scholarly journals Relative space: space measurements on a rotating platform

2003 ◽  
Vol 24 (6) ◽  
pp. 563-573 ◽  
Author(s):  
Matteo Luca Ruggiero
Keyword(s):  
Author(s):  
Dmitry Elkin ◽  
Dmitry Elkin ◽  
Andrey Zatsepin ◽  
Andrey Zatsepin

Laboratory investigation of eddy formation mechanism due to spatially non-uniform wind impact was fulfilled. Experiment was provided in a cylindrical and a square form tank filled with homogeneous or stratified fluid and displaced on a rotating platform. In the absence of the platform rotation, an impact of the single air jet lead to the formation of a symmetric vortex dipole structure that occupied the whole water area in the tank. In the presence of the platform rotation, a compact anticyclonic eddy was formed in a part of the dipole with anticyclonic vorticity, while in a part with cyclonic vorticity no any compact eddy was observed. The laboratory results were successfully compared with the field observation results fulfilled in the at the Black Sea coastal zone near Gelendzhik.


2020 ◽  
Vol 12 (22) ◽  
pp. 3736
Author(s):  
Gennadiy Emel’yantsev ◽  
Oleg Stepanov ◽  
Aleksey Stepanov ◽  
Boris Blazhnov ◽  
Elena Dranitsyna ◽  
...  

The paper presents the developed integrated GNSS/IMU gyrocompass which, unlike the existing systems, contains a single-axis rotating platform with two antennas installed on it and an inertial measurement unit with tactical grade fiber-optic gyros. It is shown that the proposed design provides attitude solution by observing the signals of only one navigation satellite. The structure of the integrated GNSS/IMU gyrocompass, its specific features and prototype model used in the tests are described. The given test results in urban conditions confirmed heading determination accurate to ±1.5° (3σ).


1987 ◽  
Vol 177 ◽  
pp. 381-394 ◽  
Author(s):  
Dominique P. Renouard ◽  
Gabriel Chabert D'Hières ◽  
Xuizhang Zhang

The influence of rotation upon internal solitary waves is studied in a (10 m × 2 m × 0.6 m) channel located on the large rotating platform at Grenoble University. We observe an intumescence which moves along the right-hand side of the channel with respect to its direction of propagation. Along the side, once the intumescence reaches its equilibrium shape, the height variation of the interface with time is correctly described by the sech2 function, and the characteristic KdV scaling law linking the maximum amplitude and the wavelength along the side is fulfilled. The intumescence is a stable phenomenon which moves as a whole without deformation apart from the viscous damping. For identical experimental conditions, the amplitude of the intumescence along the side increases with increasing Coriolis parameter, and at a given period of rotation of the platform, the celerity along the side increases with increasing amplitude. But for identical conditions, we found that the celerity along the side is equal to the celerity that the wave would have for such conditions without rotation. The amplitude of the intumescence in a plane perpendicular to the wall decreases exponentially with increasing distance from the side, but the crest of the wave is curved backward.


The Knee ◽  
2011 ◽  
Vol 18 (6) ◽  
pp. 496-498 ◽  
Author(s):  
Hideo Kobayashi ◽  
Yasushi Akamatsu ◽  
Naoya Taki ◽  
Hirohiko Ota ◽  
Naoto Mitsugi ◽  
...  

2009 ◽  
Vol 17 (2) ◽  
pp. 174-178 ◽  
Author(s):  
Adrian J Bauze ◽  
Mark S Falworth ◽  
Roger D Oakeshott

Purpose. To present early results of 400 consecutive low contact stress (LCS) anteroposterior (AP) glide total knee arthroplasties (TKAs) performed by a single surgeon. Methods. 304 consecutive patients aged 30 to 96 (mean, 66) years underwent 400 TKAs using LCS AP glides performed by a single surgeon. Only patients with an intact posterior cruciate ligament, a fixed flexion deformity of <15°, and a valgus deformity of <15° were included. Patients were assessed pre- and post-operatively using the American Knee Society (AKS) and Hospital for Special Surgery (HSS) scores. Range of motion was measured using a goniometer. AP and lateral radiographs were assessed for radiolucencies and osteolysis. Results. The mean follow-up period was 4.2 (range, 1–8) years. The mean fixed flexion improved to 1° from 11° and the mean active flexion improved to 120° from 111°. Both AKS and HSS scores improved significantly. There were 28 anterior soft tissue impingements; 9 of them were in the first year of the study. Thereafter, the anterior lip of the bearing was modified and any offending osteophytes, soft tissue, or fat pads were excised. Of 39 (10%) knees that underwent re-operation (16 were due to anterior soft tissue impingement), 20 (5%) did not require change of the AP glide bearing and the remaining 19 were converted to a rotating platform bearing. No patellar baja was noted after fat pad excision. No patient had catastrophic wear or failure of the polyethylene bearing. The survival rate of the AP glide bearing was 95%. Conclusion. The early-to-mid-term outcomes of the LCS AP glide TKA are promising.


2010 ◽  
Vol 92 (7) ◽  
pp. 1635-1639 ◽  
Author(s):  
John J Callaghan ◽  
Christopher W Wells ◽  
Steve S Liu ◽  
Devon D Goetz ◽  
Richard C Johnston

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Corné van Loon ◽  
Niels Baas ◽  
Verdonna Huey ◽  
James Lesko ◽  
Geert Meermans ◽  
...  

Abstract Purpose The purpose of the study was to identify the earliest time point where subjects realized the greatest clinical improvement after TKA, and the time when post-operative scores became superior to pre-operative scores. Post-hoc exploratory analyses were conducted to investigate predictors of early post-operative outcomes and patient satisfaction. Methods Six investigators across 4 sites in the Netherlands prospectively implanted 200 subjects with a contemporary cemented rotating platform device. Patient Reported Outcome Measurements (PROMs) KOOS-PS, PKIP, and EQ-5D were collected pre-operatively and post-operatively through 2-years. PROMs change from pre-operative baseline were summarized, along with radiographic outcomes and adverse events (AEs). Pre-operative patient characteristics were explored for correlation with patient outcomes, and patient satisfaction for correlation with KOOS-PS. Results Follow-up compliance was 99% at 6-months, and 95.5% at 2-years. The percentage with higher KOOS-PS compared to baseline was 81.3% at 6-months. KOOS-PS, PKIP, and PKIP subscore means were all better at 6-weeks versus baseline. Gender, BMI, hypertension, and pre-operative KOOS-PS were weakly correlated with 6-week KOOS-PS (multivariate R-squared = 14.1%), but only pre-operative KOOS-PS demonstrated correlation with post-operative KOOS-PS at 6-months or later (R-squared < 5% at 6-months and 2 years). Satisfaction was moderately correlated with concurrent KOOS-PS at each post-operative time point, with (R-squared = 35.3% at 6-months, and 37.5% at 2 years). Conclusion The greatest mean clinical improvement occurred within the first 6-weeks. Although some pre-operative factors were correlated with higher early post-operative KOOS-PS outcomes, these advantages disappeared by 6-months aside from weak correlation with pre-operative KOOS-PS. Post-operative KOOS-PS was moderately correlated with concurrent post-operative satisfaction. These results may be used for pre-operative counseling and management of patient’s postoperative expectations. Trial registration Clinicaltrials.gov, NCT02339610. Registered 15 January 2015.


Sign in / Sign up

Export Citation Format

Share Document