916 research outputs found
Cementless RM Pressfit® Cup. A clinical and radiological study of 91 cases with at least four years follow-up
AbstractCementless metal-back acetabular cups have good long-term results, but some problems have appeared due to the shell's stiffness, modularity and required bearing surfaces. The RM Pressfit® Cup is a single-piece polyethylene cementless acetabular cup that is covered by a thin layer of titanium. This allows for bone integration without limitations related to the stiffness of a metal-back shell. There is very little published information about this new, innovative implant design. The purpose of this study was to evaluate the clinical and radiological results from a continuous series of 91 cups (85 patients) with a follow-up of at least 4years. No patients were lost to follow-up. The Harris Hip Score (HHS) was used to assess the clinical outcome. To assess the radiological outcomes, digital X-rays were used to evaluate the cup position and integration; wear was measured using Livermore's technique. The clinical results were excellent: the mean HHS was 94 and 82% of cases had good or excellent scores. Three of the cups had to be revised because of dislocation brought on by incorrect positioning. X-rays revealed that three implants had shifted during the first 6weeks, but had stabilized afterwards. Bone integration on X-rays was satisfactory in all cases with no signs of osteolysis. The configuration of the bone trabeculae showed that loads between the implant and peri-acetabular cancellous bone were evenly distributed. The wear of the polyethylene cup-ceramic head bearing was 0.07mm/year. The results of this series are consistent with recent published studies with the RM Pressfit® Cup.Level of evidenceIV
Towards Integration of CAx Systems and a Multiple-View Product Modeller in Mechanical Design
This paper deals with the development of an integration framework and its implementation for the connexion of CAx systems and multiple-view product modelling. The integration framework is presented regarding its conceptual level and the implementation level is described currently with the connexion of a functional modeller, a multiple-view product modeller, an optimisation module and a CAD system. The integration between the multiple-view product modeller and CATIA V5 based on the STEP standard is described in detail. Finally, the presented works are discussed and future research developments are suggested.
Piezoelectric and optical setup to measure an electrical field: Application to the longitudinal near-field generated by a tapered coax
We propose a new setup to measure an electrical field in one direction. This
setup is made of a piezoelectric sintered lead zinconate titanate film and an
optical interferometric probe. We used this setup to investigate how the shape
of the extremity of a coaxial cable influences the longitudinal electrical
near-field generated by it. For this application, we designed our setup to have
a spatial resolution of 100 um in the direction of the electrical field.
Simulations and experiments are presented
Impact of LiBSO glass additive on the structure and electrical properties of the LATP-based ceramics
The existing solid electrolytes for lithium ion batteries suffer from low
total ionic conductivity, which restricts its usefulness for the lithium-ion
battery technology. Among them, the NASICON-based materials, such as
Li1.3Al0.3Ti1.7(PO4)3 (LATP) exhibit low total ionic conductivity due to highly
resistant grain boundary phase. One of the possible approaches to efficiently
enhance their total ionic conductivity is the formation of a composite
material. Herein, the Li2.9B0.9S0.1O3.1 glass, called LBSO hereafter, was
chosen as an additive material to improve the ionic properties of the ceramic
Li1.3Al0.3Ti1.7(PO4)3 base material. The properties of this
Li1.3Al0.3Ti1.7(PO4)3-xLi2.9B0.9S0.1O3.1 (0 < x < 0.3) system have been studied
by means of high temperature X-ray diffractometry (HTXRD), 7Li, 11B, 27Al and
31P magic angle spinning nuclear magnetic resonance spectroscopy (MAS NMR),
thermogravimetry (TG), scanning electron microscopy (SEM), impedance
spectroscopy (IS) and density methods. We show here that the introduction of
the foreign LBSO phase enhances their electric properties. This study reveals
several interesting correlations between the apparent density, the
microstructure, the composition, the sintering temperature and the ionic
conductivity. Moreover, the electrical properties of the composites will be
discussed in the terms of the brick-layer model (BLM). The highest value of
{\sigma}tot = 1.5 x 10-4 Scm-1 has been obtained for LATP-0.1LBSO material
sintered at 800{\deg}C
Satellites of the largest Kuiper Belt objects
We have searched the four brightest objects in the Kuiper Belt for the presence of satellites using the newly commissioned Keck Observatory Laser Guide Star Adaptive Optics system. Satellites are seen around three of the four objects: Pluto (whose satellite Charon is well-known and whose recently discovered smaller satellites are too faint to be detected), 2003 EL61 (where a second satellite is seen in addition to the previously known satellite), and 2003 UB313 (where a satellite is seen for the first time). The object 2005 FY9, the brightest Kuiper Belt object (KBO) after Pluto, does not have a satellite detectable within 0".4 with a brightness of more than 1% of the primary. The presence of satellites around three of the four brightest KBOs is inconsistent with the fraction of satellites in the Kuiper Belt at large at the 99.2% confidence level, suggesting a different formation mechanism for these largest KBO satellites. The two satellites of 2003 EL61, and the one satellite of 2003 UB313, with fractional brightnesses of 5% and 1.5%, and 2%, of their primaries, respectively, are significantly fainter relative to their primaries than other known KBO satellites, again pointing to possible differences in their origin
Electromagnetic Hydrophone with Tomographic System for Absolute Velocity Field Mapping
The velocity and pressure of an ultrasonic wave can be measured by an
electromagnetic hydrophone made of a thin wire and a magnet. The ultrasonic
wave vibrates the wire inside a magnetic field, inducing an electrical current.
Previous articles reported poor spatial resolution of comparable hydrophones
along the axis of the wire. In this study, submillimetric spatial resolution
has been achieved by using a tomographic method. Moreover, a physical model is
presented for obtaining absolute measurements. A pressure differential of 8%
has been found between piezoelectric and electromagnetic hydrophone
measurements. These characteristics show this technique as an alternative to
standard hydrophones
Properties of LiMnBO3 glasses and nanostructured glass-ceramics
Polycrystalline LiMnBO3 is a promising cathode material for Li-ion batteries.
In this work, we investigated the thermal, structural and electrical properties
of glassy and nanocrystallized materials having the same chemical composition.
The original glass was obtained via a standard meltquenching method. SEM and
7Li solid-state NMR indicate that it contains a mixture of two distinct glassy
phases. The results suggest that the electrical conductivity of the glass is
dominated by the ionic one. The dc conductivity of initial glass was estimated
to be in the order of 10-18 S.cm-1 at room temperature. The thermal
nanocrystallization of the glass produces a nanostructured glass-ceramics
containing MnBO3 and LiMnBO3 phases. The electric conductivity of this
glass-ceramics is increased by 6 orders of magnitude, compared to the starting
material at room temperature. Compared to other manganese and borate containing
glasses reported in the literature, the conductivity of the nanostructured
glass ceramics is higher than that of the previously reported glassy materials.
Such improved conductivity stems from the facilitated electronic transport
along the grain boundaries
Sonically-enhanced widgets: comments on Brewster and Clarke, ICAD 1997
This paper presents a review of the research surrounding the paper “The Design and Evaluation of a Sonically Enhanced Tool Palette” by Brewster and Clarke from ICAD 1997. A historical perspective is given followed by a discussion of how this work has fed into current developments in the area
- …