21,522 research outputs found
Constitutive behaviour of the metastable stainless steel: Sandvik Nanoflex
This article presents a model to describe the constitutive behaviour of corrosion-resistant Sandvik steel NanoflexTM [1] during metal forming and hardening. This material is characterised by different phenomena. The material is metastable, which causes strain-induced transformation to take place during metal forming. Depending on the annealing conditions, the material also transforms isothermally [2, 3] (as opposed to a-thermal martensite). This transformation can also take place immediately after forming, as a result of the residual stresses present in the material. The martensite phase of this material can be aged [4]. Results of the various measurements on Sandvik NanoflexTM are shown. The measurements mainly involved tensile tests and upsetting tests, during which both isothermal transformation and strain-induced transformation were measured by inductive sensors[5] and they were afterwards examined. The hardening of the material and the increase in hardness during ageing was also examined.\ud
Finally, a constitutive model based on literature and the measurement are presented. This model describes the isothermal,\ud
stress-assisted transformation, strain-induced transformation, work hardening and ageing. The model has been set up in such\ud
a way that it can be simply implemented in a FEM cod
A New State of Baryonium
The recent discovery of a narrow resonance in the decay is described as a zero baryon number,
``deuteron-like singlet '' state. The difference in binding energy
of the deuteron (-2.225 MeV) and of the new state (-17.5 MeV) can be accounted
for in a simple potential model with a confining
interaction.Comment: 7 page
Charmless B Decays to Final States with Radially Excited Vector Mesons
We consider the weak decays of a B meson to final states that contain a
S-wave radially excited vector meson. We consider vector-pseudoscalar final
states and calculate ratios of the type , and where , and
are higher , and S-wave radial
excitations. We find such decays to have larger or similar branching ratios
compared to decays where the final state , and are in the
ground state. We also study the effect of radial mixing in the vector system
generated from hyperfine interaction and the annihilation term.Comment: Latex, 12 pages, one figur
Malaria and National Income: Examining a Two Way Causal Relationship
Simple plots of data show that malaria has a negative correlation with national income per capita, whether looking across countries at a point in time, or looking at a single country over time. Some countries have been able to move from an equilibrium characterized by low income and high malaria, to a new equilibrium with higher income and lower rates of malaria. This study develops and estimates a simultaneous equations model to explain these changes. We distinguish three potential causal chains: (a) the ability for decreases in malaria to increase income, (b) the ability for increases in income to reduce malaria (reverse causality), and (c) external factors that may lead to both higher income and lower malaria (incidental association). We find that changes in income have a much stronger effect on malaria than the other way around. While a 1% rise in the number of malaria cases per million decreases income per capita by less than 0.01%, a 1% rise in income per capita decreases the number of malaria cases per million by more than 1.1%. If income were just 1% higher in the 100 countries of the sample, 603,189 cases of malaria could be averted annually.antipoverty, GDP, health, economic growth, malaria, simultaneous equations, Health Economics and Policy, International Development, Labor and Human Capital, I1, I3, O1, O2,
Phonon runaway in nanotube quantum dots
We explore electronic transport in a nanotube quantum dot strongly coupled
with vibrations and weakly with leads and the thermal environment. We show that
the recent observation of anomalous conductance signatures in single-walled
carbon nanotube (SWCNT) quantum dots can be understood quantitatively in terms
of current driven `hot phonons' that are strongly correlated with electrons.
Using rate equations in the many-body configuration space for the joint
electron-phonon distribution, we argue that the variations are indicative of
strong electron-phonon coupling requiring an analysis beyond the traditional
uncorrelated phonon-assisted transport (Tien-Gordon) approach.Comment: 8 pages, 6 figure
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