1,720,956 research outputs found
Potentionetric determination of biologically active compounds with carbon paste electrodes - review : bachelor thesis
No full textIonsko-selektivne elektrode pokazuju selektivan odziv na određenu vrstu iona u otopini. Elektrode na bazi ugljikove paste (CPE) su jedan od primjera tih elektroda. Mnogi znanstveni radovi opisuju razne CPE te rezultate njihovih mjerenja. U ovom radu dat je pregled CPE, njihove priprave, osnovnih karakteristika te praktične primjene. Potenciometrija s CPE se pokazala jednako dobra ili bolja od konvencionalnih metoda mjerenja- jeftinija je, jednostavnija, brža i nižeg praga detekcije. U praksi se koristi u kulometriji, voltmetriji, amperometriji i potenciometriji u farmaceutskim ispitivanjima, za mjerenje štetnih metala u uzorcima vode, kao biosenzor glukoze, za mjerenje tumorskih markera i kolesterola u krvi, detekciju mikroorganizama...Ion-selective electrodes show a selective response to a particular type of ion in solution. Carbon paste electrodes (CPE) are an example of these electrodes. Many scientific papers describe various CPEs and the results of their measurements. This paper provides an overview of CPEs, their preparation, basic characteristics and practical application. Potentiometry with CPE has proven to be just as good or better than conventional measurement methods - it is cheaper, simpler, faster and has a lower detection threshold. In practice, it is used in coulometry, voltmetry, amperometry and potentiometry in pharmaceutical tests, measuring harmful metals in water samples, as a glucose biosensor, for measuring tumor markers and cholesterol in the blood, detection of microorganisms..
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
Testing of the membrane response based on Ag2S:AgCl:PTFE=1:1:2 with the addition of magnetite nanoparticles : diploma thesis
No full textPotenciometrijska metoda se pokazala najučinkovitijom zbog jednostavnosti, praktičnosti te niske cijene, i upravo zbog toga je korištena u ovom radu. Korištene ion-selektivne elektrode pripremljene su od srebrovog sulfida, srebrovog klorida te politetrafluoretilen u omjeru 1:1:2 uz dodatak različitih omjera nanočestica magnetita. Metodom slijednog razrjeđivanja ispitan je odziv na srebrove ione u otopini srebrovog nitrata te odziv na kloridne ione u otopini natrijevog klorida. Selektivnost same metode je ispitana promjenom reakcijskih uvjeta kao što je pH otopine uzorka, te su se ispitivanja vršila pri tri različita pH=0, 1 i 2. Potenciometrijska mjerenja se vrše dok se ne postigne razlika potencijala manja od 1 mV između posljednja dva razrijeđena. Testiranje svake membrane se vrši tri puta a rezultati mjerenja su prikazani grafički.The potentiometric method proved to be the most effective due to its simplicity, practicality and low cost, and that is the reason why it is used in this work. The used ion-selective electrodes were prepared from silver sulfide, silver chloride and polytetrafluoroethylene in a ratio of 1:1:2 with the addition of different percentages of magnetite nanoparticles. The response to silver ions was tested in a silver nitrate solution and the response to chloride ions in a sodium chloride solution using a serial dilution method. The selectivity of this method was tested by changing the reaction conditions such as the pH of the sample solution, and the tests were performed at three different pH=0, 1 and 2. Potentiometric measurements are performed until a potential difference between last two dilutions is less than 1 mV. Each membrane is tested three times, and the measurement results are presented graphically
Testing of the membrane response based on Ag2S:AgCl:PTFE=1:1:2 with the addition of magnetite nanoparticles : diploma thesis
No full textPotenciometrijska metoda se pokazala najučinkovitijom zbog jednostavnosti, praktičnosti te niske cijene, i upravo zbog toga je korištena u ovom radu. Korištene ion-selektivne elektrode pripremljene su od srebrovog sulfida, srebrovog klorida te politetrafluoretilen u omjeru 1:1:2 uz dodatak različitih omjera nanočestica magnetita. Metodom slijednog razrjeđivanja ispitan je odziv na srebrove ione u otopini srebrovog nitrata te odziv na kloridne ione u otopini natrijevog klorida. Selektivnost same metode je ispitana promjenom reakcijskih uvjeta kao što je pH otopine uzorka, te su se ispitivanja vršila pri tri različita pH=0, 1 i 2. Potenciometrijska mjerenja se vrše dok se ne postigne razlika potencijala manja od 1 mV između posljednja dva razrijeđena. Testiranje svake membrane se vrši tri puta a rezultati mjerenja su prikazani grafički.The potentiometric method proved to be the most effective due to its simplicity, practicality and low cost, and that is the reason why it is used in this work. The used ion-selective electrodes were prepared from silver sulfide, silver chloride and polytetrafluoroethylene in a ratio of 1:1:2 with the addition of different percentages of magnetite nanoparticles. The response to silver ions was tested in a silver nitrate solution and the response to chloride ions in a sodium chloride solution using a serial dilution method. The selectivity of this method was tested by changing the reaction conditions such as the pH of the sample solution, and the tests were performed at three different pH=0, 1 and 2. Potentiometric measurements are performed until a potential difference between last two dilutions is less than 1 mV. Each membrane is tested three times, and the measurement results are presented graphically
Testing of the membrane response based on Ag2S:AgCl:PTFE=1:1:2 with the addition of magnetite nanoparticles : diploma thesis
No full textPotenciometrijska metoda se pokazala najučinkovitijom zbog jednostavnosti, praktičnosti te niske cijene, i upravo zbog toga je korištena u ovom radu. Korištene ion-selektivne elektrode pripremljene su od srebrovog sulfida, srebrovog klorida te politetrafluoretilen u omjeru 1:1:2 uz dodatak različitih omjera nanočestica magnetita. Metodom slijednog razrjeđivanja ispitan je odziv na srebrove ione u otopini srebrovog nitrata te odziv na kloridne ione u otopini natrijevog klorida. Selektivnost same metode je ispitana promjenom reakcijskih uvjeta kao što je pH otopine uzorka, te su se ispitivanja vršila pri tri različita pH=0, 1 i 2. Potenciometrijska mjerenja se vrše dok se ne postigne razlika potencijala manja od 1 mV između posljednja dva razrijeđena. Testiranje svake membrane se vrši tri puta a rezultati mjerenja su prikazani grafički.The potentiometric method proved to be the most effective due to its simplicity, practicality and low cost, and that is the reason why it is used in this work. The used ion-selective electrodes were prepared from silver sulfide, silver chloride and polytetrafluoroethylene in a ratio of 1:1:2 with the addition of different percentages of magnetite nanoparticles. The response to silver ions was tested in a silver nitrate solution and the response to chloride ions in a sodium chloride solution using a serial dilution method. The selectivity of this method was tested by changing the reaction conditions such as the pH of the sample solution, and the tests were performed at three different pH=0, 1 and 2. Potentiometric measurements are performed until a potential difference between last two dilutions is less than 1 mV. Each membrane is tested three times, and the measurement results are presented graphically
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
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