Time filter

Source Type

Neves E.F.,Federal University of Grande Dourados
Genetics and molecular research : GMR | Year: 2012

One of the most important attributes that allowed the evolution and maintenance of sociality in insects is their ability to distinguish members of their own colonies. The capacity for individual recognition in social insects is mediated by chemical signals that are acquired soon after the adult emerges, and vary according to the tasks performed by individuals in their colonies. We determined the time when adults of the wasp Mischocyttarus consimilis acquire the chemical signature of their colonies, as well as the variation in the cuticular hydrocarbon profiles of the exoskeleton of individuals, according to their functions in the colony. The method used was Fourier transform infrared photoacoustic spectroscopy directly on the gaster of each individual. Young wasps take three to four days to acquire the colony's chemical signature, with a small change on the fifth day, when the cuticular hydrocarbon profile of the workers is more similar to that of the queens than that of the males, probably because they are of the same sex, but primarily because of the similarity of tasks executed by these two groups of females in the colonies. Source

The aim of this paper is to present aspects about the energy balance of sugarcane crops and its carbon dioxide emissions. We calculate energy used in agricultural, industrial and distribution sectors by five sugarcane mills of Mato Grosso do Sul and we compare the yield with its energy delivery. The energy balance obtained, with an average 6.8, shows that is advantageous to produce ethanol in the lands of that Brazilian state. We have prepared a forecasting of electricity production from bagasse taking into account two types of technology. Finally, we present the potential value of CO2 emitted by the five mills to evaluate greenhouse gas emissions of the ethanol production valor chain. © 2012 Elsevier Ltd. Source

Serra H.,Federal University of Grande Dourados
Neotropical entomology | Year: 2011

We combined two models to investigate the theoretical dynamics of five exotic and native blowfly species in response to the Allee effect by using demographic parameters estimated from experimental populations. Most of the results suggest stabilization of dynamic behavior in response to the Allee effect. However, the results depended on the magnitude of the demographic parameters of each species, and also indicated chaotic fluctuations and limit cycles. The results are discussed in the context of larval aggregation, an important biological process for blowflies, which naturally incorporates the Allee effect. Source

De Souza A.C.C.,Federal University of Grande Dourados | Silveira J.L.,Sao Paulo State University
Renewable and Sustainable Energy Reviews | Year: 2011

Various reports concerning catalytic reaction of glycerol for hydrogen production is available. However, economic analyses of this activity are not found yet. The objective of this work is to evaluate the process of hydrogen production via steam reforming of glycerol obtained through transesterification process of bio-oils. The thermochemical process of steam reforming process was determined due to high efficiency, feasibility and lower cost of design, development, operation and maintenance. These bio-oils come from feedstocks largely encountered in Brazil such as soybean, palm, castor bean, peanut and cotton seed as also come from residues such as defective coffee, tallow beef, wastewater (scum) and others. Various findings were obtained such as potential of production of glycerol utilizing residues (considering available amounts in the Brazilian states) and some vegetable feedstocks (considering production of harvested feedstock per hectare). Subsequently, production of hydrogen via steam reforming of generated glycerol, and foreseen electricity production via fuel cells were also determined. An additional estimation was paid for production of H-BIO, an innovative fuel developed by PETROBRAS (Petróleo Brasileiro S.A.), where hydrogen and bio-fuel are utilized and generates propane as co-product. About this work, it was concluded that high amounts of hydrogen and electricity could be produced considering an enormous potential from each cited feedstock being an attractive alternative as distributed electricity source and as an additional source for some activities, inclusively those that produce their own feedstocks such as abattoirs (beef tallow), and wastewater treatment plants. © 2010 Elsevier Ltd. All rights reserved. Source

Caires A.R.L.,Federal University of Grande Dourados | Lima V.S.,Federal University of Grande Dourados | Oliveira S.L.,Federal University of Mato Grosso do Sul
Renewable Energy | Year: 2012

In a recent paper published by our group (M.D. Scherer et al. J. Fluoresc. 21 (2011) 1027-1031), we showed that fluorescence spectroscopy has a potential to be used to determine the biodiesel content in the diesel/biodiesel blends. However, this method presents some challenges that must be overcome to be successfully applied. For instance, the method must work with biodiesel produced from different vegetable oils and fats. In the present study, we evaluated the ability of fluorescence spectroscopy to quantify the biodiesel concentration in diesel/biodiesel blends prepared from different feedstocks. Four different blends prepared using biodiesel produced from four refined vegetable oils (canola, sunflower, corn, and soybean) were used in the present investigation. For all samples, the fluorescence spectra were collected between 300 and 800 nm when excited at 260 nm. Our results revealed that the four blends presented a similar emission profile with a maximum at 470 nm. Furthermore, the same fluorescence behavior (emission intensity as a function of biodiesel content) was observed for all blends. Therefore, the results showed that fluorescence-based method for quantifying the biodiesel content in the diesel/biodiesel blends is independent of the refined vegetable oil used in the biodiesel production. © 2012 Elsevier Ltd. Source

Discover hidden collaborations