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| 2. |
- Gergely, Andras, et al.
(författare)
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Hydrogen Sulfide Corrosion of Carbon and Stainless Steel Alloys in Mixtures of Renewable Fuel Sources under Co-Processing Conditions
- 2018
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Ingår i: Modern Applied Science. - : Canadian Center of Science and Education. - 1913-1844 .- 1913-1852. ; 12:4, s. 227-255
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Tidskriftsartikel (refereegranskat)abstract
- Corrosion rates of steel alloys were investigated in gas oil and its mixture with waste cooking oil and animal waste lard over 1, 3, 7 and 21 days under desulfurizing condition. Co-processing conditions were attempted to simulate by batch-reactor experiment at temperatures between 200 and 300oC and pressures between 20 and 90 bar in the presence of 2 volume% hydrogen sulfide. Integral and differential corrosion rates were defined by weight losses. Intense sulfide corrosion of carbon steels was less impacted by the biomass sources. Thinner scales in gas oil was probably due to frequent cohesive failure, whereas thicker layers in biomass mixtures were allowed to form to afford limited physical protection. The high corrosion rate of low alloy steel with temperature over time is related to inefficient protection by the metal sulfide scales. Greater activation energy and enthalpy balance in the formation of activated complex is expected to reflect in thick cohesive scales. Loose layers and the less unfavorable entropy balance in the transition state did not lead to valuable barrier protection. High sulfide corrosion resistance of stainless steels is in chemical in nature markedly impacted by the biomass fuel sources and contributed especially by the acidic species. Corrosion rates increased with temperature by magnitude similar to those of carbon steels, which probably owes to the less unfavorable entropy and free energy balance between the initial and transition states of the reactants.
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| 3. |
- Dévai, Gergely, et al.
(författare)
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Efficient Code Generation from the High-level Domain-specific Language Feldspar for DSPs
- 2010
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Ingår i: ODES-8: 8th Workshop on Optimizations for DSP and Embedded Systems, workshop associated with IEEE/ACM International Symposium on Code Generation and Optimization (CGO).
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Konferensbidrag (refereegranskat)abstract
- Software for digital signal processors (DSPs) is traditionally highly hardware-dependent and hence porting it to new processors usually requires significant design effort. In this paper we present Feldspar (Functional Embedded Language for DSP and Parallelism), an embedded, high-level, domain-specific language for DSP algorithm design and the compilation techniques we developed for generating C code from specifications written in Feldspar. While Feldspar allows description of algorithms on specification level, we show that with the right set of abstractions and transformations this high level, functional specification can be transformed into C code that is comparable or better than reference, hand-crafted C language implementations. The Feldspar compiler is highly modular and plugin-based, hence future hardware-specific plugins will enable automatic generation of efficient, hardware-specific code. This approach enables the encapsulation of knowledge of hardware completely in the compiler and thus allows description of algorithms in completely hardware-independent, portable manner.
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| 4. |
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| 5. |
- Halonen, Niina, et al.
(författare)
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Low-temperature growth of multi-walled carbon nanotubes by thermal CVD
- 2011
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Ingår i: Physica status solidi. B, Basic research. - Malden : Wiley-Blackwell. - 0370-1972 .- 1521-3951. ; 248:11, s. 2500-2503
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Tidskriftsartikel (refereegranskat)abstract
- Low-temperature thermal chemical vapor deposition (thermal CVD) synthesis of multi-walled carbon nanotubes (MWCNTs) was studied using a large variety of different precursor compounds. Cyclopentene oxide, tetrahydrofuran, methanol, and xylene: methanol mixture as oxygen containing heteroatomic precursors, while xylene and acetylene as conventional hydrocarbon feedstocks were applied in the experiments. The catalytic activity of Co, Fe, Ni, and their bi-as well as tri-metallic combinations were tested for the reactions. Low-temperature CNT growth occurred at 400 degrees C when using bi-metallic Co-Fe and tri-metallic Ni-Co-Fe catalyst (on alumina) and methanol or acetylene as precursors. In the case of monometallic catalyst nanoparticles, only Co (both on alumina and on silica) was found to be active in the low temperature growth (below 500 degrees C) from oxygenates such as cyclopentene oxide and methanol. The structure and composition of the achieved MWCNTs products were studied by scanning and transmission electron microscopy (SEM and TEM) as well as by Raman and X-ray photoelectron spectroscopy (XPS) and by X-ray diffraction (XRD). The successful MWCNT growth below 500 degrees C is promising from the point of view of integrating MWCNT materials into existing IC fabrication technologies. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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