5,233 research outputs found

    Quantitative nondestructive evaluation of materials and structures

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    An experimental investigation was undertaken to quantify damage tolerance and resistance in composite materials impacted using the drop-weight method. Tests were conducted on laminates of several different carbon-fiber composite systems, such as epoxies, modified epoxies, and amorphous and semicrystalline thermoplastics. Impacted composite specimens were examined using destructive and non-destructive techniques to establish the characteristic damage states. Specifically, optical microscopy, ultrasonic, and scanning electron microscopy techniques were used to identify impact induced damage mechanisms. Damage propagation during post impact compression was also studied

    Rapid detection and quantification of features such as damage or flaws in composite and metallic structures

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    An apparatus, system, and method for non-destructible evaluation (NDE) of a material use thermography to rapidly detect and/or generally locate a feature such as, for example, damage or a defect in the material. The apparatus, system, and method also use ultrasound to specifically locate the feature in the material for quantification and/or evaluation either by an operator or by an external device suited for such purpose. Accordingly, the apparatus, system and method are particularly useful for NDE in applications such as the analysis of the structure of an aircraft, for example, in which the scale of the material to be analyzed is large, thus requiring the rapid NDE afforded by thermography, and in which quantification and/or evaluation of a feature must be performed with precision, thus requiring the relatively high-resolution NDE afforded by ultrasound

    DEVELOPMENT OF A TL-3 F-SHAPE TEMPORARY CONCRETE MEDIAN BARRIER

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    A temporary concrete median barrier (CMB) was designed and tested for compliance under the Test Level 3 (TL-3) guidelines specified in the Recommended Procedures for the Safety Performance Evaluation of Highway Features, National Cooperative Highway Research Program (NCHRP) Report No. 350. The barrier is built to the new metric standards and has a traditional pin and loop configuration for interconnection. The objective of this research project was to develop and evaluate a standardized, temporary concrete barrier design while addressing the concerns for safety, economy, structural integrity, constructability, ease of installation, and maintenance. The resulting F-shape barrier segment is 3,800-mm long, a length that reduced the number of connections while limiting the weight of the barriers to ease handling. Full-scale crash testing demonstrated several critical design features. First, the connections need to be tight initially as practicable to limit deformation and rotation of the barriers,. Secondly, the pin needs to restrain the longitudinal barrier forces. Full-scale compliance testing of the final design demonstrated that the barrier was capable of successfully redirecting the 2000-kg vehicle. The vehicle demonstrated significant roll after contact with the barrier, which is evidenced in a majority of other concrete barrier tests. This barrier provides economical work zone protection applicable in a variety of situations, where TL-3 test criteria is warranted

    Saliva Ontology: An ontology-based framework for a Salivaomics Knowledge Base

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    <p>Abstract</p> <p>Background</p> <p>The Salivaomics Knowledge Base (SKB) is designed to serve as a computational infrastructure that can permit global exploration and utilization of data and information relevant to salivaomics. SKB is created by aligning (1) the saliva biomarker discovery and validation resources at UCLA with (2) the ontology resources developed by the OBO (Open Biomedical Ontologies) Foundry, including a new Saliva Ontology (SALO).</p> <p>Results</p> <p>We define the Saliva Ontology (SALO; <url>http://www.skb.ucla.edu/SALO/</url>) as a consensus-based controlled vocabulary of terms and relations dedicated to the salivaomics domain and to saliva-related diagnostics following the principles of the OBO (Open Biomedical Ontologies) Foundry.</p> <p>Conclusions</p> <p>The Saliva Ontology is an ongoing exploratory initiative. The ontology will be used to facilitate salivaomics data retrieval and integration across multiple fields of research together with data analysis and data mining. The ontology will be tested through its ability to serve the annotation ('tagging') of a representative corpus of salivaomics research literature that is to be incorporated into the SKB.</p

    Comparative Effectiveness and Safety of Empiric Ampicillin plus Gentamicin or Empiric Piperacillin-Tazobactam in the Neonatal Intensive Care Unit

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    BACKGROUND: This study was designed to assess piperacillin tazobactam (PT) as an alternative to ampicillin and gentamicin (AG) in neonates with suspected systemic infection. METHODS: A retrospective, unmatched population of AG (2007-2009) and PT (2009-2012) exposed infants were evaluated for initial effectiveness, adverse events, and subsequent morbidities or mortality. Data included gestational age, birth weight, sex, Apgar score, length of hospital stay, glomerular filtration rate for days 1 and 2, duration on mechanical ventilation, duration on oxygen therapy, incidence of sepsis (blood or cerebrospinal fluid culture positive), incidence of ventilator associated pneumonia, and incidence of necrotizing enterocolitis. All positive blood cultures during the study period were reviewed. Data about specific microorganisms and sensitivity to antibiotics were RESULTS: No significant differences in demographics or initial Apgar scores were noted. There were no significant differences in systemic rash or diaper rash. PT was associated with higher glomerular filtration rate on day two. Four infants had early onset sepsis with ampicillin resistant E. coli. One of these, in the PT group, had intermediate sensitivity to gentamicin as well. CONCLUSION: Use of PT as the initial empiric antibiotic was not associated with increased adverse outcomes. The challenge of ampicillin resistant Escherichia coli should encourage others to consider this change

    Drawing Boundaries

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    In “On Drawing Lines on a Map” (1995), I suggested that the different ways we have of drawing lines on maps open up a new perspective on ontology, resting on a distinction between two sorts of boundaries: fiat and bona fide. “Fiat” means, roughly: human-demarcation-induced. “Bona fide” means, again roughly: a boundary constituted by some real physical discontinuity. I presented a general typology of boundaries based on this opposition and showed how it generates a corresponding typology of the different sorts of objects which boundaries determine or demarcate. In this paper, I describe how the theory of fiat boundaries has evolved since 1995, how it has been applied in areas such as property law and political geography, and how it is being used in contemporary work in formal and applied ontology, especially within the framework of Basic Formal Ontology

    A domain ontology for the non-coding RNA field

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    Identification of non-coding RNAs (ncRNAs) has been significantly enhanced due to the rapid advancement in sequencing technologies. On the other hand, semantic annotation of ncRNA data lag behind their identification, and there is a great need to effectively integrate discovery from relevant communities. To this end, the Non-Coding RNA Ontology (NCRO) is being developed to provide a precisely defined ncRNA controlled vocabulary, which can fill a specific and highly needed niche in unification of ncRNA biology

    Structure and physical properties of GexAsySe1−x−y glasses with the same mean coordination number of 2.5

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    We have prepared and analyzed five different compositions of GexAsySe1−x−yglasses that have the same mean coordination number (MCN) of 2.5 in order to understand whether MCN or chemical composition has the dominant effect on the physical properties of the glass. Density measurements showed a maximum for the chemically stoichiometric Ge12.5As25Se62.5 sample and suggested that some rearrangement of the atoms was occurring as one atom substituted for another. The measurements of Tg, however, showed that the glasses had almost same glass transition temperature and suggested that the glassnetwork connectivity did not change much with composition. Although Raman scattering and x-ray photoelectron spectra of the glasses indicate that the percentage of the different structural units changes with the composition, there was no evidence of the existence of structural units that could change the overall connectivity of the glassnetwork. Therefore, we concluded that glasses with same MCN but different composition have similar glassnetwork connectivity, and that chemical composition has only a secondary effect on the physical properties of the glasses.This research was partly supported by the Australian Research Council through its Centres of Excellence and Discovery DP110102753 programs

    The Non-Coding RNA Ontology : a comprehensive resource for the unification of non-coding RNA biology

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    In recent years, sequencing technologies have enabled the identification of a wide range of non-coding RNAs (ncRNAs). Unfortunately, annotation and integration of ncRNA data has lagged behind their identification. Given the large quantity of information being obtained in this area, there emerges an urgent need to integrate what is being discovered by a broad range of relevant communities. To this end, the Non-Coding RNA Ontology (NCRO) is being developed to provide a systematically structured and precisely defined controlled vocabulary for the domain of ncRNAs, thereby facilitating the discovery, curation, analysis, exchange, and reasoning of data about structures of ncRNAs, their molecular and cellular functions, and their impacts upon phenotypes. The goal of NCRO is to serve as a common resource for annotations of diverse research in a way that will significantly enhance integrative and comparative analysis of the myriad resources currently housed in disparate sources. It is our belief that the NCRO ontology can perform an important role in the comprehensive unification of ncRNA biology and, indeed, fill a critical gap in both the Open Biological and Biomedical Ontologies (OBO) Library and the National Center for Biomedical Ontology (NCBO) BioPortal. Our initial focus is on the ontological representation of small regulatory ncRNAs, which we see as the first step in providing a resource for the annotation of data about all forms of ncRNAs. The NCRO ontology is free and open to all users
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