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Short-term changes in thermal conditions and active layer thickness in the tundra of the Kaffiøyra region, NW Spitsbergen

., GAWOR Ł, BUDZIK T., KLEMENTOWSKI J., 2013, Variability of temperature and thickness of permafrost active layer at coastal sites of Svalbard. Polish Polar Research, 34(4): 353-374. ETZELMÜLLER B., SCHULER T.V., ISAKSEN K., CHRISTIANSEN H.H., FARBROT H., BENESTAD R., 2011, Modeling the temperature evolution of Sval bard permafrost during the 20th and 21st century. The Cryosphere, 5: 67-79. GRZEŚ M., 1985, Warstwa czynna wieloletniej zmarzliny na zachodnich wybrzeżach Spitsbergenu. Przegląd Geograficzny, LVII (4): 671

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Ground thermal regime on the Kaffiøyra Plain (NW Spitsbergen) in the period from 1 September 2012 to 31 August 2014

, The local wind field at Ny-Ålesund and the Zeppelin mountain at Svalbard. Meteorology and Atmospheric Physics, 78: 107–113. BROWN J., HINKEL K.M., NELSON F.E., 2000, The circumpolar active layer monitoring (CALM) program: research designs and initial results. Polar Geography, 3: 165–258. FØRLAND E.J., BENESTAD R., HANSSEN-BAUER I., HAUGEN J.E., SKAUGEN T.E., 2011, Temperature and precipitation development at Svalbard 1900–2100. Advances in Meteorology, Article ID 893790: 1–14. GAVRILOVA L. A., SOKOLOV S. I., 1969, Vremennaya izmentchivost

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Pervaporative desulfurization of gasoline – separation of thiophene/n-heptane mixture / Perwaporacyjne odsiarczanie benzyny – separacja mieszanin tiofen/n-heptan

Abstract

This paper presents the recent advances in pervaporative reduction of sulfur content in gasoline. Methods of preliminary selection of membrane active layer material are presented. Interactions between gasoline components (typical hydrocarbon and sulfur species) and membranes are showed. Influence of pervaporation process parameters i.e. feed temperature, downstream pressure and feed flow rate on the separation efficiency is discussed. Investigations of the influence of sulfur concentration in fluid catalytic cracking (FCC) gasoline on membrane performance have been conducted. A series of PV tests was carried out to investigate the separation properties of the commercial composite membrane with an active layer made of poly(dimethylsiloxane) and to determine the efficiency of organic sulphur compound (thiophene) removal from model thiophene/n-heptane mixture depending on its concentration.

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Hole transport in organic field-effect transistors with active poly(3-hexylthiophene) layer containing CdSe quantum dots

Abstract

Hybrid field-effect transistors (FETs) based on poly(3-hexylthiophene) (P3HT) containing CdSe quantum dots (QDs) were fabricated. The effect of the concentration of QDs on charge transport in the hybrid material was studied. The influence of the QDs capping ligand on charge transport parameters was investigated by replacing the conventional trioctylphosphine oxide (TOPO) surfactant with pyridine to provide closer contact between the organic and inorganic components. Electrical parameters of FETs with an active layer made of P3HT:CdSe QDs blend were determined, showing field-effect hole mobilities up to 1.1×10−4 cm2/Vs. Incorporation of TOPO covered CdSe QDs decreased the charge carrier mobility while the pyridine covered CdSe QDs did not alter this transport parameter significantly.

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Graphene as a Material for Solar Cells Applications

Abstract

Graphene is a two-dimensional material with honeycomb structure. Its unique mechanical, physical electrical and optical properties makes it an important industrially and economically material in the coming years. One of the application areas for graphene is the photovoltaic industry. Studies have shown that doped graphene can change one absorbed photon of a few electrons, which in practice means an increase in efficiency of solar panels. In addition, graphene has a low coefficient of light absorption 2.3% which indicates that is an almost completely transparent material. In fact, it means that solar cells based on graphene can significantly expand the absorbed spectrum wavelengths of electromagnetic radiation. Graphene additionally is a material with a very high tensile strength so it can be successfully used on the silicon, flexible and organic substrates as well. So far, significant effort has been devoted to using graphene for improving the overall performance of photovoltaic devices. It has been reported that graphene can play diverse, but positive roles such as an electrode, an active layer, an interfacial layer and an electron acceptor in photovoltaic cells. Research on solar cells containing in its structure graphene however, are still at laboratory scale. This is due to both lack the ability to produce large-sized graphene and reproducibility of its parameters

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Determining optimum wavelength of ultraviolet rays to pre-exposure of non-uniformity error correction in Gafchromic EBT2 films

Abstract

Gafchromic films have been used to measure X-ray doses in diagnostic radiology such as computed tomography. The double-exposure technique is used to correct non-uniformity error of Gafchromic EBT2 films. Because of the heel effect of diagnostic x-rays, ultraviolet A (UV-A) is intended to be used as a substitute for x-rays. When using a UV-A light-emitting diode (LED), it is necessary to determine the effective optimal UV wavelength for the active layer of Gafchromic EBT2 films. This study evaluated the relation between the increase in color density of Gafchromic EBT2 films and the UV wavelengths. First, to correct non-uniformity, a Gafchromic EBT2 film was pre-irradiated using uniform UV-A radiation for 60 min from a 72-cm distance. Second, the film was irradiated using a UV-LED with a wavelength of 353-410 nm for 60 min from a 5.3-cm distance. The maximum, minimum, and mean ± standard deviation (SD) of pixel values of the subtraction images were evaluated using 0.5 inches of a circular region of interest (ROI). The highest mean ± SD (8915.25 ± 608.86) of the pixel value was obtained at a wavelength of 375 nm. The results indicated that 375 nm is the most effective and sensitive wavelength of UV-A for Gafchromic EBT2 films and that UV-A can be used as a substitute for x-rays in the double-exposure technique.

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Ultraviolet ray irradiation duration for the pre-exposure of Gafchromic EBT2

Abstract

The strength and density change of the ultraviolet (UV) ray of Gafchromic EBT2 were investigated. Previous studies suggested that UV-A rays can be substituted for the x-ray double-exposure technique to correct Gafchromic EBT2’s non-uniformity error. In this study, we aimed to determine the appropriate strength of UV-A rays for irradiating an active layer that would correct the non-uniformity error of Gafchromic EBT2.

UV-A rays with a wavelength of 375 nm were used to irradiate Gafchromic EBT2 in various durations, and the resulting density change was investigated. To correct Gafchromic EBT2’s non-uniformity error, a pre-irradiation with a UV-A lamp was conducted at a distance of 72 cm for 30 min. To determine the most appropriate irradiation duration, a UV light-emitting diode generating UV-A of 375 nm was used to irradiate the Gafchromic EBT2 film with varying durations of 1, 2, 3, 4, 5, 10, 15, 20, 25, and 30 min at a distance of 5.3 cm. A 12.7 diameter region of interest was set by the irradiation area, and a histogram of pixel values was created. The condition options were decided based on two important requirements: 1) no zero values of the mode and seconds exist, and 2) the 1/10 value of the mode intersects both histogram sleeves.

In the case of Gafchromic EBT2, the irradiation strength was 85.43 mJ/cm2 for one minute in which the pixel value of mean ± SD was 255.34 ± 213.29. The irradiation duration of 4 min was the border duration of the above two conditions. When a UV ray of 375 nm wavelength is used to irradiate Gafchromic EBT2 as a substitute for x-ray exposure, the 4-min pre-irradiation duration (341.74 mJ/cm2) is demonstrably sufficient.

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Analysis of Catalitic Reactors Usefulness to Reduce Pollution Generated by Piston Combustion Engines with Regard to Ship Main Engines

Abstract

The article presents results which indicate that the use of catalytic reactors to reduce emissions of harmful compunds contained in the exhaust gas is important in the operation of vehicle motors operation. Efforts of the shipbuilding industry to reduce the toxicity of exhaust gas emitted by the main engines have been indicated and pointed to the desirability of the use of these catalysts in maritime transport. It has been pointed out that studies of the harmful substances in exhaust gases performer at vehicle inspection stations have an impact on increasing the safety of drivers and other road users and contribute to preserving the natural environment by reducing the danger coming from cars operating on Polish roads. An opinion has been expressed that the most serious threats to the environment are emitted by car transport exhaust fumes, which are characterized by significant emission of toxic compounds excreted into the atmosphere from tailpipe emissions.

It has been demonstrated that a fully functioning catalytic reactor, operating in a steady state at appropriate temperatures and the composition of the mixture close to stoichiometric ratio, can reduce emissions of carbon monoxide, hydrocarbons and nitrogen oxides by more than 90%. Also, an assessment has been presented reporting the efficiency of catalytic reactors of spark ignition engines operating in a test vehicle inspection station. The results of research in the evaluation of their performance were correlated with their operation waveforms. Such an approach is justified by the fact that during the operation of each vehicle the wear of its assemblies and components is different - including the catalytic reactor. The catalytic layer undergoes aging so that there are changes in the structure and chemical composition of the catalyst bed, while the overlapping of layers of different chemical compounds that block access to the active layer of the reactor.

An opinion has also been expressed that it would be advisable to take steps to use research results presented in this article for research of catalytic reactors similar use in diagnostic systems of marine combustion engines, especially the main ones, which exhaust emissions are incomparably greater than in the case of car engines.

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Surface Morphology of Polyimide Thin Film Dip-Coated on Polyester Filament for Dielectric Layer in Fibrous Organic Field Effect Transistor

(12): p. H995-H998. [29] Kim, J., et al., All-solution-processed bottom-gate organic thin-film transistor with improved subthreshold behaviour using functionalized pentacene active layer. Journal of Physics D-Applied Physics, 2009. 42(11). [30] Choi, M. H., et al., Effect of active layer thickness on environmental stability of printed thin-film transistor. Organic Electronics, 2009. 10(3): p. 421-425. [31] Someya, T., et al., A large-area, flexible pressure sensor matrix with organic field-effect transistors for artificial skin applications. Proceedings of the

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Application of the new Monte Carlo code AlfaMC to the calibration of alpha-particle sources

). Note on the scattering corrections in 2 πα counting. Appl. Radiat. Isot., 36, 822-824. 8. Deruytter, A. J. (1962). Evaluation of the absolute activity of alpha emitters and of the number of nuclei in thin alpha active layers. Nucl. Instrum. Methods, 15, 164-170. 9. Hutchinson, J. M. R., Lucas, L. L., & Mullen, P. A. (1976). Study of the scattering correction for thick uranium-oxide and other α-particle sources - II: Experimental. Appl. Radiat. Isot., 27, 43-45. 10. Walker, D. H. (1965). An experimental study of the

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