Wire Position Research Articles

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.

Adverse event using Medtronic NIM™ EMG endotracheal tube on a patient receiving anesthesia for hemithyroidectomy: a case report

BackgroundThe neural integrity monitor (NIM) electromyogram (EMG) endotracheal (ET) tube is a widely used device to monitor neural response through muscle activity. It is helpful in surgical procedures with high risk of damaging delicate structures in the head and neck. This case provides a thorough analysis of an adverse event that was encountered in the operating room, which others can hopefully learn from.Case presentationWe are reporting a case in which a patient undergoing hemithyroidectomy had experienced an adverse event using the Medtronic NIM™ EMG endotracheal tube. After successful induction and intubation, confirming the proper positioning of the electrode wires was necessary before the incision could be made. Upon reexamination, the patient suddenly became difficult to ventilate with increased peak airway pressure, decreased tidal volume, and end tidal CO2. This episode lasted approximately 15 min and the patient’s condition remained stable despite low tidal volumes. The problem was unexpectedly resolved upon deflation of the cuff of the ET tube.ConclusionsThere are several similar reports of these endotracheal tubes causing obstruction, especially those in which overinflation of the cuff caused cuff herniation and blockage of the Murphy eye and the bevel. It is currently believed that the design of this tube allowed for the obstruction to occur. The patient’s short body habitus may have also been a small contributing factor. The distance that the electrodes must sit within the vocal cords to the tip of the bevel is longer in this type of ET tube compared with a standard ET tube. The distance from the true vocal cords to where the cuff sits in the trachea is also greater in this model NIM EMG tube. There was no confirmation of the exact obstructive process that took place, however, confirming the tube and cuff positioning would have been optimal.

Accuracy of guide wire placement for femoral neck stabilization using 3D printed drill guides

BackgroundThe goal of stabilization of the femoral neck is to limit morbidity and mortality from fracture. Of three potential methods of fixation, (three percutaneous screws, the Synthes Femoral Neck System, and a dynamic hip screw), each requires guide wire positioning of the implant(s) in the femoral neck and head. Consistent and accurate positioning of these systems is paramount to reduce surgical times, stabilize fractures effectively, and reduce complications. To help expedite surgery and achieve ideal implant positioning in the geriatric population, we have developed and validated a surgical planning methodology using 3D modelling and printing technology.MethodsUsing image processing software, 3D surgical models were generated placing guide wires in a virtual model of an osteoporotic proximal femur sawbone. Three unique drill guides were created to achieve the optimal position for implant placement for each of the three different implant systems, and the guides were 3D printed. Subsequently, a trauma fellowship trained orthopedic surgeon used the 3D printed guides to position 2.8 mm diameter drill bit tipped guide wires into five osteoporotic sawbones for each of the three systems (fifteen sawbones total). Computed Tomography (CT) scans were then taken of each of the sawbones with the implants in place. 3D model renderings of the CT scans were created using image processing techniques and the displacement and angular deviations at guide wire entry to the optimal sawbone model were measured.ResultsAcross all three percutaneous screw guide wires, the average displacement was 3.19 ± 0.12 mm and the average angular deviation was 4.10 ± 0.17o. The Femoral Neck System guide wires had an average displacement of 1.59 ± 0.18 mm and average angular deviation of 2.81 ± 0.64o. The Dynamic Hip Screw had an average displacement of 1.03 ± 0.19 mm and average angular deviation of 2.59 ± 0.39o.ConclusionThe use of custom 3D printed drill guides to assist with the positioning of guide wires proved to be accurate for each of the three types of surgical strategies. Guides which are used to place more than 1 guide wire may have lower positional accuracy, as the guide may shift during multiple wire insertions. We believe that personalized point of care drill guides provide an accurate intraoperative method for positioning implants into the femoral neck.

A Survey on the Progress of Computer-Assisted Vascular Intervention

Vascular diseases seriously threaten human health. As a commonly used minimally invasive surgery, vascular interventional diagnosis and treatment faces a variety of clinical burdens, so the support of computer-aided technology is urgently needed. In recent years, the rapid development of extravascular and intravascular medical imaging technology and artificial intelligence methods has promoted the related research of computer-assisted vascular intervention technology. The organic relationship between the basic content and key technologies of computer-assisted vascular intervention and its applications are reviewed and systematically analyzed, including multi-modal medical angiography image analysis, catheter guide wire position tracking, vascular associated lesion characteristics, morphological recognition, and other hot issues, and the relationships between the above contents and surgical planning and surgical navigation are analyzed. It is concluded that the clinical application trend in this field is to combine the integration of diagnosis and treatment with vascular interventional robot technology. Through the analysis of research status and development trends, it is concluded that the challenges faced by various research content are: the accuracy of the segmentation model to quantify the vascular structure and the completeness of topology extraction, intervention path vectorization and accuracy of multimodal information fusion, correlation between vascular anatomical labeling and surgical path navigation, and the level and evaluation method of human-computer interaction in vascular intervention. Analysis shows that in the process of solving these problems, the artificial intelligence diagnosis and treatment technology will continue to be promoted, especially the rapid development and clinical application of robot-assisted vascular intervention.

Effect of precursor gas inlet position relative to hot wire cells in HWC-IP-PECVD systems for low-temperature graphene growth

ABSTRACT Graphene growth at low temperatures was investigated by integrating a hot wire cell made from coil-shaped tungsten into a plasma-enhanced chemical vapour deposition (PECVD) system. It was found that the suitable position of the hot wire was such that the precursor gas comes out of the end of the gas pipeline and directly flows into the hot wire along its axis. This position puts the gas pipeline outside of plasma area, yielding uninterrupted plasma. The obtained films, which were grown at a low temperature between 290 °C to 300 °C, showed the presence of sharp G band in Raman spectra, indicating the presence of graphitic carbon structure and was confirmed by X-Ray Diffraction data. Also, sharp D band was detected in Raman spectra, which indicated that the film contains many defects. In addition to the nature of ion bombardment in the PECVD process, the defects were due to the addition of O-H functional groups and the formation of sp3 C-H in the samples, as shown in the FTIR spectra. Due to these defects, the Raman spectra obtained of the films showed very weak 2D bands, suggesting that our samples were in the form of graphene oxide.

Real-Time Monitoring System for Thermocouple Inhomogeneity Equipment

Thermocouple inhomogeneity equipment was developed to measure the Seebeck coefficient characteristic in each wire position based on the effect of temperature exposure along the thermocouple wire. Temperature and distance sensors are used to measure the temperature output of the heating system and the movement of the thermocouple position. We developed a real-time measurement system to monitor the measurement of the thermocouple sensor based on a microcontroller. This monitoring system is needed to monitor changes in the ice bath during measurement, if the ice bath was unstable or being melting, it can affect the output voltage of the thermocouple. The program was compiled and uploaded to ESP 32 then monitoring data with an open-source internet of things called Thingspeak was used as a platform to retrieve and display the collected data. Real-time monitoring of distance from ultrasonic and temperature of heat source (heat gun) can be accessed through web applications and smartphones. The data were analyzed based on conditions for Seebeck value of inhomogeneity and validated with standard calibration using the liquid bath. This study has been considered successfully implemented that performs on IoT platforms and was adaptively ready to monitor thermocouple inhomogeneity equipment.

P59 A COMPLEX PCI IN A CARDIOGENIC SHOCK NSTEMI PATIENT NEEDING PTA AND LEFT VENTRICLE ASSISTANCE

Abstract A 72–years–old man, smoker, type 2 DM and hypertension in history, was admitted for NSTEMI complicated by cardiogenic shock; Echocardiogram revealed LV dilatation with severe disfunction (EF 20%), moderate mitral regurgitation; he started inotropic support and high dose diuretics, then he needed dialysis and positioning of a temporary PM. Coronary angiography revealed chronic total occlusion (CTO) of the left anterior descending artery (LADA) and CTO of the right coronary artery (RCA). A first CTO PCI procedure was attempted for the LADA occlusion, with the support of IABP, using an antegrade approach, polimeric wire (ASAHI Fielder) and more penetrating ones (ASAHI Gaia I and II), unable to gain the true lumen beyond the occlusion. A second attempt was planned, with the support of Impella CP device for left ventricle assistance; due to critical stenosis in the right common iliac artery, a PTA with stenting (8/38 mm) was preparatory for that. For the second attempt a dual coronary approach was prepared (6 F Amplatz left 1,0 for RCA and 7 F XB 3,5 for left coronary artery); at first a novel antegrade attempt was pursued with a step–up technique (ASAHI wires: Gladius, Gaia I, II and III, Conquest pro), ineffective to reach the true lumen distally the occlusion. The retrograde approach was then pursued, through a collateral originating from the acute marginal branch of the RCA to the distal segment of LADA, using the Caravel microcatheter with ASAHI wires Sion blue, Sion black, Suoh 03, effective to reach the distal cap of the occlusion, this one passed by the Gladius wire. The ASAHI RG3 externalization wire (330 mm) was then used, entering from the radial access and the amplatz catheter for the RCA, reaching the XB catheter in the left coronary artery through a Guideliner extension catheter, and externalized in the femoral access. IVUS analysis was then used to confirm good wire position and the vessel calibers, so pre–dilatation was done and 3 drug–eluting stents were implanted (2,25/23 + 3,25/38 + 3,5/18 mm) distal–to–proximal overlap, with final post–dilatation, obtaining a good final result on angiography and IVUS. During the 4–hours procedure clinical condition was stable and Impella was removed with a rapid weaning; the double pre–mounted Proglide device was used for femoral hemostasis. 5 days after the patient was discharged, II–III NYHA class, 25% EF. At the 3 months f–up he was asymptomatic in good clinical condition, 30% EF, he refused ICD implant.

Analysis and Calculation of Crosstalk for Twisted Communication Cables in Umbilical Cable

An umbilical cable is a compactly integrated cable consisting of electrical power cables, communication (electric signal) cables, and chemical transposition tubes. An umbilical cable is widely used in developing oil and gas resources of deep and ultra-deep water. With the increment of the length and the functional integration of umbilical cables, the crosstalk becomes a crucial issue in the cable design, and needs to be evaluated carefully before the fabrication and installation. Moreover, the twisted structure of communication cable cores has incurred extra difficulties to the crosstalk calculation. Nevertheless, it is not an easy task to model the complex twisted structure in existing models and methods of the crosstalk computation. In this regard, this paper proposes a numerical methodology for the crosstalk calculation considering the multi-conductor twisted structure of the cable cores. In the methodology, the four-wire twisted structure is modelled as a cascade of uniform multiconductor transmission line (MTL) sections, each wire section covering a length of 1/4 pitch, with abrupt interchanges of wire positions at the ends. The chain-parameter equation is introduced to describe the voltage and current transfer relationship in each MTL section. To obtain the numerical solutions of the twisted cable system, the port constraint equations and the permutation matrices are also required and developed. The per-unit-length parameters of the umbilical cable system are computed by numerical methods. The feasibility to engineering applications and accuracy of the proposed methodology is validated by experimental results, and the crosstalk characteristics of communication cables in a typical umbilical cable under different operating conditions are investigated.

Diagnostic Performance of CT-Derived Fractional Flow Reserve in Australian Patients Referred for Invasive Coronary Angiography

Non-invasive computed tomography (CT)-derived fractional flow reserve (FFRCT) is computed from standard coronary CT angiography (CTA) datasets and provides accurate vessel-specific ischaemia assessment of coronary artery disease (CAD). To date, the technique and its diagnostic performance has not been verified in the Australian clinical context. The aim of this study was to describe and compare the diagnostic performance of FFRCT and CTA for the detection of vessel-specific ischaemia as determined by invasive fractional flow reserve (FFR) in the Australian patient population. One-hundred-and-nine patients (219 vessels) referred for clinically mandated invasive angiography were retrospectively assessed. Each patient underwent research mandated CTA and FFRCT within 3 months of invasive angiography and invasive FFR assessment. Independent core laboratory assessments were made to determine visual CTA stenosis, FFRCT and invasive FFR values. FFRCT values were matched with the corresponding invasive FFR measurement taken at the given wire position. Visual CTA stenosis ≥50%, FFRCT values ≤0.8 and invasive FFR values ≤0.8 were considered significant for ischaemia. Per vessel accuracy, sensitivity, specificity, positive predictive value and negative predictive value of FFRCT were 80.4%, 80.0%, 80.6%, 64.9% and 90.0% respectively. Corresponding values for CTA were 75.1%, 87.1%, 69.2%, 58.1% and 91.7% respectively. In receiver operating characteristic curve analysis, FFRCT demonstrated superior area under the curve (AUC) compared with CTA in both per vessel (0.87 vs 0.77, p=0.004) and per patient analysis (0.86 vs 0.74, p=0.011). Per vessel AUC of combined CTA and FFRCT was superior to CTA alone (0.89 vs 0.77, p<0.0001). In this cohort of Australian patients, the diagnostic performance of FFRCT was found to be comparable to existing international literature, with demonstrated improvement in performance compared with CTA alone for the detection of vessel-specific ischaemia.

Research on the Influence of Bond Wire Lift-Off Position on the Electro-Thermal Characteristics of IGBT

Based on the actual packaging structure of insulated gate bipolar transistor (IGBT) module, this article establishes the power loss model, and analyzes the influence of the position of the lift-off bond wire on the module. Through the theoretical analysis, it is found that the position of the lift-off bond wire is an important factor affecting the aging of the modules. And then the electrothermal coupling model of IGBT is established for simulation, and an experimental platform is built for verification. The results show that the distribution of bond wire lift-off position is one of the characteristics of bond wire failure. When the bond wire lift-off failure is concentrated on a single IGBT chip, it will accelerate the aging process of the modules. Therefore, this article considers that the position of the lift-off bond wire is a significant factor in the aging process of the modules, which should be fully considered in the bond wire state evaluation. In addition, the research results of this article can also provide theoretical reference for the optimization of IGBT module packaging structure.

Panhead accelerations-based methodology for monitoring the stagger in overhead contact line systems

The monitoring of overhead contact lines (OCL) is a key part of railway infrastructure maintenance. This paper proposes a methodology to assess the lateral geometry of contact wire, the so-called stagger, by using the dynamic response of a pantograph. The methodology is tested in a validated virtual environment that resembles the behaviour of the pantograph when it interacts with the OCL. A signal processing is developed to define features relating the lateral position of the contact wire with the vertical acceleration of the contact strip. It is demonstrated that these features have a clear and close connection with the lateral position of the contact wire. Subsequently, model-driven machine learning algorithms are defined using these features to address the OCL stagger prediction and the detection of out-of-range lateral displacement due to a faulty steady-arm. The methodology shows a good prediction performance in the estimation of the stagger amplitude/central position and the steady-arms diagnosis. The prediction of the stagger amplitude is performed with a root-mean-square error of 4.7(10)mm. In addition, the area under the Precision–Recall curve is 0.952 CI95 [0.940, 0.962] for the steady-arms diagnosis.

Heat transfer enhancement of ferrofluid flow in a solar absorber tube under non-uniform magnetic field created by a periodic current-carrying wire

A novel configuration for heat transfer enhancement in parabolic trough solar collector absorbers by the use of a ferrofluid and an external magnetic field generated by a current-carrying wire is analyzed using numerical simulation. This new configuration consists of a wire which varies its position periodically along the tube. The analysis is focused on the study of the thermal hydraulic characteristics, Nusselt number and friction factor, and the average flow patterns in the turbulent flow regime (15·103⩽Re⩽250·103). In addition, different parameters of the periodic wire are analyzed: wire pitch and position angle. Ferrofluid Fe3O4/Therminol 66 is considered for this application. Firstly, the effect of an increase on the magnetic field intensity is studied. The periodic wire configuration shows a higher increment of the Nusselt number in comparison to the straight wire for the same magnetic field increase. The results reveal that the presence of a non-uniform magnetic field generates a disturbed flow with a high velocity region near the current-carrying wire. The periodic wire configuration leads to a spatially-periodic behavior that increases the average Nusselt number and the friction factor, in comparison to a straight wire. Among the studied cases, the position angle θ=30° and the pitch length l=3D are found to provide the maximum Nusselt number (Nu = 244.25 for Re = 15000).

Transcarotid access for remote robotic endovascular neurointerventions: a cadaveric proof-of-concept study.

The purpose of this proof-of-concept study was to demonstrate the setup and feasibility of transcarotid access for remote robotic neurointerventions in a cadaveric model. The interventional procedures were performed in a fresh-frozen cadaveric model using an endovascular robotic system and a robotic angiography imaging system. A prototype remote, robotic-drive system with an ethernet-based network connectivity and audio-video communication system was used to drive the robotic system remotely. After surgical exposure of the common carotid artery in a cadaveric model, an 8-Fr arterial was inserted and anchored. A telescopic guiding sheath and catheter/microcatheter combination was modified to account for the "workable" length with the CorPath GRX robotic system using transcarotid access. To simulate a carotid stenting procedure, a 0.014-inch wire was advanced robotically to the extracranial internal carotid artery. After confirming the wire position and anatomy by angiography, a self-expandable rapid exchange nitinol stent was loaded into the robotic cassette, advanced, and then deployed robotically across the carotid bifurcation. To simulate an endovascular stroke recanalization procedure, a 0.014-inch wire was advanced into the proximal middle cerebral artery with robotic assistance. A modified 2.95-Fr delivery microcatheter (Velocity, Penumbra Inc.) was loaded into the robotic cassette and positioned. After robotic retraction of the wire, it was switched manually to a mechanical thrombectomy device (Solitaire X, Medtronic). The stentriever was then advanced robotically into the end of the microcatheter. After robotic unfolding and short microcatheter retraction, the microcatheter was manually removed and the stent retriever was extracted using robotic assistance. During intravascular navigation, the device position was guided by 2D angiography and confirmed by 3D cone-beam CT angiography. In this proof-of-concept cadaver study, the authors demonstrated the setup and technical feasibility of transcarotid access for remote robot-assisted neurointerventions such as carotid artery stenting and mechanical thrombectomy. Using transcarotid access, catheter length modifications were necessary to achieve "working length" compatibility with the current-generation CorPath GRX robotic system. While further improvements in dedicated robotic solutions for neurointerventions and next-generation thrombectomy devices are necessary, the transcarotid approach provides a direct, relatively rapid access route to the brain for delivering remote stroke treatment.

The Effect of Corona Wire Position and Radius in a Duct-Type ESP with Wavy Collecting Plates

Electrostatic precipitators (ESPs) have become one of the most effective methods for removing harmful particles from various industries. Many investigations in this subject are constantly developing due to the inherent benefits of using an ESP, and there are many robust initiatives taking place today all over the world. Different configurations of collection and discharging electrodes must be investigated to improve the ESP performance of ESPs. Many studies are working to enhance existing models in different ways. The geometry of the electrodes and the collecting plates is one area that could be improved. This paper investigates the wavy designs of collecting electrodes with varied corona electrode radius (range of variable corona radius (0.07-0.6 mm)) and position in a single-stage ESP. Wavy plates (WPs) and Inverted wavy plates (InvWPs) are compared to flat plates (FPs) using a numerical simulation tool. The results of this work show the impact of changing the corona radius when wavy and inverted wavy collecting electrodes are used on the electric potential, electric field strength, current density, and space charge density distribution, and particle collection efficiency. When compared to InvWPs and FPs, WPs show the highest performance in this range of particles. Although InvWPs can be utilized to reduce current density or space charge density, they do not increase particle collection efficiency.

Optimized Neural Network Prediction Model of Shape Memory Alloy and Its Application for Structural Vibration Control.

The traditional mathematical model of shape memory alloy (SMA) is complicated and difficult to program in numerical analysis. The artificial neural network is a nonlinear modeling method which does not depend on the mathematical model and avoids the inevitable error in the traditional modeling method. In this paper, an optimized neural network prediction model of shape memory alloy and its application for structural vibration control are discussed. The superelastic properties of austenitic SMA wires were tested by experiments. The material property test data were taken as the training samples of the BP neural network, and a prediction model optimized by the genetic algorithm was established. By using the improved genetic algorithm, the position and quantity of the SMA wires were optimized in a three-storey spatial structure, and the dynamic response analysis of the optimal arrangement was carried out. The results show that, compared with the unoptimized neural network prediction model of SMA, the optimized prediction model is in better agreement with the test curve and has higher stability, it can well reflect the effect of loading rate on the superelastic properties of SMA, and is a high precision rate-dependent dynamic prediction model. Moreover, the BP network constitutive model is simple to use and convenient for dynamic simulation analysis of an SMA passive control structure. The controlled structure with optimized SMA wires can inhibit the structural seismic responses more effectively. However, it is not the case that the more SMA wires, the better the shock absorption effect. When SMA wires exceed a certain number, the vibration reduction effect gradually decreases. Therefore, the seismic effect can be reduced economically and effectively only when the number and location of SMA wires are properly configured. When four SMA wires are arranged, the acceptable shock absorption effect is obtained, and the sum of the structural storey drift can be reduced by 44.51%.

Software supported robotic PCI in coronary arteries – comparison from the ROBO.pci trial

Abstract Background Robotic percutaneous coronary interventions (rPCI) have proven to be efficient and safe. The robotics software has recently been updated and now allows precise and fully controlled navigation of devices and wires to fit the various morphologic conditions of coronary arteries and calcified segments. Objectives In the present study we aimed to compare the different robotic wiring modalities supported by the new software. Study design rPCI performed using the updated robotics software was compared with rPCI using the manually executed wire positioning. Lesion crossing was performed with each method under identical circumstances, crossing the same lesion and measuring the wire times. Measurements were started at the ostium of the guiding catheter and were stopped at a pre-defined individual coronary anatomical landmark. Results Eleven consecutive patients with 11 lesions were enrolled in this trial. The mean age of patients was 63±6 years with typical cardiovascular comorbidities and 54% (6/11) presented with three-vessel disease. All patients underwent PCI in an elective setting with stable chronic coronary syndrome. The majority of lesions were located in the LCX (45%, 5/11) followed by the LAD (27%, 3/11) and the RCA (27%, 3/11). All lesions were de novo ACC/AHA grade B2/C lesions, and the procedure was performed by experienced (high-volume) interventional cardiologists. The lesion crossing times were not significantly different (manual crossing 15.00 [IQR: 40] sec vs. rPCI without software support 18.00 [IQR: 18] sec vs. rPCI with software support 13.00 [IQR: 47] sec; p=n.s.). Summary rPCI without software support tends to be slower than rPCI with software support. There was no statistical significance. rPCI was found to be safe and feasible and the new software tends to reduced procedural time, which could reduce operators' health risks and improve patients' outcomes. Further randomized controlled trials are needed to evaluate the long-term benefits. Funding Acknowledgement Type of funding sources: None.

ELSO Interim Guidelines for Venoarterial Extracorporeal Membrane Oxygenation in Adult Cardiac Patients.

ELSO Interim Guidelines for Venoarterial Extracorporeal Membrane Oxygenation in Adult Cardiac Patients.

Conceptual design and theoretical analysis of a system: The reference network of alignment

As a fourth-generation light source based on a diffraction-limited storage ring, Hefei Advanced Light Facility (HALF) has higher requirements for the alignment of magnets in terms of accuracy, efficiency and reliability. In this paper, we propose a system called the Reference Network of Alignment (RNA) that can achieve a transverse alignment accuracy of the magnets of ±20μm along a 100 m straight section of the accelerator. We first present the concept underlying the design of the RNA system. The girder assembly on which several common axis magnets are fixed forms the independent unit, and a long stretched wire is used as a straightness reference. A theoretical analysis of our system is then presented based on strict mathematical models that center on the combining method of the wire position sensors, the hydrostatic leveling sensors, and two-axis inclination sensors, for which the positions and orientations are known relative to each other. Finally, we perform a simulation of the RNA system using the Monte Carlo method. The results show that it is credible to assume that the RNA system can achieve an alignment installation accuracy of 20 μm and a displacement monitoring accuracy of 15 μm.

Accuracy analysis of current sensor based on magnetic field

Current is the most important parameter in power system, and its accurate measurement is the basis of system operation. With the research of new current measurement technology based on magnetic field, such as Hall effect and giant magnetoresistance, the current can be measured without contact with the conduct. However, due to the different wire diameters and the deviation of wire position, it is impossible to measure the multi-range current through the sensor with a single structure in practical use. In this paper, the error analysis of current technology based on magnetic field is studied. First, the measurement model is analyzed, and the measured wire current and magnetic field measuring point model is established. Through simulation, the influence of wire diameter and position deviation on the measurement accuracy is tested, which supports the design of current sensor based on magnetic field.

A Novel Tracker-Less, Universal, Image-Based, Computer-Assisted Navigation in Orthopaedic Trauma- A pilot Study.

Computer-assisted navigation system is well-known orthopaedic advancement which allow surgeon to obtain a real-time feedback during surgeries, thus helps to reduce intraoperative errors. Currently used navigation systems are tracker based, invasive and non-universal. Therefore this study was conducted to test novel tracker-less, image-based, non-invasive, universal, real-time navigation system to predict future position of the guide wire, K wire, screws and plates in orthopaedic trauma surgeries. Firstly, the software was tested and validated on bone model. Then utilized for non-randomised comparative study conducted on 81 adult patients with stable intertrochanteric fracture treated by dynamic hip screw and barrel plate fixation. In one group, C-arm was used and in other, software navigation was used in addition to C-arm. Parameters such as time to insertion, number of C-arm shoots and number of attempts for guide wire insertion were documented and compared. Use of the navigation software for guide wire positioning in bone models and in the DHS barrel plate surgery proved to be significantly beneficial as compared to not using navigation. Intraoperative use of this new navigation system eliminates trial and error improving accuracy and reducing the operative time and radiation exposure. Thus this novel trackerless, C-arm image-based navigation system have potential to replace existing tracker-based navigation systems because of its universal nature, noninvasive and more effective properties.