Radial Process Research Articles

Stagnation of Saturn's auroral emission at noon

AbstractAuroral emissions serve as a powerful tool to investigate the magnetospheric processes at Saturn. Solar wind and internally driven processes largely control Saturn's auroral morphology. The main auroral emission at Saturn is suggested to be connected with the magnetosphere‐solar wind interaction, through the flow shear related to rotational dynamics. Dawn auroral enhancements are associated with intense field‐aligned currents generated by hot tenuous plasma carried toward the planet in fast moving flux tubes as they return from tail reconnection site to the dayside. In this work we demonstrate, based on Cassini auroral observations, that the main auroral emission at Saturn, as it rotates from midnight to dusk via noon, occasionally stagnates near noon over a couple of hours. In half of the sequences examined, the auroral emission is blocked close to noon, while in three out of four cases, the blockage of the auroral emission is accompanied with signatures of dayside reconnection. We discuss some possible interpretations of the auroral “blockage” near noon. According to the first one, it could be related to local time variations of the flow shear close to noon. Auroral local time variations are also suggested to be initiated by radial transport process. Alternatively, the auroral blockage at noon could be associated with a plasma circulation theory, according to which tenuously populated closed flux tubes as they return from the nightside to the morning sector experience a blockage in the equatorial plane and they cannot rotate beyond noon.

The radial approach to the wrist with styloidectomy: A cadaver study

The radial approach to the wrist is already used in several surgical techniques such as radial styloidectomy and Zaidemberg's vascularized radial graft. The aim of our work was to describe the surgical anatomy of that approach and to determine the acceptable limits of radial oblique styloidectomy that does not damage the anterior and posterior radiocarpal ligaments. This radial approach was performed on 11 cadaver specimens. The superficial branches of the radial nerve and the antebrachial cephalic vein were carefully located in the superficial plane. The radiocarpal articular capsule was opened longitudinally between the first and second compartments of the extensor tendons. We drew the oblique radial styloidectomy line at 3, 6 and 9mm from the apex of radial styloid process on the articular surface and then measured the width of ligaments theoretically taken away by the styloidectomy. An oblique radial styloidectomy of less than 6mm preserved the anterior and posterior radiocarpal ligaments. There was one case of radial artery damage while opening the joint capsule. The radial approach to the wrist as described in this work provided good access to the radial styloid process, the radioscaphoid joint and the proximal pole of the scaphoid, if the approach is done carefully to preserve the superficial branches of the radial nerve, the antebrachial cephalic vein and the radial artery. Radial styloidectomy can be performed up to 6mm from the apex without significantly damaging the radiocarpal ligaments, particularly the volar ones.

Analysis of the mechanical behavior of thin ice layers on structures including radial cracking and de-icing

In this paper multiple radial cracking in thin ice layers is studied which occurs when applying mechanical de-icing systems to aircraft structures. Brittle crack propagation is investigated based on the example of an ice layer adhering to an aluminium plate under static and dynamic normal loading. The finite element method is used in combination with cohesive zones to study the influence of the ice layer thickness, the out-of-plane displacement, and the cohesive parameters on the radial cracking process as well as on the dynamic behavior and de-icing of the structure.

Modeling of carrot root radial press process for different shapes of loading elements using the finite element method

Biological material is exposed to different type loads during the harvesting, sorting, and transport. The contact with the hard element of the box or the harvester causes damage to the internal structure. Long-term static loads and hitting by another carrot root are the most common type of mechanical damage occurring in the post-harvest process. Because of the characteristic shape of agricultural products, compression force focused on a small area. The main purpose of this study was to determine the discrete model of carrot root as well as to verify it based on the displacement distribution. For determining an experimental model, the collected data were statistically processed. To verify the obtained model, the COSMOS/M software was applied. As a result of this study, a calculation model was presented, which allowed the assessment of surface pressures on the carrot root area, which occurred during the contact with different shaped elements in selected phases of technology process.

An upper bound solution of forging load in cold radial forging process of rectangular cross-section billet

Investigation in the radial forging process for rectangular cross-section billet is scarce. In this paper, a kind of radial forging method for rectangular cross-section billet is studied. For simplicity, a rectangular cross-section billet, being forged in one hammer stroke at the middle part by two pairs of hammers, is considered. Based on a kinematically admissible velocity field, a three-dimensional model by the upper bound method (UBM) is proposed to predict the forging load in the radial forging process. Because of the non-steady flow of material in one stroke of the forging process, the forging process is divided into finite steps so that each step can be assumed as steady flow. The accuracy of the UBM model is verified by the results acquired through radial forging experiments and that of the three-dimensional finite element simulation. Then, the influences of various process parameters on the forging load and longitudinal flow of material are discussed.

Assembly deformation prediction of riveted panels by using equivalent mechanical model of riveting process

The assembly deformation of skin panels can be introduced by the riveting process. However, it is computationally costly and time consuming to conduct the numerical simulation of the riveting process for each rivet in skin panels. Here, an equivalent mechanical model of the riveting process is established to improve the computational efficiency of the deformation prediction for the riveted structure. The axial pressure beneath the rivet driven head is solved in the equivalent mechanical model. The assembly deformation of riveted panels is found to be influenced by the axial pressure significantly, challenging the traditional analogy of riveting to the radial expansion process. In addition, the dependence of the radial pressure upon the radial displacement of the rivet hole is established. The characteristic of non-uniform distribution of the radial pressure along the thickness direction is taken into consideration. The deformations of riveted structures are predicted considering various heights of the rivet driven head and different materials of the panel. The effectiveness of the proposed model is evaluated by comparing the deformation results of the numerical simulation and those of the experimental measurement. This investigation can help to predict the deformation of large riveted structures and improve the awareness of the effect of axial pressure on the assembly deformation.

Process-based modeling of tree-ring formation and its relationships with climate on the Tibetan Plateau

Response of climate warming on tree-ring formation has attracted much attention during recent years. However, most studies are based on statistical analysis, lacking understanding of tree-physiological processes, especially in the mountainous regions of the Tibetan Plateau (TP). Herein, we firstly use an updated new version of the tree-ring process-based Vaganov-Shashkin model (VS-oscilloscope) to simulate tree-ring formation and its relationships with climate factors during the past six decades. Our analyses covered 341 sampled trees growing within elevations ranging from 2750 to 4575m a.s.l. at five sampling sites across the TP. Simulated tree-ring width series are significantly (p<0.01) correlated with actual tree-ring width chronologies during their common interval periods. Starting dates of tree-ring formation are determined by temperature at all five sampling sites. After the initiation of tree stem cambial activity, soil moisture content has a significant effect on tree radial growth. Ending dates of cambial activity are driven by temperature over the whole study region. Simulated results indicate differences between wide and narrow tree-rings are mostly induced by soil moisture content, especially during the first half of the growing season, when effects from temperature variations are minor. Interestingly, we detected significantly (p<0.001) increased relative growth rates due to higher soil moisture content after the year 1985 at the five sampling sites. However, the variability of mean relative growth rates due to temperature is negligible before and after that. Based on the successful application of VS-oscilloscope modeling on the high-elevation tree stands on the TP, our study provides a new perspective on tree radial growth process and their varying relationships to climate factors during the past six decades.

Mixing and separation of liquid-liquid two-phase in a novel cyclone reactor of isobutane alkylation catalyzed by ionic liquid

To improve the existing problems of traditional isobutane alkylation catalyzed by ionic liquid reactors, a novel liquid-liquid cyclone reactor was designed for the liquid-liquid heterogeneous reaction. Compared with the traditional hydrocyclone, the novel cyclone reactor consists of two inlets, one for the light phase and one for the heavy phase. The light phase is injected into the reactor through two symmetric tangential slots in the inlet, while the heavy phase inlet is an axial entry with a guide vane. The trajectory and residence time distribution (RTD) of the light phase could influence the reaction process and product quality. In order to study the contact-mixing and separation mechanism of liquid-liquid in the novel cyclone reactor, the trajectory and residence time distribution in the reactor were investigated. Simulations using the species transport equation and experiments were performed on kerosene-water system. The tangential and radial dispersion process of oil was observed in the simulations. The simulation results showed that the mean residence time of the oil is between 0.6s and 1.0s under different operating parameters. The kerosene flow in the reactor is not a smooth flow or a complete mixing flow judging from the dimensionless variance. The separation efficiency in the simulated method was higher than 99%. The volume fraction of water in the overflow mixture was less than 5%. The deviation between the simulated and experimental results was no more than 5%, which indicated that the simulated results are reliable and accurate.

A Dynamic Model for Simulation of Hot Radial Forging Process

A comprehensive dynamic process model has been developed to investigate features of the inherently transient hot radial forging process, taking account of complex process kinematics, thermo-elastoplastic material behaviour and microstructural evolution. As an input to this model, a fully systematic thermomechanical testing matrix was carried out on a Gleeble 3800 including temperature (20-1100°C), strain (up to a true strain of 1) and strain rates (from 0.1 to >50 s-1). The proposed model can accurately capture vibration characteristics due to the high frequency short strokes during radial forging, which have been found to have a strong effect on material flow, forging load. Numerical analyses were performed to investigate the effect of different axial spring stiffnesses on forging load, strain distribution in the workpiece, and maximum axial feeding rate. It has been found that forging load increases significantly with increasing stiffness of the axial spring. The axial spring stiffness was also found to have a strong effect on determination of axial feeding rate and reduction ratio of workpiece by limiting the axial vibration amplitude of workpiece under the maximum compression of spring coil to avoid hard stop of workpiece in the axial direction during forging. It has been found that the spring stiffness does not have a strong effect on the strain distribution in the work piece. For practical application, the proposed model is applied to simulate the manufacturing process of a hollow transmission shaft using a GFM SKK10/R machine. Simulation results based on a 3 dimensional framework provide a detailed insight of material flow, residual stress and grain size evolution during the multiple pass radial forging process and the results are compared with available experimental measurements. The results provide valuable insights for process design.

2D reentrant auxetic structures of graphene/CNT networks for omnidirectionally stretchable supercapacitors.

Stretchable energy storage systems are essential for the realization of implantable and epidermal electronics. However, high-performance stretchable supercapacitors have received less attention because currently available processing techniques and material structures are too limited to overcome the trade-off relationship among electrical conductivity, ion-accessible surface area, and stretchability of electrodes. Herein, we introduce novel 2D reentrant cellular structures of porous graphene/CNT networks for omnidirectionally stretchable supercapacitor electrodes. Reentrant structures, with inwardly protruded frameworks in porous networks, were fabricated by the radial compression of vertically aligned honeycomb-like rGO/CNT networks, which were prepared by a directional crystallization method. Unlike typical porous graphene structures, the reentrant structure provided structure-assisted stretchability, such as accordion and origami structures, to otherwise unstretchable materials. The 2D reentrant structures of graphene/CNT networks maintained excellent electrical conductivities under biaxial stretching conditions and showed a slightly negative or near-zero Poisson's ratio over a wide strain range because of their structural uniqueness. For practical applications, we fabricated all-solid-state supercapacitors based on 2D auxetic structures. A radial compression process up to 1/10th densified the electrode, significantly increasing the areal and volumetric capacitances of the electrodes. Additionally, vertically aligned graphene/CNT networks provided a plentiful surface area and induced sufficient ion transport pathways for the electrodes. Therefore, they exhibited high gravimetric and areal capacitance values of 152.4 F g-1 and 2.9 F cm-2, respectively, and had an excellent retention ratio of 88% under a biaxial strain of 100%. Auxetic cellular and vertically aligned structures provide a new strategy for the preparation of robust platforms for stretchable energy storage electrodes.

Squared radial Ornstein-Uhlenbeck processes and inverse Laplace transforms of products of confluent hypergeometric functions

In this paper, we consider the squared radial Ornstein-Uhlenbeck process and associated Kolmogorov backward equation (the Laguerre heat equation). For this process, we obtain the Green function of the Laplace transform of the transition density function in terms of the con fluent hypergeometric functions and present new representations for the inverse Laplace transform of the products of confl uent hypergeometric functions.

Large Deviations for the Squared Radial Ornstein--Uhlenbeck Process

We establish large deviation principles for the couple of the maximum likelihood estimators of dimensional and drift coefficients in the generalised squared radial Ornstein-Uhlenbeck process. We focus our attention to the most tractable situation where the dimensional parameter $a>2$ and the drift parameter $b<0$. In contrast to the previous literature, we state large deviation principles when both dimensional and drift coefficient are estimated simultaneously.

Results of treatment of terrible triad injury of the elbow

Background/aim A complex elbow dislocation with associated radial head and coronoid process fractures was named the terrible triad by Hotchkiss because of historically poor outcomes. This study aimed at assessing the results and functional outcome of treatment of terrible triad injuries of the elbow. Patients and methods Between 2010 and early 2013, 11 patients suffering from terrible triad injuries of the elbow were treated at Assiut University Hospitals; eight were male individuals and three were female individuals with the mean age of 43 years (range: 26–70 years). The right elbow was injured in five, and the left was injured in six patients. The radial head was replaced by a prosthesis in five and treated by internal fixation in five patients, whereas conservative treatment was decided only in one patient; the coronoid process was fixed by screws in four, whereas four were treated by suturing of the anterior capsule and were treated conservatively. Results The mean follow-up was 13.3 months (range: 6–30 months) According to the Mayo Elbow Performance Score, three patients had excellent outcome, seven had good outcome, whereas only one had fair outcome. Conclusion Prompt surgical attention with a systematic approach to restore anatomy and provide sufficient stability to allow early motion are the key factors for a successful outcome.

Radial forging of aluminum to steel preform for the production of light-weighted wheel bearing outer race

Abstract In this research work an innovative procedure through which to manufacture the outer race of vehicles wheels bearing, aiming to reduce their total weight, is proposed. Utilizing the radial forging process, an aluminum workpiece is forged on a steel core, resulting in the same geometry for the wheel bearing outer race but allowing to achieve a considerable weight reduction. By considering the most burdensome load conditions the outer race has to stand, a stress analysis is implemented in ABAQUS/Standard by applying both bolts and bearing ball forces. Based on the stress distribution, the portion of the cross-section where the load is bearable by the aluminum 6061 alloy is identified and a new steel workpiece, realized by removing the above-mentioned volume, is created. The aluminum workpiece is then hot-forged on the steel part, replacing the removed steel volume and recreating the original shape of the bearing outer race, afterwards tested with the same load conditions to verify that the combined forged part is able to withstand the same loads. To optimize the interface behavior between hot-forged Al6061 and 45Cr steel, simple tension test specimens, realized by forging an aluminum workpiece on a steel plate, have been manufactured realizing different surface knurling on the steel plate and by pre-heating the aluminum part at different temperatures. With the proposed approach, the weight of the bearing outer race has been reduced of 35.8% while granting the same mechanical performances of the original component.

Biomass estimation of Sonneratia caseolaris (l.) Engler at a coastal area of Hai Phong city (Vietnam) using ALOS-2 PALSAR imagery and GIS-based multi-layer perceptron neural networks

This study tested the use of machine learning techniques for the estimation of above-ground biomass (AGB) of Sonneratia caseolaris in a coastal area of Hai Phong city, Vietnam. We employed a GIS database and multi-layer perceptron neural networks (MLPNN) to build and verify an AGB model, drawing upon data from a survey of 1508 mangrove trees in 18 sampling plots and ALOS-2 PALSAR imagery. We assessed the model’s performance using root-mean-square error, mean absolute error, coefficient of determination (R2), and leave-one-out cross-validation. We also compared the model’s usability with four machine learning techniques: support vector regression, radial basis function neural networks, Gaussian process, and random forest. The MLPNN model performed well and outperformed the machine learning techniques. The MLPNN model-estimated AGB ranged between 2.78 and 298.95 Mg ha−1 (average = 55.8 Mg ha−1); below-ground biomass ranged between 4.06 and 436.47 Mg ha−1 (average = 81.47 Mg ha−1), and total carbon stock ranged between 3.22 and 345.65 Mg C ha−1 (average = 64.52 Mg C ha−1). We conclude that ALOS-2 PALSAR data can be accurately used with MLPNN models for estimating mangrove forest biomass in tropical areas.

Wrist denervation of the posterior interosseous nerve through a volar approach: a new technique with anatomical considerations.

Full or selective wrist denervation is an effective treatment for chronic wrist pain. In this cadaveric study, a volar approach for prophylactic denervation of the posterior interosseous nerve (PIN) and the anterior interosseous nerve (AIN) was assessed, which can simultaneously be performed during volar approaches for distal radius fracture fixation or in combination with metalwork removal. In total 40 adult upper limbs, embalmed using Thiel's method, were investigated. Group 1 included 20 limbs of which the distances between AIN and PIN to the ulnar margin of radius were measured at levels 6, 8 and 10cm proximal to the styloid process and the distance radial styloid process to proximal border of pronator quadratus which might be useful as an intraoperative landmark. Subsequently further additional 20 adult limbs (group 2) were used. Transection of the PIN via this volar approach at the evaluated best level of step 1 was performed and evaluated by dissection via a dorsal approach. In group 1, the PIN runs within the interosseous membrane, from the ulnar border of the radius, 6.4mm (SD 2.66) at 6cm, 8.4mm (SD 2.28) at 8cm and 3.75mm (SD 5.46) at 10cm proximal to the radial styloid. The AIN runs within the interosseous membrane, from the ulna edge of the radius, 7.5mm (SD 2.4) at 6cm, 7.3mm (SD 1.95) at 8cm and 2.35mm (3.42) at 10cm proximal to the radial styloid. AIN and PIN were in close proximity at the 8-cm level which equals a 1-cm distance proximal to the pronator quadratus border. Group 2 showed a successful transection of the PIN through a single volar surgical approach in additional 18 out of 20 adult upper limbs. This study shows the local anatomy of the PIN, allowing denervation via a volar approach.

Sensory nerve supply of the distal radio-ulnar joint with regard to wrist denervation.

The objective of this study was to determine the precise departure points of the articular branches innervating the distal radio-ulnar joint from the anterior and posterior interosseous nerves. The study sample consisted of 116 upper limbs from adult human cadavers. The articular branches were prepared under the dissection microscope to take measurements using the radial styloid process as point of reference. The articular branch departed from the anterior interosseous nerve at a mean distance of 2.9 cm proximal to the styloid for a radius length of 20.5 cm, and 3.7 cm for a radius length of 26.5 cm, respectively. For the posterior interosseous nerve, the departure point was at a mean distance of 3.1 cm (radius length of 20.5 cm) and at 4.0 cm (radius length of 26.5 cm). Apart from a single branch from the posterior interosseous nerve, all articular branches were located distal to the proximal border of the pronator quadratus. Results indicate that wrist denervation from the volar approach, if performed at the proximal border of the pronator quadratus, or from the dorsal approach at a distance of 4.8 cm (for a radius length of 20.5 cm) or 6.2 cm (for a radius length of 26.5 cm) proximal to the radial styloid process, will eliminate the nerve supply to the distal radio-ulnar joint in the majority of cases.

GLOBAL ENERGETICS OF SOLAR FLARES. IV. CORONAL MASS EJECTION ENERGETICS

ABSTRACT This study entails the fourth part of a global flare energetics project, in which the mass m cme, kinetic energy E kin, and the gravitational potential energy E grav of coronal mass ejections (CMEs) is measured in 399 M and X-class flare events observed during the first 3.5 years of the Solar Dynamics Observatory (SDO) mission, using a new method based on the EUV dimming effect. EUV dimming is modeled in terms of a radial adiabatic expansion process, which is fitted to the observed evolution of the total emission measure of the CME source region. The model derives the evolution of the mean electron density, the emission measure, the bulk plasma expansion velocity, the mass, and the energy in the CME source region. The EUV dimming method is truly complementary to the Thomson scattering method in white light, which probes the CME evolution in the heliosphere at r ≳ 2 R ⊙, while the EUV dimming method tracks the CME launch in the corona. We compare the CME parameters obtained in white light with the LASCO/C2 coronagraph with those obtained from EUV dimming with the Atmospheric Imaging Assembly onboard the SDO for all identical events in both data sets. We investigate correlations between CME parameters, the relative timing with flare parameters, frequency occurrence distributions, and the energy partition between magnetic, thermal, nonthermal, and CME energies. CME energies are found to be systematically lower than the dissipated magnetic energies, which is consistent with a magnetic origin of CMEs.

Surface topography during neural stem cell differentiation regulates cell migration and cell morphology

ABSTRACTWe sought to determine the contribution of scaffold topography to the migration and morphology of neural stem cells by mimicking anatomical features of scaffolds found in vivo. We mimicked two types of central nervous system scaffolds encountered by neural stem cells during development in vitro by constructing different diameter electrospun polycaprolactone (PCL) fiber mats, a substrate that we have shown to be topographically similar to brain scaffolds. We compared the effects of large fibers (made to mimic blood vessel topography) with those of small‐diameter fibers (made to mimic radial glial process topography) on the migration and differentiation of neural stem cells. Neural stem cells showed differential migratory and morphological reactions with laminin in different topographical contexts. We demonstrate, for the first time, that neural stem cell biological responses to laminin are dependent on topographical context. Large‐fiber topography without laminin prevented cell migration, which was partially reversed by treatment with rock inhibitor. Cell morphology complexity assayed by fractal dimension was inhibited in nocodazole‐ and cytochalasin‐D–treated neural precursor cells in large‐fiber topography, but was not changed in small‐fiber topography with these inhibitors. These data indicate that cell morphology has different requirements on cytoskeletal proteins dependent on the topographical environment encountered by the cell. We propose that the physical structure of distinct scaffolds induces unique signaling cascades that regulate migration and morphology in embryonic neural precursor cells. J. Comp. Neurol. 524:3485–3502, 2016. © 2016 Wiley Periodicals, Inc.

Case control study on clinical effects of arthroscopic treatment for stenosing tenosynovitis of radial styloid process

To investigate the clinical effect of arthroscopic treatment for stenosing tenosynovitis of radial styloid process. Ninety nine patients diagnosed as stenosing tenosynovitis of radial styloid process from August, 2009 to July, 2013 were divided into three groups, including arthroscopic treatment group(32 cases), traditional operation group (34 cases) and local blocking therapy group(33 cases). Ache, tenderness, swollen situations and movement degrees of wrist joints and thumbs were observed before treatment and one week and one month after treatment. Total effective rates were calculated. Pain score of the wrist and thumb in activity state was lower in arthroscopic treatment group and traditional operation group than that in local blocking therapy group one week and one month after treatment(P=0.044, 0.039). Local pain score was lower in arthroscopic treatment group and traditional operation group than that in local blocking therapy group one month after treatment(P=0.017). The total symptom score was lower in arthroscopic treatment group and traditional operation group than that in local blocking therapy group one week and one month after treatment(P=0.007, 0.015). The effective rates one week after treatment in arthroscopic treatment group, traditional operation group and local blocking therapy group were respectively 96.9%, 94.1% and 84.8%, without significant differences(P=0.213). The effective rates one month after treatment in these three groups were respectively 93.8%, 97.1% and 72.7%, with significant differences(P=0.006). Compared with traditional operation and local blocking therapy, arthroscopic treatment has certain effects for the treatment of stenosing tenosynovitis of radial styloid process, with less operation trauma and complications, and it is worthy of clinical promotion.