We propose a train headlamp system using dual half-circular parabolic aluminized reflectors. Each half-circular reflector contains five high-efficiency and small-package light-emitting diode (LED) chips, and the halves are 180° rotationally symmetric. For traffic safety, the headlamp satisfies the Code of Federal Regulations. To predict the pattern of illumination, an analytical derivation is developed for the optical path of a ray that is perpendicular to and emitted from the center of an LED chip. This ray represents the main ray emitted from the LED chip and is located at the maximum illuminance of the spot projected by the LED source onto a screen. We then analyze the design systematically to determine the locations of the LED chips in the reflector that minimize electricity consumption while satisfying reliability constraints associated with traffic safety. Compared to a typical train headlamp system with an incandescent or halogen lamp needing several hundred watts, the proposed system only uses 20.18 W to achieve the luminous intensity requirements.
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http://dx.doi.org/10.1364/AO.57.001305 | DOI Listing |
Sensors (Basel)
September 2024
Faculty of Navigation, Gdynia Maritime University, 81-225 Gdynia, Poland.
Polymers (Basel)
October 2023
Department of Mechanical Engineering, College of Engineering, Shantou University, Shantou 515063, China.
This study aimed to improve the injection molding quality of LSR material lenses by optimizing the process parameters. To achieve this goal, we employed the population-based optimization algorithm NSGA-III, which can simultaneously optimize multiple objective functions and identify an equilibrium point among them, thereby reducing the time required to find the optimal process parameters. We utilized analysis software to simulate the injection molding process of LSR material lenses, with a specific focus on examining the relationship between tie bar elongation and the optimized process parameters.
View Article and Find Full Text PDFHNO
February 2022
Klinik für Hals-, Nasen- und Ohrenheilkunde, Campus Virchow Klinikum and Campus Charité Mitte, Charité - Universitätsmedizin Berlin, Corporate Member der Freien Universität Berlin and Humboldt-Universität zu Berlin, Augustenburger Platz 1, 13353, Berlin, Deutschland.
Background: The classical forehead reflector as traditionally used by ear, nose, and throat (ENT) physicians for the ENT examination is now iconic for doctors in general. It is unknown which instruments are currently used in Germany to clinically examine ENT patients. Therefore, this study aims to present results of a survey about commonly used instruments.
View Article and Find Full Text PDFGMS J Med Educ
October 2021
Universitätsklinikum Würzburg, Klinik und Poliklinik für Hals-, Nasen- und Ohrenkrankheiten, plastische und ästhetische Operationen, Würzburg, Germany.
The development of presentation-free teaching formats for practical exercises is a particular challenge. The objective of the presented project was the implementation of the practical course in otorhinolaryngology for learning examination techniques through digital distance learning. Disposable instruments for a comprehensive otorhinolaryngologic examination were purchased and made available to the students.
View Article and Find Full Text PDFSensors (Basel)
July 2020
School of Computer Science and Technology, China University of Mining and Technology, Xuzhou 221116, China.
The mine cage has an important role in the production of coal mines. It has many safety problems in the transportation of people, such as overloading of personnel and illegal outreach of human limbs. However, the harsh mine environment makes it very difficult to monitor personnel overload and limb extension.
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