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CO2 as a solvent for natural pesticides
Get PDFU ovom su radu procijenjene topljivosti prirodnih pesticida – složenih organskih spojeva
(triterpenoidi azadirahtin, nimbin i salanin dobiveni iz nima te piretrini piretrin I i II, cinerin I
i II i jasmolin I i II dobiveni iz cvjetova različitih vrsti krizantema) – u smjesama nadkritičnog
CO2 i etanola. Potrebni parametri za procjenu topljivosti dobiveni su raspoloživim
empirijskim metodama, odnosno Peng-Robinsonovom jednadžbom stanja. Ravnotežni tlakovi
sublimacije procijenjeni različitim metodama međusobno nisu slagali i za po nekoliko redova
veličine, što je uvelike ograničavalo pouzdanost procjena topljivosti. Proračun topljivosti
stoga je ograničen samo na nimbin – rezultati su pokazali da se najveća topljivost može
očekivati pri nižim temperaturama i srednjim tlakovima, te da povećanje udjela etanola u
smjesi s nadkritičnim CO2 povećava njegovu topljivost.In this paper the solubilities of natural pesticides – complex organic compounds (triterpenoids
azadirachtin, nimbin and salanin derived from neem seeds and pyrethrins pyrethrin I and II,
cinnerin I and II and jasmolin I and II obtained from the flowers of various chrysanthemum
species) – in the mixtures of supercritical CO2 and ethanol were estimated. The required
parameters for assessing the solubility were obtained by available empirical methods as well
as with the Peng-Robinson equation of state. The sublimation pressures of pure solids
estimated with different methods were not coherent and differed by several orders of
magnitude, which greatly limited the reliability of obtained estimates. Therefore only the
solubility of nimbin was calculated – the results showed that the largest solubility may be
expected at lower temperatures and medium pressures; the increase of ethanol content in the
mixture with CO2 was found to increase the solubility
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Copolymerization reactivity of 2-(tert-butylamino)ethyl methacrylate
No full textU ovom radu se istraživala kopolimerizacijska reaktivnost 2-(tert-butilamino) etil metakrilata (TBAEMA) u procesima radikalske kopolimerizacije do niskih masenih konverzija (<10 %) s metil-metakrilatom (MMA), stirenom (ST) i oktadecil-metakrilatom (ODMA). Svaki sustav kopolimeriziran je u različitim sastavima, odnosno različitih molnih udjela monomera (90/10, 80/20, 70/30, 60/40, 50/50, 40/60, 30/70, 20/80 i 10/90). Dobiveni kopolimeri karakterizirani su različitim metodama te im je određen sastav pomoću 1H nuklearne magnetske rezonancijske spektroskopije, zatim su određeni fazni prijelazi diferencijalnom skenirajućom kalorimetrijom, toplinska stabilnost termogravimetrijom te raspodjela molekulskih masa kromatografijom na propusnom gelu. Omjeri kopolimerizacijskih reaktivnosti monomera izračunati su različitim linearnim (Finneman-Ross, invertirana Finneman-Ross, Kelen-Tüdős i proširena Kelen-Tüdős) metodama i nelineranom Tidwell-Mortimerovom metodom. Dobivene vrijednosti za r1 i r2 za MMA-TBAEMA sustav su približno jednaki jedinici, što ukazuje na idealnu kopolimerizaciju dok su kod ostalih uočena malo veća odstupanja – ST-TBAEMA ima vrijednosti uglavnom manje od jedan, dok ODMA-TBAEMA veće od jedan te upućuju na neidealnu azeotropnu kopolimerizaciju. Uočeno je negativno djelovanje TBAEMA na toplinsku stabilnost kopolimera, kao i snižavanje staklišta s obzirom da homopolimer ima razmjerno nisku temperaturu staklastog prijelaza u odnosu na ostale homopolimere. Kromatografija na propusnom gelu za određivanje raspodjele molekulskih masa neuspješna je u smislu nedostatka dobrog signala od TBAEMA.This paper studies the copolymerization reactivity of 2-(tert-butylamino)ethyl methacrylate (TBAEMA) through the low mass conversion (<10%) radical copolymerization with methyl methacrylate (MMA), styrene (ST) and octadecyl methacrylate (ODMA). Each system is copolymerized in different compositions, i.e. with different molar ratios of monomers (90/10, 80/20, 70/30, 60/40, 50/50, 40/60, 30/70, 20/80 and 10/90). The resulting copolymers were characterized by different methods: the composition was determined by 1H nuclear magnetic resonance spectroscopy, the phase transitions with differential scanning calorimetry, thermal stability by thermogravimetry and distribution of molecular mass by gel permeation chromatography. The copolymerization reactivity coefficients of monomers were calculated with different linear (Finneman-Ross, inverted Finneman-Ross, Kelen-Tüdős and extended Kelen-Tüdős) methods and non-linear Tidwell-Mortimer method. The obtained values for r1 and r2 for the MMA-TBAEMA system are approximately equal to 1, indicating ideal copolymerisation while others have slight deviations – ST-TBAEMA has values mostly less than 1, while ODMA-TBAEMA has mostly values above 1 and that indicates to non-ideal azeotropic copolymerization. A negative effect of TBAEMA on the thermal stability of other monomers was noted as well as lowering of the glass transition temperature as TBAEMA has a relatively low glass transition temperature relative to the other monomers. Gel permeation chromatography for the analysis of molecular mass distribution was unsuccessful in the sense of the absence of a good signal from TBAEMA
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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