scholarly journals V.—The Relative Age of Flints

1893 ◽  
Vol 10 (7) ◽  
pp. 315-317
Author(s):  
A. J. Jukes-Browne
Keyword(s):  
Relative Age ◽  
Separation Product

Mr. G. Abbott is quite right in saying (Geol. Mag. for June, p. 275) that much work has yet to be done before we understand the formation of flints, and I would add that the work required must include observations on other siliceous concretions such as chert and cherty nodules of all kinds. It is also unquestionably important that we should, if possible, ascertain whether such concretions were formed contemporaneously with the deposits in which they are now found, or whether they are a sort of separation product formed during the consolidation of the rock after upheaval above the sea.

PROVENANCE, TEXTURE, AND RELATIVE AGE CONTROLS ON THE CHEMICAL INDEX OF ALTERATION (CIA) IN PLEISTOCENE TILLS, MINNESOTA USA

2018 ◽  
Author(s):  
Chad Wittkop ◽  
◽  
Christian Piper ◽  
Julie K. Bartley ◽  
Russell Krueger ◽  
...  
Keyword(s):  
Relative Age ◽  
Chemical Index ◽  
Chemical Index Of Alteration

scholarly journals Differences on Motor Competence in 4-Year-Old Boys and Girls Regarding the Quarter of Birth: Is There a Relative Age Effect?

Children ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 141
Author(s):  
Rubén Navarro-Patón ◽  
Víctor Arufe-Giráldez ◽  
Alberto Sanmiguel-Rodríguez ◽  
Marcos Mecías-Calvo
Keyword(s):  
Age Effect ◽  
Manual Dexterity ◽  
Motor Competence ◽  
Relative Age ◽  
Relative Age Effect ◽  
Two Factors ◽  
Movement Assessment ◽  
Gender Factor ◽  
Main Effects ◽  
Total Test

The aim of this study was to evaluate the differences on motor competence between boys and girls aged 4 years old and investigate the existence of Relative Age Effect on their motor competence. In total, 132 preschool children were evaluated, of whom 60 (45.50%) were girls and 72 (54.5%) were boys. The distribution of the participants was from quarter 1 [n = 28 (21.2%)], quarter 2 [n = 52 (39.4%)], quarter 3 [n = 24 (18.2%)], and quarter 4 [(n = 28 (21.2%)], respectively. The Movement Assessment Battery for Children-2 (MABC-2) was used to collect the data. The data show the main effects on quarter of birth factor in manual dexterity (MD; p < 0.001), in aiming and catching (A&C; p < 0.001), in balance (Bal; p < 0.001) and in total test score (TTS; p < 0.001). There are also statistical differences on gender factor in MD (p < 0.001) and in TTS (p = 0.031). A significant effect was also found in the interaction between two factors (gender and quarter of birth) in MD (p < 0.001), A&C (p < 0.001), and Bal (p < 0.001). There are differences in all the variables studied according to the quarter of birth and only in manual dexterity and in the total score if compared according to gender (the scores are higher in girls).

scholarly journals Estimation of the Age of Architectural Heritage Objects by Microstructural Changes of Calcite in Lime Mortars of Ancient Brickwork and Masonry

Buildings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 240
Author(s):  
Vladimir Kotlyar ◽  
Victoria Pishchulina ◽  
Alexey N. Beskopylny ◽  
Besarion Meskhi ◽  
Yury Popov ◽  
...  
Keyword(s):  
18Th Century ◽  
Degree Of Crystallinity ◽  
Architectural Heritage ◽  
Natural Conditions ◽  
Relative Age ◽  
Lime Mortars ◽  
Powder Samples ◽  
Diffraction Patterns ◽  
Cultural Monuments ◽  
The Degree Of Crystallinity

Determining the age of ancient architectural and cultural monuments is a significant scientific problem. An approach based on the transformation of portlandite into calcite and subsequent recrystallization of calcite is considered, which allows for estimating the relative age of ancient brickworks for local groups of historic buildings based on the results of diffraction studies of powder samples of carbonate mortars and measurements of samples with a known age. This article presents the results of the study of lime mortars of ancient brickwork. Under natural conditions, the process of transformation of portlandite into calcite takes from 100 to 200 years. The rate of this process is influenced by temperature, humidity, peculiarities of interaction with carbon dioxide contained in the air, etc. Examples show that portlandite is completely transformed into calcite in masonry mortars of the 18th century and that portlandite is not found in older mortars. It was determined that after the transformation of portlandite into calcite, an increase in the degree of recrystallization of calcite is observed, which manifests itself in powder diffraction patterns in the relative broadening of the diffraction peak of calcite hkl 104. In a detailed study, an estimate of the peak width at half maximum (FWHM) associated with the degree of crystallinity is effective. The actual data are given, which show that in older lime mortars the degree of recrystallization of calcite is higher than in younger ones. This fact makes it possible to indirectly determine the relative age of brickwork and masonry of various buildings of architectural heritage, which is especially relevant for the objects with the use of lime mortars of the northern provinces of the Byzantine Oecumene and other periods of various cultures.

scholarly journals Gender Differences on Motor Competence in 5-Year-Old Preschool Children Regarding Relative Age

2021 ◽  
Vol 18 (6) ◽  
pp. 3143
Author(s):  
Rubén Navarro-Patón ◽  
Joaquín Lago-Ballesteros ◽  
Víctor Arufe-Giráldez ◽  
Alberto Sanmiguel-Rodríguez ◽  
Carlos Lago-Fuentes ◽  
...  
Keyword(s):  
Preschool Children ◽  
Motor Competence ◽  
First Semester ◽  
Relative Age ◽  
Percentile Score ◽  
Relative Age Effect ◽  
Main Effect ◽  
Movement Assessment ◽  
Gender Factor ◽  
Total Test

The aim of this study was to evaluate the differences on motor competence between 5-year-old boys and girls and to investigate the existence of Relative Age Effect (RAE) on their motor competence. A total of 232 preschool children were evaluated of whom 134 (57.8%) were boys and 98 (42.2%) were girls. The Movement Assessment Battery for Children-2 (MABC-2) was used to collect data. The data show a main effect on gender factor; there was a main effect in total score of manual dexterity (MD; p = 0.010), in total score of balance (Bal; p < 0.001), in total test score (TTS; p < 0.001), and in total percentile score (TPS, p < 0.001). In the semester of birth factor, there were differences in aiming and catching (A&C, p < 0.001), in Bal (p = 0.029) and in total percentile score (TPS, p = 0.010). Girls perform better in MD, Bal, TTS, and TPS than boys. Preschool children born in the first semester obtain, in general, a higher percentage and a higher percentile than their peers born in the second one. RAE is present in A&C, Bal, and TPS, with higher scores obtained by preschool children born in the first semester compared to those born in the second one.

scholarly journals Recovery of Cenospheres and Fine Fraction from Coal Fly Ash by a Novel Dry Separation Method

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3576
Author(s):  
Jan Wrona ◽  
Witold Żukowski ◽  
Dariusz Bradło ◽  
Piotr Czupryński
Keyword(s):  
Fly Ash ◽  
Coal Fly Ash ◽  
Fine Fraction ◽  
Free Fall ◽  
Raw Material ◽  
Fluidised Bed ◽  
Air Chamber ◽  
Pneumatic Separation ◽  
Bed Separation ◽  
Separation Product

Aluminosilicate microspheres are a valuable fraction of coal fly ash with diverse applications due to their low density. Currently, there is no efficient and ecologically rational method of cenosphere recovery from fly ash. A combination of dry methods for the recovery of both fine ash particles and aluminosilicate microspheres from coal fly ash is presented. It is comprised of fluidised bed separation followed by screening and pneumatic separation in a free-fall air chamber. Fluidised bed separation was assisted by a mechanical activator to prevent agglomeration. This step reduced the portion of material that required further treatment by 52–55 wt.%, with the recovery of microspheres exceeding 97%. Then, the concentrates were individually subjected to pneumatic separation. The final separation product for the fly ash containing 0.64 wt.% cenospheres was a cenosphere concentrate that constituted about 17 wt.% of the initial fly ash. The recovery of cenospheres was around 81%. Usage of a combination of dry methods allowed for maintaining almost 83 wt.% of the raw material in its dry form. Furthermore, the produced fly ash grain fractions could be used for different industrial purposes.

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