2,924 research outputs found
Transonic divider for gas chromatograph effluents
Transonic effluent divider system was developed which permits varying mass input of gas chromatographic effluent into mass spectrometer without affecting performance of gas chromatograph. Mechanisms of operation are described
Compact rotating cup anemometer
Compact, collapsible rotating cup anemometer is used in remote locations where portability and durability are factors in the choice of equipment. This lightweight instrument has a low wind-velocity threshold, is capable of withstanding large mechanical shocks while in its stowed configuration, and has fast response to wind fluctuations
Evaluation of a load cell model for dynamic calibration of the rotor systems research aircraft
The Rotor Systems Research Aircraft uses load cells to isolate the rotor/transmission system from the fuselage. An analytical model of the relationship between applied rotor loads and the resulting load cell measurements is derived by applying a force-and-moment balance to the isolated rotor/transmission system. The model is then used to estimate the applied loads from measured load cell data, as obtained from a ground-based shake test. Using nominal design values for the parameters, the estimation errors, for the case of lateral forcing, were shown to be on the order of the sensor measurement noise in all but the roll axis. An unmodeled external load appears to be the source of the error in this axis
The Strength of Internet Ties
Presents findings from a survey that examines how Americans use the Internet and email to support and expand their social networks and access resources for assistance in making major life decisions
Palynological analysis of Upper Ordovician to Lower Silurian sediments from the Diyarbakir Basin, southeastern Turkey
This paper reports on a palynological analysis of 41 core and 21 cutting samples from a well drilled through an Upper Ordovician–Lower Silurian sequence, belonging to the Bedinan and Dadas formations, of the Diyarbakır Basin of southeastern Turkey. The samples yield abundant and well-preserved marine palynomorphs (acritarchs, chitinozoans and scolecodonts) although non-marine palynomorphs (spores/cryptospores) are extremely rare or absent. The Upper Ordovician sediments of the Bedinan Formation have low organic content but contain abundant palynomorphs whereas the Lower Silurian sediments of the Dadas Formation have high organic content, dominated by amorphous organic matter, with relatively rare palynomorphs. Three chitinozoan assemblages are identified and attributed a late Katian (merga Biozone), Hirnantian (moussegoudaensis Biozone) and Llandovery (?alargada Biozone) age. Two acritarch assemblages are identified and attributed a Katian–Hirnantian and Llandovery (Aeronian–Telychian) age. The chitinozoan and acritarch age determinations are compatible and suggest that the Bedinan Formation is of Katian–Hirnantian age and is separated by an unconformity from the Dadas Formation that is of Llandovery (Aeronian–Telychian) age. These findings confirm the presence of an unconformity at the Ordovician–Silurian transition in the southeastern Turkey. Palynofacies analysis suggests that the Bedinan Formation accumulated on an offshore shelf that was initially well oxygenated but became increasingly anoxic, whereas the Dadas Formation accumulated in an offshore basin that was anoxic. Palynomorph assemblages recorded in the Bedinan and Dadas formations indicate northern Gondwana affinity
The imaging spectrometer approach
Two important sensor design drivers are the requirement for spatial registration of the spectral components and the implementation of the advanced multispectral capability, including spectral band width, number of bands and programmability. The dispersive approach, fundamental to the imaging spectrometer concept, achieves these capabilities by utilizing a spectrometer to disperse the spectral content while preserving the spatial identity of the information in the cross-track direction. Area array detectors in the spectrometer focal plane detect and store the spatial and multispectral content for each line of the image. The choice of spectral bands, image IFOV and swath width is implemented by programmed readout of the focal plane. These choices in conjunction with data compression are used to match the output data rate with the telemetry link capability. Progress in the key technologies of optics, focal plane detector arrays, onboard processing, and focal plane cooling supports the viability of the imaging spectrometer approach
An exploration of concepts of community through a case study of UK university web production
The paper explores the inter-relation and differences between the concepts of occupational community, community of practice, online community and social network. It uses as a case study illustration the domain of UK university web site production and specifically a listserv for those involved in it. Different latent occupational communities are explored, and the potential for the listserv to help realize these as an active sense of community is considered. The listserv is not (for most participants) a tight knit community of practice, indeed it fails many criteria for an online community. It is perhaps best conceived as a loose knit network of practice, valued for information, implicit support and for the maintenance of weak ties. Through the analysis the case for using strict definitions of the theoretical concepts is made
An introduction to spacecraft thermal control
External and internal passive and active methods for spacecraft thermal control - material insulation and structural propertie
Communicating With the Elderly: Gender and Contact Differences in Prototypes, Hesitation Phenomena, Proxemics, and Interaction Evaluations.
The purpose of the present dissertation was to examine some of the perceptions younger adults have about the elderly, communication behaviors during a cross-generational interaction, and evaluations of the interaction. The present investigation used an experimental design that included the following two independent variables: (1) gender and (2) amount of interaction (or contact) a younger adult has with elderly people. Subjects were categorized into high, medium, or low contact groups based on self-reports. The study consisted of an initial survey, an experiment (younger subjects interviewed by an elderly confederate), and a postinteraction survey. The gender and contact factors were investigated in relation to the following dependent variables: (1) a self-generated elderly prototype; (2) hesitation phenomena, including ah, non-ah, and silent pauses during the interage interview; (3) proxemics during the interage interview; and (4) interaction evaluations following the interview. Results indicated that there were significant gender differences for the complexity and redundancy of self-generated elderly prototypes. Females generated more complex elderly prototypes than males. A multivariate analysis of variance evidenced significant gender differences in hesitation phenomena; females exhibited fewer hesitations than males. There were significant univariate gender differences for ah pauses as well, indicating females used fewer ah pauses. There was no support for gender effects on proxemics or interaction evaluations. No significant results were found due to differences in amount of contact with elderly individuals. Conclusions for the present study are discussed in regard to prototypes, verbal fluency, nonverbal expectancy violations, kinkeeping, and younger adults\u27 general perceptions of elderly and judgements of elderly conversational partners
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