Search

Cactus pear biomass has the potential for bioethanol production in dry regions. However, its low solids concentration and pH variations may hinder the process of alcoholic fermentation. The objectives of this study were as follows: (1) to evaluate the effects of harvest time and season on biomass pH and dry matter concentration of cladodes of two cactus pear species commonly used as forage (Nopalea cochenilliferaand Opuntia stricta); (2) to compare the hydrolysis of fresh and dried biomass (10% w v−1solids); (3) to compare increasing periods of two temperatures (65 °C or 105 °C) to concentrate the biomass to 10% and 30% solids; and (4) to perform enzymatic hydrolysis and fermentation of biomass dried to 30% solids. Biomass pH ranged from 3.0 to 5.6, from early morning to late afternoon, with higher diurnal variation during the dry season, when their solids concentrations were higher than in the rainy season (12–16% × 7–10%). Hydrolyzed fresh and dried biomass had similar glucose, xylose, and galacturonic acid concentrations. Drying at 105 °C for 12 h was the best temperature and period to reach 30% of solids. The enzymatic hydrolysis of the biomass dried to 30% solids yielded 65.3 and 80.0 g of glucose L−1. After fermentations (33 °C; 8 h; Saccharomyces cerevisiae), ethanol was produced to 29.4 and 37.5 g L-1from N. cochenilliferaand O. strictabiomasses, respectively. Therefore, early morning during the dry season is the best moment to harvest the cladodes, whose biomass can be partially dried at 105 °C for 12 h to 30% solids load before being hydrolyzed and fermented for bioethanol production. This procedure reduces the time, energy, and inputs needed in the process.

The present study aimed to evaluate the process of anaerobic co-digestion of different proportions of food waste and fresh bovine manure. The experiments were carried out in the laboratory (using 250-mL reactors) and in a pilot-scale biodigester (8 m3). The laboratory experiment was conducted with batch feed systems testing three food waste (FW) and bovine manure (BM) ratios: 0:1, 1:2, and 3:1 (equivalent to 0, 33, and 75 % of food waste in the digester substrate, respectively). The pilot-scale biodigester had a continuous feed system and received a 1:2 FW:BM mixture ratio. The highest accumulated biogas production in the laboratory was 273 mL g-1of volatile solids (VS) in the treatment with the 1:2 FW:BM ratio. Concentrations of volatile fatty acids (VFA) greater than 8 g L-1inhibited methane production, except in the treatment without food waste. In the pilot-scale biodigester, concentrations of VFA were below the inhibitory threshold, and the biogas and methane yields were 271 L kgVS-1and 220 L kgVS-1, respectively. Therefore, food waste can be successfully co-digested with fresh bovine manure in continuous feed digesters, with an initial organic load rate of at least 2.74 kgVS m-3day-1. Future studies should aim to test progressive increases in food waste load to identify the threshold for inhibition.

Actually, it is necessary developed solutions to minimize the urban freight transportation problems, reducing the occurrence of situations that compromise or even interrupt deliveries and lead to economic losses and inconvenience to everyone involved, from suppliers to the final recipient. In this context, this study analyses the characterists of mobile application for urban freight transport through an exploratory study in Belo Horizonte. The results indicated the technology and cost are important characteristics for mobile application. After this, we develop a mobile application considering the aspirations of its potential users.

Reduction in the activity of the α-amylases which hydrolyze starch and glycogen has been proposed for diminishing the incidence of obesity and diabetes. Many plant extracts contain inhibitors of α-amylases and α-glucosidases and several molecules with this activity have been identified. The present work attempts at investigating if several natural compounds (flavonoids and phenolic acids) that have been reported to be inhibitors of those hydrolytic enzymes can also inhibit starch absorption in vivo. The starch tolerance test in mice was used for assaying starch absorption after administration of 100 mg/kg of five flavonoids (epicatechin, catechin, rutin, quercetin, naringenin) and five phenolic acids (gallic, syringic, vanillic, sinapic, ferulic), which are known in vitroinhibitors of α-amylases. Among the flavonoids, only rutin inhibited starch absorption in mice, even though its effect was only 33% of that one found for the positive control acarbose. Among the five phenolic acids tested only syringic acid produced a clear diminution in starch absorption, which was 47% of that one found with acarbose. On the other hand, other three phenolic acids, namely gallic, sinapic and ferulic acid, caused delay in the absorption of starch, which was characterized by a shift in the time peak of maximal blood glucose concentration, with no modification in the excess of glucose that effectively entered the circulation. Attempts at detecting eventual synergisms by administrating mixtures of flavonoids and phenolic acids were unsuccessful. These results recommend careful translation of in vitrodata on the inhibition of α-amylases and α-glucosidases to the in vivoconditions.

The mobility policies adopted throughout Brazilian history have become inefficient due to the rapid and usually disordered growth of urban areas. Thus, those mobility policies must be revised and adapted considering the new dynamics of the environment. Studies of population displacements identify patterns of urban travel considering the origin, destination, time, reason and transportation mode. The Origin/Destination (OD) survey allows knowing the characteristics of daily trips considering its reason and the mode of transportation used. Those mapped information offer a picture of mobility in the region and represent an important step towards improving transportation and quality of life. The traditional methods to perform OD survey often results in low response rate because of the responder and its lack of interest, usually justified by the time taken to answer the questionnaire. However, the increasing digital inclusion becomes an enabler for online surveys: in Brazil, 51.2% of the surveyed population have access to mobile phones, landline phones, computers and internet at home (FGV, 2011), which is a great stimulus to the application of surveys using digital media. In this context, this paper shows the results of the response rate of online surveys, analyzing its accession and reliability and not ignoring the existence of both difficulties and benefits compared to traditional data collection methods. The reason for evaluating this type of application is, in the first place, its potential in data collection. The online OD survey was tested to obtain OD data to Federal University of Minas Gerais (UFMG) - Campus Pampulha.