Building course calendars in vocational agriculture

In the past, teachers have followed prepared guides for course calendars or have borrowed course calendars from experienced teachers and have been encouraged to use these guides and tried calendars, but these practices can no longer be justified. Conscientious, progressive teachers welcome the opportunity to assume the major responsibility for planning course calendars based on the needs of their students. These teachers, however, encounter difficulties in reaching decisions on what jobs to teach, when to teach the jobs selected, how much time to schedule for each job, and other problems. Beginning teachers are frequently pressed for time in developing course calendars and, as a result, resort to borrowing course calendars from neighboring teachers. Some teachers never plan course calendars, but teach jobs as they arise or plan from week to week. An analysis of many course calendars in use today indicates that these calendars are based on fact and sound judgment. Both beginning and experienced teachers have expressed a need for solutions to problems included in this study. The teacher training staff has not provided adequate opportunity for experience in planning course calendars for students enrolled in the Agricultural Education Curriculum. One reason for this is the lack of sufficient information on course building to develop confidence and competence In trainees. This lack of training may be a factor in causing beginning teachers to turn to neighboring teachers and printed guides in developing their course calendars. Some course calendars seem to be built around the subject matter available. Subject matter materials should not determine the content of course calendars since these materials are designed to be used as an aid in teaching the jobs found in the course calendars. Information collected and organized in this study should be helpful in planning future subject matter publications to meet more adequately instructional needs. Supervisors have rendered limited service to teachers in developing course calendars. Perhaps one reason for this is that supervisors do not have adequate information to give the type of help they would like to give. This study should supply some of the needed information

Kinetics of the monomer-monomer surface reaction model

The two-dimensional monomer-monomer (AB) surface reaction model without diffusion is considered for infinitesimal, finite, and infinite reaction rates k. For equal reactant adsorption rates, in all cases, simulations reveal the same form of slow poisoning, associated with clustering of reactants. This behavior is also the same as that found in simulations of the two-dimensional voter model studied in interacting-particle systems theory. The voter model can also be obtained from the dimer-dimer or monomer-dimer surface reaction models with infinitesimal reaction rate. We provide a detailed elucidation of the slow poisoning kinetics via an analytic treatment for the k=0+ AB reaction and the voter models. This analysis is extended to incorporate the effects of place-exchange diffusion which slows, but does not prevent poisoning. We also show that the k=0+ AB reaction with no diffusion is equivalent to the voter model with diffusion at rate 1/2. Identical behavior of the monomer-monomer reaction and the voter model is also found in an ‘‘epidemic’’ analysis, where one considers the evolution of a surface poisoned by one species, except for a small patch. Finally, we apply our findings to elucidate the behavior of the monomer-dimer surface reaction model for small reaction rates

Interface propagation and nucleation phenomena for discontinuous poisoning transitions in surface-reaction models

Here, we consider discontinuous nonequilibrium phase transitions to poisoned or ‘‘adsorbing’’ states in lattice-gas models of surface reactions. Specifically, we examine the monomer or CO-poisoning transition in the Ziff-Gulari-Barshad monomer-dimer reaction model for CO oxidation, modified to include adspecies diffusion. For CO pressures below the poisoning transition, we first characterize the propagation of and fluctuations at an interface between reactive and CO-poisoned states. Here, we utilize ideas from spatial contact models, reaction-diffusion theory, and kinetic roughening theory. Evolution is described by the Kardar-Parisi-Zhang equation, but with the nonlinearity and kinetic surface tension vanishing on approaching the transition. Next, again for CO pressures below the transition, we consider the evolution of a ‘‘nucleus’’ of the reactive state embedded in the CO-poisoned state, now exploiting concepts from epidemic theory. We elucidate the divergence and ‘‘sharpening’’ of the critical size of this nucleus, both approaching the transition and with increasing adspecies diffusion rates. The deviation from mean-field divergence approaching the transition is related to the vanishing of the kinetic surface tension. The sharpening is related to the reduced influence of fluctuations. Throughout this contribution, we focus on providing a unifying framework that can describe both the fluctuation-dominated behavior of the lattice-gas model for low adspecies diffusion rates, and the crossover to the deterministic mean-field behavior for high diffusion rates where the adlayer is well mixed or randomized

Wish Me A Rainbow

Title Onlyhttps://scholarsjunction.msstate.edu/cht-sheet-music/6814/thumbnail.jp

Tammy

Photograph of Debbie Reynoldshttps://scholarsjunction.msstate.edu/cht-sheet-music/11523/thumbnail.jp

Paper Session II-B - NASA\u27s Heavy-Lift Cargo Launch Vehicle Needs and Options for the Post 2000 Period

This paper presents the HLLV requirements, architectures and concepts. The paper focuses on vehicle options and facility requirements/impacts associated with unmanned heavy-lift cargo vehicles needed to assure future missions can be achieved

Stuff Like That There.

Photo of Betty Hutton; Green backgroundhttps://scholarsjunction.msstate.edu/cht-sheet-music/10351/thumbnail.jp