5,371 research outputs found
Debugging tasked Ada programs
The applications for which Ada was developed require distributed implementations of the language and extensive use of tasking facilities. Debugging and testing technology as it applies to parallel features of languages currently falls short of needs. Thus, the development of embedded systems using Ada pose special challenges to the software engineer. Techniques for distributing Ada programs, support for simulating distributed target machines, testing facilities for tasked programs, and debugging support applicable to simulated and to real targets all need to be addressed. A technique is presented for debugging Ada programs that use tasking and it describes a debugger, called AdaTAD, to support the technique. The debugging technique is presented together with the use interface to AdaTAD. The component of AdaTAD that monitors and controls communication among tasks was designed in Ada and is presented through an example with a simple tasked program
The Effect of the Sequence of Dilution upon the Potential Brightness of Coated Board
The purpose of this study has been to determine the influence of the sequence of dilution upon the potential brightness of coated board. The sequence of diluting a coating slurry was varied and its effect upon the brightness of doubly coated board was noted. Besides the measurement of brightness, the coat weight and scattering coefficients were determined. The brightness was determined on the standard I.P.C. Brightness meter. The coat weight was determined from a modification of Tappi Standard T-627m58 while the scattering coefficient was determined from a table of brightness and scattering power.
The results indicated that diluting a coating slurry after mixing the adhesive and pigment together has the least detrimental effect on brightness, while diluting the adhesive before mixing with the pigment has the most detrimental effect upon the brightness. The above findings are explained in terms of varying degrees of pigment and adhesive bonding
High Heat Flux Testing Facilities and an Electrothermal-Arc Plasma Source for Plasma-Material Interaction Studies and Diagnostic Development
Tokamak plasma-facing components experience significant stresses from plasma-material interactions (PMI) due to cyclic high thermal loads, plasma exposure, and neutron irradiation. As the field progresses to reactor-level power fluxes, the harsh fusion environment demands much of plasma-facing materials.
Chapter 1 introduces plasma-material interactions and the condition plasma-facing components are expected to endure. While plasma exposure and neutron radiation damage are introduced, the synergistic effects of cyclic high thermal loads under plasma exposure are focused on. This motivates the need for plasma-facing materials studies.
Chapter 2 gives a brief overview of many high heat flux test facilities worldwide. Three prominent high heat flux devices are discussed, including (1) the linear plasma device Magnum-PSI, (2) the electron beam facility JUDITH-II, and (3) the electrothermal-arc plasma source SIRENS. This motivates the high heat flux testing of materials in a highly controlled, repeatable, transient-level plasma exposure and plasma heat flux conditions. This is the motivation for the project undertaken at Oak Ridge National Laboratory.
Chapter 3 is the project undertaken and is the main focus of this report. At Oak Ridge National Laboratory, an electrothermal-arc plasma source (ET-Arc) was modified and rebuilt in the laser diagnostics lab. The motivation for this project is twofold: (1) to develop two laser diagnostics, a “Portable Diagnostic Package” (PDP) which characterizes the plasma spectroscopically and Digital Holography (DH) which measures the in situ erosion of the target; and (2) to use the ET-Arc source and DH to conduct erosion studies under transient-level (~GW m-2) heat fluxes. The modifications, upgrades, and diagnostic capabilities are discussed as well as future work
Measurement of temperature profiles in hot gases and flames
Computer program was written for calculation of molecular radiative transfer from hot gases. Shape of temperature profile was approximated in terms of simple geometric forms so profile could be characterized in terms of few parameters. Parameters were adjusted in calculations using appropriate radiative-transfer expression until best fit was obtained with observed spectra
Market Values in Education: A Case Study of its Effect on the Principal\u27s Model for School Governance in Alberta
Political bodies, facing, increased pressures to improve the quality of education offered to students, are shifting to a philosophy that imposes large scale market forces such as parental choice and school competition onto educational systems in order to coerce school improvement. This shift may be prompting school-based administrators to shift school governance practices to reflect these market values. This shift, occurring in Alberta (Canada), is founded in government policy that articulates the option of educational choice for parents. Presently the government policy promotes these market values in education by providing full funding to public, separate, and charter schools, and partial funding to accredited private schools thus creating an atmosphere of competition and parental choice between schools. Public choice theory, emanating from neoclassical economics, is the economics model that this model operates within the educational system. A total of seventeen Alberta public, separate, charter, and private school principals were interviewed in this multi-site case study investigating the shift toward market values in education. The purpose of this study was to determine if principals perceived a change toward a market model, and to gain insight into what might be the implications for principals\u27 school governance as a result of the application of market forces. Specifically, the study examined what these principals believe are the effects of the application of market forces on the governance of their schools. Findings of this study support the contention that a political movement is at the root of this reform. As part of this reform, the findings suggest that an educational system of choice is developing in Alberta, and one of the results of this is increased competition between schools and school systems. Also emanating from this evolving market based educational system is a devolved school governance structure that includes changes to the structures of finance, school organization, and decision making. Consequently, successful school principals are requiring new knowledge and skills in order to lead their schools. Specifically, the findings imply that the principal of a school operating in a market based educational milieu will require enhanced human resources, marketing, leadership, and management skills
Rigid open-cell polyurethane foam for cryogenic insulation
Lightweight polyurethane foam assembled in panels is effective spacer material for construction of self-evacuating multilayer insulation panels for cryogenic liquid tanks. Spacer material separates radiation shields with barrier that minimizes conductive and convective heat transfer between shields
Distribution and Relative Abundance of Butterflyfishes and Angelfishes Across a Lagoon and Barrier Reef, Andros Island, Bahamas
Juveniles of Chaetodon capistratus, C. striatus, C. ocellatus, C. sedentarius, Pomacanthus arcuatus, P. paru, Holacanthus ciliaris, and H. tricolor occurred in the shallow lagoon habitats. Adults and subadults of these species were associated with the deeper barrier reef and seaward platform habitats. C. aculeatus occurred only on the outer seaward platform. In strip transects at a seaward platform site, C. capistratus and H. tricolor were found with significantly greater abundance than P. paru and C. striatus
Lightweight multilayer insulation system Final report
Self evacuating multilayer insulation panel systems for liquid hydrogen space tankag
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