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Aggarwal, Sahil, C. Ellis Wisely, Andrew Gross i Pratap Challa. "Transition to a Night Float System in Ophthalmology Residency: Perceptions of Resident Wellness and Performance". Journal of Academic Ophthalmology 14, nr 01 (styczeń 2022): e120-e126. http://dx.doi.org/10.1055/s-0042-1747969.
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Abstract Purpose The purpose of this study is to characterize the influence of a new night float rotation on resident wellness and performance in the Duke University Eye Center Ophthalmology Residency Program. Methods We analyzed three classes of ophthalmology residents: one class (n = 4) utilized the new night float rotation with no daytime clinical duties, while two senior classes (n = 12) utilized the traditional call system wherein they had daytime and nighttime responsibilities. Residents completed a questionnaire regarding their perceptions of the night float rotation. Supervising attendings (n = 15) were also surveyed about their perceptions of the new rotation. Results Zero of the four residents on the night float rotation reported burnout compared with 6 of 11 residents in the traditional call system. Most residents supported the adoption of the night float rotation, but this trend was less apparent among fellows and attendings.Most respondents believed the new night float rotation reduced burnout, fatigue, and work hours while increasing time for nonclinical activities. Perceived skills gained while on call were felt to be similar between the two call systems. Fellows and attendings believed residents in the night float system performed similarly or better than residents in the traditional system in indicators such as knowledge and enthusiasm. There was no significant difference in the average number of patient encounters (290.8 ± 30.5 vs. 310.7 ± 25.4, p = 0.163), phone encounters (430.8 ± 20.2 vs. 357.1 ± 90.0, p = 0.068), or average hours worked per week (57.3 ± 4.6 vs. 58.0 ± 5.7 p = 0.797) per resident between night float residents and traditional call residents. Conclusions This study shows resident support for a night float rotation in ophthalmology residency at Duke, with reductions in burnout and more time for nonclinical activities without affecting perceived clinical performance. We hope this study serves as an impetus for other ophthalmology programs considering a transition to a night float system.
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Sadowski, Brett W., Hector A. Medina, Joshua D. Hartzell i William T. Shimeall. "Nighthawk: Making Night Float Education and Patient Safety Soar". Journal of Graduate Medical Education 9, nr 6 (1.12.2017): 755–58. http://dx.doi.org/10.4300/jgme-d-17-00259.1.
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ABSTRACT Background Some residency programs responded to duty hour restrictions by implementing night rotations. Night supervision models can vary, resulting in potential patient safety issues and educational voids for residents. Objective We evaluated the impact of multiple evidence-based interventions on resident satisfaction with supervision, perception of the education value of night rotations, and residents' use of online educational materials. Methods The night team was augmented with an intern to assist with admissions and a senior resident (the “nighthawk”) to supervise inpatient care and deliver a night medicine curriculum. We instituted a “must-call” list, with specific clinical events requiring mandatory attending notification, and reduced conflict in the role of the night float team. We studied patient contact, online curriculum use, residents' perceptions of nighthawk involvement, exposure to educational materials, and satisfaction with supervision. Results During the first half of academic year 2016–2017, 51% (64 of 126) of trainees were on the night medicine rotation. The nighthawk reviewed 1007 intern plans (15 per night; range, 6–36) and supervised 215 hands-on evaluations, including codes and rapid responses (3 per night; range, 0–12). The number of users of the online education materials increased by 85% (13 to 24), and instances of use increased 35% (85 to 115). The majority of residents (79%, 27 of 34) favored the new system. Conclusions A nighthawk rotation, a must-call list, and reducing conflict in night team members' roles improved resident satisfaction with supervision and the night medicine rotation, resulting in increased communication.
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Jung, Jung-Mo, Yoshiki Matsushita i Seonghun Kim. "Study on Reducing Towing Drag by Varying the Shape and Arrangement of Floats and Gears". Applied Sciences 12, nr 15 (28.07.2022): 7606. http://dx.doi.org/10.3390/app12157606.
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Many studies have been conducted with the aim of reducing fuel consumption by the fishing industry. We examined whether drag can be reduced by changing the arrangement of gears without requiring the development of new parts for the conventional float and ground gear. Ten differently shaped floats and ground gears were measured in a water flume tank. The float and ground gear were fixed to a steel rod to measure fluid drag according to attack angle, using a multi-component load cell. To estimate the frictional drag of ground gear on the seabed, five types of large ground gear were towed on flat land while changing attack angle using the load cell to measure tension. The fluid drag of the float and ground gear was highest at an attack angle of 60°, regardless of shape, size, and flow velocity. The resistance coefficients of the float and ground gear varied depending on the attack angle and tended to be lower at small attack angles. The frictional drag of the ground gear was greater when the axis of rotation had a small attack angle in the towing direction compared to other attack angles. We then investigated a method for designing bottom-towed gear that reduces drag while maintaining the size, buoyancy, and sinking force of conventional fishing gear parts. This gear design showed 1.2% drag reduction and an estimated 0.8% improvement in fuel efficiency per haul.
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Scali, Elena P., Evgeny Strovski, Bruce B. Forster, Colin Mar i Silvia D. Chang. "Sink or Night Float: University of British Columbia Radiology Residents' Experience with Overnight Call". Canadian Association of Radiologists Journal 66, nr 2 (maj 2015): 185–89. http://dx.doi.org/10.1016/j.carj.2014.07.003.
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Purpose In July 2012, in response to residents' concerns regarding the impact of the traditional 24-hour call system on their personal well-being and educational experience, the University of British Columbia Radiology residency program adopted a 12-hour night float system. This shift takes place in the context of increasing concerns, both across Canada and internationally, about resident well-being and the impact of prolonged duty hours on patient care. Methods An anonymous survey was distributed to all 25 postgraduate years 2-5 University of British Columbia radiology residents 12 months after the introduction of night float. This study sought to solicit residents' feedback about these changes and to identify potential future changes to optimize the call system. Results The response rate was 100%; 96% of residents were in favor of continuing with night float rather than the traditional call system; 72% of residents reported that their judgement was affected secondary to being on night float. Although most residents described varying degrees of impairment, the rate of acute discrepancies between resident preliminary and attending radiologist final reports decreased by more than half, from 2% to less than 1%. Conclusions The vast majority of our residents were in favor of maintaining the night float call system. Night float had a beneficial effect on the resident educational experience: by eliminating the pre-call morning and post-call day off rotation, residents gained an additional 24 days per year on other clinical rotations.
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Kozlov, Victor G., i Stanislav V. Subbotin. "Vibrational Suspension of Light Sphere in a Tilted Rotating Cylinder with Liquid". Advances in Acoustics and Vibration 2014 (16.03.2014): 1–6. http://dx.doi.org/10.1155/2014/608058.
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The dynamics of a light sphere in a quickly rotating inclined cylinder filled with liquid under transversal vibrations is experimentally investigated. Due to inertial oscillations of the sphere relative to the cavity, its rotation velocity differs from the cavity one. The intensification of the lagging motion of a sphere and the excitation of the outstripping differential rotation are possible under vibrations. It occurs in the resonant areas where the frequency of vibrations coincides with the fundamental frequency of the system. The position of the sphere in the center of the cylinder could be unstable. Different velocities of the sphere are matched with its various quasistationary positions on the axis of rotating cavity. In tilted rotating cylinder, the axial component of the gravity force appears; however, the light sphere does not float to the upper end wall but gets the stable position at a definite distance from it. It makes possible to provide a vibrational suspension of the light sphere in filled with liquid cavity rotating around the vertical axis. It is found that in the wide range of the cavity inclination angles the sphere position is determined by the dimensionless velocity of body differential rotation.
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Weidman, Patrick D., i Michael A. Sprague. "Steady and unsteady modelling of the float height of a rotating air hockey disk". Journal of Fluid Mechanics 778 (30.07.2015): 39–59. http://dx.doi.org/10.1017/jfm.2015.374.
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A similarity reduction of the Navier–Stokes equations for the motion of an infinite rotating disk above an air-bearing table yields a coupled pair of ordinary differential equations governed by a Reynolds number $Re=Wh/{\it\nu}$ and a rotation parameter $S=\sqrt{2}h{\it\Omega}/W$, where $h$ is the float height, $W$ is the air levitation velocity, ${\it\Omega}$ is the disk rotation rate, and ${\it\nu}$ is the kinematic viscosity of air. After deriving the small- and large-Reynolds-number behaviour of solutions, the equations are numerically integrated over a wide range of $Re{-}S$ parameter space. Zero-lift boundaries are computed as well as the boundaries separating pure outward flow from counter-flow in the gap. The theory is used to model the steady float height of a finite-radius air hockey disk under the assumption that the float height is small relative to the diameter of the disk and the flow is everywhere laminar. The steady results are tested against direct numerical simulation (DNS) of the unsteady axisymmetric Navier–Stokes equations for the cases where the disk rotates at constant angular velocity but is either at a fixed height or free to move axially. While a constant shift in the gap pressure conforms closely to that found using steady theory, the interaction of the radial jet emanating from the gap with a vertical transpiration field produces vortex rings which themselves propagate around to interact with the jet. Although these structures diffuse as they propagate up and away from the gap, they induce a departure from the steady-flow assumption of atmospheric pressure at the gap exit, thus inducing small irregular axial oscillations of the floating disk.
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DeFilippis, Andrew Paul, Ildefonso Tellez, Neil Winawer, Lorenzo Di Francesco, Kimberly D. Manning i Sunil Kripalani. "On-site Night Float by Attending Physicians: A Model to Improve Resident Education and Patient Care". Journal of Graduate Medical Education 2, nr 1 (1.03.2010): 57–61. http://dx.doi.org/10.4300/jgme-d-09-00073.1.
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Abstract Background In 2003, the Accreditation Council for Graduate Medical Education instituted common duty hour limits, and in 2008 the Institute of Medicine recommended additional limits on continuous duty hours. Using a night-float system is an accepted approach for adhering to duty hour mandates. Objective To determine the effect of an on-site night-float attending physician on resident education and patient care. Methods Night-float residents and daytime ward residents were surveyed at the end of their rotation about the impact of an on-site night-float attending physician on education and quality of patient care. Responses were provided on a 5-point Likert scale ranging from 1, strongly agree, to 5, strongly disagree. Results Overall, 92 of the 140 distributed surveys were completed (66% response rate). Night-float residents found the night-float attending physician to be helpful with cross-cover issues (mean = 2.00), initial history and physical examination (mean = 1.56), choosing appropriate diagnostic tests (mean = 1.79), developing a treatment plan (mean = 1.74), and improving overall patient care (mean = 1.91). Daytime ward residents were very satisfied with the quality of the admission workups (mean = 1.78), tests and diagnostic procedures (mean = 1.76), and initial treatment plan (mean = 1.62) provided by the night-float service. Conclusion A night-float system that includes on-site attending physician supervision can provide a valuable opportunity for resident education and may help improve the quality of patient care.
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Nikiforov, A. N., G. Ya Panovko i V. P. Roizman. "Conditions for stable rotation of a rotor with a float self-balancer". Mechanics of Solids 50, nr 3 (maj 2015): 353–58. http://dx.doi.org/10.3103/s0025654415030115.
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Lafleur, Alexandre, Adrien Harvey i Caroline Simard. "Adjusting to duty hour reforms: residents’ perception of the safety climate in interdisciplinary night-float rotations". Canadian Medical Education Journal 9, nr 4 (13.11.2018): e111-119. http://dx.doi.org/10.36834/cmej.43345.
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Background: New scheduling models were needed to adjust to residents’ duty hour reforms while maintaining safe patient care. In interdisciplinary night-float rotations, four to six residents from most residency programs collaborated for after-hours cross-coverage of most adult hospitalised patients as part of a Faculty-led rotation. Residents worked sixteen 12-hour night shifts over a month. Methods: We measured residents’ perception of the patient safety climate during implementation of night-float rotations in five tertiary hospitals. We surveyed 267 residents who had completed the rotation in 2015-2016 with an online version of the Safety Attitudes Questionnaire. First year residents came from most residency programs, second- and third-year residents came from internal medicine.Results: One-hundred-and-thirty residents completed the questionnaire. Scores did not differ across hospitals and residents’ years of training for all six safety-related climate factors: teamwork climate, job satisfaction, perceptions of management, safety climate, working conditions, and stress recognition.Conclusion: Simultaneous implementation in five hospitals of a Faculty-led interdisciplinary night-float rotation for most junior residents proved to be logistically feasible and showed similar and reassuring patient safety climate scores._____Contexte: De nouveaux horaires de garde en établissements hospitaliers étaient nécessaires pour s’adapter aux réformes des heures de travail des résidents tout en maintenant des soins sécuritaires pour les patients. Dans les stages cliniques de nuit interdisciplinaires, quatre à six résidents de la plupart des programmes de résidence ont collaboré pour assurer une couverture croisée, après les heures normales de travail, de la plupart des patients adultes hospitalisés. Les résidents ont travaillé seize nuits de 12 heures durant un mois.Méthodes: Nous avons mesuré la perception des résidents du climat de travail lié à la sécurité des patients lors de la mise en place de stages de nuit dans cinq hôpitaux universitaires. Nous avons interrogé 267 résidents ayant terminé le stage en 2015-2016 avec une version numérique du Safety Attitudes Questionnaire. Les résidents de première année provenaient de la plupart des programmes de résidence, les résidents de deuxième et troisième années provenaient du programme de médecine interne.Résultats: 130 résidents ont complété le questionnaire. Les scores ne différaient pas entre les hôpitaux et les années de formation des résidents pour les six facteurs liés à la sécurité des patients: climat de travail en équipe, satisfaction au travail, perceptions des supérieurs, climat de sécurité, conditions de travail et reconnaissance du stress.Conclusions: La mise en place simultanée, dans cinq hôpitaux, de stages cliniques de nuit réunissant des résidents juniors de la majorité des programmes de résidence fut logistiquement possible et a montré des résultats similaires et rassurants sur le climat de travail lié à la sécurité des patients.
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Fang, Hong Wei, Jia Jia Cheng, Qi Wei Yang i Jing Lian. "Multi-Frequency Proportional-Resonant Control for Wave Power Generation System". Advanced Materials Research 760-762 (wrzesień 2013): 1139–43. http://dx.doi.org/10.4028/www.scientific.net/amr.760-762.1139.
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A grid voltage vector oriented proportional resonant (PR) control strategy is applied to the grid current control of the float-type wave power generation system. Compared with the conventional double closed-loop proportional integral (PI) control method, the proposed multi-frequency PR control method can realize zero steady-state error in AC input signal in the stationary frame, without complex coordinate rotation transformation and decoupling control. The overall wave power generation system model is built with Matlab/Simulink to evaluate the performance of the PR control method. Simulation results have shown that the PR control can well improve the robustness and the power quality of the float-type wave energy conversion control system.
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Kelly, R. J., i C. Senkowski. "Effect of night float rotation on operative case volume for surgical chief residents". Journal of Surgical Education 66, nr 2 (marzec 2009): 68. http://dx.doi.org/10.1016/j.jsurg.2009.03.016.
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Shi, Jiayi, Gang Chen i Xuelei Shen. "Visual measurement system for three dimensional rotation attitudes of the air float turntable". Optik 222 (listopad 2020): 165229. http://dx.doi.org/10.1016/j.ijleo.2020.165229.
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Cavallo, Anita, Julie Jaskiewicz i M. Douglas Ris. "IMPACT OF NIGHT-FLOAT ROTATION ON SLEEP, MOOD, AND ALERTNESS: THE RESIDENT'S PERCEPTION". Chronobiology International 19, nr 5 (styczeń 2002): 893–902. http://dx.doi.org/10.1081/cbi-120014106.
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Ma, Nancy, John S. Walker, Anke Lüdge i Helge Riemann. "Silicon Float Zone Process with a Weak Transverse Magnetic Field and Crystal Rotation". Journal of The Electrochemical Society 147, nr 9 (2000): 3529. http://dx.doi.org/10.1149/1.1393932.
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Greene, James G. "Neurohospitalists Enhance Resident Perception of the Educational and Clinical Value of a Night Float Rotation". Neurohospitalist 3, nr 4 (15.07.2013): 179–84. http://dx.doi.org/10.1177/1941874413495879.
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Nguyen, C. T., H. Bazzi i J. Orfi. "NUMERICAL INVESTIGATION OF THE EFFECTS OF ROTATION ON A GERMANIUM FLOAT ZONE UNDER MICROGRAVITY CONDITIONS". Numerical Heat Transfer, Part A: Applications 28, nr 6 (grudzień 1995): 667–85. http://dx.doi.org/10.1080/10407789508913768.
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Ragel, Brian T., Mark Piedra, Paul Klimo, Kim J. Burchiel, Heidi Waldo, Shirley McCartney i Nathan R. Selden. "An ACGME Duty Hour Compliant 3-Person Night Float System for Neurological Surgery Residency Programs". Journal of Graduate Medical Education 6, nr 2 (1.06.2014): 315–19. http://dx.doi.org/10.4300/jgme-d-13-00172.1.
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Abstract Background In 2003, the Accreditation Council for Graduate Medical Education (ACGME) instituted the 24+6-hour work schedule and 80-hour workweek, and in 2011, it enhanced work hour and supervision standards. Innovation In response, Oregon Health & Science University's (OHSU) neurological surgery residency instituted a 3-person night float system. Methods We analyzed work hour records and operative experience for 1 year before and after night float implementation in a model that shortened a combined introductory research and basic clinical neurosciences rotation from 12 to 6 months. We analyzed residents' perception of the system using a confidential survey. The ACGME 2011 work hour standards were applied to both time periods. Results After night float implementation, the number of duty hour violations was reduced: 28-hour shift (11 versus 235), 8 hours off between shifts (2 versus 20), 80 hours per week (0 versus 17), and total violations (23 versus 275). Violations increased only for the less than 4 days off per 4-week interval rule (10 versus 3). No meaningful difference was seen in the number of operative cases performed per year at any postgraduate year (PGY) training level: PGY-2 (336 versus 351), PGY-3 (394 versus 354), PGY-4 (803 versus 802), PGY-5 (1075 versus 1040), PGY-7 (947 versus 913), and total (3555 versus 3460). Residents rated the new system favorably. Conclusions To meet 2011 ACGME duty hour standards, the OHSU neurological surgery residency instituted a 3-person night float system. A nearly complete elimination of work hour violations did not affect overall resident operative experience.
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Pavlovskii, M. A., Yu V. Radysh i A. S. Kireev. "Rotation of a solid with a complicated shape in a float suspension containing a liquid jet". Soviet Applied Mechanics 27, nr 4 (kwiecień 1991): 406–11. http://dx.doi.org/10.1007/bf00896522.
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Hsu, Je-Yuan, Ren-Chieh Lien, Eric A. D’Asaro i Thomas B. Sanford. "Estimates of Surface Waves Using Subsurface EM-APEX Floats under Typhoon Fanapi 2010". Journal of Atmospheric and Oceanic Technology 35, nr 5 (maj 2018): 1053–75. http://dx.doi.org/10.1175/jtech-d-17-0121.1.
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AbstractSeven subsurface Electromagnetic Autonomous Profiling Explorer (EM-APEX) floats measured the voltage induced by the motional induction of seawater under Typhoon Fanapi in 2010. Measurements were processed to estimate high-frequency oceanic velocity variance associated with surface waves. Surface wave peak frequency fp and significant wave height Hs are estimated by a nonlinear least squares fitting to , assuming a broadband JONSWAP surface wave spectrum. The Hs is further corrected for the effects of float rotation, Earth’s geomagnetic field inclination, and surface wave propagation direction. The fp is 0.08–0.10 Hz, with the maximum fp of 0.10 Hz in the rear-left quadrant of Fanapi, which is ~0.02 Hz higher than in the rear-right quadrant. The Hs is 6–12 m, with the maximum in the rear sector of Fanapi. Comparing the estimated fp and Hs with those assuming a single dominant surface wave yields differences of more than 0.02 Hz and 4 m, respectively. The surface waves under Fanapi simulated in the WAVEWATCH III (ww3) model are used to assess and compare to float estimates. Differences in the surface wave spectra of JONSWAP and ww3 yield uncertainties of <5% outside Fanapi’s eyewall and >10% within the eyewall. The estimated fp is 10% less than the simulated before the passage of Fanapi’s eye and 20% less after eye passage. Most differences between Hs and simulated are <2 m except those in the rear-left quadrant of Fanapi, which are ~5 m. Surface wave estimates are important for guiding future model studies of tropical cyclone wave–ocean interactions.
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Sheleg, V. K., M. A. Levantsevich, Y. V. Pilipchuk, M. A. Kravchuk, I. A. Bogdanovich i T. Ya Bogdanova. "Alloying the Melt of Sliding Bearings Based on Babbitt". Science & Technique 19, nr 6 (27.11.2020): 475–79. http://dx.doi.org/10.21122/2227-1031-2020-19-6-475-479.
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Abstract. A device design is proposed that makes it possible to obtain composite castings of sliding bearings based on babbitt by mixing alloying additives from antifriction powders of solid lubricants (graphite, molybdenum disulfide, etc.) into the melt, having a density significantly lower than the density of babbitt itself. The principle of mixing is based on the use of numerous turbulent flows resulting from the rotation of a gating rod with a wire pile in the melt material, the packing density coefficient of which is not less than 0.1. Due to the suction effect of these flows, non-metallic particles of solid lubricant powder do not float to the surface of the melt and, after crystallization, remain in the body of the casting. The supply of alloying powder of solid lubricant is carried out simultaneously with the supply of the babbitt melt through the central and distribution gating channels made in a rotating rod. Under the action of centrifugal forces, powder particles and melt material flow through distribution channels to the walls of the mold (mold), passing through the rotation zone of the metal pile. In this case, intensive mixing of the powder particles with the melt material occurs due to the suction effect of turbulent flows arising behind the moving pile. In addition, as a result of the rotation of the wire pile, dendritic constituents are crushed in babbitt castings. Metallographic studies of the castings obtained on the developed device have shown that the structure of the casting obtained by traditional technology contains large quantities of solid crystals of intermetallic compounds SnSb and Cu3Sn, while in the structure of the casting obtained using the proposed device, along with the aforementioned intermetallic compounds, particles of solid lubricant C + MoS2 powder embedded in the crystallized melt are observed.
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Liu, Miao, Peng Zhai, Qiang Long, Chun Yang Wang i Bo Han Xiao. "Kinetics of Cavitation Bubble in Ultrasonic Degassing of Casting Aluminium Alloy". Materials Science Forum 896 (marzec 2017): 175–81. http://dx.doi.org/10.4028/www.scientific.net/msf.896.175.
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Severe regassing was detected by previous experiment on degassing method for aluminium-silicon alloy by injecting argon with rotation. In order to further degas, ultrasonic degassing was adopted. To describe the cavitation bubbles’ movement, traditional Rayleigh-Plesset equation was modified. Classic Rayleigh-Plesset equation is strongly restricted by the applicable condition that the centre of the bubble is fixed. In this paper, a position-related Rayleigh-Plesset equation is proposed to describe the cavitation bubble's floating movement in aluminium-silicon alloy of 750°C with the coefficient of viscosity of 0.0012. As the calculation results, a bubble stimulated by high-low-frequency vibration can float up faster with violent vibration.
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Almoosa, Khalid F., Linda M. Goldenhar, Jonathan Puchalski, Jun Ying i Ralph J. Panos. "Critical Care Education During Internal Medicine Residency: A National Survey". Journal of Graduate Medical Education 2, nr 4 (1.12.2010): 555–61. http://dx.doi.org/10.4300/jgme-d-10-00023.1.
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Abstract Background Current training practices and teaching methods for critical care medicine education during internal medicine residency have not been well described. This study explored critical care medicine education practices and environments for internal medicine residents in the United States. Methods A web-based survey recruited Pulmonary and Critical Care Medicine fellowship program directors involved with internal medicine residency programs at academic institutions in the United States. Results Of 127 accredited Pulmonary and Critical Care Medicine programs in 2007, 63 (50%) responded. Demographics of the intensive care units varied widely in size (7–52 beds), monthly admissions (25–300 patients), and presence of a “night float” (22%) or an admissions “cap” (34%). All programs used bedside teaching, and the majority used informal sessions (91%) or didactic lectures (75%). More time was spent on resident teaching in larger (≥20 bed) medical intensive care units, on weekdays, in programs with a night-float system, and in programs that suspended residents' primary care clinic duties during their intensive care unit rotation. Conclusions Although similar teaching methods were used within a wide range of training environments, there is no standardized approach to critical care medicine education for internal medicine residents. Some survey responses indicated a correlation with additional teaching time.
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Prayitnoadi, R. P., B. S. Wibowo, A. Pamungkas, A. Islamiyah, M. Lestari, R. Putri, R. F. Ridwan i F. Rosa. "Analysis of linkage type sea wave power plant design through motion study and 3D printed modelling". IOP Conference Series: Earth and Environmental Science 926, nr 1 (1.11.2021): 012011. http://dx.doi.org/10.1088/1755-1315/926/1/012011.
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Abstract Sustainable energy generation is becoming increasingly important because of the expected limitations in current energy resources and for reducing pollution. Wave energy generation has seen significant developments in recent years. This research has produced a linkage-type PLTGL design that utilizes ocean waves to raise and lower the float lever and move the linkage mechanism which then causes a back and forth movement of the rack gear which will rotate the pinion and cause the dynamo drive shaft to rotate. Using ocean wave data in the waters of Tanjung Berikat, Bangka Tengah, and with the help of the SolidWorks application, this design is then simulated to determine the resulting movement and rotation. The rotation generated through the simulation can reach 532 Rpm with the assumption that it does not involve friction forces and material loads that exist in the PLTGL design. This design was made in 3D using the CR-10 V3 type 3D printing machine which produced a model with a scale of 25% of the original design. The model is used as a discussion material for designers to improve the design.
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Morozov, Iurii, i Pavel Penkov. "Studying the possibilities of improving centrifugal separation efficiency". Izvestiya vysshikh uchebnykh zavedenii Gornyi zhurnal, nr 3 (14.05.2020): 80–86. http://dx.doi.org/10.21440/0536-1028-2020-3-80-86.
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Object and aim of research. One direction in improving valuable components extraction in centrifugal separation is to apply it in the scheme of circular concentration. By means of multiple passing of a pulp flow through the centrifugal separator, higher indicators of valuable component extraction in heavy residue are ensured. The aim of this research is to study the possibility of improving the efficiency of centrifugal separation based on float circulation. Methodology. Laboratory testing has been carried out to cope with the given task. Centrifugal separation has been fulfilled in a laboratory fortex formation centrifugal separator K-200VL under the cone rotation 86 "Izvestiya vysshikh uchebnykh zavedenii. Gornyi zhurnal". No. 3. 2020 ISSN 0536-1028 frequency of 1000 r/min. Hydrocycloning has been carried out in cyclone separator GTs-75 with the apex diameter of 1.7 cm. The obtained concentrate and tailings were subject to gold assay test. According to the results of the assay test, the calculation of gold extraction in heavy residue and float has been fulfilled. Summary. The obtained result testifies to high efficiency of the proposed technical solution. The proposed technical solution ensures improved efficiency of the process by means of increasing the extraction of particles of increased density in the concentrate when increasing its quality and reducing specific water consumption for the process
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Zheng, Wei Hong, Yang Dai, Mo Zhou Lin, Kun Yang i Hao Wu. "The Effect of Fluorine on the Viscosity and Crystallization of Lithium Aluminosilicate Glasses". Key Engineering Materials 509 (kwiecień 2012): 346–52. http://dx.doi.org/10.4028/www.scientific.net/kem.509.346.
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Lithium aluminosilicate glasses have high viscosities, resulting in high melting temperatures and processing temperatures. In this study, F was added to the LAS glasses to reduce the melting temperature and viscosity for float process. The effects of fluorine content on the viscosity and crystallization of the parent glasses were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), differential thermal analysis (DTA) and rotation viscometer. It was found that the addition of F was useful in reducing the melting temperature and viscosity. The main crystalline phase of resulting glass-ceramics was β-spodumene. The activation energy (E) of LAS glasses was decreased from 460.3 KJ/mol to 417.7 KJ/mol with the addition of 2.63 wt% F, which accelerated the crystallization and enhanced the crystallinity of specimens.
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Woothipatanapan, Sakhon, i Poonsri Wannakarn. "Design and Construction of a Mini Magnetic Levitation Train". Applied Mechanics and Materials 891 (maj 2019): 253–62. http://dx.doi.org/10.4028/www.scientific.net/amm.891.253.
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This article presents the design and construction of a mini magnetic levitation train. The design of the train is based on the theory of 3-phase Linear Induction Motor (LIM). The train consists of two main sections. The first part is the linear induction motor, which is the part that drives the train to move. The second part is the magnetic field winding, which is the part that raises the body of the train to float over the rails. Such train can move forward/backward in the same principle as forward/reverse rotation control of 3-phase induction motors. For that reason, this research controls the forward/backward movement of the train with a magnetic contactor set by using the same circuit as the control of the rotation of the 3-phase induction motor. The designed train can lift 1 mm above the rails and move within a distance of 1.48 m along the length of the rails. The test results showed drive voltage, drive force, average time and drive speed of the train. From the details and results of this article can be used as a guide to create a larger magnetic levitation train, which can be used more effectively.
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Jiang, Xionghua. "Using a Novel Floating Grinding Process to Improve the Surface Roughness Parameter of a Magnetic Head". Nanomaterials 12, nr 16 (12.08.2022): 2763. http://dx.doi.org/10.3390/nano12162763.
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This work concentrated on the improvement of the surface roughness of a magnetic head, through the use of an ultrafine nanodiamond slurry, and a novel floating grinding process, which optimize different experimental factors required for the fine grinding of a magnetic head. The preparation of the grinding plate was confirmed by the observation of the surface change, depth detection, and flatness after ultrafine nanodiamonds were embedded into it by a Keyence high-power microscope at a 20 K magnification. The flatness was measured by a TOTO instrument. The optimum conditions were found to be a pit ratio reach of 30:70 and a plate flatness (average) of 1.8 μm. The rotation speed and vibration frequency were 0.3 and 10 rpm, respectively, for the grinding process. The morphology, size, and elemental composition of blackspots were investigated by SEM, AES, AFM, and transmission electron microscopy (TEM) analysis, which showed that the diameter of the diamonds in the slurry was important for grinding surface improvement. A novel method was proposed in this study to fine grind a magnetic head using a small-sized diamond slurry (100 nm) in conjunction with a novel float lapping method. Comparison experiments were performed under both normal conditions and improved conditions. The results show that by using the novel float lapping method with a small-sized diamond slurry, the minimum roughness was obtained. The finest roughness obtained for the slider surface reached 0.165 nm without blackspots or scratches.
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Shcherbina, A. Y., M. C. Gregg, M. H. Alford i R. R. Harcourt. "Three-Dimensional Structure and Temporal Evolution of Submesoscale Thermohaline Intrusions in the North Pacific Subtropical Frontal Zone". Journal of Physical Oceanography 40, nr 8 (1.08.2010): 1669–89. http://dx.doi.org/10.1175/2010jpo4373.1.
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Abstract Four instances of persistent intrusive deformation of the North Pacific Subtropical Front were tagged individually by a Lagrangian float and tracked for several days. Each feature was mapped in three dimensions using repeat towed observations referenced to the float. Isohaline surface deformations in the frontal zone included sheetlike folds elongated in the alongfront direction and narrow tongues extending across the front. All deformations appeared as protrusions of relatively cold, and fresh, water across the front. No corresponding features of the opposite sign or isolated lenslike structures were observed. The sheets were O(10 m) thick, protruded about 10 km into the warm saline side of the front, and were coherent for 10–30 km along the front. Having about the same thickness and cross-frontal extent as the sheets, tongues extended less than 5 km along the front. All of the intrusions persisted as long as they were followed, several days to one week. Their structures evolved on both inertial (23 h) and subinertial (∼10 days) time scales in response to differential lateral advection. The water mass surrounding the intrusions participated in gradual anticyclonic rotation as a part of a mesoscale meander of the subtropical front. The intrusions may be interpreted as a manifestation of three-dimensional submesoscale turbulence of the frontal zone, driven by the mesoscale. Absence of large features of the opposite sign may be indicative of the asymmetry of the underlying dynamics.
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Knowles, Kevin M., Bin Li, Callum N. F. Ramsey i Robert P. Thompson. "Microstructural Characterisation of Devitrite, Na2Ca3Si6O16". Advanced Materials Research 585 (listopad 2012): 51–55. http://dx.doi.org/10.4028/www.scientific.net/amr.585.51.
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On suitably heat treated samples of float glass, devitrite, Na2Ca3Si6O16, nucleates heterogeneously on the glass surface and grows as thin needles with a distinct [100] growth axis. The needles group together as spherulites and show evidence of low-angle branching in order to fill space. Analysis of the rate of needle growth along [100] between 680°C and 950°C suggests that the activation energy for diffusion governing the transport across the devitrite–glass interface is 260 kJ mol–1, somewhat higher than previous analyses have suggested. The devitrite needles are often twinned, with the twins related to one another by a Type II twinning rotation of 180° about the [100] growth axis direction. The formally irrational twin plane is very close to (010). Molecular dynamics simulations have been undertaken to establish the form of these twin interfaces to understand how and why devitrite twins in this manner.
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Devine, J. K., L. P. Schwartz, S. R. Hursh, E. Mosher, S. Schumacher, L. Boyle, J. E. Davis, M. Smith i S. Fitzgibbons. "0184 Predicting Strategic Napping in Surgical Residents by Individual and Rotation Characteristics". Sleep 43, Supplement_1 (kwiecień 2020): A72—A73. http://dx.doi.org/10.1093/sleep/zsaa056.182.
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Abstract Introduction Strategic napping, or napping on-shift, is recommended to reduce fatigue in medical residents. The actual prevalence of strategic napping in relation to residents’ workload, schedule, or demographics is largely unquantified. This study objectively measured sleep patterns and work schedules in surgical residents working a variety of service lines over a two-month period in order to identify which resident and service line attributes predict on-shift napping. Methods Surgical residents from an academic surgery program in the Washington, DC area provided schedule information, completed the Epworth Sleepiness Scale (ESS), and wore sleep-tracking devices (Zulu Watch) continuously for 8 weeks. Multiple linear regression was performed to predict percent days with on-shift napping from resident demographics (age, gender, post graduate year (PGY), sleep characteristics (ESS, total sleep time (TST), sleep efficiency (SE)), schedule characteristics (shift start time, shift length, rotation length, percent days on-shift, percent night shifts), and service line characteristics (service line category, number of service lines worked). Results Twenty-two (n=22) residents completed the study, rotating through at least 1 of 5 different service line categories (Acute Non-Elective Surgery, Elective Surgery, Night Float, Surgical Intensive Care Unit, and Other). Residents slept an average of 6 hours within a 24-hour period (370±129 minutes) with normal SE (87.13%±7.55%). ESS scores indicated excessive daytime sleepiness (11.64±4.03). Ninety-five percent (n=21) of residents napped at least once while on shift. Residents napped on-shift approximately 32% of their working days and were most likely to nap when working between 2300-0500 hours. Earlier shift start times predicted less on-shift napping (B=-0.08,SE=0.04,β=-2.40,t=-2.09,p=0.05) while working more night shifts (B=1.55,SE=0.44,β=4.12,t=3.52,p=0.003) and shifts over 24 hours. Conclusion Residents take advantage of opportunities to nap on-shift, particularly when working at night. Despite naps, however, residents exhibit insufficient sleep with excessive daytime sleepiness, representing a safety risk to themselves and their patients. Support NA
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Liu, Yinghui, Dong Zhen, Huibo Zhang, Hao Zhang, Zhanqun Shi i Fengshou Gu. "Vibration Response of the Planetary Gears with a Float Sun Gear and Influences of the Dynamic Parameters". Shock and Vibration 2020 (4.08.2020): 1–17. http://dx.doi.org/10.1155/2020/8886066.
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Planetary gearboxes are widely used in mechanical transmission systems due to their large transmission ratio and high transmission efficiency. In a planetary gearbox, the sun gear is usually set to float to balance the sharing of loads among planet gears. However, this floating set will result in the variation of pressure angle, overlap ratio, and meshing phase in the meshing progress and when gear faults occur, the variation will be enlarged. In the previous studies, these parameters were reduced to constant. To study the influence of the dynamic parameters on the vibration response of planetary gearboxes under different operating conditions, a new lumped-parameter model containing the time-varying pressure angle (TVPA), time-varying overlap ratio (TVOR), and time-varying meshing phase (TVMP) is established. Based on this model, the vibration response mechanism of the sun gear is analyzed. Moreover, the comparison with the previous model is made and the rule of phase modulation caused by these dynamic parameters is revealed. By comparing the dynamic responses under different loads and rotation speeds, the phase modulation is studied in detail. Finally, the sun gear fault is introduced, and the phase modulation is analyzed in different fault degrees. This study can provide theoretical reference for the condition monitoring and fault diagnosis of planetary gearbox based on vibration analysis.
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Raschepkin, A. P., I. P. Kondratenko, O. M. Karlov i R. S. Kryshchuk. "MAGNETO-ELECTRIC ENERGY CONVERTER OF SEA WAVES". Tekhnichna Elektrodynamika 2021, nr 4 (17.06.2021): 25–34. http://dx.doi.org/10.15407/techned2021.04.025.
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To convert the energy of sea waves, the use of cylindrical (with a radial magnetic flux) three-phase magnetoelectric generators with a permanent magnet rotor using a mechanical gearbox to increase the rotor speed is considered. Given the real rotor motion, a mathematical model has been developed to calculate the distribution of magnetic fields in the gap of the generator, and functional dependences of the flux linkage of the winding and the electromagnetic moment of the generator on its design and the parameters of permanent magnets have been obtained. For the adopted design, the electromagnetic moment, the distribution of phase currents in the windings, the power and voltage of the generator are determined. A comparison is made of the energy performance of generators with a traditional float drive and using a ratchet to ensure one-sided rotation of the rotor. The expediency of using a ratchet generator to convert the energy of sea waves is considered. References 6, figures 7.
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Dooley, J., N. T. Nuhfer i M. De Graef. "Lorentz observation of magnetic domains in terfenol-d". Proceedings, annual meeting, Electron Microscopy Society of America 53 (13.08.1995): 482–83. http://dx.doi.org/10.1017/s0424820100138786.
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Terfenol (Tb.27Dy.73Fe1.95) has the largest known room-temperature magnetostriction coefficient, making it well suited for low frequency, high power sonar applications. Terfenol takes the MgCu2 cubic Laves phase structure, with lattice parameter a = 0.732 nm and space group Fd3m. Magnetic domain configurations in this material are generally interpreted as 71° and 109° walls, along with 180° walls, with the magnetization along the 〈111〉 directions. At room temperature the cubic unit cell experiences an extremely small rhombohedral distortion along the magnetically soft 〈111〉 directions (e.g., the cubic [100] tilts by 1.13 mrad toward a new orientation). The growth direction, designated [11], is taken as a reference throughout this discussion.The material, prepared by a free-standing float-zone (FSZ) technique, was provided by Etrema Products Inc. in the form of [11] oriented rods with a diameter of 3 mm. Since the growth direction is perpendicular to [111] and the growth front is dendritic, growth twins are easily formed by a 180° rotation on the (111) plane.
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Walck, Scott D. "Preparing Powders For Electron Diffraction Studies". Microscopy Today 8, nr 9 (listopad 2000): 37. http://dx.doi.org/10.1017/s1551929500059472.
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Questions often come up concerning the best way to prepare powders for electron diffraction analysis in the TEM. This is actually fairly simple:1) Take an oxide powder, grind it up with mortar and pestie and take a carbon coated grid and swipe it across the fnes. Two glass slides can also use to grind up the powder.2) A number of materials can be evaporated onto a carbon coated grid or onto a cleaved NaCI sample and then float that off on water onto a grid.3) A molybdenum wire can be smoked in air to provide crys tals. If the wire is left in the smoke long enough, there will probably be enough crystal to cover a grid. Heat the wire across the terminals of an evaporator or heat with a torch to generate the white smoke. Thus MoO3 sample will pro- vide a good rotation calibration sample. Magnesium can also be burned to produce MgO crystals.
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Li, Xingxing, Hongmin Zhang, Keke Zhang, Yongqiang Yuan, Wei Zhang i Yujie Qin. "Earth Rotation Parameters Estimation Using GPS and SLR Measurements to Multiple LEO Satellites". Remote Sensing 13, nr 15 (3.08.2021): 3046. http://dx.doi.org/10.3390/rs13153046.
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Earth rotation parameters (ERP) are one of the key parameters in realization of the International Terrestrial Reference Frames (ITRF). At present, the International Laser Ranging Service (ILRS) generates the satellite laser ranging (SLR)-based ERP products only using SLR observations to Laser Geodynamics Satellite (LAGEOS) and Etalon satellites. Apart from these geodetic satellites, many low Earth orbit (LEO) satellites of Earth observation missions are also equipped with laser retroreflector arrays, and produce a large number of SLR observations, which are only used for orbit validation. In this study, we focus on the contribution of multiple LEO satellites to ERP estimation. The SLR and Global Positioning System (GPS) observations of the current seven LEO satellites (Swarm-A/B/C, Gravity Recovery and Climate Experiment (GRACE)-C/D, and Sentinel-3A/B) are used. Several schemes are designed to investigate the impact of LEO orbit improvement, the ERP quality of the single-LEO solutions, and the contribution of multiple LEO combinations. We find that ERP estimation using an ambiguity-fixed orbit can attain a better result than that using ambiguity-float orbit. The introduction of an ambiguity-fixed orbit contributes to an accuracy improvement of 0.5%, 1.1% and 15% for X pole, Y pole and station coordinates, respectively. In the multiple LEO satellite solutions, the quality of ERP and station coordinates can be improved gradually with the increase in the involved LEO satellites. The accuracy of X pole, Y pole and length-of-day (LOD) is improved by 57.5%, 57.6% and 43.8%, respectively, when the LEO number increases from three to seven. Moreover, the combination of multiple LEO satellites is able to weaken the orbit-related signal existing in the single-LEO solution. We also investigate the combination of LEO satellites and LAGEOS satellites in the ERP estimation. Compared to the LAGEOS solution, the combination leads to an accuracy improvement of 0.6445 ms, 0.6288 ms and 0.0276 ms for X pole, Y pole and LOD, respectively. In addition, we explore the feasibility of a one-step method, in which ERP and the orbit parameters are jointly determined, based on SLR and GPS observations, and present a detailed comparison between the one-step solution and two-step solution.
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Wang, Shi Jie, Xun Zhu i Zhen Dong Gao. "Research and Application of Level Rotational Construction Technology of DWT Cable-Stayed Bridge". Advanced Materials Research 163-167 (grudzień 2010): 2262–66. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.2262.
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Rotational construction for bridges attracts much attention of people because it is featured by its low initial cost, fast and easy operation and minimum traffic interruption. Nowadays, rotational bridges have been mostly built by the level rotation method of the ring combining with ball joints at home and abroad, which is more safe and easy to control the closed precision, but the large rotating friction restrict the promotion of the rotational weight and span. The author takes flat hinge supported by single point as the rotating bearing type, using embedded four fluorine board, controlling wheel construction precision strictly. In that case, Suifen He cabl-stayed bridge, weigh up to to 14000t, has been successfully complished rotational construction with the help of continuous jack. The built bridge axis deviation is limited within 3mm, and maximum deck height deviation is only 12mm. It is proved that rotational construction of flat hinge joints supported by single point can efficiently solve the colsed accuracy which is difficult to control and problems of heavy rotating traction, as long as the installation precision and the sliding performance can be controlled.
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G Giovanelli, Ronald. "The Sunspot Cycle and Solar Magnetic Fields. I. The Mechanism as Inferred from Observation". Australian Journal of Physics 38, nr 6 (1985): 1045. http://dx.doi.org/10.1071/ph851045.
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Observations of solar magnetic and velocity fields can be used to derive the course of events involved in the solar cycle. These differ in three important respects from those of conventional dynamo theories: (i) Polar field reversal. Following the outbreak of a new cycle, magnetic flux released by sunspots diffuses initially by Leighton's random-walk process, but this is soon dominated by the observed poleward flow of about 20 m s - 1 which carries flux to polar regions in about 12 months. Since follower spots lie about 2� higher in latitude than leaders, follower flux arrives in polar regions some two weeks ahead of leader flux, providing a net inflow of follower polarity there until sunspot maximum, reversing the polar field from the previous sunspot cycle and building it up to a maximum. After sunspot maximum, the flux arriving in polar regions is predominantly of follower polarity until or unless spots occur at latitudes so low that flux can diffuse towards and across the equator, predominantly from the lower latitude leader; the effect is doubled by a complementary migration from the opposite hemisphere. This prevents the change in polar flux over the cycle from dropping to zero, and leaves the polarity there reversed at the end of the cycle. (ii) The sunspot cycle. A slow, deeper counterflow, essential for continuity, carries flux strands down in the polar zones and then equatorwards. The concentration of strands is increased continually by differential rotation, and they are dragged continually into contact. Reconnection occurs rapidly except between tubes that are inclined at very small angles. This results in the formation of ropes of flux strands twisted very gently. At some stage they are large enough to float, forming sunspots. The mean sunspot latitude decreases continuously as the flux is carried equatorwards, dying out as the flux ropes become exhausted. The whole process repeats, once again reversing the polar and spot group magnetic fields. Hale's polarity laws follow immediately, and Sporer's law requires only minor adjustments to the predicted velocity of the deep equatorward counterflow. The estimated velocity of this flow is compatible with the observed sunspot and magnetic cycles of 11 and 22 years. (iii) The torsional oscillation. Shear by differential rotation increases the concentration of flux strands; the reaction to strongly sheared flux strands is a tendency to reduce differential rotation. This results in cyclic variations of differential rotation, the phase with respect to sunspot formation being in good agreement with the torsional oscillation observations of Howard and LaBonte (1981) at all latitudes up to 50-55�.
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Fritzewski, D. J., S. A. Barnes, D. J. James i K. G. Strassmeier. "The rotation period distribution of the rich Pleiades-age southern open cluster NGC 2516". Astronomy & Astrophysics 641 (wrzesień 2020): A51. http://dx.doi.org/10.1051/0004-6361/201936860.
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Aims. We wish to measure the cool star rotation period distribution for the Pleiades-age rich open cluster NGC 2516 and use it to determine whether cluster-to-cluster variations exist in otherwise identical open clusters. Methods. We obtained 42 d-long time-series CCD photometry of NGC 2516 in the V and Ic filters using the Yale 1 m telescope at CTIO and performed a number of related analyses, including PSF-based time-series photometry. Our data are complemented with additional information from several photometric datasets, literature radial velocities, and Gaia DR2 astrometry. All available data are used to construct an integrated membership list for NGC 2516, containing 844 stars in our ≈1° field of view. Results. We derived 308 rotation periods for late-F to mid-M cluster members from our photometry. We identified an additional 247 periodic M dwarf stars from a prior study as cluster members, and used these to construct a 555-star rotation period distribution for NGC 2516. The colour-period diagram (in multiple colours) has almost no outliers and exhibits the anticipated triangular shape, with a diagonal slow rotator sequence that is preferentially occupied by the warmer stars along with a flat fast rotator sequence that is preferentially populated by the cooler cluster members. We also find a group of extremely slowly rotating M dwarfs (10 d ≲ Prot ≲ 23 d), forming a branch in the colour-period diagram which we call the “extended slow rotator sequence”. This, and other features of the rotational distribution can also be found in the Pleiades, making the colour-period diagrams of the two clusters nearly indistinguishable. A comparison with the well-studied (and similarly aged) open cluster M 35 indicates that the cluster’s rotational distribution is also similarly indistinguishable from that of NGC 2516. Those for the open clusters M 50 and Blanco 1 are similar, but data issues for those clusters make the comparisons somewhat more ambiguous. Nevertheless, we demonstrate the existence of a representative zero-age main sequence rotational distribution and provide a simple colour-independent way to represent it. We perform a detailed comparison of the NGC 2516 rotation period data with a number of recent rotational evolution models. Using X-ray data from the literature, we also construct the first rotation-activity diagram for solar-type stars in NGC 2516, one that we find is essentially indistinguishable from those for the Pleiades and Blanco 1. Conclusions. The two clusters NGC 2516 and Pleiades can be considered twins in terms of stellar rotation and related properties (and M 35, M 50, and Blanco 1 are similar), suggesting that otherwise identical open clusters also have intrinsically similar cool star rotation and activity distributions.
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Espinosa Peralta, Paul, Manuel Ferre i Miguel Ángel Sánchez-Urán. "Robust Fastener Detection Based on Force and Vision Algorithms in Robotic (Un)Screwing Applications". Sensors 23, nr 9 (6.05.2023): 4527. http://dx.doi.org/10.3390/s23094527.
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This article addresses how to tackle one of the most demanding tasks in manufacturing and industrial maintenance sectors: using robots with a novel and robust solution to detect the fastener and its rotation in (un)screwing tasks over parallel surfaces with respect to the tool. To this end, the vision system is based on an industrial camera with a dynamic exposure time, a tunable liquid crystal lens (TLCL), and active near-infrared reflectance (NIR) illumination. Its camera parameters, combined with a fixed value of working distance (WD) and variable or constant field of view (FOV), make it possible to work with a variety of fastener sizes under several lighting conditions. This development also uses a collaborative robot with an embedded force sensor to verify the success of the fastener localization in a real test. Robust algorithms based on segmentation neural networks (SNN) and vision were developed to find the center and rotation of the hexagon fastener in a flawless condition and worn, scratched, and rusty conditions. SNNs were tested using a graphics processing unit (GPU), central processing unit (CPU), and edge devices, such as Jetson Javier Nx (JJNX), Intel Neural Compute Stick 2 (INCS2), and M.2 Accelerator with Dual Edge TPU (DETPU), with optimization parameters, such as the unsigned integer (UINT) and float (FP), to understand their performance. A virtual program logic controller (PLC) was mounted on a personal computer (PC) as the main control to process the images and save the data. Moreover, a mathematical analysis based on the international standard organization (ISO) and patents of the manual socket wrench was performed to determine the maximum error allowed. In addition, the work was substantiated using exhaustive evaluation tests, validating the tolerance errors, robotic forces for successfully completed tasks, and algorithms implemented. As a result of this work, the translation tolerances increase with higher sizes of fasteners from 0.75 for M6 to 2.50 for M24; however, the rotation decreases with the size from 5.5° for M6 to 3.5° for M24. The proposed methodology is a robust solution to tackle outliers contours and fake vertices produced by distorted masks present in non-constant illumination; it can reach an average accuracy to detect the vertices of 99.86% and the center of 100%, also, the time consumed by the SNN and the proposed algorithms is 73.91 ms on an Intel Core I9 CPU. This work is an interesting contribution to industrial robotics and improves current applications.
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YASUDA, TAKAHIRO, i YASUNARI TAKANO. "THE STUDY OF THE UNSTEADY FLUID-DYNAMIC FORCES ACTING ON AN AUTO ROTATING ELLIPTIC CYLINDER". Modern Physics Letters B 19, nr 28n29 (20.12.2005): 1675–78. http://dx.doi.org/10.1142/s0217984905010190.
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When a thin flat pate is released in the still air, the plate may fall aslant and automatically set into a rotational motion. This phenomenon is called autorotation. In this state, the unsteady fluid-dynamic forces act on the plate due to the vortex shedding and the rotation of the body. In this study, we focused on the auto-rotating phenomenon of an elliptic cylinder and investigated the effect of the cylinder rotation on the unsteady fluid-dynamic forces by the comparison between the result of the complex velocity potential theory and the one of numerical simulation. It was found that the low drag occurring at -160 degree phase and the high lift at zero degree phase are caused by the cylinder rotation.
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Bashmachnikov, I., D. Boutov i J. Dias. "Manifestation of two meddies in altimetry and sea-surface temperature". Ocean Science Discussions 9, nr 5 (27.09.2012): 3071–95. http://dx.doi.org/10.5194/osd-9-3071-2012.
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Abstract. Two meddies were identified in the Iberian Basin using shipboard ADCP (Meddy 1) and ARGO float (Meddy 2) in contrasting background conditions. Meddy 1 was observed while interacting with the Azores current (AzC) while Meddy 2 was observed rather far north from the AzC jet, in much calmer dynamical background. In both cases the meddies produced a clear anticyclonic surface signal, detectable in altimetry as well as in sea-surface temperature (SST). Analysis of the in-situ observations of the dynamic signal over Meddy 1 showed that the signal, generated by the moving meddy, dominated the AzC dynamics at least up to the base of the seasonal thermocline even at the late stages of its interaction with the jet. The center of rotation of the surface signal was shifted south-westward from the axis of the meddy by about 18 km, and its dynamic radius was 2 times bigger than that of the meddy. The SST anomalies in the core of the surface signals were negative in contrast to the positive SST anomalies in surface anticyclones generated by meandering surface currents. The later difference gives ground for identification of meddies (as well as other sub-surface anticyclones) using coupled altimetry – SST remote sensing data. An identification of Meddy 1 previous to the shipboard ADCP measurements was the first successful experience. At the same time, SST anomalies over both meddies were rather weak, often unstable and statistically significant only over periods of months.
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López, L. A., Omar Pedraza i V. E. Ceron. "Time-dependent solution from Myers–Perry". Canadian Journal of Physics 94, nr 2 (luty 2016): 177–79. http://dx.doi.org/10.1139/cjp-2015-0354.
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We present a three-parameter time-dependent solution of the vacuum Einstein equations in five dimensions. The solution is obtained by applying the Wick rotation to the Myers–Perry solution that represents a rotating black hole in five dimensions. The new interpretation of the Myers–Perry solution can be considered among the generalized Einstein–Rosen type that can be interpreted as plane-symmetric waves, cylindrical waves or cosmological space–time in five dimensions. In some limits the solution has boost-rotational symmetry and it is asymptotically flat. In the case that the solution represents a cylindrical space–time, the E-energy is analyzed.
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Sweeney, Alison, Alyssa Stephany, Shari Whicker, Jack Bookman i David A. Turner. "Senior Pediatric Residents as Teachers for an Innovative Multidisciplinary Mock Code Curriculum". Journal of Graduate Medical Education 3, nr 2 (1.06.2011): 188–95. http://dx.doi.org/10.4300/jgme-d-10-00212.1.
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Abstract Background Resuscitation education for pediatric residents may be limited due to the low frequency of actual codes in children. Mock codes represent an opportunity to increase trainee education in acute resuscitations, and we designed a unique multidisciplinary mock code curriculum that uses senior pediatric residents as teachers. Methods A novel mock code curriculum was designed and integrated into an existing night-float rotation. Our 2-tiered curriculum not only focuses on improving teaching proficiency for resident educators (REs) but also includes separate goals to augment simulation-based resuscitation education for resident participants (RPs) and the multidisciplinary staff. Results Seventy-six residents (17 REs, 59 RPs) and more than 75 nurses have participated in the curriculum. After participation, 100% of residents felt that this curriculum would improve the quality of actual resuscitations, and 94% of RPs reported receiving valuable feedback. Comfort with teaching and feedback increased for REs (P < .05), and comfort in resuscitation and crisis resource management improved for RPs (P < .05). The nursing staff also felt that communication, teamwork, and collaboration improved due to implementation of this curriculum. Conclusions A unique mock code curriculum can improve resident comfort with teaching, peer facilitation, feedback, and resuscitation. Curricular interventions of this nature may also be able to improve the balance between service and education within a residency training program. As we move toward a competency based training model within graduate medical education, further investigation is needed to link educational modifications of this nature to clinical outcomes and actual resident performance.
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Bashmachnikov, I., D. Boutov i J. Dias. "Manifestation of two meddies in altimetry and sea-surface temperature". Ocean Science 9, nr 2 (5.03.2013): 249–59. http://dx.doi.org/10.5194/os-9-249-2013.
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Abstract. Two meddies were identified in the Iberian Basin using shipboard ADCP (Meddy 1) and Argo float (Meddy 2) in contrasting background conditions. Meddy 1 was observed while interacting with the Azores Current (AzC), while Meddy 2 was observed in a much calmer dynamical background, north from the AzC jet. In both cases the meddies formed a clear anticyclonic surface signal, detectable in altimetry as well as in sea-surface temperature (SST). Analysis of the in situ observations of the dynamic signal over Meddy 1 showed that the signal, generated by the moving meddy, dominated the AzC dynamics at least up to the base of the seasonal thermocline even at the late stages of its interaction with the jet. The centre of rotation of the surface signal was shifted south-westward from the axis of the meddy by about 18 km, and its dynamic radius was 2 times bigger than that of the meddy. In the centre of the anticyclonic surface signals of both meddies, SST was colder than that of the surrounding water, in contrast to warm SST anomalies in the cores of surface anticyclones generated by meandering surface currents. The latter difference gives ground for identification of meddies (as well as other sub-surface anticyclones) in comparatively dynamically calm regions using coupled altimetry–SST remote sensing data. An identification of Meddy 1 prior to the shipboard ADCP measurements was the first successful experience. At the same time, SST anomalies over the meddies were rather weak, often unstable and statistically significant only over periods of months.
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D., Ünsalan. "A wave energy system based on peristaltic pumping of air by sea waves". Scientific Bulletin of Naval Academy XXII, nr 1 (15.07.2019): 269–77. http://dx.doi.org/10.21279/1454-864x-19-i1-040.
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Oscillating water column type of wave energy converters have attracted researchers and engineers working on the field of renewable energy systems, despite the problems caused by the alternating direction of air flow through the turbines. This problem has been circumvented by the use of single direction of rotation turbines such as Wells, Denniss-Auld and omnidirectional impulse turbines, albeit with rather low efficiencies. The authors have considered the usage of near-sinusoidal (cnoidal) form of sea waves as the drivers for the linear peristaltic pumping of air along a channel. The conceived device is an inverted U-shaped channel on a barge, aligned in the direction of wave and serves as a channel for the progress of waveform. Air is driven through the channel by peristaltic action to achieve a unidirectional air flow at the leeward end of the channel. An end-wall operated by a float experiencing heaving and surging motions at the leeward side of the channel prevents the escape of pumped air, which instead is directed to an upward duct leading to a turbine. Since the air flow is unidirectional, the use of more convenient air turbines compared to the ones used in oscillating water column devices are enabled. Air flow parameters with wave amplitudes exceeding and less than channel height above the calm water line are analysed using the Airy wave to demonstrate the feasibility of the proposed system analytically. It was found that the optimum solution was achieved when the channel top is at the calm water level
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Thomas, Leif N., John R. Taylor, Eric A. D’Asaro, Craig M. Lee, Jody M. Klymak i Andrey Shcherbina. "Symmetric Instability, Inertial Oscillations, and Turbulence at the Gulf Stream Front". Journal of Physical Oceanography 46, nr 1 (styczeń 2016): 197–217. http://dx.doi.org/10.1175/jpo-d-15-0008.1.
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AbstractThe passage of a winter storm over the Gulf Stream observed with a Lagrangian float and hydrographic and velocity surveys provided a unique opportunity to study how the interaction of inertial oscillations, the front, and symmetric instability (SI) shapes the stratification, shear, and turbulence in the upper ocean under unsteady forcing. During the storm, the rapid rise and rotation of the winds excited inertial motions. Acting on the front, these sheared motions modulate the stratification in the surface boundary layer. At the same time, cooling and downfront winds generated a symmetrically unstable flow. The observed turbulent kinetic energy dissipation exceeded what could be attributed to atmospheric forcing, implying SI drew energy from the front. The peak excess dissipation, which occurred just prior to a minimum in stratification, surpassed that predicted for steady SI turbulence, suggesting the importance of unsteady dynamics. The measurements are interpreted using a large-eddy simulation (LES) and a stability analysis configured with parameters taken from the observations. The stability analysis illustrates how SI more efficiently extracts energy from a front via shear production during periods when inertial motions reduce stratification. Diagnostics of the energetics of SI from the LES highlight the temporal variability in shear production but also demonstrate that the time-averaged energy balance is consistent with a theoretical scaling that has previously been tested only for steady forcing. As the storm passed and the winds and cooling subsided, the boundary layer restratified and the thermal wind balance was reestablished in a manner reminiscent of geostrophic adjustment.
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Braeck, Simen. "Inertial Frame Dragging and Relative Rotation of ZAMOs in Axistationary Asymptotically Flat Spacetimes". Universe 9, nr 3 (26.02.2023): 120. http://dx.doi.org/10.3390/universe9030120.
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In axistationary, asymptotically flat spacetimes, zero angular momentum observers (ZAMOs) define an absolute standard of non-rotation locally, as can be verified by the absence of any Sagnac effect for these observers. Nevertheless, we argue that on a global scale the only physically meaningful concept is that of relative rotation. The argument is substantiated by solving Einstein’s equations for an approximate thin shell model, where we maintain a degree of freedom, by relaxing the natural assumption of vanishing rotation at asymptotic infinity, at the outset of the analysis. The solution reveals that Einstein’s equations only determine differences in the rotation rate of ZAMOs, thereby establishing the concept of relative rotation globally. The interpretation of rotation as relative in a global context is inherently linked to the freedom to transform between coordinate systems rotating relative to each other, implying that an arbitrary ZAMO located at any radius may claim to be the one that is non-rotating on a global scale, and that the notion of an asymptotic Lorentz frame relative to which one may measure absolute rotation is devoid of any meaning. The concept of rotation in Kerr spacetime is then briefly discussed in the context of this interpretation.
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Stamm, Stacy E., i Loren Z. F. Chiu. "Calcaneal Plantar Flexion During the Stance Phase of Gait". Journal of Applied Biomechanics 32, nr 2 (kwiecień 2016): 205–9. http://dx.doi.org/10.1123/jab.2015-0044.
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When the rear- and forefoot are constrained, calcaneal plantar flexion may occur, deforming the longitudinal arch. Previous research has reported calcaneal motion relative to the tibia or forefoot; these joint rotations may not accurately describe rotation of the calcaneus alone. This investigation: (1) characterized the calcaneus and leg segment and ankle joint rotations during stance in gait, and (2) described the range of calcaneal plantar flexion in different structural arch types. Men (n = 14) and women (n = 16) performed gait in a motion analysis laboratory. From heel strike to heel off, the leg rotated forward while the calcaneus plantar flexed. Before foot flat, calcaneal plantar flexion was greater than forward leg rotation, resulting in ankle plantar flexion. After foot flat, forward leg rotation was greater than calcaneal plantar flexion, resulting in ankle dorsiflexion. Structural arch type was classified using the longitudinal arch angle. The range of calcaneal plantar flexion from foot flat to heel off was small in low (−2° to −8°), moderate in high (−3° to −12°), and large in normal (−2° to −20°) structural arches. Calcaneal plantar flexion in gait during midstance may reflect functional arch characteristics, which vary depending on structural arch type.
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Bach, B., E. C. Linnartz, M. H. Vested, A. Andersen i T. Bohr. "From Newton’s bucket to rotating polygons: experiments on surface instabilities in swirling flows". Journal of Fluid Mechanics 759 (24.10.2014): 386–403. http://dx.doi.org/10.1017/jfm.2014.568.
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AbstractWe present an experimental study of ‘polygons’ forming on the free surface of a swirling water flow in a partially filled cylindrical container. In our set-up, we rotate the bottom plate and the cylinder wall with separate motors. We thereby vary rotation rate and shear strength independently and move from a rigidly rotating ‘Newton’s bucket’ flow to one where bottom and cylinder wall are rotating oppositely and the surface is strongly turbulent but flat on average. Between those two extremes, we find polygonal states for which the rotational symmetry is spontaneously broken. We investigate the phase diagram spanned by the two rotational frequencies at a given water filling height and find polygons in a regime, where the two frequencies are sufficiently different and, predominantly, when they have opposite signs. In addition to the extension of the family of polygons found with the stationary cylinder, we find a new family of smaller polygons for larger rotation rates of the cylinder, opposite to that of the bottom plate. Further, we find a ‘monogon’, a figure with one corner, roughly an eccentric circle rotating in the same sense as the cylinder. The case where only the bottom plate is rotating is compared with the results of Jansson et al. (Phys. Rev. Lett., vol. 96, 2006, art. 174502), where the same size of cylinder was used, and although the overall structure of the phase diagram spanned by water height and rotational frequency is the same, many details are different. To test the effect of small experimental defects, such as misalignment of the bottom plate, we investigate whether the rotating polygons are phase locked with the bottom plate, and although we find cases where the frequency ratio of figure and bottom plate is nearly rational, we do not find phase locking. Finally, we show that the system has a surprising multistability and excitability, and we note that this can cause quantitative differences between the phase diagrams obtained in comparable experiments.
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Camci, C., i B. Glezer. "Liquid Crystal Thermography on the Fluid Solid Interface of Rotating Systems". Journal of Heat Transfer 119, nr 1 (1.02.1997): 20–29. http://dx.doi.org/10.1115/1.2824095.
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Liquid crystal thermography is an effective method widely employed in transient and steady-state heat transfer experiments with excellent spatial resolution and good accuracy. Most of the past studies in liquid crystal thermography deal with stationary conditions. The present investigation deals with the influence of rotation on the color response of encapsulated liquid crystals attached to a flat rotating surface. A general methodology developed for the application of thermochromic liquid crystals in rotating systems is described for the first time. The investigation is performed for a rotational speed range from 0 to 7500 rpm using two different coatings displaying red at 30° and 45°C, under stationary conditions. Local liquid crystal color on the surface of a rotating disk is correlated with local temperature as measured by a non-intrusive infrared sensor at various rotational speeds. An immediate observation from the present study is that the color response (hue) of encapsulated liquid crystals is not altered by either the centrifugal acceleration of the rotating environment or the aerodynamic friction force at the rotating disk-air interface. Present investigation also shows that when a stroboscope light is introduced, the color response is not significantly altered due to additional periodic illumination. A complete and general experimental methodology including rotating surfaces with non-axisymmetric temperature distribution is presented. Results from the current liquid crystal technique agree well with the theoretical adiabatic temperature rise of a free rotating disk as predicted by an analytical method.