The Vapor-Liquid and Liquid-Liquid Phase Equilibria for the Partially Miscible System Methanol-Cyclohexane

By use of techniques of previous workers for determining liquid-liquid equilibrium and through the use of a circulation still, the complete phase diagram for the partially miscible system, methanol-cyclohexane, was determined. Tile accuracy of earlier liquid-liquid phase data was not improved upon although it was closely approximated. The critical solution temperature was found to be 46.4 degrees C., which is within the range of temperatures reported in earlier measurements. Activity coefficients of methanol and cyclohexane were calculated from the phase boundaries of the boiling point diagram determined in the present investigation. These activity coefficients were in agreement with the Gibbs-Duhem equation and with the theoretically predicted activity coefficients of the van Laar and Margules equations. Vapor-liquid phase data previously available was limited to the azeotrope boiling temperature reported to be 54.2 degrees C

Impact of rod projectiles against multiple- sheet targets

Blunt hypervelocity projectile lift-drag ratio and impact velocity effects on target penetration and impact damag

The Vapor-Liquid and Liquid-Liquid Phase Equilibria for the Partially Miscible System Methanol-Cyclohexane

By use of techniques of previous workers for determining liquid-liquid equilibrium and through the use of a circulation still, the complete phase diagram for the partially miscible system, methanol-cyclohexane, was determined. Tile accuracy of earlier liquid-liquid phase data was not improved upon although it was closely approximated. The critical solution temperature was found to be 46.4 degrees C., which is within the range of temperatures reported in earlier measurements. Activity coefficients of methanol and cyclohexane were calculated from the phase boundaries of the boiling point diagram determined in the present investigation. These activity coefficients were in agreement with the Gibbs-Duhem equation and with the theoretically predicted activity coefficients of the van Laar and Margules equations. Vapor-liquid phase data previously available was limited to the azeotrope boiling temperature reported to be 54.2 degrees C

Life sciences on-line: A study in hypermedia application

The main objective was to determine the feasibility of using a computer-based interactive information recall module for the Life Sciences Project Division (LSPD) at NASA, Johnson Space Center. LSPD personnel prepare payload experiments to test and monitor physiological functions in zero gravity. Training refreshers and other types of online help are needed to support personnel in their tasks during mission testing and in flight. Results of a survey of other hypermedia and multimedia developers and lessons learned by the developer of the LSPD prototype module are presented. Related issues and future applications are also discussed and further hypermedia development within the LSPD is recommended

Negotiating for Democratic Communities in Schools: Principals’ Perspectives

This study explored the strategic use of negotiating as a tool for creating and enhancing democratic communities. Principals have been described as an important unit of analysis in examining leadership practice

New Graduate Nurses’ Perceptions and Applications of Participating in a Multipatient Simulation

Students can benefit from simulation in-that sometimes during clinicals they don\u27t get to provide care where they are solely responsible for the patient. Students need to learn to prioritize and provide care for their patients. Learn students’ perceptions and their practical application of their simulated learning experience

Developing Communities of Instructional Practice: Lessons From Cincinnati and Philadelphia

Over the past several years, education reformers have increasingly invested in the development of communities within schools as a central strategy to improve teaching and student learning. These communities come in various guises, including small schools, small learning communities, and teacher teams. Two assumptions about how these communities will enhance the quality of instruction underlie the push for these more intimate learning environments. First, supporters believe that teachers will get to know their students better and therefore be more able to respond to students’ learning needs. Second, advocates contend that small communities will encourage teachers to collaborate more in order to improve their instructional practices. Thus, the theory of action underlying the development of teacher communities is that the fostering of these kinds of teacher communities will instigate improvements in the quality of instruction, which will lead to enhanced student learning. This issue of CPRE Policy Briefs examines the merit of these assumptions and the conditions under which communities of teachers can improve their instructional practices and bring about enhanced student learning. The lessons for policymakers contained in this Brief come from large-scale evaluations of two major district reform initiatives — one in Philadelphia, Pennsylvania and the other in Cincinnati, Ohio — that were designed to foster the development of instructionally focused communities. The research from these two very different settings indicates that only under certain conditions will teacher communities flourish into communiDeveloping Communities of Instructional Practice: Lessons from Cincinnati and Philadelphia By Jonathan A. Supovitz and Jolley Bruce Christman ties engaged in instructional improvement. The findings suggest that in order for an investment in communities to pay off in widespread improvement in student learning, particular kinds of teacher communities are needed: those that are focused on improving the instructional core of schooling and provided with the necessary strategies, structures, and supports. With more specific guidance that helps teachers to hone their instructional craft knowledge, policymakers can foster communities of instructional practice

A focused ion beam secondary ion mass spectrometry system

This article describes a Ga+ focused ion beam secondary ion mass spectroscopy system, and measures several quantities of interest to aid in interpreting secondary ion mass spectroscopy results. We have measured sputter yields and rates, estimated the instrument efficiency, and calculated useful yields and practical sensitivities for a variety of elements used in the semiconductor industry. We have performed measurements at the system base pressure, and have also introduced oxygen and iodine to determine any enhancement effects

Making the Most of Interim Assessment Data: Lessons from Philadelphia

Under No Child Left Behind, urban school districts have increasingly turned to interim assessments, administered at regular intervals, to help gauge student progress in advance of annual state exams. These assessments have spawned growing debate among educators, assessment experts, and the testing industry: are they worth the significant investment of money and time? In Making the Most of Interim Assessment Data: Lessons from Philadelphia, Research for Action (RFA) weighs in on this issue. The School District of Philadelphia (SDP) was an early adopter of interim assessments, implementing the exams in 2003. Unlike teachers in some other regions, Philadelphia elementary and middle grades teachers rated these 'Benchmark' assessments highly. However, the study found that enthusiasm did not necessarily correlate with higher rates of student achievement. What did predict student success were three factors -- instructional leadership, collective responsibility, and use of the SDP's Core Curriculum. The report underscores the value of investment in ongoing data interpretation that emphasizes teachers' learning within formal instructional communities, such as grade groups of teachers. This research was funded by the Spencer Foundation and the William Penn Foundation