The GRAAL high resolution BGO calorimeter and its energy calibration and monitoring system

We describe the electromagnetic calorimeter built for the GRAAL apparatus at the ESRF. Its monitoring system is presented in detail. Results from tests and the performance obtained during the first GRAAL experiments are given. The energy calibration accuracy and stability reached is a small fraction of the intrinsic detector resolution.Comment: 19 pages, 14 figures, submitted to Nuclear Instruments and Method

NOx Removal Catalysis

This paper surveys the most important catalytic emission control technologies being employed or near commercialization for the removal of nitrogen oxides (NOx) from the exhausts of mobile sources under lean conditions. Urea/Ammonia-SCR systems and NOx Storage/Reduction (NSR) catalysts will be addressed, with particular attention to the specific demands related to the mobile applications. In the first part of the paper the transient kinetics of standard de-NOx SCR reaction over commercial V-W/Ti SCR catalysts and the dynamic model of the honeycomb reactor will be addressed. Then the validation of the dynamic model with integral reactor measurements and full-scale transients in vehicles will be illustrated. The second part presents a complete and quantitative understanding of the NOx storage chemistry of a Pt-Ba/Al2O3 “Lean NOx Trap” catalyst

Labeled 15NO Study on N2 and N2O Formation Over Pt–Ba/Al2O3 NSR Catalysts

Mechanistic aspects involved in the formation of N2 and of N2O during the reduction of NO, stored nitrites and stored nitrates in the presence of NO are investigated in this work by means of isotopic labeling experiments over a model PtBa/Al2O3 NSR catalyst. The reduction of gaseous labeled NO with unlabelled NH3 leads to the formation of N2O at low temperature (below 180 °C), and of N2 at high temperature. All N2 possible isotopes are observed, whereas only labeled molecules have been detected in the case of N2O. Hence the formation of nitrous oxide involves undissociated NO molecules, whereas that of N2 can be explained on the basis of the statistical coupling of 15N- and 14N-adatoms on Pt. However, due to a slight excess of the mixed 15N14N isotope, a SCR-like pathway likely operates as well. The reduction of the stored labelled nitrates is very selective to N2 and all isotopes are observed, confirming the occurrence of the recombination pathway. However also in this case a SCR-like pathway likely occurs and this explains the abundance of the 14N15N species. When the reduction of the stored nitrates is carried out in the presence of NO, this species is preferentially reduced pointing out the higher reactivity of gaseous NO if compared to the nitrates

Mechanistic investigation of the reduction of NOx over Pt-and Rh-based LNT catalysts

The influence of the noble metals (Pt vs. Rh) on the NOx storage reduction performances of lean NOx trap catalysts is here investigated by transient micro-reactor flow experiments. The study indicates a different behavior during the storage in that the Rh-based catalyst showed higher storage capacity at high temperature as compared to the Pt-containing sample, while the opposite is seen at low temperatures. It is suggested that the higher storage capacity of the Rh-containing sample at high temperature is related to the higher dispersion of Rh as compared to Pt, while the lower storage capacity of Rh-Ba/Al2O3 at low temperature is related to its poor oxidizing properties. The noble metals also affect the catalyst behavior upon reduction of the stored NOx, by decreasing the threshold temperature for the reduction of the stored NOx. The Pt-based catalyst promotes the reduction of the adsorbed NOx at lower temperatures if compared to the Rh-containing sample, due to its superior reducibility. However, Rh-based material shows higher reactivity in the NH3 decomposition significantly enhancing N2 selectivity. Moreover, formation of small amounts of N2O is observed on both Pt- and Rh-based catalyst samples only during the reduction of highly reactive NOx stored at 150 °C, where NOx is likely in the form of nitrites

Efeito do dano mecânico na qualidade fisiológica e na capacidade de expansão de sementes de milho pipoca.

Com o objetivo de dar subsidio aos produtores de sementes e/ou graos de milho pipoca, para melhorar a qualidade fisiologica da producao, sementes da cultivar CMS-43 foram submetidas a tres niveis de danificacao mecanica (sem danos, com danos e com danos dobrados), e avaliadas pelos testes de germinacao, vigor (condutividade eletrica) e capacidade de expansao. Os resultados demonstraram que sementes danificadas reduzem significativamente a germinacao, o vigor e a capacidade de expansao das sementes. Concluiu-se que indiferente a finalidade da producao, sementes e/ou graos, a colheita do milho pipoca precisa ser feita com o minimo de danificacao mecanica possivel, para propiciar um produto com maxima qualidade

Encapsulation Techniques and Traffic Characterisation of an Ethernet-Based 5G Fronthaul

This paper first overviews how, in the 5G Next Generation Radio Access Network (NG-RAN), the Next generation NodeB (gNB) functions are split into Distributed Unit (DU) and Central Unit (CU). Then it describes the proposed fronthaul transport solutions, such as Common Packet Radio Interface (CPRI), eCPRI, IEEE P1914.3 and their relationship with the Ethernet protocol. Finally, a characterisation of the traffic generated by the fronthaul is presented. Such characterisation may guide in the selection of the right network for fronthaul transport.This work has been partially funded by the EU H2020 “5G-Transformer” Project (grant no. 761536)