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Wyszukujesz frazę "Denis, Andrzej" wg kryterium: Autor


Tytuł:
Methane steam reforming at low temperature over Ni-MgO-Al2O3 catalysts: activity and resistance to coking
Autorzy:
Pańczyk, Monika
Denis, Andrzej
Stołecki, Kazimierz
Borowiecki, Tadeusz Krzysztof
Wydawca:
Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
Powiązania:
https://bibliotekanauki.pl/articles/763965.pdf  Link otwiera się w nowym oknie
Opis:
The role of MgO as a factor improving the resistance to coking of the alumina supported nickel catalysts in the steam reforming of hydrocarbons is discussed.    A series of catalysts containing variable amounts of MgO, NiO and a constant amount of Al2O3 was prepared by the co-precipitation method. It was found that the specific activity of the catalysts exhibits a broad but not deep minimum for the MgO contents from 8.5 to 27.3 wt.%. At the same time these catalysts reveal a high resistance to coking either in the reaction with methane or with n-butane. The most promising composition, in terms of the activity and simultaneous resistance to the coke formation, was found to be 27.3 wt.% of MgO and 39.0 wt.% of NiO. The analysis of various factors controlling the activity and resistance to coking leads to the conclusion that MgO reduces the catalysts acidity what, in consequence, reduces the rate of coke formation during the reforming reactions. Furthermore, The resistance to coking correlates well with the mean size of nickel crystallites, the same is observed for the specific catalyst activity. 
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studies of potassium-promoted nickel catalysts for methane steam reforming : effect of surface potassium location
Autorzy:
Kotarba, Andrzej
Rawski, Michał
Dmytrzyk, Jaromir
Gołębiowski, Andrzej
Borowiecki, Tadeusz
Stołecki, Kazimierz
Denis, Andrzej D.
Opis:
The effect of potassium addition to the Ni/Al 2 O 3 steam reforming catalyst has been investigated on several model systems, including K/Al 2 O 3 with various amounts of alkali promoters (1–4 wt% of K 2 O), a model catalyst 90%NiO-10%Al 2 O 3 promoted with potassium and a commercial catalyst. The potassium surface state and stability were investigated by means of the Species Resolved Thermal Alkali Desorption method (SR-TAD). The activity of the catalysts in the steam reforming of methane and their coking-resistance were also evaluated. The results reveal that the beneficial effect of potassium addition is strongly related to its location in the catalysts. The catalyst surface should be promoted with potassium in order to obtain high coking-resistant catalysts. Moreover, the catalyst preparation procedure should ensure a direct interaction of potassium with the Al 2 O 3 support surface. Due to the low stability of potassium on -Al 2 O 3 this phase is undesirable during the preparation of a stable steam reforming catalyst.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł
Tytuł:
Practice of geo-radar research in the Republic of Kazakhstan
Autorzy:
Burtyl, Yuri
Kapski, Denis
Czerepicki, Andrzej
Tematy:
georadar
ground penetrating radar
methodology of field studies
radargram
thickness of monolithic layers
cement concrete pavement
asphalt pavement
metodologia badań terenowych
radarogramy
grubość warstw monolitycznych
nawierzchnia z betonu cementowego
nawierzchnia asfaltowa
Pokaż więcej
Wydawca:
Politechnika Warszawska, Wydział Transportu
Powiązania:
https://bibliotekanauki.pl/articles/38955772.pdf  Link otwiera się w nowym oknie
Opis:
The article considers the issues of applying ground penetrating radar (GPR) technologies for engineering purposes concerning subsurface research. It describes the field of application of GPR research during road construction and operation and the advantages and disadvantages of this type of engineering survey. It presents comparative data on the accuracy (inaccuracy) of existing GPR control methods applied to determine the thickness of the monolithic pavement layers in Europe, CIS, and the USA. The main provisions of the GPR survey procedure are described, including four main stages: the analysis of initial materials of surveyed section and equipment preparation; GPR survey; geological verification; processing and interpreting of radargrams; and the preparation of a report. Geophysical works were performed using the geo-radar of the OKO series as part of the road measuring complex DVK-05 on the section of the Astana-Petropavlovsk A-1 highway with cement concrete pavement and on the section of the R-12 "Kokshetau - Atbasar" with asphalt pavement. The example of a radargram and the core sample of a cement concrete pavement taken during geological verification of the thickness of a monolithic layer is presented. Graphs of variation in the thickness of pavement layers by radargrams of longitudinal passages in the indicated road sections with the assumptions about the nature of the heterogeneity of the obtained values are given. The obtained results on the thickness of monolithic layers (cement concrete and asphalt concrete) were assessed on the criteria of quantitative deviation from the required standard value. Recommendations were provided to address positive deviations in the thickness of monolithic pavement layers at various stages of the road survey.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of the sectoral method to improve the efficiency of route passenger transport
Autorzy:
Semtchenkov, Sergey
Kapsky, Denis
Czerepicki, Andrzej
Tematy:
route passenger transport
efficiency of work
sectoral method
bus
tram
trolleybus
electric bus
time of work drivers
unproductive cost of transport operation
trasa transportu pasażerskiego
efektywność pracy
metoda sektorowa
autobus
tramwaj
trolejbus
autobus elektryczny
czas pracy kierowców
bezproduktywny koszt operacji transportowych
Pokaż więcej
Wydawca:
Politechnika Warszawska, Wydział Transportu
Powiązania:
https://bibliotekanauki.pl/articles/60553817.pdf  Link otwiera się w nowym oknie
Opis:
Route passenger transport plays a significant role in cities' life and economic development, providing movement for the population, improving the environmental situation, and improving road safety. Improving the efficiency of route passenger transport is also essential because the taxpayers' tax subsidizes it. The most researched aspects have always been the choice of the passenger capacity of vehicles, management of their filling, and appointment of route intervals. This research aims to increase the efficiency of route passenger transport. This study identifies ways to improve the efficiency of route passenger transport by reducing costs arising from the imperfect allocation of drivers on routes, irrational use of vehicles working hours, and drivers working hours. Such costs are called unproductive costs. The solution to the problem of increasing efficiency is realized by developing the author's sectoral method described in the article. This article discusses the application of the sectoral method to improve the efficiency of route passenger transport based on the improvement of processes related to the organization of passenger transportation, taking into account the characteristics of various types of route passenger transport by organizing the work of drivers on routes. Methods, techniques, and algorithms and their application are considered. The use of the sectoral approach has made it possible to increase the efficiency of route passenger transport and reduce unproductive costs.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Relationships between serum selenium and zinc concentrations versus profibrotic and proangiogenic cytokines (FGF-19 and endoglin) in patients with alcoholic liver cirrhosis
Autorzy:
Prystupa, Andrzej
Kiciński, Paweł
Luchowska-Kocot, Dorota
Błażewicz, Anna
Kurys-Denis, Ewa
Niedziałek, Jarosław
Sak, Jarosław
Panasiuk, Lech
Tematy:
liver cirrhosis
alcohol
selenium
zinc
fibroblast growth factor-19
endoglin
Pokaż więcej
Wydawca:
Instytut Medycyny Wsi
Powiązania:
https://bibliotekanauki.pl/articles/990858.pdf  Link otwiera się w nowym oknie
Opis:
Introduction and objective. Liver cirrhosis is a disease involving the liver parenchyma, which is characterised by fibrosis. and impaired architectonics of the parenchyma with regenerative nodules. The aim of the study was to determine the relationship between stage of alcoholic liver cirrhosis, concentrations of selenium, zinc and profibrotic and proangiogenic cytokines (FGF-19, ENG). Materials and method. The study included 99 patients with alcoholic cirrhosis and 20 healthy subjects. Ion chromatography with UV/VIS detection was used for determination of zinc ions in the previously mineralized serum samples. The measurements of selenium were performed with the ContrAA700 high-resolution continuum source graphite tube atomic absorption spectrometer. ELISA was used to determine concentration of FGF-19 and ENG in serum samples. Results. Concentrations of zinc and selenium were significantly decreased in cirrhotic patients (p<0.001 for both). The highest concentration of FGF-19 was found in Child-Pugh stage C liver cirrhosis patients (806.9±650.3 pg/ml), and was significantly higher than observed in controls (p=0.005) and stage A patients (compensated cirrhosis) (p=0.02). The highest concentration of ENG was demonstrated in the control group (3.24±148 ng/ml) while the lowest in patients with decompensated cirrhosis (7.32±5.39 ng/ml and 7.92±4.18 ng/ml for stage B and C; p=0.03 and p=0.02, respectively). The use of the multiple-variable model demonstrated that the independent factors affecting the concentration of ENG were the concentration of bilirubin (p=0.02), INR (p=0.01) and duration of alcohol abuse (p=0.02). The independent determinants of FGF-19 concentrations were found to be the stage (severity) of liver cirrhosis (p=0.04) and INR (p=0.03). Conclusions. Concentrations of zinc and selenium in serum of patients with alcoholic liver cirrhosis are not independently related to concentrations of FGF-19 and ENG.
Dostawca treści:
Biblioteka Nauki
Artykuł

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