538 research outputs found
An Enhanced Tire Model for Dynamic Simulation based on Geometrically Exact Shells
In the present work, a tire model is derived based on geometrically exact shells. The discretization is done with the help of isoparametric quadrilateral finite elements. The interpolation is performed with bilinear Lagrangian polynomials for the midsurface as well as for the director field. As time stepping method for the resulting differential algebraic equation a backward differentiation formula is chosen. A multilayer material model for geometrically exact shells is introduced, to describe the anisotropic behavior of the tire material. To handle the interaction with a rigid road surface, a unilateral frictional contact formulation is introduced. Therein a special surface to surface contact element is developed, which rebuilds the shape of the tire
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1995 Annual report on waste generation and waste mainization progress as required by DOE order 5400.1, Hanford site
While waste generation numbers are important, the true measure of success is waste minimized. Many Waste Minimization/Pollution Prevention (WMin/P2) successes at the Hanford Site occur every day without formal recognition as pollution prevention, as they have become part of a culture of best management practices. As an example, the success of the excess and reuse program, both informal and formal, documents the Wmin/P2 culture that exists in the pollution prevention representatives and employees at the facilities
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The U.S. Department of Energy pollution prevention program: Applications for small business
This report shows the benefits small businesses can realize by instituting cost-effective pollution prevention improvements. It is a series of pollution prevention assessments that were conducted at small businesses in Richland, Washington. It describes a technology transfer test of US Department of Energy (USDOE) pollution prevention methods to small businesses through eleven pollution prevention assessments conducted at small businesses in the city of Richland. The assessment method tested was first developed at the USDOE Hanford Site, located in Richland, Washington. Two pilot studies were initially conducted to determine the usefulness of the assessment method for small businesses. Then, four additional pollution prevention assessments were conducted using a refined process. In order to determine the assessment method`s usefulness by different practitioners, a number of the assessments contained in this report were conducted by the undergraduate and graduate students at Washington State University at Tri-Cities as part of their class projects. These students were trained in the pollution prevention assessment process by the author of this report and conducted five small business assessments using the same methods and materials as in the remainder of the study
An energy-momentum consistent time integration scheme based on a mixed framework for non-linear electro-elastodynamics
The objective of the present work is the introduction of new mixed variational principles for EM time integrators in electromechanics, hence bridging the gap between the previous work presented by the authors in References [11] and [1], opening up the possibility to a variety of new Finite Element implementations
Fixed-angle plates in patella fractures - a pilot cadaver study
<p>Abstract</p> <p>Objective</p> <p>Modified anterior tension wiring with K-wires and cannulated lag screws with anterior tension wiring are currently the fixation of choice for patellar fractures. Failure of fixation, migration of the wires, postoperative pain and resulting revision surgery, however, are not uncommon. After preliminary biomechanical testing of a new fixed-angle plate system especially designed for fixation of patella fractures the aim of this study was to evaluate the surgical and anatomical feasibility of implanting such a plate-device at the human patella.</p> <p>Methods</p> <p>In six fresh unfixed female cadavers without history of previous fractures around the knee (average age 88.8 years) a bilateral fixed-angle plate fixation of the patella was carried out after previous placement of a transverse central osteotomy. Operative time, intra-operative problems, degree of retropatellar arthritis (following Outerbridge), quality of reduction and existence of any intraarticular screw placement have been raised. In addition, lateral and anteroposterior radiographs of all specimens were made.</p> <p>Results</p> <p>Due to the high average age of 88.8 years no patella showed an unimpaired retropatellar articular surface and all were severely osteoporotic, which made a secure fixation of the reduction forceps during surgery difficult. The operation time averaged 49 minutes (range: 36-65). Although in postoperative X-rays the fracture gap between the fragments was still visible, the analysis of the retropatellar surface showed no residual articular step or dehiscence > 0.5 mm. Also in a total of 24 inserted screws not one intraarticular malposition was found. No intraoperative complications were noticed.</p> <p>Conclusions</p> <p>Osteosynthesis of a medial third patella fracture with a bilateral fixed-angle plate-device is surgically and anatomically feasible without difficulties. Further studies have to depict whether the bilateral fixed-angle plate-osteosynthesis of the patella displays advantages over the established operative procedures.</p
Carrier-envelope phase control over pathway interference in strong-field dissociation of H
The dissociation of an H molecular-ion beam by linearly polarized,
carrier-envelope-phase-tagged 5 fs pulses at 4W/cm with a
central wavelength of 730 nm was studied using a coincidence 3D momentum
imaging technique. Carrier-envelope-phase-dependent asymmetries in the emission
direction of H fragments relative to the laser polarization were observed.
These asymmetries are caused by interference of odd and even photon number
pathways, where net-zero photon and 1-photon interference predominantly
contributes at H+H kinetic energy releases of 0.2 -- 0.45 eV, and
net-2-photon and 1-photon interference contributes at 1.65 -- 1.9 eV. These
measurements of the benchmark H molecule offer the distinct advantage
that they can be quantitatively compared with \textit{ab initio} theory to
confirm our understanding of strong-field coherent control via the
carrier-envelope phase
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