Nodule size distributions

Broadhead and Tresco studied the effects of fabrication conditions on the structures and performances of membranes formed from poly(acrylonitrile-vinylchloride) (PAN-PVC) by using the phase inversion process [85]. They reported the relationship of the fine-surface structure of PAN-PVC membranes to the membrane performance and membrane fabrication method. The fine-surface structure of nodular elements and the size of these elements could be altered by changing the precipitation conditions. Membranes were prepared at 22 on 55 mm diameter polished silicon wafers by spinning at 1500 rpm for 20 s with a spin coater [86]. The film was immediately precipitated in one of the four different precipitation media. The first three media consisted of deionized water at 4,22, and 54 °C. These membranes were referred to as Type 1 , Type 2 , and Type 3 , respectively. The fourth medium was a 50/50 mixture of deionized water and N,iV-dimethylformamide (DMF) at 54 °C and coded as Type 4 . Figure 4.53 shows the histograms of the nodule size distributions observed at the skinned surface of the membranes made under four different precipitation conditions. The sizes of these nodular elements became smaller and more uniform with milder precipitation conditions, which supports the theory that nodules are formed through spinodal decomposition under these conditions. In addition, the size of these nodules could be related to water permeability. Hence, water transport occurred through the interstitial spaces where the pores could be situated. 

Fig. 4.53a-d. Histograms of the nodule size distribution observed at the skinned surface of membranes made under different precipitation conditions aType 1, bType 2,cType 3, and d Type4. Please note the shift in size and dispersiveness of the nodular elements. Reprinted from [85]. Copyright 1998, with kind permission from Elsevier... 

Abaidoo RC, Keyser HH, Singleton PW, Dashiell KE, Sanginga N (2007) Population size, distribution, and symbiotic characteristics of indigenous Bradyrhizobium spp. that nodulate TGx soybean genotypes in Africa. Appl soil Ecol 35(1) 57—67... 

Table 3.2 shows the influence of the initial PEI concentration on the resulting particle size distribution. Both the size and the number of PEI domains increased in the sea-island morphology, whereas the size of thermoset nodule decreased and the number of nodules increased in the nodular morphology as the initial PEI concentration was increased. 

Figure 4. Gray-scale synchrotron-based micro-X-ray radiation fluorescence (pSXRF) maps in negative contrast showing the distribution of some elements in a soil nodule from the Morvan region, France (Baize and Chretien 1994 Latrille et al. 2001 Manceau et al. 2002b). All maps except Fb were obtained by scanning the soil nodule under a monochromatic beam with an energy of 12,985 eV (Pb L3-edge - 50 eV). The Pb map was obtained by subtraction of the normalized maps taken 50 eV above and below the Pb Le-edge to eliminate the contribution from As. Nodule size 3 x 3.5 mm, beam size 16 pm H x 6 pm V step size 16 x 16 pm dwell time 250 ms/point. Data were recorded on beamline 10.3.2 at the ALS (Beikeley).

In general, the accessibility of functional sites is determined by the relationship between the dimensions of the pores and of solute molecules. The peculiar behavior of macroporous resins logically follows from the bimodal character of their pore size distribution. Space between the primary nodules and their aggregates presents transport channels with easily accessible functional groups on their walls. When the porous support was formed in the presence of a solvating diluent, such as toluene, its transport... 

Important membrane surface properties include the size of nodules and nodule aggregates, the shape of pores, the pore size and pore size distribution, and the surface roughness. In this chapter, the focus will be on nodules and nodular aggregates since AFM seems most suitable for those. Moreover, there is evidence that nodular structure has some relationship to membrane performance. 

Adventitious mineral matter is transformed directly to ash in the combustion zone. Depending on the temperature-time history, the ash particles will be spherical or semirounded. The size distribution of this ash depends on the size distribution of the adventitious mineral matter. Intrinsic mineral matter forms ash nodules in the pores of the char, and as char burnout proceeds, the ash nodules coalesce on the surface of the char. 

The pitting corrosion was due mainly to galvanic action between the FA and the stainless steel support rack. The fuel plate cladding (1060) and the side plate (6061 T6) also formed a galvanic pair, and the corrosion associated with this pair was less intense. Many FAs were inspected later with an underwater video camera. The pitting corrosion nodules, their sizes, distribution and location were investigated. 

Morphology. Morphologically, carbon blacks differ in primary particle or nodule size, surface area, aggregate size, aggregate shape, and in the distribution of each of these. 

Primary Particle (Nodule) Size. Although the smallest discrete entity of carbon black is the aggregate, the particle size, and its distribution is one of the most important morphological parameters with regard to its end-use applications. 

Two types of well defined branched polymers are acessible anionically star-shaped polymers and comb-like polymers87 88). Such macromolecules are used to investigate the effect of branching on the properties, 4n solution as well as in the the bulk. Starshaped macromolecules contain a known number of identical chains which are linked at one end to a central nodule. The size of the latter should be small with respect to the overall molecular dimensions. Comb-like polymers comprise a linear backbone of given length fitted with a known number of randomly distributed branches of well defined size. They are similar to graft copolymers, except that backbone and branches are of identical chemical nature and do not exhibit repulsions. 

Swelling data for Sty-co-DVB polymers that have very-narrow-range molecular weight distributions for the poly(styrene) segments between poly(DVB) nodules have been reported by Rempp [141-143] and his coworkers. The size of these nodules and the number of polystyrene segments covalently bonded to a given... 

Dusty clinker (poor nodulization) and snowmen (a) Unfavorable temperature distribution (b) Too little melt (c) Too much coarse quartz, lime, slag (d) Heavy alkali circulation resulting in early crystal growth of belite and free lime and large silicate crystal size (Miller, 1980)... 

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