2,481 research outputs found
The role of the Treaty of Waitangi in contemporary public law : does the Treaty have to be incorporated into municipal law to be of effect?
Recent work on Al-Cu-Mg based alloys with Cu:Mg atomic ratio close to unity is reviewed to clarify the mechanisms for age hardening. During the first stage of hardening a substantial exothermic heat evolution occurs whilst the microstructural change involves the formation of initially Cu-rich / Mg-rich clusters and later Cu-Mg co-clusters. The data show that the first stage of the age hardening is due to the formation of Cu-Mg co-clusters. The combined experimental methods show the second stage hardening is dominated by formation of S phase, which forms a dense precipitation at the peak hardness stage, whilst no significant amounts of other phases or zones are detected. S phase strengthens the alloy predominantly through the Orowan looping mechanism. These findings are incorporated into a multi-phase, multi-mechanism model for yield strength of Al-Cu-Mg based alloys
Hardening mechanism of commercially pure Mg processed by high pressure torsion at room temperature
Coarse-grained Mg in the as-cast condition and fine-grained Mg in the extruded condition were processed by high pressure torsion (HPT) at room temperature for up to 16 turns. Microstructure observation and texture analysis indicate that to fulfil the Von Mises criterion, the non-basal slip is activated in the as-cast Mg and tension twinning is activated in the as-extruded Mg. Although the deformation mechanism is different in the as-cast Mg and the as-extruded Mg during HPT, their hardening evolutions are similar, i.e. after 1/8 turn of HPT, microhardness of the as-cast Mg and the extruded Mg both show a significant increase and further HPT processing does not significantly further increase the microhardness. Texture strengthening can explain the rapid hardening. Hardness anisotropy and texture data results suggest that texture strengthening plays an important role for both types of samples. Texture strengthening weakens with decreasing grain size
Nicotinamide N-Methyl Transferase (NNMT): an emerging therapeutic target
Microbial Biotechnolog
Multiaxial Kitagawa analysis of A356-T6
Experimental Kitagawa analysis has been performed on A356-T6 containing
natural and artificial defects. Results are obtained with a load ratio of R =
-1 for three different loadings: tension, torsion and combined tension-torsion.
The critical defect size determined is 400 \pm 100 \mum in A356-T6 under
multiaxial loading. Below this value, the microstructure governs the endurance
limit mainly through Secondary Dendrite Arm Spacing (SDAS). Four theoretical
approaches are used to simulate the endurance limit characterized by a Kitagawa
relationship are compared: Murakami relationships [Y Murakami, Metal Fatigue:
Effects of Small Defects and Nonmetallic Inclusions, Elsevier, 2002.],
defect-crack equivalency via Linear Elastic Fracture Mechanics (LEFM), the
Critical Distance Method (CDM) proposed by Susmel and Taylor [L. Susmel, D.
Taylor. Eng. Fract. Mech. 75 (2008) 15.] and the gradient approach proposed by
Nadot [Y. Nadot, T. ~Billaudeau. Eng. Fract. Mech. 73 (2006) 1.]. It is shown
that the CDM and gradient methods are accurate; however fatigue data for three
loading conditions is necessary to allow accurate identification of an
endurance limit.Comment: 27 pages, 11 figure
p-wave phase shift and scattering length of Li
We have calculated the p-wave phase shifts and scattering length of Li.
For this we solve the partial wave Schr\"odinger equation and analyze the
validity of adopting the semiclassical solution to evaluate the constant
factors in the solution. Unlike in the wave case, the semiclassical
solution does not provide unique value of the constants. We suggest an
approximate analytic solution, which provides reliable results in special
cases. Further more, we also use the variable phase method to evaluate the
phase shifts. The p-wave scattering lengths of Cs and Cs are
calculated to validate the schemes followed. Based on our calculations, the
value of the wave scattering length of Li is .Comment: 10 figure
A New Model for Void Coalescence by Internal Necking
A micromechanical model for predicting the strain increment required to bring a damaged material element from the onset of void coalescence up to final fracture is developed based on simple kinematics arguments. This strain increment controls the unloading slope and the energy dissipated during the final step of material failure. Proper prediction of the final drop of the load carrying capacity is an important ingredient of any ductile fracture model, especially at high stress triaxiality. The model has been motivated and verified by comparison to a large set of finite element void cell calculations.
Extracting Br(omega->pi^+ pi^-) from the Time-like Pion Form-factor
We extract the G-parity-violating branching ratio Br(omega->pi^+ pi^-) from
the effective rho-omega mixing matrix element Pi_{rho omega}(s), determined
from e^+e^- -> pi^+ pi^- data. The omega->pi^+ pi^- partial width can be
determined either from the time-like pion form factor or through the constraint
that the mixed physical propagator D_{rho omega}^{mu nu}(s) possesses no poles.
The two procedures are inequivalent in practice, and we show why the first is
preferred, to find finally Br(omega->pi^+ pi^-) = 1.9 +/- 0.3%.Comment: 12 pages (published version
Gravitational-wave Detection With Matter-wave Interferometers Based On Standing Light Waves
We study the possibility of detecting gravitational-waves with matter-wave
interferometers, where atom beams are split, deflected and recombined totally
by standing light waves. Our calculation shows that the phase shift is
dominated by terms proportional to the time derivative of the gravitational
wave amplitude. Taking into account future improvements on current
technologies, it is promising to build a matter-wave interferometer detector
with desired sensitivity.Comment: 7 pages, 3 figures. To be published in General Relativity and
Gravitatio
Local channels preserving maximal entanglement or Schmidt number
Maximal entanglement and Schmidt number play an important role in various
quantum information tasks. In this paper, it is shown that a local channel
preserves maximal entanglement state(MES) or preserves pure states with Schmidt
number ( is a fixed integer) if and only if it is a local unitary
operation.Comment: 10 page
(Twisted) Toroidal Compactification of pp-Waves
The maximally supersymmetric type IIB pp-wave is compactified on spatial
circles, with and without an auxiliary rotational twist. All spatial circles of
constant radius are identified. Without the twist, an S compactification
can preserve 24, 20 or 16 supercharges. compactifications can preserve
20, 18 or 16 supercharges; compactifications can preserve 18 or 16
supercharges and higher compactifications preserve 16 supercharges. The
worldsheet theory of this background is discussed. The T-dual and
decompactified type IIA and M-theoretic solutions which preserve 24
supercharges are given. Some comments are made regarding the AdS parent and the
CFT description.Comment: 22 pages REVTeX 4 and AMSLaTeX. v3: References and a paragraph on
nine dimensional Killing spinors were added. v4: A few typos corrected and a
footnote was modifie
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