Contents of Volume 17

Table of Contents

Contents of Volume 17     

A note on modifying a two-dimensional trim-loss algorithm to deal with cutting restrictions

Restrictions upon the placement and number of cuts can arise in a two-dimensional trim-loss problem. It is shown how to modify the two or three-stage algorithms of Gilmore and Gomory to deal with such restrictions. Computational experience shows the modified procedures are viable in a practical application although an optimal solution can no longer be guaranteed.     

Computation of the center and diameter of outerplanar graphs

The center of a graph is the set of vertices with minimum eccentricity. An outerplanar graph is a planar segmentation of a polygon. We define a notion of edge eccentricities for the edges of an outerplanar graph. We present an algorithm which efficiently computes these edge eccentricities. Knowledge of the edge eccentricities allows subsequent linear time computation of the center and diameter of outerplanar graphs. The computation of edge eccentricities is shown to require linear time for certain subclasses of outerplanar graphs.     

The Automorphism Group of the Fibonacci Poset: A “Not Too Difficult” Problem of Stanley from 1988

All of the automorphisms of the Fibonacci poset Z(r) are determined (r ). A problem of Richard P. Stanley from 1988 is thereby solved.     

Measurement of the positive muon anomalous magnetic moment to 0.7 ppm

A higher precision measurement of the anomalous g value, a(mu)=(g-2)/2, for the positive muon has been made at the Brookhaven Alternating Gradient Synchrotron, based on data collected in the year 2000. The result a(mu(+))=11 659 204(7)(5)x10(-10) (0.7 ppm) is in good agreement with previous measurements and has an error about one-half that of the combined previous data. The present world average experimental value is a(mu)(expt)=11 659 203(8)x10(-10) (0.7 ppm).     

Coproducts of bounded distributive lattices: cancellation

Let denote the coproduct of the bounded distributive lattices L and M. At the 1981 Banff Conference on Ordered Sets, the following question was posed: What is the largest class L of finite distributive lattices such that, for every non-trivial Boolean lattice B and every implies ? In this note, the problem is solved. Received March 2, 1999; accepted in final form July 10, 2000.     

Extremal graphs having no matching cuts

A graph G = (V, E) is matching immune if there is no matching cut in G. We show that for any matching immune graph G, |E|≥?3(|V|?1)/2?. This bound is tight, as we define operations that construct, from a given vertex, exactly the class of matching immune graphs that attain the bound. © 2011 Wiley Periodicals, Inc. J Graph Theory 69:206‐222, 2012 .     

Emptying and filling a tunnel bronze

The classical orthorhombic layered phase of V₂O₅ has long been regarded as the thermodynamic sink for binary vanadium oxides and has found great practical utility as a result of its open framework and easily accessible redox states. Herein, we exploit a cation-exchange mechanism to synthesize a new stable tunnel-structured polymorph of V₂O₅ (ζ-V₂O₅) and demonstrate the subsequent ability of this framework to accommodate Li and Mg ions. The facile extraction and insertion of cations and stabilization of the novel tunnel framework is facilitated by the nanometer-sized dimensions of the materials, which leads to accommodation of strain without amorphization. The topotactic approach demonstrated here indicates not just novel intercalation chemistry accessible at nanoscale dimensions but also suggests a facile synthetic route to ternary vanadium oxide bronzes (M_xV₂O₅) exhibiting intriguing physical properties that range from electronic phase transitions to charge ordering and superconductivity.     

In-plane shear testing of graphite-woven fabric composites

The losipescu shear test method was used to determine the in-plane shear response of AS4 and Celion carbon fiber/epoxy fabric composite materials. Several weave architectures were studied: AS4 uniweave, AS4 and Celion plain weaves, Celion 5-harness and 8-harness satin weaves. Specimens were tested using traditional strain gage techniques and full-field moiré interferometry. A full-node localized hybrid analysis is introduced to perform efficient reduction of moiré data, producing whole-field strain distributions in the specimen test section. It was found that the fabric yarn size greatly influenced the uniformity of the shear field in the specimen test section. However, consistent shear moduli still can be obtained using the modified losipescu specimen and Wyoming fixture except for fabrics with large fiber yarns.     

Acquisition of detailed laryngeal flow measurements in geometrically realistic models

Characterization of laryngeal flow velocity fields is important to understanding vocal fold vibration and voice production. One common method for acquiring flow field data is particle image velocimetry (PIV). However, because using PIV with models that have curved surfaces is problematic due to optical distortion, experimental investigations of laryngeal airflow are typically performed using models with idealized geometries. In this paper a method for acquiring PIV data using models with realistic geometries is presented. Sample subglottal, intraglottal, and supraglottal PIV data are shown. Capabilities and limitations are discussed, and suggestions for future implementation are provided.