Efficiency of Sample Transport from the Electrode Cavity to the Excitation Zone of Gas-Stabilized dc Arcs for Spectrochemical Analysis

1970 ◽  
Vol 24 (2) ◽  
pp. 241-245 ◽  
Author(s):  
P. W. J. M. Boumans ◽  
F. J. M. J. Maessen
Keyword(s):  
Lithium Carbonate ◽  
Test Sample ◽  
Line Intensities ◽  
Excitation Region ◽  
Lithium Metaborate ◽  
Test Elements ◽  
And Control ◽  
Dc Arc ◽  
Silicate Sample

The transfer of atomized material from the electrode cavity to the discharge region of a dc arc is quantitatively defined in terms of the efficiency with which elements enter the excitation region. Equations inherent in the determination of efficiencies from spectral-line intensities are given. Relative efficiencies were experimentally determined for a synthetic silicate sample containing some 20 test elements as trace or minor constituents. The elements were selected according to volatility and carbide forming properties. The influences of the following variables on the efficiency were investigated: (a) type of element, (b) preliminary fusion of test sample with lithium metaborate, (c) dilution of test sample with lithium carbonate or lithium fluoride, (d) two different types of Stallwood-jet devices for arc stabilization and control of atmosphere, (e) the composition of the stabilizing gas, viz., the oxygen content of an oxygen—argon gas mixture, and (f) the flow rate of the stabilizing gas.

Spectrographic Determination of Calcium in Latex of Natural Rubber (Hevea Brasiliensis)

1970 ◽  
Vol 24 (6) ◽  
pp. 583-587 ◽  
Author(s):  
S. K. Ng ◽  
R. C. H. Hsia ◽  
P. T. Lai
Keyword(s):  
Natural Rubber ◽  
Atomic Absorption ◽  
Hevea Brasiliensis ◽  
Internal Standard ◽  
Lithium Carbonate ◽  
Cathode Layer ◽  
Spectrographic Determination ◽  
Dc Arc

A cathode layer dc arc method of determining microgram amounts of calcium in latex of Hevea brasiliensis is described. Using lithium carbonate and lanthanum sulphate as buffers, a working curve covering 0.032% to 10.0% Ca in ash of latex can be constructed with palladium as internal standard. Phosphate and silica suppress Ca emission but silica has a considerably greater effect. Of the four matrices examined, the composition with 44.7% K2O, 22.3% P2O5, and 13.4% MgO, which is most representative of the composition of latex ash, gives reproducible Ca values and these are in closest agreement with those obtained by atomic absorption. The spectrographic technique may be extended to simultaneously determine trace amounts of Mn, Fe, Cu, and Si.

Rapid Determination of Bismuth and Lead in Iron- and Nickel-Base Alloy Chips

1973 ◽  
Vol 27 (6) ◽  
pp. 464-466 ◽  
Author(s):  
M. G. Atwell ◽  
G. S. Golden
Keyword(s):  
Base Alloy ◽  
Rapid Determination ◽  
Lithium Carbonate ◽  
Nickel Base Alloy ◽  
Precision And Accuracy ◽  
Single Standard ◽  
Nickel Base ◽  
Dc Arc ◽  
Accuracy Data

A rapid emission spectographic method for the determination of traces of bismuth and lead in a wide variety of iron- and nickel-base alloys is reported. The sample, in the form of chips, filings, or drillings, is mixed with lithium carbonate, placed in an anode cup electrode, and excited in a dc arc. Detection limits of approximately 0.2 ppm for bismuth and 0.4 ppm for lead may be realized, depending on the alloy. Working curves may be prepared from a single standard of each alloy by using variable weights in a series of electrodes. Precision and accuracy data for a number of alloys are presented.

Effect of External Magnetic Field on the Volatilization of Elements in the dc Arc

1978 ◽  
Vol 32 (3) ◽  
pp. 272-275 ◽  
Author(s):  
A. A. Fakhry ◽  
M. A. Eid ◽  
M. S. Hashem
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Magnetic Fields ◽  
Spectral Line ◽  
Spectral Lines ◽  
Line Intensities ◽  
Carbon Arc ◽  
Dc Arc ◽  
The Magnetic Field ◽  
Silicate Sample

In the present investigation opposing magnetic fields are applied to the free burning carbon arc with a silicate sample (granodiorite) in its anode crater. The magnetic field promoted the selective volatilization of the elements present in the sample. As a result, a depression in the spectral line intensities of Mn, Ti, Th, and Fe as well as the background was observed. At the same time the intensity of the spectral lines of Ag, Ge, Pb, In, and Cu is enhanced. The latter elements are of great significance since they are used as pathfinders for gold.

Ultrastructural changes in sciatic nerve tissue: Effects of passive maternal smoking

1983 ◽  
Vol 41 ◽  
pp. 650-651
Author(s):  
Amankwah K.S. ◽  
A.D. Weberg ◽  
R.C. Kaufmann
Keyword(s):  
Sciatic Nerve ◽  
Maternal Smoking ◽  
Ultrastructural Level ◽  
Uranyl Acetate ◽  
Nerve Tissue ◽  
Ultrastructural Changes ◽  
Cacodylate Buffer ◽  
And Control ◽  
Spontaneous Delivery

Previous research has revealed that passive (involuntary inhalation) tobacco smoking during gestation can have adverse effects upon the developing fetus. These prior investigations did not concentrate on changes in fetal morphology. This study was undertaken to delineate fetal neural abnormalities at the ultrastructural level in mice pups exposed in utero to passive maternal smoking.Pregnant study animals, housed in a special chamber, were subjected to cigarette smoke daily from conception until delivery. Blood tests for determination of carbon monoxide levels were run at 15-18 days gestation. Sciatic nerve tissue from experimental and control animals were obtained following spontaneous delivery and fixed in 2.5% gluteraldehyde in 0.1M cacodylate buffer pH 7.3. The samples were post-fixed in osmium ferrocyanide (1:1 mixture of 1.5% aqueous OSO4 and 2.5% K4 Fe(CN)6). Following dehydration, the tissues were infiltrated with and embedded in Spurr. Sections were stained with uranyl acetate and lead citrate.

Application of EDS Technique for OSP Film Thickness Measurement

2006 ◽  
Author(s):  
Prong Kongsubto ◽  
Sirarat Kongwudthiti
Keyword(s):  
Thin Film ◽  
Quantitative Analysis ◽  
Joint Strength ◽  
Critical Factor ◽  
Thickness Measurement ◽  
Ic Manufacturing ◽  
And Control ◽  
Film Thickness Measurement ◽  
Non Destructive

Abstract Organic solderability preservatives (OSPs) pad is one of the pad finishing technologies where Cu pad is coated with a thin film of an organic material to protect Cu from oxidation during storage and many processes in IC manufacturing. Thickness of OSP film is a critical factor that we have to consider and control in order to achieve desirable joint strength. Until now, no non-destructive technique has been proposed to measure OSP thickness on substrate. This paper reports about the development of EDS technique for estimating OSP thickness, starting with determination of the EDS parameter followed by establishing the correlation between C/Cu ratio and OSP thickness and, finally, evaluating the accuracy of the EDS technique for OSP thickness measurement. EDS quantitative analysis was proved that it can be utilized for OSP thickness estimation.

scholarly journals Biodegradation of Poly(Lactic Acid) Biocomposites under Controlled Composting Conditions and Freshwater Biotope

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 594
Author(s):  
Pavel Brdlík ◽  
Martin Borůvka ◽  
Luboš Běhálek ◽  
Petr Lenfeld
Keyword(s):  
Degradation Rate ◽  
Poly Lactic Acid ◽  
Screw Extruder ◽  
Flat Film ◽  
Twin Screw ◽  
Acetyl Tributyl Citrate ◽  
And Control ◽  
Aerobic Biodegradability ◽  
Qualitative Analyses

The influence of additives such as natural-based plasticiser acetyl tributyl citrate (ATBC), CaCO3 and lignin-coated cellulose nanocrystals (L-CNC) on the biodegradation of polylactic acid (PLA) biocomposites was studied by monitoring microbial metabolic activity through respirometry. Ternary biocomposites and control samples were processed by a twin-screw extruder equipped with a flat film die. Commonly available compost was used for the determination of the ultimate aerobic biodegradability of PLA biocomposites under controlled composting conditions (ISO 14855-1). In addition, the hydro-degradability of prepared films in a freshwater biotope was analysed. To determine the efficiency of hydro-degradation, qualitative analyses (SEM, DSC, TGA and FTIR) were conducted. The results showed obvious differences in the degradation rate of PLA biocomposites. The application of ATBC at 10 wt.% loading increased the biodegradation rate of PLA. The addition of 10 wt.% of CaCO3 into the plasticised PLA matrix ensured an even higher degradation rate at aerobic thermophilic composting conditions. In such samples (PLA/ATBC/CaCO3), 94% biodegradation in 60 days was observed. In contrast, neat PLA exposed to the same conditions achieved only 16% biodegradation. Slightly inhibited microorganism activity was also observed for ternary PLA biocomposites containing L-CNC (1 wt.% loading). The results of qualitative analyses of degradation in a freshwater biotope confirmed increased biodegradation potential of ternary biocomposites containing both CaCO3 and ATBC. Significant differences in the chemical and structural compositions of PLA biocomposites were found in the evaluated period of three months.

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