Out-of Plane Research Articles

Shear properties evaluation of a truss core of sandwich beams

The open-cell cores of sandwich structures are locally bonded to the face layers by means of adhesive resin. The sandwich structures composed of different parent materials such as carbon fibre composites (laminated face layers) and metallic core (aluminium truss core) brings the need to closely analyse their adhesive connections which strength is dominated by the shear stress. The presented work considers sandwich beams subjected to the static tests in the 3-point bending with the purpose of estimation of shear properties of the truss core. The main concern is dedicated to the out-of plane shear modulus and ultimate shear stress of the aluminium truss core. The loading of the beam is provided by a static machine. For the all beams the force - deflection history is extracted by means of non-contact optical deflection measurement using PONTOS system. The mode of failure is identified for each beam with the corresponding applied force. A flexural rigidity of the sandwich beams is also discussed based on force - displacement plots.

Variation of magnetic easy direction of bcc structured ferromagnetic films up to thirty spin layers

Third order Heisenberg Hamiltonian was employed to determine the effect of number of spin layers on magnetic easy direction. 3-D graph of energy versus stress induced anisotropy and angle was plotted to find magnetic easy and hard directions. First values of stress induced anisotropy corresponding to minima and maxima of this 3-D plot were determined. Then the graph of energy versus angle was plotted at each of these stress induced anisotropy values in order to determine magnetic easy and hard directions. The same approach was applied to find the easy and hard directions for different values of spin exchange anisotropy. Magnetic easy direction gradually rotates from out of plane to in plane direction of the film, as the number of spin layers is increased from 10 to 30. The magnetic anisotropy energy (energy difference between magnetic easy and hard directions) gradually increases as the number of layers is increased. However, the angle between easy and hard directions doesn’t change considerably in this range of thickness. Our theoretical data agree with experimental data obtained by some other researchers. Easy axis oriented magnetic thin films are useful in magnetic memory devices due to the higher magnetic anisotropy and higher energy density.

Cyclic tensile-compressive tests on thin concrete boundary elements with a single layer of reinforcement prone to out-of-plane instability

The growing need for residential housing in Latin American countries has led to the construction of reinforced concrete buildings with wall thicknesses as low as 8–10 cm. Such walls have typically only a single layer of vertical rebars and are therefore particularly susceptible to out-of-plane failure. In order to investigate the response of the corresponding wall boundary elements, twelve reinforced concrete members with a single layer of vertical rebars were tested under tension–compression cycles. The objective was to gain insight into the parameters governing wall instability and out-of-plane failure, namely the thickness, reinforcement ratio, and eccentricity of the longitudinal rebars with respect to the member axis. This paper summarises the results of the test program, where the specimens' response is analysed also at the global and local levels. The results show that the crack pattern has an important influence on the out-of-plane behaviour and the conditions leading to out-of-plane failure are described. Furthermore, the differences between members with a single layer of vertical rebars and members with two layers are discussed. The influence of the parameters considered in the experimental program is addressed, showing that sections with small thickness and large reinforcement content are more prone to out-of-plane failures. Finally, predictions given by existing models are compared to the new experimental data. The entire data set is publicly available.

335 Procedural Competency in Ultrasound-Guided Peripheral Intravenous Catheter Insertion in a Pediatric Emergency Department

To evaluate if there is a threshold number of encounters after which providers reliably perform ultrasound guided peripheral intravenous (USGPIV) catheter placements in children with a high success rate. A secondary aim was to analyze complication rates of USGPIV catheters placed by providers. As part of a quality improvement program, a database was maintained for all USGPIV encounters in our emergency department (ED) from June 2011 to May 2017. Our ED is located within a free-standing tertiary care children’s hospital and sees over 90,000 children annually. The name of the ED practitioner attempting placement and whether it was successful was recorded for all USGPIV encounters. Patient electronic medical records were reviewed for the reason for IV removal. ED practitioners included attending physicians, pediatric emergency medicine (EM) fellows, nurses, and pediatric and EM residents. All USGPIVs were placed by a single-operator using dynamic ultrasound guidance in an out-of plane approach. The probability of successful IV placement at each encounter was calculated using Microsoft Excel (2008). These probabilities were plotted versus encounter number to graph a best-fit logarithmic regression. Using this regression equation, the number of encounters needed to achieve a probability of success of 90% was calculated. The probability of a complication after each successful USGPIV placement was also calculated, plotted versus encounter number, and overlayed with a logarithmic regression line. We analyzed 3,047 encounters involving 88 providers. Of those, 2,860 (94%) were successful and 187 (6%) were unsuccessful. 35 providers had 10 or more encounters. The probability of successfully placing an USGPIV increased as providers had more experience placing USGPIVs (Figure 1). After 2 encounters, the probability of success was 80%. After 10 encounters, the probability of success reached 88%. At 14 encounters, the probability of success was 90%. IV removal reason was available for 1,178 encounters. 850 (72%) were removed because they were no longer needed. 260 (22%) had complications, and 68 (6%) were unintentionally dislodged. Complications included infiltration, phlebitis, line occlusion, and “other” (eg, pain or bleeding at site). Complication rates were calculated and graphed for 31 providers who had at least 5 encounters. There was no statistically significant relationship between the number of encounters per provider and complication rates (R2 =0.015). Our data suggests a threshold number of encounters after which providers reliably place USGPIVs in children with a high success rate. In our single institution study, a 90% success rate was achieved after an average of 14 encounters. Additionally, we found an overall low complication rate of 22%, and no change in complication rates as providers gained more experience.

A Strain-Driven Antiferroelectric-to-Ferroelectric Phase Transition in La-Doped BiFeO3 Thin Films on Si.

A strain-driven orthorhombic (O) to rhombohedral (R) phase transition is reported in La-doped BiFeO3 thin films on silicon substrates. Biaxial compressive epitaxial strain is found to stabilize the rhombohedral phase at La concentrations beyond the morphotropic phase boundary (MPB). By tailoring the residual strain with film thickness, we demonstrate a mixed O/R phase structure consisting of O phase domains measuring tens of nanometers wide within a predominant R phase matrix. A combination of piezoresponse force microscopy (PFM), transmission electron microscopy (TEM), polarization-electric field hysteresis loop (P-E loop), and polarization maps reveal that the O-R structural change is an antiferroelectric to ferroelectric (AFE-FE) phase transition. Using scanning transmission electron microscopy (STEM), an atomically sharp O/R MPB is observed. Moreover, X-ray absorption spectra (XAS) and X-ray linear dichroism (XLD) measurements reveal a change in the antiferromagnetic axis orientation from out of plane (R-phase) to in plane (O-phase). These findings provide direct evidence of spin-charge-lattice coupling in La-doped BiFeO3 thin films. Furthermore, this study opens a new pathway to drive the AFE-FE O-R phase transition and provides a route to study the O/R MPB in these films.

Influence of cone angle on the performance of a wafer cone flowmeter

The present study explores the effect of upstream disturbances like a single 90°bend, double 90° bends (in plane and out of plane) on the performance of wafer cone flowmeters with same beta ratio (β) of 0.77 but different half cone angles (α) of 30° and 45°. The influence of these disturbances on the upstream and downstream axial velocity (u) profiles are studied experimentally. The orientation effects, if any, are also studied experimentally. The minimum upstream distances required to get a fully developed flow for these disturbances vary with type of upstream disturbance, beta ratio (β) and half cone angle (α) of the wafer cone flowmeter. The study is carried out for a single phase flow with air as working medium at high Reynolds number (ReD = 144000). From the results obtained from this study, it may be concluded that the wafer cone flowmeter with a beta ratio (β) of 0.77 and a cone angle of 30° requires less upstream distance compared to the wafer cone flowmeter with a beta ratio (β) of 0.77 with a cone angle of 45° for all the disturbances under consideration.

Growth and magnetic properties of Co0.6Zn0.4Fe1.7Mn0.3O4 thin films on silicon

Integration of ferrite thin films of CoFe2O4 with silicon was an essential step for the development of magnetic and microwave micro-electro-mechanical system (MEMS) devices. This paper reports about the integration of Zn and Mn co-doped CoFe2O4 (Co0.6Zn0.4Fe1.7Mn0.3O4) thin films on silicon wafer surface. The films were deposited by spin coating technique and subsequently annealed at 600°C (thickness ∼200nm) and 700°C (thickness ∼150nm). Higher values of in plane remanance ratio (33–35%) compared to out of planes (5–13.5%) ones indicate the in plane orientation of the easy axis of magnetization driven by the shape anisotropy of the thin film structure. Upon rise in annealing temperature, coercivity for longitudinal Kerr hysteresis loop increases from 164Oe to 227Oe and that for the transverse hysteresis Kerr loop increases from 244Oe to 586Oe.

Perpendicular magnetic anisotropy in ZnMnS ultra-thin films caused by structural cleavage

Half tetragonal ZnMnS crystal based on three single layers of Zn, S and Mn was investigated by including spin–orbit coupling in full potential linearized augmented plane waves method. We show that the magnetic anisotropy exhibits a strong dependence with structural cleavage, which induces an out-of plane magnetic easy axis. The perpendicular magnetic anisotropy was calculated to be 1890.9µeV. The anti-ferromagnetic behavior is displayed between Mn atoms having a magnetic moment of ±3.57μB with c(2×2) magnetic configuration. The results indicate that ZnMnS compound has interesting optical and magnetic properties for spintronics applications.

Out of plane superconducting Nb/Cu/Ni/Cu/Co triplet spin-valves

The critical temperature of a triplet superconducting spin valve depends on the effectiveness of the conversion of singlet pairs in the superconductor into triplet pairs which can penetrate a ferromagnet and so drive a strong proximity effect. Here, we compare the out-of plane field dependence of the critical temperature in transition metal triplet spin valves with otherwise equivalent samples in which the singlet-triplet converting spin mixer ferromagnet layer is omitted. We report a significant field-dependent difference between the samples, which is consistent with a magnetisation orientation dependent spin mixing efficiency in the spin valve.

Study on dynamic deformation synchronized measurement technology of double-layer liquid surfaces

Accurate measurement of the dynamic deformation of double-layer liquid surfaces plays an important role in many fields, such as fluid mechanics, biomechanics, petrochemical industry and aerospace engineering. It is difficult to measure dynamic deformation of double-layer liquid surfaces synchronously for traditional methods. In this paper, a novel and effective method for full-field static and dynamic deformation measurement of double-layer liquid surfaces has been developed, that is wavefront distortion of double-wavelength transmission light with geometric phase analysis (GPA) method. Double wavelength lattice patterns used here are produced by two techniques, one is by double wavelength laser, and the other is by liquid crystal display (LCD). The techniques combine the characteristics such as high transparency, low reflectivity and fluidity of liquid. Two color lattice patterns produced by laser and LCD were adjusted at a certain angle through the tested double-layer liquid surfaces simultaneously. On the basis of the refractive indexes difference of two transmitted lights, the double-layer liquid surfaces were decoupled with GPA method. Combined with the derived relationship between phase variation of transmission-lattice patterns and out-of plane heights of two surfaces, as well as considering the height curves of the liquid level, the double-layer liquid surfaces can be reconstructed successfully. Compared with the traditional measurement method, the developed method not only has the common advantages of the optical measurement methods, such as high-precision, full-field and non-contact, but also simple, low cost and easy to set up.

Spectroscopic ellipsometer study of correlation of out of plane and in-plane plasmons in silver nanoislands with annealing induced growth

In-plane and out of plane plasmons' study in Ag metallic nanoparticles films deposited onto glass substrate using pulsed laser ablation technique and annealed from 100-400 °C temperature range has been presented using spectroscopic ellipsometer (SE). Effective dielectric constants of nanoislands thin films have been obtained by fitting psi and delta measured from SE which contain the information about annealing induced changes in morphological properties. A simultaneous fitting of p-polarized and s-polarized reflection spectra strengths the uniqueness of applied set of oscillators. Behavior of LSPR peak shift has been discussed in the frame of Modified-Yamguchi model. A shape dependent calculation of plasmon linewidth and further comparison with measured linewidth has been made to predict preferred direction of the annealing induced growth of the film. Morphological facts are also confirmed by FESEM images of the films. Both shifts indicate the dewetting of the film and isolation of nanoparticles. Grain boundary diffusion assisted two-dimensional growth of three dimensional particles is confirmed by present analysis.

Anomalous Hall Coulomb drag of massive Dirac fermions

Dirac fermions are actively investigated, and the discovery of the quantized anomalous Hall effect of massive Dirac fermions has spurred the promise of low-energy electronics. Some materials hosting Dirac fermions are natural platforms for interlayer coherence effects such as Coulomb drag and exciton condensation. Here we determine the role played by the anomalous Hall effect in Coulomb drag in massive Dirac fermion systems. We focus on topological insulator films with out-of plane magnetizations in both the active and passive layers. The transverse response of the active layer is dominated by a topological term arising from the Berry curvature. We show that the topological mechanism does not contribute to Coulomb drag, yet the longitudinal drag force in the passive layer gives rise to a transverse drag current. This anomalous Hall drag current is independent of the active-layer magnetization, a fact that can be verified experimentally. It depends non-monotonically on the passive-layer magnetization, exhibiting a peak that becomes more pronounced at low densities. These findings should stimulate new experiments and quantitative studies of anomalous Hall drag.

Pressure-induced iso-structural phase transition and metallization in WSe2

We present in situ high-pressure synchrotron X-ray diffraction (XRD) and Raman spectroscopy study, and electrical transport measurement of single crystal WSe2 in diamond anvil cells with pressures up to 54.0–62.8 GPa. The XRD and Raman results show that the phase undergoes a pressure-induced iso-structural transition via layer sliding, beginning at 28.5 GPa and not being completed up to around 60 GPa. The Raman data also reveals a dominant role of the in-plane strain over the out-of plane compression in helping achieve the transition. Consistently, the electrical transport experiments down to 1.8 K reveals a pressure-induced metallization for WSe2 through a broad pressure range of 28.2–61.7 GPa, where a mixed semiconducting and metallic feature is observed due to the coexisting low- and high-pressure structures.

A lateral paracarotid approach for ultrasound-guided stellate ganglion block with a linear probe.

Recent reports suggest that ultrasound-guided stellate ganglion block (SGB) is safer and more accurate than classic SGB by the using the surface anatomical landmark. However, previous reports concern the classic paratracheal approach using a small specialized curved probe, which may not be appropriate in some patients. The authors have attempted several approaches, including paratracheal, trans-thyroidal, lateral paracarotid, and lateral approaches, to find a safe and suitable method for real-time ultrasound-guided SGB using a standard high-frequency linear probe. A total of 27 injections were performed on 27 patients with sensorineural hearing loss. The lateral paracarotid out-of-plane and lateral in-plane approaches were identified as the easiest and safest methods among the four tested. In this report, we describe a new lateral paracarotid approach for ultrasound-guided SGB. An ipsilateral paratracheal short-axis transverse scan was acquired at the C6 level with a linear probe (6-13MHz). The probe was moved laterally, scanning the thyroid, carotid artery, internal jugular vein, longus colli muscle, and the transverse process of the C6, placing the carotid artery in the middle of the view. Light pressure was applied to the probe postero-medially to displace the carotid artery medially and completely compress the internal jugular vein. The needle was inserted out-of-plane between the lateral margin of the carotid artery and Chassaignac's tubercle, traversing the collapsed internal jugular vein, and targeted between the longus colli muscle and the prevertebral fascia. A total of 4ml of 0.2% ropivacaine was injected for each procedure after a negative aspiration test. Successful blockade was confirmed with the onset of Horner's sign. All 27 injections resulted in successful blockade with Horner's sign presenting within 5 min after injection. Side effects were minor and caused minimal discomfort; they included hoarseness and a foreign body sensation. No hematomas formed after any injections. We suggest that this new lateral paracarotid approach, with out-of plane needle insertion at the C6 tubercle under transverse scan, is a convenient and safe method for performing real-time ultrasound-guided SGB, as it provides a wide, safe space for needle passage without risking thyroid or esophageal injury.

Electric field induced nanoscale polarization switching and piezoresponse in Sm and Mn co-doped BiFeO3 multiferroic ceramics by using piezoresponse force microscopy

Samarium (5%Sm) and manganese (0.5%Mn) co-doped BiFeO3 (B5SF0.5MO) polycrystalline multiferroic ceramics were prepared by solid-state-reaction to study the morphology, local polarization switching and piezoresponse, using atomic force microscopy (AFM) and piezoresponse force microscopy (PFM). Room temperature x-ray diffraction (XRD) and micro-Raman spectra reveal that samarium and manganese co-doping retains the parental rhombohedral R3c structure of BiFeO3 (BFO). The out-of-plane (OP) PFM phase images show domains with oppositely oriented polarizations which are distinguished as domains with downward and upward polarizations with respect to the cantilever direction. Polarization switching occurs in the poled sample by locally poling the sample at negative and positive biases. Following the domain switching mechanism in BFO, it was found that 109° domain switching occurred besides the growth of 180° domains upon application of an electric field. The clockwise phase hysteresis implies the Debye model of piezoelectric relaxation effect due to defects that are both elastic and electric dipoles. The negative self-polarization in these samples is supposed to be the result of built-in internal bias field generated from excess electrons and charge defects like oxygen vacancies. The Saturated localized in-field hysteresis phase and amplitude loops from 180° domains suggest the existence of well-defined polarization along the field direction and suggests that Sm and Mn co-doped BFO can be a potential material for nanoscale piezoelectric applications.

Three-dimensional resistivity and switching between correlated electronic states in 1T-TaS2

Recent demonstrations of controlled switching between different ordered macroscopic states by impulsive electromagnetic perturbations in complex materials have opened some fundamental questions on the mechanisms responsible for such remarkable behavior. Here we experimentally address the question of whether two-dimensional (2D) Mott physics can be responsible for unusual switching between states of different electronic order in the layered dichalcogenide 1T-TaS2, or it is a result of subtle inter-layer “orbitronic” re-ordering of its stacking structure. We report on in-plane (IP) and out-of-plane (OP) resistance switching by current-pulse injection at low temperatures. Elucidating the controversial theoretical predictions, we also report on measurements of the anisotropy of the electrical resistivity below room temperature. From the T-dependence of ρ⊥ and ρ||, we surmise that the resistivity is more consistent with collective motion than single particle diffusive or band-like transport. The relaxation dynamics of the metastable state for both IP and OP electron transport are seemingly governed by the same mesoscopic quantum re-ordering process. We conclude that 1T-TaS2 shows resistance switching arising from an interplay of both IP and OP correlations.

Multi-Scale Finite Element Analyses of Thermal Conductivities of Three Dimensional Woven Composites

This paper summarizes an extensive experimental and prediction study of thermal conductivities of three-dimensional woven composites (3DWCs). Three kinds of innovative 3D woven architectures are examined, including 2.5D angle-interlock, 2.5D angle-interlock (with warp reinforcement), and 3D orthogonal woven architectures. The differences of thermal behaviors of 3DWCs in plane and out of plane are assessed by using multi-scale finite element analysis. For the validation of models, the thickness direction thermal conductivity of 3DWCs are measured. It is indicated that the predicted results are in good agreement with the experimental results. The effects of weave density and fabric architecture on the distribution of heat flux and temperature have been discussed in this work, which determined the thermal conductivities of 3DWCs. From this study, it can be expected that the need of thermal performance of 3DWCs can obtained according to optimize the weave parameters based on the high designability of 3DWCs.

Discrete and continuous models for static and modal analysis of out of plane loaded masonry

A critical review of analytical and numerical models for studying masonry out of plane behaviour is presented. One leaf historical masonry, composed by rigid blocks arranged regularly with dry or mortar joints, is considered. Discrete model with rigid blocks, Love-Kirchhoff and Reissner-Mindlin plate models and 3D heterogeneous FEM are adopted. An existing simple and effective discrete model is adopted and improved by applying matrix structural analysis techniques for static and modal analysis of masonry walls in the elastic field, but the formulation allows to account also for material nonlinearity. Elastic parameters of both plate models are based on an existing compatible identification between 3D discrete model and 2D plate models. Static and modal analysis of masonry walls with several boundary conditions are carried on, numerical tests account for in plane size of heterogeneity and structure thickness by means of in and out of plane scale factors. Results show that discrete model is simple and effective for representing masonry behaviour, especially when size of heterogeneity is smaller than overall panel size. Decreasing in plane scale factor, plate models converge to the discrete one, but the Reissner-Mindlin one shows a better convergence and also allows adopting a simple FE for performing numerical analysis.

The out of plane a.c. fluctuation conductivity of superconductor under magnetic field

The time-dependent Ginzburg-Landau model with thermal noise is used to calculate the out of plane a.c. fluctuation conductivity of type-II superconductor under magnetic field. We assume that thermal fluctuations, represented by the Langevin white noise, are strong enough to melt the Abrikosov vortex lattice created by the magnetic field into a moving vortex liquid. The nonlinear interaction term in the time-dependent Ginzburg-Landau equation is treated within the self-consistent Gaussian approximation. The real and imaginary parts of the out of plane a.c. fluctuation conductivity formula are summation over all Landau levels to treat arbitrary magnetic fields. Our results indicate that high frequencies can be effectively used to suppress the out-of-plane a.c. fluctuation conductivity in high-temperature superconductors. The results also have refined analytical form and are fitted well to experimental data on high-Tc superconductor. The results in two-dimensional and three-dimensional limits are directly inferred from the corresponding result of the layered model.

Fcc and bcc structured ferromagnetic films with five to twenty spin layers explained by second order perturbed Heisenberg Hamiltonian

Second order perturbed 2-D Heisenberg Hamiltonian model was employed to explain the magnetic properties of fcc and bcc structured ferromagnetic thin films with five to twenty spin layers. Magnetic energy versus azimuthal angle of spin was plotted to find the angle corresponding to maximum energy and minimum energy. Hence magnetic easy and hard directions were determined. The magnetic easy axis gradually rotates from out of plane (perpendicular) to in plane direction as the number of spin layers is increased. This implies that the films indicates a preferred in plane easy axis orientation at higher thicknesses. The energy required to rotate spin from hard to easy (or vice versa) directions gradually increases with number of spin layers. Our results agree with the experimental data obtained for ferromagnetic thin films.