Flex fatigue behaviour of plastic optical fibres (POFs) with the diameters of 0.2 and 0.3 mm under different pretensions is measured with fatigue life curve by flexometer. The fatigue sensitivity coefficient is calculated by the linear fitting curve of normalised stress versus logarithm of bending cycles. The residual modulus is investigated during the flex fatigue processes. The results exhibit the exponential relationship between applied pretension and numbers of bending cycles at break. It is indicated that the flex fatigue of POFs might be sensitive with high swing angle or swing speed. There is an evident loss of modulus for two POFs with pretensions of 4 and 10% of ultimate tensile strength during 10-times bending cycles. The values of residual modulus of two POFs almost keep constant after 10-times bending cycles.
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CO2 laser treatment can increase the surface roughness of plastic optical fibres (POFs) with the diameter of 0.5 mm and enhance the input intensity and attenuation coefficient accordingly, which is supposed to weaken the side emission of POFs in long distance above 375 mm. TiO2 particles were applied to improve the increasing optical loss of POFs by laser treatment. POFs were first modified with fine TiO2 particles and then treated by CO2 laser with the pixel time from 30 to 120 ìs. The surface morphology was observed by scanning electron microscopy to investigate the changes of micro-structure before and after laser treatment and the distribution of TiO2 particles. The illumination intensity and attenuation coefficient were calculated and compared in two methods. It is visible that the evaluation by model LLF2 with two parts is more suitable for the fitting of experimental data and shows higher input intensity and lower attenuation than that by standard power function. Both the evaluation methods exhibit that the utilization of TiO2 particles could play an active role in the enhancement of side emission of POFs treated by CO2 laser.
3
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In this contribution selected physical and mechanical properties of laboratory prepared basalt filaments and fibres drawn out from these are presented. The mechanical properties were investigated after tempering up to 800 °C. The ultimate strength distribution, torsional rigidity, deformation at break and sound wave spread velocity are mentioned. The thermal properties were investigated by TMA apparatus. The thermal expansion and compressive creep were measured. Analysis of a fibrous fragment evolved during the abrasion of basalt weave is presented. Basalt particles are too thick to be directly respirable, but their length/diameter ratio is higher than 3 and therefore the handling of basalt fibres must be carried out with care.
PL
W artykule opisano wybrane właściwości fizyczne, w tym mechaniczne, laboratoryjnie wyprzędzionych filamentowych włókien bazaltowych i wyciąganych z nich włókien ciętych. Badani również mechaniczne właściwości przygotowanych włókien po poddaniu ich działaniu podwyższonej do 600 °C temperatury. Badano rozkład wytrzymałość na zerwanie, dla zbiorów włókien, wydłużenie przy zerwaniu, sztywność przy skręcani i szybkość rozchodzenia się dźwięku. Właściwości termiczne, takie jak wydłużenie przy podgrzewaniu i pełzanie przy ściskaniu, były badane, za pomocą aparatu TMA. Analizowano również fragmenty włókien powstające przy obróbce. Oderwane cząsteczki włókien bazaltowych są zbyt grube aby były bezpośrednio respirowane, ale stosunek ich długości do średnicy jest wyższy niż 3 i dlatego też należy obchodzić się z włóknami bazaltowymi z należytą ostrożnością.
4
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The basic techniques for evaluation of spatial autocorrelation indices are discussed. The local Gi, statistics are described and their connection with global Moran index is shown. These statistics are used for estimation of variation of air permeability of clean room textile ARGOS. The analysis of planar uniformity based on the coefficient of variation decomposition is realized as well.
5
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The basic properties of bast fibers are discussed with respects of differences between flax and hemp fibers. The main part is devoted to description of influence of enzymatic cottonization on the selected mechanical properties of ultimate flax fibers. For characterization of ultimate strength the Weibull distribution is used. The initial modulus and deformation work are estimated from experimental data.
6
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The main aim of this contribution is description of influence of enzymatic cottonization on the selected geometrical properties of ultimate flax fibers. For characterization of cross section shape changes the shape factor is used. The fineness is computed from area of cross section and gravimetric measurements. The length distribution of ultimate flax fibers is characterized by the robust median measure. The frequency of bundles exceeding some limit sizes are computed.
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