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Acta Physiologica Hungarica
Authors:
Dragan Radovanovic
,
N. Ponorac
,
A. Ignjatovic
,
N. Stojiljkovic
,
T. Popovic
, and
A. Rakovic

Race walking is the technical and athletic expression of fast walking and it can be considered as a type of endurance performance. The purpose of this study was to examine whether 12 weeks of a specially designed training program results in the further training enhancement of endurance performance and the related physiological parameters in already well-trained race walkers competing at the national and international level. The investigation protocol consisted of determining the maximal oxygen uptake (VO2peak) and related gas exchange values using an automated cardiopulmonary exercise system and of determining blood lactate variables (aerobic threshold — LTAer and the maximal lactate steady state — MLSS) during walking with proper technique at 8, 10, 12 and 14 km·h−1 for 4 minutes without rest in between. Thereafter, the speed on the treadmill was increased by 0.5 km·h−1 every two minutes until exhaustion to determine VO2peak. After 12 weeks of a specially designed endurance training, statistically significant increases in VO2peak (61.8±8.5 mL·kg−1·min-1 pre vs. 66.9±9.5 mL·kg−1·min−1 post training; p<0.05) and blood lactate variables (VO2-LTAer and VO2-MLSS; p<0.05) were noted. The obtained results suggest that the applied training program can improve endurance and race performance in previously well trained race walkers.

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Journal of Thermal Analysis and Calorimetry
Authors:
M. Feder
,
Maria Popescu
,
E. Segal
,
N. Dragoe
,
D. Crisan
, and
N. Dragan

The solid-state reaction between SrCO3 and α-FeOOH was investigated by means of thermal analysis, X-ray diffraction, electron microscopy and magnetic measurements. The high reactivity of this mixture is discussed in comparison with that of the mixture of SrCO3 and α-Fe2O3.

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Journal of Thermal Analysis and Calorimetry
Authors:
Adelina Ianculescu
,
Ana Brăileanu
,
M. Crişan
,
P. Budrugeac
,
N. Drăgan
,
G. Voicu
,
D. Crişan
, and
V. Marinescu

Abstract  

In order to obtain pure and fine BaTiO3 powders with controlled morphology, sol-precipitation methods involving the use of titanium iso-propoxide and of two different barium sources, i.e. barium nitrate and barium acetate, were proposed in this work. The thermal behaviour of the synthesized gels and the X-ray diffraction data obtained for the oxide powders pointed out that, by using Ba(NO3)2 as barium source, the decomposition process was completed at lower temperature (750C) and was accompanied by a more pronounced tendency to obtain a single phase BaTiO3 composition, by comparison with the synthesis where barium acetate was used as raw material (1100C). Scanning electron microscopy investigations emphasized the effect of the nature of barium source and synthesis conditions on the morphology of the oxide powders, as well as on the microstructure of the related ceramics.

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Journal of Thermal Analysis and Calorimetry
Authors:
Maria Crişan
,
Ana Brăileanu
,
D. Crişan
,
Mălina Răileanu
,
N. Drăgan
,
Diana Mardare
,
V. Teodorescu
,
Adelina Ianculescu
,
Ruxandra Bîrjega
, and
M. Dumitru

Abstract  

Among the great number of sol-gel materials prepared, TiO2 holds one of the most important places due to its photocatalytic properties, both in the case of powders and coatings. Impurity doping is one of the typical approaches to extend the spectral response of a wide band gap semiconductor to visible light. This work has studied some un-doped and Pd-doped sol-gel TiO2 nanopowders, presenting various surface morphologies and structures. The obtained powders have been embedded in vitreous TiO2 matrices and the corresponding coatings have been prepared by dipping procedure, on glass substrates. The relationship between the synthesis conditions and the properties of titania nanosized materials, such as thermal stability, phase composition, crystallinity, morphology and size of particles, and the influence of dopant was investigated. The influence of Pd on TiO2 crystallization both for supported and unsupported materials was studied (lattice parameters, crystallite sizes, internal strains). The hydrophilic properties of the films were also connected with their structure, composition and surface morphology. The methods used for the characterization of the materials have been: simultaneous thermogravimetry and differential thermal analysis, powder X-ray diffraction, electron microscopy (TEM, SAED) and AFM.

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