Experiments on the burning of single drops of fuel

Experiments have been performed in order to measure the mass rate of consumption of single drops of liquid fuel suspended on a quartz filament and burning under various ambient conditions. The influence of increased oxidizer concentration, increased pressure, and elevated temperature in the surrounding atmosphere on mass burning rate has been studied. Comparison is made with theoretical calculations based on the concept of a heterogeneous diffusion flame, with burning rate controlled by heat and mass transfer. The influence of forced convection on burning rate and extinction of burning has also been investigated

Overall requirements for an advanced underground coal extraction system

Underground mining systems suitable for coal seams expoitable in the year 2000 are examined with particular relevance to the resources of Central Appalachia. Requirements for such systems may be summarized as follows: (1) production cost; (2)miner safety; (3) miner health; (4) environmental impact; and (5) coal conservation. No significant trade offs between production cost and other performance indices were found

Nonapproximability Results for Partially Observable Markov Decision Processes

We show that for several variations of partially observable Markov decision processes, polynomial-time algorithms for finding control policies are unlikely to or simply don't have guarantees of finding policies within a constant factor or a constant summand of optimal. Here "unlikely" means "unless some complexity classes collapse," where the collapses considered are P=NP, P=PSPACE, or P=EXP. Until or unless these collapses are shown to hold, any control-policy designer must choose between such performance guarantees and efficient computation

Bayesian Functional Data Analysis Using WinBUGS

We provide user friendly software for Bayesian analysis of functional data models using \pkg{WinBUGS}~1.4. The excellent properties of Bayesian analysis in this context are due to: (1) dimensionality reduction, which leads to low dimensional projection bases; (2) mixed model representation of functional models, which provides a modular approach to model extension; and (3) orthogonality of the principal component bases, which contributes to excellent chain convergence and mixing properties. Our paper provides one more, essential, reason for using Bayesian analysis for functional models: the existence of software.

Geothermal resources in California: potentials and problems

The technology, cost and potential of geothermal resources in California are examined. The production of power from dry stream fields is expanding in Northern California, at The Geysers, at costs that compare favorably with alternate means of generation. The possibility exists that economic production: of power can be started in the Imperial Valley, but numerous issues remain to be resolved; chief among them is the demonstration that commercially valuable aquifers indeed exist. The production of demineralized water from the geothermal fluids of the Imperial Valley depends, among other things, upon the identification of other sources of water for power plant cooling, or for reservoir reinjection, should it be necessary to avoid subsidence. It would appear that water production, without the income-producing capability of associated power generation, is not economically reasonable. The pace of geothermal development at the Geysers could probably be accelerated perhaps offering PG&E the opportunity for maintenance of adequate generating reserves should their nuclear construction program be delayed. The unknown factors and risks involved seem to preclude the Imperial Valley resource from being immediately effective in improving the power generation picture in Southern California. However, in the next decade, geothermal power could provide a useful energy increment, perhaps 10% of peak load. Associated water production could offer relief for the Imperial Valley in its predicted water quality problem. The pace of public and private development in the Imperial Valley seems incommensurately slow in relation to the potential of the resource. Geothermal power and water production is not intrinsically pollution-free, but appropriate environmental protection is possible

Montessori Education and a Neighborhood School: A Case Study of Two Early Childhood Education Classrooms

Project SYNC (Systems, Yoked through Nuanced Collaboration) details perspectives of a community of stakeholders committed to the enhancement of early childhood (i.e., prekindergarten through grade 3) education. Although there is a growing number of public-school programs informed by the Montessori philosophy, Montessori educational experiences often take place within affluent communities. SYNC aimed to enhance the prekindergarten through grade 3 educational experiences for traditionally underserved students by transforming two traditional early childhood classrooms to Montessori settings within a diverse, Title I school. Montessori pedagogy, curricula, and materials aligned with the school’s dedicated commitment to social justice. The study, one in a series, explored the impact of Montessori education on a neighborhood school community as evidenced through stakeholder opinions, project implementation, and teacher attitudes. Project data illustrate that a Montessori educational experience created learning opportunities that supported children from culturally and ethnically diverse communities in a traditional, Title I elementary school