Stability assessment of iron oxide yellow pigment dispersions and temperature dependent implications of rheological measurements

The oxygen isotope composition (δ18O) of marine sedimentary rocks has increased by 10 to 15 per mil since Archean time. Interpretation of this trend is hindered by the dual control of temperature and fluid δ18O on the rocks’ isotopic composition. A new δ18O record in marine iron oxides covering the past ~2000 million years shows a similar secular rise. Iron oxide precipitation experiments reveal a weakly temperature-dependent iron oxide–water oxygen isotope fractionation, suggesting that increasing seawater δ18O over time was the primary cause of the long-term rise in δ18O values of marine precipitates. The18O enrichment may have been driven by an increase in terrestrial sediment cover, a change in the proportion of high- and low-temperature crustal alteration, or a combination of these and other factors.

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Analysis of Fatigue and Healing Properties of Conventional Bitumen and Bio-Binder for Road Pavements

Materials ◽

10.3390/ma13020420 ◽

2020 ◽

Vol 13 (2) ◽

pp. 420 ◽

Cited By ~ 1

Author(s):

Elena Gaudenzi ◽

Fabrizio Cardone ◽

Xiaohu Lu ◽

Francesco Canestrari

Keyword(s):

Experimental Approach ◽

Fatigue Behavior ◽

Self Healing ◽

Aged Condition ◽

Temperature Dependent ◽

Modified Bitumen ◽

Complex Issue ◽

Rheological Measurements ◽

Bio Oil ◽

Bituminous Binders

The analysis of fatigue behavior of bituminous binders is a complex issue due to several time-temperature dependent phenomena which interact simultaneously, such as damage accumulation, viscoelasticity, thixotropy, and healing. The present research involves rheological measurements aimed at evaluating the fatigue behavior and compares the self-healing capability of two plain bitumen and a bio-binder obtained by partially replacing one of the plain bitumen with a renewable bio-oil. Healing potential was assessed by means of an experimental approach previously implemented for modified bitumen and bituminous mastic and based on the use of a dynamic shear rheometer (DSR). The effects of some variables such as bitumen type, bio-oil addition, and aging on the healing potential of binders were taken into account. Results showed that the above-mentioned method for healing analysis is also suitable for conventional and bio-add binders. Outcomes of the experimental investigation highlight that fatigue and self-healing are mainly dependent on binder consistency and also affected by aging. Finally, the addition of bio-oil may induce even better performances in terms of healing potential compared to conventional bitumen, especially in aged condition.

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Some Rheological Measurements on Magnetic Iron Oxide Suspensions in Silicone Oil

Journal of Rheology ◽

10.1122/1.549892 ◽

1986 ◽

Vol 30 (5) ◽

pp. 1015-1029 ◽

Cited By ~ 94

Author(s):

M.‐C. Yang ◽

L. E. Scriven ◽

C. W. Macosko

Keyword(s):

Iron Oxide ◽

Silicone Oil ◽

Magnetic Iron Oxide ◽

Rheological Measurements

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Poly(N-isopropylacrylamide)-Coated Superparamagnetic Iron Oxide Nanoparticles: Relaxometric and Fluorescence Behavior Correlate to Temperature-Dependent Aggregation

Chemistry of Materials ◽

10.1021/cm2009048 ◽

2011 ◽

Vol 23 (14) ◽

pp. 3348-3356 ◽

Cited By ~ 41

Author(s):

Sharavanan Balasubramaniam ◽

Nikorn Pothayee ◽

Yinnian Lin ◽

Mike House ◽

Robert C. Woodward ◽

...

Keyword(s):

Iron Oxide ◽

Iron Oxide Nanoparticles ◽

Superparamagnetic Iron Oxide ◽

Superparamagnetic Iron Oxide Nanoparticles ◽

Oxide Nanoparticles ◽

Temperature Dependent

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Polyacrylic acid pore-filled microporous membranes and their use in membrane-mediated synthesis of nanocrystalline ferrihydrite

Canadian Journal of Chemistry ◽

10.1139/v97-210 ◽

1998 ◽

Vol 76 (1) ◽

pp. 10-17 ◽

Cited By ~ 21

Author(s):

Françoise M Winnik ◽

André Morneau ◽

Alicja M Mika ◽

Ronald F Childs ◽

Anna Roig ◽

...

Keyword(s):

Mössbauer Spectroscopy ◽

Iron Oxide ◽

Acrylic Acid ◽

Mossbauer Spectroscopy ◽

Ferrous Ions ◽

Temperature Dependent ◽

Mößbauer Spectroscopy ◽

Graft Yield ◽

Water Contents ◽

Poly Acrylic Acid

A series of cation-exchange membranes were obtained by photoinitiated grafting of acrylic acid onto a polypropylene microporous support having 0.2 µm diameter pores. The poly(acrylic acid) was shown to be contained within the pores of the membrane. The ion-exchange capacities of these "pore-filled" membranes ranged from 65 to 80% of the theoretical values calculated on the basis of their measured graft yields, with water contents ranging from 72 to 77%. The membranes exhibited a chemical valve effect of flux as a function of pH. Treatment of a poly(acrylic acid) grafted membrane with a solution containing ferrous ions resulted in a large uptake of iron (>24% by weight of iron with a membrane containing 152% graft yield of poly(acrylic acid)). Subsequent alkaline (pH 14) oxidation at 70°C with either oxygen or hydrogen peroxide led to the formation of a superparamagnetic nanocrystalline form of ferrihydrite, 5Fe2O3 ·9H2O. The oxide was identified by temperature-dependent Mössbauer spectroscopy recorded from 300 K to 4.2 K. TEM micrographs of sectioned membranes that were treated with H2O2 revealed the presence of two iron oxide morphologies, disk-shaped particles 3-4 nm in diameter and needle-like particles about 4 nm wide and 50 nm long. Only disk-shaped particles were observed in membranes treated with O2. Magnetization measurements indicate that the membranes are superparamagnetic above 50 K with a room temperature magnetization of 3.3 emu g-1 at 20 kOe.Key words: membrane, poly(acrylic acid); iron oxide, magnetic, Mössbauer spectroscopy; magnetization, photografting.

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