Estimating the Throwing Power of SS316 when Coupled with AA7075 Through Finite Element Modeling

CORROSION ◽  
10.5006/3438 ◽  
2020 ◽  
Vol 76 (5) ◽  
pp. 476-484
Author(s):  
R.S. Marshall ◽  
A. Goff ◽  
C. Sprinkle ◽  
A. Britos ◽  
R.G. Kelly
Keyword(s):  
Surface Area ◽  
Noble Metal ◽  
Galvanic Corrosion ◽  
Sol Gel ◽  
Total Surface Area ◽  
Electrochemical Kinetics ◽  
Throwing Power ◽  
Galvanic Current ◽  
Fastener Hole ◽  
The Impact

Galvanic corrosion is common in applications involving a fastener and panel assembly. Often, the fastener is made from a more noble metal and the panel is made from a less noble metal, selected for their respective mechanical properties. The ability for the more noble material to galvanically couple to the panel’s surface as a function of distance is referenced to as “throwing power,” and was the main subject of this research. In this work, SS316 and AA7075 were investigated as the fastener and panel material, respectively. A Ti-6Al-4V fastener and a sol-gel coated SS316 fastener were also considered to determine the impact of different materials on the galvanically driven throwing power. Along with different fastener materials, different fastener geometries were considered as well. Raised fasteners are generally used in tandem with washers, while countersunk fasteners are not in order to remain flush with the surface. The difference between these two geometries on the throwing power was investigated. It was determined that the SS316 washer was the largest contributor to the galvanic current in the raised fastener assembly, due to its large surface area. At distances of two inches away, the SS316 fastener and washer were able to double the natural corrosion rate of AA7075. A countersunk SS316 fastener, with the same total surface area as that of the raised fastener and washer assembly, was seen to lower the throwing power which forced a large amount of current down the fastener hole. Throughout all of the computational tests, the model relies on the generation of accurate electrochemical kinetics measured in solutions of appropriate composition.

Preparation of a Silicon Oximide Gel via a Non-Aqueous Sol-Gel Route

2002 ◽  
Vol 726 ◽  
Author(s):  
Fei Cheng ◽  
John S. Bradley
Keyword(s):  
Amorphous Silicon ◽  
Surface Area ◽  
Sol Gel ◽  
Total Surface Area ◽  
Mas Nmr ◽  
Bet Surface Area ◽  
Molar Ratio ◽  
Microporous Structure ◽  
Silicon Oxycarbonitride ◽  
Cp Mas Nmr

AbstractA silicon oximide gel was prepared by a reaction in N,N-dimethylformamide between tris(dimethylamino)silylamine (Me2N)3SiNH2 (TDSA) and formamide in a 1:2 molar ratio at 50C. The 29Si, 13C CP-MAS NMR and IR analyses indicated that the gel mainly comprised oximino silicon networks [SiOC(H)=NSi]x. The gel exhibited a microporous structure and had a total surface area of 339 m2/g. A microporous structure with a BET surface area of 195 m2/g was also obtained after pyrolysis of the gel at 1000°C for 2 h. Pyrolysis of the gel under N2 up to 1485°C gave an amorphous silicon oxycarbonitride glass.

scholarly journals A Study of Galvanic Corrosion in Stagnant Ammonium Bisulfide Solution

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
H. A. Al-Mazeedi ◽  
A. Al-Farhan ◽  
N. Tanoli ◽  
L. Abraham
Keyword(s):  
Carbon Steel ◽  
Galvanic Corrosion ◽  
Electrochemical Techniques ◽  
Reaction Rates ◽  
Cathodic Reaction ◽  
Galvanic Coupling ◽  
Galvanic Current ◽  
Galvanic Couple ◽  
The Impact ◽  
Incoloy 825

Galvanic corrosion of carbon steel (CS) coupled to four different alloys, namely, 316 SS, 321 SS, Incoloy 825, and 2205 SS, was studied in deaerated 3.5% ammonium bisulfide solution (ABS) at 60°C by electrochemical techniques under stagnant condition. The electrochemical work included the measurements of the potential of separate alloys as well as the measurements of galvanic potential and galvanic current as a function of time and Evans (polarization) diagrams of coupled metals. The impact of galvanic coupling on the anodic and cathodic reaction rates was determined. It was found that the CS suffered galvanic corrosion when it was coupled to all of the selected alloys but at different rates; so, it is recommended to avoid the galvanic coupling of CS with any of the noble alloys in stagnant deaerated 3.5% ABS at 60°C. Results indicated that the best alloy to be used with the CS in stagnant deaerated 3.5% ABS solution at 60°C is SS 2205 since the galvanic couple has the lowest CR with a less negative Ecorr value, indicating that CS corrodes at a lower rate when it is coupled to SS2205 in this environment.

Sol-Gel Synthesis of Novel Silica Hybrid Xerogels: Porous Studies

2013 ◽  
Vol 594-595 ◽  
pp. 1003-1008
Author(s):  
S.A. Syed Nuzul Fadzli ◽  
S. Roslinda ◽  
Radiman Shahidan ◽  
Z. Firuz
Keyword(s):  
Sodium Alginate ◽  
Surface Area ◽  
Calcium Oxide ◽  
Sol Gel ◽  
Mesoporous Structure ◽  
Total Surface Area ◽  
Silica Xerogel ◽  
Silica Xerogels ◽  
Hybrid Silica ◽  
Hybrid Xerogels

Hybrid silica xerogel mesoporous composite was synthesized by a low temperature acid catalysed sol-gel route where a natural copolymer; sodium alginate (Na-COOH) together with calcium oxide (CaO) powder were incorporated into silica sol precursor prior to gel formation. For this study, bulk xerogels samples were prepared with the amount of silica precursor and the natural copolymer was fixed meanwhile the loading of calcium oxide was varied at 10 and 20 wt%. The porous properties were studied and the comparison between the hybrid silica and monolith was made. The calcium oxide powder used in this study was prepared from calcium hydroxide, CaOH compound, which been calcined at 1000°C for 3 hours in normal air. Mesoporous structure with small particle size and glassy phase of matrixes are the main features of the prepared xerogels. The presence of sodium alginate and calcium oxide in silica matrixes produces a significant decrease especially in total surface area and porosity volume of the xerogel samples. Monolith silica xerogels exhibits a very large surface area approximately at 600 m2/g compared to the hybrid xerogels which showed 120m2/g and 25m2/g for the respective 10 and 20 wt.% of calcium oxide loading. Nevertheless, only a slight increased in pore size has been observed due to the increased amount of calcium oxide loading.

Sol-Gel Titania and Titania-Silica Mixed Oxides Photocatalysts

2010 ◽  
Vol 162 ◽  
pp. 221-238 ◽  
Author(s):  
Rafael van Grieken ◽  
José Aguado ◽  
María José López-Muñoz ◽  
Javier Marugán
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Surface Area ◽  
Photocatalytic Oxidation ◽  
Mixed Oxides ◽  
Sol Gel ◽  
Textural Properties ◽  
Total Surface Area ◽  
Band Gap Energy ◽  
Titania Incorporation

This paper presents a review of the work published by the authors on the synthesis, characterization and evaluation of the photocatalytic activity of TiO2/SiO2 materials. The use of titania-silica mixed oxides photocatalysts is proposed basically as a process improvement to overcome the difficulties of recovering titania from the slurries after the photocatalytic treatment of contaminated waters. To understand the mechanism governing the photocatalytic activity of these materials, several titania-silica photocatalysts have been prepared through a sol-gel method that allows controlling the main variables to obtain materials with different textural properties, degree of titania incorporation, dispersion of the photoactive phase and crystallinity of titanium dioxide. The samples have been characterized in depth, looking for correlations between the main physicochemical properties (TiO2 crystallite size, band gap energy and titania surface area) and the activity shown in the photocatalytic oxidation of cyanide, selected as model pollutant. The results suggest that the photocatalytic activity is strongly influenced by the quality of the titania crystal network, which in turn is improved by the use of a hydrothermal crystallization procedure. Additionally, the evaluation of the fraction of the total surface area corresponding to titania is mandatory for comparing the catalytic activity of different materials in processes in which titanium dioxide is the only phase catalytically active and silica behaves as an inert support.

scholarly journals Assessment of Ki-67 proliferation index with deep learning in DCIS (ductal carcinoma in situ)

2021 ◽  
Author(s):  
Lukasz Fulawka ◽  
Jakub Błaszczyk ◽  
Martin Tabakov ◽  
Agnieszka Halon
Keyword(s):  
Deep Learning ◽  
Surface Area ◽  
Ductal Carcinoma ◽  
Region Of Interest ◽  
Absolute Error ◽  
Visual Assessment ◽  
Total Surface Area ◽  
Proliferation Index ◽  
Ki 67 ◽  
The Impact

Abstract The proliferation index (PI) is crucial in histopathologic diagnostics, in particular tumors. It is calculated based on Ki-67 protein expression by immunohistochemistry. PI is routinely evaluated by a visual assessment of the sample by a pathologist. However, this approach is far from ideal due to its poor intra- and interobserver variability and time-consuming. These factors force the community to seek out more precise solutions. Virtual pathology as being increasingly popular in diagnostics, armed with artificial intelligence, may potentially address this issue. The proposed solution calculates the Ki-67 proliferation index by utilizing a deep learning model and fuzzy-set interpretations for hot-spots detection. The obtained region-of-interest is then used to segment relevant cells via classical methods of image processing. The index value is approximated by relating the total surface area occupied by immunopositive cells to the total surface area of relevant cells. The achieved results are compared to the manual calculation of the Ki-67 index made by a domain expert. To increase results reliability, we trained several models in a 3-fold manner and compared the impact of different hyper-parameters. Our best-proposed method estimates PI with 0,026 mean absolute error, which gives a significant advantage over the current state-of-the-art solution.

Evaluation of Nanotechniques and Conventional Techniques for the Removal of Dioxins

2018 ◽  
Vol 9 (1) ◽  
pp. 79-84
Author(s):  
Vaishali V. Shahare ◽  
Rajni Grover ◽  
Suman Meena
Keyword(s):  
Soil Sample ◽  
Human Health ◽  
Surface Area ◽  
Contaminated Soil ◽  
Conventional Treatment ◽  
Volume Ratio ◽  
Soil Samples ◽  
Dioxins And Furans ◽  
Palladized Iron ◽  
The Impact

Background: The persistent dioxins/furans has caused a worldwide concern as they influence the human health. Recent research indicates that nonmaterial may prove effective in the degradation of Dioxins/furans. The nanomaterials are very reactive owing to their large surface area to volume ratio and large number of reactive sites. However, nanotechnology applications face both the challenges and the opportunities to influence the area of environmental protection. Objective: i) To study the impact of oil mediated UV-irradiations on the removal of 2,3,7,8-TCDD, 2,3,7,8-TCDF, OCDD and OCDF in simulated soil samples. ii) To compare the conventional treatment methods with the modern available nanotechniques for the removal of selected Dioxins/furans from soil samples. Methods: The present work has investigated an opportunity of the degradation of tetra and octachlorinated dioxins and furans by using oil mediated UV radiations with subsequent extraction of respective dioxins/furans from soils. The results have been compared with the available nanotechniques. Results: The dioxin congeners in the simulated soil sample showed decrease in concentration with the increase in the exposure time and intensity of UV radiations. The dechlorination of PCDD/Fs using palladized iron has been found to be effective. Conclusion: Both the conventional methods and nanotechnology have a dramatic impact on the removal of Dioxins/furans in contaminated soil. However, the nanotechniques are comparatively costlier and despite the relatively high rates of PCDDs dechlorination by Pd/nFe, small fraction of the dioxins are recalcitrant to degradation over considerable exposure times.

Blue Emitting BaAl2O4:Ce3+ Nanophosphors with High Color Purity and Brightness for White LEDs

2019 ◽  
Vol 25 (6) ◽  
pp. 1466-1470 ◽  
Author(s):  
Rituparna Chatterjee ◽  
Subhajit Saha ◽  
Karamjyoti Panigrahi ◽  
Uttam Kumar Ghorai ◽  
Gopes Chandra Das ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Field Emission ◽  
Sol Gel ◽  
Blue Emission ◽  
Diffraction Field ◽  
White Leds ◽  
Display Devices ◽  
Transmission Electron ◽  
Structure Morphology ◽  
The Impact

AbstractIn this work, strongly blue emitting Ce3+-activated BaAl2O4 nanophosphors were successfully synthesized by a sol–gel technique. The crystal structure, morphology, and microstructure of the nanophosphors have been studied by X-ray powder diffraction, field emission scanning electron microscopy, and high-resolution transmission electron microscopy. The photoluminescence spectra show the impact of concentration variation of Ce3+ on the photoluminescence emission of the phosphor. These nanophosphors display intense blue emission peaking at 422 nm generated by the Ce3+ 5d → 4f transition under 350 nm excitation. Our results reveal that this nanophosphor has the capability to take part in the emergent domain of solid-state lighting and field-emission display devices.

scholarly journals Effect of Titanium Dioxide Nanoparticles on the Expression of Efflux Pump and Quorum-Sensing Genes in MDR Pseudomonas aeruginosa Isolates

Antibiotics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 625
Author(s):  
Fatma Y. Ahmed ◽  
Usama Farghaly Aly ◽  
Rehab Mahmoud Abd El-Baky ◽  
Nancy G. F. M. Waly
Keyword(s):  
Titanium Dioxide ◽  
Quorum Sensing ◽  
Biofilm Formation ◽  
Antimicrobial Agents ◽  
Efflux Pump ◽  
Titanium Dioxide Nanoparticles ◽  
Sol Gel ◽  
Efflux Pumps ◽  
Antibiofilm Activity ◽  
The Impact

Most of the infections caused by multi-drug resistant (MDR) P. aeruginosa strains are extremely difficult to be treated with conventional antibiotics. Biofilm formation and efflux pumps are recognized as the major antibiotic resistance mechanisms in MDR P. aeruginosa. Biofilm formation by P. aeruginosa depends mainly on the cell-to-cell communication quorum-sensing (QS) systems. Titanium dioxide nanoparticles (TDN) have been used as antimicrobial agents against several microorganisms but have not been reported as an anti-QS agent. This study aims to evaluate the impact of titanium dioxide nanoparticles (TDN) on QS and efflux pump genes expression in MDR P. aeruginosa isolates. The antimicrobial susceptibility of 25 P. aeruginosa isolates were performed by Kirby–Bauer disc diffusion. Titanium dioxide nanoparticles (TDN) were prepared by the sol gel method and characterized by different techniques (DLS, HR-TEM, XRD, and FTIR). The expression of efflux pumps in the MDR isolates was detected by the determination of MICs of different antibiotics in the presence and absence of carbonyl cyanide m-chlorophenylhydrazone (CCCP). Biofilm formation and the antibiofilm activity of TDN were determined using the tissue culture plate method. The effects of TDN on the expression of QS genes and efflux pump genes were tested using real-time polymerase chain reaction (RT-PCR). The average size of the TDNs was 64.77 nm. It was found that TDN showed a significant reduction in biofilm formation (96%) and represented superior antibacterial activity against P. aeruginosa strains in comparison to titanium dioxide powder. In addition, the use of TDN alone or in combination with antibiotics resulted in significant downregulation of the efflux pump genes (MexY, MexB, MexA) and QS-regulated genes (lasR, lasI, rhll, rhlR, pqsA, pqsR) in comparison to the untreated isolate. TDN can increase the therapeutic efficacy of traditional antibiotics by affecting efflux pump expression and quorum-sensing genes controlling biofilm production.

scholarly journals Suitability of Bronchoscopic Biopsy Tissue Samples for Next-Generation Sequencing

Diagnostics ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 391
Author(s):  
Shuji Murakami ◽  
Tomoyuki Yokose ◽  
Daiji Nemoto ◽  
Masaki Suzuki ◽  
Ryou Usui ◽  
...  
Keyword(s):  
Next Generation Sequencing ◽  
Success Rate ◽  
Rna Sequencing ◽  
Surface Area ◽  
Endobronchial Ultrasound ◽  
Next Generation ◽  
Endobronchial Ultrasonography ◽  
Tissue Surface ◽  
The Impact ◽  
Generation Sequencing

A sufficiently large tissue sample is required to perform next-generation sequencing (NGS) with a high success rate, but the majority of patients with advanced non-small-cell lung cancer (NSCLC) are diagnosed with small biopsy specimens. Biopsy samples were collected from 184 patients with bronchoscopically diagnosed NSCLC. The tissue surface area, tumor cell count, and tumor content rate of each biopsy sample were evaluated. The impact of the cut-off criteria for the tissue surface area (≥1 mm2) and tumor content rate (≥30%) on the success rate of the Oncomine Dx Target Test (ODxTT) was evaluated. The mean tissue surface area of the transbronchial biopsies was 1.23 ± 0.85 mm2 when small endobronchial ultrasonography with a guide sheath (EBUS-GS) was used, 2.16 ± 1.49 mm2 with large EBUS-GS, and 1.81 ± 0.75 mm2 with endobronchial biopsy (EBB). The proportion of samples with a tissue surface area of ≥1 mm2 was 48.8% for small EBUS-GS, 79.2% for large EBUS-GS, and 78.6% for EBB. Sixty-nine patients underwent ODxTT. The success rate of DNA sequencing was 84.1% and that of RNA sequencing was 92.7% over all patients. The success rate of DNA (RNA) sequencing was 57.1% (71.4%) for small EBUS-GS (n = 14), 93.4% (96.9%) for large EBUS-GS (n = 32), 62.5% (100%) for EBB (n = 8), and 100% (100%) for endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) (n = 15). Regardless of the device used, a tissue surface area of ≥ 1 mm2 is adequate for samples to be tested with NGS.

scholarly journals A Facile One-Pot Approach to the Synthesis of Gd-Eu Based Metal-Organic Frameworks and Applications to Sensing of Fe3+ and Cr2O72− Ions

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1679
Author(s):  
Roberta Puglisi ◽  
Anna L. Pellegrino ◽  
Roberto Fiorenza ◽  
Salvatore Scirè ◽  
Graziella Malandrino
Keyword(s):  
Surface Area ◽  
Metal Organic Frameworks ◽  
3D Structure ◽  
Inorganic Ions ◽  
Total Surface Area ◽  
One Pot ◽  
Green Approach ◽  
Metal Organic ◽  
Ft Ir ◽  
Xrd Patterns

Gadolinium metal-organic frameworks (Gd-MOFs) and Eu-doped Gd-MOFs have been synthesized through a one-pot green approach using commercially available reagents. The 1,4-benzenedicarboxylic acid (H2-BDC) and 2,6-naphthalenedicarboxylic acid (H2-NDC) were chosen as ditopic organic linkers to build the 3D structure of the network. The Gd-MOFs were characterized using powder X-ray diffraction (XRD), FT-IR spectroscopy, field emission scanning electron microscopy (FE-SEM) and N2 adsorption–desorption analysis. The Gd-MOF structures were attributed comparing the XRD patterns, supported by the FT-IR spectra, with data reported in the literature for Ln-MOFs of similar lanthanide ionic radius. FE-SEM characterization points to the effect of the duration of the synthesis to a more crystalline and organized structure, with grain dimensions increasing upon increasing reaction time. The total surface area of the MOFs has been determined from the application of the Brunauer–Emmett–Teller method. The study allowed us to correlate the processing conditions and ditopic linker dimension to the network surface area. Both Gd-MOF and Eu-doped Gd-MOF have been tested for sensing of the inorganic ions such as Fe3+ and Cr2O72−.

Sign in / Sign up

Export Citation Format

Share Document