Mass function

It is user friendly and possesses a graphical user interface for developing the flow paths, ventilation system, and initial conditions. The FIRIN and CFAST modules can be bypassed and temperature, pressure, gas, release energy, mass functions of time specified. FIRAC i.s applicable to any facility (i.e., buildings, tanks, multiple rooms, etc,) with and without ventilation systems. It is applicable to multi species gas mixing or transport problems, as well as aerosol transport problems, FIRAC includes source term models for fires and limitless flow paths, except the FlRlN fire compartment limit of to no more than three... 

MMFTD Molecular mass functional type (2) Polyoxyethylene... 

Table 7. Molecular masses, functionalities, calculated and measured radii of gyration, and translational diffusion coefficients of the investigated polyisoprene stars...

The paper first considers the factors affecting intramolecular reaction, the importance of intramolecular reaction in non-linear random polymerisations, and the effects of intramolecular reaction on the gel point. The correlation of gel points through approximate theories of gelation is discussed, and reference is made to the determination of effective functionalities from gel-point data. Results are then presented showing that a close correlation exists between the amount of pre-gel intramolecular reaction that has occurred and the shear modulus of the network formed at complete reaction. Similarly, the Tg of a network is shown to be related to amount of pre-gel intramolecular reaction. In addition, materials formed from bulk reaction systems are compared to illustrate the inherent influences of molar masses, functionalities and chain structures of reactants on network properties. Finally, the non-Gaussian behaviour of networks in compression is discussed. 

The properties of a polymer network depend not only on the molar masses, functionalities, chain structures, and proportions of reactants used to prepare the network but also on the conditions (concentration and temperature) of preparation. In the Gaussian sense, the perfect network can never be obtained in practice, but, through random or condensation polymerisations(T) of polyfunctional monomers and prepolymers, networks with imperfections which are to some extent quantifiable can be prepared, and the importance of such imperfections on network properties can be ascertained. In this context, the use of well-characterised random polymerisations for network preparation may be contrasted with the more traditional method of cross-linking polymer chains. With the latter, uncertainties can exist with regard to the... 

We do not find any stars with low [C/N] ratios and the range of [C/N] we find is much more restricted than predicted. If a standard initial mass function is used, we would expect about one in five AGB stars to undergo hot-bottom-burning, a ratio not seen in Fig. 1. It is possible that some of the C-rich stars in our sample were polluted by nucleosynthesis sources other than AGB stars, and we are currently observing a larger sample of stars. There are also many assumptions which need to re-evaluated, such as mass loss being unaffected by... 

Fig. 4. The yields for models without rotation x IMF (initial mass function), from [5].

The model evolution of rotating stars has been pursued up to the presupernova stage [5], since we know that nucleosynthesis is also influenced by rotation [4]. Figs. 4 and 5 show the chemical yields from models without and with rotation. These figures shows these yields multiplied by the initial mass function (IMF). The main conclusion is that below an initial mass of 30 Mq, the cores are larger and thus the production of a-elements is enhanced. Above 30 Mq,... 

Nowadays, the star formation history (SFH), initial mass function (IMF) and detailed chemical properties have been determined for many dwarfs, both in the Local Group and outside it (e.g. Grebel, Shetrone, Tolstoy, these proceedings). This in principle allows us to base theories of late-type galaxy formation and evolution on firmer grounds, by reducing the free parameter space. 

An initial mass function usually (but not always) the Salpeter function (see Chapter 7) is assumed. 

Starburst 99 (Leitherer et al. 1999, 2001) gives synthetic spectra for actively star-forming galaxies assuming a selection of different ages, metallicities and initial mass functions. 

Fig. 5.11. Amounts, in units of relative Solar-System abundances, of nuclear species resulting from hydrostatic evolution of an average pre-supernova. Filled circles represent an initial mass function with slope -2.3 and plus signs one with slope -1.5. The dashed box encloses 28 species co-produced within a factor of 2 of solar values, assuming a vlC.(u. y)16O rate 1.7 x that given by Caughlan and Fowler (1988). Reprinted from Weaver and Woosley (1993). Reproduced with kind permission of Elsevier Science. Courtesy Tom Weaver.

After van den Hoek Groenevegen (1997), with their standard parameters, except that for Z = 0.001 the mass loss parameter t) in the Reimers (1975) formula is 1 instead of 4. The lowest block represents the overall yields contributed by intermediate-mass stars in a population governed by a Salpeter mass function between 0.1 and 120 M , calculated from the above stellar yields by Marigo (2001), to be compared with solar abundances (by mass) given in the second line. 

Galactic chemical evolution basic concepts and issues 7.3.3 Initial mass function (IMF)... 

Salpeter introduces the Initial Mass Function for star formation. 

Scalo, J.M. 1998, in G. Gilmore D. Howell (eds.), The Stellar Initial Mass Function, ASP Conf. Series, 142, 201. 

The mass function, which is a pure combination of observables, is a lower limit to the possible mass of star 2 if the orbit is other than edge-on (that is, if % < 90°) or the observed star has mi > 0, then m2 > / Thus, observation of one star constrains the mass of the other star. Note, incidentally, that in a neutron star binary system with a high-mass companion (mi m2), / is low... 

This theory assumes the definition of (i) the frame of discernment Q consisting of the exhaustive and exclusive h3rpothesis and (ii) the reference set 2 of all the disjunctions of the elements of fi. The Evidence theory defines the basic belief assignment (bba) function as an elementary mass function m 2 —> [0,1] verif3dng for all elements A of 2 ... 

Based on these definitions, combination operators can be defined. For example, it is possible to build a unique elementary mass function m from two... 

A compound is flagged as either active or inactive on the basis of the activity threshold determined as in Section 6.2.2. The probability that the observed number of actives x occurs in a cluster of size n given a background hit rate p (expressed as a fraction) is determined by the binomial probability mass function [38], shown as follows ... 

The second parameter, the initial mass function, serves to weight the contributions of stars with different masses in proportion to their number within a single generation. The initial mass function has been established empirically and appears to remain fairly stable in time. The number of stars of mass M is inversely proportional to the cube of M, to a first approximation, provided we exclude the slightest of them M < Mq). Looking at the mass distribution at birth, once established, we notice immediately how rare the massive stars are. For every star born at 10 Mq, there are a thousand births of solar-mass stars. 

Assuming that the initial mass function is invariable, we may calculate the average production of the various star generations, born with the same metaUicity, and estimate their contribution to the evolution of the galaxy (see Appendix 4). The abundances produced by a whole population are not as discontinuous and irregular as those shown in the table of individual yields (Table A4.1). This is because the latter are averaged over the mass distribution. 

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