Disc wind models for FU Ori objects

We present disc wind models aimed at reproducing the main features of the strong Na I resonance line P-Cygni profiles in the rapidly-accreting pre-main sequence FU Ori objects. We conducted Monte Carlo radiative transfer simulations for a standard magnetocentrifugally driven wind (MHD) model and our own "Genwind" models, which allows for a more flexible wind parameterisation. We find that the fiducial MHD wind and similar Genwind models, which have flows emerging outward from the inner disc edge, and thus have polar cavities with no absorbing gas, cannot reproduce the deep, wide Na I absorption lines in FU Ori objects viewed at low inclination. We find that it is necessary to include an "inner wind" to fill this polar cavity to reproduce observations. In addition, our models assuming pure scattering source functions in the Sobolev approximation at intermediate viewing angles ($30^{\circ} \lesssim i \lesssim 60^{\circ}$) do not yield sufficiently deep line profiles. Assuming complete absorption yields better agreement with observations, but simple estimates strongly suggest that pure scattering should be a much better approximation. The discrepancy may indicate that the Sobolev approximation is not applicable, possibly due to turbulence or non-monotonic velocity fields; there is some observational evidence for the latter. Our results provide guidance for future attempts to constrain FU Ori wind properties using full MHD wind simulations, by pointing to the importance of the boundary conditions necessary to give rise to an inner wind, and by suggesting that the winds must be turbulent to produce sufficiently deep line profiles.Comment: 12 pages, 17 figures, accepted for publication in MNRA

Sustainable Growth with Environmental Spillovers: A Ramsey-Koopmans Approach

In this paper, we apply the canonical approach of Ramsey, Koopmans, and Diamond to the problem of optimal and intertemporally-equitable growth with a non-renewable resource constraint and show that the solution is sustainable. The model is extended to cases involving environmental amenities and disamenities and renewable resources. The solutions equivalently solve the problem of maximizing net national product adjusted for depreciation in natural capital and environmental effects, which turns out to be both sustainable and constant even without technical change.

Study of Resonantly Stabilized Radicals in Combustion Environments

Resonantly stabilized radicals (RSRs) play an important role in combustion environments due to their high stability resulting from resonance. Many RSRs such as the propargyl, allyl, or benzyl radicals are precursors to the formation of polycyclic aromatic hydrocarbons (PAHs), which can aggregate to form soot. Due to their stability, these RSRs can accumulate in combustion environments in significant quantities. The primary way these radical species are consumed in flames or by reactions with other abundant radicals, by self-recombination of propargyl to form benzene, or in the form of other abundant radicals such as the hydroxyl radical. Experimentally determining the pathways for consumption of these radicals is necessary to better understand soot formation pathways. Product analysis is obtained for the C3H3 + OH reaction using a multiplexed photoionization time-of-flight mass spectrometry coupled to synchrotron radiation at the Advanced Light Source (ALS) of the Lawrence Berkeley National Laboratories in Berkeley, California. Product analysis supports the production of m/z 56, with the predominant isotope formed being acrolein. Notably absent is the presence of propargyl alcohol, which indicates that the allylic form is the most favorable structure. Among the smaller radical exit pathways, the vinyl radical is produced in appreciable quantities, indicating that its coproduct, CO, is a major product of the reaction at higher temperatures. The study of kinetics for these reactions in-house requires proper experimental setup that can provide the necessary conditions such as pressure and temperature. For combustion reactions, higher experimental temperatures are necessary to emulate the conditions in a flame. To this end, a high-temperature fast flow reactor is constructed to provide the necessary conditions for the reaction. Pressure measurements were conducted to obtain the flow velocity, pressure, and temperature of the gas in the high-temperature flow past a standing normal shockwave. The standing normal shockwave is formed by increasing pressure downstream from the supersonic gas expansion to form a differential of pressure between the nozzle and flow cell. To verify the temperature extracted from the pressure measurements, the CN radical was used to determine the temperature of a gas through rotational spectroscopy. CN radicals were produced by pulsed laser photolysis (PLP) at 266 nm from ICN precursor and its concentration is monitored using laser-induced fluorescence (LIF) at an excitation wavelength range of 378 - 382 nm. The rotational spectrum is obtained and analyzed with the PGOPHER software to determine the gas temperature

Incidental music to Maeterlinck's "Pelleas et Melisande" by Gabriel Faure and Jean Sibelius: A Comparative Analysis from a Conductor's Perspective.

An analysis and comparsion of the incidental music composed by Gabriel Faure and Jean Sibelius for Maeterlinck's Pelleas et Melisande. Beginning will talking about background story about Pelleas et Melisande, much of the information about the historical aspect and parallel historical view of art time around late nineteenth century. This paper will briefly touch on the musical mentors, influences, and early musical training of both composers, as well as their relationships to symbolism. This paper will includes survey of the theoretical aspect of both composers

The effect of rectangular and circular fillers on the behavior of bolted joints

Thirty-six bolted tests with either circular washers or rectangular filler plates inserted between the faying surfaces were tested to determine their slip behavior

Mean field approaches to the totally asymmetric exclusion process with quenched disorder and large particles

The process of protein synthesis in biological systems resembles a one dimensional driven lattice gas in which the particles (ribosomes) have spatial extent, covering more than one lattice site. Realistic, nonuniform gene sequences lead to quenched disorder in the particle hopping rates. We study the totally asymmetric exclusion process with large particles and quenched disorder via several mean field approaches and compare the mean field results with Monte Carlo simulations. Mean field equations obtained from the literature are found to be reasonably effective in describing this system. A numerical technique is developed for computing the particle current rapidly. The mean field approach is extended to include two-point correlations between adjacent sites. The two-point results are found to match Monte Carlo simulations more closely

Mergers of binary stars: The ultimate heavy-ion experience

The mergers of black hole-neutron star binaries are calcuated using a pseudo-general relativistic potential that incorporates ${\mathcal O}(v^2/c^2)^3$ post-Newtonian corrections. Both normal matter neutron stars and self-bound strange quark matter stars are considered as black hole partners. As long as the neutron stars are not too massive relative to the black hole mass, orbital decay terminates in stable mass transfer rather than an actual merger. For a normal neutron star, mass transfer results in a widening of the orbit but the stable transfer ends before the minimum neutron star mass is reached. For a strange star, mass transfer does not result in an appreciable enlargement of the orbital separation, and the stable transfer continues until the strange star essentially disappears. These differences might be observable through their respective gravitational wave signatures.Comment: Contribution to QM04 proceedings. Submitted to Journal of Physics