scholarly journals Copper Corrosion in Ultrasound Cavitation Field

2021 ◽  
Vol 44 (3) ◽  
pp. 31-35
Author(s):  
Cristian Ștefan DUMITRIU ◽  
Alina BĂRBULESCU
Keyword(s):  
Mass Loss ◽  
Statistical Methods ◽  
Experimental Setup ◽  
Copper Corrosion ◽  
Cavitation Field ◽  
Ultrasound Generator

This article contains the results of the experiments concerning the mass loss of copper in seawater, in the cavitation presence. The cavitation is produced by ultrasound in an experimental setup designed for this purpose. The models of mass loss are provided and validated by statistical methods. Gravimetric indices are computed, to compare the mass loss in different cases. Differences are noticed in the mass-loss trend at different power of the ultrasound generator.

scholarly journals RBF Model for the Mass Loss of a Brass in Cavitation Field

2021 ◽  
Vol 44 (4) ◽  
pp. 17-21
Author(s):  
Alina BĂRBULESCU ◽  
Cristian Ștefan DUMITRIU
Keyword(s):  
Mass Loss ◽  
High Frequency ◽  
Saline Water ◽  
Ultrasonic Cavitation ◽  
The Third ◽  
Data Collecting ◽  
Cavitation Field ◽  
Frequency Generator ◽  
Brass Sample ◽  
High Frequency Generator

This article aims at presenting the model of the mass loss of a brass sample in ultrasonic cavitation field in saline water. The experiments done for data collecting was performed in three scenarios. In the first one, the high frequency generator worked at three power levels - 80 W, at the second one - at 120 W, and in the third one - at 180 W. The Model has been built using the series of the mass loss on surface.

Copper corrosion behaviour in acidic sulphate media in the presence of 5-methyl-1H-benzotriazole and 5-chloro-1H-benzotriazole

2015 ◽  
Vol 0 (0) ◽  
Author(s):  
Zaklina Z. Tasic ◽  
Milan M. Antonijevic
Keyword(s):  
Mass Loss ◽  
Acidic Medium ◽  
Open Circuit Potential ◽  
Corrosion Behaviour ◽  
Open Circuit ◽  
Chloride Ions ◽  
Copper Corrosion ◽  
Potentiodynamic Polarisation ◽  
Sulphate Media ◽  
Acidic Sulphate

AbstractThe influence of 1H-benzotriazole, 5-methyl-1H-benzotriazole and 5-chloro-1H-benzotriazole on copper corrosion in an acidic sulphate medium was studied, as well as the influence of chloride ions on the corrosion behaviour of copper. The methods used were potentiodynamic measurements, open circuit potential and mass loss. The results show that the examined compounds possess good inhibitory properties in an acidic medium. The potentiodynamic polarisation results indicate that the degree of copper protection against corrosion depends on the concentration of Cl

Inhibition of copper corrosion in cooling seawater under flowing conditions by novel pyrophosphate

RSC Advances ◽  
2015 ◽  
Vol 5 (79) ◽  
pp. 64326-64334 ◽  
Author(s):  
M. A. Deyab ◽  
R. Essehli ◽  
B. El Bali
Keyword(s):  
Mass Loss ◽  
Electrochemical Methods ◽  
Copper Corrosion

The inhibition of copper corrosion in cooling seawater by novel pyrophosphate molecule SrNiP2O7 (SNP) was investigated under flowing conditions using mass-loss and electrochemical methods.

scholarly journals On the Corrosion of Two Types of Bronzes Under Cavitation

2021 ◽  
Vol 44 (4) ◽  
pp. 12-16
Author(s):  
Cristian Ștefan DUMITRIU
Keyword(s):  
Mass Loss ◽  
High Frequency ◽  
Experimental Conditions ◽  
Cavitation Field ◽  
Frequency Generator ◽  
Loss Models ◽  
High Frequency Generator

This article contains the results of the experiments concerning the mass loss of two types of bronze in seawater in the cavitation produced by ultrasound generated by a high-frequency generator. The mass loss models are presented for the experimental conditions when the generator worked at different powers - 80 W, 120 W, and 180 W. In all scenarios, the results show that the bronze with Sn has the highest mass loss in the cavitation field.

Statistics and parallaxes

1978 ◽  
Vol 48 ◽  
pp. 7-29
Author(s):  
T. E. Lutz
Keyword(s):  
Experimental Design ◽  
Statistical Methods ◽  
Review Paper ◽  
Systematic Errors ◽  
Past Experience ◽  
Random Errors ◽  
Trigonometric Parallaxes ◽  
Systematic And Random Errors

This review paper deals with the use of statistical methods to evaluate systematic and random errors associated with trigonometric parallaxes. First, systematic errors which arise when using trigonometric parallaxes to calibrate luminosity systems are discussed. Next, determination of the external errors of parallax measurement are reviewed. Observatory corrections are discussed. Schilt’s point, that as the causes of these systematic differences between observatories are not known the computed corrections can not be applied appropriately, is emphasized. However, modern parallax work is sufficiently accurate that it is necessary to determine observatory corrections if full use is to be made of the potential precision of the data. To this end, it is suggested that a prior experimental design is required. Past experience has shown that accidental overlap of observing programs will not suffice to determine observatory corrections which are meaningful.

Water accumulation as a function of temperature on specimens in an electron microscope cold stage

1986 ◽  
Vol 44 ◽  
pp. 114-115 ◽  
Author(s):  
M.K. Lamvik ◽  
D.A. Kopf ◽  
S.D. Davilla ◽  
J.D. Robertson
Keyword(s):  
Electron Microscope ◽  
Mass Loss ◽  
Liquid Helium ◽  
Liquid Nitrogen ◽  
Liquid Nitrogen Temperature ◽  
Liquid Helium Temperature ◽  
Helium Temperature ◽  
Cold Stage ◽  
Water Accumulation ◽  
Better Than

Last year we reported1 that there is a striking reduction in the rate of mass loss when a specimen is observed at liquid helium temperature. It is important to determine whether liquid helium temperature is significantly better than liquid nitrogen temperature. This requires a good understanding of mass loss effects in cold stages around 100K.

Electron Beam-Induced Mass Loss in Freeze-Dried Tissue and Protein Samples

1985 ◽  
Vol 43 ◽  
pp. 470-471
Author(s):  
M.E. Cantino ◽  
M.K. Goddard ◽  
L.E. Wilkinson ◽  
D.E. Johnson
Keyword(s):  
Electron Beam ◽  
Salivary Gland ◽  
Mass Loss ◽  
Counting Rate ◽  
Dose Dependence ◽  
X Ray ◽  
Large Samples ◽  
Freeze Dried ◽  
Muscle Homogenate ◽  
Large Muscle

Quantification in biological x-ray microanalysis depends on accurate evaluation of mass loss. Although several studies have addressed the problem of electron beam induced mass loss from organic samples (eg., 1,2). uncertainty persists as to the dose dependence, the extent of loss, the elemental constituents affected, and the variation in loss for different materials and tissues. in the work described here, we used x-ray counting rate changes to measure mass loss in albumin (used as a quantification standard), salivary gland, and muscle.In order to measure mass loss at low doses (10-4 coul/cm2 ) large samples were needed. While freeze-dried salivary gland sections of the required dimensions were available, muscle sections of this size were difficult to obtain. To simulate large muscle sections, frog or rat muscle homogenate was injected between formvar films which were then stretched over slot grids and freeze-dried. Albumin samples were prepared by a similar procedure. using a solution of bovine serum albumin in water. Samples were irradiated in the STEM mode of a JEOL 100C.

TEM study of a biofilm on copper corrosion

1996 ◽  
Vol 54 ◽  
pp. 220-221
Author(s):  
W. A. Chiou ◽  
N. Kohyama ◽  
B. Little ◽  
P. Wagner ◽  
M. Meshii
Keyword(s):  
Marine Bacterium ◽  
Culture Medium ◽  
Copper Alloys ◽  
Pure Copper ◽  
Localized Corrosion ◽  
Natural Seawater ◽  
Copper Corrosion ◽  
New Approach ◽  
The Past ◽  
Copper Tolerant

The corrosion of copper and copper alloys in a marine environment is of great concern because of their widespread use in heat exchangers and steam condensers in which natural seawater is the coolant. It has become increasingly evident that microorganisms play an important role in the corrosion of a number of metals and alloys under a variety of environments. For the past 15 years the use of SEM has proven to be useful in studying biofilms and spatial relationships between bacteria and localized corrosion of metals. Little information, however, has been obtained using TEM capitalizing on its higher spacial resolution and the transmission observation of interfaces. The research presented herein is the first step of this new approach in studying the corrosion with biological influence in pure copper.Commercially produced copper (Cu, 99%) foils of approximately 120 μm thick exposed to a copper-tolerant marine bacterium, Oceanospirillum, and an abiotic culture medium were subsampled (1 cm × 1 cm) for this study along with unexposed control samples.

Elemental mass loss in silicate minerals during x-ray analysis

1990 ◽  
Vol 48 (4) ◽  
pp. 804-805
Author(s):  
P.E. Champness ◽  
R.W. Devenish
Keyword(s):  
Mass Loss ◽  
Current Density ◽  
Damage Mechanism ◽  
Beam Current ◽  
Single Chain ◽  
Plagioclase Feldspar ◽  
X Ray ◽  
Alkali Ions ◽  
Structural Order ◽  
Sheet Silicate

It has long been recognised that silicates can suffer extensive beam damage in electron-beam instruments. The predominant damage mechanism is radiolysis. For instance, damage in quartz, SiO2, results in loss of structural order without mass loss whereas feldspars (framework silicates containing Ca, Na, K) suffer loss of structural order with accompanying mass loss. In the latter case, the alkali ions, particularly Na, are found to migrate away from the area of the beam. The aim of the present study was to investigate the loss of various elements from the common silicate structures during electron irradiation at 100 kV over a range of current densities of 104 - 109 A m−2. (The current density is defined in terms of 50% of total current in the FWHM probe). The silicates so far ivestigated are:- olivine [(Mg, Fe)SiO4], a structure that has isolated Si-O tetrahedra, garnet [(Mg, Ca, Fe)3Al2Si3AO12 another silicate with isolated tetrahedra, pyroxene [-Ca(Mg, Fe)Si2O6 a single-chain silicate; mica [margarite, -Ca2Al4Si4Al4O2O(OH)4], a sheet silicate, and plagioclase feldspar [-NaCaAl3Si5O16]. Ion- thinned samples of each mineral were examined in a VG Microscopes UHV HB501 field- emission STEM. The beam current used was typically - 0.5 nA and the current density was varied by defocussing the electron probe. Energy-dispersive X-ray spectra were collected every 10 seconds for a total of 200 seconds using a Link Systems windowless detector. The thickness of the samples in the area of analysis was normally 50-150 nm.

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