Plane Parallel Research Articles

Removal of Incarcerated Screws with Damaged Heads using a Novel Technique of Creating Two Straight and Parallel Planes on the Screw Head with a High Speed Diamond-Tipped Burr and Stable Grip of a Locking Plier.

Removal of Incarcerated Screws with Damaged Heads using a Novel Technique of Creating Two Straight and Parallel Planes on the Screw Head with a High Speed Diamond-Tipped Burr and Stable Grip of a Locking Plier.

Laser powder bed fused Inconel 718 in stress-relieved and solution heat-treated conditions

Inconel 718 superalloy cylindrical rods were fabricated using the laser powder bed fusion (L-PBF) technology in the vertical orientation. The rods were stress-relieved at 980 °C for 15 min before cutting them from the build plate. The microstructure in this condition exhibited a significant amount of undesirable needle-like δ-phase precipitates and a small amount of interdendritic Laves phase that is finer in size. Differential Scanning Calorimetry (DSC) was used to determine the temperatures for solid-state phase transformations and appropriate temperature for solution-treatment. Solution-treatment was performed at 1065 °C for 1 h, followed by air cooling. The microstructures were characterized with specific reference to δ-phase and Nb segregation. Solution-treatment at 1065 °C was found to result in a significant elimination of micro-segregation (mainly Nb), complete dissolution of δ phase, considerable Laves dissolution, and partly undissolved carbide particles (few nm in size). Solution-treatment did not produce a significant change in the grain morphology (columnar dendritic) on a plane parallel to the build direction but more recrystallized and equiaxed grains were formed on a plane perpendicular to the build direction. The hardness of the solution-treated sample is comparable with wrought 718 alloys but lesser (115 HV) than in the stress-relieved condition attributing to the annihilation of dislocation tangles.

Numerical investigation on the flow characteristics of model dandelion seeds with angles of attitude

A stable and axisymmetric “separated vortex ring” formed above the pappus can greatly improve the aerodynamic efficiency of dandelion seeds and reduce the material requirement for flight. Since the dandelion seed is not always in a “regular” state (i.e., the pappus plane parallel to the horizontal plane) when flying, this paper uses a simplified rigid pappus model to simulate and analyze the influence of flight attitude on the flow patterns and the resulting changes in aerodynamic characteristics under different porosities. The numerical results are obtained by solving the three-dimensional incompressible steady RANS equations with the Spalart–Allmaras turbulence model in ANSYS Fluent software package. The results show that when there is an angle of attitude, the separated vortex ring will break with one of the vortices, losing its original recirculating structure, which leads to a considerable loss of the drag performance. In addition, the high-pressure region below the pappus plane shifting to one side will produce a horizontal force and a recovery moment against the rolling direction. The horizontal force component generated by a large-porosity pappus disk is much larger than that of a solid disk, which shows the good flight efficiency of dandelion seeds. At the same time, the inclined pappus will produce a recovery moment to keep the seed from rolling away from the horizontal plane. These conclusions show that the pappus structure has the potential to adjust the flight attitude and aerodynamic characteristics, which provides a preliminary understanding for further study on the flight dynamics of dandelion seeds.

Study of the Radiation Flux Distribution in a Parabolic Dish Concentrator

The radiation flux distributions produced by the concentrating solar systems used to produce thermal/electrical power are usually non-homogeneous. This results in non-uniform temperature distributions on the solar receivers, causing adverse effects on the system’s overall performance. An approach to better understand the problem is to study the surfaces around the focal zone where the radiation density is homogeneous (isosurfaces), generating them from experimental data. For this, it is necessary to superimpose built volumes of the different irradiance levels using parallel planes in different directions from the focal point of a concentrator. These volumes are known as effective volumes. This study presents the model used to generate effective volume produced by a point focus concentrator, comparing it with experimental results in a direction perpendicular to the focal axis. The effective volumes were developed considering a global optical error of the system of 2.8 mrad. The set of methods used to generate effective volumes has not been previously presented in the literature. The theoretical-experimental research consisted of the combination of the camera-target method and the simulations by the ray-tracing technique. The results showed effective volumes with the highest value of 10 MW/m2 and the lowest value of 4.5 MW/m2.

Efficacy of Using Perichondrioadipodermal Flap With Combined Techniques in Prominent Ear Correction.

Prominent ear is 1 of the most common congenital deformities of the ear. Incidence is reported as approximately 5%. This deformity can classically be the result of antihelix insufficiency, overprojection of concha or combination of both. Less frequently, folded or overprojectile ear lobule can aggravate the deformity. Surgical techniques can be aimed at concha, antihelix formation, lobule positioning. In our study, postoperative results for the combination of suture otoplasty and perichondrioadipodermal flap techniques in prominent ear surgery is discussed in light of the recent literature. Forty-nine patients that were operated for prominent ear deformity in our clinic between 2010 and 2015 were evaluated. Anatomic structures that cause the anomaly was analyzed by photographing concha-scaphoid angle, antithetical fold absence or presence, position of the ear lobule, conchal depth, size of the auricula, and positioning Frankfort Plane parallel to the ground. The patients were photographed preoperatively, at postoperative first week and postoperative sixth month, respectively. Comparison of age, surgical technique, surgical complications, necessity for revision surgery, additional procedures, follow up time, preoperative, and postoperative helix-mastoid bone distance were evaluated. Forty-nine patients have been evaluated. Thirty-one of these patients were female, whereas 18 were male. Age of these patients ranged between 6 and 37. Operations were performed in 47 right side ears, and 44 left side ears (97% bilateral and 7% unilateral otoplasty). Preoperative helix-mastoid bone distance ranged between 21 and 33 mm (mean 26.77), whereas postoperative helix-mastoid bone distance was measured between 12 and 22 mm (mean 16.26). Compared to the preoperative values, helix-mastoid distance difference was statistically significant (P < 0.05). Asymmetry and recurrence are the most common late complications of prominent ear surgeries. Perichondrioadipodermal flap can be safely added to the combined surgical techniques protecting the cartilage support, therefore, reducing complication rates, with satisfying results.

Position resolution with 25 µm pitch pixel sensors before and after irradiation

Pixelated silicon detectors are state-of-the-art technology to achieve precise tracking and vertexing at collider experiments, designed to accurately measure the hit position of incoming particles in high rate and radiation environments. The detector requirements become extremely demanding for operation at the High-Luminosity LHC, where up to 200 interactions will overlap in the same bunch crossing on top of the process of interest. Additionally, fluences up to 2.3 × 1016cm−2 1MeV neutron equivalent at 3.0cm distance from the beam are expected for an integrated luminosity of 3000fb−1. In the last decades, the pixel pitch has constantly been reduced to cope with the experiments’ needs of achieving higher position resolution and maintaining low pixel occupancy per channel. The spatial resolution improves with a decreased pixel size but it degrades with radiation damage. Therefore, prototype sensor modules for the upgrade of the experiments at the HL-LHC need to be tested after being irradiated. This paper describes position resolution measurements on planar prototype sensors with 100 × 25µm2 pixels for the CMS Phase-2 Upgrade. It reviews the dependence of the position resolution on the relative inclination angle between the incoming particle trajectory and the sensor, the charge threshold applied by the readout chip and the bias voltage. A precision setup with three parallel planes of sensors has been used to investigate the performance of sensors irradiated to fluences up to ϕeq=3.6×1015 cm−2. The measurements were performed with a 5GeV electron beam. A spatial resolution of 3.2±0.1µm is found for non-irradiated sensors, at the optimal angle for charge sharing. The resolution is 5.0±0.2µm for a proton-irradiated sensor at ϕeq=2.1×1015 cm−2 and a neutron-irradiated sensor at ϕeq=3.6×1015 cm−2. The extrapolated resolution to infinite beam momentum, where the contribution of multiple scattering can be neglected, has also been evaluated.

Precipitation of Stable Icosahedral Quasicrystal Phase in A Mg-Zn-Al Alloy

Precipitation of a stable quasicrystalline i-phase has been discovered in a Mg-6Zn-3Al (wt%, ZA63) magnesium alloy, possibly a first involving a stable i-phase. Dissolution of i-phase solidified at grain boundaries leads to precipitation in the Mg-matrix during cooling due to a solvus boundary observed by phase diagram calculation. Phase transformation, nucleation characteristics, morphology and interfaces with the matrix have been studied. Differential scanning calorimetry (DSC) and in-situ X-ray diffraction (XRD) showed dissolution and precipitation of i-phase during heating and cooling cycles, forming a hysteresis between about 250 and 325°C. The quasilattice parameter a R of i-phase was calculated to be 5.1704 A at room temperature, close to the c-parameter 5.1831A of the Mg-matrix. At dissolution/nucleation, the diffraction peaks of i-phase were sharper, (quasi)lattice constants a R and c Mg become equal to each other (5.225A) and the lattice strain in the matrix was minimized. Precipitation occurred with a fivefold plane parallel to a matrix pyramidal {0111} plane, which gave rise to two possible orientation relationships (OR): 5f||[0001] (OR3’) and 2f||[0001] (OR1). Presence of both ORs in the same precipitates generated icosahedral twinning. The precipitates were faceted sharply on fivefold, twofold and threefold planes which were on basal, prismatic and pyramidal planes of the Mg matrix. Results suggest the OR selection to be nucleation temperature dependent. Based on the crystallographic relationships, 3-dimensional tiling model of icosahedral lattice has been used to model lattice match with the matrix.

The large-scale monopole of the power spectrum in a Euclid-like survey: wide-angle effects, lensing, and the ‘finger of the observer’

ABSTRACT Radial redshift-space distortions due to peculiar velocities and other light-cone effects shape the maps we build of the Universe. We address the open question of their impact onto the monopole moment of the galaxy power spectrum, P0(k). Specifically, we use an upgraded numerical implementation of the liger method to generate 140 mock galaxy density fields for a full Euclid-like survey and we measure P0(k) in each of them utilizing a standard estimator. We compare the spectra obtained by turning on and off different effects. Our results show that wide-angle effects due to radial peculiar velocities generate excess power above the level expected within the plane–parallel approximation. They are detectable with a signal-to-noise ratio of 2.7 for $k\lt 0.02\, h$ Mpc−1. Weak-lensing magnification also produces additional power on large scales which, if the current favourite model for the luminosity function of Hα emitters turns out to be realistic, can only be detected with a signal-to-noise ratio of 1.3 at best. Finally, we demonstrate that measuring P0(k) in the standard of rest of the observer generates an additive component reflecting the kinematic dipole overdensity caused by the peculiar velocity. This component is characterized by a damped oscillatory pattern on large scales. We show that this ‘finger of the observer’ effect is detectable in some redshift bins and suggest that its measurement could possibly open new research directions in connection with the determination of the cosmological parameters, the properties of the galaxy population under study, and the dipole itself.

A parameterization of sub-grid topographical effects on solar radiation in the E3SM Land Model (version 1.0): implementation and evaluation over the Tibetan Plateau

Abstract. Topography exerts significant influences on the incoming solar radiation at the land surface. A few stand-alone regional and global atmospheric models have included parameterizations for sub-grid topographic effects on solar radiation. However, nearly all Earth system models (ESMs) that participated in the Coupled Model Intercomparison Project (CMIP6) use a plane-parallel (PP) radiative transfer scheme that assumes that the terrain is flat. In this study, we incorporated a well-validated sub-grid topographic (TOP) parameterization in the Energy Exascale Earth System Model (E3SM) Land Model (ELM) version 1.0 to quantify the effects of sub-grid topography on solar radiation flux, including the shadow effects and multi-scattering between adjacent terrain. We studied the role of sub-grid topography by performing ELM simulations with the PP and TOP schemes over the Tibetan Plateau (TP). Additional ELM simulations were performed at multiple spatial resolutions to investigate the role of spatial scale on sub-grid topographic effects on solar radiation. The Moderate Resolution Imaging Spectroradiometer (MODIS) data was used to compare with the ELM simulations. The results show that topography has non-negligible effects on surface energy budget, snow cover, snow depth, and surface temperature over the TP. The absolute differences in surface energy fluxes for net solar radiation, latent heat flux, and sensible heat flux between TOP and PP exceed 20, 10, and 5 W m−2, respectively. The differences in land surface albedo, snow cover fraction, snow depth, and surface temperature between TOP and PP exceed 0.1, 0.1, 10 cm, and 1 K, respectively. The magnitude of the sub-grid topographic effects is dependent on seasons and elevations and is also sensitive to the spatial scales. Although the sub-grid topographic effects on solar radiation are larger with more spatial details at finer spatial scales, they cannot be simply neglected at coarse spatial scales. When compared to MODIS data, incorporating the sub-grid topographic effects overall reduces the biases of ELM in simulating surface energy balance, snow cover, and surface temperature, especially in the high-elevation and snow-covered regions over the TP. The inclusion of sub-grid topographic effects on solar radiation parameterization in ELM will contribute to advancing our understanding of the role of the surface topography on terrestrial processes over complex terrain.

Highly Stable Thin Films Based on Novel Hybrid 1D (PRSH)PbX3 Pseudo-Perovskites.

In this study, the structure and morphology, as well as time, ultraviolet radiation, and humidity stability of thin films based on newly developed 1D (PRSH)PbX3 (X = Br, I) pseudo-perovskite materials, containing 1D chains of face-sharing haloplumbate octahedra, are investigated. All films are strongly crystalline already at room temperature, and annealing does not promote further crystallization or film reorganization. The film microstructure is found to be strongly influenced by the anion type and, to a lesser extent, by the DMF/DMSO solvent volume ratio used during film deposition by spin-coating. Comparison of specular X-ray diffraction and complementary grazing incidence X-ray diffraction analysis indicates that the use of DMF/DMSO mixed solvents promotes the strengthening of a dominant 100 or 210 texturing, as compared the case of pure DMF, and that the haloplumbate chains always lie in a plane parallel to the substrate. Under specific DMF/DMSO solvent volume ratios, the prepared films are found to be highly stable in time (up to seven months under fluxing N2 and in the dark) and to highly moist conditions (up to 25 days at 78% relative humidity). Furthermore, for representative (PRSH)PbX3 films, resistance against ultraviolet exposure (λ = 380 nm) is investigated, showing complete stability after irradiation for up to 15 h at a power density of 600 mW/cm2. These results make such thin films interesting for highly stable perovskite-based (opto)electronic devices.

Online approach to measuring relative location of spatial geometric features of long rotating parts

Online relative location measurement of spatial geometric features is necessary for the high-precision manufacturing of long rotating parts. However, existing methods are imperfect because they are limited by the rotation state of the measured object or the measurement allowable space. To solve these problems, this study proposes a robust online measurement approach based on angle and size transfer, size transfer and analytical geometry theories. A polyhedral prism is used to synchronously calibrate the zero position of the laser displacement sensor, then a geometric model of the rotation angle corresponding to the sensor displacement change is established. Using only the displacement data, the 3-D relative location of multiple geometric features on different parallel planes is deduced by analytical geometry theory. The phase angle measurement of a diesel engine camshaft was used to verify the method. The results show that the method has high measurement precision, good stability and high efficiency.

Experimental research of nine parallel plane jets in non-blocking and blocking conditions

In the nuclear industry, blockage in the coolant passage of the plate-type fuel assembly may cause a serious accident to the reactor core. In this research, the 2D Particle Image Velocimetry (PIV) was applied to investigate the nine parallel plane jets in non-blocking and blocking conditions. Velocity fields of different planes in the jets in both conditions were obtained, and the overall trend of the multiple jets was figured out. Combining the flow field and the turbulence statistics, it could be seen that the two vortices caused by the blockage in the blocking conditions spreaded around and further downstream. The Power Spectral Density (PSD) analysis presented the characteristic frequency which also revealed the frequency evolution along the streamwise was in a particular pattern.

Bifurcations of a plane parallel flow with Kolmogorov forcing

We study the primary bifurcations of a plane parallel flow in a channel with Kolmogorov forcing. We find a new type of bifurcation with both the oscillation frequency and the amplitude of the growing mode being zero at the threshold. We call this a stationary drift bifurcation. The laminar steady flow can display different types of bifurcation depending on the forcing wave number of the base flow. This is in contrast to the case of doubly periodic boundary conditions for which the primary bifurcation is stationary.

Fluorescence method for kanamycin detection based on the conversion of G-triplex and G-quadruplex.

A versatile fluorescence scaffold was constructed by connecting a G-triplex sequence (G31) with G-rich DNA (aptamer of kanamycin) and using thioflavin T (ThT) as the fluorescent molecule. With the assistance of an aptamer, the G-quadruplex DNA structure was fabricated using G31 as three strands and the aptamer as the fourth strand. Due to the parallel planar morphology of the final products, which was favorable for ThT binding and which restricted the rotation of the aromatic rings of ThT, the fluorescence signal intensity of ThT was significantly enhanced. Because of the specific interaction of aptamer and kanamycin, in addition to the greater ability for kanamycin to bind with G-triplex than ThT, the conformation of G-quadruplex DNA was changed; in addition, ThT was dissociated from the aptamer-G31, and therefore a 'turn-on' to 'turn-off' detection principle was applied for kanamycin detection, which yielded reasonable sensitivity and selectivity. The detection range was 50-2000 nM, with a limit of detection of 1.05 nM. Our proposed method was thus successfully applied for kanamycin determination in pork, chicken, and beef samples, and satisfactory results were obtained.

Instability of the plane parallel flow through a saturated porous medium in the presence of a longitudinal magnetic field using the Chebyshev collocation method

The onset of instability against small disturbances of the pressure driven laminar fluid flow through a saturated porous medium in the presence of horizontal magnetic field between the two parallel impermeable plates is studied numerically. Assuming the channel walls have zero conductivity. The Chebyshev collocation method is used to solve the 6th order generalized Orr–Sommerfeld equation. The critical values of the Reynolds number Rec, the wave number αc and the wave speed cc are computed for various sets of the values of the porous parameter σp, magnetic Reynolds number Rm and Alfven number A. The marginal stability curves are drawn for various values of the physical parameters present in the problem. The onset of instability is also discussed in detail using the curves of growth rate of the disturbances and the critical values for various parameters present in the problem. It is observed that the role of σp, Rm and A are to delay the onset of instability of the system. The degree of stabilization is moderate up to certain value of A but it is so rapid when the Alfven number exceeds that value is observed. It is also seen that, the role of the combined influence of porosity of the porous medium and the strength of the magnetic field together suppress the growth of the disturbances very significantly. In this study the results computed are also compared with the existing literature as a particular case for ordinary Newtonian fluids.

Naphthalene-Pillared Benzene Triimide Cage: An Efficient Receptor for Polyhedral Anions and a General Tool for Probing Theoretically-Existing Anion-π Binding Motifs

A triangular prism cage 2 with benzene triimide (BTI) as the base and 2,7-naphthalene dimethylene as the supporting pillars was designed and synthesized efficiently. The two parallel BTI planes con...

Holographic lenses for the spatial patterning of particles toward tissue engineering in vivo

For tissue engineering, cells are aligned along defined structures that allow for cellular agglomeration and regeneration. Acoustic radiation force has been used for the contactless generation of patterns. Particles that are much smaller than the wavelength are agglomerated along high pressure regions and the forces are predicted using Gor’kov potential. Ultrasound standing waves have been used in vitro to create parallel planes where the cells agglomerate allowing for vascular tissue growth between planes. Here, we design and build a single-sided source with a holographic lens made using Fourier spectrum approach to generate parallel lines of high pressure amplitude over a limited range, few wavelengths, for cellular patterning. A few sources were fabricated at 1.5 and 2 MHz using geometrical and holographic lenses. The phase generation from holographic lenses was improved using global phase unwrapping scheme. Acoustic holography measurement was performed for all sources to verify the pressure output. The cellular patterning was tested on polyethylene microspheres (75-90 μm in diameter) that were placed in a cuvette with water and exposed to ultrasound. The microspheres were aligned along the high pressure region as predicted. This work has the potential to use single-sided transducers for cellular patterning toward tissue engineering in vivo.

Kinetics of grain-boundary nucleated transformations in rectangular geometries and one paradox relating to Cahn's model

It was found by Jägle and Mittenmeijer [Acta Mater. 59 (2011) 5775-5786] as a result of computer simulation that Cahn's equation underestimates pronouncedly the transformed fraction in reality. To test the hypothesis that a strong correlation in the arrangement of grains in the Cahn model (they are “tied” to planes) can be responsible for this phenomenon, the paradox of packing is described: the structures composed of the same elements (random parallelepipeds) transforming in the same way, but packed differently, give different transformation rates. One of these structures is a special Cahn model – the grain structure of parallelepipeds formed by three sets of random parallel planes orthogonal to each other. An alternative structure consists of the same parallelepipeds, but randomly packed; it looks like a real grain structure. It is shown analytically that the kinetics of transformation in the first structure is considerably slowed down in comparison with that in the second. For the various intermediate structures under consideration, the kinetic curves are between these two, so that the following rule is established: the transformation kinetics is accelerated, when the correlation in the arrangement of the parallelepipeds weakens. Preliminarily, volume-fraction expressions are obtained for the systems of an infinite number of parallel planes arranged both regularly and randomly. As a special case of random arrangement, a non-Poissonian point process (the second-order Erlang process) of the arrangement of planes is considered for the first time. The exact volume-fraction expression obtained for this case shows that it cannot be derived by Cahn's method, i.e. the extended-volume approach is applicable only to Poisson processes. The volume fraction equations for regular planes are used to study cubic grain structures, both regular and random. It is shown that Cahn's equation underestimates the transformation kinetics in both regular and random structures with four different size distributions of cubes; the degree of underestimation depends on the size distribution, being the largest in the regular structure.

Blade pitch and air-outlet width effects on the airflow generated by an airblast sprayer with wireless remote-controlled axial fan

The airblast sprayers are equipped with a fan generating an air stream that helps the sprayed droplets to reach out and penetrate the tree canopy. Recently an automatic air regulation system has been developed and integrated in an airblast sprayer equipped with a conventional axial fan (900 mm diameter). This system, thanks to a wireless connection between a dedicated tablet and sprayers actuators, allows to remotely control the blade pitch and the air-outlet section, varying the characteristics of airflow generated by the fan. Therefore, the present work aims to characterize the different air streams derived from the combination of two fan outlet section widths (110 and 150 mm) and three blade pitches (20°, 25° and 30°). For each combination, the three components of air velocity (m s−1) were measured, taking as reference the plane following the theoretical trajectory of the main current leaving the fan. In this plane, velocities were measured at 1.0, 3.0, 5.0 and 10.0 m from the outlet section on both sides of the sprayer. At each distance, the velocities from 0.25 to 4.00 m in height were recorded. This same procedure was repeated in two planes parallel to the reference plane, 0.30 m behind and after respectively. Additionally, the velocities in the fan outlet section were also measured to obtain the airflow rate. In general, the outlet section and the blade pitch had a significant effect on the velocity components. An outlet section of 110 mm meant a smaller airflow rate and a higher initial velocity, while with 150 mm the airflow rate reduced and the initial velocity decreased. Velocities could be bigger by enhancing the blade pitch. The turbulence intensity was similar at 1.0 m distance in all cases.

Shear stress relaxation through the motion of edge dislocations in Cu and Cu–Ni solid solution: A molecular dynamics and discrete dislocation study

Shear stress relaxation through the motion of multiple edge dislocations in a periodic cell is studied by molecular dynamics and discrete dislocation methods. In both methods, we consider systems with an initial edge dislocation on the parallel slip planes. The initial shear strain is applied to the system along the Burgers vector of the dislocations. The velocity profile for a single edge dislocation fitted from a molecular dynamics (Bryukhanov, 2020) is used as the input to discrete dislocation dynamics. The dependence of shear stress, plastic strain, and plastic strain rate on time are analyzed. We show that when dislocations are sufficiently far from each other, relaxation occurs due to dislocation motion, and dislocation velocity can exceed the anisotropic speed of sound. If the dislocations are closer together, relaxation is due to the growth of stacking faults. We find that the stress at which the stress relaxation mechanism changes decreases with increasing dislocation density. Stress relaxation in a Cu–Ni solid solution occurs faster than in pure Cu due to a higher dislocation velocity in the high-velocity regime. However, the shear stress at which nickel atoms increase the plastic strain rate increases with an increase in dislocation density. The dependence of the relaxation time on the dislocation density obtained in discrete dislocation simulations is approximated using the power law. The elastic interaction between dislocations reduces the exponent of the power law from 1/ρ to approximately 1/ρ0.8 for both pure Cu and Cu–Ni solid solutions.