Wyniki wyszukiwania - BazTech

1

The influence of electron and gamma irradiation on the properties of starch : PVA films : the effect of irradiation dose

Cieśla Krystyna A., Abramowska Anna

Nukleonika

|

2021

|

Vol. 66, No. 1

3--9

EN

The paper discusses the effect of ionizing radiation on the functional properties of the biodegradable starch:PVA films. The analysis is related to the possible use of the material for packing the products (particularly, food) that are predicted for radiation decontamination and to the potential modifi cation of the material by radiation treatment. Our previous results have shown that the infl uence of ionizing radiation on the films’ properties varied for the specific compositions (differing in starch:PVA ratio or the type of substrates) and depended on irradiation conditions. However, these studies considered only the irradiation performed in gamma chamber or in e-beam using a dose of 25 kGy. Therefore, the present study deals with the effect of the irradiations performed using various doses on the selected promising starch:PVA composition. The films characterized by starch:PVA weight ratio of 45:55 was obtained by solution casting and irradiated with fast electrons in air and with 60Co gamma rays in nitrogen applying the doses of 5, 10, 20, 25, 30, 50, and 75 kGy. No regular dependence has been noticed between the composition of films (differing in the starch and PVA content) and the intensities of the particular bands in the UV-VIS DRS spectra after irradiation. The results indicated strong interaction of the starch and PVA components in the films and the occurrence of specific reactions in each composition upon irradiation. No special differences were observed between tensile strength and Young’s modulus of the non-irradiated films characterized by the starch:PVA ratio equal to 45:55 and the samples irradiated using doses in the range of 5–75 kGy. Similarly, no differences were observed in both cases between the swelling capability of the non-irradiated and the irradiated films. However, it can be deduced that solubility in water increased when the radiation dose increased. The results show that using the doses till the range 25 kGy does not cause an essential change of all the examined properties of the starch:PVA (45:55) films. Accordingly, starch:PVA (45:55) films might be considered suitable for packing food predicted for radiation decontamination.

2

Badania własności optycznych cienkich warstw

Tański T., Matysiak W., Jarka P.

LAB Laboratoria, Aparatura, Badania

|

2018

|

R. 23, nr 2

14--16

3

Oddziaływanie dihydroksyacetonu (DHA) zawartego w samoopalaczach z ludzką skórą – badania spektroskopowe i teoretyczne

Pietruś W., Kurczab R., Latowski D.

Tarnowskie Colloquia Naukowe. Nauki Techniczne i Ścisłe

|

2017

|

T. 4, nr 3

79--90

PL

Celem pracy było zbadanie wybranych właściwości ośmiu samoopalaczy różniących się konsystencją i zawartością dihydroksyacetonu (DHA). Badane bronzery podzielono na trzy grupy: płynne produkty samoopalające zawierające około 15% DHA, półpłynne samoopalacze (spryskiwacze lub pianki) oraz bronzery w postaci kremu. Produkty z tych dwóch ostatnich grup zawierały około 5% DHA. Badanie miało na celu sprawdzenie, czy samoopalacze są w stanie absorbować promieniowanie UV. Celem zastosowania spektroskopii w podczerwieni było zbadanie wpływu samoopalaczy na poziom nawilżenia skóry. W trakcie pracy wykonano obliczenia kwantowo-mechaniczne. Obliczenia dotyczyły komputerowego modelowania przepuszczalności DHA przez warstwę beta-keratyny skóry. Obliczono również energię wiązania wodorowego pomiędzy łańcuchami beta-keratyny oraz powierzchnię wykrystalizowanej formy beta-keratyny. Wyniki badań wykazały, że DHA bardzo silnie absorbował promieniowanie UV-C, natomiast w mniejszym stopniu promieniowanie UV-B. Najmniejsza absorbancja została zarejestrowana w zakresie promieniowania UV-A. Płynne i częściowo półpłynne samoopalacze obniżyły poziom nawilżenia skóry, natomiast produkty w postaci kremu zawierały substancje nawilżające, które neutralizowały negatywny wpływ DHA na nawilżenie skóry. W badaniach in silico wykazano, że DHA nie przenika przez warstwę beta-keratyny skóry. Potencjalnymi przyczynami mogą być duże ilości energii wiązań wodorowych i naładowana powierzchnia beta-keratyny.

EN

The purpose of this study was to investigate selected properties of eight bronzers differing in consistency and dihydroxyacetone (DHA) content. The investigated bronzers were divided into three groups including: liquid sunless tanning products containing DHA level of about 15%, half-liquid self-tanners (spray or foam), and bronzers in the form of a cream. The products from the two latter groups contained about 5% DHA. This study inspected if self-tanners have the ability to absorb UV radiation. The aim of using infrared spectroscopy was to investigate the influence of self-tanners on skin moisture level. During the study, quantum-mechanical calculations were done. The calculations were related to computer-based modeling of DHA permeability through the beta-keratin layer of the skin. The calculations were also done to estimate hydrogen bond energy between chains of the beta-keratin as well as the surface of the crystallized beta-keratin surface. The results indicated that DHA absorbed UV-C radiation very strong, whereas UV-B radiation was absorbed to a lower degree. The least absorbancy was discovered in the UV-A range. Liquid and, partly, half-liquid self-tanners reduced skin moisture; however, products in the form of cream contained moisturizing substances that neutralize the negative effect of DHA on skin hydration. In silico studies indicated that DHA does not permeate through the beta-keratin layer of the skin. Potential reasons for this may be the large energy of hydrogen bonds and charged beta-keratin surface

4

Różnicowanie barwy pojedynczych włókien bawełnianych w badaniach kryminalistycznych

Starczak R., Wąs-Gubała J., Kościelniak P.

LAB Laboratoria, Aparatura, Badania

|

2014

|

R. 19, nr 1

16--20

PL

W pracy przedstawiono zastosowanie metody mikrospektrofotometrii (MSP), zarówno w zakresie UV jak i Vis do rozróżniania fragmentów włókien bawełnianych barwionych barwnikami reaktywnymi, pochodzącymi od jednego producenta. Omówiono również możliwości oceny stężenia barwnika w badanym włóknie na podstawie analizy przebiegu otrzymanych widm, a także występowanie zjawiska dichroizmu w trakcie prowadzenia badań włókien.

5

Soil pollution of selected PHAs as a factor affecting the properties of humic acids

Dębska B., Banach-Szott M, Rosa E.

Journal of Ecological Engineering

|

2014

|

Vol. 15, nr 1

67--73

EN

It is well-known that the properties of humus soil substances (including humic acids) are soil-type-specific. However, one shall consider the fact that properties of organic matter of soil can be modified by farming system (crop rotation, fertilisation) as well as other external factors, including pollutants; PAHs. The objective of the paper is to determine the effect of a single-time pollution of soils with high rates of PAHs on the properties of humic acids. The research was performed with the samples of soils representative for the Kujawy and Pomorze Region (Phaeozems, Luvisol, Haplic Arenosols, Fluvisols). Soil samples were polluted with selected PAHs; fluorene, anthracene, pyrene and chrysene at the amount corresponding to 100 mg PAHs kg-1. Treatments, i.e., soils + PAHs, were incubated for 180 and 360 days at the temperature of 20–25 ºC and at constant moisture of 50% of field water capacity. Humic acids were extracted from the soil samples prior to and after 180 and 360 days of incubation. The following analyses were performed for separating humic acids: elemental composition, UV-VIS and IR spectrophotometric analyses, susceptibility to oxidation. Results demonstrated that a single introduction of fluorene, anthracene, pyrene and chrysene at very high rates into soils affects the properties of humic acids. There was mostly recorded a de-crease in coefficients of absorbance A2/6 and A4/6, an increase in the parameter defining the susceptibility of humic acids to oxidation. There were also noted changes in the pattern of spectra in infrared and the values of the parameter defining the degree of internal oxidation of the humic acids molecules.

6

Synthesis and optical characteristics of silver nanoparticles on different substrates

Budhiraja N., Sharma A., Dahiya S., Parmar R., Vidyadharan V.

International Letters of Chemistry, Physics and Astronomy

|

2013

|

Vol. 14

80--88

EN

Silver nanoparticles have been deposited on glass and polyethylene substrate by Chemical Bath Deposition (CBD) technique and Chemical rolling method. A comparative study has shown that Chemical bath technique is superior compared to rolling technique for uniform deposition of silver nanoparticles on glass substrate. Crystallography investigation of these materials is done by X-ray diffraction (XRD) which reveals that average grain size is in nano region. Scanning Electron Microscope (SEM) is used for topography study of these prepared nanostructures. Optical properties of the synthesized materials are studied by UV-VIS in detail to check their potential for next era industrial revolution.

7

UV-VIS and FTIR Investigations of Long-Term Aged Explosives. Part 1

Shishkov P., Nedkova M., Atanasova P.

Central European Journal of Energetic Materials

|

2011

|

Vol. 8, nr 4

293-301

EN

An investigation of TD-50 and tetryl samples obtained by dismantling of weapons, made in 1961 in Bulgaria, was carried out. The weapons were stored in non-heated military stores and the explosives were aged in this time (50 years). The results from UV-VIS and FTIR spectroscopy showed the formation of H-bonds in the solutions and in the investigated materials. The most available properties for determination of H-bond formation from UV-VIS spectra were: the shift, (Δ λ); ratio shift/dilution, (Δ λ /C1/Cn, nm, and Δ λ/Δ C, nm.ml/mg) in acetone solutions and only the shift, (Δ λ) in toluene solutions. The results from FTIR spectroscopy showed that the most available for determination of H-bond formation were: absorbances of some maxima for -NO2 groups, divided from maxima for -CH2 at 917 and 715 cm-1 like internal standards and some values of Δh*1/2.

8

UV-VIS and FTIR Investigations of Long-Term Aged Explosives. Part 2

Shishkov P., Nedkova M., Atanasova P., Glavchev I.

Central European Journal of Energetic Materials

|

2011

|

Vol. 8, nr 4

303-310

EN

Samples of long-term aged TD-50 and tetryl were investigated by UV-VIS and FTIR spectroscopy and bands of products of ageing were obtained. A complicated maximum of nitro groups at 1537 cm-1 in the FTIR spectra of long-term aged explosives was obtained, like in the IR spectra of long-term aged single-based propellants. Ageing process was confirmed by the presence of several maxima in UV-VIS and FTIR spectra of aged products and determination of several characteristics of the investigated explosives (shifts Δ ν, differences in absorbances ΔA, differences in values of Δh*1/2). Ageing was connected with decrease of H-bond formation on the base of decrease of content of oxygen and nitro groups in TD-50 and tetryl.

9

Polyaniline based dual system for potentiometric or UV-VIS spectrophotometric alkaline phosphatase detection

Malinowski P., Michalska A., Maksymiuk K.

Chemia Analityczna

|

2009

|

Vol. 54, No. 3

415-425

EN

A simple disposable conducting polymer - polyaniline based system for the alkaline phos- 1 phatase activity determination either in potentiometric or UV-VIS spectrophotometric setup is described. The conducting polymer was placed on a plastic polyacetate support by disper-; sing polyaniline nanoparticles. The detection method used is based on the enzymatic hydrolysis of monofluorophosphate which leads to a decrease of sample pH and finally results in a measurable change in the polyaniline electrode potential or the absorption spectra of the polymer. Both techniques offer similar sensitivity, but for the potentiometric mode a lower detection limit was obtained; it was close to 30 U L-1 (below 1 mgL-1).

PL

Opisano proste czujniki jednorazowego użytku, wykorzystujące polimer przewodzący - polianilinę, umożliwiające oznaczanie fosfatazy alkalicznej techniką potencjometrii i spektrofotometrii UV-VIS. Polimer przewodzący naniesiono z zawiesiny nanocząstek polianiliny na podłoże z folii polioctanowej. Metoda detekcji wykorzystuje enzymatyczną hydrolizę anionów monofluorofosforanowych, prowadzącą do obniżenia pH i w rezultacie do mierzalnej zmiany potencjału elektrody polianilinowej lub zmiany widma absorpcyjnego polimeru. Obie techniki zapewniaj ą podobną czułość, lecz dla metody potencjometrycznej uzyskano niższą granicę wykrywalności, bliską 30 UL-1 (poniżej l mgL-1).

10

Information Content in Linear Dichroism Spectra

Thulstrup P. W.

Polish Journal of Chemistry

|

2008

|

Vol. 82, nr 4

901-920

EN

Spectroscopy with linearly polarized light on aligned samples (LD spectroscopy) is a useful technique that may greatly enhance the possibilities for determining sample structure, making spectral assignments, and several other tasks, generally based on a determination of transition moment directions. However, the technique does not provide the same amount of information in all cases; this depends strongly on the molecular symmetry. The almost ideal case is that of D2h, D2, or C2v symmetry, when only 3 different (perpendicular) transition moment directions are possible. When the molecular symmetry decreases, the information that may be obtained becomes less precise. If the molecule has a plane of symmetry left, the transition moment may be located perpendicular to the symmetry plane or at any direction in the plane, and much useful information may still be extracted. In the case of a molecule with no symmetry at all the information that can be obtained often becomes highly qualitative, unless special information happens to be available. Unfortunately, this severe limitation is sometimes overlooked when low-symmetry molecules are studied, and the spectra are evaluated the same way spectra for symmetrical molecules are. This is an obvious source of error, and conclusions based on such an analysis are hardly reliable. In this paper, the spectroscopic technique, assumptions commonly made, and the mathematical treatment of IR and UV spectra are briefly summarized for different molecular symmetries. This is illustrated by a few examples, including new IR LD spectra of limonene, a very difficult, low symmetry case.

11

Thin PPI films doped with iron (III) chloride

Hajduk B., Weszka J., Jurasik J., Jarząbek B.

Zeszyty Naukowe Politechniki Poznańskiej. Budowa Maszyn i Zarządzanie Produkcją

|

2007

|

Nr 4

65-69

EN

Optical spectra were recorded on polyazomethine thin films pristine and doped with iron (III) chloride. Doping process is seen to smear the absorption edge in UV-VJS spectra, which is attributed to polaron states formation. Positive polaron states appear within the forbidden gap of PPI, above valence band. Thopographic AFM images have shown variation in films morphology connected with surface granulation and RMS changes.

PL

W artykule przedstawiono wyniki badań optycznych wykonanych na cienkich warstwach poli-azometiny PPI, czystych i domieszkowanych chlorkiem żelaza (III). W widmach optycznych domieszkowanie powoduje rozmycie krawędzi absorpcji, które przypisuje się wytworzeniu stanów potaronowych w przerwie energetycznej polimeru. W widmie widoczne są jako progresje wi-broniczne o energii mniejszej niż szerokość pasma zabronionego. Zdjęcia topograficzne AFM wykazują że powierzchnie warstw domieszkowanej! niedomieszkowanej maja inną wielkość uziarnienia. a także różnią się współczynnikiem nierówności powierzchni RMS.

12

Optimization of extraction of pyrrolizidine alkaloids from plant material

Mroczek T., Widelski J., Głowniak K.

Chemia Analityczna

|

2006

|

Vol. 51, No. 4

567-580

EN

Various techniques of extraction of pyrrol izidine alkaloids (PAs) from comfrey have been developed and compared. Different extraction media: methanol, ethanol, 1% methanolic solution of tartaric acid, 2.5% HC1 solution, 5% CH.COOH solution, alkaline chloro form- -methanol mixture at various temperatures (room temperature, 50-60°C, solvent's boiling point) have been used in various extraction techniques (percolation, electric basket, ultrasonic water bath) and various extraction times. Total concentration of pyrrolizidine alkaloids (PAs) was estimated from UV-VIS spectrophotometric studies according to Dann- -Mattocks procedure. For the most promising extraction techniques one determined recoveries of monocrotaline added to crude pre-extracts. Extraction and co-extraction processes were investigated using UV-VIS spectra of the adducts of 3,4-dehydro-PAs and Ehrlich's reagent. The best result of PAs extraction from comfrey was obtained using 1% methanolic solution of tartaric acid and electric basket technique at the temperature 100 š 5°C for 2 h. Possible applications of the method have been discussed.

PL

W prezentowanej pracy podjęto badania optymalizacji ekstrakcji alkaloidów pirolizydy-nowych (PAs) z materiału roślinnego (źywokostu lekarskiego). Zastosowane metody obejmowały ekstrakcję metanolem, etanolem, l % roztworem kwasu winowego w metanolu, 2.5% roztworem kwasu solnego, 5% roztworem kwasu octowego, alkaliczną fazą organiczną (chloroform-metanol). Badano również wpływ temperatury ekstrakcji (pokojowa, 50-60°C, wrzący rozpuszczalnik) wykorzystując różne techniki ekstrakcyjne (perkolacja, ekstrakcja w płaszczach grzewczych, ekstrakcja wspomagana ultradźwiękami) oraz wpływ czasu ekstrakcji na odzysk PAs z surowca roślinnego. Caikowitą zawartość PAs oznaczono w oparciu o spektrofotometrię UV-VIS wg metody Danna i Mattocksa. W przypadku najbardziej obiecujących metod ekstrakcji oznaczono odzysk wzorca monokrotaliny dodawanego do pre-ekstraktu tuż przed rozpoczęciem właściwej ekstrakcji. Analizując widma U V—VIS adduktów 3,4-dehydro-PAs z odczynnikiem Ehrlicha możliwa była analiza stopnia ekstrakcji PAs z surowcajak i współekstrakcji substancji balastowych. Najlepszą wydajnością oraz najmniejszym stopniem współekstrakcji balastów charakteryzowała się 2-godzinna ekstrakcja wrzącym (temp. 100 š 5°C) 1% roztworem kwasu winowego w metanolu w płaszczach grzewczych. Przedyskutowano także potencjalne wykorzystanie opracowanej metody.

13

Spectrophotometric micro assay for determination of 2-furaldehyde in transformer oils

Rodriguez D. M., Wrobel K., Wrobel K.

Chemia Analityczna

|

2005

|

Vol. 50, No. 1

315-326

EN

In this work, a spectrophotomelric micro assay has been proposed for the determination of 2-furaIdehyde (2-PAL) in transformer oil. This compound is a degradation product of cellulose-based Kraft paper, which is used for insulation of transformer conductive elements. 2-FAI, has been accepted as the primary chemical indicator o f paper degradation and its determination is necessary in controlling the actual condition of transformer in use. For spectrophotometric measurements, a pink-colored /T-charge transfer complex of 2-FAL with aniline acetate was formed (ε = 23500 L mol-1>cm-1>). The original idea was to enhance overall sensitivity (including preconcentration step) of the previously reported procedures by means of the complex extraction to glacial acetic acid. A micro scale analysis was proposed to reduce the sample volume (1 mL) and to lower the amount of reagents and solvents required (100 μL of aniline, 5% in chloroform and 200 μ of glacial acetic acid). To reduce the effect of sample turbidity, analytical signal was defined as the difference between the absorbances measured at 519 nm (maximum of the complex absorption band) and 594 nm (beyond the spectral band of complex). Within the calibration range 0.1-1.0 mg L-1 R2 value was 0.997. The quantification limit was 34 μg L -1;R2relative standard deviations at two levels of 2-FAL concentration (0.4 and 0.8 mg L-1) respectively 9.8% and 5.5%: and the recovery obtained in the analysis of fortified sample (0.4 mg L-1) was 95š6%. Analytical results of the proposed procedure were compared with those obtained by high perfor mance liquid chromatography with pre-column derivatization (2,4-dinitrophenylhydrazine). In this case, the following aldehydes were also included: 5-hydroxymelhyl-2-furaldehyde, formaldehyde, acetaldehydc, benzaldehyde and 5-methyl-2-furaldehyde, as the possible degradation products of insulation elements (paper and mineral oil).

PL

W niniejszej pracy przedstawiono dwie procedury oznaczania 2-furaIdehydu (2—FAL) w oleju transformatorowym. Wymieniony związek jest produktem rozkładu papieru Krafta, który jest stosowany do izolacji zwojów transformatora. 2-FALjest szeroko stosowany jako chemiczny wskaźnik stopnia zużycia papieru izolującego i oznaczanie jego zawartości w oleju transformatorowym jest elementem kontroli pracującego transformatora. W procedurze wykorzystano opisane w literaturze powstawanie barwnego kompleksu z octanem aniliny ((ε=23500 L -1>cm-1>) Oryginalną ideą było zastosowanie ekstrakcji kompleksu do fazy lodowatego kwasu octowego, co pozwoliło zwiększyć czułość całej procedur) w porównaniu z wcześniejszymi doniesieniami literaturowymi. Zastosowanie mikro skali pozwoliło na użycie niewielkiej ilości próbki (1 m L) i odczynników (1OO μL 5% aniliny w chloroformie i 200 μL lodowatego kwasu octowego) a także wytwarzanych odpadów. W celu zmniejszenia wpływu zmętnienia próbki, sygnał analityczny zdefiniowano jako różnicę absorbancji mierzonych przy 519 nm {maksimum pasma absorpcji kompleksu) i 594 nm (poza pasmem absorpcji). Kalibrację wykonano w zakresie stężeń 2-FAL 0.1-1.0 mg L-1, uzyskując wartość współczynnika korelacji liniowej 0.997. Wartość wyznaczonej granicy oznaczalności wynosiła 34 μg L-1; względnych odchyleń standardowych dla dwóch poziomów stężenia analitu (0.4 and 0.8 rng L-1-1

14

Wykorzystanie metody wzorca wewnętrznego w wieloetapowych procedurach spektrofotometrii UV/VIS

Wróbel K., Wróbel K.

Analityka : nauka i praktyka

|

2001

|

nr 1

4--6

PL

Jednym z kluczowych punktów w opracowaniu nowej procedury analitycznej jest wybór odpowiedniej metody kalibracji, ponieważ od tego etapu w dużej mierze zależy dokładność i precyzja wyników oznaczenia.

15

Reactivity of cis-Diaminedichloroplatinum(II) (cis-Platin) Toward Chromium(IV)

Stawińska J., Staszak Z., Jezierska J., Cieślak-Golonka M., Daszkiewicz M.

Polish Journal of Chemistry

|

2000

|

Vol. 74, nr 3

291-301

EN

The interaction of Cr(VI) compounds: K2Cr2O7 with cis-diaminedichlorplatinum(II) (cis-Platin) has been studied spectroscopically (UV-VIS, IR, FIR, ESR). It was found that the redox processes took place with the precipiation of brown Pt(IV)-Cr(III) heteropolynuclear products. The deconvolution of the electronic spectra allowed the analysis in convention of independent Pt(IV) and Cr(III) crystal fields.

16

New Polymeric Copper(II) Complexes with Triphenyl Phosphite and Perfluorinated Carboxylates

Szłyk E., Szymańska I., Wrzeszcz G., Rozpłoch F.

Polish Journal of Chemistry

|

2000

|

Vol. 74, nr 7

909-918

EN

New Cu(II) complexes with triphenyl phosphite and aliphatic perfluorinated carboxylates [Cu{P(OC6H5)3}(u-OH)(u-RCOO)]n (where R=CF3, C2F5, C3F7, C6F13, C7F15, C8F17, C9F19) were obtainedf and their spectroscopic and thermal properties studied. EPR spectra and magnetic susceptibility measurments indicate the formation of polymeric complexes. Examination of COO absorption bands suggests bridging carboxylates as well as a hydro group, whereas triphenyl phosphite is monodentately bonded. Thermal decomposition is a multistage process, which in nitrogen yields a mixture of Cu, Cu2O and Cu2p2O7 but in air - pure u2P2O7.

17

Nowoczesna analiza QA/QC przy wykorzystaniu spektroskopii FT NIR. Cz. 2: Metodyka kalibracji PLS w spektroskopii NIR w badaniach ilościowych

Leszczyński W., Marek D.

LAB Laboratoria, Aparatura, Badania

|

2000

|

R. 5, nr 4

28-32