Search results for "PD"
showing 10 items of 1971 documents
Mathematical modelling and experimental study of straw co-firing with gas
2019
The main goal of the present study is to promote a more effective use of agriculture residues (straw) as an alternative renewable fuel for cleaner energy production with reduced greenhouse gas emissions. With the aim to improve the main combustion characteristics at thermo-chemical conversion of wheat straw, complex experimental study and mathematical modelling of the processes developing when co-firing wheat straw pellets with a gaseous fuel were carried out. The effect of co-firing on the main gasification and combustion characteristics was studied experimentally by varying the propane supply and additional heat input into the pilot device, along with the estimation of the effect of co-firing on…
Honeycomb supported Co3O4/CeO2 catalysts for CO/CH4 emissions abatement: effect of low Pd-Pt content on the catalytic activity
2007
Abstract A structured Co3O4–CeO2 composite oxide, containing 30% by weight of Co3O4, has been prepared over a cordieritic honeycomb support. The bimetallic, Pd–Pt catalyst has been obtained by impregnation of the supported Co3O4–CeO2 with Pd and Pt precursors in order to obtain a total metal loading of 50 g/ft3. CO, CH4 combined oxidation tests were performed over the catalyzed monoliths in realistic conditions, namely GHSV = 100,000 h−1 and reaction feed close to emission from bi-fuel vehicles. The Pd–Pt un-promoted Co3O4–CeO2 is promising for cold-start application, showing massive CO conversion below 100 °C, in lean condition. A strong enhancement of the CH4 oxidation activity, between 4…
The Partial Discharge Behavior of Different Materials under DC Periodic Stress
2019
The aim of the present work is to evaluate the PDs behavior by stressing a specimen with a new type of waveform named DCP. This waveform was proposed by the authors in a previous work with the aim to overcome the main issues of PDs under DC stress. In the previous work PDs test on Kapton specimen was performed. In this paper, we propose a new DCP test on a different insulating material, such as the XLPE. The obtained patterns and the acquired data have been evaluated in order to validate the DCP approach as a new method for PDs measure under constant stress. The behavior of the XLPE material has been reported and compared with the former measures obtained for Kapton material.
Formation and Growth of Pd Nanoparticles Inside a Highly Cross-Linked Polystyrene Support: Role of the Reducing Agent
2014
Simultaneous time-resolved SAXS and XANES techniques were employed to follow in situ the formation of Pd nanoparticles in a porous polystyrene support, using palladium acetate as a precursor and gaseous H2 or CO as reducing agents. These results, in conjunction with data obtained by diffuse reflectance UV–vis and DRIFT spectroscopy and TEM measurements, allowed unraveling of the different roles played by gaseous H2 and CO in the formation of the Pd nanoparticles. In particular, it was found that the reducing agent affects (i) the reduction rate (which is faster in the presence of CO) and (ii) the properties of the hosted nanoparticles, in terms of size (bigger with CO), morphology (spherica…
Compressibility and structural stability of ultra-incompressible bimetallic interstitial carbides and nitrides
2012
We have investigated by means of high-pressure x-ray diffraction the structural stability of Pd 2Mo 3N, Ni 2Mo 3C 0.52N 0.48, Co 3Mo 3C 0.62N 0.38, and Fe 3Mo 3C. We have found that they remain stable in their ambient-pressure cubic phase at least up to 48 GPa. All of them have a bulk modulus larger than 330 GPa, the least compressible material being Fe 3Mo 3C, B 0 = 374(3) GPa. In addition, apparently a reduction of compressibility is detected as the carbon content is increased. The equation of state for each material is determined. A comparison with other refractory materials indicates that interstitial nitrides and carbides behave as ultra-incompressible materials. © 2012 American Physic…
Synchrotron Radiation and Chemistry: Studies of Materials for Renewable Energy Sources
2014
We present an overview of selected applications of synchrotron radiation methods to topical chemical research. The analysis is limited to the studies on materials for renewable energy sources, focussing on topics peculiar to chemical research, such as reactivity and synthesis routes; in particular, the paper takes into account subjects having some relevance for the production and storage of energy based on hydrogen. Hydrogen production and storage are taken into account in the sections concerning: (i) Dye-sensitized solar cells, (ii) Metal-organic frameworks and (iii) Hydrides for hydrogen storage; production of energy by fuel cell devices is treated in (iv) Oxide ion and proton conductors …
MOF-Mediated Synthesis of Supported Fe-Doped Pd Nanoparticles under Mild Conditions for Magnetically Recoverable Catalysis**
2020
Metal–organic framework (MOF)-driven synthesis is considered as a promising alternative for the development of new catalytic materials with well-designed active sites. This synthetic approach is used here to gradually transform a new bimetallic MOF, with Pd and Fe as the metal components, by the in situ generation of aniline under mild conditions. This methodology results in a compositionally homogeneous nanocomposite formed by Fe-doped Pd nanoparticles that, in turn, are supported on iron oxide-doped carbon. The nanocomposite has been fully characterized by several techniques such as IR and Raman spectroscopy, TEM, XPS, and XAS. The performance of this nanocomposite as an heterogeneous cat…
Permanent magnetism in apoferritin-encapsulated Pd nanoparticles
2007
Pd nanoparticles have been prepared within the apoferritin cavity. X-Ray powder diffraction, transmission electronic microscopy and magnetization measurements have been used for characterizing the nanoparticles. The nanoparticles exhibit permanent magnetism at room temperature.
Structural and magnetic characterization of Pd nanoparticles encapsulated in apoferritin
2010
Pd nanoparticles exhibiting permanent magnetism at room temperature have been prepared within the apoferritin cavity. Pd nanoparticles in air and under an inert atmosphere were synthesized to study the influence of the aerobic and anaerobic conditions in the final magnetic properties. The surface of nanoparticles as well as the type of crystalline phase could determine the magnetic properties. X-ray powder diffraction, including Debye-function analysis, transmission electronic microscopy, and magnetization measurements have been used for characterizing the nanoparticles.
Physico-chemical characterization of Pd nanoparticles synthesized in w/o microemulsions
1998
Abstract The long time stability of surfactant-coated Pd nanoparticles in w/o microemulsions has been investigated. It has been proven that in suitable conditions, the use of the functionalized surfactant Pd(AOT)2 allows to obtain very stable nanosized Pd particles and to finely control their average size.