Study of Gaseous Emissions Derived from the Combustion of Diesel/Beef Tallow Biodiesel Blends

Air pollution is one of the main environmental problems of modern society. The road and transportation segment is a key source of polluting gases worldwide. In its research for transportation’s emission reduction alternatives, the Brazilian government instituted a wide-spread biodiesel, adding 7% (B7) of biodiesel to the diesel used in the country. Therefore, studies such as this must be carried out to guarantee the environmental sustainability of the new matrix of renewable energies, with the useof biofuels, as well as evaluate the gases emitted to for the environment by the combustion of the same ones. This work was detected CO, CO2 and NO gas emissions released into the atmosphere from the combustion of blends diesel/beef tallow biodiesel in a bench-scale engine. Using electrochemical sensors, the of these gases concentration were successfully registered for two modes of operation of the engine diesel, low rotation, 3500 rpm, and high rotation, 7000 rpm. The CO levels in this experiment in low rotation varied between values minimum and maximum range of 866.7 to 1333.3 ppm, and in high rotation, ranging of 666 and 1000 ppm respectively. For the CO2 concentration in low rotation varied between values minimum and maximum range of 2.1 to 2.4%, and high rotation, ranging of 2.2 to 2.5%, and for NO concentrations of the samples for the mode low rotation had a variation of 83 to 109.5 ppm, and for high rotation were 81.7 to 98.7 ppm respectively

Oscillating Economic Sphere: Sustainable Limits of the Biosphere in the Face of Climate Change

This paper proposes a new geometric model to facilitate the understanding of the complex interaction between the economic system and the limits of the biosphere. The concept of the oscillating economic sphere is based on a central parameter of the economy, the Gross Domestic Product (GDP). In the model a hypothetical sphere was built, in which its radius (re) corresponds to the world GDP (economic sphere), and another hypothetical sphere with radius (rb) is also introduced to represent the size of the biosphere (sphere of life), on this geometric construction, these spheres are concentric (rb > re). Therefore, an expansion of the economic sphere will occupy the biosphere, since the fundamentals of economy predict unlimited growth of GDP. Thus we will have a limit to be reached because the biophysical forces oppose this expansion, creating harmful environmental effects such as climate change

Photoacoustic Monitoring of Internal Plastification in Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Copolymers: Measurements of Thermal Parameters

Basic data on thermophysical properties of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) copolymers poly(3HB-co-3HV) were investigated with the aim of understanding the role of 3-hydroxyvalerate monomeric units (3HV) incorporated during random copolymerization. The results show strong evidence that internal plastification is produced by the introduction of 3HV units in the copolymer. It was observed that copolymer thermal conductivity increased approximately linearly with the 3HV content. On the other hand, thermal diffusivity was very sensitive to the change in the copolymer composition showing a sudden rise that attained a saturation plateau. Amplitude-frequency plots indicate that a thermoelastic bending mechanism is operating. In this paper a new photoacoustic arrangement for the measurement of thermal effusivity is presented

Photoacoustic Monitoring of Internal Plastification in Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Copolymers: Measurements of Thermal Parameters

Basic data on thermophysical properties of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) copolymers poly(3HB-co-3HV) were investigated with the aim of understanding the role of 3-hydroxyvalerate monomeric units (3HV) incorporated during random copolymerization. The results show strong evidence that internal plastification is produced by the introduction of 3HV units in the copolymer. It was observed that copolymer thermal conductivity increased approximately linearly with the 3HV content. On the other hand, thermal diffusivity was very sensitive to the change in the copolymer composition showing a sudden rise that attained a saturation plateau. Amplitude-frequency plots indicate that a thermoelastic bending mechanism is operating. In this paper a new photoacoustic arrangement for the measurement of thermal effusivity is presented

Effects of ozone exposure on ?golden? papaya fruit by photoacoustic phase-resolved method : physiological changes associated with carbon dioxide and ethylene emission rates during ripening.

This work addresses the effects of ozone activity on the physiology of ?Golden? papaya fruit. Depth profile analysis of double-layer biological samples was accomplished using the phase-resolved photoacoustic spectroscopy. The feasibility of the method was demonstrated by singling out the spectra of the cuticle and the pigment layers of papaya fruit. The same approach was used to monitor changes occurring on the fruit during ripening when exposed to ozone. In addition, one has performed real time studies of fluorescence parameters and the emission rates of carbon dioxide and ethylene. Finally, the amount of pigments and the changes in waxy cuticle have been monitored. Results indicate that a fruit deliberately subjected to ozone at a level of 6 ppmv underwent ripening sooner (at least 24-48 h) than a fruit stored at ambient conditions. Moreover, ozone caused a reduction in the maximum quantum yield of photosynthetic apparatus located within the skin of papaya fruit. VC 2011 American Institute of Physics