84,693 research outputs found

    Fabrication and experimental evaluation of common domes having waffle-like stiffening. part i- program development

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    Determination of minimum weight shape and stiffening configuration for doubly curved shells subjected to external buckling pressure

    High-Precision Thermodynamics and Hagedorn Density of States

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    We compute the entropy density of the confined phase of QCD without quarks on the lattice to very high accuracy. The results are compared to the entropy density of free glueballs, where we include all the known glueball states below the two-particle threshold. We find that an excellent, parameter-free description of the entropy density between 0.7Tc and Tc is obtained by extending the spectrum with the exponential spectrum of the closed bosonic string.Comment: 4 pages, 3 figure

    An Uqp(u2)U_{qp}(u_2) Rotor Model for Rotational Bands of Superdeformed Nuclei

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    A nonrigid rotor model is developed from the two-parameter quantum algebra Uqp(u2)U_{qp}({\rm u}_2). [This model presents the Uqp(u2)U_{qp}({\rm u}_2) symmetry and shall be referred to as the qp-rotor model.] A rotational energy formula as well as a qp-deformation of E2 reduced transition probabilities are derived. The qp-rotor model is applied (through fitting procedures) to twenty rotational bands of superdeformed nuclei in the A130A \sim 130, 150 and 190 mass regions. Systematic comparisons between the qp-rotor model and the q-rotor model of Raychev, Roussev and Smirnov, on one hand, and a basic three-parameter model, on the other hand, are performed on energy spectra, on dynamical moments of inertia and on B(E2) values. The physical signification of the deformation parameters q and p is discussed.Comment: 24 pages, Latex File, to appear in IJMP

    On-line diagnosis of unrestricted faults

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    A formal model for the study of on-line diagnosis is introduced and used to investigate the diagnosis of unrestricted faults. A fault of a system S is considered to be a transformation of S into another system S' at some time tau. The resulting faulty system is taken to be the system which looks like S up to time tau, and like S' thereafter. Notions of fault tolerance error are defined in terms of the resulting system being able to mimic some desired behavior as specified by a system similar to S. A notion of on-line diagnosis is formulated which involves an external detector and a maximum time delay within which every error caused by a fault in a prescribed set must be detected. It is shown that if a system is on-line diagnosable for the unrestricted set of faults then the detector is at least as complex, in terms of state set size, as the specification. The use of inverse systems for the diagnosis of unrestricted faults is considered. A partial characterization of those inverses which can be used for unrestricted fault diagnosis is obtained

    Compliance with child support orders in divorce cases

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    This paper examines compliance with child support orders by divorced fathers in Wisconsin. Compliance increases as the income of the father increases, although it falls in the highest income category. The "burden" of awards does not affect compliance unless more than 30 percent of income is owed. More stringent enforcement systems increase compliance. We find that most divorced fathers who are not complying with their orders do not have very low incomes, in contrast to noncomplying fathers in nonmarital cases. This suggests that the best policies to increase compliance among divorced fathers may differ from those for nonmarital fathers.

    Drag reduction obtained by rounding vertical corners on a box-shaped ground vehicle

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    A box-shaped ground vehicle was used to simulate the aerodynamic drag of delivery vans, trucks, and motor homes. A coast-down method was used to define the drag of this vehicle in a configuration with all square corners and a modified configuration with the four vertical corners rounded. The tests ranged in velocity from 30 miles per hour to 65 miles per hour, and Reynolds numbers ranged from 4.4 x 1,000,000 to 1.0 x 10 to the 7th power based on vehicle length. The modified configuration showed a reduction in aerodynamic drag of about 40 percent as compared to the square cornered configuration

    On qpqp-Deformations in Statistical Mechanics of Bosons in D Dimensions

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    The Bose distribution for a gas of nonrelativistic free bosons is derived in the framework of qpqp-deformed second quantization. Some thermodynamical functions for such a system in D dimensions are derived. Bose-Einstein condensation is discussed in terms of the parameters q and p as well as a parameter ν0\nu_0' which characterizes the representation space of the oscillator algebra.Comment: 15 pages, Latex File, to be published in Symmetry and Structural Properties of Condensed Matter, Eds. T. Lulek, B. Lulek and W. Florek (World Scientific, Singapore, 1997

    Patterns of Child Support Compliance in Wisconsin

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    This paper examines five-year compliance patterns among Wisconsin child support cases that came to court in 1986–88. We find only limited support for the common assumption that compliance with child support orders declines over time: the average percent paid is about .65 during each of the first five years. The most predominant trend is an increasing polarization into groups of nonpayers and full payers. Although we find considerable stability from year to year among nonpayers and full payers, there is considerable change over the course of five years. Compliance during the first year provides some indication of long-term compliance, but about half of fathers change their compliance rate over the period. We find important differences between divorced and nonmarital fathers, differences that are more pronounced than are apparent from a single year of data. Policy implications are discussed and further research is suggested.

    Past and Ongoing Tsetse and Animal Trypanosomiasis Control Operations in Five African Countries: A Systematic Review

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    Background Control operations targeting Animal African Trypanosomiasis and its primary vector, the tsetse, were covering approximately 128,000 km2 of Africa in 2001, which is a mere 1.3% of the tsetse infested area. Although extensive trypanosomiasis and tsetse (T&T) control operations have been running since the beginning of the 20th century, Animal African Trypanosomiasis is still a major constraint of livestock production in sub-Saharan Africa. Methodology/Principal Findings We performed a systematic review of the existing literature describing T&T control programmes conducted in a selection of five African countries, namely Burkina Faso, Cameroon, Ethiopia, Uganda and Zambia, between 1980 and 2015. Sixty-eight documents were eventually selected from those identified by the database search. This was supplemented with information gathered through semi-structured interviews conducted with twelve key informants recruited in the study countries and selected based on their experience and knowledge of T&T control. The combined information from these two sources was used to describe the inputs, processes and outcomes from 23 major T&T control programmes implemented in the study countries. Although there were some data gaps, involvement of the target communities and sustainability of the control activities were identified as the two main issues faced by these programmes. Further, there was a lack of evaluation of these control programmes, as well as a lack of a standardised methodology to conduct such evaluations. Conclusions/Significance Past experiences demonstrated that coordinated and sustained control activities require careful planning, and evidence of successes, failures and setbacks from past control programmes represent a mine of information. As there is a lack of evaluation of these programmes, these data have not been fully exploited for the design, analyses and justification of future control programmes
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