Vs. pore size

Figure 5.9. Approximate plot of grain size vs. pore size in a sintering ceramic. Arrows indicate sinter paths, the shaded area showing conditions for breakaway of pores from moving grain boundaries. The sinter path of ceramic A crosses the breakaway area and has some rest porosity after sintering. Ceramic B with the same grain size but finer initial pores in the green compact attains theoretical density. With permission from Engineered Materials Handbook, VoL 4, Ceramics and Glasses (1991). ASM International, Materials Park, OH.

Figure 3. Differential pore surface area vs. pore size (343K). It is important to note...

Figure lb. Average fluid density vs. pore size for different bulk pressures (T=195.5 K). 

FIGURE 11.2 Selectivity of several individual pore size columns. This graph shows the resolution capability of Styragel HT 3, HT 4, HT S, and HT 6 columns. The selectivity [Eq. (I)] of these columns vs the molecular weight of polystyrene is plotted. (Courtesy of Waters Corp.)... 

In the case of polyacrylamide gels, Stellwagen [367] found that buffer type (TAE vs TBE) did not affect the apparent pore size (21 mn for 10.5% T 5% C to 200 mn for 4.6% r/2% C), although more extreme variations in salt content and buffer physical properties may very likely strongly affect pore structure in polyacrylamide gels. 

Figure 5. SEC calibration curves random-coil vs. rigid-rod (8) (SEC column set of several pore sizes, N,N-dimethylacetamide solvent at 80°C)...

Figure 3. Pore size from Fig porosimetry data calculated by the (a) Washbum-Laplace equation or the (b) Kloubek-Rigby-Edler equations vs. the pore size from N2 volumetry. Triangle MCM-41 lozenges SBA-15 samples empty symbols intrusion filled symbols retraction. The solid lines correspond to equal diameters from Fig porosimetry and N2 volumetry.

Pore size distribution data obtained from adsorption isotherms and from mercury porosimetric measurements show that in addition to the micropores characteristic of the parent zeolite, the DAY zeolites contain secondary pores with radii of 1.5nm (supermicropores) and lOnm (mesopores) (36,47). The secondary pores in USY-B have a radius of 5nm. It was also shown that the micropore volume of DAY amounts to about 75 percent of that of NaY (36). Due to dealumination and the formation of secondary pores, the total pore volume of DAY is considerably larger than that of NaY zeolite (0.56 vs. 0.29 cc/g). 

Figure 3. Plot of fraction of xenon adsorbed on MCM-41 vs. temperature for MCM-41 samples with various pore sizes.

A large number of heterogeneous catalysts have been tested under screening conditions (reaction parameters 60 °C, linoleic acid ethyl ester at an LHSV of 30 L/h, and a fixed carbon dioxide and hydrogen flow) to identify a suitable fixed-bed catalyst. We investigated a number of catalyst parameters such as palladium and platinum as precious metal (both in the form of supported metal and as immobilized metal complex catalysts), precious-metal content, precious-metal distribution (egg shell vs. uniform distribution), catalyst particle size, and different supports (activated carbon, alumina, Deloxan , silica, and titania). We found that Deloxan-supported precious-metal catalysts are at least two times more active than traditional supported precious-metal fixed-bed catalysts at a comparable particle size and precious-metal content. Experimental results are shown in Table 14.1 for supported palladium catalysts. The Deloxan-supported catalysts also led to superior linoleate selectivity and a lower cis/trans isomerization rate was found. The explanation for the superior behavior of Deloxan-supported precious-metal catalysts can be found in their unique chemical and physical properties—for example, high pore volume and specific surface area in combination with a meso- and macro-pore-size distribution, which is especially attractive for catalytic reactions (Wieland and Panster, 1995). The majority of our work has therefore focused on Deloxan-supported precious-metal catalysts. 

Figure 10. Nyquist plot of the impedance spectrum experimentally measured on the ACFCE at an applied potential of 0.1 V (vs. SCE) in a 30 wt % H2SO4 solution. Dotted and solid lines represent the impedance spectra theoretically calculated based upon the transmission line model (TLM) in consideration of pore size distribution (PSD) and pore length distribution (PLD), respectively. Reprinted with permission from G. -J. Lee, S. -I. Pyun, and C. -H. Kim, J. Solid State Electrochem., 8 (2004) 110. Copyright 2003, with kind permission of Springer Science and Business Media.

FIGURE 8.8 Normalized capacitance (gravimetric capacitance divided by the BET specific surface area) vs. average pore size of a series of CDCs models of the structure of EMI and TFSI ions. (From Largeot, C., et al., J. Am. Chem. Soc., 130, 2730, 2008. With permission.)... 

Parameters of the porous structure of titania samples (pores volume Vs, specific surface area Ssp) were calculated using BET theory [34] from the adsorption isotherms of methanol. The average pore diameter (Dp) values were estimated from the differential curves of pore size distribution. 

Figure 4. Fore size vs. pore volume for coked Shell 244 (Co-Mo on...

In calculations of the mesopore size distribution from physisorption isotherms it is generally assumed (often tacitly) (a) that the pores are rigid and of a regular shape (e.g. cylindrical capillaries or parallel-sided slits), (b) that micropores are absent, and (c) that the size distribution does not extend continuously from the mesopore into the macropore range. Furthermore, to obtain the pore size distribution, which is usually expressed in the graphical form AV /Arp vs. rp, allowance must be made for the effect of multilayer adsorption in progressively reducing the dimensions of the free pore space available for capillary condensation. 

Fig 4. Simulation of the logfanalyte mobility) vs. logfanalyte segment length) at a constant pore size of the separation matrix... 

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