Growth type and motor performance in schoolboys - an international comparison

The aim of the present study was to compare the growth type of 10-13-year-old non-athletic children living in different geographical regions, namely in Cyprus, Egypt, Hungary and Malaysia. Altogether 2,050 volunteer youngsters with less than 25% body fat content were investigated. Body build was estimated by the metric and plastic indices (Conrad 1963), and their cardiorespiratory endurance was assessed by the time of a 1,200 m run. The Hungarian boys were the tallest, and the Egyptians were the smallest, consistently. However, no consistent differences could be observed between the body mass means. The Hungarian boys could be characterised by the most negative metric index means, and the Cypriots were the most picnomorphs. Excluding the significant height differences from the variability of plastic index the consistent differences have disappeared. The most negative metric index means were found at 12 years of age in the Chinese, Cypriot and Egyptian samples, and the average metric indices have become greater consistently at the 13-year-old boys. The mean trend of growth type indices in Hungarian subjects has indicated a significant decrease in accordance with the data published earlier. By the cardiorespiratory endurance the subjects can be divided in two groups. Significantly better performances refer to the Cypriot and Hungarian subjects. The growth type indices introduced by Conrad (1963) sensitively reveal the slight differences in body built and physique resulting from ethnic differences, various physical activity, etc

Anthropometry and competitive sport in Hungary

Sport anthropometry has developed from the techniques and results of general physical anthropology. Thus, in the beginning, the main questions and methods were also similar to those of general physical anthropology, only the investigated subjects were taken of a different population. Following the initial, mainly descriptive and comparative, phases of data manipulation, the predictive functions of sport anthropometry have also developed. Continuous progress in the methods of sport training, consequently in athletic performances and the changes in athletic rules and equipment, have developed a need for the investigation of such (indirect) human biological factors that may have a role in competitive sport performance. The analytical approach in sport anthropometry has only become dominant during the past 10 years. A clear recognition of the relationship between structural characteristics and functions can &endash; beyond the scientific importance of the matter &endash; help sports practice in both the selection of talented youngsters and the process of athletic preparation. The most recent tendencies in sport anthropometry attempt to answer such questions that cannot be connected to the direct and traditional measurements of physical anthropology. An analysis of the relationship between inherited characteristics (physique and metabolic pathways, functional regulation during exercise, etc.) means a new challenge for sport anthropometry

Mechanical and thermal induced phase transformations in superduplex stainless steel

The aim of this work is to study the microstructural changes in SAF 2507 type superduplex stainless steel due to heat treatments and mechanical fatigue process. Specimens were heat treated in the 400-1360 °C temperature range for 1 and 5 hours respectively. An other series of specimens were periodically loaded by using a fatigue testing machine. The microstuctural changes were investigated by using a complex micromagnetic measuring system which includes a Barkhausen noise measuring and a magnetic harmonic analysing system. The RMS value of the Barkhausen noise, the distortion factor (k), and magnetic coercivity values were measured. The microstuctural changes were investigated by metallography using scanning electron microscope

Synthesis of Zinc Ferrites in RF Thermal Plasma Reactor

Formation of nanosized zinc ferrite spinels was studied from iron- and zinc oxide powders and corresponding nitrate solutions, respectively in a radiofrequency thermal plasma reactor. From the viewpoint of applications, the research was motivated by the potential use of these materials in advanced magnetic devices on the one hand, and by their biomedical applications such as drug carriers or agents for cancer treatment by hyperthermia on the other. In this work effects of synthesis conditions on properties of products were studied in details. The products were characterised for chemical composition, phase conditions, particle size distribution, morphologies and saturation magnetisation. Most products exhibited ferrimagnetic behaviour. Correlations among domain- and particle sizes were also investigated. Conditions for the synthesis of nanosized, inverse zinc ferrites of high saturation magnetisation were established. It was proved that in thermal plasma conditions normal and inverse ferrites could be produced in a single step process

Synthesis of Spinel Ferrites in Radiofrequency Thermal Plasma Reactor

Formation of nanosized zinc-ferrites and nickel-zinc ferrites from iron- and zinc oxide powders and corresponding nitrate solutions, respectively, was studied in RF thermal plasma conditions. The products were characterized for chemical composition, phase conditions, particle size distribution, morphologies and saturation magnetization. Effects of synthesis conditions on properties of products were studied in details