A kinetic model for dissolution of metals — The role of heterogeneous reaction and mass transfer

1993 ◽  
Vol 10 (3) ◽  
pp. 128-134 ◽  
Author(s):  
X. Meng ◽  
K. N. Han
Keyword(s):  
Mass Transfer ◽  
Kinetic Model ◽  
Heterogeneous Reaction

ROLE OF FLOW AND MASS TRANSFER IN PHOTOBIOREACTOR: FROM BACTERIA LOCOMOTION TO HYDROGEN PRODUCTION

2018 ◽  
Author(s):  
Xun Zhu ◽  
Qiang Liao ◽  
Rong Chen ◽  
Ao Xia ◽  
Chao Zhang ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Hydrogen Production

The role of (bio)surfactant sorption in promoting the bioavailability of nutrients localized at the solid-water interface

1999 ◽  
Vol 39 (7) ◽  
pp. 91-98 ◽  
Author(s):  
Ryan N. Jordan ◽  
Eric P. Nichols ◽  
Alfred B. Cunningham
Keyword(s):  
Mass Transfer ◽  
Cell Membrane ◽  
Substrate Concentration ◽  
Water Interface ◽  
Industrial Systems ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
Surfactant Sorption

Bioavailability is herein defined as the accessibility of a substrate by a microorganism. Further, bioavailability is governed by (1) the substrate concentration that the cell membrane “sees,” (i.e., the “directly bioavailable” pool) as well as (2) the rate of mass transfer from potentially bioavailable (e.g., nonaqueous) phases to the directly bioavailable (e.g., aqueous) phase. Mechanisms by which sorbed (bio)surfactants influence these two processes are discussed. We propose the hypothesis that the sorption of (bio)surfactants at the solid-liquid interface is partially responsible for the increased bioavailability of surface-bound nutrients, and offer this as a basis for suggesting the development of engineered in-situ bioremediation technologies that take advantage of low (bio)surfactant concentrations. In addition, other industrial systems where bioavailability phenomena should be considered are addressed.

Kinetic Aspects of the Interplay of Cancer and the Immune System

2019 ◽  
Vol 14 (02) ◽  
pp. 101-114 ◽  
Author(s):  
Vladimir P. Zhdanov
Keyword(s):  
Stem Cells ◽  
Immune System ◽  
Kinetic Model ◽  
Human Population ◽  
Lifetime Risk ◽  
Risk Of Cancer

The understanding of the interplay between cancer and the immune system is still limited. Herein, I focus on two aspects of this interplay. First, I propose a kinetic model describing the likely role of the immune system in the lifetime risk of cancer at the level of the whole human population. For each tissue, the risk is predicted to be influenced by the heterogeneity of the population and to depend exponentially on time. The expression for the risk does not, however, depend explicitly on the total number of divisions of the corresponding stem cells. For this reason, the correlation with the latter number can only be indirect. Second, using another kinetic framework, I describe how the growth of a few tumors can depend on their interaction via the immune system. The analysis shows that depending on specific details, the tumors of different sizes tend either to reach the same size or remain to be of different sizes.

Role of nanomaterial's as adsorbent for heterogeneous reaction in waste water treatment

2021 ◽  
pp. 130596
Author(s):  
M. Sridevi ◽  
C. Nirmala ◽  
N. Jawahar ◽  
G. Arthi ◽  
Sugumari Vallinayagam ◽  
...  
Keyword(s):  
Waste Water ◽  
Water Treatment ◽  
Heterogeneous Reaction ◽  
Waste Water Treatment

scholarly journals Carbothermic Reduction of Zinc Containing Industrial Wastes: A Kinetic Model

2021 ◽  
Author(s):  
M. Leuchtenmueller ◽  
C. Legerer ◽  
U. Brandner ◽  
J. Antrekowitsch
Keyword(s):  
Mass Transfer ◽  
Zinc Oxide ◽  
Kinetic Model ◽  
Large Scale ◽  
Industrial Wastes ◽  
Oxide Reduction ◽  
Transfer Coefficients ◽  
Metallothermic Reduction ◽  
Metal Bath ◽  
Zinc Recovery

AbstractEffective recycling of zinc-containing industrial wastes, most importantly electric arc furnace dust, is of tremendous importance for the circular economy of the steel and zinc industry. Herein, we propose a comprehensive kinetic model of the combined carbothermic and metallothermic reduction of zinc oxide in a metal bath process. Pyro-metallurgical, large-scale lab experiments of a carbon-saturated iron melt as reduction agent for a molten zinc oxide slag were performed to determine reaction constants and accurately predict mass transfer coefficients of the proposed kinetic model. An experimentally determined kinetic model demonstrates that various reactions run simultaneously during the reduction of zinc oxide and iron oxide. For the investigated slag composition, the temperature-dependent contribution of the metallothermic zinc oxide reduction was between 25 and 50 pct of the overall reaction mechanism. The mass transfer coefficient of the zinc oxide reduction quadrupled from 1400 °C to 1500 °C. The zinc recovery rate was > 99.9 pct in all experiments.

Consecutive reactions: role of mass transfer factors

1974 ◽  
Vol 29 (2) ◽  
pp. 561-569 ◽  
Author(s):  
V.G. Pangarkar ◽  
M.M. Sharma
Keyword(s):  
Mass Transfer ◽  
Transfer Factors ◽  
Consecutive Reactions

Impact of non-thermal electrons on spatial damping: a kinetic model for the parallel propagating modes

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Muhammad Sarfraz ◽  
Gohar Abbas ◽  
Hashim Farooq ◽  
I. Zeba
Keyword(s):  
Kinetic Model ◽  
Wave Spectrum ◽  
Field Approximation ◽  
Weak Field ◽  
Distribution Functions ◽  
Global Perspective ◽  
Energetic Electrons ◽  
Thermal Anisotropy ◽  
Spatial Damping

Abstract A sequence of in situ measurements points the presence of non-thermal species in the profile of particle distributions. This study highlights the role of such energetic electrons on the wave-spectrum. Using Vlasov–Maxwell’s model, the dispersion relations of the parallel propagating modes along with the space scale of damping are discussed using non-relativistic bi-Maxwellian and bi-Kappa distribution functions under the weak field approximation, i.e., ω − k . v > Ω 0 $\left\vert \omega -\mathbf{k}.\mathbf{v}\right\vert { >}{{\Omega}}_{0}$ . Power series and asymptotic expansions of plasma dispersion functions are performed to derive the modes and spatial damping of waves, respectively. The role of these highly energetic electrons is illustrated on real frequency and anomalous damping of R and L-modes which is in fact controlled by the parameter κ in the dispersion. Further, we uncovered the effect of external magnetic field and thermal anisotropy on such spatial attenuation. In global perspective of the kinetic model, it may be another step.

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