A comparative study of the porosity of doped graphites by small angle neutron scattering, nitrogen adsorption and helium pycnometry

Contemporary Approach to the Porosity of Dental Materials and Methods of Its Measurement

“…These include (among others): small and ultra-small angle neutron scattering (SANS and USANS), and small and ultra-small angle X-ray scattering (SAXS and USAXS), computed microtomography (CMT), nuclear magnetic resonance (NMR), as well as X-Ray, optical, AFM, TEM, SEM, FEM, and ESEM microscopy [119][120][121][122]. SAXS and SANS measurements, especially combined with ultra SAXS or ultra-SANS and with a proper contrast matching technique, provide information on total porosity, with differentiation to open and closed pores [119,123], as well as on the distribution of pore sizes, pore morphology, or fractal nature of pore matrix interfaces. These methods enable the observation of objects from about 1 nm (10 Å) to about 1µm (200,000 Å) [124].…”

The use of small angle neutron scattering with contrast matching and variable adsorbate partial pressures in the study of porosity in activated carbons

“…There have been few previous efforts to apply this complete technique to porous carbons although Diduszko et al [6] have compared pore size distributions in activated carbons as determined from SAXS with those derived from vapor adsorption curves. Further He et al [7] have used the contrast matching method to study porosity in carbide-derived carbons while Mergia et al [8] [9] have applied the SANS contrast match/partial pressure variation method to study the hierarchical pore geometry in a meso-porous silica. In the present carbons, as a result of the activation process applied -which presumably gives rise to progressively narrowing pore networks -no hysteresis loops are observed in the vapor adsorption isotherms, no percolation network is generated and hence the SANS simply gives a reversible measure of the unfilled pore volume as function of the partial pressure.…”

In-situ neutron imaging of hydrogenous fuels in combustion generated porous carbons under dynamic and steady state pressure conditions

“…In order to get an independent estimate of p, we had the skeletal density measured by the helium pycnometry technique (see e.g [29,30] for examples given by other groups) yielding averages below 1.4 g cm -3 . For p = 1.34, from one of the pycnometry results, the model described in this work yields coefficient b = 4.0010 -4 , a/b = 0.625 (the a-coefficient used was 2.5010 -4 ), and resulting FVF = 0.924, i.e., in good agreement with the low level of porosity found from HRTEM and neutron radiography analysis.…”

“…Information on particles and pores can be achieved from X-ray and neutron scattering, SAXS and SANS (see e.g. [6] for X-ray and particles, and [30] for SANS and pores), which present different sensitives with respect to the atomic number of species and can yield complementary information on the size distribution function and of particles and pores. X-ray and neutron scattering have also been used to determine atomic pair distribution functions and the spatial distribution of atomic species for metallic alloys employed for hydrogen storage studies [31,32].…”