annual 2010/2011 of the croatian academy of engineering - HATZ

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34 Annual 2010/2011 of the Croatian Academy of Engineering The images show bers covered with ashes, but not completely burned (grey part of the sample). Otherwise, they would not be identiable with precision. There are also black clumps of dirt (larger shapeless pieces) For the purpose of analyzing the fuse FTIR (Fourier Transform Infra Red) specters of bers were also recorded, which might have been used in the 3 rd or 4 th century AD in our parts: cotton, ax, hemp and Spanish Broom. The resulting curves of the mentioned bers were compared with the spectrum of the fuse sample. Figure 21 Fuse spectrum After attempts of separating parts of the fuse (grey part) from the black part, which mostly contains dirt, the difference in FTIR specters was evident, although insufcient for a denite conclusion. The differences, which relate to a total of spikes, double spike at wavelength ca. 2900 cm -1 , and at 1700 cm -1 (arc) and 1540 cm -1 (spike), represent the existence of non-cellulose natural bers (wax, pectin, lignin). At rst glance that would mean it is not cotton or Spanish Broom. However, this would be acceptable only if we take into consideration special methods for ber processing, practiced after the 19 th century. It was then assumed, based on the color and SEM images, that the fuse was actually a remainder of incomplete burning process. FTIR ber specters were then recorded after burning, and it was concluded it was probably not cotton. THE APPLICATION OF SPANISH BROOM IN FUTURE In the past, natural bers were not taken into account as reinforcements for polymeric materials because of some problems associated with their use. Lack of good interfacial adhesion, low degradation temperature, properties variability depending on the quality of harvest, age and body of the plant, as well poor resistance against moisture make the use of natural ber reinforced composites less attractive than synthetic. However, the production of composites reinforced with synthetic bers and matrices (glass, carbon, aramid) requires a large amount of energy, and they are difcult to recycle or they are completely unrecyclable. Moreover, natural bers in cases of re decrease the content of toxic gases of combustion. [10]. For the past several years there has been an increase in the number of scientic studies
Annual 2010/2011 of the Croatian Academy of Engineering 35 relating to the production of Spanish Broom as raw material for composite materials [6- 8]. The advantage of Spanish Broom over ax and hemp is that it can grow in the most unfavorable limestone soil; it is resilient to draught; and once planted it can be used during a period of up to twenty years, whilst ax and hemp demand high quality soil each year. Its cultivation on rocky areas would have several benets. For the purpose of analyzing the possibility of using Spanish Broom as composite material, inborn samples were harvested in the surroundings of Šibenik. Freshly picked shoots contained up to 35% of moisture, compared with the mass of samples dried in standard conditions. Samples were tied in bundles, soaked in sea water for 21 days and then bers were separated from the remaining woody part, using a mechanical procedure. This traditional procedure of extracting Spanish Broom was compared with several contemporary processes, using NaOH, with subsequent thermal processing at 130 °C and rapid decompression. [9]. Processing would last for approximately six hours, which is signicantly less compared with water processing between 20 and 80 days. According to the latest studies of the Faculty of Textile Technology – Institute for Textile Technology and Ecology – the possibility of microwave processing is currently undergoing research. According to present and promising results, total maceration period was reduced to 10 minutes, with a signicant decrease in the use of applied chemicals. Figure 22 Energy for production of some bers Energy for production of Spanish Broom depends on the type of applied maceration and ranges within the framework of other natural bers, according to our research. Cotton Flax Hemp Spanish broom Tensile strength (MPa) 300-700 500-900 310-750 750 Figure 23 Some natural bers properties Spanish Broom bers were extracted from the plant’s branches harvested in Dalmatia (Šibenik area) which contained 35 % of moisture compared with branches dried under
Page 1: ANNUAL 2010/2011 OF THE CROATIAN AC
Page 4 and 5: Published by Croatian Academy of En
Page 6 and 7: Mario Žagar, Ivica Crnkovi, Darko
Page 8 and 9: 8 2011 Annual 2010/2011 of the Croa
Page 10 and 11: 10 Annual 2010/2011 of the Croatian
Page 20 and 21: 20 CONCLUSION Annual 2010/2011 of t
Page 42 and 43: 42 LUBRICANTS Annual 2010/2011 of t
Page 50 and 51: 50 Typical example of Commands’ r
Page 60 and 61: 60 distant video presence on re rem
Page 72 and 73: 72 References Annual 2010/2011 of t
Page 82 and 83: 82 Bidlingmaier et al. (1999) Ziehm
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84 Annual 2010/2011 of the Croatian
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100 Annual 2010/2011 of the Croatia
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122 5.0 Conclusion 6.0 References A
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124 2 The Community of Raša Annual
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178 4 EXPERIMENTAL EVALUATION Annua
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194 and lubricant. Annual 2010/2011
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206 4 Results and discussion Annual
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Podupirajui lanovi: Arhitektonski f
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