Meira S.M.M.,Federal University of Rio Grande do Sul |
Meira S.M.M.,Instituto Federal Sul Rio Grandense |
Zehetmeyer G.,Federal University of Rio Grande do Sul |
Werner J.O.,Federal University of Rio Grande do Sul |
Brandelli A.,Federal University of Rio Grande do Sul
Food Hydrocolloids | Year: 2017
Corn starch was used as a polymeric matrix for development of new antimicrobial packaging prepared by casting method and using nisin or pediocin for food preservation. Halloysite clay was selected as nanofiller to promote film reinforcement and a novel approach was tested using bacteriocins adsorbed on nanoclay before incorporation into film forming solutions. Active films against Listeria monocytogenes and Clostridium perfringens were obtained, but halloysite retained antimicrobial activity when comparing to films without nanofiller addition. Results from XRD showed that the addition of bacteriocins affected the crystallinity of starch matrix, whereas SEM images showed that peptides provoked surface irregularities. Adsorption approach proved to be a promise strategy to maintain a certain crystallinity and homogeneous morphology of films and consequently influencing other properties, like improving thermal performance. In the case of nanocomposite with nisin, adsorption procedure also improved water barrier properties. Increased mechanical resistance of films containing halloysite was observed. Elongation at break (EB) increased significantly for samples with nisin or pediocin, and those containing nisin plus halloysite. Physical interactions between additives and starch matrix via hydrogen bonding were evidenced by FTIR. Color parameters L*, a* and b* were close to those obtained for control films, although higher b* values were observed for pediocin samples. These results indicate the potential of such antimicrobial nanocomposite films as food packaging material. © 2016 Elsevier Ltd
Comparative study of the influence of blow-up ratio in the properties of HDPE and LDPE extruded blow films [Estudo comparativo dainfluência darazão de sopro nas propriedades de filmes tubulares de PEBD e PEAD]
Ferreira R.L.R.,Instituto Federal Sul Rio Grandense |
Santana R.M.C.,Federal University of Rio Grande do Sul
Polimeros | Year: 2015
The purpose of this study is to evaluate the influence of the polyolefin type and the blow-up ratio (BUR) on the thermal physical properties of films produced in a blown film extrusion process. It was used low density polyethylene (LDPE) and high density polyethylene (HDPE) processed in a blown film extrusion line at three BUR of: 1.5:1; 2.5:1 and 3.5:1. The results of physical characterization on these films demonstrated that the increase in the BUR shows a higher thickness variation in the perimeter of tubular films and, therefore, optical properties variation. The coefficient of friction (COF) of the films was smaller for HDPE and did not have significant variation with the increase in the BUR applied. Regarding mechanical properties, HDPE films showed higher tensile strength and lower strain values in the yield point, in both directions. The largest BUR showed higher similarity of the tensions and strains between the machine direction (MD) and transverse direction (TD). The ideal BUR observed for films processed with LDPE is 2.5:1, for HDPE this number is higher and close to 3.5:1. The HDPE films showed more opacities and less brightness when compared to LDPE films. The results prove well known values in the literature, however, there was an innovation introduced in this study which is the use of the portable digital thermo graphic technique that allows the instantaneous visualization (on-line) of the temperature variation in the bubble perimeter in the frost line (crystallization or solidification area of the film).
Genetic transformation and the use glyphosate on soil microbial, biological nitrogen fixation, quality and safety of genetically modified soybean [Transformação genética e aplicação de glifosato na microbiota do solo, fixação biológica de nitrogênio, qualidade e segurança de grãos de soja geneticamente modificada]
Bohm G.M.B.,Instituto Federal Sul rio grandense |
Bohm G.M.B.,Federal University of Pelotas |
Rombaldi C.V.,Federal University of Pelotas
Ciencia Rural | Year: 2010
The genetically modified soybean resistant to glyphosate (GMRR) is the main product of plant biotechnology, considering the evolution of the area cultivated and the use of this grain. EUA, Argentina and Brazil are the largest producers of GMRR. The release of GMRR soybean cultivation in Brazil was done based on researches that were accomplished in other countries without the validation of the same edaphoclimatic conditions. In this context, the main researches about environmental impact, plant metabolism, quality and safety of GMRR soybean with or without glyphosate application were collected and investigated. In general, the researches investigated showed some similar characteristics: a) few variables were studied; b) simulations in green house or in vitro are used to infer possible response on the field. Although scarce, the researches denoted that the genetic transformation did not affect soil microorganisms, biological nitrogen fixation and composition of grains. The factor which could affect these variables is the glyphosate application in weed control, thus the risk of damage to the environment and the safety of products derived from this raw materialare due to the use of the herbicide during cultivation, and not to the genetic transformation.
Bacchieri G.,Instituto Federal Sul rio grandense |
Bacchieri G.,Federal University of Pelotas |
Barros A.J.D.,Federal University of Pelotas
Revista de Saude Publica | Year: 2011
The paper describes the situation of road traffic accidents in Brazil since 1998, when a new Brazilian traffic law was approved, up to the year 2010. A review of both academic and non-academic literature was carried out, including journals (both indexed and non-indexed), technical reports, author searches, searches in paper reference lists and direct contact with researchers. The main problems related to road traffic accidents in Brazil identified were the increase in the absolute number of deaths and in the mortality rates, a rapid increase in the number of motorcycles, and drink & driving. Influent authors in the field and centers of expertise were identified. Some potential solutions are presented by the authors, who suggest that the public offices related to traffic regulation and control are not taking suitable measures for control and reduction of road traffic accidents.
Bacchieri G.,Federal University of Pelotas |
Bacchieri G.,Instituto Federal Sul Rio Grandense |
Barros A.J.D.,Federal University of Pelotas |
Dos Santos J.V.,Federal University of Pelotas |
Gigante D.P.,Federal University of Pelotas
Accident Analysis and Prevention | Year: 2010
In 2006, we carried out a cross-sectional study in the urban area of Pelotas, Southern Brazil, with the aim of outlining the profile of bicycle commuters, analyzing their use of safety equipment and risk behaviors and the association between these variables and involvement in traffic accidents in the previous 12 months. This study was based on the baseline survey carried out prior to an educational intervention aimed at reducing accidents among cyclists. The sample included 1133 male subjects aged 20 years or more, and who used a bicycle for commuting. Crude and adjusted analyses were carried out using Poisson regression. We recorded a total of 152 reported traffic accidents in the 12 months preceding the interview, involving 10.8% of subjects. Most risk behaviors studied and the use of safety equipment showed no significant association with accidents. Only commuting by bicycle seven days per week, as opposed to five or six, and a combination of extremely imprudent behaviors such as zigzagging through traffic, riding after ingesting alcohol, and high-speed riding were found to be risk factors for accidents. Our findings suggest that in the context where the study was done (poor road signaling, limited policing, aggressive driving) changing cyclist behavior may not have substantial impact in terms of accident reduction before other road traffic interventions are implemented. © 2009 Elsevier Ltd.
Teixeira S.S.,Instituto Federal Sul Rio Grandense |
dos reis A.V.,Federal University of Pelotas |
Machado A.L.T.,Federal University of Pelotas
Engenharia Agricola | Year: 2013
This study aimed to evaluate the effect of horizontal plate meter with oblong holes operating with one or two seed outlets at different speeds over the accuracy of longitudinal distribution of common bean seeds (Phaseolus vulgaris L.). The experiment was performed in laboratory using the meter with one and two seed outlet points in relation to ten tangential disk plate speeds (0.03 to 0.30 m s-1). It was used a complete randomized design with four replications, summing up 80 experimental treatments. Tangential speed quantitative factor was estimated through a 2nd order polynomial regression. There was no significant difference in the behavior of the seed meter operating with one or two outlets in the metering of bean seeds in all tested speeds, with percentage of single seeds spacing over 60% in tangential speeds below of 0.24 m s-1.
Bregolin F.L.,Federal University of Rio Grande do Sul |
Sias U.S.,Instituto Federal Sul rio grandense |
Behar M.,Federal University of Rio Grande do Sul
Journal of Luminescence | Year: 2013
The present work deals with the photoluminescence (PL) emitted from Eu and Tb ions implanted at room temperature (RT) up to 350°C in a SiO2 matrix, followed by a further anneal process. The ions were implanted with energy of 100 keV and a fluence of 3×1015 ions/cm. Further anneals were performed in atmospheres of N2 or O2 with temperatures ranging from 500 up to 800°C. PL measurements were performed at RT and structural measurements were done via transmission electron microscopy (TEM). In addition, the Rutherford backscattering technique (RBS) was used to investigate the corresponding ion depth profiles. For Tb, the optimal implantation temperature was 200°C, and the anneal one was of 500°C. Under these conditions, the PL yield of the sharp band centered at 550 nm was significatively higher than the one obtained with RT implants. The PL spectra corresponding to the Eu ions show two bands, one narrow centered around 650 nm and a second broad one in the blue-green region. The implantation temperature plays a small influence on the PL shape and yield. However, the annealing atmosphere has a strong influence on it. Samples annealed in N2 present a broad PL band, ranging from 370 up to 840 nm. On the other hand, the O2 anneal conserves the original as-implanted spectrum, that is: a broad PL band in the blue-green region together with sharp PL band in the red one. For both ions, Tb and Eu, the TEM analyses indicate the formation of nanoclusters in the hot as-implanted samples. © 2012 Elsevier B.V.
Moreira D.M.,Federal University of Santa Catarina |
Moreira D.M.,Federal University of Espirito Santo |
Moraes A.C.,Instituto Federal Sul Rio Grandense |
Goulart A.G.,Federal University of Pampa |
Albuquerque T.T.D.A.,Federal University of Espirito Santo
Atmospheric Environment | Year: 2014
An integral solution of the atmospheric diffusion equation considering wind speed as a function of vertical height and eddy diffusivity as a function of both downwind distance from the source and vertical height is presented. The near-source dispersion problem is investigated comparing a vertical eddy diffusivity function of distance from the source against their asymptotic limit. The results suggest that the inclusion of the memory effect as modeled by Taylor's theory, improves the description of the turbulent transport process of atmospheric effluent released by a low continuous source in convective conditions. © 2013 Elsevier Ltd.
Galup-Montoro C.,Federal University of Santa Catarina |
Schneider M.C.,Federal University of Santa Catarina |
MacHado M.B.,Federal University of Santa Catarina |
MacHado M.B.,Instituto Federal Sul Rio Grandense
IEEE Transactions on Circuits and Systems II: Express Briefs | Year: 2012
This letter presents MOS analog circuits that can operate with very low supply voltages. Operation of the MOS transistor in the triode region is emphasized owing to the limited voltages available. Special attention has been given to the properties of the zero-VT transistor due to its high drive capability at low voltages. Simulation and measurement results for a Colpitts oscillator prototype set up around a zero-VT MOSFET demonstrated that the oscillator operates with supply voltages lower than the thermal voltage kT/q. Finally, ultra-low-voltage rectifiers using diodes or diode-connected MOSFETs operating in weak inversion are analyzed. © 2004-2012 IEEE.
Kremer M.M.,Instituto Federal Sul Rio Grandense |
Kremer M.M.,Federal University of Pelotas |
Reichert F.F.,Federal University of Pelotas |
Hallal P.C.,Federal University of Pelotas
Revista de Saude Publica | Year: 2012
Objective: To evaluate the intensity and duration of physical efforts in Physical Education classes in primary and secondary school. Methods: School-based cross-sectional study carried out by means of the observation of 218 Physical Education classes, including a total of 272 students (each one of the students was evaluated three times). The study was carried out in the city of Pelotas (Southern Brazil), between August and December 2009. In order to evaluate the intensity of the efforts, accelerometers were used and the following cut-off points were adopted (in counts per minute): sedentary activities (0-100), light activities (101-2,000), moderate (2,001-4,999), vigorous (5,000-7,999), and very vigorous activities (>8000). Results: The mean duration of the classes was 35.6 minutes (SD 6.0). The mean proportion of time spent in moderate to vigorous physical activity was 32.7% (SD 25.2). Boys (44.1%) were involved signifi cantly more in moderate to vigorous physical activity as compared to girls (21.0%; p<0.01). Students who practice physical activities outside the classes participated more in moderate to vigorous physical activity in the Physical Education classes. Conclusions: Besides the fact that Physical Education classes have a short duration, students practice moderate to vigorous physical activity during one third of the class, with a poor signifi cant contribution to students' level of physical activity.