Wyniki wyszukiwania - Biblioteka Nauki

1

Dioksyny, furany i polichlorowane bifenyle - toksyczność i występowanie w środowisku

100%

Cieślik I. , Migdał W.

Inżynieria i Ochrona Środowiska

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2012

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tom T. 15, nr 3

237--247

PL

Ksenobiotyki są bardzo dużą grupą związków o strukturalnej budowie podobnej do estrogenów. Ta grupa posiada wiele różnych właściwości chemicznych: zdolność do wywoływania efektów toksycznych, trwałość w środowisku, zdolność do bioakumulacji i transportu atmosferycznego na duże odległości. W pracy analizowano obecność dioksyn, furanów i polichlorowanych bifenyli w środowisku. Została podana ich charakterystyka. Ze względu na wszechobecność dioksyn w środowisku człowieka, wynikającą z działalności przemysłowej i rolniczej (środki ochrony roślin), całkowite wyeliminowanie narażenia ludzi na dioksyny jest praktycznie niemożliwe. Kontrola narażenia na zatrucie dioksynami ma na celu ocenę ryzyka wystąpienia niekorzystnych skutków zdrowotnych, wynikających z narażenia na te związki, i powinna być skoncentrowana na redukcji emisji dioksyn do środowiska i zaniechania procesów technologicznych, będących źrodłami ich powstawania. Została przedstawiona toksyczność tych związków i ich wpływ na zdrowie człowieka. Zostały scharakteryzowane źródła ich występowania w środowisku.

EN

Xenobiotics are a very large group of compounds of structural construction similar to that of estrogen. Within this group occur many different chemical characteristics: the ability to cause toxic effects, persistence in the environment, bioaccumulativeness, and atmospheric transport over long distances. In this study, presence of dioxins, furans and polychlorinated biphenyls in the environment were presented. Their characteristic was given. Due to the omnipresence of dioxins in the human environment resulting from industrial and agricultural activities (pesticides), total elimination of human exposure to dioxins is virtually impossible. Control of exposure to dioxin poisoning aims to assess the risk of adverse health effects resulting from exposure to these compounds and should be concentrated on reducing emissions of dioxins into the environment and stopping processes that are the sources of their formation. The toxicity of these compounds and their effects on human health were presented. Sources of their occurrence in the environment were characterized.

2

Separation of inorganic nanopowders using the concentration gradient method

80%

Cieślik I. , Żmija J. , Ohams M.

Polimery

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2012

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tom T. 57, nr 7-8

558-561

EN

In the present paper a modified method to separate inorganic nanopowders using the concentration gradient method has been presented. Extraction of individual fractions as a non-destructive method has been discussed. The technique in question allows obtaining a grain size that varies from several micrometers down to several nanometers using simple devices and within a short time.

PL

Artykuł przedstawia technikę rozdzielania nanoproszków nieorganicznych za pomocą zmodyfikowanej metody gradientu stężeń na przykładzie boranu glinowo-itrowego. Opisana metoda separacji jest metodą nieniszczącą. Pozwala w krótkim czasie oraz za pomocą prostych urządzeń laboratoryjnych uzyskać frakcje nanocząstek o rozmiarach od kilkunastu mikrometrów do kilku nanometrów.

3

Synthesis and characteristics of optical properties of crystalline YAl3(BO3)4:Cr,Ce

61%

Cieślik I. , Żmija J. , Majchrowski A. , Pępczyńska M. , Morawiak P. , Włodarski M.

Journal of Achievements in Materials and Manufacturing Engineering

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2011

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tom Vol. 48, nr 1

24--28

EN

Purpose: The purpose of this study is to explore the possibility of conrol the grain size of YAB nanopowder and to investigate the optimum amount of dopant cerium or chromium ions in the matrix of YAB for luminescent intensity. Design/methodology/approach: Nanocrystalline samples of YAB were prepared by sol-gel method and calcination at 1273 K. The structure and morphology of nanopowders were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and aerodynamic aerosol aerodynamic methods. Fluorescent intensity was measured by Fourier transform infrared (FTIR) and intersection of three-dimensional matrix (EM-EX) methods. Findings: It was confirmed that the mean size of the obtained particles depended on the chain length of the precursor polimer used for reaction. The luminescence of YAB doped with cerium and chromium ions was measured. Research limitations/implications: The results can be used in order to further develop sol-gel technology to obtain pure and doped YAB nanopowder. Originality/value: Single phase crystalline YAB synthesis was developed. The measurements XRD confirmed that doping of YAB with some of RE or TM ions favours the formation of additional phase YBO3, having the orgonic structure.

4

Control of optical active borates nanocrystals agglomeration

61%

Cieślik I. , Węgłowski R. , Żmija J. , Kurzydłowski K. , Płocińska M. , Oćwieja M.

Journal of Achievements in Materials and Manufacturing Engineering

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2013

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tom Vol. 61, nr 2

163--168

EN

Purpose: The purposes of this study explore the possibility of total control the agglomeration of nanoborates powders. The great potential of PDLCs can be enhanced by using dye-doped or nanoparticles-doped materials, such as borates [1]. It is important to know how to prepare nanoparticles in order to obtain a high level of dispersion in the composites. Otherwise, even small an agglomeration does not give a possibility on the appropriate characteristic of properties and interpretation of the results. The deagglomeration methods applied until now give the decrease of agglomeration to a lesser extent than our method. Characteristic size and shape of particles made with sol-gel process is difficult to perform. Design/methodology/approach: Nanopowders samples of YAB and LCBO were prepared with sol-gel method. Deagglomeration process was carried out using acetic acid. The morphology and size of nanopowders were investigated by scanning electron microscopy (SEM). The crystallite sizes were determinated with IPS UA method. Findings: It was confirmed that the acetic acid influence on the decrease of agglomeration. It was also determined of conditions for preparation borates nanopowders samples (concentration acetic acind time and temperature of drying prepared samples). We have proved that a reagent used for deagglomeration process does not affect the structure of the investigated nanoborates used in an experimental. Research limitations/implications: The results can be used to the prepared of nanocompades of borates to observe a morphology and reliable assessment of nanocrystalline size. Originality/value: Our study shows how to prepare a sample of particles to observe morphology and measure the size of nanograins. In our study we found excellent solution, the medium, which not influence the inorganic nanomaterial structure. Result seems to be excellent and very perspective. We have showed as that measurement type influence the results of particles size.