ESTUDO DA UMIDIFICACAO E DO AQUECIMENTO DOS GASES INSPIRADOS DURANTE A VENTILACAO MECANICA NO CAO

The authors studied the effect of temperature and humidity of inhaled gases on the respiratory tract of dogs submitted to mechanic ventilation. According to these two variables, fourty dogs were divided in five groups: -G1: 22-26°C and 17-20 mg H2O.l-1; G2: 27-31°C and 23-27 mg H2O.l-1; G3: 32-36°C and 30-36 mg H2O.l-1; G4: 37-41°C and 40-49 mg H2O.l-1; G5: 42-46°C and 59-65 mg H2O.l-1. The following parameters were evaluated: medial arterial pressure, cardiac frequency, venous pressure of inferior cava (CVP), endotracheal pressure, arterial pH, PaO2, PaCO2, rectal temperature, and the histology of the tracheobronchial tree. In the groups G1 and G5, the endotracheal pressure and CVP presented a slight raise. In the groups G1, G2 and G3, there was no histological modification or progressive hypothermia. The group G5 presented metabolic acidosis and great histological alteration; in this group the rectal temperature remained stable. The group G4 presented great histological alteration and hypothermia. In conclusion, the temperature and humidity of inhaled gases should not be higher than 36°C and 36 mm H2O.l-1, respectively. However, the stability of body temperature only is achieved when the temperature of the inhaled air is 42°C or higher.

Relativistic quantum thermodynamics of ideal gases in two dimensions

In this work we study the behavior of relativistic ideal Bose and Fermi gases in two space dimensions. Making use of polylogarithm functions we derive a closed and unified expression for their densities. It is shown that both type of gases are essentially inequivalent, and only in the non-relativistic limit the spinless and equal mass Bose and Fermi gases are equivalent as known in the literature.

Experimental aspects of partially premixed pulsating combustion

The pulsating combustion process has won interest in current research due to indications that its application in energy generation can offer several advantages, such as: fuel economy, reduced pollutants formation, increased rate of convective heat transfer and reduced investment, when compared with conventional techniques. An experimental study has been conducted with the objective of investigating the effects of combustion driven acoustic oscillations in the emission rates of combustion gases, especially carbon monoxide and nitrogen oxides. The experiments were conducted in a water-jacketed 1-m long by 25-cm internal diameter stainless steel vertical tube. The combustor operated with liquefied petroleum gas (LPG) in both oscillatory and non oscillatory conditions, under the same input conditions. Part of the reactant mixture was excited acoustically, before the burner exit, by a speaker positioned strategically. The burner was aligned with the chamber longitudinal axis and positioned at its bottom. The experiments were conducted for 0.16 g/s of LPG burning in stoichiometric equivalence ratio. The main conclusions were: a) the pulsating combustion process produces more uniform fuel/air profile than the non pulsating process, b) close to stoichiometric equivalence ratio the pulsating combustion process generates higher rates of NO x; c) the frequency has a strong influence in NO x emission, but the pressure amplitude has a weak influence; d) the presence of the acoustic field may change drastically the combustion gas emissions in diffusion flames, but in pre-mixed flames the influence is not as strong.

Laser ultrasonics system for measurement of speed of sound in gases

In this work we developed a setup to measure the speed of sound in gases using a laser ultrasonics system. The mentioned setup is an all optical system composed by a Q-switched Nd:YAG laser to generate the sound waves, and a fiber optical microphone to detect them. The Nd:YAG provided a laser pulse of approximately 420 mJ energy and 9 ns of pulse width, at the wavelength of 1064 nm. The pulsed laser beam, focused by a positive lens, was used to generate an electrical breakdown (in the gas) which, in turn, generates an sound wave that traveled through a determined distance and reached the fiber optical microphone. The resulting signal was acquired in an oscilloscope and the time difference between the optical pulse and the arrival of the sound waves was used to calculate the speed of sound, since the distance was known. The system was initially tested to measure the speed of sound in air, at room pressure and temperature and it presented results in agreement with the theory, showing to be suitable to measure the speed of sound in gases. © 2012 American Institute of Physics.

Self-trapping of Fermi and Bose gases under spatially modulated repulsive nonlinearity and transverse confinement

We show that self-localized ground states can be created in the spin-balanced gas of fermions with repulsion between the spin components, whose strength grows from the center to periphery, in combination with the harmonic-oscillator (HO) trapping potential acting in one or two transverse directions. We also consider the ground state in the noninteracting Fermi gas under the action of the spatially growing tightness of the one- or two-dimensional (1D or 2D) HO confinement. These settings are considered in the framework of the Thomas-Fermi-von Weizsäcker (TF-vW) density functional. It is found that the vW correction to the simple TF approximation (the gradient term) is nearly negligible in all situations. The properties of the ground state under the action of the 2D and 1D HO confinement with the tightness growing in the transverse directions are investigated too for the Bose-Einstein condensate with the self-repulsive nonlinearity. © 2013 American Physical Society.

Stability of trapped degenerate dipolar Bose and Fermi gases

Trapped degenerate dipolar Bose and Fermi gases of the cylindrical symmetry with the polarization vector along the symmetry axis are only stable for the strength of dipolar interaction below a critical value. In the case of bosons, the stability of such a dipolar Bose-Einstein condensate (BEC) is investigated for different strengths of contact and dipolar interactions using a variational approximation and a numerical solution of a mean-field model. In the disc shape, with the polarization vector perpendicular to the plane of the disc, the atoms experience an overall dipolar repulsion and this fact should contribute to the stability. However, a complete numerical solution of the dynamics leads to the collapse of a strongly disc-shaped dipolar BEC due to the long-range anisotropic dipolar interaction. In the case of fermions, the stability of a trapped single-component degenerate dipolar Fermi gas is studied including the Hartree-Fock exchange and Brueckner-Goldstone correlation energies in the local-density approximation valid for a large number of atoms. Estimates for the maximum allowed number of polar Bose and Fermi molecules in the BEC and degenerate Fermi gas are given. © 2013 IOP Publishing Ltd.

Influence of specimen size, tray inclination and air flow rate on the emission of gases from biomass combustion

Experiments of biomass combustion were performed to determine whether specimen size, tray inclination, or combustion air flow rate was the factor that most affects the emission of carbon dioxide, carbon monoxide, and methane. The chosen biomass was Eucalyptus citriodora, a very abundant species in Brazil, utilized in many industrial applications, including combustion for energy generation. Analyses by gas chromatograph and specific online instruments were used to determine the concentrations of the main emitted gases, and the following figures were found for the emission factors: 1400 ± 101 g kg-1 of CO2, 50 ± 13 g kg-1 of CO, and 3.2 ± 0.5 g kg-1 of CH4, which agree with values published in the literature for biomass from the Amazon rainforest. Statistical analysis of the experiments determined that specimen size most significantly affected the emission of gases, especially CO2 and CO. •Statistical analysis to determine effects on emission factors.•CO2, CO, CH4 emission factors determined for combustion of Eucalyptus.•Laboratory results agreed with data for Amazonian biomass combustion in field tests.•Combustion behavior under flaming and smoldering was analyzed. © 2013 Elsevier Ltd.

Emissão de gases de efeito estufa em áreas de sistema semeadura direta com aportes diferenciados de carbono e nitrogênio

Pós-graduação em Agronomia (Agricultura) - FCA

Uso de filtro de mangas para tratamento de gases resultantes da combustão de bagaço de cana

Pós-graduação em Engenharia Mecânica - FEB

Avaliação do sistema APGAR (modificado por BORN, 1981) e dos níveis de cortisolemia, glicemia e de gases sanguíneos em cabritos nascidos de partos eutócicos e de cesariana

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Composição química, digestibilidade e produção de gases in vitro de cultivares de Brachiaria manejados em diferentes ofertas de forragem

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Balanço de gases de efeito estufa em áreas de cana-de-açúcar sob diferentes cenários de manejo, considerando-se mitigações

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Inventário dos gases de efeito estufa associado ao manejo da cana-de-açúcar na localidade de Barretos-SP, Brasil

Pós-graduação em Agronomia (Produção Vegetal) - FCAV

Avaliação da utilização do atual Diesel (combustível) comercial brasileiro (ano de referência 2003-2004) para motores com gerenciamento eletrônico de combustível e sistema de recirculação de gases de escape (EGR), certificados pela legislação EPA, 2004

Pós-graduação em Engenharia Mecânica - FEG

Composição química, digestibilidade e produção de gases in vitro de três espécies forrageiras tropicais

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)