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132 results on '"Petrov, Lachezar"'

4. Critical Information Infrastructure Protection Model and Methodology, Based on National and NATO Study

Author

Petrov, Lachezar, Stoianov, Nikolai, Tagarev, Todor, Kacprzyk, Janusz, Series editor, Pal, Nikhil R., Advisory editor, Bello Perez, Rafael, Advisory editor, Corchado, Emilio S., Advisory editor, Hagras, Hani, Advisory editor, Kóczy, László T., Advisory editor, Kreinovich, Vladik, Advisory editor, Lin, Chin-Teng, Advisory editor, Lu, Jie, Advisory editor, Melin, Patricia, Advisory editor, Nedjah, Nadia, Advisory editor, Nguyen, Ngoc Thanh, Advisory editor, Wang, Jun, Advisory editor, Zamojski, Wojciech, editor, Mazurkiewicz, Jacek, editor, Sugier, Jarosław, editor, and Walkowiak, Tomasz, editor

Published
2018
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39. Surface behavior of alumina-supported Pt catalysts modified with cerium as revealed by X-ray diffraction, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy of CO adsorption

Author

Riguetto, Benecildo A., Damyanova, Sonia, Gouliev, Gias, Marques, Clelia M.P., Petrov, Lachezar, and Bueno, Jose Maria C.

Subjects
Carbon compounds -- Properties, Carbon compounds -- Research, Photoelectron spectroscopy -- Research, Cerium -- Research, Chemicals, plastics and rubber industries
Abstract

The spectral characterization of Pt supported on Al2O3, CeO2, and mixed CeO2-Al2O3 oxides with different CeO2 loadings shows the great influence of the type of the support and pretreatment temperature on the surface state of Pt and Ce. The results obtained by applying the X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR) spectroscopy of CO adsorption to the samples is presented.

Published
2004

40. Catalytic hydrolysis of sodium borohydride on Co catalysts

Author

Inokawa, Hitoshi, primary, Driss, Hafedh, additional, Trovela, Florencio, additional, Miyaoka, Hiroki, additional, Ichikawa, Takayuki, additional, Kojima, Yoshitsugu, additional, Zaman, Sharif F., additional, Al-Zahrani, Abdulrahim, additional, Alhamed, Yahia, additional, and Petrov, Lachezar, additional

Published
2016
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45. Influence of alkali metal (Li and Cs) addition to Mo2N catalyst for CO hydrogenation to hydrocarbons and oxygenates.

Author

Zaman, Sharif F., Pasupulety, Nagaraju, Al‐Zahrani, Abdulrahim A., Daous, Muhammad A., Driss, Hafedh, Al‐Shahrani, Saad S., and Petrov, Lachezar

Subjects
ALKALI metals, HYDROCARBONS, HYDROGENATION
Abstract

Abstract: The aim of this work is to understand the catalytic behaviour of Li and Cs promoted Mo2N for CO hydrogenation to hydrocarbons and oxygenates at the reaction conditions 275–325 °C, 7 MPa, and 30 000 h−1 GHSV. Molybdenum nitrides were synthesized via temperature programmed treatment of ammonium heptamolybdate (AHM) and alkali metal (AM) precursors under continuous gaseous ammonia flow. Unpromoted Mo2N and AM‐Mo2N catalysts were characterized using BET‐pore size, X‐ray diffraction, TPD‐mass of CO, HR‐TEM, and XPS techniques. Nominal loadings of 1, 5, and 10 wt% of Li and Cs were selected for these studies. At a 10 % CO conversion level, the total oxygenate selectivity of 28, 11, and 6.5 % was observed on 5Cs‐Mo2N, 5Li‐Mo2N, and unpromoted Mo2N, respectively. The decreased oxygenate selectivity for unpromoted Mo2N was mainly associated with CO dissociative hydrogenation on Moδ+ sites. On the other hand, improved molecular CO insertion into −CxHy intermediate accelerates the total oxygenate formation on the Cs‐Mo‐N catalyst. However, during nitridation, crystal structure changes were observed in Li‐Mo‐N and the obtained oxygenates selectivity was attributed to the Li2MoO4 phases. At lower AM loadings, the active sites corresponding to oxygenates formation were inadequate, and at higher AM loadings, surface metallic molybdenum decreased the total oxygenate selectivity. [ABSTRACT FROM AUTHOR]

Published
2018
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49. Mechanical and corrosion behavior of amorphous and crystalline electroless Ni-W-P coatings

Author

Alzahrani, Abdulrahim, Alhamed, Yahia, Petrov, Lachezar Angelov, Armyanov, Stephan Atanassov, Valova, Eugenia, Georgieva, Jenia, Dille, Jean, Alzahrani, Abdulrahim, Alhamed, Yahia, Petrov, Lachezar Angelov, Armyanov, Stephan Atanassov, Valova, Eugenia, Georgieva, Jenia, and Dille, Jean

Abstract

Two types of electroless Ni-W-P coatings: nanocrystalline with low P and amorphous with higher P content are investigated. Scanning probe microscopy is applied to study their morphology. Textured nanocrystalline coatings consist of coarse pyramids built of nanometer thick lamellas. The surface morphology of amorphous coatings is much finer and uniform. Nanohardness of all coatings depends on W content. Microhardness is increasing during the heat treatment up to 350 °C due to nickel phosphide precipitation affected by tungsten also. The wear resistance of nanocrystalline Ni-W-P coatings is much higher than that of amorphous in spite of the similar tungsten content in both. Lower corrosion resistance of amorphous Ni-W-P coatings is found by weight loss method during long-term immersion in 5 % NaCl. Electrochemical tests by potentiodynamic polarization curves in two model corrosion media - solutions of 0.5 M H 2SO4 and 5 % NaCl - are performed. The corrosion of bi-layered Ni-W-P/Ni-P and Ni-W-P/Ni-Cu-P deposits on mild steel is also investigated. The results prove that an electroless Ni-W-P coating on mild steel extremely improves its mechanical and corrosion behavior. It is demonstrated that in addition to deposit's structure and composition, the distribution and chemical state of alloy ingredients are also responsible for its properties. © 2014 Springer-Verlag Berlin Heidelberg., SCOPUS: ar.j, info:eu-repo/semantics/published

Published
2014

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