نتایج جستجو برای: micro pore

تعداد نتایج: 154037  

2006
R. N. Maiti R. Khanna P. K. Sen K.D.P. Nigam

A conceptual pore level model (Chem. Eng. Sci. 57 (2002) 3401) of spreading of liquid over internally wet porous particles is applied to explain reported rector level enhancement in wetting of trickle bed reactor (Ind. Eng. Chem. Res. 36 (1997) 5133). It is con6rmed that a symbiotic relationship exists between internal and external wetting of porous particles whereby each enhances the other. Fu...

2013
WaiChing Sun Matthew R. Kuhn John W. Rudnicki

This paper presents a multiscale analysis of a dilatant shear band using a three-dimensional discrete element method and a lattice Boltzmann/finite element hybrid scheme. In particular, three-dimensional simple shear tests are conducted via the discrete element method. A spatial homogenization is performed to recover the macroscopic stress from the micro-mechanical force chains. The pore geomet...

2006
Feng-Yuan Zhang Ajay K Prasad Suresh G Advani

A new fabrication technique based on etching is employed to convert a copper foil into a porous structure with an array of micron size pores. The motivation stems from the need to develop a more efficient and controllable gas diffusion medium for fuel cell applications. The influence of mask shape, mask width and etching time was investigated experimentally. A correlation to predict trench widt...

The routine measurement of direction-dependent reservoir rock properties like permeability often takes place along the axial direction of core samples. As permeability is a tensor property of porous materials, it should be fully described by a tensor matrix or by three main permeabilities in principal directions. Due to compaction, cementation, and other lithification processes, which take plac...

Journal: :Frontiers in Earth Science 2023

When a sandstone reservoir enters the ultra-high water cut stage, oil phase changes from continuous to discontinuous, which results in difficulties further development and utilization of reservoir. It is important clarify flow law distribution state discontinuous phases guide remaining production. This study selected samples reservoirs, accurately obtained information digital core, constructed ...

2015
Julio C da Silva Kevin Mader Mirko Holler David Haberthür Ana Diaz Manuel Guizar-Sicairos Wu-Cheng Cheng Yuying Shu Jörg Raabe Andreas Menzel Jeroen A van Bokhoven

Porosity in catalyst particles is essential because it enables reactants to reach the active sites and it enables products to leave the catalyst. The engineering of composite-particle catalysts through the tuning of pore-size distribution and connectivity is hampered by the inability to visualize structure and porosity at critical-length scales. Herein, it is shown that the combination of phase...

2009
M. Riad S. Mikhail

Kaolinite supported bimetallic Pt-Sn catalysts were prepared via impregnation technique using different solvents, water, ethanol and acetone. The catalysts were characterized by X-ray diffraction pattern and temperature programmed reduction techniques. Surface area and pore size distribution were determined by nitrogen physisorption technique. The activities of the catalysts were measured towar...

2004
L. Tian M. Holtz

We demonstrate an approach for producing an array of nanopores on a silicon surface. The methods used combine nonlithographic pattern transfer and chlorine plasma etching to produce ,60 nm diam holes up to 1 mm in depth. The near-normal specular optical reflectance of these systematically modified surfaces is found to decrease dramatically with pore depth across the entire 2.0–6.0 eV photon ene...

2017
Xianfeng Zheng Guofang Shen Chao Wang Yu Li Darren Dunphy Tawfique Hasan C. Jeffrey Brinker Bao-Lian Su

Both plants and animals possess analogous tissues containing hierarchical networks of pores, with pore size ratios that have evolved to maximize mass transport and rates of reactions. The underlying physical principles of this optimized hierarchical design are embodied in Murray's law. However, we are yet to realize the benefit of mimicking nature's Murray networks in synthetic materials due to...

Journal: :Small 2012
Jae Hyun Park Weihua Guan Mark A Reed Predrag S Krstić

A charged microparticle can be trapped in an aqueous environment by forming a narrow virtual pore--a cylindrical space region in which the particle motion in the radial direction is limited by forces emerging from dynamical interactions of the particle charge and dipole moment with an external radiofrequency quadrupole electric field. If the particle satisfies the trap stability criteria, its m...

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