R7T7 Nuclear Waste Glass Behavior in Moist Clay: Role of the Clay Mass/Glass Surface Area Ratio

1989 ◽  
Vol 176 ◽  
Author(s):  
N. Godon ◽  
E. Vernaz
Keyword(s):  
Corrosion Rate ◽  
Surface Area ◽  
Glass Surface ◽  
Retention Factor ◽  
Distilled Water ◽  
Barrier Material ◽  
Surface Area Ratio ◽  
Corrosion Rates ◽  
Glass Corrosion

ABSTRACTR7T7 glass alteration was investigated in the presence of various moist clays. In contact with smectite 4a, selected in France as a potential engineered barrier material, the glass was significantly corroded: after 6 months the glass corrosion rate was practically the same as the initial alteration rate in double-distilled water. Substantially lower alteration was observed in contact with bentonite 6 activated by sodium carbonate.Smectite 4a consumes silicon released by glass corrosion, and thus retards the rise to high silicon concentrations in solution at which the glass corrosion rate diminishes. Glass can therefore in some cases be altered as much in moist clay as in water with high renewal rates. Other experiments with smaller quantities of smectite 4a showed that the phenomenon becomes less important in time: its duration is proportional to the ratio between the clay mass (C) and the glass surface area (SA). Comparing the results of studies at different C/SA ratios indicates that low glass corrosion rates are obtained more slowly at higher C/SA ratios.Tests with 239Pu-doped R7T7 glass also showed that the radionuclide retention factor in the alteration film at the glass surface is only 6, compared with a factor of nearly 50 in double-distilled water.

Corrosion Inhibition Enhancement for Surface O&G Operations Using Nanofluids

2021 ◽  
Author(s):  
Camilo Mazo ◽  
Daniel Lopez ◽  
Angela Marcela Forero ◽  
Andres Maya ◽  
Miguel Lesmes ◽  
...  
Keyword(s):  
Corrosion Rate ◽  
Corrosion Inhibitor ◽  
Oil And Gas ◽  
Strong Acid ◽  
Carbon Quantum Dots ◽  
Metallic Surface ◽  
Acid Media ◽  
Corrosion Rates ◽  
Synergistic Behavior

Abstract The main objective of this study is to develop and evaluate a nanotechnology-based material in combination with a commercial corrosion inhibitor (CI) as an alternative to reduce the corrosion rate in oil and gas facilities. The corrosion rate (CR) of surface facilities coupons was estimated using weight loss analysis as the response variable in the following study, showing that in absence of CI treatments, carbon steel (CS) coupon displays corrosion rates over 2.1 mm·y−1. Four commercial CI were evaluated at concentrations ranging between 35-50 mg·L−1 to select the most suitable treatment at surface facilities conditions, showing CR reductions of around 12.2 and 22.5% in both dosages for the best CI treatment. SiO2 and Carbon Quantum Dots (CQDs) nanomaterials were added to the selected CI at nanoparticle dosages from 50 to 500 mg·L−1 to improve the behavior of the selected treatment in presence of production brine. The effectiveness of the proposed nanomaterials is strongly dependent on the nanoparticle concentration, and hence, its dispersion degree onto the metallic surface, whereas low dosages in SiO2 lead to an increase in the CR, however, low dosages in CQD lead to a reduction of the CR. The proposed NanoIC was evaluated using 1M HCl solutions to study the role of the nanoparticles in strong acid media. The corrosion rates for CS outcrops in the presence of production brine with 1M HCl was 8.6 mm·y−1, which suggests an important role of mineral acids in the corrosion phenomena. In the presence of CI at a dosage of 35 mg·L−1, the corrosion rate was reduced by 10.7%. The CR of CS surfaces treated with brine and strong acid solutions in presence of NanoCI containing CQD nanomaterials at 50 mg·L−1 shows reductions of 28.6 and 74.2%, respectively. It can be concluded, the nanoparticles act as a corrosion inhibitor agent, reducing the interaction between the acid molecules and the steel surface by the formation of a thin film. This work opens the landscape into the incorporation of carbon-based nanomaterials in surface oil and gas operations for the reduction of the corrosion rate in the facilities during the production stage in the wells by the synergistic behavior between commercial corrosion inhibitor and nanoparticles.

The formation of desilication products in the presence of kaolinite and halloysite – The role of surface area

2021 ◽  
pp. 105643
Author(s):  
Jose F. Gomes ◽  
Michael Davies ◽  
Peter Smith ◽  
Franca Jones
Keyword(s):  
Surface Area

Elucidating the Origin of the Toxicity of Nano-CeO2 to Chlorella pyrenoidosa：the Role of Specific Surface Area and Chemical Composition

2021 ◽  
Author(s):  
Changjian Xie ◽  
Yuhui Ma ◽  
Peng Zhang ◽  
Junzhe Zhang ◽  
Xiaowei Li ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Aquatic Environment ◽  
Cerium Dioxide ◽  
Environmental Application ◽  
Ecotoxicological Effects

With the increasing environmental application and discharge of nano cerium dioxide (nano-CeO2), it is urgent to fully understand its ecotoxicological effects on the aquatic environment. This study for the first...

Effect of Undernutrition During the Perinatal Period on Caries Development in the Rat: II. Caries Susceptibility in Underfed Rats Supplemented with Protein or Caloric Additions During the Suckling Period

1973 ◽  
Vol 52 (4) ◽  
pp. 680-687 ◽  
Author(s):  
Lewis Menaker ◽  
Juan M. Navia
Keyword(s):  
Dental Caries ◽  
Perinatal Period ◽  
Protein Deficiency ◽  
Specific Role ◽  
Protein Supplement ◽  
Distilled Water ◽  
Suckling Period ◽  
Rat Pups ◽  
Low Incidence

The specific role of protein deficiency in altering dental caries incidence in rat pups was investigated. A 10% protein supplement given to undernourished rats during development allowed them to overcome weight deficiencies and reversed dental caries to the low incidence found in well-nourished control rats. Caries in undernourished rats supplemented with an isocaloric, proteinfree solution, was as high as that of undernourished rats intubated with distilled water.

scholarly journals Engineering Mesoporous NiO with Enriched Electrophilic Ni3+ and O− toward Efficient Oxygen Evolution

Catalysts ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 310 ◽  
Author(s):  
Xiu Liu ◽  
Zhi-Yuan Zhai ◽  
Zhou Chen ◽  
Li-Zhong Zhang ◽  
Xiu-Feng Zhao ◽  
...  
Keyword(s):  
Surface Area ◽  
Oxygen Evolution ◽  
Low Cost ◽  
Large Surface Area ◽  
Nucleophilic Attack ◽  
Title Reaction ◽  
Highly Active ◽  
Decomposition Of Water ◽  
Uniform Mesopores

Tremendous efforts have been devoted to develop low-cost and highly active electrocatalysts for oxygen evolution reaction (OER). Here, we report the synthesis of mesoporous nickel oxide by the template method and its application in the title reaction. The as-prepared mesoporous NiO possesses a large surface area, uniform mesopores, and rich surface electrophilic Ni3+ and O− species. The overpotential of meso-NiO in alkaline medium is 132 mV at 10 mA cm−1 and 410 mV at 50 mA cm−1, which is much smaller than that of the other types of NiO samples. The improvement in the OER activity can be ascribed to the synergy of the large surface area and uniform mesopores for better mass transfer and high density of Ni3+ and O− species favoring the nucleophilic attack by OH− to form a NiOOH intermediate. The reaction process and the role of electrophilic Ni3+ and O− were discussed in detail. This results are more conducive to the electrochemical decomposition of water to produce hydrogen fuel as a clean and renewable energy.

scholarly journals Effect of Aging on the Cornea of Male Albino Rat and Possible Therapeutic Role of Royal Jelly

QJM ◽  
2020 ◽  
Vol 113 (Supplement_1) ◽  
Author(s):  
H R Elareny ◽  
A I Ahmed ◽  
A F Alneklawy ◽  
M K Tawfik
Keyword(s):  
Royal Jelly ◽  
Male Rats ◽  
Distilled Water ◽  
Oral Gavage ◽  
Albino Rat ◽  
Therapeutic Role ◽  
Once Daily ◽  
Group I ◽  
Group Ii

Abstract Introduction Nowadays interest in aging has greatly increased, Aging is a complex natural process involving every molecule, cell, and organ in the body that is associated with tissue dysfunction in many organs. Aging of the cornea causes major eye effects and leads to substantial cost in medical and social terms. These effects include the highly prevalent dry eye disease (DED) that affects both visual function and quality of life in elderly. Symptoms of (DED) include, ocular pain, visual disturbances, and increase lacrimation. Functional foods such as Royal jelly (RJ) have a growing attention because of consumers increasing concerns about their health. Its importance not only for its nutritional properties but also for its functional and biological properties such as antioxidant, anti-inflammatory, antibacterial, antiviral, and anti-ulcerous activities. It is used as a cheap natural source in daily life and medicine. (RJ) is a complex substance composed of proteins, sugars, lipids, amino acids, vitamins, and minerals. Aim The present study aimed to investigate the histological effect of aging on the cornea of male albino rat and possible therapeutic role of (RJ) on senile group. Materials and Methods Twenty-four male albino rats were used in this study divided into Group I: consisted of 6 adult male rats aged 3- 6 months. Group II: consisted of 18 senile male rats aged 18-24 months, were further subdivided into three subgroups as follows: Group II A: (n = 6) negative control senile rats, not subjected to any procedure for 4 weeks. Group II B: (n = 6) control senile rats and were given distilled water by oral gavage once daily for 4 weeks. Group II C: (n = 6) senile rats were given (RJ) by oral gavage dissolved in distilled water once daily for 4 weeks. At the end of the experiment, rats were sacrificed after being deeply anesthetized with ether according to the protocol of the Committee of Animal Research Ethics (CARE). The cornea of each animal was carefully dissected out after death and immediately fixed in 10% formalin for preparation of paraffin blocks 5 micrometer thickness. Sections were stained with hematoxylin and eosin (I-I&E), Masson's trichrome and periodic acid-Schiff (PAS). Statistical analysis and quantitative morphometric study were done. Results Light microscopic examination of corneas of senile rats revealed different pathological changes included irregularity in the surface epithelium as well as surface erosions and cytoplasmic vacuolations. The stroma showed widely separated collagen fibers with decreased keratocyte density. It was concluded that (RJ) supplementation to senile rats obviously unproved all layers of the cornea histologically.

The important role of surface area in the electrochemical behaviour of RuO2 electrodes

1977 ◽  
Vol 81 (2) ◽  
pp. 391-394 ◽  
Author(s):  
Laurence D. Burke ◽  
Oliver J. Murphy ◽  
John F. O'Neill
Keyword(s):  
Surface Area ◽  
Electrochemical Behaviour

The Corrosion of Carbon Steel and Stainless Steel in Simulated Geothermal Media

1985 ◽  
Vol 38 (8) ◽  
pp. 1133 ◽  
Author(s):  
BG Pound ◽  
MH Abdurrahman ◽  
MP Glucina ◽  
GA Wright ◽  
RM Sharp
Keyword(s):  
Carbon Steel ◽  
Corrosion Rate ◽  
Stainless Steels ◽  
Polarization Resistance ◽  
Iron Sulfide ◽  
Low Carbon Steel ◽  
Passive Films ◽  
Low Carbon ◽  
Corrosion Rates ◽  
Good Agreement

The corrosion rates of low-carbon steel, and 304, 316 and 410/420 stainless steels in simulated geothermal media containing hydrogen sulfide have been measured by means of the polarization resistance technique. Good agreement was found between weight-loss and polarization resistance measurements of the corrosion rate for all the metals tested. Carbon steel formed a non-adherent film of mackinawite (Fe1 + xS). The lack of protection afforded to the steel by the film resulted in an approximately constant corrosion rate. The stainless steels also exhibited corrosion rates that were independent of time. However, the 410 and 420 alloys formed an adherent film consisting mainly of troilite ( FeS ) which provided only limited passivity. In contrast, the 304 and 316 alloys appeared to be essentially protected by a passive film which did not seem to involve an iron sulfide phase. However, all the stainless steels, particularly the 410 and 420 alloys, showed pitting, which indicated that some breakdown of the passive films occurred.

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