Three-body recombination of ultra-cold atoms to a weakly bound ss level

We discuss three-body recombination of ultra-cold atoms to a weakly bound $s$ level. In this case, characterized by large and positive scattering length $a$ for pair interaction, we find a repulsive effective potential for three-body collisions, which strongly reduces the recombination probability and makes simple Jastrow-like approaches absolutely inadequate. In the zero temperature limit we obtain a universal relation, independent of the detailed shape of the interaction potential, for the (event) rate constant of three-body recombination: $\alpha_{\rm rec}=3.9\hbar a^4/m$, where $m$ is the atom mass.Comment: 10 pages, 3 Postscript figure

Three-body recombination in Bose gases with large scattering length

An effective field theory for the three-body system with large scattering length is applied to three-body recombination to a weakly-bound s-wave state in a Bose gas. Our model independent analysis demonstrates that the three-body recombination constant alpha is not universal, but can take any value between zero and 67.9 \hbar a^4/m, where a is the scattering length. Other low-energy three-body observables can be predicted in terms of a and alpha. Near a Feshbach resonance, alpha should oscillate between those limits as the magnetic field B approaches the point where a -> infinity. In any interval of B over which a increases by a factor of 22.7, alpha should have a zero.Comment: 8 pages, RevTex, 3 postscript figures, uses epsf.sty, rotate.sty, references added, discussion improve

Numerical Analysis of a Swirl Stabilized Premixed Combustor with the Flamelet Generated Manifold approach

In this paper the effectiveness of LES for modeling premixed methane combustion will be investigated in the context of gas turbine modeling. The required reduction of the chemistry is provided by the flamelet generated manifold (FGM) approach of van Oijen (2002). For turbulence-chemistry interactions an algebraic model is used to calculate variations which are used to invoke a pre-assumed pdf, Vreman et al. (2009). The algebraic model has a tunable parameter

Recombinant human interleukin 6 in metastatic renal cell cancer: a phase II trial.

A phase II trial investigating the anti-tumour effects of recombinant human interleukin 6 (rhIL-6) in patients with metastatic renal cell cancer was carried out. RhIL-6 (150 microgram) was administered as a daily subcutaneous injection for 42 consecutive days on an outpatient basis. Forty-nine patients were studied, 12 with and 37 without previous immunotherapy. Forty patients were evaluable for response. A partial remission was noted in two patients, stable disease in 17 and progressive disease in 21. Toxicity was moderate and reversible and consisted mainly of fever, flu-like symptoms, nausea, weight loss and hepatotoxicity. Anaemia, leucocytosis and thrombocytosis and induction of acute phase protein synthesis were noted in most patients. In 15% of the patients anti-IL-6 antibodies developed, and were neutralising in only one patient. Baseline plasma IL-6 concentrations did not correlate with tumour behaviour before or after rhIL-6 treatment. In conclusion, rhIL-6 can be safely administered on an outpatient basis for prolonged period of time and has moderate, reversible toxicity. Its administration induces IL-6-antibody production in only a minority of patients. Antitmour effects of rhIL-6 in metastatic renal cancer are limited

On the combustion of fine iron particles beyond FeO stoichiometry: Insights gained from molecular dynamics simulations

Molecular dynamics (MD) simulations are performed to investigate the thermal and mass accommodation coefficients (TAC and MAC, respectively) for the combination of iron(-oxide) and air. The obtained values of TAC and MAC are then used in a point-particle Knudsen model to investigate the effect on the combustion behavior of (fine) iron particles. The thermal accommodation for the interactions of $\mathrm{Fe}$ with $\mathrm{N_2}$ and $\mathrm{Fe_xO_y}$ with $\mathrm{O_2}$ is investigated for different surface temperature, while the mass accommodation coefficient for iron(-oxide) with oxygen is investigated for different initial oxidation stages $Z_\mathrm{O}$, which represents the molar ratio of $\mathrm{O}/\left(\mathrm{O} + \mathrm{Fe}\right)$, and different surface temperatures. The MAC decreases almost linearly as a function of $Z_\mathrm{O}$, with a steeper slope when $Z_\mathrm{O} < 0.5$ and a gentler slope when $0.5 < Z_\mathrm{O} < 0.57$. By incorporating the MD-informed accommodation coefficients into the single iron particle model, the oxidation beyond $Z_\mathrm{O} = 0.5$ (from stoichiometric $\mathrm{FeO}$ to $\mathrm{Fe_3O_4}$) is modeled. A new temperature evolution for single iron particles is observed compared to results obtained with previously developed continuum models. Specifically, results of the present simulations show that the oxidation process continues after the particle reaching the peak temperature, while previous models predicting a maximum temperature was attained when the particle is fully oxidized to $Z_\mathrm{O} = 0.5$. Since the rate of formation slows down as the MAC decreases with an increasing oxidation stage, the rate of heat loss exceeds the rate of heat release upon reaching the maximum temperature. Finally, the effect of transition-regime heat and mass transfer on the combustion behavior of fine iron particles is investigated and discussed