2,499 research outputs found

    In situ mass analysis of particles by surface ionization mass spectrometry

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    A qualitative study of the application of surface ionization and mass spectrometry to the in situ detection and constituent analysis of atmospheric particles was conducted. The technique consists of mass analysis of ions formed as a result of impingement of a stream of particles on a hot filament where, it is presumed, surface ionization takes place. Laboratory air particles containing K, Ca, and possibly hydrocarbons were detected. Other known particles such as Al2O3, Pb(NO3)2, and Cr2O3 were analyzed by detecting the respective metal atoms making up the particles. In some cases, mass numbers indicative of compounds making up the particles were detected showing surface ionization of particles sometimes leads to chemical analysis as well as to elemental analysis. Individual particles were detected, and it was shown that the technique is sensitive to Al2O3 particles with a mass of a few nanograms

    Effect of display size on utilization of traffic situation display for self-spacing task

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    The weather radar cathode ray tube (CRT) is the prime candidate for presenting cockpit display of traffic information (CDTI) in current, conventionally equipped transport aircraft. Problems may result from this, since the CRT size is not optimized for CDTI applications and the CRT is not in the pilot's primary visual scan area. The impact of display size on the ability of pilots to utilize the traffic information to maintain a specified spacing interval behind a lead aircraft during an approach task was studied. The five display sizes considered are representative of the display hardware configurations of airborne weather radar systems. From a pilot's subjective workload viewpoint, even the smallest display size was usable for performing the self spacing task. From a performane viewpoint, the mean spacing values, which are indicative of how well the pilots were able to perform the task, exhibit the same trends, irrespective of display size; however, the standard deviation of the spacing intervals decreased (performance improves) as the display size increased. Display size, therefore, does have a significant effect on pilot performance

    Men\u27s and Women\u27s Definitions of Good Jobs: Similarities and Differences by Age and Across Time

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    Whether and to what extent men and women hold differing preferences for particular job attributes remains the subject of debate, with a sizable number of empirical studies producing conflicting results. These conflicts may have temporal sources—historical changes in men\u27s and women\u27s preferences for particular job attributes, as well as changes in preferences that commonly occur over individuals\u27 life cycle. Most previous research has neglected the effects of time on gender differences. Using data from national surveys of workers over a 22-year period, this study focuses explicitly on changes by age over time in men\u27s and women\u27s preferences for five key attributes of jobs—short hours, high income, meaningful work, chances for promotion, and job security. The results suggest that gender differences in preferences have been both stable and limited, although there is some evidence that the gender gap in preferences has actually widened among younger workers in recent years

    Flight investigation of cockpit-displayed traffic information utilizing coded symbology in an advanced operational environment

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    Traffic symbology was encoded to provide additional information concerning the traffic, which was displayed on the pilot's electronic horizontal situation indicators (EHSI). A research airplane representing an advanced operational environment was used to assess the benefit of coded traffic symbology in a realistic work-load environment. Traffic scenarios, involving both conflict-free and conflict situations, were employed. Subjective pilot commentary was obtained through the use of a questionnaire and extensive pilot debriefings. These results grouped conveniently under two categories: display factors and task performance. A major item under the display factor category was the problem of display clutter. The primary contributors to clutter were the use of large map-scale factors, the use of traffic data blocks, and the presentation of more than a few airplanes. In terms of task performance, the cockpit-displayed traffic information was found to provide excellent overall situation awareness. Additionally, mile separation prescribed during these tests

    Towards Load-Deformation Models for Screw-Fastened Cold-Formed Steel-to-Steel Shear Connections

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    This paper summarizes results from an experimental program considering single-fastened cold-formed steel-to-steel shear connections. Fastener motion (displacement and tilting angle) and bearing deformation occurring on the connecting members at the fastener location were captured using an automated, optical non-contact measurement procedure. The results are used to relate cold-formed steel-to-steel shear connection load-deformation response to tilting and bearing response. A general steel-to-steel single shear fastener load-deformation equation is also proposed and demonstrated

    Characterizing the Load Deformation Behaviour of Steel Deck Diaphragms

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    Lateral loads flow through a building’s horizontal roof and floor diaphragms before being transferred to the vertical lateral force resisting system (e.g. braced frames, moment frames or shear walls). These diaphragms are therefore a critical structural component in the resistance of lateral loads. A review of the literature shows that a large number of experimental programs have been performed to obtain the in-plane load-deformation behavior of steel deck and concrete on steel deck diaphragms. The tested diaphragm behavior was found to be dependent on a set of factors including loading protocol, fastener type, fastener size and spacing, and more. There does not currently exist a single, unifying review of these diaphragm tests and their relevant results. A research program is being conducted to collect and consolidate the available literature about tested steel deck diaphragms and their results. A database has been created that includes over 450 tested specimens with more than 130 cyclic tests. In addition, an effort is made to characterize diaphragms’ load-deformation response as grouped by sidelap and support fastener type. The test programs and results collected into this database as well as the characterization of diaphragm behavior are discussed in this paper

    Land Sold from Rev. Simon van Velzen to Dr. G. C. de Moen

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    Rev. Simon van Velzen sold a piece of propety in Gramsberen, Province of Overijssel to Dr. G. C. de Moen, a doctor in Leiden for 2,390.50 guilders. Van Velzen had inherited a share in the propety from his deceased wife, a sister of de Moen and Mrs. Christina Van Raalte.https://digitalcommons.hope.edu/vrp_1840s/1002/thumbnail.jp

    Physician network position and patient outcomes following implantable cardioverter defibrillator therapy

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/150523/1/hesr13151.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/150523/2/hesr13151_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/150523/3/hesr13151-sup-0001-AuthorMatrix.pd

    The Lyngen Gabbro: the lower crust of an Ordovician Incipient-Arc

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    We present evidence for the origin of the Lyngen Gabbro of the Ordovician Lyngen Magmatic Complex in Troms, Northern Norway. The two magmatic suites of the Lyngen Gabbro strike parallel NNE-SSW, and have distinct magmatic signatures. We define these signatures by using major and trace-element analyses together with selected major- and trace-element mineral analyses and 143Nd/144Nd-isotope whole-rock analyses of gabbroic to tonalitic plutonic rocks from seven detailed cross-sections from this large gabbro-complex. The Western suite of the Lyngen Gabbro precipitated from magma that may have been derived from the same system as the associated volcanic rocks. The gabbros have high An-content (An>90) of their plagioclases relative to co-existing mafic minerals. Together with somewhat high ɛNd(t) values (+6), this implies that the parental magmas were hydrous tholeiites similar to those found in back arc basins today. The Eastern suite, on the other hand, consist of cumulates that were precipitated from melts resembling those of ultra-depleted high-Ca boninitic magmas found in fore-arcs. Extremely high-An plagioclases (An>95) co-exist with evolved mafic minerals and oxides, and the ɛNd(t) values are lower (+4) than in the Western suite. The Eastern suite has no volcanic counterpart, but dikes intersecting the suites have compositions that possibly represent its parental magma. The oceanic Rypdalen Shear Zone generally separates the two suites in the north, but several non-tectonic transitions from boninitic to tholeiitic signatures southwards advocate that the magmatism happened concurrently. The magmatic proximity between the suites, the hydrous magmatism and the absence of a silicic or calc-alkaline mature arc section, suggests that the Lyngen Gabbro formed in the Iapetus Ocean under conditions presently found in incipient arcs later emplaced as outer arc highs
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