Scielo RSS <![CDATA[Latin American applied research]]> vol. 44 num. 2 lang. es <![CDATA[SciELO Logo]]> <![CDATA[<b>The view of the process management in its diferent levels</b>: <b>a study case of process maturity</b>]]> The aim of this paper is to discuss the company's maturity level in the view of process management. As part of the discussion, there were made three study cases with the following characteristics: in large sized (company A) works in the field of toys with 350 employees; in medium sized (company B) that operates in the Amusement and leisure-industry technology with 80 employees and in midsize sized (company C) acts in the garment sector with 148 employees. In these study cases using as assessment tool the Maturity Model or the Rohloff Method, aiming at researching the management of the organization, methods, documentation, training, performance and portfolio of processes as well as the relationship between social networking and the multifunctional teams involved in the process, as the process owner, sponsors and facilitators. With the purpose of deepening the understanding of the processes for a period of three years, the researchers conducted systemic visits to the chosen companies, making on-site survey, observing the process, its characteristics and peculiarities. From the result it was possible to establish the correlation between the level of documentation of the companies and their levels of maturity on process management. <![CDATA[<b>High-sensitive bioactivity assay for hybrid nanostructured materials with plasmonic properties</b>]]> The binding of biotin to gold nanorods (Au-NRs) conjugated to neutravidin is accompanied by an increase in the fluorescence intensity of protein's tryptophan residues. Localized surface plasmon resonance (LSPR), combined with the known affinity of streptavidin for biotin, led to the development of a high-sensitive enzyme activity assay. <![CDATA[<b>Study of a pilot plant for the recovery of metals from spent alkaline and zinc-carbon batteries with biological sulphuric acid and polythionate production</b>]]> The recovery of Zn and Mn from spent alkaline and Zn-C batteries with a biohydrometallurgycal process was studied in a pilot plant that consists of an air-lift bioreactor with a sulphur packed bed where Acidithiobacillus thiooxidans produces an acid-reducing medium; a leaching reactor where the acid-reducing medium is mixed with the battery powder, and a recovery reactor where metals are recovered from the leaching liquor by electrolysis. Results show that with acid medium (350 mMENT#091;H+ENT#093;) produced in 12 days by Acidithiobacillus thiooxidans in the bioreactor, an extraction of 100% of Zn and 67% of the Mn present in the battery powder was reached. The presence of polythionates in the medium produced in the bioreactor allows the dissolution of the manganese. The solid remaining after bioleaching is a manganese oxide. The electrolysis of the leaching liquor produced a cathodic deposit of metallic Zn and an anodic deposit of a manganese oxide in one step at room temperature <![CDATA[<b>Ultrasound-assisted extraction of total flavonoids from leaves of <i>Syringa Oblata</i> Lindl</b>]]> Leaves of Syringa Oblata Lindl. possess some important biological activities, such as antibacterial, antiviral, anti-inflammatory and antioxidant activities. These biological properties are mainly attributed to total flavonoids content. In this paper, ultrasound-assisted extraction of total flavonoids from leaves of Syringa Oblata Lindl. was studied. Effects of several experimental parameters, such as concentration of extracting solvent, ratio of liquid to material, extraction temperature, and time of sonication on extraction efficiencies of total flavonoids were evaluated. The best extraction conditions were: 1 g plant sample with 20 mL of 50% ethanol, at 60°C for 50 min, obtaining a yield of total flavonoids of 92.00 ± 0.87 mg/g of plant. The results indicated that high amounts of total flavonoids can be extracted from leaves of Syringa Oblata Lindl. by ultrasound-assisted extraction technology <![CDATA[<b>Study on structure-activity relationship of 2E-3-phenyl propenyl acyloxy alkyl phosphonate molecular derivatives</b>]]> The quantum chemistry calculation of 2E-3-phenyl propenyl acyloxy alkyl phosphonate derivates was carried out to investigate the relationship between the structure and plant regulator activity of these compounds. All the compounds were studied by HF method with 6-31G* basis set using the PCM model within the self-consistent reaction field method to assess solvent effects, and then we established mathematical correlation between the properties and bioactivity of these compounds. The result showed that the bioactivity of these compounds has a linear relationship with the frontier orbital energy and other properties. At the same time, the active sites of these molecules were predicted. These compounds are electron acceptors. <![CDATA[<b>Kinetic and thermodynamic study of chlorobenzene adsorption from aqueous solutions onto granular activated carbon</b>]]> The adsorption of chlorobenzene (CB) from aqueous solutions using granular activated carbon (GAC) of different particle sizes was studied at temperatures from 283 to 303 K. Experimental kinetic values were fitted to a hyperbolic expression, which corresponds to the pseudo-second-order kinetic model. The model predictions are satisfactory in the whole range of particle sizes. Adsorption was found to be governed by intraparticle diffusion. For the adsorption system studied, mass transfer resistance becomes low enough at particle sizes below 1.68 mm to allow an adequate intraparticle transport of solute to the adsorption sites on sorbent surface. Isotherm data were fitted to Langmuir, Freundlich and Redlich-Peterson models. The equilibrium uptake capacity increased with temperature, indicating the endothermic nature of the process. The apparent isosteric heat of adsorption was determined by means of the Clausius-Clapeyron equation being in the 88-288 kJ/mol range. <![CDATA[<b>Natural convection boundary layer flow along a sphere embedded in a porous medium filled with a nanofluid</b>]]> A boundary-layer analysis is presented for the natural convec tion boundary layer flow about a sphere embedded in a porous medium filled with a nanofluid using Brinkman-Forchheimer-Darcy extended model. The model use d for the nanofluid inc orporates the ef fects of Brownian motion and thermophoresis. The governing partial differential equa tions are transformed into a set of nonsimilar equations and solved numerically by an efficient implicit, iterative, finite-difference method. Comparisons with previously published work are performed and excellent agreement is obtained. A parametric study of the physical parameters is conducted and a representative set of numerical results for the velocity, temperature, and nanoparticles volume fraction profiles as well as the local skin-friction coefficient, l ocal Nus selt and Sherwood numbers is illustrated graphically to show interesting features of the solutions. <![CDATA[<b>Facile synthesis and optical properties of PbO nanostructures</b>]]> PbO nanostructures were synthesized by the oxidation of lead sheets in a tube furnace under oxygen ambient using different temperatures, from 280 °C to 450 °C. X-ray diffraction patterns (XRD) indicated the formation of α-PbO nanostructures from the lead sheet with an increase in the temperature. Scanning electron microscope (SEM) results showed that flake-like shapes were starting to grow on the lead sheet that was placed in the 280 °C. In addition, the SEM studies showed nanoflake and nanoporous morphologies for the lead sheets that were placed at 330 °C and 450 °C, respectively. Raman measurements confirmed the XRD results and indicated two Raman active modes that belonged to the α-PbO phase for the nanoflakes and the nano-porous surface. The optical properties of the products were characterized using a photoluminescence (PL) technique. The PL results for the PbO nanoflakes and nanopores showed a peak in the visible region. <![CDATA[<b>Densities and excess molar volumes for binary solution of water + ethanol, + methanol and + propanol from (283.15 TO 313.15) K</b>]]> Densities for binary solutions of three alcohol (Ethanol, Methanol and propanol) with water over the whole composition range have been measured at temperatures from (283.15 to 313.15) K in 10 K intervals and atmospheric pressure (101.3 kPa). From these data, the excess molar volumes (V E) were calculated. The excess molar volumes for these systems were found to be negative across the whole composition and at all temperatures investigated. The excess molar volumes for ethanol and propanol + water become less negative with increasing temperature and conversely the excess molar volumes for methanol+ water become more negative with increasing temperature. The standard deviations (σ) for densities were calculated that ranged from 0.0000 to 0.001 <![CDATA[<b>A model of the arterial wall interaction with a blood pressure sensor transducer fixed in proximity</b>]]> MEMS technology is an option for the development of a pressure sensor which allows the monitoring of several bio-signals in humans. In this work, a comparison is made between the typical elasticity and viscosity presented in several arteries in the human body and those present in MEMS silicon microstructures based on membranes in proximity with an arterial wall. The main purpose is to identify which types of microstructures are mechanically compatible with human arteries. The ultimate goal is to integrate a blood pressure sensor which can be implanted in proximity with an artery. The expected benefits for this type of sensor are mainly the reduction in problems associated with the use of bulk devices through the day and during several days. Such a sensor could provide precise blood pressure readings in a continuous or periodic form, i.e. information that is especially important for some critical cases of hypertension patients. The modeling work involved in this paper, accounts for the analysis of micro displacements present in the membrane of a MEMs silicone microstructure placed directly on a human arterial wall, at different heart rates. The modeling includes the effects of elasticity and viscosity of the silicone structure on the pressure measurement. Additionally, the sensitivity of the membrane to detect slight variations in the blood pressure is presented. <![CDATA[<b>Strip thickness control in rolling mills using a gain scheduling technique</b>]]> This paper proposes a methodology of gain scheduling control for industrial rolling mills to test its feasibility and performance. Two controllers were proposed based on classical gain scheduling techniques acting on gap subsystem to compensate the process disturbances. One of them uses a proposed smoother control action mechanism to improve the process. A local control structure with an integrator in direct path between the controller and the plant was chosen to make the control synthesis more attractive. Optimal quadratic regulator method was used to get the local controllers gains. Simulation results are presented using real industrial data. They showed that the developed gain scheduling controllers are feasible for this process and lead to a less output thickness variations compared with another proposals. It is possible to use the developed control methodology for hot and cold rolling mills. <![CDATA[<b>A new utilization approach of natural soda ash</b>: <b>to manufacture sodium percarbonate</b>]]> Until now, natural soda ash ore is only used for manufacturing sodium carbonate and other common chemicals. As a fine chemical, the traditional method of sodium percarbonate takes sodium carbonate and hydrogen peroxide as raw materials. The primary goal of the present research is to explore a holistic route to manufacture sodium percarbonate from natural soda ash. The integrated approach avoids the operations of deep evaporation and calcination in the traditional manufacture process of sodium carbonate from natural soda ash. It also avoids the dissolution of merchandise sodium carbonate and any addition of salting-out agents in the production of sodium percarbonate. Taking Chagannuoer natural soda ash as raw material, the operating conditions were optimized by means of an orthogonal design L32(4(9)). The results indicate that the availability ratios of H2O2 and Na2CO3 are higher than 75% and 81% respectively under optimal conditions. The IR and XRD characterizations denote that the major component of the prepared product is Na2CO3·1.5H2O2. The research provides a case study for processes integration, and possibly contributes to the investigation of utilizing other natural resources. <![CDATA[<b>Effects of butter oil and whey proteins addition on viscoelastic properties of confectionary <i>dulce de leche</i></b>]]> The effect of butter oil and whey proteins addition on viscoelastic properties of confectionary Dulce de Leche was evaluated. A two factors experimental design (0-8 % p/v of butter oil and 0-1 % p/v of whey proteins) was analysed. Frequency sweep tests were carried out and for all formulations studied a weak gel like behavior was observed. Therefore, results were interpreted using a weak gel model for foods. It was observed that the rheological behavior of the sample with addition of whey proteins and butter oil is significantly different than the others because rheological units interact with greater strength. Even more, the sample without butter oil and with whey proteins addition is composed by less rheological units than the others. It is concluded that the whole addition of butter oil and whey proteins generates a stronger gel matrix, more appropriate for use in confectionary