Browsing by Subject "Reduction"

Conference Object

Bond graph based modal decomposition of systems with non-proportional damping

Louca, Loucas S. (Affiliation: Department of Mechanical and Manufacturing Engineering, University of Cyprus, 75 Kallipoleos Street, Nicosia 1678, CyprusCorrespondence Address: Louca, L.S.Department of Mechanical and Manufacturing Engineering, University of Cyprus, 75 Kallipoleos Street, Nicosia 1678, Cyprusemail: lslouca@ucy.ac.cy, 2012)

Modal analysis of lumped parameter and continuous dynamic linear systems is extensively used to study their dynamic behavior and controller design. In both cases, a reduction of the model size that does not degrade accuracy ...

Article

Catalytic behavior of La-Sr-Ce-Fe-O mixed oxidic/perovskitic systems for the NO+CO and NO+CH4+O2 (lean-NOx) reactions

Belessi, Vassiliki C.; Costa, Costas N.; Bakas, Thomas V.; Anastasiadou, T.; Pomonis, Phillippos J.; Efstathiou, Angelos M. (2000)

Mixed oxides of the general formula La0.5SrxCeyFeOz were prepared by using the nitrate method and characterized by XRD and Mossbauer techniques. The crystal phases detected were perovskites LaFeO3 and SrFeO3-x and oxides ...

Article

Catalytic removal of nitrates from waters

Constantinou, C. L.; Costa, Costas N.; Efstathiou, Angelos M. (2010)

The selective catalytic reduction of nitrates (NO3 -) in pure water towards N2 formation by the use of gaseous H2 and in the presence of O2 (air) at 1 atm total pressure and 25 °C has been investigated over Pd-Cu supported ...

Article

Comparative study of La-Sr-Fe-O perovskite-type oxides prepared by ceramic and surfactant methods over the CH4 and H2 lean-deNOx

Stathopoulos, Vassilis N.; Belessi, Vassiliki C.; Bakas, Thomas V.; Neophytides, Stylianos G.; Costa, Costas N.; Pomonis, Phillippos J.; Efstathiou, Angelos M. (2009)

Mixed oxides of the general formula La0.8Sr0.2FeO3-x were prepared by ceramic and surfactant methods and tested towards the NO/H2/O2 and NO/CH4/O2 lean-deNOx reactions in the 200-450 °C range. The materials were characterized ...

Article

Deactivation of Pd/Ce 0.5Zr 0.5O 2 model three-way catalyst by P, Ca and Zn deposition

Christou, Stavroula Y.; García-Rodríguez, S.; Fierro, José Luis García; Efstathiou, Angelos M. (2012)

The negative effects of P, P-Ca and P-Zn deposition on the surface of a model 1wt% Pd/Ce 0.5Zr 0.5O 2 " three-way" catalyst (TWC) on its structural, morphological, textural, oxygen storage and release, and catalytic ...

Article

Detection of the His-heme Fe2+-NO species in the reduction of NO to N2O by ba3-oxidase from thermus thermophilus

Pinakoulaki, Eftychia; Ohta, T.; Soulimane, T.; Kitagawa, T.; Varotsis, Constantinos (2005)

Reaction pathways in the enzymatic formation and cleavage of the N-N and N-O bonds, respectively, are difficult to verify without the structure of the intermediates, but we now have such information on the heme a3 2+-NO ...

Article

Direct detection of Fe(IV)=O intermediates in the cytochrome aa3 oxidase from Paracoccus denitrificans[H2O2 reaction

Pinakoulaki, Eftychia; Pfitzner, U.; Ludwig, B.; Varotsis, Constantinos (2003)

We report the first evidence for the formation of the "607- and 580-nm forms" in the cytochrome oxidase aa3/H2O2 reaction without the involvement of tyrosine 280. The pKa of the 607-580-nm transition is 7.5. The 607-nm ...

Article

The effects of the use of weak organic acids on the improvement of oxygen storage and release properties of aged commercial three-way catalysts

Lambrou, Panayiota S.; Christou, Stavroula Y.; Fotopoulos, Apostolos P.; Foti, F. K.; Angelidis, Thomas N.; Efstathiou, Angelos M. (2005)

The efficiency of weak organic acid solutions for improving the oxygen storage and release properties of aged commercial three-way catalysts (TWC) has been investigated. For the first time, three candidate leaching solutions, ...

Article

Enhancing the nanoscratch resistance of pulsed laser deposited DLC films through molybdenum-doping

Constantinou, M.; Pervolaraki, M.; Koutsokeras, L.; Prouskas, C.; Patsalas, P.; Kelires, P.; Giapintzakis, John; Constantinides, G. (2017)

Pulsed laser deposition was used to grow DLC and molybdenum-doped DLC (DLC:Mo) films, with metal contents up to 3.2 at.%, on silicon substrates. The microstructural details of the films were investigated using X-ray ...

Article

Fourier transform infrared evidence for a ferric six-coordinate nitrosylheme b3 complex of cytochrome cbb3 oxidase from Pseudomonas stutzeri at ambient temperature

Stavrakis, Stavros; Pinakoulaki, Eftychia; Urbani, A.; Varotsis, Constantinos (2002)

We report the first vibrational study of NO bound to an oxidized heme-copper oxidase. Cytochrome cbb3 oxidase from P. stutzeri reduces both O2 and NO to H2O and N2O, respectively. The ferric nitrosyl complex of cbb3 exhibits ...

Article

Gold colloids from cationic surfactant solutions. 1. Mechanisms that control particle morphology

Leontidis, Epameinondas; Kleitou, K.; Kyprianidou-Leodidou, Tasoula; Bekiari, Vlasoula; Lianos, P. (2002)

The mechanism of formation of gold particles by reduction of AuIII in solutions of alcyltrimethylammonium chloride surfactants was studied in the absence and in the presence of NaCl. AuIII anions interact strongly with ...

Article

Industrial H2-SCR of NO on a novel Pt/MgO-CeO2 catalyst

Costa, Costas N.; Savva, Petros G.; Fierro, José Luis García; Efstathiou, Angelos M. (2007)

We describe here the performance of a novel MgO-CeO2-supported Pt (0.1 wt%) catalyst towards the selective conversion of NO into N2 (SN2 > 80%) by using H2 (H2-SCR) under process conditions similar to those encountered in ...

Article

Modal analysis reduction of multi-body systems with generic damping

Louca, Loucas S. (2014)

Modal analysis of multi-body systems is broadly used to study the behavior and controller design of dynamic systems. In both cases, model reduction that does not degrade accuracy is necessary for the efficient use of these ...

Conference Object

Modal analysis reduction of multi-body systems with generic damping

Louca, Loucas S. (Caltek s.r.l., 2012)

Modal analysis of multi-body systems is broadly used to study the behavior and controller design of dynamic systems. In both cases, model reduction that does not degrade accuracy is necessary for the efficient use of these ...

Article

Modelling and reduction techniques for studies of integrated hybrid vehicle systems

Louca, Loucas S.; Yildir, B. U. (2006)

Models of integrated vehicle systems are essential for designing hybrid vehicles by means of simulation-based optimization. Given the complexity of hybrid vehicle systems, designing is a time consuming process that requires ...

Article

Oxy-chlorination as an effective treatment of aged Pd/CeO 2-Al 2O 3 catalysts for Pd redispersion

Lambrou, Panayiota S.; Polychronopoulou, Kyriaki; Petallidou, Klito C.; Efstathiou, Angelos M. (2012)

The present work reports on the effects of oxy-chlorine gas treatment (use of Cl 2/O 2/He gas mixture) applied on a 5wt% Pd/20wt% CeO 2-Al 2O 3 catalyst towards Pd redispersion. X-ray diffraction (XRD), X-ray photoelectron ...

Article

Power conserving bond graph based modal representations and model reduction of lumped parameter systems

Louca, Loucas S. (2014)

Dynamic analysis is extensively used to study the behavior of continuous and lumped parameter linear systems. In addition to the physical space, analyses can also be performed in the modal space where very useful frequency ...

Article

The remarkable effect of oxygen on the N2 selectivity of water catalytic denitrification by hydrogen

Constantinou, C. L.; Costa, Costas N.; Efstathiou, Angelos M. (2007)

The selective catalytic reduction of nitrates (NO3-) in pure water toward N2 formation by the use of gaseous H2 and in the presence of O2 (air) at 1 atm total pressure and 25°C has been investigated over Pd-Cu supported ...

Article

Selective catalytic reduction of NO by H2/C3H6 over Pt/Ce1-xZrxO2-Δ: The synergy effect studied by transient techniques

Kalamaras, Christos M.; Olympiou, G. G.; Pârvulescu, V. I.; Cojocaru, B.; Efstathiou, Angelos M. (2017)

A series of Pt/CexZr1-xO2-δ(x = 0.4–0.6) solids were synthesized and evaluated for the SCR of NO under lean burn conditions (2.5 vol% O2) using C3H6and H2as reducing agents. SSITKA-Mass Spectrometry, SSITKA-DRIFTS and other ...

Article

Synergistic effects of crystal phases and mixed valences in La-Sr-Ce-Fe-O mixed oxidic/perovskitic solids on their catalytic activity for the NO+CO reaction

Belessi, Vassiliki C.; Bakas, Thomas V.; Costa, Costas N.; Efstathiou, Angelos M.; Pomonis, Phillippos J. (2000)

Mixed oxidic and perovskite-type materials based on the La, Sr, Ce and Fe elements were prepared using a mixture of nitrates salts and heating at 1000°C. Three groups of solids were synthesized: (i) La(1-y)Ce(y)FeO3 (y=0.2, ...