Wire Displacement Research Articles

Effective excitation by single magnet in rotation sensor and domain wall displacement of FeCoV wire

Recently, a sensor structure consisting of magnetic wires attached directly to a rotating shaft, a pick-up coil, and a pair of magnets separately located outside the rotor was proposed. This paper presents a structure whose excitation source is just a single magnet. This structure decreases the cost of the previous sensor while retaining its advantages. For example, multiple output signals can be obtained per turn of the shaft by simply adding a corresponding number of wires, without requiring more pick-up coils and magnet pairs. In this study, the dependence of the output voltage on the pick-up coil was measured and the domain wall structure was elucidated by the measurement result.

In-vitro assessment of the forces generated by lingual fixed retainers

The aim of this article was to assess the effect of wire adaptation on the lingual surfaces of mandibular anterior teeth with 3 types of lingual retainers on the development of vertical and labiolingual forces. Ten retainers (canine to canine) were constructed from each of the following wires: Wildcat 0.0195-in heat-treated 3-strand twist-flex wire (GAC, Bohemia, NY); Penta-one 0.0215-in 6-strand as received; and Penta-one 0.0215-in 6-strand after heat treatment at 350°C for 4 minutes (both, Masel Orthodontics, Carlsbad, Calif). The retainers were bonded on each tooth of an acrylic resin model, and the model was installed in the Orthodontic Measurement and Simulation System. The vertical and labiolingual forces generated were measured for wire displacements up to 0.2 mm in 0.02-mm increments. Wire displacement of 0.2 mm exerted forces as high as 1 N on the teeth. In the vertical direction, the highest force levels were recorded for the as-received Penta-one 0.0215-in and the lowest from its heat-treated counterpart. In the horizontal plane, the as-received Penta-one 0.0215-in exerted the highest forces. The forces recorded from the lingual retainer wires during 0.2-mm simulated intrusion-extrusion and buccal-lingual movements might generate high forces that exceed 1 N and be large enough to produce unwanted tooth movement during retention. The only significant determinant of the generated forces was the amount of wire displacement and not the type of wire used in this study.

Unexpected Cause for Chest Pain

A 71-year-old man was admitted to our hospital with new onset of typical symptoms of angina on exertion corresponding to a Canadian Cardiovascular Society functional class III. The patient had undergone mitral valve replacement with a mechanical bileaflet valve (ATS medical prosthesis, ATS Medical Inc., Minneapolis, Minn.) in December 1997 and transvenous pacemaker implantation for intermittent high-degree atrioventricular node block (Biotronik Philos II DR, ventricular demand inhibited pacemaker mode VVIR0, Biotronik SE & Co. KG, Berlin, Germany) in 2006. Medical history revealed chronic kidney disease and diabetes mellitus. He had chronic atrial fibrillation and was taking oral anticoagulants. The ECG showed discrete ST depression in leads I, II, III, and aVF (Figure 1). Cardiac troponin T on admission was slightly elevated (0.046 ng/mL; reference value at our institution is <0.0014 ng/mL), and his creatine kinase-MB was negative. Anterior-posterior and lateral chest x-ray showed a fracture of the sixth sternal wire with the lateral view showing a protrusion of the cerclage loop into the anterior mediastinum (Figure 2). Transthoracic echocardiography revealed moderately …

Efficacy of intra-operative wire localisation of breast lesions using ultrasound

Ultrasound is commonly used for pre-operative wire localisation of breast lesions and involves an uncomfortable procedure for patients. Intra-operative localisation has the potential to decrease patient discomfort and avoid wire displacement. This study aimed to assess the efficacy of intra-operative wire placement by a breast radiologist.

Fabrication of smart structure using shape memory alloy wire embedded hybrid composite

AbstractShape Memory Alloys (SMA) have been actively studied in many fields utilizing their high energy density, and SMA wire embedded composite, in particular, can be used as a smart material for a load carrying structure and actuator. Composite materials such as Glass Fiber Reinforced Plastics (GFRP) can sustain large loads, but at the same time the high stiffness of the material limits the displacement range of the SMA wire embedded composite. In this research, a SMA wire embedded hybrid composite was designed and fabricated to have a larger displacement than a SMA wire embedded single composite. The hybrid composite is designed with a n‐shape and it is comprised of three parts with different stiffness materials, GFRP with higher stiffness at both ends and silicone rubber with lower stiffness in the middle to increase the displacement range of the structure. The SMA wire embedded hybrid composite can be actuated by applying an electric current through the embedded SMA wire. The fabricated composite was mechanically fastened to prevent separation between the wire and the composite laminae induced by temperature rise of the wire. The displacement of SMA wire embedded hybrid composite was examined by measuring the radius of curvature.

Efficacy of intra-operative wire localisation of breast lesions using ultrasound

Ultrasound is commonly used for pre-operative wire localisation of breast lesions and involves an uncomfortable procedure for patients. Intra-operative localisation has the potential to decrease patient discomfort and avoid wire displacement. This study aimed to assess the efficacy of intra-operative wire placement by a breast radiologist.

Slope Stability Studies Of Wabane Caldera, Western Cameroon: Impact Of Hydrology, Hydrogeology And Human Factors On Landslide Initiation

Slope analysis within the Wabane caldera was carried out to establish their stability after the 20th July 2003 landslides. A site with semi-circular fractures was selected for the installation of a vibrating wire displacement meter and a vibrating piezometer. Displacement, rainfall and pore water fluctuation were recorded from May to December 2005 in an attempt to assess the behavior of these slopes with varying rainfall intensities throughout the period. The results indicated an increase in displacement with rainfall and pore pressure from May to September and a subsequent decrease from October to December. This demonstrates the interdependence between rainfall, pore pressure and displacement. The mean monthly rate of displacement recorded was 132.3 mm/month. The highest rate of displacement from regressive plots was approximately 0.01 mm/min for the months of August/September. These are low threshold values, and one can therefore infer that they represent the beginning of a possibly new cycle to landslides projected to occur again in the future. Prolonged rainfall and increased pore water pressure had been determined as the immediate factors responsible for the initiation of the 2003 landslides.

A wire cutting test to check the temperature distribution in inductively heated cylindrical aluminium billets at semi-solid material state

A fast test has been developed to evaluate the homogeneity of the temperature field within aluminium cylindrical billets heated up to their semi-solid state. This method is based on the evaluation of force measurements during cutting of the heated specimens by a thin wire, considering that the shear stress of thixo-tropic Al-alloys is significantly deteriorated at thixo temperatures. The obtained results were explained by FEM supported calculations of the occurring thermal field within the billet. Moreover, the measured cutting forces versus the wire displacement were verified by a FEM based simulation of the introduced test. The developed method enables a fast assessment of the specimen heating uniformity and contributes to an undisturbed conduct of semi-solid high-pressure die casting.

Imaging and Management of a Caudal Mandibular Fracture in an Immature Dog

Interfragmentary wire surgical technique was used to repair a caudal mandibular fracture in a 15-week-old Labrador Retriever dog. Computed tomographic imaging aided the diagnosis and treatment planning for the application of this method. Abnormal tooth development of caudal molar teeth was related to the traumatic event and/or surgical technique. The strategically important mandibular first molar tooth was maintained. The fracture fixation method used in this case provided early return to function and radiographic evidence of expected fracture healing during a 10-month period despite wire displacement secondary to tooth eruption.

Optimized Measurements of Unmanned-Air-Vehicle Mass Moment of Inertia with a Bifilar Pendulum

A bifilar (two-wire) pendulum is a torsional pendulum consisting of a test object suspended by two thin parallel wires. The pendulum oscillates about the vertical axis. The restoring torque of the bifilar pendulum is provided by the gravitational force as rotations from the rest state cause the test object to raise slightly. The mass moment of inertia is computed using dynamic modeling, measurements of the oscillation period, and the physical dimensions of the bifilar pendulum such as the length and separation displacement of the pendulum wires. A simulation technique is described that improves estimates of the mass moment of inertia by considering the nonlinear effects of damping and large angular displacements. An analysis of the error variance of mass moment of inertia measurements is also described. The resulting expression for the error variance is used to optimize the physical parameters of the bifilar pendulum to obtain the moment of inertia measurement with the minimum error variance. Monte Carlo simulations were used to validate the parameter optimization technique. Experimental results are presented for a uniform-density test object for which the moment of inertia is straightforward to compute from geometric considerations. Results are also presented for a small unmanned air vehicle, which was the intended application for this moment of inertia measurement technique.

A Coupled Fluid-Structure Model of a Therapeutic Ultrasound Angioplasty Wire Waveguide

Ultrasonic longitudinal displacements, delivered to the distal tips of small diameter wire waveguides, are known to be capable of disrupting complicated atherosclerotic plaques during vascular interventions. These ultrasonic displacements can disrupt plaques not only by direct contact ablation but also by pressure waves, associated cavitation, and acoustic streaming developed in the surrounding blood and tissue cavities. The pressure waves developed within the arterial lumen appear to play a major role but are complex to predict as they are determined by the distal tip output of the wire waveguide (both displacement and frequency), the geometric features of the waveguide tip, and the effects of biological fluid interactions. This work describes a numerical linear acoustic fluid-structure model of an ultrasonic wire waveguide and the blood surrounding the distal tip. The model predicts a standing wave structure in the wire waveguide, including stresses and displacements, and requires the incorporation of a damping constant. The effects on waveguide response of including an enlarged ball tip at the distal end of the waveguide, designed to enhance cavitation and surface contact area, are investigated, in addition to the effects of the surrounding blood on the resonant response of the waveguide. The model also predicts the pressures developed in the acoustic fluid field surrounding the ultrasonic vibrating waveguide tip and can predict the combinations of displacements, frequencies, and waveguide geometries associated with cavitation, an important event in the disruption of plaque. The model has been validated against experimental displacement measurements with a purpose built 23.5 kHz nickel-titanium wire waveguide apparatus and against experimental pressure measurements from the literature.

Aortic insufficiency produced by stent-graft displacement

The following case report describes an unusual example of aortic valve damage caused by iatrogenic stent-graft rupture (disconnection of the proximal uncovered part of a stent-graft) during delivery of a proximal extension, resulting in the displacement of a stent-graft wire to the aortic root. The wire was extracted under cardiopulmonary bypass, using circulatory arrest, and the damaged aortic valve replaced by a mechanical valve.

A Generalized Description of the Elastic Properties of Nanowires

We report a model of nanowire (NW) mechanics that describes force vs displacement curves over the entire elastic range for diverse wire systems. Due to the clamped-wire measurement configuration, the force response in the linear elastic regime can be linear or nonlinear, depending on the system and the wire displacement. For Au NWs the response is essentially linear since yielding occurs prior to the onset of the inherent nonlinearity, while for Si NWs the force response is highly nonlinear, followed by brittle fracture. Since the method describes the entire range of elastic deformation, it unequivocally identifies the yield points in both of these materials.

First report of System Identification in Wire Electrical Discharge Machining

In this paper, the behavior of wire vibration in machining process is studied by using a system modeled on the basis of experimental results. For the purpose of examining the behavior of wire vibration, dynamical changes in the material removal process must be taken into account. Therefore, a machining system set up is modeled where the interference between the vibration system of the wire electrode and the material removal system are considered. In this system, the material removal rate and the external force output from the material removal system are the input of the vibration system, whereas, the gap distance output from the vibration system is the input source of the material removal system. In order to analyze the modeled system, some simulations of the machining process are carried out. In the analysis of these simulations, a statistical method is applied to the wire displacement. Furthermore, the mean value and the magnitude of a simulated wire displacement are quantitatively compared with the measured results. Using the modeled system, the relation between wire vibration and state variables in the system are clarified.

Development of a gripper using SMA wire

A gripper actuated by shape-memory-alloy (SMA) wire was designed and fabricated. The design took the advantage of the small linear displacement of the SMA wire to convert it into angular movement of the gripping jaws. The SMA actuation is provided by pulsing electric current from a driving circuit. With this method, the risk of the SMA being overheated can be reduced, yet providing sufficient power for the useful gripping task. This ensures that the gripper has long and lasting actuation. Testing experiments were conducted using the prototype to evaluate its working responses and reliability, including the generated force, level of excitation, reaction time, its characterization and cyclic performance. The gripping force achieved was in the range of 70–500 mN, ideal for micro-applications. This force can be varied by changing the driving current through a variable resistor. In terms of reliability, millions of gripping cycles were accomplished without any deterioration in performance. This proves that the concept of the design is feasible and the gripper is able to support a continuously long operation before any replacement of parts is required. The actuator (SMA wire) costs only US$ 0.7, much less-expensive than other actuators such as piezoelectric actuators.

ヒト肩関節を規範としたロボットアーム関節機構の開発

The purpose of this study was to develop a new joint system based on the human shoulder mechanism. The human shoulder joint is constrained by multiple muscles and ligaments which surround the ball joint, and is driven by the balance of those forces. It is thought that the construction of the human shoulder mechanism could provide motion with three degrees of freedom and with compact size and light weight in comparison with an industrial robot arm composed of the usual pin joints. Therefore, the authors thought that the new joint mechanism for a robot arm with three degrees of freedom should be a ball joint mechanism driven by wires.In the development of the new joint mechanism, we tried to construct two types of joints. These were a five-wire model and a six-wire model. An anatomical skeletal structure has been introduced to the mechanism, especially on the muscle arrangements of the human shoulder.The movability of the new joint mechanism was evaluated by the ratio of moment arm to ball radius produced from the wires that surround the ball joint. The method of estimating moment arm was to find the slope of the wire excursion against the joint angle. Thus, to compensate some deficiency of moment arm, occurring in a specific area of flexion-extension or rotation motion, the wire position corresponding to the lack of moment arm was adjusted to an adequate position using evaluation of the moment arm. As a result of improvement processes, the effective movability was ascertained in the specified movable area for the six-wire model. Sufficient movability was not acquired in the five-wire model, however, because the movable area was considerably reduced.When the joint is driven as a robot arm, an inverse kinematics must be solved. In the present study, the problem was solved by utilizing an artificial neural network (NN), which learns data sets for arm posture and wire displacement. The additional differential outputs installed in the learned NN and consideration of a theory of virtual work balance were applied to a control system to drive the joint by a feedback control system in the range of three degrees of freedom. It was properly and precisely driven by the control system on the six-wire model. Thus, the movability and capability of the new joint system of a robot arm based on the human shoulder mechanism, as described in this paper, was demonstrated to be satisfactory.

Ultrasound-guided lumpectomy of nonpalpable breast cancer versus wire-guided resection: A randomized clinical trial

The wire-guided excision of nonpalpable breast cancer often results in tumor resections with inadequate margins. This prospective, randomized trial was undertaken to investigate whether intraoperative ultrasound (US) guidance enables a better margin clearance than the wire-guided technique in the breast-conserving treatment of nonpalpable breast cancers. Patients with a preoperative histological diagnosis of nonpalpable breast cancer that could be visualized both with US and mammography were included. Patients were randomized to undergo either a wire-guided or a US-guided excision. Adequate margins were defined as >or=1 mm. Of 49 included patients, 23 were assigned to undergo wire-guided excision and 26 to undergo US-guided excision. One patient crossed over to US-guided excision after inadvertent wire displacement. Mean tumor diameter, specimen weight, and operating time were similar in both groups. The excision was adequate in 24 (89%) of 27 US-guided excisions and 12 (55%) of 22 wire-guide excisions (P =.007). US-guided excision seems to be superior to wire-guided excision with respect to margin clearance of mammographically detected and US-visible nonpalpable breast cancers. Patients do not have to undergo the unpleasant wire placement before surgery.

A quality assurance and quality control (QA QC) procedure of the monitored drift tubes (MDT) for the BIS-chambers of the ATLAS muon spectrometer

The ATLAS detector for the Large Hadron Collider at CERN of which construction has recently started, will study the products of proton collisions at energies of up to 14 TeV. One of its subdetectors is a high-resolution Muon Spectrometer designed to exploit the physics potentials of the collisions. It consists of 1206 Monitored Drift Tube (MDT) chambers, which will be built in 13 institutes of the ATLAS collaboration. Three Greek Universities (University of Athens, National Technical University and University of Thessaloniki) have undertaken the responsibility to construct 30 000 drift tubes of 1.67 length, to test them and to finally to build 128 BIS (Barrel Inner Small) chambers. Dedicated setups have been developed and automated at the National Technical University of Athens for the Quality Assurance and Quality Control (QA QC) procedures of the drift tubes. The QA QC tests include anode wire tension measurement, high voltage dark current measurement, anode wire displacement measurement and gas leak-rate measurement of the end-plugs and the cylinder. Up to now about 10 000 drift tubes have been tested.

A Closer Look at the Midsternal Stripe Sign

Reports in the literature offer conflicting data on the value of the midsternal stripe sign in diagnosing sternal dehiscence. Our purpose was to determine the frequency with which the midsternal stripe sign is present in patients with dehiscence compared with a control group without this complication and to determine whether this sign adds incremental value to the sign of sternal wire displacement in the diagnosis of dehiscence. A midsternal stripe thicker than 3 mm should raise one's suspicion of the presence of sternal dehiscence. However, this sign is rarely observed in patients with this complication and does not add incremental value to the finding of sternal wire displacement in establishing the diagnosis of dehiscence.

Improvement of the pulsed wire method for undulator magnetic-field measurement

The U10 undulator for the Pohang Light Source was measured with a pulsed wire measurement (PWM) method. By adjusting the aperture of the slotted optical switch (SOS) for PWM, the sensitivity of SOS output to the wire displacement improved significantly. A calibration table, which translates the output voltage to the displacement of wire, was obtained and the linearity of the PWM was enhanced using this table. The magnetic-field profile of the U10 undulator measured with the PWM method agrees well with that measured with Hall probe mapping. The effect of the wire dispersion on PWM is also discussed.