beforehand compatible conditions of transverse shear stresses at the interfaces of adjacent laminates. In order to appraise strictly capability of the proposed model, experimental tests on natural frequencies of three groups of specimens with different apertures have been carried out. Moreover, four specimens in each group are tested to reduce the testing errors, which is less reported in the published literature. In addition, three-dimensional Finite Element Method (3-D FEM) is also selected to account for the good performance of the present model. Finally, the impact of aperture diameter on the natural frequencies of the sandwich structures is both experimentally and numerically investigated, which can serve as a reference for other researchers.

Type II fiber Bragg gratings (FBGs) inscribed with femtosecond (fs) laser possess significant potential for high temperature sensing. In this work, we propose and demonstrate a method for fabricating a parallel-integrated ultra-short type II FBG (PI-US-FBG) by using an fs laser point-by-point technology. The PI-US-FBG, featuring by an ultra-short grating length of 80 m, consists of six identical FBGs parallel-inscribed into a fiber core at different radial positions in the same cross section. The fabricated PI-US-FBG exhibits a broadband Gaussian-shape spectrum with a low reflectivity of ~10%, an ultra-low out-of-band insertion loss of 0.01 dB, and a large full width at half maximum bandwidth of 9.4 nm. Moreover, this PI-US-FBG could be used as a high temperature sensor with a wide measurement range from 25 to 1000 C, and an excellent linearity was achieved with a dual-wavelength differential detection. The temperature sensitivity could be increased from 0.00316 to 0.00945 (dB/C) by enlarging the wavelength spacing of the tunable laser. In addition, two cascaded PI-US-FBGs were used to precisely measure the temperature field distribution in a CO2 laser spot with a very high spatial resolution of 100 m. Hence, the proposed PI-US-FBGs could be used for a large-scale fiber sensor network, especially in future distributed temperature measurement with a high spatial resolution.

Few-mode fibers and coupled-core multi-core fibers are attractive transmission media for space-division multiplexed transmission systems as they enable a high spatial channel multiplicity whilst sustaining the current standard cladding diameter. This paper compares space-division multiplexed recirculating loop transmission using either a 3-mode few-mode fiber or a 3-core coupled-core multi-core fiber. After analyzing the spectral attenuation properties of both fibers, we investigate the wavelength and transmission distance dependence of the transmission channel characteristics. We find that the channel memory length is shorter and mode-dependent loss is lower in the coupled-core multi-core fiber, which can be attributed to the fundamental mode-structure differences between the two fiber types. This leads to a higher data rate at similar transmission distance for the coupled-core multi-core fiber.

This study describes the impact of postprocessing methods on the calculated parameters of tip vortices of a wind turbine model when tested using Particle Image Velocimetry (PIV). Several vortex identification methods and differentiation schemes are compared. The chosen methods are based on two components of the velocity field and its derivatives. They are applied to each instantaneous velocity field from the dataset and also to the calculated average velocity field. The methodologies are compared through the vortex center location, vortex core radius and jittering zone. Results show that the tip vortex center locations and radius have good comparability and can vary only a few grid spacings between methods. Conversely, the convection velocity and the jittering surface, defined as the area where the instantaneous vortex centers are located, vary between identification methods. Overall, the examined parameters depend significantly on the post-processing method and selected vortex identification criteria. Therefore, this study proves that the selection of the most suitable postprocessing methods of PIV data is pivotal to ensure robust results.

We investigate recirculating transmission of a wideband S-, C- and L-band signal in a 4-core fiber. We transmit 552 x 25 GHz spaced, 24.5 GBd channels. covering more than a 120 nm bandwidth from 1487.8 nm to 1608.33 nm through each core of the multi-core fiber (MCF) which has the same 125m cladding dimeter as standard single-mode fiber. We first use PDM-16QAM modulation and measure performance at distances up to 3001 km, corresponding to 43 spans of the 69.8 km MCF. At this distance we measure a decoded throughput of 319 Tb/s or 342 Tb/s when estimating from the generalised mutual information (GMI). Extending the transmission distance to 8027 km, a selection of PDM-QPSK modulated channels across the spectrum were received with an average GMI estimated data-rate of 82.8 Gb/s. These results show that wideband transmission including the S-band has the potential to increase data-rates in long-haul optical fiber transmission. Further, our experiment confirms that 125 m diameter MCFs can multiply transmission capacity whilst offering benefits of resource sharing and integration, expected in SDM systems.

The analytical modeling of parasitic capacitances in inductors is commonly based on the energy-conservation law. Yet, in order to calculate the equivalent capacitances of inductors, the floating voltage potential of magnetic core is required to be preknown in all previous modeling methods. This letter proposes an analytical method for calculating the parasitic capacitances of the inductors with low-resistivity cores, which does not require any prior knowledge of the floating core potential. The proposed modeling method can be extended to the transformers as well as multiterminal magnetic devices. The experimental results verify the effectiveness of the proposed method.

Accurate parameters are critical to permanent magnet synchronous machine (PMSM) drive. This paper investigates accurate flux linkages, inductances and PM flux linkage estimation for PMSM with core loss compensation. With conventional model, core loss will induce the flux linkage error especially in the deep saturation region. Hence, this paper firstly proposes a novel differential modeling technique to compensate core loss, in which differential measurement is defined as the incremental value calculated from the actual measurements under two different speed conditions. With multiple differential measurements, the flux linkage error due to core loss can be compensated to improve the accuracy of flux linkage estimation. Then, the polynomial based flux linkage model is employed to derive the PM flux linkage and cross-saturation inductances. Self-inductances are estimated from the flux linkage model using least squares method. The proposed approach can accurately estimate parameters without the need of core loss data and can improve the estimation accuracy especially in deep saturation region, which is validated on a laboratory interior PMSM and compared with existing methods under various operating conditions.

We proposed a silver-coated 45 radiated tilted fiber grating (45 RTFG) based interferometer, in which the 45 RTFG is working as a beam splitter and a coupler, and the light transmitting in the fiber core is radiated out and resonant in the cladding radial cavity formed by the fully coated silver film, which forms multiple beam interference. We have theoretically and experimentally investigated the proposed fiber interferometer in terms of polarization-dependent transmission spectra, the free spectral range (FSR), spectral visibility and sensing characteristics. Due to the single polarization radiation feature of 45 RTFG, only S-polarized light could form the multiple beam interference and P-polarized light would pass through the grating with low loss. And the FSR of the proposed fiber interferometer is around 6.8 nm, which is determined by the 125 m cladding diameter. The theoretical results show that the spectral visibility of interference is proportional to the coupling efficient of 45 RTFG and when the coupling efficient reaches 0.92, the spectral visibility is the maximum. In the experiment, the fiber interferometer formed by the 45 RTFG with 11 dB polarization extinction ratio has the spectral visibility of 26 dB. Moreover, we have also investigated the temperature, strain and twist characteristics of the proposed interferometer. The experimental results show that the transmission peak has a red shift with increasing temperature, with a sensitivity of 10 0.1 pm/C; The strain causes a blue shift for the transmission peak with -0.42 0.01 pm/ sensitivity, and the twist sensitivity reaches 22.408 0.2 dB/rad. The proposed silver-coated 45 RTFG based interferometer has an in-fiber and compact structure, which can be potentially used for optical fiber sensing.

This paper overviews novel magnetic-field-shifting techniques for enhancing the torque in a new class of asymmetric rotor pole interior permanent magnet (AIPM) machines. The principle for torque enhancement is introduced firstly. AIPM topologies are then categorized in terms of asymmetries and symmetricities of PM configuration and rotor core geometry. Subsequently, the merits and demerits of various AIPM rotor topologies in each category are analyzed and compared. Finally, torque capabilities of selected AIPM machines are compared.

Screw conveyors are widely employed in industrial fields for conveying bulk materials. The shearer drum which uses the screw conveying principle is responsible for excavation and conveying coal particles onto the chain conveyor. Screw conveyor performance is affected by potential factors, such as the blade axial tilt angle and style, core shaft form and diameter. The effect of blade axial tilt angle on the conveying performance was investigated with the help of DEM. In the case of the screw conveyor, the mass flow rate, and particle axial velocity increased with increasing positive axial tilt angle, and declined with increasing negative axial tilt angle. In the case of the drum, the mass flow rate, particle axial velocity, and loading rate first increased and then decreased with increasing positive axial tilt angle, and decreased with increasing negative axial tilt angle. These results can be considered as a benchmark for screw conveyor and drum structural designs with axial tilt screw blades.

Soft magnetic powder cores are attractive due to their loss at medium frequency. However, the performance of electrical equipment is affected by temperature increase by the heat of core losses. In this paper, the magnetic properties of nanocrystalline powder core, amorphous powder core, X-Flux (Fe-Si), Sendust (Fe-Si-Al), and ferrite are measured and compared in the range of 25 °C to 125 °C from 20 kHz to 100 kHz. The discussed magnetic properties include the temperature dependent coercive field, initial permeability, inductance factor, saturation flux density, and core loss. The results show that magnetic properties depend on temperature and frequency. In comparison, the nanocrystalline powder core has the best temperature stability and relatively low core loss among the five materials, so it can be well used at broad temperature and medium frequency.

In this paper, we report a facile process to fabricate CuO/Au core/shell nanowires, where CuO core and Au shell were prepared by thermal oxidation and sputtering, respectively. The as-prepared CuO/Au nanowires are highly sensitive surface-enhanced-Raman-scattering (SERS) substrates, which can detect methylene blue down to a very low concentration of 10−13 M. The major advantages of SERS substrates based on CuO/Au core/shell nanowires compared with others SERS substrates are the high sensitivity, uniformity, and purity due to the absence of any organic surfactants in the synthesis process.

The use of in-fiber core-to-cladding coupling components for thermal heating purposes has been well assessed in the last decades within the development of fiber optic devices for flow measurements and water thermal conductivity calculation. In these devices, light travelling in the fiber core is transferred into the cladding and absorbed by a metallic layer surrounding the fiber, with the consequent resistive heating generation. Here we demonstrate for the first time the use of a Turn-Around-Point (TAP) Long Period Grating (LPG) as resonant core-to-cladding light coupling mechanism for the fabrication of a highly efficient heating device based on metallic coated Fiber Bragg Grating (FBG). A properly designed TAP LPG was fabricated by means of point-to-point UV laser and spliced to a 150 nm thick Au-coated FBG. The heating efficiency characterizations of the final device were analyzed, in both air and water, by evaluating the temperature increase in the gold layer surrounding the FBG at incremental values of the injected power. Collected results confirm that the use of LPGs involving the excitation of higher order cladding modes provides an excellent transferring mechanism of the fiber core light into the cladding, which in turn guarantees very high thermal heating efficiency to the final device. Moreover, by comparing such results with the performance of other in-fiber core-to-cladding coupling components already presented in literature, it was found that the TAP LPG-based device exhibits an actuation efficiency 2.5 times greater, thus resulting the most effective and highly performing solution for energy transfer to the metallic overcoat.

The United Arab Emirates is currently building and operating four units of the APR-1400 developed by a South Korean vendor, Korea Electric Power Corporation (KEPCO). This paper attempts to perform APR-1400 reactor core analysis by using the well-known two-step method. The two-step method was applied to the APR-1400 first cycle using the open-source nodal diffusion code, KOMODO. In this study, the group constants were generated using CASMO-4 fuel transport lattice code. The simulation was performed in Hot Zero Power (HZP) at steady-state and transient conditions. Some typical parameters necessary for the Nuclear Design Report (NDR) were evaluated in this paper, such as effective neutron multiplication factor, control rod worth, and critical boron concentration for steady-state analysis. Other parameters such as reactivity insertion, power, and fuel temperature changes during the Reactivity Insertion Accident (RIA) simulation were evaluated as well. The results from KOMODO were verified using PARCS and SIMULATE-3 nodal core simulators. It was found that KOMODO gives an excellent agreement.

We propose a dual-polarized leaky-wave antenna (LWA) with orthomode based on a metallic square waveguide, for broadband endfire radiation applications. Several double-sided slots acting as radiation elements are notched on the waveguide to produce an endfire pattern. To overcome the restriction associated with the endfire radiation condition of a linear array, a metallic core periodically loaded with pins is used to control the dispersion of the proposed double-sided-slot waveguide. By optimizing the height distribution of the loading pins along the longitudinal direction using a cosine function, stable endfire radiation can be achieved over a broad operating band. Moreover, dual-polarized radiation can be automatically implemented because of the rotational symmetry of the proposed LWA. Furthermore, two rectangular waveguides connected with a square waveguide are used as the orthomode transducer (OMT) of the proposed LWA. The numerical and experimental results verify that dual-polarized endfire radiation is achieved in the frequency range of 7.6-9.1 GHz with an isolation of higher than 45 dB. The realized gain achieved is in the range of 13-15 dBi with a cross-polarization level of below -30 dB.

This manuscript comes up with a unique GaAs-filled elliptical core-based hexagonal cladding PCF that manifests ultra-high birefringence (Br) and non-linear coefficient (NLC). The distinct optical characteristics of the PCF are thoroughly simulated and analyzed by the finite element method (FEM) through the commonly available COMSOL Multiphysics software. The simulated findings confirm that using the high refractive index (RI) advantages of GaAs at the effective wavelength of 1.55 μ m , a high Br of 0.92 , as well as an ultra-high NLC of 2.06 × 10 6 W − 1 K m − 1 and zero-dispersion can be obtained. Besides, several primary optical properties, namely numerical aperture (NA), confinement loss (CL), power fraction (PF), dispersion, etc. are also discussed and investigated in depth in the propounded article. The zero-dispersion characteristic, as well as the high Br and ultra-high NLC of the advanced PCF model, make it a worthy candidate for extensive purposes, including biochemical detection, high nonlinear applications, supercontinuum generation, optical communication and other sensing applications.

We propose a battery-free temperature monitoring device that can be fitted inside the ear for an accurate body temperature measurement of a subject. The proposed application consists of two primary systems: 1) a battery-free temperature sensing ultra-high-frequency radio frequency identification sensory tag and 2) an auxiliary energy harvesting system, which enhances the sensing device's measurement accuracy and precision. The system can record changes in the localized body temperature of authenticated users with an average latency of 501 ms. The assembly demonstrated a temperature average accuracy of ± 0.14 °C operating at 866 MHz. The system performance demonstrated high stability and repeatability of reported temperature measurements. The device's dimension is a form factor that can easily fit in a front shirt pocket, with a wire tethered earbud temperature sensor. The system is developed to make sensor measurements without requiring a battery for the device. Measurements are made remotely as users pass by checkpoints installed throughout a building. The device is a cost-effective solution for monitoring body temperature in work environments.

Two regional climate models (RCMs) participating in the CORDEX–Coordinated Output for Regional Evaluations (CORDEX-CORE) project feature a dipole-type rainfall bias during March–May (MAM) and September–November (SON) over central equatorial Africa (CEA), consisting of positive bias in west central equatorial Africa (WCEA) and negative bias in east central equatorial Africa (ECEA). One is the Regional Model version 2015 (REMO2015) and the other is the fourth version of the Regional Climate Model (RegCM4-v7). RCMs are nested in three Earth system models (ESMs) from phase 5 of the Coupled Model Intercomparison Project (CMIP5), and in the reanalysis ERA-Interim, at ∼25-km spacing grid resolution. This study highlights misrepresented underlying physical processes associated with these rainfall biases through a process-based evaluation. Both RCMs produce a weaker Congo basin cell, associated with a weaker land–ocean zonal surface pressure gradient. Consequently, less water vapor enters the region, and little is transported from WCEA to ECEA, resulting in higher moisture availability in the west than in the east. This leads to an unevenly distributed moisture across the region, favoring a stronger atmospheric instability in WCEA where the moist static energy (MSE) anomalously increases through an enhanced latent static energy (LSE). Moisture arrives at a slower pace in ECEA, associated with the weak cell’s strength. The intensity of ascent motions in response to the orographic constraint is weak to destabilize atmospheric stability in the lower layers, necessary for initiating deep convection. Therefore, the convection is shallow in ECEA related to underestimating the MSE due to the reduced LSE.

In recent years, sandwich structures have been increasingly developed as advanced composite structural components. Different core designs of sandwich structure have been proposed and investigated to improve the structural performance in aerospace industry, which is generally made of aluminium, carbon fibre-reinforced plastics (CFRP) and glass fibre-reinforced plastics (GFRP). It is a challenging task to reduce the impact influence on vibration behaviour as core structure, while still maintains the excellent strength and structural performance. This paper aims to investigate the free vibration characteristics of the spherical-roof contoured cores (SRCC) as core structure in sandwich panel. The two novel core designs, three types of materials and two boundary conditions were investigated using the finite element method. It was shown that glass fibre-reinforced plastic material could have much more mode numbers on common and novel core designs comparing with metal and CFRP materials. It was concluded that the metal, CFRP and GFRP materials had nearly same trend as the mode increased. Moreover, natural frequency, maximum magnitude and mode shape were determined in this study.

Based on the concept of rapidly repair after earthquake, a new type of double yield points assembled buckling-restrained brace (DYP-ABRB) with replaceable inner core is proposed. The inner core is composed of two I-shaped plates with different lengths, the peripheral component is composed of channel steel and I-shaped plates, and the unbonded layer is the gap between the core and the peripheral component. The constitutive tectonic composition and force transmission of the DYP-ABRB was carried out. The key parameters in the constitutive model of the material used in the core were determined through the material test, and the obtained parameters were input into the finite element software ABAQUS, which can truly simulate the performance of the finite element model of the brace under cyclic loading. On the base of determining the constitutive model parameters of materials, the design method of the model size and the finite element modeling of the brace, numerical simulation analysis of seismic performance was carried out on six DYP-ABRBs with replaceable inner core. The influences of different parameters, such as weakening width of inner cores, material of inner cores, length of inner cores and form of inner cores on the bearing capacity and hysteretic energy dissipation performance of braces were studied. The results show that the DYP-ABRB exhibits obvious two-stage behavior, and has stable and symmetrical hysteretic performance. All peripheral components are basically kept in the elastic state after loading, which shows that the brace has good post-earthquake repairability. After the earthquake, the brace only needs to disassemble the high-strength bolts and extract the core from both ends for replacement, and the peripheral components can still be used continuously, which greatly reduces the construction waste and economic losses, and has a good application prospect.

We report an air-stable tetraradicaloid based on a rarely explored perylenequinonoid (PQ) core, namely, tetrabenzo-annulated tetracyclopenta[b,e,k,n]perylene (TBCP), which has a quadruple helical s...

We propose and demonstrate a selectively microfluidic-infiltrated method for the group birefringence regulation in a microstructured optical fiber. Meanwhile, an Optical Frequency Domain Reflectometry (OFDR) with an equivalent resolution of 0.6 Hz or 10-6 RIU is utilized to characterize its polarization separation and group birefringence change. By selectively infiltrating a fluid with a high thermal-optic coefficient into twin air holes nearby the silica fiber core, tunable group birefringence is observed and measured by polarization separation in beat frequency domain. Moreover, due to the co-effects of the filled and unfilled fiber segments, the twin critical zeros of the overall group birefringence are observed at 16.5 and 43.0, respectively. The unique position exchange of LP01x and LP01y presents at the twin critical zeros, which is investigated via the OFDR technique as well. Therefore, by combining the unfilled fiber segment with negative group birefringence and filled fiber segment with positive group birefringence, dual zeros in group birefringence are achieved with position exchange of the LP01x and LP01y peaks in beat frequency domain. Our demonstration provides potentials in flexible regulation and real-time observation of the group birefringence in microstructured optical fiber.

In recent decades, the application of concrete-filled single and double skin steel tube columns in moderate and high rise structures has expanded rapidly hence understanding the influence of various parameters on the axial load characteristics of composite columns has become a top priority. A parametric investigation of the action of concrete-filled single skin and double skin tube columns under the influence of axial load is presented in this research. A numerical finite element analysis with the help of ABAQUS/CAE 6.14 software is carried out considering the various parameters such as varying grade of steel tube and concrete core, steel tube thickness, ratio of diameter-to-thickness of columns and slenderness ratio of column specimens. All of the variables studied have a significant impact on the CFST (single skin and double skin) columns' axial compressive strength, and these factors are addressed in detail in this work. The study revealed that growing ratio of diameter to thickness reduces the ultimate load capacity of both type of composite columns. It is also observed that when there is an increase in the steel and concrete grade, the loading capacity of the columns gets enhanced. Also, reduced length-to-diameter ratio is found to improve the axial loading capacity of columns. The axial strength of concrete filled single skin tube columns (CFST) is found to get highly influenced with the variations of all the different parameters as compared to concrete filled double skin tube columns.

Stiffness and strength of sandwich plate vary depending on similar (SI) or dissimilar (DSI) material element (faceplate or core) and laser weld geometry. The issues of I-core sandwich plate characteristics are essential to attain practical sandwich plate application. Hence, research on different material properties and T-joint weld characteristics of I-core sandwich steel plate presents a positive understanding of various character factors that affect sandwich plate bending performance. In this paper, the I-core sandwich steel plate characteristic was investigated using finite element analysis (FEA). The 3-point bending with a fine meshing, interaction of elements, and load applied was kept constant. The partition size at the laser weld geometry is smaller, and the partition size continuously grows when further away from the weld geometry. The result shows that a combination of weak and strong material on either element will reduce I-core sandwich's stiffness and strength unless strong material is assigned at the faceplate and core. Moreover, there is a significant change when rootgap is present. This influencing the centric and eccentric of the weld. The weld width produces a perfect bending as wholesome T-joint, yet to achieve such traits is impossible in reality but possible when the weld length is closer to the length of the core. The exploration of these characteristics in response to I-core sandwich steel plate holds a good response in engaging for the multiple variables that affect the plate's stiffness and strength.

The suppression of high-intensity blob structures in the scrape-off layer (SOL) by ion-cyclotron range of frequencies (ICRF) power, leading to a decrease in the turbulent fluctuation level, is observed first in the Experimental Advanced Superconducting Tokamak (EAST) experiment. This suppression effect from ICRF power injection is global in the whole SOL at EAST, i.e. blob structures both in the regions that are magnetically connected to the active ICRF launcher and in the regions that are not connected to the active ICRF launcher could be suppressed by ICRF power. However, more ICRF power is required to reach the full blob structure suppression effect in the regions that are magnetically unconnected to the active launcher than in the regions that are magnetically connected to the active launcher. Studies show that a possible reason for the blob suppression could be the enhanced E r × B shear flow in the SOL, which is supported by the shaper radial gradient in the floating potential profiles sensed by the divertor probe arrays with increasing ICRF power. The local RF wave power unabsorbed by the core plasma is responsible for the modification of potential profiles in the SOL regions.

We present a numerical analysis of noise performance improvement of the erbium-doped fiber amplifier by flatting the mode field intensity distribution within the interaction region of erbium ions. Three different refractive index types of erbium-doped fiber were used to study the effect of the pump mode intensity distribution on noise performance. The results show that taking advantage of the depressed refractive index erbium-doped fiber which has a flat mode distribution in the fiber core, the maximum reduction of nearly 0.53 dB for noise figure was achieved across the full C-band. Based on the center depressed refractive index profile, the noise figure was further decreased by about 0.1 dB by reducing the doping radius to 0.71 μm. Finally, maintaining the same gain level of ∼38.3 dB, a NF reduction of ∼0.63 dB was realized by introducing the center depressed refractive index profile and narrowing the erbium doping region. It is suggested that our investigation shows great potential for improving the noise performance of the erbium-doped fiber amplifier.

The quality of cement-treated soil columns is normally assured based on the unconfined compressive strength qu of core samples. qu of core samples varies spatially and the statistical parameters of qu (i.e., mean µqu, variance [Formula: see text], and autocorrelation distance θqu) are adopted in quality assurance procedures. The statistical parameters of qu evaluated from the core sample strengths have a statistical uncertainty depending on the statistical sample size. The present study investigates the influence of the statistical sample size on the evaluation of overall strength of a cement-treated soil column. A probabilistic framework in which a Bayesian inference analysis and a finite element method analysis are incorporated is used to calculate the overall strength while simultaneously considering the statistical uncertainty and spatial variability of core strength. The probabilistic framework is briefly described, and a parametric analysis is performed to investigate the influence of the statistical sample size on the evaluation of the overall strength of a full-scale column. The numerical results show that the sample size and spatial correlation influence the variability of the overall strength, and the influence can be reasonably described using an equivalent number of independent data.

In the present article, a detailed numerical deformation and failure analysis of sandwiched structures with different face sheet materials and core design has been carried out. Different face sheets materials ranging from aluminium alloys to composites such as carbon/epoxy and kevlar/epoxy fixed on different types of core were analyzed. Sandwiched structure with aluminium alloy face sheet showed minimum deformation of the impacting point, large impactor recoil and least strain energy absorption. Whereas carbon/epoxy face sheet showed large deformation of the impacting point for all the core designs. Employing the carbon/epoxy face sheet, the impactor recoiled only with square and hexagonal core design while the strain energy absorption was minimum for square and maximum for circular core designs. Kevlar/epoxy face sheet also showed large deformation of the impacting point for all the types of honeycomb core designs. The impactor recoiled very minimally for square core design and there was no recoil for the hexagonal and circular core. Kevlar/epoxy face sheet showed maximum displacement of the impacting point and strain energy absorption for the circular core. Thus, it can be said that sandwiched structure with a carbon/epoxy face sheet appeared to be the best choice in terms of energy absorption during the impact. The present study showed improvement in ballistic behaviour of sandwich structure with composite face sheet as compared to metallic face sheet in terms of energy absorption.

Optical fibre tapers have recently been intensively studied for a variety of applications, including telecommunications, medical, and biochemical sensing. In this research, we fabricate photonic crystal fiber taper without collapsing air holes and describe how steering air-cladding increases the evanescent-field sensitivity of microstructure fibres. The enhancement of the microstructure fibre's performance is based on the decrease of the diameter of the fiber core to a minimal width by tapering, where a specified part power of light is directed by an evanescent field passing through the air holes in the axial cladding. The initial structure of the fiber with outer diameter of 5 μm was reduced (100, 80,60) um for improving the very limited. The guided core mode and axial air holes have a high intensity overlap at 1.55 m wavelength. Some simulation results have been achieved by using the COMSOL multiphysics program. It used to design the photonic crystal fiber large-mode area and with different taper waist diameter and find mode intensity distributions guiding of 1550 nm inside the optical crystal fiber.