A new method to identify rotor–stator rubbing positions based on intrinsic time scale decomposition

To effectively identify the rotor–stator rubbing positions in aero-engine, the paper has proposed the combination of intrinsic time-scale decomposition (ITD) and classification algorithm. Regarding that with larger noise component in proper rotation component (PRC) signals after ITD, it will be more difficult to extract the characteristic information of rubbing faults, the PRC correspondings to the largest noise was eliminated. Meanwhile, signals were reconstructed based on residual proper rotation components, and positions of rubbing faults were identified according to the reconstructed signal. As rubbing extent and other factors cannot be completely the same in each rubbing, energy of reconstructed signal has been normalized to reduce the difference. Normalized energy indexes were inputted into classification algorithm as feature vectors to identify the positions of rubbing faults. To identify the superiority of approach, a comparison has been made between the proposed approach and the method of directly extracting normalized energy indexes of acceleration signals. The result of comparison shows that the two methods both work well in the identification rate of training and test samples; as for the identification rate for an unknown sample, the proposed method is superior to the other, with identification rate increasing by 17% and 9.4%.

Reduced Movement Variability and Kinematics Changes During a Hand to Head Movement are Associated with Improved Outcome Following Superior Capsular Reconstruction (232)

Objectives: Patients with irreparable rotator cuff tears (RCT) exhibit functional limitations including limited ability to perform functional tasks such as combing their hair. One viable treatment is superior capsular reconstruction (SCR). SCR has been shown to restore stability of the glenohumeral (GH) joint in cadavers1, but its effect on in vivo scapular and humeral motion is unknown. The aims of this study were to determine the effect of SCR on in vivo scapular and humeral kinematics during a functional hand to head motion and to identify associations between shoulder kinematics and patient-reported outcomes (PROs). We hypothesized that moving the hand to the back of the head would be accomplished by using more GH based movement including rotation and abduction, and less scapular motion after SCR, and there would be a positive correlation between kinematics changes and improved PROs. Methods: Ten patients (8M, 2F, age 63 ± 7 years) with irreparable RCT provided informed consent to participate in this prospective IRB-approved study. American Shoulder and Elbow Surgeon (ASES), Disability of the Arm Shoulder and Hand (DASH), and Western Ontario Rotator Cuff Index (WORC) surveys were completed before (PRE) and 1-year (1YR-POST) after SCR. Participants were seated and instructed to move their hand from their lap to the back of their head while synchronized biplane radiographs of the shoulder were collected PRE and 1YR-POST at 50 images/s for 3 separate trials. Six degree of freedom GH and scapular kinematics were determined with sub-millimeter accuracy by matching subject-specific CT-based bone models of the humerus and scapula to the synchronized radiographs using a validated volumetric tracking technique3. The contributions of humeral abduction, plane of elevation and internal/external (I/E) rotation relative to the scapula, as well as scapular upward rotation, protraction, and tilt, were calculated for each subject before and after SCR. Differences in rotational contributions from PRE to POST were evaluated using a paired t-test. Variability in rotational contributions was characterized by the inter-subject standard deviation in rotational component contributions to the movement. Correlations among changes in the contribution of each rotation component and between the contribution of each rotation component and PROs were evaluated with Pearson’s correlation coefficients. Significance was set at p < 0.05 for all tests. Results: No differences in contribution to motion were identified in any of the rotational components from PRE to POST (all p > 0.15, Figure 1). Inter-subject variability in rotational contributions to the movement decreased in 5 of the 6 rotational components from PRE to 1YR-POST (Table 1; Figure 1). The PRE to 1YR POST change in contribution from GH abduction was positively correlated to the change in contribution from GH I/E rotation (Figure 2, R = 0.8, p = 0.001) and negatively correlated to the change in contribution from scapular protraction (Figure 2, R = -0.94, p = 0.001). ASES scores were negatively correlated with abduction contribution PRE (R = -0.65, p = 0.043), and positively correlated with plane of elevation PRE (R = 0.685, p = 0.03). Changes in the plane of elevation contribution were also positively correlated with changes in ASES scores (R = 0.635, p = 0.048). Conclusions: This is the first study to report GH and scapular kinematics when performing the functional task of placing the hand to the back of the head. Changes in contributions to the motion were inconsistent across subjects, making it difficult to find differences from PRE to POST. However, inter-subject variation was reduced following surgery, suggesting the participants’ movement strategy converged toward a more similar and possibly more efficient movement pattern following SCR. Increased contributions of glenohumeral rotation and abduction were offset by decreased scapular protraction and indicates SCR affects the contributions from these three rotations, partially supporting our first hypothesis. In addition, increased GH plane of elevation contribution following surgery was associated with improved ASES scores supporting our second hypothesis. This may be consistent with improved glenohumeral kinematics and efficiency of movement during a functional task following SCR. Future work will investigate GH and scapular kinematics in healthy individuals performing the hand to head movement to determine if movement strategy is closer to healthy after SCR.

SS 433 Optical Flares: A New Analysis Reveals Their Origin in L2 Overflow Episodes

The microquasar SS 433 exhibits in Hα intermittent flares. A sequence of observations made in 2004 showed flaring Doppler shifted to both the red and the blue simultaneously. The mean shifts varied from day to day, following the orbital phase of the compact object. At the time, this behaviour was interpreted as indicating an origin in the outer rim of the accretion disk. A new analysis of these old data, presented in this paper, shows that the flares are not eclipsed by the Companion that eclipses the photosphere surrounding the compact object. They are therefore not intermittent sightings of an accretion disk. The alternative explanation is plasma expelled through the L2 point, following the phase of the orbit as it invades the space beyond the system. That space has been mapped with comparatively recent GRAVITY observations of a similar flare in Brγ, indeed revealing a strong rotation component.

Efficient Estimator of Rotor Temperature Designing for Electric and Hybrid Powertrain Platform

This paper presents an efficient method of estimation of rotor cage temperature for induction machine design, applied for electric and hybrid vehicles. This factor influences the torque produced by the induction machine with a field-oriented control algorithm. Equipping sensors to measure the temperature of a rotation component is expensive and is not representative of mass production. The approach of estimation of rotor cage temperature is based on the good knowledge of motor parameters and the estimation of the flux of the machine. For an accuracy inductance taking account of the saturation, the no-load test can be performed. The machine flux will be estimated taking account of the voltage drop of the system on the test-bench. The rapid prototyping in a real-time motor control platform will be presented that integrates this estimator of rotor temperature. We finally show the experimental testing results compared to the measurement of the rotor cage on a prototype asynchronous low-cost motor designing for battery electric city cars.

PO 18074 - Rotational biplanar Chevron osteotomy

Introduction: The Chevron osteotomy is a reliable and popular osteotomy for treating hallux valgus worldwide. Many modifications have been described, but none of them address the rotational deformity of the first metatarsal. The objective of this study is to describe a variation of biplanar Chevron osteotomy that can address first metatarsal rotation when necessary. Methods: The indications for the Rotational Biplanar Chevron Osteotomy (RBCO) are mild to moderate hallux valgus deformity associated with hallux pronation related to internal rotation of the first metatarsal bone. We describe a technique that uses a medial-based wedge parallel to the plantar limb of the osteotomy to free the distal fragment for correct rotation. Results: The more recent concern about hallux valgus surgery represents a very interesting concept that this deformity truly occurs in three different planes, and we may have mistreated the rotation component using current techniques. Many authors have revisited numerous common techniques to adapt them to correct metatarsal pronation. To the best of our knowledge, this is the first paper to describe a modification of the Chevron osteotomy to address rotation of the first metatarsal. Conclusion: We can conclude that rotational biplanar Chevron osteotomy is an useful tool in the treatment of mild hallux valgus associated with metatarsal pronation.

Design of Four-, Six-, and Eight-Bar Linkages for Rectilinear Movement

This paper examines the results of synthesis algorithms for four-, six-, and eight-bar linkages for rectilinear movement. Rectilinear movement is useful for applications such as suspensions that provide linear movement with out a rotation component. The algorithm yields one four-bar, seven six-bar, and 32 eight-bar linkages. The synthesis strategy begins with a task guided by a multi-degree of freedom chain. The algorithm computes constraints to guide the required movement with one degree-of-freedom. Each computed design is analyzed to ensure smooth movement through the specified set of task positions. Finally, we identify the design that has the least variation from a pure rectilinear movement.

Research on Dynamic Balance Adjustment Method of Single Braced Frame Gyroscope Rotor

The uneven mass distribution of gyro rotors results in vibration, rotation and drift of gyro rotors, which seriously affect the performance index and life of gyro rotors. However, because there is no rigid connection between the rotary shaft and the shell of the gyro rotor, the dynamic balancing machine can only balance the vibration component of the single braced frame gyroscope rotor, and can’t measure the gyro rotor’s rotation component. By analyzing the influence of uneven rotor mass distribution on the gyro rotor performance, a method of eliminating two rotational degrees of freedom of the gimbal in gyro rotor by mandrel is proposed, which makes the dynamic balancing machine directly measure the vibration component and the moving component of the gyroscope rotor, and simplifies the dynamic balancing debugging process.

FEATURES OF IMAGING FINDINGS IN CHILDREN WITH CONGENITAL THORACIC SPINE DEFORMITY ON THE BACKGROUND OF MALSEGMENTATION OF VERTEBRAE LATERAL SURFACE

Purpose— to study alterations in the bony structures in cases of congenital deformity of the thoracic spine combined with malsegmentation of lateral surfaces of vertebrae due to pathological processes during growth period of childern and to find correlation with above alterations.Material and Methods. The study included 30 patients with congenital deformity of thoracic spine combined with malsegmentation of lateral surfaces of vertebrae. age of patients ranged from 3 to 10 years (mean of 7 years). gender distribution — 19 female and 11 male patients. all patients underwent imaging examination including spine roentgenography in two standard views in prone position as well as computer tomography.Results. Magnitude of deformity scoliotic curve was 67° (45–88°) and of pathological thoracic lordosis — 23° (18–27°). Mean number of block vertebral motion segments included into the main deformity curve was 6 (3–8). Mean distance between the outline of lateral vertebral surface and lateral outline of projection of curve root of apical vertebra on convex side of deformity (aB) was 6 mm (4–10 mm). correlation analysis demonstrated that aB distance mostly depended on the number of vertebral motion segments included into the block along non-segmental area: pearson coefficient 0.67. Based on cT scans the authors observed no rotation component of bodies’ deformity along the non-segmental area.Conclusion. Children with congenital thoracic spine deformity along with malsegmentation of lateral surfaces of vertebrae feature pathological lordosis in affected zone. alterations in the bony structures result from asymmetric growth of one half of the vertebral body at the level of non-segmentation. asymmetry severity has a strong correlation dependency from the number of vertebral bodies included in the block along the non-segmental area.

Possible systematics in the VLBI catalogs as seen from Gaia

Aims. In order to investigate the systematic errors in the very long baseline interferometry (VLBI) positions of extragalactic sources (quasars) and the global differences between Gaia and VLBI catalogs, we use the first data release of Gaia (Gaia DR1) quasar positions as the reference and study the positional offsets of the second realization of the International Celestial Reference Frame (ICRF2) and the Goddard VLBI solution 2016a (gsf2016a) catalogs. Methods. We select a sample of 1032 common sources among three catalogs and adopt two methods to represent the systematics: considering the differential orientation (offset) and declination bias; analyzing with the vector spherical harmonics (VSH) functions. Results. Between two VLBI catalogs and Gaia DR1, we find that: i) the estimated orientation is consistent with the alignment accuracy of Gaia DR1 to ICRF, of ~0.1 mas, but the southern and northern hemispheres show opposite orientations; ii) the declination bias in the southern hemisphere between Gaia DR1 and ICRF2 is estimated to be +152 μas, much larger than that between Gaia DR1 and gsf2016a which is +34 μas. Between two VLBI catalogs, we find that: i) the rotation component shows that ICRF2 and gsf2016a are generally consistent within 30 μas; ii) the glide component and quadrupole component report two declination-dependent offsets: dipolar deformation of ~+50 μas along the Z-axis, and quadrupolar deformation of ~−50 μas that would induce a pattern of sin2δ. Conclusions. The significant declination bias between Gaia DR1 and ICRF2 catalogs reported in previous studies is possibly attributed to the systematic errors of ICRF2 in the southern hemisphere. The global differences between ICRF2 and gsf2016a catalogs imply that possible, mainly declination-dependent systematics exit in the VLBI positions and need further investigations in the future Gaia data release and the next generation of ICRF.