Transverse Configuration Research Articles

Experimental Evaluation of the Influences of Water on the Fracture Toughness of Mudstones with Bedding

The effect of water on fracture toughness in various modes of mudstones was investigated using semicircular bend (SCB) specimens exposed to three-point bendings. Natural mudstone specimens are obtained using a special coring method and are then classified into three types (A, B, and C) corresponding to three directions/configurations of bedding planes (divider, arrester, and transverse). The results show that the Type A (divider configuration) specimens possess the largest fracture toughness value for all tested modes and same soaking time, whereas the Type C (transverse configuration) specimens have the smallest one. By increasing soaking time, the fracture toughness in all three modes decreases and the fracture mechanism changes from brittle failure to ductile failure. Among them, the Type C specimens have the highest degree of degradation for each soaking time period. Regarding the fracture modes, the degradation degree ofKIcis higher than that ofKIIcfor all three types of mudstone specimens. In addition,KIIc/KIcratio increases when soaking time is extended. Furthermore, in the initial and short soaking time stages, the experimentalKIIc/KIcresults are consistent with theoretical findings from modified MTS criterion. However, after being soaked 300 minutes for three types of specimens, the test curves deviate from the theoretical curves. Analogously, the mixed-mode I/II ratio ofKefftoKIcis consistent with the theoretical values in the initial stage when the degree of damage is low. With soaking time increasing, the experimental curve is gradually deviated from the theoretical curve. When soaking time reaches 300 minutes, the deviation is substantial. And the test data for the Type-A specimens are observed to provide better agreements with theoretical predictions by modified MTS criterion than those for the other two types of specimens.

Improvement of spin-charge related magnetoelectric coupling and transport response of rare-earth based eco-friendly multiferroic nanocomposites

Eco-friendly, magnetoelectric LaFeO3–HoMnO3 nanocomposites are synthesized with different weight percentage, and highlighted their observed magnetoelectric coupling, electrical transport and dielectric properties. X-ray diffraction pattern and field emission scanning electron microscope images approve the formation of LaFeO3 and HoMnO3 phases without the presence of any extra phase. These composites reveal the strain mediated magnetoelectric effect with longitudinal (αE33) and transverse (αE31) configurations at lower frequency region under an external magnetic field. Maximum values of αE31 and αE33 are found to ~ 0.54 and ~ 0.31 mV/cm-Oe, respectively for 0.3LaFeO3–0.7HoMnO3 nanocomposites. The electronic transport has been examined by impedance spectroscopy technique for understanding the grain boundary and grain effects in resistive and capacitive behavior of the materials considering an idealized simulated circuit. Temperature dependent Nyquist plots show the non-Debye type phenomena as well as semiconductor in nature (i.e., negative temperature coefficient of resistance) of the materials. Electrical susceptibility reveals the domain motion of the system, which is corresponding to the electrostriction property. The electrical conductivity with frequency follows the Joncher’s single power law and it is controlled through large and small polaron tunneling model. The synthesized nanocomposites are a capable candidate to offer some helpful ideas for developing the lead free device applications.

Tunable Unidirectivity of Metal-Dielectric-Metal Plasmonic Nanoantennas With PT-Symmetric Potentials

Parity-time (PT) symmetric photonic systems have attracted much attention due to their intriguing properties and asymmetric behaviors. In this paper, we propose a plasmonic nanoantenna with PT-symmetric potential for unidirectional scattering functionality. The studied plasmonic nanoantenna is comprised of three metallic layers separated by two dielectric layers. Such kind of system, with the same coefficient of loss and gain in each of the two dielectric layers, holds the characteristic of PT symmetry. We show that the unidirectional scattering is obtained for the passive structure (i.e. κ=0, ), and the switching between forward and backward directionality can be achieved with a single element by changing the excitation wavelength, when the induced electric dipole (ED) and magnetic dipole (MD) modes satisfy the first or second Kerker conditions, respectively. In addition, we find that the forward-to-backward ratio spectra can be strongly affected by the non-Hermiticity parameter κ. In particular, it is possible to reverse the radiation direction at the same wavelength in a wide spectra band by adjusting κ. Moreover, putting the nanoantennas in an array of transverse configuration can efficiently narrow the main lobe angular beam width to be less than 6 degrees . These results contribute to the basic understanding of the optical properties of active-passive finite nanostructures with potential applications for the design of novel nanostructures displaying asymmetric and tunable responses.

Polarization-sensitive photoresponse of the CuSe/Se nanocomposite prepared by vacuum thermal deposition

We report on the generation of the polarization-sensitive photocurrent in the thin film of the CuSe/Se nanocomposite irradiated by femtosecond pulses of Ti:S laser. CuSe/Se bilayer consisting of nanocrystalline CuSe and amorphous Se films was obtained using successive deposition of Cu and Se on a glass substrate in the course of vacuum thermal evaporation. Synthesized bilayers were characterized using optical transmittance and Raman spectroscopy, optical, atomic force and scanning electron microscopy and X-ray diffractometry. It is demonstrated that in the longitudinal configuration, the photocurrent propagating along the plane of incidence is maximum for the p- and vanishes for the s-polarized excitation beam. In the transverse configuration, the photocurrent propagating perpendicular to the plane of incidence is an odd function of the polarization azimuth of the linearly polarized excitation beam and vanishes when it is either p- or s-polarized. We show that for an elliptically polarized excitation beam the polarity of the transverse photocurrent reverses when rotation direction of the electric field vector changes. Both longitudinal and transverse photocurrents are odd functions of the angle of incidence and can be explained in terms of the surface photogalvanic effect.

Effect of reinforcement grade and concrete strength on seismic performance of reinforced concrete bridge piers

This paper experimentally investigates the effect of the yield strength of longitudinal steel bars and concrete compressive strength on the seismic performance of reinforced concrete (RC) bridge piers. Cyclic loading tests of ten large scale RC bridge piers (including five circular section and five rectangular section) with different longitudinal steel bars grades (varying among HRB335, HRB500E and HRB600) and concrete compressive strengths (i.e., 32.6 MPa and 48.2 MPa) were conducted. Two different steel replacement methods, i.e. equivalent volume and equivalent strength replacements, were adopted for comparison. The seismic performance indexes lateral bearing capacity, deformation capacity, hysteretic energy dissipation and residual displacement were compared and analyzed. The test results indicate that all RC bridge piers show typical flexural failure mode while circular piers show better deformability and hysteretic energy dissipation than rectangular piers. Replacing conventional steel bars HRB335 with same amount of high-strength longitudinal steel bars (HRB500E and HRB600) (i.e. equivalent volume replacement) will increase the lateral bearing capacity (as expected), the yield displacement and the total deformation. Due to the increase in yield displacement, the displacement ductility, the viscous damping ratio and the residual displacement will reduce to some extent. Still, the RC piers reinforced with high-strength steel bars (HSSB) show larger plastic deformation and hysteretic energy dissipation because of greater total deformation and bearing capacity. The transverse reinforcement configurations of circular section provide better restraint to the buckling of longitudinal steel bars than rectangular section, thereby RC bridge piers with circular section show better deformability and hysteretic energy dissipation than rectangular section. The increase in concrete compressive strength reduces the yield displacement, thus enhances the hysteretic energy dissipation and viscous damping ratio at same total deformation. It is worth noting that the effect of concrete compressive strength on the seismic performance of rectangular section is more remarkable than circular section. Replacing conventional longitudinal steel bars with reduced amounts of high-strength steel bars (i.e. equivalent strength replacement) provided comparable flexural strength and deformation capacity, but reducing the residual displacement and hysteretic energy dissipation.

Weak measurement of the magneto-optical spin Hall effect of light

The spin Hall effect of light (SHEL) is a photonic version of the spin Hall effect in electronic systems and has been studied for more than 10 years. However, the lack of effective methods for dynamic modulation of spin-dependent splitting may hinder its applications. By introducing additional spin-orbit coupling of photons or nonreciprocal phase shift (NRPS), the magneto-optical Kerr effect may be one of the methods to alleviate the situation. Here, we experimentally reveal an enhanced and tunable SHEL in magneto-optical oxide thin films under the transverse magneto-optical Kerr effect configuration for the first time, to the best of our knowledge, which can be regarded as the magneto-optical SHEL (MOSHEL). We study the magneto-optical response of the multilayer structure and select the optimal structural parameters by the magneto-optical transfer matrix method. With a transverse magnetic field along opposite directions, an obvious SHEL shift difference of H-polarized light caused by NRPS is observed via a weak measurement method. With optimal parameters, the maximum measured shift difference of the SHEL achieves about 70 μm. The demonstrated MOSHEL phenomenon may accelerate the application of the SHEL in the field of spin photonics devices and precision metrology.

Experimental and Theoretical In Situ Spectral Magneto-Ellipsometry Study of Layered Ferromagnetic Structures

A method for processing of in situ spectral magneto-ellipsometry data has been developed to analyze planar ferromagnetic nanostructures. A multilayer model containing a ferromagnetic layer with two interfaces, a nonferromagnetic buffer layer, and a nonferromagnetic substrate has been tested within a new approach to the interpretation of magnetic-field-modulated spectral ellipsometric measurements involving the magnetooptical Kerr effect in the transverse configuration. In particular, the effect of the thickness of the ferromagnetic layer on the results of magneto-ellipsometric measurements has been analyzed. The measurements have been performed with polycrystalline Fe films with different thicknesses on a nonferromagnetic SiO2/Si(100) surface. The diagonal and off-diagonal components of the complex dielectric tensor in the spectral range of 1.38–3.45 eV have been determined by processing spectral magneto-ellipsometric data. The results have been compared to the available data obtained by other authors and to the calculation of the dielectric tensor of Fe within the density functional theory.

AXIAL BEHAVIOR OF RC COLUMNS RETROFITTED USING BAMBOO REINFORCED CONCRETE JACKET

Weak or damaged reinforced concrete columns need to be retrofitted in order to increase the strength capacity and ductility. Concrete jacketing is one of the most common techniques adopted for such purpose due to its relatively simple and low-cost application. However, the dependency on steel reinforcement in its use is still high and with the sustainability issues that are getting more important nowadays, the idea of bamboo as a replacement for steel as reinforcing bars in the concrete jacketing method has been investigated in this experimental study. A group of short reinforced concrete column specimens with axial load failure state were then retrofitted with a variety of longitudinal and transversal bamboo reinforcement configurations of concrete jacketing and subjected to further compression axial load test. The axial load-displacement behavior, axial strength capacity, and collapse mechanisms were recorded and analyzed. The outcomes showed that bamboo reinforced concrete jacket perform satisfactorily by restoring the axial load capacity and increasing ductility of column specimens providing that the bamboo stirrups spacing was set closer than that of the original column.

Longitudinal Magnetic Field Effects on (Y,Gd)Ba2Cu3O7−δ Coated Conductor With BaHfO3 Nanoparticles Fabricated by UTOC-MOD Method

To clarify the effects of longitudinal magnetic field (LMF) on Y0.77Gd0.23Ba2Cu3O7- δ coated conductors fabricated by the trifluoroacetic-acid based metal organic decomposition method with the ultra-thin-once-coating process (UTOC-MOD (Y,Gd)BCO-CCs), and to understand the contributions of BaHfO3 nanoparticles (BHO-NPs) to this, we investigated the critical current density J c under a wide range of temperature and magnetic field conditions. We found that J c in the LMF configuration increased compared to those in the in-plane transverse magnetic field configuration under whole conditions in samples both with (w/) and without (w/o) BHO-NPs. J c enhancement due to the LMF configuration was remarkable in the w/ BHO-NPs sample at higher temperatures, indicating that introduction of BHO-NPs to UTOC-MOD (Y,Gd)BCO-CC would be useful for LMF DC cable applications.

Study on thermo–hydraulics in a Pillow Plate Channel

In this work, the details of a numerical investigation carried out on the flow and heat transfer characteristics in the wavy pillow plate channels used for pillow plate heat exchangers have been presented. Water is used as the cooling medium. It is observed that in the thermally developing region, the recirculation zone contributes a higher proportion in the total heat transfer as compared to the thermally developed part. High heat transfer is observed in the developing region is due to the lower average temperature of the hot recirculating zones. Further, a parametric study is conducted by varying the geometric parameters of the channel. The study is based on the transversal and equal pitch pillow plate configurations. The numerical results are validated against the experimental results available in the literature. Based on the numerical results, a heat transfer correlation is developed. Also, a sensitivity analysis is carried out to quantify the effect of various geometric parameters and Reynolds number on the thermo – hydraulic performance of the pillow plate channel.

Torsional capacity investigation of reinforced concrete beams with different configurations of welded and unwelded transverse reinforcement

AbstractAn experimental study is carried out to test 25 reinforced concrete (RC) beams in order to investigate the torsional behavior of the beams using welded and unwelded transverse reinforcement. Four different transverse reinforcement configurations were considered: ordinary, continuous circular spiral, continuous rectangular spiral, and continuous advanced rectangular spiral configuration. Welded configuration includes welding the hoops to the longitudinal reinforcement at their intersections. Three different spacing of 200, 150, and 100 mm were used. The experimental torsional capacity results are compared with the theoretical values determined by the ACI 318–14 code, Eurocode‐2, fib model code2010 and other available equations in the literature. The results showed that the welding effect varies based on the transverse reinforcement configuration and spacing and the maximum improvement in the ultimate torsional capacity of RC beams is obtained in the specimens made with continuous circular spiral stirrups. Furthermore, the ACI‐318, Eurocode‐2, fib model code2010 and other equations available in the literature are generally conservative in predicting the ultimate torsional strength of welded and unwelded RC beams with continuous transverse reinforcement but the predicted torsion moments obtained using Eurocode‐2 and fib model code2010 are closer to the test results.

Magnetic Shielding of Open and Semi-closed Bulk Superconductor Tubes: The Role of a Cap

In this paper we investigate the magnetic shielding of hollow and semi-closed bulk superconducting tubes at 77 K. We first consider the properties of a commercial Bi-2223 tube closed by a disk-shaped cap placed against its extremity. The results are compared with those obtained on a bulk large grain Y-Ba-Cu-O (YBCO) tube produced by buffer-aided top seeded melt growth. In this process, the disk-shaped pellet and the tubular sample are grown together, resulting in a tube naturally closed at one extremity. The field to be shielded is either parallel or perpendicular to the main axis of the tube. The experimental results are compared with the results of finite element numerical modeling carried out either in two dimensions (for the axial configuration) or three dimensions (for the transverse configuration). In the axial configuration, the results show that the shielded volume can be enhanced easily by increasing the thickness of the cap. In the transverse configuration, the results show the critical role played by the superconducting current loops flowing between the tube and the cap for magnetic shielding. If the tube and the cap are separated by a non-superconducting joint or air gap, the presence of a cap leads only to a small improvement of the transverse shielding factor, even for a configuration where the gap between the cap and the tube contains a 90° bend. The cap leads to a significant increase in the transverse shielding when the cap and the tube are naturally grown in the same process, i.e., made of a continuous superconducting material. The experimental results can be reproduced qualitatively by 3-D numerical modeling.

Internal transverse reinforcement configuration effect of EB/NSE-FRCM shear strengthening of RC deep beams

This paper presents an experimental study carried out on the structural performance of shear-critical reinforced concrete (RC) deep beams internally reinforced with two different stirrups configurations; i.e. aligned and unaligned with the fabric-reinforced cementitious matrix (FRCM) strips. The test matrix involved two unstrengthened (reference) beams and twelve strengthened deep beams tested under three-point bending. Three test variables were investigated: (a) the configuration of the internal transverse reinforcement (ITR), (b) the type of FRCM fabric (carbon, glass, and polyparaphenylene benzobisoxazole, PBO), and (c) the strengthening technique (externally bonded, EB, and near-surface embedded, NSE). Experimental results demonstrated an effective application of the FRCM in improving the load capacities (Pmax) of deep beams; however, its performance depends on the test variables. The NSE-FRCM provided an inherent anchorage that prevented the premature debonding of the FRCM composite, which was a standard failure mode in the externally bonded FRCM strengthened beams. Finally, a simple strut and tie model (STM) is used to predict the load capacities of the deep beams strengthened with different FRCM systems and resulted in a satisfactory prediction with an average Pth/Pex ratio of 1.11 and a standard deviation of 5.7%.

Determination of the contribution of a phonon and a magnetic field to the chemical properties of the hydrogen molecule using the density functional theory approach

The chemical properties of the hydrogen molecule under a magnetic field in a transverse configuration and in the presence of phonons are investigated using the Density Functional Theory. The hydrogen molecule is considered as a two-electron system confined in a Coulomb type parabolic external potential. It is shown that the electron density and the chemical hardness are not influenced by the presence of the phonon but strongly depend on the magnetic field. The latter preserves the intrinsic chemical properties of the molecule but weakens the electron-electron interaction. On the other hand, the chemical potential and the energy of the system are found to strongly depend on the phonon dynamics. It is also seen that phonon dynamics lead to an increase in the internal energy even at a constant critical value of the magnetic field.

Fluid flow, heat transfer and entropy generation analyses of turbulent forced convection through isotropic porous media using RANS models

Abstract Turbulent fluid flow, heat transfer and entropy generation through isotropic porous media were investigated utilizing two RANS models, i.e., RNG k - e and SST k - ω . Circular, longitudinal elliptical and transverse elliptical cross-sectional configurations were analyzed with symmetrical boundary conditions for the upper and lower lines and periodic boundary conditions for the back and front lines. Evaluation of the temperature contours indicated two low-temperature regions behind the solid rods of the transverse elliptical cross-sectional configuration exist. For a given specific normalized pressure gradient, dimensionless turbulence kinetic energy, Nusselt number, and heat transfer efficiency, the RNG k - e model resulted in more reliable results for the dimensionless turbulence kinetic energy at low Reynolds numbers when compared with the SST k - ω model. Using the thermal analysis of the three cross-sectional configurations investigated, the longitudinal elliptical resulted in higher heat transfer efficiencies when compared with the circular and transverse elliptical cross-sectional configurations. When the influence of the turbulence effects were included in the entropy generation rate, a second law of thermodynamics analysis indicated that the longitudinal elliptical cross-sectional configuration resulted in a lower entropy generation rate when compared with the circular and transverse elliptical cross-sectional configurations. Combining the results of the first and second law analyses for the three cross-sectional configurations, it is apparent that isotropic porous media consisting of the longitudinal elliptical cross-sectional configuration can simultaneously result in a high heat transfer efficiency and low entropy generation rate.

Solid state ASE from an oligomer (HOTF) in polymethyl methacrylate

Solid state laser material based on oligomer 9,9,9′,9′,9″,9″-hexakis(octyl)-2,7′,2′,7″-trifluorene (HOTF) doped poly methyl methacrylate (PMMA) was fabricated. The absorption spectrum showed only one band at 355 nm with different concentration ratios (7–12 mM); thus the broad absorption band could be attributed to the α-phase formation. In addition, there was no new band detected at the end of the spectrum as the concentration increased. This indicates the absence of the β-phase formation for all concentrations used. On the other hand, HOTF exhibited two distinct emission bands at 420 and 470 nm for 7 mM concentration. When the concentration was increased to 9 mM, the intensity of the band 470 nm increased. Further increase the concentration to 12 mM, the intensity of the band at 420 nm totally vanished and there was only one band at 470 nm. Therefore, the band at 470 could be attributed to excimer state. However, the results revealed that there is a strong correlation between quantum yield of fluorescence and fluorescence life-time, absorption cross section, and emission cross section. Under pulsed laser excitation. The ASE spectrum of HOTF has been obtained using a transverse cavity configuration where the conjugated HOTF was pumped by the third-harmonic of Nd:YAG nanosecond pulsed laser (λex = 355 nm). We demonstrate that HOTF in the solid state could produce an ASE peak at 420 nm. The obtained results were compared with the HOTF and a conducting polymer poly (9,9-dioctylfluorene) (PFO)in the liquid state.

Quantum transport properties in single crystals of α−Bi4I4

We report the magnetotransport properties of $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{Bi}}_{4}{\mathrm{I}}_{4}$ single crystals, which have a crystal structure similar to that of the quasi-one-dimensional topological insulator $\ensuremath{\beta}\text{\ensuremath{-}}{\mathrm{Bi}}_{4}{\mathrm{I}}_{4}$. Prominent Shubnikov--de Hass oscillations and weak antilocalization effect are observed in all measured samples. The angular-dependent magnetoresistance indicates that the behavior of Shubnikov--de Hass oscillations is two-dimensional (2D) in $n$-type samples, while it is three-dimensional (3D) in $p$-type samples. First-principles calculations show that the $n$-type samples have a 2D Fermi surface, while the $p$-type samples have a 3D Fermi surface. Considering the similar carrier density and mobility, we infer that the transport behaviors in both types of samples come from bulk electron contributions. In addition, a large negative magnetoresistance with a transverse configuration is observed in the $n$-type sample A1. All the results indicate that $\ensuremath{\alpha}\text{\ensuremath{-}}{\mathrm{Bi}}_{4}{\mathrm{I}}_{4}$ is an important material platform for investigation of novel and interesting phenomena. Our work may also provide important references for studying the topological surface transport properties in $\ensuremath{\beta}\text{\ensuremath{-}}{\mathrm{Bi}}_{4}{\mathrm{I}}_{4}$ in the future.

Inorganic-organic hybrid nanocomposites: Magnetoelectric coupling, dielectric and AC electrical response

Room temperature magnetoelectric coupling, magnetic field dependent dielectric and ac electrical properties of xLa0.7Sr0.3MnO3 – (1 − x) Poly(vinylidene fluoride) (x = 0.5, 0.6 and 0.7) nanocomposites have been investigated. The magnetoelectric voltage coefficients are found to ∼0.25 and ∼0.16 mV/cmOe for transverse and longitudinal configurations. Dielectric constants for all the compositions are increased with increase in magnetic field. Magnetodielectric value is estimated to ∼16% due to the magnetostriction property of the samples. The fitted value of Nyquist plots reveals the dominant role of the grain boundaries of La0.7Sr0.3MnO3 nanoparticles and modified grain boundaries due to Poly(vinylidene fluoride) in the samples. With the application of magnetic field the relaxation frequencies are shifted towards the higher frequency region attributing to the magnetic field dependent relaxation process in the system.

Initial stability and stress distribution of ankle arthroscopic arthrodesis with three kinds of 2-screw configuration fixation: a finite element analysis

BackgroundArthroscopic ankle arthrodesis (AAA) is recognized as the standard treatment for the end-stage ankle arthritis. Two-screw configuration fixation is a typical technique for AAA; however, no consensus has been reached on how to select most suitable inserted position and direction. For better joint reduction, we developed a new configuration (2 home run-screw configuration: 2 screws are inserted from the lateral-posterior and medial-posterior malleolus into the talar neck) and investigated whether it turned out to be better than the other commonly used 2-screw configurations.MethodsIn this study, we investigated three kinds of 2-screw configurations: 2 “home run”-screw configuration (group A), crossed transverse configuration (the screw is inserted from the medial malleolus into the anterior talus and the other from the lateral tibia maintains posterior talus, group B), and 2 parallel screw configuration (2 parallel screws are inserted from the posteromedial side of the tibia into talus, group C). The effects of the above three insertions on the loading stress of the tibio-talar joint were comparatively analyzed with a three-dimensional finite element model.ResultsGroup A was better than groups B and C in respect of stress distribution uniformity and superior to both groups B and C in anti-flexion strength and anti-internal rotation strength. Group A was slightly worse than group C but better than group B in anti-dorsiflexion and anti-valgus and varus strength.ConclusionsTwo “home run”-screw configuration facilitates the reduction of anterior talus dislocation of end-stage ankle arthritis. Our finite element analysis demonstrates the configuration is superior to crossed transverse and parallel configuration for arthroscopic ankle arthrodesis in terms of stress distribution and initial stability.

Dispersion Characteristics and Phase Index of One-Dimensional Magnetized Ferrite Photonic Crystals in Transverse Magnetization Configuration for TE Modes

The dispersion characteristics and phase index of magnetized one-dimensional ferrite photonic crystals in transverse magnetization for transverse electric modes are investigated. The dispersion relation and expression for phase index are derived by using transfer matrix method. The effects of structural parameters such as external magnetic fields, filling factor, and β on dispersion properties and phase index are investigated. The dielectric nature of the considered magnetized ferrite photonic crystal structure is demonstrated. Also, the band structure for ω < 1.5 × 1010 rad s− 1 is strongly affected by external magnetic fields. It is observed that phase index occurs in the form of lobes and is found to be controlled by external magnetic field, β, and filling factor.