scholarly journals Porous MgTi2O5/MgTiO3 composites with narrow pore-size distribution: in situ processing and pore structure analysis

2010 ◽  
Vol 118 (1381) ◽  
pp. 819-822 ◽  
Author(s):  
Yoshikazu SUZUKI ◽  
Masafumi MORIMOTO
2016 ◽  
Vol 69 (2) ◽  
pp. 183 ◽  
Author(s):  
Juanrong Chen ◽  
Fengxian Qiu ◽  
Ying Zhang ◽  
Shunsheng Cao

A new trend in supercapacitor research has focussed on the construction of inexpensive electrode materials with high capacitor performances. In this study, we demonstrate the successful preparation of carbon-doped hollow titania spheres. The as-prepared titania spheres not only exhibit an advantage over existing methods because they are created in situ by directly carbonizing cationic polystyrene templates without the addition of carbon precursors, but also feature a narrow pore size distribution and a tuneable shell architecture. When the materials were applied as supercapacitor anodes, the electrochemical results reveal the superior performances of the supercapacitors over that of commercial P25. The higher performances were attributed to carbon doping. Thus, the reported C-doped hollow titania shows more potential as electrode materials for high-performance supercapacitors.


1990 ◽  
Vol 180 ◽  
Author(s):  
Douglas M. Smith ◽  
Pamela J. Davis ◽  
C. Jeffrey Brinker

ABSTRACTThe use of NMR relaxation measurements for the in-situ study of pore structure evolution during gel aging and drying is illustrated. The change in the pore size distribution and surface area of both wet and dried gels is examined as a function of aging conditions including temporal aging, thermal aging, changing pH, and changing pore fluid. The effect of pore fluid pH on dissolution/reprecipitation in ordered packings of monodisperse silica spheres is also examined as a model system for particulate gels. As expected, the pore size distribution narrows with increasing time of treatment in high pH pore fluids. Interpretation of high pH results for the wet state is complicated by a microporous layer which forms on colloidal silica resulting in significantly larger wet surface area as compared to the final dried material. Narrowing of the pore size distribution, which is of interest for maximizing drying rates, is maximized in the least time by using either high pH or repeated ethanol washes for the base-catalyzed gel (B2) used.


2021 ◽  
Vol 11 (5) ◽  
pp. 2113-2125
Author(s):  
Chenzhi Huang ◽  
Xingde Zhang ◽  
Shuang Liu ◽  
Nianyin Li ◽  
Jia Kang ◽  
...  

AbstractThe development and stimulation of oil and gas fields are inseparable from the experimental analysis of reservoir rocks. Large number of experiments, poor reservoir properties and thin reservoir thickness will lead to insufficient number of cores, which restricts the experimental evaluation effect of cores. Digital rock physics (DRP) can solve these problems well. This paper presents a rapid, simple, and practical method to establish the pore structure and lithology of DRP based on laboratory experiments. First, a core is scanned by computed tomography (CT) scanning technology, and filtering back-projection reconstruction method is used to test the core visualization. Subsequently, three-dimensional median filtering technology is used to eliminate noise signals after scanning, and the maximum interclass variance method is used to segment the rock skeleton and pore. Based on X-ray diffraction technology, the distribution of minerals in the rock core is studied by combining the processed CT scan data. The core pore size distribution is analyzed by the mercury intrusion method, and the core pore size distribution with spatial correlation is constructed by the kriging interpolation method. Based on the analysis of the core particle-size distribution by the screening method, the shape of the rock particle is assumed to be a more practical irregular polyhedron; considering this shape and the mineral distribution, the DRP pore structure and lithology are finally established. The DRP porosity calculated by MATLAB software is 32.4%, and the core porosity measured in a nuclear magnetic resonance experiment is 29.9%; thus, the accuracy of the model is validated. Further, the method of simulating the process of physical and chemical changes by using the digital core is proposed for further study.


Author(s):  
Petra Foerst ◽  
M. Lechner ◽  
N. Vorhauer ◽  
H. Schuchmann ◽  
E. Tsotsas

The pore structure is a decisive factor for the process efficiency and product quality of freeze dried products. In this work the two-dimensional ice crystal structure was investigated for maltodextrin solutions with different concentrations by a freeze drying microscope. The resulting drying kinetics was investigated for different pore structures. Additionally the three-dimensional pore structure of the freeze dried samples was measured by µ-computed tomography and the pore size distribution was quantified by image analysis techniques. The two- and three-dimensional pore size distributions were compared and linked to the drying kinetics.Keywords: pore size distribution; freeze drying; maltodextrin solution; freeze drying microscope   


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