Wyniki wyszukiwania - Biblioteka Nauki

1

Microhardness as a method for investigation of fossil resins

100%

Czapla D. , Natkaniec-Nowak L. , Drzewicz P.

Geology, Geophysics and Environment

|

2016

|

tom Vol. 42, no. 1

63--64

EN

Natural fossil resins are products of deciduous and coniferous trees formed at least 40 million years ago. The fact that fossil resins survived until the present day is due to appropriate processes and conditions. One of them is the ability to polymerize. There are types of chemical structures derived from the original plant secretions which formed polymerized or macromolecular connection resistant to various environmental factors (Penney 2010). The polymerization process gives property of better susceptibility to mechanical machining, and thus jeweler’s usefulness (Matuszewska 2015). Fossil resins are being found along the southern coast of the Baltic Sea (from Jutland Peninsula to the Sambia) and ranges stretching trough Germany, Poland, Lithuania, Latvia, Belarus and Ukraine (Czechowski et al. 1996, Heflik & Natkaniec-Nowak 2011). They are also occurring in other locations, for example in Mexico, Domini - can Republic, Colombia and SE Asia (e.g. Myanmar, Indonesia). The most commonly used diagnostic methods for fossil resins are spectroscopic methods (FT-IR, RS) (Kosmowska-Ceranowicz 1999a). They allow identification of different varieties of resins and get to know their internal structure (Czechowski et al. 1996, Kosmowska-Ceranowicz 1999b, Matuszewska 2010, 2015). Quantification possibilities have also other methods, such as X-ray fluorescence, diffractometry, and most of allchemical methods. In recent years, t method for determining the absolute hardness (microhardness) (Matuszewska & Gołąb 2008) was added to these analytical techniques. This parameter clearly shows the relationship between physico-chemical features with different aspects of their genesis. It can be helpful in determining the age of resins (Matuszewska et al. 2002). Hardness as the primary diagnostic feature of many minerals is evaluated relatively to model of 10 minerals in Mohs scale. Reported in the literature (Savkievich 1967, Popkova 1984, Matuszewska 2009), hardnesses of fossil resins are from 1 to 3, which correspond to hardness of talc (1), gypsum (2) and calcite (3). It therefore varies; for succinite (which is treated as a model for fossil resins) range is from 1.5 to 3, while Colombian copal from 1 to 1.5. It depends mainly on the degree of macromolecular structure condensation of these materials. The subjects of the study were samples of fossil resins selected from Mexico (Chiapas), Dominican Republic (Barahona) and Colombia (Velez). In addition, for comparison purposes Baltic succinite were measured. The measurements were done in Gemological Laboratory at WGGiOŚ AGH using a microhardness tester PMT-3 from Russian manufacturer. For the determination of this parameter Vickers method was used, according to which the microhardness determines the ratio of the pressure force of diamond pyramid with load to the lateral surface of the depth print. For measurement, 250 mg load. The test was conducted on the smooth surface of each of 6 samples repeating the measurement 20 times. The obtained results allow concluding clearly that the individual fossil resin samples are significantly different from each other. These differences result from different places of origin and age, thus the conditions of the geological, natural environment, climate, etc. Average value of the microhardness for fossil resins from Mexico and Colombia is the lowest – respectively 18.54 kG/mm 2 and 19.87 kG/mm 2 . In turn, the value of this parameter for the samples from Dominican Republic is significantly higher (yellow resin – 26.59 kG/mm 2 ; orange resin – 27.76 kG/mm 2 ; dark red resin – 26.57 kG/mm 2 ). Succinite achieves the highest values of microhardness in comparison with other resins. This is due to the difference in their ages – Eocene Baltic amber, is the oldest studied resin, therefore condensation processes in the structure are more advanced. Slightly lower values achieve Miocene – Oligocene resins from Dominican Republic. Lower Miocene – upper Oligocene and Pleistocene – Pliocene samples from Mexico and Colombia, have the lowest microhardness. The differences in microhardness of various resins may be explained by the fact that their fossilization underwent in different environmental conditions. The environmental conditions were different in various geographical locations. The degree of condensation and polymerization of the resins and their hardness increased with time. Therefore, in case of the oldest investigated resin, succinite-Baltic amber, the measured microhardeness was the highest.

2

Zastosowanie promieniowania jonizującego do degradacji wybranych pestycydów w wodach i ściekach

88%

Bojanowska-Czajka A. , Drzewicz P. , Nałęcz-Jawecki G. , Sawicki J. , Trojanowicz M.

Postępy Techniki Jądrowej

|

2006

|

tom z. 1

26-31

3

Zastosowanie promieniowania jonizującego do degradacji zanieczyszczeń organicznych w wodach i ściekach

88%

Drzewicz P. , Bojanowska-Czajka A. , Nałęcz-Jawecki G. , Sawicki J. , Trojanowicz M.

Postępy Techniki Jądrowej

|

2002

|

tom Vol. 45, z. 1

27-32

4

Chromatographic determination of the products of gamma radiolysis of aqueous solutions of chlorophenoxy acid herbicides

88%

Biesaga M. , Stafiej A. , Pyrzyńska K. , Drzewicz P. , Trojanowicz M.

Chemia Analityczna

|

2005

|

tom Vol. 50, No. 5

863-873

EN

In this study a reversed-phase HPLC procedure for the simultaneous determination of chlorophenoxy acid herbicides and their radiolytic degradation products has been elaborated. Satisfactory separation has been achieved with a mobile phase consisting of 60% 26 mmol L-1 acetic acid (pH 2.5} and 40% (v/v) acetonitrile. LOD values for herbicides andphenol derivatives were in the ranges of 19-41 μ L-1 and 10-60 μ L-1 respectively, applying spectrophotometric detection at 280 nm. The developed method has been applied for the monitoring of the efficiency of gamma radiolysis of commonly used herbicides:MCPA and dicamba.

PL

Wysokosprawna chromatografia cieczowa w odwróconym układzie faz została wykorzystana do oznaczania wybranych herbicydów chlorofenoksykwasowych oraz do analizy produktów ich radiolitycznego rozpadu - fenoli i chlorofenoli. Optymalne warunki rozdzielenia otrzymano przy zastosowaniu 60% kwasu octowego (26 mmol -1, ph 2,5) i 40% acetonitrylu jako fazy ruchomej z detekcjąspektrofotometrycznąprzy γ= 280 nm. Granice wykrywalności dla herbicydów i chlorofenoli wynosiły odpowiednio 19-41 μ L-1 i 10-60 μg L-1.Opracowana metoda została wykorzystana do monitorowania wpływu wielkości dawkipromieniowania na proces rozkładu powszechnie stosowanych herbicydów MCPA i dikamby.

5

Application of ionizing radiation for degradation of organic pollutants in waters and wastes

75%

Drzewicz P. , Bojanowska-Czajka A. , Trojanowicz M. , Nałęcz-Jawecki G. , Sawicki J. , Wołkowicz S.

Polish Journal of Applied Chemistry

|

2003

|

tom Vol. 47, nr 3

127-136

EN

The use of ionizing radiation ? or electron beam is a very effective technology of advances oxidation. It can be successfully applied in removal of various organic pollutants from water and wastes. As examples of this technology the decomposition of chlorophenols and selected pesticides is shown. The effectiveness of this method depends on kind of radiation used, employed dose and the presence of radiation scavengers in irradiated solution. Because of a large variety of products formed in these processes, the course of processes of radiolytic degradation of organic should be monitored chemically and in terms of toxicity.

PL

Zastosowanie promieniowania jonizującego ? lub wiązki przyśpieszonych elektronów jest bardzo efektywną technologią pogłębionego utleniania. Można ja z powodzeniem zastosować do usuwania różnorodnych zanieczyszczeń organicznych z wód i ścieków. Jako przykład zastosowania tej technologii przedstawiono rozkład chlorofenoli i wybranych pestycydów. Efektywność tej technologii zależy od rodzaju zastosowanego, użytej dawki i obecności zmiataczy promieniowania w napromieniowanym roztworze. Ze względu na różnorodność powstających produktów, przebieg procesów degradacji promieniowaniem jonizującym powinien być kontrolowany zarówno chemicznie jak i toksykologicznie.