Materials research for aircraft fire safety

The thermochemical and flammability characteristics of two polymeric composites currently in use and seven others being considered for use as aircraft interior panels are described. The properties studied included: (1) limiting oxygen index of the composite constituents; (2) fire containment capability of the composite; (3) smoke evolution from the composite; (4) thermogravimetric analysis; (5) composition of the volatile products of thermal degradation; and (6) relative toxicity of the volatile products of pyrolysis. The performance of high-temperature laminating resins such as bismaleimides is compared with the performance of phenolics and epoxies. The relationship of increased fire safety with the use of polymers with high anaerobic char yield is shown. Processing parameters of the state-of-the-art and the advanced bismaleimide composites are detailed

Apollo command module mockup flammability tests

Apollo command module mockup flammability tests using three different atmosphere

Full-scale aircraft cabin flammability tests of improved fire-resistant materials, test series 2

Full-scale aircraft flammability tests in which the effectiveness of new fire-resistant materials was evaluated by comparing their burning characteristics with those of other fire-resistant aircraft materials were described. New-fire-resistant materials that are more economical and better suited for aircraft use than the previously tested fire-resistant materials were tested. The fuel ignition source for one test was JP-4; a smokeless fuel was used for the other test. Test objectives, methods, materials, and results are presented and discussed. The results indicate that, similar to the fire-resistant materials tested previously, the new materials decompose rather than ignite and do not support fire propagation. Furthermore, the new materials did not produce a flash fire

Toxic Substances

This part of the CBP Synthesis Report summarizes and integrates the research findings and reconnnendations of 13 projects of the Chesapeake Bay Toxic Substances Program performed between July 1978 and October 1981. The following sections describe research on potentially toxic substances, or toxicants, in water-sediments and selected biota. The subjects considered include a brief review of metals, their sources, distribution and behavior, and then a review of sources and distribution of organic chemicals. Finally, information concerning the significance of toxicants in the- Bay and their pattern of enrichment is provided. Most information synthesized in this report can be traced to its origin in scientific project reports listed in Appendix A.https://scholarworks.wm.edu/vimsbooks/1097/thumbnail.jp

Brucella 'HOOF-Prints': strain typing by multi-locus analysis of variable number tandem repeats (VNTRs)

BACKGROUND: Currently, there are very few tools available for subtyping Brucella isolates for epidemiological trace-back. Subtyping is difficult because of the genetic homogeneity within the genus. Sequencing of the genomes from three Brucella species has facilitated the search for DNA sequence variability. Recently, hypervariability among short tandem repeat sequences has been exploited for strain-typing of several bacterial pathogens. RESULTS: An eight-base pair tandem repeat sequence was discovered in nine genomic loci of the B. abortus genome. Eight loci were hypervariable among the three Brucella species. A PCR-based method was developed to identify the number of repeat units (alleles) at each locus, generating strain-specific fingerprints. None of the loci exhibited species- or biovar-specific alleles. Sometimes, a species or biovar contained a specific allele at one or more loci, but the allele also occurred in other species or biovars. The technique successfully differentiated the type strains for all Brucella species and biovars, among unrelated B. abortus biovar 1 field isolates in cattle, and among B. abortus strains isolated from bison and elk. Isolates from the same herd or from short-term in vitro passage exhibited little or no variability in fingerprint pattern. Sometimes, isolates from an animal would have multiple alleles at a locus, possibly from mixed infections in enzootic areas, residual disease from incomplete depopulation of an infected herd or molecular evolution within the strain. Therefore, a mixed population or a pool of colonies from each animal and/or tissue was tested. CONCLUSION: This paper describes a new method for fingerprinting Brucella isolates based on multi-locus characterization of a variable number, eight-base pair, tandem repeat. We have named this technique "HOOF-Prints" for Hypervariable Octameric Oligonucleotide Finger-Prints. The technique is highly discriminatory among Brucella species, among previously characterized Brucella strains, and among unrelated field isolates that could not be differentiated by classical methods. The method is rapid and the results are reproducible. HOOF-Printing will be most useful as a follow-up test after identification by established methods since we did not find species-specific or biovar-specific alleles. Nonetheless, this technology provides a significant advancement in brucellosis epidemiology, and consequently, will help to eliminate this disease worldwide

Theoretical studies of the historical development of the accounting discipline: a review and evidence

Many existing studies of the development of accounting thought have either been atheoretical or have adopted Kuhn's model of scientific growth. The limitations of this 35-year-old model are discussed. Four different general neo-Kuhnian models of scholarly knowledge development are reviewed and compared with reference to an analytical matrix. The models are found to be mutually consistent, with each focusing on a different aspect of development. A composite model is proposed. Based on a hand-crafted database, author co-citation analysis is used to map empirically the entire literature structure of the accounting discipline during two consecutive time periods, 1972–81 and 1982–90. The changing structure of the accounting literature is interpreted using the proposed composite model of scholarly knowledge development

Search for Light Gluinos via the Spontaneous Appearance of pi+pi- Pairs with an 800 GeV/c Proton Beam at Fermilab

We searched for the appearance of pi+pi- pairs with invariant mass greater than 648 MeV in a neutral beam. Such an observation could signify the decay of a long-lived light neutral particle. We find no evidence for this decay. Our null result severely constrains the existence of an R0 hadron, which is the lightest bound state of a gluon and a light gluino, and thereby also the possibility of a light gluino. Depending on the photino mass, we exclude the R0 in the mass and lifetime ranges of 1.2 -- 4.6 GeV and 2E-10 -- 7E-4 seconds, respectively. (To Appear in Phys. Rev. Lett.)Comment: Documentstyle aps,epsfig,prl (revtex), 6 pages, 7 figure

Multicenter evaluation of emergency department treatment for children and adolescents with Crohn's disease according to race/ethnicity and insurance payor status

Background Racial and socioeconomic disparities exist in the treatment and outcomes of children and adults with Crohn's disease (CD). This study investigated the impact of race and insurance status on emergency department (ED) evaluation and treatment among children with CD in the United States. Methods Data from the Pediatric Health Information System included ED visits between January 2007 and December 2013 for patients aged ó21 years with a primary diagnosis of CD, or a secondary diagnosis of CD plus a primary CD-related diagnosis. Analyses were performed using mixed-effects logistic regression. Results Subjects included 2618 unique patients (black, 612 [23%]; white, 2006 [77%]) with 3779 visits from 38 hospitals, a median age of 14.0 ñ 4.0 years, and 50% male. White children had a higher median neighborhood income and were more likely to have private insurance (57% vs 30%; P < 0.001). Emergency department visits for privately insured patients had higher odds of complete blood count (odds ratio [OR], 1.43; 95% CI, 1.08-1.90) and C-reactive protein/erythrocyte sedimentation rate (OR, 1.39; 95% CI, 1.06-1.82) vs Medicaid insured. Visits for white children had higher odds of receiving antiemetics (OR, 1.52; 95% CI, 1.06-2.17) vs black children. The proportion of patients with repeat visits was greater for black children (33%) than white children (22%; P < 0.001) and greater for Medicaid-insured (27%) than privately insured patients (21%; P < 0.01). Conclusions This cross-sectional database study demonstrated that black children and those with Medicaid insurance made more ED visits and received somewhat fewer treatments, which may be explained by greater use of the ED for routine care. An opportunity exists for better outpatient management of children with IBD so that nonemergent problems are more effectively handled

Light Gluino Search for Decays Containing pi+pi- or pi0 from a Neutral Hadron Beam at Fermilab

We report on two null searches, one for the spontaneous appearance of $\pi^+\pi^-$ pairs, another for a single $\pi^0$, consistent with the decay of a long-lived neutral particle into hadrons and an unseen neutral particle. For the lowest level gluon-gluino bound state, known as the $R^0$, we exclude the decays $R^0\to \pi^+\pi^-\tilde{\gamma}$ and $R^0\to \pi^0\tilde{\gamma}$ for the masses of $R^0$ and $\tilde{\gamma}$ in the theoretically allowed range. In the most interesting $R^0$ mass range, $\leq 3 GeV/c^2$, we exclude $R^0$ lifetimes from $3\times 10^{-10}$ seconds to as high as $10^{-3}$ seconds, assuming perturbative QCD production for the $R^0$.Comment: 15 pages, 7 figure