A Study of Localized Corrosion in Al Resulting From The Controlled Introduction of Cl

2003 ◽  
Vol 781 ◽  
Author(s):  
C. M. Johnson ◽  
F. D. Wall ◽  
J. C. Barbour ◽  
M. A. Martinez
Keyword(s):  
Electron Microscopy ◽  
Corrosion Behavior ◽  
High Purity ◽  
Localized Corrosion ◽  
High Magnification ◽  
Sem Images ◽  
Optical And Electron Microscopy ◽  
Pit Nucleation ◽  
Microscopy Images

AbstractHigh purity Al samples were implanted with 35 keV Cl+ then polarized in Cl--free electrolyte in order to ascertain corrosion behavior as a function of Cl content. Electrochemical data indicated implant fluences between 5x1015 and 2x1016 Cl+cm-2 resulted in little or no localized attack. Implant fluences of 3x1016 and 5x1016 Cl+cm-2 resulted in significant attack with the severity scaling as a function of implant fluence. The low variability in the behavior of localized corrosion for the 5x1016 Cl+cm-2 sample suggests that this implant dosage may result in a critical Cl- in the sample for pit nucleation. Optical and Electron microscopy images indicated some reactivity associated with lower fluences (1x1016Cl+cm-2), possibly indicating enhanced general dissolution. At high magnification the corrosion was observed to occur outside the implanted boundary through mechanisms of tunneling or altered local chemistry at those sites. The SEM images reveal a form of localized corrosion with a crystalline character.

Electrochemical Corrosion Behavior of Cu-15Ni-8Sn Alloy in Marine Microbial Medium

2009 ◽  
Vol 79-82 ◽  
pp. 1099-1102
Author(s):  
Yan Hua Lei ◽  
Yan Sheng Yin ◽  
Chao Hong Liu ◽  
Xue Ting Chang ◽  
Yan Chen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Corrosion Behavior ◽  
Electrochemical Corrosion ◽  
Rich Medium ◽  
Sem Images ◽  
Electrochemical Corrosion Behavior ◽  
Nutrient Rich Medium ◽  
Simulated Seawater ◽  
Control Samples ◽  
Scanning Electron

A comparative study of the corrosion behavior of the copper-nickel-tin alloy in a nutrient–rich simulated seawater-based nutrient-rich medium in the presence and the absence of the marine bacteria was carried out by electrochemical experiments, microscopic methods. Comparing to the corresponding control samples, the electrochemical data demonstrated that the presence of the bacteria accelerated the corrosion of the alloy. Scanning electron microscopy (SEM) images revealed the occurrence of micro-pitting and intergranular corrosion underneath the biofilm on the alloy surface.

scholarly journals TEM of Bacteriophages Found in Marine Sources

2007 ◽  
Vol 15 (6) ◽  
pp. 28-31 ◽  
Author(s):  
Adella Fejeran ◽  
Jesus Polanco ◽  
Gabriel Lander ◽  
Teddy Ajero ◽  
Bridget Carragher ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High School ◽  
High School Students ◽  
High Magnification ◽  
Sample Collection ◽  
School Students ◽  
Microscopy Imaging ◽  
Research Education ◽  
Transmission Electron ◽  
Microscopy Images

AbstractWe describe here a project to illustrate the diversity and abundance of marine bacteriophages undertaken by two high school students participating in The Scripps Research Institute's High School Student Research Education Program. The students were interns in the Automated Molecular Imaging group over the summer of 2007, during which time they acquired high magnification transmission electron microscopy images of bacteriophage filtered from samples collected from nearby marine waters. The basic protocols for sample collection, grid preparation, and electron microscopy imaging are described in this manuscript along with some of the images of the bacteriophages.

scholarly journals The accumulation of colibactin intermediates does not affect the growth and morphology of pks+Escherichia coli

2020 ◽  
Author(s):  
Yermary Morales-Lozada ◽  
Ramón Gómez-Moreno ◽  
Gabriela Báez-Bravo ◽  
Iraida E. Robledo ◽  
Dámaris Suazo-Dávila ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Deletion Mutant ◽  
Genomic Island ◽  
Spherical Shape ◽  
High Resolution Electron Microscopy ◽  
Wild Type ◽  
Sem Images ◽  
E Coli ◽  
Resolution Electron ◽  
Microscopy Images

AbstractColibactin is a natural product made by numerous strains of E. coli that harbor the pks genomic island. The deletion of one of the genes within the pks island, the peptidase clbP, has been found to disrupt the maturation of colibactin, thus promoting the accumulation in the periplasmic space of numerous biosynthesis intermediates, some of which have been characterized chemically. To date, no one has reported the effect of such an accumulation of intermediates on the cellular morphology of the producing E. coli bacterium. In this report, we describe the scanning electron microscopy (SEM) images of numerous clinical isolates of E. coli harboring the pks island, collected from Puerto Rico hospitals. We have observed that the wild type isolates that harbor the pks island display lesions on the bacterial envelope surface. These lesions are absent in isolates lacking the pks island. To determine whether this phenotype is associated with colibactin production, we deleted the clbP gene from the extraintestinal pathogenic E. coli strain IHE3034, thus disrupting its ability to make colibactin. The wild-type IHE3034 displayed a spherical shape with no envelope lesions, and was practically indistinguishable from the ΔclbP deletion mutant. To our knowledge, this work provides the first SEM images of a pks deletion mutant.ImportanceThe pks genomic island has been linked to the promotion of DNA damage and colorectal cancer, through the production of genotoxic compound colibactin in some strains of E. coli. While much is known about the mechanism of colibactin toxicity once it enters the mammalian cell, the prior steps leading to colibactin secretion or translocation from the bacterial cell, remain unclear. Here, we report high-resolution electron microscopy images of E. coli IHE3034 strain, a known colibactin producer, and a deletion mutant that is known to accumulate colibactin intermediates. The images reveal a predominantly spherical morphology that is unaffected by the accumulation of colibactin precursors and intermediates.

Sem Studies of Co-Cr-Mo Surgical Implant Alloy Corrosion Behavior

1982 ◽  
Vol 40 ◽  
pp. 520-521
Author(s):  
Ann Chidester Van Orden ◽  
John L. Chidester ◽  
Anna C. Fraker ◽  
Pei Sung
Keyword(s):  
Electron Microscopy ◽  
Corrosion Behavior ◽  
Anodic Polarization ◽  
Saline Solution ◽  
Saturated Calomel Electrode ◽  
Physiological Saline ◽  
X Ray ◽  
Physiological Saline Solution ◽  
Scanning Electron

The influence of small variations in the composition on the corrosion behavior of Co-Cr-Mo alloys has been studied using scanning electron microscopy (SEM), energy dispersive x-ray analysis (EDX), and electrochemical measurements. SEM and EDX data were correlated with data from in vitro corrosion measurements involving repassivation and also potentiostatic anodic polarization measurements. Specimens studied included the four alloys shown in Table 1. Corrosion tests were conducted in Hanks' physiological saline solution which has a pH of 7.4 and was held at a temperature of 37°C. Specimens were mechanically polished to a surface finish with 0.05 µm A1203, then exposed to the solution and anodically polarized at a rate of 0.006 v/min. All voltages were measured vs. the saturated calomel electrode (s.c.e.).. Specimens had breakdown potentials near 0.47V vs. s.c.e.

A Transmission Electron Microscopical Investigation of Phase Transformations in TiNi

1980 ◽  
Vol 38 ◽  
pp. 340-341
Author(s):  
P. Moine ◽  
G. M. Michal ◽  
R. Sinclair
Keyword(s):  
Electron Microscopy ◽  
Phase Transformations ◽  
Applied Stress ◽  
Structural Changes ◽  
Microscopical Investigation ◽  
Temperature Range ◽  
Transmission Electron ◽  
Electron Microscopical ◽  
Diffraction Effects ◽  
Microscopy Images

Premartensitic effects in near equiatomic TiNi have been pointed out by several authors(1-5). These include anomalous contrast in electron microscopy images (mottling, striations, etc. ),diffraction effects(diffuse streaks, extra reflections, etc.), a resistivity peak above Ms (temperature at which a perceptible amount of martensite is formed without applied stress). However the structural changes occuring in this temperature range are not well understood. The purpose of this study is to clarify these phenomena.

scholarly journals Clay-Based Brick Porosity Estimation Using Image Processing Techniques

2019 ◽  
Vol 29 (1) ◽  
pp. 1226-1234
Author(s):  
Safa Jida ◽  
Hassan Ouallal ◽  
Brahim Aksasse ◽  
Mohammed Ouanan ◽  
Mohamed El Amraoui ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Image Processing ◽  
Scanning Electron Microscopy ◽  
Computer Vision ◽  
Image Processing Techniques ◽  
Processing Techniques ◽  
Porosity Estimation ◽  
Microscopy Images ◽  
Scanning Electron

Abstract This work intends to apprehend and emphasize the contribution of image-processing techniques and computer vision in the treatment of clay-based material known in Meknes region. One of the various characteristics used to describe clay in a qualitative manner is porosity, as it is considered one of the properties that with “kill or cure” effectiveness. For this purpose, we use scanning electron microscopy images, as they are considered the most powerful tool for characterising the quality of the microscopic pore structure of porous materials. We present various existing methods of segmentation, as we are interested only in pore regions. The results show good matching between physical estimation and Voronoi diagram-based porosity estimation.

scholarly journals Antitumor Potential of Green Synthesized ZnONPs Using Root Extract of Withania somnifera against Human Breast Cancer Cell Line

Separations ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 8
Author(s):  
Kollur Shiva Prasad ◽  
Shashanka K Prasad ◽  
Ravindra Veerapur ◽  
Ghada Lamraoui ◽  
Ashwini Prasad ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cell Line ◽  
Withania Somnifera ◽  
Root Extract ◽  
Dependent Manner ◽  
Sem Images ◽  
Xrd Pattern ◽  
Transmission Electron

Herein we report the synthesis of zinc oxide nanoparticles (ZnONPs) using Withania somnifera root extract (WSE) as an effective chelating agent. The microscopic techniques viz., X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and selected area electron diffraction (SAED) were employed to analyze the as-obtained ZnONPs. The crystalline planes observed from the XRD pattern agrees with the hexagonal wurtzite structure of the as-prepared ZnONPs. The aggregations and agglomerations observed in the SEM images indicated that the size of the as-prepared ZnONPs was between 30 and 43 nm. The interplanar distance between the lattice fringes observed in the HRTEM image was found to be 0.253 nm, which is in good agreement with the (100) plane obtained in the XRD pattern. Furthermore, the anti-breast cancer cytotoxic evaluation was carried out using the MCF-7 cell line, and the results showed significant cytotoxic effects in a dose-dependent manner.

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