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1
Content available remote Determination of the best microstructure and titanium alloy powders properties using neural network
Duriagina Z. A., Tkachenko R. O., Trostianchyn A. M., Lemishka I. A., Kovalchuk A. M., Kulyk V. V., Kovbasyuk T. M.
Journal of Achievements in Materials and Manufacturing Engineering
|
2018
|
Vol. 87, nr 1
25--31
EN
Purpose: Create a software product using a probabilistic neural network (PNN) and database based on experimental research of titanium alloys to definition of the best microstructure and properties of aerospace components. Design/methodology/approach: The database creation process for artificial neural network training was preceded by the investigation of the granulometric composition of the titanium powder alloys, study of microstructure, phase composition and evaluation of micromechanical properties of these alloys by the method of material plasticity estimation in the conditions of hard pyramidal indenters application. A granulometric analysis was done using a special complex of materials science for the images analysis ImageJ. Metallographic investigations of the powder structure morphology were carried out on the scanning electron microscope EVO 40XVP. Specimens for micromechanical testing were obtained by overlaying the titanium alloy powders on the substrate made of the material close to chemical composition. Substrates were prepared by pressing the powder mixture under the load of 400 MPa and following sintering at 1300°C for 1 hour. Overlaying was performed by an electron gun ELA-6 (beam current – 16 mA). Findings: According to the modelling results, a threshold of the PNN accuracy was established to be over 80%. A high level of experimental data reproduction allows us a full or partial replacement of a number of experimental investigations by neural network modelling, noticeably decreasing, in this case, the cost of the material creation possessing the preset properties with preserved quality. It is expected that this software can be used for solving other problems in materials science too. Research limitations/implications: The accuracy of the PNN algorithm depends on the number of input parameters obtained experimentally and forms a database for the training of the system. For our case, the amount of input data is limited. Practical implications: Previously trained system based on the PNN algorithm will reduce the number of experiments that significantly reduce costs and time to study. Originality/value: A software product on the basis of the PNN network was developed. The training sample was built based on a series of laboratory studies granulometric composition of the titanium powder alloys, study of microstructure, phase composition and evaluation of micromechanical properties of powder materials. The proposed approach allows us to determine the best properties of the investigated material for the design of aerospace components.
2
Content available Research on stability of gomphrenin pigments influenced by Cu2+ ions
Szmyr N., Wybraniec S.
Challenges of Modern Technology
|
2017
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Vol. 8, no. 1
13--18
EN
This paper concerns the results of dehydrogenation of gomphrenin pigments isolated from the purple flowers of Gomphrena globosa L. depending on pH and Cu2+ activity. Betalains are the plant dyes divided into red-violet betacyanins and yellow-orange betaxanthins. These compounds show prohealth properties proven by numerous studies [1]. Isolation of gomphrenins from the plant material was performed in the following stages: preparative extraction, filtration on a silica layer, preliminary purification and concentration on a bed of strong anion exchanger, preparative chromatographic fractionation and sample liofilization. The dehydrogenation studies of gomphrenin I and II were carried out in aqueous solutions (pH 3, 5 and 7) catalyzed by Cu2+ ions addition. The resulting product mixtures of dehydrogenated and decarboxylated gomphrenin derivatives were monitored by high-performance liquid chromatography with diode-array and mass spectrometric detection (LC-DAD-ESI-MS). Based on the results, it can be stated that decarboxylated and dehydrogenated gomphrenin II derivatives are more stable than gomphrenin I derivatives, presumably due to acylation of the glucose moiety. The highest levels of gomphrenin I derivatives were observed at pH 7, however, they were mainly monodecarboxylated ones. At pH 3, significant fraction was represented by tridecarboxylated and dehydrogenated derivatives. The lowest yield of the degradation products was indicated at pH 5.
3
Content available Research on dehydrogenation of gomphrenin in heated ammonia solutions of organic solvents
Szmyr N., Wybraniec S.
Challenges of Modern Technology
|
2017
|
Vol. 8, no. 1
8--12
EN
In this report, the influence of ammonia on dehydrogenation of gomphrenin pigment, isolated from purple inflorescences of Gomphrena globosa L., in selected organic solvents (methanol, ethanol, acetone and acetonitrile) at 40°C is presented. Betacyanins are water-soluble, vacuolar plant pigments. Due to their numerous pro-health properties, they can be applied in the pharmaceutical industry and as food colorants. However, as most of natural products, they are less stable than synthetic dyes, therefore, further studies need to be carried out on their stability, but also on determination of their degradation products as well as degradation mechanisms. For the experiments of the ammonia treatment, prolonged isolation of gomphrenin from the plant material including extraction, preliminary purification, preparative HPLC fractionation, concentration and liofilization were performed. The tested pigment dissolved in organic solvents was treated by ammonia and the samples for analysis were taken during and after reaction. For identification of obtained derivatives of gomphrenin, high-performance liquid chromatography with diode-array and mass spectrometric detection (LC-DAD-ESI-MS) was performed. As a result of heat processing, the mixture of decarboxylated and dehydrogenated gomphrenin derivatives was detected. Based on the experimental results, it can be stated that gomphrenin is characterized by the greatest stability in methanolic solutions while it is the most labile in the acetonitrilic ones.
4
Content available remote Uporządkowane mezoporowate katalizatory CrOx/Al₂O₃ dla procesu odwodornienia propanu do propylenu
Węgrzyniak A., Węgrzynowicz A., Jarczewski S., Michorczyk B., Kuśtrowski P., Ogonowski J., Michorczyk P.
Przemysł Chemiczny
|
2016
|
T. 95, nr 10
1964--1968
PL
Poprzez replikację strukturalną otrzymano czysty i dotowany potasem mezoporowaty nośnik Al₂O₃. Na bazie przygotowanych nośników metodą impregnacji zsyntetyzowano katalizatory chromowe zawierające 20% mas. Cr₂O₃. Otrzymane preparaty przetestowano pod kątem aktywności katalitycznej w procesie odwodornienia propanu do propylenu. Zbadano wpływ metody preparatyki nośnika oraz dotowania potasem na właściwości katalityczne. Określono również wpływ temperatury reakcji na szybkość dezaktywacji.
EN
Samples of pure and K-doped mesoporous Al₂O₃ were prepd. from aq. soln. of Al(NO₃)₃ by nanoreplication method and used for prodn. of Cr₂O₃-contg. catalysts (20% by mass) by the incipient wetness technique. The catalysts were tested in the dehydrogenation of PrH to propene. Both support synthesis method and K-doping effected the performance of the catalysts. The deactivation of the catalyst was also studied at various reaction temps.
5
Content available remote Odwodornienie cykloheksanolu do cykloheksanonu na katalizatorze Zn/Fe
Zimowski A., Zylbersztejn M., Sylwestrowicz R.
Przemysł Chemiczny
|
2015
|
T. 94, nr 5
736-740
PL
Zbadano wpływ obciążenia katalizatora Zn/Fe w zakresie 0,37–0,70 h-1 na selektywność reakcji odwodornienia cykloheksanolu. Zbadano również wpływ stopnia konwersji cykloheksanolu do cykloheksanonu na selektywność reakcji odwodornienia cykloheksanolu. W tym celu porównano selektywność reakcji odwodornienia cykloheksanolu przy konwersji 56 i 76% i obciążeniu katalizatora 0,6 h-1. Wzrost obciążenia katalizatora i obniżenie stopnia konwersji cykloheksanolu pociągnął za sobą wzrost selektywności reakcji. Obniżenie stopnia konwersji cykloheksanolu w znaczący sposób wydłużyło okresy pracy katalizatora między regeneracjami.
EN
Effect of Zn/Fe catalyst load (0.37–0.70 h-1) and cyclohexanol dehydrogenation degree (56 and 76%) on the reaction selectivity was studied under industrial plant conditions. An increase in catalyst load and a decrease in cyclohexanol conversion degree resulted in an increase in reaction selectivity. The decreasing the cyclohexanol conversion degree resulted also in increasing the catalyst life time.
6
Content available remote Właściwości katalityczne Cr/SBA-1 w procesie odwodornienia propanu do propenu w obecności CO2 – wpływ tekstury i powierzchni właściwej nośnika
Niemczyk-Wrzeszcz M., Michorczyk P.
Czasopismo Techniczne. Chemia
|
2012
|
R. 109, z. 1-Ch
109--118
PL
Na bazie materiałów SBA-1 otrzymano serie katalizatorów chromowych zawierających 5% mas. Cr. Katalizatory scharakteryzowano różnymi metodami fizykochemicznymi. Aktywność katalityczną układów zbadano w procesie odwodornienia propanu do propenu w obecności CO2. Badania wykazały, że aktywność badanych katalizatorów rośnie ze wzrostem powierzchni właściwej nośnika SBA-1. Z kolei tekstura ma niewielki wpływ na właściwości katalityczne (objętość porów i ich średni wymiar).
EN
On the basis of the SBA-1 materials, series of chromium catalysts containing 5wt% Cr were obtained. The catalysts were characterized by various physicochemical techniques. The catalytic performance was investigated in the dehydrogenation of propane process in the presence of CO2. Studies have shown that the catalytic activity increases with the increase of specific surface area of support. The total pore volume and pore size (texture) of the support have insignificant influence on the catalytic properties.
7
Content available remote Badanie aktywności MoO3 naniesionego na SBA-15 i Al-SBA-15 w procesie odwodornienia propanu do propenu w obecności CO2
Zeńczak K., Michorczyk P., Rachwalik R., Ogonowski J.
Czasopismo Techniczne. Chemia
|
2010
|
R. 107, z. 1-Ch
353-360
PL
Otrzymano serię katalizatorów molibdenowych zawierających 10% mas. MoO3 osadzonego na SBA-15 i jej modyfikację zawierającą glin wprowadzony metodą po syntezową (Al-SBA-15). Wyjściowy nośnik oraz katalizatory scharakteryzowano różnymi metodami fizykochemicznymi. Aktywność układów katalitycznych zbadano w procesie odwodornienia propanu do propenu w obecności CO2. Ustalono, że wprowadzenie glinu do matrycy SBA-15 wpływa na zwiększenie aktywności katalitycznej oraz selektywności do propenu.
EN
The catalysts containing 10 wt % of MoO3 supported on SBA-15 and their modification with aluminium (Al-SBA-15) were prepared. The support and catalysts were characterized by various physicochemical techniques. The catalytic activity was investigated in the dehydrogenation of propane with carbon dioxide. It was found that the incorporation of aluminum into SBA -15 enhances the catalytic activity and selectivity to propene.
8
Surface Structure and Catalytic Properties of Cu/SiO2 Catalysts Prepared by Different Methods
Ji D. H., Zou X. J., Zheng D. F., Wang L. X., Liu S. Y., Zhu W. C., Wang G. J., Wang Z. L.
Polish Journal of Chemistry
|
2008
|
Vol. 82, nr 5
1097-1104
EN
The silica supported copper catalysts were prepared via impregnation (IM), solgel (SG) and deposition precipitation (DP) methods. The catalysts were characterized by XRD, H2-TPR, NH3-TPD, H2-N2O titration, XPS, BET and EPR techniques. The results indicated that two copper species, Cu2+ and Cu0 exist on the surface of SG catalyst; how ever, only Cu0 species could be found on the surface of reduced IM and DP catalysts, and the dispersion of Cu0 on IM catalyst was better than that on DP catalyst. According to the reaction results, Cu0 should be the active sites for dehydrogenation of cyclohexanol. Cu2+ species on the surface of SG catalyst might be responsible for the dehydration of cyclohexanol. The residual Na was found on the surface of DP catalyst, which made the acidity decreas ing, and the Cu crystallite growing up easily.
9
Content available remote Odwodornienie izobutanu do izobutenu w obecności ditlenku węgla na katalizatorze wanadowym naniesionym na węgiel aktywny
Ogonowski J., Skrzyńska E.
Czasopismo Techniczne. Chemia
|
2007
|
R. 104, z. 1-Ch
117-121
PL
W niniejszym artykule przedstawiono badania dotyczące aktywności katalizatora wanadowego naniesionego na powierzchnię węgla aktywnego w reakcji odwodornienia izobutanu do izobutenu w obecności ditlenku węgla oraz w atmosferze gazu inertnego. Wyniki porównano z rezultatami reakcji Boudouarda oraz gazu wodnego, co pozwoliło stwierdzić, że badany proces przebiega zgodnie z modelem dwustopniowym.
EN
The activity of the vanadium oxide supported on active carbon catalyst was tested in the reaction of isobutane dehydrogenation reaction in the presence and absence of carbon dioxide. The data were compared with the results obtained in the Boudouard and reverse water gas shift reactions. It has been found that isobutane dehydrogenation process proceeds via two-step reaction pathway.
10
Synthesis of 23-Oxa-22-deoxo Analogues of OSW-1 Aglycone
Kruszewska A., Wilczewska A., Wojtkiewicz A., Morzycki J.
Polish Journal of Chemistry
|
2006
|
Vol. 80, nr 4
611-615
EN
Four ether analogues of OSW-1 aglycone were obtained by alkylation of a steroid alcohol with alkyl bromide. During theWilliamson reaction promoted by sodium hydride in addition to alkylation, an unusual dehydrogenation of secondary alcohol was observed.
11
Content available Radiation chemistry of radioactive waste to be stored in the salt mine repository
Zagórski Z.
Nukleonika
|
2006
|
Vol. 51,suppl.2
87-92
EN
Different aspects of radiation chemistry connected with long storage of radioactive waste are discussed. More details are given on the dehydrogenation of organic, and in particular polymeric waste, contaminated with transuranium nuclides. Determinations of radiation yields of hydrogen from typical waste were made, indicating limits of safe activities tolerable. No danger of chain reactions of hydrogen release was detected.
12
Content available remote Odwodornienie izobutanu w obecności ditlenku węgla - analiza termodynamiczna procesu
Ogonowski J., Sikora E., Skrzyńska E.
Nafta-Gaz
|
2005
|
R. 61, nr 3
120-124
PL
W pracy przeprowadzono analizę termodynamiczną procesu odwodornienia izobutanu w obecności CO2 dla modelu stechiometrycznego obejmującego sześć reakcji liniowo niezależnych: reakcję odwodornienia izobutanu do izobutenu, reakcję gazu wodnego oraz reakcje termicznego krakingu izobutanu do niższych węglowodorów.
EN
In the work thermodynamic consideration of dehydrogenation of isobutane to isobutene in the presence of carbon dioxide was performed. Stoichiometric model established six linear independent reactions: dehydrogenation isobutane to isobutene, reverse water gas shift reactions and thermal cracking reactions of isobutane to light hydrocarbons.
13
Effect of Residual Na on Cu--ZnO Catalyst in Dehydrogenation of 2-Butanol
Wang Z., Wang G., Zhu W., Yang P., Ma H., Liu G., Qu Y., Yu X.
Polish Journal of Chemistry
|
2004
|
Vol. 78 / nr 6
861-868
EN
A series of residual Na on Cu-ZnO catalysts were prepared by co-precipitation method. The effect of residual Na on catalysts was examined in dehydrogenation of 2-butanol. The catalysts were characterized by BET, ICP, XRD, TPR and XPS techniques. The TPR result showed that residual Na made CuO exists in different phases, the higher the content of Na the harder the reduction of CuO. For reduced or used catalyst with a high content of Na, the XPS result indicated that Na diffused to the catalyst surface and inhibited the interaction between Cu and ZnO. The sharp decrease in catalytic activity by Na incorporation could be interpreted mainly in terms of the copper particle size increasing during reaction. Interaction between Cu and ZnO could have stabilized the copper species. The Na free catalyst shows high and stable activity in dehydrogenation of 2-butanol.
14
Content available remote Analiza termodynamiczna reakcji konwersji izobutanu do izobutenu w obecności ditlenku węgla
Ogonowski J., Skrzyńska E., Sikora E.
Czasopismo Techniczne. Chemia
|
2004
|
R. 101, z. 1-Ch
121-126
PL
Przeprowadzono analizę termodynamiczną reakcji konwersji izobutanu do izobutenu w obecności CO2. Wykazano korzystny wpływ obecności CO2 na przebieg badanej reakcji.
EN
Thermodynamic consideration of the dehydrogenation of isobutane to isobutene shows that the equilibrium conversion of isobutane dehydrogenation to isobutene in the presence of carbon dioxide is much higher than that for the dehydrogenation in the steam presence.
15
Content available remote Wpływ preparatyki tlenkowych katalizatorów chromowych na przebieg odwodornienia propanu do propenu w obecności ditlenku węgla
Michorczyk P., Ogonowski J.
Przemysł Chemiczny
|
2003
|
T. 82, nr 6
402-405
16
Hydroperoxide Oxidation of Benzylamines Catalyzed by Selenium Compounds
Brząszcz M., Kloc K., Młochowski J.
Polish Journal of Chemistry
|
2003
|
Vol. 77 / nr 11
1579-1586
EN
Selenium(IV) oxide, poly(bis-1,2-phenylene) diselenide, bis[2-(N-benzisoselenazol- 3(2H)-onyl]diselenide and particularly 2-phenyl-1,2-benzisoselenazol-3(2H)-one (ebselen), were employed as the catalysts for hydrogen peroxide and t-butyl hydroperoxide oxidation of benzylamines. A reaction of primary amines proceeded via hydroxylamine and oxime, and the nitriles accompanied by imines, carboxylic acids and aldehydes were the final products. The secondary amines produced mainly the nitrones, while tetrahydroisoquinoline was dehydrogenated to isoquinoline.
17
Dehydrogenation of Isobutane to Isobutene over V2O5/gamma-Al2O3 Catalysts: Effects of the Extent of Catalyst Reduction on Catalytic Performance
Ma H., Fu Y.-H., Li Y., Wang Z. -L., Zhu W. -C., Wang G.-J.
Polish Journal of Chemistry
|
2003
|
Vol. 77 / nr 7
903-908
EN
V2O5/_-Al2O3 catalysts for the dehydrogenation of isobutane to isobutene were prepared by impregnation and characterized by BET,H2-TPR, ESR and XPS. Based on our studies of the effects of the extent of catalyst reduction on catalytic performance, we conclude that the V2O5/_-Al2O3 catalytic activity for the dehydrogenation of isobutane is related to the valence state of vanadium present in the catalyst, in the order of V4+> V3+. Furthermore, V4+ species are the main active sites of this reaction under the present reaction conditions.
18
Catalytic Performance of CuO/ZnAl2O4-Al2O3 Catalysts in n-Hexanol Conversion
Grabowska H., Zawadzki M., Wrzyszcz J.
Polish Journal of Chemistry
|
2003
|
Vol. 77 / nr 5
779-787
EN
Aseries of CuO/ZnAl2O4-Al2O3 catalysts with various CuO loading were prepared by an impregnation method. The effect of copper oxide addition for the reaction of n-hexanol was examined. The reactions were carried out at atmospheric pressure in a fixed bed reactor in the temperature range of 533-663 K. Experimental data show that the addition of copper oxide into studied catalysts does improve the activity in dehydrogenation of alcohol. Catalysts containing CuO have both dehydration and dehydrogenation properties, whereas ZnAl2O4-Al2O3 carrier only dehydrates alcohol. Obtained results indicate that the dehydrogenation of n-hexanol over CuO/ZnAl2O4-Al2O3 catalysts proceeds via carboxy intermediate.
19
Hydrothermal preparation and catalytic activity of copper oxide supported on zinc aluminate spinel.
Zawadzki M., Grabowska H., Miśta W.
Prace Naukowe Instytutu Chemii i Technologii Nafty i Węgla Politechniki Wrocławskiej. Konferencje
|
2002
|
Vol. 10, nr 57
401-406
EN
Copper oxide supported on ZnAl2O4 catalysts with various CuO loading were prepared by wet impregnation method. The effect of copper oxide addition on catalytic performance of ZnAl2O4 in n-hexanol reactions was examined. Experimental data show that the addition of CuO into studied catalysts does improve the activity in dehydrogenation of alcohol. Catalysts containing CuO have mainly dehydrogenation properties whereas ZnAl2O4 carrier dehydrates and dehydrogenates alcohol.
20
Effect of Potassium Modification of Structure and Reactivity of V2O5/gamma-Al2O3 for Isobutane Dehydrogenation to Isobutene
Ma H., Wang Z. -L., Zhu W. -C., Jing S. -B., Ji D. -H., Wang G.-J.
Polish Journal of Chemistry
|
2002
|
Vol. 76 / nr 12
1733-1738
EN
Undoped and K-doped V2O5/ -Al2O3 catalysts for the dehydrogenation of isobutane to isobutene were prepared by impregnation and characterized by means of BET, H2-TPR, NH3-TPD, XPS and ESR. It is found that potassium addition changes acidic and electric properties of V2O5/ -Al2O3 and results in a better spreading of V2O5 over -Al2O3 surface. Small addition of potassium toV2O5/ -Al2O3 catalyst (K:V = 0.05), consisting of 12 wt% V2O5, increased the activity and selectivity in dehydrogenation of isobutane to isobutene.
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