Velocity total mass

The initial velocities are often adjusted so that the total momentum of the system is zer Such a system then samples from the constant NVEP ensemble. To set the total line momentum of the system to zero, the sum of the components of the atomic momen along the x, y and z axes is calculated. This gives the total momentum of the system each direction, which, when divided by the total mass, is subtracted from the atom velocities to give an overall momentum of zero. 

Approaches used to model ozone formation include box, gradient transfer, and trajectoty methods. Another method, the particle-in-cell method, advects centers of mass (that have a specific mass assigned) with an effective velocity that includes both transport and dispersion over each time step. Chemistry is calculated using the total mass within each grid cell at the end of each time step. This method has the advantage of avoiding both the numerical diffusion of some gradient transfer methods and the distortion due to wind shear of some trajectory methods. 

The reactor volume is calculated from Mj and the bulk density of the catalyst material, (-r ) depends not only on composition and temperature, but also on the nature and size of the catalyst pellets and the flow velocity of the mixture. In a heterogeneous reaction where a solid catalyst is used, the reactor load is often determined by the term space velocity, SV. This is defined as the volumetric flow at the inlet of the reactor divided by the reaction volume (or the total mass of catalyst), that is... 

In heat transfer applications, this jacket is considered a helical coil if certain factors are used for calculating outside film coefficients. The equivalent heat transfer diameter, D, for a rectangular cross-section is equal to 4 w (w being the width of the annular space). Velocities are calculated from the actual cross-section of the flow area, pw (p being die pitch of die spiral baffle), and die effective mass flowrate W dirough die passage. The effective mass flowrate is approximately 60% of die total mass flowrate of die jacket. 

A truck carr) ing two tanks containing a very unstable and hazardous gas is involved in an accident that results in tlie consecutive explosion of the tanks -one innncdiately, the second approximately a minute later. The total mass of tlie emission resulting from the explosion of each tank is 30,000 g. The wind velocity is 1 m/s from the north, and tlie effective height of emission is 30 meters at the time of tlie accident. Calculate the concentration of tliis gas at 500 meters south but 100 meters east from the site 10 minutes after tlie explosion of tlie first tank. Assume tliat stability category D applies. 

Hughmark and Pressburg (H14) studied holdup and pressure drop for cocurrent gas-liquid flow, and correlated holdup with a function of gas and liquid flow rates, surface tension, densities of gas and liquid, viscosities of gas and liquid, and total mass velocity. 

In Section I, a qualitative schematic description of the main connection between increased agitation intensity and increased total mass-transfer rate was given. It can readily be seen from this description that further research in gas and liquid flow patterns and in the area of relative bubble velocities in dispersions will contribute to the basic knowledge necessary for understand ing the real mechanisms occurring in these systems. 

We add to Eqs. (9.15-9.17) and (9.21-9.25) the total mass and energy balances to determine the vapor velocity and the temperature at the outlet cross-section... 

The ribosomal subunits are defined according to their sedimentation velocity in Svedberg units (40S or 60S). This table illustrates the total mass (MW) of each. The number of unique proteins and their total mass (MW) and the RNA components of each subunit in size (Svedberg units), mass, and number of bases are listed. 

When the concentration profile is fully developed, the mass-transfer rate becomes independent of the transfer length. Spalding (S20a) has given a theory of turbulent convective transfer based on the hypothesis that profiles of velocity, total (molecular plus eddy) viscosity, and total diffusivity possess a universal character. In that case the transfer rate k + can be written in terms of a single universal function of the transfer length L and fluid properties (expressed as a molecular and a turbulent Schmidt number) ... 

The homogeneous model also assumes that both phases are moving at the same velocity, i.e., no slip. Because the total mass flux is constant, the acceleration (or kinetic energy change) term can be written... 

At an inflow boundary, the mean velocity vector will point into the flow domain. If we denote the component of the mean velocity normal to the inflow surface (Sin) by U n, then the total mass entering the system in time step At is34... 

The total mass flux of A under the condition of the burning of a condensed phase, which imposes a bulk velocity developed from the mass burned, is then... 

Wallis states that if bubbles were uniformly dispersed, and nonrigid, then their effect at a constant total mass-flow rate would be simply to increase the stream velocity, and at a constant friction factor, the pressure-drop would be,... 

The decrease in film burn-out heat flux with increasing mass velocity of flow at constant quality has been explained by Lacey et al. in the following way. At constant quality, increasing total mass flow rate means increasing mass flow of vapor as well as liquid. It has been shown that above certain vapor rates increased liquid rates do not mean thicker liquid layers, because the increased flow is carried as entrained spray in the vapor. In fact, the higher vapor velocity, combined with a heat flux, might be expected to lead to easy disruption of the film with consequent burn-out, which seems to be what actually occurs at a constant steam mass velocity over very wide ranges of conditions—that is, the critical burn-out steam quality is inversely proportional to the total mass flow rate. 

Variables Affecting Measurement Flow measurement methods may sense local fluid velocity, volumetric flow rate, total or cumulative volumetric flow (the integral of volumetric flow rate with respect to elapsed time), mass flow rate, and total mass flow. 

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