The Impact of Fatigue on the Sense of Local and Global Rhythmic Movement

Efficient movement control and the mechanisms responsible for the sense of rhythm are still not fully understood. The purpose of this paper was to estimate the influence of fatigue on the sense of rhythm defined as specific order of movements and their rhythmic perception. It was examined in a holistic way, by analyzing both global and local aspects of the movement. Twenty adult participants (20.2 ± 0.4 years, ten females) took part in the experiment. The fatigue protocol was applied in four blocks, which consisted of 30-s consecutive jumping with 80% of maximal effort. Immediately after each fatigue block, the rhythm performance was evaluated in global and local tests. The global test was based on 45 continuous jumps and was divided into an assisted and an unassisted phase using the Optojump Next System. The local test was performed by bilateral tapping of lower limbs by means of the Vienna Test System. The hypothesis about the significant effect of fatigue on the sense of rhythm was falsified. In particular, we observed the lack of differences between global and local aspects of the movement. Moreover, female participants showed a better sense of rhythm than males. Regardless of the fatigue protocol, participants made larger errors with a lower movement frequency in local rhythmic tasks. The coefficient of variation showed that sex differences were only significant in the unassisted phase of the global rhythmic task. We suggest that movement variability metrics may provide additional information about the sense of rhythm, which should be explored more in future studies, not only dependent on fatigue

THE INFLUENCE OF MICROSTRUCTURE OF 30MnB4 STEEL ON HYDROGEN-ASSISTED CRACKING

This paper analyzes the problem of susceptibility to hydrogen-assisted cracking (fracture behavior) of zinc-coated screws made of 30MnB4 steel. Two samples (screws) were compared after proper and improper heat treatment affecting hydrogen solubility during the further galvanic process and resulting in different fracture modes. Both samples were loaded to failure by torsion. The fracture surface and microstructure of the samples were examined using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS)

Comparison of gate leakage current components in metal-insulator-semiconductor structures with high-k gate dielectrics, Journal of Telecommunications and Information Technology, 2001, nr 1

Numerical simulations of the gate leakage current in metal-insulator-semiconductor (MIS) structures based on the transfer matrix approach were carried out. They show contribution of different components of this current in MIS structures with best known high-k dielectrics such as Ta2O5 and TiO2. The comparison of the gate leakage current in MIS structures with SiO2 layer as well Ta2O5 and TiO2 layers is presented as well. Additionally, the minimum Si electron affinity to a gate dielectric which allows to preserve given level of the gate leakage current is proposed

Change ofα-Particle Stopping Power in Ni at the Curie Temperature

Experiments showing that the ion-solid state interaction characteristics change at T$\text{}_{C}$, the Curie temperature, were recapitulated. It was shown that the experimental results for the increase in theα-particles stopping power in Fe and Gd foils can be approximately described by the Bethe theory of stopping power with Stoner model for band ferromagnetism. The experimental result for increase in 5.486 MeVα-particles stopping power in 0.89 mg/cm$\text{}^{2}$ Ni foil after transition from ferro- to paramagnetic phase at T$\text{}_{C}$ was presented and it was shown to be in a good correlation with the previous data and with the theoretical evaluation

Change of α-Particle Stopping Power in Ni at the Curie Temperature

Experiments showing that the ion-solid state interaction characteristics change at T$\text{}_{C}$, the Curie temperature, were recapitulated. It was shown that the experimental results for the increase in theα-particles stopping power in Fe and Gd foils can be approximately described by the Bethe theory of stopping power with Stoner model for band ferromagnetism. The experimental result for increase in 5.486 MeVα-particles stopping power in 0.89 mg/cm$\text{}^{2}$ Ni foil after transition from ferro- to paramagnetic phase at T$\text{}_{C}$ was presented and it was shown to be in a good correlation with the previous data and with the theoretical evaluation

THE EFFECT OF NON-METALLIC INCLUSIONS ON THE CRAK PROPAGATION IMPACT ENERGY OF TOUGHENED 35B2+Cr STEEL

35B2+Cr steel was designed as a material for screws. The investigations were carried out on toughened samples, taken from three ingots of 35B2+Cr steel (delivered from three various steel suppliers), and of different content of non-metallic inclusions. In each case, the fraction of non-metallic inclusions was in agreement with the corresponding standard. This study presents the results of the research focused on the influence of non-metallic inclusions on the impact energy of crack development in 35B2+Cr steel. The role of non-metallic inclusions was considered both in relation to their total fraction and in relation to the fraction of oxides, sulfides, nitrides and exogenous inclusions separately. Assuming linear dependence between notch-root radius and the impact energy of crack nucleation, basing on the impact toughness tests, the impact energy of the crack development was evaluated. It was proved, that in spite of the level of fraction of non-metallic inclusions compatible with the corresponding standards, they directly or indirectly influence the impact energy of 35B2+Cr steel. This influence depends on the character of the inclusions

BANDED MICROSTRUCTURE IN FORGED 18CrNiMo7-6 STEEL

18CrNiMo7-6 steel, after hot forging, exhibits a distinct banding of ferritic-pearlitic microstructure, probably related to the segregation of alloying elements during the ingot crystallization. The heat treatment allowing to obtain bainitic microstructure in this steel is described in the paper. The obtained bainitic microstructure exhibits only very small traces of banding

Strength and Weaknesses of Higher Education in Poland

W artykule przedstawiono udokumentowaną opinię o stanie systemu edukacji w Polsce. Oceniono pozycję Polski na tle innych krajów w oparciu o analizę indeksów narodowego potencjału intelektualnego. Wykazano stan niedofinansowania systemu kształcenia i skutki chronicznego niedofinansowania obszaru nauki. Pokazano ocenę stanu kadry nauczycieli akademickich, wpływ przeciążenia obowiązkami akademickimi na jakość kształcenia, brak jakiejkolwiek polityki rekrutacyjnej. W podsumowaniu zwrócono uwagę na konieczność podjęcia działań naprawczych.This paper presents an opinion on the state of the education system in Poland, which is based on the analysis of diverse indexes of national intellectual potential. It is shown that the education system is not financed enough and the area of science suffers from the chronic effects of underfunding. The paper presents an assessment of the state of academic staff, of the influence of an overload with academic responsibilities on the quality of education and of the lack of any recruitment policy. The summary emphasises the need to take corrective actions

Some factors influencing the determination of eutectoid transformation start and finish temperatures in hypoeutectoid steels

Tyt. z nagłówka.Bibliografia s.127-[128].Dostępny również w formie drukowanej.ABSTRACT: This paper presents problems related to the proper determination of the eutectoid transformation start and finish temperatures in steels during heating. Information from references indicate an essential influence of interlamellar spacing in pearlite on the formation of the dilatation effect related to the eutectoid transformation finish, on dilatometric curves. It was revealed, in this paper, that the appearance of the dilatation effect related to the eutectoid transformation finish in hypoeutectoid steels or its lack in the heating dilatograms depends on the resolution ability of the applied dilatometer. STRESZCZENIE: W artykule przedstawiono problemy związane z prawidłowym określeniem temperatur początku i końca przemiany eutektoidalnej w stalach podczas nagrzewania. Doniesienia literaturowe wskazują na istotny wpływ odległości międzypłytkowej w perlicie na powstawanie efektu dylatacyjnego związanego z zakończeniem przemiany eutektoidalnej na krzywych dylatometrycznych. W niniejszej pracy wykazano, że wystąpienie lub nie na dylatogramie nagrzewania efektu dylatacyjnego od końca przemiany eutektoidalnej w stalach podeutektoidalnych związane jest również ze zdolnością rozdzielczą użytego dylatometru. KEYWORDS: pearlitic transformation, dilatometric examinations, phase transformation temperatures, interlamellar spacing, hypoeutectoid steel. SŁOWA KLUCZOWE: przemiana perlityczna, temperatury przemian, badania dylatometryczne, odległość międzypłytkowa, stal podeutektoidalna