The Impact of Mesopores on Mass Transfer in Nanoporous Materials: Evidence of Diffusion Measurement by NMR

2011 ◽  
Vol 83 (1-2) ◽  
pp. 166-176 ◽  
Author(s):  
Rustem Valiullin ◽  
Jörg Kärger
Keyword(s):  
Mass Transfer ◽  
Nanoporous Materials ◽  
Diffusion Measurement ◽  
The Impact

scholarly journals Diffusion Research with Nanoporous Material

2021 ◽  
Vol 43 (3) ◽  
pp. 25-29
Author(s):  
Jörg Kärger ◽  
Douglas M. Ruthven ◽  
Rustem Valiullin
Keyword(s):  
Experimental Data ◽  
Mass Transfer ◽  
Green Chemistry ◽  
Nanoporous Materials ◽  
Nanoporous Material ◽  
Diffusion Measurement ◽  
Selective Conversion ◽  
Present Feature ◽  
Shape Selective ◽  
Molecular Sieving

Abstract Owing to their potential for eco-friendly matter upgrading by molecular sieving and shape-selective conversion, nanoporous materials are among the pioneers of green chemistry. The performance of their application is often controlled by diffusion, i.e. the rate of mass transfer within these materials. This mass transfer, however, is rather complex and subject to numerous influences. Unambiguous diffusion measurement has thus remained a challenge to this day with errors in the interpretation of experimental data being all too common. The present feature reports the efforts of an IUPAC initiative to overcome these limitations.

scholarly journals Numerical Simulation of Heat Mass Transfer Effects on MHD Flow of Williamson Nanofluid by a Stretching Surface with Thermal Conductivity and Variable Thickness

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 684
Author(s):  
Saeed Islam ◽  
Haroon Ur Rasheed ◽  
Kottakkaran Sooppy Nisar ◽  
Nawal A. Alshehri ◽  
Mohammed Zakarya
Keyword(s):  
Thermal Conductivity ◽  
Boundary Layer ◽  
Mass Transfer ◽  
Differential Equations ◽  
Variable Thickness ◽  
Heat Mass Transfer ◽  
Mathematical Formulation ◽  
Stretching Surface ◽  
Nanofluid Flow ◽  
The Impact

The current analysis deals with radiative aspects of magnetohydrodynamic boundary layer flow with heat mass transfer features on electrically conductive Williamson nanofluid by a stretching surface. The impact of variable thickness and thermal conductivity characteristics in view of melting heat flow are examined. The mathematical formulation of Williamson nanofluid flow is based on boundary layer theory pioneered by Prandtl. The boundary layer nanofluid flow idea yields a constitutive flow laws of partial differential equations (PDEs) are made dimensionless and then reduce to ordinary nonlinear differential equations (ODEs) versus transformation technique. A built-in numerical algorithm bvp4c in Mathematica software is employed for nonlinear systems computation. Considerable features of dimensionless parameters are reviewed via graphical description. A comparison with another homotopic approach (HAM) as a limiting case and an excellent agreement perceived.

A Novel Adsorption Differential Volumetric Apparatus to Measure Mass Transfer in Nanoporous Materials

2021 ◽  
pp. 120210
Author(s):  
Jin-Yu Wang ◽  
Enzo Mangano ◽  
Stefano Brandani ◽  
Federico Brandani ◽  
Pluton Pullumbi
Keyword(s):  
Mass Transfer ◽  
Nanoporous Materials

Role of mesopores in Co/ZSM-5 for the direct synthesis of liquid fuel by Fischer–Tropsch synthesis

2018 ◽  
Vol 8 (24) ◽  
pp. 6346-6359 ◽  
Author(s):  
Ji-Eun Min ◽  
Sungtak Kim ◽  
Geunjae Kwak ◽  
Yong Tae Kim ◽  
Seung Ju Han ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Pore Structure ◽  
Liquid Fuel ◽  
Direct Synthesis ◽  
Reaction System ◽  
Complex Reaction ◽  
Fischer Tropsch ◽  
Solid Catalysts ◽  
The Impact

In a complex reaction system, in which gas, liquid, and solid catalysts work together, understanding the impact of mass transfer that varies with the catalyst pore structure is very challenging but also essential to designing selective catalysts.

Effect of Thermophoresis and Brownian Moment on 2D MHD Nanofluid Flow over an Elongated Sheet

2017 ◽  
Vol 377 ◽  
pp. 111-126 ◽  
Author(s):  
C. Sulochana ◽  
G.P Ashwinkumar ◽  
Naramgari Sandeep
Keyword(s):  
Mass Transfer ◽  
Heat Source ◽  
Heat And Mass Transfer ◽  
Newtonian Fluid ◽  
Numerical Solutions ◽  
Frictional Heating ◽  
Mass Transfer Rate ◽  
Dual Nature ◽  
Source Sink ◽  
The Impact

In this study, we investigated the 2D MHD flow of a dissipative Maxwell nanofluid past an elongated sheet with uneven heat source/sink, Brownian moment and thermophoresis effects. The flow governing PDEs are transmuted into nonlinear ODEs adopting the suitable similarity transmissions. Further, the RK-4 technique is employed to acquire the numerical solutions. The impact of pertinent parameters such as thermal radiation, frictional heating, irregular heat source/sink, biot number, Brownian moment and thermophoresis on the flow quantities such as velocity, thermal and concentration fields likewise friction factor, heat and mass transfer rates are bestowed with the succour of graphs and tables. Dual nature is witnessed for Newtonian and non-Newtonian fluid cases. It is noticed that the heat and mass transfer rate in Newtonian fluid larger as compared with non-Newtonian fluid.

A New Air Dehydration Process for Wood Dryers. Part I. Kinetic and Quality of Drying

Holzforschung ◽  
2000 ◽  
Vol 54 (2) ◽  
pp. 201-206 ◽  
Author(s):  
L. Chrusciel ◽  
E. Mougel ◽  
A. Zoulalian
Keyword(s):  
Mass Transfer ◽  
Low Temperature ◽  
Triethylene Glycol ◽  
Dehydration Process ◽  
Wood Drying ◽  
Drying Kinetic ◽  
Hydrocarbon Gas ◽  
Air Dehydration ◽  
The Impact

Summary In conventional wood dryers, air is dehumidified by condensation or by its partial remove. A new air dehydration process is proposed for low temperature convective wood drying. This process consists in using an absorber working with an organic absorbent, the triethylene glycol (TEG) that is pulverised in a venturi type of device. The adaptation of this process well known for hydrocarbon gas dehydration and its interest for wood drying operations are discussed. The prototype installation is presented and the impact of the absorption on the evolution on drying cycles are investigated. The performances of the absorber are evaluated quantitatively and qualitatively. The average drying kinetic is quantified with a global mass transfer coefficient and the drying quality is characterised through the measurements of defects generated during drying.

The Impact of Metabolic Mass Transfer and Abiotic Resource Dynamics on Microbial Growth

2003 ◽  
Author(s):  
Johnathan J. Vadasz
Keyword(s):  
Mass Transfer ◽  
Inflection Point ◽  
Microbial Growth ◽  
Microbial Population ◽  
Essential Feature ◽  
Food Microbiology ◽  
Lag Phase ◽  
Resource Dynamics ◽  
Abiotic Resource ◽  
The Impact

Accounting for metabolic mass transfer and abiotic resource dynamics is not common in modeling microbial population growth. In this paper it is demonstrated that the latter is an essential feature that needs to be considered if reliable results are sought. The results of a model that takes the metabolic mass transfer and abiotic resource dynamics into account are shown to capture a variety of features that appear in experiments such as a Lag phase, a Logarithmic Inflection Point, growth followed by decline and oscillations. The results have a wide variety of implications and applications, from food microbiology and wine fermentation, up to human cell growth, where the latter includes tumor growth.

Influence of Non-Newtonian Rheology on Mass Transfer From a Biofluid in Separated and Reattached Flows

2018 ◽  
Author(s):  
Khaled J. Hammad
Keyword(s):  
Mass Transfer ◽  
Yield Stress ◽  
Mass Transfer Rate ◽  
Flow Region ◽  
Shear Thinning ◽  
Recirculation Region ◽  
Transfer Rates ◽  
Separated And Reattached Flow ◽  
The Impact ◽  
Wall Mass

Influence of the rheological model selection on the flow and mass transfer behavior of human blood in a separated and reattached flow region is investigated. Newtonian and non-Newtonian hemorheological models that account for the yield stress and shear-thinning characteristics of blood are used. The conservation of mass, momentum, and species equations as well as the Herschel-Bulkley constitutive equation are solved numerically using a finite-difference scheme. A parametric study is performed to reveal the impact of flow restriction and rheological modelling on blood-borne oxygen exchange with the confining walls. The wall mass transfer rates within the separated and reattached regions display a strong dependency on the used hemorheological model. Newtonian and non-Newtonian models result in a peak wall mass transfer rate within the recirculation region. However, non-Newtonian models that account for the yield stress and shear-thinning effects predict a substantial, highly localized, drop in the wall mass transfer rates of oxygen, at the reattachment point.

scholarly journals The human impact on North American erosion, sediment transfer, and storage in a geologic context

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
David B. Kemp ◽  
Peter M. Sadler ◽  
Veerle Vanacker
Keyword(s):  
Mass Transfer ◽  
North American ◽  
Sediment Accumulation ◽  
River System ◽  
Rapid Expansion ◽  
Past Century ◽  
Spatial And Temporal Scales ◽  
Alluvial Sediment ◽  
European Colonization ◽  
The Impact

AbstractHumans are primary agents of geomorphic change, and rates of anthropogenic landscape change likely far exceed the pace of change expected from natural geologic processes. Nevertheless, our understanding of the impact of humans on the natural landscape is limited by difficulties in accurately comparing past and present rates of change across wide spatial and temporal scales. Here, we present a compilation of  >4000 rates of alluvial sediment accumulation that provide an indirect record of North American erosion, mass transfer and sediment storage from the late Pleistocene to the present day. Continent-wide rates of alluvium accumulation were broadly stable for ~40,000 years, but increased 10-fold during the rapid expansion of agriculture and river system modification associated with European colonization. Interpreted in terms of mass transfer, humans have moved as much sediment in North America in the past century as natural processes can transfer in 700–3000 years.

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