257 research outputs found
6-Hydroxy-5,7,8-trimethylchroman-2-one
The title compound, C12H14O3, consists of a chromanone unit with an –OH substituent at the 4-position and methyl substituents on the remaining C atoms of the aromatic ring. The fused pyranone ring adopts a distorted envelope conformation with the methylene group adjacent to the carbonyl carbon as the flap atom. The crystal structure is stabilized by classical O—H⋯O hydrogen bonds and weak C—H⋯O and C—H⋯π interactions, generating a three-dimensional network
Solid State Systems for Electron Electric Dipole Moment and other Fundamental Measurements
In 1968, F.L. Shapiro published the suggestion that one could search for an
electron EDM by applying a strong electric field to a substance that has an
unpaired electron spin; at low temperature, the EDM interaction would lead to a
net sample magnetization that can be detected with a SQUID magnetometer. One
experimental EDM search based on this technique was published, and for a number
of reasons including high sample conductivity, high operating temperature, and
limited SQUID technology, the result was not particularly sensitive compared to
other experiments in the late 1970's.
Advances in SQUID and conventional magnetometery had led us to reconsider
this type of experiment, which can be extended to searches and tests other than
EDMs (e.g., test of Lorentz invariance). In addition, the complementary
measurement of an EDM-induced sample electric polarization due to application
of a magnetic field to a paramagnetic sample might be effective using modern
ultrasensitive charge measurement techniques. A possible paramagnetic material
is Gd-substituted YIG which has very low conductivity and a net enhancement
(atomic enhancement times crystal screening) of order unity. Use of a
reasonable volume (100's of cc) sample of this material at 50 mK and 10 kV/cm
might yield an electron EDM sensitivity of e cm or better, a factor
of improvement over current experimental limits.Comment: 6 pages. Prepared for ITAMP workshop on fundamental physics that was
to be held Sept 20-22 2001 in Cambride, MA, but was canceled due to terrorist
attack on U.S New version incorporates a number of small changes, most
notably the scaling of the sensitivity of the Faraday magnetometer with
linewidth is now treated in a saner fashion. The possibility of operating at
an even lower temperarture, say 10 microkelvin, is also discusse
Gel actuators based on polymeric radicals
Low-voltage electrochemical actuation of radical polymer gels has been demonstrated in an organic electrolyte. Polymer gels were prepared by post-modification of active-ester precursor gels with an amine-functionalised radical. A combination of few-layer graphene and multiwall carbon nanotubes gave high conductivity and improved actuation in the gels, with 32% linear actuation. The actuator system showed good stability over at least 10 cycles, showing its promise. The cycle time was several hours due to mass-transport limited transport of ions and solvent into the device
N-(1-Acryloyl-2,2,6,6-tetramethylpiperidin-4-yl)acrylamide
The title compound, C15H24N2O2, crystallizes with two unique molecules, (I) and (II), in the asymmetric unit, differing in the orientation of the acryloyl units with respect to the piperidine rings. The acrylamide units are essentially planar in both molecules (r.m.s. deviations = 0.042 and 0.024 Å, respectively), as are the C3N chains of the acryloyl units. The carbonyl O atoms of the acryloyl systems lie significantly out of these planes, viz. by −0.171 (9) Å for molecule (I) and by 0.33 (1) Å for molecule (II). The acrylamide and acryloyl planes are inclined at 68.7 (4)° and 59.8 (3)° in the two molecules. The piperidine rings each adopt twist boat conformations. In the crystal, strong N—H⋯O hydrogen bonds link the molecules into zigzag C(4) chains along b. Additional C—H⋯O contacts result in the formation of stacks along a
Predicting swimming performance using state anxiety
Competitive state anxiety is a common response to stressful competitive sports situations that could affect athletic performance. The effects of state anxiety on swimming performance need further inquiry. The aim of the study was to determine the component of state anxiety that best predicts swimming performance. A quantitative, cross-sectional study design that made use of the Competitive State Anxiety Inventory-2 to measure precompetitive state anxiety was used. A total of 61 male high school swimmers whose age ranged between 14 and 19 years (M = 16.16, standard deviation = 1.66 years) completed the Competitive State Anxiety Inventory-2 1 hr before competing in a 50-m individual swimming event. Performance was evaluated using finishing position. Due to the relatively short duration of the 50-m event, the available literature would suggest that Somatic Anxiety would have a greater effect on Performance - there is not enough time to allow cognitive anxiety to have a detrimental impact on performance. Thus, it was hypothesized that somatic rather than cognitive anxiety will best predict swimming performance. It emerged that both cognitive (b =.787; p <.001) and somatic anxieties (b =.840; p <.001) can independently predict swimming performance. However, when both cognitive and somatic anxieties were regressed onto swimming performance, somatic anxiety partially dominated cognitive anxiety (b =.626; p <.001) and became the significant predictor of swimming performance. It is recommended that swimmers and swimming coaches make use of specific intervention strategies that eradicate the detrimental effects of somatic anxiety immediately before competition.IS
The Golden Meteorite Fall: Fireball Trajectory, Orbit and Meteorite Characterization
The Golden (British Columbia, Canada) meteorite fall occurred on Oct 4, 2021
at 0534 UT with the first recovered fragment (1.3 kg) landing on an occupied
bed. The meteorite is an unbrecciated, low-shock (S2) ordinary chondrite of
intermediate composition, typed as an L/LL5. From noble gas measurements the
cosmic ray exposure age is 25 Ma while gas retention ages are all >2 Ga.
Short-lived radionuclides and noble gas measurements of the pre-atmospheric
size overlap with estimates from infrasound and lightcurve modelling producing
a preferred pre-atmospheric mass of 70-200 kg. The orbit of Golden has a high
inclination (23.5 degs) and is consistent with delivery from the inner main
belt. The highest probability (60%) of an origin is from the Hungaria group. We
propose that Golden may originate among the background S-type asteroids found
interspersed in the Hungaria region. The current collection of 18 L and LL
chondrite orbits shows a strong preference for origins in the inner main belt,
suggesting multiple parent bodies may be required to explain the diversity in
CRE ages and shock states.Comment: 92 Pages, 20 Tables, 21 Figures, plus 3 appendices, accepted in
Meteoritics and Planetary Science Oct 26 202
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