Central Wire Research Articles

Arc behavior and droplet transfer characteristics during oscillating laser-arc hybrid welding of 2024 Al alloy based on Zr-core-Al-shell wire

A novel zirconium (Zr)-core-aluminum (Al)-shell wire (ZCASW) combined with oscillating laser-arc hybrid welding (O-LAHW) process was employed for the welding of aluminum alloy 2024 (AA2024). The arc stability and characteristics, droplet transfer behavior and weld formation were systematically investigated. The results show that electrical signal waveform determines wire feeding rate, which affects the welding stability and weld quality. The increment in wire feeding rate increases magnetic field intensity and narrows arc cross-sectional area, which leads to arc contraction. The oscillating laser increases arc width and arc area, thereby expanding the conductive channel and greatly improving conductive ability of hybrid plasma, which promotes interactions between plasmas and helps to droplet transfer. Meanwhile, owing to the melting points differences between Zr wire and Al wire in ZCASW filler material, the melting rate of outer Al wire is larger than that of central Zr wire during welding, thereby resulting in two kinds of droplet transfer modes, and electromagnetic force and metal vapor reaction force strongly influence droplet transfer behavior. The oscillating laser improves the weld quality, which is deteriorated due to the appearance of spatters as wire feeding rate increases. When 1 m/min wire feeding rate is selected, a perfect formation is obtained. The current study offers insight into the formation mechanism of high-quality weld and welding stability during O-LAHW of AA2024 combined with ZCASW filler material.

Superior vena cava syndrome: presentation of 7 cases and literature review

Superior vena cava syndrome (SVCS) is the result of obstruction of venous flow through the SVC. Mortality due to SVCS is rare (0.3%); however, the median survival in patients with SVCS secondary to malignancy is 6 months. Extrinsic occlusion due to malignancy is the most common cause; however, intraluminal thrombosis secondary to central venous catheters and pacemaker wires represents 30% of cases. The SVC is the main drainage pathway for the head, neck, and upper torso region, so SVCS is characterized by facial and neck edema, dyspnea, and distension of the neck and chest veins. Symptoms vary depending on the severity, location, and speed of onset of the obstruction and the establishment of collateral veins. Diagnosis is based on clinical presentation and imaging studies such as chest angiotomography and digital subtraction venography (gold standard). Regarding treatment, radiation therapy and chemotherapy were considered first-line; however, nowadays endovascular therapy (ET) (angioplasty, stent placement, and catheter-directed thrombus extraction) has demonstrated higher success rates and lower recurrence rates. Surgical diversion is reserved for cases of extensive venous thrombosis or occlusion not amenable to ET. We conducted a literature review and described 7 cases of SVCS treated with successful ET and their main complications at the national cancer institute of Mexico. SVCS is a condition with a diagnostic challenge. Currently, the use of endovascular treatment through angioplasty and stent placement leads to immediate improvement in patients, thus establishing it as first-line treatment.

Comparative performance analysis of straight and harped prestressing seven-wire strands: High-strength stainless steel vs. conventional carbon steel

This paper presents an experimental investigation into the utilization of high-strength stainless steel (HSSS) strands systems in prestressed bridges. The study delves into the effects of localized bent and harping of seven-wire HSSS strand systems under various harping angles and curvatures produced by the deviators. For comparison purpose, conventional carbon steel (CS) strands were also studied using the same experimental parameters. It was anticipated that CS strands would exhibit better performance due to its superior post-yied ductility. To closely mimic the state of practice in the precast plant, two types of deviators were designed and used in this investigation. A comparable harping capacity was observed for HSSS strands relative to CS strands, despite the CS strands exhibiting higher strain compared to the HSSS strands. Upon reaching their breaking load, necking of all seven wires was predominantly observed for HSSS, whereas the CS strands failed due to the fracture of only one or two outer wires. Due to the lack of ductility in the HSSS stand, it was expected to have the lower bent capacity, especially at higher harping angles. Despite the significant difference in post-yied ductility, the study revealed that both HSSS and CS strands exhibit similar performance. To further understand the similarity and difference in behaviour of these two materials, scanning electron microscopy (SEM) examinations were conducted on both HSSS and CS wires to visualize the bending effects on the microstructure level after bending the center wire at different angles.

Development and characterization of a coaxial strain-sensing cable integrated steel strand for wide-range stress monitoring

Abstract Monitoring the stress of steel strands, from initial tension to eventual failure, is paramount for assessing structural safety and understanding its failure mechanism. Current monitoring methods are restricted in measuring stress only until yielding because of their limited range. This study proposes a novel coaxial strain-sensing cable (CSSC) based intelligent steel strand (CSSC-ISS), which has both functions of force-bearing and self-sensing. First, the prototype design of CSSC-ISS and the sensing principle of CSSC are introduced. Then, a fabrication method of small-diameter CSSC is proposed, which is then encapsulated with glass fiber reinforced polymer (GFRP) material, forming a GFRP sensing rod (GFRP-SR). The next step involves replacing the strand’s central wire with the GFRP-SR, culminating in the creation of the CSSC-ISS. Finally, Laboratory tests show that the CSSC has excellent strain-sensing performance with a resolution of at least 100 µε and a measurement range of 150,000 µε. The GFRP-SR offers good sensing potential and comparable mechanical strength to standard GFRP rods. Notably, the CSSC-ISS could measure stress up to strand failure, retaining 87.9% tensile strength and 88.7% elastic modulus compared to standard steel strands. It is verified that the CSSC-ISS can consistently measure its stress condition throughout its life cycle without compromising its load-bearing potential.

Microstructure, mechanical properties, and fracture behavior of multi-core through steel wire reinforced brass composite rod produced by a solid-liquid continuous casting and composite technique

A multi-core through steel wire reinforced brass composite rod was fabricated using a solid-liquid continuous casting and composite technique. Microstructure evolution, interface, mechanical properties, and deformation behavior of the composite rod during the room temperature tensile process were studied. The results showed that the steel wires in the composite rod were distributed in a regular hexagonal shape, forming a brass/steel interface with good metallurgical bonding. After annealing at 700 °C for 1h, the tensile strength of the composite rod was 376 MPa, and the elongation to failure was 46.3 %, whose tensile strength was 21 % higher than that of the brass cladding single steel wire composite rod with the same steel percentage. During uniform tensile deformation, each steel wire in the composite rod experienced a consistent and uniform tensile stress. When the tensile deformation became unstable, the central steel wire experienced the highest level of tensile stress, initially leading to the occurrence of necking and fracture. As the tensile strain increased, the brass grains underwent twisting and rotation. In addition, the steel grains were elongated along the tension direction, and the number of low-angle boundaries increased. The straight brass/steel interface was transformed into a wavy pattern with a good bonding interface, indicating that the composite rod exhibited excellent synergetic deformation capability. The mixing laws based on hybrid effects have good applicability to multi-core through steel wire reinforced brass composite rod, with a strength error of less than 7 %.

Transient plasma enhanced combustion of solid rocket propellants

We demonstrate the use of nanosecond pulse transient plasma (NPTP) to improve the control (and acceleration) of the combustion of solid rocket propellants. Here, we fabricate end-burning propellant samples (i.e., grains) with a co-axial center wire electrode using hydroxyl terminated polybutadiene (HTPB), isodecyl pelargonate (IDP), modified diphenyl diisocyanate (MDI), and ammonium perchlorate (AP) as the fuel, plasticizer, curative, and oxidizer, respectively. High voltage (20 kV) nanosecond pulses (20 nsec) produce a streamer discharge that provides electronic throttling of the solid rocket propellant. These studies are carried out over a wide range of oxidizer mass fractions, including those considered insensitive munitions (IM). In addition, real time imaging is performed characterizing the plasma-formation, evolution of the ignition process, and plasma enhanced flame-fuel coupling. We believe the plasma-based mechanisms of enhancement are 3-fold: 1.) The plasma provides highly energetic electrons that drive new chemical reaction pathways via highly reactive atomic species such as H, O, and Cl, 2.) The plasma sputters chunks of the solid fuel material up into the flame where it is combusted, producing an agitated flame profile. 3.) The plasma provides increased turbulence and multi-scale mixing due to hydrodynamic effects (i.e., ionic winds), which further improves the combustion process. Having electronic control of the burn rate introduces the ability to “throttle” solid rocket motors and introduce new flight profile options beyond a pre-selected profile such as the typical boost-sustain profile. While we are unable to quantify the burn rate or thrust from these relatively simple observations, we observe clear evidence of the effect of the plasma on the combustion of these solid rocket fuels even at high oxidizer content.

Influence of the argon admixture on the reactive oxide species formation inside an atmospheric pressure oxygen plasma jet

In this work, a new atmospheric pressure plasma generated in a wire-to-multiwire dielectric barrier discharge on pure oxygen is introduced. This special geometry of 13 wires (one central wire and 12 ones on the external tube) is feeding by a radio frequency (RF) power (13.56 MHz, 1 kW) and produces a stable discharge. The capacity of this device to produce oxygen reactive species and the influence of Ar gas mixture (1–3%) on this production are investigated. The main characteristics of this DBD plasma are measured using optical emission spectroscopy techniques. The rotational, vibrational, and excitation temperatures along with the electron density are determined from OH (A2Σ → X2Π) band and the Stark broadening of the hydrogen atomic line at 486.1 nm, respectively. The temporal evolution and spatial distribution of charged and reactive species in this plasma are also numerically studied by a Global scheme and a two-dimension fluid model based on drift–diffusion approximation. A kinetic dominated by electron collisions is obtained for this plasma. The generation and movement of electrons, positive and negative ions in the wire-to-multiwire configuration are analyzed and discussed according to changes the electric field and plasma frequency. It is shown that the density of both charged and reactive species increases by adding a small amount of argon to the oxygen plasma while the electron temperature reduces in this configuration. A high level of agreement is observed between the experimental and simulation results for the electron density and temperature in this DBD plasma.

An analytical model for asymmetric wire breaking in unbonded prestressed single- and multi-strands

A novel analytical model is proposed to improve the accuracy of predicting the mechanical response of a strand with asymmetrically broken wires. This model incorporates a new approach to compute the contact force between the broken wire and the duct. When there is more than one asymmetrically broken wire, the previous method cannot handle this situation due to the large deflection of the center wire near the breaking end. This deflection results in a significant contact force between the center and broken wires. The omission of this force in the previous method leads to unrealistic solutions for two or three asymmetrically broken wires. This paper addresses the issue appropriately. The calculated results have been compared with those from a previous experiment, demonstrating satisfactory agreement. Furthermore, the proposed analytical model has been adopted to predict the mechanical behavior of the broken wire in multi-strand scenarios relevant to a prestressed concrete bridge. The contact force between strands is accurately calculated. The findings indicate that the axial force of the asymmetrically broken wire in multi-strands can recover after a short distance from the broken end. This recovery is attributed to the confinement effect of the other strands.

Analysis of the quality of aluminum overhead conductors after 30 years of operation

Overhead power conductors (OHL), which are installed in transmission and distribution lines, are designed for a service life of min. 30–50 years. During this time, the OHL conductors should work in a safe and fault-free state with the highest current capacity. This article refers to the testing of aluminum conductors after 30 years of operation. The mechanical properties and structural characteristics of the conductor were tested. The analysis of the quality of the supplied wire samples carried out with a scanning microscope allowed us to distinguish three types of wire damage, namely: corrosion on the surface of the outer layer, wires, local melting, and loss of cross section and wire breakage. On the basis of a detailed analysis of the areas of damage to wires from the tested OHL conductors, it can be stated that the main cause of their breakage is local smelting areas caused by an electric arc.High temperatures affect local material melting, leading to a large reduction and the consequence of strength decreasing. This situation leads to the loss of the conductor's carrying capacity and ultimately to its destruction. During 30 years, conductors had to be subjected to frequent short circuits caused by changing weather conditions, i.e., high wind or storms. The paper dealt with the results of the mechanical properties test, which showed that the aluminium wires are lower than those required by the standard. The greatest degradation of the strength properties occurs on the wires of the outer layer of conductor. The center wires show a negligible reduction in tensile strength.

Short term Functional Outcomes of Reverse Shoulder Arthroplasty Following Three-Dimensional Planning is Similar Whether Placed with a Standard Guide or Patient Specific Instrumentation (PSI).

Preoperative assessment of the glenoid and surgical placement of the initial guide wire are important in implant positioning during reverse total shoulder arthroplasty (rTSA). Three-dimensional (3D) computed tomography (CT) and patient specific instrumentation (PSI) have improved the placement of the glenoid component, but the impact on clinical outcomes remains unclear. The purpose of this study was to compare short term clinical outcomes after rTSA based on intraoperative technique for central guidewire placement in a cohort of patients that had preoperative 3D planning. A retrospective matched analysis was performed from a multicenter prospective cohort of patients who underwent rTSA with preoperative 3D planning and a minimum of 2-year clinical follow-up. Patients were divided into 2 cohorts based on the technique utilized for glenoid guide pin placement: 1) Standard manufacture guide (SG) that was not customized or 2) PSI. Patient reported outcomes (PROs), active range of motion (ROM), and strength measures were compared between the groups. The ASES score was used to assess the minimum clinically important difference (MCID), substantial clinical benefit (SCB), and patient acceptable symptomatic state (PASS). One hundred seventy patients met the study criteria, including 56 performed with SGs and 122 with PSI. There was no difference in PROs between cohorts. There were no significant differences in the percentage of patients that achieved an ASES MCID, SCB, or PASS. Improvement in internal rotation to the nearest spinal level (p < .001) and at 90° (p = .002) were higher in the SG group and, but likely explained by differences in glenoid lateralization utilized. Improvement in abduction strength (p < .001) and external rotation strength (p = .010) were higher in the PSI group. rTSA performed following preoperative 3D planning leads to similar improvement in PROs regardless of whether a SG or PSI are utilized intraoperatively for central glenoid wire placement. Greater improvement in postoperative strength was observed with the use of PSI, but the clinical significance of this finding is unclear.

Low energy electronic recoils and single electron detection with a liquid Xenon proportional scintillation counter

Liquid xenon (LXe) is a well-studied detector medium to search for rare events in dark matter and neutrino physics. Two-phase xenon time projection chambers (TPCs) can detect electronic and nuclear recoils with energy down to kilo-electron volts (keV). In this paper, we characterize the response of a single-phase liquid xenon proportional scintillation counter (LXePSC), which produces electroluminescence directly in the liquid, to detect electronic recoils at low energies. Our design uses a thin (10–25 μm diameter), central anode wire in a cylindrical LXe target where ionization electrons, created from radiation particles, drift radially towards the anode, and electroluminescence is produced. Both the primary scintillation (S1) and electroluminescence (S2) are detected by photomultiplier tubes (PMTs) surrounding the LXe target. Up to 17 photons are produced per electron, obtained with a 10 μm diameter anode wire, allowing for the highly efficient detection of electronic recoils from beta decays of a tritium source down to ∼ 1 keV. Single electrons, from photoemission of the cathode wires, are observed at a gain of 1.8 photoelectrons (PE) per electron. The delayed signals following the S2 signals are dominated by single-photon-like hits, without evidence for electron signals observed in the two-phase xenon TPCs. We discuss the potential application of such a LXePSC for reactor neutrino detection via Coherent Elastic Neutrino Nucleus Scattering (CEνNS).

Real-time seam tracking during narrow gap GMAW process based on the wide dynamic vision sensing method

Welding torch horizontal seam tracking is a crucial condition to realize automatic welding of narrow gap gas metal arc welding (NG-GMAW) robots. In the present study, a real-time welding seam tracking technology based on the passive vision sensor is proposed. To this end, a wide dynamic range (WDR) vision sensor is used to capture real-time welding images. In order to realize real-time identification of the welding torch center deviation in the process of swinging arc in a welding bead, a welding seam tracking algorithm based on the window information fusion (WIF) is proposed. In this regard, the local feature moving window recognition (LMWR) algorithm is applied to extract the groove center. Based on the improved welding image processing program, the weld pool center and welding wire center are prepared for seam tracking. In this regard, considering the trifling variation of groove and weld pool center, the welding horizontal deviation is obtained by combining them with welding wire center calculation. Aiming at establishing a correlation between consecutive images, the Kalman filter is used to estimate the deviation optimally. The tracking algorithm is successfully verified in the weld bead with a horizontal deviation, and the tracking accuracy of ±0.47 mm is achieved. The performed analyses demonstrate that the developed algorithm meets the requirements of real-time seam tracking in the GMAW process of the welding robot.

First-in-human trial of Center Wire for neuroendovascular therapy to avoid guidewire-related complications.

An exchange maneuver is useful for the delivery of devices to target vessels. However, hemorrhagic complications can occur due to vessel perforation during an exchange maneuver. In addition, the exchange is often challenging due to unfavorable anatomy. Center Wire is an exchange-length wire with a nondetachable stent that was developed to improve navigation and stability during exchange maneuvers. The aim of this study is to investigate the safety and efficacy of Center Wire of the anchor wire technique during neuroendovascular treatment. Ten patients with intracranial aneurysms were treated after signing a Certified Review Board-approved consent. Anchor wire technique was used in all patients to navigate catheters to the target vessel for aneurysm treatment. Anchor wire technique was successfully applied in all 10 cases using Center Wire. One device-related incident of vasospasm occurred which was asymptomatic. No device-related dissection, perforation, or thromboembolic events occurred. One patient had intraoperative aneurysm rupture during coil placement which was treated immediately without clinical consequences. Two patients had postoperative ischemic strokes due to thrombotic occlusion of branches originating from the aneurysm which were unrelated to the device. This first-in-human trial of Center Wire demonstrated the safety and efficacy of the anchor wire technique for neuroendovascular treatment in a strictly regulated prospective registry trial.

Reflection-enhanced gain in traveling-wave parametric amplifiers

The operating principle of traveling-wave parametric amplifiers is typically understood in terms of the standard coupled mode theory, which describes the evolution of forward propagating waves without any reflections, i.e. for perfect impedance matching. However, in practice, superconducting microwave amplifiers are unmatched nonlinear finite-length devices, where the reflecting waves undergo complex parametric processes, not described by the standard coupled mode theory. Here, we present an analytical solution for the TWPA gain, which includes the interaction of reflected waves. These reflections result in corrections to the well-known results of the standard coupled mode theory, which are obtained for both 3-wave and 4-wave mixing processes. Due to these reflections, gain is enhanced and unwanted nonlinear phase modulations are suppressed. Predictions of the model are experimentally demonstrated on two types of unmatched TWPA, based on coplanar waveguides with a central wire consisting of i) a high kinetic inductance superconductor, and ii) an array of 2000 Josephson junctions.

Broadband 2D phase-gradient metasurface for linearly-polarized waves by suppressing Lorentz resonance of meta-atoms.

Metasurfaces have exhibited versatile capacities of controlling electromagnetic (EM) waves due to the high degree of freedom of designing artificially engineered meta-atoms. For circular polarization (CP), broadband phase gradient metasurfaces (PGMs) can be realized based on P-B geometric phase by rotating meta-atoms; while for linear polarization (LP), realization of broadband phase gradients has to resort to P-B geometric phase during polarization conversion and polarization purity has to be sacrificed for broadband properties. It is still challenging to obtain broadband PGMs for LP waves without polarization conversion. In this paper, we propose the design of 2D PGMs by combining the inherently wideband geometric phases and non-resonant phases of meta-atom, under the philosophy of suppressing Lorentz resonances that usually bring about abrupt phase changes. To this end, an anisotropic meta-atom is devised which can suppress abrupt Lorentz resonances in 2D for both x- and y-polarized waves. For y-polarized waves, the central straight wire is in perpendicular to electric vector Ein of incident waves, Lorentz resonance cannot be excited although the electrical length approaches or even exceeds half a wavelength. For x-polarized waves, the central straight wire is in parallel with Ein, a split gap is opened on the center of the straight wire so as to avoid Lorentz resonance. In this way, the abrupt Lorentz resonances are suppressed in 2D and the wideband geometric phase and the gradual non-resonant phase are left for broadband PGM design. As a proof of concept, a 2D PGM prototype for LP waves was designed, fabricated and measured in microwave regime. Both simulated and measured results show that the PGM can achieve broadband beam deflection for reflected waves for both x- and y-polarized waves in broadband, without changing the LP state. This work provides a broadband route to 2D PGMs for LP waves and can be readily extended to higher frequencies such as terahertz and infrared regimes.

Real-Time Damage Self-Diagnosis and Self-Localization Brillouin Distributed Optical Fiber–Fiber-Reinforced Polymer Composite Smart Cables

Cables are important components of long-span space structures, cable-supported bridges, slopes, and so on. However, they often suffer from damage such as wire breakage, corrosion, and anchor head loosening, which threatens structural safety seriously. Therefore, it is very important to diagnose and localize their damage. To address this problem, a real-time damage self-diagnosis and self-localization smart cable is proposed. It is made of a polyethylene cover pipe and some parallel intelligent steel strands with the Brillouin distributed monitoring capability. Fiber-reinforced polymer (FRP) and optical fiber are put together in the thermosetting molding process to form the intelligent central wire of each intelligent steel strand. When the side wire of the steel strand reaches the ultimate load, the intelligent central wire only reaches about 50% of its ultimate load, so it can be used in the real-time monitoring of side wires. Numerical models of seven-wire steel strands with different lengths were established, and the broken wire damage was simulated by changing coupling conditions in single and multiple damage cases. To further verify the proposed smart cable, experiments were carried out based on two intelligent steel strands with the length of 34.5 m. Experimental damage cases were simulated by cutting side wires at different positions under different loads. Both numerical and experimental results show that the change in the tension strain of the intelligent central wire can indicate the damaged location of the broken side wire. For a healthy steel strand, the tension strain of the central wire is a constant value; for a damaged steel strand, damage can be localized according to the strain waveform of the intelligent central wire and its ratio of peak strain to stable strain. The proposed smart cable has functions of real-time stress self-sensing, damage self-diagnosis, damage self-localization, damage self-warning of any side wire, and its central wire has excellent corrosion resistance; it can be well used in life-cycle real-time structural health monitoring of cable structures/substructures, which dramatically reduces the probability of cable accidents, and lays a good foundation for smart civil structures.

Evaluating the optimum electric power consumption for forced convection of an EHD induced circulating flow through a circular tube: A numerical study

In this study, the effect of using EHD forced convection heat transfer through a circular tube is numerically investigated to prepare the required data sets to find the optimum configuration considering the Nusselt number and friction factor. To gain the required results, the Reynolds numbers and the applied voltages are set to 3000–7000 and 9–13.5 kV, respectively. Moreover, the variety of using miscellaneous placement positions of the central wire emitter, up to 30%, in combination with collector section angles in the range of θ = 90°–360°, are simultaneously investigated. The results of different section angles show that the Nusselt number has increased between 2.35 and 4.76 times compared to the non-EHD mode. Similarly, for the various eccentricities, the Nusselt number has increased between 2.35 and 5.05 times. In the final step, upon the gathered data, a Pareto front of optimal points was deduced for the hydraulic-thermal performances against the power consumption, and the optimum design was highlighted.

Optical Properties of 2D Micro- and Nanostructures of ZnO:K

ZnO nano- and microstructures doped with K were grown by the Vapor-Solid method. Wires and needles are the main morphology observed, although some structures in the form of ribbons and triangular plates were also obtained. Besides these, ball-shaped structures which grow around a central wire were also detected. Raman and cathodoluminescence investigations suggest that variations in morphology, crystalline quality and luminescence emissions are related to the different lattice positions that K occupies depending on its concentration in the structures. When the amount is low, K ions mainly incorporate as interstitials (Ki), whereas K occupies substitutional positions of Zn (KZn) when the amount of K is increased. Electron Backscattered Diffraction shows that ribbons and triangular plates are oriented in the (0001) direction, which indicates that the growth of this type of morphologies is related to distortions introduced by the Ki since this position favors the growth in the (0001) plane. In the case of the ball-shaped structures, the compositional analysis and Raman spectra show that they consist of K2SO4. Finally, the capability of the elongated structures to act as waveguides and optical resonators was investigated. Due to the size of the K ion, practically double that of the Zn, and the different positions it can adopt within the ZnO lattice (Ki or KZn), high distortions are introduced that compromise the resonators performance. Despite this, quality factor (Q) and fineness (F) show acceptable values (80 and 10 at 544 nm, respectively), although smaller than those reported for doping with smaller size alkali, such as Li.

A pilot multi-institutional study to evaluate the accuracy of a supine MRI based guidance system, the Breast Cancer Locator™, in patients with palpable breast cancer

BackgroundEvaluate whether the Breast Cancer Locator™ (BCL), a novel guidance system based on supine MRI images, can be safely and effectively deployed by several surgeons at multiple sites. MethodsPatients with palpable breast cancer underwent supine MRI at their local institution. A three dimensional (3D) digital image of the tumor in the breast was derived from supine MRI images and used to generate 1) an interactive 3D virtual image of the tumor in the breast (Visualizer) and 2) a plastic bra-like form that allowed the surgeon to place a central wire and bracketing wires in the breast (BCL). The primary objective was to determine the proportion of patients who had the central localization wire deployed within the cancer on specimen mammogram. ResultsFourteen patients were enrolled at 4 different sites by 6 surgeons. BCLs were successfully manufactured for all patients. The central wire was deployed within the tumor on specimen mammogram in 12 of the 13 patients who had a central wire placed (92%). The cancer was excised with negative margins in 14/14 cases (100%). No adverse events occurred. ConclusionsSupine MRI image acquisition was accomplished successfully across multiple sites. Multiple surgeons utilized the BCL system to localize cancers accurately and safely.

Observation and analysis of a large banana orbit in the diocotron mode of a coaxial Malmberg–Penning trap

The diocotron mode of an off-axis electron column is studied in a coaxial version of the Malmberg–Penning trap. Measurements of the diocotron frequency as a function of the bias on the central conductor agree well with a derived theory including finite-length corrections and confinement potential contributions. When the experimental parameters are adjusted to give a very low diocotron frequency, the column motion abruptly changes from an axis-encircling orbit to a large banana-shaped orbit in the r−θ plane with extent Δθ≈270° and Δr/R≈0.25, where R is the wall radius. This banana motion is apparently in response to a previously unknown background construction asymmetry. The size of the asymmetric potential is deduced from orbit data and found to be 45–100 mV. Theoretical modeling shows this to be consistent with a small radial offset δ in the center wire position of δ/R=0.034. Implications and applications of these findings are discussed and a note on obtaining the line density of an electron column in a coaxial trap is given.