Long-term aging of Ag/a-C:H:O nanocomposite coatings in air and in aqueous environment

In nuclear waste repository design bentonite has been included as part of the backfill for its sorbtive capacity and low water permeability. Nevertheless, it cannot keep the waste form dry once intrusion of groundwater has occured [1]. Leach experiments [2], [3] with the radioactive nuclear waste form borosilicate glass JSS-A have been performed with and without bentonite present to provide a database which allows the long term stability of the glass in aqueous environment to be forecasted and the chemical effects of bentonite to be studied.

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Leached Nuclear Waste Glasses: Ultramicrotomy and AEM Characterization

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100135824 ◽

1990 ◽

Vol 48 (2) ◽

pp. 444-445

Author(s):

J.P. Bradley ◽

J.K. Bates

Keyword(s):

Nuclear Waste ◽

Waste Form ◽

Experimental Program ◽

Nuclear Waste Repository ◽

Aqueous Environment ◽

Borosilicate Glasses ◽

Secondary Phases ◽

Thin Sections ◽

The Stability

The long term performance of a nuclear waste repository depends ultimately on the stability of the waste form. Borosilicate glasses have been proposed as a waste form because they can incorporate radionuclides into their structures and they are relatively resistant to corrosion in an aqueous environment. Experimental and computer modeling programs are in progress to evaluate their long term stability in a geological repository. In the experimental program, glasses have been reacted in sealed vessels (for between 7 and 280 days) to simulate the effects of terrestrial aqueous alteration (leaching). During leaching, a layer of secondary phases (predominantly layer silicates) builds up on the glass surfaces (Pigs. 1-3). Determination of the mineralogy of the leached layer is critical for evaluation of glass performance, but the layers are typically ultra-thin (1-50 μm), poorly crystallized, friable coatings that have eluded detailed characterization. Using ultramicrotomy, we have successfully prepared electron transparent thin-sections of the glasses plus leached layers with minimal disturbance of their indigenous microstructures (Figs. 2-4).

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A novel open-system technique to monitor real-time oxygen consumption during early phases of seed germination

Seed Science Research ◽

10.1079/ssr2003151 ◽

2004 ◽

Vol 14 (1) ◽

pp. 17-26 ◽

Cited By ~ 3

Author(s):

C. Jacyn Baker ◽

Daniel P. Roberts ◽

Norton M. Mock ◽

Vansie L. Blount

Keyword(s):

Oxygen Consumption ◽

Steady State ◽

Seed Germination ◽

Real Time ◽

Oxygen Concentration ◽

Open System ◽

Aqueous Environment ◽

Bathing Solution ◽

Closed Chamber

A novel technique allows long-term monitoring of real-time oxygen consumption during seed germination in an open system. Most current techniques used to detect oxygen consumption by seeds measure the decrease in oxygen concentration in a closed chamber. This is not ideal for long-term experiments because the chamber must be replenished with air periodically, subjecting the seeds to abrupt changes in oxygen concentration. The current technique employs an open system, in which seeds are submerged in a continuously aerated aqueous environment. Oxygen electrodes are used to measure the steady-state concentration of oxygen in the solution, which is a function of both the rate of oxygen consumption by the seed and the rate of aeration from the atmosphere. The rate of aeration is directly dependent on the oxygen concentration of the bathing solution; therefore, previous calibration of the system allows the direct conversion of steady-state oxygen concentrations into oxygen consumption rates. Because oxygen is not limiting, the experimental design described here can monitor the same sample non-intrusively every minute for more than 24 h, allowing for greater precision than hourly readings often reported with current techniques. Multiple treatments and/or replicates can be run simultaneously, allowing sensitive comparison of various seed treatments or seed types. To illustrate its potential application, the technique was used to follow the rehydration and pre-emergence phases of germination of cucumber (Cucumis sativum), pea (Pisum sativum) and mustard (Brassica juncea) seeds, detect the inhibitory effects of surface sterilization techniques on seed respiration of cucumber, and follow the interaction of a bacterial biocontrol agent with germinating cucumber and pea seeds.

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A facile and large-area fabrication method of superhydrophobic self-cleaning fluorinated polysiloxane/TiO2 nanocomposite coatings with long-term durability

Journal of Materials Chemistry ◽

10.1039/c0jm04546b ◽

2011 ◽

Vol 21 (17) ◽

pp. 6161 ◽

Cited By ~ 112

Author(s):

Xiaofeng Ding ◽

Shuxue Zhou ◽

Guangxin Gu ◽

Limin Wu

Keyword(s):

Nanocomposite Coatings ◽

Fabrication Method ◽

Large Area ◽

Self Cleaning

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Effect of Minor Alloying Elements (C, Ni, Cr, Mo) on the Long-Term Corrosion Behaviors of Ultrahigh-Strength Automotive Steel Sheet in Neutral Aqueous Environment

Korean Journal of Metals and Materials ◽

10.3365/kjmm.2022.60.1.35 ◽

2022 ◽

Vol 60 (1) ◽

pp. 35-45

Author(s):

Hye Rin Bang ◽

Jin-seong Park ◽

Hwan Goo Seong ◽

Sung Jin Kim

Keyword(s):

Corrosion Current ◽

Alloying Elements ◽

Aqueous Environment ◽

Beneficial Effects ◽

Steel Sheets ◽

Ultrahigh Strength ◽

Minor Addition ◽

Corrosion Behaviors ◽

Automotive Steel

This study examined the effects of minor alloying elements (C, Ni, Cr, and Mo) on the long-term corrosion behaviors of ultrahigh-strength automotive steel sheets with a tensile strength of more than 1800 MPa. A range of experimental and analytical results showed that the addition of Ni, Cr, and Mo decreased the corrosion current density and weight loss in electrochemical and immersion tests, respectively, in a neutral aqueous condition. This suggests that the minor addition of elements to steel can result in improved corrosion resistance even for long-term immersion periods. This is closely associated with the formation of thin and stable corrosion scale on the surface, which was enriched with the alloying elements (Ni, Cr, and Mo). On the other hand, their beneficial effects did not persist during the prolonged immersion periods in steel with a higher C content, suggesting that the beneficial effects of the minor addition of Ni, Cr, and Mo were overridden by the detrimental effects of a higher C content as the immersion time was increased. Based on these results, lower C and the optimal use of Ni, Cr, and Mo are suggested as a desirable alloy design strategy for developing ultrahigh-strength steel sheets that can be exposed frequently to a neutral aqueous environment.

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PREPARATION AND CHARACTERIZATION OF EDIBLE OIL NANOEMULSIONS FOR ENHANCED STABILITY AND ORAL DELIVERY OF CURCUMIN

International Journal of Applied Pharmaceutics ◽

10.22159/ijap.2018v10i6.28726 ◽

2018 ◽

Vol 10 (6) ◽

pp. 139 ◽

Cited By ~ 2

Author(s):

Jonathan Sampath Franklyne ◽

Abinaya Nadarajan ◽

Andrew Ebenazer ◽

Nisha Tiwari ◽

Amitava Mukherjee ◽

...

Keyword(s):

Olive Oil ◽

Droplet Size ◽

Oral Delivery ◽

Physicochemical Characteristics ◽

Gastric Fluid ◽

Edible Oil ◽

Aqueous Environment ◽

Long Term Stability

Objective: This work aims to improve the oral bioavailability and long-term aqueous stability of curcumin using various edible oil nanoemulsions (NEs).Methods: NEs were optimized using the water titration method. Curcumin was loaded into optimized emulsions, and the physicochemical characteristics were determined. Long-term stability of curcumin in the edible oil NEs was analyzed by determining the droplet size, PDI and curcumin concentrations over 4 mo. Release of curcumin from the NEs was determined using a Franz diffusion apparatus and analysed using 5 mathematical models.Results: The absorbance of curcumin was linear over the concentration range of 1 to 10 μg. ml-1. The LOD and LOQ ranged from 0.57 to 1.26μg. ml-1 and 1.89 to 4.19μg. ml-1 respectively. All the NEs were monodisperse and had a droplet size less than 150 nm. Long-term emulsion stability shows no change in droplet size and PI (Dunnett's multiple comparisons test with a confidence interval of 95%). Olive oil NE showed significantly low release in gastric fluid (9.28%) with a good release (92.99%) in intestinal fluid and 48% in a body fluid by 8 h.Conclusion: The work highlights the use of olive oil NEs as a delivery vehicle for curcumin with excellent release characteristics and the ability to protect curcumin in an aqueous environment.

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