925 research outputs found
Structural modeling of aircraft tires
A theoretical and experimental investigation of the feasibility of determining the mechanical properties of aircraft tires from small-scale model tires was accomplished. The theoretical results indicate that the macroscopic static and dynamic mechanical properties of aircraft tires can be accurately determined from the scale model tires although the microscopic and thermal properties of aircraft tires can not. The experimental investigation was conducted on a scale model of a 40 x 12, 14 ply rated, type 7 aircraft tire with a scaling factor of 8.65. The experimental results indicate that the scale model tire exhibited the same static mechanical properties as the prototype tire when compared on a dimensionless basis. The structural modeling concept discussed in this report is believed to be exact for mechanical properties of aircraft tires under static, rolling, and transient conditions
High-Energy Gamma-Ray Observations of Two Young, Energetic Radio Pulsars
We present results of Compton Gamma-Ray Observatory EGRET observations of the
unidentified high-energy gamma-ray sources 2EG J1049-5847 (GEV J1047-5840, 3EG
J1048-5840) and 2EG J1103-6106 (3EG J1102-6103). These sources are spatially
coincident with the young, energetic radio pulsars PSRs B1046-58 and
J1105-6107, respectively. We find evidence for an association between PSR
B1046-58 and 2EG J1049-5847. The gamma-ray pulse profile, obtained by folding
time-tagged photons having energies above 400 MeV using contemporaneous radio
ephemerides, has probability of arising by chance of 1.2E-4 according to the
binning-independent H-test. A spatial analysis of the on-pulse photons reveals
a point source of equivalent significance 10.2 sigma. Off-pulse, the
significance drops to 5.8 sigma. Archival ASCA data show that the only hard
X-ray point source in the 95% confidence error box of the gamma-ray source is
spatially coincident with the pulsar within the 1' uncertainty (Pivovaroff,
Kaspi & Gotthelf 1999). The double peaked gamma-ray pulse morphology and
leading radio pulse are similar to those seen for other gamma-ray pulsars and
are well-explained in models in which the gamma-ray emission is produced in
charge-depleted gaps in the outer magnetosphere. The inferred pulsed gamma-ray
flux above 400 MeV, (2.5 +/- 0.6) x 10E-10 erg/cm^2/s, represents 0.011 +/-
0.003 of the pulsar's spin-down luminosity, for a distance of 3 kpc and 1 sr
beaming. For PSR J1105-6107, light curves obtained by folding EGRET photons
using contemporaneous radio ephemerides show no significant features. We
conclude that this pulsar converts less than 0.014 of its spin-down luminosity
into E > 100 MeV gamma-rays beaming in our direction (99% confidence), assuming
a distance of 7 kpc, 1 sr beaming and a duty cycle of 0.5.Comment: Accepted for publication in the Astrophysical Journa
Elgin on understanding:How does it involve know-how, endorsement and factivity?
In Chapter 3 of True Enough, Elgin (2017) outlines her view of objectual understanding, focusing largely on its non-factive nature and the extent to which a certain kind of know-how is required for the âgraspingâ component of understanding. I will explore four central issues that feature in this chapter, concentrating on (1) the role of know-how, (2) the concept of endorsement, (3) Elginâs critique of the factivity constraint on understanding, and (4) how we might use aspects of Elginâs framework to inform related debates on the norm of assertion
Operation and performance of the new Fermilab Booster H- injection system
The operation and performance of the new, 15 Hz, H{sup -} charge exchange injection system for the FNAL Booster is described. The new system installed in 2006 was necessary to allow injection into the Booster at up to 15 Hz. It was built using radiation hardened materials which will allow the Booster to reliably meet the high intensity and repetition rate requirements of the Fermilab's HEP program. The new design uses three orbit bump magnets (Orbumps) rather than the usual four and permits injection into the Booster without a septum magnet. Injection beam line modification and compensation for the quadrupole gradients of the Orbump magnets is discussed
Defining appropriateness in coach-athlete sexual relationships: The voice of coaches
The sporting culture, with omnipotent coaches, fierce competition for recognition and funding, and âwin at all costâ ethos, creates an environment conducive to sexual exploitation of athletes. Recent increased public awareness and the development of child protection policies in sport have led to the questioning of previously accepted coach-athlete relationships. This study is an exploratory investigation into male swimming coachesâ perceptions of appropriateness of coach-athlete sexual relationships. Sexual relationships with athletes under the age of 16 were unanimously considered totally inappropriate. With regard to sexual relationships with athletes above the age of consent for heterosexual sex, opinions ranged from âtotally inappropriateâ to âitâs a question of civil liberties.â These results are discussed in relation to how coaches have adapted their own behaviours in the face of public scrutiny but are still reluctant to restrict the rights of their fellow coaches
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A Gpr120-selective agonist improves insulin resistance and chronic inflammation in obese mice.
It is well known that the Ï-3 fatty acids (Ï-3-FAs; also known as n-3 fatty acids) can exert potent anti-inflammatory effects. Commonly consumed as fish products, dietary supplements and pharmaceuticals, Ï-3-FAs have a number of health benefits ascribed to them, including reduced plasma triglyceride levels, amelioration of atherosclerosis and increased insulin sensitivity. We reported that Gpr120 is the functional receptor for these fatty acids and that Ï-3-FAs produce robust anti-inflammatory, insulin-sensitizing effects, both in vivo and in vitro, in a Gpr120-dependent manner. Indeed, genetic variants that predispose to obesity and diabetes have been described in the gene encoding GPR120 in humans (FFAR4). However, the amount of fish oils that would have to be consumed to sustain chronic agonism of Gpr120 is too high to be practical, and, thus, a high-affinity small-molecule Gpr120 agonist would be of potential clinical benefit. Accordingly, Gpr120 is a widely studied drug discovery target within the pharmaceutical industry. Gpr40 is another lipid-sensing G protein-coupled receptor, and it has been difficult to identify compounds with a high degree of selectivity for Gpr120 over Gpr40 (ref. 11). Here we report that a selective high-affinity, orally available, small-molecule Gpr120 agonist (cpdA) exerts potent anti-inflammatory effects on macrophages in vitro and in obese mice in vivo. Gpr120 agonist treatment of high-fat diet-fed obese mice causes improved glucose tolerance, decreased hyperinsulinemia, increased insulin sensitivity and decreased hepatic steatosis. This suggests that Gpr120 agonists could become new insulin-sensitizing drugs for the treatment of type 2 diabetes and other human insulin-resistant states in the future
System support software for the Space Ultrareliable Modular Computer (SUMC)
The highly transportable programming system designed and implemented to support the development of software for the Space Ultrareliable Modular Computer (SUMC) is described. The SUMC system support software consists of program modules called processors. The initial set of processors consists of the supervisor, the general purpose assembler for SUMC instruction and microcode input, linkage editors, an instruction level simulator, a microcode grid print processor, and user oriented utility programs. A FORTRAN 4 compiler is undergoing development. The design facilitates the addition of new processors with a minimum effort and provides the user quasi host independence on the ground based operational software development computer. Additional capability is provided to accommodate variations in the SUMC architecture without consequent major modifications in the initial processors
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Design and Fabrication of a Multi-Element Corrector Magnet for the Fermilab Booster
A new package of six corrector elements has been designed to better control the beam position, tune, and chromaticity in the Fermilab Booster synchrotron. It incorporates both normal and skew orientations of dipole, quadrupole, and sextupole magnets. These new corrector magnets will be installed in the Fermilab Booster ring in place of old style corrector elements. A severe space restriction and rapid slew rate have posed special challenges. The magnet design, construction, and performance are presented
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