Tip Of Rod Research Articles

Clovis points and foreshafts under braced weapon compression: Modeling Pleistocene megafauna encounters with a lithic pike.

Historical and ethnographic sources depict use of portable braced shaft weapons, or pikes, in megafauna hunting and defense during Late Holocene millennia in North and South America, Africa, Eurasia and Southeast Asia. Given the predominance of megafauna in Late Pleistocene North America during the centuries when Clovis points appeared and spread across much of the continent (13,050-12,650 cal BP), braced weapons may have been used in hunting of megaherbivores and defense against megacarnivores. Drawing from historical examples of pike use against lions, jaguars, boars, grizzlies, carabao and warhorses we consider the possibility of a fluted lithic pike. Associated osseous rods have been problematic as Clovis foreshafts due to the bevel angle and the apparent weakness of the splint haft when great strength is needed for deep penetration in megafauna hunting. However our review of Late Holocene pike use in megafauna encounters indicates the sharp tip becomes less important after hide or armor has been pierced because compression is sustained. Thus, foreshaft collapse after hide entry may not limit but rather increase the efficacy of the braced weapon. We conduct preliminary static experiments to model a fluted pike that adjusts during compression such that haft collapse and point detachment (when point jams on impact with bone) preserve the fluted biface, beveled rod and wooden mainshaft tip. In addition to Clovis point attributes and association with osseous rods, potential archaeological correlates of Clovis pike use include the high frequency of Clovis point isolates and concentrations of complete points with unbutchered mammoth remains at sites such as Naco in Arizona.

Tip shape effects on the axial-flow-induced vibration of a cantilever rod

The influence of tip shape on flow-induced vibration of a cantilever rod subjected to axial water flow is experimentally investigated, through optical tracking of the rod movement and mapping of the instantaneous flow field around the rod tip. The experimental setup consists of a vertical cantilever rod housed within a tube. The rod tip shapes considered in this study include a blunt tip and cones with height-to-diameter ratios of 0.5, 1, and 2. The experiments were conducted across a Reynolds number range between 20k to 100k in both clamped-free and free-clamped configurations, representing opposite flow directions. The rod tip motion was captured using fast video image tracking, whereas the flow field near the rod tip was obtained using particle image velocimetry (PIV). The rod vibration dynamics exhibited a primarily fuzzy period-1 behavior, characterized by a periodic motion with a chaotic component. Flutter-like oscillation and buckling were also observed at higher Reynolds numbers, depending on the flow direction. The mechanisms of fluid-structure interaction involved turbulent buffeting and movement-induced excitations. Unsteady flow separation around the rod tip was identified as a further contributing mechanism to flow excitation. In the clamped-free configuration, unsteady flow separation was more pronounced for the cone tips due to the increased rod surface area in the wake region, leading to larger vibration amplitude. In the free-clamped configuration, flow separation effects were more prominent for the blunt tip, as the streamlined cone shapes were less prone to flow separations. Overall, the rod with a blunt tip resulted in smaller displacement in the clamped-free configuration, while the rods with cone tips led to smaller displacement in the free-clamped configuration.

Piezo‐Turned Magnet Rotation for ELF/SLF Cross‐Medium Communication in Omni‐Direction

AbstractExtremely/super low frequency (ELF/SLF) electromagnetic (EM) waves offer efficient propagation in challenging cross‐medium environments. However, conventional coil antennas, when emitting ELF/SLF EM waves, face constraints related to size, radiation efficiency, and high power consumption. To overcome these limitations, a disc‐rod structured piezoelectric rotating resonator is proposed, which can turn a NdFeB permanent magnet disc into rotation with an impressive high‐speed up to 10 000 r min−1 via wobbling motion of the rod tip, effectively generating ELF/SLF magnetic field radiation via rotational oscillation other than common linear and swinging oscillation of the magnetic dipole moments. The piezo‐turned magnetic rotation (PTMR) method leads to a two to five‐fold enhancement in magnetic field emission compared to existing piezo‐actuated acoustic resonant antennas, and a 370 times higher emitting efficiency compared to the traditional coil antenna with a comparable size. In contrast to unidirectional EM wave radiation at their solely resonant frequencies, the PTMR antenna showcases omnidirectional B‐field radiation with continuous tunability in a dual frequency band spanning from 10 to 100 Hz. Moreover, an air–seawater cross‐medium magnetic field communication is successfully demonstrated. With outstanding performance metrics, the PTMR antenna emerges as a promising solution for efficient long‐distance ELF/SLF cross‐medium communication.

Mechanical and wear behavior of al-steel solid state cladding produced by friction stir surfacing

Friction surfacing (FS) is a solid-state cladding method that produces a coating with minimum dilution and good metallurgical bonding. Deposition of aluminium over mild steel with using fusion based joining process is not feasible sue to the formation of iron aluminide and Fe and Al are metallurgically immiscible to each other. Hence, deposition of aluminium on steel with solid-state condition is feasible and most viable option. During the process, a rotating consumable rod is rubbed against the substrate plate under an applied axial load. The friction between rod and substrate generates a visco-plastic layer at the end of rod tip. The high temperature and pressure at interfaces aids in the cladding of the rod material on the substrate. Aluminium alloy 6351 T6 rod of 22 mm diameter was used as consumable material for surfacing on a 6mm thick SA516 Gr70 steel substrate plate. Optimized process parameters were used for the final experimental trials. Multilayer samples generated at constant Friction Surfacing variables were subjected to Pin-on-disc wear test at 40N load. Mechanical interlocking was also observed at the interface of the layers. The process was also observed to produce extremely fine grain microstructures of the deposited material due to the hot forging action involved resulting in superior wear properties.

The Painlevé paradox in three dimensions: resolution with regularization

The classical Painlevé paradox consists of a slender rigid rod slipping on a rigid rough surface. If the coefficient of friction μ is high enough, the governing equations predict that the rod would be driven into the surface. The paradox is well studied in two dimensions, in which the paradox is resolved via regularization, where the rod tip meets the surface. In this paper, we consider the three-dimensional problem. There are two significant differences in three dimensions. Firstly, sticking now occurs on a co-dimension 2 surface. This results in a non-smooth problem, even when the three-dimensional problem is regularized. Secondly, unlike the highly singular two-dimensional problem, trajectories can now enter the inconsistent region from slipping, requiring a completely new analysis. We use blowup to investigate the problem and show that a key part of the dynamics of the regularized three-dimensional Painlevé problem is governed by a type I Painlevé equation.

Simulation of the NuScale SMR and Investigation of the Effect of Load-Following on Component Lifetimes

The NuScale small modular reactor (SMR) has been modeled using the Virtual Environment for Reactor Applications multiphysics environment and the results compared with the publicly reported data in the Design Certification Application. The results show an excellent agreement for the compared axial and radial power distributions, temperature coefficients of reactivity, boron and control rod worths, and fast neutron flux. This NuScale model is then used to investigate the effect of different operational modes on reactor components to determine how the flexible load-following operation may affect control rod and reactor pressure vessel (RPV) lifetimes. The control rod degradation is confirmed to primarily affect the silver-indium-cadmium rod tip. The degradation rate is observed to follow a nonlinear function of core power level where the increase in degradation decreases with insertion depth. For the variation in core power levels expected with current load-following schemes, the total control rod degradation is found to be mild, at 5% to 10% of usable life per cycle for a reactor operating at <80% power. Nonetheless, this enables load-following strategies to be confirmed and/or modified to ensure that control rods do not need to be replaced during the 60+ year life of the reactor. The RPV degradation was found to be almost directly proportional to the core power level and was not overly sensitive to flux shape perturbations. Future work is planned using these damage functions to optimize operation over multiple NuScale SMR units and to develop strategies for prognostics and health management.

Combined experimental-numerical analysis of A356 aluminum alloy friction surfacing on AA2024 aluminum alloy substrate

This study examined the influence of the rotational speed of an A356 aluminum alloy consumable rod on thermo-mechanical issues, microstructure, and the wear resistance of coating during friction surfacing on an AA2024 aluminum alloy. The study utilized a comprehensive experimental-numerical analysis to fulfill its objectives. The findings reveal that the width and thickness of the coating increase by 7 and 18% percent, respectively, as the rotational speed of the consumable rod is augmented from 600 to 800 revolutions per minute (rpm). A higher rotational speed of the consumable rod facilitates plastic deformation of the material within it, enabling softer material to be deposited on the substrate's surface under reduced axial force. Simulation outcomes display that the maximum plastic strain is experienced on the coating's upper surface, which contacts the tip of the consumable rod. Upon moving toward the interface between the coating and the substrate, the degree of plastic strain rapidly diminishes. In the coatings produced by rotational speeds of 600 and 800 rpm, a fine grain layer forms on the upper side of the coating that comes into contact with the consumable rod's tip. Friction surfacing utilizing a rotational speed of 800 rpm, a traverse speed of 125 mm/min, and an axial feeding rate of 100 mm/min, results in increases of 9 and 38% in hardness and wear resistance respectively, compared to the AA2024 substrate.

The relationship between the occurrence of anterior synechiae and localization of a burn wound of the cornea

The objective of this study was to determine the relationship between the occurrence of anterior synechiae and the localization of a burn wound of the cornea. For this purpose, 10 male Wistar rats were selected, one year old, with an average weight of 200 grams (two experimental groups of 5 rats each). Wounds were inflicted on animals injected into sevoflurane anesthesia by touching the cornea with the tip of a copper rod having 1.0 mm in diameter and heated to t – 480-500 °C. The required degree of burn was achieved by the time of contact of the thermal source with the cornea and was monitored visually with an increase of 4-6 times. A 10% lidocaine solution was used for local anesthesia. 1.0% atropine solution was used to remove the iris from the zone of phlogogen exposure. Corneal wounds were inflicted on rats in the first experimental group in the central region, and on rats in the second experimental group in the projection area of the iris.The observation was carried out for three weeks with constant monitoring and photodocumentation of the wound condition using a microscope "jingleszcn 315W" at magnification x 6.0. The study was carried out before instillation of atropine and 10.0 minutes after.The experiment showed that significant differences in the course of the wound process were observed by day 15, there were no anterior synechiae in the experimental group 1, while in animals in the experimental group 2, the reaction of the iris to atropine shows the inability to open the pupil evenly around the circumference, which indicates the presence of a adhesion process.Thus, the results of the conducted studies have shown that the probability of the development of iridocorneal synechiae depends on the location of the inflammatory process on the cornea.

An Improved Design of the MultiCal On-Site Calibration Device for Industrial Robots.

MultiCal is an affordable, high-precision measuring device designed for the on-site calibration of industrial robots. Its design features a long measuring rod with a spherical tip that is attached to the robot. By restricting the rod's tip to multiple fixed points under different rod orientations, the relative positions of these points are accurately measured beforehand. A common issue with MultiCal is the gravitational deformation of the long measuring rod, which introduces measurement errors into the system. This problem becomes especially serious when calibrating large robots, as the length of the measuring rod needs to be increased to enable the robot to move in a sufficient space. To address this issue, we propose two improvements in this paper. Firstly, we suggest the use of a new design of the measuring rod that is lightweight yet has high rigidity. Secondly, we propose a deformation compensation algorithm. Experimental results have shown that the new measuring rod improves calibration accuracy from 20% to 39%, while using the deformation compensation algorithm, the accuracy increases from 6% to 16%. In the best configuration, the calibration accuracy is similar to that of a measuring arm with a laser scanner, producing an average positioning error of 0.274 mm and a maximum positioning error of 0.838 mm. The improved design is cost-affordable, robust, and has sufficient accuracy, making MultiCal a more reliable tool for industrial robot calibration.

Erratum: Eyestalk Ablation to Increase Ovarian Maturation in Mud Crabs.

Erratum: Eyestalk Ablation to Increase Ovarian Maturation in Mud Crabs.

Experiments on axial-flow-induced vibration of a free-clamped/clamped-free rod for light-water nuclear reactor applications

The flow-induced vibration of a cantilever rod confined in a pipe and exposed to an axial water flow has been experimentally investigated using a simple test piece designed to be informative for water-cooled nuclear reactor fuel rods. The Reynolds number was varied between 7.43 k and 82.5 k: a range that significantly extends the scope of existing data. Measurements were carried out using non-contact techniques: fast video imaging was used to track the rod motion, whilst particle image velocimetry was employed to resolve the flow field. The sources of excitation that sustain the rod vibration include turbulent buffeting, movement-induced excitation, and flow separation at the rod tip, whilst the observed dynamic responses of the rod comprise a fuzzy period-1 motion, a flutter-like large-amplitude oscillation, and buckling. Since both the rod vibration and the flow field are measured, the present data are particularly suited for numerical methodology development and validation.

Seeing our hand or a tool during visually-guided actions: Different effects on the somatosensory and visual cortices

The processing of proprioceptive information in the context of a conflict between visual and somatosensory feedbacks deteriorates motor performance. Previous studies have shown that seeing one's hand increases the weighting assigned to arm somatosensory inputs. In this light, we hypothesized that the sensory conflict, when tracing the contour of a shape with mirror-reversed vision, will be greater for participants who trace with a stylus seen in their hand (Hand group, n = 17) than for participants who trace with the tip of rod without seen their hand (Tool group, n = 15). Based on this hypothesis, we predicted that the tracing performance with mirror vision will be more deteriorated for the Hand group than for the Tool group, and we predicted a greater gating of somatosensory information for the Hand group to reduce the sensory conflict. The participants of both groups followed the outline of a shape in two visual conditions. Direct vision: the participants saw the hand or portion of a light 40 cm rod directly. Mirror Vision: the hand or the rod was seen through a mirror. We measured tracing performance using a digitizing tablet and the cortical activity with electroencephalography. Behavioral analyses revealed that the tracing performance of both groups was similarly impaired by mirror vision. However, contrasting the spectral content of the cortical oscillatory activity between the Mirror and Direct conditions, we observed that tracing with mirror vision resulted in significantly larger alpha (8–12 Hz) and beta (15–25 Hz) powers in the somatosensory cortex for participants of the Hand group. The somatosensory alpha and beta powers did not significantly differ between Mirror and Direct vision conditions for the Tool group. For both groups, tracing with mirror vision altered the activity of the visual cortex: decreased alpha power for the Hand group, decreased alpha and beta power for the Tool group. Overall, these results suggest that seeing the hand enhanced the sensory conflict when tracing with mirror vision and that the increase of alpha and beta powers in the somatosensory cortex served to reduce the weight assigned to somatosensory information. The increased activity of the visual cortex observed for both groups in the mirror vision condition suggests greater visual processing with increased task difficulty. Finally, the fact that the participants of the Tool group did not show better tracing performance than those of the Hand group suggests that tracing deterioration resulted from a sensorimotor conflict (as opposed to a visuo-proprioceptive conflict).

Spatial Confinement of Single-Drop System to Enhance Aggregation-Induced Emission for Detection of MicroRNAs

Due to high incidence, poor prognosis, and easy transformation into pancreatic cancer (PC) with high mortality, early diagnosis and prevention of acute pancreatitis (AP) have become significant research focuses. In this work, we proposed a magnetic single-drop microextraction (SDME) system with spatial confinement to enhance the aggregation-induced emission (AIE) effect for simultaneous fluorescence detection of miRNA-155 (associated with AP) and miRNA-196a (associated with PC). The target miRNAs were selectively recognized by the hairpin probe and triggered the DNA amplification reaction; then, the DNA strands with two independent probes of G-quadruplex/TAIN and Cy5 were constructed on the surfaces of the magnetic beads. The SDME process, in which a drop containing the fluorescence probes was formed at the tip of the magnetic microextraction rod rapidly within 10 s, was performed by magnetic extraction. In this way, G-quadruplex/TAIN was enriched owing to the spatial confinement of the single-drop system, and the fluorescence signal given off (by G-quadruplex/TAIN) was highly enhanced (AIE effect). This was detected directly by fluorescence spectrophotometry. The approach achieved low limits of detection of 2.1 aM for miRNA-196a and 8.1 aM for miRNA-155 and wide linear ranges from 10 aM to 10 nM for miRNA-196a and from 25 aM to 10 nM for miRNA-155. This novel method was applied to the fluorescence detection of miRNAs in human serum samples. High relative recoveries from 95.6% to 104.8% were obtained.

Agglomeration of aerosol using small equipment with two small aerial ultrasonic sources

We have developed an ultrasonic agglomeration device that is considerably smaller than previous devices. We used a round-groove small aerial ultrasonic source, which is a compact, intense aerial source of ultrasonic waves. This ultrasonic source generates a large transverse vibration displacement using a circular vibrating plate with a round groove near the tip of the transmission rod, and it produces intense sound waves perpendicular to the vibration plane. In this paper, a compact agglomeration device containing two round-groove small aerial ultrasonic sources was developed, and the agglomeration efficiency was investigated by varying the volume of the device and the input power to the ultrasonic source. The results showed that although this device is small, it has a sufficient agglomeration effect.

Experimental study on positive corona discharge characteristics in plane-single/double earthed rods air gaps under negative DC voltage

In order to analyze the corona discharge characteristics at the grounding object tip under the thundercloud electric field environment, scaled simulation test has been conducted on corona discharge in the plane-single/double earthed rods air gap. Five gap configurations with three different grounding rods were built during experiments. Factors as rod tip curvature, voltage and gap configuration have been considered in detail. Corona voltage, corona current and the number of ultraviolet photons were all recorded. The grounding rod tip curvature radius can affect corona discharge processes at grounding rod tip. With increasing applied negative DC voltage, five typical corona processes of dark discharge, burst streamer corona, periodic streamer corona, glow corona and brush discharge occurred at conical and spherical grounding rod tip (r=0.75cm), but under d=5cm and d=10cm no glow corona and brush corona appeared at spherical grounding rod tip (r=1.25cm). It is much easier for grounding rod tip with smaller curvature to form glow corona phenomenon. The mean value Iav of periodic streamer corona current pulse amplitude decreases with grounding rod tip curvature radius, while the mean corona current pulse width and pulse interval increases. For grounding rod with conical tip, there is little difference of average current pulse amplitude between periodic streamer corona and brush corona; for grounding rod with spherical tip (r=0.75cm), the mean value Iav of brush corona pulse amplitude increases to 3595.8 μA which has increased by a factor of about 36. The photon number at conical grounding rod tip is larger than that at spherical grounding rod tip at low voltage but the relation reverses as the applied voltage exceeds a critical value. The shielding effect of two grounding rods in plane-double rods air gaps increased with spherical grounding rod curvature radius and decreases with the lateral gap distance between two grounding rods.

Optimal Geometry for Plasmonic Hot-Carrier Extraction in Metal-Semiconductor Nanocrystals.

Plasmon-induced energy and charge transfer from metal nanostructures hold great potential for harvesting solar energy. Presently, the efficiencies of charge-carrier extraction are still low due to the competitive ultrafast mechanisms of plasmon relaxation. Using single-particle electron energy loss spectroscopy, we correlate the geometrical and compositional details of individual nanostructures to their carrier extraction efficiencies. By removing ensemble effects, we are able to show a direct structure-function relationship that permits the rational design of the most efficient metal-semiconductor nanostructures for energy harvesting applications. In particular, by developing a hybrid system comprising Au nanorods with epitaxially grown CdSe tips, we are able to control and enhance charge extraction. We show that optimal structures can have efficiencies as high as 45%. The quality of the Au-CdSe interface and the dimensions of the Au rod and CdSe tip are shown to be critical for achieving these high efficiencies of chemical interface damping.

Staphylococcal Periscope proteins Aap, SasG, and Pls project noncanonical legume-like lectin adhesin domains from the bacterial surface

Staphylococcus aureus and Staphylococcus epidermidis are frequently associated with medical device infections that involve establishment of a bacterial biofilm on the device surface. Staphylococcal surface proteins Aap, SasG, and Pls are members of the Periscope Protein class and have been implicated in biofilm formation and host colonization; they comprise a repetitive region ("B region") and an N-terminal host colonization domain within the "A region," predicted to be a lectin domain. Repetitive E-G5 domains (as found in Aap, SasG, and Pls) form elongated "stalks" that would vary in length with repeat number, resulting in projection of the N-terminal A domain variable distances from the bacterial cell surface. Here, we present the structures of the lectin domains within A regions of SasG, Aap, and Pls and a structure of the Aap lectin domain attached to contiguous E-G5 repeats, suggesting the lectin domains will sit at the tip of the variable length rod. We demonstrate that these isolated domains (Aap, SasG) are sufficient to bind to human host desquamated nasal epithelial cells. Previously, proteolytic cleavage or a deletion within the A domain had been reported to induce biofilm formation; the structures suggest a potential link between these observations. Intriguingly, while the Aap, SasG, and Pls lectin domains bind a metal ion, they lack the nonproline cis peptide bond thought to be key for carbohydrate binding by the lectin fold. This suggestion of noncanonical ligand binding should be a key consideration when investigating the host cell interactions of these bacterial surface proteins.

Nonconforming Three-Dimensional Model for PWR Control Rod Movements Without Homogenization and Cusping Effect

Based on previous work on the IDT solver, enhanced geometrical capabilities have been developed to handle accurate modeling of pressurized water reactors (PWRs). This work particularly focuses on the tridimensional model of the control rods. We propose a transport-based model to avoid the control rod cusping effect generated by homogenizations. Due to the geometry of a PWR core, the height of a node generally ranges from 10 to 20 cm. On the other hand, the control rods move along the vertical direction within the PWR core with axial steps of 1 to 2 cm. As a result, a control rod cluster may be partially inserted into a set of Cartesian nodes, thus requiring a heterogeneous representation of the cross sections along z. In traditional three-dimensional (3-D) transport codes, piecewise distributed cross sections are not allowed within a single node. Consequently, despite the heterogeneous nature, the node has to be homogenized. Because of sharp axial heterogeneity, the cross sections cannot be represented by polynomial expansions at the interface between the control rod tip and the water. Currently, the solvers of APOLLO3® do not allow for nonconformal geometries along the z-axis, i.e., all two-dimensional regions have the same number of planes. Lately, high-fidelity transport-based core solvers have dealt with this issue by proposing flux-weighting homogenization techniques. Nevertheless, the simple homogenization triggers a discontinuity in the first derivative of the curve representing the variation of the fundamental eigenvalue as the control rods are inserted into the reactor. This nonphysical phenomenon is known as the control rod cusping effect. Several numerical remedies have been proposed over the years to remove it. For instance, in diffusion, the PN or SPN method, and Fanning and Palmiotti have proposed a heterogeneous variational nodal method (VNM). Another heterogeneous VNM was developed by Smith et al. in 2003. In this method, each heterogeneous node is split into subelements with uniform cross sections. The flux is then developed by finite spatial trial functions. The nodal functional is constructed by the functional of all subelements in the node. In this work, discrete ordinates linear short characteristics are applied to 3-D heterogeneous Cartesian cells (HCCs). To ensure accurate representation of the control rod movements, each heterogeneous node, represented by a HCC, is the combination of an inner local tridimensional grid and a set of cylinders representing the fuel rod in its exact shape. The new geometrical model generates local nonconforming geometries. Spatial integrals over the HCC are performed using modular tridimensional ray tracing. The ray-tracing technique is based on the combinatorial geometry composed of cylinders and the local XYZ grid. In this manner, a single HCC can be equipped with several local steps to follow exactly the axial displacement of the control rod. The IDT provides a conformal 3-D Cartesian mesh with heterogeneous nonconformal 3-D nodes to eliminate such an issue. Each node represents a geometrical pattern named HCC. Neither a homogenization procedure nor a mesh adjustment is needed by taking advantage of the geometrical model provided by the HCC. Numerical results show that the HCC transport model can eliminate the cusping effect and obtain accurate power distribution with relatively higher efficiency and accuracy.

Analysis of Factors Influencing Postoperative Femoral Head Collapse in Patients With Ficat I, II, and III Stages of Aseptic Necrosis of the Femoral Head.

To investigate the factors influencing postoperative femoral head collapse (FHC) in patients with Ficat I, II, and III stages of aseptic necrosis of the femoral head (ANFH). Retrospective analysis of 178 patients with ANFH admitted to our hospital from October 2018 to October 2021 was studied, and patients were categorized into the FHC group and no FHC group according to whether FHC occurred after surgery. The influencing factors causing postoperative FHC were analyzed by univariate and multifactor logistic regression. In the collapsed group, there were statistically significant differences in etiology, extent of necrosis, mechanism of injury, preoperative waiting time, Japanese Femoral Necrosis Research Society staging, distance from the tip of the tantalum rod to the center of necrosis, and Harris score after treatment ( P < 0.05). The etiology, extent of necrosis, mechanism of injury, preoperative waiting time, Japanese Femoral Osteonecrosis Research Society classification, distance between the tantalum rod tip and the center of necrosis, and Harris score after treatment were set as independent variables, and postoperative FHC in patients with Ficat I, II, and III stages of ANFH was used as the dependent variable in the univariate logistic regression analysis. Hormonal osteonecrosis of the femur, extent of necrosis, type C1 and type C2 in the Japanese Society for the Study of Femoral Osteonecrosis staging, and distance of the tip of the tantalum rod from the center of necrosis are risk factors for postoperative FHC in patients with Ficat I, II, and III stages of ANFH.

Dissolution of Ti–N inclusions in liquid titanium during electron beam melting

The dissolution of Ti–N solids in liquid titanium was investigated using experimental and numerical methods. To characterize the dissolution rate and the transport phenomena associated with the dissolution process, cylindrical Ti–N rods were immersed into a molten pool of commercially pure titanium produced using an electron beam button furnace. Tests were conducted for various immersion times to observe the evolution in the rod tip profile and measure the volume loss. Generally, the volume fraction of dissolved solid increases with increasing immersion time. A numerical model has been developed to describe the experimental process and aid in understanding the dissolution process. Overall, the predicted volume loss for different immersion times agrees well with the experimental measurements. An effective mass transfer coefficient, in the range of 4.2 × 10−5 to 4.9 × 10−5 m/s, has been derived based on the model results for the experimental conditions examined (e.g. interface velocities and temperatures in the range of 0.09 – 0.11 m/s, and 1766 – 1778 °C, respectively).