Theoretical Study of Potential Manufacturing Insulation Defects in Medium–Voltage Traction Motors

Medium-voltage motors dedicated to the applications of traction operate in an environment with strong multi-physics constraints. Electrical insulation of these engines is a complex multi-layered impregnated system which requires a given number of steps during the manufacturing process. In the present study, we theoretically investigated the potential manufacturing insulation defects of traction motors in low frequency domain. The aim is to assess the theoretical ability of dielectric spectroscopy method for the detection of these defects and the extension of the method to others insulation systems. The theoretical study is based on numerical modelling and simulation achieved by using Comsol Multiphysics software. In our numerical modelling the properties of the main dielectric elementary materials are frequency–dependent. The identification of each potential defect is carried out by comparing its equivalent capacitance and dissipation loss spectra with the characteristics of insulation without defect. As the results, all artificial defects are identifiable with a specific relative deviation. The detection of all the defects analysed will need a measuring device with resolution of 0.4%. Keywords—AC electric motors, Capacitance, dielectric, dissipation factor, composite insulation, numerical modelling.

Improved Accuracy and Safety of Pedicle Screw Placement by Using a Probe with an Electrical Conductivity-Measuring Device during Severe Syndromic and Neuromuscular Scoliosis Spine Surgery

An electrical conductivity-measuring device (ECD) has recently been developed to support pedicle screw placement. However, no evidence exists regarding its efficacy for syndromic/neuromuscular scoliosis with extremely difficult screwing. We retrospectively reviewed 2010–2016 medical records of 21 consecutive syndromic/neuromuscular scoliosis patients undergoing free-hand segmental fixation surgery at our institution and compared the pedicle screw insertion accuracy and safety between 10 with a conventional non-ECD probe (2010–2013) and 11 with an ECD probe (2014–2016). We analyzed preoperative pedicle shape and postoperative screw placement in computed tomography. There were no significant differences between ECD and non-ECD groups in demographic, clinical, and treatment characteristics including scoliosis severity and pedicle diameter. The abandonment rate due to liquorrhea or perforation was lower in ECD (12.3%) than in non-ECD (26.7%) (p < 0.01). Acceptable insertion without perforation or <2-mm lateral/cranial position was more frequent in ECD (67.1%) than in non-ECD (56.9%) (p = 0.02). Critical ≥5-mm medial/caudal malposition was not seen in ECD (0.0%) but in non-ECD (2.4%) (p = 0.02). The perforation distance was shorter in ECD (2.2 ± 1.1 mm) than in non-ECD (2.6 ± 1.7 mm) (p = 0.01). Results involve small sample size, selection, performance, and learning curve biases; nevertheless, ECD could be useful for more accurate and safer pedicle screw placement in severe syndromic/neuromuscular scoliosis.

Color Change of Resin-based Composites After In Vitro Bleaching Protocols: A Systematic Review and Meta-analysis

SUMMARY Objectives: To systematically review the literature on color stability of resin-based composites (RBC) after in vitro bleaching protocols and to assess the influence of bleaching protocols by meta-regression analysis on RBC color stability, and the association with clinical and experimental characteristics. Methods: The electronic search was conducted in MEDLINE/PubMed, Scopus, and Web of Science databases and included English language studies that evaluated and reported color differences (CIELAB values) of RBC after in vitro bleaching procedures using hydrogen peroxide and/or carbamide peroxide. Results: Database search for color change of RBC after bleaching retrieved 1335 eligible papers after removing duplicates. After initial screening, 66 articles were assessed for full-text reading with final inclusion of 23 published papers. A meta-regression analysis showed that storage time (p≤0.01), color measuring device (p≤0.01), and background color (p≤0.01) had influenced on color changes of RBC. The bleaching protocol (bleaching agent and time of application) did not influence on color changes of RBC (p&gt;0.01). Conclusions: There is evidence that RBC change color after bleaching, but the change is not clinically significant.

Does Decoherence Select the Pointer Basis of a Quantum Meter?

The consensus regarding quantum measurements rests on two statements: (i) von Neumann’s standard quantum measurement theory leaves undetermined the basis in which observables are measured, and (ii) the environmental decoherence of the measuring device (the “meter”) unambiguously determines the measuring (“pointer”) basis. The latter statement means that the environment monitors (measures) selected observables of the meter and (indirectly) of the system. Equivalently, a measured quantum state must end up in one of the “pointer states” that persist in the presence of the environment. We find that, unless we restrict ourselves to projective measurements, decoherence does not necessarily determine the pointer basis of the meter. Namely, generalized measurements commonly allow the observer to choose from a multitude of alternative pointer bases that provide the same information on the observables, regardless of decoherence. By contrast, the measured observable does not depend on the pointer basis, whether in the presence or in the absence of decoherence. These results grant further support to our notion of Quantum Lamarckism, whereby the observer’s choices play an indispensable role in quantum mechanics.

The Importance of Selected Coordination Motor Skills for an Individual Football Player’s Effectiveness in a Game

The appropriate level of coordination motor skills (CMS) in a football player is one of the factors determining the effectiveness of their actions. Adaptability and complex reaction time are of particular importance in models of coordination requirements in football. The lead aim of this study is to determine the relationship between two selected coordination motor skills and the offensive, defensive and comprehensive effectiveness of an individual player’s actions. The study was conducted on a group of 91 Polish male football players aged 20 to 31 years, all in the senior age category. The research tools included: a test assessing motor adaptation (research by dribbling the ball with the dominant leg), psychomotor test of complex reaction time (tested with an S-10.2 measuring device) and a test of the effectiveness of an individual player’s actions (one-on-one simulation game). The conducted research indicated that adaptability and complex reaction time are both important abilities for success when attacking in an individual game, and in the assessment of a comprehensive index of individual competences in a one-on-one football game. However, the most significant factor influencing the effectiveness of a player’s defensive action is solely the complex reaction time.

Experimental Volumetric Hydrogen Uptake Determination at 77 K of Commercially Available Metal-Organic Framework Materials

Storage is still limiting the implementation of hydrogen as an energy carrier to integrate the intermittent operation of renewable energy sources. Among different solutions to the currently used compressed or liquified hydrogen systems, physical adsorption at cryogenic temperature in porous materials is an attractive alternative due to its fast and reversible operation and the resulting reduction in storage pressure. The feasibility of cryoadsorption for hydrogen storage depends mainly on the performance of the used materials for the specific application, where metal-organic frameworks or MOFs are remarkable candidates. In this work, gravimetric and volumetric hydrogen uptakes at 77 K and up to 100 bar of commercially available MOFs were measured since these materials are made from relatively cheap and accessible building blocks. These materials also show relatively high porous properties and are currently near to large-scale production. The measuring device was calibrated at different room temperatures to calculate an average correction factor and standard deviation so that the correction deviation is included in the measurement error for better comparability with different measurements. The influence of measurement conditions was also studied, concluding that the available adsorbing area of material and the occupied volume of the sample are the most critical factors for a reproducible measurement, apart from the samples’ preparation before measurement. Finally, the actual volumetric storage density of the used powders was calculated by directly measuring their volume in the analysis cell, comparing that value with the maximum volumetric uptake considering the measured density of crystals. From this selection of commercial MOFs, the materials HKUST-1, PCN-250(Fe), MOF-177, and MOF-5 show true potential to fulfill a volumetric requirement of 40 g·L−1 on a material basis for hydrogen storage systems without further packing of the powders.

Geometric system analysis of ILMD-based LID measurement systems using Monte-Carlo simulation

Imaging Luminance Measuring Device (ILMD) based luminous intensity distribution measurement systems are an established method for measuring the luminous intensity distribution (LID) of light sources in the far field. The advantage of this system is the high-resolution acquisition of a large angular range with one image. For the uncertainty budget, the mathematical description of the system can be divided into photometric and geometric contributions. In the following, we will present a Monte-Carlo approach to analyse the geometric contributions which are the uncertainty of measurement direction and measurement distance. Therefore, we set up a geometric system description based on kinematic transformations that describes the connection between detector and light source position. To consider all relevant input quantities we simulate the adjustment and measurement process. Finally, an analysis of the geometric input parameters is shown.

Research on Pressure Measuring Device with Magnetic Fluid

Magnetic fluid is a novel material which could be applied in many fields including sensors, sealings, bilmedicines, and so on. Its super magnetism and fluidity could be used in the sensor as an inducting core. Magnetic fluid and its characteristics were introduced to adapt to the application in the pressure measuring devices. A pressure measuring device with magnetic fluid was proposed and the structure was analyzed and designed according to the characteristics of magnetic fluid. The working principle of pressure measuring device with magnetic fluid was analyzed, and the structure of pressure measuring device was designed and reformed to avoid the overflow and recovery of excessive of magnetic fluid. One arm of the U tube was designed to be a large cylinder to storage large quantities of magnetic fluid. The higher the required precision is, the larger the diameter of one arm should be designed with respect to the other arm of the tube. The measuring range of designed device could also be adjusted as needed. The measuring efficiency of the device could be improved by the designing and reforming work.

Design of a high precision converter for multi-sensor information fusion

The converter is a measuring device and is used together with the displacement sensor. In view of the existing sensor transform device is susceptible to error and temperature drift effects acquisition accuracy is not high, we design a high precision transducer, multi-sensor information fusion for vehicle steering gear shaft angular displacement signal measurement, signal transformation and digital transmission. The converter has the characteristics of high precision, miniaturization and low cost. Multi-sensor information fusion high-precision converter adopts front-end signal amplifier circuit, following filter processing circuit and embedded software of microprocessor for online compensation to satisfy the requirements of high-precision transformation. The microcontroller is used as the main control chip to meet the requirements of 8-channel bipolar analog signal acquisition. Two 14-bit, 6-channel A/D chips are used to convert the bipolar analog signal in the range of ±10V, and the RS422 hardware interface circuit performs digital transmission according to the time sequence specified by the central programmer. The experimental results show that the conversion accuracy of the device can reach 0.06%, the digital signal transmission is stable, and it can be widely used in industrial production.