183 research outputs found
Modelling of the radio spectrum evolution in the binary pulsar B125963
In this paper we give the first attempt to model the evolution of the
spectrum of PSR B125963 radio emission while the pulsar orbits the companion
Be star. As suggested by Kijak et al. (Mon. Not. R. Astron. Soc. 418:L114,
2011a) this binary system can be useful in understanding the origin of the
gigahertz-peaked spectrum of pulsars. The model explains, at least
qualitatively, the observed alterations of the spectral shape depending on the
orbital phases of this pulsar. Thus, our results support the hypothesis that
the external factors have a significant impact on the observed radio emission
of a pulsar. The model can also contribute to our understanding of the origin
of some non-typical spectral shapes(e.g. flat or broken spectra).Comment: 9 pages, 2 tables, 3 figure
Growth Kinetics of Vitamin C Crystals in a Batch L(+)-Ascorbic Acid â Methanol â Ethanol â Water System: Size Independent Growth Model Approach
The experimental data concerning growth kinetics of vitamin C (L(+)-ascorbic acid, LAA) crystals in a seeded and cooling batch mass crystallization process realized in a fourâcompound: L(+)-ascorbic acidâmethanolâethanolâwater system are reported. Influences of initial composition of solution and its linear cooling rate on âaverage, effectiveâ values of crystal linear growth rate were examined. Small divergences between LAA crystal size distributions (CSDs) data from granulometric analysis and Coulter counter were interpreted theoretically and discussed. Linear growth rates of crystals in a batch crystallizer were acquired with a proposed by NĂ˝vlt indirect method, based on the analysis of population density n(L) data in a MSMPR (mixed suspension mixed product removal) crystallizer. Sizeâindependent growth (SIG) kinetics was assumed. It can be concluded, that the largest and the most uniform particles of purified, crystalline vitamin C correspond to higher initial concentration of L(+)-ascorbic acid in a solution and lower cooling rate applied
Growth Kinetics of Vitamin C Crystals in a Batch L(+)-Ascorbic Acid â Methanol â Ethanol â Water System: Size Independent Growth Model Approach
The experimental data concerning growth kinetics of vitamin C (L(+)-ascorbic acid, LAA) crystals in a seeded and cooling batch mass crystallization process realized in a fourâcompound: L(+)-ascorbic acidâmethanolâethanolâwater system are reported. Influences of initial composition of solution and its linear cooling rate on âaverage, effectiveâ values of crystal linear growth rate were examined. Small divergences between LAA crystal size distributions (CSDs) data from granulometric analysis and Coulter counter were interpreted theoretically and discussed. Linear growth rates of crystals in a batch crystallizer were acquired with a proposed by NĂ˝vlt indirect method, based on the analysis of population density n(L) data in a MSMPR (mixed suspension mixed product removal) crystallizer. Sizeâindependent growth (SIG) kinetics was assumed. It can be concluded, that the largest and the most uniform particles of purified, crystalline vitamin C correspond to higher initial concentration of L(+)-ascorbic acid in a solution and lower cooling rate applied
Population genetics of 30 INDELs in populations of Poland and Taiwan
The Investigator DIPplex(ÂŽ) kit (Qiagen) contain components for the simultaneous amplification and analysis of 30 biallelic autosomal INDELs and amelogenin. The objective of this study was to estimate the diversity of the 30 markers in Polish (N(P)Â =Â 122) and Taiwanese (N(T)Â =Â 126) population samples and to evaluate their usefulness in forensic genetics. All amplicon lengths were shorter than 160 base pairs. The DIPplex genotype distributions showed no significant deviation from HardyâWeinberg rule expectations (Bonferroni corrected) except for DLH39 in the Taiwanese population. Among the Poles and the Taiwanese the mean observed heterozygosity values are 0.4385 and 0.4079, and the combined matching probability values are 7.98Â ĂÂ 10(â14) and 1.22Â ĂÂ 10(â11), respectively. The investigated marker set has been confirmed as a potential extension to standard short tandem repeat-based kits or a separate informative system for individual identification and kinship analysis. Eight INDELs have been selected as possible ancestry informative single-nucleotide polymorphisms for further analyses
Continuous reactive crystallization of pharmaceuticals using impinging jet mixers
For reactive crystallization of pharmaceuticals that show a rapid reaction rate, low solubility of active pharmaceutical ingredient and hence a large supersaturation, it was found in a recent study that a process design which integrates an impinging jet mixer and batch stirred tank produces high quality crystals. The current investigation examines if the short processing time of reactive crystallization permits the impinging jet mixerâstirred tank design to be modified to operate in a continuous mode. The new design combines an impinging jet mixer for feed introduction and reaction with a continuous stirred tank reactor (CSTR) and tubular reactor for crystal growth. A study of reactive crystallization of sodium cefuroxime (an antibiotic), using first a 1L CSTR then scaling to a 50L CSTR, found that the new design produces crystals of higher crystallinity, narrower particle size, and improved product stability, than batch crystallizers
Cucurbiturils as supramolecular inhibitors of DNA restriction by type II endonucleases
Cucurbiturils (CB6 and CB7) were shown to inhibit the enzymatically catalyzed restriction of plasmids and linear DNA. This effect can be inverted by supramolecular masking of the macrocycles through competitive complexation with polyamines. These experiments provide supramolecular control of biocatalytic processes.Spanish MINECO [CTQ2011-28390]; FEDER; COST [CM1005]; DFG [NA-686/5]; Portuguese FCT [SFRH/BD/81628/2011, PEst-OE/EQB/LA0023/2013
Enhanced MFC power production and struvite recovery by the addition of sea salts to urine
Š 2016 The Authors Urine is an excellent fuel for electricity generation in Microbial Fuel Cells (MFCs), especially with practical implementations in mind. Moreover, urine has a high content in nutrients which can be easily recovered. Struvite (MgNH4PO4¡6H2O) crystals naturally precipitate in urine, but this reaction can be enhanced by the introduction of additional magnesium. In this work, the effect of magnesium additives on the power output of the MFCs and on the catholyte generation is evaluated. Several magnesium sources including MgCl2, artificial sea water and a commercially available sea salts mixture for seawater preparation (SeaMix) were mixed with real fresh human urine in order to enhance struvite precipitation. The supernatant of each mixture was tested as a feedstock for the MFCs and it was evaluated in terms of power output and catholyte generation. The commercial SeaMix showed the best performance in terms of struvite precipitation, increasing the amount of struvite in the solid collected from 21% to 94%. Moreover, the SeaMix increased the maximum power performance of the MFCs by over 10% and it also changed the properties of the catholyte collected by increasing the pH, conductivity and the concentration of chloride ions. These results demonstrate that the addition of sea-salts to real urine is beneficial for both struvite recovery and electricity generation in MFCs
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