Reduction of pollutants emissions on si engines : accomplishments with efficiency increase

This paper presents an experimental study aiming to identify the means to minimize the reduction of the overall performance of a gasoline engine when employing the Exhaust- Gas Recirculation (EGR) technique that reduces NOx emissions. The increase of the compression ratio and turbocharging was evaluated as a mean to recover the original performance. The formation of pollutants and the engine performance were verified at full and partial loads. The results show that the combination of exhaust gas recirculation with turbocharger or through an increase of the compression ratio enhance the relation between the engine performance and the emission of NO. However, the turbocharger seemed to be more sensitive to the negative effects of the EGR technology

Signature for heavy Majorana neutrinos in hadronic collisions

The production and decay of new possible heavy Majorana neutrinos are analyzed in hadronic collisions. New bounds on the mixing of these particles with standard neutrinos are estimated according to a fundamental representation suggested by grand unified models. A clear signature for these Majorana neutrinos is given by same-sign dileptons plus a charged weak vector boson in the final state. We discuss the experimental possibilities for the future Large Hadron Collider (LHC) at CERN.Comment: Latex2e(epsfig), 12 pages, 8 figures, to appear Physical Review

Neutral heavy lepton production at next high energy e+e−e^+e^- linear colliders

The discovery potential for detecting new heavy Majorana and Dirac neutrinos at some recently proposed high energy $e^+e^-$ colliders is discussed. These new particles are suggested by grand unified theories and superstring-inspired models. For these models the production of a single heavy neutrino is shown to be more relevant than pair production when comparing cross sections and neutrino mass ranges. The process $e^+e^- \longrightarrow {\nu} e^{\pm} W^{\mp}$ is calculated including on-shell and off-shell heavy neutrino effects. We present a detailed study of cross sections and distributions that shows a clear separation between the signal and standard model contributions, even after including hadronization effects.Comment: 4 pages including 15 figures, 1 table. RevTex. Accepted in Physical Review

Efeito da temperatura e umidade sobre a infeccao de seringueira (Hevea spp.) por Microcyclus ulei.

Foi desenvolvida uma equacao de regressao multipla relacionando temperatura e periodo de molhamento foliar sobre a infeccao de seringueira por Microcyclus ulei

First report of human Thelazia callipaeda infection in Portugal

The zoonotic parasitic nematode Thelazia callipaeda, also known as the oriental eye worm, is endemic in several European countries, including Portugal. Infections may result in ocular disease in domestic and wild animals as well as humans, with more or less severe manifestations. We report the first human case of ocular thelaziosis by T. callipaeda in Portugal, a country where the parasite had already been found to infect dogs, cats, red foxes, wild rabbits and a beech marten. An 80-year-old patient from east-central Portugal, who had been suffering from tearing for a few years, had whitish filiform fragments removed from the left eye. Polymerase chain reaction of partial cytochrome c oxidase subunit 1 and 18S small subunit rRNA genes followed by bidirectional sequencing and BLAST analysis confirmed T. callipaeda haplotype 1, the only haplotype previously reported in Europe. The endemicity of T. callipaeda in domestic and wild animals in east-central Portugal makes it very likely that infection of the human patient had occurred locally. In east-central and other geographical areas of Portugal, veterinarians and physicians, especially ophthalmologists, should regard T. callipaeda as a cause of ocular pathology in animals and humans. © 2022This work was supported by national funds, through Fundação para a Ciência e Tecnologia (FCT, Portuguese Foundation for Science and Technology), under projects UIDB/CVT/00772/2020 and LA/P/0059/2020, and also projects UIDB/04750/2020 and LA/P/0064/2020

Epidemiologia do mal das folhas da seringueira. I. Ponte Nova-MG.

Acompanhou-se o progresso do mal das folhas, em condicoes de campo, durante um (1) ano. Concomitantemente, registratam-se a umidade relativa do ar, a temperatura, a duracao de molhamento foliar e a precipitacao pluvial

CASE STUDY: THE LIGNOCELLULOSIC COMPONENTS INTERFERENCES IN THE THERMAL BEHAVIOR OF BRAZILIAN SAVANA BIOMASS

The residual biomass has become increasingly important in the energy scenario due to its energetic potential and easy acquisition in isolated communities. The heterogeneous nature of biomass makes the analysis of its composition a relevant factor in the development of thermochemical processes. Several researchers show that understanding this heterogeinidade of biomass can be a strategy for optimization and search efficiency of thermochemical processes, since it is possible to predict the results and in addition, the reactor design based on the characteristics of biomass. In this context, the purpose of this work was to study the behavior of three biomass of the Brazilian savana - Dipteryx alata (baru), Hymenaea stigonocarpa (jatobá-do-cerrado) and Caryocar brasiliense (pequi), comparing the lignocellulosic results with the thermal behavior obtained by thermogravimetric analysis. The analysis were compared with results of several researchers, confirming that those analysis are parameters that influence the yield of the desired product. The results of this work elucidate that the moisture and extractives content of pequi is greater than the other biomass and that the temperature peak of cellulose and lignin from all biomass in this study are quite close. However, the hemicellulose’s temperature peak of pequi is lower than baru and jatobá’s temperature peak. Moreover, the results showed that the composition of the lignocellulosic biomass is an extremely important factor in selecting the greater reactivity material