Arc Width Research Articles

A Double-Stator Flux Switching PM Machine With Multi-PM MMF Harmonics

A double stator flux switching permanent-magnet machine (DS-FSPM) is proposed to improve the torque density and power factor of DS-FSPMs. As opposed to regular DS-FSPMs with spoke-PMs of the same pole arc, the pole arcs of the spokePMs in the proposed DS-FSPM are not exactly the same, which can produce multiorder PM magnetic motive force (MMF) working harmonics. Meanwhile, the total PM usage of the regular and the proposed DS-FSPMs is kept identical. In this paper, the working mechanism of the proposed DS-FSPM is introduced, and the effects of several key parameters including PM pole arc, slot-pole combination, split ratio, rotor thickness, and rotor width on torque and power factor are also analyzed.

Spatial and Depth‐Dependent Variations in Magma Volume Addition and Addition Rates to Continental Arcs: Application to Global CO2 Fluxes since 750 Ma

AbstractMagma transfer from the mantle to the crust in arcs is an important step in the global cycling of elements and volatiles from Earth's interior to the atmosphere. Arc intrusive rocks dominate the total magma mass budget over extrusive rocks. However, their total volume and rate of addition is still poorly constrained, especially in continental arcs. We present lateral (forearc to backarc) and depth‐dependent (volcanics to deep crust) magma volume additions and arc‐wide magma addition rates (MARs) calculated from three continental arc crustal sections preserving magma flare‐up periods. We observe an increase in volume addition with depth and less magma added in the forearc (~15%) and backarc (~10% to 30%) compared to the main arc. Crustal‐wide MARs for each section are remarkably similar and around 0.7–0.9 km3/km2/Ma. MARs can be used to estimate CO2 fluxes from continental arcs. With initial magma CO2 contents of 1.5 wt.%, global continental arc lengths, and MARs, we calculate changes in C (Mt/year) released from continental arcs since 750 Ma. Calculated present‐day global C fluxes are similar to values constrained by other methods. Throughout the Phanerozoic, assuming equal durations of flare‐up and lull magmatism, calculated continental CO2 flux rates vary between 4 and 18 Mt C/year with highest values in the Mesozoic. These fluxes are considered minima since the intake of mantle and/or crustal carbon is not considered. Magmatic episodicity in continental arcs and changes in arc thickness and width are critical to consider when calculating MARs through time.

Biomechanics of Long Cane Use.

The modern long cane has been used by people who are blind for traveling for decades. This article describes parameters surrounding the collection of over 10,000 trials of people walking with the long cane to detect drop-offs or obstacles. The data include 10,069 trials representing 101 different participants in 366 conditions over 11 studies spanning the 9 years from 2007 to 2016. Each of the studies investigated different participant or cane characteristics or both in terms of their effect on either drop-off or obstacle detection. Results of detection performance in these studies appear in other articles. This article describes biomechanical measures derived from 3-D motion analysis equipment used during the studies. Initial treatment of the large data set indicated that participants tended to not center their cane arc laterally on their body, deviating up to about 20 centimeters from midline. Arc widths averaged almost a meter, and arcs were generally centered. Participants were generally poor at being in step or having consistent rhythm. Coverage rates averaged about 85%. Although participants might have demonstrated artificially high skill performance due to being in a research study, data do offer insights into mechanical performance of skills. This survey of the data set indicates that not centering the hand holding the cane does not decrease body coverage less than about 85%. However, further analyses will be conducted to delve more deeply into all aspects of the data. Basic cane skills can be taught with short sessions and massed practice. Novices can acquire basic cane skills on par with cane users who are blind, but individual differences exist and the interplay of biomechanical variables needs to more fully understood.

Structural Design of Partitioned Stator Doubly Salient Permanent Magnet Generator for Power Output Improvement

Partitioned stator doubly salient permanent magnet generators (PS-DSPGs) have been extensively used for electrical generation mainly due to their high reliability, high electromotive force (EMF), and high-power output. Therefore, we aim to improve the output power of a PS-DSPG by designing the optimal configuration of generator pole structure. Electrical characteristics including the magnetic flux linkage distribution, phase EMF, cogging torque, voltage regulation, and power output profile were characterized by using the finite element method. After optimizing the generator pole structure including the angle of air gap arc width, it was found that the proposed PS-DSPG with 18/15 (stator/rotor) pole structure with optimized air gap arc width could produce higher EMF of about 23.24% than a conventional structure because this structure has the suitable number of pole structures. Also, an analysis of voltage regulation and power output profiles under the loaded condition were carried out, and it was indicated that the PS-DSPG based on the suitable 18/15-pole structure could provide the best machine performance where the output power is 11.63% higher than the conventional structure. Hence, the proposed PS-DSPG with 18/15-pole structure can appropriately be utilized for electrical generation, especially in low-speed operated generator applications.

Arc discharge and pressure characteristics in pulsed plasma gas of PAW

This paper investigated the arc characteristics in pulsed plasma gas of plasma arc welding using a synchronous image- and electrical signal-acquisition system. The arc sizes (including the arc length L, the arc width on the water-cooling copper plate surface Wa, and the arc width under the nozzle Wc) and arc voltage changed regularly with the plasma gas periodically on/off. And the changing trends of arc sizes were affected by the plasma gas flow rate and the plasma gas switching frequency. The changing scale of arc voltage was proportional to the plasma gas flow rate and was inversely proportional to the plasma gas switching frequency. The average plasma arc welding (PAW) and plasma arc welding with pulsed plasma gas (PPG-PAW) arc voltages were equal when the plasma gas flow rate was the same. The arc pressure also presented cyclical changes during the plasma gas on/off, and the changing scale and the axial mean value were inversely proportional to the plasma gas switching frequency. The periodically oscillating arc and arc pressure would be beneficial to the refinement of grain structure during the welding process.

Custom 3D-printed Total Talar Prostheses Restore Normal Joint Anatomy Throughout the Hindfoot

Category: Hindfoot Introduction/Purpose: Third generation total talar prostheses (TTP) are viable options for talar avascular necrosis (AVN) in the absence of neighboring joint pathology. The use of modern three-dimensional (3D) printing allows for the production of custom implants that exactly mimic the patient’s anatomy. The aim of this study is to determine the accuracy of 3D printing in reproducing a synthetic talus, and in doing so, restoring more normal anatomic relationships. We hypothesize that this mode of replication will restore and maintain normal radiographic alignment of the ankle, subtalar, and forefoot joints in the setting of talar AVN. Methods: A retrospective analysis was performed on all patients undergoing TTP implantation for the treatment of talar AVN between 2016 and 2017. Pertinent demographic and operative factors were recorded. Radiographic measurements were taken pre- and post-operatively to determine native talar dimensions, TTP implant dimensions, and the corresponding radiographic alignment about the forefoot, hindfoot, and ankle. Results: Fourteen patients, treated for AVN between 2016-2017, were identified in our cohort. Talar arc length and width were not found to be significantly changed, however talar height was significantly increased with use of TTP. Five alignment dimensions were measured (tibiotalar alignment, talar tilt angle, Boehler’s angle, talar declination angle, and Meary’s Angle), of which, only talar tilt angle was significantly changed. Instances of Meary’s angle correction were observed in cavus and planus foot deformity. Conclusion: This study represents the largest case series of TTP performed in the United States, and is the first to investigate the 3D printed TTP. As a proof-of-concept, 3D printed TTP was successful in restoring talar height and talar tilt in the setting of AVN. Additionally, the procedure maintained normal alignment in non-pathologic joints. Total talar prosthesis, based on our cohort, is a viable option to restore more normal anatomic alignment.

Arc properties and droplet transfer characteristics in cable-type welding wire electrogas welding

The arc properties and droplet transfer characteristics in cable-type welding wire electrogas welding were studied. A high-speed video camera and an electrical signal acquisition system were used to obtain welding arc images, the droplet transfer process and electrical signals. The results show that with an increase in welding current, the droplet transfer mode changes from globular transfer to projected transfer; the arc length decreases, the arc width increases, and the droplet size decreases. The wire extension, which ranged from 30 mm to 35 mm, has a slight effect on the droplet size, arc length and arc width. During the welding process, the arc migrates from the end of the welding wire to the necking part of the droplet. With the transition of the droplet, the arc migrates to the end of the welding wire again. As the welding current increases, the frequency of arc migration increases, and the formed droplet column becomes shorter. The rotating arc has a strong stirring effect on the molten pool, which promotes the heat transfer between the molten pool and the sidewall.

Custom 3D-Printed Total Talar Prostheses Restore Normal Joint Anatomy Throughout the Hindfoot.

Third generation total talar prostheses (TTPs) are viable options for talar avascular necrosis (AVN) in the absence of neighboring joint pathology. The use of modern three-dimensional (3D) printing allows the production of custom implants that exactly mimic the patient's anatomy. The aim of this study is to determine the accuracy of 3D printing in reproducing a synthetic talus and, in doing so, restoring more normal anatomical relationships. We hypothesize that this mode of replication will restore and maintain normal radiographic alignment of the ankle, subtalar, and forefoot joints in the setting of talar AVN. A retrospective analysis was performed on all patients undergoing TTP implantation for the treatment of talar AVN between 2016 and 2017. Radiographic measurements were taken preoperatively and postoperatively to determine native talar dimensions, TTP implant dimensions, and the corresponding radiographic alignment about the forefoot, hindfoot, and ankle. A total of 14 patients were identified in our cohort. Talar arc length and width were not found to be significantly changed; however, talar height was significantly increased with use of TTP. Five alignment dimensions were measured, of which, only talar tilt angle was significantly changed. Instances of Meary's angle correction were observed in cavus and planus foot deformity. As a proof of concept, 3D-printed TTP was successful in restoring talar height and talar tilt in the setting of AVN. Additionally, the procedure maintained normal alignment in nonpathological joints. TTPs, based on our cohort, are a viable option to restore more normal anatomical alignment. Level IV: Case series.

Effect of cane length and swing arc width on drop-off and obstacle detection with the long cane.

A repeated-measures design with block randomization was used for the study, in which 15 adults with visual impairments attempted to detect the drop-offs and obstacles with the canes of different lengths, swinging the cane in different widths (narrow vs wide). Participants detected the drop-offs significantly more reliably with the standard-length cane (79.5% ± 6.5% of the time) than with the extended-length cane (67.6% ± 9.1%), p <.001. The drop-off detection threshold of the standard-length cane (4.1 ± 1.1 cm) was also significantly smaller than that of the extended-length cane (6.5±1.8cm), p <.001. In addition, participants detected drop-offs at a significantly higher percentage when they swung the cane approximately 3 cm beyond the widest part of the body (78.6% ± 7.6%) than when they swung it substantially wider (30 cm; 68.5% ± 8.3%), p <.001. In contrast, neither cane length (p =.074) nor cane swing arc width (p =.185) had a significant effect on obstacle detection performance. The findings of the study may help orientation and mobility specialists recommend appropriate cane length and cane swing arc width to visually impaired cane users.

Design Improvement of Three Phase 12Slot-14Pole Outer Rotor Field Excitation Flux Switching Motor

This paper present with design improvement of 12Slot-14Pole outer rotor field excitation flux switching motor (ORFEFSM) from the initial design by implement Deterministic Optimization Method (DOM) which involve 2-dimensional Finite-Element Analysis (FEA). The design improvement starts with the non-active part, rotor and followed with active part, stator which involve the armature coil slot and field excitation coil (FEC) slot. Since it is one of local optimization method, this method involves more than one cycle of improvement depends on the design structure and slot-pole configuration until achieve optimum performance. However, the initial torque and power output of 12Slot-14Pole is 112.95 Nm and 50.46 kW. The main objective is to improve the structure in order to obtain optimum torque and power output. Besides, it is necessary to reduce flux saturation and optimize the flux flow between the rotor teeth and stator arc width. The target torque and power output performance is expected higher than 210 Nm and 123 kW. With the deterministic optimization method technique, the final torque and power output achived are 221.83 Nm and 189kW.

Role of mandibular canine in sex determination

Objective: To establish the effectiveness of mandibular canine index in predicting sex in rajasthan population. Materials and Methods: 100 subjects belonging to rajesthan population (50 males; 50 females) in the age group of 17-25 yrs were included. Impressions were made with alginate and study models prepared with dental stone and living subjects Maximum mesiodistal diameter of mandibular canines and the linear distance between tips of mandibular canines were measured using a Vernier caliper. Observed mandibular canine index (MCIo) and standerd MCI was calculated as the ratio between the maximum mesiodistal width of mandibular canine and canine arc width. Results: Left canine exhibited greater sexual dimorphism i.e. 9.05% as compared with right canine i.e. 8.782%. Sex could be predicted correctly in approximately 80% of subjects examined. Conclusion: With the standard MCI it was possible to detect sex in the population of rajesthan to an extent of about 72%. Hence it is considered as a quick, easy and reproducible method for determining the sex of an individual.

Characterization of image quality in digital tomosynthesis for radiotherapy applications

Digital tomosynthesis (DTS) is a reconstruction technique which is used for fast, low dose, volumetric imaging. In this work, we systematically characterize the sensitivity of image quality metrics such as image non-uniformity, spatial resolution, contrast, and HU accuracy against changes in the reconstruction arc spanned by the projection images. Understanding how the choice of reconstruction arc width affects image quality is crucial to both selecting the appropriate technique as well as interpreting the DTS images. DTS images of both computational and physical phantoms were reconstructed with arcs of 10°, 20°, 30°, 40°, 60°, 90°, 180°, and 360°. Our results show that image non-uniformity has a nonlinear improvement with increasing arc width, and the cause of non-uniformity is dominated by artifact. Spatial resolution within a DTS plane was found to be nearly independent of reconstruction arc, and is therefore limited primarily by hardware such as detector pixel dimensions and the effective source size. The spatial resolution between DTS planes (e.g. slice thickness) is a strong function of reconstruction arc, increasing to over 30 mm at very small reconstruction arc widths. The spatial resolution also exhibits a nonlinear sensitivity to changes in the reconstruction arc width, large improvements for small increases in reconstruction arc at low arcs. Image contrast and HU accuracy have a complex dependence on the reconstruction arc width. Interpretation of these metrics is difficult and should not be viewed in a similar manner as with CT or CBCT images. With the unique challenges associated with DTS image interpretation, the most promising radiotherapy application is rigid registration of bony anatomy as it presents high contrast registration landmarks.

Using Physics-Based Models and Redox Shuttles to Investigate the Effects of FEC on Electrode Passivation

Chemical additives, such as fluoroethylene carbonate (FEC), can be used to improve lithium-ion battery performance by facilitating the formation of a passivation layer on the negative electrode surface. We compare passivation layers formed by electrolytes with and without FEC, using the ferrocenium-ferrocene redox couple. To quantify experimental findings, we develop a mathematical planar-electrode impedance model to extract physical parameters related to the passivation layer. Experimental cyclic voltammetry (CV) shows that the electronic passivity of the formed passivation layers is dependent upon the imposed electrochemical conditions. That is, potentiostatic holds cause surface passivation, leading to slower ferrocenium reduction kinetics. With increasing formation time, the high-frequency arc width of the impedance spectra increases for both electrolytes. However, the increase in high-frequency arc width is greater for electrolyte without FEC than that containing FEC. Formation potential influences the magnitude of electronic passivity of the solid electrolyte interphase (SEI), with more negative potentials increasing electronic passivity. In Figure 1(a), the electrode surfaces have been passivated for 30 minutes under a 0.6 V potentiostatic hold. Two CVs are measured at ν = 10 mV s-1, comparing electrolytes with and without FEC. The addition of FEC to the primary electrolyte enhances ferrocenium reduction kinetics, when comparing peak heights and position. Figure 1(b) shows experimental and simulated impedance responses, obtained after 30 minutes of passivation around the redox shuttle equilibrium potential (3.24 V). Experimental and simulated impedance responses show good agreement over the frequency range shown, suggesting that reliable conclusions can be drawn about the SEI. Particularly, impedance response simulations suggest that interfacial kinetics and porosity of the outer layer of the SEI greatly influences the high-frequency arc width. Figure 1

Morphologic Variability of the Shoulder between the Populations of North American and East Asian.

BackgroundThe aim of this study was to determine if there were significant differences in glenohumeral joint morphology between North American and East Asian populations that may influence sizing and selection of shoulder arthroplasty systems.MethodsComputed tomography reconstructions of 92 North American and 58 East Asian patients were used to perform 3-dimensional measurements. The proximal humeral position was normalized in all patients by aligning it with the scapular plane utilizing anatomic landmarks. Measurements were performed on the humerus and scapula and included coronal and axial humeral head radius, humeral neck shaft and articular arc angles, glenoid height and width, and critical shoulder angle. Glenohumeral relationships were also measured and included lateral distance to the greater tuberosity and acromion, abduction lever arm, and acromial index. Parametric and nonparametric statistical analyses were used to compare population metrics.ResultsEast Asian glenohumeral measurements were significantly smaller for all linear metrics (p < 0.05), with the exception of acromial length, which was greater than in the North American cohort (p < 0.001). The increase in acromial length affected all measurements involving the acromion including abduction lever arms. No difference was found between the neck shaft and articular angular measurements.ConclusionsThe East Asian population exhibited smaller shoulder morphometrics than their North American cohort, with the exception of an extended acromial overhang. The morphologic data can provide some additional factors to consider when choosing an optimal shoulder implant for the East Asian population, in addition to creating future designs that may better accommodate this population.

Thermal performance of six different types of wavy-fins

Purpose – Heat transfer inside wavy fins is analyzed in this work. The paper aim to discuss this issue. Design/methodology/approach – Six different types of wavy fins are considered. The fin equation for each fin type is solved using a high accurate finite difference method. Excellent agreement is obtained between the numerical solution under zero wave amplitude and the exact solution of the plain fin. Findings – The following wavy fin types and conditions are found to produce larger heat transfer rate and its volumetric value than those for the plain fin and other wavy fins: short fins with parallel wavy profiles and large surface-wave frequency; long fins with symmetric wavy surface around the length axis, positive cross-sectional area gradient at the base, and large surface-wave frequency; and long fins with symmetric wavy profiles around the length axis, positive cross-sectional area gradient at the base, and small surface-wave frequency. Research limitations/implications – In addition, both fins with symmetric wavy surface around the width axis and parallel wavy surfaces along the width axis have same performance indicators. Also, these wavy fins possess higher fin efficiency than either that of the plain fin or those of the other types of wavy fins. Originality/value – Finally, heat transfer enhancements in the studied wavy fins are increased by increases in the excess of the surface area, cross-sectional area gradient at the base, arc length and arc width relative to those of the plain fin.

Optimal parameter decision method in VMAT for lung tumors with respiratory motions

When performing lung cancer treatments using volumetric modulated arc therapy (VMAT) technique, dose error related to respiratory motion of tumors and multi leaf collimator (MLC) movement may occur. The dose error causes daily dose variation in multiple fractionations irradiation. The purpose of this study is to verify the influence of the respiratory motion and the MLC movement on the daily dose variation, and to confirm the feasibility of deciding robust planning parameter against the dose variation. We prepared 5 VMAT plans for imitating lung tumor in thorax dynamic phantom. Dose calculations of these plans were done taking into account the respiratory motions. We examined the relation between dose variation and two parameters that were number of respiration in an arc and MLC gap width. We presented the relationship between the dose variation and each parameters using regression analysis, and we could derive the approximation formula for estimating the dose variation using these parameters. We could estimate dose variation in another VMAT plans using the approximation formula and another plans parameters. By confirming dose variation in planning procedure using this estimation method, we may decide planning parameter taking the dose variation into account. So, we could establish the estimation method to decide adequate planning parameters in VMAT.

Reduction of cogging torque in dual rotor permanent magnet generator for direct coupled wind energy systems.

In wind energy systems employing permanent magnet generator, there is an imperative need to reduce the cogging torque for smooth and reliable cut in operation. In a permanent magnet generator, cogging torque is produced due to interaction of the rotor magnets with slots and teeth of the stator. This paper is a result of an ongoing research work that deals with various methods to reduce cogging torque in dual rotor radial flux permanent magnet generator (DRFPMG) for direct coupled stand alone wind energy systems (SAWES). Three methods were applied to reduce the cogging torque in DRFPMG. The methods were changing slot opening width, changing magnet pole arc width and shifting of slot openings. A combination of these three methods was applied to reduce the cogging torque to a level suitable for direct coupled SAWES. Both determination and reduction of cogging torque were carried out by finite element analysis (FEA) using MagNet Software. The cogging torque of DRFPMG has been reduced without major change in induced emf. A prototype of 1 kW, 120 rpm DRFPMG was fabricated and tested to validate the simulation results. The test results have good agreement with the simulation predictions.

Role of Mandibular Canines in Sex Determination

Objective: To establish the effectiveness of mandibular canine index in predicting sex in rajasthan population. Materials and Methods: 100 subjects belonging to rajesthan population (50 males; 50 females) in the age group of 17-25 yrs were included. Impressions were made with alginate and study models prepared with dental stone and living subjects Maximum mesiodistal diameter of mandibular canines and the linear distance between tips of mandibular canines were measured using a Vernier caliper. Observed mandibular canine index (MCIo) and standerd MCI was calculated as the ratio between the maximum mesiodistal width of mandibular canine and canine arc width. Results: Left canine exhibited greater sexual dimorphism i.e. 9.05% as compared with right canine i.e. 8.782%. Sex could be predicted correctly in approximately 80% of subjects examined. Conclusion: With the standard MCI it was possible to detect sex in the population of rajesthan to an extent of about 72%. Hence it is considered as a quick, easy and reproducible method for determining the sex of an individual.

A comparative study on the relationship between inter alar width, and inter commissural width on circumferential arc width of maxillary anterior teeth in different age groups.

This study was done to determine the relationship between interalar width and inter commissural width on circumferential arc width of maxillary anterior teeth in dentulous subjects between the age groups of 20-50years. The study involved 300 subjects, in whom measurements were made from the distal aspect of each maxillary canine, across the facial surfaces of the six anterior teeth, using brass wire and a Vernier calliper. Interalar and inter commissural width were recorded after placing two points and measured with a Vernier calliper. Results were statistically analyzed using unpaired t test, Kolmogorov-Smirnov and Pearson's correlation coefficient test. This study confirmed the reliability of interalar width to determine the circumferential arc width which can be used as a reference in edentulous patients.

Research and Application of GPR in Detection of Heating Pipelines on Complex Highway

Based on test principle of ground penetrating radar (GPR), the application feasibility for detecting the heating pipelines on complex highway is verified. In accordance with the complex highway in Wangjing region of Beijing city in China, by using ground penetrating radar of SIR-20 to monitor the geological situation of construction surface, the plain position of pipeline and the buried depth, the detection shows that: the objects of bigger relative dielectric constant absorbs the electromagnetic wave signal from periphery; the maximum intensity of reflection radar wave appears at the top of pipeline; the arc width in radar wave image produced by the bottom of pipeline is bigger than the top. Based on these studies, the design program and accident removal countermeasures for the detection of complex highway pipeline are proposed. Meanwhile, combining with actual measurement in field, contrives scheme utilizing ground penetrating radar to detect heating pipelines. It could be verified the feasibility of testing heating pipelines with ground penetrating radar, provides a basis for the subsequent security dynamic construction design, and accumulates some experience for ground penetrating radar detecting pipeline on complex highway.