Implementation of the sliding-line technique in a MEC model of a linear bistable actuator

Purpose The aim of this study is to investigate the implementation of the sliding-line technique (SLT) in a generic two-dimensional (2D) nonlinear adaptive magnetic equivalent circuit (MEC) model predicting the electromagnetic force evolution of a linear bistable electromagnetic actuator technology. Design/methodology/approach The developed MEC model considers the saturation effect and the auto-adjustability of the spatial discretisation. The connection between static and mobile zones is ensured by an approach known as “air-gap sliding-line technique”, which is widely used for rotary electric motor models. To the best of the author’s knowledge, that is the first time that the SLT is implemented on an electromagnetic structure with linear motion. Findings It was found that, in case of a linear actuator with a relatively small working stroke, the implementation of the SLT could lead to some non-negligible inaccuracies. Originality/value To solve the above-mentioned problem, it was proposed to investigate the implementation of a single SLT vs double SLT. The results of the MEC models were compared with the 2D finite-element analysis (FEA) as well as with the experimental test results. The developed semi-analytical models can be easily adapted to other topologies of linear electromagnetic machines.

Optimizing Visualization in Endoscopic Spine Surgery

Given the inherent limitations of spinal endoscopic surgery, proper lighting and visualization are of tremendous importance. These limitations include a small field of view, significant potential for disorientation, and small working cannulas. While modern endoscopic surgery has evolved in spite of these shortcomings, further progress in improving and enhancing visualization must be made to improve the safety and efficacy of endoscopic surgery. However, in order to understand potential avenues for improvement, a strong basis in the physical principles behind modern endoscopic surgery is first required. Having established these principles, novel techniques for enhanced visualization can be considered. Most compelling are technologies that leverage the concepts of light transformation, tissue manipulation, and image processing. These broad categories of enhanced visualization are well established in other surgical subspecialties and include techniques such as optical chromoendoscopy, fluorescence imaging, and 3-dimensional endoscopy. These techniques have clear applications to spinal endoscopy and represent important avenues for future research.

European Science Editing is in full open access now

I am excited to announce that with this volume European Science Editing (ESE) has shifted from the print to a fully digital open access version. The journal underwent several changes last year. First of all, our publisher, the European Association of Science Editors (EASE) was generously offered – and accepted – a new ARPHA submission system (powered by PenSoft). Together with the EASE president Pippa Smart and EASE Council, we decided to transform ESE into a fully open access online journal. After several months of planning and re-thinking our strategy, a small working group (some members of the EASE Council and of ESE’s associate editors) prepared a proposal, the main idea of which was to divide the journal in two overlapping publications: European Science Editing and EASE Digest. The former will continue to publish original articles, reviews (formerly “essays”), viewpoints, and correspondence using the fully open access ARPHA submission system (flow publishing) but will drop the other sections, namely News notes, The editor’s bookshelf, This site I like, and EASE Forum Digest). These sections, which our readers consider particularly valuable, will now be published in EASE Digest with a few selected articles from ESE. The Digest will be available to EASE members only. As the proposal was accepted by the EASE Council in September 2019, the journal’s transformation is already under way. I wish to thank Silvia Maina (This site I like), Fiona Murphy (Book reviews), Elise Langdon-Neuner (EASE-Forum Digest), Anna Maria Rossi (The Editor’s bookshelf), and James Hartley and Denys Wheatley (members of the International Advisory Board) for the great work they have done and for their cooperation.

Evaluation of Autosteer in Rough Terrain at Low Ground Speed for Commercial Wild Blueberry Harvesting

Assessment of Global Navigation Satellite Signal (GNSS) autosteering is a critical step in the progression towards full wild blueberry (vaccinium angustifolium) harvester automation. The objective of the study was to analyze John Deere’s universal Auto-Trac 300 autosteer, 4640 display, and Starfire 6000 receiver with both the SF1 and SF3 signal levels for their pass-to-pass accuracy as well as how they compared versus a manual harvester operator. Incorporation of GNSS autosteer in wild blueberry harvesting has never been assessed as the slow harvester travel speeds and small working width caused the implementation to be too challenging. The results of this study concluded that there were no significant differences in pass-to-pass accuracy based on travel speeds of 0.31 m s−1, 0.45 m s−1, and 0.58 m s−1 (p = 0.174). Comparing the signal levels showed significantly greater accuracy of the SF3 system (p < 0.001), which yielded an absolute mean pass-to-pass accuracy 22.7 mm better than SF1. Neither the SF1 nor SF3 signal levels were able to reach the levels of accuracy advertised by the manufacturer. That said, both signal levels performed better than a manual operator (p < 0.001). This result serves to support the idea that in the absence of skilled operators, an autosteer system can provide significant support for new operators. Further, an autosteer system can allow any operator to focus more of their attention on operating the harvester head and properly filling storage bins. This will lead to higher quality berries with less debris and spoilage. The results of this study are encouraging and represent a significant step towards full harvester automation for the wild blueberry crop.

Scalable fault models for diagnosis in a synchronous generator using feature mapping and transformation techniques

Condition based maintenance (CBM) needs data acquired during healthy and faulty conditions to develop intelligent system for fault diagnosis. However, fault injection is not allowed/possible in a highly expensive components of complex/critical systems to collect fault condition data. Therefore, proto-type/small working models are used to conduct experiments for abnormal/fault conditions, to obtain and scale the intelligence of the system for effective health monitoring of complex system. This methodology is referred as scalable fault models. For proof of concept, in this work, we considered two different capacity synchronous generators with rating of 3 kVA and 5 kVA to emulate the behavior of prototype/small working model and complex system respectively, for scalable fault models. We explored feature mapping and transformation techniques to achieve effective scalability.From the preliminary experiments, it is observed that the baseline system performance deteriorated due to the changes in the system (capacity) and its characteristics with load changes.We therefore, expressed the input features in terms of load and system independent manner, to make the features less dependent on load and system variations. We explored localityconstrained linear coding (LLC) to express the features load/system independently. It is observed that experimenting LLC with the backend support vector machine (SVM) classifier gave the best fault classification performance for linear kernel, suggesting that the faults are linearly separable in the new feature space.Since the LLC mapped feature space is linearly separable, we then explored linear feature transformation technique, nuisance attribute projection (NAP) on the LLC mapped feature space to further minimize the load/system specific variations. We observed that LLC-NAP improved the overall accuracy and sensitivity of the classifier significantly. We also noted that the performance of NAP was limited in the original feature space since the feature space (NAP without LLC) is nonlinear with load/system variations.

DETERMINATION OF THE WORKING AREA OF THE EDGE SIEVE OF GRAIN CRUSHER WITH INCREASED SEPARATING SURFACE

Hammer crushers are widely used for the destruction of grain in feed preparation. When they work in the grinding chamber, as a result of the rotor’s rotation, air flows arise that involve particles of crushed material and whole grains in motion, thereby creating an air-productive layer. These air flows are influenced by the shape and geometrical parameters of the blades, their location, rotor diameter and speed, and the parameters of the separating surface. Under the conditions of Knyagininskiy University, a hammer crusher with an enlarged separating surface was developed, the working chamber of which was formed by two end and one peripheral sieves. Angle hammers, straight hammers, or a combination of straight hammers and corner blades placed between them were installed on the rotor as working units. The study was carried out to study the effect of the type of working units and the area of overlapping of the edge sieve on the direction of air flows in the grinding chamber and to determine the working area of the edge sieve. Angle hammers are characterized by the movement of air flows in the axial direction and their following distribution: suction into the grinding chamber in the central part of the end sieve and ejection along the outer circumference of the sieve. Based on this, the entire area of the end sieve can be divided into three parts: the suction zone, the ejection zone and the transition zone. An increase in the length of the angular blades leads to an increase in the working area of the end screens, therefore, the use of combined working units is rational. Installation of working units in the form of straight hammers is impractical, since the working area of the end screens is minimal. It is also irrational to use working units in the form of angle hammers, since they are characterized by the maximum area of the retraction zone and a small working area of the end sieves

Parallelized Additive Manufacturing of Variably Partitioned Volumes for Large Scale 3D Printing With Localized Quality

Despite the growing application of additive manufacturing (AM) in fabricating complex designs, most machines suffer from small working envelopes and slow processing speeds. One workaround to the problem of small throughput in AM is to partition the volume of a desired object and fabricate sub-volumes in parallel. Prior related work has focused on two problems. One is the geometric division problem, disregarding AM benefits and challenges in determining partitions. Others attempt to install multiple AM processing heads on the same machine, ensuring seamless bonding between deposited material from different heads while avoiding interference among them. A missed opportunity lies in deploying many independent machines simultaneously while considering benefits and limitations of AM. To that end, objects too large to be fabricated on one machine, are divided primarily into cubes that exploit benefits of AM. Specifically, the cubes are hollowed out in the direction of printing to reduce weight while avoiding the need for support structure, and depending on load conditions, packed in different orientations to mitigate material anisotropy.

Training global surgery advocates: Strengthening the global surgery voice

Objective: To strengthen medical trainees around the world on global surgery and advocacy and help develop future generations of global surgeons, anaesthesiologists, and obstetricians.Design: Training Global Surgery Advocates (TGSA), a standardized three-day advocacy workshop developed by the International Student Surgical Network (InciSioN), was built on traditional didactic lectures, role-play exercises, small working group activities, and advocacy and diplomacy training. Assessment was done using a 5-point Likert scale for 18 components regarding the perceived familiarity, knowledge, and motivation for global surgery.Setting: The training was given in the context of the pre-general assembly of the International Federation of Medical Students Associations (IFMSA) at Université Laval, in Quebec City, Canada.Participants: Twenty-five participants were selected to attend the workshop from a pool of 52 applicants, of which 14 medical students from 7 high-income countries and 7 low- and middle-income countries.Results: An average increase of 1.73 points across all 18 workshop components was observed among participants. After the workshop, all participants agreed or strongly agreed (4.64 average) on their motivation to train other medical students in their respective countries to become global surgery advocates.Conclusion: TGSA significantly improved participants’ knowledge and advocacy skills underlying global surgery. A mixed didactic and hands-on workshop appears to be feasible, enjoyable for participants, and effective in improving medical students involvement in the emerging field of global surgery.