197,418 research outputs found
Running performance of an aerodynamic journal bearing with squeeze film effect
No full textResults of theoretical and experimental studies concerning the performance of an aerodynamic journal bearing which running is assisted by squeeze film ultrasonic levitation (SFUL) are presented in this paper. The SFUL mechanism not only can separate journal from the bearing at the start and stop phases of operation but also can significantly contribute to the dynamic stability of the bearing when it runs at speed. Computer calculations and validating experimental testing of a prototype device were carried out. It was found that that SFUL mechanism, when combined with aerodynamic lift, extends the threshold speed of bearing’s instability by almost four times comparing to that of a bearing operating without SFUL. Typically, the bearing running without SFUL became unstable at the speed of 300 rpm while with the SFUL the speed at which instability became apparent was 10,000 rpm (calculated result) or 13,200 (experimental result)
Peculiarities associated with testing polyetheretherketone (PEEK) in a model rolling contact
No full textCommonly used four-ball testing configuration when used to investigate rolling contact behavior of polyetheretherketone (PEEK) produced some unexpected peculiarities, namely direct contact between ceramic balls. Direct contact between lower three balls is normally not expected to take place when elastic materials (ferrous or ceramics) are tested. However, due to the viscoelastic nature of PEEK surface damage of the ceramic balls were observed leading to the production of wear debris which in turn facilitated premature failure of PEEK components of the assembly. It is postulated that caution is required when using the four-ball testing configuration to assess rolling contact performance of viscoelastic materials, such as engineering polymers.Gdansk University of Technology, Gdansk, Poland(Grant DS-2012)
Behavioral genetic study of time perspectives
No full textThe dataset contains the data collected within the GALTON study, which was a part of a research program entitled "In search for time perspective origins: Genetic and environmental bases of subjective attitudes towards time" funded by National Science Centre, Poland (2014/13/D/HS6/02951), awarded to Maciej Stolarski. Participants were 411 Polish same-sex twin pairs, reared together. The participants completed a set of measures including a 64-item version of the Zimbardo Time Perspective Inventory (ZTPI), the 50 item set of International Personality Item Pool Big Five Factor Markers (IPIP-BFM-50) questionnaire (Goldberg, 1992) in the Polish adaptation by Strus et al. (2017). Zygosity was diagnosed by the Polish version of the Questionnaire of Twins Physical Resemblance (QTPR; Oniszczenko & Rogucka, 1996). The predictive accuracy of the scale reaches 93.9% (96.2% for monozygotic and 90% for dizygotic pairs). In the case of a discrepancy between QTPR-based and self-reported zygosity, couples were excluded from the analyses. The ultimate sample comprised 393 same-sex twin pairs, reared together. Among them 135 were classified as monozygotic (MZ) and 258 as dizygotic (DZ) twins. MZ twins (88 females, 47 males) were aged between 15 and 48 years (M=24, SD=7.1) and DZ (189 females and 69 males) were between 15 and 57 years (M=21.9, SD=5.6).THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV
Optimization of agricultural practices for crambe in Europe
No full textCrambe (Crambe abyssinica Hochst R.E. Fries) has recently attracted a renewed interest by the bio-based industry due to its high seed oil content (up to 57%), particularly erucic acid (up to 65% of total fatty acids), short growing cycle, and high drought tolerance. A field trial was conducted during four consecutive growing seasons (2016−19) in Greece, Poland, and Italy. The commercial crambe variety (Galactica) was sown in early, intermediate, and late sowing dates in spring at two seeding rates (LD: 100 seeds m−2, and HD: 200 seeds m−2) in a factorial design at each test location. Mean crambe seed yields exceeded 1.5 Mg DM ha-1 across all years and locations. Italy and Greece were the most productive sites, with average seed yields of 2.11 Mg DM ha-1 and 1.97 Mg DM ha-1, respectively. Oil yield, which was only determined in Italy and Poland, was about 30% greater in the southern environment (Italy). Nevertheless, 1000-seed weight was greater in Poland (6.49 g) than Italy (6.12 g), revealing that lower temperatures during seed filling resulted in heavier seeds. In conclusion, sowing date played a key role in crambe productivity, with the earliest sowing resulting in highest yields across all locations
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States" By M. Carey.
No full text"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States: containing bried sketches of the moral and political character of those states.
By M. Carey, member of the American philosophical, and of the American Antiquarian Society, and author of The Olive Branch, Cindiciae Hibernicae, essays on banking, on political economy, and on internal improvement.
To which are now added the English editor's comments on the subject; together with Important Advice to Emigrants, and Cautions Against Impositions Practiced in the Outports
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Running characteristics of aerodynamic bearing with self-lifting capability at low rotational speed
No full textThis article has been made available through the Brunel Open Access Publishing Fund - Copyright @ 2011 Tadeusz Adam Stolarski.An aerodynamic journal bearing that is capable of self-generating squeeze-film pressure is presented and its dynamic characteristics investigated numerically and experimentally. A numerical method based on a time-marching static model was applied to assess the orbit trajectory path of the rotor upon a perturbation. Experimental results were obtained to validate the effect of the self-generated squeeze-film pressure on the stability of the rotor. Analyzing the Fast Fourier Transform (FFT) responses of the rotor orbits enabled identification of self-excited whirling instabilities. Both numerical and experimental results showed that increasing the squeeze-film effect of the bearing could raise the threshold speed of instability
Dr. Glendon Swarthout
No full textHosted by Roger M. Busfield, MSU Assistant Professor of Speech and Theater, Meet the Author is designed to introduce a general audience to a contemporary author and their work through in-depth interviews. This episode features a conversation between Dr. Glendon Swarthout, prolific author and English professor at MSU, and assistant professors Sam S. Baskett and Theodore B. Strandness
Sowing dates effect on Camelina growth in different EU climatic zones
No full textCamelina sativa (L.) Crantz, is an annual plant belonging to the Brassicaceae family, as rapeseed. It is native to central Europe where it was widely cultivated until the 1940s. However, only recently it gained the interest of the energy and bio-based industries as a low-cost non-food crop for aviation biofuel production and the oleochemical industry, due to its high oil content (up to 40%) and suitable oil profile. Field trials are performed at different locations in Europe, to study the effect of sowing dates on camelina seed and oil yields, in three different environments, the South (Greece) and North Mediterranean (Italy) climatic zones as well as the Continental zone (Poland). The activity was organized in two separate experiments: autumn sowing and spring sowing with two camelina varieties: Midas, a spring variety supplied by Linnaeus Plant Science (Canada), and Luna, a commercial winter variety from Poland. Total biomass ranged between 2.8 – 9.8 Mg DM ha-1, depending on the site and sowing seasons, with the highest figures in Italy and the lowest in Greece. Seed yields ranged from 0.56 – 2.11 Mg DM ha-1, depending on the site and sowing seasons, with the highest figures in the mild Mediterranean environments. Likewise, oil content ranged between 36.50 – 40.55%. Winter camelina reached almost double the seed yield compared to the spring crop for the same spring variety, Midas. Autumn sowing was found more productive than spring sowing for seed yields and oil content both in Greece and Italy, while in Poland, only real winter camelina varieties survive winter
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