A Format for Storing and Managing Multiple Level of Detail Terrain for Simulated Environments

This study investigated a method of storing, managing and rendering terrain data, while addressing conflicting goals of. rendering speed, display detail and memory usage. A data structure is presented to store terrain data, with an object oriented system to manage the data stored in the structure. The structure stores terrain data in a compact form which is converted into rendering structures in real time. The structure uses levels of detail to maintain display detail. The structure is compared against an existing format for storing terrain data, MultiGen Flight. The system managing the structure is shown to decrease memory usage and increase frame rate, while maintaining display detail. The structure offers features not attainable from Flight format, including: interpolating vertices to prevent cracking, defining levels of detail by altitude or speed, and betweening. The structure allows storing and rendering larger databases than previously manageable with Flight format

Alternative experimental evidence for chiral restoration in excited baryons

Given existing empirical spectral patterns of excited hadrons it has been suggested that chiral symmetry is approximately restored in excited hadrons at zero temperature/density (effective symmetry restoration). If correct, this implies that mass generation mechanisms and physics in excited hadrons is very different as compared to the lowest states. One needs an alternative and independent experimental information to confirm this conjecture. Using very general chiral symmetry arguments it is shown that strict chiral restoration in a given excited nucleon forbids its decay into the N \pi channel. Hence those excited nucleons which are assumed from the spectroscopic patterns to be in approximate chiral multiplets must only "weakly" decay into the N \pi channel, (f_{N^*N\pi}/f_{NN\pi})^2 << 1. However, those baryons which have no chiral partner must decay strongly with a decay constant comparable with f_{NN\pi}. Decay constants can be extracted from the existing decay widths and branching ratios. It turnes out that for all those well established excited nucleons which can be classified into chiral doublets N_+(1440) - N_-(1535), N_+(1710) - N_-(1650), N_+(1720) - N_-(1700), N_+(1680) - N_-(1675), N_+(2220) - N_-(2250), N_+(?) - N_-(2190), N_+(?) - N_-(2600), the ratio is (f_{N^*N\pi}/f_{NN\pi})^2 ~ 0.1 or much smaller for the high-spin states. In contrast, the only well established excited nucleon for which the chiral partner cannot be identified from the spectroscopic data, N(1520), has a decay constant into the N\pi channel that is comparable with f_{NN\pi}. This gives an independent experimental verification of the chiral symmetry restoration scenario.Comment: 4 pp. A new footnote with an alternative proof of impossibility of parity doublet decay into pi + N is added. To appear in Phys. Rev. Let

The use of computer-generated color graphic images for transient thermal analysis

Color computer graphics techniques were investigated as a means of rapidly scanning and interpreting large sets of transient heating data. The data presented were generated to support the conceptual design of a heat-sink thermal protection system (TPS) for a hypersonic research airplane. Color-coded vector and raster displays of the numerical geometry used in the heating calculations were employed to analyze skin thicknesses and surface temperatures of the heat-sink TPS under a variety of trajectory flight profiles. Both vector and raster displays proved to be effective means for rapidly identifying heat-sink mass concentrations, regions of high heating, and potentially adverse thermal gradients. The color-coded (raster) surface displays are a very efficient means for displaying surface-temperature and heating histories, and thereby the more stringent design requirements can quickly be identified. The related hardware and software developments required to implement both the vector and the raster displays for this application are also discussed

Alloys similar to duralumin made in other countries than Germany

Attempts by other countries to develop patents for alloys similar to duralumin are presented. Duralumin is aluminum alloyed with 3.5-4.5% copper, 0.5% magnesium, and 0.25-1% of manganese

Pressure measurements in a low-density nozzle plume for code verification

Measurements of Pitot pressure were made in the exit plane and plume of a low-density, nitrogen nozzle flow. Two numerical computer codes were used to analyze the flow, including one based on continuum theory using the explicit MacCormack method, and the other on kinetic theory using the method of direct-simulation Monte Carlo (DSMC). The continuum analysis was carried to the nozzle exit plane and the results were compared to the measurements. The DSMC analysis was extended into the plume of the nozzle flow and the results were compared with measurements at the exit plane and axial stations 12, 24 and 36 mm into the near-field plume. Two experimental apparatus were used that differed in design and gave slightly different profiles of pressure measurements. The DSMC method compared well with the measurements from each apparatus at all axial stations and provided a more accurate prediction of the flow than the continuum method, verifying the validity of DSMC for such calculations

Beyond Foreign Policy? EU Sanctions at the Intersection of Development, Trade, and CFSP

In the wake of unsettling conflicts and democratic backsliding, states and organisations increasingly respond with sanctions. The European Union (EU) is one of them: Brussels makes use of the entire toolbox in its foreign policy, and its sanctions appear in different forms - diplomatic measures, travel bans, financial bans, or various forms of economic restrictions. Yet, there is little debate between different strands in the literature on EU sanctions, in particular concerning measures under the Common Foreign and Security Policy and those pertaining to the development and trade policy fields. Our thematic issue addresses this research gap by assembling a collection of articles investigating the design, impact, and implementation of EU sanctions used in different realms of its external affairs. Expanding the definition of EU sanctions to measures produced under different guises in the development, trade, and foreign policy fields, the collection overcomes the compartmentalised approach characterising EU scholarship

Measurement and analysis of a small nozzle plume in vacuum

Pitot pressures and flow angles are measured in the plume of a nozzle flowing nitrogen and exhausting to a vacuum. Total pressures are measured with Pitot tubes sized for specific regions of the plume and flow angles measured with a conical probe. The measurement area for total pressure extends 480 mm (16 exit diameters) downstream of the nozzle exit plane and radially to 60 mm (1.9 exit diameters) off the plume axis. The measurement area for flow angle extends to 160 mm (5 exit diameters) downstream and radially to 60 mm. The measurements are compared to results from a numerical simulation of the flow that is based on kinetic theory and uses the direct-simulation Monte Carlo (DSMC) method. Comparisons of computed results from the DSMC method with measurements of flow angle display good agreement in the far-field of the plume and improve with increasing distance from the exit plane. Pitot pressures computed from the DSMC method are in reasonably good agreement with experimental results over the entire measurement area

Occupation-Based Intervention Tool for Postoperative Upper Extremity Nerve Laceration

Purpose The purpose of the product was to create an accessible resource for occupational therapists to implement occupation-based interventions effectively. Methods The results of a thorough literature review on the shared topic of interest supported the therapeutic value of occupation through education and home programming. The literature was used to justify the gap that exists in the need for the implementation of occupation-based interventions in hand therapy. The results from the literature review was synthesized into a detailed narrative that guided the formation of a patient education tool. The product was designed using concepts from the biomechanical frame of reference, Model of Human Occupation, and the Adult Learning Theory. These three theories work together to address the physical aspects of the human body, the internal factors of a person, and how to best relay information to an individual. Aspects from each of these theories were combined in order to increase the usability and effectiveness of occupation-based interventions in hand therapy settings. Results The literature and theoretical perspectives resulted in the formation of a collaborative patient education product. The product is meant to be used collaboratively between an occupational therapist and an individual with an upper extremity nerve laceration in an outpatient setting. The topics covered in this tool include neuroanatomy and neuroscience, common procedures, rehabilitation process, occupation-based intervention rationale, coping strategies, and assessment and goal formation. The product includes a separate therapist manual that provides a brief summary of the research studies found that support the formation of the product. Conclusions It is anticipated that the patient education tool will be an efficient and effective solution to the perceived barriers that occupational therapists in hand therapy have to implementing occupation-based interventions. In addition to assisting therapists, it is the intention that this tool will improve the adherence to therapy routines, patient satisfaction, and patient outcomes

Ariel - Volume 3 Number 5

Editors Richard J. Bonanno Robin A. Edwards Associate Editors Steven Ager Tom Williams Lay-out Editor Eugenia Miller Contributing Editors Paul Bialas Robert Breckenridge Lynne Porter David Jacoby Terry Burt Mark Pearlman Michael Leo Mike LeWitt Editors Emeritus Delvyn C. Case., Jr. Paul M. Fernhof

Multi-Magnon Scattering in the Ferromagnetic XXX-Model with Inhomogeneities

We determine the transition amplitude for multi-magnon scattering induced through an inhomogeneous distribution of the coupling constant in the ferromagnetic XXX-model. The two and three particle amplitudes are explicitely calculated at small momenta. This suggests a rather plausible conjecture also for a formula of the general n-particle amplitude.Comment: 21 pages, latex, no figure