Determination of the instantaneous rate of atmospheric corrosion

1978 ◽  
Vol 29 (7) ◽  
pp. 456-460 ◽  
Author(s):  
J. A. González
Keyword(s):  
Atmospheric Corrosion ◽  
Instantaneous Rate

scholarly journals DETERMINATION OF ATMOSPHERIC CORROSION RATE OF METALS IN 12 VIETNAMESE AREAS

2018 ◽  
Vol 55 (5B) ◽  
pp. 272
Author(s):  
Pham Duy Nam
Keyword(s):  
Carbon Steel ◽  
Corrosion Rate ◽  
Rural Areas ◽  
Atmospheric Corrosion ◽  
Climatic Factors ◽  
Air Pollutant ◽  
Climatic Data ◽  
Corrosion Rates ◽  
Copper Aluminum

The corrosion of materials is a result of complex impact from many climatic factors such as temperature, humidity, air pollutant content in the air, rainfall etc. In addition, the corrosion rate of metals can be measured. Each climatic zone is characterized by its corrosion rate. This article presents the testing results to determine the corrosion rate of carbon steel, copper, aluminum and zinc in 12 districts characterizing different climate zones of Vietnam. Testing, evaluation, and classification of atmospheric corrosion were conducted in accordance with the standard ISO 9223. The results show that for all types of studied metals, their corrosion rates which are determined from climatic data are higher than the corrosion rates in reality, especially for carbon steel and aluminum. This difference is more visible in the rural areas.

Determination of the rate of atmospheric corrosion of metal structures by the method of polarization resistance

2012 ◽  
Vol 47 (5) ◽  
pp. 683-688 ◽  
Author(s):  
L. I. Nyrkova ◽  
S. H. Polyakov ◽  
S. O. Osadchuk ◽  
S. L. Mel’nychuk ◽  
N. O. Hapula
Keyword(s):  
Polarization Resistance ◽  
Atmospheric Corrosion ◽  
Metal Structures

Measurements of blood flow to individual glomeruli in the ophidian kidney

1990 ◽  
Vol 258 (6) ◽  
pp. R1313-R1319 ◽  
Author(s):  
S. D. Yokota ◽  
W. H. Dantzler
Keyword(s):  
Blood Flow ◽  
Plasma Osmolality ◽  
Blood Flow Rate ◽  
Vessel Diameter ◽  
Intermittent Flow ◽  
Thamnophis Sirtalis ◽  
Instantaneous Rate ◽  
Single Nephron ◽  
The Difference

Continuous measurements of the instantaneous rate of blood flow to individual glomeruli in a normal vertebrate kidney were made in the garter snake Thamnophis sirtalis. Epifluorescence video microscopy was used to visualize and record blood flow in the afferent arterioles of superficial nephrons. The dual-slit method was used for the determination of red blood cell (RBC) velocity from the video replay. Simultaneous measurements of the vessel diameter allowed the continuous determination of the instantaneous rate of blood flow. A total of 100 glomeruli was surveyed in 12 animals. These glomeruli displayed both constant and highly variable rates of blood flow, with 21% of all nephrons displaying intermittent glomerular perfusion. The mean single-nephron blood flow rate (SNBFR) for all individuals was 23.9 +/- 10.3 (SD) nl/min (n = 12). The percentage of nephrons with intermittent flow for an individual animal increased significantly with increasing plasma osmolality. Intermittency was associated with low SNBFR values; SNBFR averaged 13.5 +/- 10.2 (SD) nl/min (n = 21) in intermittent nephrons and 29.2 +/- 19.0 (SD) nl/min (n = 79) in continuous flow nephrons, the difference being significant (P less than 0.001). Nephrons with continuous perfusion displayed a much greater range of SNBFR values than intermittent nephrons. This suggests that, although changes in whole kidney glomerular filtration rate (GFR) in reptiles need not involve glomerular intermittency, intermittency may lower GFR.

Influence of Lead on Zinc Roofing Resistance to Atmospheric Corrosion

2008 ◽  
Vol 59 (5) ◽  
Author(s):  
Maria Faur
Keyword(s):  
Atmospheric Corrosion ◽  
Active Role ◽  
Corrosion Process ◽  
Metallic Surface ◽  
Chemical Heterogeneity ◽  
Material Distribution ◽  
Metallic Material ◽  
Micro Analysis

The paper presents the researches carried out for the determination of the chemical heterogeneity influence of zinc roofing metallic surface on the resistance to atmospheric corrosion. Emphasizing of transformations taking place on the surface and inside the structure of metallic material, distribution, depth and form of corrosive attack, as well as micro-analysis of grain boundary and of adjacent corroded surfaces led to determine the lead influence. It was demonstrated the active role of lead, although it was considered harmless concerning the zinc roofing resistance to atmosphere corrosion, for the initiation and evolution of �pitting� corrosion process.

Investigation of atmospheric corrosion with use of permanent corrosion stations

2012 ◽  
Vol 30 (1) ◽  
pp. 25-44 ◽  
Author(s):  
Piotr Barszcz
Keyword(s):  
Atmospheric Corrosion ◽  
Field Tests ◽  
Research Process ◽  
Technical Condition ◽  
Corrosion Process ◽  
Corrosion Products ◽  
Physical Parameters ◽  
Atmospheric Conditions ◽  
The Impact

Field tests of atmospheric corrosion [7, 14, 15] are understood as investigation that are carried out in the Earth atmosphere at the ambient temperature in order to determine corrosion resistance of metals and pollution of environment by corrosion products, efficiency of corrosion protection or corrosion aggressiveness of environment [9, 11]. The investigation dedicated to prolongation of the technical service time of aircrafts as well implementation of their operation according to their actual technical condition are closely connected to investigation of corrosion processes under natural atmospheric conditions where specimens of materials are exposed to the impact of ambient factors and periodically subjected to tests that assume visual inspection, scheduled determination of weight and volume loss due to corrosion, appearance of specimens and alteration of their physical parameters [4]. Investigation results are obtained as measurements of weight and thickness of corroded specimens, photographs of specimen surfaces after withdrawing them back from the corrosion stations and removing corrosion products. On the basis of information acquired from investigations on corrosion it is possible to calculate parameters that are specific for the corrosion process that takes place within the region where a permanent corrosion station is located. The calculated parameters have been sourced from standards that are effective in Poland and worldwide [5, 6, 8, 10] but own specifications have also been developed based on the gained experience (Table 3). The research process involves also monitoring of atmospheric conditions that exist on the area where corrosion specimens are exposed [4]. Information related to atmospheric conditions is sourced from the Hydrometeorological Centre of Polish Army along with information that is published on the Internet by the Inspectorate of Environmental Protection. These information that reflect the atmospheric conditions make it possible to seek for the correlation between the parameters that are specific for the corrosion process and meteorological conditions.

Galactic orbits of stars

1966 ◽  
Vol 25 ◽  
pp. 93-97
Author(s):  
Richard Woolley
Keyword(s):  
Globular Cluster ◽  
Potential Field ◽  
High Velocity ◽  
Velocity Vector ◽  
Variable Stars ◽  
The Sun ◽  
Proper Motions ◽  
Rr Lyrae ◽  
The Galaxy

It is now possible to determine proper motions of high-velocity objects in such a way as to obtain with some accuracy the velocity vector relevant to the Sun. If a potential field of the Galaxy is assumed, one can compute an actual orbit. A determination of the velocity of the globular clusterωCentauri has recently been completed at Greenwich, and it is found that the orbit is strongly retrograde in the Galaxy. Similar calculations may be made, though with less certainty, in the case of RR Lyrae variable stars.

Distance to SN 1987A and the LMC

1999 ◽  
Vol 190 ◽  
pp. 549-554
Author(s):  
Nino Panagia
Keyword(s):  
Angular Size ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Light Curves ◽  
Distance Modulus ◽  
Absolute Size ◽  
Sn 1987A

Using the new reductions of the IUE light curves by Sonneborn et al. (1997) and an extensive set of HST images of SN 1987A we have repeated and improved Panagia et al. (1991) analysis to obtain a better determination of the distance to the supernova. In this way we have derived an absolute size of the ringRabs= (6.23 ± 0.08) x 1017cm and an angular sizeR″ = 808 ± 17 mas, which give a distance to the supernovad(SN1987A) = 51.4 ± 1.2 kpc and a distance modulusm–M(SN1987A) = 18.55 ± 0.05. Allowing for a displacement of SN 1987A position relative to the LMC center, the distance to the barycenter of the Large Magellanic Cloud is also estimated to bed(LMC) = 52.0±1.3 kpc, which corresponds to a distance modulus ofm–M(LMC) = 18.58±0.05.

International determination of the total motion of the pole

1961 ◽  
Vol 13 ◽  
pp. 29-41
Author(s):  
Wm. Markowitz
Keyword(s):  
Secular Motion ◽  
The Future

A symposium on the future of the International Latitude Service (I. L. S.) is to be held in Helsinki in July 1960. My report for the symposium consists of two parts. Part I, denoded (Mk I) was published [1] earlier in 1960 under the title “Latitude and Longitude, and the Secular Motion of the Pole”. Part II is the present paper, denoded (Mk II).

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