Rotational Loss Research Articles

Measurement of alternating and rotational magnetostrictions of Non-oriented silicon steel sheets

Extensive numerical analyses and experimental tests have shown that while major regions of magnetic cores in electromagnetic devices, such as transformers and rotating electric machines, are dominated by the alternating magnetic fields, the rotating magnetic fields exist in the corner joints of multi-phase transformers and the yoke area behind the teeth of rotating electric machines. These magnetic fields cause core losses due to hysteresis and eddy currents, mechanical vibration and acoustic noises due to magnetostriction. Many studies have been reported in the literature on alternating and rotational core losses and alternating magnetostriction, but not so much on rotational magnetostriction, especially in non-oriented (NO) silicon steel sheets. The vibration and noise caused by rotational magnetostriction are much higher than those caused by alternating magnetostriction. This paper reports the development of a magnetostriction measurement system consisting of a 2D symmetrical single sheet tester (SST) and resistance strain gauges. The selection considerations of resistance strain gauges are summarized. The alternating and rotational magnetostriction characteristics of a NO silicon steel, B35A300 (0.35 mm), are measured. Because the rotating magnetic field in the stator is not always ideally circular but more often elliptical, the magnetostriction under elliptical magnetizations with different axis ratios is also measured. The magnetostriction anisotropy of the NO steel sheet is observed and analyzed. The elongation and contraction under alternating, circular and elliptical rotating magnetizations with different axis ratios are discussed. The results can provide data support for calculating and designing multi-phase transformers and rotating electric machines under different types of magnetizations. The research can provide theoretical and practical guidance for mitigating mechanical vibration and acoustic noise caused by magnetostriction.

The liver kinase B1 supports mammary epithelial morphogenesis by inhibiting critical factors that mediate epithelial-mesenchymal transition.

The liver kinase B1 (LKB1) controls cellular metabolism and cell polarity across species. We previously established a mechanism for negative regulation of transforming growth factor β (TGFβ) signaling by LKB1. The impact of this mechanism in the context of epithelial polarity and morphogenesis remains unknown. After demonstrating that human mammary tissue expresses robust LKB1 protein levels, whereas invasive breast cancer exhibits significantly reduced LKB1 levels, we focused on mammary morphogenesis studies in three dimensional(3D) acinar organoids. CRISPR/Cas9-introduced loss-of-function mutations of STK11 (LKB1) led to profound defects in the formation of 3D organoids, resulting in amorphous outgrowth and loss of rotation of young organoids embedded in matrigel. This defect was associated with an enhanced signaling by TGFβ, including TGFβ auto-induction and induction of transcription factors that mediate epithelial-mesenchymal transition (EMT). Protein marker analysis confirmed a more efficient EMT response to TGFβ signaling in LKB1 knockout cells. Accordingly, chemical inhibition of the TGFβ type I receptor kinase largely restored the morphogenetic defect of LKB1 knockout cells. Similarly, chemical inhibition of the bone morphogenetic protein pathway or the TANK-binding kinase 1, or genetic silencing of the EMT factor SNAI1, partially restored the LKB1 knockout defect. Thus, LKB1 sustains mammary epithelial morphogenesis by limiting pathways that promote EMT. The observed downregulation of LKB1 expression in breast cancer is therefore predicted to associate with enhanced EMT induced by SNAI1 and TGFβ family members.

Experimental and Numerical Investigation of the Aerodynamic Ventilation Drag of Heavy-Duty Vehicle Wheels

Due to current EU regulations, constant-speed testing on test tracks is used for aerodynamic certification of heavy-duty vehicles (HDV). However, the aerodynamic development of HDVs is performed using wind tunnels and computational fluid dynamics (CFD). Both techniques commonly neglect the rotational aerodynamic losses of the wheels—the so-called ventilation drag—that are present when driving on the road. This is due to the fact that there is no full-scale wind tunnel for this type of vehicle with a suitable belt system for the simulation of the wheel rotation. Furthermore, the ventilation drag of HDV wheels has been neglected in CFD due to their almost completely closed rim design. These constraints lead to an underprediction of the aerodynamic forces in comparison to the results under on-road conditions when performing constant-speed tests. In order to investigate the ventilation drag of HDV wheels, measurements were carried out on a 1:4.5 scale generic tractor-trailer model in the Model Scale Wind Tunnel of the University of Stuttgart. The measured aerodynamic forces as well as the measured flow field data provide the basis for the definition and validation of a procedure for analyzing the ventilation drag in CFD. Accordingly, the ventilation drag of a full scale HDV was investigated in CFD. The results show that the tire treading and rim geometry have a significant influence on ventilation drag that contributes to the total aerodynamic drag of the HDV. The present work shows that the ventilation drag has a relevant impact on the total aerodynamic drag of HDVs and should therefore not be neglected. The presented CFD approach thus allows to assess the aerodynamic drag under real on-road conditions in an early stage of the vehicle development.

Research on Motor Rotor Loss of High-Speed Air Compressor in the Application of Hydrogen Fuel Cell Vehicle

As an important component of hydrogen fuel cell vehicles, the air compressor with an air foil bearing rotates at tens of thousands of revolutions per minute. The heat generation concentration problem caused by the high-speed motor loss seriously affects the safe and normal operation of the motor, so it is very important to clarify the loss distribution of the high-speed motor and adopt a targeted loss reduction design for air compressor heat dissipation. In this paper, for an air compressor with a foil bearing with a rated speed of 80,000 rpm, an empirical formula and a three-dimensional transient magnetic field finite element model are used to model and calculate the air friction loss, stator core loss, winding loss and permanent magnet eddy current loss. The accuracy of the analytical calculation method is verified by torque test experiments under different revolutions, and the average simulation accuracy can reach 91.1%. Then, the distribution of the air friction loss, stator core loss, winding loss and eddy current loss of the air compressor motor at different revolutions is obtained by using this method. The results show that the proposed method can effectively calculate the motor rotor loss of a high-speed air compressor with air foil bearing. Although the motor efficiency increases with the increase in motor speed, the absolute value of loss also increases with the increase in motor speed. Stator core loss and air friction loss are the main sources of loss, accounting for 55.64% and 29% of the total motor loss, respectively. The electromagnetic loss of winding, the eddy current and other alloys account for a relatively small proportion, which is 15% in total. The conclusions obtained in this paper can effectively guide calculations of motor loss the motor heat dissipation design of a high-speed air compressor with an air foil bearing.

Abstract TP208: A Novel Rat Model Of Vascular Parkinsonism Using The Vasoconstrictor Endothelin-1

Background: Vascular parkinsonism (VP) results from one or more small strokes in the basal ganglia. Patients with vascular parkinsonism usually are unaware of the individual strokes that occur, until progressive motor symptoms gradually appear. While Parkinson’s Disease (PD) and VP share some common symptoms, patients with VP show clear evidence of cerebrovascular disease, are likely to be older, more likely to present with gait difficulty rather than tremor, and less likely to respond to the use of levodopa compared with patients with PD. There is currently no clinically effective treatment for this condition and no rodent model established in the field to study VP. Methods: To stimulate the onset of VP, male Sprague Dawley rats (10-12 mos) were injected with the vasoconstrictor endothelin-1 (ET-1) into the dorsolateral striatum (DLS) or sham operation. Adhesive-tape removal test (ART) was used to test sensory-motor function at 2- and 5- days post DLS stroke and brains were removed and stained with TTC to assess the location of the infarct. In another set, animals were tested for apomorphine-induced rotational behavior at 21-28 days, in conjunction with immunohistochemistry to assess dopamine loss in the substantia nigra pars compacta. Results: We observed a discrete infarct localized to the DLS in animals injected with ET-1. There was no difference in latency to remove the tape in ART outcomes of ET-1 injected animals at 2- and 5- day post ischemia when compared to sham, consistent the fact that these coordinates resulted in a discrete striatal infarction, rather than a cortico-striatal infarction, which is seen in the ET1-induced middle cerebral artery stroke model in rats. At 21- and 28- days post, there was minimal rotational behavior and minimal loss of tyrosine hydroxylase (TH)-positive cells in the lesioned hemisphere, unlike that of the 6-OHDA model of PD, where rapid changes are seen in rotational behavior and loss of TH-positive cells. Conclusions: These data suggest that ET-1-mediated ischemia into the DLS is a promising model for the slow progression of dopaminergic loss and motor deficits reminiscent to that seen in VP patients. Apomorphine induced rotations and TH immunohistochemistry will be evaluated at 30-, 60- and 90- day timepoints.

SCRDet++: Detecting Small, Cluttered and Rotated Objects via Instance-Level Feature Denoising and Rotation Loss Smoothing.

Small and cluttered objects are common in real-world which are challenging for detection. The difficulty is further pronounced when the objects are rotated, as traditional detectors often routinely locate the objects in horizontal bounding box such that the region of interest is contaminated with background or nearby interleaved objects. In this paper, we first innovatively introduce the idea of denoising to object detection. Instance-level denoising on the feature map is performed to enhance the detection to small and cluttered objects. To handle the rotation variation, we also add a novel IoU constant factor to the smooth L1 loss to address the long standing boundary problem, which to our analysis, is mainly caused by the periodicity of angular (PoA) and exchangeability of edges (EoE). By combing these two features, our proposed detector is termed as SCRDet++. Extensive experiments are performed on large aerial images public datasets DOTA, DIOR, UCAS-AOD as well as natural image dataset COCO, scene text dataset ICDAR2015, small traffic light dataset BSTLD and our released S 2 TLD by this paper. The results show the effectiveness of our approach. The released dataset S 2 TLD is made public available, which contains 5,786 images with 14,130 traffic light instances across five categories.

Evidence for an abundant old population of Galactic ultra-long period magnetars and implications for fast radio bursts

ABSTRACT Two recent discoveries, namely PSR J0901−4046 and GLEAM-X J162759.5−523504.3 (hereafter GLEAM-X J1627), have corroborated an extant population of radio-loud periodic sources with long periods (76 and 1091 s, respectively) whose emission can hardly be explained by rotation losses. We argue that GLEAM-X J1627 is a highly magnetized object consistent with a magnetar (an ultra-long period magnetar, ULPM), and demonstrate it is unlikely to be either a magnetically or a rotationally powered white dwarf. By studying these sources together with previously detected objects, we find there are at least a handful of promising candidates for Galactic ULPMs. The detections of these objects imply a substantial number, N ≳ 13 000 and N ≳ 500 for PSR J0901−4046 like and GLEAM-X J1627 like objects, respectively, within our Galaxy. These source densities, as well as cooling age limits from non-detection of thermal X-rays, Galactic offsets, timing stability and dipole spin-down limits, all imply the ULPM candidates are substantially older than confirmed Galactic magnetars and that their formation channel is a common one. Their existence implies widespread survival of magnetar-like fields for several Myr, distinct from the inferred behaviour in confirmed Galactic magnetars. ULPMs may also constitute a second class of FRB progenitors which could naturally exhibit very long periodic activity windows. Finally, we show that existing radio campaigns are biased against detecting objects like these and discuss strategies for future radio and X-ray surveys to identify more such objects. We estimate that ${\cal O}(100)$ more such objects should be detected with SKA-MID and DSA-2000.

Rotor Loss Analysis of an External Rotor High‐Speed Permanent Magnet Motor Considering Current Harmonics and Thermal Analysis under High‐Temperature Gas

AbstractThis paper presents a strategy for direct‐driving a turbine with an external rotor high‐speed permanent magnet motor. It is used to improve the large footprint, low efficiency, high maintenance costs, and high vibration risk of turbines. Combining the characteristics of the working conditions of pipeline gas transmission, this paper takes a 200 kW, 10 000 rpm external rotor high‐speed permanent magnet motor as an example. This paper analyzes the eddy current losses in the rotor due to the armature magnetomotive force generated by the stator fundamental and harmonic currents. To reduce eddy current losses in permanent magnets, a circumferentially segmented pole structure is proposed for theoretical comparison and FEA with common surface‐mounted pole structures under different loads and work angles. The results confirm that the circumferentially segmented pole can effectively reduce the eddy current loss of the permanent magnet rotor. The effect of variations in the pole arc coefficient on eddy current losses in permanent magnets is also analyzed. Finally, the temperature field simulation of the motor is carried out under consideration of wind mill losses. By setting up three comparison groups with different conditions, this paper analyses the influence of the temperature and flow rate of the gas on the temperature rise and heat dissipation of the motor in a high‐temperature gas environment. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

Conceptual design, AC loss calculation, and optimization of an airborne fully high temperature superconducting generator

With the trend of multi-electrification and hybrid-electrification of aircraft, the airborne high temperature superconducting (HTS) generator is considered as the key technology of the new generation of aviation power generation system and has received wide attention. The high critical current and low loss of superconductors can significantly improve the output power, power density, efficiency and other performance of generators. In this work, conceptual design of a fully HTS generator for aircraft is carried out to address key issues in terms of AC loss distribution, which serves as the ground of cryogenic design in the future. A 10 MW fully superconducting generator is designed to be used in a large passenger aircraft (with more than 150 seats and a maximum takeoff weight of about 100 tons). Based on the finite element method (FEM) with the so-called T-A formulation, the electromagnetic characteristics of the generator are analyzed, and AC losses of the stator and rotor are calculated. To calculate the rotor loss in realistic dynamic-field environment, a technique named “rotation-domain exchange” is developed and implemented. By using such technique, accurate calculation of AC loss of the rotor in realistic dynamic electromagnetic environment is achieved with no need of simplified boundary condition as previously reported work. Based on the model, the stator coil structure is optimized to reduce the AC loss and the rotor coil structure is optimized to reduce the HTS tape usage. Results show that the optimized stator AC loss is 15.645 kW, and the rotor AC loss is 6.268 kW, indicating that the rotor AC loss of a fully superconducting generator with narrow air gap and large number of coil turns is not neglectable as previous work assumed. Thus, precise calculation and dedicated optimization of the rotor loss is critical since cooling of the rotor is much more challenging than the stator as the former remains in motion.

Simultaneous Planning and Execution for Safe Flight of Quadrotors suffering One Rotor Loss and Disturbance

Safety is crucial for quadrotor flight, especially when the system suffers one rotor loss and disturbance. To enable quadrotors to survive in these worst cases, this paper proposes a Simultaneous Planning And Execution (SPAE) system strategy. First, the Euler angles under different equilibrium states are solved to ensure the feasibility of the control input when the quadrotors encounters rotor loss and disturbance. Based on the admissible Euler angle solutions, an emergency control strategy is proposed to realize desired angles by recalculating the desired trajectory and the disturbance observer. Meanwhile, this control strategy sacrifices the yaw angle control to handle further underactuation of the system caused by complete rotor failure. In addition to rotor losses, unsafe flight caused by actuator saturation is considered in the SPAE strategy where the planning and execution are simultaneous. As a decision maker, the planning considers the current disturbances and constraints of actuators, then generates a feasible trajectory for controller execution. As an executor of the decision, the controller feedback estimated disturbance information to the trajectory planning, which can help trajectory planning make admissible decisions consistent with the current situation. As a result, the actuator saturation caused by the underestimation of disturbance can be avoided under a feasible regenerated trajectory. Extensive simulations and experiments prove the validity of the proposed SPAE strategy.

Combined latissimus dorsi transfer and deltoid flap for irreparable rotator cuff tear: A retrospective analysis.

This study will evaluate the outcomes of the combined latissimus dorsi tendon transfer and deltoid flap for the management of irreparable posterosuperior rotator cuff tears. This is a retrospective study of 15 patients who have undergone double transfer surgery for their irreparable posterosuperior rotator cuff tears. These patients were followed up in three periods. Functional outcomes such as the constant score (CS), subjective shoulder value (SSV), and range of motion were assessed as well as radiographic outcomes such as the acromio-humeral distance. Fifteen patients were included in the early and intermediate follow-up while only 8 remained at the latest follow-up. At the early follow-up the SSV (p=0.001), CS (p=0.021), and A-H distance (p=0.008) showed a statistically significant improvement from their pre-operative values. At the latest follow-up, only the external rotation decreased from its value at the intermediate follow-up (p=0.027). The double transfer technique showed sustainable improvement of the functional outcomes except for the external rotation. However, the loss of external rotation did not affect the remaining outcomes. Trials comparing this technique to other surgical managements or MIRCTs are needed to confirm these results.

Modulation of non-adiabatic alignment of N<sub>2</sub> molecule by femtosecond laser pulses

The alignment of molecules in the femtosecond laser field induces the refractive index of the propagation medium to change, resulting in the spectral modulation effect. In this paper, the time evolution of the wavelength offset of a probe laser pulse under the influence of the non-adiabatic molecular alignment and Kerr effect is measured experimentally by the pump-probe method in nitrogen medium, and the alignment degree of N<sub>2</sub> molecules is obtained. By solving the time-dependent Schrödinger equation theoretically, the expression of the degree of molecular non-adiabatic alignment is obtained, and the time evolution of non-adiabatic alignment of N<sub>2</sub> molecules is calculated. Taking into account the combined influence of the non-adiabatic molecular alignment and Kerr effect on the change of refractive index of the propagation medium, the modulation effect of birefringence on the spectrum of the probe pulse is achieved. The experimental result accords well with the theoretical calculation, demonstrating that the spectral modulation results obtained by experimental measurement can be used to characterize the alignment degree. Further, the double pulse pump method is used to control the degree of molecular alignment. It is found that the degree of molecular alignment can be enhanced by the double pulse pump method. Moreover, by adjusting the delay time between the two pump laser pulses, that is, adding the second pump laser pulse at one rotational period and half rotational period, respectively, the enhancement and loss of the alignment of N<sub>2</sub> molecules can be achieved, which is named the “alignment switch” effect. The molecular alignment control induced by the double pulse pump method can also be applied to the other molecular systems with different alignment and anti-alignment times, such as CO<sub>2</sub> molecules and O<sub>2</sub> molecules, indicating that the double pulse pump method can be used universally.

Comparative Study of Yokeless Stator Axial-Flux PM Machines Having Fractional Slot Concentrated and Integral Slot Distributed Windings for Electric Vehicle Traction Applications

Due to the high-power density and compact structure, axial-flux permanent magnet (AFPM) machines have gradually received much attention with a view to researching breakthroughs in the next generation electric drive technology for electric vehicles in the recent decades. The AFPM machines with factional slot concentrated winding (FSCW) and yokeless stator, namely yokeless, and segmented armature (YASA) motors, have drawn much attention for its high-power density and potential manufacturability due to the concentrated winding and modular stator core configuration. However, the significant rotor loss resulting from the abundant armature reaction harmonics in FSCW machines imposes a great challenge to the rotor heat dissipation, especially when the pursuit of higher speed has become the trend for electric vehicle applications. On the other hand, distributed winding is widely used in high speed radial flux permanent magnet (PM) machines due to its low armature reaction harmonics. In order to figure out the advantages and disadvantages of various winding arrangement and rotor configuration of AFPM for electric vehicle applications, the comparative study of four AFPM machines with various winding configurations and rotor PM arrangements are comprehensively conducted in this article. First, the design and primary optimization of the four AFPM machines are conducted for the electric vehicle requirement specifications. Then, a comprehensive three-dimensional finite-element analysis (FEA) is employed to compare the electromagnetic performance including torque/power density, efficiency, and flux-weakening capacity. Furthermore, the guideline of winding selection of AFPM machines for electrical vehicle is given. Finally, a yokeless stator AFPM prototype with ISDW configuration is manufactured and tested to verify the validity of the FEA results, as well as confirm the comparison conclusion.

Investigation of Rotational Magnetization Under Non-Sinusoidal Excitation for Non-Oriented Material

Rotational loss forms a significant portion of total core losses in electrical machines. The influence of harmonics on the behavior of magnetic materials is inevitable as these machines are mostly supplied by power electronic converters. Minor loops in hysteresis curves due to harmonics lead to additional losses. While the case of alternating induction (1-D magnetization) with harmonics is thoroughly considered in the literature, the assessment of the effect of rotational magnetization (2-D magnetization) has not yet been done adequately. A qualitative evaluation of rotational hysteresis loops in the presence of minor loops is carried out. The impact of minor loops in the evolution of hysteresis loops under rotating fields is examined. A peculiar behavior of interleaving of hysteresis loops under rotational magnetization is observed, which will affect the total core loss. This analysis can be used to visualize flux patterns on account of rotational magnetization and to accurately predict the performance of a machine during its predesign stage.

The Long-Term Results Of Suture And Graft Techniques Used To Increase Tip Projection and Rotation In Open Technique Septorhinoplasty

Background: In this study, we aimed to evaluate the long-term results of suture and graft techniques used to increase tip projection and rotation in Open Technique Septorhinoplasty.
 Methods: In this study, the data of 89 patients who underwent Open Technique Septorhinoplasty were analysed retrospectively. The patients were divided into groups 1,2,3,4 and 5 according to the suture and graft techniques used. Preoperative and postoperative photographs of all patients included in the study at the 1st, 3rd, 6th, 12th, 36th and 60th months were analyzed. To measure and compare these techniques, tip projection and rotation losses were measured on all photographs using a computer program called Imagej.
 Results: A statistically significant increase was found between the preoperative mean Nasolabial Angle (NLA), Type Angle (TA), Byrd–Hobar Method (BHM) and Nasofacial Angle (NFsA) measurement values and the measurement values at 36th months postoperatively in Groups 1 and 4 (p < 0.05). In Group 2, a statistically significant increase was found between preoperative mean NLA, TA and BHM measurement values and postoperative 36th month measurement values (p < 0.05). In group 1 only, there was a statistically significant difference between the preoperative mean TA, BHM, Simons Method (SM), Goode Method (GM) and Powell-Modified Baum Method (PMBM) measurement values and the postoperative measurement values at 60th months (p < 0.05).
 Conclusions: Our results showed that suture techniques were more effective on projection and rotation than graft techniques in the long term.

Optimizing phosphate fertilizer input to reduce phosphorus loss in rice-oilseed rape rotation.

Identifying the major sources and critical periods of P loss from agricultural fields provides important guidance for reducing P loss. A rice-oilseed rape rotation with no P fertilization (NP, control), medium P fertilization (MP, 90kg P2O5 ha-1 season-1), and high P fertilization (HP, 180kg P2O5 ha-1 season-1) was conducted from 2019 to 2021 in the middle Yangtze River Basin. Runoff and leaching P losses were measured simultaneously using runoff event monitoring and a percolation device. Applying P fertilizer increased the P concentration in the field ponding water and percolation water of the rice-oilseed rape rotation. During the rice growing season, total P (TP), dissolved P (DP), and particulate P (PP) concentrations in the field ponding water and percolation water peaked 1day after P was applied, and then decreased rapidly. After 10days of fertilization, P concentration in the field ponding water of the MP treatment decreased to a minimum and stabilized, while the HP treatment extended this period to 20days. The highest P concentration in percolation water was observed at the first sampling during the oilseed rape season, and then it continued to decrease. Inputting P fertilizer increased P loss by 55.0-109.9% compared to the NP treatment, with annual P losses of 0.89-1.10kg P ha-1, of which runoff loss accounted for 61.7-62.9%. Fertilization and precipitation resulted in varied P loss within and between seasons. Runoff from heavy precipitation during the rice season was the main source of P loss, while PP accounted for 54.7-77.6% of runoff P loss. The strong utilization of soil P by rice resulted in a lower demand for exogenous P fertilizer than oilseed rape. Excessive P input increased the soil P surplus and vertical migration. Therefore, reducing rice season P fertilizer inputs to achieve annual P balance in rice-oilseed rape rotation can effectively reduce soil P surplus and loss while ensuring crop P demand, and the initial 10 d after fertilization in the rice season was a critical period for reducing P runoff loss.

A Novel High-Speed Permanent Magnet Synchronous Motor for Hydrogen Recirculation Side Channel Pumps in Fuel Cell Systems

In hydrogen recirculation side channel pumps, the motor rotor is exposed to a high-pressure mixture of steam and hydrogen, which makes hydrogen embrittlement occur in permanent magnets (PMs). A protective coating is necessary for the PMs in high-pressure hydrogen. However, in the process of sleeve interference installation, the protective coating of the PMs is easily damaged. This paper proposes two surface-mounted insert permanent magnet (SIPM) synchronous motor topologies, SIPM1 and SIPM2, in which the retaining sleeves can be eliminated and the PM protective coating is safe in the assembling process. A dovetail PM and rotor core structure is used to protect the PM with higher rotor strength without retaining the sleeve. The electromagnetic performance of the motors with different rotors, including airgap flux density, output torque, torque ripple, and energy efficiency is compared and optimized. It is concluded that the output torque of the SIPM motor can be promoted by 22.4% and torque ripple can be reduced by 2.9%, while the PM volume remains the same as that of the conventional SPM motor. At the same time, the SIPM motor can have lower harmonic contents of back electromotive force (EMF) and rotor loss compared to the SPM motor with a retaining sleeve. Furthermore, the stress of the PM is analyzed under conditions of PM glue action and failure. The proposed SIPM2 has the ability to operate safely at high-speed and high-temperature operating conditions when the PM glue fails.

Latissimus Dorsi Transfer Combined with Subacromial Balloon Spacer for Bidirectional Rotator Cuff Deficiency

Patients with massive, irreparable rotator cuff tears represent a challenge for treatment, particularly those with loss of external rotation and active elevation. In the cases of glenohumeral arthropathy, reverse shoulder arthroplasty combined with transfer of the latissimus dorsi and teres major tendons has improved active external rotation and overall patient outcomes. However, the reverse shoulder prosthesis could be better used as a second-line treatment in patients without arthropathy. Several joint-preserving surgical approaches have been described for irreparable cuff tears with no substantial differences in results. Although latissimus dorsi transfer has shown long-term clinical reliability and improved functional shoulder function in relatively young patients, isolated tendon transfer appears insufficient to restore range of motion in patients with a bidirectional deficit. The subacromial balloon spacer is an additional new treatment option. This surgical procedure describes an arthroscopic-assisted transfer of the latissimus dorsi tendon followed by the implantation of the subacromial balloon. This combination potentially addresses the bidirectional deficiency by restoring the shoulder external rotational coupling, improving the deltoid load, centering the humeral head, and protecting the transferred tendon from the subacromial compression stresses.

Upper-bound solutions for inclined capacity of suction caissons in a trenched seabed

Large seabed trenches have recently been found adjacent to suction caissons with taut and semi-taut moorings. Seabed trenching leads to loss of soil support and additional caisson rotation, and can therefore significantly decrease geotechnical capacity. In this paper, upper-bound solutions are presented that enable calculation of the reduction in ultimate load-carrying capacity of a suction caisson in a trenched seabed compared to optimal capacity in an intact seabed. Failure mechanisms for caissons embedded in an intact seabed are augmented to incorporate a kinematically admissible mechanism for a trench extending from the mudline. The rate of work dissipation is calculated to determine the optimised solution of the inclined capacity of suction caissons. Comparisons of the results of the upper-bound solutions with finite-element analyses show that the failure mechanisms and the calculated load-carrying capacities derived from the two methods agree well. Therefore, the analytical upper-bound method presented in this paper can be employed for efficient routine calculations of suction caisson capacity under inclined load considering seabed trenches, which are increasingly encountered in engineering practice.

Rotor Loss and Temperature Field of Synchronous Condenser Under Single-Phase Short-Circuit Fault Affected by Different Materials of Rotor Slot Wedge

A synchronous condenser (SC) can provide the dynamic reactive power for the ultra-high-voltage direct current converter station during the system voltage drop caused by the single-phase short-circuit fault, which is one of the prevalent faults. However, the single-phase short-circuit fault can also result in the increase of the rotor loss and temperature and thus restrict the transient operating ability of the SC. A key factor that affects the rotor loss and temperature rise is the material of the rotor slot wedges. For a 300-MVar SC with the rotor slot wedges made of the aluminum, beryllium bronze, and stainless steel, the rotor loss and temperature distribution under the single-phase short-circuit are calculated by coupling the electromagnetic and temperature field models of the SC with the models of the power grid. The variations of the rotor losses along with the rotor slot wedge conductivity are revealed. The rotor regions, where the highest temperature rise appears, are obtained. According to the maximum permissible temperature of the rotor material, the transient operating ability of the SC withstanding the single-phase short-circuit fault is obtained. This article can provide the theoretic basis for improving the transient operating ability of the SC.