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Search Results: 1 - 10 of 144469 matches for " F. Plesescu "
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Fiber-Optic-Gyroscope Measurements Close to Rotating Liquid Helium
M. Tajmar,F. Plesescu
Physics , 2009, DOI: 10.1063/1.3326250
Abstract: We previously reported anomalous fiber-optic gyroscope signals observed above rotating rings at temperatures close to liquid helium. Our results suggested that the liquid helium itself may be the source of our observed phenomenon. We constructed a new cryostat experiment that allows rotating a large quantity of liquid helium together with a superconducting niobium tube. The facility is built in such a way that our gyroscope can be placed directly in the center of rotation along the axis; however, the cryostat is built around the gyroscope to allow measuring without interference of helium liquid or gas. An anomalous signal was found of similar value compared to our previous measurements with a changed sign. As this measurement was done at a different location (center position) with respect to our old setup (top position), first hints for a possible field distribution of this phenomenon can be made. However, due to lower angular velocities used in this new setup so far, our measurement resolution was close to three times the resolution of our gyroscope and hence our data represent work in progress.
Anomalous Fiber Optic Gyroscope Signals Observed above Spinning Rings at Low Temperature
M. Tajmar,F. Plesescu,B. Seifert
Physics , 2008, DOI: 10.1088/1742-6596/150/3/032101
Abstract: Precision fiber optic gyroscopes were mounted mechanically de-coupled above spinning rings inside a cryostat. Below a critical temperature (typically <30 K), the gyroscopes measure a significant deviation from their usual offset due to Earth's rotation. This deviation is proportional to the applied angular ring velocity with maximum signals towards lower temperatures. The anomalous gyroscope signal is about 8 orders of magnitude smaller then the applied angular ring velocity, compensating about one third of the Earth rotation offset at an angular top speed of 420 rad/s. Moreover, our data shows a parity violation as the effect appears to be dominant for rotation against the Earth's spin. No systematic effect was found to explain this effect including the magnetic environment, vibration and helium gas friction suggesting that our observation is a new low temperature phenomenon. Tests in various configurations suggest that the rotating low temperature helium may be the source of our anomalous signals.
Search for Frame-Dragging-Like Signals Close to Spinning Superconductors
M. Tajmar,F. Plesescu,B. Seifert,R. Schnitzer,I. Vasiljevich
Physics , 2007,
Abstract: High-resolution accelerometer and laser gyroscope measurements were performed in the vicinity of spinning rings at cryogenic temperatures. After passing a critical temperature, which does not coincide with the material's superconducting temperature, the angular acceleration and angular velocity applied to the rotating ring could be seen on the sensors although they are mechanically de-coupled. A parity violation was observed for the laser gyroscope measurements such that the effect was greatly pronounced in the clockwise-direction only. The experiments seem to compare well with recent independent tests obtained by the Canterbury Ring Laser Group and the Gravity-Probe B satellite. All systematic effects analyzed so far are at least 3 orders of magnitude below the observed phenomenon. The available experimental data indicates that the fields scale similar to classical frame-dragging fields. A number of theories that predicted large frame-dragging fields around spinning superconductors can be ruled out by up to 4 orders of magnitude.
Measurement of Gravitomagnetic and Acceleration Fields Around Rotating Superconductors
M. Tajmar,F. Plesescu,B. Seifert,K. Marhold
Physics , 2006, DOI: 10.1063/1.2437552
Abstract: It is well known that a rotating superconductor produces a magnetic field proportional to its angular velocity. The authors conjectured earlier, that in addition to this so-called London moment, also a large gravitomagnetic field should appear to explain an apparent mass increase of Niobium Cooper-pairs. A similar field is predicted from Einstein's general relativity theory and the presently observed amount of dark energy in the universe. An experimental facility was designed and built to measure small acceleration fields as well as gravitomagnetic fields in the vicinity of a fast rotating and accelerating superconductor in order to detect this so-called gravitomagnetic London moment. This paper summarizes the efforts and results that have been obtained so far. Measurements with Niobium superconductors indeed show first signs which appear to be within a factor of 2 of our theoretical prediction. Possible error sources as well as the experimental difficulties are reviewed and discussed. If the gravitomagnetic London moment indeed exists, acceleration fields could be produced in a laboratory environment.
Experimental Detection of the Gravitomagnetic London Moment
M. Tajmar,F. Plesescu,K. Marhold,C. J. de Matos
Physics , 2006,
Abstract: It is well known that a rotating superconductor produces a magnetic field proportional to its angular velocity. The authors conjectured earlier, that in addition to this so-called London moment, also a large gravitomagnetic field should appear to explain an apparent mass increase of Niobium Cooper-pairs. This phenomenon was indeed observed and induced acceleration fields outside the superconductor in the order of about 10^-4 g were found. The field appears to be directly proportional to the applied angular acceleration of the superconductor following our theoretical motivations. If confirmed, a gravitomagnetic field of measurable magnitude was produced for the first time in a laboratory environment. These results may open up a new experimental window on testing general relativity and its consequences using coherent matter.
Evaluating the Relationship between the Banking System Stability and the Internal Capital Adequacy Assessment Process: Evidence from the Egyptian Banking Sector  [PDF]
Karim F. F. Mohamed
Journal of Financial Risk Management (JFRM) , 2018, DOI: 10.4236/jfrm.2018.74020
Abstract: In the repercussions of the latest financial crisis that have occurred on the years 2008-2009, to fortify the stability of the banking systems, policy makers, and the Basel Committee on Banking Supervision—BCBS, together with national regulators have built up a few safety measures, and structures to guarantee that banks establishments keep up adequate capital levels through using risk management tools, in specific the Internal Capital Adequacy Assessment Processes (ICAAP). They all have called for thorough evaluations and assessments for the structure and components of risk management frameworks, tools, and practices whether by banks, regulators, analysts and risk management experts consistently, to ascertain the adequacy of the banking systems, policies, arrangements and techniques for overseeing risks, and guaranteeing the sufficiency of holding appropriate capital levels for confronting normal, as well as adverse and unexpected situations or emergencies. The main objectives of this research study are to shed the light on the ICAAP as one of the main keys of risk management programs, a process by which banks can use to ensure that they operate with an appropriate level of capital, forward looking processes for capital planning covering a broad range of risks across banks, activities beyond simple capital management, and bring together risk and capital management activities in a form that can be used to support business decisions. The research study shall evaluate the significant relationship between the Banking System Stability (dependent variable) and the Internal Capital Adequacy Assessment Process (ICAAP—independent variable) with evidence from the Egyptian Banking Sector.
Creation and Analysis of Earth’s Surface Roughness Maps from Airborne LiDAR Measurements in Downtown Urban Landscape  [PDF]
Fahmy F. F. Asal
Journal of Geographic Information System (JGIS) , 2019, DOI: 10.4236/jgis.2019.112015
Abstract: The Earth’s surface roughness constitutes an important parameter in terrain analysis for studying different environmental and engineering problems. Authors gave different definitions and measures for the earth’s surface roughness that usually depend on exploitation of digital elevation data for its reliable determination. This research aimed at exploring the different approaches for defining and extraction of the Earth’s surface roughness from Airborne LiDAR Measurements. It also aimed at evaluating the effects of the window size of the standard deviation filter on the created roughness maps in downtown landscapes using three known approaches namely; standard deviation filtering of the Digital Elevation Model (DEM), standard deviation filtering of the slope gradient model and standard deviation filtering of the profile curvature model. In this context, different roughness maps have been created from Airborne LiDAR measurements of the City of Toronto, Canada using the three filtering approaches with varying window sizes. Visual analysis has shown color tones of small roughness values with smooth textures dominate the roughness maps from small window sizes of the standard deviation filter, however, increasing the window sizes has produced wider variations of the color tones and rougher texture roughness maps. The standard deviations and ranges of the roughness maps from LiDAR DEM have increased due to increasing the filter window size while the skewness and kurtosis have decreased due to increasing the window size, indicating that the roughness maps from larger window sizes are statistically more symmetrical and more consistent. Thus, kurtosis has decreased by 53% and 82% due to increasing the window size to 7 × 7 and 15 × 15 respectively. The standard deviations of the roughness maps from the slope gradient model have increased due to increasing the window size till 15 × 15 while they have decreased with more increases. However, skewness has decreased due to increasing the window size till 15 × 15 and the kurtosis has decreased with higher rate till window size of 11 × 11. In the roughness maps from the profile curvature model, the ranges and skewness have decreased by 93.6% and 82.6% respectively due to increasing the window size to 15 × 15 while, kurtosis has decreased by 58.6%, 76.3% and 93.76% due to increases in the filter window size to 5 × 5, 7 × 7 and 15 × 15 respectively.
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Nieuwe West-Indische Gids , 1949,
Abstract:
Kroniek
- F.
Nieuwe West-Indische Gids , 1949,
Abstract:
Kroniek
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Nieuwe West-Indische Gids , 1947,
Abstract:
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