Schwarz A.P.,Federal University of Rio Grande do Sul |
Perez Bergmann C.,Federal University of Rio Grande do Sul |
Computational and Theoretical Chemistry | Year: 2017
This work presents an original study of the structural and electronic properties of doped single-walled carbon nanotubes (SWCNT) through titanium complexes and the possibility of adsorption and reduction of hexavalent chromium Cr(VI) using density functional theory. Cr(VI) is one of the major environment pollutants, its removal presents several difficulties, and it results in industrial pollution, causing health problems. The adsorption of Cr(VI) was investigated from the chromate and dichromate molecules in semiconductor SWCNT functionalized with TiO2, TiO4H4 and Ti2O6H4 complexes. The results suggest that the functionalized SWCNT are great candidates to adsorb Cr(VI) from the environment, because of their structural diversity, large specific surface area, small size, good chemical stability, low density, possible regeneration and reusability. In addition, the electronic band structures changed in the region near the Fermi energy of the valence and conduction bands for the pristine and functionalized SWCNT with chromium systems. After adsorption of Cr(VI) in the systems, the formation of molecules with less toxicity and carcinogenic activity is observed. © 2017 Elsevier B.V.
Buriol G.A.,Centro Universitario Franciscano |
Estefanel V.,UNIFRA |
Heldwein A.B.,Federal University of Santa Maria |
Prestes S.D.,Instituto Nacional Of Meteorologia Inmet |
Horn J.F.C.,Centro Universitario Franciscano
Ciencia Rural | Year: 2012
Coefficients a and b of the Angströn - Prescott equation to estimate global solar radiation for Santa Maria, RS were determined. Daily data of global solar radiation and sunshine, were obtained from the Meteorological Station which belongs to the 8th District of Meteorology, located on the campus of the Federal University of Santa Maria - UFSM, period from 2002 to 2008. The mentioned data were copied from the database of the 8th District of Meteorology - 8th DISME in Porto Alegre. Top of atmosphere radiation and possible maximum sunshine were calculated considering local latitude. With such elements, monthly regression equations were determined for the estimation of solar radiation as a function of insolation. We found a high correlation between insolation and global solar radiation and it's possible to estimate the solar radiation depending on the measured insolation.
Machado Junior J.E.S.,UNIFRA |
Seger F.C.,Faculdade Don Bosco |
Teixeira C.S.,Unica |
Pereira E.F.,UDESC |
Merino E.A.D.,Federal University of Santa Catarina
Producao | Year: 2012
This research identified the musculoskeletal complaints of 16 financial institution workers, inserted and not inserted in labor gymnastic activities, through mean body map questionnaires. The Chi-Square test was applied to data analysis with 5% significance level. The labor gymnastic group showed positive results only for the cervical region analysis (p = 0.049). In the cervical region, the labor gymnastic group showed less intense complaints (44.44%; n = 4), in contrast to the non-gymnastic group. These workers, in turn, more intensely complained as moderate (intensity 3) (42.86%; n = 3) and considerable (intensity 4) (57.14%; n = 4). Labor gymnastic practices, performed twice a week, did not bring significant differences in musculoskeletal complaints in the analyses of most body regions. These results indicate the need for adjustments in the activities so that greater effectiveness in the musculoskeletal situation can be achieved.
Machado F.M.,Federal University of Rio Grande do Sul |
Bergmann C.P.,Federal University of Rio Grande do Sul |
Fernandes T.H.M.,Federal University of Rio Grande do Sul |
Lima E.C.,Federal University of Rio Grande do Sul |
And 3 more authors.
Journal of Hazardous Materials | Year: 2011
Multi-walled carbon nanotubes and powdered activated carbon were used as adsorbents for the successful removal of Reactive Red M-2BE textile dye from aqueous solutions. The adsorbents were characterised by infrared spectroscopy, N 2 adsorption/desorption isotherms and scanning electron microscopy. The effects of pH, shaking time and temperature on adsorption capacity were studied. In the acidic pH region (pH 2.0), the adsorption of the dye was favourable using both adsorbents. The contact time to obtain equilibrium at 298K was fixed at 1h for both adsorbents. The activation energy of the adsorption process was evaluated from 298 to 323K for both adsorbents. The Avrami fractional-order kinetic model provided the best fit to the experimental data compared with pseudo-first-order or pseudo-second-order kinetic adsorption models. For Reactive Red M-2BE dye, the equilibrium data were best fitted to the Liu isotherm model. Simulated dyehouse effluents were used to check the applicability of the proposed adsorbents for effluent treatment. © 2011 Elsevier B.V.
Buriol G.A.,Centro Universitario Franciscano |
Stefanel V.,UNIFRA |
Swarowsky A.,UNIFRA |
Ciencia Rural | Year: 2013
The objective of this research was to determine the minimum number of years with observations needed to obtain the medium number of total monthly consistent precipitation values and the area of coverage of the pluviometric station located in the Vacacaí river watershed, in the Rio Grande do Sul state, Brazil. It were used the historic series of precipitation data of 13 pluviometric stations located in the area and around the watershed. The minimum number of years was calculated from the relation between the number of years with observations and the stability of coefficients of determination. The station's area of coverage was determined from the relation between the coefficients of determination of the total monthly precipitation between each station and the base station (Santa Maria), and the linear distances between the base station and each station. From those equations, the distance between stations in which 80%, 85%, 90%, 95% e 99% of the values has concordance was determined. It was found that, to have a reasonable precision in the total monthly precipitation in the Vacacaí river watershed, it is necessary between 30 and 40 years of observation and, in December, January and February months the coverage of the pluviometric stations is less than 1.0km and on the other months to achieve a precision of 99% distances between 1.3 and 2.2km, 95% distances between 6.3 and 11.1km and 90% for distances between 12.5 and 22.5km.
Marchesana T.M.,UNIFRA |
Souzab A.M.,Federal University of Santa Maria |
Producao | Year: 2011
The practice of quality in university management is done with the engagement of the whole school community. The present work aims at identifying the weak and strong points of the teaching process based on students' opinions through multivariate analysis. For this study, there were elaborated questionnaires that considered the following categories of variables: students' self-evaluation, teacher's evaluation of the students and teachers' pedagogical practices. The data composed a sample that represented a participation of 87% of students enrolled in undergraduate courses at this institution. Through the internal consistency of factors, the results showed the validity of the construct that supports the teaching processes of the institution. Thus, this way of analyzing data favors a global result concerning students' perception of the teaching process.
PubMed | UNIFRA
Type: Journal Article | Journal: Progress in orthodontics | Year: 2011
In orthodontics the precise location of bracket placement on the teeth is a goal in order to individualize and optimize treatment outcome. The authors will describe the indirect bonding procedure with thermal glue transfer tray and brackets with positioning jigs for precise bracket placement.