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Optical fiber cables are materials whose core is made of silica and other materials such as chalcogenide glasses; they transmit a digital signal via light pulses through an extremely thin strand of glass. The light propagates and is being guided by the core which is surrounded by the cladding. Light travels in the optical fiber in the form of total internal reflection in the core of the fibers. The flexibility, low tensile strength, low signal loss, high bandwidth and other characteristics of optical fibers favors it for use as a delay medium in many applications. Another favorable characteristic of optical fiber delay lines is are their relative insensitivities to environmental effects and electromagnetic interferences. The immunity of optical fibers to interferences and their less weight added advantages to it for use as delay medium. Single-mode and multi-mode are the two most popular types of optical fibers. Single-mode fibers have good propagation and delay properties with a minimal loss that allows the signal to propagate in a large distance with insignificant distortion or attenuation. The percentage of power transmission of single-mode fibers is found to be higher than that of the multi-mode fibers. It is, therefore, a preferred type for use as a delay line. In this paper, relative studies of the two optical fibers modes, and the results of power input/output measurement of the two modes are presented with a view to coming up with a better type for use as a delay medium.
EN
Natural dyes of anthocyanin extract from flame tree flower (Delonix regia) and chlorophyll extract from pawpaw leaf (Carica papaya) were used as sensitizer to fabricate dye sensitized solar cell (DSSC). The photoelectrode were subjected to UV/Vis spectrophotometer to view their absorbability. The photo electrochemical performances of DSSCs obtained from I.V characteristics showed conversion efficiency, (ɳ) of 0.80 % for the dye extracts from flame tree flower (anthocyanine), with open-circuit voltage (VOC) of 0.5249 mV, short-circuit current density (Isc) of 44.6191 mA/m2 and Fill factor (FF) of 0.5837. Chlorophyll dyes extract from pawpaw leaf has VOC, Isc, FF and conversion efficiency, (ɳ) of 0.5249 mV, 16.5283 mA/m2, 0.5585 and 0.27 % respectively. The conversion efficiency for the mixed dyes (anthocyanin and chlorophyll) at ratio 1:2 is 0.23 % with VOC, Isc and FF of 0.5500 mV, 14.2750 mA/m2 and 0.5451 respectively, while the dye mixture at ratio 1:4 achieved VOC of 0.5249 mV, Isc of 18.4941 mA/m2, FF of 0.5206 and conversion efficiency (ɳ) of 0.26 %. Anthocyanine from flame tree flower dye extract had the higher conversion efficiency of 0.8 % which could be better in term of application in dye solar cell.
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