Central Wire Research Articles

One Year on: Test Your Knowledge From May 2021

1. An observational study on 21 femoropopliteal chronic total occlusion (CTO) lesions treated endovascularly, investigated the effect of the guidewire route: those in which the guidewire passed through the inner half of the luminal radius (central wiring group) and those in which the guidewire passed through the outer half of the luminal radius (eccentric wiring group). According to the results of this study, which of the following findings suggest that treatment can be successfully finalized without stent implantation? 1A)Eccentric wiringB)Containing soft plaqueC)Central wiring without soft plaqueD)An extensive dissection with an arc of >180° around the circumference after balloon angioplastyE)Eccentric calcified nodule

Characteristics of pulsed nanosecond discharge excited by compact solid-state pulse forming line at atmospheric pressure air

Non-equilibrium plasma is a promising technology for the generation of ozone and removal of exhausted fuel gases. However, applications of non-equilibrium plasma are restricted by energy utilization efficiency in many industry fields. Discharge excited by nanosecond pulsed power is regarded as one of the most efficient methods. In this study, a compact five stages stacked Blumlein pulse forming line and photoconductive semiconductor switches-based power source was introduced to generate pulsed plasma. This compact source could achieve over 50 kV with 10.1 ns pulse width and 4.8 ns pulse rising time. Coaxial cylindrical reactor was employed to generate a pulsed streamer discharge driven by the nanosecond pulsed source in atmospheric pressure air. Electrical parameters of the streamer discharge have been obtained in this study, the instantaneous power dissipation exceeds 8 MW and the average energy consumption of each pulse exceeds 56 mJ. Experiments of high speed photography have been conducted to observe the evolution process. It can be found that streamer heads start from the central wire electrode and then head to the grounded cylinder electrode in all radial direction of the coaxial electrode. Triple wire-to-cylinder electrodes discharge shows that all the three coaxial discharges develop synchronously and symmetrically, which shows that is capable of generating large volume non-equilibrium diffusive streamer discharge plasma.

Superior vena cava syndrome after pacemaker implantation treated with direct oral anticoagulation

BackgroundSuperior Vena Cava (SVC) syndrome, is a quite rare but serious complication after pacemaker lead implantation; most patients are asymptomatic due to the development of adequate venous collateral circulation.Case presentationWe report a case of a 75-year-old woman who developed SVC syndrome after transvenous pacemaker implantation with complete resolution of the thrombosis after 3 months of oral anticoagulation.ConclusionsGenerally other causes as malignancy are considered to be the most common etiology of SVC syndrome, but benign iatrogenic causes, mainly intravascular devices (central vein catheters, cardiac defibrillators and pacemaker wires), are becoming increasingly common. Procedures performed on venous vasculature, causing a possible intimal injury or vein stenosis, provoked by transvenous leads, seem to be the most reasonable explanation for the observed complication.

Information storage in permalloy modulated magnetic nanowires

A long piece of magnetic material shaped as a central cylindrical wire (diameter d=50 nm) with two wider coaxial cylindrical portions (diameter D=90 nm and thickness t=100 nm) defines a bimodulated nanowire. Micromagnetism is invoked to study the equilibrium energy of the system under the variations of the positions of the modulations along the wire. The system can be thought of as composed of five independent elements (3 segments and 2 modulations) leading to 2^5=32 possible different magnetic configurations, which will be later simplified to 4. We investigate the stability of the configurations depending on the positions of the modulations. The relative chirality of the modulations has negligible contributions to the energy and they have no effect on the stability of the stored configuration. However, the modulations are extremely important in pinning the domain walls that lead to consider each segment as independent from the rest. A phase diagram reporting the stability of the inscribed magnetic configurations is produced. The stability of the system was then tested under the action of external magnetic fields and it was found that more than 50 mT are necessary to alter the inscribed information. The main purpose of this paper is to find whether a prototype like this can be complemented to be used as a magnetic key or to store information in the form of firmware. Present results indicate that both possibilities are feasible.

IATROGENIC RIGHT HEART FAILURE DUE TO THE CENTRAL VEN CATHETERIZATION: A RARE COMLPLICATION

Introduction: Central Venous Catheterization (CVC) is an invasive procedure used for many reasons in the clinics such as hemodynamic monitoring, fluid and drug administration and hemodialysis. It is unlikely problem to forget central catheter wire (CW) in intravascular area and this creates dangerous consequences. Causes such as inattention, inexperience, time constraints due to workload, fatigue and the absence of accompaniment from a more experienced clinician are the main reasons for this complication.
 Case Report: We present in this article, a case of forgotten CW starting from subclavian vein and making a ring around the tricuspid valve in the right atrium, extending to the vena iliaca communis dextra and meanwhile, preventing the tricuspid valve closure and leading to decompensated right heart failure. This complication has not been reported previously.
 Conclusion: CVC is a commonly used method. It gives us great benefit in follow-up and treatment. It should be kept in mind that the forgotten wire can cause a right heart failure secondary to mechanical tension on the tricuspid valve; as one of its complications.

Microstructure and Mechanical Properties of Wire Arc Additively Manufactured MoNbTaWTi High Entropy Alloys.

High-temperature resistant high-entropy alloys (HEAs) have attracted extensive attention due to their excellent thermodynamic stability and mechanical properties, especially at high temperatures. However, a highly effective method for large-size HEAs is still desirable but challengeable. This research reported a facile yet effective strategy for MoNbTaWTi HEAs via in-situ wire arc additive manufacturing (WAAM). The wire was MoNbTaWTi cable-type welding wire (CTWW) consisting of one center wire and seven twisted peripheral wires. Then, additive manufacturing of MoNbTaWTi high entropy alloys (HEAs) was accomplished, and various analytical techniques studied the microstructures and mechanical properties of the overlaying formed layers. X-ray diffraction showed the overlaying formed layers to contain a single disordered BCC solid solution phase with high-temperature structural stability. In addition, the single-phase BCC structure was maintained from 0 to 1400 °C. The bottom of the overlaying formed layers was made of columnar cellular structure, and the upper part resembled “cauliflower-like” fine dendrite and equiaxed crystal structure. The hardness of the overlaying formed layers averaged 533 HV0.2 at room temperature. At 1000 °C, the hardness was around 110 HV1, close to the value of Inconel 718 alloy (125 HV1). The compressive strength of the overlaying formed alloy layers displayed no sensitivity towards change in temperature from 500 to 1000 °C. As the temperature rose from 500 to 1000 °C, the compressive strength changed from 629 to 602 MPa, equivalent to only a 27 MPa decrease. The latter was much higher than the strength of Inconel 718 alloy at the same temperature (200 MPa).

Trapping of Electrons around Nanoscale Metallic Wires Embedded in a Semiconductor Medium

We predict that conduction electrons in a semiconductor film containing a centered square array of metal nanowires normal to its plane are bound in quantum states around the central wires, if a positive bias voltage is applied between the wires at the square vertices and the latter. We obtain and discuss the eigenenergies and eigenfunctions of two models with different dimensions. The results show that the eigenstates can be grouped into different shells. The energy differences between the shells is typically a few tens of meV, which corresponds to frequencies of emitted or absorbed photons in a range of 3THz to 20THz approximately. These energy differences strongly depend on the bias voltage. We calculate the linear response of individual electrons on the ground level of our models to large-wavelength electromagnetic waves whose electric field is in the plane of the semiconductor film. The computed oscillator strengths are dominated by the transitions to the states in each shell whose wave function has a single radial node line normal to the wave electric field. We include the effect of the image charge induced on the central metal wires and show that it modifies the oscillator strengths so that their sum deviates from the value given by the Thomas-Reiche-Kuhn rule. We report the linear response, or polarizability, versus photon energy, of the studied models and their absorption spectra. The latter show well-defined peaks as expected from the study of the oscillator strengths. We show that the position of these absorption peaks is strongly dependent on the bias voltage so that the frequency of photon absorption or emission in the systems described here is easily tunable. This makes them good candidates for the development of novel infrared devices.

Monitoring of prestress and bond stress of self-sensing FBG steel strand

In order to investigate the stress distribution in a prestressed steel strand and the development of bond stress between the steel strand and concrete, a new technology of encapsulating quasi-distributed fiber Bragg grating (FBG) sensor in a longitudinal groove of the center wire of a steel strand is proposed. Based on the theoretical analysis of the strain transfer between the FBG sensor and the substrate, specific parameters for measuring the stability of the FBG sensor are discussed. Tension and bending tests on unbonded prestressed reactive powder concrete beams are carried out to explore the self-sensing steel strand characteristics. The test results indicate that the quasi-distributed FBG sensor encapsulated in the center wire of the steel strand can monitor the stress distribution in the steel strand and the damage of the beam efficiently, and the maximum tensile monitoring error is only 3.42%. To analyze the distribution of the prestress and bond stress of steel strand along the anchorage length, the tensile tests are carried out on the self-sensing steel strand. The results show that the quasi-distributed FBG sensor can accurately measure the variations in steel strand stress and bond stress along the anchorage length during the tensile process.

Impact of Guidewire Route on Severe Dissection After Balloon Angioplasty for Femoropopliteal Chronic Total Occlusion Lesions: An Intravascular Ultrasound Analysis

To determine the impact of the guidewire route on severe dissection after balloon angioplasty for femoropopliteal chronic total occlusion (CTO) lesions using a new intravascular ultrasound (IVUS) assessed classification scheme corresponding to a conventional angiographic classification scheme. Images for 21 femoropopliteal CTO lesions treated endovascularly between May 2018 and December 2019 were used for analysis. IVUS images after guidewire passage and those after balloon angioplasty were evaluated at 1 cm intervals. Cross sectional images were obtained (n = 219) and divided into two groups by the guidewire route: those in which the guidewire passed through the inner half of the luminal radius (central wiring group, 139 cross sectional images) and those in which the guidewire passed through the outer half of the luminal radius (eccentric wiring group, 80 cross sectional images). Angiographically severe dissection was defined as Type C or greater according to the National Heart, Lung, and Blood Institute classification, to which six dissection morphology patterns were applied based on IVUS images (Types A - E2). Central wiring was achieved in an average of 69.6 ± 28.0% of the CTO length from per limb analysis. Among the IVUS assessed dissection morphology patterns, Types D - E2 were more frequently correlated with angiographically severe dissection than were Types A - C (57.5% vs. 13.7%, p < .001). Multivariable analysis showed that soft plaque was a predictive factor for (odds ratio [OR] 2.14; 95% confidence interval [CI] 1.007 - 4.72; p= .048) and central wiring was a protective factor (OR 0.27; 95% CI 0.14 - 0.49; p < .001) against Type D - E2 dissection patterns assessed by IVUS after balloon angioplasty. Lesions with Type D - E2 dissection patterns assessed by IVUS were correlated with angiographically severe dissection. Central wiring may be useful for preventing severe dissection after balloon angioplasty for femoropopliteal CTO lesions.

Drift-diffusion model of corona discharge in coaxial geometry due to negative lightning impulse voltage

Corona discharge at atmospheric pressure in cylindrical geometry is simulated numerically for negative lightning voltage impulse. The simulation is performed by solving the drift-diffusion-reaction equations for electrons, positive and negative ions. Spatial dependence and time evolution of the concentration of charged particles and created space electric field are used for detailed theoretical analysis of corona discharge based on the values of the transport and reaction gaseous coefficients. This exact drift-diffusion model enables clear physical picture of the corona discharge dynamics. It is used for the determination of the charge-voltage curves necessary for taking into account the corona effects in transient overvoltage calculation on transmission lines. In contrary to the previous engineering corona models, it is shown that the corona charge continues to increase although the input voltage pulse decreases after reaching its maximum value. This behavior is confirmed by measurements in a few experimental studies. Secondly, it has been shown that according to this model there are no positive streamers formation departing from central electrode or wire during decreasing edge of the input voltage pulse. The total charge simply commences to decrease when the negative ions neutralize themselves on the central electrode or wire of positive polarity. A sharp peak of corona current is observed immediately after the beginning of the intense ionization. The drift-diffusion model could also be used to check the validity of other common assumptions and predictions of previous engineering corona models.

Corrosion Characteristics of Anchor Cables in Electrolytic Corrosion Test and the Applicability of the Test Method in Study of Anchor Cable Corrosion

The selection of corrosion test method in the corrosion study of the prestressed anchors is an important issue. In this paper, the corrosion test of anchors was conducted with electrolytic corrosion test method. The corrosion characteristics of the anchor cables were examined. The effects of sodium chloride solution concentration, current, test time, and prestress level on corrosion were studied. The applicability of electrolytic corrosion method in anchor cable corrosion study is discussed subsequently. The results show that the corrosion of the anchor appears to be uniform corrosion. With the corrosion of the anchor, the central wire of the cable was basically not corroded, and the cross-sectional shape of the outer wire changes from a round to fan shape. The sodium chloride concentration and prestress level have no obvious effects on the corrosion of the anchor. The variation of test time does not affect the difference between the measured and theoretical calculated results, while a proper current in the electrolysis test may help reduce the difference. The measured corrosion rate fluctuates from −4% to 10% and tends to be higher compared with calculated results based on Faraday’s law. The study indicates that the electrolytic corrosion test is applicable in the anchor corrosion study.

Implosion mediated gas-puff hybrid X-pinch

Imploding gas-puff z-pinches are efficient sources of intense x-rays. However, the unpredictable size, number, and location of hot spots along the pinch axis make them unsuitable for applications such as point-projection radiography. Crossed wire or hybrid X-pinches, on the other hand, provide small, localized sources but require fast current rise times and must be reloaded after each pulse. In this Letter, we present the first experimental demonstration of an implosion mediated gas-puff hybrid x-pinch in which an annular gas-puff implosion is shaped and focused onto a pair of conical electrodes separated by a small gap. This setup produces an intense x-ray source with controllable timing that can be operated with or without a central wire. Because the gas-puff implosion time determines the formation of the pinch, this configuration can continue to operate efficiently as a point x-ray source for longer current pulses than conventional x-pinches.

Mini Review: Central Organization of Airway Afferent Nerve Circuits

Airway afferents monitor the local chemical and physical micro-environments in the airway wall and lungs and send this information centrally to regulate neural circuits involved in setting autonomic tone, evoking reflex and volitional respiratory motor outflows, encoding perceivable sensations and contributing to higher order cognitive processing. In this mini-review we present a current overview of the central wiring of airway afferent circuits in the brainstem and brain, highlighting recent discoveries that augment our understanding of airway sensory processing. We additionally explore how advances in describing the molecular diversity of airway afferents may influence future research efforts aimed at defining central mesoscale connectivity of airway afferent pathways. A refined understanding of how functionally distinct airway afferent pathways are organized in the brain will provide deeper insight into the physiology of airway afferent-evoked responses and may foster opportunities for targeted modulation of specific pathways involved in disease.

Finite element study of behaviour and interface force conditions of locked coil wire rope under axial loading

As a new type of cable with excellent mechanical properties, the research on the mechanical properties of the locked coil wire rope is very scarce. Owing to its special section form and steel wire contact mode, the mechanical properties of the locked coil wire rope are significantly different from those of traditional cables. In this paper, based on the ABAQUS/Explicit platform, a refined modelling method of the locked coil wire rope is proposed considering real anchorage characteristics. The purpose is to study the mechanical properties, stress distribution, interface force conditions between steel wires, and failure process of the locked coil wire rope under axial load. Based on the Feyrer theory calculation method, the stress distribution law of steel wires in the tension process of the locked coil wire rope is studied, and its failure criterion is proposed. It is found that the steel wire stress distribution is uneven in the process of cable tension. The stress of the central steel wire is greater than that of the surrounding steel wires. Cable failure generally occurs at the end. The friction between the steel wires has little effect on the tensile process, but the quality of the anchorage end affects the ultimate strength of the cable.

The “two-cut monorail” technique, for the over-the-wire removal of the Impella CP device

The Impella is a percutaneously placed intra-arterial flow pump positioned across the aortic valve for circulatory support. A limitation of the Impella is that it lacks a central wire channel, to maintain intra-arterial wire access when removing the device. Open surgical arterial cutdown is needed for the removal of the Impella CP placed emergently, without the use of preclose sutures. This case review describes an alternative removal method for the aforementioned occasions.

Experimental and numerical study on cable breakage equivalent force in cable-stayed structures consisting of low-relaxation seven-wire steel strands

Investigation of a global structural dynamics model of a cable-stayed structure subjected to the cable breakage event requires the determination of the Cable Breakage Equivalent Force with respect to time [CBEF(t)]. The CBEF(t) is an applied axial force to the structure from the stay cable considered to break which is reduced from before the breakage to after the breakage. In this study, a generic CBEF(t) in cable-stayed structures consisting of low-relaxation seven-wire steel strands is obtained experimentally and numerically. The generic CBEF(t) can be introduced in a global structural dynamics model of a cable-stayed structure directly, without the need of a very detailed and costly model for the cable breakage. An experimental program was performed as representative of a stay cable, for which three different lengths of the 3/8-inch strand were tested. A full 3D finite element (FE) model was also developed in ABAQUS/Explicit in which, by a predefined imperfection, the breakage location corresponding to the experimental observation was assigned to the FE models of the 3/8-inch and 0.6-inch strands. The results reveal that the CBEF(t) is determined in two time intervals: a tensile rectangular force in the first and a compressive force in the second. Moreover, the breakage location affects the CBEF(t), while the CBEF(t) is independent of the total length of the unbroken strand, lubricating, and the interaction between the broken cable and the damaged cable-stayed structure. The comparison between wires shows that the main part of the CBEF(t) is related to a center wire. In the last part of this paper, a simplified and generic CBEF(t) is proposed which can be used for global dynamics models of all cable-stayed structures with 3/8-inch and 0.6-inch strands.

Range‐expansion technology and fatigue performance study on the self‐sensing steel strand with an embedded fibre Bragg grating sensor

AbstractFor the protection of a fragile optical fibre with a fibre Bragg grating (FBG) sensor, the encapsulating method of embedding the FBG sensor in a longitudinal groove set in the central wire of the steel strand is presented. According to the theoretical analysis of the strain transfer and sensing capacity between the embedded FBG sensor and substrate, the requirements for the cross‐sectional size of the groove and bond‐length of the optical fibre to the self‐sensing steel strand are discussed. A prepressure technology is proposed to overcome the problem of low ultimate tensile strain of FBGs. Experiments for range‐expansion with different prepressure values were carried out. The results showed that a prepressure of 30% Pc produced the optimum range expansion of the FBG sensor with a maximum strain measurement of 12,361 με, which was 1.3 times higher than the yield strain of the strands. The analyses of the fatigue performance and static load tests on self‐sensing steel strands were also carried out. The results indicated that the self‐sensing steel strand exhibited good performance after fatigue loading operation of 2 million cycles with a maximum stress of 0.45 σb and a stress amplitude of 250 MPa. Moreover, the decrease in the monitoring strain sensitivity of the FBG was calculated to be below 3.5%, whereas the experimental data showed good linearity and repeatability. Therefore, for effective lifetime monitoring of steel strands under fatigue loading, it is suggested that the FBG sensors need to be placed under a certain prepressure before the construction and service of self‐sensing steel strand.

Semi-analytical investigation of electronic transport properties of a deformed simple cubic nanocrystal

We investigate semi-analytically the coherent electronic transport properties of a bent, twisted, compacted or stretched simple cubic nanocrystal within the nearest neighbor tight-binding approach and Green’s function technique. We take the bent, twisted, compacted and stretched part of the nanocrystal as a center wire and the other ideal parts as two semi-infinite similar left and right leads. Also, the cross-section of the wire is assumed to have square shape consisting of a finite number of atoms. We use a unitary transformation to separate the conductance modes in the ideal parts in order to calculate fully analytically center wire self-energies due to the existence of ideal leads. Then, we compute numerically the transport properties of the system by using the transformed Green’s function of the center wire which includes these self-energies. The results show that for bent and twisted configuration, some localized states form in perturbed part. The compacting has more influence on the electronic transport with respect to stretching. Also, the value of conductance at zero (Fermi) energy depends on the deformation strength in compacted and twisted nanocrystals.

Droplet formation and motion characteristics in seven-wire rotating arc electrogas welding

This paper investigates the droplet formation and motion characteristics in seven-wire rotating arc electrogas welding. A high-speed video camera was used to observe the droplet formation and motion behaviors. The forces on the droplet in different welding parameters were analyzed to explain the droplet formation and motion processes. The results show that the small droplets at the end of six peripheral wires accumulate and grow toward the small droplet at the end of the center wire under the action of the electromagnetic force, and the coupled droplet forms under the action of electromagnetic force and surface tension at the end of the center wire. Gravity, plasma flow force, and rotating force affect the fall of the coupled droplet through the arc space and show non-axial motion and axial motion with different welding currents.

The excitons in infinite potential centered multilayered coaxial quantum wire and the magnetic field effects on their properties

Abstract The exciton properties in a multilayered coaxial cylindrical quantum wire layered as A l A s / G a A s / A l x G a 1 − x A s / G a A s / A l x G a 1 − x A s are investigated. The exciton binding energies are obtained as a functions of the thicknesses of the GaAs well wires and the barrier wires formed by A l x G a 1 − x A s keeping the total radius of the structure constant and considering two by two variation of those. The binding energies has only one minimum for each variation and they all have approximate minimum binding energy values for their certain set of thicknesses. The magnetic field effects on the binding energies are also reported. The external magnetic field produces noticeably different effects on the electronic properties of the heavy hole and light hole excitons. The magnetic field can be shifted smaller strengths to obtain the minimum binding energy if the radius of the insulator wire in the center of the structure is increased.