Recovering Joys Law as a Function of Solar Cycle, Hemisphere, and Longitude

Bipolar active regions in both hemispheres tend to be tilted with respect to the East West equator of the Sun in accordance with Joys law that describes the average tilt angle as a function of latitude. Mt. Wilson observatory data from 1917 to 1985 are used to analyze the active-region tilt angle as a function of solar cycle, hemisphere, and longitude, in addition to the more common dependence on latitude. Our main results are as follows: i) We recommend a revision of Joys law toward a weaker dependence on latitude (slope of 0.13 to 0.26) and without forcing the tilt to zero at the Equator. ii) We determine that the hemispheric mean tilt value of active regions varies with each solar cycle, although the noise from a stochastic process dominates and does not allow for a determination of the slope of Joys law on an 11-year time scale. iii) The hemispheric difference in mean tilt angles, 1.1 degrees + 0.27, over Cycles 16 to 21 was significant to a three-sigma level, with average tilt angles in the northern and southern hemispheres of 4.7 degrees + 0.26 and 3.6 degrees + 0.27 respectively. iv) Area-weighted mean tilt angles normalized by latitude for Cycles 15 to 21 anticorrelate with cycle strength for the southern hemisphere and whole-Sun data, confirming previous results by Dasi-Espuig, Solanki, Krivova, et al. (2010, Astron. Astrophys. 518, A7). The northern hemispheric mean tilt angles do not show a dependence on cycle strength. vi) Mean tilt angles do not show a dependence on longitude for any hemisphere or cycle. In addition, the standard deviation of the mean tilt is 29 to 31 degrees for all cycles and hemispheres indicating that the scatter is due to the same consistent process even if the mean tilt angles vary.Comment: 13 pages, 4 figures, 3 table

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Not AvailableBiochemical quality of dry fish samples of Eel, Croaker, Gold spotted anchovy, Bombay duck , Greater lizard fish, Ribbon fish, Horse Mackerel and Cat fish traditionally sun dried were collected from Veraval fish market, Gujarat during March to June, 2016. The biochemical quality parameter such as thiobarbituric acid , tri-methyl amine, total volatile base nitrogen, free fatty acid , pH and moisture content were analysed as indices of spoilage. The pH and moisture content of the samples were ranged from 5.49 to 6.92 and 9.47 to 31.92 per cent , respectively. The TBA values of the dry fish samples varied between 1.68 to 25.94 mg per malonaldehyde and all the samples had more than 2 mg of TBA number except for Greater lizard fish. The TMA values were found high in all the dried fish samples except cat fish. The TVBN values of the samples varied between 25.89 to 128.34 mg 100 per gram whereas greater than 100 mg per cent were found in Gold spotted anchovy, Bombay duck, Greater lizard fish and Mackerel. The per cent FFA values among the dry fish samples were ranged between 0.46 to 13.58 per cent. The study shows that the biochemical quality of the dry fish samples prepared under traditional sun drying condition were in good quality at the initial period of processing but good packaging and storage condition should be maintained till reach the consumers as well to maintain the shelf life of the dry fish.Not Availabl

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Not AvailableThe present study was carried out to assess the microbiological quality of traditionally dried and commercially available fish such as Eel, Croaker, Gold spotted anchovy, Bombay duck , Greater lizard fish, Ribbon fish, Horse Mackerel and Cat fish collected from in and around Veraval fish market, Gujarat during the summer months of March to June, 2016. Microbial quality parameters such as TPC, E.coli, Staphylococci, Fecal Streptococci, Salmonella, Vibriosis, Listeria monocytogenes, Total fungal and yeast count were analysed. The TPC ranged between 1.2 x 102 to 2.35 x 105 cfu.g-1. Total fungal and yeast count were found within the acceptable limit of TPC except in Bombay duck dry fish samples, wherein the count was TNTC and was exceeded the acceptable limit of 5,00,000 cfu.g-1. Moreover, there was no pathogenic bacterium such as E.coli, coagulase positive S.aureus, catalase negative group D. Steptococci, Salmonella, Vibrio cholerae, V.parahemolytica and L.monocytogenes were found among these dried fish samples. The fungal counts were noticed in all the dried fish samples with ranged between 4.0 x 101 to9.6 x 103 cfu.g-1 in Dichloran Rose Bengal Chloramphenicol Agar (DRBC Agar) and the fungal species were belong to the Aspergillus, Penecillium, Mucor and Rhizobus species. Majority of the fungal species are mainly of Aspergillus species. The Gold spotted anchovy and Bombay duck dry fish samples also contains the total yeast counts of less than 10 cfu.g-1. The present investigation revealed that the overall microbial acceptable quality of dry fish samples prepared under traditional sun drying method was good and the quality should be maintained further by proper packaging and storing of the dry fish samples until reach the consumers.Not Availabl

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Not AvailableSmart packaging, the combination of active and intelligent packaging, which on the one hand monitors changes in the product and on the other hand acts upon these changes, is a promising concept. In the present study, a smart packaging system combining freshness indicators and antimicrobial film was used for monitoring and managing spoilage of barracuda fish steaks stored at 2 degree celsius. Antimicrobial film was prepared from shrimp shell derived chitosan added with ginger essential oil. GEO incorporation improved antimicrobial activity, antioxidant capacity, water barrier property and thermal stability of CH films. GEO at lower concentrations didn’t significantly affect the mechanical properties of CH film. FTIR spectra indicated that functional groups of phenolic compounds were more recognizable with increasing GEO concentration in CH film. As observed from scanning electron microscopy of the film, presence of GEO resulted in a heterogenous structure in CH film. Volatile base formation and microbial growth in barracuda steaks packed with CH-GEO film were significantly lower than control. pH sensitive dyes were used as freshness indicators to monitor the quality of chill stored barracuda steaks. Among the various dyes used, bromocresol purple was the most effective visual indicator of barracuda deterioration. The results of the present study indicate that CH-GEO film is an effective packaging material with potential bioactivities for improving the keeping quality of fish steaks and synergistic use of freshness indicator and antimicrobial film can provide the consumers a more safe fish.Not Availabl

Pre-treatment optimisation of SWRO membrane desalination under tropical conditions

10.5004/dwt.2009.459Desalination and Water Treatment31-3183-19