Surface-Controlled Reactivity of Metal Carbonates

1996 ◽  
Vol 432 ◽  
Author(s):  
P. V. Brady
Keyword(s):  
Fluid Flow ◽  
Surface Chemistry ◽  
Crystal Nucleation ◽  
Metal Sorption ◽  
Common Component ◽  
Metal Carbonates ◽  
Metal Carbonate ◽  
Control Growth ◽  
Engineered Structures

AbstractMetal carbonate surfaces are a common component of soils, sediments, terrestrial organisms, and many engineered structures. The surface-controlled growth and dissolution of metal carbonate minerals (e.g. calcite) often affects fluid flow in pipes (through scaling) as well as the nanoscale assembly of complex biologic structures (similar reactions control Ca levels in the oceans, and ultimately, long-term CO2 levels). Engineering metal carbonate surface chemistry to enhance or inhibit growth, dissolution, or crystal nucleation is therefore an area with obvious economic impact. Metal carbonate superstructures are rapidly altered by dissolution/re-precipitation reactions, necessitating the measurement of surface chemistry near equilibrium. Measurements of metal sorption using limited residence time reactors point to the importance of adsorbed/exchanged metal ions in controlling surface charge and electrokinetic behavior. The same reactions appear to control growth and dissolution rates as well.

scholarly journals Nitrite Toxicity to Danio rerio: Effects of Subchronic Exposure on Fish Growth

2008 ◽  
Vol 77 (3) ◽  
pp. 455-460 ◽  
Author(s):  
E. Voslářová ◽  
V. Pištěková ◽  
Z. Svobodová ◽  
I. Bedáňová
Keyword(s):  
Danio Rerio ◽  
Significant Inhibition ◽  
Fish Growth ◽  
Long Term Effects ◽  
Exponential Relationship ◽  
Subchronic Exposure ◽  
Control Growth ◽  
Nitrite Toxicity ◽  
Fish Weight

The aim of this study was to investigate the long-term effects of subchronic exposure to sublethal levels of nitrite, ranging from 15 to 130 mg l-1 NO2-, on growth in aquarium fish Danio rerio. The juvenile growth test according to OECD 215 was used in the experiments. Fish weight was measured at the beginning of the experiment and then using the same method, fish weight was observed 28 days after fish stocking. Compared to the control, growth suppression was detected from the concentration of 73 mg l-1 NO2- (P < 0.05) and a significant inhibition of fish body growth was shown from 130 mg l-1 NO2- (P < 0.01). An exponential relationship between nitrite concentrations and specific growth rate (R2 = 0.896) was detected.

Tracing Fluid Flow in Flooded Chalk under Long Term Test Conditions

2013 ◽  
Author(s):  
R.I. Korsnes ◽  
U. Zimmermann ◽  
M.V. Madland ◽  
S.A.R. Bertolino ◽  
T. Hildebrand-Habel ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Test Conditions

scholarly journals Evolution of Fracture Aperture in Quartz Sandstone under Hydrothermal Conditions: Mechanical and Chemical Effects

Minerals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 657
Author(s):  
Chaojie Cheng ◽  
Harald Milsch
Keyword(s):  
Fluid Flow ◽  
Hydraulic Fracture ◽  
Chemical Equilibrium ◽  
Pore Fluid ◽  
Pressure Solution ◽  
Fracture Aperture ◽  
Hydraulic Aperture ◽  
Mechanical Aperture ◽  
Stagnant Flow

Fractures efficiently affect fluid flow in geological formations, and thereby determine mass and energy transport in reservoirs, which are not least exploited for economic resources. In this context, their response to mechanical and thermal changes, as well as fluid–rock interactions, is of paramount importance. In this study, a two-stage flow-through experiment was conducted on a pure quartz sandstone core of low matrix permeability, containing one single macroscopic tensile fracture. In the first short-term stage, the effects of mechanical and hydraulic aperture on pressure and temperature cycles were investigated. The purpose of the subsequent intermittent-flow long-term (140 days) stage was to constrain the evolution of the geometrical and hydraulic fracture properties resulting from pressure solution. Deionized water was used as the pore fluid, and permeability, as well as the effluent Si concentrations, were systematically measured. Overall, hydraulic aperture was shown to be significantly less affected by pressure, temperature and time, in comparison to mechanical aperture. During the long-term part of the experiment at 140 °C, the effluent Si concentrations likely reached a chemical equilibrium state within less than 8 days of stagnant flow, and exceeded the corresponding hydrostatic quartz solubility at this temperature. This implies that the pressure solution was active at the contacting fracture asperities, both at 140 °C and after cooling to 33 °C. The higher temperature yielded a higher dissolution rate and, consequently, a faster attainment of chemical equilibrium within the contact fluid. X-ray µCT observations evidenced a noticeable increase in fracture contact area ratio, which, in combination with theoretical considerations, implies a significant decrease in mechanical aperture. In contrast, the sample permeability, and thus the hydraulic fracture aperture, virtually did not vary. In conclusion, pressure solution-induced fracture aperture changes are affected by the degree of time-dependent variations in pore fluid composition. In contrast to the present case of a quasi-closed system with mostly stagnant flow, in an open system with continuous once-through fluid flow, the activity of the pressure solution may be amplified due to the persistent fluid-chemical nonequilibrium state, thus possibly enhancing aperture and fracture permeability changes.

scholarly journals Effect of Surface Chemistry and Associated Protein Corona on the Long-Term Biodegradation of Iron Oxide Nanoparticles In Vivo

2018 ◽  
Vol 10 (5) ◽  
pp. 4548-4560 ◽  
Author(s):  
Grazyna Stepien ◽  
María Moros ◽  
Marta Pérez-Hernández ◽  
Marta Monge ◽  
Lucía Gutiérrez ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Surface Chemistry ◽  
Iron Oxide Nanoparticles ◽  
Protein Corona ◽  
Oxide Nanoparticles ◽  
Effect Of Surface

Sediment mobilization deposits from episodic subsurface fluid flow—A new tool to reveal long-term earthquake records?

Geology ◽  
2016 ◽  
Vol 44 (4) ◽  
pp. 243-246 ◽  
Author(s):  
A. Reusch ◽  
J. Moernaut ◽  
F.S. Anselmetti ◽  
M. Strasser
Keyword(s):  
Fluid Flow ◽  
Earthquake Records ◽  
Subsurface Fluid ◽  
Sediment Mobilization

Long-term (13 years) measurements of SO2 fluxes over a forest and their control by surface chemistry

2011 ◽  
Vol 151 (12) ◽  
pp. 1768-1780 ◽  
Author(s):  
J. Neirynck ◽  
C.R. Flechard ◽  
D. Fowler
Keyword(s):  
Surface Chemistry

Effect of plastic fragments on hydraulic characteristics of pretreated municipal solid waste

2006 ◽  
Vol 43 (12) ◽  
pp. 1333-1343 ◽  
Author(s):  
Mingliang Xie ◽  
Dirk Aldenkortt ◽  
Jean-Frank Wagner ◽  
Gerhard Rettenberger
Keyword(s):  
Fluid Flow ◽  
Hydraulic Conductivity ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Conceptual Model ◽  
Hydraulic Properties ◽  
Thin Sheet ◽  
Biological Pretreatment ◽  
Soil Material

A systematic study was undertaken of the granular composition and hydraulic properties of municipal solid waste (MSW) produced by mechanical–biological pretreatment (MBP–MSW) from three different treatment plants with the aim of evaluating the potential application of MBP–MSW as an alternative barrier material for landfill final cover systems. Despite its coarse granular composition, MBP–MSW has low hydraulic conductivity. Long-term permeability tests show that the hydraulic conductivity decreases with time. The most likely explanation for the long-term changes in permeability is the swelling of organic material contained within the compost. In the case of saturated flow, the virtually impermeable plastic fragments embedded in the material impede fluid flow. In the unsaturated case, such fragments slow down the drying process by disrupting fluid flow and allowing pooling of water above horizontally oriented fragments. The larger the number and size of the plastic fragments, the greater the influence on hydraulic conductivity and shrinkage. These processes can be better understood with the newly developed conceptual model, the thin-sheet model. Based on this conceptual model, laboratory tests were undertaken to compare natural soil material with mixtures of soil material and plastic fragments. Corresponding numerical simulations of some experiments verified the influence of plastic fragments on the hydraulic properties of MBP–MSW.Key words: mechanical–biological pretreatment, municipal solid waste (MSW), thin-sheet model, plastic fragment, hydraulic conductivity, drying test.

Polygonal fault systems on the mid-Norwegian margin: a long-term source for fluid flow

2003 ◽  
Vol 216 (1) ◽  
pp. 283-290 ◽  
Author(s):  
Christian Berndt ◽  
Stefan Bünz ◽  
Jürgen Mienert
Keyword(s):  
Fluid Flow ◽  
Fault Systems ◽  
Norwegian Margin ◽  
Polygonal Fault
Sign in / Sign up

Export Citation Format

Share Document