Change In Penetration Depth Research Articles

London penetration depth of electron-irradiated Ba[formula omitted]K[formula omitted]Fe[formula omitted]As[formula omitted

We have characterized an electron-irradiated Ba0.47K0.53Fe2As2 single-crystal using two different techniques: magneto-optic and microwave measurements. The crystal has been measured before as well as after the 2.5 MeV electron irradiation process. After irradiation it was annealed in a number of steps, between 90 °C and 180 °C. At each step, we employ a resonant microwave cavity technique to determine the London penetration depth changes δλab and δλc of the sample. Equations based on perturbation theory were derived to calculate δλab and δλc for a rectangular prism geometry. A procedure to correct the magneto-optic measurements was introduced. We have demonstrated that the superconducting properties of Ba0.47K0.53Fe2As2, degraded by intense electron beam irradiation, can be restored by a simple annealing procedure and the corresponding Uemura plot is in the vicinity of data for hole-doped copper oxides.

Deformation Retrievals for North America and Eurasia from Sentinel-1 DInSAR: Big Data Approach, Processing Methodology and Challenges

A fully automated processing system for measuring long-term ground deformation time series and deformation rates frame-by-frame using DInSAR processing technique was developed at the Canada Center for Remote Sensing. Ground deformation rates from 2017 to 2023 were computed over a large territory of North America and Eurasia from more than 220,000 readily available Sentinel-1 images, and the performance and shortcomings of the developed processing system were analyzed. Here, we present the processing methodology and several examples of deformation rate maps and time series produced with this automated system. Examples include the deformation of slow- moving deep-seated landslides in two regions of Canada, subsidence at the Komsomolskoe oil field in the Russian Arctic, the Tengiz oil field in Kazakhstan, multiple large subsiding regions and landslides in northwestern Iran, and two large subsiding regions in the Yellow River Delta and Xinjiang, China. Many deformation processes observed in these deformation rate maps, including large landslides, have previously been unknown to the research community. Systematic radar penetration depth changes were observed in multiple regions and were investigate in detail for 1 Eurasian region. Computed deformation rates for North America and Eurasia are available to the research community and can be downloaded from the data repository.

Analysis Method of X-Ray Diffraction Characteristic Values and Measured Strain for Steep Stress Gradient of Metal Material Surface Layer

The most comprehensive and particularly reliable method for non-destructively measuring the residual stress of the surface layer of metals is the sin2ψ method. When X-rays were used the relationship of εϕψ-sin2ψ measured on the surface layer of the processing metal did not show linearity when the sin2ψ method was used. In this case, since the effective penetration depth changes according to the changing direction of the incident X-ray, σϕ becomes a sin2ψ function. Since σϕ cannot be used as a constant, the relationship in εϕψ-sin2ψ cannot be linear. Therefore, in this paper, the orthogonal function method according to Warren’s diffraction theory and the basic profile of normal distribution were synthesized, and the X-ray diffraction profile was calculated and reviewed when there was a linear strain (stress) gradient on the surface. When there is a strain gradient, the X-ray diffraction profile becomes asymmetric, and as a result, the peak position, the position of half-maximum, and the centroid position show different values. The difference between the peak position and the centroid position appeared more clearly as the strain (stress) gradient became larger, and the basic profile width was smaller. The weighted average strain enables stress analysis when there is a strain (stress) gradient, based on the strain value corresponding to the centroid position of the diffracted X-rays. At the 1/5 Imax height of X-ray diffraction, the position where the diffracted X-ray is divided into two by drawing a straight line parallel to the background, corresponds approximately to the centroid position.

Nodeless superconductivity in the topological nodal-line semimetal CaSb2

CaSb2 is a topological nodal-line semimetal that becomes superconducting below 1.6 K, providing an ideal platform to investigate the interplay between topologically nontrivial electronic bands and superconductivity. In this work, we investigated the superconducting order parameter of CaSb2 by measuring its magnetic penetration depth change {\Delta}{\lambda}(T) down to 0.07 K, using a tunneling diode oscillator (TDO) based technique. Well inside the superconducting state, {\Delta}{\lambda}(T) shows an exponential activated behavior, and provides direct evidence for a nodeless superconducting gap. By analyzing the temperature dependence of the superfluid density and the electronic specific heat, we find both can be consistently described by a two-gap s-wave model, in line with the presence of multiple Fermi surfaces associated with distinct Sb sites in this compound. These results demonstrate fully-gapped superconductivity in CaSb2 and constrain the allowed pairing symmetry.

Numerical and Experimental Study on Jet Trajectory and Fuel Concentration Distribution Characteristics of Kerosene Jet in Air Crossflow

The fuel concentration distribution in an afterburner is a critical factor that affects its ignition, flameout, stability, and combustion efficiency. Additionally, the trajectory of the fuel jet directly affects the distribution of the downstream fuel. Hence, this paper studied the factors that affect a jet’s trajectory and fuel concentration distribution through numerical calculations. The change law of the fuel jet trajectory under various parameters was studied, and the jet penetration depth change rate was analyzed. Moreover, the empirical formula of the spanwise distribution range of the liquid fuel in front of the stabilizer was fitted. Furthermore, this study investigated fuel concentration distribution experimentally in the afterburner under normal temperature and pressure. The paper obtained the variation law of fuel concentration in the spanwise and radial directions, and the proportion of the gaseous fuel in the flow section under the influence of different parameters. Additionally, the spatial distribution of the droplet concentration was obtained, revealing that it increased initially, and then decreased in the flow direction, reaching a peak at the end of the recirculation zone. In the radial direction, two concentration peaks were found in the boundary of the recirculation zone and in the main flow region.

Nodeless superconductivity in topologically nontrivial materials HfRuP and ZrRuAs

Topologically nontrivial electronic states are recently found in a family of noncentrosymmetric transition metal pnictides TRuX ( Zr, Hf; P, As), presenting a unique platform for superconductivity to interplay with topological electronic states and asymmetric spin–orbit coupling. Here, we investigate the superconducting order parameter of HfRuP and ZrRuAs by measuring the magnetic penetration depth change using a method based on the tunnel-diode oscillator. Both compounds show clear exponential temperature dependence in at low temperatures, suggesting fully-gapped superconductivity. Moreover, the superfluid densities in both HfRuP and ZrRuAs can be reasonably described by an s-wave superconducting model.

Improvement of technology for repair of ore-bucket unloader metal structure working under cyclic loading

ABSTRACT The basis of all machines and mechanisms of cranes is a metal structure, more often welded; therefore, the further operation of the machine is influenced by reliability and safety of operation of a metal structure. With the operation of such unique equipment as ore-grab loaders, the problem of ensuring trouble-free operation is becoming more acute and relevant every year. There are methods that increase the current density of the arc by compressing it during plasma welding, cutting, as well as injected into the coating of the electrodes of substances with high affinity for the electron. However, at repair welding, manual welding by an artificial electrode is most often applied. The research work was conducted on modernisation of the power supply to increase the depth of penetration during welding. The studies of changes in penetration depth on the same technological modes for a typical and upgraded power supply were performed. It was found that the penetration depth increases by more than 30% as a result of the final welding stresses, deformations, the risk of fatigue cracks decreases. After repairs with an upgraded power supply, there are no stress concentrators, reduced thermal impact zone and, as a result, reduced final welding stresses.

Fall cone behavior of non-plastic silts and undrained shear strength from DSS tests

Fall cone penetration behaviour of clays had been investigated for years, however, very little is known about the fall cone penetration behaviour of silts, especially low to non-plastic ones. Extensive fall cone tests were done on three different non-plastic silts over a broad penetration range. The results were compared with the behaviour of various soils with low and high plasticity. It was observed that the fall cone penetration water content relationship is typically non-linear for most plastic soils. However, it surprisingly becomes linear at the extreme sides of plasticity. More explicitly, the change of penetration depth with water content of non-plastic silts and bentonites are shown to be expressed with the same linear equation with different coefficients. Next, undrained shear strengths of silts were determined from direct simple shear tests performed under at least three vertical consolidation stresses. The simple power relationship between water content and undrained shear strength, proposed for remoulded clays in the literature, is observed to work very well for reconstituted non-plastic silts as well. Finally, undrained shear strengths of silts were predicted based on their liquid limits obtained from fall cone tests by modifying a relationship in the literature, which was developed mainly on clays.

Identifying 3-D spatiotemporal skin deformation cues evoked in interacting with compliant elastic surfaces.

We regularly touch soft, compliant fruits and tissues. To help us discriminate them, we rely upon cues embedded in spatial and temporal deformation of finger pad skin. However, we do not yet understand, in touching objects of various compliance, how such patterns evolve over time, and drive perception. Using a 3-D stereo imaging technique in passive touch, we develop metrics for quantifying skin deformation, across compliance, displacement, and time. The metrics map 2-D estimates of terminal contact area to 3-D metrics that represent spatial and temporal changes in penetration depth, surface curvature, and force. To do this, clouds of thousands of 3-D points are reduced in dimensionality into stacks of ellipses, to be more readily comparable between participants and trials. To evaluate the robustness of the derived 3-D metrics, human subjects experiments are performed with stimulus pairs varying in compliance and discriminability. The results indicate that metrics such as penetration depth and surface curvature can distinguish compliances earlier, at less displacement. Observed also are distinct modes of skin deformation, for contact with stiffer objects, versus softer objects that approach the skin's compliance. These observations of the skin's deformation may guide the design and control of haptic actuation.

In-situ measurement of weld quality during MAG welding using laser ultrasonic

ABSTRACT Laser ultrasonic technique (LUT) is applicable for measurement under high temperature condition because of the non-contact and remoteness. In this study, LUT was applied to detection the welding defect such as solidification crack and/or lack of penetration at single bevel groove during Gas Metal Arc (GMA) welding process. Nanosecond pulse laser (1064 nm, 60 mJ/pulse 100 Hz) was used to generate ultrasonic, and was scanned using a galvanometer mirror. Nd:YAG laser interferometer (532 nm, 1 W) was used for detection the surface micro vibration caused by arrival of ultrasonic wave. After acquiring the B-scope, which is composed of multi transmit- and receive-points, the synthetic aperture focusing technique (SAFT) is applied. SAFT image obtained by in-process measurement was evaluated to confirm the presence or absence of welding defect indication. As a result, it was possible to indicate the solidification crack and the lack of penetration in the joint even during the welding process. Furthermore, it was able to indicate the penetration depth change (2 mm difference) due to the welding condition change during process. These results suggest that in-process measurement using LUT is very effective technique for detecting weld defects.

Effects of space charge on weld geometry and cooling rate during electron beam welding of stainless steel

Although heat input rate is universally accepted as a scale-up criterion for weld-geometry, especially for arc/laser welding, its position in electron beam welding (EBW) needs a relook. Our experiments reveal that heat input per unit length cannot always be taken as a parameter indeed to determine weld-geometry accurately. The electron-repulsion-induced space charge effect (SCE), especially during EBW carried out under vacuum, has been attributed for such phenomenon. The change in depth of penetration, bead width, volume of material melted, cooling rate and grain boundary character distribution (GBCD) have been studied as the function of input process parameters. Moreover, a finite element analysis has been carried out to account for this SCE in terms of effective beam spread. Here, some preferences and ranges of these parameters are suggested to suppress SCE, and thereby, obtaining the higher depth of penetration and low bead-width. These desired weld-geometries are observed with high welding speed, and beam current to accelerating voltage ratio (I/V) lying in a range of (0.9, 2.0).

An Iterating Method to Calculate the Geometry of Range Modulation Wheel in Passive Proton Therapy

In the passive method of proton therapy, range modulation wheel is used to scatter the single energy proton beam. It rounds and scatters the single energy proton beam to the spectrum of particles that covers cancerous tissue by a change in penetration depth. Geant4 is a Monte Carlo simulation platform for studying particles behaviour in a matter. We simulated proton therapy nozzle with Geant4. Geometric properties of this nozzle have some effects on this beam absorption plot. Concerning the relation between penetration depth and proton particle energy, we have designed a range modulation wheel to have an approximately flat plot of absorption energy. An iterative algorithm programming helped us to calculate the weight and thickness of each sector of range modulation wheel. Flatness and practical range are calculated for resulting spread-out Bragg peak.

Influence factors of pop-in in the nanoindentation micromechanical property measurement of gas-bearing shale

Abstract Studying the micromechanical properties of gas-bearing shale is very important for understanding it. In the nanoindentation measurement of gas-bearing shale, the load-displacement curve often shows pop-in at the loading stage, namely the change of load is small but the change of penetration depth is large. Pop-in can introduce a large error in the calculation of the mechanical parameter. To investigate the influence factors of pop-in, the maximum load, load rate and sample characteristics have been addressed. The results show that pop-in is related to cracks and pores in the shale. Due to the heterogeneity of shale, pop-in cannot be avoided, but can be reduced by choosing reliable load modes and test parameters. Pop-in can increase the maximum indentation depth and decrease the elastic modulus and hardness. The influence of pop-in on hardness is larger than on the elastic modulus. At a high load rate it is easy to induce pop-in. The influence of the load rate on pop-in is larger than that of the maximum load.

Modeling of Superconducting Passive Transmission Lines

Superconducting technologies are moving toward very large-scale integration (VLSI) of circuits. Passive transmission lines (PTLs) are used to quickly and efficiently propagate single flux quantum pulses between separated logic elements of these VLSI circuits. PTLs are often insufficiently modeled to correspond to reality. Therefore, the PTL needs to be thoroughly studied to determine realistic propagation characteristics. A quasi-transverse magnetic (TM) formulation is used to study superconducting passive transmission lines. The ambient temperature and changes in penetration depth with frequency are taken into account when solving the electromagnetic fields of a PTL. Per-frequency transmission line parameters are extracted from the quasi-TM field solutions. The results show a very close correlation to TetraHenry, an existing 3D solver, at significantly reduced computational cost. The results also clearly show that PTL propagation characteristics are sensitive to frequency and temperature.

Time and space resolved current density mapping in three dimensions using magnetic field probe array in a high voltage coaxial gap

We present an experimental analysis of the symmetry of current density in a coaxial geometry, diagnosed using a magnetic field probe array and calculations of the Fowler-Nordheim enhancement factor. Data were collected on the coaxial gap breakdown device (240 A, 25 kV, 150 ns, ∼0.1 Hz), and data from experiments using 2 different gap sizes and different penetration depths are compared over runs comprising 50 shots for each case. The magnetic field probe array quantifies the distribution of current density at three axial locations, on either sides of a vacuum breakdown, and tracks the evolution with time and space. The results show asymmetries in current density, which can be influenced by changes in the gap size and the penetration depth (of the center electrode into the outer electrode). For smaller gap sizes (400 μm), symmetric current profiles were not observed, and the change in the penetration depth changes both the symmetric behavior of the current density and the enhancement factor. For larger gaps (900 μm), current densities were typically more uniform and less influenced by the penetration depth, which is reflected in the enhancement factor values. It is possible that the change in inductance caused by the localization of current densities plays a role in the observed behavior.

Investigation of optical sensor approaches for real-time monitoring during fibre laser welding

Laser beam welding can be a high productivity joining process, offering significant benefits over conventional welding methods. However, the need for real-time monitoring of laser welding processes is important to provide information on the possible presence of imperfections formed during welding and guarantee quality assurance in production. Laser process monitoring methods are based on the recording of physical phenomena occurring during the laser-material interaction. This paper has investigated an established optical-based monitoring method, using photodiodes responsive to either visible or near-infrared emissions, to correlate the photodiode signals with different types of weld features, imperfections and/or process anomalies. These have included occurrence of internal porosity, changes in penetration depth and beam to joint alignment, deliberate changes in laser power and intentionally poor joint preparation, cleanliness or fit-up. Also, a new type of commercially available process monitoring approach was investigated, based on laser interferometry, to measure keyhole depth. The results of both approaches have confirmed which types of weld features, imperfections and/or process anomalies are most sensitive to these monitoring techniques, with potential to then implement these findings in to a future multisensor solution for real-time process control.

Finite element analysis of residual stress evolution with multiple impacts on one point in ultrasonic impact treatment process

The ultrasonic impact treatment process is widely used to improve the fatigue life of the weldments by inducing compressive residual stresses at the sub-surface. The purpose of the article is to conduct the dynamic elastic–plastic finite element analysis of multiple impacts on 5A06 aluminum alloy with different controlled parameters. The numerical model was validated by pin drop test. The changes in penetration depth, maximum compressive residual stress, and surface residual stress were obtained by analyzing the residual stress field and equivalent plastic strain. The effect of impact times, impact velocities, pin shapes, and impact angles on the residual stress was investigated so that the ultrasonic impact treatment parameters could be controlled to obtain expected residual stress distributions.

Ultrafast pump-probe ellipsometry setup for the measurement of transient optical properties during laser ablation.

Ultrashort pulsed lasers offer a high potential in precise and efficient material processing and deep understanding of the fundamental laser-material interaction aspects is of great importance. The transient pulse reflectivity in conjunction with the transient absorption influences decisively the laser-material interaction. Direct measurements of the absorption properties by ultrafast time-resolved ellipsometry are missing to date. In this work, a unique pump-probe ellipsometry microscope is presented allowing the determination of the transient complex refractive index with a sub-ps temporal resolution. Measurements on molybdenum show ultrafast optical penetration depth changes of -6% to + 77% already within the first 10ps after the laser pulse impact. This indicates a significant absorption variation of the pump pulse or subsequent pulses irradiating the sample on this timescale and paves the road towards a better understanding of pulse duration dependent laser ablation efficiency, double or burst mode laser ablation and lattice modifications in the first ps after the laser pulse impact.

Analysis of reflectance curve of turbid media and determination of the non-surface complex refractive index

Based on the theory of Goos-Hänchen shift and its continuity near the critical angle, we introduce the concept of penetration depth below the critical angle, and obtain the general formula of reflectance using the gradient complex refractive index multilayered model. Compared with the fitting curve with Fresnel's Formula, our calculated results are more consistent with experimental results of Intralipid solution and the suspension of rutile TiO(2) powder. Combining the change of penetration depth near the critical angle with our model, we also reveal the essence of a simple method used to obtain the non-surface complex refractive index of turbid media.

석면 함유 천장재의 안정화제 희석에 따른 침투깊이 연구

Objectives: This study is designed to analyze the penetration performance into ceiling materials containing asbestos of scattering prevention agents and investigate the change in penetration depth and viscosity according to the dilution rate of anti-scattering agents diluted with distilled water. Methods: Five different types of scattering prevention agents were spread on plate-type asbestos ceiling materials. The penetration depth of each coated ceiling material was measured by energy dispersive spectroscopy (EDS) analysis, based on X-ray fluorescence (XRF) results of the non-coated ceiling materials. Test equipment installed the ceiling materials and 60 minutes were collected at a flow rate of <TEX>$10{\ell}/min$</TEX> at a filter of 25 mm. Results: An EDS analysis of the cross-section of ceiling materials constructed with a scattering prevention agent revealed that potassium is detected in the process of penetrating hardener solidification and this element could be an indicator for infiltration. When anti-scattering agents with different viscosities were constructed and the penetration depth was analyzed by potassium detection assessment using EDS, the depth results with viscosities of 5.0, 2.5, and 1.9 cP were 98.5, 103, and <TEX>$147{\mu}m$</TEX>, respectively. Penetration performance improved with decrease in viscosity. Conclusions: For asbestos ceiling materials, it is concluded that a higher dilution rate of the scattering prevention agent leads to lower viscosity, and hence a deeper penetration depth from <TEX>$156{\mu}m$</TEX> to 3 mm. The asbestos anti-scattering properties according to the penetration depth will be confirmed through further study.