Determination of the chemical nonuniformity of distribution of elements in P/M materials

1982 ◽  
Vol 21 (2) ◽  
pp. 133-136
Author(s):  
V. N. Antsiferov ◽  
N. N. Maslennikov ◽  
S. N. Peshcherenko ◽  
A. I. Rabinovich
Keyword(s):  
Distribution Of Elements ◽  
Chemical Nonuniformity

High Temperature Corrosion of Evaporator Tubes with Thermal Sprayed Coatings

2010 ◽  
Vol 165 ◽  
pp. 110-117
Author(s):  
Jerzy Łabanowski ◽  
J. Ćwiek
Keyword(s):  
Cross Sections ◽  
Molten Salts ◽  
Single Layer ◽  
Steam Boiler ◽  
Low Emission ◽  
Distribution Of Elements ◽  
One Year ◽  
Sprayed Coatings ◽  
Thermal Sprayed Coatings

Degradation examinations of outer surface of low-emission steam boiler evaporator tubes are presented in the paper. Metallographic evaluation of scale morphology as well as determination of chemical composition of micro sites and distribution of elements on cross-sections is reported. Water-wall tubes were exposed in steam boiler for up to two years period. Common tubes produced from 16Mo3 steel suffered sulphide and molten salts corrosions. Thermal sprayed tubes with the single layer of 70%Ni 30%Cr alloy demonstrate better corrosion resistance, but become susceptible to sulphide corrosion due to presence of internal voids and cracks. Double layer Al2O3/Ni-30Cr coatings withstood corrosion attack for more than one year of operation, and then failed due to internal heterogeneity and crack generation.

Distribution of trace elements in the lipid and nonlipid matter of hair

1990 ◽  
Vol 36 (3) ◽  
pp. 477-480 ◽  
Author(s):  
K M Attar ◽  
M A Abdel-Aal ◽  
P Debayle
Keyword(s):  
Trace Elements ◽  
Inductively Coupled Plasma ◽  
Lipid Fraction ◽  
Soxhlet Extraction ◽  
The Body ◽  
Clinical Aspects ◽  
Inductively Coupled ◽  
Distribution Of Elements ◽  
Hair Fiber

Abstract We studied the effect of lipid removal on the concentrations of 13 trace elements measured in human hair. We used a pooled specimen of hair from a barber shop, initially washed with de-ionized water, with ultrasonic cleaning, then analyzed for Ca, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Si, Sr, and Zn with use of an inductively coupled plasma emission spectrometer. The lipid was removed by Soxhlet extraction with ethanol, and the hair was re-analyzed. We found several elements present in a relatively large proportion (greater than 20%) in the lipid fraction, mainly Na, K, Ca, Mg, Ni, and Sr. We suggest that removal of part or all of the lipids from hair by using detergents or other lipid-removing solvents for washing may account for the variability in data on elements in hair reported by different laboratories, and that those elements largely present in the lipid fraction are the result of environmental exposure, whereas those retained in the hair fiber after lipid removal can be attributed to nutritional and clinical aspects. We believe that such determination of the distribution of elements may help validate the use of hair in assessing trace elements in the body.

scholarly journals Where are the Atoms in Quasicrystals? Experimental and Theoretical Studies of Ternary and Quaternary Approximants

2000 ◽  
Vol 643 ◽  
Author(s):  
Gordon J. Miller ◽  
Chi-Shen Lee ◽  
Wen-Jiuan Tsai
Keyword(s):  
Theoretical Model ◽  
Electron Concentration ◽  
Valence Electron ◽  
Valence Electron Concentration ◽  
Theoretical Studies ◽  
Distribution Of Elements ◽  
Experimental And Theoretical Studies ◽  
Li Content

AbstractProblems concerning complete structural characterization of quasicrystals involve locating the atomic positions as well as determining the distribution of elements at each site. Quasicrystalline approximants provide models for potential building units of quasicrystals, but a clear determination of the elementaldecorations in such approximants also remains incomplete. We report experimental and theoretical studies of new, quaternary Bergman phases in the Li-Mg-Zn-Al system and a new, quasicrystalline approximant Li10Mg6Zn31Al3 (A16M34-type). A theoretical model using averaged Mulliken populations provides a means to track the segregation of elements (and vacancies) onto different sites as a function of valence electron concentration. As the Li content decreases, vacancies begin to occur at a specific site in the Bergman structure. The new approximant demonstrates how truncated tetrahedra can play an important role in forming clusters with possible fivefold symmetry in quasicrystalline structures.

scholarly journals Selected Tribological Properties of A390.0 Alloy

2017 ◽  
Vol 17 (4) ◽  
pp. 175-178 ◽  
Author(s):  
R. Wieszała ◽  
J. Piątkowski
Keyword(s):  
Internal Combustion Engines ◽  
Internal Combustion ◽  
Operating Conditions ◽  
Combustion Engines ◽  
New Materials ◽  
Surface Distribution ◽  
Distribution Of Elements ◽  
Piston System ◽  
Pin On Disc

AbstractEmergence of new designs for internal combustion engines resulted in a necessity to search for new materials which will rise to excessive technological requirements under operating conditions of modern internal combustion engines of up to 150 kW. Focusing only on material properties, theoretically existing alloys should meet presents requirements. More importantly, existing materials are well fitted to the entire crank-piston system. Thus, there is a need for a more thorough examination of these materials. The paper presents studies on determination of coefficient of friction μ and wear for the A390.0 alloy modified with AlTi5B master alloy combined with EN GJL-350 cast iron. The characteristics of a T-11 tribological tester (pin on disc) used for the tests, as well as the methodology of the tribological tests, were described. Also, the analysis of the surface distribution of elements for the pin and the disc was presented. The studies were realized in order to find whether the analyzed alloy meets the excessive requirements for the materials intended for pistons of modern internal combustion engines. The results show that the A390.0 alloy can only be applied to a load of 1.4 MPa. Above this value was observed destructive wear, which results in the inability to use it in modern internal combustion engines.

Determination of the distribution of elements with similar electron counts: a practical guide for resonant X-ray scattering

2013 ◽  
Vol 46 (3) ◽  
pp. 769-778 ◽  
Author(s):  
Simon Welzmiller ◽  
Philipp Urban ◽  
Felix Fahrnbauer ◽  
Loredana Erra ◽  
Oliver Oeckler
Keyword(s):  
Element Distribution ◽  
Data Sets ◽  
Data Set ◽  
X Ray ◽  
X Ray Scattering ◽  
Multiple Data ◽  
Straightforward Method ◽  
Distribution Of Elements ◽  
Ray Scattering

This article attempts to present straightforward and easy-to-understand guidelines for the determination of element distribution in compounds lacking X-ray scattering contrast because they have similar electron counts. Different sources of anomalous dispersion correction terms (especially Δf′ values) are compared with respect to their suitability, reliability and quality. Values from databases are compared with Δfvalues calculated from fluorescence spectra and those refined from single-crystal diffraction data, using both reference crystals without scattering contrast problems and crystals containing elements with similar electron counts. The number of data sets required to determine reliably the element distribution and the optimum wavelengths to be used are discussed. Joint multiple data set refinements are suitable for the refinement of multiply mixed occupancies of elements lacking scattering contrast. The most straightforward method of obtaining Δf′ values depends on the complexity of the problem to be solved and the precision required.

Determination of the chemical nonuniformity of cellulose acetate

1989 ◽  
Vol 21 (2) ◽  
pp. 104-106
Author(s):  
E. A. Nekhaenko ◽  
L. S. Gembitskii ◽  
L. N. Verkhotina ◽  
V. I. Ismakova ◽  
N. L. Kuz'mina ◽  
...  
Keyword(s):  
Cellulose Acetate ◽  
Chemical Nonuniformity

Determination of the distribution of elements as a function of particle size in aerosol samples by sequential leaching†

The Analyst ◽  
1998 ◽  
Vol 123 (5) ◽  
pp. 859-863 ◽  
Author(s):  
József Hlavay ◽  
Klára Polyák ◽  
Ernö Mészáros
Keyword(s):  
Particle Size ◽  
Sequential Leaching ◽  
Distribution Of Elements
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