2,288 research outputs found
Identified kaon production in Ar+Sc collisions at SPS energies
NA61/SHINE is a fixed target experiment at the CERN Super Proton Synchrotron.
The main goals of the experiment are to discover the critical point of strongly
interacting matter and to study the properties of the onset of deconfinement.
In order to reach these goals, a study of hadron production properties is
performed in nucleus-nucleus, proton-proton and proton-nucleus interactions as
a function of collision energy and size of the colliding nuclei. In this talk,
the newest preliminary results on kaon spectra produced in Ar+Sc collisions at
three beam momenta (30A, 40A and 75A) will be shown. The distributions of
transverse mass and rapidity will be compared with results of NA61/SHINE (p+p,
Be+Be) and NA49 (Pb+Pb, C+C, Si+Si), as well as with available world data
News on strangeness production from NA61/SHINE
NA61/SHINE is a fixed target experiment at the CERN Super Proton Synchrotron.
The main goals of the experiment are to discover the critical point of strongly
interacting matter and to study the properties of the onset of deconfinement.
In order to reach these goals, a study of hadron production properties is
performed in nucleus-nucleus, proton-proton and proton-nucleus interactions as
a function of collision energy and size of the colliding nuclei. In this talk,
the new results on identified charged kaon production in the intermediate size
system (Ar+Sc and Be+Be) collisions at SPS beam momentum range (13A-150A GeV/c)
will be shown. Additionally, the new measurements of strange mesons (KS0),
resonances (K0*(892), Xi(1530) 0 and Xi0(1530)) and baryons (Xi-(1321),
Xi+(1321)) produced in p+p interactions are presented
Helicopter transmission research at NASA Lewis Research Center
A joint helicopter transmission research program between NASA Lewis Research Center and the U.S. Army Aviation Systems Command has existed since 1970. Program goals are to reduce weight and noise and to increase life and reliability. Reviewed are significant advances in technology for gears and transmissions and the experimental facilities at NASA Lewis for helicopter transmission testing are described. A description of each of the rigs is presented along with some significant results from the experiments
Tooth Contact Shift in Loaded Spiral Bevel Gears
An analytical method is presented to predict the shifts of the contact ellipses of spiral bevel gear teeth under load. The contact ellipse shift is the motion of the tooth contact position from the ideal pitch point to its location under load. The shifts are due to the elastic motions of the gear and pinion supporting shafts and bearings. The calculations include the elastic deflections of the gear shafts and the deflections of the four shaft bearings. The method assumes that the surface curvature of each tooth is constant near the unloaded pitch point. Results from these calculations will help designers reduce transmission weight without seriously reducing transmission performance
Effect of advanced component technology on helicopter transmissions
Experimental tests were performed on the NASA/Bell Helicopter Textron (BHT) 500 hp advanced technology transmission (ATT) at the NASA Lewis Research Center. The ATT was a retrofit of the OH-58C helicopter 236 kW (317 hp) main rotor transmission, upgraded to 373 kW (500 hp), with a design goal of retaining long life with a minimum increase in cost, weight, and size. Vibration, strain, efficiency, deflection, and temperature experiments were performed and the results were compared to previous experiments on the OH-58A, OH-58C, and UH-60A transmissions. The high-contact-ratio gears and the cantilevered-mounted, flexible ring gear of the ATT reduced vibration compared to that of the OH-58C. The ATT flexible ring gear improved planetary load sharing compared to that of the rigid ring gear of the UH-60A transmission. The ATT mechanical efficiency was lower than that of the OH-58A transmission, probably due to the high-contact-ratio planetary gears
An investigation of the nature and reactivity of the carbonaceous species deposited on mordenite by reaction with methanol
An investigation of the nature of the carbonaceous species deposited upon mordenite by reaction with methanol has been undertaken. The nature of the species has been shown to be a strong function of both temperature and time on stream. Upon reaction at 300 degrees C a range of alkyl and aromatic species, consistent with the development of an active hydrocarbon pool, are evident and time on stream studies have shown that these are developed within 5 min. Upon reaction at 500 degrees C, a narrower range of hydrogen deficient aromatic species is evident. Thermal volatilisation analysis (TVA), not previously applied to the study of coked zeolites, is shown to be complementary to the more commonly applied C analysis, C-13 MAS NMR and TGA techniques
Fast, scalable, Bayesian spike identification for multi-electrode arrays
We present an algorithm to identify individual neural spikes observed on
high-density multi-electrode arrays (MEAs). Our method can distinguish large
numbers of distinct neural units, even when spikes overlap, and accounts for
intrinsic variability of spikes from each unit. As MEAs grow larger, it is
important to find spike-identification methods that are scalable, that is, the
computational cost of spike fitting should scale well with the number of units
observed. Our algorithm accomplishes this goal, and is fast, because it
exploits the spatial locality of each unit and the basic biophysics of
extracellular signal propagation. Human intervention is minimized and
streamlined via a graphical interface. We illustrate our method on data from a
mammalian retina preparation and document its performance on simulated data
consisting of spikes added to experimentally measured background noise. The
algorithm is highly accurate
Transmission diagnostic research at NASA Lewis Research Center
The NASA Lewis Research Center and the U.S. Army Research Laboratory are involved in a joint research program to advance the technology of aerospace transmissions. Within the last six years, a transmission diagnostics research team was formed to address current and future technology barriers in transmission diagnostics. The diagnostics team conducted a survey to determine critical needs of the diagnostics community. Survey results indicated that experimental verification of gear and bearing fault detection methods and damage magnitude assessment were considered the two most critical research areas of a highly reliable health and usage monitoring system. A plan was implemented by the diagnostics team to address these key research areas, by in-house research and university grants. A variety of transmission fault detection methods were applied to experimentally obtained fatigue data. Failure modes of the fatigue tests include a variety of gear pitting failures, tooth wear, tooth fracture, and bearing spalling failures. Accomplishments to date include verification of several specific gear diagnostic methods, verification of a new pattern recognition method to determine failure, and development of a new method to model gear tooth damage. This paper presents the results of these accomplishments in transmission diagnostics research at NASA Lewis Research Center
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