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Sulphur poisoning and rigeneration of Pd/Al2O3 and Pd/CeO2-Al2O3 catalysts for combustion of methane
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Influence of solfonated melamine formaldehyde condensate on the quality of building blocks production by extrusion of cement-clay pastes
No full textSulphur poisoning and regeneration of Pd-Al2O3 and Pd-Al2O3-CeO2 catalyst for the combustion of methane
No full textPredicting developmental language disorders using artificial intelligence and a speech data analysis tool
No full textDevelopmental Language Disorder (DLD) affects children's comprehension and production of spoken language without any known biomedical condition. The importance of early identification of DLD is widely acknowledged. Several studies have explored DLD predictors to identify children needing further diagnostic investigation. Most of these measures might be problematic for young children and bilingual children. Based on literature reporting fragile rhythmic abilities in children with DLD, in our study, we followed a different approach. We explored how non-linguistic measures of rhythmic anticipation can be gathered by means of advanced information technology and used to identify children at risk of DLD. With this aim, we developed MARS, a web-based tool to collect such data in a playful way and to analyze them using Machine Learning. MARS engages children in rhythmic babbling exercises, records their vocal productions, and analyzes the recordings. We discuss the methodological rationale of MARS and its underlying technology, and we describe a preliminary study with N = 47 children with and without DLD. The analysis of the audio features of participants' rhythmic vocal productions highlights different patterns in the two groups. This result, although preliminary, suggests that MARS could be a valuable tool for early DLD assessment
Morphosyntax and logical abilities in Italian poor readers: The problem of SLI under-identification
No full textThe study investigated morphosyntactic abilities and semantic-pragmatic competence in 24 children with developmental dyslexia aged 7 -12 years. Morphosyntactic abilities were investgated in a direct object clitic production task, semantic-pragmatic competence in a quantifier comprehension task. Children with dyslexia produced fewer clitics than their age controls and vocabulary controls. Ten children with dyslexia scored less than 1.5 SD below the mean score of an additional group of 89 children of the same age, selected across a range of oral and reading abilities. No difference was found in quantifier comprehension. These findings suggest that a large number of children with dyslexia are likely to be affected by SLI, although not diagnosed, and the authors recommend language assessment, including assessment of clitic production, when children are referred for dyslexia. By capitalizing on theories that see SLI as a deficit in the processing of complex aspects of linguistic relations, the authors argue that the production of clitics is particularly challenging because of their syntactic and morphosyntactic complexity
Effect of alternate CH4-reducing/lean combustion treatments on the reactivity of fresh and S-poisoned Pd/CeO2/Al2O3 catalysts
No full textThis work investigates the effect of treatments under different CH4-containing atmospheres on the reactivity of fresh and S-poisoned 2% w/w Pd/Al2O3/CeO2 catalysts for methane combustion.
Over the fresh catalyst the decomposition/reformation processes of PdO occurring during cycles of CH4-reducing/lean combustion pulses allowed the complete recovery of activity losses possibly associated with H2O poisoning which were observed during prolonged exposure under lean combustion conditions. The presence of CeO2 markedly enhances both the activity losses under lean combustion conditions and the rate of PdO reoxidation/reactivation upon Pd redox cycle.
Under lean combustion conditions, regeneration of catalyst deactivated by exposure to SO2-containing atmosphere required very high temperatures (above 750 degrees C) in order to decompose stable sulphate species adsorbed on the support. Treatments consisting of alternate CH4- reducing/lean combustion pulses allowed a complete recovery of activity at much lower temperatures (550-600 degrees C) due to the reduction of sulphates by CH4 activated on the surface of Pd metal. A protecting role of CeO2 on Pd poisoning due either to exposure to SO2-containing atmosphere or to spill-back of support sulphates species was also evidenced. (C) 2007 Elsevier B.V. All rights reserved
Regeneration treatments of S-poisoned Pd/Al2O3 and Pd/CeO2/Al2O3 catalysts for the combustion of methane
No full textThis work investigates the regeneration of S-poisoned Pd/Al2O3 and Pd/CeO2/Al2O3 catalysts under different CH4 containing atmospheres. Under lean combustion conditions in the presence of excess O-2, partial regeneration took place for both systems only above 750 degrees C after decomposition of stable sulphate species adsorbed on the support. Under alternate lean combustion/CH4-reducing pulse regeneration is markedly anticipated down to 550-600 degrees C. Experiments evidenced an effective role of certain preventing PdO from sulphation and in promoting regeneration via sulphates decomposition under reducing conditions
Regeneration of S-poisoned Pd/Al2O3 catalysts for the combustion of methane
No full textRegeneration of S-poisoned Pd/Al2O3 catalysts for the abatement of methane emissions from natural gas vehicles was addressed in this work.
Investigations were devoted to determine the temperature threshold allowing for catalyst reactivation under different CH4 containing atmospheres. Under lean combustion conditions in the presence of excess O-2, partial regeneration took place only above 750 degrees C after decomposition of stable sulphate species adsorbed on the support. Short CH4-reducing, O-2-free pulses led to partial catalyst reactivation already at 550 degrees C and to practically complete regeneration at 600 degrees C. Also in this case reactivation was associated with SO2 release due to the decomposition of stable support sulphates likely promoted by CH4 activation onto the reduced metallic Pd surface. Rich combustion pulses with CH4/O-2 = 2 were equally effective to CH4-reducing pulses in catalyst regeneration.
These results suggest that a regeneration strategy based on periodical natural gas pulses fed to the catalyst by a by-pass line might be efficient in limiting the effects of S-poisoning of palladium catalysts for the abatement of CH4 emissions from natural gas engine
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