50,470 research outputs found

    Oral health beliefs and behaviors of nurse and nurse practitioner students using the HU-DBI inventory: An opportunity for oral health vicarious learning

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    Background: Oral health access to care issues are resulting in curricular changes to train nursing students as oral health educators and providers. However, little data are available concerning their personal oral health beliefs/behaviors. The study purpose was to gather information from nurse and nurse practitioner students regarding their oral health beliefs and behaviors. Methods: Using the Hiroshima University Dental Behavioural Inventory (HU-DBI), survey data were gathered from nurse and nurse practitioner students as well as dental hygiene students as controls concerning their oral health beliefs and behaviors. Results: Mean HU-DBI scores were higher among nurse practitioner than nursing students, indicating more positive beliefs/behaviors, but both were lower than dental hygiene students. Both nurse and nurse practitioner students reported significantly fewer dental visits and some poorer hygiene practices than controls. Additionally, nursing students were more likely to believe that their teeth were worsening despite brushing. Conclusions: Assessment of personal oral health beliefs/behaviors should occur early in nursing education with mentoring so that optimal modeling can positively impact patients’ oral health. Oral health education opportunities within and among disciplines are discussed

    Design study of a continuously variable roller cone traction CVT for electric vehicles

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    Continuously variable ratio transmissions (CVT) featuring cone and roller traction elements and computerized controls are studied. The CVT meets or exceeds all requirements set forth in the design criteria. Further, a scalability analysis indicates the basic concept is applicable to lower and higher power units, with upward scaling for increased power being more readily accomplished

    Asymptotic integration algorithms for nonhomogeneous, nonlinear, first order, ordinary differential equations

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    New methods for integrating systems of stiff, nonlinear, first order, ordinary differential equations are developed by casting the differential equations into integral form. Nonlinear recursive relations are obtained that allow the solution to a system of equations at time t plus delta t to be obtained in terms of the solution at time t in explicit and implicit forms. Examples of accuracy obtained with the new technique are given by considering systems of nonlinear, first order equations which arise in the study of unified models of viscoplastic behaviors, the spread of the AIDS virus, and predator-prey populations. In general, the new implicit algorithm is unconditionally stable, and has a Jacobian of smaller dimension than that which is acquired by current implicit methods, such as the Euler backward difference algorithm; yet, it gives superior accuracy. The asymptotic explicit and implicit algorithms are suitable for solutions that are of the growing and decaying exponential kinds, respectively, whilst the implicit Euler-Maclaurin algorithm is superior when the solution oscillates, i.e., when there are regions in which both growing and decaying exponential solutions exist

    A viscoplastic model with application to LiF-22 percent CaF2 hypereutectic salt

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    A viscoplastic model for class M (metal-like behavior) materials is presented. One novel feature is its use of internal variables to change the stress exponent of creep (where n is approximately = 5) to that of natural creep (where n = 3), in accordance with experimental observations. Another feature is the introduction of a coupling in the evolution equations of the kinematic and isotropic internal variables, making thermal recovery of the kinematic variable implicit. These features enable the viscoplastic model to reduce to that of steady-state creep in closed form. In addition, the hardening parameters associated with the two internal state variables (one scalar-valued, the other tensor-valued) are considered to be functions of state, instead of being taken as constant-valued. This feature enables each internal variable to represent a much wider spectrum of internal states for the material. The model is applied to a LiF-22 percent CaF2 hypereutectic salt, which is being considered as a thermal energy storage material for space-based solar dynamic power systems

    Steady-state and transient Zener parameters in viscoplasticity: Drag strength versus yield strength

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    A hypothesis is put forth which enables the viscoplastician to formulate a theory of viscoplasticity that reduces, in closed form, to the classical theory of creep. This hypothesis is applied to a variety of drag and yield strength models. Because of two theoretical restrictions that are a consequence of this hypothesis, three different yield strength models and one drag strength model are shown to be theoretically admissible. One of these yield strength models is selected as being the most appropriate representation for isotropic hardening

    Young Citizens of the World Unite! A Case for the Model United Nations in Middle School Classrooms

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    In this manuscript, the authors describe the benefits and theoretical connections the Junior Model United Nations (JMUN) program has with middle school classrooms. The lens used to view the JMUN program is informed by literature on the needs of young adolescents, inquiry learning, and global citizenship. Findings from this literature illuminate nuances in the interaction between inquiry learning through the C3 Framework and active learning participation. Implications for middle school students, in-service teachers, and teacher candidates are discussed

    Stability of the Magnetic Monopole Condensate in three- and four-colour QCD

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    It is argued that the ground state of three- and four-colour QCD contains a monopole condensate, necessary for the dual Meissner effect to be the mechanism of confinement, and support its stability on the grounds that it gives the off-diagonal gluons an effective mass sufficient to remove the unstable ground state mode.Comment: jhep.cls, typos corrected, references added, some content delete

    Life prediction and constitutive models for engine hot section anisotropic materials program

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    This report presents a summary of results from a 7 year program designed to develop generic constitutive and life prediction approaches and models for nickel-based single crystal gas turbine airfoils. The program was composed of a base program and an optional program. The base program addressed the high temperature coated single crystal regime above the airfoil root platform. The optional program investigated the low temperature uncoated single crystal regime below the airfoil root platform including the notched conditions of the airfoil attachment. Both base and option programs involved experimental and analytical efforts. Results from uniaxial constitutive and fatigue life experiments of coated and uncoated PWA 1480 single crystal material formed the basis for the analytical modeling effort. Four single crystal primary orientations were used in the experiments: group of zone axes (001), group of zone axes (011), group of zone axes (111), and group of zone axes (213). Specific secondary orientations were also selected for the notched experiments in the optional program. Constitutive models for an overlay coating and PWA 1480 single crystal materials were developed based on isothermal hysteresis loop data and verified using thermomechanical (TMF) hysteresis loop data. A fatigue life approach and life models were developed for TMF crack initiation of coated PWA 1480. A life model was developed for smooth and notched fatigue in the option program. Finally, computer software incorporating the overlay coating and PWA 1480 constitutive and life models was developed

    Stress versus temperature dependent activation energies in creep

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    The activation energy for creep at low stresses and elevated temperatures is lattice diffusion, where the rate controlling mechanism for deformation is dislocation climb. At higher stresses and intermediate temperatures, the rate controlling mechanism changes from that of dislocation climb to one of obstacle-controlled dislocation glide. Along with this change, there occurs a change in the activation energy. It is shown that a temperature-dependent Gibbs free energy does a good job of correlating steady-state creep data, while a stress-dependent Gibbs free energy does a less desirable job of correlating the same data. Applications are made to copper and a LiF-22 mol. percent CaF2 hypereutectic salt

    On the thermodynamics of stress rate in the evolution of back stress in viscoplasticity

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    A thermodynamic foundation using the concept of internal state variables is presented for the kinematic description of a viscoplastic material. Three different evolution equations for the back stress are considered. The first is that of classical, nonlinear, kinematic hardening. The other two include a contribution that is linear in stress rate. Choosing an appropriate change in variables can remove this stress rate dependence. As a result, one of these two models is shown to be equivalent to the classical, kinematic hardening model; while the other is a new model, one which seems to have favorable characteristics for representing ratchetting behavior. All three models are thermodynamically admissible
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