A Role of NO2 on Soot Oxidation in DPFs and Effect of Soot Cake Thickness in Catalyzed DPFs Using Temperature-Programmed Oxidation and Electron Microscopic Visualization

2020 ◽  
Author(s):  
Mek Srilomsak ◽  
Katsunori Hanamura
Keyword(s):  
Soot Oxidation ◽  
Electron Microscopic ◽  
Temperature Programmed Oxidation ◽  
Cake Thickness ◽  
Temperature Programmed

scholarly journals Simultaneous Elimination of Soot and NOX through Silver-Barium Based Catalytic Materials

2017 ◽  
Vol 12 (1) ◽  
pp. 71 ◽  
Author(s):  
Ganesh Chandra Dhal ◽  
Subhashish Dey ◽  
Ram Prasad ◽  
Devendra Mohan
Keyword(s):  
Soot Oxidation ◽  
Impregnation Method ◽  
Soot Combustion ◽  
Temperature Programmed Oxidation ◽  
Intrinsic Factors ◽  
Catalytic Materials ◽  
Concentration Step ◽  
Temperature Programmed ◽  
Nanometric Size ◽  
Simultaneous Elimination

<p>In this research paper, the nanometric size effect, the effects of the intrinsic factors including structure, and the redox properties of three systems of nanometric of silver-based catalysts were summarized. In this work, these catalysts were investigated for the simultaneous removal of particulate matter (diesel soot), and NO<sub>X</sub> was compared with that of a model of Pt-Ba/Al<sub>2</sub>O<sub>3 </sub>catalyst. The Silver-Barium based catalytic materials of Ag (5 wt%)-Ba(10 wt%)/MO (MO=Al<sub>2</sub>O<sub>3</sub>, CeO<sub>2</sub>, ZrO<sub>2</sub>,) and Ag (5 wt%)-Sr (10 wt%)/CeO<sub>2</sub> catalysts have been prepared by wetness impregnation method and characterized by BET, XRD, HRTEM, XPS and TPR (temperature-programmed reduction) experiments. The behavior of the catalyst in the soot combustion (under tight conditions) and NO<sub>X</sub> elimination has been separately analyzed by means of temperature programmed oxidation and isothermal concentration step change experiments, respectively. The results showed that all the catalysts were active in soot combustion with an indicative decrease of oxidation onset temperature compared to uncatalyzed soot oxidation. The removal of NO<sub>X</sub> in the presence and in the absence of soot was investigated under cycling conditions, i.e. alternating lean-rich phases according to the LNT approach. It has been found that the Ag-based samples were able to simultaneously remove soot and NO<sub>X</sub>. In particular, studying the behavior of the prepared catalysts, the Ba-containing systems exhibited higher NO<sub>X</sub> storage capacity than Sr-catalyst; also, the nitrogen selectivity increased even if resulted lower than the traditional LNT Pt-based catalyst. An adverse effect of soot on the NO<sub>X </sub>storage activity has been also observed. Copyright © 2017 BCREC GROUP. All rights reserved</p><p><em>Received: 18<sup>th</sup> August 2016; Revised: 19<sup>th</sup> October 2016; Accepted: 19<sup>th</sup> October 2016</em></p><p><strong>How to Cite:</strong> Dhal, G.C., Dey, S., Prasad, R., Mohan, D. (2017). Simultaneous Elimination of Soot and NO<sub>X </sub>through Silver-Barium Based Catalytic Materials. <em>Bulletin of Chemical Reaction Engineering &amp; Catalysis</em>, 12 (1): 71-80 (doi:10.9767/bcrec.12.1.647.71-80)</p><p><strong>Permalink/DOI:</strong> http://dx.doi.org/10.9767/bcrec.12.1.647.71-80</p><p> </p>

Stannous fluoride treatment of acid-etched caries-like lesions of enamel: A scanning electron microscopic study

1984 ◽  
Vol 42 ◽  
pp. 720-721
Author(s):  
M. John Hicks ◽  
Leon M. Silverstone ◽  
David G. Gantt ◽  
Catherine M. Flaitz
Keyword(s):  
Acid Etching ◽  
Surface Zone ◽  
Electron Microscopic ◽  
Fluoride Treatment ◽  
Stannous Fluoride ◽  
Scanning Electron Microscopic Study ◽  
Demineralized Enamel ◽  
Intact Surface ◽  
Topical Fluoride

Although fluoride levels become elevated in sound enamel following a topical fluoride treatment, the caries-preventive effect of fluoride is thought to be due primarily to the role of fluoride in remineralization of clinically undetectable enamel lesions and hypomineralized enamel. During lesion formation, redistribution of fluoride from the enamel surface to the subsurface demineralized enamel occurs. This results in a surface zone with a relatively low fluoride content. In order to maintain an intact surface zone over a carious lesion, it may be necessary to replenish the fluoride levels with an exogenous fluoride source. By acid-etching the lesion surface, a more reactive surface is made available for fluoride interaction. In addition, porosities and etching patterns may be created, allowing for bonding of a caries-resistant resin material to the lesion surface. The purpose of this study was to determine the integrity of the caries-like lesion surface following acid-etching and subsequent stannous fluoride treatment (SnF2).

Scanning electron microscopic study of collagen fibrillogenesis and extracellular compartmentalization in the chick embryo tendon

1986 ◽  
Vol 44 ◽  
pp. 208-209
Author(s):  
Grace C.H. Yang
Keyword(s):  
Chick Embryo ◽  
Extracellular Space ◽  
Fibroblast Cell ◽  
Collagen Fibrils ◽  
Electron Microscopic ◽  
Voltage Electron ◽  
Scanning Electron Microscopic Study ◽  
Microscopic Studies ◽  
And Function

The size and organization of collagen fibrils in the extracellular matrix is an important determinant of tissue structure and function. The synthesis and deposition of collagen involves multiple steps which begin within the cell and continue in the extracellular space. High-voltage electron microscopic studies of the chick embryo cornea and tendon suggested that the extracellular space is compartmentalized by the fibroblasts for the regulation of collagen fibril, bundle, and tissue specific macroaggregate formation. The purpose of this study is to gather direct evidence regarding the association of the fibroblast cell surface with newly formed collagen fibrils, and to define the role of the fibroblast in the control and the precise positioning of collagen fibrils, bundles, and macroaggregates during chick tendon development.

scholarly journals Role of CO2 During Oxidative Dehydrogenation of Propane Over Bulk and Activated-Carbon Supported Cerium and Vanadium Based Catalysts

2021 ◽  
Author(s):  
Petar Djinović ◽  
Janez Zavašnik ◽  
Janvit Teržan ◽  
Ivan Jerman
Keyword(s):  
Catalytic Activity ◽  
Activated Carbon ◽  
Oxidative Dehydrogenation ◽  
Active Phase ◽  
Lattice Oxygen ◽  
Chemisorbed Oxygen ◽  
Catalytically Active ◽  
Temperature Programmed ◽  
Propane Cracking

AbstractCeO2, V2O5 and CeVO4 were synthesised as bulk oxides, or deposited over activated carbon, characterized by XRD, HRTEM, CO2-TPO, C3H8-TPR, DRIFTS and Raman techniques and tested in propane oxidative dehydrogenation using CO2. Complete oxidation of propane to CO and CO2 is favoured by lattice oxygen of CeO2. The temperature programmed experiments show the ~ 4 nm AC supported CeO2 crystallites become more susceptible to reduction by propane, but less prone to re-oxidation with CO2 compared to bulk CeO2. Catalytic activity of CeVO4/AC catalysts requires a 1–2 nm amorphous CeVO4 layer. During reaction, the amorphous CeVO4 layer crystallises and several atomic layers of carbon cover the CeVO4 surface, resulting in deactivation. During reaction, V2O5 is irreversibly reduced to V2O3. The lattice oxygen in bulk V2O5 favours catalytic activity and propene selectivity. Bulk V2O3 promotes only propane cracking with no propene selectivity. In VOx/AC materials, vanadium carbide is the catalytically active phase. Propane dehydrogenation over VC proceeds via chemisorbed oxygen species originating from the dissociated CO2. Graphic Abstract

Etude ultrastructurale des relations hôte–parasite au cours de l'infection des pommes par le Phytophthora cactorum

1981 ◽  
Vol 59 (2) ◽  
pp. 251-263 ◽  
Author(s):  
X. Mourichon ◽  
G. Sallé
Keyword(s):  
Cell Walls ◽  
Susceptible Variety ◽  
Host Cells ◽  
Phytophthora Cactorum ◽  
Electron Microscopic ◽  
Susceptible Host ◽  
Golden Delicious ◽  
Extrahaustorial Matrix ◽  
Apple Fruits

An electron microscopic study was performed on haustoria of Phytophthora cactorum (L. et C.) Schroeter developed in tissues of two cultivars of apple fruits: a susceptible variety ('Golden delicious') and a resistant one ('Belle de Boskoop'). Ultrastructure of intercellular hyphae and some aspects of their penetration between contiguous host cells were described. A light dissolution of the host cell walls was observed. Ontogenic investigations indicated that in the susceptible host, the wall of the fungal haustoria was covered with a dense-stained extrahaustorial matrix. Its origin and its polysaccharide nature were demonstrated. On the other hand, the resistant host developed, immediately after the inoculation, a papilla which gave rise, later on, to a sheath enclosing adult haustoria. The role of these callosic structures in the phenomenon of resistance was discussed.

N2O Temperature-Programmed Oxidation and EXAFS Studies on the Dispersion of Copper in Ceria-Supported Nanocatalysts

2005 ◽  
Vol 17 (15) ◽  
pp. 3935-3943 ◽  
Author(s):  
A. Tschöpe ◽  
J. Markmann ◽  
P. Zimmer ◽  
R. Birringer ◽  
Chadwick
Keyword(s):  
Temperature Programmed Oxidation ◽  
Temperature Programmed

Role of interfacial interactions to control the extent of wrapping of polymer chains on multi-walled carbon nanotubes

RSC Advances ◽  
2016 ◽  
Vol 6 (48) ◽  
pp. 42334-42346 ◽  
Author(s):  
Suchitra Parija ◽  
Arup R. Bhattacharyya
Keyword(s):  
Polymer Chains ◽  
Electron Microscopic ◽  
Α Phase ◽  
Transmission Electron ◽  
Transmission Electron Microscopic ◽  
Electron Microscopic Image ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Transmission Electron Microscopic Image

Transmission electron microscopic image of separated MWCNTs (N51L15G5) showing the wrapped polymer chains on the MWCNTs surface, which corresponds to the α-phase of the PP.

Abstract WMP31: Dedifferentiation of Smooth Muscle Cells and its Potential Contribution to Pathogenesis of Intracranial Aneurysms

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Mieko Oka ◽  
Nobuhiko Ohno ◽  
Takakazu Kawamata ◽  
Tomohiro Aoki
Keyword(s):  
Endothelial Cells ◽  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Inflammatory Responses ◽  
Muscle Cells ◽  
Inflammatory Factors ◽  
Potential Contribution ◽  
Electron Microscopic

Introduction: Intracranial aneurysm (IA) affects 1 to 5 % in general public and becomes the primary cause of subarachnoid hemorrhage, the most severe form of stroke. However, currently, no drug therapy is available for IAs to prevent progression and rupture of lesions. Elucidation of mechanisms underlying the disease is thus mandatory. Considering the important role of vascular smooth muscle cells (SMCs) in the maintenance of stiffness of arterial walls and also in the pathogenesis of atherosclerosis via mediating inflammatory responses, we in the present study analyzed morphological or phenotypical changes of SMCs during the disease development in the lesions. Methods: We subjected rats to an IA model in which lesions are induced by increase of hemodynamic force loading on intracranial arterial bifurcations and performed histopathological analyses of induced lesions including the electron microscopic examination. We then immunostained specimens from induced lesions to explore factors responsible for dedifferentiation or migration of SMCs. In vitro study was also done to examine effect of some candidate factors on dedifferentiation or migration of cultured SMCs. Results: We first found the accumulation of SMCs underneath the endothelial cell layer mainly at the neck portion of the lesion. These cells was positive for the embryonic form of myosin heavy chain, a marker for the dedifferentiated SMCs, and the expression of pro-inflammatory factors like TNF-α. In immunostaining to explore the potential factor regulating the dedifferentiation of SMCs, we found that Platelet-derived growth factor-BB (PDGF-BB) was expressed in endothelial cells at the neck portion of IA walls. Consistently, recombinant PDGF-BB could promote the dedifferentiate of SMCs and chemo-attracted them in in vitro. Finally, in the stenosis model of the carotid artery, PDGF-BB expression was induced in endothelial cells in which high wall shear stress was loaded and the dedifferentiation of SMCs occurred there. Conclusions: The findings from the present study imply the role of dedifferentiated SMCs partially recruited by PDGF-BB from endothelial cells in the formation of inflammatory microenvironment at the neck portion of IA walls, leading to the progression of the disease.

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