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Same Diameter (same + diameter)
Selected AbstractsDirection of cross-modal information transfer affects human brain activation: a PET studyEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 1 2002Ryuta Kawashima Abstract The purpose of this study was to determine the functional organization of the human brain involved in cross-modal discrimination between tactile and visual information. Regional cerebral blood flow was measured by positron emission tomography in nine right-handed volunteers during four discrimination tasks; tactile,tactile (TT), tactile,visual (TV), visual,tactile (VT), and visual,visual (VV). The subjects were asked either to look at digital cylinders of different diameters or to grasp the digital cylinders with the thumb and index finger of the right hand using haptic interfaces. Compared with the motor control task in which the subjects looked at and grasped cylinders of the same diameter, the right lateral prefrontal cortex and the right inferior parietal lobule were activated in all the four discrimination tasks. In addition, the dorsal premotor cortex, the ventral premotor cortex, and the inferior temporal cortex of the right hemisphere were activated during VT but not during TV. Our results suggest that the human brain mechanisms underlying cross-modal discrimination have two different pathways depending on the temporal order in which stimuli are presented. [source] In vitro evaluation of the effect of core diameter for removing radicular post with ultrasoundJOURNAL OF ORAL REHABILITATION, Issue 6 2004E. Alfredo summary, The removal of radicular posts for endodontic reasons as well as their replacement is a common procedure in dental practice. The use of ultrasound is becoming a standard practice since it reduces the stress to displace the core from the canal minimizing the risks of root fractures, perforations and further wearing of dental structure. Thus, the objective of this study was to evaluate the effect of a reduction in the core diameter when removing radicular posts with ultrasound. Twenty-four teeth were divided in two groups. Group I received posts with the dowel and core of the same diameter (1·7 mm) and group II received posts with the dowel diameter 2 mm larger (3·7 mm) than the core diameter. Zinc phosphate cement was used to cement the posts in all groups. Half of the samples of each group received ultrasonic energy for 8, 2 min for each face. All samples were submitted to traction on an Instron machine (model 4444). Data were analysed statistically with anova and the Tukey test, revealing significant differences (P < 0·05) between groups. The authors concluded that the mean tension necessary to displace the posts from the roots was reduced by 26% when ultrasound was applied. The reduction of the post-diameter reduced the necessary tension to remove them by 24% compared with larger posts. [source] Diffraction losses in ground-based optical interferometersMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2001A.J. Horton We present a numerical analysis of free-space propagation of the beams inside a long-baseline optical/infrared interferometer. Unlike the models of beam propagation used in most previous studies, our analysis incorporates the effects of atmospheric seeing on the wavefronts entering the interferometer. We derive results for the changes in throughput, coherence loss and fringe-detection signal-to-noise ratio arising from diffraction along the propagation path. Our results for conditions of moderate seeing show that although the flux throughput decreases with propagation distance for a given beam diameter, the fringe contrast increases at the same time. In this case it becomes possible for diffraction to increase the signal-to-noise ratio of the fringe measurements. Previous studies have only considered an arrangement where all the apertures in the beam-propagation system have the same diameter. If the light at the end of the propagation path is collected with a fixed size aperture, we find that in many cases the signal-to-noise ratio for fringe detection is maximized when the initial beam diameter is approximately 30 per cent smaller than the final collector diameter. We discuss the implications of our results in the context of future interferometer designs. [source] Planar Droplet Sizing for the Characterization of Droplet Clusters in an Industrial Gun-Type BurnerPARTICLE & PARTICLE SYSTEMS CHARACTERIZATION, Issue 3 2003Laurent Zimmer Abstract An important problem in spray combustion deals with the existence of dense regions of droplets, called clusters. To understand their formation mechanism, the droplet dynamics and fuel concentration profile are investigated by means of planar laser techniques in an industrial gun-type burner. The simultaneous measurement of elastic Mie scattering and Laser Induced Fluorescence (LIF) allows the instantaneous measurement of the Sauter Mean Diameter (SMD), after proper calibration. Using two different CCDs to get the two signals requires a detailed calibration of the CCD response before getting absolute diameters. Pixels are binned 6 by 6 to obtain the final SMD map, this is a compromise between spatial accuracy and noise. Velocity field is measured on both sets of images using standard Particle Image Velocimetry (PIV) algorithms. The comparison of cross-correlation technique with PDA results shows that the velocity measured on the LIF images are close to the velocity based on D30, whereas the Mie scattering results are similar to D20. On Mie scattering images, regions of high interfacial area forming clusters can be detected. A special tracking scheme is used to characterize their dynamics in terms of velocity and diameters by ensuring that the same volume of fluid is tracked. It is shown that the clusters have a velocity similar to the velocity of droplets with the same diameter as the mean SMD of the cluster. It is also shown that an increase of pressure tends to trigger the appearance of such a group of droplets, due to a smaller diameter of the droplets caused by the increase of pressure discharge. Uncertainties for the different techniques used are discussed. [source] The ,false' non-recurrent inferior laryngeal nerveBRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 9 2000M. Rafaelli Background A communication between the middle cervical sympathetic ganglion (MCSG) and the inferior laryngeal nerve (ILN) has been described. The anastomotic branch (sympathetic,inferior laryngeal anastomotic branch; SILAB) is usually thin, but is sometimes larger and has the same diameter as the ILN. The purpose of this study was to evaluate prospectively the frequency of this condition and its implications during neck exploration. Methods From November 1998 to October 1999, 791 neck explorations were performed: 677 for thyroid, 99 for parathyroid and 15 for concomitant lesions. Some 1253 ILNs were dissected: 656 (52·3 per cent) on the right and 597 (47·7 per cent) on the left side. Results The ILN was identified in all cases. On the right side a non-recurrent ILN (NRILN) was found in three patients (0·5 per cent) and a large SILAB in ten (1·5 per cent). No anomalous branch was found on the left side. The SILAB originated from the superior cervical sympathetic ganglion (SCSG) in two patients and directly from the sympathetic chain (SC) above the MCSG in eight. No branch originating from the MCSG was found. The SILAB connected with the ILN less than 2 cm from the cricoid in all patients. Conclusion The SILAB may originate not only from the MCSG but also from the SCSG and directly from the SC. When the SILAB is as large as the ILN, it could be mistaken for a NRILN. Before concluding that the anomalous branch is a NRILN, one should check if it originates from the vagus or from the cervical sympathetic system. Awareness of this anatomical condition during neck exploration may help the surgeon to avoid injuries of an ILN running in the usual pathway. © 2000 British Journal of Surgery Society Ltd [source] A Comparison of Flow Dynamics and Flow Structure in a Riser and a DownerCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 4 2007B. Wu Abstract Flow development and flow dynamics were systematically investigated using local solids concentration measurements in a pair consisting of a downer (0.1,m I.D., 9.3,m high) and a riser of the same diameter (0.1,m I.D., 15.1,m high). Both statistical and chaos analysis were employed. Values for the Kolmogorov entropy (K), correlation dimension (D), and Hurst exponent (H) were estimated from time series of solids concentration measurements. Axial distributions of chaos parameters were more complex in the downer than those in the riser, especially in the entrance section. Flow in the downer was more uniform with a flatter core in all the radial profiles of chaos parameters. The radial profiles of K varied significantly with increasing axial levels due to different clustering behavior in the wall region of the downer. In both the riser and the downer, anti-persistent flow in the core region and persistent flow behavior near the wall were identified from the profiles of H. Different flow behavior in the region close to the wall in the downer and riser was characterized from the combination of the three chaos parameters. Relationships between chaos parameters and local time-averaged solids holdup in the core and wall regions of the developed sections in both the downer and riser were also analyzed. [source] Zero dimensional exciton-polaritonsPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 10 2006A. Baas The cover picture from the article [1] shows, in the left parts of the three diagrams, the measured photoluminescence intensity as a function of energy and emission angle for a 3 ,m (left diagram), 9 ,m (middle diagram) and 19 ,m-diameter quasi-circular mesa (right diagram). The white lines are the energy dispersions of 2D polariton modes. For clarity, intensities above 1485 meV have been multiplied by a constant factor, as indicated. The right parts of the diagrams contain intensity plots of the simulated polariton spectral density for cylindrical mesas of the same diameters, yielding very good quantitative agreement of the 0D polariton states in the circular mesas. This confirms the coexistence of 0D and 2D microcavity polaritons in these semiconductor structures. This paper is an invited presentation from the 8th International Workshop on Nonlinear Optics and Excitation Kinetics. Further articles from NOEKS 8 are published in phys. stat. sol. (c) 3, No. 7 (2006). [source] Ab initio modeling of small diameter silicon nanowiresPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 2 2006Murat Durandurdu Abstract Using ab initio calculations, we predict stable small diameter silicon nanowires. The wires are constructed from the expended phases of silicon, clathrate Si(34) and Si(46) structures, and found to be energetically more favorable than the diamond type nanowires at the same diameters. Furthermore, the wires are semiconducting with band gap energy of 0.22 eV and 0.34 eV. Chemical passivation of the wires with hydrogen induces a broadening of band gap energy due to the quantum size effect and increases the hardness of the wires. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | |||||||||||||