Proizvodnja amorfnih traka gotovo stalnog stupnja amorfnosti

This paper describes a modified melt spinning method that provides for production of amorphous ribbons with a nearly constant short-range order. The ribbon structure can be controlled by relevant parameters, and if these parameters are constant, the ribbons produced have approximately the same degree of amorphousness. A detailed investigation proved that it was necessary to control accurately the melting temperature and the surface velocity of the drum on which the quenching is made. The system is computer controlled using specially adapted software. The particular phases during the process of amorphous ribbon production are turned on in accordance with the temperature of the melt. We made a comparative measurement of produced ribbons proving that ribbons produced with the same parameters have approximately the same degree of amorphousness.Opisujemo usavršenu metodu taljevine na rotirajućem valjku kojom se proizvode amorfne trake gotovo stalnog kratko-dosežnog uređenja. Struktura traka može se upravljati putem parametara, a ako su ti parametri stalni, proizvedene trake imaju jednake stupnjeve amorfnosti. Pažljiva ispitivanja su pokazala da je potrebno točno podesiti temperaturu taljevine i obodnu brzinu hlađenog valjka kojim se postiže brzo hlađenje. Uređajem upravlja računalo koje rabi posebno preuređen program. Pojedine faze proizvodnje se uključuju ovisno o temperaturi taljevine. Načinili smo usporedbena mjerenja s proizvedenim trakama uz jednake parametre koja pokazuju da postižemo stalne stupnjeve amorfnosti

Proizvodnja amorfnih traka gotovo stalnog stupnja amorfnosti

This paper describes a modified melt spinning method that provides for production of amorphous ribbons with a nearly constant short-range order. The ribbon structure can be controlled by relevant parameters, and if these parameters are constant, the ribbons produced have approximately the same degree of amorphousness. A detailed investigation proved that it was necessary to control accurately the melting temperature and the surface velocity of the drum on which the quenching is made. The system is computer controlled using specially adapted software. The particular phases during the process of amorphous ribbon production are turned on in accordance with the temperature of the melt. We made a comparative measurement of produced ribbons proving that ribbons produced with the same parameters have approximately the same degree of amorphousness.Opisujemo usavršenu metodu taljevine na rotirajućem valjku kojom se proizvode amorfne trake gotovo stalnog kratko-dosežnog uređenja. Struktura traka može se upravljati putem parametara, a ako su ti parametri stalni, proizvedene trake imaju jednake stupnjeve amorfnosti. Pažljiva ispitivanja su pokazala da je potrebno točno podesiti temperaturu taljevine i obodnu brzinu hlađenog valjka kojim se postiže brzo hlađenje. Uređajem upravlja računalo koje rabi posebno preuređen program. Pojedine faze proizvodnje se uključuju ovisno o temperaturi taljevine. Načinili smo usporedbena mjerenja s proizvedenim trakama uz jednake parametre koja pokazuju da postižemo stalne stupnjeve amorfnosti

THE APPLICATION OF DP POLAROGRAPHY FOR THE DETERMINATION OF ZINC AND CONTENT OF ZINC PYRITHIONE IN ANTI-DANDRUFF SHAMPOOS

Commercially formulated anti-dandruff shampoos contain zinc pyrithione (ZPT) as an active ingredient that has antifungal, antibacterial and anti-seborrheic properties. The determination of ZPT concentration in commercial anti-dandruff shampoos by differential pulse polarography (DPP) was based on the electrochemical reduction of zinc ions in ammoniacal buffer pH 10.2, and the linear dependence of the reduction differential pulse peak current at the potential - 1.33 V vs. concentration of zinc. Using the calibration curve method, it was found that the range of linearity for the determination of zinc concentration was from 1.28 ´ 10‒5 to 1.39 ´ 10-4 mol L‒1 (linear regression equation: I = - 0.097 + 6.635 ´ 105c). Surface active ingredients and micro-components in the shampoos did not exert a polarographic interference for the determination of zinc and did not affect the indirect determination of the content of the active ingredient ZPT. The concentrations of zinc in the analyzed anti-dandruff shampoo samples were determined by the standard addition method, resulting in 4.20 ´ 10‒2 mol L‒1, 1.76 ´ 10‒1 mol L‒1 and 1.82 ´ 10‒1 mol L‒1. The results of DPP determinations of zinc and ZPT show that the content of ZPT was 0.28%, 1.15% i.e. 1.19% and was below the maximum recommended level of ZPT in anti-dandruff shampoos. This simple and sensitive differential pulse polarography method is suitable for a routine and rapid control of the active ingredient content, as well as for the quality control of anti-dandruff shampoos. PRIMENA DP POLAROGRAFIJE ZA ODREĐIVANJE CINKA I SADRŽAJA CINK-PIRITIONA U ŠAMPONIMA PROTIV PERUTIAktivni sastojak komercijalno formulisanih šampona protiv peruti je cink-pirition, koji ima antifungalno, antibakterijsko i antiseboreično dejstvo. Određivanje cink-piritiona u šamponima protiv peruti primenom metode diferencijalne pulsne polarografije zasnivalo se na elektrohemijskoj redukciji jona cinka u amonijačnom puferu pH 10,2 i linearnoj zavisnosti intenziteta struje pika na redukcionom potencijalu - 1,33 V i koncentracije cinka. Metodom kalibracione krive je određen opseg linearnosti za određivanje koncentracije cinka od 1,28 ´ 10‒5 do 1,39 ´ 10‒4 mol L-1 i dobijena je linearna regresiona jednačina I = - 0,097 + 6,635´105c. Utvrđeno je da površinski aktivne komponente u matriksu šampona ne pokazuju polarografsku interferenciju i ne utiču na određivanje koncentracije cinka i sadržaja cink-piritiona u analiziranim šamponima. Koncentracije cinka u analiziranim uzorcima šampona određene su metodom standardnog dodatka i iznose 4,20 ´ 10‒2 mol L-1, 1,76 ´ 10‒1 mol L-1 i 1,82 ´ 10‒1 mol L-1. Rezultati polarografskog određivanja cinka i sadržaja cink-piritiona pokazuju da su dobijene vrednosti cink-piritiona 0,28%, 1,15% i 1,19% ispod maksimalno preporučenog sadržaja cink-piritiona u šamponima protiv peruti. Ova jednostavna i osetljiva metoda diferencijalno pulsne polarografije pogodna je za rutinsko i brzo određivanje sadržaja aktivnog sastojka i kontrolu kvaliteta šampona protiv peruti. HIGHLIGHTSCommercially formulated anti-dandruff shampoos contain zinc pyrithione (ZPT) as an active ingredient that has antifungal, antibacterial and anti-seborrheic effects;ZPT is based on the organic entity pyrithione (PT) in which a zinc ion forms a metal complex with PT in a 1 : 2 ratio;Determination of ZPT concentration in commercial anti-dandruff shampoos by differential pulse polarography is based on electrochemical reduction of zinc ions in ammoniacal buffer of pH 10.2;Surface active ingredients (anionic and amphoteric) and micro-components in the shampoos do not show a polarographic interference for determination of zinc and do not affect determination of the content of ZPT active ingredient;A simple and sensitive differential pulse polarography method is suitable for routine and rapid control of the active ingredient content, as well as for quality control of anti-dandruff shampoos

Primena DP polarografije za određivanje cinka i sadržaja cink-piritiona u šamponima protiv peruti

Commercially formulated anti-dandruff shampoos contain zinc pyrithione (ZPT) as an active ingredient that has antifungal, antibacterial and anti-seborrheic properties. The determination of ZPT concentration in commercial anti-dandruff shampoos by differential pulse polarography (DPP) was based on the electrochemical reduction of zinc ions in ammoniacal buffer pH 10.2, and the linear dependence of the reduction differential pulse peak current at the potential - 1.33 V vs. concentration of zinc. Using the calibration curve method, it was found that the range of linearity for the determination of zinc concentration was from 1.28 x 10-5 to 1.39 x 10-4 mol L‒1 (linear regression equation: I = - 0.097 + 6.635 x 105c). Surface active ingredients and micro-components in the shampoos did not exert a polarographic interference for the determination of zinc and did not affect the indirect determination of the content of the active ingredient ZPT. The concentrations of zinc in the analyzed anti-dandruff shampoo samples were determined by the standard addition method, resulting in 4.20 x 10‒2 mol L‒1, 1.76 x 10‒1 mol L‒1 and 1.82 x 10‒1 mol L‒1. The results of DPP determinations of zinc and ZPT show that the content of ZPT was 0.28%, 1.15% i.e. 1.19% and was below the maximum recommended level of ZPT in anti-dandruff shampoos. This simple and sensitive differential pulse polarography method is suitable for a routine and rapid control of the active ingredient content, as well as for the quality control of anti-dandruff shampoos.Aktivni sastojak komercijalno formulisanih šampona protiv peruti je cink-pirition, koji ima antifungalno, antibakterijsko i antiseboreično dejstvo. Određivanje cink-piritiona u šamponima protiv peruti primenom metode diferencijalne pulsne polarografije zasnivalo se na elektrohemijskoj redukciji jona cinka u amonijačnom puferu pH 10,2 i linearnoj zavisnosti intenziteta struje pika na redukcionom potencijalu - 1,33 V i koncentracije cinka. Metodom kalibracione krive je određen opseg linearnosti za određivanje koncentracije cinka od 1,28 x 10‒5 do 1,39 x 10‒4 mol L-1 i dobijena je linearna regresiona jednačina I = - 0,097 + 6,635 x 105c. Utvrđeno je da površinski aktivne komponente u matriksu šampona ne pokazuju polarografsku interferenciju i ne utiču na određivanje koncentracije cinka i sadržaja cink-piritiona u analiziranim šamponima. Koncentracije cinka u analiziranim uzorcima šampona određene su metodom standardnog dodatka i iznose 4,20 x 10‒2 mol L-1, 1,76 ' 10‒1 mol L-1 i 1,82 x 10‒1 mol L-1. Rezultati polarografskog određivanja cinka i sadržaja cink-piritiona pokazuju da su dobijene vrednosti cink-piritiona 0,28%, 1,15% i 1,19% ispod maksimalno preporučenog sadržaja cink-piritiona u šamponima protiv peruti. Ova jednostavna i osetljiva metoda diferencijalno pulsne polarografije pogodna je za rutinsko i brzo određivanje sadržaja aktivnog sastojka i kontrolu kvaliteta šampona protiv peruti

A Vinča potscape: formal chronological models for the use and development of Vinča ceramics in south-east Europe.

Recent work at Vinča-Belo Brdo has combined a total of more than 200 radiocarbon dates with an array of other information to construct much more precise narratives for the structural history of the site and the cultural materials recovered from it. In this paper, we present the results of a recent attempt to construct formal models for the chronology of the wider Vinča potscape, so that we can place our now detailed understanding of changes at Belo Brdo within their contemporary contexts. We present our methodology for assessing the potential of the existing corpus of more than 600 radiocarbon dates for refining the chronology of the five phases of Vinča ceramics proposed by Milojčić across their spatial ranges, including a total of 490 of them in a series of Bayesian chronological models. Then we outline our main results for the development of Vinča pottery. Finally, we discuss some of the major implications for our understanding of the source, character and tempo of material change

Enclosing the Neolithic World: A Vinča Culture Enclosed and Fortified Settlement in the Balkans

Interpretations of prehistoric enclosures worldwide have varied from those that see the primary role of enclosures as defensive features to others that explore the symbolic, ritual, social, and ideological dimensions of separating space into an inside, an outside, and an in-between. Such evidence and interpretative accounts are inevitably linked to wider anthropological discussions on modes of social interaction and reproduction in the past, whether altruistic or predatory, and evolutionary narratives regarding changes in the level of intergroup violence over the course of human history. Growing evidence indicates that many Neolithic settlements in Europe were enclosed by a complex system of ditches, ramparts, and palisades. We present a case study from the central Balkans at the Neolithic Vinča culture site of Oreškovica-Selište in Serbia, dated to the last centuries of the sixth millennium BC, where recent geophysical surveys, stratigraphic excavation, and accelerator mass spectrometry dating document the existence of an early enclosed settlement with multiple enclosure features. We interpret these features as defensive and discuss the social dynamics that led to the founding and abandonment of this short-lived occupation in the context of other contemporaneous settlements in the Balkans

Doppler radar remote sensing of respiratory function

Doppler radar remote sensing of torso kinematics can provide an indirect measure of cardiopulmonary function. Motion at the human body surface due to heart and lung activity has been successfully used to characterize such measures as respiratory rate and depth, obstructive sleep apnea, and even the identity of an individual subject. For a sedentary subject, Doppler radar can track the periodic motion of the portion of the body moving as a result of the respiratory cycle as distinct from other extraneous motions that may occur, to provide a spatial temporal displacement pattern that can be combined with a mathematical model to indirectly assess quantities such as tidal volume, and paradoxical breathing. Furthermore, it has been demonstrated that even healthy respiratory function results in distinct motion patterns between individuals that vary as a function of relative time and depth measures over the body surface during the inhalation/exhalation cycle. Potentially, the biomechanics that results in different measurements between individuals can be further exploited to recognize pathology related to lung ventilation heterogeneity and other respiratory diagnostics