21,434 research outputs found
Combined State and Parameter Estimation for a Static Model of the Maypole (Hoop-Column) Antenna Suface
Parameter and state estimation techniques are discussed for an elliptic system arising in a developmental model for the antenna surface of the Maypole Hoop/Column antenna. A computational algorithm based on spline approximations for the state and elastic parameters is given and numerical results obtained using this algorithm are summarized
Completion Report: Arkansas State Pesticides in Ground Water Monitoring Project Phase V: Vulnerable areas in Jackson, Monroe, Lawrence and Lonoke Counties
In 1996, sixty-seven water samples were drawn from 65 wells, including 62 new wells and 3 wells sampled previously . One Woodruff County well and two Pulaski County wells were resampled. Thirty-two samples were drawn from 30 wells in Monroe County (well #1 was sampled 3 times during this phase) . Ten wells in Jackson County, 12 wells in Lawrence County and 10 wells in Lonoke were also tested (Figures 1-5) . With the completion of Phase V, the number of wells tested has risen to 231 with a total of 258 samples analyzed . Initially, the wells were tested for 13 pesticides and ni~rate. Two more pesticides, aldicarb and carbofuran were added to the analyte list during Phase V. The analyte list is shown in Table 3 . All results from all the wells are listed in Appendix A. Quality control information for these data follow the results. The Phase V Quality Assurance Report is included in this document as Part II
Two-Band-Type Superconducting Instability in MgB2
Using the tight-binding method for the -bands in MgB, the Hubbard
on-site Coulomb interaction on two inequivalent boron -orbitals is
transformed into expressions in terms of -band operators. For scattering
processes relevant to the problemin which a wave vector {\bf q} is parallel to
, it is found to take a relatively simple form consisting of
intra-band Coulomb scattering, interband pair scattering etc. with large
constant coupling constants. This allows to get a simple expression for the
amplitude of interband pair scattering between two -bands, which diverges
if the interband polarization function in it becomes large enough.The latter
was approximately evaluated and found to be largely enhanced in the band
structure in MgB. These results lead to a divergent interband pair
scattering, meaning two-band-type superconducting instability with enhanced
. Adding a subsidiary BCS attractive interaction in each band into
consideration, a semi-quantitative gap equation is given, and and isotope
exponent are derived. The present instability is asserted to be the
origin of high in MgB.Comment: 4 pages, to be published in J. Phys. Soc. Jpn. vol. 70, No.
Role of Boron p-Electrons and Holes in Superconducting MgB2, and other Diborides: A Fully-Relaxed, Full-Potential Electronic Structure Study
We present the results of fully-relaxed, full-potential electronic structure
calculations for the new superconductor MgB2, and BeB2, NaB2, and AlB2, using
density-functional-based methods. Our results described in terms of (i) density
of states (DOS), (ii) band-structure, and (iii) the DOS and the charge density
around the Fermi energy EF, clearly show the importance of B p-band for
superconductivity. In particular, we show that around EF, the charge density in
MgB2, BeB2 and NaB2 is planar and is associated with the B plane. For BeB2 and
NaB2, our results indicate qualitative similarities but significant
quantitative differences in their electronic structure due to different lattice
constants a and c.Comment: 4 pages, 4 figures, Submitted to Phys Rev. Lett. on March 6, 2001;
resubmission on April 2
Memetic Multilevel Hypergraph Partitioning
Hypergraph partitioning has a wide range of important applications such as
VLSI design or scientific computing. With focus on solution quality, we develop
the first multilevel memetic algorithm to tackle the problem. Key components of
our contribution are new effective multilevel recombination and mutation
operations that provide a large amount of diversity. We perform a wide range of
experiments on a benchmark set containing instances from application areas such
VLSI, SAT solving, social networks, and scientific computing. Compared to the
state-of-the-art hypergraph partitioning tools hMetis, PaToH, and KaHyPar, our
new algorithm computes the best result on almost all instances
The development of a novel steerable bougie to assist in airway management
Background: This paper describes the development of a new airway device that will improve the speed and safety of endotracheal intubation in anaesthesia and critical care. Case of need, design specification and fabrication of the steerable bougie mechanism is discussed. Aims: Identify the need for a novel steerable bougie whilst considering technology readiness levels associated with medical device design. Analyse and produce suitable mechanisms utilising smart materials to increase device functionality aiding successful patient intubation procedures. Methods: This work describes the total design activity that contributes to the successful development of medical devices, from case of need, to smart material actuation mechanisms. Research focuses on identifying a suitable control mechanism to allow a steerable tip to be integrated into a bougie with a control device attached to the laryngoscope. Results: Data collected from a user group survey supported the development of a novel bougie, with better shape retention, variable rigidity within the tip, and an integrated steerable function. Analysis of several mechanisms, artificial muscles, and smart materials identified a cost-effective steerable mechanism that can be incorporated into a bougie. Conclusion: Users have defined a need for an improved bougie. Controlling smart materials and mechanisms, within the predefined dimensions, identified strengths and weaknesses associated with steerable functions. The performance of the selected mechanism for incorporation requires a high level of control to accurately steer a device within the human airway
Particle Ratios, Equilibration, and the QCD Phase Boundary
We discuss the status of thermal model descriptions of particle ratios in
central nucleus-nucleus collisions at ultra-relativistic energy. An alternative
to the
``Cleymans-Redlich'' interpretation of the freeze-out trajectory is given in
terms of the total baryon density. Emphasis is placed on the relation between
the chemical equilibration parameters and the QCD phase boundary. Furthermore,
we trace the essential difference between thermal model analyses of data from
collisions between elementary particles and from heavy ion collisions as due to
a transition from local strangeness conservation to percolation of strangeness
over large volumes, as occurs naturally in a deconfined medium.
We also discuss predictions of the thermal model for composite particle
production.Comment: Contribution to SQM2001 Conference, submitted to J. Phys.
Recommended from our members
Utilising object tracking for the performance analysis of difficult airway equipment - a Shape Retention Testing System (SRTS)
Failure to secure the airway on induction of anaesthesia can result in death and disability. Current equipment does not always provide an optimum solution. Most anaesthetists consider bougies essential equipment for safe anaesthesia. Evaluative systems providing accurate objective data assessing bougie introducer performance data do not exist. The Shape Retention Testing System (SRTS) utilises the Intel® RealSenseTM SR300 camera to create an accurate and repeatable testing environment. SRTS collected data will allow anaesthetists to compare device performance that will inform purchase and usage decisions of bougies, ensuring optimum benefit for safe practice
Observations of TeV gamma rays from Markarian 501 at large zenith angles
TeV gamma rays from the blazar Markarian 501 have been detected with the
University of Durham Mark 6 atmospheric Cerenkov telescope using the imaging
technique at large zenith angles. Observations were made at zenith angles in
the range 70 - 73 deg during 1997 July and August when Markarian 501 was
undergoing a prolonged and strong flare.Comment: 7 pages, 2 figures, accepted for publication in J. Phys. G.: Nucl.
Part. Phy
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