Improvement of storage stability and physicochemical properties by addition of benzoguanamine in melamine‐formaldehyde resin synthesis

The improvement of melamine‐formaldehyde resin storage stability was achieved using benzoguanamine as partial replacement of melamine during synthesis (up to 15% substitution of melamine). The results showed that when benzoguanamine is added in the later stages of reaction, the resulting resins have improved storage stability (4 days or more, compared to 1 day in unmodified melamine‐formaldehyde resin). High‐pressure laminates produced with décor paper impregnated with the new developed resins showed surface properties equivalent to those obtained using commercial melamine‐formaldehyde resins. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45185.     

Preparation of an affinity cryogel column for lysozyme purification

Affinity cryogels were synthesized using tris(hydroxymethyl)aminomethane (Tris) as ligand for specific interactions with the lysozyme (LYZ). The cryogel was produced by cryo-copolymerization at ?12°C. A central composite rotational design 2² was used to optimize the immobilization procedure of the Tris on the cryogel. A maximum adsorption for LYZ (149.5 mg/g) was achieved when 376 mg/mL of Tris and 3.06 mol/L of sodium borohydride were used during the Tris immobilization. Chromatographic separation of LYZ from chicken egg white was done with a purity of 92.13%. Results showed that the affinity cryogel was a potential separation medium for LYZ purification.     

The fluidized-bed catalytic cracking unit building its future environment

Fluidized-bed catalytic cracking (FCC) has been considered as one of the largest catalytic process in the world. FCC is the name for a complex process unit that cracks long molecules from gas oils and residua into added value shorter fuel compounds; additionally, this process can be used to produce important petrochemical precursors, such as propylenes. Although historically FCC has been used to optimise production of light cycle oils, gasoline and olefins, nowadays is convenient to revisit its mission. In order to integrate FCC process inside current development and environment respect, it is necessary to see it as a very flexible process. This flexibility will require deeper knowledge about environmental impact of process operation and production objectives, transport phenomena and catalytic reactions taking place inside the riser, the main reactor of the FCC converter, and energy balance integrating energy recovered/generated in the regenerator. This work is devoted to briefly review some propositions about the use of FCC converters and how these aspects demand knowledge of riser reactors, change in the methodology to estimate effective reaction rates (consequence of variation of kinetic and transport phenomena, at catalyst scale and along the riser) and catalyst activity, as well as control actions and its effect on the energy balance of the converter; operation and environmental concerns surrounding this process are addressed. Finally, it tries to draw attention on some facts that need to be analysed in order to ensure the sustainable development of this important process in the short future.     

Acceleration tests using gasolines formulated with di-TAE, TAEE and MTBE ethers

This study evaluates the acceleration and performance of car engines fueled by gasoline formulated with di-tert-amyl ether (di-TAE), tert-amyl ethyl ether (TAEE), and methyl tert-butyl ether (MTBE), whose compositions contain an oxygen concentration of 2.7 wt.%. The performance tests were carried out in a roll dynamometer using a Fiat-Strada commercial vehicle equipped with open-loop electronic fuel injection. The use of ethers from partially renewable sources, such as di-TAE and TAEE in gasoline formulations, is an attractive alternative to reduce fossil fuel consumption. These ethers, both pure and in formulations, require a lower air/fuel ratio, since part of the oxygen needed to oxidize the fuel is already present in the molecule. The results obtained in acceleration tests using gasoline formulated with the di-TAE, TAEE and MTBE ethers indicated that the best acceleration response was obtained with the gasoline/TAEE mixture and the lowest specific consumption was with the gasoline/di-TAE mixture. TAEE is an adequate alternative to replace MTBE in Otto cycle internal combustion engines, since this compound is partially biorenewable and provides a comparable thermal efficiency and lower specific fuel consumption.     

Multi-objective optimization of water consumption for a methanol synthesis process

Clean Technologies and Environmental Policy - Methanol is an important product in chemical industries, having many applications: solvent, fuel and mainly being a feedstock for a large number of...     

An Output Feedback Position/Speed Regulator for a Torque—driven Inertia Wheel Pendulum

This paper presents a position/speed regulator for a torque–driven inertia wheel pendulum where only position measurements are available for feedback. Our contribution is to introduce a controller that does not need joint velocity measurements, and instead it uses the output of a linear filtering of weighted joint position errors to add damping. The proposed controller allows bringing the nonactuated pendulum rod towards its upright position, while the wheel spins asymptotically to a desired constant speed. A complete stability analysis based on Barbashin–Krasovskii’s theorem is presented together with an estimate of domain of attraction. Simulation results upon a torque–driven inertia wheel pendulum model illustrate the performance of the proposed controller.

     

Modification of the Marching Cubes Algorithm to Obtain a 3D Representation of a Planar Image

Programming and Computer Software - The registration of a 3D model over an image can be seen as the alignment of visual correspondences extracted from these two data. This is a challenging task and...     

High-Density Lipoproteins as Homeostatic Nanoparticles of Blood Plasma

It is well known that blood lipoproteins (LPs) are multimolecular complexes of lipids and proteins that play a crucial role in lipid transport. High-density lipoproteins (HDL) are a class of blood plasma LPs that mediate reverse cholesterol transport (RCT)—cholesterol transport from the peripheral tissues to the liver. Due to this ability to promote cholesterol uptake from cell membranes, HDL possess antiatherogenic properties. This function was first observed at the end of the 1970s to the beginning of the 1980s, resulting in high interest in this class of LPs. It was shown that HDL are the prevalent class of LPs in several types of living organisms (from fishes to monkeys) with high resistance to atherosclerosis and cardiovascular disorders. Lately, understanding of the mechanisms of the antiatherogenic properties of HDL has significantly expanded. Besides the contribution to RCT, HDL have been shown to modulate inflammatory processes, blood clotting, and vasomotor responses. These particles also possess antioxidant properties and contribute to immune reactions and intercellular signaling. Herein, we review data on the structure and mechanisms of the pleiotropic biological functions of HDL from the point of view of their evolutionary role and complex dynamic nature.     

Impact of sweetness on the sensory acceptance of passion fruit nectar in Brazilian geographic regions

Passion fruit is the fourth most consumed fruit by the Brazilian population, especially in the form of juice, usually associated with the addition of sucrose. This study aimed to evaluate the ideal sucrose concentration, and its impact on the consumer's acceptance of passion fruit nectar, sweetened with non-caloric sweeteners as sucrose replacers in five Brazilian geographic regions. The acceptance scores evaluated by anova and Tukey's Honestly Significant Difference test indicated that sucralose-sweetened samples were the most accepted, with no differences from the sucrose-sweetened sample (P < 0.05), with a positive purchase intention in the five regions studied (>50%). However, differences in the acceptance scores were observed for the other sweeteners among the regions. Despite the difference in the sweetness perception among the Brazilian geographic regions, it may not be the only determining factor in the acceptance of passion fruit nectar sweetened with non-caloric sweeteners.