Conveyor Belt Model

Van der Weij s (1932) comparison of the transport system with a unidirection-ally moving conveyor belt loaded with different amounts of auxin molecules was a first attempt to conceptualize the basipetal auxin transport mechanism. It is noteworthy that this rather mechanistic picture, which has found little experimental basis, has had something of a revival by assuming plasmalemma-somes to be possible vehicles of auxin transport (Wangermann and Withers 1978 see Fig. 3.7). 

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Figure 12. An example of use of to assess the rate and depth of sediment mixing from a core on the slopes of the Bahamas (Henderson et al. 1999b). The exponential decrease in Pbxs seen in the upper 6 cm of the sediment reflects decay of °Pb as it is mixed downward. The diffusional model of mixing described in the text indicates a mixing rate, D, of 51 cm kyr for this core. The two circled points at greater depth reflect rapid injection of surface material to depth in a process known as conveyor-belt feeding (Robbins 1988 Smith et al. 1997).

Robbins JA (1988) A model for particle-selective transport of tracers in sediments with conveyor-belt deposit feeders. Journal of Geophysical Research 91 8542-8558 Robinson LF, Belshaw NS, Henderson GM (in press) U and Th isotopes in seawater and modem carbonates from the Bahamas. Geochim Cosmochim Acta Rosenthal Y, Boyle EA, Labeyrie L, Oppo D (1995a) Glacial enrichments of authigenic Cd and U in subantarctic sediments A climatic control on the elements oceanic budget Paleoceanography 10(3) 395-413... 

A reactor model based on solid particles in PF may be used for situations in which there is little or no mixing of particles in the direction of flow. An example is that of a conveyor belt carrying the particles others that approximate this include a rotating... 

Robbins, J. A., A model for particle-selective transport of tracers in sediments with conveyor belt deposit feeders , J. Geophys. Res., 91, 8542-8558 (1986). 

The degradation model of three samples (cushioned coal, initial 10% fines and initial 30% fines) of South Blackwater coal is determined on three impact surfaces (steel plate, conveyor belt and coal stockpile). Degradation model equation can be written as follows ... 

Lowndes et al. [91] used the commercial CFD model Fluent to simulate flame spread along a conveyor belt. Fluent, at the time this modeling was conducted, did not contain a conventional pyrolysis model in the sense that is normally implied in the fire literature. Instead, the authors adapted a discrete phase model, which is intended to simulate the combustion of pulverized coal. 

Essentially, the conveyor belt was approximated as an ensemble of combustible particles. This approach is similar to the treatment of natural fuels such as trees and shrubs in the experimental version of FDS known as Wildland Urban Interface FDS (WFDS) [92], Fowndes et al. [91] found that the model qualitatively replicated the flame spread that was observed experimentally. However, no quantitative comparison between modeled pyrolysis front position or HRR and analogous experimental data was given. Modeling a single continuous surface, such as a conveyor belt, as an ensemble of combustible particles is a novel idea, but it is not clear in this particular case whether the relevant physics of condensed-phase pyrolysis were accurately represented. 

Lowndes, I.S., Silvester, S.A., Giddings, D., Pickering, S., Hassan, A., and Lester, E. The computational modeling of flame spread along a conveyor belt. Fire Safety Journal, 2007.42, 51-67. 

An RFC model QC-1202 processor was used for UV curing. The unit was equipped with two 12 Inch medium pressure mercury arc lamps and a variable speed conveyor (50 to 500 ft/min). Only one lamp was used at a time In the testing (operated at 200 watts/ln). The DV energy dosage was measured by passing a UV Process Supply Compact Radiometer under the lamp on the conveyor belt. 

Kiranoudis et al. [20] developed a dynamic model for the simulation of conveyor-belt dryers and proposed a SISO (single-input, single output) control scheme for the regulation of material moisture content. In a subsequent work, Kiranoudis et al. [21] extended the dynamic model of this process to include MIMO (multiple-input, multiple output) schane to control the material moistme content and temperature. In both works, PI controllers were appropriately tuned and nonlinear simulations were performed. 

Shuttle car A rubber-tired vehicle used to haul coal from the continuous miner or loader to a belt feeder or conveyor belt. It is usually electrically powered, with the power supplied through a trailing cable. Some new models are equipped with diesel engines. 

In certain models, the bins, particularly those of fine aggregates, are equipped with a vibrating system. This eliminates the development of caves within the bins when aggregates are damp during discharge of aggregates to the conveyor belt. 

TABLE XXXIV Model Conveyor Belt Cover... 

Models that simulate nonlocal mixing by conveyor-belt species are available and are used primarily for process hypothesis testing. Those that use advection of particles are the most realistic and many retain a diffusive term as well. Few data are available to establish the nonlocal reworking rates and related feeding depth parameters needed for these models. 

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