25,616 research outputs found
Latch mechanism
Rachet device transfers loads imposed on latch to support structure before latch springs resist loads, positively locks two pivoted structures on contact, and carries loads in all directions
Latching device
A latching device is suited for use in establishing a substantially motionless connection between a stationary receiver and a movable latching mechanism. The latching mechanism includes a pivotally supported restraining hook continuously urged into a capturing relationship with the receiver, characterized by a spring-biased pawl having a plurality of aligned teeth. The teeth are seated in the surface of the throat of the hook and positionable into restraining engagement with a rigid restraining shoulder projected from the receiver
Quark mixing and CP violation - the CKM matrix
I present the status of the elements and parameters of the
Cabibbo-Kobayashi-Maskawa (CKM) matrix and summarise the related theoretical
progress since "Lepton-Photon 2003". One finds |V_{us}| = 0.2227 +/- 0.0017
from K and tau decays and |V_{cb}| = (41.6 +/- 0.5) * 10^{-3} from inclusive
semileptonic B decays. The unitarity triangle can now be determined from
tree-level quantities alone and the result agrees well with the global fit
including flavour-changing neutral current (FCNC) processes, which are
sensitive to new physics. From the global fit one finds the three CKM angles
theta_{12}=12.9 +/- 0.1 degrees, theta_{23}= 2.38 +/- 0.03 degrees and
theta_{13}= 0.223 +/- 0.007 degrees in the standard PDG convention. The CP
phase equals delta_{13} = gamma = (58.8 +5.3/-5.8) degrees at 1 sigma CL and
gamma=(58.8 +11.2/-15.4) degrees at 2 sigma CL. A major progress are first
results from fully unquenched lattice QCD computations for the hadronic
quantities entering the UT fit. I further present the calculation of three-loop
QCD corrections to the charm contribution in K+ -> pi+ nu nu-bar decays, which
removes the last relevant theoretical uncertainty from the K -> pi nu nu-bar
system. Finally I discuss mixing-induced CP asymmetries in b -> s q-bar q
penguin decays, whose naive average is below its Standard Model value by 3
sigma.Comment: 14 pages, 12 figures, plenary talk at "Lepton-Photon 2005
The 1723 AD violent Strombolian and phreatomagatic eruption at Irazu volcano (Costa Rica)
The largest of the recorded historic eruptions at IrazĂș volcano began on February 16, 1723 and lasted
until at least December 11. We here critically examine deposits of this eruption exposed on the summit of IrazĂș. Our
reconstruction of the eruption is based on the unique chronicle of the Spanish governor Diego de la Haya. The eruption
began with a < 10 cm thick surge deposit of phreatic origin showing block sag structures. The deposit is overlain by
6 m-thick coarse-grained basaltic andesitic non-graded juvenile fallout tephra consisting of highly vesicular (22-59
vol.%) bombs and lapilli with minor hydrothermally altered lapilli (1-7 vol.%) and rare light colored andesitic vesicular
lapilli (< 1%). These fallout deposits are interpreted as strombolian, possible generated during a short-lived scoria cone
at the end of February 1723, dominate volumetrically in the proximal facies. Overlying <1.2 m thick phreatomagmatic
deposits of fi nely laminated lapilli-bearing gray ash (fallout and surge deposits) some with contorted bedding and sag
structures, are in turn overlain by a 1.2 m thick bed of ash matrix-rich bomb/block deposit. The 1723 eruption was
accompanied by shallow volcano-tectonic earthquakes (Modifi ed Mercalli scale Intensity MMI VI-VII, magnitude ML
~5.5) that possibly facilitated magma/water interaction. Phenocrysts in the basaltic andesite (~53-55 wt.% SiO2) bombs
comprise plagioclase (6.1-21.6 vol.%, An52-35), clinopyroxene (2.5-10 vol.%), orthopyroxene (0.7-2 vol.%), olivine
(0.1-2.2 vol.%; Fo76-88) and Fe/Ti-oxides (0.1-1%), in a groundmass (66.5-90.3 vol. %), dominated by plagioclase
(An69-54), clinopyroxene and opaques in brown and black glass with the same range of chemical composition (SiO2=
57-64 wt.%). Rare white pumiceous lapilli in the scoria deposits are high-K, hornblende andesite (SiO2: 58-60 wt.%),
geochemically unrelated to the scoria deposits. Thus, two different magmas co-existing in the magma chamber were
mingled shortly before, and during, the eruption, suggesting that the eruption was triggered by magma mingling between
hornblende andesite and basaltic andesite magma
Apollo 12 Voice Transcript Pertaining to the Geology of the Landing Site, Volume 2
An edited record of the conversions between the Apollo 12 astronauts and mission control pertaining to the geology of the landing site, is presented. All discussions and observations documenting the lunar landscape, its geologic characteristics, the rocks and soils collected and the lunar surface photographic record are included along with supplementary remarks essential to the continuity of events during the mission
The Role of Permanent Income and Demographics in Black/White Differences in Wealth
We explore the extent to which the huge race gap in wealth can be explained with properly constructed income and demographic variables. In some instances we explain the entire wealth gap with income and demographics provided that we estimate the wealth model on a sample of whites. However, we typically explain a much smaller fraction when we estimate the wealth model on a black sample. Using sibling comparisons to control for intergenerational transfers and the effects of adverse history, we find that differences in income and demographics are not likely to account for the lower explanatory power of the black wealth models. Our analysis of growth models of wealth suggests that differences in savings behavior and/or rates of return play an important role.Black-White Wealth Gap, Siblings, Savings
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