Effects of Aluminum Implantation on the Oxidation Behavior of Silicon Nitride in a Sodium Nitrate-Oxygen Gas Mixture

1996 ◽  
Vol 438 ◽  
Author(s):  
Y. Cheong ◽  
H. Du ◽  
S. P. Withrow
Keyword(s):  
Sodium Nitrate ◽  
Marked Improvement ◽  
Oxidation Behavior ◽  
Morphological Characteristics ◽  
Aluminum Concentration ◽  
Gas Mixture ◽  
Aluminum Implantation ◽  
Oxygen Gas ◽  
Si3n4 Ceramics

AbstractThe role of aluminum in negating the adverse effect of alkali species on the oxidation resistance of Si3N4 ceramics was investigated by exposing unimplanted and aluminum-implanted (1 and 5 at.%) Si3N4 samples to a sodium nitrate (95 ppm)-dry oxygen gas mixture at 1. atm and at 900°1100°C. Oxidation of unimplanted Si3N4 was rapid and linear with an activation energy of 57 kJ/mol. In contrast, samples implanted with aluminum exhibited a considerably reduced oxide growth which was parabolic in nature with activation energies of 103–112 kJ/mol. The morphological characteristics of the oxide layer also showed marked improvement as the aluminum concentration increased.

Therapeutic efficacy of Kantakari Ghrita in Tamaka Shwasa

2018 ◽  
Vol 3 (01) ◽  
Author(s):  
Dhanesh Kannan ◽  
Ravindra Angadi ◽  
Krishnendu O. Nambiar
Keyword(s):  
Marked Improvement ◽  
Signs And Symptoms ◽  
Unique Property ◽  
Test Design ◽  
Once Daily ◽  
Respiratory Condition ◽  
Post Test ◽  
Clinical Practise ◽  
Single Blind

Background: Ghrta Kalpana has a major role in clinical practise, because of its unique property of Samskarasya Anuvartanam. Tamaka Shwasa a Pranavaha Srothovikara, may be correlated to Bronchial Asthma, where in remissions and exacerbations are the typical features. The management of this acute respiratory condition is the long quest in the medical fraternity of all types. Hence, the present study was aimed to evaluate the role of Shamana therapy in the form of Kantakari Ghrta3 in Tamaka Shwasa patients. Objectives: To evaluate the effect of Kantakari Ghrta in Tamaka Shwasa. Methods: A total number of 30 patients were administered with 24 mgs of ‘Kantakari Ghrta’ once daily in the morning on empty stomach with Ushna Jala as Anupana. It was a single blind study with pre and post-test design. The effect was assessed by standard scoring assessment criteria followed by statistical analyses. Results: There was marked improvement in signs and symptoms and all were statistically significant. .

Preparation of hydrophobic flat sheet membranes from PVDF-HFP copolymer for enhancing the oxygen permeance in nitrogen/oxygen gas mixture

2020 ◽  
Vol 28 (6) ◽  
pp. 1566-1581
Author(s):  
Bahador Akbari ◽  
Asghar Lashanizadegan ◽  
Parviz Darvishi ◽  
Abdolrasoul Pouranfard
Keyword(s):  
Gas Mixture ◽  
Flat Sheet ◽  
Oxygen Gas

The cell biology and pathogenic role of pulmonary intravascular macrophages

1990 ◽  
Vol 258 (2) ◽  
pp. L1-L12 ◽  
Author(s):  
A. E. Warner ◽  
J. D. Brain
Keyword(s):  
Acute Lung Injury ◽  
Lung Injury ◽  
Cell Biology ◽  
Morphological Characteristics ◽  
Laboratory Animals ◽  
Capillary Endothelium ◽  
Phagocytic Cells ◽  
Pulmonary Uptake ◽  
Pulmonary Intravascular Macrophages

Pulmonary intravascular macrophages (PIMs) are an extensive population of mature phagocytic cells adherent to the pulmonary capillary endothelium in selected species. They are not prevalent in lungs of commonly studied laboratory animals, such as rodents, and thus have only been recently appreciated. However, their potential role in host defense and acute lung injury has attracted interest, since a number of studies have demonstrated pulmonary localization of circulating particles, microbes, and endotoxin by PIMs. Those animal species, such as ruminants, that provide useful models of pathogen (or endotoxin)-induced acute lung injury demonstrate rapid pulmonary uptake of bacteria by PIMs. Inflammatory mediators released by activated PIMs may initiate the process and provoke accumulation of neutrophils and platelets. This review summarizes the morphological characteristics of PIMs and their species distribution. The role of these members of the mononuclear phagocyte system, both beneficial and potentially pathogenic, is reviewed. The question of whether PIMs have a role in acute lung injury in humans is also discussed.

Biogeochemistry and microbiology of microaerobic Fe(II) oxidation

2012 ◽  
Vol 40 (6) ◽  
pp. 1211-1216 ◽  
Author(s):  
David Emerson
Keyword(s):  
Hydrothermal Vents ◽  
Cytoplasmic Membrane ◽  
Iron Oxidation ◽  
Morphological Characteristics ◽  
Genomic Analysis ◽  
Freshwater Wetlands ◽  
Iron Oxidizing Bacteria ◽  
Resident Populations ◽  
Extracellular Electron Transport

Today high Fe(II) environments are relegated to oxic–anoxic habitats with opposing gradients of O2 and Fe(II); however, during the late Archaean and early Proterozoic eons, atmospheric O2 concentrations were much lower and aqueous Fe(II) concentrations were significantly higher. In current Fe(II)-rich environments, such as hydrothermal vents, mudflats, freshwater wetlands or the rhizosphere, rusty mat-like deposits are common. The presence of abundant biogenic microtubular or filamentous iron oxyhydroxides readily reveals the role of FeOB (iron-oxidizing bacteria) in iron mat formation. Cultivation and cultivation-independent techniques, confirm that FeOB are abundant in these mats. Despite remarkable similarities in morphological characteristics between marine and freshwater FeOB communities, the resident populations of FeOB are phylogenetically distinct, with marine populations related to the class Zetaproteobacteria, whereas freshwater populations are dominated by members of the Gallionallaceae, a family within the Betaproteobacteria. Little is known about the mechanism of how FeOB acquire electrons from Fe(II), although it is assumed that it involves electron transfer from the site of iron oxidation at the cell surface to the cytoplasmic membrane. Comparative genomics between freshwater and marine strains reveals few shared genes, except for a suite of genes that include a class of molybdopterin oxidoreductase that could be involved in iron oxidation via extracellular electron transport. Other genes are implicated as well, and the overall genomic analysis reveals a group of organisms exquisitely adapted for growth on iron.

scholarly journals MORPHOLOGICAL CHARACTERISTICS OF THE GIANH RIVER (FROM CO CANG TO CUA GIANH) IN RELATION TO THE EROSION AND ACCUMULATION

2019 ◽  
Vol 18 (4) ◽  
pp. 384-392
Author(s):  
Hai Nguyen Tien ◽  
Dang Vu Hai ◽  
Phuc La The ◽  
Ha Nguyen Thai
Keyword(s):  
River Flow ◽  
Dominant Role ◽  
Morphological Characteristics ◽  
Straight Channel ◽  
Meandering Channel ◽  
Braided Channel ◽  
River Bed ◽  
Erosion And Accretion ◽  
Channel Bar

On the basis of morphological characteristics and erosion - accumulation of sediment, it is possible to divide the stretch of the Gianh River from Co Cang to Cua Gianh (about 54km in length) into 3 sections as follows: Meandering channel (from Co Cang to Tien Xuan Isles): the length of the channel is 27.69km and the width of the channel is 80-250m. The channel is in the form of a meandering, narrow riverbed, flow plays a dominant role, deposition activities develop strongly at the convex side, while erosion occurs strongly in the concave side (cut side); Braided channel (from Tien Xuan Isles to Quang Phu): the length of the channel is 17.06km and the width of the channel is 800-2,200m. The channel is straight, the river bed is large and the depth of the river bed is 2-11m. Sedimentation occurs mainly at the bottom of the channel and creates bar in the middle of the channel; Straight channel (from Quang Phu to Cua Gianh): the length of the channel is 9.23km and the width of the channel is 800-1,000m. The channel is straight and the depth of the river bed is 8-12.5m. In addition to the role of river flow, it is strongly influenced by marine dynamics. The erosion and accretion activities occur mainly in estuaries. The results above show trend of river development: i) Meandering channel is the most vulnerable to changes for morphology of channel by erosion and accretion of sediment and can create 1-2 horseshoe pools by the river change line; ii) Braided channel mainly changes in the bottom of channel by the formation of channel bar; iii) Straight channel mainly changes in the estuary (the mouth of the river can be moved, enlarged or narrowed).

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