385 research outputs found

    Electromagnetic levitation coil fabrication technique for MSFC containerless processing facilities

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    A technique is described for more reproducible fabrication of electromagnetic levitation coils. A split mandrel was developed upon which the coil is wound. After fabrication the mandrel can be disassembled to remove it from the coil. Previously, a full day was required to fabricate a levitation coil and the success rate for a functional coil was only 50 percent. About eight coils may be completed in one day using the technique developed and 95 percent of them are good levitation coils

    INDEPENDENT VALIDATION OF SENSOR MODELS IN THE COMMUNITY SENSOR MODEL PROGRAM

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    ABSTRACT As the military community continues its reliance on imagery from airborne sensors, the need to standardize sensor models for current and future sensors becomes paramount. In support of this requirement, the Community Sensor Model (CSM) program was established within the Department of Defense. Through this program, users of airborne data are provided a common interface to all essential photogrammetric functions while maintaining proprietary aspects of the sensor, through the use of shared libraries. To date, sensor model validation has ensured that all function calls return values for variables in the correct format, as specified by the Interface Control Document (ICD). The authors propose an enhanced method of validation through the use of photogrammetric processes that quantitatively evaluates a CSM's functionality on mission imagery. To support this, the validation team has developed the Generic Software Exploitation Tool (GSET) that stresses the sensor model's essential capabilities: accurate ground-to-image and image-to-ground transformations, sensor model adjustability to account for possible systematic errors, and full rigorous error propagation. One of the most critical GSET functions proposed by the authors is the photogrammetric resection. Once the sensor model is run through this test, the control and checkpoint residuals resulting from the resection will be quantitatively analyzed for modeling quality and the presence of remaining systematic errors. Results are then reported to the CSM developer as feedback and refinement of CSM development until its final delivery

    Identification of proteins from Mycobacterium tuberculosis missing in attenuated Mycobacterium bovis BCG strains.

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    A proteome approach, combining high-resolution two-dimensional electrophoresis (2-DE) with mass spectrometry, was used to compare the cellular protein composition of two virulent strains of Mycobacterium tuberculosis with two attenuated strains of Mycobacterium bovis Bacillus Calmette-Guerin (BCG), in order to identify unique proteins of these strains. Emphasis was given to the identification of M. tuberculosis specific proteins, because we consider these proteins to represent putative virulence factors and interesting candidates for vaccination and diagnosis of tuberculosis. The genome of M. tuberculosis strain H37Rv comprises nearly 4000 predicted open reading frames. In contrast, the separation of proteins from whole mycobacterial cells by 2-DE resulted in silver-stained patterns comprising about 1800 distinct protein spots. Amongst these, 96 spots were exclusively detected either in the virulent (56 spots) or in the attenuated (40 spots) mycobacterial strains. Fifty-three of these spots were analyzed by mass spectrometry, of which 41 were identified, including 32 M. tuberculosis specific spots. Twelve M. tuberculosis specific spots were identified as proteins, encoded by genes previously reported to be deleted in M. bovis BCG. The remaining 20 spots unique for M. tuberculosis were identified as proteins encoded by genes that are not known to be missing in M. bovis BCG

    Towards the proteome of the marine bacterium Rhodopirellula baltica: mapping the soluble proteins

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    The marine bacterium Rhodopirellula baltica, a member of the phylum Planctomycetes, has distinct morphological properties and contributes to remineralization of biomass in the natural environment. On the basis of its recently determined complete genome we investigated its proteome by 2-DE and established a reference 2-DE gel for the soluble protein fraction. Approximately 1000 protein spots were excised from a colloidal Coomassie-stained gel (pH 4-7), analyzed by MALDI-MS and identified by PMF. The non-redundant data set contained 626 distinct protein spots, corresponding to 558 different genes. The identified proteins were classified into role categories according to their predicted functions. The experimentally determined and the theoretically predicted proteomes were compared. Proteins, which were most abundant in 2-DE gels and the coding genes of which were also predicted to be highly expressed, could be linked mainly to housekeeping functions in glycolysis, tricarboxic acid cycle, amino acid biosynthesis, protein quality control and translation. Absence of predictable signal peptides indicated a localization of these proteins in the intracellular compartment, the pirellulosome. Among the identified proteins, 146 contained a predicted signal peptide suggesting their translocation. Some proteins were detected in more than one spot on the gel, indicating post-translational modification. In addition to identifying proteins present in the published sequence database for R. baltica, an alternative approach was used, in which the mass spectrometric data was searched against a maximal ORF set, allowing the identification of four previously unpredicted ORFs. The 2-DE reference map presented here will serve as framework for further experiments to study differential gene expression of R. baltica in response to external stimuli or cellular development and compartmentalization

    Theoretical study of the absorption spectra of the lithium dimer

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    For the lithium dimer we calculate cross sections for absorption of radiation from the vibrational-rotational levels of the ground X [singlet Sigma g +] electronic state to the vibrational levels and continua of the excited A [singlet Sigma u +] and B [singlet Pi u] electronic states. Theoretical and experimental data are used to characterize the molecular properties taking advantage of knowledge recently obtained from photoassociation spectroscopy and ultra-cold atom collision studies. The quantum-mechanical calculations are carried out for temperatures in the range from 1000 to 2000 K and are compared with previous calculations and measurements.Comment: 20 pages, revtex, epsf, 6 fig

    Project ThaiPASS: international outreach blending astronomy and Python

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    We present our outreach program, the Thailand–UK Python+Astronomy Summer School (ThaiPASS), a collaborative project comprising UK and Thai institutions and assess its impact and possible application to schools in the United Kingdom. Since its inception in 2018, the annual ThaiPASS has trained around 60 Thai high-school students in basic data handling skills using Python in the context of various astronomy topics, using current research from the teaching team. Our impact assessment of the 5 day summer schools shows an overwhelmingly positive response from students in both years, with over 80% of students scoring the activities above average in all activities but one. We use this data to suggest possible future improvements. We also discuss how ThaiPASS may inspire further outreach and engagement activities within the UK and beyond

    Volunteering in a hybrid institutional and organizational environment: an emerging research agenda

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    Traditionally, volunteers are core participants in classic voluntary associations; however, the organizational context of volunteering has changed significantly in recent decades through the proliferation of new and hybrid settings of participation that mingle roles and rationalities of civil society, state and market. In this chapter, I examine the consequences of this organizational change for the nature and functions of volunteering by means of a literature review
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