Mesoscale experiment

This chapter presents a review of the progress relating flammability measurements and properties deduced from microscale experiments of milligram size samples with measurements obtained from mesoscale experiments of sample size about 100 g. We present a comprehensive and integrated approach based on sound scientific method, yet practical for assessing the flammability of nanocomposite polymers in the early stage of their formulations where only milligram order quantities are available. Our approach does not extend to quantum chemistry or molecular dynamics to... 

We have shown in this chapter that microscale measurements can provide a good screening method for the design of fire-resistant materials modified by nanoparticles (and fire retardants) and also, they can be used to quantitatively model and predict the behavior in mesoscale experiments even though an additional parameter is needed to predict the reduced MLR in the mesoscale experiments. The major breakthroughs and challenges are the following ... 

Rheometry of the nanocomposite polymer provides information about the viscosity and shear modulus that can be used to predict the melting behavior in mesoscale experiments. 

A methodology and a new parameter have been developed to quantify the effect of the nanoparticles in reducing the mass loss rate in the mesoscale experiments (i.e., cone) where all other properties have been determined from the microscale experiments. 

It has also been relatively easy to demonstrate the iron limitation in phytoplankton growth in the field. Numerous incubation experiments and a few mesoscale experiments (involving patches of tens of square kilometers of surface ocean) have consistently shown that iron addition promotes phytoplankton growth in high nutrient-low chlorophyll (HNLC) regions of the oceans, including the northern Pacific (Coale et al, 1998 Martin et al, 1989), the equatorial Pacific (Coale et al, 1998 Martin effll., 1994 Price efal., 1991,1994), the Southern Ocean (Boyd et al, 2000), and some... 

The extent to which this imbalance results in carbon flux, however, has yet to be adequately described. The inability to quantify carbon export has primarily been a problem of experimental scale. Even though mesoscale experiments have, for the first time, given us the ability to address the effect of iron on communities, the products of surface water processes and the effects on the midwater column have been difficult to track. For instance, in the IronEx II experiment, a time-series of the enriched patch was diluted by 40% per day. The dilution was primarily in a lateral... 

Pseudoplastic fluids in randomly generated porous media generate effective permeability fields, where zones of constant values are oddly shaped (bottle necks, among others, that can be considered scale up, equivalent to geometrical features, result of our mesoscale experiments), totally abnormal behavior can also be obtained for a different set of parameters. There seems to be a critical value for porosity to keep symmetric effective permeability fields. Our results can be used as models for materials with several zones... 

In principle, mesoscale methods can provide a means for connecting one type of simulation to another. For example, a molecular simulation can be used to describe a lipid. One can then derive the parameters for a lipid-lipid potential. These parameters can then be used in a simulation that combines lipids to form a membrane, which, in turn, can be used to compute parameters describing a membrane as a flexible sheet. Such parameters could be used for a simulation with many cells in order to obtain parameters that describe an organ, which could be used for a whole-body biological simulation. Each step, in theory, could be modeled in a different way using parameters derived not from experiment but from a more low-level form of simulation. This situation has not yet been realized, but it is representative of one trend in computational technique development. 

Underlying all continuum and mesoscale descriptions of shock-wave compression of solids is the microscale. Physical processes on the microscale control observed dynamic material behavior in subtle ways sometimes in ways that do not fit nicely with simple preconceived macroscale ideas. The repeated cycle of experiment and theory slowly reveals the micromechanical nature of the shock-compression process. 

Rue, E. L., and K. W. Bruland. 1997. The role of organic complexation on ambient iron chemistry in the equatorial Pacific Ocean and the response of a mesoscale iron addition experiment. Limnology and Oceanography 42 901—910. 

The need for further exploration of electronic orders and inhomogeneities in oxides is evident. Experiments need to be designed so as to isolate long-range strain effects, with theoretical efforts towards building coarse-grained models to understand the mesoscale physics. This issue is particularly important for exploiting the electronic softness of these materials for applications. 

Cochlan WP (2001) The heterotrophic bacterial response during a mesoscale iron enrichment experiment (IronEx II) in the eastern Equatorial Pacific Ocean. Limnol Oceanogr 46 428 135... 

Verity PG, Villareal TA, Smayda TJ (1988) Ecological investigations of blooms of colonial Phaeocystis pouchetti - 1. Abundance, biochemical composition, and metabolic rates. J Plankton Res 10(2) 219-248 Watson SW, Novitsky TJ, Quinby HL, Valois FW (1977) Determination of bacterial number and biomass in the marine environment. Appl Environ Microbiol 33 940-946 Weaver RS, Kirchman DL, Hutchins DA (2003) Utilization of iron/organic ligand complexes by marine bacterioplank-ton. Aquat Microb Ecol 31 227-239 Weinbauer MG, Arrieta JM, Hemdl GJ (2003) Stimulation of viral infection of bacterioplankton during a mesoscale iron fertilization experiment in the Southern ocean. Geo-phys Res abstracts 5 12280... 

Mesoscale self-assembly We have not yet modeled MESA by computer, but with the wealth of experimental results we are in a position to develop believable computer simulations calibrated by experiment. The force of attraction between the objects is well understood mathematically in a number of cases [33,120] and in some systems it may be possible to measure these forces experimentally [149]. Some of the problems encountered in modeling molecular systems will also be encountered in modeling MESA. For example, finding global rather than local minima, the availability of computer time limiting how long the assembly can be modeled, and constructing potential functions for interactions that have not been determined... 

Cochlan, W. P., Herndon, J., Betts, J. N., Costello, D. R., Trick, C. G., Wells, M. L. (2005). Ammonium inhibition of nitrate uptake during mesoscale iron-enrichment experiments A comparison of the planktonic response during SOFeX and SEEDS II. SEEDS II Workshop Second Iron Enrichment Experiment in the western subarctic Pacific, Tokyo, Japan, October 2005 (Abstract). Cochlan, W. P., Kudela, R. M. (2006). The Southern Ocean iron enrichment experiment the nitrogen uptake response. In Report of the 2004 Workshop on In Situ Iron Enrichment Experiments in the Eastern and Western Subarctic Pacific (Takeda, S., and Wong, C. S., eds.), PISCES Scientific Report 31, pp. 27—31. 

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